publicationDate,title,abstract,id
2007-09-20,Spin wave resonances in La_{0.7}Sr_{0.3}MnO_{3} films: measurement of spin wave stiffness and anisotropy field,"We studied magnetic field dependent microwave absorption in epitaxial
La$_{0.7}$Sr$_{0.3}$MnO$_{3}$ films using an X-band Bruker ESR spectrometer. By
analyzing angular and temperature dependence of the ferromagnetic and spin-wave
resonances we determine spin-wave stiffness and anisotropy field. The spin-wave
stiffness as found from the spectrum of the standing spin-wave resonances in
thin films is in fair agreement with the results of inelastic neutron
scattering studies on a single crystal of the same composition [Vasiliu-Doloc
et al., J. Appl. Phys. \textbf{83}, 7343 (1998)].",0709.3204v2
2020-04-16,Magnetic resonance imaging of spin-wave transport and interference in a magnetic insulator,"Spin waves - the elementary excitations of magnetic materials - are prime
candidate signal carriers for low dissipation information processing. Being
able to image coherent spin-wave transport is crucial for developing
interference-based spin-wave devices. We introduce a platform for probing
coherent spin waves based on magnetic resonance imaging with electron spins in
diamond. Focusing on a thin-film magnetic insulator, we quantify spin-wave
amplitudes, visualize the dispersion, and demonstrate time-domain measurements
of spin-wave packets. We use our platform to study spin-wave interference,
revealing uni-directional, autofocused spin-wave patterns with
frequency-controlled numerical apertures. A theoretical analysis explains the
patterns in terms of chiral spin-wave excitation and stray-field coupling to
the sensor spins. These results pave the way for probing spin waves in
atomically thin magnets, even when embedded between opaque materials.",2004.07746v1
2015-10-20,Evaluation of Spin Waves and Ferromagnetic Resonance Contribution to the Spin Pumping in Ta/CoFeB Structure,"The spin waves and ferromagnetic resonance (FMR) contribution to the spin
pumping signal is studied in the Ta/CoFeB interface under different excitation
bias fields. Ferromagnetic resonance is excited utilizing a coplanar waveguide
and a microwave generator. Using a narrow waveguide of about 3 {\mu}m,
magnetostatic surface spin waves with large wavevector (k) of about 0.81
{\mu}m^-1 are excited. A large k value results in dissociation of spin waves
and FMR frequencies according to the surface spin wave dispersion relation.
Spin waves and FMR contribution to the spin pumping are calculated based on the
area under the Lorentzian curve fitting over experimental results. It is found
that the FMR over spin waves contribution is about 1 at large bias fields in
Ta/CoFeB structure. Based on our spin pumping results, we propose a method to
characterize the spin wave decay constant which is found to be about 5.5 {\mu}m
in the Ta/CoFeB structure at a bias field of 600 Oe.",1510.05745v1
2016-05-26,Spin gravitational resonance and graviton detection,"We develop a gravitational analogue of spin magnetic resonance, called spin
gravitational resonance, whereby a gravitational wave interacts with a magnetic
field to produce a spin transition. In particular, an external magnetic field
separates the energy spin states of a spin-1/2 particle, and the presence of
the gravitational wave produces a perturbation in the components of the
magnetic field orthogonal to the gravitational wave propagation. In this
framework we test Dyson's conjecture that individual gravitons cannot be
detected. Although we find no fundamental laws preventing single gravitons
being detected with spin gravitational resonance, we show that it cannot be
used in practice, in support of Dyson's conjecture.",1605.08316v1
2024-03-10,Spin Waves and Spin Currents in Magnon-Phonon Composite Resonator Induced by Acoustic Waves of Various Polarizations,"In this work, we present the results of a systematic experimental study of
linear and parametric spin wave resonant excitation accompanied by spin
currents (spin pumping) in a multifrequency composite bulk acoustic wave
resonator with a ZnO-YIG-GGG-YIG/Pt structure. The features of magnetic
dynamics excitation in YIG films due to magnetoelastic coupling with acoustic
thickness modes of various polarizations are studied. Acoustic spin waves and
spin pumping are detected by simultaneous frequency-field mapping of the
inverse spin Hall effect voltage and the resonant frequencies of thickness
extensional modes. In the parametric range of frequencies and fields, acoustic
spin pumping induced by both shear and longitudinal polarization modes was
observed. Linear acoustic spin waves are excited only by shear thickness
extensional modes because longitudinal acoustic waves do not couple with the
magnetic subsystem in linear regime.",2403.06274v1
2018-02-15,Effects of Symmetry Breaking in Resonance Phenomena,"We show that resonance phenomena can be treated as nonequilibrium phase
transitions. Resonance phenomena, similar to equilibrium phase transitions, are
accompanied by some kind of symmetry breaking and can be characterized by order
parameters. This is demonstrated for spin-wave resonance, helicon resonance,
and spin-reversal resonance.",1802.05589v1
2013-05-14,Ferrimagnetic Spin Wave Resonance and Superconductivity in Carbon Nanotubes,"The phenomenon of ferrimagnetic spin wave resonance [uncompensated
antiferromagnetic spin wave resonance] has been detected for the first time. It
has been observed in carbon nanotubes, produced by high energy ion beam
modification of diamond single crystals in $\ <{100}\ >$ direction.
Peculiarities of spin wave resonance observed allow to insist on the formation
in given nanotubes of $s^+$ superconductivity at room temperature, coexisting
with uncompensated antiferromagnetic ordering.",1305.3256v1
2018-05-09,Programmable control of spin-wave transmission in a domain-wall spin valve,"Active manipulation of spin waves is essential for the development of
magnon-based technologies. Here, we demonstrate programmable spin-wave
filtering by resetting the spin structure of a pinned 90$^\circ$ N\'{e}el
domain wall in a continuous CoFeB film with abrupt rotations of uniaxial
magnetic anisotropy. Using phase-resolved micro-focused Brillouin light
scattering and micromagnetic simulations, we show that broad 90$^\circ$
head-to-head or tail-to-tail magnetic domain walls are transparent to spin
waves over a broad frequency range. In contrast, magnetic switching to a
90$^\circ$ head-to-tail configuration produces much narrower domain walls at
the same pinning locations. Spin waves are strongly reflected by a resonance
mode in these magnetic domain walls. Based on these results, we propose a
magnetic spin-wave valve with two parallel domain walls. Switching the
spin-wave valve from an open to a close state changes the transmission of spin
waves from nearly 100% to 0% at the resonance frequency. This active control
over spin-wave transport could be utilized in magnonic logic devices or
non-volatile memory elements.",1805.03470v1
2011-09-05,Nucleon resonances in the fourth resonance region,"Nucleon and $\Delta$ resonances in the fourth resonance region are studied in
a multichannel partial-wave analysis which includes nearly all available data
on pion- and photo-induced reactions off protons. In the high-mass range, above
1850\,MeV, several alternative solutions yield a good description of the data.
For these solutions, masses, widths, pole residues and photo-couplings are
given. In particular, we find evidence for nucleon resonances with
spin-parities $J^P=1/2^+...7/2^+$. For one set of solutions, there are four
resonances forming naturally a spin-quartet of resonances with orbital angular
momentum L=2 and spin S=3/2 coupling to $J=1/2,...,7/2$. Just below 1.9\,GeV we
find a spin doublet of resonances with $J^P=1/2^-$ and $3/2^-$. Since a spin
partner with $J^P=5/2^-$ is missing at this mass, the two resonances form a
spin doublet which must have a symmetric orbital-angular-momentum wave function
with L=1. For another set of solutions, the four positive-parity resonances are
accompanied by mass-degenerate negative-parity partners -- as suggested by the
conjecture of chiral symmetry restoration. The possibility of a $J^P=1/2^+,
3/2^+$ spin doublet at 1900\,MeV belonging to a 20-plet is discussed.",1109.0970v1
2011-11-15,Spin waves in nanosized magnetic films,"We have studied spin excitations in nanosized magnetic films in the
Heisenberg model with magnetic dipole and exchange interactions by the spin
operator diagram technique. Dispersion relations of spin waves in thin magnetic
films (in two-dimensional magnetic monolayers and in two-layer magnetic films)
and the spin-wave resonance spectrum in N-layer structures are found. For thick
magnetic films generalized Landau-Lifshitz equations are derived from first
principles. Landau-Lifshitz equations have the integral (pseudodifferential)
form, but not differential one. Spin excitations are determined by simultaneous
solution of the Landau-Lifshitz equations and the equation for the
magnetostatic potential. For normal magnetized ferromagnetic films the spin
wave damping has been calculated in the one-loop approximation for a diagram
expansion of the Green functions at low temperature. In thick magnetic films
the magnetic dipole interaction makes a major contribution to the relaxation of
long-wavelength spin waves. Thin films have a region of low relaxation of
long-wavelength spin waves. In thin magnetic films four-spin-wave processes
take place and the exchange interaction makes a major contribution to the
damping. It is found that the damping of spin waves propagating in magnetic
monolayer is proportional to the quadratic dependence on the temperature and is
very low for spin waves with small wavevectors. Spin-wave devices on the base
of nanosized magnetic films are proposed -- tunable narrow-band spin-wave
filters with high quality at the microwave frequency range and field-effect
transistor (FET) structures contained nanosized magnetic films under the gate
electrode. Spin-wave resonances in nanosized magnetic films can be used to
construct FET structures operating in Gigahertz and Terahertz frequency bands.",1111.3532v1
1995-08-21,Standing Spin Wave Resonances in Manganite Films,"We report the first observation of spin wave resonances in 110 nm thick films
of LBMO. The spin wave stiffness follows $D$ = 47 (1 - 3 \times 10$_{-7}$
$T^{5/2}$) meV${\AA_2}$.",9508088v1
2014-12-04,Spin waves in semiconductor microcavities,"We show theoretically that a weakly interacting gas of spin-polarized
exciton-polaritons in a semiconductor microcavity supports propagation of spin
waves. The spin waves are characterised by a parabolic dispersion at small
wavevectors which is governed by the polariton-polariton interaction constant.
Due to spin-anisotropy of polariton-polariton interactions the dispersion of
spin waves depends on the orientation of the total polariton spin. For the same
reason, the frequency of homogeneous spin precession/polariton spin resonance
depends on their polarization degree.",1412.1758v2
2007-12-17,Field-induced spin excitations in Rashba-Dresselhaus two-dimensional electron systems probed by surface acoustic waves,"A spin-rotation symmetry in spin-orbit coupled two-dimensional electron
systems gives rise to a long-lived spin excitation that is robust against
short-range impurity scattering. The influence of a constant in-plane electric
field on this persistent spin helix is studied. To probe the field-induced
eigen-modes of the spin-charge coupled system, a surface acoustic wave is
exploited that provides the wave-vector for resonant excitation. The approach
takes advantage of methods worked out in the field of space-charge waves. Sharp
resonances in the field dependence of the in-plane and out-of-plane
magnetization are identified.",0712.2647v1
2024-03-19,Acoustoelectric non-local spin wave power detector for studying magnon-phonon coupling,"We have developed a simple detection scheme to study spin waves excited by
surface acoustic wave (SAW) in ferromagnetic thin films. Metallic antennas made
of Ta and a ferromagnetic element are placed along the SAW propagation path.
The SAW excites spin waves in the ferromagnetic element and induces
acoustoelectric current in the antennas, which are detected as a DC voltage.
The DC voltage takes an extremum at the spin wave resonance condition, which
demonstrates that the antenna acts as a non-local spin wave detector. The
antennas placed before and after the ferromagnetic element along the SAW
propagation path can probe spin wave excitation from reflected and transmitted
SAWs, respectively. Interestingly, we find characteristics of spin wave
excitations that are different for the reflected and transmitted SAWs: the
former excites spin waves with larger frequency with broader linewidth compared
to the latter. The results show that the antennas act as a non-local spin wave
power detector and can be used to map out the spin wave spectra in a unique
way, providing insights into the magnon-phonon coupling in magnetic
nanostructures fabricated on phononic SAW devices.",2403.12745v1
2012-01-25,Spin current induced by the sound wave,"The kinetics of conduction electrons interacting with the field of sound
waves in a constant magnetic field is studied. It is shown that the
longitudinal sound wave propagation occurs transverse spin conductivity, which
has a resonant character.",1201.5231v1
2021-06-08,Resonant excitation of twisted spin waves in magnetic vortices using rotating magnetic fields,"Twisted spin waves attracted research attentions lately and the orbital
angular momentum they carry may be utilized in communication and computing
technologies. In this work, we manifest by micromagnetic simulations that
twisted spin wave modes naturally exist in thick ferromagnetic disks. The
twisted spin waves can be readily stimulated using rotating magnetic field when
it is tuned to the eigenfrequency of corresponding modes. We analytically
derive dispersion relation of the twisted spin waves and the results agree well
with the numerical studies. Lastly, we demonstrate that the topological charge
of twisted spin waves can be controlled by the exciting field.",2106.04214v1
2021-06-28,Fully Resonant Magneto-elastic Spin-wave Excitation by Surface Acoustic Waves under Conservation of Energy and Linear Momentum,"We report on the resonant excitation of spin waves in micro-structured
magnetic thin films by surface acoustic waves (SAWs). The spin waves as well as
the acoustic waves are studied by micro-focused Brillouin light scattering
spectroscopy. Besides the excitation of the ferromagnetic resonance, a process
which does not fulfill momentum conservation, also the excitation of
finite-wavelength spin waves can be observed at low magnetic fields. Using
micromagnetic simulations, we verify that during this excitation both energy
and linear momentum are conserved and fully transferred from the SAW to the
spin wave.",2106.14705v3
2009-07-21,Non-resonant wave front reversal of spin waves used for microwave signal processing,"It is demonstrated that non-resonant wave front reversal (WFR) of spin-wave
pulses caused by pulsed parametric pumping can be effectively used for
microwave signal processing. When the frequency band of signal amplification by
pumping is narrower than the spectral width of the signal, the non-resonant WFR
can be used for the analysis of the signal spectrum. In the opposite case the
non-resonant WFR can be used for active (with amplification) filtering of the
input signal.",0907.3652v1
2009-01-01,Generation of GHZ and W states for stationary qubits in spin network via resonance scattering,"We propose a simple scheme to establish entanglement among stationary qubits
based on the mechanism of resonance scattering between them and a
single-spin-flip wave packet in designed spin network. It is found that through
the natural dynamical evolution of an incident single-spin-flip wave packet in
a spin network and the subsequent measurement of the output single-spin-flip
wave packet,multipartite entangled states among n stationary qubits,
Greenberger-Horne-Zeilinger (GHZ) and W states can be generated.",0901.0161v2
2008-06-24,Spin dynamics in point contacts to single ferromagnetic films,"Excitation of magnons or spin-waves driven by nominally unpolarized transport
currents in point contacts of normal and ferromagnetic metals is probed by
irradiating the contacts with microwaves. Two characteristic dynamic effects
are observed: a rectification of off-resonance microwave current by spin-wave
nonlinearities in the point contact conductance, and a resonant stimulation of
spin-wave modes in the nano-contact core by the microwave field. These
observations provide a direct evidence that the magnetoconductance effects
observed are due to GHz spin dynamics at the ferromagnetic interface driven by
the spin transfer torque effect of the transport current.",0806.3805v1
2010-06-27,Spin wave resonances in antiferromagnets,"Spin wave resonances with enormously large wave numbers corresponding to wave
vectors 10^5-10^6 cm^{-1} are observed in thin plates of FeBO3. The study of
spin wave resonances allows one to obtain information about the spin wave
spectrum. The temperature dependence of a non-uniform exchange constant is
determined for FeBO3. Considerable softening of the magnon spectrum resulting
from the interaction of magnons, is observed at temperatures above 1/3 of the
Neel temperature. The excitation level of spin wave resonances is found to
depend significantly on the inhomogeneous elastic distortions artificially
created in the sample. A theoretical model to describe the observed effects is
proposed.",1006.5192v1
2020-12-01,Towards a quantum interface between spin waves and paramagnetic spin baths,"Spin waves have risen as promising candidate information carriers for the
next generation of information technologies. Recent experimental demonstrations
of their detection using electron spins in diamond pave the way towards
studying the back-action of a controllable paramagnetic spin bath on the spin
waves. Here, we present a quantum theory describing the interaction between
spin waves and paramagnetic spins. As a case study we consider an ensemble of
nitrogen-vacancy spins in diamond in the vicinity of an Yttrium-Iron-Garnet
thin film. We show how the back-action of the ensemble results in strong and
tuneable modifications of the spin-wave spectrum and propagation properties.
These modifications include the full suppression of spin-wave propagation and,
in a different parameter regime, the enhancement of their propagation length by
$\sim 50\%$. Furthermore, we show how the spin wave thermal fluctuations induce
a measurable frequency shift of the paramagnetic spins in the bath. This shift
results in a thermal dispersion force that can be measured optically and/or
mechanically with a diamond mechanical resonator. In addition, we use our
theory to compute the spin wave-mediated interaction between the spins in the
bath. We show that all the above effects are measurable by state-of-the-art
experiments. Our results provide the theoretical foundation for describing
hybrid quantum systems of spin waves and spin baths, and establish the
potential of quantum spins as active control, sensing, and interfacing tools
for spintronics.",2012.00540v1
2012-08-09,Attenuation characteristics of spin pumping signal due to travelling spin waves,"The authors have investigated the contribution of the surface spin waves to
spin pumping. A Pt/NiFe bilayer has been used for measuring spin waves and spin
pumping signals simultaneously. The theoretical framework of spin pumping
resulting from ferromagnetic resonance has been extended to incorporate spin
pumping due to spin waves. Equations for the effective area of spin pumping due
to spin waves have been derived. The amplitude of the spin pumping signal
resulting from travelling waves is shown to decrease more rapidly with
precession frequency than that resulting from standing waves and show good
agreement with the experimental data.",1208.1837v1
2021-08-16,Losses of Interface Waves in Plasmonic and Gyrotropic Structures,"The loss mechanisms of slow interface waves in the layered resonant media are
examined and illustrated by the examples of (i) surface plasmon polaritons in
an isotropic plasma layer, (ii) magnetoplasmons in magnetised plasma and (iii)
spin waves in ferrimagnetic layers. It is shown that losses of all these
interface waves grow at the same rate of Im(gamma) ~ Re(gamma^3), where gamma
is the wavenumber. These abnormal losses are caused by vortices of the power
flow of the interface waves near their resonance cut-off. The basic properties
of the slow interface waves discussed in the paper are inherent to the waves of
hyperbolic type in the layered resonant media.",2108.07180v1
2023-05-04,Quasilinear theory of Brillouin resonances in rotating magnetized plasmas,"Both spin and orbital angular momentum can be exchanged between a rotating
wave and a rotating magnetized plasma. Through resonances the spin and orbital
angular momentum of the wave can be coupled to both the cyclotron rotation and
the drift rotation of the particles. It is however shown that the Landau and
cyclotron resonance conditions which classically describe resonant
energy-momentum exchange between waves and particles are no longer valid in a
rotating magnetized plasma column. In this case a new resonance condition which
involves a resonant matching between the wave frequency, the cyclotron
frequency modified by inertial effects and the harmonics of the guiding center
rotation is identified. A new quasilinear equation describing orbital and spin
angular momentum exchanges through these new Brillouin resonances is then
derived, and used to expose the wave driven radial current responsible for
angular momentum absorption.",2305.02671v1
2016-10-31,"Kinetic analysis of spin current contribution to spectrum of electromagnetic waves in spin-1/2 plasma, Part II: Dispersion dependencies","The dielectric permeability tensor for spin polarized plasmas derived in
terms of the spin-1/2 quantum kinetic model in six-dimensional phase space in
Part I of this work is applied for study of spectra of high-frequency
transverse and transverse-longitudinal waves propagating perpendicular to the
external magnetic field. Cyclotron waves are studied at consideration of waves
with electric field directed parallel to the external magnetic field. It is
found that the separate spin evolution modifies the spectrum of cyclotron
waves. These modifications increase with the increase of the spin polarization
and the number of the cyclotron resonance. Spin dynamics with no account of the
anomalous magnetic moment gives a considerable modification of spectra either.
The account of anomalous magnetic moment leads to a fine structure of each
cyclotron resonance. So, each cyclotron resonance splits on three waves.
Details of this spectrum and its changes with the change of spin polarization
are studied for the first and second cyclotron waves. A cyclotron resonance
existing at $\omega\approx0.001\mid\Omega_{e}\mid$ due to the anomalous
magnetic moment is also described, where $\mid\Omega_{e}\mid$ is the cyclotron
frequency. The ordinary waves does not have any considerable modification. The
electrostatic and electromagnetic Berstein modes are studied during the
analysis of waves propagating perpendicular to the external magnetic field with
the electric field perturbation directed perpendicular to the external field. A
modification of the oscillatory structure caused by the equilibrium spin
polarization is found in both regimes. Similar modification is found for the
extraordinary wave spectrum.",1611.00046v1
2016-07-20,Effect of isoscalar spin-triplet pairings on spin-isospin responses in $sd-$ shell nuclei,"The spin magnetic dipole transitions and the neutron-proton spin-spin
correlations in $sd-$shell even-even nuclei with $N=Z$ are investigated using
shell model wave functions. The isoscalar spin-triplet pairing correlation
provides a substantial quenching effect on the spin magnetic dipole
transitions, especially the isovector (IV) ones. Consequently, an enhanced
isoscalar spin-triplet pairing interaction influences the proton-neutron
spin-spin correlation deduced from the difference between the isoscalar (IS)
and the IV sum rule strengths. The effect of the $\Delta$ ($\Delta_{33}$
resonance)-hole coupling is examined in the IV spin transition and the
spin-spin correlations of the ground states.",1607.05881v2
2017-02-20,Parametric pumping of spin waves by acoustic waves,"The linear and nonlinear interactions between spin waves (magnons) and
acoustic waves (phonons) in magnetostrictive materials provide an exciting
opportunity for realizing novel microwave signal processing devices and
spintronic circuits. Here we demonstrate the parametric pumping of spin waves
by acoustic waves, the possibility of which has long been theoretically
anticipated but never experimentally realized. Spin waves propagating in a thin
film of yttrium iron garnet (YIG), a magnetostrictive ferrimagnet with low spin
and acoustic wave damping, are pumped using an acoustic resonator driven at
frequencies near twice the spin wave frequency. The observation of a
counter-propagating idler wave and a distinct pump threshold that increases
quadratically with frequency non-degeneracy are evidence of a nonlinear
parametric pumping process consistent with classical theory. This demonstration
of acoustic parametric pumping lays the groundwork for developing new
spintronic and microwave signal processing devices based on amplification and
manipulation of spin waves by efficient, spatially localized acoustic
transducers.",1702.06038v1
2009-05-28,Resonant Nonlinear Damping of Quantized Spin Waves in Ferromagnetic Nanowires,"We use spin torque ferromagnetic resonance to measure the spectral properties
of dipole-exchange spin waves in permalloy nanowires. Our measurements reveal
that geometric confinement has a profound effect on the damping of spin waves
in the nanowire geometry. The damping parameter of the lowest-energy quantized
spin wave mode depends on applied magnetic field in a resonant way and exhibits
a maximum at a field that increases with decreasing nanowire width. This
enhancement of damping originates from a nonlinear resonant three-magnon
confluence process allowed at a particular bias field value determined by
quantization of the spin wave spectrum in the nanowire geometry.",0905.4699v2
2013-10-23,Exchange-dominated Standing Spin Wave Excitations under microwave irradiation in Ni80Fe20 Thin Films,"We investigated the microwave-assisted DC voltages of ferromagnetic
resonances and exchangedominated standing spin wave excitations in two
different in-plane magnetized permalloy thin films via homodyne detection. The
line shapes of ferromagnetic resonance spectra and the dispersion curves of
ferromagnetic resonance and standing spin wave are in agreement of previous
studies, while further investigations of DC voltage spectra for these two
excitations reveal that 1. unlike ferromagnetic resonance signals, the
anti-symmetrical line shapes of standing spin wave excitations are not depend
on the electromagnetic relative phase of assisted microwave, and 2. linewidths
of their DC voltage spectra are distinct. The complicated spin dynamics of
standing spin wave is consequently discussed by applying
Landau-Lifshitz-Gilbert equation in term of exchange interaction.",1310.6108v1
2020-08-21,Magnons Parametric Pumping in Bulk Acoustic Waves Resonator,"We report on the experimental observation of excitation and detection of
parametric spin waves and spin currents in the bulk acoustic wave resonator.
The hybrid resonator consists of ZnO piezoelectric film, yttrium iron garnet
(YIG) films on gallium gadolinium garnet substrate, and a heavy metal Pt layer.
Shear bulk acoustic waves are electrically excited in the ZnO layer due to
piezoeffect at the resonant frequencies of the resonator. The magnetoelastic
interaction in the YIG film emerges magnons (spin waves) excitation by acoustic
waves either on resonator's eigenfrequencies or the half-value frequencies at
supercritical power. We investigate acoustic pumping of magnons at the
half-value frequencies and acoustic spin pumping from parametric magnons, using
the inverse spin Hall effect in the Pt layer. The constant electric voltage in
the Pt layer, depending on the frequency, the magnetic field, and the pump
power, was systematically studied. We explain the low threshold obtained (~0.4
mW) by the high efficiency of electric power transmission into the acoustic
wave in the resonator.",2008.09520v1
2013-10-30,Spin torque ferromagnetic resonance with magnetic field modulation,"We demonstrate a technique of broadband spin torque ferromagnetic resonance
(ST-FMR) with magnetic field modulation for measurements of spin wave
properties in magnetic nanostructures. This technique gives great improvement
in sensitivity over the conventional ST-FMR measurements, and application of
this technique to nanoscale magnetic tunnel junctions (MTJs) reveals a rich
spectrum of standing spin wave eigenmodes. Comparison of the ST-FMR
measurements with micromagnetic simulations of the spin wave spectrum allows us
to explain the character of low-frequency magnetic excitations in nanoscale
MTJs.",1310.7996v1
2018-11-07,Quantitative modeling of superconducting planar resonators with improved field homogeneity for electron spin resonance,"We present three designs for planar superconducting microwave resonators for
electron spin resonance (ESR) experiments. We implement finite element
simulations to calculate the resonance frequency and quality factors as well as
the three-dimensional microwave magnetic field distribution of the resonators.
One particular resonator design offers an increased homogeneity of the
microwave magnetic field while the other two show a better confinement of the
mode volume. We extend our model simulations to calculate the collective
coupling rate between a spin ensemble and a microwave resonator in the presence
of an inhomogeneous magnetic resonator field. Continuous-wave ESR experiments
of phosphorus donors in $^\mathrm{nat}$Si demonstrate the feasibility of our
resonators for magnetic resonance experiments. We extract the collective
coupling rate and find a good agreement with our simulation results,
corroborating our model approach. Finally, we discuss specific application
cases for the different resonator designs.",1811.02971v2
2005-08-26,Resonance mode in $B_{1g}$ Raman scattering -- a way to distinguish between spin-fluctuation and phonon-mediated $d-$wave superconductivity,"We argue that Raman scattering in $B_{1g}$ symmetry allows one to distinguish
between phonon-mediated and magnetically-mediated $d-$wave superconductivity.
In spin mediated superconductors, $B_{1g}$ Raman intensity develops a resonance
at a frequency $\omega_{res} < 2\Delta_{max}$, whose origin is similar to a
neutron resonance. In phonon-mediated $d-$wave superconductors, such a
resonance does not develop. Several extensions of the argument are presented.",0508643v2
2013-08-14,Electrical Detection of Spin Wave Resonance in a Permalloy Thin Strip,"We investigated the microwave-induced DC response of spin wave resonance
(SWR) in a permalloy thin strip via electrical detection. Our experimental
results obtained by sweeping the external field reveal that: 1. the amplitude
of SWR signals depend on the direction of external field and, 2. unlike the DC
response of ferromagnetic resonance, SWR spectra are always anti-symmetrical.
The spin dynamics are discussed based on these unusual signals in resonant
condition.",1308.3069v1
2019-03-28,Acoustic excitation and electrical detection of spin waves and spin currents in hypersonic bulk waves resonator with YIG/Pt system,"We report on the self-consisted semi-analytical theory of magnetoelastic
excitation and electrical detection of spin waves and spin currents in
hypersonic bulk acoustic waves resonator with ZnO-GGG-YIG/Pt layered structure.
Electrical detection of acoustically driven spin waves occurs due to spin
pumping from YIG to Pt and inverse spin Hall (ISHE) effect in Pt as well as due
to electrical response of ZnO piezotransducer. The frequency-field dependences
of the resonator frequencies and ISHE voltage $U_{ISHE}$ are correlated with
experimental ones observed previously. Their fitting allows to determine some
magnetic and magnetoelastic parameters of YIG. The analysis of the YIG film
thickness influence on $U_{ISHE}$ gives the possibility to find the optimal
thickness for maximal $U_{ISHE}$ value.",1903.12130v2
2020-04-01,Development of planar microstrip resonators for electron spin resonance spectroscopy,"This work focuses on the development of planar microwave resonators which are
to be used in electron spin resonance spectroscopic studies. Two half
wavelength microstrip resonators of different geometrical shapes, namely
straight ribbon and omega, are fabricated on commercially available copper clad
microwave laminates. Both resonators have a characteristic impedance of 50
{\Omega}. We have performed electromagnetic field simulations for the two
microstrip resonators and have extracted practical design parameters which were
used for fabrication. The effect of the geometry of the resonators on the
quasi-transverse electromagnetic (quasi-TEM) modes of the resonators is noted
from simulation results. The fabrication is done using optical lithography
technique in which laser printed photomasks are used. This rapid prototyping
technique allows us to fabricate resonators in a few hours with accuracy up to
6 mils. The resonators are characterized using a Vector Network Analyzer. The
fabricated resonators are used to standardize a home built low-temperature
continuous wave electron spin resonance (CW-ESR) spectrometer which operates in
S-band, by capturing the absorption spectrum of the free radical DPPH, at both
room temperature and 77 K. The measured value of g-factor using our resonators
is consistent with the values reported in literature. The designed half
wavelength planar resonators will be eventually used in setting up a pulsed
electron spin resonance spectrometer by suitably modifying the CW-ESR
spectrometer.",2004.00457v1
2017-07-27,Electron spin resonance for the detection of long-range spin nematic order,"In this paper we propose that electron spin resonance (ESR) measurements
enable us to detect the long-range spin nematic order. We show that the
frequency of the paramagnetic resonance peak in the ESR spectrum is shifted by
the ferroquadrupolar order parameter together with other quantities. The
ferroquadrupolar order parameter is extractable from the angular dependence of
the frequency shift. In contrast, the antiferroquadrupolar order parameter is
usually invisible in the frequency shift. Instead, the long-range
antiferroquadrupolar order yields a characteristic resonance peak in the ESR
spectrum, which we call a magnon-pair resonance peak. This resonance
corresponds to the excitation of the bound magnon pair at the wave vector $\bm
k={\bm 0}$. Reflecting the condensation of bound magnon pairs, the field
dependence of the magnon-pair resonance frequency shows a singular upturn at
the saturation field. Moreover, the intensity of the magnon-pair resonance peak
shows a characteristic angular dependence and it vanishes when the magnetic
field is parallel to one of the axes that diagonalize the weak anisotropic
interactions. We confirm these general properties of the magnon-pair resonance
peak in the spin nematic phase by studying an $S=1$ bilinear-biquadratic model
on the square lattice in the linear flavor-wave approximation. In addition, we
argue applications to the $S=1/2$ frustrated ferromagnets and also the $S=1/2$
orthogonal dimer spin system SrCu$_2$(BO$_3$)$_2$, both of which are candidate
materials of spin nematics. Our theory for the antiferroquadrupolar ordered
phase is consistent with many features of the magnon-pair resonance peak
experimentally observed in the low-magnetization regime of
SrCu$_2$(BO$_3$)$_2$.",1707.08784v2
2020-11-03,Gravito-magnetic resonance in the field of a gravitational wave,"Using the construction of the Fermi frame, the field of a gravitational wave
can be described in terms of gravito-electromagnetic fields that are transverse
to the propagation direction and orthogonal to each other. In particular, the
gravito-magnetic field acts on spinning particles and we show that, due to the
action of the gravitational wave field, a new phenomenon, that we call
gravito-magnetic resonance, may appear. We give both a classical and a quantum
description of this phenomenon and suggest that it can be used as the basis for
a new type of gravitational wave detectors. Our results highlight the
effectiveness of collective spin excitations, e.g. spin waves in magnetized
materials, in detecting high frequency gravitational waves. Here we suggest
that, when gravitational waves induce a precession of the electron spin, power
is released in the ferromagnetic resonant mode endowed with quadrupole symmetry
of a magnetized sphere. This offers a possible path to the detection of the
gravito-magnetic effects of a gravitational wave.",2011.01663v1
2004-10-08,Spin-dependent resonant tunneling in symmetrical double-barrier structure,"A theory of resonant spin-dependent tunneling has been developed for
symmetrical double-barrier structures grown of non-centrosymmetrical
semiconductors. The dependence of the tunneling transparency on the spin
orientation and the wave vector of electrons leads to (i) spin polarization of
the transmitted carriers in an in-plane electric field, (ii) generation of an
in-plane electric current under tunneling of spin-polarized carriers. These
effects originated from spin-orbit coupling-induced splitting of the resonant
level have been considered for double-barrier tunneling structures.",0410198v1
2021-01-08,Compact tunable YIG-based RF resonators,"We report on the design, fabrication, and characterization of compact tunable
yttrium iron garnet (YIG) based RF resonators based on $\mu$m-sized spin-wave
cavities. Inductive antennas with both ladder and meander configurations were
used as transducers between spin waves and RF signals. The excitation of
ferromagnetic resonance and standing spin waves in the YIG cavities led to
sharp resonances with quality factors up to 350. The observed spectra were in
excellent agreement with a model based on the spin-wave dispersion relations in
YIG, showing a high magnetic field tunability of about 29 MHz/mT.",2101.02909v4
2003-12-23,Gravitational waves interacting with a spinning charged particle in the presence of a uniform magnetic field,"The equations which determine the response of a spinning charged particle
moving in a uniform magnetic field to an incident gravitational wave are
derived in the linearized approximation to general relativity. We verify that
1) the components of the 4-momentum, 4-velocity and the components of the
spinning tensor, both electric and magnetic moments, exhibit resonances and 2)
the co-existence of the uniform magnetic field and the GW are responsible for
the resonances appearing in our equations. In the absence of the GW, the
magnetic field and the components of the spin tensor decouple and the magnetic
resonances disappear.",0312102v1
2021-12-16,Parametric resonance of spin waves in ferromagnetic nanowires tuned by spin Hall torque,"We present a joint experimental and theoretical study of parametric resonance
of spin wave eigenmodes in Ni$_{80}$Fe$_{20}$/Pt bilayer nanowires. Using
electrically detected magnetic resonance, we measure the spectrum of spin wave
eigenmodes in transversely magnetized nanowires and study parametric excitation
of these eigenmodes by a microwave magnetic field. We also develop an
analytical theory of spin wave eigenmodes and their parametric excitation in
the nanowire geometry that takes into account magnetic dilution at the nanowire
edges. We measure tuning of the parametric resonance threshold by antidamping
spin Hall torque from a direct current for the edge and bulk eigenmodes, which
allows us to independently evaluate frequency, damping and ellipticity of the
modes. We find good agreement between theory and experiment for parametric
resonance of the bulk eigenmodes but significant discrepancies arise for the
edge modes. The data reveals that ellipticity of the edge modes is
significantly lower than expected, which can be attributed to strong
modification of magnetism at the nanowire edges. Our work demonstrates that
parametric resonance of spin wave eigenmodes is a sensitive probe of magnetic
properties at edges of thin-film nanomagnets.",2112.09222v1
2016-05-20,Two-dimensional terahertz magnetic resonance spectroscopy of collective spin waves,"Nonlinear manipulation of nuclear and electron spins is the basis for all
advanced methods in magnetic resonance including multidimensional nuclear
magnetic and electron spin resonance spectroscopies, magnetic resonance
imaging, and in recent years, quantum control over individual spins. The
methodology is facilitated by the ease with which the regime of strong coupling
can be reached between radiofrequency or microwave magnetic fields and nuclear
or electron spins respectively, typified by sequences of magnetic pulses that
control the magnetic moment directions. The capabilities meet a bottleneck,
however, for far-infrared magnetic resonances characteristic of correlated
electron materials, molecular magnets, and proteins that contain high-spin
transition metal ions. Here we report the development of two-dimensional
terahertz magnetic resonance spectroscopy and its use for direct observation of
the nonlinear responses of collective spin waves (magnons). The spectra show
magnon spin echoes and 2-quantum signals that reveal pairwise correlations
between magnons at the Brillouin zone center. They also show resonance-enhanced
second-harmonic and difference-frequency signals. Our methods are readily
generalizable to multidimensional magnetic resonance spectroscopy and nonlinear
coherent control of terahertz-frequency spin systems in molecular complexes,
biomolecules, and materials.",1605.06476v3
2022-06-21,Faraday patterns in spin-orbit coupled Bose-Einstein condensates,"We study the Faraday patterns generated by spin-orbit-coupling induced
parametric resonance in a spinor Bose-Einstein condensate with repulsive
interaction. The collective elementary excitations of the Bose-Einstein
condensate, including density waves and spin waves, are coupled as the result
of the Raman-induced spin-orbit coupling and a quench of the relative phase of
two Raman lasers without the modulation of any of the system's parameters. We
observed several higher parametric resonance tongues at integer multiples of
the driving frequency and investigated the interplay between Faraday
instabilities and modulation instabilities when we quench the
spin-orbit-coupled Bose-Einstein condensate from zero-momentum phase to
plane-wave phase. If the detuning is equal to zero, the wave number of
combination resonance barely changes as the strength of spin-orbit coupling
increases. If the detuning is not equal to zero after a quench, a single
combination resonance tongue will split into two parts.",2206.10222v1
2003-05-18,New Resonances Along with Cyclotron Resonance in Heterostructures,"The usual cyclotron resonance occurs at \omega_c=eB/m*c which is independent
of spin. The new resonances depend on spin. The new resonances occur at
\omega_{c\pm}=(1/2)g_{\pm}eB/m*c where (1/2)g_{\pm}= {\it l}+(1/2)\pm s/(2{\it
l}+1). The energy in the centre of two new frequencies varies as the square
root of the 2-dimensional electrons due to spin excess in the Gaussian model.
The frequencies \omega_{c\pm} are linearly proportional to the magnetic field
except near crossing point where the linear combination of wave functions must
be made.",0305415v1
2007-10-04,Quantum-mechanical Landau-Lifshitz equation,"Quantum-mechanical analogue of Landau-Lifshitz equation has been derived. It
has been established that Landau-Lifshitz equation is fundamental physical
equation underlying the dynamics of spectroscopic transitions and transitional
phenomena. New phenomenon is predicted: electrical spin wave resonance (ESWR)
being to be electrical analogue of magnetic spin wave resonance.",0710.1058v3
2001-02-02,Gate-Controlled Electron Spin Resonance in a GaAs/AlGaAs Heterostructure,"The electron spin resonance (ESR) of two-dimensional electrons is
investigated in a gated GaAs/AlGaAs heterostructure. We found that the ESR
resonance frequency can be turned by means of a gate voltage. The front and
back gates of the heterostructure produce opposite g-factor shift, suggesting
that electron g-factor is being electrostatically controlled by shifting the
equilibrium position of the electron wave function from one epitaxial layer to
another with different g-factors.",0102044v1
2017-05-03,Spin Resonance and Magnetic Order in an Unconventional Superconductor,"Unconventional superconductivity in many materials is believed to be mediated
by magnetic fluctuations. It is an open question how magnetic order can emerge
from a superconducting condensate and how it competes with the magnetic spin
resonance in unconventional superconductors. Here we study a model d-wave
superconductor that develops spin-density wave order, and find that the spin
resonance is unaffected by the onset of static magnetic order. This result
suggests a scenario, in which the resonance in Nd0.05Ce0.95CoIn5 is a
longitudinal mode with fluctuating moments along the ordered magnetic moments.",1705.01255v2
2021-09-10,Electrical spectroscopy of the spin-wave dispersion and bistability in gallium-doped yttrium iron garnet,"Yttrium iron garnet (YIG) is a magnetic insulator with record-low damping,
allowing spin-wave transport over macroscopic distances. Doping YIG with
gallium ions greatly reduces the demagnetizing field and introduces a
perpendicular magnetic anisotropy, which leads to an isotropic spin-wave
dispersion that facilitates spin-wave optics and spin-wave steering. Here, we
characterize the dispersion of a gallium-doped YIG (Ga:YIG) thin film using
electrical spectroscopy. We determine the magnetic anisotropy parameters from
the ferromagnetic resonance frequency and use propagating spin wave
spectroscopy in the Damon-Eshbach configuration to detect the small spin-wave
magnetic fields of this ultrathin weak magnet over a wide range of wavevectors,
enabling the extraction of the exchange constant $\alpha=1.3(2)\times10^{-12}$
J/m. The frequencies of the spin waves shift with increasing drive power, which
eventually leads to the foldover of the spin-wave modes. Our results shed light
on isotropic spin-wave transport in Ga:YIG and highlight the potential of
electrical spectroscopy to map out the dispersion and bistability of
propagating spin waves in magnets with a low saturation magnetization.",2109.05045v1
2004-04-20,Wave function collapses in a single spin magnetic resonance force microscopy,"We study the effects of wave function collapses in the oscillating cantilever
driven adiabatic reversals (OSCAR) magnetic resonance force microscopy (MRFM)
technique. The quantum dynamics of the cantilever tip (CT) and the spin is
analyzed and simulated taking into account the magnetic noise on the spin. The
deviation of the spin from the direction of the effective magnetic field causes
a measurable shift of the frequency of the CT oscillations. We show that the
experimental study of this shift can reveal the information about the average
time interval between the consecutive collapses of the wave function",0404105v1
2007-09-21,Spin-Peierls transition in carbynoid conductors: infrared absorption study,"The results of IR-studies in quasi-1D carbynoid films produced by
dehydrohalogenation of poly(vinilidene fluoride) are in good agreement with the
assumption that carbynoid films studied are generalized spin -Peierls
conductors, the metal to insulator transition in which can be described in the
frame of t-J model. Residual atoms of fluorine, hydrogen and atoms of main
technological impurity oxygen in the form of various complexes in interchain
space are suggested to be spin - (or joint spin - and electrical) conductivity
dopants. Antiferroelectric spin wave resonance (AFESWR) being to be optical
analogue of antiferromagnetic spin wave resonance has been identified for the
first time. Electric spin-Peierls polaron lattice in C-C -bonds is proposed to
be responsible for the observed AFESWR both in starting PWDF films and in
carbynoid B-films (the samples with the least impurity content). Electric spin
moment with pure imaginary value predicted by Dirac as early as 1928 was
identified for the first time. Electric spin-Peierls polarons are proposed to
be electric spin moment carriers. It has been established that topological
solitons, earlier called spin-Peierls solitons (SPS), are simultaneously
active, unlike to topological solitons with nonzero spin in
\textit{trans}-polyacetylene, in both optical and magnetic resonance spectra.It
is explained in suggestion that SPS possess by both electric and magnetic spin
moments which can be considered as two components of complex electromagnetic
spin vector as a single whole. SPS proposed to be consisting of two coupled
domain walls in both magnetic and electric generalized spin density wave
(GSDW), produced by electromagnetic spin-Peierls transition in its generalized
form in $\pi$ - and $\sigma$ -subsystems of carbynoids.",0709.3382v2
2018-06-07,Magnetic domain walls as broadband spin wave and elastic magnetisation wave emitters,"We report on the direct observation of spin wave and elastic wave emission
from magnetic domain walls in ferromagnetic thin films. Driven by alternating
homogeneous magnetic fields the magnetic domain walls act as coherent
magnetisation wave sources. Directional and low damped elastic waves below and
above the ferromagnetic resonance are excited. The wave vector of the
magnetoelastically induced acoustic shear waves is linearly tuned by varying
the excitation frequency. Domain wall emitted magnetostatic surface spin waves
occur at higher frequencies, which characteristics are confirmed by
micromagnetic simulations. The distinct modes of magnetisation wave excitation
from micromagnetic objects are a general physical phenomenon relevant for
dynamic magnetisation processes in structured magnetic films. Magnetic domain
walls can act as reconfigurable antennas for spin wave and elastic wave
generation with control of the wave orientation.",1806.02646v1
2007-05-29,Resonant scattering of spin waves from a region of inhomogeneous magnetic field in a ferromagnetic film,"The transmission of a dipole-dominated spin wave in a ferromagnetic film
through a localised inhomogeneity in the form of a magnetic field produced by a
dc current through a wire placed on the film surface was studied experimentally
and theoretically. It was shown that the amplitude and phase of the transmitted
wave can be simultaneously affected by the current induced field, a feature
that will be relevant for logic based on spin wave transport.
  The direction of the current creates either a barrier or well for spin wave
transmission. The main observation is that the current dependence of the
amplitude of the spin wave transmitted through the well inhomogeneity is
non-monotonic. The dependence has a minimum and an additional maximum. A theory
was constructed to clarify the nature of the maximum. It shows that the
transmission of spin waves through the inhomogeneity can be considered as a
scattering process and that the additional maximum is a scattering resonance.",0705.4191v1
2015-06-09,Traveling surface spin-wave resonance spectroscopy using surface acoustic waves,"Coherent gigahertz-frequency surface acoustic waves (SAWs) traveling on the
surface of a piezoelectric crystal can, via the magnetoelastic interaction,
resonantly excite traveling spin waves in an adjacent thin-film ferromagnet.
These excited spin waves, traveling with a definite in-plane wave-vector q
enforced by the SAW, can be detected by measuring changes in the
electro-acoustical transmission of a SAW delay line. Here, we provide a first
demonstration that such measurements constitute a precise and quantitative
technique for spin-wave spectroscopy, providing a means to determine both
isotropic and anisotropic contributions to the spin-wave dispersion and
damping. We demonstrate the effectiveness of this spectroscopic technique by
measuring the spin-wave properties of a Ni thin film for a large range of wave
vectors,q = 2.5 x 10^4 - 8 x 10^4 cm^(-1), over which anisotropic dipolar
interactions vary from being negligible to quite significant.",1506.03056v3
2013-06-16,Zero-Field Fiske Resonance Coupled with Spin-waves in Ferromagnetic Josephson Junctions,"AC Josephson current density in a Josephson junction with DC bias is
spatially modulated by an external magnetic field, and induces an
electromagnetic (EM) field inside the junction. The current-voltage ($I$-$V$)
curve exhibits peaks due to the resonance between the EM field and the
spatially modulated AC Josephson current density. This is called {\it Fiske
resonance}. Such a spatially modulated Josephson current density can be also
induced by a non-uniform insulating barrier and the Fiske resonance appears
without external magnetic field. This is called zero-field Fiske resonance
(ZFFR). In this paper, we theoretically study the ZFFR coupled with spin-waves
in a superconductor/ferromagnetic insulator/superconductor junction
(ferromagnetic Josephson junction) with a non-uniform ferromagnetic insulating
barrier. The resonant mode coupled with spin-waves can be induced without
external magnetic field. We find that the $I$-$V$ curve shows resonant peaks
associated with composite excitations of spin-waves and the EM field in the
junction. The voltage at the resonance is obtained as a function of the normal
modes of EM field. The ZFFRs coupled with spin-waves are found as peak
structures in the DC Josephson current density as a function of bias voltage.",1306.3652v2
2012-11-05,Spin Dynamics and Resonant Inelastic X-ray Scattering in Chromium with Commensurate Spin-Density Wave Order,"We theoretically investigate spin dynamics and $L_3$-edge resonant inelastic
X-ray scattering (RIXS) of Chromium with commensurate spin-density wave (SDW)
order, based on a multi-band Hubbard model composed of 3$d$ and 4$s$ orbitals.
Obtaining the ground state with the SDW mean-field approximation, we calculate
the dynamical transverse and longitudinal spin susceptibility by using
random-phase approximation. We find that a collective spin-wave excitation seen
in inelastic neutron scattering hardly damps up to $\sim$0.6 eV. Above the
energy, the excitation overlaps individual particle-hole excitations as
expected, leading to broad spectral weight. On the other hand, the collective
spin-wave excitation in RIXS spectra has a tendency to be masked by large
spectral weight coming from particle-hole excitations with various orbital
channels. This is in contrast with inelastic neutron scattering, where only
selected diagonal orbital channels contribute to the spectral weight. However,
it may be possible to detect the spin-wave excitation in RIXS experiments in
the future if resolution is high enough.",1211.1598v2
2012-08-17,Spin-wave excitations and superconducting resonant mode in Cs(x)Fe(2-y)Se2,"We report neutron inelastic scattering measurements on the normal and
superconducting states of single-crystalline Cs0.8Fe1.9Se2. Consistent with
previous measurements on Rb(x)Fe(2-y)Se2, we observe two distinct spin
excitation signals: (i) spin-wave excitations characteristic of the block
antiferromagnetic order found in insulating A(x)Fe(2-y)Se2 compounds, and (ii)
a resonance-like magnetic peak localized in energy at 11 meV and at an in-plane
wave vector of (0.25, 0.5). The resonance peak increases below Tc = 27 K, and
has a similar absolute intensity to the resonance peaks observed in other
Fe-based superconductors. The existence of a magnetic resonance in the spectrum
of Rb(x)Fe(2-y)Se2 and now of Cs(x)Fe(2-y)Se2 suggests that this is a common
feature of superconductivity in this family. The low energy spin-wave
excitations in Cs0.8Fe1.9Se2 show no measurable response to superconductivity,
consistent with the notion of spatially separate magnetic and superconducting
phases.",1208.3610v2
1996-06-04,Direct Hopf Bifurcation in Parametric Resonance of Hybridized Waves,"We study parametric resonance of interacting waves having the same wave
vector and frequency. In addition to the well-known period-doubling instability
we show that under certain conditions the instability is caused by a Hopf
bifurcation leading to quasiperiodic traveling waves. It occurs, for example,
if the group velocities of both waves have different signs and the damping is
weak. The dynamics above the threshold is briefly discussed. Examples
concerning ferromagnetic spin waves and surface waves of ferro fluids are
discussed.",9605006v1
2005-02-08,Landau Damping of Spin Waves in Trapped Boltzmann Gases,"A semiclassical method is used to study Landau damping of transverse
pseudo-spin waves in harmonically trapped ultracold gases in the collisionless
Boltzmann limit. In this approach, the time evolution of a spin is calculated
numerically as it travels in a classical orbit through a spatially dependent
mean field. This method reproduces the Landau damping results for spin-waves in
unbounded systems obtained with a dielectric formalism. In trapped systems, the
simulations indicate that Landau damping occurs for a given spin-wave mode
because of resonant phase space trajectories in which spins are ""kicked out"" of
the mode (in spin space). A perturbative analysis of the resonant and nearly
resonant trajectories gives the Landau damping rate, which is calculated for
the dipole and quadrupole modes as a function of the interaction strength. The
results are compared to a numerical solution of the kinetic equation by Nikuni
et al.",0502189v1
2017-05-09,Topological spin dynamics in cubic FeGe near room temperature,"Understanding spin-wave dynamics in chiral magnets is a key step for the
development of high-speed, spin-wave based spintronic devices that take
advantage of chiral and topological spin textures for their operation. Here we
present an experimental and theoretical study of spin-wave dynamics in a cubic
B20 FeGe single crystal. Using the combination of waveguide microwave
absorption spectroscopy (MAS), micromagnetic simulations, and analytical
theory, we identify the resonance dynamics in all magnetic phases (field
polarized, conical, helical, and skyrmion phases). Because the resonance
frequencies of specific chiral spin textures are unique, quantitative agreement
between our theoretical predictions and experimental findings for all resonance
frequencies and spin wave modes enables us to unambiguously identify chiral
magnetic phases and to demonstrate that MAS is a powerful tool to efficiently
extract a magnetic phase diagram. These results provide a new tool to
accelerate the integration of chiral magnetic materials into spintronic
devices.",1705.03397v1
2022-05-31,Spin-Acoustic Control of Silicon Vacancies in 4H Silicon Carbide,"We demonstrate direct, acoustically mediated spin control of naturally
occurring negatively charged silicon monovacancies (V$_{Si}^-$) in a high
quality factor Lateral Overtone Bulk Acoustic Resonator fabricated out of high
purity semi-insulating 4H-Silicon Carbide. We compare the frequency response of
silicon monovacancies to a radio-frequency magnetic drive via
optically-detected magnetic resonance and the resonator's own radio-frequency
acoustic drive via optically-detected spin acoustic resonance and observe a
narrowing of the spin transition to nearly the linewidth of the driving
acoustic resonance. We show that acoustic driving can be used at room
temperature to induce coherent population oscillations. Spin acoustic resonance
is then leveraged to perform stress metrology of the lateral overtone bulk
acoustic resonator, showing for the first time the stress distribution inside a
bulk acoustic wave resonator. Our work can be applied to the characterization
of high quality-factor micro-electro-mechanical systems and has the potential
to be extended to a mechanically addressable quantum memory.",2205.15488v1
2024-01-12,Spin Resonance Spectroscopy with an Electron Microscope,"Coherent spin resonance methods, such as nuclear magnetic resonance and
electron spin resonance spectroscopy, have led to spectrally highly sensitive,
non-invasive quantum imaging techniques. Here, we propose a pump-probe spin
resonance spectroscopy approach, designed for electron microscopy, based on
microwave pump fields and electron probes. We investigate how quantum spin
systems couple to electron matter waves through their magnetic moments and how
the resulting phase shifts can be utilized to gain information about the states
and dynamics of these systems. Notably, state-of-the-art transmission electron
microscopy provides the means to detect phase shifts almost as small as that
due to a single electron spin. This could enable state-selective observation of
spin dynamics on the nanoscale and indirect measurement of the environment of
the examined spin systems, providing information, for example, on the atomic
structure, local chemical composition and neighboring spins.",2401.06496v1
2006-06-02,Magnetically tuned spin dynamics resonance,"We present the experimental observation of a magnetically tuned resonance
phenomenon resulting from spin mixing dynamics of ultracold atomic gases. In
particular we study the magnetic field dependence of spin conversion in F=2
87Rb spinor condensates in the crossover from interaction dominated to
quadratic Zeeman dominated dynamics. We discuss the observed phenomenon in the
framework of spin dynamics as well as matter wave four wave mixing. Furthermore
we show that the validity range of the single mode approximation for spin
dynamics is significantly extended in the regime of high magnetic field.",0606046v1
2008-03-06,Spin inversion devices with Fano anti-resonances,"Analyzing spin transport of quasi-2D electrons gas moving through a
semiconductor wave guide subject to a sectionally homogeneous tilted magnetic
field, we found well-defined selection rules for resonant and antiresonant spin
carrier transmission. Based on these selection rules and the band shift induced
by the magnetic field strength and the tilting angles, we propose an efficient
spin inversion device. For a polarized incoming electron beam, we can determine
from our theoretical approach, physical conditions for spin-inversion
efficiency up to 80%. We visualize this mechanism in terms of conductance and
the spacial behavior of the wave function amplitude along the superlattice.",0803.0993v2
2020-11-13,Non-symmetric spin-pumping in a multiferroic heterostructure,"We present spin pumping experiments in Co/Pt bilayers grown on Al2O3(0001)
and on ferroelectric Y-cut LiNbO3 substrates. Spin pumping is triggered by
resonant ferromagnetic resonance induced by surface acoustic waves. We observe
that spin pumping efficiency varies when both the magnetization vector and the
acoustic wave vector are reversed in Pt/Co/LiNbO3. This phenomenon is not
observed in Pt/Co/Al2O3. We propose that the in-plane electric polarization of
LiNbO3 is at the origin of the observed phenomenon. These observations open up
the perspective of an electric field control of spin pumping efficiency.",2011.06872v1
2002-06-05,A mass formula for baryon resonances,"Light-baryon resonances with u,d, and s quarks only can be classified using
the non-relativistic quark model. When we assign to baryon resonances with
total angular momenta J intrinsic orbital angular momenta L and spin S we make
the following observations: plotting the squared masses of the light-baryon
resonances against these intrinsic orbital angular momenta L, Delta's with even
and odd parity can be described by the same Regge trajectory. For a given L,
nucleon resonances with spin S=3/2 are approximately degenerate in mass with
Delta resonances of same total orbital momentum L. To which total angular
momentum L and S couple has no significant impact on the baryon mass. Nucleons
with spin 1/2 are shifted in mass; the shift is - in units of squared masses -
proportional to the component in the wave function which is antisymmetric in
spin and flavor. Sequential resonances in the same partial wave are separated
in mass square by the same spacing as observed in orbital angular momentum
excitations. Based on these observations, a new baryon mass formula is proposed
which reproduces nearly all known baryon masses.",0206012v1
2016-02-02,Magnetization Dynamics of Topological Defects and the Spin Solid in Kagome Artificial Spin Ice,"We report broadband spin-wave spectroscopy on kagome artificial spin ice
(ASI) made of large arrays of interconnected Ni$_{80}$Fe$_{20}$ nanobars.
Spectra taken in saturated and disordered states exhibit a series of resonances
with characteristic magnetic field dependencies. Making use of micromagnetic
simulations, we identify resonances that reflect the spin-solid-state and
monopole-antimonopole pairs on Dirac strings. The latter resonances allow for
the generation of highly-charged vertices in ASIs via microwave assisted
switching. Our findings open further perspectives for fundamental studies on
ASIs and their usage in reprogrammable magnonics.",1602.00918v1
2019-10-16,Ultra-high frequency magnetic resonance through strain-spin coupling in perpendicular magnetic multi-layers,"The interaction between strain and spin has received intensive attention in
the scientific community due to its abundant physical phenomena and huge
technological impact. Until now, there is no experimental report on ultra-high
frequency magnetic resonance through the strain-spin coupling for any
technologically relevant perpendicular magnetic material. Here we report the
experimental detection of the acoustic strain waves that have a response time
on the order of 10 picoseconds in perpendicular magnetic [Co/Pd]n multilayers
via a femtosecond laser pulse excitation. Through direct measurements of
acoustic strain waves, we observe an ultra-high frequency magnetic resonance up
to 60 GHz in [Co/Pd]n multilayers. We further report a theoretical model of the
strain-spin interaction. Our model reveals that the energy could be transferred
efficiently from the strain to the spins and well explains the existence of a
steady resonance state through exciting the spin system. The physical origins
of the resonance between strain waves and magnetic precession and the requested
conditions for obtaining magnetic resonance within thin magnetic films have
also been discussed after thorough analysis. These combined results point out a
potential pathway to enable an extremely high frequency (EHF) magnetic
resonance through the strain-spin coupling.",1910.07147v2
2020-05-02,Anisotropic Spin-Acoustic Resonance in Silicon Carbide at Room Temperature,"We report on acoustically driven spin resonances in atomic-scale centers in
silicon carbide at room temperature. Specifically, we use a surface acoustic
wave cavity to selectively address spin transitions with magnetic quantum
number differences of $\pm$1 and $\pm$2 in the absence of external microwave
electromagnetic fields. These spin-acoustic resonances reveal a non-trivial
dependence on the static magnetic field orientation, which is attributed to the
intrinsic symmetry of the acoustic fields combined with the peculiar properties
of a half-integer spin system. We develop a microscopic model of the
spin-acoustic interaction, which describes our experimental data without
fitting parameters. Furthermore, we predict that traveling surface waves lead
to a chiral spin-acoustic resonance, which changes upon magnetic field
inversion. These results establish silicon carbide as a highly-promising hybrid
platform for on-chip spin-optomechanical quantum control enabling engineered
interactions at room temperature.",2005.00787v1
2015-12-30,Magnetization dynamics and spin pumping induced by standing elastic waves,"The magnetization dynamics induced by standing elastic waves excited in a
thin ferromagnetic film is described with the aid of micromagnetic simulations
taking into account the magnetoelastic coupling between spins and lattice
strains. The simulations have been performed for the 2 nm thick Fe81Ga19 film
dynamically strained by longitudinal and transverse standing waves with various
frequencies, which span a wide range around the resonance frequency nu_res of
coherent magnetization precession in unstrained Fe81Ga19 film. It is found that
standing elastic waves give rise to complex local magnetization dynamics and
spatially inhomogeneous dynamic magnetic patterns. The spatio-temporal
distributions of the magnetization oscillations in standing elastic waves have
the form of standing spin waves with the same wavelength. Remarkably, the
amplitude of magnetization precession does not go to zero at the nodes of these
spin waves, which cannot be precisely described by simple analytical formulae.
In the steady-state regime, the magnetization oscillates with the frequency of
elastic wave, except for the case of longitudinal waves with frequencies well
below nu_res, where the magnetization precesses with a variable frequency
strongly exceeding the wave frequency. The precession amplitude at the
antinodes of standing spin waves strongly increases when the frequency of
elastic wave becomes close to nu_res. The results obtained for the
magnetization dynamics driven by elastic waves are used to calculate the spin
current pumped from the dynamically strained ferromagnet into adjacent
paramagnetic metal. Importantly, the transverse charge current created by the
spin current via the inverse spin Hall effect is high enough to be measured
experimentally.",1512.09051v1
2020-06-15,Femtosecond laser pulse driven caustic spin wave beams,"Controlling the directionality of spin waves is a key ingredient in
wave-based computing methods such as magnonics. In this paper, we demonstrate
this particular aspect by using an all-optical point-like source of continuous
spin waves based on frequency comb rapid demagnetization. The emitted spin
waves contain a range of k-vectors and by detuning the applied magnetic field
slightly off the ferromagnetic resonance (FMR), we observe X-shaped caustic
spin-wave patterns at $70^{\circ}$ propagation angles as predicted by theory.
When the harmonic of the light source approaches theFMR, the caustic pattern
gives way to uniaxial spin-wave propagation perpendicular to the in-plane
component of the applied field. This field-controlled propagation pattern and
directionality of optically emitted short-wavelength spin waves provide
additional degrees of freedom when designing magnonic devices.",2006.08219v1
2010-09-15,Spin-wave interference patterns created by spin-torque nano-oscillators for memory and computation,"Magnetization dynamics in nanomagnets has attracted broad interest since it
was predicted that a dc-current flowing through a thin magnetic layer can
create spin-wave excitations. These excitations are due to spin-momentum
transfer, a transfer of spin angular momentum between conduction electrons and
the background magnetization, that enables new types of information processing.
Here we show how arrays of spin-torque nano-oscillators (STNO) can create
propagating spin-wave interference patterns of use for memory and computation.
Memristic transponders distributed on the thin film respond to threshold tunnel
magnetoresistance (TMR) values thereby detecting the spin-waves and creating
new excitation patterns. We show how groups of transponders create resonant
(reverberating) spin-wave interference patterns that may be used for
polychronous wave computation of arithmetic and boolean functions and
information storage.",1009.4116v1
2020-01-16,Evidence of standing spin-waves in a van der Waals magnetic material,"Spin-waves have been studied for data storage, communication and logic
circuits in the field of spintronics based on their potential to substitute
electrons. Recent discovery of magnetism in two-dimensional (2D) systems such
as monolayer CrI$_3$ and Cr$_2$Ge$_2$Te$_6$ has led to a renewed interest in
such applications of magnetism in the 2D limit. Here we present direct evidence
of standing spin-waves along with the uniform precessional resonance modes in
van der Waals magnetic material, CrCl$_3$. Our experiment is the first direct
observation of standing spin-wave modes, set up across a thickness of 20
$\mu$m, in a van der Waals material. We detect standing spin-waves in the
vicinity of both, optical and acoustic, branches of the antiferromagnetic
resonance. We also observe magnon-magnon coupling, softening of resonance modes
with temperature and extract the evolution of interlayer exchange field as a
function of temperature.",2001.05981v1
2021-06-20,Parametric generation of spin waves in nano-scaled magnonic conduits,"The research feld of magnonics proposes a low-energy wave-logic computation
technology based on spin waves to complement the established CMOS technology
and provide a basis for emerging unconventional computation architectures.
However, magnetic damping is a limiting factor for all-magnonic logic circuits
and multi-device networks, ultimately rendering mechanisms to effciently
manipulate and amplify spin waves a necessity. In this regard, parallel pumping
is a versatile tool since it allows to selectively generate and amplify spin
waves. While extensively studied in microscopic systems, nano-scaled systems
are lacking investigation to assess the feasibility and potential future use of
parallel pumping in magnonics. Here, we investigate a longitudinally magnetized
100 nm-wide magnonic nano-conduit using space and time-resolved micro-focused
Brillouin-light-scattering spectroscopy. Employing parallel pumping to generate
spin waves, we observe that the non-resonant excitation of dipolar spin waves
is favored over the resonant excitation of short wavelength exchange spin
waves. In addition, we utilize this technique to access the effective spin-wave
relaxation time of an individual nano-conduit, observing a large relaxation
time up to (115.0 +- 7.6) ns. Despite the significant decrease of the pumping
effciency in the investigated nano-conduit, a reasonably small threshold is
found rendering parallel pumping feasible on the nano-scale.",2106.10727v2
2007-01-29,"Magnetic Anisotropy, Spin Pinning and Exchange Constants of (Ga,Mn)As films","We present a detailed investigation of exchange-dominated nonpropagating
spin-wave modes in a series of 100 nm Ga$_{1 - x}$Mn$_{x}$As films with Mn
concentrations $x$ ranging from 0.02 to 0.08. The angular and Mn concentration
dependences of spin wave resonance modes have been studied for both as-grown
and annealed samples. Our results indicate that the magnetic anisotropy terms
of Ga$_{1 - x}$Mn$_{x}$As depend on the Mn concentration $x$, but are also
strongly affected by sample growth conditions; moreover, the magnetic
anisotropy of Ga$_{1 - x}$Mn$_{x}$As films is found to be clearly linked to the
Curie temperature. The spin wave resonance spectra consist of a series of well
resolved standing spin-wave modes. The observed mode patterns are consistent
with the Portis volume-inhomogeneity model, in which a spatially nonuniform
anisotropy field acts on the Mn spins. The analysis of these exchange-dominated
spin wave modes, including their angular dependences, allows us to establish
the exchange stiffness constants for Ga$_{1 - x}$Mn$_{x}$As films.",0701717v1
2023-02-10,Ponderomotive force due to the intrinsic spin for electrostatic waves in a magnetized plasma,"We study the contribution from the electron spin to the ponderomotive force,
using a quantum kinetic model including the spin-orbit correction.
Specifically, we derive an analytical expression for the ponderomotive force,
applicable for electrostatic waves propagating parallel to an external magnetic
field. To evaluate the expression, we focus on the case of Langmuir waves and
on the case of the spin-resonance wave mode, where the classical and spin
contributions to the ponderomotive force are compared. Somewhat surprisingly,
dependent on the parameter regime, we find that the spin contribution to the
ponderomotive force may dominate for the Langmuir wave, whereas the classical
contribution can dominate for the spin resonance mode. Naturally, this does not
prevent the opposite case from being the more common one.",2302.05136v1
2021-07-21,Spin-wave growth via Shapiro resonances in a spinor Bose-Einstein condensate,"We theoretically study the resonant phenomenon in a spin-1 Bose-Einstein
condensate periodically driven by a quadratic Zeeman coupling. This phenomenon
is closely related to the Shapiro steps in superconducting Josephson junctions,
and the previous experimental work [Evrard $et al.,$ Phys. Rev. A 100, 023604
(2019)] for a spin-1 bosonic system observed the resonant dynamics and then
called it Shapiro resonance. In this work, using the spin-1 Gross-Pitaevskii
equation, we study the Shapiro resonance beyond the single-mode approximation
used in the previous work, which assumes that all components of the spinor
wavefunction have the same spatial configuration. Considering resonant dynamics
starting from a polar state, we analytically calculate the Floquet-Lyapunov
exponents featuring an onset of the resonance under a linear analysis and find
that spin waves with finite wavenumbers can be excited. This kind of
non-uniform excitation cannot be described by the single-mode approximation.
Furthermore, to study the long-time resonant dynamics beyond the linear
analysis, we numerically solve the one-dimensional spin-1 Gross-Pitaevskii
equation, finding that the nonresonant hydrodynamic variables also grow at
wavelengths of even multiples of the resonant one due to the nonlinear effect.",2107.09924v1
2014-01-16,Odd and Even Partial Waves of ηπ^- and η'π^- in 191 GeV/c π^-p,"In the year 2008 COMPASS recorded diffractive events of the signature
\pi^-(191 GeV) p --> X_fast p. We present results of the analysis of the
subsystems X = \eta(')\pi^-. Besides the known resonances a_2(1320), a_4(2040),
we study the properties of the spin-exotic P+ wave, and all other
natural-exchange partial waves up to spin J = 6. We find a striking difference
between the two final states: whereas the even partial waves J = 2, 4, 6 in the
two systems are related by phase-space factors, the odd partial waves are
relatively suppressed in the \eta\pi^- system. The relative phases between the
even waves appear identical whereas the phase between the D and P waves behave
quite differently, suggesting different resonant and non-resonant contributions
in the two odd-angular-momentum systems. Branching ratios and parameters of the
well-known resonances a_2 and a_4 are measured.",1401.4067v1
2013-10-07,Simulations of electric-dipole spin resonance for spin-orbit-coupled quantum dots in Overhauser field: fractional resonances and selection rules,"We consider spin rotations in single- and two-electron quantum dots that are
driven by external AC electric field with two mechanisms that couple the
electron spatial motion and the spin degree of freedom: the spin-orbit
interaction and a random fluctuation of the Overhauser field due to nuclear
spin bath. We perform a systematic numerical simulation of the driven system
using a finite difference approach with an exact account taken for the
electron-electron correlation. The simulation demonstrates that the electron
oscillation in fluctuating nuclear field is translated into an effective
magnetic field during the electron wave packet motion. The effective magnetic
field drives the spin transitions according to the electric-dipole spin
resonance mechanism. We find distinct signatures of selection rules for direct
and higher-order transitions in terms of the spin-orbital symmetries of the
wave functions. The selection rules are violated by the random fluctuation of
the Overhauser field.",1310.1689v1
2020-07-17,A nonlinear magnonic nano-ring resonator,"The field of magnonics, which aims at using spin waves as carriers in data
processing devices, has attracted increasing interest in recent years. We
present and study micromagnetically a nonlinear nanoscale magnonic ring
resonator device for enabling implementations of magnonic logic gates and
neuromorphic magnonic circuits. In the linear regime, this device efficiently
suppresses spin-wave transmission using the phenomenon of critical resonant
coupling, thus exhibiting the behavior of a notch filter. By increasing the
spin-wave input power, the resonance frequency is shifted leading to
transmission curves, depending on the frequency, reminiscent of the activation
functions of neurons or showing the characteristics of a power limiter. An
analytical theory is developed to describe the transmission curve of magnonic
ring resonators in the linear and nonlinear regimes and validated by a
comprehensive micromagnetic study. The proposed magnonic ring resonator
provides a multi-functional nonlinear building block for unconventional
magnonic circuits.",2007.09205v2
2005-02-07,The resonating valence bond wave functions in quantum antiferromagnets,"Projected-BCS wave functions have been proposed as the paradigm for the
understanding of disordered spin states (spin liquids). Here we investigate the
properties of these wave functions showing how Luttinger liquids, dimerized
states, and gapped spin liquids may be described by the same class of wave
functions, which, therefore, represent an extremely flexible variational tool.
A close connection between spin liquids and",0502170v1
2009-08-14,Spin-wave interference in three-dimensional rolled-up ferromagnetic microtubes,"We have investigated spin-wave excitations in rolled-up Permalloy microtubes
using microwave absorption spectroscopy. We find a series of quantized
azimuthal modes which arise from the constructive interference of Damon-Eshbach
type spin waves propagating around the circumference of the microtubes, forming
a spin-wave resonator. The mode spectrum can be tailored by the tube's radius
and number of rolled-up layers.",0908.2082v1
2017-08-26,Subwavelength and directional control of flexural waves in zone-folding induced topological plates,"Inspired by the quantum spin Hall effect shown by topological insulators, we
propose a plate structure that can be used to demonstrate the pseudo-spin Hall
effect for flexural waves. The system consists of a thin plate with
periodically arranged resonators mounted on its top surface. We extend a
technique based on the plane wave expansion method to identify a double Dirac
cone emerging due to the zone-folding in frequency band structures. This
particular design allows us to move the double Dirac cone to a lower frequency
than the resonating frequency of local resonators. We then manipulate the
pattern of local resonators to open subwavelength Bragg band gaps that are
topologically distinct. Building on this method, we verify numerically that a
waveguide at an interface between two topologically distinct resonating plate
structures can be used for guiding low-frequency, spin-dependent one-way
flexural waves along a desired path with bends.",1708.07994v2
1998-12-02,Theory of Orbital Excitation and Resonant Inelastic X-ray Scattering in Manganites,"We study theoretically the collective orbital excitation named orbital wave
in the orbital ordered manganites.The dispersion relation of the orbital wave
is affected by the static spin structure through the coupling between spin and
orbital degrees of freedom. As a probe to detect the dispersion relation, we
propose two possible methods by utilizing resonant inelastic x-ray scattering.
The transition probability of the orbital wave scattering is formulated, and
the momentum and polarization dependences of the structure factor are
calculated in several types of the orbital and spin structures. The elastic
x-ray scattering in the L-edge case to observe the orbital ordering is also
discussed.",9812028v1
2005-03-08,The temperature dependence of interlayer exchange coupling - spin waves vs. spacer effects,"There are different mechanisms proposed to be responsible for the temperature
dependence of the interlayer exchange coupling (IEC), namely a smearing out of
the spacer or interface Fermi surface and excitations and interactions of spin
waves. We propose a possibility to separate both effects by calculating the
excitation spectrum of an extended Heisenberg model and connecting the results
with ferromagnetic resonance (FMR) experiments. To solve the Heisenberg model
we use an approximation that was shown to yield excellent results. In this
paper the main idea of this procedure is explained and a detailed investigation
of the spin wave contribution to the temperature dependence of FMR resonance
frequencies and fields is carried out.",0503178v1
2001-07-10,Resonating Valence Bond Wave Functions for Strongly Frustrated Spin Systems,"The Resonating Valence Bond (RVB) theory for two-dimensional quantum
antiferromagnets is shown to be the correct paradigm for large enough ``quantum
frustration''. This scenario, proposed long time ago but never confirmed by
microscopic calculations, is very strongly supported by a new type of
variational wave function, which is extremely close to the exact ground state
of the $J_1{-}J_2$ Heisenberg model for $0.4 \lesssim J_2/J_1\lesssim 0.5$.
This wave function is proposed to represent the generic spin-half RVB ground
state in spin liquids.",0107204v1
2008-10-22,Probing of a parametrically pumped magnon gas with a non-resonant packet of traveling spin waves,"The magnon gas created by spatially localized longitudinal parametric pumping
in an yttrium-iron-garnet film is probed by a traveling packet of spin waves
non-resonant with the pumping field. The analysis of the influence of the
magnon gas on the amplitude and phase of the propagating spin waves allows to
determine characteristic properties of the parametrically pumped magnon gas. A
simple theoretical model is proposed from which the magnon density in the
pumping region is calculated.",0810.4033v1
2016-10-19,Resonant Magnetization Switching Conditions of an Exchange-coupled Bilayer under Spin Wave Excitation,"We systematically investigated the spin wave-assisted magnetization switching
(SWAS) of a L10-FePt / Ni81Fe19 (Permalloy; Py) exchange-coupled bilayer using
a pulse-like rf field (hrf) and mapped the switching events in the magnetic
field (H) - hrf frequency (f) plane to reveal the switching conditions. The
switching occurred only in a limited region following the dispersion
relationship of the perpendicular standing spin wave (PSSW) modes in Py. The
results indicate that SWAS is a resonant magnetization switching process, which
is different from the conventional microwave assisted switching, and has the
potential to be applied to selective switching for multilevel recording media.",1610.05864v1
2018-06-04,An analog magnon adder for all-magnonic neurons,"Spin-waves are excellent data carriers with a perspective use in neuronal
networks: Their lifetime gives the spin-wave system an intrinsic memory, they
feature strong nonlinearity, and they can be guided and steered through
extended magnonic networks. In this work, we present a magnon adder that
integrates over incoming spin-wave pulses in an analog fashion. Such an adder
is a linear prequel to a magnonic neuron, which would integrate over the
incoming pulses until a certain nonlinearity is reached. In this work, the
adder is realized by a resonator in combination with a parametric amplifier
which is just compensating the resonator losses.",1806.01389v1
2018-04-27,Angular Dependent Magnetization Dynamics with Mirror-symmetric Excitations in Artificial Quasicrystalline Nanomagnet Lattices,"We report angle-dependent spin-wave spectroscopy on aperiodic
quasicrystalline magnetic lattices, i.e., Ammann, Penrose P2 and P3 lattices
made of large arrays of interconnected Ni$_{80}$Fe$_{20}$ nanobars. Spin-wave
spectra obtained in the nearly saturated state contain distinct sets of
resonances with characteristic angular dependencies for applied in-plane
magnetic fields. Micromagnetic simulations allow us to attribute detected
resonances to mode profiles with specific mirror symmetries. Spectra in the
reversal regime show systematic emergence and disappearance of spin wave modes
indicating reprogrammable magnonic characteristics.",1804.10630v1
2014-04-08,Resonant Spin Wave Excitation by Terahertz Magnetic Near-field Enhanced with Split Ring Resonator,"Excitation of antiferromagnetic spin waves in HoFeO$_{3}$ crystal combined
with a split ring resonator (SRR) is studied using terahertz (THz)
electromagnetic pulses. The magnetic field in the vicinity of the SRR induced
by the incident THz electric field component excites and the Faraday rotation
of the polarization of a near-infrared probe pulse directly measures
oscillations that correspond to the antiferromagnetic spin resonance mode. The
good agreement of the temperature-dependent magnetization dynamics with the
calculation using the two-lattice Landau-Lifshitz-Gilbert equation confirms
that the spin wave is resonantly excited by the THz magnetic near-field
enhanced at the LC resonance frequency of the SRR, which is 20 times stronger
than the incident magnetic field.",1404.2179v1
2011-10-06,Spin pumping with coherent elastic waves,"We show that the resonant coupling of phonons and magnons can be exploited to
generate spin currents at room temperature. Surface acoustic wave (SAW) pulses
with a frequency of 1.55 GHz and duration of 300 ns provide coherent elastic
waves in a ferromagnetic thin film/normal metal (Co/Pt) bilayer. We use the
inverse spin Hall voltage in the Pt as a measure for the spin current and
record its evolution as a function of time and external magnetic field
magnitude and orientation. Our experiments show that a spin current is
generated in the exclusive presence of a resonant elastic excitation. This
establishes acoustic spin pumping as a resonant analogue to the spin Seebeck
effect.",1110.1187v2
2021-02-24,Spin waves and high-frequency response in layered superconductors with helical magnetic structure,"We evaluate the spin-wave spectrum and dynamic susceptibility in a layered
superconductors with helical interlayer magnetic structure. We especially focus
on the structure in which the moments rotate 90$^{\circ}$ from layer to layer
realized in the iron pnictide RbEuFe$_{4}$As$_{4}$. The spin-wave spectrum in
superconductors is strongly renormalized due to the long-range electromagnetic
interactions between the oscillating magnetic moments. This leads to strong
enhancement of the frequency of the mode coupled with uniform field and this
enhancement exists only within a narrow range of the c-axis wave vectors of the
order of the inverse London penetration depth. The key feature of materials
like RbEuFe$_{4}$As$_{4}$ is that this uniform mode corresponds to the maximum
frequency of the spin-wave spectrum with respect to c-axis wave vector. As a
consequence, the high-frequency surface resistance acquires a very distinct
asymmetric feature spreading between the bare and renormalized frequencies. We
also consider excitation of spin waves with Josephson effect in a tunneling
contact between helical-magnetic and conventional superconductors and study the
interplay between the spin-wave features and geometrical cavity resonances in
the current-voltage characteristics.",2102.12445v2
2019-01-30,Optimizing propagating spin wave spectroscopy,"The frequency difference between two oppositely propagating spin waves can be
used to probe several interesting magnetic properties, such as the
Dzyaloshinkii-Moriya interaction (DMI). Propagating spin wave spectroscopy is a
technique that is very sensitive to this frequency difference. Here we show
several elements that are important to optimize devices for such a measurement.
We demonstrate that for wide magnetic strips there is a need for de-embedding.
Additionally, for these wide strips there is a large parasitic antenna-antenna
coupling that obfuscates any spin wave transmission signal, which is remedied
by moving to smaller strips. The conventional antenna design excites spin waves
with two different wave vectors. As the magnetic layers become thinner, the
resulting resonances move closer together and become very difficult to
disentangle. In the last part we therefore propose and verify a new antenna
design that excites spin waves with only one wave vector. We suggest to use
this antenna design to measure the DMI in thin magnetic layers.",1901.11108v1
2013-03-05,"Angle-Dependent Spin-Wave Resonance Spectroscopy of (Ga,Mn)As Films","A modeling approach for standing spin-wave resonances based on a
finite-difference formulation of the Landau-Lifshitz-Gilbert equation is
presented. In contrast to a previous study [Bihler et al., Phys. Rev. B 79,
045205 (2009)], this formalism accounts for elliptical magnetization precession
and magnetic properties arbitrarily varying across the layer thickness,
including the magnetic anisotropy parameters, the exchange stiffness, the
Gilbert damping, and the saturation magnetization. To demonstrate the
usefulness of our modeling approach, we experimentally study a set of (Ga,Mn)As
samples grown by low-temperature molecular-beam epitaxy by means of
electrochemical capacitance-voltage measurements and angle-dependent standing
spin-wave resonance spectroscopy. By applying our modeling approach, the angle
dependence of the spin-wave resonance data can be reproduced in a simulation
with one set of simulation parameters for all external field orientations. We
find that the approximately linear gradient in the out-of-plane magnetic
anisotropy is related to a linear gradient in the hole concentrations of the
samples.",1303.1192v1
2020-03-08,The effect of material defects on resonant spin wave modes in a nanomagnet,"We have theoretically studied how resonant spin wave modes in an elliptical
nanomagnet are affected by fabrication defects, such as small local thickness
variations. Our results indicate that defects of this nature, which can easily
result from the fabrication process, or are sometimes deliberately introduced
during the fabrication process, will significantly alter the frequencies,
magnetic field dependence of the frequencies, and the power and phase profiles
of the resonant spin wave modes. They can also spawn new resonant modes and
quench existing ones. All this has important ramifications for multi-device
circuits based on spin waves, such as phase locked oscillators for neuromorphic
computing, where the device-to-device variability caused by defects can be
inhibitory.",2003.03833v1
2021-11-15,Nonstanding spin waves in a single rectangular permalloy microstrip under uniform magnetic excitation,"Ferromagnetic resonance modes in a single rectangular Ni$_{80}$Fe$_{20}$
microstrip were directly imaged using time-resolved scanning transmission x-ray
microscopy combined with a phase-locked ferromagnetic resonance excitation
scheme and the findings were corroborated by micromagnetic simulations.
Although under uniform excitation in a single confined microstructure typically
standing spin waves are expected, all imaged spin waves showed a nonstanding
character both, at and off resonance, the latter being additionally detected
with microantenna-based ferromagnetic resonance. The effect of the edge quality
on the spin waves was observed in micromagnetic simulations.",2111.07773v3
2013-12-01,Probing evolution of binaries influenced by the spin-orbit resonances,"We evolve isolated comparable mass spinning compact binaries experiencing
Schnittman's post-Newtonian spin-orbit resonances in an inertial frame
associated with $j_0$, the initial direction of the total angular momentum. We
argue that accurate gravitational wave (GW) measurements of the initial
orientations of the two spins and orbital angular momentum from $j_0$ should
allow us to distinguish between the two possible families of spin-orbit
resonances. Therefore, these measurements have the potential to provide direct
observational evidence of possible binary formation scenarios. The above
statements should also apply for binaries that do not remain in a resonant
plane when they become detectable by GW interferometers. The resonant plane,
characterized by the vanishing scalar triple product involving the two spins
and the orbital angular momentum, naturally appears in the one parameter family
of equilibrium solutions, discovered by Schnittman. We develop a prescription
to compute the time-domain inspiral templates for binaries residing in these
resonant configurations and explore their preliminary data analysis
consequences.",1312.0217v2
2019-02-20,Green's function method for the spin and pseudospin symmetries in the single-particle resonant states,"We investigate the spin and pseudospin symmetry in the single-particle
resonant states by solving the Dirac equation containing a Woods-Saxon
potential with Green's function method. Taking double-magic nucleus $^{208}$Pb
as an example, three spin doublets $3d$, $2h$, and $1j$ and three pseudospin
doublets $3\tilde{p}$, $1\tilde{i}$, and $1\tilde{j}$ are obtained for the
single-neutron resonant states. By analyzing the energy splittings, we find
that the threshold effect plays an important role in resonant pseudospin
doubles. Besides, there is a reversed level structure of pseudospin doublets in
the continuum. Differently, all the width splittings of either the spin
doublets or the pseudospin doublets are systematically positive and the
splittings are very small except $1\tilde{j}$ doublet. Further studies show
that the splittings of the energies and widths for the resonant (pseudo)spin
doublets are independent. Besides, the similarity properties of the wave
functions of the spin and pseudospin doublets still maintain well in resonant
states.",1902.07442v1
2020-08-07,Spin wave excitations in exchange biased IrMn/CoFe bilayers,"Using an atomistic spin model, we have simulated spin wave injection and
propagation into antiferromagnetic IrMn from an exchange coupled CoFe layer.
The spectral characteristics of the exited spin waves have a complex beating
behavior arising from the non-collinear nature of the antiferromagnetic order.
We find that the frequency response of the system depends strongly on the
strength and frequency of oscillating field excitations. We also find that the
strength of excited spin waves strongly decays away from the interfacial layer
with a frequency dependent attenuation. Our findings suggest that spin waves
generated by coupled ferromagnets are too weak to reverse IrMn in their
entirety even with resonant excitation of a coupled ferromagnet. However,
efficient spin wave injection into the antiferromagnet is possible due to the
non-collinear nature of the IrMn spin ordering.",2008.03036v1
2007-10-11,Direct current voltage induced by microwave signal in a ferromagnetic wire,"Experimental results of rectification of a constant wave radio frequency (RF)
current flowing in a single-layered ferromagnetic wire are presented. We show
that a detailed external magnetic field dependence of the RF current induced a
direct-current voltage spectrum. The mechanism of the rectification is
discussed in a term of the spin transfer torque, and the rectification is
closely related to resonant spin wave excitation with the assistant of the
spin-polarized RF current. The micromagnetic simulation taking into account the
spin transfer torque provides strong evidence which supports the generation of
spin wave excitation by the RF current.",0710.2172v1
2012-11-27,Short range asymptotic behavior of the wave-functions of interacting spin-half fermionic atoms with spin-orbit coupling: a model study,"We consider spin-half fermionic atoms with isotropic Rashba spin-orbit
coupling in three directions. The interatomic potential is modeled by a square
well potential. We derive the analytic form of the asymptotic wave-functions at
short range of two fermions in the subspace of zero net momentum and zero total
angular momentum. We show that the spin-orbit coupling has perturbative effects
on the short range asymptotic behavior of the wave-functions away from
resonances. We argue that our conclusion should hold generally.",1211.6221v2
2009-05-21,Creating traveling waves from standing waves from the gyrotropic paramagnetic properties of Fe$^{3+}$ ions in a high-Q whispering gallery mode sapphire resonator,"We report observations of the gyrotropic change in magnetic susceptibility of
the Fe$^{3+}$ electron paramagnetic resonance at 12.037GHz (between spin states
$|1/2>$ and $|3/2>$) in sapphire with respect to applied magnetic field.
Measurements were made by observing the response of the high-Q Whispering
Gallery doublet (WGH$_{\pm17,0,0}$) in a Hemex sapphire resonator cooled to 5
K. The doublets initially existed as standing waves at zero field and were
transformed to traveling waves due to the gyrotropic response.",0905.3435v1
2015-06-17,Continuous wave approach for simulating Ferromagnetic Resonance in nanosized elements,"We present a numerical approach to simulate the Ferromagnetic Resonance (FMR)
of micron and nanosized magnetic elements by a micromagnetic finite difference
method. In addition to a static magnetic field a linearly polarized oscillating
magnetic field is utilized to excite and analyze the spin wave excitations
observed by Ferromagnetic Resonance in the space- and time-domain. Our
continuous wave approach (CW) provides an alternative to the common simulation
method, which uses a pulsed excitation of the magnetic system. It directly
models conventional FMR-experiments and permits the determination of the real
and imaginary part of the complex dynamic susceptibility without the need of
post-processing. Furthermore not only the resonance fields, but also
linewidths, ellipticity, phase relations and relative intensities of the
excited spin wave modes in a spectrum can be determined and compared to
experimental data. The magnetic responses can be plotted as a function of
spatial dimensions yielding a detailed visualization of the spin wave modes and
their localization as a function of external magnetic field and frequency. This
is illustrated for the case of a magnetic micron sized stripe.",1506.05292v1
2018-03-05,Theory of magnetoelastic resonance in a mono-axial chiral helimagnet,"We study magnetoelastic resonance phenomena in a mono-axial chiral helimagnet
belonging to hexagonal crystal class. By computing the spectrum of coupled
elastic wave and spin wave, it is demonstrated how hybridization occurs
depending on their chirality. Specific features of the magnetoelastic resonance
are discussed for the conical phase and the soliton lattice phase stabilized in
the mono-axial chiral helimagnet. The former phase exhibits appreciable
non-reciprocity of the spectrum, the latter is characterized by a
multi-resonance behavior. We propose that the non-reciprocal spin wave around
the forced-ferromagnetic state has potential capability to convert the linearly
polarized elastic wave to circularly polarized one with the chirality opposite
to the spin wave chirality.",1803.01691v2
2023-11-09,Skyrmion-Excited Spin Wave Fractal Network,"Magnetic skyrmions exhibit unique, technologically relevant pseudo-particle
behaviors which arise from their topological protection, including
well-defined, three-dimensional dynamic modes that occur at microwave
frequencies. During dynamic excitation, spin waves are ejected into the
interstitial regions between skyrmions, creating the magnetic equivalent of a
turbulent sea. However, since the spin waves in these systems have a
well-defined length scale, and the skyrmions are on an ordered lattice, ordered
structures from spin wave interference can precipitate from the chaos. This
work uses small angle neutron scattering (SANS) to capture the dynamics in
hybrid skyrmions and investigate the spin wave structure. Performing
simultaneous ferromagnetic resonance and SANS, the diffraction pattern shows a
large increase in low-angle scattering intensity which is present only in the
resonance condition. This scattering pattern is best fit using a mass fractal
model, which suggests the spin waves form a long-range fractal network. The
fractal structure is constructed of fundamental units with a size that encodes
the spin wave emissions and are constrained by the skyrmion lattice. These
results offer critical insights into the nanoscale dynamics of skyrmions,
identify a new dynamic spin wave fractal structure, and demonstrates SANS as a
unique tool to probe high-speed dynamics.",2311.05469v1
2021-09-22,Hopfion Dynamics in Chiral Magnets,"Resonant spin dynamics of topological spin textures are correlated with their
topological nature, which can be employed to understand this nature. In this
study, we present resonant spin dynamics of three-dimensional topological spin
texture, i.e., Neel and Bloch hopfions. Using micromagnetic simulations, we
stabilize Bloch and Neel hopfions with bulk and interfacial
Dzyaloshinskii-Moriya interaction (DMI), respectively. We identify the ground
state spin configuration of both hopfions, effects of anisotropies, geometric
confinements, and demagnetizing fields. To confirm topological nature, Hopf
number is calculated for each spin texture. Then, we calculate the resonance
frequencies and spin-wave modes of spin precessions under multiple magnetic
fields. Unique resonance frequencies and specific magnetic field dependence can
help to guide experimental studies to identify the three-dimensional
topological spin texture of hopfions in functioning chiral magnets when imaging
is not possible.",2109.10758v1
2020-01-15,Yttrium Iron Garnet Thickness Influence on the Spin Pumping in the Bulk Acoustic Wave Resonator,"The features of phonon-magnon interconversion in acoustic resonator determine
the efficiency of spin pumping from YIG into Pt that may be detected
electrically through the inverse spin Hall effect (ISHE). Based on the methods
developed in previous works for calculating resonator structures with a
piezoelectric (ZnO) and a magnetoelastic layer in contact with the heavy metal
(YIG/Pt), we present the results of numerical calculations of YIG film
thickness influence on acoustically driven spin waves. We obtain some YIG film
thickness regions with various behavior of dc ISHE voltage $U_{ISHE}$. At
micron and submicron thicknesses, the higher spin wave resonance (SWR) modes
(both even and odd) can be generated with efficiency comparable and even
exceeding that of the main mode. The absolute maximum of $U_{ISHE}$ is achieved
at the thickness about $s_1 \approx 208$ nm under the excitation of the first
SWR.",2001.05385v1
2024-02-29,Resonant generation of propagating second-harmonic spin waves in nano-waveguides,"Generation of second-harmonic waves is one of the universal nonlinear
phenomena that have found numerous technical applications in many modern
technologies, in particular, in photonics. This phenomenon also has great
potential in the field of magnonics, which considers the use of spin waves in
magnetic nanostructures to implement wave-based signal processing and
computing. However, due to the strong frequency dependence of the phase
velocity of spin waves, resonant phase-matched generation of second-harmonic
spin waves has not yet been achieved in practice. Here, we show experimentally
that such a process can be realized using a combination of different modes of
nano-sized spin-wave waveguides based on low-damping magnetic insulators. We
demonstrate that our approach enables efficient spatially-extended energy
transfer between interacting waves, which can be controlled by the intensity of
the initial wave and the static magnetic field. The demonstrated approach can
be used for the generation of short-wavelength spin waves that are difficult to
excite directly, as well as for the implementation of novel devices for
magnonic logic and unconventional computing.",2402.18964v1
2010-08-21,Dynamical Corrections to Spin Wave Excitations in Quantum Wells due to Coulomb Interactions and Magnetic Ions,"We have measured dispersions of spin-flip waves and spin-flip single-particle
excitations of a spin polarized two-dimensional electron gas in a CdMnTe
quantum well using resonant Raman scattering. We find the energy of the
spin-flip wave to be below the spin-flip single particle excitation continuum,
a contradiction to the theory of spin waves in diluted magnetic semiconductors
put forth in [Phys. Rev. B 70, 045205 (2004)]. We show that the inclusion of
terms accounting for the Coulomb interaction between carriers in the spin wave
propagator leads to an agreement with our experimental results. The dominant
Coulomb contribution leads to an overall red shift of the mixed electron-Mn
spin modes while the dynamical coupling between Mn ions results in a small blue
shift. We provide a simulated model system which shows the reverse situation
but at an extremely large magnetic field.",1008.3663v1
2015-10-09,Single-electron Spin Resonance in a Quadruple Quantum Dot,"Electron spins in semiconductor quantum dots are good candidates of quantum
bits for quantum information processing. Basic operations of the qubit have
been realized in recent years: initialization, manipulation of single spins,
two qubit entanglement operations, and readout. Now it becomes crucial to
demonstrate scalability of this architecture by conducting spin operations on a
scaled up system. Here, we demonstrate single-electron spin resonance in a
quadruple quantum dot. A few-electron quadruple quantum dot is formed within a
magnetic field gradient created by a micro-magnet. We oscillate the wave
functions of the electrons in the quantum dots by applying microwave voltages
and this induces electron spin resonance. The resonance energies of the four
quantum dots are slightly different because of the stray field created by the
micro-magnet and therefore frequency-resolved addressable control of the
electron spin resonance is possible.",1510.02547v1
2020-07-30,Resonant subwavelength control of the phase of spin waves reflected from a ferromagnetic film edge,"Using frequency-domain finite element calculations cross-checked with
micromagnetic simulations, we demonstrate that the phase of spin waves
reflected from an interface between a permalloy film and a bilayer can be
controlled by changing dimensions of the bilayer. Treating the bilayer formed
by the permalloy film and a ferromagnetic stripe as a segment of a multi-mode
waveguide, we show that spin-wave Fabry-Perot resonances of one of its modes
are responsible for the high sensitivity of the phase of reflected waves to
stripe width and the stripe-film separation. Thus, the system is a unique
realization of a fully magnonic Gires-Tournois interferometer based on a
two-modes resonator, which can be treated as a magnonic counterpart of a
metasurface, since it enables manipulation of the phase of spin waves at
subwavelength distances. Knowledge gained from these calculations might be used
to design magnonic devices such as flat lenses or magnetic particle detectors.",2007.15226v5
2022-06-23,Valley spin-acoustic resonance in MoS${\bf _2}$ monolayers,"The band structure of a monolayer MoS$_2$ comprises of spin-split subbands,
owing to the mutual presence of broken inversion symmetry and strong spin-orbit
coupling. In the conduction band, spin-valley coupled subbands cross each other
at finite momenta, and they are valley-degenerate. When exposed to surface
acoustic waves, the emerging strain-induced effective magnetic field can give
rise to spin-flip transitions between the spin-split subbands in the vicinity
of subbands crossing point, resulting in the emergence of a spin-acoustic
resonance and the acoustoelectric current. An external magnetic field breaks
the valley degeneracy resulting in the valley-selective splitting of
spin-acoustic resonances both in surface acoustic wave absorption and
acoustoelectric current.",2206.11551v1
2011-12-03,Microwave-induced DC Signal in a Permalloy Thin Strip at Low Applied Magnetic Field,"We investigated the ferromagnetic resonance signals in a polycrystalline
permalloy thin strip under in-plane low static magnetic field. A series of DC
voltages, which contain ferromagnetic resonance or spin wave resonance signals,
were measured by inducing microwave frequencies greater than 10 gigahertz. The
resonant signals measured in low magnetic field show different properties from
those detected in high field condition. Based on the theory of DC effects in
ferromagnetic resonance and the experimental data of anisotropic
magnetoresistance, a quantitative model was proposed. We found that the shape
anisotropy significantly affects magnetization, and distorts the resonant
signals in low field condition.",1112.0610v1
2002-08-13,Spin-Wave Description of Nuclear Spin-Lattice Relaxation in Mn_{12}O_{12} Acetate,"In response to recent nuclear-magnetic-resonance (NMR) measurements on the
molecular cluster Mn_{12}O_{12} acetate, we study the nuclear spin-lattice
relaxation rate 1/T_1 developing a modified spin-wave theory. Our microscopic
new approach, which is distinct from previous macroscopic treatments of the
cluster as a rigid spin of S=10, not only excellently interprets the observed
temperature and applied-field dependences of 1/T_1 for ^{55}Mn nuclei but also
strongly supports the ^{13}C NMR evidence for spin delocalization over the
entire molecule.",0208245v1
2007-06-12,Magnetic fingerprint in a ferromagnetic wire: Spin torque diode effect and induction of the DC voltage spectrum inherent in the wire under application for RF current,"We report the rectifying effect of a constant-wave radio frequency (RF)
current by a magnetic domain wall (DW) on a single-layered ferromagnetic wire.
A direct-current (DC) voltage is generated by the spin torque diode effect,
which is a consequence of magnetoresistance oscillation due to the resonant
spin wave excitation induced by the spin-polarized RF current. The DC voltage
spectrum strongly depends on the internal spin structure in the DW, which
corresponds to the magnetic fingerprint of the spin structure in the
ferromagnetic wire.",0706.1733v1
2017-10-30,Spin-transfer Antiferromagnetic Resonance,"Currents can induce spin excitations in antiferromagnets, even when they are
insulating. We investigate how spin transfer can cause antiferromagnetic
resonance in bilayers and trilayers that consist of one antiferromagnetic
insulator and one or two metals. An ac voltage applied to the metal generates a
spin Hall current that drives the magnetic moments in the antiferromagnet. We
consider excitation of the macrospin mode and of transverse standing-spin-wave
modes. By solving the Landau-Lifshitz-Gilbert equation in the antiferromagnetic
insulator and the spin-diffusion equation in the normal metal, we derive
analytical expressions for the spin-Hall-magnetoresistance and spin-pumping
inverse-spin-Hall dc voltages. In bilayers, the two contributions compensate
each other and cannot easily be distinguished. We present numerical results for
a MnF$_2|$Pt bilayer. Trilayers facilitate separation of the
spin-Hall-magnetoresistance and spin-pumping voltages, thereby revealing more
information about the spin excitations. We also compute the decay of the pumped
spin current through the antiferromagnetic layer as a function of frequency and
the thickness of the antiferromagnetic layer.",1710.10909v1
2016-03-11,Separating hyperfine from spin-orbit interactions in organic semiconductors by multi-octave magnetic resonance using coplanar waveguide microresonators,"Separating the influence of hyperfine from spin-orbit interactions in
spin-dependent carrier recombination and dissociation processes necessitates
magnetic resonance spectroscopy over a wide range of frequencies. We have
designed compact and versatile coplanar waveguide resonators for
continuous-wave electrically detected magnetic resonance, and tested these on
organic light-emitting diodes. By exploiting both the fundamental and
higher-harmonic modes of the resonators we cover almost five octaves in
resonance frequency within a single setup. The measurements with a common
pi-conjugated polymer as the active material reveal small but non-negligible
effects of spin-orbit interactions, which give rise to a broadening of the
magnetic resonance spectrum with increasing frequency.",1603.03807v1
2024-03-13,Dielectric microwave resonator with large optical apertures for spin-based quantum devices,"Towards a spin-based quantum microwave-optical photon transducer, we
demonstrate a low-loss dielectric microwave resonator with an internal quality
factor of $2.30\times10^4$ while accommodating optical apertures with a
diameter of $8\, \mathrm{mm}$. The two seemingly conflicting requirements, high
quality factor and large optical apertures, are satisfied thanks to the large
dielectric constant of rutile ($\mathrm{TiO_2}$). The quality factor is limited
by radiation loss, and we confirmed by numerical simulation that this
dielectric resonator can achieve a quality factor exceeding $10^6$ by extending
the height of the resonator enclosure. Using this resonator, we performed both
continuous-wave (cw) and pulse electron spin resonance (ESR) spectroscopy on
2,2-diphenyl-1-picrylhydrazyl (DPPH) crystalline powder and P1 centers in a
diamond crystal in a dilution refrigerator. The cw ESR spectroscopy
demonstrated high-cooperativity and strong spin-resonator coupling with the
DPPH and P1 centers respectively, while the pulse ESR spectroscopy successfully
measured longitudinal and transverse relaxation times.",2403.08458v1
2022-12-15,Identification of acoustically induced spin resonances of Si vacancy centers in 4H-SiC,"The long-lived and optically addressable spin states of silicon vacancies
($\mathrm{V}_\mathrm{Si}$) in 4H-SiC make them promising qubits for quantum
communication and sensing. These color centers can be created in both the
hexagonal (V1) and in the cubic (V2) local crystallographic environments of the
4H-SiC host. While the spin of the V2 center can be efficiently manipulated by
optically detected magnetic resonance at room temperature, spin control of the
V1 centers above cryogenic temperatures has so far remained elusive. Here, we
show that the dynamic strain of surface acoustic waves can overcome this
limitation and efficiently excite magnetic resonances of V1 centers up to room
temperature. Based on the width and temperature dependence of the acoustically
induced spin resonances of the V1 centers, we attribute them to transitions
between spin sublevels in the excited state. The acoustic spin control of both
kinds of $\mathrm{V}_\mathrm{Si}$ centers in their excited states opens new
ways for applications in quantum technologies based on spin-optomechanics.",2212.07704v2
2013-10-07,Double magnetic resonance and spin anisotropy in Fe-based superconductors due to static and fluctuating antiferromagnetic orders,"Motivated by recent neutron scattering experiments in Fe-based
superconductors, we study how the magnetic resonance in the superconducting
state is affected by the simultaneous presence of either static or fluctuating
magnetic orders using the random phase approximation. We find that for the
underdoped materials with coexisting superconducting and antiferromagnetic
orders, spin rotational symmetry is explicitly broken at the ordering momentum
$Q_1 = (\pi,0)$. Only the longitudinal susceptibility exhibits the resonance
mode, whereas a spin-wave Goldstone mode develops in the transverse component.
Meanwhile, at the frustrated momentum $Q_2 = (0,\pi)$, the susceptibility
becomes isotropic in spin space and the magnetic resonance exists for both
components. Furthermore, the resonance energies at $Q_1$ and $Q_2$ have
distinct scales, which provides a natural explanation for the recently observed
double resonance peaks. In addition, we show that near optimal doping the
existence of strong magnetic fluctuations, which are modeled here via a
Gaussian mode, can still induce the spin anisotropy in the magnetic
susceptibility.",1310.1657v2
2001-07-10,"Parametric Resonance Amplification of Neutrino Oscillations in Electromagnetic Wave with Varying Amplitude and ""Castle Wall"" Magnetic Field","Within the Lorentz invariant formalizm for description of neutrino evolution
in electromagnetic fields and matter we consider neutrino spin oscillations in
the electromagnetic wave with varying amplitude and in ""castle wall"" magnetic
field. It is shown for the first time that the parametric resonances of
neutrino oscillations in such systems can occur.",0107109v1
2016-05-14,Universal One-dimensional Atomic Gases Near Odd-wave Resonance,"We show the renormalization of contact interaction for odd-wave scattering in
one-dimension(1D). Based on the renormalized interaction, we exactly solve the
two-body problem in a harmonic trap, and further explore the universal
properties of spin-polarized fermions near odd-wave resonance using the
operator product expansion method. It is found that the high-momentum
distribution behaves as $C/k^2$, with $C$ the odd-wave contact. Various
universal relations are derived. Our work suggests a new universal system
emergent in 1D with large odd-wave scattering length.",1605.04363v3
2017-04-07,Spin wave propagation and spin polarized electron transport in single crystal iron films,"The technique of propagating spin wave spectroscopy is applied to a 20 nm
thick Fe/MgO (001) film. The magnetic parameters extracted from the position of
the resonance peaks are very close to those tabulated for bulk iron. From the
propagating waveforms, a group velocity of 4 km/s and an attenuation length of
about 6 micrometers are extracted for 1.6 micrometers-wavelength spin-wave at
18 GHz. From the measured current-induced spin-wave Doppler shift, we also
extract a surprisingly high degree of spin-polarization of the current of 83%.
This set of results makes single-crystalline iron a promising candidate for
building devices utilizing high frequency spin-waves and spin-polarized
currents.",1704.02217v1
2003-09-24,Anomalous behavior of spin wave resonances in Ga_{1-x}Mn_{x}As thin films,"We report ferromagnetic and spin wave resonance absorption measurements on
high quality epitaxially grown Ga_{1-x}Mn_{x}As thin films. We find that these
films exhibit robust ferromagnetic long-range order, based on the fact that up
to seven resonances are detected at low temperatures, and the resonance
structure survives to temperatures close to the ferromagnetic transition. On
the other hand, we observe a spin wave dispersion which is linear in mode
number, in qualitative contrast with the quadratic dispersion expected for
homogeneous samples. We perform a detailed numerical analysis of the
experimental data and provide analytical calculations to demonstrate that such
a linear dispersion is incompatible with uniform magnetic parameters. Our
theoretical analysis of the ferromagnetic resonance data, combined with the
knowledge that strain-induced anisotropy is definitely present in these films,
suggests that a spatially dependent magnetic anisotropy is the most likely
reason behind the anomalous behavior observed.",0309566v2
2022-04-26,Hot-lines topology and the fate of the spin resonance mode in three-dimensional unconventional superconductors,"In the quasi-two-dimensional (quasi-2D) copper- and iron-based
superconductors, the onset of superconductivity is accompanied by a prominent
peak in the magnetic spectrum at momenta close to the wave-vector of the nearby
antiferromagnetic state. Such a peak is well described in terms of a spin
resonance mode, i.e., a spin-1 exciton theoretically predicted for quasi-2D
superconductors with a sign-changing gap. The same theories, however, indicate
that such a resonance mode should be absent in a three-dimensional (3D) system
with a spherical Fermi surface. This raises the question of the fate of the
spin resonance mode in layered unconventional superconductors that are not
strongly anisotropic, such as certain heavy-fermion compounds and potentially
the newly discovered nickelate superconductor NdNiO$_2$. Here, we use the
random-phase-approximation to calculate the dynamical spin susceptibility of 3D
superconductors with a $d_{x^2-y^2}$-wave gap symmetry and corrugated
cylindrical-like Fermi surfaces. By varying the out-of-plane hopping anisotropy
$t_z/t$, we demonstrate that the appearance of a spin resonance mode is
determined by the topology of the hot lines -- i.e. lines on the Fermi surface
that are connected by the magnetic wave-vector. For an in-plane
antiferromagnetic wave-vector, the hot lines undergo a topological transition
from open lines to closed loops at a critical $t_z/t$ value. The closed hot
lines cross the nodal superconducting lines, making the spin resonance mode
overdamped and incoherent. In contrast, for an out-of-plane antiferromagnetic
wave-vector, the hot lines remain open and the spin resonance mode remains
sharp. We discuss the experimental implications of our results for the
out-of-plane dispersion of the spin resonance mode and, more generally, for
inelastic neutron scattering experiments on unconventional superconductors.",2204.12434v2
2017-04-20,Coupled mode theory for the acoustic wave and spin wave interaction in the magphonic crystals: Propagating magnetoelastic waves,"We have investigated co-directional and contra-directional couplings between
spin wave and acoustic wave in one-dimensional periodic structure (magphonic
crystal). The system consists of two ferromagnetic layers alternating in space.
We have taken into consideration materials commonly used in magnonics: yttrium
iron garnet, CoFeB, permalloy, and cobalt. The coupled mode theory (CMT)
formalism have been successfully implemented to describe magnetoelastic
interaction as a periodic perturbation in the magphonic crystal. The results of
CMT calculations have been verified by more rigorous simulations by
frequency-domain plane wave method and time-domain finite element method. The
presented resonant coupling in the magphonic crystal is an active in-space
mechanism which spatially transfers energy between propagating spin and
acoustic modes, thus creating propagating magnetoelastic wave. We have shown,
that CMT analysis of the magnetoelastic coupling is an useful tool to optimize
and design a spin wave - acoustic wave transducer based on a magphonic
crystals. The effect of spin wave damping has been included to the model to
discuss the efficiency of such a device. Our model shows that it is possible to
obtain forward conversion of the acoustic wave to the spin wave in case of
co-directional coupling and backward conversion in case of contra-directional
coupling.",1704.06118v1
2009-04-11,Coupled Superconducting Phase and Ferromagnetic Order Parameter Dynamics,"Via a direct coupling between the magnetic order parameter and the singlet
Josephson supercurrent, we detect spin-wave resonances, and their dispersion,
in ferromagnetic Josephson junctions in which the usual insulating or metallic
barrier is replaced with a weak ferromagnet. The coupling arises within the
Fraunhofer interferential description of the Josephson effect, because the
magnetic layer acts as a time dependent phase plate. A spin-wave resonance at a
frequency ws implies a dissipation that is reflected as a depression in the
current-voltage curve of the Josephson junction when hbar ws = 2eV. We have
thereby performed a resonance experiment on only 10^7 Ni atoms.",0904.1780v1
2009-09-02,Ferroelectrical spin wave resonance,"New phenomenon is experimentally identified: ferroelectrical spin wave
resonance (FE SWR), which consist in characteristic splitting of vibration
(electronic-vibration) levels in optical spectra of interacting localized
centers. Spectral positions of ESWR lines are determined in linear approach by
quadratic dispersion law. It has been found that the values of resonance mode
amplitudes are inversely proportional to mode numbers (by low excitation
level). The prediction that Raman-ESWR and IR-ESWR are characterized by
splitting constants with different values has been confirmed. Their ratio is
approximately equal two (by the frequencies of zero modes reduced to the same
value). It is independent argument for FE SWR identification.",0909.0467v1
2012-02-29,Spin wave modes in magnetic nanodisks under in-plane magnetic field,"The size dependence of spin wave modes in a circular Permalloy (Py) nanodisk
under an in-plane magnetic field is systematically studied by using
micromagnetics simulations. We show that as the disk diameter is increased, the
resonance frequency of the backward mode deceases while that of the uniform
mode increases. The avoided crossing of resonance frequencies of the uniform
mode and the backward mode appears in the plot of the size dependence of
resonance frequencies and the backward mode turns into the so-called ""edge
mode"" for large nanodisks.",1202.6464v1
2006-04-07,Resonant Tidal Excitations of Inertial Modes in Coalescing Neutron Star Binaries,"We study the effect of resonant tidal excitation of inertial modes in neutron
stars during binary inspiral. For spin frequencies less than 100 Hz, the phase
shift in the gravitational waveform associated with the resonance is small and
does not affect the matched filtering scheme for gravitational wave detection.
For higher spin frequencies, the phase shift can become significant. Most of
the resonances take place at orbital frequencies comparable to the spin
frequency, and thus significant phase shift may occur only in the
high-frequency band (hundreds of Hertz) of gravitational wave. The exception is
a single odd-paity $m=1$ mode, which can be resonantly excited for misaligned
spin-orbit inclinations, and may occur in the low-frequency band (tens of
Hertz) of gravitational wave and induce significant (>> 1 radian) phase shift.",0604163v2
2007-03-11,Resonant switching using spin valves,"Using micromagnetics we demonstrate that the r.f. field produced by a spin
valve can be used to reverse the magnetization in a magnetic nanoparticle. The
r.f. field is generated using a current that specifically excites a uniform
spin wave in the spin valve. This current is swept such that the
chirped-frequency generated by the valve matches the angular dependent resonant
frequency of the anisotropy-dominated magnetic nanoparticle, as a result of
which the magnetization reversal occurs. The switching is fast, requires
currents similar to those used in recent experiments with spin valves, and is
stable with respect to small perturbations. This phenomenon can potentially be
employed in magnetic information storage devices or recently discussed magnetic
computing schemes.",0703271v1
2019-12-03,High partial-wave Feshbach resonances in an ultracold $^6$Li-$^{133}$Cs mixture,"We measure higher partial wave Feshbach resonances in an ultracold mixture of
fermionic $^6$Li and bosonic $^{133}$Cs by magnetic field dependent atom-loss
spectroscopy. For the $p$-wave Feshbach resonances we observe triplet
structures corresponding to different projections of the pair rotation angular
momentum onto the external magnetic field axis.
  We attribute the splittings to the spin-spin and spin-rotation couplings by
modelling the observation using a full coupled-channel calculation. Comparison
with an oversimplified model, estimating the spin-rotation coupling by
describing the weakly bound close-channel molecular state with the perturbative
multipole expansion, reveals the significant contribution of the molecular
wavefunction at short internuclear distances. Our findings highlight the
potential of Feshbach resonances in providing precise information on short- and
intermediate-range molecular couplings and wavefunctions. The observed $d$-wave
Feshbach resonances allow us to refine the LiCs singlet and triplet
ground-state molecular potential curves at large internuclear separations.",1912.01264v1
2020-12-23,Parity-controlled spin-wave excitations in synthetic antiferromagnets,"We report in this study the current-induced-torque excitation of acoustic and
optical modes in Ta/NiFe/Ru/NiFe/Ta synthetic antiferromagnet stacks grown on
SiO2/Si substrates. The two Ta layers serve as spin torque sources with the
opposite polarisations both in spin currents and Oersted fields acting on their
adjacent NiFe layers. This can create the odd symmetry of spatial spin torque
distribution across the growth direction, allowing us to observe different
spin-wave excitation efficiency from synthetic antiferromagnets excited by
homogeneous torques. We analyse the torque symmetry by in-plane angular
dependence of symmetric and anti-symmetric lineshape amplitudes for their
resonance and confirm that the parallel (perpendicular) pumping nature for the
acoustic (optical) modes in our devices, which is in stark difference from the
modes excited by spatially homogeneous torques. We also present our macrospin
model for this particular spin-torque excitation geometry, which excellently
supports our experimental observation. Our results offer capability of
controlling spin-wave excitations by local spin-torque sources and we can
explore further spin-wave control schemes based on this concept.",2012.12999v2
2004-12-30,"Noncommutative Algebras, Nano-Structures, and Quantum Dynamics Generated by Resonances","We observe ``quantum'' properties of resonance equilibrium points and
resonance univariant submanifolds in the phase space. Resonances between
Birkhoff or Floquet--Lyapunov frequencies generate quantum algebras with
polynomial commutation relations. Irreducible representations and coherent
states of these algebras correspond to certain quantum nano-structure near the
classical resonance motion. Based on this representation theory and
nano-geometry, for equations of Schr\""odinger or wave type in various regimes
and zones (up to quantum chaos borders) we describe the resonance spectral and
long-time asymptotics, resonance localization and focusing, resonance adiabatic
and spin-like effects. We discuss how the mathematical phase space
nano-structures relate to physical nanoscale objects like dots, quantum wires,
etc. We also demonstrate that even in physically macroscale Helmholtz channels
the resonance implies a specific quantum character of classical wave
propagation.",0412542v2
2016-05-12,Resonance Beyond Frequency-Matching,"Resonance, defined as the oscillation of a system when the temporal frequency
of an external stimulus matches a natural frequency of the system, is important
in both fundamental physics and applied disciplines. However, the spatial
character of oscillation is not considered in the definition of resonance. In
this work, we reveal the creation of spatial resonance when the stimulus
matches the space pattern of a normal mode in an oscillating system. The
complete resonance, which we call multidimensional resonance, is a combination
of both the spatial and the conventionally defined (temporal) resonance and can
be several orders of magnitude stronger than the temporal resonance alone. We
further elucidate that the spin wave produced by multidimensional resonance
drives considerably faster reversal of the vortex core in a magnetic nanodisk.
Our findings provide insight into the nature of wave dynamics and open the door
to novel applications.",1605.03649v2
2006-03-07,Stimulated wave of polarization in spin chains,"Stimulated wave of polarization, triggered by a flip of a single spin,
presents a simple model of quantum amplification. Previously, it has been found
that such wave can be excited in a 1D Ising chain with nearest-neighbor
interactions, irradiated by a weak resonant transverse field. Here we explore
models with more realistic Hamiltonians, in particular, with natural
dipole-dipole interactions. Results of simulations for 1D spin chains and rings
with up to nine spins are presented.",0603049v1
2007-05-02,Magneto-elastic waves in crystals of magnetic molecules,"We study magneto-elastic effects in crystals of magnetic molecules. Coupled
equations of motion for spins and sound are derived and the possibility of
strong resonant magneto-acoustic coupling is demonstrated. Dispersion laws for
interacting linear sound and spin excitations are obtained for bulk and surface
acoustic waves. We show that ultrasound can generate inverse population of spin
levels. Alternatively, the decay of the inverse population of spin levels can
generate ultrasound. Possibility of solitary waves of the magnetization
accompanied by the elastic twists is demonstrated.",0705.0371v1
2019-08-24,Chiral Pumping of Spin Waves,"We report a theory for the coherent and incoherent chiral pumping of spin
waves into thin magnetic films through the dipolar coupling with a local
magnetic transducer, such as a nanowire. The ferromagnetic resonance of the
nanowire is broadened by the injection of unidirectional spin waves that
generate a non-equilibrium magnetization in only half of the film. A
temperature gradient between the local magnet and film leads to a
unidirectional flow of incoherent magnons, i.e., a chiral spin Seebeck effect.",1908.09141v2
2002-11-26,Spin dynamics of stripes,"The spin dynamics of stripes in high-temperature superconductors and related
compounds is studied in the framework of a spin-wave theory for a simple
spin-only model. The magnon dispersion relation and the magnetic structure
factor are calculated for diagonal and vertical stripes. Acoustical as well as
optical bands are included in the analysis. The incommensurability and the
$\pi$ resonance appear as complementary features of the band structure at
different energy scales. The dependence of spin-wave velocities and resonance
frequencies on the stripe spacing and coupling is calculated. At low doping,
the resonance frequency is found to scale roughly inversely proportional to the
stripe spacing. The favorable comparison of the results with experimental data
suggests that the spin-only model provides a suitable and simple basis for
calculating and understanding the spin dynamics of stripes.",0211593v1
2013-01-24,Soliton dynamics of an atomic spinor condensate on a Ring Lattice,"We study the dynamics of macroscopically-coherent matter waves of an
ultra-cold atomic spin-one or spinor condensate on a ring lattice of six sites
and demonstrate a novel type of spatio-temporal internal Josephson effect.
Using a discrete solitary mode of uncoupled spin components as an initial
condition, the time evolution of this many-body system is found to be
characterized by two dominant frequencies leading to quasiperiodic dynamics at
various sites. The dynamics of spatially-averaged and spin-averaged degrees of
freedom, however, is periodic enabling an unique identification of the two
frequencies. By increasing the spin-dependent atom-atom interaction strength we
observe a resonance state, where the ratio of the two frequencies is a
characteristic integer multiple and the spin-and-spatial degrees of freedom
oscillate in ""unison"". Crucially, this resonant state is found to signal the
onset to chaotic dynamics characterized by a broad band spectrum. In a
ferromagnetic spinor condensate with attractive spin-dependent interactions,
the resonance is accompanied by a transition from oscillatory- to
rotational-type dynamics as the time evolution of the relative phase of the
matter wave of the individual spin projections changes from bounded to
unbounded.",1301.5851v1
2013-04-02,Coupled Magnetic Resonator Optical Waveguides - mimicking spin waves in coupled metamaterials,"Optical resonators are important devices that control the properties of light
and manipulate light-matter interaction. Various optical resonators are
designed and fabricated using different techniques. For example, in coupled
resonator optical waveguides, light energy is transported to other resonators
through near-field coupling. In recent years, magnetic optical resonators based
on LC resonance have been realized in several metallic microstructures. Such
devices possess stronger local resonance and lower radiation loss compared with
electric optical resonators. This study provides an overall introduction on the
latest progress in coupled magnetic resonator optical waveguide (CMROW).
Various waveguides composed of different magnetic resonators are presented and
Lagrangian formalism is used to describe the CMROW. Moreover, several
interesting properties of CMROW, such as abnormal dispersions and slow light
effects, are discussed and CMROW applications in nonlinear and quantum optics
are shown. Future novel nanophotonic devices can be developed using CMROW.",1304.0573v1
2017-01-23,Is there a narrow $N(1685)$?,"The helicity-dependent observable $E$ for the reaction $\gamma d\to \eta n
(p)$ with a spectator proton was recently measured by the A2 Collaboration at
MAMI in Mainz. The data were interpreted as further evidence for a narrow
resonance with spin and parity $J^P=1/2^+$ ($P_{11}$ wave). However, a full
partial wave analysis without any narrow resonance leads to an excellent
description of the data, imposing a narrow resonance with the properties
suggested by the A2 Collaboration leads to a significant deterioration of the
fit quality: there is no need for a narrow resonance.",1701.06387v2
2010-09-18,Composite excitation of Josephson phase and spin waves in Josephson junctions with ferromagnetic insulator,"Coupling of Josephson-phase and spin-waves is theoretically studied in a
superconductor/ferromagnetic insulator/superconductor (S/FI/S) junction.
Electromagnetic (EM) field inside the junction and the Josephson current
coupled with spin-waves in FI are calculated by combining Maxwell and
Landau-Lifshitz-Gilbert equations. In the S/FI/S junction, it is found that the
current-voltage (I-V) characteristic shows two resonant peaks. Voltages at the
resonant peaks are obtained as a function of the normal modes of EM field,
which indicates a composite excitation of the EM field and spin-waves in the
S/FI/S junction. We also examine another type of junction, in which a
nonmagnetic insulator (I) is located at one of interfaces between S and FI. In
such a S/I/FI/S junction, three resonant peaks appear in the I-V curve, since
the Josephson-phase couples to the EM field in the I layer.",1009.3551v3
2014-12-02,A rigorous two-dimensional model for the stripline ferromagnetic resonance response of metallic ferromagnetic films,"In this work we constructed a two-dimensional numerical model for calculation
of the stripline ferromagnetic resonance (FMR) response of metallic
ferromagnetic films. We also conducted numerical calculations by using this
software. The calculations demonstrated that the eddy current contribution to
the FMR response decreases with a decrease in the stripline width. The most
important manifestations of the conductivity (eddy current) effect are
excitation of the higher-order standing spin waves across the film thickness in
the materials for which the standing spin wave peaks would be absent in cavity
FMR measurements and strong dependence of the off-resonance series conductance
of the stripline on the stripline width. Whereas the contribution of the eddy
currents to the stripline FMR response can be very significant, because wide
striplines (100nm+) are conventionally used for the FMR measurements, it is
negligible in the case of excitation of spin waves, just because very narrow
stripline transducers (0.5-5micron wide) are required in order to excite spin
waves in metallic ferromagnetic films in a noticeable frequency/applied field
range.",1412.0777v1
2019-12-11,Reservoir computing using a spin-wave delay line active ring resonator,"The authors demonstrate the use of a propagating spin waves for implementing
a reservoir computing architecture. The proposed concept utilises an active
ring resonator comprising a magnetic thin film delay line integrated into a
feedback loop. These systems exhibit strong nonlinearity and delayed response
behaviour, two important properties required for an effective reservoir
computing implementation. In a simple design, we exploit the nonlinear damping
of spin waves at different feedback gains to inject input data into the active
ring resonator and use a microwave diode to read out the amplitude of the spin
waves circulating in the ring. We employ two baseline tasks, namely the short
term memory and parity check tasks, to evaluate the suitability of this
architecture for processing time series data.",1912.05119v1
2017-01-09,Spin-Wave Modes in Transition from a Thin Film to a Full Magnonic Crystal,"Spin-wave modes are studied under the gradual transition from a flat thin
film to a 'full' (one-dimensional) magnonic crystal. For this purpose, the
surface of a pre-patterned 36.8 nm thin permalloy film was sequentially ion
milled resulting in magnonic hybrid structures, referred to as
surface-modulated magnonic crystals, with increasing modulation depth. After
each etching step, ferromagnetic resonance measurements were performed yielding
the spin-wave resonance modes in backward-volume and Damon-Eshbach geometry.
The spin-wave spectra of these hybrid systems reveal an even larger variety of
spin-wave states compared to the 'full' magnonic crystal. The measurements are
corroborated by quasi-analytical theory and micromagnetic simulations in order
to study the changing spin-wave mode character employing spin-wave mode
profiles. In backward-volume geometry, a gradual transition from the uniform
mode in the film limit to a fundamental mode in the thin part of the magnonic
crystal was observed. Equivalently, the first and the second film modes are
transform into a center and an edge mode of the thick part of the magnonic
crystal. Simple transition rules from the $n^{\mathrm{th}}$ film mode to the
$m^{\mathrm{th}}$ mode in the 'full' magnonic crystal are formulated unraveling
the complex mode structure particularly in the backward-volume geometry. An
analogous analysis was performed in the Damon-Eshbach geometry.",1702.05675v3
2010-07-02,Spin-polarizing properties of heterostructures with magnetic nano elements,"The problem of electron resonant and non-resonant scatterings on two
magnetized barriers is studied in the one-dimension. The transfer-matrix is
built up to exactly calculate the coefficient of the electron transmittance
through the system of two magnetic barriers with non-collinear magnetizations.
The polarization of the transmitted electron wave for resonance and
non-resonance transmittances is calculated. The transmittance coefficient and
spin polarization can be drastically enhanced and controlled by the angle
between the barrier magnetizations",1007.0421v1
2005-01-26,Resonant Nernst effect in the metallic and field-induced spin density wave states of (TMTSF)2ClO4,"We examine an unusual phenomenon where, in tilted magnetic fields near magic
angles parallel to crystallographic planes, a ""giant"" resonant Nernst signal
has been observed by Wu et al.[Phys. Rev. Lett. 91 56601(2003)] in the metallic
state of an organic conducting Bechgaard salt. We show that this effect appears
to be a general feature of these materials, and is also present in the field
induced spin density wave phase with even larger amplitude. Our results place
new restrictions on models that treat the metallic state as an unconventional
density wave or as a state with finite Cooper pairing.",0501649v1
2021-02-13,Accumulation and control of spin waves in magnonic dielectric microresonators by a comb of ultrashort laser pulses,"Spin waves in magnetic microresonators are at the core of modern magnonics.
Here we demonstrate a new method of tunable excitation of different spin wave
modes in magnetic microdisks by using a train of laser pulses coming at a
repetition rate higher than the decay rate of spin precession. The microdisks
are etched in a transparent bismuth iron garnet film and the light pulses
influence the spins nonthermally through the inverse Faraday effect. The high
repetition rate of the laser stimulus of 10 GHz establishes an interplay
between the spin wave resonances in the frequency and momentum domains. As a
result, scanning of the focused laser spot near the disk boarder changes
interference pattern of the magnons and leads to a resonant dependence of the
spin wave amplitude on the external magnetic field. Apart from that, we
achieved a switching between volume and surface spin waves by a small variation
of the external magnetic field.",2102.07021v4
2021-05-23,Multifunctional operation of the double-layer ferromagnetic structure coupled by a rectangular nanoresonator,"The use of spin waves as a signal carrier requires developing the functional
elements allowing for multiplexing and demultiplexing information coded at
different wavelengths. For this purpose, we propose a system of thin
ferromagnetic layers dynamically coupled by a rectangular ferromagnetic
resonator. We show that a single and double, clockwise and counter-clockwise,
circulating modes of the resonator offer a wide possibility of control of
propagating waves. Particularly, at frequency related to the double-clockwise
circulating spin-wave mode of the resonator, the spin wave excited in one layer
is transferred to the second one where it propagates in the backward direction.
Interestingly, the wave excited in the second layer propagates in the forward
direction only in that layer. This demonstrates add-drop filtering, as well as
circulator functionality. Thus, the proposed system can become an important
part of future magnonic technology for signal routing.",2105.10875v1
2012-08-01,Spin density wave and superconductivity in CaFe_{1-x}Co_{x}AsF studied by nuclear magnetic resonance,"We performed nuclear magnetic resonance (NMR) measurements to investigate the
evolution of spin-density-wave (SDW) and superconducting (SC) states upon
electron doping in CaFe_{1-x}Co_{x}AsF, which exhibits an intermediate phase
diagram between those of LaFeAsO_{1-x}F_x and Ba(Fe_{1-x}Co_x)_2As_2. We found
that homogeneous coexistence of the incommensurate SDW and SC states occurs
only in a narrow doping region around the crossover regime, which supports
S_{+-}-wave symmetry. However, only the structural phase transition survives
upon further doping, which agrees with predictions from orbital fluctuation
theory. The transitional features upon electron doping imply that both spin and
orbital fluctuations are involved in the superconducting mechanism.",1208.0141v2
2018-09-26,Resonant magnetic induction tomography of a magnetized sphere,"We demonstrate the structural imaging of magnetostatic spin-wave modes hosted
in a millimeter-sized ferromagnetic sphere. Unlike for low-dimensional magnetic
materials, there is no prior technique to image these modes in bulk magnetized
solid of revolution. Based on resonant magnetic induction tomography in the
microwave range, our approach ensures the robust identification of these
non-trivial spin-wave modes by establishing their azimuthal and polar
dependences, starting point of magnonic fundamental studies and hybrid systems
with complex spin textures well beyond the uniform precession mode.",1809.09785v2
2012-01-17,Four Wave Mixing from Fe3+ Spins in Sapphire,"Fe3+ ions in sapphire exhibit an Electron Spin Resonance (ESR) which
interacts strongly with high-Q Whispering Gallery (WG) modes at microwave
frequencies. We report the first observation of a third-order paramagnetic
nonlinear susceptibility in such a resonator at cryogenic temperatures, and the
first demonstration of four wave mixing (FWM) using this parametric
nonlinearity. This observation of an all-microwave nonlinearity is an enabling
step towards a host of quantum measurement and control applications which
utilize spins in solids.",1201.3421v1
2012-04-11,Magnetostatic spin waves and magnetic-wave chaos in ferromagnetic films. II. Numerical simulations of non-linear waves,"A method and some results of numeric simulations of magnetostatic spin waves
in ferromagnetic films are exponded, in comparison with the theory earlier
presented in arXiv preprint 1204.0200. In particular, roles of films finiteness
(edges) and defects in formation of linear and non-linear magnetostatic wave
patterns, excitation and evolution of two-dimensional solitons, and chaotic
non-linear ferromagnetic resonance are considered.",1204.2423v1
2016-02-25,All electrical propagating spin wave spectroscopy with broadband wavevector capability,"We develop an all electrical experiment to perform the broadband
phase-resolved spectroscopy of propagating spin waves in micrometer sized thin
magnetic stripes. The magnetostatic surface spin waves are excited and detected
by scaled down to 125 nm wide inductive antennas, which award ultra broadband
wavevector capability. The wavevector selection can be done by applying an
excitation frequency above the ferromagnetic resonance. Wavevector
demultiplexing is done at the spin wave detector thanks to the rotation of the
spin wave phase upon propagation. A simple model accounts for the main features
of the apparatus transfer functions. Our approach opens an avenue for the all
electrical study of wavevector-dependent spin wave properties including
dispersion spectra or non-reciprocal propagation.",1602.08091v2
2019-11-19,Imaging non-standing spin-waves in confined micron-sized ferromagnetic structures under uniform excitation,"A non-standing character of directly imaged spin-waves in confined
micron-sized ultrathin permalloy (Ni\textsubscript{80}Fe\textsubscript{20})
structures is reported along with evidence of the possibility to alter the
observed state by modifications to the sample geometry. Using micromagnetic
simulations the presence of the spin-wave modes excited in the permalloy
stripes along with the quasi-uniform modes were calculated. The predicted
spin-waves were imaged in direct space using time resolved scanning
transmission X-ray microscopy, combined with a ferromagnetic resonance
excitation scheme (STXM-FMR). STXM-FMR measurements revealed a non-standing
character of the spin-waves. Also it was shown by micromagnetic simulations and
confirmed with STXM-FMR results that the observed character of the spin-waves
can be influenced by the local magnetic fields in different sample geometries.",1911.08281v1
2022-01-11,Edge spin wave transmission through a vertex domain wall in triangular dots,"Spin waves (SWs), being usually reflected by domain walls, could also be
channeled along them. Edge domain walls yield the interesting, and potentially
applicable to real devices property of broadband spin waves confinement to the
edges of the structure. Here we investigate through numerical simulations the
propagation of quasi one-dimensional spin waves in triangle-shaped amorphous
YIG ($Y_3Fe_5O_{12}$) micron sized ferromagnets as a function of the angle
aperture. The edge spin waves (ESWs) have been propagated over the corner in
triangles of 2 microns side with a fixed thickness of 85 nm. Parameters such as
superior vertex angle (in the range of 40$^\circ$-75$^\circ$) and applied
magnetic field have been optimized in order to obtain a higher transmission
coefficient of the ESWs over the triangle vertex. We observed that for a
certain aperture angle for which dominated ESW frequency coincides with one of
the localised DW modes, the transmission is maximized near one and the phase
shift drops to $\pi/2$ indicating resonant transmission of ESWs through the
upper corner. We compare the obtained results with existing theoretical models.
These results could contribute to the development of novel basic elements for
spin wave computing.",2201.04054v2
2011-02-10,Circularly Polarized Resonant Rayleigh Scattering and Skyrmions in the $ν$ = 1 Quantum Hall Ferromagnet,"We use the circularly polarized resonant Rayleigh scattering (RRS) to study
the quantum Hall ferromagnet at $\nu$ = 1. At this filling factor we observe a
right handed copolarized RRS which probes the Skyrmion spin texture of the
electrons in the photoexcited grounds state. The resonant scattering is not
present in the left handed copolarization, and this can be related to the
correlation between Skymionic effects, screening and spin wave excitations.
These results evidence that RRS is a valid method for the study of the spin
texture of the quantum Hall states.",1102.2185v2
2005-01-05,Stimulated wave of polarization in 1D Ising chain,"It is demonstrated that in one-dimensional Ising chain with nearest-neighbor
interactions, irradiated by a weak resonant transverse field, a stimulated wave
of flipped spins can be triggered by a flip of a single spin. This analytically
solvable model illustrates mechanisms of quantum amplification and quantum
measurement.",0501022v1
2015-09-09,Quantum spin transport and dynamics through a novel F/N junction,"We study the spin transport in the low temperature regime (often referred to
as the precession-dominated regime) between a ferromagnetic Fermi liquid (FFL)
and a normal metal metallic Fermi liquid (NFL), also known as the F/N junction,
which is considered as one of the most basic spintronic devices. In particular,
we explore the propagation of spin waves and transport of magnetization through
the interface of the F/N junction where nonequilibrium spin polarization is
created on the normal metal side of the junction by electrical spin injection.
We calculate the probable spin wave modes in the precession-dominated regime on
both sides of the junction especially on the NFL side where the system is out
of equilibrium. Proper boundary conditions at the interface are introduced to
establish the transport of the spin properties through the F/N junction. A
possible transmission conduction electron spin resonance (CESR) experiment is
suggested on the F/N junction to see if the predicted spin wave modes could
indeed propagate through the junction. Potential applications based on this
novel spin transport feature of the F/N junction are proposed in the end.",1509.02582v1
2018-11-29,Electric-Dipole Spin Resonances,"Resonance phenomena in solids generally fall into two distinct classes,
electric and magnetic, driven, respectively, by the $E$ and $H$ components of
the electromagnetic wave incident on the solid. The canonical examples of the
two types of resonances are the electron cyclotron resonance (CR) and the
electron paramagnetic resonance (EPR), originating from the electron orbital
and spin degrees of freedom, respectively. The behavior becomes considerably
more interesting (and more complicated) in the presence of the spin-orbital
interaction. In this case, a more general type of resonance may occur, which is
driven by the electric excitation mechanism and involves the spin degrees of
freedom. Such electric-dipole spin resonance (EDSR) may occur at the spin
excitation frequency or at a combination of the orbital and spin frequencies,
spanning a wide bandwidth. The EDSR phenomenon, first predicted by Rashba
(1960), has been probed experimentally in 3D solids with different crystal
symmetries, as well as in low-dimensional systems (heterojunctions, inversion
layers, dislocations and impurity states). Due to its electric dipole origin,
the EDSR features a relatively high intensity, which may exceed by orders of
magnitude the EPR intensity. This review summarizes the work on EDSR prior to
1991, laying out the theoretical framework and discussing different
experimental systems in which the EDSR-related physics can be realized and
explored.",1812.01721v1
2010-06-24,Circularly polarized modes in magnetized spin plasmas,"The influence of the intrinsic spin of electrons on the propagation of
circularly polarized waves in a magnetized plasma is considered. New eigenmodes
are identified, one of which propagates below the electron cyclotron frequency,
one above the spin-precession frequency, and another close to the
spin-precession frequency.\ The latter corresponds to the spin modes in
ferromagnets under certain conditions. In the nonrelativistic motion of
electrons, the spin effects become noticeable even when the external magnetic
field $B_{0}$ is below the quantum critical\ magnetic field strength, i.e.,
$B_{0}<$ $B_{Q} =4.4138\times10^{9}\, \mathrm{T}$ and the electron density
satisfies $n_{0} \gg n_{c}\simeq10^{32}$m$^{-3}$. The importance of electron
spin (paramagnetic) resonance (ESR) for plasma diagnostics is discussed.",1006.4878v1
2007-06-06,Resonant Scattering of Ultracold Atoms in Low Dimensions,"Low energy scattering amplitudes for two atoms in one- and two-dimensional
atomic wave guides are derived for short range isotropic and resonant
interactions in high partial wave channels. Taking into account the finite
width of the resonance which was neglected in previous works is shown to have
important implications in the properties of the confinement induced resonances.
For spin polarized fermions in quasi-1D wave guides it imposes a strong
constraint on the atomic density for achieving the Fermi Tonks Girardeau gas.
For a planar wave guide, the charateristics of the 2D induced scattering
resonances in $p$- and d-wave are determined as a function of the 3D scattering
parameters and of the wave guide frequency.",0706.0834v3
2010-08-12,Rotational Doppler Effect in Magnetic Resonance,"We compute the shift in the frequency of the spin resonance in a solid that
rotates in the field of a circularly polarized electromagnetic wave. Electron
spin resonance, nuclear magnetic resonance, and ferromagnetic resonance are
considered. We show that contrary to the case of the rotating LC circuit, the
shift in the frequency of the spin resonance has strong dependence on the
symmetry of the receiver. The shift due to rotation occurs only when rotational
symmetry is broken by the anisotropy of the gyromagnetic tensor, by the shape
of the body, or by magnetocrystalline anisotropy. General expressions for the
resonance frequency and power absorption are derived and implications for
experiment are discussed.",1008.2142v1
2020-09-30,Rotating wave approximation for quadrupole interaction with high spin,"Rotating wave approximation in a quantum spin system driven by a linearly
polarized alternating magnetic field with quadrupole interaction presents is
investigated in detail in this paper. The conventional way to employ the
rotating wave approximation is to assume the dynamics being restricted in the
reduced Hilbert space. However, when the driving strength is relatively strong
or the driving is off resonant, the leakage from the target resonance subspace
along with the effects from the counter-rotating terms cannot be neglected
anymore. We propose the rotating wave approximation applied in the full Hilbert
space to take the leakage from the target resonance subspace into account. To
include the effects from the counter-rotating terms, we utilize the
counterrotating hybridized rotating wave method in the reduced Hilbert space.
The performance of these rotating wave approximation methods is compared by
estimating the state fidelity as well as the operator fidelity and the results
reveal that different methods may be employed for different practical
circumstances.",2009.14380v2
2021-12-22,Surface Cooper pair spin waves in triplet superconductors,"We study the electrodynamics of spin triplet superconductors including
dipolar interactions, which give rise to an interplay between the collective
spin dynamics of the condensate and orbital Meissner screening currents. Within
this theory, we identify a class of spin waves that originate from the coupled
dynamics of the spin-symmetry breaking triplet order parameter and the
electromagnetic field. In particular, we study magnetostatic spin wave modes
that are localized to the sample surface. We show that these surface modes can
be excited and detected using experimental techniques such as microwave spin
wave resonance spectroscopy or nitrogen-vacancy magnetometry, and propose that
the detection of these modes offers a means for the identification of spin
triplet superconductivity.",2112.12146v2
2006-10-27,Hadronic Decays and Baryon Structure,"Relativistic constituent quark models generally describe three-quark systems
with particular interactions. The corresponding invariant mass eigenvalue
spectra and pertinent eigenstates should exhibit the multiplet structure
anticipated for baryon resonances. Taking into account the flavour content,
spin structure, and spatial distribution of the baryon wave functions together
with mass relations of the eigenvalues and decay properties of the eigenstates,
we can link the theoretical mass eigenstates with the experimentally measured
resonances. The resulting classification of baryon resonances differs in some
respects from the one suggested by the Particle Data Group. With regard to the
hadronic decay widths of light and strange baryon resonances a consistent
picture emerges only, if the classification includes two-star resonances.",0610111v1
1999-04-29,Quantum Computation as a Dynamical Process,"In this paper, we discuss the dynamical issues of quantum computation. We
demonstrate that fast wave function oscillations can affect the performance of
Shor's quantum algorithm by destroying required quantum interference. We also
show that this destructive effect can be routinely avoided by using
resonant-pulse techniques. We discuss the dynamics of resonant pulse
implementations of quantum logic gates in Ising spin systems. We also discuss
the influence of non-resonant excitations. We calculate the range of parameters
where undesirable non-resonant effects can be minimized. Finally, we describe
the ``$2\pi k$-method'' which avoids the detrimental deflection of non-resonant
qubits.",9904105v1
2013-04-01,Orbital resonances around Black holes,"We compute the length and timescales associated with resonant orbits in the
Kerr Metric for all orbital and spin parameters. Resonance induced effects are
potentially observable when the Event Horizon telescope resolves the inner
structure of Sgr A*, space-based gravitational wave detectors record
phase-shifts in the waveform during the resonant passage of a neutron star as
it spirals in to the black hole and in the frequencies of quasi periodic
oscillations for accreting black holes. The onset of geodesic chaos for
non-Kerr spacetimes should occur at the resonance locations quantified here.",1304.0330v1
2023-05-10,Symmetry and nonlinearity of spin wave resonance excited by focused surface acoustic waves,"The use of a complex ferromagnetic system to manipulate GHz surface acoustic
waves is a rich current topic under investigation, but the high-power nonlinear
regime is under-explored. We introduce focused surface acoustic waves, which
provide a way to access this regime with modest equipment. Symmetry of the
magneto-acoustic interaction can be tuned by interdigitated transducer design
which can introduce additional strain components. Here, we compare the impact
of focused acoustic waves versus standard unidirectional acoustic waves in
significantly enhancing the magnon-phonon coupling behavior. Analytical
simulation results based on modified Landau-Lifshitz-Gilbert theory show good
agreement with experimental findings. We also report nonlinear input power
dependence of the transmission through the device. This experimental
observation is supported by the micromagnetic simulation using mumax3 to model
the nonlinear dependence. These results pave the way for extending the
understanding and design of acoustic wave devices for exploration of
acoustically driven spin wave resonance physics.",2305.06259v1
2012-02-22,Temperature dependence of the resonance and low energy spin excitations in superconducting FeTe$_{0.6}$Se$_{0.4}$,"We use inelastic neutron scattering to study the temperature dependence of
the low-energy spin excitations in single crystals of superconducting
FeTe$_{0.6}$Se$_{0.4}$ ($T_c=14$ K). In the low-temperature superconducting
state, the imaginary part of the dynamic susceptibility at the electron and
hole Fermi surfaces nesting wave vector $Q=(0.5,0.5)$,
$\chi^{\prime\prime}(Q,\omega)$, has a small spin gap, a two-dimensional
neutron spin resonance above the spin gap, and increases linearly with
increasing $\hbar\omega$ for energies above the resonance. While the intensity
of the resonance decreases like an order parameter with increasing temperature
and disappears at temperature slightly above $T_c$, the energy of the mode is
weakly temperature dependent and vanishes concurrently above $T_c$. This
suggests that in spite of its similarities with the resonance in electron-doped
superconducting BaFe$_{2-x}$(Co,Ni)$_x$As$_2$, the mode in
FeTe$_{0.6}$Se$_{0.4}$ is not directly associated with the superconducting
electronic gap.",1202.5015v1
2018-12-21,Active Control of Mode Crossover and Mode Hopping of Spin Waves in a Ferromagnetic Antidot Lattice,"Active control of spin-wave dynamics is demonstrated using broadband
ferromagnetic resonance in two-dimensional Ni80Fe20 antidot lattices arranged
in hexagonal lattice with fixed lattice constant but varying antidot diameter.
A strong modification in the spin-wave spectra is obtained with the variation
in the antidot diameter as well as with the strength and orientation of the
bias magnetic field. A broad band of modes is observed for the lattice with
higher antidot diameter which decreases systematically as the antidot diameter
is reduced. A crossover between the higher frequency branches is achieved in
lattices with higher antidot diameter. In addition, the spin-wave modes in all
lattices show a strong six-fold anisotropic behaviour due to the variation of
internal field distribution as a function of the bias-field orientation. A mode
hopping-like behavior is observed in the angular dispersions of spin-wave
spectra for samples having intermediate hole diameters. Micromagnetic
simulations qualitatively reproduce the experimentally observed spin-wave modes
and the simulated mode profiles reveal the presence of extended and quantized
standing spin-wave modes in these lattices. These observations are significant
for large tunability and anisotropic propagation of spin waves in GHz frequency
magnetic devices.",1812.08929v1
2019-04-03,Collective spinon spin wave in a magnetized U(1) spin liquid,"We study the transverse dynamical spin susceptibility of the two dimensional
U(1) spinon Fermi surface spin liquid in a small applied Zeeman field. We show
that both short-range interactions, present in a generic Fermi liquid, as well
as gauge fluctuations, characteristic of the U(1) spin liquid, qualitatively
change the result based on the frequently assumed non-interacting spinon
approximation. Short-range interaction leads to a new collective mode: a
""spinon spin wave"" which splits off from the two-spinon continuum at small
momentum and disperses downward. Gauge fluctuations renormalize the
susceptibility, providing non-zero power law weight in the region outside the
spinon continuum and giving the spin wave a finite lifetime, which scales as
momentum squared. We also study the effect of Dzyaloshinskii-Moriya anisotropy
on the zero momentum susceptibility, which is measured in electron spin
resonance (ESR), and obtain a resonance linewidth linear in temperature and
varying as $B^{2/3}$ with magnetic field $B$ at low temperature. Our results
form the basis for a theory of inelastic neutrons scattering, ESR, and resonant
inelastic x-ray scattering (RIXS) studies of this quantum spin liquid state.",1904.02117v2
2016-11-02,Surface effects on ferromagnetic resonance in magnetic nanocubes,"We study the effect of surface anisotropy on the spectrum of spin-wave
excitations in a magnetic nanocluster and compute the corresponding absorbed
power. For this, we develop a general numerical method based on the (undamped)
Landau-Lifshitz equation, either linearized around the equilibrium state
leading to an eigenvalue problem or solved using a symplectic technique. For
box-shaped clusters, the numerical results are favorably compared to those of
the finite-size linear spin-wave theory. Our numerical method allows us to
disentangle the contributions of the core and surface spins to the spectral
weight and absorbed power. In regard to the recent developments in synthesis
and characterization of assemblies of well defined nano-elements, we study the
effects of free boundaries and surface anisotropy on the spin-wave spectrum in
iron nanocubes and give orders of magnitude of the expected spin-wave
resonances. For an 8 nm iron nanocube, we show that the absorbed power spectrum
should exhibit a low-energy peak around 10 GHz, typical of the uniform mode,
followed by other low-energy features that couple to the uniform mode but with
a stronger contribution from the surface. There are also high-frequency
exchange-mode peaks around 60 GHz.",1611.00614v1
2016-11-12,Parametric resonance of magnetization excited by electric field,"Manipulation of magnetization by electric field is a central goal of
spintronics because it enables energy-efficient operation of spin-based
devices. Spin wave devices are promising candidates for low-power information
processing but a method for energy-efficient excitation of short-wavelength
spin waves has been lacking. Here we show that spin waves in nanoscale magnetic
tunnel junctions can be generated via parametric resonance induced by electric
field. Parametric excitation of magnetization is a versatile method of
short-wavelength spin wave generation, and thus our results pave the way
towards energy-efficient nanomagnonic devices.",1611.03963v1
2020-11-30,Phase Shift of Planetary Waves and Wave--Jet Resonance on Tidally Locked Planets,"Recent studies found that atmospheric superrotation (i.e., west-to-east winds
over the equator) on tidally locked planets can modify the phase of planetary
waves. But, a clear relationship between the superrotation and the magnitude of
the phase shift was not examined. In this study, we re-investigate this problem
using a two-dimensional (2D) linear shallow water model with a specified
uniform zonal flow. We find that the degree of the phase shift is a monotonic
but nonlinear function of the strength of the mean flow, and the phase shift
has two limits of -$\pi$ and +$\pi$. The existence of these limits can be
explained using the energy balance of the whole system. We further show that a
resonance between the Rossby wave and the mean flow occurs when the speed of an
eastward jet approaches to the westward phase speed of the Rossby wave, or a
resonance between the Kelvin wave and the mean flow happens when the speed of a
westward jet approaches to the eastward phase speed of the Kelvin wave. The
resonance mechanism is the same as that found in the previous studies on Earth
and hot Jupiters. Moreover, in the spin-up period of a 3D global atmospheric
general circulation simulation for tidally locked rocky planet, we also find
these two phenomena: phase shift and wave--jet resonance. This study improves
the understanding of wave--mean flow interactions on tidally locked planets.",2011.14553v1
2013-05-17,Doping dependence of the spin excitations in Fe-based superconductors Fe1+yTe1-xSex,"The Fe1+yTe1-xSex series of materials is one of the prototype families of
Fe-based superconductors. To provide further insight into these materials we
present systematic inelastic neutron scattering measurements of the low energy
spin excitations for x=0.27, 0.36, 0.40, 0.49. These measurements show an
evolution of incommensurate spin excitations towards the (1/2 1/2 0) wave
vector with doping. Concentrations (x=0.40 and 0.49) which exhibit the most
robust superconducting properties have spin excitations closest to (1/2 1/2 0)
and also exhibit a strong spin resonance in the spin excitation spectrum below
Tc. The resonance signal appears to be closer to (1/2 1/2 0) than the
underlying spin excitations. We discuss the possible relationship between
superconductivity and spin excitations at the (1/2 1/2 0) wave vector and the
role that interstitial Fe may play.",1305.4108v2
2013-11-05,Effect of magnetic field on resonant tunneling in 3D waveguides of variable cross-section,"We consider an infinite three-dimensional waveguide that far from the
coordinate origin coincides with a cylinder. The waveguide has two narrows of
diameter $\varepsilon$. The narrows play the role of effective potential
barriers for the longitudinal electron motion. The part of waveguide between
the narrows becomes a ""resonator""\, and there can arise conditions for electron
resonant tunneling. A magnetic field in the resonator can change the basic
characteristics of this phenomenon. In the presence of a magnetic field, the
tunneling phenomenon is feasible for producing spin-polarized electron flows
consisting of electrons with spins of the same direction.
  We assume that the whole domain occupied by a magnetic field is in the
resonator. An electron wave function satisfies the Pauli equation in the
waveguide and vanishes at its boundary. Taking $\varepsilon$ as a small
parameter, we derive asymptotics for the probability $T(E)$ of an electron with
energy $E$ to pass through the resonator, for the ""resonant energy""\,$E_{res}$,
where $T(E)$ takes its maximal value, and for some other resonant tunneling
characteristics.",1311.1126v1
2017-09-26,"Observation of ""broad"" d-wave Feshbach resonances with a triplet structure","High partial-wave ($l\ge2$) Feshbach resonance (FR) in an ultracold mixture
of $^{85}$Rb-$^{87}$Rb atoms is investigated experimentally aided by a
partial-wave insensitive analytic multichannel quantum-defect theory (MQDT).
Two ""broad"" resonances from coupling between d-waves in both the open and
closed channels are observed and characterized. One of them shows a fully
resolved triplet structure with splitting ratio well explained by the
perturbation to the closed channel due to interatomic spin-spin interaction.
These tunable ""broad"" d-wave resonances, especially the one in the
lowest-energy open channel, could find important applications in simulating
d-wave coupling dominated many-body systems. In addition, we find that there is
generally a time and temperature requirement, associated with tunneling through
the angular momentum barrier, to establish and observe resonant coupling in
nonzero partial waves.",1709.08794v2
2021-06-22,Room And Cryogenic Temperature Behaviour of Magnetic Sensors Based on Gan/Si Single Saw Resonators,"This work analyzes resonance frequency shift vs. the applied magnetic field
strength for GHz operating GaN/Si SAW single resonators. Magnetostrictive
elements (Ni and CoFeB) were deposited in the proximity of the interdigitated
transducers (IDTs) of the resonators (A-type structures) and also over the
IDTs, after covering them with a BCB layer to avoid short circuits with IDTs
metal (B-type structures). This work targets emerging applications of SAW
resonators in driving spin wave pumping and in coupling of surface acoustic
waves (SAW) with superconducting Q-bits. Magnetic sensitivity of the SAWs was
analyzed at room temperature (RT) and at cryogenic temperatures, obtaining high
magnetic sensitivities at 16 K. According to our knowledge, GaN based SAWs are
first time used in magnetic applications; also, cryogenic behavior of magnetic
SAW sensors is first time analyzed.",2106.11605v1
2011-11-02,Proposal for a Datta-Das transistor in the quantum Hall regime,"We propose a resonant spin-field-effect transistor for chiral spin-resolved
edge states in the integer quantum Hall effect with Rashba spin-orbit
interaction. It employs a periodic array of voltage-controlled top gates that
locally modulate the Rashba spin-orbit interaction. Strong resonant spin-field
effect is achieved when the array periodicity matches the inverse of the
wave-vector difference of the two chiral states involved. Well-known techniques
of separately contacting the edge states make it possible to selectively
populate and read out the edge states, allowing full spin readout. The resonant
nature of the spin-field effect and the adiabatic character of the edge states
guarantee a high degree of robustness with respect to disorder. Our device
represents the quantum Hall version of the all-electrical Datta-Das spin-field
effect transistor.",1111.0675v3
2023-12-01,A continuous-wave and pulsed X-band electron spin resonance spectrometer operating in ultra-high vacuum for the study of low dimensional spin ensembles,"We report the development of a continuous-wave and pulsed X-band electron
spin resonance (ESR) spectrometer for the study of spins on ordered surfaces
down to cryogenic temperatures. The spectrometer operates in ultra-high vacuum
and utilizes a half-wavelength microstrip line resonator realized using
epitaxially grown copper films on single crystal Al$_2$O$_3$ substrates. The
one-dimensional microstrip line resonator exhibits a quality factor of more
than 200 at room temperature, close to the upper limit determined by radiation
losses. The surface characterizations of the copper strip of the resonator by
atomic force microscope, low-energy electron diffraction, and scanning
tunneling microscope show that the surface is atomically clean, flat, and
single crystalline. Measuring the ESR spectrum at 15 K from a few nm thick
molecular film of YPc$_2$, we find a continuous-wave ESR sensitivity of $2.6
\cdot 10^{11}~\text{spins}/\text{G} \cdot \text{Hz}^{1/2}$ indicating that a
signal-to-noise ratio of $3.9~\text{G} \cdot \text{Hz}^{1/2}$ is expected from
a monolayer of YPc$_2$ molecules. Advanced pulsed ESR experimental capabilities
including dynamical decoupling and electron-nuclear double resonance are
demonstrated using free radicals diluted in a glassy matrix.",2312.00459v2
2009-12-17,Magnetic non-collinear neutron wave resonator,"Equations for the neutron reflection amplitude from a magnetic non-collinear
wave resonator (NWR) are obtained. It is shown that resonances of the same
reflection order of neutrons experiencing spin-flip (spin-flip neutrons) appear
in pairs. Conditions under which in the resonator square enhancement of the
spin-flip neutron reflection intensity with respect to growth of the portion of
scattered and absorbed neutrons takes place, are determined.",0912.3557v2
2012-10-27,Collective coupling of a macroscopic number of single-molecule magnets with a microwave cavity mode,"We report the observation of strong coupling of a macroscopic ensemble of
~10^{16} Fe_8 molecular nanomagnets to the resonant mode of a microwave cavity.
We use millimeter-wave spectroscopy to measure the splitting of the system's
resonant frequency induced by the coupling between the spins and the cavity
mode. The magnitude of this splitting is found to scale with Sqrt[N], where N
is the number of collectively coupled spins. We control N by changing the
system's temperature and, thereby, the populations of the relevant spin energy
levels. Strong coupling is observed for two distinct transitions between spin
energy states. Our results indicate that at low temperatures nearly all of the
spins in the sample couple with the cavity's resonant mode even though there is
substantial inhomogeneous broadening of the Fe8 spin resonances.",1210.7330v1
2020-04-08,Charge-to-spin conversion efficiency in ferromagnetic nanowires by spin torque ferromagnetic resonance: Reconciling lineshape and linewidth analysis methods,"Spin orbit torques are of great interest for switching the magnetization
direction in nanostructures, moving skyrmions and exciting spin waves. The
standard method of determining their efficiency is by spin torque ferromagnetic
resonance (ST-FMR), a technique that involves analyzing the resonance linewidth
or lineshape. On microstuctures these two analysis methods are quite
consistent. Here we present ST-FMR results on permalloy (Ni$_{80}$Fe$_{20}$)
nanowires -- with widths varying from $150$ to 800 nm -- that show that the
standard model used to analyze the resonance linewidth and lineshape give
different results; the efficiency appears greatly enhanced in nanowires when
the lineshape method is used. A ST-FMR model that properly accounts for the
sample shape is presented and shows much better consistency between the two
methods. Micromagnetic simulations are used to verify the model. These results
and the more accurate nanowire model presented are of importance for
characterizing and optimizing charge-to-spin conversion efficiencies in
nanostructures.",2004.03784v1
2016-07-31,Spin resonance peak in Fe-based superconductors with unequal gaps,"We study the spin resonance in superconducting state of iron-based materials
within multiband models with two unequal gaps, $\Delta_L$ and $\Delta_S$, on
different Fermi surface pockets. We show that due to the indirect nature of the
gap entering the spin susceptibility at the nesting wave vector $\mathbf{Q}$
the total gap $\tilde\Delta$ in the bare susceptibility is determined by the
sum of gaps on two different Fermi surface sheets connected by $\mathbf{Q}$.
For the Fermi surface geometry characteristic to the most of iron pnictides and
chalcogenides, the indirect gap is either $\tilde\Delta = \Delta_L + \Delta_S$
or $\tilde\Delta = 2\Delta_L$. In the $s_{++}$ state, spin excitations below
$\tilde\Delta$ are absent unless additional scattering mechanisms are assumed.
The spin resonance appears in the $s_\pm$ superconducting state at frequency
$\omega_R \leq \tilde\Delta$. Comparison with available inelastic neutron
scattering data confirms that what is seen is the true spin resonance and not a
peak inherent to the $s_{++}$ state.",1608.00245v2
2020-01-13,Gate-tunable spin waves in antiferromagnetic atomic bilayers,"The emergence of two-dimensional (2D) layered magnetic materials has opened
an exciting playground for both fundamental studies of magnetism in 2D and
explorations of spinbased applications. Remarkable properties, including spin
filtering in magnetic tunnel junctions and gate control of magnetic states,
have recently been demonstrated in 2D magnetic materials. While these studies
focus on the static properties, dynamic magnetic properties such as excitation
and control of spin waves have remained elusive. Here we excite spin waves and
probe their dynamics in antiferromagnetic CrI3 bilayers by employing an
ultrafast optical pump/magneto-optical Kerr probe technique. We identify
sub-terahertz magnetic resonances under an in-plane magnetic field, from which
we determine the anisotropy and interlayer exchange fields and the spin damping
rates. We further show tuning of antiferromagnetic resonances by tens of
gigahertz through electrostatic gating. Our results shed light on magnetic
excitations and spin dynamics in 2D magnetic materials, and demonstrate their
unique potential for applications in ultrafast data storage and processing.",2001.04044v1
2017-10-30,Quantum Spin-Hall Effect of Light at Bound States in the Continuum,"The discovery of the topological nature of free-space light and its quantum
chiral behavior has recently raised large attention. This important scientific
endeavor features spin-based integrated quantum technologies. Herein, we
discuss a novel phenomenon based on a resonantly-enhanced quantum spin-Hall
transport of light observed in a dielectric resonator operating near the
bound-state-in-continuum (BIC) regime. The BIC mode is characterized by a
transverse photonic spin angular momentum density extended on a macroscopic
area. As such, the experimental excited mode in near-BIC regime generates
resonant surface waves characterized by spin-momentum locking and that
propagate along the symmetry axes of the structure. In addition, the generated
side waves are interpreted as an abrupt nonparaxial redirection of the exciting
far field light, which is responsible for the spin-to-orbital angular momentum
conversion evidenced in the spin-orbit asymmetry measured in the intensity of
the side waves. The experimental results are in excellent agreement with a
model that combines geometric parallel transport of light polarization and
spin-momentum locking. In addition, breaking the excitation symmetry leads to a
total spin-directive coupling. Our results reveal the possibility of a
BIC-enhanced macroscopic spin-directive coupling, a novel fundamental mechanism
of light-spin manipulation that will have strong impact on emerging quantum
technologies.",1710.10862v1
2002-08-19,Projected BCS Wave Functions for Low Dimensional Frustrated Spin Systems,"Twenty-five years after the first proposal, the question whether the ground
state of a frustrated spin-half system is well described by a spin-liquid
Resonating Valence Bond (RVB) wave function is still controversial. A
physically transparent representation of a RVB state can be obtained in
fermionic representation with a standard BCS-type pairing wave function,
working in the subspace with fixed number of electrons and no double
occupancies. In this work, we show that, using this variational wave function
with a careful parameterization of the pairing function, it is possible to
obtain an extremely accurate {\em ansatz} for the ground state of the
Heisenberg antiferromagnet with next-nearest neighbors interactions
($J_{1}{-}J_{2}$ model) in the regime of strong frustration. Indeed, in the
spin-half realization of this model, it is known that the combined effect of
frustration and zero-point motion interferes with the mechanism of
spontaneously broken symmetry, giving rise to a non-magnetic phase of purely
quantum-mechanical nature ($J_2/J_1\simeq 0.5$). This wave function is proposed
to represent the generic spin-half RVB ground state in spin liquids.",0208371v1
2018-03-02,Spin-wave induced phonon resonance in multiferroic BiFeO$_3$,"We report the direct observation of a ""resonance"" mode in the lowest-energy
optic phonon very near the zone center around (111) in the multiferroic
BiFeO$_3$ using neutron scattering methods. The phonon scattering intensity is
enhanced when antiferromagnetic (AFM) order sets in at T$_N = 640$~K, and it
increases on cooling. This ""resonance"" is confined to a very narrow region in
energy-momentum space where no spin-wave excitation intensity is expected, and
it can be modified by an external magnetic field. Our results suggest the
existence of a novel coupling between the lattice and spin fluctuations in this
multiferroic system in which the spin-wave excitations are mapped onto the
lattice vibrations via the Dzyaloshinskii-Moriya (DM) interaction.",1803.01041v1
2021-12-19,Engineering spin wave spectra in thick Ni$_{80}$Fe$_{20}$ rings by using competition between exchange and dipolar fields,"Control of the spin wave dynamics in nanomagnetic elements is very important
for the realization of a broad range of novel magnonic devices. Here we study
experimentally the spin wave resonance in thick ferromagnetic rings (100 nm)
using perpendicular ferromagnetic resonance spectroscopy. Different from what
was observed for the continuous film of the same thickness, or from ring with
similar lateral dimensions but with lower thicknesses, the spectra of thick
patterned rings show a non-monotonic dependence of the mode intensity on the
resonance field for a fixed frequency. To explain this effect, the theoretical
approach by considering the dependence of the mode profiles on both the radial
and axial coordinates was developed. It was demonstrated that such unusual
behavior is a result of the competition between exchange and dipolar fields
acting at the spin excitations in the structure under study. The calculations
are in a good agreement with the experimental results.",2112.13657v1
1999-05-16,Experimental Generation and Observation of Intrinsic Localized Spin Wave Modes in an Antiferromagnet,"By driving with a microwave pulse the lowest frequency antiferromagnetic
resonance of the quasi 1-D biaxial antiferromagnet (C_2 H_5 NH_3)_2 CuCl_4 into
an unstable region intrinsic localized spin waves have been generated and
detected in the spin wave gap. These findings are consistent with the
prediction that nonlinearity plus lattice discreteness can lead to localized
excitations with dimensions comparable to the lattice constant.",9905025v1
2008-02-13,FMR induced Josephson Current in a Superconductor/Ferromagnet/Superconductor Junction,"We propose the phase dynamics induced by spin waves in a
superconductor/ferromagnet/superconductor (SC/FM/SC) Josephson junction. The
resistively shunted junction (RSJ) model, which describes the dynamics of
superconducting phase difference, is extended to include the spin wave
excitation by ferromagnetic resonance (FMR) using the gauge invariant phase
difference between two s-wave superconductors. The current-voltage
characteristics show step structures when the magnetization in FM is driven by
tuning the microwave frequency to FMR in the SC/FM/SC junction. The result
presents a new route to observe the spin wave excitation using the Josephson
effect.",0802.1755v2
2019-03-22,Spin-wave coupling to electromagnetic cavity fields in dysposium ferrite,"Coupling of spin-waves with electromagnetic cavity field is demonstrated in
an antiferromagnet, dysprosium ferrite (DyFeO3). By measuring transmission at
0.2-0.35 THz and sweeping sample temperature, magnon-photon coupling signatures
were found at crossings of spin-wave resonances with Fabry-Perot cavity modes
formed in samples. The obtained spectra are explained in terms of classical
electrodynamics and a microscopic model.",1903.09590v2
1998-12-07,Resonant Tidal Excitations of Rotating Neutron Stars in Coalescing Binaries,"In a coalescing neutron star-neutron star (NS-NS) or neutron star-black hole
(NS-BH) binary, oscillation modes of the NS can be resonantly excited by the
companion during the final minutes of the inspiral. The resonant energy
transfer between the orbit and NS speeds up or slows down the inspiral and
induces a phase change in the emitted gravitational waves from the binary. A
tidal resonance, (jk,m), occurs when the mode frequency equals m times the
orbital frequency. For f-mode resonance to occur before coalescence, the NS
must have rapid rotation, with spin frequency nu_s>710Hz for (22,2)-resonance
and nu_s>570Hz for (33,3)-resonance (M=1.4Mo and R=10km; however, for R=15km,
these spin frequencies become 330Hz and 250Hz). Because of strong tidal
coupling, f-mode resonances induce a large change in the number of orbital
cycles, N_orb, with maximum N_orb~10-1000 for (22,2)-resonance and N_orb~1 for
(33,3)- resonance. Such resonant effects, if present, must be included in
constructing waveform templates used in searching for gravitational wave
signals. Higher order f-mode resonances can occur at slower rotation rates, but
N_orb<0.1. For the dominant g-mode (22,2)-resonance, even modest rotation
(nu_s<100Hz) can enhance the resonant effect on the orbit by shifting resonance
to a smaller orbital frequency. However, because of the weak coupling, N_orb
lies in the range 10^-3-10^-2 (depending on the NS EOS) and is probably
negligible for the purpose of detecting gravitational waves. R-mode resonances
require misaligned spin-orbit inclinations, and the dominant resonances
correspond to (22,3) and (22,1). Since tidal coupling depends strongly on
rotation rate, N_orb<10^-2(R/10km)^(10)(M/1.4Mo)^(-20/3) is negligible for
canonical NS parameters but can be appreciable if the NS radius is larger.",9812116v2
2007-09-19,Wave Excitation in Disks Around Rotating Magnetic Stars,"The accretion disk around a rotating magnetic star (neutron star, white dwarf
or T Tauri star) is subjected to periodic vertical magnetic forces from the
star, with the forcing frequency equal to the stellar spin frequency or twice
the spin frequency. This gives rise bending waves in the disk that may
influence the variabilities of the system. We study the excitation, propagation
and dissipation of these waves using a hydrodynamical model coupled with a
generic model description of the magnetic forces. The $m=1$ bending waves are
excited at the Lindblad/vertical resonance, and propagate either to larger
radii or inward toward the corotation resonance where dissipation takes place.
While the resonant torque is negligible compared to the accretion torque, the
wave nevertheless may reach appreciable amplitude and can cause or modulate
flux variabilities from the system. We discuss applications of our result to
the observed quasi-periodic oscillations from various systems, in particular
neutron star low-mass X-ray binaries.",0709.3086v2
2002-04-02,Projected wave functions for fractionalized phases of quantum spin systems,"Gutzwiller projection allows a construction of an assortment of variational
wave functions for strongly correlated systems. For quantum spin S=1/2 models,
Gutzwiller-projected wave functions have resonating-valence-bond structure and
may represent states with fractional quantum numbers for the excitations. Using
insights obtained from field-theoretical descriptions of fractionalization in
two dimensions, we construct candidate wave functions of fractionalized states
by projecting specific superconducting states. We explicitly demonstrate the
presence of topological order in these states.",0204043v1
2013-06-26,"Actuation, propagation, and detection of transverse magnetoelastic waves in ferromagnets","We study propagation of ultrasonic waves through a ferromagnetic medium with
special attention to the boundary conditions at the interface with an
ultrasonic actuator. In analogy to charge and spin transport in conductors, we
formulate the energy transport through the system as a scattering problem. We
find that the magneto-elastic coupling leads to a non-vanishing magnetic
(elastic) energy accompanying the acoustic (spin) waves with a resonantly
enhanced effect around the dispersion relation anti-crossing point. We
demonstrate the physics of excitation of magnetization dynamics via acoustic
waves injection around the ferromagnetic resonance frequency.",1306.6268v2
2014-11-06,Non-reciprocity of spin wave propagation induced by the interface Dzyaloshinskii-Moriya interaction in Py/Pt film structures,"Results of a comprehensive study by means of Brillouin spectroscopy,
complemented by Ferromagnetic Resonance characterization, of spin waves (SW)
propagating in Py/Pt bi-layers, characterized by pronounced interface
Dzyaloshinskii-Moriya interactions (IDMI) are reported. Non-conventional wave
behavior of SW travelling in opposite directions, characterized by
non-reciprocity with respect to the inversion of the sign of the SW
wave-number, has been revealed. The value of the effective IDMI constant D has
been estimated.",1411.1684v1
2015-11-13,Nonlinear Radiation Damping of Nuclear Spin Waves and Magnetoelastic Waves in Antiferromagnets,"Parallel pumping of nuclear spin waves in antiferromagnetic CsMnF3 at liquid
helium temperatures and magnetoelastic waves in antiferromagnetic FeBO3 at
liquid nitrogen temperature in a helical resonator was studied. It was found
that the absorbed microwave power is approximately equal to the irradiated
power from the sample and that the main restriction mechanism of absortption in
both cases is defined by the nonlinear radiation damping predicted about two
decades ago. We believe that the nonlinear radiation damping is a common
feature of parallel pumping technique of all normal magnetic excitations and it
can be detected by purposeful experiments.",1511.04396v1
2023-05-11,Correlation-enhanced interaction of a Bose-Einstein condensate with parametric magnon pairs and virtual magnons,"Nonlinear interactions are crucial in science and engineering. Here, we
investigate wave interactions in a highly nonlinear magnetic system driven by
parametric pumping leading to Bose--Einstein condensation of spin-wave quanta
-- magnons. Using Brillouin light scattering spectroscopy in yttrium-iron
garnet films, we found and identified a set of nonlinear processes resulting in
off-resonant spin-wave excitations -- virtual magnons. In particular, we
discovered a dynamically-strong, correlation-enhanced four-wave interaction
process of the magnon condensate with pairs of parametric magnons having
opposite wavevectors and fully correlated phases.",2305.06896v1
2017-01-09,Investigation of Feshbach Resonances in ultra-cold 40 K spin mixtures,"Magnetically-tunable Feshbach resonances are an indispensable tool for
experiments with atomic quantum gases. We report on twenty thus far unpublished
Feshbach resonances and twenty one further probable Feshbach resonances in spin
mixtures of ultracold fermionic 40 K with temperatures well below 100 nK. In
particular, we locate a broad resonance at B=389.6 G with a magnetic width of
26.4 G. Here 1 G=10^-4 T. Furthermore, by exciting low-energy spin waves, we
demonstrate a novel means to precisely determine the zero crossing of the
scattering length for this broad Feshbach resonance. Our findings allow for
further tunability in experiments with ultracold 40 K quantum gases.",1701.02085v1
2008-07-20,$^{77}$Se NMR investigation of the field-induced spin-density-wave transitions in (TMTSF)$_2$ClO$_4$,"Complementary $^{77}$Se nuclear magnetic resonance (NMR) and electrical
transport have been used to correlate the spin density dynamics with the
subphases of the field-induced spin density wave (FISDW) ground state in \tmt.
We find that the peaks in the spin-lattice relaxation rate 1/T$_1$ appear
within the metal-FISDW phase boundary and/or at first-order subphase
transitions. In the quantum limit above 25 T, the NMR data gives an insight
into the FISDW electronic structure.",0807.3119v1
2008-11-19,Excitation of spin waves on a cylindrical semiconductor heterostructure with Rashba spin-orbit interaction,"Elementary excitations in a paramagnetic semiconductor quantum well confined
to a cylindrical surface are theoretically studied on the basis of coupled
spin-charge drift-diffusion equations. The electric-field-mediated eigenmodes
are optically excited by an oscillating interference pattern, which induces a
current in the outer circuit. For a cylinder with a given radius, sharp
resonances are predicted to occur in the steady-state current response, which
are due to weakly damped spin remagnetization waves.",0811.3070v1
2010-02-13,Spin and Charge Dynamics Ruled by Antiferromagnetic Order in Iron Pnictides,"We examine the spin and charge excitations in antiferromagnetic iron
pnictides by mean-field calculations with a random phase approximation in a
five-band itinerant model. The calculated excitation spectra reproduce well
spin-wave dispersions observed in inelastic neutron scattering, with a
realistic magnetic moment for CaFe$_2$As$_2$. A particle-hole gap is found to
be crucial to obtain consistent results; we predict the spin wave in LaFeAsO
disappears at a lower energy than in CaFe$_2$As$_2$. We analyze that the charge
dynamics to make predictions for resonant inelastic x-ray scattering spectra.",1002.2701v2
2016-03-10,Resonant excitation of the spin-wave current in hybrid nanostructures,"Using the non-equilibrium statistical operator method (NSO), we have
investigated the spin transport through the interface in a
semiconductor/ferromagnetic insulator hybrid structure. We have analyzed the
approximation of effective parameters, when each of the considered subsystems
(conduction electrons, magnons, and phonons) is characterized by its effective
temperature. We have constructed the macroscopic equations, describing the
spin-wave current caused by both resonantly excited spin system of conduction
electrons and by an inhomogeneous thermal field in the ferromagnetic insulator.",1603.03207v1
2023-11-30,Antiferromagnetic droplet soliton driven by spin current,"We demonstrate that a spin current flowing through a nano-contact into a
uniaxial antiferromagnet with first- and second-order anisotropy can excite a
self-localized dynamic magnetic soliton, known as a spin-wave droplet in
ferromagnets. The droplet nucleates at a certain threshold current with the
frequency of the N\'eel vector precession laying below the antiferromagnetic
resonance. The frequency exhibits nonlinear behavior with the increasing of
applied current. At the high value of applied torque, the soliton mode
transforms, and the oscillator emits spin waves propagating in the
antiferromagnetic layer.",2311.18583v1
2019-06-27,Spin-polarized electronic surface states of Re(0001): an ab-initio investigation,"We study the electronic structure of the Re(0001) surface by means of
ab-initio techniques based on the Fully Relativistic (FR) Density Functional
Theory (DFT) and the Projector Augmented-Wave (PAW) method. We identify the
main surface states and resonances and study in detail their energy dispersion
along the main symmetry lines of the SBZ. Moreover, we discuss the effect of
spin-orbit coupling on the energy splittings and the spin-polarization of the
main surface states and resonances. Whenever possible, we compare the results
with previously studied heavy metals surfaces. We find empty resonances,
located below a gap similar to the L-gap of the (111) fcc surfaces, that have a
downward dispersion and cross the Fermi level, similarly to the recently
studied Os(0001) surface. Their spin polarization at the Fermi level is similar
to that predicted by the Rashba model, but the usual level crossing at
$\bar{\Gamma}$ is not found with our slab thickness. Moreover, for selected
states, we follow the spin polarization along the high symmetry lines,
discussing its behavior with respect to ${\bf k}_{\parallel}$, the wave-vector
parallel to the surface.",1906.12196v1
2020-01-27,Acoustic ferromagnetic resonance and spin pumping induced by surface acoustic waves,"Voltage induced magnetization dynamics of magnetic thin films is a valuable
tool to study anisotropic fields, exchange couplings, magnetization damping and
spin pumping mechanism. A particularly well established technique is the
ferromagnetic resonance (FMR) generated by the coupling of microwave photons
and magnetization eigenmodes in the GHz range. Here we review the basic
concepts of the so-called acoustic ferromagnetic resonance technique (a-FMR)
induced by the coupling of surface acoustic waves (SAW) and magnetization of
thin films. Interestingly, additional to the benefits of the microwave excited
FMR technique, the coupling between SAW and magnetization also offers fertile
ground to study magnon-phonon and spin rotation couplings. We describe the
in-plane magnetic field angle dependence of the a-FMR by measuring the
absorption / transmission of SAW and the attenuation of SAW in the presence of
rotational motion of the lattice, and show the consequent generation of spin
current by acoustic spin pumping.",2001.09581v1
2014-12-01,Experimental and Numerical Understanding of Localized Spin Wave Mode Behavior in Broadly Tunable Spatially Complex Magnetic Configurations,"Spin wave modes confined in a ferromagnetic film by the spatially
inhomogeneous magnetic field generated by a scanned micromagnetic tip of a
ferromagnetic resonance force microscope (FMRFM) enable microscopic imaging of
the internal fields and spin dynamics in nanoscale magnetic devices. Here we
report a detailed study of spin wave modes in a thin ferromagnetic film
localized by magnetic field configurations frequently encountered in FMRFM
experiments, including geometries in which the probe magnetic moment is both
parallel and antiparallel to the applied uniform magnetic field. We demonstrate
that characteristics of the localized modes, such as resonance field and
confinement radius, can be broadly tuned by controlling the orientation of the
applied field relative to the film plane. Micromagnetic simulations accurately
reproduce our FMRFM spectra allowing quantitative understanding of the
localized modes. Our results reveal a general method of generating tightly
confined spin wave modes in various geometries with excellent spatial
resolution that significantly facilitates the broad application of FMRFM. This
paves the way to imaging of magnetic properties and spin wave dynamics in a
variety of contexts for uncovering new physics of nanoscale spin excitations.",1412.0726v1
2018-10-28,Magnetic Resonance in Defect Spins mediated by Spin Waves,"In search of two level quantum systems that implement a qubit, the
nitrogen-vacancy (NV) center in diamond has been intensively studied for years.
Despite favorable properties such as remarkable defect spin coherence times,
the addressability of NV centers raises some technical issues. The coupling of
a single NV center to an external driving field is limited to short distances,
since an efficient coupling requires the NV to be separated by only a few
microns away from the source. As a way to overcome this problem, an enhancement
of coherent coupling between NV centers and a microwave field has recently been
experimentally demonstrated using spin waves propagating in an adjacent yttrium
iron garnet (YIG) film [1]. In this paper we analyze the optically detected
magnetic resonance spectra that arise when an NV center is placed on top of a
YIG film for a geometry similar to the one in the experiment. We analytically
calculate the oscillating magnetic field of the spin wave on top of the YIG
surface to determine the coupling of spin waves to the NV center. We compare
this coupling to the case when the spin waves are absent and the NV center is
driven only with the antenna field and show that the calculated coupling
enhancement is dramatic and agrees well with the one obtained in the recent
experiment.",1810.11841v1
2022-03-08,Cavity Quantum Electrodynamics Effects of Optically Cooled Nitrogen-Vacancy Centers Coupled to a High Frequency Microwave Resonator,"Recent experiments demonstrated the cooling of a microwave mode of a
high-quality dielectric resonator coupled to optically cooled nitrogen-vacancy
(NV) spins in diamond. Our recent theoretical study [arXiv:2110.10950] pointed
out the cooled NV spins can be used to realize cavity quantum electrodynamics
effects (C-QED) at room temperature. In this article, we propose to modify the
setup used in a recent diamond maser experiment [Nature 55, 493-496 (2018)],
which features a higher spin transition frequency, a lower spin-dephasing rate
and a stronger NV spins-resonator coupling, to realize better microwave mode
cooling and the room-temperature CQED effects. To describe more precisely the
optical spin cooling and the collective spin-resonator coupling, we extend the
standard Jaynes-Cumming model to account for the rich electronic and spin
levels of the NV centers. Our calculations show that for the proposed setup it
is possible to cool the microwave mode from $293$ K (room temperature) to $116$
K, which is about $72$ K lower than the previous records, and to study the
intriguing dynamics of the CQED effects under the weak-to-strong coupling
transition by varying the laser power. With simple modifications, our model can
be applied to, e.g., other solid-state spins or triplet spins of pentacene
molecules, and to investigate other effects, such as the operations of pulsed
and continuous-wave masing.",2203.04102v1
2007-12-03,Finite size effects on spin-torque driven ferromagnetic resonance in spin-valves with a Co/Ni synthetic free layer,"Spin-torque driven ferromagnetic resonance (ST-FMR) is used to study magnetic
excitations in Co/Ni synthetic layers confined in nanojunctions. Field swept
ST-FMR measurements were conducted with a magnetic field applied perpendicular
to the layer surface. The resonance lines were measured under low amplitude
excitation in a linear response regime. The resulting resonance fields were
compared with those obtained using conventional rf field driven FMR on extended
films with the same Co/Ni layer structure. A lower resonance field is found in
confined structures. The effect of both dipolar fields acting on the Co/Ni
layer emanating from other magnetic layers in the device and finite size
effects on the spin wave spectrum are discussed.",0712.0404v2
2016-05-31,The mechanical back-action of a spin-wave resonance in a magnetoelastic thin film on a surface acoustic wave,"Surface acoustic waves (SAWs) traveling on the surface of a piezoelectric
crystal can, through the magnetoelastic interaction, excite traveling spin-wave
resonance in a magnetic film deposited on the substrate. This spin-wave
resonance in the magnetic film creates a time dynamic surface stress of
magnetoelastic origin that acts back on the surface of the piezoelectric and
modifies the SAW propagation. Unlike previous analyses that treat the
excitation as a magnon-phonon polariton, here the magnetoelastic film is
treated as a perturbation modifying boundary conditions on the SAW. We use
acoustical perturbation theory to find closed form expressions for the
back-action surface stress and strain fields and the resultant SAW velocity
shifts and attenuation. We demonstrate that the shear stress fields associated
with this spin-wave back-action also generate effective surface currents on the
piezoelectric both in-phase and out-of-phase with the driving SAW potential.
Characterization of these surface currents and their applications in
determination of the magnetoelastic coupling are discussed. The perturbative
calculation is carried out explicitly to first order (a regime corresponding to
many experimental situations of current interest) and we provide a sketch of
the implications of the theory at higher order.",1605.09475v2
2009-03-26,Spin Excitations in BaFe1.84Co0.16As2 Superconductor Observed by Inelastic Neutron Scattering,"Superconductivity appears to compete against the spin-density-wave in Fe
pnictides. However, optimally cobalt doped samples show a quasi-two-dimensional
spin excitation centered at the (0.5, 0.5, L) wavevector, ""the spin resonance
peak"", that is strongly tied to the onset of superconductivity. By inelastic
neutron scattering on single crystals we show the similarities and differences
of the spin excitations in BaFe1.84Co0.16As2, with respect to the spin
excitations in the high-temperature superconducting cuprates. As in the
cuprates the resonance occurs as an enhancement to a part of the spin
excitation spectrum which extends to higher energy transfer and higher
temperature. However, unlike in the cuprates, the resonance peak in this
compound is asymmetric in energy.",0903.4621v3
2019-03-17,Spin Photonics in 3D Whispering Gallery Mode Resonators,"Whispering gallery modes are known for having orbital angular momentum,
however the interplay of local spin density, orbital angular momentum, and the
near-field interaction with quantum emitters is much less explored. Here, we
study the spin-orbital interaction of a circularly polarized dipole with the
whispering gallery modes (WGMs) of a spherical resonator. Using an exact dyadic
Green's function approach, we show that the near-field interaction between the
photonic spin of a circularly polarized dipole and the local spin density of
whispering gallery modes gives rise to unidirectional behaviour where modes
with either positive or negative orbital angular momentum are excited. We show
that this is a manifestation of spin-momentum locking using the whispering
gallery modes of the spherical resonator. We discuss the requirements for
possible experimental demonstrations using Zeeman transitions in cold atoms or
quantum dots, and outline potential applications of these previously overlooked
properties. Our work firmly establishes local spin density, momentum and decay
as a universal right-handed electromagnetic triplet for evanescent waves.",1903.07184v2
2010-08-06,Multifrequency spin resonance in diamond,"Magnetic resonance techniques provide a powerful tool for controlling spin
systems, with applications ranging from quantum information processing to
medical imaging. Nevertheless, the behavior of a spin system under strong
excitation remains a rich dynamical problem. In this paper, we examine spin
resonance of the nitrogen-vacancy center in diamond under conditions outside
the regime where the usual rotating wave approximation applies, focusing on
effects of multifrequency excitation and excitation with orientation parallel
to the spin quantization axis. Strong-field phenomena such as multiphoton
transitions and coherent destruction of tunneling are observed in the spectra
and analyzed via numerical and analytic theory. In addition to illustrating the
response of a spin system to strong multifrequency excitation, these
observations may inform techniques for manipulating electron-nuclear spin
quantum registers.",1008.1103v1
2004-12-20,Current induced spin injection and surface torque in ferromagnetic metallic junctions,"Joint influence of two effects, namely, nonequilibrium spin injection by
current, and current induced surface torque, on spin-valve type ferromagnetic
metallic junctions is considered theoretically. The CPP configuration is
assumed. The consideration is based on solving a coupled set of equations of
motion for the mobile electron and lattice magnetizations. Boundary conditions
are derived from the total magnetization flux continuity condition. A
dispersion relation is derived for current dependent spin-wave fluctuations.
The fluctuations become unstable under current density exceeding some threshold
value. Joint action of the longitudinal spin injection and the torque lowers
the instability threshold. The spin injection softens spin wave frequency near
the threshold and can pin magnetization at the injecting contact. The pinning
rises under the current increasing, so that the appearance of new spin-wave
resonance lines can be observed.",0412523v1
2015-08-06,Large spin-wave bullet in a ferrimagnetic insulator driven by spin Hall effect,"Due to its transverse nature, spin Hall effects (SHE) provide the possibility
to excite and detect spin currents and magnetization dynamics even in magnetic
insulators. Magnetic insulators are outstanding materials for the investigation
of nonlinear phenomena and for novel low power spintronics applications because
of their extremely low Gilbert damping. Here, we report on the direct imaging
of electrically driven spin-torque ferromagnetic resonance (ST-FMR) in the
ferrimagnetic insulator Y$_3$Fe$_5$O$_{12}$ based on the excitation and
detection by SHEs. The driven spin dynamics in Y$_3$Fe$_5$O$_{12}$ is directly
imaged by spatially-resolved microfocused Brillouin light scattering (BLS)
spectroscopy. Previously, ST-FMR experiments assumed a uniform precession
across the sample, which is not valid in our measurements. A strong spin-wave
localization in the center of the sample is observed indicating the formation
of a nonlinear, self-localized spin-wave `bullet'.",1508.01427v1
2010-07-19,Standing spin-wave mode structure and linewidth in partially disordered perpendicularly magnetized sub-micron Permalloy disc arrays,"Standing spin wave mode frequencies and linewidths in partially disordered
perpendicular magnetized arrays of sub-micron Permalloy discs are measured
using broadband ferromagnetic resonance and compared to analytical results from
a single, isolated disc. The measured mode structure qualitatively reproduces
the structure expected from the theory. Fitted demagnetizing parameters
decrease with increasing array disorder. The frequency difference between the
first and second radial modes is found to be higher in the measured array
systems than predicted by theory for an isolated disc. The relative frequencies
between successive spin wave modes are unaffected by reduction of the
long-range ordering of discs in the array. An increase in standing spin wave
resonance linewidth at low applied magnetic fields is observed and grows more
severe with increased array disorder.",1007.3062v5
2005-11-21,Controlling the Suhl instability: a numerical study,"Magnetization reversal (switching) using either r.f. fields or brute-force
precessional switching is currently thought to ultimately be limited by the
non-linear excitation of non-uniform spin waves, the so-called Suhl
instability. Here we show (numerically, for the case of a sphere) that this
instability can be suppressed by choosing the applied field and/or sphere
diameter in such a way that the frequencies of the modes that can be excited
through non-linear processes are off-resonance. While the results cannot be
explained by a traditional model based on plane waves, they can be understood
by projecting the actual state onto the small amplitude spin resonant
eigenfunctions.",0511496v1
2010-12-20,Probing La(0.7)Sr(0.3)MnO3 multilayers via spin wave resonances,"La(0.7)Sr(0.3)MnO3/BiFeO3 and La(0.7)Sr(0.3)MnO3/PbZr20Ti80O3 epitaxial
heterostructures have been grown on SrTiO3 substrates. Spin wave resonances are
used to study interface properties of the ferromagnetic La(0.7)Sr(0.3)MnO3. We
find that the addition of the BiFeO3 or PbZr20Ti80O3 causes out-of-plane
surface pinning of the La(0.7)Sr(0.3)MnO3. We are able to place new limits on
the exchange constant D of La(0.7)Sr(0.3)MnO3 grown on these substrates and
confirm the presence of uniaxial and biaxial anisotropies caused by the SrTiO3
substrate.",1012.4273v1
2018-12-20,One-dimensional two-component fermions with contact even-wave repulsion and SU(2) breaking near-resonant odd-wave attraction,"We consider a one-dimensional (1D) two-component atomic Fermi gas with
contact interaction in the even-wave channel (Yang-Gaudin model) and study the
effect of an SU(2) symmetry breaking near-resonant odd-wave interaction within
one of the components. Starting from the microscopic Hamiltonian, we derive an
effective field theory for the spin degrees of freedom using the bosonization
technique. It is shown that at a critical value of the odd-wave interaction
there is a first-order phase transition from a phase with zero total spin and
zero magnetization to the spin-segregated phase where the magnetization locally
differs from zero.",1812.08677v2
2003-06-04,The Orbital Order Parameter in La0.95Sr0.05MnO3 probed by Electron Spin Resonance,"The temperature dependence of the electron-spin resonance linewidth in
La0.95Sr0.05MnO3 has been determined and analyzed in the paramagnetic regime
across the orbital ordering transition. From the temperature dependence and the
anisotropy of linewidth and $g$-value the orbital order can be unambiguously
determined via the mixing angle of the wave functions of the $e_{\rm
g}$-doublet. The linewidth shows a similar evolution with temperature as
resonant x-ray scattering results.",0306088v1
2019-06-26,Electric Dipole Spin Resonance of 2D Semiconductor Spin Qubits,"Monolayer transition metal dichalcogenides (TMDs) offer a novel
two-dimensional platform for semiconductor devices. One such application,
whereby the added low dimensional crystal physics (i.e. optical spin selection
rules) may prove TMDs a competitive candidate, are quantum dots as qubits. The
band structure of TMD monolayers offers a number of different degrees of
freedom and combinations thereof as potential qubit bases, primarily electron
spin, valley isospin and the combination of the two due to the strong spin
orbit coupling known as a Kramers qubit. Pure spin qubits in monolayer MoX$_2$
(where X=S or Se) can be achieved by energetically isolating a single valley
and tuning to a spin degenerate regime within that valley by a combination of a
sufficiently small quantum dot radius and large perpendicular magnetic field.
Within such a TMD spin qubit, we theoretically analyse single qubit rotations
induced by electric dipole spin resonance. We employ a rotating wave
approximation within a second order time dependent Schrieffer-Wolf effective
Hamiltonian to derive analytic expressions for the Rabi frequency of single
qubit oscilations, and optimise the mechanism or the parameters to show
oscilations up to $250\,{\rm MHz}$.",1906.11350v1
2013-10-28,Maximal Rabi frequency of an electrically driven spin in a disordered magnetic field,"We present a theoretical study of the spin dynamics of a single electron
confined in a quantum dot. Spin dynamics is induced by the interplay of
electrical driving and the presence of a spatially disordered magnetic field,
the latter being transverse to a homogeneous magnetic field. We focus on the
case of strong driving, i.e., when the oscillation amplitude $A$ of the
electron's wave packet is comparable to the quantum dot length $L$. We show
that electrically driven spin resonance can be induced in this system by
subharmonic driving, i.e., if the excitation frequency is an integer fraction
(1/2, 1/3, etc) of the Larmor frequency. At strong driving we find that (i) the
Rabi frequencies at the subharmonic resonances are comparable to the Rabi
frequency at the fundamental resonance, and (ii) at each subharmonic resonance,
the Rabi frequency can be maximized by setting the drive strength to an
optimal, finite value. Our simple model is applied to describe electrical
control of a spin-valley qubit in a weakly disordered carbon nanotube.",1310.7350v2
2016-01-21,Spin pumping in strongly coupled magnon-photon systems,"We experimentally investigate magnon-polaritons, arising in ferrimagnetic
resonance experiments in a microwave cavity with a tuneable quality factor. To
his end, we simultaneously measure the electrically detected spin pumping
signal and microwave reflection (the ferrimagnetic resonance signal) of a
yttrium iron garnet (YIG) / platinum (Pt) bilayer in the microwave cavity. The
coupling strength of the fundamental magnetic resonance mode and the cavity is
determined from the microwave reflection data. All features of the magnetic
resonance spectra predicted by first principle calculations and an input-output
formalism agree with our experimental observations. By changing the decay rate
of the cavity at constant magnon-photon coupling rate, we experimentally tune
in and out of the strong coupling regime and successfully model the
corresponding change of the spin pumping signal. Furthermore, we observe the
coupling and spin pumping of several spin wave modes and provide a quantitative
analysis of their coupling rates to the cavity.",1601.05681v1
2016-07-06,High-Fidelity Hot Gates for Generic Spin-Resonator Systems,"We propose and analyze a high-fidelity hot gate for generic spin-resonator
systems which allows for coherent spin-spin coupling, in the presence of a
thermally populated resonator mode. Our scheme is non-perturbative, applies to
a broad class of physical systems, including for example spins coupled to
circuit-QED and surface acoustic wave resonators as well as nanomechanical
oscillators, and can be implemented readily with state-of-the-art experimental
setups. We provide and numerically verify simple expressions for the fidelity
of creating maximally entangled states under realistic conditions.",1607.01614v2
2017-08-03,Spin Resonance in the New-Structure-Type Iron-Based Superconductor CaKFe4As4,"The dynamical spin susceptibility in the new-structure-type iron-based
superconductor CaKFe$_4$As$_4$ was investigated by using a combination of
inelastic neutron scattering (INS) measurements and random phase approximation
(RPA) calculations. Powder INS measurements show that the spin resonance at
$Q_\text{res}=1.17(1)$~$\text{\AA}^{-1}$, corresponding to the $(\pi,\pi)$
nesting wave vector in tetragonal notation, evolves below $T_\text{c}$. The
characteristic energy of the spin resonance $E_\text{res}=12.5$~meV is smaller
than twice the size of the superconducting gap ($2\Delta$). The broad energy
feature of the dynamical susceptibility of the spin resonance can be explained
by the RPA calculations, in which the different superconducting gaps on
different Fermi surfaces are taken into account. Our INS and PRA studies
demonstrate that the superconducting pairing nature in CaKFe$_4$As$_4$ is the
$s_\pm$ symmetry.",1708.01006v2
2011-11-24,Spin-Wave Modes and Their Intense Excitation Effects in Skyrmion Crystals,"We theoretically study spin-wave modes and their intense excitations
activated by microwave magnetic fields in the skyrmion-crystal phase of
insulating magnets by numerically analyzing a two-dimensional spin model using
the Landau-Lifshitz-Gilbert equation. Two peaks of spin-wave resonances with
frequencies of ~1 GHz are found for in-plane a.c. magnetic field where
distribution of the out-of-plane spin components circulates around each
skyrmion core. Directions of the circulations are opposite between these two
modes, and hence the spectra exhibit salient dependence on the circular
polarization of irradiating microwave. A breathing-type mode is also found for
out-of-plane a.c. magnetic field. By intensively exciting these collective
modes, melting of the skyrmion crystal accompanied by a red shift of the
resonant frequency is achieved within nano seconds.",1111.5667v1
2018-01-22,Universal relations for spin-orbit coupled Fermi gas near an s-wave resonance,"The synthetic spin-orbit coupled quantum gases is widely studied both
experimentally and theoretically in recent years. As previous studies show,
this modification of single-body dispersion will in general couple different
partial waves and thus distort the wave-function of bound states which
determines the short-distance behavior of many-body wave function. In this
work, we focus on the two-component Fermi gas with one-dimensional or
three-dimensional spin-orbit coupling near an s-wave resonance. Using the
method of effective field theory and the operator product expansion, we derive
universal relations for both systems, and obtain the momentum distribution
matrix $\left<\psi^\dagger_a(\mathbf{q})\psi_b(\mathbf{q})\right>$ at large
$\mathbf{q}$ ($a,b$ are spin index), which shows anisotropic features. We also
discuss the experimental implication of these results depending on the
realization of the spin-orbit coupling.",1801.07001v2
2019-12-16,Spin-current manipulation of photoinduced magnetization dynamics in heavy metal / ferromagnet double layer based nanostructures,"Spin currents offer a way to control static and dynamic magnetic properties,
and therefore they are crucial for next-generation MRAM devices or spin-torque
oscillators. Manipulating the dynamics is especially interesting within the
context of photo-magnonics. In typical $3d$ transition metal ferromagnets like
CoFeB, the lifetime of light-induced magnetization dynamics is restricted to
about 1 ns, which e.g. strongly limits the opportunities to exploit the wave
nature in a magnonic crystal filtering device. Here, we investigate the
potential of spin-currents to increase the spin wave lifetime in a functional
bilayer system, consisting of a heavy metal (8 nm of $\beta$-Tantalum
(Platinum)) and 5 nm CoFeB. Due to the spin Hall effect, the heavy metal layer
generates a transverse spin current when a lateral charge current passes
through the strip. Using time-resolved all-optical pump-probe spectroscopy, we
investigate how this spin current affects the magnetization dynamics in the
adjacent CoFeB layer. We observed a linear spin current manipulation of the
effective Gilbert damping parameter for the Kittel mode from which we were able
to determine the system's spin Hall angles. Furthermore, we measured a strong
influence of the spin current on a high-frequency mode. We interpret this mode
an an exchange dominated higher order spin-wave resonance. Thus we infer a
strong dependence of the exchange constant on the spin current.",1912.07728v1
2019-07-08,Coexisting spin resonance and long-range magnetic order of Eu in EuRbFe$_4$As$_4$,"Magnetic excitations and magnetic structure of EuRbFe$_4$As$_4$ were
investigated by inelastic neutron scattering (INS), neutron diffraction, and
random phase approximation (RPA) calculations. Below the superconducting
transition temperature $T_\text{c}=36.5$~K, the INS spectra exhibit the neutron
spin resonances at $Q_\text{res}=1.27(2)$~$\text{\AA}^{-1}$ and
$1.79(3)$~$\text{\AA}^{-1}$. They correspond to the $\mathbf{Q}=(0.5,0.5,1)$
and $(0.5,0.5,3)$ nesting wave vectors, showing three dimensional nature of the
band structure. The characteristic energy of the neutron spin resonance is
$E_\text{res}=17.7(3)$~meV corresponding to $5.7(1)k_\text{B}T_\text{c}$.
Observation of the neutron spin resonance mode and our RPA calculations in
conjunction with the recent optical conductivity measurements are indicative of
the $s_\pm$ superconducting pairing symmetry in EuRbFe$_4$As$_4$. In addition
to the neutron spin resonance mode, upon decreasing temperature below the
magnetic transition temperature $T_\text{N}=15$~K, the spin wave excitation
originating in the long-range magnetic order of the Eu sublattice was observed
in the low-energy inelastic channel. Single-crystal neutron diffraction
measurements demonstrate that the magnetic propagation vector of the Eu
sublattice is $\mathbf{k}=(0, 0, 0.25)$, representing the three-dimensional
antiferromagnetic order. Linear spin wave calculations assuming the obtained
magnetic structure with the intra- and inter-plane nearest neighbor exchange
couplings of $J_1/k_\text{B}=-1.31$~K and $J_c/k_\text{B}=0.08$~K can reproduce
quantitatively the observed spin wave excitation. Our results show that
superconductivity and long-range magnetic order of Eu coexist in
EuRbFe$_4$As$_4$ whereas the coupling between them is rather weak.",1907.03839v1
2021-08-23,Reconfigurable 3D magnonic crystal: tunable and localized spin-wave excitations in CoFeB meander-shaped film,"In this work, we study experimentally by broadband ferromagnetic resonance
measurements, the dependence of the spin-wave excitation spectra on the
magnetic applied field in CoFeB meander-shaped films. Two different
orientations of the external magnetic field were explored, namely parallel or
perpendicular to the lattice cores. The interpretation of the field dependence
of the frequency and spatial profiles of major spin-wave modes were obtained by
micromagnetic simulations. We show that the vertical segments lead to the
easy-axis type of magnetic anisotropy and support the in-phase and out-of-phase
spin-wave precession amplitude in the vertical segments. The latter could
potentially be used for the design of tunable metasurfaces or in magnetic
memories based on meandering 3D magnetic films.",2108.10232v1
2003-08-13,Resonating valence bond wave function for the two dimensional fractional spin liquid,"The unconventional low-lying spin excitations, recently observed in neutron
scattering experiments on ${\rm Cs_2 Cu Cl_4}$, are explained with a spin
liquid wave function. The dispersion relation as well as the wave vector of the
incommensurate spin correlations are well reproduced within a projected BCS
wave function with gapless and fractionalized spin-1/2 excitations around the
nodes of the BCS gap function. The proposed wave function is shown to be very
accurate for one-dimensional spin-1/2 systems, and remains similarly accurate
in the two-dimensional model corresponding to ${\rm Cs_2 Cu Cl_4}$, thus
representing a good ansatz for describing spin fractionalization in two
dimensions.",0308252v2
2010-05-11,NMR Measurements of Power-Law Behavior in the Spin-Wave and Critical Regions of Ferromagnetic EuO,"Precision continuous-wave NMR measurements have been carried out over the
entire magnetization curve of EuO and are presented in tabular form. Two very
closely spaced resonances are observed and are attributed to domain and
domain-wall signals. Both of the signals are useful for analysis in the
spin-wave region. Only the domain signal is measurable above ~50K. The latter
is used for fitting Tc and the critical exponent beta. The critical-region fits
agree with previous measurements, within experimental error. The
low-temperature data exhibit a clear-cut T^2 behavior, at variance with the
expectations of conventional spin-wave theory. This result is discussed in
relation to two semi-empirical spin-wave schemes, one formulated by N.
Bykovetz, and one by U. Koebler. The NMR signal at 4.2K gives no indication of
a quadrupole splitting, in contradiction to the interpretation of several
previous spin-echo NMR spectra observed in EuO. This issue remains unresolved.",1005.1692v1
2019-12-29,Synchronized excitation of magnetization dynamics via spin waves in Bi-YIG thin film by slot line waveguide,"We have studied magnetization dynamics of a single Bi-YIG thin film by means
of the high frequency power response induced by a slot line waveguide. Multiple
absorption peaks that correspond to excitement states in magnetization dynamics
appeared without the ferromagnetic resonance (FMR) condition. The peaks were
strongly influenced by a waveguide line width and a distance between the lines.
Micromagnetics simulation reveals that each line induces a local magnetization
dynamics oscillation and generates spin waves. The spin wave that propagates
from one of the lines interferences with the other side of local magnetization
dynamics oscillation around the other line, resulting in an amplification of
the oscillation when they are in synchronization with each other. This
amplification occurs at both sides of the lines by the interference. Thus, the
possible mechanism of the excitation in the magnetization dynamics oscillation
is the synchronization of mutual magnetization dynamics oscillation via spin
waves. This technique resonantly excites the local magnetization dynamics
without the FMR condition, which is applicable as a highly coherent spin waves
source.",1912.12663v1
2021-03-10,Experimental Demonstration of a Rowland Spectrometer for Spin Waves,"We experimentally demonstrate the operation of a spin-wave Rowland
spectrometer. In the proposed device geometry, spin waves are coherently
excited on a diffraction grating and form an interference pattern that
spatially separates spectral components of the incoming signal. The diffraction
grating was created by focused-ion-beam irradiation, which was found to locally
eliminate the ferrimagnetic properties of YIG, without removing the material.
We found that in our experiments spin waves were created by an indirect
mechanism, by exploiting nonlinear resonance between the grating and the
coplanar waveguide. Our work paves the way for complex spin-wave optic devices
-- chips that replicate the functionality of integrated optical devices on a
chip-scale.",2103.06165v1
2017-12-21,Exchange-torque-induced excitation of perpendicular standing spin waves in nanometer-thick YIG films,"Spin waves in ferrimagnetic yttrium iron garnet (YIG) films with ultralow
magnetic damping are relevant for magnon-based spintronics and low-power
wave-like computing. The excitation frequency of spin waves in YIG is rather
low in weak external magnetic fields because of its small saturation
magnetization, which limits the potential of YIG films for high-frequency
applications. Here, we demonstrate how exchange-coupling to a CoFeB film
enables efficient excitation of high-frequency perpendicular standing spin
waves (PSSWs) in nanometer-thick (80 nm and 295 nm) YIG films using uniform
microwave magnetic fields. In the 295-nm-thick YIG film, we measure intense
PSSW modes up to 10th order. Strong hybridization between the PSSW modes and
the ferromagnetic resonance mode of CoFeB leads to characteristic anti-crossing
behavior in broadband spin-wave spectra. A dynamic exchange torque at the
YIG/CoFeB interface explains the excitation of PSSWs. The localized torque
originates from exchange coupling between two dissimilar magnetization
precessions in the YIG and CoFeB layers. As a consequence, spin waves are
emitted from the YIG/CoFeB interface and PSSWs form when their wave vector
matches the perpendicular confinement condition. PSSWs are not excited when the
exchange coupling between YIG and CoFeB is suppressed by a Ta spacer layer.
Micromagnetic simulations confirm the exchange-torque mechanism.",1712.08204v1
2020-01-30,Electrical spectroscopy of forward volume spin waves in perpendicularly magnetized materials,"We study the potential of all-electrical inductive techniques for the
spectroscopy of propagating forward volume spin waves. We develop a
one-dimensional model to account for the electrical signature of spin-wave
reflection and transmission between inductive antennas and validate it with
experiments on a perpendicularly magnetized Co/Ni multilayer. We describe the
influence of the antenna geometry and antenna-to-antenna separation, as well as
that of the material parameters on the lineshape of the inductive signals. For
a finite damping, the broadband character of the antenna emission in the wave
vector space imposes to take into account the growing decoherence of the
magnetization waves upon their spatial propagation. The transmission signal can
be viewed as resulting from two contributions: a first one from propagating
spin-waves leading to an oscillatory phase of the broadband transmission
coefficient, and another one originating from the distant induction of
ferromagnetic resonance because of the long-range stray fields of realistic
antennas. Depending on the relative importance of these two contributions, the
decay of the transmitted signal with the propagation distance may not be
exponential and the oscillatory character of the spin-wave phase upon
propagation may be hidden. Our model and its experimental validation allow to
define geometrical and material specifications to be met to enable the use of
forward volume spin waves as efficient information carriers.",2001.11483v1
2020-08-21,Critical couplings in topological-insulator waveguide-resonator systems observed in elastic waves,"Waveguides and resonators are core components in the large-scale integration
of electronics, photonics, and phononics, both in existing and future
scenarios. In certain situations, there is critical coupling of the two
components; i.e., no energy passes through the waveguide after the incoming
wave couples into the resonator. The transmission spectral characteristics
resulting from this phenomenon are highly advantageous for signal filtering,
switching, multiplexing, and sensing. In the present study, adopting an
elastic-wave platform, we introduce topological insulator (TI), a remarkable
achievement in condensed matter physics over the past decade, into a classical
waveguide-ring-resonator configuration. Along with basic similarities with
classical systems, a TI system has important differences and advantages, mostly
owing to the spin-momentum locked transmission states at the TI boundaries. As
an example, a two-port TI waveguide resonator can fundamentally eliminate
upstream reflections while completely retaining useful transmission spectral
characteristics, and maximize the energy in the resonator, with possible
applications being novel signal processing, gyro/sensing, lasering, energy
harvesting, and intense wave-matter interactions, using phonons, photons, or
even electrons. The present work further enhances the confidence of using
topological protection for practical device performance and functionalities,
especially considering the crucial advantage of introducing (pseudo)spins to
existing conventional configurations. More in-depth research on advancing
phononics/photonics, especially on-chip, is foreseen.",2008.09547v1
2009-03-02,Quantum electrodynamic equations for magnetic resonance- and optical spectroscopic transitions,"Quantum electrodynamic equations for magnetic resonance- and optical
spectroscopic transitions have been for the first time obtained. New phenomena
- stochastic electrical and magnetic spin wave resonances are predicted to be
the effects of EM-field quantization.",0903.0320v1
2015-03-26,Lagrangian geometrical optics of nonadiabatic vector waves and spin particles,"Linear vector waves, both quantum and classical, experience
polarization-driven bending of ray trajectories and polarization dynamics that
can be interpreted as the precession of the ""wave spin"". Both phenomena are
governed by an effective gauge Hamiltonian, which vanishes in leading-order
geometrical optics. This gauge Hamiltonian can be recognized as a
generalization of the Stern-Gerlach Hamiltonian that is commonly known for
spin-1/2 quantum particles. The corresponding reduced Lagrangians for
continuous nondissipative waves and their geometrical-optics rays are derived
from the fundamental wave Lagrangian. The resulting Euler-Lagrange equations
can describe simultaneous interactions of $N$ resonant modes, where $N$ is
arbitrary, and lead to equations for the wave spin, which happens to be a
$(N^2-1)$-dimensional spin vector. As a special case, classical equations for a
Dirac particle $(N=2)$ are deduced formally, without introducing additional
postulates or interpretations, from the Dirac quantum Lagrangian with the Pauli
term. The model reproduces the Bargmann-Michel-Telegdi equations with added
Stern-Gerlach force.",1503.07829v1
2021-02-26,Gapless Spin Wave Transport through a Quantum Canted-Antiferromagnet,"In the Landau levels of a two-dimensional electron system or when flat bands
are present, e.g. in twisted van der Waals bilayers, strong electron-electron
interaction gives rise to quantum Hall ferromagnetism with spontaneously broken
symmetries in the spin and isospin sectors. Quantum Hall ferromagnets support a
rich variety of low-energy collective excitations that are instrumental to
understand the nature of the magnetic ground states and are also potentially
useful as carriers of quantum information. Probing such collective excitations,
especially their dispersion {\omega}(k), has been experimentally challenging
due to small sample size and measurement constraints. In this work, we
demonstrate an all-electrical approach that integrates a Fabry-P\'erot cavity
with non-equilibrium transport to achieve the excitation, wave vector selection
and detection of spin waves in graphene heterostructures. Our experiments
reveal gapless, linearly dispersed spin wave excitations in the E = 0 Landau
level of bilayer graphene, thus providing direct experimental evidence for a
predicted canted antiferromagnetic order. We show that the gapless spin wave
mode propagates with a high group velocity of several tens of km/s and
maintains phase coherence over a distance of many micrometers. Its dependence
on the magnetic field and temperature agree well with the hydrodynamic theory
of spin waves. These results lay the foundation for the quest of spin
superfluidity in this high-quality material. The resonant cavity technique we
developed offers a powerful and timely method to explore the collective
excitation of many spin and isospin-ordered many-body ground states in van der
Waals heterostructures and open the possibility of engineering magnonic
devices.",2103.00018v1
2016-03-23,Multi-photon transitions and Rabi resonance in continuous wave EPR,"The study of microwave and radiofrequency multi-photon transitions in
continuous wave (CW) EPR spectroscopy is extended to a Rabi resonance
condition, when the radio frequency of the magnetic-field modulation matches
the Rabi frequency of a spin system in the microwave field. Using the
non-secular perturbation theory based on the Bogoliubov averaging method, the
analytical description of the response of the spin system is derived for all
modulation frequency harmonics. When the modulation frequency exceeds the EPR
linewidth, multi-photon transitions result in sidebands in absorption EPR
spectra measured with phase-sensitive detection at any harmonic. The saturation
of different-order multi-photon transitions is shown to be significantly
different and to be sensitive to the Rabi resonance. The noticeable frequency
shifts of sidebands are found to be the signatures of this resonance. The
inversion of two-photon lines in some spectral intervals of the out-of-phase
first-harmonic signal is predicted under passage through the Rabi resonance.
The inversion indicates the transition from absorption to stimulated emission
or vice versa, depending on the sideband. The manifestation of the primary and
secondary Rabi resonance is also demonstrated in time-resolved steady-state EPR
signals formed by all harmonics of the modulation frequency. Our results
provide a theoretical framework for future developments in multi-photon CW EPR
spectroscopy, which can be useful for samples with long spin relaxation times
and extremely narrow EPR lines",1603.07228v1
2019-07-04,Resonant Acoustic Wave Assisted Spin-Transfer-Torque Switching of Nanomagnets,"We report the possibility of achieving an order of magnitude reduction in the
energy dissipation needed to write bits in perpendicular magnetic tunnel
junctions (p-MTJs) by simulating the magnetization dynamics under a combination
of resonant surface acoustic waves (r-SAW) and spin-transfer-torque (STT). The
magnetization dynamics were simulated using the Landau-Lifshitz-Gilbert
equation under macrospin assumption with the inclusion of thermal noise. The
resonant magnetization dynamics in the magnetostrictive nanomagnet build over
few 10s of cycles of SAW application that drives the magnetization to precess
in a cone with a deflection of ~45 degrees from the perpendicular direction.
This reduces the STT current density required to switch the magnetization
direction without increasing the STT application time or degrading the
switching probability in the presence of room temperature thermal noise. This
could lead to a pathway to achieve energy efficient switching of spin transfer
torque random access memory (STTRAM) whose lateral dimensions can be scaled
aggressively despite using materials with low magnetostriction by employing
resonant excitation.",1907.02255v1
1997-03-26,Stochastic Resonance in Chaotic Spin-Wave Dynamics,"We report the first experimental observation of noise-free stochastic
resonance by utilizing the intrinsic chaotic dynamics of the system. To this
end we have investigated the effect of an external periodic modulation on
intermittent signals observed by high power ferromagnetic resonance in yttrium
iron garnet spheres. Both the signal-to-noise ratio and the residence time
distributions show the characteristic features of stochastic resonance. The
phenomena can be explained by means of a one-dimensional intermittent map. We
present analytical results as well as computer simulations.",9703018v1
2021-03-15,Ferromagnetic Resonance in Permalloy Metasurfaces,"Permalloy films with one-dimensional (1D) profile modulation of submicron
periodicity are fabricated based on commercially available DVD-R discs and
studied using ferromagnetic resonance (FMR) method and micromagnetic numerical
simulations. The main resonance position shows in-plane angular dependence
which is strongly reminiscent of that in ferromagnetic films with uniaxial
magnetic anisotropy. The main signal and additional low field lines are
attributed to multiple standing spin wave resonances defined by the grating
period. The results may present interest in magnetic metamaterials and
magnonics applications.",2103.08704v1
2016-03-02,Ferromagnetic resonance in submicron permalloy stripes,"We present the results of systematic experimental investigations and
micromagnetic simulations for the ferromagnetic resonance in rectangular
permalloy microstripes. It is shown that the resonant magnetization
oscillations have a complex spatial structure including a quasi-homogeneous
precession, lateral spin-wave resonances and localized edge modes, which
strongly depend on sample orientation in an external magnetic field.",1603.00694v1
1996-05-09,Two-magnon Raman scattering in a spin density wave antiferromagnet,"We present the results for a model calculation of resonant two-magnon Raman
scattering in a spin density wave (SDW) antiferromagnet. The resonant
enhancement of the two-magnon intensity is obtained from a microscopic analysis
of the photon-magnon coupling vertex. By combining magnon-magnon interactions
with `triple resonance` phenomena in the vertex function the resulting
intensity line shape is found to closely resemble the measured two-magnon Raman
signal in antiferromagnetic cuprates. Both, resonant and non-resonant Raman
scattering are discussed for the SDW antiferromagnet and a comparison is made
to the conventional Loudon-Fleury theory of two-magnon light scattering.",9605056v1
2008-12-18,Microwave frequency modulation in continuous-wave far-infrared ESR utilizing a quasioptical reflection bridge,"We report the development of the frequency-modulation (FM) method for
measuring electron spin resonance (ESR) absorption in the 210-420 GHz frequency
range. We demonstrate that using a high-frequency ESR spectrometer without
resonating microwave components enables us to overcome technical difficulties
associated with the FM method due to nonlinear microwave-elements, without
sacrificing spectrometer performance. FM was achieved by modulating the
reference oscillator of a 13 GHz Phase Locked Dielectric Resonator Oscillator,
and amplifying and frequency-multiplying the resulting millimeter-wave
radiation up to 210, 315 and 420 GHz. ESR spectra were obtained in reflection
mode by a lock-in detection at the fundamental modulation frequency, and also
at the second and third harmonic. Sensitivity of the setup was verified by
conduction electron spin resonance measurement in KC$_{60}$.",0812.3676v1
2009-10-29,Multipurpose High Frequency Electron Spin Resonance Spectrometer for Condensed Matter Research,"We describe a quasi-optical multifrequency ESR spectrometer operating in the
75-225 GHz range and optimized at 210 GHz for general use in condensed matter
physics, chemistry and biology. The quasi-optical bridge detects the change of
mm wave polarization at the ESR. A controllable reference arm maintains a mm
wave bias at the detector. The attained sensitivity of 2x10^10 spin/G/(Hz)1/2,
measured on a dilute Mn:MgO sample in a non-resonant probe head at 222.4 GHz
and 300 K, is comparable to commercial high sensitive X band spectrometers. The
spectrometer has a Fabry-Perot resonator based probe head to measure aqueous
solutions, and a probe head to measure magnetic field angular dependence of
single crystals. The spectrometer is robust and easy to use and may be operated
by undergraduate students. Its performance is demonstrated by examples from
various fields of condensed matter physics.",0910.5504v1
2014-07-02,Spin Waves in Ferromagnetic Insulators Coupled via a Normal Metal,"Herein, we study the spin-wave dispersion and dissipation in a ferromagnetic
insulator--normal metal--ferromagnetic insulator system. Long-range dynamic
coupling because of spin pumping and spin transfer lead to collective magnetic
excitations in the two thin-film ferromagnets. In addition, the dynamic dipolar
field contributes to the interlayer coupling. By solving the
Landau-Lifshitz-Gilbert-Slonczewski equation for macrospin excitations and the
exchange-dipole volume as well as surface spin waves, we compute the effect of
the dynamic coupling on the resonance frequencies and linewidths of the various
modes. The long-wavelength modes may couple acoustically or optically. In the
absence of spin-memory loss in the normal metal, the spin-pumping-induced
Gilbert damping enhancement of the acoustic mode vanishes, whereas the optical
mode acquires a significant Gilbert damping enhancement, comparable to that of
a system attached to a perfect spin sink. The dynamic coupling is reduced for
short-wavelength spin waves, and there is no synchronization. For intermediate
wavelengths, the coupling can be increased by the dipolar field such that the
modes in the two ferromagnetic insulators can couple despite possible small
frequency asymmetries. The surface waves induced by an easy-axis surface
anisotropy exhibit much greater Gilbert damping enhancement. These modes also
may acoustically or optically couple, but they are unaffected by thickness
asymmetries.",1407.0635v1
2023-10-09,Mapping of Spin-Wave Transport in Thulium Iron Garnet Thin Films Using Diamond Quantum Microscopy,"Spin waves, collective dynamic magnetic excitations, offer crucial insights
into magnetic material properties. Rare-earth iron garnets offer an ideal
spin-wave (SW) platform with long propagation length, short wavelength,
gigahertz frequency, and applicability to magnon spintronic platforms. Of
particular interest, thulium iron garnet (TmIG) has attracted a huge interest
recently due to its successful growth down to a few nanometers, observed
topological Hall effect and spin orbit torque-induced switching effects.
However, there is no direct spatial measurement of its SW properties. This work
uses diamond nitrogen vacancy (NV) magnetometry in combination with SW
electrical transmission spectroscopy to study SW transport properties in TmIG
thin films. NV magnetometry allows probing spin waves at the sub-micrometer
scale, seen by the amplification of the local microwave magnetic field due to
the coupling of NV spin qubits with the stray magnetic field produced by the
microwave-excited spin waves. By monitoring the NV spin resonances, the SW
properties in TmIG thin films are measured as function of the applied magnetic
field, including their amplitude, decay length (~ 50 um), and wavelength (0.8 -
2 um). These results pave the way for studying spin qubit-magnon interactions
in rare-earth magnetic insulators, relevant to quantum magnonics applications.",2310.06188v4
2015-11-05,Perpendicular standing spin wave and magnetic anisotropic study on amorphous FeTaC films,"Magnetic anisotropy, spin wave (SW) excitation and exchange stiffness
constant of amorphous FeTaC ($d$ = 20-200 nm) films were studied as a function
of thickness using micro-strip ferromagnetic resonance (MS-FMR) technique. The
MS-FMR spectra for in-plane applied magnetic field show the presence of uniform
precessional mode ($n$ = 0) along with first perpendicular standing spin wave
(PSSW) mode ($n$ = 1) especially for $d$ = 50, 100 and 200 nm films. The
angular ($\varphi_{H}$) dependence of resonance field ($H_{r}$) and magnetic
field dependence of resonance frequencies ($f_{r}$) in planar configuration for
the uniform and PSSW modes were modeled successfully by using dispersion
relation which arises from a combination of exchange and dipolar interactions.
The relevant parameters such as saturation magnetization ($4\pi M_{S}$),
uniaxial anisotropic constant ($K_{u}$), $g$-factor, and exchange stiffness
constants ($A_{ex}$) are estimated for different FeTaC film thickness. $A_{ex}$
is found to increase from 1.52(4)$\times$10$^{-7}$ to 5.0(5)$\times$10$^{-6}$
erg/cm as the thickness of film increases from 50 to 200 nm, possibly due to
surface pinning effect or significant inhomogeneity especially at higher
thickness films.",1511.01722v2
2020-08-19,Impact of intra-grain spin wave reflections on nano-contact spin torque oscillators,"We investigate the origin of the experimentally observed varying
current-frequency nonlinearity of the propagating spin wave mode in
nano-contact spin torque oscillators. Nominally identical devices with 100 nm
diameter are characterized by electrical microwave measurements and show large
variation in the generated frequency as a function of drive current. This
quantitative and qualitative device-to-device variation is described in terms
of continuous and discontinuous nonlinear transitions between linear current
intervals. The thin film grain microstructure in our samples is determined
using atomic force and scanning electron microscopy to be on the scale of 30
nm. Micromagnetic simulations show that the reflection of spin waves against
the grain boundaries results in standing wave resonance configurations. For a
simulated device with a single artificial grain, the frequency increases
linearly with the drive current until the decreased wavelength eventually
forces another spin wave anti-node to be formed. This transition results in a
discontinuous step in the frequency versus current relation. Simulations of
complete, randomly generated grain microstructures additionally shows
continuous nonlinearity and a resulting device-to-device variation in frequency
that is similar to the experimental levels. The impact of temperature from 4 K
to 300 K on the resonance mode-transition nonlinearity and frequency noise is
investigated using simulations and it is found that the peak levels of the
spectral linewidth as a function of drive current agrees quantitatively with
typical levels found in experiments at room temperature.",2008.08357v1
2019-02-25,Driving magnetization dynamics in an on-demand magnonic crystal by magneto-elastic interaction,"Using spatial light interference of ultrafast laser pulses, we generate a
lateral modulation in the magnetization profile of an otherwise uniformly
magnetized film, whose magnetic excitation spectrum is monitored via the
coherent and resonant interaction with elastic waves. We find an unusual
dependence of the magnetoelastic coupling as the externally applied magnetic
field is angle- and field-tuned relative to the wave vector of the
magnetization modulation, which can be explained by the emergence of spatially
inhomogeneous spin-wave modes. In this regard, the spatial light interference
methodology can be seen as a user-configurable, temporally windowed, on-demand
magnonic crystal, potentially of arbitrary two-dimensional shape, which allows
control and selectivity of the spatial distribution of spin waves. Calculations
of spin waves using a variety of methods, demonstrated here using the
plane-wave method and micromagnetic simulation, can identify the spatial
distribution and associated energy scales of each excitation, which opens the
door to a number of excitation methodologies beyond our chosen elastic wave
excitation.",1902.09186v1
2012-02-17,Spin-stretching modes in anisotropic magnets: spin-wave excitations in the multiferroic Ba2CoGe2O7,"We studied spin excitations of the multiferroic Ba2CoGe2O7 in high magnetic
fields up to 33 T. In the electron spin resonance and far infrared absorption
spectra we found several spin excitations beyond the two conventional magnon
modes expected for such a two-sublattice antiferromagnet. We show that a
multi-boson spin-wave theory can capture these unconventional modes, that
include spin-stretching modes associated with an oscillating magnetic dipole
(or only quadrupole) moment. The lack of the inversion symmetry allows these
modes to become electric dipole active. We expect that the spin-stretching
modes can be generally observed in inelastic neutron scattering and light
absorption experiments in a broad class of ordered S > 1/2 spin systems with
strong single-ion anisotropy and/or non-centrosymmetric lattice structure.",1202.3996v2
2012-06-04,Von Neumann Entropy Spectra and Entangled Excitations in Spin-Orbital Models,"We consider the low-energy excitations of one-dimensional spin-orbital models
which consist of spin waves, orbital waves, and joint spin-orbital excitations.
Among the latter we identify strongly entangled spin-orbital bound states which
appear as peaks in the von Neumann entropy (vNE) spectral function introduced
in this work. The strong entanglement of bound states is manifested by a
universal logarithmic scaling of the vNE with system size, while the vNE of
other spin-orbital excitations saturates. We suggest that spin-orbital
entanglement can be experimentally explored by the measurement of the dynamical
spin-orbital correlations using resonant inelastic x-ray scattering, where
strong spin-orbit coupling associated with the core hole plays a role.",1206.1062v1
2019-03-08,Intra- and inter-orbital correlated electron spin dynamics in $\rm Sr_2 Ir O_4$: spin-wave gap and spin-orbit exciton,"Transformation of Coulomb interaction terms to the pseudo-orbital basis
constituted by $J=1/2$ and $3/2$ states arising from spin-orbit coupling
provides a versatile tool. This formalism is applied to investigate magnetic
anisotropy effects on low-energy spin-wave excitations as well as high-energy
spin-orbit exciton modes in $\rm Sr_2 Ir O_4$. The Hund's coupling term
explictly yields easy-plane anisotropy, resulting in gapless (in-plane) and
gapped (out-of-plane) modes, in agreement with recent resonant inelastic x-ray
scattering (RIXS) measurements. The collective mode of inter-orbital,
spin-flip, particle-hole excitations with appropriate interaction strengths and
renormalized spin-orbit gap yields two well-defined propagating spin-orbit
exciton modes, with energy scale and dispersion in good agreement with RIXS
studies.",1903.03360v1
2022-06-14,Broadband microwave detection using electron spins in a hybrid diamond-magnet sensor chip,"Quantum sensing has developed into a main branch of quantum science and
technology. It aims at measuring physical quantities with high resolution,
sensitivity, and dynamic range. Electron spins in diamond are powerful magnetic
field sensors, but their sensitivity in the microwave regime is limited to a
narrow band around their resonance frequency. Here, we realize broadband
microwave detection using spins in diamond interfaced with a thin-film magnet.
A pump field locally converts target microwave signals to the sensor-spin
frequency via the non-linear spin-wave dynamics of the magnet. Two
complementary conversion protocols enable sensing and high-fidelity spin
control over a gigahertz bandwidth, allowing characterization of the spin-wave
band at multiple gigahertz above the sensor-spin frequency. The pump-tunable,
hybrid diamond-magnet sensor chip opens the way for spin-based sensing in the
100-gigahertz regime at small magnetic bias fields.",2206.07013v1
2023-11-15,Broad-Wavevector Spin Pumping of Flat-Band Magnons,"We report the experimental observation of large spin pumping signals in
YIG/Pt system driven by broad-wavevector spin-wave spin current. 280 nm-wide
microwave inductive antennas offer broad-wavevector excitation which, in
combination with quasi-flatband of YIG, allows a large number of magnons to
participate in spin pumping at a given frequency. Through comparison with
ferromagnetic resonance spin pumping, we attribute the enhancement of the spin
current to the multichromatic magnons. The high efficiency of spin current
generation enables us to uncover nontrivial propagating properties in ultra-low
power regions. Additionally, our study achieves the spatially separated
detection of magnons, allowing the direct extraction of the decay length. The
synergistic combination of the capability of broad-wavevector excitation,
enhanced voltage signals, and nonlocal detection provides a new avenue for the
electrical exploration of spin waves dynamics.",2311.09098v1
2004-01-20,The spin excitation spectrum in striped bilayer compounds,"The spin dynamics of bilayer cuprate compounds are studied in a basic model.
The magnetic spectral properties are calculated in linear spin-wave theory for
several stripe configurations which differ by the relative location of the
stripes in the layers. We focus on the bilayer splitting of the magnon bands
near the incommensurate low energy peaks as well as near the $\pi$ resonance,
distinguishing between the odd and even channel. We find that a x-shaped
dispersion near the $\pi$ resonance is generic for stripes. By comparison of
our results to neutron scattering data for $\mathrm{YBa_2Cu_3O_{6+x}}$ we
conclude that the stripe model is consistent with characteristic features of
bilayer high-$T_c$ compounds.",0401354v1
2008-09-04,Magnetic excitations in dipolar pyrochlore antiferromagnet Gd$_2$Sn$_2$O$_7$,"The spin dynamics in the geometrically frustrated pyrochlore antiferromagnet
$\rm Gd_2Sn_2O_7$ is studied by means of the electron spin resonance. In the
ordered phase ($T_N = 1$ K), we have detected three gapped resonance modes.
Their values agree well with the developed spin-wave theory which takes into
account the Heisenberg nearest-neighbor exchange, the single-ion anisotropy and
the long-range dipolar interactions. The theory also predicts a fourth
lowest-frequency gap, which lies beyond the experimental range of frequencies,
but determines the exponential decrease of the specific heat at low
temperature.",0809.0798v1
2011-11-26,"Evidence for a spin-quartet of nucleon resonances at 2\,GeV","Results from a multi-channel partial wave analysis of elastic and inelastic
$\pi N$ and $\gamma N$ induced reactions are presented. The analysis evidences
the existence of a spin-quartet of nucleon resonances with total angular
momenta $J^P=1/2^+,..., 7/2^+$. All states fall into a $\pm130$\,MeV mass gap
centered at 1.97\,GeV. The spin quartet is at variance with S-wave diquark
configurations required in classical di-quark models.",1111.6150v2
2023-06-01,"Nonlinear characteristics of Ti, Nb, and NbN superconducting resonators for parametric amplifiers","Superconducting resonators and parametric amplifiers are important components
in scientific systems such as kinetic inductance detector arrays,
frequency-domain multiplexers for other superconducting bolometers,
spin-ensemble based memories, and circuit quantum electrodynamics
demonstrators. In this paper, we report microwave measurements of
superconducting Ti, Nb, and NbN resonators and their use as parametric
amplifiers. These half-wave resonators were fabricated under near identical
sputtering and lithographic conditions to ensure a like-for-like comparison of
material properties. We report a wide range of properties and behaviours in
terms of transition temperatures, resistivities, rate-limiting nonlinear
response times, nonlinear dissipation, signs of the nonlinear inductances and
their dependences on temperature and resonance harmonic. We have successfully
operated Nb and NbN resonators as high gain parametric amplifiers, achieving
greater than $20\,\mathrm{dB}$ of power amplification. We have shown that for a
half-wave resonator, amplification can be realised not only in the fundamental
resonance but also in the higher harmonic resonances. Further, for materials
with high transition temperatures, e.g. Nb and NbN, amplification can be
achieved at $\sim4\,\mathrm{K}$, i.e. a temperature maintained by a pulse tube
cooler. Finally, in materials systems that have very fast response times, e.g.
NbN, we have found that a cross-harmonic type of amplification can be achieved
by placing pump tone in a different resonant mode as the signal and the idler.
This wide range of observations will have important implications on the design
and application of superconducting parametric amplifiers.",2306.00685v2
1995-09-22,Critical Dynamics of Magnets,"We review our current understanding of the critical dynamics of magnets above
and below the transition temperature with focus on the effects due to the
dipole--dipole interaction present in all real magnets. Significant progress in
our understanding of real ferromagnets in the vicinity of the critical point
has been made in the last decade through improved experimental techniques and
theoretical advances in taking into account realistic spin-spin interactions.
We start our review with a discussion of the theoretical results for the
critical dynamics based on recent renormalization group, mode coupling and spin
wave theories. A detailed comparison is made of the theory with experimental
results obtained by different measuring techniques, such as neutron scattering,
hyperfine interaction, muon--spin--resonance, electron--spin--resonance, and
magnetic relaxation, in various materials. Furthermore we discuss the effects
of dipolar interaction on the critical dynamics of three--dimensional isotropic
antiferromagnets and uniaxial ferromagnets. Special attention is also paid to a
discussion of the consequences of dipolar anisotropies on the existence of
magnetic order and the spin--wave spectrum in two--dimensional ferromagnets and
antiferromagnets. We close our review with a formulation of critical dynamics
in terms of nonlinear Langevin equations.",9509141v1
2010-02-15,High Field ESR and Magnetization of the Triangular Lattice Antiferromagnet NiGa2S4,"We report the experimental and the analytical results of electron spin
resonance (ESR) and magnetization in high magnetic fields up to about 68 T of
the quasi two-dimensional triangular lattice antiferromagnet NiGa$_2$S$_4$.
  From the temperature evolution of the ESR absorption linewidth, we find a
distinct disturbing of the development of the spin correlation by
$Z_2$-vortices between 23 K and 8.5 K. Below $T_{\rm{v}}=8.5$ K, spin-wave
calculations based on a 57$^{\circ}$ spiral spin order well explains the
frequency dependence of the ESR resonance fields and high field magnetization
processes for $H$$\parallel$$c$ and $H$$\perp$$c$, although the magnetization
for $H$$\perp$$c$ at high fields is different from the calculated one.
Furthermore, we explain the field independent specific heat with
$T^2$-dependence by the same spin-wave calculation, but the magnitude of the
specific heat is much less than the observed one. Accordingly, these results
suggest the occurrence of a $Z_2$ vortex-induced topological transition at
$T_{\rm{v}}$ and may indicate quantum effects beyond the descriptions based on
the above classical spin models.",1002.3068v1
2010-11-17,Rapid collapse of spin waves in non-uniform phases of the second Landau level,"The spin degree of freedom in quantum phases of the second Landau level is
probed by resonant light scattering. The long wavelength spin wave, which
monitors the degree of spin polarization, is at the Zeeman energy in the fully
spin-polarized state at $\nu$=3. At lower filling factors the intensity of the
Zeeman mode collapses indicating loss of polarization. A novel continuum of
low-lying excitations emerges that dominates near $\nu$=8/3 and $\nu$=5/2.
Resonant Rayleigh scattering reveals that quantum fluids for $\nu<3$ break up
into robust domain structures. While the state at $\nu$=5/2 is considered to be
fully polarized, these results reveal unprecedented roles for spin degrees of
freedom.",1011.3857v2
2008-07-23,Time-resolved and continuous-wave optical spin pumping of semiconductor quantum wells,"Experimental and theoretical studies of all-optical spin pump and probe of
resident electrons in CdTe/(Cd,Mg)Te semiconductor quantum wells are reported.
A two-color Hanle-MOKE technique (based on continuous-wave excitation) and
time-resolved Kerr rotation in the regime of resonant spin amplification (based
on pulsed excitation) provide a complementary measure of electron spin
relaxation time. Influence of electron localization on long-lived spin
coherence is examined by means of spectral and temperature dependencies.
Various scenarios of spin polarization generation (via the trion and exciton
states) are analyzed and difference between continuous-wave and pulsed
excitations is considered. Effects related to inhomogeneous distribution of
$g$-factor and anisotropic spin relaxation time on measured quantities are
discussed.",0807.3640v1
2017-11-27,Surprises from the spins: astrophysics and relativity with detections of spinning black-hole mergers,"Measurements of black-hole spins are of crucial importance to fulfill the
promise of gravitational-wave astronomy. On the astrophysics side, spins are
perhaps the cleanest indicator of black-hole evolutionary processes, thus
providing a preferred way to discriminate how LIGO's black holes form. On the
relativity side, spins are responsible for peculiar dynamical phenomena (from
precessional modulations in the long inspiral to gravitational-wave recoils at
merger) which encode precious information on the underlying astrophysical
processes. I present some examples to explore this deep and fascinating
interplay between spin dynamics (relativity) and environmental effects
(astrophysics). Black-hole spins indeed hide remarkable surprises on both
fronts: morphologies, resonances, constraints on supernova kicks, multiple
merger generations and more...",1711.10038v1
2011-08-22,Acoustic spin pumping: Direct generation of spin currents from sound waves in Pt/Y3Fe5O12 hybrid structures,"Using a Pt/Y3Fe5O12 (YIG) hybrid structure attached to a piezoelectric
actuator, we demonstrate the generation of spin currents from sound waves. This
""acoustic spin pumping"" (ASP) is caused by the sound wave generated by the
piezoelectric actuator, which then modulates the distribution function of
magnons in the YIG layer and results in a pure-spin-current injection into the
Pt layer across the Pt/YIG interface. In the Pt layer, this injected spin
current is converted into an electric voltage due to the inverse spin-Hall
effect (ISHE). The ISHE voltage induced by the ASP is detected by measuring
voltage in the Pt layer at the piezoelectric resonance frequency of the
actuator coupled with the Pt/YIG system. The frequency-dependent measurements
enable us to separate the ASP-induced signals from extrinsic heating effects.
Our model calculation based on the linear response theory provides us with a
qualitative and quantitative understanding of the ASP in the Pt/YIG system.",1108.4238v1
2011-02-16,A semi-classical approach to electron spin resonance in quantum spin systems,"We develop a semi-classical approximation to electron spin resonance in
quantum spin systems, based on the rotor or non-linear sigma model. The
classical time evolution is studied using molec- ular dynamics while random
initial conditions are sampled using classical Monte Carlo methods. Although
the approximation may be especially powerful in two dimensions, we apply it
here to one- dimensional systems of large spin at intermediate temperatures, in
the presence of staggered and uniform magnetic fields. We first test the
validity of the semi-classical approximation by comparing the magnetization to
quantum Monte Carlo results on S = 2 chains. Then we calculate the ESR
spectrum, finding broad coexisting paramagnetic and spin wave resonances.",1102.3239v1
2011-10-13,Evolution of the Kondo resonance feature and its relationship to spin-orbit coupling across the quantum critical point in Ce2Rh{1-x}CoxSi3,"We investigate the evolution of the electronic structure of Ce2Rh{1-x}CoxSi3
as a function of x employing high resolution photoemission spectroscopy. Co
substitution at the Rh sites in antiferromagnetic Ce2RhSi3 leads to a
transition from an antiferromagnetic system to a Kondo system, Ce2CoSi3 via the
Quantum Critical Point (QCP). High resolution photoemission spectra reveal
distinct signature of the Kondo resonance feature (KRF) and its spin orbit
split component (SOC) in the whole composition range indicating finite Kondo
temperature scale at the quantum critical point. We observe that the intensity
ratio of the Kondo resonance feature and its spin orbit split component,
KRF/SOC gradually increases with the decrease in temperature in the strong
hybridization limit. The scenario gets reversed if the Kondo temperature
becomes lower than the magnetic ordering temperature. While finite Kondo
temperature within the magnetically ordered phase indicates applicability of
the spin density wave picture at the approach to QCP, the dominant temperature
dependence of the spin-orbit coupled feature suggests importance of spin-orbit
interactions in this regime.",1110.2836v1
2017-02-03,Spin qubit manipulation of acceptor bound states in group IV quantum wells,"The large spin-orbit coupling in the valence band of group IV semiconductors
provides an electric field knob for spin-qubit manipulation. This fact can be
exploited with acceptor based qubits. Spin manipulation of holes bound to
acceptors in engineered SiGe quantum wells depends very strongly on the
electric field applied and on the heterostructure parameters. The g-factor is
enhanced by the Ge content and can be tuned by shifting the hole wave-function
between the heterostructure constituent layers. The lack of inversion symmetry
induced both by the quantum well and the electric fields together with the
g-factor tunability allows the possibility of different qubit manipulation
methods such as electron spin resonance, electric dipole spin resonance and
g-tensor modulation resonance. Rabi frequencies up to hundreds of MHz can be
achieved with heavy-hole qubits, and of the order of GHz with light-hole
qubits.",1702.00960v1
2023-03-17,Low-energy spin excitations in optimally doped CaFe$_{0.88}$Co$_{0.12}$AsF superconductor studied with inelastic neutron scattering,"There are few inelastic neutron scattering (INS) reports on the
superconducting single crystals of FeAs-1111 system, even though it was first
discovered in 2008, due to the extreme difficulty in large single crystal
growth. In this paper, we have studied the low-energy spin excitations in the
optimally electron-doped CaFe$_{0.88}$Co$_{0.12}$AsF single crystals with
$T_\mathrm{c}$ = 21 K by INS. The resonance energy of the superconducting spin
resonant mode with $E_\mathrm{r}$ = 12 meV amounts to 6.6
$k_\mathrm{B}$$T_\mathrm{c}$, which constitutes the largest
$E_\mathrm{r}$/$k_\mathrm{B}$$T_\mathrm{c}$ ratio among iron-based
superconductors reported to date. The large ratio implies a strong coupling
between conduction electrons and magnetic excitations in
CaFe$_{0.88}$Co$_{0.12}$AsF. The resonance possesses a magnonlike upward
dispersion along transverse direction due to the anisotropy of spin-spin
correlation length within $ab$ plane in the normal-state, which points to a
spin fluctuation mediated sign-reversed ${s}\mathbf\pm$ wave pairing in
CaFe$_{0.88}$Co$_{0.12}$AsF.",2303.09787v2
2009-02-04,Spin gap and magnetic resonance in superconducting BaFe$_{1.9}$Ni$%_{0.1}$As$_{2}$,"We use neutron spectroscopy to determine the nature of the magnetic
excitations in superconducting BaFe$_{1.9}$Ni$_{0.1}$As$_{2}$ ($T_{c}=20$ K).
Above $T_{c}$ the excitations are gapless and centered at the commensurate
antiferromagnetic wave vector of the parent compound, while the intensity
exhibits a sinusoidal modulation along the c-axis. As the superconducting state
is entered a spin gap gradually opens, whose magnitude tracks the
$T$-dependence of the superconducting gap observed by angle resolved
photoemission. Both the spin gap and magnetic resonance energies are
temperature \textit{and} wave vector dependent, but their ratio is the same
within uncertainties. These results suggest that the spin resonance is a
singlet-triplet excitation related to electron pairing and superconductivity.",0902.0813v1
2015-03-29,Low-non-linearity spin-torque oscillations driven by ferromagnetic nanocontacts,"Spin-torque oscillators are strong candidates as nano-scale microwave
generators and detectors. However, because of large amplitude-phase coupling
(non-linearity), phase noise is enhanced over other linear auto-oscillators.
One way to reduce nonlinearity is to use ferromagnetic layers as a resonator
and excite them at localized spots, making a resonator-excitor pair. We
investigated the excitation of oscillations in dipole-coupled ferromagnetic
layers, driven by localized current at ferromagnetic nano-contacts.
Oscillations possessed properties of optical-mode spin-waves and at low field
($\approx$200 Oe) had high frequency (15 GHz), a moderate precession amplitude
(2--3$^\circ$), and a narrow spectral linewidth ($<$3 MHz) due to localized
excitation at nano-contacts. Micromagnetic simulation showed emission of
resonator's characteristic optical-mode spin-waves from disturbances generated
by domain-wall oscillations at nano-contacts.",1503.08408v2
2018-01-28,Clean Os(0001) electronic surface states: a first-principle fully relativistic investigation,"We analyze the electronic structure of the Os(0001) surface by means of
first-principle calculations based on Fully Relativistic (FR) Density
Functional Theory (DFT) and a Projector Augmented-Wave (PAW) approach. We
investigate surface states and resonances analyzing their spin-orbit induced
energy splitting and their spin polarization. The results are compared with
previously studied surfaces Ir(111), Pt(111), and Au(111). We do not find any
surface state in the gap similar to the L-gap of the (111) fcc surfaces, but
find Rashba split resonances that cross the Fermi level and, as in the recently
studied Ir(111) surface, have a characteristic downward dispersion. Moreover,
for some selected surface states we study the spin polarization with respect to
${\bf k}_{\parallel}$, the wave-vector parallel to the surface. In some cases,
such as the Rashba split resonances, the spin polarization shows a smooth
behavior with slow rotations, in others the rotation is faster, due to mixing
and anti-crossing of the states.",1801.09267v1
2021-12-22,Neutron Scattering Studies of the Breathing Pyrochlore Antiferromagnet LiGaCr$_{4}$O$_{8}$,"We report neutron scattering measurements of the spinel oxide
LiGaCr$_{4}$O$_{8}$, in which magnetic ions Cr$^{3+}$ form a breathing
pyrochlore lattice. Our experiments reveal the coexistence of a nearly
dispersionless resonance mode and dispersive spin wave excitations in the
magnetically ordered state, which can be quantitatively described by a quantum
spin model of hexagonal loops and linear spin wave theory with the same set of
exchange parameters, respectively. Comparison to other Cr spinel oxides reveals
a linear relationship between the resonance energy and lattice constant across
all these materials, which is in agreement with our hexagonal loop
calculations. Our results suggest a unified picture for spin resonances in Cr
spinel oxides.",2112.11709v1
2012-06-15,Spin noise in quantum dot ensembles,"We study theoretically spin fluctuations of resident electrons or holes in
singly charged quantum dots. The effects of external magnetic field and
effective fields caused by the interaction of electron and nuclei spins are
analyzed. The fluctuations of spin Faraday, Kerr and ellipticity signals
revealing the spin noise of resident charge carriers are calculated for the
continuous wave probing at the singlet trion resonance.",1206.3479v2
2020-11-11,Polariton spin jets through optical control,"We demonstrate spin polarized jets in extended systems of ballistic
exciton-polariton condensates in semiconductor microcavities using optical
non-resonant excitation geometries. The structure of the spin jets is
determined by the digitally reprogrammable, spatially non-uniform, degree of
circular polarization of the excitation laser. The presence of the laser
excitation, strong particle interactions, and spin-relaxation leads to a
tunable spin-dependent potential landscape for polaritons, with the appearance
of intricate polarization patterns due to coherent matter-wave interference.
Our work realizes polarization-structured coherent light sources in the absence
of gauge fields.",2011.05725v1
2009-10-30,Observation of a J^PC = 1-+ exotic resonance in diffractive dissociation of 190 GeV/c pi- into pi- pi- pi+,"The COMPASS experiment at the CERN SPS has studied the diffractive
dissociation of negative pions into the pi- pi- pi+ final state using a 190
GeV/c pion beam hitting a lead target. A partial wave analysis has been
performed on a sample of 420000 events taken at values of the squared
4-momentum transfer t' between 0.1 and 1 GeV^2/c^2. The well-known resonances
a1(1260), a2(1320), and pi2(1670) are clearly observed. In addition, the data
show a significant natural parity exchange production of a resonance with
spin-exotic quantum numbers J^PC = 1-+ at 1.66 GeV/c^2 decaying to rho pi. The
resonant nature of this wave is evident from the mass-dependent phase
differences to the J^PC = 2-+ and 1++ waves. From a mass-dependent fit a
resonance mass of 1660 +- 10+0-64 MeV/c^2 and a width of 269+-21+42-64 MeV/c^2
is deduced.",0910.5842v3
2010-09-15,Mixing of fermion fields of opposite parities and baryon resonances,"We consider a loop mixing of two fermion fields of opposite parities whereas
the parity is conserved in a Lagrangian. Such kind of mixing is specific for
fermions and has no analogy in boson case. Possible applications of this effect
may be related with physics of baryon resonances. The obtained matrix
propagator defines a pair of unitary partial amplitudes which describe the
production of resonances of spin $J$ and different parity ${1/2}^{\pm}$ or
${3/2}^{\pm}$. The use of our amplitudes for joint description of $\pi N$
partial waves $P_{13}$ and $D_{13}$ shows that the discussed effect is clearly
seen in these partial waves as the specific form of interference between
resonance and background. Another interesting application of this effect may be
a pair of partial waves $S_{11}$ and $P_{11}$ where the picture is more
complicated due to presence of several resonance states.",1009.2845v2
2015-11-24,Inverse Spin Hall Effect from pulsed Spin Current in Organic Semiconductors with Tunable Spin-Orbit Coupling,"Exploration of spin-currents in organic semiconductors (OSECs) induced by
resonant microwave absorption in ferromagnetic substrates has been of great
interest for potential spintronics applications. Due to the inherently weak
spin-orbit coupling (SOC) of OSECs, their inverse spin Hall effect (ISHE)
response is very subtle; limited by the microwave power applicable under
continuous-wave (cw) excitation. Here we introduce a novel approach for
generating significant ISHE signals using pulsed ferromagnetic resonance, where
the ISHE is ~2-3 orders of magnitude larger compared to cw excitation. This
strong ISHE enables us to investigate a variety of OSECs ranging from
pi-conjugated polymers with strong SOC that contain intrachain platinum atoms,
to weak SOC polymers, to C60 films, where the SOC is predominantly caused by
the molecule surface curvature. The pulsed-ISHE technique offers a robust route
for efficient injection and detection schemes of spin-currents at room
temperature, and paves the way for spin-orbitronics in plastic materials.",1511.07848v1
2012-10-09,Spectral Characteristics of the Microwave Emission by the Spin Hall Nano-Oscillator,"We utilized microwave spectroscopy to study the magnetization oscillations
locally induced in a Permalloy film by a pure spin current, which is generated
due to the spin Hall effect in an adjacent Pt layer. The oscillation frequency
is lower than the ferromagnetic resonance of Permalloy, indicating that the
oscillation forms a self-localized nonpropagating spin-wave soliton. At
cryogenic temperatures, the spectral characteristics are remarkably similar to
the traditional spin-torque nano-oscillators driven by spin-polarized currents.
However, the linewidth of the oscillation increases exponentially with
temperature and an additional peak appears in the spectrum below the
ferromagnetic resonance, suggesting that the spectral characteristics are
determined by interplay between two localized dynamical states.",1210.2758v2
2016-07-16,Measurement of spin pumping voltage separated from extrinsic microwave effects,"Conversions between spin and charge currents are core technologies in recent
spintronics. In this article, we provide methods for estimating inverse spin
Hall effects (ISHEs) induced by using microwave-driven spin pumping (SP) as a
spin-current generator. ISHE and SP induce an electromotive force at the
ferromagnetic or spin-wave resonance, which offers a valuable electric way to
study spin physics in materials. At the resonance, a microwave for exciting the
magnetization dynamics induces an additional electromotive force via rf-current
rectification and thermoelectric effects. We discuss methods to separate the
signals generated from such extrinsic microwave effects by controlling sample
structures and configurations. These methods are helpful in performing accurate
measurements on ISHE induced by SP, enabling quantitative studies on the
conversion between spin and charge currents on various kinds of materials.",1607.04716v1
2016-11-15,Spin-Valley Beam Splitter in Graphene,"The fourfold spin-valley degenerate degrees of freedom in bulk graphene can
support rich physics and novel applications associated with multicomponent
quantum Hall effects and linear conductance filtering. In this work, we study
how to break the spin-valley degeneracy of electron beams spatially. We propose
a spin-valley beam splitter in a gated ferromagnetic/pristine/strained graphene
structure. We demonstrate that, in a full resonant tunneling regime for all
spin-valley beam components, the formation of quasi-standing waves can lead
four giant lateral Goos-H\""{a}nchen shifts as large as the transverse beam
width, while the interplay of the two modulated regions can lead difference of
resonant angles or energies for the four spin-valley flavors, manifesting an
effective spin-valley beam splitting effect. The beam splitting effect is found
to be controllable by the gating and strain.",1611.04722v1
2022-10-23,Tidally excited gravity waves in the cores of solar-type stars: resonances and critical-layer formation,"We simulate the propagation and dissipation of tidally induced nonlinear
gravity waves in the cores of solar-type stars. We perform hydrodynamical
simulations of a previously developed Boussinesq model using a spectral-element
code to study the stellar core as a wave cavity that is periodically forced at
the outer boundary with a given azimuthal wavenumber and an adjustable
frequency. For low-amplitude forcing, the system exhibits resonances with
standing g-modes at particular frequencies, corresponding to a situation in
which the tidal torque is highly frequency-dependent. For high-amplitude
forcing, the excited waves break promptly near the centre and spin up the core
so that subsequent waves are absorbed in an expanding critical layer, as found
in previous work, leading to a tidal torque with a smooth frequency-dependence.
For intermediate-amplitude forcing, we find that linear damping of the waves
gradually spins up the core such that the resonance condition can be altered
drastically. The system can evolve towards or away from g-mode resonances,
depending on the difference between the forcing frequency and the closest
eigenfrequency. Eventually, a critical layer forms and absorbs the incoming
waves, leading to a situation similar to the high-amplitude case in which the
waves break promptly. We study the dependence of this process on the forcing
amplitude and frequency, as well as on the diffusion coefficients. We emphasize
that the small Prandtl number in the centre of solar-like stars facilitates the
development of a differentially rotating core owing to the nonlinear feedback
of waves. Our simulations and analysis reveal that this important mechanism may
drastically change the phase of gravity waves and thus the classical picture of
resonance locking in solar-type stars needs to be revised.",2210.12880v2
2015-03-20,Frequency stabilization of the non resonant wave of a continuous-wave singly resonant optical parametric oscillator,"We present an experimental technique allowing to stabilize the frequency of
the non resonant wave in a singly resonant optical parametric oscillator (SRO)
down to the kHz level, much below the pump frequency noise level. By comparing
the frequency of the non resonant wave with a reference cavity, the pump
frequency noise is imposed to the frequency of the resonant wave, and is thus
subtracted from the frequency of the non resonant wave. This permits the non
resonant wave obtained from such a SRO to be simultaneously powerful and
frequency stable, which is usually impossible to obtain when the resonant wave
frequency is stabilized.",1503.06138v1
2001-12-24,Paramagnetic and antiferromagnetic resonances in the diamagnetically diluted Haldane magnet PbNi2V2O8,"The impurity-induced antiferromagnetic ordering of the doped Haldane magnet
Pb(Ni{1-x}Mg{x})2V2O8 (0 < x <0.06) was studied by electron spin resonance
(ESR) on ceramic samples in the frequency range 9-110 GHz. Below the N\'{e}el
temperature a transformation of the ESR spectrum was found, indicating an
antiferromagnetic resonance mode of spin precession. The excitation gap of the
spin-wave spectrum increases with increasing Mg-concentration $x$ in the same
manner as the N\'{e}el temperature, reaching its maximum value of 80 GHz at x >
0.04. At small concentrations x < 0.02 the signals of antiferromagnetic
resonance were found to coexist with the signal of the paramagnetic resonance
indicating a microscopic separation of the magnetic phases.",0112443v1
2020-10-29,Atomic spin-wave control and spin-dependent kicks with shaped subnanosecond pulses,"The absorption of traveling photons resonant with electric dipole transitions
of an atomic gas naturally leads to electric dipole spin wave excitations. For
a number of applications, it would be highly desirable to shape and coherently
control the spatial waveform of the spin waves before spontaneous emission can
occur. This paper details a recently developed optical control technique to
achieve this goal, where counter-propagating, shaped sub-nanosecond pulses
impart sub-wavelength geometric phases to the spin waves by cyclically driving
an auxiliary transition. In particular, we apply this technique to reversibly
shift the wave vector of a spin wave on the $D2$ line of laser-cooled $^{87}$Rb
atoms, by driving an auxiliary $D1$ transition with shape-optimized pulses, so
as to shut off and recall superradiance on demand. We investigate a
spin-dependent momentum transfer during the spin-wave control process, which
leads to a transient optical force as large as $\sim 1\hbar k$/ns, and study
the limitations to the achieved $70\sim 75\%$ spin wave control efficiency by
jointly characterizing the spin-wave control and matterwave acceleration. Aided
by numerical modeling, we project potential future improvements of the control
fidelity to the $99\%$ level when the atomic states are better prepared and by
equipping a faster and more powerful pulse shaper. Our technique also enables a
background-free measurement of the superradiant emission to unveil the precise
scaling of the emission intensity and decay rate with optical depth.",2010.16066v2
2004-02-09,Spin Waves in Striped Phases,"In many antiferromagnetic, quasi-two-dimensional materials, doping with holes
leads to ""stripe"" phases, in which the holes congregate along antiphase domain
walls in the otherwise antiferromagnetic texture. Using a suitably parametrized
two-dimensional Heisenberg model on a square lattice, we study the spin wave
spectra of well-ordered spin stripes, comparing bond-centered antiphase domain
walls to site-centered antiphase domain walls for a range of spacings between
the stripes and for stripes both aligned with the lattice (""vertical"") and
oriented along the diagonals of the lattice (""diagonal""). Our results establish
that there are qualitative differences between the expected neutron scattering
responses for the bond-centered and site-centered cases. In particular,
bond-centered stripes of odd spacing generically exhibit more elastic peaks
than their site-centered counterparts. For inelastic scattering, we find that
bond-centered stripes produce more spin wave bands than site-centered stripes
of the same spacing and that bond-centered stripes produce rather isotropic low
energy spin wave cones for a large range of parameters, despite local
microscopic anisotropy. We find that extra scattering intensity due to the
crossing of spin wave modes (which may be linked to the ""resonance peak"" in the
cuprates) is more likely for diagonal stripes, whether site- or bond-centered,
whereas spin wave bands generically repel, rather than cross, when stripes are
vertical.",0402231v2
2015-10-14,Angstrom-resolution magnetic resonance imaging of single molecules via wavefunction fingerprints of nuclear spins,"Single-molecule sensitivity of nuclear magnetic resonance (NMR) and angstrom
resolution of magnetic resonance imaging (MRI) are the highest challenges in
magnetic microscopy. Recent development in dynamical-decoupling- (DD) enhanced
diamond quantum sensing has enabled single-nucleus NMR and nanoscale NMR.
Similar to conventional NMR and MRI, current DD-based quantum sensing utilizes
the frequency fingerprints of target nuclear spins. The frequency fingerprints
by their nature cannot resolve different nuclear spins that have the same noise
frequency or differentiate different types of correlations in nuclear-spin
clusters, which limit the resolution of single-molecule MRI. Here we show that
this limitation can be overcome by using wave-function fingerprints of target
nuclear spins, which is much more sensitive than the frequency fingerprints to
the weak hyperfine interaction between the targets and a sensor under resonant
DD control. We demonstrate a scheme of angstrom-resolution MRI that is capable
of counting and individually localizing single nuclear spins of the same
frequency and characterizing the correlations in nuclear-spin clusters. A
nitrogen-vacancy-center spin sensor near a diamond surface, provided that the
coherence time is improved by surface engineering in the near future, may be
employed to determine with angstrom resolution the positions and conformation
of single molecules that are isotope labeled. The scheme in this work offers an
approach to breaking the resolution limit set by the frequency gradients in
conventional MRI and to reaching the angstrom-scale resolution.",1510.04081v3
2017-02-13,"Lieb and hole-doped ferrimagnetism, spiral, resonating valence-bond states, and phase separation in large-U $AB_{2}$ Hubbard chains","The ground state (GS) properties of the quasi-one-dimensional $AB_2$ Hubbard
model are investigated taking the effects of charge and spin quantum
fluctuations on equal footing. In the strong-coupling regime, we derive a
low-energy Lagrangian suitable to describe the ferrimagnetic phase at half
filling and the phases in the hole-doped regime. At half filling, a
perturbative spin-wave analysis allows us to find the GS energy, sublattice
magnetizations, and Lieb total spin per unit cell of the effective quantum
Heisenberg model, in very good agreement with previous results. In the
challenging hole doping regime away from half filling, we derive the
corresponding $t\textrm{-}J$ Hamiltonian. Under the assumption that charge and
spin quantum correlations are decoupled, the evolution of the second-order
spin-wave modes in the doped regime unveils the occurrence of spatially
modulated spin structures and the emergence of phase separation in the presence
of resonating-valence-bond states. We also calculate the doping-dependent GS
energy and total spin per unit cell, in which case it is shown that the spiral
ferrimagnetic order collapses at a critical hole concentration. Notably, our
analytical results in the doped regime are in very good agreement with density
matrix renormalization group studies, where our assumption of spin-charge
decoupling is numerically supported by the formation of charge-density waves in
anti-phase with the modulation of the magnetic structure.",1702.03609v4
2006-08-21,Driven coherent oscillations of a single electron spin in a quantum dot,"The ability to control the quantum state of a single electron spin in a
quantum dot is at the heart of recent developments towards a scalable
spin-based quantum computer. In combination with the recently demonstrated
exchange gate between two neighbouring spins, driven coherent single spin
rotations would permit universal quantum operations. Here, we report the
experimental realization of single electron spin rotations in a double quantum
dot. First, we apply a continuous-wave oscillating magnetic field, generated
on-chip, and observe electron spin resonance in spin-dependent transport
measurements through the two dots. Next, we coherently control the quantum
state of the electron spin by applying short bursts of the oscillating magnetic
field and observe about eight oscillations of the spin state (so-called Rabi
oscillations) during a microsecond burst. These results demonstrate the
feasibility of operating single-electron spins in a quantum dot as quantum
bits.",0608459v1
2015-06-02,Nonlocal Magnetoresistance Mediated by Spin Superfluidity,"The electrical response of two diffusive metals is studied when they are
linked by a magnetic insulator hosting a topologically stable (superfluid) spin
current. We discuss how charge currents in the metals induce a spin
supercurrent state, which in turn generates a magnetoresistance that depends on
the topology of the electrical circuit. This magnetoresistance relies on phase
coherence over the entire magnet and gives direct evidence for spin
superfluidity. We show that driving the magnet with an ac current allows
coherent spin transport even in the presence of U(1)-breaking magnetic
anisotropy that can preclude dc superfluid transport. Spin transmission in the
ac regime shows a series of resonance peaks as a function of frequency. The
peak locations, heights, and widths can be used to extract static interfacial
properties, e.g., the spin-mixing conductance and effective spin Hall angle,
and to probe dynamic properties such as the spin-wave dispersion. Thus, ac
transport may provide a simpler route to realizing nonequilbrium coherent spin
transport and a useful way to characterize the magnetic system, serving as a
precursor to the realization of dc superfluid spin transport.",1506.01059v2
2008-01-23,Observations of time delayed all-optical routing in a slow light regime,"We report an observation of a delayed all-optical routing/switching
phenomenon based on ultraslow group velocity of light via nondegenerate
four-wave mixing processes in a defected solid medium. Unlike previous
demonstrations of enhanced four-wave mixing processes using the slow light
effects, the present observation demonstrates a direct retrieval of the
resonant Raman-pulse excited spin coherence into photon coherence through
coherence conversion processes.",0801.3501v1
2008-12-18,Macroscopic quantum effects generated by the acoustic wave in a molecular magnet,"We have shown that the size of the magnetization step due to resonant spin
tunneling in a molecular magnet can be strongly affected by sound. The
transverse acoustic wave can also generate macroscopic quantum beats of the
magnetization during the field sweep.",0812.3590v1
2021-11-04,Control of the phase of reflected spin-waves from magnonic Gires-Tournois interferometer of subwavelength width,"The phase is one of the fundamental properties of a wave that allows to
control interference effects and can be used to efficiently encode information.
We examine numerically a magnonic resonator of the Gires-Tournois
interferometer type, which enables the control of the phase of spin waves
reflected from the edges of the ferromagnetic film. The considered
interferometer consists of a Py thin film and a thin, narrow Py stripe placed
above its edge, both coupled magnetostatically. We show that the resonances and
the phase of the reflected spin waves are sensitive for a variation of the
geometrical parameters of this bi-layerd part of the system. The high
sensitivity to film, stripe, and non-magnetic spacer thicknesses, offers a
prospect for developing magnonic metasurfaces and sensors.",2111.02678v1
2004-09-07,Spin-Orbit Resonance and the Evolution of Compact Binary Systems,"Starting with a post-Newtonian description of compact binary systems, we
derive a set of equations that describes the evolution of the orbital angular
momentum and both spin vectors during inspiral. We find regions of phase space
that exhibit resonance behavior, characterized by small librations of the spin
vectors around a fixed orientation. Due to the loss of energy and orbital
angular momentum through radiation reaction, systems can eventually be captured
into these resonance orientations. By investigating the long-term evolution of
compact binaries with a variety of initial conditions, we find that the
distribution in parameter space can be strongly affected by resonance captures.
This has the effect of significantly reducing the size of search space for
gravitational wave sources, in turn improving the chances of detecting such
sources through methods of template matching. Furthermore, by calculating the
expected spin distribution at the end of the inspiral phase, we can predict
what are the most likely initial conditions for the plunge phase, a result of
great interest for numerical relativity calculations.",0409174v1
2004-06-24,Resonant magnetic X-ray scattering spectra in SDW Cr -- ab initio study -----,"Using ab-initio band structure calculation based on the local density
approximation, Cr K-edge resonant X-ray magnetic scattering spectra are
analyzed in the spin density wave (SDW) state of chromium. We perform band
structure calculation, assuming an ideal bcc lattice structure with the lattice
constant observed at the spin-flip temperature T_{SF} and a commensurate SDW
state with the propagation vector close to the observed value at T_{SF}. Taking
account of the spin-orbit interaction, we obtain the orbital moment on each Cr
site induced in proportion to the local spin moment, which is quite small, at
most a tenth of those in nickel or iron. In spite of the tiny 3d orbital
moment, the orbital polarization is found to have large fluctuations as a
function of energy. We obtain the scattering intensity at the Cr K-edge on the
SDW magnetic Bragg spot, which shows resonant enhancement in good agreement
with the experiment. The 3d orbital polarization is found to be highly
correlated with the intensity of the resonant main peak, indicating that the 4p
orbital polarization is mainly induced by the 3d orbital polarization through
the p-d hybridization.",0406576v1
2020-12-01,Nonreciprocal optical solitons in a spinning Kerr resonator,"We propose a spinning nonlinear resonator as an experimentally accessible
platform to achieve nonreciprocal control of optical solitons. Nonreciprocity
here results from the relativistic Sagnac-Fizeau optical drag effect, which is
different for pump fields propagating in the spinning direction or in the
direction opposite to it. We show that in a spinning Kerr resonator, different
soliton states appear for the input fields in different directions. These
nonreciprocal solitons are more stable against losses induced by inter-modal
coupling between clockwise and counterclockwise modes of the resonator. Our
work builds a bridge between nonreciprocal physics and soliton science,
providing a promising route towards achieving soliton-wave optical isolators
and one-way soliton communications.",2012.00225v4
2004-08-17,Collective Spin-Density-Wave Response Perpendicular to the Chains of the Quasi One-Dimensional Conductor (TMTSF)2PF6,"Microwave experiments along all three directions of the spin-density-wave
model compound (TMTSF)$_2$PF$_6$ reveal that the pinned mode resonance is
present along the $a$ and $b^{\prime}$ axes. The collective transport is
considered to be the fingerprint of the condensate. In contrast to common quasi
one-dimensional models, the density wave also slides in the perpendicular
$b^{\prime}$ direction. The collective response is absent along the least
conducting $c^*$ direction.",0408382v1
2007-04-11,On the existence of chaotic circumferential waves in spinning disks,"We use a third-order perturbation theory and Melnikov's method to prove the
existence of chaos in spinning circular disks subject to a lateral point load.
We show that the emergence of transverse homoclinic and heteroclinic points
respectively lead to a random reversal in the traveling direction of
circumferential waves and a random phase shift of magnitude $\pi$ for both
forward and backward wave components. These long-term phenomena occur in
imperfect low-speed disks sufficiently far from fundamental resonances.",0704.1406v1
2022-05-11,Chiral standing spin waves in skyrmion lattice,"This work studies the resonance excitations of the three-dimensional
skyrmions lattice in the finite thickness plate of an isotropic chiral magnet
using spin dynamics simulations. We found that the absorption spectra and
resonance modes differ from those predicted by the two-dimensional model and
the model of the unconfined bulk crystal. The features observed on the spectra
can be explained by the formation of chiral standing spin waves, which,
contrary to conventional standing spin waves, are characterized by the helical
profile of dynamic magnetization of fixed chirality defined by the
Dzyaloshinskii-Moriya interaction. In this case, the dynamic susceptibility
becomes a function of the plate thickness, which gives rise to an interesting
effect that manifests itself in periodical fading of the intensity of
corresponding modes and makes excitation of these modes impossible at specific
thicknesses.",2205.05466v1
2009-12-16,Coupling of spin and orbital excitations in the iron-based superconductor FeSe(0.5)Te(0.5),"We present a combined analysis of neutron scattering and photoemission
measurements on superconducting FeSe(0.5)Te(0.5). The low-energy magnetic
excitations disperse only in the direction transverse to the characteristic
wave vector (1/2,0,0), whereas the electronic Fermi surface near (1/2,0,0)
appears to consist of four incommensurate pockets. While the spin resonance
occurs at an incommensurate wave vector compatible with nesting, neither
spin-wave nor Fermi-surface-nesting models can describe the magnetic
dispersion. We propose that a coupling of spin and orbital correlations is key
to explaining this behavior. If correct, it follows that these nematic
fluctuations are involved in the resonance and could be relevant to the pairing
mechanism.",0912.3205v2
2005-02-23,Unified approach to photo and electro-production of mesons with arbitrary spins,"A new approach to identify the independent amplitudes along with their
partial wave multipole expansions, for photo and electro-production is
suggested,which is generally applicable to mesons with arbitrary spin-parity.
These amplitudes facilitate direct identification of different resonance
contributions.",0502073v2
2005-06-23,A short note on climbing gravity improbable: Superradiant ring fellowship of launching the high Lorentz-factor outflows/jets,"The spin energy extraction from a rotating black hole by amplification of
scalar waves inside superradiance resonance wedge cavity (ring), followed by
jet formation via magnetic reconnection assisted by the amplified scalar
fields, is proposed. This mechanism may explain the availability of energy for
as well as the formation of relativistic jets with high Lorentz-factor in
microquasars and quasars. It is speculated that it may also explain that the
spin of the central black hole, which facilitates the formation of
superradiance cavity, which in turn would produce the amplified scalar waves by
taking the hole's spin energy, is the source for the distinction between
radio-loud and radio-quiet active galaxies.",0506557v1
1998-04-06,Helical spin-density wave in doped V2O3,"Recent neutron scattering and nuclear magnetic resonance experiments have
revealed that the low temperature phase of doped V_{2-y}O_3 is an itinerant
antiferromagnet with a helical spin structure. We use a band structure
calculation as the point of departure to show that these experiments are in
agreement with mean field results for an Overhauser spin-density wave state.
The influences of a finite life-time and of dilute magnetic impurities are
discussed.",9804052v1
2007-10-19,Paramagnonlike excitations and spin diffusion in magnetic resonance studies of copper oxide superconductors,"The relaxation function theory for a doped two-dimensional Heisenberg
antiferromagnetic system in the paramagnetic state for all wave vectors through
the Brillouin zone is presented in view of low frequency response of high-$T_c$
copper oxide superconductors. We deduced the regions of long lifetime [$T
\lesssim 400(1-4x)$ K] and ""overdamped"" [$T \gtrsim 700(1-4x)$ K]
paramagnonlike excitations in the temperature ($T$)-doping index ($x$) phase
diagram from plane oxygen nuclear spin-lattice relaxation rate $^{17}(1/T_1)$
data in up to optimally doped La$_{2-x}$Sr$_{x}$CuO$_{4}$ thus providing the
regimes for the spin wave concept and the ''overdamped'' mode.",0710.3615v1
2013-03-12,Thermally excited spin waves in a nano-structure: thermal gradient vs. constant temperature,"Using micromagnetic simulations, we have investigated spin dynamics in a
nanostructure in the presence of thermal fluctuations. In particular, we have
studied the effects of a uniform temperature and of a uniform thermal gradient.
In both cases, the stochastic field leads to an increase of the precession
angle of the magnetization, and to a mild decreas of the linewidth of the
resonance peaks. Our results indicate that the Gilbert damping parameter plays
the role of control parameter for the amplification of spin waves.",1303.2895v1
2021-04-27,Field-driven dynamics of magnetic Hopfions,"We present micromagnetic simulations on resonant spin wave modes of magnetic
Hopfions up to 15 GHz driven by external magnetic fields. A sharp transition is
found around 32 mT coinciding with a transition from Hopfions to magnetic
torons. The modes exhibit characteristic amplitudes in frequency space
accompanied by unique localization patterns in real space, and are found to be
robust to damping around topological features, particularly vortex lines in
Hopfions and Bloch points in torons. The marked differences in spin wave
spectra between Hopfions, torons and target skyrmions can serve as fingerprints
in future experimental validation studies of these novel 3d topological spin
textures.",2104.13349v1
2017-10-25,Co- and contra-directional vertical coupling between ferromagnetic layers with grating for short-wavelength spin wave generation,"The possibility to generate short spin waves is of great interest in the
field of magnonics nowadays. We present an effective and technically affordable
way of conversion of long spin waves, which may be generated by conventional
microwave antenna, to the short, sub-micrometer waves. It is achieved by
grating-assisted resonant dynamic dipolar interaction between two ferromagnetic
layers separated by some distance. We analyze criteria for the optimal
conversion giving a semi-analytical approach for the coupling coefficient. We
show by the numerical calculations the efficient energy transfer between layers
which may be either of co-directional or contra-directional type. Such a system
may operate either as a short spin wave generator or a frequency filter, moving
foreward possible application of magnonics.",1710.09138v1
2021-04-22,Bistable nanomagnet as programmable phase inverter for spin waves,"To realize spin wave logic gates programmable phase inverters are essential.
We image with phase-resolved Brillouin light scattering microscopy propagating
spin waves in a one-dimensional magnonic crystal consisting of dipolarly
coupled magnetic nanostripes. We demonstrate phase shifts upon a single
nanostripe of opposed magnetization. Using micromagnetic simulations we model
our experimental finding in a wide parameter space of bias fields and wave
vectors. We find that low-loss phase inversion is achieved, when the internal
field of the oppositely magnetized nanostripe is tuned such that the latter
supports a resonant standing spin wave mode with odd quantization number at the
given frequency. Our results are key for the realization of phase inverters
with optimized signal transmission.",2104.11015v1
2008-12-01,Antiferromagnet-based nuclear spin model of scalable quantum register with inhomogeneous magnetic field,"As a nuclear spin model of scalable quantum register, the one-dimensional
chain of the magnetic atoms with nuclear spins 1/2 substituting the basic atoms
in the plate of nuclear spin free easy-axis 3D antiferromagnet is considered.
It is formulated the generalized antiferromagnet Hamiltonian in spin-wave
approximation (low temperatures) considering the inhomogeneous external
magnetic field, which is directed along the easy axis normally to plane of the
plate and has a constant gradient along the nuclear spin chain. Assuming a weak
gradient, the asymptotic expression for coefficients of unitary transformations
to the diagonal form of antiferromagnet Hamiltonian is found. With this result
the expression for indirect interspin coupling, which is due to hyperfine
nuclear electron coupling in atoms and the virtual spin wave propagation in
antiferromagnet ground state, was evaluated.
  It is shown that the inhomogeneous magnetic field essentially modifies the
characteristics of indirect interspin coupling. The indirect interaction
essentially grows and even oscillates in relation to the interspin distance
when the local field value in the middle point of two considered nuclear spin
is close to the critical field for quantum phase transition of spin-flop type
in bulk antiferromagnet or close to antiferromagnetic resonance. Thus, the
external magnetic field, its gradient, microwave frequency and power can play
the role of control parameters for qubit states.
  Finally, the one and two qubit states decoherence and longitudinal relaxation
rate are caused by the interaction of nuclear spins with virtual spin waves in
antiferromagnet ground state are calculated.",0812.0135v1
2021-05-24,Cavity magnomechanics with surface acoustic waves,"Magnons, namely spin waves, are collective spin excitations in ferromagnets,
and their control through coupling with other excitations is a key technology
for future hybrid spintronic devices. Although strong coupling has been
demonstrated with microwave photonic structures, an alternative approach
permitting high density integration and minimized electromagnetic crosstalk is
required. Here we report a planar cavity magnomechanical system, where the
cavity of surface acoustic waves enhances the spatial and spectral power
density to thus implement magnon-phonon coupling at room temperature.
Excitation of spin-wave resonance involves significant acoustic power
absorption, whereas the collective spin motion reversely exerts a back-action
force on the cavity dynamics. The cavity frequency and quality-factor are
significantly modified by the back-action effect, and the resultant
cooperativity exceeds unity, suggesting coherent interaction between magnons
and phonons. The demonstration of a chip-scale magnomechanical system paves the
way to the development of novel spin-acoustic technologies for classical and
quantum applications.",2105.11127v1
2015-12-16,"On the existence conditions of surface spin wave modes in (Ga,Mn)As thin films","Spin-wave resonance (SWR) is a newly emerged method for studying surface
magnetic anisotropy and surface spin-wave modes (SSWMs) in (Ga,Mn)As thin
films. The existence of SSWMs in (Ga,Mn)As thin films has recently been
reported in the literature; SSWMs have been observed in the in-plane
configuration (with variable azimuth angle $\phi_M$ between the in-plane
magnetization of the film and the surface [100] crystal axis), in the azimuth
angle range between two in-plane critical angles $\phi_{c1}$ and $\phi_{c2}$.
We show here that cubic surface anisotropy is an essential factor determining
the existence conditions of the above-mentioned SSWMs: conditions favorable for
the occurrence of surface spin-wave modes in a (Ga,Mn)As thin film in the
in-plane configuration are fulfilled for those azimuth orientations of the
magnetization of the sample that lie around the hard axes of cubic magnetic
anisotropy. This implies that a hard cubic anisotropy axis can be regarded in
(Ga,Mn)As thin films as an easy axis for surface spin pinning.",1512.05140v1
2016-04-05,Homodyne-detected ferromagnetic resonance of in-plane magnetized nano-contacts: composite spin wave resonances and their excitation mechanism,"This work provides a detailed investigation of the measured in-plane
field-swept homodyne-detected ferromagnetic resonance (FMR) spectra of an
extended Co/Cu/NiFe pseudo spin valve stack using a nanocontact (NC) geometry.
The magnetodynamics are generated by a pulse-modulated microwave current and
the resulting rectified dc mixing voltage, which appears across the NC at
resonance, is detected using a lock-in amplifier. Most notably, we find that
the measured spectra of the NiFe layer are composite in nature and highly
asymmetric, consistent with the broadband excitation of multiple modes.
Additionally, the data must be fit with two Lorentzian functions in order to
extract a reasonable value for the Gilbert damping of the NiFe. Aided by
micromagnetic simulations, we conclude that (i) for in-plane fields the rf
Oersted field in the vicinity of the NC plays the dominant role in generating
the observed spectra, (ii) in addition to the FMR mode, exchange dominated spin
waves are also generated, and (iii) the NC diameter sets the mean wavevector of
the exchange dominated spin wave, in good agreement with the dispersion
relation.",1604.01389v1
2019-11-01,Growth of resonances and chaos for a spinning test particle in the Schwarzschild background,"Inspirals of stellar mass compact objects into supermassive black holes are
known as extreme mass ratio inspirals. In the simplest approximation, the
motion of the compact object is modeled as a geodesic in the space-time of the
massive black hole with the orbit decaying due to radiated energy and angular
momentum, thus yielding a highly regular inspiral. However, once the spin of
the secondary compact body is taken into account, integrability is broken and
prolonged resonances along with chaotic motion appear.
  We numerically integrate the motion of a spinning test body in the field of a
non-spinning black hole and analyse it using various methods. We show for the
first time that resonances and chaos can be found even for astrophysical values
of spin. On the other hand, we devise a method to analyse the growth of the
resonances, and we conclude that the resonances we observe are only caused by
terms quadratic in spin and will generally stay very small in the
small-mass-ratio limit. Last but not least, we compute gravitational waveforms
by solving numerically the Teukolsky equations in the time-domain and establish
that they carry information on the motion's dynamics. In particular, we show
that the time series of the gravitational wave strain can be used to discern
regular from chaotic motion of the source.",1911.00414v1
2004-10-01,Modeling and Simulations of a Single-Spin Measurement using MRFM,"We review the quantum theory of a single spin magnetic resonance force
microscopy (MRFM). We concentrate on the novel technique called oscillating
cantilever-driven adiabatic reversals (OSCAR), which has been used for a single
spin detection (Dan Rugar, Talk on the 2004 IEEE NTC Quantum Device Technology
Workshop). First we describe the quantum dynamics of the cantilever-spin system
using simple estimates in the spirit of the mean field approximation. Then we
present the results of our computer simulations of the Schrodinger equation for
the wave function of the cantilever-spin system and of the master equation for
the density matrix of the system. We demonstrate that the cantilever behaves
like a quasi-classical measurement device which detects the spin projection
along the effective magnetic field. We show that the OSCAR technique provides
continuous monitoring of the single spin, which could be used to detect the
mysterious quantum collapses of the wave function of the cantilever-spin
system.",0410002v1
2022-06-10,Observing high-k magnons with Mie-resonance-enhanced Brillouin light scattering,"Magnonics is a prospective beyond CMOS technology which uses magnons, the
quanta of spin waves, for low-power information processing. Many magnonic
concepts and devices were recently demonstrated at macro- and microscale, and
now these concepts need to be realized at nanoscale. Brillouin light scattering
spectroscopy and microscopy (BLS) has become a standard technique for spin wave
visualization and characterization, and enabled many pioneering magnonic
experiments. However, due to its fundamental limit in maximum detectable magnon
momentum, the conventional BLS cannot be used to detect nanoscale spin waves.
Here we show that optically induced Mie resonances in dielectric nanoparticles
can be used to extend the range of accessible spin wave wavevectors beyond the
BLS fundamental limit. The method is universal and can be used in many magnonic
experiments dealing with thermally excited as well as coherently excited
high-momentum, short-wavelength spin waves. This discovery significantly
extends the usability and relevance of the BLS technique for nanoscale magnonic
research.",2206.05178v3
2019-09-27,Type II $t-J$ model in superconducting nickelate Nd$_{1-x}$Sr$_x$NiO$_2$,"The recent observation of superconductivity at relatively high temperatures
in hole doped NdNiO$_2$ has generated considerable interest, particularly due
to its similarity with the infinite layer cuprates. Building on the observation
that the Ni$^{2+}$ ions resulting from hole doping are commonly found in the
spin-triplet state, we introduce and study a variant of the $t-J$ model in
which the holes carry S=1. We name this new model the Type II $t-J$ model. We
find two distinct mechanisms for $d$ wave superconductivity. In both scenarios
the pairing is driven by the spin coupling $J$. However, coherence is gained in
distinct ways in these two scenarios. In the first case, the spin-one holes
condense leading to a $d$ wave superconductor along with spin-symmetry
breaking. Different orders including spin-nematic orders are possible. This
scenario is captured by a spin one slave boson theory. In the second scenario,
a coherent and symmetric $d$ wave superconductor is achieved from ""Kondo
resonance"": spin one holes contribute two electrons to form large Fermi surface
together with the spin 1/2 singly occupied sites. The large Fermi surface then
undergoes $d$ wave pairing because of spin coupling $J$, similar to heavy
fermion superconductor. We propose a three-fermion parton theory to treat these
two different scenarios in one unified framework and calculate its doping phase
diagram within a self consistent mean field approximation. Our study shows that
a combination of ""cuprate physics"" and ""heavy fermion physics"" may emerge in
the type II $t-J$ model.",1909.12865v2
2019-01-25,Axisymmetric density waves in Saturn's rings,"Density waves in Saturn's rings are usually tightly wrapped spiral patterns
generated by resonances with either Saturn's moons or structures inside the
planet. However, between the Barnard and Bessel Gaps in the Cassini Division
(i.e. between 120,240 and 120,300 km from Saturn's spin axis), there are
density variations that appear to form an axisymmetric density wave consisting
of concentric zones of varying densities that propagate radially through the
rings. Axisymmetric waves cannot be generated directly by a satellite
resonance, but instead appear to be excited by interference between a nearby
satellite resonance and normal mode oscillations on the inner edge of the
Barnard Gap. Similar axisymmetric waves may exist just interior to other
resonantly confined edges that exhibit a large number of normal modes,
including the Dawes ringlet in the outer C ring and the outermost part of the B
ring.",1901.09104v1
2016-01-13,Magnetic fluctuations in pair density wave superconductors,"Pair density wave superconductivity constitutes a novel electronic condensate
proposed to be realized in certain unconventional superconductors. Establishing
its potential existence is important for our fundamental understanding of
superconductivity in correlated materials. Here we compute the dynamical
magnetic susceptibility in the presence of a pair density wave ordered state,
and study its fingerprints on the spin-wave spectrum including the neutron
resonance. In contrast to the standard case of d-wave superconductivity, we
show that the pair density wave phase exhibits neither a spin-gap nor a
magnetic resonance peak, in agreement with a recent neutron scattering
experiment on underdoped La$_{1.905}$Ba$_{0.095}$CuO$_4$ [Z. Xu et al., Phys.
Rev. Lett. 113, 177002 (2014)].",1601.03251v2
2003-05-19,The anapole moments in disk-form MS-wave ferrite particle,"The anapole moments describe the parity-violating parity-odd,
time-reversal-even couplings between elementary particles and the
electromagnetic (EM) field. Surprisingly, the anapole-like moment properties
can be found in certain artificially engineered physical systems. In
microwaves, ferrite resonators with multi-resonance magnetostatic-wave
(MS-wave) oscillations may have sizes two-four orders less than the free-space
EM wavelength at the same frequency. MS-wave oscillations in a ferrite sample
occupy a special place between the pure electromagnetic and spin-wave
(exchange) processes. The energy density of MS-wave oscillations is not the
electromagnetic-wave density of energy and not the exchange energy density as
well. These microscopic oscillating objects -- the particles -- may interact
with the external EM fields by a very specific way, forbidden for the classical
description. To describe such interactions, the quantum mechanical analysis
should be used. The presence of surface magnetic currents is one of the
features of MS oscillations in a normally magnetized ferrite disk resonator.
Because of such magnetic currents, MS oscillations in ferrite disk resonators
become parity violating. The parity-violating couplings between disk-form
ferrite particles and the external EM field should be analyzed based on the
notion of an anapole moment.",0305431v1
2010-04-26,Spin density wave in oxypnictide superconductors in a three-band model,"The spin density wave and its temperature dependence in oxypnictide are
studied in a three-band model. The spin susceptibilities with various
interactions are calculated in the random phase approximation(PPA). It is found
that the spin susceptibility peaks around the M point show a spin density
wave(SDW) with momentum (0, $\pi$) and a clear stripe-like spin configuration.
The intra-band Coulomb repulsion enhances remarkably the SDW but the Hund's
coupling weakens it. It is shown that a new resonance appears at higher
temperatures at the $\Gamma$ point indicating the formation of a paramagnetic
phase. There is a clear transition from the SDW phase to the paramagnetic
phase.",1004.4570v1
2013-12-04,Magnetic excitation in resonant inelastic x-ray scattering of Sr$_2$IrO$_4$: A localized spin picture,"We study the magnetic excitations in 5d transition-metal oxide Sr$_2$IrO$_4$
on the basis of the Heisenberg model with small anisotropic terms on a square
lattice. We calculate the correlation functions by using the Green's functions
in the spin-wave approximation. The spin waves are split into two modes with
slightly different energies due to the anisotropic terms. It is shown that the
spin correlation functions of the y and z components are composed of a single
peak corresponding to each mode. We analyze the process of resonant inelastic
x-ray scattering (RIXS) without relying on the fast collision approximation to
obtain the local scattering operator. The RIXS intensity is derived as a sum of
the correlation functions of the y and z spin components. We demonstrate that
the RIXS intensity as a function of energy shows two-peak structure brought
about by the two modes, which could be observed in the RIXS experiment.",1312.1071v2
2017-12-07,Spin waves in coupled YIG/Co heterostructures,"We investigate yttrium iron garnet (YIG)/cobalt (Co) heterostructures using
broadband ferromagnetic resonance (FMR). We observe an efficient excitation of
perpendicular standing spin waves (PSSWs) in the YIG layer when the resonance
frequencies of the YIG PSSWs and the Co FMR line coincide. Avoided crossings of
YIG PSSWs and the Co FMR line are found and modeled using mutual spin pumping
and exchange torques. The excitation of PSSWs is suppressed by a thin aluminum
oxide (AlOx) interlayer but persists with a copper (Cu) interlayer, in
agreement with the proposed model.",1712.02561v1
2017-04-30,Angular Dependent Magnetization Dynamics of Kagome Artificial Spin Ice Incorporating Topological Defects,"We report angular-dependent spin-wave spectroscopy on kagome artificial spin
ice made of large arrays of interconnected Ni80Fe20 nanobars. Spectra taken in
saturated and disordered states exhibit a series of resonances with
characteristic in-plane angular dependencies. Micromagnetic simulations allow
us to interpret characteristic resonances of a two-step magnetization reversal
of the nanomagnets. The dynamic properties are consistent with topological
defects that are provoked via a magnetic field applied at specific angles.
Simulations that we performed on previously investigated kagome artificial spin
ice consisting of isolated nanobars show characteristic discrepancies in the
spin wave modes which we explain by the absence of vertices.",1705.00270v1
2009-09-10,Coupling of localized moments and itinerant electrons in EuFe2As2 single crystals studied by Electron Spin Resonance,"Electron spin resonance measurements in EuFe2As2 single crystals revealed an
absorption spectrum of a single resonance with Dysonian lineshape. Above the
spin-density wave transition at T_SDW = 190 K the spectra are isotropic and the
spin relaxation is strongly coupled to the CEs resulting in a Korringa-like
increase of the linewidth. Below T_SDW, a distinct anisotropy develops and the
relaxation behavior of the Eu spins changes drastically into one with
characteristic properties of a magnetic insulating system, where dipolar and
crystal-field interactions dominate. This indicates a spatial confinement of
the conduction electrons to the FeAs layers in the SDW state.",0909.2054v1
2012-02-07,Electrical activation and electron spin resonance measurements of implanted bismuth in isotopically enriched silicon-28,"We have performed continuous wave and pulsed electron spin resonance
measurements of implanted bismuth donors in isotopically enriched silicon-28.
Donors are electrically activated via thermal annealing with minimal diffusion.
Damage from bismuth ion implantation is repaired during thermal annealing as
evidenced by narrow spin resonance linewidths (B_pp=12uT and long spin
coherence times T_2=0.7ms, at temperature T=8K). The results qualify ion
implanted bismuth as a promising candidate for spin qubit integration in
silicon.",1202.1560v2
2012-08-14,Field induced spin exciton doublet splitting in d_{x^2-y^2}-wave 115-heavy electron superconductors,"We investigate the spin-exciton modes in the superconducting d_{x^2-y^2}
state of CeMIn_5 heavy fermion compounds found at the antiferromagnetic wave
vector by inelastic neutron scattering. We present a theoretical model that
explains the field dependence for both field directions. We show that the
recently observed splitting of the spin exciton doublet in CeCoIn_5 into two
non-degenerate modes for in-plane field appears naturally in this model. This
is due to the spin anisotropy of g- factors and quasiparticle interactions
which lead to different resonant conditions for the dynamic susceptibility
components. We predict that the splitting of the spin resonance doublet becomes
strongly nonlinear for larger fields when the energy of both split components
decreases. For field along the tetragonal axis no splitting but only a
broadening of the resonance is found in agreement with experiment.",1208.2897v1
2015-01-14,CW and pulsed electrically detected magnetic resonance spectroscopy at 263 GHz/12 T on operating amorphous silicon solar cells,"Here we describe a new high frequency/high field continuous wave and pulsed
electrically detected magnetic resonance (CW EDMR and pEDMR) setup, operating
at 263 GHz and resonance fields between 0 and 12 T. Spin dependent transport in
illuminated hydrogenated amorphous silicon p-i-n solar cells at 5 K and 90 K
was studied by in operando 263 GHz CW and pEDMR alongside with complementary
X-band CW EDMR. Benefiting from the superior resolution at 263 GHz, we were
able to better resolve EDMR signals originating from spin dependent hopping and
recombination processes. 5 K EDMR spectra were found to be dominated by
conduction and valence band tale states involved in spin dependent hopping,
with additional contributions from triplet exciton states. 90 K EDMR spectra
could be assigned to spin pair recombination involving conduction band tail
states and dangling bonds as dominating spin dependent transport process, with
additional contributions from valence band tail and triplet exciton states.",1501.03485v1
2020-03-25,Two-photon driven magnon-pair resonance as a signature of spin-nematic order,"We theoretically study the nonlinear magnetic resonance driven by intense
laser or electromagnetic wave in a fully polarized frustrated magnet near a
less-visible spin-nematic ordered phase. In general, both magnons and magnon
pairs (two-magnon bound state) appear as the low-energy excitation in the
saturated state of spin-nematic magnets. Their excitation energies are usually
in terahertz (THz) or gigahertz range. Magnon pairs with angular momentum
2$\hbar$ can be excited by the simultaneous absorption of two photons, and such
multi-photon processes occur if the applied THz laser is strong enough. We
compute laser-driven magnetic dynamics of a frustrated four-spin system with
both magnon ($\hbar$) and magnon-pair (2$\hbar$) like excitations which is
analogous to a macroscopic frustrated magnet with a spin nematic phase. We
estimate the required strength of magnetic field of laser for the realization
of two photon absorption, taking into account dissipation effects with the
Lindblad equation. We show that intense THz laser with ac magnetic field of
0.1-1.0 Tesla is enough to observe magnon-pair resonance.",2003.11240v2
2014-05-28,Conditional control of donor nuclear spins in silicon using Stark shifts,"Electric fields can be used to tune donor spins in silicon using the Stark
shift, whereby the donor electron wave function is displaced by an electric
field, modifying the hyperfine coupling between the electron spin and the donor
nuclear spin. We present a technique based on dynamic decoupling of the
electron spin to accurately determine the Stark shift, and illustrate this
using antimony donors in isotopically purified silicon-28. We then demonstrate
two different methods to use a DC electric field combined with an applied
resonant radio-frequency (RF) field to conditionally control donor nuclear
spins. The first method combines an electric-field induced conditional phase
gate with standard RF pulses, and the second one simply detunes the spins
off-resonance. Finally, we consider different strategies to reduce the effect
of electric field inhomogeneities and obtain above 90% process fidelities.",1405.7420v1
2017-03-01,Spin-Momentum Locking in the Near Field of Metal Nanoparticles,"Light carries both spin and momentum. Spin-orbit interactions of light come
into play at the subwavelength scale of nano-optics and nano-photonics, where
they determine the behaviour of light. These phenomena, in which the spin
affects and controls the spatial degrees of freedom of light, are attracting
rapidly growing interest. Here we present results on the spin-momentum locking
in the near field of metal nanostructures supporting localized surface
resonances. These systems can confine light to very small dimensions below the
diffraction limit, leading to a striking near-field enhancement. In contrast to
the propagating evanescent waves of surface plasmon-polariton modes, the
electromagnetic near-field of localized surface resonances does not exhibit a
definite position-independent momentum or polarization. Our results can be
useful to investigate the spin-orbit interactions of light for complex
evanescent fields. Note that the spin of the incident light can control the
rotation direction of the canonical momentum.",1703.00205v2
2022-12-27,Electric-field-driven spin resonance by on-surface exchange coupling to a single-atom magnet,"Coherent control of individual atomic and molecular spins on surfaces has
recently been demonstrated by using electron spin resonance (ESR) in a scanning
tunneling microscope (STM). Here we present a combined experimental and
modeling study of the ESR of a single hydrogenated Ti atom that is
exchange-coupled to a Fe adatom located in 0.6-0.8 nm away. Continuous wave and
pulsed ESR of the Ti spin showed a Rabi rate with two contributions, one from
the tip and the other from the Fe, whose spin interactions with Ti were
modulated by the radio-frequency electric field. The Fe contribution is
comparable to the tip, as revealed from its dominance when the tip was
retracted, and tunable using a vector magnetic field. Our new ESR scheme allows
on-surface individual spins to be addressed and coherently controlled without
the need for magnetic interaction with a tip. This study establishes a feasible
implementation of spin-based multi-qubit systems on surfaces.",2212.13380v2
2018-10-16,Spin-torque oscillation in a magnetic insulator probed by a single-spin sensor,"Coherent, self-sustained oscillation of magnetization in spin-torque
oscillators (STOs) is a promising source for on-chip, nanoscale generation of
microwave magnetic fields. Such fields could be used for local excitation of
spin-wave resonances, control of spin qubits, and studies of paramagnetic
resonance. However, local characterization of fields emitted by an STO has
remained an outstanding challenge. Here, we use the spin of a single
nitrogen-vacancy (NV) defect in diamond to probe the magnetic fields generated
by an STO in a microbar of ferromagnetic insulator yttrium-iron-garnet (YIG).
The combined spectral resolution and sensitivity of the NV sensor allows us to
resolve multiple spin-wave modes and characterize their damping. When damping
is decreased sufficiently via spin injection, the modes auto-oscillate, as
indicated by a strongly reduced linewidth, a diverging magnetic power spectral
density, and synchronization of the STO frequency to an external microwave
source. These results open the way for quantitative, nanoscale mapping of the
microwave signals generated by STOs, as well as harnessing STOs as local probes
of mesoscopic spin systems.",1810.07306v1
2011-01-31,"Stripes, spin resonance and $d_{x^2-y^2}-$pairing symmetry in FeSe-based layered superconductors","We calculate RPA-BCS based spin resonance spectra of newly discovered
iron-selenide superconductor using two orbitals tight-binding (TB) model. The
slightly squarish electron pocket Fermi surfaces (FSs) at
$(\pi,0)/(0,\pi)-$momenta produce leading interpocket nesting instability at
incommensurate vector $q\sim(\pi,0.5\pi)$ in the normal state static
susceptibility, pinning a strong stripe-like spin-density wave (SDW) or
antiferromagnetic (AFM) order at some critical value of $U$. The same nesting
also induces $d_{x^2-y^2}-$pairing. The superconducting (SC) gap is nodeless
and isotropic on the FSs as they are concentric to the four-fold symmetry point
of the $d-$wave gap maxima, in agreement with various measurements. This
induces an slightly incommensurate spin resonance with `hour-glass'-like
dispersion feature, in close agreement with neutron data of chalcogenides. We
also calculate $T$ pendence of the SC gap solving BCS gap equations and find
that the spin resonance follows the same $T$ evolution of $\Delta(T)$ both in
energy and intensity, suggesting that an itinerant weak or intermediate pair
coupling theory is relevant in this system.",1101.6056v3
2017-08-04,"Identification of spin wave resonances and crystal field transitions in simple chromites RCrO3 (R=Pr, Sm, Er) at ultralow temperatures in the THz spectral region","We report on THz absorption spectroscopy combined with high magnetic fields
of polycrystalline RCrO3 (R= Pr, Sm, Er) aiming understanding spin wave
resonances at their low temperature magnetic phases. Our measurements show that
the temperature, and the implicit anisotropies at which the Cr3+ spin
reorientation at TSR takes place, are determinant on the ferromagnetic-like
(FM) and the antiferromagnetic-like (AFM) spin modes being optically active. It
is found that they are dependent on Rare Earth 4f moment and ion size. We also
studied temperature and field dependence of crystal field levels in the same
spectroscopic region. Pr3+ non-Kramers emerges at 100 K and Zeeman splits. An
observed absence of spin wave resonances in PrCrO3 is attributed to Pr3+
remaining paramagnetic. In SmCrO3 near cancelation of the spin and orbital
moments is proposed as the possible reason for not detecting Sm3+ ground state
transitions. Here, the FM and AFM resonant modes harden when the temperature
decreases and split linearly on applied fields at 5 K and below. In ErCrO3 the
Er3+ Kramers doublet becomes active at about the TSR onset. Each line further
experiences Zeeman splitting under magnetic fields while an spin reversal
induced by a 2.5 T field, back to the Gamma4 (Fz) from the Gamma1 phase at 2 K,
produces a secondary splitting. The 5 K AFM and FM excitations in ErCrO3 have a
concerted frequency-intensity temperature dependence and a shoulder pointing to
the Er3+ smaller ion size also disrupting the two magnetic sublattice
approximation . Both resonances reduce to one when the temperature is lowered
to 2 K in the Gamma1 representation.",1708.01497v1
2014-03-27,Distinguishing black-hole spin-orbit resonances by their gravitational-wave signatures,"If binary black holes form following the successive core collapses of
sufficiently massive binary stars, precessional dynamics may align their spins
$\mathbf S_1$ and $\mathbf S_2$ and the orbital angular momentum $\mathbf L$
into a plane in which they jointly precess about the total angular momentum
$\mathbf J$. These spin orientations are known as spin-orbit resonances since
$\mathbf S_1$, $\mathbf S_2$, and $\mathbf L$ all precess at the same frequency
to maintain their planar configuration. Two families of such spin-orbit
resonances exist, alike in dignity but differentiated by whether the components
of the two spins in the orbital plane are either aligned or antialigned. The
fraction of binary black holes in each family is determined by the stellar
evolution of their progenitors, so if gravitational-wave detectors could
measure this fraction they could provide important insights into astrophysical
formation scenarios for binary black holes. In this paper, we show that even
under the conservative assumption that binary black holes are observed along
the direction of $\mathbf J$ (where precession-induced modulations to the
gravitational waveforms are minimized), the waveforms of many members of each
resonant family can be distinguished from all members of the opposing family in
events with signal-to-noise ratios $\rho \simeq 10$, typical of those expected
for the first detections with Advanced LIGO/Virgo. We hope that our preliminary
findings inspire a greater appreciation of the capability of gravitational-wave
detectors to constrain stellar astrophysics and stimulate further studies of
the distinguishability of spin-orbit resonant families in more expanded regions
of binary black-hole parameter space.",1403.7147v2
2002-03-01,Baryon resonances and strong QCD,"Light-baryon resonances (with u,d, and s quarks in the SU(3) classification)
fall on Regge trajectories. When their squared masses are plotted against the
intrinsic orbital angular momenta {\rm L}, $\Delta^*$'s with even and odd
parity can be described by the same Regge trajectory. For a given {\rm L},
nucleon resonances with spin {\rm S}=3/2 are approximately degenerate in mass
with $\Delta$ resonances. To which total angular momentum {\rm L} and {\rm S}
couple has no significant impact on the baryon mass. Nucleons with spin 1/2 are
shifted in mass; the shift is - in units of squared masses - proportional to
the component in the wave function which is antisymmetric in spin and flavor.
Based on these observations, a new baryon mass formula is proposed which
reproduces nearly all known baryon masses. It is shown that the masses are
compatible with a quark-diquark picture while the richness of the
experimentally known states require three particles to participate in the
dynamics. This conflict is resolved by proposing that quarks polarize the QCD
condensates and are surrounded by a polarization cloud shielding the color. A
new interpretation of constituent quarks as colored quark clusters emerges;
their interaction is responsible for the mass spectrum. Fast flavor exchange
between the colored quark clusters exhausts the dynamical richness of the
three-particle dynamics. The colored-quark-cluster model provides a mechanism
in which the linear confinement potential can be traced to the increase of the
volume in which the condensates are polarized. The quark-spin magnetic moment
induces currents in the polarized condensates which absorb the quark-spin
angular momentum: the proton spin is not carried by quark spins. The model
provides a new picture of hybrids and glueballs.",0203002v1
1997-08-30,Nuclear magnetic resonance spectroscopy: An experimentally accessible paradigm for quantum computing,"We present experimental results which demonstrate that nuclear magnetic
resonance spectroscopy is capable of efficiently emulating many of the
capabilities of quantum computers, including unitary evolution and coherent
superpositions, but without attendant wave-function collapse. Specifically, we
have: (1) Implemented the quantum XOR gate in two different ways, one using
Pound-Overhauser double resonance, and the other using a spin-coherence double
resonance pulse sequence; (2) Demonstrated that the square root of the
Pound-Overhauser XOR corresponds to a conditional rotation, thus obtaining a
universal set of gates; (3) Devised a spin-coherence implementation of the
Toffoli gate, and confirmed that it transforms the equilibrium state of a
four-spin system as expected; (4) Used standard gradient-pulse techniques in
NMR to equalize all but one of the populations in a two-spin system, so
obtaining the pseudo-pure state that corresponds to |00>; (5) Validated that
one can identify which basic pseudo-pure state is present by transforming it
into one-spin superpositions, whose associated spectra jointly characterize the
state; (6) Applied the spin-coherence XOR gate to a one-spin superposition to
create an entangled state, and confirmed its existence by detecting the
associated double-quantum coherence via gradient-echo methods.",9709001v2
2012-07-27,Spin transition rates in nanowire superlattices: Rashba spin-orbit coupling effects,"We investigate the influence of Rashba spin-orbit coupling in a parabolic
nanowire modulated by longitudinal periodic potential. The modulation potential
can be obtained from realistically grown supperlattices (SLs). Our study shows
that the Rashba spin-orbit interaction induces the level crossing point in the
parabolic nanowire SLs. We estimate large anticrossing width (approximately 117
$\mu eV$) between singlet-triplet states. We study the phonon and
electromagnetic field mediated spin transition rates in the parabolic nanowire
SLs. We report that the phonon mediated spin transition rate is several order
of magnitude larger than the electromagnetic field mediated spin transition
rate. Based on the Feynman disentangling technique, we find the exact spin
transition probability. For the case wave vector $k=0$, we report that the
transition probability can be tuned in the form of resonance at fixed time
interval. For the general case ($k\neq 0$), we solve the Riccati equation and
find that the arbitrary values of $k$ induces the damping in the transition
probability. At large value of Rashba spin-orbit coupling coefficients for
($k\neq 0$), spin transition probability freezes.",1207.6580v2
2019-06-01,Coherent ac spin current transmission across an antiferromagnetic CoO insulator,"The recent discovery of spin-current transmission through antiferromagnetic
(AFM) insulating materials opens up unprecedented opportunities for fundamental
physics and spintronics applications. The great mystery currently surrounding
this topic is: how could THz AFM magnons mediate a GHz spin current? This
mis-match of frequencies becomes particularly critical for the case of coherent
ac spin-current, raising the fundamental question of whether a GHz ac
spin-current can ever keep its coherence inside an AFM insulator and so drive
the spin precession of another FM layer coherently? Utilizing element- and
time-resolved x-ray pump-probe measurements on Py/Ag/CoO/Ag/Fe75Co25/MgO(001)
heterostructures, we demonstrate that a coherent GHz ac spin current pumped by
the permalloy (Py) ferromagnetic resonance (FMR) can transmit coherently across
an antiferromagnetic CoO insulating layer to drive a coherent spin precession
of the FM Fe75Co25 layer. Further measurement results favor thermal magnons
rather than evanescent spin waves as the mediator of the coherent ac spin
current in CoO.",1906.00155v1
2022-03-08,Spin excitations of a proximate Kitaev quantum spin liquid realized in Cu$_2$IrO$_3$,"Magnetic moments arranged at the corners of a honeycomb lattice are predicted
to form a novel state of matter, Kitaev quantum spin liquid, under the
influence of frustration effects between bond-dependent Ising interactions.
Some layered honeycomb iridates and related materials, such as
Na$_{2}$IrO$_{3}$ and $\alpha$-RuCl$_{3}$, are proximate to Kitaev quantum spin
liquid, but bosonic spin-wave excitations associated with undesirable
antiferromagnetic long-range order mask the inherent properties of Kitaev
Hamiltonian. Here, we use $^{63}$Cu nuclear quadrupole resonance to uncover the
low energy spin excitations in the nearly ideal honeycomb lattice of effective
spin $S = 1/2$ at the Ir$^{4+}$ sites in Cu$_{2}$IrO$_{3}$. We demonstrate
that, unlike Na$_{2}$IrO$_{3}$, Ir spin fluctuations exhibit no evidence for
critical slowing down toward magnetic long range order in zero external
magnetic field. Moreover, the low energy spin excitation spectrum is dominated
by a mode that has a large excitation gap comparable to the Ising interactions,
a signature expected for Majorana fermions of Kitaev quantum spin liquid.",2203.04261v1
2016-09-19,Geometrical complexity of the antidots unit cell effect on the spin wave excitations spectra,"We have investigated theoretically (with micromagnetic simulations and plane
wave method) and experimentally (with ferromagnetic resonance and Brillouin
light scattering) three types of antidot lattices (ADLs) based on permalloy
thin films with increased complexity of the unit cell: simple square,
bi-component square and wave-like ADL. We have found that placing a small
additional antidot in the center of the unit cell of the square ADL modify
significantly the spin wave spectrum and its dependence on the orientation of
the in-plane magnetic field. We also check the further changes of spin wave
spectrum resulting from the introduction of air-gaps connecting small and large
antidots. In particular, the presence of small antidots change the dependence
of the frequency of the fundamental mode on the angle of the in-plane applied
magnetic field. The air-gaps strongly discriminates the propagation of spin
waves in two principal direction of ADL lattice, orthogonal to each other. In
spite of these spectral changes, the spatial distribution of the spin wave
amplitude generally preserves some similarities for all three structures. We
also highlighted out the role of defects in the ADL in the observed spectra.
The obtained results can be interesting for the magnonics applications of the
magnonic crystals.",1609.05663v1
2013-02-03,Superconducting Resonance and paring symmetry in electron-doped cuprates,"The magnetic excitations in the superconducting electron-doped cuprates are
studied in the framework of spin-density-wave description. The superconducting
resonance is a natural product of the superconductivity due to the opening of
d-wave gap. Its resonance energy exhibits well linear scaling with
superconducting gap as $E_{res}/2\Delta\sim 0.6$, quantitatively consisting
with the experimental discovery. This ratio is insensitive to the selected
parameters, manifesting its universality. Another lower-energy peak below
resonance energy is predicted when the hole pocket emerges due to suppression
of spin-density wave. We further verify that the ratio of linear scales is
intimately related to the pairing symmetry. Distinct ratio can be found with
respective pairing symmetry. In comparison with the inelastic neutron
scattering data, the monotonic d-wave superconductivity is the most likely
candidate in the electron-doped cuprates. Furthermore, we proposed a new method
to check the pairing symmetry by the inelastic neutron scattering measurements.",1302.0453v1
2020-12-17,Energy-efficient spin injector into semiconductors driven by elastic waves,"Generation of spin imbalance in nonmagnetic semiconductors is crucial for the
functioning of many spintronic devices. An attractive design of spin injectors
into semiconductors is based on a spin pumping from a precessing ferromagnet,
typically excited by a microwave magnetic field leading to a high power
consumption of the device. Here we describe theoretically a spin injector with
greatly reduced energy losses, in which the magnetic dynamics is excited by an
elastic wave injected into a ferromagnet-semiconductor heterostructure. To
demonstrate the efficient functioning of such an injector, we perform
micromagnetoelastic simulations of the coupled elastic and magnetic dynamics in
Ni films and Ni/GaAs bilayers. For thick Ni films, it is shown that a
monochromatic acoustic wave generates a spin wave with the same frequency and
wavelength, which propagates over distances of several micrometers at the
excitation frequencies close to the frequency of ferromagnetic resonance. The
simulations of Ni/GaAs bilayers with Ni thicknesses comparable to the
wavelength of the injected acoustic wave demonstrate the development of a
steady-state magnetization precession at the Ni/GaAs interface. The amplitude
of such a precession has a maximum at Ni thickness amounting to three quarters
of the wavelength of the elastic wave, which is explained by an analytical
model. Using simulation data obtained for the magnetization precession at the
Ni/GaAs interface, we evaluate the spin current pumped into GaAs and calculate
the spin accumulation in it by solving the spin diffusion equation. Then the
electrical signals resulting from the spin flow and the inverse spin Hall
effect are determined via the numerical solution of the Laplace's equation. It
is shown that amplitudes of these ac signals are large enough for experimental
measurement, which indicates an efficient acoustically driven spin pumping into
GaAs.",2012.09531v1
2010-07-05,Rabi Waves in Carbon Nanotubes - Experiment,"Rabi waves have been experimentally registered for the first time by Raman
scattering studies of zigzag nanotubes, produced by high energy ion beam
modification of natural diamond single crystals. Antiferroelectric spin wave
resonance has been detected for the first time in Raman spectroscopy practice
in given samples. Substantial qualitative and quantitative changes in Raman
spectra in dependence on propagation direction of laser excitation wave have
been found.",1007.0654v2
2015-08-21,Radiative damping in wave guide based FMR measured via analysis of perpendicular standing spin waves in sputtered Permalloy films,"The damping $\alpha$ of the spinwave resonances in 75 nm, 120 nm, and 200nm
-thick Permalloy films is measured via vector-network-analyzer
ferromagnetic-resonance (VNA-FMR) in the out-of-plane geometry. Inductive
coupling between the sample and the waveguide leads to an additional radiative
damping term. The radiative contribution to the over-all damping is determined
by measuring perpendicular standing spin waves (PSSWs) in the Permalloy films,
and the results are compared to a simple analytical model. The damping of the
PSSWs can be fully explained by three contributions to the damping: The
intrinsic damping, the eddy-current damping, and the radiative damping. No
other contributions were observed. Furthermore, a method to determine the
radiative damping in FMR measurements with a single resonance is suggested.",1508.05265v1
2016-08-11,Chiral magnetic excitations in FeGe films,"Although chiral magnetic materials have emerged as a potential ingredient in
future spintronic memory devices, there are few comprehensive studies of
magnetic properties in scalably-grown thin films. We present growth, systematic
physical and magnetic characterization, and microwave absorption spectroscopy
of B20 FeGe thin films. We also perform micromagnetic simulations and
analytical theory to understand the dynamical magnetic behavior of this
material. We find magnetic resonance features in both the helical and
field-polarized magnetic states that are well explained by micromagnetic
simulations and analytical calculations. In particular, we show the resonant
enhancement of spin waves along the FeGe film thickness that has a wave vector
matching the helical vector. Using our analytic model, we also describe the
resonance frequency of a helical magnetic state, which depends solely on its
untwisting field. Our results pave the way for understanding and manipulating
high frequency spin waves in thin-film chiral-magnet FeGe near room
temperature.",1608.03582v1
2016-11-02,Determining the dominant partial wave contributions from angular distributions of single- and double-polarization observables in pseudoscalar meson photoproduction,"This work presents a simple method to determine the significant partial wave
contributions to experimentally determined observables in pseudoscalar meson
photoproduction. First, fits to angular distributions are presented and the
maximum orbital angular momentum $\text{L}_{\mathrm{max}}$ needed to achieve a
good fit is determined. Then, recent polarization measurements for $\gamma p
\rightarrow \pi^{0} p$ from ELSA, GRAAL, JLab and MAMI are investigated
according to the proposed method. This method allows us to project high-spin
partial wave contributions to any observable as long as the measurement has the
necessary statistical accuracy. We show, that high precision and large angular
coverage in the polarization data are needed in order to be sensitive to
high-spin resonance-states and thereby also for the finding of small resonance
contributions. This task can be achieved via interference of these resonances
with the well-known states. For the channel $\gamma p \rightarrow \pi^{0} p$,
those are the $N(1680)\frac{5}{2}^{+}$ and $\Delta(1950)\frac{7}{2}^{+}$,
contributing to the $F$-waves.",1611.01031v2
2016-07-19,Spin resonance in the superconducting state of Li$_{1-x}$Fe$_{x}$ODFe$_{1-y}$Se observed by neutron spectroscopy,"We have performed inelastic neutron scattering measurements on a powder
sample of the superconductor lithium iron selenide hydroxide
Li$_{1-x}$Fe$_{x}$ODFe$_{1-y}$Se ($x \simeq 0.16, y \simeq 0.02$, $T_{\rm c} =
41$\,K). The spectrum shows an enhanced intensity below $T_{\rm c}$ over an
energy range $0.64\times2\Delta < E < 2\Delta$, where $\Delta$ is the
superconducting gap, with maxima at the wave vectors $Q_1 \simeq
1.46$\,\AA$^{-1}$ and $Q_2 \simeq 1.97$\,\AA$^{-1}$. The behavior of this
feature is consistent with the spin resonance mode found in other
unconventional superconductors, and strongly resembles the spin resonance
observed in the spectrum of the molecular-intercalated iron selenide,
Li$_{0.6}$(ND$_{2}$)$_{0.2}$(ND$_{3}$)$_{0.8}$Fe$_{2}$Se$_{2}$. The signal can
be described with a characteristic two-dimensional wave vector $(\pi, 0.67\pi)$
in the Brillouin zone of the iron square lattice, consistent with the nesting
vector between electron Fermi sheets.",1607.05588v2
2012-08-28,Modulation frequency dependence of continuous-wave optically/electrically detected magnetic resonance,"Continuous wave optically and electrically detected magnetic resonance
spectroscopy (cwODMR/cwEDMR) allow the investigation of paramagnetic states
involved in spin-dependent transitions, like recombination and transport.
Although experimentally similar to conventional electron spin resonance (ESR),
there exist limitations when applying models originally developed for ESR to
observables (luminescence and electric current) of cwODMR and cwEDMR. Here we
present closed-form solutions for the modulation frequency dependence of cwODMR
and cwEDMR based on an intermediate pair recombination model and discuss
ambiguities which arise when attempting to distinguish the dominant
spin-dependent processes underlying experimental data. These include: 1) a
large number of quantitatively different models cannot be differentiated, 2)
signs of signals are determined not only by recombination, but also by other
processes like dissociation, intersystem-crossing, pair generation, and even
experimental parameter such as, modulation frequency, microwave power, and
temperature, 3) radiative and non-radiative recombination cannot be
distinguished due to the observed signs of cwODMR and cwEDMR experiments.",1208.5573v1
2013-07-09,Spin-Density-Wave-Type Ordering of LaCoGe Revealed by ^{59}Co- and ^{139}La-Nuclear Magnetic Resonance Measurements,"The low-temperature magnetic properties of LaCoGe with the tetragonal
CeFeSi-type structure were investigated by ^{59}Co- and ^{139}La-nuclear
magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) measurements.
The nuclear spin-lattice relaxation rate divided by the temperature, 1/(T_1 T),
gradually increases with decreasing temperature and shows a kink at
approximately 18 K, below which an inhomogeneous internal field appears at the
Co nuclear site. These results indicate that antiferromagnetic ordering occurs
below T_N ~ 18 K. However, an internal field was not observed at the La nuclear
site below T_N. Taking all NMR results into account, we conclude that
spin-density-wave (SDW)-type ordering occurs, where magnetic correlations are
of the checkerboard type in the ab-plane and have a long periodicity along the
c-axis with inhomogeneous ordered moments pointing to the c-axis.",1307.2412v1
2023-01-03,Numerical study of magneto-optical binding between two dipolar particles under illumination by two counter-propagating waves,"The formation of a stable magneto plasmonic dimer with THz resonances is
theoretically studied for the principal directions of the system. Unlike a
recent report, our work provides a complete description of the full photonic
coupling for arbitrary magnetic fields as, for instance, unbalanced particle
spins. As an illustration, we consider two small, n-doped InSb nanoparticles
under illumination by two counter-propagating plane waves. Remarkably, when an
external magnetic field exists, the symmetry in the system is broken, and a
resonant radiation pressure for the dimer appears. Similarly, tunable
inter-particle forces and spins are exerted on the non-reciprocal dimer. The
system is also characterized when the magnetic field is absent. Moreover, we
show how the mechanical observables truly characterize the dimer since their
resonance dependency contains detailed information about the system. Unlike
far-field observables like absorption, mechanical magnitudes depend on the
system's near-field. In addition, the nature of the particle spins is
originally explained by the energy flow's behavior around the dimer. This work
constitutes a generalization of any previous approach to optical binding
between small nanoparticles. It paves the way for fully controlling optical
matter and nano factory designs based on surface plasmon polaritons.",2301.01213v1
2023-07-09,Dzyaloshinskii-Moriya torque-driven resonance in antiferromagnetic α-Fe2O3,"We examine the high-frequency optical mode of {\alpha}-Fe2O3 and report that
Dzyaloshinskii-Moriya (DM) interaction generates a new type of torque on the
magnetic resonance. Using a continuous-wave terahertz interferometer, we
measure the optical mode spectra, where the asymmetric absorption with a large
amplitude and broad linewidth is observed near the magnetic transition point,
Morin temperature (TM ~ 254.3 K). Based on the spin wave model, the spectral
anomaly is attributed to the DM interaction-induced torque, enabling to extract
the strength of DM interaction field of 4 T. Our work opens a new avenue to
characterize the spin resonance behaviors at an antiferromagnetic singular
point for next-generation and high-frequency spin-based information
technologies.",2307.04135v1
2024-03-27,Extreme Terahertz Magnon Multiplication Induced by Resonant Magnetic Pulse Pairs,"Nonlinear interactions of spin-waves and their quanta, magnons, have emerged
as prominent candidates for interference-based technology, ranging from quantum
transduction to antiferromagnetic spintronics. Yet magnon multiplication in the
terahertz (THz) spectral region represents a major challenge. Intense, resonant
magnetic fields from THz pulse-pairs with controllable phases and amplitudes
enable high order THz magnon multiplication, distinct from non-resonant
nonlinearities such as the high harmonic generation by below-band gap electric
fields. Here, we demonstrate exceptionally high-order THz nonlinear magnonics.
It manifests as 7$^\text{th}$-order spin-wave-mixing and 6$^\text{th}$ harmonic
magnon generation in an antiferromagnetic orthoferrite. We use THz
multi-dimensional coherent spectroscopy to achieve high-sensitivity detection
of nonlinear magnon interactions up to six-magnon quanta in strongly-driven
many-magnon correlated states. The high-order magnon multiplication, supported
by classical and quantum spin simulations, elucidates the significance of
four-fold magnetic anisotropy and Dzyaloshinskii-Moriya symmetry breaking.
Moreover, our results shed light on the potential quantum fluctuation
properties inherent in nonlinear magnons.",2403.18168v1
2014-03-01,Measuring the spin of black holes in binary systems using gravitational waves,"Compact binary coalescences are the most promising sources of gravitational
waves (GWs) for ground based detectors. Binary systems containing one or two
spinning black holes are particularly interesting due to spin-orbit (and
eventual spin-spin) interactions, and the opportunity of measuring spins
directly through GW observations. In this letter we analyze simulated signals
emitted by spinning binaries with several values of masses, spins, orientation,
and signal-to-noise ratio. We find that spin magnitudes and tilt angles can be
estimated to accuracy of a few percent for neutron star--black hole systems and
$\sim$ 5-30% for black hole binaries. In contrast, the difference in the
azimuth angles of the spins, which may be used to check if spins are locked
into resonant configurations, cannot be constrained. We observe that the best
performances are obtained when the line of sight is perpendicular to the
system's total angular momentum, and that a sudden change of behavior occurs
when a system is observed from angles such that the plane of the orbit can be
seen both from above and below during the time the signal is in band. This
study suggests that the measurement of black hole spin by means of GWs can be
as precise as what can be obtained from X-ray binaries.",1403.0129v2
2008-10-27,"Spin polarized two-dimensional electron gas embedded in semimagnetic quantum well : ground state, spin responses, spin excitations, Raman spectrum","We present theoretical aspects of spin polarized two dimensional electron gas
(SP2DEG) which can be achieved in doped semimagnetic quantum wells. This
original model system has been recently studied by magneto Raman scattering
experiments has given a new access to spin resolved excitations and spectrum of
the SP2DEG. Starting from the Diluted Magnetic Semiconductor (DMS) Hamiltonian
in presence of the Coulomb interaction between conduction electrons, we define
the conditions to reach such a SP2DEG. The equilibrium state is studied at low
temperature; in particular a theory for the degree of spin polarization is
derived. Dynamical spin susceptibilities are further calculated in the
framework of a spin density functional formalism already developed in the past.
We then derive spin conserving and spin flip excitations dispersions using a
recent determination of the SP2DEG correlation energy corrected from the
thickness of the well. The SP2DEG presents two key features: the spin flip
wave, which existence is a direct consequence of the Coulomb interaction
between the spin polarized electrons, with a dispersion and energy range
typical to the SP2DEG obtained in DMS, the spin density fluctuations exhibiting
a specific collective behaviour when the spin polarization is increased. The
dissipation spectrum through these excitations is studied in detail. Particular
attention is given to the spectrum determined by resonant Raman scattering. We
show, indeed, that the latter gives unique access to the spin-fluctuations
spectrum of the SP2DEG.",0810.4872v1
2018-01-13,Tailoring multilayer quantum wells for spin devices,"The electron spin dynamics in multilayer GaAs/AlGaAs quantum wells,
containing high-mobility dense two-dimensional electron gases, have been
studied using time-resolved Kerr rotation and resonant spin amplification
techniques. The electron spin dynamics was regulated through the wave function
engineering and quantum confinement in multilayer quantum wells. We observed
the spin coherence with a remarkably long dephasing time T2* > 13 ns for the
structure doped beyond metal-insulator transition. Dyakonov-Perel spin
relaxation mechanism, as well as the inhomogeneity of electron g-factor, was
suggested as the major limiting factors for the spin coherence time. In the
metallic regime, we found that the electron-electron collisions become dominant
over microscopic scattering on the electron spin relaxation with the
Dyakonov-Perel mechanism. Furthermore, the data analysis indicated that in our
structure, due to the spin relaxation anisotropy, Dyakonov-Perel spin
relaxation mechanism is efficient for the spins oriented in-plane and
suppressed along the quantum well growth direction resulting in the enhancement
of T2*. Our findings, namely, long-lived spin coherence persisting up to about
room temperature, spin polarization decay time with and without a magnetic
field, the spin-orbit field, single electron relaxation time, transport
scattering time, and the electron-electron Coulomb scattering time highlight
the attractiveness of n-doped multilayer systems for spin devices.",1801.04426v1
2022-07-13,Jahn-Teller states mixed by spin-orbit coupling in an electromagnetic field,"Spin-orbit coupling plays a pivotal role in condensed matter physics. For
instance, spin-orbit interactions affect the magnetization and transport
dynamics in solids, while spins and momenta are locked in topological matter.
Alternatively, spin-orbit entanglement may play an important role in exotic
phenomena, like quantum spin liquids in 4d and 5d systems. An interesting
question is how electronic states mixed by spin orbit coupling interact with
electromagnetic fields, which may hold potential to tune their properties and
reveal interesting physics. Motivated by our recent discovery of large
gyrotropic signals in some Jahn-Teller manganites, here we explore the
interaction of light with spin-mixed states in a d4 transition metal. We show
that spin-orbit mixing enables electronic transitions that are sensitive to
circularly polarized light, giving rise to a gyrotropic response that increases
with spin-orbit coupling. Interestingly, photoexcited transitions that involve
spin reversal are behind such gyrotropic resonances. Additionally, we find that
the interaction with the electromagnetic field depends strongly on the relative
orientation of the propagation of light with respect to Jahn-Teller distortions
and spin quantization. We suggest that such interactions offer the opportunity
to use electromagnetic waves at optical wavelengths to entangle orbital and
spin degrees of freedom. Our approach, which includes a group-theoretical
treatment of spin-orbit coupling, has wide applicability and provides a
versatile tool to explore the interaction of electromagnetic fields with
electronic states in transition metals with arbitrary spin-orbit coupling
strength and pointgroup symmetries.",2207.06501v1
2018-07-09,Cavity-induced emergent topological spin textures in a Bose Einstein condensate,"The coupled nonlinear dynamics of ultracold quantum matter and
electromagnetic field modes in an optical resonator exhibits a wealth of
intriguing collective phenomena. Here we study a $\Lambda$-type,
three-component Bose-Einstein condensate coupled to four dynamical running-wave
modes of a ring cavity, where only two of the modes are externally pumped.
However, the unpumped modes play a crucial role in the dynamics of the system
due to coherent back-scattering of photons. On a mean- field level we identify
three fundamentally different steady-state phases with distinct characteristics
in the density and spatial spin textures: a combined density and spin wave, a
continuous spin spiral with a homogeneous density, and a spin spiral with a
modulated density. The spin-spiral states, which are topological, are
intimately related to cavity-induced spin-orbit coupling emerging beyond a
critical pump power. The topologically trivial density-wave--spin-wave state
has the characteristics of a supersolid with two broken continuous symmetries.
The transitions between different phases are either simultaneously topological
and first order, or second order. The proposed setup allows the simulation of
intriguing many-body quantum phenomena by solely tuning the pump amplitudes and
frequencies, with the cavity output fields serving as a built-in nondestructive
observation tool.",1807.03316v1
2006-04-12,Spin diffusion and the anisotropic spin-1/2 Heisenberg chain,"Measurements of the spin-lattice relaxation rate 1/T_1 by nuclear magnetic
resonance for the one-dimensional Heisenberg antiferromagnet Sr_2CuO_3 have
provided evidence for a diffusion-like contribution at finite temperature and
small wave-vector. By analyzing real-time data for the auto- and
nearest-neighbor spin-spin correlation functions obtained by the density-matrix
renormalization group I show that such a contribution indeed exists for
temperatures T>J, where J is the coupling constant, but that it becomes
exponentially suppressed for T << J. I present evidence that the
frequency-dependence of 1/T_1 in the Heisenberg case is smoothly connected to
that in the free fermion case where the exponential suppression of the
diffusion-like contribution is easily understood.",0604327v1
2010-11-19,"Anisotropic spin fluctuations and superconductivity in ""115'' heavy fermion compounds: 59Co NMR study in PuCoGa5","We report results of $^{59}$Co nuclear magnetic resonance measurements on a
single crystal of superconducting PuCoGa5 in its normal state. The nuclear
spin-lattice relaxation rates and the Knight shifts as a function of
temperature reveal an anisotropy of spin fluctuations with finite wave vector
q. By comparison with the isostructural members, we conclude that
antiferromagnetic XY-type anisotropy of spin fluctuations plays an important
role in mediating superconductivity in these heavy fermion materials.",1011.4466v1
2017-08-31,Highly efficient optical pumping of spin defects in silicon carbide for stimulated microwave emission,"We investigate the pump efficiency of silicon vacancy-related spins in
silicon carbide. For a crystal inserted into a microwave cavity with a
resonance frequency of 9.4 GHz, the spin population inversion factor of 75 with
the saturation optical pump power of about 350 mW is achieved at room
temperature. At cryogenic temperature, the pump efficiency drastically
increases, owing to an exceptionally long spin-lattice relaxation time
exceeding one minute. Based on the experimental results, we find realistic
conditions under which a silicon carbide maser can operate in continuous-wave
mode and serve as a quantum microwave amplifier.",1709.00052v1
2005-08-09,Many-spin effects in inelastic neutron scattering and electron paramagnetic resonance of molecular nanomagnets,"Many molecular magnetic clusters, such as single-molecule magnets, are
characterized by spin ground states with defined total spin S exhibiting
zero-field-splittings. In this work, the spectroscopic intensities of the
transitions within the ground-state multiplet are analyzed. In particular, the
effects of a mixing with higher-lying spin multiplets, which is produced by
anisotropic interactions and is neglected in the standard single-spin
description, are investigated systematically for the two experimental
techniques of inelastic neutron scattering (INS) and electron paramagnetic
resonance (EPR), with emphasis on the former technique. The spectroscopic
transition intensities are calculated analytically by constructing
corresponding effective spin operators perturbationally up to second order and
consequently using irreducible tensor operator techniques. Three main effects
of spin mixing are observed. Firstly, a pronounced dependence of the INS
intensities on the momentum transfer Q, with a typical oscillatory behavior,
emerges in first order, signaling the many-spin nature of the wave functions in
exchange-coupled clusters. Secondly, as compared to the results of a
first-order calculation, the intensities of the transitions within the spin
multiplet are affected differently by spin mixing. This allows one, thirdly, to
differentiate the higher-order contributions to the cluster magnetic anisotropy
which come from the single-ion ligand-field terms and spin mixing,
respectively. The analytical results are illustrated by means of the three
examples of an antiferromagnetic heteronuclear dimer, the Mn-[3 x 3] grid
molecule, and the single-molecule magnet Mn12.",0508225v1
2008-02-09,Spin dynamics near the critical doping in weakly-superconducting underdoped YBa2Cu3O6.35 (Tc=18K),"Using neutron scattering we have determined the magnetic structure and
fluctuations in the YBa2Cu3O6.35 superconductor (Tc=18 K). The long-range
ordered collinear spins of the insulating antiferromagnet are replaced by a
commensurate central mode arising from slow, isotropically polarized,
short-range spin correlations. The inelastic spectrum up to 30 meV is broad in
wave vector and commensurate. In contrast to the the resonance peak of higher
Tc superconductors, the spins exhibit a single overdamped spectrum whose rate
of relaxation decreases on cooling and saturates at 5 meV below 50 K. As the
relaxation rate saturates the quasi-static spin correlations grow and become
resolution limited in energy. The spin susceptibility at high temperatures
illustrates that the dominant energy scale is set by the temperature. At low
temperatures, the scale length is geometric and not linked by velocity to
dynamic widths. There is no observable suppression of the spin fluctuations or
central mode upon the onset of superconductivity. The spins respond not to
coherent charge pairs but to hole doping allowing coexistence of glassy short
range spin order with superconductivity. Since the physics of the weakly
superconducting system YBCO6.35 must connect continuously with that in more
strongly superconducting YBCO6.5, we find that neither incommensurate
stripe-like spin modulations nor a well-defined neutron spin resonance are
essential for the onset with doping of pairing in a high temperature cuprate
superconductor.",0802.1252v1
2023-09-22,Laser-induced real-space topology control of spin wave resonances,"Femtosecond laser excitation of materials that exhibit magnetic spin textures
promises advanced magnetic control via the generation of ultrafast and
non-equilibrium spin dynamics. We explore such possibilities in ferrimagnetic
[Fe(0.35 nm)/Gd(0.40 nm)]$_{160}$ multilayers, which host a rich diversity of
magnetic textures from stripe domains at low magnetic fields, a dense
bubble/skyrmion lattice at intermediate fields, and a single domain state for
high magnetic fields. Using femtosecond magneto-optics, we observe distinct
coherent spin wave dynamics in response to a weak laser excitation allowing us
to unambiguously identify the different magnetic spin textures. Moreover,
employing strong laser excitation we show that we achieve versatile control of
the coherent spin dynamics via non-equilibrium and ultrafast transformation of
magnetic spin textures by both creating and annihilating bubbles/skyrmions. We
corroborate our findings by micromagnetic simulations and by Lorentz
transmission electron microscopy before and after laser exposure.",2309.12956v1
2000-08-18,Millimeter-Wave Spectroscopy of the Organic spin-Peierls System b'-(ET)2SF5CF2SO3,"The first purely organic BEDT-TTF spin-Peierls system, b'-(ET)2SF5CF2SO3, has
been confirmed using a high-frequency electron spin resonance (EPR) cavity
perturbation technique. The material exhibits the characteristics of a
quasi-one-dimensional (1D) Heisenberg antiferromagnetic spin system above 30 K,
but undergoes a second-order transition, at TSP = 33 K, to a singlet ground
state, due to a progressive spin-lattice dimerization. The spin-Peierls state
is evidenced by a sharp drop in the spin susceptibility below 24 K for the
magnetic field parallel to each of the three principle axes (i.e. H7a, H7b, and
H7c). The 1D chain axis has been identified as the crystallographic b axis from
the g value analysis. The singlet-triplet gap, Ds(0) = 114 (+-21)K, was
determined using a modified BCS theory. Also, we describe in some detail the
millimeter-wave vector network analyzer (MVNA) for researchers who have
interest in precision EPR measurements at higher magnetic fields and
frequencies.",0008281v1
2011-10-31,Spin excitations and mechanisms of superconductivity in cuprates,"A microscopic theory of spin excitations in strongly-correlated electronic
systems within the t-J model is discussed. An exact representation for the
dynamic spin susceptibility is derived. In the normal state, the excitation
spectrum reveals a crossover from spin-wave-like excitations at low doping to
overdamped paramagnons above the optimal doping. At low temperatures, the
resonance mode at the antiferromagnetic wave vector Q = \pi(1,1) emerges which
is explained by a strong suppression of the spin excitation damping caused by a
spin gap at Q rather than by opening of a superconducting gap. A major role of
spin excitations in the d-wave superconducting pairing in cuprates is stressed
in discussing mechanisms of high-Tc superconductivity within the Hubbard model
in the limit of strong correlations, while electron-phonon interaction and a
well-screened weak Coulomb interaction are not essential.",1110.6715v1
2012-07-31,Surface Acoustic Wave-Driven Ferromagnetic Resonance in Nickel Thin Films: Theory and Experiment,"We present an extensive experimental and theoretical study of surface
acoustic wave-driven ferromagnetic resonance. In a first modeling approach
based on the Landau-Lifshitz-Gilbert equation, we derive expressions for the
magnetization dynamics upon magnetoelastic driving that are used to calculate
the absorbed microwave power upon magnetic resonance as well as the spin
current density generated by the precessing magnetization in the vicinity of a
ferromagnet/normal metal interface. In a second modeling approach, we deal with
the backaction of the magnetization dynamics on the elastic wave by solving the
elastic wave equation and the Landau-Lifshitz-Gilbert equation
selfconsistently, obtaining analytical solutions for the acoustic wave phase
shift and attenuation. We compare both modeling approaches with the complex
forward transmission of a LiNbO$_3$/Ni surface acoustic wave hybrid device
recorded experimentally as a function of the external magnetic field
orientation and magnitude, rotating the field within three different planes and
employing three different surface acoustic wave frequencies. We find
quantitative agreement of the experimentally observed power absorption and
surface acoustic wave phase shift with our modeling predictions using one set
of parameters for all field configurations and frequencies.",1208.0001v1
2014-10-11,Spin wave free spectrum and magnetic field gradient of nanopatterned planes of ferromagnetic cobalt nanoparticles: key properties for magnetic resonance based quantum computing,"We present a study by ferromagnetic resonance at microwave Q band of two
sheets of cobalt nanoparticles obtained by annealing SiO2 layers implanted with
cobalt ions. This ex- perimental study is performed as a function of the
applied magnetic field orientation, tempera- ture, and dose of implanted cobalt
ions. We demonstrate that each of those magnetic sheet of cobalt nanoparticles
can be well modelled by a nearly two dimensional ferromagnetic sheet hav- ing a
reduced effective saturation magnetization, compared to a regular thin film of
cobalt. The nanoparticles are found superparamagnetic above around 210 K and
ferromagnetic below this blocking temperature. Magnetostatic calculations show
that a strong magnetic field gradient of around 0.1 G/nm could be produced by a
ferromagnetic nanostripe patterned in such magnetic sheet of cobalt
nanoparticles. Such a strong magnetic field gradient combined with electron
para- magnetic resonance may be relevant for implementing an intermediate scale
quantum computer based on arrays of coupled electron spins, as previously
reported (Eur. Phys. J. B (2014) 87, 183). However, this new approach only
works if no additional spin decoherence is introduced by the spin waves
exitations of the ferromagnetic nanostructure. We thus suggest theoretically
some possible magnetic anisotropy engineering of cobalt nanoparticles that
could allow to suppress the spin qubit decoherence induced by the unwanted
collective excitation of their spins.",1410.3005v1
2001-02-08,Parametric Resonance of Neutrino Oscillations in Electromagnetic Wave,"Within the Lorentz invariant formalizm for description of neutrino evolution
in electromagnetic fields and matter we consider neutrino spin oscillations in
the circular polarized electromagnetic wave, the amplitude of which is a
modulated function of time. It is shown for the first time that the parametric
resonance of neutrino oscillations can occur in such a system.",0102099v3
2010-03-22,Calculating the Fine Structure of a Fabry-Perot Resonator using Spheroidal Wave Functions,"A new set of vector solutions to Maxwell's equations based on solutions to
the wave equation in spheroidal coordinates allows laser beams to be described
beyond the paraxial approximation. Using these solutions allows us to calculate
the complete first-order corrections in the short-wavelength limit to
eigenmodes and eigenfrequencies in a Fabry-Perot resonator with perfectly
conducting mirrors. Experimentally relevant effects are predicted. Modes which
are degenerate according to the paraxial approximation are split according to
their total angular momentum. This includes a splitting due to coupling between
orbital angular momentum and spin angular momentum.",1003.4168v1
2020-10-31,Interference traps waves in open system: Bound states in the continuum,"I review the four mechanisms of bound states in the continuum (BICs) in
application to microwave and acoustic cavities open to directional waveguides.
The most simple are the symmetry protected BICs which are localized inside the
cavity because of the orthogonality of the eigenmodes to the propagating modes
of waveguides. However, the most general and interesting is the
Friedrich-Wintgen mechanism when the BICs are result of full destructive
interference of outgoing resonant modes. The third type of the BICs, the
Fabry-Perot BICs, occur in a double resonator system when each resonator can
serve as an ideal mirror. At last, the accidental BICs can be realized in the
open cavities with no symmetry like the open Sinai billiard in which the
eigenmode of the resonator can become orthogonal to the continuum of the
waveguide accidentally by a smooth deformation of the eigenmode. We also review
the one-dimensional systems in which the BICs occur owing to full destructive
interference of two waves separated by spin or polarization or by paths in the
Aharonov-Bohm rings. We widely use the method of effective non-Hermitian
Hamiltonian equivalent to the coupled mode theory which detects bound states in
the continuum (BICs) by finding zero widths resonances.",2011.01221v1
2020-01-30,Feshbach spectroscopy of an ultracold $^{41}$K-$^6$Li mixture and $^{41}$K atoms,"We have observed 69 $^{41}$K-$^6$Li interspecies Feshbach resonances
including 13 elastic p-wave resonances and 6 broad d-wave resonances of
$^{41}$K atoms in different spin-state combinations at fields up to 600~G.
Multi-channel quantum defect theory calculation is performed to assign these
resonances and the results show perfect agreement with experimental values
after improving input parameters. The observed broad p- and d- wave resonances
display a full resolved multiplet structure. They may serve as important
simulators to nonzero partial wave dominated physics.",2001.11203v1
2018-07-22,Doubly-resonant-cavity electromagnetically induced transparency,"We present an experimental study on the cavity-atom ensemble system, and
realize the doubly-resonant cavity enhanced electromagnetically induced
transparency, where both the probe and control lasers are resonant with a
Fabry-Perot cavity. We demonstrate the precise frequency manipulating of the
hybrid optical-atomic resonances, through either temperature or cavity length
tuning. In such a system, the control power can be greatly enhanced due to the
cavity, and all-optical switching is achieved with a much lower control laser
power compared to previous studies. A new theoretical model is developed to
describe the effective three-wave mixing process between spin-wave and optical
modes. Interesting non-Hermitian physics are predicted theoretically and
demonstrated experimentally. Such a doubly-resonant cavity-atom ensemble system
without a specially designed cavity can be used for future applications, such
as optical signal storage and microwave-to-optical frequency conversion.",1807.08307v1
2018-08-18,Neutron spin resonance as a probe of Fermi surface nesting and superconducting gap symmetry in Ba$_{0.67}$K$_{0.33}$(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$,"We use inelastic neutron scattering to study energy and wave vector
dependence of the superconductivity-induced resonance in hole-doped
Ba$_{0.67}$K$_{0.33}$(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$ ($x=0,0.08$ with
$T_c\approx 37, 28$ K, respectively). In previous work on electron-doped
Ba(Fe$_{0.963}$Ni$_{0.037}$)$_2$As$_2$ ($T_N=26$ K and $T_c=17$ K), the
resonance is found to peak sharply at the antiferromagnetic (AF) ordering wave
vector ${\bf Q}_{\rm AF}$ along the longitudinal direction, but disperses
upwards away from ${\bf Q}_{\rm AF}$ along the transverse direction. For hole
doped $x=0, 0.08$ without AF order, we find that the resonance displays
ring-like upward dispersion away from ${\bf Q}_{\rm AF}$ along both the
longitudinal and transverse directions. By comparing these results with
calculations using the random phase approximation, we conclude that the
dispersive resonance is a direct signature of isotropic superconducting gaps
arising from nested hole-electron Fermi surfaces.",1808.06108v1
2010-01-20,Precise probing spin wave mode frequencies in the vortex state of circular magnetic dots,"We report on detailed broadband ferromagnetic resonance measurements of
azimuthal and radial spin wave excitations in circular Permalloy dots in the
vortex ground state. Dots with aspect ratio (Beta =height over radius) varied
from 0.03 to 0.1 were explored. We found that for Beta exceeding approximately
0.05, variation of the spin wave eigenfrequencies with Beta deviates from the
predicted dependence. The frequency splitting of two lowest azimuthal modes was
observed. The experimentally observed dependence of the frequency splitting on
beta was reasonably well described by dynamic splitting model accounting the
spin-waves and, vortex gyrotropic mode interaction.",1001.3605v1
2013-07-17,Low-amplitude magnetic vortex core reversal by non-linear interference between azimuthal spin waves and the vortex gyromode,"We demonstrate a non-linear interference due to an active 'dual frequency'
excitation of both, the sub-GHz vortex gyromode and multi-GHz magneto-static
spin waves in ferromagnetic micrometer sized platelets in the vortex state.
When the sub-GHz vortex gyromode is excited simultaneously a significant
broadband reduction of the switching threshold for spin wave mediated vortex
core reversal is observed in both, experiments and micromagnetic simulations.
Consequently, the magnetic field amplitudes required for vortex core reversal
can be lowered by nearly one order of magnitude. Moreover, additional spin wave
resonance frequencies are found which emerge only if the vortex gyromode is
actively excited simultaneously which can be explained by frequency doubling
and by the broken symmetry of the vortex state.",1307.4548v1
2020-03-23,Spin-wave gap collapse in Rh-doped Sr2IrO4,"We use resonant inelastic x-ray scattering (RIXS) at the Ir L3 edge to study
the effect of hole doping upon the Jeff=1/2 Mott-insulating state in Sr2IrO4,
via Rh replacement of the Ir site. The spin-wave gap, associated with XY-type
spin-exchange anisotropy, collapses with increasing Rh content, prior to the
suppression of the Mott-insulating state and in contrast to electron doping via
La substitution of the Sr site. At the same time, despite heavy damping, the
d-d excitation spectra retain their overall amplitude and dispersion character.
A careful study of the spin-wave spectrum reveals that deviations from the
J1-J2-J3 Heisenberg used to model the pristine system disappear at intermediate
doping levels. These findings are interpreted in terms of a modulation of Ir-Ir
correlations due to the influence of Rh impurities upon nearby Ir wave
functions, even as the single-band Jeff=1/2 model remains valid up to full
carrier delocalization. They underline the importance of the transition metal
site symmetry when doping pseudospin systems such as Sr2IrO4.",2003.10343v1
2021-10-04,Lumped circuit model for inductive antenna spin-wave transducers,"We derive a lumped circuit model for inductive antenna spin-wave transducers
in the vicinity of a ferromagnetic medium. The model considers the antenna's
Ohmic resistance, its inductance, as well as the additional inductance due to
the excitation of ferromagnetic resonance or spin waves in the ferromagnetic
medium. As an example, the additional inductance is discussed for a wire
antenna on top of a ferromagnetic waveguide, a structure that is characteristic
for many magnonic devices and experiments. The model is used to assess the
scaling properties and the energy efficiency of inductive antennas. Issues
related to scaling antenna transducers to the nanoscale and possible solutions
are also addressed.",2110.01318v3
2022-04-27,Magnetochiral Properties of Spin Waves Existing in Nanotubes with Axial and Circumferential Magnetization,"We report experimental studies of spin-wave excitations in individual 22 nm
thick Ni80Fe20 nanotubes with diameters of about 150 nm by means of Brillouin
light-scattering (BLS) spectroscopy. Irradiated by microwaves we resolve sets
of discrete resonances in the center of nanotubes ranging from 2.5 to 12.5 GHz.
Comparing to a recent theoretical work and micromagnetic simulations, we
identify different characteristic eigenmodes depending on the axial, mixed or
vortex configuration. The mixed and vortex states give rise to modes with
helical phase profiles substantiating an unusual nature of modes attributed to
non-reciprocal spin waves. Our findings provide microscopic insight into
tubular spin-wave nanocavities and magnetochiral effects for 3D nanomagnonics.",2204.12995v1
2022-05-17,Polarization manipulation of giant photonic spin Hall effect using wave-guiding effect,"In plasmonic systems, the enhanced photonic spin Hall effect (PSHE) was
previously possible only for horizontal polarization. By employing the
wave-guiding surface plasmon resonance (WG-SPR) effect, we report a giant
photonic spin Hall effect (G-PSHE) of reflected light for both horizontal and
vertical polarization waves. We investigated the polarization-manipulated
G-PSHE in the Kretschmann configuration with an additional glass dielectric
layer. This additional dielectric layer allowed us to achieve millimeter-scale
(more than 2 mm to sub-millimeter) G-PSHE. We achieved polarization
manipulation by designing novel structures employing wave-guiding and SPR
theory. Using a simulation study, we investigated the impact of an additional
thin dielectric layer on G-PSHE. This study enables the potential application
of both horizontal and vertical polarization-based quantum devices and sensors
for which light spin plays a pivotal role.",2205.08258v1
2014-12-12,Spin waves in micro-structured yttrium iron garnet nanometer-thick films,"We investigated the spin-wave propagation in a micro-structured yttrium iron
garnet waveguide of $40$ nm thickness. Utilizing spatially-resolved Brillouin
light scattering microscopy, an exponential decay of the spin-wave amplitude of
$(10.06 \pm 0.83)$ $\mu$m was observed. This leads to an estimated Gilbert
damping constant of $\alpha=(8.79\pm 0.73)\times 10^{-4}$, which is larger than
damping values obtained through ferromagnetic resonance measurements in
unstructured films. The theoretically calculated spatial interference of
waveguide modes was compared to the spin-wave pattern observed experimentally
by means of Brillouin light scattering spectroscopy.",1412.4032v1
2022-11-20,Spin-wave spectra in antidot lattice with inhomogeneous perpendicular magnetocrystalline anisotropy,"Magnonic crystals are structures with periodically varied magnetic properties
that are used to control collective spin-wave excitations. With micromagnetic
simulations, we study spin-wave spectra in a 2D antidot lattice based on a
multilayered thin film with perpendicular magnetic anisotropy (PMA). We show
that the modification of the PMA near the antidot edges introduces interesting
modifications to the spin-wave spectra, even in a fully saturated state. In
particular, the spectra split in two types of excitations, bulk modes with
amplitude concentrated in a homogeneous part of antidot lattice, and edge modes
with an amplitude localized in the rims of reduced PMA at the antidot edges.
Their dependence on the geometrical or material parameters is distinct but at
resonance conditions fulfilled, we found strong hybridization between bulk and
radial edge modes. Interestingly, the hybridization between the fundamental
modes in bulk and rim is of magnetostatic origin but the exchange interactions
determine the coupling between higher-order radial rim modes and the
fundamental bulk mode of the antidot lattice.",2211.11002v1
1998-05-09,The resonance peak in cuprate superconductors,"We pursue the consequences of a theory in which the resonance peak observed
in inelastic neutron scattering (INS) experiments on underdoped and optimally
doped YBa$_2$Cu$_3$O$_{6+x}$ compounds arises from a spin-wave excitation. We
find that it is heavily damped, and thus almost not observable, in the normal
state, but becomes visible in the superconducting state due to the drastic
decrease in spin damping. We show that a spin-fermion model correctly describes
the temperature dependence of the peak position for YBa$_2$Cu$_3$O$_7$, as well
as the doping dependence of the peak position and of the integrated intensity.
We explain why no resonance peak has been observed in La$_{2-x}$Sr$_x$CuO$_4$,
and make several predictions concerning resonance peaks in other cuprate
superconductors.",9805107v1
2002-09-12,High field magnetic resonant properties of beta'-(ET)2SF5CF2SO3,"A systematic electron spin resonance (ESR) investigation of the low
temperature regime for the (ET)2SF5CF2SO3 system was performed in the frequency
range of ~200-700 GHz, using backward wave oscillator sources, and at fields up
to 25 T. Newly acquired access to the high frequency and fields shows
experimental ESR results in agreement with the nuclear magnetic resonance (NMR)
investigation, revealing evidence that the transition seen at 20 K is not of
conventional spin-Peierls order. A significant change of the spin resonance
spectrum in beta'-(ET)2SF5CF2SO3 at low temperatures, indicates a transition
into a three-dimensional-antiferromagnetic (3D AFM) phase.",0209295v4
2019-06-21,Neutrino flavor oscillations and spin rotation in matter and electromagnetic field,"We obtain a relativistically covariant wave equation for neutrinos in dense
matter and electromagnetic field, which describes both flavor oscillations and
neutrino spin rotation. Using this equation we construct a quasi-classical
theory of these phenomena. We obtain the probabilities of arbitrary spin-flavor
transitions assuming the external conditions to be constant. We demonstrate
that the resonance behavior of the transition probabilities is possible only
when the neutrino flavor states cannot be described as superpositions of the
mass eigenstates. We discover that a resonance, which is similar to the
Mikheev-Smirnov-Wolfenstein resonance, takes place for neutrinos in magnetic
field due to the transition magnetic moments. This resonance gives an
opportunity to determine, whether neutrinos are Dirac or Majorana particles.",1906.09351v2
2019-05-31,Bandwidth analysis of AC magnetic field sensing based on electronic spin double resonance of nitrogen-vacancy centers in diamond,"Recently we have demonstrated AC magnetic field sensing scheme using a simple
continuous-wave optically detected magnetic resonance of nitrogen-vacancy
centers in diamond [Appl. Phys. Lett. 113, 082405 (2018)]. This scheme is based
on electronic spin double resonance excited by continuous microwaves and
radio-frequency (RF) fields. Here we measured and analyzed the double resonance
spectra and magnetic field sensitivity for various frequencies of microwaves
and RF fields. As a result, we observed a clear anticrossing of RF-dressed
electronic spin states in the spectra and estimated the bandwidth to be
approximately 5 MHz at the center frequency of 9.9 MHz.",1905.13671v1
2006-01-09,Dynamical spin susceptibility and the resonance peak in the pseudogap region of the underdoped cuprate superconductors,"We present a study of the dynamical spin susceptibility in the pseudogap
region of the high-T$_c$ cuprate superconductors. We analyze and compare the
formation of the so-called resonance peak, in three different ordered states:
the $d_{x^2-y^2}$-wave superconducting (DSC) phase, the $d$-density wave (DDW)
state, and a phase with coexisting DDW and DSC order. An analysis of the
resonance's frequency and momentum dependence in all three states reveals
significant differences between them. In particular, in the DDW state, we find
that a nearly dispersionless resonance excitation exists only in a narrow
region around ${\bf Q}=(\pi,\pi)$. At the same time, in the coexisting DDW and
DSC state, the dispersion of the resonance peak near ${\bf Q}$ is significantly
changed from that in the pure DSC state. Away from $(\pi,\pi)$, however, we
find that the form and dispersion of the resonance excitation in the coexisting
DDW and DSC state and pure DSC state are quite similar. Our results demonstrate
that a detailed experimental measurement of the resonance's dispersion allows
one to distinguish between the underlying phases - a DDW state, a DSC state, or
a coexisting DDW and DSC state - in which the resonance peak emerges.",0601173v2
2015-01-09,Three-body nature of $N^{\bf *}$ and $Δ^*$ resonances from sequential decay chains,"The $N\pi^0\pi^0$ decays of positive-parity $N^*$ and $\Delta^*$ resonances
at about 2\,GeV are studied at ELSA by photoproduction of two neutral pions off
protons. The data reveal clear evidence for several intermediate resonances:
$\Delta(1232)$, $N(1520){3/2^-}$, and $N(1680){5/2^+}$, with spin-parities
$J^P=3/2^+$, $3/2^-$, and $5/2^+$. The partial wave analysis (within the
Bonn-Gatchina approach) identifies $N(1440)1/2^+$ and the $N(\pi\pi)_{\rm
S-wave}$ (abbreviated as $N\sigma$ here) as further isobars, and assigns the
final states to the formation of nucleon and $\Delta$ resonances and to
non-resonant contributions. We observe the known $\Delta(1232)\pi$ decays of
$\Delta(1910)1/2^+$, $\Delta(1920)3/2^+$, $\Delta(1905)5/2^+$,
$\Delta(1950)7/2^+$, and of the corresponding spin-parity series in the nucleon
sector, $N(1880)1/2^+$, $N(1900)3/2^+$, $N(2000)5/2^+$, and $N(1990)7/2^+$. For
the nucleon resonances, these decay modes are reported here for the first time.
Further new decay modes proceed via $N(1440)1/2^+\pi$, $N(1520)3/2^-\pi$,
$N(1680)5/2^+\pi$, and $N\sigma$. The latter decay modes are observed in the
decay of $N^*$ resonances and at most weakly in $\Delta^*$ decays. It is argued
that these decay modes provide evidence for a 3-quark nature of $N^*$
resonances rather than a quark-diquark structure.",1501.02094v1
2006-06-09,Magnetic resonance studies of the fundamental spin-wave modes in individual submicron Cu/NiFe/Cu perpendicularly magnetized disks,"Spin wave spectra of perpendicularly magnetized disks with trilayers
consisting of a 100 nm permalloy (Py) layer sandwiched by two Cu layers of 30
nm, are measured individually with a Magnetic Resonance Force Microscope
(MRFM). It is demonstrated by 3D micromagnetic simulations that in disks having
sub-micron size diameters, the lowest energy spin wave mode of the saturated
state is not spatially uniform but rather is localized at the center of the
Py/Cu interface in the region of a minimum demagnetizing field.",0606245v3
2007-05-07,Stability of spinor Fermi gases in tight waveguides,"The two and three-body correlation functions of the ground state of an
optically trapped ultracold spin-1/2 Fermi gas (SFG) in a tight waveguide (1D
regime) are calculated in the plane of even and odd-wave coupling constants,
assuming a 1D attractive zero-range odd-wave interaction induced by a 3D p-wave
Feshbach resonance, as well as the usual repulsive zero-range even-wave
interaction stemming from 3D s-wave scattering. The calculations are based on
the exact mapping from the SFG to a ``Lieb-Liniger-Heisenberg'' model with
delta-function repulsions depending on isotropic Heisenberg spin-spin
interactions, and indicate that the SFG should be stable against three-body
recombination in a large region of the coupling constant plane encompassing
parts of both the ferromagnetic and antiferromagnetic phases. However, the
limiting case of the fermionic Tonks-Girardeau gas (FTG), a spin-aligned 1D
Fermi gas with infinitely attractive p-wave interactions, is unstable in this
sense. Effects due to the dipolar interaction and a Zeeman term due to a
resonance-generating magnetic field do not lead to shrinkage of the region of
stability of the SFG.",0705.0937v1
2008-02-22,Microwave spectral analysis by means of non-resonant parametric recovery of spin-wave signals in a thin magnetic film,"We report on the storage and non-resonant parametric recovery of microwave
signals carried by a dipolar surface spin-wave pulse in a thin ferrimagnetic
film. The information about the intensity of the spectral components of the
signal within a narrow frequency band is saved due to the excitation of a
dipolar-exchange standing spin-wave mode across the film thickness and is
afterwards restored by means of parametric amplification of this mode. The
intensity of the restored signal measured for varying shifts between the signal
carrier frequency and half of the pumping frequency, which is equal to the
frequency of the standing mode, reveals information about the entire frequency
spectrum of the input microwave signal.",0802.3302v1
2010-07-21,Exchange anisotropy pinning of a standing spin wave mode,"Standing spin waves in a thin film are used as sensitive probes of interface
pinning induced by an antiferromagnet through exchange anisotropy. Using
coplanar waveguide ferromagnetic resonance, pinning of the lowest energy spin
wave thickness mode in Ni(80)Fe(20)/Ir(25)Mn(75) exchange biased bilayers was
studied for a range of IrMn thicknesses. We show that pinning of the standing
mode can be used to amplify, relative to the fundamental resonance, frequency
shifts associated with exchange bias. The shifts provide a unique `fingerprint'
of the exchange bias and can be interpreted in terms of an effective
ferromagnetic film thickness and ferromagnet/antiferromagnet interface
anisotropy. Thermal effects are studied for ultra-thin antiferromagnetic
Ir(25)Mn(75) thicknesses, and the onset of bias is correlated with changes in
the pinning fields. The pinning strength magnitude is found to grow with
cooling of the sample, while the effective ferromagnetic film thickness
simultaneously decreases. These results suggest that exchange bias involves
some deformation of magnetic order in the interface region.",1007.3577v1
2020-12-29,Nonreciprocal Multi-mode and Indirect Couplings in Cavity Magnonics,"We investigate the magnon-photon couplings by employing a small magnet within
an irregular resonant cavity, which leads to a desirable nonreciprocity with a
big isolation ratio. Moreover, the higher-order couplings between the spin wave
modes with the polarized photon modes also exhibit the nonreciprocity. These
couplings between polarized photon and spin waves could be regarded as an
indirect multi-modes coupling between the ferromagnetic resonance (FMR) mode
and spin wave mode magnons mediated by the cavity mode photons. We also derive
a coupling matrix to predict the characteristics of this kind of indirect
coupling. The existence of the indirect couplings broaden the field range of
the nonreciprocity of the system. The achieved nonreciprocal multi-mode
magnon-photon couplings in a single system offer a feasible method to improve
the signal transmission quality.",2012.14765v2
2021-06-14,Mode-sensitive magnetoelastic coupling in phononic-crystal magnomechanics,"Acoustically driven spin-wave resonance in a phononic crystal cavity is
numerically investigated. The designed cavity enables confinement of gigahertz
vibrations in a wavelength-scale point-defect structure and sustains a variety
of resonance modes. Inhomogeneous strain distributions in the modes modify the
magnetostrictive coupling and the spin-wave excitation susceptible to an
external field orientation. In particular, a monopole-like mode in the cavity
having a near-symmetrical pattern shows a subwavelength-scale mode volume and
can provide a versatile acoustic excitation scheme independent on field-angle
variation. Thus, the phononic-crystal platform offers an alternative approach
to acoustically control the spin-wave dynamics with ultrasmall and
inhomogeneous mode structures, which will be a key technology to integrate and
operate large-scale magnomechanical circuits.",2106.07180v1
2022-01-26,Nonlinear magnon polaritons,"We experimentally and theoretically demonstrate that nonlinear spin-wave
interactions suppress the hybrid magnon-photon quasiparticle or ""magnon
polariton"" in microwave spectra of an yttrium iron garnet film detected by an
on-chip split-ring resonator. We observe a strong coupling between the Kittel
and microwave cavity modes in terms of an avoided crossing as a function of
magnetic fields at low microwave input powers, but a complete closing of the
gap at high powers. The experimental results are well explained by a
theoretical model including the three-magnon decay of the Kittel magnon into
spin waves. The gap closure originates from the saturation of the ferromagnetic
resonance above the Suhl instability threshold by a coherent back reaction from
the spin waves.",2201.10889v2
2013-02-18,Resonant-plane locking and spin alignment in stellar-mass black-hole binaries: a diagnostic of compact-binary formation,"We study the influence of astrophysical formation scenarios on the
precessional dynamics of spinning black-hole binaries by the time they enter
the observational window of second- and third-generation gravitational-wave
detectors, such as Advanced LIGO/Virgo, LIGO-India, KAGRA and the Einstein
Telescope. Under the plausible assumption that tidal interactions are efficient
at aligning the spins of few-solar mass black-hole progenitors with the orbital
angular momentum, we find that black-hole spins should be expected to
preferentially lie in a plane when they become detectable by gravitational-wave
interferometers. This ""resonant plane"" is identified by the conditions
\Delta\Phi=0{\deg} or \Delta\Phi=+/-180{\deg}, where \Delta\Phi is the angle
between the components of the black-hole spins in the plane orthogonal to the
orbital angular momentum. If the angles \Delta \Phi can be accurately measured
for a large sample of gravitational-wave detections, their distribution will
constrain models of compact binary formation. In particular, it will tell us
whether tidal interactions are efficient and whether a mechanism such as mass
transfer, stellar winds, or supernovae can induce a mass-ratio reversal (so
that the heavier black hole is produced by the initially lighter stellar
progenitor). Therefore our model offers a concrete observational link between
gravitational-wave measurements and astrophysics. We also hope that it will
stimulate further studies of precessional dynamics, gravitational-wave template
placement and parameter estimation for binaries locked in the resonant plane.",1302.4442v2
2015-07-20,Distinguishing black-hole spin-orbit resonances by their gravitational wave signatures. II: Full parameter estimation,"Gravitational waves from coalescing binary black holes encode the evolution
of their spins prior to merger. In the post-Newtonian regime and on the
precession timescale, this evolution has one of three morphologies, with the
spins either librating around one of two fixed points (""resonances"") or
circulating freely. In this work we perform full parameter estimation on
resonant binaries with fixed masses and spin magnitudes, changing three
parameters: a conserved ""projected effective spin"" $\xi$ and resonant family
$\Delta\Phi=0,\pi$ (which uniquely label the source), the inclination
$\theta_{JN}$ of the binary's total angular momentum with respect to the line
of sight (which determines the strength of precessional effects in the
waveform), and the signal amplitude. We demonstrate that resonances can be
distinguished for a wide range of binaries, except for highly symmetric
configurations where precessional effects are suppressed. Motivated by new
insight into double-spin evolution, we introduce new variables to characterize
precessing black hole binaries which naturally reflects the timescale
separation of the system and therefore better encode the dynamical information
carried by gravitational waves.",1507.05587v3
2001-09-17,Ferromagnetic resonance in periodic particle arrays,"We report measurements of the ferromagnetic resonance (FMR) spectra of arrays
of submicron size periodic particle arrays of permalloy produced by
electron-beam lithography. In contrast to plane ferromagnetic films, the
spectra of the arrays show a number of additional resonance peaks, whose
position depends strongly on the orientation of the external magnetic field and
the interparticle interaction. Time-dependent micromagnetic simulation of the
ac response show that these peaks are associated with coupled exchange and
dipolar spin wave modes",0109307v1
2011-02-17,Ground State of the Quasi-1D \bvs\ resolved by Resonant Magnetic X-ray Scattering,"Resonant-magnetic x-ray scattering (RMXS) near the vanadium
$L_{2,3}$-absorption edges has been used to investigate the low temperature
magnetic structure of high quality \bvs\ single crystals. Below $T_N$ = 31 K,
the strong resonance revealed a triple-incommensurate magnetic ordering at wave
vector (0.226 0.226 $\xi$) in the hexagonal notation, with $\xi$ = 0.033. The
simulations of the experimental RMXS spectra with a time-dependent density
functional theory indicate an antiferromagnetic order with the spins polarized
along $a$ in the monoclinic structure.",1102.3589v1
2000-08-30,E1 transitions between spin-dipole and Gamow-Teller giant resonances,"The branching ratios for E1 transitions between the spin-dipole (SD) and
Gamow-Teller (GT) giant resonances in $^{90}$Nb and $^{208}$Pb are evaluated.
Assuming the main GT-state has the wave function close to that for the ""ideal""
GT-state, we reduced the problem to calculate the SD and GT strength functions.
These strength functions are evaluated within an extended continuum-RPA
approach.",0008061v1
2012-10-11,Decays and productions via bottomonium for Z_b resonances and other B anti-B molecules,"We discuss decays and productions for the possible molecular states formed by
bottom mesons B (B*) and anti-B (anti-B*). The twin resonances found by Belle,
Zb(10610) and Zb(10650), are such candidates. The spin wave functions of the
molecular states are rearranged into those of heavy and light spin degrees of
freedom by using the re-coupling formulae of angular momentum. By applying the
heavy quark symmetry we derive model independent relations among various decay
and production rates, which can be tested in experiments.",1210.3170v2
2006-12-21,Sound propagation in a Fermi gas near a Feshbach resonance,"Sound waves are observed and studied in an optically trapped degenerate Fermi
gas of spin-up and spin-down atoms with magnetically tunable interactions.
Measurements are made throughout the crossover region, from a
weakly-interacting Fermi gas through the resonant Fermi superfluid regime to a
Bose condensate of dimer molecules. The measured sound velocities test the
equation of state and confirm the universal hypothesis.",0612567v1
2015-08-17,Evidence for resonant scattering of electrons by spin fluctuations in $LaNiO_3/LaAlO_3$ heterostructures grown by pulsed laser deposition,"We present measurements of resistivity $\rho$ in highly oriented $LaNiO_3$
films grown on $LaAlO_3$ substrates by using a pulsed laser deposition
technique. The experimental data are found to follow a universal $\rho (T)
\propto T^{3/2}$ dependence for the entire temperature interval ($20K<T<300K$).
The observed behavior has been attributed to a resonant scattering of electrons
on antiferromagnetic fluctuations (with a characteristic energy $\hbar \omega
_{sf}\simeq 2.1meV$) triggered by spin-density wave propagating through the
interface boundary of $LaNiO_3/LaAlO_3$ sandwich.",1508.04063v1
2017-07-14,Analytic approach to pion-kaon scattering and strange resonances,"We review our analysis of $\pi K$ scattering using forward dispersion
relations. The method yields a set of simple parameterizations that are
compatible with forward dispersion relations up to 1.6 GeV while still
describing the data. Once the partial waves are obtained, we calculate the
poles in the complex plane by means of Pad\'e approximants, thus avoiding a
particular model for the pole parameterization. The resonances calculated below
1.8 GeV are the much debated scalar $\kappa$-meson, nowadays known as
$K_0^*(800)$, the scalar $K_0^*(1430)$, the $K^*(892)$ and $K_1^*(1410)$
vectors, the spin-two $K_2^*(1430)$ as well as the spin-three $K^*_3(1780)$.",1707.04534v1
2018-02-09,Monocrystalline free standing 3D yttrium iron garnet magnon nano resonators,"Nano resonators in which mechanical vibrations and spin waves can be coupled
are an intriguing concept that can be used in quantum information processing to
transfer information between different states of excitation. Until now, the
fabrication of free standing magnetic nanostructures which host long lived spin
wave excitatons and may be suitable as mechanical resonators seemed elusive. We
demonstrate the fabrication of free standing monocrystalline yttrium iron
garnet (YIG) 3D nanoresonators with nearly ideal magnetic properties. The
freestanding 3D structures are obtained using a complex lithography process
including room temperature deposition and lift-off of amorphous YIG and
subsequent crystallization by annealing. The crystallization nucleates from the
substrate and propagates across the structure even around bends over distances
of several micrometers to form e.g. monocrystalline resonators as shown by
transmission electron microscopy. Spin wave excitations in individual
nanostructures are imaged by time resolved scanning Kerr microscopy. The narrow
linewidth of the magnetic excitations indicates a Gilbert damping constant of
only $\alpha = 2.6 \times 10^{-4}$ rivalling the best values obtained for
epitaxial YIG thin film material. The new fabrication process represents a leap
forward in magnonics and magnon mechanics as it provides 3D YIG structures of
unprecedented quality. At the same time it demonstrates a completely new route
towards the fabrication of free standing crystalline nano structures which may
be applicable also to other material systems.",1802.03176v2
2017-02-15,Resonant properties of dipole skyrmions in amorphous Fe/Gd multilayers,"The dynamic response of dipole skyrmions in Fe/Gd multilayer films is
investigated by ferromagnetic resonance measurements and compared to
micromagnetic simulations. We detail thickness and temperature dependent
studies of the observed modes as well as the effects of magnetic field history
on the resonant spectra. Correlation between the modes and the magnetic phase
maps constructed from real-space imaging and scattering patterns allows us to
conclude the resonant modes arise from local topological features such as
dipole skyrmions but does not depend on the collective response of a closed
packed lattice of these chiral textures. Using, micromagnetic modeling, we are
able to quantitatively reproduce our experimental observations which suggests
the existence of localized spin-wave modes that are dependent on the helicity
of the dipole skyrmion. We identify four localized spin wave excitations for
the skyrmions that are excited under either in-plane or out-of-plane r.f.
fields. Lastly we show that dipole skyrmions and non-chiral bubble domains
exhibit qualitatively different localized spin wave modes.",1702.04691v2
2008-04-15,Feedback spin resonance in superconducting CeCu$_2$Si$_2$ and CeCoIn$_5$,"We show that the recently observed spin resonance modes in heavy-fermion
superconductors CeCoIn$_5$ and CeCu$_2$Si$_2$ are magnetic excitons originating
from superconducting quasiparticles. The wave vector ${\bf Q}$ of the resonance
state leads to a powerful criterion for the symmetry and node positions of the
unconventional gap function. The detailed analysis of the superconducting
feedback on magnetic excitations reveals that the symmetry of the
superconducting gap corresponds to a singlet $d_{x^2-y^2}$ state symmetry in
both compounds. In particular this resolves the long-standing ambiguity of the
gap symmetry in CeCoIn$_5$. We demonstrate that in both superconductors the
resonance peak shows a significant dispersion away from ${\bf Q}$ that should
be observed experimentally. Our results suggest a unifying nature of the
resonance peaks in the two heavy-fermion superconductors and in layered
cuprates.",0804.2363v1
2009-06-19,Resonant spin transport through a superconducting double barrier structure,"We study resonant transport through a superconducting double barrier
structure. At each barrier, due to the proximity effect, an incident electron
can either reflect as an electron or a hole (Andreev reflection). Similarly,
transport across the barrier can occur via direct tunneling as electrons as
well as via the crossed Andreev channel, where a hole is transmitted. In the
subgap regime, for a symmetric double barrier system (with low transparency for
each barrier), we find a new T=1/4 resonance (T is the transmission probability
for electrons incident on the double barrier structure) due to interference
between electron and hole wave-functions between the two barriers, in contrast
to a normal double barrier system which has the standard transmission resonance
at T=1. We also point out as an application that the resonant value of T=1/4
can produce pure spin current through the superconducting double barrier
structure.",0906.3679v3
2011-12-06,Highly Polarized Fermi Gases across a Narrow Feshbach Resonance,"We address the phase of a highly polarized Fermi gas across a narrow Feshbach
resonance starting from the problem of a single down spin fermion immersed in a
Fermi sea of up spins. Both polaron and pairing states are considered using the
variational wave function approach, and we find that the polaron to pairing
transition will take place at the BCS side of the resonance, strongly in
contrast to a wide resonance where the transition is located at the BEC side.
For pairing phase, we find out the critical strength of repulsive interaction
between pairs above which the mixture of pairs and fermions will not phase
separate. Therefore, nearby a narrow resonance, it is quite likely that
magnetism can coexist with s-wave BCS superfluidity at large Zeeman field,
which is a remarkable property absent in conventional BCS superconductors (or
fermion pair superfluids).",1112.1282v3
2018-10-01,Arbitrary order exceptional point induced by photonic spin-orbit interaction in coupled resonators,"Many novel properties of non-Hermitian systems are found at or near the
exceptional points-branch points of complex energy surfaces at which
eigenvalues and eigenvectors coalesce. In particular, higher-order exceptional
points can result in optical structures that are ultrasensitive to external
perturbations. Here we show that an arbitrary order exceptional point can be
achieved in a simple system consisting of identical resonators placed near a
waveguide. Unidirectional coupling between any two chiral dipolar states of the
resonators mediated by the waveguide mode leads to the exceptional point, which
is protected by the transverse spin-momentum locking of the guided wave and is
independent of the positions of the resonators. Various analytic response
functions of the resonators at the exceptional points are experimentally
manifested in the microwave regime. The enhancement of sensitivity to external
perturbations near the exceptional point is also numerically and analytically
demonstrated.",1810.00581v2
2021-07-20,Hints of spin-orbit resonances in the binary black hole population,"Binary black hole spin measurements from gravitational wave observations can
reveal the binary's evolutionary history. In particular, the spin orientations
of the component black holes within the orbital plane, $\phi_1$ and $\phi_2$,
can be used to identify binaries caught in the so-called spin-orbit resonances.
In a companion paper, we demonstrate that $\phi_1$ and $\phi_2$ are best
measured near the merger of the two black holes. In this work, we use these
spin measurements to provide the first constraints on the full six-dimensional
spin distribution of merging binary black holes. In particular, we find that
there is a preference for $\Delta \phi = \phi_1 - \phi_2 \sim \pm \pi$ in the
population, which can be a signature of spin-orbit resonances. We also find a
preference for $\phi_1 \sim -\pi/4$ with respect to the line of separation near
merger, which has not been predicted for any astrophysical formation channel.
However, the strength of these preferences depends on our prior choices, and we
are unable to constrain the widths of the $\phi_1$ and $\Delta \phi$
distributions. Therefore, more observations are necessary to confirm the
features we find. Finally, we derive constraints on the distribution of recoil
kicks in the population, and use this to estimate the fraction of merger
remnants retained by globular and nuclear star clusters. We make our spin and
kick population constraints publicly available.",2107.09693v4
2023-03-07,Electron-spin double resonance of nitrogen-vacancy centers in diamond under strong driving field,"The nitrogen-vacancy (NV) center in diamond has been the focus of research
efforts because of its suitability for use in applications such as quantum
sensing and quantum simulations. Recently, the electron-spin double resonance
(ESDR) of NV centers has been exploited for detecting radio-frequency (RF)
fields with continuous-wave optically detected magnetic resonance. However, the
characteristic phenomenon of ESDR under a strong RF field remains to be fully
elucidated. In this study, we theoretically and experimentally analyzed the
ESDR spectra under strong RF fields by adopting the Floquet theory. Our
analytical and numerical calculations could reproduce the ESDR spectra obtained
by measuring the spin-dependent photoluminescence under the continuous
application of microwaves and an RF field for a DC bias magnetic field
perpendicular to the NV axis. We found that anticrossing structures that appear
under a strong RF field are induced by the generation of RF-dressed states
owing to the two-RF-photon resonances. Moreover, we found that $2n$-RF-photon
resonances were allowed by an unintentional DC bias magnetic field parallel to
the NV axis. These results should help in the realization of precise MHz-range
AC magnetometry with a wide dynamic range beyond the rotating wave
approximation regime as well as Floquet engineering in open quantum systems.",2303.03860v2
2007-09-26,Spin-orbital effects in magnetized quantum wires and spin chains,"We present analysis of the interacting quantum wire problem in the presence
of magnetic field and spin-orbital interaction. We show that an interesting
interplay of Zeeman and spin-orbit terms, facilitated by the electron-electron
interaction, results in the spin-density wave (SDW) state when the magnetic
field and spin-orbit axes are orthogonal. We show that this instability is
enhanced in a closely related problem of Heisenberg spin chain with asymmetric
uniform Dzyaloshinskii-Moriya (DM) interaction. Magnetic field in the direction
perpendicular to the DM anisotropy axis results in staggered long-range
magnetic order along the orthogonal to the applied field direction. We explore
consequences of the uniform DM interaction for the electron spin resonance
(ESR) measurements, and point out that they provide way to probe right- and
left-moving excitations of the spin chain separately.",0709.4246v3
2014-01-03,Spin Liquid Condensate of Spinful Bosons,"We introduce the concept of a bosonic spin liquid condensate (SLC), where
spinful bosons in a lattice form a zero-temperature spin disordered charge
condensate that preserves the spin rotation symmetry, but breaks the U(1)
symmetry due to a spinless order parameter with charge one. It has an energy
gap to all the spin excitations. We show that such SLC states can be realized
in a system of spin $S\ge 2$ bosons. In particular, we analyze the SLC phase
diagram in the spin 2 case using a mean-field variational wave function method.
We show there is a direct analogy between the SLC and the
resonating-valence-bond (RVB) state.",1401.0593v2
2003-06-06,Light scattering observations of spin reversal excitations in the fractional quantum Hall regime,"Resonant inelastic light scattering experiments access the low lying
excitations of electron liquids in the fractional quantum Hall regime in the
range $2/5 \geq \nu \geq 1/3$. Modes associated with changes in the charge and
spin degrees of freedom are measured. Spectra of spin reversed excitations at
filling factor $\nu \gtrsim 1/3$ and at $\nu \lesssim 2/5$ identify a structure
of lowest spin-split Landau levels of composite fermions that is similar to
that of electrons. Observations of spin wave excitations enable determinations
of energies required to reverse spin. The spin reversal energies obtained from
the spectra illustrate the significant residual interactions of composite
fermions. At $\nu = 1/3$ energies of spin reversal modes are larger but
relatively close to spin conserving excitations that are linked to activated
transport. Predictions of composite fermion theory are in good quantitative
agreement with experimental results.",0306179v1
2013-04-04,Dynamics of Antiferromagnets Driven by Spin Current,"When a spin-polarized current flows through a ferromagnetic (FM) metal,
angular momentum is transferred to the background magnetization via
spin-transfer torques. In antiferromagnetic (AFM) materials, however, the
corresponding problem is unsolved. We derive microscopically the dynamics of an
AFM system driven by spin current generated by an attached FM polarizer, and
find that the spin current exerts a driving force on the local staggered order
parameter. The mechanism does not rely on the conservation of spin angular
momentum, nor does it depend on the induced FM moments on top the AFM
background. Two examples are studied: (i) A domain wall is accelerated to a
terminal velocity by purely adiabatic effect where the Walker's break-down is
avoided; and (ii) Spin injection modifies the AFM resonance frequency, and spin
current injection triggers spin wave instability of local moments above a
threshold.",1304.1284v5
2018-07-03,Large spin current generation by the spin Hall effect in mixed crystalline phase Ta thin films,"Manipulation of the magnetization in heavy-metal/ferromagnetic bilayers via
the spin-orbit torque requires high spin Hall conductivity of the heavy metal.
We measure inverse spin Hall voltage using a co-planar wave-guide based
broadband ferromagnetic resonance set-up in Py/Ta system with varying
crystalline phase of Ta. We demonstrate a strong correlation between the
measured spin mixing conductance and spin Hall conductivity with the
crystalline phase of Ta thin films. We found a large spin Hall conductivity of
$-2439~(\hbar/e)~\Omega^{-1}$cm$^{-1}$ for low-resistivity (68 $\mu\Omega-$cm)
Ta film having mixed crystalline phase, which we attribute to an extrinsic
mechanism of the spin Hall effect.",1807.01127v1
2006-04-10,Impurity Scattering of Wave Packets on a Lattice,"Quantum transport in a lattice is distinct from its counterpart in continuum
media. Even a free wave packet travels differently in a lattice than in the
continuum. We describe quantum scattering in a one dimensional lattice using
three different formulations and illustrate characteristics of quantum
transport such as resonant transmission. We demonstrate the real time
propagation of a wave packet and its phase shift due to impurity
configurations. Spin-flip scattering is also taken into account in a spin chain
system. We show how individual spins in the chain evolve as a result of a
spin-flip interaction between an incoming electron and a spin chain.",0604261v1
2005-01-01,Equatorial and related non-equilibrium states in magnetization dynamics of ferromagnets: Generalization of Suhl's spin-wave instabilities,"We investigate the nonlinear dynamics underlying the evolution of a 2-D
nanoscale ferromagnetic film with uniaxial anisotropy in the presence of
perpendicular pumping. Considering the associated Landau-Lifshitz spin
evolution equation with Gilbert damping together with Maxwell equation for the
demagnetization field, we study the dynamics in terms of the stereographic
variable. We identify several new fixed points for suitable choice of external
field in a rotating frame of reference. In particular, we identify explicit
equatorial and related fixed points of the spin vector in the plane transverse
to the anisotropy axis when the pumping frequency coincides with the amplitude
of the static parallel field. We then study the linear stability of these novel
fixed points under homogeneous and spin wave perturbations and obtain a
generalized Suhl's instability criterion, giving the condition for exponential
growth of P-modes under spin wave perturbations. Two parameter phase diagrams
(in terms of amplitudes of static parallel and oscillatory perpendicular
magnetic fields) for stability are obtained, which differ qualitatively from
those for the conventional ferromagnetic resonance near thermal equilibrium and
are amenable to experimental tests.",0501002v2
2009-02-21,Inelastic Neutron Scattering Studies of the Spin and Lattice Dynamics in Iron Arsenide Compounds,"Neutrons have played an important role in advancing our understanding of the
pairing mechanism and the symmetry of the superconducting energy gap in the
iron arsenide compounds. Neutron measurements of the phonon density-of-state
are in good agreement with ab initio calculations, provided the magnetism of
the iron atoms is taken into account. However, the predicted superconducting
transition temperatures are less than 1 K, making a conventional phononic
mechanism for superconductivity highly unlikely. Measurements of the spin
dynamics within the spin density wave phase of the parent compounds show
evidence of strongly dispersive spin waves with exchange interactions
consistent with the observed magnetic order. Antiferromagnetic fluctuations
persist in the normal phase of the superconducting compounds, but they are more
diffuse. Below Tc, there is evidence compounds that these fluctuations condense
into a resonant spin excitation at the antiferromagnetic wavevector with an
energy that scales with Tc, consistent with unconventional superconductivity of
extended-s+/- wave symmetry.",0902.3760v1
2023-01-04,Covariant orbital-spin scheme for any spin based on irreducible tensor,"In hadron spectrum physics, the partial wave analysis is a primary method
used to extract properties of hadronic resonances. The covariant orbital-spin
coupling scheme holds unique advantages over other partial wave methods due to
its Lorentz covariant form and determined orbital-spin quantum numbers. This
paper presents a general form of the covariant orbital-spin coupling scheme
based on the irreducible tensor of the homogeneous proper Lorentz group and its
little groups. A systematic procedure for constructing partial wave amplitude
in a Lorentz covariant way is provided, which can be applied to both massive
and massless particles. Specific examples are also included.",2301.01575v3
2000-11-01,Evolution of the resonance and incommensurate spin fluctuations in superconducting YBa$_2$Cu$_3$O$_{6+x}$,"Polarized and unpolarized neutron triple-axis spectrometry was used to study
the dynamical magnetic susceptibility $\chi^{\prime\prime}({\bf q},\omega)$ as
a function of energy ($\hbar\omega$) and wave vector (${\bf q}$) in a wide
temperature range for the bilayer superconductor YBa$_2$Cu$_3$O$_{6+x}$ with
oxygen concentrations, $x$, of 0.45, 0.5, 0.6, 0.7, 0.8, 0.93, and 0.95. The
most prominent features in the magnetic spectra include a spin gap in the
superconducting state, a pseudogap in the normal state, the much-discussed
resonance, and incommensurate spin fluctuations below the resonance. We
establish the doping dependence of the spin gap in the superconducting state,
the resonance energy, and the incommensurability of the spin fluctuations. We
discuss in detail the procedure used for separating the magnetic scattering
from phonon and other spurious effects. In the comparison of our experimental
results with various microscopic theoretical models, particular emphasis was
made to address the similarities and differences in the spin fluctuations of
YBa$_2$Cu$_3$O$_{6+x}$ and La$_{2-x}$Sr$_x$CuO$_4$.",0011019v1
2005-10-07,"Collective Spin and Charge Excitations in (Sr,La)_{14-x}Ca_xCu_{24}O_{41} Quantum Spin Ladders","We study magnetic and electronic properties of two-leg ladder materials. We
observed a two-magnon (2M) resonance which we analyze in terms of symmetry,
relaxation and resonance properties. Our findings were contrasted to 2M Raman
measurements in other magnetic crystals. This comparison made us suggest that
the spin-spin correlations in a self-doped two leg ladder may have a modulated
component besides the exponential decay characteristic of a spin liquid ground
state. We found that the 2M intensity resonates at the Mott gap energy.
Interplane Sr substitution for Ca introduces strong disorder leading to
inhomogeneous broadening of the 2M resonance. The doped holes in the spin
liquid ground state further dilute the magnetic correlations, suppressing the
spectral weight of this excitation. At high Ca concentrations are
superconducting under pressure and hole pairing was proposed to be a robust
feature of doped ladders. The measured dielectric response in the microwave
region, the low energy Raman data, the non-linear transport properties along
with soft x-ray scattering allowed us to conclude that the ground state for a
wide range of Ca concentrations (x < 12) is characterized by charge density
wave correlations. This state seems to be driven not by phonons but by Coulomb
forces and many-body effects. We highlighted the similarity in the finite
frequency Raman response as opposed to the very different behavior of the DC
resistivity between undoped and doped ladders. We found that at high Ca
concentrations the carrier relaxation is characterized by the same large
activation energy (~2000 K) as in the self-doped compound. This observation
prompted us to suggest an unconventional metallic transport driven by
collective electronic response.",0510193v1
2010-04-12,Magnetism in Fe-based superconductors,"In this review, we present a summary of experimental studies of magnetism in
Fe-based superconductors. The doping dependent phase diagram shows strong
similarities to the generic phase diagram of the cuprates. Parent compounds
exhibit magnetic order together with a structural phase transition both of
which are progressively suppressed with doping allowing superconductivity to
emerge. The stripe-like spin arrangement of Fe moments in the magnetically
ordered state shows the identical in-plane structure for the RFeAsO (R=rare
earth) and AFe2As2 (A=Sr, Ca, Ba, Eu and K) parent compounds, notably different
than the spin configuration of the cuprates. Interestingly, Fe1+yTe orders with
a different spin order despite very similar Fermi surface topology. Studies of
the spin dynamics in the parent compounds shows that the interactions are best
characterized as anisotropic three-dimensional (3D) interactions. Despite the
room temperature tetragonal structure, analysis of the low temperature spin
waves under the assumption of a Heisenberg Hamiltonian indicates strong
in-plane anisotropy with a significant next-near neighbor interaction. In the
superconducting state, a resonance, localized in both wavevector and energy is
observed in the spin excitation spectrum as in the cuprates. This resonance is
observed at a wavevector compatible with a Fermi surface nesting instability
independent of the magnetic ordering of the relevant parent compound. The
resonance energy (Er) scales with superconducting transition temperature (TC)
as Er ~4.9 kBTC consistent with the canonical value of ~5 kBTC observed in the
cuprates. Moreover, the relationship between the resonance energy and the
superconducting gap, \Delta, is similar to that observed in many unconventional
superconductors (Er/2\Delta ~ 0.64).",1004.1969v1
2021-02-02,Detecting spins with a microwave photon counter,"Quantum emitters respond to resonant illumination by radiating
electromagnetic fields. A component of these fields is phase-coherent with the
driving tone, while another one is incoherent, consisting of spontaneously
emitted photons and forming the fluorescence signal. Atoms and molecules are
routinely detected by their fluorescence at optical frequencies, with important
applications in quantum technology and microscopy. Spins, on the other hand,
are usually detected by {their coherent response} at radio- or microwave
frequencies, either in continuous-wave or pulsed magnetic resonance. Indeed,
fluorescence detection of spins is hampered {by their low spontaneous emission
rate} and by the lack of single-photon detectors in this frequency range. Here,
using superconducting quantum devices, we demonstrate the detection of a small
ensemble of donor spins in silicon by their fluorescence at microwave frequency
and millikelvin temperatures. We enhance the spin radiative decay rate by
coupling them to a high-quality-factor and small-mode-volume superconducting
resonator, and we connect the device output to a newly-developed microwave
single-photon counter based on a superconducting qubit. We discuss the
potential of fluorescence detection as a novel method for magnetic resonance
spectroscopy of small numbers of spins.",2102.01415v1
2018-07-24,Excitation and control of large amplitude standing magnetization waves,"A robust approach to excitation and control of large amplitude standing
magnetization waves in an easy axis ferromagnetic by starting from a ground
state and passage through resonances with chirped frequency microwave or spin
torque drives is proposed. The formation of these waves involves two stages,
where in the first stage, a spatially uniform, precessing magnetization is
created via passage through a resonance followed by a self-phase-locking
(autoresonance) with a constant amplitude drive. In the second stage, the
passage trough an additional resonance with a spatial modulation of the driving
amplitude yields transformation of the uniform solution into a doubly
phase-locked standing wave, whose amplitude is controlled by the variation of
the driving frequency. The stability of this excitation process is analyzed
both numerically and via Whitham's averaged variational principle.",1807.09033v1
2014-05-07,On kinematical constraints in the hadrogenesis conjecture for the baryon resonance spectrum,"We consider the reaction dynamics of bosons with negative parity and spin $0$
or $1$ and fermions with positive parity and spin $\frac{1}{2}$ or
$\frac{3}{2}$. Such systems are of central importance for the computation of
the baryon resonance spectrum in the hadrogenesis conjecture. Based on a chiral
Lagrangian the coupled-channel partial-wave scattering amplitudes have to be
computed. We study the generic properties of such amplitudes. A decomposition
of the various scattering amplitudes into suitable sets of invariant functions
expected to satisfy Mandelstam's dispersion-integral representation is
presented. Sets are identified that are free from kinematical constraints and
that can be computed efficiently in terms of a novel projection algebra. From
such a representation one can deduce the analytic structure of the partial-wave
amplitudes. The helicity and the conventional angular-momentum partial-wave
amplitudes are kinematically constrained at the Kibble conditions. Therefore an
application of a dispersion-integral representation is prohibitively
cumbersome. We derive covariant partial-wave amplitudes that are free from
kinematical constraints at the Kibble conditions. They correspond to specific
polynomials in the 4-momenta and Dirac matrices that solve the various
Bethe-Salpeter equations in the presence of short-range interactions
analytically.",1405.1597v1
2012-05-18,Theory of L-edge resonant inelastic x-ray scattering for magnetic excitations in two-leg spin ladder,"We study the magnetic excitation spectra of Cu L_{2,3}-edge resonant
inelastic x-ray scattering (RIXS) from the spin-liquid ground state in two-leg
spin ladder cuprates. Applying the projection method developed by the present
authors, we have derived the formulas of the magnetic RIXS spectra, which are
expressed by one- and two-spin correlation functions in the polarization
changing and preserving channels, respectively. The one-spin correlation
function includes both one- and two-triplon excitations and they are picked up
separately by choosing rung wave vector -q_a=\pi and 0, respectively. An
application to Sr_{14}Cu_{24}O_{41} reveals that the calculated RIXS spectrum
captures well the dispersive behavior shown by the lower boundary of
two-triplon continuum. By adjusting the geometrical configuration of the
measurement, one-triplon dispersion around the zone center could be detectable
in the RIXS experiment. The observed weak intensity in the higher energy region
might be attributed to the two-spin correlation function, which could be
detected more clearly at the M_{3}-edge RIXS spectra.",1205.4069v1
2019-03-25,Effect of disorder on the collective excitations of the chiral spin soliton lattice,"We assess the impact of magnetic disorder on the spin excitation spectra of
the chiral helimagnetic crystal $\mathrm{CrNb_3S_6}$ using microwave resonance
spectroscopy. The chiral spin soliton lattice phase (CSL), which is a prototype
of a noncollinear spin system that forms periodically over a macroscopic length
scale, exhibited three resonance modes over a wide frequency range. We found
that the predominance of these modes depended on the degree of magnetic
disorder and that disorder can be suppressed by sweeping the external field via
an ideal helical state at 0~T. The macroscopic coherence of the CSL can be
clearly observed through its collective dynamic behavior. Our study suggests
that magnetic disorder can be used as a mechanism to control spin wave
excitation in noncollinear spin systems.",1903.10129v1
2021-02-01,Magnetoelectric spectroscopy of spin excitations in LiCoPO4,"We have studied spin excitations in a single-domain crystal of
antiferromagnetic LiCoPO4 by THz absorption spectroscopy. By analyzing the
selection rules and comparing the strengths of the absorption peaks in the
different antiferromagnetic domains, we found electromagnons and
magnetoelectric spin resonances besides conventional magnetic-dipole active
spin-wave excitations. Using the sum rule for the magnetoelectric
susceptibility we determined the contribution of the spin excitations to all
the different off-diagonal elements of the static magnetoelectric
susceptibility tensor in zero as well as in finite magnetic fields. We conclude
that the magnetoelectric spin resonances are responsible for the static
magnetoelectric response of the bulk when the magnetic field is along the
x-axis, and the symmetric part of the magnetoelectric tensor with zero diagonal
elements dominates over the antisymmetric components.",2102.00994v1
2024-03-25,Detection of spin pumping free of rectification and thermal artefacts in molecular-based ferromagnetic insulator V[TCNE]x~2,"The molecular-based ferrimagnetic insulator V(TCNE)x has gained recent
interest for efficient spin-wave excitation due to its low Gilbert damping
ratio a=4E-5, and narrow ferromagnetic resonance linewidth f=1Oe. Here we
report a clean spin pumping signal detected on V(TCNE)x/metal bilayer
structures, free from spin rectification or thermal artifacts. On-chip coupling
of microwave power is achieved via a coplanar waveguide to measure the in-plane
angle-dependence of the inverse spin-Hall effect under ferromagnetic resonance
conditions with respect to a constant external magnetic field. A signature of
pure spin current from V(TCNE)x is observed in both platinum and permalloy
metal layers, demonstrating the utility of V(TCNE)x for magnon spintronics
studies in molecule/solid-state heterostructures.",2403.16429v2
2018-10-16,Spin-wave-induced lateral temperature gradient in a YIG thin film/GGG system excited in an ESR cavity,"Lateral thermal gradient of an yttrium iron garnet (YIG) film under the
microwave application in the cavity of the electron spin resonance system (ESR)
was measured at room temperature by fabricating a Cu/Sb thermocouple onto it.
To date, thermal transport in YIG films caused by the Damon-Eshbach mode (DEM)
- the unidirectional spin-wave heat conveyer effect - was demonstrated only by
the excitation using coplanar waveguides. Here we show that effect exists even
under YIG excitation using the ESR cavity - tool often employed to realize spin
pumping. The temperature difference observed around the ferromagnetic resonance
(FMR) field under the 4 mW microwave power peaked at 13 mK. The observed
thermoelectric signal indicates the imbalance of the population between the
DEMs that propagate near the top and bottom surfaces of the YIG film. We
attribute the DEM population imbalance to the different magnetic damping near
the top and bottom YIG surfaces. Additionally, the spin wave dynamics of the
system were investigated using the micromagnetic simulations. The micromagnetic
simulations confirmed the existence of the DEM imbalance in the system with the
increased Gilbert damping at one of the YIG interfaces. The reported results
are indispensable for the quantitative estimation of the electromotive force in
the spin-charge conversion experiments using ESR cavities.",1810.06875v1
2019-12-11,Coherent transfer of spin angular momentum by evanescent spin waves within antiferromagnetic NiO,"Insulating antiferromagnets are efficient and robust conductors of spin
current. To realise the full potential of these materials within spintronics,
the outstanding challenges are to demonstrate scalability down to nanometric
lengthscales and the transmission of coherent spin currents. Here, we report
the coherent transfer of spin angular momentum by excitation of evanescent spin
waves of GHz frequency within antiferromagnetic NiO at room temperature. Using
element-specific and phase-resolved x-ray ferromagnetic resonance, we probe the
injection and transmission of ac spin current, and demonstrate that insertion
of a few nanometre thick epitaxial NiO(001) layer between a ferromagnet and
non-magnet can even enhance the flow of spin current. Our results pave the way
towards coherent control of the phase and amplitude of spin currents at the
nanoscale, and enable the realization of spin-logic devices and spin current
amplifiers that operate at GHz and THz frequencies.",1912.05621v1
2023-03-04,Quantum sensing of paramagnetic spins in liquids with spin qubits in hexagonal boron nitride,"Paramagnetic ions and radicals play essential roles in biology and medicine,
but detecting these species requires a highly sensitive and ambient-operable
sensor. Optically addressable spin color centers in 3D semiconductors have been
used for detecting paramagnetic spins as they are sensitive to the spin
magnetic noise. However, the distance between spin color centers and target
spins is limited due to the difficulty of creating high-quality spin defects
near the surface of 3D materials. Here, we show that spin qubits in hexagonal
boron nitride (hBN), a layered van der Waals (vdW) material, can serve as a
promising sensor for nanoscale detection of paramagnetic spins in liquids. We
first create shallow spin defects in close proximity to the hBN surface, which
sustain high-contrast optically detected magnetic resonance (ODMR) in liquids.
Then we demonstrate sensing spin noise of paramagnetic ions in water based on
spin relaxation measurements. Finally, we show that paramagnetic ions can
reduce the contrast of spin-dependent fluorescence, enabling efficient
detection by continuous wave ODMR. Our results demonstrate the potential of
ultrathin hBN quantum sensors for chemical and biological applications.",2303.02326v1
2021-12-21,Fast long-wavelength exchange spin waves in partially-compensated Ga:YIG,"Spin waves in yttrium iron garnet (YIG) nano-structures attract increasing
attention from the perspective of novel magnon-based data processing
applications. For short wavelengths needed in small-scale devices, the group
velocity is directly proportional to the spin-wave exchange stiffness constant
$\lambda_\mathrm{ex}$. Using wave vector resolved Brillouin Light Scattering
(BLS) spectroscopy, we directly measure $\lambda_\mathrm{ex}$ in Ga-substituted
YIG thin films and show that it is about three times larger than for pure YIG.
Consequently, the spin-wave group velocity overcomes the one in pure YIG for
wavenumbers $k > 4$ rad/$\mu$m, and the ratio between the velocities reaches a
constant value of around 3.4 for all $k > 20$ rad/$\mu$m. As revealed by
vibrating-sample magnetometry (VSM) and ferromagnetic resonance (FMR)
spectroscopy, Ga:YIG films with thicknesses down to 59 nm have a low Gilbert
damping ($\alpha < 10^{-3}$), a decreased saturation magnetization $\mu_0
M_\mathrm{S}~\approx~20~$mT and a pronounced out-of-plane uniaxial anisotropy
of about $\mu_0 H_{\textrm{u1}} \approx 95 $ mT which leads to an out-of-plane
easy axis. Thus, Ga:YIG opens access to fast and isotropic spin-wave transport
for all wavelengths in nano-scale systems independently of dipolar effects.",2112.11348v1
2015-12-24,Ultra-High Cooperativity Interactions between Magnons and Resonant Photons in a YIG sphere,"Resonant photon modes of a 5mm diameter YIG sphere loaded in a cylindrical
cavity in the 10-30GHz frequency range are characterised as a function of
applied DC magnetic field at millikelvin temperatures. The photon modes are
confined mainly to the sphere, and exhibited large mode filling factors in
comparison to previous experiments, allowing ultrastrong coupling with the
magnon spin wave resonances. The largest observed coupling between photons and
magnons is $2g/2\pi=7.11$ GHz for a 15.5 GHz mode, corresponding to a
cooperativity of $C=1.51\pm0.47\times10^7$. Complex modifications beyond a
simple multi-oscillator model, of the photon mode frequencies were observed
between 0 and 0.1 Tesla. Between 0.4 to 1 Tesla, degenerate resonant photon
modes were observed to interact with magnon spin wave resonances with different
couplings strengths, indicating time reversal symmetry breaking due to the
gyrotropic permeability of YIG. Bare dielectric resonator mode frequencies were
determined by detuning magnon modes to significantly higher frequencies with
strong magnetic fields. By comparing measured mode frequencies at 7 Tesla with
Finite Element modelling, a bare dielectric permittivity of $15.96\pm0.02$ of
the YIG crystal has been determined at about $20$ mK.",1512.07773v5
2024-02-07,Anatomy of localized edge modes in laterally coupled waveguides,"We present a systematic micromagnetic study of standing spin-wave modes in
infinitely long Permalloy strips with rectangular cross-section. Using a
finite-element dynamic-matrix method, we first calculate the eigenfrequencies
and the corresponding eigenvectors (mode profiles), as a function of the
in-plane magnetic field applied across the strip. The ferromagnetic resonance
spectra is computed from the mode profiles, assuming a homogeneous
radio-frequency excitation, equivalently to an experimental ferromagnetic
resonance measurement. The investigation of the field-dependent mode profiles
enables for the classification of the observed resonances, here focusing mostly
on the true edge mode localized at the vicinity of strip edges. Furthermore, we
study the mode localization in pairs of 50-nm-thick Permalloy strips as a
function of the strip width and their lateral separation. For closely spaced
strips, the spatial profile of the quasi-uniform mode is substantially modified
due to a significant hybridization with the edge-localized standing spin-wave
modes of the neighbouring strip. We show that a wide-range-tunability of the
localized edge-mode resonances can be achieved with a precise control of the
magnetostatic coupling between the strips. Extreme sensitivity of the edge mode
frequency on the bias field demonstrates a potential of the edge resonances for
field sensing. Furthermore, for narrow strips (~100 nm in width), due to the
reduced number of the allowed confined modes, a field-controllable switching
between the resonances localized either in the strip center or at the edges of
the strips can be achieved.",2402.04715v1
2015-03-23,Neutron spin resonance as a probe of superconducting gap anisotropy in partially detwinned electron underdoped NaFe$_{0.985}$Co$_{0.015}$As,"We use inelastic neutron scattering (INS) to study the spin excitations in
partially detwinned NaFe$_{0.985}$Co$_{0.015}$As which has coexisting static
antiferromagnetic (AF) order and superconductivity ($T_c=15$ K, $T_N=30$ K). In
previous INS work on a twinned sample, spin excitations form a dispersive sharp
resonance near $E_{r1}=3.25$ meV and a broad dispersionless mode at $E_{r1}=6$
meV at the AF ordering wave vector ${\bf Q}_{\rm AF}={\bf Q}_1=(1,0)$ and its
twinned domain ${\bf Q}_2=(0,1)$. For partially detwinned
NaFe$_{0.985}$Co$_{0.015}$As with the static AF order mostly occurring at ${\bf
Q}_{\rm AF}=(1,0)$, we still find a double resonance at both wave vectors with
similar intensity. Since ${\bf Q}_1=(1,0)$ characterizes the explicit breaking
of the spin rotational symmetry associated with the AF order, these results
indicate that the double resonance cannot be due to the static and fluctuating
AF orders, but originate from the superconducting gap anisotropy.",1503.06737v3
2019-09-05,Extraction of Dzyaloshinksii-Moriya interaction from propagating spin waves validated,"The interfacial Dzyaloshinksii-Moriya interaction (iDMI) is of great interest
in thin-film magnetism because of its ability to stabilize chiral spin
textures. It can be quantified by investigating the frequency non-reciprocity
of oppositely propagating spin waves. However, as the iDMI is an interface
interaction the relative effect reduces when the films become thicker making
quantification more difficult. Here, we utilize all-electrical Propagating Spin
Wave Spectroscopy (PSWS) to disentangle multiple contributions to spin wave
frequency non-reciprocity to determine the iDMI. This is done by investigating
non-reciprocities across a wide range of magnetic layer thicknesses (from 4 to
26 nm) in Pt/Co/Ir, Pt/Co/Pt, and Ir/Co/Pt stacks. We find the expected sign
change in the iDMI when inverting the stack order, and a negligible iDMI for
the symmetric Pt/Co/Pt. We additionally extract a difference in surface
anisotropies and find a large contribution due to the formation of different
crystalline phases of the Co, which is corroborated using nuclear magnetic
resonance and high-resolution transmission-electron-microscopy measurements.
These insights will open up new avenues to investigate, quantify and
disentangle the fundamental mechanisms governing the iDMI, and pave a way
towards engineered large spin-wave non-reciprocities for magnonic applications.",1909.02467v1
2008-04-10,Theory of magnetic excitations in iron-based layered superconductors,"Based on the effective four-band model we analyze the spin response in the
normal and superconducting states of the Fe-pnictide superconductors. While the
normal state spin excitations are dominated by the continuum of the
interorbital antiferromagnetic fluctuations and the intraband spin density wave
fluctuations, the unconventional superconductivity yields different feedback.
The resonance peak in form of the well-defined spin exciton occurs {\it only}
for the interband scattering at the antiferromagnetic momentum ${\bf Q}_{AFM}$
for the $s_\pm$ (extended s-wave) superconducting order parameter and it
disappears rapidly for ${\bf q} < {\bf Q}_{AFM}$. The resonance feature is
extremely weak for the $d_{x^2 -y^2}$-wave order parameter due to specific
Fermi surface topology of these compounds. The essential difference between
$s_\pm$-wave and $d_{x^2 -y^2}$-wave symmetries for the magnetic excitations
can be used for experimental determination of the superconducting wave function
symmetry.",0804.1793v2
2017-01-20,Two-magnon excitations in resonant inelastic x-ray scattering studied by spin-density-wave formalism,"We study two-magnon excitations in resonant inelastic x-ray scattering (RIXS)
at the transition-metal $K$-edge. Instead of working with effective Heisenberg
spin models, we work with a Hubbard-type model ($d$-$p$ model) for a typical
insulating cuprate La$_2$CuO$_4$. For the antiferromagnetic ground state within
the spin-density-wave (SDW) mean-field formalism, we calculate the dynamical
correlation function within the random-phase approximation (RPA), and then
obtain two-magnon excitation spectra by calculating the convolution of it.
Coupling between the $K$-shell hole and the magnons in the intermediate state
is calculated by means of diagrammatic perturbation expansion in the Coulomb
interaction. Calculated momentum dependence of RIXS spectra agrees well with
that of experiments. A notable difference from previous calculations based on
the Heisenberg spin models is that RIXS spectra have a large two-magnon weight
near the zone center, which may be confirmed by further careful high-resolution
experiments.",1701.05684v2
2017-03-13,A model for the neutron resonance in HgBa$_{2}$CuO$_{4+δ}$,"We study the spin dynamics of the Resonant Excitonic State (RES) proposed,
within the theory of an emergent SU(2) symmetry, to explain some properties of
the pseudo-gap phase of cuprate superconductors. The RES can be described as a
proliferation of particle-hole patches with an internal modulated structure. We
model the RES modes as a charge order with multiple $2{\bf {p}}_{\text{F}}$
ordering vectors, where $2{\bf {p}}_{\text{F}}$ connects two opposite side of
the Fermi surface. This simple modelization enables us to propose a
comprehensive study of the collective mode observed at the antiferromagnetic
(AF) wave vector $\mathbf{Q}=(\pi,\pi)$ by Inelastic Neutron Scattering (INS)
in both superconducting state (SC), but also in the Pseudogap regime. In this
regime, we show that the dynamic spin susceptibility accuses a loss of
coherence terms except at special wave vectors commensurate with the lattice.
We argue that this phenomenon could explain the change of the spin response
shape around $\mathbf{Q}$. We demonstrate that the hole dependence of the RES
spin dynamics is in agreement with the experimental data in
HgBa$_{2}$CuO$_{4+\delta}$.",1703.04442v1
2005-09-07,Doping dependence of spin excitations in the stripe phase of high-Tc superconductors,"Based on the time-dependent Gutzwiller approximation for the extended Hubbard
model we calculate the energy and momentum dependence of spin excitations for
striped ground states. Our starting point correctly reproduces the observed
doping dependence of the incommensurability in La-based cuprates and the
dispersion of magnetic modes in the insulating parent compound. This allows us
to make quantitative predictions for the doping evolution of the dispersion of
magnetic modes in the stripe phase including the energy and intensity of the
resonance peak as well as the velocity of the spin-wave like Goldstone mode. In
the underdoped regime $n_h<1/8$ we find a weak linear dependence of
$\omega_{res}$ on doping whereas the resonance energy significantly shifts to
higher values when the charge concentration in the stripes starts to deviate
from half-filling for $n_h>1/8$. The velocity $c$ is non-monotonous with a
minimum at 1/8 in coincidence with a well known anomaly in $T_c$. Our
calculations are in good agreement with available experimental data. We also
compare our results with analogous computations based on linear spin-wave
theory.",0509175v2
2007-08-06,Dynamical magnetic susceptibility in the lamellar cobaltate superconductor Na_xCoO_2$\cdot y$H_2O,"We systematically analyze the influence of the superconducting gap symmetry
and the electronic structure on the dynamical spin susceptibility in
superconducting Na_xCoO_2$\cdot y$H_2O within a three different models: the
single a_{1g}-band model with nearest-neighbor hoppings, the realistic
three-band t_{2g}-model with, and without e'_g pockets present at the Fermi
surface. We show that the magnetic response in the normal state is dominated by
the incommensurate antiferromagnetic spin density wave fluctuations at large
momenta in agreement with experimental temperature dependence of the
spin-lattice relaxation rate. Also, we demonstrate that the presence or the
absence of the e'_g-pockets at the Fermi surface does not affect significantly
this conclusion. In the superconducting state our results for d_{x^2-y^2}- or
d_{xy}-wave symmetries of the superconducting order parameter are consistent
with experimental data and exclude nodeless $d_{x^2-y^2} + id_{xy}$-wave
symmetry. We further point out that the spin-resonance peak proposed earlier is
improbable for the realistic band structure of Na_xCoO_2$\cdot y$H_2O.
Moreover, even if present the resonance peak is confined to the
antiferromagnetic wave vector and disappears away from it.",0708.0807v2
2016-10-14,Electric-field tunable spin waves in PMN-PT/NiFe heterostructure: experiment and micromagnetic simulations,"We present a comprehensive theoretical and experimental study of
voltage-controlled standing spin waves resonance (SSWR) in PMN-PT/NiFe
multiferroic heterostructures patterned into microstrips. A spin-diode
technique was used to observe ferromagnetic resonance (FMR) mode and SSWR in
NiFe strip mechanically coupled with a piezoelectric substrate. Application of
an electric field to a PMNPT creates a strain in permalloy and thus shifts the
FMR and SSWR fields due to the magnetostriction effect. The experimental
results are compared with micromagnetic simulations and a good agreement
between them is found for dynamics of FMR and SSWR with and without electric
field. Moreover, micromagnetic simulations enable us to discuss the amplitude
and phase spatial distributions of FMR and SSWR modes, which are not directly
observable by means of spin diode detection technique.",1610.04500v1
2017-07-17,Indirect K-edge bimagnon resonant inelastic X-ray scattering spectrum of $α$-FeTe,"We calculate the K-edge indirect bimagnon resonant inelastic X-ray scattering
(RIXS) intensity spectra of the bicollinear antiferromagnetic order known to
occur in the $\alpha$-FeTe chalcogenide system. Utilizing linear spin wave
theory for this large-S spin system we find that the bimagnon spectrum contains
four scattering channels (two intraband and two interband). We find from our
calculations that for suitable energy-momentum combination the RIXS spectra can
exhibit a one-, two- or three- peak structure. The number of peaks provides a
clue on the various bimagnon excitation processes that can be supported both in
and within the acoustic and optical magnon branches of the bicollinear
antiferromagnet. Unlike the RIXS response of the antiferromagnetic or the
collinear antiferromagnetic spin ordering, the RIXS intensity spectrum of the
bicollinear antiferromagnet does not vanish at the magnetic ordering wave
vector $(\pi/2,-\pi/2)$. It is also sensitive to next-next nearest neighbor and
biquadratic coupling interactions. Our predicted RIXS spectrum can be utilized
to understand the role of multi-channel bimagnon spin excitations present in
the $\alpha$-FeTe chalcogenide.",1707.05057v1
2017-12-12,Microwave to optical photon conversion by means of travelling-wave magnons in YIG films,"In this work we study theoretically the efficiency of a travelling magnon
based microwave to optical photon converter for applications in Quantum
Information (QI). The converter employs an epitaxially grown yttrium iron
garnet (YIG) film as the medium for propagation of travelling magnons (spin
waves). The conversion is achieved through coupling of magnons to guided
optical modes of the film. The total microwave to optical photon conversion
efficiency is found to be larger than in a similar process employing a YIG
sphere by at least 4 orders of magnitude. By creating an optical resonator of a
large length from the film (such that the traveling magnon decays before
forming a standing wave over the resonator length) one will be able to further
increase the efficiency by several orders of magnitude, potentially reaching a
value similar to achieved with opto-mechanical resonators. Also, as a spin-off
result, it is shown that isolation of more that 20 dB with direct insertion
losses about 5 dBm can be achieved with YIG film based microwave isolators for
applications in Quantum Information.
  An important advantage of the suggested concept of the QI devices based on
travelling spin waves is a perfectly planar geometry and a possibility of
implementing a the device as a hybrid opto-microwave chip.",1712.04304v2
2021-11-23,Resonant dynamics of skyrmion lattices in thin film multilayers: Localised modes and spin wave emission,"The spectral signatures of magnetic skyrmions under microwave field
excitation are of fundamental interest and can be an asset for high frequency
applications. These topological solitons can be tailored in multilayered thin
films, but the experimental observation of their spin wave dynamics remains
elusive, in particular due to large damping. Here, we study Pt/FeCoB/AlO$_x$
multilayers hosting dense and robust skyrmion lattices at room temperature with
Gilbert damping of $\sim 0.02$. We use magnetic force microscopy to
characterise their static magnetic phases and broadband ferromagnetic resonance
to probe their high frequency response. Micromagnetic simulations reproduce the
experiments with accuracy and allow us to identify distinct resonant modes
detected in the skyrmion lattice phase. Low ($<$ 2 GHz) and intermediate
frequency ($2-8$ GHz) modes involve excitations localised to skyrmion edges in
conjunction with precession of the uniform background magnetisation, while a
high frequency ($>$ 12 GHz) mode corresponds to in-phase skyrmion core
precession emitting spin waves into uniform background with wavelengths in the
50--80 nm range commensurate with the lattice structure. These findings could
be instrumental in the investigation of room temperature wave scattering and
the implementation of novel microwave processing schemes in reconfigurable
arrays of solitons.",2111.11797v2
1999-11-07,ESR investigation on the Breather mode and the Spinon-Breather dynamical crossover in Cu Benzoate,"A new elementary-excitation, the so called ""breather excitation"", is observed
directly by millimeter-submillimeter wave electron spin resonance (ESR) in the
Heisenberg quantum spin-chain Cu benzoate, in which a field-induced gap is
found recently by specific heat and neutron scattering measurements. Distinct
anomalies were found in line width and in resonance field around the ""dynamical
crossover"" regime between the gap-less spinon-regime and the gapped
breather-regime. When the temperature becomes sufficiently lower than the
energy gap, a new ESR-line with very narrow line-width is found, which is the
manifestation of the breather excitation. The non-linear field dependence of
the resonance field agrees well with the theoretical formula of the first
breather-excitation proposed by Oshikawa and Affleck. The present work
establishes experimentally for the first time that a sine-Gordon model is
applicable to explain spin dynamics in a S=1/2 Heisenberg spin chain subjected
to staggered field even in high fields.",9911094v2
2012-06-04,Quantitative cw Overhauser DNP Analysis of Hydration Dynamics,"Liquid state Overhauser Effect Dynamic Nuclear Polarization (ODNP) has
experienced a recent resurgence of interest. In particular, a new manifestation
of the ODNP measurement measures the translational mobility of water within
5-10 \AA\ of an ESR-active spin probe (i.e. the local translational diffusivity
D_{local} near an electron spin resonance active molecule). Such spin probes,
typically stable nitroxide radicals, have been attached to the surface or
interior of macromolecules, including proteins, polymers, and membrane
vesicles. Despite the unique specificity of this measurement, it requires only
a standard X-band (~10 GHz) continuous wave (cw) electron spin resonance (ESR)
spectrometer, coupled with a standard nuclear magnetic resonance (NMR)
spectrometer. Here, we present a set of developments and corrections that allow
us to improve the accuracy of quantitative ODNP and apply it to samples more
than two orders of magnitude lower than were previously feasible.",1206.0510v1
2020-07-10,Nuclear Surface Acoustic Resonance with Spin-Rotation Coupling,"We show that, under an appropriate out-of-plane static magnetic field,
nuclear spins in a thin specimen on a surface acoustic wave (SAW) cavity can be
resonantly excited and detected through spin-rotation coupling. Since such a
SAW cavity can have the quality factor as high as $10^{4}$ and the mode volume
as small as $10^{-2}$ mm$^{3}$ the signal-to-noise ratio in detecting the
resonance is estimated to be quite high. We argue that detecting nuclear spin
resonance of a single flake of an atomically-thin layer of two-dimensional
semiconductor, which has so far been beyond hope with the conventional
inductive method, can be a realistic target with the proposed scheme.",2007.05645v1
2010-02-04,Coherent Manipulation of Individual Electron Spin in a Double Quantum Dot Integrated with a Micro-Magnet,"We report the coherent manipulation of electron spins in a double quantum dot
integrated with a micro-magnet. We performed electric dipole spin resonance
experiments in the continuous wave (CW) and pump-and-probe modes. We observed
two resonant CW peaks and two Rabi oscillations of the quantum dot current by
sweeping an external magnetic field at a fixed frequency. Two peaks and
oscillations are measured at different resonant magnetic field, which reflects
the fact that the local magnetic fields at each quantum dot are modulated by
the stray field of a micro-magnet. As predicted with a density matrix approach,
the CW current is quadratic with respect to microwave (MW) voltage while the
Rabi frequency (\nu_Rabi) is linear. The difference between the \nu_Rabi values
of two Rabi oscillations directly reflects the MW electric field across the two
dots. These results show that the spins on each dot can be manipulated
coherently at will by tuning the micro-magnet alignment and MW electric field.",1002.0897v1
2011-09-01,Diffractive dissociation into $K_sK^{\pm}π^{\mp}π^{-}$ final states,"The COMPASS fixed-target experiment at CERN/SPS is dedicated to the study of
hadron structure and spectroscopy, especially the search for spin-exotic
states. After having started to study the existence of the spin-exotic
$\pi_1(1600)$ resonance in the 2004 pilot-run data, the new 2008/09 data will
enable us to further clarify the situation. Apart from the $\pi_1(1600)$
resonance, also a spin-exotic $\pi_1(2000)$ was reported in the past in the
$f_1(1285)\pi$ decay channel by the E852/BNL experiment, however, this state
still lacks confirmation. We present a first event selection of the
diffractively produced $(K\bar{K}\pi\pi)^{-}$ system showing clean $f_1(1285)$
and $f_1(1420)$ resonances at competing statistics. A partial-wave analysis
started on $f_1(1285)\pi$ and $f_1(1420)\pi$ decay channels will further
complete the search for spin-exotics in the 2008/09 COMPASS data.",1109.0219v1
2012-04-11,Magneto-Electric Coupling in Single Crystal Cu2OSeO3 Studied by a Novel Electron Spin Resonance Technique,"The magneto-electric (ME) coupling on spin-wave resonances in single-crystal
Cu2OSeO3 was studied by a novel technique using electron spin resonance
combined with electric field modulation. An external electric field E induces a
magnetic field component \mu_0 H^i = \gamma E along the applied magnetic field
H with \gamma=0.7(1) \mu T/(V/mm) at 10 K. We found that ME coupling strength
\gamma is temperature dependent and highly anisotropic. \gamma(T) nearly
follows that of spin susceptibility J(T) and rapidly decreases above the Curie
temperature Tc. The ratio \gamma/J monotonically decreases with increasing
temperature without an anomaly at Tc.",1204.2481v2
2019-07-02,Bias-free reconfigurable magnonic phase shifter based on a spin-current controlled ferromagnetic resonator,"Controllable phase modulation plays a pivotal role in the researches of
magnonic logic gates. Here we propose a reconfigurable spin-current controlled
magnonic phase shifter based on a ferromagnetic resonator. The proposed phase
shifter requires no magnetic bias field during operation. The device is
directly configured over the waveguide while keeping the original structure of
the waveguide unaffected. Numerical micromagnetic simulations show that the
phase shifter could yield either a {\pi}-phase or no shift depending on the
magnetization status of the resonator, which can be controlled by a current
pulse. Moreover, the phase-shifting operation could be affected by spin
current. At different input current density, the device could be either used as
a dynamic controlled phase shifter or a spin-wave valve. Finally, a XNOR
magnonic logic gate is demonstrated using the proposed phase shifter. Our work
can be a beneficial step to enhance the functionality and compatibility of the
magnonic logic circuits.",1907.01303v1
2013-01-08,Magnetic anisotropy in hole-doped superconducting Ba 0.67K 0.33Fe 2As2 probed by polarized inelastic neutron scattering,"We use polarized inelastic neutron scattering (INS) to study spin excitations
of optimally hole-doped superconductor Ba$_{0.67}$K$_{0.33}$Fe$_2$As$_{2}$
($T_c=38$ K).
  In the normal state, the imaginary part of the dynamic susceptibility,
$\chi^{\prime\prime}(Q,\omega)$, shows magnetic anisotropy for energies below
$\sim$7 meV with c-axis polarized spin excitations larger than that of the
in-plane component. Upon entering into the superconducting state, previous
unpolarized INS experiments have shown that spin gaps at $\sim$5 and 0.75 meV
open at wave vectors $Q=(0.5,0.5,0)$ and $(0.5,0.5,1)$, respectively, with a
broad neutron spin resonance at $E_r=15$ meV. Our neutron polarization analysis
reveals that the large difference in spin gaps is purely due to different spin
gaps in the c-axis and in-plane polarized spin excitations, resulting resonance
with different energy widths for the c-axis and in-plane spin excitations. The
observation of spin anisotropy in both opitmally electron and hole-doped
BaFe$_2$As$_2$ is due to their proximity to the AF ordered BaFe$_2$As$_2$ where
spin anisotropy exists below $T_N$.",1301.1397v1
2018-01-11,Quantum Spin of Elastic Wave,"Unveiling intrinsic spins of propagating waves usually offers people a
fundamental understanding of the geometrical and topological properties of
waves from classical to quantum aspects. A great variety of research has shown
that transverse waves can possess non-trivial quantum spins and topology
without help of strong wave-matter interaction. However, until now we still
lack essential physical insights about the spin and topological nature of
longitudinal waves. Here, demonstrated by elastic waves we uncover unique
quantum spins for longitudinal waves and the mixed longitudinal-transverse
waves that play essential roles in topological spin-momentum locking. Based on
this quantum spin perspective, several abnormal phenomena beyond pure
transverse waves are attributed to the hybrid spin induced by mixed
longitudinal-transverse waves. The intrinsic hybrid spin reveals the complex
spin essence in elastic waves and advances our understanding about their
fundamental topological properties. We also show these spin-dependent phenomena
can be exploited to control the wave propagation, such as non-symmetric elastic
wave excitation by spin pairs, uni-directional Rayleigh wave and spin-selected
elastic wave routing. These findings are generally applicable for arbitrary
waves with longitudinal and transverse components.",1801.03907v1
2020-03-23,Gravitomagnetic tidal resonance in neutron-star binary inspirals,"A compact binary system implicating at least one rotating neutron star
undergoes gravitomagnetic tidal resonances as it inspirals toward its final
merger. These have a dynamical impact on the phasing of the emitted
gravitational waves. The resonances are produced by the inertial modes of
vibration of the rotating star. Four distinct modes are involved, and the
resonances occur within the frequency band of interferometric
gravitational-wave detectors when the star spins at a frequency that lies
within this band. The resonances are driven by the gravitomagnetic tidal field
created by the companion star; this is described by a post-Newtonian vector
potential, which is produced by the mass currents associated with the orbital
motion. These resonances were identified previously by Flanagan and Racine
[Phys. Rev. D 75, 044001 (2007)], but these authors accounted only for the
response of a single mode, the r-mode, a special case of inertial modes. All
four relevant modes are included in the analysis presented in this paper. The
total accumulated gravitational-wave phase shift is shown to range from
approximately $10^{-2}$ radians when the spin and orbital angular momenta are
aligned, to approximately $10^{-1}$ radians when they are anti-aligned. Such
phase shifts will become measurable in the coming decades with the deployment
of the next generation of gravitational-wave detectors (Cosmic Explorer,
Einstein Telescope); they might even come to light within this decade, thanks
to planned improvements in the current detectors. With good constraints on the
binary masses and spins gathered from the inspiral waveform, the phase shifts
deliver information regarding the internal structure of the rotating neutron
star, and therefore on the equation of state of nuclear matter.",2003.10427v2
2022-04-03,Resonance energy and wave functions of $^{31}$Ne: a calculation using supersymmetric quantum mechanics,"In this communication, we present an efficient method for computation of
energy and wave function of weakly bound nuclei by the application of
supersymmetric quantum mechanics (SSQM) and bound states in continuum (BIC)
technique. As a case study the scheme is implemented to the two-body ($^{30}$Ne
+ n) cluster model calculation of neutron-rich nucleus $^{31}$Ne. Woods-Saxon
central potential with spin-orbit component is used as the core-nucleon
interaction. The two-body Schr\""{o}dinger equation in relative coordinate is
solved numerically to get the energy and wave function of the low-lying bound
states. A one-parameter family of isospectral potential (IP) is constructed
from the bound state solutions following algebra of SSQM to find energies and
wave functions of the resonance states. In addition to the 2p$_{3/2^-}$ (-0.33
MeV) ground state, two bound excited states: s$_{1/2}$ (-0.30 MeV), $p_{1/2}$
(-0.15 MeV) are also obtained. Few low-lying resonance states: f$_{7/2_1}$
(2.57 MeV), f$_{7/2_2}$ (4.59 MeV), f$_{5/2_1}$ (5.58 MeV), p$_{1/2_1}$(1.432
MeV), p$_{1/2_2}$ (4.165 MeV), p$_{3/2_1}$ (1.431 MeV), p$_{3/2_2}$ (4.205 MeV)
are predicted. Among the predicted resonance states, the f$_{7/2^{-}}$ state
having resonance energy $E_R \simeq 4.59$ MeV is in excellent agreement with
the one found in the literature.",2204.01017v1
2018-04-10,Control of Spin-Exchange Interaction between Alkali-Earth Atoms via Confinement-Induced Resonances in a Quasi 1+0 Dimensional System,"A nuclear-spin exchange interaction exists between two ultracold fermionic
alkali-earth (like) atoms in the electronic $^{1}{\rm S}_{0}$ state ($g$-state)
and $^{3}{\rm P}_{0}$ state ($e$-state), and is an essential ingredient for the
quantum simulation of Kondo effect. We study the control of this spin-exchange
interaction for two atoms simultaneously confined in a quasi-one-dimensional
(quasi-1D) tube, where the $g$-atom is freely moving in the axial direction
while the $e$-atom is further localized by an additional axial trap and behaves
as a quasi-zero-dimensional (quasi-0D) impurity. In this system, the two atoms
experience effective-1D spin-exchange interactions in both even and odd partial
wave channels, whose intensities can be controlled by the characteristic
lengths of the confinements via the confinement-induced-resonances (CIRs). In
current work, we go beyond that pure-1D approximation. We model the transverse
and axial confinements by harmonic traps with finite characteristic lengths
$a_\perp$ and $a_z$, respectively, and exactly solve the ""quasi-1D + quasi-0D""
scattering problem between these two atoms. Using the solutions we derive the
effective 1D spin-exchange interaction and investigate the locations and widths
of the even/odd wave CIRs for our system.
  It is found that when the ratio $a_z/a_\perp$ is larger, the CIRs can be
induced by weaker confinements, which are easier to be realized experimentally.
  The comparison between our results and the recent experiment shows that the
two experimentally observed resonance branches of the spin-exchange effect are
due to an even-wave CIR and an odd-wave CIR, respectively. Our results are
advantageous for the control and description of either the effective
spin-exchange interaction or other types of interactions between ultracold
atoms in quasi 1+0 dimensional systems.",1804.03388v3
2024-04-06,The inverse Faraday effect at Mie resonances,"Nowadays, dielectric nanophotonics enables almost lossless resonant
interaction between light and matter at the nanoscale. We show both
theoretically and by electromagnetic simulations, that the peculiar nature of
Mie-resonance induced effective magnetic fields contrasts sharply with the
optomagnetism of smooth bulk materials. Mie resonances produce strongly
nonuniform effective magnetic fields generated by the inverse Faraday effect.
Different orders of optical resonances are characterized by different types of
the effective magnetic field patterns. The number of point-like inverse Faraday
effect sources can be controlled by adjusting the pump wavelength, allowing for
the selective launch of spin waves with submicron wavelengths. A distinguish
feature of the Mie-resonance-induced effective magnetic fields is the vortex
structure that can be used for the magnetic skyrmion generation. The proposed
approach considerably broadens the scope of nanoscale optomagnetism.",2404.04569v1
2005-03-31,Spectroscopy of Magnetic Excitations in Magnetic Superconductors Using Vortex Motion,"In magnetic superconductors a moving vortex lattice is accompanied by an ac
magnetic field which leads to the generation of spin waves. At resonance
conditions the dynamics of vortices in magnetic superconductors changes
drastically, resulting in strong peaks in the dc I-V characteristics at
voltages at which the washboard frequency of vortex lattice matches the spin
wave frequency $\omega_s({\bf g})$, where ${\bf g}$ are the reciprocal vortex
lattice vectors. We show that if washboard frequency lies above the magnetic
gap, peaks in the I-V characteristics in borocarbides and cuprate layered
magnetic superconductors are strong enough to be observed over the background
determined by the quasiparticles.",0504006v1
2006-06-13,Rectification of radio frequency current in ferromagnetic nanowire,"We report the rectification of a constant wave radio frequency (RF) current
by using a single-layer magnetic nanowire; a direct-current voltage is
resonantly generated when the RF current flows through the nanowire. The
mechanism of the rectification is discussed in terms of the spin torque diode
effect reported for magnetic tunnel junction devices and the rectification is
shown to be direct attributable to resonant spin wave excitation by the RF
current.",0606305v2
2009-08-31,Microwave screening by conduction currents in thin magnetic films: application in stripline broadband FMR,"Ferromagnetic resonance in conducting magnetic bilayers was studied using
microstrip transducers. It was found that excitation or suppression of standing
spin waves could be achieved through enhanced inhomogeneity of eddy currents in
the bilayer caused by finite thickness. This effect is observable in films with
thicknesses below the magnetic skin depth and can be used to study standing
spin wave modes in heterostructures.",0908.4443v2
2015-12-06,Conduction-electron spin resonance in two-dimensional structures,"The infuence of the conduction-electron spin magnetization density, induced
in a two-dimensional electron layer by a microwave electromagnetic field, on
the rejection and transmission of the field is considered. Because of the
induced magnetization and electric current, both the electric and magnetic
components of the field should have jumps on the layer. A way to match the
waves on two sides of the layer, valid when the quasi-two-dimensional electron
gas is in the one-mode state, is proposed. By following this way, the
amplitudes of transmitted and rejected waves as well as the absorption
coefficient are evaluated.",1512.01791v1
2020-03-30,Geometric phase of very slow neutrons,"The geometric phase (GP) acquired by a neutron passing through a uniform
magnetic field elucidates a subtle interplay between its spatial and spin
degrees of freedom. In the standard setup using thermal neutrons, the kinetic
energy is much larger than the typical Zeeman split. This causes the spin to
undergo nearly perfect precession around the axis of the magnetic field and the
GP becomes a function only of the corresponding cone angle. Here, we perform a
plane wave analysis of the GP of very slow neutrons, for which the precession
feature breaks down. Purely quantum-mechanical matter wave effects, such as
resonance, reflection, and tunneling, become relevant for the behavior of the
GP in this low energy scattering regime.",2003.13737v1
2019-10-09,Scattering of exchange spin waves from regions of modulated magnetization,"We investigate the reflection coefficient of spin waves propagating in an
ultra-thin ferromagnetic film with regions where saturation magnetization is
modulated. We find analytically and using micromagnetic simulations that there
are transmission resonances that depend on the width of the regions and on the
energy of excitation. Our results resemble the quantum mechanical
Ramsauer-Townsend effect in which an electron with certain energies can
propagate above a potential field without scattering. Our findings are useful
for reconfigurable magnonic devices where the saturation magnetization can be
dynamically controlled via a thermal landscape.",1910.04303v1
2014-01-24,Wavenumber-dependent Gilbert damping in metallic ferromagnets,"New terms to the dynamical equation of magnetization motion, associated with
spin transport, have been reported over the past several years. Each newly
identified term is thought to possess both a real and an imaginary effective
field leading to fieldlike and dampinglike torques on magnetization. Here we
show that three metallic ferromagnets possess an imaginary effective-field term
which mirrors the well-known real effective-field term associated with exchange
in spin waves. Using perpendicular standing spin wave resonance between 2-26
GHz, we evaluate the magnitude of the finite-wavenumber ($k$) dependent Gilbert
damping $\alpha$ in three typical device ferromagnets, Ni$_{79}$Fe$_{21}$, Co,
and Co$_{40}$Fe$_{40}$B$_{20}$, and demonstrate for the first time the presence
of a $k^2$ term as $\Delta\alpha=\Delta\alpha_0+A_{k}\cdot k^2$ in all three
metals. We interpret the new term as the continuum analog of spin pumping,
predicted recently, and show that its magnitude, $A_{k}$=0.07-0.1 nm$^2$, is
consistent with transverse spin relaxation lengths as measured by conventional
(interlayer) spin pumping.",1401.6467v2
2016-09-05,Spin excitations in optimally P-doped BaFe2(As0.7P0.3)2superconductor,"We use inelastic neutron scattering to study temperature and energy
dependence of spin excitations in optimally P-doped BaFe2(As0.7P0.3)2
superconductor (Tc = 30 K) throughout the Brillouin zone. In the undoped state,
spin waves and paramagnetic spin excitations of BaFe2As2 stem from
antiferromagnetic (AF) ordering wave vector QAF= (1/-1,0) and peaks near zone
boundary at (1/-1,1/-1) around 180 meV. Replacing 30% As by smaller P to induce
superconductivity, low-energy spin excitations of BaFe2(As0.7P0.3)2form a
resonance in the superconducting state and high-energy spin excitations now
peaks around 220 meV near (1/-1,1/-1). These results are consistent with
calculations from a combined density functional theory and dynamical mean field
theory, and suggest that the decreased average pnictogen height in
BaFe2(As0.7P0.3)2 reduces the strength of electron correlations and increases
the effective bandwidth of magnetic excitations.",1609.01021v1
2017-11-27,"Magnetic properties, spin waves and interaction between spin excitations and 2D electrons in interface layer in Y3Fe5O12 / AlOx / GaAs-heterostructures","We describe synthesis of submicron Y3Fe5O12 (YIG) films sputtered on
GaAs-based substrates and present results of the investigation of ferromagnetic
resonance (FMR), spin wave propagation and interaction between spin excitations
and 2D electrons in interface layer in YIG / AlOx / GaAs-heterostructures. It
is found that the contribution of the relaxation process to the FMR linewidth
is about 2 % of the linewidth \Delta H. At the same time, for all samples FMR
linewidths are high. Sputtered YIG films have magnetic inhomogeneity, which
gives the main contribution to the FMR linewidth. Transistor structures with
two-dimensional electron gas (2DEG) channels in AlOx / GaAs interface governed
by YIG-film spin excitations are designed. An effective influence of spin
excitations on the current flowing through the GaAs 2DEG channel is observed.
Light illumination results in essential changes in the FMR spectrum. It is
found that an increase of the 2DEG current leads to an inverse effect, which
represents essential changes in the FMR spectrum.",1711.09814v1
2018-03-19,Terahertz radiation by subpicosecond spin-polarized photocurrent originating from Dirac electrons in a Rashba-type polar semiconductor,"The spin-splitting energy bands induced by the relativistic spin-orbit
interaction in solids provide a new opportunity to manipulate the
spin-polarized electrons on the sub-picosecond time scale. Here, we report one
such example in a bulk Rashba-type polar semiconductor BiTeBr. Strong terahertz
electromagnetic waves are emitted after the resonant excitation of the
interband transition between the Rashba-type spin-splitting energy bands with a
femtosecond laser pulse circularly polarized. The phase of the emitted
terahertz waves is reversed by switching the circular polarization. This
suggests that the observed terahertz radiation originates from the
subpicosecond spin-polarized photocurrents, which are generated by the
asymmetric depopulation of the Dirac state. Our result provides a new way for
the current-induced terahertz radiation and its phase control by the circular
polarization of incident light without external electric fields.",1803.06826v1
2020-09-14,Many-Body Phases of a Planar Bose-Einstein Condensate with Cavity-Induced Spin-Orbit Coupling,"We explore the many-body phases of a two-dimensional Bose-Einstein condensate
with cavity-mediated dynamic spin-orbit coupling. By the help of two transverse
non-interfering, counterpropagating pump lasers and a single standing-wave
cavity mode, two degenerate Zeeman sub-levels of the quantum gas are Raman
coupled in a double-$\Lambda$-configuration. Beyond a critical pump strength
the cavity mode is populated via coherent superradiant Raman scattering from
the two pump lasers, leading to the appearance of a dynamical spin-orbit
coupling for the atoms. We identify three quantum phases with distinct atomic
and photonic properties: the normal ``homogeneous'' phase, the superradiant
``spin-helix'' phase, and the superradiant ``supersolid spin-density-wave''
phase. The latter exhibits an emergent periodic atomic density distribution
with an orthorhombic centered rectangular-lattice structure due to the
interplay between the coherent photon scattering into the resonator and the
collision-induced momentum coupling. The transverse lattice spacing of the
emergent crystal is set by the dynamic spin-orbit coupling.",2009.06475v1
2020-10-06,Emergent spin dynamics enabled by lattice interactions in a bicomponent artificial spin ice,"Artificial spin ice (ASI) are arrays on nanoscaled magnets that can serve
both as models for frustration in atomic spin ice as well as for exploring new
spin-wave-based strategies to transmit, process, and store information. Here,
we exploit the intricate interplay of the magnetization dynamics of two
dissimilar ferromagnetic metals arranged on complimentary lattice sites in a
square ASI to effectively modulate the spin-wave properties. We show that the
interaction between the two sublattices results in unique spectra attributed to
each sublattice and we observe inter- and intra-lattice dynamics facilitated by
the distinct magnetization properties of the two materials. The dynamic
properties are systematically studied by angular-dependent broadband
ferromagnetic resonance and confirmed by micromagnetic simulations. We show
that the combination of materials with dissimilar magnetic properties enables
the realization of a wide range of two-dimensional structures potentially
opening the door to new concepts in nanomagnonics.",2010.03008v1
2018-08-26,Intertwined Spin and Orbital Density Waves in MnP Uncovered by Resonant Soft X-ray Scattering,"Unconventional superconductors are often characterized by numerous competing
and even intertwined orders in their phase diagrams. In particular, the
electronic nematic phases, which spontaneously break rotational symmetry and
often simultaneously involve spin, charge and/or orbital orders, appear
conspicuously in both the cuprate and iron-based superconductors. The
fluctuations associated with these phases may provide the exotic pairing glue
that underlies their high-temperature superconductivity. Helimagnet MnP, the
first Mn-based superconductor under pressure, lacks high rotational symmetry.
However our resonant soft X-ray scattering (RSXS) experiment discovers novel
helical orbital density wave (ODW) orders in this three-dimensional,
low-symmetry system, and reveals intertwined ordering phenomena in
unprecedented detail. In particular, a ODW forms with half the period of the
spin order and fully develops slightly above the spin ordering temperature,
their domains develop simultaneously, yet the spin order domains are larger
than those of the ODW, and they cooperatively produce another ODW with 1/3 the
period of the spin order. These observations provide a comprehensive picture of
the intricate interplay between spin and orbital orders in correlated
materials, and they suggest that nematic-like physics ubiquitously exists
beyond two-dimensional and high-symmetry systems, and the superconducting
mechanism of MnP is likely analogous to those of cuprate and iron-based
superconductors.",1808.08562v1
2017-04-21,A new high-temperature quantum spin liquid with polaron spins,"The existence of a quantum spin liquid (QSL) in which quantum fluctuations of
spins are sufficiently strong to preclude spin ordering down to zero
temperature was originally proposed theoretically more than 40 years ago, but
its experimental realisation turned out to be very elusive. Here we report on
an almost ideal spin liquid state that appears to be realized by atomic-cluster
spins on the triangular lattice of a charge-density wave (CDW) state of
1T-TaS$_2$. In this system, the charge excitations have a well-defined gap of
$\sim 0.3$ eV, while nuclear magnetic quadrupole resonance and muon spin
relaxation experiments reveal that the spins show gapless quantum spin liquid
dynamics and no long range magnetic order down to 70~mK. Canonical $T^{2}$
power-law temperature dependence of the spin relaxation dynamics characteristic
of a QSL is observed from 200~K to $T_f= 55$ K. Below this temperature we
observe a new gapless state with reduced density of spin excitations and high
degree of local disorder signifying new quantum spin order emerging from the
QSL.",1704.06450v1
2019-12-16,Neutron Spin Resonance in the Heavily Hole-doped KFe$_{2}$As$_{2}$ Superconductor,"We report high-resolution neutron scattering measurements of the low energy
spin fluctuations of KFe$_{2}$As$_{2}$, the end member of the hole-doped
Ba$_{1-x}$K$_x$Fe$_2$As$_2$ family with only hole pockets, above and below its
superconducting transition temperature $T_c$ ($\sim$ 3.5 K). Our data reveals
clear spin fluctuations at the incommensurate wave vector ($0.5\pm\delta$, 0,
$L$), ($\delta$ = 0.2)(1-Fe unit cell), which exhibit $L$-modulation peaking at
$L=0.5$. Upon cooling to the superconducting state, the incommensurate spin
fluctuations gradually open a spin-gap and form a sharp spin resonance mode.
The incommensurability ($2\delta$ = 0.4) of the resonance mode ($\sim1.2$ meV)
is considerably larger than the previously reported value ($2\delta$
$\approx0.32$) at higher energies ($\ge\sim6$ meV). The determination of the
momentum structure of spin fluctuation in the low energy limit allows a direct
comparison with the realistic Fermi surface and superconducting gap structure.
Our results point to an $s$-wave pairing with a reversed sign between the hole
pockets near the zone center in KFe$_{2}$As$_{2}$.",1912.07220v1
2007-02-21,Frequency- and transverse wave-vector-dependent spin Hall conductivity in two-dimensional electron gas with disorder,"We determine wave number $q$ and frequency $\omega$ dependent spin Hall
conductivity $\sigma_{yx}^s(q, \omega)$ for a disordered two dimensional
electron system with Rashba spin orbit interaction when $\q$ is {\it
transverse} to the electric field. Both the conventional definition of spin
current and its new definition which takes care of the conservation of spins,
have been considered. The spin Hall conductivitivities for both of these
definitions are qualitatively similar. $\sigma_{yx}^s(q, \omega)$ is zero at
$q=0, \omega =0$ and is maximum at $q=0$ and at small but finite $\omega$ whose
value depends on different parameters of the system. Interestingly for $\omega
\to 0$, $\sigma_{yx}^s(q)$ resonates when $\Lambda \simeq L_{so}$ which are the
wavelength $(\Lambda = 2\pi/q)$ of the electric field's spatial variation and
the length for one cycle of spin precession respectively. The sign of the
out-of-plane component of the electrons' spin flips when the sign of electric
field changes due to its spatial variation along transverse direction. It
changes the mode of spin precession from clockwise to anti-clockwise or {\it
vice versa} and consequently a finite spin Hall current flows in the bulk of
the system.",0702487v4
2019-08-02,Tunable pure spin supercurrents and the demonstration of a superconducting spin-wave device,"Recent ferromagnetic resonance experiments and theory of Pt/Nb/Ni8Fe2
proximity-coupled structures strongly suggest that spin-orbit coupling (SOC) in
Pt in conjunction with a magnetic exchange field in Ni8Fe2 are the essential
ingredients to generate a pure spin supercurrent channel in Nb. Here, by
substituting Pt for a perpendicularly magnetized Pt/Co/Pt spin-sink, we are
able to demonstrate the role of SOC, and show that pure spin supercurrent
pumping efficiency across Nb is tunable by controlling the magnetization
direction of Co. By inserting a Cu spacer with weak SOC between Nb and
Pt/(Co/Pt) spin-sink, we also prove that Rashba type SOC is key for forming and
transmitting pure spin supercurrents across Nb. Finally, by engineering these
properties within a single multilayer structure, we demonstrate a prototype
superconducting spin-wave (SW) device in which lateral SW propagation is
gateable via the opening or closing of a vertical pure spin supercurrent
channel in Nb.",1908.00873v3
2021-02-19,Observation of higher-order non-Hermitian skin effect,"Hermitian theories play a major role in understanding the physics of most
phenomena. It has been found only in the past decade that non-Hermiticity
enables unprecedented effects such as exceptional points, spectral
singularities and bulk Fermi arcs. Recent studies further show that
non-Hermiticity can fundamentally change the topological band theory, leading
to the non-Hermitian band topology and non-Hermitian skin effect, as confirmed
in one-dimensional (1D) systems. However, in higher dimensions, these
non-Hermitian effects remain unexplored in experiments. Here, we demonstrate
the spin-polarized, higher-order non-Hermitian skin effect in two-dimensional
(2D) acoustic metamaterials. Using a lattice of coupled whisper-gallery
acoustic resonators, we realize a spinful 2D higher-order topological insulator
(HOTI) where the spin-up and spin-down states are emulated by the
anti-clockwise and clockwise modes, respectively. We find that the
non-Hermiticity drives wave localizations toward opposite edge boundaries
depending on the spin polarizations. More interestingly, for finite systems
with both edge and corner boundaries, the higher-order non-Hermitian skin
effect leads to wave localizations toward two corner boundaries for the bulk,
edge and corner states in a spin-dependent manner. We further show that such a
non-Hermitian skin effect enables rich wave manipulation through the loss
configuration in each unit-cell. The reported spin-dependent, higher-order
non-Hermitian skin effect reveals the interplay between higher-order topology
and non-Hermiticity, which is further enriched by the spin degrees of freedom.
This unveils a new horizon in the study of non-Hermitian physics and the design
of non-Hermitian metamaterials.",2102.09825v1
2023-10-09,Spin susceptibility in interacting two-dimensional semiconductors and bilayer systems at first order: Kohn anomalies and spin density wave ordering,"This work is an analytic theoretical study of a 2D semiconductor with a Fermi
surface that is split by the Zeeman coupling of electron spins to an external
magnetic field in the presence of electron-electron interactions. For the first
time, we calculate the spin susceptibility for long-range and finite-range
interactions diagrammatically, and find a resonant peak structure at the Kohn
anomaly already in first-order perturbation theory. In contrast to the
density-density correlator that is suppressed due to the large electrostatic
energy required to stabilize charge density order, the spin susceptibility does
not suffer from electrostatic screening effects, thus favouring
spin-density-wave order in 2D semiconductors. Our results impose significant
consequences for determining magnetic phases in 2D semiconductors. For example,
a strongly enhanced Kohn anomaly may result in helical ordering of magnetic
impurities due to the RKKY interaction. Furthermore, the spin degree of freedom
can equally represent a layer pseudospin in the case of bilayer materials. In
this case, the external ""magnetic field"" is a combination of layer bias and
interlayer hopping. The sharp peak of the 2D static spin susceptibility may
then be responsible for dipole-density-wave order in bilayer materials at large
enough electron-phonon coupling.",2310.05555v1
2023-12-10,"Magnetoelectric Coupling in Pb(Zr,Ti)O3/CoFeB Nanoscale Waveguides Studied by Propagating Spin-Wave Spectroscopy","This study introduces a method for the characterization of the
magnetoelectric coupling in nanoscale Pb(Zr,Ti)O3/CoFeB thin film composites
based on propagating spin-wave spectroscopy. Finite element simulations of the
strain distribution in the devices indicated that the magnetoelastic effective
field in the CoFeB waveguides was maximized in the Damon - Eshbach
configuration. All-electrical broadband propagating spin-wave transmission
measurements were conducted on Pb(Zr,Ti)O3/CoFeB magnetoelectric waveguides
with lateral dimensions down to 700 nm. The results demonstrated that the
spin-wave resonance frequency can be modulated by applying a bias voltage to
Pb(Zr,Ti)O3. The modulation is hysteretic due to the ferroelastic behavior of
Pb(Zr,Ti)O3. An analytical model was then used to correlate the change in
resonance frequency to the induced magnetoelastic field in the magnetostrictive
CoFeB waveguide. We observe a hysteresis magnetoelastic field strength with
values as large as 5.61 mT, and a non-linear magnetoelectric coupling
coefficient with a maximum value of 1.69 mT/V.",2312.05819v1
2006-10-24,Non-dissipative tidal synchronization in accreting binary white dwarf systems,"We study a non-dissipative hydrodynamical mechanism that can stabilize the
spin of the accretor in an ultra-compact double white dwarf binary. This novel
synchronization mechanism relies on a nonlinear wave interaction spinning down
the background star. The essential physics of the synchronization mechanism is
summarized as follows. As the compact binary coalesces due to gravitational
wave emission, the largest star eventually fills its Roche lobe and accretion
starts. The accretor then spins up due to infalling material and eventually
reaches a spin frequency where a normal mode of the star is resonantly driven
by the gravitational tidal field of the companion. If the resonating mode
satisfies a set of specific criteria, which we elucidate in this paper, it
exchanges angular momentum with the background star at a rate such that the
spin of the accretor locks at this resonant frequency, even though accretion is
ongoing. Some of the accreted angular momentum that would otherwise spin up the
accretor is fed back into the orbit through this resonant tidal interaction.
  Two modes capable of stabilizing the accretor's spin are the l=4,m=2 and
l=5,m=3 CFS unstable hybrid r-modes, which stabilize the spin of the accretor
at frequency 2.6 and 1.5 times the binary's orbital frequency respectively.
Since the stabilization mechanism relies on continuously driving a mode at
resonance, its lifetime is limited since eventually the mode amplitude
saturates due to non-linear mode-mode coupling. Rough estimates of the lifetime
of the effect lie from a few orbits to millions of years.",0610692v2
2013-07-03,General theory of feedback control of a nuclear spin ensemble in quantum dots,"We present a microscopic theory of the nonequilibrium nuclear spin dynamics
driven by the electron and/or hole under continuous wave pumping in a quantum
dot. We show the correlated dynamics of the nuclear spin ensemble and the
electron and/or hole under optical excitation as a quantum feedback loop and
investigate the dynamics of the many nuclear spins as a nonlinear collective
motion. This gives rise to three observable effects: (i) hysteresis, (ii)
locking (avoidance) of the pump absorption strength to (from) the natural
resonance, and (iii) suppression (amplification) of the fluctuation of weakly
polarized nuclear spins, leading to prolonged (shortened) electron spin
coherence time. A single nonlinear feedback function as a ""measurement"" of the
nuclear field operator in the quantum feedback loop is constructed which
determines the different outcomes of the three effects listed above depending
on the feedback being negative or positive. The general theory also helps to
put in perspective the wide range of existing theories on the problem of a
single electron spin in a nuclear spin bath.",1307.0897v1
2014-11-03,Effective potentials and morphological transitions for binary black-hole spin precession,"We derive an effective potential for binary black-hole (BBH) spin precession
at second post-Newtonian order. This effective potential allows us to solve the
orbit-averaged spin-precession equations analytically for arbitrary mass ratios
and spins. These solutions are quasiperiodic functions of time: after a fixed
period the BBH spins return to their initial relative orientations and jointly
precess about the total angular momentum by a fixed angle. Using these
solutions, we classify BBH spin precession into three distinct morphologies
between which BBHs can transition during their inspiral. We also derive a
precession-averaged evolution equation for the total angular momentum that can
be integrated on the radiation-reaction time and identify a new class of
spin-orbit resonances that can tilt the direction of the total angular momentum
during the inspiral. Our new results will help efforts to model and interpret
gravitational waves from generic BBH mergers and predict the distributions of
final spins and gravitational recoils.",1411.0674v2
2014-11-14,Spin Correlations in Quantum Wires,"We consider theoretically spin correlations in an 1D quantum wire with
Rashba-Dresselhaus spin-orbit interaction (RDI). The correlations of
non-interacting electrons display electron-spin resonance at a frequency
proportional to the RDI coupling. Interacting electrons on varying the
direction of external magnetic field transit from the state of Luttinger liquid
(LL) to the spin density wave (SDW) state. We show that the two-time total spin
correlations of these states are significantly different. In the LL the
projection of total spin to the direction of the RDI induced field is conserved
and the corresponding correlator is equal to zero. The correlators of two
components perpendicular to the RDI field display a sharp ESR driven by RDI
induced intrinsic field. In contrast, in the SDW state the longitudinal
projection of spin dominates, whereas the transverse components are suppressed.
This prediction indicates a simple way for experimental diagnostic of the SDW
in a quantum wire.",1411.4084v2
2018-08-28,An Intrinsic Spin Orbit Torque Nano-Oscillator,"Spin torque and spin Hall effect nanooscillators generate high intensity spin
wave auto oscillations on the nanoscale enabling novel microwave applications
in spintronics, magnonics, and neuromorphic computing. For their operation,
these devices require externally generated spin currents either from an
additional ferromagnetic layer or a material with a high spin Hall angle. Here
we demonstrate highly coherent field and current tunable microwave signals from
nanoconstrictions in single 15 and 20 nm thick permalloy layers. Using a
combination of spin torque ferromagnetic resonance measurements, scanning
microBrillouin light scattering microscopy, and micromagnetic simulations, we
identify the autooscillations as emanating from a localized edge mode of the
nanoconstriction driven by spin orbit torques. Our results pave the way for
greatly simplified designs of auto oscillating nanomagnetic systems only
requiring a single ferromagnetic layer.",1808.09330v1
2020-08-24,Enhancement of Spin-charge Conversion in Dilute Magnetic Alloys by Kondo Screening,"We derive a kinetic theory capable of dealing both with large spin-orbit
coupling and Kondo screening in dilute magnetic alloys. We obtain the collision
integral non-perturbatively and uncover a contribution proportional to the
momentum derivative of the impurity scattering S-matrix. The latter yields an
important correction to the spin diffusion and spin-charge conversion
coefficients, and fully captures the so-called side-jump process without
resorting to the Born approximation (which fails for resonant scattering), or
to otherwise heuristic derivations. We apply our kinetic theory to a quantum
impurity model with strong spin-orbit, which captures the most important
features of Kondo-screened Cerium impurities in alloys such as
La$_{1-x}$Cu$_6$. We find 1) a large zero-temperature spin Hall conductivity
that depends solely on the Fermi wave number and 2) a transverse spin diffusion
mechanism that modifies the standard Fick's diffusion law. Our predictions can
be readily verified by standard spin-transport measurements in metal alloys
with Kondo impurities.",2008.10185v2
2021-08-30,Entanglement Limits in Hybrid Spin-Mechanical Systems,"We investigate how to generate continuous-variable entanglement between
distant optomechanical and spin systems, by transferring input two-mode
squeezed vacuum state to the system. Such a setup has been proposed for
backaction evading gravitational-wave measurement, squeezing the output noise
below the standard quantum limit. We find that the spin cavity entanglement
saturates to a particular value when no mechanics are involved even though the
entanglement of the input beam increases steadily, and drops down when the
mechanical oscillator interacts with the cavity. Our study also reveals that
the spin optical readout rate enables the robustness of the spin-cavity
entanglement with input squeezing whereas the optomechanical coupling strength
disables it. The entanglement reaches its maximum when the effective resonance
frequency and bandwidth of the cavity match the spin system. Determining
collective quadrature fluctuations, our analysis also shows that even though
the entanglement between spin and cavity, and cavity and mechanics is
significantly present; it is still impossible to obtain entanglement between
spin and mechanical oscillator.",2108.13216v1
2020-12-11,Compositional effect on auto-oscillation behavior of Ni100-xFex/Pt spin Hall nano-oscillators,"We demonstrate the compositional effect on the magnetodynamic and
auto-oscillations properties of Ni100-xFex/Pt (x= 10 to 40) nanoconstriction
based spin Hall nano-oscillators. Using spin-torque ferromagnetic resonance
(ST-FMR) performed on microstrips, we measure a significant reduction in both
damping and spin Hall efficiency with increasing Fe content, which lowers the
spin pumping contribution. The strong compositional effect on spin Hall
efficiency is primarily attributed to the increased saturation magnetization in
Fe-rich devices. As a direct consequence, higher current densities are required
to drive spin-wave auto-oscillations at higher microwave frequencies in Fe-rich
nano-constriction devices. Our results establish the critical role of the
compositional effect in engineering the magnetodynamic and auto-oscillation
properties of spin Hall devices for microwav eand magnonic applications.",2012.06121v2
2021-07-19,Dimensional reduction by geometrical frustration in a cubic antiferromagnet composed of tetrahedral clusters,"Dimensionality is a critical factor in determining the properties of solids
and is an apparent built-in character of the crystal structure. However, it can
be an emergent and tunable property in geometrically frustrated spin systems.
Here, we study the spin dynamics of the tetrahedral cluster antiferromagnet,
pharmacosiderite, via muon spin resonance and neutron scattering. We find that
the spin correlation exhibits a two-dimensional characteristic despite the
isotropic connectivity of tetrahedral clusters made of spin 5/2 Fe3+ ions in
the three-dimensional cubic crystal, which we ascribe to two-dimensionalisation
by geometrical frustration based on spin wave calculations. Moreover, we
suggest that even one-dimensionalisation occurs in the decoupled layers,
generating low-energy and one-dimensional excitation modes, causing large spin
fluctuation in the classical spin system. Pharmacosiderite facilitates studying
the emergence of low-dimensionality and manipulating anisotropic responses
arising from the dimensionality using an external magnetic field.",2107.08735v1
2023-02-04,"Calculating spin-lattice interactions in ferro- and antiferromagnets: the role of symmetry, dimension and frustration","Recently, the interplay between spin and lattice degrees of freedom has
gained a lot of attention due to its importance for various fundamental
phenomena as well as for spintronic and magnonic applications. Examples are
ultrafast angular momentum transfer between the spin and lattice subsystems
during ultrafast demagnetization, frustration driven by structural distortions
in transition metal oxides, or in acoustically driven spin-wave resonances. In
this work, we provide a systematic analysis of spin-lattice interactions for
ferro- and antiferromagnetic materials and focus on the role of lattice
symmetries and dimensions, magnetic order, and the relevance of spin-lattice
interactions for angular momentum transfer as well as magnetic frustration. For
this purpose, we use a recently developed scheme which allows an efficient
calculation of spin-lattice interaction tensors from first principles. In
addition to that, we provide a more accurate and self consistent scheme to
calculate ab initio spin lattice interactions by using embedded clusters which
allows to benchmark the performance of the scheme introduced previously.",2302.02066v2
2023-05-07,Lectures on spintronics and magnonincs,"In this series of lectures, we discuss the basic theoretical concepts of
magnonics and spintronics. We first briefly recall the relevant topics from
quantum mechanics, electrodynamics of continuous media, and basic theory of
magnetism. We then discuss the classical theory of magnetic dynamics:
ferromagnetic and antiferromagnetic resonance, dynamic susceptibilities, and
spin waves. We open the main discussion with phenomena of spin and exchange
spin currents, spin torques, the spin Hall effect, and the spin Hall and Hanle
magnetoresistance. Special emphasis is given to the effects of spin transfer
torque and spin pumping, where we follow the celebrated derivation utilizing
Landauer quantum multi-channel scattering matrix approach. Finally, we outline
the most important features distinguishing antiferromagnetic dynamics from
ferromagnetic one, which make antiferromagnets particularly promising material
candidates for spintronics and magnonics.",2305.04385v1
2006-10-18,Frustrated impurity spins in ordered two-dimensional quantum antiferromagnets,"Dynamical properties of an impurity spin coupled symmetrically to sublattices
of ordered 2D Heisenberg quantum antiferromagnet (i.e., frustrated impurity
spin) are discussed at $T\ge0$ (existence of a small interaction stabilizing
the long range order at $T\ne0$ is implied). We continue our study on this
subject started in Phys.Rev.B 72, 174419 (2005), where spin-1/2 defect is
discussed and the host spins fluctuations are considered within the spin-wave
approximation (SWA). In the present paper we i) go beyond SWA and ii) study
impurities with spins $S\ge1/2$. It is demonstrated that in contrast to defects
coupled to sublattices asymmetrically longitudinal host spins fluctuations play
important role in the frustrated impurity dynamics. The spectral function, that
is proportional to $\omega^2$ within SWA, acquires new terms proportional to
$\omega^2$ and $\omega T^2$. It is observed that the spin-1/2 impurity
susceptibility has the same structure as that obtained within SWA: the Lorenz
peak and the non-resonant term. The difference is that the width of the peak
becomes larger being proportional to $f^2(T/J)^3$ rather than $f^4(T/J)^3$,
where $f$ is the dimensionless coupling parameter. We show that transverse
static susceptibility acquires a new negative logarithmic contribution. In
accordance with previous works we find that host spins fluctuations lead to an
effective one-ion anisotropy on the impurity site. Then defects with $S>1/2$
appears to be split. We observe strong reduction of the value of the splitting
due to longitudinal host spins fluctuations. We demonstrate that the dynamical
impurity susceptibility contains $2S$ Lorenz peaks corresponding to transitions
between the levels, and the non-resonant term.",0610506v1
2022-04-07,Momentum domain polarization probing of forward and inverse spin Hall effect of leaky modes in plasmonic crystals,"Simultaneous manifestation of both forward and inverse photonic Spin Hall
effect in geometrically tailored anisotropic waveguided plasmonic crystal
system is observed through the excitation of the leaky hybridized quasiguided
modes. The quasiguided modes of the plasmonic crystal manifested in the
far-field momentum (Fourier) domain as circular ring-like intensity
distributions, and the different spin orbit interaction (SOI) effects revealed
their exclusive signature as polarization-dependent azimuthal intensity lobes
on top of it. Using a darkfield Fourier domain polarization Mueller matrix
platform, we have observed input spin (circular polarization)- dependent
trajectory of the leaky quasiguided modes in the momentum domain (forward spin
Hall effect) and its reciprocal effect as the wave vector-controlled spin
selection of quasiguided modes (inverse spin Hall effect). These effects are
separately manifested in characteristic Mueller matrix elements enabling their
interpretation as geometrical circular anisotropy effects. Resonance-enabled
enhancement and control of these effects are also demonstrated by exploiting
the spectral Fano-type resonance. The far-field manifestation of
spin-directional excitation of leaky quasiguided modes, their unique
interpretation through momentum domain Mueller matrix, regulation and control
of the SOI effects in plasmonic-photonic crystal systems, opens up exciting
avenues in spin-orbit photonic research.",2204.03699v3
2024-04-09,Collisions of Spin-polarized YO Molecules for Single Partial Waves,"Efficient sub-Doppler laser cooling and optical trapping of YO molecules
offer new opportunities to study collisional dynamics in the quantum regime.
Confined in a crossed optical dipole trap, we achieve the highest phase-space
density of $2.5 \times 10^{-5}$ for a bulk laser-cooled molecular sample. This
sets the stage to study YO-YO collisions in the microkelvin temperature regime,
and reveal state-dependent, single-partial-wave two-body collisional loss
rates. We determine the partial-wave contributions to specific rotational
states (first excited $N=1$ and ground $N=0$) following two strategies. First,
we measure the change of the collision rate in a spin mixture of $N=1$ by
tuning the kinetic energy with respect to the p- and d-wave centrifugal
barriers. Second, we compare loss rates between a spin mixture and a
spin-polarized state in $N=0$. Using quantum defect theory with a partially
absorbing boundary condition at short range, we show that the dependence on
temperature for $N=1$ can be reproduced in the presence of a d-wave or f-wave
resonance, and the dependence on a spin mixture for $N=0$ with a p-wave
resonance.",2404.06652v1
2004-12-15,Spin-orbit interaction of photons and fine splitting of levels in ring dielectric resonator,"We consider eigenmodes of a ring resonator made of a circular dielectric
waveguide. Taking into account the polarization corrections, which are
responsible for the interaction of polarization and orbital properties of
electromagnetic waves (spin-orbit interaction of photons), results in fine
splitting of the levels of scalar approximation. The basic features of this
fine structure of the levels are similar to that of electron levels in an atom.
Namely: 1) sublevels of the fine structure are defined by an additional quantum
number: product of helicity of the wave and its orbital moment; 2) for a
waveguide with a parabolic profile of the refractive index each level of the
scalar approximation splits into N sublevels (N is the principal quantum
number), while for any other profile it splits into 2 sublevels; 3) each level
of the fine structure remains twice degenerated due to local axial symmetry of
the waveguide. Numerical estimations show that the described fine splitting of
levels may be observed in optic-fiber ring resonators.",0412084v3
2011-02-09,Enhancement of the response of non-uniform resonance modes of a nanostructure in the Picoprobe microwave-current injection ferromagnetic resonance,"The non-uniform standing spin-wave modes in thin magnetic films and
nanostructures provide important information about surfaces and buried
interfaces. Very often they are lacking in the recorded ferromagnetic resonance
spectra for symmetry reasons. In this work we experimentally demonstrate that
by direct injection of microwave currents into an array of Permalloy
nanostripes using a microscopic microwave coaxial to coplanar adaptor one can
efficiently excite non-uniform standing spin wave modes with odd symmetry. The
proposed method is quick and allows easy spatial mapping of magnetic properties
with the resolution down to 100 microns. We have validated this method using an
example from a periodical array of nanostripes. The results from direct current
injection are compared to that of microstrip-based FMR measurements.",1102.1805v2
2012-07-20,Measurement of the dynamical dipolar coupling in a pair of magnetic nano-disks using a Ferromagnetic Resonance Force Microscope,"We perform an extensive experimental spectroscopic study of the collective
spin-wave dynamics occurring in a pair of magnetic nano-disks coupled by the
magneto-dipolar interaction. For this, we take advantage of the stray field
gradient produced by the magnetic tip of a ferromagnetic resonance force
microscope (f-MRFM) to continuously tune and detune the relative resonance
frequencies between two adjacent nano-objects. This reveals the anti-crossing
and hybridization of the spin-wave modes in the pair of disks. At the exact
tuning, the measured frequency splitting between the binding and anti-binding
modes precisely corresponds to the strength of the dynamical dipolar coupling
$\Omega$. This accurate f-MRFM determination of $\Omega$ is measured as a
function of the separation between the nano-disks. It agrees quantitatively
with calculations of the expected dynamical magneto-dipolar interaction in our
sample.",1207.4919v1
2013-11-22,"Spin-Wave Resonance Model of Surface Pinning in Ferromagnetic Semiconductor (Ga,Mn)As Thin Films","The source of spin-wave resonance (SWR) in thin films of the ferromagnetic
semiconductor (Ga,Mn)As is still under debate: does SWR stem from the
\emph{surface} anisotropy (in which case the surface inhomogeneity (SI) model
would apply), or does it originate in the \emph{bulk} inhomogeneity of the
magnetic structure of the sample (and thus requires the use of the volume
inhomogeneity (VI) model)? This paper outlines the ground on which the
controversy arose and shows why in different conditions a resonance sample may
meet the assumptions of either the SI or the VI model. In our considerations we
refer to the SWR spectra measured by Furdyna's team [X. Liu \textit{et al.},
Physical Review B \textbf{75}, 195220 (2007)] in (Ga,Mn)As thin films in
different configurations of the static magnetic field $\vec{H}$ with respect to
the surface. We demonstrate that the observed configuration dependence of the
SWR spectrum of the studied material can be described with the use of the
surface pinning parameter.",1311.5767v2
2018-06-12,Resonant spin wave excitation in magnetoplasmonic bilayers by short laser pulses,"In magnetically ordered solids a static magnetic field can be generated by
virtue of the transverse magneto-optical Kerr effect (TMOKE). Moreover, the
latter was shown to be dramatically enhanced due to the optical excitation of
surface plasmons in nanostructures with relatively small optical losses. In
this paper we suggest a new method of resonant optical excitations in a
prototypical bilayer composed of noble metal (Au) with grating and a
ferromagnet thin film of yttrium iron garnet (YIG) via frequency comb. Based on
magnetization dynamics simulations we show that for the frequency comb with the
parameters, chosen in resonant with spin-wave excitations of YIG, TMOKE is
drastically enhanced, hinting towards possible technological applications in
the optical control of spintronics systems.",1806.04764v1
2023-03-03,Spin-wave Resonance in Arrays of Nanoscale Synthetic-antiferromagnets,"The study concerns dynamics of standing spin waves in arrays of sub-100 nm
elliptic synthetic-antiferromagnet (SAF) nanodisks. We performed a detailed
ferromagnetic resonance analysis in conjunction with micromagnetic modeling to
find out several prominent traits of such systems. One broad line is shown to
be the sole resonant response for a SAF of the considered sizes. We demonstrate
that this mode is degenerated, and its excitation map resembles a superposition
of in-center and edge-type oscillations. We also show how this hybrid
excitation leads to almost twofold enhancement in the shape-induced anisotropy
of the mode.",2303.01919v1
2003-11-05,Local shear waves attenuation measurements by the MR methods,"The essential feature of the method is the employment of Elasto-Magnetic
Resonance Spectroscopy (EMRS) for precise local measurements of the attenuation
of shear elastic waves introduced into a biological sample. Such a measurement
can be accomplished by combining the EMRS method with such methods, in which
collective dislocations of spins are induced by external physical factors, such
as variable electric field, strong magnetic field gradient or longitudinal
elastic wave. Theoretical bases of the method presented, related with the
external factors, are discussed in the present paper.",0311022v2
2011-01-04,Quantum storage via refractive index control,"Off-resonant Raman interaction of a single-photon wave packet and a classical
control field in an atomic medium with controlled refractive index is
investigated. It is shown that a continuous change of refractive index during
the interaction leads to the mapping of a single photon state to a
superposition of atomic collective excitations (spin waves) with different wave
vectors and visa versa. The suitability of refractive index control for
developing multichannel quantum memories is discussed and possible schemes of
implementation are considered.",1101.0658v1
2012-02-18,Measuring spectrum of spin wave using vortex dynamics,"We propose to measure the spectrum of magnetic excitation in magnetic
materials using motion of vortex lattice driven by both ac and dc current in
superconductors. When the motion of vortex lattice is resonant with oscillation
of magnetic moments, the voltage decreases at a given current. From transport
measurement, one can obtain frequency of the magnetic excitation with the wave
number determined by vortex lattice constant. By changing the lattice constant
through applied magnetic fields, one can obtains the spectrum of the magnetic
excitation up to a wave vector of order $10\rm{\ nm^{-1}}$.",1202.4048v1
2016-02-19,Nonlinear waves in coherently coupled Bose-Einstein condensates,"We consider a quasi-one-dimensional two-component Bose-Einstein condensate
subject to a coherent coupling between its components, such as realized in
spin-orbit coupled condensates. We study how nonlinearity modifies the dynamics
of the elementary excitations. The spectrum has two branches which are affected
in different ways. The upper branch experiences a modulational instability
which is stabilized by a long wave-short wave resonance with the lower branch.
The lower branch is stable. In the limit of weak nonlinearity and small
dispersion it is described by a Korteweg-de Vries equation or by the Gardner
equation, depending on the value of the parameters of the system.",1602.06141v1
2013-10-09,Electron doping evolution of the magnetic excitations in BaFe2-xNixAs2,"We use inelastic neutron scattering (INS) spectroscopy to study the magnetic
excitations spectra throughout the Brioullion zone in electron-doped iron
pnictide superconductors BaFe$_{2-x}$Ni$_{x}$As$_{2}$ with $x=0.096,0.15,0.18$.
While the $x=0.096$ sample is near optimal superconductivity with $T_c=20$ K
and has coexisting static incommensurate magnetic order, the $x=0.15,0.18$
samples are electron-overdoped with reduced $T_c$ of 14 K and 8 K,
respectively, and have no static antiferromagnetic (AF) order. In previous INS
work on undoped ($x=0$) and electron optimally doped ($x=0.1$) samples, the
effect of electron-doping was found to modify spin waves in the parent compound
BaFe$_2$As$_2$ below $\sim$100 meV and induce a neutron spin resonance at the
commensurate AF ordering wave vector that couples with superconductivity. While
the new data collected on the $x=0.096$ sample confirms the overall features of
the earlier work, our careful temperature dependent study of the resonance
reveals that the resonance suddenly changes its $Q$-width below $T_c$ similar
to that of the optimally hole-doped iron pnictides
Ba$_{0.67}$K$_{0.33}$Fe$_2$As$_2$. In addition, we establish the dispersion of
the resonance and find it to change from commensurate to transversely
incommensurate with increasing energy. Upon further electron-doping to
overdoped iron pnictides with $x=0.15$ and 0.18, the resonance becomes weaker
and transversely incommensurate at all energies, while spin excitations above
$\sim$100 meV are still not much affected. Our absolute spin excitation
intensity measurements throughout the Brillouin zone for $x=0.096,0.15,0.18$
confirm the notion that the low-energy spin excitation coupling with itinerant
electron is important for superconductivity in these materials, even though the
high-energy spin excitations are weakly doping dependent.",1310.2333v1
2011-12-07,Spin Pumping Driven by Bistable Exchange Spin Waves,"Spin pumping driven by bistable exchange spin waves is demonstrated in a
Pt/Y$_3$Fe$_5$O$_{12}$ film under parametric excitation. In the
Pt/Y$_3$Fe$_5$O$_{12}$ film, the spin pumping driven by parametric excitation
selectively enhances the relaxation of short-wavelength exchange spin waves,
indicating strong coupling between the exchange spin waves and spin currents at
the interface through efficient spin transfer. The parametric spin pumping,
furthermore, allows direct access to nonlinear spin wave dynamics in
combination with the inverse spin Hall effect, revealing unconventional
bistability of the exchange spin waves.",1112.1596v2
2000-02-25,Mechanical detection of nuclear spin relaxation in a micron-size crystal,"A room temperature nuclear magnetic resonance force microscope (MRFM), fitted
in a $^1$Tesla electromagnet, is used to measure the nuclear spin relaxation of
$^1$H in a micron-size (70ng) crystal of ammonium sulfate. NMR sequences,
combining both pulsed and continuous wave r.f. fields, have allowed us to
measure mechanically $T_2$ and $T_1$, the transverse and longitudinal spin
relaxation times. Because two spin species with different $T_1$ values are
measured in our $7\mu{\rm m}$ thick crystal, magnetic resonance imaging of
their spatial distribution inside the sample section are performed. To
understand quantitatively the measured signal, we carefully study the influence
of the spin-lattice relaxation and the non-adiabaticity of the c.w. sequence on
the intensity and time dependence of the detected signal.",0002404v1
2008-03-19,Resonant Spin-Transfer-Driven Switching of Magnetic Devices Assisted by Microwave Current Pulses,"The torque generated by the transfer of spin angular momentum from a
spin-polarized current to a nanoscale ferromagnet can switch the orientation of
the nanomagnet much more efficiently than a current-generated magnetic field,
and is therefore in development for use in next-generation magnetic random
access memory (MRAM). Up to now, only DC currents and square-wave current
pulses have been investigated in spin-torque switching experiments. Here we
present measurements showing that spin transfer from a microwave-frequency
pulse can produce a resonant excitation of a nanomagnet and lead to improved
switching characteristics in combination with a square current pulse. With the
assistance of a microwave-frequency pulse, the switching time is reduced and
achieves a narrower distribution than when driven by a square current pulse
alone, and this can permit significant reductions in the integrated power
required for switching. Resonantly excited switching may also enable
alternative, more compact MRAM circuit architectures.",0803.2880v1
2010-10-21,Controlling spin motion and interactions in a one-dimensional Bose gas,"Experiments on ultracold gases offer unparalleled opportunities to explore
quantum many-body physics, with excellent control over key parameters including
temperature, density, interactions and even dimensionality. In some systems,
atomic interactions can be adjusted by means of magnetic Feshbach resonances,
which have played a crucial role in realizing new many-body phenomena. However,
suitable Feshbach resonances are not always available, and they offer limited
freedom since the magnetic field strength is the only control parameter. Here
we show a new way to tune interactions in one-dimensional quantum gases using
state-dependent dressed potentials, enabling control over non-equilibrium spin
motion in a two-component gas of 87Rb. The accessible range includes the point
of spin-independent interactions where exact quantum many-body solutions are
available and the point where spin motion is frozen. This versatility opens a
new route to experiments on spin waves, spin-""charge"" separation and the
relation between superfluidity and magnetism in low-dimensional quantum gases.",1010.4545v1
2015-02-20,Oscillating spin-orbit interaction in two-dimensional superlattices: sharp transmission resonances and time-dependent spin polarized currents,"We consider ballistic transport through a lateral, two-dimensional
superlattice with experimentally realizable, sinusoidally oscillating
Rashba-type spin-orbit interaction. The periodic structure of the rectangular
lattice produces a spin-dependent miniband structure for static SOI. Using
Floquet theory, transmission peaks are shown to appear in the mini-bandgaps as
a consequence of the additional, time-dependent SOI. A detailed analysis shows
that this effect is due to the generation of harmonics of the driving
frequency, via which e.g., resonances that cannot be excited in the case of
static SOI become available. Additionally, the transmitted current shows space
and time-dependent partial spin-polarization, in other words, polarization
waves propagate through the superlattice.",1502.05798v1
2015-12-04,Kondo screening in two-dimensional $p$-type transition-metal dichalcogenides,"Systems with strong spin orbit coupling support a number of new phases of
matter and novel phenomena. This work focuses on the interplay of spin orbit
coupling and interactions in yielding correlated phenomena in two dimensional
transition metal dichalcogenides. In particular we explore the physics of Kondo
screening resulting from the lack of centro-symmetry, large spin splitting and
spin valley locking in hole doped systems. The key ingredients are i) valley
dependent spin-momentum locking perpendicular to the two dimensional crystal;
ii) single nondegenerate Fermi surface per valley, and iii) nontrivial Berry
curvature associated with the low energy bands. The resulting Kondo resonance
has a finite triplet component and nontrivial momentum space structure which
facilitates new approaches to both probe and manipulate the correlated state.
Using a variational wave function and the numerical renormalization group
approaches we study the nature of the Kondo resonance both in the absence and
presence of circularly polarized light. The latter induces an imbalance in the
population of the two valleys leading to novel magnetic phenomena in the
correlated state.",1512.01590v2
2020-04-28,Enhancement of acoustic spin pumping by acoustic distributed Bragg reflector cavity,"Surface acoustic waves (SAWs) in the GHz frequency range can inject spin
currents dynamically into adjacent nonmagnetic layers via spin pumping effect
associated with ferromagnetic resonance. Here, we demonstrate an enhancement of
acoustic ferromagnetic resonance and spin current generation by a pair of SAW
reflector gratings, which form an acoustic analogue of the distributed Bragg
reflector cavity. In the experiment, we confirmed 2.04 $\pm$ 0.02 times larger
SAW power absorption in a device with cavity than in case of no acoustic
cavity. We confirmed up to 2.96 $\pm$ 0.02 times larger spin current generation
by measuring electric voltages generated by the inverse Edelstein effect (IEE)
at the interface between Cu and Bi$_2$O$_3$. The results suggest that acoustic
cavities would be useful to enhance the conversion efficiency in SAW driven
coupled magnon-phonon dynamics.",2004.13885v3
2020-08-25,Electron Spin Resonance of Defects in Spin Chains. o-(DMTTF)2X : a versatile system behaving like molecular magnet,"The paper presents the Electron Paramagnetic Resonance study of defects in
the spin chain o- (DMTTF)2X family using continuous wave and pulsed techniques.
The defects in spin chains are strongly correlated and present similar
microscopic structure as a molecular magnet. By means of 2D-HYSCORE and DFT
calculations we show a strong reduction of hyperfine coupling between the
defects and the nuclear spin bath. We assume that the reduction is due to the
Heisenberg exchange interaction which screens the effect of the nuclei.",2008.10897v1
2020-09-27,Dynamical spin susceptibility in La2CuO4 studied by resonant inelastic x-ray scattering,"Resonant inelastic X-ray scattering (RIXS) is a powerful probe of elementary
excitations in solids. It is now widely applied to study magnetic excitations.
However, its complex cross-section means that RIXS has been more difficult to
interpret than inelastic neutron scattering (INS). Here we report
high-resolution RIXS measurements of magnetic excitations of La2CuO4, the
antiferromagnetic parent of one system of high-temperature superconductors. At
high energies (~2 eV), the RIXS spectra show angular-dependent dd orbital
excitations which are found to be in good agreement with single-site multiplet
calculations. At lower energies (<0.3 eV), we show that the
wavevector-dependent RIXS intensities are proportional to the product of the
single-ion spin-flip cross section and the dynamical susceptibility of the
spin-wave excitations. When the spin-flip crosssection is dividing out, the
RIXS magnon intensities show a remarkable resemblance to INS data. Our results
show that RIXS is a quantitative probe the dynamical spin susceptibility in
cuprate and therefore should be used for quantitative investigation of other
correlated electron materials.",2009.12925v1
2022-04-27,Refining magnetic interactions from the magnetic field dependence of spin-wave excitations in magnetoelectric LiFePO$_4$,"We investigated the spin excitations of magnetoelectric $\text{LiFePO}_4$ by
THz absorption spectroscopy in magnetic fields up to 33$\,$T. By studying their
selection rules, we found not only magnetic-dipole, but also electric-dipole
active (electromagnons) and magnetoelectric resonances. The magnetic field
dependence of four strong low-energy modes is reproduced well by our
four-sublattice spin model for fields applied along the three orthorhombic
axes. From the fit, we refined the exchange couplings, single-ion anisotropies,
and the Dzyaloshinskii-Moriya interaction parameters. Additional spin
excitations not described by the mean-field model are observed at higher
frequencies. Some of them shows a strong shift with magnetic field, up to
4$\,\text{cm}^{-1}/\text{T}$, when the field is applied along the easy axis.
Based on this field dependence, we attribute these high frequency resonances to
excitation of higher spin multipoles and of two magnons, which become
THz-active due to the low symmetry of the magnetically ordered state.",2204.12967v1
2008-12-17,Variational RVB wave function for the spin-1/2 Heisenberg Model on honeycomb lattice,"In this work, a long-range resonating valence bond state is proposed as a
variational wave function for the ground state of the $S=1/2$ antiferromagnetic
Heisenberg model on the honeycomb lattice. Employing Variational Monte Carlo
(VMC) method, we show that the ground state energy obtained from such RVB wave
function, lies well below the energy of the N\'eel state and compares very well
to the energies evaluated from spin-wave theory and series expansion method. We
also obtain the spin-spin correlation function along zig-zag and armchair
directions and find that the two correlations are different, which indicates
the anisotropic nature of the system. We compare our results with the square
lattice and we show that although the quantum fluctuations on honeycomb lattice
are much stronger, but do not completely destroy the magnetic order.",0812.3229v1
2012-01-02,Localized domain-wall excitations in patterned magnetic dots probed by broadband ferromagnetic resonance,"We investigate the magnetization dynamics in circular Permalloy dots with
spatially separated magnetic vortices interconnected by domain walls (double
vortex state). We identify a novel type of quasi one-dimensional (1D) localised
spin wave modes confined along domain walls, connecting each of two vortex
cores with two edge half-antivortices. Variation of the mode eigenfrequencies
with the dot size is in quantitative agreement with the developed model, which
considers a dipolar origin of the localized 1D spin waves or so-called
Winter\'s magnons [J.M. Winter, Phys.Rev. 124, 452 (1961)]. These spin waves
are analogous to the displacement waves of strings, and could be excited in a
wide class of patterned magnetic nanostructures possessing domain walls, namely
in triangular, square, circular or elliptic magnetic dots.",1201.0482v1
2012-06-07,"Hybridization of electromagnetic, spin and acoustic waves in magnetic having conical spiral ferromagnetic order","The spectrum of hybrid electromagnetic-spin-acoustic waves for magnetic
having conical spiral ferromagnetic structure defined by heterogeneous exchange
and relativistic interactions have been received. The possibility of resonant
interaction of spin, electromagnetic and acoustic waves has been shown. The
electromagnetic waves reflectance from the half-infinity layer of magnetic
having conical spiral ferromagnetic order has been calculated for different
values of external magnetic field (angle of spiral). The acoustic Faradey
effect has been considered.",1206.1421v2
2021-11-26,A modal approach to modelling spin wave scattering,"Efficient numerical methods are required for the design of optimised devices.
In magnonics, the primary computational tool is micromagnetic simulations,
which solve the Landau-Lifshitz equation discretised in time and space.
However, their computational cost is high, and the complexity of their output
hinders insight into the physics of the simulated system, especially in the
case of multimode propagating wave-based devices. We propose a finite-element
modal method allowing an efficient solution of the scattering problem for
dipole-exchange spin waves propagating perpendicularly to the magnetisation
direction. The method gives direct access to the scattering matrix of the whole
system and its components. We extend the formula for the power carried by a
magnetostatic mode in the Damon-Eshbach configuration to the case with
exchange, allowing the scattering coefficients to be normalised to represent
the fraction of the input power transferred to each output channel. We apply
the method to the analysis of spin-wave scattering on a basic functional block
of magnonic circuits, consisting of a resonator dynamically coupled to a thin
film. The results and the method are validated by comparison with micromagnetic
simulations.",2111.13448v2
2012-02-13,Crossover from inelastic magnetic scattering of Cooper pairs to spin-wave dispersion produces low-energy kink in cuprates,"We present GW based self-energy calculations for the state of coexisting
spin-density wave and d-wave superconductivity in a series of cuprate
superconductors. In these systems, the spin resonance spectrum exhibits the
typical `hour-glass' form, whose upward and downward dispersion branches come
from the gapped spin-wave and magnetic scattering of Cooper pairs,
respectively. We show that the crossover between these two different dispersion
features leads to an abrupt change in slope in the quasiparticle self-energy,
and hence the low-energy kink commences in the single-particle quasiparticle
spectrum. The calculated electron-bosonic coupling strength agrees well with
experimental data as a function of temperature, doping and material. The
results demonstrate that the electronic correlations dominate the quasiparticle
spectra of cuprates near the low-energy kink, suggesting a relatively smaller
role for phonons in this energy range.",1202.2596v1
2019-02-28,Magnetic structure and spin waves in the frustrated ferro-antiferromagnet Pb$_2$VO(PO$_4$)$_2$,"Single crystal neutron diffraction, inelastic neutron scattering and electron
spin resonance experiments are used to study the magnetic structure and spin
waves in Pb$_2$VO(PO$_4$)$_2$, a prototypical layered $S=1/2$ ferromagnet with
frustrating next nearest neighbor antiferromagnetic interactions. The observed
excitation spectrum is found to be inconsistent with a simple square lattice
model previously proposed for this material. At least four distinct exchange
coupling constants are required to reproduce the measured spin wave dispersion.
The degree of magnetic frustration is correspondingly revised and found to be
substantially smaller than in all previous estimates.",1902.11172v3
2019-07-01,DC spinmotive force from microwave-active resonant dynamics of skyrmion crystal under a tilted magnetic field,"We theoretically show that a temporally oscillating spin-driven electromotive
force or voltage with a large DC component can be generated by exciting
microwave-active spin-wave modes of a skyrmion crystal confined in a quasi
two-dimensional magnet under a tilted magnetic field. The DC component and the
AC amplitude of the oscillating electric voltage is significantly enhanced when
the microwave frequency is tuned to an eigenfrequency of the peculiar spin-wave
modes of the skyrmion crystal called ``rotation modes"" and ``breathing mode"",
whereas the sign of the DC component depends on the microwave polarization and
on the spin-wave mode. These results provide an efficient means to convert
microwaves to a DC electric voltage by using skyrmion-hosting magnets and to
switch the sign of the voltage via tuning the microwave frequency, which are
important capabilities for spintronic devices.",1907.00621v1
2020-01-22,Resonant Precession Modulation Based Magnetic Field Receivers,"Antenna technology provides the crucial interface between electronic devices
and electromagnetic waves required for wireless communications. This technology
has operated under largely the same general principles for over a century,
resulting in stagnation of advancements in modern times and fundamentally
limiting the extent to which potential applications of wireless communications
may be realized. Herein we propose a novel concept for antenna operation
employing the nonlinear precession dynamics of subatomic spins. An
electromagnetic wave incident on a precessing spin will serve to modulate the
spin frequency of precession. Antennas operating based on a detection of these
spin dynamics are then able to fully characterize the incident wave while
achieving substantial amplifications, higher sensitivities, and smaller form
factors as compared to conventional antennas. A preliminary experimental
implementation of the proposed concept establishes its feasibility and is
already able to demonstrate significant amplification and size benefits.",2001.08059v1
2022-01-27,Simultaneous measurement of the exchange parameter and saturation magnetization using propagating spin waves,"The exchange interaction in ferromagnetic ultra-thin films is a critical
parameter in magnetization-based storage and logic devices, yet the accurate
measurement of it remains a challenge. While a variety of approaches are
currently used to determine the exchange parameter, each has its limitations,
and good agreement among them has not been achieved. To date, neutron
scattering, magnetometry, Brillouin light scattering, spin-torque ferromagnetic
resonance spectroscopy, and Kerr microscopy have all been used to determine the
exchange parameter. Here we present a novel method that exploits the wavevector
selectivity of Brillouin light scattering to measure the spin wave dispersion
in both the backward volume and Damon-Eshbach orientations. The exchange,
saturation magnetization, and magnetic thickness are then determined by a
simultaneous fit of both dispersion branches with general spin wave theory
without any prior knowledge of the thickness of a magnetic ""dead layer"". In
this work, we demonstrate the strength of this technique for ultrathin metallic
films, typical of those commonly used in industrial applications for magnetic
random-access memory.",2201.11270v1
2014-10-24,Non-linear spin-wave excitation at low bias fields,"Non-linear magnetization dynamics is essential for the operation of many
spintronics devices. For microwave assisted switching of magnetic elements the
low field regime is of particular interest. In addition a large number of
experiments uses high amplitude FMR in order to generate d.c. currents via spin
pumping mechanism. Here we use time resolved X-ray magnetic circular dichroism
experiments to determine the number density of excited magnons in magnetically
soft Ni_80Fe_20 thin films at small bias fields and large rf-excitation
amplitudes. Our data shows that the common model of non-linear ferromagnetic
resonance is not suitable to describe the low bias field limit. Here we derive
a new model of parametric spin-wave excitation which correctly predicts
threshold amplitudes and decay rates also at low bias fields. In fact a new
series of critical modes with amplitude phase oscillations is found,
generalizing the theory of parametric spin-wave excitation.",1410.6693v1
2018-01-09,Unidirectional spin density wave state in metallic (Sr1-xLax)2IrO4,"Materials that exhibit both strong spin orbit coupling and electron
correlation effects are predicted to host numerous new electronic states. One
prominent example is the Jeff =1/2 Mott state in Sr2IrO4, where introducing
carriers is predicted to manifest high temperature superconductivity analogous
to the S=1/2 Mott state of La2CuO4. While bulk superconductivity currently
remains elusive, anomalous quasi-particle behaviors paralleling those in the
cuprates such as pseudogap formation and the formation of a d-wave gap are
observed upon electron-doping Sr2IrO4. Here we establish a magnetic parallel
between electron-doped Sr2IrO4 and hole-doped La2CuO4 by unveiling a spin
density wave state in electron-doped Sr2IrO4. Our magnetic resonant x-ray
scattering data reveal the presence of an incommensurate magnetic state
reminiscent of the diagonal spin density wave state observed in the monolayer
cuprate (La1-xSrx)2CuO4. This link supports the conjecture that the quenched
Mott phases in electron-doped Sr2IrO4 and hole-doped La2CuO4 support common
competing electronic phases.",1801.03076v1
2023-01-20,Giant spin-vorticity coupling excited by shear-horizontal surface acoustic waves,"A non-magnetic layer can inject spin-polarized currents into an adjacent
ferromagnetic layer via spin vorticity coupling (SVC), inducing spin wave
resonance (SWR). In this work, we present the theoretical model of SWR
generated by shear-horizontal surface acoustic wave (SH-SAW) via SVC, which
contains distinct vorticities from well-studied Rayleigh SAW. Both Rayleigh-
and SH-SAW delay lines have been designed and fabricated with a Ni81Fe19/Cu
bilayer integrated on ST-cut quartz. Given the same wavelength, the measured
power absorption of SH-SAW is four orders of magnitudes higher than that of the
Rayleigh SAW. In addition, a high-order frequency dependence of the SWR is
observed in the SH-SAW, indicating SVC can be strong enough to compare with
magnetoelastic coupling.",2301.08586v1
1999-04-17,Tunneling Via Individual Electronic States in Ferromagnetic Nanoparticles,"We measure electron tunneling via discrete energy levels in ferromagnetic
cobalt particles less than 4 nm in diameter, using non-magnetic electrodes. Due
to magnetic anisotropy, the energy of each tunneling resonance shifts as an
applied magnetic field rotates the particle's magnetic moment. We see both
spin-increasing and decreasing tunneling transitions, but we do not observe the
spin degeneracy at small magnetic fields seen previously in non-magnetic
materials. The tunneling spectrum is denser than predicted for independent
electrons, possibly due to spin-wave excitations.",9904248v2
2000-12-19,Significance of the direct relaxation process in the low-energy spin dynamics of a one-dimensional ferrimagnet NiCu(C_7H_6N_2O_6)(H_2O)_3 2H_2O,"In response to recent nuclear-magnetic-resonance measurements on a
ferrimagnetic chain compound NiCu(C_7H_6N_2O_6)(H_2O)_3 2H_2O [Solid State
Commun. {\bf 113} (2000) 433], we calculate the nuclear spin-lattice relaxation
rate 1/T_1 in terms of a modified spin-wave theory. Emphasizing that the
dominant relaxation mechanism arises from the direct (single-magnon) process
rather than the Raman (two-magnon) one, we explain the observed temperature and
applied-field dependences of 1/T_1. Ferrimagnetic relaxation phenomena are
generally discussed and novel ferrimagnets with extremely slow dynamics are
predicted.",0012342v1
2008-12-11,Effect of a strong laser on spin precession,"The semiclassical dynamics of a charged spin-1/2 particle in an intense
electromagnetic plane wave is analyzed beyond the electric dipole approximation
and taking into account the leading relativistic corrections to the Pauli
equation. It is argued that the adiabatic spin evolution driven by a low
intensity radiation changes its character drastically as an intensity of a
laser is increasing. Particularly, it is shown that a charged particle exposes
a spin flip resonance at a certain pick value of a laser field strength, which
is determined by a particle's gyromagnetic ratio.",0812.2110v1
2009-01-08,Ultralong trapping of light using double spin coherence gratings,"Ultralong trapping of light has been observed in an optically dense
three-level solid medium interacting with a pair of counterpropagating coupling
fields. Unlike the light trapping based on standing-wave gratings excited by
the same frequency pair of counterpropagating light fields (M. Bajcsy et al.,
Nature 426, 638 (2003)), the present method uses resonant Raman optical
field-excited spin coherence gratings. The observed light trapping time is two
orders of magnitude longer than the expected value of the spin dephasing time,
where the extended storage time has potential for quantum information
processing based on nonlinear optics.",0901.1082v2
2009-05-28,Enhanced spin Hall effect in semiconductor heterostructures with artificial potential,"We theoretically investigate an extrinsic spin Hall effect (SHE) in
semiconductor heterostructures due to the scattering by an artificial potential
created by antidot, STM tip, etc. The potential is electrically tunable. First,
we formulate the SHE in terms of phase shifts in the partial wave expansion for
two-dimensional electron gas. The effect is significantly enhanced by the
resonant scattering when the attractive potential is properly tuned. Second, we
examine a three-terminal device including an antidot, which possibly produces a
spin current with polarization of more than 50%.",0905.4551v1
2009-10-21,Parametric resonance and spin-charge separation in 1D fermionic systems,"We show that the periodic modulation of the Hamiltonian parameters for 1D
correlated fermionic systems can be used to parametrically amplify their
bosonic collective modes. Treating the problem within the Luttinger liquid
picture, we show how charge and spin density waves with different momenta are
simultaneously amplified. We discuss the implementation of our predictions for
cold atoms in 1D modulated optical lattices, showing that the fermionic
momentum distribution directly provides a clear signature of spin-charge
separation.",0910.4123v2
2012-12-12,Results from the spin programme at COSY-ANKE,"Some of the important results from the COSY-Juelich spin programme are
summarised. These include the measurement of the deuteron beam momentum through
the excitation of a depolarising resonance, which allowed the mass of the
eta-meson to be determined to high precision. The charge exchange of polarised
deuterons on hydrogen gave rise to a detailed study of the spin dependence of
large angle neutron-proton elastic scattering amplitudes. The measurements of
the cross section and analysing powers for pion production in both pp and pn
collisions at 353 MeV could be described very successfully in terms of a
partial wave decomposition.",1212.2771v1
2015-05-12,Effect of nuclear spin symmetry in cold and ultracold reactions: D + para/ortho-H$_2$,"We report results for reaction and vibrational quenching of the collision D
with para-H$_2$($v,j=0$) and ortho-H$_2$($v,j=1$) at cold and ultracold
temperatures. We investigate the effect of nuclear spin symmetry for barrier
dominated processes ($0\le v\le 4$) and for one barrierless case ($v=5$). We
find resonant structures for energies in the range corresponding to 0.01--10 K,
which depend on the nuclear spin of H$_2$, arising from contributions of
specific partial waves. We discuss the implications on the results in this
benchmark system for ultracold chemistry.",1505.03172v1
2017-12-27,Finite temperature magnon spectra in yttrium iron garnet from mean field approach in tight-binding model,"We study magnon spectra at finite temperature in yttrium iron garnet from
tight-binding model with nearest neighboring exchange interaction. The spin
reduction due to thermal magnon excitation are taken into account via the mean
field approximation to the local spin and found to be different at two sets of
iron atoms. The resulting temperature dependence of the spin wave gap shows
good agreement with experiment. We find only two magnon modes are relevant to
ferromagnetic resonance.",1712.09512v1
2008-06-21,Spin-resolved impurity resonance states in electron-doped cuprate superconductors,"With the aim at understanding the non-monotonic $d_{x^{2}-y^{2}}$-wave gap,
we analyze the local electronic structure near impurities in the electron-doped
cuprate superconductors. We find that the local density of states near a
non-magnetic impurity in the scenario of $d_{x^{2}-y^{2}}$-wave
superconductivity with higher harmonics is qualitatively different from that
obtained from the $d_{x^{2}-y^{2}}$-wave superconductivity coexisting with
antiferromagnetic spin density wave order. We propose that spin-polarized
scanning tunneling microscopy measurements can distinguish the two scenarios
and shed light on the real physical origin of a non-monotonic
$d_{x^{2}-y^{2}}$-wave gap.",0806.3502v3
2002-12-22,Time Asymmetric Quantum Theory - III. Decaying States and the Causal Poincare Semigroup,"A relativistic resonance which was defined by a pole of the $S$-matrix, or by
a relativistic Breit-Wigner line shape, is represented by a generalized state
vector (ket) which can be obtained by analytic extension of the relativistic
Lippmann-Schwinger kets. These Gamow kets span an irreducible representation
space for Poincar\'e transformations which, similar to the Wigner
representations for stable particles, are characterized by spin (angular
momentum of the partial wave amplitude) and complex mass (position of the
resonance pole). The Poincar\'e transformations of the Gamow kets, as well as
of the Lippmann-Schwinger plane wave scattering states, form only a semigroup
of Poincar\'e transformations into the forward light cone. Their transformation
properties are derived. From these one obtains an unambiguous definition of
resonance mass and width for relativistic resonances. The physical
interpretation of these transformations for the Born probabilities and the
problem of causality in relativistic quantum physics is discussed.",0212282v1
2000-05-31,Multiphoton Resonant Transitions of Electrons in the Laser Field in a Medium,"Within the scope of the relativistic quantum theory for electron-laser
interaction in a medium and using the resonant approximation for the two
degenerated states of an electron in a monochromatic radiation field [1] a
nonperturbative solution of the Dirac equation (nonlinear over field solution
of the Hill type equation) are obtained. The multiphoton cross sections of
electrons coherent scattering on the plane monochromatic wave at the Cherenkov
resonance are obtained taking into account the specificity of induced Cherenkov
process [1, 2] and spin-laser interaction as well. In the result of this
resonant scattering the electron beam quantum modulation at high frequencies
occurs that corresponds to a quantity of an electron energy exchange at the
coherent reflection from the ''phase lattice'' of slowed plane wave in a
medium. So, we can expect to have a coherent X-ray source in induced Cherenkov
process, since such beam is a potential source of coherent radiation itself.",0005130v1
2017-05-08,Helimagnon resonances in an intrinsic chiral magnonic crystal,"We experimentally study magnetic resonances in the helical and conical
magnetic phases of the chiral magnetic insulator Cu$_2$OSeO$_3$ at the
temperature $T$=5 K. Using a broadband microwave spectroscopy technique based
on vector network analysis, we identify three distinct sets of helimagnon
resonances in the frequency range 2 GHz $\leq f \leq$ 20 GHz. The extracted
resonance frequencies are in accordance with calculations of the helimagnon
bandstructure found in an intrinsic chiral magnonic crystal. The periodic
modulation of the equilibrium spin direction that leads to the formation of the
magnonic crystal is a direct consequence of the chiral magnetic ordering caused
by the Dzyaloshinskii-Moriya interaction. The opening of magnon band-gaps
allows for excitation of helimagnons with wave vectors that are multiples of
the spiral wave vector.",1705.02874v2
2020-04-21,Merging Compact Binaries Near a Rotating Supermassive Black Hole: Eccentricity Excitation due to Apsidal Precession Resonance,"We study the dynamics of merging compact binaries near a rotating
supermassive black hole (SMBH) in a hierarchical triple configuration. We
include various general relativistic effects that couple the inner orbit, the
outer orbit and the spin of the SMBH. During the orbital decay due to
gravitational radiation, the inner binary can encounter an ""apsidal precession
resonance"" and experience eccentricity excitation. This resonance occurs when
the apsidal precession rate of the inner binary matches that of the outer
binary, with the precessions driven by both Newtonian interactions and various
post-Newtonian effects. The eccentricity excitation requires the outer orbit to
have a finite eccentricity, and is most effective for triples with small mutual
inclinations, in contrast to the well-studied Lidov-Kozai effect. The resonance
and the associated eccentricity growth may occur while the binary emits
gravitational waves in the low-frequency band, and may be detectable by future
space-based gravitational wave detectors.",2004.10205v3
2022-04-11,"Resonances, black hole mimickers and the greenhouse effect: consequences for gravitational-wave physics","Ultracompact objects with photonspheres are known to mimic many observational
features of black holes. It has been suggested that anomalous tidal heating or
the presence of resonances in gravitational wave signals would be a clear
imprint of a surface or absence of a horizon. Such claims and studies are all
based on a frequency-domain analysis, assuming stationarity. Here we show that
the object needs to first ""fuel-up"" until it reaches the stationary regime. The
presence of a stable light ring and large light-travel times inside the object
may in fact delay enormously the ""charging-up"" and effectively contribute to
the effacement of structure. In other words, black hole mimickers behave as
black holes more efficiently than previously thought. Our results have
implications for other resonant systems with sharp resonances, including
""floating orbits"" around spinning black holes. A proper accounting of the
self-force for such systems seems to be both mandatory, and would have
important applications for tests of horizon physics.",2204.05315v1
1995-03-02,Resonant two-magnon Raman scattering in parent compounds of high-T$_c$ superconductors.,"We propose a theory of two-magnon Raman scattering from the insulating parent
compounds of high-T$_c$ superconductors, which contains information not only on
magnetism, but also on the electronic properties in these materials. We use
spin density wave formalism for the Hubbard model, and study diagrammatically
the profile of the two-magnon scattering and its intensity dependence on the
incoming photon frequency $\omega_i$ both for $\omega_i \ll U$ and in the
resonant regime, in which the energy of the incident photon is close to the gap
between conduction and valence bands. In the nonresonant case, we identify the
diagrams which contribute to the conventional Loudon-Fleury Hamiltonian. In the
resonant regime, where most of the experiments have been done, we find that the
dominant contribution to Raman intensity comes from a different diagram, one
which allows for a simultaneous vanishing of all three of its denominators
(i.e., a triple resonance). We study this diagram in detail and show that the
triple resonance, combined with the spin-density-wave dispersion relation for
the carriers, explains the unusual features found in the two-magnon profile and
in the two-magnon peak intensity dependence on the incoming photon frequency.
In particular, our theory predicts a maximum of the two-magnon peak intensity
right at the upper edge of the features in the optical data, which has been one
of the key experimental puzzles.",9503010v1
2016-07-08,Morphology effects on spin-dependent transport and recombination in polyfluorene thin films,"We have studied the role of spin-dependent processes on conductivity in
polyfluorene (PFO) thin films by conducting continuous wave (c.w.) electrically
detected magnetic resonance (EDMR) spectroscopy at temperatures between 10 K
and 293 K using microwave frequencies between about 100 MHz and 20 GHz as well
as pulsed EDMR at X-band. Variable frequency EDMR allows us to establish the
role of spin-orbit coupling in spin-dependent processes, pulsed EDMR probes
coherent spin motion effects. We used PFO for this study in order to allow for
the investigation of the effects of microscopic morphological ordering since
this material can adopt two distinct intrachain morphologies: an amorphous
(glassy) phase, and an ordered (beta) phase. In thin films of organic
light-emitting diodes (OLEDs) the appearance of a particular phase can be
controlled by deposition parameters, and is verified by electroluminescence
spectroscopy. We conducted multi-frequency c.w. EDMR, electrically detected
Rabi spinbeat experiments, Hahn-echo and inversion-recovery measurements.
Coherent echo spectroscopy reveals electrically detected electron spin-echo
envelope modulation (ESEEM) due to the precession of the carrier spins around
the protons. Our results demonstrate that while conformational disorder can
influence the observed EDMR signals, including the sign of the current changes
on resonance as well as the magnitudes of local hyperfine fields and charge
carrier spin-orbit interactions, it does not qualitatively affect the nature of
spin-dependent transitions in this material. At 293 K and 10 K, polaron-pair
recombination through weakly spin-spin coupled intermediate charge carrier pair
states is dominant, while at low temperatures, additional signatures of
spin-dependent charge transport through the interaction of polarons with
triplet excitons are seen in the half-field resonance of a triplet spin-1
species.",1607.02462v1
2012-08-02,"Observation of a $J^{PC}=1^{-+}$ exotic signal in the $π^{-}π^{0}π^{0}$ system diffractively produced at COMPASS, and comparison to the charged decay mode","The COMPASS experiment at the CERN SPS features good charged particle
tracking and coverage by electromagnetic calorimetry, and our data provide
excellent opportunity for simultaneous observation of new states in two
different decay modes within the same experiment. The existence of the
spin-exotic $\pi_1(1600)$ resonance in the $\rho\pi$ decay channel is studied
for the first time in COMPASS in both decay modes of the diffractively produced
$(3\pi)^{-}$ system: $\pi^{-}p \rightarrow \pi^{-}\pi^{0}\pi^{0}p$ and
$\pi^{-}p \rightarrow \pi^{-}\pi^{+}\pi^{-}p$. A preliminary partial-wave
analysis (PWA) performed on the 2008 proton target data allows for a first
conclusive comparison of both $(3\pi)^{-}$ decay modes not only for main waves
but also for small ones, including the spin-exotic $1^{-+}$ wave. We find the
neutral versus charged mode results in good agreement with expectations from
isospin symmetry. Both, the intensities and the relative phases to well-known
resonances, are consistent for the neutral and the charged decay modes of the
$(3\pi)^{-}$ system. The status on the search for the spin-exotic $\pi_1(1600)$
resonance produced on a proton target is discussed.",1208.0474v1
2022-09-27,Tailoring crosstalk between localized 1D spin-wave nanochannels using focused ion beams,"1D spin-wave conduits are envisioned as nanoscale components of
magnonics-based logic and computing schemes for future generation electronics.
`A-la-carte methods of versatile control of the local magnetization dynamics in
such nanochannels are highly desired for efficient steering of the spin waves
in magnonic devices. Here, we present a study of localized dynamical modes in
1-$\mu$m-wide Permalloy conduits probed by microresonator ferromagnetic
resonance technique. We clearly observe the lowest-energy edge mode in the
microstrip after its edges were finely trimmed by means of focused Ne$^+$ ion
irradiation. Furthermore, after milling the microstrip along its long axis by
focused ion beams, creating consecutively $\sim$50 and $\sim$100 nm gaps,
additional resonances emerge and are attributed to modes localized at the inner
edges of the separated strips. To visualize the mode distribution, spatially
resolved Brillouin light scattering microscopy was used showing an excellent
agreement with the ferromagnetic resonance data and confirming the mode
localization at the outer/inner edges of the strips depending on the magnitude
of the applied magnetic field. Micromagnetic simulations confirm that the
lowest-energy modes are localized within $\sim$15-nm-wide regions at the edges
of the strips and their frequencies can be tuned in a wide range (up to 5 GHz)
by changing the magnetostatic coupling (i.e. spatial separation) between the
microstrips.",2209.13180v2
2007-02-15,The resonance peak in the electron-doped cuprate superconductors,"We study the emergence of a magnetic resonance in the superconducting state
of the electron-doped cuprate superconductors. We show that the recently
observed resonance peak in the electron-doped superconductor
Pr$_{0.88}$LaCe$_{0.12}$CuO$_{4-\delta}$ is consistent with an overdamped spin
exciton located near the particle-hole continuum. We present predictions for
the magnetic-field dependence of the resonance mode as well as its temperature
evolution in those parts of the phase diagram where $d_{x^2-y^2}$-wave
superconductivity may coexist with an antiferromagnetic spin-density wave.",0702375v3
2011-07-08,Magnetic Resonant Mode in the Low-Energy Spin-Excitation Spectrum of Superconducting Rb2Fe4Se5 Single Crystals,"We have studied the low-energy spin-excitation spectrum of the
single-crystalline Rb2Fe4Se5 superconductor (Tc = 32 K) by means of inelastic
neutron scattering. In the superconducting state, we observe a magnetic
resonant mode centered at an energy of 14 meV and at the (0.5 0.25 0.5) wave
vector (unfolded Fe-sublattice notation), which differs from the ones
characterizing magnetic resonant modes in other iron-based superconductors. Our
finding suggests that the 245-iron-selenides are unconventional superconductors
with a sign-changing order parameter, in which bulk superconductivity coexists
with the sqrt(5) x sqrt(5) magnetic superstructure. The estimated ratios of the
resonance energy to Tc and the superconducting gap indicate moderate pairing
strength in this compound, similar to that in optimally doped 1111- and
122-pnictides.",1107.1703v2
2013-07-03,Electrically Detected Magnetic Resonance Modeling and Fitting: An Equivalent Circuit Approach,"Continuous-wave electrically detected magnetic resonance (cw-EDMR or just
EDMR) and its variants are powerful tools to investigate spin-dependent
processes in materials and devices. The use of quadrature detection improves
the quality and selectivity of EDMR analysis by allowing, for example, the
separation of individual resonant spin lines. Here we propose an equivalent
circuit model in order to better understand the EDMR quadrature signal in a
variety of different situations. The model considers not just the electrical
response of the sample but of cables and measuring circuit and its influence on
the resulting spectral lines. Recent EDMR spectra from Alq3 based OLEDs, as
well as from a-Si:H reported in the literature, were successfully described by
the model. Moreover, the model allows the implementation of a fitting routine
that can be easily used to determine accurate values of crucial parameters such
as g-factor and linewidth of the resonant lines.",1307.1022v1
2015-03-19,Evidence for $Δ(2200)7/2^-$ from photoproduction and consequence for chiral-symmetry restoration at high mass,"We report a partial-wave analysis of new data on the double-polarization
variable $E$ for the reactions $\gamma p\to \pi^+ n$ and $\gamma p\to \pi^0 p$
and of further data published earlier. The analysis within the Bonn-Gatchina
(BnGa) formalism reveals evidence for a poorly known baryon resonance, the
one-star $\Delta(2200)7/2^-$. This is the lowest-mass $\Delta^*$ resonance with
spin-parity $J^P=7/2^-$. Its mass is significantly higher than the mass of its
parity partner $\Delta(1950)7/2^+$ which is the lowest-mass $\Delta^*$
resonance with spin-parity $J^P=7/2^+$. It has been suggested that chiral
symmetry might be restored in the high-mass region of hadron excitations, and
that these two resonances should be degenerate in mass. Our findings are in
conflict with this prediction.",1503.05774v2
2011-06-20,Symmetric Rotating Wave Approximation for the Generalized Single-Mode Spin-Boson System,"The single-mode spin-boson model exhibits behavior not included in the
rotating wave approximation (RWA) in the ultra and deep-strong coupling
regimes, where counter-rotating contributions become important. We introduce a
symmetric rotating wave approximation that treats rotating and counter-rotating
terms equally, preserves the invariances of the Hamiltonian with respect to its
parameters, and reproduces several qualitative features of the spin-boson
spectrum not present in the original rotating wave approximation both
off-resonance and at deep strong coupling. The symmetric rotating wave
approximation allows for the treatment of certain ultra and deep-strong
coupling regimes with similar accuracy and mathematical simplicity as does the
RWA in the weak coupling regime. Additionally, we symmetrize the generalized
form of the rotating wave approximation to obtain the same qualitative
correspondence with the addition of improved quantitative agreement with the
exact numerical results. The method is readily extended to higher accuracy if
needed. Finally, we introduce the two-photon parity operator for the two-photon
Rabi Hamiltonian and obtain its generalized symmetric rotating wave
approximation. The existence of this operator reveals a parity symmetry similar
to that in the Rabi Hamiltonian as well as another symmetry that is unique to
the two-photon case, providing insight into the mathematical structure of the
two-photon spectrum, significantly simplifying the numerics, and revealing some
interesting dynamical properties.",1106.3800v2
2005-09-30,Resonating-valence-bond structure of Gutzwiller-projected superconducting wave functions,"Gutzwiller-projected (GP) wave functions have been widely used for describing
spin-liquid physics in frustrated magnets and in high-temperature
superconductors. Such wave functions are known to represent states of the
resonating-valence-bond (RVB) type. In the present work I discuss the RVB
structure of a GP singlet superconducting state with nodes in the spectrum. The
resulting state for the undoped spin system may be described in terms of the
""path integral"" over loop coverings of the lattice, thus extending the known
construction for RVB states. The problem of the topological order in GP states
may be reformulated in terms of the statistical behavior of loops. The simple
example of the projected d-wave state on the square lattice demonstrates that
the statistical behavior of loops is renormalized in a nontrivial manner by the
projection.",0509791v2
2011-12-05,Mixed partial-wave scattering with spin-orbit coupling and validity of pseudo-potentials,"We present exact solutions of two-body problem for spin-1/2 fermions with
isotropic spin-orbit(SO) coupling and interacting with an arbitrary short-range
potential. We find that in each partial-wave scattering channel, the
parametrization of two-body wavefunction at short inter-particle distance
depends on the scattering amplitudes of all channels. This reveals the mixed
partial-wave scattering induced by SO couplings. By comparing with results from
a square-well potential, we investigate the validity of original
pseudo-potential models in the presence of SO coupling. We find the s-wave
pseudo-potential provides a good approximation for low-energy solutions near
s-wave resonances, given the length scale of SO coupling much longer than the
potential range. However, near p-wave resonance the p-wave pseudo-potential
gives low-energy solutions that are qualitatively different from exact ones,
based on which we conclude that the p-wave model can not be applied to the
fermion system if the SO coupling strength is larger or comparable to the Fermi
momentum.",1112.1122v2
2016-07-11,Low loss spin wave resonances in organic-based ferrimagnet vanadium tetracyanoethylene thin films,"We experimentally demonstrate high quality factor spin wave resonances in an
encapsulated thin film of the organic-based ferrimagnet vanadium
tetracyanoethylene (V[TCNE]$_\textit{x~2}$) coated on an a-plane sapphire
substrate by low temperature chemical vapor deposition. The thickness standing
wave modes are observed in a broad frequency range (1 GHz ~ 5 GHz) with high
quality factor exceeding 3,200 in ambient air at room temperature, rivaling
those of inorganic magnetic materials. The exchange constant of
V[TCNE]$_\textit{x~2}$, a crucial material parameter for future study and
device design of the V[TCNE]$_\textit{x~2}$, is extracted from the measurement
with a value of $(4.61\pm 0.35)\times 10^{-16} \mathrm{\: m^{2}}$. Our result
establishes the feasibility of using organic-based materials for building
hybrid magnonic devices and circuits.",1607.03041v2
2022-01-12,The angular dependence of magnetization dynamics induced by a GHz range strain pulse,"The dynamics of magnetization is important in spintronics, where the coupling
between phonon and magnon attracts much attention. In this work, we study the
angular dependence of the coupling between longitudinal-wave phonon and magnon.
We investigated the magnetization dynamics using the time-resolved
magneto-optical Kerr effect, which allows measuring spin-wave resonances and
the magnetic echo signal. The frequency, mode number, and amplitude of the
spin-wave resonance change with the out-of-plane angle of the external magnetic
field. The amplitude of the magnetic echo signal caused by the strain pulse
also changes with the angle. We calculate these angular dependences based on
the Landau-Lifshitz-Gilbert equation and find that the angles of the external
field and magnetic moment are important factors for the phonon-magnon coupling
when phonon propagates in the thickness direction under the out-of-plane
magnetic field.",2201.04396v1
2020-02-05,Spin Resonances in Iron-Selenide High-Tc Superconductors by Proximity to Hidden Spin Density Wave,"Recent inelastic neutron scattering studies by Pan et al., Nature
Communications 8, 123 (2017), find evidence for spin excitations at energies
above the quasi-particle gap in an iron-selenide high-Tc superconductor. The
momenta of the spin excitations form a diamond around the checkerboard
wavevector, Q_AF, that is associated with the square lattice of iron atoms that
makes up the system. It has been suggested that such a ""hollowed-out""
spin-excitation spectrum is due to hidden Neel order. We study such a hidden
spin-density wave (hSDW) state that results from nested Fermi surfaces at the
center and at the corner of the unfolded Brillouin zone. It emerges within mean
field theory from an extended Hubbard model over a square lattice of iron atoms
that contain the minimal d_xz and d_yz orbitals. Opposing Neel order exists
over the isotropic d+ = d_xz + i d_yz and d- = d_xz - i d_yz orbitals. The
dynamical spin susceptibility of the hSDW is computed within the random phase
approximation, at perfect nesting. Unobservable Goldstone modes that disperse
acoustically are found at Q_AF. A threshold is found in the spectrum of
observable spin excitations that forms a ""floating ring"" at Q_AF also. The ring
threshold moves down in energy toward zero with increasing Hund's Rule
coupling, while it moves up in energy with increasing magnetic frustration.
Comparison with the normal-state features of the spin-excitation spectrum shown
by electron-doped iron selenide is made. Also, recent predictions of a Lifshitz
transition from the nested Fermi surfaces to Fermi surface pockets at the
corner of the folded Brillouin zone will be discussed.",2002.01732v2
2021-07-20,Measuring binary black hole orbital-plane spin orientations,"Binary black hole spins are among the key observables for gravitational wave
astronomy. Among the spin parameters, their orientations within the orbital
plane, $\phi_1$, $\phi_2$ and $\Delta \phi=\phi_1-\phi_2$, are critical for
understanding the prevalence of the spin-orbit resonances and merger recoils in
binary black holes. Unfortunately, these angles are particularly hard to
measure using current detectors, LIGO and Virgo. Because the spin directions
are not constant for precessing binaries, the traditional approach is to
measure the spin components at some reference stage in the waveform evolution,
typically the point at which the frequency of the detected signal reaches 20
Hz. However, we find that this is a poor choice for the orbital-plane spin
angle measurements. Instead, we propose measuring the spins at a fixed
dimensionless time or frequency near the merger. This leads to significantly
improved measurements for $\phi_1$ and $\phi_2$ for several gravitational wave
events. Furthermore, using numerical relativity injections, we demonstrate that
$\Delta \phi$ will also be better measured near the merger for louder signals
expected in the future. Finally, we show that numerical relativity surrogate
models are key for reliably measuring the orbital-plane spin orientations, even
at moderate signal-to-noise ratios like $\sim 30-45$.",2107.09692v4
2022-03-31,Constraining black-hole binary spin precession and nutation with sequential prior conditioning,"We investigate the detectability of sub-dominant spin effects in merging
black-hole binaries using current gravitational-wave data. Using a
phenomenological model that separates the spin dynamics into precession
(azimuthal motion) and nutation (polar motion), we present constraints on the
resulting amplitudes and frequencies. We also explore current constraints on
the spin morphologies, indicating if binaries are trapped near spin-orbit
resonances. We dissect such weak effects from the signals using a sequential
prior conditioning approach, where parameters are progressively re-sampled from
their posterior distribution. This allows us to investigate whether the data
contain additional information beyond what is already provided by quantities
that are better measured, namely the masses and the effective spin. For the
current catalog of events, we find no significant measurements of weak spin
effects such as nutation and spin-orbit locking. We synthesize a source with a
high nutational amplitude and show that near-future detections will allow us to
place powerful constraints, hinting that we may be at the cusp of detecting
spin nutations in gravitational-wave data.",2204.00026v3
2022-11-10,Static and dynamic magnetic properties of the spin-5/2 triangle lattice antiferromagnet Na3Fe(PO4)2 studied by 31P NMR,"$^{31}$P nuclear magnetic resonance (NMR) measurements have been carried out
to investigate the magnetic properties and spin dynamics of Fe$^{3+}$ ($S$ =
5/2) spins in the two-dimensional triangular lattice (TL) compound
Na$_3$Fe(PO$_4$)$_2$. The temperature ($T$) dependence of nuclear spin-lattice
relaxation rates ($1/T_1$) shows a clear peak around N\'eel temperature,
$T_{\rm N} = 10.9$~K, corresponding to an antiferromagnetic (AFM) transition.
From the temparature dependence of NMR shift ($K$) above $T_{\rm N}$, an
exchange coupling between Fe$^{3+}$ spins was estimated to be $J/k_{\rm
B}\simeq 1.9$~K using the spin-5/2 Heisenberg isotropic-TL model. The
temperature dependence of $1/T_1T$ divided by the magnetic susceptibility
($\chi$), $1/T_1T\chi$, above $T_{\rm N}$ proves the AFM nature of spin
fluctuations below $\sim$ 50 K in the paramagnetic state. In the magnetically
ordered state below $T_{\rm N}$, the characteristic rectangular shape of the
NMR spectra is observed, indicative of a commensurate AFM state in its ground
state. The strong temperature dependence of 1/$T_1$ in the AFM state is well
explained by the two-magnon (Raman) process of the spin waves in a 3D
antiferromagnet with a spin-anisotropy energy gap of 5.7 K. The temperature
dependence of sublattice magnetization is also well reproduced by the spin
waves. Those results indicate that the magnetically ordered state of
Na$_3$Fe(PO$_4$)$_2$ is a conventional 3D AFM state, and no obvious spin
frustration effects were detected in its ground state.",2211.05921v1
2024-03-15,Spontaneous spin chirality reversal and competing phases in the topological magnet EuAl$_4$,"We demonstrate the spontaneous reversal of spin chirality in a single crystal
sample of the intermetallic magnet EuAl$_4$. We solve the nanoscopic nature of
each of the four magnetically phases of EuAl$_4$ using resonant magnetic x-ray
scattering, and demonstrate all four phases order with single-k incommensurate
magnetic modulation vectors. Below 15.4 K the system forms a spin density
modulated spin structure where the spins are orientated in the ab plane
perpendicular to the orientation of the magnetic propagation vector. Below 13.2
K a second spin density wave orders with moments aligned parallel to the
c-axis, such that the two spin density wave orders coexist. Below 12.2 K a
magnetic helix of a single chirality is stabilised across the entire sample.
Below 10 K the chirality of the magnetic helix reverses, and the sample remains
a single chiral domain. Concomitant with the establishment of the helical
magnetic ordering is the lowering of the crystal symmetry to monoclinic, as
evidenced the formation of uniaxial charge and spin strip domains. A group
theoretical analysis demonstrates that below 12.2 K the symmetry lowers to
polar monoclinic, which is necessary to explain the observed asymmetry in the
chiral states of the magnetic helix and the spin chiral reversal. We find that
in every magnetically ordered phase of EuAl4 the in-plane moment is
perpendicular to the orientation of the magnetic propagation vector, which we
demonstrate is favoured by magnetic dipolar interactions.",2403.10159v1
2007-03-12,Interactions between Multipolar Nuclear Transitions and Gravitational Waves,"Interactions between multipolar nuclear transitions and gravitational waves
(GWs) are theoretically investigated. Two nonclassical scenarios of the GW
detection are suggested. We demonstrate in this report that the long-lived
Moessbauer nuclides of multipolar transitions are suitable transducers to
detect the impinging GWs. Shape deformation and spin flip of nucleus are
derived from the Hamiltonian with gravity interaction. The GWs generate a
nuclear quadrupole deformation in analogy with the Stark effect, of which the
electric field generates the dipole deformation of electron orbits. Likewise in
analogy with the nuclear magnetic resonance that the rotating radio-frequency
field flips the nuclear spin, the GWs flip the nuclear spin by the resonant
helicity-rotation-gravity coupling. The high energy states of the quadrupole
deformation in heavy nuclides can dramatically speed up the multipolar
transitions, which may be important for the GW detection particularly in the
low frequency band, ranging from 100 nHz to 1 Hz.",0703066v2
2010-11-05,Incommensurate spin-density wave and multiband superconductivity in Na$_{x}$FeAs as revealed by nuclear magnetic resonance,"We report a $^{23}$Na and $^{75}$As nuclear magnetic resonance (NMR)
investigation of Na$_{x}$FeAs series ($x=1$, 0.9, 0.8) exhibiting a
spin-density wave (SDW) order below $T_{\rm SDW}=45$, 50 and 43 K for $x=1$,
0.9, 0.8, respectively, and a bulk superconductivity below $T_c\approx 12$ K
for x=0.9. Below $T_{\rm SDW}$, a spin-lattice relaxation reveals the presence
of gapless particle-hole excitations in the whole $x$ range, meaning that a
portion of the Fermi surface remains gapless. The superconducting fraction as
deduced from the bulk susceptibility scales with this portion, while the SDW
order parameter as deduced from the NMR linewidth scales inversely with it. The
NMR lineshape can only be reproduced assuming an incommensurate (IC) SDW. These
findings qualitatively correspond to the mean-field models of competing
interband magnetism and intraband superconductivity, which lead to an IC SDW
order coexisting with superconductivity in part of the phase diagram.",1011.1387v2
2011-05-12,"Complete set of polarization transfer observables for the ${}^{16}{\rm O}(\vec{p},\vec{n}){}^{16}{\rm F}$ reaction at 296 MeV and 0 degrees","We report measurements of the cross section and a complete set of
polarization transfer observables for the ${}^{16}{\rm
O}(\vec{p},\vec{n}){}^{16}{\rm F}$ reaction at a bombarding energy of $T_p$ =
296 MeV and a reaction angle of $\theta_{\rm lab}$ = $0^{\circ}$.
  The data are compared with distorted-wave impulse approximation calculations
employing the large configuration-space shell-model (SM) wave functions.
  The well-known Gamow-Teller and spin-dipole (SD) states at excitation
energies of $E_x$ $\lesssim$ 8 MeV have been reasonably reproduced by the
calculations except for the spin--parity $J^{\pi}$ = $2^-$ state at $E_x$ =
5.86 MeV.
  The SD resonance at $E_x$ $\simeq$ 9.5 MeV appears to have more $J^{\pi}$ =
$2^-$ strength than $J^{\pi}$ = $1^-$ strength, consistent with the
calculations.
  The data show significant strength in the spin-longitudinal polarized cross
section $ID_L(0^{\circ})$ at $E_x$ $\simeq$ 15 MeV, which indicates existence
of the $J^{\pi}$ = $0^-$ SD resonance as predicted in the SM calculations.",1105.2449v2
2014-05-28,Electronic control of the spin-wave damping in a magnetic insulator,"It is demonstrated that the decay time of spin-wave modes existing in a
magnetic insulator can be reduced or enhanced by injecting an in-plane dc
current, $I_\text{dc}$, in an adjacent normal metal with strong spin-orbit
interaction. The demonstration rests upon the measurement of the ferromagnetic
resonance linewidth as a function of $I_\text{dc}$ in a 5~$\mu$m diameter
YIG(20nm){\textbar}Pt(7nm) disk using a magnetic resonance force microscope
(MRFM). Complete compensation of the damping of the fundamental mode is
obtained for a current density of $\sim 3 \cdot 10^{11}\text{A.m}^{-2}$, in
agreement with theoretical predictions. At this critical threshold the MRFM
detects a small change of static magnetization, a behavior consistent with the
onset of an auto-oscillation regime.",1405.7415v1
2014-10-02,Investigation of the temperature-dependence of ferromagnetic resonance and spin waves in Co2FeAl0.5Si0.5,"Co2FeAl0.5Si0.5 (CFAS) is a Heusler compound that is of interest for
spintronics applications, due to its high spin polarization and relatively low
Gilbert damping constant. In this study, the behavior of ferromagnetic
resonance as a function of temperature was investigated in CFAS, yielding a
decreasing trend of damping constant as the temperature was increased from 13
to 300 K. Furthermore, we studied spin waves in CFAS using both frequency
domain and time domain techniques, obtaining group velocities and attenuation
lengths as high as 26 km/s and 23.3 um, respectively, at room temperature.",1410.0439v1
2014-12-18,Exchange Magnon-Polaritons in Microwave Cavities,"We formulate a scattering theory to study magnetic films in microwave
cavities beyond the independent-spin and rotating wave approximations of the
Tavis-Cummings model. We demonstrate that strong coupling can be realized not
only for the ferromagnetic resonance (FMR) mode, but also for spin wave
resonances (SWRs); the coupling strengths are mode dependent and decrease with
increasing mode index. The strong coupling regime can be also accessed
electrically by spin pumping into a metal contact.",1412.5809v3
2016-02-07,The Inward Dispersion of the Neutron Scattering Experiments in HTSC Cuprates,"The theory of the high temperature superconducting cuprates, which is based
on the condensation of holes into strings in checker-board geometry, was
successful to explain the elastically scattered Neutrons by spin waves. Here it
is extended to analyze the inward dispersion curve of its inelastic
counterpart, up to the resonance energy- . This extension is done by applying
the perturbation theory of the linear response to the condensed strings. The
approximated susceptibility is derived by means of the ring diagram. The
dispersion relation is obtained from the dispersion of the poles of the
susceptibility integral. It is found that the particle anti-particle pair that
yields the susceptibility is the time reversal pair where the particle momentum
is in phase A, and the anti-particle momentum is in phase B. The dispersion is
found to be in agreement with experiment, subject to some suggested
corrections. The weak intensity by the resonance energy, as well as the
dispersion, is speculated to be modified due to interference with spin waves
that are caused by direct spin flip, as in the mother undoped materials.",1602.05089v3
2014-04-30,3D Structures of equatorial waves and the resulting superrotation in the atmosphere of a tidally locked hot Jupiter,"Three-dimensional equatorial trapped waves excited by stellar isolation and
the resulting equatorial superrotating jet in a vertical stratified atmosphere
of a tidally-locked hot Jupiter are investigated. Taking the hot Jupiter HD
189733b as a fiducial example, we analytically solve a set of linear equations
subject to stationary stellar heating with a uniform zonal-mean flow included.
We also extract wave information in the final equilibrium state of the
atmosphere from the radiative hydrodynamical simulation for HD 189733b by
Dobbs-Dixon & Agol (2013). We find that the analytic wave solutions are able to
qualitatively explain the three-dimensional simulation results. Studying the
vertical structure of waves allows us to explore new wave features such as the
westward tilt of wavefronts related to the Rossby-wave resonance as well as
double gyres of dispersive Rossby waves. We also make an attempt to apply our
linear wave analysis to explain some numerical features associated with the
equatorial jet development seen in the GCM by Showman & Polvani (2011). During
the spin-up phase of the equatorial jet, the acceleration of the jet as a
result of the divergence of the wave momentum flux can be in principle boosted
by the Rossby-wave resonance as the superrotating jet speed is close to the
phase speed of the Rossby waves. However, we also find that as the jet speed
increases, the Rossby-wave structure shifts eastward, while the Kelvin-wave
structure remains approximately stationary, leading to the decline of the
acceleration rate. Our analytic model of jet evolution implies that there
exists only one stable equilibrium state of the atmosphere, possibly implying
that the final state of the atmosphere is independent of initial conditions in
the linear regime. Limitations and future improvements are also discussed.",1405.0003v2
2019-01-18,Four-wave mixing in spin-orbit coupled Bose-Einstein condensates,"We describe possibilities of spontaneous, degenerate four-wave mixing (FWM)
processes in spin-orbit coupled Bose-Einstein condensates. Phase matching
conditions (i.e., energy and momentum conservation laws) in such systems allow
one to identify four different configurations characterized by involvement of
distinct spinor states in which such a process can take place. We derived these
conditions from first principles and then illustrated dynamics with direct
numerical simulations. We found, among others, the unique configuration, where
both probe waves have smaller group velocity than pump wave and proved
numerically that it can be observed experimentally under proper choice of the
parameters. We also reported the case when two different FWM processes can
occur simultaneously. The described resonant interactions of matter waves is
expected to play important role in the experiments of BEC with artificial gauge
fields. Beams created by FWM processes are important source of correlated
particles and can be used the experiments testing quantum properties of atomic
ensembles.",1901.06173v3
2023-02-22,Advanced magnon-optic effects with spin-wave leaky modes,"We numerically demonstrate the excitation of leaky spin waves (SWs) guided
along a ferromagnetic stripe by an obliquely incident SW beam on the thin film
edge placed below the stripe. During propagation, leaky waves emit energy back
to the layer in the form of plane waves and several laterally shifted parallel
SW beams. This resonance excitation, combined with interference effects of the
reflected and re-emitted waves, results in the magnonic Woods anomaly and
significant increase of the Goos-Hanchen shift magnitude. Hence, we provide a
unique platform to control SW reflection and to transfer SWs from a 2D platform
into the 1D guiding mode that can be used to form a transdimensional magnonic
router.",2302.11507v3
1999-06-03,A relation between the resonance neutron peak and ARPES data in cuprates,"We argue that the resonant peak observed in neutron scattering experiments on
superconducting cuprates and the peak/dip/hump features observed in ARPES
measurements are byproducts of the same physical phenomenon. We argue that both
are due to feedback effects on the damping of spin fluctuations in a $d-$wave
superconductor. We consider the spin-fermion model at strong coupling, solve a
set of coupled integral equations for fermionic and bosonic propagators and
show that the dynamical spin susceptibility below $T_c$ possesses the resonance
peak at $\Omega_{res} \propto \xi^{-1}$.
  The scattering of these magnetic excitations by electrons gives rise to a
peak/dip/hump behavior of the electronic spectral function, the peak-dip
separation is exactly $\Omega_{res}$.",9906051v1
1998-07-08,Lorentz Covariant Spin-Grouping of Baryon Resonances,"A well pronounced spin--grouping of baryon resonances to O(4) partial waves
is found in baryon spectra and shown to be well interpreted in terms of Lorentz
group representations of the type (1/2 +l', 1/2 +l')* [(1/2, 0)+(0,1/2)] with
l' integer. In this way the relativistic description of finite dimensional
resonance towers containing higher-spin states becomes possible. It is further
argued that the nucleon excitations into the l'=1 and l'=2 multiplets are
chiral phase transitions.",9807292v2
2008-05-28,Broadband electrically detected magnetic resonance of phosphorus donors in a silicon field-effect transistor,"We report electrically detected magnetic resonance of phosphorus donors in a
silicon field-effect transistor. An on-chip transmission line is used to
generate the oscillating magnetic field allowing broadband operation. At
milli-kelvin temperatures, continuous wave spectra were obtained up to 40 GHz,
using both magnetic field and microwave frequency modulation. The spectra
reveal the hyperfine-split electron spin resonances characteristic for Si:P and
a central feature which displays the fingerprint of spin-spin scattering in the
two-dimensional electron gas.",0805.4244v1
2009-05-21,Spin Gap and Resonance at the Nesting Wavevector in Superconducting FeSe0.4Te0.6,"Neutron scattering is used to probe magnetic excitations in
FeSe_{0.4}Te_{0.6} (T_c=14 K). Low energy spin fluctuations are found with a
characteristic wave vector $(0.5,0.5,L)$ that corresponds to Fermi surface
nesting and differs from Q_m=(\delta,0,0.5) for magnetic ordering in
Fe_{1+y}Te. A spin resonance with \hbar\Omega_0=6.5 meV \approx 5.3 k_BT_c and
\hbar\Gamma=1.25 meV develops in the superconducting state from a normal state
continuum. We show that the resonance is consistent with a bound state
associated with s+/- superconductivity and imperfect quasi-2D Fermi surface
nesting.",0905.3559v1
2016-10-04,Hourglass dispersion and resonance of magnetic excitations in the superconducting state of the single-layer cuprate HgBa2CuO4+δ near optimal doping,"We use neutron scattering to study magnetic excitations near the
antiferromagnetic wave vector in the underdoped single-layer cuprate
HgBa2CuO4+{\delta} (superconducting transition temperature Tc ~ 88 K, pseudogap
temperature T* ~ 220 K). The response is distinctly enhanced below T* and
exhibits a Y-shaped dispersion in the pseudogap state, whereas the
superconducting state features an X-shaped (hourglass) dispersion and a further
resonance-like enhancement. A large spin gap of about 40 meV is observed in
both states. This phenomenology is reminiscent of that exhibited by bilayer
cuprates. The resonance spectral weight, irrespective of doping and compound,
scales linearly with the putative binding energy of a spin-exciton described by
an itinerant-spin formalism.",1610.01097v1
2014-06-02,"A high-frequency electron paramagnetic resonance spectrometer for multi-dimensional, -frequency and -phase pulsed measurements","We describe instrumentation for a high-frequency electron paramagnetic
resonance (EPR) and pulsed electron-electron double resonance (PELDOR)
spectroscopy. The instrumentation is operated in the frequency range of
107$-$120 GHz and 215$-$240 GHz and in the magnetic field range of 0$-$12.1
Tesla. The spectrometer consisting of a high-frequency high-power solid-state
source, a quasioptical system, a phase-sensitive detection system, a
cryogenic-free superconducting magnet and a $^4$He cryostat enables
multi-frequency continuous-wave EPR spectroscopy as well as pulsed EPR
measurements with a few hundred nanosecond pulses. Here we discuss the details
of the design and the pulsed EPR sensitivity of the instrumentation. We also
present performance of the instrumentation in unique experiments including
PELDOR spectroscopy to probe correlations in an insulating electronic spin
system and application of dynamical decoupling techniques to extend spin
coherence of electron spins in an insulating solid-state system.",1406.0227v1
2022-04-26,Resonances in heavy meson - heavy baryon coupled-channel interactions,"The interactions of $\bar{D}^{(*)} \Lambda_c - \bar{D}^{(*)}\Sigma_c^{(*)}$
are studied within the framework of a dynamical coupled-channel approach. A
series of bound states and resonances with different spin and parity are
dynamically generated in the hidden charm sector. Four $S$-wave bound states
are found in the mass range of 4.3 to 4.5 GeV, close to the pentaquark states
observed by LHCb. Two of the states have a spin parity of $J^P= 1/2^-$ and the
other two have $J^P=3/2^-$. In addition, several resonances with different spin
and parity in higher partial waves are predicted.",2204.12122v1
2023-06-24,Magnon confinement in an all-on-chip YIG cavity resonator using hybrid YIG/Py magnon barriers,"Confining magnons in cavities can introduce new functionalities to magnonic
devices, enabling future magnonic structures to emulate established photonic
and electronic components. As a proof-of-concept, we report magnon confinement
in a lithographically defined all-on-chip YIG cavity created between two
YIG/Permalloy bilayers. We take advantage of the modified magnetic properties
of covered/uncovered YIG film to define on-chip distinct regions with
boundaries capable of confining magnons. We confirm this by measuring multiple
spin pumping voltage peaks in a 400 nm wide platinum strip placed along the
center of the cavity. These peaks coincide with multiple spin-wave resonance
modes calculated for a YIG slab with the corresponding geometry. The
fabrication of micrometer-sized YIG cavities following this technique
represents a new approach to control coherent magnons, while the spin pumping
voltage in a nanometer-sized Pt strip demonstrates to be a non-invasive local
detector of the magnon resonance intensity.",2306.14029v2
2012-12-21,Superconductivity and magnetic fluctuations in electron-doped cobaltate superconductors,"We study the interplay between superconductivity and antiferromagnetic spin
fluctuations in electron-doped cobaltate Na$_{x}$CoO$_{2}\cdot y$H$_{2}$O based
on the kinetic energy driven superconductivity mechanism. We show that the
superconducting state is governed by both charge carrier pairing and
quasiparticle coherent, and displays a common dome-shaped phase diagram in
agreement with experimental results. By calculating the dynamical spin
structure factor, we theoretically find that the magnetic excitation shows a
commensurate resonance peak, which locates at antiferromagnetic wave vector $Q
(\frac{2\pi}{3},\frac{2\pi}{\sqrt{3}})$ for a broad range of low energies, then
evolves outward into six incommensurate magnetic scattering peaks with
increasing energy. Such commensurate-incommensurate spin resonance excitation
should be measured by the inelastic neutron scattering technique (INS). Our
present results strongly suggest that magnetic resonance can indeed be one of
the fundamental features in doped Mott insulators.",1212.5367v1
2016-01-08,Current Control of Magnetic Anisotropy via Stress in a Ferromagnetic Metal Waveguide,"We demonstrate that in-plane charge current can effectively control the spin
precession resonance in an Al2O3/CoFeB/Ta heterostructure. Brillouin Light
Scattering (BLS) was used to detect the ferromagnetic resonance field under
microwave excitation of spin waves at fixed frequencies. The current control of
spin precession resonance originates from modification of the in-plane uniaxial
magnetic anisotropy field H_k, which changes symmetrically with respect to the
current direction. Numerical simulation suggests that the anisotropic stress
introduced by Joule heating plays an important role in controlling H_k. These
results provide new insights into current manipulation of magnetic properties
and have broad implications for spintronic devices.",1601.02048v1
2019-02-07,Unidirectional anisotropy in cubic FeGe with antisymmetric spin-spin-coupling,"We report strong unidirectional anisotropy in bulk polycrystalline B20 FeGe
measured by ferromagnetic resonance spectroscopy. Bulk and micron-sized samples
were produced and analytically characterized. FeGe is a B20 compound with
inherent Dzyaloshinskii-Moriya interaction. Lorenz microscopy confirms a
skyrmion lattice at $190 \; \text{K}$ in a magnetic field of 150 mT.
Ferromagnetic resonance was measured at $276 \; \text{K} \pm 1 \; \text{K}$,
near the Curie temperature. Two resonance modes were observed, both exhibit a
unidirectional anisotropy of $K=1153 \; \text{J/m}^3 \pm 10 \; \text{J/m}^3$ in
the primary, and $K=28 \; \text{J/m}^3 \pm 2 \; \text{J/m}^3$ in the secondary
mode, previously unknown in bulk ferromagnets. Additionally, about 25 standing
spin wave modes are observed inside a micron-sized FeGe wedge, measured at room
temperature ($\sim \; 293$ K). These modes also exhibit unidirectional
anisotropy.",1902.02665v2
2022-01-11,"Prospects for Spin-Parity Determination of Excited Baryons via the $\mathbf{\overlineΞ^+Λ\,K^-}$ Final State with PANDA","A study of the baryon excitation spectra provides a deep insight into the
inner structure of baryons. Most of the world-wide efforts have been directed
towards $N^*$ and $\Delta^*$ spectroscopy. Complementary data from double and
triple strange baryon spectra are lacking and foreseen to be obtained with the
PANDA experiment in the near future. Earlier Monte Carlo studies demonstrated
that with an expected cross section in the order of $\mu$b, PANDA will be able
to copiously observe the channel $\bar{p}p\rightarrow
\overline{\Xi}^+\Lambda\,K^-$, including the two resonances
$\Xi\left(1690\right)^-$ and $\Xi\left(1820\right)^-$, with a negligible
background contribution. In this study, the feasibility to determine the spin
and parity of the $\Xi\left(1690\right)^-$ and $\Xi\left(1820\right)^-$
resonances is investigated by making use of a partial wave analysis employing
the PAWIAN software. The presented results demonstrate the capability of the
PANDA experiment to determine the spin-parity of these resonances with a few
days of data taking.",2201.03852v2
2005-07-29,Frustrated two-level impurities in two-dimensional antiferromagnets,"Dynamical properties of the impurity spin-$\frac12$ in 2D and quasi-2D
Heisenberg antiferromagnets (AFs) at $T\ge0$ are discussed. The specific case
of an impurity coupled symmetrically to two neighboring host spins is
considered. The specific feature of this problem is that the defect is
degenerate (frustrated) being located in zero molecular field. It is shown that
this problem can be described by spin-boson model without tunneling term and
with a more complex interaction. We demonstrate that the effect of the host
system on the defect is completely described by the spectral function. It is
found within the spin-wave approximation that for not too small $\omega$ the
spectral function is proportional to $\omega^2/J^3$, where $J$ is the exchange
constant between the host spins. The defect dynamical susceptibility is derived
using Abrikosov's pseudofermion technique and diagrammatic expansion. The
calculations are performed within the fourth order of the dimensionless
coupling parameter $f$. It is found that transverse impurity susceptibility
$\chi_\perp(\omega)$ has a Lorenz peak with the width proportional to
$f^4J(T/J)^3$ which disappears at T=0, and a non-resonant term. The later term
diverges logarithmically as $\omega,T \to 0$. The static susceptibility
$\chi(0)$ has the free-spin-like contribution $1/(4T)$, and a logarithmic
correction proportional to $f^2\ln(J/T)$. The influence of finite concentration
of the defects $n$ on the low-temperature properties of AF is also
investigated. A logarithmic correction to spin-wave velocity of the form
$nf^4\ln|J/\omega|$ and an anomalous damping of spin waves proportional to
$nf^4|\omega|$ are obtained.",0507704v2
2013-09-24,Many-body corrections to ESR energy and spin-wave excitations in two-dimensional systems with Bychkov-Rashba spin splitting,"We report effects of electron-electron (\emph{e-e}) interaction on electron
spin resonance (ESR) in perpendicular magnetic field in two-dimensional (2D)
systems with Bychkov-Rashba spin splitting induced by spin-orbit interaction
(SOI) and structural inversion asymmetry (SIA). Using the Hartree-Fock
approximation, we demonstrate that the SIA results in non-zero many-body
corrections to the ESR energy and the energy of spin wave excitations. We
discover that the \emph{e-e} interaction in 2D systems with SIA not only can
enhance the ESR energy but can also lead to the ESR energy reduction. The
magnitude of this effect exhibits remarkable features in a wide range of
parameters relevant to experiment: it is found to be rather sensitive to the
sign of g-factor and the filling factor of Landau levels $\nu$. We derive
analytical expressions for many-body corrections to ESR energy and the
dispersion of spin wave excitations for the case of $\nu\leq 2$. We have found
out that \emph{e-e} interaction does not affect the ESR energy in the case of
filling of the lowest Landau level ($\nu\leq 1$) in 2D systems with positive
g-factors even at arbitrarily large values of Bychkov-Rashba constant. The
many-body renormalization of ESR energy in the case of fractional Quantum Hall
effect is also discussed.",1309.6098v1
2019-09-23,"Coherent spin dynamics of solitons in the organic spin chain compounds ($o$-DMTTF)$_2X$ ($X$ = Cl, Br)","We studied the magnetic properties, in particular dynamics, of the correlated
spins associated with natural defects in the organic spin chain compounds
($o$-DMTTF)$_2X$ ($X$ = Br, Cl) by means of electron spin resonance (ESR)
spectroscopy. Both materials exhibit spin-Peierls transitions at temperatures
around 50 K [P. Foury-Leylekian et al. Phys. Rev. B 84, 195134 (2011)], which
allow a separation of the properties of defects inside the chains from the
magnetic response of the spin chains. Indeed, continuous wave ESR measurements
performed over a wide temperature range evidence the evolution of the spin
dynamics from being governed by the spins in the chains at elevated
temperatures to a low-temperature regime which is dominated by defects within
the spin-dimerized chains. Such defects polarize the antiferromagnetically
coupled spins in their vicinity, thereby leading to a finite local alternating
magnetization around the defect site which can be described in terms of a
soliton, i.e. a spin 1/2 quasiparticle built of many correlated spins, pinned
to the defect. In addition, contributions of triplon excitations of the
spin-dimerized state to the ESR response below the transition temperature were
observed which provides a spectroscopic estimate for the spin-gap of the
studied systems. Moreover, details of spin dynamics deep in the spin-Peierls
phase were investigated by pulse ESR experiments which revealed
Rabi-oscillations as signatures of coherent spin dynamics. From a comparison of
the characteristic damping times of the Rabi oscillations with measurements of
the spin relaxation times by means of primary-echo decay and CPMG methods it
becomes evident that inhomogeneities in local magnetic fields strongly
contribute to the soliton decoherence.",1909.10301v2
2010-11-29,How to complete light meson spectroscopy to M = 2410 MeV/c^2,"A measurement of transverse polarisation in pbar-p -> all-neutral final
states would almost certainly determine a complete set of partial wave
amplitudes over the mass range 1910 to 2410 MeV. This should identify all
resonances in this mass range. The experiment is technically straightforward
and cheap by present standards.",1011.6237v1
2014-02-14,Extremely high-resolution measurements of microwave magnetisation dynamics in magnetic thin films and nanostructures,"In this work we discuss the use of interferometric measurement technique to
study microwave magnetization dynamics on ferromagnetic nanostructures. We
demonstrate that in this way one can resolve features which are impossible to
resolve with broadband ferromagnetic resonance and traveling spin wave
spectroscopy otherwise.",1402.3459v1
2002-02-14,"Polarization transfer in the $^{16}$O$(p,p')$ reaction at forward angles and structure of the spin-dipole resonances","Cross sections and polarization transfer observables in the $^{16}$O$(p,p')$
reactions at 392 MeV were measured at several angles between $\theta_{lab}=$
0$^\circ$ and 14$^\circ$. The non-spin-flip (${\Delta}S=0$) and spin-flip
(${\Delta}S=1$) strengths in transitions to several discrete states and broad
resonances in $^{16}$O were extracted using a model-independent method. The
giant resonances in the energy region of $E_x=19-$27 MeV were found to be
predominantly excited by ${\Delta}L=1$ transitions. The strength distribution
of spin-dipole transitions with ${\Delta}S=1$ and ${\Delta}L=1$ were deduced.
The obtained distribution was compared with a recent shell model calculation.
Experimental results are reasonably explained by distorted-wave impulse
approximation calculations with the shell model wave functions.",0202015v2
2001-01-03,Spin and Current Correlation Functions in the \bf d-density Wave State of the Cuprates,"We calculate the spin-spin and current-current correlation functions in
states exhibiting d_{{x^2}-{y^2}}-density wave (DDW) order, d_{{x^2}-{y^2}}
superconducting order (DSC), or both types of order. The spin-spin correlation
functions in a state with both DDW and DSC order and in a state with DDW order
alone, respectively, illuminate the resonant peak seen in the superconducting
state of the underdoped cuprates and the corresponding feature seen in the
pseudogap regime. The current-current correlation function in a state with both
DDW and DSC order evinces a superfluid density with doping dependence which is
consistent with that of the underdoped cuprates. These calculations strengthen
the identification of the pseudogap with DDW order and of the underdoped
cuprates with a state with both DDW and DSC order.",0101027v2
2006-10-12,Fermi liquid instabilities in the spin channel,"We study the Fermi surface instabilities of the Pomeranchuk type in the spin
triplet channel with high orbital partial waves ($F_{l}^a ~(l>0)$). The ordered
phases are classified into two classes, dubbed the $\alpha$ and $\beta$-phases
by analogy to the superfluid $^3$He-A and B-phases. The Fermi surfaces in the
$\alpha$-phases exhibit spontaneous anisotropic distortions, while those in the
$\beta$-phases remain circular or spherical with topologically non-trivial spin
configurations in momentum space. In the $\alpha$-phase, the Goldstone modes in
the density channel exhibit anisotropic overdamping. The Goldstone modes in the
spin channel have nearly isotropic underdamped dispersion relation at small
propagating wavevectors. Due to the coupling to the Goldstone modes, the spin
wave spectrum develops resonance peaks in both the $\alpha$ and $\beta$-phases,
which can be detected in inelastic neutron scattering experiments. In the
p-wave channel $\beta$-phase, a chiral ground state inhomogeneity is
spontaneously generated due to a Lifshitz-like instability in the originally
nonchiral systems. Possible experiments to detect these phases are discussed.",0610326v2
2008-04-18,Towards quantum optics and entanglement with electron spin ensembles in semiconductors,"We discuss a technique and a material system that enable the controlled
realization of quantum entanglement between spin-wave modes of electron
ensembles in two spatially separated pieces of semiconductor material. The
approach uses electron ensembles in GaAs quantum wells that are located inside
optical waveguides. Bringing the electron ensembles in a quantum Hall state
gives selection rules for optical transitions across the gap that can
selectively address the two electron spin states. Long-lived superpositions of
these electron spin states can then be controlled with a pair of optical fields
that form a resonant Raman system. Entangled states of spin-wave modes are
prepared by applying quantum-optical measurement techniques to optical signal
pulses that result from Raman transitions in the electron ensembles.",0804.2953v1
2016-02-04,Investigation of the unidirectional spin heat conveyer effect in a 200nm thin Yttrium Iron Garnet film,"We have investigated the unidirectional spin wave heat conveyer effect in
sub-micron thick yttrium iron garnet (YIG) films using lock-in thermography
(LIT). Although the effect is small in thin layers this technique allows us to
observe asymmetric heat transport by magnons which leads to asymmetric
temperature profiles differing by several mK on both sides of the exciting
antenna, respectively. Comparison of Damon-Eshbach and backward volume modes
shows that the unidirectional heat flow is indeed due to non-reciprocal
spin-waves. Because of the finite linewidth, small asymmetries can still be
observed when only the uniform mode of ferromagnetic resonance is excited. The
latter is of extreme importance for example when measuring the inverse
spin-Hall effect because the temperature differences can result in
thermovoltages at the contacts. Because of the non-reciprocity these
thermovoltages reverse their sign with a reversal of the magnetic field which
is typically deemed the signature of the inverse spin-Hall voltage.",1602.01662v1
2016-04-22,Nanoscale control of heat and spin conductance in artificial spin chains,"We describe a mechanism to control energy and magnetisation currents in an
artificial spin-chain, consisting of an array of Permalloy nano-disks coupled
through the magneto-dipolar interaction. The chain is kept out of equilibrium
by two thermal baths with different temperatures connected to its ends, which
control the current propagation. Transport is enhanced by applying a uniform
radio frequency pump field resonating with some of the spin-wave modes of the
chain. Moreover, the two currents can be controlled independently by tuning the
static field applied on the chain. Thus we describe two effective means for the
independent control of coupled currents and the enhancement of thermal and
spin-wave conductivity in a realistic magnonics device, suggesting that similar
effects could be observed in a large class of nonlinear oscillating systems.",1604.06572v3
2017-08-18,General treatment of quantum and classical spinning particles in external fields,"We develop the general theory of spinning particles with electric and
magnetic dipole moments moving in arbitrary electromagnetic, inertial and
gravitational fields. Both the quantum-mechanical and classical dynamics is
investigated. We start from the covariant Dirac equation extended to a
spin-${\frac 12}$ fermion with anomalous magnetic and electric dipole moments
and then perform the relativistic Foldy-Wouthuysen transformation. This
transformation allows us to obtain the quantum-mechanical equations of motion
for the physical operators in the Schr\""odinger form and to establish the
classical limit of relativistic quantum mechanics. The results obtained are
then compared to the general classical description of the spinning particle
interacting with electromagnetic, inertial and gravitational fields. The
complete agreement between the quantum mechanics and the classical theory is
proven in the general case. As an application of the results obtained, we
consider the dynamics of a spinning particle in a gravitational wave and
analyze the prospects of using the magnetic resonance setup to find possible
manifestations of the gravitational wave on spin.",1708.05601v2
2021-04-26,Interpretation of multiple solutions in fully iterative GF2 and GW schemes using local analysis of two-particle density matrices,"Due to non-linear structure, iterative Green's function methods can result in
multiple different solutions even for simple molecular systems. In contrast to
the wave-function methods, a detailed and careful analysis of such molecular
solutions was not performed before. In this work, we use two-particle density
matrices to investigate local spin and charge correlators that quantify the
charge-resonance and covalent characters of these solutions. When applied
within unrestricted orbital set, spin correlators elucidate the broken symmetry
of the solutions, containing necessary information for building effective
magnetic Hamiltonians. Based on GW and GF2 calculations of simple molecules and
transition metal complexes, we construct Heisenberg Hamiltonians,
four-spin-four-center corrections, as well as biquadratic spin-spin
interactions. These Hamiltonian parametrizations are compared to prior
wave-function calculations.",2104.12751v1
2021-06-08,Spectral-fingerprinting: Microstate readout via remanence ferromagnetic resonance in artificial spin systems,"Artificial spin ices are magnetic metamaterials comprising
geometrically-tiled interacting nanomagnets. There is significant interest in
these systems for reconfigurable magnonics due to their vast microstate
landscape. Studies to-date have focused on the in-field GHz spin-wave response,
convoluting effects from applied field, nanofabrication-imperfections
('quenched disorder') and microstate-dependent dipolar field landscapes. Here,
we study artificial spin ices in pure and disordered microstates and evaluate
their zero-field spectra. Removing the applied field allows us to deconvolute
contributions to reversal dynamics and spin-wave spectra, directly measuring
the dipolar field landscape and quenched disorder. Mode-amplitude provides
population readout of nanomagnet magnetisation direction, and hence net
magnetisation as well as local vertex populations. We demonstrate
microstate-fingerprinting via distinct spectral-readout of three microstates
with identical (zero) magnetisation, supported by simulation. These results
establish remanence 'spectral-fingerprinting' as a rapid, scalable on-chip
readout of both magnetic state and nanoscale dipolar field texture, a critical
step in realising next-generation functional magnonic devices.",2106.04406v2
2023-07-13,Tracking Berry curvature effect in molecular dynamics by ultrafast magnetic x-ray scattering,"The spin-dependent Berry force is a genuine effect of Berry curvature in
molecular dynamics, which can dramatically result in spatial spin separation
and change of reaction pathways. However, the way to probe the effect of Berry
force remains challenging, because the time-reversal (TR) symmetry required for
opposite Berry forces conflicts with TR symmetry breaking spin alignment needed
to observe the effect, and the net effect could be transient for a molecular
wave packet. We demonstrate that in molecular photodissociation, the
dissociation rates can be different for molecules with opposite initial spin
directions due to Berry force. We showcase that the spatially separated spin
density, which is transiently induced by Berry force as the molecular wave
packet passes through conical intersection, can be reconstructed from the
circular dichroism (CD) of ultrafast non-resonant magnetic x-ray scattering
using free electron lasers.",2307.06523v1
2023-10-26,Spin wave behavior of a novel hopfion-like chiral state in Co/Pt nanodiscs,"This work discusses the rich phase diagram of non-trivial chiral spin
textures in confined ferromagnetic/heavy-metal (FM/HM) bilayer nanomagnets of
circular cross-section. These spin textures are realized as a minimum-energy
ground state during an external bias field sweep for a range of nanomagnet's
diameter (d). Our study, based on micromagnetic simulations, has revealed a
novel Hopfion-like state which can be stabilized for a wide range of diameters
and external magnetic fields. We explored the dynamical characteristics of this
novel Hopfion-like state under a transient magnetic field applied along the
plane's perpendicular direction. Simulation results have demonstrated the
excitation of nonreciprocal spin wave (SW) modes for this novel chiral state,
in contrast to other stabilized chiral states. These modes are characterized as
breathing and quantized radial modes, which also exhibit hybridization with
azimuthal modes. The resonant SW modes have been used to demonstrate the
switching from a Hopfion-like state to a skyrmion within a few nanoseconds of
SW excitation. Furthermore, we establish a correlation between the behavior of
excited SW modes as a function of external magnetic field strength and
underlying chiral spin texture states.",2310.17460v1
2003-05-22,Theory of spin response in underdoped cuprates as strongly fluctuating d-wave superconductors,"We study the spin dynamics in underdoped cuprates at low temperatures by
considering them as quasi two dimensional d-wave superconductors (dSC) with
strong phase fluctuations. An effective theory of spin degrees of freedom of
nodal quasiparticles coupled to vortex defects in the phase of the
superconducting order parameter is formulated. It represents the minimal
extension of the QED3 theory of the pseudogap phase into the superconducting
region. The theory predicts a single dSC-SDW transition, which may be
fluctuation induced first order, without the region of coexistence between the
two ordered phases. We compute the spin-spin correlator in the dSC, and explain
the evolution of the spin response with frequency as observed in neutron
scattering experiments on YBCO. We predict that at the frequencies much below
the resonance the (weak) spin response should become narrowly peaked at four
`diagonally' incommensurate wave vectors that span between the nodes of the
supercopnducting order parameter. These peaks represent an inherent collective
mode of the phase fluctuating dSC, the condensation of which would bring about
the SDW order in the pseudogap phase. Our interpretation of the resonance
suggests it should become more elusive in the superconductors with lower Tc, in
accord with its' conspicuous absence in LSCO.",0305512v1
2010-06-08,Dynamic spin susceptibility of superconducting cuprates: A microscopic theory of the magnetic resonance mode,"A microscopic theory of the dynamic spin susceptibility (DSS) in the
superconducting state within the t-J model is presented. It is based on an
exact representation for the DSS obtained by applying the Mori-type projection
technique for the relaxation function in terms of Hubbard operators. The static
spin susceptibility is evaluated by a sum-rule-conserving generalized
mean-field approximation, while the self-energy is calculated in the
mode-coupling approximation. The spectrum of spin excitations is studied in the
underdoped and optimally doped regions. The DSS reveals a resonance mode (RM)
at the antiferromagnetic wave vector Q = \pi(1,1) at low temperatures due to a
strong suppression of the damping of spin excitations. This is explained by an
involvement of spin excitations in the decay process besides the particle-hole
continuum usually considered in random-phase-type approximations. The spin gap
in the spin-excitation spectrum at Q plays a dominant role in limiting the
decay in comparison with the superconducting gap which results in the
observation of the RM even above $T_c$ in the underdoped region. A good
agreement with inelastic neutron-scattering experiments on the RM in YBCO
compounds is found.",1006.1525v2
2016-10-28,Insulating nanomagnets driven by spin torque,"Magnetic insulators, such as yttrium iron garnet (Y$_3$Fe$_5$O$_{12}$), are
ideal materials for ultra-low power spintronics applications due to their low
energy dissipation and efficient spin current generation and transmission.
Recently, it has been realized that spin dynamics can be driven very
effectively in micrometer-sized Y$_3$Fe$_5$O$_{12}$/Pt heterostructures by
spin-Hall effects. We demonstrate here the excitation and detection of spin
dynamics in Y$_3$Fe$_5$O$_{12}$/Pt nanowires by spin-torque ferromagnetic
resonance. The nanowires defined via electron-beam lithography are fabricated
by conventional room temperature sputtering deposition on Gd$_3$Ga$_5$O$_{12 }$
substrates and lift-off. We observe field-like and anti-damping-like torques
acting on the magnetization precession, which are due to simultaneous
excitation by Oersted fields and spin-Hall torques. The Y$_3$Fe$_5$O$_{12}$/Pt
nanowires are thoroughly examined over a wide frequency and power range. We
observe a large change in the resonance field at high microwave powers, which
is attributed to a decreasing effective magnetization due to microwave
absorption. These heating effects are much more pronounced in the investigated
nanostructures than in comparable micron-sized samples. By comparing different
nanowire widths, the importance of geometrical confinements for magnetization
dynamics becomes evident: quantized spin-wave modes across the width of the
wires are observed in the spectra. Our results are the first stepping stones
toward the realization of integrated magnonic logic devices based on
insulators, where nanomagnets play an essential role.",1610.09360v1
2020-09-22,Magnon-mediated spin currents in Tm3Fe5O12/Pt with perpendicular magnetic anisotropy,"The control of pure spin currents carried by magnons in magnetic insulator
(MI) garnet films with a robust perpendicular magnetic anisotropy (PMA) is of
great interest to spintronic technology as they can be used to carry, transport
and process information. Garnet films with PMA present labyrinth domain
magnetic structures that enrich the magnetization dynamics, and could be
employed in more efficient wave-based logic and memory computing devices. In
MI/NM bilayers, where NM being a normal metal providing a strong spin-orbit
coupling, the PMA benefits the spin-orbit torque (SOT) driven magnetization's
switching by lowering the needed current and rendering the process faster,
crucial for developing magnetic random-access memories (SOT-MRAM). In this
work, we investigated the magnetic anisotropies in thulium iron garnet (TIG)
films with PMA via ferromagnetic resonance measurements, followed by the
excitation and detection of magnon-mediated pure spin currents in TIG/Pt driven
by microwaves and heat currents. TIG films presented a Gilbert damping constant
{\alpha}~0.01, with resonance fields above 3.5 kOe and half linewidths broader
than 60 Oe, at 300 K and 9.5 GHz. The spin-to-charge current conversion through
TIG/Pt was observed as a micro-voltage generated at the edges of the Pt film.
The obtained spin Seebeck coefficient was 0.54 {\mu}V/K, confirming also the
high interfacial spin transparency.",2009.10299v1
2006-02-20,Exact Landau Levels in Two-Dimensional Electron Systems with Rashba and Dresselhaus Spin-Orbit Interactions in a Perpendicular Magnetic Field,"We study a two-dimensional electron system in the presence of both Rashba and
Dresselhaus spin-orbit interactions in a perpendicular magnetic field. Defining
two suitable boson operators and using the unitary transformations we are able
to obtain the exact Landau levels in the range of all the parameters. When the
strengths of the Rashba and Dresselhaus spin-orbit interactions are equal, a
new analytical solution for the vanishing Zeeman energy is found, where the
orbital and spin wave functions of electron are separated. It is also shown
that in this case the Zeeman and spin-orbit splittings are independent of the
Landau level index $n$. Due to the Zeeman energy, new crossing between the
eigenstates $|n, k, s=1, \sigma>$ and $|n+1, k, s^\prime =-1, \sigma^\prime>$
is produced at certain magnetic field for larger Rashba spin-orbit coupling.
This degeneracy leads to a resonant spin Hall conductance if it happens at the
Fermi level.",0602473v1
2015-03-12,Gate-control of spin-motive force and spin-torque in Rashba SOC systems,"The introduction of a strong Rashba spin orbit coupling (SOC) had been
predicted to enhance the spin motive force (SMF) [see Phys. Rev. Lett. {\bf
108}, 217202 (2012)]. In this work, we predict further enhancement of the SMF
by time modulation of the Rashba coupling $\alpha_R$, which induces an
additional electric field $E^R_d={\dot \alpha_R} m_e/e\hbar({\hat z}\times
{\mathbf m})$. When the modulation frequency is higher than the magnetization
precessing frequency, the amplitude of this field is significantly larger than
previously predicted results. Correspondingly, the spin torque on the
magnetization is also effectively enhanced. Additionally, the nature of SOC
induced spin torque in the system can be transformed from damping to
antidamping-like by modulating ${\dot \alpha_R}$. We also suggest a biasing
scheme to achieve rectification of SMF, {\it i.e.}, by application of a square
wave voltage at the resonant frequency. Finally, we numerically estimate the
resulting spin torque field arising from a Gaussian pulse time modulation of
$\alpha_R$.",1503.03651v2
2017-11-28,The magnetic and electric transverse spin density of spatially confined light,"When a beam of light is laterally confined, its field distribution can
exhibit points where the local magnetic and electric field vectors spin in a
plane containing the propagation direction of the electromagnetic wave. The
phenomenon indicates the presence of a non-zero transverse spin density. Here,
we experimentally investigate this transverse spin density of both magnetic and
electric fields, occurring in highly-confined structured fields of light. Our
scheme relies on the utilization of a high-refractive-index nano-particle as
local field probe, exhibiting magnetic and electric dipole resonances in the
visible spectral range. Because of the directional emission of dipole moments
which spin around an axis parallel to a nearby dielectric interface, such a
probe particle is capable of locally sensing the magnetic and electric
transverse spin density of a tightly focused beam impinging under normal
incidence with respect to said interface. We exploit the achieved experimental
results to emphasize the difference between magnetic and electric transverse
spin densities.",1711.10268v1
2022-04-28,Field-Assisted Sub-Terahertz Spin Pumping and Auto-Oscillation in NiO,"Spin pumping converting sub-terahertz electromagnetic waves to DC spin
currents has recently been demonstrated in antiferromagnets (AFMs) with
easy-axis magnetic anisotropy. However, easy-plane AFMs such as NiO, which are
easier to prepare experimentally, are considered to be bad candidates for spin
pumping because the N\'{e}el vector oscillation is linearly polarized, placing
a major restriction on the material choice for practical applications. Through
a case study of NiO, we show that an applied magnetic field below the spin-flop
transition can substantially modify the polarization of the resonance
eigenmodes, which enables coherent sub-terahertz spin pumping as strong as that
in easy-axis AFMs. In addition, we find that an applied magnetic field can
significantly reduce the threshold of N\'{e}el vector auto-oscillation
triggered by spin-transfer torques. These prominent field-assisted effects can
greatly facilitate spintronic device engineering in the sub-terahertz frequency
regime.",2204.13283v2
2022-10-04,Spin-orbit enhancement in Si/SiGe heterostructures with oscillating Ge concentration,"We show that Ge concentration oscillations within the quantum well region of
a Si/SiGe heterostructure can significantly enhance the spin-orbit coupling of
the low-energy conduction-band valleys. Specifically, we find that for Ge
oscillation wavelengths near $\lambda = 1.57~\text{nm}$ with an average Ge
concentration of $\bar{n}_{\text{Ge}} = 5\%$ in the quantum well region, a
Dresselhaus spin-orbit coupling is induced, at all physically relevant electric
field strengths, which is over an order of magnitude larger than what is found
in conventional Si/SiGe heterostructures without Ge concentration oscillations.
This enhancement is caused by the Ge concentration oscillations producing
wave-function satellite peaks a distance $2 \pi/\lambda$ away in momentum space
from each valley, which then couple to the opposite valley through Dresselhaus
spin-orbit coupling. Our results indicate that the enhanced spin-orbit coupling
can enable fast spin manipulation within Si quantum dots using electric dipole
spin resonance in the absence of micromagnets. Indeed, our calculations yield a
Rabi frequency $\Omega_{\text{Rabi}}/B > 500~\text{MHz/T}$ near the optimal Ge
oscillation wavelength $\lambda = 1.57~\text{nm}$.",2210.01700v2
2012-01-25,Efficient second harmonic generation in a metamaterial with two resonant modes coupled through two varactor diodes,"We present an effective method to generate second harmonic (SH) waves using
nonlinear metamaterial composed of coupled split ring resonators (CSRRs) with
varactor (variable capacitance) diodes. The CSRR structure has two resonant
modes: a symmetric mode that resonates at the fundamental frequency and an
anti-symmetric mode that resonates at the SH frequency. Resonant fundamental
waves in the symmetric mode generate resonant SH waves in the anti-symmetric
mode. The double resonance contributes to effective SH radiation. In the
experiment, we observe 19.6 dB enhancement in the SH radiation in comparison
with the nonlinear metamaterial that resonates only for the fundamental waves.",1201.5196v1
2008-06-03,Effect of the Bloch-Siegert Shift on the Frequency Responses of Rabi Oscillations in the Case of Nutation Resonance,"The dynamics of a two-level spin system dressed by bichromatic radiation is
studied under the conditions of double resonance when the frequency of one
(microwave) field is equal to the Larmor frequency of the spin system and the
frequency of the other (radio-frequency) field \omega_{rf} is close to the Rabi
frequency \omega_{1} in a micro-wave field. It is shown theoretically that Rabi
oscillations between dressed-spin states with the frequency \epsilon are
accompanied by higher-frequency oscillations at frequencies n\omega_{rf} and
n\omega_{rf}\pm \epsilon, where n = 1, 2, .... The most intense among these are
the signals corresponding to n = 1. The counter-rotating (antiresonance)
components of the RF field give rise to a shift of the dressed-state energy,
i.e., to a frequency shift similar to the Bloch-Siegert shift. In particular,
this shift is manifested as the dependence of the Rabi-oscillation frequency
\epsilon on the sign of the detuning \omega{1} -\omega{rf} from resonance. In
the case of double resonance, the oscillation amplitude is asymmetric; i.e.,
the amplitude at the sum frequency \omega_{rf} +\epsilon increases, while the
amplitude at the difference frequency \omega_{rf} -\epsilon decreases. The
predicted effects are confirmed by observations of the nutation signals of the
electron paramagnetic resonance (EPR) of centers in quartz and should be taken
into account to realize qubits with a low Rabi frequency in solids.",0806.0534v1
2017-03-09,Orbital selective neutron spin resonance in underdoped superconducting NaFe$_\textbf{0.985}$Co$_\textbf{0.015}$As,"We use neutron scattering to study the electron-doped superconducting
NaFe$_{0.985}$Co$_{0.015}$As ($T_c=14$ K), which has co-existing static
antiferromagnetic (AF) order ($T_N=31$ K) and exhibits two neutron spin
resonances ($E_{r1}\approx 3.5$ meV and $E_{r2}\approx 6$ meV) at the in-plane
AF ordering wave vector ${\bf Q}_{\rm AF}={\bf Q}_{1}=(1,0)$ in reciprocal
space. In the twinned state below the tetragonal-to-orthorhombic structural
transition $T_s$, both resonance modes appear at ${\bf Q}_{1}$ but cannot be
distinguished from ${\bf Q}_{2}=(0,1)$. By detwinning the single crystal with
uniaxial pressure along the orthorhombic $b$-axis, we find that both resonances
appear only at ${\bf Q}_{1}$ with vanishing intensity at ${\bf Q}_{2}$. Since
electronic bands of the orbital $d_{xz}$ and $d_{yz}$ characters split below
$T_s$ with the $d_{xz}$ band sinking $\sim10$ meV below the Fermi surface, our
results indicate that the neutron spin resonances in
NaFe$_{0.985}$Co$_{0.015}$As arise mostly from quasi-particle excitations
between the hole and electron Fermi surfaces with the $d_{yz}$ orbital
character.",1703.03318v1
2008-11-08,Ballistic Spin Resonance,"The phenomenon of spin resonance has had far reaching influence since its
discovery nearly 70 years ago. Electron spin resonance (ESR) driven by high
frequency magnetic fields has informed our understanding of quantum mechanics,
and finds application in fields as diverse as medicine and quantum information.
Spin resonance induced by high frequency electric fields, known as electric
dipole spin resonance (EDSR), has also been demonstrated recently. EDSR is
mediated by spin-orbit interaction (SOI), which couples the spin degree of
freedom and the momentum vector. Here, we report the observation of a novel
spin resonance due to SOI that does not require external driving fields.
Ballistic spin resonance (BSR) is driven by an internal spin-orbit field that
acts upon electrons bouncing at gigaHertz frequencies in narrow channels of
ultra-clean two-dimensional electron gas (2DEG). BSR is manifested in
electrical measurements of pure spin currents as a strong suppression of spin
relaxation length when the motion of electrons is in resonance with spin
precession. These findings point the way to gate-tunable coherent spin
rotations in ballistic nanostructures without external a.c. fields.",0811.1244v1
2006-06-19,A photonic bandgap resonator to facilitate GHz frequency conductivity experiments in pulsed magnetic fields,"We describe instrumentation designed to perform millimeter-wave conductivity
measurements in pulsed high magnetic fields at low temperatures. The main
component of this system is an entirely non-metallic microwave resonator. The
resonator utilizes periodic dielectric arrays (photonic bandgap structures) to
confine the radiation, such that the resonant modes have a high Q-factor, and
the system possesses sufficient sensitivity to measure small samples within the
duration of a magnet pulse. As well as measuring the sample conductivity to
probe orbital physics in metallic systems, this technique can detect the sample
permittivity and permeability allowing measurement of spin physics in
insulating systems. We demonstrate the system performance in pulsed magnetic
fields with both electron paramagnetic resonance experiments and conductivity
measurements of correlated electron systems.",0606476v1
2002-09-05,Chiral unitary approach to hadron spectroscopy,"The s-wave meson-baryon interaction in the $S = -1$, $S= 0$ and $S= -2$
sectors is studied by means of coupled channels, using the lowest-order chiral
Lagrangian and the N/D method or equivalently the Bethe-Salpeter equation to
implement unitarity.
  This chiral approach leads to the dynamical generation of the $\Lambda
(1405)$, $\Lambda(1670)$ and $\Sigma(1620)$ states for $S = -1$, the
$N^*(1535)$ for $S= 0$ and the $\Xi(1620)$ for $S= -2$. We look for poles in
the complex plane and extract the couplings of the resonances to the different
final states. This allows identifying the $\Lambda (1405)$ and the
$\Lambda(1670)$ resonances with $\bar{K}N$ and $K\Xi$ quasibound states,
respectively. Our results are found to be incompatible with the measured
properties of the $\Xi(1690)$ resonance, thus ruling this state out as the
remaining member of this octet of dynamically generated resonances. We
therefore assign $1/2^-$ for the spin and parity of the $\Xi(1620)$ resonance
as the $S=-2$ member of the lowest-lying $1/2^-$ octet.",0209018v1
2009-09-30,Effect of magnetic field on the spin resonance in FeTe(0.5)Se(0.5) as seen via inelastic neutron scattering,"Inelastic neutron scattering and susceptibility measurements have been
performed on the optimally-doped Fe-based superconductor FeTe(0.5)Se(0.5),
which has a critical temperature, Tc of 14 K. The magnetic scattering at the
stripe antiferromagnetic wave-vector Q = (0.5,0.5) exhibits a ""resonance"" at ~
6 meV, where the scattering intensity increases abruptly when cooled below Tc.
In a 7-T magnetic field parallel to the a-b plane, Tc is slightly reduced to ~
12 K, based on susceptibility measurements. The resonance in the neutron
scattering measurements is also affected by the field. The resonance intensity
under field cooling starts to rise at a lower temperature ~ 12 K, and the low
temperature intensity is also reduced from the zero-field value. Our results
provide clear evidence for the intimate relationship between superconductivity
and the resonance measured in magnetic excitations of Fe-based superconductors.",0910.0027v2
2016-04-19,Implications of perturbative unitarity for scalar di-boson resonance searches at LHC,"We study the constraints implied by partial wave unitarity on new physics in
the form of spin-zero di-boson resonances at LHC. We derive the scale where the
effective description in terms of the SM supplemented by a single resonance is
expected to break down depending on the resonance mass and signal
cross-section. Likewise, we use unitarity arguments in order to set
perturbativity bounds on renormalizable UV completions of the effective
description. We finally discuss under which conditions scalar di-boson
resonance signals can be accommodated within weakly-coupled models.",1604.05746v3
2015-06-29,Synchronous Spin-Exchange Optical Pumping,"We describe a new approach to precision NMR with hyperpolarized gases
designed to mitigate NMR frequency shifts due to the alkali spin exchange
field. The electronic spin polarization of optically pumped alkali atoms is
square-wave modulated at the noble-gas NMR frequency and oriented transverse to
the DC Fourier component of the NMR bias field. Noble gas NMR is driven by
spin-exchange collisions with the oscillating electron spins. On resonance, the
time-average torque from the oscillating spin-exchange field produced by the
alkali spins is zero. Implementing the NMR bias field as a sequence of alkali
2$ \pi $-pulses enables synchronization of the alkali and noble gas spins
despite a 1000-fold discrepancy in gyromagnetic ratio. We demonstrate this
method with Rb and Xe, and observe novel NMR broadening effects due to the
transverse oscillating spin exchange field. When uncompensated, the
spin-exchange field at high density broadens the NMR linewidth by an order of
magnitude, with an even more dramatic suppression (up to 70x) of the phase
shift between the precessing alkali and Xe polarizations. When we introduce a
transverse compensation field, we are able to eliminate the spin-exchange
broadening and restore the usual NMR phase sensitivity. The projected
quantum-limited sensitivity is better than 1 nHz/$\sqrt{\rm Hz}$.",1506.08797v1
2016-05-02,Electrical Detection of Magnetization Dynamics via Spin Rectification Effects,"The purpose of this article is to review the current status of a frontier in
dynamic spintronics and contemporary magnetism, in which much progress has been
made in the past decade, based on the creation of a variety of micro- and
nano-structured devices that enable electrical detection of magnetization
dynamics. The primary focus is on the physics of spin rectification effects,
which are well suited for studying magnetization dynamics and spin transport in
a variety of magnetic materials and spintronic devices. Intended to be
intelligible to a broad audience, the paper begins with a pedagogical
introduction, comparing the methods of electrical detection of charge and spin
dynamics in semiconductors and magnetic materials respectively. After that it
provides a comprehensive account of the theoretical study of both the angular
dependence and line shape of electrically detected ferromagnetic resonance
(FMR), which is summarized in a handbook formate easy to be used for analyzing
experimental data. We then review and examine the similarity and differences of
various spin rectification effects found in ferromagnetic films, magnetic
bilayers and magnetic tunnel junctions, including a discussion of how to
properly distinguish spin rectification from the spin pumping/inverse spin Hall
effect generated voltage. After this we review the broad applications of
rectification effects for studying spin waves, nonlinear dynamics, domain wall
dynamics, spin current, and microwave imaging. We also discuss spin
rectification in ferromagnetic semiconductors. The paper concludes with both
historical and future perspectives, by summarizing and comparing three
generations of FMR spectroscopy which have been developed for studying
magnetization dynamics.",1605.00710v2
2019-12-16,Dynamics of reconfigurable artificial spin ice: towards magnonic functional materials,"Over the past few years, the study of magnetization dynamics in artificial
spin ices has become a vibrant field of study. Artificial spin ices are
ensembles of geometrically arranged, interacting magnetic nanoislands, which
display frustration by design. These were initially created to mimic the
behavior in rare earth pyrochlore materials and to study emergent behavior and
frustration using two-dimensional magnetic measurement techniques. Recently, it
has become clear that it is possible to create artificial spin ices, which can
potentially be used as functional materials. In this Perspective, we review the
resonant behavior of spin ices (which is in the GHz frequency range), focusing
on their potential application as magnonic crystals. In magnonic crystals, spin
waves are functionalized for logic applications by means of band structure
engineering. While it has been established that artificial spin ices can
possess rich mode spectra, the applicability of spin ices to create magnonic
crystals hinges upon their reconfigurability. Consequently, we describe recent
work aiming to develop techniques and create geometries allowing full
reconfigurability of the spin ice magnetic state. We also discuss experimental,
theoretical, and numerical methods for determining the spectral response of
artificial spin ices, and give an outlook on new directions for reconfigurable
spin ices.",1912.07280v2
2021-06-12,Spin pumping and inverse spin Hall effect in CoFeB/C$_{60}$ bilayers,"Pure spin current based research is mostly focused on ferromagnet (FM)/heavy
metal (HM) system. Because of the high spin orbit coupling (SOC) these HMs
exhibit short spin diffusion length and therefore possess challenges for device
application. Low SOC (elements of light weight) and large spin diffusion length
make the organic semiconductors (OSCs) suitable for future spintronic
applications. From theoretical model it is explained that, due to $\pi$ -
$\sigma$ hybridization the curvature of the C$_{60}$ molecules may increase the
SOC strength. Here, we have investigated spin pumping and inverse spin hall
effect (ISHE) in CoFeB/C$_{60}$ bilayer system using coplanar wave guide based
ferromagnetic resonance (CPW-FMR) set-up. We have performed angle dependent
ISHE measurement to disentangle the spin rectification effects for example
anisotropic magnetoresistance, anomalous Hall effect etc. Further, effective
spin mixing conductance (g$_{eff}^{\uparrow\downarrow}$) and spin Hall angle
($\theta_{SH}$) for C$_{60}$ have been reported here. The evaluated value for
$\theta_{SH}$ is 0.055.",2106.06829v2
2016-08-24,Dynamic Stimulation of Superconductivity With Resonant Terahertz Ultrasonic Waves,"An experiment is proposed to stimulate a superconducting thin film with
terahertz (THz) acoustic waves, which is a regime not previously tested. For a
thin film on a piezoelectric substrate, this can be achieved by coupling the
substrate to a tunable coherent THz electromagnetic source. Suggested materials
for initial tests are a niobium film on a quartz substrate, with a BSCCO
intrinsic Josephson junction (IJJ) stack. This will create acoustic standing
waves on the nm scale in the thin film. A properly tuned standing wave will
enable electron diffraction across the Fermi surface, leading to electron
localization perpendicular to the substrate. This is expected to reduce the
effective dimensionality, and enhance the tendency for superconducting order
parallel to the substrate, even well above the superconducting critical
temperature. This enhancement can be observed by measuring the in-plane
critical current and the perpendicular tunneling gap. A similar experiment may
be carried out for a cuprate thin film, although the conduction electrons might
be more responsive to spin waves than to acoustic waves. These experiments
address a novel regime of large momentum transfer to the electrons, which
should be quite distinct from the more traditional regime of large energy
transfer obtained from direct electromagnetic stimulation. The experiments are
also motivated in part by novel theories of the superconducting state involving
dynamic charge-density waves and spin-density waves. Potential device
applications are discussed.",1609.02003v1
2016-02-24,Eddy-current effects on ferromagnetic resonance: Spin wave excitations and microwave screening effects,"We investigate how controlling induced eddy currents in thin film
ferromagnet-normal metal (FM/NM) structures can be used to tailor the local
microwave (MW) fields in ferromagnetic resonance (FMR) experiments. The MW
fields produced by eddy currents will in general have a relative phase shift
with respect to the applied MW field which depends on the sample geometry. The
induced fields can thus partially compensate the applied MW field, effectively
screening the FM in selected parts of the sample. The highly localized fields
produced by eddy currents enable the excitation of spin wave modes with
non-zero wave vectors, in contrast to the uniform k = 0 mode normally excited
in FMR experiments. We find that the orientation of the applied MW field is one
of the key parameters controlling the eddy-current effects. The induced
currents are maximized when the applied MW field is oriented perpendicular to
the sample plane. Increasing the magnitude of the eddy currents results in a
stronger induced MW field, enabling a more effective screening of the applied
MW field as well as an enhanced excitation of spin wave modes. This
investigation underlines that eddy currents can be used to control the
magnitude and phase of the local MW fields in thin film structures.",1602.07463v2
2001-10-25,Electromagnetic transition form factors and dilepton decay rates of nucleon resonances,"Relativistic, kinematically complete phenomenological expressions for the
dilepton decay rates of nucleon resonances with arbitrary spin and parity are
derived in terms of the magnetic, electric, and Coulomb transition form
factors. The dilepton decay rates of the nucleon resonances with masses below 2
GeV are estimated using the extended vector meson dominance model for the
transition form factors. The model provides a unified description of the photo-
and electroproduction data, the vector meson decays, and the dilepton decays of
the nucleon resonances. The constraints on the transition form factors from the
quark counting rules are taken into account. The parameters of the model are
fixed by fitting the available photo- and electroproduction data and using
results of the multichannel partial-wave analysis of the $\pi N$ scattering.
Where experimental data are not available, predictions of the non-relativistic
quark models are used as an input. The vector meson coupling constants of the
magnetic, electric, and Coulomb types are determined. The dilepton widths and
the dilepton spectra from decays of nucleon resonances with masses below 2 GeV
are calculated.",0110066v2
2020-07-13,Spin-orbit coupled depairing of a dipolar biexciton superfluid,"We consider quantum phase transitions in a system of bright dipolar excitons
which can form bound pairs (dipolar biexcitons). We assume a narrow resonance
in the interaction of excitons with opposite spins. At sufficiently large
density a resonant exciton superfluid transforms into a superfluid of
biexcitons. The transition may be either of the first or the second kind. The
average relative momenta of excitons in the pairs being beyond the light cone,
the transition should be accompanied by reduction of the photoluminescence
intensity. Effective magnetic fields due to the long-range exchange splitting
of non-radiative exciton states induce broadening of the biexciton resonance.
The fields shift the position of the gap in the elementary excitation spectrum
to a circle of degenerate minima in the k-space. Closing the new gap defines a
second order phase transition into a mixture of counter-propagating plane-wave
excitonic condensates polarized linearly in the direction perpendicular to
their wavevectors. In the resonance energy vs density phase diagram the novel
phase intervenes between the dark biexciton and radiative exciton superfluids.
We conclude that formation of a BCS-like biexciton condensate induces
correlated alignment of the effective magnetic fields and excitonic spins. We
outline important differences of the emergent mechanism from the phenomenon of
spin-orbit (SO) coupled Bose-Einstein condensation. We expect existence of
analogous mechanisms in SO-coupled fermionic superfluids and superconductors.",2007.06474v2
2019-03-27,Theory of standing spin waves in finite-size chiral spin soliton lattice,"We present a theory of standing spin wave (SSW) in a monoaxial chiral
helimagnet. Motivated by experimental findings on the magnetic field-dependence
of the resonance frequency in thin films of Cr${}$Nb$_{3} $S${}_{6}$[Goncalves
et al., Phys. Rev. B95, 104415 (2017)], we examine the SSW over a chiral
soliton lattice (CSL) excited by an ac magnetic field applied parallel and
perpendicular to the chiral axis. For this purpose, we generalize Kittel-Pincus
theories of the SSW in ferromagnetic thin films to the case of non-collinear
helimagnet with the surface end spins which are softly pinned by an anisotropy
field. Consequently, we found there appear two types of modes. One is a Pincus
mode which is composed of a long-period Bloch wave and a short-period ripple
originated from the periodic structure of the CSL. Another is a short-period
Kittel ripple excited by space-periodic perturbation which exists only in the
case where the ac field is applied perpendicular the chiral axis. We
demonstrate that the existence of the Pincus mode and the Kittel ripple is
consistent with experimentally found double resonance profile.",1903.11675v1
2004-08-03,From incommensurate to dispersive spin-fluctuations: The high-energy inelastic spectrum in superconducting YBa2Cu3O6.5,"We have investigated the spin fluctuations at energy transfers up to ~110
meV, well above the resonance energy (33 meV) in the YBa2Cu3O6.5 ortho-II
superconductor using neutron time-of-flight and triple-axis techniques. The
spectrum at high energies differs from the low-energy incommensurate
modulations previously reported where the incommensurate wave vector is largely
independent of energy. Well above the resonance the peak of the spin response
lies at wave vectors that increase with energy. Within error the excitations at
all energies above the resonance are best described by a ring around the (pi,
pi) position. The isotropic wave-vector pattern differs from a recently
reported square pattern in different but related systems. The spin spectral
weight at high-energies is similar to that in the insulator but the
characteristic velocity is ~40% lower. We introduce a method of extracting the
acoustic and optic weights at all energies from time-of-flight data. We find
that the optic spectral weight extends to surprisingly low-energies of ~25 meV,
and infer that the bilayer spin correlations weaken with increase in hole
doping. When the low-energy optic excitations are taken into account we measure
the total integrated weight around (pi, pi), for energies below 120 meV, to
agree with that expected from the insulator. As a qualitative guide, we compare
spin-wave calculations for an ordered and a disordered stripe model and
describe the inadequacy of this and other stripe models for the high-energy
fluctuations.",0408071v2
2004-09-21,"Electrodynamical properties of a ""grid"" volume resonator for travelling wave tube and backward wave oscillator","The electrodynamical properties of a volume resonator formed by a perodic
structure built from the metallic threads inside a rectangular waveguide
(""grid"" volume resonator) is considered for travelling wave tube and backward
wave oscillator operation. Peculiarities of passing of electromagnetic waves
with different polarizations through such volume resonator are discussed.",0409107v2
2004-03-30,"Effective interactions, Fermi-Bose duality, and ground states of ultracold atomic vapors in tight de Broglie waveguides","Derivation of effective zero-range one-dimensional (1D) interactions between
atoms in tight waveguides is reviewed, as is the Fermi-Bose mapping method for
determination of exact and strongly-correlated states of ultracold bosonic and
fermionic atomic vapors in such waveguides, including spin degrees of freedom.
Odd-wave 1D interactions derived from 3D p-wave scattering are included as well
as the usual even-wave interactions derived from 3D s-wave scattering, with
emphasis on the role of 3D Feshbach resonances for selectively enhancing s-wave
or p-wave interactions. A duality between 1D fermions and bosons with
zero-range interactions suggested by Cheon and Shigehara is shown to hold for
the effective 1D dynamics of a spinor Fermi gas with both even and odd-wave
interactions and that of a spinor Bose gas with even and odd-wave interactions,
with even(odd)-wave Bose coupling constants inversely related to odd(even)-wave
Fermi coupling constants. Some recent applications of Fermi-Bose mapping to
determination of many-body ground states of Bose gases and of both magnetically
trapped, spin-aligned and optically trapped, spin-free Fermi gases are
described, and a new generalized Fermi-Bose mapping is used to determine the
phase diagram of ground-state total spin of the spinor Fermi gas as a function
of the even and odd-wave coupling constants.",0403721v1
2015-11-24,Multivariate quantum memory as controllable delayed multiport beamsplitter,"The addressability of parallel spatially multimode quantum memory for light
allows one to control independent collective spin waves within the same cold
atomic ensemble. Generally speaking, there are transverse and longitudinal
degrees of freedom of the memory that one can address by a proper choice of the
pump (control) field spatial pattern. Here we concentrate on the mutual
evolution and transformation of quantum states of the longitudinal modes of
collective spin coherence in the cavity-based memory scheme. We assume that
these modes are coherently controlled by the pump waves of the on--demand
transverse profile, that is, by the superpositions of waves propagating in the
directions, close to orthogonal to the cavity axis. By the write-in, this
allows one to couple a time sequence of the incoming quantized signals to a
given set of superpositions of orthogonal spin waves. By the readout, one can
retrieve quantum states of the collective spin waves that are controllable
superpositions of the initial ones and are on demand coupled to the output
signal sequence. In general case, the memory is able to operate as a
controllable delayed multi-port beamsplitter, capable of transformation of the
delays, the durations and time shapes of signals in the sequence.
  We elaborate the theory of such light--matter interface for the spatially
multivariate cavity-based off--resonant Raman--type quantum memory. Since in
order to speed up the manipulation of complex signals in multivariate memories
it might be of interest to store relatively short light pulses of a given time
shape, we also address some issues of the cavity-based memory operation beyond
the bad cavity limit.",1511.07787v1
2024-02-06,Spin-density-wave transition in double-layer nickelate La3Ni2O7,"Recently, a signature of high-temperature superconductivity above the liquid
nitrogen temperature (77 K) was reported for La3Ni2O7 under pressure. This
finding immediately stimulates intense interest in the possible high-Tc
superconducting mechanism in double-layer nickelates. Interestingly, the
pressure-dependent phase diagram inferred from transport measurements indicates
that superconductivity under high pressure emerges from the suppression of a
density-wave-like transition at ambient pressure, which is similar to
high-temperature superconductors. Therefore, clarifying the exact nature of the
density-wave-like transition is important for determining the mechanism of
superconductivity in double-layer nickelates. Here, nuclear magnetic resonance
(NMR) spectroscopy of 139La nuclei was performed to study the density-wave-like
transition in a single crystal of La3Ni2O7. The temperature-dependent 139La NMR
spectrum and nuclear spin-lattice relaxation rate (1/T1) provide unambiguous
evidence for a spin-density-wave (SDW) transition with a transition temperature
TSDW of ~ 150 K. Furthermore, the anisotropic splitting of the NMR spectrum
suggests a possible double spin stripe with magnetic moments along the c axis.
In addition, the present NMR measurements also revealed spatial inhomogeneity
of magnetism due to inner apical oxygen vacancies. All these results will be
helpful for building a connection between superconductivity and magnetic
interactions in double-layer nickelates.",2402.03952v1
2017-04-01,Interpretation of the newly observed $Ω_c^0$ resonances,"We study the charmed and bottomed doubly strange baryons within the
heavy-quark-light-diquark framework. The two strange quarks are assumed to lie
in $S$ wave and thus their total spin is 1. We calculate the mass spectra of
the $S$ and $P$ wave orbitally excited states and find the $\Omega_c^0 (2695)$
and $\Omega_c^0 (2770)$ fit well as the $S$ wave states of charmed doubly
strange baryons. The five newly $\Omega_c^0(X)$ resonances observed by the LHCb
Collaboration, i.e. $\Omega_c^0(3000)$, $\Omega_c^0(3050)$, $\Omega_c^0(3066)$,
$\Omega_c^0(3090)$, and $\Omega_c^0(3119)$, can be interpreted as the $P$ wave
orbitally excited states. In heavy quark effective theory, we analyze their
decays into the $\Xi^+_c K^-$ and $\Xi_c'^+ K^-$, and point out that decays of
the five P-wave $\Omega_c^0$ states into the $\Xi_c^+ K^-$ and $\Xi_c'^+K^-$
are suppressed by either heavy quark symmetry or phase space. The narrowness of
the five newly observed $\Omega_c^0(X)$ states can then be naturally
interpreted with heavy quark symmetry.",1704.00179v2
2021-05-11,On the connection between magnetic interactions and the spin-wave gap of the insulating phase of NaOsO$_{3}$,"The scenario of a metal-insulator transition driven by the onset of
antiferromagnetic order in NaOsO$_3$ calls for a trustworthy derivation of the
underlying effective spin Hamiltonian. To determine the latter we rely on {\it
ab initio} electronic-structure calculations, linear spin-wave theory, and
comparison to experimental data of the corresponding magnon spectrum. We arrive
this way to Heisenberg couplings that are $\lesssim$45\% to$\lesssim$63\%
smaller than values presently proposed in the literature and
Dzyaloshinskii-Moriya interactions in the region of 15\% of the Heisenberg
exchange $J$. These couplings together with the symmetric anisotropic exchange
interaction and single-ion magnetocrystalline anisotropy successfully reproduce
the magnon dispersion obtained by resonant inelastic X-ray scattering
measurements. In particular, the spin-wave gap fully agrees with the measured
one. We find that the spin-wave gap is defined from a subtle interplay between
the single-ion anisotropy, the Dzyaloshinskii-Moriya exchange and the symmetric
anisotropic exchange interactions. The results reported here underpin the
local-moment description of NaOsO$_3$, when it comes to analyzing the magnetic
excitation spectra. Interestingly, this comes about from a microscopic theory
that describes the electron system as Bloch states, adjusted to a mean-field
solution to Hubbard-like interactions.",2105.04893v2
2022-09-21,Performance enhancement of a spin-wave-based reservoir computing system utilizing different physical conditions,"The authors have numerically studied how to enhance reservoir computing
performance by thoroughly extracting their spin-wave device potential for
higher-dimensional information generation. The reservoir device has a 1-input
exciter and 120-output detectors on the top of a continuous magnetic garnet
film for spin-wave transmission. For various nonlinear and fading-memory
dynamic phenomena distributing in the film space, small in-plane magnetic
fields were used to prepare stripe domain structures and various damping
constants at the film sides and bottom were explored. The ferromagnetic
resonant frequency and relaxation time of spin precession clearly characterized
the change in spin dynamics with the magnetic field and damping constant. The
common input signal for reservoir computing was a 1 GHz cosine wave with random
6-valued amplitude modulation. A basic 120-dimensional reservoir output vector
was obtained from time-series signals at the 120 output detectors under each of
the three magnetic field conditions. Then, 240- and 360-dimensional reservoir
output vectors were also constructed by concatenating two and three basic ones,
respectively. In nonlinear autoregressive moving average (NARMA) prediction
tasks, the computational performance was enhanced as the dimension of the
reservoir output vector becomes higher and a significantly low prediction error
was achieved for the 10th-order NARMA using the 360-dimensional vector and
optimum damping constant. The results are clear evidence that the collection of
diverse output signals efficiently increases the dimensionality effective for
reservoir computing, i.e., reservoir-state richness. This paper demonstrates
that performance enhancement through various configuration settings is a
practical approach for on-chip reservoir computing devices with small numbers
of real output nodes.",2209.10123v1
2017-08-24,Hierarchy of exchange interactions in the triangular-lattice spin-liquid YbMgGaO$_{4}$,"The spin-1/2 triangular lattice antiferromagnet YbMgGaO$_{4}$ has attracted
recent attention as a quantum spin-liquid candidate with the possible presence
of off-diagonal anisotropic exchange interactions induced by spin-orbit
coupling. Whether a quantum spin-liquid is stabilized or not depends on the
interplay of various exchange interactions with chemical disorder that is
inherent to the layered structure of the compound. We combine time-domain
terahertz spectroscopy and inelastic neutron scattering measurements in the
field polarized state of YbMgGaO$_{4}$ to obtain better microscopic insights on
its exchange interactions. Terahertz spectroscopy in this fashion functions as
high-field electron spin resonance and probes the spin-wave excitations at the
Brillouin zone center, ideally complementing neutron scattering. A global
spin-wave fit to all our spectroscopic data at fields over 4T, informed by the
analysis of the terahertz spectroscopy linewidths, yields stringent constraints
on $g$-factors and exchange interactions. Our results paint YbMgGaO$_{4}$ as an
easy-plane XXZ antiferromagnet with the combined and necessary presence of
sub-leading next-nearest neighbor and weak anisotropic off-diagonal
nearest-neighbor interactions. Moreover, the obtained $g$-factors are
substantially different from previous reports. This works establishes the
hierarchy of exchange interactions in YbMgGaO$_{4}$ from high-field data alone
and thus strongly constrains possible mechanisms responsible for the observed
spin-liquid phenomenology.",1708.07503v3
2008-09-22,Entanglement Resonance in Driven Spin Chains,"We consider a spin-1/2 anisotropic XY model with time-dependent spin-spin
coupling as means of creating long-distance entanglement. We predict the
emergence of significant entanglement between the first and the last spin
whenever the ac part of the coupling has a frequency matching the Zeeman
splitting. In particular, we find that the concurrence assumes its maximum with
a vanishing dc part. Mapping the time-dependent Hamiltonian within a
rotating-wave approximation to an effective static model provides qualitative
and quantitative understanding of this entanglement resonance. Numerical
results for the duration of the entanglement creation and its length dependence
substantiate the effective static picture.",0809.3712v2
2014-02-24,Spin-dependent recombination involving oxygen-vacancy complexes in silicon,"Spin-dependent relaxation and recombination processes in $\gamma$-irradiated
$n$-type Czochralski-grown silicon are studied using continuous wave (cw) and
pulsed electrically detected magnetic resonance (EDMR). Two processes involving
the SL1 center, the neutral excited triplet state of the oxygen-vacancy
complex, are observed which can be separated by their different dynamics. One
of the processes is the relaxation of the excited SL1 state to the ground state
of the oxygen-vacancy complex, the other a charge transfer between $^{31}$P
donors and SL1 centers forming close pairs, as indicated by electrically
detected electron double resonance. For both processes, the recombination
dynamics are studied with pulsed EDMR techniques. We demonstrate the
feasibility of true zero-field cw and pulsed EDMR for spin 1 systems and use
this to measure the lifetimes of the different spin states of SL1 also at
vanishing external magnetic field.",1402.5957v2
2017-10-31,Nuclear Magnetic Resonance in High Magnetic Field: Application to Condensed Matter Physics,"In this review, we describe the potentialities offered by the nuclear
magnetic resonance (NMR) technique to explore at a microscopic level new
quantum states of condensed matter induced by high magnetic fields. We focus on
experiments realised in resistive (up to 34~T) or hybrid (up to 45~T) magnets,
which open a large access to these quantum phase transitions. After an
introduction on NMR observable, we consider several topics: quantum spin
systems (spin-Peierls transition, spin ladders, spin nematic phases,
magnetisation plateaus and Bose-Einstein condensation of triplet excitations),
the field-induced charge density wave (CDW) in high $T_c$~superconductors, and
exotic superconductivity including the Fulde-Ferrel-Larkin-Ovchinnikov
superconducting state and the field-induced superconductivity due to the
Jaccarino-Peter mechanism.",1711.00033v2
2017-06-13,Asymmetric splitting of an antiferromagnetic resonance via quartic exchange interactions in multiferroic hexagonal HoMnO$_3$,"The symmetric splitting of two spin-wave branches in an antiferromagnetic
resonance (AFR) experiment has been an essential measurement of
antiferromagnets for over half a century. In this work, circularly polarized
time-domain THz spectroscopy experiments performed on the low symmetry
multiferroic h-HoMnO$_3$ reveal an AFR of the Mn sublattice to split
asymmetrically in applied magnetic field, with an $\approx$ 50\% difference in
$g$-factors between the high and low energy branches of this excitation. The
temperature dependence of the $g$-factors, including a drastic renormalization
at the Ho spin ordering temperature, reveals this asymmetry to unambiguously
stem from Ho-Mn interactions. Theoretical calculations demonstrate the AFR
asymmetry is not explained by conventional Ho-Mn exchange mechanisms alone and
are only reproduced if quartic spin interactions are also included in the spin
Hamiltonian. Our results provide a paradigm for the optical study of such novel
interactions in hexagonal manganites and low symmetry antiferromagnets in
general.",1706.04141v2
2023-12-11,Stroboscopic X-ray Diffraction Microscopy of Dynamic Strain in Diamond Thin-film Bulk Acoustic Resonators for Quantum Control of Nitrogen Vacancy Centers,"Bulk-mode acoustic waves in a crystalline material exert lattice strain
through the thickness of the sample, which couples to the spin Hamiltonian of
defect-based qubits such as the nitrogen-vacancy (NV) center defect in diamond.
This mechanism has been previously harnessed for unconventional quantum spin
control, spin decoherence protection, and quantum sensing. Bulk-mode acoustic
wave devices are also important in the microelectronics industry as microwave
filters. A key challenge in both applications is a lack of appropriate operando
microscopy tools for quantifying and visualizing gigahertz-frequency dynamic
strain. In this work, we directly image acoustic strain within NV
center-coupled diamond thin-film bulk acoustic wave resonators using
stroboscopic scanning hard X-ray diffraction microscopy at the Advanced Photon
Source. The far-field scattering patterns of the nano-focused X-ray diffraction
encode strain information entirely through the illuminated thickness of the
resonator. These patterns have a real-space spatial variation that is
consistent with the bulk strain's expected modal distribution and a
momentum-space angular variation from which the strain amplitude can be
quantitatively deduced. We also perform optical measurements of strain-driven
Rabi precession of the NV center spin ensemble, providing an additional
quantitative measurement of the strain amplitude. As a result, we directly
measure the NV spin-stress coupling parameter $b = 2.73(2)$ MHz/GPa by
correlating these measurements at the same spatial position and applied
microwave power. Our results demonstrate a unique technique for directly
imaging AC lattice strain in micromechanical structures and provide a direct
measurement of a fundamental constant for the NV center defect spin
Hamiltonian.",2312.06862v1
2003-07-01,Observation of extended scattering continua characteristic of spin fractionalization in the 2D frustrated quantum magnet Cs2CuCl4 by neutron scattering,"The magnetic excitations of the quasi-2D spin-1/2 Heisenberg antiferromagnet
on an anisotropic triangular lattice Cs2CuCl4 are explored throughout the 2D
Brillouin zone using inelastic neutron scattering. In the spin liquid phase
above the transition to magnetic order extended excitation continua are
observed, characteristic of fractionalization of S=1 spin waves into pairs of
deconfined S=1/2 spinons and the hallmark of a resonating-valence-bond (RVB)
state. The weak inter-layer couplings stabilize incommensurate spiral order at
low temperatures and in this phase sharp magnons carrying a small part of the
total scattering weight are observed at low energies below the continuum lower
boundary. Linear spin-wave theory including one- and two-magnon processes can
describe the sharp magnon excitation, but not the dominant continuum
scattering, which instead is well described by a parameterized two-spinon
cross-section. Those results suggest a cross-over in the nature of excitations
from S=1 spin waves at low energies to S=1/2 spinons at medium to high
energies, which could be understood if Cs2CuCl4 was in the close proximity of a
transition between a fractional spin liquid and a magnetically-ordered phase.",0307025v1
2016-09-27,Identical Spin Rotation Effect and Electron Spin Waves in Quantum Gas of Atomic Hydrogen,"We present an experimental study of electron spin waves in atomic hydrogen
gas compressed to high densities of $\sim 5 \times 10^{18}$ cm$^{-3}$ at
temperatures ranging from 0.26 to 0.6 K in strong magnetic field of 4.6 T.
Hydrogen gas is in a quantum regime when the thermal de Broglie wavelength is
much larger than the s-wave scattering length. In this regime the identical
particle effects play major role in atomic collisions and lead to the Identical
Spin Rotation effect (ISR). We observed a variety of spin wave modes caused by
this effect with strong dependence on the magnetic potential caused by
variations of the polarizing magnetic field. We demonstrate confinement of the
ISR modes in the magnetic potential and manipulate their properties by changing
the spatial profile of magnetic field. We have found that at a high enough
density of H gas the magnons accumulate in their ground state in the magnetic
trap and exhibit long coherence, which has a profound effect on the electron
spin resonance spectra. Such macroscopic accumulation of the ground state
occurs at a certain critical density of hydrogen gas, where the chemical
potential of the magnons becomes equal to the energy of their ground state in
the trapping potential.",1609.08432v2
2016-12-30,High-temperature charge density wave correlations in La$_{1.875}$Ba$_{0.125}$CuO$_{4}$ without spin-charge locking,"Although all superconducting cuprates display charge-ordering tendencies,
their low-temperature properties are distinct, impeding efforts to understand
the phenomena within a single conceptual framework. While some systems exhibit
stripes of charge and spin, with a locked periodicity, others host charge
density waves (CDWs) without any obviously related spin order. Here we use
resonant inelastic x-ray scattering (RIXS) to follow the evolution of charge
correlations in the canonical stripe ordered cuprate
La$_{1.875}$Ba$_{0.125}$CuO$_{4}$ (LBCO~$1/8$) across its ordering transition.
We find that high-temperature charge correlations are unlocked from the
wavevector of the spin correlations, signaling analogies to CDW phases in
various other cuprates. This indicates that stripe order at low temperatures is
stabilized by the coupling of otherwise independent charge and spin density
waves, with important implications for the relation between charge and spin
correlations in the cuprates.",1701.00022v5
2021-12-11,Anisotropic long-range spin transport in canted antiferromagnetic orthoferrite YFeO$_3$,"In antiferromagnets, the efficient propagation of spin-waves has until now
only been observed in the insulating antiferromagnet hematite, where circularly
(or a superposition of pairs of linearly) polarized spin-waves propagate over
long distances. Here, we report long-distance spin-transport in the
antiferromagnetic orthoferrite YFeO$_3$, where a different transport mechanism
is enabled by the combined presence of the Dzyaloshinskii-Moriya interaction
and externally applied fields. The magnon decay length is shown to exceed
hundreds of nano-meters, in line with resonance measurements that highlight the
low magnetic damping. We observe a strong anisotropy in the magnon decay
lengths that we can attribute to the role of the magnon group velocity in the
propagation of spin-waves in antiferromagnets. This unique mode of transport
identified in YFeO$_3$ opens up the possibility of a large and technologically
relevant class of materials, i.e., canted antiferromagnets, for long-distance
spin transport.",2112.05947v1
2005-12-15,Ferromagnetic Resonance Linewidths in Ultrathin Structures: Theoretical Studies of Spin Pumping,"We present theoretical studies of the spin pumping contribution to the
ferromagnetic resonance linewidth for various ultrathin film ferromagnetic
structures. We consider the isolated film on a substrate, with Fe on Au(100)
and Fe on W(110) as examples. We explore as well the linewidth from this
mechanism for the optical and acoustical collective modes of FM/Cu$_{\rm
N}$/FM/Cu(100) structures. The calculations employ a realistic electronic
structure, with self consistent ground states generated from the empirical
tight binding method, with nine bands for each material in the structure. The
spin excitations are generated through use of the random phase approximation
applied to the system, including the semi infinite substrate on which the
structure is grown. We calculate the frequency response of the system directly
by examining the spectral density associated with collective modes whose wave
vector parallel to the surface is zero. Linewidths with origin in leakage of
spin angular momentum from the adsorbed structure to the semi infinite
substrate may be extracted from these results. We discuss a number of issues,
including the relationship between the interfilm coupling calculated
adiabatically for trilayers, and that extracted from the (dynamical) spin wave
spectrum. We obtain excellent agreement with experimental data, within the
framework of calculations with no adjustable parameters.",0512333v1
2002-02-11,Radiation Induced Landau-Lifshitz-Gilbert Damping in Ferromagnets,"The Landau-Lifshitz-Gilbert damping coefficient employed in the analysis of
spin wave ferromagnetic resonance is related to the electrical conductivity of
the sample. The changing magnetization (with time) radiates electromagnetic
fields. The electromagnetic energy is then absorbed by the sample and the
resulting heating effect describes magnetic dissipative damping. The
ferromagnetic resonance relaxation rate theoretically depends on the geometry
(shape and size) of the sample as well as temperature in agreement with
experiment.",0202181v1
2004-11-16,Resonant spin-dependent electron coupling in a III-V/II-VI heterovalent double quantum well,"We report on design, fabrication, and magnetooptical studies of a III-V/II-VI
hybrid structure containing a GaAs/AlGaAs/ZnSe/ZnCdMnSe double quantum well
(QW). The structure design allows one to tune the QW levels into the resonance,
thus facilitating penetration of the electron wave function from the diluted
magnetic semiconductor ZnCdMnSe QW into the nonmagnetic GaAs QW and vice versa.
Magneto-photoluminescence studies demonstrate level anticrossing and strong
intermixing resulting in a drastic renormalization of the electron effective g
factor, in perfect agreement with the energy level calculations.",0411409v1
2005-03-04,Double dispersion of the magnetic resonant mode in cuprates,"The magnetic excitation spectra in the vicinity of the resonant peak, as
observed by inelastic neutron scattering in cuprates, are studied within the
memory-function approach. It is shown that at intermediate doping the
superconducting gap induces a double dispersion of the peak, with an anisotropy
rotated between the downward and upward branch. Similar behavior, but with a
spin-wave dispersion at higher energies, is obtained for the low-doping case
assuming a large pairing pseudogap.",0503099v1
2006-03-28,Pairing of a harmonically trapped fermionic Tonks-Girardeau gas,"The fermionic Tonks-Girardeau (FTG) gas is a one-dimensional spin-polarized
Fermi gas with infinitely strong attractive zero-range odd-wave interactions,
arising from a confinement-induced resonance reachable via a three-dimensional
p-wave Feshbach resonance. We investigate the off-diagonal long-range order
(ODLRO) of the FTG gas subjected to a longitudinal harmonic confinement by
analyzing the two-particle reduced density matrix for which we derive a
closed-form expression. Using a variational approach and numerical
diagonalization we find that the largest eigenvalue of the two-body density
matrix is of order N/2, where N is the total particle number, and hence a
partial ODLRO is present for a FTG gas in the trap.",0603747v1
2000-09-05,Pi Pi Scattering and Scalar Mesons in an Effective Chiral Lagrangian,"In this talk I summarize recently proposed mechanisms to understand pi pi
scattering to 1 GeV in an effective chiral Lagrangian. The Lagrangian includes
higher resonances in addition to pions consistently with the chiral symmetry.
Iso-spin zero S-wave partial wave amplitude is reproduced up till about 1.2 GeV
by including a pion self-interaction and resonant pole exchanges of rho,
f0(980) and sigma derived from the effective chiral Lagrangian. The best fit
shows that sigma has a mass of around 560 MeV and a width of about 370 MeV.",0009051v1
2003-06-25,Quasifree eta photoproduction from nuclei and medium modifications of resonances,"We investigate the sensitivity of the differential cross section, recoil
nucleon polarization and the photon asymmetry to changes in the elementary
amplitude, medium modifications of the resonance $(S_{11},D_{13})$ masses, as
well as nuclear target effects. All calculations are performed within a
relativistic plane wave impulse approximation formalism resulting in analytical
expressions for all observables. The spin observables are shown to be unique
tools to study subtle effects that are not accessible by only looking at the
unpolarized differential cross section.",0306074v1
2007-02-01,Interfacing Collective Atomic Excitations and Single Photons,"We study the performance and limitations of a coherent interface between
collective atomic states and single photons. A quantized spin-wave excitation
of an atomic sample inside an optical resonator is prepared probabilistically,
stored, and adiabatically converted on demand into a sub-Poissonian photonic
excitation of the resonator mode. The measured peak single-quantum conversion
efficiency of 0.84(11) and its dependence on various parameters are well
described by a simple model of the mode geometry and multilevel atomic
structure, pointing the way towards implementing high-performance stationary
single-photon sources.",0702013v1
2006-03-23,Generation of a squeezed vacuum resonant on Rubidium D_1 line with periodically-poled KTiOPO_4,"We report generation of a continuous-wave squeezed vacuum resonant on the Rb
D_1 line (795 nm) using periodically poled KTiOPO_4 (PPKTP) crystals. With a
frequency doubler and an optical parametric oscillator based on PPKTP crystals,
we observed a squeezing level of -2.75 +- 0.14 dB and an anti-squeezing level
of +7.00 +- 0.13 dB. This system could be utilized for demonstrating storage
and retrieval of the squeezed vacuum, which is important for the ultra-precise
measurement of atomic spins as well as quantum information processing.",0603214v1
2010-10-19,Ferromagnetic resonance with a magnetic Josephson junction,"We show experimentally and theoretically that there is a coupling via the
Aharonov-Bohm phase between the order parameter of a ferromagnet and a singlet,
s-wave, Josephson supercurrent. We have investigated the possibility of
measuring the dispersion of such spin waves by varying the magnetic field
applied in the plane of the junction and demonstrated the electromagnetic
nature of the coupling by the observation of magnetic resonance side-bands to
microwave induced Shapiro steps.",1010.3858v1
2010-12-31,Antiferromagnetic long range order in the uniform resonating valence bond state on square lattice,"With extensive variational Monte Carlo simulation, we show that the uniform
resonating valence bond state(U-RVB) on square lattice is actually
antiferromagnetic long range ordered. The ordered moment is estimated to be
$m\approx 0.17$. Finite size scaling analysis on lattice up to lattice size of
$50\times 50$ shows that the spin structure factor at the antiferromagnetic
ordering wave vector follows perfectly the $\mathrm{S}_{\mathrm{q}=(\pi,\pi)}
\simeq S_{0}+\alpha (1/L)^{5/4}$ behavior, where $L$ is linear scale of the
lattice. Such a behavior is quite unexpected from the slave Boson mean field
treatment or the Gutzwiller approximation of the uniform RVB state.",1101.0193v2
2011-09-22,Measurement of the double polarisation observable G in single pseudoscalar meson photoproduction,"The excitation spectrum of the nucleon consists of several overlapping
resonances. To identify these resonances and their contributions to the
measured cross sections, a partial wave analysis is used. A set of at least
eight, well chosen, single and double polarisation observables is needed to
derive an unambiguous solution. With the Crystal Barrel/TAPS setup at ELSA,
single and double polarisation observables can be measured in different
reaction channels, by using the combination of a linearly or circularly
polarised photon beam and a longitudinally or transversely polarised butanol
frozen spin target. Results of the G asymmetry measurement, using linearly
polarised photons and longitudinally polarised protons, for pion and eta
photoproduction are presented. This project is supported by the DFG (SFB/TR16).",1109.4813v1
2017-06-29,Magnetic Merry Go Round - Resonant Reshaping of Colloidal Clusters on a Current Carrying Wire,"We describe a simple physical method for trapping and transforming magnetic
colloid clusters on a current carrying wire. We use the wire's field as a mould
to form colloidal rings and helices on its surface. To transform the initially
amorphous, kinetically trapped, bulky clusters we induce a low frequency
magnetic modulation wave that spins around the wire axis, effectively
eliminates defects from the clusters and stretches them into slender rings and
helical structures. A qualitative theoretical model of the underlying resonant
transformations is developed and the practical potential of the wire as a
magnetic micro-assembler is discussed.",1706.09573v1
2019-07-09,Faraday patterns generated by Rabi oscillation in a binary Bose-Einstein condensate,"The interaction between atoms in a two-component Bose-Einstein condensate
(BEC) is effectively modulated by the Rabi oscillation. This periodic
modulation of the effective interaction is shown to generate Faraday patterns
through parametric resonance. We show that there are multiple resonances
arising from the density and spin waves in a two-component BEC, and investigate
the interplay between the Faraday-pattern formation and the phase separation.",1907.03945v1
2024-03-07,Cavity-assisted resonance fluorescence from a nitrogen-vacancy center in diamond,"The nitrogen-vacancy center in diamond, owing to its optically addressable
and long-lived electronic spin, is an attractive resource for the generation of
remote entangled states. However, the center's low native fraction of coherent
photon emission, $\sim$3\%, strongly reduces the achievable spin-photon
entanglement rates. Here, we couple a nitrogen-vacancy center with a narrow
extrinsically broadened linewidth (\unit[159]{MHz}), hosted in a micron-thin
membrane, to the mode of an open optical microcavity. The resulting Purcell
factor of $\sim$1.8 increases the fraction of zero-phonon line photons to above
44\%, leading to coherent photon emission rates exceeding four times the state
of the art under non-resonant excitation. Bolstered by the enhancement provided
by the cavity, we for the first time measure resonance fluorescence without any
temporal filtering with $>$10 signal-to-laser background ratio. Our microcavity
platform would increase spin-spin entanglement success probabilities by more
than an order of magnitude compared to existing implementations. Selective
enhancement of the center's zero-phonon transitions could furthermore unlock
efficient application of quantum optics techniques such as wave-packet shaping
or all-optical spin manipulation.",2403.04611v1
2018-04-29,Probing spin-phonon interactions in silicon carbide with Gaussian acoustics,"Hybrid spin-mechanical systems provide a platform for integrating quantum
registers and transducers. Efficient creation and control of such systems
require a comprehensive understanding of the individual spin and mechanical
components as well as their mutual interactions. Point defects in silicon
carbide (SiC) offer long-lived, optically addressable spin registers in a
wafer-scale material with low acoustic losses, making them natural candidates
for integration with high quality factor mechanical resonators. Here, we show
Gaussian focusing of a surface acoustic wave in SiC, characterized by a novel
stroboscopic X-ray diffraction imaging technique, which delivers direct, strain
amplitude information at nanoscale spatial resolution. Using ab initio
calculations, we provide a more complete picture of spin-strain coupling for
various defects in SiC with C3v symmetry. This reveals the importance of shear
for future device engineering and enhanced spin-mechanical coupling. We
demonstrate all-optical detection of acoustic paramagnetic resonance without
microwave magnetic fields, relevant to sensing applications. Finally, we show
mechanically driven Autler-Townes splittings and magnetically forbidden Rabi
oscillations. These results offer a basis for full strain control of
three-level spin systems.",1804.10996v2
1999-07-21,Wave-vector dependence of spin and density multipole excitations in quantum dots,"We have employed time-dependent local-spin density functional theory to
analyze the multipole spin and charge density excitations in GaAs-AlGaAs
quantum dots. The on-plane transferred momentum degree of freedom has been
taken into account, and the wave-vector dependence of the excitations is
discussed. In agreement with previous experiments, we have found that the
energies of these modes do not depend on the transferred wave-vector, although
their intensities do. Comparison with a recent resonant Raman scattering
experiment [C. Sch\""uller et al, Phys. Rev. Lett {\bf 80}, 2673 (1998)] is
made. This allows to identify the angular momentum of several of the observed
modes as well as to reproduce their energies.",9907321v1
2001-10-17,Magnetic field tuning of charge and spin order in the cuprate superconductors,"Recent neutron scattering, nuclear magnetic resonance, and scanning tunneling
microscopy experiments have yielded valuable new information on the interplay
between charge and spin density wave order and superconductivity in the cuprate
superconductors, by using an applied perpendicular magnetic field to tune the
ground state properties. We compare the results of these experiments with the
predictions of a theory which assumed that the ordinary superconductor was
proximate to a quantum transition to a superconductor with co-existing
spin/charge density wave order.",0110329v3
2005-11-21,Quantum melting of the hole crystal in the spin ladder of Sr14-xCaxCu24O41,"The ""spin ladder"" is a reduced-dimensional analogue of the high temperature
superconductors that was predicted to exhibit both superconductivity and an
electronic charge density wave or ""hole crystal"" (HC). Both phenomena have been
observed in the doped spin ladder system Sr14-xCaxCu24O41 (SCCO), which at x=0
exhibits a HC which is commensurate at all temperatures. To investigate the
effects of discommensuration we used resonant soft x-ray scattering (RSXS) to
study SCCO as a function of doped hole density, d. The HC forms only with the
commensurate wave vectors L_L = 1/5 and L_L = 1/3 and exhibits a simple
temperature scaling T_(1/3) / T_(1/5) = 5/3. For irrational wave vectors the HC
""melts"", perhaps through the motion of topological defects carrying fractional
charge.",0511524v1
2007-06-08,Optical coupling to spin waves in the cycloidal multiferroic BiFeO3,"The magnon and optical phonon spectrum of an incommensurate multiferroic such
as BiFeO3 is considered in the framework of a phenomenological Landau theory.
The resulting spin wave spectrum is quite distinct from commensurate substances
due to soft mode anisotropy and magnon zone folding. The former allows
electrical control of spin wave propagation via reorientation of the
spontaneous ferroelectric moment. The latter gives rise to multiple
magneto-dielectric resonances due to the coupling of optical phonons at zero
wavevector to magnons at integer multiples of the cycloid wavevector. These
results show that the optical response of a multiferroic reveals much more
about its magnetic excitations than previously anticipated on the basis of
simpler models.",0706.1260v3
2010-01-12,Dynamic pinning at a Py/Co interface measured using inductive magnetometry,"Broadband FMR responses for metallic single-layer and bi-layer magnetic films
with total thicknesses smaller than the microwave magnetic skin depth have been
studied. Two different types of microwave transducers were used to excite and
detect magnetization precession: a narrow coplanar waveguide and a wide
microstrip line. Both transducers show efficient excitation of higher-order
standing spin wave modes. The ratio of amplitudes of the first standing spin
wave to the fundamental resonant mode is independent of frequency for single
films. In contrast, we find a strong variation of the amplitudes with frequency
for bi-layers and the ratio is strongly dependent on the ordering of layers
with respect to a stripline transducer. Most importantly, cavity FMR
measurements on the same samples show considerably weaker amplitudes for the
standing spin waves. All experimental data are consistent with expected effects
due to screening by eddy currents in films with thicknesses below the microwave
magnetic skin depth. Finally, conditions for observing eddy current effects in
different types of experiments are critically examined.",1001.1837v1
2016-08-31,Cavity enhanced telecom heralded single photons for spin-wave solid state quantum memories,"We report on a source of heralded narrowband (3MHz) single photons compatible
with solid-state spin-wave quantum memories based on praseodymium doped
crystals. Widely non-degenerate narrow-band photon pairs are generated using
cavity enhanced down conversion. One photon from the pair is at telecom
wavelengths and serves as heralding signal, while the heralded single photon is
at 606nm, resonant with an optical transition in Pr:YSO. The source offers a
heralding efficiency of 28% and a generation rate exceeding 2000 pairs/mW in a
single-mode. The single photon nature of the heralded field is confirmed by a
direct antibunching measurement, with a measured antibunching parameter down to
0.010(4). Moreover, we investigate in detail photon cross- and autocorrelation
functions proving non-classical correlations between the two photons. The
results presented in this paper represent significant improvement over the
state of the art and offer prospects for the demonstration of single photon
spin-wave storage in an on-demand solid state quantum memory, heralded by a
telecom photon.",1608.08943v1
2020-08-13,Comparison of measured and simulated spin-wave mode spectra of magnetic nanostructures,"Motivated by the importance of magnetization dynamics in nanomagnets for the
development and optimization of magnetic devices and sensors, we measured and
modeled spin wave spectra in patterned elliptical nanomagnets. Ferromagnetic
resonance spectra for multiple nanomagnets of Ni80Fe20 , fabricated by
electron-beam lithography to have nominal short-axes of 200 nm or 100 nm, were
measured by use of heterodyne magneto-optical microwave microscopy. Scanning
electron microscope images taken of the same nanomagnets were used to define
element shapes for micromagnetic simulations. Measured spectra show significant
differences between nominally identical nanomagnets, which could be only
partially attributed to uncontrolled shape variations in the patterning
process, as evidence by the limited agreement between the measured and
simulated spectra. Agreement between measurements and simulations was improved
by including a zone of reduced magnetization and exchange at the edges of the
nanomagnets in the simulations. Our results show that the reduction of shape
variations between individual magnetic random-access memory elements can
potentially improve their performance. However, unambiguous determination of
materials parameters in nanomagnets based on analysis and modeling of spin wave
spectra remains problematic.",2008.05662v1
2017-06-14,Broadband conversion of microwaves into propagating spin waves in patterned magnetic structures,"We have used time-resolved scanning Kerr microscopy (TRSKM) and micromagnetic
simulations to demonstrate that, when driven by spatially uniform microwave
field, the edges of patterned magnetic samples represent both efficient and
highly tunable sources of propagating spin waves. The excitation is due to the
local enhancement of the resonance frequency induced by the non-uniform dynamic
demagnetizing field generated by precessing magnetization aligned with the
edges. Our findings represent a crucial step forward in the design of nanoscale
spin-wave sources for magnonic architectures, and are also highly relevant to
the understanding and interpretation of magnetization dynamics driven by
spatially-uniform magnetic fields in patterned magnetic samples.",1706.04409v2
2020-06-01,Spin-wave spectroscopy of individual ferromagnetic nanodisks,"The increasing demand for ultrahigh data storage densities requires
development of 3D magnetic nanostructures. In this regard, focused electron
beam induced deposition (FEBID) is a technique of choice for direct-writing of
various complex nano-architectures. However, intrinsic properties of
nanomagnets are often poorly known and can hardly be assessed by local optical
probe techniques. Here, we demonstrate spatially resolved spin-wave
spectroscopy of individual circular magnetic elements with radii down to 100
nm. The key component of the setup is a microwave antenna whose microsized
central part is placed over a movable substrate with well-separated CoFe-FEBID
nanodisks. The circular symmetry of the disks gives rise to standing spin-wave
resonances and allows for the deduction of the saturation magnetization and the
exchange stiffness of the material using an analytical theory. The presented
approach is especially valuable for the characterization of direct-write
elements opening new horizons for 3D nanomagnetism and magnonics.",2006.00763v1
2021-11-22,Excitation and reception of magnetostatic surface spin waves in thin conducting ferromagnetic films by coplanar microwave antennas. Part II: Experiment,"We report on propagating spin-wave spectroscopy measurements carried out on
coplanar nano-antenna devices made from a Si/SiO$_2$/Ru(5nm)/Co(20)/Pt(5nm)
film. The measurements were analyzed in detail by employing newly developed
theoretical modeling and de-embedding procedures. The magnetic parameters of
the film were determined by complementary Brillouin light scattering and
ferromagnetic resonance measurements. The propagating spin wave signals could
be accounted for quantitatively for the range of externally applied magnetic
fields investigated in this study: 130-1500 Oe.",2111.11111v3
2022-03-09,Exchange spin waves in thin films with gradient composition,"We report investigation of ferromagnetic resonance phenomenon in
ferromagnetic thin films with essentially non-uniform composition. Epitaxial
Pd-Fe thin film with linear distribution of Fe content across the thickness is
used as the model material. Anomalous perpendicular standing spin waves are
observed and quantified using the collective dynamic equation. Numerical
analysis yields the exchange stiffness constant for diluted Pd-Fe alloy
$D=2A/\mu_0M_s=15$~T$\cdot$nm$^2$ and the ratio of the effective magnetization
to the saturation magnetization $M_{eff}/M_s=1.16$. It is demonstrated that,
overall, engineering of thin films with non-uniform composition across the
thickness can be used for high-frequency or low-field magnonic operations using
exchange spin waves.",2203.05014v1
2022-09-22,Spin wave study of magnetic perpendicular surface anisotropy in single crystalline MgO$\text{/}$Fe$\text{/}$MgO films,"Broadband ferromagnetic resonance is measured in single crystalline Fe films
of varying thickness sandwiched between MgO layers. An exhaustive magnetic
characterization of the films (exchange constant, cubic, uniaxial and surface
anisotropies) is enabled by the study of the uniform and the first
perpendicular standing spin wave modes as a function of applied magnetic field
and film thickness. Additional measurements of non-reciprocal spin wave
propagation allow us to separate each of the two interface contributions to the
total surface anisotropy. The results are consistent with the model of a
quasi-bulk film interior and two magnetically different top and bottom
interfaces, a difference ascribed to different oxidation states.",2209.10906v2
2023-11-23,Exciting high-frequency short-wavelength spin waves using high harmonics of a magnonic cavity mode,"Confined spin-wave modes are a promising object for studying nonlinear
effects and future quantum technologies. Here, using micromagnetic simulations,
we use a microwave magnetic field from a coplanar waveguide (CPW) to pump a
standing spin-wave confined in the cavity of magnonic crystal. We find that the
frequency of the fundamental cavity mode is equal to the ferromagnetic
resonance frequency of the plane film and overlaps with the magnonic bandgap,
allowing high magnetic field tunability. Multi-frequency harmonics of the
cavity mode are generated once the microwave amplitude surpasses a certain
threshold. Specifically, the second and third harmonics at 0.5 T equate to 48.6
and 72.9 GHz with wavelengths of 44 and 22 nm respectively, which propagate
into the crystal. This effect reaches saturation when the CPW covers the entire
cavity, making the system feasible for realization. These processes show
potential for the advancement of magnonics at high-frequencies and very
short-wavelengths.",2311.14143v1
2024-04-12,Nonlinear Wave-Spin Interactions in Nitrogen-Vacancy Centers,"Nonlinear phenomena represent one of the central topics in the study of
wave-matter interactions and constitute the key blocks for various applications
in optical communication, computing, sensing, and imaging. In this work, we
show that by employing the interactions between microwave photons and electron
spins of nitrogen-vacancy (NV) centers, one can realize a variety of nonlinear
effects, ranging from the resonance at the sum or difference frequency of two
or more waves to electromagnetically induced transparency from the interference
between spin transitions. We further verify the phase coherence through
two-photon Rabi-oscillation measurements. The highly sensitive, optically
detected NV-center dynamics not only provides a platform for studying
magnetically induced nonlinearities but also promises novel functionalities in
quantum control and quantum sensing.",2404.08772v1
2006-06-05,Phenomenological theory of current driven exchange switching in ferromagnetic nanojunctions,"Phenomenological approach is developed in the theory of spin-valve type
ferromagnetic junctions to describe exchange switching by current flowing
perpendicular to interfaces. Forward and backward current switching effects are
described and they may be principally different in nature. Mobile electron
spins are considered as being free in all the contacting ferromagnetic layers.
Joint action of the following two current effects is investigated: the
nonequilibrium longitudinal spin-injection effective field and the transverse
spin-transfer surface torque. Dispersion relation for fluctuations is derived
and solved for a junction model having spatially localized spin transfer
torque: depth of the torque penetration into the free layer is assumed much
smaller than the total free layer thickness. Some critical value of the well
known Gilbert damping constant is established for the first time. Spin transfer
torque dominates in the instability threshold determination for small enough
damping constants, while the spin-injection effective field dominates for high
damping. Fine interplay between spin transfer torque and spin injection is
necessary to provide a hysteretic behavior of the resistance versus current
dependence. The state diagram building up shows the possibility of
non-stationary (time dependent) nonlinear states arising due to instability
development. Calculations lead to the instability rise time values of the order
of 0.1 ns. Spin wave resonance frequency spectrum softening occurs under the
current growing to the instability threshold. Magnetization fluctuations above
the threshold rise oscillating with time for low damping, but rise
aperiodically and much more rapid for high damping.",0606102v2
2020-07-15,Electrical Control of Coherent Spin Rotation of a Single-Spin Qubit,"Nitrogen vacancy (NV) centers, optically-active atomic defects in diamond,
have attracted tremendous interest for quantum sensing, network, and computing
applications due to their excellent quantum coherence and remarkable
versatility in a real, ambient environment. One of the critical challenges to
develop NV-based quantum operation platforms results from the difficulty to
locally address the quantum spin states of individual NV spins in a scalable,
energy-efficient manner. Here, we report electrical control of the coherent
spin rotation rate of a single-spin qubit in NV-magnet based hybrid quantum
systems. By utilizing electrically generated spin currents, we are able to
achieve efficient tuning of magnetic damping and the amplitude of the dipole
fields generated by a micrometer-sized resonant magnet, enabling electrical
control of the Rabi oscillation frequency of NV spins. Our results highlight
the potential of NV centers in designing functional hybrid solid-state systems
for next-generation quantum-information technologies. The demonstrated coupling
between the NV centers and the propagating spin waves harbored by a magnetic
insulator further points to the possibility to establish macroscale
entanglement between distant spin qubits.",2007.07543v1
2011-11-17,Resonant magnetic exciton mode in the heavy-fermion antiferromagnet CeB6,"Resonant magnetic excitations are widely recognized as hallmarks of
unconventional superconductivity in copper oxides, iron pnictides, and
heavy-fermion compounds. Numerous model calculations have related these modes
to the microscopic properties of the pair wave function, but the mechanisms
underlying their formation are still debated. Here we report the discovery of a
similar resonant mode in the non-superconducting, antiferromagnetically ordered
heavy-fermion metal CeB6. Unlike conventional magnons, the mode is
non-dispersive, and its intensity is sharply concentrated around a wave vector
separate from those characterizing the antiferromagnetic order. The magnetic
intensity distribution rather suggests that the mode is associated with a
coexisting order parameter of the unusual antiferro-quadrupolar phase of CeB6,
which has long remained ""hidden"" to the neutron-scattering probes. The mode
energy increases continuously below the onset temperature for
antiferromagnetism, in parallel to the opening of a nearly isotropic spin gap
throughout the Brillouin zone. These attributes bear strong similarity to those
of the resonant modes observed in unconventional superconductors below their
critical temperatures. This unexpected commonality between the two disparate
ground states indicates the dominance of itinerant spin dynamics in the ordered
low-temperature phases of CeB6 and throws new light on the interplay between
antiferromagnetism, superconductivity, and ""hidden"" order parameters in
correlated-electron materials.",1111.4151v1
2019-09-09,Ferromagnetic resonance assisted optomechanical magnetometer,"The resonant enhancement of mechanical and optical interaction in
optomechanical cavities enables their use as extremely sensitive displacement
and force detectors. In this work we demonstrate a hybrid magnetometer that
exploits the coupling between the resonant excitation of spin waves in a
ferromagnetic insulator and the resonant excitation of the breathing mechanical
modes of a glass microsphere deposited on top. The interaction is mediated by
magnetostriction in the ferromagnetic material and the consequent mechanical
driving of the microsphere. The magnetometer response thus relies on the
spectral overlap between the ferromagnetic resonance and the mechanical modes
of the sphere, leading to a peak sensitivity better than 900 pT Hz$^{-1/2}$ at
206 MHz when the overlap is maximized. By externally tuning the ferromagnetic
resonance frequency with a static magnetic field we demonstrate sensitivity
values at resonance around a few nT Hz$^{-1/2}$ up to the GHz range. Our
results show that our hybrid system can be used to build high-speed sensor of
oscillating magnetic fields.",1909.03924v4
2023-01-30,Evolution of binary systems accompanying axion clouds in extreme mass ratio inspirals,"Superradiant instability of rotating black holes (BHs) leads to the formation
of a cloud of ultralight bosons, such as axions. When the BH with the cloud
belongs to a binary system and is in an inspiraling orbit, the resonant
transition between the axion's bound states can occur. We study the history of
the evolution of the binary system accompanying the cloud composed of the
fastest growing mode, and its impact on the observational signatures,
especially for small mass ratio cases. In this case, the hyperfine resonance,
which has a very small resonance frequency, is relevant. Therefore, due to the
long timescale, we should take into account the decaying process of axions in
the transition destination mode, the backreaction to the orbital motion and the
central BH, and gravitational emission from the cloud. We present a formulation
to examine the evolution of the system around the resonance and useful
expressions for the analysis. As a result, we found the mass of the cloud that
can remain after the resonance is, at most, about $10^{-5}$ of the central BH.
The maximum remaining cloud mass is achieved when the mass ratio of the binary
is $q\sim10^{-3}$. In addition, we show that the resonant transition hardly
changes the BH mass and spin distribution, while the associated modification of
the gravitational wave frequency evolution when the binary pass through the
resonance can be a signature of the presence of the cloud.",2301.13213v2
2008-02-28,Current driven spin-wave instability triggered by the anomalous Hall effect,"We studied the effect of strong electric current on spin waves interacting
relativistically with the current. The spin-wave spectrum is calculated at
arbitrary direction of the wave vector. It is shown that the alternating Hall
current generated by the alternating magnetic moment of the spin waves, reduces
the spin-wave damping. At strong enough unpolarized dc current the damping
changes sign, and the spin-wave amplitude starts to increase exponentially fast
with time. The critical current for the spin-wave instability is determined
mainly by the anomalous Hall effect, and can be much smaller than that for the
spin-torque mechanism of instability.",0802.4150v1
2019-06-05,Spin-Wave Optical Elements: Towards Spin-Wave Fourier Optics,"We perform micromagnetic simulations to investigate the propagation of
spin-wave beams through spin-wave optical elements. Despite spin-wave
propagation in magnetic media being strongly anisotropic, we use axicons to
excite spinwave Bessel-Gaussian beams and gradient-index lenses to focus spin
waves in analogy to conventional optics with light in isotropic media.
Moreover, we demonstrate spin-wave Fourier optics using gradient-index lenses.
These results contribute to the growing field of spin-wave optics.",1906.02301v1
2006-11-28,Strain amplification of the 4k$_F$ chain charge instability in Sr$_{14}$Cu$_{24}$O$_{41}$,"We have used resonant soft x-ray scattering (RSXS) to study the misfit strain
in Sr$_{14}$Cu$_{24}$O$_{41}$ (SCO), a cuprate that contains both doped spin
ladders and spin chains, as well as a ""control"" sample without holes,
La$_{6}$Ca$_{8}$Cu$_{24}$O$_{41}$ (LCCO). The misfit strain wave in SCO is
strongly temperature (T)-dependent and is accompanied by a substantial hole
modulation. In LCCO the strain wave is weaker, shows no hole modulation, and is
T-independent. The observed strain wave vector, $L_c=0.318$, is close to the
4k$_F$ instability of the chain. Our results indicate that the chain charge
order observed in SCO by several groups is a 4k$_F$ charge density wave (CDW)
amplified by the misfit strain in this material. This demonstrates a new
mechanism for CDW formation in condensed matter and resolves several
contraversies over the transport properties of SCO.",0611730v1
2019-01-17,Transition radiation in photonic topological crystals: quasi-resonant excitation of robust edge states by a moving charge,"We demonstrate, theoretically and experimentally, that a traveling electric
charge passing from one photonic crystal into another generates edge waves --
electromagnetic modes with frequencies inside the common photonic bandgap
localized at the interface -- via a process of transition edge-wave radiation
(TER). A simple and intuitive expression for the TER spectral density is
derived and then applied to a specific structure: two interfacing photonic
topological insulators with opposite spin-Chern indices. We show that TER
breaks the time-reversal symmetry and enables valley- and spin-polarized
generation of topologically protected edge waves propagating in one or both
directions along the interface. Experimental measurements at the Argonne
Wakefield Accelerator Facility are consistent with the excitation and
localization of the edge waves. The concept of TER paves the way for novel
particle accelerators and detectors.",1901.05640v3
2006-08-02,Spin Exchange Rates in Electron-Hydrogen Collisions,"The spin temperature of neutral hydrogen, which determines the 21 cm optical
depth and brightness temperature, is set by the competition between radiative
and collisional processes. In the high-redshift intergalactic medium, the
dominant collisions are typically those between hydrogen atoms. However,
collisions with electrons couple much more efficiently to the spin state of
hydrogen than do collisions with other hydrogen atoms and thus become important
once the ionized fraction exceeds ~1%. Here we compute the rate at which
electron-hydrogen collisions change the hydrogen spin. Previous calculations
included only S-wave scattering and ignored resonances near the n=2 threshold.
We provide accurate results, including all partial wave terms through the
F-wave, for the de-excitation rate at temperatures T_K < 15,000 K; beyond that
point, excitation to n>=2 hydrogen levels becomes significant. Accurate
electron-hydrogen collision rates at higher temperatures are not necessary,
because collisional excitation in this regime inevitably produces Lyman-alpha
photons, which in turn dominate spin exchange when T_K > 6200 K even in the
absence of radiative sources. Our rates differ from previous calculations by
several percent over the temperature range of interest. We also consider some
simple astrophysical examples where our spin de-excitation rates are useful.",0608067v1
1998-06-30,Effects of doping on spin correlations in the periodic Anderson model,"We studied the effects of hole doping on spin correlations in the periodic
Anderson model, mainly at the full and three-quarters-full lower bands cases.
In the full lower band case, strong anti-ferromagnetic correlations develop
when the on-site repulsive interaction strength $U$ becomes comparable to the
quasi-particle band width. In the three-quarters full case, a novel kind of
spin correlation develops that is consistent with the resonance between a
$(\pi,0)$ and a $(0,\pi)$ spin-density wave. In this state the spins on
different sublattices appear uncorrelated. Hole doping away from the completely
full case rapidly destroys the long-range anti-ferromagnetic correlations, in a
manner reminiscent of the destruction of anti-ferromagnetism in the Hubbard
model. In contrast to the Hubbard model, the doping does not shift the peak in
the magnetic structure factor from the $(\pi,\pi)$ position. At dopings
intermediate to the full and three-quarters full cases, only weak spin
correlations exist.",9806374v1
2005-10-07,Theory of orbital state and spin interactions in ferromagnetic titanates,"A spin-orbital superexchange Hamiltonian in a Mott insulator with $t_{2g}$
orbital degeneracy is investigated. More specifically, we focus on a spin
ferromagnetic state of the model and study a collective behavior of orbital
angular momentum. Orbital order in the model occurs in a nontrivial way -- it
is stabilized exclusively by quantum effects through the order-from-disorder
mechanism. Several energetically equivalent orbital orderings are identified.
Some of them are specified by a quadrupole ordering and have no unquenched
angular momentum at low energy. Other states correspond to a noncollinear
ordering of the orbital angular momentum and show the magnetic Bragg peaks at
specific positions. Order parameters are unusually small because of strong
quantum fluctuations. Orbital contribution to the resonant x-ray scattering is
discussed. The dynamical magnetic structure factor in different ordered states
is calculated. Predictions made should help to observe elementary excitations
of orbitals and also to identify the type of the orbital order in ferromagnetic
titanates. Including further a relativistic spin-orbital coupling, we derive an
effective low-energy spin Hamiltonian and calculate a spin-wave spectrum, which
is in good agreement with recent experimental observations in YTiO$_3$.",0510175v1
2005-09-28,Effective Spin Quantum Phases in Systems of Trapped Ions,"A system of trapped ions under the action of off--resonant standing--waves
can be used to simulate a variety of quantum spin models. In this work, we
describe theoretically quantum phases that can be observed in the simplest
realization of this idea: quantum Ising and XY models. Our numerical
calculations with the Density Matrix Renormalization Group method show that
experiments with ion traps should allow one to access general properties of
quantum critical systems. On the other hand, ion trap quantum spin models show
a few novel features due to the peculiarities of induced effective spin--spin
interactions which lead to interesting effects like long--range quantum
correlations and the coexistence of different spin phases.",0509197v1
2009-11-20,Spin Transfer Dynamics in Spin Valves with Out-of-plane Magnetized CoNi Free Layers,"We have measured spin transfer-induced dynamics in magnetic nanocontact
devices having a perpendicularly magnetized Co/Ni free layer and an in-plane
magnetized CoFe fixed layer. The frequencies and powers of the excitations
agree well with the predictions of the single-domain model and indicate that
the excited dynamics correspond to precessional orbits with angles ranging from
zero to 90 degrees as the applied current is increased at a fixed field. From
measurements of the onset current as a function of applied field strength we
estimate the magnitude of the spin torque asymmetry parameter lambda ~ 1.5. By
combining these with spin torque ferromagnetic resonance measurements, we also
estimate the spin wave radiation loss in these devices.",0911.4077v1
2010-06-01,High cooperativity coupling of electron-spin ensembles to superconducting cavities,"Electron spins in solids are promising candidates for quantum memories for
superconducting qubits because they can have long coherence times, large
collective couplings, and many quantum bits can be encoded into the spin-waves
of a single ensemble. We demonstrate the coupling of electron spin ensembles to
a superconducting transmission-line resonator at coupling strengths greatly
exceeding the cavity decay rate and comparable to spin linewidth. We also use
the enhanced coupling afforded by the small cross-section of the transmission
line to perform broadband spectroscopy of ruby at millikelvin temperatures at
low powers. In addition, we observe hyperfine structure in diamond P1 centers
and time domain saturation-relaxation of the spins.",1006.0242v1
2013-08-26,Spin lock composite and shaped pulses for efficient and robust pumping of dark states in magnetic resonance,"Long-lived (symmetry protected) hyperpolarized spin states offer important
new opportunities (for example, in clinical MR imaging), but existing methods
for producing these states are limited by either excess energy dissipation or
high sensitivity to inhomogeneities. We extend recent work on continuous-wave
irradiation of nearly-equivalent spins (spin-lock induced crossing) by
designing composite pulse and adiabatic shaped-pulse excitations which overcome
the limitations. These composite and adiabatic pulses differ drastically from
the traditional solutions in two-level systems. We also show this works in
chemically equivalent spin pairs, which has the advantage of allowing for
polarization transfer from and to remote spins. The approach is broadly
applicable to systems where varying excitation strength induces an avoided
crossing to a dark state, and thus to many other spectroscopic regimes.",1308.5666v1
2013-11-11,Spin relaxation in inhomogeneous quantum dot arrays studied by electron spin resonance,"Electron states in a inhomogeneous Ge/Si quantum dot array with groups of
closely spaced quantum dots were studied by conventional continuous wave ($cw$)
ESR and spin-echo methods. We find that the existence of quantum dot groups
allows to increase the spin relaxation time in the system. Created structures
allow us to change an effective localization radius of electrons by external
magnetic field. With the localization radius close to the size of a quantum dot
group, we obtain fourfold increasing spin relaxation time $T_1$, as compared to
conventional homogeneous quantum dot arrays. This effect is attributed to
averaging of local magnetic fields related to nuclear spins $^{29}$Si and
stabilization of $S_z$-polarization during electron back-and-forth motion
within a quantum dot group.",1311.2383v1
2014-12-05,Hidden-Beauty Charged Tetraquarks and Heavy Quark Spin Conservation,"Assuming the dominance of the spin-spin interaction in a diquark, we point
out that the mass difference in the beauty sector M(Z_b^prime) - M(Z_b) scales
with quark masses as expected in QCD, with respect to the corresponding mass
difference M(Z_c^prime) - M(Z_c). Notably, we show that the decays
Upsilon(10890) --> Upsilon(nS) pi pi and Upsilon(10890) --> (h_b(1P), h_b(2P))
pi pi are compatible with heavy-quark spin conservation if the contributions of
Z_b,Z_b^prime intermediate states are taken into account, Upsilon(10890) being
either a Upsilon(5S) or the beauty analog of Y_c(4260). Belle results on these
decays support the quark spin wave-function of the Z states as tetraquarks. We
also consider the role of light quark spin non-conservaton in Z_b,Z_b^prime
decays into B B^* and B^* B^*. Indications of possible signatures of the still
missing X_b resonance are proposed.",1412.2049v2
2015-02-13,Spin-current injection and detection in strongly correlated organic conductor,"Spin-current injection into an organic semiconductor
$\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}$ film induced by the spin
pumping from an yttrium iron garnet (YIG) film. When magnetization dynamics in
the YIG film is excited by ferromagnetic or spin-wave resonance, a voltage
signal was found to appear in the
$\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}$ film.
Magnetic-field-angle dependence measurements indicate that the voltage signal
is governed by the inverse spin Hall effect in
$\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}$. We found that the
voltage signal in the $\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}$/YIG
system is critically suppressed around 80 K, around which magnetic and/or glass
transitions occur, implying that the efficiency of the spin-current injection
is suppressed by fluctuations which critically enhanced near the transitions.",1502.05244v1
2018-06-06,Excitation of magnon spin photocurrents in antiferromagnetic insulators,"In the circular photogalvanic effect, circularly polarized light can produce
a direct electron photocurrent in metals and the direction of the current
depends on the polarization. We suggest that an analogous nonlinear effect
exists for antiferromagnetic insulators wherein the total spin of light and
spin waves is conserved. In consequence, a spin angular momentum is expected to
be transfered from photons to magnons so that a circularly polarized
electromagnetic field will generate a direct magnon spin current. The direction
of the current is determined by the helicity of the light. We show that this
resonant effect appears as a second order light-matter interaction. We find
also a geometric contribution to the spin photocurrent, which appears for
materials with complex lattice structures and Dzyaloshinskii-Moriya
interactions.",1806.02442v2
2018-07-13,Spinor self-ordering of a quantum gas in a cavity,"We observe the joint spin-spatial (spinor) self-organization of a
two-component BEC strongly coupled to an optical cavity. This unusual
nonequilibrium Hepp-Lieb-Dicke phase transition is driven by an off-resonant
two-photon Raman transition formed from a classical pump field and the emergent
quantum dynamical cavity field. This mediates a spinor-spinor interaction that,
above a critical strength, simultaneously organizes opposite spinor states of
the BEC on opposite checkerboard configurations of an emergent 2D lattice. The
resulting spinor density-wave polariton condensate is observed by directly
detecting the atomic spin and momentum state and by holographically
reconstructing the phase of the emitted cavity field. The latter provides a
direct measure of the spin state, and a spin-spatial domain wall is observed.
The photon-mediated spin interactions demonstrated here may be engineered to
create dynamical gauge fields and quantum spin glasses.",1807.04915v1
2019-02-28,Neutrino spin oscillations in external fields in curved spacetime,"We study spin oscillations of massive Dirac neutrinos in background matter,
electromagnetic and gravitational fields. First, using the Dirac equation for a
neutrino interacting with the external fields in curved spacetime, we rederive
the quasiclassical equation for the neutrino spin evolution, which was proposed
previously basing on principles of the general covariance. Then, we apply this
result for the description of neutrino spin oscillations in nonmoving and
unpolarized matter under the influence of a constant transverse magnetic field
and a gravitational wave. We derive the effective Schr\""odinger equation for
neutrino oscillations in these external fields and solve it numerically.
Choosing realistic parameters of external fields, we show that the parametric
resonance can take place in spin oscillations of low energy neutrinos. Some
astrophysical applications are briefly discussed.",1902.11285v2
2019-03-06,Honeycomb rare-earth magnets with anisotropic exchange interactions,"We study the rare-earth magnets on a honeycomb lattice, and are particularly
interested in the experimental consequences of the highly anisotropic spin
interaction due to the spin-orbit entanglement. We perform a high-temperature
series expansion using a generic nearest-neighbor Hamiltonian with anisotropic
interactions, and obtain the heat capacity, the parallel and perpendicular spin
susceptibilities, and the magnetic torque coefficients. We further examine the
electron spin resonance linewidth as an important signature of the anisotropic
spin interactions. Due to the small interaction energy scale of the rare-earth
moments, it is experimentally feasible to realize the strong-field regime.
Therefore, we perform the spin-wave analysis and study the possibility of
topological magnons when a strong field is applied to the system. The
application and relevance to the rare-earth Kitaev materials are discussed.",1903.02530v3
2020-09-30,Dynamical properties of a driven dissipative dimerized $S = 1/2$ chain,"We consider the dynamical properties of a gapped quantum spin system coupled
to the electric field of a laser, which drives the resonant excitation of
specific phonon modes that modulate the magnetic interactions. We deduce the
quantum master equations governing the time-evolution of both the lattice and
spin sectors, by developing a Lindblad formalism with bath operators providing
an explicit description of their respective phonon-mediated damping terms. We
investigate the nonequilibrium steady states (NESS) of the spin system
established by a continuous driving, delineating parameter regimes in driving
frequency, damping, and spin-phonon coupling for the establishment of
physically meaningful NESS and their related non-trivial properties. Focusing
on the regime of generic weak spin-phonon coupling, we characterize the NESS by
their frequency and wave-vector content, explore their transient and relaxation
behavior, and discuss the energy flow, the system temperature, and the critical
role of the type of bath adopted. Our study lays a foundation for the
quantitative modelling of experiments currently being designed to control
coherent many-body spin states in quantum magnetic materials.",2009.14805v2
2020-11-24,Optical isolation induced by subwavelength spinning particle via spin-orbit interaction,"Optical isolation enables nonreciprocal manipulations of light with broad
applications in optical communications. Optical isolation by rotating
structures has drawn considerable attention due to its magnetic-free nature and
unprecedented performance. Conventional rotation-based optical isolation relies
on the use of bulky cavities hindering applications in subwavelength photonics.
Here, we propose a novel mechanism of optical isolation by integrating the
unique dispersion of a hyperbolic metamaterial with the transverse spin-orbit
interaction of evanescent waves. We show that rotation of a subwavelength
hyperbolic nanoparticle breaks the time-reversal symmetry and yields two
resonant chiral modes that selectively couple to the transverse spin of
waveguide modes. Remarkably, the transverse spin-orbit interaction can give
rise to unidirectional coupling and $>95\%$ isolation of infrared light at an
experimentally feasible rotation speed. Our work fuses the two important fields
of optical isolation and photonic spin-orbit interactions, leading to
magnetic-free yet compact nonreciprocal devices for novel applications in
optical communications, chiral quantum optics, and topological photonics.",2011.11973v2
2019-12-20,Efficient Ab-initio Multiplet Calculations for Magnetic Adatoms on MgO,"Scanning probe microscopy and spectroscopy, and more recently in combination
with electron spin resonance, have allowed the direct observation of electron
dynamics on the single-atom limit. The interpretation of data is strongly
depending on model Hamiltonians. However, fitting effective spin Hamiltonians
to experimental data lacks the ability to explore a vast number of potential
systems of interest. By using plane-wave density functional theory (DFT) as
starting point, we build a multiplet Hamiltonian making use of
maximally-localized Wannier functions. The Hamiltonian contains spin-orbit and
electron-electron interactions needed to obtain the relevant spin dynamics. The
resulting reduced Hamiltonian is solved by exact diagonalization. We compare
three prototypical cases of 3d transition metals Mn (total spin $S=5/2$), Fe
($S=2$) and Co ($S=3/2$) on MgO with experimental data and find that our
calculations can accurately predict the spin orientation and anisotropy of the
magnetic adatom. Our method does not rely on experimental input and permits us
to explore and predict the fundamental magnetic properties of adatoms on
surfaces.",1912.09793v1
2023-02-24,A Fiber-coupled Scanning Magnetometer with Nitrogen-Vacancy Spins in a Diamond Nanobeam,"Magnetic imaging with nitrogen-vacancy (NV) spins in diamond is becoming an
established tool for studying nanoscale physics in condensed matter systems.
However, the optical access required for NV spin readout remains an important
hurdle for operation in challenging environments such as millikelvin cryostats
or biological systems. Here, we demonstrate a scanning-NV sensor consisting of
a diamond nanobeam that is optically coupled to a tapered optical fiber. This
nanobeam sensor combines a natural scanning-probe geometry with high-efficiency
through-fiber optical excitation and readout of the NV spins. We demonstrate
through-fiber optically interrogated electron spin resonance and
proof-of-principle magnetometry operation by imaging spin waves in an
yttrium-iron-garnet thin film. Our scanning-nanobeam sensor can be combined
with nanophotonic structuring to control the light-matter interaction strength,
and has potential for applications that benefit from all-fiber sensor access
such as millikelvin systems.",2302.12536v1
2017-07-04,Optimised frequency modulation for continuous-wave optical magnetic resonance sensing using nitrogen-vacancy ensembles,"Magnetometers based on ensembles of nitrogen-vacancy centres are a promising
platform for continuously sensing static and low-frequency magnetic fields.
Their combination with phase-sensitive (lock-in) detection creates a highly
versatile sensor with a sensitivity that is proportional to the derivative of
the optical magnetic resonance lock-in spectrum, which is in turn dependant on
the lock-in modulation parameters. Here we study the dependence of the lock-in
spectral slope on the modulation of the spin-driving microwave field. Given the
presence of the intrinsic nitrogen hyperfine spin transitions, we
experimentally show that when the ratio between the hyperfine linewidth and
their separation is $\gtrsim 1/4$, square-wave based frequency modulation
generates the steepest slope at modulation depths exceeding the separation of
the hyperfine lines, compared to sine-wave based modulation. We formulate a
model for calculating lock-in spectra which shows excellent agreement with our
experiments, and which shows that an optimum slope is achieved when the
linewidth/separation ratio is $\lesssim 1/4$ and the modulation depth is less
then the resonance linewidth, irrespective of the modulation function used.",1707.00916v1
2019-01-10,Spin-wave Confinement and Coupling in Organic-Based Magnetic Nanostructures,"Vanadium tetracyanoethylene (V[TCNE]$_\text{x}$) is an organic-based
ferrimagnet that exhibits robust magnetic ordering (T$_\text{C}$ of over 600
K), high quality-factor (high-Q) microwave resonance (Q up to 3,500), and
compatibility with a wide variety of substrates and encapsulation technologies.
Here, we substantially expand the potential scope and impact of this emerging
material by demonstrating the ability to produce engineered nanostructures with
tailored magnetic anisotropy that serve as a platform for the exploration of
cavity magnonics, revealing strongly coupled quantum confined standing wave
modes that can be tuned into and out of resonance with an applied magnetic
field. Specifically, time-domain micromagnetic simulations of these
nanostructures faithfully reproduce the experimentally measured spectra,
including the quasi-uniform mode and higher-order spin-wave (magnon) modes.
Finally, when the two dominant magnon modes present in the spectra are brought
into resonance by varying the orientation of the in-plane magnetic field, we
observe anti-crossing behavior indicating strong coherent coupling between
these two magnon modes at room temperature. These results position
V[TCNE]$_\text{x}$ as a leading candidate for the development of coherent
magnonics, with potential applications ranging from microwave electronics to
quantum information.",1901.03286v2
2018-04-17,Fate of the open-shell singlet ground state in the experimentally accessible acenes: a quantum Monte Carlo study,"By means of the Jastrow correlated antisymmetrized geminal power (JAGP) wave
function and quantum Monte Carlo (QMC) methods, we study the ground state
properties of the oligoacene series, up to the nonacene. The JAGP is the
accurate variational realization of the resonating-valence-bond (RVB) ansatz
proposed by Pauling and Wheland to describe aromatic compounds. We show that
the long-ranged RVB correlations built in the acenes' ground state are
detrimental for the occurrence of open-shell diradical or polyradical
instabilities, previously found by lower-level theories. We substantiate our
outcome by a direct comparison with another wave function, tailored to be an
open-shell singlet (OSS) for long-enough acenes. By comparing on the same
footing the RVB and OSS wave functions, both optimized at a variational QMC
level, and further projected by the lattice regularized diffusion Monte Carlo
(LRDMC) method, we prove that the RVB wave function has always a lower
variational energy and better nodes than the OSS, for all molecular species
considered in this work. The entangled multi-reference RVB state acts against
the electron edge localization implied by the OSS wave function, and weakens
the diradical tendency for higher oligoacenes. These properties are reflected
by several descriptors, including wave function parameters, bond length
alternation, aromatic indices, and spin-spin correlation functions. In this
context, we propose a new aromatic index estimator suitable for geminal wave
functions. For the largest acenes taken into account, the long-range decay of
the charge-charge correlation functions is compatible with a quasi-metallic
behavior.",1804.06276v1
2023-02-02,Ultrastrong Magnon-Photon Coupling Achieved by Magnetic Films in Contact with Superconducting Resonators,"Coherent coupling between spin wave excitations (magnons) and microwave
photons in a cavity may disclose new paths to unconventional phenomena as well
as for novel applications. Here, we present a systematic investigation on YIG
(Yttrium Iron Garnet) films on top of coplanar waveguide resonators made of
superconducting YBCO. We first show that spin wave excitations with frequency
higher than the Kittel mode can be excited by putting in direct contact a
5~$\mu$m thick YIG film with the YBCO coplanar resonator (cavity frequency
$\omega_c/2 \pi = 8.65$~GHz). With this configuration, we obtain very large
values of the collective coupling strength $\lambda/2 \pi \approx 2$~GHz and
cooperativity $C=5 \times 10^4$. Transmission spectra are analyzed by a
modified Hopfield model for which we provide an exact solution that allows us
to well reproduce spectra by introducing a limited number of free parameters.
It turns out that the coupling of the dominant magnon mode with photons exceeds
0.2 times the cavity frequency, thus demonstrating the achievement of the
ultrastrong coupling regime with this architecture. Our analysis also shows a
vanishing contribution of the diamagnetic term which is a peculiarity of pure
spin systems.",2302.00804v2
2011-08-30,Spin-exotic search in the $ρπ$ decay channel: New results on $π^{-}π^{0}π^{0}$ in comparison to $π^{-}π^{+}π^{-}$ final states (diffractively produced on proton),"The COMPASS experiment at CERN SPS features charged particle tracking as well
as good coverage by electromagnetic calorimetry, and our data provide an
excellent opportunity for simultaneous observation of new states in different
decay modes by the same experiment. The existence of the spin-exotic
$\pi_1(1600)$ resonance in the $\rho\pi$ decay channel is studied for the first
time at COMPASS in both decay modes of the diffractively produced $(3\pi)^{-}$
system: $\pi^{-}p \rightarrow \pi^{-}\pi^{+}\pi^{-}p$ and $\pi^{-} p
\rightarrow \pi^{-}\pi^{0}\pi^{0} p$. A preliminary partial-wave analysis
performed on the 2008 proton target data allows for a first conclusive
comparison of both $(3\pi)^{-}$ decay modes not only for main waves but also
for small ones. We find the neutral versus charged mode results in excellent
agreement with expectations from isospin symmetry. Both, the intensities and
the relative phases to well-known resonances, are consistent for the neutral
and the charged decay modes of the $(3\pi)^{-}$ system. The status on the
search for the spin-exotic $\pi_1(1600)$ resonance produced on a proton target
is discussed.",1108.5969v1
2009-03-20,Quantum computing with an electron spin ensemble,"We propose to encode a register of quantum bits in different collective
electron spin wave excitations in a solid medium. Coupling to spins is enabled
by locating them in the vicinity of a superconducting transmission line cavity,
and making use of their strong collective coupling to the quantized radiation
field. The transformation between different spin waves is achieved by applying
gradient magnetic fields across the sample, while a Cooper Pair Box, resonant
with the cavity field, may be used to carry out one- and two-qubit gate
operations.",0903.3506v2
2010-11-05,Spin-Density Wave near the Vortex Cores of Bi$_2$Sr$_2$CaCu$_2$O$_{8+δ}$,"Competition with magnetism is at the heart of high temperature
superconductivity, most intensely felt near a vortex core. To investigate
vortex magnetism we have developed a spatially resolved probe using nuclear
magnetic resonance. Our spin-lattice-relaxation spectroscopy is spatially
resolved both within a conduction plane as well as from one plane to another.
With this approach we have found a spin-density wave associated with the vortex
core in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$, which is expected from scanning
tunneling microscope observations of ""checkerboard"" patterns in the local
density of electronic states.[1] We determine both the spin-modulation
amplitude and decay length from the vortex core in fields up to H=30 T.",1011.1520v1
2011-10-03,Field-induced collective spin-exciton condensation in a quasi-2D dx2-y2-wave heavy electron superconductor,"The origin of the spin resonance observed in CeCoIn5 with Inelastic Neutron
Scattering is subject to debate. It has been shown recently that in this heavy
electron compound at low temperature an instability to a ground state with
coexisting dx2 -y2 -wave superconductivity and Spin Density Wave (SDW) order in
a magnetic field is a corollary of the consideration of a collective spin
excitation mode in a quasi-2D dx2 -y2 -wave Pauli-limited superconductor. This
provides a natural scenario for the occurence of the puzzling
high-field-low-temperature phase highlighted in CeCoIn5 . We present
perspectives on this ground state transition and propose directions for future
experiment.",1110.0387v3
2017-05-09,Low spin wave damping in the insulating chiral magnet Cu$_{2}$OSeO$_{3}$,"Chiral magnets with topologically nontrivial spin order such as Skyrmions
have generated enormous interest in both fundamental and applied sciences. We
report broadband microwave spectroscopy performed on the insulating chiral
ferrimagnet Cu$_{2}$OSeO$_{3}$. For the damping of magnetization dynamics we
find a remarkably small Gilbert damping parameter of about $1\times10^{-4}$ at
5 K. This value is only a factor of 4 larger than the one reported for the best
insulating ferrimagnet yttrium iron garnet. We detect a series of sharp
resonances and attribute them to confined spin waves in the mm-sized samples.
Considering the small damping, insulating chiral magnets turn out to be
promising candidates when exploring non-collinear spin structures for high
frequency applications.",1705.03416v1
2019-09-01,Magnetic field-dependent low-energy magnon dynamics in $α$-RuCl3,"Revealing the spin excitations of complex quantum magnets is key to
developing a minimal model that explains the underlying magnetic correlations
in the ground state. We investigate the low-energy magnons in $\alpha$-RuCl$_3$
by combining time-domain terahertz spectroscopy under an external magnetic
field and model Hamiltonian calculations. We observe two absorption peaks
around 2.0 and 2.4 meV, which we attribute to zone-center spin waves. Using
linear spin-wave theory with only nearest-neighbor terms of the exchange
couplings, we calculate the antiferromagnetic resonance frequencies and reveal
their dependence on an external field applied parallel to the nearest-neighbor
Ru-Ru bonds. We find that the magnon behavior in an applied magnetic field can
be understood only by including an off-diagonal $\Gamma$ exchange term to the
minimal Heisenberg-Kitaev model. Such an anisotropic exchange interaction that
manifests itself as a result of strong spin-orbit coupling can naturally
account for the observed mixing of the modes at higher fields strengths.",1909.00462v1
2021-05-05,Probing the Spins of Supermassive Black Holes with Gravitational Waves from Surrounding Compact Binaries,"Merging compact black-hole (BH) binaries are likely to exist in the nuclear
star clusters around supermassive BHs (SMBHs), such as Sgr A$^\ast$. They may
also form in the accretion disks of active galactic nuclei. Such compact
binaries can emit gravitational waves (GWs) in the low-frequency band (0.001-1
Hz) that are detectable by several planned space-borne GW observatories. We
show that the orbital axis of the compact binary may experience significant
variation due to the frame-dragging effect associated with the spin of the
SMBH. The dynamical behavior of the orbital axis can be understood analytically
as a resonance phenomenon. We show that rate of change of the binary orbital
axis encodes the information on the spin of the SMBH. Therefore detecting GWs
from compact binaries around SMBHs, particularly the modulation of the waveform
associated with the variation of the binary orbital axis, can provide a new
probe on the spins of SMBHs.",2105.02230v2
2015-12-02,Optically tunable spin transport on the surface of a topological insulator,"The emerging field of spinoptronics has a potential to supersede the
functionality of modern electronics, while a proper description of strong
light-matter coupling pose the most intriguing questions from both fundamental
scientific and technological perspectives. In this paper we address a highly
relevant issue for such a development. We theoretically explore spin dynamics
on the surface of a 3D topological insulator (TI) irradiated with an
off-resonant high-frequency electromagnetic wave. The strong coupling between
electrons and the electromagnetic wave drastically modifies the spin properties
of TI. The effects of irradiation are shown to result in anisotropy of electron
energy spectrum near the Dirac point and suppression of spin current and are
investigated in detail in this work.",1512.00798v2
2018-07-06,Counterroating incommensurate magnetic order and strong quantum fluctuations in the honeycomb layers of $\rm NaNi_2BiO_6$,"We report the magnetic structure and electronic properties of the honeycomb
antiferromagnet $\rm NaNi_2BiO_{5.66}$. We find magnetic order with moments
along the $c$ axis for temperatures below $T_{c1}=6.3(1)\>{\rm K}$ and then in
the honeycomb plane for $T < T_{c2}=4.8(1)\>{\rm K}$ with a counterrotating
pattern and an ordering wave vector ${\bf q}=(\frac{1}{3},\> \frac{1}{3},\>
0.15(1))$. Density functional theory and electron spin resonance indicate this
is high-spin Ni$^{3+}$ magnetism near a high to low spin transition. The
ordering wave vector, in-plane magnetic correlations, missing entropy, spin
state, and superexchange pathways are all consistent with bond-dependent
Kitaev-$\Gamma$-Heisenberg exchange interactions in $\rm NaNi_2BiO_{6-\delta}$.",1807.02528v2
2020-04-02,Spin-Dependent Charge-Carrier Recombination Processes in Tris(8-Hydroxyquinolinato) Aluminum,"We have studied the nature and dynamics of spin-dependent charge carrier
recombination in Tris(8-hydroxyquinolinato) aluminum (Alq$_3$) films in light
emitting diodes at room temperature using continuous wave and pulsed
electrically detected magnetic resonance (EDMR) spectroscopy. We found that the
EDMR signal is dominated by an electron-hole recombination process, and
another, weaker EDMR signal whose fundamental nature was investigated. From the
pulsed EDMR measurements we obtained a carrier spin relaxation time, $T_2 =
45\pm 25$ ns which is much shorter than $T_2$ in conjugated polymers, but
relatively long for a molecule containing elements with high atomic number.
Using multi-frequency continuous wave EDMR spectroscopy, we obtained the local
hyperfine field distributions for electrons and holes, as well as their
respective spin-orbit coupling induced g-factor and g-strain values.",2004.00765v1
2021-05-03,First ESR Detection of Higgs Amplitude Mode and Analysis with Extended Spin-Wave Theory in Dimer System KCuCl$_3$,"KCuCl$_3$ is known to show a quantum phase transition from the disordered to
antiferromagnetically ordered phases by applying pressure. There is a
longitudinal excitation mode (Higgs amplitude mode) in the vicinity of the
quantum critical point in the ordered phase. To detect the Higgs amplitude
mode, high-pressure ESR measurements are performed in KCuCl$_3$. The
experimental data are analyzed by the extended spin-wave theory on the basis of
the vector spin chirality. We report the first ESR detection of the Higgs
amplitude mode and the important role of the electric dipole described by the
vector spin chirality.",2105.00750v1
2022-09-06,Current-driven magnetization dynamics and their correlation with magnetization configurations in perpendicularly magnetized tunnel junctions,"We study spin-transfer-torque driven magnetization dynamics of a
perpendicular magnetic tunnel junction (MTJ) nanopillar. Based on the
combination of spin-torque ferromagnetic resonance and microwave spectroscopy
techniques, we demonstrate that the free layer (FL) and the weak pinned
reference layer (RL) exhibit distinct dynamic behaviors with opposite frequency
vs. field dispersion relations. The FL can support a single coherent spin-wave
(SW) mode for both parallel and antiparallel configurations, while the RL
exhibits spin-wave excitation only for the antiparallel state. These two SW
modes corresponding to the FL and RL coexist at an antiparallel state and
exhibit a crossover phenomenon of oscillation frequency with increasing the
external magnetic field, which could be helpful in the mutual synchronization
of auto-oscillations for SW-based neuromorphic computing.",2209.02271v1
2021-01-06,Role of wave-particle resonance in turbulent transport in toroidal plasmas,"Wave-particle interaction in toroidal plasmas is an essential transport
mechanism in drift wave instability-driven microturbulence. In tokamkas,
different wave-particle resonance conditions have been found important for the
energy and particle transport of multiple species in various drift wave
turbulences. To confirm the transport mechanism for electrons and ions in
tokamak drift-wave instabilities, the effect of wave-particle resonance on
turbulent transport is studied using global gyrokinetic particle simulations of
the plasma core ion temperature gradient (ITG) and collisionless trapped
electron mode (CTEM) turbulence. Simulation results show that in CTEM and ITG
turbulence, electron transport is primarily regulated by wave-particle linear
resonance, and the ion transport is regulated by nonlinear wave-particle
decorrelation.",2101.01924v1
2017-12-13,Persistence of the gapless spin liquid in the breathing kagome Heisenberg antiferromagnet,"The nature of the ground state of the spin $S=1/2$ Heisenberg antiferromagnet
on the kagome lattice with breathing anisotropy (i.e., with different
superexchange couplings $J_{\vartriangle}$ and $J_{\triangledown}$ within
elementary up- and down-pointing triangles) is investigated within the
framework of Gutzwiller projected fermionic wave functions and Monte Carlo
methods. We analyze the stability of the U(1) Dirac spin liquid with respect to
the presence of fermionic pairing that leads to a gapped $\mathbb{Z}_{2}$ spin
liquid. For several values of the ratio $J_{\triangledown}/J_{\vartriangle}$,
the size scaling of the energy gain due to the pairing fields and the
variational parameters are reported. Our results show that the energy gain of
the gapped spin liquid with respect to the gapless state either vanishes for
large enough system size or scales to zero in the thermodynamic limit.
Similarly, the optimized pairing amplitudes (responsible for opening the spin
gap) are shown to vanish in the thermodynamic limit. Our outcome is
corroborated by the application of one and two Lanczos steps to the gapless and
gapped wave functions, for which no energy gain of the gapped state is detected
when improving the quality of the variational states. Finally, we discuss the
competition with the ""simplex"" $\mathbb{Z}_{2}$ resonating-valence-bond spin
liquid, valence-bond crystal, and nematic states in the strongly anisotropic
regime, i.e., $J_{\triangledown} \ll J_{\vartriangle}$.",1712.04579v2
2019-04-03,Spin waves and spin-state transitions in a ruthenate high-temperature antiferromagnet,"Ruthenium compounds play prominent roles in materials research ranging from
oxide electronics to catalysis, and serve as a platform for fundamental
concepts such as spin-triplet superconductivity, Kitaev spin-liquids, and
solid-state analogues of the Higgs mode in particle physics. However, basic
questions about the electronic structure of ruthenates remain unanswered,
because several key parameters (including the Hund's-rule, spin-orbit, and
exchange interactions) are comparable in magnitude, and their interplay is
poorly understood - partly due to difficulties in synthesizing sizable single
crystals for spectroscopic experiments. Here we introduce a resonant inelastic
x-ray scattering (RIXS) technique capable of probing collective modes in
microcrystals of $4d$-electron materials. We present a comprehensive set of
data on spin waves and spin-state transitions in the honeycomb antiferromagnet
SrRu$_{2}$O$_{6}$, which possesses an unusually high N\'eel temperature. The
new RIXS method provides fresh insight into the unconventional magnetism of
SrRu$_{2}$O$_{6}$, and enables momentum-resolved spectroscopy of a large class
of $4d$ transition-metal compounds.",1904.01930v2
2024-03-13,Synergy between Spin and Orbital Angular Momenta on a Möbius Strip,"Spin and orbital angular momenta are fundamental physical characteristics
described by polarization and spatial degrees of freedom, respectively.
Polarization is a feature of vector fields while spatial phase gradient
determines the orbital angular momentum ubiquitous to any scalar field. Common
wisdom treats these two degrees of freedom as distinct and independent
principles to manipulate wave propagations. Here, we demonstrate their synergy.
This is achieved by introducing two orthogonal $p$-orbitals as eigenbases,
whose spatial modal features are exploited to generate orbital angular momenta
and the associated orbital orientations provide means to simultaneously
manipulate polarizations. Through periodic modulation and directional coupling,
we realize a full cyclic evolution of the synchronized and synergized
spin-orbital angular momenta. Remarkably, this evolution acquires a nontrivial
geometric phase, leading to its representation on a M\""obius strip.
Experimentally, an acoustic cavity array is designed, whose dipole resonances
precisely mimic the $p$-orbitals. The acoustic waves, uniquely, see the
pressure (scalar) field as a spatial feature and carry an intrinsic
polarization defined by the velocity (vector) field, serving as an ideal
platform to observe the synergy of spin and orbital angular momenta. Based on
such a property, we further showcase a spin-orbital-Hall effect, highlighting
the intricate locking of handedness, directionality, spin density and spatial
mode profile. Our study unveils a fundamental connection between spin and
orbital angular momenta, promising avenues for novel applications in
information coding and high-capacity communications.",2403.08276v1
2010-02-05,Precision Meson Spectroscopy at COMPASS,"We present first results of a partial wave analysis of the diffractive
reaction $\pi- Pb \to \pi- \pi+ \pi- Pb$ based on data from the COMPASS
experiment taken during a pilot run in 2004 using a 190 GeV/c $\pi-$ beam on a
lead target. The analysis was performed in the region of squared four-momentum
transfer $t'$ between 0.1 and 1.0 (GeV/c)^2. The $\pi- \pi+ \pi-$ final state
shows a rich spectrum of well-known resonances. In addition a spin-exotic
$J^{PC} = 1^{-+}$ state with significant intensity was observed at 1.66 GeV/c^2
in the $\rho(770) \pi$ decay channel in natural parity exchange. The resonant
nature of this state is manifest in the mass dependence of its phase difference
to $J^{PC} = 1^{++}$ and $2^{-+}$ waves. The measured resonance parameters are
consistent with the disputed $\pi_1(1600)$. An outlook on the analyses of the
much larger data set taken during 2008 and 2009 is given.",1002.1272v1
2018-04-20,Partial-Wave Analysis of $γp \rightarrow K^+ Λ$ using a multichannel framework,"Results from a partial-wave analysis of the reaction $\gamma p \rightarrow
K^+ \Lambda$ are presented. The reaction is dominated by the $S_{11}(1650)$ and
$P_{13}(1720)$ resonances at low energies and by $P_{13}(1900)$ at higher
energies. There are small contributions from all amplitudes up to and including
$G_{17}$, with $F_{17}$ necessary for obtaining a good fit of several of the
spin observables. We find evidence for $P_{11}$(1880), $D_{13}$(2120), and
$D_{15}$(2080) resonances, as well as a possible $F_{17}$ resonance near 2300
MeV, which is expected from quark-model predictions. Some predictions for
$\gamma n \to K^0 \Lambda$ are also included.",1804.07422v3
2022-02-07,Magnetization dynamics affected by phonon pumping,"""Pumping"" of phonons by a dynamic magnetization promises to extend the range
and functionality of magnonic devices. We explore the impact of phonon pumping
on room-temperature ferromagnetic resonance (FMR) spectra of bilayers of thin
yttrium iron garnet (YIG) films on thick gadolinium gallium garnet substrates
over a wide frequency range. At low frequencies the Kittel mode hybridizes
coherently with standing ultrasound waves of a bulk acoustic resonator to form
magnon polarons that induce rapid oscillations of the magnetic susceptibility,
as reported before. At higher frequencies, the phonon resonances overlap,
merging into a conventional FMR line, but with an increased line width. The
frequency dependence of the increased line broadening follows the predictions
from phonon pumping theory in the thick substrate limit. In addition, we find
substantial magnon-phonon coupling of a perpendicular standing spin wave (PSSW)
mode. This evidences the importance of the mode overlap between the acoustic
and magnetic modes, and provides a route towards engineering the magnetoelastic
mode coupling.",2202.03331v1
2018-04-24,$\text{Co}_{25}\text{Fe}_{75}$ Thin Films with Ultralow Total Damping,"We measure the dynamic properties of $\text{Co}_{25}\text{Fe}_{75}$ thin
films grown by dc magnetron sputtering. Using ferromagnetic resonance
spectroscopy, we demonstrate an ultralow total damping parameter in the
out-of-plane configuration of < 0.0013, whereas for the in-plane configuration
we find a minimum total damping of < 0.0020. In both cases, we observe low
inhomogeneous linewidth broadening in macroscopic films. We observe a minimum
full-width half-maximum linewidth of 1 mT at 10 GHz resonance frequency for a
12 nm thick film. We characterize the morphology and structure of these films
as a function of seed layer combinations and find large variation of the
qualitative behavior of the in-plane linewidth vs. resonance frequency.
Finally, we use wavevector-dependent Brillouin light scattering spectroscopy to
characterize the spin-wave dispersion at wave vectors up to 23 $\mu
\text{m}^{-1}$.",1804.08786v1
2003-07-23,Dispersion of Magnetic Excitations in Superconducting Optimally Doped YBa_2Cu_3O_6.95,"Detailed neutron scattering measurements of YBa_2Cu_3O_6.95 found that the
resonance peak and incommensurate magnetic scattering induced by
superconductivity represent the same physical phenomenon: two dispersive
branches that converge near 41 meV and the in-plane wave-vector q_af=(pi/a,
pi/a) to form the resonance peak. One branch has a circular symmetry around
q_af and quadratic downward dispersion from ~41 meV to the spin gap of
33+-1meV. The other, of lower intensity, disperses from ~41 meV to at least 55
meV. Our results exclude a quartet of vertical incommensurate rods in q-w space
expected from spin waves produced by dynamical charge stripes as an origin of
the observed incommensurate scattering in optimally-doped YBCO.",0307591v3
2000-11-22,Experimental Test of Complementarity by Nuclear Magnetic Resonance Techniques,"We have tested complementarity for the ensemble-averaged spin states of
nuclei $^{13}$C in the molecule of $^{13}$CHCl$_{3}$ by the use of the spin
states of another nuclei $^{1}$H as the path marker. It turns out that the
wave-particle duality holds when one merely measures the probability density of
quantum states, and that the wave- and particle-like behavior is simultaneously
observed with the help of measuring populations and coherence in a single
nuclear magnetic resonance(NMR) experiment. Effects of path-marking schemes and
causes of the appearance and disappearance of the wave behavior are analysed.",0011094v2
2011-08-10,Distribution of Localized States from Fine Analysis of Electron Spin Resonance Spectra in Organic Transistors,"We developed a novel method for obtaining the distribution of trapped
carriers over their degree of localization in organic transistors, based on the
fine analysis of electron spin resonance spectra at low enough temperatures
where all carriers are localized. To apply the method to pentacene thin-film
transistors, we proved through continuous wave saturation experiments that all
carriers are localized at below 50 K. We analyzed the spectra at 20 K and found
that the major groups of traps comprise localized states having wave functions
spanning around 1.5 and 5 molecules and a continuous distribution of states
with spatial extent in the range between 6 and 20 molecules.",1108.2090v1
2012-07-23,Frequency Conversion in a High Q-factor Sapphire Whispering Gallery Mode Resonator due to Paramagnetic Nonlinearity,"Nonlinear frequency conversion is a well known and widely exploited family of
effects in optics, often arising from a Kerr nonlinearity in a crystal medium.
Here, we report high stability frequency conversion in the microwave regime due
to a $\chi^{(3)}$ nonlinearity in sapphire introduced by a dilute concentration
of paramagnetic spins. First, we produce a high stability comb from two
microwave fields at 12.029 and 12.037 GHz corresponding to two high $Q$-factor
Whispering Gallery (WG) modes within the Electron Spin Resonance (ESR)
bandwidth of the Fe$^{3+}$ ion. The resulting comb is generated by a cascaded
four-wave mixing effect with a 7.7 MHz repetition rate. Then, by suppressing
four-wave mixing by increasing the threshold power, third harmonic generation
is achieved in a variety of WG modes coupled to various species of paramagnetic
ion within the sapphire.",1207.5341v1
2013-05-30,Evolution of ferromagnetic and spin-wave resonances with crystalline order in thin films of full-Heusler alloy Co2MnSi,"We report the evolution of magnetic moment as well as magnetic anisotropy
with crystalline order in Co$_2$MnSi thin films grown on $(100)$ MgO by pulsed
laser deposition. The films become more ordered as the annealing temperature
($T_A$) increases from 400 to 600 $^0$C. The extent of \emph{L}$2_1$ ordering
in the films annealed at 600 $^0$C is $\approx 96%$. The static magnetization
measurements by vibrating sample magnetometry shows a maximum moment of 4.95
$\mu_B$ per formula unit with low coercivity ($H_C$ $\approx$ 65 Oe) in the
films annealed at 600 $^0$C. A rigorous analysis of the azimuthal and polar
angle dependent ferromagnetic resonance (FMR) measured at several temperatures
allows determination of various anisotropy fields relevant to our system as a
function of $T_A$. Finally, we have evaluated the exchange stiffness constant
down to 100 K using spin wave modes in FMR spectra. We have also estimated the
exchange energies as well as stiffness constant by varying the lattice
parameter \emph{ab-initio} using the Korringa-Kohn-Rostoker method.",1305.7048v1
2014-11-13,Non-linear radial spinwave modes in thin magnetic disks,"We present an experimental investigation of radial spin-wave modes in
magnetic nano-disks with a vortex ground state. The spin-wave amplitude was
measured using a frequency-resolved magneto optical network analyzer, allowing
for high-resolution resonance curves to be recorded. It was found that with
increasing excitation amplitude up to about 10 mT, the lowest-order mode
behaves strongly non-linearly as the mode frequency redshifts and the resonance
peak strongly deforms. This behavior was quantitatively reproduced by
micromagnetic simulations. At higher excitation the spinwaves are transformed
into a soliton by self-focusing, and collapse onto the vortex core, dispersing
the energy in short-wavelength spinwaves. Additionally, this process can lead
to switching of the vortex polarization through the injection of a Bloch point.",1411.3470v1
2015-10-26,Entanglement Entropy and Topological Order in Resonating Valence-Bond Quantum Spin Liquids,"On the triangular and kagome lattices, short-ranged resonating valence bond
(RVB) wave functions can be sampled without the sign problem using a
recently-developed Pfaffian Monte Carlo scheme. In this paper, we study the
Renyi entanglement entropy in these wave functions using a replica-trick
method. Using various spatial bipartitions, including the Levin-Wen
construction, our finite-size scaled Renyi entropy gives a topological
contribution consistent with $\gamma = \text{ln}(2)$, as expected for a gapped
$\mathbb{Z}_{2}$ quantum spin liquid. We prove that the mutual statistics are
consistent with the toric code anyon model and rule out any other quasiparticle
statistics such as the double semion model.",1510.07682v3
2020-09-10,Resonating valence bond realization of spin-1 non-Abelian chiral spin liquid on the torus,"We propose resonating valence bond wave functions for a spin-1 system on the
torus that realize a non-Abelian chiral spin liquid. The wave functions take
the form of infinite dimensional matrix product states constructed from
conformal blocks of the $\mathrm{SO}(3)_{1}$ Wess-Zumino-Witten model. This
means that they are lattice analogues of the bosonic Moore-Read state
introduced in fractional quantum Hall systems. The topological order of this
system is revealed by explicit construction of three-fold degenerate ground
states and analytical computation of the modular S and T matrices.",2009.04911v2
2021-02-06,Spin-wave eigenmodes in direct-write 3D nanovolcanoes,"Extending nanostructures into the third dimension has become a major research
avenue in modern magnetism, superconductivity and spintronics, because of
geometry-, curvature- and topology-induced phenomena. Here, we introduce Co-Fe
nanovolcanoes-nanodisks overlaid by nanorings-as purpose-engineered 3D
architectures for nanomagnonics, fabricated by focused electron beam induced
deposition. We use both perpendicular spin-wave resonance measurements and
micromagnetic simulations to demonstrate that the rings encircling the volcano
craters harbor the highest-frequency eigenmodes, while the lower-frequency
eigenmodes are concentrated within the volcano crater, due to the
non-uniformity of the internal magnetic field. By varying the crater diameter,
we demonstrate the deliberate tuning of higher-frequency eigenmodes without
affecting the lowest-frequency mode. Thereby, the extension of 2D nanodisks
into the third dimension allows one to engineer their lowest eigenfrequency by
using 3D nanovolcanoes with 30% smaller footprints. The presented nanovolcanoes
can be viewed as multi-mode microwave resonators and 3D building blocks for
nanomagnonics.",2102.03574v1
2022-03-30,Hybrid magnonics for short-wavelength spin waves facilitated by a magnetic heterostructure,"Recent research on hybrid magnonics has been restricted by the long magnon
wavelengths of the ferromagnetic resonance modes. We present an experiment on
the hybridization of 250-nm wavelength magnons with microwave photons in a
multimode magnonic system consists of a planar cavity and a magnetic bilayer.
The coupling between magnon modes in the two magnetic layers, i.e., the uniform
mode in Permalloy (Py) and the perpendicular standing spin waves (PSSWs) in
YIG, serves as an effective means for exciting short-wavelength PSSWs, which is
further hybridized with the photon mode of the microwave resonator. The
demonstrated magnon-photon coupling approaches the superstrong coupling regime,
and can even be achieved near zero bias field.",2203.16310v1
2007-07-24,Baryon resonances and polarization transfer in hyperon photoproduction,"A partial wave analysis is presented of data on photoproduction of hyperons
including single and double polarization observables. The large spin transfer
probability reported by the CLAS collaboration can be successfully described
with an isobar partial wave analysis.",0707.3596v2
2016-08-25,Hybrid surface waves in two-dimensional Rashba-Dresselhaus materials,"We address the electromagnetic properties of two-dimensional electron gas
confined by a dielectric environment in the presence of both Rashba and
Dresselhaus spin-orbit interactions. It is demonstrated that off-diagonal
components of the conductivity tensor resulting from a delicate interplay
between Rashba and Dresselhaus couplings lead to the hybridization of
transverse electric and transverse magnetic surface electromagnetic modes
localized at the interface. We show that the characteristics of these hybrid
surface waves can be controlled by additional intense external off-resonant
coherent pumping.",1608.07128v2
2018-02-12,Zitterbewegung of exciton-polaritons,"Macroscopic wave packets of spin-polarized exciton-polaritons in
two-dimensional microcavities experience the zitterbewegung, the effect
manifested by the appearance of the oscillatory motion of polaritons in the
direction normal to the initial propagation direction. The oscillating
trajectories of exciton-polaritons are adjustable by the control parameters:
the splitting of the longitudinal and transverse exciton-polariton modes, the
wave vector and the width of the resonant cw pump. Our theoretical analysis
supported by the numerical calculations allowed to optimize values of the
control parameters suitable for a direct experimental observation of the
zitterbewegung effect.",1802.04049v1
2004-10-13,Zitterbewegung of electronic wave packets in semiconductor nanostructures,"We study the zitterbewegung of electronic wave packets in III-V zinc-blende
semiconductor quantum wells due to spin-orbit coupling. Our results suggest a
direct experimental proof of this fundamental effect, confirming a
long-standing theoretical prediction. For electron motion in a harmonic quantum
wire, we numerically and analytically find a resonance condition maximizing the
zitterbewegung.",0410321v2
2000-12-27,Evaporative cooling of cesium atoms in the gravito-optical surface trap,"We report on cooling of an atomic cesium gas closely above an
evanescent-wave. Our first evaporation experiments show a temperature reduction
from 10muK down to 300nK along with a gain in phase-space density of almost two
orders of magnitude. In a series of measurements of heating and spin
depolarization an incoherent background of resonant photons in the
evanescent-wave diode laser light was found to be the limiting factor at this
stage.",0012058v1
2007-06-14,Generalized rotating-wave approximation for arbitrarily large coupling,"A generalized version of the rotating-wave approximation for the single-mode
spin-boson Hamiltonian is presented. It is shown that performing a simple
change of basis prior to eliminating the off-resonant terms results in a
significantly more accurate expression for the energy levels of the system. The
generalized approximation works for all values of the coupling strength and for
a wide range of detuning values, and may find applications in solid-state
experiments.",0706.2087v1
2020-12-20,Strong coupling antiferromagnetic resonance with sub-THz cavity fields,"Strong coupling of electromagnetic cavity fields with antiferromagnetic spin
waves in hematite ($\alpha$-Fe$_2$O$_3$) was achieved above room temperature. A
cube of hematite was placed in a metallic tube and transmission was measured,
using a continuous-wave THz spectrometer. Spectra, collected as a function of
temperature, reveal the formation of magnetic polaritons.",2012.10910v2
2013-07-30,Corotation resonance and overstable oscillations in black-hole accretion discs: general-relativistic calculations,"We study the dynamics of spiral waves and oscillation modes in relativistic
rotating discs around black holes. Generalizing the Newtonian theory, we show
that wave absorption can take place at the corotation resonance, where the
pattern frequency of the wave matches the background disc rotation rate. We
derive the general relativistic expression for the disc vortensity (vorticity
divided by surface density), which governs the behaviour of density
perturbation near corotation. Depending on the gradient of the generalized disc
vortensity, corotational wave absorption can lead to the amplification or
damping of the spiral wave. We apply our general theory of relativistic wave
dynamics to calculate the non-axisymmetric inertial-acoustic modes (also called
p-modes) trapped in the inner-most region of a black hole accretion disc.
Because general relativity changes the profiles of the radial epicyclic
frequency and disc vortensity near the inner disc edge close to the black hole,
these p-modes can become overstable under appropriate conditions. We present
the numerical results of the frequencies and growth rates of p-modes for
various black hole spin and model disc parameters (the surface density profile
and sound speed), and discuss their implications for understanding the
enigmatic high-frequency quasi-periodic oscillations observed in black hole
X-ray binaries.",1307.8077v1
1998-01-20,Coherent Resonant Tunneling Through an Artificial Molecule,"Coherent resonant tunneling through an artificial molecule of quantum dots in
an inhomogeneous magnetic field is investigated using an extended Hubbard
model. Both the multiterminal conductance of an array of quantum dots and the
persistent current of a quantum dot molecule embedded in an Aharanov-Bohm ring
are calculated. The conductance and persistent current are calculated
analytically for the case of a double quantum dot and numerically for larger
arrays using a multi-terminal Breit-Wigner type formula, which allows for the
explicit inclusion of inelastic processes. Cotunneling corrections to the
persistent current are also investigated, and it is shown that the sign of the
persistent current on resonance may be used to determine the spin quantum
numbers of the ground state and low-lying excited states of an artificial
molecule. An inhomogeneous magnetic field is found to strongly suppress
transport due to pinning of the spin-density-wave ground state of the system,
and giant magnetoresistance is predicted to result from the ferromagnetic
transition induced by a uniform external magnetic field.",9801201v1
2004-04-27,High Field ESR Study of the pi-d Correlated Organic Conductor lambda-(BETS)2Fe0.6Ga0.4Cl4,"Submillimeter and millimeter wave electron spin resonance (ESR) measurements
of the pi-d correlated organic conductor lambda-(BETS)2Fe0.6Ga0.4Cl4 have been
performed. Antiferromagnetic resonance (AFMR) has been observed in the
insulating antiferromagnetic phase, and its frequency-field dependence can be
reproduced by the biaxial anisotropic AFMR theory. We find that in this alloy
system, the easy-axis is near the b-axis, unlike previous results for the pure
lambda-(BETS)2FeCl4 salts where it is closer to the c*-axis. We have also
observed electron paramagnetic resonance (EPR) in the metallic phase at higher
fields where the g-value is shown to be temperature and frequency dependent for
field applied along the c*-axis. This behavior indicates the existence of
strong pi-d interaction. Our measurements further show the magnetic anisotropy
associated with the anions (the D term in the spin Hamiltonian) is |D|~0.11
cm-1.",0404645v1
2009-05-28,Controlling nuclear spin exchange via optical Feshbach resonances in ${}^{171}$Yb,"Nuclear spin exchange occurs in ultracold collisions of fermionic
alkaline-earth-like atoms due to a difference between s- and p-wave phase
shifts. We study the use of an optical Feshbach resonance, excited on the
${}^1S_0 \to {}^3P_1$ intercombination line of ${}^{171}$Yb, to affect a large
modification of the s-wave scattering phase shift, and thereby optically
mediate nuclear exchange forces. We perform a full multichannel calculation of
the photoassociation resonances and wave functions and from these calculate the
real and imaginary parts of the scattering length. As a figure of merit of this
interaction, we estimate the fidelity to implement a $\sqrt{SWAP}$ entangling
quantum logic gate for two atoms trapped in the same well of an optical
lattice. For moderate parameters one can achieve a gate fidelity of $\sim95% $
in a time of $\sim 50 \mu$s.",0905.4556v1
2011-06-21,Bistability and nonequilibrium transitions in the optically polarized system of cavity polaritons under nanosecond-long resonant excitation,"The polarization dependence of nonequilibrium transitions in a multistable
cavity-polariton system is studied under a nanosecond long resonant optical
excitation at the normal and magic angle incidences with various polarizations
of the pump beam. The temporal correlations between the frequency, intensity,
and optical polarization of the intra-cavity field, which all undergo sharp
threshold-like changes due to the spin dependent interaction of cavity
polaritons, are visualized. The observed dynamics cannot be reproduced within
the conventional semi-classical model based on the Gross-Pitaevskii equations.
To explain the observed phenomena, it is necessary to take into account the
unpolarized exciton reservoir which brings on additional blueshift of bright
excitons, equal in the $\sigma^+$ and $\sigma^-$ polarization components. This
model explains the effect of polarization instability under both pulsed and
continuous wave resonant excitation conditions, consistently with the spin ring
pattern formation that has recently been observed under Gaussian shaped
excitation.",1106.4175v2
2013-04-30,Spin polarization of Ru in superconducting Ba(Fe$_{0.795}$Ru$_{0.205}$)$_2$As$_2$ studied by x-ray resonant magnetic scattering,"We have employed the x-ray resonant magnetic scattering (XRMS) technique at
the Ru $L_2$ edge of the Ba(Fe$_{1-x}$Ru$_x$)$_2$As$_2$ ($x = 0.205$)
superconductor. We show that pronounced resonance enhancements at the Ru $L_2$
edge are observed at the wave vector which is consistent with the
antiferromagnetic propagation vector of the Fe in the undoped BaFe$_2$As$_2$.
We also demonstrate that the XRMS signals at the Ru $L_2$ edge follow the
magnetic ordering of the Fe with a long correlation length, $\xi_{ab} >
2850\pm400$ \AA . Our experimental observation shows that the Ru is
spin-polarized in Ba(Fe$_{1-x}$Ru$_x$)$_2$As$_2$ compounds.",1305.0054v2
2015-07-27,Equilibrium rotation of semiliquid exoplanets and satellites,"A wide range of exoplanet and exomoon models are characterized by a finite
average rigidity and a viscosity much lower than the typical values for
terrestrials. Such semiliquid bodies may or may not have rigid crusts with
permanent figures. Unlike planets with solid mantles and Earth-like rheology,
semiliquid bodies can be captured into stable pseudosynchronous spin resonance,
where the average rate of rotation is higher than the synchronous 1:1
resonance. Two basic conditions are derived for capture of planets with a
triaxial figure into pseudosynchronous rotation, one related to the
characteristic tidal wave number (the product of the tidal frequency by the
Maxwell time), and the other to the orbital eccentricity. If a semiliquid
object does not satisfy either of the two conditions, it is captured into the
synchronous resonance. For nearly axially symmetric bodies, only the first
condition is in place, and the other is much relaxed, so they should
predominantly be pseudosynchronous. It is also pointed out that the equilibrium
pseudosychronous rotation rate can not reach the widely used asymptotic value
from the constant time lag model but is in reality closer to the synchronous
spin.",1507.07383v1
2017-11-27,Calculation of resonances from $K π$ scattering,"We present a determination of the mass, width and coupling of the strange
resonances appearing in pion-kaon scattering below 1.8 GeV, namely the much
debated $K^*_0(800)$ or $\kappa$, the scalar $K^*_0(1430)$, the $K^*(892)$ and
$K^*(1410)$ vectors, the spin-two $K^*_2(1430)$ as well as the spin-three
$K^*_3(1780)$. The parameters of each resonance are determined using a direct
analytic continuation of the pion-kaon partial waves by means of Pad\'e
approximants, thus avoiding any particular model description of their pole
positions and residues, while taking into account the analytic requirements
imposed by dispersion relations.",1711.09688v1
2019-02-06,Observation of Low Temperature Magneto-Mechanic Effects in Crystalline Resonant Phonon Cavities,"We observe magnetic effects in ultra-high quality factor crystalline quartz
Bulk Acoustic Wave resonators at milli-Kelvin temperature. The study reveals
existence of hysteresis loops, jumps and memory effects of acoustical resonance
frequencies. These loops arise as a response to the external magnetic field and
span over few Hertz range for modes with linewidths of about $25$mHz, which
constitute a frequency shift of order 60 linewidths. The effects are broadband
but get stronger towards higher frequencies where both nonlinear effects and
losses are limited by two level systems. This suggests that the observed
effects are due to ferromagnet-like phase of a spin ensemble coupled to
mechanical modes. The observed coupling between mechanical and spin degrees of
freedom in the ultra low loss regime brings new possibilities for the emerging
class of quantum hybrid systems.",1902.02001v2
2021-07-14,Ultrafast Optomagnonics in Ferrimagnetic Multi-Sublattice Garnets,"This review discusses the ultrafast magnetization dynamics within the
gigahertz to terahertz frequency range in ferrimagnetic rare-earth iron garnets
with different substitutions. In these garnets, the roles of spin-orbit and
exchange interactions have been detected using femtosecond laser pulses via the
inverse Faraday effect. The all-optical control of spin-wave and Kaplan-Kittel
exchange resonance modes in different frequency ranges is shown. Generation and
localization of the electric field distribution inside the garnet through the
metal-bound surface plasmon-polariton strongly enhance the amplitude of the
exchange resonance modes. The exchange resonance mode in yttrium iron garnets
was observed using circularly polarized Raman spectroscopy. The results of this
study may be utilized in the development of a wide class of optomagnonic
devices in the gigahertz to terahertz frequency range.",2107.06597v1
2023-09-22,Coherent control of orbital wavefunctions in the quantum spin liquid $Tb_{2}Ti_{2}O_{7}$,"Resonant driving of electronic transitions with coherent laser sources
creates quantum coherent superpositions of the involved electronic states. Most
time-resolved studies have focused on gases or isolated subsystems embedded in
insulating solids, aiming for applications in quantum information. Here, we
demonstrate coherent control of orbital wavefunctions in pyrochlore
$Tb_{2}Ti_{2}O_{7}$, which forms an interacting spin liquid ground state. We
show that resonant excitation with a strong THz pulse creates a coherent
superposition of the lowest energy Tb 4f states before the magnetic
interactions eventually dephase them. The coherence manifests itself as a
macroscopic oscillating magnetic dipole, which is detected by ultrafast
resonant x-ray diffraction. The induced quantum coherence demonstrates coherent
control of orbital wave functions, a new tool for the ultrafast manipulation
and investigation of quantum materials.",2309.12751v1
2023-12-07,Cryogenic platform to investigate strong microwave cavity-spin coupling in correlated magnetic materials,"We present a comprehensive exploration of loop-gap resonators (LGRs) for
electron spin resonance (ESR) studies, enabling investigations into the
hybridization of solid-state magnetic materials with microwave polariton modes.
The experimental setup, implemented in a Physical Property Measurement System
by Quantum Design, allows for ESR spectra at temperatures as low as 2 Kelvin.
The versatility of continuous wave ESR spectroscopy is demonstrated through
experiments on CuSO4.5H2O and MgCr2O4, showcasing the g-tensor and magnetic
susceptibilities of these materials. The study delves into the challenges of
fitting spectra under strong hybridization conditions and underscores the
significance of proper calibration and stabilization. The detailed guide
provided serves as a valuable resource for laboratories interested in exploring
hybrid quantum systems through microwave resonators.",2312.04750v2
2001-07-06,Renormalized mean-field theory of the neutron scattering in cuprate superconductors,"The magnetic excitation spectrum of the t-t'-J-model is studied in mean-field
theory and compared to inelastic neutron-scattering (INS) experiments on YBCO
and BSCCO superconductors. Within the slave-particle formulation the dynamical
spin response is calculated from a renormalized Fermi liquid with an effective
interaction ~J in the magnetic particle--hole channel. We obtain the so-called
41meV resonance at wave vector (pi,pi) as a collective spin-1 excitation in the
d-wave superconducting state. It appears sharp (undamped), if the underlying
Fermi surface is hole-like with a sufficient next-nearest-neighbor hopping
t'<0. The double-layer structure of YBCO or BSCCO is not important for the
resonance to form. The resonance energy \omega_{res} and spectral weight at
optimal doping come out comparable to experiment. The observed qualitative
behavior of \omega_{res} with hole filling is reproduced in the underdoped as
well as overdoped regime. A second, much broader peak becomes visible in the
magnetic excitation spectrum if the 2D wave-vector is integrated over. It is
caused by excitations across the maximum gap, and in contrast to the resonance
its energy is almost independent of doping. At energies above or below
\omega_{res} the commensurate resonance splits into incommensurate peaks,
located off (pi,pi). Below \omega_{res} the intensity pattern is of `parallel'
type and the dispersion relation of incommensurate peaks has a negative
curvature. This is in accordance with recent INS experiments on YBCO.",0107138v1
2004-01-16,Resonant and Non-Resonant Modulated Amplitude Waves for Binary Bose-Einstein Condensates in Optical Lattices,"We consider a system of two Gross-Pitaevskii (GP) equations, in the presence
of an optical-lattice (OL) potential, coupled by both nonlinear and linear
terms. This system describes a Bose-Einstein condensate (BEC) composed of two
different spin states of the same atomic species, which interact linearly
through a resonant electromagnetic field. In the absence of the OL, we find
plane-wave solutions and examine their stability. In the presence of the OL, we
derive a system of amplitude equations for spatially modulated states which are
coupled to the periodic potential through the lowest-order subharmonic
resonance. We determine this averaged system's equilibria, which represent
spatially periodic solutions, and subsequently examine the stability of the
corresponding solutions with direct simulations of the coupled GP equations. We
find that symmetric (equal-amplitude) and asymmetric (unequal-amplitude)
dual-mode resonant states are, respectively, stable and unstable. The unstable
states generate periodic oscillations between the two condensate components,
which is possible only because of the linear coupling between them. We also
find four-mode states, but they are always unstable. Finally, we briefly
consider ternary (three-component) condensates.",0401023v3
2004-12-08,Anisotropy and Field-Dependence of the Spin-Density-Wave Dynamics in the Quasi One-Dimensional Conductor (TMTSF)_2PF_6,"The anisotropic and non-linear transport properties of the quasi
one-dimensional organic conductor (TMTSF)_2PF_6 have been studied by dc,
radiofrequency, and microwave methods. Microwave experiments along all three
axes reveal that collective transport, which is considered to be the
fingerprint of the spin-density-wave condensate, also occurs in the
perpendicular b' direction. The pinned mode resonance is present in the $a$ and
b'-axes response, but not along the least conducting c* direction. The ac-field
threshold, above which the spin-density-wave response is non-linear, strongly
decreases as the temperature drops below 4 K. With increasing strength of the
microwave electric field and of the radiofrequency signal, the pinned mode and
the screened phason loss-peak shift to lower frequencies. In the non-linear
regime, in addition to the phason relaxation mode with Arrhenius-like resistive
decay, an additional mode with very long and temperature-independent relaxation
time appears below 4 K. We attribute the new process to short-wavelength
spin-density-wave excitations associated with discommensurations in a random
commensurate N=4 domain structure.",0412206v1
2019-04-21,Brillouin-Mandelstam Spectroscopy of Stress-Modulated Spatially Confined Spin Waves in Ni Thin Films on Piezoelectric Heterostructures,"We report results of micro-Brillouin-Mandelstam light scattering spectroscopy
of thermal magnons in the two-phase synthetic multiferroic structure consisting
of a piezoelectric (PMN-PT) substrate and a Ni thin film with the thickness of
64 nm. The experimental data reveal the first two modes of the perpendicular
standing spin waves (PSSW) spatially confined across the Ni thin film. A
theoretical analysis of the frequency dependence of the PSSW peaks on the
external magnetic field reveals the asymmetric boundary condition, i.e.
pinning, for variable magnetization at different surfaces of the Ni thin film.
The strain field induced by applying DC voltage to PMN-PT substrate leads to a
down shift of PSSW mode frequency owing to the magneto-elastic effect in Ni,
and corresponding changes in the spin wave resonance conditions. The observed
non-monotonic dependence of the PSSW frequency on DC voltage is related to an
abrupt change of the pinning parameter at certain values of the voltage. The
obtained results are important for understanding the thermal magnon spectrum in
ferromagnetic films and development of the low-power spin-wave devices.",1904.09553v1
2019-05-27,Influence of nonmagnetic dielectric spacers on the spin wave response of one-dimensional planar magnonic crystals,"The one-dimensional planar magnonic crystals are usually fabricated as a
sequence of stripes intentionally or accidentally separated by non-magnetic
spacers. The influence of spacers on shaping the spin wave spectra is complex
and still not completely clarified. We performed the detailed numerical studies
of the one-dimensional single- and bi-component magnonic crystals comprised of
a periodic array of thin ferromagnetic stripes separated by non-magnetic
spacers. We showed that the dynamic dipolar interactions between the stripes
mediated by non-magnetic spacer, even ultra-narrow, significantly shift up the
frequency of the ferromagnetic resonance and simultaneously reduce the spin
wave group velocity, which is manifested by the flattening of the magnonic
band. We attributed these changes in the spectra to the modifications of
dipolar pinning and shape anisotropy both dependent on the width of the spacers
and the thickness of the stripes, as well as to the dynamical magnetic volume
charges formed due to inhomogeneous spin wave amplitude.",1905.11016v4
2023-01-31,Complete identification of spin-wave eigenmodes excited by parametric pumping in YIG microdisks,"We present the parametric excitation of spin-wave modes in YIG micro-disks
via parallel pumping. Their spectroscopy is performed using magnetic resonance
force microscopy (MRFM), while their spatial profiles are determined by
micro-focus Brillouin light scattering (BLS). We observe that almost all the
fundamental eigenmodes of an in-plane magnetized YIG micro-disk, calculated
using a micromagnetic eigenmode solver, can be excited using the parallel
pumping scheme, as opposed to the transverse one. The comparison between the
MRFM and BLS data on one side, and the simulations on the other side, provides
the complete spectroscopic labeling of over 40 parametrically excited modes.
Our findings could be promising for spin-wave-based computation schemes, in
which the amplitudes of a large number of spin-wave modes have to be
controlled.",2301.13468v1
2010-05-06,Low-lying even parity meson resonances and spin-flavor symmetry,"A study is presented of the $s-$wave meson-meson interactions involving
members of the $\rho-$nonet and of the $\pi-$octet. The starting point is an
SU(6) spin-flavor extension of the SU(3) flavor Weinberg-Tomozawa Lagrangian.
SU(6) symmetry breaking terms are then included to account for the physical
meson masses and decay constants, while preserving partial conservation of the
axial current in the light pseudoscalar sector. Next, the $T-$matrix amplitudes
are obtained by solving the Bethe Salpeter equation in coupled-channel with the
kernel built from the above interactions. The poles found on the first and
second Riemann sheets of the amplitudes are identified with their possible
Particle Data Group (PDG) counterparts. It is shown that most of the low-lying
even parity PDG meson resonances, specially in the $J^P=0^+$ and $1^+$ sectors,
can be classified according to multiplets of the spin-flavor symmetry group
SU(6). The $f_0(1500)$, $f_1(1420)$ and some $0^+(2^{++})$ resonances cannot be
accommodated within this SU(6) scheme and thus they would be clear candidates
to be glueballs or hybrids. Finally, we predict the existence of five exotic
resonances ($I \ge 3/2$ and/or $|Y|=2$) with masses in the range 1.4--1.6 GeV,
which would complete the $27_1$, $10_3$, and $10_3^*$ multiplets of
SU(3)$\otimes$SU(2).",1005.0956v2
2016-07-30,Spoof surface plasmon Fabry-Perot open resonators in a surface-wave photonic crystal,"We report on the proposal and experimental realization of a spoof surface
plasmon Fabry-Perot (FP) open resonator in a surface-wave photonic crystal.
This surface-wave FP open resonator is formed by introducing a finite line
defect in a surface-wave photonic crystal. The resonance frequencies of the
surface-wave FP open resonator lie exactly within the forbidden band gap of the
surface-wave photonic crystal and the FP open resonator uses this complete
forbidden band gap to concentrate surface waves within a subwavelength cavity.
Due to the complete forbidden band gap of the surface-wave photonic crystal, a
new FP plasmonic resonance mode that exhibits monopolar features which is
missing in traditional FP resonators and plasmonic resonators is demonstrated.
Near-field response spectra and mode profiles are presented in the microwave
regime to characterize properties of the proposed FP open resonator for spoof
surface plasmons.",1608.00080v1
2006-03-31,Magnetic Excitations of Stripes and Checkerboards in the Cuprates,"We discuss the magnetic excitations of well-ordered stripe and checkerboard
phases, including the high energy magnetic excitations of recent interest and
possible connections to the ""resonance peak"" in cuprate superconductors. Using
a suitably parametrized Heisenberg model and spin wave theory, we study a
variety of magnetically ordered configurations, including vertical and diagonal
site- and bond-centered stripes and simple checkerboards. We calculate the
expected neutron scattering intensities as a function of energy and momentum.
At zero frequency, the satellite peaks of even square-wave stripes are
suppressed by as much as a factor of 34 below the intensity of the main
incommensurate peaks. We further find that at low energy, spin wave cones may
not always be resolvable experimentally. Rather, the intensity as a function of
position around the cone depends strongly on the coupling across the stripe
domain walls. At intermediate energy, we find a saddlepoint at $(\pi,\pi)$ for
a range of couplings, and discuss its possible connection to the ""resonance
peak"" observed in neutron scattering experiments on cuprate superconductors. At
high energy, various structures are possible as a function of coupling strength
and configuration, including a high energy square-shaped continuum originally
attributed to the quantum excitations of spin ladders. On the other hand, we
find that simple checkerboard patterns are inconsistent with experimental
results from neutron scattering.",0603829v3
2022-05-10,"Level-crossing resonances on open atomic transitions in a buffered Cs vapor cell: Linewidth narrowing, high contrast and applications to atomic magnetometry","The ground-state Hanle effect (GSHE) in alkali-metal atomic vapors using a
single circularly polarized wave underlies one of the most robust and simplest
techniques in atomic magnetometry. This effect causes a narrow
(subnatural-width) resonance in the light wave intensity transmitted through a
vapor cell. Usually, GSHE-based sensors operate in the
spin-exchange-relaxation-free (SERF) regime. However, this regime requires a
relatively high temperature of vapors (150 C or higher), leading to a
relatively large heat release and power consumption of the sensor head.
Besides, without applying special measures, SERF regime significantly limits a
dynamic range of measurements. Here, we study a pump-probe scheme involving a
single elliptically polarized wave and a polarimetric detection technique. The
wave is in resonance with two adjacent optical transitions in the cesium D1
line (894.6 nm) owing to their overlapping in presence of a buffer gas (Ne, 130
Torr). Using a small (0.1 cm$^3$) glass vapor cell, we demonstrate a
possibility of observing subnatural-width resonances with a high
contrast-to-width ratio (up to 45 %/mG) under a low-temperature (60 C) regime
of operation thanks to a strong light-induced circular dichroism. Basing on a
$\Lambda$ scheme of atomic energy levels, we obtain explicit analytical
expressions for the line shape. The model reveals a linewidth narrowing effect
due to openness of the scheme. This result is unusual for magneto-optical
atomic spectroscopy because the openness is commonly considered as a
undesirable effect, degrading the resonance characteristics. We estimate a
sensitivity of 1.8 pT/$\surd$Hz with a 60 fT/$\surd$Hz sensitivity in the
photon-shot-noise limit. The results contribute to the theory of GSHE
resonances and can be applied to development of a low-temperature
high-sensitivity miniaturized magnetic field sensor with an extended dynamic
range.",2205.04925v1
2021-05-25,Near-threshold scaling of resonant inelastic collisions at ultralow temperatures,"We show that the cross sections for a broad range of resonant {\it inelastic}
processes accompanied by excitation exchange (such as spin-exchange, F\""orster
resonant, or angular momentum exchange) exhibit an unconventional
near-threshold scaling $E^{\Delta m_{12}}$, where $E$ is the collision energy,
$\Delta m_{12}=m_1'+m_2'-m_1-m_2$, and $m_i$ and $m_i'$ are the initial and
final angular momentum projections of the colliding species ($i=1,\,2$). In
particular, the inelastic cross sections for $\Delta m_{12}=0$ transitions
display an unconventional $E^0$ scaling similar to that of elastic cross
sections, and their rates vanish as $T^{\Delta m_{12}+1/2}$. For collisions
dominated by even partial waves (such as those of identical bosons in the same
internal state) the scaling is modified to $\sigma_\text{inel}\propto E^{\Delta
m_{12} +1} $ if $\Delta m_{12}$ is odd.
  We present accurate quantum scattering calculations that illustrate these
modified threshold laws for resonant spin exchange in ultracold Rb+Rb and
O$_2$+O$_2$ collisions. Our results illustrate that the threshold scaling of
collision cross sections is determined only by the energetics of the underlying
process (resonant vs. exothermic) rather than by whether the internal states of
colliding particles is changed in the collision.",2105.11995v1
2004-01-28,Microscopic mechanisms of magnetization reversal,"Two principal scenarios of magnetization reversal are considered. In the
first scenario all spins perform coherent motion and an excess of magnetic
energy directly goes to a nonmagnetic thermal bath. A general dynamic equation
is derived which includes a tensor damping term similar to the
Bloch-Bloembergen form but the magnetization magnitude remains constant for any
deviation from equilibrium. In the second reversal scenario, the absolute value
of the averaged sample magnetization is decreased by a rapid excitation of
nonlinear spin-wave resonances by uniform magnetization precession. We have
developed an analytic k-space micromagnetic approach that describes this entire
reversal process in an ultra-thin soft ferromagnetic film for up to 90^{o}
deviation from equilibrium. Conditions for the occurrence of the two scenarios
are discussed.",0401590v1
1993-08-20,Relativistic Covariant Equal-Time Equation For Quark-Diquark System,"Relativistic three-dimensional quasipotential (equal-time) equations are
considered, which describe bound states of fermion and boson of spin S=0 or
S=1. The spin structure of the interaction quasipotentials in such systems is
studied, and corresponding partial-wave equation for the simplest case is
obtained. Such equations can be used in calculations of energy spectra, decay
rates and structure functions of quark-diquark systems (nucleons and their
resonances) as well as for description of ($\pi\mu$)- atom.",9308305v1
2007-03-20,Baryon-baryon and baryon-antibaryon interaction amplitudes in the spin--momentum operator expansion method,"Partial wave scattering amplitudes in baryon-baryon and baryon-antibaryon
collisions and amplitudes for the production and decay of baryon resonances are
constructed in the framework of the spin-momentum operator expansion method.
The approach is relativistically invariant and it allows us to perform combined
analyses of different reactions imposing analyticity and unitarity directly.
The role of final state interactions (triangle and box diagrams) is discussed.",0703216v2
1998-04-09,Relativistic Spin-Flavor States in Light Front Dynamics,"Orthonormal spin-flavor wave functions of Lorentz covariant quark models of
the Bakamjian-Thomas type are constructed for nucleon resonances. Three
different bases are presented. The manifestly Lorentz covariant Dirac-Melosh
basis is related to the Pauli-Melosh basis and the symmetrized Bargmann-Wigner
basis that are manifestly orthogonal.",9804021v1
2008-07-28,High Field ESR in the Two-Dimensional Triangular Lattice Antiferromagnet NiGa2S4,"In this Letter, we report the results of ESR measurements in high magnetic
fields up to about 53 T on single crystals of NiGa2S4 to clarify the spin
dynamics in more detail. We have found that the dynamics of Z2 vortices affects
the temperature dependence of the ESR absorption linewidth and the frequency
dependence of the ESR resonance fields at 1.3 K is well explained by a
conventional spin wave theory. These results suggest an occurrence of Z2
vortex-induced topological transition.",0807.4438v2
2008-10-10,The magnetohydrodynamics model of twin kilohertz QPOs in LMXBs,"We suggest an explanation for the twin kilohertz quasi-periodic oscillations
(kHz QPOs) in low-mass X-ray binaries (LMXBs) based on magnetohydrodynamics
(MHD) oscillation modes in neutron star magnetospheres. Including the effect of
the neutron star spin, we derive several MHD wave modes by solving the
dispersion equations, and propose that the coupling of the two resonant MHD
modes may lead to the twin kHz QPOs. This model naturally relates the upper,
lower kHz QPO frequencies with the spin frequencies of the neutron stars, and
can well account for the measured data of six LMXBs.",0810.1797v1
2010-07-28,Temporally multiplexed quantum repeaters with atomic gases,"We propose a temporally multiplexed version of the Duan-Lukin-Cirac-Zoller
(DLCZ) quantum repeater protocol using controlled inhomogeneous spin broadening
in atomic gases. A first analysis suggests that the advantage of multiplexing
is negated by noise due to spin wave excitations corresponding to unobserved
directions of Stokes photon emission. However, this problem can be overcome
with the help of a moderate-finesse cavity which is in resonance with Stokes
photons, but invisible to the anti-Stokes photons. Our proposal promises
greatly enhanced quantum repeater performance with atomic gases.",1007.5028v1
2010-12-08,Optically erasing disorder in semiconductor microcavities with dynamic nuclear polarization,"The mean squared value of the photonic disorder is found to be reduced by a
factor of 100 in a typical GaAs based microcavity, when exposed to a circularly
polarized continuous wave optical pump without any special spatial patterning.
Resonant excitation of the cavity mode excites a spatially non-uniform
distribution of spin-polarized electrons, which depends on the photonic
disorder profile. Electrons transfer spin to nuclei via the hyperfine contact
interaction, inducing a long-living Overhauser magnetic field able to modify
the potential of exciton-polaritons.",1012.1732v2
2011-01-18,Temperature-dependent spin resonance energy in iron pnictides and multiband s\pm Eliashberg theory,"The phenomenology of iron-pnictides superconductors can be explained in the
framework of a three bands s\pm wave Eliashberg theory with only two free
parameters plus a feedback effect i.e. the effect of the condensate on the
antiferromagnetic spin fluctuactions responsible of the superconductivity in
these compounds. I have examined the experimental data of four materials:
LaFeAsO1-xFx, SmFeAsO1-xFx, Ba1-xKxFe2As2, and Ba(FexCo1-x)2As2 and I have
found that it is possible to reproduce the experimental critical temperature
and gap values in a moderate strong-coupling regime: ltot about 1.7-2.0.",1101.3473v2
2013-01-15,Manipulation of Ferromagnets via the Spin-Selective Optical Stark Effect,"We investigate the non-resonant all-optical switching of magnetization. We
treat the inverse Faraday effect (IFE) theoretically in terms of the
spin-selective optical Stark effect for linearly or circularly polarized light.
In the dilute magnetic semiconductors (Ga,Mn)As, strong laser pulses below the
band gap induce effective magnetic fields of several teslas in a direction
which depends on the magnetization and light wave vectors. Our theory
demonstrates that the polarized light catalyzes the angular momentum transfer
between lattice and the magnetization.",1301.3481v2
2020-01-19,Chiral Coupling to Magnetodipolar Radiation,"We review and extend the theory of chiral pumping of spin waves by
magnetodipolar stray fields that generate unidirectional spin currents and
asymmetric magnon densities. We illustrate the physical principles by two kinds
of chiral excitations of magnetic films, i.e., by the evanescent Oersted field
of a narrow metallic stripline with an AC current bias and a magnetic nanowire
under ferromagnetic resonance.",2001.06821v2
2022-12-22,Spin wave dispersion of ultra-low damping hematite ($α\text{-Fe}_2\text{O}_3$) at GHz frequencies,"Low magnetic damping and high group velocity of spin waves (SWs) or magnons
are two crucial parameters for functional magnonic devices. Magnonics research
on signal processing and wave-based computation at GHz frequencies focussed on
the artificial ferrimagnetic garnet Y$_3$Fe$_5$O$_{12}$ (YIG) so far. We report
on spin-wave spectroscopy studies performed on the natural mineral hematite
($\alpha\text{-Fe}_2\text{O}_3$) which is a canted antiferromagnet. By means of
broadband GHz spectroscopy and inelastic light scattering, we determine a
damping coefficient of $1.1\times10^{-5}$ and magnon group velocities of a few
10 km/s, respectively, at room temperature. Covering a large regime of wave
vectors up to $k\approx 24~{\rm rad}/\mu$m, we find the exchange stiffness
length to be relatively short and only about 1 \r{A}. In a small magnetic field
of 30 mT, the decay length of SWs is estimated to be 1.1 cm similar to the best
YIG. Still, inelastic light scattering provides surprisingly broad and partly
asymmetric resonance peaks. Their characteristic shape is induced by the large
group velocities, low damping and distribution of incident angles inside the
laser beam. Our results promote hematite as an alternative and sustainable
basis for magnonic devices with fast speeds and low losses based on a stable
natural mineral.",2212.11887v2
2009-09-08,Giant Slow Wave Resonance for Light Amplification and Lasing,"We apply the idea of giant slow wave resonance associated with a degenerate
photonic band edge to gain enhancement of active media. This approach allows to
dramatically reduce the size of slow wave resonator while improving its
performance as gain enhancer for light amplification and lasing. It also allows
to reduce the lasing threshold of the slow wave optical resonator by at least
an order of magnitude.",0909.1393v1
2022-03-02,Atomic-Scale Spin-Wave Polarizer Based on a Sharp Antiferromagnetic Domain Wall,"We theoretically study the scattering of spin waves from a sharp domain wall
in an antiferromagnetic spin chain. While the continuum model for an
antiferromagnetic material yields the well-known result that spin waves can
pass through a wide domain wall with no reflection, here we show that, based on
the discrete spin Hamiltonian, spin waves are generally reflected by a domain
wall with a reflection coefficient that increases as the domain-wall width
decreases. Remarkably, we find that, in the interesting case of an atomically
sharp domain wall, the reflection of spin waves exhibits strong dependence on
the state of circular polarization of the spin waves, leading to mainly
reflection for one polarization while permitting partial transmission for the
other, thus realizing an atomic-scale spin-wave polarizer. The polarization of
the transmitted spin wave depends on the orientation of the spin in the sharp
domain wall, which can be controlled by an external field or spin torque. Our
utilization of a sharp antiferromagnetic domain wall as an atomic-scale
spin-wave polarizer leads us to envision that ultra-small magnetic solitons
such as domain walls and skyrmions may enable realizations of atomic-scale
spin-wave scatterers with useful functionalities.",2203.01453v1
2006-11-27,Spin-dependent electronic structure of transition-metal atomic chains adsorbed on single-wall carbon nanotubes,"We present a systematic study of the electronic and magnetic properties of
transition-metal (TM) atomic chains adsorbed on the zigzag single-wall carbon
nanotubes (SWNTs). We considered the adsorption on the external and internal
wall of SWNT and examined the effect of the TM coverage and geometry on the
binding energy and the spin polarization at the Fermi level. All those adsorbed
chains studied have ferromagnetic ground state, but only their specific types
and geometries demonstrated high spin polarization near the Fermi level. Their
magnetic moment and binding energy in the ground state display interesting
variation with the number of $d-$electrons of the TM atom. We also show that
specific chains of transition metal atoms adsorbed on a SWNT can lead to
semiconducting properties for the minority spin-bands, but semimetallic for the
majority spin-bands. Spin-polarization is maintained even when the underlying
SWNT is subjected to high radial strain. Spin-dependent electronic structure
becomes discretized when TM atoms are adsorbed on finite segments of SWNTs.
Once coupled with non-magnetic metal electrodes, these magnetic needles or
nanomagnets can perform as spin-dependent resonant tunnelling devices. The
electronic and magnetic properties of these nanomagnets can be engineered
depending on the type and decoration of adsorbed TM atom as well as the size
and symmetry of the tube. Our study is performed by using first-principles
pseudopotential plane wave method within spin-polarized Density Functional
Method.",0611670v1
2015-06-14,Few-second-long correlation times in a quantum dot nuclear spin bath probed by frequency-comb NMR spectroscopy,"One of the key challenges in spectroscopy is inhomogeneous broadening that
masks the homogeneous spectral lineshape and the underlying coherent dynamics.
A variety of techniques including four-wave mixing and spectral hole-burning
are used in optical spectroscopy while in nuclear magnetic resonance (NMR)
spin-echo is the most common way to counteract inhomogeneity. However, the
high-power pulses used in spin-echo and other sequences often create spurious
dynamics obscuring the subtle spin correlations that play a crucial role in
quantum information applications. Here we develop NMR techniques that allow the
correlation times of the fluctuations in a nuclear spin bath of individual
quantum dots to be probed. This is achieved with the use of frequency comb
excitation which allows the homogeneous NMR lineshapes to be measured avoiding
high-power pulses. We find nuclear spin correlation times exceeding 1 s in
self-assembled InGaAs quantum dots - four orders of magnitude longer than in
strain-free III-V semiconductors. The observed freezing of the nuclear spin
fluctuations opens the way for the design of quantum dot spin qubits with a
well-understood, highly stable nuclear spin bath.",1506.04412v1
2016-05-09,Electron doping evolution of the magnetic excitations in NaFe$_{1-x}$Co$_x$As,"We use time-of-flight (ToF) inelastic neutron scattering (INS) spectroscopy
to investigate the doping dependence of magnetic excitations across the phase
diagram of NaFe$_{1-x}$Co$_x$As with $x=0, 0.0175, 0.0215, 0.05,$ and $0.11$.
The effect of electron-doping by partially substituting Fe by Co is to form
resonances that couple with superconductivity, broaden and suppress low energy
($E\le 80$ meV) spin excitations compared with spin waves in undoped NaFeAs.
However, high energy ($E> 80$ meV) spin excitations are weakly Co-doping
dependent. Integration of the local spin dynamic susceptibility
$\chi^{\prime\prime}(\omega)$ of NaFe$_{1-x}$Co$_x$As reveals a total
fluctuating moment of 3.6 $\mu_B^2$/Fe and a small but systematic reduction
with electron doping. The presence of a large spin gap in the Co-overdoped
nonsuperconducting NaFe$_{0.89}$Co$_{0.11}$As suggests that Fermi surface
nesting is responsible for low-energy spin excitations. These results parallel
Ni-doping evolution of spin excitations in BaFe$_{2-x}$Ni$_x$As$_2$, confirming
the notion that low-energy spin excitations coupling with itinerant electrons
are important for superconductivity, while weakly doping dependent high-energy
spin excitations result from localized moments.",1605.02695v1
2019-01-04,Spin-flavor oscillations of Dirac neutrinos in matter under the influence of a plane electromagnetic wave,"We study oscillations of Dirac neutrinos in background matter and a plane
electromagnetic wave. First, we find the new exact solution of the Dirac-Pauli
equation for a massive neutrino with the anomalous magnetic moment
electroweakly interacting with matter under the influence of a plane
electromagnetic wave with the circular polarization. We use this result to
describe neutrino spin oscillations in the external fields in question. Then we
consider several neutrino flavors and study neutrino spin-flavor oscillations
in this system. For this purpose we formulate the initial condition problem and
solve it accounting for the considered external fields. We derive the
analytical expressions for the transition probabilities of spin-flavor
oscillations for different types of neutrino magnetic moments. These analytical
expressions are compared with the numerical solutions of the effective
Schr\""odinger equation and with the findings of other authors. In particular,
we reveal that a resonance in neutrino spin-flavor oscillations in the
considered external fields cannot happen contrary to the previous claims.
Finally, we briefly discuss some possible astrophysical applications.",1901.01022v2
2019-10-04,Spin fluctuation anisotropy as a probe of orbital-selective hole-electron quasiparticle excitations in detwinned Ba(Fe1-xCox)2As2,"We use inelastic neutron scattering to study spin excitation anisotropy in
mechanically detwinned Ba(Fe1-xCox)2As2 with x = 0.048 and 0.054. Both samples
exhibit a tetragonal-to-orthorhombic structural transition at Ts, a collinear
static antiferromagnetic (AF) order at wave vector Q1 = QAF = (1, 0) below the
Neel temperature TN, and superconductivity below Tc (Ts > TN > Tc). In the high
temperature paramagnetic tetragonal phase (T > Ts), spin excitations centered
at Q1 and Q2 = (0, 1) are gapless and have four-fold (C4) rotational symmetry.
On cooling to below TN but above Tc, spin excitations become highly
anisotropic, developing a gap at Q2 but still are gapless at Q1. Upon entering
into the superconducting state, a neutron spin resonance appears at Q1 with no
magnetic scattering at Q2. By comparing these results with those from angle
resolved photoemission spectroscopy experiments, we conclude that the
anisotropic shift of the dyz and dxz bands in detwinned Ba(Fe1-xCox)2As2 below
Ts is associated with the spin excitation anisotropy, and the
superconductivity-induced resonance arises from the electron-hole Fermi surface
nesting of quasiparticles with the dyz orbital characters.",1910.01871v1
2004-11-12,Resonance spin filter,"A design of the resonance spin finter is suggested in form of a quantum well
with three quantum wires attached. Explicit formula is suggested for
transmission coefficients accross the well in terms of the resonance
eigenfunction of the Schredinger operator on the well with Rashba spin-orbital
interaction.",0411354v1
2012-06-08,Weak Spin Fluctuation with Finite Wave Vector and Superconducting Gap Symmetry in KxFe2-ySe2: 77Se Nuclear Magnetic Resonance,"We report $^{77}$Se-nuclear magnetic resonance (NMR) results down to
sufficiently low temperatures under magnetic fields parallel to both the
$ab$-plane and the c-axis in a paramagnetic/superconducting (PM/SC) phase of
K$_x$Fe$_{2-y}$Se$_2$. The observation of anisotropy in the orbital part of the
Knight shift results in the anisotropy of its spin part increasing on
approaching the transition temperature. The anisotropy of the Korringa relation
suggests the presence of the weak spin fluctuations with a finite wave vector
$\bm{q}$, which induce the magnetic fluctuations along the ab-plane at the Se
site. Such fluctuations do not correspond to the stripe $(\pi,0)$ correlation
of the Fe moment observed in many Fe-based superconductors, and are not
contradictory to weak $(\pi,\pi)$ correlations. The nuclear spin-lattice
relaxation rate $1/T_1$ shows a field-independent $T_1T \sim const.$ behavior
at low temperatures for $H \parallel ab$, which is attributed to the nonzero
density of states at the Fermi level and can be explained by the sign-changing
order parameter even for nodeless gaps. The temperature dependence of $1/T_1$
is reproduced well by nodeless models with two isotropic gaps or a single
anisotropic gap. The obtained gap magnitude in the isotropic two-gap model is
comparable to those obtained in the angle-resolved photoemission spectroscopy
experiments.",1206.1756v2
2024-04-09,High-Fidelity CZ Gates in Double Quantum Dot -- Circuit QED Systems Beyond the Rotating-Wave Approximation,"Semiconductor double quantum dot (DQD) qubits coupled via superconducting
microwave resonators provide a powerful means of long-range manipulation of the
qubits' spin and charge degrees of freedom. Quantum gates can be implemented by
parametrically driving the qubits while their transition frequencies are
detuned from the resonator frequency. Long-range two-qubit CZ gates have been
proposed for the DQD spin qubit within the rotating-wave approximation (RWA).
Rapid gates demand strong coupling, but RWA breaks down when coupling strengths
become significant relative to system frequencies. Therefore, understanding the
detrimental impact of time-dependent terms ignored by RWA is critical for
high-fidelity operation. Here, we go beyond RWA to study CZ gate fidelity for
both DQD spin and charge qubits. We propose a novel parametric drive on the
charge qubit that produces fewer time-dependent terms and show that it
outperforms its spin counterpart. We find that drive amplitude - a parameter
dropped in RWA - is critical for optimizing fidelity and map out high-fidelity
regimes. Our results demonstrate the necessity of going beyond RWA in
understanding how long-range gates can be realized in DQD qubits, with charge
qubits offering considerable advantages in high-fidelity operation.",2404.06187v1
1998-11-03,Slave Boson Approach to The Neutron Scattering in YBCO Superconductors,"The evolution of the so-called `41meV resonance' in the magnetic response of
YBCO cuprates is studied with slave-boson theory for the t-t'-J-model. The
resonance appears as a collective spin fluctuation in the d-wave
superconducting (SC) state. It is undamped at optimal doping due to a threshold
in the excitation energies of particle--hole pairs with relative wave vector
(pi,pi). When hole filling is reduced, the resonance moves to lower energies
and broadens. Below the resonance energy we find a crossover to an
incommensurate response in agreement with a recent experiment on
YBa_2CU_3O_6.6. We show that dynamic nesting in the d-wave SC state causes this
effect.",9811038v2
2003-07-09,Resonant Enhancement of Inelastic Light Scattering in the Fractional Quantum Hall Regime at $ν=1/3$,"Strong resonant enhancements of inelastic light scattering from the long
wavelength inter-Landau level magnetoplasmon and the intra-Landau level spin
wave excitations are seen for the fractional quantum Hall state at $\nu = 1/3$.
The energies of the sharp peaks (FWHM $\lesssim 0.2meV$) in the profiles of
resonant enhancement of inelastic light scattering intensities coincide with
the energies of photoluminescence bands assigned to negatively charged exciton
recombination. To interpret the observed enhancement profiles, we propose
three-step light scattering mechanisms in which the intermediate resonant
transitions are to states with charged excitonic excitations.",0307220v1
2003-03-28,Dilepton decays of nucleon resonances and dilepton production cross sections in proton-proton collisions,"Relativistic, kinematically complete phenomenological expressions for the
dilepton decay rates of nucleon resonances with arbitrary spin and parity are
derived in terms of the magnetic, electric, and Coulomb transition form
factors. The dilepton decay rates of the nucleon resonances with masses below 2
GeV are estimated using the extended vector meson dominance (eVMD) model for
the transition form factors. The model provides an unified description of the
photo- and electroproduction data and of the vector meson and dilepton decays
of the nucleon resonances. The constraints on the transition form factors from
the quark counting rules are taken into account explicitly. The remaining
parameters of the model are fixed by fitting the available photo- and
electroproduction data and using results of the multichannel partial-wave
analysis of the $\pi N$ scattering. The results are used to describe dilepton
spectra measured at BEVALAC in proton-proton collisions.",0303071v1
2004-07-22,Vector meson angular distributions in proton-proton collisions,"The resonance model is used to analyze the omega- and phi-meson angular
distributions in proton-proton collisions at sqrt{s} = 2.83 and 2.98 GeV. The
assumption of dominant contributions from N^*(1720)3/2+ and N^*(1900)3/2+
resonances which both have, according to the pi N scattering multichannel
partial-wave analysis and/or quark models predictions, dominant p_{1/2} N-omega
decay modes yields the right pattern of the omega angular distribution at
sqrt{s} = 2.83 GeV. The angular distribution at sqrt{s} = 2.98 GeV can be
reproduced assuming the dominance of N^*(2000)5/2+ and N^*(1900)3/2+. The
experimental phi-meson angular distributions do not shown any asymmetry which
requires the existence of a massive negative-parity spin-half resonance. This
resonance could be identified with the N^*(2090)1/2-.",0407075v1
2007-04-04,Non-resonant and Resonant X-ray Scattering Studies on Multiferroic TbMn2O5,"Comprehensive x-ray scattering studies, including resonant scattering at Mn
L-edge, Tb L- and M-edges, were performed on single crystals of TbMn2O5. X-ray
intensities were observed at a forbidden Bragg position in the ferroelectric
phases, in addition to the lattice and the magnetic modulation peaks.
Temperature dependences of their intensities and the relation between the
modulation wave vectors provide direct evidences of exchange striction induced
ferroelectricity. Resonant x-ray scattering results demonstrate the presence of
multiple magnetic orders by exhibiting their different temperature dependences.
The commensurate-to-incommensurate phase transition around 24 K is attributed
to discommensuration through phase slipping of the magnetic orders in spin
frustrated geometries. We proposed that the low temperature incommensurate
phase consists of the commensurate magnetic domains separated by anti-phase
domain walls which reduce spontaneous polarizations abruptly at the transition.",0704.0533v1
2009-12-19,Microscopic study of the isoscalar giant resonances in 208Pb induced by inelastic alpha scattering,"The energetic beam of (spin and isospin zero) $\alpha$-particles remains a
very efficient probe for the nuclear isoscalar giant resonances. In the present
work, a microscopic folding model study of the isoscalar giant resonances in
$^{208}$Pb induced by inelastic \aPb scattering at $E_{\rm lab}=240$ and 386
MeV has been performed using the (complex) CDM3Y6 interaction and nuclear
transition densities given by both the collective model and Random Phase
Approximation (RPA) approach. The fractions of energy weighted sum rule around
the main peaks of the isoscalar monopole, dipole and quadrupole giant
resonances were probed in the Distorted Wave Born Approximation analysis of
inelastic \aPb scattering using the double-folded form factors given by
different choices of the nuclear transition densities. The energy distribution
of the $E0, E1$ and $E2$ strengths given by the multipole decomposition
{analyses} of the \aap data under study are compared with those predicted by
the RPA calculation.",0912.3858v1
2012-07-31,Three-body properties of low-lying $^{12}$Be resonances,"We compute the three-body structure of the lowest resonances of $^{12}$Be
considered as two neutrons around an inert $^{10}$Be core. This is an extension
of the bound state calculations of $^{12}$Be into the continuum spectrum. We
investigate the lowest resonances of angular momenta and parities, $0^{\pm}$,
$1^{-}$ and $2^{+}$. Surprisingly enough, they all are naturally occurring in
the three-body model. We calculate bulk structure dominated by small distance
properties as well as decays determined by the asymptotic large-distance
structure. Both $0^{+}$ and $2^{+}$ have two-body $^{10}$Be-neutron d-wave
structure, while $1^{-}$ has an even mixture of $p$ and d-waves. The
corresponding relative neutron-neutron partial waves are distributed among $s$,
$p$, and d-waves. The branching ratios show different mixtures of one-neutron
emission, three-body direct, and sequential decays. We argue for spin and
parities, $0^{+}$, $1^{-}$ and $2^{+}$, to the resonances at 0.89, 2.03, 5.13,
respectively. The computed structures are in agreement with existing reaction
measurements.",1207.7191v1
2018-04-03,Optical properties of coupled silicon nanowires and unusual mechanical inductions,"A recent study of the photonic coupling between metallic nanowires has
revealed new degrees of freedom in the system. Unexpected spin torques were
induced on dimers when illuminated with linearly polarized plane-waves. As
near-field observables, the spectra of torques showed more resolved resonances
than typical far-field spectra. Here the study is extended to silicon dimers.
Strong forces and torques are exerted by light under both polarizations s and
p, contrary to plasmonic systems where the resonant strong forces are found
only for p-polarization. The systems made of high-dielectric possess volume
resonances that induce the forces differently than in plasmonic systems, which
have surface resonances. The asymmetry in strong near-fields is responsible for
the unusual mechanics of the system. Some consequences of that may include the
breaking of the action-reaction principle or the appearance of pulling forces.
  The numerical study is based on an exact method. The work is thought for the
design of nanorotators and nanodetectors. It suggests a new viewpoint about
optical forces: the resultant dynamics of topological variations of
electromagnetic fields.",1804.01162v1
1999-08-06,Resonant Structure of $τ\to 3ππ^{0}ν_τ$ and $τ\to ωπν_τ$ Decays,"The resonant structure of the four pion final state in the decay $\tau \to
3\pi\pi^0\nu_\tau$ is analyzed using 4.27 million $\tau^+\tau^-$ pairs
collected by the CLEO II experiment. We search for second class currents in the
decay $\tau \to \omega\pi\nu_\tau$ using spin-parity analysis and establish an
upper limit on the non-vector current contribution. The mass and width of the
$\rho'$ resonance are extracted from a fit to the $\tau \to \omega\pi\nu_\tau$
spectral function. A partial wave analysis of the resonant structure of the
$\tau \to 3\pi\pi^0\nu_\tau$ decay is performed; the spectral decomposition of
the four pion system is dominated by the $\omega\pi$ and $a_1 \pi$ final
states.",9908024v1
2008-11-11,Relativistic Quark-Model Results for Baryon Ground and Resonant States,"Latest results from a study of baryon ground and resonant states within
relativistic constituent quark models are reported. After recalling some
typical spectral properties, the description of ground states, especially with
regard to the nucleon and hyperon electromagnetic structures, is addressed. In
the following, recent covariant predictions for pion, eta, and kaon partial
decay widths of light and strange baryon resonances below 2 GeV are summarized.
These results exhibit a characteristic pattern that is distinct from
nonrelativistic or relativized decay studies performed so far. Together with a
detailed analysis of the spin, flavor, and spatial structures of the wave
functions, it supports a new and extended classification scheme of baryon
ground and resonant states into SU(3) flavor multiplets.",0811.1752v1
2008-12-17,Observation of interspecies Feshbach resonances in an ultracold Rb-Cs mixture,"We report on the observation of interspecies Feshbach resonances in an
ultracold, optically trapped mixture of Rb and Cs atoms. In a magnetic field
range up to 300 G we find 23 interspecies Feshbach resonances in the lowest
spin channel and 2 resonances in a higher channel of the mixture. The
extraordinarily rich Feshbach spectrum suggests the importance of different
partial waves in both the open and closed channels of the scattering problem
along with higher-order coupling mechanisms. Our results provide, on one hand,
fundamental experimental input to characterize the Rb-Cs scattering properties
and, on the other hand, identify possible starting points for the association
of ultracold heteronuclear RbCs molecules.",0812.3287v1
2022-04-06,Power transfer in magnetoelectric resonators,"We derive an analytical model for the power transfer in a magnetoelectric
film bulk acoustic resonator consisting of a piezoelectric--magnetostrictive
bilayer. The model describes the dynamic magnetostrictive influence on the
elastodynamics via an effective frequency-dependent stiffness constant. This
allows for the calculation of both the magnetic and elastic power absorption in
the resonator as well as of its energy efficiency when such a resonator is
considered as a magnetic transducer. The model is then applied to example
systems consisting of piezoelectric ScAlN and magnetostrictive CoFeB, Ni, or
Terfenol-D layers.",2204.03072v2
1998-03-10,Spin-Alignment and Quasi-Molecular Resonances in Heavy-Ion Collision,"Fragment-fragment-$\gamma$ triple coincidence measurements of the
$^{28}$Si~$+$~$^{28}$Si reaction at E$_{\rm c.m.}$~=~55.8 MeV, carefully chosen
to populate a well known quasi-molecular resonance in $^{56}$Ni, have been
performed at the VIVITRON tandem facility by using the Eurogam Phase~II
$\gamma$-ray spectrometer. In the $^{28}$Si~$+$~$^{28}$Si reaction, the
resonant behavior of the $^{28}$Si $+$ $^{28}$Si exit-channel is clearly
observed by the present fragment-fragment coincidence data. The more unexpected
result is the spin disalignment of the $^{28}$Si $+$ $^{28}$Si resonance. This
has been demonstrated first by the measured angular distributions of the
elastic 0$^{+}$, inelastic 2$^{+}$ and mutual excitation channels
2$^{+}-2^{+}$, which are dominated by a unique and pure partial wave with L =
38 ${\rm \hbar}$, and has been confirmed by measuring their particle-$\gamma$
angular correlations with Eurogam Phase II. The spin disalignment supports new
molecular model predictions, in which the observed resonance would correspond
to the ''Butterfly mode''. A discussion concerning the {\it spin alignment and
spin disalignment} for different systems : $^{12}$C~$+$~$^{12}$C,
$^{24}$Mg~$+$~$^{24}$Mg and $^{28}$Si~$+$~$^{28}$Si will be given.}",9803005v1
2010-04-07,Microscopic Model of Cuprate Superconductivity,"We present a model for cuprate superconductivity based on the identification
of an experimentally detected ""local superconductor"" as a charge 2 fermion
pairing in a circular, stationary density wave. This wave acts like a highly
correlated local ""boson"" satisfying a modified Cooper problem with additional
correlation stabilization relative to the separate right- and left-handed
density waves composing it. This local ""boson"" could be formed in a two-bound
roton-like manner; it has Fermion statistics. Delocalized superconductive
pairing (superconductivity) is achieved by a Feshbach resonance of two unpaired
holes (electrons) resonating with a virtual energy level of the bound pair
state of the local ""boson"" as described by the Boson-Fermion-Gossamer (BFG)
model. The spin-charge order interaction offers an explanation for the overall
shape of the superconducting dome as well a microscopic basis for the cuprate
superconducting transition temperatures. An explanation of the correlation of
superconducting transition temperature with experimental inelastic neutron and
electron Raman scattering is proposed, based on the energy of the virtual bound
pair. These and other modifications discussed suggest a microscopic explanation
for the entire cuprate superconductivity dome shape.",1004.1100v1
2018-02-28,Resonant magneto-acoustic switching: influence of Rayleigh wave frequency and wavevector,"We show on in-plane magnetized thin films that magnetization can be switched
efficiently by 180 degrees using large amplitude Rayleigh waves travelling
along the hard or easy magnetic axis. Large characteristic filament-like
domains are formed in the latter case. Micromagnetic simulations clearly
confirm that this multi-domain configuration is compatible with a resonant
precessional mechanism. The reversed domains are in both geometries several
hundreds of \mu m^2, much larger than has been shown using spin transfer
torque- or field-driven precessional switching. We show that surface acoustic
waves can travel at least 1mm before addressing a given area, and can interfere
to create magnetic stripes that can be positionned with a sub-micronic
precision.",1802.10318v1
2023-09-01,"Rieger, Schwabe, Suess-de Vries: The Sunny Beats of Resonance","We propose a self-consistent explanation of Rieger-type periodicities, the
Schwabe cycle, and the Suess-de Vries cycle of the solar dynamo in terms of
resonances of various wave phenomena with gravitational forces exerted by the
orbiting planets. Starting on the high-frequency side, we show that the
two-planet spring tides of Venus, Earth and Jupiter are able to excite
magneto-Rossby waves which can be linked with typical Rieger-type periods. We
argue then that the 11.07-year beat period of those magneto-Rossby waves
synchronizes an underlying conventional $\alpha-\Omega$-dynamo, by periodically
changing either the field storage capacity in the tachocline or some portion of
the $\alpha$-effect therein. We also strengthen the argument that the Suess-de
Vries cycle appears as an 193-year beat period between the 22.14-year Hale
cycle and a spin-orbit coupling effect related with the 19.86-year rosette-like
motion of the Sun around the barycenter.",2309.00666v2
2002-11-14,Electron Spin Polarization in Resonant Interband Tunneling Devices,"We study spin-dependent interband resonant tunneling in double-barrier
InAs/AlSb/ GaMnSb heterostructures. We demonstrate that these structures can be
used as spin filters utilizing spin-selective tunneling of electrons through
the light-hole resonant channel. High densities of the spin polarized electrons
injected into bulk InAs make spin resonant tunneling devices a viable
alternative for injecting spins into a semiconductor. Another striking feature
of the proposed devices is the possibility of inducing additional resonant
channels corresponding to the heavy holes. This can be implemented by
saturating the in-plane magnetization in the quantum well.",0211300v1
2019-11-05,Computational Study of Electron Paramagnetic Resonance Spectra for Li and Ga Vacancies in LiGaO2,"A computational study of the Electron Paramagnetic Resonance (EPR)
$g$-tensors and hyperfine tensors of Li and Ga vacancies in LiGaO$_2$ is
presented. Density Functinal Theory (DFT) calculations are carried out of the
Ga and Li vacancies using the DFT+U approach in the charge states which carry
an unpaired spin. In both vacancies the hole is located on one oxygen
$p$-orbital adjacent to the vacancy. Apical and different basal plane O are
considered. The magnetic resonance parameters of the defects are determined
using the Gauge Including Projector Augmented Wave (GIPAW) method. The EPR
spectra of $V_\mathrm{Ga}^{2-}$ is characterized by a quasi-isotropic
superhyperfine (SHF) interaction with one Ga nucleus and for the apical O spin
gives a $g$-tensor with maximum oriented along the bond direction from that O
to its other Ga neighbor. For $V_\mathrm{Li}^0$ there is a quasi-isotropic SHF
interaction with two Ga nuclei and the $g$-tensor maximum is along ${\bf c}$
for the basal plane O spin. Both of these are in agreement with experiment but
we predict also the $g$-tensors for the other possible localization of the
spins as well as the small hyperfine splittings (as yet not observed) on Li.
The energies of formation and transition levels of the corresponding defects
provide insight into the conditions required to activate these EPR spectra.",1911.01932v2
2016-03-18,Magnons in Sr$_2$CuO$_3$: possible evidence for Goldstone-Higgs interaction in a weakly ordered spin-1/2 chain antiferromagnet,"The Goldstone theorem mandates that a spontaneous symmetry breaking entails
the emergence of gap(mass)less excitations. In the case where a rotational
invariance of a system of spin magnetic moments is broken by an
antiferromagnetic order, these are well-known transverse spin waves. The
interaction of such Goldstone magnons with the Higgs amplitude mode of the
order parameter is usually discarded, even though glimpses of Higgs physics
have recently been reported in a quantum magnet, a topological insulator, and
ferroelectric and disordered superconductor systems. The Goldstone-Higgs
interactions could be expected to grow in importance near a quantum critical
point (QCP), where the symmetry-breaking order is weak, and its amplitude
fluctuations are significant. Here we report an electron spin resonance (ESR)
study of a nearly one-dimensional spin-1/2 chain system, Sr$_2$CuO$_3$, which
presents exactly such a case. The ESR spectra at $T > T_N$, in the disordered
Luttinger-spin-liquid phase with unconfined spinons reveal ideal
Heisenberg-chain behavior with only very small, field-independent linewidth,
$\sim 1/T$. In the ordered state, below $T_N$, we identify antiferromagnetic
resonance (AFMR) modes, which are well described by pseudo-Goldstone magnons in
the model of a collinear biaxial antiferromagnet with two gaps, $\Delta_1 =
23.0$ GHz and $\Delta_2 = 13.3$ GHz. Additionally, we observe a major resonant
response of special nature, which we attribute to magnon interaction with the
Higgs amplitude mode in a weakly ordered antiferromagnet. Its unusual field
dependence indicates the presence of a quantum phase transition at $\mu_0 H
\simeq 9.4$ T.",1603.05869v2
2007-06-03,Coherent Lattice Vibrations in Superconductors,"A recent analysis by Kadin has noted that the superconducting wavefunction
within the BCS theory may be represented in real-space as a spherical
electronic orbital (on the scale of the coherence length) coupled to a
standing-wave lattice vibration. This lattice vibration, effectively a bound
phonon, has wavevector 2kf and a near-resonant frequency (on the order of the
Debye frequency) that maximizes the attractive electrostatic interaction energy
with the electronic orbital. The present paper extends this picture to a
coherent standing-wave pattern of electron and phonon waves that traverses the
entire superconductor on the macroscopic scale. These parallel planes form a
diffractive waveguide for electron waves traveling parallel to the planes,
permitting lossless supercurrent. A similar picture may be extended to
unconventional superconductors such as the cuprates, with an array of standing
spin waves rather than phonons. Such coherent lattice vibrations should be
universal and distinctive indicators of the superconducting state, and should
be observable below Tc using standard x-ray and neutron diffraction techniques.
Further implications of this picture are discussed.",0706.0338v1
2008-03-11,On an excitation mechanism for trapped inertial waves in discs around black holes,"According to one model, high-frequency quasi-periodic oscillations (QPOs) can
be identified with inertial waves, trapped in the inner regions of accretion
discs around black holes due to relativistic effects. In order to be detected,
their amplitudes need to reach large enough values via some excitation
mechanism. We work out in detail a non-linear coupling mechanism suggested by
Kato, in which a global warping or eccentricity of the disc has a fundamental
role. These large-scale deformations combine with trapped modes to generate
`intermediate' waves of negative energy that are damped as they approach either
their corotation resonance or the inner edge of the disc, resulting in
amplification of the trapped waves. We determine the growth rates of the
inertial modes, as well as their dependence on the spin of the black hole and
the properties of the disc. Our results indicate that this coupling mechanism
can provide an efficient excitation of trapped inertial waves, provided the
global deformations reach the inner part of the disc with non-negligible
amplitude.",0803.1671v1
2014-09-28,Spin-electron acoustic waves: The Landau damping and ion contribution in the spectrum,"Separated spin-up and spin-down quantum kinetics is derived for more detailed
research of the spin-electron acoustic waves. Kinetic theory allows to obtain
spectrum of the spin-electron acoustic waves including effects of occupation of
quantum states more accurately than quantum hydrodynamics. We apply quantum
kinetic to calculate the Landau damping of the spin-electron acoustic waves. We
have considered contribution of ions dynamics in the spin-electron acoustic
wave spectrum. We obtain contribution of ions in the Landau damping in
temperature regime of classic ions. Kinetic analysis for ion-acoustic, zero
sound, and Langmuir waves at separated spin-up and spin-down electron dynamics
is presented as well.",1409.7885v1
2000-06-06,The Spin Excitation Spectrum in Superconducting ${\bf YBa_2Cu_3O_{6.85}}$,"A comprehensive inelastic neutron scattering study of magnetic excitations in
the near-optimally doped high-temperature superconductor ${\rm
YBa_{2}Cu_{3}O_{6.85}}$ is presented. The spin correlations in the normal state
are commensurate with the crystal lattice, and the intensity is peaked around
the wave vector characterizing the antiferromagnetic state of the insulating
precursor ${\rm YBa_{2}Cu_{3}O_{6}}$. Profound modifications of the spin
excitation spectrum appear abruptly below the superconducting transition
temperature, $\rm T_C$, where a commensurate resonant mode and a set of weaker
incommensurate peaks develop. The data are consistent with models based on an
underlying two-dimensional Fermi surface that predict a continuous, downward
dispersion relation connecting the resonant mode and the incommensurate
excitations. The magnetic incommensurability in the ${\rm
YBa_{2}Cu_{3}O_{6+x}}$ system is thus not simply related to that of another
high temperature superconductor, ${\rm La_{2-x}Sr_xCuO_{4}}$, where
incommensurate peaks persist well above $\rm T_C$. The temperature dependent
incommensurability is difficult to reconcile with interpretations based on
charge stripe formation in ${\rm YBa_{2}Cu_{3}O_{6+x}}$ near optimum doping.",0006086v1
2001-12-11,Evolution of spin excitations in a gapped antiferromagnet from the quantum to the high-temperature limit,"We have mapped from the quantum to the classical limit the spin excitation
spectrum of the antiferromagnetic spin-1 Heisenberg chain system CsNiCl3 in its
paramagnetic phase from T=5 to 200K. Neutron scattering shows that the
excitations are resonant and dispersive up to at least T=70K, but broaden
considerably with increasing temperature. The dispersion flattens out with
increasing temperature as the resonance energy Delta at the antiferromagnetic
wave-vector increases and the maximum in the dispersion decreases. The
correlation length xi between T=12 and 50K is in agreement with quantum Monte
Carlo calculations. xi is also consistent with the single mode approximation,
suggesting that the excitations are short-lived single particle excitations.
Below T=12K where three-dimensional spin correlations are important, xi is
shorter than predicted and the experiment is not consistent with the random
phase approximation for coupled quantum chains. At T=200K, the structure factor
and second energy moment of the excitation spectrum are in excellent agreement
with the high-temperature series expansion.",0112188v1
2010-02-02,Optically tunable nuclear magnetic resonance in a single quantum dot,"We report optically detected nuclear magnetic resonance (ODNMR) measurements
on small ensembles of nuclear spins in single GaAs quantum dots. Using ODNMR we
make direct measurements of the inhomogeneous Knight field from a photo-excited
electron which acts on the nuclei in the dot. The resulting shifts of the NMR
peak can be optically controlled by varying the electron occupancy and its spin
orientation, and lead to strongly asymmetric lineshapes at high optical
excitation. The all-optical control of the NMR lineshape will enable
position-selective control of small groups of nuclear spins in a dot. Our
calculations also show that the asymmetric NMR peak lineshapes can provide
information on the volume of the electron wave-function, and may be used for
measurements of non-uniform distributions of atoms in nano-structures.",1002.0523v2
2016-10-15,Coherent spin dynamics in gadolinium-doped CaWO4 crystal,"We report the first observation of Rabi oscillations in the spin-7/2 ensemble
of trivalent gadolinium ions hosted in CaWO$_4$ single crystal. A number of
transitions within the lowest electronic multiplet $^8S_{7/2}$ of Gd$^{3+}$ ion
are studied using a combination of continuous-wave and pulsed electron
paramagnetic resonance spectroscopy. The corresponding Rabi damping curves and
the spin coherence times are detected at varying strengths of the microwave
field. These data are well reproduced by a theoretical model which accounts for
the intrinsic inhomogeneity of the microwave field within the microwave
resonator and the magnetic dipole interactions in the diluted spin ensemble.
The results indicate that the studied 8-level ground manifold of Gd$^{3+}$ ion
can represent an effective three qubit quantum system.",1610.04737v2
2016-03-28,Orbital-FFLO state in a chain of high spin ultracold atoms,"Recent experiments with Yb-173 and Sr-87 isotopes provide new possibilities
to study high spin two-orbital systems. Within these experiments part of the
atoms are excited to a higher energy metastable electronic state mimicking an
additional internal (orbital) degree of freedom. The interaction between the
atoms depends on the orbital states, therefore four different scattering
channels can be identified in the system characterized by four independent
couplings. When the system is confined into a one-dimensional chain the
scattering lengths can be tuned by changing the transverse confinement, and
driven through four resonances. Using the new available experimental data of
the scattering lengths we analyze the phase diagram of the one-dimensional
system as the couplings are tuned via transverse confinement, and the
populations of the two orbital states are changed. We found that three orders
compete showing power law decay: a state with dominant density wave
fluctuations, another one with spin density fluctuations, and a third one
characterized by exotic Fulde-Ferrell-Larkin-Ovchinnikov-like pairs consisting
one atom in the electronic ground state and one in the excited state. We also
show that sufficiently close to the resonances the compressibility of the
system starts to diverge indicating that the emerging order is unstable and
collapses to a phase separated state with a first order phase transition.",1603.08505v1
2022-08-28,Meson resonance gas in a relativistic quark model: scalar vs vector confinement and semishort range correlations,"Smooth transitions from hadronic matter to hot and dense matter of quantum
chromodynamics accompany continuous transformations in effective degrees of
freedom. The microscopic descriptions should include relativistic quarks
interacting inside of hadrons. In this work we construct a schematic
constituent quark model with relativistic kinematics which captures the global
trends of meson spectra in the light, strange, and charm quark sectors. We
examine the roles of the scalar- and vector-confining potentials as well as
semishort range correlations in estimating the strength of central, spin-spin,
and spin-orbit interactions. The quark dynamics in low-lying mesons is very
sensitive to relativistic kinematics and short range interactions, while in
high-lying mesons are sensitive to the composition of scalar- and
vector-confinement. After expressing mesons in terms of quark wave functions,
we use them to describe the quark occupation probability in a meson resonance
gas, and discuss how it can be related to its counterpart in a
quark-gluon-plasma.",2208.13312v1
2022-10-28,Resonating Valence Bond States in an Electron-Phonon System,"We study a simple electron-phonon model on square and triangular versions of
the Lieb-lattice using an asymptotically exact strong coupling analysis. At
zero temperature and electron density $n = 1$ (one electron per unit cell), for
various ranges of parameters in the model, we exploit a mapping to the quantum
dimer model to establish the existence of a spin-liquid phase with
$\mathbb{Z}_2$ topological order (on the triangular lattice) and a
multi-critical line corresponding to a quantum critical spin liquid (on the
square lattice). In the remaining part of the phase diagram, we find a host of
charge-density-wave phases (e.g. valence-bond crystals), a conventional s-wave
superconducting phase, and with the addition of a small Hubbard $U$ to tip the
balance, a phonon-induced d-wave superconducting phase. Under a special
condition, we find a hidden pseudo-spin $SU(2)$ symmetry that implies an exact
constraint on the superconducting order parameters.",2210.16321v2
2023-05-01,Theoretical analysis of multi-magnon excitations in resonant inelastic x-ray scattering spectra of two-dimensional antiferromagnets,"Resonant inelastic x-ray spectroscopy (RIXS) has emerged as an important tool
to explore magnetism in two-dimensional (2D) antiferromagnet realized in
strongly correlated materials. Here we consider the Heisenberg model with
nearest and next nearest neighbor hopping relevant to the study of magnetic
excitations of the cuprate family. We compute the RIXS cross-section within the
ultra-short core-hole lifetime (UCL) expansion of the Kramers-Heisenberg
scattering amplitude that allows perturbative solution within linear spin wave
theory (LSWT). We report detailed results for both spin-conserving and
non-conserving channels. Apart from the widely discussed single magnon and
bimagnon contributions, we show that three-magnon contributions in the spin
non-conserving channel are useful to explain certain features of the RIXS data
for two-dimensional cuprates. We confirm the qualitative correctness of the
LSWT conclusions for the three-magnon excitation with exact diagonalization.
Our work puts constraints on the dispersion of the three-magnon in the
Brillouin zone, opening new avenues for realizing higher modes of
quasiparticles using RIXS.",2305.00802v1
2003-05-31,Local Manipulation of Nuclear Spin in a Semiconductor Quantum Well,"The shaping of nuclear spin polarization profiles and the induction of
nuclear resonances are demonstrated within a parabolic quantum well using an
externally applied gate voltage. Voltage control of the electron and hole wave
functions results in nanometer-scale sheets of polarized nuclei positioned
along the growth direction of the well. RF voltages across the gates induce
resonant spin transitions of selected isotopes. This depolarizing effect
depends strongly on the separation of electrons and holes, suggesting that a
highly localized mechanism accounts for the observed behavior.",0306012v2
2008-09-04,Evolution of an Unconventional Superconducting State inside the Antiferromagnetic Phase of CeNiGe$_3$ under Pressure: a $^{73}$Ge-Nuclear-Quadrupole-Resonance Study,"We report a $^{73}$Ge nuclear-quadrupole-resonance (NQR) study on novel
evolution of unconventional superconductivity in antiferromagnetic (AFM)
CeNiGe$_3$. The measurements of the $^{73}$Ge-NQR spectrum and the nuclear
spin-lattice relaxation rate ($1/T_1$) have revealed that the unconventional
superconductivity evolves inside a commensurate AFM phase around the pressure
($P$) where N\'{e}el temperature $T_{\rm N}$ exhibits its maximum at 8.5 K. The
superconducting transition temperature $T_{\rm SC}$ has been found to be
enhanced with increasing $T_{\rm N}$, before reaching the quantum critical
point at which the AFM order collapses. Above $T_{\rm SC}$, the AFM structure
transits from an incommensurate spin-density-wave order to a commensurate AFM
order at $T\sim 2$ K, accompanied by a longitudinal spin-density fluctuation.
With regard to heavy-fermion compounds, these novel phenomena have hitherto
never been reported in the $P$-$T$ phase diagram.",0809.0770v1
2009-08-01,Study of Electron Spin Resonance on single crystals $EuFe_{2-x}Co_{x}As_2$,"The temperature dependence of electron spin resonance (ESR) was studied in
$EuFe_{2-x}Co_{x}As_2 $ (x = 0.0, 0.067, 0.1, 0.2, 0.25, 0.285, 0.35, 0.4 and
0.5). The ESR spectrum of all the samples indicates that the g factor and
peak-to-peak linewidth strongly depend on the temperature. Moreover, the
peak-to-peak linewidth shows the Korringa behavior, indicating an exchange
coupling between the conduction electrons and the $Eu^{2+}$ions. The linewidth,
g factor and the integrate ESR intensity show anomalies at the temperature of
the spin-density-wave (SDW). The linewidth below the SDW transition does not
rely on the temperature. This gives the evidence of the gap opening at the
$T_{SDW}$. The slope of the linewidth is closely associated to $T_{SDW}$and
$T_C$. This exotic behavior may be related to the nesting of the Fermi surface.",0908.0037v1
2012-02-20,Spin Exciton Formation inside the Hidden Order Phase of CeB6,"The heavy fermion metal CeB6 exhibits hidden order of antiferroquadrupolar
(AFQ) type below T_Q=3.2K and subsequent antiferromagnetic (AFM) order at
T_N=2.3K. It was interpreted as ordering of the quadrupole and dipole moments
of a $\Gamma_8$ quartet of localised Ce $4f^1$ electrons. This established
picture has been profoundly shaken by recent inelastic neutron scattering (G.
Friemel et al., arXiv:1111.4151) that found the evolution of a feedback spin
exciton resonance within the hidden order phase at the AFQ wave vector which is
stabilized by the AFM order. We develop an alternative theory based on a
fourfold degenerate Anderson lattice model, including both order parameters as
particle-hole condensates of itinerant heavy quasiparticles. This explains in a
natural way the appearance of the spin exciton resonance and the momentum
dependence of its spectral weight, in particular around the AFQ vector and its
rapid disappearance in the disordered phase. Analogies to the feedback effect
in unconventional heavy fermion superconductors are pointed out.",1202.4291v1
2012-05-17,Gapped spin liquid phase in the J1-J2 Heisenberg model by a Bosonic resonating valence-bond ansatz,"We study the ground-state phase diagram of the spin-1/2 J1-J2 Heisenberg
model on the square lattice with an accurate Bosonic resonating valence-bond
(RVB) wave function. In contrast to the RVB ansatz based on Schwinger Fermions,
the representation based on Schwinger Bosons, supplemented by a variational
Monte Carlo technique enforcing the exact projection onto the physical
subspace, is able to describe a fully gapped spin liquid in the strongly
frustrated regime. In particular, a fully symmetric Z2 spin liquid is stable
between two antiferromagnetic phases; a continuous transition at J2=0.4J1, when
the Marshall sign rule begins to be essentially violated, and a first-order
transition around J2=0.6J1 are present. Most importantly, the triplet gap is
found to have a non-monotonic behavior, reaching a maximum around J2=0.51J1,
when the lowest spinon excitation moves from the \Gamma to the M point, i.e.,
k=(\pi,0).",1205.3838v1
2018-08-14,Dynamical multistability in a quantum-dot laser,"We study the dynamical multistability of a solid-state single-atom laser
implemented in a quantum-dot spin valve. The system is formed by a resonator
that interacts with a two-level system in a dot in contact with two
ferromagnetic leads of antiparallel polarization. We show that a spin-polarized
current provides high-efficiency pumping leading to regimes of multistable
lasing, in which the Fock distribution of the oscillator displays a
multi-peaked distribution. The emergence of multistable lasing follows from the
breakdown of the usual rotating-wave approximation for the coherent
spin-resonator interaction which occurs at relatively weak couplings. The
multistability manifests itself directly in the charge current flowing through
the dot, switching between distinct current levels corresponding to the
different states of oscillation.",1808.04884v2
2019-02-20,Photoinduced Floquet topological magnons in Kitaev magnets,"We study periodically driven pure Kitaev model and ferromagnetic phase of the
Kitaev-Heisenberg model on the honeycomb lattice by off-resonant linearly and
circularly-polarized lights at zero magnetic field. Using a combination of
linear spin wave and Floquet theories, we show that the effective
time-independent Hamiltonians in the off-resonant regime map onto the
corresponding anisotropic static spin model, plus a tunable photoinduced
magnetic field along the $[111]$ direction, which precipitates Floquet
topological magnons and chiral magnon edge modes. They are tunable by the light
amplitude and polarization. Similarly, we show that the thermal Hall effect
induced by the Berry curvature of the Floquet topological magnons can also be
tuned by the laser field. Our results pave the way for ultrafast manipulation
of topological magnons in irradiated Kitaev magnets, and could play a pivotal
role in the investigation of ultrafast magnon spin current generation in Kitaev
materials.",1902.07716v2
2019-12-30,Hybrid nanophotonic-nanomagnonic SiC-YiG quantum sensor: II/ optical fiber based ODMR and OP-PELDOR experiments on bulk HPSI 4H-SiC,"Here I present my first fiber based coupled optical and EPR experiments
associated to the development of a new SiC-YiG quantum sensor that I recently
theoretically described (arXiv:1912.11634). This quantum sensor was designed to
allow sub-nanoscale single external spin sensitivity optically detected pulsed
electron electron double resonance spectroscopy, using an X band pulsed EPR
spectrometer, an optical fiber, and a photoluminescence setup. First key
experiments before the demonstration of ODPELDOR spectroscopy are presented
here. They were performed on a bulk 4H-SiC sample containing an ensemble of
residual V2 color centers (spin S=3/2). Here I demonstrate i/ optical pumping
assisted pulsed EPR experiments, ii/ fiber based ODMR and optically detected
RABI oscillations, and iii/ optical pumping assisted PELDOR experiments, and
iv/ some spin wave resonance experiments. Those experiments confirm the
feasability of the new quantum sensing approach proposed.",1912.13111v1
2009-11-12,Spin Resonance and dc Current Generation in a Quantum Wire,"We show that in a quantum wire the spin-orbit interaction leads to a narrow
spin resonance at low temperatures, even in the absence of an external magnetic
field. Resonance absorption by linearly polarized radiation gives a dc spin
current; resonance absorption by circularly polarized radiation gives a dc
electric current or magnetization.",0911.2433v1
2021-01-22,Spin dynamics in NaFeAs and NaFe$_{0.53}$Cu$_{0.47}$As probed by resonant inelastic X-ray scattering,"The parent compounds of iron-based superconductors are magnetically-ordered
bad metals, with superconductivity appearing near a putative magnetic quantum
critical point. The presence of both Hubbard repulsion and Hund's coupling
leads to rich physics in these multiorbital systems, and motivated descriptions
of magnetism in terms of itinerant electrons or localized spins. The
NaFe$_{1-x}$Cu$_x$As series consists of magnetically-ordered bad metal ($x=0$),
superconducting ($x\approx0.02$) and magnetically-ordered
semiconducing/insulating ($x\approx0.5$) phases, providing a platform to
investigate the connection between superconductivity, magnetism and electronic
correlations. Here we use X-ray absorption spectroscopy and resonant inelastic
X-ray scattering to study the valence state of Fe and spin dynamics in two
NaFe$_{1-x}$Cu$_x$As compounds ($x=0$ and 0.47). We find that magnetism in both
compounds arises from Fe$^{2+}$ atoms, and exhibits underdamped dispersive spin
waves in their respective ordered states. The dispersion of spin excitations in
NaFe$_{0.53}$Cu$_{0.47}$As is consistent with being quasi-one-dimensional.
Compared to NaFeAs, the band top of spin waves in NaFe$_{0.53}$Cu$_{0.47}$As is
slightly softened with significantly more spectral weight of the spin
excitations. Our results indicate the spin dynamics in
NaFe$_{0.53}$Cu$_{0.47}$As arise from localized magnetic moments and suggest
the iron-based superconductors are proximate to a correlated insulating state
with localized iron moments.",2101.08948v1
2000-03-18,"New Resonant Bivacuum Mediated Interaction, as a Possible Explanation of Psi Phenomena","This paper contains development of following theories and models, related to
Psi phenomena, based on our Unified concept of Bivacuum, particles duality,
fields and time: - Theory of Virtual Replica (VR) of material objects in
Bivacuum and VR Multiplication: VRM (r,t). The VR represents a
three-dimensional (3D) superposition of Bivacuum virtual pressure waves VPW and
spin waves VirSW, modulated by pulsation of elementary particles and
translational and librational de Broglie waves of molecules of macroscopic
object (http://arxiv.org/abs/physics/0207027). The infinitive multiplication of
primary VR in space in form of 3D packets of virtual standing waves: VRM(r), is
a result of interference of all pervading external coherent basic reference
waves: (VPW) and (VirSW) with similar kinds of waves, forming VR. This
phenomena may stands for remote vision; - Theory of nonlocal Virtual Guides
(VirG) of spin, momentum and energy, with properties of quasi one-dimensional
virtual Bose condensate of bivacuum dipoles. The bundles of VirG, connecting
coherent atoms of Sender (S) and Receiver (S), are responsible for nonlocal
weak interaction; - Theory of Bivacuum Mediated Interaction (BMI) responsible
for nonlocal interaction and different Psi-phenomena without contradictions
with fundamental laws of Nature.",0003044v3
2017-01-03,Faraday waves by resonant triad interaction of surface--compression waves,"The propagation of wave disturbances over a vertically oscillating liquid may
form standing waves, known as Faraday waves. Here we present an alternative
description of the generation and evolution of Faraday waves by nonlinear
resonant triad interactions, accounting for gravity surface effects and the
slight compressibility of the liquid. To this end, we analyse a triad
comprising an infinitely long-crested compression mode and two oppositely
propagating subharmonic surface waves.",1701.00667v1
2006-11-02,Electron Fabry-Perot interferometer with two entangled magnetic impurities,"We consider a one-dimensional (1D) wire along which single conduction
electrons can propagate in the presence of two spin-1/2 magnetic impurities.
The electron may be scattered by each impurity via a contact-exchange
interaction and thus a spin-flip generally occurs at each scattering event.
Adopting a quantum waveguide theory approach, we derive the stationary states
of the system at all orders in the electron-impurity exchange coupling
constant. This allows us to investigate electron transmission for arbitrary
initial states of the two impurity spins. We show that for suitable electron
wave vectors, the triplet and singlet maximally entangled spin states of the
impurities can respectively largely inhibit the electron transport or make the
wire completely transparent for any electron spin state. In the latter case, a
resonance condition can always be found, representing an anomalous behaviour
compared to typical decoherence induced by magnetic impurities. We provide an
explanation for these phenomena in terms of the Hamiltonian symmetries.
Finally, a scheme to generate maximally entangled spin states of the two
impurities via electron scattering is proposed.",0611025v2
2012-03-29,Correlation functions in SU(2)-invariant RVB spin liquids on nonbipartite lattices,"We introduce a Monte Carlo scheme based on sampling of Pfaffians to
investigate Anderson's resonating-valence-bond (RVB) spin liquid wave function
on the kagome and the triangular lattice. This eliminates a sign problem that
prevents utilization of the valence bond basis in Monte Carlo studies for
non-bipartite lattices. Studying lattice sizes of up to 600 sites, we calculate
singlet-singlet and spin-spin correlations, and demonstrate how the lattice
symmetry is restored within each topological sector as the system size is
increased. Our findings are consistent with the expectation that the nearest
neighbor RVB states describe a topological spin liquid on these non-bipartite
lattices.",1203.6621v2
2013-10-31,Two distinct spin liquid states in a layered cubic lattice,"We construct a family of short-range resonating-valence-bond wave functions
on a layered cubic lattice, allowing for a tunable anisotropy in the amplitudes
assigned to nearest-neighbour valence bonds along one axis. Monte Carlo
simulations reveal that four phases are stabilized over the full range of the
anisotropy parameter. They are separated from one another by a sequence of
continuous quantum phase transitions. An antiferromagnetic phase, centred on
the perfect isotropy point, intervenes between two distinct quantum spin liquid
states. One of them is continuously deformable to the two-dimensional U(1) spin
liquid, which is known to exhibit critical bond correlations. The other has
both spin and bond correlations that decay exponentially. The existence of this
second phase is proof that, contrary to expectations, neither a bipartite
lattice structure nor a conventional Marshall sign rule is an impediment to
realizing a fully gapped quantum spin liquid.",1311.0004v1
2016-08-19,Competing Exchange Interactions in the Multiferroic and Ferrimagnetic CaBaCo$_4$O$_7$,"Competing exchange interactions can produce complex magnetic states together
with spin-induced electric polarizations. With competing interactions on
alternating triangular and kagome layers, the swedenborgite CBO may have one of
the largest measured spin-induced polarizations of about 1700 nC/cm$^2$ below
its ferrimagnetic transition temperature at 70 K. Powder neutron-diffraction
data, magnetization measurements, and spin-wave resonance frequencies in the
THz range reveal that the complex spin order of multiferroic CBO can be
described as a triangular array of c-axis chains ferrimagnetically coupled to
each other in the ab plane. Magnetostriction on bonds that couple those chains
produces the large spin-induced polarization of CBO.",1608.05628v3
2017-06-19,Chiral Spin Mode on the Surface of a Topological Insulator,"Using polarization-resolved resonant Raman spectroscopy, we explore
collective spin excitations of the chiral surface states in a three dimensional
topological insulator, Bi$_2$Se$_3$. We observe a sharp peak at 150 meV in the
pseudovector $A_2$ symmetry channel of the Raman spectra. By comparing the data
with calculations, we identify this peak as the transverse collective spin mode
of surface Dirac fermions. This mode, unlike a Dirac plasmon or a surface
plasmon in the charge sector of excitations, is analogous to a spin wave in a
partially polarized Fermi liquid, with spin-orbit coupling playing the role of
an effective magnetic field.",1706.05776v3
2021-04-19,Unconventional quantum sound-matter interactions in spin-optomechanical-crystal hybrid systems,"We predict a set of unusual quantum acoustic phenomena resulting from
sound-matter interactions in a fully tunable solid-state platform, in which an
array of solid-state spins in diamond are coupled to quantized acoustic waves
in a one-dimensional (1D) optomechanical crystal. We find that, by a spatially
varying laser drive that introduces a position-dependent phase in the
optomechanical interaction, the mechanical band structure can be tuned in situ,
consequently leading to unconventional quantum sound-matter interactions. We
show that quasi-chiral sound-matter interactions can occur, with tunable ranges
from bidirectional to quasi-unidirectional, when the spins are resonant with
the bands. When the solid-state spins'frequency lies within the acoustic
band-gap, we demonstrate the emergence of an exotic polariton bound state,
which can mediate long-range tunable, odd-neighbor and complex spin-spin
interactions. This work expands the present exploration of quantum phononics
and can have wide applications in quantum simulation and quantum information
processing.",2104.09101v1
2020-02-27,Electric control of spin orbit coupling in graphene-based nanostructures with broken rotational symmetry,"Spin and angular momenta of light are important degrees of freedom in
nanophotonics which control light propagation, optical forces and information
encoding. Typically, optical angular momentum is generated using q-plates or
spatial light modulators. Here, we show that graphene-supported plasmonic
nanostructures with broken rotational symmetry provide a surprising spin to
orbital angular momentum conversion, which can be continuously controlled by
changing the electrochemical potential of graphene. Upon resonant illumination
by a circularly polarized plane wave, a polygonal array of indium-tin-oxide
nanoparticles on a graphene sheet generates scattered field carrying
electrically-tunable orbital angular momentum. This unique photonic spin-orbit
coupling occurs due to the strong coupling of graphene plasmon polaritons and
localised surface plasmons of the nanoparticles and leads to the controlled
directional excitation of graphene plasmons. The tuneable spin-orbit conversion
pave the way to high-rate information encoding in optical communications,
electric steering functionalities in optical tweezers, and nanorouting of
higher-dimensional entangled photon states.",2002.12058v1
2021-09-28,Spin oscillations of a single-mode polariton system driven by a plane wave,"Theoretical study is performed of a single-mode polariton system with linear
coupling of spin components. When combined with an ordinary two-particle
interaction, the spin coupling involves a spontaneous symmetry breaking
accompanied by a switch from linear to circular polarization under resonant
driving. The asymmetric steady states can also lose stability, giving way to
oscillatory and chaotic dynamics. Here, we explore a continuous transformation
between the multistable regime, where the system is steady and locked in phase
to the pump but has a broken spin symmetry, and full-span oscillations of the
circular-polarization degree, owing to which the symmetry is effectively
reestablished. Such oscillations are analogous to the intrinsic Josephson
effect and prove to be robust against arbitrarily strong perturbations.
Transitional phenomena include the Hopf bifurcation, spin bistability of limit
cycles, and continuous transitions to and from dynamical chaos through series
of period doubling/halving events.",2109.13775v3
2024-04-17,Self-Ordered Supersolid in Spinor Condensates with Cavity-Mediated Spin-Momentum-Mixing Interactions,"Ultracold atoms with cavity-mediated long-range interactions offer a
promising platform for investing novel quantum phenomena. Exploiting recent
experimental advancements, we propose an experimental scheme to create
self-ordered supersolid in spin-$1/2$ condensates confined within an optical
cavity. The interplay of cavity and pump fields gives rise to supersolid square
and plane wave phases, comprehensively described by the two-component
Tavis-Cummings model. We show that the self-ordered supersolid phase exhibits
an undamped gapless Goldstone mode over a wide parameter range. This proposal,
achievable with current experimental setups utilizing identical laser
configurations, is in contrast to the realization of checkerboard
supersolidity, which hinges on constructing a $U(1)$ symmetry by utilizing two
${\cal Z}_2$ symmetries with precisely matched atom-cavity coupling in
multimode resonators. By employing the superradiant photon-exchange process, we
realize for the first time cavity-mediated spin-momentum-mixing interactions
between highly correlated spin and momentum modes, analogous to that observed
spin-mixing in spin-1 condensates. Our scheme provides a unique platform for
realizing spin-momentum squeezing and spatially distributed multipartite
entanglement.",2404.11157v1
2000-03-23,XPS and NMR as Complementary Probes of Pseudogaps and Spin-charge Separation,"The possibility that strongly correlated many-electron systems may exhibit
spin-charge separation has generated great excitement, particularly in the
light of recent experiments on low dimensional conductors and high temperature
superconductors. However, finding experimental support for this hypothesis has
been made difficult by the fact that most commonly used probes couple
simultaneously to spin and charge excitations. We argue that core hole
photoemission (XPS)/nuclear magnetic resonance (NMR) couple independently and
in exactly comparable ways to the local charge/spin susceptibilities of the
system being measured. The explicit comparison of XPS and NMR data,
particularly in systems which exhibit a pseudogap, may therefore yield fresh
evidence for the existence (or non-existence) of spin-charge separation.
Application of these ideas to the normal state of high temperature
superconductors is discussed, and the application is further illustrated in
some detail for quasi one-dimensional systems with charge density waves.",0003385v2
2002-12-12,Spin Precession and Oscillations in Mesoscopic Systems,"We compare and contrast magneto-transport oscillations in the fully quantum
(single-electron coherent) and classical limits for a simple but illustrative
model. In particular, we study the induced magnetization and spin current in a
two-terminal double-barrier structure with an applied Zeeman field between the
barriers and spin disequilibrium in the contacts. Classically, the spin current
shows strong tunneling resonances due to spin precession in the region between
the two barriers. However, these oscillations are distinguishable from those in
the fully coherent case, for which a proper treatment of the electron phase is
required. We explain the differences in terms of the presence or absence of
coherent multiple wave reflections.",0212308v1
2005-04-14,Optical pumping of the electron spin polarization in bulk CuCl,"In CuCl bulk crystal negatively charged excitons (trions $X^-$) can be
induced by the resonant optical excitation of extra electrons in conduction
band minimum. In the case of light polarization and due to the top valence band
structure of CuCl only the electrons with spin antiparallel to the direction of
the light propagation contribute to the formation of $X^-$, while the emerging
$X^-$ can recombine into both possible electron states, with spin parallel and
antiparallel to the direction of light propagation. We propose to use this
mechanism for optical electronic spin pumping. We describe the dynamics of
pumping in terms of density matrix formalism. The coherent pumping laser pulse
propagating through the sample is described by Maxwell wave equation coupled to
the density matrix evolution equations. The results of our approximate simple
model calculations suggest that spin polarization close to 100% can be achieved
in time shorter than 100ps.",0504368v2
2015-02-18,Spectral shape deformation in inverse spin Hall voltage in Y3Fe5O12|Pt bilayers at high microwave power levels,"We report on the deformation of microwave absorption spectra and of the
inverse spin Hall voltage signals in thin film bilayers of yttrium iron garnet
(YIG) and platinum at high microwave power levels in a 9.45-GHz TE011 cavity.
As the microwave power increases from 0.15 to 200 mW, the resonance field
shifts to higher values, and the initially Lorentzian spectra of the microwave
absorption intensity as well as the inverse spin Hall voltage signals become
asymmetric. The contributions from opening of the magnetization precession cone
and heating of YIG cannot well reproduce the data. Control measurements of
inverse spin Hall voltages on thin-film YIG|Pt systems with a range of line
widths underscore the role of spin-wave excitations in spectral deformation.",1502.05198v1
2015-09-15,Dynamical current-induced ferromagnetic and antiferromagnetic resonances,"We demonstrate that ferromagnetic and antiferromagnetic excitations can be
triggered by the dynamical spin accumulations induced by the bulk and surface
contributions of the spin Hall effect. Due to the spin-orbit interaction, a
time-dependent spin density is generated by an oscillatory electric field
applied parallel to the atomic planes of Fe/W(110) multilayers. For symmetric
trilayers of Fe/W/Fe in which the Fe layers are ferromagnetically coupled, we
demonstrate that only the collective out-of-phase precession mode is excited,
while the uniform (in-phase) mode remains silent. When they are
antiferromagnetically coupled, the oscillatory electric field sets the Fe
magnetizations into elliptical precession motions with opposite angular
velocities. The manipulation of different collective spin-wave dynamical modes
through the engineering of the multilayers and their thicknesses may be used to
develop ultrafast spintronics devices. Our work provides a general framework
that probes the realistic responses of materials in the time or frequency
domain.",1509.04599v2
2018-03-06,Methods for preparation and detection of neutron spin-orbit states,"The generation and control of neutron orbital angular momentum (OAM) states
and spin correlated OAM (spin-orbit) states provides a powerful probe of
materials with unique penetrating abilities and magnetic sensitivity. We
describe techniques to prepare and characterize neutron spin-orbit states, and
provide a quantitative comparison to known procedures. The proposed detection
method directly measures the correlations of spin state and transverse
momentum, and overcomes the major challenges associated with neutrons, which
are low flux and small spatial coherence length. Our preparation techniques,
utilizing special geometries of magnetic fields, are based on coherent
averaging and spatial control methods borrowed from nuclear magnetic resonance.
The described procedures may be extended to other probes such as electrons and
electromagnetic waves.",1803.02295v1
2018-09-07,Quantum interferometry with a g-factor-tunable spin qubit,"We study quantum interference effects of a qubit whose energy levels are
continuously modulated. The qubit is formed by an impurity electron spin in a
silicon tunneling field-effect transistor, and it is read out by spin blockade
in a double-dot configuration. The qubit energy levels are modulated via its
gate-voltage-dependent g-factors, with either rectangular, sinusoidal, or ramp
radio-frequency waves. The energy-modulated qubit is probed by the electron
spin resonance. Our results demonstrate the potential of spin qubit
interferometry implemented in a silicon device and operated at a relatively
high temperature.",1809.02326v2
2021-01-18,Observation of Majorana Plasmon by Molecular Topological Superconductor and Its Topological SPASER,"Plasmons, quantized collective oscillations of electrons, have been observed
in metals and semiconductors. Such massive electrons have been the basic
ingredients of research in plasmonics and optical metamaterials.1 Also, Dirac
plasmons have been observed in graphene, two-dimensional electron systems and
topological insulators (TIs). A nontrivial Z2 topology of the bulk valence band
leads to the emergence of massless Dirac fermions on the surface in TIs.2,3
Although Dirac plasmons can be formed through additional grating or patterning,
their characteristics promise novel plasmonic metamaterials that are tunable in
the terahertz and mid-infrared frequency ranges.4 Recently, the Majorana
fermions have been verified through various kinds of topological
superconductors(TSCs). In particular, the quantized and paired spin waves have
been discovered in polyaromatic hydrocarbons(PAHs)5 and Majorana hinge and
corner modes have been identified in the organic crystal of PAHs.
Interestingly, regularity and periodicity can serve in the xy-plane of the
crystal as the patterning of TSC resonators. Here, first we report experimental
evidence of Majorana plasmonic excitations in a molecular topological
superconductor (MTSC). It was prepared from MTSC resonators with different
stacked numbers of HYLION-12. Distributing carriers into multiple MTSC
resonators enhance the plasmonic resonance frequency and magnitude, which is
different from the effects in a conventional semiconductor superlattice.6,7 The
direct results of the unique carrier density scaling law of the resonance of
massless Majorana fermions is demonstrated. Moreover, topological surface
plasmon amplification by stimulated emission of radiation (SPASER) is also
firstly created from the MTSC resonator. It has two mutually time-reversed
chiral surface plasmon modes carrying the opposite topological charges.",2101.06882v1
2009-04-30,Terahertz time-domain spectroscopy of electromagnons in multiferroic perovskite manganites,"Recent spectroscopic studies at terahertz frequencies for a variety of
multiferroics endowed with both ferroelectric and magnetic orders have revealed
the possible emergence of a new collective excitation, frequently referred to
as electromagnon. It is magnetic origin, but becomes active in response to the
electric field component of light. Here we give an overview on our recent
advance in the terahertz time-domain spectroscopy of electromagnons or
electric-dipole active magnetic resonances, focused on perovskite
manganites--$R$MnO$_3$ ($R$ denotes rare-earth ions). The respective electric
and magnetic contributions to the observed magnetic resonance are firmly
identified by the measurements of the light-polarization dependence using a
complete set of the crystal orientations. We extract general optical features
in a variety of the spin ordered phases, including the $A$-type
antiferromagnetic, collinear spin ordered, and ferroelectric $bc$ and $ab$
spiral spin ordered phases, which are realized by tuning the chemical
composition of $R$, temperature, and external magnetic field. In addition to
the antiferromagnetic resonances of Mn ions driven by the magnetic field
component of light, we clarify that the electromagnon appears only for light
polarized along the a-axis even in the collinear spin ordered phase and grows
in intensity with evolution of the spiral spin order, but independent of the
direction of the spiral spin plane ($bc$ or $ab$) or equivalently the direction
of the ferroelectric polarization $P_{\rm s}$ ($P_{\rm s}\| c$ or $P_{\rm s}\|
a$). A possible origin of the observed magnetic resonances at terahertz
frequencies is discussed by comparing the systematic experimental data
presented here with theoretical considerations based on Heisenberg model.",0904.4796v1
2018-10-29,"On the resonant reflection of weak, nonlinear sound waves off an entropy wave","We derive a degenerate quasilinear Schr\""odinger equation that describes the
resonant reflection of very weak, nonlinear sound waves off a weak sawtooth
entropy wave.",1810.11913v1
2023-06-09,Static and dynamical properties of the spin-5/2 nearly ideal triangular lattice antiferromagnet Ba3MnSb2O9,"We study the ground state and spin excitations in Ba3MnSb2O9, an easy-plane S
= 5/2 triangular lattice antiferromagnet. By combining single-crystal neutron
scattering, electric spin resonance (ESR), and spin wave calculations, we
determine the frustrated quasi-two-dimensional spin Hamiltonian parameters
describing the material. While the material has a slight monoclinic structural
distortion, which could allow for isosceles-triangular exchanges and biaxial
anisotropy by symmetry, we observe no deviation from the behavior expected for
spin waves in the in-plane 120o state. Even the easy-plane anisotropy is so
small that it can only be detected by ESR in our study. In conjunction with the
quasi-two-dimensionality, our study establishes that Ba3MnSb2O9 is a nearly
ideal triangular lattice antiferromagnet with the quasi-classical spin S = 5/2,
which suggests that it has the potential for an experimental study of Z- or
Z2-vortex excitations.",2306.05802v2
2021-09-30,Spin waves in doped graphene: a time-dependent spin-density-functional approach to collective excitations in paramagnetic two-dimensional Dirac fermion gases,"In spin-polarized itinerant electron systems, collective spin-wave modes
arise from dynamical exchange and correlation (xc) effects. We here consider
spin waves in doped paramagnetic graphene with adjustable Zeeman-type band
splitting. The spin waves are described using time-dependent
spin-density-functional response theory, treating dynamical xc effects within
the Slater and Singwi-Tosi-Land-Sjolander approximations. We obtain spin-wave
dispersions and spin stiffnesses as a function of doping and spin polarization,
and discuss prospects for their experimental observation.",2110.00045v1
2002-07-03,Temperature dependence and mechanism of electrically detected ESR at the n=1 filling factor of a two-dimensional electron system in GaAs quantum wells,"Electrically detected electron spin resonance (EDESR) signals were acquired
as a function of temperature in the 0.3-4.2 K temperature range in a
AlGaAs/GaAs multiple quantum well sample at the filling factor at 5.7 T. In the
particular sample studied, the line width is approximately temperature
independent, while the amplitude exhibits a maximum at about 2.2 K and vanishes
with increased or decreased temperature. To explain the observed temperature
dependence of the signal amplitude, the signal amplitude temperature dependence
is calculated assuming a model based on heating. The model ascribes the
resonant absorption of microwave power of the 2DES to the uniform mode of the
electron spin magnetization where the elementary spin excitations at filling
factor are taken to be spin waves, while the short wavelength spin wave modes
serve as a heat sink for the absorbed energy. Due to the finite thermal
conductance to the surroundings, the temperature of the 2DES spin wave system
is increased, resulting in a thermal activation of the longitudinal
magnetoconductance. The proposed heating model correctly predicts the location
of the maximum in the experimentally observed temperature dependence of the
EDESR amplitude. It also correctly predicts that the signal should vanish as
the temperature is increased or decreased. The results of the present study
demonstrate how experimental EDESR studies can, under appropriate conditions,
provide data that can be used to discriminate between competing theories for
the magnetic ordering and magnetic excitations of a 2DES in the regime of the
quantum Hall effect.",0207108v1
2012-11-06,Tidal resonance locks in inspiraling white dwarf binaries,"We calculate the tidal response of helium and carbon/oxygen (C/O) white dwarf
(WD) binaries inspiraling due to gravitational wave emission. We show that
resonance locks, previously considered in binaries with an early-type star,
occur universally in WD binaries. In a resonance lock, the orbital and spin
frequencies evolve in lockstep, so that the tidal forcing frequency is
approximately constant and a particular normal mode remains resonant, producing
efficient tidal dissipation and nearly synchronous rotation. We show that
analogous locks between the spin and orbital frequencies can occur not only
with global standing modes, but even when damping is so efficient that the
resonant tidal response becomes a traveling wave. We derive simple analytic
formulas for the tidal quality factor Q and tidal heating rate during a g-mode
resonance lock, and verify our results numerically. We find that Q ~ 10^7 for
orbital periods ~ 1 - 2 hr in C/O WDs, and Q ~ 10^9 for P_orb ~ 3 - 10 hr in
helium WDs. Typically tidal heating occurs sufficiently close to the surface
that the energy should be observable as surface emission. Moreover, near an
orbital period of ~ 10 min, the tidal heating rate reaches ~ 10^{-2} L_\sun,
rivaling the luminosities of our fiducial WD models. Recent observations of the
13-minute double-WD binary J0651 are roughly consistent with our theoretical
predictions. Tides naturally tend to generate differential rotation; however,
we show that the fossil magnetic field strength of a typical WD can maintain
solid-body rotation down to at least P_orb ~ 10 min even in the presence of a
tidal torque concentrated near the WD surface.",1211.1393v4
1994-06-17,An Upper Bound for the Spin-Wave Spectrum of the Heisenberg Antiferromagnet,"We study the spin-wave spectrum of the Heisenberg antiferromagnet on a
bipartite lattice. The spin-wave spectrum on a N\'eel-ordered ground state is
bounded as $\varepsilon (k) \le c |k| $, where $c$ gives an upper bound for the
spin-wave velocity. In the large-$S$ limit, the upper bound $c$ coincides with
the result of the spin-wave theory.",9406077v1
2015-12-18,Domain Walls as Spin Wave Waveguides,"We numerically demonstrate that domain walls can be used as spin wave
waveguides. We show that gapless spin waves bounded inside a domain wall can be
guided by the domain wall. For Bloch walls, we further show that the bound spin
waves can pass through Bloch lines and corners without reflection. This finding
makes domain-wall-based spin wave devices possible.",1512.05965v2
2000-08-30,Direct-decay properties of charge-exchange spin giant resonances,"An extended continuum-RPA approach is applied to describe direct-decay
properties of spin giant resonances in $^{208}$Bi and $^{90}$Nb. Partial
branching ratios for direct proton decay from these resonances are evaluated.
The branching ratio for $\gamma$-decay from the spin-dipole resonance to the
Gamow-Teller resonance (main peak) is estimated. The saturation-like behaviour
of the mean doorway-state spreading width in $^{208}$Pb is discussed in
connection with the branching ratio for direct proton decay from the
spin-monopole resonance and the Gamow-Teller strength distribution.",0008062v1
2022-01-03,Handedness-filter and Doppler shift of spin waves in ferrimagnetic domain walls,"Excitation and propagation of spin waves inside magnetic domain walls has
received attention because of their potentials in spintronic and communication
applications. Besides wave amplitude and frequency, spin-wave has its third
character: handedness, whose manipulation is certainly of interest. We propose
in this Letter that the handedness of low energy spin-wave excitations can be
controlled by tuning the net angular momentum {\delta}s in a ferrimagnetic
(FiM) domain wall, attributing to the inequivalent magnetic sublattices. The
results indicate that the spin-wave dispersion depends on both {\delta}s and
wave handedness. For a positive (negative) {\delta}s, a gapless dispersion is
observed for the left-handed (righ-handed) spin waves, while a frequency gap
appears for the right-handed (left-handed) spin waves. Thus a FiM wall could
serve as a multifold filter of low energy spin-wave in which only spin waves
with particular handedness can propagate. Furthermore, the energy consumption
loss for spin-wave excitation in the wall is much lower than that inside the
domain, while the group velocity is much faster too, demonstrating the
advantages of domain walls serving as spin waveguides. Moreover, the
current-induced spin-wave Doppler shift in the FiM wall is also revealed, and
can be controlled by {\delta}s. This work unveils for the first time the
interesting spin-wave dynamics in FiM domain walls, benefiting future spin-wave
applications.",2201.00623v2
2001-01-07,Formation and Dynamics of a Schrödinger-Cat State in Continuous Quantum Measurement,"We consider the process of a single-spin measurement using magnetic resonance
force microscopy (MRFM) as an example of a truly continuous measurement in
quantum mechanics. This technique is also important for different applications,
including a measurement of a qubit state in quantum computation. The
measurement takes place through the interaction of a single spin with a
quasi-classical cantilever, modeled by a quantum oscillator in a coherent state
in a quasi-classical region of parameters. The entire system is treated
rigorously within the framework of the Schr\""odinger equation, without any
artificial assumptions. Computer simulations of the spin-cantilever dynamics,
where the spin is continuously rotated by means of cyclic adiabatic inversion,
show that the cantilever evolves into a Schr\""odinger-cat state: the
probability distribution for the cantilever position develops two asymmetric
peaks that quasi-periodically appear and vanish. For a many-spin system our
equations reduce to the classical equations of motion, and we accurately
describe conventional MRFM experiments involving cyclic adiabatic inversion of
the spin system. We surmise that the interaction of the cantilever with the
environment would lead to a collapse of the wave function; however, we show
that in such a case the spin does not jump into a spin eigenstate.",0101035v1
2023-09-11,Quantum control and Berry phase of electron spins in rotating levitated diamonds in high vacuum,"Levitated diamond particles in high vacuum with internal spin qubits have
been proposed for exploring macroscopic quantum mechanics, quantum gravity, and
precision measurements. The coupling between spins and particle rotation can be
utilized to study quantum geometric phase, create gyroscopes and rotational
matter-wave interferometers. However, previous efforts in levitated diamonds
struggled with vacuum level or spin state readouts. To address these gaps, we
fabricate an integrated surface ion trap with multiple stabilization
electrodes. This facilitates on-chip levitation and, for the first time,
optically detected magnetic resonance measurements of a nanodiamond levitated
in high vacuum. The internal temperature of our levitated nanodiamond remains
moderate below $10^{-5}$ Torr. Impressively, we have driven a nanodiamond to
rotate up to 20 MHz ($1.2 \times 10^{9}$ rpm), surpassing typical
nitrogen-vacancy (NV) center electron spin dephasing rates. Using these NV
spins, we observe the effect of the Berry phase arising from particle rotation.
In addition, we demonstrate quantum control of spins in a rotating nanodiamond.
These results mark an important development in interfacing mechanical rotation
with spin qubits, expanding our capacity to study quantum phenomena.",2309.05821v2
2023-02-02,Spin waves in a ferromagnetic topological metal,"In most metals, charges and spins can hop rapidly between atoms, yielding
strong dispersion of their energy versus momentum. There are, however, special
arrangements of atoms, such as twisted graphene bilayers or lattices which
resemble woven bamboo ""kagome"" mats, so that particle motion with strong
hopping between neighbours becomes nearly or even completely dispersionless.
Such flat bands are interesting because the interactions between the heavy
particles inhabiting them will become much more important than for strong
dispersion, resulting in novel quantum solid and liquid states, particularly
when topology enters on account of significant spin-orbit coupling for the
underlying electrons. Nonetheless, spectroscopic evidence for flat bands
engendered by lattice geometry rather than weak hopping is rare, particularly
for metallic single crystals. Here we report the discovery, using circularly
polarized X-Rays in resonant absorption and inelastic scattering (RIXS) for the
unambiguous isolation of magnetic signals, of a flat spin wave band and large
orbital moment for the metallic kagome ferromagnet Fe$_3$Sn$_2$, which has a
topologically non-trivial electronic band structure controllable by modest
external magnetic fields. The flat mode energy is consistent with the high
Curie temperature ($T_C$ ~ 640 K) as well as the strong acoustic mode
dispersion, implying, together with the substantial spin-orbit coupling
indicated by the large orbital moment, that the mode is topological. The
measured properties of the spin waves are highly unconventional, and include
very severe damping as well as the flat mode amplitude which is maximized in
the long wavelength limit where it is ordinarily expected to vanish. Our
results open the topic of interactions of topological bosons (spin waves) and
fermions (electrons) with the very specific target of explaining boson
lifetimes and amplitudes.",2302.01457v1
2020-03-23,Gravitational Waves and Possible Fast Radio Bursts from Axion Clumps,"The axion objects such as axion mini-clusters and axion clouds around
spinning black holes induce parametric resonances of electromagnetic waves
through the axion-photon interaction. In particular, it has been known that the
resonances from the axion with the mass around $10^{-6}$eV may explain the
observed fast radio bursts (FRBs). Here we argue that similar bursts of high
frequency gravitational waves, which we call the fast gravitational wave bursts
(FGBs), are generated from axion clumps with the presence of gravitational
Chern-Simons (CS) coupling. The typical frequency is half of the axion mass,
which in general can range from kHz to GHz. We also discuss the secondary
gravitational wave production associated with FRB, as well as the possible host
objects of the axion clouds, such as primordial black holes with typical masses
around $10^{-5}M_{\odot}$. Future detections of FGBs together with the observed
FRBs are expected to provide more evidence for the axion.",2003.10527v3
2003-04-30,All-sky upper limit for gravitational radiation from spinning neutron stars,"We present results of the all-sky search for gravitational-wave signals from
spinning neutron stars in the data of the EXPLORER resonant bar detector. Our
data analysis technique was based on the maximum likelihood detection method.
We briefly describe the theoretical methods that we used in our search. The
main result of our analysis is an upper limit of ${\bf 2\times10^{-23}}$ for
the dimensionless amplitude of the continuous gravitational-wave signals coming
from any direction in the sky and in the narrow frequency band from 921.00 Hz
to 921.76 Hz.",0304107v1
2016-10-13,Spin-wave spectra in periodically surface-modulated ferromagnetic thin films,"This article presents theoretical results for the dynamic response of
periodically surface-modulated ferromagnetic thin films. For such system, the
role of the periodic dipolar field induced by the modulation is addressed by
using the plane-wave method. By controlling the geometry of the modulated
volumes within the film, the frequency modes and spatial profiles of spin waves
can be manipulated. The angular dependence of the frequency band-gaps unveils
the influence of both dynamic and static magnetic charges, which reside in the
edges of the etching periodic zones, and it is stablished that band-gap widths
created by static magnetic charges are broader than the one created by dynamic
magnetic charges. To corroborate the validity of the model, the theoretical
results are compared with ferromagnetic resonance simulations, where a very
good agreement is achieved between both methods. The theoretical model allows
for a detailed understanding of the physics underlying these kind of systems,
thereby providing an outlook to potential applications associated with magnonic
crystals-based devices.",1610.04176v1
2020-11-10,High efficient metasurface quarter-wave plate with wavefront engineering,"Metasurfaces with local phase tuning by subwavelength elements promise
unprecedented possibilities for ultra-thin and multifunctional optical devices,
in which geometric phase design is widely used due to its resonant-free and
large tolerance in fabrications. By arranging the orientations of anisotropic
nano-antennas, the geometric phase-based metasurfaces can convert the incident
spin light to its orthogonal state, and enable flexible wavefront engineering
together with the function of a half-wave plate. Here, by incorporating the
propagation phase, we realize another important optical device of quarter-wave
plate together with the wavefront engineering as well, which is implemented by
controlling both the cross- and co-polarized light simultaneously with a
singlet metasurface. Highly efficient conversion of the spin light to a variety
of linearly polarized light are obtained for meta-holograms, metalens focusing
and imaging in blue light region. Our work provides a new strategy for
efficient metasurfaces with both phase and polarization control, and enriches
the functionalities of metasurface devices for wider application scenarios.",2011.05116v1
2019-12-12,Topological $\mathbb{Z}_2$ RVB quantum spin liquid on the ruby lattice,"We construct a short-range resonating valence-bond state (RVB) on the ruby
lattice, using projected entangled-pair states (PEPS) with bond dimension
$D=3$. By introducing non-local moves to the dimer patterns on the torus, we
distinguish four distinct sectors in the space of dimer coverings, which is a
signature of the topological nature of the RVB wave function. Furthermore, by
calculating the reduced density matrix of a bipartition of the RVB state on an
infinite cylinder and exploring its entanglement entropy, we confirm the
topological nature of the RVB wave function by obtaining non-zero topological
contribution, $\gamma=-\rm{ln}\ 2$, consistent with that of a $\mathbb{Z}_2$
topological quantum spin liquid. We also calculate the ground-state energy of
the spin-$\frac{1}{2}$ antiferromagnetic Heisenberg model on the ruby lattice
and compare it with the RVB energy. Finally, we construct a quantum-dimer model
for the ruby lattice and discuss it as a possible parent Hamiltonian for the
RVB wave function.",1912.06215v1
2020-07-30,Coherent multi-mode conversion from microwave to optical wave via a magnon-cavity hybrid system,"Coherent conversion from microwave to optical wave opens new research avenues
towards long distant quantum network covering quantum communication, computing,
and sensing out of the laboratory. Especially multi-mode enabled system is
essential for practical applications. Here we experimentally demonstrate
coherent multi-mode conversion from the microwave to optical wave via
collective spin excitation in a single crystal yttrium iron garnet (YIG,
Y3Fe5O12) which is strongly coupled to a microwave cavity mode in a
three-dimensional rectangular cavity. Expanding collective spin excitation mode
of our magnon-cavity hybrid system from Kittel to multi magnetostatic modes, we
verify that the size of YIG sphere predominantly plays a crucial role for the
microwave-to-optical multi-mode conversion efficiency at resonant conditions.
We also find that the coupling strength between multi magnetostatic modes and a
cavity mode is manipulated by the position of a YIG inside the cavity. It is
expected to be valuable for designing a magnon hybrid system that can be used
for coherent conversion between microwave and optical photons.",2007.15299v1
2023-04-16,Competing charge and magnetic order in the candidate centrosymmetric skyrmion host EuGa$_2$Al$_2$,"Eu(Ga$_{1-x}$Al$_x$)$_4$ are centrosymmetric systems that have recently been
identified as candidates to stabilise topologically non-trivial magnetic
phases, such as skyrmion lattices. In this Letter, we present a high-resolution
resonant x-ray and neutron scattering study on EuAl2Ga2 that provides new
details of the complex coupling between the electronic ordering phenomena. Our
results unambiguously demonstrate that the system orders to form a spin density
wave with moments aligned perpendicular to the direction of the propagation
vector, and upon further cooling, a cycloid with moments in the ab plane, in
contrast to what has been reported in the literature. We show that concomitant
with the onset of the spin density wave is the suppression of the charge order,
indicative of a coupling between the localised 4$f$ electrons and itinerant
electron density. Furthermore we demonstrate that the charge density wave order
breaks the four-fold symmetry present in the I4/mmm crystal structure, thus
declassifying these systems as square-net magnets.",2304.07903v2
2021-09-28,"Spin wave propagation in uniform waveguide: effects, modulation and its application","With the advent of the post-Moore era, researches on beyond-Complementary
Metal Oxide Semiconductor (CMOS) approaches have been attracted more and more
attention. Magnonics, or spin wave is one of the most promising technology
beyond CMOS, which magnons-quanta for spin waves-process the information
analogous to electronic charges in electronics. Information transmission by
spin waves, which uses the frequency, amplitude and (or) phase to encode
information, has a great many of advantages such as extremely low energy loss
and wide-band frequency. Moreover, using the nonlinear characteristics of spin
waves for information transmission can increase the extra degree of freedom of
information. This review provides a tutorial overview over the effects of spin
wave propagation and recent research progress in uniform spin wave waveguide.
The propagation characteristics of spin waves in uniform waveguides and some
special propagation phenomena such as spin wave beam splitting and
self-focusing are described by combining experimental phenomena and theoretical
formulas. Furthermore, we summarize methods for modulating propagation of spin
wave in uniform waveguide, and comment on the advantages and limitations of
these methods. The review may promote the development of information
transmission technology based on spin waves.",2109.13464v1
2008-09-14,Effects of the $g$-factor in semi-classical kinetic plasma theory,"A kinetic theory for spin plasmas is put forward, generalizing those of
previous authors. In the model, the ordinary phase space is extended to include
the spin degrees of freedom. Together with Maxwell's equations, the system is
shown to be energy conserving. Analysing the linear properties, it is found
that new types of wave-particle resonances are possible, that depend directly
on the anomalous magnetic moment of the electron. As a result new wave modes,
not present in the absence of spin, appear. The implications of our results are
discussed.",0809.2382v2
2012-10-18,Magnetic excitation spectra in pyrochlore iridates,"Metal-insulator transitions in pyrochlore iridates (A2Ir2O7) are believed to
occur due to subtle interplay of spin-orbit coupling, geometric frustration,
and electron interactions. In particular, the nature of magnetic ordering of
iridium ions in the insulating phase is crucial for understanding of several
exotic phases recently proposed for these materials. We study the spectrum of
magnetic excitations in the intermediate-coupling regime for the so-called
all-in/all-out magnetic state in pyrochlore iridates with non-magnetic A-site
ions (A=Eu,Y), which is found to be preferred in previous theoretical studies.
We find that the effect of charge fluctuations on the spin-waves in this regime
leads to strong departure from the lowest-order spin-wave calculations based on
models obtained in strong-coupling calculations. We discuss the characteristic
features of the magnetic excitation spectrum that can lead to conclusive
identification of the magnetic order in future resonant inelastic x-ray (or
neutron) scattering experiments. Knowledge of the nature of magnetic order and
its low-energy features may also provide useful information on the accompanying
metal-insulator transition.",1210.5242v2
2014-05-13,Spin oscillations of relativistic fermions in the field of a traveling circularly polarized electromagnetic wave and a constant magnetic field,"The Dirac equation, in the field of a traveling circularly polarized
electromagnetic wave and a constant magnetic field, has singular solutions,
corresponding the expansion of energy in vicinity of some singular point. These
solutions described relativistic fermions. States relating to these solutions
are not stationary. The temporal change of average energy, momentum and spin
for single and mixed states is studied in the paper. A distinctive feature of
the states is the disappearance of the longitudinal component of the average
spin. Another feature is the equivalence of the condition of fermion minimal
energy and the classical condition of the magnetic resonance. Finding such
solutions assumes the use of a transformation for rotating and co-moving frames
of references. Comparison studies of solutions obtained with the Galilean and
non-Galilean transformation shown that some parameters of the non-Galilean
transformation may be measured in high-energy physics.",1405.3613v1
2016-02-18,"Zitterbewegung, internal momentum and spin of the circular travelling wave electromagnetic electron","The study of this paper demonstrates that electron has Dirac delta like
internal momentum (u,p_{{\theta}}), going round in a circle of radius equal to
half the reduced Compton wavelength of electron with tangential velocity c. The
circular momentum p_{{\theta}} and energy u emanate from circular Dirac delta
type rotating monochromatic electromagnetic (EM) wave that itself travels in
another circle having radius equal to the reduced Compton wavelength of
electron. The phenomenon of Zitterbewegung and the spin of electron are the
natural consequences of the model. The spin is associated with the internal
circulating momentum of electron in terms of four component spinor, which leads
to the Dirac equation linking the EM electron model with quantum mechanical
theory. Our model accurately explains the experimental results of electron
channelling experiment, [P. Catillon et al., Found.Phys. 38, 659 (2008)], in
which the momentum resonance is observed at 161.784MeV/c corresponding to
Zitterbewegung frequency of 80.874MeV/c electron beam.",1602.07534v1
2019-05-04,Identification and time-resolved study of YIG spin wave modes in a MW cavity in strong coupling regime,"Recently, the hybridization of microwave-frequency cavity modes with
collective spin excitations attracted large interest for the implementation of
quantum computation protocols, which exploit the transfer of information among
these two physical systems. Here, we investigate the interaction among the
magnetization precession modes of a small YIG sphere and the MW electromagnetic
modes, resonating in a tridimensional aluminum cavity. In the strong coupling
regime, anti-crossing features were observed in correspondence of various
magnetostatic modes, which were excited in a magnetically saturated sample.
Time-resolved studies show evidence of Rabi oscillations, demonstrating
coherent exchange of energy among photons and magnons modes. To facilitate the
analysis of the standing spin-wave patterns, we propose here a new procedure,
based on the introduction of a novel functional variable. The resulting easier
identification of magnetostatic modes can be exploited to investigate, control
and compare many-levels hybrid systems in cavity- and opto-magnonics research.",1905.01522v2
2017-03-27,Anisotropic exchange and spin-wave damping in pure and electron-doped Sr$_2$IrO$_4$,"The collective magnetic excitations in the spin-orbit Mott insulator
(Sr$_{1-x}$La$_x$)$_2$IrO$_4$ ($x=0,\,0.01,\,0.04,\, 0.1$) were investigated by
means of resonant inelastic x-ray scattering. We report significant magnon
energy gaps at both the crystallographic and antiferromagnetic zone centers at
all doping levels, along with a remarkably pronounced momentum-dependent
lifetime broadening. The spin-wave gap is accounted for by a significant
anisotropy in the interactions between $J_\text{eff}=1/2$ isospins, thus
marking the departure of Sr$_2$IrO$_4$ from the essentially isotropic
Heisenberg model appropriate for the superconducting cuprates.",1703.09051v4
2019-10-03,Neutrino oscillations in gravitational waves,"We study spin and flavor oscillations of neutrinos under the influence of
gravitational waves (GWs). We rederive the quasiclassical equation for the
evolution of the neutrino spin in various external fields in curved spacetime
starting from the Dirac equation for a massive neutrino. Then, we consider
neutrino spin oscillations in nonmoving and unpolarized matter, a transverse
magnetic field, and a plane GW. We show that a parametric resonance can take
place in this system. We also study neutrino flavor oscillations in GWs. The
equation for the density matrix of flavor neutrinos is solved when we discuss
the neutrino interaction with stochastic GWs emitted by coalescing supermassive
black holes. We find the fluxes of cosmic neutrinos, undergoing flavor
oscillations in such a gravitational background, which can be potentially
measured by a terrestrial detector. Some astrophysical applications of our
results are considered.",1910.01415v1
1999-06-10,Hall-like effect induced by spin-orbit interaction,"The effect of spin-orbit interaction on electron transport properties of a
cross-junction structure is studied. It is shown that it results in spin
polarization of left and right outgoing electron waves. Consequently, incoming
electron wave of a proper polarization induces voltage drop perpendicularly to
the direct current flow between source and drain of the considered
four-terminal cross-structure. The resulting Hall-like resistance is estimated
to be of the order of 10^-3 - 10^-2 h/e^2 for technologically available
structures. The effect becomes more pronounced in the vicinity of resonances
where Hall-like resistance changes its sign as function of the Fermi energy.",9906151v1
2000-02-01,Spin Dynamics and Orbital State in LaTiO_3,"A neutron scattering study of the Mott-Hubbard insulator LaTiO$_{3}$
(T$_{{\rm N}}=132$ K) reveals a spin wave spectrum that is well described by a
nearest-neighbor superexchange constant $J=15.5$ meV and a small
Dzyaloshinskii-Moriya interaction ($D=1.1$ meV). The nearly isotropic spin wave
spectrum is surprising in view of the absence of a static Jahn-Teller
distortion that could quench the orbital angular momentum, and it may indicate
strong orbital fluctuations. A resonant x-ray scattering study has uncovered no
evidence of orbital order in LaTiO$_{3}$.",0002014v2
2013-07-20,Microscopic coexistence of a two-component incommensurate spin density wave with superconductivity in underdoped NaFe$_{0.983}$Co$_{0.017}$As,"We have performed $^{75}$As and $^{23}$Na nuclear magnetic resonance (NMR)
measurements on a single crystal of NaFe$_{0.9835}$Co$_{0.0165}$As and found
microscopic coexistence of superconductivity with a two-component spin density
wave (SDW). Using $^{23}$Na NMR we measured the spatial distribution of local
magnetic fields. The SDW was found to be incommensurate with a major component
having magnetic moment ($\sim0.2\,\mu_B$/Fe) and a smaller component with
magnetic moment ($\sim0.02\,\mu_B$/Fe). Spin lattice relaxation experiments
reveal that this coexistence occurs at a microscopic level.",1307.5366v1
2015-12-15,Optical emission spectroscopy study of competing phases of electrons in the second Landau level,"Quantum phases of electrons in the filling factor range $2 \leq\nu\leq 3$ are
probed by the weak optical emission from the partially populated second Landau
level and spin wave measurements. Observations of optical emission include a
multiplet of sharp peaks that exhibit a strong filling factor dependence. Spin
wave measurements by resonant inelastic light scattering probe breaking of spin
rotational invariance and are used to link this optical emission with
collective phases of electrons. A remarkably rapid interplay between emission
peak intensities manifests phase competition in the second Landau level.",1512.04914v1
2016-08-21,The Unusual Nature of Confined Modes in a Chiral System,"Nonreciprocity of spin wave propagation is a well-known consequence of
antisymmetric exchange contributions possible in magnetic spin systems that
lack inversion symmetry. In this case, it is possible for the energy of a state
to depend on the sign of its momentum as {\omega}(k) ${\neq}$ {\omega}(-k). We
discuss here the consequences of this nonreciprocity on counterpropagating
travelling spin wave states. In a confined geometry we find states with
well-defined nodes but with amplitudes that are modulated such that inversion
symmetry of the mode profile is lost. This feature leads to the suggestion that
additional features may become visible in, for example, ferromagnetic resonance
studies of ferromagnetic micro-elements with DMI, allowing a quantification of
the amplitude and direction of the DMI. Moreover, this interference between
nonreciprocal modes forms the basis for a generalized concept of mode
confinement.",1609.03417v1
2020-04-23,Damping of gravitational waves in 2-2-holes,"A 2-2-hole is an explicit realization of a horizonless object that can still
very closely resemble a BH. An ordinary relativistic gas can serve as the
matter source for the 2-2-hole solution of quadratic gravity, and this leads to
a calculable area-law entropy. Here we show that it also leads to an estimate
of the damping of a gravitational wave as it travels to the center of the
2-2-hole and back out again. We identify two frequency dependent effects that
greatly diminish the damping. Spinning 2-2-hole solutions are not known, but we
are still able to consider some spin dependent effects. The frequency and spin
dependence of the damping helps to determine the possible echo resonance signal
from the rotating remnants of merger events. It also controls the fate of the
ergoregion instability.",2004.11285v3
2022-03-18,"Interplay of charge density waves, disorder, and superconductivity in 2$H$-TaSe$_2$ elucidated by NMR","Single crystals of pristine and 6% Pd-intercalated 2H-TaSe$_2$ have been
studied by means of $^{77}$Se nuclear magnetic resonance (NMR). The temperature
dependence of the $^{77}$Se spectrum, with an unexpected line narrowing upon Pd
intercalation, unravels the presence of correlated local lattice distortions
far above the transition temperature of the charge density wave (CDW) order,
thereby supporting a strong-coupling CDW mechanism in 2H-TaSe$_2$. While, the
Knight shift data suggest that the incommensurate CDW transition involves a
partial Fermi surface gap opening. As for spin dynamics, the $^{77}$Se
spin-lattice relaxation rate $T_1^{-1}$ as a function of temperature shows that
a pseudogap behavior dominates the low-energy spin excitations even within the
CDW phase, and gets stronger along with superconductivity in the Pd-6% sample.
We discuss that CDW fluctuations may be responsible for the pseudogap as well
as superconductivity, although the two phenomena are unlikely to be directly
linked each other.",2203.09662v1
2012-06-04,Effects of Zeroline and Ferrimagnetic Fluctuation on Nuclear Magnetic Resonance for Dirac Electrons in Molecular Conductor alpha-(BEDT-TTF)2I3,"We re-examine the wave function of two-dimensional massless Dirac electron in
alpha-(BEDT-TTF)2I3 consisting of four molecules A, A', B and C in a unit cell,
using a tight-binding model. We find zerolines in the Brillouin zone, on which
the component of the wave function becomes zero for B or C sites. The
zerolines, which are bounded by two Dirac points at k0 and pass through the M-
or Y-points, result in a fact that the density of states of the B site exhibits
no the Van Hove singularity near the energy of the Dirac points. By taking
account of the on-site Coulomb interaction within the random phase
approximation, we examine the spin fluctuation in order to investigate
properties of the nuclear magnetic resonance for temperatures T > 50K. In the
region for 100 < T < 300K, it is shown that the Knight sift for B-site
monotonously decreases with decreasing temperature, owing to lack of the Van
Hove singularity, while it shows a maximum for the other sites (A, A' and C
sites). In the region for 50 < T < 100K, it is shown that the Knight sift is
convex downward and the Korringa ratio increases with decreasing temperature
for B-site. Such a behavior originates from the ferrimagnetic spin fluctuation
related to the zerolines. These results are consistent with those of the
nuclear magnetic resonance experiments.",1206.0527v1
2019-03-13,Nutation spectroscopy of a nanomagnet driven into deeply nonlinear ferromagnetic resonance,"Strongly out-of-equilibrium regimes in magnetic nanostructures exhibit novel
properties, linked to the nonlinear nature of magnetization dynamics, which are
of great fundamental and practical interest. Here, we demonstrate that
field-driven ferromagnetic resonance can occur with substantial spatial
coherency at unprecedented large angle of magnetization precessions, which is
normally prevented by the onset of spin-wave instabilities and magnetization
turbulent dynamics. Our results show that this limitation can be overcome in
nanomagnets, where the geometric confinement drastically reduces the density of
spin-wave modes. The obtained deeply nonlinear ferromagnetic resonance regime
is probed by a new spectroscopic technique based on the application of a second
excitation field. This enables to resonantly drive slow coherent magnetization
nutations around the large angle periodic trajectory. Our experimental findings
are well accounted for by an analytical model derived for systems with uniaxial
symmetry. They also provide new means for controlling highly nonlinear
magnetization dynamics in nanostructures, which open interesting applicative
opportunities in the context of magnetic nanotechnologies.",1903.05411v1
2021-04-16,Strong magnon-photon coupling with chip-integrated YIG in the zero-temperature limit,"The cross-integration of spin-wave and superconducting technologies is a
promising method for creating novel hybrid devices for future information
processing technologies to store, manipulate, or convert data in both classical
and quantum regimes. Hybrid magnon-polariton systems have been widely studied
using bulk Yttrium Iron Garnet (Y$_{3}$Fe$_{5}$O$_{12}$, YIG) and
three-dimensional microwave photon cavities. However, limitations in YIG growth
have thus far prevented its incorporation into CMOS compatible technology such
as high quality factor superconducting quantum technology. To overcome this
impediment, we have used Plasma Focused Ion Beam (PFIB) technology -- taking
advantage of precision placement down to the micron-scale -- to integrate YIG
with superconducting microwave devices. Ferromagnetic resonance has been
measured at millikelvin temperatures on PFIB-processed YIG samples using planar
microwave circuits. Furthermore, we demonstrate strong coupling between
superconducting resonator and YIG ferromagnetic resonance modes by maintaining
reasonably low loss while reducing the system down to the micron scale. This
achievement of strong coupling on-chip is a crucial step toward fabrication of
functional hybrid quantum devices that advantage from spin-wave and
superconducting components.",2104.08068v3
2005-02-23,Spin tune in the single resonance model with a pair of Siberian Snakes,"Snake ``resonances'' are classified in terms of the invariant spin field and
the amplitude dependent spin tune. Exactly at snake ``resonance'' there is no
continuous invariant spin field at most orbital amplitudes.",0502121v1
2001-10-10,Magnetic Resonance Force Microscopy Measurement of Entangled Spin States,"We simulate magnetic resonance force microscopy measurements of an entangled
spin state. One of the entangled spins drives the resonant cantilever
vibrations, while the other remote spin does not interact directly with the
quasiclassical cantilever. The Schr\""odinger cat state of the cantilever
reveals two possible outcomes of the measurement for both entangled spins.",0110070v1
2012-08-09,Interference-mediated intensity modulation of spin waves,"The modulation of propagating spin-wave amplitude in Ni81Fe19 (Py) films,
resulting from constructive and destructive interference of spin wave, has been
demonstrated. Spin waves were excited and detected inductively using pulse
inductive time domain measurements. Two electrical impulses were used for
launching two interfering Gaussian spin wave packets in Py films. The applied
bias magnetic field or the separation between two pulses was used for tuning
the amplitude of the resulting spin wave packets. This may thus be useful for
spin wave based low-power information transfer and processing.",1208.1848v1
2019-08-28,Effect of inhomogeneous Dzyaloshinskii-Moriya interaction on antiferromagnetic spin-wave propagation,"We investigate the effect of inhomogeneous Dzyaloshinskii-Moriya interaction
(DMI) on antiferromagnetic spin-wave propagation theoretically and numerically.
We find that antiferromagnetic spin waves can be amplified at a boundary where
the DMI varies. The inhomogeneous DMI also provides a way to construct a
magnonic crystal with forbidden and allowed antiferromagnetic spin-wave bands
in terahertz frequency ranges. In contrast to ferromagnetic spin waves,
antiferromagnetic spin waves experience a polarization-dependent phase shift
when passing through the inhomogeneous DMI, offering a magnonic crystal that
also serves as a spin-wave polarizer.",1908.10650v1
2021-12-07,Curvilinear manipulation of polarized spin wave,"Polarization, the precession direction with respect to the background
magnetization, is an intrinsic degree of freedom of spin wave. Introducing
symmetry breaking mechanisms lies in the heart of lifting the degeneracy
between polarized spin wave modes, and is essential in constructing
polarization-based magnonic devices. Here we show that polarized spin waves can
be naturally harnessed in a curved antiferromagnetic wire via tuning its
curvature and torsion. Specifically, we investigate evolution of polarized spin
wave in a spin wave rotator and a spin wave interferometer based on magnetic
circular helices, and correlate these curvilinear effects to the Berry phase
accumulated along wires.",2112.03748v1
2005-02-25,Bosonic resonating valence bond wave function for doped Mott insulators,"We propose a new class of ground states for doped Mott insulators in the
electron second-quantization representation. They are obtained from a bosonic
resonating valence bond (RVB) theory of the t-J model. At half filling, the
ground state describes spin correlations of the S=1/2 Heisenberg model very
accurately. Its spin degrees of freedom are characterized by RVB pairing of
spins, the size of which decreases continuously as holes are doped into the
system. Charge degrees of freedom emerge upon doping and are described by
twisted holes in the RVB background. We show that the twisted holes exhibit an
off diagonal long range order (ODLRO) in the pseudogap ground state, which has
a finite pairing amplitude, but is short of phase coherence. Unpaired spins in
such a pseudogap ground state behave as free vortices, preventing
superconducting phase coherence. The existence of nodal quasiparticles is also
ensured by such a hidden ODLRO in the ground state, which is
non-Fermi-liquid-like in the absence of superconducting phase coherence. Two
distinct types of spin excitations can also be constructed. The superconducting
instability of the pseudogap ground state is discussed and a d-wave
superconducting ground state is obtained. This class of pseudogap and
superconducting ground states unifies antiferromagnetism, pseudogap,
superconductivity, and Mott physics into a new state of matter.",0502601v2
1999-05-28,Electron Spin Resonance Transistors for Quantum Computing in Silicon-Germanium Heterostructures,"We apply the full power of modern electronic band structure engineering and
epitaxial heterostructures to design a transistor that can sense and control a
single donor electron spin. Spin resonance transistors may form the
technological basis for quantum information processing. One and two qubit
operations are performed by applying a gate bias. The bias electric field pulls
the electron wave function away from the dopant ion into layers of different
alloy composition. Owing to the variation of the g-factor (Si:g=1.995,
Ge:g=1.563), this displacement changes the spin Zeeman energy, allowing
single-qubit operations. By displacing the electron even further, the overlap
with neighboring qubits is affected, which allows two-qubit operations. Certain
Silicon-Germanium alloys allow a qubit spacing as large as 200 nm, which is
well within the capabilities of current lithographic techniques. We discuss
manufacturing limitations and issues regarding scaling up to a large size
computer.",9905096v2
2012-05-16,Polarized neutron scattering studies of magnetic excitations in electron-overdoped superconducting BaFe$_{1.85}$Ni$_{0.15}$As$_{2}$,"We use polarized inelastic neutron scattering to study low-energy spin
excitations and their spatial anisotropy in electron-overdoped superconducting
BaFe$_{1.85}$Ni$_{0.15}$As$_{2}$ ($T_c=14$ K). In the normal state, the
imaginary part of the dynamic susceptibility, $\chi^{\prime\prime}(Q,\omega)$,
at the antiferromagnetic (AF) wave vector $Q=(0.5,0.5,1)$ increases linearly
with energy for $E\le 13$ meV. Upon entering the superconducting state, a spin
gap opens below $E\approx 3$ meV and a broad neutron spin resonance appears at
$E\approx 7$ meV. Our careful neutron polarization analysis reveals that
$\chi^{\prime\prime}(Q,\omega)$ is isotropic for the in-plane and out-of-plane
components in both the normal and superconducting states. A comparison of these
results with those of undoped BaFe$_2$As$_2$ and optimally electron-doped
BaFe$_{1.9}$Ni$_{0.1}$As$_{2}$ ($T_c=20$ K) suggests that the spin anisotropy
observed in BaFe$_{1.9}$Ni$_{0.1}$As$_{2}$ is likely due to its proximity to
the undoped BaFe$_2$As$_2$. Therefore, the neutron spin resonance is isotropic
in the overdoped regime, consistent with a singlet to triplet excitation.",1205.3730v1
2017-06-14,Nonlocal magnon-polaron transport in yttrium iron garnet,"The spin Seebeck effect (SSE) is observed in magnetic insulator|heavy metal
bilayers as an inverse spin Hall effect voltage under a temperature gradient.
The SSE can be detected nonlocally as well, viz. in terms of the voltage in a
second metallic contact (detector) on the magnetic film, spatially separated
from the first contact that is used to apply the temperature bias (injector).
Magnon-polarons are hybridized lattice and spin waves in magnetic materials,
generated by the magnetoelastic interaction. Kikkawa et al. [Phys. Rev. Lett.
\textbf{117}, 207203 (2016)] interpreted a resonant enhancement of the local
SSE in yttrium iron garnet (YIG) as a function of the magnetic field in terms
of magnon-polaron formation. Here we report the observation of magnon-polarons
in \emph{nonlocal} magnon spin injection/detection devices for various
injector-detector spacings and sample temperatures. Unexpectedly, we find that
the magnon-polaron resonances can suppress rather than enhance the nonlocal
SSE. Using finite element modelling we explain our observations as a
competition between the SSE and spin diffusion in YIG. These results give
unprecedented insights into the magnon-phonon interaction in a key magnetic
material.",1706.04373v1
2020-03-06,Acoustically driving the single quantum spin transition of diamond nitrogen-vacancy centers,"Using a high quality factor 3 GHz bulk acoustic wave resonator device, we
demonstrate the acoustically driven single quantum spin transition
($\left|m_{s}=0\right>\leftrightarrow\left|\pm1\right>$) for diamond NV centers
and characterize the corresponding stress susceptibility. A key challenge is to
disentangle the unintentional magnetic driving field generated by device
current from the intentional stress driving within the device. We quantify
these driving fields independently using Rabi spectroscopy before studying the
more complicated case in which both are resonant with the single quantum spin
transition. By building an equivalent circuit model to describe the device's
current and mechanical dynamics, we quantitatively model the experiment to
establish their relative contributions and compare with our results. We find
that the stress susceptibility of the NV center spin single quantum transition
is around $\sqrt{2}(0.5\pm0.2)$ times that for double quantum transition
($\left|+1\right>\leftrightarrow\left|-1\right>$). Although acoustic driving in
the double quantum basis is valuable for quantum-enhanced sensing applications,
double quantum driving lacks the ability to manipulate NV center spins out of
the $\left|m_{s}=0\right>$ initialization state. Our results demonstrate that
efficient all-acoustic quantum control over NV centers is possible, and is
especially promising for sensing applications that benefit from the compact
footprint and location selectivity of acoustic devices.",2003.03418v1
2023-12-13,Parametric Frequency Divider based Ising Machines,"We report on a new class of Ising Machines (IMs) that rely on coupled
parametric frequency dividers (PFDs) as macroscopic artificial spins. Unlike
the IM counterparts based on subharmonic injection locking (SHIL), PFD IMs do
not require strong injected continuous wave signals or applied DC voltages.
Therefore, they show a significantly lower power consumption per spin compared
to SHIL based IMs, making it feasible to accurately solve large scale
combinatorial optimization problems (COPs) that are hard or even impossible to
solve by using the current von Neumann computing architectures. Furthermore,
using high quality (Q) factor resonators in the PFD design makes PFD IMs able
to exhibit a nanoWatt level power per spin. Also, it remarkably allows a speed
up of the phase synchronization among the PFDs, resulting in shorter time to
solution and lower energy to solution despite the resonators' longer relaxation
time. As a proof of concept, a 4 node PFD IM has been demonstrated. This IM
correctly solves a set of MaxCut problems while consuming just 600 nanoWatts
per spin. This power consumption is two orders of magnitude lower than the
power per spin of state of the art SHIL based IMs operating at the same
frequency.",2312.08329v2
2011-03-24,Spin wave assisted current induced magnetic domain wall motion,"The interaction between the propagating spin waves and the current driven
motion of a transverse domain wall in magnetic nanowires is studied by
micromagnetic simulations. If the speed of domain walls due to current induced
spin transfer torque is comparable to the velocity driven by spin waves, the
speed of domain wall is improved by applying spin waves. The domain wall
velocity can be manipulated by the frequency and amplitude of spin waves. The
effect of spin waves is suppressed in the high current density regime in which
the domain wall is mostly driven by current induced spin transfer torque.",1103.4673v1
2017-04-04,Gravity Induced Resonant Emission,"The gravitational drift of ions relative to the electrons induces two type of
waves in magnetized plasma; ion acoustic (IO) waves and lower hybrid (LH)
waves. The IO waves induced by the gravity are damped by electromagnetic (EM)
waves leads to the formation of LH waves. For higher wave vector, these LH wave
results in to the resonant absorption and re-emission of EM waves, called as
gravity induced resonant emission (gire). A general formula has been derived
for gire frequency is convergence of all fundamental quantities.",1704.07225v1
2011-06-26,Quantum Field Effects in Stationary Electron Spin Resonance Spectroscopy,"It is proved on the example of electron spin resonance (ESR) studies of
anthracites, that by strong electron-photon and electron-phonon interactions
the formation of the coherent system of the resonance phonons takes place.
  The acoustic quantum Rabi oscillations were observed for the first time in
ESR-spectroscopy. Its Rabi frequency value on the first damping stage was found
to be equal 920.6 kHz, being to be independent on the microwave power level in
the range 20 - 6 dB [0 dB corresponds to 100 mW]. By the subsequent increase of
the microwave power the stepwise transition to the phenomenon of nonlinear
quantum Rabi oscillations, characterised by splitting of the oscillation group
of lines into two subgroups with doubling of the total lines' number takes
place. Linewidth of an individual oscillation line becomes approximately the
twofold narrower, being to be equal the only to $0.004 \pm 0.001$ G.
  Along with the absorption process of EM-field energy the emission process was
observed. It was found, that the emission process is the realization of the
acoustic spin resonance, the source of acoustic wave power in which is the
system of resonance phonons, accumulated in the samples by the registration
with AFC.
  It has been found, that the lifetime of coherent state of a collective
subsystem of resonance phonons in anthracites is very long and even by room
temperature it is evaluated by the value exceeding 4.6 minutes.
  The model of new kinds of instantons was proposed. They are considered to be
similar in the mathematical structure to Su-Schrieffer-Heeger solitons with
""propagation"" direction along time $t$-axis instead of space $z$-axis.
  The proof, that the superconductivity state in the anthracite samples studied
is produced at the room temperature in ESR conditions in the accordance with
the theory of the quantised acoustic field, has experimentally been obtained.",1106.5221v3
2020-03-04,Excitation of f-modes during mergers of spinning binary neutron star,"Tidal effects have important imprints on gravitational waves (GWs) emitted
during the final stage of the coalescence of binaries that involve neutron
stars (NSs). Dynamical tides can be significant when NS oscillations become
resonant with orbital motion; understanding this process is important for
accurately modeling GW emission from these binaries, and for extracting NS
information from GW data. In this paper, we carry out a systematic study on the
tidal excitation of fundamental modes of spinning NSs in coalescencing
binaries, focusing on the case when the NS spin is anti-aligned with the
orbital angular momentum-where the tidal resonance is most likely to take
place. We first expand NS oscillations into stellar eigen-modes, and then
obtain a Hamiltonian that governs the tidally coupled orbit-mode evolution. We
next find a new approximation that can lead to analytic expressions of tidal
excitations to a high accuracy, and are valid in all regimes of the binary
evolution: adiabatic, resonant, and post-resonance. Using the method of
osculating orbits, we obtain semi-analytic approximations to the orbital
evolution and GW emission; their agreements with numerical results give us
confidence in on our understanding of the system's dynamics. In particular, we
recover both the averaged post-resonance evolution, which differs from the
pre-resonance point-particle orbit by shifts in orbital energy and angular
momentum, as well as instantaneous perturbations driven by the tidal motion.
Finally, we use the Fisher matrix technique to study the effect of dynamical
tides on parameter estimation. We find that the dynamical tides may potentially
provide an additional channel to study the physics of NSs. The method presented
in this paper is generic and not restricted to f mode; it can also be applied
to other types of tide.",2003.02373v2
2014-11-28,Superconducting properties and pseudogap from preformed Cooper pairs in the triclinic (CaFe$_{1-x}$Pt$_x$As)$_{10}$Pt$_3$As$_8$,"Using a combination of muon-spin relaxation ($\mu$SR), inelastic neutron
scattering (INS) and nuclear magnetic resonance (NMR), we investigated the
novel iron-based superconductor with a triclinic crystal structure
(CaFe$_{1-x}$Pt$_x$As)$_{10}$Pt$_3$As$_8$ (T$_{\rm c}$ = 13 K), containing
platinum-arsenide intermediary layers. The temperature dependence of the
superfluid density obtained from the $\mu$SR relaxation-rate measurements
indicates the presence of two superconducting gaps,
$\Delta_\text{1}\gg\Delta_\text{2}$. According to our INS measurements,
commensurate spin fluctuations are centered at the ($\pi$, 0) wave vector, like
in most other iron arsenides. Their intensity remains unchanged across
T$_\text{c}$, indicating the absence of a spin resonance typical for many
Fe-based superconductors. Instead, we observed a peak in the spin-excitation
spectrum around $\hslash\omega_0=\,$7 meV at the same wave vector, which
persists above T$_{\rm c}$ and is characterized by the ratio
$\hslash\omega_0/k_\text{B}T_\text{c}\approx\,$6.2, which is significantly
higher than typical values for the magnetic resonant modes in iron pnictides
(~4.3). The temperature dependence of magnetic intensity at 7 meV revealed an
anomaly around T* = 45 K related to the disappearance of this new mode. A
suppression of the spin-lattice relaxation rate, $1/T_1T$, observed by NMR
immediately below T* without any notable subsequent anomaly at T$_{\rm c}$,
indicates that T* could mark the onset of a pseudogap in
(CaFe$_{1-x}$Pt$_x$As)$_{10}$Pt$_3$As$_8$, which is likely associated with the
emergence of preformed Cooper pairs.",1411.7858v1
2016-11-18,"Description of the $^{11}$Li$(p,d){^{10}}$Li transfer reaction using structure overlaps from a full three-body model","Recent data on the differential angular distribution for the transfer
reaction $^{11}$Li(p,d)$^{10}$Li at $E/A=5.7$ MeV in inverse kinematics are
analysed within the DWBA reaction framework, using the overlap functions
calculated within a three-body model of $^{11}$Li. The weight of the different
$^{10}$Li configurations in the system's ground state is obtained from the
structure calculations unambiguously. The effect of the $^{9}$Li spin in the
calculated observables is also investigated. We find that, although all the
considered models succeed in reproducing the shape of the data, the magnitude
is very sensitive to the content of $p_{1/2}$ wave in the $^{11}$Li
ground-state wave function. Among the considered models, the best agreement
with the data is obtained when the $^{11}$Li ground state contains a $\sim$31\%
of $p_{1/2}$ wave in the $n$-$^9$Li subsystem. Although this model takes into
account explicitly the splitting of the $1^+$ and $2^+$ resonances due to the
coupling of the $p_{1/2}$ wave to the $3/2^-$ spin of the core, a similar
degree of agreement can be achieved with a model in which the $^{9}$Li spin is
ignored, provided that it contains a similar p-wave content.",1611.06000v3
2018-03-19,Internal spin resistance of spin batteries,"For spin batteries we introduce the concept of internal spin resistance which
quantifies the amount of backflow from the load to the battery. It allows to
relate through a Thevenin-Norton relation, spin current sources to spin
accumulation sources. The value of the internal spin resistance is derived
explicitly for several spin batteries based on spin injection, ferromagnetic
resonance or spin Hall effect.",1803.07101v1
2012-11-12,Cyclotron resonant interactions in cosmic particle accelerators,"A review is given for cyclotron resonant interactions in space plasmas. After
giving a simple formulation for the test particle approach, illustrative
examples for resonant interactions are given. It is shown that for obliquely
propagating whistler waves, not only fundamental cyclotron resonance, but also
other resonances, such as transit-time resonance, anomalous cyclotron
resonance, higher-harmonic cyclotron resonance, and even subharmonic resonance
can come into play. A few recent topics of cyclotron resonant interactions,
such as electron injection in shocks, cyclotron resonant heating of solar wind
heavy ions, and relativistic modifications, are also reviewed.",1211.2852v1
2011-09-27,Dispersion and damping of zone-boundary magnons in the noncentrosymmetric superconductor CePt3Si,"Inelastic neutron scattering (INS) is employed to study damped spin-wave
excitations in the noncentrosymmetric heavy-fermion superconductor CePt3Si
along the antiferromagnetic Brillouin-zone boundary in the low-temperature
magnetically ordered state. Measurements along the (1/2 1/2 L) and (H H 1/2-H)
reciprocal-space directions reveal deviations in the spin-wave dispersion from
the previously reported model. Broad asymmetric shape of the peaks in energy
signifies strong spin-wave damping by interactions with the particle-hole
continuum. Their energy width exhibits no evident anomalies as a function of
momentum along the (1/2 1/2 L) direction, which could be attributed to
Fermi-surface nesting effects, implying the absence of pronounced commensurate
nesting vectors at the magnetic zone boundary. In agreement with a previous
study, we find no signatures of the superconducting transition in the magnetic
excitation spectrum, such as a magnetic resonant mode or a superconducting spin
gap, either at the magnetic ordering wavevector (0 0 1/2) or at the zone
boundary. However, the low superconducting transition temperature in this
material still leaves the possibility of such features being weak and therefore
hidden below the incoherent background at energies ~0.1 meV, precluding their
detection by INS.",1109.5784v1
2018-07-15,K-matrix formulation of two-particle scattering in a wave guide in the presence of one-dimensional spin-orbit coupling,"The creation of artificial gauge fields in neutral ultracold atom systems has
opened the possibility to study the effects of spin-orbit coupling terms in
clean environments. This work considers the multi-channel scattering properties
of two atoms confined by a wave guide in the presence of spin-orbit coupling
terms within a K-matrix scattering framework. The tunability of resonances,
induced by the interplay of the external wave guide geometry, the interactions,
and the spin-orbit coupling terms, is demonstrated. Our results for the
K-matrix elements as well as partial and total reflection coefficients for two
identical fermions interacting through a finite-range interaction potential in
the singlet channel only are compared with those obtained for a strictly
one-dimensional effective low- energy Hamiltonian, which uses the effective
coupling constant derived in Zhang et al. [Scientific Reports 4, 1 (2014)] and
Zhang et al. [Phys. Rev. A 88, 053605 (2013)] as input. In the regime where the
effective Hamiltonian is applicable, good agreement is obtained, provided the
energy- dependence of the coupling constant is accounted for. Our approach
naturally describes the energy regime in which the bands associated with
excited transverse modes lie below a subset of the bands associated with the
lowest transverse modes. The threshold behavior is discussed and scattering
observables are linked to bound state properties.",1807.05564v2
2019-05-27,Modulation-resonance mechanism for surface waves in a two-layer fluid system,"We propose a Boussinesq-type model to study the surface/interfacial wave
manifestation of an underlying, slowly-varying, long-wavelength, baroclinic
flow in a two-layer, density-stratified system. The results of our model show
numerically that, under strong nonlinearity, surface waves, with their typical
wavenumber being the resonant $k_{\mathrm{res}}$, can be generated locally at
the leading edge of the underlying slowly-varying, long-wavelength baroclinic
flow. Here, the resonant $k_{\mathrm{res}}$ satisfies the class 3 triad
resonance condition among two short-mode waves and one long-mode wave in which
all waves propagate in the same direction. Moreover, when the slope of the
baroclinic flow is sufficiently small, only one spatially-localized
large-amplitude surface wave packet can be generated at the leading edge. This
localized surface wave packet becomes high in amplitude and large in group
velocity after the interaction with its surrounding waves. These results are
qualitatively consistent with various experimental observations including
resonant surface waves at the leading edge of an internal wave. Subsequently,
we propose a mechanism, referred to as the modulation-resonance mechanism,
underlying these surface phenomena, based on our numerical simulations. The
proposed modulation-resonance mechanism combines the linear modulation
(ray-based) theory for the spatiotemporal asymmetric behavior of surface waves
and the nonlinear class 3 triad resonance theory for the energy focusing of
surface waves around the resonant wavenumber $k_{\mathrm{res}}$ in Fourier
space.",1905.11344v1
2012-06-04,Electron doping evolution of the anisotropic spin excitations in BaFe2-xNixAs2,"We use inelastic neutron scattering to systematically investigate the
Ni-doping evolution of the low-energy spin excitations in BaFe2-xNixAs2
spanning from underdoped antiferromagnet to overdoped superconductor (0.03< x <
0.18). In the undoped state, the low-energy (<80 meV) spin waves of BaFe2As2
form transversely elongated ellipses in the [H, K] plane of the reciprocal
space. Upon Ni-doping, the c-axis magnetic exchange coupling is rapidly
suppressed and the momentum distribution of spin excitations in the [H, K]
plane is enlarged in both the transverse and longitudinal directions with
respect to the in-plane AF ordering wave vector of the parent compound. As a
function of increasing Ni-doping x, the spin excitation widths increase
linearly but with a larger rate along the transverse direction. These results
are in general agreement with calculations of dynamic susceptibility based on
the random phase approximation (RPA) in an itinerant electron picture. For
samples near optimal superconductivity at x= 0.1, a neutron spin resonance
appears in the superconducting state. Upon further increasing the
electron-doping to decrease the superconducting transition temperature Tc, the
intensity of the low-energy magnetic scattering decreases and vanishes
concurrently with vanishing superconductivity in the overdoped side of the
superconducting dome. Comparing with the low-energy spin excitations centered
at commensurate AF positions for underdoped and optimally doped materials
(x<0.1), spin excitations in the over-doped side (x=0.15) form transversely
incommensurate spin excitations, consistent with the RPA calculation.
Therefore, the itinerant electron approach provides a reasonable description to
the low-energy AF spin excitations in BaFe2-xNixAs2.",1206.0653v2
2016-01-05,On the rich eight branch spectrum of the oblique propagating longitudinal waves in partially spin polarized electron-positron-ion plasmas,"We consider the separate spin evolution of electrons and positrons in
electron-positron and electron-positron-ion plasmas. We consider oblique
propagating longitudinal waves in this systems. We report presence of the
spin-electron acoustic waves and their dispersion dependencies. In
electron-positron plasmas, similarly to the electron-ion plasmas, we find one
spin-electron acoustic wave (SEAW) at propagation parallel or perpendicular to
the external field and two spin-electron acoustic waves at the oblique
propagation. At the parallel or perpendicular propagation of the longitudinal
waves in electron-positron-ion plasmas we find four branches: the Langmuir
wave, the positron-acoustic wave and pair of waves having spin nature, they are
the SEAW and, as we called it, spin-electron-positron acoustic wave (SEPAW). At
the oblique propagation we find eight longitudinal waves: the Langmuir wave,
Trivelpiece-Gould wave, pair of positron-acoustic waves, pair of SEAWs, and
pair of SEPAWs. Thus, for the first time, we report existence of the second
positron-acoustic wave existing at the oblique propagation and existence of
SEPAWs.",1601.00761v1
2010-09-24,Transient resonances in the inspirals of point particles into black holes,"We show that transient resonances occur in the two body problem in general
relativity, in the highly relativistic, extreme mass-ratio regime for spinning
black holes. These resonances occur when the ratio of polar and radial orbital
frequencies, which is slowly evolving under the influence of gravitational
radiation reaction, passes through a low order rational number. At such points,
the adiabatic approximation to the orbital evolution breaks down, and there is
a brief but order unity correction to the inspiral rate. Corrections to the
gravitational wave signal's phase due to resonance effects scale as the square
root of the inverse of mass of the small body, and thus become large in the
extreme-mass-ratio limit, dominating over all other post-adiabatic effects. The
resonances make orbits more sensitive to changes in initial data (though not
quite chaotic), and are genuine non-perturbative effects that are not seen at
any order in a standard post-Newtonian expansion. Our results apply to an
important potential source of gravitational waves, the gradual inspiral of
white dwarfs, neutron stars, or black holes into much more massive black holes.
It is hoped to exploit observations of these sources to map the spacetime
geometry of black holes. However, such mapping will require accurate models of
binary dynamics, which is a computational challenge whose difficulty is
significantly increased by resonance effects. We estimate that the resonance
phase shifts will be of order a few tens of cycles for mass ratios $\sim
10^{-6}$, by numerically evolving fully relativistic orbital dynamics
supplemented with an approximate, post-Newtonian self-force.",1009.4923v3
2016-07-21,Spin wave and spin flip in hexagonal LuMnO3 single crystal,"Manipulate and control of spin wave and spin flip are crucial for future
developments of magnonic and spintronic devices. We present that the spin wave
in hexagonal LuMnO3 single crystal can be selectively excited with laser
polarization perpendicular to the c-axis of hexagonal LuMnO3 and photon energy
~ 1.8 eV. The selective excitation of spin wave also suggests that the spin
flip can be selectively controlled in hexagonal manganites. In addition, the
physical origin of spin wave correlated with spin flip in hexagonal manganites
is discussed.",1607.06212v1
2017-07-16,The Cosmic Axion Spin Precession Experiment (CASPEr): a dark-matter search with nuclear magnetic resonance,"The Cosmic Axion Spin Precession Experiment (CASPEr) is a nuclear magnetic
resonance experiment (NMR) seeking to detect axion and axion-like particles
which could make up the dark matter present in the universe. We review the
predicted couplings of axions and axion-like particles with baryonic matter
that enable their detection via NMR. We then describe two measurement schemes
being implemented in CASPEr. The first method, presented in the original CASPEr
proposal, consists of a resonant search via continuous-wave NMR spectroscopy.
This method offers the highest sensitivity for frequencies ranging from a few
Hz to hundreds of MHz, corresponding to masses $ m_{\rm a} \sim
10^{-14}$--$10^{-6}$ eV. Sub-Hz frequencies are typically difficult to probe
with NMR due to the diminishing sensitivity of magnetometers in this region. To
circumvent this limitation, we suggest new detection and data processing
modalities. We describe a non-resonant frequency-modulation detection scheme,
enabling searches from mHz to Hz frequencies ($m_{\rm a} \sim
10^{-17}$--$10^{-14} $ eV), extending the detection bandwidth by three decades.",1707.05312v3
2004-11-30,Resonating Valence Bond wave function: from lattice models to realistic systems,"Although mean field theories have been very successful to predict a wide
range of properties for solids, the discovery of high temperature
superconductivity in cuprates supported the idea that strongly correlated
materials cannot be qualitatively described by a mean field approach. After the
original proposal by Anderson, there is now a large amount of numerical
evidence that the simple but general resonating valence bond (RVB) wave
function contains just those ingredients missing in uncorrelated theories, so
that the main features of electron correlation can be captured by the
variational RVB approach. Strongly correlated antiferromagnetic (AFM) systems,
like Cs2CuCl4, displaying unconventional features of spin fractionalization,
are also understood within this variational scheme. From the computational
point of view the remarkable feature of this approach is that several
resonating valence bonds can be dealt simultaneously with a single determinant,
at a computational cost growing with the number of electrons similarly to more
conventional methods, such as Hartree-Fock or Density Functional Theory.
Recently several molecules have been studied by using the RVB wave function; we
have always obtained total energies, bonding lengths and binding energies
comparable with more demanding multi configurational methods, and in some cases
much better than single determinantal schemes. Here we present the paradigmatic
case of benzene.",0411745v1
2009-06-15,A Pulsational Mechanism for Producing Keplerian Disks around Be Stars,"Classical Be stars are an enigmatic subclass of rapidly rotating hot stars
characterized by dense equatorial disks of gas that have been inferred to orbit
with Keplerian velocities. Although these disks seem to be ejected from the
star and not accreted, there is substantial observational evidence to show that
the stars rotate more slowly than required for centrifugally driven mass loss.
This paper develops an idea (proposed originally by Hiroyasu Ando and
colleagues) that nonradial stellar pulsations inject enough angular momentum
into the upper atmosphere to spin up a Keplerian disk. The pulsations
themselves are evanescent in the stellar photosphere, but they may be unstable
to the generation of resonant oscillations at the acoustic cutoff frequency. A
detailed theory of the conversion from pulsations to resonant waves does not
yet exist for realistic hot-star atmospheres, so the current models depend on a
parameterized approximation for the efficiency of wave excitation. Once
resonant waves have been formed, however, they grow in amplitude with
increasing height, steepen into shocks, and exert radial and azimuthal Reynolds
stresses on the mean fluid. Using reasonable assumptions for the stellar
parameters, these processes were found to naturally create the inner boundary
conditions required for dense Keplerian disks, even when the underlying B-star
photosphere is rotating as slowly as 60% of its critical rotation speed.
Because there is evidence for long-term changes in Be-star pulsational
properties, this model may also account for the long-term variability of Be
stars, including transitions between normal, Be, and shell phases.",0906.2772v1
2018-07-09,Proposal to Test Quantum Wave-Particle Superposition on Massive Mechanical Resonators,"We present and analyze a proposal for a macroscopic quantum delayed-choice
experiment with massive mechanical resonators. In our approach, the electronic
spin of a single nitrogen-vacancy impurity is employed to control the coherent
coupling between the mechanical modes of two carbon nanotubes. We demonstrate
that a mechanical phonon can be in a coherent superposition of wave and
particle, thus exhibiting both behaviors at the same time. We also discuss the
mechanical noise tolerable in our proposal and predict a critical temperature
below which the morphing between wave and particle states can be effectively
observed in the presence of environment-induced fluctuations. Furthermore, we
describe how to amplify single-phonon excitations of the mechanical-resonator
superposition states to a macroscopic level, via squeezing the mechanical
modes. This approach corresponds to the phase-covariant cloning. Therefore, our
proposal can serve as a test of macroscopic quantum superpositions of massive
objects even with large excitations. This work, which describes a fundamental
test of the limits of quantum mechanics at the macroscopic scale, would have
implications for quantum metrology and quantum information processing.",1807.03194v3
2018-10-21,Nutation dynamics and multifrequency resonance in a many-body seesaw,"The multifrequency resonance has been widely explored in some of the
single-particle models, in which the modulating Rabi model has been most widely
investigated. It has been found that with the diagonal periodic modulation, a
steady dynamics can be realized in some well-defined discrete frequencies.
These frequencies are independent of the off-diagonal couplings. In this work,
we generalize this physics to the many-body seesaw realized using the tilted
Bose-Hubbard model. We find that the wave function will recover to its initial
condition when the modulation frequency is commensurate with the initial energy
level spacing between the ground and the first excited levels. The period is
determined by the driving frequency and commensurate ratio. In this case, the
wave function will almost be restricted to the lowest two instantaneous energy
levels. By projecting the wave function to these two relevant states, the
dynamics is exactly the same as that for the spin precession dynamics and
nutation dynamics around an oscillating axis. We map out the corresponding
phase diagram and show that in the low-frequency regime the state is
thermalized and in the strong modulation limit, the dynamics is determined by
the effective Floquet Hamiltonian. The measurement of these dynamics from the
mean position and mean momentum in phase space are also discussed. Our results
provide a new thought about the multifrequency resonance in the many-body
system.",1810.08898v3
2021-07-06,Ciliary flocking and emergent instabilities enable collective agility in a non-neuromuscular animal,"Effective organismal behavior responds appropriately to changes in the
surrounding environment. Attaining this delicate balance of sensitivity and
stability is a hallmark of the animal kingdom. By studying the locomotory
behavior of a simple animal (\textit{Trichoplax adhaerens}) without muscles or
neurons, here, we demonstrate how monociliated epithelial cells work
collectively to give rise to an agile non-neuromuscular organism. Via direct
visualization of large ciliary arrays, we report the discovery of sub-second
ciliary reorientations under a rotational torque that is mediated by collective
tissue mechanics and the adhesion of cilia to the underlying substrate. In a
toy model, we show a mapping of this system onto an ""active-elastic resonator"".
This framework explains how perturbations propagate information in this array
as linear speed traveling waves in response to mechanical stimulus. Next, we
explore the implications of parametric driving in this active-elastic resonator
and show that such driving can excite mechanical 'spikes'. These spikes in
collective mode amplitudes are consistent with a system driven by parametric
amplification and a saturating nonlinearity. We conduct extensive numerical
experiments to corroborate these findings within a polarized active-elastic
sheet. These results indicate that periodic and stochastic forcing are valuable
for increasing the sensitivity of collective ciliary flocking. We support these
theoretical predictions via direct experimental observation of linear speed
traveling waves which arise from the hybridization of spin and overdamped
density waves. We map how these ciliary flocking dynamics result in agile
motility via coupling between an amplified resonator and a tuning
(Goldstone-like) mode of the system. This sets the stage for how activity and
elasticity can self-organize into behavior which benefits the organism as a
whole.",2107.02934v1
2024-03-16,Coherent Acoustic Control of Defect Orbital States in the Strong-Driving Limit,"We use a bulk acoustic wave resonator to demonstrate coherent control of the
excited orbital states in a diamond nitrogen-vacancy (NV) center at cryogenic
temperature. Coherent quantum control is an essential tool for understanding
and mitigating decoherence. Moreover, characterizing and controlling orbital
states is a central challenge for quantum networking, where optical coherence
is tied to orbital coherence. We study resonant multi-phonon orbital Rabi
oscillations in both the frequency and time domain, extracting the strength of
the orbital-phonon interactions and the coherence of the acoustically driven
orbital states. We reach the strong-driving limit, where the physics is
dominated by the coupling induced by the acoustic waves. We find agreement
between our measurements, quantum master equation simulations, and a
Landau-Zener transition model in the strong-driving limit. Using perturbation
theory, we derive an expression for the orbital Rabi frequency versus acoustic
drive strength that is non-perturbative in the drive strength and agrees well
with our measurements for all acoustic powers. Motivated by continuous wave
spin resonance-based decoherence protection schemes, we model the orbital
decoherence and find good agreement between our model and our measured
few-to-several nanoseconds orbital decoherence times. We discuss the outlook
for orbital decoherence protection.",2403.10989v1
2013-02-26,S wave superconductivity in newly discovered superconductor BaTi$_2$Sb$_2$O revealed by $^{121/123}$Sb-NMR/Nuclear Quadrupole Resonance measurements,"We report the $^{121/123}$Sb-NMR/nuclear quadrupole resonance (NQR)
measurements on the newly-discovered superconductor BaTi$_2$Sb$_2$O with a
two-dimensional Ti$_2$O square-net layer formed with Ti$^{3+}$ (3$d^1$). NQR
measurements revealed that the in-plane four-fold symmetry is broken at the Sb
site below $T_{\rm A} \sim$ 40 K, without an internal field appearing at the Sb
site. These exclude a spin-density wave (SDW)/ charge density wave (CDW)
ordering with incommensurate correlations, but can be understood with the
commensurate CDW ordering at $T_{\rm A}$. The spin-lattice relaxation rate
$1/T_1$, measured at the four-fold symmetry breaking site, decreases below
superconducting (SC) transition temperature $T_{\rm c}$, indicative of the
microscopic coexistence of superconductivity and the CDW/SDW phase below
$T_{\rm A}$. Furthermore, $1/T_1$ of $^{121}$Sb-NQR shows a coherence peak just
below $T_{\rm c}$ and decreases exponentially at low temperatures. These
results are in sharp contrast with those in cuprate and iron-based
superconductors, and strongly suggest that its SC symmetry is classified to an
ordinary s-wave state.",1302.6314v2
2021-09-29,Proton wave function in a water molecule: Breakdown of degeneration caused by interactions with the magnetic field of a Magnetic Resonance Imaging device,"The concept of a Magnetic Resonance Imaging (MRI) device is based on the
emission of radio waves produced by the protons of the hydrogen atoms in water
molecules when placed in a constant magnetic field after they interact with a
pulsed radio frequency (RF) current. When the RF field is turned on, the
protons are brought to a spin excited state. When the RF field is turned off,
the MRI sensors are able to detect the energy released as the protons realign
their spins with the magnetic field. In this work we provide a simple model to
describe the basic physical mechanism responsible for the operation of MRI
devices. We model the water molecule in terms of a central force problem, where
the protons move around the (unstructured) doubly negatively charged oxygen
atom. First, we employ an analytical treatment to obtain the system's wave
function as well as its energy levels, which we show are degenerate. Next, the
energy levels from the water molecule are studied in the presence of a uniform
external magnetic field. As a result, they get shifted and the degeneration is
lifted. We provide numerical results for a magnetic field strength commonly
used in MRI devices.",2109.14531v1
2019-08-19,Resonant excitation of whistler waves by a helical electron beam,"Chorus-like whistler-mode waves that are known to play a fundamental role in
driving radiation-belt dynamics are excited on the Large Plasma Device by the
injection of a helical electron beam into a cold plasma. The mode structure of
the excited whistler wave is identified using a phase-correlation technique
showing that the waves are excited through a combination of Landau resonance,
cyclotron resonance and anomalous cyclotron resonance. The dominant wave mode
excited through cyclotron resonance is quasi-parallel propagating, whereas wave
modes excited through Landau resonance and anomalous cyclotron resonance
propagate at oblique angles that are close to the resonance cone. An analysis
of the linear wave growth rates captures the major observations in the
experiment. The results have important implications for the generation process
of whistler waves in the Earth's inner magnetosphere.",1908.06952v1
2017-12-18,Gravitational wave echoes through new windows,"There has been a striking realization that physics resolving the black hole
information paradox could imply postmerger gravitational wave echoes. We here
report on evidence for echoes from the LIGO compact binary merger events,
GW151226, GW170104, GW170608, GW170814, as well as the neutron star merger
GW170817. There is a signal for each event with a $p$-value of order 1% or
sometimes significantly less. Our study begins with the comparison of echoes
from a variety of horizonless exotic compact objects. Next we investigate the
effects of spin. The identification of the more generic features of echoes then
leads to the development of relatively simple windowing methods, in both time
and frequency space, to extract a signal from noise. The time delay between
echoes is inversely related to the spacing between the spectral resonances, and
it is advantageous to look directly for this resonance structure. We find time
delays for the first four events that are consistent with a simple model that
accounts for mass and spin of the final object, while for the neutron star
merger the final mass and spin are constrained.",1712.06517v4
2021-01-25,"Partial Quantum Coherence, Ultrashort Electron Pulse Statistics, and a Plasmon-Enhanced Nanotip Emitter Based on Metallized Optical Fibers","The present dissertation covers two related research projects. The first
topic was initiated with the ultimate goal of observing quantum degeneracy in
ultrashort free electron pulses. This constitutes a thorough theoretical
analysis of the problem involving partial quantum coherence and spin
polarization of the source in light of a path-integral treatment of the
phenomenon of matter-wave diffraction-in-time. Subsequently, results of a
trailblazing experiment, to be superseded by a Hanbury Brown-Twiss type
conclusive test of free fermion antibunching with electrons, is reported. In
this experiment, the statistical distribution of the emitted electrons is
studied taking advantage of a double-detector coincidence detection technique.
The utilized electron emitters are ultrafast photoemission tungsten nanotip
needle sources which are known to procure large spatial coherence lengths. The
emission statistics is found to be sub-Poissonian. The second project involves
introduction and full characterization of a novel laser-driven electron nanotip
emitter based on metallized fiber optic tapers in which the emission mechanism
is found to be assisted by surface plasmon resonance excitation as predicted
prior to the design of such sources. It is shown that gold-coated fiber optic
nanotips can emit electrons using both low-power continuous wave lasers as well
as femtosecond pulsed lasers tuned to or near the surface plasmon resonance
excitation wavelength of the system. The final chapter entails a proposal of a
spin-polarized electron photoemitter based on the spin Hall effect for which
such a fiber optic nanotip source is exploited.",2101.09953v1
2020-07-09,Magnetic resonance of collective paramagnets with gapped excitations spectrum,"Some magnets due to particular geometry of the exchange bonds do not undergo
transition to the conventional magnetically ordered state despite of the
presence of significant exchange couplings. Instead, a collective paramagnetic
state is formed. The later state can remain stable down to $T=0$ if the ground
state of this magnet turns out to be nonmagnetic singlet separated from the
excited triplet states by an energy gap. Low-temperature spin dynamics of the
collective paramagnets with gapped excitations spectrum (or spin-gap magnets)
can be described in terms of a dilute gas of the triplet excitations. Applied
magnetic field can suppress the energy gap, resulting in the formation of the
gapless spin-liquid state or even leading to the unusual phenomenon of
field-induced antiferromagnetic order. Introduction of defects in the
crystallographic structure of the spin-gap magnet can result either in the
formation of multi-spin paramagnetic center or in the formation of randomly
distributed modified exchange bonds in the crystal. This review includes
results of electron spin resonance (ESR) spectroscopy study of several
representative quantum paramagnets with gapped excitations spectrum:
quasy-two-dimensional magnet \phcc{}, quasy-one-dimensional magnets of
""spin-tube"" type \sul{} and ""spin-ladder"" type \dimpy{}. We will demonstrate
that ESR absorption spectra reveal common features of these systems: ESR
spectroscopy allows to observe and characterize fine structure if the triplet
energy levels, to identify many-particles relaxation processes in the gas of
triplet excitations and to observe collective spin-wave oscillations in the
field induced antiferromagnetically ordered state, as well as to observe some
individual features of the studied systems.",2007.04885v1
2018-03-05,Manifolds of magnetic ordered states and excitations in the almost Heisenberg pyrochlore antiferromagnet MgCr2O4,"In spinels ACr2O4 (A=Mg, Zn) realisation of the classical pyrochlore
Heisenberg antiferromagnet model is complicated by a strong spin-lattice
coupling: the extensive degeneracy of the ground state is lifted by a
magneto-structural transition at TN=12.5 K. We study the resulting
low-temperature low-symmetry crystal structure by synchrotron x-ray
diffraction. The consistent features of x-ray low-temperature patterns are
explained by the tetragonal model of Ehrenberg et. al (Pow. Diff. 17, 230(
2002)), while other features depend on sample or cooling protocol. Complex
partially ordered magnetic state is studied by neutron diffraction and
spherical neutron polarimetry. Multiple magnetic domains of configuration arms
of the propagation vectors k1=(1/2 1/2 0), k2=(1 0 1/2) appear. The ordered
moment reaches 1.94(3) muB/Cr3+ for k1 and 2.08(3) muB/Cr3+ for k2, if equal
amount of the k1 and k2 phases is assumed. The magnetic arrangements have the
dominant components along the [110] and [1-10] diagonals and a smaller
c-component. By inelastic neutron scattering we investigate the spin
excitations, which comprise a mixture of dispersive spin waves propagating from
the magnetic Bragg peaks and resonance modes centered at equal energy steps of
4.5 meV. We interpret these as acoustic and optical spin wave branches, but
show that the neutron scattering cross sections of transitions within a unit of
two corner-sharing tetrahedra match the observed intensity distribution of the
resonances. The distinctive fingerprint of cluster-like excitations in the
optical spin wave branches suggests that propagating excitations are localized
by the complex crystal structure and magnetic orders.",1803.01703v1
2021-11-19,On the applicability of single-spacecraft interferometry methods using electric field probes,"When analyzing plasma waves, a key parameter to determine is the phase
velocity. It enables us to, for example, compute wavelengths, wave potentials,
and determine the energy of resonant particles. The phase velocity of a wave,
observed by a single spacecraft equipped with electric field probes, can be
determined using interferometry techniques. While several methods have been
developed to do this, they have not been documented in detail. In this study,
we use an analytical model to analyze and compare three interferometry methods
applied on the probe geometry of the Magnetospheric Multiscale spacecraft. One
method relies on measured probe potentials, whereas the other two use different
E-field measurements: one by reconstructing the E-field between two probes and
the spacecraft, the other by constructing four pairwise parallel E-field
components in the spacecraft spin-plane. We find that the potential method is
sensitive both to how planar the wave is, and to spacecraft potential changes
due to the wave. The E-field methods are less affected by the spacecraft
potential, and while the reconstructed E-field method is applicable in some
cases, the second E-field method is almost always preferable. We conclude that
the potential based interferometry method is useful when spacecraft potential
effects are negligible and the signals of the different probes are very well
correlated. The method using two pairs of parallel E-fields is practically
always preferable to the reconstructed E-field method and produces the correct
velocity in the spin-plane, but it requires knowledge of the propagation
direction to provide the full velocity.",2111.10288v2
1998-01-16,Spin observables for the pd <-> pi+ t process around the Delta resonance,"The proton analyzing power Ay0 and the deuteron tensor analyzing power T20
are evaluated for the pd <-> pi+ t process, in the energy region around and
above the Delta resonance. These calculations extend a previous analysis of the
excitation function and differential cross-section, based on a model embodying
one-- and two-body p-wave absorption mechanisms and isobar excitation. The
three-nucleon bound state and the pd scattering state are evaluated through
Faddeev techniques for both the Bonn and Paris potentials. The spin variables
exhibit a greater sensitivity to the number of included three-nucleon partial
waves than the cross-sections, while the role played by the initial-- or
final-state interactions appears to be small. The results for the tensor
analyzing power at backward angles show a non-negligible dependence on the
potentials employed, consistently with what has been previously found for the
cross-sections. The calculation of spin observables gives a clear indication
that other reaction mechanisms (presumably s-wave two-body absorption) have to
be included in the model, in order to reproduce the experimental data below the
Delta-resonance, in analogy with the simpler pp <-> pi+ d process.",9801027v1
2013-10-30,Instability windows and evolution of rapidly rotating neutron stars,"We consider an instability of rapidly rotating neutron stars in low-mass
X-ray binaries (LMXBs) with respect to excitation of r-modes (which are
analogous to Earth's Rossby waves controlled by the Coriolis force). We argue
that finite temperature effects in the superfluid core of a neutron star lead
to a resonance coupling and enhanced damping (and hence stability) of
oscillation modes at certain stellar temperatures. Using a simple
phenomenological model we demonstrate that neutron stars with high spin
frequency may spend a substantial amount of time at these `resonance'
temperatures. This finding allows us to explain puzzling observations of hot
rapidly rotating neutron stars in LMXBs and to predict a new class of hot,
non-accreting, rapidly rotating neutron stars, some of which may have already
been observed and tentatively identified as quiescent LMXB (qLMXB) candidates.
We also impose a new theoretical limit on the neutron star spin frequency,
explaining the cut-off spin frequency ~730 Hz, following from the statistical
analysis of accreting millisecond X-ray pulsars. Besides explaining the
observations, our model provides a new tool to constrain superdense matter
properties comparing measured and theoretically predicted resonance
temperatures.",1310.8103v2
2014-06-07,Dynamically generated resonances from the vector meson-octet baryon interaction in the strangeness zero sector,"The interaction potentials between vector mesons and octet baryons are
calculated explicitly with a summation of t-, s-, u-channel diagrams and a
contact term originating from the tensor interaction. Many resonances are
generated dynamically in different channels of strangeness zero by solving the
coupled-channel Lippman-Schwinger equations with the method of partial wave
analysis, and their total angular momenta are determined. The spin partners
N(1650)1/2^{-} and N(1700)3/2^-, N(1895)1/2^{-} and N(1875)3/2^-, and the state
N(2120)3/2^- are all produced respectively in the isospin I=1/2 sector. In the
isospin I=3/2 sector, the spin partners Delta(1620)1/2^- and Delta(1700)3/2^-
are also associated with the pole in the complex energy plane. According to the
calculation results, a J^P=1/2^- state around 2000 MeV is predicted as the spin
partner of N(2120)3/2^-. Some resonances are well fitted with their
counterparts listed in the newest review of Particle Data Group(PDG), while
others might stimulate the experimental observation in these energy regions in
the future.",1406.1841v2
2018-10-29,Manipulating spin wave polarization in synthetic antiferromagnet,"Polarization is a key ingredient of all waves, including the electromagnetic
wave, the acoustic wave, as well as the spin wave. Due to the fixed
ferromagnetic order, the spin wave in ferromagnet is limited to the right
circular polarization. The spin wave in antiferromagnet, however, is endowed
with the full polarization degree of freedom because of the two identical
magnetic sublattices. In the synthetic antiferromagnet, the two magnetic
sublattices are spatially separated into two sublayers. The circular
polarization of spin wave is partially locked to the magnetic sublattice of the
antiferromagnet, thus to the sublayer in synthetic antiferromagnet. Based on
this unique polarization-sublayer locking mechanism, we show that both the
circular spin wave polarizer and retarder (wave-plate) can be straightforwardly
realized using synthetic antiferromagnets by restructuring the sublayers, e.g.
by removing or capping a portion of a sublayer. Manipulating spin wave
polarization by geometrical engineering provides a simple yet powerful paradigm
in harnessing the spin wave polarization for spin information processing.",1810.12149v1
2021-06-04,Imaging spin-wave damping underneath metals using electron spins in diamond,"Spin waves in magnetic insulators are low-damping signal carriers that could
enable a new generation of spintronic devices. The excitation, control, and
detection of spin waves by metal electrodes is crucial for interfacing these
devices to electrical circuits. It is therefore important to understand
metal-induced damping of spin-wave transport, but characterizing this process
requires access to the underlying magnetic films. Here we show that spins in
diamond enable imaging of spin waves that propagate underneath metals in
magnetic insulators, and then use this capability to reveal a 100-fold increase
in spin-wave damping. By analyzing spin-wave-induced currents in the metal, we
derive an effective damping parameter that matches these observations well. We
furthermore detect buried scattering centers, highlighting the technique's
power for assessing spintronic device quality. Our results open new avenues for
studying metal - spin-wave interaction and provide access to interfacial
processes such as spin-wave injection via the spin-Hall effect.",2106.02508v2
2022-03-16,Nuclear Magnetic Resonance for Arbitrary Spin Values in the Rotating Wave Approximation,"In order to probe the transitions of a nuclear spin $s$ from one of its
substate quantum numbers $m$ to another substate $m'$, the experimenter applies
a magnetic field ${\bm B}_0$ in some particular direction, such along $\hat{\bm
z}$, and then applies an weaker field ${\bm B}_1(t)$ that is oscillatory in
time with the angular frequency $\omega$, and is normally perpendicular to
${\bm B}_0$, such as ${\bm B}_1(t)=B_1\hat{\bm x}\cos(\omega t)$. In the
rotating wave approximation, ${\bm B}_1(t)=B_1[\hat{\bm x}\cos(\omega
t)+\hat{\bm y}\sin(\omega t)]$. Although this problem is solved for spin
$\frac{1}{2}$ in every quantum mechanics textbook, for the general spin $s$
case, its general solution has been published only for the overall probability
of a transition between the states, but the time dependence of the probability
of finding the nucleus in each of the substates has not previously been
published. Here we present an elementary method to solve this problem exactly,
and present figures for the time dependencies of the various substates states
for a variety of initial substate probabilities for a variety of $s$ values. We
found a new result: unlike the $s=\frac{1}{2}$ case, for which if the initial
probability of finding the particle in one of the substates was 1, and the time
dependence of the probabilities of each of the substates oscillates between 0
and 1, for higher spin values, the time dependencies of the probabilities
finding the particle in each of its substates, which periodic, is considerably
more complicated.",2203.08755v1
2023-04-10,Efficient multi-timescale dynamics of precessing black-hole binaries,"We present analytical and numerical progress on black-hole binary spin
precession at second post-Newtonian order using multi-timescale methods. In
addition to the commonly used effective spin which acts as a constant of
motion, we exploit the weighted spin difference and show that such
reparametrization cures the coordinate singularity that affected the previous
formulation for the case of equal-mass binaries. The dynamics on the precession
timescale is written down in closed form in both coprecessing and inertial
frames. Radiation reaction can then be introduced in a quasi-adiabatic fashion
such that, at least for binaries on quasi-circular orbits, gravitational
inspirals reduce to solving a single ordinary differential equation. We provide
a broad review of the resulting phenomenology and rewrite the relevant physics
in terms of the newly adopted parametrization. This includes the spin-orbit
resonances, the up-down instability, spin propagation at past time infinity,
and new precession estimators to be used in gravitational-wave astronomy. Our
findings are implemented in version 2 of the public Python module PRECESSION.
Performing a precession-averaged post-Newtonian evolution from/to arbitrarily
large separation takes $\lesssim 0.1$ s on a single off-the-shelf processor - a
50x speedup compared to our previous implementation. This allows for a wide
variety of applications including propagating gravitational-wave posterior
samples as well as population-synthesis predictions of astrophysical nature.",2304.04801v2
2013-08-08,Imprints of spin-orbit density wave in the hidden order state of URu2Si2,"The mysterious second order quantum phase transition, commonly attributed to
the `hidden-order' (HO) state, in heavy-fermion metal URu2Si2 exhibits a number
of paradoxical electronic and magnetic properties which cannot be associated
with any conventional order parameter. We characterize and reconcile these
exotic properties of the HO state based on a spin-orbit density wave order
(SODW), constructed on the basis of a realistic density-functional theory (DFT)
band structure. We quantify the nature of the gapped electronic and magnetic
excitation spectrum, in agreement with measurements, while the magnetic moment
is calculated to be zero owing to the spin-orbit coupling induced time-reversal
invariance. Furthermore, a new collective mode in the spin-1 excitation
spectrum is predicted to localize at zero momentum transfer in the HO state
which can be visualized, for example, by electron spin resonance (ESR) at zero
magnetic field or polarized inelastic neutron scattering measurements. The
results demonstrate that the concomitant broken and invariant symmetries
protected SODW order not only provides insights into numerous nontrivial
hidden-order phenomena, but also offers a parallel laboratory to the formation
of a topologically protected quantum state beyond the quantum spin-Hall state
and Weyl semimetals.",1308.1992v2
2021-03-10,Spin effects on neutron star fundamental-mode dynamical tides: phenomenology and comparison to numerical simulations,"Gravitational waves from neutron star binary inspirals contain information on
strongly-interacting matter in unexplored, extreme regimes. Extracting this
requires robust theoretical models of the signatures of matter in the
gravitational-wave signals due to spin and tidal effects. In fact, spins can
have a significant impact on the tidal excitation of the quasi-normal modes of
a neutron star, which is not included in current state-of-the-art waveform
models. We develop a simple approximate description that accounts for the
Coriolis effect of spin on the tidal excitation of the neutron star's
quadrupolar and octupolar fundamental quasi-normal modes and incorporate it in
the SEOBNRv4T waveform model. We show that the Coriolis effect introduces only
one new interaction term in an effective action in the co-rotating frame of the
star, and fix the coefficient by considering the spin-induced shift in the
resonance frequencies that has been computed numerically for the mode
frequencies of rotating neutron stars in the literature. We investigate the
impact of relativistic corrections due to the gravitational redshift and
frame-dragging effects, and identify important directions where more detailed
theoretical developments are needed in the future. Comparisons of our new model
to numerical relativity simulations of double neutron star and neutron
star-black hole binaries show improved consistency in the agreement compared to
current models used in data analysis",2103.06100v2
2014-08-05,Electrically driven spin resonance in a bent disordered carbon nanotube,"Resonant manipulation of carbon nanotube valley-spin qubits by an electric
field is investigated theoretically. We develop a new analysis of electrically
driven spin resonance exploiting fixed physical characteristics of the
nanotube: a bend and inhomogeneous disorder. The spectrum is simulated for an
electron valley-spin qubit coupled to a hole valley-spin qubit and an impurity
electron spin, and features that coincide with a recent measurement are
identified. We show that the same mechanism allows resonant control of the full
four-dimensional spin-valley space.",1408.0951v1
2015-01-31,"An atomic resolution, single-spin magnetic resonance detection concept based on tunneling force microscopy","A comprehensive study of a force detected single-spin magnetic resonance
measurement concept with atomic spatial resolution is presented. The method is
based upon electrostatic force detection of spin-selection rule controlled
single-electron tunneling between two electrically isolated paramagnetic
states. Single spin magnetic resonance detection is possible by measuring the
force detected tunneling charge noise on and off spin resonance. Simulation
results of this charge noise, based upon physical models of the tunneling and
spin physics, are directly compared to measured AFM system noise. The results
show that the approach could provide single spin measurement of electrically
isolated qubit states with atomic spatial resolution at room temperature.",1502.00053v1
2008-04-11,Dirac neutrino magnetic moment and the shock wave revival in a supernova explosion,"The process of the two-step conversion of the neutrino helicity, $\nu_L \to
\nu_R \to \nu_L$, is analysed in the supernova conditions, where the first
stage is realized due to the interaction of the neutrino magnetic moment with
the plasma electrons and protons in the supernova core. The second stage is
caused by the neutrino resonant spin-flip in a magnetic field of the supernova
envelope. Given the neutrino magnetic moment within the interval $10^{-13}
\mu_{\rm B} < \mu_\nu < 10^{-12} \mu_{\rm B}$, and with the existence of the
magnetic field at the scale $\sim 10^{13}$ G between the neutrinosphere and the
shock-wave stagnation region, it is shown that an additional energy of the
order of $10^{51}$ erg can be injected into this region during the typical time
of the shock-wave stagnation. This energy could be sufficient for stumulation
of the damped shock wave.",0804.1916v2
2021-07-22,The ${\bar K}N$ interaction in higher partial waves,"We present a chiral ${\bar K}N$ interaction model that has been developed and
optimized in order to account for the experimental data of inelastic ${\bar
K}N$ reaction channels that open at higher energies. In particular, we study
the effect of the higher partial waves which originate directly from the chiral
Lagrangian, as they could supersede the role of high-spin resonances employed
in earlier phenomenological models to describe meson-baryon cross sections in
the 2~GeV region. We present a detailed derivation of the partial wave
amplitudes that emerge from the chiral SU(3) meson-baryon Lagrangian up to the
d-waves and next-to-leading order in the chiral expansion. We implement a
nonperturbative unitarization in coupled channels and optimize the model
parameters to a large pool of experimental data in the relevant energy range
where these new contributions are expected to be important. The obtained
results are encouraging. They indicate the ability of the chiral higher partial
waves to extend the description of the scattering data to higher energies and
to account for structures in the reaction cross sections that cannot be
accommodated by theoretical models limited to the s-waves.",2107.10560v1
2018-05-30,Magnonic band gap and mode hybridization in continuous Permalloy film induced by vertical coupling with an array of Permalloy ellipses,"We investigate magnonic band structure in thin homogeneous permalloy film
decorated with periodic array of elliptically shaped permalloy dots and
separated by non-magnetic Pt spacer. We demonstrated experimentally formation
of the magnonic band structure for Damon-Eshbach wave propagating in permalloy
film with the band gap opened at the Brillouin zone border and band splitting
at smaller wavenumbers, due to the Bragg interference and interaction of
propagating wave of the continuous film with a standing resonant mode of the
nano-ellipses, respectively. The shape anisotropy of the permalloy nanodots
allows to control the spin wave dynamics through the switch between two states
of the magnetization with respect to the underneath film magnetization, thus
enabling magnonic band structure reprogrammability. With numerical analysis we
show, that predominant role in formation of the magnonic band structure is
played by a vertical dynamic coupling between propagating wave in the film and
magnetization oscillations in the nanodots.",1805.12178v2
2023-05-05,Breaking the entangling gate speed limit for trapped-ion qubits using a phase-stable standing wave,"All laser-driven entangling operations for trapped-ion qubits have hitherto
been performed without control of the optical phase of the light field, which
precludes independent tuning of the carrier and motional coupling. By placing
$^{88}$Sr$^+$ ions in a $\lambda=674$ nm standing wave, whose relative position
is controlled to $\approx\lambda/100$, we suppress the carrier coupling by a
factor of $18$, while coherently enhancing the spin-motion coupling. We
experimentally demonstrate that the off-resonant carrier coupling imposes a
speed limit for conventional traveling-wave M{\o}lmer-S{\o}rensen gates; we use
the standing wave to surpass this limit and achieve a gate duration of $15\
\mu$s, restricted by the available laser power.",2305.03450v2
2007-05-30,"Resonant spin polarization in a two-dimensional hole gas: Effect of the Luttinger term, structural inversion asymmetry and Zeeman splitting","The electric-field-induced resonant spin polarization of a two-dimensional
hole gas described by Luttinger Hamiltonian with structural inversion asymmetry
and Zeeman splitting in a perpendicular magnetic field was studied. The spin
polarization arising from splitting between the light and the heavy hole bands
shows a resonant peak at a certain magnetic field. Especially, the competition
between the Luttinger term and the structural inversion asymmetry leads to a
rich resonant peaks structure, and the required magnetic field for the
resonance may be effectively reduced by enlarging the effective width of the
quantum well. Furthermore, the Zeeman splitting tends to move the resonant spin
polarization to a relative high magnetic field and destroy these rich resonant
spin phenomena. Finally, both the height and the weight of the resonant peak
increase as the temperature decreases. It is believed that such resonant spin
phenomena can be verified in the sample of a two-dimensional hole gas, and it
may provide an efficient way to control spin polarization by an external
electric field.",0705.4355v2
2016-08-17,Electron Spin Resonance at the Level of 10000 Spins Using Low Impedance Superconducting Resonators,"We report on electron spin resonance (ESR) measurements of phosphorus donors
localized in a 200 square micron area below the inductive wire of a lumped
element superconducting resonator. By combining quantum limited parametric
amplification with a low impedance microwave resonator design we are able to
detect around 20000 spins with a signal-to-noise ratio (SNR) of 1 in a single
shot. The 150 Hz coupling strength between the resonator field and individual
spins is significantly larger than the 1 - 10 Hz coupling rates obtained with
typical coplanar waveguide resonator designs. Due to the larger coupling rate,
we find that spin relaxation is dominated by radiative decay into the resonator
and dependent upon the spin-resonator detuning, as predicted by Purcell.",1608.05130v2
2019-11-29,Omni-resonant space-time wave packets,"We describe theoretically and verify experimentally a novel class of
diffraction-free pulsed optical beams that are `Omni-resonant': they have the
remarkable property of transmission through planar Fabry-Perot resonators
without spectral filtering even if their bandwidth far exceeds the cavity
resonant linewidth. Ultrashort wave packets endowed with a specific
Spatio-temporal structure couple to a \textit{single} resonant mode
independently of its linewidth. We confirm that such `space-time' Omni-resonant
wave packets retain their bandwidth (1.6~nm), Spatio-temporal profile (1.3-ps
pulse width, 4-$\mu$m beam width), and diffraction-free behavior upon
transmission through cavities with resonant linewidths of 0.3-nm and 0.15-nm.",1912.00092v1
2022-12-04,Superradiant Masing with Solid-state Spins at Room Temperature,"Steady-state superradiance and superradiant lasing attract significant
attentions in the field of optical lattice clocks, but have not been achieved
so far due to the technical challenges and atom loss problem. In this article,
we propose that their counter-part may be observed in the microwave domain with
solid-state spins-microwave resonator systems at room temperature with
realistic technical restrictions. To validate our proposal, we investigate
systematically the system dynamics and steady-state by solving quantum master
equations for the multi-level and multi-process dynamic of trillions of spins.
To this end, we employ a mean-field approach, and convert the mean-field
dynamics of the spin ensemble into the one in a more intuitive Dicke state
picture. Our calculations show that for systems with nitrogen vacancy center
spins and pentacene molecular spins the superradiant Rabi oscillations occur
firstly due to transitions among different Dicke states, and the subsequent
continuous-wave superradiant masing can achieve a linewidth well below
millihertz. Our work may guide further exploration of transient and
steady-state superradiant masing with the mentioned and other solid-state spins
systems, such as silicon vacancy centers in silicon carbide and boron vacancy
centers in hexagonal boron nitride, where the coherent radiation with
ultra-narrow linewidth may find applications in deep-space communications,
radio astronomy and high-precision metrology.",2212.01864v1
2012-07-31,Spin excitations in a single La$_2$CuO$_4$ layer,"The dynamics of S=1/2 quantum spins on a 2D square lattice lie at the heart
of the mystery of the cuprates
\cite{Hayden2004,Vignolle2007,Li2010,LeTacon2011,Coldea2001,Headings2010,Braicovich2010}.
In bulk cuprates such as \LCO{}, the presence of a weak interlayer coupling
stabilizes 3D N\'{e}el order up to high temperatures. In a truly 2D system
however, thermal spin fluctuations melt long range order at any finite
temperature \cite{Mermin1966}. Further, quantum spin fluctuations transfer
magnetic spectral weight out of a well-defined magnon excitation into a
magnetic continuum, the nature of which remains controversial
\cite{Sandvik2001,Ho2001,Christensen2007,Headings2010}. Here, we measure the
spin response of \emph{isolated one-unit-cell thick layers} of \LCO{}. We show
that coherent magnons persist even in a single layer of \LCO{} despite the loss
of magnetic order, with no evidence for resonating valence bond (RVB)-like spin
correlations \cite{Anderson1987,Hsu1990,Christensen2007}. Thus these
excitations are well described by linear spin wave theory (LSWT). We also
observe a high-energy magnetic continuum in the isotropic magnetic response.
This high-energy continuum is not well described by 2 magnon LSWT, or indeed
any existing theories.",1208.0018v1
2018-03-30,Dynamical DMRG study of spin and charge excitations in the four-leg t-t'-J ladder,"The ground state of the t-t'-J ladder with four legs favors a striped charge
distribution for the parameters corresponding to hole-doped cuprate
superconductors. We investigate the dynamical spin and charge structure factors
of the model by using the dynamical density matrix renormalization group (DMRG)
and clarify the influence of the stripe on the structure factors. The dynamical
charge structure factor along the momentum direction from q=(0,0) to (pi,0)
clearly shows low-energy excitations corresponding to the stripe order in hole
doping. On the other hand, the stripe order weakens in electron doping,
resulting in fewer low-energy excitations in the charge channel. In the spin
channel, we find incommensurate spin excitations near q=(pi,pi) forming an
hourglass behavior in hole doping, while in electron doping we find clearly
spin-wave-like dispersions starting from q=(pi,pi). Along the (0,0)-(pi,0)
direction, the spin excitations are strongly influenced by the stripes in hole
doping, resulting in two branches that form a discontinuous behavior in the
dispersion. In contrast, the electron-doped systems show a downward shift in
energy toward (pi,0). These behaviors along the (0,0)-(pi,0) direction are
qualitatively similar to momentum-dependent spin excitations recently observed
by resonant inelastic x-ray scattering experiments in hole- and electron-doped
cuprate superconductors.",1803.11342v2
2020-06-30,Spin and density self-ordering in dynamic polarization gradients fields,"We study the zero-temperature quantum phase diagram for a two-component
Bose-Einstein condensate in an optical cavity. The two atomic spin states are
Raman coupled by two transverse orthogonally-polarized, blue detuned plane-wave
lasers inducing a repulsive cavity potential. For weak pump the lasers favor a
state with homogeneous density and predefined uniform spin direction. When one
pump laser is polarized parallel to the cavity mode polarization, the photons
coherently scattered into the resonator induce a polarization gradient along
the cavity axis, which mediates long-range density-density, spin-density, and
spin-spin interactions. We show that the coupled atom-cavity system implements
central aspects of the $t$-$J$-$V$-$W$ model with a rich phase diagram. At the
mean-field limit we identify at least four qualitatively distinct density- and
spin-ordered phases including ferro- and anti-ferromagnetic order along the
cavity axis, which can be controlled via the pump strength and detuning. A real
time observation of amplitude and phase of the emitted fields bears strong
signatures of the realized phase and allows for real-time determination of
phase transition lines. Together with measurements of the population imbalance
most properties of the phase diagram can be reconstructed.",2006.16582v2
2013-05-24,Realizing a lattice spin model with polar molecules,"With the recent production of polar molecules in the quantum regime,
long-range dipolar interactions are expected to facilitate the understanding of
strongly interacting many-body quantum systems and to realize lattice spin
models for exploring quantum magnetism. In atomic systems, where interactions
require wave function overlap, effective spin interactions on a lattice can be
realized via superexchange; however, the coupling is weak and limited to
nearest-neighbor interactions. In contrast, dipolar interactions exist in the
absence of tunneling and extend beyond nearest neighbors. This allows coherent
spin dynamics to persist even at high entropy and low lattice filling. Effects
of dipolar interactions in ultracold molecular gases have so far been limited
to the modification of chemical reactions. We now report the observation of
dipolar interactions of polar molecules pinned in a 3D optical lattice. We
realize a lattice spin model with spin encoded in rotational states, prepared
and probed by microwaves. This spin-exchange interaction arises from the
resonant exchange of rotational angular momentum between two molecules. We
observe clear oscillations in the evolution of the spin coherence in addition
to an overall decay. The frequency of these oscillations, the strong dependence
of the spin coherence time on the lattice filling, and the effect of a
multi-pulse sequence designed to reverse dynamics due to two-body exchange
interactions all provide evidence of dipolar interactions. We also demonstrate
suppression of loss in weak lattices due to a quantum Zeno mechanism.
Measurements of these tunneling-induced losses allow us to independently
determine the lattice filling factor. These results comprise an initial
exploration of the behavior of many-body spin models with direct, long-range
spin interactions and lay the groundwork for future studies of many-body
dynamics in spin lattices.",1305.5598v1
2003-12-03,Magnetostatic Spin Waves,"In general, Maxwell's equations require that a wave of magnetic field be
accompanied by a wave of electric field, and vice versa. In magnetic media it
is possible to have waves of magnetization with negligible electric field. We
discuss an example of this based on ferromagnetic spin waves.",0312026v1
2013-07-31,Discrete exact and quasi-resonances of Rossby/drift waves on $\b$-plane with periodic boundary conditions,"Analysis of resonance clustering in weakly nonlinear dispersive wave systems,
also called discrete wave turbulent systems, is a new methodology successfully
used in the last years for characterizing energy transport due to exact and
quasi-resonances. Quite recently this methodology has been used in the paper by
M. D. Bustamante, U. Hayat ""Complete classification of discrete resonant
Rossby/drift wave triads on periodic domains"", \cite{BH13}, in order to show
that resonance clustering is very sparse and quasi-resonances (that is,
resonances with small enough detuning) play major role in the energy transport
in this specific wave system. On the other hand, in the paper by M. Yamada, T.
Yoneda ""Resonant interaction of Rossby waves in two-dimensional flow on
$\beta$-plane"", \cite{YaYo13}, the same physical system is studied and a
mathematically rigorous theorem is proven: at high $\b$, the flow dynamics is
governed exclusively by resonant interactions. In our present paper we
demonstrate that this seeming contradiction between numerical results
\cite{BH13} and analytical results \cite{YaYo13} are due to some pitfalls in
numerical studies of exact and quasi-resonances presented in \cite{BH13}. We
also demonstrate that resonance clustering of drift waves on periodic
$\b$-plane differs substantially from characteristic resonance clustering in
other 3-wave systems: instead of a usual set of isolated triads and a few
bigger clusters, there exists \emph{no isolated triads} in this case. Resonant
triads are interconnected in a complicated way and the smallest cluster
consists of 6 connected triads.",1307.8272v1
1997-10-08,Spin susceptibility and the pi-excitation in underdoped cuprates,"The dynamical spin susceptibility chi'' at wave vector (pi, pi) and the
spectrum pi'' of the spin-triplet particle--particle excitation with center of
mass momentum (pi, pi) (pi-excitation) are considered in the slave-boson
formulation of the t--J-model. Propagators are calculated in a diagrammatic
t-matrix approximation in the d-wave superconducting state for a wide doping
range. The resulting spectra chi'' and pi'' both show a resonance at a doping
dependent energy, in qualitative agreement with recent numerical cluster
calculations. In underdoped systems, the peak position is comparable to that
found in neutron scattering experiments. The peak in chi'' as well as pi'' is
at low doping entirely caused by spin fluctuations, whereas the triplet
particle--particle channel does not contribute as a collective mode.",9710065v1
2000-12-22,The magnetic ordering in the mixed valence compound beta-Na0.33V2O5,"The low-temperature electron spin resonance (ESR) spectra and the static
magnetization data obtained for the stoichiometric single crystals of
$\beta$-Na$_{0.33}$V$_2$O$_5$ indicate that this quasi-one-dimensional mixed
valence (V4+/V5+) compound demonstrates at $T_N=22$ K the phase transition into
the canted antiferromagnetically ordered state. The spontaneous magnetization
of $3.4\times 10^{-3}$ $\mu_B$ per V$^{4+}$ ion was found to be oriented along
the two-fold $b$ axis of the monoclinic structure, the vector of
antiferromagnetism is aligned with the $a$ axis and the Dzyaloshinsky vector is
parallel to the $c$-axis. The experimental data were successfully described in
the frame of the macroscopic spin dynamics and the following values for the
macroscopic parameters of the spin system were obtained: the Dzyaloshinsky
field $H_D=6$ kOe, the energy gaps of two branches of the spin wave spectrum
$\Delta_1=48$ GHz and $\Delta_2=24$ GHz.",0012434v1
2004-08-06,Ultrafast initialization and QND-readout of a spin qubit via control of nanodot-vacuum coupling,"Ultrafast initialization enables fault-tolerant processing of quantum
information while QND readout enables scalable quantum computation. By
spatially assembling photon resonators and wave-guides around an n-doped
nanodot and by temporally designing optical pump pulses, an efficient quantum
pathway can be established from an electron spin to a charged exciton to a
cavity photon and finally to a flying photon in the waveguide. Such control of
vacuum-nanodot coupling can be exploited for ultrafast initialization and QND
readout of the spin, which are particularly compatible with the optically
driven spin quantum computers.",0408148v2
2004-10-07,Quantum Fluctuations and Excitations in Antiferromagnetic Quasicrystals,"We study the effects of quantum fluctuations and the excitation spectrum for
the antiferromagnetic Heisenberg model on a two-dimensional quasicrystal, by
numerically solving linear spin-wave theory on finite approximants of the
octagonal tiling. Previous quantum Monte Carlo results for the distribution of
local staggered magnetic moments and the static spin structure factor are
reproduced well within this approximate scheme. Furthermore, the magnetic
excitation spectrum consists of magnon-like low-energy modes, as well as
dispersionless high-energy states of multifractal nature. The dynamical spin
structure factor, accessible to inelastic neutron scattering, exhibits
linear-soft modes at low energies, self-similar structures with bifurcations
emerging at intermediate energies, and flat bands in high-energy regions. We
find that the distribution of local staggered moments stemming from the
inhomogeneity of the quasiperiodic structure leads to a characteristic energy
spread in the local dynamical spin susceptibility, implying distinct nuclear
magnetic resonance spectra, specific for different local environments.",0410180v1
2007-05-31,X-ray Microdiffraction Images of Antiferromagnetic Domain Evolution in Chromium,"Magnetic x-ray diffraction combined with x-ray focusing optics is used to
image individual antiferromagnetic spin density wave domains in a chromium
single crystal at the micron scale. The cross section for non-resonant magnetic
x-ray scattering depends on the antiferromagnetic modulation vector and spin
polarization direction and allows these quantities to be extracted
independently. The technique is used to show that the broadening of the
nominally first order ""spin-flip"" transition at 123 K, at which the spins
rotate by 90 deg., originates at the walls between domains with orthogonal
modulation vectors. During cooling the transition begins at these walls and
progresses inwards. The modulation-vector domains are themselves unchanged.",0705.4636v1
2008-05-28,Dynamic nuclear polarization with simultaneous excitation of electronic and nuclear transitions,"Dynamic nuclear polarization transfers spin polarization from electrons to
nuclei. We have achieved this by a new method, simultaneously exciting
transitions of electronic and nuclear spins. The efficiency of this technique
improves with increasing magnetic field. Experimental results are shown for
N@C60 with continuous-wave microwaves, which can be expected to produce even
higher polarization than the corresponding pulsed techniques for electron spins
greater than 1/2. The degree of nuclear polarization in this case can be easily
monitored through the intensities of the well resolved hyperfine components in
the EPR spectrum. The nuclear spin-lattice relaxation time is orders of
magnitude longer than that of the electrons.",0805.4357v1
2009-12-21,Dispersive Spin Fluctuations in the near optimally-doped superconductor Ba(Fe1-xCox)2As2 ($x$=0.065),"Inelastic neutron scattering is used to probe the collective spin excitations
of the near optimally-doped superconductor Ba(Fe1-xCox)2As2 ($x$=0.065).
Previous measurements on the antiferromagnetically ordered parents of this
material show a strongly anisotropic spin-wave velocity. Here we measure the
magnetic excitations up to 80 meV and show that a similar anisotropy persists
for superconducting compositions. The dispersive mode measured here connects
directly with the spin resonance previously observed in this compound. When
placed on an absolute scale, our measurements show that the local- or
wavevector- integrated susceptibility is larger in magnitude than that of the
ordered parents over the energy range probed.",0912.4134v3
2010-07-05,Itinerant-Electron Magnetism in the Heisenberg Limit,"The Hubbard model in the Heisenberg limit is studied by Kondo-lattice theory.
The Kondo temperature T_K or k_BT_K, which is an energy scale of low-energy
local quantum spin fluctuations, is enhanced by the resonating valence bond
(RVB) mechanism, so that T_K\simeq T_MF/(2D), where T_MF is the Neel
temperature in the mean-field approximation of the corresponding Heisenberg
model and D is the spatial dimensionality. Electrons certainly behave as
localized spins at T\gg T_K, but they are still itinerant at T\ll T_K unless an
antiferromagnetic complete gap opens. When the Neel temperature T_N is so high
that T_N\gg T_MF/(2D), magnetism is prototypic local-moment magnetism. When T_N
is so low that T_N \ll T_MF/(2D) because of low dimensionality or frustration,
magnetism is itinerant-electron magnetism of an almost spin liquid, i.e., a
normal Fermi liquid or a Tomonaga-Luttinger liquid in which the spectral weight
of single-particle excitations is almost vanishing. The spin susceptibility has
a temperature and wave-number dependence characteristic of itinerant-electron
magnetism. This type of itinerant-electron magnetism must also be possible in
the Heisenberg model.",1007.0764v1
2010-08-18,Spin-flavor oscillations of Dirac neutrinos described by relativistic quantum mechanics,"Spin-flavor oscillations of Dirac neutrinos in matter and a magnetic field
are studied using the method of relativistic quantum mechanics. Using the exact
solution of the wave equation for a massive neutrino, taking into account
external fields, the effective Hamiltonian governing neutrino spin-flavor
oscillations is derived. Then the The consistency of our approach with the
commonly used quantum mechanical method is demonstrated. The obtained
correction to the usual effective Hamiltonian results in the appearance of the
new resonance in neutrino oscillations. Applications to spin-flavor neutrino
oscillations in an expanding envelope of a supernova are discussed. In
particular, transitions between right-polarized electron neutrinos and
additional sterile neutrinos are studied for realistic background matter and
magnetic field distributions. The influence of other factors such as the
longitudinal magnetic field, the matter polarization, and the non-standard
contributions to the neutrino effective potential, is also analyzed.",1008.3115v3
2010-09-21,Realtime magnetic field sensing and imaging using a single spin in diamond,"The Zeeman splitting of a localized single spin can be used to construct a
magnetometer allowing high precision measurements of magnetic fields with
almost atomic spatial resolution. While sub-{\mu}T sensitivity can in principle
be obtained using pulsed techniques and long measurement times, a fast and
easy-to-use method without laborious data post-processing is desirable for a
scanning-probe approach with high spatial resolution. In order to measure the
resonance frequency in realtime, we applied a field-frequency lock to the
continuous wave ODMR signal of a single electron spin in a nanodiamond. In our
experiment, we achieved a sampling rate of up to 100 readings per second with a
sensitivity of 6 {\mu}T/$\sqrt{Hz}$. Using this method we have imaged the
microscopic field distribution around a magnetic wire. Images with \sim 30
{\mu}T resolution and 4096 sub-micron sized pixels were acquired in 10 minutes.
By measuring the field response of multiple spins on the same object we were
able to partly reconstruct the orientation of the field.",1009.4138v2
2010-11-09,Observation of exchange Coulomb interactions in the quantum Hall state at nu=3,"Coulomb exchange interactions of electrons in the nu=3 quantum Hall state are
determined from two inter-Landau level spin-flip excitations measured by
resonant inelastic light scattering. The two coupled collective excitations are
linked to inter-Landau level spin-flip transitions arising from the N=0 and N=1
Landau levels. The strong repulsion between the two spin-flip modes in the
long-wave limit is clearly manifested in spectra displaying Coulomb exchange
contributions that are comparable to the exchange energy for the quantum Hall
state at nu=1. Theoretical calculations within the Hartree-Fock approximation
are in a good agreement with measured energies of spin-flip collective
excitations.",1011.2022v1
2012-01-27,First-principles investigation of hyperfine interactions for nuclear spin entanglement in photo-excited fullerenes,"The study of hyperfine interactions in optically excited fullerenes has
recently acquired importance within the context of nuclear spin entanglement
for quantum information technology. We here report a first-principles
pseudopotential study of the hyperfine coupling parameters of optically excited
fullerene derivatives as well as small organic radicals. The calculations are
performed within the gauge-invariant projector-augmented wave method [C.
Pickard and F. Mauri, Phys. Rev. B. 63, 245101 (2001)]. In order to establish
the accuracy of this methodology we compare our results with all-electron
calculations and with experiment. In the case of fullerene derivatives we study
the hyperfine coupling in the spin-triplet exciton state and compare our
calculations with recent electron paramagnetic resonance measurements [M.
Schaffry et al., Phys. Rev. Lett. 104, 200501 (2010)]. We discuss our results
in light of a recent proposal for entangling remote nuclear spins in
photo-excited chromophores.",1201.5849v1
2012-01-30,Quantitative MRFM characterization of the autonomous and forced dynamics in a spin transfer nano-oscillator,"Using a magnetic resonance force microscope (MRFM), the power emitted by a
spin transfer nano-oscillator consisting of a normally magnetized Py$|$Cu$|$Py
circular nanopillar is measured both in the autonomous and forced regimes. From
the power behavior in the subcritical region of the autonomous dynamics, one
obtains a quantitative measurement of the threshold current and of the noise
level. Their field dependence directly yields both the spin torque efficiency
acting on the thin layer and the nature of the mode which first
auto-oscillates: the lowest energy, spatially most uniform spin-wave mode. From
the MRFM behavior in the forced dynamics, it is then demonstrated that in order
to phase-lock this auto-oscillating mode, the external source must have the
same spatial symmetry as the mode profile, i.e., a uniform microwave field must
be used rather than a microwave current flowing through the nanopillar.",1201.6344v1
2012-01-31,Nonreciprocal Directional Dichroism and Toroidalmagnons in Helical Magnets,"We investigate a dynamical magnetoelectric effect due to a magnetic resonance
in helical spin structures through the coupling between magnetization and
electric polarization via a spin current mechanism. We show that the magnon has
both the dynamical magnetic moment $\Delta M^\omega$ and the electric moment
$\Delta P^\omega$ ($\perp \Delta M^\omega$), i.e., a dynamical toroidal moment,
under external magnetic fields, and thus it is named the {\em toroidalmagnon}.
The toroidalmagnon exists in most conical spin structures owing to the
generality of the spin current mechanism. In the absorption of electromagnetic
waves, the toroidalmagnon excitation process generally induces a nonreciprocal
directional dichroism as a consequence of an interference of the magnetic and
electric responses.",1201.6458v1
2012-04-23,Low-energy Spin Excitation in Coexistent Phase of Antiferromagnetism and d-wave Superconductivity,"Nuclear quadrupole resonance measurements have shown evidences that the heavy
fermion compound CeRhIn$_5$ exhibits a coexistent phase with commensurate
antiferromagnetism and d-wave superconductivity. In order to clarify the nature
of the spin-excitations in the coexistent phase, we have applied the RPA method
to an itinerant model, where the effective interaction is given by two
mean-field terms of commensurate antiferromagnetism and d-wave
superconductivity. It is shown that, around the transition line between the
antiferromagnetic and the coexistent states, a low-energy incommensurate
spin-excitation is found to develop due to Fermi surface nesting. This feature
reminds of the switching of magnetic ordering wave vector observed in the
neutron diffraction. Further, we also calculate spin relaxation rate, which
gives a reasonable explanation of the temperature dependence of NQR relaxation
rate in the system with the coexistent ground state.",1204.5032v3
2012-04-28,Frustrated RVB states in 2D: classifications and short-range correlations,"Resonating valence bond (RVB) states are of crucial importance in our
intuitive understanding of quantum spin liquids in 2D. We systematically
classify short-range bosonic RVB states into symmetric or nematic spin liquids
by examining their flux patterns. We further map short-range bosonic RVB states
into projected BCS wave functions, on which we perform large-scale Monte Carlo
simulations without the minus sign problem. Our results clearly show that both
spin and dimer correlations decay exponentially in all the short-range
frustrated (non-bipartite or $Z_2$) bosonic RVB states we studied, indicating
that they are gapped $Z_2$ quantum spin liquids. Generically, we conjecture
that all short-range frustrated bosonic RVB states in 2D have only short-range
correlations.",1204.6381v4
2013-04-17,Black-hole perturbation theory: The asymptotic spectrum of the prolate spin-weighted spheroidal harmonics,"Prolate spin-weighted spheroidal harmonics play a key role in black-hole
perturbation theory. In particular, the highly damped quasinormal resonances of
rotating Kerr black holes are closely related to the asymptotic eigenvalues of
these important functions. We here present a novel and compact derivation of
the asymptotic eigenvalues of the prolate spin-weighted spheroidal harmonics.
Our analysis is based on a simple trick which transforms the corresponding
spin-weighted spheroidal angular equation into a Schr\""odinger-like wave
equation which is amenable to a standard WKB analysis. Our analytical results
for the prolate asymptotic spectrum agree with previous numerical computations
of the eigenvalues which appear in the literature.",1304.4683v1
2013-06-17,Magnetic excitations in the spin-1/2 triangular-lattice antiferromagnet Cs$_2$CuBr$_4$,"We report on high-field electron spin resonance (ESR) studies of magnetic
excitations in the spin-1/2 triangular-lattice antiferromagnet Cs$_2$CuBr$_4$.
Frequency-field diagrams of ESR excitations are measured for different
orientations of magnetic fields up to 25 T. We show that the substantial
zero-field energy gap, $\Delta\approx9.5$ K, observed in the low-temperature
excitation spectrum of Cs$_2$CuBr$_4$ [Zvyagin $et~al.$, Phys. Rev. Lett. 112,
077206 (2014)], is present well above $T_N$. Noticeably, the transition into
the long-range magnetically ordered phase does not significantly affect the
size of the gap, suggesting that even below $T_N$ the high-energy spin dynamics
in Cs$_2$CuBr$_4$ is determined by short-range-order spin correlations. The
experimental data are compared with results of model spin-wave-theory
calculations for spin-1/2 triangle-lattice antiferromagnet.",1306.3887v3
2013-08-02,Stretched exponential spin relaxation in organic superconductors,"Proton NMR measurements on the organic superconductor
$\kappa-(ET)_2Cu[N(CN)_2]Br$ ($T_C = 11.6$ K) exhibit stretched exponential
spin-lattice relaxation below $T\approx 25$ K, suggestive of an inhomogeneous
magnetic phase that develops in the normal state and coexists with
superconductivity. The onset of this phase coincides approximately with a large
normal state Nernst signal reported previously. By contrast, the closely
related superconductor $\kappa-(ET)_2Cu[(NCS)_2]Br$ ($T_C = 10.5$ K) shows
single exponential spin-lattice relaxation and a conventional Nernst effect.
The temperature range $T_C < T < 30$ K encompasses several phenomena in the
$\kappa-(ET)_2X$ conductors, including changes in conduction electron spin
resonance, electronic phase separation and the onset of antiferromagnetic
order. Analogous behavior in $La_{2-x}Sr_xCuO_4$ suggests that a density wave
may develop in $\kappa-(ET)_2Cu[N(CN)_2]Br$.",1308.0614v1
2014-02-09,Site specific spin dynamics in BaFe2As2: tuning the ground state by orbital differentiation,"The role of orbital differentiation on the emergence of superconductivity in
the Fe-based superconductors remains an open question to the scientific
community. In this investigation, we employ a suitable microscopic spin probe
technique, namely Electron Spin Resonance (ESR), to investigate this issue on
selected chemically substituted BaFe$_{2}$As$_{2}$ single crystals. As the
spin-density wave (SDW) phase is suppressed, we observe a clear increase of the
Fe 3$d$ bands anisotropy along with their localization at the FeAs plane. Such
an increase of the planar orbital content interestingly occurs independently on
the chemical substitution responsible for suppressing the SDW phase. As a
consequence, the magnetic fluctuations combined with the resultant particular
symmetry of the Fe 3$d$ bands are propitious ingredients to the emergence of
superconductivity in this class of materials.",1402.2001v1
2015-04-19,Motion of free spins and NMR imaging without a radio-frequency magnetic field,"NMR imaging without any radio-frequency magnetic field is explained by a
quantum treatment of independent spin~$\tfrac 12$. The total magnetization is
determined by means of their individual wave function. The theoretical
treatment, based on fundamental axioms of quantum mechanics and solving
explicitly the Schr\""{o}dinger equation with the kinetic energy part which
gives the motion of free spins, is recalled. It explains the phase shift of the
spin noise spectrum with its amplitude compared to the conventional NMR
spectrum. Moreover it explains also the relatively good signal to noise ratio
of NMR images obtained without a RF pulse. This derivation should be helpful
for new magnetic resonance imaging sequences or for developing quantum
computing by NMR.",1504.04882v1
2015-09-16,Antiferromagnetic order in CeCoIn5 oriented by spin-orbital coupling,"An incommensurate spin density wave ($Q$ phase) confined inside the
superconducting state at high basal plane magnetic field is an unique property
of the heavy fermion metal CeCoIn$_5$. The neutron scattering experiments and
the theoretical studies point out that this state come out from the soft mode
condensation of magnetic resonance excitations. We show that the fixation of
direction of antiferromagnetic modulations by a magnetic field reported by
Gerber et al., Nat. Phys. {\bf 10}, 126 (2014) is explained by spin-orbit
coupling. This result, obtained on the basis of quite general phenomenological
arguments, is supported by the microscopic derivation of the $\chi_{zz}$
susceptibility dependence on the mutual orientation of the basal plane magnetic
field and the direction of modulation of spin polarization in a multi-band
metal.",1509.04915v4
2016-01-26,Jahn-Teller effect in systems with strong on-site spin-orbit coupling,"When strong spin-orbit coupling removes orbital degeneracy, it would at the
same time appear to render the Jahn-Teller mechanism ineffective. We discuss
such a situation, the t_2g manifold of iridates, and show that, while the
Jahn-Teller effect does indeed not affect the j_eff=1/2 antiferromagnetically
ordered ground state, it leads to distinctive signatures in the j_eff=3/2
spin-orbit exciton. It allows for a hopping of the spin-orbit exciton between
the nearest neighbor sites without producing defects in the j_eff=1/2
antiferromagnet. This arises because the lattice-driven Jahn-Teller mechanism
only couples to the orbital degree of freedom, but is not sensitive to the
phase of the wave function that defines isospin j_z. This contrasts sharply
with purely electronic propagation, which conserves isospin, and presence of
Jahn-Teller coupling can explain some of the peculiar features of measured
resonant inelastic x-ray scattering spectra of Sr_2IrO_4.",1601.07069v1
2018-03-06,Refrigeration beyond weak internal coupling,"We investigate the performance of a three-spin quantum absorption
refrigerator using a refined open quantum system model valid across all
inter-spin coupling strengths. It describes the transition between previous
approximate models for the weak and the ultrastrong coupling limit, and it
predicts optimal refrigeration for moderately strong coupling, where both
approximations are inaccurate. Two effects impede a more effective cooling: the
coupling between the spins no longer reduces to a simple resonant energy
exchange (the rotating wave approximation fails), and the interactions with the
thermal baths become sensitive to the level splitting, thus opening additional
heat channels between the reservoirs. We identify the modified conditions of
refrigeration as a function of the inter-spin coupling strength, and we show
that, contrary to intuition, a high-temperature work reservoir thwarts
refrigeration in the strong coupling regime.",1803.02002v2
2019-11-21,The nature of the chemical bond in the dicarbon molecule,"The molecular dissociation energy has often been explained and discussed in
terms of singlet bonds, formed by bounded pairs of valence electrons. In this
work we use a highly correlated resonating valence bond ansatz, providing a
consistent paradigm for the chemical bond, where spin fluctuations are shown to
play a crucial role. Spin fluctuations are known to be important in magnetic
systems and correspond to the zero point motion of the spin waves emerging from
a magnetic broken symmetry state. Recently, in order to explain the excitation
spectrum of the carbon dimer, an unusual quadruple bond has been proposed.
Within our ansatz, a satisfactory description of the carbon dimer is determined
by the magnetic interaction of two Carbon atoms with antiferromagnetically
ordered S = 1 magnetic moments. This is a first step that, thanks to the highly
scalable and efficient quantum Monte Carlo technique, may open the way for
understanding challenging complex systems containing atoms with large spins
(e.g. transition metals).",1911.09748v4
2020-04-09,First-Principles Calculation of Spin and Orbital Contributions to Magnetically Ordered Moments in Sr$_{2}$IrO$_{4}$,"We show how an accurate first-principles treatment of the
canted-antiferromagnetic ground state of Sr$_2$IrO$_4$, a prototypical $5d$
correlated spin-orbit coupled material, can be obtained without invoking any
free parameters such as the Hubbard U or tuning the spin-orbit coupling
strength. Our theoretically predicted iridium magnetic moment of 0.250 $\mu_B$,
canted by 12.6$^{\circ}$ off the a-axis, is in accord with experimental
results. By resolving the magnetic moments into their spin and orbital
components, we show that our theoretically obtained variation of the magnetic
scattering amplitude $<M_{m}>$ as a function of the polarization angle is
consistent with recent non-resonant magnetic x-ray scattering measurements. The
computed value of the band gap (55 meV) is also in line with the corresponding
experimental values. A comparison of the band structure to that of the cuprates
suggests the presence of incommensurate charge-density wave phases in
Sr$_{2}$IrO$_{4}$.",2004.04759v1
2008-06-18,Selective Heating Mechanism of Magnetic Metal Oxides by Alternating Magnetic Field in Microwave Sintering Process,"The mechanism of rapid and selective heating of magnetic metal oxides under
the magnetic field of microwaves which continues beyond the Curie temperature $
T_{c} $ is identified by using the Heisenberg model. Monte Carlo calculations
based on the energy principle show that such heating is caused by non-resonant
response of electron spins in the unfilled 3d shell to the wave magnetic field.
Small spin reorientation thus generated leads to a large internal energy change
through the exchange interactions between spins, which becomes maximal around $
T_{c} $ for magnetite $ {\rm Fe}_{3}{\rm O}_{4} $. The dissipative spin
dynamics simulation yields the imaginary part of the magnetic susceptibility,
which becomes largest around $ T_{c} $ and for the microwave frequency around 2
GHz. Hematite $ {\rm Fe}_{2}{\rm O}_{3} $ with weak spontaneous magnetization
responds much less to microwaves as observed in experiments. The heating of
titanium oxide by microwave magnetic field only when oxygen defects are present
is also explained by our theory in terms of the absence of spontaneous
magnetization.",0806.3055v3
2019-10-31,Coherent spin pumping in a strongly coupled magnon-magnon hybrid system,"We experimentally identify coherent spin pumping in the magnon-magnon hybrid
modes of permalloy/yttrium iron garnet (Py/YIG) bilayers. Using broadband
ferromagnetic resonance, an ""avoided crossing"" is observed between the uniform
mode of Py and the spin wave mode of YIG due to the fieldlike interfacial
exchange coupling. We also identify additional linewidth suppression and
enhancement for the in-phase and out-of-phase hybrid modes, respectively,
\textcolor{black}{which can be interpreted as concerted dampinglike torque from
spin pumping}. Our analysis predicts inverse proportionality of both fieldlike
and dampinglike torques to the square root of the Py thickness, which
quantitatively agrees with experiments.",1910.14470v2
2020-05-11,Universal relations for hybridized $s$- and $p$-wave interactions from spin-orbital coupling,"In this work, we study the universal relations for one-dimensional
spin-orbital-coupled fermions near both $s$- and $p$-wave resonances using
effective field theory. Since the spin-orbital coupling mixes different partial
waves, a contact matrix is introduced to capture the non-trivial correlation
between dimers. We find the signature of the spin-orbital coupling appears at
the leading order for the off-diagonal components of the momentum distribution
matrix, which is proportional to $1/q^{3}$ ($q$ is the relative momentum). We
further derive the large frequency behavior of the Raman spectroscopy, which
serves as an independent measurable quantity for contacts. Finally, we give an
explicit example of contacts by considering a two-body problem.",2005.04997v2
2021-03-22,Calibration of Spin-Light Coupling by Coherently Induced Faraday Rotation,"Calibrating the strength of the light-matter interaction is an important
experimental task in quantum information and quantum state engineering
protocols. The strength of the off-resonant light-matter interaction in
multi-atom spin oscillators can be characterized by the coupling rate
$\Gamma_\text{S}$. Here we utilize the Coherently Induced Faraday Rotation
(CIFAR) signal for determining the coupling rate. The method is suited for both
continuous and pulsed readout of the spin oscillator, relying only on applying
a known polarization modulation to the probe laser beam and detecting a known
optical polarization component. Importantly, the method does not require
changes to the optical and magnetic fields performing the state preparation and
probing. The CIFAR signal is also independent of the probe beam photo-detection
quantum efficiency, and allows direct extraction of other parameters of the
interaction, such as the tensor coupling $\zeta_\text{S}$, and the damping rate
$\gamma_\text{S}$. We verify this method in the continuous wave regime, probing
a strongly coupled spin oscillator prepared in a warm cesium atomic vapour.",2103.11729v1
2023-02-23,Ultrafast laser-induced spin-lattice dynamics in the van der Waals antiferromagnet CoPS3,"CoPS3 stands out in the family of the van der Waals antiferromagnets XPS3
(X=Mn, Ni, Fe, Co) due to the unquenched orbital momentum of the magnetic Co2+
ions which is known to facilitate the coupling of spins to both electromagnetic
waves and lattice vibrations. Here, using a time-resolved magneto-optical
pump-probe technique we experimentally study the ultrafast laser-induced
dynamics of mutually correlated spins and lattice. It is shown that a
femtosecond laser pulse acts as an ultrafast heater and thus results in the
melting of the antiferromagnetic order. At the same time, the resonant pumping
of the 4T1g - 4T2g electronic transition in Co2+ ions effectively changes their
orbital momentum, giving rise to a mechanical force that moves the ions in the
direction parallel to the orientation of their spins, thus generating a
coherent Bg phonon mode at the frequency of about 4.7 THz.",2302.12104v1
2023-05-22,Quark distribution functions and spin-flavor structures in $N \to Δ$ transitions,"Transition generalized parton distributions have emerged as a novel tool for
studying the quantum chromodynamics (QCD) structure of resonances. They provide
an integrated picture of the transition form factors and the transition parton
distribution functions. In this study, we delve into the angular momentum (AM)
properties for the $N\to \Delta$ transition and its decomposition into the
orbital angular momentum and the intrinsic spin in the context of the quark
distribution functions. First, we explore the spin-flavor structures within the
framework of both the overlap representations of the three-quark light-cone
wave functions and the large $N_c$ limit of QCD. We then estimate the AM quark
distribution functions for the $N\to \Delta$ transition. Our analysis reveals a
substantial flavor asymmetry present in both the orbital angular momentum and
intrinsic spin components.",2305.12714v2
2023-10-03,Optical excitation of multiple standing spin modes in 3D optomagnonic nanocavities,"We report the first experimental observation of multiple standing spin modes
in 3D optomagnonic nanocavity formed by nanometer-sized iron-garnet
nanocylinder. We show that launching of standing spin modes is achieved due to
a high confinement of the optically generated effective magnetic field caused
by the localized optical resonance. Quantization and spin-wave mode
inhomogeneity is achieved in each of the three spatial dimensions. The
presented approach opens new horizons of 3D optomagnonics by combining
nanophotonic and magnonic functionalities within a single nanocavity.",2310.01974v1
2024-01-25,Universal collective Larmor-Silin mode emerging in magnetized correlated Dirac fermions,"Employing large-scale quantum Monte Carlo simulations, we find in magnetized
interacting Dirac fermion model, there emerges a new and universal collective
Larmor-Silin spin wave mode in the transverse dynamical spin susceptibility.
Such mode purely originates from the interaction among Dirac fermions and
distinguishes itself from the usual particle-hole continuum with finite
lifetime and clear dispersion, both at small and large momenta in a large
portion of the Brillouin zone. Our unbiased numerical results offer the dynamic
signature of this new collective excitations in interacting Dirac fermion
systems, and provide experimental guidance for inelastic neutron scattering,
electron spin resonance and other spectroscopic approaches in the investigation
of such universal collective modes in quantum Moire materials, topological
insulators and quantum spin liquid materials under magnetic field, with
quintessential interaction nature beyond the commonly assumed noninteracting
Dirac fermion or spinon approximations.",2401.14358v2
2024-03-01,Investigation of spin excitations and charge order in bulk crystals of the infinite-layer nickelate LaNiO$_2$,"Recent x-ray spectroscopic studies have revealed spin excitations and charge
density waves in thin films of infinite-layer (IL) nickelates. However,
clarifying whether the origin of these phenomena is intrinsic to the material
class or attributable to impurity phases in the films has presented a major
challenge. Here we utilize topotactic methods to synthesize bulk crystals of
the IL nickelate LaNiO$_2$ with crystallographically oriented surfaces. We
examine these crystals using resonant inelastic x-ray scattering (RIXS) at the
Ni $L_3$-edge to elucidate the spin and charge correlations in the bulk of the
material. While we detect the presence of prominent spin excitations in the
crystals, fingerprints of charge order are absent at the ordering vectors
identified in previous in thin-film studies. These results contribute to the
understanding of the bulk properties of LaNiO$_2$ and establish topotactically
synthesized crystals as viable complementary specimens for spectroscopic
investigations.",2403.00493v1
2003-10-31,Gravitational Waves from Hyper-Accretion onto Nascent Black Holes,"We examine the possibility that hyper-accretion onto newly born, black holes
occurs in highly intermittent, non-asymmetric fashion favorable to
gravitational wave emission in a neutrino cooled disk. This picture of
near-hole accretion is motivated by magneto-rotationally induced,
ultra-relativistic disk dynamics in the region of the flow bounded from below
by the marginally bound geodesic radius. For high spin values, a largely
coherent magnetic field in this region has the dynamical implication of compact
mass segregation at the displacement nodes of the non-axisymmetric, MRI modes.
When neutrino stress competes favorably for the disk dynamical structure, the
matter clumps may be rather dense and sufficiently long-lived to excite the
Quasi-Normal Ringing (a.k.a. QNR) modes of the Kerr geometry upon their
in-fall. We find that such accretion flow may drive bar-like, quadrupole
(l,m=2,2) modes in nearly resonant fashion for spin parameters $a \geq .9$. The
ensuing build up in strain amplitude of the undamped oscillations warrants a
brisk rate of energy deposition into gravitational waves. A detectability
assessment for the LIGO interferometers through the match filtering technique
is given by integrating the energy flux over a one second epoch of resonant
hyper-accretion at $1 \msun \sec^{-1}$. Thus, a $15 \msun$ Kerr black hole
spinning at $a \simeq .98$ ($f_{\rm QNR} \simeq 1677$ Hz), and located at 27
Mpc (e.g., GRB980425), will deliver a characteristic strain amplitude, $h_{\rm
char} \simeq 2.2_{-21}$, large enough to be detectable by LIGO II. If resonant
hyper-accretion were sustainable for a longer period (or at higher rates)
possibly associated with a second broad hump in a GRB light-curve, these
objects could be detected by LIGO I at very low redshifts.",0311001v1
2017-03-21,Using rf voltage induced ferromagnetic resonance to study the spin-wave density of states and the Gilbert damping in perpendicularly magnetized disks,"We study how the shape of the spinwave resonance lines in rf-voltage induced
FMR can be used to extract the spinwave density of states and the damping
within the precessing layer in nanoscale tunnel junctions that possess
perpendicular anisotropy. We work with a field applied along the easy axis to
preserve the uniaxial symmetry of the system. We describe the set-up to study
the susceptibility contributions of the spin waves in the field-frequency
space. We then identify the maximum device size above which the spinwaves can
no longer be studied in isolation as the linewidths of their responses make
them overlap. The rf-voltage induced signal is the sum of two voltages that
have comparable magnitudes: a first voltage that originates from the transverse
susceptibility and rectification by magnetoresistance and a second voltage that
arises from the non-linear longitudinal susceptibility and the resultant
time-averaged change of the micromagnetic configuration. The transverse and
longitudinal susceptibility signals have different dc bias dependences such
that they can be separated by measuring how the device rectifies the rf voltage
at different dc bias voltages. The transverse and longitudinal susceptibility
signals have different lineshapes; their joint studies can yield the Gilbert
damping of the free layer of the device with a degree of confidence that
compares well with standard FMR. Our method is illustrated on FeCoB-based free
layers in which the individual spin-waves can be sufficiently resolved only for
disk diameters below 200 nm. The resonance line shapes on devices with 90 nm
diameters are consistent with a Gilbert damping of 0.011. This damping of 0.011
exceeds the value of 0.008 measured on the unpatterned films, which indicates
that device-level measurements are needed for a correct evaluation of
dissipation.",1703.07310v2
2010-10-04,p-Wave Optical Feshbach Resonances in Yb-171,"We study the use of an optical Feshbach resonance to modify the p-wave
interaction between ultracold polarized Yb-171 spin-1/2 fermions. A laser
exciting two colliding atoms to the 1S_0 + 3P_1 channel can be detuned near a
purely-long-range excited molecular bound state. Such an exotic molecule has an
inner turning point far from the chemical binding region and thus
three-body-recombination in the Feshbach resonance will be highly suppressed in
contrast to that typically seen in a ground state p-wave magnetic Feshbach
resonance. We calculate the excited molecular bound-state spectrum using a
multichannel integration of the Schr\""{o}dinger equation, including an external
perturbation by a magnetic field. From the multichannel wave functions, we
calculate the Feshbach resonance properties, including the modification of the
elastic p-wave scattering volume and inelastic spontaneous scattering rate. The
use of magnetic fields and selection rules for polarized light yields a highly
controllable system. We apply this control to propose a toy model for
three-color superfluidity in an optical lattice for spin-polarized Yb-171,
where the three colors correspond to the three spatial orbitals of the first
excited p-band. We calculate the conditions under which tunneling and on-site
interactions are comparable, at which point quantum critical behavior is
possible.",1010.0465v2
2013-05-28,"Atomic magnetic resonance induced by amplitude-, frequency-, or polarization-modulated light","In recent years diode laser sources have become widespread and reliable tools
in magneto-optical spectroscopy. In particular, laser-driven atomic
magnetometers have found a wide range of practical applications. More recently,
so-called magnetically silent variants of atomic magnetometers have been
developed. While in conventional magnetometers the magnetic resonance
transitions between atomic sublevels are phase-coherently driven by a weak
oscillating magnetic field, silent magnetometers use schemes in which either
the frequency (FM) or the amplitude (AM) of the light beam is modulated. Here
we present a theoretical model that yields algebraic expressions for the
parameters of the multiple resonances that occur when either amplitude-,
frequency- or polarization-modulated light of circular polarization is used to
drive the magnetic resonance transition in a transverse magnetic field. The
relative magnitudes of the resonances that are observed in the transmitted
light intensity at harmonic m of the Larmor frequency \omega_L (either by DC or
phase sensitive detection at harmonics q of the modulation frequency
\omega_mod) of the transmitted light are expressed in terms of the Fourier
coefficients of the modulation function. Our approach is based on an atomic
multipole moment representation that is valid for spin-oriented atomic states
with arbitrary angular momentum F in the low light power limit. We find
excellent quantitative agreement with an experimental case study using
(square-wave) amplitude-modulated (AM) light.",1305.6574v1
2020-11-03,Theory of Photon-Assisted Magnetoacoustic Resonance as a New Probe of Quadrupole Dynamics,"Motivated by the recent progress of phonon-mediated control in quantum spin
devices, we propose a possibility of hybrid measurement using electron
paramagnetic resonance (EPR) and a surface acoustic wave (SAW). Considering
quadrupole-strain (QS) couplings suggested for silicon vacancies, we present a
minimum model of the two-level system to investigate a magnetoacoustic
resonance (MAR) coupled to various strain modes driven by the SAW. The
longitudinal and transverse QS couplings can be changed by rotating a magnetic
field, which depends on a combination of the strain modes. Using the Floquet
theory, we elucidate each coupling effect on the time-averaged transition
probability, especially focus on a single-phonon transition process. The
important result is that the longitudinal QS coupling brings about a sharp
photon-assisted resonance and leads to an abrupt change in the field-angle
dependent transition probability. Since this phonon transition process is
always accompanied by the photon transition, the field angle for the sharp
resonance peak can be detected by the EPR measurement. The hybrid EPR-MAR
measurement is useful to confirm the existence of quadrupole degrees of freedom
strongly coupled to elastic strains, and thus it is expected to be a
complementary probe for the precise evaluation of quadrupole properties.",2011.01440v1
2019-04-25,Double Quantum Dot scenario for spin resonance in current noise,"We show that interference between parallel currents through two quantum dots,
in presence of spin orbit interactions and strong on-site Coulomb repulsion,
leads to resonances in current noise at the corresponding Larmor frequencies.
An additional resonance at the difference of Larmor frequencies is present even
without spin-orbit interaction. The resonance lines have strength comparable to
the background shot noise and therefore can account for the numerous
observations of spin resonance in STM noise with non-polarized leads. We solve
also several other models that show similar resonances.",1904.11221v2
2021-01-27,Detection of electron spin resonance down to 10 K using localized spoof surface plasmon,"In this study, novel use of the electromagnetic field profile of a localized
spoof surface plasmonic mode to detect electron spin resonance is being
reported. The mode is supported on a resonator with a complementary metallic
spiral structure, etched on the ground plane of a microstrip line having a
characteristic impedance of 50 $\Omega$. The change in characteristics of the
mode of interest with lowering of temperature has been observed and analyzed.
Electron spin resonance spectra of a standard paramagnetic sample,
2,2-diphenyl-1-picrylhydrazyl, are recorded using this resonator down to 10 K.
Potential application of the mode in the detection of microwave Rashba
field-driven electron spin resonance has been discussed.",2101.11528v1
2002-01-16,Quantum Spin dynamics of the Bilayer Ferromagnet La(1.2)Sr(1.8)Mn2O7,"We construct a theory of spin wave excitations in the bilayer manganite
La(1.2)Sr(1.8)Mn2O7 based on the simplest possible double-exchange model, but
including leading quantum corrections to the spin wave dispersion and damping.
Comparison is made with recent inelastic neutron scattering experiments. We
find that quantum effects account for some part of the measured damping of spin
waves, but cannot by themselves explain the observed softening of spin waves at
the zone boundary. Furthermore a doping dependence of the total spin wave
dispersion and the optical spin wave gap is predicted.",0201269v1
2023-03-18,Spin waves in a superconductor,"Spin waves that can propagate in normal and superconducting metals are
investigated. Unlike normal metals, the velocity of spin waves becomes
temperature-dependent in a superconductor. The low frequency spin waves survive
within the narrow region below the superconducting transition temperature. At
low temperatures the high frequency waves alone can propagate with an
additional damping due to pair-breaking.",2303.10468v1
2015-12-17,Multi-$Q$ hexagonal spin density waves and dynamically generated spin-orbit coupling: time-reversal invariant analog of the chiral spin density wave,"We study hexagonal spin-channel (""triplet"") density waves with commensurate
$M$-point propagation vectors. We first show that the three $Q=M$ components of
the singlet charge density and charge-current density waves can be mapped to
multi-component $Q=0$ nonzero angular momentum order in three dimensions ($3D$)
with cubic crystal symmetry. This one-to-one correspondence is exploited to
define a symmetry classification for triplet $M$-point density waves using the
standard classification of spin-orbit coupled electronic liquid crystal phases
of a cubic crystal. Through this classification we naturally identify a set of
non-coplanar spin density and spin-current density waves: the chiral spin
density wave and its time-reversal invariant analog. These can be thought of as
$3D$ $L=2$ and $L=4$ spin-orbit coupled isotropic $\beta$-phase orders. In
contrast, uniaxial spin density waves are shown to correspond to
$\alpha$-phases. The non-coplanar triple-$M$ spin-current density wave realizes
a novel $2D$ semimetal state with three flavors of four-component spin-momentum
locked Dirac cones, protected by a crystal symmetry akin to non-symmorphic
symmetry, and sits at the boundary between a trivial and topological insulator.
In addition, we point out that a special class of classical spin states,
defined as classical spin states respecting all lattice symmetries up to global
spin rotation, are naturally obtained from the symmetry classification of
electronic triplet density waves. These symmetric classical spin states are the
classical long-range ordered limits of chiral spin liquids.",1512.05673v3
2000-12-29,Data analysis of gravitational-wave signals from spinning neutron stars. IV. An all-sky search,"We develop a set of data analysis tools for a realistic all-sky search for
continuous gravitational-wave signals. The methods that we present apply to
data from both the resonant bar detectors that are currently in operation and
the laser interferometric detectors that are in the final stages of
construction and commissioning. We show that with our techniques we shall be
able to perform an all-sky 2-day long coherent search of the narrow-band data
from the resonant bar EXPLORER with no loss of signals with the dimensionless
amplitude greater than $2.8\times10^{-23}$.",0012108v1
1998-05-30,Baryon resonances in a chiral confining model (I),"In this two part series a chiral confining model of baryons is used to
describe low--lying negative parity resonances $N^*$, $\Delta^*$, $\Lambda^*$
and $\Sigma^*$ in the mean field approximation. A physical baryon in this model
consists of interacting valence quarks, mesons and a color and chiral singlet
hybrid field coexisting inside a dynamically generated confining region. This
first paper presents the quark contribution to the masses and wave functions of
negative parity baryons calculated with an effective spin--isospin dependent
instanton induced interaction. It does not include meson exchanges between
quarks. The three--quark wave functions are used to calculate meson--excited
baryon vertex functions to lowest order in meson--quark coupling. When the
baryons are on mass--shell each of these vertex functions is a product of a
coupling constant and a form factor. As examples, quark contributions to $N^*$
hadronic form factors as well as axial coupling constants are extracted from
the vertex functions and problems with the analytical behaviour of the model
form factors are discussed. The second paper will examine the mesonic
corrections to excited baryon properties in the heavy baryon and one--loop
approximations.",9806001v1
1999-06-03,On the origin of the short range NN repulsion,"We calculate S-wave singlet and triplet NN phase shifts stemming from the
short-range flavor-spin hyperfine interaction between constituent quarks using
the resonating group method approach. A strong short-range repulsion is found
in both waves. A fair comparison is performed between the traditional picture,
relying on the colour-magnetic interaction, and the present one, relying on the
Goldstone boson exchange dynamics. It is shown that the latter one induces
essentially stronger repulsion, which is a very welcome feature. We also study
a sensitivity of phase shifts and wave function to extention from the
one-channel to three-channel resonating group method approximation.",9906008v2
2004-11-02,D-state configurations in the electromagnetic form factors of the nucleon and the Delta(1232) resonance,"The $\Delta-N$ electromagnetic transition form factors are calculated in the
Poincar\'e covariant quark model in three forms of relativistic kinematics.
Addition of $D-$state components to pure $S-$state model wave functions, chosen
so as to reproduce the empirical elastic electromagnetic nucleon form factors
with single constituent currents, brings the calculated $R_{EM}$ ratio for the
$\Delta(1232)\to N\gamma$ transition closer to the empirical values in instant
and point form kinematics. The calculated $R_{SM}$ ratio is insensitive to the
$D-$state component. In front form kinematics the substantial violation of the
angular condition for the spin 3/2 resonance transition amplitude in the
impulse approximation prevents a unique determination of $R_{EM}$ and $R_{SM}$,
both of which are very sensitive to $D-$state components. In no form of
kinematics do $D-$state deformations of the rest frame baryon wave functions
alone suffice for a description of the empirical values of these ratios.",0411012v1
2007-06-28,n alpha Resonating-Group Calculation with a Quark-Model G-Matrix NN Interaction,"We calculate n alpha phase-shifts and scattering observables in the
resonating-group method, using the nuclear-matter G-matrix of an SU_6
quark-model NN interaction. The G-matrix is generated in the recent
energy-independent procedure of the quark-model NN interaction with the
continuous prescription for intermediate spectra, by assuming an appropriate
Fermi momentum k_F=1.2 fm^-1. The n alpha RGM interaction kernels are evaluated
with explicit treatments of the nonlocality and momentum dependence of
partial-wave G-matrix components. The momentum dependence of the G-matrix
components is different for each of the nucleon-exchange and interaction types.
Without introducing any artificial parameters except for k_F, the central and
spin-orbit components of the n alpha Born kernel are found to have reasonable
strengths under the assumption of a rigid translationally invariant shell-model
wave function of the alpha-cluster. The characteristic behaviors of three
different exchange terms, corresponding to knockout, heavy-particle pickup and
nucleon-rearrangement processes, are essentially the same between the case of
previous local effective NN forces and the case of nonlocal G-matrix NN
interactions.",0706.4250v2
2009-08-20,Partial wave analysis of the reaction gamma p -> p omega$ and the search for nucleon resonances,"An event-based partial wave analysis (PWA) of the reaction gamma p -> p omega
has been performed on a high-statistics dataset obtained using the CLAS at
Jefferson Lab for center-of-mass energies from threshold up to 2.4 GeV. This
analysis benefits from access to the world's first high precision spin density
matrix element measurements, available to the event-based PWA through the decay
distribution of omega-> pi+ pi - pi0. The data confirm the dominance of the
t-channel pi0 exchange amplitude in the forward direction. The dominant
resonance contributions are consistent with the previously identified states
F[15](1680) and D[13](1700) near threshold, as well as the G[17](2190) at
higher energies. Suggestive evidence for the presence of a J(P)=5/2(+) state
around 2 GeV, a ""missing"" state, has also been found. Evidence for other states
is inconclusive.",0908.2911v3
2010-08-18,Modulation stabilization of Bloch oscillations of two-component Bose-Einstein condensates in optical lattices,"We study the Bloch oscillations (BOs) of two-component Bose-Einstein
condensates (BECs) trapped in spin-dependent optical lattices. Based on the
derived equations of motion of the wave packet in the basis of localized wave
functions of the lattice sites, the damping effect induced by the
intercomponent and intracomponent interactions to the BOs is explored
analytically and numerically. We also show that such damping of the BOs can be
suppressed entirely if all the atom-atom interactions are modulated
synchronously and harmonically in time with suitable frequency via the Feshbach
resonance. When the intercomponent and the intracomponent interactions have
inverse signs, we find that the long-living BOs and even the revival of the BOs
can be achieved via only statically modulating the configuration of optical
lattices. The results provide a valuable guidance for achieving long-living BOs
in the two-component BEC system by the Feshbach resonances and manipulating the
configuration of the optical lattices.",1008.3004v1
2015-02-20,Magneto-Plasmonics and Resonant Interaction of Light with Dynamic Magnetisation in Metallic and All-Dielectric Nanostructures (Review),"A significant interest in combining plasmonics and magnetism at the nanoscale
gains momentum in both photonics and magnetism sectors that are concerned with
the resonant enhancement of light-magnetic-matter interaction in
nanostructures. These efforts result in a considerable amount of literature,
which is difficult to collect and digest in limited time. Furthermore, there is
insufficient exchange of results between the two research sectors.
Consequently, the goal of this review paper is to bridge this gap by presenting
an overview of recent progress in the field of magneto-plasmonics from two
different points of view: magneto-plasmonics, and magnonics and magnetisation
dynamics. It is expected that this presentation style will make this review
paper of particular interest to both general physical audience and specialists
conducting research on photonics, plasmonics, Brillouin light scattering
spectroscopy of magnetic nanostructures and magneto-optical Kerr effect
magnetometry, as well as ultrafast all-optical and THz-wave excitation of spin
waves. Moreover, readers interested in a new, rapidly emerging field of
all-dielectric nanophotonics will find a section about all-magneto-dielectric
nanostructures.",1502.05783v1
2018-06-02,Experimental demonstration of topological waveguiding in elastic plates with local resonators,"It is recent that the emergence of topological insulators in condensed matter
physics has inspired analogous wave phenomena in mechanical systems, mostly in
the setting of discrete lattice models. Here we report a numerical and
experimental demonstration of topological waveguiding in a continuum plate. We
take a ubiquitous design of a bolted elastic plate and show that such a design
allows us to invoke the pseudo-spin Hall effect at remarkably low frequencies.
We harness the complex interaction of the bolts and the plate to show the
existence of a pair of double Dirac cones near the resonant frequency of the
bolt. The manipulation of bolted patterns results in the opening of multiple
topological bandgaps, including a complete bandgap that forbids all plate
modes. We demonstrate that inside this bandgap, the interface between two
topologically distinct zones can guide flexural waves crisply around sharp
bends.",1806.00655v1
2018-11-22,Consequences of semidiurnal thermal tides on hot Jupiters zonal mean flows,"Hot Jupiters are submitted to an intense stellar heating. The resulting
thermal tides can torque their atmospheres into asynchronous rotation, while
these planets are usually assumed to be locked into spin-orbit synchronization
with their host star. Particularly, the thermal atmospheric torque can be
greatly enhanced by the dynamical component of the tidal response, that is the
component associated with the propagation of internal waves. Owing to the
involved complex dynamics, semi-analytical approaches are crucial to understand
the physical mechanisms that are responsible for the frequency-resonant
behavior of thermal tides, and quantify the atmospheric tidal torque. In this
work, we revisit the early works by Arras \& Socrates (2010) and present an
improved modeling of thermal tides taking into account rotation and radiative
cooling. Using this new modeling, we compute analytically the atmospheric tidal
response of hot Jupiters and show that resonances associated with low-frequency
internal gravity waves are able to drive asynchronous zonal flows in the range
1-30 days.",1811.09214v1
2018-08-12,Broad Feshbach resonances in ultracold alkali-metal systems,"A comprehensive search for ""broad"" Feshbach resonances (FRs) in all possible
combinations of stable alkali-metal atoms is carried out, using a multi-channel
quantum-defect theory assisted by the analytic wave functions for a long-range
van-der-Waals potential. A number of new ""broad"" $s$-, $p$- and $d$-wave FRs in
the lowest-energy scattering channels, which are stable against two-body
dipolar spin-flip loss, are predicted and characterized. Our results also show
that ""broad"" FRs of $p$- or $d$-wave type that are free of two-body loss do not
exist between fermionic alkali-metal atoms for magnetic field up to 1000\,G.
These findings constitute helpful guidance on efforts towards experimental
study of high-partial-wave coupling induced many-body physics.",1808.03917v1
2023-11-23,Control and sorting of eccentric all-dielectric core-shell nanoparticles using two counter-propagating plane waves,"Many typical nanoscale structures consist of dielectric nanoparticles with an
inevitable oxide-generated coating around them. Depending on the fabrication
techniques, these coatings may not be homogeneous, and their distortion can
cause problems in the applications of such systems. Based on finite element
simulations, inhomogeneous core-shell nanoparticle systems are numerically
studied when illuminated with two counter-propagating plane waves in the
optical range. It is found that the electromagnetic field distortions caused by
the inhomogeneous system under Mie resonance conditions allow the system to
exhibit controllable one-directional impulsion and rotation, which mainly
depends on the offset between the core and shell. The overall geometry and
composition of the system also dictate the type of resonance being excited.
Overall, this ""photonic thruster"" effect consisting of an accelerating and
spinning projectile would provide stability to particle movement and
additionally establish a method to distinguish inhomogeneous from homogeneous
particles. The method can be scaled to a wide range of nanoscale dielectric
particles. Thus, the results are useful for detecting defects in nanosystems
with a simple concept and may open avenues for improving nanoparticle synthesis
methods.",2311.14060v1
1998-11-01,A study of the pi^0pi^0 system produced in charge exchange and central collisions,"A study of the $\pi^0\pi^0$ system produced in charge exchange $\pi^-p$
collisions at 38 and 100 GeV/c and in central $pp$ interactions at 450 GeV/c
has been carried out. The $S$ wave has rather a complicated structure in both
processes indicating the existence of several scalar resonances. The $f_0(980)$
and $f_0(1500)$ appear as dips at 1 and 1.5 GeV in the $S$ wave for charge
exchange reaction, and as shoulders at these masses in the $S$ wave for central
production. The production of the $f_0(980)$, $f_0(1300)$ and $f_0(1500)$ in
the reaction $pp \to p_f\pi^0\pi^0p_s$ as a function of the $dP_{T}$
kinematical filter shows the behaviour differed from what has been observed for
the undisputed $q\bar{q}$ mesons. An extra $f_0(2000)$ state is seen in the $S$
wave for charge exchange reaction as a dip at 2 GeV. Resonances with higher
spins, $f_2(1270)$, $f_4(2050)$ and $f_6(2510)$, have also been studied. All
the three mesons are produced in the reaction $\pi^-p\to\pi^0\pi^0{n}$ mainly
via an one-pion exchange for small $-t$, whereas a natural-parity exchange
domimates for large $-t$. The behaviour of the centrally produced $f_2(1270)$
as a function of the $dP_{T}$ is consistent with what has been observed for
other $q\bar{q}$ states.",9811207v1
2014-01-20,Diffractive Dissociation into Three-Pion Final States at COMPASS,"In order to study diffractive dissociation reactions, COMPASS has taken data
with a 190 GeV/$c$ pion beam impinging on a liquid hydrogen target in 2008 and
2009. At squared four-momentum transfers to the target t' between 0.1
GeV$^2/c^2$ and 1.0 GeV$^2/c^2$ the number of events with three pions in the
final state is about an order of magnitude larger than that acquired by any
previous experiment. In COMPASS, the three-pion final state can be studied in
the two channels $\pi^-\pi^-\pi^+$ and $\pi^-\pi^0\pi^0$. The large data sample
in particular for the $\pi^-\pi^-\pi^+$ channel allows to find even small
signals at the sub-percent level. The progress of the partial-wave analysis
will be shown. Compared to previous COMPASS results, the analysis is now
performed in bins of t', and the set of partial waves has been extended now
including waves up to spin 6. The information from the t' dependence of the
individual partial waves is very helpful in separating resonant and
non-resonant contributions. As a consistency check results from the
$\pi^-\pi^-\pi^+$ channel will be compared to the $\pi^-\pi^0\pi^0$ channel.",1401.4943v2
2008-12-01,On the validity of nonlinear Alfven resonance in space plasmas,"In the approximation of linear dissipative magnetohydrodynamics (MHD) it can
be shown that driven MHD waves in magnetic plasmas with high Reynolds number
exhibit a near resonant behaviour if the frequency of the wave becomes equal to
the local Alfven (or slow) frequency of a magnetic surface. This near resonant
behaviour is confined to a thin region, known as the dissipative layer, which
embraces the resonant magnetic surface. Although driven MHD waves have small
dimensionless amplitude far away from the resonant surface, this near-resonant
behaviour in the dissipative layer may cause a breakdown of linear theory. Our
aim is to study the nonlinear effects in the Alfven dissipative layer. In the
present paper, the method of simplified matched asymptotic expansions developed
for nonlinear slow resonant waves is used to describe nonlinear effects inside
the Alfven dissipative layer. The nonlinear corrections to resonant waves in
the Alfven dissipative layer are derived and it is proved that at the Alfven
resonance (with isotropic/anisotropic dissipation) wave dynamics can be
described by the linear theory with great accuracy.",0812.0291v1
2006-08-26,Coherent output of photons from coupled superconducting transmission line resonators controlled by charge qubits,"We study the coherent control of microwave photons propagating in a
superconducting waveguide consisting of coupled transmission line resonators,
each of which is connected to a tunable charge qubit. While these coupled line
resonators form an artificial photonic crystal with an engineered photonic band
structure, the charge qubits collectively behave as spin waves in the low
excitation limit, which modify the band-gap structure to slow and stop the
microwave propagation. The conceptual exploration here suggests an
electromagnetically controlled quantum device based on the on-chip circuit QED
for the coherent manipulation of photons, such as the dynamic creation of
laser-like output from the waveguide by pumping the artificial atoms for
population inversion.",0608577v4
2006-11-12,Magnetic resonance spectroscopy of perpendicularly magnetized permalloy multilayer disks,"Using a Magnetic Resonance Force Microscope, we compare the ferromagnetic
resonance spectra of individual micron-size disks with identical diameter, 1
$m$m, but different layer structures. For a disk composed of a single 43.3 nm
thick permalloy (Py) layer, the lowest energy mode in the perpendicular
configuration is the uniform precession. The higher energy modes are standing
spin-waves confined along the diameter of the disk. For a Cu(30)/Py(100)/Cu(30)
nm multilayer structure, it has been interpreted that the lowest energy mode
becomes a precession localized at the Cu/Py interfaces. When the multilayer is
changed to Py(100)/Cu(10)/Py(10) nm, this localized mode of the thick layer is
coupled to the precession of the thin layer.",0611307v3
2000-05-23,Pion electroproduction on the nucleon and the generalized GDH sum rule,"Results of the recently developed unitary isobar model (MAID) are presented
for the spin asymmetries, structure functions and relevant sum rules in the
resonance region. The model describes the presently available data for
single-pion photo- and electroproduction in the resonance region below Wcm = 2
GeV very well. It is based on Born terms and resonance contributions, and the
respective multipoles are constructed in a gauge-invariant and unitary way for
each partial wave. The eta production is included in a similar way, while the
contribution of more-pion and higher channels is modeled by comparison with the
total cross sections and simple phenomenological assumptions. Our evaluation of
the energy-weighted integrals is in good agreement for the proton but shows big
discrepancies for the neutron.",0005061v1
2002-12-14,"Shape coexistence in N=14 isotones: 19B, 24Ne and 28Si","Shape coexistence problems in N=14 isotones are studied with a microscopic
method of antisymmetrized molecular dynamics. The present calculations
reproduce features of deformation in 28Si, and predict possible shape
coexistence of neutron density in neutron-rich nuclei(19B and 24Ne). We also
systematically study the structures of the ground and excited states, and the
molecular resonances of 28Si. Besides the shape coexistence in the low-energy
region, the results indicate the high-lying levels with $\alpha$-cluster and
12C+16O molecular structures in 28Si, which are consistent with the observed
spin-assigned resonances. The resonance states above the threshold energies are
connected with the low-lying deformed states from a view point of molecular
excitation by discussing inter-cluster wave functions.",0212061v1
2008-10-22,Strong asymmetry of microwave absorption by bi-layer conducting ferromagnetic films in the microstrip-line based broadband ferromagnetic resonance,"Peculiarities of ferromagnetic resonance response of conducting magnetic
bi-layer films of nanometric thicknesses excited by microstrip microwave
transducers have been studied theoretically. Strong asymmetry of the response
has been found. Depending on the order of layers with respect to the transducer
either the first higher-order standing spin wave mode, or the fundamental mode
shows the largest response.
  Film conductivity and lowered symmetry of microwave fields of such
transducers are responsible for this behavior. Amplitude of which mode is
larger also depends on the driving frequency. This effect is explained as
shielding of the asymmetric transducer field by eddy currents in the films.
This shielding remains very efficient for films with thicknesses well below the
microwave skin depth. This effect may be useful for studying buried magnetic
interfaces and should be accounted for in future development of broadband
inductive ferromagnetic resonance methods.",0810.4020v1
2009-02-12,Analytical solutions for two atoms in a harmonic trap: p-wave interactions,"We derive analytical solutions for the system of two ultracold spin-polarized
fermions interacting in p wave and confined in an axially symmetric harmonic
trap. To this end we utilize p-wave pseudopotential with an energy-dependent
scattering volume. This allows to describe the scattering in tight trapping
potentials in the presence of scattering resonances. We verify predictions of
the pseudopotential treatment for some model interaction potential, obtaining
an excellent agreement with exact energy levels. Then we turn to the
experimentally relevant case of neutral atom interactions in the vicinity of a
p-wave Feshbach resonance. In the framework of the multichannel quantum-defect
theory we derive relatively simple formula for an energy-dependent scattering
volume, and later we apply it to investigate the energy spectrum of trapped
atoms close to the p-wave Feshbach resonance.",0902.2167v1
2009-04-02,"Serber symmetry, Large Nc and Yukawa-like One Boson Exchange Potentials","The Serber force has relative orbital parity symmetry and requires vanishing
NN interactions in partial waves with odd angular momentum. We illustrate how
this property is well fulfilled for spin triplet states with odd angular
momentum and violated for odd singlet states for realistic potentials but fails
for chiral potentials. We analyze how Serber symmetry can be accommodated
within a large Nc perspective when interpreted as a long distance symmetry. A
prerequisite for this is the numerical similarity of the scalar and vector
meson resonance masses. The conditions under which the resonance exchange
potential can be approximated by a Yukawa form are also discussed. While these
masses arise as poles on the Second Riemann in pi-pi scattering, we find that
within the large Nc expansion the corresponding Yukawa masses correspond
instead to a well defined large Nc approximation to the pole which cannot be
distinguished from their location as Breit-Wigner resonances.",0904.0421v1
2009-09-18,Efficient Generation of a Maximally Entangled State by Repeated On- and Off-Resonant Scattering of Ancilla Qubits,"A scheme for preparing two fixed non-interacting qubits in a maximally
entangled state is presented. By repeating on- and off-resonant scattering of
ancilla qubits, the state of the target qubits is driven from an arbitrary
initial state into the singlet state with probability 1 (perfect efficiency).
Neither the preparation nor the post-selection of the ancilla spin state is
required. The convergence from an arbitrary input state to the unique fixed
point (mixing property) is proved rigorously, and its robustness is
investigated, by scrutinizing the effects of imperfections in the incident wave
of the ancilla, such as mistuning to a resonant momentum, imperfect
monochromatization, and fluctuation of the incident momentum, as well as
detector efficiency.",0909.3401v2
2011-11-21,Electronic phase transitions in Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ epitaxial thin films revealed by resonant soft x-ray scattering,"We report the study of magnetic and orbital order in
Pr$_{0.5}$Ca$_{0.5}$MnO$_3$ epitaxial thin films grown on
(LaAlO$_3$)$_{0.3}$-(SrAl$_{0.5}$Ta$_{0.5}$O$_3$)$_{0.7}$ (LSAT) (011)$_c$. In
a new experimental approach, the polarization and energy dependence of resonant
soft x-ray scattering are used to reveal significant modifications of the
magnetic order in the film as compared to the bulk, namely (i) a different
magnetic ordering wave vector, (ii) a different magnetic easy axis and (iii) an
additional magnetic reordering transition at low temperatures. These
observations indicate a strong impact of the epitaxial strain on the spin
order, which is mediated by the orbital degrees of freedom and which provides a
promising route to tune the magnetic properties of manganite films. Our results
further demonstrate that resonant soft x-ray scattering is a very suitable
technique to study the magnetism in thin films, to which neutron scattering
cannot easily be applied due to the small sample volume.",1111.4725v1
2013-11-21,Magnetization Enhancement in Magnetite Nanoparticles Capped with Alginic Acid,"We report on the effect of organic acid capping on the behavior of magnetite
nanoparticles. The nanoparticles of magnetite were obtained using microwave
activated process, and the magnetic properties as well as the electron magnetic
resonance behavior were studied for the Fe3O4 nanoparticles capped with alginic
acid. The capped nanoparticles exhibit improved crystalline structure of the
surface which leads to an enhanced magnetization. The saturation magnetization
Ms increases to ~75% of the bulk magnetization. The improved structure also
facilitates quantization of spin-wave spectrum in the finite size nanoparticles
and this in turn is responsible for unconventional behavior at low
temperatures. In magnetic resonance these anomalies are manifested as an
unusual increase in the resonant field Hr(T) and also as a maximum of the
spectroscopic splitting geff parameter at low temperatures. The unconventional
behavior of the nanoparticles also leads to pronounced upturn of magnetization
at low temperatures and a deviation from the Bloch law M(T) T^3/2.",1311.5379v1
2015-11-30,Enhancement of Rydberg-mediated single-photon nonlinearities by electrically tuned Förster Resonances,"Mapping the strong interaction between Rydberg atoms onto single photons via
electromagnetically induced transparency enables manipulation of light on the
single photon level and novel few-photon devices such as all-optical switches
and transistors operated by individual photons. Here, we demonstrate
experimentally that Stark-tuned F\""orster resonances can substantially increase
this effective interaction between individual photons. This technique boosts
the gain of a single-photon transistor to over 100, enhances the
non-destructive detection of single Rydberg atoms to a fidelity beyond 0.8, and
enables high precision spectroscopy on Rydberg pair states. On top, we achieve
a gain larger than 2 with gate photon read-out after the transistor operation.
Theory models for Rydberg polariton propagation on F\""orster resonance and for
the projection of the stored spin-wave yield excellent agreement to our data
and successfully identify the main decoherence mechanism of the Rydberg
transistor, paving the way towards photonic quantum gates.",1511.09445v3
2018-07-16,High-precision gravimeter based on a nano-mechanical resonator hybrid with an electron spin,"We show that the gravitational acceleration can be measured with the
matter-wave Ramsey interferometry, by using a nitrogen-vacancy center coupled
to a nano-mechanical resonator. We propose two experimental methods to realize
the Hamiltonian, by using either a cantilever resonator or a trapped
nanoparticle. The scheme is robust against the thermal noise, and could be
realized at the temperature much higher than the quantum regime one. The
effects of decoherence on the interferometry fringe visibility is caculated,
including the mechanical motional decay and dephasing of the nitrogen-vacancy
center. In addition, we demonstrate that under the various sources of random
and systematic noises, our gravimeter can be made on-chip and achieving a high
measurement precision. Under experimental feasible parameters, the proposed
gravimeter could achieve $10^{-10}$ relative precision.",1807.05671v1
2018-08-12,Resonant Driving induced Ferromagnetism in the Fermi Hubbard Model,"In this letter we consider quantum phases and the phase diagram of a Fermi
Hubbard model under periodic driving that has been realized in recent cold atom
experiments, in particular, when the driving frequency is resonant with the
interaction energy. Due to the resonant driving, the effective Hamiltonian
contains a correlated hopping term where the density occupation strongly
modifies the hopping strength. Focusing on half filling, in addition to the
charge and spin density wave phases, large regions of ferromagnetic phase and
phase separation are discovered in the weakly interacting regime. The mechanism
of this ferromagnetism is attributed to the correlated hopping because the
hopping strength within a ferromagnetic domain is normalized to a larger value
than the hopping strength across the domain. Thus, the kinetic energy favors a
large ferromagnetic domain and consequently drives the system into a
ferromagnetic phase. We note that this is a different mechanism in contrast to
the well-known Stoner mechanism for ferromagnetism where the ferromagnetism is
driven by interaction energy.",1808.03966v2
2020-11-13,Probing the indistinguishability of single photons generated by Rydberg atomic ensembles,"We investigate the indistinguishability of single photons retrieved from
collective Rydberg excitations in cold atomic ensembles. The Rydberg spin waves
are created either by off resonant two-photon excitation to the Rydberg state
or by Rydberg electromagnetically induced transparency. To assess the
indistinguishability of the generated single photons, we perform Hong-Ou-Mandel
experiments between the single photons and weak coherent states of light. We
analyze the indistinguishability of the single photons as a function of the
detection window and for photons generated by off-resonant excitation we infer
high value of indistinguishability going from 89% for the full waveform to 98%
for small detection windows. In the same way, we also investigate for the first
time the indistinguishability of single photons generated by Rydberg EIT,
showing values lower than those corresponding to single photons generated by
off-resonant excitation. These results are relevant for the use of Rydberg
atoms as quantum network nodes.",2011.06901v1
2019-10-23,$Ω$ baryon spectrum and their decays in a constituent quark model,"Combining the recent developments of the observations of $\Omega$ sates we
calculate the $\Omega$ spectrum up to the $N=2$ shell within a nonrelativistic
constituent quark potential model. Furthermore, the strong and radiative decay
properties for the $\Omega$ resonances within the $N=2$ shell are evaluated by
using the masses and wave functions obtained from the potential model. It is
found that the newly observed $\Omega(2012)$ resonance is most likely to be the
spin-parity $J^P=3/2^-$ $1P$-wave state $\Omega(1^{2}P_{3/2^{-}})$, it also has
a large potential to be observed in the $\Omega(1672)\gamma$ channel. Our
calculation shows that the 1$P$-, 1$D$-, and 2$S$-wave $\Omega$ baryons have a
relatively narrow decay width of less than 50 MeV. Based on the obtained decay
properties and mass spectrum, we further suggest optimum channels and mass
regions to find the missing $\Omega$ resonances via the strong and/or radiative
decay processes.",1910.10322v1
2020-02-11,Pentaquark components in low-lying baryon resonances,"We study pentaquark states of both light $q^4\bar q$ and hidden heavy $q^3
Q\bar Q$ (q = u,d,s quark in SU(3) flavor symmetry; Q = c, b quark) systems
with a general group theory approach in the constituent quark model, and the
spectrum of light baryon resonances in the ansatz that the $l=1$ baryon states
may consist of the $q^3$ as well as $q^4\bar q$ pentaquark component. The model
is fitted to ground state baryons and light baryon resonances which are
believed to be normal three-quark states. The work reveals that the
$N(1535)1/2^{-}$ and $N(1520)3/2^-$ may consist of a large $q^4\bar q$
component while the $N(1895)1/2^{-}$ and $N(1875)3/2^-$ are respectively their
partners, and the $N^+(1685)$ might be a $q^4\bar q$ state. By the way, a new
set of color-spin-flavor-spatial wave function for $q^3 Q\bar Q$ systems in the
compact pentaquark picture are constructed systematically for studying hidden
charm pentaquark states.",2002.04230v2
2022-02-16,Quantum interference of resonance fluorescence from Germanium-vacancy color centers in diamond,"Resonance fluorescence from a quantum emitter is an ideal source to extract
indistinguishable photons. By using the cross polarization to suppress the
laser scattering, we observed resonance fluorescence from GeV color centers in
diamond at cryogenic temperature. The Fourier-transform-limited linewidth
emission with $T_2/2T_1\sim0.86$ allows for two-photon interference based on
single GeV color center. Under pulsed excitation, the 24 ns separated photons
exhibit a Hong-Ou-Mandel visibility of $0.604\pm0.022$, while the
continuous-wave excitation leads to a coalescence time window of 1.05 radiative
lifetime. Together with single-shot readout of spin states, it paves the way
towards building a quantum network with GeV color centers in diamond.",2202.07906v1
2023-08-07,Quantum synchronization and entanglement of dissipative qubits coupled to a resonator,"We study the properties of a driven cavity coupled to several qubits in the
framework of a dissipative Jaynes-Cummings model. We show that the rotating
wave approximation (RWA) allows to reduce the description of original driven
model to an effective Jaynes-Cummings model with strong coupling between
photons and qubits. Two semi-analytical approaches are developed to describe
the steady state of this system. We first treat the weak dissipation limit
where we derive perturbative series of rate equations that converge to the
exact RWA steady-state except near the cavity resonance. This approach exactly
describes the multi-photon resonances in the system. Then in the strong
dissipation limit we introduce a semiclassical approximation which allows to
reproduce the mean spin-projections and cavity state. This approach reproduces
the RWA exactly in the strong dissipation limit but provides good qualitative
trends even in more quantum regimes. We then focus on quantum synchronization
of qubits through their coupling to the cavity. We demonstrate the entangled
steady state of a pair of qubits synchronized through their interaction with a
driven cavity in presence of dissipation and decoherence. Finally we discuss
synchronization of a larger number of qubits.",2308.03617v1
2024-03-23,Controllable bipolaron formation unveiling structural features of trap states in organic charge transport,"Magnetic resonance methods offer a unique chance for in-depth study of
conductive organic material systems, not only accounts for number of charge
carriers, but also allows manipulations of spin dynamics of particles. Here we
present a study of continuous-wave electrically detected magnetic resonance on
a range of organic conjugate polymers under transistor architecture, with
tunability in both carrier concentration and drifting electric field. We
demonstrate the general existence of bipolaron between mobile and trapped
charges at the magnetic resonance condition, then estimates the wavefunction
expansion of charge carriers on their hopping sites along conductive pathways.
This finding allows direct observation of energetically disordered trap sites
under the charge hopping picture, linking-up the microscopic structural
properties to the bulk electronic performances.",2403.15965v2
2002-10-18,Magnetic Resonant X-Ray Scattering in KCuF3,"We study the magnetic resonant x-ray scattering (RXS) spectra around the $K$
edge of Cu in KCuF$_3$ on the basis of an {\em ab initio} calculation. We use
the full-potential linearlized augmented plane wave method in the LDA$+U$
scheme, and introduce the lattice distortion as inputs of the calculation.
  We obtain finite intensity on magnetic superlattice spots, about three orders
of magnitude smaller than on orbital superlattice spots, by taking account of
the spin-orbit interaction (SOI). No intensity appears without the SOI,
indicating that the intensity arises not from the spin polarization but from
the orbital polarization in $4p$ states. The present calculation reproduces
well the experimental spectra as functions of photon energy and of azimuthal
angle. We also calculate the RXS intensity on orbital superlattice spots. It is
found that the intensity increases with increasing Jahn-Teller distortion. The
spectra remain nearly the same in the nonmagnetic state given by the simple
LDA, in which the orbital polarization in the 3d states is much smaller. This
strongly suggests that the intensity on orbital spots is mainly controlled by
the lattice distortion, not by the 3d orbital order itself.",0210396v1
2011-04-15,Resonating color state and emergent chromodynamics in the kagome antiferromagnet,"We argue that the spin-wave breakdown in the Heisenberg kagome
antiferromagnet signals an instability of the ground state and leads, through
an emergent local constraint, to a quantum dynamics described by a gauge theory
similar to that of chromodynamics. For integer spins, we show that the quantum
fluctuations of the gauge modes select the sqrt(3)xsqrt(3) Neel state with an
on-site moment renormalized by color resonances. We find non-magnetic
low-energy excitations that may be responsible for a deconfinement ""transition""
at experimentally accessible temperatures which we estimate.",1104.3033v3
2012-06-22,Separable potential model for meson-baryon interaction beyond the S-wave,"A model for low-energy meson-baryon interaction in the strange sector is
presented. The interaction is described in terms of separable potentials with
multiple partial waves considered. A general solution of Lippmann-Schwinger
equation for the scattering of spin zero and spin one-half particles is
derived.
  Next, the general framework is applied to the $\bar{K}N$ sector in a simple
model with only the S- and P-waves taken into account. The separable potential
is designed to match the chiral perturbation theory at lowest nontrivial order.
It is shown that although a simple model with three free parameters works well
for the S-wave, it fails to reproduce the P-wave features of kaon-nucleon
physics. Most importantly, the P-wave interaction is too weak to express a
resonant behavior that could be identified as $\Sigma(1385)$ resonance.",1206.5168v2
2014-05-21,Theoretical approach to resonant inelastic x-ray scattering in iron-based superconductors at the energy scale of the superconducting gap,"We develop a phenomenological theory to predict the characteristic features
of the momentum-dependent scattering amplitude in resonant inelastic x-ray
scattering (RIXS) at the energy scale of the superconducting gap in iron-based
superconductors. Taking into account all relevant orbital states as well as
their specific content along the Fermi surface we evaluate the charge and spin
dynamical structure factors for the compounds LaOFeAs and LiFeAs, based on
tight-binding models which are fully consistent with recent angle-resolved
photoemission spectroscopy (ARPES) data. We find a characteristic intensity
redistribution between charge and spin dynamical structure factors which
discriminates between sign-reversing and sign-preserving quasiparticle
excitations. Consequently, our results show that RIXS spectra can distinguish
between $s_\pm$ and $s_{++}$ wave gap functions in the singlet pairing case. In
addition, we find that an analogous intensity redistribution at small momenta
can reveal the presence of a chiral $p$-wave triplet pairing.",1405.5556v2
2015-08-07,Neutron diffraction investigation of the H-T phase diagram above the longitudinal incommensurate phase of BaCo2V2O8,"The quasi-one-dimensional antiferromagnetic Ising-like compound BaCo2V2O8 has
been shown to be describable by the Tomonaga-Luttinger liquid theory in its
gapless phase induced by a magnetic field applied along the Ising axis. Above
3.9 T, this leads to an exotic field-induced low-temperature magnetic order,
made of a longitudinal incommensurate spin-density wave, stabilized by weak
interchain interactions. By single-crystal neutron diffraction we explore the
destabilization of this phase at a higher magnetic field. We evidence a
transition at around 8.5 T towards a more conventional magnetic structure with
antiferromagnetic components in the plane perpendicular to the magnetic field.
The phase diagram boundaries and the nature of this second field-induced phase
are discussed with respect to previous results obtained by means of nuclear
magnetic resonance and electron spin resonance, and in the framework of the
simple model based on the Tomonaga-Luttinger liquid theory, which obviously has
to be refined in this complex system.",1508.01815v1
2018-06-16,Signature of the $s$-wave regime high above ultralow temperatures,"Physical processes involving charge transfer, spin exchange, or excitation
exchange often occur in conditions of resonant scattering. We show that the
$s$-wave contribution can be used to obtain a good approximation for the full
cross section. This approximation is found to be valid for a wide range of
scattering energies, including high above the Wigner regime, where many partial
waves contribute. We derive an analytical expression for the exchange cross
section and demonstrate its relationship to the Langevin cross section. We give
examples for resonant charge transfer as well as spin-flip and excitation
exchange. Our approximation can be used to gain information about the $s$-wave
regime from data obtained at much higher temperatures, which would be
advantageous for systems where the ultracold quantum regime is not easily
reachable.",1806.06162v1
2020-06-19,Coupled skyrmion breathing modes in synthetic ferri- and antiferromagnets,"We present micromagnetic simulations of the dynamic GHz-range resonance modes
of skyrmions excited by either out-of-plane ac magnetic fields or spin torques
in prototypical synthetic ferri- and antiferromagnetic trilayer structures. The
observed features in the calculated power spectra exhibit a systematic
dependence on the coupling strength between the individual magnetic layers and
are related to pure in-phase and anti-phase breathing modes as well as to
hybridizations of breathing and spin-wave modes that are characteristic for the
considered circular-shaped geometry. The experimental detection of these
resonant oscillation modes may provide a means for skyrmion sensing
applications and for the general characterization of skyrmion states in
multilayer stacks with antiferromagnetic interlayer exchange coupling.",2006.11318v2
2021-11-21,Antiferromagnetic resonance in the cubic iridium hexahalides (NH$_4$)$_2$IrCl$_6$ and K$_2$IrCl$_6$,"We report on high-field electron spin resonance studies of two iridium
hexahalide compounds, (NH$_4$)$_2$IrCl$_6$ and K$_2$IrCl$_6$. In the
paramagnetic state, our measurements reveal isotropic $g$-factors $g = 1.79$(1)
for the Ir$^{4+}$ ions, in agreement with their cubic symmetries. Most
importantly, in the magnetically ordered state, we observe two magnon modes
with zero-field gaps of 11.3 and 14.2 K for (NH$_4$)$_2$IrCl$_6$ and
K$_2$IrCl$_6$, respectively. Based on that and using linear spin-wave theory,
we estimate the nearest-neighbor exchange couplings and anisotropic Kitaev
interactions, $J_1/k_B=10.3$ K, $K/k_B=0.7$ K for (NH$_4$)$_2$IrCl$_6$, and
$J_1/k_B=13.8$ K, $K/k_B=0.9$ K for K$_2$IrCl$_6$, revealing the
nearest-neighbor Heisenberg coupling as the leading interaction term, with only
a weak Kitaev anisotropy.",2111.10884v1
2024-03-11,Tidal synchronization trapping in stars and planets with convective envelopes,"Tidal torques can alter the spins of tidally interacting stars and planets,
usually over shorter timescales than the tidal damping of orbital separations
or eccentricities. Simple tidal models predict that in eccentric binary or
planetary systems, rotation periods will evolve toward a ""pseudosynchronous""
ratio with the orbital period. However, this prediction does not account for
""inertial"" waves that are present in stars or gaseous planets with (i)
convective envelopes, and (ii) even very slow rotation. We demonstrate that
tidal driving of inertial oscillations in eccentric systems generically
produces a network of stable ""synchronization traps"" at ratios of orbital to
rotation period that are simple to predict, but can deviate significantly from
pseudosynchronization. The mechanism underlying spin synchronization trapping
is similar to tidal resonance locking, involving a balance between torques that
is maintained automatically by the scaling of inertial mode frequencies with
the rotation rate. In contrast with many resonance locking scenarios, however,
the torque balance required for synchronization trapping need not drive mode
amplitudes to nonlinearity. Synchronization traps may provide an explanation
for low-mass stars and hot Jupiters with observed rotation rates that deviate
from pseudosynchronous or synchronous expectations.",2403.06979v2
2001-11-14,"Magnetic Ordering, Orbital Ordering and Resonant X-ray Scattering in Perovskite Titanates","The effective Hamiltonian for perovskite titanates is derived by taking into
account the three-fold degeneracy of $t_{2g}$ orbitals and the strong
electron-electron interactions. The magnetic and orbital ordered phases are
studied in the mean-field approximation applied to the effective Hamiltonian. A
large degeneracy of the orbital states in the ferromagnetic phase is found in
contrast to the case of the doubly degenerate $e_g$ orbitals. Lifting of this
orbital degeneracy due to lattice distortions and spin-orbit coupling is
examined. A general form for the scattering cross section of the resonant x-ray
scattering is derived and is applied to the recent experimental results in
YTiO$_3$. The spin wave dispersion relation in the orbital ordered YTiO$_3$ is
also studied.",0111249v1
2006-06-30,NMR evidence for Friedel-like oscillations in the CuO chains of ortho-II YBa$_2$Cu$_3$O$_{6.5}$,"Nuclear magnetic resonance (NMR) measurements of CuO chains of detwinned
Ortho-II YBa$_2$Cu$_3$O$_{6.5}$ (YBCO6.5) single crystals reveal unusual and
remarkable properties. The chain Cu resonance broadens significantly, but
gradually, on cooling from room temperature. The lineshape and its temperature
dependence are substantially different from that of a conventional spin/charge
density wave (S/CDW) phase transition. Instead, the line broadening is
attributed to small amplitude static spin and charge density oscillations with
spatially varying amplitudes connected with the ends of the finite length
chains. The influence of this CuO chain phenomenon is also clearly manifested
in the plane Cu NMR.",0606811v1
2003-02-21,An analysis of the reaction pp --> ppηnear threshold,"It is shown that most of the available data on the $pp\to pp\eta$ reaction,
including the invariant mass distributions in the $pp\to pp\eta$ reaction
recently measured at COSY, can be understood in terms of the partial-wave
amplitudes involving final $pp$ $S$ and $P$ states and the $\eta$ meson s-wave.
This finding, together with the fact that results within a meson--exchange
model are especially sensitive to the details of the excitation mechanism of
the $S_{11}(1535)$ resonance, demonstrates the possibility of investigating the
properties of this resonance in $NN$ collisions. The spin correlation function
$C_{xx}$ is shown to disentangle the $S$- and $P$-wave contributions. It is
also argued that spin correlations may be used to help constrain the
contributions of the amplitudes corresponding to the final $pp$ $^3P_0$",0302061v3
2010-12-07,Homogeneous coexistence of SDW and SC states in CaFe(1-x)Co(x)AsF studied by nuclear magnetic resonance,"We investigated the homogeneous coexistence of spin-density-wave (SDW) and
superconducting (SC) states via 75As-nuclear magnetic resonance (NMR) in
CaFe(1-x)Co(x)AsF and found that the electronic and magnetic properties of this
compound are intermediate between those of LaFeAsO(1-x)F(x) and
Ba(Fe(1-x)Co(x))2As2. For 6% Co-doped samples, the paramagnetic spectral weight
completely disappears in the crossover regime between the SDW and SC phases
followed by the anomalous behavior of relaxation rate (1/T1), implying that the
two phases are not segregated. The 59Co-NMR spectra show that spin moments are
not commensurate but spatially modulated. These experimental results suggest
that incommensurate SDW (IC-SDW) and SC states are compatible in this compound.",1012.1432v2
2012-08-21,Optimized production of ultracold ground-state molecules: Stabilization employing potentials with ion-pair character and strong spin-orbit coupling,"We discuss the production of ultracold molecules in their electronic ground
state by photoassociation employing electronically excited states with ion-pair
character and strong spin-orbit interaction. A short photoassociation laser
pulse drives a non-resonant three-photon transition for alkali atoms colliding
in their lowest triplet state. The excited state wave packet is transferred to
the ground electronic state by a second laser pulse, driving a resonant
two-photon transition. After analyzing the transition matrix elements governing
the stabilization step, we discuss the efficiency of population transfer using
transform-limited and linearly chirped laser pulses. Finally, we employ optimal
control theory to find the most efficient stabilization pathways. We find that
the stabilization efficiency can be increased by one and two orders of
magnitude for linearly chirped and optimally shaped laser pulses, respectively.",1208.4331v2
2014-07-09,Interaction Driven Subgap Spin Exciton in the Kondo Insulator SmB6,"Using inelastic neutron scattering, we map a 14 meV coherent resonant mode in
the topological Kondo insulator SmB6 and describe its relation to the low
energy insulating band structure. The resonant intensity is confined to the X
and R high symmetry points, repeating outside the first Brillouin zone and
dispersing less than 2 meV, with a 5d-like magnetic form factor. We present a
slave-boson treatment of the Anderson Hamiltonian with a third neighbor
dominated hybridized band structure. This approach produces a spin exciton
below the charge gap with features that are consistent with the observed
neutron scattering. We find that maxima in the wave vector dependence of the
inelastic neutron scattering indicate band inversion.",1407.2647v2
2015-08-20,Superstrong Coupling of a Microwave Cavity to YIG Magnons,"Multiple-post reentrant 3D lumped cavity modes have been realized to design
the concept of discrete Whispering Gallery and Fabry-Perot-like Modes for
multimode microwave Quantum Electrodynamics experiments. Using a magnon
spin-wave resonance of a submillimeter-sized Yttrium-Iron-Garnet sphere at
milliKelvin temperatures and a four-post cavity, we demonstrate the
ultra-strong coupling regime between discrete Whispering Gallery Modes and a
magnon resonance with strength of 1.84 GHz. By increasing the number of posts
to eight and arranging them in a D$_4$ symmetry pattern, we expand the mode
structure to that of a discrete Fabry-Perot cavity and modify the Free Spectral
Range (FSR). We reach the superstrong coupling regime, where spin-photon
coupling strength is larger than FSR, with coupling strength in the 1.1 to 1.5
GHz range.",1508.04967v3
2015-10-26,The $Ξ^* \bar{K}$ and $Ωη$ interaction within a chiral unitary approach,"In this work we study the interaction of the coupled channels $\Omega \eta$
and $\Xi^* \bar{K}$ within the chiral unitary approach. The systems under
consideration have total isospins $0$, strangeness $S = -3$, and spin $3/2$. We
studied the $s$ wave interaction which implies that the possible resonances
generated in the system can have spin-parity $J^P = 3/2^-$. The unitary
amplitudes in coupled channels develop poles that can be associated with some
known baryonic resonances. We find there is a dynamically generated $3/2^-$
$\Omega$ state with mass around $1800$ MeV, which is in agreement with the
predictions of the five-quark model.",1510.07419v2
2014-06-16,Fractionally charged skyrmions in fractional quantum Hall effect,"The fractional quantum Hall effect has inspired searches for exotic emergent
topological particles, such as fractionally charged excitations, composite
fermions, abelian and nonabelian anyons and Majorana fermions. Fractionally
charged skyrmions, which support both topological charge and topological
vortex-like spin structure, have also been predicted to occur in the vicinity
of 1/3 filling of the lowest Landau level. The fractional skyrmions, however,
are anticipated to be exceedingly fragile, suppressed by very small Zeeman
energies. Here we show that, slightly away from 1/3 filling, the smallest
manifestations of the fractional skyrmion exist in the excitation spectrum for
a broad range of Zeeman energies, and appear in resonant inelastic light
scattering experiments as well-defined resonances slightly below the long
wavelength spin wave mode. The spectroscopy of these exotic bound states serves
as a sensitive tool for investigating the residual interaction between
composite fermions, responsible for delicate new fractional quantum Hall states
in this filling factor region.",1406.4042v2
2019-12-13,Size Effect in Electron Paramagnetic Resonance Spectra of Impurity Centers in Diamond Nanoparticles,"The evolution of the polycrystalline pattern of electron paramagnetic
resonance (EPR) spectra of intrinsic and induced paramagnetic centers in an
ensemble of submicrometer diamond particles on diminishing average particle
size is considered. Recent experimental data unambiguously demonstrate
consistent reduction and then zeroing of typical hyperfine pattern from P1
centers on approaching a certain particle size and below it. These changes are
accompanied by appearance and strengthening of new structureless signals. In
small particles the electron wave function of a surface paramagnetic center is
delocalized over the whole nanoparticle. In result the electron spin
""experiences"" the average field of all surrounding nuclei, which is zero. At
the same time, the paramagnetic centers localized in the bulk of a nanoparticle
are also cut off the hyperfine interaction due to the electron spin diffusion.
Thus, upon the nanodiamond particle size decreases the hyperfine related
features of the polycrystalline EPR spectrum become weaker and the spectrum
appear to be structureless.",1912.06330v2
2021-12-13,Coupled Hubbard ladders at weak coupling: Pairing and spin excitations,"The Hubbard model provides a simple framework in which one can study how
certain aspects of the electronic structure of strongly interacting systems can
be tuned to optimize the superconducting pairing correlations and how these
changes affect the mechanisms giving rise to them. Here we use a weak-coupling
random phase approximation to study a two-dimensional Hubbard model with a
unidirectional modulation of the hopping amplitudes as the system evolves from
the uniform square lattice to an array of weakly coupled two-leg ladders. We
find that the pairing correlations retain their dominant $d_{x^2-y^2}$-wave
like structure and that they are significantly enhanced for a slightly
modulated lattice. This enhancement is traced backed to an increase in the
strength of the spin-fluctuation pairing interacting due to favorable Fermi
surface nesting in the modulated system. We then use a random-phase
approximation BCS framework to examine the evolution of the neutron resonance
in the superconducting state. We find that it changes only weakly for moderate
modulations, but breaks up into two distinct resonances at incommensurate
wave-vectors in the limit of weakly coupled ladders.",2112.06998v1
2022-05-23,Fully-charm and -bottom pentaquarks in a Lattice-QCD inspired quark model,"The fully-charm and -bottom pentaquarks, \emph{i.e.} $cccc\bar{c}$ and
$bbbb\bar{b}$, with spin-parity quantum numbers $J^P=\frac{1}{2}^-$,
$\frac{3}{2}^-$ and $\frac{5}{2}^-$, are investigated within a Lattice-QCD
inspired quark model, which has already successfully described the recently
announced fully-charm tetraquark candidate $X(6900)$, and has also predicted
several other fully-heavy tetraquarks. A powerful computational technique,
based on the Gaussian expansion method combined with a complex-scaling range
approach, is employed to predict, and distinguish, bound, resonance and
scattering states of the mentioned five-body system. Both baryon-meson and
diquark-diquark-antiquark configurations, along with all of their possible
color channels are comprehensively considered. Narrow resonances are obtained
in each spin-parity channel for the fully-charm and -bottom systems. Moreover,
most of them seems to be compact multiquarks whose wave-functions are dominated
by either hidden-color baryon-meson or diquark-diquark-antiquark structure, or
by the coupling between them.",2205.11548v1
1994-01-24,Theory of Spin-Split Cyclotron Resonance in the Extreme Quantum Limit,"We present an interpretation of recent cyclotron resonance experiments on the
two-dimensional electron gas in GaAs/AlGaAs heterostructures. We show that the
observed dependence of the resonance spectrum on Landau level occupancy and
temperature arises from the interplay of three factors: spin-splitting of the
cyclotron frequency; thermal population of the two spin states; and coupling of
the resonances for each spin orientation by Coulomb interactions. In addition,
we derive an $f$-sum rule which allows spin polarisation to be determined
directly from resonance spectra.",9401049v1
2020-02-10,Electron Spin Resonance spectroscopy with femtoliter detection volume,"We report electron spin resonance measurements of donors in silicon at
millikelvin temperatures using a superconducting $LC$ planar micro-resonator
and a Josephson Parametric Amplifier. The resonator includes a nanowire
inductor, defining a femtoliter detection volume. Due to strain in the
substrate, the donor resonance lines are heavily broadened. Single-spin to
photon coupling strengths up to $\sim 3~\text{kHz}$ are observed. The single
shot sensitivity is $120 \pm 24~$spins/Hahn echo, corresponding to $\approx 12
\pm 3$~spins$/\sqrt{\text{Hz}}$ for repeated acquisition.",2002.03669v1
2017-05-30,Communication and information processing in magnetic nanostructures with edge spin waves,"Low dissipation data processing with spins is one of the promising directions
for future information and communication technologies. Despite a signifcant
progress, the available magnonic devices are not broadband yet and have
restricted capabilities to redirect spin waves. Here we propose a breakthrough
approach to the spin wave manipulation in patterned magnetic nanostructures
with unmatched characteristics, which exploits spin waves analogous to edge
waves propagating along a water-wall boundary. Using theory, micromagnetic
simulations and experiment we investigate spin waves propagating along the
edges in magnetic structures, under an in-plane DC magnetic field inclined with
respect to the edge. The proposed edge spin waves overcome important challenges
faced by previous technologies such as the manipulation of the spin wave
propagation direction, and they substantially improve the capability of
transmitting information at frequencies exceeding 10 GHz. The concept of the
edge spin waves allows to design broad range of logic devices such as
splitters, interferometers, or edge spin wave transistors with unprecedented
characteristics and potentially strong impact on information technologies.",1705.10536v2
2006-05-12,Spin-Wave Theory of the Multiple-Spin Exchange Model on a Triangular Lattice in a Magnetic Field : 3-Sublattice Structures,"We study the spin wave in the S=1/2 multiple-spin exchange model on a
triangular lattice in a magnetic field within the linear spin-wave theory. We
take only two-, three- and four-spin exchange interactions into account and
restrict ourselves to the region where a coplanar three-sublattice state is the
mean-field ground state. We found that the Y-shape ground state survives
quantum fluctuations and the phase transition to a phase with a 6-sublattice
structure occurs with softening of the spin wave. We estimated the quantum
corrections to the ground state sublattice magnetizations due to zero-point
spin-wave fluctuations.",0605318v1
2005-10-31,Behavior of Torsional Alfven Waves and Field Line Resonance on Rotating Magnetars,"Torsional Alfven waves are likely excited with bursts in rotating magnetars.
These waves are probably propagated through corotating atmospheres toward a
vacuum exterior. We have studied the physical effects of the azimuthal wave
number and the characteristic height of the plasma medium on wave transmission.
In this work, explicit calculations were carried out based on the three-layered
cylindrical model. We found that the coupling strength between the internal
shear and the external Alfven modes is drastically enhanced, when resonance
occurs in the corotating plasma cavity. The spatial structure of the
electromagnetic fields in the resonance cavity is also investigated when Alfven
waves exhibit resonance.",0510842v1
2021-12-23,Nutation spin waves in ferromagnets,"Magnetization dynamics and spin waves in ferromagnets are investigated using
the inertial Landau-Lifshitz-Gilbert equation. Taking inertial magnetization
dynamics into account, dispersion relations describing the propagation of
nutation spin waves in an arbitrary direction relative to the applied magnetic
field are derived via Maxwell's equations. It is found that the inertia of
magnetization causes the hybridization of electromagnetic waves and nutation
spin waves in ferromagnets, hybrid nutation spin waves emerge, and the redshift
of frequencies of precession spin waves is initiated, which transforms to
precession-nutation spin waves. These effects depend sharply on the direction
of wave propagation relative to the applied magnetic field. Moreover, the waves
propagating parallel to the applied field are circularly polarized, while the
waves propagating perpendicular to that field are elliptically polarized. The
characteristics of these spin nutation waves are also analyzed.",2112.12503v3
2018-05-21,Tunable spinful matter wave valve,"We investigate the transport problem that a spinful matter wave is incident
on a strong localized spin-orbit-coupled Bose-Einstein condensate in optical
lattices, where the localization is admitted by atom interaction only existing
at one particular site, and the spin-orbit coupling arouse spatial rotation of
the spin texture. We find that tuning the spin orientation of the localized
Bose-Einstein condensate can lead to spin-nonreciprocal / spin-reciprocal
transport, meaning the transport properties are dependent on / independent of
the spin orientation of incident waves. In the former case, we obtain the
conditions to achieve transparency, beam-splitting, and blockade of the
incident wave with a given spin orientation, and furthermore the ones to
perfectly isolate incident waves of different spin orientation, while in the
latter, we obtain the condition to maximize the conversion of different spin
states. The result may be useful to develop a novel spinful matter wave valve
that integrates spin switcher, beam-splitter, isolator, and converter. The
method can also be applied to other real systems, e.g., realizing perfect
isolation of spin states in magnetism, which is otherwise rather difficult.",1805.08129v1
2005-02-28,Structural matters in HTSC; the origin and form of stripe organization and checker boarding,"The paper deals with the controversial charge and spin self-organization
phenomena in the HTSC cuprates, of which neutron, X-ray, STM and ARPES
experiments give complementary, sometimes apparently contradictory glimpses.
The examination has been set in the context of the boson-fermion, negative-U
understanding of HTSC advocated over many years by the author. Stripe models
are developed which are 2q in nature and diagonal in form. For such a geometry
to be compatible with the data rests upon both the spin and charge arrays being
face-centred. Various special doping concentrations are closely looked at, in
particular p = 0.1836 or 9/49, which is associated with the maximization of the
superconducting condensation energy and the termination of the pseudogap
regime. The stripe models are dictated by real space organization of the holes,
whereas the dispersionless checkerboarding is interpreted in terms of
correlation driven collapse of normal Fermi surface behaviour and response
functions. The incommensurate spin diffraction below the resonance energy is
seen as in no way expressing spin-wave physics or Fermi surface nesting, but is
driven by charge and strain (Jahn-Teller) considerations, and it stands
virtually without dispersion. The apparent dispersion comes from the downward
dispersion of the resonance peak, and the growth of a further incoherent
commensurate peak ensuing from the falling level of charge stripe organization
under excitation.",0502666v1
2007-05-02,Magnetic Excitations in La2CuO4 probed by Indirect Resonant Inelastic X-ray Scattering,"Recent experiments on La$_2$CuO$_4$ suggest that indirect resonant inelastic
X-ray scattering (RIXS) might provide a probe for transversal spin dynamics. We
present in detail a systematic expansion of the relevant magnetic RIXS cross
section by using the ultrashort core-hole lifetime (UCL) approximation. We
compute the scattering intensity and its momentum dependence in leading order
of the UCL expansion. The scattering is due to two-magnon processes and is
calculated within a linear spin-wave expansion of the Heisenberg spin model for
this compound, including longer range and cyclic spin interactions. We observe
that the latter terms in the Hamiltonian enhance the first moment of the
spectrum if they strengthen the antiferromagnetic ordering. The theoretical
spectra agree very well with experimental data, including the observation that
scattering intensity vanishes for the transferred momenta ${\bf q} = (0,0)$ and
${\bf q} = (\pi,\pi)$. We show that at finite temperature there is an
additional single-magnon contribution to the scattering with a spectral weight
proportional to $T^3$. We also compute the leading corrections to the UCL
approximation and find them to be small, putting the UCL results on a solid
basis. All this univocally points to the conclusion that the observed low
temperature RIXS intensity in La$_2$CuO$_4$ is due to two-magnon scattering.",0705.0263v4
2019-01-14,Helical Ordering of Spin Trimers in a Distorted Kagome Lattice of Gd$_3$Ru$_4$Al$_{12}$ Studied by Resonant X-ray Diffraction,"Successive magnetic phase transitions at $T_1$=17.5 K and $T_2$=18.5 K in
Gd$_3$Ru$_4$Al$_{12}$, with a distorted kagome lattice of Gd ions, is studied
using resonant X-ray diffraction with polarization analysis. It has been
suggested that in this compound the $S=7/2$ spins on the nearest-neighbor
Gd-triangle form a ferromagnetic trimer and the Gd lattice can be effectively
considered as an antiferromagnetic triangular lattice of $S=21/2$ spin trimers
[S. Nakamura et al., Phys. Rev. B 98, 054410 (2018)]. We show that the magnetic
order in this system is described by an incommensurate wave vector $q$~(0.27,
0, 0), which varies slightly with temperature. In the low temperature phase
below $T_1$, the experimental results are well explained by considering that
the spin trimers form a helical order with both the $c$-axis and $c$-plane
components. In the intermediate phase above $T_1$, the $c$-axis component
vanishes, resulting in a sinusoical structure within the $c$-plane. The
sinusoidal-helical transition at $T_1$ can be regarded as an ordering of chiral
degree of freedom, which is degenerate in the intermediate phase.",1901.04231v1
2019-08-09,Experimental Demonstration of an Extreme Sub-Wavelength Nanomagnetic Acoustic Antenna Actuated by Spin-Orbit Torque from a Heavy Metal Nanostrip,"A novel on-chip extreme sub-wavelength ""acoustic antenna"" whose radiation
efficiency is ~50 times larger than the theoretical limit for a resonantly
driven antenna is demonstrated. The antenna is composed of magnetostrictive
nanomagnets deposited on a piezoelectric substrate. The nanomagnets are
partially in contact with a heavy metal (Pt) nanostrip. Passage of alternating
current through the nanostrip exerts alternating spin-orbit torque on the
nanomagnets and periodically rotates their magnetizations. During the rotation,
the magnetostrictive nanomagnets expand and contract, thereby setting up
alternating tensile and compressive strain in the piezoelectric substrate
underneath. This leads to the generation of a surface acoustic wave in the
substrate and makes the nanomagnet assembly act as an acoustic antenna. The
measured radiation efficiency of this acoustic antenna at the detected
frequency is ~1%, while the wavelength to antenna dimension ratio is ~ 67:1.
For a standard antenna driven at acoustic resonance, the efficiency would have
been limited to ~ (1/67)^2 = 0.02%. It was possible to beat that limit (by ~50
times) via actuating the antenna not by acoustic resonance, but by using a
completely different mechanism involving spin-orbit torque originating from the
giant spin Hall effect in Pt.",1908.03516v2
2023-06-27,Laser induced surface magnetization in Floquet-Weyl semimetals,"We investigate optically induced magnetization in Floquet-Weyl semimetals
generated by irradiation of a circularly-polarized continuous-wave laser from
the group II-V narrow gap semiconductor Zn$_3$As$_2$ in a theoretical manner.
Here, this trivial and nonmagnetic crystal is driven by the laser with a nearly
resonant frequency with a band gap to generate two types of Floquet-Weyl
semimetal phases composed of different spin states. These two phases host
nontrivial two-dimensional surface states pinned to the respective pairs of the
Weyl points. By numerically evaluating the laser-induced transient
carrier-dynamics, it is found that both spins are distributed in an uneven
manner on the corresponding surface states due to significantly different
excitation probabilities caused by the circularly-polarized laser with the
nearly resonant frequency. It is likely that such spin-polarized surface states
produce surface magnetization, and furthermore the inverse Faraday effect also
contributes almost as much as the spin magnetization. To be more specific,
excited carries with high density of the order of $10^{21}\: {\rm cm}^{-3}$ are
generated by the laser with electric field strength of a few MV/cm to result in
the surface magnetization that becomes asymptotically constant with respect to
time, around 1 mT. The magnitude and the direction of it depend sharply on both
of the intensity and frequency of the driving laser, which would be detected by
virtue of the magneto-optic Kerr effect.",2306.15522v2
2023-09-07,Hyperpolarisation of nuclear spins: polarisation blockade,"Efficient hyperpolarisation of nuclear spins via optically active defect
centers, such as the nitrogen vacancy (NV) center in diamond, has great
potential for enhancing NMR based quantum information processing and nanoscale
magnetic resonance imaging. Recently, pulse-based protocols have been shown to
efficiently transfer optically induced polarisation of the electron defect spin
to surrounding nuclear spins -- at particular resonant pulse intervals. In this
work, we investigate the performance of these protocols, both analytically and
experimentally, with the electronic spin of a single NV defect. We find that
whenever polarisation resonances of nuclear spins are near-degenerate with a
`blocking' spin, which is single spin with stronger off-diagonal coupling to
the electronic central spin, they are displaced out of the central resonant
region -- without, in general, significant weakening of the resonance. We
analyse the underlying physical mechanism and obtain a closed form expression
for the displacement. We propose that spin blocking represents a common but
overlooked effect in hyperpolarisation of nuclear spins and suggest solutions
for improved protocol performance in the presence of (naturally occurring)
blocking nuclear spins.",2309.03761v1
2005-11-21,Excitation of spin waves by spin polarized current,"Numerical and analytical analysis is used to explain recently observed
experimental phenomenon - excitation of spin waves in spin valves due to the
applied spin polarized current. Excited spin waves are being identified and
  Lyapunov stability analysis is being used to identify different regions of
stability depending on the value of the applied current.",0511503v2
2020-07-22,An Electromagnetic Approach to Cavity Spintronics,"The fields of cavity quantum electrodynamics and magnetism have recently
merged into \textit{`cavity spintronics'}, investigating a quasiparticle that
emerges from the strong coupling between standing electromagnetic waves
confined in a microwave cavity resonator and the quanta of spin waves, magnons.
This phenomenon is now expected to be employed in a variety of devices for
applications ranging from quantum communication to dark matter detection. To be
successful, most of these applications require a vast control of the coupling
strength, resulting in intensive efforts to understanding coupling by a variety
of different approaches. Here, the electromagnetic properties of both resonator
and magnetic samples are investigated to provide a comprehensive understanding
of the coupling between these two systems. Because the coupling is a
consequence of the excitation vector fields, which directly interact with
magnetisation dynamics, a highly-accurate electromagnetic perturbation theory
is employed which allows for predicting the resonant hybrid mode frequencies
for any field configuration within the cavity resonator, without any fitting
parameters. The coupling is shown to be strongly dependent not only on the
excitation vector fields and sample's magnetic properties but also on the
sample's shape. These findings are illustrated by applying the theoretical
framework to two distinct experiments: a magnetic sphere placed in a
three-dimensional resonator, and a rectangular, magnetic prism placed on a
two-dimensional resonator. The theory provides comprehensive understanding of
the overall behaviour of strongly coupled systems and it can be easily modified
for a variety of other systems.",2007.11483v2
2020-10-22,Spin-Orbit Misalignments in Tertiary-Induced Black-Hole Binary Mergers: Theoretical Analysis,"Black-hole (BH) binary mergers driven by gravitational perturbations of
tertiary companions constitute an important class of dynamical formation
channels for compact binaries detected by LIGO/VIRGO. Recent works have
examined numerically the combined orbital and spin dynamics of BH binaries that
undergo large Lidov-Kozai (LK) eccentricity oscillations induced by a highly
inclined companion and merge via gravitational wave radiation. However, the
extreme eccentricity variations make such systems difficult to characterize
analytically. In this paper, we develop an analytical formalism for
understanding the spin dynamics of binary BHs undergoing LK-induced mergers. We
show that, under certain conditions, the eccentricity oscillations of the
binary can be averaged over to determine the long-term behavior of the BH spin
in a smooth way. In particular, we demonstrate that the final spin-orbit
misalignment angle $\theta_{\rm sl}$ is often related to the binary's
primordial spin orientation through an approximate adiabatic invariant. Our
theory explains the ""$90^\circ$ attractor"" (as found in recent numerical
studies) for the evolution of $\theta_{\rm sl}$ when the initial BH spin is
aligned with the orbital axis and the octupole LK effects are negligible --
such a ""$90^\circ$ attractor"" would lead to a small binary effective spin
parameter $\chi_{\rm eff}\sim 0$ even for large intrinsic BH spins. We
calculate the deviation from adiabaticity in closed form as a function of the
initial conditions. We also place accurate constraints on when this adiabatic
invariant breaks down due to resonant spin-orbit interactions. We consider both
stellar-mass and supermassive BH tertiary companions, and provide simple
prescriptions for determining analytically the final spin-orbit misalignment
angles of the merging BH binaries.",2010.11951v2
2016-08-07,Spin-orbit coupling in Fe-based superconductors,"We study the spin resonance peak in recently discovered iron-based
superconductors. The resonance peak observed in inelastic neutron scattering
experiments agrees well with predicted results for the extended $s$-wave
($s_\pm$) gap symmetry. Recent neutron scattering measurements show that there
is a disparity between longitudinal and transverse components of the dynamical
spin susceptibility. Such breaking of the spin-rotational invariance in the
spin-liquid phase can occur due to spin-orbit coupling. We study the role of
the spin-orbit interaction in the multiorbital model for Fe-pnictides and show
how it affects the spin resonance feature.",1608.02230v1
2020-11-19,Coupling spins to nanomechanical resonators: Toward quantum spin-mechanics,"Spin-mechanics studies interactions between spin systems and mechanical
vibrations in a nanomechanical resonator and explores their potential
applications in quantum information processing. In this tutorial, we summarize
various types of spin-mechanical resonators and discuss both the
cavity-QED-like and the trapped-ion-like spin-mechanical coupling processes.
The implementation of these processes using negatively charged nitrogen vacancy
and silicon vacancy centers in diamond is reviewed. Prospects for reaching the
full quantum regime of spin-mechanics, in which quantum control can occur at
the level of both single spin and single phonon, are discussed with an emphasis
on the crucial role of strain coupling to the orbital degrees of freedom of the
defect centers.",2011.09990v1
2004-12-30,Nanomagnetic Planar Magnetic Resonance Microscopy Lens,"The achievement of three-dimensional atomic resolution magnetic resonance
microscopy remains one of the main challenges in the visualization of
biological molecules. The prospects for single spin microscopy have come
tantalizingly close due to the recent developments in sensitive
instrumentation. Despite the single spin detection capability in systems of
spatially well-isolated spins, the challenge that remains is the creation of
conditions in space where only a single spin is resonant and detected in the
presence of other spins in its natural dense spin environment. We present a
nanomagnetic planar design where a localized Angstrom-scale point in
three-dimensional space is created above the nanostructure with a non-zero
minimum of the magnetic field magnitude. The design thereby represents a
magnetic resonance microscopy lens where potentially only a single spin located
in the focus spot of the structure is resonant. Despite the presence of other
spins in the Angstrom-scale vicinity of the resonant spin, the high gradient
magnetic field of the lens renders those spins inactive in the detection
process.",0412217v1
2019-06-20,Effects of spin-orbit coupling on the neutron spin resonance in iron-based superconductors,"The so-called neutron spin resonance consists of a prominent enhancement of
the magnetic response at a particular energy and momentum transfer upon
entering the superconducting state of unconventional superconductors. In the
case of iron-based superconductors, the neutron resonance has been extensively
studied experimentally, and a peculiar spin-space anisotropy has been
identified by polarized inelastic neutron scattering experiments. Here we
perform a theoretical study of the energy- and spin-resolved magnetic
susceptibility in the superconducting state with $ s_{+-} $-wave order
parameter, relevant to iron-pnictide and iron-chalcogenide superconductors. Our
model is based on a realistic bandstructure including spin-orbit coupling with
electronic Hubbard-Hund interactions included at the RPA level. Spin-orbit
coupling is taken into account both in the generation of spin-fluctuation
mediated pairing, as well as the numerical computation of the spin
susceptibility in the superconducting state. We find that spin-orbit coupling
and superconductivity in conjunction can reproduce the salient experimentally
observed features of the magnetic anisotropy of the neutron resonance. This
includes the possibility of a double resonance, the tendency for a $c$-axis
polarized resonance, and the existence of enhanced magnetic anisotropy upon
entering the superconducting phase.",1906.08566v1
2020-08-04,Resonant spin amplification meets electron spin resonance in $n$-GaAs,"Periodic excitation of electron spin polarization by consecutive laser pulses
in phase with Larmor spin precession about a magnetic field results in resonant
spin amplification (RSA). We observe a drastic modification of RSA in $n$-doped
bulk GaAs under the influence of external oscillating magnetic field. We find a
double-peaked electron spin resonance instead of a single-peaked resonance
expected without optical pumping. The frequency splitting increases linearly
with amplitude of field oscillations, while the spin deviation increases
quadratically. Moreover, we show that the oscillating field can both
significantly suppress RSA and induce new conditions for resonance. Using
quaternions to describe spin rotations, we develop a theory that simultaneously
considers spin precession, decay, and amplification and reproduces the entire
set of the experimental data. Using the radio-frequency field allows one to
control the conditions of RSA and achieve fine tuning of average spin
polarization without modifying the parameters of optical pumping.",2008.01626v1
2022-07-26,The effects of nonlinearities on tidal flows in the convective envelopes of rotating stars and planets in exoplanetary systems,"In close exoplanetary systems, tidal interactions drive orbital and spin
evolution of planets and stars over long timescales. Tidally-forced inertial
waves (restored by the Coriolis acceleration) in the convective envelopes of
low-mass stars and giant gaseous planets contribute greatly to the tidal
dissipation when they are excited and subsequently damped (e.g. through viscous
friction), especially early in the life of a system. These waves are known to
be subject to nonlinear effects, including triggering differential rotation in
the form of zonal flows. In this study, we use a realistic tidal body forcing
to excite inertial waves through the residual action of the equilibrium tide in
the momentum equation for the waves. By performing 3D nonlinear hydrodynamical
simulations in adiabatic and incompressible convective shells, we investigate
how the addition of nonlinear terms affects the tidal flow properties, and the
energy and angular momentum redistribution. In particular, we identify and
justify the removal of terms responsible for unphysical angular momentum
evolution observed in a previous numerical study. Within our new set-up, we
observe the establishment of strong cylindrically-sheared zonal flows, which
modify the tidal dissipation rates from prior linear theoretical predictions.
We demonstrate that the effects of this differential rotation on the waves
neatly explains the discrepancies between linear and nonlinear dissipation
rates in many of our simulations. We also highlight the major role of both
corotation resonances and parametric instabilities of inertial waves, which are
observed for sufficiently high tidal forcing amplitudes or low viscosities, in
affecting the tidal flow response.",2207.12780v1
2014-09-18,Spin-transfer torque induced spin waves in antiferromagnetic insulators,"We explore the possibility of exciting spin waves in insulating
antiferromagnetic films by injecting spin current at the surface. We analyze
both magnetically compensated and uncompensated interfaces. We find that the
spin current induced spin-transfer torque can excite spin waves in insulating
antiferromagnetic materials and that the chirality of the excited spin wave is
determined by the polarization of the injected spin current. Furthermore, the
presence of magnetic surface anisotropy can greatly increase the accessibility
of these excitations.",1409.5460v2
2011-07-28,Identification and selection rules of the spin-wave eigen-modes in a normally magnetized nano-pillar,"We report on a spectroscopic study of the spin-wave eigen-modes inside an
individual normally magnetized two layers circular nano-pillar
(Permalloy$|$Copper$|$Permalloy) by means of a Magnetic Resonance Force
Microscope (MRFM). We demonstrate that the observed spin-wave spectrum
critically depends on the method of excitation. While the spatially uniform
radio-frequency (RF) magnetic field excites only the axially symmetric modes
having azimuthal index $\ell=0$, the RF current flowing through the
nano-pillar, creating a circular RF Oersted field, excites only the modes
having azimuthal index $\ell=+1$. Breaking the axial symmetry of the
nano-pillar, either by tilting the bias magnetic field or by making the pillar
shape elliptical, mixes different $\ell$-index symmetries, which can be excited
simultaneously by the RF current. Experimental spectra are compared to
theoretical prediction using both analytical and numerical calculations. An
analysis of the influence of the static and dynamic dipolar coupling between
the nano-pillar magnetic layers on the mode spectrum is performed.",1107.5699v2
2017-07-16,A Monolithic Topologically Protected Phononic Circuit,"Precise control of elastic waves in modes and coherences is of great use in
reinforcing nowadays elastic energy harvesting/storage, nondestructive testing,
wave-mater interaction, high sensitivity sensing and information processing,
etc. All these implementations are expected to have elastic transmission with
lower transmission losses and higher degree of freedom in transmission path.
Inspired by topological states of quantum matters, especially quantum spin Hall
effects (QSHEs) providing passive solutions of unique disorder-immune surface
states protected by underlying nontrivial topological invariants of the bulk,
thus solving severe performance trade-offs in experimentally realizable
topologically ordered states. Here, we demonstrate experimentally the first
elastic analogue of QSHE, by a concise phononic crystal plate with only
perforated holes. Strong elastic spin-orbit coupling is realized accompanied by
the first topologically-protected phononic circuits with both robustness and
negligible propagation loss overcoming many circuit- and system-level
performance limits induced by scattering. This elegant approach in a monolithic
substrate opens up the possibility of realizing topological materials for
phonons in both static and time-dependent regimes, can be immediately applied
to multifarious chip-scale devices with both topological protection and massive
integration, such as on-chip elastic wave-guiding, elastic splitter, elastic
resonator with high quality factor, and even (pseudo-)spin filter.",1707.04901v1
2019-07-05,Tunability of domain structure and magnonic spectra in antidot arrays of Heusler alloy,"Materials suitable for magnonic crystals demand low magnetic damping and long
spin wave (SW) propagation distance. In this context Co based Heusler compounds
are ideal candidates for magnonic based applications. In this work, antidot
arrays (with different shapes) of epitaxial
$\mathrm{Co}_2\mathrm{Fe}_{0.4}\mathrm{Mn}_{0.6}\mathrm{Si}$ (CFMS) Heusler
alloy thin films have been prepared using e-beam lithography and sputtering
technique. Magneto-optic Kerr effect and ferromagnetic resonance analysis have
confirmed the presence of dominant cubic and moderate uniaxial magnetic
anisotropies in the thin films. Domain imaging via x-ray photoemission electron
microscopy on the antidot arrays reveals chain like switching or correlated
bigger domains for different shape of the antidots. Time-resolved MOKE
microscopy has been performed to study the precessional dynamics and magnonic
modes of the antidots with different shapes. We show that the optically induced
spin-wave spectra in such antidot arrays can be tuned by changing the shape of
the holes. The variation in internal field profiles, pinning energy barrier,
and anisotropy modifies the spin-wave spectra dramatically within the antidot
arrays with different shapes. We further show that by combining the
magnetocrystalline anisotropy with the shape anisotropy, an extra degree of
freedom can be achieved to control the magnonic modes in such antidot lattices.",1907.02746v1
2024-02-15,Standing spin waves in Permalloy-NiO bilayers as a probe of the interfacial exchange coupling,"Ferromagnetic/Antiferromagnetic (FM/AFM) bilayers dynamics have been a recent
topic of interest due to the interaction occurring at the interface, where the
magnetic moments of the AFM can be imprinted into the FM, and the exchange bias
field can affect these dynamics. Here, we investigate Permalloy (Py) and NiO
(Py/NiO) hybrids and for comparison single Py films in the broad Py thickness
range varied from few nm to 200 nm by using static (Kerr effect) and dynamic
(spin waves) measurements along with micromagnetic simulations. We observe
hybrid modes between uniform (ferromagnetic resonance FMR, n=0) and
perpendicular standing spin waves (PSSWs, n=1, 2) and a clear enhancement of
the PSSWs modes frequencies upon interfacing Py with NiO both from experiments
and simulations. This enhancement becomes less pronounced as the thickness of
the film increases, demonstrating its interfacial origin rooted in the exchange
coupling between the FM and AFM layers. Besides, through micromagnetic
simulations, we investigate and correlate changes in spatial profiles of the
PSSWs with the interfacial exchange coupling. As the thickness is increased, we
see that the n=1 and n=2 modes begin to couple with the fundamental FMR mode,
resulting in asymmetric (with respect the Py layer center) modes. Our results
suggest that PSSWs detection in a ferromagnet offers a means of probing the
interfacial exchange coupling with the adjacent AFM layer. Furthermore, the
controlled spatial symmetry breaking by the AFM layer enables engineering of
PSSWs with different spatial profiles in the FM.",2402.10292v1
2017-10-23,Frequency and wavenumber selective excitation of spin waves through coherent energy transfer from elastic waves,"Using spin-wave tomography (SWaT), we have investigated the excitation and
the propagation dynamics of optically-excited magnetoelastic waves, i.e.
hybridized modes of spin waves and elastic waves, in a garnet film. By using
time-resolved SWaT, we reveal the excitation dynamics of magnetoelastic waves
through coherent-energy transfer between optically-excited pure-elastic waves
and spin waves via magnetoelastic coupling. This process realizes frequency and
wavenumber selective excitation of spin waves at the crossing of the dispersion
relations of spin waves and elastic waves. Finally, we demonstrate that the
excitation mechanism of the optically-excited pure-elastic waves, which are the
source of the observed magnetoelastic waves, is dissipative in nature.",1710.08087v2
2019-09-11,Tunable group delay in a doubly resonant metasurface composed of two dissimilar split-ring resonators,"We develop a method to control the group delay of electromagnetic waves
continuously using a doubly resonant metasurface. The method is based on the
dependences of i) the group velocity in a medium featuring two resonance lines
on the resonance linewidths and ii) the resonance linewidth of a metasurface
composed of split-ring resonators on an incidence angle of electromagnetic
wave. To verify this method for group-delay control, we design a terahertz
metasurface composed of two split-ring resonators with different resonance
frequencies and numerically analyze the transmission characteristic of the
metasurface. Double resonance lines are observed for oblique incidence and the
resonance transmission dips become deeper and broader with increasing the
incidence angle. The group delay at around the center frequency of the double
resonance lines is found to vary in the range about from 0s to 20 times the
period of the incident wave with the incidence angle. In contrast with a
previously reported method for variable control of group delay using
electromagnetically-induced-transparency-like metamaterials, a high
transmittance is achieved for a small group delay condition.",1909.04833v1
2019-12-05,Spin pumping into a spin glass material,"Spin pumping is a recently established means for generating a pure spin
current, whereby spins are pumped from a magnet into the adjacent target
material under the ferromagnetic resonance condition. We theoretically
investigate the spin pumping from an insulating ferromagnet into spin glass
materials. Combining a dynamic theory of spin glasses with the linear-response
formulation of the spin pumping, we calculate temperature dependence of the
spin pumping near the spin glass transition. The analysis predicts that a
characteristic peak appears in the spin pumping signal, reflecting that the
spin fluctuations slow down upon the onset of spin freezing.",1912.02337v2
2010-05-30,On the homotopy multiple-variable method and its applications in the interactions of nonlinear gravity waves,"The basic ideas of a homotopy-based multiple-variable method is proposed and
applied to investigate the nonlinear interactions of periodic traveling waves.
Mathematically, this method does not depend upon any small physical parameters
at all and thus is more general than the traditional multiple-scale
perturbation techniques. Physically, it is found that, for a fully developed
wave system, the amplitudes of all wave components are finite even if the wave
resonance condition given by Phillips (1960) is exactly satisfied. Besides, it
is revealed that there exist multiple resonant waves, and that the amplitudes
of resonant wave may be much smaller than those of primary waves so that the
resonant waves sometimes contain rather small part of wave energy. Furthermore,
a wave resonance condition for arbitrary numbers of traveling waves with large
wave amplitudes is given, which logically contains Phillips' four-wave
resonance condition but opens a way to investigate the strongly nonlinear
interaction of more than four traveling waves with large amplitudes. This work
also illustrates that the homotopy multiple-variable method is helpful to gain
solutions with important physical meanings of nonlinear problems, if the
multiple variables are properly defined with clear physical meanings.",1005.5539v2
2016-08-05,Seismic metasurfaces: Sub-wavelength resonators and Rayleigh wave interaction,"We consider the canonical problem of an array of rods, which act as
resonators, placed on an elastic substrate; the substrate being either a thin
elastic plate or an elastic half-space. In both cases the flexural plate, or
Rayleigh surface, waves in the substrate interact with the resonators to create
interesting effects such as effective band-gaps for surface waves or filters
that transform surface waves into bulk waves; these effects have parallels in
the field of optics where such sub-wavelength resonators create metamaterials,
and metasurfaces, in the bulk and at the surface respectively.
  Here we carefully analyse this canonical problem by extracting the dispersion
relations analytically thereby examining the influence of both the flexural and
compressional resonances on the propagating wave. For an array of resonators
atop an elastic half-space we augment the analysis with numerical simulations.
Amongst other effects, we demonstrate the striking effect of a dispersion curve
that transitions from Rayleigh wave-like to shear wave-like behaviour and the
resultant change in displacement from surface to bulk waves.",1608.01792v1
2023-10-30,Dynamical renormalisation of a spin Hamiltonian via high-order nonlinear magnonics,"The macroscopic magnetic order in the ground state of solids is determined by
the spin-dependent Hamiltonian of the system. In the absence of external
magnetic fields, this Hamiltonian contains the exchange interaction, which is
of electrostatic origin, and the spin-orbit coupling, whose magnitude depends
on the atomic charge. Spin-wave theory provides a representation of the entire
spectrum of collective magnetic excitations, called magnons, assuming the
interactions to be constant and the number of magnons in the system negligible.
However, the electric field component of light is able to perturb electrostatic
interactions, charge distributions and, at the same time, can create a magnon
population. A fundamental open question therefore concerns the possibility to
optically renormalise the spin Hamiltonian. Here, we test this hypothesis by
using femtosecond laser pulses to resonantly pump electric-dipole-active pairs
of high-energy magnons near the edges of the Brillouin zone. The transient spin
dynamics reveals the activation and a surprising amplification of coherent
low-energy zone-centre magnons, which are not directly driven. Strikingly, the
spectrum of these low-energy magnons differs from the one observed in thermal
equilibrium, the latter being consistent with spin-wave theory. The light-spin
interaction thus results in a room-temperature renormalisation of the magnetic
Hamiltonian, with an estimated modification of the magnetic interactions by 10%
of their ground-state values. We rationalise the observation in terms of a
novel resonant scattering mechanism, in which zone-edge magnons couple
nonlinearly to the zone-centre modes. In a quantum mechanical model, we
analytically derive the corrections to the spectrum due to the photo-induced
magnon population, which are consistent with our experiments. Our results
present a milestone for an all-optical engineering of Hamiltonians.",2310.19667v1
2007-02-19,Tidal dissipation in rotating solar-type stars,"We calculate the excitation and dissipation of low-frequency tidal
oscillations in uniformly rotating solar-type stars. For tidal frequencies
smaller than twice the spin frequency, inertial waves are excited in the
convective envelope and are dissipated by turbulent viscosity. Enhanced
dissipation occurs over the entire frequency range rather than in a series of
very narrow resonant peaks, and is relatively insensitive to the effective
viscosity. Hough waves are excited at the base of the convective zone and
propagate into the radiative interior. We calculate the associated dissipation
rate under the assumption that they do not reflect coherently from the center
of the star. Tidal dissipation in a model based on the present Sun is
significantly enhanced through the inclusion of the Coriolis force but may
still fall short of that required to explain the circularization of close
binary stars. However, the dependence of the results on the spin frequency,
tidal frequency, and stellar model indicate that a more detailed evolutionary
study including inertial and Hough waves is required. We also discuss the case
of higher tidal frequencies appropriate to stars with very close planetary
companions. The survival of even the closest hot Jupiters can be plausibly
explained provided that the Hough waves they generate are not damped at the
center of the star. We argue that this is the case because the tide excited by
a hot Jupiter in the present Sun would marginally fail to achieve nonlinearity.
As conditions at the center of the star evolve, nonlinearity may set in at a
critical age, resulting in a relatively rapid inspiral of the hot Jupiter.",0702492v1
2014-08-05,Four-quark structure of the excited states of heavy mesons,"We propose a four-quark structure for some of the excited states of heavy
mesons containing a single charm or bottom quark. The four-quark wave functions
are constructed based on a diquark-antidiquark form under the constraint that
they form an antitriplet $\bar{\bf{3}}_f$ in $\mbox{SU(3)}_f$, which seems to
be realized in some of the excited states listed in Particle Data Group.
Depending on the structure of antidiquark, we construct two possible models for
its wave functions: Model I) the antidiquark is symmetric in flavor
($\bar{\bf{6}}_f$) and antisymmetric in color ($\bf{3}_c$) and Model II) the
antidiquark is antisymmetric in flavor ($\bf{3}_f$) and symmetric in color
($\bar{\bf{6}}_c$). To test phenomenological relevance of these wave functions,
we calculate the mass differences among the excited states of spin $J=0,1,2$
using color-spin interactions. The four-quark wave functions based on Model~I
is found to reproduce the observed mass of the excited states of heavy mesons.
Also, our four-quark model provides an interesting phenomenology relating to
the decay widths of the excited states. To further pursue the possibility of
the four-quark structure, we make a few predictions for open charm and open
bottom states that may be discovered in future experiments. Most of them are
expected to have broad widths, which would make them difficult to be identified
experimentally. However, one resonance with $J=1$ containing bottom and strange
quarks is expected to appear as a sharp peak with its mass around $B^{\bar
s}_{1N} \sim 5753$~MeV. Confirmation of the existence of such states in future
experiments will shed light on our understanding of the structure of heavy
meson excited states.",1408.1139v1
2023-05-15,Scattering of magnetostatic surface modes of ferromagnetic films by geometric defects,"Magnonics, an emerging field of Magnetism, studies spin waves (SWs) in
nano-structures, with an aim towards possible applications. As information may
be eventually transmitted with efficiency stored in the phase and amplitude of
spin waves, a topic of interest within Magnonics is the propagation of SW
modes. Thus, understanding mechanisms that may influence SW propagation is of
interest. Here the effect of localized surface geometric defects on
magnetostatic surface modes propagation is studied in ferromagnetic films and
semi-infinite media. Theoretical results are developed that allow to calculate
the scattering of these surface or Damon-Eshbach (DE) modes. A Green-Extinction
theorem is used to determine the scattering of incident surface modes, through
the determination of phase shifts of associated modes that are symmetric and
anti-symmetric under inversion in the same geometry with geometric defects.
Choosing localized symmetric depressions as geometric defects, scattering
transmission coefficients are determined that show perfect transmission at
specific frequencies or wave-lengths, that we associate with resonances in the
system. Interestingly the system shows the appearance of localized modes in the
depression regions, with associated discrete frequencies immersed in the
continuum spectrum of these surface DE modes. These localized modes have a
short wave-length content, and appear similarly in semi-infinite surfaces with
depressions. The latter indicates that these types of scattering effects should
appear in all surfaces with roughness or more pronounced geometric defects.",2305.08749v1
2007-06-08,Measuring the spin polarization and Zeeman energy of a spin-polarized electron gas: Comparison between Raman scattering and photoluminescence,"We compare resonant electronic Raman scattering and photoluminescence
measurements for the characterization of a spin-polarized two-dimensional
electron gas embedded in $\text{Cd}_{1-x}\text{Mn}_x\text{Te}$ single quantum
wells. From Raman scattering by single-particle excitations in a zero magnetic
field, we measure the Fermi velocity and then obtain the Fermi energy (as well
as the electron density), which is comparable to that extracted from
photoluminescence for moderate electron densities, assuming a bare band-edge
mass. At large electron densities, the Fermi energies derived from Raman
scattering and photoluminescence differ. For an applied in-plane magnetic field
and zero wave vector transferred to the electron gas, Raman scattering spectra
show peaks at both the Zeeman energy $Z$, resulting from collective excitations
of the spin-polarized electron gas, and the one electron spin-flip energy
$Z^*$. Magneto-photoluminescence spectra show conduction band splitting that
are equivalent to $Z$, suggesting that collective effects are present in the
photoluminescence spectra. Assuming (as before) an uncorrected mass, the degree
of spin polarization $\zeta$ determined from the magneto-photoluminescence
lineshape is found to differ from that derived from the magnetic field
dependent Raman scattering measurements for large electron densities. We
attribute the discrepancy in measuring $\zeta$ and the Fermi energy to the
renormalized mass resulting from many-body electron-electron interactions.",0706.1255v1
2012-10-30,Large Stark Effect for Li Donor Spins in Si,"We study the effect of a static electric field on lithium donor spins in
silicon. The anisotropy of the effective mass leads to the anisotropy of the
quadratic Stark susceptibility, which we determined using the Dalgarno-Lewis
exact summation method. The theory is asymptotically exact in the field domain
below Li-donor ionization threshold, relevant to the Stark-tuning electron spin
resonance experiments. To obtain the generalized Stark susceptibilities at
arbitrary fields, we propose a new variational wave function which reproduces
the exact results in the low-field limit. With the calculated susceptibilities
at hand, we are able to predict and analyze several important physical effects.
First, we observe that the energy level shifts due to the quadratic Stark
effect for Li donors in Si are equivalent to, and can be mapped onto, those
produced by an external stress.
  Second, we demonstrate that the Stark effect anisotropy, combined with the
unique valley-orbit splitting of a Li donor in Si, spin-orbit interaction and
specially tuned external stress, may lead to a very strong modulation of the
donor spin $g$-factor by the electric field. Third, we investigate the
influence of random strains on the $g$-factor shifts and quantify the random
strain limits and requirements to Si material purity necessary to observe the
$g$-factor Stark shifts experimentally. Finally, we discuss possible
implications of our results for quantum information processing with Li spin
qubits in Si.",1210.8164v1
2017-10-13,Possible quadrupolar nematic phase in the frustrated spin chain LiCuSbO$_4$: an NMR investigation,"The frustrated one-dimensional (1D) quantum magnet LiCuSbO$_4$ is one rare
realization of the $J_1-J_2$ spin chain model with an easily accessible
saturation field, formerly estimated to 12~T. Exotic multipolar nematic phases
were theoretically predicted in such compounds just below the saturation field,
but without unambiguous experimental observation so far. In this paper we
present extensive experimental research of the compound in the wide temperature
(30mK$-$300K) and field (0$-$13.3T) range by muon spin rotation ($\mu$SR),
$^7$Li nuclear magnetic resonance (NMR) and magnetic susceptibility (SQUID).
$\mu$SR experiments in zero magnetic field demonstrate the absence of long
range 3D ordering down to 30mK. Together with former heat capacity data [S.E.
Dutton \emph{et al}, Phys. Rev. Lett. 108, 187206 (2012)], magnetic
susceptibility measurements suggest short range correlated vector chiral phase
in the field range $0-4$T. In the intermediate field values (5$-$12T), the
system enters in a 3D ordered spin density wave phase with 0.75$\mu_B$ per
copper site at lowest temperatures (125mK), estimated by NMR. At still higher
field, the magnetization is found to be saturated above 13T where the spin
lattice $T_1^{-1}$ relaxation reveals a spin gap estimated to 3.2(2)K. We
narrow down the possibility of observing a multipolar nematic phase to the
range 12.5$-$13T.",1710.05004v1
2021-11-05,Quadrupolar magnetic excitations in an isotropic spin-1 antiferromagnet,"The microscopic origins of emergent behaviours in condensed matter systems
are encoded in their excitations. In ordinary magnetic materials, single
spin-flips give rise to collective dipolar magnetic excitations called magnons.
Likewise, multiple spin-flips can give rise to multipolar magnetic excitations
in magnetic materials with spin $\mathbf{S} \boldsymbol{\ge} \mathbf{1}$.
Unfortunately, since most experimental probes are governed by dipolar selection
rules, collective multipolar excitations have generally remained elusive. For
instance, only dipolar magnetic excitations have been observed in isotropic
$\mathbf{S}\boldsymbol{=}\mathbf{1}$ Haldane spin systems. Here, we unveil a
hidden quadrupolar constituent of the spin dynamics in antiferromagnetic
$\mathbf{S}\boldsymbol{=}\mathbf{1}$ Haldane chain material
Y$_\mathbf{2}$BaNiO$_\mathbf{5}$ using Ni $\mathbf{L_3}$-edge resonant
inelastic x-ray scattering. Our results demonstrate that pure quadrupolar
magnetic excitations can be probed without direct interactions with dipolar
excitations or anisotropic perturbations. Originating from on-site double
spin-flip processes, the quadrupolar magnetic excitations in
Y$_\mathbf{2}$BaNiO$_\mathbf{5}$ show a remarkable dual nature of collective
dispersion. While one component propagates as non-interacting entities, the
other behaves as a bound quadrupolar magnetic wave. This result highlights the
rich and largely unexplored physics of higher-order magnetic excitations.",2111.03625v1
2022-05-09,Fragment-orbital-dependent spin fluctuations in the single-component molecular conductor [Ni(dmdt)$_2$],"Motivated by recent nuclear magnetic resonance experiments, we calculated the
spin susceptibility, Knight shift, and spin-lattice relaxation rate
($1/T_{1}T$) of the single-component molecular conductor [Ni(dmdt)$_2$] using
the random phase approximation in a multi-orbital Hubbard model describing the
Dirac nodal line electronic system in this compound. This Hubbard model is
composed of three fragment orbitals and on-site repulsive interactions obtained
using ab initio many-body perturbation theory calculations. We found
fragment-orbital-dependent spin fluctuations with the momentum
$\textbf{q}$=$\textbf{0}$ and an incommensurate value of the wavenumber
$\textbf{q}$=$\textbf{Q}$ at which a diagonal element of the spin
susceptibility is maximum. The $\textbf{q}$=$\textbf{0}$ and $\textbf{Q}$
responses become dominant at low and high temperatures, respectively, with the
Fermi-pocket energy scale as the boundary. We show that $1/T_{1}T$ decreases
with decreasing temperature but starts to increase at low temperature owing to
the $\textbf{q}$=$\textbf{0}$ spin fluctuations, while the Knight shift keeps
monotonically decreasing. These properties are due to the intra-molecular
antiferromagnetic fluctuations caused by the characteristic wave functions of
this Dirac nodal line system, which is described by an $n$-band ($n\geq 3$)
model. We show that the fragment orbitals play important roles in the magnetic
properties of [Ni(dmdt)$_2$].",2205.04020v4
2022-05-24,Emission of coherent THz magnons in an antiferromagnetic insulator triggered by ultrafast spin-phonon interactions,"Antiferromagnetic materials have been proposed as new types of narrowband THz
spintronic devices owing to their ultrafast spin dynamics. Manipulating
coherently their spin dynamics, however, remains a key challenge that is
envisioned to be accomplished by spin-orbit torques or direct optical
excitations. Here, we demonstrate the combined generation of broadband THz
(incoherent) magnons and narrowband (coherent) magnons at 1 THz in low damping
thin films of NiO/Pt. We evidence, experimentally and through modelling, two
excitation processes of magnetization dynamics in NiO, an off-resonant
instantaneous optical spin torque and a strain-wave-induced THz torque induced
by ultrafast Pt excitation. Both phenomena lead to the emission of a THz signal
through the inverse spin Hall effect in the adjacent heavy metal layer. We
unravel the characteristic timescales of the two excitation processes found to
be < 50 fs and > 300 fs, respectively, and thus open new routes towards the
development of fast opto-spintronic devices based on antiferromagnetic
materials.",2205.11965v1
2022-06-06,Probing spin dynamics of ultra-thin van der Waals magnets via photon-magnon coupling,"Layered van der Waals (vdW) magnets can maintain a magnetic order even down
to the single-layer regime and hold promise for integrated spintronic devices.
While the magnetic ground state of vdW magnets was extensively studied, key
parameters of spin dynamics, like the Gilbert damping, crucial for designing
ultra-fast spintronic devices, remains largely unexplored. Despite recent
studies by optical excitation and detection, achieving spin wave control with
microwaves is highly desirable, as modern integrated information technologies
predominantly are operated with these. The intrinsically small numbers of
spins, however, poses a major challenge to this.
  Here, we present a hybrid approach to detect spin dynamics mediated by
photon-magnon coupling between high-Q superconducting resonators and ultra-thin
flakes of Cr$_2$Ge$_2$Te$_6$ (CGT) as thin as 11\,nm. We test and benchmark our
technique with 23 individual CGT flakes and extract an upper limit for the
Gilbert damping parameter. These results are crucial in designing on-chip
integrated circuits using vdW magnets and offer prospects for probing spin
dynamics of monolayer vdW magnets.",2206.02460v2
2023-01-10,Magnetic anisotropy and low-energy spin dynamics in the van der Waals compounds Mn$_{2}$P$_{2}$S$_{6}$ and MnNiP$_{2}$S$_{6}$,"We report the detailed high-field and high-frequency electron spin resonance
(HF-ESR) spectroscopic study of the single-crystalline van der Waals compounds
Mn$_{2}$P$_{2}$S$_{6}$ and MnNiP$_{2}$S$_{6}$. Analysis of magnetic excitations
shows that in comparison to Mn$_{2}$P$_{2}$S$_{6}$ increasing the Ni content
yields a larger magnon gap in the ordered state and a larger g-factor value and
its anisotropy in the paramagnetic state. The studied compounds are found to be
strongly anisotropic having each the unique ground state and type of magnetic
order. Stronger deviation of the g-factor from the free electron value in the
samples containing Ni suggests that the anisotropy of the exchange is an
important contributor to the stabilization of a certain type of magnetic order
with particular anisotropy. At temperatures above the magnetic order, we have
analyzed the spin-spin correlations resulting in a development of slowly
fluctuating short-range order. They are much stronger pronounced in
MnNiP$_{2}$S$_{6}$ compared to Mn$_{2}$P$_{2}$S$_{6}$. The enhanced spin
fluctuations in MnNiP$_{2}$S$_{6}$ are attributed to the competition of
different types of magnetic order. Finally, the analysis of the temperature
dependent critical behavior of the magnon gaps below the ordering temperature
in Mn$_{2}$P$_{2}$S$_{6}$ suggests that the character of the spin wave
excitations in this compound undergoes a field induced crossover from a 3D-like
towards 2D XY regime.",2301.04239v2
2011-11-17,Resonant Alfven waves in partially ionized plasmas of the solar atmosphere,"Context. Magnetohydrodynamic (MHD) waves are ubiquitous in the solar
atmosphere. In magnetic waveguides resonant absorption due to plasma
inhomogeneity naturally transfers wave energy from large-scale motions to
small-scale motions. In the cooler parts of the solar atmosphere as, e.g., the
chromosphere, effects due to partial ionization may be relevant for wave
dynamics and heating. Aims. We study resonant Alfven waves in partially ionized
plasmas. Methods. We use the multifluid equations in the cold plasma
approximation. We investigate propagating resonant MHD waves in partially
ionized flux tubes. We use approximate analytical theory based on normal modes
in the thin tube and thin boundary approximations along with numerical
eigenvalue computations. Results. We find that the jumps of the wave
perturbations across the resonant layer are the same as in fully ionized
plasmas. The damping length due to resonant absorption is inversely
proportional to the frequency, while that due to ion-neutral collisions is
inversely proportional to the square of the frequency. For observed frequencies
in the solar atmosphere, the amplitude of MHD kink waves is more efficiently
damped by resonant absorption than by ion-neutral collisions. Conclusions. Most
of the energy carried by chromospheric kink waves is converted into localized
azimuthal Alfven waves that can deposit energy in the coronal medium. The
dissipation of wave energy in the chromosphere due to ion-neutral collisions is
only effective for high-frequency waves. The chromosphere acts as a filter for
kink waves with periods shorter than 10 s.",1111.4134v1
2014-03-17,Spin resonance without spin splitting,"We predict that a single-level quantum dot without discernible splitting of
its spin states develops a spin-precession resonance in charge transport when
embedded into a spin valve. The resonance occurs in the generic situation of
Coulomb blockaded transport with ferromagnetic leads whose polarizations
deviate from perfect antiparallel alignment. The resonance appears when
electrically tuning the interaction-induced exchange field perpendicular to one
of the polarizations -- a simple condition relying on vectors in contrast to
usual resonance conditions associated with energy splittings. The spin
resonance can be detected by stationary dI/dV spectroscopy and by oscillations
in the time-averaged current using a gate-pulsing scheme. The generic
noncollinearity of the ferromagnets and junction asymmetry allow for an
all-electric determination of the spin-injection asymmetry, the anisotropy of
spin relaxation, and the magnitude of the exchange field. We also investigate
the impact of a nearby superconductor on the resonance position. Our simplistic
model turns out to be generic for a broad class of coherent few-level quantum
systems.",1403.4002v2
2022-10-21,Optical spin-wave detection beyond the diffraction limit,"Spin waves are proposed as information carriers for next-generation computing
devices because of their low power consumption. Moreover, their wave-like
nature allows for novel computing paradigms. Conventional methods to detect
spin waves are based either on electrical induction, limiting the downscaling
and efficiency complicating eventual implementation, or on light scattering,
where the minimum detectable spin-wave wavelength is set by the wavelength of
the laser. In this Article we demonstrate magneto-optical detection of spin
waves beyond the diffraction limit using a metallic grating that selectively
absorbs laser light. Specifically, we demonstrate the detection of propagating
spin waves with a wavelength of 700 nm using a diffraction-limited laser spot
with a size of 10 $\mu$m in 20 nm thick Py strips. Additionally, we show that
this grating is selective to the wavelength of the spin wave, providing
wavevector-selective spin-wave detection. This should open up new avenues
towards the integration of the burgeoning fields of photonics and magnonics,
and aid in the optical detection of spin waves in the short-wavelength exchange
regime for fundamental research.",2210.12016v1
2004-07-26,Powerful gravitational-wave bursts from supernova neutrino oscillations,"During supernova core collapse and bounce resonant active-to-active, as well
as active-to-sterile, neutrino ($\nu$) oscillations can take place. Over this
phase weak magnetism increases antineutrino mean free paths, and thus its
luminosity. Because oscillations feed mass-energy into the target $\nu$
species, the large mass-squared difference between $\nu$ states implies a huge
amount of power to be given off as gravitational waves (GWs) due to the
universal {\it spin-rotation} and the spin-magnetic coupling driven $\nu$
anisotropic flow, which is coherent over the oscillation length. The spacetime
strain produced is about two orders of magnitude larger than those from $\nu$
difussion or neutron star matter anisotropies. GWs observatories as LIGO,
VIRGO, GEO-600, TAMA-300, etc., can search for these bursts far out to the
VIRGO cluster of galaxies.",0407526v1
1999-06-05,Submillimeter Wave ESR Study of Spin Gap Excitations in CuGeO3,"Transitions between the ground singlet state to the excited triplet state has
been observed in CuGeO3 by means of submillimeter wave electron spin resonance.
The strong absorption intensity shows the break down of the selection rule. The
energy gap at zero field is evaluated to be 570 GHz(2.36 meV) and this value is
nearly identical to the gap at the zone center observed by inelastic neutron
scattering. The absorption intensity shows strong field orientation dependence
but shows no significant dependence on magnetic field intensity. These features
have been explained by considering the existence of Dzyaloshinsky-Moriya (DM)
antisymmetric exchange interaction. The doping effect on this singlet-triplet
excitation has been also studied. A drastic broadening of the absorption line
is observed by the doping of only 0.5 % of Si.",9906074v1
2000-09-20,Quantum Fluctuations in the Frustrated Antiferromagnet Sr_2Cu_3O_4Cl_2,"Sr_2Cu_3O_4Cl_2 is an antiferromagnet consisting of weakly coupled CuO planes
which comprise two weakly interacting antiferromagnetic subsystems, I and II,
which order at respective temperatures T_I \approx 390K and T_{II} \approx 40K.
Except asymptotically near the ordering temperature, these systems are good
representations of the two-dimensional quantum spin 1/2 Heisenberg model. For
T< T_{II} there are four low-energy modes at zero wave vector, three of whose
energies are dominated by quantum fluctuations. For T_{II} < T < T_I there are
two low energy modes. The mode with lower energy is dominated by quantum
fluctuations. Our calculations of the energies of these modes (including
dispersion for wave vectors perpendicular to the CuO planes) agree extremely
well with the experimental results of inelastic neutron scattering (in the
accompanying paper) and for modes in the sub meV range observed by electron
spin resonance. The parameters needed to describe quantum fluctuations are
either calculated here or are taken from the literature. These results show
that we have a reasonable qualitative understanding of the band structure of
the lamellar cuprates needed to calculate the anisotropic exchange constants
used here.",0009315v1
2004-01-21,Theory of spinor Fermi and Bose gases in tight atom waveguides,"Divergence-free pseudopotentials for spatially even and odd-wave interactions
in spinor Fermi gases in tight atom waveguides are derived. The Fermi-Bose
mapping method is used to relate the effectively one-dimensional fermionic
many-body problem to that of a spinor Bose gas. Depending on the relative
magnitudes of the even and odd-wave interactions, the N-atom ground state may
have total spin S=0, S=N/2, and possibly also intermediate values, the case
S=N/2 applying near a p-wave Feshbach resonance, where the N-fermion ground
state is space-antisymmetric and spin-symmetric. In this case the fermionic
ground state maps to the spinless bosonic Lieb-Liniger gas. An external
magnetic field with a longitudinal gradient causes a Stern-Gerlach spatial
separation of the corresponding trapped Fermi gas with respect to various
values of $S_z$.",0401402v2
2005-07-20,Novel Phase Transition Near the Quantum Critical Point in the Filled-Skutterudite Compound CeOs4Sb12: an Sb-NQR Study,"We report on a novel phase transition at $T$ = 0.9 K in the Ce-based
filled-skutterudite compound CeOs$_{4}$Sb$_{12}$ via measurements of the
nuclear-spin lattice relaxation rate $1/T_{1}$ and nuclear quadrupole resonance
(NQR) spectrum of Sb nuclei. The temperature ($T$) dependence of $1/T_1$
behaves as if approaching closely an antiferromagnetic (AFM) quantum critical
point (QCP), following the relation $1/T_{1}\propto T/(T-T_{\rm N})^{1/2}$ with
$T_{\rm N} = 0.06$ K in the range of $T=1.3-25$ K. The onset of either the
spin-density-wave (SDW) or charge-density-wave (CDW) order at $T_{\rm 0} = 0.9$
K, that is, of the first order, is evidenced by a broadening of the NQR
spectrum and a marked reduction in $1/T_1$ just below $T_{\rm 0}$. The
$f$-electron-derived correlated band realized in CeOs$_{4}$Sb$_{12}$ is
demonstrated to give rise to the novel phase transition on the verge of AFM
QCP.",0507470v1
2006-04-04,Experimental evidence of paired hole states in model high-$T_c$ compounds,"The distribution of holes in Sr$_{14-x}$Ca$_x$Cu$_{24}$O$_{41}$ (SCCO) is
revisited with semi-emperical reanalysis of the x-ray absorption (XAS) data and
exact-diagonalized cluster calculations. A new interpretation of the XAS data
leads to much larger ladder hole densities than previously suggested. These new
hole densities lead to a simple interpretation of the hole crystal (HC)
recently reported with 1/3 and 1/5 wave vectors along the ladder. Our
interpretation is consistent with paired holes in the rung of the ladders.
Exact diagonalization results for a minimal model of the doped ladders suggest
that the stabilization of spin structures consisting of 4 spins in a square
plaquette as a result of resonance valence bond (RVB) physics suppresses the
hole crystal with a 1/4 wave vector.",0604101v1
1999-10-25,Neutrino Oscillations in Electromagnetic Fields,"Oscillations of neutrinos $\nu_L \leftrightarrow \nu_R$ in presence of an
arbitrary electromagnetic field are considered. We introduce the Hamiltonian
for the neutrino spin evolution equation that accounts for possible effects of
interaction of neutrino magnetic $\mu$ and electric $\epsilon$ dipole moments
with the transversal (in respect to the neutrino momentum) and also the
longitudinal components of electromagnetic field. Using this Hamiltonian we
predict the new types of resonances in the neutrino oscillations $\nu_L
\leftrightarrow \nu_R$ in the presence of the field of an electromagnetic wave
and in combination of an electromagnetic wave and constant magnetic field. The
possible influence of the longitudinal magnetic field on neutrino oscillations
is emphasized.",9910476v4
2008-02-28,Chromium at High Pressures: Weak Coupling and Strong Fluctuations in an Itinerant Antiferromagnet,"The spin- and charge-density-wave order parameters of the itinerant
antiferromagnet chromium are measured directly with non-resonant x-ray
diffraction as the system is driven towards its quantum critical point with
high pressure using a diamond anvil cell. The exponential decrease of the spin
and charge diffraction intensities with pressure confirms the harmonic scaling
of spin and charge, while the evolution of the incommensurate ordering vector
provides important insight into the difference between pressure and chemical
doping as means of driving quantum phase transitions. Measurement of the charge
density wave over more than two orders of magnitude of diffraction intensity
provides the clearest demonstration to date of a weakly-coupled, BCS-like
ground state. Evidence for the coexistence of this weakly-coupled ground state
with high-energy excitations and pseudogap formation above the ordering
temperature in chromium, the charge-ordered perovskite manganites, and the blue
bronzes, among other such systems, raises fundamental questions about the
distinctions between weak and strong coupling.",0802.4273v1
2009-02-02,Magnetic domain-wall motion by propagating spin waves,"We found by micromagnetic simulations that the motion of a transverse wall
(TW) type domain wall in magnetic thin-film nanostripes can be manipulated via
interaction with spin waves (SWs) propagating through the TW. The velocity of
the TW motion can be controlled by changes of the frequency and amplitude of
the propagating SWs. Moreover, the TW motion is efficiently driven by specific
SW frequencies that coincide with the resonant frequencies of the local modes
existing inside the TW structure. The use of propagating SWs, whose frequencies
are tuned to those of the intrinsic TW modes, is an alternative approach for
controlling TW motion in nanostripes.",0902.0220v1
2011-07-04,Influence of randomness and retardation on the FMR-linewidth,"The theory predicts that the spin-wave lifetime $\tau_L$ and the linewidth of
ferromagnetic resonance $\Delta B$ can be governed by random fields and spatial
memory. To that aim the effective field around which the magnetic moments
perform a precession is superimposed by a stochastic time dependent magnetic
field with finite correlation time. The magnetization dynamics is altered by
inclusion of a spatial memory effect monitoring a non-local interaction of size
$\xi$. The underlying Landau-Lifshitz-Gilbert equation (LLG) is modified
accordingly. The stochastic LLG is equivalent to a Fokker-Planck equation which
enables to calculate the mean values of the magnetization vector. Within the
spin-wave approximation we present an analytical solution for the excitation
energy and its damping. The lifetime and the linewidth are analyzed depending
on the strength of the random field $D$ and its correlation time $\tau_c$ as
well as the retardation strength $\Gamma_0$ and the size $\xi$. Whereas
$\tau_L$ decreases with increasing $D$, retardation strength $\Gamma_0$ and
$\tau_c$, the lifetime is enhanced for growing width $\xi$ of the spatial
retardation kernel. In the same manner we calculate the experimentally
measurable linewidth $\Delta B$ is increased strongly when the correlation time
$\tau_c$ ranges in the nanosecond interval.",1107.0638v1
2015-05-29,Time-resolved imaging of pulse-induced magnetization reversal with a microwave assist field,"The reversal of the magnetization under the influence of a field pulse has
been previously predicted to be an incoherent process with several competing
phenomena such as domain wall relaxation, spin wave-mediated instability
regions, and vortex-core mediated reversal dynamics. However, there has been no
study on the direct observation of the switching process with the aid of a
microwave signal input. We report a time-resolved imaging study of
magnetization reversal in patterned magnetic structures under the influence of
a field pulse with microwave assistance. The microwave frequency is varied to
demonstrate the effect of resonant microwave-assisted switching. We observe
that the switching process is dominated by spin wave dynamics generated as a
result of magnetic instabilities in the structures, and identify the
frequencies that are most dominant in magnetization reversal.",1505.07936v1
2015-10-12,Spin wave approach to the two-magnon Raman scattering in an J1x-J1y-J2-Jc antiferromagnetic Heisenberg model,"We study the two-magnon non-resonant Raman scattering in the (pi,pi) and
(pi,0) ordered antiferromagnetic phases of a J1x-J1y-J2-Jc Heisenberg model on
the tetragonal lattice within the framework of the spin-wave theory. We discuss
the effects of various tuning factors to the two-magnon Raman spectra. We find
that both the magnetic frustration J2/J1 and the interlayer exchange coupling
Jc may significantly affect the spectra in both the B1g and A1g' channels in
the (pi,pi) Neel ordered phase. Moreover, we find a splitting of the two-magnon
peak in the (pi,0) antiferromagnetic phase. We further discuss the implications
of our results to the BaMnBi2 and iron pnictide systems.",1510.03359v1
2016-04-20,High-Capacity Angularly-Multiplexed Holographic Memory Operating at the Single Photon Level,"We experimentally demonstrate an angularly-multiplexed holographic memory
capable of intrinsic generation, storage and retrieval of multiple photons,
based on off-resonant Raman interaction in warm rubidium-87 vapors. The memory
capacity of up to 60 independent atomic spin-wave modes is evidenced by
analyzing angular distributions of coincidences between Stokes and time-delayed
anti-Stokes light, observed down to the level of single spin-wave excitation
during several-$\mu$s memory lifetime. We also propose how to practically
enhance rates of single and multiple photons generation by combining our
multimode emissive memory with existing fast optical switches.",1604.06049v4
2016-07-27,Dressed-state electromagnetically induced transparency for light storage in uniform phase spin-waves,"We present, experimentally and theoretically, a scheme for dressed-state
electromagnetically induced transparency (EIT) in a three-step cascade system
where a four-level system is mapped into an effective three-level system.
Theoretical analysis reveals that the scheme provides coherent state control
via adiabatic following and provides a generalized protocol for light storage
in uniform phase spin-waves that are insensitive to motional dephasing. The
three-step driving enables a number of other features including spatial
selectivity of the excitation region within the atomic medium, and kick-free
and Doppler-free excitation that produces narrow resonances in thermal vapor.
As a proof of concept we present an experimental demonstration of the
generalized EIT scheme using the $6S_{1/2} \rightarrow 6P_{3/2} \rightarrow
7S_{1/2} \rightarrow 8P_{1/2}$ excitation path in thermal cesium vapor. This
technique could be applied to cold and thermal ensembles to enable longer
storage times for Rydberg polaritons.",1607.08031v1
2018-05-31,Disorder correction to the Néel temperature of ruthenium-doped BaFe$_2$As$_2$: Theoretical analysis,"We analyze theoretically nuclear magnetic resonance data for the spin-density
wave phase in the ruthenium-doped BaFe$_2$As$_2$. Since inhomogeneous
distribution of Ru~atoms introduces disorder into the system, experimentally
observable random spatial variations of the spin-density wave order parameter
emerge. Using perturbation theory for the Landau functional, we estimate the
disorder-induced correction to the N\'{e}el temperature for this material.
Calculated correction is significantly smaller than the N\'{e}el temperature
itself for all experimentally relevant doping levels. This implies that the
N\'{e}el temperature is quite insensitive to the disorder created by the
dopants.",1805.12568v2
2018-06-26,Efficient continuous wave noise spectroscopy beyond weak coupling,"The optimization of quantum control for physical qubits relies on accurate
noise characterization. Probing the spectral density $S(\omega)$ of
semi-classical phase noise using a spin interacting with a continuous-wave (CW)
resonant excitation field has recently gained attention. CW noise spectroscopy
protocols have been based on the generalized Bloch equations (GBE) or the
filter function formalism, assuming weak coupling to a Markovian bath. However,
this standard protocol can substantially underestimate $S(\omega)$ at low
frequencies when the CW pulse amplitude becomes comparable to $S(\omega)$.
Here, we derive the coherence decay function more generally by extending it to
higher orders in the noise strength and discarding the Markov approximation.
Numerical simulations show that this provides a more accurate description of
the spin dynamics compared to a simple exponential decay, especially on short
timescales. Exploiting these results, we devise a protocol that uses an
experiment at a single CW pulse amplitude to extend the spectral range over
which $S(\omega)$ can be reliably determined to $\omega=0$.",1806.10043v1
2019-11-19,Doing spin physics with unpolarized particles,"Twisted, or vortex, particles refer to freely propagating non-plane-wave
states with helicoidal wave fronts. In this state, the particle possesses a
non-zero orbital angular momentum with respect to its average propagation
direction. Twisted photons and electrons have been experimentally demonstrated,
and creation of other particles in twisted states can be anticipated. If
brought in collisions, twisted states offer a new degree of freedom to particle
physics, and it is timely to analyze what new insights may follow. Here, we
theoretically investigate resonance production in twisted photon collisions and
twisted $e^+e^-$ annihilation and show that these processes emerge as a
completely novel probe of spin and parity-sensitive observables in fully
inclusive cross sections with unpolarized initial particles. This is possible
because the initial state with a non-zero angular momentum explicitly breaks
the left-right symmetry even when averaging over helicities. In particular, we
show how one can produce almost $100\%$ polarized vector mesons in unpolarized
twisted $e^+e^-$ annihilation and how to control its polarization state.",1911.08423v1
2017-06-10,Mapping the magnonic landscape in patterned magnetic structures,"We report the development of a hybrid numerical / analytical model capable of
mapping the spatially-varying distributions of the local ferromagnetic
resonance (FMR) frequency and dynamic magnetic susceptibility in a wide class
of patterned and compositionally modulated magnetic structures. Starting from
the numerically simulated static micromagnetic state, the magnetization is
deliberately deflected orthogonally to its equilibrium orientation, and the
magnetic fields generated in response to this deflection are evaluated using
micromagnetic software. This allows us to calculate the elements of the
effective demagnetizing tensor, which are then used within a linear analytical
formalism to map the local FMR frequency and dynamic magnetic susceptibility.
To illustrate the typical results that one can obtain using this model, we
analyze three micromagnetic systems boasting non-uniformity in either one or
two dimensions, and successfully explain the spin-wave emission observed in
each case, demonstrating the ubiquitous nature of the Schl\""omann excitation
mechanism underpinning the observations. Finally, the developed model of local
FMR frequency could be used to explain how spin waves could be confined and
steered using magnetic non-uniformities of various origins, rendering it a
powerful tool for the mapping of the graded magnonic index in magnonics.",1706.03212v1
2020-11-05,Matrix Product Wave Function of the Ground State and Elementary Excitation in the Spin-1/2 Chain,"We present a variational matrix product state (vMPS) for the ground state of
the spin-1/2 Heisenberg model. The MPS effectively organizes the various dimer
configurations, in faithful reflection of the resonating valence bond (RVB)
picture of the spin liquid, with the energy only 0.024% higher than the exact
value given by Bethe ansatz. Building on the ground-state vMPS, the one-spin
wave function is constructed in a simple manner with the dispersion that
matches well with the exact spectrum. The vMPS scheme is applied to the family
of Hamiltonian extrapolating between the Heisenberg model and the
Majumdar-Ghosh model.",2011.02625v1
2017-04-20,Charge-density-wave order takes over antiferromagnetism in Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6}$ superconductors,"Superconductivity appears in the cuprates when a spin order is destroyed,
while the role of charge is less known. Recently, charge density wave (CDW) was
found below the superconducting dome in YBa$_2$Cu$_3$O$_y$ when a high magnetic
field is applied perpendicular to the CuO$_2$ plane, which was suggested to
arise from incipient CDW in the vortex cores that becomes overlapped. Here, by
$^{63}$Cu-nuclear magnetic resonance, we report the discovery of CDW induced by
an in-plane field that does not create vortex cores in the plane, setting in
above the dome in single-layered Bi$_2$Sr$_{2-x}$La$_x$CuO$_6$.The onset
temperature $T_{\rm CDW}$ takes over the antiferromagnetic order temperature
$T_{\rm N}$ beyond a critical doping level at which superconductivity starts to
emerge, and scales with the psudogap temperature $T^{*}$. These results provide
important insights into the relationship between spin order, CDW and the
pseudogap, and their connections to high-temperature superconductivity.",1704.06169v2
2018-12-12,Substrate induced magnetic anisotropies and magneto-optical response in YIG nanosized epitaxial films on NdGG(111),"Nanosized Y3Fe5O12 epitaxial films have been grown on Nd3Ga5O12 substrates
using laser molecular beam epitaxy method. Magneto-optical polar Kerr effect,
ferromagnetic resonance and spin wave propagation measurements show that the
stress-related anisotropy field has an opposite sign, compared to that in the
YIG/GGG systems. This leads to a considerable decrease of the effective
magnetization that opens a perspective to get YIG films with perpendicular
magnetization for utilizing forward volume spin waves. Longitudinal
magnetooptical Kerr effect magnetometry reveals a large contribution of
quadratic in magnetization terms into dielectric permittivity tensor at optical
frequencies. This effect strongly increases with temperature decrease and is
explained by magnetization of the interface Nd3+ ions that are exchange coupled
to the Fe3+ ions.",1901.10800v1
2019-09-26,Coherent charge and magnetic ordering in Ho/Y superlattice revealed by element-selective x-ray scattering,"Magnetic rare-earth / non-magnetic metal superlattices are well-known to
display chiral spin helices in the rare-earth layers that propagate coherently
across the non-magnetic layers. However, the underlying mechanism that
preserves the magnetic phase and chirality coherence across the non-magnetic
layers has remained elusive. In this Letter, we use resonant and
element-specific x-ray scattering to evidence directly the formation of two
fundamentally different long-range modulations in a Holmium/Yttrium (Ho/Y)
multilayer: the known Ho chiral spin helix with periodicity 25 {\AA}, and a
newly observed charge density wave with periodicity 16 {\AA} that propagates
through both the Ho and non-magnetic Y layer. With x-ray circular magnetic
dichroism measurements ruling out the existence of a magnetic proximity effect
induced moment in the non-magnetic Y layers, we propose that the charge density
wave is also chiral, thus providing the means for the transmittance of magnetic
chirality coherence between Ho layers.",1909.12372v2
2020-02-05,Twisted particle collisions: a new tool for spin physics,"Collisions of twisted particles --- that is, non-plane-wave states of
photons, electrons, or any other particle, equipped with a non-zero orbital
angular momentum (OAM) with respect to its propagation direction --- offer
novel ways to probe particle structure and interactions. In the recent paper
\cite{Ivanov:2019vxe}, we argued that resonance production in twisted photon
collisions or twisted $e^+e^-$ annihilation gives access to parity- and
spin-sensitive observables in inclusive cross sections, even when the initial
particles are unpolarized. Here, we explore these features in detail, providing
a qualitative picture and illustrating it with numerical examples. We show how
one can detect parity-violating effects in collisions of unpolarized twisted
photons and how one can produce almost $100\%$ polarized vector mesons in
unpolarized twisted $e^+e^-$ annihilation. These examples highlight the
unprecedented level of control over polarization offered by twisted particles,
impossible in the usual plane wave collisions.",2002.01703v1
2022-03-09,Toward discovering the excited $Ω$ baryons through nonleptonic weak decays of $Ω_c$,"The nonleptonic weak decay processes $\Omega_c \to
\Omega\pi^+/\Omega(1P)\pi^+/\Omega(1D)\pi^+/\Omega(2S)\pi^+$ are studied using
the constituent quark model. The branching fraction of $\Omega_c \to
\Omega\pi^+$ is predicted to be $1.1\%$. Considering the newly observed
$\Omega(2012)$ resonance as a conventional $1P$-wave $\Omega$ excite state with
spin-parity $J^P=3/2^-$, the newly measured ratio $\mathcal{B}[\Omega_c\to
\Omega(2012)\pi^+ \to (\Xi\bar{K})^-\pi^+ ]/\mathcal{B}[\Omega_c\to \Omega
\pi^+]$ at Belle can be well understood. Besides, the production rates for the
missing $1P-$wave state $\Omega (1^2P_{1/2^-})$, two spin quartet $1D-$wave
states $\Omega (1^4D_{1/2^+})$ and $\Omega (1^4D_{3/2^+})$, and two $2S$-wave
states $\Omega(2^2S_{1/2^+})$ and $\Omega(2^4S_{3/2^+})$ are also investigated.
It is expected that these missing excited $\Omega$ baryons should have large
potentials to be discovered through the nonleptonic weak decays of $\Omega_c$
in forthcoming experiments by Belle II and/or LHCb.",2203.04458v2
2022-05-23,Linear Flavor-Wave Analysis of SU(4)-Symmetric Tetramer Model with Population Imbalance,"We study the quantum magnetism of the SU(4) Mott insulator in a square
optical superlattice, in which atoms with four nuclear-spin components strongly
interact with each other, in the presence of an external field that controls
the imbalance between the population of two components and that of the other
two. This is a natural extension of the physics of spin-dimer materials under
strong magnetic field. We apply an extended linear flavor-wave theory based on
four-site plaquettes and unveil the ground-state phase diagram and excitation
spectra. When the population of the four components is balanced and the
plaquesttes are weakly coupled, the ground state is approximately given by the
direct product of local SU(4)-singlet states. In high-field, the system reaches
a ""saturated state"" where only two components are present. Our main finding is
a nontrivial intermediate phase, which has a checkerboard-like arrangement of
the SU(4)-singlet and four-site resonating-valence-bond states.",2205.11155v1
2023-05-10,Investigation of Spin-Wave Dynamics in Gyroid Nanostructures,"A new concept in magnonics studies the dynamics of spin waves (SWs) in
three-dimensional nanosystems. It is a natural evolution from conventionally
used planar systems to explore magnetization configurations and dynamics in 3D
nanostructures with lengths near intrinsic magnetic scales. In this work, we
perform broadband ferromagnetic resonance (BBFMR) measurements and
micromagnetic simulations of nanoscale magnetic gyroids - a periodic chiral
structure consisting entirely of chiral triple junctions. Our results show
unique properties of the network, such as the localization of the SW modes,
evoking their topological properties, and the substantial sensitivity to the
direction of the static magnetic field. The presented results open a wide range
of applications in the emerging field of 3D magnonic crystals and spintronics.",2305.06319v2
2023-12-12,Interacting Floquet topological magnons in laser-irradiated Heisenberg honeycomb ferromagnets,"When a Heisenberg honeycomb ferromagnet is irradiated by high frequency
circularly polarized light, the underlying uncharged magnons acquire a time
dependent Aharonov Casher phase, which makes it a Floquet topological magnon
insulator. In this context, we investigate the many body interaction effects of
Floquet magnons in laser irradiated Heisenberg honeycomb ferromagnets with
ocontaining Dzyaloshinskii Moriya interaction under the application of
circularly polarized off resonant light. We demonstrate that the quantum
ferromagnet systems periodically laser driven exhibits temperature driven
topological phase transitions due to Floquet magnon magnon interactions. The
thermal Hall effect of Floquet magnons serves as a prominent signature for
detecting these many body effects near the critical point, enabling
experimental investigation into this phenomenon. Our study complements the lack
of previous theoretical works that the topological phase transition of the
Floquet magnon under the linear spin wave approximation is only tunable by the
light field. Our study presents a novel approach for constructing Floquet
topological phases in periodically driven quantum magnet systems that goes
beyond the limitations of the linear spin wave theory. We provide numerical
results based on the well known van der Waals quantum magnet CrX3 (X=F, Cl, Br,
and I), calling for experimental implementation.",2312.06929v1
2024-02-09,Long-lived collective Rydberg excitations in atomic gas achieved via ac-Stark lattice modulation,"Collective Rydberg excitations provide promising applications ranging from
quantum information processing, and quantum computing to ultra-sensitive
electrometry. However, their short lifetime is an immense obstacle in real-life
scenarios. The state-of-the-art methods of prolonging the lifetime were mainly
implemented for ground-state quantum memories and would require a redesign to
effectively work on different atomic transitions. We propose a protocol for
extending the Rydberg excitation lifetime, which in principle can freeze the
spin-wave and completely cancel the effects of thermal dephasing. The protocol
employs off-resonant ac-Stark lattice modulation of spin waves by interfering
two laser beams on the atomic medium. Our implementation showed that the
excitation lifetime can be extended by an order of magnitude, paving the way
towards more complex protocols for collective Rydberg excitations.",2402.06513v2
2022-02-23,Resonators with tailored optical path by cascaded-mode conversions,"Optical resonators enable the generation, manipulation, and storage of
electromagnetic waves. They are widely used in technology and fundamental
research, in telecommunications, lasers and nonlinear optics, ultra-sensitive
measurements in cavity optomechanics, and the study of light-matter
interactions in the context of cavity QED. The physics underlying their
operation is determined by the constructive interference of electromagnetic
waves at specific frequencies, giving rise to the resonance spectrum. This
mechanism causes the limitations and trade-offs of resonator design, such as
the difficulty of confining waves larger than the resonator and the fixed
relationship between free spectral range, modal linewidth, and the resonator's
refractive index and size. Here, we introduce a new class of optical
resonators, generating resonances by designing the optical path through
transverse mode coupling in a cascaded process created by mode-converting
mirrors. The generalized round-trip phase condition leads to resonator
characteristics that are markedly different from Fabry-Perot resonators and can
be tailored over a wide range, such as the largest resonant wavelength, the
free spectral range, the linewidth, and the quality factor. We confirm the
existence of these modes experimentally in an integrated waveguide cavity with
mode converters coupling two transverse modes into one supermode. The resonance
signature of the cascaded-mode resonator is a spectrum resulting from the
coherent superposition of the coupled transverse modes. We also demonstrate a
transverse mode-independent transmission through the resonator and show that
its engineered spectral properties agree with theoretical predictions.
Cascaded-mode resonators introduce properties not found in traditional
resonators and provide a mechanism to overcome the existing trade-offs in the
design of resonators in various application areas.",2202.11775v1
2019-10-24,Spin waves in ferromagnetic thin films,"A spin wave is the disturbance of intrinsic spin order in magnetic materials.
In this paper, a spin wave in the Landau-Lifshitz-Gilbert equation is obtained
based on the assumption that the spin wave maintains its shape while it
propagates at a constant velocity. Our main findings include: (1) in the
absence of Gilbert damping, the spin wave propagates at a constant velocity
with the increment proportional to the strength of the magnetic field; (2) in
the absence of magnetic field, at a given time the spin wave converges
exponentially fast to its initial profile as the damping parameter goes to zero
and in the long time the relaxation dynamics of the spin wave converges
exponentially fast to the easy-axis direction with the exponent proportional to
the damping parameter; (3) in the presence of both Gilbert damping and magnetic
field, the spin wave converges to the easy-axis direction exponentially fast at
a small timescale while propagates at a constant velocity beyond that. These
provides a comprehensive understanding of spin waves in ferromagnetic
materials.",1910.11200v1
2018-10-11,"Propagating spin waves in nanometer-thick yttrium iron garnet films: Dependence on wave vector, magnetic field strength and angle","We present a comprehensive investigation of propagating spin waves in
nanometer-thick yttrium iron garnet (YIG) films. We use broadband spin-wave
spectroscopy with integrated coplanar waveguides (CPWs) and microstrip antennas
on top of continuous and patterned YIG films to characterize spin waves with
wave vectors up to 10 rad/$\mu$m. All films are grown by pulsed laser
deposition. From spin-wave transmission spectra, parameters such as the Gilbert
damping constant, spin-wave dispersion relation, group velocity, relaxation
time, and decay length are derived and their dependence on magnetic bias field
strength and angle is systematically gauged. For a 40-nm-thick YIG film, we
obtain a damping constant of $3.5 \times 10^{-4}$ and a maximum decay length of
1.2 mm. Our experiments reveal a strong variation of spin-wave parameters with
magnetic bias field and wave vector. Spin-wave properties change considerably
up to a magnetic bias field of about 30 mT and above a field angle of
$\theta_{H} = 20^{\circ}$, where $\theta_{H} = 0^{\circ}$ corresponds to the
Damon-Eshbach configuration.",1810.04973v1
2000-07-06,Detecting Gapless Excitations above Ferromagnetic Domain Walls,"In a two or three dimensional ferromagnetic XXZ model, a low energy
excitation mode above a magnetic domain wall is gapless, whereas all of the
usual spin wave excitations moving around the whole crystal are gapful.
Although this surprising fact was already proved in a mathematically rigorous
manner, the gapless excitations have not yet been detected experimentally. For
this issue, we show theoretically that the gapless excitations appear as the
dynamical fluctuations of the experimental observable, magnetoresistance, in a
ferromagnetic wire. We also discuss other methods (e.g., ferromagnetic
resonance and neutron scattering) to detect the gapless excitations
experimentally.",0007099v1
2002-05-03,Interlayer Magnetic Frustration in Quasi-stoichiometric Li1-xNi1+xO2,"Susceptibility, high-field magnetization and submillimeter wave electron spin
resonance measurements of layered quasi-stoichiometric Li1-xNi1+xO2 are
reported and compared to isomorphic NaNiO2. A new mechanism of magnetic
frustration induced by the excess Ni ions always present in the Li layers is
proposed. We finally comment on the possible realization of an orbital liquid
state in this controversial compound.",0205059v1
2004-06-24,Magnetic fluctuations from stripes in cuprates,"Within the time-dependent Gutzwiller approximation for the Hubbard model we
compute the magnetic fluctuations of vertical metallic stripes with parameters
appropriate for La$_{1.875}$Ba$_{0.125}$CuO$_4$ (LBCO). For bond- and
site-centered stripes the excitation spectra are similar, consisting of a
low-energy incommensurate acoustic branch which merges into a ``resonance
peak'' at the antiferromagnetic wave vector and several high-energy optical
branches. The acoustic branch is similar to the result of theories assuming
localized spins whereas the optical branches are significantly different.
Results are in good agreement with a recent inelastic neutron study of LBCO.",0406589v2
2005-07-17,UV-Photoinduced Defects In Ge-Doped Optical Fibers,"We investigated the effect of continuous-wave (cw) UV laser radiation on
single-mode Ge-doped H2- loaded optical fibers. An innovative technique was
developed to measure the optical absorption (OA) induced in the samples by
irradiation, and to study its dependence from laser fluence. The combined use
of the electron spin resonance (ESR) technique allowed the structural
identification of several radiation-induced point defects, among which the
Ge(1) (GeO4 -) is found to be responsible of induced OA in the investigated
spectral region.",0507405v1
2005-11-21,Micromagnetic simulations of absoption spectra,"Further development of a previously introduced method for numerically
simulating magnetic spin waves is presented. Together with significant
improvements in speed, the method now allows one to calculate the energy
absorbed by the various modes excited by a position- and time-dependent H1
field in a ferromagnetic body of arbitrary shape in the presence of a (uniform
or non uniform) static H0 field as well as the internal exchange and anisotropy
fields. The method is applied to the case of the single vortex state in a thin
disc, a ring, and various square slabs, for which the absorption spectra are
calculated and the most strongly excited resonance modes are identified.",0511499v1
2006-05-15,Orbital Order Instability and Orbital Excitations in Degenerate Itinerant Electron Systems,"We present the theory of orbital ordering in orbital-degenerate itinerant
electron systems. After proposing the criterion of instability for orbital
ordering or orbital density wave ordering, we find that the orbital and the
spin-orbital collective excitation spectra in ferro-orbital ordered phase
exhibit finite gaps. The anomalous electronic energy spectra manifested in the
angle-resolved photoemission spectroscopy (ARPES) and the orbital occupation in
the resonant X-ray scattering (RXS) intensities are also presented for the
orbital-ordered phase.",0605379v1
2006-12-21,Spin wave excitations: The main source of the temperature dependence of Interlayer exchange coupling in nanostructures,"Quantum mechanical calculations based on an extended Heisenberg model are
compared with ferromagnetic resonance (FMR) experiments on prototype trilayer
systems Ni_7/Cu_n/Co_2/Cu(001) in order to determine and separate for the first
time quantitatively the sources of the temperature dependence of interlayer
exchange coupling. Magnon excitations are responsible for about 75% of the
reduction of the coupling strength from zero to room temperature. The remaining
25% are due to temperature effects in the effective quantum well and the
spacer/magnet interfaces.",0612568v1
1999-04-16,The spin of the $f_J(1710)$ and new effects observed in the WA102 experiment,"A partial wave analysis of the centrally produced KK and pipi systems shows
that the fJ(1710) has J = 0. In addition, a study of central meson production
as a function of the difference in transverse momentum (dPT) of the exchanged
particles shows that undisputed qqbar mesons are suppressed at small dPT
whereas the glueball candidates are enhanced and that the production cross
section for different resonances depends strongly on the azimuthal angle
between the two outgoing protons.",9904359v1
2006-05-11,Partial decay widths of baryons in the spin-momentum operator expansion method,"The cross sections for photo- and pion-induced production of baryon
resonances and their partial decay widths to the two--body and multi--body
final states are calculated in the framework of the operator expansion method.
The approach is fully relativistic invariant, and it allows us to perform
combined analyses of different reactions imposing directly the analyticity and
unitarity constraints. All formulae are given explicitly in the form used by
the Crystal Barrel collaboration in the partial wave analysis.",0605135v2
1999-03-11,Core-Polarization Contribution to the Nuclear Anapole Moment,"The importance of core contributions to the anapole moment in nuclei is
examined. A model of the core-polarization correction is presented. The model
is based on the coupling of the valence particles to the spin-dipole $J=1^{-}$
giant resonances of the core. A shell-model calculation of this correction is
presented. The single-particle moments are calculated with Woods-Saxon and
Skyrme Hartree Fock radial wave functions, and the general issues associated
with nuclear configuration mixing are discussed.",9903032v1
1995-01-19,Phonon Assisted Multimagnon Optical Absorption and Long Lived Two-Magnon States in Undoped Lamellar Copper Oxides,"We calculate the effective charge for multimagnon infrared (IR) absorption
assisted by phonons in the parent insulating compounds of cuprate
superconductors and the spectra for two-magnon absorption using interacting
spin-wave theory. Recent measured bands in the mid IR [Perkins et al. Phys.
Rev. Lett. {\bf 71} 1621 (1993)] are interpreted as involving one phonon plus a
two-magnon virtual bound state, and one phonon plus higher multimagnon
absorption processes. The virtual bound state consists of a narrow resonance
occurring when the magnon pair has total momentum close to $(\pi,0)$.",9501001v1
2008-08-07,Energy Gaps and Kohn Anomalies in Elemental Superconductors,"The momentum and temperature dependence of the lifetimes of acoustic phonons
in the elemental superconductors Pb and Nb was determined by resonant spin-echo
spectroscopy with neutrons. In both elements, the superconducting energy gap
extracted from these measurements was found to converge with sharp anomalies
originating from Fermi-surface nesting (Kohn anomalies) at low temperatures.
The results indicate electron many-body correlations beyond the standard
theoretical framework for conventional superconductivity. A possible mechanism
is the interplay between superconductivity and spin- or charge-density-wave
fluctuations, which may induce dynamical nesting of the Fermi surface.",0808.1028v1
2010-07-27,Radiative processes in external gravitational fields,"Kinematically forbidden processes may be allowed in the presence of external
gravitational fields. These ca be taken into account by introducing generalized
particle momenta. The corresponding transition probabilities can then be
calculated to all orders in the metric deviation from the field-free
expressions by simply replacing the particle momenta with their generalized
counterparts. The procedure applies to particles of any spin and to any
gravitational fields. transition probabilities, emission power, and spectra
are, to leading order, linear in the metric deviation. It is also shown how a
small dissipation term in the particle wave equations can trigger a strong
backreaction that introduces resonances in the radiative process and deeply
affects the resulting gravitational background.",1007.4834v1
2011-02-09,Local magnetic inhomogeneities observed via 75As NMR in Ba(Fe1-xNix)2As2 with H0 {\perp} c-axis,"We present field-swept 75As Nuclear Magnetic Resonance (NMR) measurements in
the spin-density wave (SDW) state of Ba(Fe1-xNix)2As2 for x=0.0072. The large
single crystals were aligned with the external field H0 perpendicular to the c
axis. The spectra are increasingly broadened as a function of doping, and are
well fit by a model of a commensurate SDW with local impurities.",1102.1936v1
2011-07-07,Antiferromagnetism of hybrid metamaterials,"We analyze a metal-dielectric structure composed of a silicon nanoparticle
coupled to a stack of split-ring resonators, and reveal the possibility of
optically-induced antiferromagnetic response of such a hybrid meta-molecule
with a staggered pattern of the induced magnetization. We show that a hybrid
metamaterial created by a periodic lattice of the meta-molecules supports
antiferromagnetic modes with a checker-board pattern and the propagation of
spin waves, opening new ways for manipulating artificial antiferromagnetism at
high frequencies with low-loss materials.",1107.1348v2
2012-04-03,Electronic structure near quantum critical point,"We studied the evolution of the electronic structure across the quantum
critical point in V doped Cr employing high resolution photoemission
spectroscopy. Experimental results exhibit signatures of pseudogap and orbital
Kondo resonance peak at low temperatures for all the compositions studied
suggesting a scenario of spin density wave quantum criticality corresponding to
orbital Kondo effect. The pseudogap and the Kondo peak gradually reduces with V
doping but remains finite at the quantum critical point indicating their
relevance in widely discussed quantum phases in correlated electron systems.
The spectral lineshape near the Fermi level exhibit (E_F - E)^{0.25} dependence
evidencing deviation from Fermi liquid behavior.",1204.0581v1
2014-02-17,Photon Polarization Precession Spectroscopy for High-Resolution Studies of Spinwaves,"A new type of spectroscopy for high-resolution studies of spin waves that
relies on resonant scattering of hard x-rays is introduced. The energy transfer
in the scattering process is encoded in the precession of the polarization
vector of the scattered photons. Thus, the energy resolution of such a
spectroscopy is independent of the bandwidth of the probing radiation. The
measured quantity resembles the intermediate scattering function of the
magnetic excitations in the sample. At pulsed x-ray sources, especially x-ray
lasers, the proposed technique allows to take single-shot spectra of the
magnetic dynamics. The method opens new avenues to study low-energy
non-equilibrium magnetic processes in a pump-probe setup.",1402.4795v1
2016-02-11,Hard exclusive pion leptoproduction,"In this talk it is reported on an analysis of hard exclusive leptoproduction
of pions within the handbag approach. It is argued that recent measurements of
this process performed by HERMES and CLAS clearly indicate the occurrence of
strong contributions from transversely polarized photons. Within the handbag
approach such gamma*_T -> pi transitions are described by the transversity GPDs
accompanied by twist-3 pion wave functions. It is shown that the handbag
approach leads to results on cross sections and single-spin asymmetries in fair
agreement with experiment. Predictions for other pseudoscalar meson channels
are also briefly discussed.8 pages",1602.03803v1
2019-11-13,Cavity-induced backscattering in a two-dimensional photonic topological system,"The discovery of robust transport via topological states in electronic,
photonic and phononic materials has deepened our understanding of wave
propagation in condensed matter with prospects for critical applications of
engineered metamaterials in communications, sensing, and controlling the
environment. Topological protection of transmission has been demonstrated in
the face of bent paths and on-site randomness in the structure. Here we measure
the propagation of microwave radiation in a topological medium possessing time
reversal symmetry with a cavity adjacent to the edge channel. A
coupled-resonance model analysis shows that the cavity is not a spin-conserving
defect and gives rise to negative time delay in transmission.",1911.06323v1
2019-04-24,Layered optomagnonic structures: Time Floquet scattering-matrix approach,"A fully dynamic theoretical approach to layered optomagnonic structures,
based on a time Floquet scattering-matrix method, is developed. Its
applicability is demonstrated on a simple design of a dual photonic-magnonic
cavity, formed by sandwiching a magnetic garnet thin film between two
dielectric Bragg mirrors, subject to continuous excitation of a perpendicular
standing spin wave. Some remarkable phenomena, including nonlinear
photon-magnon interaction effects and enhanced inelastic light scattering in
the strong-coupling regime, fulfilling a triple-resonance condition, are
analyzed and the limitations of the quasistatic adiabatic approximation are
established.",1904.10714v1
2019-09-25,Not quite black holes at LIGO,"We provide more evidence of not quite black holes at LIGO. We update and
streamline our previous search strategy and apply it to the ten black hole
merger events and the one neutron star merger event. The strategy is aimed at
the evenly spaced resonance spectrum expected from not quite black holes, given
that at low frequencies the radial wave equation describes the modes of a
stretched 1D cavity. We describe various indications of the self-consistency of
the apparent signals across all events in the context of a simple theoretical
model. The merger with the largest final mass, spin and redshift, GW170729,
provides additional interesting support.",1909.11801v2
2022-05-04,The Faraday effect in magnetoplasmonic nanostructures with spatial modulation of magnetization,"The magneto-optical Faraday effect in the magnetoplasmonic nanostructures
with nonuniform, periodically modulated spatial distribution of the
magnetization is considered. It is shown that in such nanostructures the
Faraday effect can experience the resonant enhancement in the spectral range of
the plasmonic and waveguide optical modes excitation. It happens both for $s$
and $p$-polarized light. Such an effect can serve for the spectrally selective
detection of the short spin waves in the magnetic materials.",2205.02020v1
2023-12-05,Interplay between magnetism and superconductivity in a hybrid magnon-photon bilayer system,"Spin waves in magnetic films are affected by the vicinity to a
superconductor. Here we studied a bilayer stack made of an insulating Yttrium
Iron Garnet (YIG) film and a high-$T_c$ YBCO superconducting planar resonator.
We investigated the hybridization of magnon and photon modes reporting the
temperature evolution of microwave transmission spectra. Data analysis, based
on the description of magnon modes and on the Hopfield model, shows that the
magnon-photon coupling strength and the mode frequency shift can be ultimately
related to the temperature dependence of the penetration depth of YBCO.",2312.02785v2
2016-06-08,"Breaking the rotating wave approximation for a strongly-driven, dressed, single electron spin","We investigate the dynamics of a strongly-driven, microwave-dressed,
donor-bound electron spin qubit in silicon. A resonant oscillating magnetic
field $B_1$ is used to dress the electron spin and create a new quantum system
with a level splitting proportional to $B_1$. The dressed two-level system can
then be driven by modulating the detuning $\Delta\nu$ between the microwave
source frequency $\nu_{\rm MW}$ and the electron spin transition frequency
$\nu_e$ at the frequency of the level splitting. The resulting dressed qubit
Rabi frequency $\Omega_{R\rho}$ is defined by the modulation amplitude, which
can be made comparable to the level splitting using frequency modulation on the
microwave source. This allows us to investigate the regime where the rotating
wave approximation breaks down, without requiring microwave power levels that
would be incompatible with a cryogenic environment. We observe clear deviations
from normal Rabi oscillations and can numerically simulate the time evolution
of the states in excellent agreement with the experimental data.",1606.02380v2
2022-10-04,Total angular momentum of water molecule and magnetic field interaction,"One of the must important non-invasive techniques in medicine is the Magnetic
Resonance Imaging (MRI), it is used to obtain information of the structure of
the human body parts using three dimensional images. The technique to obtain
these images is based by the emission of radio waves produced by the protons of
the hydrogen atoms in water molecules when placed in a constant magnetic field
after they interact with a pulsed radio frequency (RF) current, the spin of the
protons are in a spin excited state. When the RF field is turned off, the MRI
sensors are able to detect the energy released (RF waves) as the protons
realign their spins with the magnetic field.
  We used a three particles model for the water molecule: the two protons from
the hydrogen atoms move around the doubly negatively charged oxygen
(unstructured), to describe the total angular momentum. The energy levels from
the water molecule are studied in presence of an uniform external magnetic
field, which interacts with the proton's spin and orbital angular momentum. The
energy is shifted and the degeneration is lifted. To illustrate the results, we
provide numerical results for a magnetic field strength commonly used in MRI
devices.",2210.01867v1
2006-08-18,Electric Dipole Spin Resonance for Heavy Holes in Quantum Dots,"We propose and analyze a new method for manipulation of a heavy hole spin in
a quantum dot. Due to spin-orbit coupling between states with different orbital
momenta and opposite spin orientations, an applied rf electric field induces
transitions between spin-up and spin-down states. This scheme can be used for
detection of heavy-hole spin resonance signals, for the control of the spin
dynamics in two-dimensional systems, and for determining important parameters
of heavy-holes such as the effective $g$-factor, mass, spin-orbit coupling
constants, spin relaxation and decoherence times.",0608410v1
2007-01-23,Resonant spin polarization and spin current in a two-dimensional electron gas,"We study the spin polarization and its associated spin-Hall current due to
EDSR in disordered two-dimensional electron systems. We show that the disorder
induced damping of the resonant spin polarization can be strongly reduced by an
optimal field configuration that exploits the interference between Rashba and
Dresselhaus spin-orbit interaction. This leads to a striking enhancement of the
spin susceptibility while the spin-Hall current vanishes at the same time. We
give an interpretation of the spin current in geometrical terms which are
associated with the trajectories the polarization describes in spin space.",0701559v2
2012-04-26,Higher Order Spin Resonances in a 2.1 GeV/c Polarized Proton Beam,"Spin resonances can depolarize or spin-flip a polarized beam. We studied 1st
and higher order spin resonances with stored 2.1 GeV/c vertically polarized
protons. The 1st order vertical ({\nu}y) resonance caused almost full
spin-flip, while some higher order {\nu}y resonances caused partial
depolarization. The 1st order horizontal ({\nu}x) resonance caused almost full
depolarization, while some higher order {\nu}x resonances again caused partial
depolarization. Moreover, a 2nd order {\nu}x resonance is about as strong as
some 3rd order {\nu}x resonances, while some 3rd order {\nu}y resonances are
much stronger than a 2nd order {\nu}y resonance. One thought that {\nu}y spin
resonances are far stronger than {\nu}x, and that lower order resonances are
stronger than higher order; the data do not support this.",1204.6002v1
1996-01-11,The Three-Wave Resonant Interaction: Deformation of the Plane-Wave Solutions and Darboux Transformations,"The plane wave solutions of the three-wave resonant interaction in the plane
are considered. It is shown that rank-one constraints over the right
derivatives of invertible operators on an arbitrary linear space gives
solutions of the three-wave resonant interaction that can be understood as a
Darboux transformation of the plane wave solutions. The method is extended
further to obtain general Darboux transformations: for any solution of the
three-wave interaction problem and vector solutions of the corresponding Lax
pair large families of new solutions, expressed in terms of Grammian type
determinants of these vector solutions, are given.",9601002v1
2022-10-31,A Wave Packet Approach to Resonant Scattering,"Resonant transmission occurs when constructive interference results in the
complete passage of an incoming wave through an array of barriers. In this
paper we explore such a scenario with one dimensional models. We adopt wave
packets with finite width to illustrate the deterioration of resonance with
decreasing wave packet width, and suggest an approximate wave function for the
transmitted and reflected components, derived from aspects of both the wave
packet and plane wave approaches. A comparison with exact numerical
calculations shows excellent agreement, and provides insight into the
scattering process.",2210.17033v1
2018-02-05,Realization of a spin wave switch based on the Spin-Transfer-Torque effect,"We investigate the amplification of externally excited spin waves via the
Spin-Transfer-Torque (STT) effect in combination with the Spin-Hall-Effect
(SHE) employing short current pulses. The results reveal that, in the case of
an overcompensation of the spin wave damping, a strong nonlinear shift of the
spin wave frequency spectrum occurs. In particular, this shift affects the spin
wave amplification using the SHE-STT effect. In contrast, this effect allows
for the realization of a spin wave switch. By determining the corresponding
working point, an efficient spin wave excitation is only possible in the
presence of the SHE-STT effect yielding an increased spin wave intensity of a
factor of 20 compared to the absence of the SHE-STT effect.",1802.01294v1
2022-02-10,Amplifying spin waves along Néel domain wall by spin-orbit torque,"Traveling spin waves in magnonic waveguides undergo severe attenuation, which
tends to result in a finite propagation length of spin waves, even in magnetic
materials with the accessible lowest damping constant, heavily restricting the
development of magnonic devices. Compared with the spin waves in traditional
waveguides, propagating spin waves along strip domain wall are expected to
exhibit enhanced transmission. Here, we demonstrate, theoretically and through
micromagnetic simulations, that spin-orbit torque associated with a
ferromagnet/heavy metal bilayer can efficiently control the attenuation of spin
waves along a N\'eel-type strip domain wall, despite the complexity in the
ground-state magnetization configuration. The direction of the electric current
applied to the heavy-metal layer determines whether these spin waves are
amplified or further attenuated otherwise. Remarkably, our simulations reveal
that the effective current densities required to efficiently tune the decay of
such spin waves are just ~10^10 Am-2, roughly an order smaller than those
required in conventional spin waveguides. Our results will enrich the toolset
for magnonic technologies.",2202.05181v1
2003-04-10,Full quantum solutions to the resonant four-wave mixing of two single-photon wave packets,"We analyze both analytically and numerically the resonant four-wave mixing of
two co-propagating single-photon wave packets. We present analytic expressions
for the two-photon wave function and show that soliton-type quantum solutions
exist which display a shape-preserving oscillatory exchange of excitations
between the modes. Potential applications including quantum information
processing are discussed.",0304072v1
2019-10-09,Thermally controlled confinement of spin wave field in a magnonic YIG waveguide,"Methods for detecting spin waves rely on electrodynamical coupling between
the spin wave dipolar field and an inductive probe. While this coupling is
usually treated as constant, in this work, we experimentally and theoretically
show that it is indeed temperature dependent. By measuring the spin wave
magnetic field as a function of temperature of, and distance to the sample, we
demonstrate that there is both a longitudinal and transversal confinement of
the field near the YIG-Air interface. Our results are relevant for spin wave
detection, in particular in the field of spin wave caloritronics",1910.04304v1
1999-05-17,Parametric resonant acceleration of particles by gravitational waves,"We study the resonant interaction of charged particles with a gravitational
wave propagating in the non-empty interstellar space in the presence of a
uniform magnetic field. It is found that this interaction can be cast in the
form of a parametric resonance problem which, besides the main resonance,
allows for the existence of many secondary ones. Each of them is associated
with a non-zero resonant width, depending on the amplitude of the wave and the
energy density of the interstellar plasma. Numerical estimates of the
particles' energisation and the ensuing damping of the wave are given.",9905054v1
2006-07-13,Resonant transparency of materials with negative permittivity,"It is shown that the transparency of opaque material with negative
permittivity exhibits resonant behavior. The resonance occurs as a result of
the excitation of the surface waves at slab boundaries. Dramatic field
amplification of the incident evanescent fields at the resonance improves the
resolution of the the sub-wavelength imaging system (superlens). A finite
thickness slab can be totally transparent to a \textit{p}-polarized obliquely
incident electromagnetic wave for certain values of the incidence angle and
wave frequency corresponding to the excitation of the surface modes. At the
resonance, two evanescent waves have a finite phase shift providing non-zero
energy flux through the non-transparent region.",0607130v1
2009-03-27,Effect of non-zero constant vorticity on the nonlinear resonances of capillary water waves,"The influence of an underlying current on 3-wave interactions of capillary
water waves is studied. The fact that in irrotational flow resonant 3-wave
interactions are not possible can be invalidated by the presence of an
underlying current of constant non-zero vorticity. We show that: 1) wave trains
in flows with constant non-zero vorticity are possible only for two-dimensional
flows; 2) only positive constant vorticities can trigger the appearance of
three-wave resonances; 3) the number of positive constant vorticities which do
trigger a resonance is countable; 4) the magnitude of a positive constant
vorticity triggering a resonance can not be too small.",0903.4813v1
2013-09-18,Spin polarization oscillations without spin precession: spin-orbit entangled resonances in quasi-one-dimensional spin transport,"Resonant behavior involving spin-orbit entangled states occurs for spin
transport along a narrow channel defined in a two-dimensional electron gas,
including an apparent rapid relaxation of the spin polarization for special
values of the channel width and applied magnetic field (so-called ballistic
spin resonance). A fully quantum mechanical theory for transport through
multiple subbands of the one-dimensional system provides the dependence of the
spin transport on the applied magnetic field and channel width, including a
resonant depolarization of spins when the Zeeman energy matches the subband
energy splittings and a spin texture transverse to the magnetic field. The
resonance phenomenon is robust to disorder.",1309.4509v1
2019-03-03,Optically detected spin-mechanical resonance in silicon carbide membranes,"Hybrid spin-mechanical systems are a promising platform for future quantum
technologies. Usually they require application of additional microwave fields
to project integer spin to a readable state. We develop a theory of optically
detected spin-mechanical resonance associated with half-integer spin defects in
silicon carbide (SiC) membranes. It occurs when a spin resonance frequency
matches a resonance frequency of a mechanical mode, resulting in a shortening
of the spin relaxation time through resonantly enhanced spin-phonon coupling.
The effect can be detected as an abrupt reduction of the photoluminescence
intensity under optical pumping without application of microwave fields. We
propose all-optical protocols based on such spin-mechanical resonance to detect
external magnetic fields and mass with ultra-high sensitivity. We also discuss
room-temperature nonlinear effects under strong optical pumping, including
spin-mediated cooling and heating of mechanical modes. Our approach suggests a
new concept for quantum sensing using spin-optomechanics.",1903.00876v1
2005-09-06,Strong Resonance of Light in a Cantor Set,"The propagation of an electromagnetic wave in a one-dimensional fractal
object, the Cantor set, is studied. The transfer matrix of the wave amplitude
is formulated and its renormalization transformation is analyzed. The focus is
on resonant states in the Cantor set. In Cantor sets of higher generations,
some of the resonant states closely approach the real axis of the wave number,
leaving between them a wide region free of resonant states. As a result, wide
regions of nearly total reflection appear with sharp peaks of the transmission
coefficient beside them. It is also revealed that the electromagnetic wave is
strongly enhanced and localized in the cavity of the Cantor set near the
resonant frequency. The enhancement factor of the wave amplitude at the
resonant frequency is approximately $6/|\eta_\mathrm{r}|$, where
$\eta_\mathrm{r}$ is the imaginary part of the corresponding resonant
eigenvalue. For example, a resonant state of the lifetime
$\tau_\mathrm{r}=4.3$ms and of the enhancement factor $M=7.8\times10^7$ is
found at the resonant frequency $\omega_\mathrm{r}=367$GHz for the Cantor set
of the fourth generation of length L=10cm made of a medium of the dielectric
constant $\epsilon=10$.",0509145v1
2009-05-01,Nonlinear resonances of water waves,"In the last fifteen years, a great progress has been made in the
understanding of the nonlinear resonance dynamics of water waves. Notions of
scale- and angle-resonances have been introduced, new type of energy cascade
due to nonlinear resonances in the gravity water waves have been discovered,
conception of a resonance cluster has been much and successful employed, a
novel model of laminated wave turbulence has been developed, etc. etc. Two
milestones in this area of research have to be mentioned: a) development of the
$q$-class method which is effective for computing integer points on the
resonance manifolds, and b) construction of the marked planar graphs, instead
of classical resonance curves, representing simultaneously all resonance
clusters in a finite spectral domain, together with their dynamical systems.
Among them, new integrable dynamical systems have been found that can be used
for explaining numerical and laboratory results. The aim of this paper is to
give a brief overview of our current knowledge about nonlinear resonances among
water waves, and formulate three most important open problems at the end.",0905.0050v2
2008-10-28,Quantization Of Spin Direction For Solitary Waves In A Uniform Magnetic Field,"It is known that there are nonlinear wave equations with localized solitary
wave solutions. Some of these solitary waves are stable (with respect to a
small perturbation of initial data) and have nonzero spin (nonzero intrinsic
angular momentum in the center of momentum frame). In this paper we consider
vector-valued solitary wave solutions to a nonlinear Klein-Gordon equation and
investigate the behavior of these spinning solitary waves under the influence
of an externally imposed uniform magnetic field. We find that the only
stationary spinning solitary wave solutions have spin parallel or anti-parallel
to the magnetic field direction.",0810.4959v2
2020-09-28,Rolling Waves with Non-Paraxial Phonon Spins,"We demonstrate a new class of elastic waves in the bulk: When longitudinal
and transverse components propagate at the same speed, rolling waves with a
spin that is not parallel to the wave vector can emerge. First, we give a
general definition of spin for traveling waves. Then, since rolling waves
cannot exist in isotropic solids, we derive conditions for anisotropic media
and proceed to design architected materials capable of hosting rolling waves.
Numerically, we show spin manipulations by reflection. Structures reported in
this work can be fabricated using available techniques, opening new
possibilities for spin technologies in acoustics, mechanics and phononics.",2009.13014v1
2018-03-20,Detection and characterization of spin-orbit resonances in the advanced gravitational wave detectors era,"In this paper, we test the performance of templates in detection and
characterization of Spin-orbit resonant (SOR) binaries. We use precessing
SEOBNRv3 waveforms as well as {\it four} numerical relativity (NR) waveforms to
model GWs from SOR binaries and filter them through IMRPhenomD, SEOBNRv4
(non-precessing) and IMRPhenomPv2 (precessing) approximants. We find that
IMRPhenomD and SEOBNRv4 recover only $\sim70\%$ of injections with fitting
factor (FF) higher than 0.97 (or 90\% of injections with ${\rm FF}
>0.9$).However, using the sky-maxed statistic, IMRPhenomPv2 performs
magnificently better than their non-precessing counterparts with recovering
$99\%$ of the injections with FFs higher than 0.97. Interestingly, injections
with $\Delta \phi = 180^{\circ}$ have higher FFs ($\Delta \phi$ is the angle
between the components of the black hole spins in the plane orthogonal to the
orbital angular momentum) as compared to their $\Delta \phi =0^{\circ}$ and
generic counterparts. This implies that we will have a slight observation bias
towards $\Delta \phi=180^{\circ}$ SORs while using non-precessing templates for
searches. All template approximants are able to recover most of the injected NR
waveforms with FFs $>0.95$. For all the injections including NR, the error in
estimating chirp mass remains below $<10\%$ with minimum error for $\Delta \phi
= 180^{\circ}$ resonant binaries. The symmetric mass ratio can be estimated
with errors below $15\%$. The effective spin parameter $\chi_{\rm eff}$ is
measured with maximum absolute error of 0.13. The in-plane spin parameter
$\chi_p$ is mostly underestimated indicating that a precessing signal will be
recovered as a relatively less precessing signal. Based on our findings, we
conclude that we not only need improvements in waveform models towards
precession and non-quadrupole modes but also better search strategies for
precessing GW signals.",1803.07695v2
2021-12-27,Spin-electron-acoustic waves and solitons in high-density degenerate relativistic plasmas,"The spin-electron-acoustic waves (sometimes called the spin-plasmons) can be
found in degenerate electron gas if the spin-up electrons and spin down
electrons move relatively each other. Here, we suggest relativistic
hydrodynamics with the separate spin evolution which allows us to study linear
and nonlinear spin-electron-acoustic waves, including the
spin-electron-acoustic solitons. Presented hydrodynamic model is the
corresponding generalization of the relativistic hydrodynamic model with the
average reverse gamma factor evolution which consists of the equations for
evolution of the following functions the partial concentrations (for spin-up
electrons and spin down electrons), the partial velocity fields, the partial
average reverse relativistic gamma factors, and the partial flux of the reverse
relativistic gamma factors. We find that the relativistic effects decreases the
phase velocity of spin-electron-acoustic waves. Numerical analysis of the
changes of spectra of Langmuir wave, spin-electron-acoustic wave, and
ion-acoustic wave under the change of the spin polarization of electrons is
presented. It is demonstrated that spectra of Langmuir wave and
spin-electron-acoustic wave getting closer to each other in the relativistic
limit. Spin dependence of the amplitude and width of the relativistic
spin-electron-acoustic soliton is demonstrated as well. Reformation of the
bright soliton of potential of the electric field into the dark soliton under
the influence of the relativistic effects is found.",2112.13880v1
2016-04-13,Coherent electron-spin-resonance manipulation of three individual spins in a triple quantum dot,"Quantum dot arrays provide a promising platform for quantum information
processing. For universal quantum simulation and computation, one central issue
is to demonstrate the exhaustive controllability of quantum states. Here, we
report the addressable manipulation of three single electron spins in a triple
quantum dot using a technique combining electron-spin-resonance and a
micro-magnet. The micro-magnet makes the local Zeeman field difference between
neighboring spins much larger than the nuclear field fluctuation, which ensures
the addressable driving of electron-spin-resonance by shifting the resonance
condition for each spin. We observe distinct coherent Rabi oscillations for
three spins in a semiconductor triple quantum dot with up to 25 MHz spin
rotation frequencies. This individual manipulation over three spins enables us
to arbitrarily change the magnetic spin quantum number of the three spin
system, and thus to operate a triple-dot device as a three-qubit system in
combination with the existing technique of exchange operations among three
spins.",1604.03658v1
2013-07-29,Current-induced spin wave excitation in Pt|YIG bilayer,"We develop a self-consistent theory for current-induced spin wave excitations
in normal metal-magnetic insulator bilayer systems, thereby establishing the
relation between spin wave excitation and the experimentally controlled
parameters. We fully take into account the complex spin wave spectrum including
dipolar interactions and surface anisotropy as well as the spin-pumping at the
interface. Our results focus on the mode-dependent power close to the critical
currents for spin wave excitation. The major findings are (a) the spin transfer
torque can excite different spin-wave modes simultaneously; (b) spin pumping
counterbalances spin-transfer torque and affects the surface modes more than
the bulk modes; (c) spin pumping inhibits high frequency spin-wave modes,
thereby redshifting the excitation spectrum. We can get agreement with
experiments on yttrium iron garnet|platinum bilayers by postulating the
existence of surface anisotropy modes.",1307.7607v2
2008-03-29,Quantized spin waves and perpendicular standing spin waves stimulated by current in a single-layered ferromagnetic wire,"The rectifying effect of radio-frequency (RF) current is highly sensitive in
terms of the spatial spin distribution and dynamics. It emerged that an
additional spin wave mode was stimulated by the direct-current (DC) current and
that this spin wave was detectable via rectification of the RF current. A
phenomenological model to describe the time-dependent anisotropic
magnetoresistance or time-dependent planer Hall effect is proposed and found to
correlate well to the experimental results. The nonlinear spin dynamics
accompanying additional spin waves are studied as functions of the RF and DC
currents, the external magnetic field, and the applied field direction.",0803.4271v1
2011-07-04,Comparative studies of the scanning tunneling spectra in cuprate and iron-arsenide superconductors,"We report scanning tunneling spectroscopic studies of cuprate and
iron-arsenic superconductors, including YBa_2Cu_3O_{7-\delta} (Y-123, T_c = 93
K), Sr_{0.9}La_{0.1}CuO_2 (La-112, T_c = 43 K), and the ""122"" compounds
Ba(Fe_{1-x}Co_x)_2As_2 (Co-122 with x = 0.06, 0.08, 0.12 for T_c = 14, 24, 20
K). For H > 0, pseudogap (\Delta_{PG}) features are revealed inside the
vortices, with \Delta_{PG} = [(\Delta_{eff})^2+(\Delta_{SC})^2]^{1/2} >
\Delta_{SC} in Y-123 and \Delta_{PG} < \Delta_{SC} in La-112, suggesting that
the physical origin of \Delta_{PG} is a competing order coexisting with
superconductivity. Additionally, Fourier transformation (FT) of the Y-123
spectra exhibits two types of spectral peaks, one type is associated with
energy (\omega)-dependent quasiparticle interference (QPI) wave-vectors and the
other consists of \omega-independent wave-vectors due to competing orders and
(\pi,\pi) magnetic resonances. For the multi-band Co-122 compounds, two-gap
superconductivity is found for all doping levels. Magnetic resonant modes that
follow the temperature dependence of the superconducting gaps are also
identified. These findings, together with the \omega- and x-dependent QPI
spectra, are consistent with a sign-changing s-wave pairing symmetry in the
Co-122 iron arsenides. Our comparative studies suggest that the commonalities
among the cuprate and the ferrous superconductors include the proximity to
competing orders, antiferromagnetic (AFM) spin fluctuations and magnetic
resonances in the superconducting (SC) state, and the unconventional pairing
symmetries with sign-changing order parameters on different parts of the Fermi
surface.",1107.0697v1
2012-01-30,Dirac Hamiltonian with Imaginary Mass and Induced Helicity-Dependence by Indefinite Metric,"It is of general theoretical interest to investigate the properties of
superluminal matter wave equations for spin one-half particles. One can either
enforce superluminal propagation by an explicit substitution of the real mass
term for an imaginary mass, or one can use a matrix representation of the
imaginary unit that multiplies the mass term. The latter leads to the tachyonic
Dirac equation, while the equation obtained by the substitution m->i*m in the
Dirac equation is naturally referred to as the imaginary-mass Dirac equation.
Both the tachyonic as well as the imaginary-mass Dirac Hamiltonians commute
with the helicity operator. Both Hamiltonians are pseudo-Hermitian and also
possess additional modified pseudo-Hermitian properties, leading to constraints
on the resonance eigenvalues. Here, by an explicit calculation, we show that
specific sum rules over the spectrum hold for the wave functions corresponding
to the well-defined real energy eigenvalues and complex resonance and
anti-resonance energies. In the quantized imaginary-mass Dirac field,
one-particle states of right-handed helicity acquire a negative norm
(""indefinite metric"") and can be excluded from the physical spectrum by a
Gupta--Bleuler type condition.",1201.6300v4
2018-12-11,"""Cartesian light"": unconventional propagation of light in a 3D superlattice of coupled cavities within a 3D photonic band gap","We explore the unconventional propagation of light in a three-dimensional
(3D) superlattice of coupled resonant cavities in a 3D photonic band gap
crystal. Such a 3D cavity superlattice is the photonic analogue of the Anderson
model for spins and electrons in the limit of zero disorder. Using the
plane-wave expansion method, we calculate the dispersion relations of the 3D
cavity superlattice with the cubic inverse woodpile structure that reveal five
coupled-cavity bands, typical of quadrupole-like resonances. For three out of
five bands, we observe that the dispersion bandwidth is significantly larger in
the $(k_x, k_z)$-diagonal directions than in other directions. To explain the
directionality of the dispersion bandwidth, we employ the tight-binding method
from which we derive coupling coefficients in 3D. For all converged
coupled-cavity bands, we find that light hops predominantly in a few
high-symmetry directions including the Cartesian $(x, y, z)$ directions,
therefore we propose the name ""Cartesian light"". Such 3D Cartesian hopping of
light in a band gap yields propagation as superlattice Bloch modes that differ
fundamentally from the conventional 3D spatially-extended Bloch wave
propagation in crystals, from light tunneling through a band gap, from
coupled-resonator optical waveguiding, and also from light diffusing at the
edge of a gap.",1812.04472v1
2019-04-18,Excitation of the electric pygmy dipole resonance by inelastic electron scattering,"To complete earlier studies of the properties of the electric pygmy dipole
resonance (PDR) obtained in various nuclear reactions, the excitation of the
1$^-$ states in $^{140}$Ce by $(e,e')$ scattering for momentum transfers
$q=0.1-1.2$~fm$^{-1}$ is calculated within the plane-wave and distorted-wave
Born approximations. The excited states of the nucleus are described within the
Quasiparticle Random Phase Approximation (QRPA), but also within the
Quasiparticle-Phonon Model (QPM) by accounting for the coupling to complex
configurations. It is demonstrated that the excitation mechanism of the PDR
states in $(e,e')$ reactions is predominantly of transversal nature for
scattering angles $\theta_e \approx 90^o-180^o$. Being thus mediated by the
convection and spin nuclear currents, the $(e,e')$ like the $(\gamma,\gamma')$
reaction, may provide additional information to the one obtained from Coulomb-
and hadronic excitations of the PDR in $(p,p')$, $(\alpha,\alpha')$, and
heavy-ion scattering reactions. The calculations predict that the $(e,e')$
cross sections for the strongest individual PDR states are in general about
three orders of magnitude smaller as compared to the one of the lowest $2^+_1$
state for the studied kinematics, but that they may become dominant at extreme
backward angles.",1904.08772v1
2010-04-14,Measurement of magnetic excitations in the two-dimensional antiferromagnetic Sr2CuO2Cl2 insulator using resonant x-ray scattering:Evidence for extended interactions,"Using high-resolution resonant inelastic x-ray scattering (RIXS), we
performed a momentum-resolved study of magnetic excitations in the model
spin-1/2 2D antiferromagnetic insulator Sr_2CuCl_2O_2. We identify both a
single-spin-wave feature and a multi-magnon continuum, and show that the X-ray
polarization can be used to distinguish these two contributions in the
cross-section. The spin-waves display a large (70 meV) dispersion between the
zone-boundary points ($\pi$,0) and ($\pi$/2,$\pi$/2). Employing an extended
$t$-$t'$-$t""$-$U$ one-band Hubbard model, we find significant electronic
hopping beyond nearest-neighbor Cu ions. We conclude that sizeable extended
magnetic interactions are present in \scoc{} and probably important in all
undoped cuprates.",1004.2441v3
2011-02-11,Quasiparticle states around a nonmagnetic impurity in electron-doped iron-based superconductors with spin-density-wave order,"The quasiparticle states around a nonmagnetic impurity in electron-doped
iron-based superconductors with spin-density-wave (SDW) order are investigated
as a function of doping and impurity scattering strength. In the undoped
sample, where a pure SDW state exists, two impurity-induced resonance peaks are
observed around the impurity site and they are shifted to higher (lower)
energies as the strength of the positive (negative) scattering potential (SP)
is increased. For the doped samples where the SDW order and the superconducting
order coexist, the main feature is the existence of sharp in-gap resonance
peaks whose positions and intensity depend on the strength of the SP and the
doping concentration. In all cases, the local density of states exhibits clear
$C_2$ symmetry. We also note that in the doped cases, the impurity will divide
the system into two sublattices with distinct values of magnetic order. Here we
use the band structure of a two-orbital model, which considers the asymmetry of
the As atoms above and below the Fe-Fe plane. This model is suitable to study
the properties of the surface layers in the iron-pnictides and should be more
appropriate to describe the scanning tunneling microscopy experiments.",1102.2401v1
2015-03-02,Coexistence of multiple charge-density waves and superconductivity in SrPt2As2 revealed by 75As-NMR/NQR and 195Pt-NMR,"The relationship between charge density wave (CDW) orders and
superconductivity in arsenide superconductor SrPt$_2$As$_2$ with $T_c$ = 5.2 K
which crystallizes in the CaBe$_2$Ge$_2$-type structure was studied by
$^{75}$As nuclear magnetic resonance (NMR) measurements up to 520 K, and
$^{75}$As nuclear quadrupole resonance (NQR) and $^{195}$Pt-NMR measurements
down to 1.5 K. At high temperature, $^{75}$As-NMR spectrum and nuclear spin
relaxation rate ($1/T_1$) have revealed two distinct CDW orders, one realized
in the As-Pt-As layer below $T_{\rm CDW}^{\rm As(1)}$ $=$ 410 K and the other
in the Pt-As-Pt layer below $T_{\rm CDW}^{\rm As(2)}$ $=$ 255 K. The $1/T_1$
measured by $^{75}$As-NQR shows a clear Hebel-Slichter peak just below $T_c$
and decreases exponentially well below $T_c$. Concomitantly, $^{195}$Pt Knight
shift decreases below $T_c$. Our results indicate that superconductivity in
SrPt$_2$As$_2$ is in the spin-singlet state with an $s$-wave gap and is robust
under the two distinct CDW orders in different layers.",1503.00512v1
2016-05-11,Classification of trivial spin-1 tensor network states on a square lattice,"Classification of possible quantum spin liquid (QSL) states of interacting
spin-1/2's in two dimensions has been a fascinating topic of condensed matter
for decades, resulting in enormous progress in our understanding of
low-dimensional quantum matter. By contrast, relatively little work exists on
the identification, let alone classification, of QSL phases for spin-1 systems
in dimensions higher than one. Employing the powerful ideas of tensor network
theory and its classification, we develop general methods for writing QSL wave
functions of spin-1 respecting all the lattice symmetries, spin rotation, and
time reversal with trivial gauge structure on the square lattice. We find $2^5$
distinct classes characterized by five binary quantum numbers. Several explicit
constructions of such wave functions are given for bond dimensions $D$ ranging
from two to four, along with thorough numerical analyses to identify their
physical characters. Both gapless and gapped states are found. The topological
entanglement entropy of the gapped states are close to zero, indicative of
topologically trivial states. In $D=4$, several different tensors can be
linearly combined to produce a family of states within the same symmetry class.
A rich ""phase diagram"" can be worked out among the phases of these tensors, as
well as the phase transitions among them. Among the states we identified in
this putative phase diagram is the plaquette-ordered phase, gapped resonating
valence bond phase, and a critical phase. A continuous transition separates the
plaquette-ordered phase from the resonating valence bond phase.",1605.03274v1
2016-10-26,Resonant inelastic X-ray scattering study of spin-wave excitations in the cuprate parent compound Ca$_{2}$CuO$_2$Cl$_2$,"By means of resonant inelastic x-ray scattering at the Cu L$_3$ edge, we
measured the spin wave dispersion along $\langle$100$\rangle$ and
$\langle$110$\rangle$ in the undoped cuprate Ca$_2$CuO$_2$Cl$_2$. The data
yields a reliable estimate of the superexchange parameter $J$ = 135 $\pm$ 4 meV
using a classical spin-1/2 2D Heisenberg model with nearest-neighbor
interactions and including quantum fluctuations. Including further exchange
interactions increases the estimate to $J$ = 141 meV. The 40 meV dispersion
between the magnetic Brillouin zone boundary points (1/2,\,0) and (1/4,\,1/4)
indicates that next-nearest neighbor interactions in this compound are
intermediate between the values found in La$_{2}$CuO$_4$ and
Sr$_2$CuO$_2$Cl$_2$. Owing to the low-$Z$ elements composing
Ca$_2$CuO$_2$Cl$_2$, the present results may enable a reliable comparison with
the predictions of quantum many-body calculations, which would improve our
understanding of the role of magnetic excitations and of electronic
correlations in cuprates.",1610.08383v5
2020-03-24,Epitaxial bulk acoustic wave resonators as highly coherent multi-phonon sources for quantum acoustodynamics,"Solid-state quantum acoustodynamic (QAD) systems provide a compact platform
for quantum information storage and processing by coupling acoustic phonon
sources with superconducting or spin qubits. The multi-mode composite
high-overtone bulk acoustic wave resonator (HBAR) is a popular phonon source
well suited for QAD. However, scattering from defects, grain boundaries, and
interfacial/surface roughness in the composite transducer severely limits the
phonon relaxation time in sputter-deposited devices. Here, we grow an
epitaxial-HBAR, consisting of a metallic NbN bottom electrode and a
piezoelectric GaN film on a SiC substrate. The acoustic impedance-matched
epi-HBAR has a power injection efficiency > 99% from transducer to phonon
cavity. The smooth interfaces and low defect density reduce phonon losses,
yielding fxQ products and phonon lifetimes up to 1.36 x 10^17 Hz and 500
microseconds respectively. The GaN/NbN/SiC epi-HBAR is an electrically
actuated, multi-mode phonon source that can be directly interfaced with
NbN-based superconducting qubits or SiC-based spin qubits.",2003.11097v1
2020-03-28,Acoustic Wave Induced FMR Assisted Spin-Torque Switching of Perpendicular MTJs with Anisotropy Variation,"We have investigated Surface Acoustic Wave (SAW) induced ferromagnetic
resonance (FMR) assisted Spin Transfer Torque (STT) switching of perpendicular
MTJ (p-MTJ) with inhomogeneities using micromagnetic simulations that include
the effect of thermal noise. With suitable frequency excitation, the SAW can
induce ferromagnetic resonance in magnetostrictive materials, and the
magnetization can precesses in a cone with high deflection from the
perpendicular direction. With incorporation of inhomogeneity via lateral
anisotropy variation as well as room temperature thermal noise, the
magnetization precession in different gains can be significantly incoherent.
Interestingly, the precession in different grains are found to be in phase,
even though the precession amplitude (angle of deflection from the
perpendicular direction) vary across grains of different anisotropy.
Nevertheless, the high mean deflection angle can complement the STT switching
by reducing the STT current significantly; even though the applied stress
induced change in anisotropy is much lower than the total anisotropy barrier.
This work indicates that SAW assisted switching can improve energy efficiency
while being scalable to very small dimensions, which is technologically
important for STT-RAM and elucidates the physical mechanism for the potential
robustness of this paradigm in realistic scenarios with thermal noise and
material inhomogeneity",2003.12903v1
2021-09-07,Photoluminescence and Electron Spin Resonance of Silicon Dioxide Crystal with Rutile Structure (Stishovite),"An electron spin resonance (ESR) and photoluminescence signal is observed in
the as grown single crystal of stishovite indicating the presence of defects in
the non-irradiated sample. Photoluminescence of the as received stishovite
single crystals exhibits two main bands - a blue at 3 eV and an UV at 4.75 eV.
Luminescence is excited in the range of optical transparency of stishovite
(below 8.75 eV) and, therefore, is ascribed to defects. A wide range of decay
kinetics under a pulsed excitation is observed. For the blue band besides the
exponential decay with a time constant of about 18 {\mu}s an additional ms
component is revealed. For the UV band besides the fast component with a time
constant of 1-3 ns a component with a decay in tens {\mu}s is obtained. The
main components (18 {\mu}s and 1-3 ns) possess a typical intra-center
transition intensity thermal quenching. The effect of the additional slow
component is related to the presence of OH groups and/or carbon molecular
defects modifying the luminescence center. The additional slow components
exhibit wave-like thermal dependences. Photo-thermally stimulated
creation-destruction of complex comprising host defect - interstitial modifiers
explains slow luminescence wave-like thermal dependences.",2109.03056v1
2023-02-22,Effect of dynamical gravitomagnetic tides on measurability of tidal parameters for binary neutron stars using gravitational waves,"Gravitational waves (GWs) from binary neutron stars (NSs) have opened unique
opportunities to constrain the nuclear equation of state by measuring tidal
effects associated with the excitation of characteristic modes of the NSs. This
includes gravitomagnetic modes associated with the Coriolis effect, whose
frequencies are proportional to the NS's spin frequency, and for which the spin
orientation determines the subclass of modes that are predominantly excited. We
advance the GW models for these effects that are needed for data analysis by
first developing a description for the adiabatic signatures from
gravitomagnetic modes in slowly rotating NSs. We show that they can be
encapsulated in an effective Love number which differs before and after a mode
resonance. Combining this with a known generic model for abrupt changes in the
GWs at the mode resonance and a point-mass baseline leads to an efficient
description which we use to perform case studies of the impacts of
gravitomagnetic effects for measurements with Cosmic Explorer, an envisioned
next-generation GW detector. We quantify the extent to which neglecting
(including) the effect of gravitomagnetic modes induces biases (significantly
reduces statistical errors) in the measured tidal deformability parameters,
which depend on the equation of state. Our results substantiate the importance
of dynamical gravitomagnetic tidal effects for measurements with third
generation detectors.",2302.11274v1
1999-05-04,Efficient Refocussing of One Spin and Two Spin Interactions for NMR Quantum Computation,"The use of spin echoes to refocus one spin interactions (chemical shifts) and
two spin interactions (spin-spin couplings) plays a central role in both
conventional NMR experiments and NMR quantum computation. Here we describe
schemes for efficient refocussing of such interactions in both fully and
partially coupled spin systems.",9905008v1
2008-12-13,Spin-Transfer Torque in Helical Spin-Density Waves,"The current driven magnetisation dynamics of a helical spin-density wave is
investigated. Expressions for calculating the spin-transfer torque of real
systems from first principles density functional theory are presented. These
expressions are used for calculating the spin-transfer torque for the spin
spirals of Er and fcc Fe at two different lattice volumes. It is shown that the
calculated torque induces a rigid rotation of the order parameter with respect
to the spin spiral axis. The torque is found to depend on the wave vector of
the spin spiral and the spin-polarisation of the Fermi surface states. The
resulting dynamics of the spin spiral is also discussed.",0812.2509v1
2016-06-28,Single Spin Magnetic Resonance,"Different approaches have improved the sensitivity of either electron or
nuclear magnetic resonance to the single spin level. For optical detection it
has essentially become routine to observe a single electron spin or nuclear
spin. Typically, the systems in use are carefully designed to allow for single
spin detection and manipulation, and of those systems, diamond spin defects
rank very high, being so robust that they can be addressed, read out and
coherently controlled even under ambient conditions and in a versatile set of
nanostructures. This renders them as a new type of sensor, which has been shown
to detect single electron and nuclear spins among other quantities like force,
pressure and temperature. Adapting pulse sequences from classic NMR and EPR,
and combined with high resolution optical microscopy, proximity to the target
sample and nanoscale size, the diamond sensors have the potential to constitute
a new class of magnetic resonance detectors with single spin sensitivity. As
diamond sensors can be operated under ambient conditions, they offer potential
application across a multitude of disciplines. Here we review the different
existing techniques for magnetic resonance, with a focus on diamond defect spin
sensors, showing their potential as versatile sensors for ultra-sensitive
magnetic resonance with nanoscale spatial resolution.",1606.08830v1
2020-01-16,Real-space imaging of atomic-scale spin textures at nanometer distances,"Spin-polarized scanning tunneling microscopy (SP-STM) experiments on
ultrathin films with non-collinear spin textures demonstrate that resonant
tunneling allows for atomic-scale spin-sensitive imaging in real space at
tip-sample distances of up to 8 nm. Spin-polarized resonance states evolving
between the foremost atom of a magnetic probe tip and the opposed magnetic
surface atom are found to provide a loophole from the hitherto existing dilemma
of losing spatial resolution when increasing the tip-sample distance in a
scanning probe setup. Bias-dependent series of SP-STM images recorded via
resonant tunneling reveal spin sensitivity at resonance conditions, indicating
that the spin-polarized resonance states act as mediators for the spin contrast
across the nm-spaced vacuum gap. With technically feasible distances in the nm
regime, resonant tunneling in SP-STM qualifies for a spin-sensitive read-write
technique with ultimate lateral resolution in future spintronic applications.",2001.05799v1
2019-10-17,Resonant Energization of Relativistic particles by an Intense Electromagnetic Wave,"The phenomenon of resonant energization of a relativistic quantum particle,
moving in unison with an intense ElectroMagnetic Wave, is demonstrated in a
semiclassical calculation. The wave nature of the quantum particle is of
essence because the resonant process originates in wave-wave
interaction-between the classical EM wave, and the quantum wave associated with
the particle. When the energy /momentum of the quantum wave satisfy the
resonance condition (the effective phase speeds of the two waves are equal),
the particle, drawing energy directly from the intense EM field, could acquire
extremely high energies Such a direct resonant energy transfer from intense
Electromagnetic waves will constitute a hitherto unexploited mechanism that
could power the most energetic of cosmic rays. Some predictions of the theory
will, hopefully, be tested in the laboratory Laser experiments.",1910.08147v1
2006-01-25,Spin-Dynamical Analysis of Supercell Spin Configurations,"A model-independent approach capable of extracting spin-wave frequencies and
displacement vectors from ensembles of supercell spin configurations is
presented. The method is appropriate for those systems whose spin-dynamical
motion is well characterised by small-amplitude fluctuations that give harmonic
spin waves. First, the the spin-dynamical matrix is described and its
eigenvalues shown to correspond to the spin-wave mode frequencies. The
generalised spin coordinate matrix - a quantity that may be calculated from the
observed spin orientations in an ensemble of spin configurations - is then
introduced and its relationship to the spin-dynamical matrix established. Its
eigenvalues are subsequently shown to be related to the spin-wave mode
frequencies, allowing the extraction of spin-wave dispersion curves from
configurational ensembles. Finally, a quantum-mechanical derivation of the same
results is given, and the method applied as a case study to spin Monte-Carlo
configurations of a 3D Heisenberg ferromagnet.",0601559v2
2020-03-09,On the gravitational waves coupled with electromagnetic waves,"A description is made of the process of excitation of coupled
longitudinal-transverse gravitational waves during the propagation of a strong
electromagnetic wave in a vacuum and when a standing electromagnetic wave
exists in the Fabry-Perot resonator. It is shown that such waves lead to the
appearance of transverse gravitational waves in empty space. It was established
that two standing high-frequency electromagnetic waves in a Fabry-Perot
resonator with close frequencies cause the appearance of a low-frequency
transverse gravitational wave in empty space.",2003.04104v1
2006-01-12,Phase transitions in the boson-fermion resonance model in one dimension,"We study 1D fermions with photoassociation or with a narrow Fano-Feshbach
resonance described by the Boson-Fermion resonance model. Using thebosonization
technique, we derive a low-energy Hamiltonian of the system. We show that at
low energy, the order parameters for the Bose Condensation and fermion
superfluidity become identical, while a spin gap and a gap against the
formation of phase slips are formed. As a result of these gaps, charge density
wave correlations decay exponentially in contrast with the phases where only
bosons or only fermions are present. We find a Luther-Emery point where the
phase slips and the spin excitations can be described in terms of
pseudofermions. This allows us to provide closed form expressions of the
density-density correlations and the spectral functions. The spectral functions
of the fermions are gapped, whereas the spectral functions of the bosons remain
gapless. The application of a magnetic field results in a loss of coherence
between the bosons and the fermion and the disappearance of the gap. Changing
the detuning has no effect on the gap until either the fermion or the boson
density is reduced to zero. Finally, we discuss the formation of a Mott
insulating state in a periodic potential. The relevance of our results for
experiments with ultracold atomic gases subject to one-dimensional confinement
is also discussed.",0601269v1
2007-08-15,Incompatibility of modulated checkerboard patterns with the neutron scattering resonance peak in cuprate superconductors,"Checkerboard patterns have been proposed in order to explain STM experiments
on the cuprates BSCCO and Na-CCOC. However the presence of these patterns has
not been confirmed by a bulk probe such as neutron scattering. In particular,
simple checkerboard patterns are inconsistent with neutron scattering data, in
that they have low energy incommsensurate (IC) spin peaks rotated 45 degrees
from the direction of the charge IC peaks. However, it is unclear whether other
checkerboard patterns can solve the problem. In this paper, we have studied
more complicated checkerboard patterns (""modulated checkerboards"") by using
spin wave theory and analyzed noncollinear checkerboards as well. We find that
the high energy response of the modulated checkerboards is inconsistent with
neutron scattering results, since they fail to exhibit a resonance peak at
(pi,pi), which has recently been shown to be a universal feature of cuprate
superconductors. We further argue that the newly proposed noncollinear
checkerboard also lacks a resonance peak. We thus conclude that to date no
checkerboard pattern has been proposed which satisfies both the low energy
constraints and the high energy constraints imposed by the current body of
experimental data in cuprate superconductors.",0708.1966v3
2010-05-05,Exact solution for quantum dynamics of a periodically-driven two-level-system,"We present a family of exact analytic solutions for non-linear quantum
dynamics of a two-level system (TLS) subject to a periodic-in-time external
field. In constructing the exactly solvable models, we use a ""reverse
engineering"" approach where the form of external perturbation is chosen to
preserve an integrability constraint, which yields a single non-linear
differential equation for the ac-field. A solution to this equation is
expressed in terms of Jacobi elliptic functions with three independent
parameters that allows one to choose the frequency, average value, and
amplitude of the time-dependent field at will. This form of the ac-drive is
especially relevant to the problem of dynamics of TLS charge defects that cause
dielectric losses in superconducting qubits. We apply our exact results to
analyze non-linear dielectric response of such TLSs and show that the position
of the resonance peak in the spectrum of the relevant correlation function is
determined by the quantum-mechanical phase accumulated by the TLS wave-function
over a time evolution cycle. It is shown that in the non-linear regime, this
resonance frequency may be shifted strongly from the value predicted by the
canonical TLS model. We also analyze the ""spin"" survival probability in the
regime of strong external drive and recover a coherent destruction of tunneling
phenomenon within our family of exact solutions, which manifests itself as a
strong suppression of ""spin-flip"" processes and suggests that such non-linear
dynamics in LC-resonators may lead to lower losses.",1005.0652v1
2013-07-17,"Thermalized Non-Equilibrated Matter against Random Matrix Theory, Quantum Chaos and Direct Interaction: Warming up","The idea of a thermalized non-equilibrated state of matter offers a
conceptually new understanding of the strong angular asymmetry. In this compact
review we present some clarifications, corrections and further developments of
the approach, and provide a brief account of results previously discussed but
not reported in the literature. The cross symmetry compound nucleus $S$-matrix
correlations are obtained (i) starting from the unitary $S$-matrix
representation, (ii) by explicitly taking into account a process of energy
equilibration, and (iii) without taking the thermodynamic limit of an infinite
number of particles in the thermalized system. It is conjectured that the long
phase memory is due to the exponentially small total spin off-diagonal
resonance intensity correlations. This manifestly implies that the strong
angular asymmetry intimately relates to extremely small deviations of the
eigenfunction distribution from Gaussian law. The spin diagonal resonance
intensity correlations determine a new time/energy scale for a validity of
random matrix theory. Its definition does not involve overlaps of the many-body
interacting configurations with shell model non-interacting states and thus is
conceptually different from the physical meaning (inverse energy relaxation
time) of the spreading widths introduced by Wigner. Exact Gaussian distribution
of the resonance wave functions corresponds to the instantaneous phase
relaxation. We invite the nuclear reaction community for the competition to
describe, as the first challenge, the strong forward peaking in the typically
evaporation part of the proton spectra. This is necessary to initiate revealing
long-term misconduct in the heavily cross-disciplinary field, also important
for nuclear industry applications.",1307.4490v1
2018-04-09,Probing Ultralight Bosons with Binary Black Holes,"We study the gravitational-wave (GW) signatures of clouds of ultralight
bosons around black holes (BHs) in binary inspirals. These clouds, which are
formed via superradiance instabilities for rapidly rotating BHs, produce
distinct effects in the population of BH masses and spins, and a continuous
monochromatic GW signal. We show that the presence of a binary companion
greatly enriches the dynamical evolution of the system, most remarkably through
the existence of resonant transitions between the growing and decaying modes of
the cloud (analogous to Rabi oscillations in atomic physics). These resonances
have rich phenomenological implications for current and future GW detectors.
Notably, the amplitude of the GW signal from the clouds may be reduced, and in
many cases terminated, much before the binary merger. The presence of a boson
cloud can also be revealed in the GW signal from the binary through the imprint
of finite-size effects, such as spin-induced multipole moments and tidal Love
numbers. The time dependence of the cloud's energy density during the resonance
leads to a sharp feature, or at least attenuation, in the contribution from the
finite-size terms to the waveforms. The observation of these effects would
constrain the properties of putative ultralight bosons through precision GW
data, offering new probes of physics beyond the Standard Model.",1804.03208v2
2019-03-28,$Λ_b$ decays into $Λ_c^*\ell\barν_\ell$ and $Λ_c^*π^-$ $[Λ_c^*=Λ_c(2595)$ \& $Λ_c(2625)]$ and heavy quark spin symmetry,"We study the implications for $\Lambda_b \to \Lambda_c^*\ell\bar{\nu}_\ell$
and $\Lambda_b \to \Lambda_c^*\pi^-$ $[\Lambda_c^*=\Lambda_c(2595)$ and
$\Lambda_c(2625)]$ decays that can be deduced from heavy quark spin symmetry
(HQSS). Identifying the odd parity $\Lambda_c(2595)$ and $\Lambda_c(2625)$
resonances as HQSS partners, with total angular momentum--parity $j_q^P=1^-$
for the light degrees of freedom, we find that the ratios
$\Gamma(\Lambda_b\rightarrow\Lambda_c(2595)\pi^-)/\Gamma(\Lambda_b\rightarrow\Lambda_c(2625)\pi^-)$
and $\Gamma(\Lambda_b\rightarrow \Lambda_c(2595) \ell \bar{\nu}_\ell)/
\Gamma(\Lambda_b\rightarrow\Lambda_c(2625) \ell \bar{\nu}_\ell)$ agree, within
errors, with the experimental values given in the Review of Particle Physics.
We discuss how future, and more precise, measurements of the above branching
fractions could be used to shed light into the inner HQSS structure of the
narrow $\Lambda_c(2595)$ odd-parity resonance. Namely, we show that such
studies would constrain the existence of a sizable $j^P_q=0^-$ component in its
wave-function, and/or of a two-pole pattern, in analogy to the case of the
similar $\Lambda(1405)$ resonance in the strange sector, as suggested by most
of the approaches that describe the $\Lambda_c(2595)$ as a hadron molecule. We
also investigate the lepton flavor universality ratios $R[\Lambda_c^*] = {\cal
B}(\Lambda_b \to \Lambda_c^* \tau\,\bar\nu_\tau)/{\cal B}(\Lambda_b \to
\Lambda_c^* \mu\,\bar\nu_\mu)$, and discuss how $R[\Lambda_c(2595)]$ may be
affected by a new source of potentially large systematic errors if there are
two $\Lambda_c(2595)$ poles.",1903.11911v2
2023-02-15,Coupling of ferromagnetic and antiferromagnetic spin dynamics in Mn$_{2}$Au/NiFe thin-film bilayers,"We investigate magnetization dynamics of Mn$_{2}$Au/Py (Ni$_{80}$Fe$_{20}$)
thin film bilayers using broadband ferromagnetic resonance (FMR) and Brillouin
light scattering spectroscopy. Our bilayers exhibit two resonant modes with
zero-field frequencies up to almost 40 GHz, far above the single-layer Py FMR.
Our model calculations attribute these modes to the coupling of the Py FMR and
the two antiferromagnetic resonance (AFMR) modes of Mn2Au. The
coupling-strength is in the order of 1.6 T$\cdot$nm at room temperature for
nm-thick Py. Our model reveals the dependence of the hybrid modes on the AFMR
frequencies and interfacial coupling as well as the evanescent character of the
spin waves that extend across the Mn$_{2}$Au/Py interface",2302.07915v1
2024-01-22,Versatile quadrature antenna for precise control of large electron spin ensembles in diamond,"We present an easily reproducible inexpensive microwave antenna that can
generate a strong and homogeneous magnetic field of arbitrary polarization,
which enables fast and coherent control of electron spins over a large volume.
Unlike preceding works, we present a resonant antenna that maintains its
resonant behaviour regardless of the proximity of other experimental hardware
components. This robustness is crucial as it enables, amongst others, using
microscope objectives with short working distances to perform wide field
imaging/sensing with bulk diamonds. The antenna generates a magnetic field
strength of 22.3 A/m for 1 W total driving power, which doubles the power
efficiency compared with previously reported patch antenna designs. The
magnetic field homogeneity in a volume of $0.3 \text{mm}^3$, $0.5 \text{mm}^3$
and $1 \text{mm}^3$ is within 6\%, 8\% and 13\%, respectively. The antenna has
a full width at half maximum bandwidth of $\sim$160 MHz and its resonant
frequency can be tuned over a 400 MHz range via four capacitors or varactors.
The antenna has been tested and found to remain within safe handling
temperatures during continuous-wave operation at 8 W. The files required to
reproduce this antenna, which can be built on a standard and affordable double
sided PCB, are provided open-source. This work facilitates a robust and
versatile piece of instrumentation, being particularly appealing for
applications such as high sensitivity magnetometry and wide field
imaging/sensing with Nitrogen Vacancy centers.",2401.11986v2
2009-05-04,Collective dynamics of interacting Ising spins: Exact results for the Bethe lattice,"We study the low temperature dynamics in films made of molecular magnets, i.
e. crystals composed of molecules having large electronic spin S in their
ground state. The electronic spin dynamics is mediated by coupling to a nuclear
spin bath; this coupling allows transitions for a small fraction of electronic
spins between their two energy minima, Sz=+- S, under resonant conditions when
the change of the Zeeman energy in magnetic dipolar field of other electronic
spins is compensated by interaction with nuclear spins. Transitions of resonant
spins can result in opening or closing resonances in their neighbors leading to
the collective dynamics at sufficiently large density P0 of resonant spins. We
formulate and solve the equivalent dynamic percolation problem for the Bethe
lattice (BL) of spins interacting with z neighbors and find that depending on
the density of resonant spins P0 and the number of neighbors z the system has
either one (2<z<6) or two (z > 5) kinetic transitions at P_{0}=Pc1 ~
exp(-1/3)/(3z) and P0=Pc2 ~ exp(-1)/z. The former transition is continuous and
associated with the formation of an infinite cluster of coupled resonant spins
similarly to the static percolation transition occurring at P0 ~ 1/z. The
latter transition, z>5, is discontinuous and associated with the instantaneous
increase in the density of resonant spins from the small value ~ 1/z to near
unity. Experimental implications of our results are discussed.",0905.0482v1
2022-02-23,Secular Spin-orbit Resonances of Black Hole Binaries in AGN Disks,"The spin-orbit misalignment of stellar-mass black hole (sBH) binaries provide
important constraints on the formation channels of merging sBHs. Here, we study
the role of secular spin-orbit resonance in the evolution of a sBH binary
component around a supermassive BH (SMBH) in an AGN disk. We consider the sBH's
spin-precession due to the $J_2$ moment introduced by a circum-sBH disk within
the warping/breaking radius of the disk. We find that the sBH's spin-orbit
misalignment (obliquity) can be excited via spin-orbit resonance between the
sBH binary's orbital nodal precession and the sBH spin-precession driven by a
massive circum-sBH disk. Using an $\alpha$-disk model with
Bondi-Hoyle-Lyttleton accretion, the resonances typically occur for sBH
binaries with semi-major axis of $1$AU, and at a distance of $\sim 1000$AU
around a $10^7$\msun SMBH. The spin-orbit resonances can lead to high sBH
obliquities, and a broad distribution of sBH binary spin-spin misalignments.
However, we note that the Bondi-Hoyle-Lyttleton accretion is much higher than
that of Eddington accretion, which typically results in spin precession being
too low to trigger spin-orbit resonances. Thus, the secular spin-orbit
resonances can be quite rare for sBHs in AGN disks.",2202.11739v2
2021-04-28,The Lowest Broad Alpha Cluster Resonances in $^{19}$F,"There is a deep astrophysical interest in the structure of $^{19}$F states
close to the alpha decay threshold. The nuclear structure of these states is
important for understanding of the development of $\alpha$ clustering in the
$^{20}$Ne region. Emergence of clustered states and generally states that favor
coupling to reaction channels near the corresponding decay thresholds is
currently of special interest in theoretical physics. Excitation function for
$^{15}$N($\alpha$,$\alpha$) elastic scattering was measured by the TTIK method.
These new data together with old, high energy resolution data, were analyzed
using the R matrix approach. $^{19}$F nuclear structure was calculated using
configuration interaction methods with the recently developed effective
interaction Hamiltonian. The parameters of broad low spin $\ell = 0$ and 1
relative partial wave resonances close to the $\alpha$ decay threshold in
$^{19}$F were identified. Detailed theoretical analysis was carried out
identifying all states coupled to the $\ell = 0$ and 1 alpha cluster channels.
Considering hierarchy of states with different harmonic oscillator shell
excitations allows to evaluate coupling to the alpha channels with different
number of nodes in the relative wave function and helps to explain the
distribution of the clustering strength and emergence of broad clustering
resonances. Comparison of clustering in $^{20}$Ne into $^{16}$O+$\alpha$ and
consideration of spin-orbit splitting of the $^{15}$N+$\alpha$ channel provides
additional evidence. Detailed analysis of new and old experimental data allows
to identify a series of $\alpha$ clustering resonances in $^{19}$F and to
assess the distribution of the clustering strength which is of importance to
questions of astrophysics and for theoretical understanding of many-body
physics and emergence of clustering in loosely bound or unstable nuclei.",2104.13987v1
2020-05-20,Controlling the propagation of dipole-exchange spin waves using local inhomogeneity of the anisotropy,"Spin waves are promising candidates to carry, transport, and process
information. Controlling the propagation characteristics of spin waves in
magnetic materials is an essential ingredient for designing spin-wave based
computing architectures. Here, we study the influence of surface
inhomogeneities on the spin-wave signals transmitted through thin films. We use
micromagnetic simulations to study the spin-wave dynamics in an in-plane
magnetized yttrium iron garnet thin film with a thickness in the nanometre
range in the presence of surface defects in the form of locally introduced
uniaxial anisotropies. These defects are used to demonstrate that the Backward
Volume Magnetostatic Spin Waves (BVMSW) are more responsive to backscattering
in comparison to Magnetostatic Surface Spin Waves (MSSWs). For this particular
defect type, the reason for this behavior can be quantitatively related to the
difference in the magnon band structures for the two types of spin waves. To
demonstrate this, we develop a quasi-analytical theory for the scattering
process. It shows an excellent agreement with the micromagnetic simulations,
sheds light on the backscattering processes and provides a new way to analyze
the spin-wave transmission rates in the presence of surface inhomogeneities in
sufficiently thin films, for which the role of exchange energy in the spin-wave
dynamics is significant. Our study paves the way to designing magnonic logic
devices for data processing which rely on a designed control of the spin-wave
transmission.",2005.09965v2
2023-06-16,Theory of propagating spin wave spectroscopy using inductive antennas: conditions for unidirectional energy flow,"Many recent papers report on the interest of spin waves for applications.
This paper revisits the propagating spin wave spectroscopy when using inductive
transceivers connected to a network analyzer. The spin wave conduit can be made
of a non-reciprocal material. The formalism offers a method to understand,
design and optimize devices harnessing propagating spin waves, including when a
unidirectional energy flow is desired. The concept of the mismatch of helicity
between the spin wave and the magnetic field radiated by antennas is first
clarified. Owing to the form of the susceptibility tensor reflecting the
precession ellipticity, there exists specific orientations of the wavevector
for which a perfect helicity mismatch is reached. The spin waves with this
orientation and this direction of wavevector are ""dark"" in the sense that they
do not couple with the inductive antenna. This leads to single-sided wavevector
generation, that should not to be confused with a unidirectional emission of
energy. A method to calculate the antenna-to-antenna transmission parameter is
then provided. Analytical approximations are then applied on situations that
illustrate the respective role of the direction of the spin wave wavevector
versus that of the group velocity. The often-encountered cases of spin waves
possessing either a V-shaped or a flat dispersion relation are revisited. These
reciprocal dispersion relations lead to amplitude non-reciprocity because of
the helicity mismatch phenomenon. Conversely, for spin waves with a line-shaped
dispersion relation, a quasi-unidirectional emission of spin waves occurs. This
situation can be obtained when using the acoustical spin waves of synthetic
antiferromagnets when the wavevector is close to parallel to the applied field.
We finally show that this configuration can be harnessed to design
reconfigurable frequency filters.",2306.09716v2
2019-12-02,Locally resonant metasurfaces for shear waves in granular media,"In this article the physics of horizontally polarized shear waves travelling
across a locally resonant metasurface in an unconsolidated granular medium is
experimentally and numerically explored. The metasurface is comprised of an
arrangement of sub-wavelength horizontal mechanical resonators embedded in
silica microbeads. The metasurface supports a frequency-tailorable attenuation
zone induced by the translational mode of the resonators. The experimental and
numerical findings reveal that the metasurface not only backscatters part of
the energy, but also redirects the wavefront underneath the resonators leading
to a considerable amplitude attenuation at the surface level, when all the
resonators have similar resonant frequency. A more complex picture emerges when
using resonators arranged in a so-called graded design, e.g., with a resonant
frequency increasing/decreasing throughout the metasurface. Unlike Love waves
propagating in a bi-layer medium, shear waves localized at the surface of our
metasurface are not converted into bulk waves. Although a detachment from the
surface occurs, the depth-dependent velocity profile of the granular medium
prevents the mode-conversion, steering again the horizontally polarized shear
waves towards the surface. The outcomes of our experimental and numerical
studies allow for understanding the dynamics of wave propagation in resonant
metamaterials embedded in vertically inhomogeneous soils and, therefore, are
essential for improving the design of engineered devices for ground vibration
and seismic wave containment.",1912.00617v1
2007-09-05,Electron spin manipulation and resonator readout in a double quantum dot nano-electromechanical system,"Magnetically coupling a nano-mechanical resonator to a double quantum dot
confining two electrons can enable the manipulation of a single electron spin
and the readout of the resonator's natural frequency. When the Larmor frequency
matches the resonator frequency, the electron spin in one of the dots can be
selectively flipped by the magnetised resonator. By simultaneously measuring
the charge state of the two-electron double quantum dots, this transition can
be detected thus enabling the natural frequency of the mechanical resonator to
be determined.",0709.0593v2
2018-02-13,"Platonic crystal with low-frequency locally resonant snail structures. Wave trapping, transmission amplification and shielding","We propose a new type of platonic crystal. The proposed microstructured plate
includes snail resonators with low-frequency resonant vibrations. The
particular dynamic effect of the resonators are highlighted by a comparative
analysis of dispersion properties of homo- geneous and perforated plates.
Analytical and numerical estimates of classes of standing waves are given and
the analysis on a macrocell shows the possibility to obtain localization, wave
trapping and edge waves. Applications include transmission amplification within
two plates separated by a small ligament. Finally we proposed a design
procedure to suppress low frequency flexural vibration in an elongated plate
implementing a by-pass system re- routing waves within the mechanical system.",1802.08316v1
2015-08-31,Dissipation and resonance frequency shift of a resonator magnetically coupled to a semiclassical spin,"We calculate the change of the properties of a resonator, when coupled to a
semiclassical spin by means of the magnetic field. Starting with the Lagrangian
of the complete system, we provide an analytical expression for the linear
response function for the motion of the resonator, thereby considering the
influence of the resonator on the spin and vice versa. This analysis shows that
the resonance frequency and effective dissipation factor can change
significantly due to the relaxation times of the spin. We first derive this for
a system consisting of a spin and mechanical resonator and thereafter apply the
same calculations to an electromagnetic resonator. Moreover, the applicability
of the method is generalized to a resonator coupled to general two and more
level systems, providing a key to understand some of the problems of two level
systems in quantum devices.",1508.07972v2
2000-11-03,Dirac quasiparticles in the mixed state,"Energies and wave functions are calculated for d-wave quasiparticles in the
mixed state using the formalism of Franz and Tesanovic for the low-lying energy
levels. The accuracy of the plane-wave expansion is explored by comparing
approximate to exact results for a simplified one-dimensional problem, and the
convergence of the plane- wave expansion to the two-dimensional case is
studied. The results are used to calculate the low-energy tunneling density of
states and the low-temperature specific heat, and these theoretical results are
compared to semiclassical treatments and to the available data. Implications
for the muon spin resonance measurements of vortex core size are also
discussed.",0011053v2
1994-03-21,l=0 to l=1 Transition Form Factors,"A method is proposed to extend the hard scattering picture of Brodsky and
Lepage to transitions between hadrons with orbital angular momentum l=0 and
l=1. The use of covariant spin wave functions turns out to be very helpful in
formulating that method. As a first application we construct a light-cone wave
function of the nucleon resonance $N^*(1535)$ in the quark-diquark picture.
Using this wave function and the extended hard scattering picture, the
$N$--$N^*$ transition form factors are calculated at large momentum transfer
and the results compared to experimental data. As a further application of our
method we briefly discuss the $\pi$--$a_1$ form factors in an appendix.",9403319v2
2008-10-07,Corotational Damping of Diskoseismic C-modes in Black Hole Accretion Discs,"Diskoseismic c-modes in accretion discs have been invoked to explain
low-frequency variabilities observed in black-hole X-ray binaries. These modes
are trapped in the inner-most region of the disc and have frequencies much
lower than the rotation frequency at the disc inner radius. We show that
because the trapped waves can tunnel through the evanescent barrier to the
corotational wave zone, the c-modes are damped due to wave absorption at the
corotation resonance. We calculate the corotational damping rates of various
c-modes using the WKB approximation. The damping rate varies widely depending
on the mode frequency, the black hole spin parameter and the disc sound speed,
and is generally much less than 10% of the mode frequency. A sufficiently
strong excitation mechanism is needed to overcome this corotational damping and
make the mode observable.",0810.1299v3
2010-01-28,Stability of a Fully Magnetized Ferromagnetic state in Repulsively Interacting Ultracold Fermi Gases,"We construct a variational wave function to study whether a fully polarized
Fermi sea is energetically stable against a single spin flip. Our variational
wave function contains sufficient short-range correlation at least to the same
level as Gutzwiller's projected wave function. For Hubbard lattice model and
continuum model with pure repulsive interaction, we show a fully polarized
Fermi sea is generally unstable even when the repulsive strength becomes
infinite. While for a resonance model, ferromagnetic state is possible if the
s-wave scattering length is positive and sufficiently large, and the system is
prepared in scattering state orthogonal to molecular bound state. However, we
can not rule out the possibility that more exotic correlation can destabilize
the ferromagnetic state.",1001.5139v2
2014-03-06,Partial Wave Analysis at BESIII,"The BESIII experiment in Beijing takes data in $\tau$-charm domain since
2009. For the moment the world largest samples of $J/\psi$, $\psi(3686)$,
$\psi(3770)$ and $\psi(4040)$ data have been collected. Hadron spectroscopy is
a unique way to access QCD, which is one of the most important physics goals of
BESIII. Experimental search of new forms of hadrons and subsequent
investigation of their properties would provide validation of and valuable
input to the quantitative understanding of QCD. The key to success lies in high
levels of precision during the measurement and high statistics in the recorded
data set complemented with sophisticated analysis methods. Partial wave
analysis (PWA) is a powerful tool to study the hadron spectroscopy, that allows
one to extract the resonance's spin-parity, mass, width and decay properties
with high sensitivity and accuracy. In this poster, we present the working PWA
framework of BESIII -- GPUPWA and the recent results of PWA of
$J/\psi\to\gamma\eta\eta$. GPUPWA is a PWA framework for high statistics
partial wave analyses harnessing the GPU parallel computing.",1403.1337v1
2014-04-04,Giant Goos-Hänchen shift in Scattering: the role of interfering Localized Plasmon modes,"The longitudinal and the transverse beam shifts, namely, the Goos-H\""anchen
(GH) and the Spin-Hall (SH) shifts are usually observed at planar interfaces.
It has recently been shown that the transverse SH shift may also arise due to
scattering of plane waves. Here, we show that analogous in-plane (longitudinal)
shift also exist in scattering of plane waves from micro/nano systems. We study
both the GH and the SH shifts in plasmonic metal nanoparticles/ nanostructures
and dielectric micro-particles employing a unified framework that utilizes the
transverse components of the Poynting vector of the scattered wave. The results
demonstrate that interference of neighboring resonance modes in plasmonic
nanostructures (e.g., electric dipolar and quadrupolar modes in metal spheres)
leads to giant enhancement of GH shift in scattering from such systems. We also
unravel interesting correlations between these shifts with the polarimetry
parameters, diattenuation and retardance.",1404.1166v1
2018-08-24,Pulse analysis by delayed absorption from a coherently excited atom,"In this tutorial we provide a short review of attosecond pulse
characterization techniques and a pedagogical account of a recently proposed
method called Pulse Analysis by Delayed Absorption (PANDA) [Pabst and
Dahlstr\""om, Phys. Rev. A, 94, 13411 (2016)]. We discuss possible
implementations of PANDA in alkali atoms using either principal quantum number
wave packets or spin-orbit wave packets. The main merit of the PANDA method is
that it can be used as a pulse characterization method that is free from atomic
latency effects, such as scattering phase shifts and long-lived atomic
resonances. Finally, we propose that combining the PANDA method with
angle-resolved photoelectron detection should allow for experimental
measurements of attosecond delays in photoionization from bound wave packets on
the order of tens of attoseconds.",1808.08102v2
2021-01-03,Two-dimensional superconducting fluctuations associated with charge density wave stripes in La$_{1.87}$Sr$_{0.13}$Cu$_{0.99}$Fe$_{0.01}$O$_4$,"The presence of a small concentration of in-plane Fe dopants in
La$_{1.87}$Sr$_{0.13}$Cu$_{0.99}$Fe$_{0.01}$O$_4$ is known to enhance
stripe-like spin and charge density wave (SDW and CDW) order, and suppress the
superconducting $T_c$. Here, we show that it also induces highly
two-dimensional (2D) superconducting correlations that have been argued to be
signatures of a new form of superconducting order, so-called pair-density-wave
(PDW) order. In addition, using the resonant soft x-ray scattering, we find
that the 2D superconducting fluctuation is strongly associated with the CDW
stripe. In particular, the PDW signature first appears when the correlation
length of the CDW stripe grows over eight times the lattice unit ($\sim$ 8$a$).
These results provide critical conditions for the formation of PDW order.",2101.00539v1
2023-03-15,Acoustically driven magnon-phonon coupling in a layered antiferromagnet,"Harnessing the causal relationships between mechanical and magnetic
properties of van der Waals materials presents a wealth of untapped opportunity
for scientific and technological advancement, from precision sensing to novel
memories. This can, however, only be exploited if the means exist to
efficiently interface with the magnetoelastic interaction. Here, we demonstrate
acoustically-driven spin-wave resonance in a crystalline antiferromagnet,
chromium trichloride, via surface acoustic wave irradiation. The resulting
magnon-phonon coupling is found to depend strongly on sample temperature and
external magnetic field orientation, and displays a high sensitivity to
extremely weak magnetic anisotropy fields in the few~mT range. Our work
demonstrates a natural pairing between power-efficient strain-wave technology
and the excellent mechanical properties of van der Waals materials,
representing a foothold towards widespread future adoption of dynamic
magneto-acoustics.",2303.08305v1
2023-09-22,Strongly Coupled Spin Waves and Surface Acoustic Waves at Room Temperature,"Here, we report the observation of strong coupling between magnons and
surface acoustic wave (SAW) phonons in a thin CoFeB film constructed in an
on-chip SAW resonator by analyzing SAW phonon dispersion anticrossings. Our
device design provides the tunability of the film thickness with a fixed phonon
wavelength, which is a departure from the conventional approach in strong
magnon--phonon coupling research. We detect a monotonic increase in the
coupling strength by expanding the film thickness, which agrees with our
theoretical model. Our work offers a significant way to advance fundamental
research and the development of devices based on magnon--phonon hybrid
quasiparticles.",2309.12690v1
2012-02-03,Magnetic resonance in the ordered phases of the 2D frustrated quantum magnet Cs2CuCl4,"The temperature evolution of the electron spin resonance is studied at
cooling the crystal samples of Cs2CuCl4 through the Neel point 0.62 K. A
coexistence of the high-frequency spinon type resonance developed in the
spin-liquid phase and of the low-frequency antiferromagnetic resonance was
found in the ordered phase. The low-frequency magnetic resonance spectrum in
the low field range has two gapped branches and corresponds well to the
spectrum of spin excitations of a planar spiral spin structure with two axes of
the anisotropy. The field induced phase transitions result in a more
complicated low-frequency spectra.",1202.0783v1
2013-06-10,Spin Transfer of Quantum Information between Majorana Modes and a Resonator,"We show that resonant coupling and entanglement between a mechanical
resonator and majorana bound states can be achieved via spin currents in a 1D
quantum wire with strong spin-orbit interactions. The bound states induced by
vibrating and stationary magnets can hybridize thus resulting in spin-current
induced $4\pi$-periodic torque, as a function of the relative field angle,
acting on the resonator. We study the feasibility of detecting and manipulating
majorana bound states with the use of magnetic resonance force microscopy
techniques.",1306.2339v1
2018-10-08,On the optical nonreciprocity and slow light propagation in coupled spinning optomechanical resonators,"We study the optical transmission characteristics of pump-probe driven
spinning optomechanical ring resonators coupled in a series configuration.
After performing the steady-state analysis valid for an arbitrary number of
resonators, as an example, we discuss the two-resonator problem in detail.
Therein, we focus on how changing the optical Sagnac effect due to same or
opposite spinning directions of resonators can lead to enhanced, non-reciprocal
and delayed probe light transmission. This work can help in devising spin
degree of freedom based novel devices of manipulating light propagation in
quantum networks and quantum communication technologies.",1810.03709v1
2010-08-27,Enhancement of the spin pumping efficiency by spin-wave mode selection,"The spin pumping efficiency of lateral standing spin wave modes in a
rectangular YIG/Pt sample has been investigated by means of the inverse
spin-Hall effect (ISHE). The standing spin waves drive spin pumping, the
generation of spin currents from magnetization precession, into the Pt layer
which is converted into a detectable voltage due to the ISHE. We discovered
that the spin pumping efficiency is significantly higher for lateral standing
surface spin waves rather than for volume spin wave modes. The results suggest
that the use of higher-mode surface spin waves allows for the fabrication of an
efficient spin-current injector.",1008.4714v2
2015-03-25,Theory of Optical Leaky-Wave Antenna Integrated in a Ring Resonator for Radiation Control,"The integration of a leaky-wave antenna with a ring resonator is presented
using analytical guided wave models. The device consists of a ring resonator
fed by a directional coupler, where the ring resonator path includes a
leaky-wave antenna segment. The resonator integration provides two main
advantages: the high-quality factor ensures effective control of radiation
intensity by controlling the resonance conditions and the efficient radiation
from a leaky-wave antenna even when its length is much smaller than the
propagation length of the leaky wave. We devise an analytical model of the
guided wave propagation along a directional coupler and the ring resonator path
including the antenna and non-radiating segments. The trade-offs regarding the
quality factor of resonance and the antenna efficiency of such a design is
reported in terms of the coupler parameters, leaky-wave constant and radiation
length. Finally a CMOS-compatible OLWA design suitable for the ring resonator
integration is designed where Silicon is utilized as the waveguide material for
a possible electronic control of radiation intensity. The simulation results
together with the analytical model show that slight variations in the
leaky-wave's propagation constant, realized through excitation of excess
carriers in Si domain, is sufficient to control the far-field radiation
modulation with high extinction ratio.",1503.07515v1
2019-10-17,Spontaneous superharmonic internal wave generation by modal interactions in uniform and nonuniform stratifications,"Triadic resonance is one mechanism via which internal waves dissipate their
energy, often at locations away from their generation sites. In this paper, we
perform a combined theoretical and numerical study of triadic resonance in
internal wave modes in a finite-depth ocean with background rotation and an
arbitrary stratification profile. The spatial evolution of the modal amplitudes
within a resonant triad are first derived based on the requirement that the
nonlinear solution at leading order cannot diverge. The amplitude evolution
equations are then numerically solved for two different cases: (i) modes 1 and
2 at a specific frequency ({\omega_0}) in triadic resonance with the mode-1
superharmonic wave (2{\omega_0}) in a uniform stratification, and (ii) a
self-interacting mode-3 at a specific frequency {\omega_0} in triadic resonance
with the mode-2 (2{\omega_0}) in a nonuniform stratification representative of
the ocean. Quantitative estimates of energy transfer rates within the resonant
triad show that superharmonic wave generation resulting from modal interactions
should be an important consideration alongside other triadic resonances like
parametric subharmonic instability (PSI). Remarkably, in case (ii), the
amplitude evolution equations suggest that any initial energy in mode-3 at
{\omega_0} would get permanently transferred to mode-2 at frequency
2{\omega_0}. Direct numerical simulations (DNS) are then performed to show the
spontaneous generation of superharmonic internal waves resulting from modal
interactions in the aforementioned two cases, and quantitatively validate the
initial spatial evolution of the wave field predicted by the amplitude
evolution equations. DNS at off-resonant frequencies are used to identify the
range of primary wave frequencies (around the resonant frequency) over which
spontaneous superharmonic wave generation occurs.",1910.07777v1
2012-11-11,Resonances for activity waves in spherical mean field dynamos,"We study activity waves of the kind that determine cyclic magnetic activity
of various stars, including the Sun, as a more general physical rather than a
purely astronomical problem. We try to identify resonances which are expected
to occur when a mean-field dynamo excites waves of quasi-stationary magnetic
field in two distinct spherical layers. We isolate some features that can be
associated with resonances in the profiles of energy or frequency plotted
versus a dynamo governing parameter. Rather unexpectedly however the resonances
in spherical dynamos take a much less spectacular form than resonances in many
more familiar branches of physics. In particular, we find that the magnitudes
of resonant phenomena are much smaller than seem detectable by astronomical
observations, and plausibly any related effects in laboratory dynamo
experiments (which of course are not in gravitating spheres!) are also small.
We discuss specific features relevant to resonant phenomena in spherical
dynamos, and find parametric resonance to be the most pronounced type of
resonance phenomena. Resonance conditions for these dynamo wave resonances are
rather different from those for more conventional branches of physics. We
suggest that the relative insignificance of the phenomenon in this case is
because the phenomena of excitation and propagation of the activity waves are
not well-separated from each other and this, together with the nonlinear nature
of more-or-less realistic dynamos, suppress the resonances and makes them much
less pronounced than resonant effects, for example in optics.",1211.2414v1
2019-02-15,Long-distance entangling gates between quantum dot spins mediated by a superconducting resonator,"Recent experiments with silicon qubits demonstrated strong coupling of a
microwave resonator to the spin of a single electron in a double quantum dot,
opening up the possibility of long-range spin-spin interactions. We present our
theoretical calculation of effective interactions between distant quantum dot
spins coupled by a resonator, and propose a protocol for fast, high-fidelity
two-qubit gates consistent with experimentally demonstrated capabilities. Our
simulations show that, in the presence of noise, spin-spin entangling gates
significantly outperform cavity-mediated gates on charge qubits.",1902.05704v2
2017-07-11,Tilting Styx and Nix but not Uranus with a Spin-Precession-Mean-motion resonance,"A Hamiltonian model is constructed for the spin axis of a planet perturbed by
a nearby planet with both planets in orbit about star. We expand the
planet-planet gravitational potential perturbation to first order in orbital
inclinations and eccentricities, finding terms describing spin resonances
involving the spin precession rate and the two planetary mean motions.
Convergent planetary migration allows the spinning planet to be captured into
spin resonance. With initial obliquity near zero, the spin resonance can lift
the planet's obliquity to near 90 or 180 degrees depending upon whether the
spin resonance is first or zero-th order in inclination. Past capture of Uranus
into such a spin resonance could give an alternative non-collisional scenario
accounting for Uranus's high obliquity. However we find that the time spent in
spin resonance must be so long that this scenario cannot be responsible for
Uranus's high obliquity. Our model can be used to study spin resonance in
satellite systems. Our Hamiltonian model explains how Styx and Nix can be
tilted to high obliquity via outward migration of Charon, a phenomenon
previously seen in numerical simulations.",1707.03180v2
2022-09-20,Dispersive cavity-mediated quantum gate between driven dot-donor nuclear spins,"Nuclear spins show exceptionally long coherence times but the underlying good
isolation from their environment is a challenge when it comes to controlling
nuclear spin qubits. A particular difficulty, not only for nuclear spin qubits,
is the realization of two-qubit gates between distant qubits. Recently, strong
coupling between an electron spin and microwave resonator photons as well as a
microwave resonator mediated coupling between two electron spins both in the
resonant and the dispersive regime have been reported and, thus, a microwave
resonator mediated electron spin two qubit gate seems to be in reach. Inspired
by these findings, we theoretically investigate the interaction of a microwave
resonator with a hybrid quantum dot-donor (QDD) system consisting of a gate
defined Si QD and a laterally displaced $^{31}$P phosphorous donor atom
implanted in the Si host material. We find that driving the QDD system allows
to compensate the frequency mismatch between the donor nuclear spin splitting
in the MHz regime and typical superconducting resonator frequencies in the GHz
regime, and also enables an effective nuclear spin-photon coupling. While we
expect this coupling to be weak, we predict that coupling the nuclear spins of
two distant QDD systems dispersively to the microwave resonator allows the
implementation of a resonator mediated nuclear spin two-qubit
$\sqrt{i\mathrm{SWAP}}$ gate with a gate fidelity approaching $90\%$.",2209.10026v2
2011-06-22,All-magnonic spin-transfer torque and domain wall propagation,"The spin wave transportation through a transverse magnetic domain wall (DW)
in a magnetic nanowire is studied. It is found that spin wave passes through a
DW without reflection. A magnon, the quantum of the spin wave, carries opposite
spins on the two sides of the DW. As a result, there is a spin angular momentum
transfer from the propagating magnons to the DW. This magnonic spin-transfer
torque can efficiently drive a DW to propagate in the opposite direction to
that of the spin wave.",1106.4382v2
2013-05-07,Spin Wave Excitation in Magnetic Insulator Thin Films by Spin-Transfer Torque,"We describe excitation of dipole-exchange spin waves in insulating magnetic
thin films by spin current injection at the surface of the film. An easy-axis
magnetic surface anisotropy can induce a non-chiral surface spin wave mode with
penetration depth inversely proportional to the strength of the surface
anisotropy, which strongly reduces the critical current and enhances the
excitation power. The importance of the interface spin wave modes on the
excitation spectrum is reduced by spin pumping, which depends on the quality of
the interface as expressed by the spin mixing conductance.",1305.1364v2
2020-12-15,Spin wave spectral probing of possible microstates in building-block of macroscopically degenerate artificial spin ice,"We have investigated the spin wave modes of strongly dipolar coupled, highly
anisotropic nanoislands forming square artificial spin ice system using
micromagnetic simulation in MUMAX3 in combination with Matlab coding.
Artificial spin ice is considered to be formed by the four square ring-type
structure of elliptical cross-section nanoislands. Our results state the direct
relation between the spin wave modes generated and the micro-states formed in
the system. We have shown that single ring type structure can alone be
adequately used to understand the spin wave modes of square artificial spin
ice.",2012.08093v1
2013-10-26,Resonant waves in elastic structured media: dynamic homogenisation versus Green's functions,"We address an important issue of a dynamic homogenisation in vector
elasticity for a doubly periodic mass-spring elastic lattice. The notion of
logarithmically growing resonant waves is used in a complete analysis of
star-shaped wave forms induced by an oscillating point force. We note that the
dispersion surfaces for Floquet-Bloch waves in an elastic lattice main contain
critical points of the saddle type. Based on the local quadratic approximations
of the frequency, as a function of wave vector components, we deduce properties
of a transient asymptotic solution as the contribution of the point source to
the wave form. In this way, we describe local Green's functions as localized
wave forms corresponding to the resonant frequency. The peculiarity of the
problem lies in the fact that, at the same resonant frequency, the Taylor
quadratic approximations for different groups of the resonant points are
different, and hence we deal with different local Green's functions. Thus,
there is no uniformly defined homogenisation procedure for a given resonant
frequency. Instead, the continuous approximation of the wave field can be
obtained through the asymptotic analysis of the lattice Green's functions.",1310.7089v1
2014-11-19,Global surface wave resonances of the earth magnetosphere and their possible manifestation,"In this paper global surface wave modes supported by plasma discontinuities
at both the magnetopause and the plasmapause are considered. The ionosphere at
the ends of the magnetic field lines of the earth outer magnetosphere is
considered as reflecting boundaries of the surface waves that propagate along
the plasma boundaries. As a result a standing wave structure along the magnetic
field fluxes of the outer magnetosphere, i.e. surface wave resonance structure
can be formed. Due to quantized wavenumbers along the magnetic field lines, the
surface wave resonance possesses quantified frequencies in a following way: f =
nfres, where fres is frequency of the corresponding fundamental surface wave
resonance and n is an integer. Global Pc5 pulsations have been observed and
interpreted mostly as cavity modes of the earth magnetosphere. The global Pc5
pulsations however could alternatively be interpreted as ultra low-frequency
surface wave resonances of the earth magnetosphere that do not necessarily
involve the cavity mode-field aligned resonance transformation concept.",1411.5218v1
2001-02-13,Resonant electron transmission through a finite quantum spin chain,"Electron transport in a finite one dimensional quantum spin chain (with
ferromagnetic exchange) is studied within an $s-d$ exchange Hamiltonian. Spin
transfer coefficients strongly depend on the sign of the $s-d$ exchange
constant. For a ferromagnetic coupling, they exhibit a novel resonant pattern,
reflecting the salient features of the combined electron-spin system. Spin-flip
processes are inelastic and feasible at finite voltage or at finite
temperature.",0102236v1
2016-04-25,Oblique internal-wave chain resonance over seabed corrugations,"We show that monochromatic long-crested corrugations on an otherwise flat
seafloor can coherently scatter the energy of an oblique incident internal wave
to multiple multi-directional higher-mode waves via a series of resonant
interactions. We demonstrate that a resonance between seabed corrugations and a
normally or slightly oblique incident internal wave results in a series of
follow-up resonant interactions, which take place between the same corrugations
and successively resonated shorter waves. A chain resonance of internal waves
that carries energy to small scales is thus obtained, and we find that the
Richardson number decreases by several orders of magnitude over the corrugated
patch. If the incidence angle is large, and the incident wave perfectly
satisfies a resonance condition with the topography, it turns out that not many
higher-mode resonance or near-resonance conditions can be satisfied, such that
energy stays confined within the first few modes. Nevertheless, if the incident
waves are sufficiently detuned from satisfying a perfect resonance condition
with the seabed corrugations, then we show that this frequency detuning may
balance off the large detuning due to oblique incidence, leading to a chain
resonance that again carries energy to small scales. The evolution of the
incident and resonated wave amplitudes is predicted from the envelope equation
for internal waves over resonant seabed topography in a three-dimensional
rotating fluid, which we derive considering the Boussinesq and $f$-plane
approximations with $f$ the Coriolis frequency, linear density stratification
and small-amplitude corrugations. Our results suggest that topographic features
on the ocean floor with a dominant wavenumber vector, through the chain
resonance mechanism elucidated here, may play a more important role than
previously thought in the enhancement of diapycnal mixing and energy
dissipation.",1604.07308v2
2006-01-17,Spin wave instabilities and field induced transitions in heavy fermions,"We study phase transitions in heavy fermion systems due to spin-wave
instabilities. One motivation is to determine the changes in the spin-wave
parameters of a magnetically ordered heavy fermion system as it approaches a
quantum critical point (QCP) by applying pressure. The other more actual is to
provide an alternative approach, based on spin-wave instabilities, for the
magnetic field induced transitions recently observed in antiferromagnetic heavy
fermion materials.",0601385v1
2013-01-23,Characterization of magnetostatic surface spin waves in magnetic thin films: evaluation for microelectronic applications,"The authors have investigated the possibility of utilizing spin waves for
inter- and intra-chip communications, and as logic elements using both
simulations and experimental techniques. Through simulations it has been shown
that the decay lengths of magnetostatic spin waves are affected most by the
damping parameter, and least by the exchange stiffness constant. The damping
and dispersion properties of spin waves limit the attenuation length to several
tens of microns. Thus, we have ruled out the possibility of inter-chip
communications via spin waves. Experimental techniques for the extraction of
the dispersion relationship have also been demonstrated, along with
experimental demonstrations of spin wave interference for amplitude modulation.
The effectiveness of spin wave modulation through interference, along with the
capability of determining the spin wave dispersion relationships electrically
during manufacturing and testing phase of chip production may pave the way for
using spin waves in analog computing wherein the circuitry required for
performing similar functionality becomes prohibitive.",1301.5395v1
2013-09-10,Spin wave excitation patterns generated by spin torque oscillators,"Spin torque nano oscillators (STNO) are nano-scale devices that can convert a
direct current into short wave-length spin-wave excitations in a ferromagnetic
layer. We show that arrays of STNO can be used to create directional spin-wave
radiation similar to electromagnetic antennas. Combining STNO excitations with
planar spin waves also creates interference patterns. We show that these
interference patterns are static and have information on the wavelength and
phase of the spin waves emitted from the STNO.We describe means of actively
controlling spin-wave radiation patterns with the direct current owing through
STNO, which is useful in on-chip communication and information processing and
could be a promising technique for studying short wave-length spin waves in
different materials.",1309.2436v1
2016-10-27,Spin-wave propagation in ultra-thin YIG based waveguides,"Spin-wave propagation in an assembly of microfabricated 20 nm thick, 2.5
{\mu}m wide Yttrium Iron Garnet (YIG) waveguides is studied using propagating
spin-wave spectroscopy (PSWS) and phase resolved micro-focused Brillouin Light
Scattering ({\mu}-BLS) spectroscopy. We show that spin-wave propagation in 50
parallel waveguides is robust against microfabrication induced imperfections.
Spin-wave propagation parameters are studied in a wide range of excitation
frequencies for the Damon-Eshbach (DE) configuration. As expected from its low
damping, YIG allows the propagation of spin waves over long distances (the
attenuation lengths is 25 {\mu}m at \mu$_{0}$H = 45 mT). Direct mapping of spin
waves by {\mu}-BLS allows us to reconstruct the spin-wave dispersion relation
and to confirm the multi-mode propagation in the waveguides, glimpsed by
propagating spin-wave spectroscopy.",1610.08756v1
2019-02-25,Nonreciprocal nano-optics with spin-waves in synthetic antiferromagnets,"Integrated optically-inspired wave-based processing is envisioned to
outperform digital architectures in specific tasks, such as image processing
and speech recognition. In this view, spin-waves represent a promising route
due to their nanoscale wavelength in the GHz frequency range and rich
phenomenology. Here, we realize a versatile optically-inspired platform using
spin-waves, demonstrating the wavefront engineering, focusing, and robust
interference of spin-waves with nanoscale wavelength. In particular, we use
magnonic nanoantennas based on tailored spin-textures for launching spatially
shaped coherent wavefronts, diffraction-limited spin-wave beams, and generating
robust multi-beam interference patterns, which spatially extend for several
times the spin-wave wavelength. Furthermore, we show that intriguing features,
such as resilience to back-reflection, naturally arise from the spin-wave
nonreciprocity in synthetic antiferromagnets, preserving the high quality of
the interference patterns from spurious counterpropagating modes. This work
represents a fundamental step towards the realization of nanoscale
optically-inspired devices based on spin-waves.",1902.09420v2
2016-03-17,Spin-Wave Fiber,"Spin waves are collective excitations propagating in the magnetic medium with
ordered magnetizations. Magnonics, utilizing the spin wave (magnon) as
information carrier, is a promising candidate for low-dissipation computation
and communication technologies. We discover that, due to the
Dzyaloshinskii-Moriya interaction, the scattering behavior of spin wave at a
magnetic domain wall follows a generalized Snell's law, where two magnetic
domains work as two different mediums. Similar to optical total reflection that
occurs at the water-air interfaces, spin waves may experience total reflection
at magnetic domain walls when their incident angle larger than a critical
value. We design a spin wave fiber using a magnetic domain structure with two
domain walls, and demonstrate that such a spin wave fiber can transmit spin
waves over long distance by total internal reflections, in analogy to an
optical fiber. Our design of spin wave fiber opens up new possibilities in pure
magnetic information processing.",1603.05325v1
2020-09-08,Time refraction of spin waves,"We present an experimental study of time refraction of spin waves propagating
in microscopic waveguides under the influence of time-varying magnetic fields.
Using space- and time-resolved Brillouin light scattering microscopy, we
demonstrate that the broken translational symmetry along the time coordinate
can be used to in- or decrease the energy of spin waves during their
propagation. This allows for a broadband and controllable shift of the
spin-wave frequency. Using an integrated design of spin-wave waveguide and
microscopic current line for the generation of strong, nanosecond-long,
magnetic field pulses, a conversion efficiency up to 39% of the carrier
spin-wave frequency is achieved, significantly larger compared to photonic
systems. Given the strength of the magnetic field pulses and its strong impact
on the spin-wave dispersion relation, the effect of time refraction can be
quantified on a length scale comparable to the spin-wave wavelength.
Furthermore, we utilize time refraction to excite spin-wave bursts with pulse
durations in the nanosecond range and a frequency shift depending on the pulse
polarity.",2009.03654v1
2017-01-05,Excitation and detection of short-waved spin waves in ultrathin Ta/CoFeB/MgO-layer system suitable for spin-orbit-torque magnonics,"We report on the excitation and detection of short-waved spin waves with wave
vectors up to about $40\,\mathrm{rad}\,\mu\mathrm{m}^{-1}$ in spin-wave
waveguides made from ultrathin, in-plane magnetized Co$_{8}$Fe$_{72}$B$_{20}$
(CoFeB). The CoFeB is incorporated in a layer stack of Ta/CoFeB/Mgo, a layer
system featuring large spin orbit torques and a large perpendicular magnetic
anisotropy constant. The short-waved spin waves are excited by nanometric
coplanar waveguides and are detected via spin rectification and microfocussed
Brillouin light scattering spectroscopy. We show that the large perpendicular
magnetic anisotropy benefits the spin-wave lifetime greatly, resulting in a
lifetime comparable to bulk systems without interfacial damping. The presented
results pave the way for the successful extension of magnonics to ultrathin
asymmetric layer stacks featuring large spin orbit torques.",1701.01399v1
2020-06-23,An Introduction to Spin Wave Computing,"This paper provides a tutorial overview over recent vigorous efforts to
develop computing systems based on spin waves instead of charges and voltages.
Spin-wave computing can be considered as a subfield of spintronics, which uses
magnetic excitations for computation and memory applications. The tutorial
combines backgrounds in spin-wave and device physics as well as circuit
engineering to create synergies between the physics and electrical engineering
communities to advance the field towards practical spin-wave circuits. After an
introduction to magnetic interactions and spin-wave physics, all relevant basic
aspects of spin-wave computing and individual spin-wave devices are reviewed.
The focus is on spin-wave majority gates as they are the most prominently
pursued device concept. Subsequently, we discuss the current status and the
challenges to combine spin-wave gates and obtain circuits and ultimately
computing systems, considering essential aspects such as gate interconnection,
logic level restoration, input-output consistency, and fan-out achievement. We
argue that spin-wave circuits need to be embedded in conventional CMOS circuits
to obtain complete functional hybrid computing systems. The state of the art of
benchmarking such hybrid spin-wave--CMOS systems is reviewed and the current
challenges to realize such systems are discussed. The benchmark indicates that
hybrid spin-wave--CMOS systems promise ultralow-power operation and may
ultimately outperform conventional CMOS circuits in terms of the
power-delay-area product. Current challenges to achieve this goal include
low-power signal restoration in spin-wave circuits as well as efficient
spin-wave transducers.",2006.12905v3
2021-03-14,Dispersion relation of nutation surface spin waves in ferromagnets,"Inertia effects in magnetization dynamics are theoretically shown to result
in a different type of spin waves, i.e. nutation surface spin waves, which
propagate at terahertz frequencies in in-plane magnetized ferromagnetic thin
films. Considering the magnetostatic limit, i.e. neglecting exchange coupling,
we calculate dispersion relation and group velocity, which we find to be slower
than the velocity of conventional (precession) spin waves. In addition, we find
that the nutation surface spin waves are backward spin waves. Furthermore, we
show that inertia causes a decrease of the frequency of the precession spin
waves, namely magnetostatic surface spin waves and backward volume
magnetostatic spin waves. The magnitude of the decrease depends on the magnetic
properties of the film and its geometry.",2103.07864v2
2023-06-30,Spin Wave Driven Skyrmions in a Bipartite Antiferromagnetic Lattice,"We show that a Skyrmion in a classical bipartite antiferromagnetic lattice
can be spatially displaced in a controlled manner by externally applied spin
waves. We reveal the relation between the Skyrmion motion and the spin wave
properties. To this end, we derive a classical spin wave formalism which is
tailored to the antiferromagnetic two-dimensional square lattice. The
antiferromagnetic spin waves can be classified into two types with respect to
their polarization, with two modes each. The circularly polarized spin waves
oscillate with different amplitudes in the respective sublattices and induce a
Skyrmion Hall effect. The two modes are symmetric under sublattices exchange
and determine the overall sign of the Hall angle. Linearly polarized spin waves
oscillate elliptically, however, with the same amplitude on each sublattice.
These accelerate the Skyrmion solely into their own propagation direction. The
two modes are symmetric under component x-y exchange and impact Bloch- or
N\'eel Skyrmions differently. Our results indicate possible technical
applications of spin-wave driven Skyrmion motion. As one example we propose a
racetrack where spin waves pump Skyrmions along the track in antiferromagnets.",2306.17678v2
2023-08-03,Hybrid Spin and Anomalous Spin-Momentum Locking in Surface Elastic Waves,"Transverse spin of surface waves is a universal phenomenon which has recently
attracted significant attention in optics and acoustics. It appears in gravity
water waves, surface plasmon-polaritons, surface acoustic waves, and exhibits
remarkable intrinsic spin-momentum locking, which has found useful applications
for efficient spin-direction couplers. Here we demonstrate, both theoretically
and experimentally, that the transverse spin of surface elastic (Rayleigh)
waves has an anomalous sign near the surface, opposite to that in the case of
electromagnetic, sound, or water surface waves. This anomalous sign appears due
to the hybrid (neither transverse nor longitudinal) nature of elastic surface
waves. Furthermore, we show that this sign anomaly can be employed for the
selective spin-controlled excitation of symmetric and antisymmetric Lamb modes
propagating in opposite directions in an elastic plate. Our results pave the
way for spin-controlled manipulation of elastic waves and can be important for
a variety of areas, from phononic spin-based devices to seismic waves.",2308.01953v1
2014-09-03,A number theoretical observation of a resonant interaction of Rossby waves,"Rossby waves are generally expected to dominate the $\beta$ plane dynamics in
geophysics, and here in this paper we give a number theoretical observation of
the resonant interaction with a Diophantine equation. The set of resonant
frequencies does not have any frequency on the horizontal axis. We also give
several clusters of resonant frequencies.",1409.1031v1
2001-02-05,Electronic theory for superconductivity in Sr$_2$RuO$_4$: triplet pairing due to spin-fluctuation exchange,"Using a two-dimensional Hubbard Hamiltonian for the three electronic bands
crossing the Fermi level in Sr$_2$RuO$_4$ we calculate the band structure and
spin susceptibility $\chi({\bf q}, \omega)$ in quantitative agreement with
nuclear magnetic resonance (NMR) and inelastic neutron scattering (INS)
experiments. The susceptibility has two peaks at {\bf Q}$_i = (2\pi/3, 2\pi/3)$
due to the nesting Fermi surface properties and at {\bf q}$_i = (0.6\pi, 0)$
due to the tendency towards ferromagnetism. Applying spin-fluctuation exchange
theory as in layered cuprates we determine from $\chi({\bf q}, \omega)$,
electronic dispersions, and Fermi surface topology that superconductivity in
Sr$_2$RuO$_4$ consists of triplet pairing. Combining the Fermi surface topology
and the results for $\chi({\bf q}, \omega)$ we can exclude $s-$ and $d-$wave
symmetry for the superconducting order parameter. Furthermore, within our
analysis and approximations we find that $f$-wave symmetry is slightly favored
over p-wave symmetry due to the nesting properties of the Fermi surface.",0102074v3
2004-03-15,Excitation hierarchy of the quantum sine-Gordon spin chain in strong magnetic field,"The magnetic excitation spectrum of copper pyrimidine dinitrate, a material
containing S=1/2 antiferromagnetic chains with alternating g-tensor and the
Dzyaloshinskii-Moriya interaction, and exhibiting a field-induced spin gap, is
probed using submillimeter wave electron spin resonance spectroscopy. Ten
excitation modes are resolved in the low-temperature spectrum, and their
frequency-field diagram is systematically studied in magnetic fields up to 25
T. The experimental data are sufficiently detailed to make a very accurate
comparison with predictions based on the quantum sine-Gordon field theory.
Signatures of three breather branches and a soliton, as well as those of
several multi-particle excitation modes are identified.",0403364v1
2004-09-15,The t-J model: From light to heavy doping,"The regions of hole concentrations $0 \leq x \alt 0.3$ and temperatures
$0.005|t| \leq T \leq 0.02|t|$ are studied in the t-J model of Cu-O planes of
perovskite high-$T_c$ superconductors. For this purpose self-energy equations
for hole and spin Green's functions are derived using Mori's projection
operator technique and these equations are self-consistently solved. The
calculated hole band transforms radically at $x\approx 0.08$. A narrow
low-concentration band with minima near $(\pm\frac{\pi}{2},\pm\frac{\pi}{2})$
is converted to a band resembling the case of weak electron correlations, with
the minimum at $(\pi,\pi)$ or $(0,0)$. The hole Fermi surface is respectively
changed from small ellipses at $(\pm\frac{\pi}{2},\pm\frac{\pi}{2})$ to a large
rhombus centered at $(\pi,\pi)$ or $(0,0)$. The decrease of the magnetic
susceptibility at the antiferromagnetic wave vector and spin correlations with
doping is determined by the growth of the frequency of spin excitations at this
momentum. The shape of the frequency dependence of the susceptibility depends
heavily on the hole damping and varies from a broad feature similar to that
observed in La$_{2-x}$Sr$_x$CuO$_4$ to a pronounced maximum which resembles the
normal-state resonance peak in YBa$_2$Cu$_3$O$_{7-y}$.",0409379v1
2004-11-04,Spin dynamics in the antiferromagnetic phase for electron-doped cuprate superconductors,"Based on the $t$-$t'$-$t''$-$J$ model we have calculated the dynamical spin
susceptibilities in the antiferromagnetic (AF) phase for electron-doped
cuprates, by use of the slave-boson mean-field theory and random phase
approximation. Various results for the susceptibilities versus energy and
momentum have been shown at different dopings. At low energy, except the
collective spin-wave mode around $(\pi,\pi)$ and 0, we have primarily observed
that new resonance peaks will appear around $(0.3\pi,0.7\pi)$ and equivalent
points with increasing doping, which are due to the particle-hole excitations
between the two AF bands. The peaks are pronounced in the transverse
susceptibility but not in the longitudinal one. These features are predicted
for neutron scattering measurements.",0411117v2
2007-01-26,Cold Attractive Spin Polarized Fermi Lattice Gases and the Doped Positive U Hubbard Model,"Experiments on polarized fermion gases performed by trapping ultracold atoms
in optical lattices, allow the study of an attractive Hubbard model for which
the strength of the on site interaction is tuned by means of a Feshbach
resonance. Using a well-known particle-hole transformation we discuss how
results obtained for this system can be reinterpreted in the context of a doped
repulsive Hubbard model. In particular we show that the
Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state corresponds to the striped state
of the two-dimensional doped positive U Hubbard model. We then use the results
of numerical studies of the striped state to relate the periodicity of the FFLO
state to the spin polarization. We also comment on the relationship of the
$d_{x^2-y^2}$ superconducting phase of the doped 2D repulsive Hubbard model to
a d-wave spin density wave state for the attractive case.",0701649v1
1997-06-01,How to Probe for Dynamical Structure in the Collapse of Entangled States Using Nuclear Magnetic Resonance,"The spin state of two magnetically inequivalent protons in contiguous atoms
of a molecule becomes entangeled by the indirect spin-spin interaction
(j-coupling). The degree of entanglement oscillates at the beat frequency
resulting from the splitting of a degeneracy. This beating is manifest in NMR
spectroscopy as an envelope of the transverse magnetization and should be
visible in the free induction decay signal. The period (approximately 1 sec) is
long enough for interference between the linear dynamics and collapse of the
wave-function induced by a Stern-Gerlach inhomogeneity to significantly alter
the shape of that envelope. Various dynamical collapse theories can be
distinguished by their observably different predictions with respect to this
alteration. Adverse effects of detuning due to the Stern-Gerlach inhomogeneity
can be reduced to an acceptable level by having a sufficiently thin sample or a
strong rf field.",9706002v2
2009-01-12,Supersymmetric Valence Bond Solid States,"In this work we investigate the supersymmetric version of the valence bond
solid (SVBS) state. In one dimension, the SVBS states continuously interpolate
between the valence bond states for integer and half-integer spin chains, and
they generally describe superconducting valence bond liquid states. Spin and
superconducting correlation functions can be computed exactly for these states,
and their correlation lengths are equal at the supersymmetric point. In higher
dimensions, the wave function for the SVBS states can describe resonating
valence bond states (RVB). The SVBS states for the spin models are shown to be
precisely analogous to the bosonic Pfaffian states of the quantum Hall effect.
We also give microscopic Hamiltonians for which the SVBS state is the exact
ground state.",0901.1498v3
2009-02-13,From magnetism to one-dimensional spin liquid in the anisotropic triangular lattice,"We investigate the anisotropic triangular lattice that interpolates from
decoupled one-dimensional chains to the isotropic triangular lattice and has
been suggested to be relevant for various quasi-two-dimensional materials, such
as Cs$_2$CuCl$_4$ or $\kappa$-(ET)$_2$Cu$_2$(CN)$_3$, an organic material that
shows intriguing magnetic properties. We obtain an excellent accuracy by means
of a novel representation for the resonating valence bond wave function with
both singlet and triplet pairing. This approach allows us to establish that the
magnetic order is rapidly destroyed away from the pure triangular lattice and
incommensurate spin correlations are short range. A non-magnetic spin liquid
naturally emerges in a wide range of the phase diagram, with strong
one-dimensional character. The relevance of the triplet pairing for
$\kappa$-(ET)$_2$Cu$_2$(CN)$_3$ is also discussed.",0902.2338v1
2010-03-08,Anisotropic and quasipropagating spin excitations in superconducting Ba(Fe0.926Co0.074)2As2,"Inelastic neutron scattering from superconducting (SC)
Ba(Fe$_{0.926}$Co$_{0.074}$)$_2$As$_2$ reveals anisotropic and
quasi-two-dimensional (2D) magnetic excitations close to
\textbf{Q}$_{\texttt{AFM}}=({1}{2}/{1}{2})$ - the 2D antiferromagnetic (AFM)
wave-vector of the parent BaFe$_2$As$_2$ compound. The correlation length
anisotropy of these low energy fluctuations is consistent with spin nematic
correlations in the $J_1$-$J_2$ model with $J_1/J_2 \sim$ 1. The spin resonance
at $\sim$8.3 meV in the SC state displays the same anisotropy. The anisotropic
fluctuations experimentally evolve into two distinct maxima only along the
direction transverse to \textbf{Q}$_{\texttt{AFM}}$ above $\sim$80 meV
indicating unusual quasi-propagating excitations.",1003.1687v4
2010-07-21,Baryon-Baryon Interactions in the Flavor SU(3) Limit from Full QCD Simulations on the Lattice,"We investigate baryon-baryon (BB) interactions in the 3-flavor full QCD
simulations with degenerate quark masses for all flavors. The BB potentials in
the orbital S-wave are extracted from the Nambu-Bethe-Salpeter wave functions
measured on the lattice. We observe strong flavor-spin dependences of the BB
potentials at short distances. In particular, a strong repulsive core exists in
the flavor-octet and spin-singlet channel (the 8_s representation), while an
attractive core appears in the flavor singlet channel (the 1 representation).
We discuss a relation of such flavor-spin dependence with the Pauli exclusion
principle in the quark level. Possible existence of an H-dibaryon resonance
above the Lambda-Lambda threshold is also discussed.",1007.3559v1
2010-11-08,Flavor structure of the baryon-baryon interaction from lattice QCD,"We investigate baryon-baryon (BB) interactions in the 3-flavor full QCD
simulations with degenerate quark masses for all flavors. The BB potentials in
the orbital S-wave are extracted from the Nambu-Bethe-Salpeter wave functions
measured on the lattice. We observe strong flavor-spin dependences of the BB
potentials at short distances. In particular, a strong repulsive core exists in
the flavor-octet and spin-singlet channel(the 8_s representation), while an
attractive core appears in the flavor singlet channel (the 1 representation).
We discuss the relation of such flavor-spin dependence with the Pauli exclusion
principle at the quark level. The possible existence of an H-dibaryon resonance
above the Lambda-Lambda threshold is also discussed.",1011.1695v1
2010-11-23,A coupled quantum dot laser amplifier: Raman transitions between spin singlet and triplet states,"A holy grail of photonics research is the realization of a laser that uses a
single quantum emitter as the gain medium. Such a device would exhibit a
plethora of new features, including lasing without a well-defined threshold and
output intensity fluctuations that remain below the shot-noise limit. While
single-atom lasers have been demonstrated, compact devices capable of
continuous-wave operation require monolithic structures involving a solid-state
quantum emitter. Here, we report the observation of steady-state laser
amplification in Raman transitions between the lowest-energy entangled spin
states of a quantum-dot molecule. Absorption and resonance fluorescence
experiments demonstrate that the singlet and triplet states have
electric-dipole coupling to a common optically excited state. Fast spin
relaxation ensures population inversion on the triplet transition when the
singlet transition is driven resonantly. By embedding the quantum-dot molecule
in a cavity of modest quality factor, a solid-state single-emitter laser could
be realized.",1011.5203v1
2011-02-15,Magnetic and superconducting instabilities in a hybrid model of itinerant/localized electrons for iron pnictides,"We study a unified mechanism for spin-density-wave (SDW) and
superconductivity in a minimal model, in which itinerant electrons and local
moments coexist as previously proposed for the iron pnictides [EPL, 88, 17010
(2009)]. The phase diagram obtained at the mean field level is in qualitative
agreement with the experiment, which shows how the magnetic and superconducting
(SC) instabilities are driven by the critial coupling between the
itinerant/localized electrons. The spin and charge response functions at the
random phase approximation (RPA) level further characterize the dynamical
evolution of the system. In particular, the dynamic spin susceptibility
displays a Goldstone mode in the SDW phase, which evolves into a gapped
resonance-like mode in the superconducting phase. The latter persists all the
way into the normal state above Tc, where a strong scattering between the
itinerant electrons and local moments is restored, as an essential feature of
the model.",1102.3200v2
2011-05-15,Enhancing or suppressing spin Hall effect of light in layered nanostructures,"The spin Hall effect (SHE) of light in layered nanostructures is investigated
theoretically in this paper. A general propagation model describing the
spin-dependent transverse splitting in the SHE of light is established from the
viewpoint of classical electrodynamics. We show that the transverse
displacement of wave-packet centroid can be tuned to either a negative or a
positive value, or even zero, by just adjusting the structure parameters,
suggesting that the SHE of light in layered nanostructures can be enhanced or
suppressed in a desired way. The inherent secret behind this interesting
phenomenon is the optical Fabry-Perot resonance in the layered nanostructure.
We believe that these findings will open the possibility for developing new
nano-photonic devices.",1105.2936v4
2011-11-01,New results on the search for spin-exotic mesons with COMPASS,"The COMPASS fixed-target experiment at the CERN-SPS studies the structure and
spectrum of hadrons. One important goal using hadron beams is the search for
new states, in particular spin-exotic mesons and glueballs. As a first input to
the puzzle, COMPASS observed a significant $J^{PC}$ spin-exotic signal in the
2004 pilot run data (190\,GeV/$c$ $\pi^{-}$ beam, Pb target) in three charged
pion final states consistent with the disputed $\pi_1(1600)$. We started our
hadron spectroscopy programme in 2008 by collecting very high statistics using
a 190 GeV/$c$ negative pion beam scattered off a liquid hydrogen (proton)
target. The current status and new results from the 2008 data on the search for
the $\pi_1(1600)$ resonance with exotic $J^{PC}=1^{-+}$ quantum numbers
obtained from partial-wave analyses of the $\rho\pi$ and $\eta'\pi$ decay
channels are presented.",1111.0259v2
2012-03-14,Temperature dependence of in-plane correlation lengths in exchange biased Co/FeF2,"We have measured resonant soft x-ray diffuse magnetic scattering as a
function of temperature in a positively exchange biased Co/FeF2 bilayer and
analyzed the data in the distorted wave Born approximation to obtain in-plane
charge and magnetic correlation lengths associated with the Co and FeF2 layers
and estimate interfacial roughness. Tuning to the Fe and Co L3 edges reveals
significantly different temperature trends in these quantities in the
antiferromagnetic and ferromagnetic layers, respectively. While the magnetic
correlation length of the uncompensated interfacial spins in FeF2 layer
increase as temperature decreases, these quantities remain unchanged in the Co
layer. Our results indicate that uncompensated Fe spins order within a range of
few hundred nanometers in otherwise randomly distributed uncompensated magnetic
moments, giving rise to spin clusters in the antiferromagnet whose size
increase as the temperature decrease.",1203.3231v1
2013-12-09,Spectroscopic study of the magnetic ground state of Nb$_{1-y}$Fe$_{2+y}$,"We have investigated single crystals and polycrystals from the series
Nb$_{1-y}$Fe$_{2+y}$, $-0.004 \leq y \leq 0.018$ by electron spin resonance,
muon spin relaxation and M\""ossbauer spectroscopy. Our data establish that at
lowest temperatures all samples exhibit bulk magnetic order. Slight Fe-excess
induces low-moment ferromagnetism, consistent with bulk magnetometry ($\simeq
0.06 ~\mu_B/{\rm Fe}$), Nb--rich and stoichiometric NbFe$_2$ display spin
density wave order with small magnetic moment amplitudes of the order $\sim
0.001 - 0.01 ~\mu_B/{\rm Fe}$. This provides microscopic evidence for a
modulated magnetic state on the border of ferromagnetism in NbFe$_2$.",1312.2357v4
2014-10-30,Optical control of spin textures in quasi-one-dimensional polariton condensates,"We investigate, through polarization-resolved spectroscopy, the spin
transport by propagating polariton condensates in a quasi one-dimensional
microcavity ridge along macroscopic distances. Under circularly polarized,
continuous-wave, non-resonant excitation, a sinusoidal precession of the spin
in real space is observed, whose phase depends on the emission energy. The
experiments are compared with simulations of the spinor-polariton condensate
dynamics based on a generalized Gross-Pitaevskii equation, modified to account
for incoherent pumping, decay and energy relaxation within the condensate.",1410.8417v2
2015-01-04,Hybrid opto-mechanical systems with nitrogen-vacancy centers,"In this review, we briefly overview recent works on hybrid (nano)
opto-mechanical systems that contain both mechanical oscillators and diamond
nitrogen-vacancy (NV) centers. We review two different types of mechanical
oscillators. The first one is a clamped mechanical oscillator, such as a
cantilever, with a fixed frequency. The second one is an optically trapped
nano-diamond with a build-in nitrogen-vacancy center. By coupling mechanical
resonators with electron spins, we can use the spins to control the motion of
mechanical oscillators. For the first setup, we discuss two different coupling
mechanisms which are magnetic coupling and strain induced coupling. We
summarize their applications such as cooling the mechanical oscillator,
generating entanglements between NV centers, squeezing spin ensembles and et
al. For the second setup, we discuss how to generate quantum superposition
states with magnetic coupling, and realize matter wave interferometer. We will
also review its applications as ultra-sensitive mass spectrometer. Finally, we
discuss new coupling mechanisms and applications of the field.",1501.00636v1
2015-04-21,Anisotropic interactions opposing magnetocrystalline anisotropy in Sr$_3$NiIrO$_6$,"We report our investigation of the electronic and magnetic excitations of
Sr$_3$NiIrO$_6$ by resonant inelastic x-ray scattering at the Ir L$_3$ edge.
The intra-$t_{2g}$ electronic transitions are analyzed using an atomic model,
including spin-orbit coupling and trigonal distortion of the IrO$_6$
octahedron, confronted to {\it ab initio} quantum chemistry calculations. The
Ir spin-orbital entanglement is quantified and its implication on the magnetic
properties, in particular in inducing highly anisotropic magnetic interactions,
is highlighted. These are included in the spin-wave model proposed to account
for the dispersionless magnetic excitation that we observe at 90 meV. By
counterbalancing the strong Ni$^{2+}$ easy-plane anisotropy that manifests
itself at high temperature, the anisotropy of the interactions finally leads to
the remarkable easy-axis magnetism reported in this material at low
temperature.",1504.05420v2
2015-07-13,Masses of Heavy and Light Scalar Tetraquarks in a Non-Relativistic Quark Model,"Scalar tetraquark states are studied within the diquark-antidiquark picture
in a non-relativistic approach. We consider two types of confining potentials,
a quadratic and a linear one, to which we also add spin-spin, isospin-isospin,
and spin-isospin interactions. We calculate the masses of the scalar diquarks
and of the ground-state open and hidden charmed and bottom scalar tetraquarks.
Our results indicate that the scalar resonances $D_{0}^{\ast}(2400)$ and
$D_{s}(2632)$ have a sizable tetraquark amount in their wave function, while,
on the other hand, it turns out that the scalar states $D_{s0}^{\ast}(2317)$
and $X(3915)$ should not be considered as being predominantly
diquark-antidiquark bound states. We also investigate the masses of light
scalar diquarks and tetraquarks, which are comparable to the measured masses of
the light scalar mesons.",1507.03345v2
2015-09-26,Spin-Orbit Misalignment of Two-Planet-System KOI-89 Via Gravity Darkening,"We constrain the true spin-orbit alignment of the KOI-89 system by
numerically fitting the two \emph{Kepler} photometric lightcurves produced by
transiting planets KOI-89.01 and KOI-89.02. The two planets have periods of
84.69 days and 207.58 days, respectively. We find that the two bodies are
low-density giant planets with radii $0.45 \pm 0.03~\mathrm{R_{jup}}$ and $0.43
\pm 0.05~\mathrm{R_{jup}}$ and spin-orbit misalignments $72^{\circ} \pm
3^\circ$ and $73^{\circ+11}_{-5}$, respectively. Via dynamic stability tests we
demonstrate the general trend of higher system stability with the two planets
close to mutual alignment and estimate their coalignment angle to $20^\circ \pm
20^\circ$ -- i.e. the planets are misaligned with the star but may be aligned
with each other. From these results, we limit KOI-89's misalignment mechanisms
to star-disk-binary interactions, disk warping via planet-disk interactions,
planet-planet scattering, Kozai resonance, or internal gravity waves.",1509.07930v2
2016-10-11,Strong anisotropy within a Heisenberg model in the J=1/2 insulating state of Sr2Ir0.8Ru0.2O4,"The dispersive magnetic excitations in Sr2IrO4 have previously been well
described within an isospin-1/2 Heisenberg model on a square lattice that
revealed parallels with La2CuO4. Here we investigate the inelastic spectra of
Sr2Ir0.8Ru0.2O4 with resonant inelastic x-ray scattering (RIXS) at the Ir
L3-edge. The results are well described using linear spin-wave theory within a
similar Heisenberg model applicable to Sr2IrO4, however the disorder induced by
the substitution of 20% Ir4+ ions for Ru4+ removes longer range exchange
interactions. A large spin-gap (40 meV) is measured indicating strong
anisotropy from spin-orbit coupling that is manifest due to the altered
magnetic structure in Sr2Ir0.8Ru0.2O4 with c-axis aligned moments compared to
the basal plane moments in the parent. Collectively the results indicate the
robustness of a Heisenberg model description even when the magnetic structure
is altered and the J=1/2 moments diluted.",1610.03399v1
2018-05-29,A possible interpretation of the newly observed $Ω(2012)$ state,"Inspired by the newly observed $\Omega(2012)$ state at Belle II, we
investigate the two-body strong decays of $\Omega$ baryons up to $N=2$ shell
within the chiral quark model. Our results indicate that: (i) the newly
observed $\Omega(2012)$ state could be assigned to the spin-parity $J^P=3/2^-$
state $|70,^210,1,1,\frac{3}{2}^-\rangle$ and the experimental data can be
reasonably described. However, the spin-parity $J^P=1/2^-$ state
$|70,^210,1,1,\frac{1}{2}^-\rangle$ and spin-parity $J^P=3/2^+$ state
$|56,^410,2,0,\frac{3}{2}^+\rangle$ can't be completely excluded. (ii) The
$D$-wave states in the $N=2$ shell are most likely to be narrow states with a
width of dozens of MeV and have a good potential to be observed in the $\Xi K$
and/or $\Xi(1530)K$ channels in future experiments. The $\Omega(2250)$
resonance listed in PDG may be a good candidate of the $J^P=5/2^+$ $1D$ wave
state $|56,^410,2,2,5/2^+\rangle$.",1805.11285v1
2018-06-25,Painting Non-Classical States of Spin or Motion with Shaped Single Photons,"We propose a robust scheme for generating macroscopic superposition states of
spin or motion with the aid of a single photon. Shaping the wave packet of the
photon enables high-fidelity preparation of non-classical states of matter even
in the presence of photon loss. Success is heralded by photodetection, enabling
the scheme to be implemented with a weak coherent field. We analyze
applications to preparing Schr\""{o}dinger cat states of a collective atomic
spin or of a mechanical oscillator coupled to an optical resonator. The method
generalizes to preparing arbitrary superpositions of coherent states, enabling
full quantum control. We illustrate this versatility by showing how to prepare
Dicke or Fock states, as well as superpositions in the Dicke or Fock basis.",1806.09704v1
2018-02-19,Static properties and current-induced dynamics of pinned $90$ degree magnetic domain walls under applied fields: an analytic approach,"Magnetic domain walls are pinned strongly by abrupt changes in magnetic
anisotropy. When driven into oscillation by a spin-polarized current, locally
pinned domain walls can be exploited as tunable sources of short-wavelength
spin waves. Here, we develop an analytical framework and discrete Heisenberg
model to describe the static and dynamic properties of pinned domain walls with
a head-to-tail magnetic structure. We focus on magnetic domain walls that are
pinned by 90$^\circ$ rotations of uniaxial magnetic anisotropy. Our model
captures the domain wall response to a spin-transfer torque that is exerted by
an electric current. Model predictions of the domain wall resonance frequency
and its evolution with magnetic anisotropy strength and external magnetic field
are compared to micromagnetic simulations.",1802.06741v3
2019-02-22,Roton-induced Bose polaron in the presence of synthetic spin-orbit coupling,"We theoretically investigate the quasiparticle (polaron) properties of an
impurity immersing in a Bose-Einstein condensate with equal Rashba and
Dresselhaus spin-orbit coupling at zero temperature. In the presence of
spin-orbit coupling, all bosons can condense into a single plane-wave state
with finite momentum, and the corresponding excitation spectrum shows an
intriguing roton minimum. We find that the polaron properties are strongly
modified by this roton minimum, where the ground state of attractive polaron
acquires a nonzero momentum and anisotropic effective mass. Across the
resonance of the interaction between impurity and atoms, the polaron evolves
into a tight-binding dimer. We show that the evolution is not smooth when the
roton structure of the condensate becomes apparent, and a first-order phase
transition from a phonon-induced polaron to a roton-induced polaron is observed
at a critical interaction strength.",1902.08333v1
2020-04-20,Probing spin correlations in a Bose-Einstein condensate near the single atom level,"Using parametric conversion induced by a Shapiro-type resonance, we produce
and characterize a two-mode squeezed vacuum state in a sodium spin 1
Bose-Einstein condensate. Spin-changing collisions generate correlated pairs of
atoms in the $m=\pm 1$ Zeeman states out of a condensate with initially all
atoms in $m=0$. A novel fluorescence imaging technique with sensitivity $\Delta
N \sim 1.6$ atom enables us to demonstrate the role of quantum fluctuations in
the initial dynamics and to characterize the full distribution of the final
state. Assuming that all atoms share the same spatial wave function, we infer a
squeezing parameter of 15.3\,dB.",2004.09003v3
2020-08-11,Itinerant ferromagnetism in the repulsive Hubbard chain with anisotropic odd-wave attraction,"The ground-state properties of the Hubbard chain with on-site repulsion and
anisotropic nearest-neighbor attraction are investigated by means of density
matrix renormalization group calculations. The non-local attraction acts
between fermions of one spin component only, mimicking the effect of p-wave
Feshbach resonances in cold-atom systems. We analyze the onset of itinerant
ferromagnetism, pinpointing the critical attraction strength where partially
and fully ferromagnetic states occur. In the cold-atom setup, where the two
(pseudo) spin populations are separately conserved, ferromagnetism occurs with
the nucleation of a fully imbalanced band-insulating domain hosting the
attractive component only. The size of this domain grows with the attraction
strength, therefore increasing the (opposite) imbalance of the other domain,
until the two spin components are fully separated. In the presence of a
harmonic trap, the ferromagnetic state hosts a partially imbalanced domain in
the center with an excess of the attractive component and filling lower than
one. This central region is surrounded by fully imbalanced domains, located in
the trap tails, hosting only fermions belonging to the other component.",2008.04588v1
2016-03-29,Coherent Charge and Spin Density Waves in Underdoped HgBa$_{2}$CuO$_{4+δ}$,"Various forms of spin and charge ordering have been identified in a wide
range of cuprate superconducting materials, but whether these behaviors are
ubiquitous phenomena is not established. In this work we focus on one of the
simplest compounds, HgBa$_{2}$CuO$_{4+\delta}$ (Hg1201), a superconductor with
a high transition temperature, 97 K, having only a single layer and tetragonal
structure, in contrast to one of the most extensively studied materials,
YBa$_{2}$Cu$_{3}$O$_{6+y}$ (Y123). Using nuclear magnetic resonance we have
discovered a coherent spatial modulation of both spin and charge that is
temperature and magnetic field independent, in competition with
superconductivity similar to other cuprates. However, there is no evidence for
the magnetic field and temperature induced charge order observed in Y123.
Electronic instabilities are a common feature of cuprates as in the present
work on Hg1201, but their manifestations are not universal.",1603.08839v1
2018-04-25,High-Field Magnetoresistance of Organic Semiconductors,"The magneto-electronic field effects in organic semiconductors at high
magnetic fields are described by field-dependent mixing between singlet and
triplet states of weakly bound charge carrier pairs due to small differences in
their Land\'e g-factors that arise from the weak spin-orbit coupling in the
material. In this work, we corroborate theoretical models for the high-field
magnetoresistance of organic semiconductors, in particular of diodes made of
the conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonate)
(PEDOT:PSS) at low temperatures, by conducting magnetoresistance measurements
along with multi-frequency continuous-wave electrically detected magnetic
resonance experiments. The measurements were performed on identical devices
under similar conditions in order to independently assess the magnetic
field-dependent spin-mixing mechanism, the so-called {\Delta}g mechanism, which
originates from differences in the charge-carrier g-factors induced by
spin-orbit coupling.",1804.09297v1
2020-11-27,Mapping out the spin fluctuations in Co-doped LaFeAsO single crystals by NMR,"We determine the phase diagram of LaFe$_{1-x}$Co$_x$AsO single crystals by
using nuclear magnetic resonance (NMR). Up to a nominal doping of $x=0.03$, it
follows the phase diagram for F-doped polycrystals. Above $x=0.03$, the F-doped
samples become superconducting, whereas for Co-doping the structural and
magnetic transitions can be observed up to $x=0.042$, and superconductivity
occurs only for higher doping levels and with reduced transition temperatures.
For dopings up to $x=0.056$, we find evidence for short-range magnetic order.
By means of relaxation-rate measurements, we map out the magnetic fluctuations
that reveal the interplay of nematicity and magnetism. Above the nematic
ordering, the spin fluctuations in LaFe$_{1-x}$Co$_x$AsO are identical to those
in Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$, suggesting that nematicity in LaFeAsO is a
result of the fluctuating spin density wave as well.",2011.13641v1
2004-05-25,Magnetic induction and domain walls in magnetic thin films at remanence,"Magnetic domain walls in thin films can be well analyzed using polarized
neutron reflectometry. Well defined streaks in the off-specular spin-flip
scattering maps are explained by neutron refraction at perpendicular N\'{e}el
walls. The position of the streaks depends only on the magnetic induction
within the domains, whereas the intensity of the off-specular magnetic
scattering depends on the spin-flip probability at the domain walls and on the
average size of the magnetic domains. This effect is fundamentally different
and has to be clearly distinguished from diffuse scattering originating from
the size distribution of magnetic domains. Polarized neutron reflectivity
experiments were carried out using a $^3$He gas spin-filter with a analyzing
power as high as 96% and a neutron transmission of approx 35%. Furthermore, the
off-specular magnetic scattering was enhanced by using neutron resonance and
neutron standing wave techniques.",0405586v2
2016-11-08,Low-energy spin excitations in Li(0.8)Fe(0.2)ODFeSe superconductor studied with inelastic neutron scattering,"We report an inelastic neutron scattering study of single crystals of
(Li$_{0.8}$Fe$_{0.2}$)ODFeSe. Temperature-dependent low-energy spin excitations
are observed near $\mathbf{Q}=$ (0.5, 0.27, 0.5) and equivalent wave vectors
symmetrically surrounding $\mathbf{Q}=$ (0.5, 0.5, 0.5) in the 1-Fe Brillouin
zone, consistent with a Fermi-surface-nesting description. The excitations are
broadly distributed in energy, ranging from 16 to 35 meV. Upon cooling below
the superconducting critical temperature ($T_\mathrm{c}$), magnetic response
below twice the superconducting gap $2\Delta_\mathrm{SC}$ exhibits an abrupt
enhancement, consistent with the notion of spin resonance, whereas the response
at higher energies increases more gradually with only a weak anomaly at
$T_\mathrm{c}$. Our results suggest that (Li$_{0.8}$Fe$_{0.2}$)ODFeSe might be
on the verge of a crossover between different Cooper-pairing channels with
distinct symmetries.",1611.02602v1
2019-12-19,Dissipation in extreme-mass ratio binaries with a spinning secondary,"We present the gravitational-wave flux balance law in an extreme mass-ratio
binary with a spinning secondary. This law relates the flux of energy (angular
momentum) radiated to null infinity and through the event horizon to the local
change in the secondary's orbital energy (angular momentum) for generic
(non-resonant) bound orbits in Kerr spacetime. As an explicit example we
compute these quantities for a spin-aligned body moving on a circular orbit
around a Schwarzschild black hole. We perform this calculation both
analytically, via a high-order post-Newtonian expansion, and numerically in two
different gauges. Using these results we demonstrate explicitly that our new
balance law holds.",1912.09461v2
2020-12-12,Magnetization Dynamics of Fibonacci-Distorted Kagome Artificial Spin Ice,"We present results of ferromagnetic resonance (FMR) experiments and
micromagnetic simulations for a distorted, 2D Kagome artificial spin ice. The
distorted structure is created by continuously modulating the 2D primitive
lattice translation vectors of a periodic honeycomb lattice, according to an
aperiodic Fibonacci sequence used to generate 1D quasicrystals. Experimental
data and micromagnetic simulations show the Fibonacci distortion causes
broadening and splitting of FMR modes into multiple branches, which accompany
the increasing number of segment lengths and orientations that develop with
increasing distortion. When the applied field is increased in the opposite
direction to the net magnetization of a segment, spin wave modes appear,
disappear or suddenly shift, to signal segment magnetization reversal events.
These results show the complex behavior of reversal events, as well as
well-defined frequencies and frequency-field slopes of FMR modes, can be
precisely tuned by varying the severity of the aperiodic lattice distortion.
This type of distorted structure could therefore provide a new tool for the
design of complicated magnonic systems.",2012.06837v1
2020-12-18,Spin and charge order in doped spin-orbit coupled Mott insulators,"We study a two-dimensional single band Hubbard Hamiltonian with antisymmetric
spin-orbit coupling. We argue that this is the minimal model to understand the
electronic properties of locally non-centrosymmetric transition-metal (TM)
oxides such as Sr$_2$IrO$_4$. Based on exact diagonalizations of small clusters
and the random phase approximation, we investigate the correlation effects on
charge and magnetic order as a function of doping and of the TM-oxygen-TM bond
angle $\theta$. For small doping and $\theta$ $\lesssim$ $15^\circ$ we find
dominant commensurate in-plane antiferromagnetic fluctuations while
ferromagnetic fluctuations dominate for $\theta$ $\gtrsim$ $25^\circ$.
Moderately strong nearest-neighbor Hubbard interactions can also stabilize a
charge density wave order. Furthermore, we compare the dispersion of magnetic
excitations for the hole-doped case to resonant inelastic X-ray scattering data
and find good qualitative agreement.",2012.10479v1
2022-06-09,Spin-orbit excitons and electronic configuration of the $5d^4$ insulator Sr$_3$Ir$_2$O$_7$F$_2$,"Here we report on the low-energy excitations within the paramagnetic
spin-orbit insulator Sr$_3$Ir$_2$O$_7$F$_2$ studied via resonant inelastic
X-ray scattering, \textit{ab initio} quantum chemical calculations, and
model-Hamiltonian simulations. This material is a unique $d^{4}$ Ir$^{5+}$
analog of Sr$_3$Ir$_2$O$_7$ that forms when F ions are intercalated within the
SrO layers spacing the square lattice IrO$_{6}$ bilayers of Sr$_3$Ir$_2$O$_7$.
Due to the large distortions about the Ir$^{5+}$ ions, our computations
demonstrate that a large single-ion anisotropy yields an $S$=1 ($L{\approx}$1,
$J{\approx}$0) ground state wave function. Weakly coupled, excitonic modes out
of the $S_z$=0 ground state are observed and are well-described by a
phenomenological spin-orbit exciton model previously developed for $3d$ and
$4d$ transition metal ions. The implications of our results regarding the
interpretation of previous studies of hole-doped iridates close to $d^{4}$
fillings are discussed.",2206.04721v1
2022-06-13,The remarkable prospect for quantum-dot-coupled tin qubits in silicon,"Spin-$\frac{1}{2}$ $^{119}$Sn nuclei in a silicon semiconductor could make
excellent qubits. Nuclear spins in silicon are known to have long coherence
times. Tin is isoelectronic with silicon, so we expect electrons can easily
shuttle from one Sn atom to another to propagate quantum information via a
hyperfine interaction that we predict, from all-electron linearized augmented
plane wave density functional theory calculations, to be roughly ten times
larger than intrinsic $^{29}$Si. A hyperfine-induced electro-nuclear
controlled-phase (e-n-CPhase) gate operation, generated (up to local rotations)
by merely holding an electron at a sweet-spot of maximum hyperfine strength for
a specific duration of time, is predicted to be exceptionally resilient to
charge/voltage noise. Diabatic spin flips are suppressed with a modest magnetic
field ($>15~$mT for $<10^{-6}$ flip probabilities) and nuclear spin bath noise
may be avoided via isotopic enrichment or mitigated using dynamical decoupling
or through monitoring and compensation. Combined with magnetic resonance
control, this operation enables universal quantum computation.",2206.06285v1
2022-06-23,Time Translation Symmetry Breaking in an Isolated Spin-Orbit-Coupled Fluid of Light,"We study the interplay between intrinsic spin-orbit coupling and nonlinear
photon-photon interactions in a nonparaxial, elliptically polarized fluid of
light propagating in a bulk Kerr medium. We find that in situations where the
nonlinear interactions induce birefringence, i.e., a polarization-dependent
nonlinear refractive index, their interplay with spin-orbit coupling results in
an interference between the two polarization components of the fluid traveling
at different wave vectors, which entails the breaking of translation symmetry
along the propagation direction. This phenomenon leads to a Floquet band
structure in the Bogoliubov spectrum of the fluid, and to characteristic
oscillations of its intensity correlations. We characterize these oscillations
in detail and point out their exponential growth at large propagation
distances, revealing the presence of parametric resonances.",2206.11714v2
2022-10-21,Veneziano Variations: How Unique are String Amplitudes?,"String theory offers an elegant and concrete realization of how to
consistently couple states of arbitrarily high spin. But how unique is this
construction? In this paper we derive a novel, multi-parameter family of
four-point scattering amplitudes exhibiting i) polynomially bounded high-energy
behavior and ii) exchange of an infinite tower of high-spin modes, albeit with
a finite number of states at each resonance. These amplitudes take an
infinite-product form and, depending on parameters, exhibit mass spectra that
are either unbounded or bounded, thus corresponding to generalizations of the
Veneziano and Coon amplitudes, respectively. For the bounded case, masses
converge to an accumulation point, a peculiar feature seen in the Coon
amplitude but more recently understood to arise naturally in string theory.
Importantly, our amplitudes contain free parameters allowing for the
customization of the slope and offset of the spin-dependence in the Regge
trajectory. We compute all partial waves for this multi-parameter class of
amplitudes and identify unitary regions of parameter space. For the unbounded
case, we apply similar methods to derive new deformations of the Veneziano and
Virasoro-Shapiro amplitudes.",2210.12163v2
2022-11-29,Ground states and magnonics in orthogonally-coupled symmetric all-antiferromagnetic junctions,"In this work, the rich ground-state structure of orthogonally-coupled
symmetric all-antiferromagnetic junctions with easy-plane anisotropy is
reported. Spin reorientation process rather than the traditional spin flop (SF)
occurs, resulting in a novel phase in which N\'{e}el vectors preserve the
mirror-reflection symmetry (termed as ``MRS phase""). The phase transitions
between SF and MRS phases can be either the first- or second-order. After
disturbed by external stimuli, magnons with different parities emerge. For
in-plane dc fields, no couplings between magnons occur. When dc fields become
oblique, coherent couplings between magnons with opposite parity emerge,
leading to anticrossings in resonance frequencies. However, self-hybridization
among magnons with the same parity never happens. More interestingly, spin
waves based on MRS phase are linearly polarized and their polarization
directions can be fine controlled.",2211.16063v1
2023-07-29,Single-spin spectroscopy of spontaneous and phase-locked spin torque oscillator dynamics,"We employ N-$V$ magnetometry to measure the stray field dynamics of a
ferromagnetic permalloy nanowire driven by spin-orbit torques. Specifically, we
observe the optically detected magnetic resonance (ODMR) signatures of both
spontaneous DC-driven magnetic oscillations and phase-locking to a second
harmonic drive, developing a simple macrospin model that captures the salient
features. We also observe signatures of dynamics beyond the macrospin model,
including an additional ODMR feature (associated with a second SW mode) and one
mode sapping power from another. Our results provide additional insight into
N-$V$-spin wave coupling mechanisms, and represent a new modality for
sub-wavelength N-$V$ scanned probe microscopy of nanoscale magnetic
oscillators.",2307.16049v1
2023-10-11,Frequency mixing spectroscopy of spins in diamond,"Frequency mixing processes in spin systems have a variety of applications in
meteorology and in quantum data processing. Spin spectroscopy based on
frequency mixing offers some advantages, including the ability to eliminate
crosstalk between driving and detection. We experimentally explore nonlinear
frequency mixing processes with negatively charged nitrogen-vacancy defects in
diamond at low temperatures, and near level anti crossing. The experimental
setup allows simultaneously applying magnetic driving in the longitudinal and
transverse directions. Magnetic resonance detection is demonstrated using both
Landau Zener St\""uckelberg interferometry and two-tone driving spectroscopy.
The experimental results are compared with predictions of a theoretical
analysis based on the rotating wave approximation.",2310.07398v2
2011-02-11,New resonance-polariton Bose-quasiparticles enhances optical transmission into nanoholes in metal films,"We argue the existence of fundamental particles in nature, neutral
Light-Particles with spin 1, and rest mass $m=1.8\cdot 10^{-4} m_e$, in
addition to electrons, neutrons and protons. We call these particles Light
Bosons because they create the electromagnetic field which represents Planck's
gas of massless photons together with a gas of Light Particles in the
condensate. In this respect, the condensed Light Particles, having no magnetic
field, represent the constant electric field. In this context, we predict a
existence of plasmon-polariton and resonance-polariton Bose-quasiparticles with
effective masses $m_l\approx 10^{-6} m_e$ and $m_r=0.5m_e$, which are induced
by interaction of the plasmon field and the resonance Fr$\ddot o$lich-
Schafroth charged bosons with electromagnetic wave in metal. Also, we prove
that the enhancement optical transmission into nanoholes in metal films and
Surface Enhanced Raman Spectroscopy are provided by a new resonance-polariton
Bose-quasiparticles but not model of surface plasmon-polariton. In this letter,
the quantization Fresnel's equations is presented which confirms that Light
Particles in the condensate are concentrated near on the wall of grooves in
metallic grating and, in turn, represent as the constant electric field which
provides the launching of the surface Fr\""olich- Schafroth bosons on the
surface metal holes.",1102.2292v1
2016-02-29,Resonances from QCD bound states and the 750 GeV diphoton excess,"Pair production of colored particles is in general accompanied by production
of QCD bound states (onia) slightly below the pair-production threshold. Bound
state annihilation leads to resonant signals, which in some cases are easier to
see than the decays of the pair-produced constituents. In a previous paper
(arXiv:1204.1119) we estimated the bound state signals, at leading order and in
the Coulomb approximation, for particles with various spins, color
representations and electric charges, and used 7 TeV ATLAS and CMS resonance
searches to set rough limits. Here we update our results to include 8 and 13
TeV data. We find that the recently reported diphoton excesses near 750 GeV
could indeed be due to a bound state of this kind. A narrow resonance of the
correct size could be obtained for a color-triplet scalar with electric charge
-4/3 and mass near 375 GeV, if (as a recent lattice computation suggests) the
wave function at the origin is somewhat larger than anticipated. Pair
production of this particle could have evaded detection up to now. Other
candidates may include a triplet scalar of charge 5/3, a triplet fermion of
charge -4/3, and perhaps a sextet scalar of charge -2/3.",1602.08819v3
2020-11-27,Radiofrequency spectroscopy of one-dimensional trapped Bose polarons: crossover from the adiabatic to the diabatic regime,"We investigate the crossover of the impurity-induced dynamics, in trapped
one-dimensional Bose polarons subject to radio frequency (rf) pulses of varying
intensity, from an adiabatic to a diabatic regime. Utilizing adiabatic pulses
for either weak repulsive or attractive impurity-medium interactions, a
multitude of polaronic excitations or mode-couplings of the impurity-bath
interaction with the collective breathing motion of the bosonic medium are
spectrally resolved. We find that for strongly repulsive impurity-bath
interactions, a temporal orthogonality catastrophe manifests in resonances in
the excitation spectra where impurity coherence vanishes. When two impurities
are introduced, impurity-impurity correlations, for either attractive or strong
repulsive couplings, induce a spectral shift of the resonances with respect to
the single impurity. For a heavy impurity, the polaronic peak is accompanied by
a series of equidistant side-band resonances, related to interference of the
impurity spin dynamics and the sound waves of the bath. In all cases, we enter
the diabatic transfer regime for an increasing bare Rabi frequency of the rf
field with a Lorentzian spectral shape featuring a single polaronic resonance.
The findings in this work on the effects of external trap, rf pulse and
impurity-impurity interaction should have implications for the new generations
of cold-atom experiments.",2011.13756v2
2020-05-30,Magnetization dynamics in proximity-coupled superconductor/ferromagnet/superconductor multilayers,"In this work, magnetization dynamics is studied in
superconductor/ferromagnet/superconductor three-layered films in a wide
frequency, field, and temperature ranges using the broad-band ferromagnetic
resonance measurement technique. It is shown that in presence of both
superconducting layers and of superconducting proximity at both
superconductor/ferromagnet interfaces a massive shift of the ferromagnetic
resonance to higher frequencies emerges. The phenomenon is robust and
essentially long-range: it has been observed for a set of samples with the
thickness of ferromagnetic layer in the range from tens up to hundreds of
nanometers. The resonance frequency shift is characterized by proximity-induced
magnetic anisotropies: by the positive in-plane uniaxial anisotropy and by the
drop of magnetization. The shift and the corresponding uniaxial anisotropy grow
with the thickness of the ferromagnetic layer. For instance, the anisotropy
reaches 0.27~T in experiment for a sample with 350~nm thick ferromagnetic
layer, and about 0.4~T in predictions, which makes it a ferromagnetic film
structure with the highest anisotropy and the highest natural resonance
frequency ever reported. Various scenarios for the superconductivity-induced
magnetic anisotropy are discussed. As a result, the origin of the phenomenon
remains unclear. Application of the proximity-induced anisotropies in
superconducting magnonics is proposed as a way for manipulations with a
spin-wave spectrum.",2006.00348v1
2022-10-25,Efimovian three-body potential from broad to narrow Feshbach resonances,"We analyse the change in the hyperradial Efimovian three-body potential as
the two-body interaction is tuned from the broad to narrow Feshbach resonance
regime. Here, it is known from both theory and experiment that the three-body
dissociation scattering length $a_-$ shifts away from the universal value of
$-9.7 \ r_{\mathrm{vdW}}$, with $r_{\mathrm{vdW}} = \frac{1}{2} \left(m
C_6/\hbar^2 \right)^{1/4}$ the two-body van der Waals range. We model the
three-body system using a separable two-body interaction that takes into
account the full zero-energy behaviour of the multichannel wave function. We
find that the short-range repulsive barrier in the three-body potential
characteristic for single-channel models remains universal for narrow
resonances, whilst the change in the three-body parameter originates from a
strong decrease in the potential depth. From an analysis of the underlying spin
structure we further attribute this behavior to the dominance of the two-body
interaction in the resonant channel compared to other background interactions.",2210.14200v3
2023-02-01,The tidal excitation of r modes in a solar type star orbited by a giant planet companion and the effect on orbital evolution I: The aligned case,"It has been suggested that tidal interaction is important for shaping the
orbital configurations of close orbiting giant planets. The excitation of
propagating waves and normal modes (dynamical tide) will be important for
estimating time scales for orbital evolution. We consider the tidal interaction
of a Jupiter mass planet orbiting a solar type primary. Tidal and rotational
frequencies are assumed comparable making the effect of rotation important.
Although centrifugal distortion is neglected, Coriolis forces are fully taken
into account. We focus in detail on the potentially resonant excitation of $r$
modes associated with spherical harmonics of degrees three and five. These are
mostly sited in the radiative core but with a significant response in the
convective envelope where dissipation occurs. Away from resonance significant
orbital evolution over the system lifetime is unlikely. However, tidal
interaction is enhanced near resonances and the orbital evolution accelerated
as they are passed through. This speed up may be sustained if near resonance
can be maintained. For close orbits with primaries rotating sufficiently
rapidly, this could arise from angular momentum loss and stellar spin down
through a stellar wind bringing about significant orbital evolution over the
system lifetime.",2302.00473v1
2023-03-27,Charmoniumlike tetraquarks in a chiral quark model,"The lowest-lying charmonium-like tetraquarks $c\bar{c}q\bar{q}$ $(q=u,\,d)$
and $c\bar{c}s\bar{s}$, with spin-parity $J^P=0^+$, $1^+$ and $2^+$, and
isospin $I=0$ and $1$, are systematically investigated within the theoretical
framework of complex-scaling range for a chiral quark model that has already
been successfully applied in former studies of various tetra- and penta-quark
systems. A four-body $S$-wave configuration which includes meson-meson,
diquark-antidiquark and K-type arrangements of quarks, along with all possible
color wave functions, is comprehensively considered. Several narrow resonances
are obtained in each tetraquark channel when a fully coupled-channel
computation is performed. We tentatively assign theoretical states to
experimentally reported charmonium-like signals such as $X(3872)$, $Z_c(3900)$,
$X(3960)$, $X(4350)$, $X(4685)$ and $X(4700)$. They can be well identified as
hadronic molecules; however, other exotic components which involve, for
instance, hidden-color channels or diquark-antidiquark structures play a
considerable role. Meanwhile, two resonances are obtained at $4.04$ GeV and
$4.14$ GeV which may be compatible with experimental data in the energy
interval $4.0-4.2$ GeV. Furthermore, the $X(3940)$ and $X(4630)$ may be
identified as color compact tetraquark resonances. Finally, we also find few
resonance states in the energy interval from $4.5$ GeV to $5.0$ GeV, which
would be awaiting for discovery in future experiments.",2303.15388v1
2018-03-13,Theory of nonreciprocal spin waves excitation in spin-Hall oscillators with Dzyaloshinkii-Moriya interaction,"A two-dimensional analytical model for the description of the excitation of
nonreciprocal spin waves by spin current in spin-Hall oscillators in the
presence of the interfacial Dzyaloshinskii-Moriya interaction (i-DMI) is
developed. The theory allows one to calculate the threshold current for the
excitation of spin waves, as well as the frequencies and spatial profiles of
the excited spin wave modes. It is found, that the frequency of the excited
spin waves exhibits a quadratic red shift with the i-DMI strength. At the same
time, in the range of small and moderate values of the i-DMI constant, the
averaged wave number of the excited spin waves is almost independent of the
i-DMI, which results in a rather weak dependence on the i-DMI of the threshold
current of the spin wave excitation. The obtained analytical results are
confirmed by the results of micromagnetic simulations.",1803.05061v1
2021-02-24,SU(4) spin waves in the $ν=\pm1$ quantum Hall ferromagnet in graphene,"We study generalized spin waves in graphene under a strong magnetic field
when the Landau-level filling factor is $\nu=\pm 1$. In this case, the ground
state is a particular SU(4) quantum Hall ferromagnet, in which not only the
physical spin is fully polarized but also the pseudo-spin associated with the
valley degree of freedom. The nature of the ground state and the spin-valley
polarization depend on explicit symmetry breaking terms that are also reflected
in the generalised spin-wave spectrum. In addition to pure spin waves, one
encounters valley-pseudo-spin waves as well as more exotic entanglement waves
that have a mixed spin-valley character. Most saliently, the SU(4)
symmetry-breaking terms do not only yield gaps in the spectra, but under
certain circumstances, namely in the case of residual ground-state symmetries,
render the originally quadratic (in the wave vector) spin-wave dispersion
linear.",2102.12438v1
2021-05-06,Spin Wave Interference Detection via Inverse Spin Hall Effect,"In this letter, we present experimental data demonstrating spin wave
interference detection using spin Hall effect (ISHE). Two coherent spin waves
are excited in a yttrium-iron garnet (YIG) waveguide by continuous microwave
signals. The initial phase difference between the spin waves is controlled by
the external phase shifter. The ISHE voltage is detected at a distance of 2 mm
and 4 mm away from the spin wave generating antennae by an attached Pt layer.
Experimental data show ISHE voltage oscillation as a function of the phase
difference between the two interfering spin waves. This experiment demonstrates
an intriguing possibility of using ISHE in spin wave logic circuit converting
spin wave phase into an electric signal",2105.02979v1
2022-07-06,Filtering and imaging of frequency-degenerate spin waves using nanopositioning of a single-spin sensor,"Nitrogen-vacancy (NV) magnetometry is a new technique for imaging spin waves
in magnetic materials. It detects spin waves by their microwave magnetic stray
fields, which decay evanescently on the scale of the spin-wavelength. Here, we
use nanoscale control of a single-NV sensor as a wavelength filter to
characterize frequency-degenerate spin waves excited by a microstrip in a
thin-film magnetic insulator. With the NV-probe in contact with the magnet, we
observe an incoherent mixture of thermal and microwave-driven spin waves. By
retracting the tip, we progressively suppress the small-wavelength modes until
a single coherent mode emerges from the mixture. In-contact scans at low drive
power surprisingly show occupation of the entire iso-frequency contour of the
two-dimensional spin-wave dispersion despite our one-dimensional microstrip
geometry. Our distance-tunable filter sheds light on the spin-wave band
occupation under microwave excitation and opens opportunities for imaging
magnon condensates and other coherent spin-wave modes.",2207.02798v1
2010-04-15,Schwinger Boson Mean Field Theories of Spin Liquid States on Honeycomb Lattice: Projective Symmetry Group Analysis and Critical Field Theory,"Motivated by the recent numerical evidence[1] of a short-range resonating
valence bond state in the honeycomb lattice Hubbard model, we consider
Schwinger boson mean field theories of possible spin liquid states on honeycomb
lattice. From general stability considerations the possible spin liquids will
have gapped spinons coupled to Z$_2$ gauge field. We apply the projective
symmetry group(PSG) method to classify possible Z$_2$ spin liquid states within
this formalism on honeycomb lattice. It is found that there are only two
relevant Z$_2$ states, differed by the value of gauge flux, zero or $\pi$, in
the elementary hexagon. The zero-flux state is a promising candidate for the
observed spin liquid and continuous phase transition into commensurate N\'eel
order. We also derive the critical field theory for this transition, which is
the well-studied O(4) invariant theory[2-4], and has an irrelevant coupling
between Higgs and boson fields with cubic power of spatial derivatives as
required by lattice symmetry. This is in sharp contrast to the conventional
theory[5], where such transition generically leads to non-colinear
incommensurate magnetic order. In this scenario the Z$_2$ spin liquid could be
close to a tricritical point. Soft boson modes will exist at seven different
wave vectors. This will show up as low frequency dynamical spin susceptibility
peaks not only at the $\Gamma$ point (the N\'eel order wave vector) but also at
Brillouin zone edge center $M$ points and twelve other points. Some simple
properties of the $\pi$-flux state are studies as well. Symmetry allowed
further neighbor mean field ansatz are derived in Appendix which can be used in
future theoretical works along this direction.",1004.2693v3
2021-02-04,Magnon-spinon dichotomy in the Kitaev hyperhoneycomb $β$-Li$_2$IrO$_3$,"The family of edge-sharing tri-coordinated iridates and ruthenates has
emerged in recent years as a major platform for Kitaev spin liquid physics,
where spins fractionalize into emergent magnetic fluxes and Majorana fermions
with Dirac-like dispersions. While such exotic states are usually pre-empted by
long-range magnetic order at low temperatures, signatures of Majorana fermions
with long coherent times have been predicted to manifest at intermediate and
higher energy scales, similar to the observation of spinons in quasi-1D spin
chains. Here we present a Resonant Inelastic X-ray Scattering study of the
magnetic excitations of the hyperhoneycomb iridate $\beta$-Li$_2$IrO$_3$ under
a magnetic field with a record-high-resolution spectrometer. At
low-temperatures, dispersing spin waves can be resolved around the predicted
intertwined incommensurate spiral and field-induced zigzag orders, whose
excitation energy reaches a maximum of 16meV. A 2T magnetic field softens the
dispersion around ${\bf Q}=0$. The behavior of the spin waves under magnetic
field is consistent with our semiclassical calculations for the ground state
and the dynamical spin structure factor, which further predicts that the ensued
intertwined uniform states remain robust up to very high fields (100 T). Most
saliently, the low-energy magnon-like mode is superimposed by a broad continuum
of excitations, centered around 35meV and extending up to 100meV. This
high-energy continuum survives up to at least 300K -- well above the ordering
temperature of 38K -- and gives evidence for pairs of long-lived Majorana
fermions of the proximate Kitaev spin liquid.",2102.02714v2
2014-07-31,Effect of pairing fluctuations on the spin resonance in Fe-based superconductors,"The spin resonance observed in the inelastic neutron scattering data on
Fe-based superconductors has played a prominent role in the quest for
determining the symmetry of the order parameter in these compounds. Most
theoretical studies of the resonance employ an RPA-type approach in the
particle-hole channel and associate the resonance in the spin susceptibility
$\chi_S (\mathbf{q}, \omega)$ at momentum ${\bf Q} = (\pi,\pi)$ with the
spin-exciton of an $s^{+-}$ superconductor, pulled below $2\Delta$ by residual
attraction associated with the sign change of the gap between Fermi points
connected by ${\bf Q}$. Here we explore the effect of fluctuations in the
particle-particle channel on the spin resonance. Particle-particle and
particle-hole channels are coupled in a superconductor and to what extent the
spin resonance can be viewed as a particle-hole exciton needs to be addressed.
In the case of purely repulsive interactions we find that the particle-particle
channel at total momentum ${\bf Q}$ (the $\pi $channel) contributes little to
the resonance. However, if the interband density-density interaction is
attractive and the $\pi-$resonance is possible on its own, along with the
spin-exciton, we find a much stronger shift of the resonance frequency from the
position of the would-be spin-exciton resonance. We also show that the expected
double-peak structure in this situation does not appear because of the strong
coupling between particle-hole and particle-particle channels, and $\mathrm{Im}
\chi_S ({\bf Q}, \omega)$ displays only a single peak.",1408.0021v1
2023-11-28,The structure of the wave operators in four dimensions in the presence of resonances,"We show that the wave operators for Schr\""{o}dinger scattering in
$\mathbb{R}^4$ have a particular form which depends on the existence of
resonances. As a consequence of this form, we determine the contribution of
resonances to the index of the wave operator.",2311.16438v1
2019-06-05,Storing quantum information in spins and high-sensitivity ESR,"Quantum information, encoded within the states of quantum systems, represents
a novel and rich form of information which has inspired new types of computers
and communications systems. Many diverse electron spin systems have been
studied with a view to storing quantum information, including molecular
radicals, point defects and impurities in inorganic systems, and quantum dots
in semiconductor devices. In these systems, spin coherence times can exceed
seconds, single spins can be addressed through electrical and optical methods,
and new spin systems with advantageous properties continue to be identified.
Spin ensembles strongly coupled to microwave resonators can, in principle, be
used to store the coherent states of single microwave photons, enabling
so-called microwave quantum memories. We discuss key requirements in realising
such memories, including considerations for superconducting resonators whose
frequency can be tuned onto resonance with the spins. Finally, progress towards
microwave quantum memories and other developments in the field of
superconducting quantum devices are being used to push the limits of
sensitivity of inductively-detected electron spin resonance. The
state-of-the-art currently stands at around 65 spins per root-Hz, with
prospects to scale down to even fewer spins.",1906.02092v1
2013-08-01,Transition from resonances to surface waves in pi^+-p elastic scattering,"In this article we study resonances and surface waves in $\pi^+$--p
scattering. We focus on the sequence whose spin-parity values are given by $J^p
= {3/2}^+,{7/2}^+, {11/2}^+, {15/2}^+,{19/2}^+$. A widely-held belief takes for
granted that this sequence can be connected by a moving pole in the complex
angular momentum (CAM) plane, which gives rise to a linear trajectory of the
form $J = \alpha_0+\alpha' m^2$, $\alpha'\sim 1/(\mathrm{GeV})^2$, which is the
standard expression of the Regge pole trajectory. But the phenomenology shows
that only the first few resonances lie on a trajectory of this type. For higher
$J^p$ this rule is violated and is substituted by the relation $J\sim kR$,
where $k$ is the pion--nucleon c.m.s.-momentum, and $R\sim 1$ fm. In this
article we prove: (a) Starting from a non-relativistic model of the proton,
regarded as composed by three quarks confined by harmonic potentials, we prove
that the first three members of this $\pi^+$-p resonance sequence can be
associated with a vibrational spectrum of the proton generated by an algebra
$Sp(3,R)$. Accordingly, these first three members of the sequence can be
described by Regge poles and lie on a standard linear trajectory. (b) At higher
energies the amplitudes are dominated by diffractive scattering, and the
creeping waves play a dominant role. They can be described by a second class of
poles, which can be called Sommerfeld's poles, and lie on a line nearly
parallel to the imaginary axis of the CAM-plane. (c) The Sommerfeld pole which
is closest to the real axis of the CAM-plane is dominant at large angles, and
describes in a proper way the backward diffractive peak in both the following
cases: at fixed $k$, as a function of the scattering angle, and at fixed
scattering angle $\theta=\pi$, as a function of $k$. (d) The evolution of this
pole, as a function of $k$, is given in first approximation by $J\simeq kR$.",1308.0222v1
2018-08-25,Resonance spin transfer torque in ferromagnetic/normal/ferromagnetic spin-valve structure of topological insulators,"We theoretically study the spin current and spin-transfer torque generation
in a conventional spin- valve hybrid structure of type ferromagnetic/normal
metal/ferromagnetic (FM/NM/FM) made of the topological insulator (TI), in which
a gate voltage is attached to the normal layer. We demonstrate the penetration
of the spin-transfer torque into the right ferromagnetic layer and show that,
unlike graphene spin-valve junction, the spin-transfer torque in TI is very
sensitive to the chemical potential of the NM region. As an important result,
by changing the chemical potential of the NM spacer and magnetization
directions, one can control all components of the STT. Interestingly, both the
resonance spin current and the resonance spin-transfer torque appear for
energies determined from a resonance equation. By increasing the chemical
potential of the NM spacer, the amplitude of the STTs decreases while at large
chemical potentials of $\mu_N$ there are intervals of chemical potential in
which both the spin current and the spin-transfer torque become zero. These
findings could open new perspectives for applications in spin-transfer torque
magnetic random access memory (STT-MRAM) devices based on TI.",1808.08379v1
1992-11-10,Spin-Wave Theory of the Spiral Phase of the t-J Model,"A graded H.P,realization of the SU(2|1) algebra is proposed.A spin-wave
theory with a condition that the sublattice magnetization is zero is
discussed.The long-range spiral phase is investigated.The spin-spin correlator
is calculated.",9211005v1
2020-08-26,Theory of three-magnon interaction in a vortex-state magnetic nanodot,"We use vector Hamiltonian formalism (VHF) to study theoretically three-magnon
parametric interaction (or three-wave splitting) in a magnetic disk existing in
a magnetic vortex ground state. The three-wave splitting in a disk is found to
obey two selection rules: (i) conservation of the total azimuthal number of the
resultant spin-wave modes, and (ii) inequality for the radial numbers of
interacting modes, if the mode directly excited by the driving field is
radially symmetric (i.e. if the azimuthal number of the directly excited mode
is $m = 0$). The selection rule (ii), however, is relaxed in the ""small""
magnetic disks, due to the influence of the vortex core. We also found, that
the efficiency of the three-wave interaction of the directly excited mode
strongly depends on the azimuthal and radial mode numbers of the resultant
modes, that becomes determinative in the case when several splitting channels
(several pairs of resultant modes) simultaneously approximately satisfy the
resonance condition for the splitting. The good agreement of the VHF analytic
calculations with the experiment and micromagnetic simulations proves the
capability of the VHF formalism to predict the actual splitting channels and
the magnitudes of the driving field thresholds for the three-wave splitting.",2008.11812v2
2013-11-12,Quantum theory of spin waves in finite chiral spin chains,"We calculate the effect of spin waves on the properties of finite size spin
chains with a chiral spin ground state observed on bi-atomic Fe chains
deposited on Iridium(001). The system is described with a Heisenberg model
supplemented with a Dzyaloshinskii-Moriya (DM) coupling and a uniaxial single
ion anisotropy that presents a chiral spin ground state. Spin waves are studied
using the Holstein-Primakoff (HP) boson representation of spin operators. Both
the renormalized ground state and the elementary excitations are found by means
of Bogoliubov transformation, as a function of the two variables that can be
controlled experimentally, the applied magnetic field and the chain length.
Three main results are found. First, because of the non-collinear nature of the
classical ground state, there is a significant zero point reduction of the
ground state magnetization of the spin spiral. Second, the two lowest energy
spin waves are edge modes in the spin spiral state that, above a critical field
the results into a collinear ferromagnetic ground state, become confined bulk
modes. Third, in the spin spiral state, the spin wave spectrum exhibits
oscillatory behavior as function of the chain length with the same period of
the spin helix.",1311.2695v1
2020-05-04,Spin-orbit-torque magnonics,"The field of magnonics, which utilizes propagating spin waves for nano-scale
transmission and processing of information, has been significantly advanced by
the advent of the spin-orbit torque. The latter phenomenon can allow one to
overcome two main drawbacks of magnonic devices - low energy efficiency of
conversion of electrical signals into spin wave signals, and fast spatial decay
of spin waves in thin-film waveguiding structures. At first glance, the
excitation and amplification of spin waves by spin-orbit torques can seem to be
straightforward. Recent research indicates, however, that the lack of the
mode-selectivity in the interaction of spin currents with dynamic magnetic
modes and the onset of dynamic nonlinear phenomena represent significant
obstacles. Here, we discuss the possible route to overcoming these limitations,
based on the suppression of nonlinear spin-wave interactions in magnetic
systems with perpendicular magnetic anisotropy. We show that this approach
enables efficient excitation of coherent magnetization dynamics and propagating
spin waves in extended spatial regions, and is expected to enable practical
implementation of complete compensation of spin-wave propagation losses.",2005.01391v1
2007-10-03,Nuclear Tuning and Detuning of the Electron Spin Resonance in a Quantum Dot,"We study nuclear spin dynamics in a quantum dot close to the conditions of
electron spin resonance. We show that at small frequency mismatch the nuclear
field detunes the resonance. Remarkably, at larger frequency mismatch its
effect is opposite: The nuclear system is bistable, and in one of the stable
states the field accurately tunes the electron spin splitting to resonance. In
this state the nuclear field fluctuations are strongly suppressed and nuclear
spin relaxation is accelerated.",0710.0750v2
2008-04-07,Resonant Spin Polarization and Hall Effects in a Two-Dimensional Electron Gas,"We have studied transport properties in a two-dimensional electron gas with
equal Rashba and Dresselhaus spin-orbit interactions under a perpendicular
magnetic field. By employing the exact solution for this system, we found
resonant charge and spin Hall conductances at a certain magnetic field, where
all the nearest-neighboring Landau levels cross. Near this value of magnetic
field, there exists a resonant spin polarization, which can also induce
resonant charge and spin Hall effects.",0804.1138v1
2012-07-02,Spin-dependent Fano resonance induced by conducting chiral helimagnet contained in a quasi-one-dimensional electron waveguide,"Fano resonance appears for conduction through an electron waveguide
containing donor impurities. In this work, we consider the thin-film conducting
chiral helimagnet (CCH) as the donor impurity in a one-dimensional waveguide
model. Due to the spin spiral coupling, interference between the direct and
intersubband transmission channels gives rise to spin-dependent Fano resonance
effect. The spin-dependent Fano resonance is sensitively dependent on the
helicity of the spiral. By tuning the CCH potential well depth and the incident
energy, this provides a potential way to detect the spin structure in the CCH.",1207.0490v2
2012-12-12,Anisotropic rare-earth spin ensemble strongly coupled to a superconducting resonator,"Interfacing photonic and solid-state qubits within a hybrid quantum
architecture offers a promising route towards large scale distributed quantum
computing. Ideal candidates for coherent qubit interconversion are optically
active spins magnetically coupled to a superconducting resonator. We report on
a cavity QED experiment with magnetically anisotropic Er3+:Y2SiO5 crystals and
demonstrate strong coupling of rare-earth spins to a lumped element resonator.
In addition, the electron spin resonance and relaxation dynamics of the erbium
spins are detected via direct microwave absorption, without aid of a cavity.",1212.2856v1
2019-03-17,Sensing Kondo correlations in a suspended carbon nanotube mechanical resonator with spin-orbit coupling,"We study electron mechanical coupling in a suspended carbon nanotube (CNT)
quantum dot device. Electron spin couples to the flexural vibration mode due to
spin-orbit coupling in the electron tunneling processes. In the weak coupling
limit, i.e. electron-vibration coupling is much smaller than the electron
energy scale, the damping and resonant frequency shift of the CNT resonator can
be obtained by calculating the dynamical spin susceptibility. We find that
strong spin-flip scattering processes in Kondo regime significantly affect the
mechanical motion of the carbon nanotube: Kondo effect induces strong damping
and frequency shift of the CNT resonator.",1903.07049v1
2022-06-25,High cooperativity coupling of rare earth spins with planar superconducting resonator,"Interfacing superconducting microwave resonator with rare earth doped
crystals presents a promising hybrid quantum system for applications including
spin-assisted transducers and memories. The coupling strength between spins of
rare earth ions and the microwave photons is characterized by the
cooperativity. Here we report an ultra-high cooperativity $C \sim$ 650 between
rare earth spins and a planar superconducting microwave resonator that features
a highly uniform magnetic field for harnessing the strong anisotropic coupling
strength of erbium doped yttrium orthosilicate. This cooperativity rivals that
from a bulk dielectric resonator and paves a path for efficiently coupling of
spins with microwave photons on an integrated platform.",2206.12646v1
2012-01-24,Electron Spin Resonance of the Yb 4f moment in Yb(Rh1-xCox)2Si2,"[published in Phys. Rev. B 85, 035119 (2012)] The evolution of spin dynamics
from the quantum critical system YbRh2Si2 to the stable trivalent Yb system
YbCo2Si2 was investigated by Electron Spin Resonance (ESR) spectroscopy. While
the Kondo temperature changes by one order of magnitude, all compositions of
the single crystalline series Yb(Rh1-xCox)2Si2 show well defined ESR spectra
with a clear Yb3+ character for temperatures below \approx 20 K. With
increasing Co-content the ESR g-factor along the c-direction strongly increases
indicating a continuous change of the ground state wave function and, thus, a
continuous change of the crystal electric field. The linewidth presents a
complex dependence on the Co-content and is discussed in terms of the Co-doping
dependence of the Kondo interaction, the magnetic anisotropy and the influence
of ferromagnetic correlations between the 4f states. The results provide
evidence that, for low Co-doping, the Kondo interaction allows narrow ESR
spectra despite the presence of a large magnetic anisotropy, whereas at high
Co-concentrations, the linewidth is controlled by ferromagnetic correlations. A
pronounced broadening due to critical correlations at low temperatures is only
observed at the highest Co-content. This might be related to the presence of
incommensurate magnetic fluctuations.",1201.5022v1
2016-10-06,Charge fluctuations and nodeless superconductivity in quasi-one-dimensional Ta$_{4}$Pd$_{3}$Te$_{16}$ revealed by $^{125}$Te-NMR and $^{181}$Ta-NQR,"We report $^{125}$Te nuclear magnetic resonance and $^{181}$Ta nuclear
quadrupole resonance studies on single-crystal Ta$_{4}$Pd$_{3}$Te$_{16}$, which
has a quasi-one-dimensional structure and superconducts below $T_{\rm c}=4.3$
K. $^{181}$Ta with spin $I=7/2$ is sensitive to quadrupole interactions, while
$^{125}$Te with spin $I=1/2$ can only relax by magnetic interactions. By
comparing the spin-lattice relaxation rate ( $1/T_{1}$) of $^{181}$Ta and
$^{125}$Te, we found that electric-field-gradient (EFG) fluctuations develop
below $80$ K. The EFG fluctuations are enhanced with decreasing temperature due
to the fluctuations of a charge density wave that sets in at $T_{\rm CDW}=20$
K, below which the spectra are broadened and $1/T_{1}T$ drops sharply. In the
superconducting state, $1/T_{1}$ shows a Hebel-Slichter coherence peak just
below $T_{\rm c}$ for $^{125}$Te, indicating that Ta$_{4}$Pd$_{3}$Te$_{16}$ is
a full-gap superconductor without nodes in the gap function. The coherence peak
is absent in the $1/T_{1}$ of $^{181}$Ta due to the strong EFG fluctuations.",1610.01811v2
2017-09-11,"Electronic and magnetic excitations in the ""half-stuffed"" Cu--O planes of Ba$_2$Cu$_3$O$_4$Cl$_2$ measured by resonant inelastic x-ray scattering","We use resonant inelastic x-ray scattering (RIXS) at the Cu L$_3$ edge to
measure the charge and spin excitations in the ""half-stuffed"" Cu--O planes of
the cuprate antiferromagnet Ba$_2$Cu$_3$O$_4$Cl$_2$. The RIXS line shape
reveals distinct contributions to the $dd$ excitations from the two
structurally inequivalent Cu sites, which have different out-of-plane
coordinations. The low-energy response exhibits magnetic excitations. We find a
spin-wave branch whose dispersion follows the symmetry of a CuO$_2$ sublattice,
similar to the case of the ""fully-stuffed"" planes of tetragonal CuO (T-CuO).
Its bandwidth is closer to that of a typical cuprate material, such as
Sr$_2$CuO$_2$Cl$_2$, than it is to that of T-CuO. We interpret this result as
arising from the absence of the effective four-spin inter-sublattice
interactions that act to reduce the bandwidth in T-CuO.",1709.03427v1
2014-02-15,Measurement of the intrinsic damping constant in individual nanodisks of YIG and YIG{\textbar}Pt,"We report on an experimental study on the spin-waves relaxation rate in two
series of nanodisks of diameter $\phi=$300, 500 and 700~nm, patterned out of
two systems: a 20~nm thick yttrium iron garnet (YIG) film grown by pulsed laser
deposition either bare or covered by 13~nm of Pt. Using a magnetic resonance
force microscope, we measure precisely the ferromagnetic resonance linewidth of
each individual YIG and YIG{\textbar}Pt nanodisks. We find that the linewidth
in the nanostructure is sensibly smaller than the one measured in the extended
film. Analysis of the frequency dependence of the spectral linewidth indicates
that the improvement is principally due to the suppression of the inhomogeneous
part of the broadening due to geometrical confinement, suggesting that only the
homogeneous broadening contributes to the linewidth of the nanostructure. For
the bare YIG nano-disks, the broadening is associated to a damping constant
$\alpha = 4 \cdot 10^{-4}$. A 3 fold increase of the linewidth is observed for
the series with Pt cap layer, attributed to the spin pumping effect. The
measured enhancement allows to extract the spin mixing conductance found to be
$G_{\uparrow \downarrow}= 1.55 \cdot 10^{14}~ \Omega^{-1}\text{m}^{-2}$ for our
YIG(20nm){\textbar}Pt interface, thus opening large opportunities for the
design of YIG based nanostructures with optimized magnetic losses.",1402.3630v1
2014-05-19,"Comparison of micromagnetic parameters of ferromagnetic semiconductors (Ga,Mn)(As,P) and (Ga,Mn)As","We report on the determination of micromagnetic parameters of epilayers of
the ferromagnetic semiconductor (Ga,Mn)As, which has easy axis in the sample
plane, and (Ga,Mn)(As,P) which has easy axis perpendicular to the sample plane.
We use an optical analog of ferromagnetic resonance where the
laser-pulse-induced precession of magnetization is measured directly in the
time domain. By the analysis of a single set of pump-and-probe magneto-optical
data we determined the magnetic anisotropy fields, the spin stiffness and the
Gilbert damping constant in these two materials. We show that incorporation of
10% of phosphorus in (Ga,Mn)As with 6% of manganese leads not only to the
expected sign change of the perpendicular to plane anisotropy field but also to
an increase of the Gilbert damping and to a reduction of the spin stiffness.
The observed changes in the micromagnetic parameters upon incorporating P in
(Ga,Mn)As are consistent with the reduced hole density, conductivity, and Curie
temperature of the (Ga,Mn)(As,P) material. We report that the magnetization
precession damping is stronger for the n = 1 spin wave resonance mode than for
the n = 0 uniform magnetization precession mode.",1405.4677v1
2018-06-29,Restricted basis set coupled-channel calculations on atom-molecule collisions in magnetic fields,"Rigorous coupled-channel quantum scattering calculations on molecular
collisions in external fields are computationally demanding due to the need to
account for a large number of coupled channels and multiple total angular
momenta $J$ of the collision complex. We show that by restricting the number of
total angular momentum basis states to include only the states with helicities
$K\le K_\text{max}$ it is possible to obtain accurate elastic and inelastic
cross sections for He+CaH, Li+CaH and Li+SrOH collisions at a small fraction of
the computational cost of the full coupled-channel calculations (where $K$ is
the projection of the molecular rotational angular momentum on the atom-diatom
axis). The optimal size of the truncated helicity basis set depends on the
mechanism of the inelastic process and on the magnitude of the external
magnetic field. For dipolar-mediated spin relaxation in ultracold Li+CaH and
Li+SrOH collisions, we find that a minimal helicity basis set
($K_\text{max}=0$) gives quantitatively accurate results at ultralow collision
energies, leading to nearly 90-fold gain in computational efficiency. Larger
basis sets are required to accurately describe the resonance structure in
Li+CaH and Li+SrOH inelastic cross sections in the few partial wave-regime
($K_\text{max}=3$) as well as indirect spin relaxation in He+CaH collisions
($K_\text{max}=1$). Our calculations indicate that the resonance structure is
due to an interplay of the spin-rotation and Coriolis couplings between the
basis states of different $K$ and the couplings between the rotational states
of the same $K$ induced by the anisotropy of the interaction potential.",1806.11312v1
2018-07-24,Ultrafast pulse phase shift in a charged quantum dot- micropillar system,"We employ a quantum master equations approach based on a vectorial
Maxwell-pseudospin model to compute the quantum evolution of the spin
populations and coherences in the fundamental singlet trion transition of a
negatively charged quantum dot embedded in a micropillar cavity. Excitation of
the system is achieved through an ultrashort, either circularly or linearly
polarised resonant pulse. By implementing a realistic micropillar cavity
geometry, we numerically demonstrate a giant optical phase shift ($\sim \pm
\pi/2$) of a resonant circularly polarised pulse in the weak-coupling regime.
The phase shift that we predict considerably exceeds the experimentally
observed Kerr rotation angle $(\sim{6 ^{\circ}})$ under a continuous-wave,
linearly polarised excitation. By contrast, we show that a linearly polarised
pulse is rotated to a much lesser extent of a few degrees. Depending on the
initial boundary conditions, this is due to either retardation or advancement
in the amplitude build-up in time of the orthogonal electric field component.
Unlike previous published work, the dominant spin relaxation and decoherence
processes are fully accounted for in the system dynamics. Our dynamical model
can be used for optimisation of the optical polarisation rotation angle for
realisation of spin-photon entanglement and ultrafast polarisation switching on
a chip.",1807.09176v1
2019-07-06,Analytical model for gravitational-wave echoes from spinning remnants,"Gravitational-wave echoes in the post-merger signal of a binary coalescence
are predicted in various scenarios, including near-horizon quantum structures,
exotic states of matter in ultracompact stars, and certain deviations from
general relativity. The amplitude and frequency of each echo is modulated by
the photon-sphere barrier of the remnant, which acts as a spin- and
frequency-dependent high-pass filter, decreasing the frequency content of each
subsequent echo. Furthermore, a major fraction of the energy of the echo signal
is contained in low-frequency resonances corresponding to the quasi-normal
modes of the remnant. Motivated by these features, in this work we provide an
analytical gravitational-wave template in the low-frequency approximation
describing the post-merger ringdown and the echo signal of a spinning
ultracompact object. Besides the standard ringdown parameters, the template is
parametrized in terms of only two physical quantities: the reflectivity
coefficient and the compactness of the remnant. We discuss novel effects
related to the spin and to the complex reflectivity, such as a more involved
modulation of subsequent echoes, the mixing of two polarizations, and the
ergoregion instability in case of perfectly-reflecting spinning remnants.
Finally, we compute the errors in the estimation of the template parameters
with current and future gravitational-wave detectors using a Fisher matrix
framework. Our analysis suggests that models with almost perfect reflectivity
can be excluded/detected with current instruments, whereas probing values of
the reflectivity smaller than $80\%$ at $3\sigma$ confidence level requires
future detectors (Einstein Telescope, Cosmic Explorer, LISA). The template
developed in this work can be easily implemented to perform a matched-filter
based search for echoes and to constrain models of exotic compact objects.",1907.03091v3
2014-08-09,Compton scattering in strong magnetic fields: Spin-dependent influences at the cyclotron resonance,"The quantum electrodynamical (QED) process of Compton scattering in strong
magnetic fields is commonly invoked in atmospheric and inner magnetospheric
models of x-ray and soft gamma-ray emission in high-field pulsars and
magnetars. A major influence of the field is to introduce resonances at the
cyclotron frequency and its harmonics, where the incoming photon accesses
thresholds for the creation of virtual electrons or positrons in intermediate
states with excited Landau levels. At these resonances, the effective cross
section typically exceeds the classical Thomson value by over 2 orders of
magnitude. Near and above the quantum critical magnetic field of 44.13
TeraGauss, relativistic corrections must be incorporated when computing this
cross section. This paper presents formalism for the QED magnetic Compton
differential cross section valid for both subcritical and supercritical fields,
yet restricted to scattered photons that are below pair creation threshold.
Calculations are developed for the particular case of photons initially
propagating along the field, mathematically simple specializations that are
germane to interactions involving relativistic electrons frequently found in
neutron star magnetospheres. This exposition of relativistic, quantum, magnetic
Compton cross sections treats electron spin dependence fully, since this is a
critical feature for describing the finite decay lifetimes of the intermediate
states. The formalism employs both the Johnson and Lippmann (JL) wave functions
and the Sokolov and Ternov (ST) electron eigenfunctions of the magnetic Dirac
equation. The ST states are formally correct for self-consistently treating
spin-dependent effects that are so important in the resonances. Relatively
compact analytic forms for the cross sections are presented that will prove
useful for astrophysical modelers.",1408.2146v1
2018-11-01,Excited states of $^{39}$Ca and their significance in nova nucleosynthesis,"Background: Discrepancies exist between the observed abundances of argon and
calcium in oxygen-neon nova ejecta and those predicted by nova models. An
improved characterization of the $^{38}$K($p, \gamma$)$^{39}$Ca reaction rate
over the nova temperature regime ($\sim$ 0.1 -- 0.4 GK), and thus the nuclear
structure of $^{39}$Ca above the proton threshold (5770.92(63) keV), is
necessary to resolve these contradictions.
  Purpose: The present study was performed to search for low-spin proton
resonances in the $^{38}$K $+$ $p$ system, and to improve the uncertainties in
energies of the known astrophysically significant proton resonances in
$^{39}$Ca.
  Method: The level structure of $^{39}$Ca was investigated via high-resolution
charged-particle spectroscopy with an Enge split-pole spectrograph using the
$^{40}$Ca($^{3}$He, $\alpha$)$^{39}$Ca reaction. Differential cross sections
were measured over 6 laboratory angles at 21 MeV. Distorted-wave Born
approximation calculations were performed to constrain the spin-parity
assignments of observed levels with special attention to those significant in
determination of the $^{38}$K($p, \gamma$)$^{39}$Ca reaction rate over the nova
temperature regime.
  Results: The resonance energies corresponding to two out of three
astrophysically important states at 6154(5) and 6472.2(24) keV are measured
with better precision than previous charged-particle spectroscopy measurements.
A tentatively new state is discovered at 5908(3) keV. The spin-parity
assignments of a few of the astrophysically important resonances are
determined.
  Conclusions: The present $^{38}$K($p, \gamma$)$^{39}$Ca upper limit
thermonuclear reaction rate at 0.1 -- 0.4 GK is higher than that determined in
[Physical Review C 97 (2018) 025802] by at most a factor of 1.4 at 0.1 GK.",1811.00398v1
1993-01-13,"Hierarchical wave function, Fock cyclic condition and spin-statistics relation in the spin-singlet fractional quantum Hall effect","We construct the hierarchical wave function of the spin-singlet fractional
quantum Hall effect, which turns out to satisfy Fock cyclic condition. The
spin-statistics relation of the quasi-particles in the spin-singlet fractional
quantum Hall effect is also discussed. Then we use particle-hole conjugation to
check the wave function.",9301015v1
2018-10-22,Excitation and resonant enhancement of axisymmetric internal wave modes,"To date, axisymmetric internal wave fields, which have relevance to
atmospheric internal wave fields generated by storm cells and oceanic
near-inertial wave fields generated by surface storms, have been experimentally
realized using an oscillating sphere or torus as the source. Here, we use a
novel wave generator configuration capable of exciting axisymmetric internal
wave fields of arbitrary radial form to generate axisymmetric internal wave
modes. After establishing the theoretical background for axisymmetric mode
propagation, taking into account lateral and vertical confinement, and also
accounting for the effects of weak viscosity, we experimentally generate and
study modes of different order. We characterize the efficiency of the wave
generator through careful measurement of the wave amplitude based upon group
velocity arguments. This established, we investigate the ability of vertical
confinement to induce resonance, identifying a series of experimental resonant
peaks that agree well with theoretical predictions. In the vicinity of
resonance, the wave fields undergo a transition to non-linear behaviour that is
initiated on the central axis of the domain and proceeds to erode the wave
field throughout the domain.",1810.09151v1
2016-03-08,Experimental study of three-wave interactions among capillary-gravity surface waves,"In propagating wave systems, three or four-wave resonant interactions
constitute a classical non-linear mechanism exchanging energy between the
different scales. Here we investigate three-wave interactions for
gravity-capillary surface waves in a closed laboratory tank. We generate two
crossing wave-trains and we study their interaction. Using two optical methods,
a local one (Laser Doppler Vibrometry) and a spatio-temporal one (Diffusive
Light Photography), a third wave of smaller amplitude is detected, verifying
the three-wave resonance conditions in frequency and in wavenumber.
Furthermore, by focusing on the stationary regime and by taking into account
viscous dissipation, we directly estimate the growth rate of the resonant mode.
The latter is then compared to the predictions of the weakly non-linear triadic
resonance interaction theory. The obtained results confirm qualitatively and
extend previous experimental results obtained only for collinear wave-trains.
Finally, we discuss the relevance of three-wave interaction mechanisms in
recent experiments studying gravity-capillary turbulence.",1603.02654v1
2015-05-15,High-energy magnetic excitations in overdoped La$_{2-x}$Sr$_{x}$CuO$_{4}$ studied by neutron and resonant inelastic X-ray scattering,"We have performed neutron inelastic scattering and resonant inelastic X-ray
scattering (RIXS) at the Cu-$L_3$ edge to study high-energy magnetic
excitations at energy transfers of more than 100 meV for overdoped
La$_{2-x}$Sr$_{x}$CuO$_{4}$ with $x=0.25$ ($T_c=15$ K) and $x=0.30$
(non-superconducting) using identical single crystal samples for the two
techniques. From constant-energy slices of neutron scattering cross-sections,
we have identified magnetic excitations up to ~250 meV for $x=0.25$. Although
the width in the momentum direction is large, the peak positions along the (pi,
pi) direction agree with the dispersion relation of the spin-wave in the
non-doped La$_{2}$CuO$_{4}$ (LCO), which is consistent with the previous RIXS
results of cuprate superconductors. Using RIXS at the Cu-$L_3$ edge, we have
measured the dispersion relations of the so-called paramagnon mode along both
(pi, pi) and (pi, 0) directions. Although in both directions the neutron and
RIXS data connect with each other and the paramagnon along (pi, 0) agrees well
with the LCO spin-wave dispersion, the paramagnon in the (pi, pi) direction
probed by RIXS appears to be less dispersive and the excitation energy is lower
than the spin-wave of LCO near (pi/2, pi/2). Thus, our results indicate
consistency between neutron inelastic scattering and RIXS, and elucidate the
entire magnetic excitation in the (pi, pi) direction by the complementary use
of two probes. The polarization dependence of the RIXS profiles indicates that
appreciable charge excitations exist in the same energy range of magnetic
excitations, reflecting the itinerant character of the overdoped sample. A
possible anisotropy in the charge excitation intensity might explain the
apparent differences in the paramagnon dispersion in the (pi, pi) direction as
detected by the X-ray scattering.",1505.03945v1
2021-08-24,Full-Spin-Wave-Scaled Finite Element Stochastic Micromagnetism: Mesh-Independent FUSSS LLG Simulations of Ferromagnetic Resonance and Reversal,"In this paper, we address the problem that standard stochastic
Landau-Lifshitz-Gilbert (sLLG) simulations typically produce results that show
unphysical mesh-size dependence. The root cause of this problem is that the
effects of spin wave fluctuations are ignored in sLLG. We propose to represent
the effect of these fluctuations by a ""FUll-Spinwave-Scaled Stochastic LLG"", or
FUSSS LLG method. In FUSSS LLG, the intrinsic parameters of the sLLG
simulations are first scaled by scaling factors that integrate out the spin
wave fluctuations up to the mesh size, and the sLLG simulation is then
performed with these scaled parameters. We developed FUSSS LLG by studying the
Ferromagnetic Resonance (FMR) in Nd$_2$Fe$_{14}$B cubes. The nominal scaling
greatly reduced the mesh size dependence relative to sLLG. We further
discovered that adjusting one scaling exponent by less than 10% delivered fully
mesh-size-independent results for the FMR peak. We then performed three tests
and validations of our FUSSS LLG with this modified scaling. 1) We studied the
same FMR but with magnetostatic fields included. 2) We simulated the total
magnetization of the Nd$_2$Fe$_{14}$B cube. 3) We studied the effective,
temperature- and sweeping rate-dependent coercive field of the cubes. In all
three cases we found that FUSSS LLG delivered essentially mesh-size-independent
results, which tracked the theoretical expectations better than unscaled sLLG.
Motivated by these successful validations, we propose that FUSSS LLG provides
marked, qualitative progress towards accurate, high precision modeling of
micromagnetics in hard, permanent magnets.",2108.10582v1
2009-07-16,Reverse Doppler effect in backward spin waves scattered on acoustic waves,"We report on the observation of reverse Doppler effect in backward spin waves
reflected off of surface acoustic waves. The spin waves are excited in a
yttrium iron garnet (YIG) film. Simultaneously, acoustic waves are also
generated. The strain induced by the acoustic waves in the magnetostrictive YIG
film results in the periodic modulation of the magnetic anisotropy in the film.
Thus, in effect, a travelling Bragg grating for the spin waves is produced. The
backward spin waves reflecting off of this grating exhibit a reverse Doppler
shift: shifting down rather than up in frequency when reflecting off of an
approaching acoustic wave. Similarly, the spin waves are shifted up in
frequency when reflecting from receding acoustic waves.",0907.2902v1
2021-07-28,On a transitional regime of electron resonant interaction with whistler-mode waves in inhomogeneous space plasma,"Resonances with electromagnetic whistler-mode waves are the primary driver
for the formation and dynamics of energetic electron fluxes in various space
plasma systems, including shock waves and planetary radiation belts. The basic
and most elaborated theoretical framework for the description of the integral
effect of multiple resonant interactions is the quasi-linear theory, that
operates through electron diffusion in velocity space. The quasi-linear
diffusion rate scales linearly with the wave intensity, D(QL) is proportional
to Bw2, which should be small enough to satisfy the applicability criteria of
this theory. Spacecraft measurements, however, often detect whistle-mode waves
sufficiently intense to resonate with electrons nonlinearly. Such nonlinear
resonant interactions imply effects of phase trapping and phase bunching, which
may quickly change the electron fluxes in a non-diffusive manner. Both regimes
of electron resonant interactions (diffusive and nonlinear) are well studied,
but there is no theory quantifying the transition between these two regimes. In
this paper we describe the integral effect of nonlinear electron interactions
with whistler-mode waves in terms of the time-scale of electron distribution
relaxation, is about inverse D(NL). We determine the scaling of D(NL) with wave
intensity Bw2 and other main wave characteristics, such as wave-packet size.
The comparison of D(QL) and D(NL) provides the range of wave intensity and
wave-packet sizes where the electron distribution evolves at the same rates for
the diffusive and nonlinear resonant regimes. The obtained results are
discussed in the context of energetic electron dynamics in the Earth's
radiation belt.",2107.13511v1
2006-05-25,Fast Computation Algorithm for Discrete Resonances among Gravity Waves,"Traditionally resonant interactions among short waves, with large real
wave-numbers, were described statistically and only a small domain in spectral
space with integer wave-numbers, discrete resonances, had to be studied
separately in resonators. Numerical simulations of the last few years showed
unambiguously the existence of some discrete effects in the short-waves part of
the wave spectrum. Newly presented model of laminated turbulence explains
theoretically appearance of these effects thus putting a novel problem -
construction of fast algorithms for computation of solutions of resonance
conditions with integer wave-numbers of order $10^3$ and more. Example of such
an algorithm for 4-waves interactions of gravity waves is given. Its
generalization on the different types of waves is briefly discussed.",0605067v1
2007-03-26,Interactions of renormalized waves in thermalized Fermi-Pasta-Ulam chains,"The dispersive interacting waves in Fermi-Pasta-Ulam (FPU) chains of
particles in \textit{thermal equilibrium} are studied from both statistical and
wave resonance perspectives. It is shown that, even in a strongly nonlinear
regime, the chain in thermal equilibrium can be effectively described by a
system of weakly interacting \textit{renormalized} nonlinear waves that possess
(i) the Rayleigh-Jeans distribution and (ii) zero correlations between waves,
just as noninteracting free waves would. This renormalization is achieved
through a set of canonical transformations. The renormalized linear dispersion
of these renormalized waves is obtained and shown to be in excellent agreement
with numerical experiments. Moreover, a dynamical interpretation of the
renormalization of the dispersion relation is provided via a self-consistency,
mean-field argument. It turns out that this renormalization arises mainly from
the trivial resonant wave interactions, i.e., interactions with no momentum
exchange. Furthermore, using a multiple time-scale, statistical averaging
method, we show that the interactions of near-resonant waves give rise to the
broadening of the resonance peaks in the frequency spectrum of renormalized
modes. The theoretical prediction for the resonance width for the thermalized
$\beta$-FPU chain is found to be in very good agreement with its numerically
measured value.",0703051v1
2008-09-01,Spin Fluctuation Dynamics and Multiband Superconductivity in Iron Pnictides,"Multiband superconductivity, involving resonant pair scattering between
different bands, has emerged as a possible explanation of some of the main
characteristics of the recently discovered iron pnictides. A key feature of
such interband pairing mechanism is that it can generate or enhance
superconducting pairing irrespective of whether it is attractive or repulsive.
The latter case typically leads to the superconducting gap switching its sign
among different sections of the Fermi surface. In iron pnictides, the natural
scenario is that the gap changes sign between the hole and the electron Fermi
surfaces. However, the macroscopic symmetry of such an extended s'-wave state
still belongs to the general s-wave category, raising the question of how to
distinguish it from an ordinary s-wave. In such a quest, it is essential to use
experimental techniques that have a momentum space resolution and can probe
momenta of order M, the wavevector that separates the hole and the electron
Fermi surfaces in the Brillouin zone. Here we study experimental signatures in
the spin fluctuation dynamics of the fully-gapped s- and s'-wave
superconducting states, as well as those of the nodal d- and p-wave. The
coupling between spin fluctuations of the incipient nearly-nested spin
density-wave (SDW) and the Bogoliubov-deGennes quasiparticles of the
superconducting state leads to the Landau-type damping of the former. The
intrinsic structure of the superconducting gap leaves a distinctive signature
in the form of this damping, allowing it to be used to diagnose the nature of
iron-based superconductivity in neutron scattering and other experiments
sensitive to spin fluctuations in momentum space. We also discuss the
coexistence between superconductivity and SDW order.",0809.0014v1
2014-07-03,Hyperfine coupling and spin polarization in the bulk of the topological insulator Bi$_2$Se$_3$,"Nuclear magnetic resonance (NMR) and transport measurements have been
performed at high magnetic fields and low temperatures in a series of $n$-type
Bi$_{2}$Se$_{3}$ crystals. In low density samples, a complete spin polarization
of the electronic system is achieved, as observed from the saturation of the
isotropic component of the $^{209}$Bi NMR shift above a certain magnetic field.
The corresponding spin splitting, defined in the phenomenological approach of a
3D electron gas with a large (spin-orbit-induced) effective $g$-factor, scales
as expected with the Fermi energy independently determined by simultaneous
transport measurements. Both the effective electronic $g$-factor and the
""contact"" hyperfine coupling constant are precisely determined. The magnitude
of this latter reveals a non negligible $s$-character of the electronic wave
function at the bottom of the conduction band. Our results show that the bulk
electronic spin polarization can be directly probed via NMR and pave the way
for future NMR investigations of the electronic states in Bi-based topological
insulators.",1407.1040v2
2015-03-20,Magnetic excitations of perovskite rare-earth nickelates: RNiO$_3$,"The perovskite nickelates RNiO$_3$ (R: rare-earth) have been studied as
potential multiferroic compounds. A certain degree of charge disproportionation
in the Ni ions has been confirmed by high resolution synchrotron power
diffraction: instead of the nominal Ni$^{3+}$ valence, they can have the
mixed-valence state Ni$^{(3-\delta)+}$ and Ni$^{(3+\delta)+}$, though agreement
has not been reached on the precise value of $\delta$ (e.g. for NdNiO$_3$,
$\delta=0.0$ and $\delta=0.29$ were reported). Also, the magnetic ground state
is not yet clear: collinear and non-collinear Ni-O magnetic structures have
been proposed to explain neutron diffraction and soft X-ray resonant
sccattering results in these compounds, and more recently a canted
antiferromagnetic spin arrangement was proposed on the basis of magnetic
susceptibility measurements. This scenario is reminiscent of the situation in
the half-doped manganites.
  In order to gain insight into the ground state of these compounds, we studied
the magnetic excitations of some of the different phases proposed, using a
localized spin model for a simplified spin chain which could describe these
compounds. We first analize the stability of the collinear, orthogonal, and
intermediate phases in the classical case. We then explore the quantum ground
state indirectly, calculating the spin excitations obtained for each phase,
using the Holstein-Primakoff transformation and the linear spin-wave
approximation. For the collinear and orthogonal ($\theta=\pi/2$) phases, we
predict differences in the magnon spectrum which would allow to distinguish
between them in future inelastic neutron scattering experiments.",1503.06102v1
2018-09-21,Tailored single-atom collisions at ultra-low energies,"We employ collisions of individual atomic cesium (Cs) impurities with an
ultracold rubidium (Rb) gas to probe atomic interaction with hyperfine- and
Zeeman-state sensitivity. Controlling the Rb bath's internal state yields
access to novel phenomena observed in inter-atomic spin-exchange. These can be
tailored at ultra-low energies, owing to the excellent experimental control
over all relevant energy scales. First, detecting spin-exchange dynamics in the
Cs hyperfine state manifold, we resolve a series of previously unreported
Feshbach resonances at magnetic fields below 300 mG, separated by energies as
low as $h\times 15$ kHz. The series originates from a coupling to molecular
states with binding energies below $h\times 1$ kHz and wave function extensions
in the micrometer range. Second, at magnetic fields below $\approx 100\,$mG, we
observe the emergence of a new reaction path for alkali atoms, where in a
single, direct collision between two atoms two quanta of angular momentum can
be transferred. This path originates from the hyperfine-analogue of dipolar
spin-spin relaxation. Our work yields control of subtle ultra-low-energy
features of atomic collision dynamics, opening new routes for advanced
state-to-state chemistry, for controlling spin-exchange in quantum many-body
systems for solid state simulations, or for determination of high-precision
molecular potentials.",1809.08165v2
2019-05-21,Anisotropic spin fluctuations in detwinned FeSe,"Superconductivity in FeSe emerges from a nematic phase that breaks four-fold
rotational symmetry in the iron plane. This phase may arise from orbital
ordering, spin fluctuations, or hidden magnetic quadrupolar order. Here we use
inelastic neutron scattering on a mosaic of single crystals of FeSe detwinned
by mounting on a BaFe2As2 substrate to demonstrate that spin excitations are
most intense at the antiferromagnetic wave vectors QAF = (1, 0) at low energies
E = 6-11 meV in the normal state. This two-fold (C2) anisotropy is reduced at
lower energies 3-5 meV, indicating a gapped four-fold (C4) mode. In the
superconducting state, however, the strong nematic anisotropy is again
reflected in the spin resonance (E = 3.7 meV) at QAF with incommensurate
scattering around 5-6 meV. Our results highlight the extreme electronic
anisotropy of the nematic phase of FeSe and are consistent with a highly
anisotropic superconducting gap driven by spin fluctuations.",1905.08399v1
2021-01-12,Excitation of resonant surface plasmons for evanescent waves refocusing by a superlens,"The amplification of evanescent waves by flat superlens requires a
near-resonance coupling which has been linked to resonant surface plasmons. A
subtle interplay has been proposed to exist between the excitation of
well-defined resonant surface plasmons and the focusing capability of a
superlens. To gain insights into these resonant modes and their contributions
to the amplification and recovery of evanescent waves, we performed simple but
robust full-wave FDTD simulations on causal negative index Lorentz models. We
found that well-defined pair of resonant surface plasmons is excited whenever a
coupling of a diverging transmitted beam and a converging refracted beam occurs
at the second interface. The resonant coupling of these modes at the interface
led to the excitation of a single interface resonance predicted by the theory.
The physical consequence of this resonance is that incident wave energy is
pumped into the negative-index material medium and beyond it. These phenomena
contribute substantially to the amplification and recovery of the near-fields
in the image plane. It is noteworthy that, for evanescent wave refocusing to be
achieved in a flat superlens, its thickness, and the source-to-superlens
distance should be optimized. This optimization is critical in that an optimal
thickness alongside optimal source-to-superlens distance will allow evanescent
wave refocusing to dominate material lost. The FDTD simulated result showed an
image of the point source inside the superlens and beyond it when its thickness
was optimized. The resolution of the image beyond the superlens was
$\sim.58\lambda$ and this superlens behaves like a near-perfect lens. Overall,
these numerically simulated results could serve as useful approximations to the
degree of resonant amplification and refocusing of near-fields that can be
achieved by flat superlens in near-fields experimental imaging setups.",2101.04625v1
2014-04-03,Theoretical study of a $d^{*}$ resonance in $^{3}G_{3}$ partial wave of nucleon-nucleon scattering,"Inspired by the recent results of the WASA-at-COSY Collaboration, in which
they found a resonance pole in the coupled $^{3}D_{3}$ - $^{3}G_{3}$ partial
waves as expected from the $d^{*}$ resonance hypothesis, we calculated the
resonance structure in the coupled $^{3}D_{3}$ - $^{3}G_{3}$ partial wave phase
shifts of nucleon-nucleon scattering in the framework of two constituent quark
models: the quark delocalization color screening model and the chiral quark
model. Our results show that there is a resonance $^{7}S_{3}^{\Delta\Delta}$ in
the coupled $^{3}D_{3}^{NN}$ and $^{3}G_{3}^{NN}$ partial waves in both of
these two models, which is in accordance with the expectation from the $d^{*}$
resonance structure. The resonance shape in the $^{3}D_{3}^{NN}$ partial wave
is remarkable, whereas in the $^{3}G_{3}^{NN}$ phase shifts there is a small
rise around the resonance energy. This result is in agreement with the recent
experimental observations of WASA-at-COSY Collaboration.",1404.0947v2
2016-08-15,Precession resonance in water waves,"We describe the theory and present numerical evidence for a new type of
nonlinear resonant interaction between gravity waves on the surface of deep
water. The resonance constitutes a generalisation of the usual 'exact'
resonance as we show that exchanges of energy between the waves can be enhanced
when the interaction is three-wave rather than four and the linear frequency
mismatch, or detuning, is non-zero i.e. $\omega_1\pm\omega_2\pm\omega_3 \neq0.$
This is possible because the resonance condition is now a match between the
so-called 'precession frequency' of a given $\textit{triad interaction}$ and an
existent nonlinear frequency in the system. In the limit of weak nonlinearity
this precession frequency is simply due to the linear 'drift' of the triad
phase; therefore, it tends toward the detuning. This means precession resonance
of this type can occur at finite amplitudes, with nonlinear corrections
contributing to the resonance. We report energy transfer efficiencies of up to
40%, depending on the model options. To the authors' knowledge this represents
the first new type of nonlinear resonance in surface gravity waves since the
seminal work of Benjamin & Feir (1967).",1608.04241v1
2018-07-05,Bridging magnonics and spin-orbitronics,"The emerging field of nano-magnonics utilizes high-frequency waves of
magnetization - the spin waves - for the transmission and processing of
information on the nanoscale. The advent of spin-transfer torque has spurred
significant advances in nano-magnonics, by enabling highly efficient local
spin-wave generation in magnonic nanodevices. Furthermore, the recent emergence
of spin-orbitronics, which utilizes spin-orbit interaction as the source of
spin torque, has provided a unique ability to exert spin torque over spatially
extended areas of magnonic structures, enabling enhanced spin-wave
transmission. Here, we experimentally demonstrate that these advances can be
efficiently combined. We utilize the same spin-orbit torque mechanism for the
generation of propagating spin waves, and for the long-range enhancement of
their propagation, in a single integrated nano-magnonic device. The
demonstrated system exhibits a controllable directional asymmetry of spin wave
emission, which is highly beneficial for applications in non-reciprocal
magnonic logic and neuromorphic computing.",1807.02050v1
2011-06-01,Resonant elastic soft x-ray scattering in oxygen-ordered YBa_2Cu_3O_{6+delta},"Static charge-density wave (CDW) and spin-density wave (SDW) order has been
convincingly observed in La-based cuprates for some time. However, more
recently it has been suggested by quantum oscillation, transport and
thermodynamic measurements that density wave order is generic to underdoped
cuprates and plays a significant role in YBa_2Cu_3O_{6+delta} (YBCO). We use
resonant soft x-ray scattering at the Cu L and O K edges to search for evidence
of density wave order in Ortho-II and Ortho-VIII oxygen-ordered YBCO. We report
a null result -- no evidence for static CDW order -- in both Ortho-II and
Ortho-VIII ordered YBCO. While this does not rule out static CDW order in the
CuO_2 planes of YBCO, these measurements place limits on the parameter space
(temperature, magnetic field, scattering vector) in which static CDW order may
exist. In addition, we present a detailed analysis of the energy and
polarization dependence of the Ortho-II superstructure Bragg reflection [0.5 0
0] at the Cu L edge. The intensity of this peak, which is due to the valence
modulations of Cu in the chain layer, is compared with calculations using
atomic scattering form factors deduced from x-ray absorption measurements. The
calculated energy and polarization dependence of the scattering intensity is
shown to agree very well with the measurement, validating the approach and
providing a framework for analyzing future resonant soft x-ray scattering
measurements.",1106.0311v1
2014-06-06,Resonant X-ray Scattering Study of Charge Density Wave Correlations in YBa$_2$Cu$_3$O$_{6+x}$,"We report the results a comprehensive study of charge density wave (CDW)
correlations in untwinned YBCO6+x single crystals with 0.4<x<0.99 using Cu-L3
edge resonant x-ray scattering (RXS). Evidence of CDW formation is found for
0.45<x<0.93, but not for samples with x<0.44 that exhibit incommensurate
spin-density-wave order, and in slightly overdoped samples with x=0.99. This
suggests the presence of two proximate zero-temperature CDW critical points at
doping pc1~0.08 and pc2~0.18. The CDW reflections are observed at
incommensurate in-plane wave vectors (d_a, 0) and (0, d_b). Both decrease
linearly with increasing doping, in agreement with recent reports on Bi-based
high-Tc superconductors, but in sharp contrast to the behavior of the 214
family. The CDW intensity and correlation length exhibit maxima at p~0.12,
coincident with a plateau in the superconducting transition temperature Tc. The
onset temperature of the CDW reflections depends non-monotonically on p, with a
maximum of~160 K for p~0.12. The RXS reflections exhibit a uniaxial intensity
anisotropy. We further observe a depression of CDW correlations upon cooling
below Tc, and (for samples with p> 0.09) an enhancement of the signal when an
external magnetic field up to 6 T is applied in the superconducting state. For
samples with p~0.08, where prior work has revealed a field-enhancement of
incommensurate magnetic order, the RXS signal is field-independent. This
supports a previously suggested scenario in which incommensurate charge and
spin orders compete against each other, in addition to individually competing
against. We discuss the relationship of these results to stripe order 214, the
pseudogap phenomenon, superconducting fluctuations, and quantum oscillations.",1406.1595v2
2016-10-20,Gd$^{3+}$ - Gd$^{3+}$ distances exceeding 3 nm determined by very high frequency continuous wave electron paramagnetic resonance,"Electron paramagnetic resonance spectroscopy in combination with
site-directed spin-labeling is a very powerful tool for elucidating the
structure and organization of biomolecules. Gd$^{3+}$ complexes have recently
emerged as a new class of spin labels for distance determination by pulsed EPR
spectroscopy at Q- and W-band. We present CW EPR measurements at 240 GHz (8.6
Tesla) on a series of Gd-rulers of the type Gd-PyMTA---spacer---Gd-PyMTA, with
Gd-Gd distances ranging from 1.2 nm to 4.3 nm. CW EPR measurements of these
Gd-rulers show that significant dipolar broadening of the central
$|-1/2\rangle\rightarrow|1/2\rangle$ transition occurs at 30 K for Gd-Gd
distances up to $\sim$ 3.4 nm with Gd-PyMTA as the spin label. This represents
a significant extension for distances accessible by CW EPR, as nitroxide-based
spin labels at X-band frequencies can typically only access distances up to
$\sim$ 2 nm. We show that this broadening persists at biologically relevant
temperatures above 200 K, and that this method is further extendable up to room
temperature by immobilizing the sample in glassy trehalose. We show that the
peak-to-peak broadening of the central transition follows the expected $~1/r^3$
dependence for the electron-electron dipolar interaction, from cryogenic
temperatures up to room temperature. A simple procedure for simulating the
dependence of the lineshape on interspin distance is presented, in which the
broadening of the central transition is modeled as an $S=1/2$ spin whose CW EPR
lineshape is broadened through electron-electron dipolar interactions with a
neighboring $S=7/2$ spin.",1610.06252v1
2020-09-29,Spin transfer torque in Mn$_3$Ga-based ferrimagnetic tunnel junctions from first principles,"We report on first-principles calculations of spin-transfer torque (STT) in
epitaxial magnetic tunnel junctions (MTJs) based on ferrimagnetic tetragonal
Mn$_3$Ga electrodes, both as analyzer in an Fe/MgO stack, and also in an
analogous stack with a second Mn$_3$Ga electrode (instead of Fe) as polarizer.
Solving the ballistic transport problem (NEGF + DFT) for the nonequilibrium
spin density in a scattering region extended to over 7.6 nm into the Mn$_3$Ga
electrode, we find long-range spatial oscillations of the STT decaying on a
length scale of a few tens of angstroms, both in the linear response regime and
for finite bias. The oscillatory behavior of the STT in Mn$_3$Ga is robust
against variations in the stack geometry and the applied bias voltage, which
may affect the phase and the amplitude of the spatial oscillation, but the wave
number is only responsive to variations in the longitudinal lattice constant of
Mn$_3$Ga (for fixed in-plane geometry) without being commensurate with the
lattice. Our interpretation of the long-range STT oscillations is based on the
bulk electronic structure of Mn$_3$Ga, taking also into account the
spin-filtering properties of the MgO barrier. Comparison to a fully
Mn$_3$Ga-based stack shows similar STT oscillations, but a significant
enhancement of both the TMR effect at the Fermi level and the STT at the
interface, due to resonant tunneling for the mirror-symmetric junction with
thinner barrier (three monoatomic layers). From the calculated energy
dependence of the spin-polarized transmissions at 0 V, we anticipate asymmetric
or symmetric TMR as a function of the applied bias voltage for the Fe-based and
the all-Mn$_3$Ga stacks, respectively, which also both exhibit a sign change
below 1 V. In the latter (symmetric) case we expect a TMR peak at zero, which
is larger for the thinner barriers because of a spin-polarized resonant
tunneling contribution.",2009.14095v2
2007-02-26,Two-component Analogue of Two-dimensional Long Wave-Short Wave Resonance Interaction Equations: A Derivation and Solutions,"The two-component analogue of two-dimensional long wave-short wave resonance
interaction equations is derived in a physical setting. Wronskian solutions of
the integrable two-component analogue of two-dimensional long wave-short wave
resonance interaction equations are presented.",0702051v2
2008-12-25,Note on the 2-component Analogue of 2-dimensional Long Wave-Short Wave Resonance Interaction System,"An integrable two-component analogue of the two-dimensional long wave-short
wave resonance interaction (2c-2d-LSRI) system is studied. Wronskian solutions
of 2c-2d-LSRI system are presented. A reduced case, which describes resonant
interaction between an interfacial wave and two surface wave packets in a two
layer fluid, is also discussed.",0812.4591v1
2015-03-13,Nonlocal resonances in weak turbulence of gravity-capillary waves,"We report a laboratory investigation of weak turbulence of water surface
waves in the gravity-capillary crossover. By using time-space resolved
profilometry and a bicoherence analysis, we observe that the nonlinear
processes involve 3-wave resonant interactions. By studying the solutions of
the resonance conditions we show that the nonlinear interaction is dominantly
1D and involves collinear wave vectors. Furthermore taking into account the
spectral widening due to weak nonlinearity explains that nonlocal interactions
are possible between a gravity wave and high frequency capillary ones. We
observe also that nonlinear 3-wave coupling is possible among gravity waves and
we raise the question of the relevance of this mechanism for oceanic waves.",1503.04110v1
2015-11-04,The instability of Wilton ripples,"Wilton ripples are a type of periodic traveling wave solution of the full
water wave problem incorporating the effects of surface tension. They are
characterized by a resonance phenomenon that alters the order at which the
resonant harmonic mode enters in a perturbation expansion. We compute such
solutions using non-perturbative numerical methods and investigate their
stability by examining the spectrum of the water wave problem linearized about
the resonant traveling wave. Instabilities are observed that differ from any
previously found in the context of the water wave problem.",1512.01562v2
2018-10-04,Propagation of Nonlinear Acoustic Waves in the Suspension of Ultrasound Contrast Agents Part I: Equation for Counting Resonance Effects and Revealing Acoustic Localization,"The oscillations of ultrasound contrast agents are of particular importance
to the understanding of the propagation of acoustic waves in the bubbly liquids
(suspensions of ultrasound contrast agents). Acoustic waves propagating in
bubbly liquids have been investigated extensively. Little has been dedicated to
the resonance effects of the microbubbles on the propagating waves. Here a
nonlinear partial differential equation for describing one-dimensional acoustic
waves propagating near the resonance frequency of the microbubbles in bubbly
liquids is obtained. The present equation recovers classical results for
propagating acoustic waves with finite amplitudes in liquids and interprets the
acoustic localization in bubbly liquids explicitly.",1810.02063v1
2009-06-16,Finite-Dimensional Turbulence of Planetary Waves,"Finite-dimensional wave turbulence refers to the chaotic dynamics of
interacting wave `clusters' consisting of finite number of connected wave
triads with exact three-wave resonances. We examine this phenomenon using the
example of atmospheric planetary (Rossby) waves. It is shown that the dynamics
of the clusters is determined by the types of connections between neighboring
triads within a cluster; these correspond to substantially different scenarios
of energy flux between different triads. All the possible cases of the energy
cascade termination are classified. Free and forced chaotic dynamics in the
clusters are investigated: due to the huge fluctuations of the energy exchange
between resonant triads these two types of evolution have a lot in common. It
is confirmed that finite-dimensional wave turbulence in finite wave systems is
fundamentally different from kinetic wave turbulence in infinite systems; the
latter is described by wave kinetic equations that account for interactions
with overlapping quasi-resonances of finite amplitude waves. The present
results are directly applicable to finite-dimensional wave turbulence in any
wave system in finite domains with 3-mode interactions as encountered in
hydrodynamics, astronomy, plasma physics, chemistry, medicine, etc.",0906.2852v1
2013-11-15,Singular evanescent wave resonances,"Resonators fold the path of light by reflections leading to a phase balance
and thus constructive addition of propagating waves. However, amplitude
decrease of these waves due to incomplete reflection or material absorption
leads to a finite quality factor of all resonances. Here we report on our
discovery that evanescent waves can lead to a perfect phase and amplitude
balance causing an ideal Fabry-Perot resonance condition in spite of material
absorption and non-ideal reflectivities. This counterintuitive resonance occurs
if and only if the metallic Fabry-Perot plates are in relative motion to each
other separated by a critical distance. We show that the energy needed to
approach the resonance arises from the conversion of the mechanical energy of
motion to electromagnetic energy. The phenomenon is similar to lasing where the
losses in the cavity resonance are exactly compensated by optical gain media
instead of mechanical motion. Nonlinearities and non-localities in material
response will inevitably curtail any singularities however we show the giant
enhancement in non-equilibrium phenomena due to such resonances in moving
media.",1311.3718v3
2015-05-15,Orbital selectivity and emergent superconducting state from quasi-degenerate $s-$ and $d-$wave pairing channels in iron-based superconductors,"A major puzzle about the nature of the iron-based superconductivity appears
in the case of the alkaline iron selenides. Compared to the iron pnictides,
these systems have only electron Fermi pockets (i.e. no hole Fermi pockets) but
comparable superconducting transition temperatures. The challenge lies in
reconciling the two basic experimental features of their superconducting state:
a node-less gap and the existence of a resonance in the spin excitation
spectrum. We propose a mechanism based on reconstructing two quasi-degenerate
pairing states, one in an $s$-wave $A_{1g}$ channel that is fully gapped, and
the other in a $d$-wave $B_{1g}$ channel whose pairing function changes sign
across the electron Fermi pockets at the Brillouin-zone boundary. The resulting
intermediate pairing state, which we call an orbital-selective $s \times
\tau_3$ state, incorporates both of the above two properties. When the leading
spin-singlet pairing is in the $d_{xz}, d_{yz}$ orbital subspace, this state
retains the $s$-wave form factor but has a $B_{1g}$ symmetry due to an internal
$\tau_3$ structure in the orbital space. Within a five-orbital $t-J_{1}-J_{2}$
model with orbital-selective exchange couplings, we show that the proposed
pairing state is energetically competitive over a finite range of control
parameters. We calculate the dynamical spin susceptibility in the
orbital-selective $s \times \tau_3$ superconducting state and show that a spin
resonance arises and has the characteristics of observed by inelastic neutron
experiments in the alkaline iron selenides. More generally, the formation of
the orbital-selective $s \times \tau_3$ state represents a novel means of
relieving the quasi-degeneracy between $s-$ and $d-$wave pairing states, which
is a hitherto unsuspected alternative to the conventional route of linearly
superposing the two into a time-reversal symmetry breaking $s+id$ state.",1505.04170v1
2009-05-13,Observation of spin-wave propagation in permalloy microstripes,"We report on the propagation of spin waves in permalloy microstripes. By
means of scanning Kerr microscopy combined with continuous microwave
excitation, we detect the time evolution of spin-wave interference patterns in
an external magnetic field. Assuming transverse spin-wave quantization we can
directly measure the amplitude, phase velocity and damping for the
corresponding transversal wave mode numbers m. We find that the spin-wave
interference pattern is dominated by m=0 and m=2 with phase velocities v_0=71
km/s and v_2=47 km/s, respectively.",0905.2172v1
2019-07-21,Superradiant parametric conversion of spin waves,"Atomic-ensemble spin waves carrying single-photon Fock states exhibit
nonclassical many-body correlations in-between atoms. The same correlations are
inherently associated with single-photon superradiance, forming the basis of a
plethora of quantum light-matter interfaces. We devise a scheme allowing the
preparation of spatially-structured superradiant states in the atomic
two-photon cascade using spin-wave light storage. We thus show that long-lived
atomic ground-state spin waves can be converted to photon pairs opening the way
towards nonlinear optics of spin waves via multi-wave mixing processes.",1907.09001v2
2005-09-15,Cubic magnets with Dzyaloshinskii-Moriya interaction at low T,"Ground state and spin-wave spectrum of cubic magnets with the
Dzyaloshinskii-Moriya interaction (DMI) such as MnSi and FeGe are studied
theoretically. The linear spin-wave theory is developed. The spin-wave spectrum
depends strongly on the magnetic field and strongly anisotropic. It is a result
of incommensurate magnetic structure when the DMI breaks the total spin
conservation law. The spin-wave spectrum is unstable at infinitesimal
perpendicular field. If the gap $\Delta$ is introduced the spectrum becomes
stable. The gap appears due to cubic anisotropy and the spin-wave interaction
considered in the Hartree-Fock approximation. Peculiar properties of the ESR
and neutron scattering in the helical magnets are considered and possibilities
of corresponding experimental studies are discussed.",0509406v1
2011-08-30,Spin Wave Diffraction and Perfect Imaging of a Grating,"We study the diffraction of Damon-Eshbach-type spin waves incident on a
one-dimensional grating realized by micro slits in a thin permalloy film. By
means of time-resolved scanning Kerr microscopy we observe unique diffraction
patterns behind the grating which exhibit replications of the spin-wave field
at the slits. We show that these spin-wave images, with details finer than the
wavelength of the incident Damon-Eshbach spin wavelength, arise from the
strongly anisotropic spin wave dispersion.",1108.5883v1
2014-08-15,Separated spin-up and spin-down evolution of degenerated electrons in two dimensional systems: Dispersion of longitudinal collective excitations in plane and nanotube geometry,"Applying the separated spin evolution quantum hydrodynamics to
two-dimensional electron gas in plane samples and nanotubes located in external
magnetic fields we find new kind of wave in electron gas, which is called the
spin-electron acoustic wave. Separate spin-up electrons and spin-down electrons
evolution reveals in replacement of the Langmuir wave by the couple of hybrid
waves. One of two hybrid waves is the modified Langmuir wave. Another hybrid
wave is the spin-electron acoustic wave. We study dispersion of these waves in
two dimensional structures of electrons. We also consider dependence of
dispersion properties on spin polarisation of electrons in external magnetic
field.",1408.3662v1
2017-12-04,Phase-resolved Spin-Wave Tomography,"The propagation dynamics of spin waves are represented by their dispersion
relations. Recently, we have developed a method, called spin-wave tomography
(SWaT), to obtain dispersion relation of spin waves in the long wavelength
regime, so-called pure magnetostatic waves. In our previous studies on SWaT,
phase information of spin waves was disregarded. In this report, we demonstrate
an advanced SWaT analysis, called phase-resolved spin-wave tomography (PSWaT),
to realize the direct observation of the amplitude and the phase of spin waves.
The PSWaT spectra are obtained by separating the real and the imaginary
components of the complex Fourier transform in the SWaT analysis. We
demonstrate the PSWaT spectra of spin waves excited by the photo-induced
demagnetization in a Bi-doped garnet film, reflecting the characteristic
features of the complex dynamical susceptibility affected by magnetostatic
coupling in the film.",1712.00927v2
2017-12-04,"Faster, farther, stronger: spin transfer torque driven high order propagating spin waves in nano-contact magnetic tunnel junctions","Short wave-length exchange-dominated propagating spin waves will enable
magnonic devices to operate at higher frequencies and higher data transmission
rates.1 While GMR based magnetic nano-contacts are highly efficient injectors
of propagating spin waves2,3, the generated wave lengths are 2.6 times the
nano-contact diameter4, and the electrical signal strength remains much too
weak for practical applications. Here we demonstrate nano-contact based spin
wave generation in magnetic tunnel junction stacks, and observe large discrete
frequency steps consistent with the hitherto ignored possibility of second and
third order propagating spin waves with wave lengths of 120 and 74 nm, i.e.
much smaller than the 150 nm nano-contact. These higher-order propagating spin
waves will not only enable magnonic devices to operate at much higher
frequencies, but also greatly increase their transmission rates and spin wave
propagating lengths, both proportional to the much higher group velocity.",1712.00954v2
2018-01-17,Exploring Hidden Acoustic Spin Underwater,"Investigating wave propagation in fluid enables a variety of important
applications in underwater communications, object detections and unmanned robot
control. Conventionally, momentum and spin reveal fundamental physical
properties about propagating waves. Yet, vast previous research focused on the
orbital angular momentum of acoustics without thinking about the existence
possibility of spin due to the longitudinal wave nature. Here, we show that
underwater acoustic wave processes the non-trivial spin angular momentum
intrinsically, which is associated with its special spin-orbital coupling
relation for longitudinal waves. Furthermore, we demonstrate that this
intrinsic spin, although unobservable in plane wave form, can be detected by
four approaches: wave interference, Gaussian exponential decay form, boundary
evanescent wave, and waveguide mode. We further show that the strong
spin-orbital coupling can be exploited to achieve unidirectional excitation and
backscattering immune transport. We hope the present results can improve the
geometric and topological understanding about underwater acoustic wave and pave
the way on the spin-related underwater applications.",1801.05790v2
2014-12-10,"Multicomponent long-wave--short-wave resonance interaction system: Bright solitons, energy-sharing collisions, and resonant solitons","We consider a general multicomponent (2+1)-dimensional long-wave--short-wave
resonance interaction (LSRI) system with arbitrary nonlinearity coefficients,
which describes the nonlinear resonance interaction of multiple short waves
with a long-wave in two spatial dimensions. The general multicomponent LSRI
system is shown to be integrable by performing the Painlev\'e analysis. Then we
construct the exact bright multi-soliton solutions by applying the Hirota's
bilinearization method and study the propagation and collision dynamics of
bright solitons in detail. Particularly, we investigate the head-on and
overtaking collisions of bright solitons and explore two types of
energy-sharing collisions as well as standard elastic collision. We have also
corroborated the obtained analytical one-soliton solution by direct numerical
simulation. Also, we discuss the formation and dynamics of resonant solitons.
Interestingly, we demonstrate the formation of resonant solitons admitting
breather-like (localized periodic pulse train) structure and also large
amplitude localized structures akin to rogue waves coexisting with solitons.
For completeness, we have also obtained dark one- and two-soliton solutions and
studied their dynamics briefly.",1412.3201v1
2007-04-23,Feasibility Study of Logic Circuits with Spin Wave Bus,"We present a feasibility study of logic circuits utilizing spin waves for
information transmission and processing. As an alternative approach to the
transistor-based architecture, logic circuits with spin wave bus do not use
charge as an information carrier. In this work we describe the general concept
of logic circuits with spin wave bus and illustrate its performance by
numerical simulations based on available experimental data. Theoretical
estimates and results of numerical simulations on signal attenuation, signal
phase velocity, and the minimum spin wave energy required per bit in the spin
bus are obtained. The transport parameters are compared with ones for
conventional electronic transmission lines. Spin Wave Bus is not intended to
substitute traditional metal interconnects since it has higher signal
attenuation and lower signal propagation speed. The potential value of spin
wave bus is, however, an interface between electronic circuits and integrated
spintronics circuits. The logic circuits with spin wave bus allow us to provide
wireless read-in and read-out.",0704.2862v1
2015-06-02,Effects of frustration and cyclic exchange on the spin-1/2 Heisenberg antiferromagnet within the self-consistent spin-wave theory,"The relevance of the quasi-two-dimensional spin-1/2 frustrated quantum
antiferromagnet due to its possibility of modelling the high-temperature
superconducting parent compounds has resulted in numerous theoretical and
experimental studies. This paper presents a detailed research of the influence
of the varying exchange interactions on the model magnetic properties within
the framework of self-consistent spin-wave theory based on Dyson-Maleev
representation. Beside the nearest neighbour interaction within the plane, the
planar frustration up to the third nearest neighbours, cyclic interaction and
the interlayer coupling are taken into account. The detailed description of the
elementary spin excitations, staggered magnetization, spin-wave velocity
renormalization factor and ground-state energy is given. The results are
compared to the predictions of the linear spin-wave theory and when possible
also to the second-order perturbative spin-wave expansion results. Finally,
having at our disposal improved experimental results for the in-plane spin-wave
dispersion in high-$T_c$ copper oxide $\mbox{La}_2\mbox{CuO}_4$, the
self-consistent spin-wave theory is applied to that compound in order to
correct earlier obtained set of exchange parameters and high temperature
spin-wave dispersion.",1506.00773v1
2019-06-20,Purely magnetic logic based on polarized spin waves,"Spin wave, the precession of magnetic order in magnetic materials, is a
collective excitation that carries spin angular momentum. Similar to the
acoustic or optical waves, the spin wave also possesses the polarization degree
of freedom. Although such polarization degrees of freedom are frozen in
ferromagnets, they are fully unlocked in antiferromagnets or ferrimagnets. Here
we introduce the concept of magnetic gating and demonstrate a spin wave analog
of the Datta-Das spin transistor in antiferromagnet. Utilizing the interplay
between polarized spin wave and the antiferromagnetic domain walls, we propose
a universal logic gate of pure magnetic nature, which realizes all Boolean
operations in one single magnetic structure. We further construct a full
functional 4-bit Arithmetic Logic Unit using only sixteen spin wave universal
logic gates, operating in a weaving fashion as a Jacquard loom machine. The
spin wave-based architecture proposed here also sets a model for the future
energy efficient non-volatile computing, the distributed processing-in-memory
computing, and the evolvable neuromorphic computing.",1906.08702v1
2004-05-20,Strength of Higher-Order Spin-Orbit Resonances,"When polarized particles are accelerated in a synchrotron, the spin
precession can be periodically driven by Fourier components of the
electromagnetic fields through which the particles travel. This leads to
resonant perturbations when the spin-precession frequency is close to a linear
combination of the orbital frequencies. When such resonance conditions are
crossed, partial depolarization or spin flip can occur. The amount of
polarization that survives after resonance crossing is a function of the
resonance strength and the crossing speed. This function is commonly called the
Froissart-Stora formula. It is very useful for predicting the amount of
polarization after an acceleration cycle of a synchrotron or for computing the
required speed of the acceleration cycle to maintain a required amount of
polarization. However, the resonance strength could in general only be computed
for first-order resonances and for synchrotron sidebands. When Siberian Snakes
adjust the spin tune to be 1/2, as is required for high energy accelerators,
first-order resonances do not appear and higher-order resonances become
dominant. Here we will introduce the strength of a higher-order spin-orbit
resonance, and also present an efficient method of computing it. Several
tracking examples will show that the so computed resonance strength can indeed
be used in the Froissart-Stora formula. HERA-p is used for these examples which
demonstrate that our results are very relevant for existing accelerators.",0405108v1
2006-10-02,Josephson Spin Current in Triplet Superconductor Junctions,"This paper theoretically discusses the spin current in spin-triplet
superconductor / insulator / spin-triplet superconductor junctions. At low
temperatures, a midgap Andreev resonant state anomalously enhances not only the
charge current but also the spin current. The coupling between the Cooper pairs
and the electromagnetic fields leads to the Frounhofer pattern in the direct
current spin flow in magnetic fields and the alternative spin current under
applied bias-voltages.",0610029v1
2010-05-20,Cavity spin optodynamics,"The dynamics of a large quantum spin coupled parametrically to an optical
resonator is treated in analogy with the motion of a cantilever in cavity
optomechanics. New spin optodynamic phenonmena are predicted, such as
cavity-spin bistability, optodynamic spin-precession frequency shifts, coherent
amplification and damping of spin, and the spin optodynamic squeezing of light.",1005.3853v2
2020-01-24,Optical Resonance Shift Spin Noise Spectroscopy,"Quantum spin fluctuations provide a unique way to study spin dynamics without
system perturbation. Here we put forward an optical resonance shift spin noise
spectroscopy as a powerful tool to measure the spin noise of various systems
from magnetic impurities in solids to free atoms and molecules. The quantum
spin fluctuations in these systems can shift the optical resonances by more
than the homogeneous linewidth and produce huge Faraday rotation noise. We
demonstrate, that the resonance shift spin noise spectroscopy gives access to
the high order spin correlators, which contain complete information about the
spin dynamics in contrast with the second order correlator measured by
conventional Pauli-blocking spin noise spectroscopy. The high order quantum
spin correlators manifest themselves as a comb of peaks in the Faraday rotation
noise spectra in transverse magnetic field. This effect is closely related with
the multispin flip Raman scattering observed in the Mn-doped nanostructures.",2001.09060v1
2014-03-13,All-optical NMR in semiconductors provided by resonant cooling of nuclear spins interacting with electrons in the resonant spin amplification regime,"Resonant cooling of different nuclear isotopes manifested in
optically-induced nuclear magnetic resonances (NMR) is observed in n-doped
CdTe/(Cd,Mg)Te and ZnSe/(Zn,Mg)Se quantum wells and for donor-bound electrons
in ZnSe:F and GaAs epilayers. By time-resolved Kerr rotation used in the regime
of resonant spin amplification we can expand the range of magnetic fields where
the effect can be observed up to nuclear Larmor frequencies of 170 kHz. The
mechanism of the resonant cooling of the nuclear spin system is analyzed
theoretically. The developed approach allows us to model the resonant spin
amplification signals with NMR resonances.",1403.3288v1
2019-09-24,Tuning high-Q superconducting resonators by magnetic field reorientation,"Superconducting resonators interfaced with paramagnetic spin ensembles are
used to increase the sensitivity of electron spin resonance experiments and are
key elements of microwave quantum memories. Certain spin systems that are
promising for such quantum memories possess 'sweet spots' at particular
combinations of magnetic fields and frequencies, where spin coherence times or
linewidths become particularly favorable. In order to be able to couple high-Q
superconducting resonators to such specific spin transitions, it is necessary
to be able to tune the resonator frequency under a constant magnetic field
amplitude. Here, we demonstrate a high quality, magnetic field resilient
superconducting resonator, using a 3D vector magnet to continuously tune its
resonance frequency by adjusting the orientation of the magnetic field. The
resonator maintains a quality factor of $> 10^5$ up to magnetic fields of 2.6
T, applied predominantly in the plane of the superconductor. We achieve a
continuous tuning of up to 30 MHz by rotating the magnetic field vector,
introducing a component of 5 mT perpendicular to the superconductor.",1909.11020v3
2004-07-08,Neutrino Oscillations at Supernova Core Bounce Generate the Strongest Gravitational-Wave Bursts,"During the core bounce of a supernova collapse resonant active-to-active
($\nu_a \to \nu_a$), as well as active-to-sterile ($\nu_a \to \nu_s$) neutrino
($\nu$) oscillations can take place. Besides, over this phase weak magnetism
increases antineutrino ($\bar{\nu}$) mean free paths, and thus its luminosity.
Because the oscillation feeds mass-energy into the target $\nu$ species, the
large mass-squared difference between species ($\nu_a \to \nu_s$) implies a
huge amount of power to be given off as gravitational waves ($L_{\textrm{GWs}}
\sim 10^{49}erg s$^{-1}$), due to anisotropic but coherent $\nu$ flow over the
oscillation length. This anisotropy in the $\nu$-flux is driven by both the
{\it universal spin-rotation} and the spin-magnetic coupling. The new spacetime
strain estimated this way is still several orders of magnitude larger than
those from $\nu$ diffusion (convection and cooling) or quadrupole moments of
the neutron star matter. This new feature turns these bursts the more promising
supernova gravitational-wave signal that may be detected by observatories as
LIGO, VIRGO, etc., for distances far out to the VIRGO cluster of galaxies.",0407184v1
2007-12-24,Rabi oscillations in semiconductor multi-wave mixing response,"We studied the semiconductor response with respect to high intensity resonant
excitation on short time scale when the contribution of the Fermi statistics of
the electrons and holes prevails. We studied both the single and double pulse
excitations. For the latter case we considered the time evolution of the
multi-wave mixing exciton polarization. The main difference between the
excitation by a single pulse or by two non-collinear pulses is that the Rabi
oscillations of the multi-wave mixing response are characterized by two
harmonics. Analyzing the operator dynamics governed by the external excitation
we found that there are three invariant spin classes, which do not mix with the
evolution of the system. Two classes correspond to the bright exciton states
and one contains all dark states. We found that the dynamics of the classes is
described by six frequencies and the Rabi frequencies are only two of them (one
for each bright class). We discuss the effect of the dispersion of the
electrons and holes and the Coulomb interaction describing the semiconductor by
the semiconductor Bloch equation (SBE). We show that if initially the system is
in the ground state then the SBE preserves the invariant spin classes thus
proving absence of the dark excitons in the framework of this description. We
found that due to the mass difference between holes of different kind
additional Rabi frequencies, two of those present in the operator dynamics,
should appear in the evolution of the exciton polarization.",0712.4022v2
2019-11-29,Freed-Isobar Analysis of Light Mesons at COMPASS,"Modern hadron-spectroscopy experiments such as COMPASS collect data samples
of unprecedented size, so that novel analysis techniques become possible and
necessary. One such technique is the freed-isobar partial-wave analysis (PWA).
In this approach, fixed parametrizations for the amplitudes of intermediate
states commonly modeled using Breit-Wigner shapes are replaced by sets of
step-like functions that are determined from the data. This approach not only
reduces the model dependence of partial-wave analyses, but also allows us to
study the amplitudes of the intermediate states and their dependence on the
parent system.
  We will also present results of a freed-isobar PWA performed on the large
data set on diffractive production of three charged pions collected by the
COMPASS experiment, which consists of $46\times10^6$ exclusive events. We will
focus on results for the wave with spin-exotic quantum numbers $J^{PC}=1^{-+}$,
in particular on its decay into $\rho(770)\pi$. Here, the freed-isobar PWA
method provides insight into the interplay of three- and two-particle dynamics
and confirms the decay of the spin-exotic $\pi_1(1600)$ resonance to
$\rho(770)\pi$ in a model-independent way.",1911.12907v1
2019-12-12,"Topological Lattice Metamaterials -- A Platform For Novel Electromagnetic Material Design Based On An Artificial Topological ""Atom""","In nature, most materials are composed of atoms with periodic structures.
Hence, it's impossible to introduce topological structures into their lattice
compose, because the atoms as basic blocks cannot be modulated. However, the
lattice compose of metamaterials can be designed conveniently. In our work, we
propose to introduce topological non-trivial structures, Mobius unknots, as the
basic block (the artificial chiral ""atoms"") to design metamaterials. A 5.95 GHz
intrinsic peak, in addition to the electrical resonance peak near 11 GHz on the
transmission coefficient spectrum was confirmed by theoretical calculations,
finite-difference time-domain (FDTD) simulations and experiments when
electromagnetic waves transfer to a chiral Mobius unknot. Theoretical analysis
indicates that this intrinsic peak originates from the phase transition caused
by the electromagnetic waves propagate along the Mobius unknot non-trivial
structure. It is similar to the state of spin-splitting of electron levels.
Take the artificial chiral ""atoms"" - Mobius unknots as the basic block, we can
construct two-dimensional and even three-dimensional ordered metamaterials. The
simulation and experimental results showed that the response to electromagnetic
wave in the GHz band can be modulated by the coupling between the periodic
potential and the spin-like of energy levels.",1912.05804v2
2023-05-25,Tuning charge density wave order and structure via uniaxial stress in a stripe-ordered cuprate superconductor,"Unidirectional spin and charge density wave order in the cuprates is known to
compete with superconductivity. In the stripe order (La,M)$_2$CuO$_4$ family of
cuprates, spin and charge order occur as unidirectional order that can be
stabilized by symmetry breaking structural distortions, such as the low
temperature tetragonal (LTT) phase. Here we examine the interplay between
structure and the formation of charge density wave (CDW) order in the LTT phase
of La$_{1.475}$Nd$_{0.4}$Sr$_{0.125}$CuO$_4$ by applying uniaxial stress to
distort the structure and influence the formation of CDW order. Using resonant
soft x-ray scattering to measure both the CDW order and (0 0 1)
structural-nematic Bragg peaks, we find that the application of uniaxial stress
along the Cu-O bond direction suppresses the (0 0 1) peak and has the net
effect of reducing CDW order, but does so only for CDW order propagating
parallel to the applied stress. We connect these observations to previous work
showing an enhanced superconducting transition temperature under uniaxial
stress; providing insight into how CDW, superconductivity, nematicity, and
structure are related and can be tuned relative to one another in cuprates.",2305.16499v2
2023-02-21,Amplification and frequency conversion of spin waves using acoustic waves,"We numerically study the acoustic parametric amplification of spin waves
using surface acoustic waves (SAW) in a magnetic thin film. First, we
illustrate how the process of parametric spin-wave generation using short-waved
SAWs with a fixed frequency allows to tune frequencies of the generated spin
waves by the applied magnetic field. We further present the amplification of
microwave driven spin waves using this method. The decay length and the
amplitude of the driven spin waves can be amplified up to approximately 2.5 and
10 times compared to the reference signal, respectively. More importantly, the
proposed design can be used as a frequency converter, in which a low (high)
frequency spin-wave mode stimulates the excitation of a high (low) frequency
mode. Our results pave the way in designing highly flexible and efficient
hybrid magnonic device architectures for microwave data transport and
processing.",2302.10614v1
2014-03-17,Dynamic strain-mediated coupling of a single diamond spin to a mechanical resonator,"The development of hybrid quantum systems is central to the advancement of
emerging quantum technologies, including quantum information science and
quantum-assisted sensing. The recent demonstration of high quality
single-crystal diamond resonators has led to significant interest in a hybrid
system consisting of nitrogen-vacancy center spins that interact with the
resonant phonon modes of a macroscopic mechanical resonator through crystal
strain. However, the nitrogen-vacancy spin-strain interaction has not been well
characterized. Here, we demonstrate dynamic, strain-mediated coupling of the
mechanical motion of a diamond cantilever to the spin of an embedded
nitrogen-vacancy center. Via quantum control of the spin, we quantitatively
characterize the axial and transverse strain sensitivities of the
nitrogen-vacancy ground state spin. The nitrogen-vacancy center is an atomic
scale sensor and we demonstrate spin-based strain imaging with a strain
sensitivity of 3 10^(-6) strain Hz^(-1/2). Finally, we show how this
spin-resonator system could enable coherent spin-phonon interactions in the
quantum regime.",1403.4173v3
2017-07-11,Hole spin resonance and spin-orbit coupling in a silicon metal-oxide-semiconductor field-effect transistor,"We study hole spin resonance in a p-channel silicon metal-oxide-semiconductor
field-effect transistor. In the sub-threshold region, the measured source-drain
current reveals a double dot in the channel. The observed spin resonance
spectra agree with a model of strongly coupled two-spin states in the presence
of a spin-orbit-induced anti-crossing. Detailed spectroscopy at the
anti-crossing shows a suppressed spin resonance signal due to
spin-orbit-induced quantum state mixing. This suppression is also observed for
multi-photon spin resonances. Our experimental observations agree with
theoretical calculations.",1707.03106v1
2002-10-23,170 Nanometer Nuclear Magnetic Resonance Imaging using Magnetic Resonance Force Microscopy,"We demonstrate one-dimensional nuclear magnetic resonance imaging of the
semiconductor GaAs with 170 nanometer slice separation and resolve two regions
of reduced nuclear spin polarization density separated by only 500 nanometers.
This is achieved by force detection of the magnetic resonance, Magnetic
Resonance Force Microscopy (MRFM), in combination with optical pumping to
increase the nuclear spin polarization. Optical pumping of the GaAs creates
spin polarization up to 12 times larger than the thermal nuclear spin
polarization at 5 K and 4 T. The experiment is sensitive to sample volumes
containing $\sim 4 \times 10^{11}$ $^{71}$Ga$/\sqrt{Hz}$. These results
demonstrate the ability of force-detected magnetic resonance to apply magnetic
resonance imaging to semiconductor devices and other nanostructures.",0210099v1
2021-07-21,Parametric longitudinal coupling between a high-impedance superconducting resonator and a semiconductor quantum dot singlet-triplet spin qubit,"Long-distance two-qubit coupling, mediated by a superconducting resonator, is
a leading paradigm for performing entangling operations in a quantum computer
based on spins in semiconducting materials. Here, we demonstrate a novel,
controllable spin-photon coupling based on a longitudinal interaction between a
spin qubit and a resonator. We show that coupling a singlet-triplet qubit to a
high-impedance superconducting resonator can produce the desired longitudinal
coupling when the qubit is driven near the resonator's frequency. We measure
the energy splitting of the qubit as a function of the drive amplitude and
frequency of a microwave signal applied near the resonator antinode, revealing
pronounced effects close to the resonator frequency due to longitudinal
coupling. By tuning the amplitude of the drive, we reach a regime with
longitudinal coupling exceeding $1$ MHz. This demonstrates a new mechanism for
qubit-resonator coupling, and represents a stepping stone towards producing
high-fidelity two-qubit gates mediated by a superconducting resonator.",2107.10269v1
2015-04-28,Microwave soft x-ray microscopy for nanoscale magnetization dynamics in the 5-10 GHz frequency range,"We present a scanning transmission x-ray microscopy setup combined with a
novel microwave synchronization scheme in order to study high frequency
magnetization dynamics at synchrotron light sources. The sensitivity necessary
to detect small changes of the magnetization on short time scales and nanometer
spatial dimensions is achieved by combination of the developed excitation
mechanism with a single photon counting electronics that is locked to the
synchrotron operation frequency. The required mechanical stability is achieved
by a compact design of the microscope. Our instrument is capable of creating
direct images of dynamical phenomena in the 5-10 GHz range, with 35 nm
resolution. When used together with circularly polarized x-rays, the above
capabilities can be combined to study magnetic phenomena at microwave
frequencies, such as ferromagnetic resonance (FMR) and spin waves. We
demonstrate the capabilities of our technique by presenting phase resolved
images of a 6 GHz nanoscale spin wave generated by a spin torque oscillator, as
well as the uniform ferromagnetic precession with ~0.1 deg amplitude at 9 GHz
in a micrometer-sized cobalt strip.",1504.07561v1
2015-10-08,Spin excitations in a model of FeSe with orbital ordering,"We present a theoretical study of the dynamical spin susceptibility for the
intriguing Fe-based superconductor FeSe, based on a tight-binding model
developed to account for the temperature-dependent band structure in this
system. The model allows for orbital ordering in the $d_{xz}/d_{yz}$ channel
below the structural transition and presents a strongly $C_4$ symmetry broken
Fermi surface at low temperatures which accounts for the nematic properties of
this material. The calculated spin excitations are peaked at wave vector
$(\pi,0)$ in the 1-Fe Brillouin zone, with a broad maximum at energies of order
a few meV. In this range, the occurrence of superconductivity sharpens this
peak in energy, creating a $(\pi,0)$ ""neutron resonance"" as seen in recent
experiments. With the exception of the quite low energy scale of these
fluctuations, these results are roughly similar to standard behavior in Fe
pnictide systems. At higher energies, however, intensity increases and shifts
to wave vectors along the $(\pi,0)$ - $(\pi,\pi)$ line. We compare with
existing inelastic neutron experiments and NMR data, and give predictions for
further studies.",1510.02357v2
2017-07-09,Signatures of pairing in the magnetic excitation spectrum of strongly correlated ladders,"Magnetic interactions are widely believed to play a crucial role in the
microscopic mechanism leading to high critical temperature superconductivity.
It is therefore important to study the signatures of pairing in the magnetic
excitation spectrum of simple models known to show unconventional
superconducting tendencies. Using the Density Matrix Renormalization Group
technique, we calculate the dynamical spin structure factor $S({\bf k},\omega)$
of a generalized $t-U-J$ Hubbard model away from half-filling in a two-leg
ladder geometry. The addition of $J$ enhances pairing tendencies. We analyze
quantitatively the signatures of pairing in the magnetic excitation spectra. We
found that the superconducting pair-correlation strength, that can be estimated
independently from ground state properties, is closely correlated with the
integrated low-energy magnetic spectral weight in the vicinity of $(\pi,\pi)$.
In this wave-vector region, robust spin incommensurate features develop with
increasing doping. The branch of the spectrum with rung direction wave-vector
$k_{rung}=0$ does not change substantially with doping where pairing dominates,
and thus plays a minor role. We discuss the implications of our results for
neutron scattering experiments, where the spin excitation dynamics of
hole-doped quasi-one dimensional magnetic materials can be measured, and also
address implications for recent resonant inelastic X-ray scattering
experiments.",1707.02626v1
2016-12-22,Bismuth iron garnet Bi3Fe5O12: a room temperature magnetoelectric material,"The possibility to control the magnetic properties of a material with an
electric field at room temperature is highly desirable for modern applications.
Moreover, a coupling between magnetic and electric orders within a single
material presenting a wide range of exceptional physical properties, such as
bismuth iron garnet (BIG), may lead to great advances in the field of
spintronic applications. In particular, the combination of the magnetoelectric
(ME) coupling with the low damping of spin waves in BIG can allow the control
and manipulation of spin waves by an electric field in magnonic devices. Here
we report the unambiguous observation of linear magnetoelectric coupling above
300 K in BIG using ferromagnetic resonance technique with electric field
modulation. The measured coupling value is comparable with that observed for
prototypal magnetoelectric Cr2O3. On the basis of our experimental results, the
strength of this linear ME coupling is directly linked to the presence of
bismuth ions inducing strong spin orbit coupling and to the appearance of local
magnetic inhomogeneities related to the magnetic domain structure. The
unprecedented combination of magnetic, optical and magnetoelectrical properties
in BIG is expected to trigger significant interest for technological
applications as well as for theoretical studies.",1612.07531v3
2019-04-25,High Spin-Wave Propagation Length Consistent with Low Damping in a Metallic Ferromagnet,"We report ultra-low intrinsic magnetic damping in
Co$_{\text{25}}$Fe$_{\text{75}}$ heterostructures, reaching the low $10^{-4}$
regime at room temperature. By using a broadband ferromagnetic resonance
technique, we extracted the dynamic magnetic properties of several
Co$_{\text{25}}$Fe$_{\text{75}}$-based heterostructures with varying
ferromagnetic layer thickness. By estimating the eddy current contribution to
damping, measuring radiative damping and spin pumping effects, we found the
intrinsic damping of a 26\,nm thick sample to be $$\alpha_{\mathrm{0}} \lesssim
3.18\times10^{-4}$. Furthermore, using Brillouin light scattering microscopy we
measured spin-wave propagation lengths of up to $(21\pm1)\,\mathrm{\mu m}$ in a
26 nm thick Co$_{\text{25}}$Fe$_{\text{75}}$ heterostructure at room
temperature, which is in excellent agreement with the measured damping.",1904.11321v3
2020-05-20,Anomalous in-gap edge states in two-dimensional pseudospin-1 Dirac insulators,"Quantum materials that host a flat band, such as pseudospin-1 lattices and
magic-angle twisted bilayer graphene, can exhibit drastically new physical
phenomena including unconventional superconductivity, orbital ferromagnetism,
and Chern insulating behaviors. We report a surprising class of electronic
in-gap edge states in pseudospin-1 materials without the conventional need of
band-inversion topological phase transitions or introducing magnetism via an
external magnetic type of interactions. In particular, we find that, in
two-dimensional gapped (insulating) Dirac systems of massive spin-1
quasiparticles, in-gap edge modes can emerge through only an {\em electrostatic
potential} applied to a finite domain. Associated with these unconventional
edge modes are spontaneous formation of pronounced domain-wall spin textures,
which exhibit the feature of out-of-plane spin-angular momentum locking on both
sides of the domain boundary and are quite robust against boundary deformations
and impurities despite a lack of an explicit topological origin. The in-gap
modes are formally three-component evanescent wave solutions, akin to the
Jackiw-Rebbi type of bound states. Such modes belong to a distinct class due to
the following physical reasons: three-component spinor wave function, unusual
boundary conditions, and a shifted flat band induced by the external scalar
potential. Not only is the finding of fundamental importance, but it also paves
the way for generating highly controllable in-gap edge states with emergent
spin textures using the traditional semiconductor gate technology. Results are
validated using analytic calculations of a continuum Dirac-Weyl model and
tight-binding simulations of realistic materials through characterizations of
local density of state spectra and resonant tunneling conductance.",2005.10183v1
2023-11-05,Topological spin-orbit-coupled fermions beyond rotating wave approximation,"The realization of spin-orbit-coupled ultracold gases has driven a wide range
of researches and is typically based on the rotating wave approximation (RWA).
By neglecting the counter-rotating terms, RWA characterizes a single
near-resonant spin-orbit (SO) coupling in a two-level system. Here, we propose
and experimentally realize a new scheme for achieving a pair of two-dimensional
(2D) SO couplings for ultracold fermions beyond RWA. This work not only
realizes the first anomalous Floquet topological Fermi gas beyond RWA, but also
significantly improves the lifetime of the 2D-SO-coupled Fermi gas. Based on
pump-probe quench measurements, we observe a deterministic phase relation
between two sets of SO couplings, which is characteristic for our beyond-RWA
scheme and enables the two SO couplings to be simultaneously tuned to the
optimum 2D configurations. We observe intriguing band topology by measuring
two-ring band-inversion surfaces, quantitatively consistent with a Floquet
topological Fermi gas in the regime of high Chern numbers. Our study can open
an avenue to explore exotic SO physics and anomalous topological states based
on long-lived SO-coupled ultracold fermions.",2311.02584v1
2024-04-08,Global phase diagram of doped quantum spin liquid on the Kagome lattice,"It has long been believed that doped quantum spin liquids (QSLs) can give
rise to fascinating quantum phases, including the possibility of
high-temperature superconductivity (SC) as proposed by P. W. Anderson's
resonating valence bond (RVB) scenario. The Kagome lattice $t$-$J$ model is
known to exhibit spin liquid behavior at half-filling, making it an ideal
system for studying the properties of doped QSL. In this study, we employ the
fermionic projected entangled simplex state (PESS) method to investigate the
ground state properties of the Kagome lattice $t$-$J$ model with $t/J = 3.0$.
Our results reveal a phase transition from charge density wave (CDW) states to
uniform states around a critical doping level $\delta_c \approx 0.27$. Within
the CDW phase, we observe different types of Wigner crystal (WC) formulated by
doped holes that are energetically favored. As we enter the uniform phase, a
non-Fermi liquid (NFL) state emerges within the doping range $0.27 < \delta <
0.32$, characterized by an exponential decay of all correlation functions. With
further hole doping, we discover the appearance of a pair density wave (PDW)
state within a narrow doping region $0.32 < \delta < 1/3$. We also discuss the
potential experimental implications of our findings.",2404.05685v1
2015-07-29,Resonance Van Hove Singularities in Wave Kinetics,"Wave kinetic theory has been developed to describe the statistical dynamics
of weakly nonlinear, dispersive waves. However, we show that systems which are
generally dispersive can have resonant sets of wave modes with identical group
velocities, leading to a local breakdown of dispersivity. This shows up as a
geometric singularity of the resonant manifold and possibly as an infinite
phase measure in the collision integral. Such singularities occur widely for
classical wave systems, including acoustical waves, Rossby waves, helical waves
in rotating fluids, light waves in nonlinear optics and also in quantum
transport, e.g. kinetics of electron-hole excitations (matter waves) in
graphene. These singularities are the exact analogue of the critical points
found by Van Hove in 1953 for phonon dispersion relations in crystals. The
importance of these singularities in wave kinetics depends on the dimension of
phase space $D=(N-2)d$ ($d$ physical space dimension, $N$ the number of waves
in resonance) and the degree of degeneracy $\delta$ of the critical points.
Following Van Hove, we show that non-degenerate singularities lead to finite
phase measures for $D>2$ but produce divergences when $D\leq 2$ and possible
breakdown of wave kinetics if the collision integral itself becomes too large
(or even infinite). Similar divergences and possible breakdown can occur for
degenerate singularities, when $D-\delta\leq 2,$ as we find for several
physical examples, including electron-hole kinetics in graphene. When the
standard kinetic equation breaks down, then one must develop a new singular
wave kinetics. We discuss approaches from pioneering 1971 work of Newell \&
Aucoin on multi-scale perturbation theory for acoustic waves and
field-theoretic methods based on exact Schwinger-Dyson integral equations for
the wave dynamics.",1507.08320v1
2020-01-14,Close-to-touching acoustic subwavelength resonators: eigenfrequency separation and gradient blow-up,"In this paper, we study the behaviour of the coupled subwavelength resonant
modes when two high-contrast acoustic resonators are brought close together. We
consider the case of spherical resonators and use bispherical coordinates to
derive explicit representations for the capacitance coefficients which, we
show, capture the system's resonant behaviour at leading order. We prove that
the pair of resonators has two subwavelength resonant modes whose frequencies
have different leading-order asymptotic behaviour. We, also, derive estimates
for the rate at which the gradient of the scattered pressure wave blows up as
the resonators are brought together.",2001.04888v2
2017-08-19,Current induced multi-mode propagating spin waves in a spin transfer torque nano-contact with strong perpendicular magnetic anisotropy,"Current induced spin wave excitations in spin transfer torque nano-contacts
are known as a promising way to generate exchange-dominated spin waves at the
nano-scale. It has been shown that when these systems are magnetized in the
film plane, broken spatial symmetry of the field around the nano-contact
induced by the Oersted field opens the possibility for spin wave mode
co-existence including a non-linear self-localized spin-wave bullet and a
propagating mode. By means of micromagnetic simulations, here we show that in
systems with strong perpendicular magnetic anisotropy (PMA) in the free layer,
two propagating spin wave modes with different frequency and spatial
distribution can be excited simultaneously. Our results indicate that in-plane
magnetized spin transfer nano-contacts in PMA materials do not host a solitonic
self-localized spin-wave bullet, which is different from previous studies for
systems with in plane magnetic anisotropy. This feature renders them
interesting for nano-scale magnonic waveguides and crystals since magnon
transport can be configured by tuning the applied current.",1708.05886v1
2018-07-19,Spin-wave amplification and lasing driven by inhomogeneous spin transfer torques,"We show that an inhomogeneity in the spin-transfer torques in a metallic
ferromagnet under suitable conditions strongly amplifies incoming spin waves.
Moreover, at nonzero temperatures the incoming thermally occupied spin waves
will be amplified such that the region with inhomogeneous spin transfer torques
emits spin waves spontaneously, thus constituting a spin-wave laser. We
determine the spin-wave scattering amplitudes for a simplified model and
set-up, and show under which conditions the amplification and lasing occurs.
Our results are interpreted in terms of a so-called black-hole laser, and could
facilitate the field of magnonics, that aims to utilize spin waves in logic and
data-processing devices.",1807.07312v1
2023-05-08,On the Origin of Acoustic Spin and Elastic Spin: Uncovering Hidden Wave Spin of Scalar Fields with Higher-Order Derivative Lagrangian,"Scalar field should have no spin angular momentum according to conventional
understandings in classical field theory. Yet, recent studies demonstrate the
undoubted existence of wave spin endowed by acoustic and elastic longitudinal
waves, which are of irrotational curl-free nature without vorticity and can be
described by scalar fields. Here, to solve this seeming discrepancy, we uncover
the origin of wave spin in scalar fields beyond traditional formalism by
clarifying that the presence of higher order derivatives in scalar field
Lagrangians can give rise to non-vanishing spin. For scalar fields with only
first order derivative, we can make the hidden wave spin emerge, by
constructing a latent field that leads to the original field through a time
derivative so that is of second order. We exemplify the wave spin for elastic
and acoustic fields, as well as for dissipative media, following Noether's
theorem in higher-order derivative Lagrangian. The results would prompt people
to build more comprehensive and fundamental understandings of structural wave
spin in classical fields.",2305.04939v1
2007-10-25,Optical detection of single electron spin resonance in a quantum dot,"We demonstrate optically detected spin resonance of a single electron
confined to a self-assembled quantum dot. The dot is rendered dark by resonant
optical pumping of the spin with a coherent laser. Contrast is restored by
applying a radio frequency (rf) magnetic field at the spin resonance. The
scheme is sensitive even to rf fields of just a few micro-T. In one case, the
spin resonance behaves exactly as a driven 3-level quantum system (a
lambda-system) with weak damping. In another, the dot exhibits remarkably
strong (67% signal recovery) and narrow (0.34 MHz) spin resonances with
fluctuating resonant positions, evidence of unusual dynamic processes of
non-Markovian character.",0710.4901v1
2021-10-11,Spin pumping at terahertz nutation resonances,"We investigate spin pumping current injected by the nutation resonances of a
ferromagnet or an antiferromagnet into an adjacent metal. Comparing the dc spin
pumping current between the normal precession and nutation resonances, we find
that the ratio of spin pumping current at the nutation resonance to the
precession resonance is more pronounced in antiferromagnets. We further show
that the spin pumping current injected by the nutation resonance is opposite in
sign as compared to the normal precession mode. This could offer a useful
experimental signature for identifying such nutation resonances. Analyzing the
nature of the nutational eigenmodes, we show that the sign change in spin
current is rooted in a reversal of the precession sense for the nutation
mode(s). Furthermore, the nutational modes in antiferromagnets are found to be
dominated by precession of one of the two sublattices only.",2110.05136v2
2000-04-18,Modified spin-wave description of the nuclear spin relaxation in ferrimagnetic Heisenberg chains,"We make a modified spin-wave description of the nuclear spin relaxation in
Heisenberg alternating-spin chains with antiferromagnetic exchange coupling. In
contrast with the conventional one-dimensional antiferromagnetic spin-wave
theory, which is plagued with the divergence of the sublattice magnetization
even in the ground state, the present spin-wave description is highly
successful over a wide temperature range. The temperature dependence of the
relaxation rate $T_1^{-1}$ significantly varies with the crystalline structure,
exhibiting both ferromagnetic and antiferromagnetic aspects. $T_1^{-1}$ further
shows a unique dependence on the applied field, which turns out an indirect
observation of the quadratic dispersion relations.",0004297v1
2002-08-30,Spin Waves in Random Spin Chains,"We study quantum spin-1/2 Heisenberg ferromagnetic chains with dilute, random
antiferromagnetic impurity bonds with modified spin-wave theory. By describing
thermal excitations in the language of spin waves, we successfully observe a
low-temperature Curie susceptibility due to formation of large spin clusters
first predicted by the real-space renormalization-group approach, as well as a
crossover to a pure ferromagnetic spin chain behavior at intermediate and high
temperatures. We compare our results of the modified spin-wave theory to
quantum Monte Carlo simulations.",0208607v1
2020-02-02,A millimeter-wave Bell Test using a ferrite parametric amplifier and a homodyne interferometer,"A combined ferrite parametric amplifier and millimeter-wave homodyne
interferometer are proposed as an ambient temperature Bell Test. It is shown
that the non-linear magnetic susceptibility of the yttrium iron garnet (YIG)
ferrite, on account of its narrow line-width Larmor precessional resonance,
make it an ideal material for the creation of entangled photons. These can be
measured using a homodyne interferometer, as the much larger number of
thermally generated photons associated with ambient temperature emission can be
screened out. The proposed architecture may enable YIG quantum technology-based
sensors to be developed, mimicking in the millimeter-wave band the large number
of quantum optical experiments in the near-infrared and visible regions which
had been made possible by use of the nonlinear beta barium borate
ferroelectric, an analogue of YIG. It is illustrated here how the YIG
parametric amplifier can reproduce quantum optical Type I and Type II wave
interactions, which can be used to create entangled photons in the
millimeter-wave band. It is estimated that when half a cubic centimeter of YIG
crystal is placed in a magnetic field of a few Tesla and pumped with 5 Watts of
millimeter-wave radiation, approximately 0.5x10^12 entangled millimeter-wave
photon pairs per second are generated by the spin-wave interaction. This means
an integration time of only a few tens of seconds is needed for a successful
Bell Test. A successful demonstration of this will lead to novel architectures
of entanglement-based quantum technology room temperature sensors,
re-envisioning YIG as a modern quantum material.",2002.00439v3
2011-02-21,Stable double-resonance optical spring in laser gravitational-wave detectors,"We analyze the optical spring characteristics of a double pumped Fabry-Perot
cavity. A double-resonance optical spring occurs when the optical spring
frequency and the detuning frequency of the cavity coincide. We formulate a
simple criterion for the stability of an optical spring and apply it to the
double resonance regime. Double resonance configurations are very promising for
future gravitational wave detectors as they allow us to surpass the Standard
Quantum Limit. We show that stable double resonance can be demonstrated in
middle scale prototype interferometers such as the Glasgow 10m-Prototype,
Gingin High Optical Power Test Facility or the AEI 10m Prototype Interferometer
before being implemented in future gravitational wave detectors.",1102.4266v1
2017-05-15,Resonance control of graphene drum resonator in nonlinear regime by standing wave of light,"We demonstrate the control of resonance characteristics of a drum type
graphene mechanical resonator in nonlinear oscillation regime by the
photothermal effect, which is induced by a standing wave of light between a
graphene and a substrate. Unlike the conventional Duffing type nonlinearity,
the resonance characteristics in nonlinear oscillation regime is modulated by
the standing wave of light despite a small variation amplitude. From numerical
calculations with a combination of equations of heat and motion with Duffing
type nonlinearity, this can be explained that the photothermal effect causes
delayed modulation of stress or tension of the graphene.",1705.05056v1
2020-06-08,Resonance structure of $^{8}$Be with the two-cluster resonating group method,"A two-cluster microscopic model is applied to study elastic alpha-alpha
scattering and resonance structure of $^{8}$Be. The model is an algebraic
version of the Resonating Group Method, which makes use complete set of
oscillator functions to expand wave function of two-cluster system. Interaction
between clusters is determined by well-known semi-realistic nucleon-nucleon
potentials of Hasegawa-Nagata, Minnesota and Volkov. Detail analysis of
resonance wave functions is carried out in oscillator, coordinate and momentum
spaces. Effects of the Pauli principle on wave functions of the $^{8}$Be
continuous spectrum states are thoroughly studied.",2006.04525v1
2018-03-21,180-degree phase shift of magnetoelastic waves observed by phase-resolved spin-wave tomography,"We have investigated optically-excited magnetoelastic waves by phase-resolved
spin-wave tomography (PSWaT). PSWaT reconstructs dispersion relation of spin
waves together with their phase information by using time-resolved
magneto-optical imaging for spin-wave propagation followed by an analysis based
on the convolution theorem and a complex Fourier transform. In PSWaT spectra
for a Bi-doped garnet film, we found a 180 degree phase shift of magnetoelastic
waves at around the crossing of the dispersion relations of spin and elastic
waves. The result is explained by a coupling between spin waves and elastic
waves through magnetoelastic interaction. We also propose an efficient way for
phase manipulation of magnetoelastic waves by rotating the orientation of
magnetization less than 10 degree.",1803.07697v1
2004-02-05,Resonance-like electrical control of electron spin for microwave measurement,"We demonstrate that the spin-polarized electron current can interact with a
microwave electric field in a resonant manner. The spin-orbit interaction gives
rise to an effective magnetic field proportional to the electric current. In
the presence of both dc and ac electric field components, electron spin
resonance occurs if the ac frequency matches with the spin precession frequency
that is controlled by the dc field. In a device consisting of two
spin-polarized contacts connected by a two-dimensional channel, this mechanism
allows electrically tuned detection of the ac signal frequency and amplitude.
For GaAs, such detection is effective in the frequency domain around tens of
gigahertz.",0402172v1
2008-08-05,Electric-Field-Induced Nuclear Spin Resonance Mediated by Oscillating Electron Spin Domains in GaAs-Based Semiconductors,"We demonstrate an alternative nuclear spin resonance using radio frequency
(RF) electric field (nuclear electric resonance: NER) instead of magnetic
field. The NER is based on the electronic control of electron spins forming a
domain structure. The RF electric field applied to a gate excites spatial
oscillations of the domain walls and thus temporal oscillations of the
hyperfine field to nuclear spins. The RF power and burst duration dependence of
the NER spectrum provides insight into the interplay between nuclear spins and
the oscillating domain walls.",0808.0538v1
2013-07-12,Fermi liquid theory of resonant spin pumping,"We study resonant all-electric adiabatic spin pumping through a quantum dot
with two nearby levels by using a Fermi liquid approach in the strongly
interacting regime, combined with a projective numerical renormalization group
(NRG) theory. Due to spin-orbit coupling, a strong spin pumping resonance
emerges at every charging transition, which allows for the transfer of a spin
$~ \hbar/2$ through the device in a single pumping cycle. Depending on the
precise geometry of the device, controlled pure spin pumping is also possible.",1307.3416v2
2021-07-14,Transitionless quantum driving in spin echo,"Spin echo can be used to refocus random dynamical phases caused by
inhomogeneities in control fields and thereby retain the purity of a spatial
distribution of quantum spins. This technique for accurate spin control is an
essential ingredient in many applications, such as nuclear magnetic resonance,
magnetic resonance imaging, and quantum information processing. Here, we show
how all the elements of a spin echo sequence can be performed at high speed by
means of transitionsless quantum driving. This technique promises accurate
control of rapid quantum spin evolution. We apply the scheme to universal
nonadiabatic geometric single- and two-qubit gates in a nuclear magnetic
resonance setting.",2107.06598v2
2015-08-19,Low-Frequency Resonance in Strong Heterogeneity,"Multiple scattering of wave in strong heterogeneity can cause resonance-like
wave anomaly where the signal exhibits low-frequency, high intensity, and
slowly propagating wave packet velocity. For example, long period event in
volcanic seismology and plasma oscillations in wave-particle interactions.
Collective behaviour in a many-body system is thought to be the source for
generating the anomaly, however the detailed mechanism is not fully understood.
Here I show that the physical mechanism is associated with low-frequency
resonance (LFR) in strong small-scale heterogeneity through seismic wave field
modeling for bubble cloud heterogeneity and 1D heterogeneity. LFR is a kind of
wave coherent scattering enhancement or emergence phenomenon that occurs in
transient regime. Its resonance frequency decreases with increasing
heterogeneous scale, impedance contrast, or random heterogeneous scale and
velocity fluctuations; its intensity diminishes with decreasing impedance
contrast or increasing random heterogeneous scale and velocity fluctuations.
LRF exhibits the characteristics of localized wave in space and the shape of
ocean wave in time and is a ubiquitous wave phenomenon in wave physics. The
concept of LFR can open up new opportunities in many aspects of science and
engineering.",1508.04713v5
2017-03-08,On the physical mechanism of centrifugal-gravity wave resonant instability in swirling free surface rotating Polygons,"We present an explicit analysis of wave-resonant instability of swirling
flows inside fast rotating cylindrical containers. The linear dynamics are
decomposed into the interaction between the horizontal inner centrifugal edge
waves, the outer vertical gravity waves with the aim of understanding the
dynamics of the centrifugal waves. We show how the far field velocity induced
respectively by the centrifugal and the gravity waves affect each other's
propagation rates and amplitude growth. We follow this with an analysis of the
instability in terms of a four wave interaction, two centrifugal and two
gravity ones, and explain why the resonant instability can be obtained only
between a pair of two counter-propagating waves, one centrifugal and one
gravity. Furthermore, a near resonant regime which does not yield instability
is shown to result from a phase-locking configuration between a pair of a
counter-propagating centrifugal wave and a pro-propagating gravity one, where
the interaction affects the waves' propagation rates but not the amplitude
growth.",1703.03027v1
2019-05-09,Charmonium resonances with $J^{PC}=1^{--}$ and $3^{--}$ from $\bar DD$ scattering on the lattice,"We present a lattice QCD study of charmonium resonances and bound states with
$J^{PC}=1^{--}$ and $3^{--}$ near the open-charm threshold, taking into account
their strong transitions to $\bar DD$. Vector charmonia are the most abundant
in the experimentally established charmonium spectrum, while recently LHCb
reported also the first discovery of a charmonium with likely spin three. The
$\bar DD$ scattering amplitudes for partial waves $l=1$ and $l=3$ are extracted
on the lattice by means of the L\""uscher formalism, using multiple volumes and
inertial frames. Parameterizations of the scattering amplitudes provide masses
and widths of the resonances, as well as the masses of bound states. CLS
ensembles with 2+1 dynamical flavors of non-perturbatively $O(a)$ improved
Wilson quarks are employed with $m_\pi\simeq 280$ MeV, a single lattice spacing
of $a\simeq0.086$ fm and two lattice spatial extents of $L=24$ and $32$. Two
values of the charm quark mass are considered to examine the influence of the
position of the $\bar{D}D$ threshold on the hadron masses. For the lighter
charm quark mass we find the vector resonance $\psi(3770)$ with mass
$m=3780(7)$ MeV and coupling $g=16.0(^{+2.1}_{-0.2})$ (related to the width),
both consistent with their experimental values. The vector $\psi(2S)$ appears
as a bound state with $m=3666(10)$ MeV. The charmonium resonance with
$J^{PC}=3^{--}$ is found at $m=3831(^{+10}_{-16})$ MeV, consistent with the
$X(3842)$ recently discovered by LHCb. At our heavier charm-quark mass the
$\psi(2S)$ as well as the $\psi(3770)$ are bound states and the $X(3842)$
remains a resonance. We stress that all quoted uncertainties are only
statistical, while lattice spacing effects and the approach to the physical
point still need to be explored. This study of conventional charmonia sets the
stage for more challenging future studies of unconventional charmonium-like
states.",1905.03506v2
2021-12-31,Spin-injection-generated shock waves and solitons in a ferromagnetic thin film: the spin piston problem,"The unsteady, nonlinear magnetization dynamics induced by spin injection in
an easy-plane ferromagnetic channel subject to an external magnetic field are
studied analytically. Leveraging a dispersive hydrodynamic description, the
Landau-Lifshitz equation is recast in terms of hydrodynamic-like variables for
the magnetization's perpendicular component (spin density) and azimuthal phase
gradient (fluid velocity). Spin injection acts as a moving piston that
generates nonlinear, dynamical spin textures in the ferromagnetic channel with
downstream quiescent spin density set by the external field. In contrast to the
classical problem of a piston accelerating a compressible gas, here, variable
spin injection and field lead to a rich variety of nonlinear wave phenomena
from oscillatory spin shocks to solitons and rarefaction waves. A full
classification of solutions is provided using nonlinear wave modulation theory
by identifying two key aspects of the fluid-like dynamics: subsonic/supersonic
conditions and convex/nonconvex hydrodynamic flux. Familiar waveforms from the
classical piston problem such as rarefaction (expansion) waves and shocks
manifest in their spin-based counterparts as smooth and highly oscillatory
transitions, respectively. The spin shock is an example of a dispersive shock
wave, which arises in many physical systems. New features without a gas
dynamics counterpart include composite wave complexes with ""contact"" spin
shocks and rarefactions. Magnetic supersonic conditions lead to two pronounced
piston edge behaviors including a stationary soliton and an oscillatory
wavetrain. These coherent wave structures have physical implications for the
generation of high frequency spin waves from pulsed injection and persistent,
stable stationary and/or propagating solitons in the presence of magnetic
damping. The analytical results are favorably compared with numerical
simulations.",2112.15301v2
2018-04-09,The exact dynamical Chern Simons metric for a spinning black hole possesses a fourth constant of motion: A Dynamical-Systems-Based Conjecture,"The recent gravitational wave observations by the LIGO/Virgo collaboration
have allowed the first tests of General Relativity in the extreme gravity
regime, when comparable-mass black holes and neutron stars collide. Future
space-based detectors, such as the Laser Interferometer Space Antenna, will
allow tests of Einstein's theory with gravitational waves emitted when a small
black hole falls into a supermassive one in an extreme mass-ratio inspiral. One
particular test that is tailor-made for such inspirals is the search for chaos
in extreme gravity. We here study whether chaos is present in the motion of
test particles around spinning black holes of parity-violating modified
gravity, focusing in particular on dynamical Chern-Simons gravity. We develop a
resummation strategy that restores all spin terms in the General Relativity
limit, while retaining up to fifth-order-in-spin terms in the dynamical
Chern-Simons corrections to the Kerr metric. We then calculate Poincar\'e
surfaces of section and rotation numbers of a wide family of geodesics of this
resummed metric. We find no evidence for geodesic chaos, with at most
deformations of the resonant torii that shrink as terms of higher-order in spin
are included in the dynamical Chern-Simons corrections to the Kerr metric. Our
numerical findings suggest that the geodesics of the as-of-yet unknown exact
solution for spinning black holes in this theory may be integrable, and that
there may thus exist a fourth integral of motion associated with this exact
solution. The studies presented here begin to lay the foundations for chaotic
tests of General Relativity with the observation of extreme mass ratio
inspirals with the Laser Interferometer Space Antenna.",1804.04002v2
2021-09-05,Electric field effect on electron gas spins in two-dimensional magnets with strong spin-orbit coupling,"The recent rise of material platforms combining magnetism and
two-dimensionality of mobile carriers reveals a diverse spectrum of spin-orbit
phenomena and stimulates its ongoing theoretical discussions. In this work we
use the density matrix approach to provide a unified description of subtle
microscopic effects governing the electron gas spin behavior in the clean limit
upon electric perturbations in two-dimensional magnets with strong spin-orbit
coupling. We discuss that an inhomogeneity of electrostatic potential generally
leads to the electron gas spin tilting with the subsequent formation of
equilibrium skyrmion-like spin textures and demonstrate that several
microscopic mechanisms of 2DEG spin response are equally important for this
effect. We analyze the dynamics of 2DEG spin upon an oscillating electric field
with a specific focus on the emergent electric dipole spin resonance. We
address the resonant enhancement of magneto-optical phenomena from the spin
precession equation perspective and discuss it in terms of the resonant spin
generation. We also clarify the connection of both static and dynamic spin
phenomena arising in response to a scalar perturbation with the electronic band
Berry curvature.",2109.02151v1
2019-09-11,Determining key spin-orbitronic parameters by means of propagating spin waves,"We characterize spin wave propagation and its modification by an electrical
current in Permalloy(Py)/Pt bilayers with Py thickness between 4 and 20 nm.
First, we analyze the frequency non-reciprocity of surface spin waves and
extract from it the interfacial Dzyaloshinskii-Moriya interaction constant
$D_s$ accounting for an additional contribution due to asymmetric surface
anisotropies. Second, we measure the spin-wave relaxation rate and deduce from
it the Py/Pt spin mixing conductance $g^{\uparrow\downarrow}_{eff}$. Last,
applying a \textit{dc} electrical current, we extract the spin Hall
conductivity $\sigma_{SH}$ from the change of spin wave relaxation rate due to
the spin-Hall spin transfer torque. We obtain a consistent picture of the spin
wave propagation data for different film thicknesses using a single set of
parameters $D_s=0.25$ pJ/m, $g^{\uparrow\downarrow}_{eff} = 3.2\times 10^{19}$
m$^{-2}$ and $\sigma_{SH}=4\times10^{5}$ S/m.",1909.04935v1
2020-05-14,"Modelling spin waves in noncollinear antiferromagnets: spin-flop states, spin spirals, skyrmions and antiskyrmions","Spin waves in antiferromagnetic materials have great potential for
next-generation magnonic technologies. However, their properties and their
dependence on the type of ground-state antiferromagnetic structure are still
open questions. Here, we investigate theoretically spin waves in one- and
two-dimensional model systems with a focus on noncollinear antiferromagnetic
textures such as spin spirals and skyrmions of opposite topological charges. We
address in particular the nonreciprocal spin excitations recently measured in
bulk antiferromagnet $\alpha$--$\text{Cu}_2\text{V}_2\text{O}_7$ utilizing
inelastic neutron scattering experiments [Phys.\ Rev.\ Lett.\ \textbf{119},
047201 (2017)], where we help to characterize the nature of the detected
spin-wave modes. Furthermore, we discuss how the Dzyaloshinskii-Moriya
interaction can lift the degeneracy of the spin-wave modes in antiferromagnets,
resembling the electronic Rashba splitting. We consider the spin-wave
excitations in antiferromagnetic spin-spiral and skyrmion systems and discuss
the features of their inelastic scattering spectra. We demonstrate that
antiskyrmions can be obtained with an isotropic Dzyaloshinskii-Moriya
interaction in certain antiferromagnets.",2005.07250v1
2022-03-19,Spin wave excitation and directional propagation in presence of magnetic charges in square artificial spin ice,"Artificial spin ice is a special class of engineered lattice of highly shape
anisotropic single domain magnetic nanostructures which is used as one of the
model systems to study the spin ice behavior observed in pyrochlore oxides. The
nanomagnets interact via dipolar interaction which results in correlated
magnetization dynamics exhibiting macroscopic spin configuration states. Here,
we exploit the interplay of underlying magnetic state and external bias field
orientation to study controlled spin wave propagation in square Artificial Spin
Ice (sASI) by performing detailed micromagnetic simulations. We report that
careful selection of vertices with local magnetic charges can effectively
direct the anisotropic spin wave in presence of an external field. Further, we
explore the influence of local charges due to the excited state in
even-coordinated vertices as well as uncompensated charges due to
odd-coordinated vertices on spin wave behavior. Our studies suggest that there
is no perceptible difference on spin wave dynamical behavior due to the origin
of local magnetic charge in sASI. Our results of controlled and directional
spin wave propagation in sASI system may be useful for low-power consumption
based all magnonic on-chip devices.",2203.10345v1
1993-09-21,Bound State Soliton Description of Low Partial Wave Octet Baryon Resonances,"A version of the bound state soliton model which allows both $\eta$ and $K$
bound states is used to study low partial wave octet baryon resonances. It is
found that negative parity $S-$wave resonances are well described within this
framework. A possible interpretation of the $P-$wave resonances is also
discussed.",9309305v1
2009-11-08,Resonant guided wave networks,"A resonant guided wave network (RGWN) is an approach to optical materials
design in which power propagation in guided wave circuits enables material
dispersion. The RGWN design, which consists of power-splitting elements
arranged at the nodes of a waveguide network, results in wave dispersion which
depends on network layout due to localized resonances at several length scales
in the network. These structures exhibit both localized resonances with Q ~ 80
at 1550 nm wavelength as well as photonic bands and band-gaps in large periodic
networks at infrared wavelengths.",0911.1567v1
2021-08-19,Resonant tidal responses in rotating fluid bodies: global modes hidden beneath localized wave beams,"In rotating stars and planets, excitation of inertial waves in convective
envelopes provides an important channel for tidal dissipation, but the
dissipation rate due to inertial waves depends erratically on the tidal
frequency. Tidal dissipation is significantly enhanced at some frequencies,
suggesting possible resonances between the tidal forcing and some eigenmodes.
However, the nature of these resonances remains enigmatic owing to the
singularity of the eigenvalue problem of inertial waves, and the resonances are
often mistakenly attributed to wave attractors in the literature. In this
letter, we reveal that resonant tidal responses correspond to inertial modes
with large-scale flows hidden beneath localized wave beams. Strong couplings
between the tidal forcing and the hidden large-scale flows intensify the
localized wave beams emanating from the critical latitudes, leading to enhanced
tidal dissipation. This study resolves a long-standing puzzle regarding the
frequency-dependence of tidal dissipation due to inertial waves in convective
envelopes.",2108.08515v2
2003-04-25,Spin Current Through a Magnetic-Oscillating Quantum Dot,"Non-equilibrium spin transport through an interacting quantum dot is
analyzed. The coherent spin oscillations in the dot provide a generating source
for spin current. In the interacting regime, the Kondo effect is influenced in
a significant way by the presence of the precessing magnetic field. In
particular, when the precession frequency is tuned to resonance between spin up
and spin down states of the dot, Kondo singularity for each spin splits into a
superposition of two resonance peaks. The Kondo-type cotunneling contribution
is manifested by a large enhancement of the pumped spin current in the strong
coupling, low temperature regime.",0304597v1
2010-11-11,Spin Torque Ferromagnetic Resonance Induced by the Spin Hall Effect,"We demonstrate that the spin Hall effect in a thin film with strong
spin-orbit scattering can excite magnetic precession in an adjacent
ferromagnetic film. The flow of alternating current through a Pt/NiFe bilayer
generates an oscillating transverse spin current in the Pt, and the resultant
transfer of spin angular momentum to the NiFe induces ferromagnetic resonance
(FMR) dynamics. The Oersted field from the current also generates an FMR signal
but with a different symmetry. The ratio of these two signals allows a
quantitative determination of the spin current and the spin Hall angle.",1011.2788v1
2012-01-26,Inhomogeneous spin diffusion in traps with cold atoms,"The spin diffusion and damped oscillations are studied in the collision of
two spin polarized clouds of cold atoms with resonant interactions. The strong
density dependence of the diffusion coefficient leads to inhomogeneous spin
diffusion that changes from central to surface spin flow as the temperature
increases. The inhomogeneity and the smaller finite trap size significantly
reduce the spin diffusion rate at low temperatures. The resulting spin
diffusion rates, spin drag and initial damped oscillations are compatible with
measurements at low to high temperatures for resonant attractive interactions
but are incompatible with a metastable ferromagnetic phase.",1201.5526v2
2013-10-17,Electrically driven spin resonance in silicon carbide color centers,"We demonstrate that the spin of optically addressable point defects can be
coherently driven with AC electric fields. Based on magnetic-dipole forbidden
spin transitions, this scheme enables spatially confined spin control, the
imaging of high-frequency electric fields, and the characterization of defect
spin multiplicity. While we control defects in SiC, these methods apply to spin
systems in many semiconductors, including the nitrogen-vacancy center in
diamond. Electrically driven spin resonance offers a viable route towards
scalable quantum control of electron spins in a dense array.",1310.4844v1
2013-12-12,Microwave manipulation of electrically injected spin polarized electrons in silicon,"We demonstrate microwave manipulation of the spin states of electrically
injected spin-polarized electrons in silicon. Although the silicon channel is
bounded by ferromagnetic metal films, we show that moderate microwave power can
be applied to the devices without altering the device operation significantly.
Resonant microwave irradiation is used to induce spin rotation of
spin-polarized electrons as they travel across a silicon channel, and the
resultant spin polarization is subsequently detected by a ferromagnetic
Schottky barrier spin detector. These results demonstrate the potential for
combining advanced electron spin resonance techniques to complement the study
of semiconductor spintronic devices beyond standard magnetotransport
measurements.",1312.3663v1
2008-08-06,Electron spin resonance in Kondo systems,"We calculate the dynamical spin response of Kondo impurity and Kondo lattice
systems within a semiphenomenological Fermi liquid description, at low
temperatures $T<T_K$, the Kondo temperature, and low magnetic fields $B \ll k_B
T_K/g\mu_B$. Fermi liquid parameters are determined by comparison (i) with
microscopic theory (numerical renormalization group) for the impurity model and
(ii) with experiment for the lattice model. We find in the impurity case that
the true impurity spin resonance has a width of the order of $T_K$ and
disappears altogether if the $g$-factors of impurity spin and conduction
electron spin are equal. However, there is an impurity-induced resonance
contribution at the conduction electron resonance. The latter is broadened by
spin lattice relaxation and is usually unobservable. In contrast, for the
Anderson lattice in the Kondo regime we find a \textit{sharp} ESR resonance
line only slightly shifted from the local resonance and broadened by spin
lattice relaxation, the latter significantly reduced by both the effects of
heavy fermion physics and ferromagnetic fluctuations. We conjecture that our
findings explain the sharp ESR-lines recently observed in several heavy fermion
compounds.",0808.0892v2
2018-11-09,Microwave cavity detected spin blockade in a few electron double quantum dot,"We investigate spin states of few electrons in a double quantum dot by
coupling them weakly to a magnetic field resilient NbTiN microwave resonator.
We observe a reduced resonator transmission if resonator photons and spin
singlet states interact. This response vanishes in a magnetic field once the
quantum dot ground state changes from a spin singlet into a spin triplet state.
Based on this observation, we map the two-electron singlet-triplet crossover by
resonant spectroscopy. By measuring the resonator only, we observe Pauli spin
blockade known from transport experiments at finite source-drain bias and
detect an unconventional spin blockade triggered by the absorption of resonator
photons.",1811.03907v1
2018-07-25,Unusual suppression of a spin resonance mode with magnetic field in underdoped NaFe$_{1-x}$Co$_x$As: Evidence for orbital-selective pairing,"We use inelastic neutron scattering to study the fate of the two spin
resonance modes in underdoped superconducting NaFe$_{1-x}$Co$_x$As ($x=0.0175$)
under applied magnetic fields. While an applied in-plane magnetic field of
$B=12$ T only modestly suppresses superconductivity and enhances static
antiferromagnetic order, the two spin resonance modes display disparate
responses. The spin resonance mode at higher energy is mildly suppressed,
consistent with the field effect in other unconventional superconductors. The
spin resonance mode at lower energy, on the other hand, is almost completely
suppressed. Such dramatically different responses to applied magnetic field
indicate distinct origins of the two spin resonance modes, resulting from the
strongly orbital-selective nature of spin excitations and Cooper-pairing in
iron-based superconductors.",1807.09669v1
2023-07-18,"Propagation of Coupled Acoustic, Electromagnetic and Spin Waves in Saturated Ferromagnetoelastic Solids","We study the propagation of plane waves in an unbounded body of a saturated
ferromagnetoelastic solid. The equations by Tiersten for small fields
superposed on finite initial fields in a saturated ferromagnetoelastic material
are employed, with their quasistatic magnetic field extended to dynamic
electric and magnetic fields for electromagnetic waves. Dispersion relations of
the plane waves are obtained. The cutoff frequencies and long wave
approximation of the dispersion curves are determined. Results show that
acoustic, electromagnetic and magnetic spin waves are coupled in such a
material. For YIG which is a cubic crystal without piezoelectric coupling, the
acoustic and electromagnetic waves are not directly coupled but they can still
interact indirectly through spin waves.",2307.09171v1
2021-03-23,The Onset of Chaos in Permanently Deformed Binaries from Spin-Orbit and Spin-Spin Coupling,"Permanently deformed objects in binary systems can experience complex
rotation evolution, arising from the extensively studied effect of spin-orbit
coupling as well as more nuanced dynamics arising from spin-spin interactions.
The ability of an object to sustain an aspheroidal shape largely determines
whether or not it will exhibit non-trivial rotational behavior. In this work,
we adopt a simplified model of a gravitationally interacting primary and
satellite pair, where each body's quadrupole moment is approximated by two
diametrically opposed point masses. After calculating the net gravitational
torque on the satellite from the primary, and the associated equations of
motion, we employ a Hamiltonian formalism which allows for a perturbative
treatment of the spin-orbit and retrograde and prograde spin-spin coupling
states. By analyzing the resonances individually and collectively, we determine
the criteria for resonance overlap and the onset of chaos, as a function of
orbital and geometric properties of the binary. We extend the 2D planar
geometry to calculate the obliquity evolution, and find that satellites in
spin-spin resonances undergo precession when inclined out of the plane, but do
not tumble. We apply our resonance overlap criteria to the contact binary
system (216) Kleopatra, and find that its satellites, Cleoselene and
Alexhelios, may plausibly be exhibiting chaotic rotational dynamics from the
overlap of the spin-orbit and retrograde spin-spin resonances. While this model
is by construction generalizable to any binary system, it will be particularly
useful to study small bodies in the solar system, whose irregular shapes make
them ideal candidates for exotic rotational states.",2103.12484v1
2017-10-02,Qubit-assisted transduction for a detection of surface acoustic waves near the quantum limit,"We demonstrate ultra-sensitive measurement of fluctuations in a
surface-acoustic-wave~(SAW) resonator using a hybrid quantum system consisting
of the SAW resonator, a microwave (MW) resonator and a superconducting qubit.
The nonlinearity of the driven qubit induces parametric coupling, which
up-converts the excitation in the SAW resonator to that in the MW resonator.
Thermal fluctuations of the SAW resonator near the quantum limit are observed
in the noise spectroscopy in the MW domain.",1710.00467v1
2021-05-08,Strain effects on optical properties of linearly polarized resonant modes in the presence of monolayer graphene,"Recently, huge attention has been drawn to improve optical sensing devices
based on photonic resonators in the presence of graphene. In this paper, based
on the transfer matrix approach and TE polarization for the incident
electromagnetic waves, we numerically evaluate the transmission and reflection
spectra for one-dimensional photonic resonators and surface plasmon resonances
with strained graphene, respectively. We proved that a relatively small strain
field in graphene can modulate linearly polarized resonant modes within the
photonic bandgap of the defective crystal. Moreover, we study the strain
effects on the surface plasmon resonances created by the evanescent wave
technique at the interference between a monolayer graphene and prism.",2105.03633v1
2001-10-16,Energy Scales in the Local Magnetic Excitation Spectrum of YBCO,"The wave-vector integrated dynamical spin susceptibility chi_{2D}(omega) of
YBCO cuprates is considered. chi_{2D} is calculated in the superconducting
state from a renormalized mean-field theory of the t-t'-J-model, based on the
slave-boson formulation. Besides the well-known 41 meV resonance a second, much
broader peak (`hump') appears in Im chi_{2D}. It is caused by particle-hole
excitations across the maximum gap Delta^0. In contrast to the resonance, which
moves to lower energies when the hole filling is reduced from optimal doping,
the position of this `hump' at approx. 2 Delta^0 stays almost unchanged. The
results are in reasonable agreement with inelastic neutron-scattering
experiments.",0110316v1
2003-10-10,Evidence for an incommensurate magnetic resonance in La(2-x)Sr(x)CuO(4),"We study the effect of a magnetic field (applied along the c-axis) on the
low-energy, incommensurate magnetic fluctuations in superconducting
La(1.82)Sr(0.18)CuO(4). The incommensurate peaks at 9 meV, which in zero-field
were previously shown to sharpen in q on cooling below T_c [T. E. Mason et al.,
Phys. Rev. Lett. 77, 1604 (1996)], are found to broaden in q when a field of 10
T is applied. The applied field also causes scattered intensity to shift into
the spin gap. We point out that the response at 9 meV, though occurring at
incommensurate wave vectors, is comparable to the commensurate magnetic
resonance observed at higher energies in other cuprate superconductors.",0310231v1
1998-04-08,All-sky search algorithms for monochromatic signals in resonant bar GW detector data,"In this paper we design and develop several filtering strategies for the
analysis of data generated by a resonant bar Gravitational Wave (GW) antenna,
with the goal to assess the presence (or absence) in them of long duration
monochromatic GW signals, as well as their eventual amplitude and frequency,
within the sensitivity band of the detector. Such signals are most likely
generated in the fast rotation of slightly asymmetric spinning stars. We shall
develop the practical procedures, together with the study of their statistical
properties, which will provide us with useful information on each technique's
performance. The selection of candidate events will then be established
according to threshold-crossing probabilities, based on the Neyman-Pearson
criterion. In particular, it will be shown that our approach, based on phase
estimation, presents better signal-to-noise ratio than the most common one of
pure spectral analysis.",9804026v2
2004-04-20,Magnetic resonance in an elliptic magnetic field,"The behaviour of a particle with a spin 1/2 and a dipole magnetic moment in a
time-varying magnetic field in the form $(h_0 cn(\omega t,k), h_0 sn(\omega
t,k), H_0 dn(\omega t,k))$, where $\omega$ is the driving field frequency, $t$
is the time, $h_0$ and $H_0$ are the field amplitudes, $cn$, $sn$, $dn$ are
Jacobi elliptic functions, $ k$ is the modulus of the elliptic functions has
been considered. The variation parameter $k$ from zero to 1 gives rise to a
wide set of functions from trigonometric shapes to exponential pulse shapes
modulating the field. The problem was reduced to the solution of general Heun'
equation. The exact solution of the wave function was found at resonance for
any $ k$. It has been shown that the transition probability in this case does
not depend on $k$. The present study may be useful for analysis interference
experiments, improving magnetic spectrometers and the field of quantum
computing.",0404114v1
2006-11-15,Coherent control of photon transmission : slowing light in coupled resonator waveguide doped with $Λ$ Atoms,"In this paper, we propose and study a hybrid mechanism for coherent
transmission of photons in the coupled resonator optical waveguide (CROW) by
incorporating the electromagnetically induced transparency (EIT) effect into
the controllable band gap structure of the CROW. Here, the configuration setup
of system consists of a CROW with homogeneous couplings and the artificial
atoms with $\Lambda$-type three levels doped in each cavity. The roles of three
levels are completely considered based on a mean field approach where the
collection of three-level atoms collectively behave as two-mode spin waves. We
show that the dynamics of low excitations of atomic ensemble can be effectively
described by an coupling boson model. The exactly solutions show that the light
pulses can be stopped and stored coherently by adiabatically controlling the
classical field.",0611159v5
2007-10-25,"Hypernuclear production by ($γ, K^+$) reaction within a relativistic model","Within a fully covariant model based on an effective Lagrangian picture, we
investigate the hypernuclear production in photon-nucleus interaction on $
^{16}$O target. The explicit kaon production vertex is described via creation,
propagation and decay into relevant channel of $N^*$(1650), $N^*$(1710), and
$N^*$(1720) intermediate baryonic resonance states in the initial interaction
of the incident photon with one of the target protons. Bound state nucleon and
hyperon wave functions are obtained by solving the Dirac equation. Using vertex
parameters determined in the previous studies, contributions of the $N^*$(1710)
baryonic resonance dominate the total production cross sections which are found
to peak at photon energies below 1 GeV. The results show that photoproduction
is the most appropriate means for studying the unnatural parity hypernuclear
states, thus accessing the spin dependence of the hyperon-nucleon interaction.",0710.4888v2
2007-11-12,An x-ray resonant diffraction study of multiferroic DyMn2O5,"X-ray resonant scattering has been used to measure the magnetic order of the
Dy ions below 40K in multiferroic DyMn$_{2}$O$_{5}$. The magnetic order has a
complex behaviour. There are several different ordering wavevectors, both
incommensurate and commensurate, as the temperature is varied. In addition a
non-magnetic signal at twice the wavevector of one of the commensurate signals
is observed, the maximum intensity of which occurs at the same temperature as a
local maximum in the ferroelectric polarisation. Some of the results, which
bear resemblence to the behaviour of other members of the RMn$_{2}$O$_{5}$
family of multiferroic materials, may be explained by a theory based on
so-called acentric spin-density waves.",0711.1745v1
2008-05-28,Charge order in La_{1.8-x}Eu_{0.2}Sr_xCuO_4 studied by resonant soft X-ray diffraction,"Resonant soft X-ray scattering with photon energies near the O K and the Cu
L3 edges was used to study charge ordering in the system
La_{1.8-x}Eu_{0.2}Sr_xCuO_4 as a function of temperature for x = 0.125 and
0.15. From the superstructure diffraction intensities a charge ordering with a
doping dependent wave vector is derived which is in this system well below the
transition temperature of the low-temperature tetragonal phase but well above
the onset of spin ordering. This indicates that charge ordering is the primary
driving force for the formation of stripe-like phases in two-dimensional doped
cuprates. Analysis of the lineshape of the scattered intensity as a function of
photon energy yields evidence for a high hole concentration in the stripes.",0805.4352v1
2009-06-08,EuFe_2As_2 magnetic structure determination,"Magnetic resonant X ray scattering experiments have been performed on a
single crystal of EuFe_2As_2 at the Eu L_3 absorption edge. This has permitted
us to determine for the first time the orientation of Eu magnetic moments in
the antiferromagnetic ordered phase below T_N=19 K as parallel to the a-axis.
In addition, non-resonant magnetic X ray measurements indicate that Fe magnetic
moments align along the same direction in the spin density wave phase
(T<T_S~190 K). Temperature dependences indicate that the onset of the Eu AFM
phase barely affects the Fe magnetic sublattice.",0906.1508v3
2009-11-24,Incommensurate itinerant antiferromagnetic excitations and spin resonance in the FeTe$_{0.6}$Se$_{0.4}$ superconductor,"We report on inelastic neutron scattering measurements that find
incommensurate itinerant like magnetic excitations in the normal state of
superconducting FeTe$_{0.6}$Se$_{0.4}$ (\Tc=14K) at wave-vector
$\mathbf{Q}_{inc}=(1/2\pm\epsilon,1/2\mp\epsilon)$ with $\epsilon$=0.09(1). In
the superconducting state only the lower energy part of the spectrum shows
significant changes by the formation of a gap and a magnetic resonance that
follows the dispersion of the normal state excitations. We use a four band
model to describe the Fermi surface topology of iron-based superconductors with
the extended $s(\pm)$ symmetry and find that it qualitatively captures the
salient features of these data.",0911.4713v1
2010-01-27,Spherical model of the Stark effect in external scalar and vector fields,"The Bohr-Sommerfeld quantization rule and the Gamow formula for the width of
quasistationary level are generalized by taking into account the relativistic
effects, spin and Lorentz structure of interaction potentials. The relativistic
quasi-classical theory of ionization of the Coulomb system (V_{Coul}=-\xi/r) by
radial-constant long-range scalar (S_{l.r.}=(1-\lambda)(\sigma r+V_0)) and
vector (V_{l.r.}=\lambda(\sigma r+V_0)) fields is constructed. In the limiting
cases the approximated analytical expressions for the position E_r and width
\Gamma of below-barrier resonances are obtained. The strong dependence of the
width \Gamma of below-barrier resonances on both the bound level energy and the
mixing constant \lambda is detected. The simple analytical formulae for
asymptotic coefficients of the Dirac radial wave functions at zero and infinity
are also obtained.",1001.4948v1
2010-07-14,d-d Excitations in Bilayer Manganites Probed by Resonant Inelastic X-ray Scattering,"We report a high resolution resonant inelastic x-ray scattering investigation
of the bilayer manganites La$_{2-2x}$Sr$_{1+2x}$Mn$_2$O$_7$ with $x = 0.36$ and
$0.5$. The momentum dependence along the crystallographic $(110)$ direction for
energy losses $1\,\rm{eV} \leq \Delta E \leq 15\,\rm{eV}$ has been measured in
detail with the data analysis focusing on the energy loss region $1\,\rm{eV}
\leq \Delta E \leq 5\,\rm{eV}$, which includes a strong peak located at $\Delta
E \approx 2\,\rm{eV}$. We observe a clear dispersion of up to $0.5\,\rm{eV}$ in
the measured $\textbf{q}$ range, which is direct evidence of the non-local
character of this excitation. Further, we found that the intensity in this low
energy region strongly depends on both the reduced wave vector $\textbf{q} =
(h, h, 0)$, $h = 0.1 - 0.5$, and temperature, i.e. different ordered phases.
Results can be explained via an intersite $d-d$ charge transfer excitation,
proposed for pseudo-cubic manganites, where the hopping rate is strongly
increased (decreased) by ferromagnetic (antiferromagnetic) alignment of
neighboring in-plane Mn ion core spins.",1007.2283v1
2011-10-01,Electrical measurement of antivortex wall eigenfrequency,"The dynamics of a ferromagnetic antivortex wall has been experimentally
studied in a magnetic nanostructure. Two different techniques have been used to
independently measure the eigenfrequency of an antivortex wall such as the
resonance excitation by sinusoidal microwave and the damped resonance
excitation induced by short voltage pulses. Direct observation of antivortex
wall nucleation has been measured in the frequency domain for the first time.
Electrical measurements of the antivortex dynamics in frequency domain reveal
the existence of multi-eigenmodes as well as nonlinear behaviors for large
excitation amplitudes. The time resolved measurements of the antivortex wall
show that the frequency of the damped gyration is similar to that of frequency
domain and coexistence of spin wave excitations.",1110.0113v1
2011-11-23,Searching for the deformation-stability fundamental length (or fundamental time),"The existence of a fundamental length (or fundamental time) has been
conjectured in many contexts. However, the ""stability of physical theories
principle"" seems to be the one that provides, through the tools of algebraic
deformation theory, an unambiguous derivation of the stable structures that
Nature might have chosen for its algebraic framework. It is well-known that $c$
and $\hbar $ are the deformation parameters that stabilize the Galilean and the
Poisson algebra. When the stability principle is applied to the
Poincar\'{e}-Heisenberg algebra, two deformation parameters emerge which define
two length (or time) scales. In addition there are, for each of them, a plus or
minus sign possibility in the relevant commutators. One of the deformation
length scales, related to non-commutativity of momenta, is probably related to
the Planck length scale but the other might be much larger. In this paper this
is used as a working hypothesis to look for physical effects that might settle
this question. Phase-space modifications, deviations from $c$ in speed
measurements of massless wave packets, resonances, interference, electron spin
resonance and non-commutative QED are considered.",1111.5576v1
2012-11-29,"Coupled-channel dynamics in the reactions piN --> piN, etaN, KLambda, KSigma","Elastic piN scattering and the world data of the family of reactions pi^- p
--> eta n, K^0 Lambda$, K^0 Sigma^0, K^+ Sigma^-, and pi^+ p --> K^+ Sigma^+
are described simultaneously in an analytic, unitary, coupled-channel approach.
SU(3) flavor symmetry is used to relate both the t- and the u- channel
exchanges that drive the meson-baryon interaction in the different channels.
Angular distributions, polarizations, and spin-rotation parameters are compared
with available experimental data. Partial-wave amplitudes are determined and
the resonance content is extracted from the analytic continuation, including
resonance positions and branching ratios, and possible sources of uncertainties
are discussed. The results provide the final-state interactions for the ongoing
analysis of photo- and electroproduction data.",1211.6998v2
2012-12-12,Robust topological insulator surface conduction under strong surface disorder,"Topological insulators are characterized by specially protected conduction on
their outer boundaries. We show that the protected edge conduction exhibited by
2-D topological insulators (and also Chern insulators) is independent of
non-magnetic boundary disorder. In particular, the edge states residing inside
the bulk gap remain conducting even when edge state inhomogeneities destroy the
characteristic linear Dirac relation between energy and momentum. The main
effects of boundary disorder on the in-gap states are to decrease the Fermi
velocity, increase the density of states, pull the states into the disordered
region if spin is conserved, and at very large disorder shift the states to the
boundary between the disordered edge and the clean bulk. These effects, which
may be useful for device engineering, are controlled by a resonance between the
disordered edge and the bulk bands. The resonance's energy is set by the bulk
band width; protection of the in-gap edge states' plane-wave character is
controlled by the bulk band width, not the bulk band gap.",1212.2827v3
2013-05-07,Integer and Fractional Quantum Hall Effect in a Strip of Stripes,"We study anisotropic stripe models of interacting electrons in the presence
of magnetic fields in the quantum Hall regime with integer and fractional
filling factors. The model consists of an infinite strip of finite width that
contains periodically arranged stripes (forming supercells) to which the
electrons are confined and between which they can hop with associated magnetic
phases. The interacting electron system within the one-dimensional stripes are
described by Luttinger liquids and shown to give rise to charge and spin
density waves that lead to periodic structures within the stripe with a
reciprocal wavevector 8k_F. This wavevector gives rise to Umklapp scattering
and resonant scattering that results in gaps and chiral edge states at all
known integer and fractional filling factors \nu. The integer and odd
denominator filling factors arise for a uniform distribution of stripes,
whereas the even denominator filling factors arise for a non-uniform stripe
distribution. We calculate the Hall conductance via the Streda formula and show
that it is given by \sigma_H=\nu e^2/h for all filling factors. We show that
the composite fermion picture follows directly from the condition of the
resonant Umklapp scattering.",1305.1569v2
2013-12-10,Spectrum splitting of bimagnon excitations in a spatially frustrated Heisenberg antiferromagnet revealed by resonant inelastic x-ray scattering,"We perform a comprehensive analysis of the bimagnon resonant inelastic x-ray
scattering (RIXS) intensity spectra of the spatially frustrated Jx-Jy-J2
Heisenberg model on a square lattice in both the antiferromagnetic and the
collinear antiferromagnetic phase. We study the model for strong frustration
and significant spatial anisotropy to highlight the key signatures of RIXS
spectrum splitting which may be experimentally discernible. Based on an
interacting spin wave theory study within the ladder approximation
Bethe-Salpeter scheme, we find the appearance of a robust two-peak structure
over a wide range of the transferred momenta in both magnetically ordered
phases. The unfrustrated model has a single-peak structure with a two-peak
splitting originating due to spatial anisotropy and frustrated interactions.
Our predicted two-peak structure from both magnetically ordered regime can be
realized in iron pnictides.",1312.2876v2
2013-12-20,Polarization Observables for Kaon Photoproduction from Polarized Protons,"The search for undiscovered excited states of the nucleon continues to be a
focus of experiments at Jefferson Lab.Recent LQCD calculations have confirmed
long-standing quark-model predictions of many more states than have so far been
identified.A large effort for the N-star program has been launched using the
CLAS detector to provide the database that will allow nearly model-independent
partial wave analyses to be carried out in the search for such states.
Polarization observables play a crucial role in this effort, as they are
essential in disentangling overlapping resonant and non-resonant amplitudes. In
2010, double-polarization data were taken at JLab using circularly polarized
photons incident on a transversely polarized frozen-spin butanol target. Our
current analysis yields preliminary data of the T and F asymmetries for kaon
photoproduction final states, which are compared to predictions of recent
multipole analyses. This work is the first of its kind and will significantly
broaden the world database for these reactions.",1312.5804v1
2015-02-05,Quantum critical behavior in heavily doped LaFeAsO$_{1-x}$H$_x$ pnictide superconductors analyzed using nuclear magnetic resonance,"We studied the quantum critical behavior of the second antiferromagnetic (AF)
phase in the heavily electron-doped high-$T_c$ pnictide, LaFeAsO$_{1-x}$H$_x$
by using $^{75}$As and $^{1}$H nuclear-magnetic-resonance (NMR) technique. In
the second AF phase, we observed a spatially modulated spin-density-wave-like
state up to $x$=0.6 from the NMR spectral lineshape and detected a low-energy
excitation gap from the nuclear relaxation time $T_1$ of $^{75}$As. The
excitation gap closes at the AF quantum critical point (QCP) at $x \approx
0.49$. The superconducting (SC) phase in a lower-doping regime contacts the
second AF phase only at the AF QCP, and both phases are segregated from each
other. The absence of AF critical fluctuations and the enhancement of the
in-plane electric anisotropy are key factors for the development of
superconductivity.",1502.01467v1
2015-07-18,Phase-stable free-space optical lattices for trapped ions,"We demonstrate control of the absolute phase of an optical lattice with
respect to a single trapped ion. The lattice is generated by off-resonant
free-space laser beams, we actively stabilize its phase by measuring its
ac-Stark shift on a trapped ion. The ion is localized within the standing wave
to better than 2\% of its period. The locked lattice allows us to apply
displacement operations via resonant optical forces with a controlled direction
in phase space. Moreover, we observe the lattice-induced phase evolution of
spin superposition states in order to analyze the relevant decoherence
mechanisms. Finally, we employ lattice-induced phase shifts for inferring the
variation of the ion position over 157~$\mu$m range along the trap axis at
accuracies of better than 6~nm.",1507.05207v1
2016-02-07,Storage and conversion of quantum-statistical properties of light in the resonant quantum memory on tripod atomic configuration,"We have considered theoretically the feasibility of the broadband quantum
memory based on the resonant tripod-type atomic configuration. In this case,
the writing of a signal field is carried out simultaneously into two channels,
and characterized by an excitation of two spin waves of the atomic ensemble.
With simultaneous read out from both channels quantum properties of the
original signal are mapped on the retrieval pulse no worse than in the case of
memory based on Lambda-type atomic configuration. At the same time new
possibilities are opened up for manipulation of quantum states associated with
sequential reading out (and/or sequential writing) of signal pulses. For
example, the pulse in squeezed state is converted into two partially entangled
pulses with partially squeezed quadratures. Alternatively, two independent
signal pulses with orthogonal squeezed quadratures can be converted into two
entangled pulses.",1602.02364v1
2016-04-25,Quantitative determination of bond order and lattice distortions in nickel oxide heterostructures by resonant x-ray scattering,"We present a combined study of Ni $K$-edge resonant x-ray scattering and
density functional calculations to probe and distinguish electronically driven
ordering and lattice distortions in nickelate heterostructures. We demonstrate
that due to the low crystal symmetry, contributions from structural distortions
can contribute significantly to the energy-dependent Bragg peak intensities of
a bond-ordered NdNiO$_3$ reference film. For a LaNiO$_3$-LaAlO$_3$ superlattice
that exhibits magnetic order, we establish a rigorous upper bound on the
bond-order parameter. We thus conclusively confirm predictions of a dominant
spin density wave order parameter in metallic nickelates with a
quasi-two-dimensional electronic structure.",1604.07317v1
2016-05-10,Theoretical approach to direct resonant inelastic x-ray scattering on magnets and superconductors,"The capability to probe the dispersion of elementary spin, charge, orbital,
and lattice excitations has positioned resonant inelastic x-ray scattering
(RIXS) at the forefront of photon science. In this work, we will investigate
how RIXS can contribute to a deeper understanding of the orbital properties and
of the pairing mechanism in unconventional high-temperature superconductors. In
particular, we will show how direct RIXS spectra of magnetic excitations can
reveal long-range orbital correlations in transition metal compounds, by
discriminating different kind of orbital order in magnetic and
antiferromagnetic systems. Moreover, we will show how RIXS spectra of
quasiparticle excitations in superconductors can measure the superconducting
gap magnitude, and reveal the presence of nodal points and phase differences of
the superconducting order parameter on the Fermi surface. This can reveal the
properties of the underlying pairing mechanism in unconventional
superconductors, in particular cuprates and iron pnictides, discriminating
between different superconducting order parameter symmetries, such as $s$, $d$
(singlet pairing) and $p$ wave (triplet pairing).",1605.03189v1
2017-07-21,Modeling alignment enhancement for solid polarized targets,"A model of dynamic orientation using optimized radiofrequency (RF)
irradiation produced perpendicular to the holding field is developed for the
spin-1 system required for tensor-polarized fixed-target experiments. The
derivation applies to RF produced close to the Larmor frequency of the nucleus
and requires the electron spin-resonance linewidth to be much smaller than the
nuclear magnetic resonance frequency. The rate equations are solved numerically
to study a semi-saturated steady-state resulting from the two sources of
irradiation: microwave from the DNP process and the additional RF used to
manipulate the tensor polarization. The steady-state condition and
continuous-wave NMR lineshape are found that optimize the spin-1 alignment in
the polycrystalline materials used as solid polarized targets in charged-beam
nuclear and particle physics experiments.",1707.07065v1
2017-08-31,Soft Quantum Control for Highly Selective Interactions among Joint Quantum Systems,"We propose a quantum control scheme aimed at interacting systems that gives
rise to highly selective coupling among their near-to-resonance constituents.
Our protocol implements temporal control of the interaction strength, switching
it on and off again adiabatically. This soft temporal modulation significantly
suppresses off-resonant contributions in the interactions. Among the
applications of our method we show that it allows us to perform an efficient
rotating-wave approximation in a wide parameter regime, the elimination of side
peaks in quantum sensing experiments, and selective high-fidelity entanglement
gates on nuclear spins with close frequencies. We apply our theory to
nitrogen-vacancy centers in diamond and demonstrate the possibility for the
detection of weak electron-nuclear coupling under the presence of strong
perturbations.",1708.09611v2
2017-12-07,What is the right formalism to search for resonances?,"Hadron decay chains constitute one of the main sources of information on the
QCD spectrum. We discuss the differences between several partial wave analysis
formalisms used in the literature to build the amplitudes. We match the
helicity amplitudes to the covariant tensor basis. Hereby, we pay attention to
the analytical properties of the amplitudes and separate singularities of
kinematical and dynamical nature. We study the analytical properties of the
spin-orbit (LS) formalism, and some of the covariant tensor approaches. In
particular, we explicitly build the amplitudes for the B -> psi pi K and B ->
Dbar pi pi decays, and show that the energy dependence of the covariant
approach is model dependent. We also show that the usual recursive construction
of covariant tensors explicitly violates crossing symmetry, which would lead to
different resonance parameters extracted from scattering and decay processes.",1712.02815v1
2017-12-20,"Strong evidence for nucleon resonances near 1900\,MeV","Data on the reaction $\gamma p\to K^+\Lambda$ from the CLAS experiments are
used to derive the leading multipoles, $E_{0+}$, $M_{1-}$, $E_{1+}$, and
$M_{1+}$, from the production threshold to 2180\,MeV in 24 slices of the
invariant mass. The four multipoles are determined without any constraints. The
multipoles are fitted using a multichannel $L+P$ model which allows us to
search for singularities and to extract the positions of poles on the complex
energy plane in an almost model-independent method. The multipoles are also
used as additional constraints in an energy-dependent analysis of a large body
of pion and photo-induced reactions within the Bonn-Gatchina (BnGa) partial
wave analysis. The study confirms the existence of poles due to nucleon
resonances with spin-parity $J^P = 1/2^-; 1/2^+$, and $3/2^+$ in the region at
about 1.9\,GeV.",1712.07549v1
2018-01-24,Experimental Realization of Acoustic Chern Insulator,"Topological insulators are new states of matter in which the topological
phase originates from symmetry breaking. Recently, time-reversal invariant
topological insulators were demonstrated for classical wave systems, such as
acoustic systems, but limited by inter-pseudo-spin or inter-valley
backscattering. This challenge can be effectively overcome via breaking the
time-reversal symmetry. Here, we report the first experimental realization of
acoustic topological insulators with nonzero Chern numbers, viz., acoustic
Chern insulator (ACI), by introducing an angular-momentum-biased resonator
array with broken Lorentz reciprocity. High Q-factor resonance is leveraged to
reduce the required speed of rotation. Experimental results show that the ACI
featured with a stable and uniform metafluid flow bias supports one-way
nonreciprocal transport of sound at the boundaries, which is topologically
immune to the defect-induced scatterings. Our work opens up opportunities for
exploring unique observable topological phases and developing practical
nonreciprocal devices in acoustics.",1801.07942v1
2018-12-23,Fermion Clouds Around $z=0$ Lifshitz Black Holes,"The Dirac equation is solved in the $z=0$ Lifshitz black hole ($Z0$LBH)
spacetime. The set of equations representing the Dirac equation in the
Newman-Penrose (NP) formalism is decoupled into a radial set and an angular
set. The separation constant is obtained with the aid of the spin weighted
spheroidal harmonics. The radial set of equations, which is independent of
mass, is reduced to Zerilli equations (ZEs)\ with their associated potentials.
In the near horizon (NH) region, these equations solved in terms of the Bessel
functions of the first and second kinds arising from the fermionic perturbation
on the background geometry. For computing the BQNMs instead of the ordinary
quasinormal modes (QNMs), we first impose the purely ingoing wave condition at
the event horizon. And then, Dirichlet boundary condition (DBC) and Newmann
boundary condition (NBC) are applied in order to get the resonance conditions.
For solving the resonance conditions we follow an iteration method. Finally,
Maggiore's method (MM) is employed to derive the entropy/area spectra of the
$Z0$LBH which are shown to be equidistant.",1812.09711v1
2019-02-01,Collective magnetization dynamics in nano-arrays of thin FePd discs,"We report on the magnetization dynamics of a square array of mesoscopic
discs, fabricated from an iron palladium alloy film. The dynamics properties
were explored using ferromagnetic resonance measurements and micromagnetic
simulations. The obtained spectra exhibit features resulting from the
interactions between the discs, with a clear dependence on both temperature and
the direction of the externally applied field. We demonstrate a qualitative
agreement between the measured and calculated spectra. Furthermore, we
calculated the mode profiles of the standing spin waves excited during a
time-dependent magnetic field excitations. The resulting maps confirm that the
features appearing in the ferromagnetic resonance absorption spectra originate
from the temperature and directional dependent inter-disc interactions.",1902.00403v1
2020-08-10,Optical signatures of charge order in a Mott-Wigner state,"The elementary optical excitations in two dimensional semiconductors hosting
itinerant electrons are attractive and repulsive polarons -- excitons that are
dynamically screened by electrons. Exciton-polarons have hitherto been studied
in translationally invariant degenerate Fermi systems. Here, we show that
electronic charge order breaks the excitonic translational invariance and leads
to a direct optical signature in the exciton-polaron spectrum. Specifically, we
demonstrate that new optical resonances appear due to spatially modulated
interaction between excitons and electrons in an incompressible Mott state. Our
observations demonstrate that resonant optical spectroscopy provides an
invaluable tool for studying strongly correlated states, such as Wigner
crystals and density waves, where exciton-electron interactions are modified by
the emergence of new electronic charge or spin order.",2008.04156v2
2020-03-19,Nonlinear wavefront control by geometric-phase dielectric metasurfaces: Influence of mode field and rotational symmetry,"Nonlinear Pancharatnam-Berry phase metasurfaces facilitate the nontrivial
phase modulation for frequency conversion processes by leveraging photon-spin
dependent nonlinear geometric-phases. However, plasmonic metasurfaces show some
severe limitation for nonlinear frequency conversion due to the intrinsic high
ohmic loss and low damage threshold of plasmonic nanostructures. Here, we
systematically study the nonlinear geometric-phases associated with the
third-harmonic generation process occurring in all-dielectric metasurfaces,
which are composed of silicon nanofins with different in-plane rotational
symmetries. We find that the wave coupling among different field components of
the resonant fundamental field gives rise to the appearance of different
nonlinear geometric-phases of the generated third-harmonic signals. The
experimental observations of the nonlinear beam steering and nonlinear
holography realized in this work by all-dielectric geometric-phase metasurfaces
are well explained with our developed theory. Our work offers a new physical
picture to understand the nonlinear optical process occurring at nanoscale
dielectric resonators and will help in the design of nonlinear metasurfaces
with tailored phase properties.",2003.08623v2
2020-11-16,Microwave spectroscopy of the low-temperature skyrmion state in Cu2OSeO3,"In the cubic chiral magnet Cu2OSeO3 a low-temperature skyrmion state (LTS)
and a concomitant tilted conical state are observed for magnetic fields
parallel to <100>. In this work, we report on the dynamic resonances of these
novel magnetic states. After promoting the nucleation of the LTS by means of
field cycling, we apply broadband microwave spectroscopy in two experimental
geometries that provide either predominantly in-plane or out-of-plane
excitation. By comparing the results to linear spin-wave theory, we clearly
identify resonant modes associated with the tilted conical state, the
gyrational and breathing modes associated with the LTS, as well as the
hybridization of the breathing mode with a dark octupole gyration mode mediated
by the magnetocrystalline anisotropies. Most intriguingly, our findings suggest
that under decreasing fields the hexagonal skyrmion lattice becomes unstable
with respect to an oblique deformation, reflected in the formation of elongated
skyrmions.",2011.07826v1
2021-08-07,Strong Momentum-Dependent Electron-Magnon Renormalization of a Surface Resonance on Iron,"The coupling of fermionic quasiparticles to magnons is essential for a wide
range of processes, from ultrafast magnetization dynamics in ferromagnets to
Cooper pairing in superconductors. Although magnon energies are generally much
larger than phonon energies, up to now their electronic band renormalization
effect in ferromagnetic metals suggests a significantly weaker quasiparticle
interaction. Here, using spin- and angle-resolved photoemission, we show an
extraordinarily strong renormalization leading to replica-band formation of an
iron surface resonance at ~200 meV. Its strong magnetic linear dichroism
unveils the magnetic nature and momentum dependence of the energy
renormalization. By determining the frequency- and momentum-dependent
self-energy due to generic electron-boson interaction to compute the resultant
electron spectral function, we show that the surface-state replica formation is
consistent with strong coupling to an optical spin wave in a Fe thin film.",2108.03421v1
2003-12-24,Semiquantitative theory of electronic Raman scattering from medium-size quantum dots,"A consistent semiquantitative theoretical analysis of electronic Raman
scattering from many-electron quantum dots under resonance excitation
conditions has been performed. The theory is based on
random-phase-approximation-like wave functions, with the Coulomb interactions
treated exactly, and hole valence-band mixing accounted for within the
Kohn-Luttinger Hamiltonian framework. The widths of intermediate and final
states in the scattering process, although treated phenomenologically, play a
significant role in the calculations, particularly for well above band gap
excitation. The calculated polarized and unpolarized Raman spectra reveal a
great complexity of features and details when the incident light energy is
swept from below, through, and above the quantum dot band gap. Incoming and
outgoing resonances dramatically modify the Raman intensities of the single
particle, charge density, and spin density excitations. The theoretical results
are presented in detail and discussed with regard to experimental observations.",0312636v1
2021-01-22,Optimising optical tweezers experiments for magnetic resonance sensing with nanodiamonds,"In this article we explore the requirements for enabling high quality
optically detected magnetic resonance (ODMR) spectroscopy in a conventional
gradient force optical tweezers using nanodiamonds containing nitrogen-vacancy
(NV$^{-}$) centres. We find that modulation of the infrared (1064 nm) trapping
laser during spectroscopic measurements substantially improves the ODMR
contrast compared with continuous wave trapping. The work is significant as it
allows trapping and quantum sensing protocols to be performed in conditions
where signal contrast is substantially reduced. We demonstrate the utility of
the technique by resolving NV$^{-}$ spin projections within the ODMR spectrum.
Manipulating the orientation of the nanodiamond via the trapping laser
polarisation, we observe changes in spectral features. Theoretical modelling
then allows us to infer the crystallographic orientation of the NV$^{-}$. This
is an essential capability for future magnetic sensing applications of
optically trapped nanodiamonds.",2101.08941v1
2021-06-08,Optical lattice for tripod-like atomic level structure,"Standard optical potentials use off-resonant laser standing wave induced
AC-Stark shift. In a recent development [Phys. Rev. Lett. {\bf 117}, 233001
(2016)] a three-level scheme in $\Lambda$ configuration coupled coherently by
resonant laser fields was introduced leading to an effective lattice with
subwavelength potential peaks. Here as an extension of that work to a four
level atomic setup in the tripod configuration is used to create spin
$1/2$-like two-dimensional dark-space with 1D motion and the presence of
external gauge fields. Most interestingly for a possible application, the
lifetime for a dark subspace motion is up to two orders of magnitude larger
than for a similar $\Lambda$ system. The model is quite flexible leading to
lattices with significant nearest, next-nearest, or next-next-nearest hopping
rates, $J_1,J_2,J_3$ opening up new intriguing possibilities to study, e.g.
frustrated systems. The characteristic Wannier functions lead also to new type
of inter-site interactions not realizable in typical optical lattices.",2106.04709v2
2021-07-02,"Plasma-photon interaction in curved spacetime II: collisions, thermal corrections, and superradiant instabilities","Motivated by electromagnetic-field confinement due to plasma near accreting
black holes, we continue our exploration of the linear dynamics of an
electromagnetic field propagating in curved spacetime in the presence of plasma
by including three effects that were neglected in our previous analysis:
collisions in the plasma, thermal corrections, and the angular momentum of the
background black-hole spacetime. We show that: (i) the plasma-driven long-lived
modes survive in a collisional plasma except when the collision timescale is
unrealistically small; (ii) thermal effects, which might be relevant for
accretion disks around black holes, do not affect the axial long-lived modes;
(iii) in the case of a spinning black hole the plasma-driven modes become
superradiantly unstable at the linear level; (iv) the polar sector in the
small-frequency regime admits a reflection point due to the resonant properties
of the plasma. Dissipative effects such as absorption, formation of plasma
waves, and nonlinear dynamics play a crucial role in the vicinity of this
resonant point.",2107.01174v1
2021-07-05,Collective spin and charge excitations in the $t$-$J$-$U$ model of high-$T_c$ cuprates,"The $t$-$J$-$U$ model of high-$T_c$ copper-oxide superconductors incorporates
both the on-site Coulomb repulsion and kinetic exchange interaction and yields
a semi-quantitative description of the static properties of those materials. We
extend this analysis to dynamic quantities and address collective spin- and
charge excitations in the correlated metallic state of the $t$-$J$-$U$ model.
We employ VWF+$1/\mathcal{N}_f$ approach that combines the variational wave
function (VWF) approach with the expansion in the inverse number of fermionic
flavors ($1/\mathcal{N}_f$). It is shown that the resonant (paramagnon)
contribution to the dynamic magnetic susceptibility remains robust as one
interpolates between the Hubbard- and $t$-$J$-model limits, whereas the
incoherent continuum undergoes substantial renormalization. Energy of the
collective charge mode diminishes as the strong-coupling limit is approached.
We also introduce the concept of effective kinetic exchange interaction that
allows for a unified interpretation of magnetic dynamics in the Hubbard,
$t$-$J$, and $t$-$J$-$U$ models. The results are discussed in the context of
recent resonant inelastic $x$-ray scattering experiments for the high-$T_c$
cuprates.",2107.02152v1
2021-07-21,Towards $\textit{ab initio}$ identification of paramagnetic substitutional carbon defects in hexagonal boron nitride acting as quantum bits,"Paramagnetic substitutional carbon (C$_\text{B}$, C$_\text{N}$) defects in
hexagonal boron nitride (hBN) are discussed as candidates for quantum bits.
Their identification and suitability are approached by means of
photoluminescence (PL), charge transitions, electron paramagnetic resonance,
and optically detected magnetic resonance (ODMR) spectra. Several clear trends
in these are revealed by means of an efficient plane wave periodic supercell
\textit{ab initio} density functional theory approach. In particular, this
yields insight into the role of the separation between C$_\text{B}$ and
C$_\text{N}$. In most of the cases the charge transition between the neutral
and a singly charged ground state of a defect is predicted to be experimentally
accessible, since the charge transition level (CTL) position lies within the
band gap. \textit{A posteriori} charge corrections are also discussed. A
near-identification of an experimentally isolated single spin center as the
neutral C$_\text{B}$ point defect was found via comparison of results to
recently observed PL and ODMR spectra.",2107.10366v1
2021-09-08,Control of reactive collisions by quantum interference,"In this study, we achieved magnetic control of reactive scattering in an
ultracold mixture of $^{23}$Na atoms and $^{23}$Na$^{6}$Li molecules. In most
molecular collisions, particles react or are lost near short range with unity
probability, leading to the so-called universal rate. By contrast, the
Na{+}NaLi system was shown to have only $\sim4\%$ loss probability in a fully
spin-polarized state. By controlling the phase of the scattering wave function
via a Feshbach resonance, we modified the loss rate by more than a factor of
$100$, from far below to far above the universal limit. The results are
explained in analogy with an optical Fabry-Perot resonator by interference of
reflections at short and long range. Our work demonstrates quantum control of
chemistry by magnetic fields with the full dynamic range predicted by our
models.",2109.03944v2
2021-09-28,Anionic Ordering in Pb$_2$Ti$_4$O$_9$F$_2$ Revisited by Nuclear Magnetic Resonance and Density Functional Theory,"A combination of $^{19}$F magic angle spinning (MAS) nuclear magnetic
resonance (NMR) and density functional theory (DFT) were used to study the
ordering of F atoms in Pb$_2$Ti$_4$O$_9$F$_2$. This analysis revealed that F
atoms predominantly occupy two of the six available inequivalent sites in a
ratio of 73:27. DFT-based calculations explained the preference of F occupation
on these sites and quantitatively reproduced the experimental occupation ratio,
independent of the choice of functional. We concluded that the Pb atom's 6$s^2$
lone pair may play a role ($\sim$0.1 eV/f.u.) in determining the majority and
minority F occupation sites with partial density of states and crystal orbital
Hamiltonian population analyses applied to the DFT wave functions.",2109.14098v3
2021-11-02,Chiral Magnonic Resonators: Rediscovering the Basic Magnetic Chirality in Magnonics,"The outlook for producing useful practical devices within the paradigm of
magnonics rests on our ability to emit, control and detect coherent exchange
spin waves on the nanoscale. Here, we argue that all these key functionalities
can be delivered by chiral magnonic resonators - soft magnetic elements
chirally coupled, via magneto-dipole interaction, to magnonic media nearby.
Starting from the basic principles of chiral coupling, we outline how they
could be used to construct devices and explore underpinning physics, ranging
from basic logic gates to field programmable gate arrays, in-memory computing,
and artificial neural networks, and extending from one- to two- and
three-dimensional architectures.",2111.01508v1
2021-12-06,Charge and spin order dichotomy in NdNiO$_2$ driven by SrTiO$_3$ capping layer,"Superconductivity in infinite-layer nickelates holds exciting analogies with
that of cuprates, with similar structures and $3d$-electron count. Using
resonant inelastic x-ray scattering (RIXS) we studied electronic and magnetic
excitations and charge density correlations in Nd$_{1-x}$Sr$_{x}$NiO$_2$ thin
films with and without an SrTiO$_3$ capping layer. We observe dispersing
magnons only in the capped samples, progressively dampened at higher doping. In
addition, we detect an elastic resonant scattering peak in the uncapped $x=0$
compound at wave vector (1/3,0), remindful of the charge order signal in hole
doped cuprates. The peak weakens at $x=0.05$ and disappears in the
superconducting $x=0.20$ film. The uncapped samples also present a higher
degree of Ni$3d$-Nd$5d$ hybridization and a smaller anisotropy of the Ni$3d$
occupation with respect to the capped samples. The role of the capping on the
possible hydrogen incorporation or on other mechanisms responsible for the
electronic reconstruction far from the interface remains to be understood.",2112.03341v1
2022-12-24,Directionality between driven-dissipative resonators,"The notion of nonreciprocity, in essence when going forwards is different
from going backwards, emerges in all branches of physics from cosmology to
electromagnetism. Intriguingly, the breakdown of reciprocity is typically
associated with extraordinary phenomena, which may be readily capitalized on in
the design of (for example) nontrivial electromagnetic devices when Lorentz
reciprocity is broken. However, in order to enable the exploitation of
nonreciprocal-like effects in the next generation of quantum technologies,
basic quantum optical theories are required. Here we present a versatile model
describing a pair of driven-dissipative quantum resonators, where the relative
phase difference between the coherent and incoherent couplings induces an
asymmetry. The interplay between the diverse dissipative landscape - which
encompasses both intrinsic losses and dissipative couplings - and the coherent
interactions leads to some remarkable consequences including highly directional
(or even one-way) energy transport. Our work proffers the tantalizing prospect
of observing dissipation-induced quantum directionality in areas like photonics
or cavity magnonics (spin waves), which may aid the design of unconventional
nanoscopic devices.",2212.12777v1
2023-01-09,Resonating holes vs molecular spin-orbit coupled states in group-5 lacunar spinels,"The valence electronic structure of magnetic centers is one of the factors
that determines the characteristics of a magnet. It may refer to orbital
degeneracy, as for $j_\text{eff}=1/2$ Kitaev magnets, or near-degeneracy, e.g.
involving the third and fourth shells in cuprate superconductors. Here we
explore the inner structure of magnetic moments in group-5 lacunar spinels,
fascinating materials featuring multisite magnetic units in the form of
tetrahedral tetramers. Our quantum chemical analysis reveals a very colorful
landscape, much richer than the single-electron, single-configuration
description applied so far to all group-5 Ga$M_4X_8$ chalcogenides, and
clarifies the basic multiorbital correlations on $M_4$ tetrahedral clusters:
while for V strong correlations yield a wave-function that can be well
described in terms of four V$^{4+}$V$^{3+}$V$^{3+}$V$^{3+}$ resonant valence
structures, for Nb and Ta a picture of dressed molecular-orbital-like
$j_\text{eff}=3/2$ entities is more appropriate. These internal degrees of
freedom likely shape vibronic couplings, phase transitions, and
magneto-electric properties in each of these systems.",2301.03392v3
2023-02-21,Maser Threshold Characterization by Resonator Q-Factor Tuning,"Whereas the laser is nowadays an ubiquitous technology, applications for its
microwave analogue, the maser, remain highly specialized, despite the excellent
low-noise microwave amplification properties. The widespread application of
masers is typically limited by the need of cryogenic temperatures. The recent
realization of a continuous-wave room-temperature maser, using NV$^-$ centers
in diamond, is a first step towards establishing the maser as a potential
platform for microwave research and development, yet its design is far from
optimal. Here, we design and construct an optimized setup able to characterize
the operating space of a maser using NV$^-$ centers. We focus on the interplay
of two key parameters for emission of microwave photons: the quality factor of
the microwave resonator and the degree of spin level-inversion. We characterize
the performance of the maser as a function of these two parameters, identifying
the parameter space of operation and highlighting the requirements for maximal
continuous microwave emission.",2302.10811v2
2002-02-14,Dilepton decays of baryon resonances,"Dalitz decay of baryon resonances is studied and expressions for the decay
width are derived for resonances with arbitrary spin and parity. Contributions
of the various terms in the transition matrix element are compared and
relevance of spin-parity and the resonance mass is discussed. Explicite
algebraic expressions are cited for spin$\le$5/2 resonances. The results can be
used in models of dielectron production in elementary reactions and heavy ion
collisions.",0202047v1
2008-12-14,"Magnetic resonance in the cuprates -- exciton, plasmon, or π-mode","We re-analyzed the issue whether the resonance peak observed in neutron
scattering experiments on the cuprates is an exciton, a \pi-resonance, or a
magnetic plasmon. We considered a toy model with on-cite Hubbard U and
nearest-neighbor interactions in both charge and spin channels. We found that
the resonance is predominantly an exciton, even if magnetic interaction is
absent and d-wave pairing originates from attractive density-density
interaction. Our results indicate that one cannot distinguish between spin and
charge-mediated pairing interactions by just looking at the resonance peak in
the dynamic spin susceptibility.",0812.2697v1
2022-06-21,Emergent s-wave interactions between identical fermions in quasi-one-dimensional geometries,"Orbital degrees of freedom play an essential role in metals, semiconductors,
and strongly confined electronic systems. Experiments with ultracold atoms have
used highly anisotropic confinement to explore low-dimensional physics, but
typically eliminate orbital degrees of freedom by preparing motional ground
states in strongly confined directions. Here we prepare multi-band systems of
spin-polarized fermionic potassium ($^{40}$K) in the quasi-one-dimensional
(q1D) regime and quantify the strength of atom-atom correlations using
radio-frequency spectroscopy. The activation of orbital degrees of freedom
leads to a new phenomenon: a low-energy scattering channel that has even
particle-exchange parity along the q1D axis, as if the underlying interactions
were s-wave. This emergent exchange symmetry is enabled by orbital singlet wave
functions in the strongly confined directions, which also confer high-momentum
components to low-energy q1D collisions. We measure both the q1D odd-wave and
even-wave ""contact"" parameters for the first time, and compare them to
theoretical predictions of one-dimensional many-body models. The strength and
spatial symmetry of interactions are tuned by a p-wave Feshbach resonance and
by transverse confinement strength. Near resonance, the even-wave contact
approaches its theoretical unitary value, whereas the maximum observed odd-wave
contact remains several orders of magnitude below its unitary limit. Low-energy
scattering channels of multi-orbital systems, such as those found here, may
provide new routes for the exploration of universal many-body phenomena.",2206.10415v2
2009-09-17,Edge spin accumulation: spin Hall effect without bulk spin current,"Spin accumulation in a 2D electron gas with Rashba spin-orbit interaction
subject to an electric field can take place without bulk spin currents (edge
spin Hall effect). This is demonstrated for the collisional regime using the
non-equilibrium distribution function determined from the standard Boltzmann
equation. Spin accumulation originates from interference of incident and
reflected electron waves at the sample boundary.",0909.3156v1
2018-11-03,Tunable Spin Seebeck Diode with Magnonic Spin Tunneling Junction,"We theoretically investigate the spin--wave spin current induced by the spin
Seebeck effect in magnonic spin tunneling junctions (MSTJs) for arbitrary
magnetization directions. We show that the MSTJ functions as a \textit{tunable}
spin Seebeck diode in which the tunneling spin current can be turned on and off
with high efficiency by controlling the magnetization direction.",1811.01141v1
2021-02-24,Enhancement of wave transmissions in multiple radiative and convective zones,"In this paper, we study wave transmission in a rotating fluid with multiple
alternating convectively stable and unstable layers. We have discussed wave
transmissions in two different circumstances: cases where the wave is
propagative in each layer and cases where wave tunneling occurs. We find that
efficient wave transmission can be achieved by `resonant propagation' or
`resonant tunneling', even when stable layers are strongly stratified, and we
call this phenomenon `enhanced wave transmission'. Enhanced wave transmission
only occurs when the total number of layers is odd (embedding stable layers are
alternatingly embedded within clamping convective layers, or vise versa). For
wave propagation, the occurrence of enhanced wave transmission requires that
clamping layers have similar properties, the thickness of each clamping layer
is close to a multiple of the half wavelength of the corresponding propagative
wave, and the total thickness of embedded layers is close to a multiple of the
half wavelength of the corresponding propagating wave (resonant propagation).
For wave tunneling, we have considered two cases: tunneling of gravity waves
and tunneling of inertial waves. In both cases, efficient tunneling requires
that clamping layers have similar properties, the thickness of each embedded
layer is much smaller than the corresponding e-folding decay distance, and the
thickness of each clamping layer is close to a multiple-and-a-half of half
wavelength (resonant tunneling).",2102.12018v1
2010-07-27,Oscillating magnetic induction defined by neutron reflection,"The expressions are received for neutron reflection from the wave resonator
placed in an oscillating magnetic field. The conditions are defined for optimal
values of the neutron wave resonator and magnetic field parameters. Numerical
calculations which support theory conclusions are carried out for real systems.",1007.4666v1
2017-11-19,SU($N$) spin-wave theory: Application to spin-orbital Mott insulators,"We present the application of the SU($N$) ($N>2$) spin-wave theory to
spin-orbital Mott insulators whose ground states exhibit magnetic orders. When
taking both the spin and orbital degrees of freedom into account rather than
projecting onto the Kramers doublet, the lowest spin-orbital locking energy
levels, due to the inevitable spin-orbital multipole exchange interactions, the
SU($N$) spin-wave theory should take the place of the SU($2$) one. To implement
the application, we introduce an efficient general local mean field approach
which involves all the local fluctuations into the SU($N$) linear spin-wave
theory. Our approach is tested firstly by calculating the multipolar spin-wave
spectra of the SU($4$) antiferromagnetic model. Then we apply it to
spin-orbital Mott insulators. It is revealed that the Hund's coupling would
influence the effectiveness of the isospin-$1/2$ representation when the spin
orbital coupling is not large enough. Besides, we also calculate the spin-wave
spectra based on the first principle calculations for two concrete materials,
$\alpha$-RuCl$_3$ and Sr$_2$IrO$_4$. The SU($N$) spin-wave theory appropriately
depicts the low-energy magnons and the spin-orbital excitations qualitatively.",1711.07041v1
2010-06-12,Resonant Absorption of Fast Magnetoacoustic Waves due to Coupling into the Slow and Alfven Continua in the Solar Atmosphere,"Resonant absorption of fast magnetoacoustic (FMA) waves in an inhomogeneous,
weakly dissipative, one-dimensional planar, strongly anisotropic and dispersive
plasma is investigated. The magnetic configuration consists of an inhomogeneous
magnetic slab sandwiched between two regions of semi-infinite homogeneous
magnetic plasmas. Laterally driven FMA waves penetrate the inhomogeneous slab
interacting with the localised slow or Alfven waves present in the
inhomogeneous layer and are partly reflected, dissipated and transmitted by
this region. The presented research aims to find the coefficient of wave energy
absorption under solar chromospheric and coronal conditions. Numerical results
are analyzed to find the coefficient of wave energy absorption at both the slow
and Alfven resonance positions. The mathematical derivations are based on the
two simplifying assumptions that (i) nonlinearity is weak, and (ii) the
thickness of the inhomogeneous layer is small in comparison to the wavelength
of the wave, i.e. we employ the so-called long wavelength approximation. Slow
resonance is found to be described by the nonlinear theory, while the dynamics
at the Alfven resonance can be described within the linear framework. We
introduce a new concept of coupled resonances, which occurs when two different
resonances are in close proximity to each other, causing the incoming wave to
act as though it has been influenced by the two resonances simultaneously. Our
results show that the wave energy absorption is heavily dependent on the angle
of the incident wave in combination with the inclination angle of the
equilibrium magnetic field. In addition, it is found that FMA waves are very
efficiently absorbed at the Alfven resonance under coronal conditions. Under
chromospheric conditions the FMA waves are far less efficiently absorbed,
despite an increase in efficiency due to the coupled resonances.",1006.2427v1
2010-09-22,Phosphorus Spin Coherence Times in Silicon at Very Low Temperatures,"Phosphorus donor spin coherence in isotopically pure 28 silicon is measured
at very low temperatures using pulsed electron spin resonance. The isolated
spin T2 varies unexpectedly with phosphorus concentration",1009.4240v1
2013-10-14,Ballistic spin resonance in multisubband quantum wires,"Ballistic spin resonance was experimentally observed in a
quasi-one-dimensional wire by Frolov et al. [Nature (London) 458, 868 (2009)].
The spin resonance was generated by a combination of an external static
magnetic field and the oscillating effective spin-orbit magnetic field due to
periodic bouncings of the electrons off the boundaries of a narrow channel. An
increase of the D'yakonov-Perel spin relaxation rate was observed when the
frequency of the spin-orbit field matched that of the Larmor precession
frequency around the external magnetic field. Here we develop a model to
account for the D'yakonov-Perel mechanism in multisubband quantum wires with
both the Rashba and Dresselhaus spin-orbit interactions. Considering elastic
spin-conserving impurity scatterings in the time-evolution operator (Heisenberg
representation), we extract the spin relaxation time by evaluating the
time-dependent average of the spin operators. The magnetic field dependence of
the nonlocal voltage, which is related to the spin relaxation time behavior,
shows a wide plateau, in agreement with the experimental observation. This
plateau arises due to injection in higher subbands and small-angle scattering.
In this quantum mechanical approach, the spin resonance occurs near the
spin-orbit induced energy anticrossings of the quantum wire subbands with
opposite spins. We also predict anomalous dips in the spin relaxation time as a
function of the magnetic field in systems with strong spin-orbit couplings.",1310.3707v2
2021-03-10,Probing optical spin-currents using THz spin-waves in noncollinear magnetic bilayers,"Optically induced spin currents have proven to be useful in spintronics
applications, allowing for sub-ps all-optical control of magnetization.
However, the mechanism responsible for their generation is still heavily
debated. Here we use the excitation of spin-current induced THz spin-waves in
noncollinear bilayer structures to directly study optical spin-currents in the
time domain. We measure a significant laser-fluence dependence of the spin-wave
phase, which can quantitatively be explained assuming the spin current is
proportional to the time derivative of the magnetization. Measurements of the
absolute spin-wave phase, supported by theoretical calculations and
micromagnetic simulations, suggest that a simple ballistic transport picture is
sufficient to properly explain spin transport in our experiments and that the
damping-like optical STT dominates THz spin-wave generation. Our findings
suggest laser-induced demagnetization and spin-current generation share the
same microscopic origin.",2103.06029v1
2003-05-06,Resonant spin-flavor conversion of supernova neutrinos: Dependence on presupernova models and future prospects,"We study the resonant spin-flavor (RSF) conversion of supernova neutrinos,
which is induced by the interaction between the nonzero neutrino magnetic
moment and the supernova magnetic fields, and its dependence on presupernova
models. As the presupernova models, we adopt the latest ones by Woosley, Heger,
and Weaver, and, further, models with both solar and zero metallicity are
investigated. Since the $(1-2Y_e)$ profile of the new presupernova models,
which is responsible for the RSF conversion, suddenly drops at the resonance
region, the completely adiabatic RSF conversion is not realized, even if
$\mu_\nu B_0= (10^{-12}\mu_B)(10^{10} G)$, where $B_0$ is the strength of the
magnetic field at the surface of the iron core. In particular for the model
with zero metallicity, the conversion is highly nonadiabatic in the high energy
region, reflecting the $(1-2Y_e)$ profile of the model. In calculating the
flavor conversion, we find that the shock wave propagation, which changes
density profiles drastically, is a much more severe problem than it is for the
pure Mikheyev-Smirnov-Wolfenstein (MSW) conversion case. This is because the
RSF effect occurs at a far deeper region than the MSW effect. To avoid the
uncertainty concerning the shock propagation, we restrict our discussion to 0.5
s after the core bounce (and for more conservative discussion, 0.25 s), during
which the shock wave is not expected to affect the RSF region. We also evaluate
the energy spectrum at the Super-Kamiokande detector for various models using
the calculated conversion probabilities, and find that it is very difficult to
obtain useful information on the supernova metallicities and magnetic fields or
on the neutrino magnetic moment from the supernova neutrino observation. Future
prospects are also discussed.",0305052v2
2010-01-26,Spin-wave instabilities in spin-transfer-driven magnetization dynamics,"We study the stability of magnetization precessions induced in spin-transfer
devices by the injection of spin-polarized electric currents. Instability
conditions are derived by introducing a generalized, far-from-equilibrium
interpretation of spin-waves. It is shown that instabilities are generated by
distinct groups of magnetostatically coupled spin-waves. Stability diagrams are
constructed as a function of external magnetic field and injected
spin-polarized current. These diagrams show that applying larger fields and
currents has a stabilizing effect on magnetization precessions. Analytical
results are compared with numerical simulations of spin-transfer-driven
magnetization dynamics.",1001.4806v1
2013-08-29,Spin-orbit coupling and spin Hall effect for neutral atoms without spin-flips,"We propose a scheme which realizes spin-orbit coupling and the spin Hall
effect for neutral atoms in optical lattices without relying on near resonant
laser light to couple different spin states. The spin-orbit coupling is created
by modifying the motion of atoms in a spin-dependent way by laser recoil. The
spin selectivity is provided by Zeeman shifts created with a magnetic field
gradient. Alternatively, a quantum spin Hamiltonian can be created by
all-optical means using a period- tripling, spin-dependent superlattice.",1308.6349v1
2021-06-18,Inelastic spin-wave beam scattering by edge-localized spin waves in ferromagnetic thin film,"Spin waves are promising chargeless information carriers for the future,
energetically efficient beyond-CMOS systems. Among many advantages there are
the ease of achieving nonlinearity, the variety of possible interactions, and
excitation types. Although the rapidly developing magnonic research has already
yielded impressive realizations, multi-mode nonlinear effects, particularly
with the propagating waves and their nanoscale realizations, are still an open
research problem. We study theoretically the dynamic interactions of the spin
waves confined to the edge of a thin ferromagnetic film with the spin-wave beam
incident at this edge. We found the inelastically scattered spin-wave beams at
frequencies increased and decreased by the frequency of the edge spin-wave
relative to the specularly reflected beam. We observed a strong dependence of
the angular shift of the inelastic scattered spin-wave beam on the edge-mode
frequency, which allowed us to propose a magnonic demultiplexing of the signal
encoded in spin waves propagating along the edge. Since dynamic magnetostatic
interactions, which are ubiquitous in the spin-wave dynamics, are decisive in
this process, this indicates the possibility of implementing the presented
effects, also in other configurations and their use in magnonic systems.",2106.09954v3
2005-09-01,Magnetic resonance study of the spin-reorientation transitions in the quasi-one-dimensional antiferromagnet BaCu2Si2O7,"A quasi-one dimensional antiferromagnet with a strong reduction of the
ordered spin component, BaCu2Si2O7, is studied by the magnetic resonance
technique in a wide field and frequency range. Besides of conventional
spin-flop transition at the magnetic field parallel to the easy axis of spin
ordering, magnetic resonance spectra indicate additional spin-reorientation
transitions in all three principal orientations of magnetic field. At these
additional transitions the spins rotate in the plane perpendicular to the
magnetic field keeping the mutual arrangement of ordered spin components. The
observed magnetic resonance spectra and spin-reorientation phase transitions
are quantitatively described by a model including the anisotropy of transverse
susceptibility with respect to the order parameter orientation. The anisotropy
of the transverse susceptibility and the strong reduction of the anisotropy
energy due to the quantum spin fluctuations are proposed to be the reason of
the spin reorientations which are observed.",0509015v1
2003-04-18,RF depolarizing resonances in the presence of a full Siberian snake and full snake spin-flipping,"Frequent polarization reversals, or spin-flips, of a stored polarized beam in
a high energy scattering asymmetry experiments may greatly reduce systematic
errors of spin asymmetry measurements. A spin-flipping technique is being
developed by using rf magnets running at a frequency close to the spin
precession frequency, thereby creating spin-depolarizing resonances; the spin
can then be flipped by ramping the rf magnet's frequency through the resonance.
We studied, at the Indiana University Cyclotron Facility Cooler Ring,
properties of such rf depolarizing resonances in the presence of a nearly-full
Siberian snake and their possible application for spin-flipping. By using an
rf-solenoid magnet, we reached a 98.7% efficiency of spin-flipping. However, an
rf-dipole magnet is more practical at high energies; hence, studies of
spin-flipping by an rf-dipole are underway at IUCF.",0304066v1
2000-02-12,A model for ensemble NMR quantum computer using antiferromagnetic structure,"The one-dimensional homonuclear periodic array of nuclear spins I = 1/2,
owing to hyperfine interaction of nuclear spins with electronic magnetic
moments in antiferromagnetic structure, is considered. The neighbor nuclear
spins in such array are opposite oriented and have resonant frequencies
determined by hyperfine interaction constant, applied magnetic field value and
interaction with the left and right nuclear neighbor spins. The resonant
frequencies difference of nuclear spins, when the neighbor spins have different
and the same states, is used to control the spin dynamics by means of selective
resonant RF-pulses both for single nuclear spins and for ensemble of nuclear
spins with the same resonant frequency.
  A model for the NMR quantum computer of cellular-automata type based on an
one-dimensional homonuclear periodic array of spins is proposed. This model may
be generalized to a large ensemble of parallel working one-dimensional arrays
and to two-dimensional and three-dimensional structures.",0002034v1
2016-09-28,Resonant optical control of the spin of a single Cr atom in a quantum dot,"A Cr atom in a semiconductor host carries a localized spin with an intrinsic
large spin to strain coupling particularly promising for the development of
hybrid spin-mechanical systems and coherent mechanical spin driving. We
demonstrate here that the spin of an individual Cr atom inserted in a
semiconductor quantum dot can be controlled optically. We first show that a Cr
spin can be prepared by resonant optical pumping. Monitoring the time
dependence of the intensity of the resonant fluorescence of the quantum dot
during this process permits to probe the dynamics of the optical initialization
of the Cr spin. Using this initialization and read-out technique we measured a
Cr spin relaxation time at T=5 K of about 2 microseconds. We finally
demonstrate that, under a resonant single mode laser field, the energy of any
spin state of an individual Cr atom can be independently tuned by using the
optical Stark effect.",1609.08829v1
2018-06-25,Wideband and on-chip excitation for dynamical spin injection into graphene,"Graphene is an ideal material for spin transport as very long spin relaxation
times and lengths can be achieved even at room temperature. However, electrical
spin injection is challenging due to the conductivity mismatch problem. Spin
pumping driven by ferromagnetic resonance is a neat way to circumvent this
problem as it produces a pure spin current in the absence of a charge current.
Here, we show spin pumping into single layer graphene in micron scale devices.
A broadband on-chip RF current line is used to bring micron scale permalloy
(Ni$_{80}$Fe$_{20}$) pads to ferromagnetic resonance with a magnetic field
tunable resonance condition. At resonance, a spin current is emitted into
graphene, which is detected by the inverse spin hall voltage in a close-by
platinum electrode. Clear spin current signals are detected down to a power of
a few milliwatts over a frequency range of 2 GHz to 8 GHz. This compact device
scheme paves the way for more complex device structures and allows the
investigation of novel materials.",1806.09356v1
2021-07-20,Spin-wave dispersion measurement by variable-gap propagating spin-wave spectroscopy,"Magnonics is seen nowadays as a candidate technology for energy-efficient
data processing in classical and quantum systems. Pronounced nonlinearity,
anisotropy of dispersion relations and phase degree of freedom of spin waves
require advanced methodology for probing spin waves at room as well as at mK
temperatures. Yet, the use of the established optical techniques like Brillouin
light scattering (BLS) or magneto optical Kerr effect (MOKE) at ultra-low
temperatures is forbiddingly complicated. By contrast, microwave spectroscopy
can be used at all temperatures but is usually lacking spatial and wavenumber
resolution. Here, we develop a variable-gap propagating spin-wave spectroscopy
(VG-PSWS) method for the deduction of the dispersion relation of spin waves in
wide frequency and wavenumber range. The method is based on the phase-resolved
analysis of the spin-wave transmission between two antennas with variable
spacing, in conjunction with theoretical data treatment. We validate the method
for the in-plane magnetized CoFeB and YIG thin films in $k\perp B$ and
$k\parallel B$ geometries by deducing the full set of material and spin-wave
parameters, including spin-wave dispersion, hybridization of the fundamental
mode with the higher-order perpendicular standing spin-wave modes and surface
spin pinning. The compatibility of microwaves with low temperatures makes this
approach attractive for cryogenic magnonics at the nanoscale.",2107.09363v1
2023-01-16,Antiferromagnetic magnon spintronic based on non-reciprocal and non-degenerated ultra-fast spin-waves in the canted antiferromagnet α-Fe2O3,"Spin-waves in antiferromagnets hold the prospects for the development of
faster, less power-hungry electronics, as well as promising physics based on
spin-superfluids and coherent magnon-condensates. For both these perspectives,
addressing electrically coherent antiferromagnetic spin-waves is of importance,
a prerequisite that has so far been elusive, because unlike
ferromagnets,antiferromagnets couple weakly to radiofrequency fields. Here, we
demonstrate the detection of ultra-fast non-reciprocal spin-waves in the
dipolar-exchange regime of a canted antiferromagnet using both inductive and
spintronic transducers. Using time-of-flight spin-wave spectroscopy on hematite
({\alpha}-Fe2O3), we find that the magnon wave packets can propagate as fast as
20 km/s for reciprocal bulk spin-wave modes and up to 6 km/s for surface-spin
waves propagating parallel to the antiferromagnetic Neel vector. We finally
achieve efficient electrical detection of non-reciprocal spin-wave transport
using non-local inverse spin-Hall effects. The electrical detection of coherent
non-reciprocal antiferromagnetic spin waves paves the way for the development
of antiferromagnetic and altermagnet-based magnonic devices.",2301.06329v2
2008-07-02,Reversible quantum optical data storage based on resonant Raman optical field excited spin coherence,"A method of reversible quantum optical data storage is presented using
resonant Raman field excited spin coherence, where the spin coherence is stored
in an inhomogeneously broadened spin ensemble. Unlike the photon echo method,
present technique uses a 2 pi Raman optical rephasing pulse, and multimode
(parallel) optical channels can be utilized, where the multimode access gives a
great benefit to both all-optical and quantum information processing.",0807.0374v1
2011-01-03,The building blocks of magnonics,"Novel material properties can be realized by designing waves' dispersion
relations in artificial crystals. The crystal's structural length scales may
range from nano- (light) up to centimeters (sound waves). Because of their
emergent properties these materials are called metamaterials. Different to
photonics, where the dielectric constant dominantly determines the index of
refraction, in a ferromagnet the spin-wave index of refraction can be
dramatically changed already by the magnetization direction. This allows a
different flexibility in realizing dynamic wave guides or spin-wave switches.
The present review will give an introduction into the novel functionalities of
spin-wave devices, concepts for spin-wave based computing and magnonic
crystals. The parameters of the magnetic metamaterials are adjusted to the
spin-wave k-vector such that the magnonic band structure is designed. However,
already the elementary building block of an antidot lattice, the singular hole,
owns a strongly varying internal potential determined by its magnetic dipole
field and a localization of spin-wave modes. Photo-magnonics reveal a way to
investigate the control over the interplay between localization and
delocalization of the spin-wave modes using femtosecond lasers, which is a
major focus of this review. We will discuss the crucial parameters to realize
free Bloch states and how, by contrast, a controlled localization might allow
to gradually turn on and manipulate spin-wave interactions in spin-wave based
devices in the future.",1101.0479v2
2010-06-28,Stochastic resonance with matched filtering,"Along with the development of interferometric gravitational wave detector, we
enter into an epoch of gravitational wave astronomy, which will open a brand
new window for astrophysics to observe our universe. Almost all of the data
analysis methods in gravitational wave detection are based on matched
filtering. Gravitational wave detection is a typical example of weak signal
detection, and this weak signal is buried in strong instrument noise. So it
seems attractable if we can take advantage of stochastic resonance. But
unfortunately, almost all of the stochastic resonance theory is based on
Fourier transformation and has no relation to matched filtering. In this paper
we try to relate stochastic resonance to matched filtering. Our results show
that stochastic resonance can indeed be combined with matched filtering for
both periodic and non-periodic input signal. This encouraging result will be
the first step to apply stochastic resonance to matched filtering in
gravitational wave detection. In addition, based on matched filtering, we
firstly proposed a novel measurement method for stochastic resonance which is
valid for both periodic and non-periodic driven signal.",1006.5363v1
2010-07-12,Resonant Absorption as Mode Conversion?,"Resonant absorption and mode conversion are both extensively studied
mechanisms for wave ""absorption"" in solar magnetohydrodynamics (MHD). But are
they really distinct? We re-examine a well-known simple resonant absorption
model in a cold MHD plasma that places the resonance inside an evanescent
region. The normal mode solutions display the standard singular resonant
features. However, these same normal modes may be used to construct a ray
bundle which very clearly undergoes mode conversion to an Alfv\'en wave with no
singularities. We therefore conclude that resonant absorption and mode
conversion are in fact the same thing, at least for this model problem. The
prime distinguishing characteristic that determines which of the two
descriptions is most natural in a given circumstance is whether the converted
wave can provide a net escape of energy from the conversion/absorption region
of physical space. If it cannot, it is forced to run away in wavenumber space
instead, thereby generating the arbitrarily small scales in situ that we
recognize as fundamental to resonant absorption and phase mixing. On the other
hand, if the converted wave takes net energy way, singularities do not develop,
though phase mixing may still develop with distance as the wave recedes.",1007.1808v1
2019-09-18,Deep water gravity wave triad resonances on uniform flow,"Triad resonances for gravity waves propagating in opposite direction with
respect to uniform current are introduced. They are produced by multivalued and
anisotropic dispersion and occur even in deep water. In contrast, existing
literature suggests non-degenerate deep water triads require inhomogeneity or
capillary effects. In this sense, the new resonances are a first of their kind.
Analytical conditions for the existence of resonance may be reduced to
universal constants. Solution of a three-wave interaction model, adapted to the
wave-current problem, shows regimes wherein the dominant direction, speed and
strength of resonant energy transfer differs between wavenumber scales. This
suggests uniform current is a fundamental source of spatial inhomogeneity. The
new resonances significantly modify the picture of nonlinear interactions in
wave-current fields. Since the resonances are quadratic, they will also
dominate well known quartet interactions.",1909.08501v1
2006-10-24,Negative Energy Resonances of Bosons in a Magnetic Quadrupole Trap,"We investigate resonances of spin 1 bosons in a three-dimensional magnetic
quadrupole field. Complementary to the well-known positive energy resonances it
is shown that there exist short-lived, i.e. broad, negative energy resonances.
The latter are characterized by an atomic spin that is aligned antiparallel to
the local magnetic field direction. In contrast to the positive energy
resonances the lifetimes of the negative energy resonances decreases with
increasing total magnetic quantum number. We derive a mapping of the two
branches of the spectrum.",0610207v1
2005-06-24,Quasi-Periodic Oscillations Resonantly Induced on Spin-Induced Deformed-Disks of Neutron Stars,"We consider the situation where a spin-induced wavy perturbation is present
on disks of neutron-star low-mass X-ray binaries. By non-linearly coupling with
the perturbation, some modes of disk oscillations resonantly interact with the
disks. We examine the resonant conditions under the assumption that the disks
are vertically isothermal. The results show that when the spin frequency has
some particular values, resonant coupling occurs at some radii. The modes and
frequencies of these resonant oscillations are summarized. Some of these
resonant oscillations seem to explain the frequencies of the observed kHz QPOs
in objects of which the spin frequency is known.",0506595v1
1998-07-21,Single Molecule Magnetic Resonance and Quantum Computation,"It is proposed that nuclear (or electron) spins in a trapped molecule would
be well isolated from the environment and the state of each spin can be
measured by means of mechanical detection of magnetic resonance. Therefore
molecular traps make an entirely new approach possible for spin-resonance
quantum computation which can be conveniently scaled up. In the context of
magnetic resonance spectroscopy, a molecular trap promises the ultimate
sensitivity for single spin detection and an unprecedented spectral resolution
as well.",9807057v2
2008-05-19,Vibrational coherence in electron spin resonance in nanoscale oscillators,"We study a scheme for electrical detection, using electron spin resonance, of
coherent vibrations in a molecular single electron level trapped near a
conduction channel. Both equilibrium spin-currents and non-equilibrium spin-
and charge currents are investigated. Inelastic side-band anti-resonances
corresponding to the vibrational modes appear in the electron spin resonance
spectrum.",0805.2919v2
2008-12-12,Force-detected nuclear double resonance between statistical spin polarizations,"We demonstrate nuclear double resonance for nanometer-scale volumes of spins
where random fluctuations rather than Boltzmann polarization dominate. When the
Hartmann-Hahn condition is met in a cross-polarization experiment, flip-flops
occur between two species of spins and their fluctuations become coupled. We
use magnetic resonance force microscopy to measure this effect between 1H and
13C spins in 13C-enriched stearic acid. The development of a cross-polarization
technique for statistical ensembles adds an important tool for generating
chemical contrast in nanometer-scale magnetic resonance.",0812.2274v1
2010-08-06,Spin Resonance and dc Current Generation in a Quantum Wire,"We show that in a quantum wire the spin-orbit interaction leads to a narrow
spin resonance at low temperatures, even in the absence of an external magnetic
field. A relatively weak dc magnetic field of a definite direction strongly
increases the resonance absorption. Linearly polarized resonance radiation
produces dynamic magnetization as well as electric and spin currents. The
effect strongly depends on the external magnetic field.",1008.1225v1
2010-09-21,Electron Spin Resonance of the ferromagnetic Kondo lattice CeRuPO,"The spin dynamics of the ferromagnetic Kondo lattice CeRuPO is investigated
by Electron Spin Resonance (ESR) at microwave frequencies of 1, 9.4, and
34~GHz. The measured resonance can be ascribed to a rarely observed bulk Ce3+
resonance in a metallic Ce compound and can be followed below the ferromagnetic
transition temperature Tc=14 K. At T>Tc the interplay between the RKKY-exchange
interaction and the crystal electric field anisotropy determines the ESR
parameters. Near Tc the spin relaxation rate is influenced by the critical
fluctuations of the order parameter.",1009.4108v1
2008-10-30,Magnetoelectric Spin Wave Amplifier for Spin Wave Logic Circuits,"We propose and analyze a spin wave amplifier aimed to enhance the amplitude
of the propagating spin wave via the magnetoelectric effect. The amplifier is a
two-layer multiferroic structure, which comprises piezoelectric and
ferromagnetic materials. By applying electric field to the piezoelectric layer,
the stress is produced. In turn, the stress changes the direction of the easy
axis in the ferromagnetic layer and the direction of the anisotropy field. The
rotation frequency of the easy axis is the same as the frequency of the spin
wave propagating through the ferromagnetic layer. As a result of this two-stage
process, the amplitude of the spin wave can be amplified depending on the angle
of the easy axis rotation. We present results of numerical simulations
illustrating the operation of the proposed amplifier. According to numerical
estimates, the amplitude of the spin wave signal can be increased by several
orders of magnitude. The energy efficiency of the electric-to-magnetic power
conversion is discussed. The proposed amplifier preserves the phase of the
initial signal, which is important for application to logic circuits based on
spin waves.",0810.5586v1
2013-11-08,Spin wave nonreciprocity for logic device applications,"The utilization of spin waves as eigenmodes of the magnetization dynamics for
information processing and communication has been widely explored recently due
to its high operational speed with low power consumption and possible
applications for quantum computations. Previous proposals of spin wave
Mach-Zehnder devices were based on the spin wave phase, a delicate entity which
can be easily disrupted. Here, we propose a complete logic system based on the
spin wave amplitude utilizing the nonreciprocal spin wave behavior excited by
microstrip antennas. The experimental data reveal that the nonreciprocity of
magnetostatic surface spin wave can be tuned by the bias magnetic field.
Furthermore, engineering of the device structure could result in a high
nonreciprocity factor for spin wave logic applications.",1311.1881v1
2017-05-09,Unidirectional control of optically induced spin waves,"Unidirectional control of optically induced spin waves in a rare-earth iron
garnet crystal is demonstrated. We observed the interference of two spin-wave
packets with different initial phases generated by circularly polarized light
pulses. This interference results in unidirectional propagation if the
spin-wave sources are spaced apart at 1/4 of the wavelength of the spin waves
and the initial phase difference is set to pi/2. The propagating direction of
the spin wave is switched by the polarization helicity of the light pulses.
Moreover, in a numerical simulation, applying more than two spin-wave sources
with a suitable polarization and spot shape, arbitrary manipulation of the spin
wave by the phased array method was replicated.",1705.03349v1
2021-09-21,Chiral Surface Wave propagation with Anomalous Spin-momentum Locking,"The ability to control the directionality of surface waves by manipulating
its polarization has been of great significance for applications in spintronics
and polarization-based optics. Surface waves with evanescent tails are found to
possess an inherent in-plane transverse spin which is dependent on the
propagation direction while an out-of-plane transverse spin does not naturally
occur for surface waves and requires a specific surface design. Here, we
introduce a new type of surface waves called chiral surface wave which has two
transverse spins, an in-plane one that is inherent to any surface wave and an
out-of-plane spin which is enforced by the design due to strong x-to-y coupling
and broken rotational symmetry. The two transverse spins are locked to the
momentum. Our study opens a new direction for metasurface designs with enhanced
and controlled spin-orbit interaction by adding an extra degree of freedom to
control the propagation direction as well as the transverse spin of surface
waves.",2109.10314v1
2023-09-29,Evanescent Electron Wave Spin,"Our study shows that an evanescent electron wave exists outside both finite
and infinite quantum wells, by solving exact solutions of the Dirac equation in
a cylindrical quantum well and maintaining wavefunction continuity at the
boundary. Furthermore, we demonstrate that the evanescent wave spins
concurrently with the wave inside the quantum well, by deriving analytical
expressions of the current density in the whole region. Our findings suggest
that it is possible to probe or eavesdrop on quantum spin information through
the evanescent wave spin without destroying the entire spin state. The wave
spin picture interprets spin as a global and deterministic property of the
electron wave that includes both the evanescent and confined wavefunctions.
This suggests that a quantum process or device based on the manipulation and
probing of the electron wave spin is deterministic in nature rather than
probabilistic.",2309.17325v3
2023-10-20,Optical spin waves,"Chirality is inherent to a broad range of systems, including in solid-state
and wave physics. The precession (chiral motion) of electron spins in magnetic
materials, forming spin waves, has various properties and many applications in
magnetism and spintronics. We show that an optical analog of spin waves can be
generated in arrays of plasmonic nanohelices. Such optical waves arise from the
interaction between chiral helix eigenmodes carrying spin angular momentum. We
demonstrate that these optical spin waves are reflected at the interface
between successive domains of enantiomeric nanohelices, forming a heterochiral
lattice, regardless of the wave propagation direction within the lattice.
Optical spin waves may be applied in techniques involving photon spin, ranging
from data processing and storage to quantum optics.",2310.13600v2
2024-03-22,Interference patterns of propagating spin wave in spin Hall oscillator arrays,"In this study, we discuss the observation of spin wave interference generated
by magnetic oscillators. We employ micromagnetic simulations for two coherent
spin Hall nanowire oscillators positioned nearby, horizontally or vertically.
The two nanowires produce circular waves with short wavelengths on the order of
100 nm, which interfere with each other. In the horizontal configuration, the
spin waves exhibit constructive and destructive fringes, indicating
amplification or cancellation of the amplitudes, respectively. The
synchronization of spin waves in the current geometry of the two nanowires is
facilitated by the combination of dipolar field and propagating spin waves.
Additionally, the vertical alignment results in standing spin waves
characterized by multiple antinodes and nodes. These observations are
interpreted using a wave model that incorporates the superposition principle
for each case.",2403.15060v1
2004-01-21,Resonance tongues and patterns in periodically forced reaction-diffusion systems,"Various resonant and near-resonant patterns form in a light-sensitive
Belousov-Zhabotinsky (BZ) reaction in response to a spatially-homogeneous
time-periodic perturbation with light. The regions (tongues) in the forcing
frequency and forcing amplitude parameter plane where resonant patterns form
are identified through analysis of the temporal response of the patterns.
Resonant and near-resonant responses are distinguished. The unforced BZ
reaction shows both spatially-uniform oscillations and rotating spiral waves,
while the forced system shows patterns such as standing-wave labyrinths and
rotating spiral waves. The patterns depend on the amplitude and frequency of
the perturbation, and also on whether the system responds to the forcing near
the uniform oscillation frequency or the spiral wave frequency. Numerical
simulations of a forced FitzHugh-Nagumo reaction-diffusion model show both
resonant and near-resonant patterns similar to the BZ chemical system.",0401031v1
2021-09-23,Quantum nonlinear spectroscopy of single nuclear spins,"Nonlinear spectroscopy is widely used for studying physical systems.
Conventional nonlinear optical spectroscopy and magnetic resonance
spectroscopy, which use classical probes such as electromagnetic waves, can
only access certain types of correlations in a quantum system. The idea of
quantum nonlinear spectroscopy was recently proposed to use quantum probes such
as entangled photons to achieve sensitivities and resolutions beyond the
classical limits. It is shown that quantum sensing can extract arbitrary types
and orders of correlations in a quantum system by first quantum-entangling a
sensor and the object and then measuring the sensor. Quantum sensing has been
applied to achieve nuclear magnetic resonance (NMR) of single atoms and the
second-order correlation spectroscopy has been adopted to enhance the spectral
resolution. However, quantum nonlinear spectroscopy (i.e., the measurement of
higher-order correlations) of single nuclear spins is still elusive. Here we
demonstrate the extraction of fourth-order correlations of single nuclear spins
that cannot be measured in conventional nonlinear spectroscopy, using
sequential weak measurement via an atomic quantum sensor, namely, a
nitrogen-vacancy center in diamond. We show that the quantum nonlinear
spectroscopy provides fingerprint features to identify different types of
objects, such as Gaussian noises, random-phased AC fields, and quantum spins,
which would be indistinguishable in second-order correlations. The measured
fourth-order correlation unambiguously differentiates a single nuclear spin and
a random-phased AC field. This work constitutes an initial step toward the
application of higher-order correlations to quantum sensing, to examining the
quantum foundation (by, e.g., higher-order Leggett-Garg inequality), and to
studying quantum many-body physics.",2109.11170v1
2021-07-21,Brillouin Light Scattering from Quantized Spin Waves in Nanowires with Antisymmetric Exchange Interactions,"Antisymmetric exchange interactions lead to non-reciprocal spin-wave
propagation. As a result, spin waves confined in a nanostructure are not
standing waves; they have a time-dependent phase, because counter-propagating
waves of the same frequency have different wavelengths. We report on a
Brillouin light scattering (BLS) study of confined spin waves in Co/Pt
nanowires with strong Dzyaloshinskii-Moriya interactions (DMI). Spin-wave
quantization in narrow ($\lesssim 200$ nm width) wires dramatically reduces the
frequency shift between BLS Stokes and anti-Stokes lines associated with the
scattering of light incident transverse to the nanowires. In contrast, the BLS
frequency shift associated with the scattering of spin waves propagating along
the nanowire length is independent of nanowire width. A model that considers
the chiral nature of modes captures this physics and predicts a dramatic
reduction in frequency shift of light scattered from higher energy spin waves
in narrow wires, which is confirmed by our experiments.",2107.10303v2
2023-08-02,Spin wave amplification through superradiance,"Superradiance is a phenomenon of multiple facets that occurs in classical and
quantum physics under extreme conditions. Here we present its manifestation in
spin waves under an easily realized condition. We show that an interface
between a current-free (normal) ferromagnetic (FM) region and a current-flow
(pumped) FM region can be a spin wave super-mirror whose reflection coefficient
is larger than 1. The super-reflection is the consequence of current-induced
spectrum inversion where phase and group velocities of spin waves are in the
opposite directions. An incident spin wave activates a backward propagating
refractive wave inside pumped FM region. The refractive spin wave re-enters the
normal FM region to constructively interfere with the reflective wave. It
appears that the pumped FM region coherently emits reflective waves, leading to
a super-reflection. The process resembles superradiance of a spinning black
hole through the Hawking radiation process, or Dicke superradiance of cavity
photons inside population inverted media.",2308.00962v1
2015-08-21,Inhomogeneous nuclear spin polarization induced by helicity-modulated optical excitation of fluorine-bound electron spins in ZnSe,"Optically-induced nuclear spin polarization in a fluorine-doped ZnSe epilayer
is studied by time-resolved Kerr rotation using resonant excitation of
donor-bound excitons. Excitation with helicity-modulated laser pulses results
in a transverse nuclear spin polarization, which is detected as a change of the
Larmor precession frequency of the donor-bound electron spins. The frequency
shift in dependence on the transverse magnetic field exhibits a pronounced
dispersion-like shape with resonances at the fields of nuclear magnetic
resonance of the constituent zinc and selenium isotopes. It is studied as a
function of external parameters, particularly of constant and radio frequency
external magnetic fields. The width of the resonance and its shape indicate a
strong spatial inhomogeneity of the nuclear spin polarization in the vicinity
of a fluorine donor. A mechanism of optically-induced nuclear spin polarization
is suggested based on the concept of resonant nuclear spin cooling driven by
the inhomogeneous Knight field of the donor-bound electron.",1508.05295v1
2017-03-28,Resonant photoluminescence and dynamics of a hybrid Mn-hole spin in a positively charged magnetic quantum dot,"We analyze, through resonant photoluminescence, the spin dynamics of an
individual magnetic atom (Mn) coupled to a hole in a semiconductor quantum dot.
The hybrid Mn-hole spin and the positively charged exciton in a CdTe/ZnTe
quantum dot forms an ensemble of $\Lambda$ systems which can be addressed
optically. Auto-correlation of the resonant photoluminescence and resonant
optical pumping experiments are used to study the spin relaxation channels in
this multilevel spin system. We identified for the hybrid Mn-hole spin an
efficient relaxation channel driven by the interplay of the Mn-hole exchange
interaction and the coupling to acoustic phonons. We also show that the optical
$\Lambda$ systems are connected through inefficient spin-flips than can be
enhanced under weak transverse magnetic field. The dynamics of the resonant
photoluminescence in a p-doped magnetic quantum dot is well described by a
complete rate equation model. Our results suggest that long lived hybrid
Mn-hole spin could be obtained in quantum dot systems with large
heavy-hole/light-hole splitting.",1703.09441v2
2003-10-08,Tidal dissipation in rotating giant planets,"[Abridged] Tides may play an important role in determining the observed
distributions of mass, orbital period, and eccentricity of the extrasolar
planets. In addition, tidal interactions between giant planets in the solar
system and their moons are thought to be responsible for the orbital migration
of the satellites, leading to their capture into resonant configurations. We
treat the underlying fluid dynamical problem with the aim of determining the
efficiency of tidal dissipation in gaseous giant planets. In cases of interest,
the tidal forcing frequencies are comparable to the spin frequency of the
planet but small compared to its dynamical frequency. We therefore study the
linearized response of a slowly and possibly differentially rotating planet to
low-frequency tidal forcing. Convective regions of the planet support inertial
waves, while any radiative regions support generalized Hough waves. We present
illustrative numerical calculations of the tidal dissipation rate and argue
that inertial waves provide a natural avenue for efficient tidal dissipation in
most cases of interest. The resulting value of Q depends in a highly erratic
way on the forcing frequency, but we provide evidence that the relevant
frequency-averaged dissipation rate may be asymptotically independent of the
viscosity in the limit of small Ekman number. In short-period extrasolar
planets, if the stellar irradiation of the planet leads to the formation of a
radiative outer layer that supports generalized Hough modes, the tidal
dissipation rate can be enhanced through the excitation and damping of these
waves. These dissipative mechanisms offer a promising explanation of the
historical evolution and current state of the Galilean satellites as well as
the observed circularization of the orbits of short-period extrasolar planets.",0310218v1
1999-11-09,Collective modes and sound propagation in a p-wave superconductor: Sr$_2$RuO$_4$,"There are five distinct collective modes in the recently discovered p-wave
superconductor Sr$_2$RuO$_4$; phase and amplitude modes of the order parameter,
clapping mode (real and imaginary), and spin wave. The first two modes also
exist in the ordinary s-wave superconductors, while the clapping mode with the
energy $\sqrt{2} \Delta(T)$ is unique to Sr$_2$RuO$_4$ and couples to the sound
wave. Here we report a theoretical study of the sound propagation in a two
dimensional p-wave superconductor. We identified the clapping mode and study
its effects on the longitudinal and transverse sound velocities in the
superconducting state. In contrast to the case of $^3$He, there is no resonance
absorption associated with the collective mode, since in metals $\omega/(v_F
|{\bf q}|) \ll 1$, where $v_F$ is the Fermi velocity, {\bf q} is the wave
vector, and $\omega$ is the frequency of the sound wave. However, the velocity
change in the collisionless limit gets modified by the contribution from the
coupling to the clapping mode. We compute this contribution and comment on the
visibility of the effect. In the diffusive limit, the contribution from the
collective mode turns out to be negligible. The behaviors of the sound velocity
change and the attenuation coefficient near $T_c$ in the diffusive limit are
calculated and compared with the existing experimental data wherever it is
possible. We also present the results for the attenuation coefficients in both
of the collisionless and diffusive limits at finite temperatures.",9911131v2
2015-09-25,Multi-Wave Coherent Control of a Solid State Single Emitter,"Coherent control of individual two-level systems (TLSs) is at the basis of
any implementation of quantum information. An impressive level of control is
now achieved using nuclear, vacancies and charge spins. Manipulation of bright
exciton transitions in semiconductor quantum dots (QDs) is less advanced,
principally due to the sub-nanosecond dephasing. Conversely, owing to their
robust coupling to light, one can apply tools of nonlinear spectroscopy to
achieve all-optical command. Here, we report on the coherent manipulation of an
exciton via multi-wave mixing. Specifically, we employ three resonant pulses
driving a single InAs QD. The first two induce a four-wave mixing (FWM)
transient, which is projected onto a six-wave mixing (SWM) depending on the
delay and area of the third pulse, in agreement with analytical predictions.
Such a switch enables to demonstrate the generation of SWM on a single emitter
and to engineer the spectro-temporal shape of the coherent response originating
from a TLS. These results pave the way toward multi-pulse manipulations of
solid state qubits via implementing the NMR-like control schemes in the optical
domain.",1509.07690v3
2019-11-25,Large non-reciprocal propagation of surface acoustic waves in epitaxial ferromagnetic/semiconductor hybrid structures,"Non-reciprocal propagation of sound, that is, the different transmission of
acoustic waves traveling along opposite directions, is a challenging
requirement for the realization of devices like acoustic isolators and
circulators. Here, we demonstrate the efficient non-reciprocal transmission of
surface acoustic waves (SAWs) propagating along opposite directions of a GaAs
substrate coated with an epitaxial Fe$_3$Si film. The non-reciprocity arises
from the acoustic attenuation induced by the magneto-elastic (ME) interaction
between the SAW strain field and spin waves in the ferromagnetic film, which
depends on the SAW propagation direction and can be controlled via the
amplitude and orientation of an external magnetic field. The acoustic
transmission non-reciprocity, defined as the difference between the transmitted
acoustic power for forward and backward propagation under ME resonance, reaches
values of up to 20%, which are, to our knowledge, the largest non-reciprocity
reported for SAWs traveling along a semiconducting piezoelectric substrate
covered by a ferromagnetic film. The experimental results are well accounted
for by a model for ME interaction, which also shows that non-reciprocity can be
further enhanced by optimization of the sample design. These results make
Fe$_3$Si/GaAs a promising platform for the realization of efficient
non-reciprocal SAW devices.",1911.11072v3
2018-10-24,Observation of two types of charge density wave orders in superconducting La$_{2-x}$Sr$_x$CuO$_4$,"The discovery of charge- and spin-density-wave (CDW/SDW) orders in
superconducting cuprates has altered our perspective on the nature of
high-temperature superconductivity (SC). However, it has proven difficult to
fully elucidate the relationship between the density wave orders and SC. Here
using resonant soft X-ray scattering we study the archetypal cuprate,
La$_{2-x}$Sr$_x$CuO$_4$ (LSCO) over a broad doping range. We reveal the
existence of two types of CDW orders in LSCO, namely CDW stripe order and CDW
short-range order (SRO). While the CDW-SRO is suppressed by SC, it is partially
transformed into the CDW stripe order with developing SDW stripe order near the
superconducting $T_{\rm c}$. These findings indicate that the stripe orders and
SC are inhomogeneously distributed in the superconducting CuO$_2$ planes of
LSCO. This further suggests a new perspective on the putative pair-density-wave
order that coexists with SC, SDW, and CDW orders.",1810.10600v2
2024-01-19,Nonreciprocal Pancharatnam-Berry Metasurface for Unidirectional Wavefront Manipulation,"Optical metasurfaces have been widely used for manipulating electromagnetic
waves due to their low intrinsic loss and easy fabrication. The metasurfaces
employing the Pancharatnam-Berry (PB) geometric phase, called PB metasurfaces,
have been extensively applied to realize spin-dependent functionalities, such
as beam steering, focusing, holography, etc. The demand for PB metasurfaces in
complex environments has brought about one challenging problem, i.e., the
interference of multiple wave channels that limits the performance of PB
metasurfaces. A promising solution is developing nonreciprocal PB metasurfaces
that can isolate undesired wave channels and exhibit unidirectional
functionalities. Here, we propose a mechanism to realize nonreciprocal PB
metasurfaces of subwavelength thickness by using the magneto-optical effect of
YIG material in synergy with the PB geometric phase of spatially rotating
meta-atoms. Using full-wave numerical simulations, we show that the metasurface
composed of dielectric cylinders and a thin YIG layer can achieve nearly 92%
and 81% isolation of circularly polarized lights at 5.5 GHz and 6.5 GHz,
respectively, attributed to the enhancement of the magneto-optical effect by
the resonant Mie modes and Fabry-P\'erot cavity mode. In addition, the
metasurface can enable efficient unidirectional wavefront manipulations of
circularly polarized lights, including nonreciprocal beam steering and
nonreciprocal beam focusing. The proposed metasurface can find highly useful
applications in optical communications, optical sensing, and quantum
information processing.",2401.10772v2
2008-01-30,Spin waves in disordered magnetic systems,"Long-wavelength spin waves in disordered magnetic systems have been
investigated. In the framework of the Heisenberg model with magnetic dipole and
exchange interactions between spins it is found that an additional longitudinal
spin wave mode appears. This mode is characterized by variations of the value
of the magnetic moment density. In order to analyse influence of the magnetic
disorder on spin wave dispersion relations, the special case of volume and
surface spin waves in the Damon-Eshbach (DE) geometry in films with magnetic
disorder is considered. It is revealed strong influence of the magnetic
disorder on surface spin waves, which consist of two branches -- the DE mode
and the longitudinal spin wave mode. Decrease of the ordering parameters leads
to a decrease of the initial frequency and the curve slope of the DE mode
dispersion curve and to an increase of the dispersion curve slope of the
longitudinal mode. If the spin noncollinearity is high, then the DE mode
dispersion assumes a curve with the backward character. It is found that the
dispersion relation of the longitudinal mode is weak temperature dependent. The
developed model can explain the observed double-peak structure of FMR spectra
in magnetic nanocomposites.",0801.4633v1
2016-03-24,Separated spin evolution quantum hydrodynamics of degenerated electrons with spin-orbit interaction and extraordinary wave spectrum,"To consider a contribution of the spin-orbit interaction in the extraordinary
wave spectrum we derive a generalization of the separate spin evolution quantum
hydrodynamics. Applying corresponding nonlinear Pauli equation we include Fermi
spin current contribution in the spin evolution. We find that the spectrum of
extraordinary waves consists of three branches: two of them are well-known
extraordinary waves and the third one is the spin-electron acoustic wave
(SEAW). Earlier SEAWs have been considered in the electrostatic limit. Here we
include the electromagnetic effects in their spectrum at the propagation
perpendicular to the external magnetic field. We find that the SEAW spectrum
considerably changes at the account of transverse part of electric field. We
obtain that the separate spin evolution modifies spectrum of the well-known
extraordinary waves either. A change of the extraordinary wave spectrum due to
the spin-orbit interaction is obtained as well.",1603.07506v1
2017-10-22,Kinetic description of the oblique propagating spin-electron acoustic waves in degenerate plasmas,"Oblique propagation of the spin-electron acoustic waves in degenerate
magnetized plasmas is considered in terms of quantum kinetics with the separate
spin evolution, where the spin-up electrons and the spin-down electrons are
considered as two different species with different equilibrium distributions.
It is considered in the electrostatic limit. Corresponding dispersion equation
is derived. Analytical analysis of the dispersion equation is performed in the
long-wavelength limit to find an approximate dispersion equation describing the
spin-electron acoustic wave. The approximate dispersion equation is solved
numerically. Real and imaginary parts of the spin-electron acoustic wave
frequency are calculated for different values of the parameters describing the
system. It is found that the increase of angle between direction of wave
propagation and the external magnetic field reduces the real and imaginary
parts of spin-electron acoustic wave frequency. The increase of the spin
polarization decreases the real and imaginary parts of frequency either. The
imaginary part of frequency has nonmonotonic dependence on the wave vector
which shows a single maximum. The imaginary part of frequency is small in
compare with the real part for all parameters in the area of applicability of
the obtained dispersion equation.",1710.08040v1
2019-05-09,Bidirectional spin-wave-driven domain wall motion in antiferromagnetically coupled ferrimagnets,"We investigate ferrimagnetic domain wall dynamics induced by circularly
polarized spin waves theoretically and numerically. We find that the direction
of domain wall motion depends on both the circular polarization of spin waves
and the sign of net spin density of ferrimagnet. Below the angular momentum
compensation point, left- (right-) circularly polarized spin waves push a
domain wall towards (away from) the spin-wave source. Above the angular
momentum compensation point, on the other hand, the direction of domain wall
motion is reversed. This bidirectional motion originates from the fact that the
sign of spin-wave-induced magnonic torque depends on the circular polarization
and the subsequent response of the domain wall to the magnonic torque is
governed by the net spin density. Our finding provides a way to utilize a spin
wave as a versatile driving force for bidirectional domain wall motion.",1905.03521v1
2017-03-24,"Linking structure and dynamics in $(p,pn)$ reactions with Borromean nuclei: the $^{11}$Li$(p,pn){^{10}}$Li case","One-neutron removal $(p,pn)$ reactions induced by two-neutron Borromean
nuclei are studied within a Transfer-to-the-Continuum (TC) reaction framework,
which incorporates the three-body character of the incident nucleus. The
relative energy distribution of the residual unbound two-body subsystem, which
is assumed to retain information on the structure of the original three-body
projectile, is computed by evaluating the transition amplitude for different
neutron-core final states in the continuum. These transition amplitudes depend
on the overlaps between the original three-body ground-state wave function and
the two-body continuum states populated in the reaction, thus ensuring a
consistent description of the incident and final nuclei. By comparing different
$^{11}$Li three-body models, it is found that the $^{11}$Li$(p,pn){^{10}}$Li
relative energy spectrum is very sensitive to the position of the $p_{1/2}$ and
$s_{1/2}$ states in $^{10}$Li and to the partial wave content of these
configurations within the $^{11}$Li ground-state wave function. The possible
presence of a low-lying $d_{5/2}$ resonance is discussed. The coupling of the
single particle configurations with the non-zero spin of the $^{9}$Li core,
which produces a spin-spin splitting of the states, is also studied. Among the
considered models, the best agreement with the available data is obtained with
a $^{11}$Li model that incorporates the actual spin of the core and contains
$\sim$31\% of $p_{1/2}$-wave content in the $n$-$^9$Li subsystem, in accord
with our previous findings for the $^{11}$Li(p,d)$^{10}$Li transfer reaction,
and a near-threshold virtual state.",1703.08320v1
2022-08-27,The missing link between standing- and traveling-wave resonators,"Optical resonators are structures that utilize wave interference and feedback
to confine light in all three dimensions. Depending on the feedback mechanism,
resonators can support either standing- or traveling-wave modes. Over the
years, the distinction between these two different types of modes has become so
prevalent that nowadays it is one of the main characteristics for classifying
optical resonators. Here, we show that an intermediate link between these two
rather different groups exists. In particular, we introduce a new class of
photonic resonators that supports a hybrid optical mode, i.e. at one location
along the resonator the electromagnetic fields associated with the mode feature
a purely standing-wave pattern, while at a different location, the fields of
the same mode represent a pure traveling wave. The proposed concept is general
and can be implemented using chip-scale photonics as well as free-space optics.
Moreover, it can be extended to other wave phenomena such as microwaves and
acoustics.",2208.12905v1
2023-04-04,Experimental Evidence of Amplitude-Dependent Surface Wave Dispersion via Nonlinear Contact Resonances,"In this letter, we provide an experimental demonstration of
amplitude-dependent dispersion tuning of surface acoustic waves interacting
with nonlinear resonators. Leveraging the similarity between the dispersion
properties of plate edge waves and surface waves propagating in a semi-infinite
medium, we use a setup consisting of a plate with a periodic arrangement of
bead-magnet resonators along one of its edges. Nonlinear contact between the
ferromagnetic beads and magnets is exploited to realize nonlinear local
resonance effects. First, we experimentally demonstrate the nonlinear softening
nature and amplitude-dependent dynamics of a single bead-magnet resonator on
both rigid and compliant substrates. Next, the dispersion properties of the
system in the linear regime are investigated. Finally, we demonstrate how the
interplay of nonlinear local resonances with plate edge waves gives rise to
amplitude-dependent dispersion properties. The findings will inform the design
of more versatile surface acoustic wave devices that can passively adapt to
loading conditions.",2304.01494v2
2023-08-11,Electron resonant interaction with whistler-mode waves around the Earth's bow shock II: the mapping technique,"Electron resonant scattering by high-frequency electromagnetic whistler-mode
waves has been proposed as a mechanism for solar wind electron scattering and
pre-acceleration to energies that enable them to participate in shock drift
acceleration around the Earth's bow shock. However, observed whistler-mode
waves are often sufficiently intense to resonate with electrons nonlinearly,
which prohibits the application of quasi-linear diffusion theory. This is the
second of two accompanying papers devoted to developing a new theoretical
approach for quantifying the electron distribution evolution subject to
multiple resonant interactions with intense whistler-mode wave-packets. In the
first paper, we described a probabilistic approach, applicable to systems with
short wave-packets. For such systems, nonlinear resonant effects can be treated
by diffusion theory, but with diffusion rates different from those of
quasi-linear diffusion. In this paper we generalize this approach by merging it
with a mapping technique. This technique can be used to model the electron
distribution evolution in the presence of significantly non-diffusive resonant
scattering by intense long wave-packets. We verify our technique by comparing
its predictions with results from a numerical integration approach.",2308.05909v1
2017-08-15,Group-wave resonances in nonlinear dispersive media: The case of gravity water waves,"The dynamics of coherent nonlinear wave groups is shown to be drastically
different from the classical scenario of weakly nonlinear wave interactions.
The coherent groups generate non-resonant (bound) waves which can be
synchronized with other linear waves. By virtue of the revealed mechanism the
groups may emit waves with similar or different lengths, which propagate in the
same or opposite direction.",1708.04564v3
2017-05-26,Edge waves and localisation in lattices containing tilted resonators,"The paper presents the study of waves in a structured geometrically chiral
solid. A special attention is given to the analysis of the Bloch-Floquet waves
in a doubly periodic high-contrast lattice containing tilted resonators.
Dirac-like dispersion of Bloch waves in the structure is identified, studied
and applied to wave-guiding and wave-defect interaction problems. The work is
extended to the transmission problems and models of fracture, where
localisation and edge waves occur. The theoretical derivations are accompanied
with numerical simulations and illustrations.",1705.09726v1
2016-11-18,Propagating spin-wave normal modes: A dynamic matrix approach using plane-wave demagnetizating tensors,"We present a finite-difference micromagnetic approach for determining the
normal modes of spin-waves propagating in extended magnetic films and strips,
which is based on the linearized Landau-Lifshitz equation and uses the dynamic
matrix method. The model takes into account both short range exchange
interactions and long range dipole-dipole interactions. The latter are
accounted for through plane-wave dynamic demagnetization factors, which depend
not only on the geometry and relative positions of the magnetic cells, as usual
demagnetization factors do, but also on the wave vector of the propagating
waves. Such a numerical model is most relevant when the spin-wave medium is
spatially inhomogeneous perpendicular to the direction of propagation, either
in its magnetic properties or in its equilibrium magnetic configuration. We
illustrate this point by studying surface spin-waves in magnetic bilayer films
and spin-waves channelized along magnetic domain walls in perpendicularly
magnetized strips. In both cases, dynamic dipolar interactions produce
non-reciprocity effects, where counter-propagative spin-waves have different
frequencies.",1611.06153v1
2023-05-17,Spin-wave dynamics controlled by tunable ac magnonic crystal,"The magnonic crystal, which has a spatial modulation wave vector $q$, couples
the spin wave with wave vector $k$ to the one with wave vector $k-q$. For a
conventional magnonic crystal with direct current (dc) supply, the spin waves
around $q/2$ are resonantly coupled to the waves near $-q/2$, and a band gap is
opened at $k=\pm q/2$. If instead of the dc current the magnonic crystal is
supplied with an alternating current (ac), then the band gap is \emph{shifted}
to $k$ satisfying $|\omega_{s}(k)-\omega_{s}(k-q)|=\omega_{ac}$; here
$\omega_{s}(k)$ is the dispersion of the spin wave, while $\omega_{ac}$ is the
frequency of the ac modulation. The resulting gap in the case of the ac
magnonic crystal is the half of the one caused by the dc with the same
amplitude of modulation. The time evolution of the resonantly coupled spin
waves controlled by properly suited ac pulses can be well interpreted as the
motion on a Bloch sphere. The tunability of the ac magnonic crystal broadens
the perspective of spin-wave computing.",2305.09876v1
2021-08-25,Probing Kondo spin fluctuations with scanning tunneling microscopy and electron spin resonance,"We theoretically analyze a state-of-the-art experimental method based on a
combination of electron spin resonance and scanning tunneling microscopy
(ESR-STM), to directly probe the spin fluctuations in the Kondo effect. The
Kondo impurity is exchange coupled to the probe spin, and the ESR-STM setup
detects the small level shifts in the probe spin induced by the spin
fluctuations of the Kondo impurity. We use the open quantum system approach by
regarding the probe spin as the ""system"" and the Kondo impurity spin as the
fluctuating ""bath"" to evaluate the resonance line shifts in terms of the
dynamic spin susceptibility of the Kondo impurity. We consider various common
adatoms on surfaces as possible probe spins and estimate the corresponding
level shifts. It is found that the sensitivity is most pronounced for the probe
spins with transverse magnetic anisotropy.",2108.11243v2
2021-06-21,Resonant Measurement of Non-Reorientable Spin-Orbit Torque from a Ferromagnetic Source Layer Accounting for Dynamic Spin Pumping,"Using a multilayer structure containing (cobalt detector layer)/(copper
spacer)/(Permalloy source layer), we show experimentally how the
non-reorientable spin-orbit torque generated by the Permalloy source layer (the
component of spin-orbit torque that does not change when the Permalloy
magnetization is rotated) can be measured using spin-torque ferromagnetic
resonance (ST-FMR) with lineshape analysis. We find that dynamic spin pumping
between the magnetic layers exerts torques on the magnetic layers as large or
larger than the spin-orbit torques, so that if dynamic spin pumping is
neglected the result would be a large overestimate of the spin-orbit torque.
Nevertheless, the two effects can be separated by performing ST-FMR as a
function of frequency. We measure a non-reorientable spin torque ratio
$\xi_{\text{Py}} = 0.04 \pm 0.01$ for spin current flow from Permalloy through
an 8 nm Cu spacer to the Co, and a strength of dynamic spin pumping that is
consistent with previous measurements by conventional ferromagnetic resonance.",2106.11127v1
2024-01-22,Rogue waves and instability arising from long-wave-short-wave resonance beyond the integrable regime,"We consider instability and localized patterns arising from long wave-short
wave (LWSW) resonance in the non-integrable regime numerically. We study the
stability and instability of elliptic-function periodic waves with respect to
subharmonic perturbations, whose period is a multiple of the period of the
elliptic waves. We thus find the modulational instability (MI) of the
corresponding dnoidal waves. Upon varying parameters of dnoidal waves,
spectrally unstable ones can be transformed into stable states via the
Hamiltonian Hopf bifurcation. For snoidal waves, we find a transition of the
dominant instability scenario between the MI and instability with a bubble-like
spectrum. For cnoidal waves, we produce three variants of the MI. Evolution of
the unstable states is also considered, leading to formation of rogue waves on
top of the elliptic-wave and continuous-wave backgrounds.",2401.11959v1
2005-01-27,Transition from rotating waves to modulated rotating waves on the sphere,"We study non-resonant and resonant Hopf bifurcation of a rotating wave in
SO(3)-equivariant reaction-diffusion systems on a sphere. We obtained reduced
differential equations on so(3), the characterization of modulated rotating
waves obtained by Hopf bifurcation of a rotating wave, as well as results
regarding the resonant case. Our main tools are the equivariant center manifold
reduction and the theory of Lie groups and Lie algebras, especially for the
group SO(3) of all rigid rotations on a sphere.",0501492v1
1998-10-18,Simulation and analysis of electron cyclotron resonance discharges,"We describe in detail the method for Particle-in cell/Monte-Carlo simulation
of electron cyclotron resonance (ECR) discharges. In the simulation, electric
and magnetic fields are obtained by solving Maxwell equations, and electrons
and ions are accelerated by solving equations of motion. We consider two
different cases: (i) propagation of electromagnetic wave in the presence of a
constant external magnetic field; (ii) propagation of electromagnetic wave in
the presence of a linearly decreasing magnetic field which corresponds to a
realistic ECR discharge. The simulation results indicate that at the resonance
layer, the electrons are heated by the electromagnetic wave, and the incoming
wave amplitude is pronouncedly damped, with the wave hardly propagating through
the ECR layer.",9810033v1
2019-06-14,Identifying four wave resonant interactions in a surface gravity wave turbulence experiment,"The nonlinear dynamics of waves at the sea surface is believed to be ruled by
the Weak Turbulence framework. In order to investigate the nonlinear coupling
among gravity surface waves, we developed an experiment in the Coriolis
facility which is a 13-m diameter circular tank. An isotropic and statistically
stationary wave turbulence of average steepness of 10\% is maintained by two
wedge wave makers. The space and time resolved wave elevation is measured using
a stereoscopic technique. Wave-wave interactions are analyzed through third and
fourth order correlations. We investigate specifically the role of bound waves
generated by non resonant 3-wave coupling. Specifically, we implement a
space-time filter to separate the dynamics of free waves (i.e. following the
dispersion relation) from the bound waves. We observe that the free wave
dynamics causes weak resonant 4-wave correlations. A weak level of correlation
is actually the basis of the Weak Turbulence Theory. Thus our observations
support the use of the Weak Turbulence to model gravity wave turbulence as is
currently been done in the operational models of wave forecasting. Although in
the theory bound waves are not supposed to contribute to the energy cascade,
our observation raises the question of the impact of bound waves on dissipation
and thus on energy transfers as well.",1906.06385v1
1994-06-27,Quantum melting of the long-range antiferromagnetic order and spin-wave condensation in t-J-V model,"We consider two-dimensional t-J-V model. The wave function of the ground
state is constructed. We demonstrate that the doping by holes results in
condensation of the spin-waves, destruction of the long-range antiferromagnetic
order and formation of the gap in the spin-wave spectrum.",9406105v1
1993-08-22,Rotation Axis Variation Due To Spin Orbit Resonance,"Rotation axis variation due to spin orbit resonance: conference report;
keywords: planetary precession, rigid body, chaos, KAM, Arnold diffusion,
averaging, celestial mechanics, classical mechanics, large deviations",9308006v1
2014-11-14,Spin-orbit coupling and chaotic rotation for eccentric coorbital bodies,"The presence of a co-orbital companion induces the splitting of the well
known Keplerian spin-orbit resonances. It leads to chaotic rotation when those
resonances overlap.",1411.3950v1
2010-04-18,Spin Orbit Coupling and Spin Waves in Ultrathin Ferromagnets: The Spin Wave Rashba Effect,"We present theoretical studies of the influence of spin orbit coupling on the
spin wave excitations of the Fe monolayer and bilayer on the W(110) surface.
The Dzyaloshinskii-Moriya interaction is active in such films, by virtue of the
absence of reflection symmetry in the plane of the film. When the magnetization
is in plane, this leads to a linear term in the spin wave dispersion relation
for propagation across the magnetization. The dispersion relation thus assumes
a form similar to that of an energy band of an electron trapped on a
semiconductor surfaces with Rashba coupling active. We also show SPEELS
response functions that illustrate the role of spin orbit coupling in such
measurements. In addition to the modifications of the dispersion relations for
spin waves, the presence of spin orbit coupling in the W substrate leads to a
substantial increase in the linewidth of the spin wave modes. The formalism we
have developed applies to a wide range of systems, and the particular system
explored in the numerical calculations provides us with an illustration of
phenomena which will be present in other ultrathin ferromagnet/substrate
combinations.",1004.3066v1
2014-06-24,Oblique propagation of longitudinal waves in magnetized spin-1/2 plasmas: Independent evolution of spin-up and spin-down electrons,"We consider quantum plasmas of electrons and motionless ions. We describe
separate evolution of spin-up and spin-down electrons. We present corresponding
set of quantum hydrodynamic equations. We assume that plasmas are placed in an
uniform external magnetic field. We account different occupation of spin-up and
spin-down quantum states in equilibrium degenerate plasmas. This effect is
included via equations of state for pressure of each species of electrons. We
study oblique propagation of longitudinal waves. We show that instead of two
well-known waves (the Langmuir wave and the Trivelpiece--Gould wave), plasmas
reveal four wave solutions. New solutions exist due to both the separate
consideration of spin-up and spin-down electrons \textit{and} different
occupation of spin-up and spin-down quantum states in equilibrium state of
degenerate plasmas.",1406.6252v1
2021-10-05,Generation of Nonreciprocity of Gapless Spin Waves by Chirality Injection,"In chiral magnets with intrinsic inversion symmetry breaking, it has been
known that two spin waves moving in opposite directions can propagate at
different velocities, exhibiting a phenomenon called magnetochiral
nonreciprocity which allows for realizations of certain spin logic devices such
as a spin-wave diode. Here, we theoretically demonstrate that the spin-wave
nonreciprocity can occur without intrinsic bulk chirality in certain magnets
including easy-cone ferromagnets and easy-cone antiferromagnetic. Specifically,
we show that nonlocal injection of a spin current from proximate normal metals
to easy-cone magnets engenders a non-equilibrium chiral spin texture, on top of
which spin waves exhibit nonreciprocity proportional to the injected spin
current. One notable feature of the discovered nonreciprocal spin waves is its
gapless nature, which can lead to a large thermal rectification effect at
sufficiently low temperatures. We envision that nonlocal electric injection of
chirality into otherwise nonchiral magnets may serve as a versatile route to
realize electrically controllable magnetochiral phenomena in a wide class of
materials.",2110.01867v2
2023-09-10,Non-zero Integral Spin of Acoustic Vortices and Spin-orbit Interaction in Longitudinal Acoustics,"Spin and orbital angular momenta (AM) are of fundamental interest in wave
physics. Acoustic wave, as a typical longitudinal wave, has been well studied
in terms of orbital AM, but still considered unable to carry non-zero integral
spin AM or spin-orbital interaction in homogeneous media due to its spin-0
nature. Here we give the first self-consistent analytical calculations of spin,
orbital and total AM of guided vortices under different boundary conditions,
revealing that vortex field can carry non-zero integral spin AM. We also
introduce for acoustic waves the canonical-Minkowski and kinetic-Abraham AM,
which has aroused long-lasting debate in optics, and prove that only the former
is conserved with the corresponding symmetries. Furthermore, we present the
theoretical and experimental observation of the spin-orbit interaction of
vortices in longitudinal acoustics, which is thought beyond attainable in
longitudinal waves in the absence of spin degree of freedom. Our work provides
a solid platform for future studies of the spin and orbital AM of guided
acoustic waves and may open up a new dimension for acoustic vortex-based
applications such as underwater communications and object manipulations.",2309.04989v1
2012-03-22,Magnetic hour-glass dispersion and its relation to high-temperature superconductivity in iron-tuned Fe$_{1+y}$Te$_{0.7}$Se$_{0.3}$,"High-temperature superconductivity remains arguably the largest outstanding
enigma of condensed matter physics. The discovery of iron-based
high-temperature superconductors has renewed the importance of understanding
superconductivity in materials susceptible to magnetic order and fluctuations.
Intriguingly they show magnetic fluctuations reminiscent of the superconducting
(SC) cuprates, including a 'resonance' and an 'hour-glass' shaped dispersion,
which provide an opportunity to new insight to the coupling between spin
fluctuations and superconductivity. Here we report inelastic neutron scattering
data on Fe$_{1+y}$Te$_{0.7}$Se$_{0.3}$ using excess iron concentration to tune
between a SC ($y=0.02$) and a non-SC ($y=0.05$) ground states. We find
incommensurate spectra in both samples but discover that in the one that
becomes SC, a constriction towards a commensurate hourglass shape develop well
above $T_c$. Conversely a spin-gap and concomitant spectral weight shift happen
below $T_c$. Our results imply that the hourglass shaped dispersion is most
likely a pre-requisite for superconductivity, whereas the spin-gap and shift of
spectral weight are consequences of superconductivity. We explain this
observation by pointing out that an inwards dispersion towards the commensurate
wave-vector is needed for the opening of a spin gap to lower the magnetic
exchange energy and hence provide the necessary condensation energy for the SC
state to emerge.",1203.4974v2
2013-10-30,Ground state uniqueness of the twelve site RVB spin-liquid parent Hamiltonian on the kagome lattice,"Anderson's idea of a (short-ranged) resonating valence bond (RVB) spin liquid
has been the first ever proposal of what we now call a topologically ordered
phase. Since then, a wealth of exactly solvable lattice models have been
constructed that have topologically ordered ground states. For a long time,
however, it has been difficult to realize Anderson's original vision in such
solvable models, according to which the ground state has an unbroken SU(2) spin
rotational symmetry and is dominated by fluctuation of singlet bonds. The
kagome lattice is the simplest lattice geometry for which parent Hamiltonians
stabilizing a prototypical spin-1/2 short-ranged RVB wave function has been
constructed and strong evidence has been given that this state belongs to a
topological phase. The uniqueness of the desired RVB-type ground states has,
however, not been rigorously proven for the simplest possible such Hamiltonian,
which acts on 12 spins at a time. Rather, this uniqueness has been demonstrated
for a longer ranged (19-site) variant of this Hamiltonian by Schuch et al., via
making contact with powerful results for projected entangled-pair states. In
this paper, we extend this result to the 12-site Hamiltonian. Our result is
based on numerical studies on finite clusters, for which we demonstrate a
""ground state intersection property"" with implications for arbitrary system
size. We also review the relations between various constructions schemes for
RVB parent-Hamiltonians found in the literature.",1310.8000v1
2012-09-26,The Thomas-Fermi Quark Model: Non-Relativistic Aspects,"The first numerical investigation of non-relativistic aspects of the
Thomas-Fermi (TF) statistical multi-quark model is given. We begin with a
review of the traditional TF model without an explicit spin interaction and
find that the spin splittings are too small in this approach. An explicit spin
interaction is then introduced which entails the definition of a generalized
spin ""flavor"". We investigate baryonic states in this approach which can be
described with two inequivalent wave functions; such states can however apply
to multiple degenerate flavors. We find that the model requires a spatial
separation of quark flavors, even if completely degenerate. Although the TF
model is designed to investigate the possibility of many-quark states, we find
surprisingly that it may be used to fit the low energy spectrum of almost all
ground state octet and decuplet baryons. The charge radii of such states are
determined and compared with lattice calculations and other models. The low
energy fit obtained allows us to extrapolate to the six-quark doubly strange
{\it H}-dibaryon state, flavor symmetric strange states of higher quark content
and possible six quark nucleon-nucleon resonances. The emphasis here is on the
{\it systematics} revealed in this approach. We view our model as a versatile
and convenient tool for quickly assessing the characteristics of new, possibly
bound, particle states of higher quark number content.",1209.6093v2
2018-08-16,Pressure-induced collapse of spin-orbital Mott state in the hyperhoneycomb iridate $β$-Li$_2$IrO$_3$,"Hyperhoneycomb iridate $\beta$-Li$_2$IrO$_3$ is a three-dimensional analogue
of two-dimensional honeycomb iridates, such as $\alpha$-Li$_2$IrO$_3$, which
recently appeared as another playground for the physics of Kitaev-type spin
liquid. $\beta$-Li$_2$IrO$_3$ shows a non-collinear spiral ordering of
spin-orbital-entangled $J_{\rm eff}$ = 1/2 moments at low temperature, which is
known to be suppressed under a pressure of $\sim$2 GPa. With further increase
of pressure, a structural transition is observed at $P_{\rm S}$ $\sim$ 4 GPa at
room temperature. Using the neutron powder diffraction technique, the crystal
structure in the high-pressure phase of $\beta$-Li$_2$IrO$_3$ above $P_{\rm S}$
was refined, which indicates the formation of Ir$_2$ dimers on the zig-zag
chains, with the Ir-Ir distance even shorter than that of metallic Ir. We argue
that the strong dimerization stabilizes the bonding molecular orbital state
comprising the two local $d_{zx}$-orbitals on the Ir-O$_2$-Ir bond plane, which
conflicts with the equal superposition of $d_{xy}$-, $d_{yz}$- and $d_{zx}$-
orbitals in the $J_{\rm eff}$ = 1/2 wave function produced by strong spin-orbit
coupling. The results of resonant inelastic x-ray scattering (RIXS)
measurements and the electronic structure calculations are fully consistent
with the collapse of the $J_{\rm eff}$ = 1/2 state. A subtle competition of
various electronic phases is universal in honeycomb-based Kitaev materials.",1808.05494v1
2001-12-19,Degeneracy of the ground-state of antiferromagnetic spin-1/2 Hamiltonians,"In the first part of this paper, the extension of the Lieb-Schultz-Mattis
theorem to dimensions larger than one is discussed. A counter example to the
original formulation of Lieb-Schultz-Mattis and Affleck is exhibited and a more
precise statement is formulated. The degeneracy of the ground-state in symmetry
breaking phases with long-range order is analyzed. The second and third parts
of the paper concern resonating valence-bond (RVB) spin liquids. In these
phases the relationship between various authors approaches: Laughlin-Oshikawa,
Sutherland, Rokhsar and Kivelson, Read and Chakraborty and the
Lieb-Schultz-Mattis-Affleck proposal is studied. The deep physical relation
between the degeneracy property and the absence of stiffness is explained and
illustrated numerically. A new conjecture is formed concerning the absolute
absence of sensitivity of the spin liquid ground-states to any twist of the
boundary conditions (thermodynamic limit). In the third part of the paper the
relations between the quantum numbers of the degenerate multiplets of the spin
liquid phases are obtained exactly. Their relationship with a topological
property of the wave functions of the low lying levels of this spin liquid
phase is emphasized. In spite of the degeneracy of the ground-state, we explain
why these phases cannot exhibit spontaneous symmetry breaking.",0112360v1
2009-02-01,Neutron Studies of the Iron-based Family of High TC Magnetic Superconductors,"We review neutron scattering investigations of the crystal structures,
magnetic structures, and spin dynamics of the iron-based RFe(As,P)O (R=La, Ce,
Pr, Nd), (Ba,Sr,Ca)Fe2As2, and Fe1+x(Te-Se) systems. On cooling from room
temperature all the undoped materials exhibit universal behavior, where a
tetragonal-to-orthorhombic/monoclinic structural transition occurs, below which
the systems become antiferromagnets. For the first two classes of materials the
magnetic structure within the a-b plane consists of chains of parallel Fe spins
that are coupled antiferromagnetically in the orthogonal direction, with an
ordered moment typically less than one Bohr magneton. Hence these are itinerant
electron magnets, with a spin structure that is consistent with Fermi-surface
nesting and a very energetic spin wave bandwidth ~0.2 eV. With doping, the
structural and magnetic transitions are suppressed in favor of
superconductivity. Magnetic correlations are observed in the superconducting
regime, with a magnetic resonance that follows the superconducting order
parameter just like the cuprates. The rare-earth moments order
antiferromagnetically at low T like conventional magnetic-superconductors.
Pressure in CaFe2As2 transforms the system from a magnetically ordered
orthorhombic material to a collapsed non-magnetic tetragonal system. Tetragonal
Fe1+xTe transforms to a low T monoclinic structure at small x that changes to
orthorhombic at larger x, which is accompanied by a crossover from commensurate
to incommensurate magnetic order. Se doping suppresses the magnetic order.",0902.0091v2
2014-01-27,Direct determination of exchange parameters in Cs2CuBr4 and Cs2CuCl4: high-field ESR studies,"Spin-1/2 Heisenberg antiferromagnets Cs$_2$CuCl$_4$ and Cs$_2$CuBr$_4$ with
distorted triangular-lattice structures are studied by means of electron spin
resonance spectroscopy in magnetic fields up to the saturation field and above.
In the magnetically saturated phase, quantum fluctuations are fully suppressed,
and the spin dynamics is defined by ordinary magnons. This allows us to
accurately describe the magnetic excitation spectra in both materials and,
using the harmonic spin-wave theory, to determine their exchange parameters.
The viability of the proposed method was proven by applying it to
Cs$_2$CuCl$_4$, yielding $J/k_B=4.7(2)$ K, $J'/k_B=1.42(7)$ K [$J'/J\simeq
0.30$] and revealing good agreement with inelastic neutron-scattering results.
For the isostructural Cs$_2$CuBr$_4$, we obtain $J/k_B=14.9(7)$ K,
$J'/k_B=6.1(3)$ K, [$J'/J\simeq 0.41$], providing exact and conclusive
information on the exchange couplings in this frustrated spin system.",1401.6793v2
2017-08-16,Magneto Acoustic Spin Hall Oscillators,"This paper introduces a novel oscillator that combines the tunability of spin
Hall-driven nano oscillators with the high quality factor (Q) of high overtone
bulk acoustic wave resonators (HBAR), integrating both reference and tunable
oscillators on the same chip with CMOS. In such magneto acoustic spin Hall
(MASH) oscillators, voltage oscillations across the magnetic tunnel junction
(MTJ) that arise from a spin-orbit torque (SOT) are shaped by the transmission
response of the HBAR that acts as a multiple peak-bandpass filter and a delay
element due to its large time constant, providing delayed feedback. The
filtered voltage oscillations can be fed back to the MTJ via a) strain, b)
current, or c) magnetic field. We develop a SPICE-based circuit model by
combining experimentally benchmarked models including the stochastic
Landau-Lifshitz-Gilbert (sLLG) equation for magnetization dynamics and the
Butterworth Van Dyke (BVD) circuit for the HBAR. Using the self-consistent
model, we project up to $\sim$ 50X enhancement in the oscillator linewidth with
Q reaching up to 52825 at 3 GHz, while preserving the tunability by locking the
STNO to the nearest high Q peak of the HBAR. We expect that our results will
inspire MEMS-based solutions to spintronic devices by combining attractive
features of both fields for a variety of applications.",1708.04735v2
2018-06-25,Fermi surface pockets in electron-doped iron superconductor by Lifshitz transition,"The Fermi surface pockets that lie at the corner of the two-iron Brillouin
zone in heavily electron-doped iron selenide superconductors are accounted for
by an extended Hubbard model over the square lattice of iron atoms that
includes the principal 3d xz and 3d yz orbitals. At half filling, and in the
absence of intra-orbital next-nearest neighbor hopping, perfect nesting between
electron-type and hole-type Fermi surfaces at the the center and at the corner
of the one-iron Brillouin zone is revealed. It results in hidden magnetic order
in the presence of magnetic frustration within mean field theory. An
Eliashberg-type calculation that includes spin-fluctuation exchange finds that
the Fermi surfaces undergo a Lifshitz transition to electron/hole Fermi surface
pockets centered at the corner of the two-iron Brillouin zone as on-site
repulsion grows strong. In agreement with angle-resolved photoemission
spectroscopy on iron selenide high-temperature superconductors, only the two
electron-type Fermi surface pockets remain after a rigid shift in energy of the
renormalized band structure by strong enough electron doping. At the limit of
strong on-site repulsion, a spin-wave analysis of the hidden-magnetic-order
state finds a ""floating ring"" of low-energy spin excitations centered at the
checkerboard wavenumber (pi,pi). This prediction compares favorably with recent
observations of low-energy spin resonances around (pi,pi) in intercalated iron
selenide by inelastic neutron scattering.",1806.09322v2
2019-01-31,Fundamental Spin Interactions Underlying the Magnetic Anisotropy in the Kitaev Ferromagnet CrI$_3$,"We lay the foundation for determining the microscopic spin interactions in
two-dimensional (2D) ferromagnets by combining angle-dependent ferromagnetic
resonance (FMR) experiments on high quality CrI$_3$ single crystals with
theoretical modeling based on symmetries. We discover that the Kitaev
interaction is the strongest in this material with $K \sim -5.2$ meV, 25 times
larger than the Heisenberg exchange $J \sim -0.2$ meV, and responsible for
opening the $\sim$5 meV gap at the Dirac points in the spin-wave dispersion.
Furthermore, we find that the symmetric off-diagonal anisotropy $\Gamma \sim
-67.5$ $\mu$eV, though small, is crucial for opening a $\sim$0.3 meV gap in the
magnon spectrum at the zone center and stabilizing ferromagnetism in the 2D
limit. The high resolution of the FMR data further reveals a $\mu$eV-scale
quadrupolar contribution to the $S=3/2$ magnetism. Our identification of the
underlying exchange anisotropies opens paths toward 2D ferromagnets with higher
$T_\text{C}$ as well as magnetically frustrated quantum spin liquids based on
Kitaev physics.",1902.00077v2
2017-06-23,Competition between spin liquids and valence-bond order in the frustrated spin-$1/2$ Heisenberg model on the honeycomb lattice,"Using variational wave functions and Monte Carlo techniques, we study the
antiferromagnetic Heisenberg model with first-neighbor $J_1$ and
second-neighbor $J_2$ antiferromagnetic couplings on the honeycomb lattice. We
perform a systematic comparison of magnetically ordered and nonmagnetic states
(spin liquids and valence-bond solids) to obtain the ground-state phase
diagram. N\'eel order is stabilized for small values of the frustrating
second-neighbor coupling. Increasing the ratio $J_2/J_1$, we find strong
evidence for a continuous transition to a nonmagnetic phase at $J_2/J_1 \approx
0.23$. Close to the transition point, the Gutzwiller-projected uniform
resonating valence bond state gives an excellent approximation to the exact
ground-state energy. For $0.23 \lesssim J_2/J_1 \lesssim 0.4$, a gapless $Z_2$
spin liquid with Dirac nodes competes with a plaquette valence-bond solid. In
contrast, the gapped spin liquid considered in previous works has significantly
higher variational energy. Although the plaquette valence-bond order is
expected to be present as soon as the N\'eel order melts, this ordered state
becomes clearly favored only for $J_2/J_1 \gtrsim 0.3$. Finally, for $0.36
\lesssim J_2/J_1 \le 0.5$, a valence-bond solid with columnar order takes over
as the ground state, being also lower in energy than the magnetic state with
collinear order. We perform a detailed finite-size scaling and standard data
collapse analysis, and we discuss the possibility of a deconfined quantum
critical point separating the N\'eel antiferromagnet from the plaquette
valence-bond solid.",1706.07810v3
2021-08-02,The SMART protocol -- Pulse engineering of a global field for robust and universal quantum computation,"Global control strategies for arrays of qubits are a promising pathway to
scalable quantum computing. A continuous-wave global field provides decoupling
of the qubits from background noise. However, this approach is limited by
variability in the parameters of individual qubits in the array. Here we show
that by modulating a global field simultaneously applied to the entire array,
we are able to encode qubits that are less sensitive to the statistical scatter
in qubit resonance frequency and microwave amplitude fluctuations, which are
problems expected in a large scale system. We name this approach the SMART
(Sinusoidally Modulated, Always Rotating and Tailored) qubit protocol. We show
that there exist optimal modulation conditions for qubits in a global field
that robustly provide improved coherence times. We discuss in further detail
the example of spins in silicon quantum dots, in which universal one- and
two-qubit control is achieved electrically by controlling the spin-orbit
coupling of individual qubits and the exchange coupling between spins in
neighbouring dots. This work provides a high-fidelity qubit operation scheme in
a global field, significantly improving the prospects for scalability of
spin-based quantum computer architectures.",2108.00776v3
2022-01-05,Floquet-Weyl semimetals generated by an optically resonant interband-transition,"Floquet-Weyl semimetals (FWSMs) generated by irradiation of a continuous-wave
laser with left-hand circular polarization (rotating in counterclockwise sense
with time) on the group II-V narrow gap semiconductor Zn$_3$As$_2$ are
theoretically investigated, where the frequency of the laser is set nearly {\it
resonant} with a band gap of the crystal. It is found that the excitation of
the crystal by such a laser induce two types of FWSM phases that differ
absolutely in characters. To be specific, the associated two pairs of Weyl
points are stably formed by band touching between Floquet sidebands ascribable
to a valence band labeled as $J_z=\pm3/2$ and a conduction band labeled as
$J_z=\pm 1/2$, where $J_z$ represents the $z$-component of total angular
momentum quantum number of $\Gamma$-point and a double sign corresponds. Here,
one FWSM state composed of the up-spin Floquet sidebands relevant to $J_z=3/2$
and $1/2$ shows almost quadratic band-touching in the vicinity of the
associated pair of Weyl points, while the other FWSM state composed of the
down-spin Floquet sidebands relevant to $J_z=-3/2$ and $-1/2$ shows linear
band-touching. Further, it is revealed that both up-spin and down-spin
sidebands host nontrivial two-dimensional surface states that are pinned to the
respective pairs of the Weyl points. Both surface states also show different
energy dispersions and physical properties. More detailed discussion is made in
the text on the origin of the above findings, chirality of the FWSM phases,
alteration of topological order, laser-induced magnetic properties, and so on.",2201.01578v2
2023-10-17,Low-energy electronic interactions in ferrimagnetic Sr2CrReO6 thin films,"We reveal in this study the fundamental low-energy landscape in the
ferrimagnetic Sr2CrReO6 double perovskite and describe the underlying
mechanisms responsible for the three low-energy excitations below 1.4 eV. Based
on resonant inelastic x-ray scattering and magnetic dynamics calculations, and
experiments collected from both Sr2CrReO6 powders and epitaxially strained thin
films, we reveal a strong competition between spin-orbit coupling, Hund's
coupling, and the strain-induced tetragonal crystal field. We also demonstrate
that a spin-flip process is at the origin of the lowest excitation at 200 meV,
and we bring insights into the predicted presence of orbital ordering in this
material. We study the nature of the magnons through a combination of ab initio
and spin-wave theory calculations, and show that two nondegenerate magnon bands
exist and are dominated either by rhenium or chromium spins. The rhenium band
is found to be flat at about 200 meV ($\pm$25 meV) through X-L-W-U
high-symmetry points and is dispersive toward $\Gamma$",2310.11585v1
2023-12-06,Spontaneous Chirality Flipping in an Orthogonal Spin-Charge Ordered Topological Magnet,"The asymmetric distribution of chiral objects with opposite chirality is of
great fundamental interests ranging from molecular biology to particle physics.
In quantum materials, chiral states can build on inversion-symmetry-breaking
lattice structures or emerge from spontaneous magnetic ordering induced by
competing interactions. Although the handedness of a chiral state can be
changed through external fields, a spontaneous chirality flipping has yet to be
discovered. In this letter, we present experimental evidence of chirality
flipping via changing temperature in a topological magnet EuAl$_4$, which
features orthogonal spin and charge density waves (SDW/CDW). Using circular
dichroism of Bragg peaks in the resonant magnetic x-ray scattering, we find
that the chirality of the helical SDW flips through a first order phase
transition with modified SDW wavelength. Intriguingly, we observe that the CDW
couples strongly with the SDW and displays a rare
commensurate-to-incommensurate transition at the chirality flipping
temperature. Combining with first principles calculations and angle resolved
photoemission spectroscopy, we establish the Fermi surface origin of the
helical SDW with intertwined spin, charge, and lattice degrees of freedom in
EuAl$_4$. Our results reveal an unprecedented spontaneous chirality flipping
and lays the groundwork for a new functional manipulation of chirality through
momentum dependent spin-charge-lattice interactions.",2312.03684v2
2003-09-30,Recent Progress of the Low-Dimensional Spin-Wave Theory,"A modified spin-wave theory is developed and applied to low-dimensional
quantum magnets. Double-peaked specific heat for one-dimensional ferrimagnets,
nuclear spin-lattice relaxation in ferrimagnetic chains and clusters, and
thermal behavior of Haldane-gap antiferromagnets are described within the
scheme. Mentioning other bosonic and fermionic representations as well, we
demonstrate that spin waves are still effective in low dimensions.",0310004v1
2003-03-20,Spin waves in La_2CuO_4: band structure and correlation effects,"We calculate the antiferromagnetic spin wave dispersion in the half-filled
(electronic density n=1) Hubbard model for a two-dimensional square lattice,
using the random phase approximation (RPA) in a broken symmetry (spin density
wave) ground state. Our results for the spin wave dispersion, \omega(\vec q),
are compared with high-resolution inelastic neutron scattering performed on
La_2CuO$_4. The effects of different band structures and different values of
the on-site Coulomb interaction on the spin wave spectrum is studied.
Particular attention is put on the high energy dispersion values
\omega(\pi/2,\pi/2) and \omega(0,\pi).",0303409v1
2003-08-14,On the motion of spinning test particles in plane gravitational waves,"The Mathisson-Papapetrou-Dixon equations for a massive spinning test particle
in plane gravitational waves are analysed and explicit solutions constructed in
terms of solutions of certain linear ordinary differential equations. For
harmonic waves this system reduces to a single equation of Mathieu-Hill type.
In this case spinning particles may exhibit parametric excitation by
gravitational fields. For a spinning test particle scattered by a gravitational
wave pulse, the final energy-momentum of the particle may be related to the
width, height, polarisation of the wave and spin orientation of the particle.",0308042v1
2002-03-02,Spin waves in the magnetized plasma of a supernova and its excitation by neutrino fluxes,"The spin effects on electromagnetic waves in a strongly magnetized plasma
with rare collisions is considered with the help of relativistic kinetic
equations, which takes into account the electron spin dynamics in the
selfconsistent electric and magnetic fields. It is shown that for
electromagnetic waves propagating almost perpendicular to ambient magnetic
field the spin effects become essential in the vicinity of electron
gyrofrequency and the corresponding wave dispersion and growth rate of the
electromagnetic spin waves in the presence of intense quasi monoenergetic
fluxes of neutrino is determined.",0203020v1
2009-01-18,Generation of pulse trains by current-controlled magnetic mirrors,"The evolution of a spin-wave packet trapped between two direct
current-carrying wires placed on the surface of a ferrite film is observed by
Brillouin light scattering. The wires act as semi-transparent mirrors confining
the packet. Because the spin-wave energy partially passes through these
mirrors, trains of spin-wave packets are generated outside the trap. A
numerical model of this process is presented and applied to the case when the
current in the wires is dynamically controlled. This dynamical control of the
mirror reflectivity provides new functionalities interesting for the field of
spin-wave logic like that of a spin-wave memory cell.",0901.2704v1
2012-11-06,Spin Wave Scattering in Ferromagnetic Cross,"Spin wave scattering in the right angle ferromagnetic cross was measured.
Shape anisotropy defined magnetization ground states at zero biasing magnetic
fields. Scattering of the spin waves in the center of ferromagnetic cross is
strongly dependent on the amplitude and angle of the biasing magnetic field.
Micromagnetic simulations indicate that low in-plane biasing magnetic fields
rotate the magnetization of the cross center while the arms stay axially
magnetized due to the shape anisotropy. We discuss effect of biasing magnetic
fields on the spin wave scattering and approaches to an effective spin wave
switch based on the fabricated structure.",1211.1259v1
2014-08-14,Design of a spin-wave majority gate employing mode selection,"The design of a microstructured, fully functional spin-wave majority gate is
presented and studied using micromagnetic simulations. This all-magnon logic
gate consists of three-input waveguides, a spin-wave combiner and an output
waveguide. In order to ensure the functionality of the device, the output
waveguide is designed to perform spin-wave mode selection. We demonstrate that
the gate evaluates the majority of the input signals coded into the spin-wave
phase. Moreover, the all-magnon data processing device is used to perform logic
AND-, OR-, NAND- and NOR- operations.",1408.3235v1
2016-04-29,Extraordinary waves in two dimensional electron gas with separate spin evolution and Coulomb exchange interaction,"Hydrodynamics analysis of waves in two-dimensional degenerate electron gas
with the account of separate spin evolution is presented. The transverse
electric field is included along with the longitudinal electric field. The
Coulomb exchange interaction is included in the analysis. In contrast with the
three-dimensional plasma-like mediums the contribution of the transverse
electric field is small. We show the decrease of frequency of both the
extraordinary (Langmuir) wave and the spin-electron acoustic wave due to the
exchange interaction. Moreover, spin-electron acoustic wave has negative
dispersion at the relatively large spin-polarization. Corresponding dispersion
dependencies are presented and analyzed.",1604.08902v1
2018-03-08,First-principles study of spin-wave dispersion in Sm(Fe$_{1-x}$Co$_{x}$)$_{12}$,"We present spin-wave dispersion in Sm(Fe$_{1-x}$Co$_x$)$_{12}$ calculated
based on first-principles. Anisotropy in the lowest branch of the spin-wave
dispersion around the $\Gamma$ point is discussed. Spin-waves propagate more
easily along $a^*$-axis than along $c^*$-axis, especially in SmFe$_{12}$. We
also compare values of the spin-wave stiffness with those obtained from an
experiment. The calculated values are in good agreement with the experimental
values.",1803.03165v3
2020-04-17,Collective coordinate study of spin wave emission from dynamic domain wall,"We study theoretically the spin wave emission from a moving domain wall in a
ferromagnet. Introducing a deformation mode describing a modulation of the wall
thickness in the collective coordinate description, we show that thickness
variation couples to the spin wave linearly and induces spin wave emission. The
dominant emitted spin wave turns out to be polarized in the out-of wall plane
($\phi$)-direction. The emission contributes to the Gilbert damping parameter
proportional to $\hbar\omega_\phi/K$, the ratio of the angular frequency
$\omega_\phi$ of $\phi$ and the easy-axis anisotropy energy $K$.",2004.08082v1
2010-04-26,Selective spatial damping of propagating kink waves due to resonant absorption,"There is observational evidence of propagating kink waves driven by
photospheric motions. These disturbances, interpreted as kink
magnetohydrodynamic (MHD) waves are attenuated as they propagate upwards in the
solar corona. In this paper we show that resonant absorption provides a simple
explanation to the spatial damping of these waves. Kink MHD waves are studied
using a cylindrical model of solar magnetic flux tubes which includes a
non-uniform layer at the tube boundary. Assuming that the frequency is real and
the longitudinal wavenumber complex, the damping length and damping per
wavelength produced by resonant absorption are analytically calculated. The
damping length of propagating kink waves due resonant absorption is a
monotonically decreasing function of frequency. For kink waves with low
frequencies the damping length is exactly inversely proportional to frequency
and we denote this as the TGV relation. When moving to high frequencies the TGV
relation continues to be an exceptionally good approximation of the actual
dependency of the damping length on frequency. This dependency means that
resonant absorption is selective as it favours low frequency waves and can
efficiently remove high frequency waves from a broad band spectrum of kink
waves. It is selective as the damping length is inversely proportional to
frequency so that the damping becomes more severe with increasing frequency.
This means that radial inhomogeneity can cause solar waveguides to be a natural
low-pass filter for broadband disturbances. Hence kink wave trains travelling
along, e.g., coronal loops, will have a greater proportion of the high
frequency components dissipated lower down in the atmosphere. This could have
important consequences with respect to the spatial distribution of wave heating
in the solar atmosphere.",1004.4468v1
2013-02-24,Electron spin resonance in a dilute magnon gas as a probe of magnon scattering resonances,"We study the electron spin resonance in a dilute magnon gas that is realized
in a ferromagnetic spin system at low temperature. A quantum cluster expansion
is developed to show that the frequency shift of the single-magnon peak changes
its sign and the linewidth reaches its maximum across a scattering resonance
between magnons. Such characteristic behaviors are universal and can be used to
experimentally locate the two-magnon resonance when an external parameter such
as pressure is varied. Future achievement of the two-magnon resonance may have
an impact comparable to the Feshbach resonance in ultracold atoms and will open
up a rich variety of strongly correlated physics such as the recently proposed
Efimov effect in quantum magnets. We also suggest how the emergence of an
Efimov state of three magnons and its binding energy may be observed with the
electron spin resonance.",1302.5908v2
2023-12-22,Dynamical structures associated with high-order and secondary resonances in the spin-orbit problem,"In our Solar system, spin-orbit resonances are common under Sun--planet,
planet--satellite and binary asteroid configurations. In this work, high-order
and secondary spin-orbit resonances are investigated by taking numerical and
analytical approaches. Poincar\'e sections as well as two types of dynamical
maps are produced, showing that there are complicated structures in the phase
space. To understand numerical structures, we adopt the theory of perturbative
treatments to formulate resonant Hamiltonian for describing spin-orbit
resonances. Results show that there is an excellent agreement between
analytical and numerical structures. It is concluded that the main V-shape
structure arising in the parameter space $(\dot\theta,\alpha)$ is sculpted by
the synchronous primary resonance, those minute structures inside the V-shape
region are dominated by secondary resonances and those structures outside the
V-shape region are governed by high-order resonances. At last, the analytical
approach is applied to binary asteroid systems (65803) Didymos and (4383)
Suruga to reveal their phase-space structures.",2312.14413v1
2023-03-20,Ab initio calculation of the spectrum of Feshbach resonances in NaLi + Na collisions,"We present a combined experimental and theoretical study of the spectrum of
magnetically tunable Feshbach resonances in NaLi $(a^3\Sigma^+)$ $+$ Na
collisions. In the accompanying paper, we observe experimentally 8 and 17
resonances occur between $B=0$ and $1400$~G in upper and lower spin-stretched
states, respectively. Here, we perform ab initio calculations of the NaLi $+$
Na interaction potential and describe in detail the coupled-channel scattering
calculations of the Feshbach resonance spectrum. The positions of the
resonances cannot be predicted with realistic uncertainty in the
state-of-the-art ab initio potential, but our calculations yield a typical
number of resonances that is in near-quantitative agreement with experiment. We
show that the main coupling mechanism results from spin-rotation and spin-spin
couplings in combination with the anisotropic atom-molecule interaction. The
calculations furthermore explain the qualitative difference between the numbers
of resonances in either spin state.",2303.10940v2
2022-11-06,Interpretation of spin-wave modes in Co/Ag nanodot arrays probed by broadband ferromagnetic resonance,"We present a detailed investigation of the magnetization dynamics in Co/Ag
nanodots, which due to their size can support standing spin-wave (SSW) modes
with complex spectral responses. To interpret the experimentally measured
broadband vector network analyzer ferromagnetic resonance data, we compare the
spectra of the nanoarray structure with those of the unpatterned Co/Ag film of
identical thickness, which serves as a baseline for obtaining the general
magnetic parameters of the system. Using a novel frequency domain, matrix-free
simulation method of the dynamic response, we identify the nature of the
excitation modes, which allows us to assess the boundary conditions for the
nanodots. We find an excellent agreement between the calculated and
experimental values for the frequencies of the fundamental (uniform-like) (011)
mode. The existence of an edge-localized mode in the experiment has been
confirmed and fits very well with theory and micromagnetic simulations, having
the form of a flapping mode at the extrema of the nanodot in one of the
in-plane directions. Its frequency is below the fundamental mode's frequency
and has been shown to be a consequence of the imaginary wave vector for such
localized SSW modes. Higher order SSW modes can be generated from the theory,
which allows us to find a probable mode number for the second bulk SSW (201 or
221 or 131), which lies at frequencies above the fundamental mode.",2211.03042v5
2017-06-09,Spin-wave analysis for Kagome-triangular spin system and coupled spin tubes: low-energy excitation for the cuboc order,"The coupled spin tube system, which is equivalent to a stacked
Kagome-triangular spin system, exhibits the cuboc order -- a non-coplanar spin
order with a twelve-sublattice structure accompanying spontaneous breaking of
the translational symmetry -- in the Kagome-triangular plane. On the basis of
the spin-wave theory, we analyze spin-wave excitations of the planar
Kagome-triangular spin system, where the geometric phase characteristic to the
cuboc spin structure emerges. We further investigate spin-wave excitations and
dynamical spin structure factors for the coupled spin tubes, assuming the
staggered cuboc order.",1706.02879v2
2018-01-08,Spin-resolved inelastic electron scattering by spin waves in noncollinear magnets,"Topological non-collinear magnetic phases of matter are at the heart of many
proposals for future information nanotechnology, with novel device concepts
based on ultra-thin films and nanowires. Their operation requires understanding
and control of the underlying dynamics, including excitations such as
spin-waves. So far, no experimental technique has attempted to probe large
wave-vector spin-waves in non-collinear low-dimensional systems. In this work,
we explain how inelastic electron scattering, being suitable for investigations
of surfaces and thin films, can detect the collective spin-excitation spectra
of non-collinear magnets. To reveal the particularities of spin-waves in such
non-collinear samples, we propose the usage of spin-polarized
electron-energy-loss spectroscopy augmented with a spin-analyzer. With the
spin-analyzer detecting the polarization of the scattered electrons, four
spin-dependent scattering channels are defined, which allow to filter and
select specific spin-wave modes. We take as examples a topological non-trivial
skyrmion lattice, a spin-spiral phase and the conventional ferromagnet. Then we
demonstrate that, counter-intuitively and in contrast to the ferromagnetic
case, even non spin-flip processes can generate spin-waves in non-collinear
substrates. The measured dispersion and lifetime of the excitation modes permit
to fingerprint the magnetic nature of the substrate.",1801.02542v2
2006-06-30,A variational coupled-cluster study of magnon-density-wave excitations in quantum antiferromagnets,"We extend recently proposed variational coupled-cluster method to describe
excitation states of quantum antiferromagnetic bipartite lattices. We reproduce
the spin-wave excitations (i.e., magnons with spin $\pm 1$). In addition, we
obtain a new, spin-zero excitation (magnon-density waves) which has been
missing in all existing spin-wave theories. Within our approximation, this
magnon-density-wave excitation has a nonzero energy gap in a cubic lattice and
is gapless in a square lattice, similar to those charge-density-wave
excitations (plasmons) in quantum electron gases.",0606813v2
2011-03-11,Interference of coherent spin waves in micron-sized ferromagnetic waveguides,"We present experimental observations of the interference of spin-wave modes
propagating in opposite directions in micron-sized NiFe-waveguides. To monitor
the local spin-wave intensity distribution and phase of the formed interference
pattern, we use Brillouin light scattering microscopy. The two-dimensional
spin-wave intensity map can be understood by considering the interference of
several waveguide eigenmodes with different wavevectors quantized across the
width of the stripe. The phase shows a transition from linear dependence on the
space coordinate near the antennas characteristic for propagating waves to
discrete values in the center region characteristic for standing waves.",1103.2248v1
2016-06-29,Observation of resonant interactions among surface gravity waves,"We experimentally study resonant interactions of oblique surface gravity
waves in a large basin. Our results strongly extend previous experimental
results performed mainly for perpendicular or collinear wave trains. We
generate two oblique waves crossing at an acute angle, while we control their
frequency ratio, steepnesses and directions. These mother waves mutually
interact and give birth to a resonant wave whose properties (growth rate,
resonant response curve and phase locking) are fully characterized. All our
experimental results are found in good quantitative agreement with four-wave
interaction theory with no fitting parameter. Off-resonance experiments are
also reported and the relevant theoretical analysis is conducted and validated.",1606.09009v3
2018-03-23,A Novel Approach to Resonant Absorption of the Fast MHD Eigenmodes of a Coronal Arcade,"The arched field lines forming coronal arcades are often observed to undulate
as magnetohydrodynamic (MHD) waves propagate both across and along the magnetic
field. These waves are most likely a combination of resonantly coupled fast
magnetoacoustic waves and Alfv\'en waves. The coupling results in resonant
absorption of the fast waves, converting fast wave energy into Alfv\'en waves.
The fast eigenmodes of the arcade have proven difficult to compute or derive
analytically, largely because of the mathematical complexity that the coupling
introduces. When a traditional spectral decomposition is employed, the discrete
spectrum associated with the fast eigenmodes is often subsumed into the
continuous Alfv\'en spectrum. Thus fast eigenmodes, become collective modes or
quasi-modes. Here we present a spectral decomposition that treats the
eigenmodes as having real frequencies but complex wavenumbers. Using this
procedure we derive dispersion relations, spatial damping rates, and
eigenfunctions for the resonant, fast eigenmodes of the arcade. We demonstrate
that resonant absorption introduces a fast mode that would not exist otherwise.
This new mode is heavily damped by resonant absorption, only travelling a few
wavelengths before losing most of its energy.",1803.08948v1
2020-11-06,Design of ultra-high gain optical micro-amplifiers via smart non-linear wave mixing,"Optical amplification of the input wave by mixing the pump wave within a
nonlinear interaction medium offers high gain for a variety of applications. In
real life studies, the interaction mediums which allow the optical
amplification of the input wave have many resonance frequencies. However, the
computational expense for tuning the pump frequency to yield the optical
amplification of the input wave increases with the number of resonance
frequencies within the interaction mediums. Here, we present a Fletcher-Reeves
based algorithm for parametric amplification in micro-resonators having
multiple resonance frequencies. Using our novel mathematical formulations, we
obtained a gain of 4.7x107 for the input wave at 640 THz and a gain of 1.5x108
for the input wave at 100 THz within the micro-resonators. Moreover, the
performance of our algorithm is verified by the well know mathematical
expression, and we achieved more than 99% accuracy in computation of optical
amplification. To our knowledge, this is the first study where Fletcher-Reeves
algorithm is used for the parametric amplification. Our methodology can be
accompanied to design optical parametric amplifiers for applications of
high-speed optical communications, photonic circuits, and ultrafast lasers.",2011.03592v1
2020-01-15,Surface waves from flexural and compressional resonances of beams,"We present a three-dimensional model describing the propagation of elastic
waves in a soil substrate supporting an array of cylindrical beams experiencing
flexural and compressional resonances. The resulting surface waves are of two
types. In the sagittal plane, hybridized Rayleigh waves can propagate except
within bandgaps resulting from a complex interplay between flexural and
compressional resonances. We exhibit a wave decoupled from the hybridized
Rayleigh wave which is the elastic analogue of electromagnetic spoof plasmon
polaritons. This wave with displacements perpendicular to the sagittal plane is
sensitive only to flexural resonances. Similar, yet quantitatively different,
physics is demonstrated in a two-dimensional setting involving resonances of
plates.",2001.06304v1
2010-03-29,"From (pi, 0) magnetic order to superconductivity with (pi, pi) magnetic resonance in Fe1.02(Te1-xSex)","The iron chalcogenide Fe1+y(Te1-xSex) is structurally the simplest of the
Fe-based superconductors. Although the Fermi surface is similar to iron
pnictides, the parent compound Fe1+yTe exhibits antiferromagnetic order with
in-plane magnetic wave-vector (pi, 0). This contrasts the pnictide parent
compounds where the magnetic order has an in-plane magnetic wave-vector (pi,
pi) that connects hole and electron parts of the Fermi surface. Despite these
differences, both the pnictide and chalcogenide Fe-superconductors exhibit
superconducting spin resonances around (pi, pi), suggesting a common symmetry
for their superconducting order parameter. A central question in this
burgeoning field is therefore how (pi, pi) superconductivity can emerge from a
(pi, 0) magnetic instability. Here, we report that the magnetic soft mode
evolving from the (pi, 0)-type magnetic long-range order is associated with
weak charge carrier localization. Bulk superconductivity occurs only as the
magnetic mode at (pi, pi) becomes dominant upon doping. Our results suggest a
common magnetic origin for superconductivity in iron chalcogenide and pnictide
superconductors.",1003.5647v1
2016-09-20,Scaling in global tidal dissipation of the Earth-Moon system,"The Moon migrated to $r_{\leftmoon}\simeq3.8\times10^{10}$ cm over a
characteristic time $r/v=10^{10}$ Gyr by tidal interaction with the Earth's
oceans at a present velocity of $v=3.8$ cm yr$^{-1}$. We derive scaling of
global dissipation that covers the entire history over the past 4.52 Gyr.
Off-resonance tidal interactions at relatively short tidal periods in the past
reveal the need for scaling {with amplitude}. The global properties of the
complex spatio-temporal dynamics and dissipation in broad spectrum ocean waves
is modeled by damping $\epsilon = h F/(2Q_0)$, where $h$ is the tidal wave
amplitude, $F$ is the tidal frequency, and $Q_0$ is the $Q$-factor at the
present time. It satisfies $Q_0\simeq 14$ for consistency of migration time and
age of the Moon consistent with observations for a near-resonance state today.
It shows a startingly fast eviction of the Moon from an unstable
near-synchronous orbit close to the Roche limit, probably in a protolunar disk.
Rapid spin down of the Earth from an intial $\sim30\%$ of break-up by the Moon
favored early formation of a clement global climate. Our theory suggests moons
may be similarly advantageous to potentially habitable exoplanets.",1609.07474v1
2018-01-23,Semidiurnal thermal tides in asynchronously rotating hot Jupiters,"Thermal tides can torque the atmosphere of hot Jupiters into asynchronous
rotation, while these planets are usually assumed to be locked into spin-orbit
synchronization with their host star. In this work, our goal is to characterize
the tidal response of a rotating hot Jupiter to the tidal semidiurnal thermal
forcing of its host star, by identifying the structure of tidal waves
responsible for variation of mass distribution, their dependence on the tidal
frequency and their ability to generate strong zonal flows. We develop an ab
initio global modeling that generalizes the early approach of Arras & Socrates
(2010) to rotating and non-adiabatic planets. We derive analytically the torque
exerted on the body and the associated timescales of evolution, as well as the
equilibrium tidal response of the atmosphere in the zero-frequency limit.
Finally, we integrate numerically the equations of thermal tides for three
cases including dissipation and rotation step by step. The resonances
associated with tidally generated gravito-inertial waves amplify significantly
the resulting tidal torque in the range 1-30 days. This torque can drive
globally the atmosphere into asynchronous rotation, as its sign depends on the
tidal frequency. The resonant behaviour of the tidal response is enhanced by
rotation, which couples the forcing to several Hough modes in the general case,
while the radiative cooling tends to regularize it and diminish its amplitude.",1801.07519v1
2021-12-19,Multi-photon multi-quantum transitions in the spin-3/2 silicon-vacancy centers of SiC,"Silicon vacancy centers in silicon carbide are promising candidates for
storing and manipulating quantum information. Implementation of fast quantum
gates is an essential requirement for quantum information processing. In a low
magnetic field, the resonance frequencies of silicon vacancy spins are in the
range of a few MHz, the same order of magnitude as the Rabi frequencies of
typical control fields. As a consequence, the rotating wave approximation
becomes invalid and nonlinear processes like the absorption and emission of
multiple photons become relevant. This work focuses on multi-photon transitions
of negatively charged silicon vacancies driven by a strong RF field. We present
continuous-wave optically detected magnetic resonance (ODMR) spectra measured
at different RF powers to identify the 1-, 2-, and 3-RF photon transitions of
different types of the silicon vacancy in the 6$H$-SIC polytype. Time-resolved
experiments of Rabi oscillations and free induction decays of these multiple RF
photon transitions were observed for the first time. Apart from zero-field
data, we also present spectra in magnetic fields with different strength and
orientation with respect to the system's symmetry axis.",2112.10211v1
2012-12-21,Momentum-dependent charge correlations in YBa$_2$Cu$_3$O$_{6+δ}$ superconductors probed by resonant x-ray scattering: Evidence for three competing phases,"We have used resonant x-ray scattering to determine the momentum dependent
charge correlations in YBa$_2$Cu$_3$O$_{6.55}$ samples with highly ordered
chain arrays of oxygen acceptors (ortho-II structure). The results reveal
nearly critical, biaxial charge density wave (CDW) correlations at in-plane
wave vectors (0.315, 0) and (0, 0.325). The corresponding scattering intensity
exhibits a strong uniaxial anisotropy. The CDW amplitude and correlation length
are enhanced as superconductivity is weakened by an external magnetic field.
Analogous experiments were carried out on a YBa$_2$Cu$_3$O$_{6.6}$ crystal with
a dilute concentration of spinless (Zn) impurities, which had earlier been
shown to nucleate incommensurate magnetic order. Compared to pristine crystals
with the same doping level, the CDW amplitude and correlation length were found
to be strongly reduced. These results indicate a three-phase competition
between spin-modulated, charge-modulated, and superconducting states in
underdoped YBa$_2$Cu$_3$O$_{6+\delta}$.",1212.5580v3
2020-08-03,High rate of gravitational waves mergers from flyby perturbations of wide black-hole triples in the field,"Ultra-wide triple black-holes (TBHs; with an outer orbit $>10^3$ AU) in the
field can be considerably perturbed by flyby encounters with field stars by the
excitation of the outer orbit eccentricities. We study the cumulative effect of
such flybys, and show them to be conductive for the production of
gravitational-wave (GW) sources. Flyby encounters with TBHs can turn the TBHs
unstable and follow chaotic evolution. This leads to a binary-single resonant
encounter between the outer BH and the inner-binary. These encounters can
result in either a prompt GW-merger of two of the TBH components during the
resonant phase, or the disruption of the TBH. In the latter case a more compact
binary is left behind, while the third BH escapes and is ejected. The compact
remnant binary may still inspiral through GW-emission, although on longer
timescales. A significant number of these would lead to a delayed GW-merger in
less than a Hubble time. We find a volumetric merger rate of $\sim3-10{\rm
Gpc^{-3}yr^{-1}}$ contributed by the (former) prompt-merger TBH channel and
$\sim100-250{\rm {\rm Gpc^{-3}yr^{-1}}}$ contributed by the (latter)
delayed-merger TBH channel. The prompt channel gives rise to eccentric mergers
in the aLIGO band, while the majority of the delayed-GW mergers are
circularized when enter the aLIGO band. We find the total {\rm eccentric}
volumetric merger rate to be $\sim1-10{\rm Gpc^{-3}yr^{-1}}$ from both
channels. We expect these mergers to show no significant spin-orbit alignment,
and uniform delay time distribution.",2008.01094v1
2020-03-12,Ensemble qubit controllability with a single control via adiabatic and rotating wave approximations,"In the physics literature it is common to see the rotating wave approximation
andthe adiabatic approximation used ""in cascade"" to justify the use of chirped
pulses for two-level quantum systems driven by one external field, in
particular when the resonance frequency of the system is not known precisely.
Both approximations need relatively long time and are essentially based on
averaging theory of dynamical systems. Unfortunately, the two approximations
cannot be done independently since, in a sense, the two time scales interact.
The purpose of this paper is to study how the cascade of the two approximations
can be justified and how large becomes the final time as the fidelity goes to
one, while preserving the robustness of the adiabatic strategy. Our first
result, based on high-order averaging techniques, gives a precise
quantification of the uncertainty interval of the resonance frequency for which
the population inversion works. As a byproduct of this result, we prove that it
is possible to control an ensemble of spin systems by a single real-valued
control, providing a non-trivial extension of a celebrated result of ensemble
controllability with two controls by Khaneja and Li.",2003.05831v2
2019-12-10,Gravitational Collider Physics,"We study the imprints of new ultralight particles on the gravitational-wave
signals emitted by binary black holes. Superradiant instabilities may create
large clouds of scalar or vector fields around rotating black holes. The
presence of a binary companion then induces transitions between different
states of the cloud, which become resonantly enhanced when the orbital
frequency matches the energy gap between the states. We find that the time
dependence of the orbit significantly impacts the cloud's dynamics during a
transition. Following an analogy with particle colliders, we introduce an
S-matrix formalism to describe the evolution through multiple resonances. We
show that the state of the cloud, as it approaches the merger, carries vital
information about its spectrum via time-dependent finite-size effects.
Moreover, due to the transfer of energy and angular momentum between the cloud
and the orbit, a dephasing of the gravitational-wave signal can occur which is
correlated with the positions of the resonances. Notably, for intermediate and
extreme mass ratio inspirals, long-lived floating orbits are possible, as well
as kicks that yield large eccentricities. Observing these effects, through the
precise reconstruction of waveforms, has the potential to unravel the internal
structure of the boson clouds, ultimately probing the masses and spins of new
particles.",1912.04932v1
2023-04-26,Short-range baryon-baryon potentials in constituent quark model revisited,"We revisit the short-range baryon-baryon potentials in the flavor SU(3)
sector, using the constituent quark model. We employ the color Coulomb, linear
confining, and color magnetic forces between two constituent quarks, and solve
the three-quark Schr\""{o}dinger equation using the Gaussian expansion method to
evaluate the wave functions of the octet $( N , \Lambda , \Sigma , \Xi )$ and
decuplet $( \Delta , \Sigma ^{\ast} , \Xi ^{\ast} , \Omega )$ baryons. We then
solve the six-quark equation using the resonating group method and
systematically calculate equivalent local potentials for the $S$-wave
two-baryon systems which reproduce the relative wave functions of two baryons
in the resonating group method. As a result, we find that the flavor
antidecuplet states with total spin $J = 3$, namely, $\Delta \Delta$, $\Delta
\Sigma ^{\ast}$, $\Delta \Xi ^{\ast}$-$\Sigma ^{\ast} \Sigma ^{\ast}$, and
$\Delta \Omega$-$\Sigma ^{\ast} \Xi ^{\ast}$ systems, have attractive
potentials sufficient to generate dibaryon bound states as hadronic molecules.
In addition, the $N \Omega$ system with $J = 2$ in coupled channels has a
strong attraction and forms a bound state. We also make a comparison with the
baryon-baryon potentials from lattice QCD simulations and try to understand the
behavior of the potentials from lattice QCD simulations.",2304.13877v2
2002-12-17,Far-infrared and submillimeter-wave conductivity in electron-doped cuprate La_{2-x}Ce_xCuO_4,"We performed far-infrared and submillimeter-wave conductivity experiments in
the electron-doped cuprate La_{2-x}Ce_xCuO_4 with x = 0.081 (underdoped regime,
T_c = 25 K). The onset of the absorption in the superconducting state is
gradual in frequency and is inconsistent with the isotropic s-wave gap.
Instead, a narrow quasiparticle peak is observed at zero frequency and a second
peak at finite frequencies, clear fingerprints of the conductivity in a d-wave
superconductor. A far-infrared conductivity peak can be attributed to 4Delta_0,
or to 2Delta_0 + Delta_spin, where Delta_spin is the resonance frequency of the
spin-fluctuations. The infrared conductivity as well as the suppression of the
quasiparticle scattering rate below T_c are qualitatively similar to the
results in the hole-doped cuprates.",0212400v1
2003-11-15,Quench dynamics across quantum critical points,"We study the quantum dynamics of a number of model systems as their coupling
constants are changed rapidly across a quantum critical point. The primary
motivation is provided by the recent experiments of Greiner et al. (Nature 415,
39 (2002)) who studied the response of a Mott insulator of ultracold atoms in
an optical lattice to a strong potential gradient. In a previous work
(cond-mat/0205169), it had been argued that the resonant response observed at a
critical potential gradient could be understood by proximity to an Ising
quantum critical point describing the onset of density wave order. Here we
obtain numerical results on the evolution of the density wave order as the
potential gradient is scanned across the quantum critical point. This is
supplemented by studies of the integrable quantum Ising spin chain in a
transverse field, where we obtain exact results for the evolution of the Ising
order correlations under a time-dependent transverse field. We also study the
evolution of transverse superfluid order in the three dimensional case. In all
cases, the order parameter is best enhanced in the vicinity of the quantum
critical point.",0311355v1
2005-06-30,Localization Transition in a Ballistic Quantum Wire,"The many-body wave-function of an interacting one-dimensional electron system
is probed, focusing on the low-density, strong interaction regime. The
properties of the wave-function are determined using tunneling between two
long, clean, parallel quantum wires in a GaAs/AlGaAs heterostructure, allowing
for gate-controlled electron density. As electron density is lowered to a
critical value the many-body state abruptly changes from an extended state with
a well-defined momentum to a localized state with a wide range of momentum
components. The signature of the localized states appears as discrete tunneling
features at resonant gate-voltages, corresponding to the depletion of single
electrons and showing Coulomb-blockade behavior. Typically 5-10 such features
appear, where the one-electron state has a single-lobed momentum distribution,
and the few-electron states have double-lobed distributions with peaks at $\pm
k_F$. A theoretical model suggests that for a small number of particles (N<6),
the observed state is a mixture of ground and thermally excited spin states.",0506812v1
2006-06-22,Impurity scattering in unconventional density waves: non-crossing approximation for arbitrary scattering rate,"We present a detailed theoretical study on the thermodynamic properties of
impure quasi-one dimensional unconventional charge-, and spin-density waves in
the framework of mean-field theory. The impurities are of the ordinary
non-magnetic type. Making use of the full self-energy that takes into account
all ladder-, and rainbow-type diagrams, we are able to calculate the relevant
low temperature quantities for arbitrary impurity concentration and scattering
rates. These are the density of states, specific heat and the shift in the
chemical potential. Our results therefore cover the whole parameter space: they
include both the self-consistent Born and the resonant unitary limits, and most
importantly give exact results in between.",0606578v2
2000-11-21,Search for Periodic Gravitational Wave Sources with the Explorer Detector,"We have developped a procedure for the search of periodic signals in the data
of gravitational wave detectors. We report here the analysis of one year of
data from the resonant detector Explorer, searching for pulsars located in the
Galactic Center (GC). No signals with amplitude greater than $\bar{h}=
2.9~10^{-24}$, in the range 921.32-921.38 Hz, were observed using data
collected over a time period of 95.7 days, for a source located at
$\alpha=17.70 \pm 0.01$ hours and $\delta=-29.00 \pm 0.05$ degrees. Our
procedure can be extended for any assumed position in the sky and for a more
general all-sky search, even with a frequency correction at the source due to
the spin-down and Doppler effects.",0011072v1
2006-04-29,Dalitz plot analysis of the decay B+- -> K+-K+-K-+,"We analyze the three-body charmless decay B+- -> K+-K+-K-+ using a sample of
226.0 +- 2.5 million BBbar pairs collected by the BABAR detector. We measure
the total branching fraction and CP asymmetry to be B = (35.2 +- 0.9 +-1.6) x
10^{-6} and A_CP = (-1.7 +- 2.6 +- 1.5)%. We fit the Dalitz plot distribution
using an isobar model and measure the magnitudes and phases of the decay
coefficients. We find no evidence of CP violation for the individual components
of the isobar model. The decay dynamics is dominated by the K+K- S-wave, for
which we perform a partial-wave analysis in the region m(K+K-) < 2 GeV/c^2.
Significant production of the f0(980) resonance, and of a spin zero state near
1.55 GeV/c^2 are required in the isobar model description of the data. The
partial-wave analysis supports this observation.",0605003v1
2004-10-05,Analysis of dephasing mechanisms in a standing wave dipole trap,"We study in detail the mechanisms causing dephasing of hyperfine coherences
of cesium atoms confined by a far off-resonant standing wave optical dipole
trap [S. Kuhr et al., Phys. Rev. Lett. 91, 213002 (2003)]. Using Ramsey
spectroscopy and spin echo techniques, we measure the reversible and
irreversible dephasing times of the ground state coherences. We present an
analytical model to interpret the experimental data and identify the
homogeneous and inhomogeneous dephasing mechanisms. Our scheme to prepare and
detect the atomic hyperfine state is applied at the level of a single atom as
well as for ensembles of up to 50 atoms.",0410037v2
2008-12-15,Collective modes and emergent SO(6) symmetry in the iron pnictides,"We show the existence of an emergent SO(6) symmetry in the low energy
description of the iron pnictides. This approximate symmetry provides a
unifying framework for the occurrence of spin density wave (SDW) and
superconductivity (SC) in these materials. We use this symmetry to make several
predictions for future experiments, including the topology of the phase diagram
and the presence of various resonant modes in neutron scattering experiments in
both the SC and SDW phases. We also predict the existence of a new ""Orbital
Density Wave"" state, which competes with both SDW and SC orders.",0812.2907v2
2010-08-18,Entanglement dynamics of two independent Jaynes-Cummings atoms without rotating-wave approximation,"Entanglement evolution of two independent Jaynes-Cummings atoms without
rotating-wave approximation (RWA) is studied by an numerically exact approach.
The previous results in the RWA are essentially modified in the strong coupling
regime ($g\ge 0.1$), which has been reached in the recent experiments on the
flux qubit coupled to the LC resonator. For the initial Bell state with
anti-correlated spins, the entanglement sudden death (ESD) is absent in the
RWA, but does appear in the present numerical calculation without RWA.
Aperiodic entanglement evolution in the strong coupling regime is observed. The
strong atom-cavity coupling facilitates the ESD. The sign of detuning play a
essential role in the entanglement evolution for strong coupling, which is
irrelevant in the RWA. An analytical results based on an unitary transformation
are also given, which could not modify the RWA picture essentially. It is
suggested that the activation of the photons may be the origin of the ESD. The
present theoretical results could be applied to artificial atoms realized in
recent experiments.",1008.3080v1
2013-05-21,"Spin fluctuations away from (pi,0) in the superconducting phase of molecular-intercalated FeSe","Magnetic fluctuations in the molecular-intercalated FeSe superconductor
Li{x}(ND2){y}(ND3){1-y}Fe2Se2 (Tc = 43K) have been measured by inelastic
neutron scattering from a powder sample. The strongest magnetic scattering is
observed at a wave vector Q ~ 1.4 A^{-1}, which is not consistent with the
(pi,0) nesting wave vector that characterizes magnetic fluctuations in several
other iron-based superconductors, but is close to the (pi, pi/2) position found
for A{x}Fe{2-y}Se2 systems. At the energies probed (~ 5kB Tc), the magnetic
scattering increases in intensity with decreasing temperature below Tc,
consistent with the superconductivity-induced magnetic resonance found in other
iron-based superconductors.",1305.4898v1
2014-03-02,A New Hypothesis On The Origin and Formation of The Solar And Extrasolar Planetary Systems,"A new theoretical hypothesis on the origin and formation of the solar and
extrasolar planetary systems is summarized and briefly discussed in the light
of recent detections of extrasolar planets, and studies of shock wave
interaction with molecular clouds, as well as H. Alfven's work on Sun's
magnetic field and its effect on the formation of the solar system (1962). We
propose that all objects in a planetary system originate from a small group of
dense fragments in a giant molecular cloud (GMC). The mechanism of one or more
shock waves, which propagate through the protoplanetary disk during the star
formation is necessary to trigger rapid cascade fragmentation of dense clumps
which in turn collapse quickly, simultaneously, and individually to form
multi-planet and multi-satellite systems. Magnetic spin resonance may be the
cause of the rotational directions of newly formed planets to couple and align
in the strong magnetic field of a younger star.",1403.0168v1
2014-09-24,Orbital symmetry of charge density wave order in La1.875Ba0.125CuO4 and YBa2Cu3O6.67,"Recent theories of charge density wave (CDW) order in high temperature
superconductors have predicted a primarily d CDW orbital symmetry. Here, we
report on the orbital symmetry of CDW order in the canonical cuprate
superconductors La1.875Ba0.125CuO4 (LBCO) and YBa2Cu3O6.67 (YBCO), using
resonant soft x-ray scattering and a model mapped to the CDW orbital symmetry.
From measurements sensitive to the O sublattice, we conclude that LBCO has
predominantly s' CDW orbital symmetry, in contrast to the d orbital symmetry
recently reported in other cuprates. Additionally, we show for YBCO that the
CDW orbital symmetry differs along the a and b crystal axes and that these both
differ from LBCO. This work highlights CDW orbital symmetry as an additional
key property that distinguishes the different cuprate families. We discuss how
the CDW symmetry may be related to the ""1/8--anomaly"" and to static spin
ordering.",1409.6787v2
2015-10-02,The Octet Meson and Octet Baryon Interaction with strangeness and the $Λ(1405)$,"The octet meson and baryon interaction with strangeness $S=-1$ is studied
fully relativistically with chiral Lagrangian. In this work, a Bethe-Salpeter
equation approach with spectator quasipotential approximation is applied to
study the reactions $K^-p\to MB$ with $MB=K^-p,\bar{K}^0n,
\pi^-\Sigma^+,\pi^0\Sigma^0, \pi^+\Sigma^-$ and $\eta \Lambda$ with all
possible partial waves and theoretical results are comparable with experimental
data. It is found that the Weinberg-Tomozawa potential derived from the lowest
order chiral Lagrangian only provides the contributions from partial waves with
spin-parities $J^P=1/2^+$ and $1/2^-$. Two-pole structure of the
$\Lambda(1405)$ is confirmed with poles at $1383+99 i$ and $1423+14i$ MeV. The
lower and higher poles originate from $\Sigma \pi$ interaction as a resonance
and $\bar{K}N$ interaction as a bound state, respectively.",1510.00580v3
2018-10-15,Collective mode in the SU(2) theory of cuprates,"Recent advances in momentum-resolved electron energy-loss spectroscopy
(MEELS) and resonant inelastic X-ray scattering (RIXS) now allow one to access
the charge response function with unprecedented versatility and accuracy. This
allows for the study of excitations which were inaccessible recently, such as
low-energy and finite momentum collective modes. The SU(2) theory of the
cuprates is based on a composite order parameter with SU(2) symmetry
fluctuating between superconductivity and charge order. The phase where it
fluctuates is a candidate for the pseudogap phase of the cuprates. This theory
has a signature, enabling its strict experimental test, which is the
fluctuation between these two orders, corresponding to a charge 2 spin 0 mode
at the charge ordering wave-vector. Here we derive the influence of this SU(2)
collective mode on the charge susceptibility in both strong and weak coupling
limits, and discuss its relation to MEELS, RIXS and Raman experiments. We find
two peaks in the charge susceptibility at finite energy, whose middle is the
charge ordering wave-vector, and discuss their evolution in the phase diagram.",1810.06485v2
2018-10-17,Conventional magnon BEC in YIG film,"The conventional magnon Bose-Einstein condensation (BEC of magnons with k =
0) is a coherent state of excited magnons described by a common wave function.
It was observed first in antiferromagnetic superfluid states of 3He. Here we
report on the discovery of a very similar magnon BEC in ferrimagnetic film at
room temperature. The experiments were performed in Yttrium Iron Garnet (YIG)
films at a magnetic field oriented perpendicular to the film. The high-density
quasiequilibrium state of excited magnon was formed by methods of pulse and/or
Continuous Waves (CW) magnetic resonance. We have observed a Long Lived
Induction Decay Signals (LLIDS), well known as a signature of spin
superfluidity. We demonstrate that the BEC state may maintain permanently by
continuous replenishment of magnons with a small radiofrequency (RF) field. Our
finding opens the way for development of potential supermagnonic applications
at an ambient conditions.",1810.08051v2
2018-12-16,Controlling light polarization by swirling surface plasmons,"Light polarization is a key aspect of modern optics. Current methods for
polarization control utilize birefringence and dichroism of anisotropic
materials or of arrays of anisotropically shaped nanostructures. Based on
collective optical effects, the resulting components remain much larger than
the wavelength of light, which limits design strategies. Here, we present a
travelling-wave plasmonic antenna that overcomes this limit using a gold-coated
helical nanowire non-radiatively fed with a dipolar aperture nanoantenna. Our
non-resonant hybrid nanoantenna enables tightly confined circularly polarized
light by swirling surface plasmons on the subwavelength scale and taking
advantage of optical spin-orbit interaction. Four closely packed circularly
polarized light sources of opposite handedness and tunable intensities are
demonstrated. By reaching near-field interaction between neighboring
nanoantennas, we obtain a highly miniaturized wave plate whose polarization
properties have never previously been demonstrated.",1812.06527v1
2020-08-15,Magnon laser based on Brillouin light scattering,"An analogous laser action of magnons would be a subject of interest and is
crucial for the study of nonlinear magnons spintronics. Here, we demonstrate
the magnon laser behavior based on Brillouin light scattering in a
ferrimagnetic insulator sphere which supports optical whispering gallery modes
and magnon resonances. We show that the excited magnon plays what has
traditionally been the role of the Stokes wave and is coherently amplified
during the Brillouin scattering process, making magnon laser possible.
Furthermore, the stimulating excited magnon number increasing exponentially
with the input light power can be manipulated by adjusting the external
magnetic field. In addition to providing insight into magneto-optical
interaction, the study of magnon laser action will help to develop novel
technologies for handling spin-wave excitations and could affect scientific
fields beyond magnonics. Potential applications range from preparing coherent
magnon sources to operating onchip functional magnetic devices.",2008.06628v2
2017-10-03,Conformer-selection by matter-wave interference,"We establish that matter-wave interference at near-resonant ultraviolet
optical gratings can be used to spatially separate individual conformers of
complex molecules. Our calculations show that the conformational purity of the
prepared beam can be close to 100% and that all molecules remain in their
electronic ground state. The proposed technique is independent of the dipole
moment and the spin of the molecule and thus paves the way for
structure-sensitive experiments with hydrocarbons and biomolecules, such as
neurotransmitters and hormones, which evaded conformer-pure isolation so far",1710.01035v2
2018-04-24,Coupling between dynamic magnetic and charge-order correlations in the cuprate superconductor Nd$_{2-x}$Ce$_{x}$CuO$_4$,"Charge order has now been observed in several cuprate high-temperature
superconductors. We report a resonant inelastic x-ray scattering experiment on
the electron-doped cuprate Nd$_{2-x}$Ce$_{x}$CuO$_4$ that demonstrates the
existence of dynamic correlations at the charge order wave vector. Upon cooling
we observe a softening in the electronic response, which has been predicted to
occur for a d-wave charge order in electron-doped cuprates. At low
temperatures, the energy range of these excitations coincides with that of the
dispersive magnetic modes known as paramagnons. Furthermore, measurements where
the polarization of the scattered photon is resolved indicate that the dynamic
response at the charge order wave vector primarily involves spin-flip
excitations. Overall, our findings indicate a coupling between dynamic magnetic
and charge-order correlations in the cuprates.",1804.09185v1
2020-10-27,Charge Density Waves and Coplanar Magnetism in Gd2PdSi3,"The intermetallic Gd2PdSi3 has recently generated a lot of excitement after
reports that it hosts chiral magnetic nano-skyrmions despite its
centrosymmetric crystal structure. Using magnetic-field-dependent polarized
resonant elastic x-ray scattering (REXS), we find than an unexpected
incommensurate charge density wave (CDW) appears below the ordering transition
with a wavevector equal to that of the magnetic textures. Furthermore, we show
these incommensurate magnetic textures in Gd2PdSi3 are highly anisotropic, with
the vast majority of the spin modulation lying within the hexagonal ab-plane.
This observation is not compatible with the previously suggested non-coplanar
magnetic textures and coplanar alternatives are discussed. Our results thus
refute the interpretation of the observed large anomalous Hall and Nernst
effects in Gd2PdSi3 as arising from topologically-nontrivial magnetic
skyrmions.",2010.14326v3
2020-12-02,"Strongly coupled charge, orbital and spin order in TbTe$_{3}$","We report a ground state with strongly coupled magnetic and charge density
wave orders mediated via orbital ordering in the layered compound \tbt. In
addition to the commensurate antiferromagnetic (AFM) and charge density wave
(CDW) orders, new magnetic peaks are observed whose propagation vector equals
the sum of the AFM and CDW propagation vectors, revealing an intricate and
highly entwined relationship. This is especially interesting given that the
magnetic and charge orders lie in different layers of the crystal structure
where the highly localized magnetic moments of the Tb$^{3+}$ ions are netted in
the Tb-Te stacks, while the charge order is formed by the conduction electrons
of the adjacent Te-Te layers. Our results, based on neutron diffraction and
resonant x-ray scattering reveal that the charge and magnetic subsystems
mutually influence each other via the orbital ordering of Tb$^{3+}$ ions.",2012.01217v1
2021-05-24,Generation of Bimodal Solitons in a Sapphire Whispering Gallery Mode Maser at Millikelvin Temperatures,"We present experimental observations of bimodal solitons in a solid state
three-level maser cooled to millikelvin temperatures. The maser is built on a
highly dilute $\textrm{Fe}^{3+}$ spin ensemble hosted by a high purity
$\textrm{Al}_{2}\textrm{O}_{3}$ crystal constituting a high quality factor
whispering-gallery-mode resonator. The maser is pumped through one of these
modes, near 31 GHz, generating two signals near 12.04 GHz from two distinct
modes, 8 MHz apart. The system demonstrates three regimes, namely, a continuous
wave regime, a dense soliton regime and a sparse soliton regime. These results
open new avenues for studying nonlinear wave phenomena using microwave systems
as well as new applications of solitons in this part of the electromagnetic
spectrum.",2105.11180v3
2021-07-15,Exciton-exciton and exciton-charge carrier interaction and the exciton collisional broadening in GaAs/AlGaAs quantum wells,"Wave functions of heavy-hole excitons in GaAs/Al$_{0.3}$Ga$_{0.7}$As square
quantum wells (QWs) of various widths are calculated by the direct numerical
solution of a three-dimensional Schr\""odinger equation using a
finite-difference scheme. These wave functions are then used to determine the
exciton-exciton, exciton-electron and exciton-hole fermion exchange constants
in a wide range of QW widths (5-150 nm). Additionally, the spin-dependent
matrix elements of elastic exciton-exciton, exciton-electron and exciton-hole
scattering are calculated. From these matrix elements, the collisional
broadening of the exciton resonance is obtained within the Born approximation
as a function of the areal density of excitons, electrons and holes
respectively for QW widths of 5, 15, 30 and 50 nm. The obtained numerical
results are compared with other theoretical works.",2107.07273v1
2022-05-17,Atomic scale visualization of the p-d hybridization in III-V semiconductors doped with transition metal impurities,"p-d hybridization of transition metal impurities in a semiconductor host is
the mechanism that couples valence-band electrons and localized spins. We use
scanning tunneling microscopy and spectroscopy combined with density functional
theory to probe at the atomic scale hybridization of Cr single impurities with
GaAs host. Combining spatial density of states mapping and in-gap states
spectroscopy of the Cr substituted at the surface of the semiconductor, we give
a detailed picture of the spatial extension and the electronic structure of the
strongly anisotropic wave function of Cr on GaAs(110). First principles
calculations allow to identify electronic character and origin of each states
and show that the main resonance peaks and the wave function with ""drop-eyes""
lobes experimentally observed for 3d metal impurities in III-V semiconductor
are direct local evidences of the p-d hybridization.",2205.08400v1
2022-11-28,Surface Acoustic Wave Cavity Optomechanics with WSe$_2$ Single Photon Emitters,"Surface acoustic waves (SAWs) are a versatile tool for coherently interfacing
with a variety of solid-state quantum systems spanning microwave to optical
frequencies, including superconducting qubits, spins, and quantum emitters.
Here, we demonstrate SAW cavity optomechanics with quantum emitters in 2D
materials, specifically monolayer WSe$_2$, on a planar lithium niobate SAW
resonator driven by superconducting electronics. Using steady-state
photoluminescence spectroscopy and time-resolved single-photon counting, we map
the temporal dynamics of modulated 2D emitters under coupling to different SAW
cavity modes, showing energy-level splitting consistent with deformation
potential coupling of 30 meV/%. We leverage the large anisotropic strain from
the SAW to modulate the excitonic fine-structure splitting on a nanosecond
timescale, which may find applications for on-demand entangled photon-pair
generation from 2D materials. Cavity optomechanics with SAWs and 2D quantum
emitters provides opportunities for compact sensors and quantum
electro-optomechanics in a multi-functional integrated platform that combines
phononic, optical, and superconducting electronic quantum systems.",2211.15811v1
2023-09-19,Optical and Raman spectroscopies of $^{171}\mathrm{Yb}^{3+}$:$\mathrm{Y}_2\mathrm{SiO}_5$ hyperfine structure for application toward microwave-to-optical transducer,"Optical techniques for precise and repeatable spectroscopy of
ytterbium-isotope-171 ion ($^{171}\mathrm{Yb}^{3+}$) hyperfine structure were
studied. Large energy spacing of $^{171}\mathrm{Yb}^{3+}$ regarded as the main
motivation for state preparations required for quantum memory and transducer
applications promoted us to develop stabilization and control of optical
frequencies of lasers simultaneously over a wide range of 3 gigahertz's. We
also built our own 2.7 kelvins cryogenic system for radio-wave assisted optical
spectroscopy. We attained to high resolution and sensitivity both in pump-probe
saturation spectroscopy and Raman heterodyne spectroscopy. The first one gave a
high resolution spectrum of hyperfine structure, and the second one enabled to
detect paramagnetic spin resonance efficiently for wide ranges of
radio-frequency. As the Raman heterodyne process of our interest is the
up-conversion of transductions, we made efforts at optimizing sensitivity of
Raman heterodyne detections with selecting the best crystal orientation and
with efficient radio-wave coupling for future applications toward photon
transducer.",2309.10277v1
1996-03-26,Spin Diffusion in 2D XY Ferromagnet with Dipolar Interaction,"In the ordered phase of 2D XY ferromagnet the dipolar interaction between
spins induces a strong, relevant interaction between spin-waves. We study
quasi-excitations of the interacting spin-wave 'liquid' in the long wavelength
limit. We employ the Janssen-De-Dominicis method for classical Langevin
equation to find the transformation of the spin-wave excitation into a new
soft-mode excitation in the intermediate range of wavelengths; and into an
anomalous anisotropic diffusion mode excitation at long wavelengths. The
dissipation of a spin-wave at short wavelengths is found to be highly
anisotropic.",9603160v1
1999-09-17,Finite size Spin Wave theory of the triangular Heisenberg model,"We present a finite size spin wave calculation on the Heisenberg
antiferromagnet on the triangular lattice focusing in particular on the
low-energy part of the excitation spectrum. For s=1/2 the good agreement with
the exact diagonalization and quantum Monte Carlo results supports the
reliability of the spin wave expansion to describe the low-energy spin
excitations of the Heisenberg model even in presence of frustration. This
indicates that the spin susceptibility of the triangular antiferromagnet is
very close to the linear spin wave result.",9909268v1
2002-04-03,Spin Waves in Disordered III-V Diluted Magnetic Semiconductors,"We propose a new scheme for numerically computing collective-mode spectra for
large-size systems, using a reformulation of the Random Phase Approximation. In
this study, we apply this method to investigate the spectrum and nature of the
spin-waves of a (III,Mn)V Diluted Magnetic Semiconductor. We use an impurity
band picture to describe the interaction of the charge carriers with the local
Mn spins. The spin-wave spectrum is shown to depend sensitively on the
positional disorder of the Mn atoms inside the host semiconductor. Both
localized and extended spin-wave modes are found. Unusual spin and charge
transport is implied.",0204092v1
2005-01-27,Current-induced macrospin vs spin-wave excitations in spin valves,"The mode dependence of current-induced magnetic excitations in spin valves is
studied theoretically. The torque exerted on the magnetization by transverse
spin currents as well as the Gilbert damping constant are found to depend
strongly on the wave length of the excitation (spin wave). Analytic expressions
are presented for the critical currents that excite a selected spin wave. The
onset of macrospin (zero wavelength) vs finite wavelength instabilities depends
on the device parameters and the current direction, in agreement with recent
experimental findings.",0501672v3
2013-03-20,Spin-pumping and Enhanced Gilbert Damping in Thin Magnetic Insulator Films,"Precessing magnetization in a thin film magnetic insulator pumps spins into
adjacent metals; however, this phenomenon is not quantitatively understood. We
present a theory for the dependence of spin-pumping on the transverse mode
number and in-plane wave vector. For long-wavelength spin waves, the enhanced
Gilbert damping for the transverse mode volume waves is twice that of the
macrospin mode, and for surface modes, the enhancement can be ten or more times
stronger. Spin-pumping is negligible for short-wavelength exchange spin waves.
We corroborate our analytical theory with numerical calculations in agreement
with recent experimental results.",1303.4922v1
2013-07-11,Direct evidence of nuclear spin waves in Nd$_2$CuO$_4$ by high-resolution neutron-spin-echo spectroscopy,"We investigated the dispersion of nuclear spin waves in Nd$_2$CuO$_4$ by
using neutron spin-echo spectroscopy at millikelvin temperatures. Our results
show unambiguously the existence of dispersion of nuclear spin waves in
Nd$_2$CuO$_4$ at T = 30 mK. A fit of the dispersion data with the spin wave
dispersion formula gave the Suhl-Nakamura interaction range to be of the order
of 10 {\AA}.",1307.2998v1
2021-11-24,Spin Hall response at finite wave vector in ferromagnets,"Spin Hall effect at finite wave vector in a ferromagnetic conductor is
theoretically studied by calculating the spin density as the linear response to
an applied electric field. The cases of a spin-orbit interaction due to random
impurities and a localized Rashba interaction are considered. It is shown that
the spin Hall effect has a broad response for the wave vector $q\lesssim 2\kf$
where $\kf $ is the Fermi wave vector. This fact confirms the local nature of
the spin-charge conversion effects.",2111.12247v1
2004-10-07,Resonant spin Hall conductance in quantum Hall systems lacking bulk and structural inversion symmetry,"Following a previous work [Shen, Ma, Xie and Zhang, Phys. Rev. Lett. 92,
256603 (2004)] on the resonant spin Hall effect, we present detailed
calculations of the spin Hall conductance in two-dimensional quantum wells in a
strong perpendicular magnetic field. The Rashba coupling, generated by
spin-orbit interaction in wells lacking bulk inversion symmetry, introduces a
degeneracy of Zeeman-split Landau levels at certain magnetic fields. This
degeneracy, if occuring at the Fermi energy, will induce a resonance in the
spin Hall conductance below a characteristic temperature of order of the Zeeman
energy. At very low temperatures, the spin Hall current is highly non-ohmic.
The Dresselhaus coupling due to the lack of structure inversion symmetry
partially or completely suppresses the spin Hall resonance. The condition for
the resonant spin Hall conductance in the presence of both Rashba and
Dresselhaus couplings is derived using a perturbation method. In the presence
of disorder, we argue that the resonant spin Hall conductance occurs when the
two Zeeman split extended states near the Fermi level becomes degenerate due to
the Rashba coupling and that the the quantized charge Hall conductance changes
by 2e^2/h instead of e^2/h as the magnetic field changes through the resonant
field.",0410169v1
2022-05-17,Spin dynamics of positively charged excitons in Cr$^+$-doped quantum dots probed by resonant photoluminescence,"We study the dynamics of the spin system that consist of a positively charged
II-VI semiconductor quantum dot doped with a single Cr$^+$ ion. The resonant
photoluminescence (PL) of the positively charged exciton coupled with the
Cr$^+$ spin is used to analyze the main spin relaxation channels. The intensity
of the resonant PL is reduced by an optical pumping of the spin of the resident
hole-Cr$^+$ complex that can be seen as a nano-magnet. The spin memory can be
partially erased by a non-resonant optical excitation. This leads to an
increase of the resonant PL signal. The resonant PL is co-circularly polarized
and corresponds to relaxation channels that conserve the Cr$^+$ spin $\vert S_z
\vert$. The observation in the resonant-PL excitation spectra of optical
transitions with a change of the Cr$^+$ spin permits to determine the magnetic
anisotropy of the magnetic atom. Optical pumping, auto-correlation measurements
and the power dependence of the PL intensity distribution show that the
effective temperature of the hole-Cr$^+$ spin system is affected by the optical
excitation through the local generation of phonons.",2205.08122v1
2018-10-23,Skyrme functional with tensor terms from \textit{ab initio} calculations of neutron-proton drops,"A new Skyrme functional devised to account well for standard nuclear
properties as well as for spin and spin-isospin properties is presented. The
main novelty of this work relies on the introduction of tensor terms guided by
\textit{ab initio} relativistic Brueckner-Hartree-Fock calculations of
neutron-proton drops. The inclusion of tensor term does not decrease the
accuracy in describing bulk properties of nuclei, experimental data of some
selected spherical nuclei such as binding energies, charge radii, and
spin-orbit splittings can be well fitted. The new functional is applied to the
investigation of various collective excitations such as the Giant Monopole
Resonance (GMR), the Isovector Giant Dipole Resonance (IVGDR), the Gamow-Teller
Resonance (GTR), and the Spin-Dipole Resonance (SDR). The overall description
with the new functional is satisfactory and the tensor terms are shown to be
important particularly for the improvement of the Spin-Dipole Resonance
results. Predictions for the neutron skin thickness based on the non-energy
weighted sum rule of the Spin-Dipole Resonance are also given.",1810.09691v2
1995-12-18,Raman scattering in a two-layer antiferromagnet,"Two--magnon Raman scattering is a useful tool to verify recent suggestions
concerning the value of the interplanar exchange constant in antiferromagnetic
two--layer systems, such as $YBa_2Cu_3O_{6+x}$. We present a theory for Raman
scattering in a two--layer antiferromagnet. We study the spectra for the
electronic and magnetic excitations across the charge transfer gap within the
one--band Hubbard model and derive the matrix elements for the Raman scattering
cross section in a diagrammatic formalism. We analyze the effect of the
interlayer exchange coupling $J_2$ for the Raman spectra in $A_{1g}$ and
$B_{1g}$ scattering geometries both in the non--resonant regime (when the
Loudon--Fleury model is valid), and at resonance. We show that within the
Loudon--Fleury approximation, a nonzero $J_2$ gives rise to a finite signal in
$A_{1g}$ scattering geometry. Both, in this approximation and at resonance, the
intensity in the $A_{1g}$ channel has a peak at {\it small} transferred
frequency equal to twice the gap in the spin--wave spectrum. We compare our
results with experiments in $YBa_2Cu_3O_{6.1}$ and $Sr_2CuO_2Cl_2$ compounds
and argue that the large value of $J_2$ suggested in a number of recent studies
is incompatible with Raman experiments in $A_{1g}$ geometry.",9512131v1
2009-05-01,Vortex core states in a minimal two-band model for iron-based superconductors,"The pairing symmetry is one of the major issues in the study of iron-based
superconductors. We adopt a minimal two-band tight-binding model with various
channels of pairing interaction, and derive a set of two-band Bogoliubov-de
Gennes (BdG) equations. The BdG equations are implemented in real space and
then solved self-consistently via exact diagonalization. In the uniform case,
we find that the $d_{x^2-y^2}$-wave pairing state is most favorable for a
nearest-neighbor pairing interaction while the $s_{x^2y^2}$-wave pairing state
is most favorable for a next-nearest-neighbor pairing interaction. The is
consistent with that reported by Seo {\em et al.} [Phys. Rev. Lett. {\bf 101},
206404 (2008)]. We then proceed to study the local electronic structure around
a magnetic vortex core for both $d_{x^2-y^2}$-wave and $s_{x^2y^2}$-wave
pairing symmetry in the mixed state. It is found from the local density of
states (LDOS) spectra and its spatial variation that the resonance core states
near the Fermi energy for the $d_{x^2-y^2}$-wave pairing symmetry are bound
while those for the $s_{x^2y^2}$-wave pairing symmetry can evolve from the
localized states into extended ones with varying electron filling factor.
Furthermore, by including an effective exchange interaction, the emergent
antiferromagnetic spin-density-wave (SDW) order can suppress the resonance core
states, which provides one possible avenue to understand the absence of
resonance peak as revealed by recent scanning tunneling microscopy experiment
(STM) by Yin {\em et al.} [Phys. Rev. Lett. {\bf 102}, 097002 (2009)].",0905.0014v2
2010-05-18,Micromagnetic simulations of spinel ferrite particles,"This paper presents the results of simulations of the magnetization field
{\it ac} response (at $2$ to $12$ GHz) of various submicron ferrite particles
(cylindrical dots). The ferrites in the present simulations have the spinel
structure, expressed here by M$_{1-n}$Zn$_{n}$Fe$_2$O$_4$ (where M stands for a
divalent metal), and the parameters chosen were the following: (a) for $n=0$: M
= \{ Fe, Mn, Co, Ni, Mg, Cu \}; (b) for $n=0.1$: M = \{ Fe, Mg \} (mixed
ferrites). These runs represent full 3D micromagnetic (one-particle) ferrite
simulations. We find evidences of confined spin waves in all simulations, as
well as a complex behavior nearby the main resonance peak in the case of the M
= \{ Mg, Cu \} ferrites. A comparison of the $n=0$ and $n=0.1$ cases for fixed
M reveals a significant change in the spectra in M = Mg ferrites, but only a
minor change in the M = Fe case. An additional larger scale simulation of a $3$
by $3$ particle array was performed using similar conditions of the Fe$_3$O$_4$
(magnetite; $n=0$, M = Fe) one-particle simulation. We find that the main
resonance peak of the Fe$_3$O$_4$ one-particle simulation is disfigured in the
corresponding 3 by 3 particle simulation, indicating the extent to which
dipolar interactions are able to affect the main resonance peak in that
magnetic compound.",1005.3169v1
2011-02-04,Ultracold $O_2$+$O_2$ collisions in a magnetic field: on the role of the potential energy surface,"The collision dynamics of $^{17}O_2(^3\Sigma_g^-) +^{17}O_2(^3\Sigma_g^-)$ in
the presence of a magnetic field is studied within the close-coupling formalism
in the range between 10 nK and 50 mK. A recent global {\em ab initio} potential
energy surface (PES) is employed and its effect on the dynamics is analyzed and
compared with previous calculations where an experimentally derived PES was
used [New J. Phys {\bf 11}, 055021 (2009)]. In contrast to the results using
the older PES, magnetic field dependence of the low-field-seeking state in the
ultracold regime is characterized by quite a large background scattering
length, $a_{bg}$, and, in addition, cross sections exhibit broad and pronounced
Feshbach resonances. The marked resonance structure is somewhat surprising
considering the influence of inelastic scattering, but it can be explained by
resorting to the analytical van der Waals theory, where the short range
amplitude of the entrance channel wave function is enhanced by the large
$a_{bg}$. This strong sensitivity to the short range of the {\em ab initio} PES
persists up to relatively high energies (10 mK). After this study and despite
quantitative predictions are very difficult, it can be concluded that the ratio
between elastic and spin relaxation scattering is generally small, except for
magnetic fields which are either low or close to an asymmetric Fano-type
resonance. Some general trends found here, such as a large density of
quasibound states and a propensity towards large scattering lengths, could be
also characteristic of other anisotropic molecule-molecule systems.",1102.0883v1
2013-11-29,Magnon radiation by moving Abrikosov vortices in ferromagnetic superconductors and superconductor-ferromagnet multilayers,"In systems combining type-II superconductivity and magnetism the
non-stationary magnetic field of moving Abrikosov vortices may excite spin
waves, or magnons. This effect leads to the appearance of an additional damping
force acting on the vortices. By solving the London and Landau-Lifshitz-Gilbert
equations we calculate the magnetic moment induced force acting on vortices in
ferromagnetic superconductors and superconductor/ferromagnet superlattices. If
the vortices are driven by a dc force, magnon generation due to the Cherenkov
resonance starts as the vortex velocity exceeds some threshold value. For an
ideal vortex lattice this leads to an anisotropic contribution to the
resistivity and to the appearance of resonance peaks on the current voltage
characteristics. For a disordered vortex array the current will exhibit a
step-like increase at some critical voltage. If the vortices are driven by an
ac force with a frequency \omega, the interaction with magnetic moments will
lead to a frequency-dependent magnetic contribution \eta_M to the vortex
viscosity. If \omega is below the ferromagnetic resonance frequency \omega_F,
vortices acquire additional inertia. For \omega > \omega_F dissipation is
enhanced due to magnon generation. The viscosity \eta_M can be extracted from
the surface impedance of the ferromagnetic superconductor. Estimates of the
magnetic force acting on vortices for the U-based ferromagnetic superconductors
and cuprate/manganite superlattices are given.",1311.7620v1
2015-10-23,Meson Spectroscopy at COMPASS,"The COmmon Muon and Proton Apparatus for Structure and Spectroscopy (COMPASS)
is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron
(SPS) aimed at studying the structure and spectrum of hadrons. The two-stage
spectrometer has a good acceptance for charged as well as neutral particles
over a wide kinematic range and thus allows to access a wide range of
reactions. Light mesons are studied with negative (mostly $\pi^-$) and positive
($p$, $\pi^+$) hadron beams with a momentum of 190 GeV/$c$. The spectrum of
light mesons is investigated in various final states produced in diffractive
dissociation reactions at squared four-momentum transfers to the target between
0.1 and 1.0 $(\text{GeV}/c)^2$. The flagship channel is the $\pi^-\pi^+\pi^-$
final state, for which COMPASS has recorded the currently largest data sample.
These data not only allow to measure the properties of known resonances with
high precision, but also to search for new states. Among these is a new
resonance-like signal, the $a_1(1420)$, with unusual properties. Of particular
interest is also the resonance content of the partial wave with spin-exotic
$J^{PC} = 1^{-+}$ quantum numbers, which are forbidden for quark-antiquark
states.",1510.07032v2
2018-03-28,Photon echo from localized excitons in semiconductor nanostructures,"An overview on photon echo spectroscopy under resonant excitation of the
exciton complexes in semiconductor nanostructures is presented. The use of
four-wave-mixing technique with the pulsed excitation and heterodyne detection
allowed us to measure the coherent response of the system with the picosecond
time resolution. It is shown that, for resonant selective pulsed excitation of
the localized exciton complexes, the coherent signal is represented by the
photon echoes due to the inhomogeneous broadening of the optical transitions.
In case of resonant excitation of the trions or donor-bound excitons, the
Zeeman splitting of the resident electron ground state levels under the applied
transverse magnetic field results in quantum beats of photon echo amplitude at
the Larmor precession frequency. Application of magnetic field makes it
possible to transfer coherently the optical excitation into the spin ensemble
of the resident electrons and to observe a long-lived photon echo signal. The
described technique can be used as a high-resolution spectroscopy of the energy
splittings in the ground state of the system. Next, we consider the Rabi
oscillations and their damping under excitation with intensive optical pulses
for the excitons complexes with a different degree of localization. It is shown
that damping of the echo signal with increase of the excitation pulse intensity
is strongly manifested for excitons, while on trions and donor-bound excitons
this effect is substantially weaker.",1803.10651v4
2018-06-11,Excitation of whispering gallery magnons in a magnetic vortex,"One of the most fascinating topics in current quantum physics are hybridised
systems, in which different quantum resonators are strongly coupled. Prominent
examples are circular resonators with high quality factors that allow the
coupling of optical whispering gallery modes to microwave cavities or magnon
resonances in optomagnonics. Whispering gallery modes play a special role in
this endeavour because of their high quality factor and strong localisation,
which ultimately increases the overlap of the wavefunctions of quantum
particles in hybridised systems. The hybridisation with magnons, the collective
quantum excitations of the electron spins in a magnetically ordered material,
is of particular interest because magnons can take over two functionalities:
due to their collective nature they are robust and can serve as a quantum
memory and, moreover, they can act as a wavelength converter between microwave
and THz photons. However, the observation of whispering gallery magnons has not
yet been achieved due to the lack of efficient excitation schemes for magnons
with large wave vectors in a circular geometry. To tackle this problem, we
studied nonlinear 3-magnon scattering as a means to generate whispering gallery
magnons. This Letter discusses the basics of this nonlinear mechanism in a
confined, circular geometry from experimental and theoretical point of view.",1806.03910v1
2018-09-11,Detecting Crystallographic Lattice Chirality using Resonant Inelastic X-ray Scattering,"The control and detection of crystallographic chirality is an important and
challenging scientific problem. Chirality has wide ranging implications from
medical physics to cosmology including an intimate but subtle connection in
magnetic systems, for example Mn$_{1-x}$Fe$_{x}$Si. X-ray diffraction
techniques with resonant or polarized variations of the experimental setup are
currently utilized to characterize lattice chirality. We demonstrate using
theoretical calculations the feasibility of indirect $K$ -edge bimagnon
resonant inelastic X-ray scattering (RIXS) spectrum as a viable experimental
technique to distinguish crystallographic handedness. We apply spin wave theory
to the recently discovered $\sqrt {5}\times\sqrt {5}$ vacancy ordered
chalcogenide Rb$_{0.89}$Fe$_{1.58}$Se$_{2}$ for realistic X-ray experimental
set up parameters (incoming energy, polarization, and Bragg angle) to show that
the computed RIXS spectrum is sensitive to the underlying handedness (right or
left) of the lattice. A Flack parameter definition that incorporates the right-
and left- chiral lattice RIXS response is introduced. It is shown that the RIXS
response of the multiband magnon system RbFeSe arises both from inter- and
intra- band scattering processes. The extinction or survival of these RIXS
peaks are sensitive to the underlying chiral lattice orientation. This in turn
allows for the identification of the two chiral lattice orientations.",1809.04148v2
2019-03-02,Microwave excitations and hysteretic magnetization dynamics of stripe domain films,"FeNi films with the stripe domain (SD) pattern are prepared by
electrodeposition and sputtering methods. The magnetic domain, static magnetic
parameters, and quality factor, as well as dynamic properties of the two films,
are respectively performed. The results show the magnetizations of the film
were dependent on the direction of SD, and the rotation of the SD is lagging
behind the magnetization reversal. The microwave properties of the SD emerge
dynamic hysteresis before the saturation magnetic field. These microwave
properties are selectively excited with acoustic mode, optical mode, and
spin-wave mode. The frequency and intensity of different resonance modes of
stripe domain are determined by the local magnetization. The magnetization
variations and the rotation of SD of different modes are further illuminated by
the micromagnetic simulation. The magnetic anisotropy and the resonance
intensity of permeability of different modes were finally described by the
modified resonance equations.",1903.00656v2
2008-06-26,Ferromagnetic resonance force spectroscopy of individual sub-micron size samples,"We review how a magnetic resonance force microscope (MRFM) can be applied to
perform ferromagnetic resonance (FMR) spectroscopy of \emph{individual}
sub-micron size samples. We restrict our attention to a thorough study of the
spin-wave eigen-modes excited in permalloy (Py) disks patterned out of the same
43.3 nm thin film. The disks have a diameter of either 1.0 or $0.5 \mu$m and
are quasi-saturated by a perpendicularly applied magnetic field. It is shown
that \emph{quantitative} spectroscopic information can be extracted from the
MRFM measurements. In particular, the data are extensively compared with
complementary approximate models of the dynamical susceptibility: i) a 2D
analytical model, which assumes an homogeneous magnetization dynamics along the
thickness and ii) a full 3D micromagnetic simulation, which assumes an
homogeneous magnetization dynamics below a characteristic length scale $c$ and
which approximates the cylindrical sample volume by a discretized
representation with regular cubic mesh of lateral size $c=3.9$ nm. In our
analysis, the distortions due to a breaking of the axial symmetry are taken
into account, both models incorporating the possibility of a small misalignment
between the applied field and the normal of the disks.",0806.4244v1
2019-01-21,Resonant inelastic x-ray incarnation of Young's double-slit experiment,"Young's archetypal double-slit experiment forms the basis for modern
diffraction techniques: the elastic scattering of waves yields an interference
pattern that captures the real-space structure. Here, we report on an inelastic
incarnation of Young's experiment and demonstrate that resonant inelastic x-ray
scattering (RIXS) measures interference patterns which reveal the symmetry and
character of electronic excited states in the same way as elastic scattering
does for the ground state. A prototypical example is provided by the
quasi-molecular electronic structure of insulating Ba3CeIr2O9 with structural
Ir dimers and strong spin-orbit coupling. The double 'slits' in this resonant
experiment are the highly localized core levels of the two Ir atoms within a
dimer. The clear double-slit-type sinusoidal interference patterns that we
observe allow us to characterize the electronic excitations, demonstrating the
power of RIXS interferometry to unravel the electronic structure of solids
containing, e.g., dimers, trimers, ladders, or other superstructures.",1901.07027v1
2020-05-29,Photo-Induced Anomalous Hall Effect in Two-Dimensional Transition-Metal Dichalcogenides,"A circularly polarized a.c. pump field illuminated near resonance on
two-dimensional transition metal dichalcogenides (TMDs) produces an anomalous
Hall effect in response to a d.c. bias field. In this work, we develop a theory
for this photo-induced anomalous Hall effect in undoped TMDs irradiated by a
strong coherent laser field. The strong field renormalizes the equilibrium
bands and opens up a dynamical energy gap where single-photon resonance occurs.
The resulting photon dressed states, or Floquet states, are treated within the
rotating wave approximation. A quantum kinetic equation approach is developed
to study the non-equilibrium density matrix and time-averaged transport
currents under the simultaneous influence of the strong a.c. pump field and the
weak d.c. probe field. Dissipative effects are taken into account in the
kinetic equation that captures relaxation and dephasing. The photo-induced
longitudinal and Hall conductivities display notable resonant signatures when
the pump field frequency reaches the spin-split interband transition energies.
Rather than valley polarization, we find that the anomalous Hall current is
mainly driven by the intraband response of photon-dressed electron populations
near the dynamical gap at both valleys, accompanied by a smaller contribution
due to interband coherences. These findings highlight the importance of
photon-dressed bands and non-equilibrium distribution functions in achieving a
proper understanding of photo-induced anomalous Hall effect in a strong pump
field.",2006.00081v1
2022-05-19,Resonant phonon-magnon interactions in free-standing metal-ferromagnet multilayer structures,"We analyze resonant magneto-elastic interactions between standing
perpendicular spin wave modes (exchange magnons) and longitudinal acoustic
phonon modes in free-standing hybrid metal-ferromagnet bilayer and trilayer
structures. Whereas the ferromagnetic layer acts as a magnetic cavity, all
metal layers control the frequencies and eigenmodes of acoustic vibrations. The
here proposed design allows for achieving and tuning the spectral and spatial
modes overlap between phonons and magnons that results in their strong resonant
interaction. Realistic simulations for gold-nickel multilayers show that
sweeping the external magnetic field should allow for observing resonantly
enhanced interactions between individual magnon and phonon modes in a broad
range of frequencies spanning from tens of GHz up to several hundreds of GHz,
which can be finely tuned through the multilayer design. Our results would
enable the systematic study and the deep understanding of resonantly enhanced
magneto-elastic coupling between individual phonon and magnon modes up to
frequencies of great contemporary fundamental and applied interest.",2205.09805v1
2022-06-30,Evidence for ground state coherence in a two-dimensional Kondo lattice,"Kondo lattices are ideal testbeds for the exploration of heavy-fermion
quantum phases of matter. While our understanding of Kondo lattices has
traditionally relied on complex bulk f-electron systems, transition metal
dichalcogenide heterobilayers have recently emerged as simple, accessible and
tunable 2D Kondo lattice platforms where, however, their ground state remains
to be established. Here we present evidence of a coherent ground state in the
1T/1H-TaSe2 heterobilayer by means of scanning tunneling
microscopy/spectroscopy at 340 mK. Our measurements reveal the existence of two
symmetric electronic resonances around the Fermi energy, a hallmark of
coherence in the spin lattice. Spectroscopic imaging locates both resonances at
the central Ta atom of the charge density wave of the 1T phase, where the
localized magnetic moment is held. Furthermore, the evolution of the electronic
structure with the magnetic field reveals a non-linear increase of the energy
separation between the electronic resonances. Aided by ab initio and
auxiliary-fermion mean-field calculations, we demonstrate that this behavior is
inconsistent with a fully screened Kondo lattice, and suggests a ground state
with magnetic order mediated by conduction electrons. The manifestation of
magnetic coherence in TMD-based 2D Kondo lattices enables the exploration of
magnetic quantum criticality, Kondo breakdown transitions and unconventional
superconductivity in the strict two-dimensional limit.",2207.00096v3
2023-01-22,Scattering-matrix approach for a quantitative evaluation of the topological protection in valley photonic crystals,"In this work, we use valley-topological triangular resonators coupled to an
input waveguide to evaluate the quality of the topological protection. To that
purpose, we first analyze via numerical simulations the existence of backward
scattering at cavity corners or transmission with pseudo-spin conversion at the
splitter between the input waveguide and the cavity. We evidence that a
breakdown of topological protection takes place, in particular at sharp
corners, which results in transmission minima and split-resonances, otherwise
non-existent. In order to evaluate the small coupling coefficients associated
to this breakdown, a phenomenological model based on an exact parameterization
of scattering matrices at splitters and corners of the resonators is then
introduced. By comparison with the numerical simulations, we are able to
quantify the loss of topological protection at sharp bends and splitters.
Finally, we use the obtained set of phenomenological parameters to compare the
predictions of the phenomenological model with full numerical simulations for
fractal-inspired cavities based on the Sierpi\'nski triangle construction. We
show that the agreement is overall good, but shows more differences for the
cavity composed of the smallest triangles. Our results suggest that even in a
system exempt of geometrical and structural defects, topological protection is
not complete at corners, sharp bends and splitters. However, simpler but
predictive calculations can be realized with a phenomenological approach,
allowing simulations of very large devices beyond the reach of standard
simulation methods, which is crucial to design photonic devices which gather
compactness and low losses through topological conduction of electromagnetic
waves.",2301.10565v2
2023-08-07,Bespoke Dual Resonance,"Dual resonance is one of the great miracles of string theory. At a
fundamental level, it implies that the particles exchanged in different
channels are subtly equivalent. Furthermore, it is inextricably linked to the
property of exceptionally tame high-energy behavior. In this paper, we present
explicit, closed-form expressions for a new class of dual resonant amplitudes
describing an infinite tower of spins for an arbitrary mass spectrum. In
particular, the input of our construction is a user-defined, fully customizable
choice of masses. The resulting ""bespoke"" amplitudes are well behaved in the
ultraviolet and analytic except at simple poles whose residues are polynomial
in the momentum transfer, in accordance with locality. The absence of branch
cuts can be seen using Newton's identities, but can also be made manifest by
expressing the amplitudes as a simple dlog integral of the Veneziano amplitude
that remaps the linear Regge trajectories of the string to a tunable spectrum.
We identify open regions of parameter space that firmly deviate from string
theory but nevertheless comport with partial wave unitarity. Last but not
least, we generalize our construction to the scattering of any number of
particles in terms of a dlog transform of the Koba-Nielsen worldsheet integral
formula.",2308.03833v2
2023-11-17,"The $\mathbf{\bar{q}q\bar{s}Q}$ $\mathbf{(q=u,\,d;\,Q=c,\,b)}$ tetraquark system in a chiral quark model","Inspired by the experimentally reported $T_{c\bar{s}}(2900)$ exotic states,
the $S$-wave $\bar{q}q\bar{s}Q$ $(q=u,\,d;\,Q=c,\,b)$ tetraquarks, with
spin-parity $J^P=0^+$, $1^+$ and $2^+$, in both isoscalar and isovector sectors
are systematically studied in a chiral quark model. The meson-meson,
diquark-antidiquark and K-type arrangements of quarks, along with all possible
color wave functions, are comprehensively considered. The four-body system is
solved by means of a highly efficient computational approach, the Gaussian
expansion method, along with a complex-scaling formulation of the problem to
disentangle bound, resonance and scattering states. This theoretical framework
has already been successfully applied in various tetra- and penta-quark
systems. In the complete coupled-channel case, and within the complex-range
formulation, several narrow resonances of $\bar{q}q\bar{s}c$ and
$\bar{q}q\bar{s}b$ systems are obtained in each allowed $I(J^P)$-channels.
Particularly, the $T_{c\bar{s}}(2900)$ is well identified as a $I(J^P)=1(0^+)$
$\bar{q}q\bar{s}c$ tetraquark state with a dominant molecular structure.
Meanwhile, more resonances in $\bar{q}q\bar{s}c$ and $\bar{q}q\bar{s}b$ systems
are also obtained within the energy regions $2.4-3.4$ GeV and $5.7-6.7$ GeV,
respectively. The predicted exotic states, which are an indication of a richer
color structure when going towards multiquark systems beyond mesons and
baryons, are expected to be confirmed in future high-energy particle and
nuclear experiments.",2311.10376v1
2024-01-17,Effects of Vanadium Doping on the Optical Response and Electronic Structure of WS$_{2}$ Monolayers,"Two-dimensional dilute magnetic semiconductors has been recently reported in
semiconducting transition metal dichalcogenides by the introduction of
spin-polarized transition metal atoms as dopants. This is the case of
vanadium-doped WS$_2$ and WSe$_2$ monolayers, which exhibits a ferromagnetic
ordering even above room temperature. However, a broadband characterization of
their electronic band structure and its dependence on vanadium concentration is
still lacking. Therefore, here we perform power-dependent photoluminescence,
resonant four-wave mixing, and differential reflectance spectroscopy to study
the optical transitions close to the A exciton energy of vanadium-doped WS$_2$
monolayers with distinct concentrations. Instead of a single A exciton peak,
vanadium-doped samples exhibit two photoluminescence peaks associated with
transitions to occupied and unoccupied bands. Moreover, resonant Raman
spectroscopy and resonant second-harmonic generation measurements revealed a
blueshift in the B exciton but no energy change in the C exciton as vanadium is
introduced in the monolayers. Density functional theory calculations showed
that the band structure is sensitive to the Hubbard \(U\) correction for
vanadium and several scenarios are proposed to explain the two
photoluminescence peaks around the A exciton energy region. Our work provides
the first broadband optical characterization of these two-dimensional dilute
magnetic semiconductors, shedding light on the novel electronic features of
WS$_{2}$ monolayers which are tunable by the vanadium concentration.",2401.09402v1
2004-10-29,Resonances in $J/ψ\to φπ^+π^-$ and $φK^+K^-$,"A partial wave analysis is presented of $J/\psi \to \phi \pi ^+\pi ^-$ and
$\phi K^+K^-$ from a sample of 58M $J/\psi$ events in the BES II detector. The
$f_0(980)$ is observed clearly in both sets of data, and parameters of the
Flatt\' e formula are determined accurately: $M = 965 \pm 8$ (stat) $\pm 6$
(syst) MeV/c$^2$, $g_1 = 165 \pm 10 \pm 15 $ MeV/c$^2$, $g_2/g_1 = 4.21 \pm
0.25 \pm 0.21$. The $\phi \pi \pi$ data also exhibit a strong $\pi \pi$ peak
centred at $M = 1335$ MeV/c$^2$. It may be fitted with $f_2(1270)$ and a
dominant $0^+$ signal made from $f_0(1370)$ interfering with a smaller
$f_0(1500)$ component. There is evidence that the $f_0(1370)$ signal is
resonant, from interference with $f_2(1270)$. There is also a state in $\pi
\pi$ with $M = 1790 ^{+40}_{-30}$ MeV/c$^2$ and $\Gamma = 270 ^{+60}_{-30}$
MeV/c$^2$; spin 0 is preferred over spin 2. This state, $f_0(1790)$, is
distinct from $f_0(1710)$. The $\phi K\bar K$ data contain a strong peak due to
$f_2'(1525)$. A shoulder on its upper side may be fitted by interference
between $f_0(1500)$ and $f_0(1710)$.",0411001v2
2009-07-16,Renormalization of Commensurate Magnetic Peak in Ni-doped La$_{1.85}$Sr$_{0.15}$CuO$_{4}$,"We have studied the magnetic excitations in impurity doped
La$_{1.85}$Sr$_{0.15}$Cu$_{1-y}$A$_{y}$O$_{4}$ (A=Ni or Zn) by neutron
scattering. The dispersion for Zn:$y=0.017$ is similar to that for the impurity
free sample: incommensurate peaks with the incommensurability
$\delta=0.12\pm0.01$ (rlu) do not change their positions up to 21 meV. On the
other hand, for Ni:$y=0.029$, two incommensurate peaks observed at low energies
suddenly change into a broad commensurate peak at $E_\mathrm{cross}=15$ meV.
Compared to the impurity free sample with a similar Sr-concentration $x=0.16$,
[B. Vignolle {\it et al.} Nature Physics {\bf 3} (2007) 163],
$E_\mathrm{cross}$ for Ni:$y=0.029$ is decreased by nearly the same factor for
the reduction in $T_{c}$. This is very similar to the shift of the resonance
energy ($E_\mathrm{res}$) in Ni-doped YBa$_{2}$Cu$_{3}$O$_{7}$.[Y. Sidis {\it
et al.}: Phys. Rev. Lett. {\bf 84} (2000) 5900]. These common impurity effects
on the shift of $E_\mathrm{cross}$ and $E_\mathrm{res}$ suggest the same
magnetic origin for the resonance peak in YBa$_{2}$Cu$_{3}$O$_{\delta}$ and
that for a crossing point of upward and downward dispersions in the
La$_{2-x}$Sr$_{x}$CuO$_{4}$. We propose that the sudden change in the
dispersion is better described by a crossover from incommensurate spin
fluctuations to a gapped spin wave rather than a hourglass-like dispersion.",0907.2742v1
2011-12-15,Nuclear Magnetic Resonance Studies of Vortices in High Temperature Superconductors,"The distinct distribution of local magnetic fields due to superconducting
vortices can be detected with nuclear magnetic resonance (NMR) and used to
investigate vortices and related physical properties of extreme type II
superconductivity. This review summarizes work on high temperature
superconductors (HTS) including cuprates and pnictide materials. Recent
experimental results are presented which reveal the nature of vortex matter and
novel electronic states. For example, the NMR spectrum has been found to
provide a sharp indication of the vortex melting transition. In the vortex
solid a frequency dependent spin-lattice relaxation has been reported in
cuprates, including YBa$_2$Cu$_3$O$_{7-x}$, Bi$_2$SrCa$_2$Cu$_2$O$_{8+\delta}$,
and Tl$_2$Ba$_2$CuO$_{6+\delta}$. These results have initiated a new
spectroscopy via Doppler shifted nodal quasiparticles for the investigation of
vortices. At very high magnetic fields this approach is a promising method for
the study of vortex core excitations. These measurements have been used to
quantify an induced spin density wave near the vortex cores in
Bi$_2$SrCa$_2$Cu$_2$O$_{8+\delta}$. Although the cuprates have a different
superconducting order parameter than the iron arsenide superconductors there
are, nonetheless, some striking similarities between them regarding vortex
dynamics and frequency dependent relaxation.",1112.3632v1
2012-07-04,The COMPASS Hadron Spectroscopy Programme,"COMPASS is a fixed-target experiment at the CERN SPS for the investigation of
the structure and the dynamics of hadrons. The experimental setup features a
large acceptance and high momentum resolution spectrometer including particle
identification and calorimetry and is therefore ideal to access a broad range
of different final states. Following the promising observation of a spin-exotic
resonance during an earlier pilot run, COMPASS focused on light-quark hadron
spectroscopy during the years 2008 and 2009. A data set, world leading in terms
of statistics and resolution, has been collected with a 190GeV/c hadron beam
impinging on either liquid hydrogen or nuclear targets. Spin-exotic meson and
glueball candidates formed in both diffractive dissociation and central
production are presently studied. Since the beam composition includes protons,
the excited baryon spectrum is also accessible. Furthermore, Primakoff
reactions have the potential to determine radiative widths of the resonances
and to probe chiral perturbation theory. An overview of the ongoing analyses
will be presented. In particular, the employed partial wave analysis techniques
will be illustrated and recent results will be shown for a selection of final
states.",1207.0952v2
2013-08-28,Qubit noise spectroscopy using a continuous driving field,"The optimization of dynamical decoupling and quantum error correction for a
particular qubit realization is based on a detailed knowledge of the noise
properties. Spectroscopy of single-axis noise using dynamical decoupling pulse
sequences has garnered much recent attention. Here we consider noise
spectroscopy based on a spin-locking type pulse sequence, i.e. a
continuous-wave (CW) on-resonance driving field. We show that a heuristic
filter function approach produces a qualitatively correct (but quantitatively
incorrect) result, whereas a 0th-order average Hamiltonian calculation is shown
to agree with the result predicted by the generalized Bloch equations. We
further calculate up to 2nd-order average Hamiltonian corrections and show the
deviation from the generalized Bloch equation result. This shows that noise
spectroscopy using continuous fields, in some cases simpler to implement and
more robust to errors than pulsed schemes, can be rigorously analyzed and
criteria for reliable measurements can be established. Finally, a solid-state
nuclear magnetic resonance experiment is presented which demonstrates that the
CW and pulsed methods agree within experimental error. The noise, due to
magnetization fluctuations in a dipolar coupled proton spin bath, is found to
obey a roughly 1/\omega\ power law decay in the range of frequencies \omega\
investigated.",1308.6310v2
2018-06-29,Revealing the hidden order in BaTi2As2O via nuclear magnetic resonance,"In low-dimensional metallic systems, lattice distortion is usually coupled to
a density-wave-like electronic instability due to Fermi surface nesting (FSN)
and strong electron-phonon coupling. However, the ordering of other electronic
degrees of freedom can also occur simultaneously with the lattice distortion
thus challenges the aforementioned prevailing scenario. Recently, a hidden
electronic reconstruction beyond FSN was revealed in a layered metallic
compound BaTi2As2O below the structural transition temperature Ts ~ 200 K. The
nature of this hidden electronic instability is under strong debate. Here, by
measuring the local orbital polarization through 75As nuclear magnetic
resonance experiment, we observe a p-d bond order between Ti and As atoms in
BaTi2As2O single crystal. Below Ts, the bond order breaks both rotational and
translational symmetry of the lattice. Meanwhile, the spin-lattice relaxation
measurement indicates a substantial loss of density of states and an enhanced
spin fluctuation in the bond-order state. Further first-principles calculations
suggest that the mechanism of the bond order is due to the coupling of lattice
and nematic instabilities. Our results strongly support a bond-order driven
electronic reconstruction in BaTi2As2O and shed light on the mechanism of
superconductivity in this family.",1806.11272v1
2021-10-05,Ultrahigh nitrogen-vacancy center concentration in diamond,"High concentration of negatively charged nitrogen-vacancy ($\text{NV}^{-}$)
centers was created in diamond single crystals containing approximately 100 ppm
nitrogen using electron and neutron irradiation and subsequent thermal
annealing in a stepwise manner. Continuous wave electron paramagnetic resonance
(EPR) was used to determine the transformation efficiency from isolated N atoms
to $\text{NV}^{-}$ centers in each production step and its highest value was as
high as 17.5 %. Charged vacancies are formed after electron irradiation as
shown by EPR spectra, but the thermal annealing restores the sample quality as
the defect signal diminishes. We find that about 25 % of the vacancies form NVs
during the annealing process. The large $\text{NV}^{-}$ concentration allows to
observe orientation dependent spin-relaxation times and also the determination
of the hyperfine and quadrupole coupling constants with high precision using
electron spin echo (ESE) and electron-nuclear double resonance (ENDOR). We also
observed the EPR signal associated with the so-called W16 centers, whose
spectroscopic properties might imply a nitrogen dimer-vacancy center for its
origin.",2110.02126v2
2022-11-01,Calculated electron paramagnetic resonance $g$-tensor and hyperfine parameters for zinc vacancy and N related defects in ZnO,"Various defects in ZnO, focused on substitutional N$_O$ and N$_2$ in various
sites, O-site, interstitial and Zn-site are studied using first-principles
calculations with the goal of understanding the electron paramagnetic resonance
(EPR) center reported for N$_2$ in ZnO and substitutional N on the O-site. The
$g$ tensors are calculated using the gauge including projector augmented wave
(GIPAW) method and compared with experiments. The $g$-tensor of the free
N$_2^+$ and N$_2^-$ radicals and their various contributions within the GIPAW
theory are analyzed first to provide a baseline reference for the accuracy of
the method and for understanding the N$_2$ behavior in ZnO. Previous
controversies on the site location of N$_2$ in ZnO for this EPR center and on
the shallow or deep nature and donor or acceptor nature of this center are
resolved. We find that the N$_2$ on the Zn site is mostly zinc-vacancy like in
its spin density and $g$-tensor, while for the O-site, a model with the N$_2$
axis lying in-the basal plane and the singly occupied $\pi_g$-orbital along the
{\bf c} axis provides good agreement with experiment. For the interstitial
location, if the N$_2$ is not strongly interacting with the surroundings, no
levels in the gap are found and hence also no possible EPR center. The
calculated $g$-tensors for N$_O$ and $V_ Zn$ are also found to be in good
agreement with experiment. The effects of different functionals affecting the
localization of the spin density are shown to affect the $g$-tensor values.",2211.00469v1
2022-12-20,Efficient and all-carbon electrical readout of a NV based quantum sensor,"The spin readout of an ensemble of nitrogen-vacancy (NV) centers in diamond
can be realized by a photoconductive detection that is a complementary method
to the optical detection of the NV electron spin magnetic resonance. Here, we
implement the photoconductive detection through graphitic planar electrodes
that collect the photocurrent. Graphitic electrodes are patterned using a xenon
Focused-Ion Beam on an Optical-Grade quality diamond crystal containing a
nitrogen concentration of ~1 ppm and a NV concentration of a few ppb.
Resistance and current-voltage characteristics of the NV-doped diamond junction
are investigated tuning the 532 nm pump beam intensity. The junction has an
ohmic behavior and under a strong bias field, we observe velocity saturation of
the optically-induced carriers in the diamond junction. We perform the
photoconductive detection in continuous-wave regime of the magnetic resonance
of the NV centers ensemble for a magnetic field applied along the <100> and the
<111> direction with a magnitude above 100 mT. This technique enables the
realization of all-carbon diamond quantum sensors integrating graphitic
microstructures for the electrical readout.",2212.10349v1
2023-07-12,Charge response function probed by resonant inelastic x-ray scattering: the signature of electronic gaps of YBa$_2$Cu$_3$O$_{7-δ}$,"In strongly correlated systems the complete determination of the dynamical
susceptibility $\chi(\textbf{q}, \omega)$ is of special relevance because of
the entwinement of the spin and charge components. Although Resonant Inelastic
X-Ray Scattering (RIXS) spectra are directly related to both the charge
($\chi''_c(\textbf{q}, \omega)$) and the spin ($\chi''_s(\textbf{q}, \omega)$)
contributions, only the latter has been extensively studied with RIXS so far.
Here we show how to extract from RIXS spectra of high-$T_c$ superconducting
cuprates relevant properties of $\chi''_c$, such as the presence of the
superconducting gap and of the pseudogap. In particular, we exploit the
temperature dependence of the Cu L$_3$ edge RIXS spectra of underdoped
YBa$_2$Cu$_3$O$_{7-\delta}$ at specific wave-vectors q. The signature of the
two gaps is in the departure of the low energy Bosonic excitation continuum
from the statistical temperature-dependence. This approach can be immediately
used to investigate systematically the nature of the pseudogap in cuprates,
thereby taking advantage of the RIXS technique that does not suffer the
limitations of surface-sensitive electron spectroscopies. Its extension to
other interesting materials is foreseen.",2307.06375v1
2007-05-25,Inductively Coupled Circuits with Spin Wave Bus for Information Processing,"We describe a new approach to logic devices interconnection by the inductive
coupling via a ferromagnetic film. The information among the distant devices is
transmitted in a wireless manner via a magnetic field produced by spin waves
propagating in the ferromagnetic film, referred to as the spin wave bus. As an
alternative approach to the transistor-based architecture, logic circuits with
spin wave bus do not use charge as an information carrier. A bit of information
can be encoded into the phase or the amplitude of the spin wave signal. We
present experimental data demonstrating inductive coupling through the 100nm
thick NiFe and CoFe films at room temperature. The performance of logic
circuits with spin wave bus is illustrated by numerical modeling based on the
experimental data. Potentially, logic circuits with spin wave bus may resolve
the interconnect problem and provide ""wireless"" read-in and read-out. Another
expected benefit is in the enhanced logic functionality. A set of NOT, AND, and
OR logic gates can be realized in one device structure. The coupling between
the circuits and the spin wave bus can be controlled. We present the results of
numerical simulations showing the controllable switching of a bi-stable logic
cell inductively coupled to the spin wave bus. The shortcomings and limitations
of circuits with spin wave bus are also discussed.",0705.3864v1
2019-01-06,Asymmetric dynamics of edge exchange spin waves in honeycomb nanoribbons with zigzag and bearded edges boundaries,"We report on the theoretical prediction of asymmetric edge spin waves,
propagating in opposite directions on the edges of honeycomb nanoribbons with
zigzag and bearded edges boundaries. The simultaneous propagation of edge spin
waves in the same direction on both edges of these nanoribbons is hence
predicted to be forbidden. These asymmetric edge exchange spin waves are
analogous to the nonreciprocal surface spin waves reported in magnetic thin
films. Their existence is related to the nontrivial symmetry underlying the
nanoribbons under study. The edge and discretized bulk exchange spin waves are
calculated in the long wavelength part of the Brillouin zone using the
classical spin wave theory approach and appropriate boundary conditions. In the
absence of an external magnetic field in our study, the asymmetric edge spin
waves propagate with equal frequencies and opposite directions, since the
energy dispersion relation is independent of the sign of the wavevector
components in the long wavelength part of the Brillouin zone. The edge spin
waves are characterized by linear dispersion relations for magnetically
isotropic nanoribbons. Introducing magnetic anisotropy in the calculation
significantly enhances the energy gap between the edge and bulk spin waves in
both types of nanoribbons. Based on our calculation, the large energy gap
allows separate excitation of bulk and edge modes as their energies are no more
overlapping.",1901.01617v1
2016-06-23,Spin-Hall nano-oscillator with oblique magnetization and Dzyaloshinskii-Moriya interaction as generator of skyrmions and nonreciprocal spin-waves,"Spin-Hall oscillators are promising sources of spin-wave signals for
magnonics applications, and can serve as building blocks for magnonic logic in
ultralow power computation devices. Here, we analytically and micromagnetically
study magnetization dynamics excited in a Spin-Hall oscillator with oblique
magnetization when the spin-Hall effect and interfacial Dzyaloshinskii-Moriya
interaction act simultaneously. Our key results are (i) excitation of
nonreciprocal spin-waves propagating perpendicularly to the in-plane projection
of the static magnetization, (ii) skyrmions generation by pure spin-current,
(iii) excitation of a new spin-wave mode with a spiral spatial profile
originating from a gyrotropic rotation of a dynamical skyrmion. These results
demonstrate that Spin-Hall oscillators can be used as generators of magnetic
skyrmions and different types of propagating spin-waves for magnetic data
storage and signal processing applications.",1606.07280v1
1998-01-11,The Effects of Correlations on Neutrino Opacities in Nuclear Matter,"Including nucleon-nucleon correlations due to both Fermi statistics and
nuclear forces, we have developed a general formalism for calculating the
neutral-current neutrino-nucleon opacities in nuclear matter. We derive
corrections to the dynamic structure factors due to both density and spin
correlations and find that neutrino-nucleon cross sections are suppressed by
large factors around and above nuclear density. In addition, we find that the
spectrum of energy transfers in neutrino scattering is considerably broadened
by the interactions in the medium. An identifiable component of this broadening
comes from the absorption and emission of quanta of collective modes akin to
the Gamow-Teller and Giant Dipole resonances in nuclei (zero-sound; spin
waves), with \v{C}erenkov kinematics. Under the assumption that both the
charged-current and the neutral-current cross sections are decreased by
many-body effects, we calculate a set of ad hoc protoneutron star cooling
models to gauge the potential importance of the new opacities to the supernova
itself. We find that after many hundreds of milliseconds to seconds the driving
neutrino luminosities might be increased by from 10% to 100%. However, the
actual consequences, if any, of these new neutrino opacities remain to be
determined.",9801082v1
1999-08-02,Skyrmion Dynamics and NMR Line Shapes in QHE Ferromagnets,"The low energy charged excitations in quantum Hall ferromagnets are
topological defects in the spin orientation known as skyrmions. Recent
experimental studies on nuclear magnetic resonance spectral line shapes in
quantum well heterostructures show a transition from a motionally narrowed to a
broader `frozen' line shape as the temperature is lowered at fixed filling
factor. We present a skyrmion diffusion model that describes the experimental
observations qualitatively and shows a time scale of $\sim 50 \mu{\rm sec}$ for
the transport relaxation time of the skyrmions. The transition is characterized
by an intermediate time regime that we demonstrate is weakly sensitive to the
dynamics of the charged spin texture excitations and the sub-band electronic
wave functions within our model. We also show that the spectral line shape is
very sensitive to the nuclear polarization profile along the z-axis obtained
through the optical pumping technique.",9908029v2
2000-08-01,Direct Observation of the Quantum Energy Gap in S = 1/2 Tetragonal Cuprate Antiferromagnets,"Using an electron spin resonance spectrometer covering a wide range of
frequency and magnetic field, we have measured the low energy excitations of
the S=1/2 tetragonal antiferromagnets, Sr_{2}CuO_{2}Cl_{2} and
Sr_{2}Cu_{3}O_{4}Cl_{2}. Our observation of in-plane energy gaps of order 0.1
meV at zero external magnetic field are consistent with a spin wave
calculation, which includes several kinds of quantum fluctuations that remove
frustration. Results agree with other experiments and with exchange anisotropy
parameters determined from a five band Hubbard model.",0008009v1
2002-11-29,Structure of end states for a Haldane Spin Chain,"Inelastic neutron scattering was used to probe edge states in a quantum spin
liquid. The experiment was performed on finite length antiferromagnetic spin-1
chains in Y_2BaNi_{1-x}Mg_xO_5. At finite fields, there is a Zeeman resonance
below the Haldane gap. The wave vector dependence of its intensity provides
direct evidence for staggered magnetization at chain ends, which decays
exponentially towards the bulk (xi = 8(1) at T=0.1K). Continuum contributions
to the chain end spectrum indicate inter-chain-segment interactions. We also
observe a finite size blue shift of the Haldane gap.",0211703v1
2004-10-01,Magnetic Properties of Cuprate Perovskites,"The magnetic susceptibility of underdoped yttrium and lanthanum cuprates is
interpreted based on the self-consistent solution of the t-J model of a Cu-O
plane. The calculations reproduce correctly the frequency dependencies of the
susceptibility in YBa2Cu3O_{7-y} and La_{2-x}Sr_xCuO4 attributing their
dissimilarity to the difference in the damping of spin excitations. In
YBa2Cu3O_{7-y} these excitations are well defined at the antiferromagnetic wave
vector Q=(\pi,\pi) even in the normal state which manifests itself in a
pronounced maximum -- the resonance peak -- in the susceptibility. In
La_{2-x}Sr_xCuO4 the spin excitations are overdamped which leads to a broad
low-frequency feature in the susceptibility. The low-frequency
incommensurability in the magnetic response is attributed to a dip in the
magnon damping at Q. The calculated concentration and temperature dependencies
of the incommensurability parameter conform with experimental observations.
Generally the incommensurate magnetic response is not accompanied with an
inhomogeneity of the carrier density.",0410009v1
2005-07-21,Low frequency Rabi spectroscopy for a dissipative two-level system,"We have analyzed the interaction of a dissipative two level quantum system
with high and low frequency excitation. The system is continuously and
simultaneously irradiated by these two waves. If the frequency of the first
signal is close to the level separation the response of the system exhibits
undamped low frequency oscillations whose amplitude has a clear resonance at
the Rabi frequency with the width being dependent on the damping rates of the
system. The method can be useful for low frequency Rabi spectroscopy in various
physical systems which are described by a two level Hamiltonian, such as nuclei
spins in NMR, double well quantum dots, superconducting flux and charge qubits,
etc. As the examples, the application of the method to a nuclear spin and to
the readout of a flux qubit are briefly discussed.",0507502v2
2006-02-23,Dynamical magneto-electric coupling in helical magnets,"Collective mode dynamics of the helical magnets coupled to electric
polarization via spin-orbit interaction is studied theoretically. The soft
modes associated with the ferroelectricity are not the transverse optical
phonons, as expected from the Lyddane-Sachs-Teller relation, but are the spin
waves hybridized with the electric polarization. This leads to the Drude-like
dielectric function $\epsilon(\omega)$ in the limit of zero magnetic
anisotropy. There are two more low-lying modes; phason of the spiral and
rotation of helical plane along the polarization axis. The roles of these soft
modes in the neutron scattering and antiferromagnetic resonance are revealed,
and a novel experiment to detect the dynamical magneto-electric coupling is
proposed.",0602547v1
1999-03-15,Covariant amplitudes for mesons,"We show how to construct covariant amplitudes for processes involving higher
spins in this paper. First we give the explicit expressions of Rarita-Schwinger
wave functions and propagators for bosons with spins, then kinematic
singularity free 3-leg effective vertexes are derived and given in a list.
Equivalence relations are worked out to get these independent vertexes.
Constraints of space reflection symmetry and boson symmetry are considered and
shown in a explicit way. Some helicity amplitudes for two-body decays in center
of frame are calculated. Finally the covariant helicity amplitudes for the
process $a_1\to \pi^+\pi^+\pi^-$ are constructed to illustrate how to include
background (1PI) amplitudes. Both background amplitudes and resonance
amplitudes are needed to give reliable descriptions to high energy reactions.",9903349v1
1999-09-10,Scalar absorption by spinning D3-branes,"We discuss absorption of scalars by a distribution of spinning D3-branes. The
D3-branes are multi-center solutions of supergravity theory. We solve the wave
equation in various cases of supergravity backgrounds in which the equation
becomes separable. We show that the absorption coefficients exhibit a universal
behavior as functions of the angular momentum quantum number and the Hawking
temperature. This behavior is similar to the form of the gray-body factors one
encounters in scattering by black-holes. Our discussion includes the
problematic case of spherically symmetric distributions of D-branes, where
resonances arise. We obtain the same universal form for the absorption
coefficients, if the region enclosed by the D-branes is excluded from physical
considerations. Non-extremal D-branes are also discussed. The results are
similar to the extremal cases, albeit at half the Hawking temperature. We
speculate that new degrees of freedom enter as one moves away from extremality.",9909071v1
1999-08-16,Dynamical Test of Constituent Quark Models with $πN$ Reactions,"A dynamical approach is developed to predict the $\pi N$ scattering
amplitudes starting with the constituent quark models. The first step is to
apply a variational method to solve the three-quark bound state problem. The
resulting wave functions are used to calculate the $N^* \to \pi N, \eta N,
\pi\Delta$ vertex functions by assuming that the $\pi$ and $\eta$ mesons couple
directly to quarks. These vertex functions and the predicted baryon bare masses
then define a Hamiltonian for $\pi N$ reactions. We apply a unitary
transformation method to derive from the constructed Hamiltonian a
multi-channel and multi-resonance reaction model for predicting the $\pi N$
scattering amplitudes up to $W = 2$ GeV. With the parameters constrained by the
$\Delta(1232$) excitation, we have examined the extent to which the $\pi N$
scattering in $S_{11}$ channel can be described by the constituent quark models
based on the one-gluon-exchange or one-meson-exchange mechanisms. It is found
that the data seem to favor the spin-spin interaction due to one-meson-exchange
and the tensor interaction due to one-gluon-exchange. A phenomenological
quark-quark potential has been constructed to reproduce the $S_{11}$ amplitude.",9908048v1
2001-06-22,Interactions between Octet Baryons in the SU_6 Quark model,"The baryon-baryon interactions for the complete baryon octet (B_8) are
investigated in a unified framework of the resonating-group method, in which
the spin-flavor SU_6 quark-model wave functions are employed. Model parameters
are determined to reproduce properties of the nucleon-nucleon system and the
low-energy cross section data for the hyperon-nucleon interaction. We then
proceed to explore B_8 B_8 interactions in the strangeness S=-2, -3 and -4
sectors. The S-wave phase-shift behavior and total cross sections are
systematically understood by 1) the spin-flavor SU_6 symmetry, 2) the special
role of the pion exchange, and 3) the flavor symmetry breaking.",0106052v2
2005-12-21,Variational Monte Carlo study of pentaquark states in a correlated quark model,"Accurate numerical solution of the five-body Schrodinger equation is effected
via variational Monte Carlo in a correlated quark model. The spectrum is
assumed to exhibit a narrow resonance with strangeness S=+1. A fully
antisymmetrized and pair-correlated five-quark wave function is obtained for
the assumed non-relativistic Hamiltonian which has spin, isospin, and color
dependent pair interactions and many-body confining terms which are fixed by
the non-exotic spectra. Gauge field dynamics are modeled via flux tube exchange
factors. The energy determined for the ground states with spin-parity 1/2-
(1/2+) is 2.22 GeV (2.50 GeV). A lower energy negative parity state is
consistent with recent lattice results.",0512085v1
2006-01-05,Structure and decay width of Θ^+ in a one-gluon exchange model,"The mass and decay width of the $\Theta^+(1540)$ with isospin 0 are
investigated in a constituent quark model comprising $uudd\bar{s}$ quarks. The
resonance state for the $\Theta^+$ is identified as a stable solution in
correlated basis calculations. With the use of a one-gluon exchange quark-quark
interaction, the mass is calculated to be larger than 2 GeV, increasing in
order of the spin-parity, ${1/2}^-, {3/2}^-$ and ${1/2}^+ ({3/2}^+)$, and only
the ${3/2}^-$ state has a small width to the $nK^{*+}$ decay. If the calculated
mass is shifted to around 100 MeV above the $N+K$ threshold, the
$\Theta^+(1540)$ is possibly ${1/2}^+ ({3/2}^+)$ or ${3/2}^-$, though in the
latter case it cannot decay to the $nK^{+}$ channel. In addition it is
conjectured that other pentaquark state with different spin-parity exists below
the $\Theta^+(1540)$. The structure of the $\Theta^+$ is discussed through the
densities and two-particle correlation functions of the quarks and through the
wave function decomposition to a baryon-meson model and a diquark-pair model.",0601011v1
2004-11-11,Multimode entanglement of light and atomic ensembles via off-resonant coherent forward scattering,"Quantum theoretical treatment of coherent forward scattering of light in a
polarized atomic ensemble with an arbitrary angular momentum is developed. We
consider coherent forward scattering of a weak radiation field interacting with
a realistic multi-level atomic transition. Based on the concept of an effective
Hamiltonian and on the Heisenberg formalism, we discuss the coupled dynamics of
the quantum fluctuations of the polarization Stokes components of propagating
light and of the collective spin fluctuations of the scattering atoms. We show
that in the process of coherent forward scattering this dynamics can be
described in terms of a polariton-type spin wave created in the atomic sample.
Our work presents a general example of entangling process in the system of
collective quantum states of light and atomic angular momenta, previously
considered only for the case of spin-1/2 atoms. We use the developed general
formalism to test the applicability of spin-1/2 approximation for modelling the
quantum non-demolishing measurement of atoms with a higher angular momentum.",0411083v2
2006-07-06,Non-adiabatic Arbitary Geometric Gates in 2-qubit NMR Model,"We study a 2-qubit nuclear spin system for realizing an arbitrary geometric
quantum phase gate by means of non-adiabatic operation. A single magnetic pulse
with multi harmonic frequencies is applied to manipulate the quantum states of
2-qubit instantly. Using resonant transition approximation, the time dependent
Hamiltonian of two nuclear spins can be solved analytically. The time evolution
of the wave function is obtained without adiabatic approximation. The
parameters of magnetic pulse, such as the frequency, amplitude, phase of each
harmonic part as well as the time duration of the pulse, are determined for
achieving an arbitrary non-adiabatic geometric phase gate. The derivation of
non-adiabatic geometric controlled phase gates and A-A phase are also
addressed.",0607041v3
2007-11-20,Covariant Helicity-Coupling Amplitudes: A New Formulation,"We have worked out covariant amplitudes for any two-body decay of a resonance
with an arbitrary non-zero mass, which involves arbitrary integer spins in the
initial and the final states. One key new ingredient for this work is the
application of the total intrinsic spin operator $\vec S$ which is given
directly in terms of the generators of the Poincar\'e group.
  Using the results of this study, we show how to explore the Lorentz factors
which appear naturally, if the momentum-space wave functions are used to form
the covariant decay amplitudes. We have devised a method of constructing our
covariant decay amplitudes, such that they lead to the Zemach amplitudes when
the Lorentz factors are set one.",0711.3143v4
2007-12-04,Pressure dependence of the superconducting transition and electron correlations in Na_xCoO_2 \cdot 1.3H_2O,"We report T_c and ^{59}Co nuclear quadrupole resonance (NQR) measurements on
the cobalt oxide superconductor Na_{x}CoO_{2}\cdot 1.3H_{2}O (T_c=4.8 K) under
hydrostatic pressure (P) up to 2.36 GPa. T_c decreases with increasing pressure
at an average rate of -0.49\pm0.09 K/GPa. At low pressures P\leq0.49 GPa, the
decrease of T_c is accompanied by a weakening of the spin correlations at a
finite wave vector and a reduction of the density of states (DOS) at the Fermi
level. At high pressures above 1.93 GPa, however, the decrease of T_c is mainly
due to a reduction of the DOS. These results indicate that the
electronic/magnetic state of Co is primarily responsible for the
superconductivity. The spin-lattice relaxation rate 1/T_1 at P=0.49 GPa shows a
T^3 variation below T_c down to T\sim 0.12T_c, which provides compelling
evidence for the presence of line nodes in the superconducting gap function.",0712.0419v1
2008-05-07,"Neutron scattering study of the oxypnictide superconductor La(O,F)FeAs","The newly discovered superconductor La(O,F)FeAs (Tc = 26 K) was investigated
using the neutron scattering technique. No spin-density-wave (SDW) order was
observed in the normal state nor in the superconducting state, both with and
without an applied magnetic field of 9 T, consistent with the proposal that SDW
and superconductivity are competing in the laminar materials. While our
inelastic measurements offer no constraints on the spin dynamic response from
d-wave pairing, an upper limit for the magnetic resonance peak predicted from
an extended s-wave pairing mechanism is provided. Our measurements also support
the energy scale of the calculated phonon spectrum which is used in
electron-phonon coupling theory, and fails to produce the high observed Tc.",0805.1062v1
2008-05-19,QQ-onia package: a numerical solution to the Schrodinger radial equation for heavy quarkonium,"This paper presents the basics of the QQ-onia package, a software based upon
the Numerov method which can be used to solve the Schrodinger radial equation
using a suitable potential V(r) for the heavy quarkonium system. This package
also allows the analysis of relevant properties of those resonances such as the
wave functions at the origin, their corresponding derivatives for l \neq 0
states, typical heavy quark velocities, and mean square radii. Besides, it
includes a tool to analize the spin-dependent contributions to the heavy
quarkonia spectrum, providing the hyperfine splittings, as well as the nPJ
energy levels. Finally, a simple software implemented in QQ-onia to compute E1
transition rates is presented.",0805.2704v2
2010-04-17,"Low Energy, Coherent, Stoner-like Excitations in CaFe$_{2}$As$_{2}$","Using linear-response density-functional theory, magnetic excitations in the
striped phase of CaFe$_{2}$As$_{2}$ are studied as a function of local moment
amplitude. We find a new kind of excitation: sharp resonances of Stoner-like
(itinerant) excitations at energies comparable to the N{\'{e}}el temperature,
originating largely from a narrow band of Fe $d$ states near the Fermi level,
and coexist with more conventional (localized) spin waves. Both kinds of
excitations can show multiple branches, highlighting the inadequacy of a
description based on a localized spin model.",1004.2934v2
2010-08-23,Diffractive Dissociation of 190 GeV/c $π^-$ into $π^-π^+π^-$ Final States at COMPASS,"We present results from a Partial-Wave Analysis (PWA) of diffractive
dissociation of 190 GeV/c $\pi^-$ into $\pi^-\pi^+\pi^-$ final states on
nuclear targets. A PWA of the data sample taken during a COMPASS pilot run in
2004 on a Pb target showed a significant spin-exotic $J^{PC} = 1^{-+}$
resonance consistent with the controversial $\pi_1(1600)$, which is considered
to be a candidate for a non-$q\bar{q}$ mesonic state. In 2008 COMPASS collected
a large diffractive $\pi^-\pi^+\pi^-$ data sample using a hydrogen target. A
first comparison with the 2004 data shows a strong target dependence of the
production strength of states with spin projections $M = 0$ and 1.",1008.3838v2
2010-09-16,Effective interactions and long distance symmetries in the Nucleon-Nucleon system,"Effective interactions, when defined in a coarse grained sense, such as Vlowk
at the scale 450 MeV, display a remarkable symmetry pattern. Serber symmetry
works with high accuracy for spin triplet states. Wigner SU(4) spin-isospin
symmetry with nucleons in the fundamental representation works only for even
partial waves exactly as predicted by large Nc limit of QCD with accuracy
O(1/Nc^2). This suggests tailoring the very definition of effective
interactions to provide a best possible fulfillment of long distance
symmetries. With the Vlowk definition Wigner symmetry requires that chiral
potentials have low cut-offs (450 MeV). Perturbative saturation of heavy
mesonic resonances does not faithfully display the Serber symmetry pattern.",1009.3149v2
2011-12-31,"Ferromagnetic Ordering in Carbon Nanotubes, Incorporated in Diamond Single Crystals","The physical origin of the mechanism of the formation of ferromagnetic
ordering in carbon nanotubes (NTs), produced by high energy ion beam
modification of diamond single crystals in $\langle{110}\rangle$ and
$\langle{111}\rangle$ directions has been found. It is concluded from analysis
of experimental results on ferromagnetic spin wave resonance observed, that the
only $\pi$-electronic subsystem of given NTs is responsible for the appearance
of ferromagnetism. It is determined by asymmetry in spin density distribution
in Su-Schrieffer-Heeger (SSH) topological soliton lattice. The formation of SSH
topological soliton lattice is considered in the frames of generalized
SSH-model of organic conductors, in which $\pi$-electronic subsystem is
represented being to be 1D quantum Fermi liquid.
  The phenomenon of formation of uncompensated antiferromagnetic ordering
coexisting with superconductivity at room temperature in carbon nanotubes,
produced by high energy ion beam modification of diamond single crystals in
$\langle{100}\rangle$ direction is argued.",1201.0285v3
2012-01-18,Unraveling the spin polarization of the v = 5/2 fractional quantum Hall state,"The fractional quantum Hall (FQH) effect at filling factor v = 5/2 has
recently come under close scrutiny, as it may possess quasi-particle
excitations obeying nonabelian statistics, a property sought for topologically
protected quantum operations. Yet, its microscopic origin remains unidentified,
and candidate model wave functions include those with undesirable abelian
statistics. Here we report direct measurements of the electron spin
polarization of the v = 5/2 FQH state using resistively detected nuclear
magnetic resonance (NMR). We find the system to be fully polarized, which
unambiguously rules out the most-likely abelian contender and thus lends strong
support for the v = 5/2 state being nonabelian. Our measurements reveal an
intrinsically different nature of interaction in the first-excited Landau level
underlying the physics at v = 5/2.",1201.3737v1
2012-06-20,Lifetime of Gapped Excitations in a Collinear Quantum Antiferromagnet,"We demonstrate that local modulations of magnetic couplings have a profound
effect on the temperature dependence of the relaxation rate of optical magnons
in a wide class of antiferromagnets in which gapped excitations coexist with
acoustic spin waves. In a two-dimensional collinear antiferromagnet with an
easy-plane anisotropy, the disorder-induced relaxation rate of the gapped mode,
Gamma_imp=Gamma_0+A(TlnT)^2, greatly exceeds the magnon-magnon damping,
Gamma_m-m=BT^5, negligible at low temperatures. We measure the lifetime of
gapped magnons in a prototype XY antiferromagnet BaNi2(PO4)2 using a
high-resolution neutron-resonance spin-echo technique and find experimental
data in close accord with the theoretical prediction. Similarly strong effects
of disorder in the three-dimensional case and in noncollinear antiferromagnets
are discussed.",1206.4690v2
2012-07-19,Topological surface states scattering in Antimony,"In this work we study the topologically protected states of the Sb(111)
surface by using ab-initio transport theory. In the presence of a strong
surface perturbation we obtain standing-wave states resulting from the
superposition of spin-polarized surface states. By Fourier analysis, we
identify the underlying two dimensional scattering processes and the spin
texture. We find evidence of resonant transmission across surface barriers at
quantum well states energies and evaluate their lifetimes. Our results are in
excellent agreement with experimental findings. We also show that despite the
presence of a step edge along a different high symmetry direction, not yet
probed experimentally, the surface states exhibit unperturbed transmission
around the Fermi energy for states with near to normal incidence.",1207.4716v2
2012-07-25,Quantification of memory effects in the spin-boson model,"Employing a recently proposed measure for quantum non-Markovianity, we carry
out a systematic study of the size of memory effects in the spin-boson model
for a large region of temperature and frequency cutoff parameters. The dynamics
of the open system is described utilizing a second-order time-convolutionless
master equation without the Markov or rotating wave approximations. While the
dynamics is found to be strongly non-Markovian for low temperatures and
cutoffs, in general, we observe a special regime favoring Markovian behavior.
This effect is explained as resulting from a resonance between the system's
transition frequency and the frequencies of the dominant environmental modes.
We further demonstrate that the corresponding Redfield equation is capable of
reproducing the characteristic features of the non-Markovian quantum behavior
of the model.",1207.5968v1
2013-02-19,Magnetoelectric susceptibility tensor of multiferroic TbMnO3 with cycloidal antiferromagnetic structure in external field,"Magnetoelectric, dielectric and magnetic susceptibility tensors of
multiferroic TbMnO3 with cycloidal antiferromagnetic structure in external
electric and magnetic fields have been investigated with taking into account
dynamics of spin, electro-dipole and acoustic subsystems. All components of
tensors depend on values of external electric and magnetic fields. The
possibility of control of electrodynamic properties of multiferroic TbMnO3 with
cycloidal antiferromagnetic structure by external electric and magnetic fields
has been shown. The resonant interaction of spin, electro-dipole,
electromagnetic and acoustic waves in such material is observed.",1302.4515v1
2013-10-22,Frustrating antiferromagnetic exchange interactions enhance specific valence-bond-pair motifs,"We present variational results for the ground state of the antiferromagnetic
quantum Heisenberg model with frustrating next-nearest-neighbour interactions.
The trial wave functions employed are of resonating-valence-bond type,
elaborated to account for various geometric motifs of adjacent bond pairs. The
calculation is specialized to a square-lattice cluster consisting of just
sixteen sites, large enough that the system can accommodate nontrivial singlet
dimer correlations but small enough that exhaustive enumeration of states in
the total spin zero sector is still feasible. A symbolic computation approach
allows us to generate an algebraic expression for the expectation value of any
observable and hence to carry out the energy optimization exactly. While we
have no measurements that could unambiguously identify a spin liquid state in
the controversial region at intermediate frustration, we can say that the
bond-bond correlation factors that emerge do not appear to be consistent with
the existence of a columnar valence bond crystal. Furthermore, our results
suggest that the magnetically disordered region may accommodate two distinct
phases.",1310.6030v1
2014-10-30,Tunable Charge and Spin Order in PrNiO$_3$ Thin Films and Superlattices,"We have used polarized Raman scattering to probe lattice vibrations and
charge ordering in 12 nm thick, epitaxially strained PrNiO$_3$ films, and in
superlattices of PrNiO$_3$ with the band-insulator PrAlO$_3$. A carefully
adjusted confocal geometry was used to eliminate the substrate contribution to
the Raman spectra. In films and superlattices under tensile strain, which
undergo a metal-insulator transition upon cooling, the Raman spectra reveal
phonon modes characteristic of charge ordering. These anomalous phonons do not
appear in compressively strained films, which remain metallic at all
temperatures. For superlattices under compressive strain, the Raman spectra
show no evidence of anomalous phonons indicative of charge ordering, while
complementary resonant x-ray scattering experiments reveal antiferromagnetic
order associated with a modest increase in resistivity upon cooling. This
confirms theoretical predictions of a spin density wave phase driven by spatial
confinement of the conduction electrons.",1410.8323v1
2015-04-10,Computational Study of the Magnetic Structure of Na$_2$IrO$_3$,"The magnetic structure of honeycomb iridate Na$_2$IrO$_3$ is of paramount
importance to its exotic properties. The magnetic order is established
experimentally to be zigzag antiferromagnetic. However, the previous assignment
of ordered moment to the $\bm{a}$-axis is tentative. We examine the magnetic
structure of Na$_{2}$IrO$_{3}$ using first-principles methods. Our calculations
reveal that total energy is minimized when the zigzag antiferromagnetic order
is magnetized along $\bm{g}\approx\bm{a}+\bm{c}$. Such a magnetic configuration
is explained by adding anisotropic interactions to the nearest-neighbor
Kitaev-Heisenberg model. Spin-wave spectrum is also calculated, where the
calculated spin gap of $10.4$ meV can in principle be measured by future
inelastic neutron scattering experiments. Finally we emphasize that our
proposal is consistent with all known experimental evidence, including the most
relevant resonant x-ray magnetic scattering measurements [X. Liu \emph{et al.}
{Phys. Rev. B} \textbf{83}, 220403(R) (2011)].",1504.02699v1
2016-04-02,Relaxation-free and inertial switching in synthetic antiferromagnets subject to super-resonant excitation,"Applications of magnetic memory devices greatly benefit from ultra-fast,
low-power switching. Here we propose how this can be achieved efficiently in a
nano-sized synthetic antiferromagnet by using perpendicular-to-the-plane
picosecond-range magnetic field pulses. Our detailed micromagnetic simulations,
supported by analytical results, yield the parameter space where inertial
switching and relaxation-free switching can be achieved in the system. We
furthermore discuss the advantages of dynamic switching in synthetic
antiferromagnets and, specifically, their relatively low-power switching as
compared to that in single ferromagnetic particles. Finally, we show how
excitation of spin-waves in the system can be used to significantly reduce the
post-switching spin oscillations for practical device geometries.",1604.00559v2
2016-04-22,Analytical recursive method to ascertain multisite entanglement in doped quantum spin ladders,"We formulate an analytical recursive method to generate the wave function of
doped short-range resonating valence bond (RVB) states as a tool to efficiently
estimate multisite entanglement as well as other physical quantities in doped
quantum spin ladders. We prove that doped RVB ladder states are always genuine
multipartite entangled. Importantly, our results show that within specific
doping concentration and model parameter regimes, the doped RVB state
essentially characterizes the trends of genuine multiparty entanglement in the
exact ground states of the Hubbard model with large onsite interactions, in the
limit which yields the $t$-$J$ Hamiltonian.",1604.06683v2
2016-08-30,Strongly Gapped Spin-Wave Excitation in the Insulating Phase of NaOsO3,"NaOsO3 hosts a rare manifestation of a metal-insulator transition driven by
magnetic correlations, placing the magnetic exchange interactions in a central
role. We use resonant inelastic x-ray scattering to directly probe these
magnetic exchange interactions. A dispersive and strongly gapped (58 meV)
excitation is observed indicating appreciable spin-orbit coupling in this 5d3
system. The excitation is well described within a minimal model Hamiltonian
with strong anisotropy and Heisenberg exchange (J1=J2=13.9 meV). The observed
behavior places NaOsO3 on the boundary between localized and itinerant
magnetism.",1608.08477v2
2018-03-15,Electrometry by optical charge conversion of deep defects in 4H-SiC,"Optically-active point defects in various host materials, such as diamond and
silicon carbide (SiC), have shown significant promise as local sensors of
magnetic fields, electric fields, strain and temperature. Current sensing
techniques take advantage of the relaxation and coherence times of the spin
state within these defects. Here we show that the defect charge state can also
be used to sense the environment, in particular high frequency (MHz-GHz)
electric fields, complementing established spin-based techniques. This is
enabled by optical charge conversion of the defects between their
photoluminescent and dark charge states, with conversion rate dependent on the
electric field (energy density). The technique provides an all-optical high
frequency electrometer which is tested in 4H-SiC for both ensembles of
divacancies and silicon vacancies, from cryogenic to room temperature, and with
a measured sensitivity of ~41 (V/cm)**2 / $\sqrt{Hz}$. Finally, due to the
piezoelectric character of SiC, we obtain spatial 3D maps of surface acoustic
wave modes in a mechanical resonator.",1803.05956v1
2018-09-11,Polarization-driven spin precession of mesospheric sodium atoms,"We report experimental results on the first on-sky observation of atomic spin
precession of mesospheric sodium driven by polarization modulation of a
continuous-wave laser. The magnetic resonance was remotely detected from the
ground by observing the enhancement of induced fluorescence when the driving
frequency approached the precession frequency of sodium in the mesosphere,
between 85 km and 100 km altitude. The experiment was performed at La Palma,
and the uncertainty in the measured Larmor frequency ($\approx$260 kHz)
corresponded to an error in the geomagnetic field of 0.4 mG. The results are
consistent with geomagnetic field models and with the theory of light-atom
interaction in the mesosphere.",1809.03923v1
2019-11-18,Novel magnetic phase in a weakly ordered spin-1/2 chain antiferromagnet Sr$_2$CuO$_3$,"We present the magnetic phase diagram of a spin-1/2 chain antiferromagnet
Sr$_2$CuO$_3$ studied by ultrasound phase-sensitive detection technique. We
observe an enhanced effect of external magnetic field on the ordering
temperature of the system, which is in the extreme proximity to the quantum
critical point. Inside the N\'eel ordered phase, we detect an additional
field-induced continuous phase transition, which is unexpected for a collinear
Heisenberg antiferromagnet. This transition is accompanied by softening of
magnetic excitation mode observed by electron-spin resonance, which can be
associated with a longitudinal (amplitude) mode of the order parameter in a
weakly-coupled system of spin-1/2 chains. These results suggest transition from
a transverse collinear antiferromagnet to an amplitude-modulated spin density
wave phase induced by magnetic field.",1911.07592v1
2018-07-10,The dual nature of magnetism in a uranium heavy fermion system,"The duality between localized and itinerant nature of magnetism in
$5\textit{f}$ electron systems has been a longstanding puzzle. Here, we report
inelastic neutron scattering measurements, which reveal both local and
itinerant aspects of magnetism in a single crystalline system of
UPt$_{2}$Si$_{2}$. In the antiferromagnetic state, we observe broad continuum
of diffuse magnetic scattering with a resonance-like gap of $\approx$ 7 meV,
and surprising absence of coherent spin-waves, suggestive of itinerant
magnetism. While the gap closes above the Neel temperature, strong dynamic spin
correlations persist to high temperature. Nevertheless, the size and
temperature dependence of the total magnetic spectral weight can be well
described by local moment with $J=4$. Furthermore, polarized neutron
measurements reveal that the magnetic fluctuations are mostly transverse, with
little or none of the longitudinal component expected for itinerant moments.
These results suggest that a dual description of local and itinerant magnetism
is required to understand UPt$_{2}$Si$_{2}$, and by extension, other 5$f$
systems in general.",1807.03686v1
2014-06-24,Double-semion topological order from exactly solvable quantum dimer models,"We construct a generalized quantum dimer model on two-dimensional
nonbipartite lattices including the triangular lattice, the star lattice and
the kagome lattice. At the Rokhsar-Kivelson (RK) point, we obtain its exact
ground states that are shown to be a fully gapped quantum spin liquid with the
double-semion topological order. The ground-state wave function of such a model
at the RK point is a superposition of dimer configurations with a nonlocal sign
structure determined by counting the number of loops in the transition graph.
We explicitly demonstrate the double-semion topological order in the ground
states by showing the semionic statistics of monomer excitations. We also
discuss possible implications of such double-semion resonating valence bond
states to candidate quantum spin-liquid systems discovered experimentally and
numerically in the past few years.",1406.6364v3
2018-12-11,A Clock Transition in the Cr$_7$Mn Molecular Nanomagnet,"A viable qubit must have a long coherence time $T_2$. In molecular
nanomagnets $T_2$ is often limited at low temperatures by the presence of
dipole and hyperfine interactions, which are often mitigated through sample
dilution, chemical engineering and isotope substitution in synthesis.
Atomic-clock transitions offer another route to reducing decoherence from
environmental fields by reducing the effective susceptibility of the working
transition to field fluctuations. The Cr$_7$Mn molecular nanomagnet, a
heterometallic ring, features a clock transition at zero field. Both
continuous-wave and spin-echo electron-spin resonance experiments on Cr$_7$Mn
samples diluted via co-crystallization, show evidence of the effects of the
clock transition with a maximum $T_2\sim350$ ns at 1.8 K. We discuss
improvements to the experiment that may increase $T_2$ further.",1812.04449v1
2019-02-20,Gapless spin excitations in superconducting La$_{2-x}$Ca$_{1+x}$Cu$_{2}$O$_{6}$ with $T_c$ up to 55 K,"We report inelastic neutron scattering on single crystals of the bilayer
cuprate family La$_{2-x}$Ca$_{1+x}$Cu$_{2}$O$_{6+\delta}$, including two
crystals made superconducting (transitions at 45 and 55 K) by high-pressure
annealing in an oxygen-containing atmosphere. The magnetic excitations in the
non-superconducting crystal have a similar temperature-dependence as those in
weakly hole-doped cuprates. In the superconducting crystals, there is a
near-uniform suppression of the magnetic spectral weight with increasing
temperature; in particular, there are no signs of a spin gap or ""resonance""
peak. This is different from the temperature dependence seen in many
optimally-doped cuprates but similar to the behavior seen in certain underdoped
cuprates. We discuss the possible connection with pair-density-wave
superconductivity.",1902.07799v2
2020-04-05,Magnon spectrum and electron spin resonance in antiferromagnet with large single-ion easy plane anisotropy,"Motivated by recent experiments on quantum magnet
NiCl$_{2}$-4SC(NH$_{2}$)$_{2}$ (DTN) and its Br-doped counterpart DTNX we
propose a theoretical description of optical magnon branch in the
antiferromagnet with large single-ion anisotropy in the magnetically ordered
phase. In the framework of the 1/S expansion we derive analytical expressions
for optical magnon with $\mathbf{k}=0$ energy magnetic field dependence
$\Delta(h)$. It is shown that in the linear spin wave approximation $\Delta(h)$
is monotonic without extrema whereas first order in 1/S corrections makes it
drastically different function with a minimum near the center of magnetically
ordered phase. The latter behaviour was observed in ESR experiments. Moreover,
we show that $\Delta(h)$ has nontrivial dependence on the system parameters. It
solves the discrepancy between inelastic neutron scattering data where the
growth of interaction constants in DTNX with small Br concentration was
observed and ESR experiments showing almost unchanged $\Delta(h)$ in comparison
with pure DTN.",2004.02170v2
2016-03-30,A spin integral equation for electromagnetic and acoustic scattering,"We present a new integral equation for solving the Maxwell scattering problem
against a perfect conductor. The very same algorithm also applies to sound-soft
as well as sound-hard Helmholtz scattering, and in fact the latter two can be
solved in parallel in three dimensions. Our integral equation does not break
down at interior spurious resonances, and uses spaces of functions without any
algebraic or differential constraints. The operator to invert at the boundary
involves a singular integral operator closely related to the three dimensional
Cauchy singular integral, and is bounded on natural function spaces and depend
analytically on the wave number. Our operators act on functions with pairs of
complex two by two matrices as values, using a spin representation of the
fields.",1603.09091v2
2021-04-02,Site-dependent selection of atoms for homogeneous atom-cavity coupling,"We demonstrate a method to obtain homogeneous atom-cavity coupling by
selecting and keeping $^{87}$Rb atoms that are near maximally coupled to the
cavity's standing-wave mode. We select atoms by imposing an AC Stark shift on
the ground state hyperfine microwave transition frequency with light injected
into the cavity. We then induce a spin flip with microwaves that are resonant
for atoms that are near maximally coupled to the cavity mode of interest, after
which, we use radiation pressure forces to remove from the cavity all the atoms
in the initial spin state. Achieving greater homogeneity in the atom-cavity
coupling will potentially enhance entanglement generation, intracavity driving
of atomic transitions, cavity-optomechanics, and quantum simulations. This
approach can easily be extended to other atomic species with microwave or
optical transitions.",2104.01201v1
2016-11-26,Specific Heat of Spin Excitations Measured by FerromagneticResonance,"Using ferromagnetic-resonance spectroscopy (FMR), we investigate the
anisotropic properties of epitaxial 3 nmPt/2 nmAg/10 nmFe/10 nmAg/GaAs(001)
films in fully saturated meta-stable states at temperatures ranging from 70 K
to 280 K. By comparison to spin-wave theory calculations, we identify the role
of thermal fluctuation of magnons in overcoming the energy barrier associated
with these meta-stable states. We show that the energy associated with the size
of the barrier that bounds the meta-stable regime is proportional to the heat
stored in the magnonic bath. Our findings offer the possibility to measure the
magnonic contribution to the heat capacity by FMR, independent of other
contributions at temperatures ranging from 0 K to ambient temperature and
above. The only requirement being that the selected sample exhibits magnetic
anisotropy, here, magnetocrystalline anisotropy.",1611.08713v2
2019-12-12,Robust spin and charge excitations throughout high-$T_c$-cuprate phase diagram from incipient Mottness,"The generic phase diagram of lightly hole-doped high-$T_c$-cuprates hosts
antiferromagnetic insulating phase with well-defined spin-wave excitations.
Contrary to the weak-coupling prediction, these modes persist up to the
overdoped metallic regime as intense and dispersive paramagnons. Here we report
on our study of the low-energy magnetic and charge excitations within the
extended Hubbard model at strong-coupling, using a modified $1/N$ expansion
method with a variational state serving as the saddle point solution. Despite
clear separation of magnetic and Hubbard-$U$ energy scales, we find that
incipient Mottness affects qualitatively dispersions and widths of magnetic
modes throughout entire phase diagram. The obtained magnetic and charge
dynamical structure factors agree semi-quantitatively with recent resonant
$X$-ray and neutron scattering data for
$\mathrm{La_{2-\mathit{x}}Sr_\mathit{x}CuO_4}$ and
$\mathrm{(Bi,Pb)_2(Sr,La)_2CuO_{6+\delta}}$ at all available doping levels. The
weak-coupling random-phase-approximation fails already for underdoped samples,
pointing to the non-trivial intertwining of distinct energy scales in cuprate
superconductors. The existence of a discrete charge mode which splits off the
electron-hole continuum is also predicted.",1912.06232v2
2019-12-31,Probing magnon-magnon coupling in exchange coupled Y$_3$Fe$_5$O$_{12}$/Permalloy bilayers with magneto-optical effects,"We demonstrate the magnetically-induced transparency (MIT) effect in
Y$_3$Fe$_5$O$_{12}$(YIG)/Permalloy(Py) coupled bilayers. The measurement is
achieved via a heterodyne detection of the coupled magnetization dynamics using
a single wavelength that probes the magneto-optical Kerr and Faraday effects of
Py and YIG, respectively. Clear features of the MIT effect are evident from the
deeply modulated ferromagnetic resonance of Py due to the
perpendicular-standing-spin-wave of YIG. We develop a phenomenological model
that nicely reproduces the experimental results including the induced amplitude
and phase evolution caused by the magnon-magnon coupling. Our work offers a new
route towards studying phase-resolved spin dynamics and hybrid magnonic
systems.",1912.13407v2
2020-10-19,Magnetic texture based magnonics,"The spontaneous magnetic orders arising in ferro-, ferri- and
antiferromagnets stem from various magnetic interactions. Depending on the
interplay and competition among the Heisenberg exchange interaction,
Dzyaloshinskii-Moriya exchange interaction, magnetic dipolar interaction and
crystal anisotropies, a great variety of magnetic textures may be stabilized,
such as magnetic domain walls, vortices, Skyrmions and spiral helical
structures. While each of these spin textures responds to external forces in a
specific manner with characteristic resonance frequencies, they also interact
with magnons, the fundamental collective excitation of the magnetic order,
which can propagate in magnetic materials free of charge transport and
therefore with low energy dissipation. Recent theories and experiments found
that the interplay between spin waves and magnetic textures is particularly
interesting and rich in physics. In this review, we introduce and discuss the
theoretical framework of magnons living on a magnetic texture background, as
well as recent experimental progress in the manipulation of magnons via
magnetic textures. The flexibility and reconfigurability of magnetic textures
are discussed regarding the potential for applications in information
processing schemes based on magnons.",2010.09180v1
2021-01-19,Gap-opening transition in Dirac semimetal ZrTe$_5$,"We apply $^{125}$Te nuclear magnetic resonance (NMR) spectroscopy to
investigate the Dirac semimetal ZrTe$_5$. With the NMR magnetic field parallel
to the $b$-axis, we observe significant quantum magnetic effects. These include
an abrupt drop at 150 K in spin-lattice relaxation rate. This corresponds to a
gap-opening transition in the Dirac carriers, likely indicating the onset of
excitonic pairing. Below 50 K, we see a more negative shift for the Te$_z$
bridging site indicating the repopulation of Dirac levels with spin polarized
carriers at these temperatures. This is the previously reported 3D quantum Hall
regime; however, we see no sign of a charge density wave as has been proposed.",2101.07387v1
2021-09-13,Trions in MoS$_2$ are quantum superpositions of intra- and intervalley spin states,"We report magneto-photoluminescence spectroscopy of gated MoS$_2$ monolayers
in high magnetic fields to 28 T. At B = 0T and electron density $n_s\sim
10^{12}cm^-2$, we observe three trion resonances that cannot be explained
within a single-particle picture. Employing ab initio calculations that take
into account three-particle correlation effects as well as local and non-local
electron-hole exchange interaction, we identify those features as quantum
superpositions of inter- and intravalley spin states. We experimentally
investigate the mixed character of the trion wave function via the filling
factor dependent valley Zeeman shift in positive and negative magnetic fields.
Our results highlight the importance of exchange interactions for exciton
physics in monolayer MoS$_2$ and provide new insights into the microscopic
understanding of trion physics in 2D multi-valley semiconductors for low excess
carrier densities.",2109.06281v1
2021-11-08,Lifting topological protection in a quantum spin Hall insulator by edge coupling,"The scientific interest in two-dimensional topological insulators (2D TIs) is
currently shifting from a more fundamental perspective to the exploration and
design of novel functionalities. Key concepts for the use of 2D TIs in
spintronics are based on the topological protection and spin-momentum locking
of their helical edge states. In this study we present experimental evidence
that topological protection can be (partially) lifted by pairwise coupling of
2D TI edges in close proximity. Using direct wave function mapping via scanning
tunneling microscopy/spectroscopy (STM/STS) we compare isolated and coupled
topological edges in the 2D TI bismuthene. The latter situation is realized by
natural lattice line defects and reveals distinct quasi-particle interference
(QPI) patterns, identified as electronic Fabry-P\'erot resonator modes. In
contrast, free edges show no sign of any single-particle backscattering. These
results pave the way for novel device concepts based on active control of
topological protection through inter-edge hybridization for, e.g., electronic
Fabry-P\'erot interferometry.",2111.04348v1
2022-10-26,Robust charge-density wave correlations in the electron-doped single-band Hubbard model,"There is growing evidence that the hole-doped single-band Hubbard and $t$-$J$
models do not have a superconducting ground state reflective of the
high-temperature cuprate superconductors but instead have striped spin- and
charge-ordered ground states. Nevertheless, it is proposed that these models
may still provide an effective low-energy model for electron-doped materials.
Here we study the finite temperature spin and charge correlations in the
electron-doped Hubbard model using quantum Monte Carlo dynamical cluster
approximation calculations and contrast their behavior with those found on the
hole-doped side of the phase diagram. We find evidence for a charge modulation
with both checkerboard and unidirectional components decoupled from any
spin-density modulations. These correlations are inconsistent with a
weak-coupling description based on Fermi surface nesting, and their doping
dependence agrees qualitatively with resonant inelastic x-ray scattering
measurements. Our results provide evidence that the single-band Hubbard model
describes the electron-doped cuprates.",2210.14930v1
2023-05-14,Adiabatic manipulation of a system interacting with a spin-bath,"Stimulated Raman Adiabatic Passage, a very efficient technique for
manipulating a quantum system based on the adiabatic theorem, is analyzed in
the case where the manipulated physical system is interacting with a spin bath.
Exploitation of the rotating wave approximation allows for the identification
of a constant of motion which simplifies both the analytical and the numerical
treatment, which allows for evaluating the total unitary evolution of system
and bath. The efficiency of the population transfer process is investigated in
several regimes, including the weak and strong coupling with the environment
and the off-resonance. The formation of appropriate Zeno subspaces explains the
lowering of the efficiency in the strong damping regime.",2305.08209v3
2023-06-26,Distorted triangular skyrmion lattice in a noncentrosymmetric tetragonal magnet,"Magnetic skyrmions are particle-like spin-swirling objects ubiquitously
realized in magnets. They are topologically stable chiral kinks composed of
multiple modulation waves of spiral spin structures, where the helicity of each
spiral is usually selected by antisymmetric exchange interactions in
noncentrosymmetric crystals. We report an experimental observation of a
distorted triangular lattice of skyrmions in the polar tetragonal magnet
EuNiGe$_3$, reflecting a strong coupling with the lattice. Moreover, through
resonant x-ray diffraction, we find that the magnetic helicity of the original
spiral at zero field is reversed when the skyrmion lattice is formed in a
magnetic field. This means that the energy gain provided by the skyrmion
lattice formation is larger than the antisymmetric exchange interaction. Our
findings will lead us to a further understanding of emergent magnetic states.",2306.14767v1
2023-06-27,Incommensurate Magnetic Order in the $\mathbb{Z}_2$ Kagome Metal GdV$_6$Sn$_6$,"We characterize the magnetic ground state of the topological kagome metal
GdV$_6$Sn$_6$ via resonant X-ray diffraction. Previous magnetoentropic studies
of GdV$_6$Sn$_6$ suggested the presence of a modulated magnetic order distinct
from the ferromagnetism that is easily polarized by the application of a
magnetic field. Diffraction data near the Gd-$L_2$ edge directly resolve a
$c$-axis modulated spin structure order on the Gd sublattice with an
incommensurate wave vector that evolves upon cooling toward a partial lock-in
transition. While equal moment (spiral) and amplitude (sine) modulated spin
states can not be unambiguously discerned from the scattering data, the overall
phenomenology suggests an amplitude modulated state with moments predominantly
oriented in the $ab$-plane. Comparisons to the ``double-flat"" spiral state
observed in Mn-based $R$Mn$_6$Sn$_6$ kagome compounds of the same structure
type are discussed.",2306.15613v1
2023-07-05,Theoretical determination of Ising-type transition by using the Self-Consistent Harmonic Approximation,"Over the years, the Self-Consistent Harmonic Approximation (SCHA) has been
successfully utilized to determine the transition temperature of many different
magnetic models, particularly the Berezinskii-Thouless-Kosterlitz transition in
two-dimensional ferromagnets. More recently, the SCHA has found application in
describing ferromagnetic samples in spintronic experiments. In such a case, the
SCHA has proven to be an efficient formalism for representing the coherent
state in the ferromagnetic resonance state. One of the main advantages of using
the SCHA is the quadratic Hamiltonian, which incorporates thermal spin
fluctuations through renormalization parameters, keeping the description simple
while providing excellent agreement with experimental data. In this article, we
investigate the SCHA application in easy-axis magnetic models, a subject that
has not been adequately explored to date. We obtain both semiclassical and
quantum approaches of the SCHA for a general anisotropic magnetic model and
employ them to determine various quantities such as the transition temperature,
spin-wave energy spectrum, magnetization, and critical exponents. To verify the
accuracy of the method, we compare the SCHA results with experimental and Monte
Carlo simulation data for many distinct well-known magnetic materials.",2307.02596v2
2023-12-27,Universal orbital and magnetic structures in infinite-layer nickelates,"We conducted a comparative study of the rare-earth infinite-layer nickelates
films, RNiO2 (R = La, Pr, and Nd) using resonant inelastic X-ray scattering
(RIXS). We found that the gross features of the orbital configurations are
essentially the same, with minor variations in the detailed hybridization. For
low-energy excitations, we unambiguously confirm the presence of damped
magnetic excitations in all three compounds. By fitting to a linear spin-wave
theory, comparable spin exchange coupling strengths and damping coefficients
are extracted, indicating a universal magnetic structure in the infinite-layer
nickelates. Interestingly, while signatures of a charge order are observed in
LaNiO2 in the quasi-elastic region of the RIXS spectrum, it is absent in NdNiO2
and PrNiO2. This prompts further investigation into the universality and the
origins of charge order within the infinite-layer inickelates.",2312.16444v1
2024-03-13,Molecular pentaquarks with hidden charm and double strangeness,"We analyze theoretically the coupled-channel meson-baryon interaction with
global flavor $\bar c c s s n$ and $\bar c c s s s$, where mesons are
pseudoscalars or vectors and baryons have $J ^P=1/2^+$ or $3/2^+$. The aim is
to explore whether the nonlinear dynamics inherent in the unitarization process
within coupled channels can dynamically generate double- and triple-strange
pentaquark-type states ($P_{css}$ and $P_{csss}$ respectively), for which there
is no experimental evidence to date. We evaluate the s-wave scattering matrix
by implementing unitarity in coupled channels, using potential kernels obtained
from t-channel vector meson exchange. The required $PPV$ and $VVV$ vertices are
obtained from Lagrangians derived through appropriate extensions of the local
hidden gauge symmetry approach to the charm sector, while capitalizing on the
symmetry of the spin and flavor wave function to evaluate the $BBV$ vertex. We
find four different poles in the double strange sector, some of them degenerate
in spin. For the triple-strange channel we find the meson-baryon interaction
insufficient to generate a bound or resonance state through the unitary
coupled-channel dynamics.",2403.08732v2
2019-09-16,"Coupled Channel Analysis of $\bar{p} p \rightarrow π^0 π^0 η$, $π^0 ηη$ and $K^+ K^- π^0$ at 900 $MeV/c$ and of $ππ$-Scattering Data","A partial wave analysis of antiproton-proton annihilation data in flight at
900 $MeV/c$ into $\pi^0 \pi^0 \eta$ , $\pi^0 \eta \eta$ and $K^+ K^- \pi^0$ is
presented. The data were taken at LEAR by the Crystal Barrel experiment in
1996. The three channels have been coupled together with $\pi\pi$-scattering
isospin I=0 S- and D-wave as well as I=1 P-wave data utilizing the K-matrix
approach. Analyticity is treated using Chew-Mandelstam functions. In the fit
all ingredients of the K-matrix, including resonance masses and widths, were
treated as free parameters. In spite of the large number of parameters, the fit
results are in the ballpark of the values published by the Particle Data Group.
In the channel $\pi^0 \pi^0 \eta$ a significant contribution of the spin exotic
$I^G=1^-$ $J^{PC}=1^{-+}$ $\pi_1$-wave with a coupling to $\pi^0 \eta$ is
observed. Furthermore the contributions of $\phi(1020) \pi^0$ and $K^*(892)^\pm
K^\mp$ in the channel $K^+ K^- \pi^0$ have been studied in detail. The
differential production cross section for the two reactions and the
spin-density-matrix elements for the $\phi(1020)$ and $K^*(892)^\pm$ have been
extracted. No spin-alignment is observed for both vector mesons. The spin
density matrix elements have been also determined for the spin exotic wave.",1909.07091v2
2013-01-11,A new type of nuclear collective motion - the spin scissors mode,"The coupled dynamics of low lying modes and various giant resonances are
studied with the help of the Wigner Function Moments method on the basis of
Time Dependent Hartree-Fock equations in the harmonic oscillator model
including spin-orbit potential plus quadrupole-quadrupole and spin-spin
residual interactions. New low lying spin dependent modes are analyzed. Special
attention is paid to the spin scissors mode.",1301.2513v1
2013-01-16,Mechanical generation of spin current by spin-rotation coupling,"Spin-rotation coupling, which is responsible for angular momentum conversion
between the electron spin and rotational deformations of elastic media, is
exploited for generating spin current. This method requires neither magnetic
moments nor spin-orbit interaction. The spin current generated in nonmagnets is
calculated in presence of surface acoustic waves. We solve the spin diffusion
equation, extended to include spin-rotation coupling, and find that larger spin
currents can be obtained in materials with longer spin lifetimes. Spin
accumulation induced on the surface is predicted to be detectable by
time-resolved Kerr spectroscopy.",1301.3596v1
2023-11-02,Unstable capillary-gravity waves,"We make rigorous spectral stability analysis for non-resonant
capillary-gravity waves as well as resonant Wilton ripples of sufficiently
small amplitude. Our analysis is based on a periodic Evans function approach,
developed recently by the authors for Stokes waves. On top of our previous
work, we add to the approach new framework ingredients, including a two-stage
Weierstrass preparation manipulation for the Periodic Evans function associated
to the wave and the definition of a stability function as an analytic function
of the wave amplitude parameter. These new ingredients are keys for proving
stability near non-resonant frequencies and defining index functions ruling
both stability and instability near non-zero resonant frequencies. We also
prove that unstable bubble spectra near non-zero resonant frequencies form, at
the leading order, either an ellipse or a circle and provide a justification
for Creedon, Deconinck, and Trichtchenko's formal asymptotic expansion for the
Floquet exponent. For non-resonant capillary-gravity waves for the stability
near the origin of the complex plane, our stability results agree with the
prediction from formal multi-scale expansion. New are our stability results
near non-zero resonant frequencies. As the effects of surface tension vanish,
our result recovers that for gravity waves. Also new are our stability results
for Wilton ripples of small amplitude near the origin as well as near non-zero
resonant frequencies.",2311.01368v2
2002-01-14,Spin polarization contrast observed in GaAs by force-detected nuclear magnetic resonance,"We applied the recently developed technique of force-detected nuclear
magnetic resonance (NMR) to observe 71Ga, 69Ga, and 75As in GaAs. The nuclear
spin-lattice relaxation time is 21$\pm$5 min for 69Ga at $\sim 5$ K and 4.6
Tesla. We have exploited this long relaxation time to first create and then
observe spatially varying nuclear spin polarization within the sample,
demonstrating a new form of contrast for magnetic resonance force microscopy
(MRFM). Such nuclear spin contrast could be used to indirectly image electron
spin polarization in GaAs-based spintronic devices.",0201216v1
2003-01-06,The Effect of Ramsauer Type Transmission Resonances on the Conductance Modulation of Spin Interferometers,"We use a mean field approach to study the conductance modulation of gate
controlled semiconductor spin interferometers based on the Rashba spin-orbit
coupling effect. The conductance modulation is found to be mostly due to
Ramsauer type transmission resonances rather than the Rashba effect in typical
structures. This is because of significant reflections at the interferometer's
contacts due to large potential barriers and effective mass mismatch between
the contact material and the semiconductor. Thus, unless particular care is
taken to eliminate these reflections, any observed conductance modulation of
spin interferometers may have its origin in the Ramsauer resonances (which is
unrelated to spin) rather than the Rashba effect.",0301052v1
2004-01-22,Spin fluctuations in the quasi-two dimensional Heisenberg ferromagnet GdI_2 studied by Electron Spin Resonance,"The spin dynamics of GdI_2 have been investigated by ESR spectroscopy. The
temperature dependences of the resonance field and ESR intensity are well
described by the model for the spin susceptibility proposed by Eremin et al.
[Phys. Rev. B 64, 064425 (2001)]. The temperature dependence of the resonance
linewidth shows a maximum similar to the electrical resistance and is discussed
in terms of scattering processes between conduction electrons and localized
spins.",0401415v1
2005-07-26,Resonant intrinsic spin Hall effect in p-type GaAs quantum well structure,"We study intrinsic spin Hall effect in p-type GaAs quantum well structure
described by Luttinger Hamiltonian and a Rashba spin-orbit coupling arising
from the structural inversion symmetry breaking. The Rashba term induces an
energy level crossing in the lowest heavy hole subband, which gives rise to a
resonant spin Hall conductance. The resonance may be used to identify the
intrinsic spin Hall effect in experiments.",0507603v1
2005-09-02,Spin-dependent resonant tunneling in ZnSe/ZnMnSe heterostructures,"Using the transfer matrix method and the effective-mass approximation, the
effect of resonant states on spin transport is studied in
ZnSe/ZnMnSe/ZnSe/ZnMnSe/ZnSe structures under the influence of both electric
and magnetic fields. The numerical results show that the ZnMnSe layers, which
act as spin filters, polarize the electric currents. Variation of thickness of
the central ZnSe layer shifts the resonant levels and exhibits an oscillatory
behavior in spin current densities. It is also shown that the spin polarization
of the tunneling current in geometrical asymmetry of the heterostructure where
two ZnMnSe layers have different Mn concentrations, depends strongly on the
thickness and the applied bias.",0509067v1
2011-09-02,Fano Mechanism of the Giant Magnetoresistance Formation in a Spin Nanostructure,"It is shown that, upon the electron quantum transport via the nanostructure
containing a spin dimer, the spin-flip processes caused by the s-f exchange
interaction between electron and dimer spins lead to the Fano resonance
effects. An applied magnetic field eliminates degeneracy of the upper triplet
states of the dimer, changes the conditions for implementation of the Fano
resonances and antiresonances, and induces the new Fano resonance and
antiresonance. It results in the occurrence of a sharp peak and dip in the
energy dependence of transmittance. These effects strongly modify the
current--voltage characteristic of the spin-dimer structure in a magnetic field
and form giant magnetoresistance.",1109.0391v1
2011-11-14,Electron spin resonance study of anisotropic interactions in a two-dimensional spin gap magnet PHCC,"Fine details of the excitation spectrum of the two-dimensional spin-gap
magnet PHCC are revealed by electron spin resonance investigations. The values
of anisotropy parameters and the orientations of the anisotropy axes are
determined by accurate measurements of the angular, frequency-field and
temperature dependences of the resonance absorption. The properties of a
spin-gap magnet in the vicinity of critical field are discussed in terms of
sublevel splittings and g-factor anisotropy.",1111.3223v1
2012-01-05,Heavy quark spin symmetry breaking in near-threshold $J^{PC}=1^{--}$ quarkonium-like resonances,"A mixing of near-threshold quarkonium-like resonances with heavy
meson-antimeson pairs results in an enhancement of heavy quark spin symmetry
breaking, since the meson pairs are not eigenstates of the heavy quark spin.
The decomposition of $P$-wave states of meson pairs in terms of the
heavy-quark-pair spin states is considered in the channel with $J^{PC}=1^{--}$,
which is directly produced in $e^+e^-$ annihilation. Specific processes are
suggested for experimental study of the effects of the mixing with heavy meson
pairs and of the internal spin structure of bottomonium and charmonium
resonances.",1201.1222v1
2015-03-27,Spin superradiance by magnetic nanomolecules and nanoclusters,"Spin dynamics of assemblies of magnetic nanomolecules and nanoclusters can be
made coherent by inserting the sample into a coil of a resonant electric
circuit. Coherence is organized through the arising feedback magnetic field of
the coil. The coupling of a magnetic sample with a resonant circuit induces
fast spin relaxation and coherent spin radiation, that is, superradiance. We
consider spin dynamics described by a realistic Hamiltonian, typical of
magnetic nanomolecules and nanoclusters. The role of magnetic anisotropy is
studied. A special attention is paid to geometric effects related to the mutual
orientation of the magnetic sample and resonator coil.",1503.08036v1
2020-09-29,The role of spin-flip assisted or orbital mixing tunneling on transport through strongly correlated multilevel quantum dot,"Using the slave boson Kotliar-Ruckenstein approach (SBMFA) for N level
Anderson model, we compare fully symmetric SU(N) Kondo resonances occurring for
spin and orbital conserving tunneling with many-body resonances for the dot
with broken symmetry caused by spin, orbital or full spin-orbital mixing. As a
result of interorbital or spin flip processes new interference paths emerge,
which manifests in the occurrence of antibonding Dicke like and bonding Kondo
like resonances. The analytical expressions for linear conductances and linear
temperature thermopower coefficient for arbitrary N are found.",2009.14122v1
2021-06-28,Magnetic Resonance Force Microscopy with Overlapping Frequencies of Cantilever and Spin,"We have studied theoretically magnetic resonance force microscopy (MRFM) with
a high frequency nanomechanical cantilever when the cantilever frequency
matches the resonant frequency of a single electron spin. Our estimations show
that in this scenario the relative frequency shift of the cantilever can be
much greater than the record MRFM frequency shift achieved in experiments with
a single spin detection. Experimental realization of our proposal could open
the way for fast detection of a single electron spin and even for detection of
a single nuclear spin.",2106.15032v1
2022-06-01,Electrically driven spin resonance with bichromatic driving,"Electrically driven spin resonance (EDSR) is an established tool for
controlling semiconductor spin qubits. Here, we theoretically study a
frequency-mixing variant of EDSR, where two driving tones with different drive
frequencies are applied, and the resonance condition connects the spin Larmor
frequency with the sum of the two drive frequencies. Focusing on flopping-mode
operation, we calculate the parameter dependence of the Rabi frequency and the
Bloch-Siegert shift. A shared-control spin qubit architecture could benefit
from this bichromatic EDSR scheme, as it enables simultaneous single-qubit
gates.",2206.00399v2
2023-09-20,Scaling of self-stimulated spin echoes,"Self-stimulated echoes have recently been reported in the high cooperativity
and inhomogeneous coupling regime of spin ensembles with superconducting
resonators. In this work, we study their relative amplitudes using
echo-silencing made possible by a fast frequency tunable resonator. The highly
anisotropic spin linewidth of Er$^{3+}$ electron spins in the CaWO$_4$ crystal
also allows to study the dependence on spin-resonator ensemble cooperativity.
It is demonstrated that self-stimulated echoes primarily result from a
combination of two large control pulses and the echo preceding it.",2309.11169v1
2003-04-19,Spin-Wave Theory for s=1 Antiferromagnetic Isotropic Chain,"In the paper we describe the modification of spin-wave theory for
one-dimensional isotropic antiferromagnet. This theory enables to obtain the
energy of magnetic excitations of short wave length and correlation function in
agreement with numerical studies.",0304444v1
1999-06-04,Explicit expressions of spin wave functions,"We derive the explicit expressions of the canonical and helicity wave
functions for massive particles with arbitrary spins. Properties of these wave
functions are discussed.",9906250v1
2013-05-15,Multi-resonance orbital model of high-frequency quasi-periodic oscillations: possible high-precision determination of black hole and neutron star spin,"Using known frequencies of the twin-peak high-frequency quasiperiodic
oscillations (HF QPOs) and known mass of the central black hole, the black-hole
dimensionless spin can be determined by assuming a concrete version of the
resonance model. However, a wide range of observationally limited values of the
black hole mass implies low precision of the spin estimates. We discuss the
possibility of higher precision of the black hole spin measurements in the
framework of a multi-resonance model inspired by observations of more than two
HF QPOs in the black hole systems, which are expected to occur at two (or more)
different radii of the accretion disc. For the black hole systems we focus on
the special case of duplex frequencies, when the top, bottom, or mixed
frequency is common at two different radii where the resonances occur giving
triple frequency sets. The sets of triple frequency ratios and the related spin
are given. The strong resonance model for ""magic"" values of the black hole spin
means that two (or more) versions of resonance could occur at the same radius,
allowing cooperative effects between the resonances. For neutron star systems
we introduce a resonant switch model that assumes switching of oscillatory
modes at resonant points. In the case of doubled twin-peak HF QPOs excited at
two different radii with common top, bottom, or mixed frequency, the black hole
spin is given by the triple frequency ratio set. The spin is determined
precisely, but not uniquely, because the same frequency set could correspond to
more than one concrete spin. The black hole mass is given by the magnitude of
the observed frequencies. The resonant switch model puts relevant limits on the
mass and spin of neutron stars, and we expect a strong increase in the fitting
procedure precision when different twin oscillatory modes are applied to data
in the vicinity of different resonant points.",1305.3552v1
1997-11-23,Origin of Pure Spin Superradiance,"The question addressed in this paper is: What originates pure spin
superradiance in a polarized spin system placed inside a resonator? The term
""pure"" means that no initial coherence is imposed on spins, and its appearance
manifests a purely self-organized collective effect. The consideration is based
on a microscopic model with dipole spin interactions. An accurate solution of
evolution equations is given. The results show that the resonator Nyquist noise
does not play, contrary to the common belief, any role in starting spin
superradiance, but the emergence of the latter is initiated by local spin
fluctuations. The decisive role of nonsecular dipole interactions is stressed.",9711237v1
2002-05-02,Spin battery operated by ferromagnetic resonance,"Precessing ferromagnets are predicted to inject a spin current into adjacent
conductors via Ohmic contacts, irrespective of a conductance mismatch with, for
example, doped semiconductors. This opens the way to create a pure spin source
spin battery by the ferromagnetic resonance. We estimate the spin current and
spin bias for different material combinations.",0205028v2
2005-03-29,Spin-Forster transfer in optically excited quantum dots,"The mechanisms of energy and spin transfer in quantum dot pairs coupled via
the Coulomb interaction are studied. Exciton transfer can be resonant or
phonon-assisted. In both cases, the transfer rates strongly depend on the
resonance conditions. The spin selection rules in the transfer process come
from the exchange and spin-orbit interactions. The character of energy
dissipation in spin transfer is different than that in the traditional spin
currents. The spin-dependent photon cross-correlation functions reflect the
exciton transfer process. In addition, a mathematical method to calculate
F\""orster transfer in crystalline nanostructures beyond the dipole-dipole
approximation is described.",0503688v1
2010-09-28,Spin-orbit anisotropy measured using ballistic spin resonance,"Spin relaxation can be greatly enhanced in narrow channels of two-dimensional
electron gas due to ballistic spin resonance, which is mediated by spin-orbit
interaction for trajectories that bounce rapidly between channel walls. The
channel orientation determines which momenta affect the relaxation process, so
comparing relaxation for two orientations provides a direct determination of
spin-orbit anisotropy. Electrical measurements of pure spin currents are shown
to reveal an order of magnitude stronger relaxation for channels fabricated
along the [110] crystal axis in a GaAs electron gas compared to [-110]
channels, believed to result from interference between structural and bulk
inversion asymmetries.",1009.5702v1
2012-08-20,Spin current rectification from a spin-biased quantum dot,"We compute the spin current rectification coefficient of a non-equilibrium
quantum dot subject to a spin bias and an {\it ac} charge bias with small
amplitude. As a function of the position of the resonant level the spin current
rectification coefficient shows a set of three peaks around the gate voltage at
which the resonant or the upper level of the dot is in the vicinity of the
equilibrium Fermi level in the leads. The peak heights can be related to the
average number of the quantum dot electrons. We discuss the frequency
dependence of the spin current rectification coefficient as well and emphasize
the effects of the photon-assisted spin transport through the dot.",1208.3974v1
2019-10-09,Transverse spin dynamics of light: the generalized spin-momentum locking for structured guided modes,"Quantum spin-Hall effect, a manifestation of topological properties that
govern the behavior of surface states, was studied intensively in condensed
matter physics resulting in the discovery of topological insulators. The
quantum spin-Hall effect of light was introduced for surface plane-waves which
intrinsically carry transverse optical spin, leading to many intriguing
phenomena and applications in unidirectional waveguiding, metrology and quantum
technologies. In addition to spin, optical waves can exhibit complex
topological properties of vectorial electromagnetic fields, associated with
orbital angular momentum or nonuniform intensity variations. Here, by
considering both spin and angular momentum, we demonstrate a generalized
spin-momentum relationship that governs vectorial properties of guided
electromagnetic waves, extending optical quantum spin-Hall effect to a
two-dimensional vector field of structured guided wave. The effect results in
the appearance of the out-of-plane transverse optical spins, which vary
progressively from the 'up' state to the 'down' state around the energy flow,
and their variation is uniquely locked to the energy propagation direction. The
related spin-momentum locking in a chiral spin swirl is demonstrated with four
kinds of surface structured waves and proven both theoretically and
experimentally. The results provide understanding of the spin dynamics in
electromagnetic guided waves and show great importance in spin optics,
topological photonics and optical spin-based devices and techniques.",1910.03904v2
2017-02-06,Loschmidt echo in many-spin systems: a quest for intrinsic decoherence and emergent irreversibility,"If a magnetic polarization excess is locally injected in a crystal of
interacting spins, this ""excitation"" would spread as consequence of spin-spin
interactions. Such an apparently irreversible process is known as spin
diffusion and it can lead the system back to ""equilibrium"". Even so, a unitary
quantum dynamics would ensure a precise memory of the non-equilibrium initial
condition. Then, if at certain time, say $t/2$, an experimental protocol
reverses the many-body dynamics, it would drive the system back to the initial
non-equilibrium state at time $t$. As a matter of fact, the reversal is always
perturbed by small experimental imperfections and/or uncontrolled internal or
environmental degrees of freedom. This limits the amount of signal $M(t)$
recovered locally at time $t$. The degradation of $M(t)$ accounts for these
perturbations, which can also be seen as the sources of decoherence. This idea
defines the Loschmidt echo (LE), which embodies the various time-reversal
procedures implemented in nuclear magnetic resonance. Here, we present an
invitation to the study of the LE following the pathway induced by the
experiments. With such a purpose, we provide a historical and conceptual
overview that briefly revisits selected phenomena that underlie the LE
dynamics, ultimately leading to the discussion of irreversibility as an
emergent phenomenon. In addition, we introduce the LE formalism by means of
spin-spin correlation functions and we present new results that could trigger
new experiments and theoretical ideas. In particular, we propose to transform
an initially localized excitation into a more complex initial state, enabling a
dynamically prepared LE. This induces a global definition of the LE in terms of
the raw overlap between many-body wave functions. Our results show that as the
complexity of the prepared state increases, it becomes more fragile towards
small perturbations.",1702.01475v1
2023-10-31,Coherent manipulation of nuclear spins in the strong driving regime,"Spin-based quantum information processing makes extensive use of spin-state
manipulation. This ranges from dynamical decoupling of nuclear spins in quantum
sensing experiments to applying logical gates on qubits in a quantum processor.
Here we present an antenna for strong driving in quantum sensing experiments
and theoretically address challenges of the strong driving regime. First, we
designed and implemented a micron-scale planar spiral RF antenna capable of
delivering intense fields to a sample. The planar antenna is tailored for
quantum sensing experiments using the diamond's nitrogen-vacancy (NV) center
and should be applicable to other solid-state defects. The antenna has a broad
bandwidth of 22 MHz, is compatible with scanning probes, and is suitable for
cryogenic and ultrahigh vacuum conditions. We measure the magnetic field
induced by the antenna and estimate a field-to-current ratio of $113\pm 16$
G/A, representing a x6 increase in efficiency compared to the state-of-the-art.
We demonstrate the antenna by driving Rabi oscillations in $^1$H spins of an
organic sample on the diamond surface and measure $^1$H Rabi frequencies of
over 500 kHz, i.e., $\mathrm{\pi}$-pulses shorter than 1 $\mu s$ - faster than
previously reported in NV-based nuclear magnetic resonance (NMR). Finally, we
discuss the implications of driving spins with a field tilted from the
transverse plane in a regime where the driving amplitude is comparable to the
spin-state splitting, such that the rotating wave approximation does not
describe the dynamics well. We present a recipe to optimize pulse fidelity in
this regime based on a phase and offset-shifted sine drive, that may be
optimized without numerical optimization procedures or precise modeling of the
experiment. We consider this approach in a range of driving amplitudes and show
that it is particularly efficient in the case of a tilted driving field.",2310.20667v1
2021-09-13,One-dimensional force-free numerical simulations of Alfven waves around a spinning black string,"We performed one-dimensional force-free magnetodynamic numerical simulations
of the propagation of Alfven waves along magnetic field lines around a spinning
black-hole-like object, the Banados--Teitelboim--Zanelli black string, to
investigate the dynamic process of wave propagation and energy transport with
Alfven waves. We considered axisymmetric and stationary magnetosphere and
perturbed the background magnetosphere to obtain the linear wave equation for
the Alfven wave mode. The numerical results show that the energy of Alfven
waves monotonically increases as the waves propagate outwardly along the
rotating curved magnetic field line around the ergosphere, where energy seems
not to be conserved, in the case of energy extraction from the black string by
the Blandford--Znajek mechanism. The apparent breakdown of energy conservation
suggests the existence of an additional wave induced by the Alfven wave.
Considering the additional fast magnetosonic wave induced by the Alfven wave,
the energy conservation is recovered. Similar relativistic phenomena, such as
the amplification of Alfven waves and induction of fast magnetosonic waves, are
expected around a spinning black hole.",2109.05703v1
2004-11-09,Chiral spin resonance and spin-Hall conductivity in the presence of the electron-electron interactions,"We discuss the electron spin resonance in two-dimensional electron gas at
zero external magnetic field. This spin-resonance is due to the transitions
between the electron states, which are split by the spin-orbit (SO)
interaction, and is termed as the chiral spin resonance (CSR). It can be
excited by the in-plane component of the electric field of microwave radiation.
We show that there exists an inherent relationship between the spin-Hall
conductivity and the CSR in a system with the SO interaction. Since in the
presence of the SO interaction spin is not conserved, the electron-electron
interaction renormalizes the spin-Hall conductivity as well as the frequency of
the CSR. The effects of the electron interaction in systems with the SO
interaction are analyzed both phenomenologically and microscopically.",0411239v3
2010-04-06,Numerical study of resonant spin relaxation in quasi-1D channels,"Recent experiments demonstrate that a ballistic version of spin resonance,
mediated by spin-orbit interaction, can be induced in narrow channels of a
high-mobility GaAs two-dimensional electron gas by matching the spin precession
frequency with the frequency of bouncing trajectories in the channel. Contrary
to the typical suppression of Dyakonov-Perel' spin relaxation in confined
geometries, the spin relaxation rate increases by orders of magnitude on
resonance. Here, we present Monte Carlo simulations of this effect to explore
the roles of varying degrees of disorder and strength of spin-orbit
interaction. These simulations help to extract quantitative spin-orbit
parameters from experimental measurements of ballistic spin resonance, and may
guide the development of future spintronic devices.",1004.0768v1
2010-05-04,A double scale fast algorithm for the transient evolution of a resonant tunneling diode,"The simulation of the time-dependent evolution of the resonant tunneling
diode is done by a multiscale algorithm exploiting the existence of resonant
states. After revisiting and improving the algorithm developed in [N. Ben
Abdallah, O. Pinaud, J. Comp. Phys. 213 (2006) 288-310] for the stationary
case, the time-dependent problem is dealt with. The wave function is decomposed
into a non resonant part and a resonant one. The projection method to compute
the resonant part leads to an accurate algorithm thanks to a suitable
interpolation of the non resonant one. The simulation times are largely
reduced.",1005.0444v2
2015-03-31,Local resonance and Bragg bandgaps in sandwich beams containing periodically inserted resonators,"We study the low frequency wave propagation behavior of sandwich beams
containing periodically embedded internal resonators. A closed form expression
for the propagation constant is obtained using a phased array approach and
verified using finite element simulations. We show that local resonance and
Bragg bandgaps coexist in such a system and that the width of both bandgaps is
a function of resonator parameters as well as their periodicity. The
interaction between the two bandgaps is studied by varying the local resonance
frequency. We find that a single combined bandgap does not exist for this
system and that the Bragg bandgaps transition into sub-wavelength bandgaps when
the local resonance frequency is above their associated classical Bragg
frequency.",1503.09048v1
2015-12-08,Effects of pairing correlation on low-lying quasi-particle resonance in neutron drip-line nuclei,"We discuss effects of pairing correlation on quasi-particle resonance. We
analyze in detail how the width of low-lying quasi-particle resonance is
governed by the pairing correlation in the neutron drip-line nuclei. We
consider the 46Si + n system to discuss low-lying p wave quasi-particle
resonance. Solving the Hartree-Fock-Bogoliubov equation in the coordinate space
with scattering boundary condition, we calculate the phase shift, the elastic
cross section, the resonance width and the resonance energy. We found that the
pairing correlation has an effect to reduce the width of quasi-particle
resonance which originates from a particle-like orbit in weakly bound nuclei.",1512.02675v1
2017-01-30,Extracting losses from asymmetric resonances in micro-ring resonators,"Propagation losses in micro-ring resonator waveguides can be determined from
the shape of individual resonances in their transmission spectrum. The losses
are typically extracted by fitting these resonances to an idealized model that
is derived using scattering theory. Reflections caused by waveguide boundaries
or stitching errors, however, cause the resonances to become asymmetric,
resulting in poor fits and unreliable propagation loss coefficients. We derive
a model that takes reflections into account and, by performing full-wave
simulations, we show that this model accurately describes the asymmetric
resonances that result from purely linear effects, yielding accurate
propagation loss coefficients.",1701.08464v2
2016-03-31,Resonant terms on gyrocenter coordinates introduced by resonant electromagnetic perturbations,"It's pointed out that the treatment of the resonant electromagnetic
perturbation with the Lie transform method adopted in the gyrokinetic theory
generates some nonphysical terms in the trajectory equations. By utilizing a
modified application of this transform method, the resonant terms in the
trajectory equations satisfying each resonant condition are found out up to the
second harmonic resonance. Through separating the fast-dynamic terms from the
slow-dynamic ones, the slow-dynamic trajectory equations including the resonant
terms are derived for various resonant conditions. The slow-dynamic evolution
equation of gyroangle reveals that the real gyrating frequency of the charged
particle around the magnetic field line under driving by the resonant wave has
a shift from the cyclotron frequency without the wave driving. To study the
effect caused by the frequency shift, a simple example for the
fundamental-frequency cyclotron resonance is presented.",1603.09632v5
2012-12-21,Shot noise of spin current and spin transfer torque,"We report the theoretical investigation of noise spectrum of spin current and
spin transfer torque for non-colinear spin polarized transport in a spin-valve
device which consists of normal scattering region connected by two
ferromagnetic electrodes. Our theory was developed using non-equilibrium
Green's function method and general non-linear $S^\sigma-V$ and $S^\tau-V$
relations were derived as a function of angle $\theta$ between magnetization of
two leads. We have applied our theory to a quantum dot system with a resonant
level coupled with two ferromagnetic electrodes. It was found that for the MNM
system, the auto-correlation of spin current is enough to characterize the
fluctuation of spin current. For a system with three ferromagnetic layers,
however, both auto-correlation and cross-correlation of spin current are needed
to characterize the noise spectrum of spin current. Furthermore, the spin
transfer torque and the torque noise were studied for the MNM system. For a
quantum dot with a resonant level, the derivative of spin torque with respect
to bias voltage is proportional to $\sin\theta$ when the system is far away
from the resonance. When the system is near the resonance, the spin transfer
torque becomes non-sinusoidal function of $\theta$. The derivative of noise
spectrum of spin transfer torque with respect to the bias voltage $N_\tau$
behaves differently when the system is near or far away from the resonance.
Specifically, the differential shot noise of spin transfer torque $N_\tau$ is a
concave function of $\theta$ near the resonance while it becomes convex
function of $\theta$ far away from resonance. For certain bias voltages, the
period $N_\tau(\theta)$ becomes $\pi$ instead of $2\pi$. For small $\theta$, it
was found that the differential shot noise of spin transfer torque is very
sensitive to the bias voltage and the other system parameters.",1212.5474v1
1997-02-07,Cylindrical versus Spherical Resonant Antennas for Gravitational Wave Detection,"The principles and detection of gravitational waves by resonant antennas are
briefly discussed. But the main purpose of this short note is to compare the
two geometries of resonant antennas, the well-known cylindrical to the
spherical type. Some features of a two sphere observatory are also discussed.",9702016v1
2004-10-18,Resonant pumping in nonlinear Klein-Gordon equation and solitary packets of waves,"Solution of the nonlinear Klein-Gordon equation perturbed by small external
force is investigated. The frequency of perturbation varies slowly and passes
through a resonance. The resonance generates a solitary packets of waves. Full
asymptotic description of this process is presented.",0410041v1
2005-03-09,The slowly passage through the resonances and wave packets with the different carriers,"Solution of the nonlinear Klein-Gordon equation perturbed by small external
force is investigated. The perturbation is represented by finite collections of
harmonics. The frequencies of the perturbation vary slowly and pass through the
resonant values consecutively. The resonances lead to the sequence of the wave
packets with the different fast oscillated carriers. Full asymptotic
description of this process is presented.",0503019v1
2013-10-14,"Bilinear dispersive estimates via space-time resonances, part II: dimensions 2 and 3","Consider a bilinear interaction between two linear dispersive waves with a
generic resonant structure (roughly speaking, space and time resonant sets
intersect transversally). We derive an asymptotic equivalent of the solution
for data in the Schwartz class, and bilinear dispersive estimates for data in
weighted Lebesgue spaces. An application to water waves with infinite depth,
gravity and surface tension is also presented.",1310.3659v1
2013-12-02,Coherent excitation-selective spectroscopy in planar metamaterials,"In a proof-of-principle experiment with metamaterials exhibiting electric
dipolar and magnetic dipolar resonances, we demonstrated that the electric and
magnetic resonances can be separately switches off and on by positioning the
metamaterials along a standing wave, while both resonances are present in
travelling-wave spectra.",1312.0524v1
2015-07-07,Long-time existence and resonant approximation for the quadratic nonlinear wave equation with an anisotropic harmonic trapping,"We establish long-time existence and uniqueness for the 2D wave equation with
a harmonic potential in one direction. This proof relies on a fine study of the
so-called space-time resonances of the equation. Then we derive a resonant
system for this equation and we prove that it is a satisfying approximation for
the original equation.",1507.01683v1
2007-05-25,Interplay of the Rashba and Dresselhaus spin-orbit coupling in the optical spin susceptibility of 2D electron systems,"We present calculations of the frequency-dependent spin susceptibility tensor
of a two-dimensional electron gas with competing Rashba and Dresselhaus
spin-orbit interaction. It is shown that the interplay between both types of
spin-orbit coupling gives rise to an anisotropic spectral behavior of the spin
density response function which is significantly different from that of
vanishing Rashba or Dresselhaus case. Strong resonances are developed in the
spin susceptibility as a consequence of the angular anisotropy of the energy
spin-splitting. This characteristic optical modulable response may be useful to
experimentally probe spin accumulation and spin density currents in such
systems.",0705.3849v1
2011-03-11,Spin Transport in Polaronic and Superfluid Fermi Gases,"We present measurements of spin transport in ultracold gases of fermionic
lithium-6 in a mixture of two spin states at a Feshbach resonance. In
particular, we study the spin dipole mode, where the two spin components are
displaced from each other against a harmonic restoring force. We prepare a
highly-imbalanced, or polaronic, spin mixture with a spin dipole excitation and
observe strong, unitarity limited damping of the spin dipole mode. In gases
with small spin imbalance, below the Pauli limit for superfluidity, we observe
strongly damped spin flow despite the presence of a superfluid core.",1103.2337v1
2015-06-07,Spin current evolution in the separated spin-up and spin-down quantum hydrodynamics,"We have developed the quantum hydrodynamic model that describes particles
with spin-up and with spin-down in separate. We have derived the equation of
the spin current evolution as a part of the set of the quantum hydrodynamics
(QHD) equations that treat particles with different projection of spin on the
preferable direction as two different species. We have studied orthogonal
propagation of waves in the external magnetic field and determined the
contribution of quantum corrections due to the Bohm potential and to
magnetization energy of particles with different projections of spin in the
spin current wave dispersion. We have analyzed the limits of weak and strong
magnetic fields.",1506.02259v1
2010-06-18,Discrete and mesoscopic regimes of finite-size wave turbulence,"Bounding volume results in discreteness of eigenmodes in wave systems. This
leads to a depletion or complete loss of wave resonances (three-wave,
four-wave, etc.), which has a strong effect on Wave Turbulence, (WT) i.e. on
the statistical behavior of broadband sets of weakly nonlinear waves. This
paper describes three different regimes of WT realizable for different levels
of the wave excitations: Discrete, mesoscopic and kinetic WT. Discrete WT
comprises chaotic dynamics of interacting wave ""clusters"" consisting of
discrete (often finite) number of connected resonant wave triads (or quarters).
Kinetic WT refers to the infinite-box theory, described by well-known
wave-kinetic equations. Mesoscopic WT is a regime in which either the discrete
and the kinetic evolutions alternate, or when none of these two types is purely
realized. We argue that in mesoscopic systems the wave spectrum experiences a
sandpile behavior. Importantly, the mesoscopic regime is realized for a broad
range of wave amplitudes which typically spans over several orders on
magnitude, and not just for a particular intermediate level.",1006.3631v1
2016-04-01,"Wide-band, nanoscale magnetic resonance spectroscopy using quantum relaxation of a single spin in diamond","We demonstrate a wide-band all-optical method of nanoscale magnetic resonance
(MR) spectroscopy under ambient conditions. Our method relies on
cross-relaxation between a probe spin, the electronic spin of a
nitrogen-vacancy centre in diamond, and target spins as the two systems are
tuned into resonance. By optically monitoring the spin relaxation time ($T_1$)
of the probe spin while varying the amplitude of an applied static magnetic
field, a frequency spectrum of the target spin resonances, a $T_1$-MR spectrum,
is obtained. As a proof of concept, we measure $T_1$-MR spectra of a small
ensemble of $^{14}$N impurities surrounding the probe spin within the diamond,
with each impurity comprising an electron spin 1/2 and a nuclear spin 1. The
intrinsically large bandwidth of the technique and probe properties allows us
to detect both electron spin transitions -- in the GHz range -- and nuclear
spin transitions -- in the MHz range -- of the $^{14}$N spin targets. The
measured frequencies are found to be in excellent agreement with theoretical
expectations, and allow us to infer the hyperfine, quadrupole and gyromagnetic
constants of the target spins. Analysis of the strength of the resonances
obtained in the $T_1$-MR spectrum reveals that the electron spin transitions
are probed via dipole interactions, while the nuclear spin resonances are
dramatically enhanced by hyperfine coupling and an electron-mediated process.
Finally, we investigate theoretically the possibility of performing $T_1$-MR
spectroscopy on nuclear spins without hyperfine interaction and predict
single-proton sensitivity using current technology. This work establishes
$T_1$-MR as a simple yet powerful technique for nanoscale MR spectroscopy, with
broadband capability and a projected sensitivity down to the single nuclear
spin level.",1604.00160v1
2001-01-30,Effect of nearest- and next-nearest neighbor interactions on the spin-wave velocity of one-dimensional quarter-filled spin-density-wave conductors,"We study spin fluctuations in quarter-filled one-dimensional
spin-density-wave systems in presence of short-range Coulomb interactions. By
applying a path integral method, the spin-wave velocity is calculated as a
function of on-site (U), nearest (V) and next-nearest (V_2) neighbor-site
interactions. With increasing V or V_2, the pure spin-density-wave state
evolves into a state with coexisting spin- and charge-density waves. The
spin-wave velocity is reduced when several density waves coexist in the ground
state, and may even vanish at large V. The effect of dimerization along the
chain is also considered.",0101450v2
2010-08-31,Dynamics of the collective modes of an inhomogeneous spin ensemble in a cavity,"We study the excitation dynamics of an inhomogeneously broadened spin
ensemble coupled to a single cavity mode. The collective excitations of the
spin ensemble can be described in terms of generalized spin waves and, in the
absence of the cavity, the free evolution of the spin ensemble can be described
as a drift in the wave number without dispersion. In this article we show that
the dynamics in the presence of coupling to the cavity mode can be described
solely by a modified time evolution of the wave numbers. In particular, we show
that collective excitations with a well- defined wave number pass without
dispersion from negative to positive valued wave numbers without populating the
zero wave number spin wave mode. The results are relevant for multi-mode
collective quantum memories where qubits are encoded in different spin waves.",1008.5197v2
2017-11-01,Adiabatic Control of Spin-Wave Propagation using Magnetisation Gradients,"Spin waves are of large interest as data carriers for future logic devices.
However, due to the strong anisotropic dispersion relation of dipolar
spin-waves in in-plane magnetised films the realisation of two-dimensional
information transport remains a challenge. Bending of the energy flow is
prohibited since energy and momentum of spin waves cannot be conserved while
changing the direction of wave propagation. Thus, non-linear or non-stationary
mechanisms are usually employed. Here, we propose to use reconfigurable
laser-induced magnetisation gradients to break the system's translational
symmetry. The resulting changes in the magnetisation shift the dispersion
relations locally and allow for operating with different spin-wave modes at the
same frequency. Spin-wave momentum is first transformed via refraction at the
edge of the magnetisation gradient region and then adiabatically modified
inside it. Along these lines the spin-wave propagation direction can be
controlled in a broad frequency range with high efficiency.",1711.00508v1
2016-11-23,Creation of uni-directional spin-wave emitters by utilizing interfacial Dzyaloshinskii-Moriya interaction,"We present an analytic and numerical study of the creation of an
uni-directional spin-wave emission in ultra-thin ferromagnetic films sandwiched
in an asymmetric layer stack. For this we extend the analytical description of
spin waves in spin-wave waveguides by the incorporation of the influence of the
interfacial Dzyaloshinskii-Moriya interaction on the spin-wave propagation. By
exploring the model system Ni$_{81}$Fe$_{19}$/Pt we show that it is possible to
achieve an uni-directional spin-wave emission by combining wave-vector
selective excitation sources with the frequency splitting which arises from
interfacial Dzyaloshinskii-Moriya interaction. Hereby we focus on device
feature sizes and spin-wave wavelengths compatible with state-of-the art
excitation and detection schemes. We demonstrate that the optimum operation
conditions for the non-reciprocal emission can be predicted using the presented
analytical formalism",1611.07841v2
2022-07-03,Deeply nonlinear excitation of self-normalised exchange spin waves,"Spin waves are ideal candidates for wave-based computing, but the
construction of magnetic circuits is blocked by a lack of an efficient
mechanism to excite long-running exchange spin waves with normalised
amplitudes. Here, we solve the challenge by exploiting the deeply nonlinear
phenomena of forward-volume spin waves in 200 nm wide nanoscale waveguides and
validate our concept with microfocused Brillouin light scattering spectroscopy.
An unprecedented nonlinear frequency shift of >2 GHz is achieved, corresponding
to a magnetisation precession angle of 55{\deg} and enabling the excitation of
exchange spin waves with a wavelength of down to ten nanometres with an
efficiency of >80%. The amplitude of the excited spin waves is constant and
independent of the input microwave power due to the self-locking nonlinear
shift, enabling robust adjustment of the spin wave amplitudes in future on-chip
magnonic integrated circuits.",2207.01121v1
2019-12-19,Spin rotation by resonant electric field in few-level quantum dots: Floquet dynamics and tunneling,"We study electric dipole spin resonance caused by sub-terahertz (THz)
radiation in a multilevel finite-size quantum dot formed in a nanowire focusing
on the range of driving electric fields amplitudes where a strong interplay
between the Rabi spin oscillations and tunneling from the dot to continuum
states can occur. A strong effect of the tunneling on the spin evolution in
this regime occurs due to formation of mixed spin states. As a result, the
tunneling strongly limits possible spin manipulations time. We demonstrate a
backaction of the spin dynamics on the tunneling and position of the electron.
The analysis of the efficiency of the spin manipulation in terms of the system
energy shows that tunneling decreases this efficiency. Fourier spectra of the
time-dependent expectation value of the electron position show a strong effect
of the spin-orbit coupling on their low-frequency components. This results can
be applied to operational properties of spin-based nanodevices and extending
the range of possible spin resonance frequencies to the THz domain.",1912.09054v2
2021-05-28,Stimulated resonant spin amplification reveals millisecond electron spin coherence time of rare-earth ions in solids,"The inhomogeneity of an electron spin ensemble as well as fluctuating
environment acting upon individual spins drastically shorten the spin coherence
time $T_2$ and hinder coherent spin manipulation. We show that this problem can
be solved by the simultaneous application of a radiofrequency (rf) field, which
stimulates coherent spin precession decoupled from an inhomogeneous
environment, and periodic optical pulses, which amplify this precession. The
resulting resonance, taking place when the rf field frequency approaches the
laser pulse repetition frequency, has a width determined by the spin coherence
time $T_2$ that is free from the inhomogeneity effects. We measure a
50-Hz-narrow electron spin resonance and milliseconds-long $T_2$ for electrons
in the ground state of Ce$^{3+}$ ions in the YAG lattice at low temperatures,
while the inhomogeneous spin dephasing time $T_2^*$ is only 25 ns. This study
paves the way to coherent optical manipulation in spin systems decoupled from
their inhomogeneous environment.",2105.13674v2
2023-01-24,Longitudinal coupling between electrically driven spin-qubits and a resonator,"At the core of the semiconducting spin qubits success is the ability to
manipulate them electrically, enabled by the spin-orbit interactions. However,
most implementations require external magnetic fields to define the spin qubit,
which in turn activate various charge noise mechanisms. Here we study spin
qubits confined in quantum dots at zero magnetic fields, that are driven
periodically by electrical fields and are coupled to a microwave resonator.
Using Floquet theory, we identify a well-defined Floquet spin-qubit originating
from the lowest degenerate spin states in the absence of driving. We find both
transverse and longitudinal couplings between the Floquet spin qubit and the
resonator, which can be selectively activated by modifying the driving
frequency. We show how these couplings can facilitate fast qubit readout and
the implementation of a two-qubit CPHASE gate. Finally, we use adiabatic
perturbation theory to demonstrate that the spin-photon couplings originate
from the non-Abelian geometry of states endowed by the spin-orbit interactions,
rendering these findings general and applicable to a wide range of solid-state
spin qubits.",2301.10163v1
2012-03-11,Roles of Fast-Cyclotron and Alfven-Cyclotron Waves for the Multi-Ion Solar Wind,"Using linear Vlasov theory of plasma waves and quasi-linear theory of
resonant wave-particle interaction, the dispersion relations and the
electromagnetic field fluctuations of fast and Alfven waves are studied for a
low-beta multi-ion plasma in the inner corona. Their probable roles in heating
and accelerating the solar wind via Landau and cyclotron resonances are
quantified. We assume that (1) low-frequency Alfven and fast waves have the
same spectral shape and the same amplitude of power spectral density; (2) these
waves eventually reach ion cyclotron frequencies due to a turbulence cascade;
(3) kinetic wave-particle interaction powers the solar wind. The existence of
alpha particles in a dominant proton/electron plasma can trigger linear mode
conversion between oblique fast-whistler and hybrid alpha-proton cyclotron
waves. The fast-cyclotron waves undergo both alpha and proton cyclotron
resonances. The alpha cyclotron resonance in fast-cyclotron waves is much
stronger than that in Alfven-cyclotron waves. For alpha cyclotron resonance, an
oblique fast-cyclotron wave has a larger left-handed electric field
fluctuation, a smaller wave number, a larger local wave amplitude, and a
greater energization capability than a corresponding Alfven-cyclotron wave at
the same wave propagation angle \theta, particularly at $80^\circ$ < \theta <
$90^\circ$. When Alfven-cyclotron or fast-cyclotron waves are present, alpha
particles are the chief energy recipient. The transition of preferential
energization from alpha particles to protons may be self-modulated by
differential speed and temperature anisotropy of alpha particles via the
self-consistently evolving wave-particle interaction. Therefore, fast-cyclotron
waves as a result of linear mode coupling is a potentially important mechanism
for preferential energization of minor ions in the main acceleration region of
the solar wind.",1203.2353v1
2015-06-07,Experimental observation of the interaction of propagating spin waves with Néel domain walls in a Landau domain structure,"The interaction of propagating dipolar spin waves with magnetic domain walls
is investigated in square-shaped microstructures patterned from the Heusler
compound Co$_2$Mn$_{0.6}$Fe$_{0.4}$Si. Using magnetic force microscopy, the
reversible preparation of a Landau state with four magnetic domains separated
by N\'eel domain walls is confirmed. A local spin-wave excitation using a
microstructured antenna is realized in one of the domains. It is shown by
Brillouin light scattering microscopy (BLS) that the domain structure in the
remanence state has a strong influence on the spin-wave excitation and
propagation. The domain walls strongly reflect the spin waves and can be used
as spin-wave reflectors. A comparison with micromagnetic simulations shows that
the strong reflection is due to the long-range dipolar interaction which has
important implications for the use of these spin waves for exerting an
all-magnonic spin-transfer torque.",1506.02303v1
2018-07-25,Left-handed polarized spin waves in ferromagnets induced by spin-transfer torque,"Polarization is a fundamental property of waves that refers to the
orientation of the oscillations. It has been widely used to encode information
in photonics and phononics. However, the polarization of spin waves is rarely
used yet in magnonics. The reason for this is that only the right-handed
polarized spin waves can be accommodated in ferromagnets. Here, we report that
stable left-handed polarized spin waves can be introduced into ferromagnets if
a spin-polarized electrical current is presented. The right-handed and
left-handed polarized spin waves coexist when the current density is larger
than a critical value while the system keeps stable. The results are confirmed
by micromagnetic simulations. This work provides new playgrounds to study spin
waves and points to new findings for future experimental studies.",1807.09456v2
2019-03-10,Electrical generation and propagation of spin waves in antiferromagnetic thin films,"Electrical generation of THz spin waves is theoretically explored in an
antiferromangetic nanostrip via the current-induced spin-orbit torque. The
analysis based on micromagnetic simulations clearly illustrates that the
Neel-vector oscillations excited at one end of the magnetic strip can propagate
in the form of a traveling wave when the nanostrip axis aligns with the
magnetic easy-axis. A sizable threshold is observed in the driving current
density or the torque to overcome the unfavorable anisotropy as expected. The
generated spin waves are found to travel over a long distance while the angle
of rotation undergoes continuous decay in the presence of non-zero damping. The
oscillation frequency is tunable via the strength of the spin-orbit torque,
reaching the THz regime. Other key characteristics of the spin waves such as
the phase and the chirality can also be modulated actively. The simulation
results further indicate the possibility of wave-like superposition between the
excited spin oscillations, illustrating its application as an efficient source
of spin-wave signals for information processing.",1903.04068v2
2020-03-11,Excitation and relaxation dynamics of spin-waves triggered by ultrafast photo-induced demagnetization in a ferrimagnetic insulator,"Excitation and propagation dynamics of spin waves in an iron-based garnet
film under out-of-plane magnetic field were investigated by time-resolved
magneto-optical imaging. The experimental results and the following data
analysis by phase-resolved spin-wave tomography reveal the excitation of spin
waves triggered by photo-induced demagnetization (PID) along the sample depth
direction. Moreover, the fast relaxation of PID accompanied by the spin
transfer due to spin-wave emission was observed. Possible scenarios of PID in
the garnet film are discussed. Finally, we develop a model for the spin-wave
excitation triggered by PID and explain the magnetic-field dependence in the
amplitude of the observed spin waves.",2003.05159v1
2023-02-13,Performance of high impedance resonators in dirty dielectric environments,"High-impedance resonators are a promising contender for realizing
long-distance entangling gates between spin qubits. Often, the fabrication of
spin qubits relies on the use of gate dielectrics which are detrimental to the
quality of the resonator. Here, we investigate loss mechanisms of
high-impedance NbTiN resonators in the vicinity of thermally grown
SiO\textsubscript{2} and Al\textsubscript{2}O\textsubscript{3} fabricated by
atomic layer deposition. We benchmark the resonator performance in elevated
magnetic fields and at elevated temperatures and find that the internal quality
factors are limited by the coupling between the resonator and two-level systems
of the employed oxides. Nonetheless, the internal quality factors of
high-impedance resonators exceed $10^3$ in all investigated oxide
configurations which implies that the dielectric configuration would not limit
the performance of resonators integrated in a spin-qubit device. Because these
oxides are commonly used for spin qubit device fabrication, our results allow
for straightforward integration of high-impedance resonators into spin-based
quantum processors. Hence, these experiments pave the way for large-scale,
spin-based quantum computers.",2302.06303v2
2024-02-29,Coupling a single spin to high-frequency motion,"Coupling a single spin to high-frequency mechanical motion is a fundamental
bottleneck of applications such as quantum sensing, intermediate and
long-distance spin-spin coupling, and classical and quantum information
processing. Previous experiments have only shown single spin coupling to
low-frequency mechanical resonators, such as diamond cantilevers.
High-frequency mechanical resonators, having the ability to access the quantum
regime, open a range of possibilities when coupled to single spins, including
readout and storage of quantum states. Here we report the first experimental
demonstration of spin-mechanical coupling to a high-frequency resonator. We
achieve this all-electrically on a fully suspended carbon nanotube device. A
new mechanism gives rise to this coupling, which stems from spin-orbit
coupling, and it is not mediated by strain. We observe both resonant and
off-resonant coupling as a shift and broadening of the electric dipole spin
resonance (EDSR), respectively. We develop a complete theoretical model taking
into account the tensor form of the coupling and non-linearity in the motion.
Our results propel spin-mechanical platforms to an uncharted regime. The
interaction we reveal provides the full toolbox for promising applications
ranging from the demonstration of macroscopic superpositions, to the operation
of fully quantum engines, to quantum simulators.",2402.19288v1
2016-10-20,Selective addressing of solid-state spins at the nanoscale via magnetic resonance frequency encoding,"The nitrogen-vacancy (NV) centre in diamond is a leading platform for
nanoscale sensing and imaging, as well as quantum information processing in the
solid state. To date, individual control of two NV electronic spins at the
nanoscale has been demonstrated. However, a key challenge is to scale up such
control to arrays of NV spins. Here we apply nanoscale magnetic resonance
frequency encoding to realize site-selective addressing and coherent control of
a four-site array of NV spins. Sites in the array are separated by 100 nm, with
each site containing multiple NVs separated by ~15 nm. Microcoils fabricated on
the diamond chip provide electrically tuneable magnetic-field gradients ~0.1
G/nm. Tailored application of gradient fields and resonant microwaves allow
site-selective NV spin manipulation and sensing applications, including Rabi
oscillations, imaging, and nuclear magnetic resonance (NMR) spectroscopy with
nanoscale resolution. Microcoil-based magnetic resonance of solid-state spins
provides a practical platform for quantum-assisted sensing, quantum information
processing, and the study of nanoscale spin networks.",1610.06630v1
2019-09-05,Pulsed electron spin resonance spectroscopy in the Purcell regime,"When spin relaxation is governed by spontaneous emission of a photon into the
resonator used for signal detection (the Purcell effect), the relaxation time
$T_1$ depends on the spin-resonator frequency detuning $\delta$ and coupling
constant $g$. We analyze the consequences of this unusual dependence for the
amplitude and temporal shape of a spin-echo in a number of different
experimental situations. When the coupling $g$ is distributed inhomogeneously,
we find that the effective spin-echo relaxation time measured in a saturation
recovery sequence strongly depends on the parameters of the detection echo.
When the spin linewidth is larger than the resonator bandwidth, the Fourier
components of the echo relax with different characteristic times, which implies
that the temporal shape of the echo becomes dependent on the repetition time of
the experiment. We provide experimental evidence of these effects with an
ensemble of donor spins in silicon at millikelvin temperatures measured by a
superconducting micro-resonator.",1909.02443v1
2022-01-07,Control of spin waves by spatially modulated strain,"We suggest using spatially modulated strain for control of a spin wave
propagating inside a bulk magnet. The modulation with the wave vector $q=2k$,
by virtue of magnetoelasticity, mixes spin waves with wave vectors near $k$ and
$-k$. This leads to lifting the degeneracy of the symmetric and antisymmetric
eigenstate combinations of these waves. The resulting picture reminds one of a
tunneling particle in a symmetric double-well potential. Here, a moving spin
wave being subjected to the $2k$-lattice modulation after some time alters its
propagation direction to the opposite one, and so on. The effect can be
utilized for the control of the spin-wave propagation that can be useful for
spintronic and magnonic applications. The control may include a delay line
element, filtering, and waveguide of the spin waves.",2201.02691v1
2023-07-07,Nonresonant scattering of energetic electrons by electromagnetic ion cyclotron waves: spacecraft observations and theoretical framework,"Electromagnetic ion cyclotron (EMIC) waves lead to rapid scattering of
relativistic electrons in Earth's radiation belts, due to their large
amplitudes relative to other waves that interact with electrons of this energy
range. A central feature of electron precipitation driven by EMIC waves is
deeply elusive. That is, moderate precipitating fluxes at energies below the
minimum resonance energy of EMIC waves occur concurrently with strong
precipitating fluxes at resonance energies in low-altitude spacecraft
observations. This paper expands on a previously reported solution to this
problem: nonresonant scattering due to wave packets. The quasi-linear diffusion
model is generalized to incorporate nonresonant scattering by a generic wave
shape. The diffusion rate decays exponentially away from the resonance, where
shorter packets lower decay rates and thus widen the energy range of
significant scattering. Using realistic EMIC wave packets from $\delta f$
particle-in-cell simulations, test particle simulations are performed to
demonstrate that intense, short packets extend the energy of significant
scattering well below the minimum resonance energy, consistent with our
theoretical prediction. Finally, the calculated precipitating-to-trapped flux
ratio of relativistic electrons is compared to ELFIN observations, and the wave
power spectra is inferred based on the measured flux ratio. We demonstrate that
even with a narrow wave spectrum, short EMIC wave packets can provide
moderately intense precipitating fluxes well below the minimum resonance
energy.",2307.03795v2
2023-04-02,Interedge spin resonance in the Kitaev quantum spin liquid,"The Kitaev model offers a platform for quantum spin liquids (QSLs) with
fractional excitations, itinerant Majorana fermions and localized fluxes. Since
these fractional excitations could be utilized for quantum computing, how to
create, observe, and control them through the spin degree of freedom is a
central issue. Here, we study dynamical spin transport in a wide range of
frequency for the Kitaev-Heisenberg model, by applying an AC magnetic field to
an edge of the system. We find that, in the Kitaev QSL phase, spin
polarizations at the other edge are resonantly induced in a specific spin
component, even though the static spin correlations are vanishingly small. This
interedge spin resonance appears around the input frequency over the broad
frequency range. Comparing with the dynamical spin correlations, we clarify
that the resonance is governed by the itinerant Majorana fermions with a broad
continuum excitation spectrum, which can propagate over long distances,
although it vanishes for the pure Kitaev model because of accidental degeneracy
and requires weak Heisenberg interactions. We also find that the spin
polarizations in the other spin components are weakly induced at an almost
constant frequency close to the excitation gap of the localized fluxes,
irrespective of the input frequency. These results demonstrate that the
dynamical spin transport is a powerful probe of the fractional excitations in
the Kitaev QSL. Possible experimental realization of the interedge spin
resonance is discussed.",2304.00528v2
2008-12-09,Spin-Wave Relaxation in a Quantum Hall Ferromagnet,"We study spin wave relaxation in quantum Hall ferromagnet regimes. Spin-orbit
coupling is considered as a factor determining spin nonconservation, and
external random potential as a cause of energy dissipation making spin-flip
processes irreversible. We compare this relaxation mechanism with other
relaxation channels existing in a quantum Hall ferromagnet.",0812.1703v1
1996-12-18,Spin-flip and spin-wave excitations in arbitrarily polarized quantum Hall states,"We study spin-flip and spin-wave excitations for arbitrarily polarized
quantum Hall states by employing a fermionic Chern-Simons gauge theory in the
low Zeeman energy limit. We show that the spin-flip correlation functions do
not get renormalized by the fluctuations of Chern-Simons gauge field. As a
consequence, the excitations for a given integer quantum Hall state are
identical to fractional quantum Hall states in the lowest Landau level having
the same numerator equal to the integer quantum Hall state. Fully and partially
polarized states possess only spin-wave excitations while spin-flip excitations
are possible for all states, irrespective of their polarizations.",9612163v1
2001-09-21,Spin waves in a Bose-condensed atomic spin chain,"The spin dynamics of atomic Bose-Einstein condensates confined in a
one-dimensional optical lattice is studied. The condensates at each lattice
site behave like spin magnets that can interact with each other through both
the light-induced dipole-dipole interaction and the static magnetic
dipole-dipole interaction. We show how these site-to-site dipolar interactions
can distort the ground state spin orientations and lead to the excitation of
spin waves. The dispersion relation of the spin waves is studied and possible
detection schemes are proposed.",0109415v1
2004-04-10,Nuclear Spin-Lattice Relaxation in One-Dimensional Heisenberg Ferrimagnets: Three-Magnon versus Raman Processes,"Nuclear spin-lattice relaxation in one-dimensional Heisenberg ferrimagnets is
studied by means of a modified spin-wave theory. We consider the second-order
process, where a nuclear spin flip induces virtual spin waves which are then
scattered thermally via the four-magnon exchange interaction, as well as the
first-order process, where a nuclear spin directly interacts with spin waves
via the hyperfine interaction. We point out a possibility of the three-magnon
relaxation process predominating over the Raman one and suggest model
experiments.",0404243v2
2007-04-25,Quantized spin excitations in a ferromagnetic microstrip from microwave photovoltage measurements,"Quantized spin excitations in a single ferromagnetic microstrip have been
measured using the microwave photovoltage technique. Several kinds of spin wave
modes due to different contributions of the dipole-dipole and the exchange
interactions are observed. Among them are a series of distinct dipole-exchange
spin wave modes, which allow us to determine precisely the subtle spin boundary
condition. A comprehensive picture for quantized spin excitations in a
ferromagnet with finite size is thereby established. The dispersions of the
quantized spin wave modes have two different branches separated by the
saturation magnetization.",0704.3397v1
2009-07-03,Spin correlations near the surface of a three-dimensional Heisenberg antiferromagnet,"Nearest-neighbor spin correlations are considered near the surface of a
semi-infinite spin-$\frac12$ Heisenberg antiferromagnet on a simple cubic
lattice. In the spin-wave approximation, the excitation spectrum of this model
involves bulk modes -- standing spin waves and a quasi-two-dimensional mode of
surface spin waves. These latter excitations eject the bulk excitations from
the surface region thus dividing the antiferromagnet into two parts with
different excitations. As a result absolute values of the spin correlations
near the surface exceed the bulk value. In the surface region, the pattern of
spin correlations resembles the comb structure recently obtained for the
two-dimensional case.",0907.0532v1
2011-07-06,Spin Seebeck Effect: Amplification of Spin Waves by Thermal Torque,"We observe amplification of spin-wave packets propagating along a film of
yttrium iron garnet (YIG) subject to a transverse temperature gradient. The
amplification is attributed to a spin-transfer thermal torque created by spin
currents generated by means of the spin Seebeck effect that acts on the
magnetization and opposes the relaxation. The experimental data are interpreted
with a simple theoretical model using spin-wave theory that gives an
amplification gain in very good agreement with measurements.",1107.1271v2
2024-02-29,Inertial spin waves in spin spirals,"Inertial effects in spin dynamics emerge on picosecond time scales, giving
rise to nutational excitations at THz frequencies. Here, we describe a general
framework for investigating the precessional and nutational excitations in any
type of spin structure within linear spin-wave theory. We consider the
particular cases of planar and conical spin spirals in detail. We observe a
change in the sign of the curvature of the high-frequency nutational spin-wave
band as the spiral period is decreased when passing from the ferromagnetic to
the antiferromagnetic limit. We identify conditions for the interaction
parameters where the curvature changes sign and asymptotical flat bands are
formed.",2402.19141v1
2002-01-10,"The Excitation, Propagation and Dissipation of Waves in Accretion Discs: The Non-linear Axisymmetric Case","We analyse the non-linear propagation and dissipation of axisymmetric waves
in accretion discs using the ZEUS-2D hydrodynamics code. The waves are
numerically resolved in the vertical and radial directions. Both vertically
isothermal and thermally stratified accretion discs are considered. The waves
are generated by means of resonant forcing and several forms of forcing are
considered. Compressional motions are taken to be locally adiabatic ($\gamma =
5/3$). Prior to non-linear dissipation, the numerical results are in excellent
agreement with the linear theory of wave channelling in predicting the types of
modes that are excited, the energy flux by carried by each mode, and the
vertical wave energy distribution as a function of radius. In all cases, waves
are excited that propagate on both sides of the resonance (inwards and
outwards). For vertically isothermal discs, non-linear dissipation occurs
primarily through shocks that result from the classical steepening of acoustic
waves. For discs that are substantially thermally stratified, wave channelling
is the primary mechanism for shock generation. Wave channelling boosts the Mach
number of the wave by vertically confining the wave to a small cool region at
the base of the disc atmosphere. In general, outwardly propagating waves with
Mach numbers near resonance ${\cal M}_{\rm r} \ga 0.01$ undergo shocks within a
distance of order the resonance radius.",0201149v1
2023-03-26,The Wave Energy Density and Growth Rate for the Resonant Instability in Relativistic Plasmas,"The wave instability acts in astrophysical plasmas to redistribute energy and
momentum in the absence of frequent collisions. There are many different types
of waves, and it is important to quantify the wave energy density and growth
rate for understanding what type of wave instabilities are possible in
different plasma regimes. There are many situations throughout the universe
where plasmas contain a significant fraction of relativistic particles.
Theoretical estimates for the wave energy density and growth rate are
constrained to either field-aligned propagation angles, or non-relativistic
considerations. Based on linear theory, we derive the analytic expressions for
the energy density and growth rate of an arbitrary resonant wave with an
arbitrary propagation angle in relativistic plasmas. For this derivation, we
calculate the Hermitian and anti-Hermitian parts of the relativistic-plasma
dielectric tensor. We demonstrate that our analytic expression for the wave
energy density presents an explicit energy increase of resonant waves in the
wavenumber range where the analytic expression for the growth rate is positive
(i.e., where a wave instability is driven). For this demonstration, we
numerically analyse the loss-cone driven instability, as a specific example, in
which the whistler-mode waves scatter relativistic electrons into the loss cone
in the radiation belt. Our analytic results further develop the basis for
linear theory to better understand the wave instability, and have the potential
to combine with quasi-linear theory, which allows to study the time evolution
of not only the particle momentum distribution function but also resonant wave
properties through an instability.",2303.14616v1
2009-01-13,Mercury's capture into the 3/2 spin-orbit resonance including the effect of core-mantle friction,"The rotation of Mercury is presently captured in a 3/2 spin-orbit resonance
with the orbital mean motion. The capture mechanism is well understood as the
result of tidal interactions with the Sun combined with planetary
perturbations. However, it is now almost certain that Mercury has a liquid
core, which should induce a contribution of viscous friction at the core-mantle
boundary to the spin evolution. This last effect greatly increases the chances
of capture in all spin-orbit resonances, being 100% for the 2/1 resonance, and
thus preventing the planet from evolving to the presently observed
configuration. Here we show that for a given resonance, as the chaotic
evolution of Mercury's orbit can drive its eccentricity to very low values
during the planet's history, any previous capture can be destabilized whenever
the eccentricity becomes lower than a critical value. In our numerical
integrations of 1000 orbits of Mercury over 4 Gyr, the spin ends 99.8% of the
time captured in a spin-orbit resonance, in particular in one of the following
three configurations: 5/2 (22%), 2/1 (32%) and 3/2 (26%). Although the present
3/2 spin-orbit resonance is not the most probable outcome, we also show that
the capture probability in this resonance can be increased up to 55% or 73%, if
the eccentricity of Mercury in the past has descended below the critical values
0.025 or 0.005, respectively.",0901.1843v1
2013-06-03,Thermodynamics of Ferromagnetic Spin Chains in a Magnetic Field: Impact of the Spin-Wave Interaction,"The thermodynamic properties of ferromagnetic spin chains have been the
subject of many publications. Still, the problem of how the spin-wave
interaction manifest itself in these low-temperature series has been neglected.
Using the method of effective Lagrangians, we explicitly evaluate the partition
function of ferromagnetic spin chains at low temperatures and in the presence
of a magnetic field up to three loops in the perturbative expansion where the
spin-wave interaction sets in. We discuss in detail the renormalization and
numerical evaluation of a particular three-loop graph and derive the
low-temperature series for the free energy density, energy density, heat
capacity, entropy density, as well as the magnetization and the susceptibility.
In the low-temperature expansion for the free energy density, the spin-wave
interaction starts manifesting itself at order $T^{5/2}$. In the pressure, the
coefficient of the $T^{5/2}$-term is positive, indicating that the spin-wave
interaction is repulsive. While it is straightforward to go up to three-loop
order in the effective loop expansion, the analogous calculation on the basis
of conventional condensed matter methods, such as spin-wave theory, appears to
be beyond reach.",1306.0600v1
2018-03-06,Combined Molecular and Spin Dynamics Simulation of BCC Iron with Vacancy Defects,"Utilizing an atomistic computational model which handles both translational
and spin degrees of freedom, combined molecular and spin dynamics simulations
have been performed to investigate the effect of vacancy defects on spin wave
excitations in ferromagnetic iron. Fourier transforms of space and
time-displaced correlation functions yield the dynamic structure factor,
providing characteristic frequencies and lifetimes of the spin wave modes.
Comparison of the system with a 5% vacancy concentration with pure lattice data
shows a decrease in frequency as well as a decrease in lifetime for all
transverse spin wave excitations observed. Additionally, a rugged spin wave
line shape for low-q spin waves indicates the presence of multiple localized
excitations near defect sites resulting in reduced excitation lifetimes due to
increased magnon-magnon scattering. We observe further evidence of increased
magnon-magnon scattering as the peaks in the longitudinal spin wave spectrum
become less distinct.",1803.02468v1
2018-11-28,Rectification of Spin Current in Inversion-Asymmetric Magnets with Linearly-Polarized Electromagnetic Waves,"We theoretically propose a method of rectifying spin current with a
linearly-polarized electromagnetic wave in inversion-asymmetric magnetic
insulators. To demonstrate the proposal, we consider quantum spin chains as a
simple example; these models are mapped to fermion (spinon) models via
Jordan-Wigner transformation. Using a nonlinear response theory, we find that a
dc spin current is generated by the linearly-polarized waves. The spin current
shows rich anisotropic behavior depending on the direction of the
electromagnetic wave. This is a manifestation of the rich interplay between
spins and the waves; inverse Dzyaloshinskii-Moriya, Zeeman, and
magnetostriction couplings lead to different behaviors of the spin current. The
resultant spin current is insensitive to the relaxation time of spinons, a
property of which potentially benefits a long-distance propagation of the spin
current. An estimate of the required electromagnetic wave is given.",1811.11515v1
2018-07-09,Spin wave dynamics in artificial anti spin-ice systems: experimental and theoretical investigations,"Reversed structures of artificial spin-ice systems, where elongated holes
with elliptical shape (antidots) are arranged into a square array with two
orthogonal sublattices, are referred to as anti-squared spin-ice. Using
Brillouin light scattering spectroscopy and plane wave method calculations, we
investigate the spin wave propagation perpendicular to the applied field
direction for two 20 nm thick Permalloy nanostructures which differ by the
presence of single and double elliptical antidots. For the spin waves
propagation along the principal antidot lattice axis, the spectrum consists of
flat bands separated by several frequency gaps which are the effect of spin
wave amplitude confinement in the regions between antidots. Contrarily, for
propagation direction at 45 degrees with respect to the antidot symmetry axis,
straight and narrow channels of propagation are formed, leading to broadening
of bands and closing of the magnonics gaps. Interestingly, in this case, extra
magnonic band gaps occur due to the additional periodicity along this
direction. The width and the position of these gaps depend on the presence of
single or double antidots. In this context, we discuss possibilities for the
tuning of spin wave spectra in anti-squared spin ice structures.",1807.03016v1
2019-03-07,Investigating optically-excited THz standing spin waves using noncollinear magnetic bilayers,"We investigate optically excited THz standing spin waves in noncollinear
magnetic bilayers. Using femtosecond laser-pulse excitation, a spin current is
generated in the first ferromagnetic (FM) layer, and flows through a conductive
spacer layer to be injected into the second (transverse) FM layer, where it
exerts a spin-transfer torque on the magnetization and excites higher-order
standing spin waves. We show that the noncollinear magnetic bilayer is a
convenient tool that allows easy excitation of THz spin waves, and can be used
to investigate the dispersion and thereby the spin wave stiffness parameter in
the thin-film regime. This is experimentally demonstrated using wedge-shaped Co
and CoB (absorption) layers. Furthermore, the damping of these THz spin waves
is investigated, showing a strong increase of the damping with decreasing
absorption layer thickness, much stronger than expected from interface spin
pumping effects. Additionally, a previously unseen sudden decrease in the
damping for the thinnest films is observed. A model for the additional damping
contribution incorporating both these observations is proposed.",1903.02802v1
2006-02-08,Linear waves around static dyon solution of nonlinear electrodynamics,"Nonlinear electrodynamics model in hypercomplex form is considered. Its
linearization around a solution is obtained. The appropriate problem for linear
waves around static dyon solution (SDS) of Born-Infeld electrodynamics is
investigated. Two types of wave scattering on SDS are considered: dissipative
(with momentum transmission from plane wave to SDS) and non-dissipative (for
SDS imbedded to an equilibrium wave background). Resonance phenomenon in the
problem is discovered and some resonance frequencies are obtained by using a
numerical method. The form of resonance wave modes are discussed. The sum of a
plane wave (as the elementary component of the wave background) with one
resonance mode is considered. The appropriate energy density is investigated at
infinity. The averaged energy density is demonstrated to have the term
proportional to inverse radius. This fact allow to consider such field
configurations as the cause of gravitational interaction, taking into account
the effective Riemann space effect discovered in my previous works. A behavior
of the linearized solution at origin of coordinates and the problem beyond the
linearization are discussed.",0602079v2
2010-01-25,Nonlinear propagation of Alfven waves driven by observed photospheric motions: Application to the coronal heating and spicule formation,"We have performed MHD simulations of Alfven wave propagation along an open
flux tube in the solar atmosphere. In our numerical model, Alfven waves are
generated by the photospheric granular motion. As the wave generator, we used a
derived temporal spectrum of the photospheric granular motion from G-band
movies of Hinode/SOT. It is shown that the total energy flux at the corona
becomes larger and the transition region height becomes higher in the case when
we use the observed spectrum rather than white/pink noise spectrum as the wave
generator. This difference can be explained by the Alfven wave resonance
between the photosphere and the transition region. After performing Fourier
analysis on our numerical results, we have found that the region between the
photosphere and the transition region becomes an Alfven wave resonant cavity.
We have confirmed that there are at least three resonant frequencies, 1, 3 and
5 mHz, in our numerical model. Alfven wave resonance is one of the most
effective mechanisms to explain the dynamics of the spicules and the sufficient
energy flux to heat the corona.",1001.4307v1
2020-04-17,S-band electron spin resonance spectroscopy using a short-circuited coplanar waveguide resonator,"In this work, we study the development of a coplanar waveguide (CPW)
resonator and its use in an electron spin resonance (ESR) spectrometer. The CPW
resonator is designed to operate in S-band. It has a short circuit
configuration which leads to miniaturization. It is so constructed such that it
has a characteristic impedance of 50 ohms. Detailed electromagnetic simulation
with a particular emphasis on the excitation of the structure has been
performed for this resonator owing to its uniplanar nature. The design
parameters and the electromagnetic field distribution are obtained from the
simulation. The resonator is fabricated using optical lithography with a rapid
prototyping technique. The characteristic response of the resonator is measured
by coupling it to a Vector Network Analyzer (VNA). The ESR absorption spectrum
of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) is captured by using this
resonator in reflection geometry. The microwave magnetic field distribution at
the sample position is investigated.The measured g-factor value is found to be
consistent with that reported in the literature. The quality factor of this
resonator is found to be low and this makes it suitable for use in a Pulsed ESR
spectrometer.",2004.08061v1
2014-04-11,Detection and Parameter Estimation of Gravitational Waves from Compact Binary Inspirals with Analytical Double-Precessing Templates,"We study the performance of various analytical frequency-domain templates for
detection and parameter estimation of gravitational waves from spin-precessing,
quasi-circular, compact binary inspirals. We begin by assessing the extent to
which non-spinning, spin-aligned, and the new (analytical, frequency-domain,
small-spin) double-precessing frequency-domain templates can be used to detect
signals from such systems. For effective, dimensionless spin values above
$0.2$, the use of non-spinning or spin-aligned templates for detection purposes
will result in a loss of up to $30%$ of all events, while in the case of the
double-precessing model, this never exceeds $6%$. Moreover, even for signals
from systems with small spins, non-spinning and spin-aligned templates
introduce large biases in the extracted masses and spins. The use of a model
that encodes spin-induced precession effects, such as the double-precessing
model, improves the mass and spin extraction by up to an order of magnitude.
The additional information encoded in the spin-orbit interaction is invaluable
if one wishes to extract the maximum amount of information from gravitational
wave signals.",1404.3180v2
2021-09-12,"Spin excitation spectra in helimagnetic states: proper-screw, cycloid, vortex crystal, and hedgehog lattice","We investigate the spin excitation spectra in chiral and polar magnets by the
linear spin-wave theory for an effective spin model with symmetric and
antisymmetric long-range interactions. In one dimension, we obtain the analytic
form of the dynamical spin structure factor for proper-screw and cycloidal
helical spin states with uniform twists, which shows a gapless mode with strong
intensity at the helical wave number. When introducing spin anisotropy in the
symmetric interactions, we numerically show that the stable spin spirals become
elliptically anisotropic with nonuniform twists and the spin excitation is
gapped. In higher dimensions, we find that similar anisotropy stabilizes
multiple-$Q$ spin states, such as vortex crystals and hedgehog lattices. We
show that the anisotropy in these states manifests itself in the dynamical spin
structure factor: a strong intensity in the transverse components to the wave
number appears only when the helical wave vector and the corresponding easy
axis are perpendicular to each other. Our findings could be useful not only to
identify the spin structure but also to deduce the stabilization mechanism by
inelastic neutron scattering measurements.",2109.05628v2
2021-06-16,Reactive helicity and reactive power in nanoscale optics: Evanescent waves. Kerker conditions. Optical theorems and reactive dichroism,"We put forward the complex helicity theorem. It constitutes a novel law that
rules the build-up of the reactive helicity through its zero time-average flow.
Its imaginary Poynting momentum accounts for the accretion of reactive power,
are illustrated in: evanescent waves and fields scattered from
magnetodielectric dipolar nanoparticles. As for the former, we show that its
reactive helicity may be experimentally observed as we introduce a reactive
spin momentum and a reactive orbital momentum in terms of which we express the
imaginary field momentum, whose transversal component produces an optical force
on a magnetoelectric particle that, as we illustrate, may surpass and can be
discriminated from, the known force due to the so-called extraordinary
momentum. We also uncover a non-conservative force on such a magnetoelectric
particle, acting in the decay direction of the evanescent wave, and that may
also be discriminated from the standard gradient force; thus making the
reactive power of the wavefield also observable. Concerning the light scattered
by magnetoelectric nanoparticles, we establish two optical theorems that govern
the accretion of reactive helicity and reactive power on extinction of incident
wave helicity and energy. Like a nule total -- internal plus external --
reactive power is at the root of a resonant scattered power, we show that a
zero total reactive helicity underlies a resonant scattered helicity. The first
Kerker condition, under which the particle becomes dual on illumination with
circularly polarized light, we demonstrate to amount to a nule overall
scattered reactive helicity. and emission. We discover a discriminatory
property of the reactive helicity of chiral light incident on a chiral
nanoparticle by excitation of the external reactive power. This for optical
near-field enantiomeric separation, we call reactive dichroism.",2106.08662v2
2008-08-10,Low frequency elastic wave propagation in 2D locally resonant phononic crystal with asymmetric resonator,"The resonance modes and the related effects to the transmission of elastic
waves in a two dimensional phononic crystal formed by periodic arrangements of
a two blocks unit cell in one direction are studied. The unit cell consists of
two asymmetric elliptic cylinders coated with silicon rubber and embedded in a
rigid matrix. The modes are obtained by the semi-analytic method in the least
square collocation scheme and confirmed by the finite element method
simulations. Two resonance modes, corresponding to the vibration of the
cylinder along the long and short axes, give rise to resonance reflections of
elastic waves. One mode in between the two modes, related to the opposite
vibration of the two cylinders in the unit cell in the direction along the
layer, results in the total transmission of elastic waves due to zero effective
mass density at the frequency. The resonance frequency of this new mode changes
continuously with the orientation angle of the elliptic resonator.",0808.1396v1
2019-03-14,"Quartet, higher order and near resonant interactions in nonlinear wave equations","Motivated by problems arising in geophysical fluid dynamics, we investigate
resonant and near resonant wave interactions in nonlinear wave equations with
quadratic nonlinearity, We place a special focus on interactions between slow
wave modes, with zero frequency in the linear limit, and fast modes. These
regularly occur in geophysical fluid systems with conserved potential vorticity
or similar conserved quantities. A general multi-scale asymptotic expansion is
used to show how the higher order nonlinear interaction coefficients are
derived as a combination of the first order terms arising at the triad
interaction level. From the general nth-order interaction coefficient we
present a proof by induction how the limiting effect for particular
combinations of slow and fast modes pushes their interactions to a slower
timescale, and we show how this is linked to the form of the conserved
quantities. We compare near resonant expansions with exact resonant expansions,
and show how near-resonances allow higher order expansions to be reduced to
just the most dominant contributions. These contributions then occur at one
order higher in the expansion when compared to the analogous exact resonance
expansion.",1903.06265v1
2022-06-14,Statistics of rogue waves in isotropic wave fields,"We investigate the statistics of rogue waves occurring in the inverse cascade
of surface gravity wave turbulence. In such statistically homogeneous,
stationary and isotropic wave fields, low-frequency waves are generated by
nonlinear interactions rather than directly forced by a wave maker. This
provides a laboratory realization of arguably the simplest nonlinear sea state,
in which long-time acquisitions are performed and compared with theoretical
models. The analysis of thousands of rogue waves reveals that some of their
properties crucially depend on four-wave resonant interactions, large crests
being for instance more likely than predicted by second-order models.",2206.06681v1
1998-10-02,"Parametrically Excited Surface Waves: Two-Frequency Forcing, Normal Form Symmetries, and Pattern Selection","Motivated by experimental observations of exotic standing wave patterns in
the two-frequency Faraday experiment, we investigate the role of normal form
symmetries in the pattern selection problem. With forcing frequency components
in ratio m/n, where m and n are co-prime integers, there is the possibility
that both harmonic and subharmonic waves may lose stability simultaneously,
each with a different wavenumber. We focus on this situation and compare the
case where the harmonic waves have a longer wavelength than the subharmonic
waves with the case where the harmonic waves have a shorter wavelength. We show
that in the former case a normal form transformation can be used to remove all
quadratic terms from the amplitude equations governing the relevant resonant
triad interactions. Thus the role of resonant triads in the pattern selection
problem is greatly diminished in this situation. We verify our general results
within the example of one-dimensional surface wave solutions of the
Zhang-Vinals model of the two-frequency Faraday problem. In one-dimension, a
1:2 spatial resonance takes the place of a resonant triad in our investigation.
We find that when the bifurcating modes are in this spatial resonance, it
dramatically effects the bifurcation to subharmonic waves in the case of
forcing frequencies are in ratio 1/2; this is consistent with the results of
Zhang and Vinals. In sharp contrast, we find that when the forcing frequencies
are in ratio 2/3, the bifurcation to (sub)harmonic waves is insensitive to the
presence of another spatially-resonant bifurcating mode.",9810003v1
2017-08-16,Effects of group velocity and multi-plasmon resonances on the modulation of Langmuir waves in a degenerate plasma,"We study the nonlinear wave modulation of Langmuir waves (LWs) in a fully
degenerate plasma. Using the Wigner-Moyal equation coupled to the Poisson
equation and the multiple scale expansion technique, a modified nonlocal
nonlinear Schr{\""{o}}dinger (NLS) equation is derived which governs the
evolution of LW envelopes in degenerate plasmas. The nonlocal nonlinearity in
the NLS equation appears due to the group velocity and multi-plasmon
resonances, i.e., resonances induced by the simultaneous particle absorption of
multiple wave quanta. We focus on the regime where the resonant velocity of
electrons is larger than the Fermi velocity and thereby the linear Landau
damping is forbidden. As a result, the nonlinear wave-particle resonances due
to the group velocity and multi-plasmon processes are the dominant mechanisms
for wave-particle interaction. It is found that in contrast to classical or
semiclassical plasmas, the group velocity resonance does not necessarily give
rise the wave damping in the strong quantum regime where $ \hbar k\sim mv_{F}$
with $\hbar$ denoting the reduced Planck's constant, $m$ the electron mass and
$v_F$ the Fermi velocity, however, the three-plasmon process plays a dominant
role in the nonlinear Landau damping of wave envelopes. In this regime, the
decay rate of the wave amplitude is also found to be higher compared to that in
the modest quantum regime where the multi-plasmon effects are forbidden.",1708.04965v3
2011-08-01,On Resonant Waves in Lattices,"Mathematical modeling of resonant waves propagating in 2D periodic infinite
lattices is conducted. Rectangular-cell, triangular-cell and hexagonal-cell
lattices are considered. Eigenvalues (here eigenfrequencies) of steady-state
problems are determined, and dispersion properties of free waves are described.
We show that the frequency spectra of the models possess several resonant
points located both at the boundary of pass/stop bands and in the interior of a
pass band. Boundary value problems with a local monochromatic source are
explored, and peculiarities of resonant waves are revealed. Asymptotic
solutions are compared with the results of computer simulation. Special
attention is given to line-localized primitive waveforms at the resonance
frequencies and to the wave beaming phenomena at a resonant excitation.",1108.0357v1
2011-12-14,Resonant Matter Wave Amplification in Mean Field Theory,"We develop a Green's function based mean-field theory for coherent mixing of
matter- and light-waves. To demonstrate the utility of this approach, we
analyse a co-propagating Raman matter-wave amplifier. We find that for a given
laser intensity, a significantly faster amplification process can be achieved
employing resonant rather than off-resonance driving. The ratio of the
matter-wave gain to atom loss-rate due to spontaneous emission is given by the
optical depth of the sample, and is the same both on- and off-resonance.
Furthermore, we show that for short-times, the single-mode approximation for
the matter-waves gives exact agreement with the full spatial dynamics. For long
times, the off-resonant case shows suppressed amplification due to a spatially
inhomogenous AC Stark shift associated with laser depletion. This suppression
is absent on-resonance, where the AC Stark shift is absent.",1112.3325v1
2015-10-18,Resonant Combinatorial Frequency Generation Induced by a PT-symmetric Periodic Layered Stack,"The nonlinear interaction of waves in PT-symmetric periodic stacks with an
embedded nonlinear anisotropic dielectric layer illuminated by plane waves of
two tones is examined. The three-wave interaction technique is applied to study
the nonlinear processes. It is shown that the intensity of the three-wave
mixing process can be significantly enhanced in resonant cavities based on
PT-symmetric periodic structures, especially as the pumping wave frequency is
near the coherent perfect absorber-lasing resonances. The main mechanisms and
properties of the combinatorial frequency generation and emission from the
stacks are illustrated by the simulation results and the effect of the layer
arrangement in PT-symmetric walls of resonator on the stack nonlinear response
is discussed. The enhanced efficiency of the frequency conversion at Wolf-Bragg
resonances is demonstrated. It has been shown that Wolf-Bragg resonances of
very high orders may lead to the global maxima and nulls of the scattered
field. The analysis of the effect of losses in nonlinear dielectric layer on
the combinatorial frequency generation efficiency has shown that the rate of
losses may amplify the intensity of the frequency mixing process.",1510.05243v1
2024-03-07,Enhanced near-complete absorption of electromagnetic waves by dual resonance in a magnetized plasma,"There has been significant interest lately in the study of Electromagnetic
(EM) waves interacting with magnetized plasmas. The variety of resonances and
the existence of several pass and stop bands in the dispersion curve for
different orientations of the magnetic field offer new mechanisms of EM wave
energy absorption (PhysRevE.105.055209,
Juneja_2023,vashistha2022localized,vashistha2020new). By an appropriate choice
of inhomogeneous magnetic field, one can construct a configuration wherein the
same EM wave pulse encounters more than one resonance in the plasma. A 2-D
Particle - In - Cell (PIC) simulation using the OSIRIS4.0 platform has been
carried out for the case of dual resonance. It is observed that in the presence
of dual resonance, there is a significant enhancement in leading to almost
complete absorption of laser energy by the plasma in certain cases. A detailed
study of the influence of the relative location of the resonances, the effect
of high input EM wave intensity, etc., has also been carried out.",2403.04462v1
2008-01-04,Spin-hybrid-phonon resonance in anisotropic quantum dots,"We have studied the absorption of electromagnetic radiation of an anisotropic
quantum dot taking into account the spin-flip processes that is associated with
the interaction of the electrons with optical phonons. It is shown that these
processes lead to the resonance absorption. Explicit formula is derived for the
absorption coefficient. The positions of the resonances peaks are found.",0801.0666v1
2020-05-12,Propagation of spin waves through a Néel domain wall,"Spin waves have the potential to be used as a new platform for data transfer
and processing as they can reach wavelengths in the nanometer range and
frequencies in the terahertz range. To realize a spin-wave device, it is
essential to be able to manipulate the amplitude as well as the phase of spin
waves. Several theoretical and recently also experimental works have shown that
the spin-wave phase can be manipulated by the transmission through a domain
wall (DW). Here, we study propagation of spin waves through a DW by means of
micro-focused Brillouin light scattering microscopy ($\mu$BLS). The acquired 2D
spin-wave intensity maps reveal that spin-wave transmission through a N\'eel DW
is influenced by a topologically enforced circular Bloch line in the DW center
and that the propagation regime depends on the spin-wave frequency. In the
first regime, two spin-wave beams propagating around the circular Bloch line
are formed, whereas in the second regime, spin waves propagate in a single
central beam through the circular Bloch line. Phase-resolved $\mu$BLS
measurements reveal a phase shift upon transmission through the domain wall for
both regimes. Micromagnetic modelling of the transmitted spin waves unveils a
distortion of their phase fronts which needs to be taken into account when
interpreting the measurements and designing potential devices. Moreover, we
show, by means of micromagnetic simulations, that an external magnetic field
can be used to move the circular Bloch line within the DW and to manipulate
spin-wave propagation.",2005.05690v2
2014-12-08,Resonant surface plasmons of a metal nanosphere can be considered in the way of propagating surface plasmons,"Assuming that the resonant surface plasmons on a spherical nanoparticle is
formed by standing waves of two counter-propagating surface plasmon waves along
the surface, by using Mie theory simulation, we find that the dispersions of
surface plasmon resonant modes supported by silver nanospheres match that of
the surface plasmons on a semi-infinite medium-silver interface very well. This
suggests that the resonant surface plasmons of a metal nanosphere can be
treated as a propagating surface plasmon wave.",1412.2664v1
2022-12-08,Electroelastic metasurface with resonant piezoelectric shunts for tunable wavefront control,"This study presents a tunable phase-modulated metasurface composed of
periodically distributed piezoelectric patches with resonant-type shunt
circuits. The fully coupled electromechanical model is established to study the
transmission characteristics of the metasurface unit and validated through
numerical and experimental studies. Based on the analysis of the metasurface
unit, we first explore the performance of electroelastic metasurface with
single-resonant shunts and then extend its capability with multi-resonant
shunts. By only tuning the electric loads in the shunt circuits, we utilize the
proposed metasurface to accomplish wave deflection and wave focusing of A0 mode
Lamb waves at different angles and focal points, respectively.",2212.04057v1
2020-03-25,Nonreciprocity of spin waves in noncollinear magnets due to the Dzyaloshinskii-Moriya interaction,"Broken inversion symmetry in combination with the spin-orbit interaction
generates a finite Dzyaloshinskii-Moriya interaction (DMI), which can induce
noncollinear spin textures of chiral nature. The DMI is characterized by an
interaction vector whose magnitude, direction and symmetries are crucial to
determine the stability of various spin textures, such as skyrmions and spin
spirals. The DMI can be measured from the nonreciprocity of spin waves in
ferromagnets, which can be probed via inelastic scattering experiments. In a
ferromagnet, the DMI can modify the spin-wave dispersion, moving its minimum
away from the $\Gamma$ point. Spin waves propagating with opposite wavevectors
are then characterized by different group velocities, energies and lifetimes,
defining their nonreciprocity. Here, we address the case of complex spin
textures, where the manifestation of DMI-induced chiral asymmetries remains to
be explored. We discuss such nonreciprocal effects and propose ways of
accessing the magnitude and direction of the DMI vectors in the context of
spin-polarized or spin-resolved inelastic scattering experiments. We show that
only when a periodic magnetic system has finite net magnetization, that is,
when the vector sum of all magnetic moments is nonzero, can it present a total
nonreciprocal spin-wave spectrum. However, even zero-net-magnetization systems,
such as collinear antiferromagnets and cycloidal spin spirals, can have
spin-wave modes that are individually nonreciprocal, while the total spectrum
remains reciprocal.",2003.11649v1
2015-03-13,Single Spin Optically Detected Magnetic Resonance with E-Band Microwave Resonators,"Magnetic resonance with ensembles of electron spins is nowadays performed in
frequency ranges up to 240 GHz and in corresponding magnetic fields of up to 10
T. However, experiments with single electron and nuclear spins so far only
reach into frequency ranges of several 10 GHz, where existing coplanar
waveguide structures for microwave (MW) delivery are compatible with single
spin readout techniques (e.g. electrical or optical readout). Here, we explore
the frequency range up to 90 GHz, respectively magnetic fields of up to
$\approx 3\,$T for single spin magnetic resonance in conjunction with optical
spin readout. To this end, we develop MW resonators with optical single spin
access. In our case, rectangular E-band waveguides guarantee low-loss supply of
microwaves to the resonators. Three dimensional cavities, as well as coplanar
waveguide resonators enhance MW fields by spatial and spectral confinement with
a MW efficiency of $1.36\,\mathrm{mT/\sqrt{W}}$. We utilize single NV centers
as hosts for optically accessible spins, and show, that their properties
regarding optical spin readout known from smaller fields (<0.65 T) are retained
up to fields of 3 T. In addition, we demonstrate coherent control of single
nuclear spins under these conditions. Furthermore, our results extend the
applicable magnetic field range of a single spin magnetic field sensor.
Regarding spin based quantum registers, high fields lead to a purer product
basis of electron and nuclear spins, which promises improved spin lifetimes.
For example, during continuous single-shot readout the $^{14}$N nuclear spin
shows second-long longitudinal relaxation times.",1503.04134v1
2013-12-11,"Magnonic Band Structure, Complete Bandgap and Collective Spin Wave Excitation in Nanoscale Two--Dimensional Magnonic Crystals","We present the observation of a complete bandgap and collective spin wave
excitation in two-dimensional magnonic crystals comprised of arrays of
nanoscale antidots and nanodots, respectively. Considering that the frequencies
dealt with here fall in the microwave band, these findings can be used for the
development of suitable magnonic metamaterials and spin wave based signal
processing. We also present the application of a numerical procedure, to
compute the dispersion relations of spin waves for any high symmetry direction
in the first Brillouin zone. The results obtained from this procedure has been
reproduced and verified by the well established plane wave method for an
antidot lattice, when magnetization dynamics at antidot boundaries is pinned.
The micromagnetic simulation based method can also be used to obtain
iso--frequency countours of spin waves. Iso--frequency contours are analougous
of the Fermi surfaces and hence, they have the potential to radicalize our
understanding of spin wave dynamics. The physical origin of bands, partial and
full magnonic bandgaps has been explained by plotting the spatial distribution
of spin wave energy spectral density. Although, unfettered by rigid assumptions
and approximations, which afflict most analytical methods used in the study of
spin wave dynamics, micromagnetic simulations tend to be computationally
demanding. Thus, the observation of collective spin wave excitation in the case
of nanodot arrays, which can obviate the need to perform simulations may also
prove to be valuable.",1312.3044v1
2017-07-12,X-Ray Microscopy of Spin Wave Focusing using a Fresnel Zone Plate,"Magnonics, i.e. the artificial manipulation of spin waves, is a flourishing
field of research with many potential uses in data processing within reach.
Apart from the technological applications the possibility to directly influence
and observe these types of waves is of great interest for fundamental research.
Guidance and steering of spin waves has been previously shown and lateral spin
wave confinement has been achieved. However, true spin wave focusing with both
lateral confinement and increase in amplitude has not been shown before. Here,
we show for the first time spin wave focusing by realizing a Fresnel zone plate
type lens. Using x-ray microscopy we are able to directly image the propagation
of spin waves into the nanometer sized focal spot. Furthermore, we observe that
the focal spot can be freely moved in a large area by small variations of the
bias field. Thus, this type of lens provides a steerable intense nanometer
sized spin wave source. Potentially, this could be used to selectively
illuminate magnonic devices like nano oscillators with a steerable spin wave
beam.",1707.03664v1
2017-03-11,Magnonic crystals - prospective structures for shaping spin waves in nanoscale,"We have investigated theoretically band structure of spin waves in magnonic
crystals with periodicity in one-(1D), two- (2D) and three-dimensions (3D). We
have solved Landau-Lifshitz equation with the use of plane wave method, finite
element method in frequency domain and micromagnetic simulations in time domain
to find the dynamics of spin waves and spectrum of their eigenmodes. The spin
wave spectra were calculated in linear approximation. In this paper we show
usefulness of these methods in calculations of various types of spin waves. We
demonstrate the surface character of the Damon-Eshbach spin wave in 1D magnonic
crystals and change of its surface localization with the band number and
wavenumber in the first Brillouin zone. The surface property of the spin wave
excitation is further exploited by covering plate of the magnonic crystal with
conductor. The band structure in 2D magnonic crystals is complex due to
additional spatial inhomogeneity introduced by the demagnetizing field. This
modifies spin wave dispersion, makes the band structure of magnonic crystals
strongly dependent on shape of the inclusions and type of the lattice. The
inhomogeneity of the internal magnetic field becomes unimportant for magnonic
crystals with small lattice constant, where exchange interactions dominate. For
3D magnonic crystals, characterized by small lattice constant, wide magnonic
band gap is found. We show that the spatial distribution of different materials
in magnonic crystals can be explored for tailored effective damping of spin
waves.",1703.04012v1
2012-07-25,A Resonantly-Excited Disk-Oscillation Model of High-Frequency QPOs of Microquasars,"A possible model of twin high-frequency QPOs (HF QPOs) of microquasars is
examined. The disk is assumed to have global magnetic fields and to be deformed
with a two-armed pattern. In this deformed disk, set of a two-armed ($m=2$)
vertical p-mode oscillation and an axisymmetric ($m=0$) g-mode oscillation are
considered. They resonantly interact through the disk deformation when their
frequencies are the same. This resonant interaction amplifies the set of the
above oscillations in the case where these two oscillations have wave energies
of opposite signs. These oscillations are assumed to be excited most
efficiently in the case where the radial group velocities of these two waves
vanish at the same place. The above set of oscillations is not unique,
depending on the node number, $n$, of oscillations in the vertical direction.
We consider that the basic two sets of oscillations correspond to the twin
QPOs. The frequencies of these oscillations depend on disk parameters such as
strength of magnetic fields. For observational mass ranges of GRS 1915+105, GRO
J1655-40, XTE J1550-564, and H1743-322, spins of these sources are estimated.
High spins of these sources can be described if the disks have weak poloidal
magnetic fields as well as toroidal magnetic fields of moderate strength. In
this model the 3 : 2 frequency ratio of high-frequency QPOs is not related to
their excitation, but occurs by chance.",1207.5882v1
2013-08-05,Physics picture from neutron scattering study on Fe-based superconductors,"Neutron scattering, with its ability to measure the crystal structure, the
magnetic order, and the structural and magnetic excitations, plays an active
role in investigating various families of Fe-based high-Tc superconductors.
Three different types of antiferromag- netic orders have been discovered in the
Fe plane, but two of them cannot be explained by the spin-density-wave (SDW)
mechanism of nesting Fermi surfaces. Noticing the close relation between
antiferromagnetic order and lattice distortion in orbital ordering from
previous studies on manganites and other oxides, we have advocated orbital or-
dering as the underlying common mechanism for the structural and
antiferromagnetic transitions in the 1111, 122 and 11 parent compounds. We
observe the coexistence of antiferromagnetic order and superconductivity in the
(Ba,K)Fe2 As2 system, when its phase separation is generally accepted. Optimal
Tc is proposed to be controlled by the local FeAs4 tetrahedron from our
investigation on the 1111 materials. The Bloch phase coherence of the Fermi
liquid is found crucial to the occurrence of bulk superconductiv- ity in iron
chalcogenides of both the 11 and the 245 families. Iron chalcogenides carry a
larger staggered magnetic moment (> 2{\mu}B /Fe) than that in iron pnictides (<
1{\mu}B /Fe) in the antiferromagnetic order. Normal state magnetic excitations
in the 11 supercon- ductor are of the itinerant nature while in the 245
superconductor the spin-waves of localized moments. The observation of
superconducting resonance peak provides a cru- cial piece of information in
current deliberation of the pairing symmetry in Fe-based superconductors.",1308.1040v1
2013-08-21,Intense low-energy ferromagnetic fluctuations in the antiferromagnetic heavy-fermion metal CeB6,"Heavy-fermion metals exhibit a plethora of low-temperature ordering
phenomena, among them the so-called hidden-order phases that in contrast to
conventional magnetic order are invisible to standard neutron diffraction. One
of the oldest and structurally simplest hidden-order compounds, CeB6, became
famous for an elusive phase that was attributed to the antiferroquadrupolar
ordering of cerium-4f moments. In its ground state, CeB6 also develops a more
usual antiferromagnetic (AFM) order. Hence, its essential low-temperature
physics was always considered to be solely governed by AFM interactions between
the dipolar and multipolar Ce moments. Here we overturn this established
perspective by uncovering an intense ferromagnetic (FM) low-energy collective
mode that dominates the magnetic excitation spectrum of CeB6. Our inelastic
neutron-scattering data reveal that the intensity of this FM excitation by far
exceeds that of conventional spin-wave magnons emanating from the AFM wave
vectors, thus placing CeB6 much closer to a FM instability than could be
anticipated. This propensity of CeB6 to ferromagnetism may account for much of
its unexplained behavior, such as the existence of a pronounced electron spin
resonance, and should lead to a substantial revision of existing theories that
have so far largely neglected the role of FM interactions.",1308.4491v1
2015-06-04,Magnetic neutron scattering studies on the Fe-based superconductor system Fe$_{1+y}$Te$_{1-x}$Se$_x$,"I present a brief overview on the interplay between magnetism and
superconductivity in one of the Fe-based superconductor systems, \fts, where
the research of our group has centered. The parent compound Fe$_{1+y}$Te is an
antiferromagnet; with Se doping, antiferromagnetic order is suppressed,
followed by the appearance of superconductivity; optimal superconductivity is
achieved when $x\sim50\%$, with a superconducting temperature \tc of
$\sim$15~K. The parent compound has an in-plane magnetic ordering wave vector
around (0.5,\,0) (using the tetragonal notation with two Fe atoms per cell).
When Se concentration increases, the spectral weight appears to be shifted to
the wave vector around (0.5,\,0.5), accompanying the optimization of
superconductivity. A neutron-spin resonance has been observed around
(0.5,\,0.5) below \tc, and is suppressed, along with superconductivity, by an
external magnetic field. Taking these evidences into account, it is concluded
that magnetism and superconductivity in this system couple to each other
closely---while the static magnetic order around (0.5,\,0) competes with
superconductivity, the spin excitations around (0.5,\,0.5) may be an important
ingredient for it. I will also discuss the nature of magnetism and substitution
effects of 3$d$ transition metals.",1506.01536v1
2015-11-11,Spin wave mediated unidirectional Vortex Core Reversal by Two Orthogonal Monopolar Field Pulses: The Essential Role of Three-dimensional Magnetization Dynamics,"Scanning transmission x-ray microscopy is employed to investigate
experimentally the reversal of the magnetic vortex core polarity in cylindrical
Ni81Fe19 nanodisks triggered by two orthogonal monopolar magnetic field pulses
with peak amplitude $B_0$, pulse length ${\tau}$=60 ps and delay time
${\Delta}$t in the range from -400 ps to +400 ps between the two pulses. The
two pulses are oriented in-plane in the x- and y-direction. We have
experimentally studied vortex core reversal as function of $B_0$ and
${\Delta}$t. The resulting phase diagram shows large regions of unidirectional
vortex core switching where the switching threshold is modulated due to
resonant amplification of azimuthal spin waves. The switching behavior changes
dramatically depending on whether the first pulse is applied in the x- or the
y-direction. This asymmetry can be reproduced by three-dimensional
micromagnetic simulations but not by two-dimensional simulations. This behavior
demonstrates that in contrast to previous experiments on vortex core reversal
the three-dimensionality in the dynamics is essential here.",1511.03486v3
2018-08-15,Excitonic collective modes in Weyl semi-metals,"Weyl semi-metals are three dimensional generalizations of graphene with
point-like Fermi surfaces. Their linear electronic dispersion leads to a window
in the particle-hole excitation spectrum which allows for undamped propagation
of collective excitations. We argue that interactions in Weyl semi-metals
generically lead to well-defined exciton modes. However, using a minimal model
for interactions, we show that the exciton binding energy is exponentially
small for weak interactions. This is due to effective two-dimensional character
in the space of particle-hole pairs that are available for bound state
formation. This is ultimately a consequence of linear electronic dispersion in
three dimensions. Nevertheless, intermediate interaction strengths can lead to
sharp spin-carrying excitonic resonances. We demonstrate this in a model Weyl
semi-metal with broken time-reversal symmetry and Hubbard interactions, using
GRPA (generalized random phase approximation) analysis. Excitons in Weyl
semi-metals have evoked interest as their condensation could lead to an axionic
charge density wave order. However, we find that the leading instability
corresponds to intra-valley spin density wave order which shifts the Weyl
points without opening a gap. Our results suggest interesting directions for
experimental studies of three dimensional Dirac systems.",1808.05233v2
2019-12-26,Orbitally-resolved ferromagnetism of monolayer CrI$_3$,"Few-layer CrI$_3$ is the most known example among two-dimensional (2D)
ferromagnets, which have attracted growing interest in recent years. Despite
considerable efforts and progress in understanding the properties of 2D magnets
both from theory and experiment, the mechanism behind the formation of in-plane
magnetic ordering in chromium halides is still under debate. Here, we propose a
microscopic orbitally-resolved description of ferromagnetism in monolayer
CrI$_3$. Starting from first-principles calculations, we construct a low-energy
model for the isotropic Heisenberg exchange interactions. We find that there
are two competing contributions to the long-range magnetic ordering in CrI$_3$:
(i) Antiferromagnetic Anderson's superexchange between half-filled $t_{2g}$
orbitals of Cr atoms; and (ii) Ferromagnetic exchange governed by the
Kugel-Khomskii mechanism, involving the transitions between half-filled
$t_{2g}$ and empty $e_g$ orbitals. Using numerical calculations, we estimate
the exchange interactions in momentum-space, which allows us to restore the
spin-wave spectrum, as well as estimate the Curie temperature. Contrary to the
nearest-neighbor effective models, our calculations suggest the presence of
sharp resonances in the spin-wave spectrum at 5--7 meV, depending on the
vertical bias voltage. Our estimation of the Curie temperature in monolayer
CrI$_3$ yields 55--65 K, which is in good agreement with experimental data.",1912.11828v1
2021-06-26,Beam-spin asymmetry $\boldsymbolΣ$ for $Σ^-$ hyperon photoproduction off the neutron,"We report a new measurement of the beam-spin asymmetry $\boldsymbol{\Sigma}$
for the $\vec{\gamma} n \rightarrow K^+\Sigma^-$ reaction using quasi-free
neutrons in a liquid-deuterium target. The new dataset includes data at
previously unmeasured photon energy and angular ranges, thereby providing new
constraints on partial wave analyses used to extract properties of the excited
nucleon states. The experimental data were obtained using the CEBAF Large
Acceptance Spectrometer (CLAS), housed in Hall B of the Thomas Jefferson
National Accelerator Facility (JLab). The CLAS detector measured reaction
products from a liquid-deuterium target produced by an energy-tagged, linearly
polarised photon beam with energies in the range 1.1 to 2.3 GeV. Predictions
from an isobar model indicate strong sensitivity to $N(1720)3/2^+$,
$\Delta(1900)1/2^-$, and $N(1895)1/2^-$, with the latter being a state not
considered in previous photoproduction analyses. When our data are incorporated
in the fits of partial-wave analyses, one observes significant changes in
$\gamma$-$n$ couplings of the resonances which have small branching ratios to
the $\pi N$ channel.",2106.13957v2
2021-06-28,Two-Hole Ground State: Dichotomy in Pairing Symmetry,"A single-hole ground state Ansatz for the two-dimensional t-J model has been
recently studied by the variational Monte Carlo (VMC) method. Such a doped hole
behaves like a ""twisted"" non-Landau quasiparticle characterized by an emergent
quantum number in agreement with exact numerics. In this work, we further
investigate the ground state of two holes by VMC. It is found that the two
holes strongly attract each other to form a pairing state with a new quantum
number the same as obtained by the numerical exact diagonalization and density
matrix renormalization group (DMRG) calculations. A unique feature of this
pairing state is a dichotomy in the pairing symmetry, i.e., a d-wave in terms
of the electron c operators and an s-wave in terms of the new quasiparticles,
as explicitly illustrated in the ground state wave function. A similar VMC
study of a two-hole wave function for the t-J two-leg ladder also yields a good
agreement with the DMRG result. We demonstrate that the pairing mechanism
responsible for the strong binding here is not due to the long-range
antiferromagnetic order nor the resonating-valence-bound pairing in the spin
background but is the consequence of the quantum phase-strings created by the
hopping of holes. The resulting spin-current pattern mediating the pairing
force is explicitly illustrated in the VMC calculation. Physical implications
to superconductivity at finite doping are also discussed.",2106.14898v2
2021-11-09,Adiabatic waveforms from extreme-mass-ratio inspirals: an analytical approach,"Scientific analysis for the gravitational-wave detector LISA will require
theoretical waveforms from extreme-mass-ratio inspirals (EMRIs) that
extensively cover all possible orbital and spin configurations around
astrophysical Kerr black holes. However, on-the-fly calculations of these
waveforms have not yet overcome the high dimensionality of the parameter space.
To confront this challenge, we present a user-ready EMRI waveform model for
generic (eccentric and inclined) orbits in Kerr spacetime, using an analytical
self-force approach. Our model accurately covers all EMRIs with arbitrary
inclination and black hole spin, up to modest eccentricity ($\lesssim 0.3$) and
separation ($\gtrsim2$--$10M$ from the last stable orbit). In that regime, our
waveforms are accurate at the leading `adiabatic' order, and they approximately
capture transient self-force resonances that significantly impact the
gravitational-wave phase. The model fills an urgent need for extensive
waveforms in ongoing data-analysis studies, and its individual components will
continue to be useful in future science-adequate waveforms.",2111.05288v3
2023-03-02,Commensurate-to-incommensurate transition of charge-density-wave order and a possible quantum critical point in pressurized kagome metal CsV$_3$Sb$_5$,"Clarifying the interplay between charge density waves (CDWs) and
superconductivity is important in the kagome metal CsV$_3$Sb$_5$, and pressure
($P$) can play a crucial role. Here, we present $^{121/123}$Sb nuclear
quadrupole resonance (NQR) measurements under hydrostatic pressures up to 2.43
GPa in CsV$_3$Sb$_5$ single crystals. We demonstrate that the CDW gradually
changes from a commensurate modulation with a star-of-David (SoD) pattern to an
incommensurate one with a superimposed SoD and Tri-hexagonal (TrH) pattern
stacking along the $c$-axis. Moreover, the linewidth $\delta\nu$ of
$^{121/123}$Sb-NQR spectra increases with cooling down to $T_{\rm CDW}$,
indicating the appearance of a short-range CDW order due to CDW fluctuations
pinned by quenched disorders. The $\delta\nu$ shows a Curie-Weiss temperature
dependence and tends to diverge at $P_{\rm c} \sim$ 1.9 GPa, suggesting that a
CDW quantum critical point (QCP) exists at $P_{\rm c}$ where $T_{\rm c}$ shows
the maximum. For $P > P_{\rm c}$, spin fluctuations are enhanced when the CDW
is suppressed. Our results suggest that the maximal $T_{\rm c}$ at $P_{\rm c}
\sim$ 1.9 GPa is related to the CDW QCP and the presence of spin fluctuations
prevent the $T_{\rm c}$ from a rapid decrease otherwise after the CDW is
completely suppressed.",2303.01225v1
2023-06-17,Multiplexing spectral line shape of waveguide transmission by photonic spin-orbit interaction,"Manipulating the spectral line shape exhibits great potential in realizing
active optical circuits with switching, sensing, and modulation capabilities.
Exploring unusual line shapes, such as Fano resonance and electromagnetically
induced transparency (EIT), has attracted substantial interest. Conventional
methods of engineering the spectral line shape have limited tunability and face
challenges in multiplexing different spectral line shapes. Here, we propose and
numerically demonstrate a new mechanism to tailor the transmission line shape
almost at will by exploiting the interference of frequency-dependent chiral
dipolar states in two helix particles sitting above a dielectric waveguide. We
show that, by tuning the polarization of the chiral dipoles and exploiting
transverse spin-orbit interaction, one can control the asymmetric
Pancharatnam-Berry geometric phase for the excited guided waves propagating in
opposite directions. The interference of the guided waves respectively excited
by the two particles can give rise to transmissions with various line shapes,
including Lorentzian-like, antiresonance-like, Fano-like, and EIT-like line
shapes, which carry an intriguing property of line shape-momentum locking,
i.e., the transmissions in opposite directions have different line shapes. Our
findings open new possibilities for multiplexed and multifunctional
nanophotonic designs with unprecedented capability of spectral-line shaping.
The proposed structures can be conveniently integrated with optical circuits
for on-chip applications.",2306.10264v1
2023-07-27,Broadband parametric amplification for multiplexed SiMOS quantum dot signals,"Spins in semiconductor quantum dots hold great promise as building blocks of
quantum processors. Trapping them in SiMOS transistor-like devices eases future
industrial scale fabrication. Among the potentially scalable readout solutions,
gate-based dispersive radiofrequency reflectometry only requires the already
existing transistor gates to readout a quantum dot state, relieving the need
for additional elements. In this effort towards scalability, traveling-wave
superconducting parametric amplifiers significantly enhance the readout
signal-to-noise ratio (SNR) by reducing the noise below typical cryogenic
low-noise amplifiers, while offering a broad amplification band, essential to
multiplex the readout of multiple resonators. In this work, we demonstrate a
3GHz gate-based reflectometry readout of electron charge states trapped in
quantum dots formed in SiMOS multi-gate devices, with SNR enhanced thanks to a
Josephson traveling-wave parametric amplifier (JTWPA). The broad, tunable 2GHz
amplification bandwidth combined with more than 10dB ON/OFF SNR improvement of
the JTWPA enables frequency and time division multiplexed readout of interdot
transitions, and noise performance near the quantum limit. In addition, owing
to a design without superconducting loops and with a metallic ground plane, the
JTWPA is flux insensitive and shows stable performances up to a magnetic field
of 1.2T at the quantum dot device, compatible with standard SiMOS spin qubit
experiments.",2307.14717v2
2024-01-23,Electronic and magnetic excitations in La$_3$Ni$_2$O$_7$,"The striking discovery of high-temperature superconductivity (HTSC) of 80 K
in a bilayer nickelate La$_3$Ni$_2$O$_7$ under a moderately high pressure of
about 14 GPa ignited a new wave of studying HTSC in nickelates. The properties
of the parental phase at ambient pressure may contain key information on basic
interactions therein and bosons that may mediate pairing giving birth to
superconductivity. Moreover, the bilayer structure of La$_3$Ni$_2$O$_7$ may
suggest a distinct minimal model in comparison to cuprate superconductors. Here
using X-ray absorption spectroscopy and resonant inelastic X-ray scattering, we
studied La$_3$Ni$_2$O$_7$ at ambient pressure, and found that Ni
3$d_{x^2-y^2}$, Ni 3$d_{z^2}$, and ligand oxygen 2$p$ orbitals dominate the
low-energy physics with a small charge-transfer energy. Remarkably,
well-defined optical-like magnetic excitations were found to soften into a
quasi-static spin-density-wave ordering, evidencing the strong electronic
correlations and rich magnetic properties. Based on a Heisenberg spin model, we
found that the inter-layer effective magnetic superexchange interaction is much
larger than the intra-layer ones, and proposed two viable magnetic structures.
Our results set the foundation for further exploration of La$_3$Ni$_2$O$_7$
superconductor.",2401.12657v1
2012-05-15,Electron spin resonance in Eu based Fe pnictides,"The phase diagrams of EuFe$_{2-x}$Co$_x$As$_2$ $(0 \leq x \leq 0.4)$ and
EuFe$_2$As$_{2-y}$P$_y$ $(0 \leq y \leq 0.43)$ are investigated by Eu$^{2+}$
electron spin resonance (ESR) in single crystals. From the temperature
dependence of the linewidth $\Delta H(T)$ of the exchange narrowed ESR line the
spin-density wave (SDW) $(T < T_{\rm SDW})$ and the normal metallic regime $(T
> T_{\rm SDW})$ are clearly distinguished. At $T > T_{\rm SDW}$ the isotropic
linear increase of the linewidth is driven by the Korringa relaxation which
measures the conduction-electron density of states at the Fermi level. For $T <
T_{\rm SDW}$ the anisotropy probes the local ligand field, while the coupling
to the conduction electrons disappears. With increasing substitution $x$ or $y$
the transition temperature $T_{\rm SDW}$ decreases linearly accompanied by a
linear decrease of the Korringa-relaxation rate from 8 Oe/K at $x=y=0$ down to
3 Oe/K at the onset of superconductivity at $x \approx 0.2$ or at $y \approx
0.3$, above which it remains nearly constant. Comparative ESR measurements on
single crystals of the Eu diluted SDW compound Eu$_{0.2}$Sr$_{0.8}$Fe$_2$As$_2$
and superconducting (SC) Eu$_{0.22}$Sr$_{0.78}$Fe$_{1.72}$Co$_{0.28}$As$_2$
corroborate the leading influence of the ligand field on the Eu$^{2+}$ spin
relaxation in the SDW regime as well as the Korringa relaxation in the normal
metallic regime. Like in Eu$_{0.5}$K$_{0.5}$Fe$_2$As$_2$ a coherence peak is
not detected in the latter compound at $T_{\rm c}=21$ K, which is in agreement
with the expected complex anisotropic SC gap structure.",1205.3318v1
2017-05-26,Dielectric permeability tensor and linear waves in spin-1/2 quantum kinetics with non-trivial equilibrium spin-distribution functions,"A consideration of waves propagating parallel to the external magnetic field
is presented. The dielectric permeability tensor is derived from quantum
kinetic equations with non-trivial equilibrium spin-distribution functions
(NTESDF) in the linear approximation on amplitude of wave perturbations. In
general case, x- and y-projections of the SDF are nonzero which is called the
non-trivial regime. Corresponding equilibrium solution is found. Contribution
of the NTESDF appears in the dielectric permeability tensor in the additive
form. It is explicitly found here. Corresponding modification in the dispersion
equation for the transverse waves is derived. Contribution of NTESDF in the
spectrum of transverse waves is calculated numerically. It is found that the
term caused by the NTESDF can be comparable with the classic terms for the
relatively small wave vectors and frequencies above the cyclotron frequency. In
majority of regimes, the extra spin caused term dominates over the spin term
found earlier, except the small frequency regime, where their contributions in
the whistler spectrum are comparable. A decrease of the left-hand circularly
polarized wave frequency, an increase of the high-frequency right-hand
circularly polarized wave frequency, and a decrease of frequency changing by an
increase of frequency at the growth of the wave vector for the whistler are
found. A dramatic decrease of the spin wave frequency resulting in several
times larger group velocity of the spin wave is found either. Found dispersion
equations are used for obtaining of an effective quantum hydrodynamics
reproducing these results. This generalization requires the introduction of
corresponding equation of state for the thermal part of the spin current in the
spin evolution equation.",1705.09738v1
2022-03-21,Scattering of spin waves by a Bloch domain wall: effect of the dipolar interaction,"It is known that a Bloch domain wall in an anisotropic ferromagnet is
transparent to spin waves. This result is derived by approximating the dipolar
interaction between magnetic moments by an effective anisotropy interaction. In
this paper we study the the scattering of spin waves by a domain wall taking
into account the full complexity of the dipolar interaction, treating it
perturbatively in the distorted wave Born approximation. Due to the
peculiarities of the dipolar interaction, the implementation of this
approximation is not straightforward. The difficulties are circumvented here by
realizing that the contribution of the dipolar interaction to the spin wave
operator can be split into two terms: i) an operator that commutes with the
spin wave operator in absence of dipolar interaction, and ii) a local operator
suitable to be treated as a perturbation in the distorted wave Born
approximaton. We analyze the scattering parameters obtained within this
approach. It turns out that the reflection coefficient does not vanish in
general, and that the transmitted waves suffer a lateral shift even at normal
incidence. This lateral shift can be greatlty enhanced by making the spin wave
go through an array of well separated domain walls. The outgoing spin wave will
no be attenuated by the scattering at the domain walls since the reflection
coefficient vanishes at normal incidence. This effect may be very useful to
control the spin waves in magnonic devices.",2203.11140v1
2009-05-08,Exotic Grazing Resonances in Nanowires,"We investigate electromagnetic scattering from nanoscale wires and reveal for
the first time, the emergence of a family of exotic resonances, or enhanced
fields, for source waves close to grazing incidence. These grazing resonances
can have a much higher Q factor, broader bandwidth, and are much less
susceptible to material losses than the well known surface plasmon resonances
found in metal nanowires. Contrary to surface plasmon resonances however, these
grazing resonances can be excited in both dielectric and metallic nanowires and
are insensitive to the polarization state of the incident wave. This peculiar
resonance effect originates from the excitation of long range guided surface
waves through the interplay of coherently scattered continuum modes coupled
with the azimuthal first order propagating mode of the cylindrical nanowire.
The nanowire resonance phenomenon revealed here can be utilized in broad
scientific areas, including: metamaterial designs, nanophotonic integration,
nanoantennas, and nanosensors.",0905.1357v1
2016-05-27,Quantifying resonant and near-resonant interactions in rotating turbulence,"Nonlinear triadic interactions are at the heart of our understanding of
turbulence. In flows where waves are present modes must not only be in a triad
to interact, but their frequencies must also satisfy an extra condition: the
interactions that dominate the energy transfer are expected to be resonant. We
derive equations that allow direct measurement of the actual degree of
resonance of each triad in a turbulent flow. We then apply the method to the
case of rotating turbulence, where eddies coexist with inertial waves. We show
that for a range of wave numbers, resonant and near-resonant triads are
dominant, the latter allowing a transfer of net energy towards two-dimensional
modes that would be inaccessible otherwise. The results are in good agreement
with approximations often done in theories of rotating turbulence, and with the
mechanism of parametric instability proposed to explain the development of
anisotropy in such flows. We also observe that, at least for the moderate
Rossby numbers studied here, marginally near-resonant and non-resonant triads
play a non-negligible role in the coupling of modes.",1605.08818v2
2020-10-12,One- and two-dimensional correlation spectroscopy analyses for resonant and non-resonant coherent nonlinear optical processes,"Three-color coherent anti-Stokes Raman scattering represents non-degenerate
four wave mixing process that includes both a non-resonant and resonant
processes, the contributions of which depend on how the molecular vibrational
modes are being excited by the input laser pulses. Non-degenerate four wave
mixing processes are complex and understanding these processes requires
rigorous data analytical tools, which still lack in this research field. In
this work, we introduce one- and two-dimensional intensity-intensity
correlation functions in terms of a new variable (e.g., probe pulse delay) and
new perturbation parameter (e.g., probe pulse linewidth). In particular,
diagonal projections are defined here as a tool to reduce both synchronous and
asynchronous two-dimensional correlation spectroscopy analyses down to
one-dimensional analysis, revealing valuable analytical information. Detailed
analyses using the all Gaussian coherent Raman scattering closed-form solutions
and the representative experimental data for resonant and non-resonant
processes are presented and compared. This intensity-intensity correlation
analytical tool holds a promising potential in resolving and visualizing
resonant versus non-resonant four wave mixing processes for quantitative
label-free species-specific nonlinear spectroscopy and microscopy.",2010.06017v1
2018-08-08,Observation of acoustic spin,"Unlike optical waves, acoustic waves in fluids are described by scalar
pressure fields, and therefore are considered spinless. Here, we demonstrate
experimentally the existence of spin in acoustics. In the interference of two
acoustic waves propagating perpendicularly to each other, we observed the spin
angular momentum in free space as a result of the rotation of local particle
velocity. We successfully measured the acoustic spin, and spin induced torque
acting on a lossy acoustic meta-atom that results from absorption of the spin
angular momentum. The acoustic spin is also observed in the evanescent field of
a guided mode traveling along a metamaterial waveguide. We found spin-momentum
locking in acoustic waves whose propagation direction is determined by the sign
of spin. The observed acoustic spin could open a new door in acoustics and
their applications for the control of wave propagation and particle rotation.",1808.03686v1
2016-03-17,Spin wave amplification using the spin Hall effect in permalloy/platinum bilayers,"We investigate the effect of an electrical current on the attenuation length
of a 900 nm wavelength spin-wave in a permalloy/Pt bilayer using propagating
spin-wave spectroscopy. The modification of the spin-wave relaxation rate is
linear in current density, reaching up to 14% for a current density of
2.3$\times10^{11} $A/m$^2$ in Pt. This change is attributed to the spin
transfer torque induced by the spin Hall effect and corresponds to an effective
spin Hall angle of 0.13, which is among the highest values reported so far. The
spin Hall effect thus appears as an efficient way of amplifying/attenuating
propagating spin waves.",1603.05478v1
2019-12-03,Spin-orbit torque-mediated spin-wave excitation as an alternative paradigm for femtomagnetism,"Laser-induced femtosecond demagnetization, femtomagnetism, offers a potential
route to develop faster magnetic storage devices. It is generally believed that
the traditional spin-wave theory, which is developed for thermally driven slow
demagnetization, can not explain this rapid demagnetization by design. Here we
show that this traditional spin-wave theory, once augmented by laser-induced
spin-orbit torque, provides a highly efficient paradigm for demagnetization, by
capturing low-energy spin-wave excitation that is absent in existing
mechanisms. Our paradigm is different from existing ones, but does not exclude
them. Microscopically, we find that optical spin-orbit torque generates massive
spin waves across several hundred lattice sites, collapsing the long-range
spin-spin correlation within 20 fs. Our finding does not only explain new
experiments, but also establishes an alternative paradigm for femtomagnetism.
It is expected to have far-reaching impacts on future research.",1912.01736v1
2006-04-19,Periodic and Localized Solutions of the Long Wave-Short Wave Resonance Interaction Equation,"In this paper, we investigate the (2+1) dimensional long wave-short wave
resonance interaction (LSRI) equation and show that it possess the Painlev\'e
property. We then solve the LSRI equation using Painlev\'e truncation approach
through which we are able to construct solution in terms of three arbitrary
functions. Utilizing the arbitrary functions present in the solution, we have
generated a wide class of elliptic function periodic wave solutions and
exponentially localized solutions such as dromions, multidromions, instantons,
multi-instantons and bounded solitary wave solutions.",0604039v1
2012-07-27,Physical simulation of resonant wave run-up on a beach,"Nonlinear wave run-up on the beach caused by harmonic wave maker located at
some distance from the shore line is studied experimentally. It is revealed
that under certain wave excitation frequencies a significant increase in run-up
amplification is observed. It is found that this amplification is due to the
excitation of resonant mode in the region between the shoreline and wave maker.
Frequency and magnitude of the maximum amplification are in good correlation
with the numerical calculation results represented in the paper (T.S.
Stefanakis et al. PRL (2011)). These effects are very important for
understanding the nature of rougue waves in the coastle zone.",1207.6508v1
2021-11-12,Elastic three-dimensional metaframe for selective wave filtering and polarization control,"We experimentally achieve selective wave filtering and polarization control
in a three-dimensional elastic frame embedding local resonators. By connecting
multi-resonating elements to a frame structure, a complete low-frequency,
subwavelength bandgap with strong selective filtering properties is obtained.
Theory and experiments demonstrate the metaframe capability to selectively stop
transverse waves while allowing longitudinal wave propagation, as in
'fluid-like' elasticity. This peculiar behaviour, together with the complete
bandgap structure, may open opportunities in the context of wave control,
envisaging concurrent applications for three-dimensional filters and elastic
wave polarizers.",2111.06866v2
2008-04-28,Size-selective optical forces for microspheres using evanescent wave excitation of whispering gallery modes,"We show that when a microsphere is illuminated by an evanescent wave, the
optical forces on- and off- whispering gallery mode (WGM) resonance can differ
by several orders of magnitude. Such size selective force allows one to
selectively manipulate the resonating particles, while leaving those particles
at off-resonance untouched. As WGM resonances have very high-Q's, this kind of
force could be deployed for size-selective manipulation with a very high
accuracy (~1/Q), as well as simultaneous particle-sorting according to their
size or resonant frequency.",0804.4341v1
2018-06-06,Detection of emitter-resonator coupling strength in quantum Rabi model via an auxiliary resonator,"In this paper, we propose a theoretical scheme to detect the
emitter-resonator coupling strength in the ultra-strong coupling regime in the
quantum Rabi model via introducing an auxiliary resonator. We demonstrate the
total system as a two-mode Rabi model and obtain the ground state by the
transformed rotating wave approximation, which is shown to be superior to the
usually applied rotating wave approximation. Here, the coupling strength is
detected by monitoring the average excitation number in the auxiliary resonator
and the sensitivity of the detection scheme is discussed analytically.",1806.01971v2
2017-10-12,Kinetic equation for systems with resonant captures and scatterings,"We study a Hamiltonian system of type describing a charged particle resonant
interaction with an electromagnetic wave. We consider an ensemble of particles
that repeatedly pass through the resonance with the wave, and study evolution
of the distribution function due to multiple scatterings on the resonance and
trappings (captures) into the resonance. We derive the corresponding kinetic
equation. Particular cases of this problem has been studied in our recent
papers [1, 2].",1710.04489v1
2020-03-18,New Cyclotron Resonances,"The possibilities and conditions of effective interaction, in particular
acceleration, of charged particles by the field of plane electromagnetic wave
in the presence of an external constant mag-netic field are considered. It is
shown that the well-known conditions of cyclotron resonances require
generalization. New conditions for the resonant interaction of charged
particles are for-mulated, which contain not only the strength of the external
magnetic field (as the well-known conditions of cyclotron resonances) but also
the field strength of the wave. strengths. It is shown that new resonance
conditions open up new possibilities for effective particle acceleration.",2003.08110v1
2019-10-24,Stimulated Four-Wave Mixing in Linearly Uncoupled Resonators,"We experimentally demonstrate stimulated four-wave mixing in two linearly
uncoupled integrated Si$_3$N$_4$ micro-resonators. In our structure the
resonance combs of each resonator can be tuned independently, with the energy
transfer from one resonator to the other occurring in the presence of a
nonlinear interaction. This method allows flexible and efficient on-chip
control of the nonlinear interaction, and is readily applicable to other
third-order nonlinear phenomena.",1910.11426v1
2007-02-26,Graphene-based resonant-tunneling strucures,"Resonant electronic transmission through graphene-based double barriers
(wells) is studied as a function of the incident wave vector, the widths and
heights (depths) of the barriers (wells), and the separation between them.
Resonant features in the transmission result from resonant electron states in
the wells or hole states in the barriers and strongly influence the ballistic
conductance of the structures.",0702596v1
2008-01-09,Derivation of the spatio-temporal model equations for the thermoacoustic resonator,"We derive the model equations describing the thermoacoustic resonator, that
is, an acoustical resonator containing a viscous medium inside. Previous
studies on this system have addressed this sytem in the frame of the plane-wave
approximation, we extend the previous model to by considering spatial effects
in a large aperture resonator. This model exhibits pattern formation and
localized structures scenario.",0801.1454v1
2019-03-29,Structure of resonances in a square well potential,"We study the structure of resonances as derived from the exactly solvable
Lippmann-Schwinger equation for a one-dimensional square well potential. Within
this framework, we discuss the concept of resonance form factors, and the
relation of the corresponding spatial densities to ``resonance wave
functions''.",1904.00823v1
2019-09-18,Efficient Photonic Crystal Parametric Source harnessing high-Q resonances,"A new tuning mechanism is introduced in high-Q multimode photonic crystal
resonators allowing to harness the resonant enhancement of the parametric
resonance systematically. As a consequence, ultra-efficient stimulated and
spontaneous Four Wave Mixing at continuous microWatt pumping levels are
observed, and the scaling with Q is demonstrated. Experimental results are in
perfect agreement with an analytical model without fitting parameters.",1909.08717v1
2023-11-20,"Properties of Intense Electromagnetic Ion Cyclotron Waves: Implications for Quasi-linear, Nonlinear, and Nonresonant Wave-Particle Interactions","Resonant interactions between relativistic electrons and electromagnetic ion
cyclotron (EMIC) waves provide an effective loss mechanism for this important
electron population in the outer radiation belt. The diffusive regime of
electron scattering and loss has been well incorporated into radiation belt
models within the framework of the quasi-linear diffusion theory, whereas the
nonlinear regime has been mostly studied with test particle simulations. There
is also a less investigated, nonresonant regime of electron scattering by EMIC
waves. All three regimes should be present, depending on the EMIC waves and
ambient plasma properties, but the occurrence rates of these regimes have not
been previously quantified. This study provides a statistical investigation of
the most important EMIC wave-packet characteristics for the diffusive,
nonlinear, and nonresonant regimes of electron scattering. We utilize 3 years
of Van Allen Probe observations to derive distributions of wave amplitudes,
wave-packet sizes, and rates of frequency variations within individual
wave-packets. We demonstrate that EMIC waves typically propagate as
wave-packets with $\sim 10$ wave periods each, and that $\sim 3-10$\% of such
wave-packets can reach the regime of nonlinear resonant interaction with 2 to 6
MeV electrons. We show that EMIC frequency variations within wave-packets reach
$50-100$\% of the center frequency, corresponding to a significant
high-frequency tail in their wave power spectrum. We explore the consequences
of these wave-packet characteristics for high and low energy electron
precipitation by H-band EMIC waves and for the relative importance of
quasi-linear and nonlinear regimes of wave-particle interactions.",2311.12243v1
2024-03-08,Beam-driven Electron Cyclotron Harmonic and Whistler-mode Waves as Seen in Particle-In-Cell Simulations,"Recent study has demonstrated that electron cyclotron harmonic (ECH) waves
can be excited by a low energy electron beam. Such waves propagate at
moderately oblique wave normal angles ~70. The potential role of beam-driven
ECH waves in affecting electron dynamics in Earth's plasma sheet is not known.
Using two-dimensional Darwin particle-in-cell simulations with initial electron
distributions that represent typical plasma conditions in the plasma sheet, we
explore the excitation and saturation of such beam-driven ECH waves. Both ECH
and whistler-mode waves are excited in the simulation and propagate at oblique
wave normal angles. Compared with the whistler-mode waves, ECH waves grow much
faster and have more intense saturation amplitudes. Cold, stationary electrons
are first accelerated by ECH waves through cyclotron resonance and then
accelerated in the parallel direction by both the ECH and whistler-mode waves
through Landau resonance. Beam electrons, on the other hand, are decelerated in
the parallel direction and scattered to larger pitch angles. The relaxation of
the electron beam and the continuous heating of the cold electrons contribute
to the saturation of ECH waves and suppress the excitation of whistler-mode
waves. When the ratio of plasma to electron cyclotron frequency wpe/wce
increases, the ECH wave amplitude increases while the whistler-mode wave
amplitude decreases. Our work reveals the importance of ECH and whistler-mode
waves in reshaping sub-thermal electron distributions and improves our
understanding on the potential effects of wave-particle interactions in
trapping ionospheric electron outflows and forming anisotropic (field-aligned)
electron distributions in the plasma.",2403.05675v1
2008-09-05,Avoided level crossing spectroscopy with dressed matter waves,"We devise a method for probing resonances of macroscopic matter waves in
shaken optical lattices by monitoring their response to slow parameter changes,
and show that such resonances can be disabled by particular choices of the
driving amplitude. The theoretical analysis of this scheme reveals far-reaching
analogies between dressed atoms and time-periodically forced matter waves.",0809.1032v1
2011-12-21,Properties of baryon resonances from a multichannel partial wave analysis,"Properties of nucleon and $\Delta$ resonances are derived from a multichannel
partial wave analysis. The statistical significance of pion and photo-induced
inelastic reactions off protons are studied in a multichannel partial-wave
analysis.",1112.4937v1
2013-07-10,Transmission properties of one dimensional metal and left-handed gratings,"We provide rigorous numerical calculations (using the rigorous coupled-wave
analysis) of transmission spectra of various metallic and metamaterial
one-dimensional gratings and identify plasmonic resonances responsible for
enhanced transmission. We argue that the most important mechanism which
influences the resonant transmission is the coupling of incident
electromagnetic wave with two plasmonic waves: lengthwise plasmons, which
propagates along the grating, and crosswise plasmons excited in air gaps.",1307.2711v1
2013-09-21,Counting of discrete Rossby/drift wave resonant triads (again),"The purpose of our earlier note (arXiv:1309.0405 [physics.flu-dyn]) was to
remove the confusion over counting of resonant wave triads for Rossby and drift
waves in the context of the Charney-Hasegawa-Mima equation. A comment by
Kartashov and Kartashova (arXiv:1309.0992v1 [physics.flu-dyn]) on that note has
further confused the situation. The present note aims to remove this
obfuscation.",1309.5513v1
2015-10-19,Photonic crystal with left-handed components,"We show that the periodic array of left-handed cylinders possesses a rich
spectrum of guided modes when the negative permeability of cylinders equals
exactly to minus value of permeability of embedding media. These resonances
strongly influences propagation of electromagnetic waves through photonic
structures made from left-handed materials. A series of Fano resonances excited
by incident wave destroys the band frequency spectrum of square array of
left-handed cylinders and increases considerably the absorption of transmitted
waves.",1510.05362v1
2020-06-03,Wave Support Theorem and Inverse Resonant Uniqueness on the Line,"In the paper, we experimentally study the inverse problem with the resonant
scattering determinant. We analyze the structure of characteristics of
perturbed linear waves. Assuming there is the common part of potential
perturbation propagating along the same strips, we estimate the common part of
the perturbed wave, and its Fourier transform.
  We deduce the partial inverse uniqueness from the Nevanlinna type of
representation theorem.",2006.02465v1
2014-08-21,Neutron-Proton Scattering in the Context of the $d^*$(2380) Resonance,"New data on quasifree polarized neutron-proton scattering, in the region of
the recently observed $d^*$ resonance structure, have been obtained by
exclusive and kinematically complete high-statistics measurements with WASA at
COSY. This paper details the determination of the beam polarization, checks of
the quasifree character of the scattering process, on all obtained $A_y$
angular distributions and on the new partial-wave analysis, which includes the
new data producing a resonance pole in the $^3D_3$-$^3G_3$ coupled partial
waves at ($2380\pm10 - i40\pm5$) MeV -- in accordance with the $d^*$ dibaryon
resonance hypothesis. The effect of the new partial-wave solution on the
description of total and differential cross section data as well as specific
combinations of spin-correlation and spin-transfer observables available from
COSY-ANKE measurements at $T_d$ = 2.27 GeV is discussed.",1408.4928v1
1998-05-12,Resonant Thickening of Disks by Small Satellite Galaxies,"We study the vertical heating and thickening of galaxy disks due to accretion
of small satellites. Our simulations are restricted to axial symmetry, which
largely eliminates numerical evolution of the target galaxy but requires the
trajectory of the satellite to be along the symmetry axis of the target. We
find that direct heating of disk stars by the satellite is not important
because the satellite's gravitational perturbation has little power at
frequencies resonant with the vertical stellar orbits. The satellite does
little damage to the disk until its decaying orbit resonantly excites
large-scale disk bending waves. Bending waves can damp through dynamical
friction from the halo or internal wave-particle resonances; we find that
wave-particle resonances dominate the damping. The principal vertical heating
mechanism is therefore dissipation of bending waves at resonances with stellar
orbits in the disk. Energy can thus be deposited some distance from the point
of impact of the satellite. The net heating from a tightly bound satellite can
be substantial, but satellites that are tidally disrupted before they are able
to excite bending waves do not thicken the disk.",9805145v1
2004-11-19,Particle acceleration through the resonance of high magnetic field and high frequency electromagnetic wave,"We propose a new particle acceleration mechanism. Electron can be accelerated
to relativistic energy within a few electromagnetic wave cycles through the
mechanism which is named electromagnetic and magnetic field resonance
acceleration (EMRA). We find that the electron acceleration depends not only on
the electromagnetic wave intensity, but also on the ratio between electron
Larmor frequency and electromagnetic wave frequency. As the ratio approaches to
unity, a clear resonance peak is observed, corresponding to the EMRA. Near the
resonance regime, the strong magnetic fields still affect the electron
acceleration dramatically. We derive an approximate analytical solution of the
relativistic electron energy in adiabatic limit, which provides a full
understanding of this phenomenon. In typical parameters of pulsar
magnetospheres, the mechanism allows particles to increase their energies
through the resonance of high magnetic field and high frequency electromagnetic
wave in each electromagnetic wave period. The energy spectra of the accelerated
particles exhibit the synchrotron radiation behavior. These can help to
understand the remaining emission of high energy electron from radio pulsar
within supernova remnant. The other potential application of our theory in fast
ignition scheme of inertial confinement fusion is also discussed.",0411183v1
2014-02-06,Saturn Ring Seismology: Looking Beyond First Order Resonances,"Some wave features found in the C-ring of Saturn appear to be excited by
resonances with normal mode oscillations of the planet. The waves are found at
locations in the rings where the ratio of orbital to oscillation frequencies is
given by m : m+1 where m is a small integer. I suggest here that it is
plausible that ring waves may also be launched at second order resonances,
where the frequency ratio would be m : m+2. Indeed, otherwise unassociated wave
features are found at such locations in the C-ring. If confirmed the
association of planetary modes with additional C-ring wave features would
measure additional oscillation frequencies of Saturn and improve the utility of
the waves for constraining the internal structure of the planet. Second-order
resonances in general do not lie near first order ring resonance locations and
thus are not the explanation for the apparent frequency splitting of modes.",1402.1415v1
2021-05-12,On application of stochastic differential equations for simulation of nonlinear wave-particle resonant interactions,"Long-term simulations of energetic electron fluxes in many space plasma
systems require accounting for two groups of processes with well separated
time-scales: microphysics of electron resonant scattering by electromagnetic
waves and electron adiabatic heating/transport by mesoscale plasma flows.
Examples of such systems are Earth's radiation belts and Earth's bow shock,
where ion-scale plasma injections and cross-shock electric fields determine the
general electron energization, whereas electron scattering by waves relax
anisotropy of electron distributions and produces small populations of
high-energy electrons. The applicability of stochastic differential equations
is a promising approach for including effects of resonant wave-particle
interaction into codes of electron tracing in global models. This study is
devoted to test of such equations for systems with nondiffusive wave-particle
interactions, i.e. systems with nonlinear effects of phase trapping and
bunching. We consider electron resonances with intense electrostatic
whistler-mode waves often observed in the Earth's radiation belts. We
demonstrate that nonlinear resonant effects can be described by stochastic
differential equations with the non-Gaussian probability distribution of random
variations of electron energies.",2105.05819v1
2024-02-07,Triadic Resonance in Columnar Vortices,"Employing a poloidal-toroidal projection technique, a multi-scale analysis of
resonant wave triads in columnar vortices is performed to obtain the governing
equations of the triadically coupled wave amplitudes. For inviscid flows, we
establish that resonance between neutral, smooth waves is conservative, and the
temporal evolution of wave amplitudes is either bounded or explosively unstable
based on the signs of the triad's interaction coefficients. Assessing the onset
of weakly nonlinear instabilities through the pseudoenergy criterion introduced
by Cairns (1979, J. Fluid Mech., vol. 92), we use the large-axial-wavenumber
asymptotic approach by Le Dizes and Lacaze (2005, J. Fluid Mech., vol. 542) to
evaluate each triad member's pseudoenergy and argue against the possibility of
explosive conservative three-wave resonance involving only regular Kelvin
waves. Additionally, extending our investigation to specific vortices, such as
the Lamb-Oseen vortex and the Batchelor vortex, we find that triadic resonance
among their neutral modes consistently results in bounded behaviour.",2402.05287v1
2005-07-29,Anisotropic interactions of a single spin and dark-spin spectroscopy in diamond,"The nitrogen-vacancy (N-V) center in diamond is a promising atomic-scale
system for solid-state quantum information processing. Its spin-dependent
photoluminescence has enabled sensitive measurements on single N-V centers,
such as: electron spin resonance, Rabi oscillations, single-shot spin readout
and two-qubit operations with a nearby 13C nuclear spin. Furthermore, room
temperature spin coherence times as long as 58 microseconds have been reported
for N-V center ensembles. Here, we have developed an angle-resolved
magneto-photoluminescence microscopy apparatus to investigate the anisotropic
electron spin interactions of single N-V centers at room temperature. We
observe negative peaks in the photoluminescence as a function of both magnetic
field magnitude and angle that are explained by coherent spin precession and
anisotropic relaxation at spin level anti-crossings. In addition, precise field
alignment unmasks the resonant coupling to neighboring dark nitrogen spins that
are not otherwise detected by photoluminescence. The latter results demonstrate
a means of investigating small numbers of dark spins via a single bright spin
under ambient conditions.",0507706v1
2005-08-03,Spin filter using a semiconductor quantum ring side-coupled to a quantum wire,"We introduce a new spin filter based on spin-resolved Fano resonances due to
spin-split levels in a quantum ring (QR) side-coupled to a quantum wire (QW).
Spin-orbit coupling inside the QR, together with external magnetic fields,
induces spin splitting, and the Fano resonances due to the spin-split levels
result in perfect or considerable suppression of the transport of either spin
direction. Using the numerical renormalization group method, we find that the
Coulomb interaction in the QR enhances the spin filter operation by widening
the separation between dips in conductances for different spins and by allowing
perfect blocking for one spin direction and perfect transmission for the other.
The spin-filter effect persists as long as the temperature is less than the
broadening of QR levels due to the QW-QR coupling. We discuss realistic
conditions for the QR-based spin filter and its advantages to other similar
devices.",0508099v1
2021-08-02,Coherent spin-spin coupling mediated by virtual microwave photons,"We report the coherent coupling of two electron spins at a distance via
virtual microwave photons. Each spin is trapped in a silicon double quantum dot
at either end of a superconducting resonator, achieving spin-photon couplings
up to around $g_s/2\pi = 40 \ \text{MHz}$. As the two spins are brought into
resonance with each other, but detuned from the photons, an avoided crossing
larger than the spin linewidths is observed with an exchange splitting around
$2J/2\pi = 20 \ \text{MHz}$. In addition, photon-number states are resolved
from the shift $2\chi_s/2\pi = -13 \ \text{MHz}$ that they induce on the spin
frequency. These observations demonstrate that we reach the strong dispersive
regime of circuit quantum electrodynamics with spins. Achieving spin-spin
coupling without real photons is essential to long-range two-qubit gates
between spin qubits and scalable networks of spin qubits on a chip.",2108.01206v2
2012-11-29,"The $p(γ,K^+)Λ$ reaction: consistent high-spin interactions and Bayesian inference of its resonance content","A Bayesian analysis of the world's $p(\gamma,K^+)\Lambda$ data is presented.
We adopt a Regge-plus-resonance framework featuring consistent interactions for
nucleon resonances up to spin $J = 5/2$. The power of the momentum dependence
of the consistent interaction structure rises with the spin of the resonance.
This leads to unphysical structures in the energy dependence of the computed
cross sections when the short-distance physics is cut off with standard
hadronic form factors. A plausible, spin-dependent modification of the hadronic
form factor is proposed which suppresses the unphysical artifacts. Next, we
evaluate all possible combinations of 11 candidate resonances. The best model
is selected from the 2048 model variants by calculating the Bayesian evidence
values against the world's $p(\gamma,K^+)\Lambda$ data. From the proposed
selection of 11 resonances, we find that the following nucleon resonances have
the highest probability of contributing to the reaction: $S_{11}(1535)$,
$S_{11}(1650)$, $F_{15}(1680)$, $P_{13}(1720)$, $D_{13}(1900)$, $P_{13}(1900)$,
$P_{11}(1900)$, and $F_{15}(2000)$.",1211.6896v2
2012-12-29,Multi-resonance orbital model of HF QPOs,"Using known frequencies of the twin peak high-frequency quasiperiodic
oscillations (HF QPOs) and known mass M of the central black hole, the
black-hole dimensionless spin a can be determined assuming a concrete version
of the resonance model. However, large range of observationally limited values
of the black hole mass implies a low precision of the spin estimates. We
discuss the possibility of higher precision of the black hole spin measurements
in the framework of multi-resonance model inspired by observations of more than
two HF QPOs in some black hole sources. We determine the spin and mass
dependence of the twin peak frequencies with a general rational ratio n:m
assuming a non-linear resonance of oscillations with the epicyclic and
Keplerian frequencies or their combinations. In the multi-resonant model, the
twin peak resonances are combined properly to give the observed frequency set.
We focus on the special case of duplex frequencies, when the top, bottom, or
mixed frequency is common at two different radii where the resonances occur
giving triple frequency sets.",1212.6668v1
2019-02-14,Breakdown of the Hebel-Slichter effect in superconducting graphene due to the emergence of Yu-Shiba-Rusinov states at magnetic resonant scatterers,"Employing analytical methods and quantum transport simulations we investigate
the relaxation of quasiparticle spins in graphene proximitized by an $s$-wave
superconductor in the presence of resonant magnetic and spin-orbit active
impurities. Off resonance, the relaxation increases with decreasing temperature
when electrons scatter off magnetic impurities---the Hebel-Slichter
effect---and decreases when impurities have spin-orbit coupling. This distinct
temperature~dependence (not present in the normal state) uniquely discriminates
between the two scattering mechanisms. However, we show that the Hebel-Slichter
picture breaks down at resonances. The emergence of Yu-Shiba-Rusinov bound
states within the superconducting gap redistributes the spectral weight away
from magnetic resonances. The result is opposite to the Hebel-Slichter
expectation: the spin relaxation decreases with decreasing temperature. Our
findings hold for generic $s$-wave superconductors with resonant magnetic
impurities, but also, as we show, for resonant magnetic Josephson junctions.",1902.05474v2
2019-03-20,Limits of flexural wave absorption by open lossy resonators: reflection and transmission problems,"The limits of flexural wave absorption by open lossy resonators are
analytically and numerically reported in this work for both the reflection and
transmission problems. An experimental validation for the reflection problem is
presented. The reflection and transmission of flexural waves in 1D resonant
thin beams are analyzed by means of the transfer matrix method. The hypotheses,
on which the analytical model relies, are validated by experimental results.
The open lossy resonator, consisting of a finite length beam thinner than the
main beam, presents both energy leakage due to the aperture of the resonators
to the main beam and inherent losses due to the viscoelastic damping. Wave
absorption is found to be limited by the balance between the energy leakage and
the inherent losses of the open lossy resonator. The perfect compensation of
these two elements is known as the critical coupling condition and can be
easily tuned by the geometry of the resonator. On the one hand, the scattering
in the reflection problem is represented by the reflection coefficient. A
single symmetry of the resonance is used to obtain the critical coupling
condition. Therefore the perfect absorption can be obtained in this case. On
the other hand, the transmission problem is represented by two eigenvalues of
the scattering matrix, representing the symmetric and anti-symmetric parts of
the full scattering problem. In the geometry analyzed in this work, only one
kind of symmetry can be critically coupled, and therefore, the maximal
absorption in the transmission problem is limited to 0.5. The results shown in
this work pave the way to the design of resonators for efficient flexural wave
absorption.",1903.08522v1
2017-10-05,Vector rogue waves on a double-plane wave background,"We study rogue wave excitation dynamics on a double-plane wave background
through deriving rogue wave solution on the background. The results indicate
that rogue wave still can be excited successfully from resonant perturbations
with the two plane wave backgrounds. The obtained vector rogue wave can be
decomposed to two rogue waves located on the two backgrounds separately. This
enables us to investigate the superpositions of two of the three well-known
fundamental rogue wave patterns, mainly including eye-shaped, anti-eye-shaped,
and four-petaled one. The explicit conditions for different possible
superpositions are clarified by a phase diagram for rogue wave pattern on each
plane wave background. The detail analysis indicate that the rogue wave admits
many different profiles, in contrast to the ones reported before. The studies
can be extended directly to investigate other localized waves on double-plane
wave background and even more plane waves involved cases.",1710.02123v1
2005-07-01,Spin-orbit coupling and spin transport,"Recent achievements in semiconductor spintronics are discussed. Special
attention is paid to spin-orbit interaction, coupling of electron spins to
external electric fields, and spin transport in media with spin-orbit coupling,
including the mechanisms of spin-Hall effect. Importance of spin-transport
parameters at spin-precession wave vector $k_{\rm so}$ is emphasized, and
existence of an universal relation between spin currents and spin accumulation
at the spatial scale of $\ell_{\rm so}\approx k_{\rm so}^{-1}$ is conjectured.",0507007v2
2006-05-30,Electric Dipole Induced Spin Resonance in Disordered Semiconductors,"One of the hallmarks of spintronics is the control of magnetic moments by
electric fields enabled by strong spin-orbit interaction (SOI) in
semiconductors. A powerful way of manipulating spins in such structures is
electric dipole induced spin resonance (EDSR), where the radio-frequency fields
driving the spins are electric, and not magnetic like in standard paramagnetic
resonance. Here, we present a theoretical study of EDSR for a two-dimensional
electron gas in the presence of disorder where random impurities not only
determine the electric resistance but also the spin dynamics via SOI.
Considering a specific geometry with the electric and magnetic fields parallel
and in-plane, we show that the magnetization develops an out-of-plane component
at resonance which survives the presence of disorder. We also discuss the spin
Hall current generated by EDSR. These results are derived in a diagrammatic
approach with the dominant effects coming from the spin vertex correction, and
the optimal parameter regime for observation is identified.",0605735v1
2003-03-03,Higher spin hadrons as relativistic fields,"I discuss the problem of consistent interactions of higher-spin fields and
its relevance to resonance physics.",0303005v1
2020-09-09,Superconductivity-enhanced spin pumping: Role of Andreev resonances,"We describe a simple hybrid superconductor$|$ferromagnetic-insulator
structure manifesting spin-resolved Andreev bound states in which dynamic
magnetization is employed to probe spin related physics. We show that, at low
bias and below $T_c$, the transfer of spin angular momentum pumped by an
externally driven ferromagnetic insulator is greatly affected by the formation
of spin-resolved Andreev bound states. Our results indicate that these bound
states capture the essential physics of condensate-facilitated spin flow. For
finite thicknesses of the superconducting layer, comparable to the coherence
length, resonant Andreev bound states render highly transmitting subgap spin
transport channels. We point out that the resonant enhancement of the subgap
transport channels establishes a prototype Fabry-P\'erot resonator for spin
pumping.",2009.04423v4
2019-10-26,Spin-rotation coupling in p-wave Feshbach resonances,"We report evidence for spin-rotation coupling in $p$-wave Feshbach resonances
in an ultracold mixture of fermionic $^6$Li and bosonic $^{133}$Cs lifting the
commonly observed degeneracy of states with equal absolute value of
orbital-angular-momentum projection on the external magnetic field. By
employing magnetic field dependent atom-loss spectroscopy we find triplet
structures in $p$-wave resonances. Comparison with coupled-channel
calculations, including contributions from both spin-spin and spin-rotation
interactions, yields a spin-rotation coupling parameter
$|\gamma|=0.566(50)\times10^{-3}$. Our findings highlight the potential of
Feshbach resonances in revealing subtle molecular couplings and providing
precise information on electronic and nuclear wavefunctions, especially at
short internuclear distance. The existence of a non-negligible spin-rotation
splitting may have consequences for future classifications of $p$-wave
superfluid phases in spin-polarized fermions.",1910.12011v2
2024-02-06,Loss and decoherence in superconducting circuits on silicon: Insights from electron spin resonance,"Solid-state devices used for quantum computation and quantum sensing
applications are adversely affected by loss and noise caused by spurious,
charged two-level systems (TLS) and stray paramagnetic spins. These two sources
of noise are interconnected, exacerbating the impact on circuit performance. We
use an on-chip electron spin resonance (ESR) technique, with niobium nitride
(NbN) superconducting resonators, to study surface spins on silicon and the
effect of post-fabrication surface treatments. We identify two distinct spin
species that are characterized by different spin-relaxation times and respond
selectively to various surface treatments (annealing and hydrofluoric acid).
Only one of the two spin species has a significant impact on the TLS-limited
resonator quality factor at low-power (near single-photon) excitation. We
observe a 3-to-5-fold reduction in the total density of spins after surface
treatments, and demonstrate the efficacy of ESR spectroscopy in developing
strategies to mitigate loss and decoherence in quantum systems.",2402.03889v1
2006-01-07,Gravitomagnetic resonant excitation of Rossby modes in coalescing neutron star binaries,"In coalescing neutron star binaries, r-modes in one of the stars can be
resonantly excited by the gravitomagnetic tidal field of its companion. This
post-Newtonian gravitomagnetic driving of these modes dominates over the
Newtonian tidal driving previously computed by Ho and Lai. To leading order in
the tidal expansion parameter R/r (where R is the radius of the neutron star
and r is the orbital separation), only the l=2, |m|= 1 and |m| = 2 r-modes are
excited. The tidal work done on the star through this driving has an effect on
the evolution of the inspiral and on the phasing of the emitted gravitational
wave signal. For a neutron star of mass M, radius R, spin frequency f_spin,
modeled as a Gamma =2 polytrope, with a companion also of mass M, the
gravitational wave phase shift for the m=2 mode is
(0.1radians)(R/10km)^4(M/1.4M_sun)^{-10/3}(f_spin/100Hz)^{2/3} for optimal spin
orientation. For canonical neutron star parameters this phase shift will likely
not be detectable by gravitational wave detectors such as LIGO, but if the
neutron star radius is larger it may be detectable if the signal-to-noise ratio
is moderately large. For neutron star - black hole binaries, the effect is
smaller; the phase shift scales as companion mass to the -4/3 power for large
companion masses. The net energy transfer from the orbit into the star is
negative corresponding to a slowing down of the inspiral. This occurs because
the interaction reduces the spin of the star, and occurs only for modes which
satisfy the Chandrasekhar-Friedman-Schutz instability criterion.",0601029v2
2011-05-05,Electronic structure of the substitutional vacancy in graphene: Density-functional and Green's function studies,"We study the electronic structure of graphene with a single substitutional
vacancy using a combination of the density-functional, tight-binding, and
impurity Green's function approaches. Density functional studies are performed
with the all-electron spin-polarized linear augmented plane wave (LAPW) method.
The three $sp^2 \sigma$ dangling bonds adjacent to the vacancy introduce
localized states (V$\sigma$) in the mid-gap region, which split due to the
crystal field and a Jahn-Teller distortion, while the $p_z \pi$ states
introduce a sharp resonance state (V$\pi$) in the band structure. For a planar
structure, symmetry strictly forbids hybridization between the $\sigma$ and the
$\pi$ states, so that these bands are clearly identifiable in the calculated
band structure. As for the magnetic moment of the vacancy, the Hund's-rule
coupling aligns the spins of the four localized V$\sigma_1 \uparrow
\downarrow$, V$\sigma_2 \uparrow $, and the V$\pi \uparrow$ electrons resulting
in a S=1 state, with a magnetic moment of $2 \mu_B$, which is reduced by about
$0.3 \mu_B$ due to the anti-ferromagnetic spin-polarization of the $\pi$ band
itinerant states in the vicinity of the vacancy. This results in the net
magnetic moment of $1.7 \mu_B$. Using the Lippmann-Schwinger equation, we
reproduce the well-known $\sim 1/r$ decay of the localized V$\pi$ wave function
with distance and in addition find an interference term coming from the two
Dirac points, previously unnoticed in the literature. The long-range nature of
the V$\pi$ wave function is a unique feature of the graphene vacancy and we
suggest that this may be one of the reasons for the widely varying relaxed
structures and magnetic moments reported from the supercell band calculations
in the literature.",1105.1129v4
2015-01-24,Detecting gravitational waves from mountains on neutron stars in the Advanced Detector Era,"Rapidly rotating Neutron Stars (NSs) in Low Mass X-ray Binaries (LMXBs) are
thought to be interesting sources of Gravitational Waves (GWs) for current and
next generation ground based detectors, such as Advanced LIGO and the Einstein
Telescope. The main reason is that many of the NS in these systems appear to be
spinning well below their Keplerian breakup frequency, and it has been
suggested that torques associated with GW emission may be setting the observed
spin period. This assumption has been used extensively in the literature to
assess the strength of the likely gravitational wave signal. There is now,
however, a significant amount of theoretical and observation work that suggests
that this may not be the case, and that GW emission is unlikely to be setting
the spin equilibrium period in many systems. In this paper we take a different
starting point and predict the GW signal strength for two physical mechanisms
that are likely to be at work in LMXBs: crustal mountains due to thermal
asymmetries and magnetically confined mountains. We find that thermal crustal
mountains in transient LMXBs are unlikely to lead to detectable GW emission,
while persistent systems are good candidates for detection by Advanced LIGO and
by the Einstein Telescope. Detection prospects are pessimistic for the magnetic
mountain case, unless the NS has a buried magnetic field of $B\approx 10^{12}$
G, well above the typically inferred exterior dipole fields of these objects.
Nevertheless, if a system were to be detected by a GW observatory, cyclotron
resonant scattering features in the X-ray emission could be used to distinguish
between the two different scenarios.",1501.06039v1
2023-07-29,Extreme mass-ratio inspirals into black holes surrounded by scalar clouds,"We study extreme mass-ratio binary systems in which a stellar mass compact
object spirals into a supermassive black hole surrounded by a scalar cloud.
Scalar clouds can form through superradiant instabilities of massive scalar
fields around spinning black holes and can also serve as a proxy for dark
matter halos. Our framework is fully relativistic and assumes that the impact
of the cloud on the geometry can be treated perturbatively. As a proof of
concept, here we consider a point particle in circular, equatorial motion
around a non-spinning black hole surrounded either by a spherically symmetric
or a dipolar non-axisymmetric scalar cloud, but the framework can in principle
be generalized to generic black hole spins and scalar cloud geometries. We
compute the leading-order power lost by the point particle due to scalar
radiation and show that, in some regimes, it can dominate over
gravitational-wave emission. We confirm the presence of striking signatures due
to the presence of a scalar cloud that had been predicted using Newtonian
approximations, such as resonances that can give rise to sinking and floating
orbits, as well as ""sharp features"" in the power lost by the particle at given
orbital radii. Finally, for a spherically symmetric scalar cloud, we also
compute the leading-order corrections to the black-hole geometry and to the
gravitational-wave energy flux, focusing only on axial metric perturbations for
the latter. We find that, for non-compact clouds, the corrections to the
(axial) gravitational-wave fluxes at high frequencies can be understood in
terms of a gravitational-redshift effect, in agreement with previous works.",2307.16093v3
2016-05-13,Investigation of resonances in gravity-capillary wave turbulence,"We report experimental results on nonlinear wave coupling in surface wave
turbulence on water at scales close to the crossover between surface gravity
waves and capillary waves. We study 3-wave correlations either in the frequency
domain or in wavevector domain. We observe that in a weakly nonlinear regime,
the dominant nonlinear interactions correspond to waves that are collinear or
close to collinear. Although the resonant coupling of pure gravity waves is
supposed to involve 4 waves, at the capillary crossover we observe a nonlocal
coupling between a gravity wave and 2 capillary waves. Furthermore nonlinear
spectral spreading permits 3-gravity wave coupling. These observations raise
the question of the relevance of these processes in the oceanographic context
and in particular the range of frequencies of gravity waves that may be
impacted.",1605.04091v1
2009-12-28,Resonant Interactions Between Protons and Oblique Alfvén/Ion-Cyclotron Waves,"Resonant interactions between ions and Alfv\'en/ion-cyclotron (A/IC) waves
may play an important role in the heating and acceleration of the fast solar
wind. Although such interactions have been studied extensively for ""parallel""
waves, whose wave vectors ${\bf k}$ are aligned with the background magnetic
field ${\bf B}_0$, much less is known about interactions between ions and
oblique A/IC waves, for which the angle $\theta$ between ${\bf k}$ and ${\bf
B}_0$ is nonzero. In this paper, we present new numerical results on resonant
cyclotron interactions between protons and oblique A/IC waves in collisionless
low-beta plasmas such as the solar corona. We find that if some mechanism
generates oblique high-frequency A/IC waves, then these waves initially modify
the proton distribution function in such a way that it becomes unstable to
parallel waves. Parallel waves are then amplified to the point that they
dominate the wave energy at the large parallel wave numbers at which the waves
resonate with the particles. Pitch-angle scattering by these waves then causes
the plasma to evolve towards a state in which the proton distribution is
constant along a particular set of nested ""scattering surfaces"" in velocity
space, whose shapes have been calculated previously. As the distribution
function approaches this state, the imaginary part of the frequency of parallel
A/IC waves drops continuously towards zero, but oblique waves continue to
undergo cyclotron damping while simultaneously causing protons to diffuse
across these kinetic shells to higher energies. We conclude that oblique A/IC
waves can be more effective at heating protons than parallel A/IC waves,
because for oblique waves the plasma does not relax towards a state in which
proton damping of oblique A/IC waves ceases.",0912.5184v1
2007-11-02,Spin-torque driven ferromagnetic resonance of Co/Ni synthetic layers in spin valves,"Spin-torque driven ferromagnetic resonance (ST-FMR) is used to study thin
Co/Ni synthetic layers with perpendicular anisotropy confined in spin-valve
based nanojunctions. Field swept ST-FMR measurements were conducted with a
magnetic field applied perpendicular to the layer surface. The resonance lines
were measured under low amplitude rf excitation, from 1 to 20 GHz. These
results are compared with those obtained using conventional rf field driven FMR
on extended films with the same Co/Ni layer structure. The layers confined in
spin valves have a lower resonance field, a narrower resonance linewidth and
approximately the same linewidth vs frequency slope, implying the same damping
parameter. The critical current for magnetic excitations is determined from
measurements of the resonance linewidth vs dc current and is in accord with the
one determined from I-V measurements.",0711.0405v2
2010-09-19,Effect of spin transfer torque on the magnetic domain wall ferromagnetic resonance frequency in the nanowires,"We investigate the influence of the domain wall ferromagnetic resonance
frequency on the spin transfer torque in a ferromagnetic nanowire. By employing
micromagnetic simulations with the spin transfer torque, we find that the
domain wall resonance frequency decreases with increasing spin polarized
current density, when there is no change in the resonance frequency of the
domain itself. Surprisingly, the variation of the resonance frequency is
remarkable (> 1.6 GHz) with the spin transfer torque even though the domain
wall is pinned. Since the presented domain wall ferromagnetic resonance study
has been performed for the pinned domain wall, the contributions of extrinsic
defects are excluded. It is strong advantages of the present study, since the
effects of extrinsic pinning sites are inevitable in the imaging or transport
measurements.",1009.3618v1
2012-02-10,Charmed and strange baryon resonances with heavy-quark spin symmetry,"We study charmed and strange baryon resonances that are generated dynamically
by a unitary baryon-meson coupled-channel model which incorporates heavy-quark
spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa
chiral Lagrangian to SU(8) spin-flavor symmetry plus a suitable symmetry
breaking. The model produces resonances with negative parity from s-wave
interaction of pseudoscalar and vector mesons with $1/2^+$ and $3/2^+$ baryons.
Resonances in all the isospin, spin, and strange sectors with one, two, and
three charm units are studied. Our results are compared with experimental data
from several facilities, such as the CLEO, Belle or BaBar Collaborations, as
well as with other theoretical models. Some of our dynamically generated states
can be readily assigned to resonances found experimentally, while others do not
have a straightforward identification and require the compilation of more data
and also a refinement of the model. In particular, we identify the
$\Xi_c(2790)$ and $\Xi_c(2815)$ resonances as possible candidates for a
heavy-quark spin symmetry doublet.",1202.2239v2
2017-05-05,Multi-frequency Spin Manipulation Using Rapidly Tunable Superconducting Coplanar Waveguide Microresonators,"In this work, we demonstrate the use of frequency-tunable superconducting
NbTiN coplanar waveguide microresonators for multi-frequency pulsed electron
spin resonance (ESR) experiments. By applying a bias current to the center pin,
the resonance frequency ($\sim$7.6 GHz) can be continuously tuned by as much as
95 MHz in 270 ns without a change in the quality factor of 3000 at 2K. We
demonstrate the ESR performance of our resonators by measuring donor spin
ensembles in silicon and show that adiabatic pulses can be used to overcome
magnetic field inhomogeneities and microwave power limitations due to the
applied bias current. We take advantage of the rapid tunability of these
resonators to manipulate both phosphorus and arsenic spins in a single pulse
sequence, demonstrating pulsed double electron-electron resonance (DEER). Our
NbTiN resonator design is useful for multi-frequency pulsed ESR and should also
have applications in experiments where spin ensembles are used as quantum
memories.",1705.02413v2
2023-11-27,Near-resonant nuclear spin detection with high-frequency mechanical resonators,"Mechanical resonators operating in the high-frequency regime have become a
versatile platform for fundamental and applied quantum research. Their
exceptional properties, such as low mass and high quality factor, make them
also very appealing for force sensing experiments. In this Letter, we propose a
method for detecting and ultimately controlling nuclear spins by directly
coupling them to high-frequency resonators via a magnetic field gradient.
Dynamical backaction between the sensor and an ensemble of nuclear spins
produces a shift in the sensor's resonance frequency, which can be measured to
probe the spin ensemble. Based on analytical as well as numerical results, we
predict that the method will allow nanoscale magnetic resonance imaging with a
range of realistic devices. At the same time, this interaction paves the way
for new manipulation techniques, similar to those employed in cavity
optomechanics, enriching both the sensor's and the spin ensemble's features.",2311.16273v1
2001-04-16,Enhancement of Nuclear Spin Superradiance by Electron Resonator,"Superradiance of nuclear spins is considered, when the nuclei interact via
hyperfine forces with electrons of a ferromagnet. The consideration is based on
a microscopic model. If the sample, coupled with a resonant electric circuit,
possesses electronic magnetization, then the electron subsystem plays the role
of an additional effective resonator, by enhancing the coupling between nuclear
spins and the resonant circuit. Radiation power can be increased by three
orders, while the radiation time of a superradiance burst can become three
times shorter. In the presence of dynamic nuclear polarization, the regime of
pulsing superradiance can occur.",0104276v1
2003-09-12,Measurement of a Mixed Spin Channel Feshbach Resonance in Rubidium 87,"We report on the observation of a mixed spin channel Feshbach resonance at
the low magnetic field value of (9.09 +/- 0.01) G for a mixture of |2,-1> and
|1,+1> states in 87Rb. This mixture is important for applications of
multi-component BECs of 87Rb, e.g. in spin mixture physics and for quantum
entanglement. Values for position, height and width of the resonance are
reported and compared to a recent theoretical calculation of this resonance.",0309318v3
2004-01-14,The spin resonance and high frequency optical properties of the cuprates,"We argue that recently observed superconductivity-induced blue shift of the
plasma frequency $\delta \omega_{pl}$ in $Bi_2Sr_2CaCu_2O_{8+\delta}$ is
related to the change in the integrated dynamical structure factor associated
with the development of the spin resonance below $T_c$. We show that the
magnitude of $\delta \omega_{pl}$ is consistent with the small integrated
spectral weight of the resonance, and its temperature dependences closely
follow that of the spin resonance peak.",0401241v1
2005-03-17,Raman resonance in spin S two-leg ladder systems,"We argue that the Raman intensity in a spin S two-leg spin-ladder has a
pseudo-resonance peak, whose width is very small at large S. The
pseudo-resonance originates from the existence of a local minimum in the magnon
excitation spectrum, and is located slightly below twice the magnon energy at
the minimum. The physics behind the peak is similar to the excitonic scenario
for the neutron and Raman resonances in a d-wave superconductor.",0503453v1
2005-11-22,Spatial Imaging and Mechanical Control of Spin Coherence in Strained GaAs Epilayers,"The effect of uniaxial tensile strain on spin coherence in n-type GaAs
epilayers is probed using time-resolved Kerr rotation, photoluminescence, and
optically-detected nuclear magnetic resonance spectroscopies. The bandgap,
electron spin lifetime, electron g-factor, and nuclear quadrupole splitting are
simultaneously imaged over millimeter scale areas of the epilayers for
continuously varying values of strain. All-optical nuclear magnetic resonance
techniques allow access to the strain induced nuclear quadrupolar resonance
splitting in field regimes not easily addressable using conventional
optically-detected nuclear magnetic resonance.",0511562v1
2006-01-08,Resonant control of spin dynamics in ultracold quantum gases by microwave dressing,"We study experimentally interaction-driven spin oscillations in optical
lattices in the presence of an off-resonant microwave field. We show that the
energy shift induced by this microwave field can be used to control the spin
oscillations by tuning the system either into resonance to achieve near-unity
contrast or far away from resonance to suppress the oscillations. Finally, we
propose a scheme based on this technique to create a flat sample with either
singly- or doubly-occupied sites, starting from an inhomogeneous Mott
insulator, where singly- and doubly-occupied sites coexist.",0601151v1
1996-06-27,Heavy Baryon Chiral Perturbation Theory and the Spin 3/2 Delta Resonances,"Heavy baryon chiral perturbation theory is briefly reviewed, paying
particular attention to the role of the spin 3/2 delta resonances. The concept
of resonance saturation for the baryonic sector is critically discussed.
Starting from a relativistic formulation of the pion-nucleon-delta system, the
heavy baryon chiral lagrangian including spin 3/2 resonances is constructed by
means of a 1/m-expansion. The effective theory obtained admits a systematic
expansion in terms of soft momenta, the pion mass $M_\pi$ and the delta-nucleon
mass difference $\Delta$.",9606455v1
2000-12-05,Nucleon resonances in polarized omega photoproduction,"The role of the nucleon resonances ($N^*$) in $\omega$ photoproduction is
investigated by using the resonance parameters predicted by Capstick and
Roberts. The contributions from the nucleon resonances are found to be
significant in various spin asymmetries. In particular, we found that a crucial
test of our predictions can be made by measuring the parity asymmetry and
beam-target double asymmetry at forward scattering angles.",0012012v1
2006-12-20,Spin motion at and near orbital resonance in storage rings with Siberian Snakes. Part I: at orbital resonance,"Here, and in a sequel, we invoke the invariant spin field to provide an
in--depth study of spin motion at and near low order orbital resonances in a
simple model for the effects of vertical betatron motion in a storage ring with
Siberian Snakes. This leads to a clear understanding, within the model, of the
behaviour of the beam polarisation at and near so--called snake resonances in
proton storage rings.",0612194v1
2008-04-14,On the observation of the spin resonance in superconducting CeCoIn_5,"Recent observation of a resonance spin excitation at (1/2,1/2,1/2) in the
superconducting state of CeCoIn_5 [C. Stock et al., Phys. Rev. Lett. {\bf 100}
087001 (2008)] was interpreted as an evidence for d_{x^2-y^2} gap symmetry, by
analogy with the cuprates. This is true if the resonance is a spin exciton. We
argue that such description is undermined by the three-dimensionality of
CeCoIn_5. We show that in 3D systems the excitonic resonance only emerges at
strong coupling, and is weak. We argue in favor of the alternative, magnon
scenario, which does not require a d_{x^2-y^2} gap.",0804.2217v1
2010-12-20,Zero field spin polarization in a 2D paramagnetic resonant tunneling diode,"We study I-V characteristics of an all-II-VI semiconductor resonant tunneling
diode with dilute magnetic impurities in the quantum well layer. Bound magnetic
polaron states form in the vicinity of potential fluctuations at the well
interface while tunneling electrons traverse these interface quantum dots. The
resulting microscopic magnetic order lifts the degeneracy of the resonant
tunneling states. Although there is no macroscopic magnetization, the resulting
resonant tunneling current is highly spin polarized at zero magnetic field due
to the zero field splitting. Detailed modeling demonstrates that the local spin
polarization efficiency exceeds 90% without an external magnetic field.",1012.4261v1
2011-12-05,Strong coupling of spin qubits to a transmission line resonator,"We propose a mechanism for coupling spin qubits formed in double quantum dots
to a superconducting transmission line resonator. Coupling the resonator to the
gate controlling the interdot tunneling creates a strong spin qubit--resonator
interaction with strength of tens of MHz. This mechanism allows operating the
system at a point of degeneracy where dephasing is minimized. The transmission
line can serve as a shuttle allowing for two-qubit operations, including fast
generation of qubit-qubit entanglement and the implementation of a
controlled-phase gate.",1112.0869v2
2013-05-23,Why is the Moon synchronously rotating?,"If the Moon's spin evolved from faster prograde rates, it could have been
captured into a higher spin-orbit resonance than the current 1:1 resonance. At
the current value of orbital eccentricity, the probability of capture into the
3:2 resonance is as high as 0.6, but it strongly depends on the temperature and
average viscosity of the Moon's interior. A warmer, less viscous Moon on a
higher-eccentricity orbit is even more easily captured into supersynchronous
resonances. We discuss two likely scenarios for the present spin-orbit state: a
cold Moon on a low-eccentricity orbit and a retrograde initial rotation.",1305.5441v1
2015-05-05,Spinor Stochastic Resonance,"We report on noise-induced-spin-ordering in a collective quasipaticle system:
spinor stochastic resonance. Synergetic interplay of a polarization-modulated
signal and a polarization-noise allows us to switch coherently between the two
metastable states of a microcavity-polariton spin bistable system. Spinor
stochastic resonance is demonstrated in a zero-dimensional GaAs based
microcavity. The resonance behavior of both the spin amplification and the
signal-to-noise ratio are experimentally evidenced as a function of the noise
strength for different amplitude modulations. They are theoretically reproduced
using a spinor- Gross-Pitaevskii equation driven by a randomly polarized laser
field.",1505.00929v1
2016-09-11,Angular dependence of electron spin resonance for detecting quadrupolar liquid state of frustrated spin chains,"Spin nematic phase is a phase of frustrated quantum magnets with a
quadrupolar order of electron spins. Since the spin nematic order is usually
masked in experimentally accessible quantities, it is important to develop a
methodology for detecting the spin nematic order experimentally. In this paper
we propose a convenient method for detecting quasi-long-range spin nematic
correlations of a quadrupolar Tomonaga-Luttinger liquid state of $S=1/2$
frustrated ferromagnetic spin chain compounds, using electron spin resonance
(ESR). We focus on linewidth of a so-called paramagnetic resonance peak in ESR
absorption spectrum. We show that a characteristic angular dependence of the
linewidth on the direction of magnetic field arises in the spin nematic phase.
Measurments of the angular dependence give a signature of the quadrupolar
Tomonaga-Luttinger liquid state. In our method we change only the direction of
the magnetic field, keeping the magnitude of the magnetic field and the
temperature. Therefore, our method is advantageous for investigating the
one-dimensional quadrupolar liquid phase that usually occupies only a narrow
region of the phase diagram.",1609.03114v2
2021-04-05,Spin Pumping of an Easy-Plane Antiferromagnet Enhanced by Dzyaloshinskii-Moriya Interaction,"Recently, antiferromagnets have received revived interest due to their
significant potential for developing next-generation ultrafast magnetic
storage. Here we report dc spin pumping by the acoustic resonant mode in a
canted easy-plane antiferromagnet {\alpha}-Fe2O3 enabled by the
Dzyaloshinskii-Moriya interaction. Systematic angle and frequency dependent
measurements demonstrate that the observed spin pumping signals arise from
resonance-induced spin injection and inverse spin Hall effect in
{\alpha}-Fe2O3/metal heterostructures, mimicking the behavior of spin pumping
in conventional ferromagnet/nonmagnet systems. The pure spin current nature is
further corroborated by reversal of the polarity of spin pumping signals when
the spin detector is switched from platinum to tungsten which has an opposite
sign of the spin Hall angle. Our results highlight the potential opportunities
offered by the low-frequency acoustic resonant mode in canted easy-plane
antiferromagnets for developing next-generation, functional spintronic devices.",2104.01796v2
2021-12-29,Pauli Spin Blockade in a Resonant Triple Quantum Dot Molecule,"Pauli spin blockade in quantum dot systems occurs when the charge transport
is allowed only for some spin states, and it has been an efficient tool in
spin-based qubit devices in semiconductors. We theoretically investigate a
Pauli spin blockade in a triple quantum dot molecule consisting of three
identical quantum dots in a semiconductor in the presence of an external
magnetic field through the molecule. When the three-electron state is on
resonance with two- or four-electron states, the Aharonov-Bohm oscillation and
the Zeeman splitting lead to a periodic spin blockade effect. We focus on the
spin blockade at a two- and three-electron resonance, and show that we can tune
the magnetic field to selectively allow only spin-singlet or spin-triplet state
to add an additional electron from tunnel-coupled leads. This spin blockade
maintains the three quantum dots at the optimal sweet spot against the charge
noise, demonstrating its potential as an efficient readout scheme for the
qubits in quantum dot systems.",2112.14810v2
2012-12-21,Percolation transition in the kinematics of nonlinear resonance broadening in Charney-Hasegawa-Mima model of Rossby wave turbulence,"We study the kinematics of nonlinear resonance broadening of interacting
Rossby waves as modelled by the Charney-Hasegawa-Mima equation on a biperiodic
domain. We focus on the set of wave modes which can interact quasi-resonantly
at a particular level of resonance broadening and aim to characterise how the
structure of this set changes as the level of resonance broadening is varied.
The commonly held view that resonance broadening can be thought of as a
thickening of the resonant manifold is misleading. We show that in fact the set
of modes corresponding to a single quasi-resonant triad has a nontrivial
structure and that its area in fact diverges for a finite degree of broadening.
We also study the connectivity of the network of modes which is generated when
quasi-resonant triads share common modes. This network has been argued to form
the backbone for energy transfer in Rossby wave turbulence. We show that this
network undergoes a percolation transition when the level of resonance
broadening exceeds a critical value. Below this critical value, the largest
connected component of the quasi-resonant network contains a negligible
fraction of the total number of modes in the system whereas above this critical
value a finite fraction of the total number of modes in the system are
contained in the largest connected component. We argue that this percolation
transition should correspond to the transition to turbulence in the system.",1212.5336v1
2023-10-25,Pauli resonance states in light nuclei: how they appear and how they can be eliminated,"Systematic analysis of parameters and properties of the Pauli resonance
states are performed for light nuclei $^{6}$Li, $^{7}$Li, $^{8}$Be, $^{9}$Be
and $^{10}$B, which are treated as two-cluster systems. The Pauli resonance
states are redundant solutions of the resonating group method appearing when
one try use more advanced description of the internal structure of interacting
clusters. Our calculations are performed in a standard and advanced versions of
the resonating group method. The standard version employs wave functions of
many-particle shell model to describe internal motion of nucleons within each
cluster. The advanced version is based on three-cluster resonating group
method. As in the standard version, the internal wave functions of three
clusters are approximated by wave functions of many-particle shell model model.
However, in advanced version one of pair of clusters forms a bound state, and
third cluster is considered to interact with such state. It is found that the
Pauli resonance states in nuclei under consideration have energy between 11 and
46 MeV, and their widths vary from 8 keV to 6.7 MeV. Analysis of wave functions
of Pauli resonance states and matrix elements of norm kernel allowed us to
formulate an effective method for eliminating Pauli resonance states. It is
demonstrated that this method effectively eliminate all determined the Pauli
resonance states.",2310.16373v3
2016-09-21,Paramagnetic resonance in spin-polarized disordered Bose-Einstein condensates,"We study the pseudo-spin density response of a disordered two-dimensional
spin-polarized Bose gas of exciton polaritons to weak alternating magnetic
field, assuming that one of the spin states of the doublet is macroscopically
occupied and Bose-condensed while the occupation of the other state remains
much smaller. We calculate spatial and temporal dispersions of spin
susceptibility of the gas taking into account spin-flip processes due to the
transverse-longitudinal splitting. Further, we use the Bogoliubov theory of
weakly-interacting gases and show that the time-dependent magnetic field power
absorption exhibits double resonance structure corresponding to two particle
spin states (contrast to paramagnetic resonance in regular spin-polarized
electron gas). We analyze the widths of these resonances caused by scattering
on the disorder and show that, in contrast with the ballistic regime, in the
presence of impurities, the polariton scattering on them is twofold: scattering
on the impurity potential directly and scattering on the spatially fluctuating
condensate density caused by the disorder. As a result, the width of the
resonance associated with the Bose-condensed spin state can be surprizingly
narrow in comparison with the width of the resonance associated with the
non-condensed state.",1609.06411v3
2023-01-06,Single electron-spin-resonance detection by microwave photon counting,"Electron spin resonance (ESR) spectroscopy is the method of choice for
characterizing paramagnetic impurities, with applications ranging from
chemistry to quantum computing, but it gives access only to ensemble-averaged
quantities due to its limited signal-to-noise ratio. Single-electron-spin
sensitivity has however been reached using spin-dependent photoluminescence,
transport measurements, and scanning-probe techniques. These methods are
system-specific or sensitive only in a small detection volume, so that
practical single spin detection remains an open challenge. Here, we demonstrate
single electron magnetic resonance by spin fluorescence detection, using a
microwave photon counter at cryogenic temperatures. We detect individual
paramagnetic erbium ions in a scheelite crystal coupled to a high-quality
factor planar superconducting resonator to enhance their radiative decay rate,
with a signal-to-noise ratio of 1.9 in one second integration time. The
fluorescence signal shows anti-bunching, proving that it comes from individual
emitters. Coherence times up to 3 ms are measured, limited by the spin
radiative lifetime. The method has the potential to apply to arbitrary
paramagnetic species with long enough non-radiative relaxation time, and allows
single-spin detection in a volume as large as the resonator magnetic mode
volume ( 10 um^3 in the present experiment), orders of magnitude larger than
other single-spin detection techniques. As such, it may find applications in
magnetic resonance and quantum computing.",2301.02653v2
2018-04-10,Measuring the properties of nearly extremal black holes with gravitational waves,"Characterizing the properties of black holes is one of the most important
science objectives for gravitational-wave observations. Astrophysical evidence
suggests that black holes that are nearly extremal (i.e. spins near the
theoretical upper limit) might exist and thus might be among the merging black
holes observed with gravitational waves. In this paper, we explore how well
current gravitational wave parameter estimation methods can measure the spins
of rapidly spinning black holes in binaries. We simulate gravitational-wave
signals using numerical-relativity waveforms for nearly-extremal, merging black
holes. For simplicity, we confine our attention to binaries with spins parallel
or antiparallel with the orbital angular momentum. We find that recovering the
holes' nearly extremal spins is challenging. When the spins are nearly extremal
and parallel to each other, the resulting parameter estimates do recover spins
that are large, though the recovered spin magnitudes are still significantly
smaller than the true spin magnitudes. When the spins are nearly extremal and
antiparallel to each other, the resulting parameter estimates recover the small
effective spin but incorrectly estimate the individual spins as nearly zero. We
study the effect of spin priors and argue that a commonly used prior (uniform
in spin magnitude and direction) hinders unbiased recovery of large black-hole
spins.",1804.03704v2
2016-04-20,Nonlinear wave damping due to multi-plasmon resonances,"For short wavelengths, it is well known that the linearized Wigner-Moyal
equation predicts wave damping due to wave-particle interaction, where the
resonant velocity shifted from the phase velocity by a velocity $v_q = \hbar
k/2m$. Here $\hbar$ is the reduced Planck constant, $k$ is the wavenumber and
$m$ is the electron mass. Going beyond linear theory, we find additional
resonances with velocity shifts $n v_q$, $n = 2, 3, \ldots$, giving rise to a
new wave-damping mechanism that we term \emph{multi-plasmon damping}, as it can
be seen as the simultaneous absorption (or emission) of multiple plasmon
quanta. Naturally this wave damping is not present in classical plasmas. For a
temperature well below the Fermi temperature, if the linear ($n = 1$) resonant
velocity is outside the Fermi sphere, the number of linearly resonant particles
is exponentially small, while the multi-plasmon resonances can be located in
the bulk of the distribution. We derive sets of evolution equations for the
case of two-plasmon and three-plasmon resonances for Langmuir waves in the
simplest case of a fully degenerate plasma. By solving these equations
numerically for a range of wave-numbers we find the corresponding damping
rates, and we compare them to results from linear theory to estimate the
applicability. Finally, we discuss the effects due to a finite temperature.",1604.05983v2
2003-08-27,Decay of the monochromatic capillary wave,"It was demonstrated by direct numerical simulation that, in the case of
weakly nonlinear capillary waves, one can get resonant waves interaction on the
discrete grid when resonant conditions are never fulfilled exactly. The waves's
decay pattern was obtained. The influence of the mismatch of resonant condition
was studied as well.",0308100v1
2003-10-20,Nonlinear resonant wave interaction in vacuum,"The basic equations governing propagation of electromagnetic and
gravitational waves in vacuum are nonlinear. As a consequence photon-photon
interaction as well as photon-graviton interaction can take place without a
medium. However, resonant interaction between less than four waves cannot occur
in vacuum, unless the interaction takes place in a bounded region, such as a
cavity or a waveguide. Recent results concerning resonant wave interaction in
bounded vacuum regions are reviewed and extended.",0310095v1
2004-07-29,The resonant behaviour of the Faraday rotation in a medium with linear birefringence,"It is shown that the monochromatic optical wave propagating through the
medium with linear birefringence in presence of a signal electromagnetic wave
(whose wavelength is equal to the polarization beats length), displays Faraday
rotation having the frequency of the signal wave and unsuppressed by linear
birefringence. The effect is resonant with respect to the frequency of a signal
wave. The ""sharpness"" of the resonance is defined by length of the birefringent
medium.",0407142v1
2008-02-05,Far-off-resonant wave interaction in one-dimensional photonic crystals with quadratic nonlinearity,"We extend a recently developed Hamiltonian formalism for nonlinear wave
interaction processes in spatially periodic dielectric structures to the
far-off-resonant regime, and investigate numerically the three-wave resonance
conditions in a one-dimensional optical medium with $\chi^{(2)}$ nonlinearity.
In particular, we demonstrate that the cascading of nonresonant wave
interaction processes generates an effective $\chi^{(3)}$ nonlinear response in
these systems. We obtain the corresponding coupling coefficients through
appropriate normal form transformations that formally lead to the Zakharov
equation for spatially periodic optical media.",0802.0561v1
2009-03-02,Sommerfeld enhancement for a Yukawa potential,"We show how easy it is to get the Sommerfeld enhancement for a Yukawa
potential, for definite partial waves, beyond the S wave analyzed in previous
literature. In particular, we report results for the P wave (for which there is
a resonant pattern and the enhancement can be of several orders of magnitude
even far from the resonance) that could be relevant for the analysis of
experimental cosmic rays data possibly signaling the annihilation of dark
matter particles.",0903.0317v2
2013-09-02,Counting of discrete Rossby/drift wave resonant triads,"The purpose of this note is to remove the confusion about counting of
resonant wave triads for Rossby and drift waves in the context of the
Charney-Hasegawa-Mima equation. In particular, we aim to point out a major
error of over-counting of triads in the paper ""Discrete exact and
quasi-resonances of Rossby/drift waves on beta-plane with periodic boundary
conditions"", by Kartashov and Kartashova, arXiv:1307.8272v1 [physics.flu-dyn]
(2013).",1309.0405v1
2013-10-04,Resonant Excitation of Tilt Mode in Tidally Deformed Disks,"In a previous paper (Kato 2013b), we have shown that in deformed disks a pair
of trapped oscillation modes can be resonantly excited through couplings with
disk deformation. In this paper we examine in what cases tilts are excited on
tidally deformed disks by the above-mentioned wave-wave resonant process. The
results show that tilts can be excited in various evolutional stages of tidally
deformed disks, although the wave mode which becomes the pair to the tilt and
the mode of tidal waves contributing to the resonance change by change of disk
stages.",1310.1140v1
2014-01-29,Optical Leaky-Wave Antenna Integrated in Ring Resonator,"A leaky-wave antenna at optical frequencies is designed and integrated with a
ring resonator at 1550 nm wavelength. The leaky wave is generated by using
periodic perturbations in the integrated dielectric waveguide that excite the
-1 spatial harmonic. The antenna consists of a dielectric waveguides with
semiconductor corrugations, and it is compatible with CMOS fabrication
technology. We show that integrating the leaky wave antenna in an optical ring
resonator that is fed by directional couplers, we can improve the electronic
control of the radiation through carrier injection into the semiconductor
corrugations.",1401.7609v1
2015-12-30,Features of electromagnetic waves in a complex plasma due to surface plasmon resonances on macroparticles,"The dielectric properties of complex plasma containing either metal or
dielectric spherical inclusions (macroparticles, dust) are investigated. We
focus on surface plasmon resonances on the macroparticle surfaces and their
effect on electromagnetic wave propagation. It is demonstrated that the
presence of surface plasmon oscillations significantly modifies plasma
electromagnetic properties by resonances and cutoffs in the effective
permittivity. This leads to related branches of electromagnetic waves and to
the wave band gaps. The results are discussed in the context of dusty plasma
experiments.",1512.09124v1
2023-06-01,Theoretical Analysis of Quartz Plate Acoustic Wave Resonators and Sensors Using Three-Dimensional Equations of Anisotropic Elasticity or Piezoelectricity,"This is a review of theoretical results from the three-dimensional equations
of anisotropic elasticity or linear piezoelectricity on waves and vibrations in
quartz crystal plates. It covers both the classical results on acoustic wave
resonators and the relatively new applications in acoustic wave sensors. It
discusses the basic thickness modes with various complications due to
electrodes, mass loading, contact with fluids, and air gaps, etc. as well as
the more complicated transversely varying modes. These results are fundamental
for the understanding and design optimization of the widely used quartz crystal
plate resonators and sensors.",2306.00604v1
2001-11-29,Resonant control of elastic collisions in an optically trapped Fermi gas of atoms,"We have loaded an ultracold gas of fermionic atoms into a far off resonance
optical dipole trap and precisely controlled the spin composition of the
trapped gas. We have measured a magnetic-field Feshbach resonance between atoms
in the two lowest energy spin-states, |9/2, -9/2> and |9/2, -7/2>. The
resonance peaks at a magnetic field of 201.5 plus or minus 1.4 G and has a
width of 8.0 plus or minus 1.1 G. Using this resonance we have changed the
elastic collision cross section in the gas by nearly 3 orders of magnitude.",0111571v1
2010-10-06,Ferromagnetic Resonance in Spinor Dipolar Bose--Einstein Condensates,"We used the Gross--Pitaevskii equations to investigate ferromagnetic
resonance in spin-1 Bose--Einstein condensates with a magnetic dipole-dipole
interaction. By introducing the dipole interaction, we obtained equations
similar to the Kittel equations used to represent ferromagnetic resonance in
condensed matter physics. These equations indicated that the ferromagnetic
resonance originated from dipolar interaction, and that the resonance frequency
depended upon the shape of the condensate. Furthermore, spin currents driven by
spin diffusions are characteristic of this system.",1010.1075v1
2018-02-19,Spin-Orbit Coupling Induced Resonance in an Ultracold Bose Gas,"We study a two-component Bose gas with artificial spin-orbit coupling (SOC)
which couples the center-of-mass momentum of atom to its internal states. We
show that in this system resonance can be induced by tuning SOC strength. With
a two-dimensional SOC, resonances in two scattering channels can be induced by
tuning the aspect ratio of SOC strengths. With a three-dimensional SOC,
resonance in all scattering channels can be induced by tuning the appropriate
SOC strength. Similarly, we also find that in a Fermi gas with two- or
three-dimensional SOC resonance can be induced by tuning SOC strength.",1802.06522v2
1997-04-03,Search for the πResonance in Two Particle Tunneling Experiments of YBCO Superconductors,"A recent theory of the resonant neutron scattering peaks in YBCO
superconductors predicts the existence of a sharp spin triplet two particle
collective mode (the ``\pi resonance"") in the normal state. In this paper, we
propose an experiment in which the \pi resonance could be probed directly in a
two particle tunneling measurement.",9704022v1
2000-05-13,Probing the Structure of Nucleons in the Resonance Region,"Status, open questions, and future prospects of the physics of excited
nucleons are discussed. Emphasis is on the study of the structure of nucleons
via measurements of their electromagnetic transition form factors, the search
for ""missing"" resonances, the spin structure of the nucleon in the resonance
region, and connections between the resonance and the deep-inelastic regimes.",0005033v1
2011-07-13,Two-Dimensional Propagation of a Photoinduced Spin Wave Packet,"We report the two-dimensional propagation of photoinduced spin wave packets
in Bi-doped rare-earth iron garnet. Spin waves were excited nonthermally and
impulsively by a circularly polarized light pulse via the inverse Faraday
effect. Space- and time resolved spin waves were detected with a
magneto-optical pump-probe technique. We investigated propagation in two
directions, parallel and perpendicular to the magnetic field. Backward volume
magnetostatic waves (BVMSWs) were detected in both directions. The frequency of
BVMSWs depends on the propagation direction. The experimental results agreed
well with the dispersion relation of BVMSWs.",1107.2457v1
2013-11-18,Antiferromagnetic Domain Wall Motion Induced by Spin Waves,"Spin waves in antiferromagnets are linearly or circularly polarized.
Depending on the polarization, traversing spin waves alter the staggered field
in a qualitatively different way. We calculate the drift velocity of a moving
domain wall as a result of spin wave mediated forces, and show that the domain
wall moves in opposite directions for linearly and circularly polarized waves.
The analytical results agree with a micromagnetics simulation of an
antiferromagnetic domain wall driven by a localized and alternating magnetic
field.",1311.4328v2
2015-09-09,Spin wave vortex from the scattering on Bloch point solitons,"The interaction of a spin wave with a stationary Bloch point is studied. The
topological non-trivial structure of the Bloch point manifests in the
propagation of spin waves endowing them with a gauge potential that resembles
the one associated with the interaction of a magnetic monopole and an electron.
By pursuing this analogy, we are led to the conclusion that the scattering of
spin waves and Bloch points is accompanied by the creation of a magnon vortex.
Interference between such a vortex and a plane wave leads to dislocations in
the interference pattern that can be measurable by means of magnon holography.",1509.02891v1
2021-03-15,Magnetically switchable spin wave retarder with $90^\circ$ antiferromagnetic domain wall,"Polarization, denoting the precession direction with respect to the
background magnetization, is an intrinsic degree of freedom of spin wave. Using
magnetic textures to control the spin wave polarization is fundamental and
indispensable toward reprogrammable polarization-based magnonics. Here, we show
that due to the intrinsic cubic anisotropy, a $90^\circ$ antiferromagnetic
domain wall naturally acts as a spin wave retarder (wave-plate). Moreover, for
a $90^\circ$ domain wall pair developed by introducing a second domain in a
homogenous antiferromagnetic wire, the sign of retarding effect can be flipped
by simply switching the direction of the intermediate domain.",2103.08342v2
2021-07-12,Spin wave driven domain wall motion in easy-plane ferromagnets: a particle perspective,"In easy-plane ferromagnets, we show that the interplay between a domain wall
and a spin wave packet can be formulated as the collision of two massive
particles with a gravity-like attraction. In the presence of magnetic
dissipation, the domain wall mimics a particle subject to viscous friction,
while the spin wave packet resembles a particle of variable mass. Due to
attractive nature of the interaction, the domain wall acquires a backward
displacement as a spin wave packet penetrating the domain wall, even though
there is no change in momentum of the wave packet before and after penetration.",2107.05401v2
2023-01-05,Universal scaling between wave speed and size enables nanoscale high-performance reservoir computing based on propagating spin-waves,"Neuromorphic computing using spin waves is promising for high-speed nanoscale
devices, but the realization of high performance has not yet been achieved.
Here we show, using micromagnetic simulations and simplified theory with
response functions, that spin-wave physical reservoir computing can achieve
miniaturization down to nanoscales keeping high computational power comparable
with other state-of-art systems. We also show the scaling of system sizes with
the propagation speed of spin waves plays a key role to achieve high
performance at nanoscales.",2301.02193v1
2015-07-10,Fractionalized spin-wave continuum in spin liquid states on the kagome lattice,"Motivated by spin-wave continuum (SWC) observed in recent neutron scattering
experiments in Herbertsmithite, we use Gutzwiller-projected wave functions to
study dynamic spin structure factor $S(\mathbf{q},\omega)$ of spin liquid
states on the kagome lattice. Spin-1 excited states in spin liquids are
represented by Gutzwiller-projected two-spinon excited wave functions. We
investigate three different spin liquid candidates, spinon Fermi-surface spin
liquid (FSL), Dirac spin liquid (DSL) and random-flux spin liquid (RSL). FSL
and RSL have low energy peaks in $S(\mathbf{q},\omega)$ at $K$ points in the
extended magnetic Brillouin zone, in contrast to experiments where low energy
peaks are found at $M$ points. There is no obviuos contradiction between DSL
and neutron scattering measurements. Besides a fractionalized spin (i.e.
spin-1/2), spinons in DSL carry a fractionalized crystal momentum which is
potentially detectable in SWC in the neutron scattering measurements.",1507.03007v1
2019-04-29,Unconventional spin currents in magnetic films,"A spin current - a flow of spin angular momentum - can be carried either by
spin polarised free electrons or by magnons, the quanta of a moving collective
oscillation of localised electron spins - a spin wave. Traditionally, it was
assumed, that a spin wave in a magnetic film with spin-sink-free surfaces can
transfer energy and angular momentum only along its propagation direction. In
this work, using Brillouin light scattering spectroscopy in combination with a
theory of dipole-exchange spin-wave spectra, we show that in obliquely
magnetized free magnetic films the in-plane propagation of spin waves is
accompanied by a transverse spin current along the film normal without any
corresponding transverse transport of energy.",1904.12610v1
2004-03-22,Strongest gravitational waves from neutrino oscillations at supernova core bounce,"Resonant active-to-active ($\nu_a \to \nu_a$), as well as active-to-sterile
($\nu_a \to \nu_s$) neutrino ($\nu$) oscillations can take place during the
core bounce of a supernova collapse. Besides, over this phase, weak magnetism
increases antineutrino ($\bar{\nu}$) mean free paths, and thus its luminosity.
Because the oscillation feeds mass-energy into the target $\nu$ species, the
large mass-squared difference between species ($\nu_a \to \nu_s$) implies a
huge amount of energy to be given off as gravitational waves ($L_{\textrm{GWs}}
\sim 10^{49}$ erg s$^{-1}$), due to anisotropic but coherent $\nu$ flow over
the oscillation length. This asymmetric $\nu$-flux is driven by both the
spin-magnetic and the {\it universal spin-rotation} coupling. The novel
contribution of this paper stems from 1) the new computation of the anisotropy
parameter $\alpha \sim 0.1-0.01$, and 2) the use of the tight constraints from
neutrino experiments as SNO and KamLAND, and the cosmic probe WMAP, to compute
the gravitational-wave emission during neutrino oscillations in supernovae core
collapse and bounce. We show that the mass of the sterile neutrino $\nu_s$ that
can be resonantly produced during the flavor conversions makes it a good
candidate for dark matter as suggested by Fuller et {\it al.} (2003). The new
spacetime strain thus estimated is still several orders of magnitude larger
than those from $\nu$ difussion (convection and cooling) or quadrupole moments
of neutron star matter. This new feature turns these bursts the more promissing
supernova gravitational-wave signal that may be detected by observatories as
LIGO, VIRGO, etc., for distances far out to the VIRGO cluster of galaxies.",0403529v1
2010-08-25,Neutron scattering study of the magnetic phase diagram of underdoped YBa(2)Cu(3)O(6+x),"We present a neutron triple-axis and resonant spin-echo spectroscopy study of
the spin correlations in untwinned YBCO crystals with x= 0.3, 0.35, and 0.45 as
a function of temperature and magnetic field. As the temperature T approaches
0, all samples exhibit static incommensurate magnetic order with propagation
vector along the a-direction in the CuO2 planes. The incommensurability delta
increases monotonically with hole concentration, as it does in LSCO. However,
delta is generally smaller than in LSCO at the same doping level. The intensity
of the incommensurate Bragg reflections increases with magnetic field for
YBCO(6.45) (superconducting Tc = 35 K), whereas it is field-independent for
YBCO(6.35) (Tc = 10 K). These results suggest that YBCO samples with x ~ 0.5
exhibit incommensurate magnetic order in the high fields used for the recent
quantum oscillation experiments on this system, which likely induces a
reconstruction of the Fermi surface. We present neutron spin-echo measurements
(with energy resolution ~ 1 micro-eV) for T > 0 that demonstrate a continuous
thermal broadening of the incommensurate magnetic Bragg reflections into a
quasielastic peak centered at excitation energy E = 0, consistent with the
zero-temperature transition expected for a two-dimensional spin system with
full spin-rotation symmetry. Measurements on YBCO(6.45) with a triple-axis
spectrometer (with energy resolution ~ 100 micro-eV) yield a crossover
temperature T_SDW ~ 30 K for the onset of quasi-static magnetic order. Upon
further heating, the wavevector characterizing low-energy spin excitations
approaches the commensurate antiferromagnetic wave vector, and the
incommensurability vanishes in an order-parameter-like fashion at an
""electronic liquid-crystal"" onset temperature T_ELC ~ 150 K. Both T_SDW and
T_ELC increase continuously as the Mott-insulating phase is approached with
decreasing doping level.",1008.4298v1
2021-08-10,Spin-excitation anisotropy in the nematic state of detwinned FeSe,"The origin of the electronic nematicity in FeSe is one of the most important
unresolved puzzles in the study of iron-based superconductors. In both spin-
and orbital-nematic models, the intrinsic magnetic excitations at
$\mathbf{Q}_1=(1, 0)$ and $\mathbf{Q}_2=(0, 1)$ of twin-free FeSe are expected
to provide decisive criteria for clarifying this issue. Although a
spin-fluctuation anisotropy below 10 meV between $\mathbf{Q}_1$ and
$\mathbf{Q}_2$ has been observed by inelastic neutron scattering around
$T_c\sim 9$ K ($<<T_s\sim 90$ K), it remains unclear whether such an anisotropy
also persists at higher energies and associates with the nematic transition
$T_{\rm s}$. Here we use resonant inelastic x-ray scattering (RIXS) to probe
the high-energy magnetic excitations of uniaxial-strain detwinned FeSe and
{\BFA}. A prominent anisotropy between the magnetic excitations along the $H$
and $K$ directions is found to persist to $\sim200$ meV in FeSe, which is even
more pronounced than the anisotropy of spin waves in {\BFA}. This anisotropy
decreases gradually with increasing temperature and finally vanishes at a
temperature around the nematic transition temperature $T_{\rm s}$. Our results
reveal an unprecedented strong spin-excitation anisotropy with a large energy
scale well above the $d_{xz}/d_{yz}$ orbital splitting, suggesting that the
nematic phase transition is primarily spin-driven. Moreover, the measured
high-energy spin excitations are dispersive and underdamped, which can be
understood from a local-moment perspective. Our findings provide the
much-needed understanding of the mechanism for the nematicity of FeSe and
points to a unified description of the correlation physics across seemingly
distinct classes of Fe-based superconductors.",2108.04484v2
2020-02-27,Distance measurements between carbon and bromine using a split-pulse PM-RESPDOR solid-state NMR experiment,"Solid-state NMR have been long used to probe atomic distances between nearby
nuclear spins by virtue of the dipolar interaction. New technological advances
have enabled simultaneous tuning of the radio-frequency resonance circuits to
nuclei with close Larmor frequencies, bringing a great promise also to distance
measurements between such nuclei, in particular for nuclei with a spin larger
than one-half. However, this new possibility has also required modifications of
those experiments since the two nuclei cannot be irradiated simultaneously.
When measuring distances between a spin S=1/2 and a quadrupolar spin (S > 1/2),
this drawback can be overcome by splitting the continuous-wave recoupling pulse
applied to the quadrupolar nucleus. We show here that a similar adjustment to a
highly-efficient phase-modulated (PM) recoupling pulse enables distance
measurements between nuclei with close Larmor frequencies, where the coupled
spin experiences a very large coupling. Such an experiment, split
phase-modulated RESPDOR, is demonstrated on a 13C-81Br system, where the
difference in Larmor frequencies is only 7%, or 11.2 MHz on a 14.1T magnet. The
inter-nuclear distances are extracted using an unscaled analytical formula.
Since bromine usually experiences particularly high quadrupolar couplings, as
in the current case, we suggest that the split-PM-RESPDOR experiment can be
highly beneficial for the research of bromo-compounds, including many
pharmaceuticals, where carbon-bromine bonds are prevalent, and organo-catalysts
utilizing the high reactivity of bromides. We show that for butyl
triphenylphosphonium bromide, distances are in agreement with a low-hydration
compound rather than a semi-clathrate form. The split-PM-RESPDOR experiment is
suitable for distance measurement between any quadrupolar/spin-1/2 pairs, in
particular when the quadrupolar spin experiences a significantly large
coupling.",2002.12022v2
2002-02-14,Effects of Charge Ordering on Spin-Wave of Quarter-Filled Spin-Density-Wave States,"Spin-wave excitations of quarter-filled spin-density-wave state, which
coexists with charge ordering, have been studied for one-dimensional extended
Hubbard model with the nearest-neighbor repulsive interaction (V) and
next-nearest-neighbor one (V_2). We calculate dispersion relations for the
acoustic and optical spin-wave within the random phase approximation. Our
numerical calculation shows that energy spectrum of the acoustic branch is well
described by a simple sine function form. In the states coexisting with
charge-density-wave, the spin-wave velocity decreases with increasing V or V_2.
Our numerical result, that velocity reduces to zero in the limit of large V or
V_2, is analyzed in terms of a spin 1/2 Heisenberg model with effective
antiferromagnetic exchange interaction.",0202227v2
2005-01-28,Spin waves in paramagnetic BCC iron: spin dynamics simulations,"Large scale computer simulations are used to elucidate a longstanding
controversy regarding the existence, or otherwise, of spin waves in
paramagnetic BCC iron. Spin dynamics simulations of the dynamic structure
factor of a Heisenberg model of Fe with first principles interactions reveal
that well defined peaks persist far above Curie temperature T_c. At large wave
vectors these peaks can be ascribed to propagating spin waves, at small wave
vectors the peaks correspond to over-damped spin waves. Paradoxically, spin
wave excitations exist despite only limited magnetic short-range order at and
above T_c.",0501713v1
2007-10-15,"Model for a collimated spin wave beam generated by a single layer, spin torque nanocontact","A model of spin torque induced magnetization dynamics based upon
semi-classical spin diffusion theory for a single layer nanocontact is
presented. The model incorporates effects due to the current induced Oersted
field and predicts the generation of a variety of spatially dependent,
coherent, precessional magnetic wave structures. Directionally controllable
collimated spin wave beams, vortex spiral waves, and localized standing waves
are found to be excited by the interplay of the Oersted field and the
orientation of an applied field. These fields act as a spin wave ``corral''
around the nanocontact that controls the propagation of spin waves in certain
directions.",0710.2890v3
2008-10-30,A Three-Terminal Spin-Wave Device for Logic Applications,"We demonstrate a three-terminal spin wave-based device utilizing spin wave
interference. The device consists of three coplanar transmission lines
inductively coupled to the 100nm thick CoFe film. Two spin wave signals are
excited by microwave fields produced by electric current in two sets of lines,
and the output signal is detected by the third set. The initial phases of the
spin wave signals are controlled by the direction of the current flow in the
excitation set of lines. Experimental data show prominent output signal
modulation as a function of the relative phase (in-phase and out-of phase) of
two input signals. The micrometer scale device operates in the GHz frequency
range and at room temperature. Our experimental results show that spin-wave
devices exploiting spin wave interference may be scaled to micrometer and
nanometer scales for potential logic circuit application.",0810.5589v1
2017-11-24,Antiferromagnetic domain wall motion driven by polarized spin waves,"The control of magnetic domain walls is essential for the magnetic-based
memory and logic applications. As an elementary excitation of magnetic order,
spin wave is capable of moving magnetic domain walls just as the conducting
electric current. Ferromagnetic spin waves can only be right-circularly
polarized. In contrast, antiferromagnetic spin waves have full polarization
degree of freedom, including both left- and right-circular polarizations, as
well as all possible linear or elliptical ones. Here we demonstrate that, due
to the Dzyaloshinskii-Moriya interaction, the spin wave driven domain wall
motion in antiferromagnets strongly depends on the linear polarization
direction of the injected spin waves. Steering domain wall motion by simply
tuning the polarization of spin waves offers new designing principles for
domain-wall based information processing devices.",1711.08929v1
2017-11-28,Spin-wave propagation in the presence of inhomogeneous Dzyaloshinskii-Moriya interactions,"We theoretically investigate spin-wave propagation through a magnetic
metamaterial with spatially modulated Dzyaloshinskii-Moriya interaction. We
establish an effective Sch{\""o}dinger equation for spin-waves and derive
boundary conditions for spin-waves passing through the boundary between two
regions having different Dzyaloshinskii-Moriya interactions. Based on these
boundary conditions, we find that the spin-wave can be amplified at the
boundary and the spin-wave bandgap is tunable either by an external magnetic
field or the strength of Dzyaloshinskii-Moriya interaction, which offers a
spin-wave analogue of the field-effect transistor in traditional electronics.",1711.10082v1
2018-12-20,Unidirectional spin-wave channeling along magnetic domain walls of Bloch type,"From the pioneering work of Winter [Phys. Rev. 124, 452 (1961)], a magnetic
domain wall of Bloch type is known to host a special wall-bound spin-wave mode,
which corresponds to spin-waves being channeled along the magnetic texture.
Using micromagnetic simulations, we investigate spin-waves travelling inside
Bloch walls formed in thin magnetic media with perpendicular-to-plane magnetic
anisotropy and we show that their propagation is actually strongly
nonreciprocal, as a result of dynamic dipolar interactions. We investigate
spin-wave non-reciprocity effects in single Bloch walls, which allows us to
clearly pinpoint their origin, as well as in arrays of parallel walls in stripe
domain configurations. For such arrays, a complex domain-wall-bound spin-wave
band structure develops, some aspects of which can be understood qualitatively
from the single-wall picture by considering that a wall array consists of a
sequence of up/down and down/up walls with opposite non-reciprocities.
Circumstances are identified in which the non-reciprocity is so extreme that
spin-wave propagation inside individual walls becomes unidirectional.",1812.08741v1
2017-06-06,Antiferromagnetic Domain Wall as Spin Wave Polarizer and Retarder,"As a collective quasiparticle excitation of the magnetic order in magnetic
materials, spin wave, or magnon when quantized, can propagate in both
conducting and insulating materials. Like the manipulation of its optical
counterpart, the ability to manipulate spin wave polarization is not only
important but also fundamental for magnonics. With only one type of magnetic
lattice, ferromagnets can only accommodate the right-handed circularly
polarized spin wave modes, which leaves no freedom for polarization
manipulation. In contrast, antiferromagnets, with two opposite magnetic
sublattices, have both left and right circular polarizations, and all linear
and elliptical polarizations. Here we demonstrate theoretically and confirm by
micromagnetic simulations that, in the presence of Dzyaloshinskii-Moriya
interaction, an antiferromagnetic domain wall acts naturally as a spin wave
polarizer or a spin wave retarder (waveplate). Our findings provide extremely
simple yet flexible routes toward magnonic information processing by harnessing
the polarization degree of freedom of spin wave.",1706.01617v1
2017-06-30,Spin-wave propagation in cubic anisotropic materials,"The information carrier of modern technologies is the electron charge whose
transport inevitably generates Joule heating. Spin-waves, the collective
precessional motion of electron spins, do not involve moving charges and thus
avoid Joule heating. In this respect, magnonic devices in which the information
is carried by spin-waves attract interest for low-power computing. However
implementation of magnonic devices for practical use suffers from low spin-wave
signal and on/off ratio. Here we demonstrate that cubic anisotropic materials
can enhance spin-wave signals by improving spin-wave amplitude as well as group
velocity and attenuation length. Furthermore, cubic anisotropic material shows
an enhanced on/off ratio through a laterally localized edge mode, which closely
mimics the gate-controlled conducting channel in traditional field-effect
transistors. These attractive features of cubic anisotropic materials will
invigorate magnonics research towards wave-based functional devices.",1706.10057v1
2019-03-03,Goos-Hanchen Shift of a Spin-Wave Beam at the Interface Between Two Ferromagnets,"Spin waves are promising information carriers which can be used in modern
magnonic devices, characterized by higher performance and lower energy
consumption than presently used electronic circuits. However, before practical
application of spin waves, the efficient control over spin wave amplitude and
phase needs to be developed. We analyze analytically reflection and refraction
of the spin waves at the interface between two ferromagnetic materials. In the
model we consider the system consisting of two semi-infinite ferromagnetic
media, separated by the ultra-narrow interface region with the magnetic
anisotropy. We have found the Goos-Hanchen shift for spin waves in transmission
and reflection, and performed detailed investigations of its dependence on the
anisotropy at the interface and materials surrounding the interface. We have
demonstrated possibility of obtaining Goos-Hanchen shift of several wavelengths
in reflection for realistic material parameters. That proves the possibility
for change of the spin waves phase in ferromagnetic materials at subwavelength
distances, which can be regarded as a metasurface for magnonics.",1903.00861v1
2019-04-25,Controlled interconversion of quantized spin wave modes via local magnetic fields,"In the emerging field of magnonics, spin waves are considered for information
processing and transmission at high frequencies. Towards this end, the
manipulation of propagating spin waves in nanostructured waveguides for novel
functionality has recently been attracting increasing focus of research.
Excitations with uniform magnetic fields in such waveguides favors symmetric
spin wave modes with odd quantization numbers. Interference between multiple
odd spin wave modes leads to a periodic self-focusing effect of the propagating
spin waves. Here we demonstrate, how antisymmetric spin wave modes with even
quantization numbers can be induced by local magnetic fields in a
well-controlled fashion. The resulting interference patterns are discussed
within an analytical model and experimentally demonstrated using microfocused
Brillouin light scattering ({\mu}-BLS).",1904.11613v1
2020-05-06,Observation of evanescent spin waves in the magnetic dipole regime,"We observed spin-wave transmission through an air gap that works as a
prohibited region. The spin waves were excited by circularly polarized pump
pulses via the inverse Faraday effect, and their spatial propagation was
detected through the Faraday effect of probe pulses using a pump-probe imaging
technique. The experimentally observed spin-wave transmission was reproduced
using numerical calculations with a Green's function method and micromagnetic
simulation. We found that the amplitude of the spin waves decays exponentially
in the air gap, which indicates the existence of evanescent spin waves in the
magnetic dipole regime. This finding will pave the way for controllable
amplitudes and phases of spin waves propagating through an artificial magnonic
crystal.",2005.02559v1
2020-07-06,Hippopede curves for modelling radial spin waves in an azimuthal graded magnonic landscape,"We propose a mathematical model for describing radially propagating spin
waves emitted from the core region in a magnetic patch with n vertices in a
magnetic vortex state. The azimuthal anisotropic propagation of surface spin
waves (SSW) into the domain, and confined spin waves (or Winter's Magnons, WM)
in domain walls increases the complexity of the magnonic landscape. In order to
understand the spin wave propagation in these systems, we first use an approach
based on geometrical curves called 'hippopedes', however it provides no insight
into the underlying physics. Analytical models rely on generalized expressions
from the dispersion relation of SSW with an arbitrary angle between
magnetization M and wavenumber k. The derived algebraic expression for the
azimuthal dispersion is found to be equivalent to that of the 'hippopede'
curves. The fitting curves from the model yield a spin wave wavelength for any
given azimuthal direction, number of patch vertices and excitation frequency,
showing a connection with fundamental physics of exchange dominated surface
spin waves. Analytical results show good agreement with micromagnetic
simulations and can be easily extrapolated to any n-corner patch geometry.",2007.02646v2
2021-01-28,Electrical spin-wave spectroscopy in nanoscale waveguides with nonuniform magnetization,"Spin waves modes in magnetic waveguides with width down to 320 nm have been
studied by electrical propagating spin-wave spectroscopy and micromagnetic
simulations for both longitudinal and transverse magnetic bias fields. For
longitudinal bias fields, a 1.3 GHz wide spin-wave band was observed in
agreement with analytical dispersion relations for uniform magnetization.
However, transverse bias field led to several distinct bands, corresponding to
different quantized width modes, with both negative and positive slopes.
Micromagnetic simulations showed that, in this geometry, the magnetization was
nonuniform and tilted due to the strong shape anisotropy of the waveguides.
Simulations of the quantized spin-wave modes in such nonuniformly magnetized
waveguides resulted in spin wave dispersion relations in good agreement with
the experiments.",2101.11983v2
2023-06-08,Unidirectionality of spin waves in Synthetic Antiferromagnets,"We study the frequency non-reciprocity of the spin waves in symmetric
CoFeB/Ru/CoFeB synthetic antiferromagnets stacks set in the scissors state by
in-plane applied fields. Using a combination of Brillouin Light Scattering and
propagating spin wave spectroscopy experiments, we show that the acoustical
spin waves in synthetic antiferromagnets possess a unique feature if their
wavevector is parallel to the applied field: the frequency non-reciprocity due
to layer-to-layer dipolar interactions can be so large that the acoustical spin
waves transfer energy in a unidirectional manner for a wide and bipolar
interval of wavevectors. Analytical modeling and full micromagnetic
calculations are conducted to account for the dispersion relations of the
optical and acoustical spin waves for arbitrary field orientations. Our
formalism provides a simple and direct method to understand and design devices
harnessing unidirectional propagation of spin waves in synthetic
antiferromagnets.",2306.05259v2
2023-07-24,Unidirectional spin wave emission by travelling pair of magnetic field profiles,"We demonstrate that the spin wave Cherenkov effect can be used to design the
unidirectional spin wave emitter with tunable frequency and switchable
direction of emission. In our numerical studies, we propose to use a pair of
traveling profiles of the magnetic field which generate the spin waves, for
sufficiently large velocity of their motion. In the considered system, the spin
waves of shorter (longer) wavelengths are induced at the front (back) of the
moving profiles and interfere constructively or destructively, depending on the
velocity of the profiles. Moreover, we showed that the spin waves can be
confined between the pair of traveling profiles of the magnetic field. This
work opens the perspectives for the experimental studies in hybrid
magnonic-superconducting systems where the magnetic vortices in a
superconductor can be used as moving sources of the magnetic field driving the
spin waves in the ferromagnetic subsystem.",2307.12653v2
1998-12-16,Elementary excitations of magnetically ordered systems with orbital degeneracy,"The Holstein-Primakoff transformation is generalized to develop a quantum
flavor wave theory for spin systems with orbital degeneracy. Elementary
excitations consist of spin, orbital, and spin-orbital waves. Spin and
spin-orbital waves couple each other due to orbital anisotropy and Hund's rule,
resulting in new modes observable by inelastic neutron scattering. In the SU(4)
limit, flavor waves are dispersionless along one or more directions, and give
rise to quantum fluctuations of reduced dimensionality.",9812289v1
1999-09-02,Orbital Polarization and Fluctuation in Manganese Oxides,"In a form which include the mother compound, we studied the extended
Hubbard-type model with the orbital degeneracy for any doping concentration.
Meanfield phase diagram and the spin wave excitation in RPA are calculated. It
turned out that a large orbital polarization is essential to reproduce the
magnetic phases depending on the doping concentration. Base on this result, we
discuss the spin canting, the spin wave dispersion, and spin wave stiffness
from the standing point of the large orbital polarization. We also discuss the
orbital fluctuation which turned out to be important in the ferromagnetic
metallic region where the CMR is observed. Spin wave softening near the zone
boundary is also discussed in this context.",9909023v1
2000-05-09,Spin-Waves in itinerant ferromagnets,"We introduce a novel approach for the investigation of spin-wave excitations
in itinerant ferromagnets. Our theory is based on a variational treatment of
general multi-band Hubbard models which describe elements and compounds of
transition metals. The magnon dispersion is derived approximately as the energy
of a variational spin-wave state in the limit of large spatial dimensions. A
numerical evaluation of our results is feasible for general multi-band models.
As a first application we consider a model with two degenerate orbitals per
lattice site. From our results we can conclude that spin-wave excitations in
strong itinerant ferromagnets are very similar to those in ferromagnetic spin
systems.",0005154v1
2002-07-26,Spin Wave Response in the Dilute Quasi-one Dimensional Ising-like Antiferromagnet CsCo_{0.83}Mg_{0.17}Br_3,"Inelastic neutron scattering profiles of spin waves in the dilute
quasi-one-dimensional Ising-like antiferromagnet CsCo_{0.83}Mg_{0.17}Br_3 have
been investigated. Calculations of S^{xx}(Q,omega), based on an effective spin
Hamiltonian, accurately describe the experimental spin wave spectrum of the 2J
mode. The Q dependence of the energy of this spin wave mode follows the
analytical prediction
omega_{xx}(Q)=(2J)(1-5epsilon^{2}cos^{2}Qa+2epsilon^{2})^{1/2}, calculated by
Ishimura and Shiba using perturbation theory.",0207638v1
2005-08-07,Circular Polarization and Quantum Spin: A Unified Real-Space Picture of Photons and Electrons,"A classical circularly polarized electromagnetic wave carries angular
momentum, and represents the classical limit of a photon, which carries
quantized spin. It is shown that a very similar picture of a circularly
polarized coherent wave can account for both the spin of an electron and its
quantum wave function, in a Lorentz-invariant fashion. The photon-electron
interaction occurs through the usual electromagnetic potentials, modulating the
frequency and wavevector (energy and momentum) of this rotating spin field.
Other quantum particles can also be represented either as rotating spin fields,
or as composites of such fields. Taken together, this picture suggests an
alternative interpretation of quantum mechanics based solely on coherent wave
packets, with no point particles present.",0508064v1
2010-08-26,Localized collapse and revival of coherence in an ultracold Bose gas,"We study the collapse and revival of coherence induced by dipolar spin waves
in a trapped gas of Rb-87 atoms. In particular we observe spatially localized
collapse and revival of Ramsey fringe contrast and show how the pattern of
coherence depends on strength of the spin wave excitation. We find that the
spatial character of the coherence dynamics is incompatible with a simple model
based only on position-space overlap of wave functions. This phenomenon
requires a full phase-space description of the atomic spin using a quantum
Boltzmann transport equation, which highlights spin wave-induced coherent spin
currents and the ensuing dynamics they drive.",1008.4428v1
2014-07-01,Spin waves and spin instabilities in quantum plasmas,"We describe main ideas of method of many-particle quantum hydrodynamics
allows to derive equations for description of quantum plasma evolution. We also
present definitions of collective quantum variables suitable for quantum
plasmas. We show that evolution of magnetic moments (spins) in quantum plasmas
leads to several new branches of wave dispersion: spin-electromagnetic plasma
waves and self-consistent spin waves. Propagation of neutron beams through
quantum plasmas is also considered. Instabilities appearing due to interaction
of magnetic moments of neutrons with plasma are described.",1407.0355v1
2015-11-25,Topological spin waves in the atomic-scale magnetic skyrmion crystal,"We study the spin waves of the triangular skyrmion crystal that emerges in a
two dimensional spin lattice model as a result of the competition between
Heisenberg exchange, Dzyalonshinkii-Moriya interactions, Zeeman coupling and
uniaxial anisotropy. The calculated spin wave bands have a finite Berry
curvature that, in some cases, leads to non-zero Chern numbers, making this
system topologically distinct from conventional magnonic systems. We compute
the edge spin-waves, expected from the bulk-boundary correspondence principle,
and show that they are chiral, which makes them immune to elastic
backscattering. Our results illustrate how topological phases can occur in
self-generated emergent superlattices at the mesoscale.",1511.08244v1
2012-09-09,Neutron Brillouin scattering with pulsed spallation neutron source - spin-wave excitations from ferromagnetic powder samples -,"Neutron Brillouin scattering (NBS) method was developed using a pulsed
spallation neutron source, and the feasibility of NBS was demonstrated by
observing ferromagnetic spin waves in La$_{0.8}$Sr$_{0.2}$MnO$_3$ and SrRuO$_3$
powders. Gapless spin-wave excitations were observed in
La$_{0.8}$Sr$_{0.2}$MnO$_3$, which were continuously extended to the lower
scattering vector $Q$ from previous results using single crystals. The novel
result is a well-defined quadratic $Q$ dependence in the spin-wave dispersion
curve with a large energy gap in SrRuO$_3$ indicating robust spin-orbit
coupling.",1209.1780v1
2018-12-18,Magnetic excitations in frustrated fcc type-III antiferromagnet MnS$_2$,"Spin wave dispersion in the frustrated fcc type-III antiferromagnet MnS$_2$
has been determined by inelastic neutron scattering using a triple-axis
spectrometer. Existence of multiple spin wave branches, with significant
separation between high-energy and low-energy modes highlighting the intrinsic
magnetic frustration effect on the fcc lattice, is explained in terms of a spin
wave analysis carried out for the antiferromagnetic Heisenberg model for this
$S=5/2$ system with nearest and next-nearest-neighbor exchange interactions.
Comparison of the calculated dispersion with spin wave measurement also reveals
small suppression of magnetic frustration resulting from reduced exchange
interaction between frustrated spins, possibly arising from anisotropic
deformation of the cubic structure.",1812.07267v1
2019-05-29,Spin wave propagation in ferrimagnetic $Gd_{x}Co_{1-x}$,"Recent advances in antiferromagnetic spin dynamics using rare-earth (RE) and
transition-metal (TM) ferrimagnets have attracted much interest for spintronic
devices with a high speed and density. In this study, the spin wave properties
in the magnetostatic backward volume mode and surface mode in RE-TM
ferrimagnetic $Gd_{x}Co_{1-x}$ films with various composition x are
investigated using spin wave spectroscopy. The obtained group velocity and
attenuation length are well explained by the ferromagnet-based spin wave theory
when the composition of $Gd_{x}Co_{1-x}$ is far from the compensation point.",1905.12771v1
2017-01-20,Asymmetric Spin-wave Dispersion on Fe(110): Direct Evidence of Dzyaloshinskii--Moriya Interaction,"The influence of the Dzyaloshinskii-Moriya interaction on the spin-wave
dispersion in an Fe double layer grown on W(110) is measured for the first
time. It is demonstrated that the Dzyaloshinskii-Moriya interaction breaks the
degeneracy of spin waves and leads to an asymmetric spin-wave dispersion
relation. An extended Heisenberg spin Hamiltonian is employed to obtain the
longitudinal component of the Dzyaloshinskii-Moriya vectors from the
experimentally measured energy asymmetry.",1701.05854v1
2022-02-23,Nonlinear Coupling of Electromagnetic and Spin-Electron-Acoustic Waves in Spin-polarized Degenerate Relativistic Astrophysical Plasma,"Propagation of the finite amplitude electromagnetic wave through the
partially spin-polarized degenerate plasmas leads to the instability. The
instability happens at the interaction of the electromagnetic wave with the
small frequency longitudinal spin-electron-acoustic waves. Strongest
instability happens in the high density degenerate plasmas with the Fermi
momentum close to $m_{e}c$, where $m_{e}$ is the mass of electron, and $c$ is
the speed of light. The increase of the increment of instability with the
growth of the spin polarization of plasmas is found.",2202.11814v1
2022-12-02,Interplay between spin wave and magnetic vortex,"In this paper, the interplay between spin wave and magnetic vortex is
studied. We find three types of magnon scatterings: skew scattering, symmetric
side deflection and back reflection, which associate with respectively magnetic
topology, energy density distribution and linear momentum transfer torque
within vortex. The vortex core exhibits two translational modes: the intrinsic
circular mode and a coercive elliptical mode, which can be excited based on
permanent and periodic magnon spin-transfer torque effects of spin wave.
Lastly, we propose a vortex-based spin wave valve in which via inhomogeneity
modulation we access arbitrary control of the phase shift.",2212.01172v1
2008-01-31,Cosmological black hole spin evolution by mergers and accretion,"Using recent results from numerical relativity simulations of black hole
mergers, we revisit previous studies of cosmological black hole spin evolution.
We show that mergers are very unlikely to yield large spins, unless alignment
of the spins of the merging holes with the orbital angular momentum is very
efficient. We analyze the spin evolution in three specific scenarios: (1) spin
evolves only through mergers, (2) spin evolves through mergers and prolonged
accretion episodes, (3) spin evolves through mergers and short-lived (chaotic)
accretion episodes. We study how different diagnostics can distinguish between
these evolutionary scenarios, assessing the discriminating power of
gravitational-wave measurements and X-ray spectroscopy. Gravitational radiation
can produce three different types of spin measurements, yielding respectively
the spins of the two black holes in a binary inspiral prior to merger, the spin
of the merger remnant (as encoded in the ringdown waves), and the spin of
``single'' black holes during the extreme mass-ratio inspiral (EMRI) of compact
objects. The latter spin population is also accessible to iron-line
measurements. We compute and compare the spin distributions relevant for these
different observations. If iron-line measurements and gravitational-wave
observations of EMRIs only yield dimensionless spins j=J/M^2>0.9, then
prolonged accretion should be responsible for spin-up, and chaotic accretion
scenarios would be very unlikely. If only a fraction of the whole population of
low-redshift black holes spins rapidly, spin-alignment during binary mergers
(rather than prolonged accretion) could be responsible for spin-ups.",0802.0025v2
2013-09-10,Spin rectification induced by dynamical Hanle effect,"Dynamic response of spin accumulation to a time-dependent magnetic field has
been investigated in a ferromagnetic/nonmagnetic bilayer under ferromagnetic
resonance. In this system, magnetization precession driven by a microwave
generates direct-current (dc) and alternate-current (ac) spin accumulation in
the nonmagnetic layer by the spin pumping. The ac spin accumulation is coupled
with the microwave magnetic field through a dynamical Hanle spin precession,
giving rise to rectified spin accumulation comparable with the dc spin
accumulation directly generated by the spin pumping.",1309.2365v1
2020-01-25,Electron spin transport driven by surface plasmon polariton,"We propose a mechanism of angular momentum conversion from optical transverse
spin in surface plasmon polaritons (SPPs) to conduction electron spin. Free
electrons in the metal follow the transversally spinning electric field of SPP,
and the resulting orbital motions create inhomogeneous static magnetisation in
the metal. By solving the spin diffusion equation in the SPP, we find that the
magnetisation field generates an electron spin current. We show that there
exists a resonant condition where the spin current is resonantly enhanced, and
the polarisation of the spin current is flipped. Our theory reveals a novel
functionality of SPP as a spin current source.",2001.09286v1
2012-08-27,Photo-magnonics,"In the framework of magnonics all-optical femtosecond laser experiments are
used to study spin waves and their relaxation paths. Magnonic crystal
structures based on antidots allow the control over the spin-wave modes. In
these two-dimensional magnetic metamaterials with periodicities in the
wave-length range of dipolar spin waves the spin-wave bands and dispersion are
modified. Hence, a specific selection of spin-wave modes excited by laser
pulses is possible. Different to photonics, the modes depend strongly on the
strength of the magneto-static potential at around each antidot site - the
dipolar field. While this may lead to a mode localization, also for filling
fractions around or below 10%, Bloch states are found in low damping
ferromagnetic metals. In this chapter, an overview of these mechanisms is given
and the connection to spin-wave band spectra calculated from an analytical
model is established. Namely, the plane-wave method yields flattened bands as
well as band gaps at the antidot lattice Brillouin zone boundary.",1208.5383v1
2013-08-02,Extraordinary momentum and spin in evanescent waves,"Momentum and spin represent fundamental dynamical properties of quantum
particles and fields. In particular, propagating optical waves (photons) carry
momentum and longitudinal spin determined by the wave vector and circular
polarization, respectively. Here we show that exactly the opposite can be the
case for evanescent optical waves. A single evanescent wave possesses a spin
component, which is independent of the polarization and is orthogonal to the
wave vector. Furthermore, such a wave carries a momentum component, which is
determined by the circular polarization and is also orthogonal to the wave
vector. We show that these extraordinary properties reveal a fundamental
Belinfante's spin momentum, known in field theory and unobservable in
propagating fields. We demonstrate that the transverse momentum and spin push
and twist a probe Mie particle in an evanescent field. This allows the
observation of `impossible' properties of light and of a fundamental
field-theory quantity, which was previously considered as `virtual'.",1308.0547v3
2014-03-21,Interface boundary conditions for dynamic magnetization and spin wave dynamics in a ferromagnetic layer with the interface Dzyaloshinskii-Moriya interaction,"In this work we derive the interface exchange boundary conditions for the
classical linear dynamics of magnetization in ferromagnetic layers with the
interface Dzyaloshinskii-Moriya interaction (IDMI). We show that IDMI leads to
pinning of dynamic magnetization at the interface. An unusual peculiarity of
the IDMI-based pinning is that its scales as the spin-wave wave number. We
incorporate these boundary conditions into an existing numerical model for the
dynamics of the Damon-Eshbach spin wave in ferromagnetic films. IDMI affects
the dispersion and the frequency non-reciprocity of the traveling Damon-Eshbach
spin wave. For a broad range of film thicknesses L and wave numbers the results
of the numerical simulations of the spin wave dispersion are in a good
agreement with a simple analytical expression which shows that the contribution
of IDMI to the dispersion scales as 1/L, similarly to the effect of other types
of interfacial anisotropy. Suggestions to experimentalists how to detect the
presence of IDMI in a spin wave experiment are given.",1403.5385v4
2019-03-19,Broadband magnetoelastic coupling in magphonic crystals for high-frequency nanoscale spin wave generation,"Spin waves are promising candidates for information carriers in advanced
technology. The interactions between spin waves and acoustic waves in magnetic
nanostructures are of much interest because of their potential application for
spin wave generation, amplification and transduction. We investigate
numerically the dynamics of magnetoelastic excitations in a one-dimensional
magphonic crystal consisting of alternating layers of permalloy and cobalt. We
use the plane wave method and the finite element method for frequency- and
time-domain simulations, respectively. The studied structure is optimized for
hybridization of specific spin-wave and acoustic dispersion branches in the
entire Brillouin zone in a broad frequency range. We show that this type of
periodic structure can be used for efficient generation of high-frequency spin
waves.",1903.08024v1
2020-12-08,Nanoscale neural network using non-linear spin-wave interference,"We demonstrate the design of a neural network, where all neuromorphic
computing functions, including signal routing and nonlinear activation are
performed by spin-wave propagation and interference. Weights and
interconnections of the network are realized by a magnetic field pattern that
is applied on the spin-wave propagating substrate and scatters the spin waves.
The interference of the scattered waves creates a mapping between the wave
sources and detectors. Training the neural network is equivalent to finding the
field pattern that realizes the desired input-output mapping. A custom-built
micromagnetic solver, based on the Pytorch machine learning framework, is used
to inverse-design the scatterer. We show that the behavior of spin waves
transitions from linear to nonlinear interference at high intensities and that
its computational power greatly increases in the nonlinear regime. We envision
small-scale, compact and low-power neural networks that perform their entire
function in the spin-wave domain.",2012.04594v1
2011-10-12,How terrestrial planets traverse spin-orbit resonances: A camel goes through a needle's eye,"The dynamical evolution of terrestrial planets resembling Mercury in the
vicinity of spin-orbit resonances is investigated using comprehensive harmonic
expansions of the tidal torque taking into account the frequency-dependent
quality factors and Love numbers. The torque equations are integrated
numerically with a small step in time, includng the oscillating triaxial torque
components but neglecting the layered structure of the planet and assuming a
zero obliquity. We find that a Mercury-like planet with its current value of
orbital eccentricity (0.2056) is always captured in the 3:2 resonance. The
probability of capture in the higher 2:1 resonance is approximately 0.23. These
results are confirmed by a semi-analytical estimation of capture probabilities
as functions of eccentricity for both prograde and retrograde evolution of spin
rate. As follows from analysis of equilibrium torques, entrapment in the 3:2
resonance is inevitable at eccentricities between 0.2 and 0.41. Considering the
phase space parameters at the times of periastron, the range of spin rates and
phase angles, for which an immediate resonance passage is triggered, is very
narrow, and yet, a planet like Mercury rarely fails to align itself into this
state of unstable equilibrium before it traverses the 2:1 resonance.",1110.2658v3
2010-08-03,Tonks-Girardeau and Super Tonks-Girardeau States of a Trapped 1D Spinor Bose Gas,"A harmonically trapped ultracold 1D spin-1 Bose gas with strongly repulsive
or attractive 1D even-wave interactions induced by a 3D Feshbach resonance is
studied. The exact ground state, a hybrid of Tonks-Girardeau (TG) and ideal
Fermi gases, is constructed in the TG limit of infinite even-wave repulsion by
a spinor Fermi-Bose mapping to a spinless ideal Fermi gas. It is then shown
that in the limit of infinite even-wave attraction this same state remains an
exact many-body eigenstate, now highly excited relative to the collapsed
generalized McGuire cluster ground state, showing that the hybrid TG state is
completely stable against collapse to this cluster ground state under a sudden
switch from infinite repulsion to infinite attraction. It is shown to be the TG
limit of a hybrid super Tonks-Girardeau (STG) state which is metastable under a
sudden switch from finite but very strong repulsion to finite but very strong
attraction. It should be possible to create it experimentally by a sudden
switch from strongly repulsive to strongly attractive interaction, as in the
recent Innsbruck experiment on a spin-polarized bosonic STG gas. In the case of
strong attraction there should also exist another STG state of much lower
energy, consisting of strongly bound dimers, a bosonic analog of a recently
predicted STG gas which is an ultracold gas of strongly bound bosonic dimers of
fermionic atoms, but it is shown that this STG state cannot be created by such
a switch from strong repulsion to strong attraction.",1008.0428v2
2016-07-16,Lifetimes and wave functions of ozone metastable vibrational states near the dissociation limit in full symmetry approach,"Energies and lifetimes (widths) of vibrational states above the lowest
dissociation limit of $^{16}$O$_3$ were determined using a previously-developed
efficient approach, which combines hyperspherical coordinates and a complex
absorbing potential. The calculations are based on a recently-computed
potential energy surface of ozone determined with a spectroscopic accuracy [J.
Chem. Phys. {\bf 139}, 134307 (2013)]. The effect of permutational symmetry on
rovibrational dynamics and the density of resonance states in O$_3$ is
discussed in detail. Correspondence between quantum numbers appropriate for
short- and long-range parts of wave functions of the rovibrational continuum is
established. It is shown, by symmetry arguments, that the allowed purely
vibrational ($J=0$) levels of $^{16}$O$_3$ and $^{18}$O$_3$, both made of
bosons with zero nuclear spin, cannot dissociate on the ground state potential
energy surface. Energies and wave functions of bound states of the ozone
isotopologue $^{16}$O$_3$ with rotational angular momentum $J=0$ and 1 up to
the dissociation threshold were also computed. For bound levels, good agreement
with experimental energies is found: The RMS deviation between observed and
calculated vibrational energies is 1~\cm. Rotational constants were determined
and used for a simple identification of vibrational modes of calculated levels.",1607.04749v1
2019-03-04,Possible $S$-wave $ND^{(*)}$ and $N\bar B^{(*)}$ bound states in a chiral quark model,"$S$-wave bound-states composed of a nucleon($N$) and a heavy meson ($D$,
$D^*$, $\bar{B}$ or $\bar{B}^*$) are investigated in both the chiral SU(3)
quark model and the extended chiral SU(3) quark model by solving the resonating
group method equation. The results reveal that the $ND$ and $ND^*$ interactions
in the corresponding relative $S$-wave states are attractive, arising mainly
from one boson exchange processes between light quarks. It is shown that these
attractions are strong enough to form six $ND$ and $ND^*$ $S$-wave bound states
in the extended chiral SU(3) quark model with the binding energies in the range
of $3-45$ MeV, and three $S$-wave bound states within the chiral SU(3) quark
model with binding energies of $2-8$ MeV. In particular, the experimentally
observed $\Sigma_c(2800)$ is interpreted to be most likely an $S-$wave $ND$
state with the total isopsin $I=0$ and spin-parity $J^P=1/2^-$, while
$\Lambda_c(2940)^+$ as an $S-$wave $ND^*$ state with $I=0$ and $J^P=3/2^-$.
Further information on the $ND$ and $ND^*$ interactions in the (unbound)
scattering kinematics are obtained from the corresponding $S$-wave phase
shifts. The $N\bar{B}$ and $N\bar{B}^*$ systems are also investigated within
the present two models and some $S-$wave bound states with binding energies in
the range of $1-60$ MeV are predicted in these systems: six (in total) within
the extended chiral SU(3) quark model and, four, within the chiral SU(3) quark
model.",1903.01207v1
2017-01-27,Are Hidden-Variable Theories for Pilot-Wave Systems Possible ?,"Recently it was shown that certain fluid-mechanical 'pilot-wave' systems can
strikingly mimic a range of quantum properties, including single particle
diffraction and interference, quantization of angular momentum etc. How far
does this analogy go? The ultimate test of (apparent) quantumness of such
systems is a Bell-test. Here the premises of the Bell inequality are
re-investigated for particles accompanied by a pilot-wave, or more generally by
a resonant 'background' field. We find that two of these premises, namely
outcome independence and measurement independence, may not be generally valid
when such a background is present. Under this assumption the Bell inequality is
possibly (but not necessarily) violated. A class of hydrodynamic Bell
experiments is proposed that could test this claim. Such a Bell test on fluid
systems could provide a wealth of new insights on the different loopholes for
Bell's theorem. Finally, it is shown that certain properties of
background-based theories can be illustrated in Ising spin-lattices.",1701.08194v2
2020-02-28,A Charge Density Wave-like Transition in High Temperature Quenched $Bi_2Se_3$,"Hexagonally deformed Fermi surfaces and strong nesting, found in topological
insulators (TIs) such as $Bi_2Se_3$ and $Bi_2Te_3$, have led to several
predictions of the existence of Density Wave order in these systems. Recent
evidence for strong Fermi surface nesting in superconducting $Cu-Bi_2Se_3$ and
$Nb-Bi_2Se_3$ has further led to speculation about the importance of charge
order in the context of unconventional superconductivity. Here, we report the
first observation of a novel anomaly in $Bi_2Se_3$ at 140K, which may be
associated with a Charge Density Wave (CDW)-like transition. This transition
was identified from both structural and electronic measurements, where: a) a
periodic lattice distortion at above room temperature was characterized as a
diffuse charge order in $Bi_2Se_3$ between \vec{k} and
\vec{k}\pm\mathrm{\Delta}\vec{k} from electron diffraction; and b) an opening
of energy gap signatured with metal-to-insulator like transition at 140K was
identified from resistivity vs temperature measurement. This is further
corroborated by nuclear magnetic resonance (NMR) studies of the spin-lattice
relaxation ( $\frac{1}{T_1}$) rate of the $^{209}Bi$ nucleus, which also
displays a transition at 140K associated with an opening of an energy gap of
~8meV. Additionally, we also observe another anomaly in $\frac{1}{T_1}$ near
200K, which appears to display anisotropy with the direction of the applied
magnetic field.",2002.12546v5
2021-06-14,Extreme mass-ratio inspirals around a spinning horizonless compact object,"Extreme mass-ratio inspirals (EMRIs) detectable by the Laser Interferometer
Space Antenna are unique probes of the nature of supermassive compact objects.
We compute the gravitational-wave signal emitted by a stellar-mass compact
object in a circular equatorial orbit around a Kerr-like horizonless
supermassive object defined by an effective radius and a reflectivity
coefficient. The Teukolsky equations are solved consistently with suitable
(frequency-dependent) boundary conditions, and the modified energy and
angular-momentum fluxes are used to evolve the orbital parameters
adiabatically. The gravitational fluxes have resonances corresponding to the
low-frequency quasinormal modes of the central object, which can contribute
significantly to the gravitational-wave phase. Overall, the absence of a
classical event horizon in the central object can affect the gravitational-wave
signal dramatically, with deviations even larger than those previously
estimated by a model-independent analysis of the tidal heating. We estimate
that EMRIs could potentially place the most stringent constraint on the
reflectivity of supermassive compact objects at the remarkable level of ${\cal
O}(10^{-6})\%$ and would allow to constrain various models which are not ruled
out by the ergoregion instability. In particular, an EMRI detection could allow
one to rule out (or provide evidence for) signatures of quantum black-hole
horizons with Boltzmann reflectivity. Our results provide motivation for
performing rigorous parameter estimation to assess the detectability of these
effects.",2106.07195v2
2013-11-25,Theory of nodal s+- wave pairing symmetry in the Pu-based 115 superconductor family,"The spin-fluctuation mechanism of superconductivity usually results in the
presence of gapless or nodal quasiparticle states in the excitation spectrum.
Nodal quasiparticle states are well established in copper-oxide, and
heavy-fermion superconductors, but not in iron-based superconductors. Here, we
study the pairing symmetry and mechanism of a new class of plutonium-based
high-Tc superconductors and predict the presence of a nodal $s^{+-}$ wave
pairing symmetry in this family. Starting from a density-functional theory
(DFT) based electronic structure calculation we predict several
three-dimensional (3D) Fermi surfaces in this 115 superconductor family. We
identify the dominant Fermi surface ``hot-spots' in the inter-band scattering
channel, which are aligned along the wavevector ${\bf Q}\sim(\pi,\pi,\pi)$,
where degeneracy could induce sign-reversal of the pairing symmetry. Our
calculation demonstrates that the $s^{+-}$ wave pairing strength is stronger
than the previously thought $d$-wave pairing; and more importantly, this
pairing state allows for the existence of nodal quasiparticles. Finally, we
predict the shape of the momentum- and energy-dependent magnetic resonance
spectrum for the identification of this pairing symmetry.",1311.6410v2
2007-10-03,Magnetic and Electric Excitations in Split Ring Resonators,"We studied the electric and magnetic resonance of U-shaped SRRs. We showed
that higher order excitation modes exist in both of the electric and magnetic
resonances. The nodes in the current distribution were found for all the
resonance modes. It turns out that the magnetic resonances are the modes with
odd-number of half-wavelength of the current wave, i.e. 1/2, 3/2 and 5/2
wavelengths modes, and the electric resonances are modes with integer number of
whole-wavelength of current wave, i.e. 1, 2 and 3 wavelengths modes. We
discussed the electric moment and magnetic moment of the electric and magnetic
resonances, and their dependence to the length of two parallel side arms. We
show that the magnetic moment of magnetic resonance vanishes as the length side
arms of the SRR reduces to zero, i.e. a rod does not give any magnetic moment
or magnetic resonance.",0710.0812v2
2017-05-16,Resonant lattice Kerker effect in metasurfaces with electric and magnetic optical responses,"To achieve efficient light control at subwavelength dimensions, plasmonic and
all-dielectric nanoparticles have been utilized both as a single element as
well as in the arrays. Here we study 2D periodic nanoparticle arrays
(metasurfaces) that support lattice resonances near the Rayleigh anomaly due to
the electric dipole (ED) and magnetic dipole (MD) resonant coupling between the
nanoparticles. Silicon and core-shell particles are considered. We demonstrate
for the first time that, choosing of lattice periods independently in each
mutual-perpendicular direction, it is possible to achieve a full overlap
between the ED-lattice resonance and MD resonances of nanoparticles in certain
spectral range and to realize the resonant lattice Kerker effect (resonant
suppression of the scattering or reflection). At the effect conditions, the
strong suppression of light reflectance in the structure is appeared due to
destructive interference between electromagnetic waves scattered by ED and MD
moments of every nanoparticle in the backward direction with respect to the
incident light wave. Influence of the array size on the revealed reflectance
and transmittance behavior is discussed. The resonant lattice Kerker effect
based on the overlap of both ED and MD lattice resonances is also demonstrated.",1705.05533v1
2020-07-22,Mathematical analysis of plasmon resonances for curved nanorods,"We investigate plasmon resonances for curved nanorods which present
anisotropic geometries. We analyze quantitative properties of the plasmon
resonance and its relationship to the metamaterial configurations and the
anisotropic geometries of the nanorods. Based on delicate and subtle asymptotic
and spectral analysis of the layer potential operators, particularly the
Neumann-Poincar\'e operators, associated with anisotropic geometries, we derive
sharp asymptotic formulae of the corresponding scattering field in the
quasi-static regime. By carefully analyzing the asymptotic formulae, we
establish sharp conditions that can ensure the occurrence of the plasmonic
resonance. The resonance conditions couple the metamaterial parameters, the
wave frequency and the nanorod geometry in an intricate but elegant manner. We
provide thorough resonance analysis by studying the wave fields both inside and
outside the nanorod. Furthermore, our quantitative analysis indicates that
different parts of the nanorod induce varying degrees of resonance.
Specifically, the resonant strength at the two end-parts of the curved nanorod
is more outstanding than that of the facade-part of the nanorod. This paper
presents the first theoretical study on plasmon resonances for nanostructures
within anisotropic geometries.",2007.11181v1
2020-10-24,Octave-Tunable Magnetostatic Wave YIG Resonators on a Chip,"We have designed, fabricated, and characterized magnetostatic wave (MSW)
resonators on a chip. The resonators are fabricated by patterning
single-crystal yttrium iron garnet (YIG) film on a gadolinium gallium garnet
(GGG) substrate and excited by loop-inductor transducers. We achieved this
technology breakthrough by developing a YIG film etching process and
fabricating thick aluminum coplanar waveguide (CPW) inductor loop around each
resonator to individually address and excite MSWs. At 4.77 GHz, the 0.68 square
mm resonator achieves a quality factor Q > 5000 with a bias field of 987 Oe. We
also demonstrate YIG resonator tuning by more than one octave from 3.63 to 7.63
GHz by applying an in-plane external magnetic field. The measured quality
factor of the resonator is consistently over 3000 above 4 GHz. The
micromachining technology enables the fabrication of multiple single- and
two-port YIG resonators on the same chip with all resonators demonstrating
octave tunability and high Q .",2010.12732v1
2021-09-03,Probing double hadron resonances by the complex scaling method,"Many newly discovered excited states are interpreted as bound states of
hadrons. Can these hadrons also form resonant states? In this paper, we extend
the complex scaling method (CSM) to calculate the bound state and resonant
state consistently for the $\Lambda_c D(\bar D)$ and $\Lambda_c \Lambda_c (\bar
\Lambda_c)$ systems. For these systems, the $\pi, \eta, \rho$ meson exchange
contributions are suppressed, the contributions of intermediate- and
short-range forces from $\sigma/\omega$ exchange are dominant. Our results
indicate that $\Lambda_c D$ system can not form bound state and resonant state.
There exist resonant states in a wide range of parameters for $\Lambda_c \bar
D$ and $\Lambda_c \Lambda_c (\bar \Lambda_c)$ systems. For these systems, the
larger bound state energy, the easier to form resonant states. Among all the
resonant states, the energies and widths of the P wave resonant states are
smaller and more stable, which is possible to be observed in the experiments.
The energies of D and F wave resonant states can reach dozens of MeV and the
widths can reach hundreds of MeV.",2109.01259v1
2023-07-16,Controlling periodic Fano resonances of quantum acoustic waves with a giant atom coupled to microwave waveguide,"Nanoscale Fano resonances, with applications from telecommunications to
ultra-sensitive biosensing, have prompted extensive research. We demonstrate
that a superconducting qubit, jointly coupled to microwave waveguides and an
inter-digital transducer composite device, can exhibit acoustic Fano
resonances. Our analytical framework, leveraging the Taylor series
approximation, elucidates the origins of these quantum acoustic resonances with
periodic Fano-like interference. By analyzing the analytical Fano parameter, we
demonstrate that the Fano resonances and their corresponding Fano widths near
the resonance frequency of a giant atom can be precisely controlled and
manipulated by adjusting the time delay. Moreover, not just the near-resonant
Fano profiles, but the entire periodic Fano resonance features can be precisely
modulated from Lorentz, Fano to quasi-Lorentz shapes by tuning the coupling
strength of the microwave waveguide. Our analytical framework offers insights
into the control and manipulation of periodic Fano resonances in quantum
acoustic waves, thereby presenting significant potential for applications such
as quantum information processing, sensing, and communication.",2307.07949v1
2016-05-10,Controlling Spin-Polarization in Graphene by Cloaking Magnetic and Spin-Orbit Scatterers,"We consider spin-dependent scatterers with large scattering cross-sections in
graphene -a Zeeman-like and an intrinsic spin-orbit coupling impurity- and show
that a gated ring around them can be engineered to produce an effcient control
of the spin dependent transport, like current spin polarization and spin Hall
angle. Our analysis is based on a spin-dependent partial-waves expansion of the
electronic wave-functions in the continuum approximation, described by the
Dirac equation.",1605.02814v2
1999-03-05,SC state in the underdoped high-T_c cuprates as a quantum spin liquid. A microscopic theory,"We have discovered a new example of quantum spin liquid which is a
superconducting (SC) phase in 2D electron system close to electronic
topological transition. As a quantum spin liquid in low dimensional localized
spin systems it is characterized by a resonance spin mode and a well separated
two-particle continuum. Application of the theory to the high-T_c cuprates
allows to shed light on many observed in the underdoped regime features such as
the so called 40 meV resonance peak, incommensurability at lower \omega, spin
gap etc.",9903097v1
2002-12-02,Resonant spin current in nanotube double junctions,"Zero bias conductance per spin of nanotube double junction (NTDJ) is
investigated theoretically using the tight binding model, unrestricted
Hartree-Fock approximation and non-equilibrium Green's functions.
  NTDJ consists of two metallic nanotubes joined by a piece of semiconducting
nanotube, with the transition between the nanotubes made up of sets of 5 and 7
member carbon rings.
  A quantum well forms in the central semiconducting NT region, bounded by
Schottky barriers.
  Spin current occurs when Coulomb interactions raise the spin degeneracy of
resonant levels in the quantum well.
  As long as an appropriate semiconducting NT length is chosen, spin direction
can be controlled by gate voltage, i.e., NTDJ functions as a nano spin filter.",0212021v1
2009-09-01,Enhanced spin Hall effect by tuning antidot potential: Proposal for a spin filter,"We propose an efficient spin filter including an antidot fabricated on
semiconductor heterostructures with strong spin-orbit interaction. The antidot
creates a tunable potential on two-dimensional electron gas in the
heterostructures, which may be attractive as well as repulsive. Our idea is
based on the enhancement of extrinsic spin Hall effect by resonant scattering
when the attractive potential is properly tuned. Numerical studies for three-
and four-terminal devices indicate that the efficiency of the spin filter can
be more than 50% by tuning the potential to the resonant condition.",0909.0150v1
2010-01-21,Spin Dependent Joule Heating due to Rashba Coupling and Zitterbewegung,"Investigating microwave absorption in asymmetric Si quantum wells in an
external magnetic field, we discover a spin dependent component of Joule
heating at spin resonance. We explain this effect in terms of Rashba spin-orbit
coupling which results in a current induced spin precession and Zitterbewegung.
Evidence is based on the observation of a specific dependence of the electron
spin resonance line shape and its amplitude on the experimental geometry which
in some range suggests a ""negative"" differential power absorption.",1001.3746v2
2012-08-06,Probing the superconducting pairing symmetry from spin excitations in BiS$_2$ based superconductors,"Starting from a two-orbital model and based on the random phase
approximation, spin excitations in the superconducting state of the newly
discovered BiS$_2$ superconductors with three possible pairing symmetries are
studied theoretically. We show that spin response is uniquely determined by the
pairing symmetry. Possible spin resonance excitations might occur for the
d-wave symmetry at an incommensurate momentum about $(0.7\pi,0.7\pi)$. For the
p-wave symmetry the transverse spin excitation near $(0,0)$ is enhanced. For
the s-wave pairing symmetry there is no spin resonance signature. These
distinct features may be used for probing or determining the pairing symmetry
in this newly discovered compound.",1208.1101v1
2019-05-21,"Extreme nuclear magnetic resonance: zero field, single spins, dark matter...","An unusual regime for liquid-state nuclear magnetic resonance (NMR) where the
magnetic field strength is so low that the $J$-coupling (intramolecular
spin-spin) interactions dominate the spin Hamiltonian opens a new paradigm with
applications in spectroscopy, quantum control, and in fundamental-physics
experiments, including searches for well-motivated dark-matter candidates. An
interesting possibility is to bring this kind of ""extreme NMR"" together with
another one---single nuclear spin detected with a single-spin quantum sensor.
This would enable single-molecule $J$-spectroscopy.",1905.08851v1
2009-08-04,Non-equilibrium Spin Waves in Paramagnetic Metals,"We theoretically study the effect of exchange interaction on the
non-equilibrium spin waves in disordered paramagnetic metals under the spin
injection condition. We show that the gapless spectrum of spin waves,
describing the spin precession in the absence of the applied magnetic field,
changes sign to negative on the paramagnetic side near the ferromagnet -
paramagnet phase transition. The damping of spin waves is small in the limit
when electron-electron exchange energy is larger than the inverse electron mean
free time, while in the opposite limit the propagation of spin waves is
strongly suppressed. We discuss the amplification of the electromagnetic field
by the non-equilibrium spin waves.",0908.0466v2
2016-02-12,Internal dipolar field and soft magnons in periodic nanocomposite magnets,"We study spin wave excitations in a three-dimensional nanocomposite magnet of
exchange coupled hard (SmCo$_5$) and soft (FeCo) phases. The dipolar
interaction splits the spin wave energies into the upper and lower branches of
the spin wave manifold. When the amount of the soft phase is increased the
energy of low-lying spin excitations is considerably softened due to two
reasons: (i) the low- lying mode locked into the soft phase region with a spin
wave gap at ${\bf k}= 0$ which scales approximately proportional to the
anisotropy constant of the soft phase and (ii) the internal dipolar field which
comes from magnetic charges forming at hard-soft boundaries with normals
parallel to the magnetization displaces the spin wave manifold toward the lower
energies. With adding more soft phase the spin wave gap closes and the system
moves to another ground state characterized by the magnetization mismatch
between spins of the hard and soft phases.",1602.04111v1
2017-12-22,Nanomagnonic waveguides based on reconfigurable spin-textures for spin computing,"Magnonics is gaining momentum as an emerging technology for information
processing. The wave character and Joule heating-free propagation of spin-waves
hold promises for highly efficient analog computing platforms, based on
integrated magnonic circuits. Miniaturization is a key issue but, so far, only
few examples of manipulation of spin-waves in nanostructures have been
demonstrated, due to the difficulty of tailoring the nanoscopic magnetic
properties with conventional fabrication techniques. In this Letter, we
demonstrate an unprecedented degree of control in the manipulation of
spin-waves at the nanoscale by using patterned reconfigurable spin-textures. By
space and time-resolved scanning transmission X-ray microscopy imaging, we
provide direct evidence for the channeling and steering of propagating
spin-waves in arbitrarily shaped nanomagnonic waveguides based on patterned
domain walls, with no need for external magnetic fields or currents.
Furthermore, we demonstrate a prototypic nanomagnonic circuit based on two
converging waveguides, allowing for the tunable spatial superposition and
interaction of confined spin-waves modes.",1712.08293v1
2018-05-03,Sculpting the Spin-Wave Response of Artificial Spin Ice via Microstate Selection,"The spin-wave dynamics of the ferromagnetic nanoarrays termed artificial spin
ice (ASI) are known to vary depending on their magnetic microstate. However,
little work has been done to characterise this relationship. Recent advances in
control over the magnetic configuration of ASI bring designs harnessing the
interplay between spin-wave eigenmodes and the microstate within reach,
offering diverse applications including reconfigurable magnonic crystals,
microwave filters and microstate read-out probes. These designs hinge on a
strong understanding of the underlying spin wave-microstate correspondence.
  Here, we analyse the effects of the magnetic microstate on spin-wave spectra
of honeycomb ASI systems via micromagnetic simulation. We find the spin-wave
spectrum to be highly-tunable via the microstate to an enhanced degree relative
to existing magnonic crystals, with mode shifting and (de)activation realised
by reversing individual nanoislands. Symmetries of ASI systems and the
chirality of magnetic defects are found to play important roles in determining
the high-frequency response.",1805.01397v3
2021-04-21,Spin-wave driven bidirectional domain wall motion in kagome antiferromagnets,"We predict a mechanism to controllably manipulate domain walls in kagome
antiferromagnets via a single linearly polarized spin-wave source. We show by
means of atomistic spin dynamics simulations of antiferromagnets with kagome
structure that the speed and direction of the domain wall motion can be
regulated by only tuning the frequency of the applied spin-wave. Starting from
microscopics, we establish an effective action and derive the corresponding
equations of motion for the spin-wave-driven domain wall. Our analytical
calculations reveal that the coupling of two spin-wave modes inside the domain
wall explains the frequency-dependent velocity of the spin texture. Such a
highly tunable spin-wave-induced domain wall motion provides a key component
toward next-generation fast, energy-efficient, and Joule-heating-free
antiferromagnetic insulator devices.",2104.10460v2
2006-04-13,"Direct observation of a ""devil's staircase'' in wave-particle interaction","We report the experimental observation of a ""devil's staircase'' in a time
dependent system considered as a paradigm for the transition to large scale
chaos in the universality class of hamiltonian systems. A test electron beam is
used to observe its non-self-consistent interaction with externally excited
wave(s) in a Travelling Wave Tube (TWT). A trochoidal energy analyzer records
the beam energy distribution at the output of the interaction line. An
arbitrary waveform generator is used to launch a prescribed spectrum of waves
along the slow wave structure (a 4 m long helix) of the TWT. The resonant
velocity domain associated to a single wave is observed, as well as the
transition to large scale chaos when the resonant domains of two waves and
their secondary resonances overlap. This transition exhibits a ""devil's
staircase'' behavior for increasing excitation amplitude, due to the nonlinear
forcing by the second wave on the pendulum-like motion of a charged particle in
one electrostatic wave.",0604029v2
2007-08-14,Shock Waves in Nanomechanical Resonators,"The dream of every surfer is an extremely steep wave propagating at the
highest speed possible. The best waves for this would be shock waves, but are
very hard to surf. In the nanoscopic world the same is true: the surfers in
this case are electrons riding through nanomechanical devices on acoustic waves
[1]. Naturally, this has a broad range of applications in sensor technology and
for communication electronics for which the combination of an electronic and a
mechanical degree of freedom is essential. But this is also of interest for
fundamental aspects of nano-electromechanical systems (NEMS), when it comes to
quantum limited displacement detection [2] and the control of phonon number
states [3]. Here, we study the formation of shock waves in a NEMS resonator
with an embedded two-dimensional electron gas using surface acoustic waves. The
mechanical displacement of the nano-resonator is read out via the induced
acoustoelectric current. Applying acoustical standing waves we are able to
determine the anomalous acoustocurrent. This current is only found in the
regime of shock wave formation. We ontain very good agreement with model
calculations.",0708.1799v1
2015-10-03,Multiscale Asymptotics for the Skeleton of the Madden-Julian Oscillation and Tropical-Extratropical Interactions,"A new model is derived and analyzed for tropical-extratropical interactions
involving the Madden-Julian oscillation (MJO). The model combines (i) the
tropical dynamics of the MJO and equatorial baroclinic waves and (ii) the
dynamics of barotropic Rossby waves with significant extratropical structure,
and the combined system has a conserved energy. The method of multiscale
asymptotics is applied to systematically derive a system of ordinary
differential equations (ODEs) for three-wave resonant interactions. Two novel
features are (i) a degenerate auxiliary problem with overdetermined equations
due to a compatibility condition (meridional geostrophic balance) and (ii)
cubic self-interaction terms that are not typically found in three-wave
resonance ODEs. Several examples illustrate applications to MJO initiation and
termination, including cases of (i) the MJO, equatorial baroclinic Rossby
waves, and barotropic Rossby waves interacting, and (ii) the MJO, baroclinic
Kelvin waves, and barotropic Rossby waves interacting. Resonance with the
Kelvin wave is not possible here if only dry variables are considered, but it
occurs in the moist model here through interactions with water vapor and
convective activity.",1510.00881v3
2016-01-21,Detection of spin pumping from YIG by spin-charge conversion in a Au/Ni$_{80}$Fe$_{20}$ spin-valve structure,"Many experiments have shown the detection of spin-currents driven by
radio-frequency spin pumping from yttrium iron garnet (YIG), by making use of
the inverse spin-Hall effect, which is present in materials with strong
spin-orbit coupling, such as Pt. Here we show that it is also possible to
directly detect the resonance-driven spin-current using Au/permalloy (Py,
Ni$_{80}$Fe$_{20}$) devices, where Py is used as a detector for the spins
pumped across the YIG/Au interface. This detection mechanism is equivalent to
the spin-current detection in metallic non-local spin-valve devices. By finite
element modeling we compare the pumped spin-current from a reference Pt strip
with the detected signals from the Au/Py devices. We find that for one series
of Au/Py devices the calculated spin pumping signals mostly match the
measurements, within 20%, whereas for a second series of devices additional
signals are present which are up to a factor 10 higher than the calculated
signals from spin pumping. We also identify contributions from thermoelectric
effects caused by the resonant (spin-related) and non-resonant heating of the
YIG. Thermocouples are used to investigate the presence of these thermal
effects and to quantify the magnitude of the Spin-(dependent-)Seebeck effect.
Several additional features are observed, which are also discussed.",1601.05605v1
2019-08-05,Spin inertia and polarization recovery in quantum dots: Role of pumping strength and resonant spin amplification,"Spin inertia measurements are a novel experimental tool to study long-time
spin relaxation processes in semiconductor nanostructures. We develop a theory
of the spin inertia effect for resident electrons and holes localized in
quantum dots. We consider the spin orientation by short optical pulses with
arbitrary pulse area and detuning from the trion resonance. The interaction
with an external longitudinal magnetic field and the hyperfine interaction with
the nuclear spin bath is considered in both the ground and excited (trion)
states of the quantum dots. We analyze how the spin inertia signal depends on
the magnetic field (polarization recovery) and on the modulation frequency of
the helicity of the pump pulses as well as on their power and detuning. In
particular, we elaborate how approaching the saturation limit of the spin
polarization influences the measurements. The quantitative description of spin
inertia measurements will enable the determination of the parameters of spin
dynamics such as the spin relaxation times in the ground and excited states and
the parameters of the hyperfine interaction. Finally, we predict the emergence
of resonant spin amplification due to the transverse components of the nuclear
spin fluctuations, which manifests itself as oscillations of the spin
polarization as a function of the longitudinal magnetic field.",1908.01531v3
2015-01-26,Decoherent time-dependent transport beyond the Landauer-Büttiker formulation: a quantum-drift alternative to quantum jumps,"We present a model for decoherence in time-dependent transport. It boils down
into a form of wave function that undergoes a smooth stochastic drift of the
phase in a local basis, the Quantum Drift (QD) model. This drift is nothing
else but a local energy fluctuation. Unlike Quantum Jumps (QJ) models, no jumps
are present in the density as the evolution is unitary. As a first application,
we address the transport through a resonant state $\left\vert 0\right\rangle $
that undergoes decoherence. We show the equivalence with the decoherent steady
state transport in presence of a B\""{u}ttiker's voltage probe. In order to test
the dynamics, we consider two many-spin systems whith a local energy
fluctuation. A two-spin system is reduced to a two level system (TLS) that
oscillates among $\left\vert 0\right\rangle $ $\equiv $ $ \left\vert \uparrow
\downarrow \right\rangle $ and $\left\vert 1\right\rangle \equiv $ $\left\vert
\downarrow \uparrow \right\rangle $. We show that QD model recovers not only
the exponential damping of the oscillations in the low perturbation regime, but
also the non-trivial bifurcation of the damping rates at a critical point, i.e.
the quantum dynamical phase transition. We also address the spin-wave like
dynamics of local polarization in a spin chain. The QD average solution has
about half the dispersion respect to the mean dynamics than QJ. By evaluating
the Loschmidt Echo (LE), we find that the pure states $\left\vert
0\right\rangle $ and $\left\vert 1\right \rangle $ are quite robust against the
local decoherence. In contrast, the LE, and hence coherence, decays faster when
the system is in a superposition state. Because its simple implementation, the
method is well suited to assess decoherent transport problems as well as to
include decoherence in both one-body and many-body dynamics.",1501.06610v2
2017-05-29,Dynamic pathway of the photoinduced phase transition of TbMnO$_3$,"We investigate the demagnetization dynamics of the cycloidal and sinusoidal
phases of multiferroic TbMnO$_3$ by means of time-resolved resonant soft x-ray
diffraction following excitation by an optical pump. Using orthogonal linear
x-ray polarizations, we suceeded in disentangling the response of the
multiferroic cycloidal spin order from the sinusoidal antiferromagnetic order
in the time domain. This enables us to identify the transient magnetic phase
created by intense photoexcitation of the electrons and subsequent heating of
the spin system on a picosecond timescale. The transient phase is shown to be a
spin density wave, as in the adiabatic case, which nevertheless retains the
wave vector of the cycloidal long range order. Two different pump photon
energies, 1.55 eV and 3.1 eV, lead to population of the conduction band
predominantly via intersite $d$-$d$ transitions or intrasite $p$-$d$
transitions, respectively. We find that the nature of the optical excitation
does not play an important role in determining the dynamics of magnetic order
melting. Further, we observe that the orbital reconstruction, which is induced
by the spin ordering, disappears on a timescale comparable to that of the
cycloidal order, attesting to a direct coupling between magnetic and orbital
orders. Our observations are discussed in the context of recent theoretical
models of demagnetization dynamics in strongly correlated systems, revealing
the potential of this type of measurement as a benchmark for such complex
theoretical studies.",1705.10136v1
2019-06-04,Torque equilibrium spin wave theory study of anisotropy and Dzyaloshinskii-Moriya interaction effects on the indirect K$-$ edge RIXS spectrum of a triangular lattice antiferromagnet,"We apply the recently formulated torque equilibrium spin wave theory (TESWT)
to compute the $1/S$-order interacting $K$ -edge bimagnon resonant inelastic
x-ray scattering (RIXS) spectra of an anisotropic triangular lattice
antiferromagnet with Dzyaloshinskii-Moriya (DM) interaction. We extend the
interacting torque equilibrium formalism, incorporating the effects of DM
interaction, to appropriately account for the zero-point quantum fluctuation
that manifests as the emergence of spin Casimir effect in a noncollinear spin
spiral state. Using inelastic neutron scattering data from Cs$_2$CuCl$_4$ we
fit the 1/S corrected TESWT dispersion to extract exchange and DM interaction
parameters. We use these new fit coefficients alongside other relevant model
parameters to investigate, compare, and contrast the effects of spatial
anisotropy and DM interaction on the RIXS spectra at various points across the
magnetic Brillouin zone. We highlight the key features of the bi- and trimagnon
RIXS spectrum at the two inequivalent rotonlike points, $M(0,2 \pi/\sqrt{3})$
and $M^{\prime}(\pi,\pi/\sqrt{3})$, whose behavior is quite different from an
isotropic triangular lattice system. While the roton RIXS spectrum at the $M$
point undergoes a spectral downshift with increasing anisotropy, the peak at
the $M^\prime$ location loses its spectral strength without any shift. With the
inclusion of DM interaction the spiral phase is more stable and the peak at
both $M$ and $M^\prime$ point exhibits a spectral upshift. Our calculation
offers a practical example of how to calculate interacting RIXS spectra in a
non-collinear quantum magnet using TESWT. Our findings provide an opportunity
to experimentally test the predictions of interacting TESWT formalism using
RIXS, a spectroscopic method currently in vogue.",1906.01619v3
2003-11-11,Spin-resonance modes of the spin-gap magnet TlCuCl_3,"Three kinds of magnetic resonance signals were detected in crystals of the
spin-gap magnet TlCuCl_3.
  First, we have observed the microwave absorption due to the excitation of the
transitions between the singlet ground state and the excited triplet states.
This mode has the linear frequency-field dependence corresponding to the
previously known value of the zero-field spin-gap of 156 GHz and to the closing
of spin-gap at the magnetic field H_c of about 50 kOe.
  Second, the thermally activated resonance absorption due to the transitions
between the spin sublevels of the triplet excitations was found. These
sublevels are split by the crystal field and external magnetic field.
  Finally, we have observed antiferromagnetic resonance absorption in the
field-induced antiferromagnetic phase above the critical field H_c. This
resonance frequency is strongly anisotropic with respect to the direction of
the magnetic field.",0311243v2
1994-02-17,On The $Q^2$ Dependence of The Spin Structure Function In The Resonance Region,"In this paper, we show what we can learn from the CEBAF experiments on
spin-structure functions, and the transition from the Drell-Hearn-Gerasimov sum
rule in the real photon limit to the spin dependent sum rules in the deep
inelastic scattering, and how the asymmetry $A_1(x,Q^2)$ approaches the scaling
limit in the resonance region. The spin structure function in the resonance
region alone can not determine the spin-dependent sum rule due to the kinematic
restriction of the resonance region. The integral $\int_0^1 \frac
{A_1(x,Q^2)F_2(x,Q^2)}{2x(1+R(x,Q^2))}dx$ is estimated from $Q^2=0$ to $2.5$
GeV$^2$. The result shows that there is a region where both contributions from
the baryon resonances and the deep inelastic scattering are important, thus
provides important information on the high twist effects on the spin dependent
sum rule.",9402308v1
2013-02-28,First-principles calculations of spin and angle-resolved resonant photoemission spectra of Cr(110) surfaces at the 2$p$ - 3$d$ resonance,"A first principles approach for spin and angle resolved resonant
photoemission is developed within multiple scattering theory and applied to a
Cr(110) surface at the 2$p$-3$d$ resonance. The resonant photocurrent from this
non ferromagnetic system is found to be strongly spin polarized by circularly
polarized light, in agreement with experiments on antiferromagnetic and
magnetically disordered systems. By comparing the antiferromagnetic and
Pauli-paramagnetic phases of Cr, we explicitly show that the spin polarization
of the photocurrent is independent of the existence of local magnetic moments,
solving a long-standing debate on the origin of such polarization. New spin
polarization effects are predicted for the paramagnetic phase even with
unpolarized light, opening new directions for full mapping of spin interactions
in macroscopically non magnetic or nanostructured systems.",1302.7160v1
2018-05-15,Microwave dual-mode resonators for coherent spin-photon coupling,"We implement superconducting YBCO planar resonators with two fundamental
modes for circuit quantum electrodynamics experiments. We first demonstrate
good tunability in the resonant microwave frequencies and in their interplay as
it emerges from the dependence of the transmission spectra on the device
geometry. We then investigate the magnetic coupling of the resonant modes with
bulk samples of DPPH organic radical spins. The transmission spectroscopies
performed at low temperature show that the coherent spin-photon coupling regime
with the spin ensembles can be achieved by each of the resonator modes. The
analysis of the results within the framework of the Input-Output formalism and
by means of entropic measures demonstrates coherent mixing of the degrees of
freedom corresponding to two remote spin ensembles and, with a suitable choice
of the geometry, the approaching of a regime with spin-induced mixing of the
two photon modes.",1805.05843v3
2021-04-29,Bulk-Sensitive Spin-Resolved Resonant Electron Energy-Loss Spectroscopy (SR-rEELS): Observation of Element- and Spin-Selective Bulk Plasmons,"We have developed a spin-resolved resonant electron energy-loss spectroscopy
(SR-rEELS) in the primary energy of 0.3--1.5 keV, which corresponds to the core
excitations of $2p$-$3d$ absorption of transition metals and $3d$-$4f$
absorption of rare-earths, with the energy resolution of about 100~meV using a
spin-polarized electron source as a GaAs/GaAsP strained superlattice
photocathode. Element- and spin-selective carrier and valence plasmons can be
observed using the resonance enhancement of core absorptions and electron spin
polarization. Furthermore, bulk-sensitive EELS spectra can be obtained because
the primary energy corresponds to the mean free path of 1--10~nm. The
methodology is expected to provide us novel information of elementary
excitations by resonant inelastic x-ray scattering and resonant photoelectron
spectroscopy.",2104.14262v2
2008-06-23,Strong magnetic coupling between an electronic spin qubit and a mechanical resonator,"We describe a technique that enables a strong, coherent coupling between a
single electronic spin qubit associated with a nitrogen-vacancy impurity in
diamond and the quantized motion of a magnetized nano-mechanical resonator tip.
This coupling is achieved via careful preparation of dressed spin states which
are highly sensitive to the motion of the resonator but insensitive to
perturbations from the nuclear spin bath. In combination with optical pumping
techniques, the coherent exchange between spin and motional excitations enables
ground state cooling and the controlled generation of arbitrary quantum
superpositions of resonator states. Optical spin readout techniques provide a
general measurement toolbox for the resonator with quantum limited precision.",0806.3606v1
2020-05-14,Impurity-induced resonant spinon zero modes in Dirac quantum spin-liquids,"Quantum spin-liquids are strongly correlated phases of matter displaying a
highly entangled ground state. Due to their unconventional nature, finding
experimental signatures of these states has proven to be a remarkable
challenge. Here we show that the effects of local impurities can provide strong
signatures of a Dirac quantum spin-liquid state. Focusing on a gapless Dirac
quantum spin-liquid state as realized in NaYbO$_2$, we show that single
magnetic impurity coupled to the quantum spin-liquid state creates a resonant
spinon peak at zero frequency, coexisting the original Dirac spinons. We
explore the spatial dependence of this zero-bias resonance, and show how
different zero modes stemming from several impurities interfere. We finally
address how such spinon zero-mode resonances can be experimentally probed with
inelastic spectroscopy and electrically-driven paramagnetic resonance with
scanning tunnel microscopy. Our results put forward impurity engineering as a
means of identifying Dirac quantum spin-liquids with scanning probe techniques,
highlighting the dramatic impact of magnetic impurities in a macroscopically
entangled many-body ground state.",2005.06896v2
1999-08-26,Lepton -Neutron Bound States,"We consider lepton-neutron (and lepton-antineutron) bound states and
resonances which appear due to spin-spin, spin-orbital interactions,neutron
polarization by muon. Our analis is also true for any system which include one
charge and one neutral particle with finite size e.g. $\pi^0\mu^{\pm}$-bound
states.We consider also cylindrically symmetric bound states and resonances of
particles with anomalous magnetic moments.",9908478v2
1995-08-02,Spin-dependent resonant tunneling through semimetallic ErAs quantum wells,"Resonant tunneling through semimetallic ErAs quantum wells embedded in GaAs
structures with AlAs barriers was recently found to exhibit an intriguing
behavior in magnetic fields which is explained in terms of tunneling selection
rules and the spin-polarized band structure including spin-orbit coupling.",9508003v1
1999-09-21,Spin Alignments in Heavy-ion Resonances,"Recent particle-particle-$\gamma$ coincident measurements on a $^{28}\rm
Si+{}^{28}Si$ resonance have suggested ''vanishing spin alignments''. New
analyses for spin alignments by using a molecular model are reported. Different
aspects between di-nuclear systems with prolate deformed nuclei and those with
oblate deformed nuclei are clarified.",9909056v1
2004-05-24,Spin Microscope Based on Optically Detected Magnetic Resonance,"We propose a scanning magnetic microscope which has a photoluminescence
nanoprobe implanted in the tip of an AFM or STM, or NSOM, and exhibits
optically detected magnetic resonance (ODMR). The proposed spin microscope has
nanoscale lateral resolution and the single spin sensitivity for AFM and STM.",0405143v1
2013-12-29,The spin-orbit resonances of the Solar system: A mathematical treatment matching physical data,"In the mathematical framework of a restricted, slightly dissipative
spin-orbit model, we prove the existence of periodic orbits for astronomical
parameter values corresponding to all satellites of the Solar system observed
in exact spin-orbit resonance.",1312.7544v1
2014-03-06,Influence of the Dzyaloshinskii-Moriya interaction on the spin-torque diode effect,"This paper predicts the effect of the Dzyaloshinskii-Moriya interaction (DMI)
and spin Hall effect in the spin-torque diode response of a Magnetic Tunnel
Junction built over a Tantalum strip. Our results indicate that, for a
microwave current large enough, the DMI can change qualitatively the resonant
response by splitting the ferromagnetic resonance peak. We also find out that
the two modes have a non-uniform spatial distribution.",1403.1485v1
2019-11-04,Fano resonance in metallic grating via strongly coupled subwavelength resonators,"We investigate the Fano resonance in grating structures by using coupled
resonators. The grating consists of a perfectly conducting slab with
periodically arranged subwavelength slit holes, where inside each period, a
pair of slits sit very close to each other. The slit holes act as resonators
and are strongly coupled. It is shown rigorously that there exist two groups of
resonances corresponding to poles of the scattering problem. One sequence of
resonances have imaginary part on the order of $\varepsilon$, where
$\varepsilon$ is the size of the slit aperture, while the other sequence have
imaginary part on the order of $\varepsilon^2$. When coupled with the incident
wave at resonant frequencies, the narrow-band resonant scattering induced by
the latter will interfere with the broader background resonant radiation
induced by the former. The interference of these two resonances generates the
Fano type transmission anomaly, which persists in the whole radiation continuum
of the grating structure as long as the slit aperture size is small compared to
the incident wavelength.",1911.01025v2
2023-03-28,Characterization of harmonic modes and parasitic resonances in multi-mode superconducting coplanar resonators,"Planar superconducting microwave transmission line resonators can be operated
at multiple harmonic resonance frequencies. This allows covering wide spectral
regimes with high sensitivity, as it is desired e.g. for cryogenic microwave
spectroscopy. A common complication of such experiments is the presence of
undesired 'spurious' additional resonances, which are due to standing waves
within the resonator substrate or housing box. Identifying the nature of
individual resonances ('designed' vs. 'spurious') can become challenging for
higher frequencies or if elements with unknown material properties are
included, as is common for microwave spectroscopy. Here we discuss various
experimental strategies to distinguish designed and spurious modes in coplanar
superconducting resonators that are operated in a broad frequency range up to
20 GHz. These strategies include tracking resonance evolution as a function of
temperature, magnetic field, and microwave power. We also demonstrate that
local modification of the resonator, by applying minute amounts of dielectric
or ESR-active materials, lead to characteristic signatures in the various
resonance modes, depending on the local strength of the electric or magnetic
microwave fields.",2303.15914v1
2023-11-29,Velocity Space Signatures of Resonant Energy Transfer between Whistler Waves and Electrons in the Earth's Magnetosheath,"Wave--particle interactions play a crucial role in transferring energy
between electromagnetic fields and charged particles in space and astrophysical
plasmas. Despite the prevalence of different electromagnetic waves in space,
there is still a lack of understanding of fundamental aspects of wave--particle
interactions, particularly in terms of energy flow and velocity-space
characteristics. In this study, we combine a novel quasilinear model with
observations from the Magnetospheric Multiscale (MMS) mission to reveal the
signatures of resonant interactions between electrons and whistler waves in
magnetic holes, which are coherent structures often found in the Earth's
magnetosheath. We investigate the energy transfer rates and velocity-space
characteristics associated with Landau and cyclotron resonances between
electrons and slightly oblique propagating whistler waves. In the case of our
observed magnetic hole, the loss of electron kinetic energy primarily
contributes to the growth of whistler waves through the $n=-1$ cyclotron
resonance, where $n$ is the order of the resonance expansion in linear
Vlasov--Maxwell theory. The excitation of whistler waves leads to a reduction
of the temperature anisotropy and parallel heating of the electrons. Our study
offers a new and self-consistent understanding of resonant energy transfer in
turbulent plasmas.",2311.17309v1
2020-04-05,Resonant high-energy bremsstrahlung of ultrarelativistic electrons in the field of a nucleus and a pulsed light wave,"The actual theoretical research investigates the resonant high-energy
spontaneous bremsstrahlung of ultrarelativistic electrons with considerable
energies in the field of a nucleus and a quasimonochromatic laser wave. Under
the resonant conditions within the laser field the intermediate virtual
electron transforms into the real particle. As a result, the accomplished
analysis defines that the polar emission angle characterizes the frequency of a
spontaneous photon. The study derives the expressions for the resonant
differential cross-sections of the represented processes that realize
simultaneous registration of the frequency and radiation angle in correlation
to the momentum of the initial electron (for the channel A) and of the final
electron (for the channel B) of the spontaneous photon with absorption of $r$
wave photons ($r = 1, 2, 3,... $ - the number of a resonance). Additionally,
the distribution of the resonant differential cross-section as a function of
the angle of the spontaneous photon emission for the higher numbers of
resonance ($r = 2, 3,... $) delineates a dependency with a sharp peak maximum
that coordinates to the particle radiation at the most probable frequency. To
summarize, the accomplished work represents that the resonant differential
cross-section acquires considerable magnitude. Thus, for the first resonance of
the channel A the resonant differential cross-section attains the $\sim
10^{12}$ order of a magnitude, and for the third resonance of the channel B
$\sim 10^5$ order of a magnitude (in the units of $\alpha Z^2 r_e^2$). Finally,
numerous scientific facilities with specialization in pulsed laser radiation
(SLAC, FAIR, XFEL, ELI, XCELS) may experimentally verify the constructed model
calculations.",2004.02247v1
2019-08-30,Dynamical generation of resonances in the P33 partial wave,"We investigate the formation of resonances in the P33 partial wave with the
emphasis on possible emergence of dynamically generated quasi-bound states as a
consequence of a strong $p$-wave pion attractive interaction in this partial
wave, as well as their possible interaction with the genuine quark excited
states. By using the Laurent-Pietarinen expansion we follow the evolution of
the $S$-matrix poles in the complex energy plane as a function of the
interaction strength. Already without introducing a genuine quark resonant
state, two physically interesting resonances emerge with pole masses around
1200 MeV and 1400 MeV, with the dominant $\pi N$ and $\pi\Delta$ component,
respectively. The added genuine resonant state in the $(1s)^3$ quark
configuration mixes with the lower dynamically generated resonance forming the
physical $\Delta(1232)$ resonance, and pushes the second dynamical resonance to
around 1500 MeV, which allows it to be identified with the $\Delta(1600)$
resonance. Adding a second resonant state with one quark promoted to the $2s$
orbit generates another pole whose evolution remains well separated from the
lower two poles. We calculate the helicity amplitudes at the pole and suggest
that their $Q^2$ dependence could be a decisive test to discriminate between
different models of the $\Delta(1600)$ resonance.",1908.11750v1
2006-09-11,Spin Waves in Ultrathin Ferromagnets: Intermediate Wave Vectors,"Our earlier papers explore the nature of large wave vector spin waves in
ultrathin ferromagnets, and also the properties and damping of spin waves of
zero wave vector, at the center of the two dimensional Brillouin zone, with
application to FMR studies. The present paper explores the behavior of spin
waves in such films at intermediate wave vectors, which connect the two
regimes. For the case of Fe films on Au(100), we study the wave vector
dependence of the linewidth of the lowest frequency mode, to find that it
contains a term which varies as the fourth power of the wave vector. It is
argued that this behavior is expected quite generally. We also explore the
nature of the eigenvectors of the two lowest lying modes of the film, as a
function of wave vector. Interestingly, as wave vector increases, the lowest
mode localizes onto the interface between the film and the substrate, while the
second mode evolves into a surface spin wave, localized on the outer layer. We
infer similar behavior for a Co film on Cu(100), though this evolution occurs
at rather larger wave vectors where, as we have shown previously, the modes are
heavily damped with the consequence that identification of distinct eigenmodes
is problematical.",0609236v1
2006-06-15,Soliton like wave packets in quantum wires,"At a Fano resonance in a quantum wire there is strong quantum mechanical
back-scattering. When identical wave packets are incident along all possible
modes of incidence, each wave packet is strongly scattered. The scattered wave
packets compensate each other in such a way that the outgoing wave packets are
similar to the incoming wave packets. This is as if the wave packets are not
scattered and not dispersed. This typically happens for the kink-antikink
solution of the Sine-Gordon model. As a result of such non-dispersive behavior,
the derivation of semi-classical formulas like the Friedel sum rule and the
Wigner delay time are exact at Fano resonance. For a single channel quantum
wire this is true for any potential that exhibit a Fano resonance. For a
multichannel quantum wire we give an easy prescription to check for a given
potential, if this is true. We also show that validity of the Friedel sum rule
may or may not be related to the conservation of charge. If there are
evanescent modes then even when charge is conserved, Friedel sum rule may break
down away from the Fano resonances.",0606412v2
2013-07-23,Trajectory eigenmodes of an orbiting wave source,"Resonances usually result from wave superpositions in cavities where they are
due to the wave spatio-temporal folding imposed by the boundaries. These energy
accumulations are the signature of the cavity eigenmodes. Here we study a
situation in which wave superposition results from the motion of a source
emitting sustained overlapping waves. It is found that resonances can be
produced in an unbounded space, the boundary conditions being now defined by
the trajectory. When periodic trajectories are investigated, it is found that
for a discrete subset of orbits, resonant wave modes are excited. Trajectory
eigenmodes thus emerge. These modes have three attributes. Their associated
resonant wave fields are the Fourier transform of the source's trajectory. They
are non-radiative and they satisfy the perimeter Bohr-Sommerfeld quantization
rule.",1307.5986v1
2017-09-23,Periodic traveling interfacial hydroelastic waves with or without mass II: Multiple bifurcations and ripples,"In a prior work, the authors proved a global bifurcation theorem for
spatially periodic interfacial hydroelastic traveling waves on infinite depth,
and computed such traveling waves. The formulation of the traveling wave
problem used both analytically and numerically allows for waves with
multi-valued height. The global bifurcation theorem required a one-dimensional
kernel in the linearization of the relevant mapping, but for some parameter
values, the kernel is instead two-dimensional. In the present work, we study
these cases with two-dimensional kernels, which occur in resonant and
non-resonant variants. We apply an implicit function theorem argument to prove
existence of traveling waves in both of these situations. We compute the waves
numerically as well, in both the resonant and non-resonant cases.",1709.08076v2
2021-03-12,Three-wave resonant interactions in the diatomic chain with cubic anharmonic potential: theory and simulations,"We consider a diatomic chain characterized by a cubic anharmonic potential.
After diagonalizing the harmonic case, we study in the new canonical variables,
the nonlinear interactions between the acoustical and optical branches of the
dispersion relation. Using the {\it wave turbulence} approach, we formally
derive two coupled wave kinetic equations, each describing the evolution of the
wave action spectral density associated to each branch. An $H$-theorem shows
that there exist an irreversible transfer of energy that leads to an
equilibrium solution characterized by the equipartition of energy in the new
variables. While in the monoatomic cubic chain, in the large box limit, the
main nonlinear transfer mechanism is based on four-wave resonant interactions,
the diatomic one is ruled by a three wave resonant process (two acoustical and
one optical wave): thermalization happens on shorter time scale for the
diatomic chain with respect to the standard chain. Resonances are possible only
if the ratio between the heavy and light masses is less than 3. Numerical
simulations of the deterministic equations support our theoretical findings.",2103.08336v1
2017-06-29,Reconfigurable topological spin wave beamsplitters and interferometers,"Conventional magnonic devices use three classes of magnetostatic waves that
require detailed manipulation of magnetization structure that makes the design
and the device/circuitry scalability difficult tasks. Here, we demonstrate that
devices based on topological exchange spin waves do not suffer from the problem
with additional nice features of nano-scale wavelength and high frequency. Two
results are reported. 1) A perpendicular ferromagnet on a honeycomb lattice is
generically a topological magnetic material in the sense that topologically
protected chiral edge spin waves exist in the band gap as long as spin-orbit
induced nearest-neighbor pseudodipolar interaction (and/or next-nearest
neighbor Dzyaloshinskii-Moriya interaction) is present. 2) As a proof of
concept, spin wave beamsplitters and spin wave interferometers are designed by
using domain walls to manipulate the propagation of topologically protected
chiral spin waves. Since magnetic domain walls can be controlled by magnetic
fields or electric current/fields, one can essentially draw, erase and redraw
different spin wave devices and circuitry on the same magnetic plate so that
the proposed devices are reconfigurable and tunable. Devices made from magnetic
topological materials are robust against both internal and external
perturbations such as the spin wave frequency variation and device geometry as
well as defects.",1706.09548v2
2019-10-29,Multi-Layer Restricted Boltzmann Machine Representation of 1D Quantum Many-Body Wave Functions,"We consider representing two classes of 1D quantum wave functions of spin
systems, including the AKLT and CFT correlator wave functions, in terms of
multi-layer restricted Boltzmann machines. In our prescription, the AKLT wave
function can be exactly represented by a 2-layer restricted Boltzmann machine
with five hidden spins per visible spin. The construction can be generalized to
prove that any MPS wave function on $N$ unit cells with finite bond dimension
can be approximated by a 2-layer restricted Boltzmann machine with
$\mathcal{O}(N)$ hidden spins within an error which scales linearly with $N$.
The Haldane-Shastry wave function or a chiral boson CFT correlator wave
function, as any Jastrow type of wave functions, can be exactly written as a
1-layer Boltzmann machine with $\mathcal{O}(N^2)$ hidden spins and $N$ visible
spins. Applying the cumulant expansion, we further find that the chiral boson
CFT correlator wave function (with small vertex operator conformal dimension
$\alpha$, i.e., $\alpha<0.1$) can be approximated, within 99.9\% accuracy up to
22 visible spins, by a 1-layer RBM with $\mathcal{O}(N)$ hidden spins. The
cumulant expansion also leads us to a physically inspiring result in which the
hidden spins of the restricted Boltzmann machine can be interpreted as the
conformal tower of the chiral boson CFT on the cylinder.",1910.13454v1
2021-06-21,Local non-linear excitation of sub-100 nm bulk-type spin waves by edge-localized spin waves in magnetic films,"The excitation of high-frequency short-wavelength spin waves is a challenge
limiting the application of these propagating magnetization disturbances in
information processing systems. We propose a method of local excitation of the
high-frequency spin waves using the non-linear nature of magnetization
dynamics. We demonstrate with numeric simulations that an edge-localized spin
wave can be used to excite plane waves propagating obliquely from the film's
edge at a doubled frequency and over twice shorter in wavelength. The
excitation mechanism is a direct result of the ellipticity of the magnetic
moments precession that is related to the edge-mode propagation. As a
consequence, the magnetization component tangential to the equilibrium
orientation oscillates with doubled temporal and spatial frequencies, which
leads to efficient excitation of the plane spin waves. Threshold-less
non-linear process of short-wavelength spin-wave excitation proposed in our
study is promising for integration with an inductive or point-like spin-torque
source of edge spin waves.",2106.11114v1
2006-01-05,Na content dependence of superconductivity and the spin correlations in Na_{x}CoO_{2}\cdot 1.3H_{2}O,"We report systematic measurements using the ^{59}Co nuclear quadrupole
resonance(NQR) technique on the cobalt oxide superconductors Na_{x}CoO_{2}\cdot
1.3H_{2}O over a wide Na content range x=0.25\sim 0.34. We find that T_c
increases with decreasing x but reaches to a plateau for x \leq0.28. In the
sample with x \sim 0.26, the spin-lattice relaxation rate 1/T_1 shows a T^3
variation below T_c and down to T\sim T_c/6, which unambiguously indicates the
presence of line nodes in the superconducting (SC) gap function. However, for
larger or smaller x, 1/T_1 deviates from the T^3 variation below T\sim 2 K even
though the T_c (\sim 4.7 K) is similar, which suggests an unusual evolution of
the SC state. In the normal state, the spin correlations at a finite wave
vector become stronger upon decreasing x, and the density of states at the
Fermi level increases with decreasing x, which can be understood in terms of a
single-orbital picture suggested on the basis of LDA calculation.",0601089v2
2009-11-20,Magnetisation dynamics in exchange coupled spring systems with perpendicular anisotropy,"Magnetisation dynamics in exchange spring magnets have been studied using
simulations of the FePt/Fe bilayer system. The FePt hard layer exhibits strong
perpendicular magnetocrystalline anisotropy, while the soft (Fe) layer has
negligible magnetocrystalline anisotropy. The variation of the local spin
orientation in the Fe layer is determined by the competition of the exchange
coupling interaction with the hard layer and the magnetostatic energy which
favours in-plane magnetisation. Dynamics were studied by monitoring the
response of the Fe layer magnetisation after the abrupt application of a
magnetic field which causes the systems to realign via precessional motion.
This precessional motion allows us to obtain the frequency spectrum and hence
examine the dynamical magnetisation motion. Since the rotation of the spins in
the soft layer does not have a well defined magnetic anisotropy, the system
does not present the usual frequency field characteristics for a thin film.
Additionally we obtain multi-peaked resonance spectra for the application of
magnetic fields perpendicular to the film plane, though we discount the
existence of spin wave modes and propose that this arises due to variations in
the local effective field across the Fe layer. The dynamic response is only
considered in the Fe layer, with the FePt layer held fixed in the perpendicular
orientation.",0911.4137v2
2010-11-30,Light-Meson Spectroscopy with COMPASS,"COMPASS is a multi-purpose fixed-target experiment at the CERN Super Proton
Synchrotron investigating the structure and spectrum of hadrons. One primary
goal is the search for new hadronic states, in particular spin-exotic mesons
and glueballs.
  After a short pilot run in 2004 with a 190 GeV/c $\pi^-$ beam on a Pb target,
which showed a significant spin-exotic $J^{PC} = 1^{-+}$ resonance consistent
with the controversial $\pi_1(1600)$, COMPASS collected large data samples with
negative and positive hadron beams on H$_2$, Ni, W, and Pb targets in 2008 and
2009.
  We present results from a partial-wave analysis of diffractive dissociation
of 190 GeV/c $\pi^-$ into $\pi^-\pi^+\pi^-$ final states on Pb and H$_2$
targets with squared four-momentum transfer in the range 0.1 < t' < 1
(GeV/c)^2. This reaction provides clean access to the light-quark meson
spectrum up to masses of 2.5 GeV/c^2. A first comparison of the data from Pb
and H$_2$ target shows a strong target dependence of the production strength of
states with spin projections $M = 0$ and 1 relative to the $a_2(1320)$.
  The 2004 Pb data were also analyzed in the region of small squared
four-momentum transfer t' < 10^{-2} (GeV/c)^2, where we observe interference of
diffractive production and photoproduction in the Coulomb-field of the Pb
nucleus.",1011.6615v2
2013-08-28,Quantum phase diagram of the $S=1/2$ triangular-lattice antiferromagnet Ba$_3$CoSb$_2$O$_9$,"The magnetic phases of the ideal spin-1/2 triangular-lattice antiferromagnet
Ba$_3$CoSb$_2$O$_9$ are identified and studied using $^{135,137}$Ba nuclear
magnetic resonance (NMR) spectroscopy in magnetic fields ranging to 30T,
oriented parallel and near perpendicular to the crystallographic $ab$-plane.
For both directions, the saturation field is approximately 33T. Notably, the
NMR spectra provide microscopic evidence for the stabilization of an up-up-down
spin configuration for in-plane fields, giving rise to an one-third
magnetization plateau ($M_\text{sat}/3$), as well as for a higher field phase
transition near to $\sim (3/5)M_\text{sat}$ for both field orientations. Phase
transitions are signaled by the evolution of the NMR spectra, and in some cases
through spin-lattice relaxation measurements. The results are compared with
expectations obtained from a semi-classical energy density modeling, in which
quantum effects are incorporated by effective interactions extracted from the
spin-wave analysis of the two-dimensional model. The interlayer coupling also
plays a significant role in the outcome. Good agreement between the model and
the experimental results is achieved, except for the case of fields approaching
the saturation value applied along the c-axis.",1308.6331v2
2015-10-20,Spin-polarized neutron matter: Critical unpairing and BCS-BEC precursor,"We obtain the critical magnetic field required for complete destruction of
$S$-wave pairing in neutron matter, thereby setting limits on the pairing and
superfluidity of neutrons in the crust and outer core of magnetars. We find
that for fields $B \ge 10^{17}$ G the neutron fluid is non-superfluid -- if
weaker spin-1 superfluidity does not intervene -- a result with profound
consequences for the thermal, rotational, and oscillatory behavior of
magnetars. Because the dineutron is not bound in vacuum, cold dilute neutron
matter cannot exhibit a proper BCS-BEC crossover. Nevertheless, owing to the
strongly resonant behavior of the $nn$ interaction at low densities, neutron
matter shows a precursor of the BEC state, as manifested in Cooper-pair
correlation lengths {being} comparable to the interparticle distance. We make a
systematic quantitative study of this type of BCS-BEC crossover in the presence
of neutron fluid spin-polarization induced by an ultra-strong magnetic field.
We evaluate the Cooper pair wave-function, quasiparticle occupation numbers,
and quasiparticle spectra for densities and temperatures spanning the BCS-BEC
crossover region. The phase diagram of spin-polarized neutron matter is
constructed and explored at different polarizations.",1510.06000v2
2016-01-27,Asymmetric angular dependence of spin-transfer torques in CoFe/Mg-B-O/CoFe magnetic tunnel junctions,"Using a first-principles noncollinear wave-function-matching method, we
studied the spin-transfer torques (STTs) in CoFe/Mg-B-O/CoFe(001) magnetic
tunnel junctions (MTJs), where three different types of B-doped MgO in the
spacer are considered, including B atoms replacing Mg atoms (Mg$_3$BO$_4$), B
atoms replacing O atoms (Mg$_4$BO$_3$), and B atoms occupying interstitial
positions (Mg$_4$BO$_4$) in MgO. A strong asymmetric angular dependence of STT
can be obtained both in ballistic CoFe/Mg$_3$BO$_4$ and CoFe/Mg$_4$BO$_4$ based
MTJs, whereas a nearly symmetric STT curve is observed in the junctions based
on CoFe/Mg$_4$BO$_3$. Furthermore, the asymmetry of the angular dependence of
STT can be suppressed significantly by the disorder of B distribution. Such
skewness of STTs in the CoFe/Mg-B-O/CoFe MTJs could be attributed to the
interfacial resonance states induced by the B diffusion into MgO spacer. The
present investigation demonstrates the feasibility of effectively enhancing
microwave output power in MgO based spin torque oscillator (STO) by doping the
B atoms into MgO spacer.",1601.07286v2
2018-07-13,Multiphoton Raman transitions and Rabi oscillations in driven spin systems,"In the framework of the non-secular perturbation theory based on the
Bogoliubov averaging method, the coherent dynamics of multiphoton Raman
transitions in a two-level spin system driven by an amplitude-modulated
microwave field is studied. Closed-form expressions for the Rabi frequencies of
these transitions have been obtained beyond the rotating wave approximation for
the low-frequency driving component. It is shown that spin states dressed by
the high-frequency component of the driving field are shifted due to the
Bloch-Siegert-like effect caused by antiresonant interactions with the strong
low-frequency driving. We predict that with increasing the order of the Raman
transition the Rabi frequency decreases and the contribution of the
Bloch-Siegert shift to this frequency becomes dominant. It is found that the
amplitude and phase of the Rabi oscillations strongly depend on the initial
phase of the low-frequency field as well as on detuning from multiphoton
resonance. The recent experimental data for the second- and third-order Raman
transitions observed for nitrogen-vacancy center in diamond [Z. Shu, et al.,
arXiv:1804. 10492] are well described in the frame of our approach. Our results
provide new possibilities for coherent control of quantum systems.",1807.05086v2
2021-08-12,Optically controllable magnetism in atomically thin semiconductors,"Electronic states in two-dimensional layered materials can exhibit a
remarkable variety of correlated phases including Wigner-crystals, Mott
insulators, charge density waves, and superconductivity. Recent experimental
and theoretical research has indicated that ferromagnetic phases can exist in
electronically-doped transition metal dichalcogenide (TMD) semiconductors, but
a stable magnetic state at zero magnetic field has eluded detection. Here, we
experimentally demonstrate that mesoscopic ferromagnetic order can be generated
and controlled by local optical pumping in monolayer WSe2 at zero applied
magnetic field. In a spatially resolved pump-probe experiment, we use
polarization-resolved reflectivity from excitonic states as a probe of
charge-carrier spin polarization. When the sample is electron-doped at density
$n_e = 10^{12} cm^{-2}$, we observe that a local, circularly-polarized,
microwatt-power optical pump breaks the symmetry between equivalent
ferromagnetic spin configurations and creates magnetic order which extends over
mesoscopic regions as large as 8 um x 5 um, bounded by sample edges and folds
in the 2D semiconductor. The experimental signature of magnetic order is
circular dichroism (CD) in reflectivity from the excitonic states, with
magnitude exceeding 20% at resonant wavelengths. The helicity of the pump
determines the orientation of the magnetic state, which can be aligned along
the two principle out-of-plane axes. In contrast to previous studies in 2D
materials that have required non-local, slowly varying magnetic fields to
manipulate magnetic phases, the demonstrated capability to control long-range
magnetism and corresponding strong CD with local and tunable optical pumps is
highly versatile. This discovery will unlock new TMD-based spin and optical
technologies and enable sophisticated control of correlated electron phases in
two-dimensional electron gases (2DEGs).",2108.05931v1
2019-07-26,Ground state phase diagram of the doped Hubbard model on the 4-leg cylinder,"We study the ground state properties of the Hubbard model on a 4-leg cylinder
with doped hole concentration per site $\delta\leq 12.5\%$ using density-matrix
renormalization group. By keeping a large number of states for long system
sizes, we find that the nature of the ground state is remarkably sensitive to
the presence of next-nearest-neighbor hopping $t'$. Without $t'$ the ground
state of the system corresponds with the insulating filled stripe phase with
long-range charge-density-wave (CDW) order and short-range incommensurate spin
correlations appears. However, for a small negative $t'$ a phase characterized
by coexisting algebraic d-wave superconducting (SC)- and algebraic CDW
correlations. In addition, it shows short range spin- and fermion correlations
consistent with a canonical Luther-Emery (LE) liquid, except that the charge-
and spin periodicities are consistent with half-filled stripes instead of the
$4 k_F$ and $2 k_F$ wavevectors generic for one dimensional chains. For a small
positive $t'$ yet another phase takes over showing similar SC and CDW
correlations. However, the fermions are now characterized by a (near) infinite
correlation length while the gapped spin system is characterized by simple
staggered antiferromagnetic correlations. We will show that this is consistent
with a LE formed from a weakly coupled (BCS like) d-wave superconductor on the
ladder where the interactions have only the effect to stabilize a cuprate style
magnetic resonance.",1907.11728v1
2020-12-11,Universal collective modes from strong electronic correlations: Modified $1/\mathcal{N}_f$ theory with application to high-$T_c$ cuprates,"A nonzero-temperature technique for strongly correlated electron lattice
systems, combining elements of both variational wave function (VWF) approach
and expansion in the inverse number of fermionic flavors ($1/\mathcal{N}_f$),
is developed. The departure point, VWF method, goes beyond the renormalized
mean-field theory and provides semi-quantitative description of principal
equilibrium properties of high-$T_c$ superconducting cuprates. The developed
here scheme of VWF+$1/\mathcal{N}_f$, in the leading order provides dynamical
spin and charge responses around the VWF solution, generalizing the
weak-coupling spin-fluctuation theory to the regime of strong correlations.
Thermodynamic corrections to the correlated saddle-point state arise
systematically at consecutive orders. Explicitly, VWF+$1/\mathcal{N}_f$ is
applied to evaluate dynamical response functions for the hole-doped Hubbard
model and compared with available determinant quantum-Monte-Carlo data,
yielding a good overall agreement in the regime of coherent collective-mode
dynamics. The emergence of well-defined spin and charge excitations from the
incoherent continua is explicitly demonstrated and a non-monotonic dependence
of the charge-excitation energy on the interaction magnitude is found. The
charge-mode energy saturates slowly when approaching the strong-coupling limit,
which calls for a reevaluation of the $t$-$J$-model approach to the charge
dynamics in favor of more general $t$-$J$-$U$ and $t$-$J$-$U$-$V$ models. The
results are also related to recent inelastic resonant $X$-ray and neutron
scattering experiments for the high-$T_c$ cuprates.",2012.06630v2
2022-04-09,Bifurcation analysis of strongly nonlinear injection locked spin torque oscillators,"We investigate the dynamics of an injection locked in-plane uniform spin
torque oscillator for several forcing configurations at large driving
amplitudes. For the analysis, the spin wave amplitude equation is used to
reduce the dynamics to a general oscillator equation in which the forcing is a
complex valued function $F(p,{\psi})\propto{\epsilon}_1
(p)cos({\psi})+i{\epsilon}_2 (p)sin({\psi})$. Assuming that the oscillator is
strongly nonisochronous and/or forced by a power forcing
$(|{\nu}{\epsilon}_1/{\epsilon}_2 |\gg 1)$, we show that the parameters
${\epsilon}_{1,2} (p)$ govern the main bifurcation features of the Arnold
tongue diagram : (i) the locking range asymmetry is mainly controlled by
$d{\epsilon}_1 (p)/dp$, (ii) the Taken-Bogdanov bifurcation occurs for a power
threshold depending on ${\epsilon}_{1,2} (p)$ and (iii) the frequency
hysteretic range is related to the transient regime through the resonant
frequency at zero mismatch frequency. Then, the model is compared with the
macrospin simulation for driving amplitudes as large as $10^0-10^3 A/m$ for the
magnetic field and $10^{10}-10^{12} A/m^2$ for the current density. As
predicted by the model, the forcing configuration (nature of the driving
signal, applied direction, the harmonic orders) affects substantially the
oscillator dynamic. However, some discrepancies are observed. In particular,
the prediction of the frequency and power locking range boundaries may be
misestimated if the hysteretic boundaries are of same magnitude order.
Moreover, the misestimation can be of two different types according if the
bifurcation is Saddle node or Taken Bogdanov. These effects are a further
manifestation of the complexity of the dynamics in nonisochronous
auto-oscillators.",2204.04454v1
2022-06-22,Resonant Islands of Effective-One-Body Dynamics,"We study the chaotic signatures of the geodesic dynamics of a non-spinning
test particle in the effective-one-body (EOB) formalism for the inspiral
process of spinning binary black holes. We first show that the second order
post-Newtonian (2PN) EOB dynamics is non-integrable by demonstrating that the
EOB metric does not satisfy the criterion for the existence of Carter constant.
We then employ the numerical study to find the plateaus of the rotation curve,
which are associated with the existence of Birkhoff islands in the Poincar\'e
surface of section, signifying the chaotic dynamics in the system. Our results
show the signatures of chaos for the EOB dynamics, especially in the regime of
interest for which the Kerr bounds of the component black holes hold. We also
find that chaotic behavior is more obvious as the spin parameter $a$ of the
deformed EOB background metric increases. Our results can help to uncover the
implications of dynamical chaos in gravitational wave astronomy. Finally, we
also present some preliminary results due to corrections at 3PN order.",2206.10966v2
2024-03-05,Microelectronic readout of a diamond quantum sensor,"Quantum sensors based on the nitrogen-vacancy (NV) centre in diamond are
rapidly advancing from scientific exploration towards the first generation of
commercial applications. While significant progress has been made in developing
suitable methods for the manipulation of the NV centre spin state, the
detection of the defect luminescence has so far limited the performance of
miniaturized sensor architectures. The recent development of photoelectric
detection of the NV centre's spin state offers a path to circumvent these
limitations, but has to-date required research-grade low current amplifiers to
detect the picoampere-scale currents obtained from these systems. Here we
report on the photoelectric detection of magnetic resonance (PDMR) with NV
ensembles using a complementary metal-oxide semiconductor (CMOS) device. The
integrated circuit delivers a digitized output of the diamond sensor with low
noise and 50 femtoampere resolution. This integration provides the last missing
component on the path to a compact, diamond-based quantum sensor. The device is
suited for continuous wave (CW) as well as pulsed operation. We demonstrate its
functionality with DC and AC magnetometry up to several megahertz, coherent
spin rotation and multi-axial decoupling sequences for quantum sensing.",2403.03090v2
2000-02-11,Coexistent State of Charge Density Wave and Spin Density Wave in One-Dimensional Quarter Filled Band Systems under Magnetic Fields,"We theoretically study how the coexistent state of the charge density wave
and the spin density wave in the one-dimensional quarter filled band is
enhanced by magnetic fields. We found that when the correlation between
electrons is strong the spin density wave state is suppressed under high
magnetic fields, whereas the charge density wave state still remains. This will
be observed in experiments such as the X-ray measurement.",0002165v3
2016-08-26,Strain-induced spin resonance shifts in silicon devices,"In spin-based quantum information processing devices, the presence of control
and detection circuitry can change the local environment of a spin by
introducing strain and electric fields, altering its resonant frequencies.
These resonance shifts can be large compared to intrinsic spin line-widths and
it is therefore important to study, understand and model such effects in order
to better predict device performance. Here we investigate a sample of bismuth
donor spins implanted in a silicon chip, on top of which a superconducting
aluminium micro-resonator has been fabricated. The on-chip resonator provides
two functions: first, it produces local strain in the silicon due to the larger
thermal contraction of the aluminium, and second, it enables sensitive electron
spin resonance spectroscopy of donors close to the surface that experience this
strain. Through finite-element strain simulations we are able to reconstruct
key features of our experiments, including the electron spin resonance spectra.
Our results are consistent with a recently discovered mechanism for producing
shifts of the hyperfine interaction for donors in silicon, which is linear with
the hydrostatic component of an applied strain.",1608.07346v3
2020-04-30,Tilting Uranus: Collisions versus Spin--Orbit Resonance,"In this paper, we investigate whether Uranus's 98$^{\circ}$ obliquity was a
by-product of a secular spin-orbit resonance assuming that the planet
originated closer to the Sun. In this position, Uranus's spin precession
frequency is fast enough to resonate with another planet located beyond Saturn.
Using numerical integration, we show that resonance capture is possible in a
variety of past solar system configurations, but that the timescale required to
tilt the planet to 90$^{\circ}$ is of the order $\sim\!10^{8}$ yr -- a timespan
that is uncomfortably long. A resonance kick could tilt the planet to a
significant 40$^{\circ}$ in $\sim\!10^{7}$ yr only if conditions were ideal. We
also revisit the collisional hypothesis for the origin of Uranus's large
obliquity. We consider multiple impacts with a new collisional code that builds
up a planet by summing the angular momentum imparted from impactors. Because
gas accretion imparts an unknown but likely large part of the planet's spin
angular momentum, we compare different collisional models for tilted, untilted,
spinning, and nonspinning planets. We find that a 1 $M_{\oplus}$ strike is
sufficient to explain the planet's current spin state, but that two
$0.5\,M_{\oplus}$ collisions produce better likelihoods. Finally, we
investigate hybrid models and show that resonances must produce a tilt of at
least $\sim\!40^{\circ}$ for any noticeable improvements to the collision
model. Because it is difficult for spin-orbit resonances to drive Uranus's
obliquity to 98$^{\circ}$ even under these ideal conditions, giant impacts seem
inescapable.",2004.14913v3
2021-04-22,"Spin-orbit resonances of high-eccentricity asteroids: regular, switching, and jumping","Few solar system asteroids and comets are found in high eccentricity orbits
($e > 0.9$) but in the primordial planetesimal disks and in exoplanet systems
around dying stars such objects are believed to be common. For 2006 HY51, the
main belt asteroid with the highest known eccentricity 0.9684, we investigate
the probable rotational states today using our computer-efficient chaotic
process simulation method. Starting with random initial conditions, we find
that this asteroid is inevitably captured into stable spin-orbit resonances
typically within tens to a hundred Myr. The resonances are confirmed by direct
integration of the equation of motion in the vicinity of end-points. Most
resonances are located at high spin values above 960 times the mean motion
(such as 964:1 or 4169:4), corresponding to rotation periods of a few days. We
discover three types of resonance in the high-eccentricity regime: 1) regular
circulation with weakly librating aphelion velocities and integer-number
spin-orbit commensurabilities; 2) switching resonances of higher order with
orientation alternating between aligned (0 or $\pi$) and sidewise ($\pi/2$)
angles at aphelia and perihelia; 3) jumping resonances with aphelion spin
alternating between two quantum states in the absence of spin-orbit
commensurability. The islands of equilibrium are numerous at high spin rates
but small in parameter space area, so that it takes millions of orbits of
chaotic wandering to accidentally entrap in one of them. We discuss the
implications of this discovery for the origins and destiny of high-eccentricity
objects and the prospects of extending this analysis to the full 3D treatment.",2104.11338v1
2023-08-31,Resonance contributions to nucleon spin structure in Holographic QCD,"We study polarized inelastic electron-nucleon scattering at low momentum
transfer in the Witten-Sakai-Sugimoto model of holographic QCD, focusing on
resonance production contributions to the nucleon spin structure functions. Our
analysis includes both spin $3/2$ and spin $1/2$ low-lying nucleon resonances
with positive and negative parity. We determine, in turn, the helicity
amplitudes for nucleon-resonance transitions and the resonance contributions to
the neutron and proton generalized spin polarizabilities. Extrapolating the
model parameters to realistic QCD data, our analysis, triggered by recent
experimental results from Jefferson Lab, agrees with the observation that the
$\Delta(1232)$ resonance gives the dominant contribution to the forward spin
polarizabilities at low momentum transfer. The contribution is negative and
tends to zero as the momentum transfer increases. As expected, the contribution
of the $\Delta(1232)$ to the longitudinal-transverse polarizabilities is
instead negligible. The latter, for both nucleons, turn out the be negative
functions with zero asymptote. The holographic results, at least for the proton
where enough data are available, are in qualitative agreement with the
resonance contributions to the spin polarizabilities extracted from
experimental data on the helicity amplitudes.",2308.16833v2
2021-08-11,Charge density waves in multiple-$Q$ spin states,"Coupling between spin and charge degrees of freedom in electrons is a source
of various electronic and magnetic properties of solids. We theoretically study
charge density waves induced by the spin-charge coupling in the presence of
magnetic orderings in itinerant magnets. By performing a perturbative
calculation in the weak-coupling limit of the Kondo lattice model, we derive a
useful formula for the relationship between charge and spin density waves,
which can be applied to any magnetic orderings, including noncollinear and
noncoplanar ones composed of multiple spin density waves called multiple-$Q$
magnetic orderings. We demonstrate the predictive power for single-$Q$ and
double-$Q$ states including skyrmion and meron-antimeron crystals on a square
lattice, in comparison with the numerical calculations. Moreover, we show that
the charge density waves contain richer information than the spin density
waves, and are indeed useful in distinguishing the spin textures with similar
spin structure factors. We discuss the relation to bond modulation in terms of
the kinetic bond energy and the vector spin chirality. We also perform
numerical calculations beyond the perturbative regime and find that the charge
density waves can be enhanced when the electron filling is commensurate.
Furthermore, we investigate the effect of the spin-orbit coupling, which can
lead to additional charge density waves owing to effective anisotropic magnetic
interactions in momentum space. Our result will provide a way to identify
complex magnetic orderings and their origins from the charge modulations.",2108.04997v2
2015-09-16,Fano resonance in a normal metal/ferromagnet-quantum dot-superconductor device,"We investigate theoretically the Andreev transport through a quantum dot
strongly coupled with a normal metal/ferromagnet and a superconductor
(N/F-QD-S), in which the interplay between the Kondo resonance and the Andreev
bound states (ABSs) has not been clearly clarified yet. Here we show that the
interference between the Kondo resonance and the ABSs modifies seriously the
lineshape of the Kondo resonance, which manifests as a Fano resonance. The
ferromagnetic lead with spin-polarization induces an effective field, which
leads to splitting both of the Kondo resonance and the ABSs. The
spin-polarization together with the magnetic field applied provides an
alternative way to tune the lineshape of the Kondo resonances, which is
dependent of the relative positions of the Kondo resonance and of the ABSs.
These results indicate that the interplay between the Kondo resonance and the
ABSs can significantly affect the Andreev transport, which could be tested by
experiments.",1509.04801v1
2002-02-25,Eccentricity Evolution for Planets in Gaseous Disks,"We investigate the hypothesis that interactions between a giant planet and
the disk from which it forms promote eccentricity growth. These interactions
are concentrated at discrete Lindblad and corotation resonances. Interactions
at principal Lindblad resonances cause the planet's orbit to migrate and open a
gap in the disk if the planet is sufficiently massive. Those at first order
Lindblad and corotation resonances change the planet's orbital eccentricity.
Eccentricity is excited by interactions at external Lindblad resonances which
are located on the opposite side of corotation from the planet, and damped by
co-orbital Lindblad resonances which overlap the planet's orbit. If the planet
clears a gap in the disk, the rate of eccentricity damping by co-orbital
Lindblad resonances is reduced. Density gradients associated with the gap
activate eccentricity damping by corotation resonances at a rate which
initially marginally exceeds that of eccentricity excitation by external
Lindblad resonances. But the corotation torque drives a mass flux which reduces
the density gradient near the resonance. Sufficient partial saturation of
corotation resonances can tip the balance in favor of eccentricity excitation.
A minimal initial eccentricity of a few percent is required to overcome viscous
diffusion which acts to unsaturate corotation resonances by reestablishing the
large scale density gradient. Thus eccentricity growth is a finite amplitude
instability. Formally, interactions at the apsidal resonance, which is a
special kind of co-orbital Lindblad resonance, appears to damp eccentricity
faster than external Lindblad resonances can excite it. However, apsidal waves
have such long wavelengths that they do not propagate in protoplanetary disks.
This reduces eccentricity damping by the apsidal resonance to a modest level.",0202462v1
2020-12-16,Non-Invasive Near-field Spectroscopy of Single Sub-Wavelength Complementary Resonators,"Subwavelength metallic resonators provide a route to achieving strong
light-matter coupling by means of tight confinement of resonant electromagnetic
fields. Investigation of such resonators however often presents experimental
difficulties, particularly at terahertz (THz) frequencies. A single
subwavelength resonator weakly interacts with THz beams, making it difficult to
probe it using far-field methods; whereas arrays of resonators exhibit
inter-resonator coupling, which affects the resonator spectral signature and
field confinement. Here, traditional far-field THz spectroscopy is
systematically compared with aperture-type THz near-field microscopy for
investigating complementary THz resonators. Whilst the far-field method proves
impractical for measuring single resonators, the near-field technique gives
high signal-to-noise spectral information, only achievable in the far-field
with resonator arrays. At the same time, the near-field technique allows us to
analyze single resonators - free from inter-resonator coupling present in
arrays - without significant interaction with the near-filed probe.
Furthermore, the near-field technique allows highly confined fields and surface
waves to be mapped in space and time. This information gives invaluable insight
into resonator spectral response in arrays. This near-field microscopy and
spectroscopy method enables investigations of strong light-matter coupling at
THz frequencies in the single-resonator regime.",2012.09137v1
1999-08-29,Local spin resonance and spin-Peierls-like phase transition in a geometrically frustrated antiferromagnet,"Using inelastic magnetic neutron scattering we have discovered a localized
spin resonance at 4.5 meV in the ordered phase of the geometrically frustrated
cubic antiferromagnet $\rm ZnCr_2O_4$. The resonance develops abruptly from
quantum critical fluctuations upon cooling through a first order transition to
a co-planar antiferromagnet at $T_c=12.5(5)$ K. We argue that this transition
is a three dimensional analogue of the spin-Peierls transition.",9908433v2
2002-08-22,A scheme for electrical detection of spin resonance signal from a single electron trap,"We study a scheme for electrical detection of the spin resonance (ESR) of a
single electron trapped near a Field Effect Transistor (FET) conduction
channel. In this scheme, the resonant Rabi oscillations of the trapped electron
spin cause a modification of the average occupancy of a shallow trap, which can
be detected through the change in the FET channel resistivity. We show that the
dependence of the channel resistivity on the frequency of the rf field can have
either peak or dip at the Larmor frequency of the electron spin in the trap.",0208438v1
2003-05-07,Voltage-Controlled Spin Selection in a Magnetic Resonant Tunnelling Diode,"We have fabricated all II-VI semiconductor resonant tunneling diodes based on
the (Zn,Mn,Be)Se material system, containing dilute magnetic material in the
quantum well, and studied their current-voltage characteristics. When subjected
to an external magnetic field the resulting spin splitting of the levels in the
quantum well leads to a splitting of the transmission resonance into two
separate peaks. This is interpreted as evidence of tunneling transport through
spin polarized levels, and could be the first step towards a voltage controlled
spin filter.",0305124v1
2012-11-01,A one-dimensional spin-orbit interferometer,"We demonstrate that the combination of an external magnetic field and the
intrinsic spin-orbit interaction results in nonadiabatic precession of the
electron spin after transmission through a quantum point contact (QPC). We
suggest that this precession may be observed in a device consisting of two QPCs
placed in series. The pattern of resonant peaks in the transmission is strongly
influenced by the non-abelian phase resulting from this precession. Moreover, a
novel type of resonance which is associated with suppressed, rather than
enhanced, transmission emerges in the strongly nonadiabatic regime. The shift
in the resonant transmission peaks is dependent on the spin-orbit interaction
and therefore offers a novel way to directly measure these interactions in a
ballistic 1D system.",1211.0080v1
2013-06-03,Nanoscopic interferometer model for spin resonance in current noise,"We study a model for the observed phenomenon of electron spin resonance (ESR)
at the Zeeman frequency as seen by a scanning tunneling microscope (STM) via
its current noise. The model for this ESR-STM phenomenon allows the STM current
to flow in two arms of a nanoscopic interferometer, one arm has direct
tunneling from the tip to the substrate while the second arm has tunneling
through two spin states. We evaluate analytically the noise spectrum for
non-polarized leads, as relevant to the experimental setup. We show that
spin-orbit interactions allow for an interference of two tunneling paths
resulting in a resonance effect.",1306.0363v1
2013-07-24,Quantum-Information Processing with Hybrid Spin-Photon Qubit Encoding,"We introduce a scheme to perform quantum-information processing that is based
on a hybrid spin-photon qubit encoding. The proposed qubits consist of
spin-ensembles coherently coupled to microwave photons in coplanar waveguide
resonators. The quantum gates are performed solely by shifting the resonance
frequencies of the resonators on a ns timescale. An additional cavity
containing a Cooper-pair box is exploited as an auxiliary degree of freedom to
implement two-qubit gates. The generality of the scheme allows its potential
implementation with a wide class of spin systems.",1307.6474v1
2013-07-28,Real Time Electrical Detection of Coherent Spin Oscillations,"We demonstrate that the bandwidth of pulsed electrically detected magnetic
resonance can be increased to at least 80 MHz using a radio
frequency-reflectometry detection scheme. Using this technique, we measure
coherent spin oscillations in real time during a resonant microwave pulse. We
find that the observed signal is in quantitative agreement with simulations
based on rate equations modeling the recombination dynamics of the spin system
under study. The increased bandwidth opens the way to electrically study faster
spin-dependent recombination processes, e.g., in direct semiconductors which so
far have almost exclusively been studied by optically detected magnetic
resonance.",1307.7413v1
2015-10-22,Anomalous longitudinal relaxation of nuclear spins in CaF$_2$,"We consider the effect of non-secular resonances for interacting nuclear
spins in solids which were predicted theoretically to exist in the presence of
strong static and strong radio-frequency magnetic fields. These resonances
imply corrections to the standard secular approximation for the nuclear
spin-spin interaction in solids, which, in turn, should lead to an anomalous
longitudinal relaxation in nuclear magnetic resonance experiments. In this
article, we investigate the feasibility of the experimental observation of this
anomalous longitudinal relaxation in calcium fluoride (CaF$_2$) and conclude
that such an observation is realistic.",1510.06589v1
2018-05-07,Resonant Spin Exchange between Heteronuclear Atoms Assisted by Periodic Driving,"We propose a general scheme for inducing resonant exchange between spins or
pseudo-spins of unmatched levels via periodic driving. The basic idea is
illustrated for a system of two heteronuclear atoms, for which analytical
results are provided for the effective spin exchange (SE) interaction strength.
It is then applied to the mixture of 23Na and 87Rb atoms with a radio-frequency
(rf) or microwave field near-resonant to the mismatched Zeeman level spacings.
SE interaction engineered this way is applicable to ultracold quantum gas
mixtures involving spinor Bose-Bose, Bose-Fermi, and Fermi-Fermi atoms.",1805.02310v1
2018-09-07,Nuclear spin pumping by pulling effect,"The nuclear-to-electron spin angular momentum conversion via hyperfine
coupling in a normal metal (NM)/ferromagnet (FM) bilayer system is
theoretically investigated by using the nonequilibrium Green's function method.
The spin current generated by the nuclear magnetic resonance (NMR) is found to
be enhanced by the pulling effect in the FM when the temperature is lower than
NMR resonance frequency. In a Co/Pt bilayer system, we show that the spin
current by NMR becomes larger than that of the ferromagnetic resonance (FMR).",1809.02272v1
2019-07-17,Role of interactions in the energy of the spin resonance peak in Fe-based superconductors,"We consider the spin response within the five-orbital model for iron-based
superconductors and study two cases: equal and unequal gaps in different bands.
In the first case, the spin resonance peak in the superconducting state appears
below the characteristic energy scale determined by the gap magnitude,
$2\Delta_L$. In the second case, the energy scale corresponds to the sum of
smaller and larger gap magnitudes, $\Delta_L + \Delta_S$. Increasing the values
of the Hubbard interaction and the Hund's exchange, we observe a shift of the
spin resonance energy to lower frequencies.",1907.08133v1
2020-10-27,Mitigation of Space-Charge-Driven Resonance and Instability in High-Intensity Linear Accelerators via Beam Spinning,"For modern high-intensity linear accelerators, the well-known envelope
instability and recently reported fourth-order particle resonance impose a
fundamental operational limit (i.e., zero-current phase advance should be less
than 90 deg). Motivated by the stability of spinning flying objects, we propose
a novel approach of using spinning beams to surpass this limit. We discovered
that spinning beams have an intrinsic characteristic that can suppress the
impact of the fourth-order resonance on emittance growth and the associated
envelope instability.",2010.14080v3
2023-11-17,Enhancing Electron-Nuclear Resonances by Dynamical Control Switching,"We present a general method to realize resonant coupling between spins even
though their energies are of different scales. Applying the method to the
electron and nuclear spin systems such as a nitrogen-vacancy (NV) center with
its nearby nuclei, we show that a specific dynamical switching of the electron
spin Rabi frequency achieves efficient electron-nuclear coupling, providing a
much stronger quantum sensing signal and dynamic nuclear polarization than
previous methods. This protocol has applications in high-field nanoscale
nuclear magnetic resonances as well as low-power quantum control of nuclear
spins.",2311.10650v1
2007-03-17,Large-amplitude coherent spin waves exited by spin-polarized current in nanoscale spin valves,"We present spectral measurements of spin-wave excitations driven by direct
spinpolarized current in the free layer of nanoscale
Ir20Mn80/Ni80Fe20/Cu/Ni80Fe20 spin valves. The measurements reveal that
large-amplitude coherent spin wave modes are excited over a wide range of bias
current. The frequency of these excitations exhibits a series of jumps as a
function of current due to transitions between different localized nonlinear
spin wave modes of the Ni80Fe20 nanomagnet. We find that micromagnetic
simulations employing the Landau-Lifshitz-Gilbert equation of motion augmented
by the Slonczewski spin torque term (LLGS) accurately describe the frequency of
the current-driven excitations including the mode transition behavior. However
LLGS simulations give qualitatively incorrect predictions for the amplitude of
excited spin waves as a function of current.",0703458v2
2011-04-04,Electric Control of Spin Currents and Spin-Wave Logic,"Spin waves in insulating magnets are ideal carriers for spin currents with
low energy dissipation. An electric field can modify the dispersion of spin
waves, by directly affecting, via spin-orbit coupling, the electrons that
mediate the interaction between magnetic ions. Our microscopic calculations
based on the super-exchange model indicate that this effect of the electric
field is sufficiently large to be used to effectively control spin currents. We
apply these findings to the design of a spin-wave interferometric device, which
acts as a logic inverter and can be used as a building block for
room-temperature, low-dissipation logic circuits.",1104.0657v2
2020-12-23,Topological spin-plasma waves,"The surface of a topological insulator hosts Dirac electronic states with the
spin-momentum locking, which constrains spin orientation perpendicular to
electron momentum. As a result, collective plasma excitations in the
interacting Dirac liquid manifest themselves as coupled charge- and spin-waves.
Here we demonstrate that the presence of the spin component enables effective
coupling between plasma waves and spin waves at interfaces between the surface
of a topological insulator and insulating magnet. Moreover, the helical nature
of spin-momentum locking textures provides the phase winding in the coupling
between the spin and plasma waves that makes the spectrum of hybridized
spin-plasma modes to be topologically nontrivial. We also show that such
topological modes lead to a large thermal Hall response.",2012.12632v2
2015-12-11,Recent Results on Spectroscopy from COMPASS,"The COmmon Muon and Proton Apparatus for Structure and Spectroscopy (COMPASS)
is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron
(SPS) aimed at studying the structure and spectrum of hadrons. The two-stage
spectrometer has a good acceptance for charged as well as neutral particles
over a wide kinematic range and is thus able to measure a wide range of
reactions. Light mesons are studied with negative (mostly $\pi^-$) and positive
($p$, $\pi^+$) hadron beams with a momentum of 190 GeV/$c$. The light-meson
spectrum is investigated in various final states produced in diffractive
dissociation reactions at squared four-momentum transfers to the target between
0.1 and 1.0 (GeV/$c$)$^2$. The flagship channel is the $\pi^-\pi^+\pi^-$ final
state, for which COMPASS has recorded the currently largest data sample. These
data not only allow for measuring the properties of known resonances with high
precision, but also for searching for new states. Among these is a new
resonance-like signal, the $a_1(1420)$, with unusual properties. The findings
are confirmed by the analysis of the $\pi^-\pi^0\pi^0$ final state. Possible
bias introduced by the parametrizations used to describe the $\pi\pi$ $S$-wave
is studied using a novel analysis technique, which extracts the amplitude of
the $\pi^+\pi^-$ sub-system as a function of $3\pi$ mass from the data. Of
particular interest is the resonance content of the partial wave with
spin-exotic $J^{PC} = 1^{-+}$ quantum numbers, which are forbidden for
quark-antiquark states. This wave is studied in the two $3\pi$ channels.
Further insight is gained by studying diffractively produced $\pi^-\eta$ or
$\pi^-\eta'$ final states.",1512.03599v1
2018-03-15,Mechanically Controlled Quantum Interference in Graphene Break Junctions,"The ability to detect and distinguish quantum interference signatures is
important for both fundamental research and for the realization of devices
including electron resonators, interferometers and interference-based spin
filters. Consistent with the principles of subwavelength optics, the wave
nature of electrons can give rise to various types of interference effects,
such as Fabry-P\'erot resonances, Fano resonances and the Aharonov-Bohm effect.
Quantum-interference conductance oscillations have indeed been predicted for
multiwall carbon nanotube shuttles and telescopes, and arise from atomic-scale
displacements between the inner and outer tubes. Previous theoretical work on
graphene bilayers indicates that these systems may display similar interference
features as a function of the relative position of the two sheets. Experimental
verification is, however, still lacking. Graphene nanoconstrictions represent
an ideal model system to study quantum transport phenomena due to the
electronic coherence and the transverse confinement of the carriers. Here, we
demonstrate the fabrication of bowtie-shaped nanoconstrictions with
mechanically controlled break junctions (MCBJs) made from a single layer of
graphene. We find that their electrical conductance displays pronounced
oscillations at room temperature, with amplitudes that modulate over an order
of magnitude as a function of sub-nanometer displacements. Surprisingly, the
oscillations exhibit a period larger than the graphene lattice constant.
Charge-transport calculations show that the periodicity originates from a
combination of quantum-interference and lattice-commensuration effects of two
graphene layers that slide across each other. Our results provide direct
experimental observation of Fabry-P\'erot-like interference of electron waves
that are partially reflected/transmitted at the edges of the graphene bilayer
overlap region.",1803.05642v2
2006-10-26,Electron spin as a spectrometer of nuclear spin noise and other fluctuations,"This chapter describes the relationship between low frequency noise and
coherence decay of localized spins in semiconductors. Section 2 establishes a
direct relationship between an arbitrary noise spectral function and spin
coherence as measured by a number of pulse spin resonance sequences. Section 3
describes the electron-nuclear spin Hamiltonian, including isotropic and
anisotropic hyperfine interactions, inter-nuclear dipolar interactions, and the
effective Hamiltonian for nuclear-nuclear coupling mediated by the electron
spin hyperfine interaction. Section 4 describes a microscopic calculation of
the nuclear spin noise spectrum arising due to nuclear spin dipolar flip-flops
with quasiparticle broadening included. Section 5 compares our explicit
numerical results to electron spin echo decay experiments for phosphorus doped
silicon in natural and nuclear spin enriched samples.",0610716v2
2014-10-07,Y3Fe5O12 Spin Pumping for Quantitative Understanding of Pure Spin Transport and Spin Hall Effect in a Broad Range of Materials,"Using Y3Fe5O12 (YIG) thin films grown by our sputtering technique, we study
dynamic spin transport in nonmagnetic (NM), ferromagnetic (FM) and
antiferromagnetic (AF) materials by ferromagnetic resonance (FMR) spin pumping.
From both inverse spin Hall effect (ISHE) and damping enhancement, we determine
the spin mixing conductance and spin Hall angle in many metals. Surprisingly,
we observe robust spin conduction in AF insulators excited by an adjacent YIG
at resonance. This demonstrates that YIG spin pumping is a powerful and
versatile tool for understanding spin Hall physics, spin-orbit coupling (SOC),
and magnetization dynamics in a broad range of materials.",1410.1597v1
2018-07-25,Nuclear spin dynamics influenced and detected by electron spin polarization in CdTe/CdMgTe quantum wells,"Nuclear spin coherence and relaxation dynamics of all constituent isotopes of
an n-doped CdTe/(Cd,Mg)Te quantum well structure are studied employing
optically detected nuclear magnetic resonance. Using time-resolved pump-probe
Faraday ellipticity, we generate and detect the coherent spin dynamics of the
resident electrons. The photogenerated electron spin polarization is
transferred into the nuclear spin system, which becomes polarized and acts back
on the electron spins as the Overhauser field. Under the influence of resonant
radio frequency pulses, we trace the coherent spin dynamics of the nuclear
isotopes $^{111}$Cd, $^{113}$Cd, and $^{125}$Te. We measure nuclear Rabi
oscillations, the inhomogeneous dephasing time $T_2^*$, the spin coherence time
$T_2$, and the longitudinal relaxation time $T_1$. Furthermore, we investigate
the influence of the laser excitation and the corresponding electron spin
polarization on the nuclear spin relaxation time and find a weak extension of
this time induced by interaction with the electron spins.",1807.09672v2
2021-08-05,Polarizing electron spins with a superconducting flux qubit,"Electron spin resonance (ESR) is a useful tool to investigate properties of
materials in magnetic fields where high spin polarization of target electron
spins is required in order to obtain high sensitivity. However, the smaller
magnetic fields becomes, the more difficult high polarization is passively
obtained by thermalization. Here, we propose to employ a superconducting flux
qubit (FQ) to polarize electron spins actively. We have to overcome a large
energy difference between the FQ and electron spins for efficient energy
transfer among them. For this purpose, we adopt a spin-lock technique on the FQ
where the Rabi frequency associated with the spin-locking can match the
resonance (Larmor) one of the electron spins. We find that adding dephasing on
the spins is beneficial to obtain high polarization of them, because otherwise
the electron spins are trapped in dark states that cannot be coupled with the
FQ. We show that our scheme can achieve high polarization of electron spins in
realistic experimental conditions.",2108.02463v1
2023-04-26,Critical Cavity-Magnon Polariton Mediated Strong Long-Distance Spin-Spin Coupling,"Strong long-distance spin-spin coupling is desperately demanded for
solid-state quantum information processing, but it is still challenged. Here,
we propose a hybrid quantum system, consisting of a coplanar waveguide (CPW)
resonator weakly coupled to a single nitrogen-vacancy spin in diamond and a
yttrium-iron-garnet (YIG) nanosphere holding Kerr magnons, to realize strong
long-distance spin-spin coupling. With a strong driving field on magnons, the
Kerr effect can squeeze magnons, and thus exponentially enhance the coupling
between the CPW resonator and the squeezed magnons, which produces two
cavity-magnon polaritons, i.e., the high-frequency polariton (HP) and
low-frequency polariton (LP). When the enhanced cavity-magnon coupling
approaches to the critical value, the spin is fully decoupled from the HP,
while the coupling between the spin and the LP is significantly improved. In
the dispersive regime, a strong spin-spin coupling is achieved with accessible
parameters, and the coupling distance can be up to $\sim$cm. Our proposal
provides a promising way to manipulate remote solid spins and perform quantum
information processing in weakly coupled hybrid systems.",2304.13553v2
2002-03-15,Modified spin-wave study of random antiferromagnetic-ferromagnetic spin chains,"We study the thermodynamics of one-dimensional quantum spin-1/2 Heisenberg
ferromagnetic system with random antiferromagnetic impurity bonds. In the
dilute impurity limit, we generalize the modified spin-wave theory for random
spin chains, where local chemical potentials for spin-waves in ferromagnetic
spin segments are introduced to ensure zero magnetization at finite
temperature. This approach successfully describes the crossover from behavior
of pure one-dimensional ferromagnet at high temperatures to a distinct Curie
behavior due to randomness at low temperatures. We discuss the effects of
impurity bond strength and concentration on the crossover and low temperature
behavior.",0203326v1
2003-10-20,Spin wave spectrum of a disordered double exchange model,"A double exchange model with quenched disorder for conduction electrons is
studied by field theoretical methods. By using a path integral formalism and
replica techniques based on it, an ensemble-averaged spin wave dispersion of
the localized spins is derived. It is shown that the spectrum of the spin wave
has gaps at the multiple of the Fermi wavenumber of the conduction electrons in
the presence of disorder, and hence, quenched disorder for electrons adds a
striking effect to the dynamics of the localized spins. In the strong disorder
limit, the present results suggest spin-glass like behavior due to the
frustration of the exchange coupling.",0310446v1
2005-12-24,Modified spin-wave theory of nuclear magnetic relaxation in one-dimensional quantum ferrimagnets: Three-magnon versus Raman processes,"Nuclear spin-lattice relaxation in one-dimensional Heisenberg ferrimagnets is
studied by means of a modified spin-wave theory. Calculating beyond the
first-order mechanism, where a nuclear spin directly interacts with spin waves
through the hyperfine coupling, we demonstrate that the
exchange-scattering-enhanced three-magnon nuclear relaxation may generally
predominate over the Raman one with increasing temperature and decreasing
field. Recent proton spin-lattice relaxation-time (T_1_) measurements on the
ferrimagnetic chain compound NiCu(C_7_H_6_N_2_O_6_)(H_2_O)_3_2H_2_O suggest
that the major contribution to 1/T_1_ be made by the three-magnon scattering.",0512629v1
2006-01-24,MnO Spin-Wave Dispersion Curves from Powder Diffraction Data,"We describe a model-independent approach for the extraction of spin-wave
dispersion curves from neutron total scattering data. The method utilises a
statistical analysis of real-space spin configurations to calculate
spin-dynamical quantities. The RMCProfile implementation of the reverse Monte
Carlo refinement process is used to generate a large ensemble of supercell spin
configurations from powder diffraction data. Our analysis of these
configurations gives spin-wave dispersion curves that agree well with those
determined independently using neutron triple-axis spectroscopic techniques.",0601558v2
2024-03-20,Electron wave spin in a cavity,"Our study reveals electron spin in a cavity as a stable circulating current
density, characterized by a torus topology. This current density circulates
concentrically beyond the cavity boundary, illustrating the concept of
evanescent wave spin. While the interaction with a uniform magnetic field
aligns with established spin-field observations, our analysis of regional
contributions deviates from particle-based spin predictions. The integration of
charge and spin properties into a single Lorentz covariant entity suggests that
the electron wave constitutes the fundamental and deterministic reality of the
electron.",2403.13696v1
2013-12-17,Dynamical resonance locking in tidally interacting binary systems,"We examine the dynamics of resonance locking in detached, tidally interacting
binary systems. In a resonance lock, a given stellar or planetary mode is
trapped in a highly resonant state for an extended period of time, during which
the spin and orbital frequencies vary in concert to maintain the resonance.
This phenomenon is qualitatively similar to resonance capture in planetary
dynamics. We show that resonance locks can accelerate the course of tidal
evolution in eccentric systems and also efficiently couple spin and orbital
evolution in circular binaries. Previous analyses of resonance locking have not
treated the mode amplitude as a fully dynamical variable, but rather assumed
the adiabatic (i.e. Lorentzian) approximation valid only in the limit of
relatively strong mode damping. We relax this approximation, analytically
derive conditions under which the fixed point associated with resonance locking
is stable, and further check these analytic results using numerical
integrations of the coupled mode, spin, and orbital evolution equations. These
show that resonance locking can sometimes take the form of complex limit cycles
or even chaotic trajectories. We provide simple analytic formulae that define
the binary and mode parameter regimes in which resonance locks of some kind
occur (stable, limit cycle, or chaotic). We briefly discuss the astrophysical
implications of our results for white dwarf and neutron star binaries as well
as eccentric stellar binaries.",1312.4966v2
2023-07-20,The loop-zag resonator: A loop-gap resonator design for improved sensitivity in electron-spin resonance experiments,"We present a novel design of loop-gap resonator, the loop-zag resonator, for
sub-X-band electron-spin resonance spectroscopy. The loop-zag design can
achieve improved coupling to small-sample spin systems through the improvement
of sample filling factor and RF $B_1$ field. By introducing ``zags'' to the
resonator's gap path, the capacitance is increased, accommodating a smaller
loop size and thereby a larger filling factor to maintain the requisite
resonant frequency. We present experimental spectra on five different
resonators, each with approximately the same resonant frequency of
$\sim2.9$~GHz, showing that an increase in the number of zags and reduction in
loop size gives rise to higher sensitivity. Finite-element simulations of these
resonators provide estimates of the improved filling factors obtained through
the addition of zags. The frequency range over which this loop-zag design is
practical enables a breadth of future applications in microwave engineering,
including ESR and ESR-like quantum information microwave techniques.",2307.11269v1
2021-08-11,Scattering of ultrastrong electromagnetic waves by magnetized particles,"Observations of powerful radio waves from neutron star magnetospheres raise
the question of how strong waves interact with particles in a strong background
magnetic field $B_{bg}$. This problem is examined by solving the particle
motion in the wave. Remarkably, waves with amplitudes $E_0>B_{bg}$ pump
particle energy via repeating resonance events, quickly reaching the radiation
reaction limit. As a result, the wave is scattered with a huge cross section.
This fact has implications for models of fast radio bursts and magnetars.
Particles accelerated in the wave emit gamma-rays, which can trigger an $e^\pm$
avalanche and, instead of silent escape, the wave will produce X-ray fireworks.",2108.05464v2
1997-07-29,Spin Wave Instability of Itinerant Ferromagnet,"We show variationally that instability of the ferromagnetic state in the
Hubbard model is largely controlled by softening of a long-wavelength spin-wave
excitation, except in the over-doped strong-coupling region where the
individual-particle excitation becomes unstable first. A similar conclusion is
drawn also for the double exchange ferromagnet. Generally the spin-wave
instability may be regarded as a precursor of the metal-insulator transition.",9707300v1
2002-04-09,Spatial resolution of spin waves in an ultra-cold gas,"We present the first spatially resolved images of spin waves in a gas. The
complete longitudinal and transverse spin field as a function of time and space
is reconstructed. Frequencies and damping rates for a standing-wave mode are
extracted and compared with theory.",0204182v1
2005-05-15,Spin Charge Recombination in Projected Wave Functions,"We find spin charge recombination is a generic feature of projected wave
functions. We find this effect is responsible for a series of differences
between mean field theory prediction and the result from projected wave
functions. We also find spin charge recombination plays an important role in
determining the dissipation of supercurrent, the quasiparticle properties and
the hole - hole correlation.",0505369v1
2016-04-22,Waves from an oscillating point source with a free surface in the presence of a shear current,"We investigate analytically the linearized water wave radiation problem for
an oscillating submerged point source in an inviscid shear flow with a free
surface. A constant depth is taken into account and the shear flow increases
linearly with depth. The surface velocity relative to the source is taken to be
zero, so that Doppler effects are absent. We solve the linearized Euler
equations to calculate the resulting wave field as well as its far-field
asymptotics. For values of the Froude number $F^2=\omega^2 D/g$ ($\omega$:
oscillation frequency, $D$ submergence depth) below a resonant value
$F^2_\text{res}$ the wave field splits cleanly into separate contributions from
regular dispersive propagating waves and non-dispersive ""critical waves""
resulting from a critical layer-like street of flow structures directly
downstream of the source. In the sub-resonant regime the regular waves behave
like sheared ring waves while the critical layer wave forms a street of a
constant width of order $D\sqrt{S/\omega}$ ($S$ is the shear flow vorticity)
and is convected downstream at the fluid velocity at the depth of the source.
When the Froude number approaches its resonant value, the the downstream
critical and regular waves resonate, producing a train of waves of linearly
increasing amplitude contained within a downstream wedge.",1604.06680v1
2023-03-22,Attenuating surface gravity waves by an array of submerged resonators: an experimental study,"We report on an experimental study of a device composed by an array of
submerged, reversed and periodic cylindrical pendula (resonators), whose
objective is the attenuation of surface gravity waves. The idea is inspired by
the concept of metamaterials, i.e. engineered structures designed to interact
with waves and manipulate their propagation properties. The study is performed
in a wave flume where single frequency waves are excited in a wide range of
frequencies. We explore various configurations of the device, measuring the
transmitted, reflected and dissipated energy of the waves. If the incoming wave
frequencies are sufficiently close to the natural frequency of the pendula, we
find a considerable wave attenuation effect, driven by viscous dissipative
mechanisms. This behaviour is enhanced by the number of resonators in the
array. Moreover, the device is also capable of reflecting the energy of
selected frequencies of the incoming waves. These frequencies can be predicted
by assuming the interactions involving at least three wave modes, including
higher harmonics, and are therefore associated with the distance between the
resonators. The presented results show promise for the development of a
environmentally sustainable device for mitigating waves in coastal zones.",2303.12646v1
2004-12-28,Resonant plasmon scattering by discrete breathers in Josephson junction ladders,"We study the resonant scattering of plasmons (linear waves) by discrete
breather excitations in Josephson junction ladders. We predict the existence of
Fano resonances, and find them by computing the resonant vanishing of the
transmission coefficient. We propose an experimental setup of detecting these
resonances, and conduct numerical simulations which demonstrate the possibility
to observe Fano resonances in the plasmon scattering by discrete breathers in
Josephson junction ladders.",0412727v1
2011-02-28,Resonant d-wave scattering in harmonic waveguides,"We observe and analyze d-wave resonant scattering of bosons in tightly
confining harmonic waveguides. It is shown that the d-wave resonance emerges in
the quasi-1D regime as an imprint of a 3D d-wave shape resonance. A scaling
relation for the position of the d-wave resonance is provided. By changing the
trap frequency, ultracold scattering can be continuously tuned from s-wave to
d-wave resonant behavior. The effect can be utilized for the realization of
ultracold atomic gases interacting via higher partial waves and opens a novel
possibility for studying strongly correlated atomic systems beyond s-wave
physics.",1102.5686v2
2011-05-30,Analytic description of atomic interaction at ultracold temperatures II: Scattering around a magnetic Feshbach resonance,"Starting from a multichannel quantum-defect theory, we derive analytic
descriptions of a magnetic Feshbach resonance in an arbitrary partial wave $l$,
and the atomic interactions around it. An analytic formula, applicable to both
broad and narrow resonances of arbitrary $l$, is presented for ultracold atomic
scattering around a Feshbach resonance. Other related issues addressed include
(a) the parametrization of a magnetic Feshbach resonance of arbitrary $l$, (b)
rigorous definitions of ""broad"" and ""narrow"" resonances of arbitrary $l$ and
their different scattering characteristics, and (c) the tuning of the effective
range and the generalized effective range by a magnetic field.",1105.5846v1
2013-12-14,Plasmon resonance and heat generation model in nanostructures,"In this paper, we investigate the photothermal effects of the plasmon
resonance. Metal nanoparticles efficiently generate heat in the presence of
electromagnetic radiation. The process is strongly enhanced when a fixed
frequency of the incident wave illuminate on nanoprticles such that plasmon
resonance happen. We shall introduce the electromagnetic radiation model and
show exactly how and when the plasmon resonance happen. We then construct the
heat generation and transfer model and derive the heat effect induced by
plasmon resonance. Finally, we consider the heat generation under plasmon
resonance in a concentric nanoshell structure.",1312.3994v1
2014-05-04,Separated spin-up and spin-down quantum hydrodynamics of degenerated electrons: spin-electron acoustic wave appearance,"Quantum hydrodynamic (QHD) model of charged spin-1/2 particles contains
physical quantities defined for all particles of a species including particles
with spin-up and with spin-down. Different population of states with different
spin direction is included in the spin density (magnetization). In this paper
we derive a QHD model, which separately describes spin-up electrons and
spin-down electrons. Hence we consider electrons with different projection of
spin on the preferable direction as two different species of particles. We show
that numbers of particles with different spin direction do not conserve. Hence
the continuity equations contain sources of particles. These sources are caused
by the interactions of spins with magnetic field. Terms of similar nature arise
in the Euler equation. We have that z-projection of the spin density is no
longer an independent variable. It is proportional to difference between
concentrations of electrons with spin-up and electrons with spin-down. In terms
of new model we consider propagation of waves in magnetized plasmas of
degenerate electrons and motionless ions. We show that new form of QHD
equations gives all solutions obtained from traditional form of QHD equations
with no distinguish of spin-up and spin-down states. But it also reveals a
sound-like solution we call the spin-electron acoustic wave. Coincidence of
most solutions is expected since we started derivation with the same basic
equation.",1405.0719v1
2004-08-05,'Swing Absorption' of fast magnetosonic waves in inhomogeneous media,"The recently suggested swing interaction between fast magnetosonic and Alfven
waves (Zaqarashvili and Roberts 2002) is generalized to inhomogeneous media. We
show that the fast magnetosonic waves propagating across an applied non-uniform
magnetic field can parametrically amplify the Alfven waves propagating along
the field through the periodical variation of the Alfven speed. The resonant
Alfven waves have half the frequency and the perpendicular velocity
polarization of the fast waves. The wave lengths of the resonant waves have
different values across the magnetic field, due to the inhomogeneity in the
Alfven speed. Therefore, if the medium is bounded along the magnetic field,
then the harmonics of the Alfven waves, which satisfy the condition for onset
of a standing pattern, have stronger growth rates. In these regions the fast
magnetosonic waves can be strongly 'absorbed', their energy going in
transversal Alfven waves. We refer to this phenomenon as 'Swing Absorption'.
This mechanism can be of importance in various astrophysical situations.",0408114v2
2007-05-16,On the tuning of a wave-energy driven oscillating-water-column seawater pump to polychromatic waves,"Performance of wave-energy devices of the oscillating water column (OWC) type
is greatly enhanced when a resonant condition with the forcing waves is
maintained. The natural frequency of such systems can in general be tuned to
resonate with a given wave forcing frequency. In this paper we address the
tuning of an OWC sea-water pump to polychromatic waves. We report results of
wave tank experiments, which were conducted with a scale model of the pump.
Also, a numerical solution for the pump equations, which were proven in
previous work to successfully describe its behavior when driven by
monochromatic waves, is tested with various polychromatic wave spectra. Results
of the numerical model forced by the wave trains measured in the wave tank
experiments are used to develop a tuning criterion for the sea-water pump.",0705.2297v1
2020-11-11,Numerical Simulation of Collinear Capillary-Wave Turbulence,"We report on direct numerical simulation of quasi-one-dimensional
bidirectional capillary-wave turbulence. Although nontrivial three-wave and
four-wave resonant interactions are absent in this peculiar geometry, we show
that an energy transfer between scales still occurs concentrated around the
linear dispersion relation that is broadened by nonlinearity. The wave spectrum
displays a clear wave number power-law scaling that is found to be in good
agreement with the dimensionally prediction for capillary-wave turbulence
involving four-wave interactions. The carried out high-order correlation
analysis (bicoherence and tricoherence) confirms quantitatively the dominant
role of four-wave quasi-resonant interactions. The Kolmogorov-Zakharov spectrum
constant is also estimated numerically. We interpret our results as the first
numerical observation of anisotropic capillary-wave turbulence in which
four-wave interactions play a dominant role",2011.05636v1
2021-11-22,Rogue Waves in (2+1)-Dimensional Three-Wave Resonant Interactions,"Rogue waves in (2+1)-dimensional three-wave resonant interactions are
studied. General rogue waves arising from a constant background, from a
lump-soliton background and from a dark-soliton background have been derived,
and their dynamics illustrated. For rogue waves arising from a constant
background, fundamental rogue waves are line-shaped, and multi-rogue waves
exhibit multiple intersecting lines. Higher-order rogue waves could also be
line-shaped, but they exhibit multiple parallel lines. For rogue waves arising
from a lump-soliton background, they could exhibit distinctive patterns due to
their interaction with the lump soliton. For rogue waves arising from a
dark-soliton background, their intensity pattern could feature half-line shapes
or lump shapes, which are very novel.",2111.11333v1
2004-04-21,Four-Wave Mixing In BEC Systems With Multiple Spin States,"We calculate the four-wave mixing (FWM) in a Bose-Einstein condensate system
having multiple spin wave packets that are initially overlapping in physical
space, but have nonvanishing relative momentum that cause them to recede from
one another. Three receding condensate atom wave packets can result in
production of a fourth wave packet by the process of FWM due to atom-atom
interactions. We consider cases where the four final wave packets are composed
of 1, 2, 3 and 4 different internal spin components. FWM with 1- or 2-spin
state wave packets is much stronger than 3- or 4-spin state FWM, wherein two of
the coherent moving BEC wave packets form a polarization-grating that rotates
the spin projection of the third wave into that of fourth diffracted wave (as
opposed to the 1- or 2-spin state case where a regular density-grating is
responsible for the diffraction). Calculations of FWM for $^{87}$Rb and
$^{23}$Na condensate systems are presented.",0404499v1
2018-08-16,Energy transfer in resonant and near-resonant internal wave triads for weakly non-uniform stratifications. Part I: Unbounded domain,"In this paper, using multiple scale analysis we derive a generalized
mathematical model for amplitude evolution, and for calculating the energy
exchange in resonant and near-resonant global triads consisting of weakly
nonlinear internal gravity wave packets in weakly non-uniform density
stratifications in an unbounded domain in the presence of viscous and
rotational effects. Such triad interactions are one of the mechanisms by which
high wavenumber internal waves lead to ocean turbulence and mixing via
parametric subharmonic instability. Non-uniform stratification introduces
detuning - mismatch in the vertical wavenumber triad condition, which may
strongly affect the energy transfer process. We investigate in detail how
factors like wave-packets' width, group speeds, nonlinear coupling
coefficients, detuning, and viscosity affect energy transfer in weakly varying
stratification. We find limitations of the well-known 'pump-wave approximation'
and derive a non-dimensional number, which can be evaluated from initial
conditions, that can predict the maximum energy transferred from the primary
wave during the later stages. Two additional non-dimensional numbers, based on
various factors affecting energy transfer between near-resonant wave-packets
have also been defined. Moreover, we identify the optimal background
stratification in a medium of varying stratification for the primary wave to
form a triad with no detuning so that the energy transfer is maximum. Finally,
we show that even a small change in the background stratification can cause a
significant difference in the energy transfer process between the wave-packets
when they have the same order of magnitude of energy.",1808.05591v5
2022-07-06,Is the resonant wave interaction approximation consistent with the dynamics of internal wave fields?,"Nonlinear interaction and breaking of internal ocean waves are responsible
for much of the interior ocean mixing, affecting ocean carbon storage and the
global overturning circulation. These interactions are also believed to dictate
the observed Garrett-Munk wave energy spectrum, which is still unexplained
after 50 years of studies. According to the resonant wave interaction
approximation, used to derive the kinetic equation for the energy spectrum, the
dominant interactions are between wave triads whose wavevectors satisfy
$\mathbf{k}=\mathbf{p}+\mathbf{q}$, and whose frequencies satisfy
$\omega_{\mathbf{k}}=|\omega_{\mathbf{p}}\pm\omega_{\mathbf{q}}|$. In order to
test the validity of the resonant wave interaction approximation, we examine
several analytical derivations of the theory. The assumptions underlying each
derivation are tested using idealized direct 2d numerical simulations,
representing near-observed energy levels of the oceanic internal wave field. We
show that the assumptions underlying the derivations are not consistent with
the simulated dynamics. In addition, most of the triads satisfying the resonant
conditions do not contribute significantly to nonlinear wave energy transfer in
our simulations, while some interactions that are dominant in nonlinear energy
transfers do not satisfy the resonance conditions. We also point to possible
self-consistency issues with some derivations found in the literature.",2207.02758v4
2021-05-25,Line Shapes of Electric Dipole Spin Resonance in Pauli Spin Blockade,"Electric dipole spin resonance (EDSR) is a commonly used tool for
manipulation and spectroscopy of quantum-dot-based spin qubits. When an EDSR
experiment is embedded in a transport setup and Pauli spin blockade is used as
means for spin-state read-out, then measured resonant responses in the leakage
current indeed carry information about the level structure of the system under
study. However, the actual line shape of these current resonances differs
substantially from experiment to experiment, varying from being symmetric to
asymmetric and from being a peak to a dip, a thorough understanding of which is
still lacking. Here, we investigate theoretically the detailed line shape of
EDSR-induced resonances in the leakage current in the regime of spin blockade,
and we connect different line shapes to the different underlying physical
mechanisms that can enable the EDSR. We carry out both numerical and analytical
investigations, producing simple analytic expressions that give insight in the
physics at play. Our results thus provide a means to extract more information
about the detailed system parameters of quantum dots hosting spin qubits from
an EDSR experiment than just their level structure based on the location of the
resonances.",2105.12088v2
2015-08-20,Origin of coda waves: earthquake source resonance,"Coda in local earthquake exhibits resonance-like wave behaviour where the
coda emerges as long-duration small-amplitude vibration with selective
frequency, slow temporal decay, and uniform spatial energy distribution around
the earthquake source. Coda is thought to be the incoherent waves scattered
from random small-scale heterogeneity in the earth's lithosphere. Here I show
that the coda is primarily attributed to the natural resonance in strong
small-scale heterogeneity around the earthquake's hypocenter through seismic
wave field modeling for 1D heterogeneity. The natural resonance is evolved from
the low frequency resonance (LFR) in transient regime and is an emergent
phenomenon that occurs in steady state regime. Its resonance frequency
decreases with increasing heterogeneous scale, impedance contrast, or random
heterogeneous scale and velocity fluctuations; its intensity diminishes with
decreasing impedance contrast or increasing random heterogeneous scale and
velocity fluctuations.",1508.04873v4
2023-03-14,"ECMI Resonance in AKR Revisited: Hyperbolic Resonance, Harmonics, Wave-Wave Interaction","Recapitulation of the resonance condition for the fundamental and higher
electron cyclotron harmonics in the Electron Cyclotron Maser Instability (ECMI)
enables radiation below and confirms the possibility of radiation in a narrow
band above harmonics $n>1$. Near $n=1$ resonance on the confined lower X-mode
branch, amplification is supported by the decrease of phase and group speeds.
Confined slow large-amplitude quasi-electrostatic X-modes nonlinearly modulate
the plasma to form cavitons until self-trapped inside them at further
increasing wavenumber. They undergo wave-wave interaction, enabling escape to
free space in the second harmonic band below $n=2$. At sufficiently large
parallel wavenumber (oblique propagation), the fundamental resonance $n=1$ is
hyperbolic, a possibility so far missed but vital for an effective ECMI in the
upward current region. Here, the resonance hyperbola favourably fits the loss
cone boundary, the presumably important ECMI upward-current source-electron
distribution, to stimulate ECMI growth at available auroral electron energies.",2303.07950v1
2004-09-11,Andreev reflection resonant tunneling through a precessing spin,"We investigate Andreev reflection (AR) resonant tunneling through a
precessing spin which is coupled to a normal metallic lead and a
superconducting lead. The formula of the AR conductance at zero temperature is
obtained as a function of chemical potential and azimuthal angle of the spin
precessing by using the nonequilibrium Green function method. It is found that
as the local spin precesses in a weak external magnetic field at Larmor
frequency $\omega_l$, the AR tunneling conductance exhibits an oscillation at
the frequency $2\omega_l$ alone. The amplitude of AR conductance oscillation
enhances with spin-flip tunneling coupling increasing. The study also shows
that spin-orbit interaction in tunneling barriers is crucial for the
oscillations of AR conductance. The effect of spin-flip tunneling coupling
caused by spin-orbit interaction and local spin precessing on resonant behavior
of the AR conductance are examined.",0409286v1
2005-03-19,"Correlations, spin dynamics, defects: the highly-frustrated Kagomé bilayer","The SrCr$\_{9p}$Ga$\_{12-9p}$O$\_{19}$ and
Ba$\_{2}$Sn$\_{2}$ZnGa$\_{10-7p}$Cr$\_{7p}$O$\_{22}$ compounds are two
highly-frustrated magnets possessing a quasi-two-dimensional Kagom\'{e} bilayer
of spin 3/2 chromium ions with antiferromagnetic interactions. Their magnetic
susceptibility was measured by local Nuclear Magnetic Resonance and non-local
(SQUID) techniques, and their low-temperature spin dynamics by Muon Spin
Resonance. Consistent with the theoretical picture drawn for geometrically
frustrated systems, the Kagom\'{e} bilayer is shown here to exhibit: (i) short
range spin-spin correlations down to a temperature much lower than the
Curie-Weiss temperature, no conventional long-range transition occurring; (ii)
a Curie contribution to the susceptibility from paramagnetic defects generated
by spin vacancies; (iii) low-temperature spin fluctuations, at least down to 30
mK, which are a trademark of a dynamical ground state. These properties point
to a spin-liquid ground state, possibly built on Resonating Valence Bonds with
unconfined spinons as the magnetic excitations.",0503496v1
2006-04-25,Multiple-pulse coherence enhancement of solid state spin qubits,"We describe how the spin coherence time of a localized electron spin in
solids, i.e. a solid state spin qubit, can be prolonged by applying designed
electron spin resonance pulse sequences. In particular, the spin echo decay due
to the spectral diffusion of the electron spin resonance frequency induced by
the non-Markovian temporal fluctuations of the nuclear spin flip-flop dynamics
can be strongly suppressed using multiple-pulse sequences akin to the
Carr-Purcell-Meiboom-Gill pulse sequence in nuclear magnetic resonance. Spin
coherence time can be enhanced by factors of 4-10 in GaAs quantum dot and Si:P
quantum computer architectures using composite sequences with an even number of
pulses.",0604577v2
2007-08-15,Spin dynamics in InAs-nanowire quantum-dots coupled to a transmission line,"We study theoretically electron spins in nanowire quantum dots placed inside
a transmission line resonator. Because of the spin-orbit interaction, the spins
couple to the electric component of the resonator electromagnetic field and
enable coherent manipulation, storage, and read-out of quantum information in
an all-electrical fashion. Coupling between distant quantum-dot spins, in one
and the same or different nanowires, can be efficiently performed via the
resonator mode either in real time or through virtual processes. For the latter
case we derive an effective spin-entangling interaction and suggest means to
turn it on and off. We consider both transverse and longitudinal types of
nanowire quantum-dots and compare their manipulation timescales against the
spin relaxation times. For this, we evaluate the rates for spin relaxation
induced by the nanowire vibrations (phonons) and show that, as a result of
phonon confinement in the nanowire, this rate is a strongly varying function of
the spin operation frequency and thus can be drastically reduced compared to
lateral quantum dots in GaAs. Our scheme is a step forward to the formation of
hybrid structures where qubits of different nature can be integrated in a
single device.",0708.2091v1
2008-07-16,Theory of electric dipole spin resonance in quantum dots: Mean field theory with Gaussian fluctuations and beyond,"Very recently, the electric dipole spin resonance (EDSR) of single electrons
in quantum dots was discovered by three independent experimental groups.
Remarkably, these observations revealed three different mechanisms of EDSR:
coupling of electron spin to its momentum (spin-orbit), to the operator of its
position (inhomogeneous Zeeman coupling), and to the hyperfine Overhauser field
of nuclear spins. In this paper, I present a unified microscopic theory of
these resonances in quantum dots. A mean field theory, derived for all three
mechanisms and based on retaining only two-spin correlators, justifies applying
macroscopic description of nuclear polarization to the EDSR theory. In the
framework of the mean field theory, a fundamental difference in the time
dependence of EDSR inherent of these mechanisms is revealed; it changes from
the Rabi-type oscillations to a nearly monotonic growth. The theory provides a
regular procedure to account for the higher nuclear-spin correlators that
become of importance for a wider time span and can change the asymptotic
behavior of EDSR. It also allows revealing the effect of electron spin dynamics
on the effective coupling between nuclear spins.",0807.2624v1
2015-03-03,Electron Spin Resonance Spectroscopy via Relaxation of Solid-State Spin Probes at the Nanoscale,"Electron Spin Resonance (ESR) describes a suite of techniques for
characterising electronic systems, with applications in physics, materials
science, chemistry, and biology. However, the requirement for large electron
spin ensembles in conventional ESR techniques limits their spatial resolution.
Here we present a method for measuring the ESR spectrum of nanoscale electronic
environments by measuring the relaxation time ($T_1$) of an optically addressed
single-spin probe as it is systematically tuned into resonance with the target
electronic system. As a proof of concept we extract the spectral distribution
for the P1 electronic spin bath in diamond using an ensemble of
nitrogen-vacancy centres, and demonstrate excellent agreement with theoretical
expectations. As the response of each NV spin in this experiment is dominated
by a single P1 spin at a mean distance of 2.7\,nm, the extension of this
all-optical technique to the single NV case will enable nanoscale ESR
spectroscopy of atomic and molecular spin systems.",1503.00830v1
2019-10-29,Spin noise at electron paramagnetic resonance,"We develop a microscopic theory of spin noise in solid-state systems at
electron paramagnetic resonance, when the spin dynamics is driven by static and
radio-frequency (RF) magnetic fields and the stochastic effective magnetic
field stemming from the interaction with environment. The RF field splits the
peaks in the power spectrum of spin noise into the Mollow-like triplets and
also gives rise to additional spin-spin correlations which oscillate in the
absolute time at the RF frequency and the double frequeqncy. Even in systems
with strong inhomogeneous broadening, the spin noise spectrum contains narrow
lines insensitive to the dispersion of the effective $g$-factors. Thus, the
measurements of spin noise at electron paramagnetic resonance provides an
access to the intrinsic spin lifetime of electrons.",1910.13167v1
2020-02-06,Search for exotic spin-dependent interactions using polarized helium,"We investigate the sensitivities of searches for exotic spin-dependent
interactions between the polarized nuclear spins of $^3$He and the particles of
unpolarized or polarized solid-state masses using the frequency method and the
resonance method. In the frequency method, the spin-dependent interactions act
as an effective static magnetic field, causing the frequency shift to the spin
precession of $^{3}$He. In the resonance method, proposed by Arvanitaki and
Geraci [Phys. Rev. Lett. 113, 161801 (2014)] for the significant improvement of
the experimental sensitivities on the spin-dependent interactions, the mass
movement is modulated at the Larmor frequency of $^3$He. This results in the
modulating spin-dependent interactions inducing an effective oscillatory
magnetic field, which can tilt the $^3$He spins, similarly as an oscillatory
magnetic field in nuclear magnetic resonance. We estimate the sensitivities of
the searches using a room-temperature $^3$He target for its extremely long
relaxation time. New limits on the coupling strengths of the spin-dependent
interactions can be set in the interaction length range below $10^{-1}$ m.",2002.02495v3
2022-10-06,Electrically-detected single-spin resonance with Quantum Spin Hall edge states,"Detection is most often the main impediment to reduce the number of spins in
paramagnetic resonance experiments. Here we propose a new route to carry out
electrically-detected spin resonance of an individual spin, placed at the edge
of a quantum spin Hall insulator (QSHI). The edges of a QSHI host a one
dimensional electron gas with perfect spin-momentum locking. Therefore, the
spin relaxation induced by emission of an electron-hole pair at the edge state
of the QSHI can generate current. Here we demonstrate that driving the system
with an $AC$ signal, a nonequilibrium occupation can be induced in the absence
of applied bias voltage, resulting in a $DC$ measurable current. We compute the
$DC$ current as a function of the Rabi frequency $\Omega$, the spin relaxation
and decoherence times, $T_1$ and we discuss the feasibility of this experiment
with state-of-the-art instrumentation.",2210.02917v1
2005-01-09,Nonequilibrium Kondo Effect in a Quantum Dot Coupled to Ferromagnetic Leads,"We study the Kondo effect in the electron transport through a quantum dot
coupled to ferromagnetic leads, using a real-time diagrammatic technique which
provides a systematic description of the nonequilibrium dynamics of a system
with strong local electron correlations. We evaluate the theory in an extension
of the `resonant tunneling approximation', introduced earlier, by introducing
the self-energy of the off-diagonal component of the reduced propagator in spin
space. In this way we develop a charge and spin conserving approximation that
accounts not only for Kondo correlations but also for the spin splitting and
spin accumulation out of equilibrium. We show that the Kondo resonances, split
by the applied bias voltage, may be spin polarized. A left-right asymmetry in
the coupling strength and/or spin polarization of the electrodes significantly
affects both the spin accumulation and the weight of the split Kondo resonances
out of equilibrium. The effects are observable in the nonlinear differential
conductance. We also discuss the influence of decoherence on the Kondo
resonance in the frame of the real-time formulation.",0501172v1
2007-12-07,Exchange effects in elastic collisions of spin-polarized electrons with open-shell molecules with $^3Σ_g^-$ symmetry,"The spin-exchange effect in spin-polarized electron collisions with
unpolarized open-shell molecules, O$_2$, B$_2$, S$_2$ and Si$_2$, has been
studied by the R-matrix method with the fixed-bond approximation. All of these
molecules have ${}^3 \Sigma_{g}^{-}$ symmetry in their ground states. Usual
integrated cross sections with unpolarized electrons has also been studied. We
used the complete active space self consistent field orbitals and put more than
10 target electronic states in the R-matrix models. In electron O$_2$ elastic
collisions, calculated polarization fractions agree well with the experimental
results, especially around the ${}^4 \Sigma_u^-$ resonance. In e-B$_2$, S$_2$
and Si$_2$ elastic collisions, larger spin-exchange effect is observed compared
to the e-O$_2$ elastic collisions. In all four cases, spin-exchange effect
becomes prominent near resonances. This association of resonance and magnitude
of the spin-exchange effect was studied by explicitly removing the resonance
configurations from the R-matrix calculations. In general, spin-exchange effect
is larger in e-B$_2$ collisions than in e-S$_2$ and Si$_2$ collisions, and is
smallest in e-O$_2$ collisions.",0712.1068v1
2009-02-16,Locking electron spins into magnetic resonance by electron-nuclear feedback,"The main obstacle to coherent control of two-level quantum systems is their
coupling to an uncontrolled environment. For electron spins in III-V quantum
dots, the random environment is mostly given by the nuclear spins in the
quantum dot host material; they collectively act on the electron spin through
the hyperfine interaction, much like a random magnetic field. Here we show that
the same hyperfine interaction can be harnessed such that partial control of
the normally uncontrolled environment becomes possible. In particular, we
observe that the electron spin resonance frequency remains locked to the
frequency of an applied microwave magnetic field, even when the external
magnetic field or the excitation frequency are changed. The nuclear field
thereby adjusts itself such that the electron spin resonance condition remains
satisfied. General theoretical arguments indicate that this spin resonance
locking is accompanied by a significant reduction of the randomness in the
nuclear field.",0902.2659v1
2011-10-19,Fano resonances and electron spin transport through a two-dimensional spin-orbit-coupled quantum ring,"Electron transport through a spin-orbit-coupled quantum ring is investigated
within linear response theory. We show that the finite width of the ring
results in the appearance of Fano resonances in the conductance. This turns out
to be a consequence of the spin-orbit interaction that leads to a breaking of
the parity of the states localized in the ring. The resonances appear when the
system is close to maxima of Aharonov-Casher conductance oscillations where
spin transfer is heavily modified. When the spin-orbit coupling strength is
detuned from the Aharonov-Casher maxima the resonances are broadened resulting
in a dependence of the spin transport on the electron Fermi energy in contrast
to predictions from one-dimensional models",1110.4233v1
2012-10-08,Intrinsic oscillations of spin current polarization in a paramagnetic resonant tunneling diode,"A spin- and time-dependent electron transport has been studied in a
paramagnetic resonant tunneling diode using the self-consistent Wigner-Poisson
method. Based on the calculated current-voltage characteristics in an external
magnetic field we have demonstrated that under a constant bias both the spin-up
and spin-down current components exhibit the THz oscillations in two different
bias voltage regimes. We have shown that the oscillations of the spin-up (down)
polarized current result from the coupling between the two resonance states:
one localized in the triangular quantum well created in the emitter region and
the second localized in the main quantum well. We have also elaborated the
one-electron model of the current oscillations, which confirms the results
obtained with the Wigner-Poisson method. The spin current oscillations can
lower the effectiveness of spin filters based on the paramagnetic resonant
tunneling structures and can be used to design the generators of the spin
polarized current THz oscillations that can operate under the steady bias and
constant magnetic field.",1210.2280v2
2013-02-15,Spin dynamics of a Mn atom in a semiconductor quantum dot under resonant optical excitation,"We analyze the spin dynamics of an individual magnetic atom (Mn) inserted in
a II-VI semiconductor quantum dot under resonant optical excitation. In
addition to standard optical pumping expected for a resonant excitation, we
show that for particular conditions of laser detuning and excitation intensity,
the spin population can be trapped in the state which is resonantly excited.
This effect is modeled considering the coherent spin dynamics of the coupled
electronic and nuclear spin of the Mn atom optically dressed by a resonant
laser field. This spin population trapping mechanism is controlled by the
combined effect of the coupling with the laser field and the coherent
interaction between the different Mn spin states induced by an anisotropy of
the strain in the plane of the quantum dot.",1302.3769v1
2014-10-02,Non-Markovian dynamics of a single-mode cavity strongly coupled to an inhomogeneously broadened spin ensemble,"We study the dynamics of a spin ensemble strongly coupled to a single-mode
resonator driven by external pulses. When the mean frequency of the spin
ensemble is in resonance with the cavity mode, damped Rabi oscillations are
found between the spin ensemble and the cavity mode which we describe very
accurately, including the dephasing effect of the inhomogeneous spin
broadening. We demonstrate that a precise knowledge of this broadening is
crucial both for a qualitative and a quantitative understanding of the temporal
spin-cavity dynamics. On this basis we show that coherent oscillations between
the spin ensemble and the cavity can be enhanced by a few orders of magnitude,
when driving the system with pulses that match special resonance conditions.
Our theoretical approach is tested successfully with an experiment based on an
ensemble of negatively charged nitrogen-vacancy (NV) centers in diamond
strongly coupled to a superconducting coplanar single-mode waveguide resonator.",1410.0728v1
2017-12-18,Non-exponential decoherence of radio-frequency resonance rotation of spin in storage rings,"Precision experiments, such as the search for electric dipole moments of
charged particles using radiofrequency spin rotators in storage rings, demand
for maintaining the exact spin resonance condition for several thousand
seconds. Synchrotron oscillations in the stored beam modulate the spin tune of
off-central particles, moving it off the perfect resonance condition set for
central particles on the reference orbit. Here we report an analytic
description of how synchrotron oscillations lead to non-exponential decoherence
of the radiofrequency resonance driven up-down spin rotations. This
non-exponential decoherence is shown to be accompanied by a nontrivial walk of
the spin phase. We also comment on sensitivity of the decoherence rate to the
harmonics of the radiofreqency spin rotator and a possibility to check
predictions of decoherence-free magic energies.",1712.06485v1
2019-05-01,Flopping-mode electric dipole spin resonance,"Traditional approaches to controlling single spins in quantum dots require
the generation of large electromagnetic fields to drive many Rabi oscillations
within the spin coherence time. We demonstrate ""flopping-mode"" electric dipole
spin resonance, where an electron is electrically driven in a Si/SiGe double
quantum dot in the presence of a large magnetic field gradient. At zero
detuning, charge delocalization across the double quantum dot enhances coupling
to the drive field and enables low power electric dipole spin resonance.
Through dispersive measurements of the single electron spin state, we
demonstrate a nearly three order of magnitude improvement in driving efficiency
using flopping-mode resonance, which should facilitate low power spin control
in quantum dot arrays.",1905.00346v1
2021-08-10,Zero-field spin resonance in graphene with proximity-induced spin-orbit coupling,"We investigate collective spin excitations in graphene with proximity-induced
spin-orbit coupling (SOC) of the Rashba and valley-Zeeman types, as it is the
case, e.g., for graphene on transition- metal-dichalcogenide substrates. It is
shown that, even in the absence of an external magnetic field, such a system
supports collective modes, which correspond to coupled oscillations of the
uniform and valley-staggered magnetizations. These modes can be detected via
both zero-field electron spin resonance (ESR) and zero-field electric-dipole
spin resonance (EDSR), with EDSR response coming solely from Rashba SOC. We
analyze the effect of electron-electron interaction within the Fermi- liquid
kinetic equation and show that the interaction splits both the ESR and EDSR
peaks into two. The magnitude of splitting and the relative weights of the
resonances can be used to extract the spin-orbit coupling constants and
many-body interaction parameters that may not be accessible by other methods.",2108.04420v1
2023-02-09,Calorimetric measurement of nuclear spin-lattice relaxation rate in metals,"The quasiparticle density of states in correlated and quantum-critical metals
directly probes the effect of electronic correlations on the Fermi surface.
Measurements of the nuclear spin-lattice relaxation rate provide one such
experimental probe of quasiparticle mass through the electronic density of
states. By far the most common way of accessing the spin-lattice relaxation
rate is via nuclear magnetic resonance and nuclear quadrupole resonance
experiments, which require resonant excitation of nuclear spin transitions.
Here we report non-resonant access to spin-lattice relaxation dynamics in
AC-calorimetric measurements. The nuclear spin-lattice relaxation rate is
inferred in our measurements from its effect on the frequency dispersion of the
thermal response of the calorimeter-sample assembly. We use fast,
lithographically-defined nanocalorimeters to access the nuclear spin-lattice
relaxation times in metallic indium from 0.3~K to 7~K and in magnetic fields up
to 35~T.",2302.04442v2
2019-10-27,Tetraneutron resonance in the presence of a dineutron,"Background: Several previous studies provided contradicting results for the
four-neutron system, some claiming the existence of a 0+ near-threshold
resonance, others denying presence of any observable resonant states. Purpose:
Since most of the studies employed enhanced two-neutron interactions to follow
the evolution of an artificially bound state into a continuum one, we examine
several enhancement schemes that produce a bound dineutron as well. Methods: We
study the four-neutron system by solving exact four-particle equations. By
varying the interaction enhancement factor we calculate two-dineutron
scattering phase shifts and cross sections. Results: When the same enhancement
factor is used in all partial waves, a bound tetraneutron emerges together with
a strongly bound dineutron. Furthermore, such a 0+ tetraneutron evolves not
into a resonance but into a virtual state. Weak enhancement of S waves together
with strongly enhanced higher waves is needed for the emergence of the resonant
state. Anyhow the resonant behavior disappears well before reaching the
physical interaction strength. Conclusions: The interaction enhancement scheme
using the same factor for all waves, employed in several previous works, is
misleading for the search of 0+ resonance as only a virtual state can emerge.
Evolution of a bound tetraneutron into a resonance via an intermediate virtual
state is possible with strong enhancement of higher two-neutron waves.",1910.12333v1
2021-06-28,Resonance from antiferromagnetic spin fluctuations for superconductivity in UTe$_2$,"Superconductivity originates from the formation of bound (Cooper) pairs of
electrons that can move through the lattice without resistance below the
superconducting transition temperature $T_c$. Electron Cooper pairs in most
superconductors form anti-parallel spin singlets with total spin $S=0$,
although they can also form parallel spin-triplet Cooper pairs with $S=1$ and
an odd parity wavefunction. Spin-triplet pairing is important because it can
host topological states and Majorana fermions relevant for quantum computation.
Because spin-triplet pairing is usually mediated by ferromagnetic (FM) spin
fluctuations, uranium based materials near an FM instability are considered to
be ideal candidates for realizing spin-triplet superconductivity. Indeed,
UTe$_2$, which has a $T_c\approx 1.6$ K, has been identified as a candidate for
a chiral spin-triplet topological superconductor near an FM instability,
although it also has antiferromagnetic (AF) spin fluctuations. Here we use
inelastic neutron scattering (INS) to show that superconductivity in UTe$_2$ is
coupled to a sharp magnetic excitation, termed resonance, at the Brillouin zone
boundary near AF order. Because the resonance has only been found in
spin-singlet unconventional superconductors near an AF instability, its
observation in UTe$_2$ suggests that AF spin fluctuations may also induce
spin-triplet pairing or that electron pairing in UTe$_2$ has a spin-singlet
component.",2106.14424v2
2000-02-14,Spin-flux phase in the Kondo lattice model with classical localized spins,"We provide numerical evidence that a spin-flux phase exists as a ground state
of the Kondo lattice model with classical local spins on a square lattice. This
state manifests itself as a double-Q magnetic order in the classical spins with
spin density at both $(0,\pi)$ and $(\pi,0)$ and further exhibits fermionic
spin currents around an elementary plaquette of the square lattice. We examine
the spin-wave spectrum of this phase. We further discus an extension to a face
centered cubic (FCC) lattice where a spin-flux phase may also exist. On the FCC
lattice the spin-flux phase manifests itself as a triple-Q magnetically ordered
state and may exist in $\gamma$-Mn alloys.",0002211v1
2001-05-09,The Contribution of Hot Electron Spin Polarization to the Magnetotransport in a Spin-Valve Transistor at Finite Temperatures,"The effect of spin mixing due to thermal spin waves and temperature
dependence of hot electron spin polarization to the collector current in a
spin-valve transistor has been theoretically explored. We calculate the
collector current as well as the temperature dependence of magnetocurrent at
finite temperatures to investigate the relative importance of spin mixing and
hot electron spin polarization. In this study the inelastic scattering events
in ferromagnetic layers have been taken into account to explore our interests.
The theoretical calculations suggest that the temperature dependence of hot
electron spin polarization has substantial contribution to the magnetotransport
in the spin-valve transistor.",0105182v1
2007-01-31,Coupled spin-charge drift-diffusion approach for a two-dimensional electron gas with Rashba spin-orbit coupling,"Based on kinetic equations for the density matrix, drift-diffusion equations
are derived for a two-dimensional electron gas with Rashba spin-orbit coupling.
Universal results are obtained for the weak coupling case. Most interesting is
the observation that with increasing spin-orbit coupling strengths there is a
sharp transition between spin diffusion and ballistic spin transport. For
strong spin-orbit coupling, when the elastic scattering time is much larger
than the spin relaxation time, undamped spin-coherent waves are identified. The
existence of these long-lived spin-coherent states is confirmed by exact
analytical results obtained from microscopic kinetic equations valid in the
ballistic regime.",0701782v1
2009-04-13,Semiclassical spin transport in spin-orbit-coupled systems,"This article discusses spin transport in systems with spin-orbit interactions
and how it can be understood in a semiclassical picture. I will first present a
semiclassical wave-packet description of spin transport, which explains how the
microscopic motion of carriers gives rise to a spin current. Due to spin
non-conservation the definition of the spin current has some arbitrariness. In
the second part I will briefly review the physics from a density matrix point
of view, which makes clear the relationship between spin transport and spin
precession and the important role of scattering.",0904.1999v1
2010-10-29,Confinement-induced p-wave resonances from s-wave interactions,"We show that a purely s-wave interaction in three dimensions (3D) can induce
higher partial-wave resonances in mixed dimensions. We develop two-body
scattering theories in all three cases of 0D-3D, 1D-3D, and 2D-3D mixtures and
determine the positions of higher partial-wave resonances in terms of the 3D
s-wave scattering length assuming a harmonic confinement potential. We also
compute the low-energy scattering parameters in the p-wave channel (scattering
volume and effective momentum) that are necessary for the low-energy effective
theory of the p-wave resonance. We point out that some of the resonances
observed in the Florence group experiment [Phys. Rev. Lett. 104, 153202 (2010)]
can be interpreted as the p-wave resonances in the 2D-3D mixed dimensions. Our
study paves the way for a variety of physics, such as Anderson localization of
matter waves under p-wave resonant scatterers.",1011.0033v2
2023-01-20,Generation of photon pairs by spontaneous four-wave mixing in linearly uncoupled resonators,"We present a detailed study of the generation of photon pairs by spontaneous
four-wave mixing in a structure composed of two linearly uncoupled resonators,
where energy can be transferred from one resonator to another only through a
nonlinear interaction. Specifically, we consider the case of two
racetrack-shaped resonators connected by a coupler designed to guarantee that
the resonance comb of each resonator can be tuned independently, and to allow
the nonlinear interaction between modes that belong to different combs. We show
that such a coupler can be realized in at least two ways: a directional coupler
or a Mach-Zehnder interferometer. For these two scenarios, we derive analytic
expressions for the pair generation rate via single-pump spontaneous four-wave
mixing, and compare these results with that achievable in a single ring
resonator.",2301.08603v1
2023-07-30,The generation of high-energy electron-positron pairs during the Breit-Wheeler resonant process in a strong field of an X-ray electromagnetic wave,"The Breith-Wheeler resonant process has been theoretically studied in a
strong X-ray electromagnetic wave field under conditions when the energy of one
of the initial high-energy gamma quanta passes into the energy of a positron or
electron. These resonant conditions have been studied in detail. Analytical
formulas for the resonant differential cross-section of channels A and B of the
reaction are obtained. It is shown that the resonant differential cross-section
significantly depends on the value of the characteristic Breit-Wheeler energy,
which is determined by the parameters of the electromagnetic wave and the
initial gamma quanta. With a decrease in the characteristic Breit-Wheeler
energy, the resonant cross-section increases sharply and may exceed the
corresponding non-resonant cross-section by several orders of magnitude.",2308.02520v1
2000-10-31,Few-body resonances in light nuclei,"We have localized several few-body resonances in light nuclei, using methods
which can properly handle two- or three-body resonant states. Among other
results, we predict the existence of a three-neutron resonance, small
spin-orbit splittings between the low-lying states in He-5 and Li-5, the
nonexistence of the soft dipole resonance in He-6, new 1+ states in Li-8 and
B-8, and the presence of a nonlinear amplification phenomenon in the 0+_2 state
of C-12.",0010105v1
2016-07-08,Resonant electron-phonon-electron interaction,"The effect of the resonance of electron scattering energy difference and
phonon energy on the electron-phonon-electron interaction (EPEI) is studied.
Results show that the resonance of electron transition energy and phonon energy
can enhance EPEI by a magnitude of 1 to 2. Moreover, the anisotropic S-wave
electron or dx2-y2 electron can enhance resonance EPEI, and the self-energy
correction of the electron will weaken resonance EPEI. Particularly, the
asymmetrical spin-flip scattering process in k space can reduce the effect of
electronic self-energy to enhance resonance EPEI",1607.02338v1
2018-03-30,Resonance in the $Y_{c}N$ potential model,"We calculate two-body $J^{\pi}=0^{+}, 1^{+}$, and $J^{\pi}=2^{+}$ resonance
states of $Y_{c}$ ($= \Lambda_{c}$, $\Sigma_{c}$, or $\Sigma_{c}^{*}$) and $N$
using the complex scaling method. We employ the $Y_{c}N$-CTNN potentials, which
were proposed in our previous study, and obtain four resonances near
$\Sigma_{c}N$ and $\Sigma_{c}^{*}N$ thresholds. From the analysis by the
binding energies of partial channel systems, we conclude that these resonance
states are Feshbach resonances. We compare the results with the $Y_{c}N$
resonance states in the heavy quark limit, where the $\Sigma_{c}N$ and
$\Sigma_{c}^{*}N$ thresholds are degenerate, and find that they form two pairs
of the heavy-quark doublets in agreement with the heavy quark spin symmetry.",1803.11349v1
2023-01-05,Resonant triad interactions of gravity waves in cylindrical basins,"We present the results of a theoretical investigation into the existence,
evolution and excitation of resonant triads of nonlinear free-surface gravity
waves confined to a cylinder of finite depth. It is well known that resonant
triads are impossible for gravity waves in laterally unbounded domains; we
demonstrate, however, that horizontal confinement of the fluid may induce
resonant triads for particular fluid depths. For any three correlated wave
modes arising in a cylinder of arbitrary cross-section, we prove necessary and
sufficient conditions for the existence of a depth at which nonlinear resonance
may arise, and show that the resultant critical depth is unique. We enumerate
the low-frequency triads for circular cylinders, including a new class of
resonances between standing and counter-propagating waves, and also briefly
discuss annular and rectangular cylinders. Upon deriving the triad amplitude
equations for a finite-depth cylinder of arbitrary cross-section, we deduce
that the triad evolution is always periodic, and determine parameters
controlling the efficiency of energy exchange. In order to excite a particular
triad, we explore the influence of external forcing; in this case, the triad
evolution may be periodic, quasi-periodic, or chaotic. Finally, our results
have potential implications on resonant water waves in man-made and natural
basins, such as industrial-scale fluid tanks, harbours and bays.",2301.02163v2
2024-02-18,Polarization-dependent resonant phenomena in all-dielectric scatterers: inversion of magnetic inductance and electric displacement,"The theoretical description and experimental verification of resonant
phenomena in electromagnetic fields generated in the near zone of
all-dielectric rectangular thin sub wavelength frames, subjected to an incident
microwave, is considered. The geometry of considered problems is presented by
means of arrangements of these frames in three orthogonal planes, normal
respectively to electric component, magnetic component and wave vector of the
incident wave. Such trio paves the way to design of 3D all-dielectric
multiresonant microwave unit cell. Displacement currents, generated by linearly
polarized electromagnetic waves in the system, lead to the formation of
magnetic and electric dipoles, each of which possess own resonant frequency.
Resonant inversion of magnetic inductance and electric displacement is
observed. The sliding incidence of plane wave on the frame is shown to provide
the sharp and deep resonance in the components of generated field. The phase
shift equal to $\pi$ between the magnetic components of incident and generated
wave indicates the formation of negative magnetic response. There observes the
angular anisotropy of arising dipoles, manifested in values of resonance
frequencies and in the dependence of depths of resonant spectral dips upon the
orientation of dipoles, with respect to the direction of propagation of
incident wave.",2402.11509v1
2018-08-19,On Bragg resonances and wave triad interactions in two-layered shear flows,"The standard resonance conditions for Bragg scattering as well as weakly
nonlinear wave triads have been traditionally derived in the absence of any
background velocity. In this paper, we have studied how these resonance
conditions get modified when uniform, as well as various piecewise linear
velocity profiles, are considered for two-layered shear flows. Background
velocity can influence the resonance conditions in two ways (i) by causing
Doppler shifts, and (ii) by changing the intrinsic frequencies of the waves.
For Bragg resonance, even a uniform velocity field changes the resonance
condition. Velocity shear strongly influences the resonance conditions since,
in addition to changing the intrinsic frequencies, it can cause unequal Doppler
shifts between the surface, pycnocline, and the bottom. Using multiple scale
analysis and Fredholm alternative, we analytically obtain the equations
governing both the Bragg resonance and the wave triads. We have also extended
the Higher Order Spectral method, a highly efficient computational tool usually
used to study triad and Bragg resonance problems, to incorporate the effect of
piecewise linear velocity profile. A significant aspect, both in theoretical
and numerical fronts, has been extending the potential flow approximation,
which is the basis of studying these kinds of problems, to incorporate
piecewise constant background shear.",1808.06236v3
2008-06-13,Control of scroll wave turbulence using resonant perturbations,"Turbulence of scroll waves is a sort of spatio-temporal chaos that exists in
three-dimensional excitable media. Cardiac tissue and the Belousov-Zhabotinsky
reaction are examples of such media. In cardiac tissue, chaotic behaviour is
believed to underlie fibrillation which, without intervention, precedes cardiac
death. In this study we investigate suppression of the turbulence using
stimulation of two different types, ""modulation of excitability"" and ""extra
transmembrane current"". With cardiac defibrillation in mind, we used a single
pulse as well as repetitive extra current with both constant and feedback
controlled frequency. We show that turbulence can be terminated using either a
resonant modulation of excitability or a resonant extra current. The turbulence
is terminated with much higher probability using a resonant frequency
perturbation than a non-resonant one. Suppression of the turbulence using a
resonant frequency is up to fifty times faster than using a non-resonant
frequency, in both the modulation of excitability and the extra current modes.
We also demonstrate that resonant perturbation requires strength one order of
magnitude lower than that of a single pulse, which is currently used in
clinical practice to terminate cardiac fibrillation. Our results provide a
robust method of controlling complex chaotic spatio-temporal processes.
Resonant drift of spiral waves has been studied extensively in two dimensions,
however, these results show for the first time that it also works in three
dimensions, despite the complex nature of the scroll wave turbulence.",0806.2262v2
2023-12-14,Towards Inductive Robustness: Distilling and Fostering Wave-induced Resonance in Transductive GCNs Against Graph Adversarial Attacks,"Graph neural networks (GNNs) have recently been shown to be vulnerable to
adversarial attacks, where slight perturbations in the graph structure can lead
to erroneous predictions. However, current robust models for defending against
such attacks inherit the transductive limitations of graph convolutional
networks (GCNs). As a result, they are constrained by fixed structures and do
not naturally generalize to unseen nodes. Here, we discover that transductive
GCNs inherently possess a distillable robustness, achieved through a
wave-induced resonance process. Based on this, we foster this resonance to
facilitate inductive and robust learning. Specifically, we first prove that the
signal formed by GCN-driven message passing (MP) is equivalent to the
edge-based Laplacian wave, where, within a wave system, resonance can naturally
emerge between the signal and its transmitting medium. This resonance provides
inherent resistance to malicious perturbations inflicted on the signal system.
We then prove that merely three MP iterations within GCNs can induce signal
resonance between nodes and edges, manifesting as a coupling between nodes and
their distillable surrounding local subgraph. Consequently, we present Graph
Resonance-fostering Network (GRN) to foster this resonance via learning node
representations from their distilled resonating subgraphs. By capturing the
edge-transmitted signals within this subgraph and integrating them with the
node signal, GRN embeds these combined signals into the central node's
representation. This node-wise embedding approach allows for generalization to
unseen nodes. We validate our theoretical findings with experiments, and
demonstrate that GRN generalizes robustness to unseen nodes, whilst maintaining
state-of-the-art classification accuracy on perturbed graphs.",2312.08651v1
2017-08-01,Gravitational Wave Searches for Aligned-Spin Binary Neutron Stars Using Nonspinning Templates,"We study gravitational wave searches for merging binary neutron stars (NSs).
We use nonspinning template waveforms towards the signals emitted from
aligned-spin NS-NS binaries, in which the spins of the NSs are aligned with the
orbital angular momentum. We use the TaylorF2 waveform model, which can
generate inspiral waveforms emitted from aligned-spin compact binaries. We
employ the single effective spin parameter $\chi_{\rm eff}$ to represent the
effect of two component spins ($\chi_1, \chi_2$) on the wave function. For a
target system, we choose a binary consisting of the same component masses of
$1.4 M_{\odot}$ and consider the spins up to $\chi_i= 0.4$, We investigate
fitting factors of the nonspinning templates to evaluate their efficiency in
gravitational wave searches for the aligned-spin NS-NS binaries. We find that
the templates can achieve the fitting factors exceeding $0.97$ only for the
signals in the range of $-0.2 \lesssim \chi_{\rm eff} \lesssim 0$. Therefore,
we demonstrate the necessity of using aligned-spin templates not to lose the
signals outside that range. We also show how much the recovered total mass can
be biased from the true value depending on the spin of the signal.",1708.00426v1
2016-12-13,Spin precession and spin waves in a chiral electron gas: beyond Larmor's theorem,"Larmor's theorem holds for magnetic systems that are invariant under spin
rotation. In the presence of spin-orbit coupling this invariance is lost and
Larmor's theorem is broken: for systems of interacting electrons, this gives
rise to a subtle interplay between the spin-orbit coupling acting on individual
single-particle states and Coulomb many-body effects. We consider a
quasi-two-dimensional, partially spin-polarized electron gas in a semiconductor
quantum well in the presence of Rashba and Dresselhaus spin-orbit coupling.
Using a linear-response approach based on time-dependent density-functional
theory, we calculate the dispersions of spin-flip waves. We obtain analytic
results for small wave vectors and up to second order in the Rashba and
Dresselhaus coupling strengths $\alpha$ and $\beta$. Comparison with
experimental data from inelastic light scattering allows us to extract $\alpha$
and $\beta$ as well as the spin-wave stiffness very accurately. We find
significant deviations from the local density approximation for spin-dependent
electron systems.",1612.04314v1
2003-05-13,Structure of positive energy states in a deformed mean-field potential,"We investigate the properties of single-particle resonances in a
non-spherical potential by solving the coupled-channels equations for the
radial wave functions. We first generalize the box discretization method for
positive energy states to a deformed system. As in the spherical case, we find
that the discretized energy is stabilized against the box size when a resonance
condition is met. Using the wave functions thus obtained, we then discuss the
energy and the radial dependences of scattering wave functions in the vicinity
of an isolated resonance. In the eigenchannel basis, where the $S$-matrix is
diagonal, we propose a generalized expression for the factorization formula for
the multi-channel wave function. We find that the factorized wave function
agrees well with the exact solution inside the centrifugal barrier when the
energy distance from the resonance is less than the resonance width.",0305034v2
2003-10-02,Double-resonant extremely asymmetrical scattering of electromagnetic waves in periodic arrays separated by a gap,"Two strong simultaneous resonances of scattering--double-resonant extremely
asymmetrical scattering (DEAS)--are predicted in two parallel, oblique,
periodic Bragg arrays separated by a gap, when the scattered wave propagates
parallel to the arrays. One of these resonances is with respect to frequency
(which is common to all types of Bragg scattering), and another is with respect
to phase variation between the arrays. The diffractional divergence of the
scattered wave is shown to be the main physical reason for DEAS in the
considered structure. Although the arrays are separated, they are shown to
interact by means of the diffractional divergence of the scattered wave across
the gap from one array into the other. It is also shown that increasing
separation between the two arrays results in a broader and weaker resonance
with respect to phase shift. The analysis is based on a recently developed new
approach allowing for the diffractional divergence of the scattered wave inside
and outside the arrays. Physical interpretations of the predicted features of
DEAS in separated arrays are also presented. Applicability conditions for the
developed theory are derived.",0310011v1
2007-12-21,On gravitational-electromagnetic resonance,"This is an English translation of the paper M.B.Mensky, in: K.P.Stanyukovich
(ed.), ""Problems of Theory of Gravity and Elementary Particles"", issue 6,
Moscow, Atomizdat, 1975, p.181-190 (in Russian). This paper elaborates further
the idea (formulated in 1971 by Braginsky and Mensky) of detecting
high-frequency gravitational waves by observing resonance action of a
gravitational wave on the electromagnetic wave in a closed resonator
(waveguide). The phenomenon underlying such a detector was called
gravitational-electromagnetic resonance (GER). In the present paper both closed
(for example circular) resonator or waveguide and long (for example in the
shape of a spiral) waveguide are considered as possible gravitational-wave
detectors. High-frequency gravitational-wave detectors are now again actual
(see A.M.Cruise and R.M.J.Ingley, Class. Quant. Grav. 22, S479, 2005), but the
current literature on this topic does not cover all the issues discussed in the
present paper.",0712.3721v1
2008-03-23,Resonant interactions of nonlinear water waves in a finite basin,"We study exact four-wave resonances among gravity water waves in a square box
with periodic boundary conditions. We show that these resonant quartets are
linked with each other by shared Fourier modes in such a way that they form
independent clusters. These clusters can be formed by two types of quartets:
(1) {\it angle-resonances} which cannot directly cascade energy but which can
redistribute it among the initially excited modes and (2) {\it
scale-resonances} which are much more rare but which are the only ones that can
transfer energy between different scales. We find such resonant quartets and
their clusters numerically on the set of 1000 x 1000 modes, classify and
quantify them and discuss consequences of the obtained cluster structure for
the wavefield evolution. Finite box effects and associated resonant interaction
among discrete wave modes appear to be important in most numerical and
laboratory experiments on the deep water gravity waves, and our work is aimed
at aiding the interpretation of the experimental and numerical data.",0803.3308v2
2010-07-22,Couplings in coupled channels versus wave functions in the case of resonances: application to the two $Λ(1405)$ states,"In this paper we develop a formalism to evaluate wave functions in momentum
and coordinate space for the resonant states dynamically generated in a unitary
coupled channel approach. The on shell approach for the scattering matrix,
commonly used, is also obtained in Quantum Mechanics with a separable
potential, which allows one to write wave functions in a trivial way. We
develop useful relationships among the couplings of the dynamically generated
resonances to the different channels and the wave functions at the origin. The
formalism provides an intuitive picture of the resonances in the coupled
channel approach, as bound states of one bound channel, which decays into open
ones. It also provides an insight and practical rules for evaluating couplings
of the resonances to external sources and how to deal with final state
interaction in production processes. As an application of the formalism we
evaluate the wave functions of the two $\Lambda(1405)$ states in the $\pi
\Sigma$, $\bar{K} N$ and other coupled channels.",1007.3923v2
2016-05-16,The arithmetic geometry of resonant Rossby wave triads,"Linear wave solutions to the Charney-Hasegawa-Mima partial differential
equation with periodic boundary conditions have two physical interpretations:
Rossby (atmospheric) waves, and drift (plasma) waves in a tokamak. These waves
display resonance in triads. In the case of infinite Rossby deformation radius,
the set of resonant triads may be described as the set of integer solutions to
a particular homogeneous Diophantine equation, or as the set of rational points
on a projective surface. We give a rational parametrization of the smooth
points on this surface, answering the question: What are all resonant triads?
We also give a fiberwise description, yielding a procedure to answer the
question: For fixed $r \in \mathbb{Q}$, what are all wavevectors $(x,y)$ that
resonate with a wavevector $(a,b)$ with $a/b = r$?",1605.04637v3
2018-06-08,Coupled-Mode Theory for Stationary and Nonstationary Resonant Sound Propagation,"We present a complete analytical derivation of the equations used for
stationary and nonstationary wave systems regarding resonant sound transmission
and reflection described by the phenomenological Coupled-Mode Theory. We
calculate the propagating and coupling parameters used in Coupled-Mode Theory
directly by utilizing the generalized eigenwave-eigenvalue problem from the
Hamiltonian of the sound wave equations. This Hamiltonian formalization can be
very useful since it has the ability to describe mathematically a broad range
of acoustic wave phenomena. We demonstrate how to use this theory as a basis
for perturbative analysis of more complex resonant scattering scenarios. In
particular, we also form the effective Hamiltonian and coupled-mode parameters
for the study of sound resonators with background moving media. Finally, we
provide a comparison between Coupled-Mode theory and full-wave numerical
examples, which validate the Hamiltonian approach as a relevant model to
compute the scattering characteristics of waves by complex resonant systems.",1806.02971v1
2018-06-29,Optical probing of Rayleigh wave driven magneto-acoustic resonance,"The resonant interaction of electrically excited travelling surface acoustic
waves and magnetization has been hitherto probed through the acoustic
component. In this work it is investigated using time-resolved magneto-optical
detection of magnetization dynamics. To that end, we develop an experimental
scheme where laser pulses are used both to generate the acoustic wave frequency
and to probe magnetization dynamics thus ensuring perfect phase locking. The
light polarization dependence of the signal enables to disentangle elasto-optic
and magneto-optic contributions and to obtain the in-plane and out-of-plane
dynamic magnetization components. Magnetization precession is proved to be
driven solely by the acoustic wave. Its amplitude is shown to resonate at the
same field at which we detect piezo-electrically the resonant attenuation of
the acoustic wave, clearly evidencing the magneto-acoustic resonance with high
sensitivity.",1806.11410v1
2022-11-28,Energetic electron precipitation driven by electromagnetic ion cyclotron waves from ELFIN's low altitude perspective,"We review comprehensive observations of electromagnetic ion cyclotron (EMIC)
wave-driven energetic electron precipitation using data from the energetic
electron detector on the Electron Losses and Fields InvestigatioN (ELFIN)
mission, two polar-orbiting low-altitude spinning CubeSats, measuring 50-5000
keV electrons with good pitch-angle and energy resolution. EMIC wave-driven
precipitation exhibits a distinct signature in energy-spectrograms of the
precipitating-to-trapped flux ratio: peaks at 0.5 MeV which are abrupt (bursty)
with significant substructure (occasionally down to sub-second timescale).
Multiple ELFIN passes over the same MLT sector allow us to study the spatial
and temporal evolution of the EMIC wave - electron interaction region. Using
two years of ELFIN data, we assemble a statistical database of 50 events of
strong EMIC wave-driven precipitation. Most reside at L=5-7 at dusk, while a
smaller subset exists at L=8-12 at post-midnight. The energies of the
peak-precipitation ratio and of the half-peak precipitation ratio (our proxy
for the minimum resonance energy) exhibit an L-shell dependence in good
agreement with theoretical estimates based on prior statistical observations of
EMIC wave power spectra. The precipitation ratio's spectral shape for the most
intense events has an exponential falloff away from the peak (i.e., on either
side of 1.45 MeV). It too agrees well with quasi-linear diffusion theory based
on prior statistics of wave spectra. Sub-MeV electron precipitation observed
concurrently with strong EMIC wave-driven 1MeV precipitation has a spectral
shape that is consistent with efficient pitch-angle scattering down to 200-300
keV by much less intense higher frequency EMIC waves. These results confirm the
critical role of EMIC waves in driving relativistic electron losses. Nonlinear
effects may abound and require further investigation.",2211.15653v1
1997-10-09,Alternating-Spin Ladders,"We investigate a two-leg spin ladder system composed of alternating-spin
chains with two-different kind of spins. The fixed point properties are
discussed by using spin-wave analysis and non-linear sigma model techniques.
The model contains various massive phases, reflecting the interplay between the
bond-alternation and the spin-alternation.",9710082v1
2009-02-28,Nanostratification of optical excitation in self-interacting 1D arrays,"The major assumption of the Lorentz-Lorenz theory about uniformity of local
fields and atomic polarization in dense material does not hold in finite groups
of atoms, as we reported earlier [A. E. Kaplan and S. N. Volkov, Phys. Rev.
Lett., v. 101, 133902 (2008)]. The uniformity is broken at sub-wavelength
scale, where the system may exhibit strong stratification of local field and
dipole polarization, with the strata period being much shorter than the
incident wavelength. In this paper, we further develop and advance that theory
for the most fundamental case of one-dimensional arrays, and study nanoscale
excitation of so called ""locsitons"" and their standing waves (strata) that
result in size-related resonances and related large field enhancement in finite
arrays of atoms. The locsitons may have a whole spectrum of spatial
frequencies, ranging from long waves, to an extent reminiscent of ferromagnetic
domains, -- to super-short waves, with neighboring atoms alternating their
polarizations, which are reminiscent of antiferromagnetic spin patterns. Of
great interest is the new kind of ""hybrid"" modes of excitation, greatly
departing from any magnetic analogies. We also study differences between
Ising-like near-neighbor approximation and the case where each atom interacts
with all other atoms in the array. We find an infinite number of ""exponential
eigenmodes"" in the lossless system in the latter case. At certain ""magic""
numbers of atoms in the array, the system may exhibit self-induced (but linear
in the field) cancellation of resonant local-field suppression. We also studied
nonlinear modes of locsitons and found optical bistability and hysteresis in an
infinite array for the simplest modes.",0903.0045v2
2011-12-14,Gravitational Waves from Quasicircular Extreme Mass-Ratio Inspirals as Probes of Scalar-Tensor Theories,"A stellar-mass compact object spiraling into a supermassive black hole, an
extreme-mass-ratio inspiral (EMRI), is one of the targets of future
gravitational-wave detectors and it offers a unique opportunity to test General
Relativity (GR) in the strong-field. We study whether generic scalar-tensor
(ST) theories can be further constrained with EMRIs. We show that in the EMRI
limit, all such theories universally reduce to massive or massless Brans-Dicke
theory and that black holes do not emit dipolar radiation to all orders in
post-Newtonian (PN) theory. For massless theories, we calculate the scalar
energy flux in the Teukolsky formalism to all orders in PN theory and fit it to
a high-order PN expansion. We derive the PN ST corrections to the Fourier
transform of the gravitational wave response and map it to the parameterized
post-Einsteinian framework. We use the effective-one-body framework adapted to
EMRIs to calculate the ST modifications to the gravitational waveform. We find
that such corrections are smaller than those induced in the early inspiral of
comparable-mass binaries, leading to projected bounds on the coupling that are
worse than current Solar System ones. Brans-Dicke theory modifies the
weak-field, with deviations in the energy flux that are largest at small
velocities. For massive theories, superradiance can lead to resonances in the
scalar energy flux that can lead to floating orbits outside the innermost
stable circular orbit and that last until the supermassive black hole loses
enough mass and spin-angular momentum. If such floating orbits occur in the
frequency band of LISA, they would lead to a large dephasing (~1e6 rads),
preventing detection with GR templates. A detection that is consistent with GR
would then rule out floating resonances at frequencies lower than the lowest
observed frequency, allowing for the strongest constraints yet on massive ST
theories.",1112.3351v2
2023-01-27,Geodesics and gravitational waves in chaotic extreme-mass-ratio inspirals: the curious case of Zipoy-Voorhees black-hole mimickers,"Due to the growing capacity of gravitational-wave astronomy and black-hole
imaging, we will soon be able to emphatically decide if astrophysical objects
lurking in galactic centers are black holes. Sgr A*, one of the most prolific
astronomical radio sources in our galaxy, is the focal point for tests of
general relativity. Current mass and spin constraints predict that the central
object of the Milky Way is supermassive and slowly rotating, thus can be
conservatively modeled as a Schwarzschild black hole. The well-established
presence of accretion disks and astrophysical environments around supermassive
objects can deform their geometry and complicate their observational scientific
yield. Here, we study extreme-mass-ratio binaries comprised of a minuscule
secondary object inspiraling onto a supermassive Zipoy-Voorhees compact object;
the simplest exact solution of general relativity that describes a static,
spheroidal deformation of Schwarzschild spacetime. We examine geodesics of
prolate and oblate deformations for generic orbits and reevaluate the
non-integrability of Zipoy-Voorhees spacetime through the existence of resonant
islands in the orbital phase space. By including radiation loss with
post-Newtonian techniques, we evolve stellar-mass secondary objects around a
supermassive Zipoy-Voorhees primary and find clear imprints of
non-integrability in these systems. The peculiar structure of the primary,
allows for, not only typical single crossings of transient resonant islands,
that are well-known for non-Kerr objects, but also inspirals that traverse
through several islands, in a brief period of time, that lead to multiple
glitches in the gravitational-wave frequency evolution of the binary. The
detectability of glitches with future spaceborne detectors can, therefore,
narrow down the parameter space of exotic solutions that, otherwise, can cast
identical shadows with black holes.",2301.11483v2
2023-05-20,Frequency-tunable magnetic field sensing using continuous-wave optically detected magnetic resonance with nitrogen-vacancy centers in diamond,"The nitrogen-vacancy (NV) center is a promising candidate to realize
practical quantum sensors with high sensitivity and high spatial resolution,
even at room temperature and atmospheric pressure. In conventional
high-frequency AC magnetometry with NV centers, the setup requires a pulse
sequence with an appropriate time synchronization and strong microwave power.
To avoid these practical difficulties, AC magnetic field sensing using
continuous-wave opticallydetected magnetic resonance (CW-ODMR) was recently
demonstrated. That previous study utilized radio frequency (RF) dressed states
generated by the coherent interaction between the electron spin of the NV
center and the RF wave. However, the drawback of this method is that the
detectable frequency of the AC magnetic fields is fixed. Here, we propose and
demonstrate frequency-tunable magnetic field sensing based on CW-ODMR. In the
new sensing scheme, we obtain RF double-dressed states by irradiation with a RF
field at two different frequencies. One creates the RF dressed states and
changes the frequency of the target AC field. The other is a target AC field
that induces a change in the CW-ODMR spectrum by generating the RF
double-dressed states through coherent interaction with the RF dressed states.
The sensitivity of our method is estimated to be comparable to or even higher
than that of the conventional method based on a RF field with a single
frequency. The estimated bandwidth is 7.45 MHz, higher than that of the
conventional method using the RF dressed states. Our frequency-tunable magnetic
field sensor based on CW-ODMR paves the way for new applications in diamond
devices.",2305.12141v1
2017-02-03,Enhanced Spin Conductance of a Thin-Film Insulating Antiferromagnet,"We investigate spin transport by thermally excited spin waves in an
antiferromagnetic insulator. Starting from a stochastic Landau-Lifshitz-Gilbert
phenomenology, we obtain the out-of-equilibrium spin-wave properties. In linear
response to spin biasing and a temperature gradient, we compute the spin
transport through a normal metal$|$antiferromagnet$|$normal metal
heterostructure. We show that the spin conductance diverges as one approaches
the spin-flop transition; this enhancement of the conductance should be readily
observable by sweeping the magnetic field across the spin-flop transition. The
results from such experiments may, on the one hand, enhance our understanding
of spin transport near a phase transition, and on the other be useful for
applications that require a large degree of tunability of spin currents. In
contrast, the spin Seebeck coefficient does not diverge at the spin-flop
transition. Furthermore, the spin Seebeck coefficient is finite even at zero
magnetic field, provided that the normal metal contacts break the symmetry
between the antiferromagnetic sublattices.",1702.00975v2
2020-11-06,Acoustic spin Hall effect in strong spin-orbit metals,"We report on the observation of the acoustic spin Hall effect that
facilitates lattice motion induced spin current via spin orbit interaction
(SOI). Under excitation of surface acoustic wave (SAW), we find a spin current
flows orthogonal to the propagation direction of a surface acoustic wave (SAW)
in non-magnetic metals. The acoustic spin Hall effect manifests itself in a
field-dependent acoustic voltage in non-magnetic metal (NM)/ferromagnetic metal
(FM) bilayers. The acoustic voltage takes a maximum when the NM layer thickness
is close to its spin diffusion length, vanishes for NM layers with weak SOI and
increases linearly with the SAW frequency. To account for these results, we
find the spin current must scale with the SOI and the time derivative of the
lattice displacement. Such form of spin current can be derived from a Berry
electric field associated with time varying Berry curvature and/or an
unconventional spin-lattice interaction mediated by SOI. These results, which
imply the strong coupling of electron spins with rotating lattices via the SOI,
show the potential of lattice dynamics to supply spin current in strong spin
orbit metals.",2011.03246v2
2000-08-17,Atomic four-wave mixing: fermions versus bosons,"We compare the efficiency of four-wave mixing in quantum degenerate gases of
bosonic and fermionic atoms. It is shown that matter-wave gratings formed from
either bosonic or fermionic atoms can in principle exhibit nearly identical
Bragg-scattering, i.e. four-wave mixing, properties. This implies that effects
such as coherent matter-wave amplification and superradiance can occur in
degenerate fermi gases. While in the boson case the Bragg resonance is clearly
due to `Bose enhancement', in the case of fermions the resonance is due to
constructive many-particle quantum interference.",0008264v1
2013-04-16,Rogue waves emerging from the resonant interaction of three waves,"We introduce a novel family of analytic solutions of the three-wave resonant
interaction equations to the purpose of modeling unique events, i.e. ""amplitude
peaks"" which are isolated in space and time. The description of these solutions
is likely to be a crucial step in the understanding and forecasting of
rogue-waves in a variety of multi-component wave dynamics, from oceanography to
optics, from plasma physics to acoustics.",1304.4402v1
2014-09-04,Elliptic Waves in Two Component Long Wave--Short Wave Resonance Interaction System in One and Two dimensions,"We consider (2+1) and (1+1) dimensional long-wave short-wave resonance
interaction systems. We construct an extensive set of exact periodic solutions
of these systems in terms of Lam\'e polynomials of order one and two. The
periodic solutions are classified into three categories as similar, mixed,
superposed elliptic solutions. We also discuss the hyperbolic solutions as
limiting cases.",1409.1328v1
2018-09-20,Explosive instability due to flow over a rippled bottom,"In this paper, we study Bragg resonance, i.e. the triad interaction between
surface and/or interfacial waves with bottom ripple, in presence of background
velocity. We show that when one of the constituent waves of the triad has
negative energy, the amplitudes of all the waves grow exponentially. This is
very different from classic Bragg resonance in which one wave decays to cause
growth of the other. The instabilities we observe are `explosive', and are
different from normal mode shear instabilities since our velocity profiles are
linearly stable. Our work may explain the existence of large amplitude internal
waves over periodic bottom ripples in presence of tidal flow observed in oceans
and estuaries.",1809.07507v1
2020-06-04,Cylindrical gravitational waves: radiation and resonance,"In the weak field approximation the gravitational wave is approximated as a
linear wave, which ignores the nonlinear effect. In this paper, we present an
exact general solution of the cylindrical gravitational wave. The exact
solution of the cylindrical gravitational wave is far different from the weak
field approximation. This solution implies the following conclusions. (1) There
exist gravitational monopole radiations in the cylindrical gravitational
radiation. (2) The gravitational radiation may generate the resonance in the
spacetime. (3) The nonlinearity of the gravity source vanishes after time
averaging, so the observed result of a long-time measurement may be linear.",2006.06405v1
1999-01-14,Spin dynamics in the generalized ferromagnetic Kondo model for manganites,"Dynamical spin susceptibility is calculated for the generalized ferromagnetic
Kondo model which describes itinerant $e_{g}$ electrons interacting with
localized $t_{2g}$ electrons with antiferromagnetic coupling. The calculations
done in the mean field approximation show that the spin-wave spectrum of the
system in ferromagnetic state has two branches, acoustic and optic ones.
Self-energy corrections to the spectrum are considered and the acoustic
spin-wave damping is evaluated.",9901141v1
2001-08-23,Filtering spin with tunnel-coupled electron wave guides,"We show how momentum-resolved tunneling between parallel electron wave guides
can be used to observe and exploit lifting of spin degeneracy due to Rashba
spin-orbit coupling. A device is proposed that achieves spin filtering without
using ferromagnets or the Zeeman effect.",0108373v2
2018-04-02,Pulsars as Weber gravitational wave detectors,"A gravitational wave passing through a pulsar will lead to a variation in the
moment of inertia of the pulsar affecting its rotation. This will affect the
extremely accurately measured spin rate of the pulsar as well as its pulse
profile (due to induced wobbling depending on the source direction). The effect
will be most pronounced at resonance and should be detectable by accurate
observations of the pulsar signal. The pulsar, in this sense, acts as a
remotely stationed Weber detector of gravitational waves whose signal can be
monitored on earth. With possible gravitational wave sources spread around in
the universe, pulsars in their neighborhoods can provide us a family of
\textit{remote} detectors all of which can be monitored on earth. Even if GW
are detected directly by earth based conventional detectors, such pulsar
detectors can provide additional information for accurate determination of the
source location. This can be of crucial importance for sources which do not
emit any other form of radiation such as black hole mergers. For the
gravitational wave events already detected by LIGO (and Virgo), our proposal
suggests that one should look for specific pulsars which would have been
disturbed by these events, and will transmit this disturbance via their pulse
signals in any foreseeable future. If these future pulsar events can be
predicted with accuracy then a focused effort can be made to detect any
possible changes in the signals of those specific pulsars.",1804.00453v2
2000-07-04,Spin-wave spectrum of a two-dimensional itinerant electron system: Analytic results for the incommensurate spiral phase in the strong-coupling limit,"We study the zero-temperature spin fluctuations of a two-dimensional
itinerant-electron system with an incommensurate magnetic ground state
described by a single-band Hubbard Hamiltonian. We introduce the
(broken-symmetry) magnetic phase at the mean-field (Hartree-Fock) level through
a \emph{spiral spin configuration} with characteristic wave vector
$\gmathbf{Q}$ different in general from the antiferromagnetic wave vector
$\gmathbf{Q_{AF}}$, and consider spin fluctuations over and above it within the
electronic random-phase (RPA) approximation. We obtain a \emph{closed} system
of equations for the generalized wave vector and frequency dependent
susceptibilities, which are equivalent to the ones reported recently by Brenig.
We obtain, in addition, analytic results for the spin-wave dispersion relation
in the strong-coupling limit of the Hubbard Hamiltonian and find that at finite
doping the spin-wave dispersion relation has a \emph{hybrid form} between that
associated with the (localized) Heisenberg model and that associated with the
(long-range) RKKY exchange interaction. We also find an instability of the
spin-wave spectrum in a finite region about the center of the Brillouin zone,
which signals a physical instability toward a different spin- or, possibly,
charge-ordered phase, as, for example, the stripe structures observed in the
high-Tc materials. We expect, however, on physical grounds that for wave
vectors external to this region the spin-wave spectrum that we have determined
should survive consideration of more sophisticated mean-field solutions.",0007044v1
2014-10-14,Spin precession mapping at ferromagnetic resonance via nuclear resonant scattering,"We probe the spin dynamics in a thin magnetic film at ferromagnetic resonance
by nuclear resonant scattering of synchrotron radiation at the 14.4 keV
resonance of $^{57}$Fe. The precession of the magnetization leads to an
apparent reduction of the magnetic hyperfine field acting at the $^{57}$Fe
nuclei. The spin dynamics is described in a stochastic relaxation model adapted
to the ferromagnetic resonance theory by Smit and Beljers to model the decay of
the excited nuclear state. From the fits of the measured data the shape of the
precession cone of the spins is determined. Our results open a new perspective
to determine magnetization dynamics in layered structures with very high depth
resolution by employing ultrathin isotopic probe layers.",1410.3689v1
2016-12-21,Superconducting grid-bus surface code architecture for hole-spin qubits,"We present a scalable hybrid architecture for the 2D surface code combining
superconducting resonators and hole-spin qubits in nanowires with tunable
direct Rashba spin-orbit coupling. The back-bone of this architecture is a
square lattice of capacitively coupled coplanar waveguide resonators each of
which hosts a nanowire hole-spin qubit. Both the frequency of the qubits and
their coupling to the microwave field are tunable by a static electric field
applied via the resonator center pin. In the dispersive regime, an entangling
two-qubit gate can be realized via a third order process, whereby a virtual
photon in one resonator is created by a first qubit, coherently transferred to
a neighboring resonator, and absorbed by a second qubit in that resonator.
Numerical simulations with state-of-the-art coherence times yield gate
fidelities approaching the $99\%$ fault tolerance threshold.",1612.07292v1
2024-04-16,A broadband vortex beam generation by reflective meta-surface based on metal double-slit resonant ring,"Recently, meta-surface(MS) has emerged as a promising alternative method for
generating vortex waves. At the same time, MS also face the problem of narrow
bandwidth, in order to obtain a board bandwidth, the MS unit cells structure
become more and more complex, which will deduce many inconveniences to the
preparation process of MS device. Therefore, we want to design a simple MS unit
cell with a multi-frequency selection. In this paper, based on the principle of
geometric phase, we design a simple reflective MS unit cell based on metal
double-slit resonant ring. We elaborate on the resonance mechanism of the MS
unit cell. Under the normal incidence of circularly polarized (CP) waves, the
reflection coefficient of the same polarization was greater than 85%. By
rotating the orientation angle of the resonator on the MS unit cell, the
continuous 2pi phase coverage was satisfied in the frequency range of
0.52THz-1.1THz, and the relative bandwidth becomes 71.6%. Based on this, we
construct a vortex generator by using a 15*15 MS unit array. The right-handed
circularly polarized waves (RCP) and left-handed circularly polarized waves
(LCP) are separately incident on MS with topological charges of l=1,2,3 under
multiple resonant frequencies. The generated RCP vortex wave with topological
charges of l=-1,-2,-3 and the generated LCP vortex wave with topological
charges of l=1,2,3. The numerical simulation results exhibit our designed MS
with multiple resonance outcomes can achieve a multi-broadband operation and
generate a wide-band vortex beam. In addition, we also calculate the pattern
purity. Through theoretical analysis and numerical simulation, we prove that
our designed MS can generate a broadband vortex wave.",2404.10330v1
2010-12-21,Non-Volatile Magnonic Logic Circuits Engineering,"We propose a concept of magnetic logic circuits engineering, which takes an
advantage of magnetization as a computational state variable and exploits spin
waves for information transmission. The circuits consist of magneto-electric
cells connected via spin wave buses. We present the result of numerical
modeling showing the magneto-electric cell switching as a function of the
amplitude as well as the phase of the spin wave. The phase-dependent switching
makes it possible to engineer logic gates by exploiting spin wave buses as
passive logic elements providing a certain phase-shift to the propagating spin
waves. We present a library of logic gates consisting of magneto-electric cells
and spin wave buses providing 0 or p phase shifts. The utilization of phases in
addition to amplitudes is a powerful tool which let us construct logic circuits
with a fewer number of elements than required for CMOS technology. As an
example, we present the design of the magnonic Full Adder Circuit comprising
only 5 magneto-electric cells. The proposed concept may provide a route to more
functional wave-based logic circuitry with capabilities far beyond the limits
of the traditional transistor-based approach.",1012.4768v1
2010-12-25,Interaction of a nonlinear spin wave and magnetic soliton in a uniaxial anisotropic ferromagnet,"We study the interaction of a nonlinear spin-wave and magnetic soliton in a
uniaxial anisotropic ferromagnet. By means of a reasonable assumption and a
straightforward Darboux transformation one- and two-soliton solutions in a
nonlinear spin-wave background are obtained analytically, and their properties
are discussed in detail. In the background of a nonlinear spin wave the
amplitude of the envelope soliton has the spatial and temporal period, and
soliton can be trapped only in space. The amplitude and wave number of spin
wave have the different contribution to the width, velocity, and the amplitude
of soliton solutions, respectively. The envelope of solution hold the shape of
soliton, and the amplitude of each envelope soliton keeps invariability before
and after collision which shows the elastic collision of two envelope soliton
in the background of a nonlinear spin wave.",1012.5467v1
2015-09-16,Microwave excitation of spin wave beams in thin ferromagnetic films,"We present an approach enabling generation of narrow spin wave beams in thin
homogeneous ferromagnetic films. The main idea is to match the wave vector of
the spin wave with that corresponding to the spectral maximum of the exciting
microwave magnetic field only locally, in the region of space from which the
beam should be launched. We show that this can be achieved with the aid of a
properly designed coplanar waveguide transducer generating a nonuniform
microwave magnetic field. The resulting two-dimensional spin wave beams
obtained in micromagnetic simulations propagate over distances of several
micrometers. The proposed approach requires neither inhomogeneity of the
ferromagnetic film nor nonuniformity of the biasing magnetic field, and it can
be generalized to yield multiple spin wave beams of different width at the same
frequency. Other possible excitation scenarios and applications of spin wave
beam magnonics are also discussed.",1509.05061v2
2018-03-13,Spin wave localization and guiding by magnon band structure engineering in yttrium iron garnet,"In spintronics the propagation of spin-wave excitations in magnetically
ordered materials can also be used to transport and process information. One of
the most popular materials in this regard is the ferrimagnetic insulator
yttrium-iron-garnet due its exceptionally small spin-wave damping parameter.
While the small relaxation rate allows for large propagation length of magnetic
excitations, it also leads to non-locality of the magnetic properties. By
imaging spin waves their band structure is mapped. In doing so wave vector
selection is shown to suppress dispersion effects to a large extent allowing
for local measurements of spin relaxation. Moreover we demonstrate even higher
control of magnon propagation by employing the wave vector selectivity near an
avoided crossing of different spin-wave modes where the group velocity
approaches zero. Here local engineering of the dispersion allows constructing
magnonic waveguides and at the same time reveals the local relaxation
properties.",1803.04943v3
2020-01-24,Propagating magnetic droplet solitons as moveable nanoscale spin-wave sources with tunable direction of emission,"Magnetic droplets are strongly nonlinear and localized spin-wave solitons
that can be formed in current-driven nanocontacts. Here, we propose a simple
way to launch droplets in an inhomogeneous nanoscopic waveguide. We use the
drift motion of a droplet and show that in a system with broken translational
symmetry, the droplet acquires a linear momentum and propagates. We find that
the droplet velocity can be tuned via the strength of the break in symmetry and
the size of the nanocontact. In addition, we demonstrate that the launched
droplet can propagate up to several micrometers in a realistic system with
reasonable damping. Finally, we demonstrate how an annihilating droplet
delivers its momentum to a highly nonreciprocal spin-wave burst with a tunable
wave vector with nanometer wavelengths. Such a propagating droplet can be used
as a moveable spin-wave source in nanoscale magnonic networks. The presented
method enables full control of the spin-wave emission direction, which can
largely extend the freedom to design integrated magnonic circuits with a single
spin-wave source.",2001.08967v1
2020-01-30,An anomalous refraction of spin waves as a way to guide signals in curved magnonic multimode waveguides,"We present a method for efficient spin wave guiding within the magnonic
nanostructures. Our technique is based on the anomalous refraction in the
metamaterial flat slab. The gradual change of the material parameters
(saturation magnetization or magnetic anisotropy) across the slab allows
tilting the wavefronts of the transmitted spin waves and controlling the
refraction. Numerical studies of the spin wave refraction are preceded by the
analytical calculations of the phase shift acquired by the spin wave due to the
change of material parameters in a confined area. We demonstrate that our
findings can be used to guide the spin waves smoothly in curved waveguides,
even through sharp bends, without reflection and scattering between different
waveguide's modes, preserving the phase -- the quantity essential for wave
computing.",2001.11356v1
2020-02-14,Spin-wave diode and circulator based on unidirectional coupling,"In magnonics, an emerging branch of wave physics characterized by low-energy
consumption, it is highly desirable to realize circuit elements within the
scope of spin-wave computing. Here, based on numerical simulations, we
demonstrate the functionality of the spin-wave diode and the circulator to
steer and manipulate spin waves over a wide range of frequency in the GHz
regime. They take advantage of the unidirectional coupling induced by the
interfacial Dzyaloshinskii-Moriya interaction to transfer the spin wave between
thin ferromagnetic layers in only one direction of propagation. Using the
multilayered structure consisting of Py and Co in direct contact with Pt, we
obtain sub-micrometer-size devices of high efficiency. In the diode, the power
loss ratio between forward and reverse direction reaches 22 dB, while in the
four-port circulator, the efficiency exceeds 13 dB. Thus, our work contributes
to the emerging branch of energy-efficient magnonic logic devices, where,
thanks to short wavelength of spin waves, it is possible to realize nanoscale
devices.",2002.06096v1
2020-07-23,Density Wave Mediated Dzyaloshinskii-Moriya Interactions,"We investigate the effect that density wave states have on the localized
spins of a square lattice. We find that topologically nontrivial density wave
states can induce stable Dzyaloshinskii-Moriya (DM) interactions among the
localized spins of the lattice in the presence of an external magnetic field,
and we study the resulting spin models for both antiferromagnetic and
ferromagnetic backgrounds. While the density wave state itself can contribute
to the the thermal Hall effect, as shown by Li & Lee (arXiv:1905.04248v3),
symmetry considerations preclude the resulting spin excitations from inducing a
further thermal Hall effect. We utilize a Holstein-Primakoff (HP) substitution
about the classical mean-field ground state to calculate the magnon dispersion
for LSCO and find that the density wave induces a weak $d_{x^2-y^2}$
anisotropy; upon calculating the non-Abelian Berry curvature for this magnon
branch we show explicitly that the magnon contribution to $\kappa_{xy}$ is
zero. Finally, we calculate corrections to the magnetic ground state energy,
spin canting angles, and the spin-wave dispersion due to the topological
density wave for ferromagnetic backgrounds. We find that terms linear in the HP
bosons can affect the critical behavior, a point previously overlooked in the
literature.",2007.11719v1
2023-07-19,Checkerboard bubble lattice formed by octuple-period quadruple-$Q$ spin density waves,"We investigate multiple-$Q$ instability on a square lattice at particular
ordering wave vectors. We find that a superposition of quadruple-$Q$ spin
density waves, which are connected by fourfold rotational and mirror
symmetries, gives rise to a checkerboard bubble lattice with a collinear spin
texture as a result of the geometry among the constituent ordering wave vectors
in the Brillouin zone. By performing the simulated annealing for a fundamental
spin model, we show that such a checkerboard bubble lattice is stabilized under
an infinitesimally small easy-axis two-spin anisotropic interaction and
biquadratic interaction at zero field, while it is degenerate with an
anisotropic double-$Q$ state in the absence of the biquadratic interaction. The
obtained multiple-$Q$ structures have no intensities at high-harmonic wave
vectors in contrast to other multiple-$Q$ states, such as a magnetic skyrmion
lattice. We also show that the checkerboard bubble lattice accompanies the
charge density wave and exhibits a nearly flat band dispersion in the
electronic structure. Our results provide another route to realize exotic
multiple-$Q$ spin textures by focusing on the geometry and symmetry in terms of
the wave vectors in momentum space.",2307.10444v1
2019-10-07,Chiral spin-wave velocities induced by all-garnet interfacial Dzyaloshinskii-Moriya interaction in ultrathin yttrium iron garnet films,"Spin waves can probe the Dzyaloshinskii-Moriya interaction (DMI) which gives
rise to topological spin textures, such as skyrmions. However, the DMI has not
yet been reported in yttrium iron garnet (YIG) with arguably the lowest damping
for spin waves. In this work, we experimentally evidence the interfacial DMI in
a 7~nm-thick YIG film by measuring the nonreciprocal spin wave propagation in
terms of frequency, amplitude and most importantly group velocities using all
electrical spin-wave spectroscopy. The velocities of propagating spin waves
show chirality among three vectors, i.e. the film normal direction, applied
field and spin-wave wavevector. By measuring the asymmetric group velocities,
we extract a DMI constant of 16~$\mu$J/m$^{2}$ which we independently confirm
by Brillouin light scattering. Thickness-dependent measurements reveal that the
DMI originates from the oxide interface between the YIG and garnet substrate.
The interfacial DMI discovered in the ultrathin YIG films is of key importance
for functional chiral magnonics as ultra-low spin-wave damping can be achieved.",1910.02599v2
2023-03-08,True amplification of spin waves in magnonic nano-waveguides,"Magnonic nano-devices exploit magnons -- quanta of spin waves -- to transmit
and process information within a single integrated platform that has the
potential to outperform traditional semiconductor-based electronics for low
power applications. The main missing cornerstone of this information
nanotechnology is an efficient scheme for the direct amplification of
propagating spin waves. The recent discovery of spin-orbit torque provided an
elegant mechanism for propagation losses compensation. While partial
compensation of the spin-wave damping has allowed for spin-wave signal
modulation, true amplification - the exponential increase in the spin-wave
intensity during propagation - has so far remained elusive. Here we evidence
the operating conditions to achieve unambiguous amplification using clocked
nanoseconds-long spin-orbit torque pulses in sub-micrometer wide magnonic
waveguides, where the effective magnetization has been engineered to be close
to zero to suppress the detrimental magnon-magnon scattering. As a result, we
achieve an exponential increase in the intensity of propagating spin waves up
to 500 % at a propagation distance of several micrometers. These results pave
the way towards the implementation of energy efficient, cascadable magnonic
architectures for wave-based information processing and complex on-chip
computation.",2303.04695v2
2017-12-11,Two-photon driven Kerr resonator for quantum annealing with three-dimensional circuit QED,"We propose a realizable circuit QED architecture for engineering states of a
superconducting resonator off-resonantly coupled to an ancillary
superconducting qubit. The qubit-resonator dispersive interaction together with
a microwave drive applied to the qubit gives rise to a Kerr resonator with
two-photon driving that enables us to efficiently engineer the quantum state of
the resonator such as generation of the Schrodinger cat states for
resonator-based universal quantum computation. Moreover, the presented
architecture is easily scalable for solving optimization problem mapped into
the Ising spin glass model, and thus served as a platform for quantum
annealing. Although various scalable architecture with superconducting qubits
have been proposed for realizing quantum annealer, the existing annealers are
currently limited to the coherent time of the qubits. Here, based on the
protocol for realizing two-photon driven Kerr resonator in three-dimensional
circuit QED (3D cQED), we propose a flexible and scalable hardware for
implementing quantum annealer that combines the advantage of the long coherence
times attainable in 3D cQED and the recently proposed resonator based
Lechner-Hauke-Zoller (LHZ) scheme. In the proposed resonator based LHZ
annealer, each spin is encoded in the subspace formed by two coherent state of
3D microwave superconducting resonator with opposite phase, and thus the
fully-connected Ising model is mapped onto the network of the resonator with
local tunable three-resonator interaction. This hardware architecture provides
a promising physical platform for realizing quantum annealer with improved
coherence.",1712.03613v2
2012-02-05,Topological and Entanglement Properties of Resonating Valence Bond wavefunctions,"We examine in details the connections between topological and entanglement
properties of short-range resonating valence bond (RVB) wave functions using
Projected Entangled Pair States (PEPS) on kagome and square lattices on
(quasi-)infinite cylinders with generalized boundary conditions (and perimeters
with up to 20 lattice spacings). Making use of disconnected topological sectors
in the space of dimer lattice coverings, we explicitly derive (orthogonal)
""minimally entangled"" PEPS RVB states. For the kagome lattice, we obtain, using
the quantum Heisenberg antiferromagnet as a reference model, the finite size
scaling of the energy separations between these states. In particular, we
extract two separate (vanishing) energy scales corresponding (i) to insert a
vison line between the two ends of the cylinder and (ii) to pull out and freeze
a spin at either end. We also investigate the relations between bulk and
boundary properties and show that, for a bipartition of the cylinder, the
boundary Hamiltonian defined on the edge can be written as a product of a
highly non-local projector with an emergent (local) su(2)-invariant
one-dimensional (superfluid) t--J Hamiltonian, which arises due to the symmetry
properties of the auxiliary spins at the edge. This multiplicative structure, a
consequence of the disconnected topological sectors in the space of dimer
lattice coverings, is characteristic of the topological nature of the states.
For minimally entangled RVB states, it is shown that the entanglement spectrum,
which reflects the properties of the edge modes, is a subset (half for kagome
RVB) of the spectrum of the local Hamiltonian, providing e.g. a simple argument
on the origin of the topological entanglement entropy S0=-ln 2 of Z2 spin
liquids. We propose to use these features to probe topological phases in
microscopic Hamiltonians and some results are compared to existing DMRG data.",1202.0947v4
2017-07-10,Controlling surface charge and spin density oscillations by Dirac plasmon interaction in thin topological insulators,"We study the selective excitation at infrared and THz frequencies of optical
and acoustic plasmonic modes supported by thin topological insulators. These
modes are characterized by effective net charge or net spin density,
respectively, and we study their excitation by combining many-body and
electromagnetic calculations. We first show that non-locality can significantly
modify the plasmonic response: it changes the energy of propagating plasmons up
to tens of percent. We then discuss how, by changing the distance between a
dipolar source and a semi-infinite 10 nm thin film, it is possible to control
the excitation of acoustic and optical propagating plasmons, which can
propagate over a distance of several plasmonic wavelengths. Furthermore, we
consider 10 nm thin TI nanodisks and study the excitation of acoustic and
optical localized plasmon modes by a point dipole source and plane wave
illumination, respectively. The resonant plasmonic modes appear at frequencies
that strongly depends on the size of the disk, and that can be potentially
tuned by applying electrostatic gating to modify the Fermi Energy of the
conductive 2-dimensional layer that forms at the interfaces of the TI. We
observe a spectral shift from ~29 $\mu$m to ~34 $\mu$m by changing the Fermi
Energy from 250meV to 350meV. Last, the electromagnetic energy of these
plasmonics modes can be confined to very small regions, of effective volume
~(120 nm)^3 for the smaller disk considered, much less than the free-space
wavelength cubed $\lambda$^3 ~(35000 nm)^3. The strong confinement is desirable
for achieving very efficient coupling with nearby systems. Our detailed study
thus shows that thin topological insulators are a promising system to control
both the spin and charge oscillations associated with the plasmonic resonances,
with possible applications to fast, compact and electrically-controlled
spintronics devices.",1707.03050v2
2015-06-24,Modulational Instability in the Whitham Equation with Surface Tension and Vorticity,"We study modulational stability and instability in the Whitham equation,
combining the dispersion relation of water waves and a nonlinearity of the
shallow water equations, and modified to permit the effects of surface tension
and constant vorticity. When the surface tension coefficient is large, we show
that a periodic traveling wave of sufficiently small amplitude is unstable to
long wavelength perturbations if the wave number is greater than a critical
value, and stable otherwise, similarly to the Benjamin-Feir instability of
gravity waves. In the case of weak surface tension, we find intervals of stable
and unstable wave numbers, whose boundaries are associated with the extremum of
the group velocity, the resonance between the first and second harmonics, the
resonance between long and short waves, and a resonance between dispersion and
the nonlinearity. For each constant vorticity we show that a periodic traveling
wave of sufficiently small amplitude is unstable if the wave number is greater
than a critical value, and stable otherwise. Moreover it can be made stable for
a sufficiently large vorticity. The results agree with those based upon
numerical computations or formal multiple-scale expansions for the physical
problem.",1506.07560v2
2021-09-30,Reflection and transmission of a Kelvin-Helmholtz wave incident on a shock in a jet,"Screech tones in supersonic jets are underpinned by resonance between
downstream-travelling Kelvin-Helmholtz waves and upstream-travelling acoustic
waves. Specifically, recent work suggests that the relevant acoustic waves are
guided within the jet and are described by a discrete mode of the linearised
Navier-Stokes equations. However, the reflection mechanism that converts
downstream-travelling waves into upstream-travelling waves, and vice versa, has
not been thoroughly addressed, leading to missing physics within most resonance
models. In this work we investigate the reflection and transmission of waves
generated by the interaction between a Kelvin-Helmholtz wave and a normal shock
in an under-expanded jet using a mode-matching approach. Both vortex-sheet and
finite-thickness shear-layer models are explored, quantifying the impact of the
shear layer in the reflection process. This approach could enable more
quantitative predictions of resonance phenomena in jets and other fluid
systems.",2109.14988v1
2021-12-30,The dynamics and observability of circularly polarized kink waves,"Context. Kink waves are routinely observed in coronal loops. Resonant
absorption is a well-accepted mechanism that extracts energy from kink waves.
Nonlinear kink waves are know to be affected by the Kelvin-Helmholtz
instability. However, all previous numerical studies consider linearly
polarized kink waves. Aims. We study the properties of circularly polarized
kink waves on straight plasma cylinders, for both standing and propagating
waves, and compare them to the properties of linearly polarized kink waves.
Methods. We use the code MPI-AMRVAC to solve the full 3D Magnetohydrodynamic
(MHD) equations for a straight magnetic cylinder, excited by both standing and
propagating circularly polarized kink (m = 1) modes. Results. The damping due
to resonant absorption is independent of the polarization state. The morphology
or appearance of the induced resonant flow is different for the two
polarizations, however, there are essentially no differences in the
forward-modeled Doppler signals. For nonlinear oscillations, the growth rate of
small scales is determined by the total energy of the oscillation rather than
the perturbation amplitude. We discuss possible implications and seismological
relevance.",2112.14951v1
2023-04-12,Evidence of experimental three-wave resonant interactions between two dispersion branches,"We report the observation of nonlinear three-wave resonant interactions
between two different branches of the dispersion relation of hydrodynamic
waves, namely the gravity-capillary and sloshing modes. These atypical
interactions are investigated within a torus of fluid for which the sloshing
mode can be easily excited. A triadic resonance instability is then observed
due to this three-wave two-branch interaction mechanism. An exponential growth
of the instability and phase locking are evidenced. The efficiency of this
interaction is found to be maximal when the gravity-capillary phase velocity
matches the group velocity of the sloshing mode. For a stronger forcing,
additional waves are generated by a cascade of three-wave interactions
populating the wave spectrum. Such a three-wave two-branch interaction
mechanism is probably not restricted to hydrodynamics and could be of interest
in other systems involving several propagation modes.",2304.05668v1
2011-05-06,Decoherence-assisted initialization of a resident hole spin polarization in a two-dimensional hole gas,"We investigate spin dynamics of resident holes in a p-modulation-doped
GaAs/Al$_{0.3}$Ga$_{0.7}$As single quantum well. Time-resolved Faraday and Kerr
rotation, as well as resonant spin amplification, are utilized in our study. We
observe that nonresonant or high power optical pumping leads to a resident hole
spin polarization with opposite sign with respect to the optically oriented
carriers, while low power resonant optical pumping only leads to a resident
hole spin polarization if a sufficient in-plane magnetic field is applied. The
competition between two different processes of spin orientation strongly
modifies the shape of resonant spin amplification traces. Calculations of the
spin dynamics in the electron--hole system are in good agreement with the
experimental Kerr rotation and resonant spin amplification traces and allow us
to determine the hole spin polarization within the sample after optical
orientation, as well as to extract quantitative information about spin
dephasing processes at various stages of the evolution.",1105.1338v2
2008-02-26,Dynamical Structure Factor and Spin-Density Separation for a Weakly-Interacting Two-Component Bose Gas,"We show that spin-density separation in a Bose gas is not restricted to 1D
but also occurs in higher dimension. The ratio ($\alpha$) of the intra-species
atom-atom interaction strength to the inter-species interaction strength,
strongly influences the dynamics of spin-density separation and the elementary
excitations. The density wave is phonon-like for all values of $\alpha$. For
$\alpha<1$, spin wave is also phonon-like. The spin waves have a quadratic
dispersion in the $\alpha=1$ coupling regime, while in the phase separated
regime ($\alpha>1$) the spin waves are found to be damped. The dynamical
structure factor (DSF) reveals two distinct peaks corresponding to the density
and spin waves for $\alpha \le 1$. For $\alpha > 1$ there is only one DSF peak
corresponding to the density wave.",0802.3818v5
2012-02-06,High-temperature spin-wave propagation in BiFeO3: relation to the Polomska transition,"In bismuth ferrite thin films the cycloidal spiral spin structure is
suppressed, and as a result the spin-wave magnon branches of long wavelength
are reduced from a dozen to one, at \omega = 19.2 cm-1 (T=4K). This spin wave
has not been measured previously above room temperature, but in the present
work we show via Raman spectroscopy that it is an underdamped propagating wave
until 455 K. This has important room-temperature device implications. The data
show that \omega(T) follows an S=5/2 Brillouin function and hence its Fe+3 ions
are in the high-spin 5/2 state and not the low-spin S=1/2 state. The spin wave
cannot be measured as a propagating wave above 455 K. We also suggest that
since this temperature is coincident with the mysterious ""Polomska transition""
(M. Polomska et al., Phys. Stat. Sol. A 23, 567, (1974)) at 458+/-5 K, that
this may be due to overdamping.",1202.1040v1
2013-08-15,Spin-Wave Propagation in the Presence of Interfacial Dzyaloshinskii-Moriya Interaction,"In ferromagnetic thin films, broken inversion symmetry and spin-orbit
coupling give rise to interfacial Dzyaloshinskii-Moriya interactions. Analytic
expressions for spin-wave properties show that the interfacial
Dzyaloshinskii-Moriya interaction leads to non-reciprocal spin-wave
propagation, i.e. different properties for spin waves propagating in opposite
directions. In favorable situations, it can increase the spin-wave attenuation
length. Comparing measured spin wave properties in ferromagnet$|$normal metal
bilayers and other artificial layered structures with these calculations can
provide a useful characterization of the interfacial Dzyaloshinskii-Moriya
interactions.",1308.3341v1
2013-11-27,Quasi-2D $J_1$-$J_2$ Antiferromagnet $Zn_2VO(PO_4)_2$ and its $Ti$-substituted Derivative - A Spin-wave Analysis,"In this study, we present non-linear spin wave analysis of a quasi 2D
spin-$\frac{1}{2}$ $J_1-J_2$ antiferromagnet at the parameter regime relevant
for the recently studied compound $Zn_2VO(PO_4)_2$. We obtain the temperature
dependence of the spin wave energy, susceptibility and magnetization using
Green's function technique and Hartree-Fock factorization or Tyablikov's
decoupling approximation. The comparison of our numerical results with the
experimental findings is discussed. Magnetic structure factor is calculated and
compared with powder neutron diffraction data. We also study the spin wave
behavior of the compound $Zn_2Ti_{0.25}V_{0.75}O(PO_4)_2$ obtained by partial
chemical substitution of $Ti$ at $V$ sites of the compound $Zn_2VO(PO_4)_2$
(Phys. Rev. B87, 054431). Due to the superlattice structure of the spin
lattice, the substituted compound possess multiple spin wave modes. The spin
wave analysis confirms the quasi-1D nature of the substituted system.",1311.6915v1
2014-06-27,Spin waves along the edge states,"Spin waves have been studied experimentally and by simulations in 1000 nm
side equilateral triangular Permalloy dots in the Buckle state (B, with
in-plane field along the triangle base) and the Y state (Y, with in-plane field
perpendicular to the base). The excess of exchange energy at the triangles
edges creates channels that allow effective spin wave propagation along the
edges inthe B state. These quasi one-dimensional spin waves emitted by the
vertex magnetic charges gradually transform from propagating to standing due to
interference and(as pointed out by simulations) areweakly affected by
smallvariations of the aspect ratio(from equilateral to isosceles dots) or by
interdot dipolar interaction present in our dot arrays. Spin waves excited in
the Y state have mainly a two-dimensional character.Propagation of the spin
waves along the edge states in triangular dots opens possibilities for creation
of new and versatile spintronic devices.",1406.7200v1
2018-12-08,Directional Spin-wave Propagation in the Skyrmion Chain,"The Dzyaloshinskii-Moriya interaction (DMI), favoring a chiral spin structure
like the skyrmion, gives rise to the nonreciprocal propagation of spin waves.
We investigate the propagation of spin waves in a nanostripe with the presence
of a skyrmion chain by using micromagnetic simulations. Through applying a
microwave locally, it is found that when the interval between skyrmions is
large enough, the spin waves can be separated to the counter direction
according to different frequencies. While for the tightly arranged skyrmions,
the skyrmion chain with strong interactions between skyrmions becomes a channel
for spin waves, which is around the frequency of skyrmion breathing and exhibit
a characteristic of directional propagation. This work opens a vista for
skyrmion-based spin wave devices.",1812.03297v2
2021-04-13,Confined dipole and exchange spin waves in a bulk chiral magnet with Dzyaloshinskii-Moriya interaction,"The Dzyaloshinskii-Moriya interaction (DMI) has an impact on excited spin
waves in the chiral magnet Cu$_2$OSeO$_3$ by means of introducing asymmetry on
their dispersion relations. The confined eigenmodes of a chiral magnet are
hence no longer the conventional standing spin waves. Here we report a combined
experimental and micromagnetic modeling study by broadband microwave
spectroscopy we observe confined spin waves up to eleventh order in bulk
Cu$_2$OSeO$_3$ in the field-polarized state. In micromagnetic simulations we
find similarly rich spectra. They indicate the simultaneous excitation of both
dipole- and exchange-dominated spin waves with wavelengths down to (47.2 $\pm$
0.05) nm attributed to the exchange interaction modulation. Our results suggest
DMI to be effective to create exchange spin waves in a bulk sample without the
challenging nanofabrication and thereby to explore their scattering with
noncollinear spin textures.",2104.06240v2
2022-12-22,Hybrid Magnonic-Oscillator System,"We propose a hybrid magnonic-oscillator system based on the combination of a
spin transfer auto-oscillator and a magnonic waveguide to open new perspectives
for spin-wave based circuits. The system is composed of a spin transfer
oscillator based on a vortex state which is dipolarly coupled to a nanoscale
spin-wave waveguide with longitudinal magnetization. In its auto-oscillating
regime, the oscillator emits coherent spin waves with tunable and controllable
frequencies, directions and amplitudes into the waveguide. We demonstrate the
principle of this method using micromagnetic simulations and show that
reconfiguration of the system is possible by changing the chirality and
polarity of the magnetic vortex. Spin waves are emitted into the waveguide with
high non-reciprocity and the preferred direction depends on the core polarity
of the vortex. In contrast, different vortex chiralities lead to different
amplitudes of the emitted waves. Our findings open up a novel way to design an
agile spintronic device for the coherent and tunable generation of propagating
spin waves.",2212.11532v1
2023-07-14,Observation and control of hybrid spin-wave-Meissner-current transport modes,"Superconductors are materials with zero electrical resistivity and the
ability to expel magnetic fields known as the Meissner effect. Their
dissipationless diamagnetic response is central to magnetic levitation and
circuits such as quantum interference devices. Here, we use superconducting
diamagnetism to shape the magnetic environment governing the transport of spin
waves - collective spin excitations in magnets that are promising on-chip
signal carriers - in a thin-film magnet. Using diamond-based magnetic imaging,
we observe hybridized spin-wave-Meissner-current transport modes with strongly
altered, temperature-tunable wavelengths. We extract the temperature-dependent
London penetration depth from the wavelength shifts and realize local control
of spin-wave refraction using a focused laser. Our results demonstrate the
versatility of superconductor-manipulated spin-wave transport and have
potential applications in spin-wave gratings, filters, crystals and cavities.",2307.07581v1
2023-10-10,Spin attributes of structured vector fields constructed by Hertz potentials,"In this paper, we use the Hertz vector potential to define the
electromagnetic vector of different structured wavefields, and analyze the spin
properties of the wavefields. We show that for the single evanescent waves, the
total spin provides by the transverse spin and originates from the spatial
inhomogeneity of the momentum density of the field. However, for non-single
evanescent wave, there may be a part of the extraordinary spin component sE,
and the direction of sE is also perpendicular to the wave propagation
direction. In other words, it is transverse, but it does not originate from the
curl of the wave field momentum density. In addition, we also calculate the
spins of non-planar propagating waves, and analyze the spin characteristics of
these wave fields.",2310.06664v1
2021-06-08,"Superconducting microresonators for electron spin resonance, the good, the bad, and the future","The field of electron spin resonance is in constant need to improve its
capabilities. Among other things, this means having better resonators which
would provide improved spin sensitivity, as well as enable larger microwave
magnetic field power conversion factors. Surface micro resonators, made of
small metallic patches on a dielectric substrate, provide very good absolute
spin sensitivity and high conversion factors due to their very small mode
volume. However, such resonators suffer from having a relatively low quality
factor, which offsets some of their significant potential advantages. The use
of superconducting patches to replace the metallic layer seems like a
reasonable and straightforward solution to the quality factor issue, at least
for measurements carried out at cryogenic temperatures. Nevertheless,
superconducting materials are not easily incorporated into setups requiring
high magnetic fields, due to electric current vortices generated in the
latter's surface. This makes the transition from normal conducing materials to
superconductors highly nontrivial. Here we present the design, fabrication, and
testing results of surface micro resonators made of yttrium barium copper oxide
(YBCO) superconducting material. We show that with a unique experimental setup,
these resonators can be made to operate well even at high fields of about 1.2
T. Furthermore, we analyze the effect of current vortices on the ESR signal and
the spins' coherence times. Finally, we provide a head to head comparison of
YBCO vs copper resonators of the same dimensions, which clearly shows their
pros and cons and directs us to future potential developments and improvements
in this field.",2106.04163v2
2019-01-31,Triplet superconductivity in ferromagnets due to magnon exchange,"We consider the superconducting pairing induced by spin waves exchange in a
ferromagnet with both conduction and localized electrons, the latter being
described as spins. We use the microscopic Eliashberg theory to describe the
pairing of conducting electrons and the RPA approach to treat the localized
spins assuming an exchange coupling between the conducting electrons and spins.
In the framework of non relativistic Hamiltonian twe found that he spin wave
exchange results in equal spin electron pairing described by the two components
of the order parameter, $\Delta^{\uparrow}$ (both spins up) and
$\Delta^{\downarrow}$ (both spins down). Due to the conservation of total spin
projection on the axis of the spontaneous ferromagnetic moment, the spin wave
exchange at low temperatures includes an emission of magnons and an absorption
of thermal magnons by the conduction electrons. The absorption and emission
processes depend differently on the temperature, with the absorption being
progressively suppressed as the temperature drops. As a result, the
superconducting pairing exists only if the electron-spin wave exchange
parameter $g$ exceeds some critical value $g_c$. At $g>g_c$ pairing vanishes if
the temperature drops below the lowest point $T_{cl}$ or increases above the
upper critical point $T_{ch} \approx T_m$ (the Curie temperature) where the
spin waves cease to exist. This behavior inherent to the spin carrying glue is
in an obvious disagreement with the results of conventional BCS approach which
assumes that the effective electron-electron attraction is simply proportional
to the static magnetic susceptibility.",1901.11248v1
2006-11-09,Spin susceptibility in bilayered cuprates: resonant magnetic excitations,"We study the momentum and frequency dependence of the dynamical spin
susceptibility in the superconducting state of bilayer cuprate superconductors.
We show that there exists a resonance mode in the odd as well as the even
channel of the spin susceptibility, with the even mode being located at higher
energies than the odd mode. We demonstrate that this energy splitting between
the two modes arises not only from a difference in the interaction, but also
from a difference in the free-fermion susceptibilities of the even and odd
channels. Moreover, we show that the even resonance mode disperses downwards at
deviations from ${\bf Q}=(\pi,\pi)$. In addition, we demonstrate that there
exists a second branch of the even resonance, similar to the recently observed
second branch (the $Q^*$-mode) of the odd resonance. Finally, we identify the
origin of the qualitatively different doping dependence of the even and odd
resonance. Our results suggest further experimental test that may finally
resolve the long-standing question regarding the origin of the resonance peak.",0611267v1
2008-09-26,Top-antitop and Top-top Resonances in the Dilepton Channel at the CERN LHC,"We perform a model-independent study for top-antitop and top-top resonances
in the dilepton channel at the Large Hadtron Collider. In this channel, we can
solve the kinematic system to obtain the momenta of all particles including the
two neutrinos, and hence the resonance mass and spin. For discovering
top-antitop resonances, the dilepton channel is competitive to the semileptonic
channel because of the good resolution of lepton momentum measurement and small
standard model backgrounds. Moreover, the charges of the two leptons can be
identified, which makes the dilepton channel advantageous for discovering
top-top resonances and for distinguishing resonance spins. We discuss and
provide resolutions for difficulties associated with heavy resonances and
highly boosted top quarks.",0809.4487v2
2001-12-16,The Wave Theory of the Field,"As a substitute for the current hypothesis of space-time continuity, we show
the nature and the characteristics of a Schild's discrete space-time. With the
wave perturbations of its metrical structure we formulate the working
hypothesis that all subatomic particles are elementary sources of spherical
waves constituting on the whole the mass fields, the electromagnetic and the
nuclear field we attribute to the particles. The explicative effectiveness of
the new wave unification between quantum mechanics and general relativity is
shown by a wave interpretation of three experimental phenomena that lie
different physics: astrophysics, optics and quantum physics. A further use of
wave Compton effect leads us to discover a mechanism of wave resonance which is
able to verify the possible existence of a source of elementary waves that
shows a wave model of electron and all the particles. The wave nature of masses
and the generalized effect of a Relative Symmetry Principle leads us to
consider the inertia as a local consequence of the wave structure of bodies.
The same changeable wave model used for explaining inertia it is also valid to
show a quantized gravitational interaction and the wave nature of gravity.",0112089v1
2013-01-24,Spin transport parameters in metallic multilayers determined by ferromagnetic resonance measurements of spin pumping,"We measured spin transport in nonferromagnetic (NM) metallic multilayers from
the contribution to damping due to spin pumping from a ferromagnetic Co90Fe10
thin film. The multilayer stack consisted of NM1/NM2/Co90Fe10(2 nm)/NM2/NM3
with varying NM materials and thicknesses. Using conventional theory for one
dimensional diffusive spin transport in metals, we show that the effective
damping due to spin pumping can be strongly affected by the spin transport
properties of each NM in the multilayer, which permits the use of damping
measurements to accurately determine the spin transport properties of the
various NM layers in the full five-layer stack. We find that due to its high
electrical resistivity, amorphous Ta is a poor spin conductor, in spite of a
short spin-diffusion length of 1.0 nm, and that Pt is an excellent spin
conductor by virtue of its low electrical resistivity and a spin diffusion
length of only 0.5 nm. Spin Hall effect measurements may have underestimated
the spin Hall angle in Pt by assuming a much longer spin diffusion length.",1301.5861v1
2013-11-05,Spin accumulation detection of FMR driven spin pumping in silicon-based metal-oxide-semiconductor heterostructures,"The use of the spin Hall effect and its inverse to electrically detect and
manipulate dynamic spin currents generated via ferromagnetic resonance (FMR)
driven spin pumping has enabled the investigation of these dynamically injected
currents across a wide variety of ferromagnetic materials. However, while this
approach has proven to be an invaluable diagnostic for exploring the spin
pumping process it requires strong spin-orbit coupling, thus substantially
limiting the materials basis available for the detector/channel material
(primarily Pt, W and Ta). Here, we report FMR driven spin pumping into a weak
spin-orbit channel through the measurement of a spin accumulation voltage in a
Si-based metal-oxide-semiconductor (MOS) heterostructure. This alternate
experimental approach enables the investigation of dynamic spin pumping in a
broad class of materials with weak spin-orbit coupling and long spin lifetime
while providing additional information regarding the phase evolution of the
injected spin ensemble via Hanle-based measurements of the effective spin
lifetime.",1311.0965v1
2014-11-14,Broadband resonances in ITO nanorod arrays,"In the nanophotonics community, there is an active discussion regarding the
origin of the selective absorption/scattering of light by the resonances with
nanorod arrays. Here we report a study of the resonances in ordered
indium-tin-oxide (ITO) nanorod arrays resulted from the waveguide modes. We
discover that with only 2.4% geometrical coverage, the micron-length nanorod
arrays strongly interact with light across an extra-wide band from visible to
mid-infrared resulting in less than 10% transmission. Simulations show
excellent agreement with our experimental observation. Near-field profile
obtained from simulation reveals the electric field is mainly localized on the
surfaces of the nanorods at all the resonances. Theoretical analysis is then
applied to explain the resonances and it was found that the resonances in the
visible are different from those in the infrared. When the light arrives at the
array, part of the light wave propagates through the free space in between the
nanorods and part of the wave is guided inside the nanorods and the phase
difference at the ends of the rod interactions forms the basis of the
resonances in the visible region; while the resonances in the infrared are
Fabry-Perot resonances of the surface guided waves between the two ends of the
nanorods. The simple analytical formulae developed predict the spectral
positions of these resonances well. This information can be used to design
devices like wavelength-selective photodetector, modulators, and nanorod-based
solar cells.",1411.3767v2
2022-05-11,Mathematical theory for electromagnetic scattering resonances and field enhancement in a subwavelength annular gap,"This work presents a mathematical theory for electromagnetic scattering
resonances in a subwavelength annular hole embedded in a metallic slab, with
the annulus width $h\ll1$. The model is representative among many 3D
subwavelength hole structures, which are able to induce resonant scattering of
electromagnetic wave and the so-called extraordinary optical transmission. We
develop a multiscale framework for the underlying scattering problem based upon
a combination of the integral equation in the exterior domain and the waveguide
mode expansion inside the tiny hole. The matching of the electromagnetic field
over the hole aperture leads to a sequence of decoupled infinite systems, which
are used to set up the resonance conditions for the scattering problem. By
performing rigorous analysis for the infinite systems and the resonance
conditions, we characterize all the resonances in a bounded domain over the
complex plane. It is shown that the resonances are associated with the TE and
TEM waveguide modes in the annular hole, and they are close to the real axis
with the imaginary parts of order ${\cal O}(h)$. We also investigate the
resonant scattering when an incident wave is present. It is proved that the
electromagnetic field is amplified with order ${\cal O}(1/h)$ at the resonant
frequencies that are associated with the TE modes in the annular hole. On the
other hand, one particular resonance associated with the TEM mode can not be
excited by a plane wave but can be excited with a near-field electric dipole
source, leading to field enhancement of order ${\cal O}(1/h)$.",2205.05377v1
2017-02-20,Environmentally mediated coherent control of a spin qubit in diamond,"The coherent control of spin qubits forms the basis of many applications in
quantum information processing and nanoscale sensing, imaging and spectroscopy.
Such control is conventionally achieved by direct driving of the qubit
transition with a resonant global field, typically at microwave frequencies.
Here we introduce an approach that relies on the resonant driving of nearby
environment spins, whose localised magnetic field in turn drives the qubit when
the environmental spin Rabi frequency matches the qubit resonance. This concept
of environmentally mediated resonance (EMR) is explored experimentally using a
qubit based on a single nitrogen-vacancy (NV) centre in diamond, with nearby
electronic spins serving as the environmental mediators. We demonstrate EMR
driven coherent control of the NV spin-state, including the observation of Rabi
oscillations, free induction decay, and spin-echo. This technique also provides
a way to probe the nanoscale environment of spin qubits, which we illustrate by
acquisition of electron spin resonance spectra of single NV centres in various
settings.",1702.05822v1
2018-11-14,Spin detection with a micromechanical trampoline: Towards magnetic resonance microscopy harnessing cavity optomechanics,"We explore the prospects and benefits of combining the techniques of cavity
optomechanics with efforts to image spins using magnetic resonance force
microscopy (MRFM). In particular, we focus on a common mechanical resonator
used in cavity optomechanics -- high-stress stoichiometric silicon nitride
(Si$_3$N$_4$) membranes. We present experimental work with a trampoline
membrane resonator that has a quality factor above $10^6$ and an order of
magnitude lower mass than a comparable standard membrane resonators. Such
high-stress resonators are on a trajectory to reach 0.1
$\rm{aN}/\sqrt{\rm{Hz}}$ force sensitivities at MHz frequencies by using
techniques such as soft clamping and phononic-crystal control of acoustic
radiation in combination with cryogenic cooling. We present a demonstration of
force-detected electron spin resonance of an ensemble at room temperature using
the trampoline resonators functionalized with a magnetic grain. We discuss
prospects for combining such a resonator with an integrated Fabry-Perot cavity
readout at cryogenic temperatures, and provide ideas for future impacts of
membrane cavity optomechanical devices on MRFM of nuclear spins.",1811.05718v2
2020-03-26,Magnetoelastic waves in thin films,"This paper discusses the physics of magnetoelasticity and magnetoelastic
waves as well as their mathematical description. Magnetoelastic waves occur as
a result of strong coupling between spin waves and elastic waves in
magnetostrictive ferromagnetic media. In a first part, the basic behavior of
spin waves is reviewed in both bulk ferromagnets as well as in thin films.
Next, elastic waves are discussed with a focus on thin films. Finally, the
interactions between the elastic and magnetic domains are described and it is
shown how this results in the formation of magnetoelastic waves. Based on the
description of bulk magnetoelastic waves, a theory for magnetoelastic waves in
thin films is developed and their dispersion relations are derived. It is shown
that the behavior strongly depends on the geometry of the system, especially on
the polarization of spin and elastic waves and the direction of the
magnetization of the magnetostrictive ferromagnet.",2003.12099v1
2015-03-13,Spin-wave logic devices based on isotropic forward volume magneto-static waves,"We propose the utilization of isotropic forward volume magneto-static spin
waves in modern wave-based logic devices and suggest a concrete design for a
spin-wave majority gate operating with these waves. We demonstrate by numerical
simulations that the proposed out-of-plane magnetized majority gate overcomes
the limitations of anisotropic in-plane magnetized majority gates due to the
high spin-wave transmission through the gate, which enables a reduced energy
consumption of these devices. Moreover, the functionality of the out-of-plane
majority gate is increased due to the lack of parasitic generation of
short-wavelength exchange spin waves.",1503.04101v1
2022-01-11,Parametric Excitation and Instabilities of Spin Waves driven by Surface Acoustic Waves,"The parametric excitation of spin waves by coherent surface acoustic waves is
demonstrated experimentally in metallic magnetic thin film structures. The
involved magnon modes are analyzed with micro-focused Brillouin light
scattering spectroscopy and complementary micromagnetic simulations combined
with analytical modelling are used to determine the origin of the spin-wave
instabilities. Depending on the experimental conditions, we observe spin-wave
instabilities originating from different phonon-magnon and magnon-magnon
scattering processes. Our results demonstrate that an efficient excitation of
high amplitude, strongly nonlinear magnons in metallic ferromagnets is possible
by surface acoustic waves, which opens novel ways to create micro-scaled
nonlinear magnonic systems for logic and data processing that can profit from
the high excitation efficiency of phonons using piezoelectricity.",2201.04033v2
2011-08-05,Magnons and electromagnons in a spin-lattice-coupled frustrated magnet CuFeO2 as seen via inelastic neutron scattering,"We have investigated spin-wave excitations in a four-sublattice (4SL)
magnetic ground state of a frustrated magnet CuFeO2, in which `electromagnon'
(electric-field-active magnon) excitation has been discovered by recent
terahertz time-domain spectroscopy [Seki et al. Phys. Rev. Lett. 105 097207
(2010)]. In previous study, we have identified two spin-wave branches in the
4SL phase by means of inelastic neutron scattering measurements under applied
uniaxial pressure. [T. Nakajima et al. J. Phys. Soc. Jpn. 80 014714 (2011) ] In
the present study, we have performed high-energy-resolution inelastic neutron
scattering measurements in the 4SL phase, resolving fine structures of the
lower-energy spin-wave branch near the zone center. Taking account of the
spin-driven lattice distortions in the 4SL phase, we have developed a model
Hamiltonian to describe the spin-wave excitations. The determined Hamiltonian
parameters have successfully reproduced the spin-wave dispersion relations and
intensity maps obtained in the inelastic neutron scattering measurements. The
results of the spin-wave analysis have also revealed physical pictures of the
magnon and electromagnon modes in the 4SL phase, suggesting that collinear and
noncollinear characters of the two spin-wave modes are the keys to understand
the dynamical coupling between the spins and electric dipole moments in this
system.",1108.1297v1
2013-07-22,Topological quantum phase transition in Kane-Mele-Kondo lattice model,"We systematically explore the ground-state phase diagram of the
Kane-Mele-Kondo lattice model on the honeycomb lattice, in particular, we focus
on its magnetic properties which has not been studied in the previous
publication[Feng, Dai, Chung, and Si, Phys. Rev. Lett. \textbf{111}, 016402
(2013)]. Beside the Kondo insulator found in that paper, two kinds of
antiferromagnetic spin-density-wave phases are identified. One is the normal
antiferromagnetic spin-density-wave state and the other is a nontrivial
topological antiferromagnetic spin-density-wave state with a quantized spin
Hall conductance and a helical edge-state. The quantum spin Hall insulator is
found to be absent since it is always unstable to antiferromagnetic
spin-density-wave states at least at the mean-field level in our model.
Furthermore, the transition between the two spin-density-wave phases are
topological quantum phase transition described by the three-dimensional quantum
electrodynamics, in which conduction electrons contribute to the low-energy
Dirac fermions while the spin-wave fluctuation of local spins gives rise to an
effective dynamic U(1) gauge-field. Such nontrivial transition shows radical
critical thermodynamic, transport and single-particle behaviors, which provide
a fingerprint for this transition. Additionally, the transition of
antiferromagnetic spin-density-wave states to the Kondo insulator is found to
be first-order. The introduction of two novel magnetic phases and their
topological quantum phase transition show rich and intrinsic physics involving
in the Kane-Mele-Kondo lattice model.",1307.5627v2
2003-10-16,Spin Torque and its Relation to Spin Filtering,"The spin torque exerted on a magnetic moment is a reaction to spin filtering
when spin-polarized electrons interact with a thin ferromagnetic film. We show
that, for certain conditions, a spin transmission resonance (STR) gives rise to
a failure of spin filtering. As a consequence, no spin is transfered to the
ferromagnet. The condition for STR depends on the incoming energy of electrons
and the thickness of the film. For a simple model we find that when the STR
condition is satisfied, the ferromagnetic film is transparent to the incoming
electrons.",0310392v1
2011-05-24,Scalable Spin Amplification with a Gain over a Hundred,"We propose a scalable and practical implementation of spin amplification
which does not require individual addressing nor a specially tailored spin
network. We have demonstrated a gain of 140 in a solid-state nuclear spin
system of which the spin polarization has been increased to 0.12 using dynamic
nuclear polarization with photoexcited triplet electron spins. Spin
amplification scalable to a higher gain opens the door to the single spin
measurement for a readout of quantum computers as well as practical
applications of nuclear magnetic resonance (NMR) spectroscopy to infinitesimal
samples which have been concealed by thermal noise.",1105.4740v1
2014-08-25,Disentangling the Spin-Parity of a Resonance via the Gold-Plated Decay Mode,"Searching for new resonances and finding out their properties is an essential
part of any existing or future particle physics experiment. The nature of a new
resonance is characterized by its spin, charge conjugation, parity, and its
couplings with the existing particles of the Standard Model. If a new resonance
is found in the four lepton final state produced via two intermediate $Z$
bosons, the resonance could be a new heavy scalar or a $Z'$ boson or even a
higher spin particle. In such cases the step by step methodology as enunciated
in this paper can be followed to determine the spin, parity and the coupling to
two $Z$ bosons of the parent particles, in a fully model-independent way. In
our approach we show how three uni-angular distributions and few experimentally
measurable observables can conclusively tell us about the spin, parity as well
as the couplings of the new resonance to two $Z$ bosons. We have performed a
numerical analysis to validate our approach and showed how the uniangular
observables can be used to disentangle the spin parity as well as coupling of
the resonance.",1408.5665v2
2019-01-10,High-cooperativity coupling of a rare-earth spin ensemble to a superconducting resonator using yttrium orthosilicate as a substrate,"Yttrium orthosilicate (Y$_2$SiO$_5$, or YSO) has proved to be a convenient
host for rare-earth ions used in demonstrations of microwave quantum memories
and optical memories with microwave interfaces, and shows promise for coherent
microwave--optical conversion owing to its favourable optical and spin
properties. The strong coupling required by such microwave applications could
be achieved using superconducting resonators patterned directly on
Y$_2$SiO$_5$, and hence we investigate here the use of Y$_2$SiO$_5$ as an
alternative to sapphire or silicon substrates for superconducting hybrid device
fabrication. A NbN resonator with frequency 6.008 GHz and low power quality
factor $Q \approx 400000$ was fabricated on a Y$_2$SiO$_5$ substrate doped with
isotopically enriched Nd$^{145}$. Measurements of dielectric loss yield a
loss-tangent $\tan\delta = 4 \times 10^{-6}$, comparable to sapphire. Electron
spin resonance (ESR) measurements performed using the resonator show the
characteristic angular dependence expected from the anisotropic Nd$^{145}$
spin, and the coupling strength between resonator and electron spins is in the
high cooperativity regime ($C = 30$). These results demonstrate Y$_2$SiO$_5$ as
an excellent substrate for low-loss, high-Q microwave resonators, especially in
applications for coupling to optically-accessible rare earth spins.",1901.03262v2
2020-07-15,Spin resonance linewidths of bismuth donors in silicon coupled to planar microresonators,"Ensembles of bismuth donor spins in silicon are promising storage elements
for microwave quantum memories due to their long coherence times which exceed
seconds. Operating an efficient quantum memory requires achieving critical
coupling between the spin ensemble and a suitable high-quality factor resonator
-- this in turn requires a thorough understanding of the lineshapes for the
relevant spin resonance transitions, particularly considering the influence of
the resonator itself on line broadening. Here, we present pulsed electron spin
resonance measurements of ensembles of bismuth donors in natural silicon, above
which niobium superconducting resonators have been patterned. By studying spin
transitions across a range of frequencies and fields we identify distinct line
broadening mechanisms, and in particular those which can be suppressed by
operating at magnetic-field-insensitive `clock transitions'. Given the donor
concentrations and resonator used here, we measure a cooperativity $C\sim 0.2$
and based on our findings we discuss a route to achieve unit cooperativity, as
required for a quantum memory.",2007.07600v3
2022-12-07,Surfing in the phase space of spin-orbit coupling in binary asteroid systems,"For a satellite with an irregular shape, which is the common shape among
asteroids, the well-known spin-orbit resonance problem could be changed to a
spin-orbit coupling problem since a decoupled model does not accurately capture
the dynamics of the system. In this paper, having provided a definition for
close binary asteroid systems, we explore the structure of the phase space in a
classical Hamiltonian model for spin-orbit coupling in a binary system. To map
out the geography of resonances analytically and the cartography of resonances
numerically, we reformulate a fourth-order gravitational potential function, in
Poincare variables, via Stokes coefficients. For a binary system with a
near-circular orbit, isolating the Hamiltonian near each resonance yields the
pendulum model. Analysis of the results shows the geographical information,
including the location and width of resonances, is modified due to the
prominent role of the semi-major axis in the spin-orbit coupling model but not
structurally altered. However, this resulted in modified Chirikov criterion to
predict onset of large-scale chaos. For a binary system with arbitrary closed
orbit, we thoroughly surf in the phase space via cartography of resonances
created by fast Lyapunov indicator (FLI) maps. The numerical study confirms the
analytical results, provides insight into the spin-orbit coupling, and shows
some bifurcations in the secondary resonances which can occur due to material
transfer. Also, we take the (65803) Didymos binary asteroid as a case to show
analytical and numerical results.",2212.03837v1
2008-01-08,Spin-dependent transition rates through exchange coupled localized spin pairs during coherent spin excitation,"The effect of exchange interactions within spin pairs on spin-dependent
transport and recombination rates through localized states in semiconductors
during coherent electron spin resonant excitation is studied theoretically. It
is shown that for identical spin systems, significant quantitative differences
are to be expected between the results of pEDMR/pODMR experiments were
permutation symmetry is the observable as compared to pESR experiments with
polarization as the observable. It is predicted that beat oscillations of the
spin nutations and not the nutations themselves dominate the transport or
recombination rates when the exchange coupling strength or the field strength
of the exciting radiation exceed the difference of the Zeeman energies within
the spin pair. Furthermore, while the intensities of the rate oscillations
decrease with increasing exchange within the spin pairs, the singlet and
triplet signals retain their relative strength. This means that pEDMR and pODMR
experiments could allow better experimental access to ESR forbidden singlet
transitions which are hardly or not at all accessible with conventional pulsed
electron spin resonance spectroscopy.",0801.1304v2
2011-10-28,Spin Lifetime in Small Electron Spin Ensembles Measured by Magnetic Resonance Force Microscopy,"Magnetic Resonance Force Microscopy can enable nanoscale imaging of spin
lifetime. We report temperature dependent measurements of the spin correlation
time $\tau_m$ of the statistical fluctuations of the spin polarization---the
spin noise---of ensembles containing $\sim 100$ electron spins by this
technique. Magneto-mechanical relaxation due to spin-cantilever coupling was
controlled and spurious mechanisms that can affect the spin correlation time of
the microscopic signal were characterized. These measurements have
ramifications for optimizing spin sensitivity, understanding local spin
dynamics and for nanoscale imaging.",1110.6410v1
2011-12-29,Coherent spin dynamics of electrons and holes in semiconductor quantum wells and quantum dots under periodical optical excitation: resonant spin amplification versus spin mode-locking,"The coherent spin dynamics of resident carriers, electrons and holes, in
semiconductor quantum structures is studied by periodical optical excitation
using short laser pulses and in an external magnetic field. The generation and
dephasing of spin polarization in an ensemble of carrier spins, for which the
relaxation time of individual spins exceeds the repetition period of the laser
pulses, are analyzed theoretically. Spin polarization accumulation is
manifested either as resonant spin amplification or as mode-locking of carrier
spin coherences. It is shown that both regimes have the same origin, while
their appearance is determined by the optical pump power and the spread of spin
precession frequencies in the ensemble.",1112.6404v1
2013-07-09,Spin-noise correlations and spin-noise exchange driven by low-field spin-exchange collisions,"The physics of spin exchange collisions have fueled several discoveries in
fundamental physics and numerous applications in medical imaging and nuclear
magnetic resonance. We here report on the experimental observation and
theoretical justification of spin-noise exchange, the transfer of spin-noise
from one atomic species to another. The signature of spin-noise exchange is an
increase of the total spin-noise power at low magnetic fields, on the order of
1 mG, where the two-species spin-noise resonances overlap. The underlying
physical mechanism is the two-species spin-noise correlation induced by
spin-exchange collisions.",1307.2596v3
2020-08-20,Polarization amplification by spin-doping in nanomagnetic/graphene hybrid systems,"The generation of non-equilibrium electron spin polarization, spin transport,
and spin detection are fundamental in many quantum devices. We demonstrate that
a lattice of magnetic nanodots enhances the electron spin polarization in
monolayer graphene via carrier exchange. We probed the spin polarization
through a resistively-detected variant of electron spin resonance (ESR) and
observed resonance amplification mediated by the presence of the nanodots. Each
nanodot locally injects a surplus of spin-polarized carriers into the graphene,
and the ensemble of all ""spin hot spots"" generates a non-equilibrium electron
spin polarization in the graphene layer at macroscopic lengths. This occurs
whenever the interdot distance is comparable or smaller than the spin diffusion
length.",2008.08813v2
2019-09-16,Spin current pumped by resonant skyrmion,"Spin pumping is a widely recognized method to generate the spin current in
the spintronics, which is acknowledged as a fundamentally dynamic process
equivalent to the spin-transfer torque. In this work, we theoretically verify
that the oscillating spin current can be pumped from the microwave-motivated
breathing skyrmion. The skyrmion spin pumping can be excited by a relatively
low frequency compared with the ferromagnetic resonance (FMR) and the current
density is larger than the ordinary FMR spin pumping. Based on the skyrmion
spin pumping, we build a high reading-speed racetrack memory model whose
reading speed is an order of magnitude higher than the SOT (spin-orbit torque)
/STT (spin-transfer torque) skyrmion racetrack. Our work explored the spin
pumping phenomenon in the skyrmion, and it may contribute to the applications
of the skyrmion-based device.",1909.07077v1
2022-08-19,Measurement-induced nuclear spin polarization,"We propose a nuclear-spin-polarization protocol in a general
evolution-and-measurement framework. The protocol works in a spin-star
configuration, where the central spin is coupled to the surrounding bath
(nuclear) spins by flip-flop interaction of equal strength and is subject to a
sequence of projective measurements on its ground state. Then a
nondeterministic nuclear spin polarization could be implemented by entropy
reduction through measurement. The optimized measurement-interval $\tau_{\rm
opt}$ is analytically obtained in the near-resonant condition, which is
relevant to the nuclear spins' polarization degree of the last-round
measurement, the number of nuclear spins, and the coupling strength between the
central spin and nuclear spins. Hundreds and even thousands of randomly aligned
nuclear spins at the thermal state could be almost fully polarized with an
optimized sequence of less than $20$ unequal-time-spacing measurements. In
comparison to the conventional approaches, our protocol is not sensitive to the
magnetic-field intensity, and it is robust against the extra counterrotating
interaction in the near-resonant situation.",2208.09113v2
2023-02-23,Photo-assisted spin transport in double quantum dots with spin-orbit interaction,"We investigate the effect of spin-orbit interaction on the intra- and
interdot particle dynamics of a double quantum dot under ac electric fields.
The former is modeled as an effective ac magnetic field that produces
electric-dipole spin resonance transitions, while the latter is introduced via
spin-flip tunneling amplitudes. We observe the appearance of non-trivial
spin-polarized dark states, arising from an ac-induced interference between
photo-assisted spin-conserving and spin-flip tunneling processes. These dark
states can be employed to precisely measure the spin-orbit coupling in quantum
dot systems. Furthermore, we show that the interplay between photo-assisted
transitions and spin-flip tunneling allows the system to operate as a highly
tunable spin filter. Finally, we investigate the operation of the system as a
resonant flopping-mode qubit for arbitrary ac voltage amplitudes, allowing for
high tunability and enhanced qubit control possibilities.",2302.12272v2
1998-02-25,Extensive spiral structure and corotation resonance,"Spiral density wave theories demand that grand design spiral structure be
bounded, at most, between the inner and outer Lindblad resonances of the spiral
pattern. The corotation resonance lies between the outer and inner Lindblad
resonances. The locations of the resonances are at radii whose ratios to each
other are rather independent of the shape of the rotation curve. The measured
ratio of outer to inner extent of spiral structure for a given spiral galaxy
can be compared to the standard ratio of corotation to inner Lindblad resonance
radius. In the case that the measured ratio far exceeds the standard ratio, it
is likely that the corotation resonance is within the bright optical disk.
Studying such galaxies can teach us how the action of resonances sculpts the
appearance of spiral disks. This paper reports observations of 140 disk
galaxies, leading to resonance ratio tests for 109 qualified spirals. It lists
candidates that have a good chance of having the corotation resonance radius
within the bright optical disk.",9802325v1
2017-06-28,Towards N-mode parametric electromechanical resonances,"The ubiquity of parametric resonance is continually evident in the repeated
experimental observations of this phenomenon in multiple physical systems. The
elementary case of 2 mode parametric resonance of order 1 involves the
excitation of a spectral tone of a parametrically driven mode at a sub-harmonic
frequency of the higher directly driven mode. Historically, such examples of
parametric resonance have been predominantly researched in a system of micro-
and nanoelectromechanical resonators. Here, in this paper, we break this
convention by showcasing a collection of experimental signatures in support of
the concept of ""N-mode parametric resonance"" using a number of elementary
microelectromechanical devices. Specifically, we present observations of 2, 3,
(2+3) and (3+3) mode parametric resonances demonstrating co-existence of
different regimes within the same device. In addition, we also present
observations of intrinsic ""Four-Wave Mixing"" of parametric excitations. This
paper presents contributions towards the existence proof for such multimode
parametric resonances which can also be exploited for engineering benefit
within the field of ""micro and nanoelectromechanical resonators"". The
experimental results further point towards the possibility of the ultimate
observation of N-mode parametric resonance in such physical system.",1708.01660v1
2017-06-22,Multipole resonances and directional scattering by hyperbolic-media antennas,"We propose to use optical antennas made out of natural hyperbolic material
hexagonal boron nitride (hBN), and we demonstrate that this medium is a
promising alternative to plasmonic and all-dielectric materials for realizing
efficient subwavelength scatterers and metasurfaces based on them. We
theoretically show that particles out of hyperbolic medium possess different
resonances enabled by the support of high-k waves and their reflection from the
particle boundaries. Among those resonances, there are electric quadrupole
excitations, which cause magnetic resonance of the particle similar to what
occurs in high-refractive-index particles. Excitations of the particle
resonances are accompanied by the drop in the reflection from nanoparticle
array to near-zero value, which can be ascribed to resonant Kerker effect. If
particles are arranged in the spacer array with period d, narrow lattice
resonances are possible at wavelength d, d/2, d/3 etc. This provides an
additional degree of control and possibility to excite resonances at the
wavelength defined by the array spacing. For the hBN particle with hyperbolic
dispersion, we show that the full range of the resonances, including magnetic
resonance and a decrease of reflection, is possible.",1706.07259v1
2002-07-17,Exploration of Resonant Continuum and Giant Resonance in the Relativistic Approach,"Single-particle resonant-states in the continuum are determined by solving
scattering states of the Dirac equation with proper asymptotic conditions in
the relativistic mean field theory (RMF). The regular and irregular solutions
of the Dirac equation at a large radius where the nuclear potentials vanish are
relativistic Coulomb wave functions, which are calculated numerically.
Energies, widths and wave functions of single-particle resonance states in the
continuum for ^{120}Sn are studied in the RMF with the parameter set of NL3.
The isoscalar giant octupole resonance of ^{120}Sn is investigated in a fully
consistent relativistic random phase approximation. Comparing the results with
including full continuum states and only those single-particle resonances we
find that the contributions from those resonant-states dominate in the nuclear
giant resonant processes.",0207054v1
2009-02-15,Effects of Electric Fields on Heteronuclear Feshbach Resonances in Ultracold $^6\rm{Li}-^{87}\rm{Rb}$ Mixtures,"The effects of combined external electric and magnetic fields on elastic
collisions in ultracold Li--Rb mixtures is studied using recently obtained,
experimentally verified potentials. Our analysis provides both quantitative
predictions for and a detailed physical interpretation of the phenomena arising
from electric-field-induced interactions. It is shown that the electric field
shifts the positions of intrinsic magnetic Feshbach resonances, generates
copies of resonances previously restricted to a particular partial-wave
collision to other partial wave channels, and splits Feshbach resonances into
multiple resonances for states of non-zero angular momenta. It was recently
observed that the magnetic dipole-dipole interaction can also lift the
degeneracy of a p-wave state splitting the associated p-wave Feshbach resonance
into two distinct resonances at different magnetic fields. Our work shows that
the splitting of the resonances produced by an applied electric field is more
than an order of magnitude larger. This new phenomenon offers a complementary
way to produce and tune an anisotropic interaction and to study its effect on
the many-body physics of heteronuclear atomic gases.",0902.2505v1
2017-08-10,Acoustic resonance in periodically sheared glass,"Using molecular dynamics simulation, we study acoustic resonance in
low-temperature glass by applying a small periodic shear at a boundary wall.
Shear wave resonance occurs as the frequency $\omega$ approaches $\omega_\ell=
\pi c_\perp\ell/L$ ($\ell=1, 2, 3,...)$. Here, $c_\perp$ is the transverse
sound speed and $L$ is the cell length. At resonance, large-amplitude sound
waves appear after many cycles even for very small applied strains. They then
induce plastic events, which are heterogeneous in space and intermittent on
time scales longer than the oscillation period $2\pi/\omega$. From these
irreversible particle motions, there arises strong dissipation suppressing the
growth of sounds. After many resonant cycles, we observe a phenomenon of forced
aging, where the shear modulus (measured after switching off the oscillation)
is increased significantly.Sometimes, exceptionally large plastic events and
system-size sliding motions induce a transition from resonant to off-resonant
states. At resonance, translational diffusion becomes appreciable as well as
aging due to enhanced configurational changes.",1708.03166v2
2018-03-30,Bloch-Floquet waves in optical ring resonators,"Modal coupling between frequency-degenerate resonances of an optical ring
resonator is a commonly observed phenomenon that results in adverse mode
splitting. Traditionally, this coupling is attributed to Rayleigh scattering of
a propagating electromagnetic wave into its associated degenerate
counter-propagating mode from small perturbations to the dielectric material of
the resonator. We have chosen to reframe the problem of intracavity Rayleigh
scattering by considering the optical ring resonator as an infinitely-long,
one-dimensional photonic crystal (PhC) that possesses a lattice constant equal
to the perimeter of the ring. Through application of Bloch-Floquet theory, we
show that modal coupling between degenerate resonances of a ring can
effectively be described as the formation of photonic frequency bands in the
dispersion relation of the resonator. We additionally demonstrate that the
Bragg planes of the PhC lattice coincide with the phase matching conditions for
constructive interference in the ring. Finally, we show that the magnitude of
frequency splitting of a particular resonance is proportional to its associated
coefficient in the Fourier expansion of the ring's periodic dielectric
function.",1803.11312v1
2018-10-05,Resonant spectra of multipole-bound anions,"In multipole-bound anions, the excess electron is attached by a short-range
multipole potential of a neutral molecule. Such anions are prototypical
marginally-bound open quantum systems. In particular, around the critical
multipole moment required to attach the valence electron, multipole-bound
anions exhibit critical behavior associated with a transition from bound states
dominated by low-$\ell$ partial waves to the electron continuum. In this work,
multipole-bound anions are described using a nonadiabatic electron-plus-rotor
model. The electron-molecule pseudo-potential is represented by a short-range
multipole field with a Gaussian form-factor. The resulting coupled-channel
Schr\""odinger equation is solved by means of the Berggren expansion method, in
which the electron's wave function is decomposed into bound states, narrow
resonances, and the non-resonant scattering continuum. We show that the
Gaussian model predicts the critical transition at the detachment threshold.
Resonant states, including bound states, decaying resonances, subthreshold
resonances, and antibound states are studied, and exceptional points where two
resonant states coalesce are predicted. We discuss the transition of rotational
band structures around the threshold and study the effects of channel coupling
on the decay width of resonant poles.",1810.02806v2
2014-06-20,Effective Medium Theory for Elastic Metamaterials in Thin Elastic Plates,"An effective medium theory for resonant and non-resonant metamaterials for
flexural waves in thin plates is presented. The theory provides closed-form
expressions for the effective parameters of arrangement of inclusions or
resonators in thin plates as a function of the filling fraction of the
inclusions, their physical properties and the frequency. It is shown that
positive or negative effective elastic parameters are possible depending on the
symmetry of the resonance but, unlike it happens for bulk elastic waves, the
responsible for the negative mass density behaviour is the monopolar term,
while the negative Young's modulus and Poisson's ratio is due to the
combination of monopolar and quadrupolar resonances, showing also that, at
least for the first order in the scattering coefficients, the dipolar resonance
plays no role in the description of the effective medium. Several examples are
given for both non-resonant and resonant effective parameters and the results
are verified by multiple scattering theory.",1406.5400v2
2020-10-31,Long-term dynamics driven by resonant wave-particle interactions: from Hamiltonian resonance theory to phase space mapping,"In this study we consider the Hamiltonian approach for the construction of a
map for a system with nonlinear resonant interaction, including phase trapping
and phase bunching effects. We derive basic equations for a single resonant
trajectory analysis and then generalize them into the map in the
energy/pitch-angle space. The main advances of this approach are the
possibility to consider effects of many resonances and to simulate the
evolution of the resonant particle ensemble on long time ranges. For
illustrative purposes we consider the system with resonant relativistic
electrons and field-aligned whistler-mode waves. The simulation results show
that the electron phase space density within the resonant region is flattened
with reduction of gradients. This evolution is much faster than the predictions
of quasi-linear theory. We discuss further applications of the proposed
approach and possible ways for its generalization.",2011.00208v1
2022-01-19,Observation of the P-wave Shape Resonance,"Partial wave resonances are quasi-bound states that are formed by tunneling
through the centrifugal barrier. Such states are important to collisions that
deviate from the Langevin limit where direct collision path is suppressed due
to quantum symmetry or a potential barrier. In such a case, quantum resonances
play a major role in the dynamics at low temperatures where scattering process
can be described mainly by the resonance contribution. Here we present the
first observation of the lowest-lying partial wave resonance in the Penning
ionization collisions between metastable neon and rovibrationally ground state
HD molecules. We observe the resonance at an energy of $k_B\times$22mK taking
advantage of the phase space correlation similar to atomic delta kick cooling.
We show that the $p$-wave resonance position is particularly sensitive to the
leading term of the van der Waals interaction. We also measure shape resonance
at a higher angular momentum state, $l=6$, allowing us to disentangle and probe
the short and the long parts of the intermolecular interaction.",2201.07716v2
2023-06-11,Resonant dynamics of extreme mass-ratio inspirals in a perturbed Kerr spacetime,"Extreme mass-ratio inspirals (EMRI) are one of the most sensitive probes of
black hole spacetimes with gravitational wave measurements. In this work, we
systematically analyze the dynamics of an EMRI system near orbital resonances,
assuming the background spacetime is weakly perturbed from Kerr. Using the
action-angle formalism, we have derived an effective resonant Hamiltonian that
describes the dynamics of the resonant degree of freedom, for the case that the
EMRI motion across the resonance regime. This effective resonant Hamiltonian
can also be used to derive the condition that the trajectory enters/exits a
resonant island and the permanent change of action variables across the
resonance with the gravitational wave radiation turned on. The orbital chaos,
on the other hand, generally leads to transitions between different branches of
rotational orbits with finite changes of the action variables. These findings
are demonstrated with numerical orbital evolutions that are mapped into
representations using action-angle variables. This study is one part of the
program of understanding EMRI dynamics in a generic perturbed Kerr spacetime,
which paves the way of using EMRIs to precisely measure the black hole
spacetime.",2306.06576v2
2006-12-12,Electric-Field-Induced Resonant Spin Polarization in a Two-Dimensional Electron Gas,"Electric response of spin polarization in two-dimensional electron gas with
structural inversion asymmetry subjected to a magnetic field was studied by
means of the linear and non-linear theory and numerical simulation with the
disorder effect. It was found by Kubo linear reponse theory that an electric
resonant response of spin polarization occurs when the Fermi surface is located
near the crossing of two Landau levels, which is induced from the competition
between the spin-orbit coupling and Zeeman splitting. The scaling behavior was
investigated with a simplified two-level model by non-linear method, and the
resonant peak value is reciprocally proportional to the electric field at low
temperatures and to temperature for finite electric fields. Finally numerical
simulation illustrated that impurity potential opens an enegy gap near the
resonant point and suppresses the effect gradually with the increasing strength
of disorder. This resonant effect may provide an efficient way to control spin
polarization by an external electric field.",0612277v2
2007-08-14,Triplet spin resonance of the Haldane compound with interchain coupling,"Spin resonance absorption of the triplet excitations is studied
experimentally in the Haldane magnet PbNi2V2O8. The spectrum has features of
spin S=1 resonance in a crystal field, with all three components, corresponding
to transitions between spin sublevels, being observable. The resonance field is
temperature dependent, indicating the renormalization of excitation spectrum in
interaction between the triplets. Magnetic resonance frequencies and critical
fields of the magnetization curve are consistent with a boson version of the
macroscopic field theory [Affleck 1992, Farutin & Marchenko 2007], implying the
field induced ordering at the critical field, while contradict the previously
used approach of noninteracting spin chains.",0708.1904v1
2007-11-09,A Digital Switch and Femto-Tesla Magnetic Field Sensor Based on Fano Resonance in a Spin Field Effect Transistor,"We show that a Spin Field Effect Transistor, realized with a semiconductor
quantum wire channel sandwiched between half-metallic ferromagnetic contacts,
can have Fano resonances in the transmission spectrum. These resonances appear
because the ferromagnets are half-metallic, so that the Fermi level can be
placed above the majority but below the minority spin band. In that case, the
majority spins will be propagating, but the minority spins will be evanescent.
At low temperatures, the Fano resonances can be exploited to implement a
digital binary switch that can be turned on or off with a very small gate
voltage swing of few tens of microvolts, leading to extremely small dynamic
power dissipation during switching. An array of 500,000 x 500,000 such
transistors can detect ultrasmall changes in a magnetic field with a
sensitivity of 1 femto-Tesla/sqrt{Hz}, if each transistor is biased near a Fano
resonance.",0711.1475v1
2008-03-03,Resonant spin-changing collisions in spinor Fermi gases,"Spin-changing collisions in trapped Fermi gases may acquire a resonant
character due to the compensation of quadratic Zeeman effect and trap energy.
These resonances are absent in spinor condensates and pseudo-spin-1/2 Fermi
gases, being a characteristic feature of high-spin Fermi gases that allows
spinor physics at large magnetic fields. We analyze these resonances in detail
for the case of lattice spinor fermions, showing that they permit to
selectively target a spin-changing channel while suppressing all others. These
resonances allow for the controlled creation of non-trivial quantum
superpositions of many-particle states with entangled spin and trap degrees of
freedom, which remarkably are magnetic-field insensitive. Finally, we show that
the intersite tunneling may lead to a quantum phase transition described by an
effective quantum Ising model.",0803.0239v1
2009-04-30,Confluence of resonant laser excitation and bi-directional quantum dot nuclear spin polarization,"Resonant laser scattering along with photon correlation measurements have
established the atom-like character of quantum dots. Here, we present
measurements which challenge this identification for a wide range of
experimental parameters: the absorption lineshapes that we measure at magnetic
fields exceeding 1 Tesla indicate that the nuclear spins polarize by an amount
that ensures locking of the quantum dot resonances to the incident laser
frequency. In contrast to earlier experiments, this nuclear spin polarization
is bi-directional, allowing the electron+nuclear spin system to track the
changes in laser frequency dynamically on both sides of the quantum dot
resonance. Our measurements reveal that the confluence of the laser excitation
and nuclear spin polarization suppresses the fluctuations in the resonant
absorption signal. A master equation analysis shows narrowing of the nuclear
Overhauser field variance, pointing to potential applications in quantum
information processing.",0904.4767v1
2012-12-12,Feshbach Resonance in a Synthetic Non-Abelian Gauge Field,"We study the Feshbach resonance of spin-1/2 particles in the presence of a
uniform synthetic non-Abelian gauge field that produces spin orbit coupling
along with constant spin potentials. We develop a renormalizable quantum field
theory that includes the closed channel boson which engenders the Feshbach
resonance, in the presence of the gauge field. By a study of the scattering of
two particles in the presence of the gauge field, we show that the Feshbach
magnetic field, where the apparent low energy scattering length diverges,
depends on the conserved centre of mass momentum of the two particles. For high
symmetry gauge fields, such as the one which produces an isotropic Rashba spin
orbit coupling, we show that the system supports two bound states over a regime
of magnetic fields for a negative background scattering length and resonance
width comparable to the energy scale of the spin orbit coupling. We discuss the
consequences of these findings for the many body setting, and point out that a
broad resonance (width larger than spin orbit coupling energy scale) is most
favourable for the realization of the rashbon condensate.",1212.2858v1
2013-06-02,Spin relaxation mechanism in graphene: resonant scattering by magnetic impurities,"It is proposed that the observed small (100 ps) spin relaxation time in
graphene is due to resonant scattering by local magnetic moments. At
resonances, magnetic moments behave as spin hot spots: the spin-flip scattering
rates are as large as the spin-conserving ones, as long as the exchange
interaction is greater than the resonance width. Smearing of the resonance
peaks by the presence of electron-hole puddles gives quantitative agreement
with experiment, for about 1 ppm of local moments. While the local moments can
come from a variety of sources, we specifically focus on hydrogen adatoms. We
perform first-principles supercell calculations and introduce an effective
Hamiltonian to obtain realistic input parameters for our mechanism.",1306.0230v1
2015-02-26,Photoelectrical detection of electron spin resonance of nitrogen-vacancy centres in diamond,"The protocols for the control and readout of Nitrogen Vacancy (NV) centres
electron spins in diamond offer an advanced platform for quantum computation,
metrology and sensing. These protocols are based on the optical readout of
photons emitted from NV centres, which process is limited by the yield of
photons collection. Here we report on a novel principle for the detection of NV
centres magnetic resonance in diamond by directly monitoring spin-preserving
electron transitions through measurement of NV centre related photocurrent. The
demonstrated direct detection technique offers a sensitive way for the readout
of diamond NV sensors and diamond quantum devices on diamond chips. The
Photocurrent Detection of Magnetic Resonance (PDMR) scheme is based on the
detection of charge carriers promoted to the conduction band of diamond by the
two-photon ionization of NV- centres. Optical detection of magnetic resonance
(ODMR) and PDMR are compared, by performing both measurements simultaneously.
The minima detected in the measured photocurrent at resonant microwave
frequencies are attributed to the spin-dependent occupation probability of the
NV- ground state, originating from spin-selective non-radiative transitions.",1502.07551v1
2015-10-16,Randomized benchmarking of quantum gates implemented by electron spin resonance,"Spin systems controlled and probed by magnetic resonance have been valuable
for testing the ideas of quantum control and quantum error correction. This
paper introduces an X-band pulsed electron spin resonance spectrometer designed
for high-fidelity coherent control of electron spins, including a loop-gap
resonator for sub-millimeter sized samples with a control bandwidth ~ 40 MHz.
Universal control is achieved by a single-sideband upconversion technique with
an I-Q modulator and a 1.2 GS/s arbitrary waveform generator. A single qubit
randomized benchmarking protocol quantifies the average errors of Clifford
gates implemented by simple Gaussian pulses, using a sample of gamma-irradiated
quartz. Improvements in unitary gate fidelity are achieved through phase
transient correction and hardware optimization. A preparation pulse sequence
that selects spin packets in a narrowed distribution of static fields confirms
that inhomogeneous dephasing (1/T2*) is the dominant source of gate error. The
best average fidelity over the Clifford gates obtained here is 99.2%, which
serves as a benchmark to compare with other technologies.",1510.04779v3
2016-05-03,Proposal for a quantum delayed-choice experiment with a spin-mechanical setup,"We describe an experimentally feasible protocol for performing a variant of
the quantum delayed-choice experiment with massive objects. In this scheme, a
single nitrogen-vacancy (NV) center in diamond driven by microwave fields is
dispersively coupled to a massive mechanical resonator. A double-pulse Ramsey
interferometer can be implemented with the spin-mechanical setup, where the
second Ramsey microwave pulse drives the spin conditioned on the number states
of the resonator. The probability for finding the NV center in definite spin
states exhibits interference fringes when the mechanical resonator is prepared
in a specific number state. On the other hand, the interference is destroyed if
the mechanical resonator stays in some other number states. The wavelike and
particlelike behavior of the NV spin can be superposed by preparing the
mechanical resonator in a superposition of two distinct number states. Thus a
quantum version of Wheeler's delayed-choice experiment could be implemented,
allowing of fundamental tests of quantum mechanics on a macroscopic scale.",1605.00935v2
2019-05-10,Resonant orbits for a spinning particle in Kerr spacetime,"In the present article, we study the orbital resonance corresponds to an
extended object approximated up to the dipole order term in Kerr spacetime. We
start with the Mathisson-Papapetrou equations under the linear spin
approximation and primarily concentrate on two particular events. First, when
the orbits are nearly circular and executing a small oscillation about the
equatorial plane and second, a generic trajectory confined on the equatorial
plane. While in the first case, all the three fundamental frequencies, namely,
radial $\Omega_r$, angular $\Omega_{\theta}$, azimuthal $\Omega_{\phi}$ can be
commensurate with each others and give rise to the resonance phenomenon, the
later is only accompanied with the resonance between $\Omega_r$ and
$\Omega_{\phi}$ as we set $\theta=\pi/2$. We provide a detail derivation in
locating the prograde resonant orbits in either of these cases and also study
the role played by the spin of the black hole. The implications related to
spin-spin interactions between the object and black hole are also demonstrated.",1905.04061v2
2021-12-01,Pulse induced resonance with angular dependent total enhancement of multi-dimensional solid-state NMR correlation spectra,"We demonstrate a new resonance condition that obeys the relation
${\Delta}{\delta}=n{\nu}_{R}/2$, where ${\Delta}{\delta}$ is the chemical shift
difference between two homonuclear-coupled spins, ${\nu}_{R}$ is the
magic-angle spinning speed and $n$ is an integer. This modulation on the
rotational resonance recoupling condition is obtained by the application of
rotor-synchronous $^{1}$H pulses when at least one proton is dipolar-coupled to
one of the homonuclear-coupled spins. We suggest a new experimental scheme
entitled ""pulse induced resonance with angular dependent total enhancement""
(PIRATE) that can enhance proton-driven spin diffusion by the application of a
single $^{1}$H pulse every rotor period. Experimental evidence is demonstrated
on the two carbon spins of glycine and on the Y21M mutant of fd bacteriophage
virus. Numerical simulations reveal the existence of the resonances and report
on the important interactions governing this phenomena.",2112.00438v2
2023-03-22,"Temperature dependence of 7Li NMR relaxation rates in Li3InCl6, Li3YCl6, Li1.48Al0.48Ge1.52(PO4)3 and LiPS5Cl","Inorganic solid-state battery electrolytes show high ionic conductivities and
enable the fabrication of all solid-state batteries. In this work, we present
the temperature dependence of spin-lattice relaxation time (T1), spin-spin
relaxation time (T2), and resonance linewidth of the 7Li nuclear magnetic
resonance (NMR) for four solid-state battery electrolytes (Li3InCl6 (LIC),
Li3YCl6 (LYC), Li1.48Al0.48Ge1.52(PO4)3 (LAGP) and LiPS5Cl (LPSC)) from 173 K
to 403 K at a 7Li resonance frequency of 233 MHz, and from 253 K to 353 K at a
7Li resonance frequency of 291 MHz. Additionally, we measured the spin-lattice
relaxation rates at an effective 7Li resonance frequency of 133 kHz using a
spin-locking pulse sequence in the temperature range of 253 K to 353 K. In
LPSC, the 7Li NMR relaxation is consistent with the Bloembergen-Pound-Purcell
(BPP) theory of NMR relaxation of dipolar nuclei. In LIC, LYC and LAGP, the BPP
theory does not describe the NMR relaxation rates for the temperature range and
frequencies of our measurements. The presented NMR relaxation data assists in
providing a complete picture of Li diffusion in the four solid-state battery
electrolytes.",2303.12953v1
2024-04-11,"Three-flavor, Full Momentum Space Neutrino Spin Oscillations in Neutron Star Mergers","In the presence of anisotropic neutrino and antineutrino fluxes, the quantum
kinetic equations drive coherent oscillations in neutrino helicity, frequently
referred to as spin oscillations. These oscillations depend directly on the
absolute mass scale and Majorana phase, but are usually too transient to
produce important effects. In this paper we present a full momentum-space
analysis of Majorana neutrino spin oscillations in a snapshot of a
three-dimensional neutron star merger simulation. We find an interesting
angular dependence that allows for that resonant and adiabatic oscillations to
occur along specific directions in a large volume of the merger remnant. The
solid angle spanned by these directions is extremely narrow in general. We then
analyze spin transformation in the presence of flavor transformation by
characterizing how the effect's resonance and timescale change during a fast
flavor instability. For this analysis, we derive a generalized resonance
condition that poses a restrictive requirement for resonance to exist in any
flavor channel. We determine that spin oscillations at all locations in the
merger snapshot have a length scale that is too large for significant
oscillations to be expected even where there exist resonant and adiabatic
directions.",2404.08159v1
2013-05-17,Possible realization of an antiferromagnetic Griffiths phase in Ba[Fe(1-x)Mn(x)](2)As(2),"We investigate magnetic ordering in metallic Ba[Fe(1-x)Mn(x)](2)As(2) and
discuss the unusual magnetic phase, which was recently discovered for Mn
concentrations x > 10%. We argue that it can be understood as a Griffiths-type
phase that forms above the quantum critical point associated with the
suppression of the stripe-antiferromagnetic spin-density-wave (SDW) order in
BaFe2As2 by the randomly introduced localized Mn moments acting as strong
magnetic impurities. While the SDW transition at x = 0, 2.5% and 5% remains
equally sharp, in the x = 12% sample we observe an abrupt smearing of the
antiferromagnetic transition in temperature and a considerable suppression of
the spin gap in the magnetic excitation spectrum. According to our
muon-spin-relaxation, nuclear magnetic resonance and neutron-scattering data,
antiferromagnetically ordered rare regions start forming in the x = 12% sample
significantly above the N\'eel temperature of the parent compound. Upon
cooling, their volume grows continuously, leading to an increase in the
magnetic Bragg intensity and to the gradual opening of a partial spin gap in
the magnetic excitation spectrum. Using neutron Larmor diffraction, we also
demonstrate that the magnetically ordered volume is characterized by a finite
orthorhombic distortion, which could not be resolved in previous diffraction
studies most probably due to its coexistence with the tetragonal phase and a
microstrain-induced broadening of the Bragg reflections. We argue that
Ba[Fe(1-x)Mn(x)](2)As(2) could represent an interesting model spin-glass
system, in which localized magnetic moments are randomly embedded into a SDW
metal with Fermi surface nesting.",1305.4164v1
2020-03-28,Theory of the anomalous spin dynamics of spin-$\frac{1}{2}$ triangular lattice Heisenberg antiferromagnet and its application to Ba$_3$CoSb$_2$O$_9$,"Although it is well accepted that the spin-$\frac{1}{2}$ triangular lattice
Heisenberg antiferromagnet(TLHAF) has a long range ordered ground state, a
thorough understanding of its spin dynamics is still missing. While the linear
spin wave theory(LSWT) predicts three branches of magnon mode in the magnetic
Brillouin zone(MBZ), the 1/S expansion at the next order is found to break down
in a large portion of the MBZ centered around the M point, leaving the fate of
the magnon modes there undecided. Recent neutron scattering measurement on
Ba$_3$CoSb$_2$O$_9$, an ideal realization of the spin-$\frac{1}{2}$ TLHAF,
provides a surprising answer to this issue. Two, rather than three branches of
magnon mode are observed around the M point, whose dispersion are strongly
renormalized with respect to the LSWT prediction and exhibit pronounced
roton-like minimum at the M point. This is accompanied by a strong spin
fluctuation continuum at higher energy, inside which two strong and broad
spectral peaks of unknown origin are observed. In this work, we propose a
simple picture for these spectral anomalies by invoking the resonating valence
bond(RVB) physics in the description of the ground state of the system. We find
that the roton-like minimum in the magnon dispersion can be explained by the
coupling between the collective spin fluctuation and the continuum of Dirac
spinon excitation moving in a $\pi$-flux background. We also propose that the
two broad peaks in the continuum can be understood respectively as the Landau
damped third magnon mode and the Landau damped longitudinal mode. Such a
picture can be verified by studying the polarization character of the various
spectral features.",2003.12688v1
2022-11-30,Vortex-bound solitons in topological superfluid $^3$He,"The different superfluid phases of $^3$He are described by $p$-wave order
parameters that include anisotropy axes both in the orbital and spin spaces.
The anisotropy axes characterize the broken symmetries in these macroscopically
coherent quantum many-body systems. The systems' free energy has several
degenerate minima for certain orientations of the anisotropy axes. As a result,
spatial variation of the order parameter between two such regions, settled in
different energy minima, forms a topological soliton. Such solitons can
terminate in the bulk liquid, where the termination line forms a vortex with
trapped circulation of mass and spin superfluid currents. Here we discuss
possible soliton-vortex structures based on the symmetry and topology arguments
and focus on the three structures observed in experiments: solitons bounded by
spin-mass vortices in the B phase, solitons bounded by half-quantum vortices in
the polar and polar-distorted A phases, and the composite defect formed by a
half-quantum vortex, soliton and the Kibble-Lazarides-Shafi wall in the
polar-distorted B phase. The observations are based on nuclear magnetic
resonance (NMR) techniques and are of three types: first, solitons can form a
potential well for trapped spin waves, observed as an extra peak in the NMR
spectrum at shifted frequency; second, they can increase the relaxation rate of
the NMR spin precession; lastly, the soliton can present the boundary
conditions for the anisotropy axes in bulk, modifying the bulk NMR signal.
Owing to solitons' prominent NMR signatures and the ability to manipulate their
structure with external magnetic field, solitons have become an important tool
for probing and controlling the structure and dynamics of superfluid $^3$He, in
particular half-quantum vortices with core-bound Majorana modes.",2211.17117v2
2004-10-20,Upper-hybrid and electron-cyclotron waves in a laboratory magnetoplasma: weak spatial dispersion and parametric effects,"Radiation of short-wavelength plasma waves is studied in a cold (Te=0.5eV),
large (1.2m length, 70 cm diameter), uniform, Maxwellian laboratory
magnetoplasma in the upper-hybrid frequency range. Although the characteristic
parameter of spatial dispersion b2=VTe2/c2 is very small (b2<10-6), dispersion
characteristics of the upper hybrid plasma waves is found to be strongly
modified by the thermal motion of plasma electrons. Indeed, the resonance
cone-like dispersion of UH plasma waves has been observed only if the parameter
range satisfies simultaneously two inequalities: wc<w<2wc, wp<w<wuh. In this
parameter range, the maximal refractive index in the resonant directions has
been found to be limited by nmax~15; new UH mode with its dispersion determined
by conical refraction has been found in the vicinity of the upper hybrid
resonance (w=wuh). Wave dispersion at w<2wc, wp<w<wuh does not correspond to
the cold plasma approximation and is determined by thermal plasma waves
propagating along the ambient magnetic field. Special attention is given to the
wave propagation characteristics in the vicinity of the electron cyclotron
resonance. An interesting effect of reduced electron cyclotron damping has been
observed when two electromagnetic waves (w1=wc, w2=wc+Dw) propagate
simultaneously with Dw approximately equal to the lower hybrid frequency. This
effect can be explained as a three-wave parametric process, analogous to the
effect of electromagnetically induced transparency in three-level atomic
system. Reduced electron cyclotron damping is extensively studied as a function
of the beat frequency and the amplitude of the pump wave. Possible applications
of the observed effect in plasma physics and electronics are discussed.",0410177v1
2019-04-17,Excitation of interfacial waves via near---resonant surface---interfacial wave interactions,"We consider interactions between surface and interfacial waves in the two
layer system. Our approach is based on the Hamiltonian structure of the
equations of motion, and includes the general procedure for diagonalization of
the quadratic part of the Hamiltonian. Such diagonalization allows us to derive
the interaction crossection between surface and interfacial waves and to derive
the coupled kinetic equations describing spectral energy transfers in this
system. Our kinetic equation allows resonant and near resonant interactions. We
find that the energy transfers are dominated by the class III resonances of
\cite{Alam}. We apply our formalism to calculate the rate of growth for
interfacial waves for different values of the wind velocity. Using our kinetic
equation, we also consider the energy transfer from the wind generated surface
waves to interfacial waves for the case when the spectrum of the surface waves
is given by the JONSWAP spectrum and interfacial waves are initially absent. We
find that such energy transfer can occur along a timescale of hours; there is a
range of wind speeds for the most effective energy transfer at approximately
the wind speed corresponding to white capping of the sea. Furthermore,
interfacial waves oblique to the direction of the wind are also generated.",1904.08329v2
2022-06-21,"Bright, dark and breather soliton solutions of the generalized long-wave short-wave resonance interaction system","In this paper, a generalized long-wave short-wave resonance interaction
system, which describes the nonlinear interaction between a short-wave and a
long-wave in fluid dynamics, plasma physics and nonlinear optics, is
considered. Using the Hirota bilinear method, the general $N$-bright and
$N$-dark soliton solutions are deduced and their Gram determinant forms are
obtained. A special feature of the fundamental bright soliton solution is that,
in general, it behaves like the Korteweg-deVries soliton. However, under a
special condition, it also behaves akin to the nonlinear Schr\""{o}dinger
soliton when it loses the amplitude dependent velocity property. The
fundamental dark-soliton solution admits anti-dark, grey, and completely black
soliton profiles, in the short-wave component, depending on the choice of wave
parameters. On the other hand, a bright soliton like profile always occurs in
the long-wave component. The asymptotic analysis shows that both the bright and
dark solitons undergo an elastic collision with a finite phase shift. In
addition to these, by tuning the phase shift regime, we point out the existence
of resonance interactions among the bright solitons. Furthermore, under a
special velocity resonance condition, we bring out the various types of bright
and dark soliton bound states. Also, by fixing the phase factor and the system
parameter $\beta$, corresponding to the interaction between long and short wave
components, the different types of profiles associated with the obtained
breather solution are demonstrated.",2206.10159v1
2023-08-11,Electron resonant interaction with whistler-mode waves around the Earth's bow shock I: the probabilistic approach,"Adiabatic heating of solar wind electrons at the Earth's bow shock and its
foreshock region produces transversely anisotropic hot electrons that, in turn,
generate intense high-frequency whistler-mode waves. These waves are often
detected by spacecraft as narrow-band, electromagnetic emissions in the
frequency range of [0.1,0.5] of the local electron gyrofrequency. Resonant
interactions between these waves and electrons may cause electron acceleration
and pitch-angle scattering, which can be important for creating the electron
population that seeds shock drift acceleration. The high intensity and
coherence of the observed whistler-mode waves prohibit the use of quasi-linear
theory to describe their interaction with electrons. In this paper, we aim to
develop a new theoretical approach to describe this interaction, that
incorporates nonlinear resonant interactions, gradients of the background
density and magnetic field, and the fine structure of the waveforms that
usually consist of short, intense wave-packet trains. This is the first of two
accompanying papers. It outlines a probabilistic approach to describe the
wave-particle interaction. We demonstrate how the wave-packet size affects
electron nonlinear resonance at the bow shock and foreshock regions, and how to
evaluate electron distribution dynamics in such a system that is frequented by
short, intense whistler-mode wave-packets. In the second paper, this
probabilistic approach is merged with a mapping technique, which allows us to
model systems containing short and long wave-packets.",2308.05908v1
2000-01-21,Density Wave States of Non-Zero Angular Momentum,"We study the properties of states in which particle-hole pairs of non-zero
angular momentum condense. These states generalize charge- and
spin-density-wave states, in which s-wave particle-hole pairs condense. We show
that the p-wave spin-singlet state of this type has Peierls ordering, while the
d-wave spin-singlet state is the staggered flux state. We discuss model
Hamiltonians which favor p-wave and d-wave density wave order. There are
analogous orderings for pure spin models, which generalize spin-Peierls order.
The spin-triplet density wave states are accompanied by spin-1 Goldstone
bosons, but these excitations do not contribute to the spin-spin correlation
function. Hence, they must be detected with NQR or Raman scattering
experiments. Depending on the geometry and topology of the Fermi surface, these
states may admit gapless fermionic excitations. As the Fermi surface geometry
is changed, these excitations disappear at a transition which is third-order in
mean-field theory. The singlet d-wave and triplet p-wave density wave states
are separated from the corresponding superconducting states by zero-temperature
O(4)-symmetric critical points",0001303v1
2000-10-20,"Composite Spin Waves, Quasi-Particles and Low Temperature resistivity in Double Exchange Systems","We make a quantum description of the electron low temperature properties of
double exchange materials. In these systems there is a strong coupling between
the core spin and the carriers spin. This large coupling makes the low energy
spin waves to be a combination of ion and electron density spin waves. We study
the form and dispersion of these composite spin wave excitations. We also
analyze the spin up and down spectral functions of the temperature dependent
quasi-particles of this system. Finally we obtain that the thermally activated
composite spin waves renormalize the carriers effective mass and this gives
rise to a low temperature resistivity scaling as T ^{5/2}.",0010312v1
2009-10-09,Spin-waves in the $J_{1a}-J_{1b}-J_{2}$ orthorombic square-lattice Heisenberg models: Application to the iron pnictide materials,"Motivated by the observation of spatially anisotropic exchange constants in
the iron pnictide materials, we study the spin-wave spectra of the
$J_{1a}-J_{1b}-J_{2}$ Heisenberg models on a square-lattice with nearest
neighbor exchange $J_{1a}$ along x and $J_{1b}$ along y axis and a second
neighbor exchange $J_2$. We focus on the regime, where the spins order at
($\pi,0$), and compute the spectra by systematic expansions around the Ising
limit. We study both spin-half and spin-one Heisenberg models as well as a
range of parameters to cover various cases proposed for the iron pnictide
materials. The low-energy spectra have anisotropic spin-wave velocities and are
renormalized with respect to linear spin-wave theory by up to 20 percent,
depending on parameters. Extreme anisotropy, consisting of a ferromagnetic
$J_{1b}=- |J_F|$, is best distinguished from a weak anisotropy ($J_{1a}\approx
J_{1b}=J_1$, $J_2>J_1/2$) by the nature of the spin-waves near the wavevectors
($0,\pi$) or ($\pi,\pi$). The reported spectra for the pnictide material
CaFe$_2$As$_2$ clearly imply such an extreme anisotropy.",0910.1793v1
2010-09-25,Micro-Structured Ferromagnetic Tubes for Spin Wave Excitation,"Micron scale ferromagnetic tubes placed on the ends of ferromagnetic CoTaZr
spin waveguides are explored in order to enhance the excitation of Backward
Volume Magnetostatic Spin Waves. The tubes produce a closed magnetic circuit
about the signal line of the coplanar waveguide and are, at the same time,
magnetically contiguous with the spin waveguide. This results in a 10 fold
increase in spin wave amplitude. However, the tube geometry distorts the
magnetic field near the spin waveguide and relatively high biasing magnetic
fields are required to establish well defined spin waves. Only the lowest
(uniform) spin wave mode is excited.",1009.4986v1
2014-09-08,Dynamic control of spin wave spectra using spin-polarized currents,"We describe a method of controlling the spin wave spectra dynamically in a
uniform nanostripe waveguide through spin-polarized currents. A stable periodic
magnetization structure is observed when the current flows vertically through
the center of nanostripe waveguide. After being excited, the spin wave is
transmitted at the sides of the waveguide. Numerical simulations of spin-wave
transmission and dispersion curves reveal a single, pronounced band gap.
Moreover, the periodic magnetization structure can be turned on and off by the
spin-polarized current. The switching process from full rejection to full
transmission takes place within less than 3ns. Thus, this type magnonic
waveguide can be utilized for low-dissipation spin wave based filters.",1409.2421v2
2014-06-14,Electric-field coupling to spin waves in a centrosymmetric ferrite,"We experimentally demonstrate that the spin-orbit interaction can be utilized
for direct electric-field tuning of the propagation of spin waves in a
single-crystal yttrium iron garnet magnonic waveguide. Magnetoelectric coupling
not due to the spin-orbit interaction, and hence an order of magnitude weaker,
leads to electric-field modification of the spin-wave velocity for waveguide
geometries where the spin-orbit interaction will not contribute. A theory of
the phase shift, validated by the experiment data, shows that, in the exchange
spin wave regime, this electric tuning can have high efficiency. Our findings
point to an important avenue for manipulating spin waves and developing
electrically tunable magnonic devices.",1406.3675v1
2017-10-03,Spin-wave chirality and its manifestations in antiferromagnets,"As first demonstrated by Tang and Cohen in chiral optics, the asymmetry in
the rate of electromagnetic energy absorption between left and right
enantiomers is determined by an optical chirality density [1]. Here, we
demonstrate that this effect can exist in magnetic spin systems. By
constructing a formal analogy with electrodynamics, we show that in
antiferromagnets with broken chiral symmetry the asymmetry in local spin-wave
energy absorption is proportional to a spin-wave chirality density, which is a
direct counterpart of optical zilch. We propose that injection of a pure spin
current into an antiferromagnet may serve as a chiral symmetry breaking
mechanism, since its effect in the spin-wave approximation can be expressed in
terms of additional Lifshitz invariants. We use linear response theory to show
that the spin current induces a nonequilibrium spin-wave chirality density.",1710.01023v2
2020-05-22,Signatures of a liquid-crystal transition in spin-wave excitations of skyrmions,"Understanding the spin-wave excitations of chiral magnetic order, such as the
skyrmion crystal (SkX), is of fundamental interest to confirm such exotic
magnetic order. The SkX is realized by competing Dzyaloshinskii-Moriya and
ferromagnetic-exchange interactions with a magnetic field or anisotropy. Here
we compute the dynamical spin structure factor, using Monte Carlo and spin
dynamics simulations, extracting the spin-wave spectrum in the SkX, in the
vicinity of the paramagnet to SkX transition. Inside the SkX, we find six
spin-wave modes, which are supplemented by another mode originating from the
ferromagnetic background. Above the critical temperature $T_s$ for the skyrmion
crystallization, we find a diffusive regime, reminiscent of the
liquid-to-crystal transition, revealing that topological spin texture of
skyrmionic character starts to develop above $T_s$ as the precursor of the SkX.
We discuss the opportunities for the detection of the spin waves of the SkX
using inelastic-neutron-scattering experiments in manganite-iridate
heterostructures.",2005.11399v2
2021-06-05,Extraordinary transverse spin: Hidden vorticity of the energy flow and momentum distributions in propagating light fields,"Spatially inhomogeneous fields of electromagnetic guided modes exhibit a
complex of extraordinary dynamical properties such as the
polarization-dependent transverse momentum, helicity-independent transverse
spin, spin-associated non-reciprocity and unidirectional propagation, etc.
Recently, the remarkable relationship has been established between the spin and
propagation features of such fields, expressed through the spin-momentum
equations [Proc. Natl. Acad. Sci. 118 (2021) e2018816118] connecting the wave
spin with the curl of momentum. Here, the meaning, limitations and specific
forms of this correspondence are further investigated, involving the physically
transparent and consistent examples of paraxial light fields, plane-wave
superpositions and evanescent waves. The conclusion is inferred that the
spin-momentum equation is an attribute of guided waves with well defined
direction of propagation, and it unites the helicity-independent
""extraordinary"" transverse spin with the spatially-inhomogeneous longitudinal
field momentum (energy flow) density. Physical analogies with the layered
hydrodynamic flows and possible generalizations for other wave fields are
discussed. The results can be useful in optical trapping, manipulation and the
data processing techniques.",2106.02849v1
2022-04-27,Gravitational waves from small spin-up and spin-down events of neutron stars,"It was recently reported that there exists a population of ""glitch
candidates"" and ""anti-glitch candidates"" which are effectively small spin-ups
and spin-downs of a neutron star with magnitudes smaller than those seen in
typical glitches. The physical origin of these small events is not yet
understood. In this paper, we outline a model that can account for the changes
in spin, and crucially, is independently testable with gravitational wave
observations. In brief, the model posits that small spin-up/spin-down events
are caused by the excitation and decay of non-axisymmetric $f$-modes which
radiate angular momentum away in a burst-like way as gravitational waves. The
model takes the change in spin frequency as an input and outputs the initial
mode amplitude and the signal-to-noise ratio achievable from gravitational wave
detectors. We find that the model presented here will become falsifiable once
3rd generation gravitational wave detectors, like the Einstein Telescope and
Cosmic Explorer, begin taking data.",2204.12869v3
2022-06-23,Anisotropic magnon damping by zero-temperature quantum fluctuations in ferromagnetic CrGeTe$_3$,"Spin and lattice are two fundamental degrees of freedom in a solid, and their
fluctuations about the equilibrium values in a magnetic ordered crystalline
lattice form quasiparticles termed magnons (spin waves) and phonons (lattice
waves), respectively. In most materials with strong spin-lattice coupling
(SLC), the interaction of spin and lattice induces energy gaps in the spin wave
dispersion at the nominal intersections of magnon and phonon modes. Here we use
neutron scattering to show that in the two-dimensional (2D) van der Waals
honeycomb lattice ferromagnetic CrGeTe3, spin waves propagating within the 2D
plane exhibit an anomalous dispersion, damping, and break-down of quasiparticle
conservation, while magnons along the c axis behave as expected for a local
moment ferromagnet. These results indicate the presence of dynamical SLC
arising from the zero-temperature quantum fluctuations in CrGeTe3, suggesting
that the observed in-plane spin waves are mixed spin and lattice quasiparticles
fundamentally different from pure magnons and phonons.",2206.11962v1
2022-09-14,"Quantum Spin-Wave Theory for non-collinear Spin Structures, a Review","In this review, we trace the evolution of the quantum spin-wave theory
treating non-collinear spin configurations. Non-collinear spin configurations
are consequences of the frustration created by competing interactions. They
include simple chiral magnets due to competing nearest-neighbor (NN) and
next-NN interactions and systems with geometry frustration such as the
triangular antiferromagnet and the Kagom\'e lattice. We review here spin-wave
results of such systems and also systems with the Dzyaloshinskii-Moriya
interaction. Accent is put on these non-collinear ground states which have to
be calculated before applying any spin-wave theory to determine the spectrum of
the elementary excitations from the ground states. We mostly show results
obtained by the use of a Green's function method. These results include the
spin-wave dispersion relation and the magnetizations, layer by layer, as
functions of $T$ in 2D, 3D and thin films. Some new unpublished results are
also included. Technical details and discussion on the method are shown and
discussed.",2209.06771v1
2022-10-10,Charge distribution and spin textures in magic-angle twisted bilayer graphene,"We examine the coexisting spin and charge density waves as a possible ground
state of the magic-angle twisted bilayer graphene. When interactions are not
included, the spectrum of the material has 4 (8 if spin is taken into account)
almost flat almost degenerate bands. Interactions break down the degeneracy
forming an order parameter which is usually assumed to be a spin density wave
with a preset spin structure. Here we take into account a possible charge
density wave contribution to the order parameter, that is, inhomogeneous
distribution of the charge density within a twisted graphene supercell. We also
calculate self-consistently the spin structure of the order parameter. We find
that the density wave order is stable in the whole doping range from $-4$ to
$+4$ extra electrons per supercell. The spin texture changes from collinear at
zero doping to almost coplanar at finite doping. The density wave order shows
nematic distortion when we dope the system. We demonstrate that the local spin
magnetization is much stronger than the charge density variation, unless the
doping exceeds $3$ extra electrons or holes per supercell.",2210.04670v1
2010-02-26,Resonance clustering in wave turbulent regimes: Integrable dynamics,"Two fundamental facts of the modern wave turbulence theory are 1) existence
of power energy spectra in $k$-space, and 2) existence of ""gaps"" in this
spectra corresponding to the resonance clustering. Accordingly, three wave
turbulent regimes are singled out: \emph{kinetic}, described by wave kinetic
equations and power energy spectra; \emph{discrete}, characterized by resonance
clustering; and \emph{mesoscopic}, where both types of wave field time
evolution coexist. In this paper we study integrable dynamics of resonance
clusters appearing in discrete and mesoscopic wave turbulent regimes. Using a
novel method based on the notion of dynamical invariant we establish that some
of the frequently met clusters are integrable in quadratures for arbitrary
initial conditions and some others -- only for particular initial conditions.
We also identify chaotic behaviour in some cases. Physical implications of the
results obtained are discussed.",1002.4994v1
2016-04-10,Inherently Unstable Internal Gravity Waves due to Resonant Harmonic Generation,"Here we show that there exist internal gravity waves that are inherently
unstable, that is, they cannot exist in nature for a long time. The instability
mechanism is a one-way (irreversible) harmonic-generation resonance that
permanently transfers the energy of an internal wave to its higher harmonics.
We show that, in fact, there are countably infinite number of such unstable
waves. For the harmonic-generation resonance to take place, nonlinear terms in
the free surface boundary condition play a pivotal role, and the instability
does not obtain for a linearly-stratified fluid if a simplified boundary
condition such as rigid lid or linear form is employed. Harmonic-generation
resonance presented here also provides a mechanism for the transfer of the
energy of the internal waves to the higher-frequency part of the spectrum where
internal waves are more prone to breaking, hence losing energy to turbulence
and heat and contributing to oceanic mixing.",1604.02640v4
2021-10-05,Sparse metapiles for shear wave attenuation in half-spaces,"We show that shear waves traveling towards the surface of a half-space medium
can be attenuated via buried one-dimensional arrays of resonators -- here
called metapiles -- arranged according to sparse patterns around a site to be
isolated. Our focus is on shear waves approaching the surface along a direction
perpendicular to the surface itself. First, we illustrate the behavior of
metapiles, both experimentally and numerically, using 3D printed resonators
embedded in an acrylic plate. Then, via numerical simulations, we extend this
idea to the case study of an idealized soil half-space, and elucidate the
influence of various design parameters on wave attenuation. Results of this
work demonstrate that significant wave attenuation can be achieved by
installing sparse resonating piles around a selected site on the free surface
of the medium, rather than placing resonators directly underneath that same
site. This work might have implications in metamaterial-based wave attenuation
applications across scales.",2110.02202v2
2020-10-16,Topology of the Warm plasma dispersion relation at the second Harmonic Electron Cyclotron Resonance Layer,"The Warm Plasma Dispersion Relation, for waves in the electron cyclotron
resonance range of frequencies, can be cast into the form of a bi-quadratic
equation for $N_\perp$, where the coefficients are a function of $N_\perp^2$
and an iterative procedure is required to obtain a solution. However, this
iterative procedure is not well understood and fails to converge towards a
solution at the second harmonic resonance layer. In particular at higher
densities where the wave can couple to an electron Bernstein wave. This paper
focuses on a solution to the poor convergence of the iterative method, enabling
determination of the topology of the dispersion relation around the second
harmonic using a fully relativistic code for oblique waves. A feed-forward
controller is proposed with the ability to adjust the rotation of a step of
$N_\perp^2$ within the complex plane, while also limiting the step-size. It is
shown that implementation of the controller stabilizes unstable solutions,
while improving overall robustness of the iteration. This allows the evaluation
of the coupling between the fast extraordinary mode and electron Bernstein
waves at the second harmonic electron cyclotron resonance layer, for
non-perpendicularly propagating waves.",2010.08363v1
2022-05-01,Relativistic electron precipitation by EMIC waves: importance of nonlinear resonant effects,"Relativistic electron losses in Earth's radiation belts are usually
attributed to electron resonant scattering by electromagnetic waves. One of the
most important wave mode for such scattering is the electromagnetic ion
cyclotron (EMIC) mode. Within the quasi-linear diffusion framework, the
cyclotron resonance of relativistic electrons with EMIC waves results in very
fast electron precipitation to the atmosphere. However, wave intensities often
exceed the threshold for nonlinear resonant interaction, and such intense EMIC
waves have been shown to transport electrons away from the loss cone due to the
force bunching effect. In this study we investigate if this transport can block
electron precipitation. We combine test particle simulations, low-altitude
ELFIN observations of EMIC-driven electron precipitation, and ground-based EMIC
observations. Comparing simulations and observations, we show that, despite of
the low pitch-angle electrons being transported away from the loss cone, the
scattering at higher pitch angles results in the loss cone filling and electron
precipitation.",2205.00515v1
2023-02-05,Super-harmonically resonant swirling waves in longitudinally forced circular cylinders,"Resonant sloshing in circular cylinders was studied by Faltinsen et al.
(2016), whose theory was used to describe steady-state resonant waves due to
time-harmonic container's elliptic orbits. In the limit of longitudinal
container motions, a symmetry-breaking of the planar wave solution occurs, with
clockwise and anti-clockwise swirling equally likely. In addition to this
primary harmonic dynamics, previous experiments have unveiled that diverse
super-harmonic dynamics are observable far from primary resonances. Among
these, the so-called double-crest (DC) dynamics, first observed by Reclari et
al. (2014) for rotary sloshing, is particularly relevant, as its manifestation
is the most favored by the spatial structure of the external driving. Following
Bongarzone et al. (2022a), in this work we develop a weakly nonlinear (WNL)
analysis to describe the system response to super-harmonic longitudinal
forcing. The resulting system of amplitude equations predicts that a planar
wave symmetry-breaking via stable swirling may also occur under super-harmonic
excitation. This finding is confirmed by our experimental observations, which
identify three possible super-harmonic regimes, i.e. (i) stable planar DC
waves, (ii) irregular motion and (iii) stable swirling DC waves, whose
corresponding stability boundaries in the forcing frequency-amplitude plane
quantitatively match the present theoretical estimates.",2302.02443v1
1998-10-20,Unconventional ferromagnetic and spin-glass states of the reentrant spin glass Fe0.7Al0.3,"Spin excitations of single crystal Fe0.7Al0.3 were investigated over a wide
range in energy and reciprocal space with inelastic neutron scattering. In the
ferromagnetic phase, propagating spin wave modes become paramagnon-like
diffusive modes beyond a critical wave vector q0, indicating substantial
disorder in the long-range ordered state. In the spin glass phase, spin
dynamics is strongly q-dependent, suggesting remnant short-range spin
correlations. Quantitative model for S(energy,q) in the ``ferromagnetic'' phase
is determined.",9810265v2
2008-11-17,Dynamics in two-leg spin ladder with a four-spin cyclic interaction,"We study two-leg Heisenberg ladder with four-spin cyclic interaction using
the (dynamical) density-matrix renormalization group method. We demonstrate the
dependence of the low-lying excitations in the spin wave, staggered dimer
order, and scalar-chirality order structure factors on the four-spin cyclic
interaction. We find that the cyclic interaction enhances spin-spin
correlations with wave vector around momentum $(q_x,q_y)=(\frac{\pi}{2},0)$.
Also, the presence of long-range order in the staggered dimer and
scalar-chirality phases is confirmed by a $\delta$-function peak contribution
of the structure factors at energy $\omega=0$.",0811.2456v1
2011-03-20,The spin excitations of the block-antiferromagnetic K$_{0.8}$Fe$_{1.6}$Se$_2$,"We study the spin excitations of the newly discovered block-antiferromagnetic
state in K$_{0.8}$Fe$_{1.6}$Se$_2$ using an effective spin Hamiltonian
suggested in the literature. Interestingly in addition to the usual Goldstone
mode, there exists three other ""optical"" spin wave branches. These spin
excitations are the analog of ""optical phonons"" in crystals with more than one
atom per unit cell. We compute the spin wave corrected ordering moment and the
uniform spin susceptibilities.",1103.3884v1
2015-11-26,Spin textures and spin-wave excitations in doped Dirac-Weyl semimetals,"We study correlations and magnetic textures of localized spins, doped in
three-dimensional Dirac semimetals. An effective field theory for magnetic
moments is constructed by integrating out the fermionic degrees of freedom. The
spin correlation shows a strong anisotropy, originating from spin-momentum
locking of Dirac electrons, in addition to the conventional Heisenberg-like
ferromagnetic correlation. The anisotropic spin correlation allows
topologically nontrivial magnetic excitation textures such as a transient
hedgehog state, as well as the ferromagnetic ground state. The spin-wave
dispersion in ferromagnetic Weyl semimetal also becomes anisotropic, being less
dispersed perpendicular to the magnetization.",1511.08381v1
2014-11-05,Hybrid optical-electrical detection of donor electron spins with bound excitons in silicon,"Electrical detection of spins is an essential tool in understanding the
dynamics of spins in semiconductor devices, providing valuable insights for
applications ranging from optoelectronics and spintronics to quantum
information processing. For electron spins bound to shallow donors in silicon,
bulk electrically-detected magnetic resonance has relied on coupling to spin
readout partners such as paramagnetic defects or conduction electrons which
fundamentally limits spin coherence times. Here we demonstrate electrical
detection of phosphorus donor electron spin resonance by transport through a
silicon device, using optically-driven donor-bound exciton transitions. We use
this method to measure electron spin Rabi oscillations, and, by avoiding use of
an ancillary spin for readout, we are able to obtain long intrinsic electron
spin coherence times, limited only by the donor concentration. We go on to
experimentally address critical issues for adopting this scheme for single spin
measurement in silicon nanodevices, including the effects of strain, electric
fields, and non-resonant excitation. This lays the foundations for realising a
versatile readout method for single spin readout with relaxed magnetic field
and temperature requirements compared with spin-dependent tunneling.",1411.1324v1
2015-07-31,Electron spin resonance spectroscopy of small ensemble paramagnetic spins using a single nitrogen-vacancy center in diamond,"A nitrogen-vacancy (NV) center in diamond is a promising sensor for nanoscale
magnetic sensing. Here we report electron spin resonance (ESR) spectroscopy
using a single NV center in diamond. First, using a 230 GHz ESR spectrometer,
we performed ensemble ESR of a type-Ib sample crystal and identified a
substitutional single nitrogen impurity as a major paramagnetic center in the
sample crystal. Then, we carried out free-induction decay and spin echo
measurements of the single NV center to study static and dynamic properties of
nanoscale bath spins surrounding the NV center. We also measured ESR spectrum
of the bath spins using double electron-electron resonance spectroscopy with
the single NV center. The spectrum analysis of the NV-based ESR measurement
identified that the detected spins are the nitrogen impurity spins. The
experiment was also performed with several other single NV centers in the
diamond sample and demonstrated that the properties of the bath spins are
unique to the NV centers indicating the probe of spins in the microscopic
volume using NV-based ESR. Finally, we discussed the number of spins detected
by the NV-based ESR spectroscopy. By comparing the experimental result with
simulation, we estimated the number of the detected spins to be $\leq$ 50
spins.",1507.08744v2
1998-04-06,Three-dimensional waves generated at Lindblad resonances in thermally stratified disks,"We analyze the linear, 3D response to tidal forcing of a disk that is thin
and thermally stratified in the direction normal to the disk plane. We model
the vertical disk structure locally as a polytrope which represents a disk of
high optical depth. We solve the 3D gas-dynamic equations semi-analytically in
the neighborhood of a Lindblad resonance. These solutions match asymptotically
on to those valid away from resonances and provide solutions valid at all
radii. We obtain the following results. 1) A variety of waves are launched at
resonance. However, the f mode carries more than 95% of the torque exerted at
the resonance. 2) These 3D waves collectively transport exactly the amount of
angular momentum predicted by the 2D torque formula. 3) Near resonance, the f
mode occupies the full vertical extent of the disk. Away from resonance, the f
mode becomes confined near the surface of the disk, and, in the absence of
other dissipation mechanisms, damps via shocks. The radial length scale for
this process is roughly r_L/m (for resonant radius r_L and azimuthal wavenumber
m), independent of the disk thickness H. This wave channeling process is due to
the variations of physical quantities in r and is not due to wave refraction.
4) However, the inwardly propagating f mode launched from an m=2 inner Lindblad
resonance experiences relatively minor channeling.
  We conclude that for binary stars, tidally generated waves in highly
optically thick circumbinary disks are subject to strong nonlinear damping by
the channeling mechanism, while those in circumstellar accretion disks are
subject to weaker nonlinear effects. We also apply our results to waves excited
by young planets for which m is approximately r/H and conclude that the waves
are damped on the scale of a few H.",9804063v1
2004-10-11,The mechanism of Swing Absorption of fast magnetosonic waves in inhomogeneous media,"The recently suggested swing interaction between fast magnetosonic and
Alfv\'en waves (2002) is generalized to inhomogeneous media. We show that the
fast magnetosonic waves propagating across an applied non-uniform magnetic
field can parametrically amplify the Alfv\'en waves propagating along the field
through the periodical variation of the Alfv\'en speed. The resonant Alfv\'en
waves have half the frequency and the perpendicular velocity polarization of
the fast waves. The wavelengths of the resonant waves have different values
across the magnetic field, due to the inhomogeneity in the Alfv\'en speed.
Therefore, if the medium is bounded along the magnetic field, then the
harmonics of the Alfv\'en waves, which satisfy the condition for onset of a
standing pattern, have stronger growth rates. In these regions the fast
magnetosonic waves can be strongly 'absorbed', their energy going in
transversal Alfv\'en waves. We refer to this phenomenon as 'Swing Absorption'.
This mechanism can be of importance in various astrophysical situations.",0410277v1
2022-01-07,Formation of probability density waves and probability current density waves by excitation and decay of a doublet of quasistationary states of a three-barrier heterostructure upon scattering of gaussian wave packets,"A numerical-analytical simulation of scattering by a three-barrier
heterostructure of an electronic Gaussian wave packet, the spectral width of
which is on the order of the distance between the levels of the doublet of
quasi-stationary states, is carried out. It is shown that as a result of
scattering, damped waves of electron charge and current densities are formed
outside the double well, their characteristics are determined by the structure
of the initial wave packet and the poles of the scattering amplitudes. The
frequency of these waves is equal to the difference frequency of the doublet,
the wavenumber is the difference between the wave numbers of free motion of
electrons with resonant energies, and the speed of their propagation is the
ratio of these quantities. The system can go into the regime of repetition or
amplification of the emission of electron waves if a periodic resonant pumping
of the doublet population is provided by scattering of a series of coherent
wave packets.",2201.02288v1
2023-07-26,Beating resonance patterns and extreme power flux skewing in anisotropic elastic plates,"Elastic waves in anisotropic media can exhibit a power flux that is not
collinear with the wave vector. This has notable consequences for waves guided
in a plate. Through laser-ultrasonic experiments, we evidence remarkable
phenomena due to slow waves in a single crystal silicon wafer. Waves exhibiting
power flux orthogonal to their wave vector are identified. A pulsed line source
that excites these waves reveals a wave packet radiated parallel to the line.
Furthermore, there exist precisely eight plane waves with zero power flux.
These so-called zero-group-velocity modes are oriented along the crystal's
principal axes. Time acts as a filter in the wave vector domain that selects
these modes. Thus, a point source leads to beating resonance patterns with
moving nodal curves on the surface of the infinite plate. We observe this
pattern as it emerges naturally after a pulsed excitation.",2307.14259v2
2023-08-07,Nonlinear Landau resonant interaction between whistler waves and electrons: Excitation of electron acoustic waves,"Electron acoustic waves (EAWs), as well as electron-acoustic solitary
structures, play a crucial role in thermalization and acceleration of electron
populations in Earth's magnetosphere. These waves are often observed in
association with whistler-mode waves, but the detailed mechanism of EAW and
whistler wave coupling is not yet revealed. We investigate the excitation
mechanism of EAWs and their potential relation to whistler waves using
particle-in-cell simulations. Whistler waves are first excited by electrons
with a temperature anisotropy perpendicular to the background magnetic field.
Electrons trapped by these whistler waves through nonlinear Landau resonance
form localized field-aligned beams, which subsequently excite EAWs. By
comparing the growth rate of EAWs and the phase mixing rate of trapped electron
beams, we obtain the critical condition for EAW excitation, which is consistent
with our simulation results across a wide region in parameter space. These
results are expected to be useful in the interpretation of concurrent
observations of whistler-mode waves and nonlinear solitary structures, and may
also have important implications for investigation of cross-scale energy
transfer in the near-Earth space environment.",2308.03938v2
2015-05-12,Nonreciprocal spin wave propagation in chiral-lattice ferromagnets,"Spin current, i.e. the flow of spin angular momentum or magnetic moment, has
recently attracted much attention as the promising alternative for charge
current with better energy efficiency. Genuine spin current is generally
carried by the spin wave (propagating spin precession) in insulating
ferromagnets, and should hold the chiral symmetry when it propagates along the
spin direction. Here, we experimentally demonstrate that such a spin wave spin
current (SWSC) shows nonreciprocal propagation characters in a chiral-lattice
ferromagnet. This phenomenon originates from the interference of chirality
between the SWSC and crystal-lattice, which is mediated by the relativistic
spin-orbit interaction. The present finding enables the design of perfect spin
current diode, and highlights the importance of the chiral aspect in SWSC.",1505.02868v1
2019-01-24,Spin-Wave Theory for the Scalar Chiral Phase in the Multiple-Spin Exchange Model on a Triangular Lattice,"We study the effects of quantum fluctuations on a non-coplanar tetrahedral
spin structure, which has a scalar chiral order, in the spin-1/2 multiple-spin
exchange model with up to the six-spin exchange interactions on a triangular
lattice. We find that, in the linear spin-wave approximation, the tetrahedral
structure survives the quantum fluctuations because spin waves do not soften in
the whole parameter region of the tetrahedral-structure phase evaluated for the
classical system. In the quantum corrections to the ground-state energy,
sublattice magnetization, and scalar chirality, the effects of the quantum
fluctuations are small for the ferromagnetic nearest-neighbor interactions and
for the strong five-spin interactions. The six-spin interactions have little
effect on the quantum corrections in the tetrahedral-structure phase. This
calculation also corrects an error in the previously reported value of scalar
chirality for the spin-1/2 multiple-spin exchange model with up to the
four-spin exchange interactions.",1901.08198v1
2019-07-05,Theory for shift current of bosons: Photogalvanic spin current in ferrimagnetic and antiferromagnetic insulators,"We theoretically study the optical generation of dc spin current (i.e., a
spin-current solar cell) in ordered antiferromagnetic and ferrimagnetic
insulators, motivated by a recent study on the laser-driven spinon spin current
in noncentrosymmetric quantum spin chains [H. Ishizuka and M. Sato, Phys. Rev.
Lett. 122, 197702 (2019)]. Using a non-linear response theory for magnons, we
analyze the dc spin current generated by a linearly-polarized electromagnetic
wave (typically, terahertz or gigahertz waves). Considering noncentrosymmetric
two-sublattice magnets as an example, we find a finite dc spin current
conductivity at $T=0$, where no thermally-excited magnons exist; this is in
contrast to the case of the spinon spin current, in which the optical
transition of the Fermi degenerate spinons plays an essential role. We find
that the dc spin-current conductivity is insensitive to the Gilbert damping,
i.e., it may be viewed as a shift current carried by bosonic particles
(magnons). Our estimate shows that an electric-field intensity of
$E\sim10^4-10^6$ V/cm is sufficient for an observable spin current. Our theory
indicates that the linearly-polarized electromagnetic wave generally produces a
dc spin current in noncentrosymmetric magnetic insulators.",1907.02734v1
2022-09-26,Imprinting spatial helicity structure of vector vortex beam on spin texture in semiconductors,"We present the transfer of the spatially variant polarization of
topologically structured light to the spatial spin texture in a semiconductor
quantum well. The electron spin texture, which is a circular pattern with
repeating spin-up and spin-down states whose repetition rate is determined by
the topological charge, is directly excited by a vector vortex beam with a
spatial helicity structure. The generated spin texture efficiently evolves into
a helical spin wave pattern owing to the spin-orbit effective magnetic fields
in the persistent spin helix state by controlling the spatial wave number of
the excited spin mode. By tuning the repetition length and azimuthal angle, we
simultaneously generate helical spin waves with opposite phases by a single
beam.",2209.12496v1
2018-03-02,Neutron spin resonance in the 112-type iron-based superconductor,"We use inelastic neutron scattering to study the low-energy spin excitations
of 112-type iron pnictide Ca$_{0.82}$La$_{0.18}$Fe$_{0.96}$Ni$_{0.04}$As$_{2}$
with bulk superconductivity below $T_c=22$ K. A two-dimensional spin resonance
mode is found around $E=$ 11 meV, where the resonance energy is almost
temperature independent and linearly scales with $T_c$ along with other
iron-based superconductors. Polarized neutron analysis reveals the resonance is
nearly isotropic in spin space without any $L$ modulations. Due to the unique
monoclinic structure with additional zigzag arsenic chains, the As $4p$
orbitals contribute to a three-dimensional hole pocket around $\Gamma$ point
and an extra electron pocket at $X$ point. Our results suggest that the energy
and momentum distribution of spin resonance does not directly response to the
$k_z$ dependence of fermiology, and the spin resonance intrinsically is a
spin-1 mode from singlet-triplet excitations of the Cooper pairs in the case of
weak spin-orbital coupling.",1803.00779v2
2017-02-14,Quantum magnetic resonance microscopy,"Magnetic resonance spectroscopy is universally regarded as one of the most
important tools in chemical and bio-medical research. However, sensitivity
limitations typically restrict imaging resolution to length scales greater than
10 \mu m. Here we bring quantum control to the detection of chemical systems to
demonstrate high resolution electron spin imaging using the quantum properties
of an array of nitrogen-vacancy (NV) centres in diamond. Our quantum magnetic
resonance microscope selectively images electronic spin species by precisely
tuning a magnetic field to bring the quantum probes into resonance with the
external target spins. This provides diffraction limited spatial resolution of
the target spin species over a field of view of ~50x50 \mu m^2. We demonstrate
imaging and spectroscopy on aqueous Cu2+ ions over microscopic volumes (0.025
\mu m^3), with detection sensitivity at resonance of 104 spins/voxel, ~100
zeptomol (10^-19 mol). The ability to image, perform spectroscopy and
dynamically monitor spin-dependent redox reactions and transition metal
biochemistry at these scales opens up a new realm of nanoscopic electron spin
resonance and zepto-chemistry in the physical and life sciences.",1702.04418v1
2022-11-30,Fabrication and Characterization of Magnetic-Field-Resilient MoRe Superconducting Coplanar Waveguide Resonators,"Magnetic-field-resilient superconducting coplanar waveguide (SCPW) resonators
are essential for developing integrated quantum circuits of various qubits and
quantum memory devices. Molybdenum-Rhenium (MoRe), which is a disordered
superconducting alloy forming a highly transparent contact to the graphene and
carbon nanotubes (CNTs), would be a promising platform for realizing the
field-resilient SCPW resonators combined with graphene- and CNT-based
nano-hybrid qubits. We fabricated MoRe SCPW resonators and investigated their
microwave transmission characteristics with varying temperature and external
magnetic field. Our observations show that the thickness of MoRe film is a
critical parameter determining the lower critical field, kinetic inductance,
and characteristic impedance of the SCPW resonator, resulting in drastic
changes in the quality factor and the resonance frequency. As a result, we
obtained a maximum value of $Q_{i} > 10^{4}$ in parallel magnetic fields up to
$B_{||} = 0.15$ T for the 27-nm-thick MoRe resonator. Our experimental results
suggest that MoRe SCPW resonator would be useful for integrating nano-hybrid
spin or gatemon qubits and for developing spin-ensemble quantum memory devices.",2211.16948v1
2002-03-12,T-shaped spin filter with a ring resonator,"A planar ballistic structure is predicted to be highly effective in filtering
electron spin from an unpolarized source into two output fluxes with the
opposite and practically pure spin polarizations. The operability of the
proposed device relies on the peculiar spin-dependent transmission properties
of the T-shaped connector in the presence of the Rashba spin-orbit interaction
as well as the difference in the dynamic phase gains of the two alternative
paths around the ring resonator through upper and lower branches for even and
odd eigenmodes.",0203261v1
2005-12-30,Orbital Kondo effect and spin polarized transport through quantum dots,"The coherent spin dependent transport through a set of two capacitively
coupled quantum dots placed in a magnetic field is considered within the
equation of motion method. The magnetic field breaks the spin degeneracy. For
special choices of gate voltages the dot levels are tuned to resonance and the
orbital Kondo effect results. For different Zeemann splittings at the dots the
Kondo resonance can be formed for only one spin channel. In this case the
system operates as an efficient spin filter.",0512726v1
2000-09-25,Spin Relaxation Resonances Due to the Spin-Axis Interaction in Dense Rubidium and Cesium Vapor,"Resonances in the magnetic decoupling curves for the spin relaxation of dense
alkali-metal vapors prove that much of the relaxation is due to the spin-axis
interaction in triplet dimers. Initial estimates of the spin-axis coupling
coefficients for the dimers are 290 MHz for Rb; 2500 MHz for Cs.",0009072v1
2007-05-14,Cooling Torsional Nanomechanical Vibration by Spin-Orbit Interactions,"We propose and study a spin-orbit interaction based mechanism to actively
cool down the torsional vibration of a nanomechanical resonator made by
semiconductor materials. We show that the spin-orbit interactions of electrons
can induce a coherent coupling between the electron spins and the torsional
modes of nanomechanical vibration. This coherent coupling leads to an active
cooling for the torsional modes via the dynamical thermalization of the
resonator and the spin ensemble.",0705.1964v1
2007-05-15,Resonant Cooling of Nuclear Spins in Quantum Dots,"We propose to use the spin-blockade regime in double quantum dots to reduce
nuclear spin polarization fluctuations in analogy with optical Doppler cooling.
The Overhauser shift brings electron levels in and out of resonance, creating
feedback to suppress fluctuations. Coupling to the disordered nuclear spin
background is a major source of noise and dephasing in electron spin
measurements in such systems. Estimates indicate that a better than 10-fold
reduction of fluctuations is possible.",0705.2177v1
2007-07-12,The two dimensional spin and its resonance fringe,"Violation of Bell's Inequalities gives experimental evidence for the
existence of a spin 1/2 which has two simultaneous axes of spin quantization
rather than one. These couple to form a resonance state, called the spin
fringe, and this quantum effect is solely responsible for violation of Bell's
Inequalities within this model. The Bell states can be represented by products
of these spin states and leads to the intuitive concept that as entangled
states decompose they form biparticles that are not entangled. In EPR
coincidence experiments filter settings for both the Bell and CHSH forms of
Bell's Inequalities are rationalized in terms of the correlation between
biparticles.",0707.1763v2
2007-10-26,Spin-Dependent Scattering off Neutral Antimony Donors in 28-Si Field-Effect Transistors,"We report measurements of spin-dependent scattering of conduction electrons
by neutral donors in an accumulation-mode field-effect transistor formed in
isotopically enriched silicon. Spin-dependent scattering was detected using
electrically detected magnetic resonance where the spectra show resonant
changes in the source-drain voltage for conduction electrons and electrons
bound to donors. We discuss the utilization of spin-dependent scattering as a
mechanism for the readout of donor spin-states in silicon based quantum
computers.",0710.5164v2
2008-08-28,Electric excitation of spin resonance in antiferromagnetic conductors,"Antiferromagnetism couples electron spin to its orbital motion, thus allowing
excitation of electron-spin transitions by an ac electric rather than magnetic
field - with absorption, exceeding that of common electron spin resonance at
least by four orders of magnitude. In addition to potential applications in
spin electronics, this phenomenon may be used as a spectroscopy to study
antiferromagnetic materials of interest - from chromium to borocarbides,
cuprates, iron pnictides, and organic and heavy fermion conductors.",0808.3946v2
2008-09-24,Spin polarization control through resonant states in an Fe/GaAs Schottky barrier,"Spin polarization of the tunnel conductivity has been studied for Fe/GaAs
junctions with Schottky barriers. It is shown that band matching of resonant
interface states within the Schottky barrier defines the sign of spin
polarization of electrons transported through the barrier. The results account
very well for experimental results including the tunneling of photo-excited
electrons, and suggest that the spin polarization (from -100% to 100%) is
dependent on the Schottky barrier height. They also suggest that the sign of
the spin polarization can be controlled with a bias voltage.",0809.4094v1
2009-11-04,D'yakonov-Perel' spin relaxation in InSb/AlInSb quantum wells,"We investigate theoretically the D'yakonov-Perel' spin relaxation time by
solving the eight-band Kane model and Poisson equation self-consistently. Our
results show distinct behavior with the single-band model due to the anomalous
spin-orbit interactions in narrow band-gap semiconductors, and agree well with
the experiment values reported in recent experiment (K. L. Litvinenko, et al.,
New J. Phys. \textbf{8}, 49 (2006)). We find a strong resonant enhancement of
the spin relaxation time appears for spin align along [$1\bar{1}0$] at a
certain electron density at 4 K. This resonant peak is smeared out with
increasing the temperature.",0911.0855v1
2010-11-30,Diagonalization-free implementation of spin relaxation theory for large spin systems,"The Liouville space spin relaxation theory equations are reformulated in such
a way as to avoid the computationally expensive Hamiltonian diagonalization
step, replacing it by numerical evaluation of the integrals in the generalized
cumulant expansion. The resulting algorithm is particularly useful in the cases
where the static part of the Ha-miltonian is dominated by interactions other
than Zeeman (e.g. in quadrupolar reson-ance, low-field EPR and Spin Chemistry).
When used together with state space re-striction tools, the algorithm reported
is capable of computing full relaxation supero-perators for NMR systems with
more than 15 spins.",1012.0033v1
2010-12-16,Spin Hall Effect induced by resonant scattering on impurities in metals,"The Spin Hall Effect (SHE) is a promising way for transforming charge
currents into spin currents in spintronic devices. Large values of the Spin
Hall Angle, the characteristic parameter of the yield of this transformation,
have been recently found in noble metals doped with nonmagnetic impurities. We
show that this can be explained by resonant scattering off impurity states
split by the spin-orbit interaction. We apply our calculation to the
interpretation of experiments on copper doped with 5d impurities and we
describe the conditions to obtain the largest effects.",1012.3657v1
2013-02-19,The temperature dependence of quantum spin pumping generated using electron spin resonance with three-magnon splittings,"On the basis of the Schwinger-Keldysh formalism, we have closely investigated
the temperature dependence of quantum spin pumping by electron spin resonance.
We have clarified that three-magnon splittings excite non-zero modes of magnons
and characterize the temperature dependence of quantum spin pumping. Our
theoretical result qualitatively agrees with the experiment by Czeschka et al.
that the mixing conductance is little influenced by temperature [F. D. Czeschka
et al., Phys. Rev. Lett., 107, 046601 (2011)].",1302.4777v1
2013-04-12,Suppression of Spin-Exchange Relaxation Using Pulsed Parametric Resonance,"We demonstrate that spin-exchange dephasing of Larmor precession at
near-earth-scale fields is effectively eliminated by dressing the alkali-metal
atom spins in a sequence of AC-coupled 2-pi pulses, repeated at the Larmor
precession frequency. The contribution of spin-exchange collisions to the
spectroscopic line width is reduced by a factor of the duty cycle of the
pulses. We experimentally demonstrate resonant transverse pumping in magnetic
fields as high as 0.1 Gauss, present experimental measurements of the
suppressed spin-exchange relaxation, and show enhanced magnetometer response
relative to a light-narrowed scalar magnetometer.",1304.3737v1
2013-10-10,Effect of gate-driven spin resonance on the conductance of a one-dimensional quantum wire,"We consider quasiballistic electron transmission in a one-dimensional quantum
wire subject to both time-independent and periodic potentials of a finger gate
that results in a coordinate- and time-dependent Rashba-type spin-orbit
coupling. A spin-dependent conductance is calculated as a function of external
constant magnetic field, the electric field frequency, and the potential
strength. The results demonstrate the effect of the gate-driven electric dipole
spin resonance in a transport phenomenon such as spin-flip electron
transmission.",1310.2914v1
2013-11-22,A standard format and a graphical user interface for spin system specification,"We introduce a simple and general XML format for spin system description that
is the result of extensive consultations within Magnetic Resonance community
and unifies under one roof all major existing spin interaction specification
conventions. The format is human-readable, easy to edit and easy to parse using
standard XML libraries. We also describe a graphical user interface that was
designed to facilitate construction and visualization of complicated spin
systems. The interface is capable of generating input files for several popular
spin dynamics simulation packages.",1311.5770v1
2014-04-09,Current-induced spin torque resonance of magnetic insulators,"We formulate a theory of the AC spin Hall magnetoresistance (SMR) in a
bilayer system consisting of a magnetic insulator such as yttrium iron garnet
(YIG) and a heavy metal such as platinum (Pt). We derive expressions for the DC
voltage generation based on the drift-diffusion spin model and quantum
mechanical boundary condition at the interface that reveal a spin torque
ferromagnetic resonance (ST-FMR). We predict that ST-FMR experiments will
reveal valuable information on the current-induced magnetization dynamics of
magnetic insulators and AC spin Hall effect.",1404.2360v2
2016-05-10,Electron spin resonance from NV centers in diamonds levitating in an ion trap,"We report observations of the Electron Spin Resonance (ESR) of Nitrogen
Vacancy (NV) centers in diamonds that are levitating in an ion trap. Using a
needle Paul trap operating under ambient conditions, we demonstrate efficient
microwave driving of the electronic spin and show that the spin properties of
deposited diamond particles measured by the ESR are retained in the Paul trap.
We also exploit the ESR signal to monitor the rotation of levitating
monocrystals, a first step towards spin-controlled mechanical systems in
scattering-free traps.",1605.02953v2
2021-10-13,Signatures of electronic correlations and spin-susceptibility anisotropy in nuclear magnetic resonance,"We present a methodology for probing the details of electronic susceptibility
through minimally-invasive nuclear magnetic resonance techniques. Specifically,
we classify electron-mediated long-range interactions in an ensemble of nuclear
spins by revealing their effect on simple spin echo experiments. We find that
pulse strength and applied field orientation dependence of these spin echo
measurements resolves the spatial extent and anisotropy of electronic spin
susceptibility. This work provides an alternate explanation to NMR results in
superconducting and magnetically-ordered systems. The methodology has direct
applications for sensing and characterizing emergent electronic phases.",2110.06811v1
2008-06-26,Non-demolishing measurement of a spin qubit state via Fano resonance,"Fano resonances are proposed to perform a measurement of a spin state
(whether it is up or down) of a single electron in a quantum dot via a
spin-polarized current in an adjacent quantum wire. Rashba-like spin-orbit
interaction in a quantum dot prohibits spin-flip events (Kondo-like
phenomenon). That ensures the measurement to be non-demolishing.",0806.4339v2
2017-03-09,Off resonance coupling between a cavity mode and an ensemble of driven spins,"We study the interaction between a superconducting cavity and a spin
ensemble. The response of a cavity mode is monitored while simultaneously the
spins are driven at a frequency close to their Larmor frequency, which is tuned
to a value much higher than the cavity resonance. We experimentally find that
the effective damping rate of the cavity mode is shifted by the driven spins.
The measured shift in the damping rate is attributed to the retarded response
of the cavity mode to the driven spins. The experimental results are compared
with theoretical predictions and fair agreement is found.",1703.03311v1
2002-07-03,The Generalized Parton Distributions program at Jefferson Lab,"The Generalized Parton Distributions (GPD) have drawn a lot of interest from
the theoretical community since 1997, but also from the experimental community
and especially at Jefferson Lab. First, the results for Deeply Virtual Compton
Scattering (DVCS) at 4.2 GeV beam energy have recently been extracted from CLAS
data. The single spin asymmetry shows a remarkably clean sine wave despite the
rather low Q2 achievable at this energy. Two new dedicated DVCS experiments
using 6 GeV beam will run in 2003 and 2004 in Hall A and Hall B respectively.
Both experiments will yield very accurate results over a wide range of
kinematics, and allow for the first time a precise test of the factorization of
the DVCS process. Assuming the Bjorken regime is indeed reached, these
experiments will allow the extraction of linear combinations of GPD's and put
strong constraints on the available phenomenological models. Upon successful
completion of both experiments, a wider experimental program at 6 GeV can be
envisioned, using for instance Deuterium targets trying to nail down the
neutron and deuteron GPD's. In addition, resonances can be probed using
DeltaVCS where one produces a resonance in the final state. Finally, the 12 GeV
upgrade of Jefferson Lab extends the available kinematical range, and will
allow us to perform a complete, high precision GPD program using various
reactions among which, Deeply Virtual Meson Electroproduction (DVMP) and DVCS.",0207016v1
2005-10-17,"Tensor Ayy and vector Ay analyzing powers in the H(d,d')X and ^{12}C(d,d')X reactons at initial deuteron momenta of 9 GeV/c in the region of baryonic resonances excitation","The angular dependence of the tensor Ayy and vector Ay analyzing powers in
the inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen
and carbon have been measured. The range of measurements corresponds to the
baryonic resonance excitation with masses 2.2--2.6 GeV/c^2. The Ayy data being
in good agreement with the previous results demonstrate an approximate $t$
scaling up to -1.5 (GeV/c)^2. The large values of A_y show a significant role
of the spin-dependent part of the elementary amplitude of the NN->NN* reaction.
The results of the experiment are compared with model predictions of the
plane-wave impulse approximation.",0510050v1
2011-07-14,High temperature thermodynamics of strongly interacting s-wave and p-wave Fermi gases in a harmonic trap,"We theoretically investigate the high-temperature thermodynamics of a
strongly interacting trapped Fermi gas near either s-wave or p-wave Feshbach
resonances, using a second order quantum virial expansion. The second virial
coefficient is calculated based on the energy spectrum of two interacting
fermions in a harmonic trap. We consider both isotropic and anisotropic
harmonic potentials. For the two-fermion interaction, either s-wave or p-wave,
we use a pseudopotential parametrized by a scattering length and an effective
range. This turns out to be the simplest way of encoding the energy dependence
of the low-energy scattering amplitude or phase shift. This treatment of the
pseudopotential can be easily generalized to higher partial-wave interactions.
We discuss how the second virial coefficient and thermodynamics are affected by
the existence of these finite-range interaction effects. The virial expansion
result for a strongly interacting s -wave Fermi gas has already been proved
very useful. In the case of p-wave interactions, our results for the
high-temperature equation of state are applicable to future high-precision
thermodynamic measurements for a spin-polarized Fermi gas near a p-wave
Feshbach resonance.",1107.2740v1
2013-10-03,Nonequilibrium Statistical Mechanics of Systems with Long-Range Interactions: Ubiquity of Core-Halo Distributions,"Systems with long-range (LR) forces, for which the interaction potential
decays with the interparticle distance with an exponent smaller than the
dimensionality of the embedding space, remain an outstanding challenge to
statistical physics. The internal energy of such systems lacks extensivity and
additivity. Although the extensivity can be restored by scaling the interaction
potential with the number of particles, the non-additivity still remains. Lack
of additivity leads to inequivalence of statistical ensembles. Before relaxing
to thermodynamic equilibrium, isolated systems with LR forces become trapped in
out-of-equilibrium quasi-stationary state (qSS), the lifetime of which diverges
with the number of particles. Therefore, in thermodynamic limit LR systems will
not relax to equilibrium. The qSSs are attained through the process of
collisionless relaxation. Density oscillations lead to particle-wave
interactions and excitation of parametric resonances. The resonant particles
escape from the main cluster to form a tenuous halo. Simultaneously, this cools
down the core of the distribution and dampens out the oscillations. When all
the oscillations die out the ergodicity is broken and a qSS is born. In this
report, we will review a theory which allows us to quantitatively predict the
particle distribution in the qSS. The theory is applied to various LR
interacting systems, ranging from plasmas to self-gravitating clusters and
kinetic spin models.",1310.1078v1
2015-02-10,Two distinct kinetic regimes for the relaxation of light-induced superconductivity in La$_{1.675}$Eu$_{0.2}$Sr$_{0.125}$CuO$_{4}$,"We address the kinetic competition between charge striped order and
superconductivity in La$_{1.675}$Eu$_{0.2}$Sr$_{0.125}$CuO$_{4}$. Ultrafast
optical excitation is tuned to a mid-infrared vibrational resonance that
destroys charge order and promptly establishes transient coherent interlayer
coupling in this material. This effect is evidenced by the appearance of a
longitudinal plasma mode reminiscent of a Josephson plasma resonance. We find
that coherent interlayer coupling can be generated up to the charge order
transition $T_{CO} \approx$ 80 K, far above the equilibrium superconducting
transition temperature of any lanthanide cuprate. Two key observations are
extracted from the relaxation kinetics of the interlayer coupling. Firstly, the
plasma mode relaxes through a collapse of its coherence length and not its
density. Secondly, two distinct kinetic regimes are observed for this
relaxation, above and below spin order transition $T_{SO} =$ 25 K. Especially,
the temperature independent relaxation rate observed below $T_{SO}$ is
anomalous and suggests coexistence of superconductivity and stripes rather than
competition. Both observations support arguments that a low temperature
coherent stripe (or pair density wave) phase suppresses c-axis tunnelling by
disruptive interference rather than by depleting the condensate.",1502.03028v2
2016-04-04,Temperature dependent excitonic effects in the optical properties of single-layer MoS$_2$,"Temperature influences the performance of two-dimensional materials in
optoelectronic devices. Indeed, the optical characterization of these materials
is usually realized at room temperature. Nevertheless most {\it ab-initio}
studies are yet performed without including any temperature effect. As a
consequence, important features are thus overlooked, such as the relative
intensity of the excitonic peaks and their broadening, directly related to the
temperature and to the non-radiative exciton relaxation time. We present {\it
ab-initio} calculations of the optical response of single-layer MoS$_2$, a
prototype 2D material, as a function of temperature using density functional
theory and many-body perturbation theory. We compute the electron-phonon
interaction using the full spinorial wave functions, i.e., fully taking into
account effects of spin-orbit interaction. We find that bound excitons ($A$ and
$B$ peaks) and resonant excitons ($C$ peak) exhibit different behavior with
temperature, displaying different non-radiative linewidths. We conclude that
the inhomogeneous broadening of the absorption spectra is mainly due to
electron-phonon scattering mechanisms. Our calculations explain the
shortcomings of previous (zero-temperature) theoretical spectra and match well
with the experimental spectra acquired at room temperature. Moreover, we
disentangle the contributions of acoustic and optical phonon modes to the
quasi-particles and exciton linewidths. Our model also allows to identify which
phonon modes couple to each exciton state, useful for the interpretation of
resonant Raman scattering experiments.",1604.00943v1
2016-06-13,Characterization of oxygen defects in diamond by means of density functional theory calculations,"Point defects in diamond are of high interest as candidates for realizing
solid state quantum bits, bioimaging agents, or ultrasensitive electric or
magnetic field sensors. Various artificial diamond synthesis methods should
introduce oxygen contamination in diamond, however, the incorporation of oxygen
into diamond crystal and the nature of oxygen-related point defects are largely
unknown. Oxygen may be potentially interesting as a source of quantum bits or
it may interact with other point defects which are well established solid state
qubits. Here we employ plane-wave supercell calculations within density
functional theory, in order to characterize the electronic and magneto-optical
properties of various oxygen-related defects. Beside the trivial single
interstitial and substitutional oxygen defects we also consider their complexes
with vacancies and hydrogen atoms. We find that oxygen defects are mostly
electrically active and introduce highly correlated orbitals that pose a
challenge for density functional theory modeling. Nevertheless, we are able to
identify the fingerprints of substitutional oxygen defect, the oxygen-vacancy
and oxygen-vacancy-hydrogen complexes in the electron paramagnetic resonance
spectrum. We demonstrate that first principles calculations can predict the
motional averaging of the electron paramagnetic resonance spectrum of defects
that are subject to Jahn-Teller distortion. We show that the high-spin neutral
oxygen-vacancy defect exhibits very fast non-radiative decay from its optical
excited state that might hinder to apply it as a qubit.",1606.03859v2
2016-08-29,Sub-micrometer yttrium iron garnet LPE films with low ferromagnetic resonance losses,"Using liquid phase epitaxy (LPE) technique (111) yttrium iron garnet (YIG)
films with thicknesses of ~100 nm and surface roughnesses as low as 0.3 nm have
been grown as a basic material for spin-wave propagation experiments in
microstructured waveguides. The continuously strained films exhibit nearly
perfect crystallinity without significant mosaicity and with effective lattice
misfits of delta a(perpendicular)/a(substrate) ~10-4 and below. The
film/substrate interface is extremely sharp without broad interdiffusion layer
formation. All LPE films exhibit a nearly bulk-like saturation magnetization of
(1800+-20) Gs and an `easy cone' anisotropy type with extremely small in-plane
coercive fields <0.2 Oe. There is a rather weak in-plane magnetic anisotropy
with a pronounced six-fold symmetry observed for saturation field <1.5 Oe. No
significant out-of-plane anisotropy is observed, but a weak dependence of the
effective magnetization on the lattice misfit is detected. The narrowest
ferromagnetic resonance linewidth is determined to be 1.4 Oe @ 6.5 GHz which is
the lowest value reported so far for YIG films of 100 nm thicknesses and below.
The Gilbert damping coefficient for investigated LPE films is estimated to be
close to 1 x 10-4.",1608.08043v1
2018-01-31,Topological Flat Band and Parity-Time Symmetry in a Honeycomb Lattice of Coupled Resonant Optical Waveguides,"Two-dimensional (2D) coupled resonant optical waveguide (CROW), exhibiting
topological edge states, provides an efficient platform for designing
integrated topological photonic devices. In this paper, we propose an
experimentally feasible design of 2D honeycomb CROW photonic structure. The
characteristic optical system possesses two-fold and three-fold Dirac points at
different positions in the Brillouin zone. The effective gauge fields
implemented by the intrinsic pseudo-spin-orbit interaction open up
topologically nontrivial bandgaps through the Dirac points. Spatial lattice
geometries allow destructive wave interference, leading to a dispersionless,
nearly-flat energy band in the vicinity of the three-fold Dirac point in the
telecommunication frequency regime. This nontrivial nearly-flat band yields
topologically protected edge states. The pertinent physical effects brought
about due to non-Hermitian gain/loss medium into the honeycomb CROW device are
discussed. The generalized gain-loss lattice with parity-time symmetry
decouples the gain and the loss at opposite zigzag edges, leading to purely
gain or loss edge channels. Meanwhile, the gain and loss effects on the
armchair boundary cancel each other, giving rise to dissipationless edge states
in non-Hermitian optical systems. These characteristics underpin the
fundamental importance as well as the potential applications in various optical
devices such as polarizers, optical couplers, beam splitters and slow light
delay lines.",1801.10289v1
2018-05-11,Exciton states in monolayer MoSe2 and MoTe2 probed by upconversion spectroscopy,"Transitions metal dichalcogenides (TMDs) are direct semiconductors in the
atomic monolayer (ML) limit with fascinating optical and spin-valley
properties. The strong optical absorption of up to 20 % for a single ML is
governed by excitons, electron-hole pairs bound by Coulomb attraction. Excited
exciton states in MoSe$_2$ and MoTe$_2$ monolayers have so far been elusive due
to their low oscillator strength and strong inhomogeneous broadening. Here we
show that encapsulation in hexagonal boron nitride results in emission line
width of the A:1$s$ exciton below 1.5 meV and 3 meV in our MoSe$_2$ and
MoTe$_2$ monolayer samples, respectively. This allows us to investigate the
excited exciton states by photoluminescence upconversion spectroscopy for both
monolayer materials. The excitation laser is tuned into resonance with the
A:1$s$ transition and we observe emission of excited exciton states up to 200
meV above the laser energy. We demonstrate bias control of the efficiency of
this non-linear optical process. At the origin of upconversion our model
calculations suggest an exciton-exciton (Auger) scattering mechanism specific
to TMD MLs involving an excited conduction band thus generating high energy
excitons with small wave-vectors. The optical transitions are further
investigated by white light reflectivity, photoluminescence excitation and
resonant Raman scattering confirming their origin as excited excitonic states
in monolayer thin semiconductors.",1805.04440v1
2018-10-09,Determination of the pole position of the lightest hybrid meson candidate,"Mapping states with explicit gluonic degrees of freedom in the light sector
is a challenge, and has led to controversies in the past. In particular, the
experiments have reported two different hybrid candidates with spin-exotic
signature, pi1(1400) and pi1(1600), which couple separately to eta pi and eta'
pi. This picture is not compatible with recent Lattice QCD estimates for hybrid
states, nor with most phenomenological models. We consider the recent partial
wave analysis of the eta(') pi system by the COMPASS collaboration. We fit the
extracted intensities and phases with a coupled-channel amplitude that enforces
the unitarity and analyticity of the S-matrix. We provide a robust extraction
of a single exotic pi1 resonant pole, with mass and width 1564 +- 24 +- 86 MeV
and 492 +- 54 +- 102 MeV, which couples to both eta(') pi channels. We find no
evidence for a second exotic state. We also provide the resonance parameters of
the a2(1320) and a2'(1700).",1810.04171v2
2012-09-25,Resonating valence bond trial wave functions with both static and dynamically determined Marshall sign structure,"We construct energy-optimized resonating valence bond wavefunctions as a
means to sketch out the zero-temperature phase diagram of the square-lattice
quantum Heisenberg model with competing nearest- (J1) and
next-nearest-neighbour (J2) interactions. Our emphasis is not on achieving an
accurate representation of the magnetically disordered intermediate phase
(centred on a relative coupling g = J2/J1 ~ 1/2 and whose exact nature is still
controversial) but on exploring whether and how the Marshall sign structure
breaks down in the vicinity of the phase boundaries. Numerical evaluation of
two- and four-spin correlation functions is carried out stochastically using a
worm algorithm that has been modified to operate in either of two modes: one in
which the sublattice labelling is fixed beforehand and another in which the
worm manipulates the current labelling so as to sample various sign
conventions. Our results suggest that the disordered phase evolves continuously
out of the (pi,pi) Neel phase and largely inherits its Marshall sign structure;
on the other hand, the transition from the magnetically ordered (pi,0) phase is
strongly first order and involves an abrupt change in the sign structure and
spatial symmetry as the results of a level crossing.",1209.5743v2
2018-04-03,Kinetic frustration induced supersolid in the $S=1/2$ kagome lattice antiferromagnet in a magnetic field,"We examine instabilities of the plateau phases in the spin-1/2 kagome-lattice
antiferromagnet in an applied field by means of degenerate perturbation theory,
and find some emergent supersolid phases below the $m=5/9$ plateau. The wave
functions of the plateau phases in a magnetic field have the particular
construction based on the building blocks of resonating hexagons and their
surrounding sites. Magnon excitations on each of these blocks suffer from a
kinetic frustration effect, namely, they cannot hop easily to the others since
the hopping amplitudes through the two paths destructively cancel out with each
other. The itineracy is thus weakened, and the system is driven toward the
strong coupling regime, which together with the selected paths allowed in real
space bears a supersolid phase. This mechanism is contrary to that proposed in
lattice-Bose gases, where the strong competing interactions suppress with each
other, allowing a small kinetic energy scale to attain the itinerancy.
Eventually, we find a supersolid state in which the pattern of resonating
hexagons are preserved from the plateau crystal state and only one-third of the
originally polarized spins outside the hexagons dominantly join the superfluid
component, or equivalently, participate in the magnetization process.",1804.00789v3
2021-08-18,"Charge Order and Fluctuations in Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6+δ}$ Revealed by $^{63,65}$Cu-Nuclear Magnetic Resonance","The discovery of a magnetic-field-induced charge-density-wave (CDW) order in
the pseudogap state via nuclear magnetic resonance (NMR) studies has
highlighted the importance of ""charge"" in the physics of high
transition-temperature ($T_{\rm c}$) superconductivity in copper oxides
(cuprates). Herein, after briefly reviewing the progress achieved in the last
few years, we report new results of $^{63,65}$Cu-NMR measurements on the CDW
order and its fluctuation in the single-layered cuprate
Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6+\delta}$. The NMR spectrum under both in- and
out-of-plane magnetic fields above $ H $ = 10 T indicates that the CDW replaces
the antiferromagnetic order before superconductivity appears, but disappears
before superconductivity is optimized. We found that the CDW onset temperature
$T_{\rm CDW}$ scales with the pseudogap temperature $T^{\rm *}$. Comparison
between $^{63}$Cu and $^{65}$Cu NMR indicates that the spin-lattice relaxation
process is dominated by charge fluctuations in the doping regions where the CDW
appears as well as at the pseudogap end point ($T^*$ = 0). These results
suggest that charge orders and fluctuations exist in multiple doping regions
and over a quite wide temperature range.",2108.08150v1
2019-01-31,Do topology and ferromagnetism cooperate at the EuS/Bi$_2$Se$_3$ interface?,"We probe the local magnetic properties of interfaces between the insulating
ferromagnet EuS and the topological insulator Bi$_2$Se$_3$ using low energy
muon spin rotation (LE-$\mu$SR). We compare these to the interface between EuS
and the topologically trivial metal, titanium. Below the magnetic transition of
EuS, we detect strong local magnetic fields which extend several nm into the
adjacent layer and cause a complete depolarization of the muons. However, in
both Bi$_2$Se$_3$ and titanium we measure similar local magnetic fields,
implying that their origin is mostly independent of the topological properties
of the interface electronic states. In addition, we use resonant soft X-ray
angle resolved photoemission spectroscopy (SX-ARPES) to probe the electronic
band structure at the interface between EuS and Bi$_2$Se$_3$. By tuning the
photon energy to the Eu anti-resonance at the Eu $M_5$ pre-edge we are able to
detect the Bi$_2$Se$_3$ conduction band, through a protective Al$_2$O$_3$
capping layer and the EuS layer. Moreover, we observe a signature of an
interface-induced modification of the buried Bi$_2$Se$_3$ wave functions and/or
the presence of interface states.",1901.11347v1
2019-12-05,Iron-based superconductors: tales from the nuclei,"High-temperature superconductivity in Fe-based pnictides and chalcogenides
has been one of the most significant recent discoveries in condensed matter
physics and has attracted remarkable attention in the last decade. These
materials are characterized by a complex fermiology and, as a result, feature a
wide range of electronic properties as a function of different tuning
parameters such as chemical doping, temperature and pressure. Along the path
towards the comprehension of the physical mechanisms underlying this rich
phenomenology, NMR (nuclear magnetic resonance) and NQR (nuclear quadrupole
resonance) have played a role of capital importance that we review in this
work. In particular, we address how NMR has contributed to the current
understanding of the main regions of the electronic phase diagram of Fe-based
pnictides, that is, the -- sometimes coexisting -- antiferromagnetic
spin-density wave and superconducting states. We evidence the unique capability
of NMR as local-probe technique of investigating the effect of quenched
disorder and chemical impurities. Then, we review the NMR signatures of
low-frequency fluctuations associated with the development of electronic
nematicity as well as with the motion of superconducting flux lines. Finally,
we discuss recent contributions of NMR and NQR which evidence an intrinsically
inhomogeneous electronic charge distribution as well as an orbitally-selective
behaviour.",1912.02603v1
2021-03-04,Observation of the near-threshold intruder $0^-$ resonance in $^{12}$Be,"A resonant state at $3.21^{+0.12}_{-0.04}$\,MeV, located just above the
one-neutron separation threshold, was observed for the first time in $^{12}$Be
from the $^{11}$Be\,$(d,p)^{12}$Be one-neutron transfer reaction in inverse
kinematics. This state is assigned a spin-parity of $0^-$, according to the
distorted-wave Born approximation (DWBA) and decay-width analysis. Gamow
coupled-channel (GCC) and Gamow shell-model (GSM) calculations show the
importance of the continuum-coupling, which dramatically influences the
excitation energy and ordering of low-lying states. Various exotic structures
associated with cross-shell intruding configurations in $^{12}$Be and in its
isotonic nucleus $^{11}$Li are comparably discussed.",2103.02785v1
2024-02-01,"Element-specific and high-bandwidth ferromagnetic resonance spectroscopy with a coherent, extreme ultraviolet (EUV) source","We developed and applied a tabletop, ultrafast, high-harmonic generation
(HHG) source to measure the element-specific ferromagnetic resonance (FMR) in
ultra-thin magnetic alloys and multilayers on an opaque Si substrate. We
demonstrate a continuous wave bandwidth of 62 GHz, with promise to extend to
100 GHz or higher. This laboratory-scale instrument detects the FMR using
ultrafast, extreme ultraviolet (EUV) light, with photon energies spanning the
M-edges of most relevant magnetic elements. An RF frequency comb generator is
used to produce a microwave excitation that is intrinsically synchronized to
the EUV pulses with a timing jitter of 1.4 ps or better. We apply this system
to measure the dynamics in a multilayer system as well as Ni-Fe and Co-Fe
alloys. Since this instrument operates in reflection-mode, it is a milestone
toward measuring and imaging the dynamics of the magnetic state and spin
transport of active devices on arbitrary and opaque substrates. The higher
bandwidth also enables measurements of materials with high magnetic anisotropy,
as well as ferrimagnets, antiferromagnets, and short-wavelength (high
wavevector) spinwaves in nanostructures or nanodevices. Furthermore, the
coherence and short wavelength of the EUV will enable extending these studies
using dynamic nanoscale lensless imaging techniques such as coherent
diffractive imaging, ptychography, and holography.",2402.00783v1
2024-03-05,"Note: Harnessing Tellurium Nanoparticles in the Digital Realm Plasmon Resonance, in the Context of Brewster's Angle and the Drude Model for Fake News Adsorption in Incomplete Information Games","This note explores the innovative application of soliton theory and plasmonic
phenomena in modeling user behavior and engagement within digital health
platforms. By introducing the concept of soliton solutions, we present a novel
approach to understanding stable patterns of health improvement behaviors over
time. Additionally, we delve into the role of tellurium nanoparticles and their
plasmonic properties in adsorbing fake news, thereby influencing user
interactions and engagement levels. Through a theoretical framework that
combines nonlinear dynamics with the unique characteristics of tellurium
nanoparticles, we aim to provide new insights into the dynamics of user
engagement in digital health environments. Our analysis highlights the
potential of soliton theory in capturing the complex, nonlinear dynamics of
user behavior, while the application of plasmonic phenomena offers a promising
avenue for enhancing the sensitivity and effectiveness of digital health
platforms. This research ventures into an uncharted territory where optical
phenomena such as Brewster's Angle and Snell's Law, along with the concept of
spin solitons, are metaphorically applied to address the challenge of fake news
dissemination. By exploring the analogy between light refraction, reflection,
and the propagation of information in digital platforms, we unveil a novel
perspective on how the 'angle' at which information is presented can
significantly affect its acceptance and spread. Additionally, we propose the
use of tellurium nanoparticles to manage 'information waves' through mechanisms
akin to plasmonic resonance and soliton dynamics. This theoretical exploration
aims to bridge the gap between physical sciences and digital communication,
offering insights into the development of strategies for mitigating
misinformation.",2403.03239v1
1995-09-04,Spin-wave condensation and quantum melting of long-range antiferromagnetic order in t-J model,"Ground state wave function of two-dimensional t-J model is found at doping
close to half filling. It is shown that the condensation of Cooper pairs
(superconducting pairing of mobile holes) and the condensation of spin-waves
into spin-liquid state are closely connected. The effective spectrum of $S=1$
excitations, spin-wave gap pseudo-gap $\Delta_M$, magnetic correlation length
$\xi_M$, and static magnetic formfactor $S_M(\bf q)$ are calculated.",9509011v1
1995-09-13,Spin-wave excitation spectra and spectral weights in square lattice antiferromagnets,"Using a recently developed method for calculating series expansions of the
excitation spectra of quantum lattice models, we obtain the spin-wave spectra
for square lattice, $S=1/2$ Heisenberg-Ising antiferromagnets. The calculated
spin-wave spectrum for the Heisenberg model is close to but noticeably
different from a uniformly renormalized classical (large-$S$) spectrum with the
renormalization for the spin-wave velocity of approximately $1.18$. The
relative weights of the single-magnon and multi-magnon contributions to neutron
scattering spectra are obtained for wavevectors throughout the Brillouin zone.",9509077v1
1995-11-17,The incoherent part of the spin-wave polarization operator in the t-J model,"A calculation of the spin-wave polarization operator is very important for
the analysis of the magnetic structure of high temperature superconductors. We
analyze the significance of the incoherent part of the spin-wave polarization
operator within the framework of the t-J model. This part is calculated
analytically for small doping with logarithmic accuracy. We conclude that the
incoherent part of the spin-wave polarization operator is negligible in
comparison with the coherent part.",9511087v2
1996-02-08,Isotropic Spin Wave Theory of Short-Range Magnetic Order,"We present an isotropic spin wave (ISW) theory of short-range order in
Heisenberg magnets, and apply it to square lattice S=1/2 and S=1
antiferromagnets. Our theory has three identical (isotropic) spin wave modes,
whereas the conventional spin wave theory has two transverse and one
longitudinal mode. We calculate temperature dependences of various
thermodynamic observables analytically and find good (several per cent)
agreement with independently obtained numerical results in a broad temperature
range.",9602044v1
1997-12-23,The edge theory of ferromagnetic quantum Hall states,"We propose an effective low-energy theory for ferromagnetic Hall states. It
describes the charge degrees of freedom, on the edge, by a (1 + 1) dimensional
chiral boson theory, and the spin degrees of freedom by the (2 + 1)dimensional
quantum ferromagnet theory in the spin-wave approximation. The usual chiral
boson theory for spinless electrons is modified to include the charge degrees
of freedom with spin. Our total, bulk plus edge, effective action is gauge
invariant and we find a generalized ""chiral anomaly"" in this case. We describe
two, charged and neutral, sets of edge spin-wave solutions. The spreading of
these waves is much larger than the one for the charge (edge) waves and they
have linear dispersion relations.",9712279v1
1999-07-12,"Dynamics of the Compact, Ferromagnetic ν=1 Edge","We consider the edge dynamics of a compact, fully spin polarized state at
filling factor $\nu=1$. We show that there are two sets of collective
excitations localized near the edge: the much studied, gapless, edge
magnetoplasmon but also an additional edge spin wave that splits off below the
bulk spin wave continuum. We show that both of these excitations can soften at
finite wave-vectors as the potential confining the system is softened, thereby
leading to edge reconstruction by spin texture or charge density wave
formation. We note that a commonly employed model of the edge confining
potential is non-generic in that it systematically underestimates the texturing
instability.",9907175v1
2000-10-16,Spin waves in ultrathin ferromagnetic overlayers,"The influence of a non-magnetic metallic substrate on the spin wave
excitations in ultrathin ferromagnetic overlayers is investigated for different
crystalline orientations. We show that spin wave dumping in these systems occur
due to the tunneling of holes from the substrate into the overlayer, and that
the spin wave energies may be considerably affected by the exchange coupling
mediated by the substrate.",0010215v1
2002-03-19,Spin-wave spectrum of copper metaborate in the commensurate phase 10K<T<21K,"We have investigated the spin-wave spectrum of copper metaborate,
CuB$_2$O$_4$, by means of inelastic neutron scattering in the commensurate
magnetic phase. We have found two branches of spin-wave excitations associated
with the two magnetic sublattices Cu(A) and Cu(B), respectively. In the
temperature regime $10K \le T \le 21K$, where only the Cu(A) magnetic moments
are ordered, the interaction between the two sublattices is found to be
negligible. With this approximation we have determined the `easy plane'
exchange parameters of the Cu(A) subsystem within standard spin-wave theory.",0203369v1
2005-06-14,Spin-wave softening and Hund's coupling in ferromagnetic manganites,"Using one-orbital model of hole-doped manganites, we show with the help of
Holstein-Primakov transformation that finite Hund's coupling is responsible for
the spin-wave softening in the ferromagnetic $B$-phase manganites. We obtain an
analytical result for the spin-wave spectrum for $\JH\gg t$. In the limit of
infinte Hund's coupling, the spectrum is the conventional nearest-neighbor
Heisenberg ferromagnetic spin-wave. The $o(t/\JH)$-order correction is negative
and thus accounts for the softening near the zone boundary.",0506321v1
2005-08-25,Interactions of spin waves with a magnetic vortex,"We have investigated azimuthal spin-wave modes in magnetic vortex structures
using time-resolved Kerr microscopy. Spatially resolved phase and amplitude
spectra of ferromagnetic disks with diameters from 5 $\mu$m down to 500 nm
reveal that the lowest order azimuthal spin wave mode splits into a doublet as
the disk size decreases. We demonstrate that the splitting is due to the
coupling between spin waves and the gyrotropic motion of the vortex core.",0508597v1
2006-04-13,Spin-wave instability for parallel pumping in ferromagnetic thin films under oblique field,"Spin-wave instability for parallel pumping is studied theoretically. The
spin-wave instability threshold is calculated in ferromagnetic thin films under
oblique field which has an oblique angle to the film plane. The butterfly curve
of the threshold usually has a cusp at a certain value of the static external
field. While the static field value of the cusp point varies as the oblique
angle changes, the general properties of the butterfly curve show little
noteworthy change. For very thin films, however, multiple cusps of the
butterfly curve can appear due to different standing spin-wave modes, which
indicate a novel feature for thin films under oblique field.",0604329v1
2007-01-19,Excited states of quantum many-body interacting systems: A variational coupled-cluster description,"We extend recently proposed variational coupled-cluster method to describe
excitation states of quantum many-body interacting systems. We discuss, in
general terms, both quasiparticle excitations and quasiparticle-density-wave
excitations (collective modes). In application to quantum antiferromagnets, we
reproduce the well-known spin-wave excitations, i.e. quasiparticle magnons of
spin $\pm 1$. In addition, we obtain new, spin-zero magnon-density-wave
excitations which has been missing in Anserson's spin-wave theory. Implications
of these new collective modes are discussed.",0701482v1
2007-11-29,Realization of XNOR and NAND spin-wave logic gates,"We demonstrate the functionality of spin-wave logic XNOR and NAND gates based
on a Mach-Zehnder type interferometer which has arms implemented as sections of
ferrite film spin-wave waveguides. Logical input signals are applied to the
gates by varying either the phase or the amplitude of the spin waves in the
interferometer arms. This phase or amplitude variation is produced by Oersted
fields of dc current pulses through conductors placed on the surface of the
magnetic films.",0711.4720v1
2008-01-19,Electrical control of magnon propagation in multiferroic BiFeO3 films,"The spin wave spectra of multiferroic BiFeO3 films is calculated using a
phenomenological Landau theory that includes magnetostatic effects. The lowest
frequency magnon dispersion is shown to be quite sensitive to the angle between
spin wave propagation vector and the Neel moment. Since electrical switching of
the Neel moment has recently been demonstrated in this material, the
sensitivity of the magnon dispersion permits direct electrical switching of
spin wave propagation. This effect can be used to construct spin wave logical
gates without current pulses, potentially allowing reduced power dissipation
per logical operation.",0801.3012v1
2008-03-26,Unusual spin-wave population in nickel after femtosecond laser pulse excitation,"The spin-wave relaxation mechanisms after intense laser excitation in
ferromagnetic nickel films are investigated with all-optical pump-probe
experiments. Uniform precession (Kittel mode), Damon-Eshbach surface modes and
perpendicular standing spin waves can be identified by their dispersion f(H).
However, different to other ferromagnets f(H) deviates from the expected
behavior. Namely, a mode discontinuity is observed, that can be attributed to a
non-linear process. Above a critical field the power spectrum reveals a
redistribution of the energy within the spin-wave spectrum populated.",0803.3686v2
2009-01-14,Interface coupling properties and reflection of bulk spin waves from biaxial multilayer ferromagnetic media,"The reflection coefficient of bulk spin waves from multilayer ferromagnetic
structure with periodically modulated parameters of exchange interaction,
uniaxial and rhombic magnetic anisotropy and saturation magnetization is
calculated with a non-ideal coupling between layers. The strong dependence of
spin-wave reflection coefficient on frequency, magnetic field and parameter of
interfacial coupling is revealed. It allows changing the reflection intensity
from 0 to 1 by changing either only external magnetic field value or frequency.
The proposed model of boundary conditions gives the opportunity to take into
account the quality of interfaces when studying the reflection processes of
spin waves in multilayer structures.",0901.2012v1
2011-03-06,Spin-wave energy dispersion of a frustrated spin-1/2 Heisenberg antiferromagnet on a stacked square lattice,"Effects of interlayer coupling and spatial anisotropy on spin-wave excitation
spectra of a three-dimensional spatially anisotropic, frustrated spin-$\half$
Heisenberg antiferromagnet (HAFM) is investigated for the two ordered phases
using second-order spin-wave expansion. We show that the second-order
corrections to the spin-wave energies are significant and find that the energy
spectra of the three-dimensional HAFM shares similar qualitative features with
the energy spectra of the two-dimensional HAFM on a square lattice. We also
discuss the features that can provide experimental measures for the strength of
the interlayer coupling, spatial anisotropy parameter, and magnetic
frustration.",1103.1155v1
2011-03-29,Spin waves in the block checkerboard antiferromagnetic phase,"Motivated by the discovery of new family 122 iron-based superconductors, we
present the theoretical results on the ground state phase diagram, spin wave
and dynamic structure factor of the extended $J_{1}-J_{2}$ Heisenberg model. In
the reasonable physical parameter region of $K_{2}Fe_{4}Se_{5}$, we fi{}nd the
block checkerboard antiferromagnetic order phase is stable. There are two
acoustic branches and six optical branches spin wave in the block checkerboard
antiferromagnetic phase, which has analytic expression in the high symmetry
points. To compare the further neutron scattering experiments, we discuss the
saddlepoint structure in the magnetic excitation spectrum and calculate the
predicted inelastic neutron scattering pattern based on linear spin wave
theory.",1103.5521v1
2011-11-16,Spatial distribution of spin-wave modes in cylindrical nanowires of finite aspect ratio,"The spin wave modes of cylindrical nanowires of moderate diameter-to-length
ratio are investigated in this article. Based on three dimensional simulations
and analytical calculations we determine the spatial structure of the modes. We
show that standing spin waves and localized edge modes form the discrete
spectrum of the nanowires. Using a simple analytical model we infer an extended
dispersion relation for spin waves in cylinders. Considering the variation of
the demagnetizing (internal) field we show that the localized dipole-exchange
modes at the edges are always present.",1111.3838v1
2012-04-20,Spin Versus Charge Density Wave Order in Graphene-like Systems,"A variational technique is used to study sublattice symmetry breaking by
strong on-site and nearest neighbor interactions in graphene. When interactions
are strong enough to break sublattice symmetry, and with relative strengths
characteristic of graphene, a charge density wave Mott insulator is favored
over the spin density wave condensates. In the spin density wave condensate we
find that introduction of a staggered on-site energy (quasiparticle mass) leads
to a splitting of the fermi velocities and mass gaps of the quasiparticle spin
states.",1204.4531v2
2012-05-21,Emergence of spatial spin-wave correlations in a cold atomic gas,"Rydberg spin waves are optically excited in a quasi-one-dimensional atomic
sample of Rb atoms. Pair-wise spin-wave correlations are observed by a
spatially selective transfer of the quantum state onto a light field and
photoelectric correlation measurements of the light. The correlations are
interpreted in terms of the dephasing of multiply-excited spin waves by
long-range Rydberg interactions.",1205.4708v2
2012-08-09,Spin waves interference from rising and falling edges of electrical pulses,"The authors have investigated the effect of the electrical pulse width of
input excitations on the generated spin waves in a NiFe strip using pulse
inductive time domain measurements. The authors have shown that the spin waves
resulting from the rising- and the falling-edges of input excitation pulses
interfere either constructively or destructively, and have provided conditions
for obtaining spin wave packets with maximum intensity at different bias
conditions.",1208.1836v1
2014-04-29,On conformal higher spin wave operators,"We analyze free conformal higher spin actions and the corresponding wave
operators in arbitrary even dimensions and backgrounds. We show that the wave
operators do not factorize in general, and identify the Weyl tensor and its
derivatives as the obstruction to factorization. We give a manifestly
factorized form for them on (A)dS backgrounds for arbitrary spin and on
Einstein backgrounds for spin 2. We are also able to fix the conformal wave
operator in d=4 for s=3 up to linear order in the Riemann tensor on generic
Bach-flat backgrounds.",1404.7452v2
2014-10-13,Vortex gyration mediated by spin waves driven by an out-of-plane oscillating magnetic field,"In this letter we address the vortex core dynamics involved in gyration
excitation and damping change by out-of-plane oscillating magnetic fields. When
the vortex core is at rest under the effect of in-plane bias magnetic fields,
the spin waves excited by the perpendicular magnetic field can induce obvious
vortex gyration. When simultaneously excite spin waves and vortex gyrotropic
motion, the gyration damping changes. Analysis of the system energy allows us
to explain the origin of the spin-wave-mediated vortex gyration.",1410.3230v1
2017-05-03,Controlling Chiral Domain Walls in Antiferromagnets Using Spin-Wave Helicity,"In antiferromagnets, the Dzyaloshinskii-Moriya interaction lifts the
degeneracy of left- and right-circularly polarized spin waves. This
relativistic coupling increases the efficiency of spin-wave-induced domain wall
motion and leads to higher drift velocities. We show that in biaxial
antiferromagnets, the spin-wave helicity controls both the direction and
magnitude of the magnonic force on chiral domain walls. By contrast, in
uniaxial antiferromagnets, the magnonic force is propulsive with a helicity
dependent strength.",1705.01572v2
2003-12-31,Excitation of Spin Waves in Superconducting Ferromagnets,"This Letter presents a theoretical analysis of propagation of spin waves in a
superconducting ferromagnet. The surface impedance was calculated for the case
when the magnetization is normal to the sample surface. We found the
frequencies at which the impedance and the power absorption have singularities
related to the spin wave propagation, and determined the form of these
singularities. With a suitable choice of parameters, there is a frequency
interval in which two propagating spin waves of the same circular polarization
are generated, one of them having a negative group velocity.",0312720v1
2017-03-09,Spin-wave excitations in the SDW state of iron pnictides: a comparison between the roles of interaction parameters,"We investigate the role of Hund's coupling in the spin-wave excitations of
the ($\pi, 0$) ordered magnetic state within a five-orbital tight-binding model
for iron pnictides. To differentiate between the roles of intraorbital Coulomb
interaction and Hund's coupling, we focus on the self-consistently obtained
mean-field SDW state with a fixed magnetic moment obtained by using different
sets of interaction parameters. We find that the Hund's coupling is crucial for
the description of various experimentally observed characteristics of the
spin-wave excitations including the anisotropy, energy-dependent behavior, and
spin-wave spectral weight distribution.",1703.03228v2
2020-05-06,Angular momentum conservation in counter-propagating vectorially structured light,"It is well-known that electric spin angular momentum and electric orbital
angular momentum are conserved under paraxial propagation of travelling waves
in free-space. Here we study the electric and magnetic angular momentum in
counter-propagating waves and show both theoretically and experimentally that
neither component alone is conserved except in special cases. We attribute this
non-conservation to spin-spin and orbit-orbit coupling between the electric and
magnetic fields. This work generalises previous findings based on travelling
waves, explains the apparent spin-orbit coupling in counter-propagating
paraxial light, and broadens our understanding of angular momentum conservation
in arbitrary structured light waves.",2005.02739v1
2020-12-23,Analytic description of spin waves in dipolar/octupolar pyrochlore magnets,"We derive analytic forms for spin waves in pyrochlore magnets with
dipolar-octupolar interactions, such as ${\rm Nd}_2{\rm Zr}_2{\rm O}_7$. We
obtain full knowledge of the diagonalized magnonic Hamiltonian within the
linear spin wave approximation. We also consider the effect of a ""breathing
mode"" as a perturbation of this system. The breathing mode lifts the degeneracy
of the upper band of the spin wave dispersion along the direction $X\to W$ in
$k$-space.",2012.12500v1
2021-03-05,Universal spin wave damping in magnetic Weyl semimetals,"We analyze the decay of spin waves into Stoner excitations in magnetic Weyl
semimetals. The lifetime of a mode is found to have a universal dependence on
its frequency and momentum, and on a few parameters that characterize the
relativistic Weyl spectrum. At the same time, Gilbert damping by Weyl electrons
is absent. The decay rate of spin waves is calculated perturbatively using the
s-d model of itinerant Weyl or Dirac electrons coupled to local moments. We
show that many details of the Weyl spectrum, such as the momentum-space
locations, dispersions and sizes of the Weyl Fermi pockets, can be deduced
indirectly by probing the spin waves of local moments using inelastic neutron
scattering.",2103.03885v1
2021-12-29,Spin Wave Propagation through Antiferromagnet/Ferromagnet Interface,"We study the problem of controlling spin waves propagation through an
antiferromagnet/ferromagnet interface via tuning material parameters. It is
done by introducing the degree of sublattice noncompensation of antiferromagnet
(DSNA), which is a physical characteristic of finite-thickness interfaces. The
DSNA value can be varied by designing interfaces with a particular disorder or
curvilinear geometry. We describe a spin-wave propagation through any designed
antiferromagnet/ferromagnet interface considering a variable DSNA and
appropriate boundary conditions. As a result, we calculate the physical
transmittance and reflectance of the spin waves as a function of frequency and
show how to control them via the exchange parameters tuning.",2112.14583v1
2022-03-17,Electron Wave Spin in a Quantum Well,"The particle-wave duality of the electron poses a principle question of
whether the spin is a property of the particle or the wave. In this paper, the
wave nature of the spin is studied for an electron inside a two-dimensional
quantum well. By solving the exact $4-$spinor eigen solution to the Dirac
equation, we show that a stable circulating total current density exists inside
the well with a donut shaped topography. A spin value is modified by the
confining geometry of the well. Our analysis also shows that a free electron
Gaussian wavepacket is unstable and experiences quick decoherence.",2203.09437v2
2004-06-02,Observation of single defect relaxation in a freely suspended nano resonator,"Relaxation of single defects in a nanometer sized resonator is observed by
coupling surface acoustic waves to a freely suspended beam. The surface waves
act on the resonator as driving forces being able to modify the internal
friction in the beam. In analogy to classical experiments on internal friction
in macroscopic samples, we perform frequency, amplitude, and temperature
dependent experiments on the nano resonator and find a scenario which is
consistent with the observation of single defect relaxation.",0406056v1
1999-09-23,Partial Wave Analysis of $J/ψ\toγ(π^+π^-π^+π^-)$,"BES data on $J/\psi \to \gamma (\pi^{+} \pi^{-} \pi^{+} \pi^{-})$ have been
analyzed into partial waves. We fit with resonances having $J^{PC}=2^{++}$ at
1275 MeV, $0^{++}$ at 1500 MeV, $2^{++}$ at 1565 MeV, $0^{++}$ at 1740 MeV,
$2^{++}$ at 1940 MeV and $0^{++}$ at 2104 MeV, plus a broad $0^-$ component.
The $0^{++}$ resonances decay dominantly to $\sigma\sigma$, while $2^{++}$
resonances in the high mass region decay mainly to $f_2(1270)\sigma$ and
$\sigma\sigma$; $2^{++}$ resonances from the low mass region decay dominantly
to $\rho\rho$.",9909040v2
2007-01-31,Exact and quasi-resonances in discrete water-wave turbulence,"The structure of discrete resonances in water-wave turbulence is studied. It
is shown that the number of exact 4-wave resonances is huge (hundreds million)
even in comparatively small spectral domain when both scale and angle energy
transport is taken into account. It is also shown that angle transport can
contribute inexplicitly to scale transport. Restrictions for quasi-resonances
to start are written out. The general approach can be applied directly to
mesoscopic systems encountered in condensed matter (quantum dots), medical
physics, etc.",0701077v3
1999-01-01,Quantum slow motion,"We simulate the center of mass motion of cold atoms in a standing, amplitude
modulated, laser field as an example of a system that has a classical mixed
phase-space. We show a simple model to explain the momentum distribution of the
atoms taken after any distinct number of modulation cycles. The peaks
corresponding to a classical resonance move towards smaller velocities in
comparison to the velocities of the classical resonances. We explain this by
showing that, for a wave packet on the classical resonances, we can replace the
complicated dynamics in the quantum Liouville equation in phase-space by the
classical dynamics in a modified potential. Therefore we can describe the
quantum mechanical motion of a wave packet on a classical resonance by a purely
classical motion.",9901001v1
2008-02-18,Resonance sum rules from large $N_C$ and partial wave dispersive analysis,"Combining large $N_C$ techniques and partial wave dispersion theory to
analyze the $\pi\pi$ scattering, without relying on any explicit resonance
lagrangian, some interesting results are derived: (a) a general KSRF relation
including the scalar meson contribution; (b) a new relation between resonance
couplings, with which we have made an intensive analysis in several specific
models; (c) low energy constants in chiral perturbation theory related with
$\pi\pi$ scattering in terms of the mass and decay width of resonances.",0802.2530v1
2009-12-14,Magnetic Faraday rotation in lossy photonic structures,"Magnetic Faraday rotation is widely used in optics and MW. In uniform
magneto-optical materials, this effect is very weak. One way to enhance it is
to incorporate the magnetic material into a high-Q optical resonator. One
problem with magneto-optical resonators is that along with Faraday rotation,
the absorption and linear birefringence can also increase dramatically,
compromising the device performance. Another problem is strong ellipticity of
the output light. We discuss how the above problems can be addressed in the
cases of optical microcavities and a slow wave resonators. We show that a slow
wave resonator has a fundamental advantage when it comes to Faraday rotation
enhancement in lossy magnetic materials.",0912.2612v1
2010-10-28,Gas lasers with wave-chaotic resonators,"Semiclassical multimode laser theory is extended to gas lasers with open
two-dimensional resonators of arbitrary shape. The Doppler frequency shift of
the linear-gain coefficient leads to an additional linear coupling between the
modes, which, however, is shown to be negligible. The nonlinear laser equations
simplify in the special case of wave-chaotic resonators. In the single-mode
regime, the intensity of a chaotic laser, as a function of the mode frequency,
displays a local minimum at the frequency of the atomic transition. The width
of the minimum scales with the inhomogeneous linewidth, in contrast to the Lamb
dip in uniaxial resonators whose width is given by the homogeneous linewidth.",1010.5985v1
2011-06-08,Surface Acoustic Wave Frequency Comb,"We report on realization of an efficient triply-resonant coupling between two
long lived optical modes and a high frequency surface acoustic wave (SAW) mode
of the same monolithic crystalline whispering gallery mode resonator. The
coupling results in an opto-mechanical oscillation and generation of a
monochromatic SAW. A strong nonlinear interaction of this mechanical mode with
other equidistant SAW modes leads to mechanical hyper-parametric oscillation
and generation of a SAW pulse train and associated frequency comb in the
resonator. We visualized the comb observing the modulation of the modulated
light escaping the resonator.",1106.1477v1
2012-05-31,Variation of Longitudinal Plasma Wavelength under Irradiation and Double Resonance in Coupled Josephson Junctions,"The effect of electromagnetic wave irradiation on the phase dynamics of
intrinsic Josephson junctions in high temperature superconductors is
investigated. We predict three novel effects by variation of the radiation
amplitude and frequency: changing of the longitudinal plasma wavelength at
parametric resonance; double resonance of the Josephson oscillations with
radiation and longitudinal plasma wave; charging of superconducting layers in
the current interval corresponding to the Shapiro step. The ""bump"" structure in
IVC recently observed experimentally is demonstrated. We also observe ragged
Shapiro steps at double resonance.",1205.6923v1
2014-12-07,Experimental Demonstration of Non-Resonant Hyperlens in the Visible Range,"A metamaterial hyperlens offers a unique solution to overcome the diffraction
limit by transforming evanescent waves responsible for imaging subwavelength
features of an object into propagating waves. However, the first realizations
of optical hyperlenses were limited by a narrow working bandwidth and
significant resonance-induced loss. Here, we report the first experimental
demonstration of a non-resonant waveguide-coupled hyperlens operating in the
visible wavelength range. A detailed investigation of various materials systems
proves that a radial fan-shaped configuration is superior to the concentric
layer-based configuration in that it relies on non-resonant negative dielectric
response, and, as a result, enables broadband and low-loss performance in the
visible range.",1412.2361v1
2018-09-14,Four-wave mixing in a silicon microring resonator using a self-pumping geometry,"We report on four-wave mixing in a silicon microring resonator using a
self-pumping scheme instead of an external laser. The ring resonator is
inserted in an external-loop cavity with a fibered semiconductor amplifier as a
source of gain. The silicon microring acts as a filter and we observe lasing in
one of the microring's resonances. We study correlations between signal and
idler generated beams using a Joint Spectral Density experiment.",1809.05323v1
2018-09-27,Identifying resonances with wave-packet dynamics,"A new method for the study of resonant behavior - using wave-packet dynamics
- is presented, based on the powerful window operator technique. The method is
illustrated and quantified by application to the astrophysically-important
example of low-energy $^{12}$C + $^{12}$C collisions. For this selected,
potential model test case, the technique is shown to provide both resonance
energies and widths in agreement with alternative methods, such as
complex-energy scattering-matrix pole searches and scattering phase-shift
analyses. The method has a more general capability to study resonance phenomena
across disciplines, that involve particles temporarily trapped by potential
pockets.",1809.10517v2
2019-05-12,Stereodynamical control of a quantum scattering resonance in cold molecular collisions,"Cold collisions of light molecules are often dominated by a single partial
wave resonance. For the rotational quenching of HD(v=1,j=2) by collisions with
ground state para-H2, the process is dominated by a single L=2 partial wave
resonance centered around 0.1 K. Here, we show that this resonance can be
switched on or off simply by appropriate alignment of the HD rotational angular
momentum relative to the initial velocity vector, thereby enabling complete
control of the collision outcome.",1905.04765v1
2017-03-28,Resonance State Wave Functions of $^{15}$Be using Supersymmetric Quantum Mechanics,"The theoretical procedure of supersymmetric quantum mechanics is adopted to
generate the resonance state wave functions of the unbound nucleus $^{15}$Be.
In this framework, we used a density dependent M3Y microscopic potential and
arrived at the energy and width of the 1.8 MeV (5/2$^+$) resonance state. We
did not find any other nearby resonances for $^{15}$Be. It becomes apparent
that the present framework is a powerful tool to theoretically complement the
increasingly important accelerator based experiments with unbound nuclei.",1703.09448v2
2019-12-04,Explicit form of the effective evolution equation for the randomly forced Schrödinger equation with quadratic nonlinearity,"An effective equation describes a weakly nonlinear wave field evolution
governed by nonlinear dispersive PDEs \emph{via} the set of its resonances in
an arbitrary big but finite domain in the Fourier space. We consider the
Schr\""{o}dinger equation with quadratic nonlinearity including small external
random forcing/dissipation.
  An effective equation is deduced explicitly for each case of monomial
quadratic nonlinearities $ u^2, \, \bar{u}u, \, \bar{u}^2$ and the sets of
resonance clusters are studied. In particular, we demonstrate that the
nonlinearity $\bar{u}^2$ generates no 3-wave resonances and its effective
equation is degenerate while in two other cases the sets of resonances are not
empty. Possible implications for wave turbulence theory are briefly discussed.",1912.02289v1
2024-01-17,A Distributed Magnetostatic Resonator,"This work reports the design, fabrication, and characterization of
coupling-enhanced magnetostatic forward volume wave resonators with significant
spur suppression. The fabrication is based on surface micro-machining of
yttrium iron garnet (YIG) film on a gadolinium gallium garnet (GGG) substrate
with thick gold transducers. A distributed resonator is used to excite forward
volume waves in YIG to realize a frequency dependent coupling boost. Fabricated
devices at 18 GHz and 7 GHz show coupling coefficients as high as 13$\%$ and
quality factors above 1000. Higher-order magnetostatic mode suppression is
experimentally demonstrated through a combination of transducer and YIG
geometry design. An edge-coupling filter topology is proposed and simulated
which utilizes this novel distributed magnetostatic resonator.",2401.08911v1
2001-04-28,Origin of enhanced dynamic nuclear polarization and all-optical nuclear magnetic resonance in GaAs quantum wells,"Time-resolved optical measurements of electron-spin dynamics in a (110) GaAs
quantum well are used to study the consequences of a strongly anisotropic
electron g-tensor, and the origin of previously discovered all-optical nuclear
magnetic resonance. All components of the g-tensor are measured, and a strong
anisotropy even along the in-plane directions is found. The amplitudes of the
spin signal allow the study of the spatial directions of the injected spin and
its precession axis. Surprisingly efficient dynamic nuclear polarization in a
geometry where the electron spins are injected almost transverse to the applied
magnetic field is attributed to an enhanced non-precessing electron spin
component. The small absolute value of the electron g-factor combined with
efficient nuclear spin polarization leads to large nuclear fields that dominate
electron spin precession at low temperatures. These effects allow for sensitive
detection of all-optical nuclear magnetic resonance induced by periodically
excited quantum-well electrons. The mechanism of previously observed Delta m =
2 transitions is investigated and found to be attributable to electric
quadrupole coupling, whereas Delta m = 1 transitions show signatures of both
quadrupole and electron-spin induced magnetic dipole coupling.",0104564v1
2006-11-08,Control of electron spin and orbital resonance in quantum dots through spin-orbit interactions,"Influence of resonant oscillating electromagnetic field on a single electron
in coupled lateral quantum dots in the presence of phonon-induced relaxation
and decoherence is investigated. Using symmetry arguments it is shown that spin
and orbital resonance can be efficiently controlled by spin-orbit interactions.
The control is possible due to the strong sensitivity of Rabi frequency to the
dot configuration (orientation of the dot and a static magnetic field) as a
result of the anisotropy of the spin-orbit interactions. The so called easy
passage configuration is shown to be particularly suitable for magnetic
manipulation of spin qubits, ensuring long spin relaxation time and protecting
the spin qubit from electric field disturbances accompanying on-chip
manipulations.",0611228v2
2007-04-12,Detection of single electron spin resonance in a double quantum dot,"Spin-dependent transport measurements through a double quantum dot are a
valuable tool for detecting both the coherent evolution of the spin state of a
single electron as well as the hybridization of two-electron spin states. In
this paper, we discuss a model that describes the transport cycle in this
regime, including the effects of an oscillating magnetic field (causing
electron spin resonance) and the effective nuclear fields on the spin states in
the two dots. We numerically calculate the current flow due to the induced spin
flips via electron spin resonance and we study the detector efficiency for a
range of parameters. The experimental data are compared with the model and we
find a reasonable agreement.",0704.1628v1
2007-07-24,Reversal of spin polarization in Fe/GaAs (001) driven by resonant surface states: First-principles calculations,"A minority-spin resonant state at the Fe/GaAs(001) interface is predicted to
reverse the spin polarization with voltage bias of electrons transmitted across
this interface. Using a Green's function approach within the local spin density
approximation we calculate spin-dependent current in a Fe/GaAs/Cu tunnel
junction as a function of applied bias voltage. We find a change in sign of the
spin polarization of tunneling electrons with bias voltage due to the interface
minority-spin resonance. This result explains recent experimental data on spin
injection in Fe/GaAs contacts and on tunneling magnetoresistance in Fe/GaAs/Fe
magnetic tunnel junctions.",0707.3644v1
2011-10-24,Readout of carbon nanotube vibrations based on spin-phonon coupling,"We propose a scheme for spin-based detection of the bending motion in
suspended carbon-nanotubes, using the curvature-induced spin-orbit interaction.
We show that the resulting effective spin-phonon coupling can be used to
down-convert the high-frequency vibration-modulated spin-orbit field to
spin-flip processes at a much lower frequency. This vibration-induced
spin-resonance can be controlled with an axial magnetic field. We propose a
Pauli spin blockade readout scheme and predict that the leakage current shows
pronounced peaks as a function of the external magnetic field. Whereas the
resonant peaks allow for frequency readout, the slightly off-resonant current
is sensitive to the vibration amplitude.",1110.5165v1
2012-12-03,Observation of Resistively Detected Hole Spin Resonance and Zero-field Pseudo-spin Splitting in Epitaxial Graphene,"Electronic carriers in graphene show a high carrier mobility at room
temperature. Thus, this system is widely viewed as a potential future
charge-based high-speed electronic-material to complement- or replace- silicon.
At the same time, the spin properties of graphene have suggested improved
capability for spin-based electronics or spintronics, and spin-based quantum
computing. As a result, the detection, characterization, and transport of spin
have become topics of interest in graphene. Here we report a microwave
photo-excited transport study of monolayer and trilayer graphene that reveals
an unexpectedly strong microwave-induced electrical-response and dual
microwave-induced resonances in the dc-resistance. The results suggest the
resistive detection of spin resonance, and provide a measurement of the
g-factor, the spin relaxation time, and the sub-lattice degeneracy-splitting at
zero-magnetic-field.",1212.0329v1
2014-05-06,Mechanically induced spin resonance in a carbon nanotube,"The electron spin is a promising qubit candidate for quantum computation and
quantum information. Here we propose and analyze a mechanically-induced single
electron spin resonance, which amounts to a rotation of the spin about the
$x$-axis in a suspended carbon nanotube. The effect is based on the coupling
between the spin and the mechanical degree of freedom due to the intrinsic
curvature-induced spin-orbit coupling. A rotation about the $z$-axis is
obtained by the off-resonant external electric driving field. Arbitrary-angle
rotations of the single electron spin about any axis in the $x$-$z$ plane can
be obtained with a single operation by varying the frequency and the strength
of the external electric driving field. With multiple steps combining the
rotations about the $x$- and $z$-axes, arbitrary-angle rotations about
arbitrary axes can be constructed, which implies that any single-qubit gate of
the electron spin qubit can be performed. We simulate the system numerically
using a master equation with realistic parameters.",1405.1347v1
2015-11-04,Enhanced strain coupling of nitrogen vacancy spins to nanoscale diamond cantilevers,"Nitrogen vacancy (NV) centers can couple to confined phonons in diamond
mechanical resonators via the effect of lattice strain on their energy levels.
Access to the strong spin-phonon coupling regime with this system requires
resonators with nanoscale dimensions in order to overcome the weak strain
response of the NV ground state spin sublevels. In this work, we study NVs in
diamond cantilevers with lateral dimensions of a few hundred nm. Coupling of
the NV ground state spin to the mechanical mode is detected in electron spin
resonance (ESR), and its temporal dynamics are measured via spin echo. Our
small mechanical mode volume leads to a 10-100X enhancement in spin-phonon
coupling strength over previous NV-strain coupling demonstrations. This is an
important step towards strong spin-phonon coupling, which can enable
phonon-mediated quantum information processing and quantum metrology.",1511.01548v1
2016-01-20,Electron Paramagnetic Resonance of Single Magnetic Moment on a Surface,"We address electron spin resonance of single magnetic moments in a tunnel
junction using time-dependent electric fields and spin-polarized current. We
show that the tunneling current directly depends on the local magnetic moment
and that the frequency of the external electric field mixes with the
characteristic Larmor frequency of the local spin. The importance of the
spin-polarized current induced anisotropy fields acting on the local spin
moment is, moreover, demonstrated. Our proposed model thus explains the absence
of an electron spin resonance for a half integer spin, in contrast with the
strong signal observed for an integer spin.",1601.05195v2
2016-07-15,Theory of spin-coherent transport through a defect spin state in a metal/ferromagnet tunnel junction during ferromagnetic resonance,"We describe the coherent interaction between a defect spin at the interface
of a ferromagnet and a non-magnetic material, under bias and when the
magnetization of the ferromagnetic contact precesses during ferromagnetic
resonance. The magnet filters charge carriers by preferentially allowing in
parallel spins, which leads to a dynamic spin accumulation on the defect. Local
effective fields acting on the defect spin site modify the defect spin's
precession, which also modifies the charge current through the defect. This new
form of current-detected spin resonance reveals the local environment of the
defect, and thus can yield the defect identity.",1607.04535v2
2016-08-30,Quantum speed limit time in a magnetic resonance,"A visualization for dynamics of a qudit spin vector in a time-dependent
magnetic field is realized by means of mapping a solution for a spin vector on
the three-dimensional spherical curve (vector hodograph). The obtained results
obviously display the quantum interference of precessional and nutational
effects on the spin vector in the magnetic resonance. For any spin the bottom
bounds of the quantum speed limit time (QSL) are found. It is shown that the
bottom bound goes down when using multilevel spin systems. Under certain
conditions the non-nil minimal time, which is necessary to achieve the
orthogonal state from the initial one, is attained at spin S=2. An estimation
of the product of two and three standard deviations of the spin components are
presented. We discuss the dynamics of the mutual uncertainty, conditional
uncertainty and conditional variance in terms of spin standard deviations. The
study can find practical applications in the magnetic resonance, 3D
visualization of computational data and in designing of optimized information
processing devices for quantum computation and communication.",1608.08537v3
2019-05-02,Negligible thermal contributions to the spin pumping signal in ferromagnetic metal-Platinum bilayers,"Spin pumping by ferromagnetic resonance is one of the most common technique
to determine spin hall angles, Edelstein lengths or spin diffusion lengths of a
large variety of materials. In recent years, rising concerns have appeared
regarding the interpretation of these experiments, underlining that the signal
could arise purely from thermoelectric effects, rather than from coherent spin
pumping. Here, we propose a method to evaluate the presence or absence of
thermal effects in spin pumping signals, by combining bolometry and spin
pumping by ferromagnetic resonance measurements, and comparing their timescale.
Using a cavity to perform the experiments on Pt\Permalloy and La0.7Sr0.3MnO3\Pt
samples, we conclude on the absence of any measurable thermoelectric
contribution such as the spin Seebeck and anomalous Nernst effects at resonance",1905.00771v2
2019-05-07,Spin Berry phase in a helical edge state: Sz nonconservation and transport signatures,"Topological protection of edge state in quantum spin Hall systems relies only
on time-reversal symmetry. Hence, S z conservation on the edge can be relaxed
which can have an interferometric manifestation in terms of spin Berry phase.
Primarily it could lead to the generation of spin Berry phase arising from a
closed loop dynamics of electrons. Our work provides a minimal framework to
generate and detect these effects by employing both spin-unpolarized and
spin-polarized leads. We show that spin-polarized leads could lead to
resonances or anti-resonances in the two-terminal conductance of the
interferometer. We further show that the positions of these anti-resonances (as
a function of energy of the incident electron) get shifted owing to the
presence of spin Berry phase. Finally, we present simulations of a device setup
using KWANTpackage which put our theoretical predictions on firm footing.",1905.02801v2
2021-10-26,Generic character of charge and spin density waves in superconducting cuprates,"Understanding the nature of charge density waves (CDW) in cuprate
superconductors has been complicated by material specific differences. A
striking example is the opposite doping dependence of the CDW ordering
wavevector in La-based and Y-based compounds, the two families where charge
ordering is strongest and best characterized. Here we report a combined
resonant soft X-ray scattering (RSXS) and neutron scattering study of charge
and spin density waves in isotopically enriched La$_{1.8-x}$ Eu$_{0.2}$
Sr$_{x}$ CuO$_{4}$ over a range of doping $0.07 \leq x \leq 0.20$. For all
dopings studied by RSXS, we find that the CDW amplitude is approximately
temperature-independent and develops well above experimentally accessible
temperatures. Surprisingly, the CDW ordering wavevector shows a non-monotonic
temperature dependence, with a sudden change occurring at temperatures near the
SDW onset temperature. We describe this behavior with a Landau-Ginzburg theory
for an incommensurate CDW in a metallic system with a finite charge
compressibility and CDW-SDW coupling. Our Landau-Ginzburg analysis suggests
that the ordering wavevector at high temperatures decreases with increased
doping. This behavior is opposite to the trend at low temperatures and highly
reminiscent of the doping dependence seen in YBa$_2$ Cu$_3$ O$_{6+\delta}$ ,
suggesting a common origin of the CDW in hole-doped cuprate superconductors.",2110.13991v1
2009-05-18,Bulk Spin-Hall Effect,"We show that a two-dimensional spin-orbit-coupled system in the presence of a
charge/spin-density wave with a wave-vector perpendicular to an applied
electric field supports bulk manifestations of the direct/inverse spin-Hall
effect. We develop a theory of this phenomenon in the framework of the spin
diffusion equation formalism and show that, due to the inhomogeneity created by
a spin-grating, an anomalous bulk charge-density wave is induced away from
sample boundaries. The optimal conditions for the observation of the effect are
determined. The main experimental manifestation of the bulk spin-Hall effect,
the induced charge/spin-density-wave, is characterized by a pi/2-phase shift
relative to the initial non-homogeneous spin/charge-polarization profile and
has a non-monotonic time-varying amplitude.",0905.2771v1
2011-12-21,Direct detection of magnon spin transport by the inverse spin Hall effect,"Conversion of traveling magnons into an electron carried spin current is
demonstrated in a time resolved experiment using a spatially separated
inductive spin-wave source and an inverse spin Hall effect (ISHE) detector. A
short spin-wave packet is excited in a yttrium-iron garnet (YIG) waveguide by a
microwave signal and is detected at a distance of 3 mm by an attached Pt layer
as a delayed ISHE voltage pulse. The delay in the detection appears due to the
finite spin-wave group velocity and proves the magnon spin transport. The
experiment suggests utilization of spin waves for the information transfer over
macroscopic distances in spintronic devices and circuits.",1112.4969v1
2013-07-29,Generalized spin-wave theory: application to the bilinear-biquadratic model,"We present a generalized spin-wave theory (GSWT) for treating spin
Hamiltonians of arbitrary spin $S$. The generalization consists of an extension
of the traditional spin-wave theory from SU(2) to SU($N$). Low energy
excitations are waves of the local order parameter that fluctuates in the
SU($N$) space of unitary transformations of the local spin states, instead of
the SU(2) space of local spin rotations. Since the generators of the SU($N$)
group can be represented as bilinear forms in $N$-flavored bosons, the
low-energy modes of the GSWT are described with $N-1$ different bosons. The
generalization allows treating quantum spin systems whose ground state exhibit
multipolar ordering as well as detecting instabilities of magnetically ordered
states (dipolar ordering) towards higher multipolar orderings. We illustrate
these advantages by applying the GSWT to a bilinear-biquadratic model of
arbitrary spin $S$ on hypercubic lattices.",1307.7731v1
2015-07-07,"Magnetic order, spin waves and fluctuations in the triangular antiferromagnet La2Ca2MnO7","We report magnetic susceptibility, specific heat and muon spin relaxation
(muSR) experiments on the triangular antiferromagnet La2Ca2MnO7 which develops
a genuine two-dimensional, three-sublattice \sqrt{3} \times \sqrt{3} magnetic
order below T_N = 2.8 K. From the susceptibility and specific heat data an
estimate of the exchange interaction is derived. A value for the spin-wave gap
is obtained from the latter data. The analysis of a previously reported
inelastic neutron scattering study yields values for the exchange and spin-wave
gap compatible with the results obtained from macroscopic measurements. An
appreciable entropy is still missing at 10 K that may be ascribed to intense
short-range correlations. The critical paramagnetic fluctuations extend far
above T_N, and can be partly understood in terms of two-dimensional spin-wave
excitations. While no spontaneous muSR field is observed below T_N, persistent
spin dynamics is found. Short-range correlations are detected in this
temperature range. Their relation to a possible molecular spin substructure and
the observed exotic spin fluctuations is discussed.",1507.01740v1
2020-01-21,Nonresonant amplification of coherent spin waves through voltage-induced interface magnetoelectric effect and spin-transfer torque,"We present new mechanism for manipulation of the spin-wave amplitude through
the use of the dynamic charge-mediated magnetoelectric effect in ultrathin
multilayers composed of dielectric thin-film capacitors separated by a
ferromagnetic bilayer. Propagating spin waves can be amplified and attenuated
with rising and decreasing slopes of the oscillating voltage, respectively,
locally applied to the sample. The way the spin accumulation is generated makes
the interaction of the spin-transfer torque with the magnetization dynamics
mode-selective and restricted to some range of spin-wave frequencies, which is
in contrary to known types of the spin-transfer torque effects. The interfacial
nature of spin-dependent screening allows to reduce the thickness of the fixed
magnetization layer to a few nanometers, thus the proposed effect significantly
contributes toward realization of the magnonic devices and also miniaturization
of the spintronic devices.",2001.07474v1
2010-03-13,Motion and gravitational wave forms of eccentric compact binaries with orbital-angular-momentum-aligned spins under next-to-leading order in spin-orbit and leading order in spin(1)-spin(2) and spin-squared couplings,"A quasi-Keplerian parameterisation for the solutions of second post-Newtonian
(PN) accurate equations of motion for spinning compact binaries is obtained
including leading order spin-spin and next-to-leading order spin-orbit
interactions. Rotational deformation of the compact objects is incorporated.
For arbitrary mass ratios the spin orientations are taken to be parallel or
anti-parallel to the orbital angular momentum vector. The emitted gravitational
wave forms are given in analytic form up to 2PN point particle, 1.5PN spin
orbit and 1PN spin-spin contributions, where the spins are counted of 0PN
order.",1003.2735v4
2016-02-12,Thermal generation of spin current in a helimagnetic multiferroic hexaferrite,"We report the experimental observation of longitudinal spin Seebeck effect in
a multiferroic helimagnet Ba0.5Sr1.5Zn2Fe12O22. Temperature gradient applied
normal to Ba0.5Sr1.5Zn2Fe12O22/Pt interface generates inverse spin Hall voltage
of spin current origin in Pt, whose magnitude was found to be proportional to
bulk magnetization of Ba0.5Sr1.5Zn2Fe12O22 even through the successive magnetic
transitions among various helimagnetic and ferrimagnetic phases. This finding
demonstrates that the helimagnetic spin wave can be an effective carrier of
spin current. By controlling the population ratio of spin-helicity domains
characterized by clockwise/counter-clockwise manner of spin rotation with use
of poling electric field in the ferroelectric helimagnetic phase, we found that
spin-helicity domain distribution does not affect the magnitude of spin current
injected into Pt. The results suggest that the spin-wave spin current is rather
robust against the spin-helicity domain wall, unlike the case with the
conventional ferromagnetic domain wall.",1602.04011v1
2019-08-27,Inelastic light scattering in the spin cluster Mott insulator Cu$_{2}$OSeO$_{3}$,"Clusters of single spins form the relevant spin entities in the formation of
long-range magnetic order in spin cluster Mott insulators. Such type of spin
order bears resemblance to molecular crystals, and we therefore may expect a
prototypical spin wave spectrum which can be divided into low-energy external
and high-energy internal cluster spin wave modes. Here, we study high-energy
spin cluster excitations in the spin cluster Mott insulator Cu$_{2}$OSeO$_{3}$
by means of spontaneous Raman scattering. Multiple high-energy optical magnon
modes are observed, of which the Raman-activity is shown to originate in the
Elliot-Loudon scattering mechanism. Upon crossing the long-range ordering
transition temperature the magnetic modes significantly broaden, corresponding
to scattering from localized spin excitations within the spin clusters.
Different optical phonon modes show a strong temperature dependence, evidencing
a strong magnetoelectric coupling between optical phonons and the high-energy
spin cluster excitations. Our results support the picture that
Cu$_{2}$OSeO$_{3}$ can be regarded as a solid-state molecular crystal of spin
nature.",1908.10279v1
1997-09-24,Resonance tunneling of polaritons in 1-D chain with a single defect,"We consider propagation of coupled waves (polaritons) formed by a scalar
electromagnetic wave and excitations of a finite one dimensional chain of
dipoles. It is shown that a microscopic defect (an impurity dipole) embedded in
the chain causes resonance tunneling of the electromagnetic wave with the
frequency within the forbidden band between two polariton branches. We
demonstrate that resonance tunneling occurs due to local polariton states
caused by the defect.",9709267v2
2005-08-04,Pseudopotential in resonant regimes,"The zero-range potential approach is extended for the description of
situations where two-body scattering is resonant in arbitrary partial waves.
The formalism generalizes the Fermi pseudopotential which can be used only for
s-wave broad resonances. In a given channel, the interaction is described
either in terms of a contact condition on the wave function or with a family of
pseudopotentials. We show that it is necessary to introduce a regularized
scalar product for wave functions obtained in the zero-range potential
formalism (except for the Fermi pseudopotential). This metrics shows that the
geometry of these Hilbert spaces depends crucially on the interaction.",0508120v3
2002-09-10,"Acceleration and Cyclotron Radiation, Induced by Gravitational Waves","The equations which determine the response of a charged particle moving in a
magnetic field to an incident gravitational wave(GW) are derived in the
linearized approximation to general relativity. We briefly discuss several
astrophysical applications of the derived formulae taking into account the
resonance between the wave and the particle's motion which occurs at
$\omega_g=2\Omega$, whenever the GW is parallel to the constant magnetic field.
In the case where the GW is perpendicular to the constant magnetic field,
magnetic resonances appear at $\omega_g=\Omega$ and $\omega_g=2\Omega$. Such
resonant mechanism may be useful to build models of GW driven cyclotron
emitters.",0209033v1
2005-06-08,Resonant growth of stellar oscillations by incident gravitational waves,"Stellar oscillation under the combined influences of incident gravitational
wave and radiation loss is studied in a simple toy model. The star is
approximated as a uniform density ellipsoid in the Newtonian gravity including
radiation damping through quadrupole formula. The time evolution of the
oscillation is significantly controlled by the incident wave amplitude $h$,
frequency $\nu$ and damping time $\tau$. If a combination $ h \nu \tau $
exceeds a threshold value, which depends on the resonance mode, the resonant
growth is realized.",0506047v1
2007-01-15,Detectability of Mode Resonances in Coalescing Neutron Star Binaries,"Inspirals of neutron star-neutron star binaries are a promising source of
gravitational waves for gravitational wave detectors like LIGO. During the
inspiral, the tidal gravitational field of one of the stars can resonantly
excite internal modes of the other star, resulting in a phase shift in the
gravitational wave signal. We compute using a Fisher-matrix analysis how large
the phase shift must be in order to be detectable. For a $1.4 M_\odot, 1.4
M_\odot$ binary the result is $\sim 8.1, 2.9$ and 1.8 radians, for resonant
frequencies of $16, 32$ and 64 Hz. The measurement accuracies of the other
binary parameters are degraded by inclusion of the mode resonance effect.",0701076v1
2006-10-11,Tunable plasma wave resonant detection of optical beating in high electron mobility transistor,"We report on tunable terahertz resonant detection of two 1.55 &micro;m
cw-lasers beating by plasma waves in AlGaAs/InGaAs/InP high-electron-mobility
transistor. We show that the fundamental plasma resonant frequency and its odd
harmonics can be tuned with the applied gate-voltage in the range 75-490 GHz.
The observed frequency dependence on gate-bias is found to be in good agreement
with the theoretical plasma waves dispersion law.",0610078v1
2005-08-27,Resonant States of Wave Propagation in Disordered System of Bosonic Particles,"We demonstrate the effects of an induced disorder (or a free-orientation :
$\theta$ which is related to the relative direction of scattering of particles
w.r.t. to the normal of the propagating plane-wave front) upon the possible
resonance of the plane (sound) wave propagating in Bose gases by using the
quantum kinetic equations. We firstly present the diverse dispersion relations
obtained by the relevant Pauli-blocking parameter $B$ (which describes the Bose
particles when $B$ is positive) and the free-orientation $\theta$ and then,
based on the acoustic analog, address the possible resonant states.",0508204v1
2009-06-18,Fast electromagnetic response of a thin film of resonant atoms with permanent dipole,"We consider the propagation of extremely short pulses through a dielectric
thin film containing resonant atoms (two level atoms) with permanent dipole.
Assuming that the film width is less than the field wave length, we can solve
the wave equation and reduce the problem to a system of generalized Bloch
equations describing the resonant atoms. We compute the stationary solutions
for a constant irradiation of the film. Superimposing a small amplitude linear
wave we compute the reflection and transmission coefficients. From these, one
can then deduce the different parameters of the model. We believe this
technique could be used in experiments to obtain the medium atomic and
relaxation parameters.",0906.3473v1
2009-08-15,The two-atom energy spectrum in a harmonic trap near a Feshbach resonance at higher partial waves,"Two atoms in an optical lattice may be made to interact strongly at higher
partial waves near a Feshbach resonance. These atoms, under appropriate
constraints, could be bosonic or fermionic. The universal $l=2$ energy spectrum
for such a system, with a caveat, is presented in this paper, and checked with
the spectrum obtained by direct numerical integration of the Schr\""odinger
equation. The results reported here extend those of Yip for p-wave resonance
(Phys. Rev. A {\bf 78}, 013612 (2008)), while exploring the limitations of a
universal expression for the spectrum for the higher partial waves.",0908.2204v1
2010-09-06,"The Past, Present and Future of the Resonant-Mass Gravitational Wave Detectors","Resonant-mass gravitational waves detectors are reviewed from the concept of
gravitational waves and its mathematical derivation, using Einstein's general
relativity, to the present status of bars and spherical detectors, and their
prospects for the future, which include dual detectors and spheres with
non-resonant transducers. The review covers not only the technical aspects of
detectors and the science that will be done, but also analyses the subject in a
historic perspective, covering the various detection efforts over four decades,
starting from Weber's pioneering work.",1009.1138v1
2010-11-16,Resonant Absorption as Mode Conversion? II. Temporal Ray Bundle,"A fast-wave pulse in a simple, cold, inhomogeneous MHD model plasma is
constructed by Fourier superposition over frequency of harmonic waves that are
singular at their respective Alfven resonances. The pulse partially reflects
before reaching the resonance layer, but also partially tunnels through to it
to mode convert to an Alfven wave. The exact absorption/conversion coefficient
for the pulse is shown to be given precisely by a function of transverse
wavenumber tabulated in Paper I of this sequence, and to be independent of
frequency and pulse width.",1011.3808v1
2013-05-23,Robust energy transfer mechanism and critically balanced turbulence via non-resonant triads in nonlinear wave systems,"A robust energy transfer mechanism is found in nonlinear wave systems, which
favours transfers towards modes interacting via non-resonant triads, applicable
in meteorology, nonlinear optics and plasma wave turbulence. Transfer
efficiency is maximal when the frequency mismatch of the non-resonant triad
balances the system's nonlinear frequency: at intermediate levels of
oscillation amplitudes an instability is triggered that explores unstable
manifolds of periodic orbits, so turbulent cascades are most efficient at
intermediate nonlinearity. Numerical simulations confirm analytical
predictions.",1305.5517v2
2016-09-13,A two-way model for nonlinear acoustic waves in a non-uniform lattice of Helmholtz resonators,"Propagation of high amplitude acoustic pulses is studied in a 1D waveguide
connected to a lattice of Helmholtz resonators. An homogenized model has been
proposed by Sugimoto (J. Fluid. Mech., \textbf{244} (1992)), taking into
account both the nonlinear wave propagation and various mechanisms of
dissipation. This model is extended here to take into account two important
features: resonators of different strengths and back-scattering effects. An
energy balance is obtained, and a numerical method is developed. A closer
agreement is reached between numerical and experimental results. Numerical
experiments are also proposed to highlight the effect of defects and of
disorder.",1609.03841v2
2017-07-27,Schumann resonance transients and the search for gravitational waves,"Schumann resonance transients which propagate around the globe can
potentially generate a correlated background in widely separated gravitational
wave detectors. We show that due to the distribution of lightning hotspots
around the globe these transients have characteristic time lags, and this
feature can be useful to further suppress such a background, especially in
searches of the stochastic gravitational-wave background. A brief review of the
corresponding literature on Schumann resonances and lightnings is also given.",1707.09047v2
2019-11-13,On the time-evolution of resonant triads in rotational capillary-gravity water waves,"We investigate an effect of the resonant interaction in the case of
one-directional propagation of capillary-gravity surface waves arising as the
free surface of a rotational water flow. Specifically, we assume a constant
vorticity in the body of the fluid which physically corresponds to an
underlying current with a linear horizontal velocity profile. We consider the
interaction of three distinct modes and we obtain the dynamic equations for a
resonant triad. Setting the constant vorticity equal to zero we recover the
well known integrable three-wave system.",1911.05213v1
2018-10-23,Perfect absorption of water waves by linear or nonlinear critical coupling,"We report on experiments of perfect absorption for surface gravity waves
impinging a wall structured by a subwavelength resonator. By tuning the
geometry of the resonator, a balance is achieved between the radiation damping
and the intrinsic viscous damping, resulting in perfect absorption by critical
coupling. Besides, it is shown that the resistance of the resonator, hence the
intrinsic damping, can be controlled by the wave amplitude, which provides a
way for perfect absorption tuned by nonlinear mechanisms. The perfect absorber
that we propose, without moving parts or added material, is simple, robust and
it presents a deeply subwavelength ratio wavelength/size $\simeq 18$.",1810.09884v1
2014-05-30,Eliminating Structural Loss in Optomechanical Resonators Using Elastic Wave Interference,"Optomechanical resonators suffer from the dissipation of mechanical energy
through the necessary anchors enabling the suspension of the structure. Here we
show that such structural loss in an optomechnaical oscillator can be almost
completely eliminated through the destructive interference of elastic waves
using dual-disk resonators. We also present both analytical and numerical model
that predicts the observed interference of elastic waves. Our experimental data
reveal unstressed SiN devices with mechanical Q-factors up to $10^4$ at
mechanical frequencies of $f=102$ MHz ($fQ = 10^{12}$) at room temperature.",1406.0029v1
2018-11-19,Application of the method of multiple scales to unravel energy exchange in nonlinear locally resonant metamaterials,"In this paper, the effect of weak nonlinearities in 1D locally resonant
metamaterials is investigated via the method of multiple scales. Commonly
employed to the investigate the effect of weakly nonlinear interactions on the
free wave propagation through a phononic structure or on the dynamic response
of a Duffing oscillator, the method of multiple scales is here used to
investigate the forced wave propagation through locally resonant metamaterials.
The perturbation approach reveals that energy exchange may occur between
propagative and evanescent waves induced by quadratic nonlinear local
interaction.",1812.05713v1
2020-02-13,Solitary Waves in Mass-in-Mass Lattices,"We consider the existence of spatially localized traveling wave solutions of
the mass-in-mass lattice. Under an anti-resonance condition first discovered by
Kevrekidis, Stefanov and Xu, we prove that such solutions exist in two
distinguished limits, the first where the mass of the internal resonator is
small and the second where the internal spring is very stiff. We then
numerically simulate the solutions and these simulations indicate that the
anti-resonant traveling waves are weakly unstable",2002.05573v1
2024-01-02,Scattering from time-modulated subwavelength resonators,"We consider wave scattering from a system of highly contrasting resonators
with time-modulated material parameters. In this setting, the wave equation
reduces to a system of coupled Helmholtz equations that models the scattering
problem. We consider the one-dimensional setting. In order to understand the
energy of the system, we prove a novel higher-order discrete, capacitance
matrix approximation of the subwavelength resonant quasifrequencies. Further,
we perform numerical experiments to support and illustrate our analytical
results and show how periodically time-dependent material parameters affect the
scattered wave field.",2401.01914v1
2024-02-15,Switching waves-induced broadband Kerr frequency comb in fiber Fabry-Perot resonators,"We report the generation of broadband frequency combs in fiber Fabry-Perot
resonators in the normal dispersion regime enabled by the excitation of
switching waves. We theoretically characterise the process by means of a
transverse linear stability analysis of the Lugiato-Lefever equation, enabling
precise prediction of the switching waves' frequencies. Experimentally, we
employed a pulsed-pump fiber Fabry-Perot resonator operating in the normal
dispersion regime, integrated into an all-fiber experimental setup. The
synchronisation mismatch and the influence of dispersion is thoroughly
discussed, unveiling the potential to generate a frequency comb spanning over
15 THz bandwidth, specifically leveraging a flattened low dispersion cavity.",2402.09777v1
1998-06-16,Ray and wave chaos in asymmetric resonant optical cavities,"Optical resonators are essential components of lasers and other
wavelength-sensitive optical devices. A resonator is characterized by a set of
modes, each with a resonant frequency omega and resonance width Delta
omega=1/tau, where tau is the lifetime of a photon in the mode. In a
cylindrical or spherical dielectric resonator, extremely long-lived resonances
are due to `whispering gallery' modes in which light circulates around the
perimeter trapped by total internal reflection. These resonators emit light
isotropically. Recently, a new category of asymmetric resonant cavities (ARCs)
has been proposed in which substantial shape deformation leads to partially
chaotic ray dynamics. This has been predicted to give rise to a universal,
frequency-independent broadening of the whispering-gallery resonances, and
highly anisotropic emission. Here we present solutions of the wave equation for
ARCs which confirm many aspects of the earlier ray-optics model, but also
reveal interesting frequency-dependent effects characteristic of quantum chaos.
For small deformations the lifetime is controlled by evanescent leakage, the
optical analogue of quantum tunneling. We find that the lifetime is much
shortened by a process known as `chaos-assisted tunneling'. In contrast, for
large deformations (~10%) some resonances are found to have longer lifetimes
than predicted by the ray chaos model due to `dynamical localization'.",9806017v1
2014-02-17,An Analytic Model for Buoyancy Resonances in Protoplanetary Disks,"Zhu, Stone, and Rafikov (2012) found in 3D shearing box simulations a new
form of planet-disk interaction that they attributed to a vertical buoyancy
resonance in the disk. We describe an analytic linear model for this
interaction. We adopt a simplified model involving azimuthal forcing that
produces the resonance and permits an analytic description of its structure. We
derive an analytic expression for the buoyancy torque and show that the
vertical torque distribution agrees well with results of Athena simulations and
a Fourier method for linear numerical calculations carried out with the same
forcing. The buoyancy resonance differs from the classic Lindblad and
corotation resonances in that the resonance lies along tilted planes. Its width
depends on damping effects and is independent of the gas sound speed. The
resonance does not excite propagating waves. At a given large azimuthal
wavenumber k_y > 1/h (for disk thickness h), the buoyancy resonance exerts a
torque over a region that lies radially closer to the corotation radius than
the Lindblad resonance. Because the torque is localized to the region of
excitation, it is potentially subject to the effects of nonlinear saturation.
In addition, the torque can be reduced by the effects of radiative heat
transfer between the resonant region and its surroundings. For each azimuthal
wavenumber, the resonance establishes a large scale density wave pattern in a
plane within the disk.",1402.4162v1
2015-02-23,Theoretical characterization of the collective resonance states underlying the xenon giant dipole resonance,"We present a detailed theoretical characterization of the two fundamental
collective resonances underlying the xenon giant dipole resonance (GDR). This
is achieved consistently by two complementary methods implemented within the
framework of the configuration-interaction singles (CIS) theory. The first
method accesses the resonance states by diagonalizing the many-electron
Hamiltonian using the smooth exterior complex scaling technique. The second
method involves a new application of the Gabor analysis to wave-packet
dynamics. We identify one resonance at an excitation energy of 74 eV with a
lifetime of 27 as, and the second at 107 eV with a lifetime of 11 as. Our work
provides a deeper understanding of the nature of the resonances associated with
the GDR: a group of close-lying intrachannel resonances splits into two
far-separated resonances through interchannel couplings involving the 4d
electrons. The CIS approach allows a transparent interpretation of the two
resonances as new collective modes. Due to the strong entanglement between the
excited electron and the ionic core, the resonance wave functions are not
dominated by any single particle-hole state. This gives rise to plasma-like
collective oscillations of the 4d shell as a whole.",1502.06462v1
2022-04-06,Asymptotics of the meta-atom: plane wave scattering by a single Helmholtz resonator,"Using a combination of multipole methods and the method of matched
asymptotics, we present a solution procedure for acoustic plane wave scattering
by a single Helmholtz resonator in two dimensions. Closed-form representations
for the multipole scattering coefficients of the resonator are derived, valid
at low frequencies, with three fundamental configurations examined in detail:
the thin-walled, moderately thick-walled, and very thick-walled limits.
Additionally, we examine the impact of dissipation for very thick-walled
resonators, and also numerically evaluate the scattering, absorption, and
extinction cross sections (efficiencies) for representative resonators in all
three wall thickness regimes. In general, we observe strong enhancement in both
the scattered fields and cross sections at the Helmholtz resonance frequencies.
As expected, dissipation is shown to shift the resonance frequency, reduce the
amplitude of the field, and reduce the extinction efficiency at the fundamental
Helmholtz resonance. Finally, we confirm results in the literature on
Willis-like coupling effects for this resonator design, and crucially, connect
these findings to earlier works by the authors on two-dimensional arrays of
resonators, deducing that depolarisability effects (off-diagonal terms) for a
single resonator do not ensure the existence of Willis coupling effects
(bianisotropy) in bulk.",2204.02840v1
2021-01-25,Long-range spin-wave propagation in transversely magnetized nano-scaled conduits,"Magnonics attracts increasing attention in the view of novel low-energy
computation technologies based on spin waves. Recently, spin-wave propagation
in longitudinally magnetized nano-scaled spin-wave conduits was demonstrated,
proving the fundamental feasibility of magnonics at the sub-100 nm scale.
Transversely magnetized nano-conduits, which are of great interest in this
regard as they offer a large group velocity and a potentially chirality-based
protected transport of energy, have not yet been investigated due to their
complex internal magnetic field distribution. Here, we present a study of
propagating spin waves in a transversely magnetized nanoscopic yttrium iron
garnet conduit of 50 nm width. Space and time-resolved micro-focused
Brillouin-light-scattering spectroscopy is employed to measure the spin-wave
group velocity and decay length. A long-range spin-wave propagation is observed
with a decay length of up to (8.0+-1.5) {\mu}m and a large spin-wave lifetime
of up to (44.7+-9.1) ns. The results are supported with micromagnetic
simulations, revealing a single-mode dispersion relation in contrast to the
common formation of localized edge modes for microscopic systems. Furthermore,
a frequency non-reciprocity for counter-propagating spin waves is observed in
the simulations and the experiment, caused by the trapezoidal cross-section of
the structure. The revealed long-distance spin-wave propagation on the
nanoscale is particularly interesting for an application in spin-wave devices,
allowing for long-distance transport of information in magnonic circuits, as
well as novel low-energy device architectures.",2101.10192v1
2008-09-02,Neutrino mass spectrum from gravitational waves generated by double neutrino spin-flip in supernovae,"The supernova (SN) neutronization phase produces mainly electron ($\nu_e$)
neutrinos, the oscillations of which must take place within a few
mean-free-paths of their resonance surface located nearby their neutrinosphere.
The state-of-the-art on the SN dynamics suggests that a significant part of
these $\nu_e$ can convert into right-handed neutrinos in virtue of the
interaction of the electrons and the protons flowing with the SN outgoing
plasma, whenever the Dirac neutrino magnetic moment be of strength $\mu_\nu <
10^{-11} \mu_{\rm B}$, with $\mu_{\rm B}$ being the Bohr magneton. In the
supernova envelope, part of these neutrinos can flip back to the left-handed
flavors due to the interaction of the neutrino magnetic moment with the
magnetic field in the SN expanding plasma (Kuznetsov & Mikheev 2007; Kuznetsov,
Mikheev & Okrugin 2008), a region where the field strength is currently
accepted to be $B \gtrsim 10^{13}$ ~G. This type of $\nu$ oscillations were
shown to generate powerful gravitational wave (GW) bursts (Mosquera Cuesta
2000, Mosquera Cuesta 2002, Mosquera Cuesta & Fiuza 2004, Loveridge 2004). If
such double spin-flip mechanism does run into action inside the SN core, then
the release of both the oscillation-produced $\nu_\mu$s, $\nu_\tau$s and the GW
pulse generated by the coherent $\nu$ spin-flips provides a unique emission
offset $\Delta T^{emission}_{\rm GW} \leftrightarrow \nu = 0$ for measuring the
$\nu$ travel time to Earth. As massive $\nu$s get noticeably delayed on its
journey to Earth with respect to the Einstein GW they generated during the
reconversion transient, then the accurate measurement of this time-of-flight
delay by SNEWS + LIGO, VIRGO, BBO, DECIGO, etc., might readily assess the
absolute $\nu$ mass spectrum.",0809.0526v1
2021-02-03,Charge ordering in Ir dimers in the ground state of Ba$_5$AlIr$_2$O$_{11}$,"It has been well established experimentally that the interplay of electronic
correlations and spin-orbit interactions in Ir$^{4+}$ and Ir$^{5+}$ oxides
results in insulating J$_{\rm eff}$=1/2 and J$_{\rm eff}$=0 ground states,
respectively. However, in compounds where the structural dimerization of iridum
ions is favourable, the direct Ir $d$--$d$ hybridisation can be significant and
takes a key role. Here, we investigate the effects of direct Ir $d$--$d$
hybridisation in comparison with electronic correlations and spin-orbit
coupling in Ba$_5$AlIr$_2$O$_{11}$, a compound with Ir dimers. Using a
combination of $ab$ $initio$ many-body wave function quantum chemistry
calculations and resonant inelastic X-ray scattering (RIXS) experiments, we
elucidate the electronic structure of Ba$_5$AlIr$_2$O$_{11}$. We find excellent
agreement between the calculated and the measured spin-orbit excitations.
Contrary to the expectations, the analysis of the many-body wave function shows
that the two Ir (Ir$^{4+}$ and Ir$^{5+}$) ions in the Ir$_2$O$_9$ dimer unit in
this compound preserve their local J$_{\rm eff}$ character close to 1/2 and 0,
respectively. The local point group symmetry at each of the Ir sites assumes an
important role, significantly limiting the direct $d$--$d$ hybridisation. Our
results emphasize that minute details in the local crystal field (CF)
environment can lead to dramatic differences in electronic states in iridates
and 5$d$ oxides in general.",2102.02178v1
2022-03-16,Discovery of an electronic crystal in a cuprate Mott insulator,"Copper oxide high temperature superconductors universally exhibit multiple
forms of electronically ordered phases that break the native translational
symmetry of the CuO2 planes. The interplay between these orders and the
superconducting ground state, as well as how they arise through doping a Mott
insulator, is essential to decode the mechanisms of high-temperature
superconductivity. Over the years, various forms of electronic liquid crystal
phases including charge/spin stripes and incommensurate charge-density-waves
(CDWs) were found to emerge out of a correlated metallic ground state in
underdoped cuprates. Early theoretical studies also predicted the emergence of
a Coulomb-frustrated 'charge crystal' phase in the very lightly-doped,
insulating limit of the CuO2 planes. Here, we use resonant X-ray scattering,
electron transport, and muon spin rotation measurements to fully resolve the
electronic and magnetic ground state and search for signatures of charge order
in very lightly hole-doped cuprates from the RBa2Cu3O7-d family (RBCO; R: Y or
rare earth). X-ray scattering data from RBCO films reveal a breaking of
translational symmetry more pervasive than was previously known, extending down
to the Mott limit. The ordering vector of this charge crystal state is linearly
connected to the charge-density-waves of underdoped RBCO, suggesting that the
former phase is a precursor to the latter as hole doping is increased. Most
importantly, the coexistence of charge and spin order in RBCO suggests that
this electronic symmetry-breaking state is common to the CuO2 planes in the
very lightly-doped regime. These findings bridge the gap between the Mott
insulating state and the underdoped metallic state and underscore the prominent
role of Coulomb-frustrated electronic phase separation among all cuprates.",2203.08872v1
1999-08-16,Laser Excitation of Polarization Waves in a Frozen Gas,"Laser experiments with optically excited frozen gases entail the excitation
of polarization waves. In a continuum approximation the waves are
dispersionless, but their frequency depends on the direction of the propagation
vector. An outline is given of the theory of transient phenomena that involve
the excitation of these waves by a resonant dipole-dipole transfer process.",9908230v2
2005-12-28,Spin-1 gravitational waves. Theoretical and experimental aspects,"Exact solutions of Einstein field equations invariant for a non-Abelian
2-dimensional Lie algebra of Killing fields are described. Physical properties
of these gravitational fields are studied, their wave character is checked by
making use of covariant criteria and the observable effects of such waves are
outlined. The possibility of detection of these waves with modern detectors,
spherical resonant antennas in particular, is sketched.",0512159v1
2004-07-19,Four-wave mixing of linear waves and solitons in fibres with higher order dispersion,"We derive phase-matching conditions for four-wave mixing between solitons and
linear waves in optical fibres with arbitrary dispersion and demonstrate
resonant excitation of new spectral components via this process.",0407097v1
2007-11-03,Sinusoidal excitations in reduced Maxwell-Duffing model,"Sinusoidal wave solutions are obtained for reduced Maxwell-Duffing equations
describing the wave propagation in a non-resonant atomic medium. These
continuous wave excitations exist when the medium is initially polarized by an
electric field. Other obtained solutions include both mono-frequency and
cnoidal waves.",0711.0449v1
2010-01-10,Discrete wave turbulence of rotational capillary water waves,"We study the discrete wave turbulent regime of capillary water waves with
constant non-zero vorticity. The explicit Hamiltonian formulation and the
corresponding coupling coefficient are obtained. We also present the
construction and investigation of resonance clustering. Some physical
implications of the obtained results are discussed.",1001.1497v2
2016-05-23,The role of Alfvén wave heating in solar prominences,"Observations have shown that magnetohydrodynamic waves over a large frequency
range are ubiquitous in solar prominences. The waves are probably driven by
photospheric motions and may transport energy up to prominences suspended in
the corona. Dissipation of wave energy can lead to heating of the cool
prominence plasma, so contributing to the local energy balance within the
prominence. Here we discuss the role of Alfv\'en wave dissipation as a heating
mechanism for the prominence plasma. We consider a slab-like quiescent
prominence model with a transverse magnetic field embedded in the solar corona.
The prominence medium is modelled as a partially ionized plasma composed of a
charged ion-electron single fluid and two separate neutral fluids corresponding
to neutral hydrogen and neutral helium. Friction between the three fluids acts
as a dissipative mechanism for the waves. The heating caused by
externally-driven Alfv\'en waves incident on the prominence slab is
analytically explored. We find that the dense prominence slab acts as a
resonant cavity for the waves. The fraction of incident wave energy that is
channelled into the slab strongly depends upon the wave period, $P$. Using
typical prominence conditions, we obtain that wave energy trapping and
associated heating are negligible when $P \gtrsim 100$ s, so that it is
unlikely that those waves have a relevant influence on prominence energetics.
When $1$ s $\lesssim P \lesssim 100$ s the energy absorption into the slab
shows several sharp and narrow peaks, that can reach up to 100%, when the
incident wave frequency matches a cavity resonance of the slab. Wave heating is
enhanced at those resonant frequencies. Conversely, when $P \lesssim 1$ s
cavity resonances are absent, but the waves are heavily damped by the strong
dissipation. We estimate that wave heating may compensate for about 10% of
radiative losses of the prominence plasma.",1605.07048v1
2023-02-26,Reducibility of linear quasi-periodic Hamiltonian derivative wave equations and half-wave equations under the Brjuno conditions,"In this paper, we prove the reducibility for some linear quasi-periodic
Hamiltonian derivative wave and half-wave equations under the
Brjuno-R\""{u}ssmann non-resonance conditions. This generalizes KAM theory by
P\""{o}schel in [38] from the finite dimensional Hamiltonian systems to
Hamiltonian PDEs.",2302.13287v1
1998-01-15,Solitary Waves of Planar Ferromagnets and the Breakdown of the Spin-Polarized Quantum Hall Effect,"A branch of uniformly-propagating solitary waves of planar ferromagnets is
identified. The energy dispersion and structures of the solitary waves are
determined for an isotropic ferromagnet as functions of a conserved momentum.
With increasing momentum, their structure undergoes a transition from a form
ressembling a droplet of spin-waves to a Skyrmion/anti-Skyrmion pair. An
instability to the formation of these solitary waves is shown to provide a
mechanism for the electric field-induced breakdown of the spin-polarized
quantum Hall effect.",9801160v1
2015-03-16,Stochastic Quantum Trajectories without a Wave Function,"After summarizing three versions of trajectory-based quantum mechanics, it is
argued that only the original formulation due to Bohm, which uses the
Schr\""odinger wave function to guide the particles, can be readily extended to
particles with spin. To extend the two wave function-free formulations, it is
argued that necessarily particle trajectories not only determine location, but
also spin. Since spin values are discrete, it is natural to revert to a
variation of Bohm's pilot wave formulation due originally to Bell. It is shown
that within this formulation with stochastic quantum trajectories, a wave
function free formulation can be obtained.",1503.04868v1
2012-09-19,Asymmetry of modal profiles of dipole-exchange spin waves in thin high-magnetic moment metallic ferromagnetic films,"The asymmetry of the modal profiles for dipole-exchange spin waves
propagating in in-plane magnetized ferromagnetic films at a right angle to the
applied magnetic field has been investigated theoretically. It was found that
in the large-magnetic moment ferromagnetic metallic films with typical
thicknesses 10-60 nm the fundamental mode of the spectrum is localized at the
surface opposite to the surface of localization of the exchange-free
Damon-Eshbach surface wave. This anomalous localization of the wave does not
affect the non-reciprocity of spin wave excitation by microstrip and coplanar
transducers but may be detected in other types of experiments.",1209.4153v1
2019-06-16,Spin and valley waves in Dirac semimetals with population imbalance,"We find an intervalley wave collective mode in two- and three-dimensional
Dirac semimetals in the presence of a valley population imbalance. The
dispersion relation of this mode is gapless, proportional to the square of the
wave vector at small frequencies, and inversely proportional to the
electron-electron exchange interaction energy. The valley wave serves as an
energy gain source for the external field, that generates the intervalley
transitions. The spin wave analog is discussed for the case of a semimetal with
nonequilibrium spin orientation.",1906.06674v2
2014-10-23,Nanometre-scale probing of spin waves using single electron spins,"Correlated-electron systems support a wealth of magnetic excitations, ranging
from conventional spin waves to exotic fractional excitations in
low-dimensional or geometrically-frustrated spin systems. Probing such
excitations on nanometre length scales is essential for unravelling the
underlying physics and developing new spintronic nanodevices. However, no
established technique provides real-space, few-nanometre-scale probing of
correlated-electron magnetic excitations under ambient conditions. Here we
present a solution to this problem using magnetometry based on single
nitrogen-vacancy (NV) centres in diamond. We focus on spin-wave excitations in
a ferromagnetic microdisc, and demonstrate local, quantitative, and
phase-sensitive detection of the spin-wave magnetic field at ~50 nm from the
disc. We map the magnetic-field dependence of spin-wave excitations by
detecting the associated local reduction in the disc's longitudinal
magnetization. In addition, we characterize the spin-noise spectrum by NV-spin
relaxometry, finding excellent agreement with a general analytical description
of the stray fields produced by spin-spin correlations in a 2D magnetic system.
These complementary measurement modalities pave the way towards imaging the
local excitations of systems such as ferromagnets and antiferromagnets,
skyrmions, atomically assembled quantum magnets, and spin ice.",1410.6423v2
2002-08-29,Enrichment of CH3F nuclear spin isomers by resonant microwave radiation,"Theoretical model of the coherent control of nuclear spin isomers by
microwave radiation has been developed. Model accounts the M-degeneracy of
molecular states and molecular center-of-mass motion. The model has been
applied to the 13CH3F molecules. Microwave radiation excites the para state
(J=11,K=1) which is mixed by the nuclear spin-spin interaction with the ortho
state (9,3). Dependencies of the isomer enrichment and conversion rates on the
radiation frequency have been calculated. Both spectra consist of two
resonances situated at the centers of allowed and forbidden (by nuclear spin)
transitions in the molecule. Larger enrichment, up to 7%, can be produced by
strong radiation resonant to the forbidden transition. The spin conversion rate
can be increased by 2 orders of magnitude at this resonance.",0208099v1
2009-03-14,Incommensurate spin resonance in URu2Si2,"We focus on inelastic neutron scattering in $URu_2Si_2$ and argue that
observed gap in the fermion spectrum naturally leads to the spin feature
observed at energies $\omega_{res} = 4-6 meV$ at momenta at $\bQ^* = (1\pm 0.4,
0,0)$. We discuss how spin features seen in $URu_2Si_2$ can indeed be thought
of in terms of {\em spin resonance} that develops in HO state and is {\em not
related} to superconducting transition at 1.5K. In our analysis we assume that
the HO gap is due to a particle-hole condensate that connects nested parts of
the Fermi surface with nesting vector $\bf{Q}^* $. Within this approach we can
predicted the behavior of the spin susceptibility at $\bQ^*$ and find it to be
is strikingly similar to the phenomenology of resonance peaks in high-T$_c$ and
heavy fermion superconductors. The energy of the resonance peak scales with
$T_{HO}$ $\omega_{res} \simeq 4 k_BT_{HO}$. We discuss observable consequences
spin resonance will have on neutron scattering and local density of states.",0903.2570v1
2012-11-08,A hybrid quantum circuit consisting of a superconducting flux qubit coupled to both a spin ensemble and a transmission-line resonator,"We propose an experimentally realizable hybrid quantum circuit for achieving
a strong coupling between a spin ensemble and a transmission-line resonator via
a superconducting flux qubit used as a data bus. The resulting coupling can be
used to transfer quantum information between the spin ensemble and the
resonator. In particular, in contrast to the direct coupling without a data
bus, our approach requires far less spins to achieve a strong coupling between
the spin ensemble and the resonator (e.g., three to four orders of magnitude
less). This proposed hybrid quantum circuit could enable a long-time quantum
memory when storing information in the spin ensemble, and allows the
possibility to explore nonlinear effects in the ultrastrong-coupling regime.",1211.1827v2
2013-03-18,Spin resonance in Luttinger liquid with spin-orbit interaction,"Spin-orbit interaction in quantum wires leads to a spin resonance at low
temperatures, even in the absence of an external dc magnetic field. We study
the effect of electron-electron interaction on the resonance. This interaction
is strong in quantum wires. We show that the electron-electron interaction
changes the shape of the resonance curve and produces an additional cusp at the
plasmon frequency. However, except for very strong electron-electron
interaction these changes are weak since this interaction by itself does not
break the spin-rotation symmetry that is violated weakly by the spin-orbit
interaction and external magnetic field.",1303.4149v2
2013-09-09,Real space Green's function approach to angle resolved resonant photoemission: spin polarization and circular dichroism in itinerant magnets,"A first principles approach, based on the real space multiple scattering
Green's function method, is presented for spin- and angle-resolved resonant
photoemission from magnetic surfaces. It is applied to the Fe(010) valence band
photoemission excited with circularly polarized X-rays around the Fe L3
absorption edge. When the photon energy is swept through the Fe 2p-3d
resonance, the valence band spectra are strongly modified in terms of absolute
and relative peak intensities, degree of spin-polarization and light
polarization dependence. New peaks in the spin-polarized spectra are identified
as spin-flip transitions induced by exchange decay of spin-mixed core-holes. By
comparison with single atom and band structure data, it is shown that both
intra-atomic and multiple scattering effects strongly influence the spectra. We
show how the different features linked to states of different orbital symmetry
in the d band are differently enhanced by the resonant effect. The appearance
and origin of circular dichroism and spin polarization are analyzed for
different geometries of light incidence and electron emission direction,
providing guidelines for future experiments.",1309.2335v1
2013-09-21,Fundamental limitations in spin-ensemble quantum memories for cavity fields,"Inhomogeneously broadened spin ensembles play an important role in
present-day implementation of hybrid quantum processing architectures. When
coupled to a resonator such an ensemble may serve as a multi-mode quantum
memory for the resonator field, and by employing spin-refocusing techniques the
quantum memory time can be extended to the coherence time of individual spins
in the ensemble. In the present paper we investigate such a memory protocol
capable of storing an unknown resonator-field state, and we examine separately
the various constituents of the protocol: the storage and read-out part, the
memory hold time with the spin ensemble and resonator field decoupled, and the
parts employing spin refocusing techniques. Using both analytical and numerical
methods we derive how the obtainable memory performance scales with various
physical parameters.",1309.5517v1
2013-11-29,Resonant optical pumping of a Mn spin in a strain free quantum dot,"We report on the spin properties of individual Mn atoms in II-VI
semiconductor strain free quantum dots. Strain free Mn-doped CdTe quantum dots
are formed by width fluctuations in thin quantum wells lattice matched on a
CdTe substrate. These quantum dots permit to optically probe and address any
spin state of a Mn atom in a controlled strain environment. The absence of
strain induced magnetic anisotropy prevents an optical pumping of the Mn spin
at zero magnetic field. Thus, a large photoluminescence is obtained under
resonant optical excitation of the exciton-Mn complex. An efficient optical
pumping of the coupled electronic and nuclear spins of the Mn is restored under
a weak magnetic field. The observed reduction of the resonant photoluminescence
intensity under magnetic field is well described by a model including the
hyperfine coupling and a residual crystal field splitting of the Mn atom.
Finally, we show that the second order correlation function of the resonant
photoluminescence presents a large photon bunching at short delay which is a
probe of the dynamics of coupled electronic and nuclear spins of the Mn atom.",1311.7622v1
2014-04-02,Ground-state cooling of a carbon nanomechanical resonator by spin-polarized current,"We study the nonequilibrium steady state of a mechanical resonator in the
quantum regime realized by a suspended carbon nanotube quantum dot contacted by
two ferromagnets. Because of the spin-orbit interaction and/or an external
magnetic field gradient, the spin on the dot couples directly to the flexural
eigenmodes. Accordingly, the nanomechanical motion induces inelastic spin flips
of the tunneling electrons. A spin-polarized current at finite bias voltage
causes either heating or active cooling of the mechanical modes. We show that
maximal cooling is achieved at resonant transport when the energy splitting
between two dot levels of opposite spin equals the vibrational frequency. Even
for weak electron-resonator coupling and moderate polarizations we can achieve
ground-state cooling with a temperature of the leads, for instance, of
$T=10\omega$.",1404.0485v3
2014-07-21,Spin-dependent recombination at arsenic donors in ion-implanted silicon,"Spin-dependent transport processes in thin near-surface doping regions
created by low energy ion implantation of arsenic in silicon are detected by
two methods, spin-dependent recombination (SDR) using microwave
photoconductivity and electrically detected magnetic resonance (EDMR)
monitoring the DC current through the sample. The high sensitivity of these
techniques allows the observation of the magnetic resonance in particular of As
in weak magnetic fields and at low resonance frequencies (40-1200 MHz), where
high-field-forbidden transitions between the magnetic substates can be observed
due to the mixing of electron and nuclear spin states. Several
implantation-induced defects are present in the samples studied and act as spin
readout partner. We explicitly demonstrate this by electrically detected
electron double resonance experiments and identify a pair recombination of
close pairs formed by As donors and oxygen-vacancy centers in an excited
triplet state (SL1) as the dominant spin-dependent process in As-implanted
Czochralski-grown Si.",1407.5534v1
2015-04-07,Quasiparticle Spin Resonance and Coherence in Superconducting Aluminium,"Spin/magnetisation relaxation and coherence times, respectively T_1 and T_2,
initially defined in the context of nuclear magnetic resonance (NMR), are
general concepts applicable to a wide range of systems, including quantum bits
[1-4]. At first glance, these ideas might seem to be irrelevant to conventional
Bardeen-Cooper-Schrieffer (BCS) superconductors, as the BCS superconducting
ground state is a condensate of Cooper pairs of electrons with opposite spins
(in a singlet state) [5]. It has recently been demonstrated, however, that a
non-equilibrium magnetisation can appear in the quasiparticle (i.e. excitation)
population of a conventional superconductor, with relaxation times on the order
of several nanoseconds [6-10]. This raises the question of the spin coherence
time of quasiparticles in superconductors and whether this can be measured
through resonance experiments analogous to NMR and electron spin resonance
(ESR). We have performed such measurements in aluminium and find a
quasiparticle spin coherence time of 95+/-20ps.",1504.01615v1
2016-05-23,Cooling a Mechanical Resonator with a Nitrogen-Vacancy Center Ensemble Using a Room Temperature Excited State Spin-Strain Interaction,"We propose a protocol to dissipatively cool a room temperature mechanical
resonator using a nitrogen-vacancy (NV) center ensemble. The spin ensemble is
coupled to the resonator through its orbitally-averaged excited state, which
has a spin-strain interaction that has not been previously characterized. We
experimentally demonstrate that the spin-strain coupling in the excited state
is $13.5\pm0.5$ times stronger than the ground state spin-strain coupling. We
then theoretically show that this interaction combined with a high-density spin
ensemble enables the cooling of a mechanical resonator from room temperature to
a fraction of its thermal phonon occupancy.",1605.07131v2
2019-11-18,Influence of non-equilibrium phonons on the spin dynamics of a single Cr atom,"We analyse the influence of optically generated non-equilibrium phonons on
the spin relaxation and effective spin temperature of an individual Cr atom
inserted in a quantum dot. Using a three pulses pump-probe technique, we show
that the spin relaxation measured in resonant optical pumping experiments
strongly depends on the optical excitation conditions. We observe for an
isolated Cr in the dark a heating time shorter than a few hundreds $ns$ after
an initial high power non-resonant excitation pulse. A cooling time larger than
a few tens of $\mu s$, independent on the excitation, is obtained in the same
experimental conditions. We show that a tunable spin-lattice coupling dependent
on the density of non-equilibrium phonons can explain the observed dynamics.
Low energy excitation conditions are found where the Cr spin states
S$_z$=$\pm$1 can be efficiently populated by a non-resonant optical excitation,
prepared and read-out by resonant optical pumping and conserved in the dark
during a few $\mu$s.",1911.07639v1
2017-05-26,Static and Dynamic Magnetic Properties of FeMn/Pt Multilayers,"Recently we have demonstrated the presence of spin-orbit toque in FeMn/Pt
multilayers which, in combination with the anisotropy field, is able to rotate
its magnetization consecutively from 0o to 360o without any external field.
Here, we report on an investigation of static and dynamic magnetic properties
of FeMn/Pt multilayers using combined techniques of magnetometry, ferromagnetic
resonance, inverse spin Hall effect and spin Hall magnetoresistance
measurements. The FeMn/Pt multilayer was found to exhibit ferromagnetic
properties, and its temperature dependence of saturation magnetization can be
fitted well using a phenomenological model by including a finite distribution
in Curie temperature due to subtle thickness variations across the multilayer
samples. The non-uniformity in static magnetic properties is also manifested in
the ferromagnetic resonance spectra, which typically exhibit a broad resonance
peak. A damping parameter of around 0.106 is derived from the frequency
dependence of ferromagnetic resonance linewidth, which is comparable to the
reported values for other types of Pt-based multilayers. Clear inverse spin
Hall signals and spin Hall magnetoresistance have been observed in all samples
below the Curie temperature, which corroborate the strong spin-orbit torque
effect observed previously.",1705.09423v1
2018-02-15,Strain-assisted optomechanical coupling of polariton condensate spin to a micromechanical resonator,"We report spin and intensity coupling of an exciton-polariton condensate to
the mechanical vibrations of a circular membrane microcavity. We optically
drive the microcavity resonator at the lowest mechanical resonance frequency
while creating an optically-trapped spin-polarized polariton condensate in
different locations on the microcavity, and observe spin and intensity
oscillations of the condensate at the vibration frequency of the resonator.
Spin oscillations are induced by vibrational strain driving, whilst the
modulation of the optical trap due to the displacement of the membrane causes
intensity oscillations in the condensate emission. Our results demonstrate
spin-phonon coupling in a macroscopically coherent condensate.",1802.05442v1
2017-06-06,Spinon magnetic resonance of quantum spin liquids,"We describe electron spin resonance in a quantum spin liquid with significant
spin-orbit coupling. We find that the resonance directly probes spinon
continuum which makes it an efficient and informative probe of exotic
excitations of the spin liquid. Specifically, we consider spinon resonance of
three different spinon mean-field Hamiltonians, obtained with the help of
projective symmetry group analysis, which model a putative quantum spin liquid
state of the triangular rare-earth antiferromagnet YbMgGaO4. The band of
absorption is found to be very broad and exhibit strong van Hove singularities
of single spinon spectrum as well as pronounced polarization dependence.",1706.01597v2
2021-08-02,Coherence properties of a spin in a squeezed resonator,"A promising venue for hybrid quantum computation involves the strong coupling
between impurity spins and superconducting resonators. One strategy to control
and enhance this coupling is to prepare the resonator in a non-classical state,
such as a squeezed state. In this work, we theoretically study the effects of
these states on the coherence properties of the spin. We develop an analytic
approach based on the Schrieffer-Wolf transformation that allows us to
quantitatively predict the coupling and the dephasing rate of the spin, and we
numerically confirm its validity. We find that squeezing can enhance the
coupling between the resonator and the spin. However, at the same time, it
amplifies the photon noise and enhances the spin decoherence. Our work
demonstrates a major impediment in using squeezing to reach the strong-coupling
limit.",2108.01091v1
2021-01-07,Nanoscale spin detection of copper ions using double electron-electron resonance at room temperature,"We report the nanoscale spin detection and electron paramagnetic resonance
(EPR) spectrum of copper (Cu$^{2+}$) ions via double electron-electron
resonance with single spins in diamond at room temperature and low magnetic
fields. We measure unexpectedly narrow EPR resonances with linewidths $\sim
2-3$ MHz from copper-chloride molecules dissolved in poly-lysine. We also
observe coherent Rabi oscillations and hyperfine splitting from single
Cu$^{2+}$ ions, which could be used for dynamic nuclear spin polarization and
higher sensitivity of spin detection. We interpret and analyze these
observations using both spin hamiltonian modeling of the copper-chloride
molecules and numerical simulations of the predicted DEER response, and obtain
a sensing volume $\sim (250 \text{nm})^3$. This work will open the door for
copper-labeled EPR measurements under ambient conditions in bio-molecules and
nano-materials.",2101.02650v2
2022-12-27,Optimizing tip-surface interactions in ESR-STM experiments,"Electron-spin resonance carried out with scanning tunneling microscopes
(ESR-STM) is a recently developed experimental technique that is attracting
enormous interest on account of its potential to carry out single-spin
on-surface resonance with subatomic resolution. Here we carry out a theoretical
study of the role of tip-adatom interactions and provide guidelines for
choosing the experimental parameters in order to optimize spin resonance
measurements. We consider the case of the Fe adatom on a MgO surface and its
interaction with the spin-polarized STM tip. We address three problems: first,
how to optimize the tip-sample distance to cancel the effective magnetic field
created by the tip on the surface spin, in order to carry out proper magnetic
field sensing. Second, how to reduce the voltage dependence of the surface-spin
resonant frequency, in order to minimize tip-induced decoherence due to voltage
noise. Third, we propose an experimental protocol to infer the detuning angle
between the applied field and the tip magnetization, which plays a crucial role
in the modeling of the experimental results.",2212.13471v1
2024-01-27,Spin--spin interaction and magnetic Feshbach resonances in collisions of high-spin atoms with closed-shell atoms,"We investigate interactions and ultracold collisions of high-spin but
spherical atoms with closed-shell atoms, focussing on the example of Cr with
Yb. Such a combination has only one potential energy curve but gives rise to a
substantial intra-atomic spin--spin interaction, which causes Feshbach
resonances due to rotationally excited states. We find such resonances are
guaranteed below 250 G and can reach widths of 10s of G in favorable
circumstances. We study the effect of hyperfine structure, which can create
additional wide resonances at low fields. Finally, we consider isotopic
substitution and find that this system is remarkably robust to unlucky
scattering lengths. Thus, this is a promising system for both molecule
formation and studying quantum mixtures including dipolar species.",2401.15350v1
2008-03-18,Kelvin Waves of Quantized Vortex Lines in Trapped Bose-Einstein Condensates,"We have theoretically investigated Kelvin waves of quantized vortex lines in
trapped Bose-Einstein condensates. Counterrotating perturbation induces an
elliptical instability to the initially straight vortex line, driven by a
parametric resonance between a quadrupole mode and a pair of Kelvin modes of
opposite momenta. Subsequently, Kelvin waves rapidly decay to longer
wavelengths emitting sound waves in the process. We present a modified Kelvin
wave dispersion relation for trapped superfluids and propose a simple method to
excite Kelvin waves of specific wave number.",0803.2574v2
2019-01-04,Unified view of nonlinear wave structures associated with whistler-mode chorus,"A range of nonlinear wave structures, including Langmuir waves, unipolar
electric fields and bipolar electric fields, are often observed in association
with whistler-mode chorus waves in the near-Earth space. We demonstrate that
the three seemingly different nonlinear wave structures originate from the same
nonlinear electron trapping process by whistler-mode chorus waves. The ratio of
the Landau resonant velocity to the electron thermal velocity controls the type
of nonlinear wave structures that will be generated.",1901.00953v3
2023-09-15,Gravitational waves from axion wave production,"We consider a scenario with axions/axion-like particles Chern-Simons gravity
coupling, such that gravitational waves can be produced directly from axion
wave parametric resonance in the early universe after inflation. This axion
gravity term is less constrained compared to the well-searched axion photon
coupling and can provide a direct and efficient production channel for
gravitational waves. Such stochastic gravitational waves can be detected by
either space/ground-based gravitational wave detectors or pulsar timing arrays
for a broad range of axion masses and decay constants.",2309.08407v2
2021-07-22,Spin-orbit torque control of spin waves in a ferromagnetic waveguide,"Spin-orbit torque (SOT) created by a spin current injected into a ferromagnet
by an adjacent heavy metal represents an efficient tool for the excitation and
manipulation of spin waves. Here we report the micromagnetic simulations
describing the influence of SOT on the propagation of spin waves in the
$\mathrm{W}/\mathrm{CoFeB}/\mathrm{MgO}$ nanostructure having
voltage-controlled magnetic anisotropy (VCMA). The simulations show that two
spin waves travelling in the opposite directions can be generated in the center
of the $\mathrm{CoFeB}$ waveguide via the modulation of VCMA induced by a
microwave voltage locally applied to the $\mathrm{MgO}$ nanolayer. The
amplitudes of these waves exponentially decrease with the propagation distance
with similar decay lengths of about 2.5 $\mu$m. In the presence of a direct
electric current injected into the $\mathrm{W}$ film beneath the waveguide
center, the decay lengths of two spin waves change in the opposite way owing to
different directions of the electric currents flowing in the underlying halves
of the $\mathrm{W}$ layer. Remarkably, above the critical current density
$J_\mathrm{W} \approx 2 \times 10^{10}$ A m$^{-2}$, SOT provides the
amplification of the spin wave propagating in one half of the waveguide and
strongly accelerates the attenuation of the wave travelling in the other half.
As a result, a long-distance spin-wave propagation takes place in a half of the
$\mathrm{CoFeB}$ waveguide only. Furthermore, by reversing the polarity of the
dc voltage applied to the heavy-metal layer one can change the propagation area
and switch the travel direction of the spin wave in the ferromagnetic
waveguide. Thus, the $\mathrm{W}/\mathrm{CoFeB}/\mathrm{MgO}$ nanostructure can
be employed as an electrically controlled magnonic device converting the
electrical input signal into a spin signal, which can be transmitted to one of
two outputs of the device.",2107.10795v2
2023-11-04,Evidence for Low-Level Dynamical Excitation in Near-Resonant Exoplanet Systems,"The geometries of near-resonant planetary systems offer a relatively pristine
window into the initial conditions of exoplanet systems. Given that
near-resonant systems have likely experienced minimal dynamical disruptions,
the spin-orbit orientations of these systems inform the typical outcomes of
quiescent planet formation, as well as the primordial stellar obliquity
distribution. However, few measurements have been made to constrain the
spin-orbit orientations of near-resonant systems. We present a
Rossiter-McLaughlin measurement of the near-resonant warm Jupiter TOI-2202 b,
obtained using the Carnegie Planet Finder Spectrograph (PFS) on the 6.5m
Magellan Clay Telescope. This is the eighth result from the Stellar Obliquities
in Long-period Exoplanet Systems (SOLES) survey. We derive a sky-projected 2D
spin-orbit angle $\lambda=26^{+12}_{-15}$ $^{\circ}$ and a 3D spin-orbit angle
$\psi=31^{+13}_{-11}$ $^{\circ}$, finding that TOI-2202 b - the most massive
near-resonant exoplanet with a 3D spin-orbit constraint to date - likely
deviates from exact alignment with the host star's equator. Incorporating the
full census of spin-orbit measurements for near-resonant systems, we
demonstrate that the current set of near-resonant systems with period ratios
$P_2/P_1\lesssim4$ is generally consistent with a quiescent formation pathway,
with some room for low-level ($\lesssim20^{\circ}$) protoplanetary disk
misalignments or post-disk-dispersal spin-orbit excitation. Our result
constitutes the first population-wide analysis of spin-orbit geometries for
near-resonant planetary systems.",2311.02478v1
2004-08-05,Spin Dynamics and Spin Transport,"Spin-orbit (SO) interaction critically influences electron spin dynamics and
spin transport in bulk semiconductors and semiconductor microstructures. This
interaction couples electron spin to dc and ac electric fields. Spin coupling
to ac electric fields allows efficient spin manipulating by the electric
component of electromagnetic field through the electric dipole spin resonance
(EDSR) mechanism. Usually, it is much more efficient than the magnetic
manipulation due to a larger coupling constant and the easier access to spins
at a nanometer scale. The dependence of the EDSR intensity on the magnetic
field direction allows measuring the relative strengths of the competing SO
coupling mechanisms in quantum wells. Spin coupling to an in-plane electric
field is much stronger than to a perpendicular field. Because electron bands in
microstructures are spin split by SO interaction, electron spin is not
conserved and spin transport in them is controlled by a number of competing
parameters, hence, it is rather nontrivial. The relation between spin
transport, spin currents, and spin populations is critically discussed.
Importance of transients and sharp gradients for generating spin magnetization
by electric fields and for ballistic spin transport is clarified.",0408119v1
2000-04-12,Resonant Spin-Dependent Tunneling in Spin-Valve Junctions in the Presence of Paramagnetic Impurities,"The tunnel magnetoresistance (TMR) of F/O/F magnetic junctions, (F's are
ferromagnetic layers and O is an oxide spacer) in the presence of magnetic
impurities within the barrier, is investigated. We assume that magnetic
couplings exist both between the spin of impurity and the bulk magnetization of
the neighboring magnetic electrode, and between the spin of impurity and the
spin of tunneling electron. Consequently, the resonance levels of the system
formed by a tunneling electron and a paramagnetic impurity with spin S=1, are a
sextet. As a result the resonant tunneling depends on the direction of the
tunneling electron spin. At low temperatures and zero bias voltage the TMR of
the considered system may be larger than TMR of the same structure without
paramagnetic impurities. It is calculated that an increase in temperature leads
to a decrease in the TMR amplitude due to excitation of spin-flip processes
resulting in mixing of spin up and down channels. It is also shown that
asymmetry in the location of the impurities within the barrier can lead to
asymmetry in $I(V)$ characteristics of impurity assisted current and two
mechanisms responsible for the origin of this effect are established. The first
one is due to the excitation of spin-flip processes at low voltages and the
second one arises from the shift of resonant levels inside the insulator layer
under high applied voltages.",0004198v2
2014-11-19,Coherent Control of a Nitrogen-Vacancy Center Spin Ensemble with a Diamond Mechanical Resonator,"Coherent control of the nitrogen-vacancy (NV) center in diamond's triplet
spin state has traditionally been accomplished with resonant ac magnetic fields
under the constraint of the magnetic dipole selection rule, which forbids
direct control of the $|-1>\leftrightarrow |+1>$ spin transition. We show that
high-frequency stress resonant with the spin state splitting can coherently
control NV center spins within this subspace. Using a bulk-mode mechanical
microresonator fabricated from single-crystal diamond, we apply intense ac
stress to the diamond substrate and observe mechanically driven Rabi
oscillations between the $|-1>$ and $|+1>$ states of an NV center spin
ensemble. Additionally, we measure the inhomogeneous spin dephasing time
($T_{2}^{*}$) of the spin ensemble using a mechanical Ramsey sequence and
compare it to the dephasing times measured with a magnetic Ramsey sequence for
each of the three spin qubit combinations available within the NV center ground
state. These results demonstrate coherent spin driving with a mechanical
resonator and could enable the creation of a phase-sensitive $\Delta$-system
within the NV center ground state.",1411.5325v2
2012-09-02,Nanoscale magnetic imaging of a single electron spin under ambient conditions,"The detection of ensembles of spins under ambient conditions has
revolutionized the biological, chemical, and physical sciences through magnetic
resonance imaging and nuclear magnetic resonance. Pushing sensing capabilities
to the individual-spin level would enable unprecedented applications such as
single molecule structural imaging; however, the weak magnetic fields from
single spins are undetectable by conventional far-field resonance techniques.
In recent years, there has been a considerable effort to develop nanoscale
scanning magnetometers, which are able to measure fewer spins by bringing the
sensor in close proximity to its target. The most sensitive of these
magnetometers generally require low temperatures for operation, but measuring
under ambient conditions (standard temperature and pressure) is critical for
many imaging applications, particularly in biological systems. Here we
demonstrate detection and nanoscale imaging of the magnetic field from a single
electron spin under ambient conditions using a scanning nitrogen-vacancy (NV)
magnetometer. Real-space, quantitative magnetic-field images are obtained by
deterministically scanning our NV magnetometer 50 nanometers above a target
electron spin, while measuring the local magnetic field using dynamically
decoupled magnetometry protocols. This single-spin detection capability could
enable single-spin magnetic resonance imaging of electron spins on the nano-
and atomic scales and opens the door for unique applications such as mechanical
quantum state transfer.",1209.0203v1
2013-07-10,"Scaling of spin Hall angle in 3d, 4d and 5d metals from Y3Fe5O12/metal spin pumping","Pure spin currents generated by spin pumping in ferromagnet/nonmagnet (FM/NM)
bilayers produce inverse spin Hall effect (ISHE) voltages in the NM, from which
spin pumping and transport characteristics of the NM can be extracted. Due to
its exceptionally low damping, Y3Fe5O12 (YIG) is an important and widely used
FM for microwave devices and ferromagnetic resonance (FMR) spin pumping. Here
we report systematic investigation of spin pumping from 20-nm thick YIG thin
films to a series of 3d, 4d and 5d normal metals (Cu, Ag, Ta, W, Pt and Au)
with various spin-orbit coupling strengths. From enhanced Gilbert damping
obtained from the frequency dependence of FMR linewidths and ISHE signals, the
spin Hall angles and YIG/NM interfacial spin mixing conductances are
quantitatively determined for these metals. The spin Hall angles largely vary
as the fourth power of the atomic number, corroborating the dominant role of
spin-orbit coupling across a broad range in the inverse spin Hall effect.",1307.2648v2
2013-07-10,Inverse Spin Hall Effect in NiFe / Normal Metal Bilayers,"Spin pumping in ferromagnets provides a source of pure spin currents. Via the
inverse spin Hall effect a spin current is converted into a charge current and
a corresponding detectable DC-voltage. The ratio of injected spin current to
resulting charge current is given by the spin Hall angle. However, the number
of experiments more or less equals the number of different values for spin Hall
angles, even for the most studied normal metal platinum. This publication
provides a full study of inverse spin Hall effect and anisotropic
magnetoresistance for different NiFe(Py) / normal metal bilayers using a
coplanar waveguide structure. Angle and frequency dependent measurements
strongly suggest that spin pumping and inverse spin Hall effect can be used to
quantify spin Hall angles only if certain conditions are met. Ruling out the
anisotropic magnetoresistance as a parasitic voltage generating effect
measurements of the inverse spin Hall effect in Py/Pt and Py/Au yield spin Hall
angles of 0.09 and 0.008 respectively. Furthermore, DC-voltages at
ferromagnetic resonance for Py/Pt are studied as a function of temperature and
the results are compared to theoretical models.",1307.2947v1
2015-11-01,Reciprocal spin Hall effects in conductors with strong spin-orbit coupling: a review,"Spin Hall effect and its inverse provide essential means to convert charge to
spin currents and vice versa, which serve as a primary function for spintronic
phenomena such as the spin-torque ferromagnetic resonance and the spin Seebeck
effect. These effects can oscillate magnetization or detect a thermally
generated spin splitting in the chemical potential. Importantly this conversion
process occurs via the spin-orbit interaction, and requires neither magnetic
materials nor external magnetic fields. However, the spin Hall angle, i.e., the
conversion yield between the charge and spin currents, depends severely on the
experimental methods. Here we discuss the spin Hall angle and the spin
diffusion length for a variety of materials including pure metals such as Pt
and Ta, alloys and oxides determined by the spin absorption method in a lateral
spin valve structure.",1511.00332v1
2018-04-23,Microscopic linear response theory of spin relaxation and relativistic transport phenomena in graphene,"We present a unified theoretical framework for the study of spin dynamics and
relativistic transport phenomena in disordered two-dimensional Dirac systems
with pseudospin-spin coupling. The formalism is applied to the paradigmatic
case of graphene with uniform Bychkov-Rashba interaction and shown to capture
spin relaxation processes and associated charge-to-spin interconversion
phenomena in response to generic external perturbations, including spin density
fluctuations and electric fields. A controlled diagrammatic evaluation of the
generalized spin susceptibility in the diffusive regime of weak spin-orbit
interaction allows us to show that the spin and momentum lifetimes satisfy the
standard Dyakonov-Perel relation for both weak (Gaussian) and resonant
(unitary) nonmagnetic disorder. Finally, we demonstrate that the spin
relaxation rate can be derived in the zero-frequency limit by exploiting the
SU(2) covariant conservation laws for the spin observables. Our results set the
stage for a fully quantum-mechanical description of spin relaxation in both
pristine graphene samples with weak spin-orbit fields and in graphene
heterostructures with enhanced spin-orbital effects currently attracting much
attention.",1804.08634v2
1996-07-25,Charge and Spin Response of the Spin--Polarized Electron Gas,"The charge and spin response of a spin--polarized electron gas is
investigated including terms beyond the random phase approximation. We evaluate
the charge response, the longitudinal and transverse spin response, and the
mixed spin--charge response self--consistently in terms of the susceptibility
functions of a non--interacting system. Exchange--correlation effects between
electrons of spin $\sigma$ and $\sigma^{'}$ are included following Kukkonen and
Overhauser, by using spin--polarization dependent generalized Hubbard local
field factors ${G_\sigma}^{\pm}$ and ${G_{\bar\sigma}}^{\pm}$. The general
condition for charge--density and spin--density--wave excitations of the system
is discussed.",9607178v1
2007-09-21,Spin-orbit mediated anisotropic spin interaction in interacting electron systems,"We investigate interactions between spins of strongly correlated electrons
subject to the spin-orbit interaction. Our main finding is that of a novel,
spin-orbit mediated anisotropic spin-spin coupling of the van der Waals type.
Unlike the standard exchange, this interaction does not require the wave
functions to overlap. We argue that this ferromagnetic interaction is important
in the Wigner crystal state where the exchange processes are severely
suppressed. We also comment on the anisotropy of the exchange between spins
mediated by the spin-orbital coupling.",0709.3521v2
2012-04-20,Composite Spin Liquid in Correlated Topological Insulator - Spin Liquid without Spin-Charge Separation,"In this paper, we found a new type of insulator - composite spin liquid which
can be regarded as a short range B-type topological spin-density-wave.
Composite spin liquid is topological ordered state beyond the classification of
traditional spin liquid states. The elementary excitations are the ""composite
electrons"" with both spin degree of freedom and charge degree of freedom,
together with topological spin texture. This topological state supports chiral
edge mode but no topological degeneracy.",1204.4552v1
2021-05-27,Tunneling spin current in a system with spin degeneracy,"We study theoretically spin current generation from a band insulator with PT
symmetry, which is associated with Zener tunneling in strong dc electric
fields. Each band in this system is doubly degenerate with opposite spins, but
spin rotational symmetry is not preserved in general. We consider the condition
for spin current generation in connection with the nature of the wave function,
which ultimately depends on a geometric quantity known as the shift vector.
From an analysis of a two-band model, we find that the shift vector is
necessary for spin current generation in a PT symmetric system. We also present
zigzag chain models that have shift vectors, and confirm from numerical
calculations that a nonzero tunneling spin current occurs in spin-degenerate
systems.",2105.13162v1
2020-01-21,Modulation theory and resonant regimes for dispersive shock waves in nematic liquid crystals,"A full analysis of all regimes for optical dispersive shock wave (DSW)
propagation in nematic liquid crystals is undertaken. These dispersive shock
waves are generated from step initial conditions for the optical field and are
resonant in that linear diffractive waves are in resonance with the DSW,
resulting in a resonant linear wavetrain propagating ahead of it. It is found
that there are six regimes, which are distinct and require different solution
methods. In previous studies, the same solution method was used for all
regimes, which does not yield solutions in full agreement with numerical
solutions. Indeed, the standard DSW structure disappears for sufficiently large
initial jumps. Asymptotic theory, approximate methods or Whitham modulation
theory are used to find solutions for these resonant dispersive shock waves in
a given regime. The solutions are found to be in excellent agreement with
numerical solutions of the nematic equations in all regimes. It is found that
for small initial jumps, the resonant wavetrain is unstable, but that it
stabilises above a critical jump height. It is additionally found that the DSW
is unstable, except for small jump heights for which there is no resonance and
large jump heights for which there is no standard DSW structure.",2001.07647v1
2021-01-02,Acoustic radiation-free surface phononic crystal resonator for in-liquid low-noise gravimetric detection,"Acoustic wave resonators are promising for gravimetric biosensing. However,
they generally suffer from strong acoustic radiation in liquid, which limits
their quality factor and increases their frequency noise. This article presents
an acoustic-radiation-free gravimetric biosensor based on a locally-resonant
surface phononic crystal (SPC) consisting of periodic high aspect ratio
electrodes to ad-dress the above issue. The acoustic wave generated in the SPC
is slower than the sound wave in water, hence preventing acoustic propagation
in the fluid and resulting in energy confinement near the electrode surface.
This energy confinement results in a significant quality factor improvement and
thus reduces the frequency noise. The proposed SPC resonator is numerically
studied by finite element analysis and experimentally implemented by an
electroplating based fabrication process. Experimental results show that the
SPC resonator exhibits an in-liquid quality factor 15 times higher than a
conventional Rayleigh wave resonator with a similar operating frequency. The
proposed radiation suppression method using SPC can also be applied in other
types of acoustic wave resonators. It can thus serve as a general technique for
boosting the in-liquid quality factor and the sensing performance of many
acoustic biosensors.",2101.00504v2
2021-11-09,The In Situ Signature of Cyclotron Resonant Heating,"The dissipation of magnetized turbulence is an important paradigm for
describing heating and energy transfer in astrophysical environments such as
the solar corona and wind; however, the specific collisionless processes behind
dissipation and heating remain relatively unconstrained by measurements. Remote
sensing observations have suggested the presence of strong temperature
anisotropy in the solar corona consistent with cyclotron resonant heating. In
the solar wind, in situ magnetic field measurements reveal the presence of
cyclotron waves, while measured ion velocity distribution functions have hinted
at the active presence of cyclotron resonance. Here, we present Parker Solar
Probe observations that connect the presence of ion-cyclotron waves directly to
signatures of resonant damping in observed proton-velocity distributions. We
show that the observed cyclotron wave population coincides with both flattening
in the phase space distribution predicted by resonant quasilinear diffusion and
steepening in the turbulent spectra at the ion-cyclotron resonant scale. In
measured velocity distribution functions where cyclotron resonant flattening is
weaker, the distributions are nearly uniformly subject to ion-cyclotron wave
damping rather than emission, indicating that the distributions can damp the
observed wave population. These results are consistent with active cyclotron
heating in the solar wind.",2111.05400v2
2004-07-28,"Comment on ""Exchange interaction parameters and adiabatic spin-wave spectra of ferromagnets: A 'renormalized magnetic force theorem'""","This is a comment on publication in Phys. Rev. Lett. 90, 087205 (2003):
``Exchange interaction parameters and adiabatic spin-wave spectra of
ferromagnets: A `renormalized magnetic force theorem'''",0407739v1
2017-12-02,Coherent excitation of heterosymmetric spin waves with ultrashort wavelengths,"In the emerging field of magnonics, spin waves are foreseen as signal
carriers for future spintronic information processing and communication
devices, owing to both the very low power losses and a high device
miniaturisation potential predicted for short-wavelength spin waves. Yet, the
efficient excitation and controlled propagation of nanoscale spin waves remains
a severe challenge. Here, we report the observation of high-amplitude,
ultrashort dipole-exchange spin waves (down to 80 nm wavelength at 10 GHz
frequency) in a ferromagnetic single layer system, coherently excited by the
driven dynamics of a spin vortex core. We used time-resolved x-ray microscopy
to directly image such propagating spin waves and their excitation over a wide
range of frequencies. By further analysis, we found that these waves exhibit a
heterosymmetric mode profile, involving regions with anti-Larmor precession
sense and purely linear magnetic oscillation. In particular, this mode profile
consists of dynamic vortices with laterally alternating helicity, leading to a
partial magnetic flux closure over the film thickness, which is explained by a
strong and unexpected mode hybridisation. This spin-wave phenomenon observed is
a general effect inherent to the dynamics of sufficiently thick ferromagnetic
single layer films, independent of the specific excitation method employed.",1712.00681v3
2014-06-11,Spin flip probability of electron due to torsional wave,"The probability of spin flip of an electron due to a torsional wave is
calculated. It is compared to the electromagnetic case, and ways to detect
torsion are discussed.",1406.2965v1
2016-11-17,Parallel pumping for magnon spintronics: Amplification and manipulation of magnon spin currents on the micron-scale,"Magnonics and magnon spintronics aim at the utilization of spin waves and
magnons, their quanta, for the construction of wave-based logic networks via
the generation of pure all-magnon spin currents and their interfacing with
electrical charge transport. The promise of efficient parallel data processing
and low power consumption renders this field one of the most promising research
areas in spintronics. In this context, the process of parallel parametric
amplification, i.e., the conversion of microwave photons into magnons at one
half of the microwave frequency, has proven to be a versatile tool. Its
beneficial and unique properties, such as frequency and mode-selectivity, the
possibility to excite spin waves in a wide wavevector range and the creation of
phase-correlated wave pairs, render it one of the key methods of spin-wave
generation and amplification.
  The application of parallel parametric amplification to micro- and
nanostructures is an important step towards the realization of magnonic
networks. This is motivated not only by the fact that amplifiers are an
important tool for the construction of any extended logic network but also by
the unique properties of parallel parametric amplification, such as a
phase-dependent amplification. Recently, the successful application of parallel
parametric amplification to metallic microstructures has been reported. It has
been demonstrated that parametric amplification provides an excellent tool to
generate and to amplify spin waves in these systems. In particular, the
amplification greatly benefits from the discreteness of the spin-wave spectra.
This opens up new, interesting routes of spin-wave amplification and
manipulation. In this Review, we give an overview over the recent developments
and achievements in this field.",1611.05893v1
2019-01-27,Observation of band narrowing and mode conversion in two-dimensional binary magnonic crystal,"We introduce a new type of binary magnonic crystal, where Ni$_{80}$Fe$_{20}$
nanodots of two different sizes are diagonally connected forming a unit and
those units are arranged in a square lattice. The magnetization dynamics of the
sample is measured by using time-resolved magneto-optical Kerr effect
microscope with varying magnitude and in-plane orientation ($\phi$) of the bias
magnetic field. Interestingly, at $\phi=0^{\circ}$, the spin-wave mode profiles
show frequency selective spatial localization of spin-wave power within the
array. With the variation of $\phi$ in the range $0^{\circ}<\phi\leq
45^{\circ}$, we observe band narrowing due to localized to extended spin-wave
mode conversion. Upon further increase of $\phi$, the spin-wave modes slowly
lose the extended nature and become fully localized again at 90$^{\circ}$. We
have extensively demonstrated the role of magnetostatic stray field
distribution on the rotational symmetries obtained for the spin-wave modes.
From micromagnetic simulations, we find that the dipole-exchange coupling
between the nano-dots leads to remarkable modifications of the spin-wave mode
profiles when compared with arrays of individual small and large dots.
Numerically, we also show that the physical connection between the nano-dots
provides more control points over the spin-wave propagation in the lattice at
different orientations of bias magnetic field. This new type of binary magnonic
crystal may find potential applications in magnonic devices such as spin-wave
waveguide, filter, coupler, and other on-chip microwave communication devices.",1901.09325v1
2022-06-30,Experimental Demonstration of a Spin-Wave Lens Designed with Machine Learning,"We present the design and experimental realization of a device that acts like
a spin-wave lens i.e., it focuses spin waves to a specified location. The
structure of the lens does not resemble any conventional lens design, it is a
nonintuitive pattern produced by a machine learning algorithm. As a spin-wave
design tool, we used our custom micromagnetic solver ""SpinTorch"" that has
built-in automatic gradient calculation and can perform backpropagation through
time for spin-wave propagation. The training itself is performed with the
saturation magnetization of a YIG film as a variable parameter, with the goal
to guide spin waves to a predefined location. We verified the operation of the
device in the widely used mumax3 micromagnetic solver, and by experimental
realization. For the experimental implementation, we developed a technique to
create effective saturation-magnetization landscapes in YIG by direct
focused-ion-beam irradiation. This allows us to rapidly transfer the nanoscale
design patterns to the YIG medium, without patterning the material by etching.
We measured the effective saturation magnetization corresponding to the FIB
dose levels in advance and used this mapping to translate the designed
scatterer to the required dose levels. Our demonstration serves as a proof of
concept for a workflow that can be used to realize more sophisticated spin-wave
devices with complex functionality, e.g., spin-wave signal processors, or
neuromorphic devices.",2207.00055v1
2001-03-30,Numerical computation of resonance poles in scattering theory,"We present a possible way of computing resonance poles and modes in
scattering theory. Numerical examples are given for the scattering of
electromagnetic waves by finite-size photonic crystals.",0103046v1
2004-10-08,Identification of Local Alfven Wave Resonances with Reflectometry as a Diagnostic Tool in Tokamaks,"Local Alfven wave (LAW) resonances are excited in tokamak plasmas by an
externally driven electro-magnetic field, with the frequency below the ion
cyclotron frequency, where using of the Alfven waves is assumed. Recently, wave
driven density fluctuations at the LAW resonance m=+/-1, N=+/-2 with few kW
power deposition and 4 MHz frequency were detected in TCABR (Bt =1.1T, q0 =1.1,
n0=1.4-2.0 10^{19}/ m^3) using a fixed frequency (32.4GHz) O-mode
reflectometer. Here, we show that combination of small power deposition in LAW
resonances, swept by plasma density variation or scanned with generator
frequencies, in combination with detection of the density fluctuations in the
LAW resonances by reflectometry can serve as diagnostic tool for identification
of the effective ion mass number Aef and q-profile in tokamaks. The idea is
based on the simultaneous detection of the position of m=+/-1 local AW
resonances, which are excited by M/N=+/-1/+/-2 antenna modes, and m=0 generated
by poloidal mode coupling effect in tokamaks. According to LAW dispersion, the
m=0 resonance depends only on the effective ion mass number and does not depend
on the q-profile. Then, using these data we can define q-value at the position
of m=+/-1 L AW resonances. Using TAE coils with even toroidal modes (N=2, 4,..)
and AW generator in the frequency band 0.6-1 MHz, an application of this method
to Joint European Torus (Bt=2.3T, q0 =1-1.3, n0=5-7 10^19/m^3) is demonstrated.",0410048v1
2013-04-08,Helicity amplitudes for photoexcitation of nucleon resonances off neutrons,"The helicity amplitudes $A^{1/2}_n$ and $A^{3/2}_n$ for the photoexcitation
of nucleon resonances off neutrons are determined in a multi-channel
partial-wave analysis.",1304.2177v1
2023-01-11,Traveling wave enantio-selective electron paramagnetic resonance,"We propose a novel method for enantio-selective electron paramagnetic
resonance spectroscopy based on magneto-chiral anisotropy. We calculate the
strength of this effect and propose a dedicated interferometer setup for its
observation.",2301.04755v1
2023-10-16,Direct observation of small scale capillary wave turbulence using high speed digital holographic microscopy,"It is now known that capillary waves driven upon a fluid interface by high
frequency ($>1$~MHz) ultrasound exhibit capillary wave turbulence: the
appearance of waves with phase and wavelength far removed from the excitation
signal that drives them. An important step towards understanding atomization
phenomena driven in this system, these capillary waves may now be studied using
high-speed digital holographic microscopy. We observe Zakharov-Kolmogorov weak
wave turbulence for a limited range of input power, and find broader turbulence
phenomena outside this range. We see discrete thresholds as the input power is
increased, where higher and higher frequency responses are driven in the
capillary waves with sudden onset between regimes. Here, we employ spatial
analysis to find one such extension of the capillary wave response to higher
frequencies, suggesting there is additional information in the spatial
distribution of the capillary wave that is rarely if ever measured. We verify
via frequency modulation that nonlinear resonance broadening is present, which
undermines the use of Faraday wave or parametric wave theories to characterize
these waves, important in the context of atomization which is not a Faraday
wave process.",2310.10840v1
1993-12-09,Spin-Wave-Spin-Wave Interaction and the Thermodynamics of the Heisenberg Spin Chain,"The low-temperature free energy of the spin S quantum Heisenberg
ferromagnetic chain in a strong magnetic field is obtained in a two-particle
approximation by using exact solution of two-spin-wave problem. The result is
beyond the perturbation theory because it incorporates the both bound and
scattering state contributions, and the scattering effect is essential as well
as the bound state one. In particular the main temperature renormalization of
an exchange constant is found to be linear in temperature instead $T^{3/2}$
corresponded to the perturbation theory result.",9312038v1
1994-08-02,Composite-Fermion Picture for the Spin-Wave Excitation in the fractional quantum Hall system,"Spin-wave excitation mode from the spin-polarized ground state in the
fractional quantum Hall liquid with odd fractions ($\nu=1/3,1/5$) numerically
obtained by the exact diagonalization of finite systems is shown to be
accurately described, for wavelengths exceeding the magnetic length, in terms
of the composite-fermion mean-field approximation for the spin-wave (magnon)
theory formulated in the spherical geometry. This indicates that the composite
picture extends to excited states, and also provides the spin stiffness in
terms of peculiar exchange interactions.",9408004v1
1997-12-01,Spin-wave series for quantum one-dimensional ferrimagnets,"Second-order spin-wave expansions are used to compute the ground-state energy
and sublattice magnetizations of the quantum one-dimensional Heisenberg
ferrimagnet with nearest-neighbor antiferromagnetic interactions and two types
of alternating sublattice spins $S_1>S_2$. It is found that in the extreme
quantum cases $(S_1,S_2)=(1,1/2)$, $(3/2,1)$, and $(3/2,1/2)$, the estimates
for the ground-state energy and sublattice magnetizations differ less than
0.03% for the energy and 0.2% for the sublattice magnetizations from the
recently published density matrix renormalization group numerical calculations.
  The reported results strongly suggest that the quantum Heisenberg
ferrimagnetic chains give another example of a low-dimensional quantum spin
system where the spin-wave approach demonstrates a surprising efficiency.",9712014v1
1998-03-02,Evolution of Hole and Spin Dynamics in High Temperature Superconductors within the Small Hole Density Limit of the t-J Model,"The evolution of hole and spin dynamics in high temperature superconductors
is studied within the self-consistent noncrossing approximation of the t-J
model in the small hole density limit. As the doping concentration is
increased, long-range electron correlations disappear rapidly and the
quasiparticle energy band becomes considerably narrow. At a small hole density
long-range antiferromagnetic order is destroyed leading to the inadequacy of
spin wave basis approximation near small wave vectors. Spin excitations near
the antiferromagnetic zone boundary are strongly renormalized and damped but
they are still well described within spin wave basis approximation.",9803016v1
1999-08-26,Magnons in real materials from density-functional theory,"We present an implementation of the adiabatic spin-wave dynamics of Niu and
Kleinman. This technique allows to decouple the spin and charge excitations of
a many-electron system using a generalization of the adiabatic approximation.
The only input for the spin-wave equations of motion are the energies and Berry
curvatures of many-electron states describing frozen spin spirals. The latter
are computed using a newly developed technique based on constrained
density-functional theory, within the local spin density approximation and the
pseudo-potential plane-wave method. Calculations for iron show an excellent
agreement with experiments.",9908386v1
2004-02-12,Spin Dynamics of Double-Exchange Manganites with Magnetic Frustration,"This work examines the effects of magnetic frustration due to competing
ferromagnetic and antiferromagnetic Heisenberg interactions on the spin
dynamics of the double-exchange model. When the local moments are non-colinear,
a charge-density wave forms because the electrons prefer to sit on lines of
sites that are coupled ferromagnetically. With increasing hopping energy, the
local spins become aligned and the average spin-wave stiffness increases. Phase
separation is found only within a narrow range of hopping energies. Results of
this work are applied to the field-induced jump in the spin-wave stiffness
observed in the manganite Pr$_{1-x}$Ca$_x$MnO$_3$ with $0.3 \le x \le 0.4$.",0402344v1
2006-06-15,Interplay between phase defects and spin polarization in the specific heat of the spin density wave compound (TMTTF)_2Br in a magnetic field,"Equilibrium heat relaxation experiments provide evidence that the ground
state of the commensurate spin density wave (SDW) compound (TMTTF)$_2$Br after
the application of a sufficient magnetic field is different from the
conventional ground state. The experiments are interpreted on the basis of the
local model of strong pinning as the deconfinement of soliton-antisoliton pairs
triggered by the Zeeman coupling to spin degrees of freedom, resulting in a
magnetic field induced density wave glass for the spin carrying phase
configuration.",0606403v1
2006-06-21,Quantum Dynamics of Spin Wave Propagation Through Domain Walls,"Through numerical solution of the time-dependent Schrodinger equation, we
demonstrate that magnetic chains with uniaxial anisotropy support stable
structures, separating ferromagnetic domains of opposite magnetization. These
structures, domain walls in a quantum system, are shown to remain stable if
they interact with a spin wave. We find that a domain wall transmits the
longitudinal component of the spin excitations only. Our results suggests that
continuous, classical spin models described by LLG equation cannot be used to
describe spin wave-domain wall interaction in microscopic magnetic systems.",0606549v1
2006-10-04,Spin-density induced by electromagnetic wave in two-dimensional electron gas,"We consider the magnetic response of a two-dimensional electron gas (2DEG)
with a spin-orbit interaction to a long-wave-length electromagnetic excitation.
We observe that the transverse electric field creates spin polarization
perpendicular to the 2DEG plane. The effect is more prominent in clean systems
with resolved spin-orbit-split subbands, and reaches maximum when the frequency
of the wave matches the subband splitting at the Fermi momentum. The relation
of this effect to the spin-Hall effect is discussed.",0610124v4
2007-06-02,Standing Spin Waves in an Antiferromagnetic Molecular Cr6 Horseshoe,"The antiferromagnetic molecular finite chain Cr6 was studied by inelastic
neutron scattering. The observed magnetic excitations at 2.6 and 4.3 meV
correspond, due to the open boundaries of a finite chain, to standing spin
waves. The determined energy spectrum revealed an essentially classical spin
structure. Hence, various spin-wave theories were investigated in order to
assess their potential for describing the elementary excitations of finite spin
systems.",0706.0247v1
2009-05-20,Berry phase and topological spin transport in the chiral d-density wave state,"In this paper we demonstrate the possibility of dissipationless spin
transport in the chiral d-density wave state, by the sole application of a
uniform Zeeman field gradient. The occurrence of these spontaneous spin
currents is attributed to the parity (${\cal P}$) and time-reversal (${\cal
T}$) violation induced by the $d_{xy}+id_{x^2-y^2}$ density wave order
parameter. We calculate the spin Hall conductance and reveal its intimate
relation to the Berry phase which is generated when the Zeeman field is applied
adiabatically. Finally, we demonstrate that in the zero temperature and doping
case, the spin Hall conductance is quantized as it becomes a topological
invariant.",0905.3228v1
2009-11-04,Spin induced nonlinearities in the electron MHD regime,"We consider the influence of the electron spin on the nonlinear propagation
of whistler waves. For this purpose a recently developed electron two-fluid
model, where the spin up- and down populations are treated as different fluids,
is adapted to the electron MHD regime. We then derive a nonlinear Schrodinger
equation for whistler waves, and compare the coefficients of nonlinearity with
and without spin effects. The relative importance of spin effects depend on the
plasma density and temperature as well as the external magnetic field strength
and the wave frequency. The significance of our results to various plasmas are
discussed.",0911.0803v1
2010-05-14,The effect of spin magnetization in the damping of electron plasma oscillations,"The effect of spin of particles in the propagation of plasma waves is studied
using a semi-classical kinetic theory for a magnetized plasma. We focus in the
simple damping effects for the electrostatic wave modes besides Landau damping.
Without taking into account more quantum effects than spin contribution to
Vlasov's equation, we show that spin produces a new damping or instability
which is proportional to the zeroth order magnetization of the system. This
correction depends on the electromagnetic part of the wave which is coupled
with the spin vector.",1005.2573v1
2011-02-27,Cauchy-Born rule and spin density wave for the spin-polarized Thomas-Fermi-Dirac-von Weizsacker model,"The electronic structure (electron charges and spins) of a perfect crystal
under external magnetic field is analyzed using the spin-polarized
Thomas-Fermi-Dirac-von Weizsacker model. An extension of the classical
Cauchy-Born rule for crystal lattices is established for the electronic
structure under sharp stability conditions on charge density wave and spin
density wave. A Landau-Lifschitz type micromagnetic energy functional is
derived.",1102.5545v1
2011-03-12,Effective field theories and spin-wave excitations in helical magnets,"We consider two classes of helical magnets. The first one has magnetic
ordering close to antiferromagnet and the second one has magnetic ordering
close to ferromagnet. The first case is relevant to cuprate superconductors and
the second case is realized in FeSrO$_3$ and FeCaO$_3$. We derive the effective
field theories for these cases and calculate corresponding excitation spectra.
We demonstrate that the ""hourglass"" spin-wave dispersion observed
experimentally in cuprates is a fingerprint of the ""antiferromagnetic spin
spiral state"". We also show that quantum fluctuations are important for the
""ferromagnetic spin spiral"", they influence qualitative features of the
spin-wave dispersion.",1103.2422v1
2011-10-18,Life times and chirality of spin-waves in antiferromagnetic and ferromagnetic FeRh: time depedent density functional theory perspective,"The study of the spin excitations in antiferromagnetic (AFM) and
ferromagnetic (FM) phases of FeRh is reported. We demonstrate that although the
Fe atomic moments are well defined there is a number of important phenomena
absent in the Heisenberg description: Landau damping of spin waves, large Rh
moments induced by the AFM magnons, the formation of the optical magnons
terminated by Stoner excitations. We relate the properties of the spin-wave
damping to the features of the Stoner continuum and compare the chirality of
the spin excitations in AFM, FM and paramagnetic (PM) systems.",1110.3913v1
2012-01-17,Spin wave excitation in magnetic insulators by spin-transfer torque,"We study the excitation of spin waves in magnetic insulators by the
current-induced spin-transfer torque. We predict preferential excitation of
surface spin waves induced by an easy-axis surface anisotropy with critical
current inversely proportional to the penetration depth and surface anisotropy.
The surface modes strongly reduce the critical current and enhance the
excitation power of the current-induced magnetization dynamics.",1201.3442v1
2012-08-17,Spin-torque effect on spin wave modes in magnetic nanowires,"The interaction between a spin polarized dc electrical current and spin wave
modes of a cylindrical nanowire is investigated in this report. We found that
close to the critical current, the uniform mode is suppressed, while the edge
mode starts to propagate into the sample. When the current exceeds the critical
value, this phenomenon is even more accentuated. The edge mode becomes the
uniform mode of the nanowire. The higher spin wave modes are slowly pushed away
by the current until the propagating mode remains.",1208.3661v1
2013-12-23,Acoustic parametric pumping of spin waves,"Recent experiments demonstrated generation of spin currents by ultrasound. We
can understand this acoustically induced spin pumping in terms of the coupling
between magnetization and lattice waves. Here we study the parametric
excitation of magnetization by longitudinal acoustic waves and calculate the
acoustic threshold power. The induced magnetization dynamics can be detected by
the spin pumping into an adjacent normal metal that displays the inverse spin
Hall effect.",1312.6499v1
2014-04-18,Validity of spin wave theory for the quantum Heisenberg model,"Spin wave theory is a key ingredient in our comprehension of quantum spin
systems, and is used successfully for understanding a wide range of magnetic
phenomena, including magnon condensation and stability of patterns in dipolar
systems. Nevertheless, several decades of research failed to establish the
validity of spin wave theory rigorously, even for the simplest models of
quantum spins. A rigorous justification of the method for the three-dimensional
quantum Heisenberg ferromagnet at low temperatures is presented here. We derive
sharp bounds on its free energy by combining a bosonic formulation of the model
introduced by Holstein and Primakoff with probabilistic estimates and operator
inequalities.",1404.4717v1
2016-04-04,On the distribution of stellar-sized black hole spins,"Black hole spin will have a large impact on searches for gravitational waves
with advanced detectors. While only a few stellar mass black hole spins have
been measured using X-ray techniques, gravitational wave detectors have the
capacity to greatly increase the statistics of black hole spin measurements. We
show what we might learn from these measurements and how the black hole spin
values are influenced by their formation channels.",1604.00778v1
2018-04-27,Spin Waves in Quantum Gases --- The Quality Factor of the Identical Spin Rotation Effect,"Our recent experimental work on electron spin waves in atomic hydrogen gas
has prompted a revisit of the theory of the Identical Spin Rotation Effect
(ISRE). A key characteristic determining the properties of the spin waves is
the quality factor of ISRE. Unfortunately, calculating this quality factor
takes some toil. In this paper we summarize some results of the ISRE theory in
dilute gases. We also derive asymptotic formulae for the quality factor and
examine their accuracy for hydrogen and $^3$He.",1804.10431v1
2015-05-16,Dynamics of a macroscopic spin qubit in spin-orbit coupled Bose-Einstein condensates,"We consider a macroscopic spin qubit based on spin-orbit coupled
Bose-Einstein condensates, where, in addition to the spin-orbit coupling, spin
dynamics strongly depends on the interaction between particles. The evolution
of the spin for freely expanding, trapped, and externally driven condensates is
investigated. For condensates oscillating at the frequency corresponding to the
Zeeman splitting in the synthetic magnetic field, the spin Rabi frequency does
not depend on the interaction between the atoms since it produces only internal
forces and does not change the total momentum. However, interactions and
spin-orbit coupling bring the system into a mixed spin state, where the total
spin is inside rather than on the Bloch sphere. This greatly extends the
available spin space making it three-dimensional, but imposes limitations on
the reliable spin manipulation of such a macroscopic qubit. The spin dynamics
can be modified by introducing suitable spin-dependent initial phases,
determined by the spin-orbit coupling, in the spinor wave function.",1505.04301v1
2014-08-19,Towards the explicit computation of Bohm velocities associated to N-electron wave-functions with arbitrary spin-orientations,"The direct solution of the many-particle Schr\""odinger equation is
computationally inaccessible for more than very few electrons. In order to
surpass this limitation, one of the authors [X. Oriols, Phys. Rev. Lett. 2007,
98 (066803)] has recently proposed a new model to study electron-electron
correlations from Bohm trajectories associated to time-dependent wave-packets
solutions of pseudo single-particle Schr\""odinger equations. In the
aforementioned paper only the orbital exchange interaction is considered
assuming that all electrons have the same spin orientation. Then, the
many-particle wave function is a complex Slater determinant of the
single-particle wave-packets. In the present work the previous formalism is
extended to study many-particle wave functions where the electrons have
different spin orientations.The main difficulty to treat N different electron
spin orientations with time-dependent wave-packets is that one must study all
the possible N!N! products of permutations among spin states. To overcome this
computationally inaccessible problem, in this article the total wave function
is treated as a separated product of two many-particle wave functions, the
first with spin up and the second with spin down. In order to numerically
justify this approximation, the Bohm velocity in different antisymmetric total
wave-function scenarios is computed. The computational results confirms the
accurate validity of our approximation under a large number of cases.",1408.4346v1
2019-12-20,Slow-wave based magnonic diode,"Spin waves, the collective excitations of the magnetic order parameter, and
magnons, the associated quasiparticles, are envisioned as possible data
carriers in future wave-based computing architectures. On the road towards
spin-wave computing, the development of a diode-like device capable of
transmitting spin waves in only one direction, thus allowing controlled signal
routing, is an essential step. Here, we report on the design and experimental
realization of a microstructured magnonic diode in a ferromagnetic bilayer
system. Effective unidirectional propagation of spin waves is achieved by
taking advantage of nonreciprocities produced by dynamic dipolar interactions
in transversally magnetized media, which lack symmetry about their horizontal
midplane. More specifically, dipolar-induced nonreciprocities are used to
engineer the spin-wave dispersion relation of the bilayer system so that the
group velocity is reduced to very low values for one direction of propagation,
and not for the other, thus producing unidirectional slow spin waves. Brillouin
light scattering and propagating spin-wave spectroscopy are used to demonstrate
the diode-like behavior of the device, the composition of which was previously
optimized through micromagnetic simulations. simulations.",1912.09735v1
2015-08-06,Photoproduction of ω Mesons off the Proton,"The differential cross sections and unpolarized spin-density matrix elements
for the reaction $\gamma p\to p\omega$ were measured using the CBELSA/TAPS
experiment for initial photon energies ranging from the reaction threshold to
2.5 GeV. These observables were measured from the radiative decay of the
$\omega$ meson, $\omega\to\pi^0\gamma$. The cross sections cover the full
angular range and show the full extent of the $t$-channel forward rise. The
overall shape of the angular distributions in the differential cross sections
and unpolarized spin-density matrix elements are in fair agreement with
previous data. In addition, for the first time, a beam of linearly-polarized
tagged photons in the energy range from 1150 MeV to 1650 MeV was used to
extract polarized spin-density matrix elements.
  These data were included in the Bonn-Gatchina partial wave analysis (PWA).
The dominant contribution to $\omega$ photoproduction near threshold was found
to be the $3/2^+$ partial wave, which is primarily due to the sub-threshold
$N(1720)\,3/2^+$ resonance. At higher energies, pomeron-exchange was found to
dominate whereas $\pi$-exchange remained small. These $t$-channel contributions
as well as further contributions from nucleon resonances were necessary to
describe the entire dataset: the $1/2^-$, $3/2^-$, and $5/2^+$ partial waves
were also found to contribute significantly.",1508.01483v1
2006-02-02,Design of Q-Band loop-gap resonators at frequencies 34-36 GHz for single electron spin spectroscopy in semiconductor nanostructures,"We report on the design of loop-gap resonators (LGR) operating in the
frequency range 34-36 GHz with the goal to achieve single electron spin
resonance (ESR) in quantum dot nanostructures. We present a comprehensive study
of the magnetic field strength and the spatial distribution of the electric and
magnetic fields in the resonator by means of experiments and numerical
simulations.",0602058v1
2006-04-05,Current-driven resonant excitation of magnetic vortex,"A magnetic vortex core in a ferromagnetic circular nanodot has a resonance
frequency originating from the confinement of the vortex core. By the
micromagnetic simulation including the spin-transfer torque, we show that the
vortex core can be resonantly excited by an AC (spin-polarized) current through
the dot and that the resonance frequency can be tuned by the dot shape. The
resistance measurement under the AC current successfully detects the resonance
at the frequency consistent with the simulation.",0604123v1
2007-03-22,Resonant tunneling diode with spin polarized injector,"We investigate the current-voltage characteristics of a II-VI semiconductor
resonant-tunneling diode coupled to a diluted magnetic semiconductor injector.
As a result of an external magnetic field, a giant Zeeman splitting develops in
the injector, which modifies the band structure of the device, strongly
affecting the transport properties. We find a large increase in peak amplitude
accompanied by a shift of the resonance to higher voltages with increasing
fields. We discuss a model which shows that the effect arises from a
combination of three-dimensional incident distribution, giant Zeeman spin
splitting and broad resonance linewidth.",0703574v1
2001-06-20,Photo-production of Nucleon Resonances and Nucleon Spin Structure Function in the Resonance Region,"The photo-production of nucleon resonances is calculated based on a chiral
constituent quark model including both relativistic corrections H{rel} and
two-body exchange currents, and it is shown that these effects play an
important role. We also calculate the first moment of the nucleon spin
structure function g1 (x,Q^2) in the resonance region, and obtain a
sign-changing point around Q^2 ~ 0.27 {GeV}^2 for the proton.",0106225v2
2002-04-16,"On the spin, parity and nature of the $Ξ(1620)$ resonance","Using a unitary extension of chiral perturbation theory with a lowest-order
s-wave SU(3) chiral Lagrangian we study low-energy meson-baryon scattering in
the strangeness $S=-2$ sector. A scattering-matrix pole is found around 1606
MeV which corresponds to an s-wave $\Xi$ resonance with $J^P=1/2^-$. We
identify this resonance with the $\Xi(1620)$ state, quoted in the Particle Data
Book with $I=1/2$ but with unknown spin and parity. The addition of the $S=-2$
state to the recently computed $\Lambda(1670)$, $\Sigma(1620)$ and N(1535)
states completes the octet of $J^P=1/2^-$ resonances dynamically generated in
this chiral unitary approach.",0204044v1
2005-05-30,Target Normal Spin Asymmetry of the Elastic ep-Scattering at Resonance Energy,"We study the target normal spin asymmetry for the reaction $ep \to ep$ at
electron energy up to few GeV in the laboratory frame. The asymmetry is
proportional to the imaginary part of the reaction scattering amplitude. To
estimate the imaginary part of the amplitude we use the unitarity relation and
saturate the intermediate hadron states by the proton and resonances from the
first, second and third resonance regions. The resonance electromagnetic
transition amplitudes, needed to evaluate the asymmetry, are taken from
experiment.",0505079v2
2010-06-07,Bethe-Salpeter equations for the collective modes of the $t-U-V-J$ model with d-wave pairing,"The Bethe-Salpeter equations for the collective modes of a $t$-$U$-$V$-$J$
model are used to analyze the resonance peak observed at $\bf{Q}=(\pi,\pi)$ in
neutron scattering experiments on the cuprates. We assume that the resonance
emerges due to the mixing between the spin channel and 19 other channels. We
have calculated the energy of the lowest mode of the extended Hubbard model
($J=0$) vs the on-site repulsive interaction $U$, as well as the $UJ$ lines in
the interaction parameter space which are consistent with the ARPES data and
reproduces the resonance peak at 40 meV in Bi2212 compound. We find that the
resonance is predominantly a spin exciton.",1006.1388v1
2010-07-16,Controlling phase separation of binary Bose-Einstein condensates via mixed-spin-channel Feshbach resonance,"We investigate controlled phase separation of a binary Bose-Einstein
condensate (BEC) in the proximity of mixed-spin-channel Feshbach resonance in
the |F = 1, mF = +1> and |F = 2,mF = -1> states of 87Rb at a magnetic field of
9.10 G. Phase separation occurs on the lower magnetic-field side of the
Feshbach resonance while the two components overlap on the higher
magnetic-field side. The Feshbach resonance curve of the scattering length is
obtained from the shape of the atomic cloud by comparison with the numerical
analysis of coupled Gross-Pitaevskii equations.",1007.2690v1
2011-12-05,Boundary Resonances in S = 1/2 Antiferromagnetic Chains under a Staggered Field,"We develop a boundary field theory approach to electron spin resonance in
open $S=1/2$ Heisenberg antiferromagnetic chains with an effective staggered
field. In terms of the sine Gordon effective field theory with boundaries,we
point out the existence of boundary bound states of elementary excitations, and
modification of the selection rules at the boundary. We argue that several
""unknown modes"" found in electron spin resonance experiments on KCuGaF$_6$ [I.
Umegaki et al., Phys. Rev. B 79, 184401 (2009)] and Cu-PM [S. A. Zvyagin et
al., Phys. Rev. Lett. 93, 027201 (2004)] can be understood as boundary
resonances introduced by these effects.",1112.1088v2
2021-01-27,Robust photon-mediated entangling gates between quantum dot spin qubits,"Significant experimental advances in single-electron silicon spin qubits have
opened the possibility of realizing long-range entangling gates mediated by
microwave photons. Recently proposed iSWAP gates, however, require tuning qubit
energies into resonance and have limited fidelity due to charge noise. We
present a novel photon-mediated cross-resonance gate that is consistent with
realistic experimental capabilities and requires no resonant tuning.
Furthermore, we propose gate sequences capable of suppressing errors due to
quasistatic noise for both the cross-resonance and iSWAP gates.",2101.11579v1
2020-08-27,Odd-frequency pair density wave correlations in underdoped cuprates,"Pair density waves, identified by Cooper pairs with finite center-of-mass
momentum, have recently been observed in copper oxide based high T$_\textrm{c}$
superconductors (cuprates). A charge density modulation or wave is also
ubiquitously found in underdoped cuprates. Within a general mean-field one-band
model we show that the coexistence of charge density waves and uniform
superconductivity in $d$-wave superconductors like cuprates, generates an
odd-frequency spin-singlet pair density wave, in addition to the even-frequency
counterparts. The strength of the induced odd-frequency pair density wave
depends on the modulation wave vector of the charge density wave, with the
odd-frequency pair density waves even becoming comparable to the even-frequency
ones in parts of the Brillouin zone. We show that a change in the modulation
wave vector of the charge density wave from bi-axial to uni-axial, can enhance
the odd-frequency component of the pair density waves. Such a coexistence of
superconductivity and uni-axial charge density wave has already been
experimentally verified at high magnetic fields in underdoped cuprates. We
further discuss the possibility of an odd-frequency spin-triplet pair density
wave generated in the coexistence regime of superconductivity and spin density
waves, applicable to the iron-based superconductors. Our work thus presents a
route to bulk odd-frequency superconductivity in high T$_c$ superconductors.",2008.12021v2
2007-04-08,Phenomenological theory of spin excitations in La- and Y-based cuprates,"Motivated by recent inelastic neutron scattering (INS) experiments on
La-based cuprates and based on the fermiology theories, we study the spin
susceptibility for La-based (e.g., La$_{2-x}$Sr$_x$CuO$_4$) and Y-based (e.g.,
YBa$_2$Cu$_3$O$_y$) cuprates, respectively. The spin excitation in
YBa$_2$Cu$_3$O$_y$ is dominated by a sharp resonance peak at the frequency 40
meV in the superconducting state. Below and above the resonance frequency, the
incommensurate (IC) peaks develop and the intensity of the peaks decreases
dramatically. In the normal state, the resonant excitation does not occur and
the IC peaks are merged into commensurate ones. The spin excitation of
La$_{2-x}$Sr$_x$CuO$_4$ is significantly different from that of Y-based ones,
namely, the resonance peak does not exist due to the decreasing of the
superconducting gap and the presence of the possible spin-stripe order. The
spectra are only enhanced at the expected resonance frequency (about 18 meV)
while it is still incommensurate. On the other hand, another frequency scale at
the frequency 55 meV is also revealed, namely the spectra are commensurate and
local maximum at this frequency. We elaborate all the results based on the
Fermi surface topology and the d-wave superconductivity, and suggest that the
spin-stripe order be also important in determining the spin excitation of
La-based cuprates. A coherent picture for the spin excitations is presented for
Y-based and La-based cuprates.",0704.1016v1
2018-06-20,Teetering Stars: Resonant Excitation of Stellar Obliquities by Hot and Warm Jupiters with External Companions,"Stellar spin-orbit misalignments (obliquities) in hot Jupiter systems have
been extensively probed. Such obliquities may reveal clues about hot Jupiter
dynamical histories. Common explanations for generating obliquities include
high-eccentricity migration and primordial disk misalignment. This paper
investigates another mechanism for producing stellar spin-orbit misalignments
in systems hosting a close-in planet with an external, modestly inclined
companion. Spin-orbit misalignment may be excited due to a secular resonance,
occurring when the precession rate of the stellar spin axis (driven by the
inner planet) becomes comparable to the nodal precession rate of the inner
planet (driven by the companion). Due to the spin-down of the host star via
magnetic braking, this resonance may be achieved during the star's
main-sequence lifetime for a wide range of planet masses and orbital
architectures. Obliquity excitation is accompanied by a decrease in mutual
inclination between the inner planet and perturber, and can thus erase high
inclinations. For hot Jupiters, the stellar spin axis is strongly coupled to
the orbital axis, and obliquity excitation by a giant planet companion requires
a strong perturber, usually located within 1-2 AU. For warm Jupiters, the spin
and orbital axes are more weakly coupled, and the resonance may be achieved for
distant giant planet perturbers (at several to tens of AU). Since warm Jupiters
have a high occurrence rate of distant planetary companions with appropriate
properties for resonant obliquity excitation, stellar obliquities in warm
Jupiter systems may be common, particularly for warm Jupiters orbiting cool
stars that have undergone significant spin-down.",1806.07892v2
2021-05-19,"Determination of the spin Hall angle by the inverse spin Hall effect, device level ferromagnetic resonance, and spin torque ferromagnetic resonance: a comparison of methods","The spin torque ferromagnetic resonance (STFMR) is one of the popular methods
for measurement of the spin Hall angle (SHA). However, in order to accurately
determine SHA from STFMR measurements, the acquired data must be carefully
analyzed: The resonance linewidth should be determined to an accuracy of a
fraction of an Oe, while the dynamical interaction leading to the measured
response consists of the conventional field-induced ferromagnetic resonance
(FMR), spin-torque induced FMR, and of the inverse spin Hall effect (ISHE).
Additionally, the signal often deteriorates when DC current is passed through
the device. In this work we compare the STFMR method with two other FMR-based
methods that are used to extract SHA. The first is a device-level FMR and the
second is based on the ISHE. We identify artefacts that are caused by the noise
floor of the instrumentation that make the measurement of SHA illusive even
when the signal to noise ratio seems to be reasonable. Additionally, we
estimate a 10% error in SHA that results from neglecting the magnetic
anisotropies as in conventional measurements. Overall, we find the STFMR to be
the most robust of the three methods despite the complexity of the interaction
taking place therein. The conclusions of our work lead to a more accurate
determination of SHA and will assist in the search of novel materials for
energy efficient spin-based applications.",2105.09023v1
2012-07-20,Thermal evolution of the full three-dimensional magnetic excitations in the multiferroic BiFeO3,"The idea of embedding and transmitting information within the fluctuations of
the magnetic moments of spins (spin waves) has been recently proposed and
experimentally tested. The coherence of spin waves, which describes how well
defined these excitations are, is of course vital to this process, and themost
significant factor that affects the spin-wave coherence is temperature. Here we
present neutron inelastic scattering measurements of the full threedimensional
spin-wave dispersion in BiFeO3, which is one of the most promising functional
multiferroic material, for temperatures from 5K to 700K. Despite the presence
of strong electromagnetic coupling, the magnetic excitations behave like
conventional magnons over all parts of the Brillouin zone. At low temperature
the spin-waves are well-defined coherent modes, described by a classical model
for a G-type antiferromagnet. A spin-wave velocity softening is already present
at room temperature, and more pronounced damping occurs as the magnetic
ordering temperature TN \sim 640K is approached. In addition, a strong
hybridization of the Fe 3d and O 2p states is found to modify the distribution
of the spin-wave spectral weight significantly, which implies that the spins
are not restricted to the Fe atomic sites as previously believed.",1207.5078v1
2018-12-26,Discretized dynamics of exchange spin wave bulk and edge modes in honeycomb nanoribbons with armchair edge boundaries,"We develop a field theory to study the dynamics of long wavelength exchange
spin wave excitations on honeycomb nanoribbons characterized by armchair edge
boundaries and the N\'eel antiferromagnetic ordering state. Appropriate
boundary conditions are established by requiring that the bulk and edge spins
precess with the same frequency for any given spin wave eigenmode in these
systems. A set of characteristic boundary equations, common for bulk and edge
spin wave modes, are hence derived. The equations of motion for the spin
dynamics are then solved to determine the propagating and evanescent exchange
spin wave modes. We prove in general that the bulk spin wave dynamics is
discretized due to the finite width of the nanoribbon. For an isotropic
magnetic nanoribbon, the Dirac cone is reduced to a single linear dispersion
curve due to this discretization. The number and wavelengths of allowed bulk
modes for isotropic and anisotropic nanoribbons are determined from the derived
characteristic boundary equations. As witnessed by our numerical results for
different examples it is shown that the characteristics of these modes depend
on the width of the nanoribbon and its antiferromagnetic anisotropy. Further,
anisotropic nanoribbons, even those with the slightest anisotropy, present
evanescent modes with non-linear dispersion relations. The spatial variation of
the amplitudes of the evanescent exchange spin waves across the finite widths
of the nanoribbons, is found to be strongly dependent on the system magnetic
anisotropy and its width. The developed theoretical approach is general and can
be applied for nanoribbons with all types of boundary edges.",1812.10204v2
2018-09-24,Secular Resonance Between Iapetus and the Giant Planets,"Using numerical integrations, we find that the orbital eccentricity of
Saturn's moon Iapetus undergoes prominent multi-Myr oscillations. We identify
the responsible resonant argument to be
$\varpi-\varpi_{g5}+\Omega-\Omega_{eq}$, with the terms being the longitudes of
pericenter of Iapetus and planetary secular mode $g_5$, Iapetus's longitude of
the node and Saturn's equinox. We find that this argument currently (on a
$10^7$~yr timescale) appears to librate with a very large amplitude. On longer
timescales, the behavior of this resonant angle is strongly dependent on the
resonant interaction between Saturn's spin axis and the planetary mode $f_8$,
with long-term secular resonance being possible if Saturn's equinox is
librating relative to the node of the $f_8$ eigenmode. We present analytical
estimates of the dependence of the resonant argument on the orbital elements of
Iapetus. We find that this Iapetus-$g_5$ secular resonance could have been
established only after the passage of Iapetus through the 5:1 mean-motion
resonance with Titan, possibly in the last Gyr. Using numerical simulations, we
show that the capture into the secular resonance appears to be a
low-probability event. While the Iapetus-$g_5$ secular resonance can
potentially help us put new constraints on the past dynamics of the Saturnian
system, uncertainties in both the spin axis dynamics of Saturn and the tidal
evolution rate of Titan make it impossible to make any firm conclusions about
the resonance's longevity and origin.",1809.09072v1
2015-04-23,Universal spin-momentum locking of evanescent waves,"We show the existence of an inherent property of evanescent electromagnetic
waves: spin-momentum locking, where the direction of momentum fundamentally
locks the polarization of the wave. We trace the ultimate origin of this
phenomenon to complex dispersion and causality requirements on evanescent
waves. We demonstrate that every case of evanescent waves in total internal
reflection, surface states and optical fibers/waveguides possesses this
intrinsic spin-momentum locking. We also introduce a universal right-handed
triplet consisting of momentum, decay and spin for evanescent waves. We derive
the Stokes parameters for evanescent waves which reveal an intriguing result -
every fast decaying evanescent wave is inherently circularly polarized with its
handedness tied to the direction of propagation. We also show the existence of
a fundamental angle associated with total internal reflection (TIR) such that
propagating waves locally inherit perfect circular polarized characteristics
from the evanescent wave. This circular TIR condition occurs if and only if the
ratio of permittivities of the two dielectric media exceeds the golden ratio.
Our work leads to a unified understanding of this spin-momentum locking in
various nanophotonic experiments and sheds light on the electromagnetic analogy
with the quantum spin hall state for electrons.",1504.06361v2
1996-05-23,Optical conductivity of strongly correlated electron systems,"We present an exact diagonalization study of the frequency and wave vector
dependent conductivity $\sigma(q,\omega)$ in small clusters of $2D$ $t$$-$$J$
model. Unlike the related dynamical density correlation function,
$\sigma(q=0,\omega)$ in the underdoped regime has the exchange constant $J$ as
its characteristic energy scale and is dominated by a resonance-like excitation
with frequency $\sim 1.7J$. We interpret this as transition to a $p$-like
excited state of a spin-bag type quasiparticle (or, alternatively, a tightly
bound spinon-holon pair) and show that a simple calculation based on the string
picture explains the numerical results semiquantitatively. For doping levels
$\ge 25% t$ remains the only energy scale of $\sigma(q=0,\omega)$.",9605151v2
2000-10-05,Screening Breakdown on the Route toward the Metal-Insulator Transition in Modulation Doped Si/SiGe Quantum Wells,"Exploiting the spin resonance of two-dimensional (2D) electrons in SiGe/Si
quantum wells we determine the carrier-density-dependence of the magnetic
susceptibility. Assuming weak interaction we evaluate the density of states at
the Fermi level D(E_F), and the screening wave vector, q_TF. Both are constant
at higher carrier densities n, as for an ideal 2D carrier gas. For n < 3e11
cm-2, they decrease and extrapolate to zero at n = 7e10 cm-2. Calculating the
mobility from q_TF yields good agreement with experimental values justifying
the approach. The decrease in D(E_F) is explained by potential fluctuations
which lead to tail states that make screening less efficient and - in a
positive feedback - cause an increase of the potential fluctuations. Even in
our high mobility samples the fluctuations exceed the electron-electron
interaction leading to the formation of puddles of mobile carriers with at
least 1 micrometer diameter.",0010077v1
2000-12-28,Exotic Superconducting Phase in CeCu2Si2 Close to Antiferromagnetism : A Cu-NQR Study under Hydrostatic Pressure,"We report Cu nuclear-quadrupole-resonance results under pressure on a
homogeneous CeCu2Si2 (Tc = 0.65 K) that revealed critical magnetic fluctuations
at the border to an antiferromagnetic phase. This exotic superconducting phase
evolves into the typical heavy-fermion superconducting phase at minute
pressures exceeding Pc ~ 0.2 GPa. The nuclear spin-lattice relaxation data in a
pressure range 0.85 - 2.58 GPa are shown to be accountable by the SCR theory
based on the nearly antiferromagnetic Fermi-liquid model. In 0 < P < Pc ~ 0.2
GPa, by contrast, we conclude that the exotic superconducting phase manifests
itself under the unconventional normal state where antiferromagnetic waves
propagate over a long range without any trace of antiferromagnetic order and
thereby the heavy-fermion state breaks up.",0012493v1
2001-11-10,Detailed Structure of the Magnetic Excitation Spectra of YBa2Cu3Oy and Its Implication on the Physical Characteristics of the Electron System,"Detailed structure of the magnetic excitation spectra x""(q,w) of the
superconducting oxide YBa2Cu3O6.5(the transition temperature Tc ~ 52 K) in the
wave vector (q)- and the energy(w)-space, and its temperature (T) dependence
have been studied. By adopting an effective energy dispersion of the quasi
particles which can reproduce the shape of the Fermi surface and by introducing
the exchange interaction between the Cu spins, a rather satisfactory agreement
between the calculation and the experimentally observed data can be obtained.
In the study, it has been found that the effects of the quasi particle- energy
broadening on the excitation spectra x""(q,w) is important. The sharp resonance
peak observed at w ~ 40 meV for the optimally doped system of YBa2Cu3Oy can be
naturally reproduced by the present model",0111190v3
2001-11-28,Network patterns and strength of orbital currents in layered cuprates,"In a frame of the $t-J-G$ model we derive the microscopical expression for
the circulating orbital currents in layered cuprates using the anomalous
correlation functions. In agreement with $\mu$-on spin relaxation ($\mu$SR),
nuclear quadrupolar resonance (NQR) and inelastic neutron scattering(INS)
experiments in YBa$_2$Cu$_3$O$_{6+x}$ we successfully explain the order of
magnitude and the monotonous increase of the {\it internal} magnetic fields
resulting from these currents upon cooling. However, the jump in the intensity
of the magnetic fields at T$_c$ reported recently seems to indicate a
non-mean-field feature in the coexistence of current and superconducting states
and the deviation of the extended charge density wave vector instability from
its commensurate value {\bf Q}$\approx(\pi,\pi$) in accordance with the
reported topology of the Fermi surface.",0111528v1
2003-10-30,Entanglement interferometry for precision measurement of atomic scattering properties,"We report on a two-particle matter wave interferometer realized with pairs of
trapped 87Rb atoms. Each pair of atoms is confined at a single site of an
optical lattice potential. The interferometer is realized by first creating a
coherent spin-mixture of the two atoms and then tuning the inter-state
scattering length via a Feshbach resonance. The selective change of the
inter-state scattering length leads to an entanglement dynamics of the
two-particle state that can be detected in a Ramsey interference experiment.
This entanglement dynamics is employed for a precision measurement of atomic
interaction parameters. Furthermore, the interferometer allows to separate
lattice sites with one or two atoms in a non-destructive way.",0310719v1
2004-02-26,Unifying Magnons and Triplons in Stripe-Ordered Cuprate Superconductors,"Based on a two-dimensional model of coupled two-leg spin ladders, we derive a
unified picture of recent neutron scattering data of stripe-ordered
La_(15/8)Ba_(1/8)CuO_4, namely of the low-energy magnons around the
superstructure satellites and of the triplon excitations at higher energies.
The resonance peak at the antiferromagnetic wave vector Q_AF in the
stripe-ordered phase corresponds to a saddle point in the dispersion of the
magnetic excitations. Quantitative agreement with the neutron data is obtained
for J= 130-160 meV and J_cyc/J = 0.2-0.25.",0402659v2
2004-09-30,Fermion-mediated BCS-BEC Crossover in Ultracold Potassium-40 Gases,"Studies of Feshbach resonance phenomena in fermionic alkali gases have drawn
heavily on the intuition afforded by a Fermi-Bose theory which presents the
Feshbach molecule as a featureless Bose particle. While this model may provide
a suitable platform to explore the lithium-6 system, we argue that its
application to potassium-40, where the hyperfine structure is inverted, is
inappropriate. Introducing a three-state Fermi model, where a spin state is
shared by the open and closed channel states, we show that effects of ``Pauli
blocking'' are recorded in the internal structure of the condensate wave
function.",0409756v2
2005-04-22,Perturbation of magnetostatic modes observed by FMRFM,"Magnetostatic modes of Yttrium Iron Garnet (YIG) films are investigated by
ferromagnetic resonance force microscopy (FMRFM). A thin film ``probe'' magnet
at the tip of a compliant cantilever introduces a local inhomogeneity in the
internal field of the YIG sample. This influences the shape of the sample's
magnetostatic modes, thereby measurably perturbing the strength of the force
coupled to the cantilever. We present a theoretical model that explains these
observations; it shows that tip-induced variation of the internal field creates
either a local ``potential barrier'' or ``potential well'' for the
magnetostatic waves. The data and model together indicate that local magnetic
imaging of ferromagnets is possible, even in the presence of long-range spin
coupling, through the induction of localized magnetostatic modes predicted to
arise from sufficiently strong tip fields.",0504598v1
2005-11-07,Density-functional theory of strongly correlated Fermi gases in elongated harmonic traps,"Two-component Fermi gases with tunable repulsive or attractive interactions
inside quasi-one-dimensional (Q1D) harmonic wells may soon become the cleanest
laboratory realizations of strongly correlated Luttiger and Luther-Emery
liquids under confinement. We present a microscopic Kohn-Sham
density-functional theory of these systems, with specific attention to a gas on
the approach to a confinement-induced Feshbach resonance. The theory employs
the one-dimensional Gaudin-Yang model as the reference system and transfers the
appropriate Q1D ground-state correlations to the confined inhomogeneous gas
{\it via} a suitable local-density approximation to the exchange and
correlation energy functional. Quantitative understanding of the role of the
interactions in the bulk shell structure of the axial density profile is
thereby achieved. While repulsive intercomponent interactions depress the
amplitude of the shell structure of the noninteracting gas, attractive
interactions stabilize atomic-density waves through spin pairing. These should
be clearly observable in atomic clouds containing of the order of up to a
hundred atoms.",0511158v1
2005-11-08,Solitons of Bose-Fermi mixtures in a strongly elongated trap,"It is shown that a Bose-Fermi mixture of a degenerate gas of spin-polarized
fermions, whose number significantly exceeds the number of bosons, embedded in
a strongly anisotropic trap, is described by the one-dimensional coupled
nonlinear Schrodinger equation for the boson component and the wave equation
with external source for the fermion component. Depending on the type of
boson-fermion interaction, the system may display modulational instability and
the existence of solitons in the fermion and boson components respectively.
Such solitons represent either a local decrease (increase) of the density of
both the components or a decrease of the density in one component and an
increase of the density in the other component. It is shown that the type of
the effective interactions can be easily managed by varying the trap geometry
or by means of Feshbach resonance.",0511206v2
2006-09-13,Hidden order in 1D Bose insulators,"We investigate the phase diagram of spinless bosons with long range (~ 1/r^3)
repulsive interactions, relevant to ultracold polarized atoms or molecules,
using DMRG. Between the two conventional insulating phases, the Mott and
density wave phases, we find a new phase possessing hidden order revealed by
non local string correlations analogous to those characterizing the Haldane
gapped phase of integer spin chains. We develop a mean field theory that
describes the low energy excitations in all three insulating phases. This is
used to calculate the absorption spectrum due to oscillatory lattice
modulation. We predict a sharp resonance in the spectrum due to a collective
excitation of the new phase that would provide clear evidence for the existence
of this phase.",0609307v2
2006-07-19,Light Quark Resonances in pbar p Annihilations at 5.2 GeV/c,"Data from the Fermilab E835 experiment have been used to study the reaction
pbar p -> eta eta pi0 at 5.2 GeV/c. A sample of 22 million six photons events
has been analyzed to construct the Dalitz plot containing ~80k eta eta pi0
events. A partial wave analysis of the data has been done. Six f_J-states
decaying into eta eta and five a_J-states decaying into eta pi0 are identified
in the mass region ~1.3 and 2.4 GeV, and their masses, widths and spins are
determined by maximum likelihood analysis of the data. Two f_0 states are
identified with the popular candidates for the lightest scalar glueball,
f_0(1500) and f_0(1710).",0607034v1
2001-11-06,Coherent Pair State of Pion in Constituent Quark Model,"A coherent state of pions is introduced to the nonrelativistic quark model.
The coherent pair approximation is employed for the pion field in order to
maintain the spin-isospin symmetry. In this approximation the pion is localized
in the momentum space, and the vertex form factor in the pion-quark interaction
is derived from this localization. The nucleon masses and wave functions are
calculated using this model, and our results are compared to those of the quark
model with the one pion exchange potential. Similar result is obtained for the
mass spectrum, but there exists a clear difference in the internal structure of
nucleon resonances.",0111050v2
2004-06-14,Influence of tensor interactions on masses and decay widths of dibaryons,"The influence of gluon and Goldstone boson induced tensor interactions on the
dibaryon masses and D-wave decay widths has been studied in the quark
delocalization, color screening model. The effective S-D wave transition
interactions induced by gluon and Goldstone boson exchanges decrease rapidly
with increasing strangeness of the channel. The tensor contribution of K and
$\eta$ mesons is negligible in this model. There is no six-quark state in the
light flavor world studied so far that can become bound by means of these
tensor interactions besides the deuteron. The partial D-wave decay widths of
the $IJ^p={1/2}2^+$ N$\Omega$ state to spin 0 and 1 $\Lambda\Xi$ final states
are 12.0 keV and 21.9 keV respectively. This is a very narrow dibaryon
resonance that might be detectable in relativistic heavy ion reactions by
existing RHIC detectors through the reconstruction of the vertex mass of the
decay product $\Lambda\Xi$ and by the COMPAS detector at CERN or at JHF in
Japan and the FAIR project in Germany in the future.",0406145v1
2003-01-27,The Hypercentral Constituent Quark Model,"The hypercentral constituent quark model contains a spin independent
three-quark interaction inspired by lattice QCD calculations which reproduces
the average energy of SU(6) multiplets. The splittings are obtained with a
residual generalized SU(6)-breaking interaction including an isospin dependent
term. The long standing problem of the Roper is absent and all the 3- and
4-star states are well reproduced. The model has been used in a systematic way
for transverse and longitudinal electromagnetic transition form factor of the
3- and 4- star and also for the missing resonances. The prediction of the
electromagnetic helicity amplitudes agrees quite well with the data except for
low $Q^2$, showing that it can supply a realistic set of quark wave functions.
In particular we report the calculated helicity amplitude $A_{1/2}$ for the
$S11(1535)$, which is in agreement with the TJNAF data.",0301081v1
2005-07-26,Variational Monte Carlo study of pentaquark states,"Accurate numerical solution of the five-body Schrodinger equation is effected
via variational Monte Carlo. The spectrum is assumed to exhibit a narrow
resonance with strangeness S=+1. A fully antisymmetrized and pair-correlated
five-quark wave function is obtained for the assumed non-relativistic
Hamiltonian which has spin, isospin, and color dependent pair interactions and
many-body confining terms which are fixed by the non-exotic spectra. Gauge
field dynamics are modeled via flux tube exchange factors. The energy
determined for the ground states with J=1/2 and negative (positive) parity is
2.22 GeV (2.50 GeV). A lower energy negative parity state is consistent with
recent lattice results. The short-range structure of the state is analyzed via
its diquark content.",0507061v2
2005-12-21,N phi state in chiral quark model,"The structures of N phi states with spin-parity J^{p}=3/2^- and J^p=1/2^- are
dynamically studied in both the chiral SU(3) quark model and the extended
chiral SU(3) quark model by solving a resonating group method (RGM) equation.
The model parameters are taken from our previous work, which gave a
satisfactory description of the energies of the baryon ground states, the
binding energy of the deuteron, the nucleon-nucleon (NN) scattering phase
shifts, and the hyperon-nucleon (YN) cross sections. The channel coupling of N
phi and Lambda K* is considered, and the effect of the tensor force which
results in the mixing of S and D waves is also investigated. The results show
that the N phi state has an attractive interaction, and in the extended chiral
SU(3) quark model such an attraction plus the channel coupling effect can
consequently make for an N phi quasi-bound state with several MeV binding
energy.",0512079v1
2004-05-03,Physical Properties of Sulfur Near the Polymerization Transition,"Acoustical measurements, electron spin resonance, and Raman spectroscopy have
been employed to probe sulfur over the temperature range 80 to 180 C, which
includes the polymerization transition and the supercooled liquid state.
Acoustical properties (sound velocity, absorption and impedance) have been
studied with both longitudinal and transverse waves at frequencies between 500
kHz and 22 MHz. The results confirm that polymeric sulfur is a solution of long
chain molecules in monomeric solvent, and that the polymerization transition is
not a second order phase transition, as was proposed theoretically. Sulfur is a
viscous liquid, but not viscoelastic, both below and above the polymerization
transition temperature. It is shown that the classical Navier-Stokes theory is
not applicable to the sound absorption in liquid sulfur in the highly viscous
state.",0405012v1
2006-10-30,Coupled cavity QED for coherent control of photon transmission (I): Green function approach for hybrid systems with two-level doping,"This is the first one of a series of our papers theoretically studying the
coherent control of photon transmission along the coupled resonator optical
waveguide (CROW) by doping artificial atoms for various hybrid structures. We
will provide the several approaches correspondingly based on Green function,
the mean field method and spin wave theory et al. In the present paper we adopt
the two-time Green function approach to study the coherent transmission photon
in a CROW with homogeneous couplings, each cavity of which is doped by a
two-level artificial atom. We calculate the two-time correlation function for
photon in the weak-coupling case. Its poles predict the exact dispersion
relation, which results in the group velocity coherently controlled by the
collective excitation of the doping atoms. We emphasize the role of the
population inversion of doping atoms induced by some polarization mechanism.",0610250v2
2007-12-20,Density of state and non-magnetic impurity effects in electron-doped cuprates,"We analyze the density of state (DOS) and a non-magnetic impurity effect in
electron-doped cuprates starting from two different scenarios: the
$d_{x^{2}-y^{2}}$-wave superconductivity coexisting with antiferromagnetic spin
density wave (SDW) order versus $d_{x^{2}-y^{2}}$-wave superconductivity with a
higher harmonic. We find that in both cases the local density of state (LDOS)
exhibits two impurity-induced resonance states at low energies. We also find
that for the intermediate value of the SDW gap, the DOS looks similar to that
obtained from the scenario of the $d_{x^{2}-y^{2}}$-wave gap with a higher
harmonic, suggesting the presence of a non-monotonic $d_{x^{2}-y^{2}}$-wave
gap. However, if the SDW gap is sufficiently large the DOS looks more
conventional s-wave like. This obvious difference from the DOS resulted from
the $d_{x^{2}-y^{2}}$-wave gap with a higher harmonic model, could
differentiate the two above scenarios and is needed to be proved in the further
doping dependence of tunneling spectrum measurement.",0712.3307v4
2008-03-06,Improved Study of the Antiprotonic Helium Hyperfine Structure,"We report the initial results from a systematic study of the hyperfine (HF)
structure of antiprotonic helium (n,l) = (37,~35) carried out at the Antiproton
Decelerator (AD) at CERN. We performed a laser-microwave-laser resonance
spectroscopy using a continuous wave (cw) pulse-amplified laser system and
microwave cavity to measure the HF transition frequencies. Improvements in the
spectral linewidth and stability of our laser system have increased the
precision of these measurements by a factor of five and reduced the line width
by a factor of three compared to our previous results. A comparison of the
experimentally measured transition frequencies with three body QED calculations
can be used to determine the antiproton spin magnetic moment, leading towards a
test of CPT invariance.",0803.0876v2
2008-07-01,Probing the isoscalar excitations of 12C with inelastic alpha scattering,"The robust (spin and isospin zero) $\alpha$-particle remains one of the best
projectiles to probe the nuclear isoscalar excitations. In the present work, a
microscopic folding model analysis of the \ac inelastic scattering to the 2$^+$
(4.44 MeV), 0$^+$ (7.65 MeV), 3$^-$ (9.64 MeV), 0$^+$ (10.3 MeV) and 1$^-$
(10.84 MeV) states in $^{12}$C has been performed using the 3-$\alpha$
resonating group method wave functions. The isoscalar transition strengths of
these states were carefully studied based on the coupled-channel analysis using
the microscopic folded form factors. A correlation between the weak binding
and/or short lifetime of the excited state and absorption in the exit channel
of inelastic scattering has been established.",0807.0049v1
2008-07-26,"Instanton sector of correlated electron systems as the origin of populated pseudo-gap and flat ""band"" behavior: analytic solution","Finite temperature instantons between meta-stable vacua of correlated
electronic system are solved analytically for quasi one-dimensional Hubbard
model. The instantons produce dynamic symmetry breaking and connect metallic
state with the dual vacua: superconducting (SC) and spin-density wave (SDW)
states. The instantons spread along the Matsubara's imaginary time and possess
the structure similar to the coordinate-space solitonic lattices previously
discovered in quasi one-dimensional Peierls model. On the microscopic level the
inter-vacua excursion is described by mutual transformations between the
""resonating quartets"" of the couples of electron-hole and Cooper pairs.
Spectral properties of the electrons in the ""instantonic crystal"" reveal
pseudo-gap (PG) behavior, with finite fermionic density of states in the center
of the PG and ``flat-band'' outside of it. Analytically derived inverse
temperature scaling of the pseudo-gap and the densities of the SC and SDW
condensates is discussed in the context of ARPES and STM data in high-Tc
cuprates.",0807.4222v1
2008-08-08,Understanding adsorption of hydrogen atoms on graphene,"Adsorption of hydrogen atoms on a single graphite sheet (graphene) has been
investigated by first-principles electronic structure means, employing
plane-wave based, periodic density functional theory. A reasonably large 5x5
surface unit cell has been employed to study single and multiple adsorption of
H atoms. Binding and barrier energies for sequential sticking have been
computed for a number of configurations involving adsorption on top of carbon
atoms. We find that binding energies per atom range from ~0.8 eV to ~1.9 eV,
with barriers to sticking in the range 0.0-0.2 eV. In addition, depending on
the number and location of adsorbed hydrogen atoms, we find that magnetic
structures may form in which spin density localizes on a
$\sqrt{3}{x}\sqrt{3}{R}30^{\circ}$ sublattice, and that binding (barrier)
energies for sequential adsorption increase (decrease) linearly with the
site-integrated magnetization. These results can be rationalized with the help
of the valence-bond resonance theory of planar $\pi$ conjugated systems, and
suggest that preferential sticking due to barrierless adsorption is limited to
formation of hydrogen pairs.",0808.1312v1
2008-09-27,Photoproduction of spin and charge carriers in halogen-bridged binuclear platinum chain complexes,"Nonlinear lattice relaxation of photoexcited diplatinum-halide chain
compounds is theoretically investigated within a one-dimensional extended
Peierls-Hubbard model. We first illuminate the whole relaxation scenario in
terms of variational wave functions and then visualize each relaxation channel
numerically integrating the Schr\""odinger equation. High-energy excitations
above the electron-hole continuum tend to relax into polarons, while excitons
pumped within the optical gap, unless luminescent, turn into solitonic states
nonradiatively. Neutral and charged solitons coexist as stable photoproducts,
which has never been observed in conventional platinum-halide chains, and they
are highly resonant on the occasion of their birth and geminate recombination.",0809.4760v1
2008-10-01,Warped and eccentric discs around black holes,"Accretion discs around black holes in X-ray binary stars are warped if the
spin axis of the black hole is not perpendicular to the binary orbital plane.
They can also become eccentric through an instability involving a resonance
with the binary orbit. Depending on the thickness of the disc and the
efficiency of dissipative processes, these global deformations may be able to
propagate into the innermost part of the disc in the form of stationary bending
or density waves. We describe the solutions in the linear regime and discuss
the conditions under which a warp or eccentricity is likely to produce
significant activity in the inner region, which may include the excitation of
quasi-periodic oscillations.",0810.0119v1
2008-10-23,Quantum Optomechanics with Single Atom,"The recently increasing explorations for cavity optomechanical coupling
assisted by a single atom or an atomic ensemble have opened an experimentally
accessible fashion to interface quantum optics and nano (micro) -mechanical
systems. In this paper, we study in details such composite quantum dynamics of
photon, phonon and atoms, specified by the triple coupling, which only exists
in this triple hybrid system: The cavity QED system with a movable end mirror.
We exactly diagonalize the Hamiltonian of the triple hybrid system under the
parametric resonance condition. We find that, with the rotating-wave
approximation, the hybrid system is modeled by a generalized spin-orbit
coupling where the orbital angular momentum operator is defined through a
Jordan-Schwinger realization with two bosonic modes, corresponding to the
mirror oscillation and the single mode photon of the cavity. In the
quasi-classical limit of very large angular momentum, this system will behave
like a standard cavity-QED system described by the Jaynes-Cummings model as the
angular momentum operators are transformed to bosonic operators of a single
mode. We test this observation with an experimentally accessible system with
the atom in the cavity with a moving mirror.",0810.4206v1
2009-05-30,THz-range free-electron laser ESR spectroscopy: techniques and applications in high magnetic fields,"The successful use of picosecond-pulse free-electron-laser (FEL) radiation
for the continuous-wave THz-range electron spin resonance (ESR) spectroscopy
has been demonstrated. The combination of two linac-based FELs (covering the
wavelength range of 4 - 250 $\mu$m) with pulsed magnetic fields up to 70 T
allows for multi-frequency ESR spectroscopy in a frequency range of 1.2 - 75
THz with a spectral resolution better than 1%. The performance of the
spectrometer is illustrated with ESR spectra obtained in the
2,2-diphenyl-1-picrylhydrazyl (DPPH) and the low-dimensional organic material
(C$_6$H$_9$N$_2$)CuCl$_3$.",0906.0105v1
2009-06-19,Homogeneous vs. inhomogeneous coexistence of magnetic order and superconductivity probed by NMR in Co and K doped iron pnictides,"In Ba(Fe0.95Co0.05)2As2 all of the 75As NMR intensity at the paramagnetic
resonance position vanishes abruptly below Tonset(SDW)=56 K, indicating that
magnetic (spin density wave) order is present in all of the sample volume,
despite bulk superconductivity below Tc=15 K. The two phases thus coexist
homogeneously at the microscopic scale. In Ba0.6K0.4Fe2As2, on the other hand,
the signal loss below Tonset(SDW)~75 K is not complete, revealing that magnetic
order is bound to finite-size areas of the sample, while the remaining NMR
signal shows a clear superconducting response below Tc=37 K. Thus, the two
phases are not homogeneously mixed, at least for this potassium concentration.
For both samples, spatial electronic and/or magnetic inhomogeneity is shown to
characterize the NMR properties in the normal state.",0906.3708v1
2009-06-25,Possible Multiple Gap Superconductivity with Line Nodes in Heavily Hole-Doped Superconductor KFe2As2 Studied by 75As-NQR and Specific Heat,"We report the 75As nuclear quadrupole resonance (NQR) and specific heat
measurements of the heavily hole-doped superconductor KFe2As2 (Tc = 3.5 K). The
spin-lattice relaxation rate 1/T1 in the superconducting state exhibits quite
gradual temperature dependence with no coherence peak below Tc. The
quasi-particle specific heat C_QP/T shows small specific heat jump which is
about 30% of electronic specific heat coefficient just below Tc. In addition,
it suggests the existence of low-energy quasi-particle excitation at the lowest
measurement temperature T = 0.4 K \simeq Tc/10. These temperature dependence of
1/T1 and C_QP/T can be explained by multiple nodal superconducting gap scenario
rather than multiple fully-gapped s_\pm-wave one within simple gap analysis.",0906.4644v1
2009-12-10,Extending MCAS to hypernuclei and radiative-capture reactions,"Using a Multi-Channel Algebraic Scattering (MCAS) approach we have analyzed
the spectra of two hyper-nuclear systems, Lambda9Be and Lambda13C. We have
studied the splitting of the two odd-parity excited levels (1/2- and 3/2-) at
11 MeV excitation in Lambda13C, originated by the weak Lambda-nucleus
spin-orbit force. We have also considered the splittings of the 3/2+ and 5/2+
levels in both Lambda9Be and Lambda13C, finding how they originate from
couplings to the collective 2+ states of the core nuclei. In both hyper-nuclei,
we suggest that there could be additional low-lying resonant states in the
Lambda-nucleus continua. From the MCAS approach one can extract also the full
coupled-channel scattering wave-function to be used in the calculation of
various transition matrix elements. As a first application, we have considered
the EM-transition matrix elements for the capture reaction Alpha + 3He -> 7Be +
Gamma .",0912.2060v1
2010-02-18,"$^{77}$Se and $^{63}$Cu NMR studies of the electronic correlations in Cu$_x$TiSe$_2$ ($x=0.05, 0.07$)","We report $^{77}$Se and $^{63}$Cu nuclear magnetic resonance (NMR)
investigation on the charge-density-wave (CDW) superconductor Cu$_x$TiSe$_2$
($x=0.05$ and 0.07). At high magnetic fields where superconductivity is
suppressed, the temperature dependence of $^{77}$Se and $^{63}$Cu spin-lattice
relaxation rates 1/T_{1}$ follow a linear relation. The slope of $^{77}1/T_{1}$
vs \emph{T} increases with the Cu doping. This can be described by a modified
Korringa relation which suggests the significance of electronic correlations
and the Se 4\emph{p}- and Ti 3\emph{d}-band contribution to the density of
states at the Fermi level in the studied compounds.",1002.3553v2
2010-03-12,Radiofrequency spectroscopy of $^6$Li p-wave molecules: towards photoemission spectroscopy of a p-wave superfluid,"Understanding superfluidity with higher order partial waves is crucial for
the understanding of high-$T_c$ superconductivity. For the realization of a
superfluid with anisotropic order parameter, spin-polarized fermionic lithium
atoms with strong p-wave interaction are the most promising candidates to date.
We apply rf-spectroscopy techniques that do not suffer from severe final-state
effects \cite{Perali08} with the goal to perform photoemission spectroscopy on
a strongly interacting p-wave Fermi gas similar to that recently applied for
s-wave interactions \cite{Stewart08}. Radiofrequency spectra of both quasibound
p-wave molecules and free atoms in the vicinity of the p-wave Feshbach
resonance located at 159.15\,G \cite{Schunck05} are presented. The observed
relative tunings of the molecular and atomic signals in the spectra with
magnetic field confirm earlier measurements realized with direct rf-association
\cite{Fuchs08}. Furthermore, evidence of bound molecule production using
adiabatic ramps is shown. A scheme to observe anisotropic superfluid gaps, the
most direct proof of p-wave superfluidity, with 1d-optical lattices is
proposed.",1003.2516v1
2010-07-28,Universal Phase Diagram and Reentrant Superconductivity of $Bi$layer Hydrated Na$_x$CoO$_2\cdot y$H$_2$O,"We report duration dependence of superconductivity in a 43 \% humidity
atmosphere and $^{59}$Co nuclear quadrupole resonance (NQR) of polycrystalline
samples of $bi$layer hydrated Na$_x$CoO$_2 \cdot y$H$_2$O. We found a reentrant
behavior of superconductivity with respect to the time duration. We obtained
the universal phase diagram where two superconducting phases and an in-between
magnetic phase are classified by $^{59}$Co NQR frequency. Zero field $^{59}$Co
nuclear spin-lattice relaxation rates $1/T_1$ indicated a magnetic critical
slowing down at 5 K in the magnetic phase, excluding a charge density wave
ordering, and an enhancement at and just above $T_\mathrm{c}$ in a new
superconducting phase, suggesting a coexistence of magnetic ordering.",1007.4873v1
2011-01-26,d-wave pairing from spin fluctuations in the KxFe{2-y}Se2 superconductors,"Angle-resolved photoemission spectroscopy measurements on the recently
discovered superconduc- tors in the KFe2Se2 family with critical temperatures
up to - 33K suggest that no Fermi pockets of hole character centered on the
{\Gamma} point of the Brillouin zone are present, in contrast to all other
known ferropnictide and ferrochalcogenide superconductors. Using a fluctuation
exchange approximation and a 5-orbital tight-binding description of the band
structure, we calculate the effective pairing interaction. We find that the
pairing state in this system is most likely to have d-wave symmetry due to pair
scattering between the remaining electron Fermi pockets at wave vector q -
({\pi}, {\pi}), but without any symmetry-imposed nodes for the given Fermi
surface. We propose experimental tests of this result, including the form of
the resonance spectrum probed by inelastic neutron scattering.",1101.4988v1
2011-02-01,One-dimentional magnonic crystal as a medium with magnetically tunable disorder on a periodical lattice,"We show that periodic magnetic nanostructures (magnonic crystals) represent
an ideal system for studying excitations on disordered periodical lattices
because of the possibility of controlled variation of the degree of disorder by
varying the applied magnetic field. Ferromagnetic resonance (FMR) data
collected inside minor hysteresis loops for a periodic array of Permalloy
nanowires of alternating width and magnetic force microscopy images of the
array taken after running each of these loops were used to establish convincing
evidence that there is a strong correlation between the type of FMR response
and the degree of disorder of the magnetic ground state. We found two types of
dynamic responses: anti-ferromagnetic (AFM) and ferromagnetic (FM), which
represent collective spin wave modes or collective magnonic states. Depending
on the history of sample magnetization either AFM or FM state is either the
fundamental FMR mode or represents a state of a magnetic defect on the
artificial crystal. A fundamental state can be transformed into a defect one
and vice versa by controlled magnetization of the sample.",1102.0069v1
2011-08-15,Helicity Asymmetry in gamma p -> pi+ n with FROST,"The main objective of the FROST experiment at Jefferson Lab is the study of
baryon resonances. The polarization observable E for the reaction gamma p to
pi+n has been measured as part of this program. A circularly polarized tagged
photon beam with energies from 0.35 to 2.35 GeV was incident on a
longitudinally polarized frozen-spin butanol target. The final-state pions were
detected with the CEBAF Large Acceptance Spectrometer. Preliminary polarization
data agree fairly well with present SAID and MAID partial-wave analyses at low
photon energies. In most of the covered energy range, however, significant
deviations are observed. These discrepancies underline the crucial importance
of polarization observables to further constrain these analyses.",1108.3050v1
2011-09-08,Diffractive Dissociation into π- π- π+ Final States at COMPASS,"Diffractive dissociation reactions studied at the COMPASS experiment at CERN
provide access to the light-meson spectrum. During a pilot run in 2004, using a
pion beam and a lead target, 420k \pi- \pi- \pi+ final-state events with masses
below 2.5 GeV/c2 were recorded, yielding a significant spin-exotic signal for
the controversial \pi 1(1600) resonance. After a significant upgrade of the
spectrometer in 2007, the following two years were dedicated to meson
spectroscopy. Using again a pion beam, but now with a liquid hydrogen target,
an unique statistics of ~60M events of the same final state was gathered in
2008. During a short campaign in 2009, the H2 target was exchanged by several
solid state targets in order to compare final states produced on targets with
different atomic numbers. A partial-wave Analysis (PWA) was performed on all
these data sets and results are presented.",1109.1789v2
2011-11-08,Analysis of the Collective Behavior of a 10 by 10 Array of Fe3O4 Dots in a Large Micromagnetic Simulation,"We report a full (3D) micromagnetic simulation of a set of 100 ferrite
(Fe$_3$O$_4$) cylindrical dots, arranged in a 10 by 10 square (planar) array of
side 3.27 $\mu$m, excited by an external in-plane magnetic field. The resulting
power spectrum of magnetic excitations and the dynamical magnetization field at
the resulting resonance modes were investigated. The absorption spectrum
deviates considerably from that of a single particle reference simulation,
presenting a mode-shifting and splitting effect. We found an inversion symmetry
through the center of the array, in the sense that each particle and its
inversion counterpart share approximately the same magnetization mode behavior.
Magnonic designs aiming at synchronous or coherent tunings of spin-wave
excitations at given spatially separated points within a regular square array
may benefit from the new effects here described.",1111.1866v1
2011-12-09,Interfacial coupling across a modified interface studied with ferromagnetic resonance,"Using spin waves we directly probe the interface of an exchange biased
Ni$_{80}$Fe$_{20}$/Ir$_{25}$Mn$_{75}$ film which has been modified by the
presence of an Au dusting layer. Combining this experimental data with a
discretised simulation model, parameters relating to interface exchange
coupling and modification of interface magnetisation are determined. Exchange
coupling is found to be relatively uniform as gold thickness is increased, and
undergoes a sudden drop at 1.5$\textrm{\AA}$ of gold. Interface magnetisation
decreases as a function of the gold dusting thickness. Antiparallel alignment
of the ferromagnet and antiferromagnet supress the interface magnetisation
compared to when they are in parallel alignment. These findings imply that the
interface region has specific magnetisation states which depend on the
ferromagnet orientation.",1112.2045v1
2011-12-30,"ESR and TSL study of hole capture in PbWO_4:Mo,La and PbWO_4:Mo,Y scintillator crystals","The processes of hole localization in double-doped PbWO_4:Mo,La and
PbWO_4:Mo,Y single crystals have been studied by continuous wave and pulse
electron spin resonance (ESR) and thermally stimulated luminescence (TSL)
methods. We show that the holes created by the UV irradiation are preferably
trapped at lattice oxygen ions in the vicinity of perturbing defects such as
lead vacancies, impurity ions (La, Y, Mo), and other lattice imperfections.
This leads to a variety of O^- centers, which differ both by thermal stability
(from about 170 K up to 240 K) and ESR parameters. The hole centers of this
type were not observed neither in PbWO_4:Mo nor in PbWO_4:La(Y) crystals. The
recombination processes of thermally released holes with electrons stored at
different traps, including Pb^+ - WO_3 and (MoO_4)^3- centers, are
systematically studied by TSL. Thermal stability parameters are defined by ESR
and TSL techniques for different O^- type defects.",1201.0092v1
2012-04-10,Complex itinerant ferromagnetism in noncentrosymmetric Cr11Ge19,"The noncentrosymmetric ferromagnet Cr11Ge19 has been investigated by
electrical transport, AC and DC magnetization, heat capacity, x-ray
diffraction, resonant ultrasound spectroscopy, and first principles electronic
structure calculations. Complex itinerant ferromagnetism in this material is
indicated by nonlinearity in conventional Arrott plots, unusual behavior of AC
susceptibility, and a weak heat capacity anomaly near the Curie temperature (88
K). The inclusion of spin wave excitations was found to be important in
modeling the low temperature heat capacity. The temperature dependence of the
elastic moduli and lattice constants, including negative thermal expansion
along the c axis at low temperatures, indicate strong magneto-elastic coupling
in this system. Calculations show strong evidence for itinerant ferromagnetism
and suggest a noncollinear ground state may be expected.",1204.2254v2
2012-07-04,"Long-range incommensurate charge fluctuations in (Y,Nd)Ba2Cu3O(6+x)","There are increasing indications that superconductivity competes with other
orders in cuprate superconductors, but obtaining direct evidence with
bulk-sensitive probes is challenging. We have used resonant soft x-ray
scattering to identify two-dimensional charge fluctuations with an
incommensurate periodicity of $\bf \sim 3.2$ lattice units in the copper-oxide
planes of the superconductors (Y,Nd)Ba$_2$Cu$_3$O$_{6+x}$ with hole
concentrations $0.09 \leq p \leq 0.13$ per planar Cu ion. The intensity and
correlation length of the fluctuation signal increase strongly upon cooling
down to the superconducting transition temperature, $T_c$; further cooling
below $T_c$ abruptly reverses the divergence of the charge correlations. In
combination with prior observations of a large gap in the spin excitation
spectrum, these data indicate an incipient charge-density-wave instability that
competes with superconductivity.",1207.0915v1
2012-07-08,Bistable behavior of a two-mode Bose-Einstein condensate in an optical cavity,"We consider a two-component Bose-Einstein condensate in a one-dimensional
optical cavity. Specifically, the condensate atoms are taken to be in two
degenerate modes due to their internal hyperfine spin degrees of freedom and
they are coupled to the cavity field and an external transverse laser field in
a Raman scheme. A parallel laser is also exciting the cavity mode. When the
pump laser is far detuned from its resonance atomic transition frequency, an
effective nonlinear optical model of the cavity-condensate system is developed
under Discrete Mode Approximation (DMA), while matter-field coupling has been
considered beyond the Rotating Wave Approximation. By analytical and numerical
solutions of the nonlinear dynamical equations, we examine the mean cavity
field and population difference (magnetization) of the condensate modes. The
stationary solutions of both the mean cavity field and normalized magnetization
demonstrate bistable behavior under certain conditions for the laser pump
intensity and matter-field coupling strength.",1207.1858v1
2012-08-17,Detection of domain wall eigenfrequency in infinity-shaped magnetic nanostructures,"The dynamics of a magnetic infinity-shaped nanostructure has been
experimentally studied by two different techniques such as the sinusoidal
resonance excitation and the damped short pulse excitation to measure the
eigenfrequency of domain walls. Direct observation of the magnetic domain wall
nucleation has been measured in the frequency domain. Electrical measurements
of the domain wall dynamics in the frequency domain reveal the existence of
multi-eigenmodes for large excitation amplitudes. The time-resolved
measurements show that the frequency of the damped gyration is similar to that
of the frequency domain and coexistence of spin wave excitations.",1208.3527v1
2013-03-24,Self-energy effects in electronic Raman spectra of doped cuprates due to magnetic fluctuations,"We present results for magnetic excitations in doped copper oxides using the
random phase approximation and itinerant electrons. In the [1,0] direction the
observed excitations resemble dispersive quasi-particles both in the normal and
superconducting state similar as in recent resonant inelastic X-ray scattering
(RIXS) experiments. In the [1,1] direction the excitations form, except for the
critical region near the antiferromagnetic wave vector ${\bf Q}=(\pi,\pi)$,
only very broad continua. Using the obtained spin propagators we calculate
electron self-energies and their effects on electronic Raman spectra. We show
that the recently observed additional peak at about twice the pair breaking in
B$_{1g}$ symmetry below T$_c$ in HgBa$_2$CuO$_{4+\delta}$ can be explained as a
self-energy effect where a broken Cooper pair and a magnetic excitation appear
as final states. The absence of this peak in B$_{2g}$ symmetry, which probes
mainly electrons near the nodal direction, is explained by their small
self-energies compared to those in the antinodal direction.",1303.5975v1
2013-05-29,Matter around Kerr black holes in scalar-tensor theories: scalarization and superradiant instability,"In electrovacuum stationary, asymptotically flat black holes in scalar-tensor
theories of gravity are described by the Kerr-Newman family of solutions, just
as in general relativity. We show that there exist two mechanisms which can
render Kerr black holes unstable when matter is present in the vicinity of the
black hole, as this induces an effective mass for the scalar. The first
mechanism is a tachyonic instability that appears when the effective mass
squared is negative, triggering the development of scalar hair --- a black hole
version of ""spontaneous scalarization"". The second instability is associated
with superradiance and is present when the effective mass squared is positive
and when the black hole spin exceeds a certain threshold. The second mechanism
is also responsible for a resonant effect in the superradiant scattering of
scalar waves, with amplification factors as large as 10^5 or more.",1305.6936v2
2013-07-03,Suppression of the S-wave production of (3/2)^+ + (1/2)^- heavy meson pairs in e^+e^- annihilation,"The heavy meson-antimeson pairs, where one is an excited $\bigl ({3 \over 2}
\bigr) ^+ $ meson and the other is a ground state $\bigl ({1 \over 2} \bigr)
^-$ meson, namely the pairs ($D_1(2420) \bar D$ + c.c.), ($D_1(2420) \bar D^*$
+ c.c.), ($D_2(2460) \bar D^*$ + c.c.) in the charm sector and ($B_1(5721) \bar
B$ + c.c.), ($B_1(5721) \bar B^*$ + c.c.), ($B_2(5747) \bar B^*$ + c.c.) in the
bottom sector, are allowed, by the quantum numbers, to be produced in the $S$
wave in $e^+e^-$ annihilation. We show, however, that such $S$-wave production
is forbidden by the heavy quark spin symmetry. Thus the yield of the considered
meson pairs in $e^+e^-$ annihilation should be significantly suppressed near
the respective thresholds. In our view, this substantially weakens the
arguments for considering the Y(4260) charmonium-like resonance as a $D_1 \bar
D$ molecular state.",1307.1072v1
2013-08-16,Comparative study of nuclear effects in polarized electron scattering from 3He,"We present a detailed analysis of nuclear effects in inclusive electron
scattering from polarized 3He nuclei for polarization asymmetries, structure
functions and their moments, both in the nucleon resonance and deep-inelastic
regions. We compare the results of calculations within the weak binding
approximation at finite Q^2 with the effective polarization ansatz often used
in experimental data analyses, and explore the impact of \Delta\ components in
the nuclear wave function and nucleon off-shell corrections on extractions of
the free neutron structure. Using the same framework we also make predictions
for the Q^2 dependence of quasielastic scattering from polarized 3He, data on
which can be used to constrain the spin-dependent nuclear smearing functions in
3He.",1308.3723v1
2013-10-12,Introducing single Mn2+ ions into spontaneously coupled quantum dot pairs,"We present the photoluminescence excitation study of the self-assembled
CdTe/ZnTe quantum dots doped with manganese ions. We demonstrate the
identification method of spontaneously coupled quantum dots pairs containing
single Mn2+ ions. As the result of the coupling, the resonant absorption of the
photon in one quantum dot is followed by the exciton transfer into a
neighboring dot. It is shown that the Mn2+ ion might be present in the
absorbing, emitting or both quantum dots. The magnetic properties of the Mn2+
spin are revealed by a characteristic sixfold splitting of the excitonic line.
The statistics of the value of this splitting is analyzed for the large number
of the dots and gives the information on the maximum density of the neutral
exciton wave function.",1310.3383v1
2014-03-05,Short-period pulsar oscillations following a glitch,"Following a glitch, the crust and magnetized plasma in the outer core of a
neutron star are believed to rapidly establish a state of co-rotation within a
few seconds by process analogous to classical Ekman pumping. However, in ideal
magnetohydrodynamics, a final state of co-rotation is inconsistent with
conservation of energy of the system. We demonstrate that, after the Ekman-like
spin up is completed, magneto-inertial waves continue to propagate throughout
the star, exciting torsional oscillations in the crust and plasma. The crust
oscillation is irregular and quasi-periodic, with a dominant frequency of the
order of seconds. Crust oscillations commence after an Alfv\'en crossing time,
approximately half a minute at the magnetic pole, and are subsequently damped
by the electron viscosity over approximately an hour. In rapidly rotating
stars, the magneto-inertial spectrum in the core approaches a continuum, and
crust oscillations are damped by resonant absorption analogous to
quasi-periodic oscillations in magnetars. The oscillations predicted are
unlikely to be observed in timing data from existing radio telescopes, but may
be visible to next generation telescope arrays.",1403.1046v2
2014-09-03,A common optical algorithm for the evaluation of specular spin polarized neutron and Mössbauer reflectivities,"Using the general approach of Lax for multiple scattering of waves a 2x2
covariant expression for the reflectivity of polarized slow neutrons of a
magnetic layer structure of arbitrary complexity is given including
polarization effects of the external magnetic field. The present formalism is
identical to the earlier published one for the (nuclear) resonant X-ray
(Mossbauer) reflectivity and properly takes the effect of the external magnetic
field of arbitrary direction on the neutron beam into account. The form of the
reflectivity matrix allows for an efficient numerical calculation.",1409.1056v1
2014-11-28,Magnetic field tuning of exciton polaritons in a semiconductor microcavity,"We detail the influence of a magnetic field on exciton-polaritons inside a
semiconductor microcavity. Magnetic field can be used as a tuning parameter for
exciton and photon resonances. We discuss the change of the exciton energy, the
oscillator strength and redistribution of the polariton density along the
dispersion curves due to the magnetically-induced detuning. We have observed
that field-induced shrinkage of the exciton wave function has a direct
influence not only on the exciton oscillator strength, which is observed to
increase with the magnetic field, but also on the polariton linewidth. We
discuss the effect of the Zeeman splitting on polaritons which magnitude
changes with the exciton Hopfield coefficient and can be modelled by
independent coupling of the two spin components of excitons with cavity
photons.",1411.7875v1
2015-02-03,Exploiting the Symmetries of P and S wave for B --> K^* mu^+ mu^-,"After summarizing the current theoretical status of the four-body decay B -->
K^*(--> K pi) mu^+ mu^-, we apply the formalism of spin-symmetries to the full
angular distribution, including the S-wave part involving a broad scalar
resonance K0^*. While we recover in the P-wave sector the known relation
between the angular observables Pi('), we find in the S-wave sector two new
relations connecting the coefficients of the S-wave angular distribution and
reducing the number of independent S-wave observables from six to four.
Included in the experimental data analysis, these relations can help to reduce
the background from S-wave pollution. We further point out the discriminative
power of the maximum of the angular observable P2 as a charm-loop insensitive
probe of right-handed currents. Moreover, we show that in absence of
right-handed currents the angular observables P4' and P5' fulfill the relation
P4' = beta P5' at the position where P2 reaches its maximum.",1502.00920v2
2015-04-17,Perspectives on gravity-induced radiative processes in astrophysics,"Single-vertex Feynman diagrams represent the dominant contribution to
physical processes, but are frequently forbidden kinematically. This is changed
when the particles involved propagate in a gravitational background and acquire
an effective mass. Procedures are introduced that allow the calculation of
lowest order diagrams, their corresponding transition probabilities, emission
powers and spectra to all orders in the metric deviation, for particles of any
spin propagating in gravitational fields described by any metric. Physical
properties of the ""space-time medium"" are also discussed. It is shown in
particular that a small dissipation term in the particle wave equations can
trigger a strong back-reaction that introduces resonances in the radiative
process and affects the resulting gravitational background.",1504.04610v1
2016-04-21,All-in all-out magnetic order and propagating spin-waves in Sm2Ir2O7,"Using resonant magnetic x-ray scattering we address the unresolved nature of
the magnetic groundstate and the low-energy effective Hamiltonian of
Sm$_2$Ir$_2$O$_7$, a prototypical pyrochlore iridate with a finite temperature
metal-insulator transition. Through a combination of elastic and inelastic
measurements, we show that the magnetic ground state is an all-in all-out
(AIAO) antiferromagnet. The magnon dispersion indicates significant electronic
correlations and can be well-described by a minimal Hamiltonian that includes
Heisenberg exchange ($J=27.3(6)$ meV) and Dzyaloshinskii-Moriya interaction
($D=4.9(3)$ meV), which provides a consistent description of the magnetic order
and excitations. In establishing that Sm$_2$Ir$_2$O$_7$ has the requisite
inversion symmetry preserving AIAO magnetic groundstate, our results support
the notion that pyrochlore iridates may host correlated Weyl semimetals.",1604.06401v1
2016-06-24,Two-dimensional electron gas in the regime of strong light-matter coupling: Dynamical conductivity and all-optical measurements of Rashba and Dresselhaus coupling,"A nonperturbative interaction of an electronic system with a laser field can
substantially modify its physical properties. In particular, in two-dimensional
(2D) materials with a lack of inversion symmetry, the achievement of a regime
of strong light-matter coupling allows direct optical tuning of the strength of
the Rashba spin-orbit interaction (SOI). Capitalizing on these results, we
build a theory of the dynamical conductivity of a 2D electron gas with both
Rashba and Dresselhaus SOIs coupled to an off-resonant high-frequency
electromagnetic wave. We argue that strong light-matter coupling modifies
qualitatively the dispersion of the electrons and can be used as a powerful
tool to probe and manipulate the coupling strengths and adjust the frequency
range where optical conductivity is essentially nonzero.",1606.07663v2
2016-07-05,Optical activity of quantum wells,"We report on the observation of optical activity of quantum wells resulting
in the conversion of the light polarization state controlled by the light
propagation direction. The polarization conversion is detected in reflection
measurements. We show that a pure $s$-polarized light incident on a quantum
well is reflected as an elliptically polarized wave. The signal is drastically
enhanced in the vicinity of the light-hole exciton resonance. We show that the
polarization conversion is caused by the spin-orbit splitting of the light hole
states and the birefringence of the studied structure. The bulk inversion
asymmetry constant $\beta_{h} \approx 0.14$ eV\AA, is determined for the ground
light hole subband in a 10 nm ZnSe/ZnMgSSe quantum well.",1607.01226v1
2016-09-03,Deep data mining in a real space: Separation of intertwined electronic responses in a lightly-doped BaFe2As2,"Electronic interactions present in material compositions close to the
superconducting dome play a key role in the manifestation of high-Tc
superconductivity. In many correlated electron systems, however, the parent or
underdoped states exhibit strongly inhomogeneous electronic landscape at the
nanoscale that may be associated with competing, coexisting, or intertwined
chemical disorder, strain, magnetic, and structural order parameters. Here we
demonstrate an approach based on a combination of scanning tunneling
microscopy/spectroscopy (STM/S) and advanced statistical learning for an
automatic separation and extraction of statistically significant electronic
behaviors in the spin density wave (SDW) regime of a lightly (~1%) gold-doped
BaFe2As2. We show that the decomposed STS spectral features have a direct
relevance to fundamental physical properties of the system, such as SDW-induced
gap, pseudogap-like state, and impurity resonance states.",1609.00846v1
2016-10-28,"The microscopic structure of $πNN$, $πNΔ$ and $πΔΔ$ vertices in a hybrid constituent quark model","We present a microscopic description of the strong $\pi NN$, $\pi N\Delta$
and $\pi\Delta\Delta$ vertices. Our starting point is a constituent-quark model
supplemented by an additional $3q\pi$ non-valence component. In the spirit of
chiral constituent-quark models, quarks are allowed to emit and reabsorb a
pion. This multichannel system is treated in a relativistically invariant way
within the framework of point-form quantum mechanics. Starting with a common
$SU(6)$ spin-flavor-symmetric wave function for $N$ and $\Delta$, we calculate
the strength of the $\pi NN$, $\pi N\Delta$ and $\pi\Delta\Delta$ couplings and
the corresponding vertex form factors. Our results are in accordance with
phenomenological fits of these quantities that have been obtained within purely
hadronic multichannel models for baryon resonances.",1610.09242v1
2017-12-05,Exact solution of a two-species quantum dimer model for pseudogap metals,"We present an exact ground state solution of a quantum dimer model introduced
in Ref.[1], which features ordinary bosonic spin-singlet dimers as well as
fermionic dimers that can be viewed as bound states of spinons and holons in a
hole-doped resonating valence bond liquid. Interestingly, this model captures
several essential properties of the metallic pseudogap phase in high-$T_c$
cuprate superconductors. We identify a line in parameter space where the exact
ground state wave functions can be constructed at an arbitrary density of
fermionic dimers. At this exactly solvable line the ground state has a huge
degeneracy, which can be interpreted as a flat band of fermionic excitations.
Perturbing around the exactly solvable line, this degeneracy is lifted and the
ground state is a fractionalized Fermi liquid with a small pocket Fermi surface
in the low doping limit.",1712.01854v2
2018-06-19,Deterministic free-space source of single photons using Rydberg atoms,"We propose an efficient free-space scheme to create single photons in a
well-defined spatiotemporal mode. To that end, we first prepare a single source
atom in an excited Rydberg state. The source atom interacts with a large
ensemble of ground-state atoms via a laser-mediated dipole-dipole exchange
interaction. Using an adiabatic passage with a chirped laser pulse, we produce
a spatially extended spin wave of a single Rydberg excitation in the ensemble,
accompanied by the transition of the source atom to another Rydberg state. The
collective atomic excitation can then be converted to a propagating optical
photon via a coherent coupling field. In contrast to previous approaches, our
single-photon source does not rely on the strong coupling of a single emitter
to a resonant cavity, nor does it require the heralding of collective
excitation or complete Rydberg blockade of multiple excitations in the atomic
ensemble.",1806.07094v3
2018-11-04,Role of gallium diffusion in the formation of a magnetically dead layer at Y3Fe5O12 / Gd3Ga5O12 epitaxial interface,"We have clarified the origin of magnetically dead interface layer formed in
yttrium iron garnet (YIG) films grown at above 700{\deg}C onto gadolinium
gallium garnet (GGG) substrate by means of laser molecular beam epitaxy. The
diffusion-assisted formation of a Ga-rich region at the YIG / GGG interface is
demonstrated by means of composition depth profiling performed by X-ray
photoelectron spectroscopy, secondary ion mass spectroscopy and X-ray and
neutron reflectometry. Our finding is in sharp contrast to the earlier
expressed assumption that Gd acts as a migrant element in the YIG/GGG system.
We further correlate the presence of Ga-rich transition layer with considerable
quenching of ferromagnetic resonance and spin wave propagation in thin YIG
films. Finally, we clarify the origin of the enigmatic low-density overlayer
that is often observed in neutron and X-ray reflectometry studies of the YIG /
GGG epitaxial system.",1811.01321v2
2019-11-03,Hybrid spin-superconducting quantum circuit mediated by deterministically prepared entangled photonic states,"In hybrid quantum systems a controllable coupling can be obtained by
mediating the interactions with dynamically introduced photons. We propose a
hybrid quantum architecture consisting of two nitrogen vacancy center ensembles
coupled to a tunable flux qubit; that are contained on the transmission line of
a multimode nonlinear superconducting coplanar waveguide resonator with an
appended Josephson mixing device. We discuss using entangled propagating
microwaves photons, which through our nonlinear wave-mixing procedure are made
into macroscopically distinct quantum states. We use these states to steer the
system and show that with further amplification we can create a similar
photonic state, which has a more distinct reduction of its uncertainty.
Furthermore, we show that all of this leads to a lengthened coherence time, a
reasonable fidelity which decays to 0.94 and then later increases upward to
stabilize at 0.6 as well as a strengthened entanglement.",1911.00869v1
2014-06-10,Resonantly enhanced kicks from equatorial small mass-ratio inspirals,"We calculate the kick generated by an eccentric black hole binary inspiral as
it evolves through a resonant orbital configuration where the precession of the
system temporarily halts. As a result, the effects of the asymmetric emission
of gravitational waves build up coherently over a large number of orbits. Our
results are calculate using black hole perturbation theory in the limit where
the ratio of the masses of the orbiting objects $\epsilon=m/M$ is small. The
resulting kick velocity scales as $\epsilon^{3/2}$, much faster than the
$\epsilon^2$ scaling of the kick generated by the final merger. For the most
extreme case of a very eccentric ($e\sim 1$) inspiral around a maximally
spinning black hole, we find kicks close to $30,000\;\epsilon^{3/2}$~km/s,
enough to dislodge a black hole from its host cluster or even galaxy. In
reality, such extreme inspirals should be very rare. Nonetheless, the
astrophysical impact of kicks in less extreme inspirals could be
astrophysically significant.",1406.2594v2
2020-08-06,Non-perturbative effects in corrections to quantum master equation arising in Bogolubov-van Hove limit,"We study the perturbative corrections to the {
Gorini-Kossakowski-Sudarshan-Lindblad equation which arises in the weak
coupling limit}. The spin-boson model in the rotating wave approximation at
zero temperature is considered. We show that the perturbative part of the
density matrix satisfies the time-independent
Gorini-Kossakowski-Sudarshan-Lindblad equation for arbitrary order of the
perturbation theory (if all the moments of the reservoir correlation function
are finite). But to reproduce the right asymptotic precision at long times, one
should use { an initial condition different} from the one for exact dynamics.
Moreover, we show that the initial condition for this master equation even
fails to be a density matrix under certain resonance conditions.",2008.02820v6
2016-12-07,Gilbert damping of magnetostatic modes in a yttrium iron garnet sphere,"The magnetostatic mode (MSM) spectrum of a 300$\mu$m diameter single
crystalline sphere of yttrium iron garnet is investigated using broadband
ferromagnetic resonance (FMR). The individual MSMs are identified via their
characteristic dispersion relations and the corresponding mode number tuples
$(nmr)$ are assigned. Taking FMR data over a broad frequency and magnetic field
range allows to analyze both the Gilbert damping parameter~$\alpha$ and the
inhomogeneous line broadening contribution to the total linewidth of the MSMs
separately. The linewidth analysis shows that all MSMs share the same Gilbert
damping parameter $\alpha=2.7(5) \times 10^{-5}$ irrespective of their mode
index. In contrast, the inhomogeneous line broadening shows a pronounced mode
dependence. This observation is modeled in terms of two-magnon scattering
processes of the MSMs into the spin-wave manifold, mediated by surface and
volume defects.",1612.02360v1
2016-12-08,Stable Collective Dynamics of Two-Level Systems Coupled by Dipole Interactions,"We study the dynamics of a set of two-level systems coupled by dipolar
interactions under a resonant external Rabi drive. The two-level systems are
prepared initially in a coherent product state, and we ask how the
non-equilibrium conditions caused by the drive affect this coherence. We study
the full non-linear dynamics of the coupled two-level systems within a
classical approximation by analysing numerically the equations of motion and
determining the stability of the collective coherent state within classical
Floquet theory. We establish the behaviour analytically in the high Rabi
coupling limit by employing a Magnus expansion and spin wave analysis. Our
results show that, typically, the dipole interactions between the two-level
systems lead to instabilities that cause a breakdown of the collective Rabi
oscillations. However, we identify parameter regimes for which the two-level
systems undergo collective coherent Rabi oscillations even in the presence of
the dipole interactions.",1612.02595v2
2017-10-06,On-demand semiconductor source of 780 nm single photons with controlled temporal wave packets,"We report on a fast, bandwidth-tunable single-photon source based on an
epitaxial GaAs quantum dot. Exploiting spontaneous spin-flip Raman transitions,
single photons at $780\,$nm are generated on-demand with tailored temporal
profiles of durations exceeding the intrinsic quantum dot lifetime by up to
three orders of magnitude. Second-order correlation measurements show a low
multi-photon emission probability ($g^{2}(0)\sim\,0.10-0.15$) at a generation
rate up to $10\,$MHz. We observe Raman photons with linewidths as low as
$200\,$MHz, narrow compared to the $1.1\,$GHz linewidth measured in resonance
fluorescence. The generation of such narrow-band single photons with controlled
temporal shapes at the rubidium wavelength is a crucial step towards the
development of an optimized hybrid semiconductor-atom interface.",1710.02490v1
2018-04-08,Optical cooling of magnons,"Inelastic scattering of light by spin waves generates an energy flow between
the light and magnetization fields, a process that can be enhanced and
controlled by concentrating the light in magneto-optical resonators. Here, we
model the cooling of a sphere made of a magnetic insulator, such as yttrium
iron garnet (YIG), using a monochromatic laser source. When the magnon
lifetimes are much larger than the optical ones, we can treat the latter as a
Markovian bath for magnons. The steady-state magnons are canonically
distributed with a temperature that is controlled by the light intensity. We
predict that such a cooling process can significantly reduce the temperature of
the magnetic order within current technology.",1804.02683v1
2018-04-13,Gauge Assisted Quadratic Gravity: A Framework for UV Complete Quantum Gravity,"We discuss a variation of quadratic gravity in which the gravitational
interaction remains weakly coupled at all energies, but is assisted by a
Yang-Mills gauge theory which becomes strong at the Planck scale. The
Yang-Mills interaction is used to induce the usual Einstein-Hilbert term, which
was taken to be small or absent in the original action. We study the spin-two
propagator in detail, with a focus on the high mass resonance which is shifted
off the real axis by the coupling to real decay channels. We calculate
scattering in the $J=2$ partial wave and show explicitly that unitarity is
satisfied. The theory will in general have a large cosmological constant and we
study possible solutions to this, including a unimodular version of the theory.
Overall, the theory satisfies our present tests for being a ultraviolet
completion of quantum gravity.",1804.04980v1
2019-03-18,Thermal Hall Effect Induced by Magnon-Phonon Interactions,"We propose a new mechanism for the thermal Hall effect in exchange spin-wave
systems, which is induced by the magnon-phonon interaction. Using symmetry
arguments, we first show that this effect is quite general, and exists whenever
the mirror symmetry in the direction of the magnetization is broken. We then
demonstrate our result in a collinear ferromagnet on a square lattice, with
perpendicular easy-axis anisotropy and Dzyaloshinskii-Moriya interaction from
mirror symmetry breaking. We show that the thermal Hall conductivity is
controlled by the resonant contribution from the anti-crossing points between
the magnon and phonon branches, and estimate its size to be comparable to that
of the magnon mediated thermal Hall effect.",1903.07702v2
2020-09-24,Magnetic anisotropy and exchange paths for octa- and tetrahedrally coordinated Mn$^{2+}$ ions in the honeycomb multiferroic Mn$_2$Mo$_3$O$_8$,"We investigated the static and dynamic magnetic properties of the polar
ferrimagnet Mn$_2$Mo$_3$O$_8$ in three magnetically ordered phases via
magnetization, magnetic torque, and THz absorption spectroscopy measurements.
The observed magnetic field dependence of the spin-wave resonances, including
Brillouin zone-center and zone-boundary excitations, magnetization, and torque,
are well described by an extended two-sublattice antiferromagnetic classical
mean-field model. In this orbitally quenched system, the competing weak
easy-plane and easy-axis single-ion anisotropies of the two crystallographic
sites are determined from the model and assigned to the tetra- and octahedral
sites, respectively, by ab initio calculations.",2009.11683v1
2021-02-09,Quantum dynamics of Mn$^{2+}$ in dimethylammonium magnesium formate,"Dimethylammonium magnesium formate, [(CH$_3$)$_2$NH$_2$][Mg(HCOO)$_3$] or
DMAMgF, is a model to study high temperature hybrid perovskite-like
dielectrics. This compound displays a phase transition from para to
ferroelectric at about 260~K. Using multifrequency electron spin resonance in
continuous wave and pulsed modes, we herein present the quantum dynamic of
Mn$^{2+}$ ion probe in DMAMgF. In the high temperature paraelectric phase, we
observe a large distribution of the zero field splitting that is attributed to
high local disorder and further supported by DFT computations. In the low
temperature ferroelectric phase, a single structure phase is detected and shown
to contain two magnetic structures. The complex EPR signals were identifed by
the means of Rabi oscillation method combined to crystal fields kernel density
estimation.",2102.04792v1
2021-04-20,The effective radius for production of baryon-antibaryon pairs from $ψ$ decays,"By using the covariant L-S Scheme for the partial wave analysis, we deduce
the ratios between the S-wave and D-wave contributions from the recent data of
$\psi(1^-) \to B_8(1/2^+) \bar{B}_8(1/2^-)$ from the BESIII collaboration. For
the $J/\psi\to \Lambda\bar{\Lambda}$ and $J/\psi(\psi(2S))\to
\Sigma^{+}\bar{\Sigma}^{-}$, the ratios are fixed and the average angular
momenta are computed to estimate the effective radii of these processes. The
results show that the effective radii of these decays of $J/\psi(\psi(2S))$ are
very small, which are around 0.04 fm. Thus, it is a nice place to search
excited baryon resonances with lower spin in the decays of $J/\psi(\psi(2S))$.
Furthermore, for the other $\psi(1^-) \to B_8(1/2^+) \bar{B}_8(1/2^-)$
reactions, we propose some methods to get such effective radius.",2104.09908v1
2021-04-26,A unified theory of spin and charge excitations in high-$T_c$ cuprates: Quantitative comparison with experiment and interpretation,"We provide a unified interpretation of both paramagnon and plasmon modes in
high-$T_c$ copper-oxides, and verify it quantitatively against available
resonant inelastic $x$-ray scattering (RIXS) data across the hole-doped phase
diagram. Three-dimensional extended Hubbard model, with included long-range
Coulomb interactions and doping-independent microscopic parameters for both
classes of quantum fluctuations, is used. Collective modes are studied using
VWF+$1/\mathcal{N}_f$ approach which extends variational wave function (VWF)
scheme by means of an expansion in inverse number of fermionic flavors
($1/\mathcal{N}_f$). We show that intense paramagnons persist along the
anti-nodal line from the underdoped to overdoped regime and undergo rapid
overdamping in the nodal direction. Plasmons exhibit a three-dimensional
character, with minimal energy corresponding to anti-phase oscillations on
neighboring $\mathrm{CuO_2}$ planes. The theoretical spin- and charge
excitation energies reproduce semi-quantitatively RIXS data for $\mathrm{(Bi,
Pb)_2 (Sr, La)_2 CuO_{6+\delta}}$. The present VWF+$1/\mathcal{N}_f$ analysis
of dynamics and former VWF results for static quantities combine into a
consistent description of the principal properties of hole-doped high-$T_c$
cuprates as strongly correlated systems.",2104.12812v1
2021-10-05,The impact of defects on excitations in two-dimensional bipartite uniaxial antiferromagnet insulators,"We address scatterings of spin waves off uncorrelated defects in
two-dimensional (2D) easy-axis antiferromagnet (AFM) insulators. Although an
onsite magnetic anisotropy leads gapped Goldstone modes, such that a long range
(AFM) order can be established in 2D, lattice imperfections tend to weaken, and
eventually destroy the magnetic ordering. Here, the impact of defects is
considered within two limits, single and multiple defects. Using Green's
function, we perform self consistent simulations to study magnon properties
such as density of states and lifetime of induced resonances. Our findings show
that repulsive defects decrease the magnon density of states while attractive
ones may enhance it. We provide a comprehensive analysis of how defects can
result in a reduction and even closing, the anisotropy induced gap, which
weakens the long range (AFM) order parameter in the 2D state. We conclude that
a small concentration of random defects can fill the gap of magnon spectrum.",2110.02045v3
2016-11-02,Preservation of quantum correlations in femtosecond light pulse train within atomic ensemble,"In this paper, we examined a possibility of preservation of a substantially
multimode radiation in a single cell of quantum memory. As a light source we
considered a synchronously pumped optical parametric oscillator (SPOPO). As it
was shown in [1-4], SPOPO radiation has a large number of the correlated modes
making it attractive for the purposes of the quantum communication and
computing. We showed that these correlations can be mapped on the longitudinal
spin waves of the memory cell and be restored later in the readout light. The
efficiencies of the writing and readout depend on the mode structure of the
memory determined by a mechanism of the light-matter interaction under
consideration (the non-resonance Raman interaction) and by the profile of the
driving light field. We showed that like the initial light pulse train, the
restored one can be represented by a set of squeezed supermodes. The mapping of
the quantum multimode correlations on the material medium offers opportunities
to manipulate the quantum states within the memory cell followed by the reading
of the transformed state.",1611.00703v1
2017-02-19,Model-independent partial wave analysis using a massively-parallel fitting framework,"The functionality of GooFit, a GPU-friendly framework for doing
maximum-likelihood fits, has been extended to extract model-independent S-wave
amplitudes in three-body decays such as $D^+ \to h^+h^+h^-$. A full amplitude
analysis is done where the magnitudes and phases of the S-wave amplitudes are
anchored at a finite number of $m^2(h^+h^-)$ control points, and a cubic spline
is used to interpolate between these points. The amplitudes for P-wave and
D-wave intermediate states are modeled as spin-dependent Breit-Wigner
resonances. GooFit uses the Thrust library, with a CUDA backend for NVIDIA GPUs
and an OpenMP backend for threads with conventional CPUs. Performance on a
variety of platforms is compared. Executing on systems with GPUs is typically a
few hundred times faster than executing the same algorithm on a single CPU.",1703.03284v1
2017-03-23,Antireflective photonic structure for coherent nonlinear spectroscopy of single magnetic quantum dots,"This work presents epitaxial growth and optical spectroscopy of CdTe quantum
dots (QDs) in (Cd,Zn,Mg)Te barriers placed on the top of (Cd,Zn,Mg)Te
distributed Bragg reflector. The formed photonic mode in our half-cavity
structure permits to enhance the local excitation intensity and extraction
efficiency of the QD photoluminescence, while suppressing the reflectance
within the spectral range covering the QD transitions. This allows to perform
coherent, nonlinear, resonant spectroscopy of individual QDs. The coherence
dynamics of a charged exciton is measured via four-wave mixing, with the
estimated dephasing time $T_2=(210\,\pm\,40)$ ps. The same structure contains
QDs doped with single Mn$^{2+}$ ions, as detected in photoluminescence spectra.
Our work therefore paves the way toward investigating and controlling an
exciton coherence coupled, via $s$,$p$-$d$ exchange interaction, with an
individual spin of a magnetic dopant.",1703.08062v1
2019-01-23,Characterization of photoexcited states in the half-filled one-dimensional extended Hubbard model assisted by machine learning,"Photoinduced nonequilibrium states can provide new insight into dynamical
properties of strongly correlated electron systems. One of the typical and
extensively studied systems is the half-filled one-dimensional extended Hubbard
model (1DEHM). Here, we propose that the supervised machine learning (ML) can
provide useful information for characterizing photoexcited states in 1DEHM.
Using entanglement spectra as a training dataset, we construct neural network.
Judging from the trained network, we find that bond-spin-density wave (BSDW)
order can be enhanced in photoexcited states if the frequency of a driving
pulse nearly resonates with gap. We separately calculate the time evolution of
local and non-local order parameters and confirm that the correlation functions
of BSDW are actually enhanced by photoexcitation as predicted by ML. The
successful prediction of BSDW demonstrates the advantage of ML to assist
characterizing photoexcited quantum states.",1901.07900v3
2019-04-17,Power narrowing: Counteracting Doppler broadening in two-color transitions,"Doppler broadening in thermal ensembles degrades the absorption cross-section
and the coherence time of collective excitations. In two photon transitions, it
is common to assume that this problem becomes worse with larger wavelength
mismatch. Here we identify an opposite mechanism, where such wavelength
mismatch leads to cancellation of Doppler broadening via the counteracting
effects of velocity-dependent light-shifts and Doppler shifts. We show that
this effect is general, common to both absorption and transparency resonances,
and favorably scales with wavelength mismatch. We experimentally confirm the
enhancement of transitions for different low-lying orbitals in rubidium atoms
and use calculations to extrapolate to high-lying Rydberg orbitals. These
calculations predict a dramatic enhancement of up to 20-fold increase in
absorption, even in the presence of large homogeneous broadening. More general
configurations, where an auxiliary dressing field is used to counteract Doppler
broadening, are also discussed and experimentally demonstrated. The mechanism
we study can be applied as well for rephasing of spin waves and increasing the
coherence time of quantum memories.",1904.08529v2
2019-07-19,Enhanced E1 transition between weakly-bound excited states in the nucleus 27Ne,"Inspired by the recently-reported strong electric-dipole (E1) transition
between the weakly-bound first and second excited states, 3/2- at 765 keV and
1/2+ at 885 keV, in the nucleus 27Ne, the E1 transition is estimated in a model
by properly taking into account the effect of both deformation and weakly-bound
neutrons. In addition to both the spin-parities, 1/2+ and 3/2-, and observed
nearly degenerate energies of the two excited states, the observed order of
magnitude of the E1 transition strength between the two states is very
naturally explained in the case that these two excited states are prolately
deformed, in terms of the transitions between the halo components of the wave
functions of the weakly-bound odd-neutrons, s1/2 -> p3/2 and s1/2 -> p1/2, in
addition to the large probability of the p3/2 component in the weakly-bound
neutron [330 1/2] orbit. The large probability is the result of the
shell-structure unique in weakly-bound or resonant neutrons.",1907.08460v1
2019-09-12,Magnetostrictively induced stationary entanglement between two microwave fields,"We present a scheme to entangle two microwave fields by using the nonlinear
magnetostrictive interaction in a ferrimagnet. The magnetostrictive interaction
enables the coupling between a magnon mode (spin wave) and a mechanical mode in
the ferrimagnet, and the magnon mode simultaneously couples to two microwave
cavity fields via the magnetic dipole interaction. The magnon-phonon coupling
is enhanced by directly driving the ferrimagnet with a strong red-detuned
microwave field, and the driving photons are scattered onto two sidebands
induced by the mechanical motion. We show that two cavity fields can be
prepared in a stationary entangled state if they are respectively resonant with
two mechanical sidebands. The present scheme illustrates a new mechanism for
creating entangled states of optical fields, and enables potential applications
in quantum information science and quantum tasks that require entangled
microwave fields.",1909.05936v3
2020-06-15,Anomalous helimagnetic domain shrinkage due to the weakening of Dzyaloshinskii-Moriya interaction in CrAs,"CrAs is a well-known helimagnet with the double-helix structure originating
from the competition between the Dzyaloshinskii-Moriya interaction (DMI) and
antiferromagnetic exchange interaction $J$. By resonant soft X-ray scattering
(RSXS), we observe the magnetic peak (0~0~$q_m$) that emerges at the helical
transition with $T_S$ $\approx$ 267.5 K. Intriguingly, the helimagnetic domains
significantly shrink on cooling below $\sim$255 K, opposite to the conventional
thermal effect. The weakening of DMI on cooling is found to play a critical
role here. It causes the helical wave vector to vary, ordered spins to rotate,
and extra helimagnetic domain boundaries to form at local defects, thus leading
to the anomalous shrinkage of helimagnetic domains. Our results indicate that
the size of magnetic helical domains can be controlled by tuning DMI in certain
helimagnets.",2006.08534v1
2020-10-12,Nonmagnetic-magnetic transition and magnetically ordered structure in SmS,"SmS, a prototypical intermediate valence compound, has been studied by
performing high-pressure nuclear magnetic resonance measurements on a
$^{33}$S-enriched sample. The observation of an additional signal below 15-20 K
above a nonmagnetic-magnetic transition pressure $P_{\rm c2} \approx 2$ GPa
gives evidence of a magnetic transition. The absence of a Curie-term in the
Knight shift near $P_{\rm c2}$ indicates that the localized character of $4f$
electrons is entirely screened and the mechanism of the magnetic ordering is
not described within a simple localized model. Simultaneously, the line shape
in the magnetically ordered state is incompatible with a spin density wave
order. These suggest that the magnetic order in SmS may require an
understanding beyond the conventional framework for heavy fermions. The fact
that hyperfine fields from the ordered moments cancel out at the S site leads
us to a conclusion that the ordered phase has a type II antiferromagnetic
structure.",2010.05539v2
2021-01-26,Superradiant detection of microscopic optical dipolar interactions,"The interaction between light and cold atoms is a complex phenomenon
potentially featuring many-body resonant dipole interactions. A major obstacle
toward exploring these quantum resources of the system is macroscopic light
propagation effects, which not only limit the available time for the
microscopic correlations to locally build up, but also create a directional,
superradiant emission background whose variations can overwhelm the microscopic
effects. In this Letter, we demonstrate a method to perform ``background-free''
detection of the microscopic optical dynamics in a laser-cooled atomic
ensemble. This is made possible by transiently suppressing the macroscopic
optical propagation over a substantial time, before a recall of superradiance
that imprints the effect of the accumulated microscopic dynamics into an
efficiently detectable outgoing field. We apply this technique to unveil and
precisely characterize a density-dependent, microscopic dipolar dephasing
effect that generally limits the lifetime of optical spin-wave order in
ensemble-based atom-light interfaces.",2101.10779v2
2021-09-29,Generation of topologically complex three-dimensional electron beams in a plasma photocathode,"Laser-triggered ionization injection is a promising way of generating
controllable high-quality electrons in plasma-based acceleration. We show that
ionization injection of electrons into a fully nonlinear plasma wave wake using
a laser pulse comprising of one or more Laguerre-Gaussian modes with
combinations of spin and orbital angular momentum can generate exotic
three-dimensional (3D) spatial distributions of high-quality relativistic
electrons. The phase dependent residual momenta and initial positions of the
ionized electrons are encoded into their final phase space distributions,
leading to complex spatiotemporal structures. The structures are formed as a
result of the transverse (betatron) and longitudinal (phase slippage and energy
gain) dynamics of the electrons in the wake immediately after the electrons are
injected. Theoretical analysis and 3D simulations verify this mapping process
leads to the generation of these complex topological beams. These beams may
trigger novel beam-plasma interactions as well as produce coherent radiation
with orbital angular momentum when sent through a resonant undulator.",2109.14566v1
2021-12-08,Elastic $π-N$ scattering in the $I=3/2$ channel,"We present our study of $\pi-N$ scattering in the iso-spin $I=3/2$ channel
for the first time at the physical point. The calculation is performed using
$N_f=2+1+1$ flavors of twisted mass fermions with clover improvement at
physical pion mass. We compute energy levels for the rest frame and moving
frames up to a total momentum of $|\vec{P}|=\sqrt{3} \,\frac{2\pi}{L}$, and for
all the relevant ireducible representations of the lattice symmetry groups. We
perform a phase-shift analysis including $s\,(\ell=0)$ and $p\,(\ell=1)$ wave
phase shifts assuming a Breit-Wigner form and determine the parameters of the
$\Delta$ resonance.",2112.04146v1
2022-02-24,Nanodiamonds based optical-fiber quantum probe for magnetic field and biological sensing,"Owing to the unique electronic spin properties, the nitrogen-vacancy (NV)
centers hosted in diamond have emerged as a powerful quantum sensor for various
physical parameters and biological species. In this work, a miniature
optical-fiber quantum probe, configured by chemically-modifying nanodiamonds NV
centers on the surface of a cone fiber tip, is developed. Based on
continue-wave optically detected magnetic resonance method and lock-in
amplifying technique, it is found that the sensing performance of the probe can
be engineered by varying the nanodiamonds dispersion concentration and
modification duration in the chemical modification process. Combined with a
pair of magnetic flux concentrators, the magnetic field detection sensitivity
of the probe is significantly enhanced to 0.57 nT/Hz1/2 @ 1Hz, a new record
among the fiber magnetometers based on nanodiamonds NV. Taking Gd3+ as the
demo, the capability of the probe in paramagnetic species detection is also
demonstrated experimentally. Our work provides a new approach to develop NV
center as quantum probe featuring high integration, miniature size,
multifunction, and high sensitivity, etc.",2202.11859v2
2022-04-05,Thermodynamic insights into the intricate magnetic phase diagram of EuAl$_{4}$,"The tetragonal intermetallic compound EuAl$_{4}$ hosts an exciting variety of
low temperature phases. In addition to a charge density wave below 140 K, four
ordered magnetic phases are observed below 15.4 K. Recently, a skyrmion phase
was proposed based on Hall effect measurements under a $c$-axis magnetic field.
We present a detailed investigation of the phase transitions in EuAl$_{4}$
under $c$-axis magnetic field. Our dilatometry, heat capacity, DC magnetometry,
AC magnetic susceptibility, and resonant ultrasound spectroscopy measurements
reveal three magnetic phase transitions not previously reported. We discuss
what our results reveal about the character of the magnetic phases. Our first
key result is a detailed $H \parallel [001]$ magnetic phase diagram mapping the
seven phases we observe. Second, we identify a new high-field phase, phase VII,
which directly corresponds to the region were skyrmions have been suggested.
Our results provide guidance for future studies exploring the complex magnetic
interactions and spin structures in EuAl$_{4}$.",2204.02319v1
2022-07-27,Polarization-decoupled Flat Displays,"Many modern applications like entertainment displays, data encryption,
security, and virtual reality (VR) technology require asymmetric light
manipulation. Symmetric spin-orbit interactions (SOI) apply a limit in
achieving an asymmetrical metahologram. However, different reported asymmetric
SOI's based on propagation and geometric phase mergence techniques effectively
break this limit at the expense of design complexity and greater computation
cost. This work proposes a novel helicity multiplexing technique that breaks
all the aforementioned barriers in achieving on-axis dual side holograms.
Benefiting from the geometric phase modulation of anisotropic nano-resonating
antennas, we have employed a single unit cell to achieve helicity multiplexing.
A low extinction coefficient material a-Si:H is used for device analysis. Due
to the simple single unit cell-based designing technique, simulation and
fabrication complexities were significantly reduced. As a result, based on the
helicity and incidence direction of electromagnetic wave, we have achieved
highly transmissive dual holographic images in the visible band. Our simulated
efficiencies are 55%, 75%, and 80% for the blue ({\lambda} = 488 nm), green
({\lambda} = 532 nm), and red light ({\lambda} = 633 nm).",2207.13810v1
2022-09-29,Study of Charmonium(-like) Spectroscopy and Decay at BESIII,"The recent results on Charmonium and Charmonium-like states at BESIII are
reviewed, including the observation of $\rm Z_{cs}(3985)$ state, the study of
the new decay modes of $\psi_2(3823)$ state, observation of resonance structure
in $\rm e^+e^- \to \pi^+\pi^-\psi_2(3823)$ process, the study of the $\rm
e^+e^- \to K^+K^-J/\psi$ process, cross section measurement of $\rm e^+e^- \to
\omega\pi^0$ and $\omega\eta$ process, branching fraction measurement of
$\psi(3686)\to\bar{\Sigma}^0\Lambda + c.c.$ process. Decay channels for
$\chi_{cJ} \to \Lambda\bar{\Lambda}$, $\chi_{cJ} \to \Lambda\bar{\Lambda}\eta$,
$\psi(3686) \to \Lambda\bar{\Lambda}\omega$ and $\eta_c(2S)\to3(\pi^+\pi^-)$
are also discussed. The property of the spin singlet P wave Charmonium state,
$\rm h_c$ is also reported.",2209.15061v2
2022-12-02,Cavity-mediated coupling of antiferromagnetic spin waves,"Coupling of space-separated oscillators is interesting for quantum and
communication technologies. In this work, it is shown that two
antiferromagnetic oscillators placed inside an electromagnetic cavity couple
cooperatively to its terahertz modes and, in effect, hybridized
magnon-polariton modes are formed. This is supported by a systematic study of
reflection spectra from two parallel-plane slabs of hematite
($\alpha$-Fe$_2$O$_3$), measured as a function of their temperatures and
separation distance, and modeled theoretically. The mediating cavity was formed
by the crystals themselves and the experiment was performed in a practical
distance range of a few millimetres and above room temperature. Cavity-mediated
coupling allows for engineering of complex resonators controlled by their
geometry and by sharing properties of their components.",2212.01129v1
2022-12-11,Manifestation of the coupling phase in microwave cavity magnonics,"The interaction between microwave photons and magnons is well understood and
originates from the Zeeman coupling between spins and a magnetic field.
Interestingly, the magnon/photon interaction is accompanied by a phase factor
which can usually be neglected. However, under the rotating wave approximation,
if two magnon modes simultaneously couple with two cavity resonances, this
phase cannot be ignored as it changes the physics of the system. We consider
two such systems, each differing by the sign of one of the magnon/photon
coupling strengths. This simple difference, originating from the various
coupling phases in the system, is shown to preserve, or destroy, two potential
applications of hybrid photon/magnon systems, namely dark mode memories and
cavity-mediated coupling. The observable consequences of the coupling phase in
this system is akin to the manifestation of a discrete Pancharatnam-Berry
phase, which may be useful for quantum information processing.",2212.05389v1
2023-02-20,Optimizing the magnon-phonon cooperativity in planar geometries,"Optimizing the cooperativity between two distinct particles is an important
feature of quantum information processing. Of particular interest is the
coupling between spin and phonon, which allows for integrated long range
communication between gates operating at GHz frequency. Using local light
scattering, we show that, in magnetic planar geometries, this attribute can be
tuned by adjusting the orientation and strength of an external magnetic field.
The coupling strength is enhanced by about a factor of 2 for the out-of-plane
magnetized geometry where the Kittel mode is coupled to circularly polarized
phonons, compared to the in-plane one where it couples to linearly polarized
phonons. We also show that the overlap between magnon and phonon is maximized
by matching the Kittel frequency with an acoustic resonance that satisfies the
half-wave plate condition across the magnetic film thickness. Taking the
frequency dependence of the damping into account, a maximum cooperativity of
about 6 is reached in garnets for the normal configuration near 5.5 GHz.",2302.09936v2
2024-01-11,Solid-state continuous time crystal with a built-in clock,"Time crystals (TCs) are many-body systems displaying spontaneous breaking of
time translation symmetry. Here, we demonstrate a TC using driven-dissipative
condensates of microcavity exciton-polaritons, spontaneously formed from an
incoherent particle bath. In contrast to other realizations, the TC phases can
be controlled by the power of continuous-wave non-resonant optical drive
exciting the condensate and optomechanical interactions with phonons. Those
phases are for increasing power: (i) Larmor precession of pseudo-spins - a
signature of continuous TC, (ii) locking of the frequency of precession to
self-sustained coherent phonons - stabilized TC, (iii) doubling of TC frequency
by phonons - a discrete TC with continuous excitation. These results establish
microcavity polaritons as a platform for the investigation of time-broken
symmetry in non-hermitian systems.",2401.06246v1
2024-02-18,C. V. Vishveshwara (Vishu) On The Black Hole Trek,"With his seminal and pioneering work on the stability of the Schwarzschild
black hole and its interaction with gravitational radiation, Vishu had opened a
new window on black hole astrophysics. One of the interesting results that soon
followed was that ""a black hole has no hair"", it is entirely specified by the
three parameters, mass, spin and charge, and nothing more. The discovery of
gravitational waves in 2016 produced by merger of two black holes, and observed
by the Ligo-Virgo collaboration, carried the definitive signature of
quasi-normal modes, the phenomenon of black hole ringdown, exactly what Vishu
had predicted in his 1970 Nature paper~(See Isaacson's commentary) 46 years
ago. This was the crowning glory.",2402.11503v1
2024-02-26,Distinct Optical Excitation Mechanisms of a Coherent Magnon in a van der Waals Antiferromagnet,"The control of antiferromagnets with ultrashort optical pulses has emerged as
a prominent field of research. Tailored laser excitation can launch coherent
spin waves at terahertz frequencies, yet a comprehensive description of their
generation mechanisms is still lacking despite extensive efforts. Using
terahertz emission spectroscopy, we investigate the generation of a coherent
magnon mode in the van der Waals antiferromagnet NiPS$_3$ under a range of
photoexcitation conditions. By tuning the pump photon energy from transparency
to resonant with a $d$-$d$ transition, we reveal a striking change in the
coherent magnon's dependence on the pump polarization, indicating two distinct
excitation mechanisms. Our findings provide a strategy for the manipulation of
magnetic modes via photoexcitation around sub-gap electronic states.",2402.17041v2
2024-03-05,Incommensurate broken-helix and broken-fanlike states in axion insulator candidate EuIn$_{2}$As$_{2}$,"Zintl phase EuIn$_{2}$As$_{2}$ has garnered growing attention as an axion
insulator candidate, triggered by the identification of a commensurate
double-${\mathbf Q}$ broken-helix state in previous studies, however, its
periodicity and symmetry remain subjects of debate. Here, we perform resonant
x-ray scattering experiments on EuIn$_{2}$As$_{2}$, revealing an incommensurate
nature of the broken-helix state, where both the wave number and the amplitude
of the helical modulation exhibit systematic sample dependence. Furthermore,
the application of an in-plane magnetic field brings about a broken-fanlike
state preserving the double-${\mathbf Q}$ nature, which could be attributed to
multiple-spin interactions in momentum space. We propose that the itinerant
character of EuIn$_{2}$As$_{2}$, possibly induced by Eu deficiency, gives rise
to the helical modulation and impedes the realization of a
theoretically-predicted axion state with the collinear antiferromagnetic order.",2403.03022v1
2024-03-26,A new double-pass type of the optical spring,"In detuned optical cavities, the radiation pressure force acting on the
mirrors depends on their displacements. This is equivalent to the rigidity (the
optical spring), inserted between the mirrors. This effect can be used for
optimization of the mechanical susceptibility of probe mirrors in
high-precision force sensors. However, in some cases, the use of detuned
cavities or even just any high-finesse cavities could be problematic due to
technological constraints.
  We consider a new type of the optical spring that does not require the cavity
(but can use a resonance tuned one to increase the optomechanical coupling).
Instead, it uses the double interaction of the probing light with the
mechanical object. We propose two possible implementation of this concept,
suitable, respectively, for the atomic spin ensembles and for the laser
gravitational-wave detectors.",2403.17795v1
2011-11-15,Resonances in Extreme Mass-Ratio Inspirals: Asymptotic and Hyperasymptotic Analysis,"An expected source of gravitational waves for future detectors in space are
the inspirals of small compact objects into much more massive black holes.
These sources have the potential to provide a wealth of information about
astronomy and fundamental physics. On short timescales the orbit of the small
object is approximately geodesic. Generic geodesics for a Kerr black hole
spacetime have a complete set of integrals and can be characterized by three
frequencies of the motion. Over the course of an inspiral, a typical system
will pass through resonances where two of these frequencies become
commensurate. The effect of the resonance will be to alter significantly the
rate of inspiral for the duration of the resonance. Understanding the impact of
these resonances on gravitational wave phasing is important to detect and
exploit these signals for astrophysics and fundamental physics. Two
differential equations that might describe the passage of an inspiral through
such a resonance are investigated. These differ depending on whether it is the
phase or the frequency components of a Fourier expansion of the motion that are
taken to be continuous through the resonance. Asymptotic and hyperasymptotic
analysis are used to find the late-time analytic behavior of the solution for a
system that has passed through a resonance. Linearly growing (weak resonances)
or linearly decaying (strong resonances) solutions are found depending on the
strength of the resonance. In the weak-resonance case, frequency resonances
leave an imprint (a resonant memory) on the gravitational frequency evolution.
The transition between weak and strong resonances is characterized by a
square-root singularity, and as one approaches this transition from above, the
solutions to the frequency resonance equation bunch up into families
exponentially fast.",1111.3605v1
2012-02-08,"Coherent, mechanical control of a single electronic spin","The ability to control and manipulate spins via electrical, magnetic and
optical means has generated numerous applications in metrology and quantum
information science in recent years. A promising alternative method for spin
manipulation is the use of mechanical motion, where the oscillation of a
mechanical resonator can be magnetically coupled to a spins magnetic dipole,
which could enable scalable quantum information architectures9 and sensitive
nanoscale magnetometry. To date, however, only population control of spins has
been realized via classical motion of a mechanical resonator. Here, we
demonstrate coherent mechanical control of an individual spin under ambient
conditions using the driven motion of a mechanical resonator that is
magnetically coupled to the electronic spin of a single nitrogen-vacancy (NV)
color center in diamond. Coherent control of this hybrid mechanical/spin system
is achieved by synchronizing pulsed spin-addressing protocols (involving
optical and radiofrequency fields) to the motion of the driven oscillator,
which allows coherent mechanical manipulation of both the population and phase
of the spin via motion-induced Zeeman shifts of the NV spins energy. We
demonstrate applications of this coherent mechanical spin-control technique to
sensitive nanoscale scanning magnetometry.",1202.1823v1
2019-10-24,Radiative cooling of a spin ensemble,"Physical systems reach thermal equilibrium through energy exchange with their
environment, and for spins in solids the relevant environment is almost always
the host lattice in which they sit. However, recent studies motivated by
observations from Purcell showed how coupling to a cavity can become the
dominant form of relaxation for spins, given suitably strong spin-cavity
coupling. In this regime, the cavity electromagnetic field takes over from the
lattice as the dominant environment, inviting the prospect of controlling the
spin temperature independently from that of the lattice, by engineering a
suitable cavity field. Here, we report on precisely such control over spin
temperature, illustrating a novel and universal method of electron spin
hyperpolarisation. By switching the cavity input between loads at different
temperatures we can control the electron spin polarisation, cooling it below
the lattice temperature. Our demonstration uses donor spins in silicon coupled
to a superconducting micro-resonator and we observe an increase of spin
polarisation of over a factor of two. This approach provides general route to
signal enhancement in electron spin resonance, or indeed nuclear magnetic
resonance through dynamical nuclear spin polarisation (DNP).",1910.11092v1
2006-01-27,Spin-orbit effects on the Larmor dispersion relation in GaAs quantum wells,"We have studied the relevance of spin-orbit coupling to the dispersion 00009
relation of the Larmor resonance observed in inelastic light scattering and
electron-spin resonance experiments on GaAs quantum wells. We show that the
spin-orbit interaction, here described by a sum of Dresselhaus and
Bychkov-Rashba terms, couples Zeeman and spin-density excitations. We have
evaluated its contribution to the spin splitting as a function of the magnetic
field $B$, and have found that in the small $B$ limit, the spin-orbit
interaction does not contribute to the spin splitting, whereas at high magnetic
fields it yields a $B$ independent contribution to the spin splitting given by
$2(\lambda_R^2-\lambda_D^2)$, with $\lambda_{R,D}$ being the intensity of the
Bychkov-Rashba and Dresselhaus spin-orbit terms.",0601635v1
2008-05-08,Electrically driven single electron spin resonance in a slanting Zeeman field,"The rapidly rising fields of spintronics and quantum information science have
led to a strong interest in developing the ability to coherently manipulate
electron spins. Electron spin resonance (ESR) is a powerful technique to
manipulate spins that is commonly achieved by applying an oscillating magnetic
field. However, the technique has proven very challenging when addressing
individual spins. In contrast, by mixing the spin and charge degrees of freedom
in a controlled way through engineered non-uniform magnetic fields, electron
spin can be manipulated electrically without the need of high-frequency
magnetic fields. Here we realize electrically-driven addressable spin rotations
on two individual electrons by integrating a micron-size ferromagnet to a
double quantum dot device. We find that the electrical control and spin
selectivity is enabled by the micro-magnet's stray magnetic field which can be
tailored to multi-dots architecture. Our results demonstrate the feasibility of
manipulating electron spins electrically in a scalable way.",0805.1083v1
2010-12-23,Electrical Detection of Coherent Nuclear Spin Oscillations in Phosphorus-Doped Silicon Using Pulsed ENDOR,"We demonstrate the electrical detection of pulsed X-band Electron Nuclear
Double Resonance (ENDOR) in phosphorus-doped silicon at 5\,K. A pulse sequence
analogous to Davies ENDOR in conventional electron spin resonance is used to
measure the nuclear spin transition frequencies of the $^{31}$P nuclear spins,
where the $^{31}$P electron spins are detected electrically via spin-dependent
transitions through Si/SiO$_2$ interface states, thus not relying on a
polarization of the electron spin system. In addition, the electrical detection
of coherent nuclear spin oscillations is shown, demonstrating the feasibility
to electrically read out the spin states of possible nuclear spin qubits.",1012.5241v1
2013-08-12,Electron Spin Resonance in Quasi-One-Dimensional Quantum Antiferromagnets: Relevance of Weak Interchain Interactions,"We discuss universal features on the electron spin resonance (ESR) of a
temperature-induced Tomonaga-Luttinger liquid phase in a wide class of weakly
coupled $S=1/2$ antiferromagnetic spin chains such as spin ladders, spin tubes
and three-dimensionally coupled spin chains. We show that the ESR linewidth of
various coupled chains increases with lowering temperature while the linewidth
of a single spin chain is typically proportional to temperature. This
broadening with lowering temperature is attributed to anisotropic interchain
interactions and has been indeed observed in several kinds of three-dimensional
(3D) magnets of weakly coupled spin chains above the 3D ordering temperature.
We demonstrate that our theory can account for anomalous behaviors of the
linewidths in an $S=1/2$ four-leg spin tube compound Cu$_2$Cl$_4 \cdot
$H$_8$C$_4$SO$_2$ (abbreviated to Sul-Cu$_2$Cl$_4$) and a three-dimensionally
coupled $S=1/2$ spin chain compound CuCl$_2\cdot 2$NC$_5$H$_5$.",1308.2714v2
2014-08-25,Spin-Scattering Rates in Metallic Thin Films Measured by Ferromagnetic Resonance Damping Enhanced by Spin-Pumping,"We determined the spin-transport properties of Pd and Pt thin films by
measuring the increase in ferromagnetic resonance damping due to spin-pumping
in ferromagnetic (FM)-nonferromagnetic metal (NM) multilayers with varying NM
thicknesses. The increase in damping with NM thickness depends strongly on both
the spin- and charge-transport properties of the NM, as modeled by diffusion
equations that include both momentum- and spin-scattering parameters. We use
the analytical solution to the spin-diffusion equations to obtain
spin-diffusion lengths for Pt and Pd. By measuring the dependence of
conductivity on NM thickness, we correlate the charge- and spin-transport
parameters, and validate the applicability of various models for
momentum-scattering and spin-scattering rates in these systems: constant,
inverse-proportional (Dyakanov-Perel), and linear-proportional (Elliot-Yafet).
We confirm previous reports that the spin-scattering time can be shorter than
the momentum scattering time in Pt, and the Dyakanov-Perel-like model is the
best fit to the data.",1408.5921v2
2016-08-19,Temperature dependence of the electron spin resonance linewidth in magnetic insulators,"We analyze the temperature dependence of the electron spin resonance
linewidth above the critical region in exchange-coupled magnetic insulators.
The focus is on separating the contributions to the linewidth from spin-spin
interactions, spin-one-phonon interactions and spin-two-phonon interactions at
temperatures where the spin-spin term is constant and the one- and two-phonon
terms vary as T and T^2, respectively. Taking Co3O4 as an example, we use a
least squares fit over the temperature range 50 K < T < 500 K to obtain values
of the three components. It is found that the spin-spin mechanism is dominant
below 100 K, while the two-phonon mechanism is most important above 250 K. In
the intermediate region, all three mechanisms make significant contributions.",1608.05653v2
2018-09-28,Observation of magnetic-field-sweep-direction-dependent dynamic nuclear polarization under periodic optical electron spin pumping,"Optical pump-probe techniques are used to generate and measure electron spin
polarization in a gallium arsenide epilayer in which the electron spin
coherence time exceeds the mode-locked laser repetition period. Resonant spin
amplification occurs at magnetic fields at which the electron spin polarization
excited by successive laser pulses add constructively. Measurements of Kerr
rotation as a function of applied magnetic field reveal nuclear spin
polarization that aligns either with or against the external magnetic field
depending on whether the applied magnetic field is being decreased or
increased. Furthermore, the nuclear spin polarization magnitude varies in
proportion to the perpendicular net electron spin polarization as the latter
changes due to resonant spin amplification and other causes. We also report an
experimental technique that reveals a minutes-long memory of precise field
history in the electron-nuclear spin system.",1810.00055v2
2012-09-17,Detecting External Electron Spins Using Nitrogen-Vacancy Centers,"Near-surface nitrogen-vacancy (NV) centers have been created in diamond
through low energy implantation of 15N to sense electron spins that are
external to the diamond. By performing double resonance experiments, we have
verified the presence of g=2 spins on a diamond crystal that was subjected to
various surface treatments, including coating with a polymer film containing
the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Subsequent acid cleaning
eliminated the spin signal without otherwise disrupting the NV center,
providing strong evidence that the spins were at the surface. A clear
correlation was observed between the size of the detected spin signal and the
relaxation time T2 for the six NV centers studied. We have developed a model
that takes into account the finite correlation time of the fluctuating magnetic
fields generated by the external spins, and used it to infer the signal
strength and correlation time of the magnetic fields from these spins. This
model also highlights the sensitivity advantage of active manipulation of the
longitudinal spin component via double resonance over passive detection schemes
that measure the transverse component of spin.",1209.3748v1
2019-01-07,Simultaneous Optical and Electrical Spin-Torque Magnetometry with Stroboscopic Detection of Spin-Precession Phase,"Spin-based coherent information processing and encoding utilize the
precession phase of spins in magnetic materials. However, the detection and
manipulation of spin precession phases remain a major challenge for advanced
spintronic functionalities. By using simultaneous electrical and optical
detection, we demonstrate the direct measurement of the precession phase of
Permalloy ferromagnetic resonance driven by the spin-orbit torques from
adjacent heavy metals. The spin Hall angle of the heavy metals can be
independently determined from concurrent electrical and optical signals. The
stroboscopic optical detection also allows spatially measuring local
spin-torque parameters and the induced ferromagnetic resonance with
comprehensive amplitude and phase information. Our study offers a route towards
future advanced characterizations of spin-torque oscillators, magnonic
circuits, and tunnelling junctions, where measuring the current-induced spin
dynamics of individual nanomagnets are required.",1901.01923v1
2020-06-14,"MoS2 thin-film transistors spin-states, of conduction electrons and vacancies, distinguished by operando electron spin resonance","Transition metal dichalcogenide MoS2 is a two-dimensional material,
attracting much attention for next-generation applications thanks to rich
functionalities stemmed from the crystal structure. Many experimental and
theoretical works have focused on the spin-orbit interaction which couples the
valley and spin degree of freedom so that the spin-states can be electrically
controllable. However, the spin-states of charge carriers and vacancies have
not been yet elucidated directly from a microscopic viewpoint. We report the
spin-states in thin-film electric double-layer transistors using operando
electron spin resonance (ESR) spectroscopy. We have observed clearly different
ESR signals of the conduction electrons and vacancies, and distinguished the
corresponding spin-states from the signals and theoretical calculations,
evaluating the gate-voltage dependence and spin-susceptibility and g-factor
temperature dependence. This analysis gives deep insight into the MoS2
magnetism and clearly indicates the lower charge mobilities compared to
graphene, which would be useful for improvements of the device characteristics
and new applications.",2006.07842v1
2020-12-25,Spin-circuit representation of spin-torque ferromagnetic resonance,"Spin-torque ferromagnetic resonance (ST-FMR) particularly using magnetic
insulators and heavy metals possessing a giant spin Hall effect (SHE) has
gotten a lot of attention for the development of spintronic devices. To devise
complex functional devices, it is necessary to construct the equivalent
spin-circuit representations of different phenomena. Such representation is
useful to translate physical equations into circuit elements, benchmarking
experiments, and then proposing creative and efficient designs. We utilize the
superposition principle in circuit theory to separate the spin Hall
magnetoresistance and spin pumping contributions in the ST-FMR experiments. We
show that the proposed spin-circuit representation reproduces the standard
results in literature. We further consider multilayers like a spin-valve
structure with an SHE layer sandwiched by two magnetic layers and show how the
corresponding spin-circuit representation can be constructed by simply writing
a vector netlist and solved using circuit theory.",2012.13591v1
2021-03-10,Electric-dipole-induced resonance and decoherence of a dressed spin in a quantum dot,"Electron spin qubit in a quantum dot has been studied extensively for
scalable quantum information processing over the past two decades. Recently,
high-fidelity and fast single-spin control and strong spin-photon coupling have
been demonstrated using a synthetic spin-orbit coupling created by a
micromagnet. Such strong electrical driving suggests a strongly coupled
spin-photon system. Here we study the relaxation, pure dephasing, and
electrical manipulation of a dressed-spin qubit based on a driven single
electron in a quantum dot. We find that the pure dephasing of a dressed qubit
due to charge noise can be suppressed substantially at a sweet spot of the
dressed qubit. The relaxation at low magnetic fields exhibits non-monotonic
behavior due to the energy compensation from the driving field. Moreover, the
longitudinal component of the synthetic spin-orbit field could provide fast
electric-dipole-induced dressed-spin resonance (EDDSR). Based on the slow
dephasing and fast EDDSR, we further propose a scheme for dressed-spin-based
semiconductor quantum computing.",2103.05817v1
2022-08-25,Spin mixing conductance and spin magnetoresistance of iridate/manganite interface,"We present results on experimental studies of spin current, measured under
spin pumping at ferromag-netic resonance in wide frequency band 2-20 GHz for
SrIrO3/La0.7Sr0.3MnO3 heterostructures fabricated by RF magnetron sputtering at
high temperature. The epitaxial growth of the thin film in heterostructure by a
cube-on-cube mechanism was confirmed by XRD and TEM analysis. Taking into
account the con-tribution of anisotropic magnetoresistance the spin current was
estimated as 1/3 of the total response. We show that both real and imaginary
parts of spin mixing conductance are valuable for heterostructures with strong
spin-orbit interaction in SrIrO3. Imaginary part of spin mixing conductance was
estimated by means of shift of ferromagnetic resonance field of La0.7Sr0.3MnO3
layer in heterostructure. The spin mag-netoresistance was evaluated from
angular dependencies of magnetoresistance measured in planar Hall
configuration. In order to extract the influence of anisotropic
magnetoresistance a La0.7Sr0.3MnO3 film was measured as well. The spin Hall
angle for heterostructure was found higher than for interface Pt/
La0.7Sr0.3MnO3.",2208.12163v1
2023-11-02,Controllable single spin evolution at sub-harmonics of electric dipole spin resonance enhanced by four-level Landau-Zener-St{ü}ckelberg-Majorana interference,"Sub-harmonics of electric dipole spin resonance (EDSR) mediated by
Landau-Zener-St{\""u}ckelberg-Majorana (LZSM) tunneling transitions are studied
numerically and analytically in a Zeeman-split four level system with strong
spin-orbit coupling that can be realized, for example, in a GaAs-based double
quantum dot in a single-hole regime. The spin qubit is formed in one of the
dots and the second dot is used as an auxiliary element to enhance
functionality of the spin qubit. In particular, it is found that the spin
rotation rate can be essentially enhanced due to the tunnel coupling with the
auxiliary dot on both the main EDSR frequency and at its high sub-harmonics
allowing the coherent spin $\pi$-rotations on a 10-ns time scale. Spin
manipulation on high sub-harmonics is promising for new time-efficient schemes
of the spin control and readout in qubit devices operating at high magnetic
fields where the main harmonic is inaccessible due to hardware limitations.",2311.01607v1
2004-11-07,"Search for optimal 2D and 3D wave launching configurations for the largest acceleration of charged particles in a magnetized plasma, Resonant Moments Method","Optimal two-dimensional (2D), three-dimensional (3D) wave launching
configurations are proposed for enhanced acceleration of charged particles in
magnetized plasmas. A primary wave is launched obliquely with respect to the
magnetic field and a secondary, low amplitude, wave is launched
perpendicularly. The effect of both the launching angle of the primary wave,
and the presence of the secondary wave is investigated. Theoretical predictions
of the highest performances of the three-dimensional (3D) configurations are
proposed using a Resonance Moments Method (RMM) based on estimates for the
moments of the velocity distribution function calculated inside the resonance
layers (RL). They suggest the existence of an optimal angle corresponding to
non parallel launching. Direct statistical simulations show that it is possible
to rise the mean electron velocity up to the order of magnitude as compared to
the primary wave launching alone. It is a quite promising result because the
amplitude of the secondary wave is ten times lower the one of the first wave.
The parameters used are related to magnetic plasma fusion experiments in
electron cyclotron resonance heating and electron acceleration in planetary
ionospheres and magnetospheres.",0411075v4
2007-07-19,Characterization of thermalized Fermi-Pasta-Ulam chains,"The Fermi-Pasta-Ulam (FPU) chains of particles in \textit{thermal
equilibrium} are studied from both wave-interaction and particle-interaction
points of view. It is shown that, even in a strongly nonlinear regime, the
chain in thermal equilibrium can be effectively described by a system of weakly
interacting \textit{renormalized} nonlinear waves. These waves possess (i) the
Rayleigh-Jeans distribution and (ii) zero correlations between waves, just as
noninteracting free waves would. This renormalization is achieved through a set
of canonical transformations. The renormalized linear dispersion of these
renormalized waves is obtained and shown to be in excellent agreement with
numerical experiments. Moreover, a dynamical interpretation of the
renormalization of the dispersion relation is provided via a self-consistency,
mean-field argument. It turns out that this renormalization arises mainly from
the trivial resonant wave interactions, i.e., interactions with no momentum
exchange. Furthermore, using a multiple time-scale, statistical averaging
method, we show that the interactions of near-resonant waves give rise to the
broadening of the resonance peaks in the frequency spectrum of renormalized
modes. The theoretical prediction for the resonance width for the thermalized
$\beta$-FPU chain is found to be in very good agreement with its numerically
measured value. Moreover, we show that the dynamical scenario for thermalized
$\beta$-FPU chains is spatially highly localized discrete breathers riding
chaotically on spatially extended, renormalized waves. We present numerical
evidence of existence of discrete breathers in thermal equilibrium.",0707.2830v1
2007-10-11,"Super-Reflection in Fluid Discs: Corotation Amplifier, Corotation Resonance, Rossby Waves, and Overstable Modes","In differentially rotating discs with no self-gravity, density waves cannot
propagate around the corotation, where the wave pattern rotation speed equals
the fluid rotation rate. Waves incident upon the corotation barrier may be
super-reflected (commonly referred to as corotation amplifier), but the
reflection can be strongly affected by wave absorptions at the corotation
resonance/singularity. The sign of the absorption is related to the Rossby wave
zone very near the corotation radius. We derive the explicit expressions for
the complex reflection and transmission coefficients, taking into account wave
absorption at the corotation resonance. We show that for generic discs, this
absorption plays a much more important role than wave transmission across the
corotation barrier. Depending on the sign of the gradient of the specific
vorticity of the disc the corotation resonance can either enhance or diminish
the super-reflectivity, and this can be understood in terms of the location of
the Rossby wave zone relative to the corotation radius. Our results provide the
explicit conditions (in terms of disc thickness, rotation profile and specific
vorticity gradient) for which super-reflection can be achieved. Global
overstable disc modes may be possible for discs with super-reflection at the
corotation barrier.",0710.2313v3
2020-02-09,Modified Stokes drift due to surface waves and corrugated sea-floor interactions with and without a mean current,"In this paper, we show that Stokes drift may be significantly affected when
an incident intermediate or shallow water surface wave travels over a
corrugated sea-floor. The underlying mechanism is Bragg resonance -- reflected
waves generated via nonlinear resonant interactions between an incident wave
and a rippled bottom. We theoretically explain the fundamental effect of two
counter-propagating Stokes waves on Stokes drift and then perform numerical
simulations of Bragg resonance using High-order Spectral method. A
monochromatic incident wave on interaction with a patch of bottom ripple yields
a complex interference between the incident and reflected waves. When the
velocity induced by the reflected waves exceeds that of the incident, particle
trajectories reverse, leading to a backward drift. Lagrangian and
Lagrangian-mean trajectories reveal that surface particles near the up-wave
side of the patch are either trapped or reflected, implying that the rippled
patch acts as a non-surface-invasive particle trap or reflector. On increasing
the length and amplitude of the rippled patch; reflection, and thus the
effectiveness of the patch, increases. The inclusion of realistic constant
current shows noticeable differences between Lagrangian-mean trajectories with
and without the rippled patch. Theoretical analysis reveals additional terms in
the Stokes drift arising from the particular solution due to
mean-current--bottom-ripple interactions, irrespective of whether Bragg
resonance condition is met. Our analyses may be useful for designing
artificial, corrugated sea-floor patches for mitigating microplastics and other
forms of ocean pollution. We also expect that sea-floor corrugations,
especially in the nearshore region, may significantly affect oceanic tracer
transport.",2002.03434v3
2007-03-19,Resonant energy conversion of 3-minute intensity oscillations into Alfven waves in the solar atmosphere,"Nonlinear coupling between 3-minute oscillations and Alfven waves in the
solar lower atmosphere is studied. 3-minute oscillations are considered as
acoustic waves trapped in a chromospheric cavity and oscillating along
transversally inhomogeneous vertical magnetic field. It is shown that under the
action of the oscillations the temporal dynamics of Alfven waves is governed by
Mathieu equation. Consequently, the harmonics of Alfven waves with twice period
and wavelength of 3-minute oscillations grow exponentially in time near the
layer where the sound and Alfven speeds equal. Thus the 3-minute oscillations
are resonantly absorbed by pure Alfven waves near this resonant layer. The
resonant Alfven waves may penetrate into the solar corona taking energy from
the chromosphere. Therefore the layer c_s=v_A may play a role of energy channel
for otherwise trapped acoustic oscillations.",0703482v1
2002-07-09,Tollmien-Shlichting and sound waves interaction: general description and nonlinear resonances,"The general hydro-thermodynamic system of equations in 2+1 dimensions with
arbitrary equations of state (Taylor series approximation) is split to eigen
modes: Tollmienn-Schlichting (TS) wave and two acoustic ones. A mode definition
is realized via local relation equations, extracted from the linearization of
the general system over boundary layer flow. Each such connection defines the
subspace and the corresponding projector. So the division is performed locally
and could help in initial (or boundary) problems formulation. The general
nonlinearity account determines the specific form of interaction between
acoustic and vortical boundary layer perturbation fields. After the next
projecting to a subspace of Orr-Sommerfeld equation solution for the TS wave
and the corresponding procedure for acoustics, the equations go to
one-dimensional system that describes evolution along the basic stream. A new
mechanism of nonlinear resonance excitation of the TS wave by sound is proposed
and modelled via four-wave interaction. Subjectclass: Primary 35Q30 ; Secondary
76F70, 35Q72; Keywords: keywords fluid mechanics, boundary layer, projector to
eigen modes, Tollmien-Schlichting waves, acoustic waves, nonlinear resonance,
N-wave system.",0207036v1
2019-10-27,Small mass nanopteron traveling waves in mass-in-mass lattices with cubic FPUT potential,"The mass-in-mass (MiM) lattice consists of an infinite chain of identical
beads that are both nonlinearly coupled to their nearest neighbors and linearly
coupled to a distinct resonator particle; it serves as a prototypical model of
wave propagation in granular crystals and metamaterials. We study traveling
waves in an MiM lattice whose bead interaction is governed by the cubic
Fermi-Pasta-Ulam-Tsingou potential and whose resonator mass is small compared
to the bead mass. Excluding a countable number of ""antiresonance"" resonator
masses accumulating at 0, we prove the existence of nanopteron traveling waves
in this small mass limit. The profiles of these waves consist of the
superposition of an exponentially localized core and a small amplitude periodic
oscillation that itself is a traveling wave profile for the lattice. Our
arguments use functional analytic techniques originally developed by Beale for
a capillary-gravity water wave problem and recently employed in a number of
related nanopteron constructions in diatomic Fermi-Pasta-Ulam-Tsingou lattices.",1910.12313v1
2022-06-11,Resonant energization of particles by radio AGN,"A new mechanism of particle acceleration, based on the resonant interaction
of a classical electromagnetic wave (EM) with a quantum wave (associated with a
relativistic particle), is explored.
  In a model illustrative calculation, we study the fate of a Klein Gordon wave
subjected to the intense radio frequency waves generated in the vicinity of an
active galactic nuclei (AGN). In the framework of the paper we examine a
quantum wave associated with a relativistic particle, and it is shown that the
group velocity of the wave approaches the speed of light, implying that the
particles resonantly exchange energy with EM waves, eventually leading to
acceleration of particles to very high energies.
  For typical parameters of under accreting Eddington radio AGN, it is shown
that the resonant energization could catapult particles to extreme energies
$\sim 10^{16-20}$eV.",2206.05429v1
2023-01-01,Whitham Shocks and Resonant Dispersive Shock Waves Governed by the Higher Order Korteweg-de Vries Equation,"The addition of higher order asymptotic corrections to the Korteweg-de Vries
equation results in the extended Korteweg-de Vries equation. These higher order
terms destabilise the dispersive shock wave solution, also termed an undular
bore in fluid dynamics, and result in the emission of resonant radiation. In
broad terms, there are three possible dispersive shock wave regimes: radiating
dispersive shock wave (RDSW), cross-over dispersive shock wave (CDSW) and
travelling dispersive shock wave (TDSW). While there are existing solutions for
the RDSW and TDSW regimes obtained using modulation theory, there is no
existing solution for the CDSW regime. Modulation theory and the associated
concept of a Whitham shock are used to obtain this CDSW solution. In addition,
it is found that the resonant wavetrain emitted by the extended Korteweg-de
Vries equation with water wave coefficients has a minimal amplitude. This
minimal amplitude is explained based on the developed Whitham modulation
theory.",2301.00412v1
2023-10-09,Radio pulsars resonantly accelerating electrons,"Based on the recently demonstrated resonant wave-wave process, it is shown
that electrons can be accelerated to ultra-relativistic energies in the
magnetospheres of radio pulsars. The energization occurs via the resonant
interaction of the electron wave (described by a Klein-Gordon (KG) equation)
moving in unison with an intense electromagnetic (EM) wave; the KG
wave/particle continuously draws energy from EM. In a brief recapitulation of
the general theory, the high energy (resonantly enhanced) electron states are
investigated by solving the KG equation, minimally coupled to the EM field. The
restricted class of solutions, that propagate in phase with EM radiation
(functions only of $\zeta=\omega t-kz$), are explored to serve as a possible
basis for the proposed electron energization in the radio pulsars. We show that
the wave-wave resonant energization mechanism could be operative in a broad
class of radio pulsars with periods ranging from milliseconds to the normal
values ($\sim 1$ sec); it could drive the magnetospheric electrons to acquire
energies from $100$s of TeVs (millisecond pulsars) to $10$ ZeVs (normal
pulsars).",2310.05830v1
2023-10-23,Resonant Scattering of Gravitational Waves With Electromagnetic Waves,"A certain class of exact solutions of Einstein Maxwell spacetime in general
relativity is discussed which demonstrates at the level of theory that, when
certain parametric resonance condition is met, the interaction of
electromagnetic field with a gravitational wave will display certain Liapounov
instability and lead to exponential amplification of a gravitational wave train
described by certain Newman-Penrose component of the Weyl curvature. In some
way akin to a free electron laser in electromagnetic theory, by the conversion
of electromagnetic energy into gravitational energy in a coherent way, the
feasibility of generating a pulsed laser like intense beam of gravitational
wave is displayed.",2310.14920v1
2003-08-04,Modes of wave-chaotic dielectric resonators,"Dielectric optical micro-resonators and micro-lasers represent a realization
of a wave-chaotic system, where the lack of symmetry in the resonator shape
leads to non-integrable ray dynamics. Modes of such resonators display a rich
spatial structure, and cannot be classified through mode indices which would
require additional constants of motion in the ray dynamics. Understanding and
controlling the emission properties of such resonators requires the
investigation of the correspondence between classical phase space structures of
the ray motion inside the resonator and resonant solutions of the wave
equations. We first discuss the breakdown of the conventional eikonal
approximation in the short wavelength limit, and motivate the use of
phase-space ray tracing and phase space distributions. Next, we introduce an
efficient numerical method to calculate the quasi-bound modes of dielectric
resonators, which requires only two diagonalizations per N states, where N is
approximately equal to the number of half-wavelengths along the perimeter. The
relationship between classical phase space structures and modes is displayed
via the Husimi projection technique. Observables related to the emission
pattern of the resonator are calculated with high efficiency.",0308016v1
2009-07-15,Mean shear flows generated by nonlinear resonant Alfven waves,"In the context of resonant absorption, nonlinearity has two different
manifestations. The first is the reduction in amplitude of perturbations around
the resonant point (wave energy absorption). The second is the generation of
mean shear flows outside the dissipative layer surrounding the resonant point.
Ruderman et al. [Phys. Plasmas 4, 75 (1997)] studied both these effects at the
slow resonance in isotropic plasmas. Clack et al. [Astron. Astrophys. 494}, 317
(2009)] investigated nonlinearity at the Alfven resonance, however, they did
not include the generation of mean shear flow. In this present paper, we
investigate the mean shear flow, analytically, and study its properties. We
find that the flow generated is parallel to the magnetic surfaces and has a
characteristic velocity proportional to $\epsilon^{1/2}$, where $\epsilon$ is
the dimensionless amplitude of perturbations far away from the resonance. This
is, qualitatively, similar to the flow generated at the slow resonance. The
jumps in the derivatives of the parallel and perpendicular components of mean
shear flow across the dissipative layer are derived. We estimate the generated
mean shear flow to be of the order of $10{\rm kms}^{-1}$ in both the solar
upper chromosphere and solar corona, however, this value strongly depends on
the choice of boundary conditions. It is proposed that the generated mean shear
flow can produce a Kelvin--Helmholtz instability at the dissipative layer which
can create turbulent motions. This instability would be an additional effect,
as a Kelvin--Helmholtz instability may already exist due to the velocity field
of the resonant Alfven waves. This flow can also be superimposed onto existing
large scale motions in the solar upper atmosphere.",0907.2624v1
2020-04-03,Resonant effect at the ultrarelativistic electron-positron pairs production by gamma quanta in the field of a nucleus and a pulsed light wave,"Resonant electron-positron pair production by a high-energy gamma quantum in
the field of a nucleus and a quasi-monochromatic laser wave was theoretically
studied. Under the resonant condition an intermediate virtual electron
(positron) in the laser field becomes a real particle. Due to that fact the
initial process of the second order in the fine structure constant in a laser
field effectively reduces into two successive processes of the first order: the
laser-stimulated Breit-Wheeler process and the laser-assisted process of an
intermediate electron (positron) scattering by a nucleus. It is shown that
there is a threshold energy for the initial gamma quantum, which significantly
depends on the number of absorbed photons of a wave. In the resonant condition
the electron-positron pair energy is determined by the outgoing angle of a
positron (for the channel A) or an electron (for the channel B) relative to the
initial gamma quantum momentum. The differential cross sections for the first
few resonances with simultaneous registration of the energy and the outgoing
angle of a positron or an electron were obtained. For the initial gamma quantum
energy ${\omega_i} = 125\;{\rm{GeV}}$ the resonant energies of an
electron-positron pair for the case of first three resonances can be measured
with a very high magnitude of the differential cross section: from $ \sim
{10^{13}}$ for the first resonance to $ \sim {10^8}$ (in the units of $\alpha
{Z^2}r_e^2$) for the third resonance.",2004.01530v1
2021-03-09,Classification of resonances and pairing effects on $NA$-scattering within the HFB framework,"We analyze the properties of the scattering solutions obtained as the pole of
the S- and K-matrix with the help of the Jost function framework and the
Strum-Liouville theory within the Hartree-Fock-Bogoliubov(HFB) framework, and
clarify the scattering solutions which can be defined as the physical state. We
found that there are three types of the resonances; ""{\it shape resonance}"",
""{\it particle-type}"" and ""{\it hole-type quasiparticle resonances}"", and
another two types of solutions are given as the independent S-matrix and
K-matrix poles. The shape resonance is formed by the Hartree-Fock(HF) mean
field potential, is not affected by the pairing correlation so much. The
particle-type and hole-type quasiparticle resonances originate from the
particle and hole states by the configuration mixing effect by pairing. All of
resonance are represented by the S-matrix pole which has the corresponding
K-matrix pole. Two other types of solutions are given by the independent
S-matrix and K-matrix poles. These poles are formed by the HF mean field
potential. The effect of pairing for the independent S-matrix pole is small,
but the one for the independent K-matrix pole has the remarkable effect. The
independent K-matrix pole destroys the quasiparticle resonance as it approaches
to the resonance by the pairing effect. The wave function of all resonances
have the characteristic structure of the metastable property. However, the
metastable structure of the wave function of the quasiparticle resonance can be
broken by the independent standing wave solution or the Fano effect.",2103.05181v1
2005-05-27,Second order perturbation theory for spin-orbit resonances,"We implement Lie transform perturbation theory to second order for the planar
spin-orbit problem. The perturbation parameter is the asphericity of the body,
with the orbital eccentricity entering as an additional parameter. We study
first and second order resonances for different values of these parameters. For
nearly spherical bodies like Mercury and the Moon first order perturbation
theory is adequate, whereas for highly aspherical bodies like Hyperion the spin
is mostly chaotic and perturbation theory is of limited use. However, in
between, we identify a parameter range where second order perturbation theory
is useful and where as yet unidentified objects may be in second order
resonances.",0505559v1
1997-10-29,Magnetic Resonance in the Spin-Peierls compound $α'-NaV_2O_5$,"We present results from magnetic resonance measurements for 75-350 GHz in
$\alpha$'-NaV$_{2}$O$_{5}$. The temperature dependence of the integrated
intensity indicates that we observe transitions in the excited state. A
quantitative description gives resonances in the triplet state at high symmetry
points of the excitation spectrum of this Spin-Peierls compound. This energy
has the same temperature dependence as the Spin-Peierls gap. Similarities and
differences with the other inorganic compound CuGeO$_{3}$ are discussed.",9710318v1
1999-03-15,Resonant Raman scattering of quantum wire in strong magnetic field,"The resonant Raman scattering of a quantum wire in a strong magnetic field is
studied, focused on the effect of long range Coulomb interaction and the
spin-charge separation. The energy-momentum dispersions of charge and spin
excitation obtained from Raman cross-section show the characteristc cross-over
behaviour induced by inter-edge Coulomb interaction. The ""SPE"" peak near
resonance in polarized spectra becomes broad due to the momentum dependence of
charge velocity. The broad peak in the depolarized spectra is shown to
originate from the disparity between charge and spin excitation velocity.",9903225v1
1999-07-30,A Modified Approach to Single-Spin Detection Using Magnetic Resonance Force Microscopy,"The magnetic moment of a single spin interacting with a cantilever in
magnetic resonance force microscopy (MRFM) experiences quantum jumps in
orientation rather than smooth oscillations. These jumps cannot be detected by
a conventional MRFM based on observation of driven resonant oscillations of a
cantilever. In this paper, we propose a method which will allow detection of
the magnetic signal from a single spin using a modification of a conventional
MRFM. We estimate the opportunity to detect the magnetic signal from a single
proton.",9907495v1
2001-01-25,Semiclassical quantization and resonance in spin tunnelling,"We derive a semiclassical quantization for a spin, study it for not too small
a spin quantum number (S>5), and compute the 2S+1 eigenvalues of a Hamiltonian
exhibiting resonant tunnelling as the magnetic field parallel to the anisotropy
axis is increased. Special attention is paid to the resonance condition. As a
corollary we prove that semiclassical quantization and quantum-mechanical
perturbation theory agree there where they should.",0101388v1
2002-11-05,Magnetic fluctuations and resonant peak in cuprates: a microscopic theory,"The theory for the dynamical spin susceptibility within the t-J model is
developed, as relevant for the resonant magnetic peak and normal-state magnetic
response in superconducting (SC) cuprates. The analysis is based on the
equations of motion for spins and the memory-function presentation of magnetic
response where the main damping of the low-energy spin collective mode comes
from the decay into fermionic degrees of freedom. It is shown that the damping
function at low doping is closely related to the c-axis optical conductivity.
The analysis reproduces doping-dependent features of the resonant magnetic
scattering.",0211090v1
2003-07-21,Nuclear Magnetic Resonance in a Ferromagnet-Semiconductor Heterostructure,"We report the observation of nuclear magnetic resonance (NMR) in a
ferromagnet-semiconductor heterostructure in the presence of a spin-polarized
current. Spin-polarized electrons injected from a metallic ferromagnet generate
a large nuclear spin population in a GaAs quantum well by dynamic polarization.
The characteristic time for the polarization process is approximately 20 sec,
and the nuclear polarization can persist for several minutes after the current
is turned off. Resonant depolarization is observed in the presence of an AC
magnetic field or when the injection current is modulated at the NMR frequency.",0307512v1
2006-09-19,The emergence of Resonating Valence Bond physics in spin-orbital models,"We discuss how orbital degeneracy, which is usually removed by a cooperative
Jahn-Teller distortion, could under appropriate circumstances lead rather to a
Resonating Valence Bond spin-orbital liquid. The key points are: i) The
tendency to form spin-orbital dimers, a tendency already identified in several
cases; ii) The mapping onto Quantum Dimer Models, which have been shown to
possess Resonating Valence Bond phases on the triangular lattice. How this
program can be implemented is explained in some details starting from a
microscopic model of LiNiO$_2$.",0609455v1
2007-09-22,Multiphoton Bloch-Siegert shifts and level-splittings in spin-one systems,"We consider a spin-boson model in which a spin 1 system is coupled to an
oscillator. A unitary transformation is applied which allows a separation of
terms responsible for the Bloch-Siegert shift, and terms responsible for the
level splittings at anticrossings associated with Bloch-Siegert resonances.
When the oscillator is highly excited, the system can maintain resonance for
sequential multiphoton transitions. At lower levels of excitation, resonance
cannot be maintained because energy exchange with the oscillator changes the
level shift. An estimate for the critical excitation level of the oscillator is
developed.",0709.3557v1
2007-10-12,Coherent Spin Manipulations of a Polarized Beam With a Localized RF Magnetic Field,"The coherent manipulation of spin observables in storage rings provides
opportunities to test the application of some fundamental dynamical principles.
In this context, it is possible to confirm, using gauge invariance and Lorentz
invariance, a conjecture framed by A. M. Kondratenko concerning the ""natural""
or ""intrinsic"" resonance strength applicable to a spin rotation from a
controlled Froissart-Stora sweep with an RF dipole magnet. The discussion
includes a brief treatment of the ""forced"" component of the resonance strength
associated with the effect of the betatron oscillations induced by the
operation of the RF diple and a discussion of the effective resonance strength
as a function of betatron tunes.",0710.2566v1
2008-06-30,Spin Collective Modes of Two-Species Fermi Liquids: Helium-3 and Atomic Gases near the Feshbach Resonance,"We present theoretical findings on the spin collective modes of a two-species
Fermi liquid, prepared alternatively in a polarized equilibrium or a polarized
non-equilibrium state. We explore the effects on these modes of a diverging
s-wave scattering length, as occurs near a Feshbach resonance in a Fermionic
atomic gas. We compare these atomic gas modes with those of the conventional
Helium-3 system, and we find that they differ from the conventional systems,
and that the gap and spin stiffness are tunable via the Feshbach resonance.",0807.0018v1
2010-03-23,Electron Paramagnetic Resonance of Boron Acceptors in Isotopically Purified Silicon,"The electron paramagnetic resonance (EPR) linewidths of B acceptors in Si are
found to reduce dramatically in isotopically purified 28Si single crystals.
Moreover, extremely narrow substructures in the EPR spectra are visible
corresponding to either an enhancement or a reduction of the absorbed microwave
on resonance. The origin of the substructures is attributed to a combination of
simultaneous double excitation and spin relaxation in the four level spin
system of the acceptors. A spin population model is developed which
qualitatively describes the experimental results.",1003.4339v1
2010-12-10,Spin-orbit driven ferromagnetic resonance: A nanoscale magnetic characterisation technique,"We demonstrate a scalable new ferromagnetic resonance (FMR) technique based
on the spin-orbit interaction. An alternating current drives FMR in uniform
ferromagnetic structures patterned from the dilute magnetic semiconductors
(Ga,Mn)As and (Ga,Mn)(As,P). This allows the direct measurement of magnetic
anisotropy coefficients and damping parameters for individual nano-bars. By
analysing the ferromagnetic resonance lineshape, we perform vector magnetometry
on the current-induced driving field, observing contributions with symmetries
of both the Dresselhaus and Rashba spin-orbit interactions.",1012.2397v1
2011-01-05,Effects of La non-magnetic impurities on the spin resonance of CeCoIn$_{5}$,"The influence of La non magnetic impurities on the spin dynamics of
CeCoIn$_{5}$ was studied by inelastic neutron scattering. In La-substituted
systems, the spin resonance peak (observed at $\Omega_{res}=0.55 meV$ in the
pure system) is shifted to lower energies but the ratio
$\Omega_{res}/k_{B}T_{c}$ remains unchanged. The excitation broadens till it
reaches 0.3 meV equal to the value of the quasi-elastic signal in the normal
state. The evolution of La substitution is compared with the evolution of the
magnetic resonance in Ni and Zn substituted YBa$_{2}$Cu$_{3}$O$_{7}$.",1101.1018v1
2011-03-24,Effect of nonadiabatic spin transfer torque on domain wall resonance frequency and mass,"The dynamics of a magnetic domain wall in a semi circular nanowire loop is
studied by an analytical model and micromagnetic simulations. We find a damped
sinusoidal oscillation of the domain wall for small displacement angles around
its equilibrium position under an external magnetic field in the absence of
currents. By studying the effect of current induced nonadiabatic spin transfer
torque on the magnetic domain wall resonance frequency and mass, a red shift is
found in the resonance frequency and domain wall mass increases by increasing
the ratio of nonadiabatic spin torque to adiabatic contribution above 1.",1103.4670v1
2012-03-09,Magnetic field splitting of the spin-resonance in CeCoIn5,"Neutron scattering in strong magnetic fields is used to show the
spin-resonance in superconducting CeCoIn5 (Tc=2.3 K) is a doublet. The
underdamped resonance (\hbar \Gamma=0.069 \pm 0.019 meV) Zeeman splits into two
modes at E_{\pm}=\hbar \Omega_{0}\pm g\mu_{B} \mu_{0}H with g=0.96 \pm 0.05. A
linear extrapolation of the lower peak reaches zero energy at 11.2 \pm 0.5 T,
near the critical field for the incommensurate ""Q-phase"" indicating that the
Q-phase is a bose condensate of spin excitons.",1203.2189v1
2013-06-08,A Raman-induced Feshbach resonance in an effectively single-component Fermi gas,"Ultracold gases of interacting spin-orbit coupled fermions are predicted to
display exotic phenomena such as topological superfluidity and its associated
Majorana fermions. Here, we experimentally demonstrate a route to
strongly-interacting single-component atomic Fermi gases by combining an s-wave
Feshbach resonance (giving strong interactions) and spin-orbit coupling
(creating an effective p-wave channel). We identify the Feshbach resonance by
its associated atomic loss feature and show that, in agreement with our
single-channel scattering model, this feature is preserved and shifted as a
function of the spin-orbit coupling parameters.",1306.1965v1
2013-12-13,Extreme Harmonic Generation in Electrically Driven Spin Resonance,"We report the observation of multiple harmonic generation in electric dipole
spin resonance in an InAs nanowire double quantum dot. The harmonics display a
remarkable detuning dependence: near the interdot charge transition as many as
eight harmonics are observed, while at large detunings we only observe the
fundamental spin resonance condition. The detuning dependence indicates that
the observed harmonics may be due to Landau-Zener transition dynamics at
anticrossings in the energy level spectrum.",1312.3875v2
2015-02-17,Direct Observation of Ferromagnetic State in Gold Nanorods Probed using Electron Spin Resonance Spectroscopy,"X-band electron spin resonance (ESR) spectroscopy has been performed for gold
nanorods (AuNRs) of four different sizes covered with a diamagnetic stabilizing
component, cetyltrimethylammmonium bromide. The ESR spectra show ferromagnetic
features such as hysteresis and resonance field shift, depending on the size of
the AuNRs. In addition, the ferromagnetic transition is indicated by an abrupt
change in the spectra of the two smallest AuNRs studied. A large g-value in the
paramagnetic region suggests that the ferromagnetism in the AuNRs originates
from strong spin-orbit interaction.",1502.04934v1
2018-03-18,Effect of gap anisotropy on the spin resonance peak in the superconducting state of iron-based materials,"Spin resonance in the superconducting state of Fe-based materials within the
multiorbital model with unequal anisotropic gaps on different Fermi surface
sheets is studied. On the basis of the model gap function and the one
calculated within the spin fluctuation theory of pairing, I show that the
resonance peak shifts to higher frequencies with increasing the zero-amplitude
gap magnitude. On the contrary, with increasing the gap anisotropy, it shifts
to lower frequencies and lose some intensity.",1803.06736v2
2018-02-13,Loop-gap Microwave Resonator for Hybrid Quantum Systems,"We designed a loop-gap microwave resonator for applications of spin-based
hybrid quantum systems, and tested it with impurity spins in diamond. Strong
coupling with ensembles of nitrogen-vacancy (NV) centers and substitutional
nitrogen (P1) centers was observed. These results show that loop-gap resonators
are viable in the prospect of spin-based hybrid quantum systems, especially for
an ensemble quantum memory or a quantum transducer.",1802.04485v2
2020-08-22,Pseudospin resonances reveal synthetic spin-orbit interaction,"We investigate a spin-full double quantum dot (DQD) coupled to the leads in a
pseudospin valve configuration. The interplay of interaction and interference
produces in the stability diagram a rich variety of resonances, modulated by
the system parameters. In presence of ferromagnetic leads and pseudospin
anisotropy, those resonances split, turn into dips and acquire a Fano shape
thus revealing a synthetic spin-orbit coupling induced on the DQD. A set of
rate equations derived for a minimal model captures those features. The model
accurately matches the numerical results obtained for the full system in the
framework of a generalized master equation and calculated within the
cotunneling approximation.",2008.09857v1
2017-10-24,Cooperative parametric resonance of the spin one half system of the dense atomic gas,"The cooperative resonance for a spin one half system interacting with dc and
ac magnetic field is considered. This interaction in the system collective
regime can result in parametic resonance and rapid excitation of the excited
spin state of the dense atomic gas. The phenomenon is studied using the density
matrix approach. We discuss the implementation of this effect and possible
applications of the quantum amplification by superradiant emission of
radiation.",1710.08877v1
2019-05-10,Bound-State Band Reconstruction and Resonance in Spin-1/2 Bose Gas with 1D Spin-Orbit Coupling,"In this work, we study two-body bound states in two-component Bose gas with a
one-dimensional (1D) spin-orbit coupling (SOC) induced by Raman lasers. The
finite Raman coupling strength generates coupling among three spin channels,
resulting in the reconstruction of three bound-state bands. In addition,
multiple resonances can be induced at finite scattering lengths. By tuning the
interaction in one intra-species channel, one bound-state band can be lifted
and three resonances can be achieved at different center-of-mass momenta, which
can be observable under current experimental conditions in ${}^{87}$Rb atoms.",1905.03979v1
2023-09-29,Properties of charge-exchange giant spin-dipole resonances in medium-heavy closed-shell parent nuclei: a semimicroscopic description,"The semimicroscopic particle-hole dispersive optical model is adapted for a
description of main properties of charge-exchange giant spin-multipole
resonances in medium-heavy closed-shell parent nuclei. The adapted model is
implemented to evaluating the strength functions, transition densities, and
branching ratios of direct one-nucleon decay for charge-exchange giant
spin-dipole resonances in the ^{48}Ca, ^{90}Zr, ^{132}Sn, and ^{208}Pb parent
nuclei. Some of calculation results are compared with available experimental
data.",2309.17173v3
2022-08-02,Completely Spin-Decoupled Geometric Phase of Metasurface,"Metasurfaces have provided unprecedented degree of freedom (DOF) in
manipulating electromagnetic (EM) waves. Geometric phase can be readily
obtained by rotating the meta-atom of metasurfaces. Nevertheless, such
geometric phases are usually spin-coupled, with the same magnitude but opposite
signs for left_ and right_handed circularly polarized (LCP,RCP) waves. To
achieve independent control on LCP and RCP waves, it is crucial to obtain
spin-decoupled geometric phases. In this paper, we propose to obtain completely
spin-decoupled geometric phases by engineering surface current paths on
meta-atoms. Based on the rotational Doppler effect, the rotation manner is
firstly analyzed and it is found that the essence of generating geometric phase
lies in the rotation of surface current paths on meta-atoms. Since the induced
surface currents paths under LCP and RCP waves always start oppositely and are
mirror-symmetrical with each other, it is natural that the geometric phases be
with the same magnitude and opposite signs when the meta-atoms are rotated. To
obtain spin-decoupled geometric phases, the start point of induced surface
current under one spin should be rotated by an angle while that under the other
spin by another different angle. In this way, LCP and RCP waves can acquire
different geometric phase changes and spin-decoupled geometric phase can be
imparted by metasurfaces. Proof-of-principle prototypes were designed,
fabricated and measured. Both the simulation and experiment results verify
spin-decoupled geometric phases. This work provides a robust means of obtaining
spin-dependent geometric phase and will further adds up to the metasurface DOF
in manipulating EM waves.",2208.04143v1
2005-11-29,Effective spin-wave action for ordered Heisenberg antiferromagnets in a magnetic field,"We derive the effective long-wavelength Euclidean action for the
antiferromagnetic spin-waves of ordered quantum antiferromagnets subject to a
uniform magnetic field. We point out that the magnetic field dependence of the
spin-wave dispersion predicted by the usual O(3)-quantum nonlinear sigma model
disagrees with spin-wave theory. We argue that the nonlinear sigma model does
not take into account all relevant spin-wave interactions and derive a modified
effective action for the long-wavelength spin-waves which contains an
additional quartic interaction. At zero temperature the corresponding vertex is
relevant in the renormalization group sense below three dimensions.",0511706v1
2012-07-24,Interplay of superconductivity and spin density wave order in doped graphene,"We study the interplay between superconductivity and spin density wave order
in graphene doped to 3/8 or 5/8 filling (a Van Hove doping). At this doping
level, the system is known to exhibit weak coupling instabilities to both
chiral d + id superconductivity and to a uniaxial spin density wave. Right at
van Hove doping, the superconducting instability is strongest and emerges at
the highest Tc, but slightly away from van-Hove doping a spin-density-wave
likely emerges first. We investigate whether at some lower temperature
superconductivity and spin-density-waves co-exist. We derive the
Landau-Ginzburg functional describing interplay of the two order parameters.
Our calculations show that superconductivity and spin density wave order do not
co-exist and are separated by first-order transitions, either as a function of
doping or as a function of T.",1207.5802v1
2012-11-21,Spin-wave propagation and transformation in a thermal gradient,"The influence of a thermal gradient on the propagation properties of
externally excited dipolar spin waves in a magnetic insulator waveguide is
investigated. It is shown that spin waves propagating towards a colder region
along the magnetization direction continuously reduce their wavelength. The
wavelength increase of a wave propagating into a hotter region was utilized to
realize its decomposition in the partial waveguide modes which are reflected at
different locations. This influence of temperature on spin-wave properties is
mainly caused by a change in the saturation magnetization and yields promising
opportunities for the manipulation of spin waves in spin-caloritronic
applications.",1211.5017v1
2013-05-22,Spin-wave nonreciprocity based on interband magnonic transitions,"We theoretically demonstrate linear spin-wave nonreciprocity in a Ni80Fe20
nanostripe waveguide, based on interband magnonic transitions induced by a
time-reversal and spatialinversion symmetry breaking magnetic field. An
analytical coupled-mode theory of spin waves, developed to describe the
transitions which are accompanied by simultaneous frequency and wavevector
shifts of the coupled spin waves, is well corroborated by numerical
simulations. Our findings could pave the way for the realization of spin-wave
isolation and the dynamic control of spin-wave propagation in nanoscale
magnonic integrated circuits via an applied magnetic field.",1305.5018v3
2015-06-23,Chirality-dependent transmission of spin waves through domain walls,"Spin-wave technology (magnonics) has the potential to further reduce the size
and energy consumption of information processing devices. In the submicrometer
regime (exchange spin waves), topological defects such as domain walls may
constitute active elements to manipulate spin waves and perform logic
operations. We predict that spin waves that pass through a domain wall in an
ultrathin perpendicular-anisotropy film experience a phase shift that depends
on the orientation of the domain wall (chirality). The effect, which is absent
in bulk materials, originates from the interfacial Dzyaloshinskii-Moriya
interaction and can be interpreted as a geometric phase. We demonstrate
analytically and by means of micromagnetic simulations that the phase shift is
strong enough to switch between constructive and destructive interference. The
two chirality states of the domain wall may serve as a memory bit or spin-wave
switch in magnonic devices.",1506.07038v2
2015-07-06,Spin Wave Eigenmodes of Dzyaloshinskii Domain Walls,"A theory for the spin wave eigenmodes of a Dzyaloshinskii domain wall is
presented. These walls are N\'eel-type domain walls that can appear in
perpendicularly-magnetized ultrathin ferromagnets in the presence of a sizeable
Dzyaloshinskii-Moriya interaction. The mode frequencies for spin waves
propagating parallel and perpendicular to the domain wall are computed using a
continuum approximation. In contrast to Bloch-type walls, it is found that the
spin wave potential associated with Dzyaloshinskii domain walls is not
reflectionless, which leads to a finite scattering cross-section for
interactions between spin waves and domain walls. A gap produced by the
Dzyaloshinskii interaction emerges, and consequences for spin wave driven
domain wall motion and band structures arising from periodic wall arrays are
discussed.",1507.01369v1
2015-09-17,A spin wave diode,"A diode, a device allowing unidirectional signal transmission, is a
fundamental element of logic structures and lies in the heart of modern
information systems. Spin wave or magnon, representing a collective
quasi-particle excitation of the magnetic order in magnetic materials, is a
promising candidate of information carrier for the next generation
energy-saving technologies. Here we propose a scalable and reprogrammable pure
spin wave logic hardware architecture using domain walls and surface anisotropy
stripes as waveguides on a single magnetic wafer. We demonstrate theoretically
the design principle of the simplest logic component, a spin wave diode,
utilizing the chiral bound states in a magnetic domain wall with
Dzyaloshiskii-Moriya interaction, and confirm its performance through
micromagnetic simulations. Our findings open a new vista for realizing
different types of pure spin wave logic components and finally achieving an
energy-efficient and hardware-reprogrammable spin wave computer.",1509.05095v1
2016-08-25,"Spin waves in the AF state of the $t$-$t'$ Hubbard model on the fcc lattice: competing interactions, frustration, and instabilities","Spin waves in the type-III ordered antiferromagnetic state of the frustrated
$t$-$t'$ Hubbard model on the fcc lattice are calculated to investigate
finite-$U$-induced competing interaction and frustration effects on magnetic
excitations and instabilities. Particularly strong competing interactions
generated due to interplay of fcc lattice geometry and magnetic order result in
significant spin wave softening. The calculated spin wave dispersion is found
to be in qualitative agreement with the measured spin wave dispersion in the
pyrite mineral $\rm Mn S_2$ obtained from inelastic neutron scattering
experiments. Instabilities to other magnetic orders (type I, type II, spiral,
non-collinear), as signalled by spin wave energies turning negative, are also
discussed.",1608.07031v1
2016-10-22,Giant nonreciprocal emission of spin waves in Ta/Py bilayers,"Spin waves are propagating disturbances in the magnetization of magnetic
materials. One of their interesting properties is the nonreciprocity,
exhibiting that their amplitude depends on the magnetization direction.
Nonreciprocity in spin waves is of great interest in both fundamental science
and applications, as it offers an extra knob to control the flow of waves for
the technological fields of logics and switch applications. We show a high
nonreciprocity in spin waves from Ta/Py bilayer systems with out-of-plane
magnetic fields. The nonreciprocity depends on the thickness of Ta underlayer
which is found to induce an interfacial anisotropy. The origin of observed high
nonreciprocity is twofold; different polarities of the in-plane magnetization
due to different angles of canted out-of-plane anisotropy and the spin pumping
effect at the Ta/Py interface. Our findings provide an opportunity to engineer
highly efficient nonreciprocal spin wave based applications such as
nonreciprocal microwave devices, magnonic logic gates, and information
transports.",1610.07023v1
2017-05-05,Nano-patterned magnonic crystals based on ultrathin YIG films,"We demonstrate a microscopic magnonic-crystal waveguide produced by
nano-patterning of a 20 nm thick film of Yttrium Iron Garnet. By using the
phase-resolved micro-focus Brillouin light scattering spectroscopy, we map the
intensity and the phase of spin waves propagating in such a periodic magnetic
structure. Based on these maps, we obtain the dispersion and the attenuation
characteristics of spin waves providing detailed information about the physics
of spin-wave propagation in the magnonic crystal. We show that, in contrast to
the simplified physical picture, the maximum attenuation of spin waves is
achieved close to the edge of the magnonic band gap, which is associated with
non-trivial reflection characteristics of spin waves in non-uniform field
potentials.",1705.02267v1
2019-02-26,A new class of nonreciprocal spin waves on the edges of 2D antiferromagnetic honeycomb nanoribbons,"Antiferromagnetic two-dimensional (2D) materials are currently under
intensive theoretical and experimental investigations in view of their
potential applications in antiferromagnet-based magnonic and spintronic
devices. Recent experimental studies revealed the importance of magnetic
anisotropy and Dzyaloshinskii-Moriya interactions (DMI) on the ordered ground
state and the magnetic excitations in these materials. Here we present a robust
classical field theory approach to analyze the effect of magnetic anisotropy
and Dzyaloshinskii-Moriya interactions (DMI) on the edge and bulk spin waves in
2D antiferromagnetic nanoribbons. We predict the existence of a new class of
nonreciprocal edge spin waves characterized by opposite polarizations in
opposite directions. These novel edge spin waves are induced by the DMI and are
fundamentally different from conventional nonreciprocal spin waves for which
the polarization is independent of the propagation direction. Aside this
breakthrough in the field of antiferromagnetic spin waves, the study further
analysis the effect of the edges structure on the magnetic excitations. In
particular, we show that anisotropic bearded edges nanoribbons act as magnetic
topological insulators with exceptionally interesting potentials for
applications in magnonics.",1902.09704v3
2020-07-15,Nanochannels for Spin-Wave Manipulation in Ni80Fe20 Nanodot Arrays,"Patterned magnetic nanostructures are potential candidates for future energy
efficient, on-chip communication devices. Here, we have experimentally and
numerically studied the role of nanochannels to manipulate spin waves in
Ni80Fe20 connected nanodot arrays of varying filling fraction. Rich spin-wave
spectra are observed in these samples, where the number of spin-wave modes
decreases with increasing filling fraction due to the retrenchment of the
demagnetizing field. The nanochannels affect the spin-wave modes of the
connected dots through dipole-exchange coupling. For all modes the vertical
nanochannels couple the nanodots, except for the highest frequency modes where
all nanochannels act as coupler. This feature is further explored in the
simulation, which reveals that only the highest frequency mode can propagate
through all the nanochannels, analogues to an electronic demultiplexer. This
study will be useful to understand the role of nanochannels in patterned
magnetic nanostructures and their applications in spin-wave based communication
devices.",2007.07685v1
2021-03-18,Cherenkov radiation of spin waves by ultra-fast moving magnetic flux quanta,"Despite theoretical predictions for a Cherenkov-type radiation of spin waves
(magnons) by various propagating magnetic perturbations, fast-enough moving
magnetic field stimuli have not been available so far. Here, we experimentally
realize the Cherenkov radiation of spin waves in a Co-Fe magnonic conduit by
fast-moving (>1 km/s) magnetic flux quanta (Abrikosov vortices) in an adjacent
Nb-C superconducting strip. The radiation is evidenced by the microwave
detection of spin waves propagating a distance of 2 micrometers from the
superconductor and it is accompanied by a magnon Shapiro step in its
current-voltage curve. The spin-wave excitation is unidirectional and
monochromatic, with sub-40 nm wavelengths determined by the period of the
vortex lattice. The phase-locking of the vortex lattice with the excited spin
wave limits the vortex velocity and reduces the dissipation in the
superconductor.",2103.10156v2
2022-01-21,Eigenmodes of twisted spin-waves in a thick ferromagnetic nanodisk,"Magnetic vortex is topologically nontrivial and commonly found in
ferromagnetic nanodisks. So far, three classes spin-wave eigenmodes, i.e.,
gyrotropic, azimuthal and radial modes, have been identified in ferromagnetic
nanodisks. Here, using micromagnetic simulation and analytical calculation, we
reveal twisted spin-wave modes in a thick permalloy (Ni0.8Fe0.2) nanodisk. The
twisted spin-waves carry topological charges, which sign depends on the core
polarity of the magnetic vortex in the nanodisk. By applying rotating magnetic
fields at one end of the sample, we observe continuous generation of twisted
spin-waves that have characteristic spiral phase front and carry topological
charge l = 1, -1, 2 and -2. The dispersion relation of twisted spin-waves is
derived analytically and the result is in good agreement with micromagnetic
numerical calculations.",2201.08621v1
2022-11-07,Interaction of gapless spin waves and a domain wall in an easy-cone ferromagnet,"We theoretically study the interaction of spin waves and a domain wall in a
quasi-one-dimensional easy-cone ferromagnet. The gapless spin waves on top of a
domain wall are found to exhibit finite reflection in contrast to the
well-known perfect transmission of gapful spin waves in easy-axis magnets.
Based on the obtained scattering properties, we study the thermal-magnon-driven
dynamics of a domain wall subjected to a thermal bias within the
Landau-B\""uttiker formalism, where transmitted magnons are shown to exert the
magnonic torque on the domain wall and thereby drive it with the velocity
linear to the applied thermal bias. The peculiar gapless nature of spin waves
in easy-cone magnets enables the thermally-driven domain-wall motion even at
low temperatures, differing from the easy-axis case where the domain-wall
velocity is exponentially suppressed at low temperatures. Our work suggests
that easy-cone magnets can serve as a useful platform to study the interaction
of gapless spin waves and nonlinear excitations and thereby realize
low-temperature magnon-related phenomena.",2211.03331v1
2023-02-21,Micromagnetic study of inertial spin waves in ferromagnetic nanodots,"Here we report the possibility to excite ultra-short spin waves in
ferromagnetic thin-films by using time-harmonic electromagnetic fields with
terahertz frequency. Such ultra-fast excitation requires to include inertial
effects in the description of magnetization dynamics. In this respect, we
consider the inertial Landau-Lifshitz-Gilbert (iLLG) equation and develop
analytical theory for exchange-dominated inertial spin waves. The theory
predicts a finite limit for inertial spin wave propagation velocity, as well as
spin wave spatial decay and lifetime as function of material parameters. Then,
guided by the theory, we perform numerical micromagnetic simulations that
demonstrate the excitation of ultra-short inertial spin waves (20 nm long)
propagating at finite speed in a confined magnetic nanodot. The results are in
agreement with the theory and provide the order of magnitude of quantities
observable in realistic ultra-fast dynamics experiments.",2302.10759v2
2023-07-19,Zero-field spin waves in YIG nano-waveguides,"Spin-wave based transmission and processing of information is a promising
emerging nano-technology that can help overcome limitations of traditional
electronics based on the transfer of electrical charge. Among the most
important challenges for this technology is the implementation of spin-wave
devices that can operate without the need for an external bias magnetic field.
Here we experimentally demonstrate that this can be achieved using
sub-micrometer wide spin-wave waveguides fabricated from ultrathin films of
low-loss magnetic insulator - Yttrium Iron Garnet (YIG). We show that these
waveguides exhibit a highly stable single-domain static magnetic configuration
at zero field and support long-range propagation of spin waves with gigahertz
frequencies. The experimental results are supported by micromagnetic
simulations, which additionally provide information for optimization of
zero-field guiding structures. Our findings create the basis for the
development of energy-efficient zero-field spin-wave devices and circuits.",2307.09805v1
2023-09-11,Probing Spin Wave Diffraction Patterns of Curved Antennas,"We report on the dependence of curvilinear shaped coplanar waveguides on the
near-field diffraction patterns of spin waves propagating in perpendicularly
magnetized thin films. Implementing the propagating spin waves spectroscopy
techniques on either concentrically or eccentrically shaped antennas, we show
how the link budget is directly affected by the spin wave interference, in good
agreement with near-field diffraction simulations. This work demonstrates the
feasibility to inductively probe a magnon interference pattern with a
resolution down to 1$\mu$m$^2$, and provides a methodology for shaping spin
wave beams from an antenna design. This methodology is successfully implemented
in the case study of a spin wave Young's interference experiment.",2309.05532v1
2023-11-27,Zero-field spin wave turns,"Spin-wave computing, a potential successor to CMOS-based technologies, relies
on the efficient manipulation of spin waves for information processing. While
basic logic devices like magnon transistors, gates, and adders have been
experimentally demonstrated, the challenge for complex magnonic circuits lies
in steering spin waves through sharp turns. In this study we demonstrate with
micromagnetic simulations and Brillouin light scattering microscopy
experiments, that dipolar spin waves can propagate through 90-degree turns
without distortion. The key lies in carefully designed in-plane magnetization
landscapes, addressing challenges posed by anisotropic dispersion. The
experimental realization of the required magnetization landscape is enabled by
spatial manipulation of the uniaxial anisotropy using corrugated magnonic
waveguides. The findings presented in this work should be considered in any
magnonic circuit design dealing with anisotropic dispersion and spin wave
turns.",2311.16335v1
2023-12-13,Detection of Geometric Phases in Spin Waves using Nitrogen-Vacancy Centers,"Due to their robustness, the implementation of geometric phases provides a
reliable and controllable way to manipulate the phase of a spin wave, thereby
paving the way towards functional magnonics-based data processing devices.
Moreover, geometric phases in spin waves are interesting from a fundamental
perspective as they contain information about spin wave band structures and
play an important role in magnon Hall effects. In this paper we propose to
directly measure geometric phases in spin wave systems using the magnetic field
sensing capabilities of nitrogen-vacancy (NV) centers. We demonstrate the
general principles of this method on two systems in which spin waves acquire a
geometric phase, namely a wire with a magnetic domain wall and a system with
position-dependent anisotropy axes, and explicitly show how this phase can be
deduced from the NV center signal.",2312.08137v1
2001-03-28,"Motion, Universality of Velocities, Masses in Wave Universe. Transitive States (Resonances) - Mass Spectrum","Wave Universe Concept (WU Concept) opens new wide possibilities for the
effective description of Elementar Objects of Matter (EOM) hierarchy, in
particular, of particles, resonances mass spectrum of subatomic (and HEP)
physics.
  The special attention to analysis and precise description of wide and
important set - Transitive states (resonances) of EOM is payed.
  Its are obtained sufficiently precise representations for mass values, cross
relations between masses of wide set objects of particle physics - metastable
resonances - (fast moving) Transitive states - in terms of representations of
Wave Universe Concept (WU Concept).
  Wide set of observed in experiments effects and connected with its resonances
(including - Darmstadt effect, ABC effect,etc.) may be effectively interpreted
in WU Concept and described with use of mass formula - as manifestation of
rapidly moving, physically distinguished transitive states (resonances)",0103089v1
2010-06-28,Separation of bacterial spores from flowing water in macro-scale cavities by ultrasonic standing waves,"The separation of micron-sized bacterial spores (Bacillus cereus) from a
steady flow of water through the use of ultrasonic standing waves is
demonstrated. An ultrasonic resonator with cross-section of 0.0254 m x 0.0254 m
has been designed with a flow inlet and outlet for a water stream that ensures
laminar flow conditions into and out of the resonator section of the flow tube.
A 0.01905-m diameter PZT-4, nominal 2-MHz transducer is used to generate
ultrasonic standing waves in the resonator. The acoustic resonator is 0.0356 m
from transducer face to the opposite reflector wall with the acoustic field in
a direction orthogonal to the water flow direction. At fixed frequency
excitation, spores are concentrated at the stable locations of the acoustic
radiation force and trapped in the resonator region. The effect of the
transducer voltage and frequency on the efficiency of spore capture in the
resonator has been investigated. Successful separation of B. cereus spores from
water with typical volume flow rates of 40-250 ml/min has been achieved with
15% efficiency in a single pass at 40 ml/min.",1006.5467v1
2013-02-18,A Dynamical Cross-over Regime in the Transmission and Reflection Spectra of Evanescent Waves with 2D Arrays of Josephson Junctions,"A dynamical cross-over regime is revealed when exposing a classical
two-dimensional ordered Josephson junction (JJ) array to evanescent waves and
tuning the incident microwave power. At the lowest possible temperature for
these experiments, 1.1 K, and at the lowest power setting, -55 dBm, evanescent
waves are transmitted without loss and the resonance exhibits a quality factor
of ~ 4200. A second, smaller resonance, which evolves with increasing power
from the main resonance, is also investigated. In contrast to the behavior of
the main resonance, this second peak grows as the incident power is increased
and does not maintain a fixed resonant frequency for temperatures less than the
superconducting critical temperature of niobium. The tunability of both
resonances is studied as a function of temperature and microwave power. Finally
we speculate that this dynamical crossover regime is evidence of a transition
between two states of phase coherence where at low microwave power the JJ
arrays are phase locked and at high microwave power the JJ arrays are unlocked.",1302.4364v1
2014-04-26,Multichannel quantum-defect theory for magnetic Feshbach resonances in heteronuclear group I systems,"We present a multichannel quantum-defect theory for magnetic Feshbach
resonances in the interaction of two heteronuclear group I atoms. The theory
provides a unified and a uniform description of resonances in all partial
waves, and enables the characterization of large number of resonances in terms
of very few parameters. For the sample system of $^6$Li$^{40}$K, we present
descriptions of all resonances in $aa$, $ab$, and $ba$ channels, in partial
waves $s$ ($l=0$) through $h$ ($l=5$), and in a magnetic field of 0 through
1000 Gauss. All resonances, including those in nonzero partial waves, are fully
characterized using the newly developed parametrization of Gao [Phy. Rev. A
\textbf{84}, 022706 (2011)].",1404.6676v1
2016-08-02,"Tilted resonators in a triangular elastic lattice: chirality, Bloch waves and negative refraction","We consider a vibrating triangular mass-truss lattice whose unit cell
contains a resonator of a triangular shape. The resonators are connected to the
triangular lattice by trusses. Each resonator is tilted, i.e. it is rotated
with respect to the triangular lattice's unit cell through an angle
$\vartheta_0$. This geometrical parameter is responsible for the emergence of a
resonant mode in the Bloch spectrum for elastic waves and strongly affects the
dispersive properties of the lattice. Additionally, the tilting angle
$\vartheta_0$ triggers the opening of a band gap at a Dirac-like point. We
provide a physical interpretation of these phenomena and discuss the dynamical
implications on elastic Bloch waves. The dispersion properties are used to
design a structured interface containing tilted resonators which exhibit
negative refraction and focussing, as in a ""flat elastic lens"".",1608.00968v1
2018-11-08,Quasistatic oscillations in subwavelength particles: Can one observe energy eigenstates?,"In increasing the capabilities of the optical and microwave techniques
further into the subwavelength regime, quasistatic resonant structures has
attracted considerable interest. Electromagnetic responses of electrostatic
(ES) plasmon resonances in optics and magnetostatic (MS) magnon resonances in
microwaves give rise to a strong enhancement of local fields near the surfaces
of subwavelength particles. In the near-field regions of subwavelength
particles one can only measure the electric or the magnetic field with
accuracy. Such uncertainty in definition of the electric or magnetic field
components raises the question of energy eigenstates of quasistatic
oscillations. The energy eigenstate problem can be properly formulated when
potential functions, used in the quasistatic-resonance problems, are introduced
as scalar wave functions. In this case, one should observe quasistatic-wave
retardation effects still staying in frames of the quasistatic description of
oscillations in a subwavelength particle. In this paper, we analyze the problem
of energy quantization of ES resonances in subwavelength optical metallic
structures with plasmon oscillations and MS resonances in subwavelength
microwave ferrite particles with magnon oscillations. We show that in a case of
MS-potential scalar wave function one can observe quasistatic retardation
effects and obtain a proper formulation of the energy eigenstate problem.",1811.03314v1
2008-06-24,Fractional resonances in the atom-optical delta-kicked accelerator,"We consider resonant dynamics in a dilute atomic gas falling under gravity
through a periodically pulsed standing-wave laser field. Our numerical
calculations are based on a Monte Carlo method for an incoherent mixture of
noninteracting plane waves, and show that quantum resonances are highly
sensitive to the relative acceleration between the atomic gas and the pulsed
optical standing wave. For particular values of the atomic acceleration, we
observe fractional resonances. We investigate the effect of the initial atomic
momentum width on the fractional resonances, and quantify the sensitivity of
fractional resonances to thermal effects.",0806.3894v2
2019-08-01,Universal scaling behavior of resonant absorption,"Mode conversion and resonant absorption are crucial mechanisms for wave
transport and absorption. Scaling behavior of mode conversion or resonant
absorption is well-known for electromagnetic and MHD waves in planar geometry.
Our recent study showed that such a scaling behavior of resonant absorption
could also exist for coronal loop oscillations with cylindrical geometry, but
it was only tested for one density profile. Here we generalise our previous
study on the scaling behavior of resonant absorption by considering multiple
density profiles. Applying an invariant imbedding method to the ideal MHD wave
equations, we show that the scaling behavior also exists for these density
models. We thus generalise our earlier results and show that such a universal
scaling exists in cylindrical geometry, too. Given these results and the
earlier results in planar geometry, we formulate a hypothesis that a universal
scaling behavior exists regardless of the type of mode conversion or resonant
absorption.",1908.00214v1
2020-06-26,Surface acoustic wave coupling between micromechanical resonators,"The coupling of micro- or nanomechanical resonators via a shared substrate is
intensively exploited to built systems for fundamental studies and practical
applications. So far, the focus has been on devices operating in the kHz regime
with a spring-like coupling. At resonance frequencies above several 10 MHz,
wave propagation in the solid substrate becomes relevant. The resonators act as
sources for surface acoustic waves (SAWs) and it is unknown how this effects
the coupling between them. Here, we present a model for MHz frequency
resonators interacting by SAWs and derive the eigenfrequencies and quality
factors of a pair of resonators for the symmetric and antisymmetric mode. Our
results are in agreement with finite element method (FEM) simulations and show
that in contrast to the well-known strain-induced spring-like coupling, the
coupling via SAWs is not only dispersive but also dissipative. This can be
exploited to realize high quality phonon cavities, an alternative to acoustic
radiation shielding by, e.g. phononic crystals.",2006.14862v4
2021-07-08,Nonlinear coupling of phononic resonators induced by surface acoustic waves,"The rising need for hybrid physical platforms has triggered a renewed
interest for the development of agile radio-frequency phononic circuits with
complex functionalities. The combination of travelling waves with resonant
mechanical elements appears as an appealing means of harnessing elastic
vibration. In this work, we demonstrate that this combination can be further
enriched by the occurrence of elastic non-linearities induced travelling
surface acoustic waves (SAW) interacting with a pair of otherwise linear
micron-scale mechanical resonators. Reducing the resonator gap distance and
increasing the SAW amplitude results in a frequency softening of the resonator
pair response that lies outside the usual picture of geometrical Duffing
non-linearities. The dynamics of the SAW excitation scheme allows further
control of the resonator motion, notably leading to circular polarization
states. These results paves the way towards versatile high-frequency
phononic-MEMS/NEMS circuits fitting both classical and quantum technologies.",2107.03865v1
2022-05-30,Triadic resonant instability in confined and unconfined axisymmetric geometries,"We present an investigation of the resonance conditions of axisymmetric
internal wave sub-harmonics in confined and unconfined domains. In both cases,
sub-harmonics can be spontaneously generated from a primary wave field if they
satisfy at least a resonance condition on their frequencies, of the form
$\omega_0 = \pm \omega_1 \pm \omega_2$. We demonstrate that, in an unconfined
domain, the sub-harmonics follow three dimensional spatial resonance conditions
similar to the ones of Triadic Resonance Instability (TRI) for Cartesian plane
waves. In a confined domain, however, the spatial structure of the
sub-harmonics is fully determined by the boundary conditions and we observed
that these conditions prevail upon the resonance conditions. In both
configurations, these findings are supported by experimental data showing good
agreement with analytical and numerical derivations.",2205.15179v1
2022-11-11,Wavy optical grating: wideband reflector and Fabry-Perot BICs,"In this study, we theoretically and numerically investigate the resonant
modes and reflectance of an optical grating consisting of a wavy dielectric
slab by applying the spectral element method. The presence of the wavy shape
transforms the waveguide modes into leaky resonant modes. A few resonant modes
with specific longitudinal wave number have infinitely large Q factor, while
the other resonant modes have finite Q factor. For the leaky resonant mode with
zero longitudinal wave number, the Q factor is inversely proportional to the
amplitude of the wavy shape. An array of multiple low-Q wavy gratings has a
high reflectance in a large bandwidth. A double-layer wavy grating forms a
Fabry-Perot cavity, which hosts Fabry-Perot bound states in the continuum
(BICs) at the resonant frequency. The Q-factor of the Fabry-Perot cavity can be
tuned by adjusting the distance between the two wavy slabs. The wavy shape
could be generated by a vibrational wave in a flat dielectric slab so that the
BICs mode and wideband reflectance could be controlled on-demand.",2211.06201v1
2023-03-12,Towards practical mass spectrometry with nanomechanical pillar resonators by surface acoustic wave transduction,"Nanoelectromechanical systems (NEMS) have proven outstanding performance in
the detection of small masses down to single proton sensitivity. To obtain a
high enough throughput for the application in practical mass spectrometry, NEMS
resonators have to be arranged in two-dimensional (2D) arrays. However, all
state-of-the-art electromechanical transduction methods rely on electrical
lines placed close to the mechanical resonators, which drastically restricts
the density of 2D resonator arrays. An exception is the transduction by surface
acoustic waves (SAWs), which has so far only been shown for the transduction of
single nanomechanical pillar resonators. Here, we demonstrate the transduction
of pillar pairs by surface acoustic waves. The pillars have a diameter of 700
nm and show a mass responsivity of -588$\pm$98 ng$^{-1}$. The distances between
the pillar pairs are 70 nm and 14.3 $\mu$m. SAW transduction enabled us to
measure both pillars of each pair with electrical lines no closer than 300
$\mu$m, illustrating the potential of SAWs to transduce dense arrays of pillar
resonators, a crucial step towards practical mass spectrometry with NEMS.",2303.06665v1
2023-06-22,High-impedance surface acoustic wave resonators,"Because of their small size, low loss, and compatibility with magnetic fields
and elevated temperatures, surface acoustic wave resonators hold significant
potential as future quantum interconnects. Here, we design, fabricate, and
characterize GHz-frequency surface acoustic wave resonators with the potential
for strong capacitive coupling to nanoscale solid-state quantum systems,
including semiconductor quantum dots. Strong capacitive coupling to such
systems requires a large characteristic impedance, and the resonators we
fabricate have impedance values above 100 $\Omega$. We achieve such high
impedance values by tightly confining a Gaussian acoustic mode. At the same
time, the resonators also have low loss, with quality factors of several
thousand at millikelvin temperatures. These high-impedance resonators are
expected to exhibit large vacuum electric-field fluctuations and have the
potential for strong coupling to a variety of solid-state quantum systems.",2306.12993v2
2014-05-01,Resonant Scattering of Surface Plasmon Polaritons by Dressed Quantum Dots,"The resonant scattering of surface plasmon-polariton waves by embedded
semiconductor quantum dots above the dielectric/metal interface is explored in
the strong-coupling regime. In contrast to non-resonant scattering by a
localized dielectric surface defect, a strong resonant peak in the scattering
field spectrum is predicted and accompanied by two side valleys. The peak
height depends nonlinearly on the amplitude of surface plasmon-polariton waves,
reflecting the feedback dynamics from a photon-dressed electron-hole plasma
inside the quantum dots. This unique behavior in the scattering field peak
strength is correlated with the occurrence of a resonant dip in the absorption
spectrum of surface plasmon-polariton waves due to interband photon-dressing
effect. Our result on the scattering of surface plasmon-polariton waves may be
experimentally observable and applied to spatially selective illumination and
imaging of individual molecules.",1405.0215v1
2014-05-02,Rotation-induced Mode Coupling in Open Wavelength-scale Microcavities,"We study the interplay between rotation and openness for mode coupling in
wavelength-scale microcavities. In cavities deformed from a circular disk, the
decay rates of a quasi-degenerate pair of resonances may cross or anti-cross
with increasing rotation speed. The standing-wave resonances evolve to
traveling-wave resonances at high rotation speed, however, both the clockwise
(CW) and counter-clockwise (CCW) traveling-wave resonances can have a lower
cavity decay rate, in contrary to the intuitive expectation from
rotation-dependent effective index. With increasing rotation speed, a phase
locking between the CW and CCW wave components in a resonance takes place.
These phenomena result from the rotation-induced mode coupling, which is
strongly influenced by the openness of the microcavity. The possibility of a
non-monotonic Sagnac effect is also discussed.",1405.0468v1
2015-05-14,A Self-Assembled Metamaterial for Lamb Waves,"We report the design and characterization of a self-assembled, locally
resonant acoustic metamaterial for Lamb waves, composed of a monolayer of
$1.02$ $\mu$m polystyrene microspheres adhered to a $1.3$ $\mu$m thick
free-standing silicon membrane. A laser-induced transient grating technique is
used to generate Lamb waves in the metamaterial and measure its acoustic
response. The measurements reveal a microsphere contact resonance and the
lowest frequency spheroidal microsphere resonance. The measured dispersion
curves show hybridization of flexural Lamb waves with the microsphere contact
resonance. We compare the measured dispersion with an analytical model using
the contact resonance frequency as a single fitting parameter, and find that it
well describes the observed hybridization. Results from this study can lead to
an improved understanding of microscale contact mechanics and to the design of
new types of acoustic metamaterials.",1505.03777v2
2016-04-28,Effective medium theory for acoustic waves in bubbly fluids near Minnaert resonant frequency,"We derive an effective medium theory for acoustic wave propagation in bubbly
fluid near Minnaert resonant frequency. We start with a multiple scattering
formulation of the scattering problem of an incident wave by a large number of
identical small bubbles in a homogeneous fluid. Under certain conditions on the
configuration of the bubbles, we justify the point interaction approximation
and establish an effective medium theory for the bubbly fluid as the number of
bubbles tends to infinity. The convergence rate is also derived. As a
consequence, we show that near and below the Minnaert resonant frequency, the
obtained effective media can have a high refractive index, which is the reason
for the super-focusing experiment observed in ""Subwavelength focusing in bubbly
media using broadband time reversal"", Physical Review, B (2015), by M. Lanoy et
al. Moreover, our results indicate that the obtained effective medium can be
dissipative above the Minnaert resonant frequency, while at that frequency,
effective medium theory does not hold. Our theory sheds light on the mechanism
of the extraordinary wave properties of metamaterials, which include bubbly
fluid as an example, near resonant frequencies.",1604.08409v1
2017-07-02,Research on the halo in $^{31}$Ne with complex momentum representation method,"Halo is one of the most interesting phenomena in exotic nuclei especially for
$^{31}$Ne, which is deemed to be a halo nucleus formed by a $p-$wave resonance.
However, the theoretical calculations don't suggest a $p-$wave resonance using
the scattering phase shift approach or complex scaling method. Here, we apply
the complex momentum representation method to explore resonances in $^{31}$Ne.
We have calculated the single-particle energies for bound and resonant states
together with their evolutions with deformation. The results show that the
$p-$wave resonances appear clearly in the complex momentum plane accompanied
with the $p-f$ inversion in the single-particle levels. As it happens the $p-f$
inversion, the calculated energy, width, and occupation probabilities of major
components in the level occupied by valance neutron support a $p-$wave halo for
$^{31}$Ne.",1707.00246v1
2017-06-02,Linear frequency conversion via sudden merging of resonances in time-variant metasurfaces,"Energy conversion in a physical system requires time-translation invariance
breaking according to Noether's theorem. Closely associated with this
symmetry-conservation relation, the frequencies of electromagnetic waves are
found to be converted as the waves propagate through a temporally varying
medium. Thus, effective temporal control of the medium, be it artificial or
natural, through which the waves are propagating, lies at the heart of linear
optical frequency conversion. Here, we propose rapidly time-variant
metasurfaces as a frequency-conversion platform and experimentally demonstrate
their efficacy at THz frequencies. The proposed metasurface is designed for the
sudden merging of two distinct resonances into a single resonance upon
ultrafast optical excitation. From this spectrally-engineered temporal boundary
onward, the merged-resonance frequency component is radiated. In addition,
temporal coherence of the two original resonating modes with respect to the
abrupt temporal boundary is found to be strongly related to the amount of
frequency conversion as well as the phase of the converted wave. Due to their
design flexibility, time-variant metasurfaces may become on-demand frequency
synthesizers for various frequency ranges.",1706.00664v1
2017-10-01,"Elastic metamaterial with simultaneously negative Mass Density, Bulk Modulus and Shear Modulus","We present a study of elastic metamaterial that possesses multiple local
resonances. We demonstrated that the elastic metamaterial can have
simultaneously three negative effective parameters, i.e., negative effective
mass, effective bulk modulus and effective shear modulus at a certain frequency
range. Through the analysis of the resonant field, it has been elucidated that
the three negative parameters are induced by dipolar, monopolar and quadrupolar
resonance respectively. The dipolar and monopolar resonances result into the
negative band for longitudinal waves, while the dipolar and quadrupolar
resonances cause the negative band for transverse waves. The two bands have an
overlapping frequency regime. A simultaneously negative refraction for both
longitudinal waves and transverse waves has been demonstrated in the system.",1710.03681v1
2020-01-31,A mathematical and numerical framework for gradient meta-surfaces built upon periodically repeating arrays of Helmholtz resonators,"In this paper a mathematical model is given for the scattering of an incident
wave from a surface covered with microscopic small Helmholtz resonators, which
are cavities with small openings. More precisely, the surface is built upon a
finite number of Helmholtz resonators in a unit cell and that unit cell is
repeated periodically. To solve the scattering problem, the mathematical
framework elaborated in [Ammari et al., Asympt. Anal., 2019] is used. The main
result is an approximate formula for the scattered wave in terms of the lengths
of the openings. Our framework provides analytic expressions for the scattering
wave vector and angle and the phase-shift. It justifies the apparent
absorption. Moreover, it shows that at specific lengths for the openings and a
specific frequency there is an abrupt shift of the phase of the scattered wave
due to the subwavelength resonances of the Helmholtz resonators. A numerically
fast implementation is given to identify a region of those specific values of
the openings and the frequencies.",2001.11587v1
2021-01-03,The effect of flow on resonant absorption of slow MHD waves in magnetic flux tubes,"In this paper, we study kink and sausage oscillations in the presence of
longitudinal background flow. We study resonant absorption of the kink and
sausage modes in the slow continuum under magnetic pore conditions in the
presence of flow. we determine the dispersion relation then solve it
numerically, and find the frequencies and damping rates of the slow kink and
sausage surface modes. We also, obtain analytical solution for the damping rate
of the slow surface mode in the long wavelength limit. We show that in the
presence of plasma flow, resonance absorption can result in strong damping for
forward waves and can be considered as an efficient mechanism to justify the
extremely rapid damping of slow surface sausage waves observed in magnetic
pores. Also, the plasma flow reduces the efficiency of resonance absorption to
damp backward waves. Furthermore, for the pore conditions, the resonance
instability is avoided in our model.",2101.02064v1
2022-02-04,Absorption characteristics of large acoustic metasurfaces,"Metasurfaces formed of arrays of subwavelength resonators are often tuned to
'critically couple' with incident radiation, so that at resonance dissipative
and radiative damping are balanced and absorption is maximised. Such design
criteria are typically derived assuming an infinite metasurface, whereas the
absorption characteristics of finite metasurfaces, even very large ones, can be
markedly different in certain frequency intervals. This is due to the
excitation of surface waves, intrinsic to resonant metasurfaces, and especially
meta-resonances, namely collective resonances where the surface waves form
standing-wave patterns over the planar metasurface domain. We illustrate this
issue using a detailed model of a Helmholtz-type acoustic metasurface formed of
cavity-neck pairs embedded into a rigid substrate, with geometric and
dissipation effects included from first principles (R. Brand\~ao and O.
Schnitzer, Wave Motion, 97 102583, 2020).",2202.03175v2
2023-04-10,Wave reflections and resonance in a Mach 0.9 turbulent jet,"This work aims to provide a more complete understanding of the resonance
mechanisms that occur in turbulent jets at high subsonic Mach number, as shown
by Towne et al. (2017). Resonance was suggested by that study to exist between
upstream- and downstream-travelling guided waves. Five possible resonance
mechanisms were postulated, each involving different families of guided waves
that reflect in the nozzle exit plane and a number of downstream turning
points. But the study did not show which of these mechanisms are active in the
flow. In this work, the waves underpinning resonance are identified via a
biorthogonal projection of the Large Eddy Simulation data on eigenbases
provided by locally parallel linear stability analysis. Two of the scenarios
postulated by Towne et al. (2017) are thus confirmed to exist in the turbulent
jet data. The reflection-coefficients in the nozzle exit and turning-point
planes are, furthermore, identified.",2304.04436v1
2018-04-17,Turbulence of capillary waves forced by steep gravity waves,"We study experimentally the dynamics and statistics of capillary waves forced
by random steep gravity waves mechanically generated in laboratory. Capillary
waves are produced here by gravity waves from nonlinear wave interactions.
Using a spatio-temporal measurement of the free-surface, we characterize
statistically the random regimes of capillary waves in the spatial and temporal
Fourier spaces. For a significant wave steepness ($0.2-0.3$), power-law spectra
are observed both in space and time, defining a turbulent regime of capillary
waves transferring energy from large scale to small scale. Analysis of temporal
fluctuations of spatial spectrum demonstrates that the capillary power-law
spectra result from the temporal averaging over intermittent and strong
nonlinear events transferring energy to small scale in a fast time scale, when
capillary wave trains are generated in a way similar to the parasitic capillary
wave generation mechanism. The frequency and wavenumber power-law exponents of
wave spectrum are found to be in agreement with those of the weakly nonlinear
Wave Turbulence Theory. However, the energy flux is not constant through the
scales and the wave spectrum scaling with this flux is not in good agreement
with Wave Turbulence Theory. These results suggest that theoretical
developments beyond the classic Wave Turbulence Theory are necessary to
describe the dynamics and statistics of capillary waves in natural environment.
In particular, in presence of broad scale viscous dissipation and strong
nonlinearity, the role of non-local and non-resonant interactions could be
reconsidered.",1804.06422v1
2018-05-31,Evolution of electron distribution driven by nonlinear resonances with intense field-aligned chorus waves,"Resonant electron interaction with whistler-mode chorus waves is recognized
as one of the main drivers of radiation belt dynamics. For moderate wave
intensity, this interaction is well described by quasi-linear theory. However,
recent statistics of parallel propagating chorus waves have demonstrated that
5-20% of the observed waves are sufficiently intense to interact nonlinearly
with electrons. Such interactions include phase trapping and phase bunching
(nonlinear scattering) effects not described by the quasi-linear diffusion. For
sufficiently long (large) wave-packets, these nonlinear effects can result in
very rapid electron acceleration and scattering. In this paper we introduce a
method to include trapping and nonlinear scattering into the kinetic equation
describing the evolution of the electron distribution function. We use
statistics of Van Allen Probes and Time History of Events and Macroscale
Interactions during Substorms (THEMIS) observations to determine the
probability distribution of intense, long wave-packets as function of power and
frequency. Then we develop an analytical model of particle resonance of an
individual particle with an intense chorus wave-packet and derive the main
properties of this interaction: probability of electron trapping, energy change
due to trapping and nonlinear scattering. These properties are combined in a
nonlocal operator acting on the electron distribution function. When multiple
waves are present, we average the obtained operator over the observed
distributions of waves and examine solutions of the resultant kinetic equation.
We also examine energy conservation and its implications in systems with the
nonlinear wave-particle interaction.",1806.00066v1
2005-07-28,Transverse spin waves in isotropic ferromagnets,"The comparison of transverse spin wave spectra and its attenuation in
Heisenberg ferromagnet and in ferromagnetic Fermi liquid as well in polarized
Fermi liquid is undertaken. The transverse spin waves frequency in polarized
paramagnetic Fermi liquid as well in a Fermi liquid with spontaneous
magnetization is found to be proportional to the square of the wave vector with
complex diffusion coefficient such that the damping has a finite value
proportional to the scattering rate of quasiparticles at T=0.
  This behavior of polarized Fermi liquid contrasts with the behavior of
Heisenberg ferromagnet in hydrodynamic regime where the transverse spin wave
attenuation appears in terms proportional to the wave vector in fourth power.
  The reactive part of diffusion coefficient in paramagnetic state at T=0
proves to be inversely proportional to magnetization whereas in ferromagnetic
state it is directly proportional to magnetization. The dissipative part of
diffusion coefficient at T=0 in paramagnetic state is polarization independent,
whereas in ferromagnetic state it is proportional to square of magnetization.
Moreover, the spin wave spectrum in ferromagnetic Fermi liquid proves to be
unstable that demonstrates the difficulty of the Fermi liquid description of
itinerant ferromagnetism.",0507676v1
2007-08-13,Total Reflection and Negative Refraction of Dipole-Exchange Spin Waves at Magnetic Interfaces: Micromagnetic Modeling Study,"We demonstrated that dipole-exchange spin waves traveling in geometrically
restricted magnetic thin films satisfy the same laws of reflection and
refraction as light waves. Moreover, we found for the first time novel wave
behaviors of dipole-exchange spin waves such as total reflection and negative
refraction. The total reflection in laterally inhomogeneous thin films composed
of two different magnetic materials is associated with the forbidden modes of
refracted dipole-exchange spin waves. The negative refraction occurs at a 90
degree domain-wall magnetic interface that is introduced by a cubic magnetic
anisotropy in the media, through the anisotropic dispersion of dipole-exchange
spin waves.",0708.1642v1
2014-03-11,Overcoming damping in spin wave propagation: A continuous excitation approach to determine time-dependent dispersion diagrams in 2D magnonic crystals,"We propose an alternative micromagnetic approach to determine the spin wave
dispersion relations in magnonic structures. Characteristic of the method is
that a limited area of the system is continuously excited with a spatially
uniform oscillating field, tuned at a given frequency. After a transitory time,
the regime magnetization dynamics is collected and a spatial Fourier analysis
on it determines the frequency vs wave vector relation. Combining several
simulations in any predetermined range of frequencies, at any resolution, we
investigate the dispersion relations for different kinds of magnonic crystals:
a dot array, an antidot array, and a bicomponent film. Especially compared to
traditional pulse-excitation methods this technique has many advantages. First,
the excitation power is concentrated at a single frequency, allowing the
corresponding spin waves to propagate with very low attenuation, resulting in a
higher k-space resolution. Second, the model allows to include very large wave
vector components, necessary to describe the high-frequency response of
non-quantized spin waves in quasi-continuous systems. Finally, we address some
possible experimental opportunities with respect to excitation/detection
techniques over large distances and the observation of the odd/even symmetry of
spin waves using Brillouin light scattering.",1403.2549v1
2018-11-17,Transverse spin and surface waves in acoustic metamaterials,"We consider spin angular momentum density in inhomogeneous acoustic fields:
evanescent waves and surface waves at interfaces with negative-density
metamaterials. Despite being purely longitudinal (curl-free), acoustic waves
possess intrinsic vector properties described by the velocity field. Motivated
by the recent description and observation of the spin properties in elastic and
acoustic waves, we compare these properties with their well-known
electromagnetic counterparts. Surprisingly, both the transverse spin of
evanescent waves and the parameters of surface waves are very similar in
electromagnetism and acoustics. We also briefly analyze the important role of
dispersion in the description of the energy and spin densities in acoustic
metamaterials.",1811.07159v2
2019-08-31,High-fidelity magnonic gates for surface spin waves,"We study the propagation of surface spin waves in two wave guides coupled
through the dipole-dipole interaction. Essential for the observations made here
is the magneto-electric coupling between the spin waves and the effective
ferroelectric polarization. This allows an external electric field to act on
spin waves and to modify the band gaps of magnonic excitations in individual
layers. By an on/off switching of the electric field and/or varying its
strength or direction with respect to the equilibrium magnetization, it is
possible to permit or ban the propagation of the spin waves in selected
waveguide. We propose experimentally feasible nanoscale device operating as a
high fidelity surface wave magnonic gate.",1909.00162v1
2015-08-04,General classical and quantum-mechanical description of magnetic resonance: An application to electric-dipole-moment experiments,"A general theoretical description of a magnetic resonance is presented. This
description is necessary for a detailed analysis of spin dynamics in
electric-dipole-moment experiments in storage rings. General formulas
describing a behavior of all components of the polarization vector at the
magnetic resonance are obtained for an arbitrary initial polarization. These
formulas are exact on condition that the nonresonance rotating field is
neglected. The spin dynamics is also calculated at frequencies far from
resonance with allowance for both rotating fields. A general quantum-mechanical
analysis of the spin evolution at the magnetic resonance is fulfilled and the
full agreement between the classical and quantum-mechanical approaches is
shown. Quasimagnetic resonances for particles and nuclei moving in
noncontinuous perturbing fields of accelerators and storage rings are
considered. Distinguishing features of quasimagnetic resonances in storage ring
electric-dipole-moment experiments are investigated in detail. The exact
formulas for the effect caused by the electric dipole moment are derived. The
difference between the resonance effects conditioned by the rf electric-field
flipper and the rf Wien filter is found and is calculated for the first time.
The existence of this difference is crucial for the establishment of a consent
between analytical derivations and computer simulations and for checking spin
tracking programs. Main systematical errors are considered.",1508.00742v3
2023-11-29,Spin Dynamics of Planets in Resonant Chains,"About a dozen exoplanetary systems have been discovered with three or more
planets participating in a sequence of mean-motion resonances. The unique and
complex architectures of these so-called ""resonant chains"" motivate efforts to
characterize their planets holistically. In this work, we perform a
comprehensive exploration of the spin-axis dynamics of planets in resonant
chains. Planetary spin states are closely linked with atmospheric dynamics and
habitability and are thus especially relevant to resonant chains like
TRAPPIST-1, which hosts several temperate planets. Considering a set of
observed resonant chains, we calculate the equilibrium states of the planetary
axial tilts (""obliquities""). We show that high obliquity states exist for
$\sim60\%$ of planets in our sample, and many of these states can be stable in
the presence of tidal dissipation. Using case studies of two observed systems
(Kepler-223 and TOI-1136), we demonstrate how these high obliquity states could
have been attained during the initial epoch of disk-driven orbital migration
that established the resonant orbital architectures. We show that the
TRAPPIST-1 planets most likely have zero obliquities, with the possible
exception of planet d. Overall, our results highlight that both the orbital and
spin states of resonant chains are valuable relics of the early stages of
planet formation and evolution.",2311.17908v1
2015-05-12,Tilting Jupiter (a bit) and Saturn (a lot) During Planetary Migration,"We study the effects of planetary late migration on the gas giants
obliquities. We consider the planetary instability models from Nesvorny &
Morbidelli (2012), in which the obliquities of Jupiter and Saturn can be
excited when the spin-orbit resonances occur. The most notable resonances occur
when the $s_7$ and $s_8$ frequencies, changing as a result of planetary
migration, become commensurate with the precession frequencies of Jupiter's and
Saturn's spin vectors. We show that Jupiter may have obtained its present
obliquity by crossing of the $s_8$ resonance. This would set strict constrains
on the character of migration during the early stage. Additional effects on
Jupiter's obliquity are expected during the last gasp of migration when the
$s_7$ resonance was approached. The magnitude of these effects depends on the
precise value of the Jupiter's precession constant. Saturn's large obliquity
was likely excited by capture into the $s_8$ resonance. This probably happened
during the late stage of planetary migration when the evolution of the $s_8$
frequency was very slow, and the conditions for capture into the spin-orbit
resonance with $s_8$ were satisfied. However, whether or not Saturn is in the
spin-orbit resonance with $s_8$ at the present time is not clear, because the
existing observations of Saturn's spin precession and internal structure models
have significant uncertainties.",1505.02938v1
2019-05-05,Dipole coupling of a tunable hole double quantum dot in germanium hut wire to a microwave resonator,"The germanium (Ge) hut wire system has strong spin-orbit coupling, a long
coherence time due to a very large heavy-light hole splitting, and the
advantage of site-controlled large-scale hut wire positioning. These properties
make the Ge hut wire a promising candidate for the realization of strong
coupling of spin to superconducting resonators and scalability for multiple
qubit coupling. We have coupled a reflection line resonator to a hole double
quantum dot (DQD) formed in Ge hut wire. The amplitude and phase responses of
the microwave resonator revealed that the charge stability diagrams of the DQD
are in good agreement with those obtained from transport measurements. The DQD
interdot tunneling rate is shown to be tunable from 6.2 GHz to 8.5 GHz, which
demonstrates the ability to adjust the frequency detuning between the qubit and
the resonator. Furthermore, we achieved a hole-resonator coupling strength of
up to 15 MHz, with a charge qubit decoherence rate of 0.28 GHz. Meanwhile the
hole spin-resonator coupling rate was estimated to be 3 MHz. These results
suggest that holes of a DQD in a Ge hut wire are dipole coupled to microwave
photons, potentially enabling tunable hole spin-photon interactions in Ge with
an inherent spin-orbit coupling.",1905.01586v2
2013-10-29,Wave packet dynamics and zitterbewegung of heavy holes in a quantizing magnetic field,"In this work we study wave packet dynamics and $zitterbewegung$, an
oscillatory quantum motion, of heavy holes in III-V semiconductor quantum wells
in presence of a quantizing magnetic field. It is revealed that a Gaussian
wave-packet describing a heavy hole diffuses asymmetrically along the circular
orbit while performing cyclotron motion. The wave packet splits into two peaks
with unequal amplitudes after a certain time depending on spin-orbit coupling
constant. This unequal splitting of the wave packet is attributed to the cubic
Rashba interaction for heavy holes. The difference in the peak amplitudes
disappears with time. At a certain time the two peaks diffuse almost along the
entire cyclotron orbit. Then tail and head of the diffused wave packet
interfere and as a result a completely randomized pattern of the wave packet is
observed. The diffusion rate of the wave packet increases with increase of the
spin-orbit interaction strength. Also strong spin-orbit coupling expedite the
splitting and the randomization of the wave packet. We also study the
$zitterbewegung$ in various physical observables such as position, charge
current and spin angular momentum of the heavy hole. The $zitterbewegung$
oscillations are very much sensitive to the initial wave vector of the Gaussian
wave packet and the strength of the Rashba spin-orbit coupling.",1310.7749v2
1999-03-01,Defect-Induced Resonant Tunneling of Electromagnetic Waves Through a Polariton Gap,"We consider tunneling of electromagnetic waves through a polariton band gap
of a 1-D chain of atoms. We analytically demonstrate that a defect embedded in
the structure gives rise to the resonance transmission at the frequency of a
local polariton state associated with the defect.",9903027v1
1998-07-20,Detection of Scalar Particles in Gravitational Waves from Resonant-Mass Detectors of Spherical Shape,"We report on some recent work, which points out the relevance of future
measurements of gravitational waves by resonant-mass detectors of spherical
shape for theories of gravity of non-Einstein type.",9807052v1
2004-09-03,Bifurcation of free vibrations for completely resonant wave equations,"We prove existence of small amplitude, 2 pi/omega -periodic in time solutions
of completely resonant nonlinear wave equations with Dirichlet boundary
conditions for any frequency omega belonging to a Cantor-like set of positive
measure and for a generic set of nonlinearities. The proof relies on a suitable
Lyapunov-Schmidt decomposition and a variant of the Nash-Moser Implicit
Function Theorem.",0409052v1
2005-04-20,Quasi-periodic solutions of completely resonant forced wave equations,"We prove existence of quasi-periodic solutions with two frequencies of
completely resonant, periodically forced nonlinear wave equations with periodic
spatial boundary conditions. We consider both the cases the forcing frequency
is: (Case A) a rational number and (Case B) an irrational number.",0504406v1
2005-12-19,Finite amplitude waves under a small resonant driving force,"We construct a special asymptotic solution for the forced Boussinesq
equation. The perturbation is small and oscillates with a slowly varied
frequency. The slow passage through the resonance generates waves with the
finite amplitude. This phenomenon is described in details.",0512049v1
2006-07-17,Resonance-assisted decay of nondispersive wave packets,"We present a quantitative semiclassical theory for the decay of nondispersive
electronic wave packets in driven, ionizing Rydberg systems. Statistically
robust quantities are extracted combining resonance assisted tunneling with
subsequent transport across chaotic phase space and a final ionization step.",0607035v1
2006-07-04,Sagnac effect in resonant microcavities,"The Sagnac effect in two dimensional (2D) resonant microcavities is studied
theoretically and numerically. The frequency shift due to the Sagnac effect
occurs as a threshold phenomenon for the angular velocity in a rotating
microcavity. Above the threshold, the eigenfunctions of a rotating microcavity
become rotating waves while they are standing waves below the threshold.",0607016v1
2007-01-15,Imaging using nano metallic films: from evanescent wave lens to resonant tunnelling lens,"A thin metal slab is known to be able to focus the near fields of TM wave of
a point source. Here, we show that a thin metal slab in fact possesses a
far-field image and through a simple modification on the system by resonance
tunneling, a double metal slab can give a bright image with both the far-field
and the near-field details.",0701172v1
2007-01-16,Splitting of Resonant Frequencies of Acoustic Waves in Rotating Compressible Fluid,"It is shown that in a rotating compressible fluid the resonant frequencies
(measured in a system of reference rotating together with the medium) for the
azimuthally running acoustic waves are split into two components. The received
results can be of practical significance as a basis of a method of measurements
of angular speed of medium and for acoustics of rotating technical devices.",0701184v1
2008-08-26,Displacement-noise-free resonant speed meter for gravitational-wave detection,"We demonstrate that speedmeter, based on double pumped resonant Sagnac
interferometer, can be used as a displacement noise free gravitational-wave
(GW) detector. The displacement noise of cavity mirrors can be completely
excluded through a proper linear combination of the output signals. We show
that in low-frequency region the obtained displacement-noise-free response
signal is stronger than the one in previously proposed displacement noise free
interferometers.",0808.3445v1
2011-03-19,Local energy decay for wave equation in the absence of resonance at zero energy in 3D,"In this paper we study spectral properties associated to Schrodinger operator
with potential that is an exponential decaying function. As applications we
prove local energy decay for solutions to the perturbed wave equation and lack
of resonances for the NLS.",1103.3760v1
2011-09-26,Space-Time resonances and the null condition for (first order) systems of wave equations,"In this manuscript we prove global existence and linear asymptotic behavior
of small solutions to nonlinear wave equations. We assume that the quadratic
part of the nonlinearity satisfies a non-resonant condition which is a
generalization of the null condition given by Klainerman.",1109.5662v2
2012-11-16,Complete Experiments for Pion Photoproduction,"The possibilities of a model-independent partial wave analysis for pion, eta
or kaon photoproduction are discussed in the context of complete experiments.
It is shown that the helicity amplitudes obtained from at least 8 polarization
observables including beam, target and recoil polarization can not be used to
analyze nucleon resonances. However, a truncated partial wave analysis, which
requires only 5 observables will be possible with minimal model assumptions.",1211.3927v1
2013-09-04,"Comment to the note ""Counting of discrete Rossby/drift wave resonant triads"", arXiv:1309.0405","The main purpose of this note is clarify the following misunderstanding
apparent in the note arXiv:1309.0405 by M. Bustamante, U. Hayat, P. Lynch, B.
Quinn; [1]: the authors erroneously assume that in the manuscript
arXiv:1307.8272 by A. Kartashov and E. Kartashova, [2], resonant triads with
real amplitudes are counted whereas it can be seen explicitly from the form of
dynamical system that wave amplitudes are complex.",1309.0992v1
2013-09-24,Resonant radiation shed by dispersive shock waves,"We show that dispersive shock waves resulting from the nonlinearity
overbalancing a weak leading-order dispersion can emit resonant radiation owing
to higher-order dispersive contributions. We analyze such phenomenon for the
defocusing nonlinear Schroedinger equation, giving criteria for calculating the
radiated frequency based on the estimate of the shock velocity, revealing also
a diversity of possible scenarios depending on the order and magnitude of the
dispersive corrections.",1309.6227v1
2017-07-12,Four wave mixing in 3C SiC Ring Resonators,"We demonstrate frequency conversion by four wave mixing at telecommunication
wavelengths using an integrated platform in 3C SiC. The process was enhanced by
high-Q and small modal volume ring resonators, allowing the use of mW-level CW
powers to pump the nonlinear optical process. We retrieved the nonlinear
refractive index $n_{2}=(5.31\pm 0.04)\times 10^{-19} m^{2}/W$ of 3C SiC and
observed a signal attributed to Raman gain in the structure.",1707.03645v1
2017-05-28,Analysis of EUV Solar Spectrum with Gravity Induced Resonant Emission,"Gravity Induced Resonant Emission (GIRE) is a new phenomenon recently
reported; we have analyzed the solar emissions on the basis of GIRE. We have
computed the EUV solar spectrum using GIRE wave length as a part of studying
coronal heating problem. We find all the solar observations converge in GIRE
and the GIRE wave length is sufficient to study all the solar emissions.",1705.09956v1
2019-06-14,The invisibility via anomalous localized resonance of a source for electromagnetic waves,"We study the invisibility via anomalous localized resonance of a general
source for electromagnetic waves in the setting of doubly complementary media.
As a result, we show that cloaking is achieved if the power is blown up. We
also reveal a critical length for the invisibility of a source that occurs when
the plasmonic structure is complementary to an annulus of constant, isotropic
medium.",1906.06152v1
2021-04-15,On the possibility of resonant acceleration of charged particles by the field of a transverse electromagnetic wave in vacuum,"The analytical and numerical analysis of the dynamics of charged particles in
the field of an intensive transverse electromagnetic wave in a vacuum presented
in the article. Identifies the conditions for resonant acceleration of
particles. These conditions are formulated. The features and the mechanism of
this acceleration are discussed.",2104.11603v1
2016-11-27,Nonlinear Wave Equation with Damping: Periodic Forcing and Non-Resonant Solutions to the Kuznetsov Equation,"Existence of non-resonant solutions of time-periodic type are established for
the Kuznetsov equation with a periodic forcing term. The equation is considered
in a three-dimensional whole-space, half-space and bounded domain, and with
both non-homogeneous Dirichlet and Neumann boundary values. A method based on
Lp estimates of the corresponding linearization, namely the wave equation with
Kelvin-Voigt damping, is employed.",1611.08883v1
1994-07-28,Frustrated Bonds and Long Range Order in Quasi-2D Magnets,"We employ the Schwinger boson mean-field approach to study the effects of
arbitrary frustrated bonds and plaquettes (formed from four frustrated bonds)
in two-dimensional ferro- and antiferromagnets on the spin-wave spectrum and
the correlation length at finite temperatures. We distinguish between strongly
frustrated bonds (plaquettes), when the frustrated coupling $J^\prime$ exceeds
the spin canting threshold $J_c$, and weakly frustrated bonds (plaquettes),
with $J^\prime <J_c, (J_c-J^\prime)/J_c\sim 1$. It is shown that in
antiferromagnets the amplitude of spin-wave scattering on strongly frustrated
bonds or plaquettes grows with the decrease of the temperature. A small amount
of such defects reduces significantly the spin-wave stiffness and the
correlation length at low temperatures. As a result, the quasi-2D N\'eel
temperature is sharply suppressed. Quantum fluctuations are also considered and
their effect on the spin-wave spectrum is shown to be of the order of
$(2S)^{-2}\ln^{-1}2S$ in the large spin limit. For weakly frustrated
(nonfrustrated) defect bonds (plaquettes) the spin-wave stiffness
renormalization is of the order of the dopant concentration and does not depend
on the temperature. The results account for the observed properties of doped
quasi-2D $La_2CuO_{4+x}$.",9407111v1
1999-05-11,Invariant spin coherent states and the theory of quantum antiferromagnet in a paramagnetic phase,"The consistent theory of the Heisenberg quantum antiferromagnet in the
disordered phase with short range antiferromagnetic order was developed on the
basis of the path integral for the spin coherent states. We have presented the
Lagrangian of the theory in a form which is explicitly invariant under
rotations and have found natural variables in the term of which one can
construct a natural perturbation theory. The short wave spin fluctuations are
similar to the spin wave theory ones, and the long wave spin fluctuations are
governed by the nonlinear sigma model. We have also demonstrated that the short
wave spin fluctuations have to be considered accurately in the framework of the
discrete version in time of the path integral. In the framework of our approach
we have obtained the response function for the spin fluctuations for the whole
region of the frequency $\omega$ and the wave vector ${\bf k}$ and have
calculated the free energy of the system.",9905132v3
2003-06-26,Finite-size spin-wave theory of a collinear antiferromagnet,"The ground-state and low-energy properties of the two-dimensional $J_1{-}J_2$
Heisenberg model in the collinear phase are investigated using finite-size
spin-wave theory [Q. F. Zhong and S. Sorella, {\em Europhys. Lett.} {\bf 21},
629 (1993)], and Lanczos exact diagonalizations. For spin one-half -- where the
effects of quantization are the strongest -- the spin-wave expansion turns out
to be quantitatively accurate for $J_2/J_1\gtrsim 0.8$. In this regime, both
the magnetic structure factor and the spin susceptibility are very close to the
spin-wave predictions. The spin-wave estimate of the order parameter in the
collinear phase, $m^\dagger\simeq 0.3$, is in remarkable agreement with recent
neutron scattering measurements on ${\rm Li_2VOSiO_4}$.",0306679v2
2003-09-29,Magnons in CMR pyrochlore Tl2Mn2O7,"Well defined spin waves were observed when the spin dynamics of Tl2Mn2O7, the
first pyrochlore compound found to exhibit colossal magnetoresistance, was
measured [J.W.Lynn et al., Phys.Rev.Lett. 80,4582(1998)], in stark contrast
with the experimental results on the larger family of magnetoresistive
manganites with perovskite structure. In this work, we present our calculation
for the spin waves in Tl2Mn2O7, which we described using the microscopic
generic model proposed recently for this compound [C.I.Ventura and M.A.Gusmao,
Phys.Rev.B 65, 14422(2002)]. We have employed a canonical transformation to
determine perturbatively the effective spin-wave Hamiltonian, obtaining
therefrom the renormalization of the ferromagnetic spin waves related to the
localized Mn$^{4+}$ spins, due to their coupling with the conduction electrons
present. We have calculated the magnon dispersion relations along different
paths in the first Brillouin zone, comparing them with those which are obtained
for an ideal isotropic ferromagnet. This comparison evidences an agreement
between the ferromagnetic magnons obtained from the generic model and the bare
spin waves, such as had been found in neutron scattering experiments.",0309684v1
2004-02-17,Spin Waves in Antiferromagnetic Spin Chains with Long Range Interactions,"We study antiferromagnetic spin chains with unfrustrated long-range
interactions that decays as a power law with exponent $\beta$, using the spin
wave approximation. We find for sufficiently large spin $S$, the Neel order is
stable at T=0 for $\beta < 3$, and survive up to a finite Neel temperature for
$\beta < 2$, validating the spin-wave approach in these regimes. We estimate
the critical values of $S$ and $T$ for the Neel order to be stable. The spin
wave spectra are found to be gapless but have non-linear momentum dependence at
long wave length, which is responsible for the suppression of quantum and
thermal fluctuations and stabilizing the Neel state. We also show that for
$\beta\le 1$ and for a large but finite-size system size $L$, the excitation
gap of the system approaches zero slower than $L^{-1}$, a behavior that is in
contrast to the Lieb-Schulz-Mattis theorem.",0402445v2
2004-12-29,Spin wave analysis of Heisenberg magnets in restricted geometries,"In the last decade it has been proven that the standard spin wave theory was
able to provide accurate zero-temperature results for a number of
low-dimensional Heisenberg spin systems. In this chapter we introduce the main
ingredients of the spin-wave technique using as a working model the two-leg
mixed-spin ferrimagnetic ladder and the Dyson--Maleev boson formalism up to
second order in the spin-wave interaction. In the remainder, we survey typical
applications in low-space dimensionality as well as some recent modifications
of the theory admitting a quantitative analysis in magnetically disordered
phases. The presented spin-wave results are compared with available numerical
estimates.",0412742v1
2008-12-22,Spin-wave contributions to current-induced domain wall dynamics,"We examine theoretically the role of spin-waves on current-induced domain
wall dynamics in a ferromagnetic wire. At room temperature, we find that an
interaction between the domain wall and the spin waves appears when there is a
finite difference between the domain wall velocity $\dot{x}_0$ and the spin
current $u$. Three important consequences of this interaction are found.
Firstly, spin-wave emission leads to a Landau-type damping of the
current-induced domain wall motion towards restoring the solution $\dot{x}_0 =
u$, where spin angular momentum is perfectly transfered from the conduction
electrons to the domain wall. Secondly, the interaction leads to a modification
of the domain wall width and mass, proportional to the kinetic energy of the
domain wall. Thirdly, the coupling by the electrical current between the domain
wall and the spin waves leads to temperature-dependent effective wall mass.",0812.4084v1
2011-03-15,Nonlinear wave interaction and spin models in the MHD regime,"Here we consider the influence on the electron spin in the MHD regime.
Recently developed models which include spin-velocity correlations are taken as
a starting point. A theoretical argument is presented, suggesting that in the
MHD regime a single fluid electron model with spin correlations is equivalent
to a model with spin-up and spin-down electrons constituting different fluids,
but where the spin-velocity correlations are omitted. Three wave interaction of
2 shear Alfven waves and a compressional Alfven wave is then taken as a model
problem to evaluate the asserted equivalence. The theoretical argument turns
out to be supported, as the predictions of the two models agree completely.
Furthermore, the three wave coupling coefficients obey the Manley-Rowe
relations, which give further support to the soundness of the models and the
validity of the assumptions made in the derivation. Finally we point out that
the proposed two-fluid model can be incorporated in standard Particle-In-Cell
schemes with only minor modifications.",1103.2932v1
2013-12-17,Superconducting pairing in the spin-density-wave phase of iron pnictides,"Some of the iron pnictides show coexisting superconductivity and
spin-density-wave order. We study the superconducting pairing instability in
the spin-density-wave phase. Assuming that the pairing interaction is due to
spin fluctuations, we calculate the effective pairing interactions in the
singlet and triplet channels by summing the bubble and ladder diagrams taking
the reconstructed band structure into account. The leading pairing
instabilities and the corresponding superconducting gap structures are then
obtained from the superconducting gap equation. We illustrate this approach for
a minimal two-band model of the pnictides. Analytical and numerical results
show that the existence of propagating magnons in the spin-density-wave phase
strongly enhances the pairing in both the singlet and the spin s_z=0 triplet
channel. Over a limited parameter range, a spin s_z=0 triplet p_x-wave state is
the dominant instability. It competes with various singlet states, which have
mostly s^\pm-type structures. We analyze the effect of various symmetry-allowed
interactions on the pairing in some detail.",1312.4720v2
2014-10-26,Spin flip statistics and Spin wave interference patterns in Ising ferromagnetic films: A Monte Carlo study,"The spin wave interference is studied in two dimensional Ising ferromagnet
driven by two coherent spherical magnetic field waves by Monte Carlo
simulation. The spin waves are found to propagate and interfere according to
the classic rule of interference pattern generated by two point sources. The
interference pattern of spin wave is observed in one boundary of the lattice.
The interference pattern is detected and studied by spin flip statistics at
high and low temperatures. The destructive interference is manifested as the
large number of spin flips and vice versa.",1410.7023v4
2016-05-22,Spin control of light with hyperbolic metasurfaces,"Transverse spin angular momentum is an inherent feature of evanescent waves
which may have applications in nanoscale optomechanics, spintronics, and
quantum information technology due to the robust spin-directional coupling.
Here we analyze a local spin angular momentum density of hybrid surface waves
propagating along anisotropic hyperbolic metasurfaces. We reveal that, in
contrast to bulk plane waves and conventional surface plasmons at isotropic
interfaces, the spin of the hybrid surface waves can be engineered to have an
arbitrary angle with the propagation direction. This property allows to tailor
directivity of surface waves via the magnetic control of the spin projection of
quantum emitters, and it can be useful for optically controlled spin transfer.",1605.06781v2
2018-06-22,Spin-flavor oscillations of Dirac neutrinos in a plane electromagnetic wave,"We study spin and spin-flavor oscillations of Dirac neutrinos in a plane
electromagnetic wave with circular polarization. The evolution of massive
neutrinos with nonzero magnetic moments in the field of an electromagnetic wave
is based on the exact solution of the Dirac-Pauli equation. We formulate the
initial condition problem to describe spin-flavor oscillations in an
electromagnetic wave. The transition probabilities for spin and spin-flavor
oscillations are obtained. In case of spin-flavor oscillations, we analyze the
transition and survival probabilities for different neutrino magnetic moments
and various channels of neutrino oscillations. As an application of the
obtained results, we study the possibility of existence of
$\nu_{e\mathrm{L}}\to\nu_{\mu\mathrm{R}}$ oscillations in an electromagnetic
wave emitted by a highly magnetized neutron star. Our results are compared with
findings of other authors.",1806.08719v2
2021-02-05,Symmetry-Driven Spin-Wave Gap Modulation in Nanolayered SrRuO3/SrTiO3 Heterostructures: Implications for Spintronic Applications,"A strong correlation between magnetic interaction and topological symmetries
leads to unconventional magneto-transport behavior. Weyl fermions induce
topologically protected spin-momentum locking, which is closely related to
spin-wave gap formation in magnetic crystals. Ferromagnetic SrRuO3, regarded as
a strong candidate for Weyl semimetal, inherently possesses a nonzero spin-wave
gap owing to its strong magnetic anisotropy. In this paper, we propose a method
to control the spin-wave dynamics by nanolayer designing of the SrRuO3/SrTiO3
superlattices. In particular, the six-unit-cell-thick SrRuO3 layers within the
superlattices undergo a phase transition in crystalline symmetry from
orthorhombic to tetragonal, as the thickness of the SrTiO3 layers is modulated
with atomic-scale precision. Consequently, the magnetic anisotropy, anomalous
Hall conductivity, and spin-wave gap could be systematically manipulated. Such
customization of magnetic anisotropy via nanoscale heterostructuring offers a
novel control knob to tailor the magnon excitation energy for future spintronic
applications, including magnon waveguides and filters. Our nanolayer approach
unveils the important correlation between the tunable lattice degrees of
freedom and spin dynamics in topologically non-trivial magnetic materials.",2102.03008v1
2021-04-14,Spin waves propagating through a stripe magnetic domain structure and their applications to reservoir computing,"Spin waves propagating through a stripe domain structure and reservoir
computing with their spin dynamics have been numerically studied with focusing
on the relation between physical phenomena and computing capabilities. Our
system utilizes a spin-wave-based device that has a continuous magnetic garnet
film and 1-input/72-output electrodes on the top. To control
spatially-distributed spin dynamics, a stripe magnetic domain structure and
amplitude-modulated triangular input waves were used. The spatially-arranged
electrodes detected spin vector outputs with various nonlinear characteristics
that were leveraged for reservoir computing. By moderately suppressing
nonlinear phenomena, our system achieves 100$\%$ prediction accuracy in
temporal exclusive-OR (XOR) problems with a delay step up to 5. At the same
time, it shows perfect inference in delay tasks with a delay step more than 7
and its memory capacity has a maximum value of 21. This study demonstrated that
our spin-wave-based reservoir computing has a high potential for edge-computing
applications and also can offer a rich opportunity for further understanding of
the underlying nonlinear physics.",2104.06794v1
2017-01-14,Paving Spin-Wave Fibers in Magnonic Nanocircuits Using Spin-Orbit Torque,"Recent studies have revealed that domain walls in magnetic nanostructures can
serve as compact, energy-efficient spin-wave waveguides for building magnonic
devices that are considered promising candidates for overcoming the challenges
and bottlenecks of today's CMOS technologies. However, imprinting long
strip-domain walls into magnetic nanowires remains a challenge, especially in
curved geometries. Here, through micromagnetic simulations, we present a method
for writing strip-domain walls into curved magnetic nanowires using spin-orbit
torque. We employ Y-shaped magnetic nanostructures as well as an S-shaped
magnetic nanowire to demonstrate the injection process. In addition, we verify
that the Y-shaped nanostructures that incorporate strip-domain walls can
function as superior spin-wave multiplexers, and that spin-wave propagation
along each conduit can be controllably manipulated. This spin-wave multiplexer
based on strip-domain walls is expected to become a key signal-processing
component in magnon spintronics.",1701.03886v1
2022-01-18,Adiabatic equatorial inspirals of a spinning body into a Kerr black hole,"The detection of gravitational waves from Extreme mass Ratio Inspirals
(EMRIs) by the future space-based gravitational-wave detectors demands the
generation of accurate enough waveform templates. Since the spin of the smaller
secondary body cannot be neglected for the detection and parameter estimation
of EMRIs, we study its influence on the phase of the gravitational waves from
EMRIs with spinning secondary. We focus on generic eccentric equatorial orbits
around a Kerr black hole. To model the spinning secondary object, we use the
Mathisson-Papapetrou-Dixon equations in the pole-dipole approximation.
Furthermore, we linearize in spin the orbital variables and the
gravitational-wave fluxes from the respective orbits. We obtain these fluxes by
using the Teukolsky formalism in the frequency domain. We derive the evolution
equations for the spin induced corrections to the adiabatic evolution of an
inspiral. Finally, through their numerical integration we find the
gravitational-wave phase shift between an inspiral of a spinning and a
non-spinnig body.",2201.07044v1
2024-02-01,Spin wave-driven variable-phase mutual synchronization in spin Hall nano-oscillators,"Spin-orbit torque can drive auto-oscillations of propagating spin wave (PSW)
modes in nano-constriction spin Hall nano-oscillators (SHNOs). These modes
allow both long-range coupling and the potential of controlling its phase --
critical aspect for nano-magnonics, spin wave logic, and Ising machines. Here,
we demonstrate PSW-driven variable-phase coupling between two nano-constriction
SHNOs and study how their separation and the PSW wave vector impact their
mutual synchronization. In addition to ordinary in-phase mutual
synchronization, we observe, using both electrical measurements and
phase-resolved $\mu-$Brillouin Light Scattering microscopy, mutual
synchronization with a phase that can be tuned from 0 to $\pi$ using the drive
current or the applied field. Micromagnetic simulations corroborate the
experiments and visualize how the PSW patterns in the bridge connecting the two
nano-constrictions govern the coupling. These results advance the capabilities
of mutually synchronized SHNOs and open up new possibilities for applications
in spin wave logic, unconventional computing, and Ising Machines.",2402.00586v1
2016-01-27,Dynamic nuclear polarization in a magnetic resonance force microscope experiment,"We report achieving enhanced nuclear magnetization in a magnetic resonance
force microscope experiment at 0.6 tesla and 4.2 kelvin using the dynamic
nuclear polarization (DNP) effect. In our experiments a microwire coplanar
waveguide delivered radiowaves to excite nuclear spins and microwaves to excite
electron spins in a 250 nm thick nitroxide-doped polystyrene sample. Both
electron and proton spin resonance were observed as a change in the mechanical
resonance frequency of a nearby cantilever having a micron-scale nickel tip.
NMR signal, not observable from Curie-law magnetization at 0.6 tesla, became
observable when microwave irradiation was applied to saturate the electron
spins. The resulting NMR signal's size, buildup time, dependence on microwave
power, and dependence on irradiation frequency was consistent with a transfer
of magnetization from electron spins to nuclear spins. Due to the presence of
an inhomogenous magnetic field introduced by the cantilever's magnetic tip, the
electron spins in the sample were saturated in a microwave-resonant slice 10's
of nm thick. The spatial distribution of the nuclear polarization enhancement
factor $\epsilon$ was mapped by varying the frequency of the applied
radiowaves. The observed enhancement factor was zero for spins in the center of
the resonant slice, was $\epsilon = +10$ to $+20$ for spins proximal to the
magnet, and was $\epsilon = -10$ to $-20$ for spins distal to the magnet. We
show that this bipolar nuclear magnetization profile is consistent with
cross-effect DNP in a $\sim \! 10^{5} \: \mathrm{T} \: \mathrm{m}^{-1}$
magnetic field gradient. Potential challenges associated with generating and
using DNP-enhanced nuclear magnetization in a nanometer-resolution magnetic
resonance imaging experiment are elucidated and discussed.",1601.07253v2
2013-09-16,Ambipolar spin transport in (111) GaAs quantum wells,"We present a microscopic theory for transport of the spin polarized charge
density wave with both electrons and holes in the $(111)$ GaAs quantum wells.
We analytically show that, contradicting to the commonly accepted belief, the
spin and charge motions are bound together only in the fully polarized system
but can be separated in the case of low spin polarization or short spin
lifetime even when the spatial profiles of spin density wave and charge density
wave overlap with each other. We further show that, the Coulomb drag between
electrons and holes can markedly enhance the hole spin diffusion if the hole
spin motion can be separated from the charge motion. In the high spin polarized
system, the Coulomb drag can boost the hole spin diffusion coefficient by more
than one order of magnitude.",1309.3871v2
2014-07-16,Spin Excitation Spectra of Spin-Orbit Coupled Bosons in Optical Lattice,"Spin-wave excitation plays important roles in the investigation of the
magnetic phases. In this paper, we study the spin-wave excitation spectra of
two-component Bose gases with spin-orbit coupling on a deep square optical
lattice using spin-wave theory. We find that, while the excitation spectrum of
the vortex crystal phase is gapless with a linear dispersion in the vicinity of
the minimum point, the spectra of the commensurate spiral spin phase and the
skyrmion crystal phase are gapped. Significantly, the spin fluctuations
strongly destabilize the classical ground state of the skyrmion phase. It
suggests the emergence of a new state in the phase diagram. Such features of
the spin excitation spectra provide further insights into the exploration of
the exotic spin phases.",1407.4172v1
2015-03-11,Spin-wave-induced spin torque in Rashba spin-orbit coupling system,"We study the effects of Rashba spin-orbit coupling on the spin torque induced
by spin waves, which are the plane wave dynamics of magnetization. The spin
torque is derived from linear response theory, and we calculate the dynamic
spin torque by considering the impurity-ladder-sum vertex corrections. This
dynamic spin torque is divided into three terms: a damping term, a $distortion$
term, and a correction term for the equation of motion. The $distorting$ torque
describes a phenomenon unique to the Rashba spin-orbit coupling system, where
the distorted motion of magnetization precession is subjected to the
anisotropic force from the Rashba coupling. The oscillation mode of the
precession exhibits an elliptical trajectory, and the ellipticity depends on
the strength of the nesting effects, which could be reduced by decreasing the
electron lifetime.",1503.03171v2
2015-11-07,Universal Spin-Momentum Locked Optical Forces,"Evanescent electromagnetic waves possess spin-momentum locking, where the
direction of propagation (momentum) is locked to the inherent polarization of
the wave (transverse spin). We study the optical forces arising from this
universal phenomenon and show that the fundamental origin of recently reported
non-trivial optical chiral forces is spin-momentum locking. For evanescent
waves, we show that the direction of energy flow, direction of decay, and
direction of spin follow a right hand rule for three different cases of total
internal reflection, surface plasmon polaritons, and $HE_{11}$ mode of an
optical fiber. Furthermore, we explain how the recently reported phenomena of
lateral optical force on chiral and achiral particles is caused by the
transverse spin of the evanescent field and the spin-momentum locking
phenomenon. Finally, we propose an experiment to identify the unique lateral
forces arising from the transverse spin in the optical fiber and point to
fundamental differences of the spin density from the well-known orbital angular
momentum of light. Our work presents a unified view on spin-momentum locking
and how it affects optical forces on chiral and achiral particles.",1511.02305v1
2018-03-30,Extraordinary SEAWs under influence of the spin-spin interaction and the quantum Bohm potential,"The separate spin evolution (SSE) of electrons causes the existence of the
spin-electron acoustic wave. Extraordinary spin-electron acoustic waves (SEAWs)
propagating perpendicular to the external magnetic field have large
contribution of the transverse electric field. Its spectrum has been studied in
the quasi-classical limit at the consideration of the separate spin evolution.
The spin-spin interaction and the quantum Bohm potential give contribution in
the spectrum extraordinary SEAW. This contribution is studied in this paper.
Moreover, it is demonstrated that the spin-spin interaction leads to the
existence of the extraordinary SEAWs if the SSE is neglected. The hybridization
of the extraordinary SEAW and the lower extraordinary wave in the regime, where
the cyclotron frequency is larger then the Langmuir frequency is studied
either.",1803.11403v1
2020-09-03,Coincidence inelastic neutron scattering for detection of two-spin magnetic correlations,"Inelastic neutron scattering (INS) is one powerful technique to study the
low-energy single-spin dynamics of magnetic materials. A variety of quantum
magnets show novel magnetic correlations such as quantum spin liquids. These
novel magnetic correlations are beyond the direct detection of INS. In this
paper we propose a coincidence technique, coincidence inelastic neutron
scattering (cINS), which can detect the two-spin magnetic correlations of the
magnetic materials. In cINS there are two neutron sources and two neutron
detectors with an additional coincidence detector. Two neutrons from the two
neutron sources are incident on the target magnetic material, and they are
scattered by the electron spins of the magnetic material. The two scattered
neutrons are detected by the two neutron detectors in coincidence with the
coincidence probability described by a two-spin Bethe-Salpeter wave function.
Since the two-spin Bethe-Salpeter wave function defines the momentum-resolved
dynamical wave function with two spins excited, cINS can explicitly detect the
two-spin magnetic correlations of the magnetic material. Thus, it can be
introduced to study the various spin valence bond states of the quantum
magnets.",2009.01680v2
2021-02-15,Emission of Spin-correlated Matter-wave Jets from Spinor Bose-Einstein Condensates,"We report the observation of matter-wave jet emission in a strongly
ferromagnetic spinor Bose-Einstein condensate of $^7$Li atoms. Directional
atomic beams with $|{F=1,m_F=1}\rangle$ and $|{F=1,m_F=-1}\rangle$ spin states
are generated from $|{F=1,m_F=0}\rangle$ state condensates, or vice versa. This
results from collective spin-mixing scattering events, where spontaneously
produced pairs of atoms with opposite momentum facilitates additional
spin-mixing collisions as they pass through the condensates. The matter-wave
jets of different spin states ($|{F=1,m_F=\pm1}\rangle$) can be a macroscopic
Einstein-Podolsky-Rosen state with spacelike separation. Its spin-momentum
correlations are studied by using the angular correlation function for each
spin state. Rotating the spin axis, the inter-spin and intra-spin momentum
correlation peaks display a high contrast oscillation, indicating collective
coherence of the atomic ensembles. We provide numerical calculations that
describe the experimental results at a quantitative level and can identify its
entanglement after 100~ms of a long time-of-flight.",2102.07613v1
2010-07-12,Quantum imaging of spin states in optical lattices,"We investigate imaging of the spatial spin distribution of atoms in optical
lattices using non-resonant light scattering. We demonstrate how scattering
spatially correlated light from the atoms can result in spin state images with
enhanced spatial resolution. Furthermore, we show how using spatially
correlated light can lead to direct measurement of the spatial correlations of
the atomic spin distribution.",1007.1899v1
2015-08-26,Calculation of Spin Observables for Proton-Proton Elastic Scattering in the Bethe-Salpeter Equation,"Bethe-Salpeter equation is applied to $p$-$p$ elastic scattering. The
observables of spin are calculated in the framework of the M matrix using the
two-body interaction potential. The parameter of the pseudovector coupling
constant is adjusted so as to reproduce the spin singlet part. It is shown that
the spin rotation $R(\theta)$ and $A(\theta)$ are improved by the resonance
effect for ${}^{\rm 1}S_{\rm 0}$.",1508.06393v1
2004-05-18,Multichannel field-effect spin barrier selector,"We have studied spin carrier dynamics under full spin-orbit coupling. The
anisotropy of dispersions for independent circular spinor polarizations is
explored as a possible vertical multichannel voltage controlled spin-filter.
Small voltage variations are found to select the current polarizations in a
resonant tunneling geometry.",0405418v1
2013-09-12,Observation of Pure Spin Transport in a Diamond Spin Wire,"Spin transport electronics - spintronics - focuses on utilizing electron spin
as a state variable for quantum and classical information processing and
storage. Some insulating materials, such as diamond, offer defect centers whose
associated spins are well-isolated from their environment giving them long
coherence times; however, spin interactions are important for transport,
entanglement, and read-out. Here, we report direct measurement of pure spin
transport - free of any charge motion - within a nanoscale quasi 1D 'spin
wire', and find a spin diffusion length ~ 700 nm. We exploit the statistical
fluctuations of a small number of spins ($\sqrt{N}$ < 100 net spins) which are
in thermal equilibrium and have no imposed polarization gradient. The spin
transport proceeds by means of magnetic dipole interactions that induce
flip-flop transitions, a mechanism that can enable highly efficient, even
reversible, pure spin currents. To further study the dynamics within the spin
wire, we implement a magnetic resonance protocol that improves spatial
resolution and provides nanoscale spectroscopic information which confirms the
observed spin transport. This spectroscopic tool opens a potential route for
spatially encoding spin information in long-lived nuclear spin states. Our
measurements probe intrinsic spin dynamics at the nanometre scale, providing
detailed insight needed for practical devices which seek to control spin.",1309.3199v3
2021-02-11,Excitation of forward and backward surface waves in a negative-index metamaterial,"We study beam transmission and refection resulting from the resonant
excitation of forward and backward surface waves in a metamaterial. We predict
that exciting these waves at an interface this medium and free space led to
transmitted and reflected beams with high amplitudes. The FDTD simulated
results demonstrate clearly propagation of these waves and their
energy-trapping ability as described by theory. The resonant coupling of the
refracted waves and reflected waves at the first interface led to the
excitation of the backward surface waves. The forward surface waves transfer
incoming energy in the direction of incidence and the backward surface transfer
incoming energy in a direction opposite to the direction of incidence (i.e.
negative direction). More also, the parameters used in these simulations were
carefully chosen to minimize the effects of interference between the incident
and the reflected beams earlier reported. In overall, these numerically
simulated results clearly demonstrate the propagation of these waves and may
serve as numerical approximations to what might be observed in experimental
setups. Putting this simply, they may find applications in optical and photonic
devices involving enhancing beam transmission and reflection using
negative-index metamaterial.",2102.06208v1
2021-10-01,Experimental quasi-1D capillary-wave turbulence,"Wave turbulence in quasi-1D geometry is usually not investigated
experimentally since low-order resonant wave interactions are theoretically
prohibited. Here, we report on the first observation of unidirectional
capillary-wave turbulence on the surface of a fluid in a canal. We also show
that five-wave interactions are the lowest-order resonant process subsisting at
small scales, and are thus probably the one generating such quasi-1D capillary
wave turbulence. We show that the wave spectrum is compatible with the
corresponding dimensional analysis prediction. The main assumptions of weak
turbulence theory are also verified experimentally. Quasi-1D wave turbulence
could be thus highlighted in other fields of wave turbulence.",2110.01448v1
2020-05-22,Dynamic diffractive resonant radiation in a linearly chirped nonlinear waveguide array,"We theoretically and numerically investigate the evolution of discrete
soliton in a 1D linearly chirped nonlinear waveguide array (WA). The discrete
soliton is self-accelerated inside the transversely chirped WA and emits a
\textit{dynamic diffractive resonant radiation} (DifRR). The radiation appears
when soliton wave-number matched with linear radiation wave. Unlike uniform WA,
the DifRR can be excited even for zero wave-number of input soliton when the
waveguide channels are chirped. The transverse modulation due to chirp
conceptually imposes a linear potential which acts as a perturbation to soliton
dynamics and leads to a monotonous wave-number shift of the propagating wave.
Exploiting perturbative variational analysis we determine the equation of
motion of soliton wave-number and use it to establish a modified phase-matching
condition which takes into account the soliton wave-number shift and
efficiently predicts the dynamic DifRR. A startling effect like generation of
dual DifRR occurs as a result of the interplay between self-accelerated soliton
and its initial wave-number. We exploit the modified phase matching relation to
understand this unique phenomenon of dual radiation and find a satisfactory
agreement with numerical result in radiation wave-number calculation.",2005.11379v1
2022-11-28,Parametric amplification of electromagnetic plasma waves in resonance with a dispersive background gravitational wave,"It is shown that a sub-luminal electromagnetic plasma wave, propagating in
phase with a background sub-luminal gravitational wave in a dispersive medium,
can undergo parametric amplification. For this phenomena to occur, the
dispersive characteristics of the two waves must properly match. The response
frequencies of the two waves (medium dependent) must lie within a definite and
restrictive range. The combined dynamics is represented by a Whitaker-Hill
equation, the quintessential model for parametric instabilities. The
exponential growth of the electromagnetic wave is displayed at the resonance;
the plasma wave grows at the expense of the background gravitational wave.
Different physical scenarios, where the phenomenon can be possible, are
discussed.",2211.15801v1
1997-03-17,Acoustic wave propagation in the solar atmosphere. IV Nonadiabatic wave excitation with frequency spectra,"We study the response of the solar atmosphere to excitations by large
amplitude acoustic waves with radiation damping now included. Monochromatic
adiabatic waves, due to unbalanced heating, generate continuously rising
chromospheric temperature plateaus in which the low frequency resonances
quickly die out. All non-adiabatic calculations lead to stable mean
chromospheric temperature distributions determined by shock dissipation and
radiative cooling. For non-adiabatic monochromatic wave excitation, a critical
frequency f_cr ~ 1/25 Hz is confirmed, which separates domains of different
resonance behaviour. For waves of frequency f < f_cr, the resonances decay,
while for waves of f > f_cr persistent resonance oscillations occur, which are
perpetuated by shock merging. Excitation with acoustic frequency spectra
produces distinct dynamical mean chromosphere models where the detailed
temperature distributions depend on the shape of the assumed spectra. The
stochasticity of the spectra and the ongoing shock merging lead to a persistent
resonance behaviour of the atmosphere. The acoustic spectra show a distinct
shape evolution with height such that at great height a pure 3 min band becomes
increasingly dominant. With our Eulerian code we did not find appreciable mass
flows at the top boundary.",9703106v1
1996-02-05,Influence of wave frequency variation on anomalous cyclotron resonance interaction of energetic electrons with finite amplitutude ducted whistler-mode wave,"The influence of wave frequency variation on the anomalous cyclotron
resonance $\omega=\omega_{Be}+kv_{\|}$ interaction (ACRI) of energetic
electrons with a ducted finite amplitude whistler-mode wave propagating through
the so-called transient plasma layer (TPL) in the magnetosphere or in the
ionosphere is studied both analytically and numerically. The anomalous
cyclotron resonance interaction takes place in the case when the whistler-mode
wave amplitude $B_{W}$ is consistent with the gradient of magnetic field
$\overrightarrow{B_0}$. The region of phase space occupied by anomalously
interacting energetic electrons (synchronous particles) is determined. The
efficiencies of both the pitch-angle scattering of resonant electrons and their
transverse acceleration are studied and the efficiencies dependence on the
magnitude and sign of the wave frequency drift is considered. It has been shown
that in the case of ACRI occuring under conditions relevant to VLF-emission in
the magnetosphere, the energy and pitch-angle changes of synchronous electrons
may be enchanced by a factor $10^2 \div 10^3$ in comparison with ones for
nonsynchronous resonant electrons. So the small in density group of synchronous
particles may give significant contribution to a whistler-mode wave damping in
TPL.",9602001v1
2016-08-04,Faraday and resonant waves in binary collisionally-inhomogeneous Bose-Einstein condensates,"We study Faraday and resonant waves in two-component quasi-one-dimensional
(cigar-shaped) collisionally inhomogeneous Bose-Einstein condensates subject to
periodic modulation of the radial confinement. We show by means of extensive
numerical simulations that, as the system exhibits stronger spatially-localised
binary collisions (whose scattering length is taken for convenience to be of
Gaussian form), the system becomes effectively a linear one. In other words, as
the scattering length approaches a delta-function, we observe that the two
nonlinear configurations typical for binary cigar-shaped condensates, namely
the segregated and the symbiotic one, turn into two overlapping Gaussian wave
functions typical for linear systems, and that the instability onset times of
the Faraday and resonant waves become longer. Moreover, our numerical
simulations show that the spatial period of the excited waves (either resonant
or Faraday ones) decreases as the inhomogeneity becomes stronger. Our results
also demonstrate that the topology of the ground state impacts the dynamics of
the ensuing density waves, and that the instability onset times of Faraday and
resonant waves, for a given level of inhomogeneity in the two-body
interactions, depend on whether the initial configuration is segregated or
symbiotic.",1608.01580v1
2021-04-16,Attenuating surface gravity waves with mechanical metamaterials,"Metamaterials and photonic/phononic crystals have been successfully developed
in recent years to achieve advanced wave manipulation and control, both in
electromagnetism and mechanics. However, the underlying concepts are yet to be
fully applied to the field of fluid dynamics and water waves. Here, we present
an example of the interaction of surface gravity waves with a mechanical
metamaterial, i.e. periodic underwater oscillating resonators. In particular,
we study a device composed by an array of periodic submerged harmonic
oscillators whose objective is to absorb wave energy and dissipate it inside
the fluid in the form of heat. The study is performed using a state of the art
direct numerical simulation of the Navier-Stokes equation in its
two-dimensional form with free boundary and moving bodies. We use a Volume of
Fluid interface technique for tracking the surface and an Immersed Boundary
method for the fluid-structure interaction. We first study the interaction of a
monochromatic wave with a single oscillator and then add up to four resonators
coupled only fluid-mechanically. We study the efficiency of the device in terms
of the total energy dissipation and find that by adding resonators, the
dissipation increases in a non trivial way. As expected, a large energy
attenuation is achieved when the wave and resonators are characterised by
similar frequencies. As the number of resonators is increased, the range of
attenuated frequencies also increases. The concept and results presented herein
are of relevance for applications in coastal protection.",2104.08243v1
2019-04-18,Particle Energy Diffusion in Linear Magnetohydrodynamic Waves,"In high-energy astronomical phenomena, the stochastic particle acceleration
by turbulences is one of the promising processes to generate non-thermal
particles. In this paper, we investigate the energy-diffusion efficiency of
relativistic particles in a temporally evolving wave ensemble that consists of
a single mode (Alfv\'en, fast or slow) of linear magnetohydrodynamic waves. In
addition to the gyroresonance with waves, the transit-time damping (TTD) also
contributes to the energy-diffusion for fast and slow-mode waves. While the
resonance condition with the TTD has been considered to be fulfilled by a very
small fraction of particles, our simulations show that a significant fraction
of particles are in the TTD resonance owing to the resonance broadening by the
mirror force, which non-resonantly diffuses the pitch angle of particles. When
the cutoff scale in the turbulence spectrum is smaller than the Larmor radius
of a particle, the gyroresonance is the main acceleration mechanism for all the
three wave modes. For the fast-mode, the coexistence of the gyroresonance and
TTD resonance leads to anomalous energy-diffusion. For a particle with its
Larmor radius smaller than the cutoff scale, the gyroresonance is negligible,
and the TTD becomes the dominant mechanism to diffuse its energy. The
energy-diffusion by the TTD-only resonance with fast-mode waves agrees with the
hard-sphere-like acceleration suggested in some high-energy astronomical
phenomena.",1904.08579v2
2019-07-18,Graded metasurface for enhanced sensing and energy harvesting,"In elastic wave systems, combining the powerful concepts of resonance and
spatial grading within structured surface arrays enable resonant metasurfaces
to exhibit broadband wave focusing, mode conversion from surface (Rayleigh)
waves to bulk (shear) waves, and spatial frequency selection. Devices built
around these concepts allow for precise control of surface waves, often with
structures that are subwavelength, and utilise rainbow trapping that separates
the signal spatially by frequency. Rainbow trapping yields large amplifications
of displacement at the resonator positions where each frequency component
accumulates. We investigate whether this amplification, and the associated
control, can be used to create energy harvesting devices; the potential
advantages and disadvantages of using graded resonant devices as energy
harvesters is considered. We concentrate upon elastic plate models for which
the A0 mode dominates, and take advantage of the large displacement amplitudes
in graded resonant arrays of rods, to design innovative metasurfaces that focus
waves for enhanced piezoelectric sensing and energy harvesting. Numerical
simulation allows us to identify the advantages of such graded metasurface
devices and quantify its efficiency, we also develop accurate models of the
phenomena and extend our analysis to that of an elastic half-space and Rayleigh
surface waves.",1907.09297v1
2012-12-19,Topological Resonances in Scattering on Networks (Graphs),"We report on a hitherto unnoticed type of resonances occurring in scattering
from networks (quantum graphs) which are due to the complex connectivity of the
graph - its topology. We consider generic open graphs and show that any cycle
leads to narrow resonances which do not fit in any of the prominent paradigms
for narrow resonances (classical barriers, localization due to disorder,
chaotic scattering). We call these resonances `topological' to emphasize their
origin in the non-trivial connectivity. Topological resonances have a clear and
unique signature which is apparent in the statistics of the resonance
parameters (such as e.g., the width, the delay time or the wave-function
intensity in the graph). We discuss this phenomenon by providing analytical
arguments supported by numerical simulation, and identify the features of the
above distributions which depend on genuine topological quantities such as the
length of the shortest cycle (girth). These signatures cannot be explained
using any of the other paradigms for narrow resonances. Finally, we propose an
experimental setting where the topological resonances could be demonstrated,
and study the stability of the relevant distribution functions to moderate
dissipation.",1212.4682v1
2013-04-15,Vibrational Resonance in the Morse Oscillator,"We investigate the occurrence of vibrational resonance in both classical and
quantum mechanical Morse oscillators driven by a biharmonic force. The
biharmonic force consists of two forces of widely different frequencies \omega
and \Omega with \Omega>>\omega. In the damped and biharmonically driven
classical Morse oscillator applying a theoretical approach we obtain an
analytical expression for the response amplitude at the low-frequency \omega.
We identify the conditions on the parameters for the occurrence of the
resonance. The system shows only one resonance and moreover at resonance the
response amplitude is 1/(d\omega) where d is the coefficient of linear damping.
When the amplitude of the high-frequency force is varied after resonance the
response amplitude does not decay to zero but approaches a nonzero limiting
value. We have observed that vibrational resonance occurs when the sinusoidal
force is replaced by a square-wave force. We also report the occurrence of
resonance and anti-resonance of transition probability of quantum mechanical
Morse oscillator in the presence of the biharmonic external field.",1304.3988v1
2014-04-29,Temporal behavior of laser induced elastic plate resonances,"This paper investigates the dependence on Poisson's ratio of local plate
resonances in low attenuating materials. In our experiments, these resonances
are generated by a pulse laser source and detected with a heterodyne
interferometer measuring surface displacement normal to the plate. The laser
impact induces a set of resonances that are dominated by Zero Group Velocity
(ZGV) Lamb modes. For some Poisson's ratio, thickness-shear resonances are also
detected. These experiments confirm that the temporal decay of ZGV modes
follows a $t^{-0.5}$ law and show that the temporal decay of the thickness
resonances is much faster. Similar decays are obtained by numerical simulations
achieved with a finite difference code. A simple model is proposed to describe
the thickness resonances. It predicts that a thickness mode decays as
$t^{-1.5}$ for large times and that the resonance amplitude is proportional to
$D^{-1.5}$ where $D$ is the curvature of the dispersion curve $\omega(k)$ at
$k=0$. This curvature depends on the order of the mode and on the Poisson's
ratio, and it explains why some thickness resonances are well detected while
others are not.",1404.7464v2
2016-06-21,On three-dimensional plasmon resonance in elastostatics,"We consider the plasmon resonance for the elastostatic system in
$\mathbb{R}^3$ associated with a very broad class of sources. The plasmonic
device takes a general core-shell-matrix form with the metamaterial located in
the shell. It is shown that the plasmonic device in the literature which
induces resonance in $\mathbb{R}^2$ does not induce resonance in
$\mathbb{R}^3$. We then construct two novel plasmonic devices with suitable
plasmon constants, varying according to the source term or the loss parameter,
which can induce resonances. If there is no core, we show that resonance always
occurs. If there is a core of an arbitrary shape, we show that the resonance
strongly depends on the location of the source. In fact, there exists a
critical radius such that resonance occurs for sources lying within the
critical radius, whereas resonance does not occur for source lying outside the
critical radius. Our argument is based on the variational technique by making
use of the primal and dual variational principles for the elastostatic system,
along with the highly technical construction of the associated perfect plasmon
elastic waves.",1606.06440v1
2019-03-05,Efficient self-resonance instability from axions,"It was recently shown that a coherent oscillation of an axion can cause an
efficient parametric resonance, leading to a prominent emission of the
gravitational waves (GWs). In this paper, conducting the Floquet analysis, we
investigate the parametric resonance instability, which potentially triggers
the emission of the GWs from axions. Such a resonance instability takes place,
when the time evolution of the background field significantly deviates from the
harmonic oscillation. Therefore, the resonance instability cannot be described
by the Mathieu equation, whose stability/instability chart is well known. In
this paper, introducing an explicitly calculable parameter $\tilde{q}$, which
can be used to classify different types of the parametric resonance described
by the general Hill's equation, we investigate the stability/instability chart
for the general Hill's equation. This can also apply to the case where the
background oscillation is anharmonic. We show that the flapping resonance
instability, which takes place for $\tilde{q}=O(1)$, typically leads to the
most significant growth of the inhomogeneous modes among the self-resonance
instability. We also investigate whether the flapping resonance takes place for
the cosine potential or not.",1903.02119v2
2019-06-30,Computing resonant modes of circular cylindrical resonators by vertical mode expansions,"Open subwavelength cylindrical resonators of finite height are widely used in
various photonics applications. Circular cylindrical resonators are
particularly important in nanophotonics, since they are relatively easy to
fabricate and can be designed to exhibit different resonance effects. In this
paper, an efficient and robust numerical method is developed for computing
resonant modes of circular cylinders which may have a few layers and may be
embedded in a layered background. The resonant modes are complex-frequency
outgoing solutions of the Maxwell's equations with no sources or incident
waves. The method uses field expansions in one-dimensional (1D) ``vertical''
modes to reduce the original three-dimensional eigenvalue problem to 1D
problems, and uses Chebyshev pseudospectral method to compute the 1D modes and
set up the discretized eigenvalue problem. In addition, a new iterative scheme
is developed so that the 1D nonlinear eigenvalue problems can be reliably
solved. For metallic cylinders, the resonant modes are calculated based on
analytic models for the dielectric functions of metals. The method is validated
by comparisons with existing numerical results, and it is also used to explore
subwavelength dielectric cylinders with high-$Q$ resonances and analyze gold
nanocylinders.",1907.00340v1
2024-03-22,Closed-channel parameters of Feshbach resonances,"In the work of Phys. Rev. A 100, 042710 (2019), it was argued that the
general description of two-body Feshbach resonances requires ""closed-channel
parameters"" related to the bare bound state causing the resonance. The present
work shows that once the resonance theory is renormalised (i.e. its parameters
are expressed in terms of physical observables) the dependence of two-body
observables on the closed-channel parameters disappears when the inter-channel
coupling is localised in a region where the wave functions are energy
independent. In such a regime, the resulting quantum defect theory is
surprisingly independent of the bare bound state energy. This result highlights
a qualitative difference between resonances in this regime, such as magnetic
resonances in ultracold atoms, and other kinds of resonances, such as hadron
resonances. Although the closed-channel parameters of magnetic resonances do
not affect two-body observables, it is suggested that they could be evidenced
experimentally from short-distance probing and three-body observables.",2403.14962v1
2006-10-11,Miscibility in a degenerate fermionic mixture induced by linear coupling,"We consider a one-dimensional mean-field-hydrodynamic model of a
two-component degenerate Fermi gas in an external trap, each component
representing a spin state of the same atom. We demonstrate that the
interconversion between them (linear coupling), imposed by a resonant
electromagnetic wave, transforms the immiscible binary gas into a miscible
state, if the coupling constant, $\kappa $, exceeds a critical value, $ \kappa
_{\mathrm{cr}}$. The effect is predicted in a variational approximation, and
confirmed by numerical solutions. Unlike the recently studied model of a binary
BEC with the linear coupling, the components in the immiscible phase of the
binary fermion mixture never fill two separated domains with a wall between
them, but rather form anti-locked ($\pi $ -phase-shifted) density waves.
Another difference from the bosonic mixture is spontaneous breaking of symmetry
between the two components in terms of numbers of atoms in them, $N_{1}$ and
$N_{2}$. The latter effect is characterized by the parameter $\nu \equiv
(N_{1}-N_{2})/(N_{1}+N_{2}) $ (only $N_{1}+N_{2}$ is a conserved quantity), the
onset of miscibility at $\kappa \geq \kappa_{\mathrm{cr}}$ meaning a transition
to $\nu \equiv 0$. At $\kappa <\kappa_{\mathrm{cr}}$, $\nu $ features damped
oscillations as a function of $\kappa $. We also briefly consider an asymmetric
model, with a chemical-potential difference between the two components.",0610317v1
2001-03-15,Late-time dynamics of rapidly rotating black holes,"We study the late-time behaviour of a dynamically perturbed rapidly rotating
black hole. Considering an extreme Kerr black hole, we show that the large
number of virtually undamped quasinormal modes (that exist for nonzero values
of the azimuthal eigenvalue m) combine in such a way that the field (as
observed at infinity) oscillates with an amplitude that decays as 1/t at late
times. This is in clear contrast with the standard late time power-law fall-off
familiar from studies of non-rotating black holes. This long-lived oscillating
``tail'' will, however, not be present for non-extreme (presumably more
astrophysically relevant) black holes, for which we find that many quasinormal
modes (individually excited to a very small amplitude) combine to give rise to
an exponentially decaying field. This result could have implications for the
detection of gravitational-wave signals from rapidly spinning black holes,
since the required theoretical templates need to be constructed from linear
combinations of many modes. Our main results are obtained analytically, but we
support the conclusions with numerical time-evolutions of the Teukolsky
equation. These time-evolutions provide an interesting insight into the notion
that the quasinormal modes can be viewed as waves trapped in the spacetime
region outside the horizon. They also suggest that a plausible mechanism for
the behaviour we observe for extreme black holes is the presence of a
``superradiance resonance cavity'' immediately outside the black hole.",0103054v1
2007-01-09,Baryon resonances in large N_c QCD,"This thesis deals with the study of baryon spectra in the context of the
$1/N_c$ expansion. The standard tool to study baryon properties is the
constituent quark model. The results are naturally model dependent. The $1/N_c$
expansion generates a new perturbative approach to QCD, convenient for low
momentum transfer. It provides a new theoretical method that is quantitative,
systematic and predictive.
  In the first part of the thesis, the $1/N_c$ expansion is introduced as well
as the baryon structure at large $N_c$. A summary of important results for
ground-state baryons is provided.
  The second part of the thesis is devoted to excited baryon states. The
symmetric orbital states are treated by analogy to the ground state. For mixed
symmetric states, two approaches are presented. The traditional one starts from
the decoupling of the wave function into an excited quark and a symmetric core.
To make the problem tractable the wave function is treated approximately,
justified by a Hartree scheme. This approach is applied to the study of the
$[{\bf 70},\ell^+] (\ell=0,2)$ multiplets (nonstrange and strange cases) and of
the $[{\bf 56},4^+]$ multiplet. An important physical result is the dependence
of the spin dependent terms of the mass operator on the excitation energy.
  Recently we suggested a new approach based on a rigorous group theoretical
treatment of the matrix elements of SU(4). No decoupling and no approximations
are necessary. When applied to the $[{\bf 70},1^-]$ nonstrange multiplet, it is
found that the leading corrections to the mass operator are of order $1/N_c$
instead of $N_c^0$, as predicted by the decoupling procedure.",0701061v1
2010-03-02,Dynamical effects of QCD in $q^2 \bar{q}^{2}$ systems,"We study the coupling of a tetraquark system to an exchanged meson-meson
channel, using a pure gluonic theory based four-quark potential {\em matrix}
model which is known to fit well a large number of data points for lattice
simulations of different geometries of a four-quark system. We find that if
this minimal-area-based potential matrix replaces the earlier used simple
Gaussian form for the gluon field overlap factor $f$ in its off-diagonal terms,
the resulting $T$-matrix and phase shifts develop an angle dependence whose
partial wave analysis reveals $D$ wave and higher angular momentum components
in it. In addition to the obvious implications of this result for the
meson-meson scattering, this new feature indicates the possibility of orbital
excitations influencing properties of meson-meson molecules through a
polarization potential. We have used a formalism of the resonating group
method, treated kinetic energy and overlap matrices on model of the potential
matrix, but decoupled the resulting complicated integral equations through the
Born approximation. In this exploratory study we have used a quadratic
confinement and not included the spin-dependence; we also used the
approximation of equal constituent quark masses.",1003.0576v5
2010-09-13,Nonlinear atom interferometer surpasses classical precision limit,"Interference is fundamental to wave dynamics and quantum mechanics. The
quantum wave properties of particles are exploited in metrology using atom
interferometers, allowing for high-precision inertia measurements [1, 2].
Furthermore, the state-of-the-art time standard is based on an interferometric
technique known as Ramsey spectroscopy. However, the precision of an
interferometer is limited by classical statistics owing to the finite number of
atoms used to deduce the quantity of interest [3]. Here we show experimentally
that the classical precision limit can be surpassed using nonlinear atom
interferometry with a Bose-Einstein condensate. Controlled interactions between
the atoms lead to non-classical entangled states within the interferometer;
this represents an alternative approach to the use of non-classical input
states [4-8]. Extending quantum interferometry [9] to the regime of large atom
number, we find that phase sensitivity is enhanced by 15 per cent relative to
that in an ideal classical measurement. Our nonlinear atomic beam splitter
follows the ""one-axis-twisting"" scheme [10] and implements interaction control
using a narrow Feshbach resonance. We perform noise tomography of the quantum
state within the interferometer and detect coherent spin squeezing with a
squeezing factor of -8.2dB [11-15]. The results provide information on the
many-particle quantum state, and imply the entanglement of 170 atoms [16].",1009.2374v1
2011-04-29,Klein tunneling in graphene: optics with massless electrons,"This article provides a pedagogical review on Klein tunneling in graphene,
i.e. the peculiar tunneling properties of two-dimensional massless Dirac
electrons. We consider two simple situations in detail: a massless Dirac
electron incident either on a potential step or on a potential barrier and use
elementary quantum wave mechanics to obtain the transmission probability. We
emphasize the connection to related phenomena in optics, such as the
Snell-Descartes law of refraction, total internal reflection, Fabry-P\'erot
resonances, negative refraction index materials (the so called meta-materials),
etc. We also stress that Klein tunneling is not a genuine quantum tunneling
effect as it does not necessarily involve passing through a classically
forbidden region via evanescent waves. A crucial role in Klein tunneling is
played by the conservation of (sublattice) pseudo-spin, which is discussed in
detail. A major consequence is the absence of backscattering at normal
incidence, of which we give a new shorten proof. The current experimental
status is also thoroughly reviewed. The appendix contains the discussion of a
one-dimensional toy model that clearly illustrates the difference in Klein
tunneling between mono- and bi-layer graphene.",1104.5632v3
2015-04-20,Experimental Observation of Bohr's Nonlinear Fluidic Surface Oscillation,"Niels Bohr in the early stage of his career developed a nonlinear theory of
fluidic surface oscillation in order to study surface tension of liquids. His
theory includes the nonlinear interaction between multipolar surface
oscillation modes, surpassing the linear theory of Rayleigh and Lamb. It
predicts a specific normalized magnitude of $0.41\dot{6}\eta^2$ for an
octapolar component, nonlinearly induced by a quadrupolar one with a magnitude
of $\eta$ much less than unity. No experimental confirmation on this prediction
has been reported. Nonetheless, accurate determination of multipolar components
is important as in optical fiber spinning, film blowing and recently in
optofluidic microcavities for ray and wave chaos studies and photonics
applications. Here, we report experimental verification of his theory. By using
optical forward diffraction, we measured the cross-sectional boundary profiles
at extreme positions of a surface-oscillating liquid column ejected from a
deformed microscopic orifice. We obtained a coefficient of $0.42\pm0.08$
consistently under various experimental conditions. We also measured the
resonance mode spectrum of a two-dimensional cavity formed by the
cross-sectional segment of the liquid jet. The observed spectra agree well with
wave calculations assuming a coefficient of $0.415\pm0.010$. Our measurements
establish the first experimental observation of Bohr's hydrodynamic theory.",1504.05105v1
2018-05-25,Cassini Ring Seismology as a Probe of Saturn's Interior I: Rigid Rotation,"Seismology of the gas giants holds the potential to resolve long-standing
questions about their internal structure and rotation state. We construct a
family of Saturn interior models constrained by the gravity field and compute
their adiabatic mode eigenfrequencies and corresponding Lindblad and vertical
resonances in Saturn's C ring, where more than twenty waves with pattern speeds
faster than the ring mean motion have been detected and characterized using
high-resolution Cassini Visual and Infrared Mapping Spectrometer (VIMS) stellar
occultation data. We present identifications of the fundamental modes of Saturn
that appear to be the origin of these observed ring waves, and use their
observed pattern speeds and azimuthal wavenumbers to estimate the bulk rotation
period of Saturn's interior to be $10{\rm h}\, 33{\rm m}\, 38{\rm s}^{+1{\rm
m}\, 52{\rm s}}_{-1{\rm m}\, 19{\rm s}}$ (median and 5%/95% quantiles),
significantly faster than Voyager and Cassini measurements of periods in
Saturn's kilometric radiation, the traditional proxy for Saturn's bulk rotation
period. The global fit does not exhibit any clear systematics indicating strong
differential rotation in Saturn's outer envelope.",1805.10286v2
2019-07-23,A photonic crystal Josephson traveling wave parametric amplifier,"An amplifier combining noise performances as close as possible to the quantum
limit with large bandwidth and high saturation power is highly desirable for
many solid state quantum technologies such as high fidelity qubit readout or
high sensitivity electron spin resonance for example. Here we introduce a new
Traveling Wave Parametric Amplifier based on Superconducting QUantum
Interference Devices. It displays a 3 GHz bandwidth, a -102 dBm 1-dB
compression point and added noise near the quantum limit. Compared to previous
state-of-the-art, it is an order of magnitude more compact, its characteristic
impedance is in-situ tunable and its fabrication process requires only two
lithography steps. The key is the engineering of a gap in the dispersion
relation of the transmission line. This is obtained using a periodic modulation
of the SQUID size, similarly to what is done with photonic crystals. Moreover,
we provide a new theoretical treatment to describe the non-trivial interplay
between non-linearity and such periodicity. Our approach provides a path to
co-integration with other quantum devices such as qubits given the low
footprint and easy fabrication of our amplifier.",1907.10158v2
2023-08-20,Nature of $X(3872)$ from its radiative decay,"We study the radiative decay of $X(3872)$ based on the assumption that
$X(3872)$ is regarded as a $c\overline{c}$ charmonium with quantum number
$J^{PC}=1^{++}$ ($J,\,P,\,C$ represent the spin, parity and charge conjugation,
respectively). The form factors of $X(3872)$ transitions to $J/\psi\gamma$ and
$\psi'\gamma$ ($\psi'$ denotes $\psi(2S)$ throughout the paper) are calculated
in the framework of the covariant light-front quark model. The phenomenological
wave function of a meson depends on the parameter $\beta$, whose inverse
essentially describes the confinement scale. In the present work, the
parameters $\beta$ for the vector $J/\psi$ and $\psi'$ mesons will be
determined through their decay constants, which are obtained from the
experimental values of their partial decay widths to the electron-positron
pair. For $X(3872)$, we determined the value of $\beta$ by the decay width of
$X(3872)\rightarrow \psi'\gamma$. Then, we examined the width of $X(3872)\to
J/\psi\gamma$ in a manner of parameter-free prediction and compared it with the
experimental value. As a result, an inconsistency or contradiction occurs
between the widths of $X(3872)\to J/\psi\gamma$ and $X(3872)\to \psi'\gamma$.
We thus conclude that $X(3872)$ cannot be a pure $c\overline c$ resonance and
that other components are necessary in its wave function.",2308.10219v2
2023-08-29,Edge Magnetoplasmon Dispersion and Time-Resolved Plasmon Transport in a Quantum Anomalous Hall Insulator,"A quantum anomalous Hall (QAH) insulator breaks reciprocity by combining
magnetic polarization and spin-orbit coupling to generate a unidirectional
transmission of signals in the absence of an external magnetic field. Such
behavior makes QAH materials a good platform for the innovation of circulator
technologies. However, it remains elusive as to how the wavelength of the
chiral edge plasmon relates to its frequency and how the plasmon wave packet is
excited in the time domain in a QAH insulator. Here, we investigate the edge
magnetoplasmon (EMP) resonances in Cr-(Bi,Sb)$_2$Te$_3$ by frequency and time
domain measurements. From disk shaped samples with various dimensions, we
obtain the dispersion relation of EMPs and extract the drift velocity of the
chiral edge state. From the time-resolved transport measurements, we identify
the velocity of the plasmon wave packet and observe a transition from the edge
to bulk transport at an elevated temperature. We show that the frequency and
time domain measurements are well modeled by loss from the microwave induced
dissipative channels in the bulk area. Our results demonstrate that the EMP
decay rate can be significantly reduced by applying a low microwave power and
fabricating devices of larger diameter $\ge100~\mu$m. In a $R=125~\mu$m sample,
a non-reciprocity of 20 dB has been realized at 1.3 GHz, shining light on using
QAH insulators to develop on-chip non-reciprocal devices.",2308.15665v1
2023-12-19,Multiband Metallic Ground State in Multilayered Nickelates La$_3$Ni$_2$O$_7$ and La$_4$Ni$_3$O$_{10}$ Probed by $^{139}$La-NMR at Ambient Pressure,"We report a $^{139}$La-NMR study of polycrystalline samples of
multi($n$)-layered nickelates, La$_3$Ni$_2$O$_{7-\delta}$ ($n=2$) and
La$_4$Ni$_3$O$_{10-\delta}$ ($n=3$), at ambient pressure. Measurements of the
nuclear magnetic resonance (NMR) spectra and nuclear spin relaxation rate
($1/T_1$) indicate the emergence of a density wave order with a gap below
$T^*\sim150$ K for La$_3$Ni$_2$O$_{7-\delta}$ and $\sim130$ K for
La$_4$Ni$_3$O$_{10-\delta}$. The finite value of $1/T_1$ below $T^*$ indicates
metallic ground states with the remaining density of states at the Fermi level
($E_{\rm F}$) under the density wave order. These features are attributed to
multiple $d$ electron bands with different characteristics. Above $T^*$, the
gradual decrease in $1/T_1T$ upon cooling implies the presence of a band with
flat dispersion near $E_{\rm F}$. From our microscopic probes, we point out
that these nickelates ($n=2$ and $3$) possess similar electronic states despite
the difference in the formal valence of the Ni-$d$ electron states, which
provides a basis for understanding the novel high-$T_{\rm c}$ superconductivity
under high pressures.",2312.11844v2
1999-01-25,Resonances in the three-neutron system,"A study of 3-body resonances has been performed in the framework of
configuration space Faddeev equations. The importance of keeping a sufficient
number of terms in the asymptotic expansion of the resonance wave function is
pointed out. We investigated three neutrons interacting in selected force
components taken from realistic nn forces.",9901074v1
2007-10-02,Nonlinear Optical Spectroscopy of Photonic Metamaterials,"We have obtained spectra of second-harmonic generation, third harmonic
generation, and four-wave mixing from a fishnet metamaterial around its
magnetic resonance. The resonant behaviors are distinctly different from those
for ordinary materials. They result from the fact that the resonance is
plasmonic, and its enhancement appears through the local field in the
nanostructure.",0710.0599v1
2009-10-29,Giant enhancement of electric field between two close metallic grains due to plasmonic resonance,"We theoretically examine plasmonic resonance between two close metallic
grains separated by a gap of width much less than the length of the incident
electromagnetic wave. Resonance conditions are established and the electric
field enhancement is found. Our general arguments are confirmed by analytic
solution of the problem for simplest geometries. We discuss an extension of our
results to more complex cases.",0910.5716v1
2010-02-04,Subharmonic resonance of global climate to solar forcing,"It is shown that, the wavelet regression detrended fluctuations of the
monthly global temperature data (land and ocean combined) for the period
1880-2009yy, are completely dominated by one-third subharmonic resonance to
annual forcing (both natural and anthropogenically induced). Role of the
oceanic Rossby waves and the resonance contribution to the El Nino phenomenon
have been discussed in detail.",1002.1024v1
2011-05-25,Counting the Resonances in High and Even Dimensional Obstacle Scattering,"In this paper, we give a polynomial lower bound for the resonances of
$-\Delta$ perturbed by an obstacle in even-dimensional Euclidean spaces,
$n\geq4$. The proof is based on a Poisson Summation Formula which comes from
the Hadamard factorization theorem in the open upper complex plane. We take
advantage of the singularity of regularized wave trace to give the
pole/resonance counting function over the principal branch of logarithmic plane
a lower bound.",1105.4972v1
2012-10-29,Resonance free regions for nontrapping manifolds with cusps,"We prove resolvent estimates for nontrapping manifolds with cusps which imply
the existence of arbitrarily wide resonance free strips, local smoothing for
the Schrodinger equation, and resonant wave expansions. We obtain lossless
limiting absorption and local smoothing estimates, but the estimates on the
holomorphically continued resolvent exhibit losses. We prove that these
estimates are optimal in certain respects.",1210.7736v1
2015-03-22,Synchrotron radiation of dissipative solitons in optical fiber cavities,"New resonant emission of dispersive waves by oscillating solitary structures
is considered analytically and numerically. The resonance condition for the
radiation is derived and it is demonstrated that the predicted resonances match
the spectral lines observed in numerical simulations perfectly. The complex
recoil of the radiation on the soliton dynamics is discussed.",1503.06405v1
2008-06-20,Slow passage through parametric resonance for a weakly nonlinear dispersive wave,"A solution of the nonlinear Klein-Gordon equation perturbed by a parametric
driver is studied. The frequency of the parametric perturbation varies slowly
and passes through a resonant value. It yields a change in a solution. We
obtain a connection formula for the asymptotic solution before and after the
resonance.",0806.3338v1
2020-06-22,Dynamics of resonances for 0th order pseudodifferential operators,"We study the dynamics of resonances of analytic perturbations of 0th order
pseudodifferential operators $P(s)$. In particular, we prove a Fermi golden
rule for resonances of $P(s)$ at embedded eigenvalues of $P=P(0)$. We also
study the dynamics of eigenvalues of $P(t)=P+it\Delta$ as the eigenvalues
converge to simple eigenvalues of $P$. The 0th order pseudodifferential
operators we consider satisfy natural dynamical assumptions and are used as
microlocal models of internal waves.",2006.11951v1
2017-10-14,Lorentz-boosted evanescent waves,"Polarization, spin, and helicity are important properties of electromagnetic
waves. It is commonly believed that helicity is invariant under the Lorentz
transformations. This is indeed so for plane waves and their localized
superpositions. However, this is not the case for evanescent waves, which are
well-defined only in a half-space, and are characterized by complex wave
vectors. Here we describe transformations of evanescent electromagnetic waves
and their polarization/spin/helicity properties under the Lorentz boosts along
the three spatial directions.",1710.05145v2
1999-07-08,Semiclassical theory of the emission properties of wave-chaotic resonant cavities,"We develop a perturbation theory for the lifetime and emission intensity for
isolated resonances in asymmetric resonant cavities. The inverse lifetime
$\Gamma$ and the emission intensity $I(\theta)$ in the open system are
expressed in terms of matrix elements of operators evaluated with eigenmodes of
the closed resonator. These matrix elements are calculated in a semiclassical
approximation which allows us to represent $\Gamma$ and $I(\theta)$ as sums
over the contributions of rays which escape the resonator by refraction.",9907109v1
2001-03-16,Dispersoin of the πresonance,"We study the dispersion of the $\pi$ resonance in the superconducting state
within the projected SO(5) model\cite{project}. Away from the the commensurate
momentum, the propagation of the $\pi$ resonance creates phase slips in the
superconducting order parameter. This frustration effect leads to a strong
dressing of the $\pi$ resonance and a downwards dispersion away from the
commensurate wave vector. Based on these results, we argue that the the
commensurate resonance and incommensurate magnetic fluctuations in the cuprates
are continuously connected.",0103363v1
2005-10-12,Resonant light-light interaction in slab waveguides: angular filters and spectral hole burning,"We consider the process of low-power light scattering by optical solitons in
a slab waveguide with homogeneous and inhomogeneous refractive index core. We
observe resonant reflection (Fano resonance) as well as resonant transmission
of light by optical solitons at certain incident angles. The resonance position
can be controlled experimentally by changing the soliton intensity and the
relative frequency detuning between the soliton and the probe light beams.",0510023v1
2002-10-02,Shell model in the complex energy plane and two-particle resonances,"An implementation of the shell-model to the complex energy plane is
presented. The representation used in the method consists of bound
single-particle states, Gamow resonances and scattering waves on the complex
energy plane. Two-particle resonances are evaluated and their structure in
terms of the single-particle degreees of freedom are analysed. It is found that
two-particle resonances are mainly built upon bound states and Gamow
resonances, but the contribution of the scattering states is also important.",0210006v1
2003-10-24,Multiplet Structure of Feshbach Resonances in non-zero partial waves,"We report a unique feature of magnetic field Feshbach resonances in which
atoms collide with non-zero orbital angular momentum. P-wave ($l=1$) Feshbach
resonances are split into two components depending on the magnitude of the
resonant state's projection of orbital angular momentum onto the field axis.
This splitting is due to the magnetic dipole-dipole interaction between the
atoms and it offers a means to tune anisotropic interactions of an ultra-cold
gas of atoms. A parameterization of the resonance in terms of an effective
range expansion is given.",0310121v1
2001-11-29,Field quantization for chaotic resonators with overlapping modes,"Feshbach's projector technique is employed to quantize the electromagnetic
field in optical resonators with an arbitray number of escape channels. We find
spectrally overlapping resonator modes coupled due to the damping and noise
inflicted by the external radiation field. For wave chaotic resonators the mode
dynamics is determined by a non--Hermitean random matrix. Upon including an
amplifying medium, our dynamics of open-resonator modes may serve as a starting
point for a quantum theory of random lasing.",0111156v2
2009-02-24,A Primer on Resonances in Quantum Mechanics,"After a pedagogical introduction to the concept of resonance in classical and
quantum mechanics, some interesting applications are discussed. The subject
includes resonances occurring as one of the effects of radiative reaction, the
resonances involved in the refraction of electromagnetic waves by a medium with
a complex refractive index, and quantum decaying systems described in terms of
resonant states of the energy. Some useful mathematical approaches like the
Fourier transform, the complex scaling method and the Darboux transformation
are also reviewed.",0902.4061v1
2010-03-29,One More Tool for Understanding Resonance,"We propose the application of graphical convolution to the analysis of the
resonance phenomenon. This time-domain approach encompasses both the finally
attained periodic oscillations and the initial transient period. It also
provides interesting discussion concerning the analysis of non-sinusoidal
waves, based not on frequency analysis, but on direct consideration of
waveforms, and thus presenting an introduction to Fourier series. Further
developing the point of view of graphical convolution, we come to a new
definition of resonance in terms of time domain.",1003.5543v2
2010-11-26,Nonlinear effects in resonant layers in solar and space plasmas,"The present paper reviews recent advances in the theory of nonlinear driven
magnetohydrodynamic (MHD) waves in slow and Alfven resonant layers. Simple
estimations show that in the vicinity of resonant positions the amplitude of
variables can grow over the threshold where linear descriptions are valid.
Using the method of matched asymptotic expansions, governing equations of
dynamics inside the dissipative layer and jump conditions across the
dissipative layers are derived. These relations are essential when studying the
efficiency of resonant absorption. Nonlinearity in dissipative layers can
generate new effects, such as mean flows, which can have serious implications
on the stability and efficiency of the resonance.",1011.5786v1
2010-12-27,Quantum behaviour of a flux qubit coupled to a resonator,"We present a detailed theoretical analysis for a system of a superconducting
flux qubit coupled to a transmission line resonator. The master equation,
accounting incoherent processes for a weakly populated resonator, is
analytically solved. An electromagnetic wave transmission coefficient through
the system, which provides a tool for probing dressed states of the qubit, is
derived. We also consider a general case for the resonator with more than one
photon population and compare the results with an experiment on the
qubit-resonator system in the intermediate coupling regime, when the coupling
energy is comparable with the qubit relaxation rate.",1012.5599v1
2011-01-16,Fano resonances in magnetic metamaterials,"We study the scattering of magnetoinductive plane waves by internal
(external) capacitive (inductive) defects coupled to a one-dimensional
split-ring resonator array. We examine a number of simple defect configurations
where Fano resonances occur and study the behavior of the transmission
coefficient as a function of the controllable external parameters. We find that
for embedded capacitive defects, the addition of a small amount of coupling to
second neighbors is necessary for the occurrence of Fano resonance. For
external inductive defects, Fano resonances are commonplace, and they can be
tuned by changing the relative orientation or distance between the defect and
the SSR array.",1101.3032v2
2011-07-29,Coupling constants of the $S_{11}$ resonances to pseudoscalar mesons and octet baryons,"Coupling constants of $S_{11}(1535)$ and $S_{11}(1650)$ resonances to
meson-baryon ($\pi N$, $\eta N$, $\eta^\prime N$, $KY$) are investigated in a
chiral quark model, complemented by inclusion of five-quark components in those
resonances. The known strong decay partial widths of both resonances are well
reproduced, provided sizeable strangeness components in the relevant wave
functions. %to excellent description for the strong decays of the above two
resonances, which %cannot be reproduced very well in the traditional chiral
quark model with or without %$SU(6)\otimes O(3)$ breaking. Finally, we find
that $S_{11}(1535)$ and $S_{11}(1650)$ %couple strongly to the channels with
strangeness.",1107.5991v2
2011-11-15,Fano-like interference of plasmon resonances at a single rod-shaped nanoantenna,"Single metallic nanorods acting as half-wave antennas in the optical range
exhibit an asymmetric, multi-resonant scattering spectrum that strongly depends
on both their length and dielectric properties. Here we show that such spectral
features can be easily understood in terms of Fano-like interference between
adjacent plasmon resonances. On the basis of analytical and numerical results
for different geometries, we demonstrate that Fano resonances may appear for
such single-particle nanoantennas provided that interacting resonances overlap
in both spatial and frequency domains.",1111.3551v2
2014-10-31,Feshbach Resonances in Kerr Frequency Combs,"We show that both the power and repetition rate of a frequency comb generated
in a nonlinear ring resonator, pumped with continuous wave (cw) coherent light,
are modulated. The modulation is brought about by the interaction of the cw
background with optical pulses excited in the resonator, and occurs in
resonators with nonzero high-order chromatic dispersion and
wavelength-dependent quality factor. The modulation frequency corresponds to
the detuning of the pump frequency from the eigenfrequency of the pumped mode
in the resonator.",1410.8604v1
2018-06-06,Nonlinear resonances generate large-scale vortices in the phase space in plasma systems,"It is well-known that the resonance phenomena can destroy the adiabatic
invariance and cause chaos and mixing. In the present paper we show that the
nonlinear wave-particle resonant interaction may cause the emergence of
large-scale coherent structures in the phase space. The combined action of the
drift due to nonlinear scattering on resonance and trapping (capture) into
resonance create a vortex-like structure, where the areas of particle
acceleration and deceleration are macroscopically separated. At the same time,
nonlinear scattering also creates a diffusion that causes mixing and
uniformization in around the vortex.",1806.02240v1
2016-12-28,Theory of adiabatic fountain resonance,"The theory of ""Adiabatic Fountain Resonance"" with superfluid $^4$He is
clarified. In this geometry a film region between two silicon wafers bonded at
their outer edge opens up to a central region with a free surface. We find that
the resonance in this system is not a Helmholtz resonance as claimed by
Gasparini and co-workers, but in fact is a fourth sound resonance. We postulate
that it occurs at relatively low frequency because the thin silicon wafers flex
appreciably from the pressure oscillations of the sound wave.",1612.08797v1
2004-05-26,Dissociation of ultracold molecules with Feshbach resonances,"Ultracold molecules are associated from an atomic Bose-Einstein condensate by
ramping a magnetic field across a Feshbach resonance. The reverse ramp
dissociates the molecules. The kinetic energy released in the dissociation
process is used to measure the widths of 4 Feshbach resonances in 87Rb. This
method to determine the width works remarkably well for narrow resonances even
in the presence of significant magnetic-field noise. In addition, a
quasi-mono-energetic atomic wave is created by jumping the magnetic field
across the Feshbach resonance.",0405606v2
2023-11-22,A blueprint for truncation resonance placement in elastic periodic lattices with unit cell asymmetry,"Elastic periodic lattices act as mechanical filters of incident vibrational
loads. By and large, they forbid wave propagation within bandgaps and resonate
outside them. However, they often encounter `truncation resonances' inside
bandgaps when certain conditions are met. This study provides an
all-encompassing blueprint for the design and selective placement of truncation
resonances in elastic periodic lattices, integrating all factors that play a
role in the onset of truncation resonances and shaping the finite lattice's
response, from unit cell configuration, mass and stiffness contrasts, to types
and symmetry of boundary conditions.",2311.13698v1
2024-02-09,"Radiative neutron capture rate of $^{11}$B$(n,γ)^{12}$B reaction from the Coulomb dissociation of $^{12}$B","We calculate the $^{11}$B$(n,\gamma)^{12}$B reaction rate, an important
constituent in nucleosynthesis networks, contributed by resonant as well as
non-resonant capture. For the resonant rate, we use the narrow resonance
approximation whereas the non-resonant contribution is calculated with the
Coulomb dissociation method for which we use finite-range distorted wave Born
approximation theory. We then compare our calculated rate of
$^{11}$B$(n,\gamma)^{12}$B reaction with those reported earlier and with other
charged particle reactions on $^{11}$B.",2402.06755v1
2016-06-15,Coupling a single electron spin to a microwave resonator: Controlling transverse and longitudinal couplings,"Microwave-frequency superconducting resonators are ideally suited to perform
dispersive qubit readout, to mediate two-qubit gates, and to shuttle states
between distant quantum systems. A prerequisite for these applications is a
strong qubit-resonator coupling. Strong coupling between an electron-spin qubit
and a microwave resonator can be achieved by correlating spin- and orbital
degrees of freedom. This correlation can be achieved through the Zeeman
coupling of a single electron in a double quantum dot to a spatially
inhomogeneous magnetic field generated by a nearby nanomagnet. In this paper,
we consider such a device and estimate spin-resonator couplings of order ~ 1
MHz with realistic parameters. Further, through realistic simulations, we show
that precise placement of the double dot relative to the nanomagnet allows to
select between a purely longitudinal coupling (commuting with the bare spin
Hamiltonian) and a purely transverse (spin non-conserving) coupling.
Additionally, we suggest methods to mitigate dephasing and relaxation channels
that are introduced in this coupling scheme. This analysis gives a clear route
toward the realization of coherent state transfer between a microwave resonator
and a single electron spin in a GaAs double quantum dot with a fidelity above
90%. Improved dynamical decoupling sequences, low-noise environments, and
longer-lived microwave cavity modes may lead to substantially higher fidelities
in the near future.",1606.04736v3
2000-11-10,Detection of Single Spin Decoherence in a Quantum Dot via Charge Currents,"We consider a quantum dot attached to leads in the Coulomb blockade regime
which has a spin 1/2 ground state. We show that by applying an ESR field to the
dot-spin the stationary current in the sequential tunneling regime exhibits a
resonance whose line width is determined by the single-spin decoherence time
T_2. The Rabi oscillations of the dot-spin are shown to induce coherent current
oscillations from which T_2 can be deduced in the time domain. We describe a
spin-inverter which can be used to pump current through a double-dot via spin
flips generated by ESR.",0011193v1
2003-09-02,Nuclear spin induced oscillatory current in spin-blocked quantum dots,"Hyperfine coupling of electron spins to nuclear spins is studied for a
GaAs-based double quantum dot in the spin blockade regime where the electron
conduction is mostly blocked by Pauli effect unless the electron spin state in
the double dot is changed. A current flowing through the double dot shows
time-dependent oscillations with a period of as long as 200 sec in a certain DC
magnetic field range. The oscillatory behavior is significantly diminished by
application of an AC magnetic field whose frequency can induce nuclear magnetic
resonance for 71Ga and 69Ga, respectively. A possible nuclear spin polarization
mechanism due to hyperfine flip-flop scattering is proposed.",0309062v1
2003-10-09,Optically-Induced Suppression of Spin Relaxation in Two-Dimensional Electron Systems with Rashba Interaction,"A pulsed technique for electrons in 2D systems, in some ways analogous to
spin echo in nuclear magnetic resonance, is discussed. We show that a sequence
of optical below-band gap pulses can be used to suppress the electron spin
relaxation due to the D'yakonov-Perel' spin relaxation mechanism. The spin
relaxation time is calculated for several pulse sequences within a Monte Carlo
simulation scheme. The maximum of spin relaxation time as a function of
magnitude/width of the pulses corresponds to $\pi$-pulse. It is important that
even relatively distant pulses efficiently suppress spin relaxation.",0310225v2
2004-06-16,Magnetic field effects on spin relaxation in heterostructures,"Effect of magnetic field on electron spin relaxation in quantum wells is
studied theoretically. We have shown that Larmor effect and cyclotron motion of
carriers can either jointly suppress D'yakonov-Perel' spin relaxation or
compensate each other. The spin relaxation rates tensor is derived for any
given direction of the external field and arbitrary ratio of bulk and
structural contributions to spin splitting. Our results are applied to the
experiments on electron spin resonance in SiGe heterostructures, and enable us
to extract spin splitting value for such quantum wells.",0406352v1
2004-07-14,Quantum Mechanics of Spin Transfer in Ferromagnetic Multilayers,"We use a quantum mechanical treatment of a ballistic spin current to describe
novel aspects of spin transfer to a ferromagnetic multilayer. We demonstrate
quantum phenomena from spin transmission resonance (STR) to magnetoelectric
spin echo (MESE), depending on the coupling between the magnetic moments in the
ferromagnetic thin films. Our calculation reveals new channels through which
the zero spin transfer occurs in multilayers: the STR and MESE. We also
illustrate that counter-intuitively, a negative spin torque can act initially
on the second moment in a bilayer system.",0407365v1
2005-12-13,Knight Field Enabled Nuclear Spin Polarization in Single Quantum Dots,"We demonstrate dynamical nuclear spin polarization in the absence of an
external magnetic field, by resonant circularly polarized optical excitation of
a single electron or hole charged quantum dot. Optical pumping of the electron
spin induces an effective inhomogeneous magnetic (Knight) field that determines
the direction along which nuclear spins could polarize and enables nuclear-spin
cooling by suppressing depolarization induced by nuclear dipole-dipole
interactions. Our observations suggest a new mechanism for spin-polarization
where spin exchange with an electron reservoir plays a crucial role. These
experiments constitute a first step towards quantum measurement of the
Overhauser field.",0512269v1
2006-09-05,Electrical detection of spin pumping due to the precessing magnetization of a single ferromagnet,"We report direct electrical detection of spin pumping, using a lateral normal
metal/ferromagnet/normal metal device, where a single ferromagnet in
ferromagnetic resonance pumps spin polarized electrons into the normal metal,
resulting in spin accumulation. The resulting backflow of spin current into the
ferromagnet generates a d.c. voltage due to the spin dependent conductivities
of the ferromagnet. By comparing different contact materials (Al and /or Pt),
we find, in agreement with theory, that the spin related properties of the
normal metal dictate the magnitude of the d.c. voltage.",0609089v1
2006-09-12,Nonlinear dynamics of quantum dot nuclear spins,"We report manifestly nonlinear dependence of quantum dot nuclear spin
polarization on applied magnetic fields. Resonant absorption and emission of
circularly polarized radiation pumps the resident quantum dot electron spin,
which in turn leads to nuclear spin polarization due to hyperfine interaction.
We observe that the resulting Overhauser field exhibits hysteresis as a
function of the external magnetic field. This hysteresis is a consequence of
the feedback of the Overhauser field on the nuclear spin cooling rate. A
semi-classical model describing the coupled nuclear and electron spin dynamics
successfully explains the observed hysteresis but leaves open questions for the
low field behaviour of the nuclear spin polarization.",0609291v1
2007-06-11,Electron and hole spin dynamics and decoherence in quantum dots,"In this article we review our work on the dynamics and decoherence of
electron and hole spins in single and double quantum dots. The first part, on
electron spins, focuses on decoherence induced via the hyperfine interaction
while the second part covers decoherence and relaxation of heavy-hole spins due
to spin-orbit interaction as well as the manipulation of heavy-hole spin using
electric dipole spin resonance.",0706.1514v1
2009-07-02,Theory of frequency-dependent spin current noise through correlated quantum dots,"We analyze the equilibrium and non-equilibrium frequency-dependent spin
current noise and spin conductance through a quantum dot in the local moment
regime. Spin current correlations are shown to behave markedly differently from
charge correlations: Equilibrium spin cross-correlations are suppressed at
frequencies below the Kondo scale, and are characterized by a universal
function that we determine numerically for zero temperature. For asymmetrical
quantum dots dynamical spin accumulation resonance is found for frequencies of
the order of the Kondo energy. At higher temperatures surprising low-frequency
anomalies related to overall spin conservation appear.",0907.0475v2
2010-01-07,Localization of spin mixing dynamics in a spin-1 Bose-Einstein condensate,"We propose to localize spin mixing dynamics in a spin-1 Bose-Einstein
condensate by a temporal modulation of spin exchange interaction, which is
tunable with optical Feshbach resonance. Adopting techniques from coherent
control, we demonstrate the localization/freezing of spin mixing dynamics, and
the suppression of the intrinsic dynamic instability and spontaneous spin
domain formation in a ferromagnetically interacting condensate of $^{87}$Rb
atoms. This work points to a promising scheme for investigating the weak
magnetic spin dipole interaction, which is usually masked by the more dominant
spin exchange interaction.",1001.1035v2
2010-04-08,Spin detection at elevated temperatures using a driven double quantum dot,"We consider a double quantum dot in the Pauli blockade regime interacting
with a nearby single spin. We show that under microwave irradiation the average
electron occupations of the dots exhibit resonances that are sensitive to the
state of the nearby spin. The system thus acts as a spin meter for the nearby
spin. We investigate the conditions for a non-demolition read-out of the spin
and find that the meter works at temperatures comparable to the dot charging
energy and sensitivity is mainly limited by the intradot spin relaxation.",1004.1289v1
2011-06-02,Spin-dependent inertial force and spin current in accelerating systems,"The spin-dependent inertial force in an accelerating system under the
presence of electromagnetic fields is derived from the generally covariant
Dirac equation. Spin currents are evaluated by the force up to the lowest order
of the spin-orbit coupling in both ballistic and diffusive regimes. We give an
interpretation of the inertial effect of linear acceleration on an electron as
an effective electric field and show that mechanical vibration in a high
frequency resonator can create a spin current via the spin-orbit interaction
augmented by the linear acceleration.",1106.0366v1
2011-12-02,Initialization and Readout of Spin Chains for Quantum Information Transport,"Linear chains of spins acting as quantum wires are a promising approach to
achieve scalable quantum information processors. Nuclear spins in apatite
crystals provide an ideal test-bed for the experimental study of quantum
information transport, as they closely emulate a one-dimensional spin chain.
Nuclear Magnetic Resonance techniques can be used to drive the spin chain
dynamics and probe the accompanying transport mechanisms. Here we demonstrate
initialization and readout capabilities in these spin chains, even in the
absence of single-spin addressability. These control schemes enable preparing
desired states for quantum information transport and probing their evolution
under the transport Hamiltonian. We further optimize the control schemes by a
detailed analysis of $^{19}$F NMR lineshape.",1112.0459v1
2013-07-12,Observation of Longitudinal Spin Seebeck Effect with Various Transition Metal Films,"We evaluated the thermoelectric properties of longitudinal spin Seebeck
devices by using ten different transition metals (TMs). Both the intensity and
sign of spin Seebeck coefficients were noticeably dependent on the degree of
the inverse spin Hall effect and the resistivity of each TM film. Spin
dependent behaviors were also observed under ferromagnetic resonance. These
results indicate that the output of the spin Seebeck devices originates in the
spin current.",1307.3320v1
2014-10-07,Determination of intrinsic spin Hall angle in Pt,"The spin Hall angle in Pt is evaluated in Pt/NiFe bilayers by spin torque
ferromagnetic resonance (ST-FMR) measurements, and is found to increase with
increasing the NiFe thickness. To extract the intrinsic spin Hall angle in Pt
by estimating the total spin current injected into NiFe from Pt, the NiFe
thickness dependent measurements are performed and the spin diffusion in the
NiFe layer is taken into account. The intrinsic spin Hall angle of Pt is
determined to be 0.068 at room temperature, and is found to be almost constant
in the temperature range 13 - 300 K.",1410.1601v1
2017-11-20,Dynamical suppression of fluctuations in an interacting nuclear spin bath of a self-assembled quantum dot using multiple pulse nuclear magnetic resonance,"Electron spin qubit coherence in quantum dots is ultimately limited by random
nuclear spin bath fluctuations. Here we aim to eliminate this randomness by
making spin bath evolution deterministic. We introduce spin bath control
sequences, which systematically combine Hahn and solid echoes to suppress
inhomogeneous broadening and nuclear-nuclear interactions. Experiments on
self-assembled quantum dots show a five-fold increase in nuclear spin
coherence. Numerical simulations show that these sequences can be used to
suppress decoherence via qubit-qubit interaction in point defect and dopant
spin systems.",1711.07238v1
2018-08-24,"Residual spin susceptibility in the spin-triplet, orbital-singlet model","Nuclear magnetic resonance (NMR) and Knight shift measurements are critical
tools in the identification of spin-triplet superconductors. We discuss the
effects of spin orbit coupling on the Knight shift and susceptibilities for a
variety of spin triplet multi-orbital gap functions with orbital-singlet
character and compare their responses to ""traditional"" single band spin-triplet
($p_x+ip_y$) superconductors. We observe a non-negligible residual
spin-susceptibility at low temperature.",1808.08029v1
2019-02-26,Dynamic spin-charge coupling: spin Hall magnetoresistance in non-magnetic conductors,"The dynamic coupling between spin and charge currents in non-magnetic
conductors is considered. As a consequence of this coupling, the spin dynamics
is directly reflected in the electrical impedance of the sample, with a
relevant frequency scale defined by spin relaxation and spin diffusion. This
allows the observation of the electron spin resonance by purely electrical
measurements.",1902.09784v1
2021-08-13,Coupling the Higgs mode and ferromagnetic resonance in spin-split superconductors with Rashba spin-orbit coupling,"We consider the Higgs mode at nonzero momentum in superconductors and
demonstrate that in the presence of Rashba spin-orbit coupling, it couples
linearly with an external exchange field. The Higgs-spin coupling dramatically
modifies the spin susceptibility near the superconducting critical temperature
and consequently enhances the spin pumping effect in a ferromagnetic
insulator/superconductor bilayer system. We show that this effect can be
detected by measuring the magnon-induced voltage generated by the inverse spin
Hall effect.",2108.06202v2
2021-03-29,Tilting Planets During Planet Scattering,"Observational constraints on planet spin-axis has recently become possible,
and revealed a system that favors a large spin-axis misalignment, a low stellar
spin-orbit misalignment and a high eccentricity. To explain the origin of such
systems, we propose a mechanism that could tilt the planet spin-axis during
planet-planet scattering, which are natural outcomes of in-situ formation and
disk migration. Specifically, we show that spin-orbit resonances could occur
for a short time period during the scattering processes, and excite the
misalignment of the planet spin-axis. This typically leads to planets with
large spin-misalignment and a wide range of eccentricities and inclinations.",2103.15843v2
2022-11-25,Certifying entanglement of spins on surfaces using ESR-STM,"We propose a protocol to certify the presence of entanglement in artificial
on-surface atomic and molecular spin arrays using electron spin resonance
carried by scanning tunnel microscopes (ESR-STM). We first generalize the
theorem that relates global spin susceptibility as an entanglement witness to
the case of anisotropic Zeeman interactions, relevant for surfaces. We then
propose a method to measure the spin susceptibilities of surface-spin arrays
combining ESR-STM with atomic manipulation. Our calculations show that
entanglement can be certified in antiferromagnetically coupled spin dimers and
trimers with state of the art ESR-STM magnetometry.",2211.14205v3
2023-01-26,Anisotropic spin-current spectroscopy of ferromagnetic superconducting gap symmetries,"We develop a microscopic theory of tunneling spin transport at the magnetic
interface between a ferromagnetic insulator and a ferromagnetic superconductor
(FSC) driven by ferromagnetic resonance. We show that the spin susceptibilities
of the FSC can be extracted from the spin currents by tuning the easy axis of
the FSC, and thus the spin currents can be a probe for the symmetries of the
spin-triplet Cooper pairing. Our results will offer a route to exploiting the
synergy of magnetism and superconductivities for spin devices.",2301.11027v3
2015-12-25,Surface spin-electron acoustic waves in magnetically ordered metals,"Degenerate plasmas with motionless ions show existence of three surface
waves: the Langmuir wave, the electromagnetic wave, and the zeroth sound.
Applying the separated spin evolution quantum hydrodynamics to half-space
plasma we demonstrate the existence of the surface spin-electron acoustic wave
(SSEAW). We study dispersion of the SSEAW. We show that there is hybridization
between the surface Langmuir wave and the SSEAW at rather small spin
polarization. In the hybridization area the dispersion branches are located
close to each other. In this area there is a strong interaction between these
waves leading to the energy exchange. Consequently, generating the Langmuir
waves with the frequencies close to hybridization area we can generate the
SSEAWs. Thus, we report a method of creation of the SEAWs.",1512.07940v1
2022-01-26,Spin Wave Electromagnetic Nano-Antenna Enabled by Tripartite Phonon-Magnon-Photon Coupling,"We investigate tripartite coupling between phonons, magnons and photons in a
periodic array of elliptical magnetostrictive nanomagnets delineated on a
piezoelectric substrate to form a two-dimensional two-phase multiferroic
crystal. A surface acoustic wave (phonons) of 5 - 35 GHz frequency launched
into the substrate causes the magnetizations of the nanomagnets to precess at
the frequency of the wave, giving rise to spin waves (magnons). The spin waves,
in turn, radiate electromagnetic waves (photons) into the surrounding space at
the surface acoustic wave frequency. Here, the phonons couple into magnons,
which then couple into photons. This tripartite phonon-magnon-photon coupling
is exploited to implement an extreme sub-wavelength electromagnetic antenna
whose measured radiation efficiency and antenna gain exceed the theoretical
limits for traditional antennas by more than two orders of magnitude at some
frequencies. Micro-magnetic simulations are in excellent agreement with
experimental observations and provide insight into the spin wave modes that
couple into radiating electromagnetic modes to implement the antenna.",2201.11110v1
2016-06-27,Nonreciprocal Transverse Photonic Spin and Magnetization-Induced Electromagnetic Spin-Orbit Coupling,"A study of nonreciprocal transverse-spin angular-momentum-density shifts for
evanescent waves in magneto-optic waveguide media is presented. Their
functional relation to electromagnetic spin- and orbital-momenta is presented
and analyzed. It is shown that the magneto-optic gyrotropy can be
re-interpreted as the nonreciprocal electromagnetic spin-density shift per unit
energy flux, thus providing an interesting alternative physical picture for the
magneto-optic gyrotropy. The transverse spin-density shift is found to be
thickness-dependent in slab optical waveguides. This dependence is traceable to
the admixture of minority helicity components in the transverse spin angular
momentum. It is also shown that the transverse spin is magnetically tunable. A
formulation of electromagnetic spin-orbit coupling in magneto-optic media is
presented, and an alternative source of spin-orbit coupling to non-paraxial
optics vortices is proposed. It is shown that magnetization-induced
electromagnetic spin-orbit coupling is possible, and that it leads to spin to
orbital angular momentum conversion in magneto-optic media evanescent waves.",1606.08334v2
2018-09-07,Spin angular momentum in planar and cylindrical waveguides induced by transverse confinement and intrinsic helicity of guided light,"In recent years, extraordinary spin angular momenta have been investigated in
a variety of structured electromagnetic waves, being of especial interest in
sub-wavelength evanescent fields. Here we demonstrate analytically that, in
planar and cylindrical waveguides supporting transverse electric/magnetic
modes, transverse spin density arises inside the waveguide (different from the
spin induced in the evanescent region outside the waveguide), carrying indeed
longitudinal extraordinary (so-called) Belinfante's spin momentum. Such
contribution depends linearly on the mode transverse wave vector, and is thus
induced by mode confinement. Cylindrical waveguides support in addition hybrid
modes that exhibit a richer phenomenology with not only azimuthal
(confinement-related) spin, but also an intrinsic helicity which leads to
longitudinal spin density and transverse helicity-dependent spin momentum.
Results are indeed presented for configurations relevant to spin-orbit coupling
in nanophotonic waveguides and to manipulating optical forces in
IR-to-microwave water-filled channels. Thus guided modes intrinsically carrying
confinement-induced transverse spin, combined with intrinsic-helicity-induced
longitudinal spin (when hybrid), hold promise of superb devices to control
spin-orbit interaction and optical forces within confined geometries throughout
the electromagnetic spectra.",1809.02406v1
2019-05-04,Skyrmion quantum spin Hall effect,"The quantum spin Hall effect is conventionally thought to require a strong
spin-orbit coupling, producing an effective spin-dependent magnetic field.
However, spin currents can also be present without transport of spins, for
example, in spin-waves or skyrmions. In this paper, we show that topological
skyrmionic spin textures can be used to realize a quantum spin Hall effect.
From basic arguments relating to the single-valuedness of the wave function, we
deduce that loop integrals of the derivative of the Hamiltonian must have a
spectrum that is integer multiples of $ 2 \pi $. By relating this to the spin
current, we form a new quantity called the quantized spin current which obeys a
precise quantization rule. This allows us to derive a quantum spin Hall effect,
which we illustrate with an example of a spin-1 Bose-Einstein condensate.",1905.01459v2
2021-06-29,Spin pumping in noncollinear antiferromagnets,"The ac spin pumping of noncollinear antiferromagnets is theoretically
investigated. Starting from an effective action description of the spin system,
we derive the Onsager coefficients connecting the spin pumping and
spin-transfer torque associated with the dynamics of the SO(3)-valued
antiferromagnetic order parameter. Our theory is applied to a kagome
antiferromagnet resonantly driven by a uniform external magnetic field. We
demonstrate that the reactive (dissipative) spin-transfer torque parameter can
be extracted from the pumped ac spin current in-phase (in quadrature) with the
driving field. Furthermore, we find that the three spin-wave bands of the
kagome AF generate spin currents with mutually orthogonal polarization
directions. This offers a unique way of controlling the spin orientation of the
pumped spin current by exciting different spin-wave modes.",2106.15187v2
2021-01-29,Comparison of Spin-Wave Modes in Connected and Disconnected Artificial Spin Ice Nanostructures Using Brillouin Light Scattering Spectroscopy,"Artificial spin ice systems have seen burgeoning interest due to their
intriguing physics and potential applications in reprogrammable memory, logic
and magnonics. Integration of artificial spin ice with functional magnonics is
a relatively recent research direction, with a host of promising results. As
the field progresses, direct in-depth comparisons of distinct artificial spin
systems are crucial to advancing the field. While studies have investigated the
effects of different lattice geometries, little comparison exists between
systems comprising continuously connected nanostructures, where spin-waves
propagate via dipole-exchange interaction, and systems with nanobars
disconnected at vertices where spin-wave propagation occurs via stray
dipolar-field. Gaining understanding of how these very different coupling
methods affect both spin-wave dynamics and magnetic reversal is key for the
field to progress and provides crucial system-design information including for
future systems containing combinations of connected and disconnected elements.
Here, we study the magnonic response of two kagome spin ices via Brillouin
light scattering, a continuously connected system and a disconnected system
with vertex gaps. We observe distinct high-frequency dynamics and magnetization
reversal regimes between the systems, with key distinctions in spin-wave
localization and mode quantization, microstate-trajectory during reversal and
internal field-profiles. These observations are pertinent for the fundamental
understanding of artificial spin systems and broader design and engineering of
reconfigurable functional magnonic crystals.",2101.12619v2
2003-02-05,Theory of the NMR relaxation rates in cuprate superconductors with field induced antiferromagnetic order,"Based on a model Hamiltonian with a d-wave pairing interaction and a
competing antiferromagnetic interaction, we numerically study the site
dependence of the nuclear spin resonance (NMR) relaxation rate T_1^{-1} as a
function of temperature for a d-wave superconductor(DSC) with magnetic field
induced spin density wave (SDW) order. In the presence of the induced SDW, we
find that there exists no simple direct relationship between NMR signal rate
T_1^{-1} and low energy local density of states while these two quantities are
linearly proportional to each other in a pure DSC. In the vortex core region,
T_1^{-1} on ^{17}O site may exhibit a double-peak behavior, one sharp and one
broad, as the temperature is increased to the superconductivity transition
temperature T_c, in contrast to a single broad peak for a pure DSC. The
existence of the sharp peak corresponds to the disappearance of the induced SDW
above a certain temperature T_{AF} which is assumed to be considerably lower
than T_c. We also show the differences between T_1^{-1} on ^{17}O and that on
^{63}Cu as a function of lattice site at different temperatures and magnetic
fields. Our results obtained from the scenario of the vortex with induced SDW
is consistent with recent NMR and scanning tunneling microscopy experiments.",0302114v1
2006-09-05,Study on N Omega-bar systems in a chiral quark model,"The N Omega-bar systems with spin S=1 and S=2 are dynamically investigated
within the framework of the chiral SU(3) quark model and the extended chiral
SU(3) quark model by solving the resonating group method (RGM) equation. The
model parameters are taken from our previous work, which gave a good
description of the energies of the baryon ground states, the binding energy of
deuteron, and the experimental data of the nucleon-nucleon (NN) and
nucleon-hyperon (NY) scattering processes. The results show that N Omega-bar
states with spin S=1 and S=2 can be bound both in the chiral SU(3) and extended
chiral SU(3) quark models, and the binding energies are about 28-59 MeV. When
the annihilation effect is considered, the binding energies increase to about
37-130 MeV, which indicates the annihilation effect plays a relatively
important role in forming an N Omega-bar bound state. At the same time, the N
Omega-bar elastic scattering processes are also studied. The S, P, D partial
wave phase shifts and the total cross sections of S=1 and S=2 channels have
been calculated by solving the RGM equation for scattering problems.",0609008v1
2007-05-29,Exotic Mott phases of the extended t--J model on the checkerboard lattice at commensurate densities,"Coulomb repulsion between electrons moving on a frustrated lattice can give
rise, at simple commensurate electronic densities, to exotic insulating phases
of matter. Such a phenomenon is illustrated using an extended t--J model on a
planar pyrochlore lattice for which the work on the quarter-filled case
[cond-mat/0702367] is complemented and extended to 1/8- and 3/8-fillings. The
location of the metal-insulator transition as a function of the Coulomb
repulsion is shown to depend strongly on the sign of the hopping. Quite
generally, the metal-insulator transition is characterized by lattice symmetry
breaking but the nature of the insulating Mott state is more complex than a
simple Charge Density Wave. Indeed, in the limit of large Coulomb repulsion,
the physics can be described in the framework of (extended) quantum
fully-packed loop or dimer models carrying extra spin degrees of freedom.
Various diagonal and off-diagonal plaquette correlation functions are computed
and the low-energy spectra are analyzed in details in order to characterize the
nature of the insulating phases. We provide evidence that, as for an electronic
density of n=1/2 (quarter-filling), the system at $n=1/4$ or $n=3/4$ exhibits
also plaquette order by forming a (lattice rotationally-invariant)
Resonating-Singlet-Pair Crystal, although with a quadrupling of the lattice
unit cell (instead of a doubling for $n=1/2$) and a 4-fold degenerate ground
state. Interestingly, qualitative differences with the bosonic analog (e.g.
known to exhibit columnar order at n=1/4) emphasize the important role of the
spin degrees of freedom in e.g. stabilizing plaquette phases w.r.t. rotational
symmetry-breaking phases.",0705.4198v1
2008-10-24,Parity doubling in the high baryon spectrum: near-degenerate three-quark quartets,"We report on the first calculation of excited baryons with a chirally
symmetric Hamiltonian, modeled after Coulomb gauge QCD (or upgraded from the
Cornell meson potential model to a field theory in all of Fock-space) showing
the insensitivity to chiral symmetry breaking. As has recently been understood,
this leads to doubling between two hadrons of equal spin and opposite parity.
As a novelty we show that three-quark, for example Delta states, group into
quartets with two states of each parity, all four states having equal angular
momentum J. Diagonalizing the chiral charge expressed in terms of quarks we
show that the quartet is slightly split into two parity doublets by the tensor
force, all splittings decreasing to zero high in the spectrum. Our specific
calculation is for the family of maximum-spin excitations of the Delta baryon.
We provide a model estimate of the experimental accuracy needed to establish
Chiral Symmetry Restoration in the high spectrum.
  We suggest that a measurement of masses of high-partial wave Delta resonances
with an accuracy of 50 MeV should be sufficient to unambiguously establish the
approximate degeneracy, and test the concept of running quark mass in the
infrared.",0810.4462v2
2009-10-23,139La NMR evidence for phase solitons in the ground state of overdoped manganites,"Hole doped transition metal oxides are famous due to their extraordinary
charge transport properties, such as high temperature superconductivity
(cuprates) and colossal magnetoresistance (manganites). Astonishing, the mother
system of these compounds is a Mott insulator, whereas important role in the
establishment of the metallic or superconducting state is played by the way
that holes are self-organized with doping. Experiments have shown that by
adding holes the insulating phase breaks into antiferromagnetic (AFM) regions,
which are separated by hole rich clumps (stripes) with a rapid change of the
phase of the background spins and orbitals. However, recent experiments in
overdoped manganites of the La(1-x)Ca(x)MnO(3) (LCMO) family have shown that
instead of charge stripes, charge in these systems is organized in a uniform
charge density wave (CDW). Besides, recent theoretical works predicted that the
ground state is inhomogeneously modulated by orbital and charge solitons, i.e.
narrow regions carrying charge (+/-)e/2, where the orbital arrangement varies
very rapidly. So far, this has been only a theoretical prediction. Here, by
using 139La Nuclear Magnetic Resonance (NMR) we provide direct evidence that
the ground state of overdoped LCMO is indeed solitonic. By lowering temperature
the narrow NMR spectra observed in the AFM phase are shown to wipe out, while
for T<30K a very broad spectrum reappears, characteristic of an incommensurate
(IC) charge and spin modulation. Remarkably, by further decreasing temperature,
a relatively narrow feature emerges from the broad IC NMR signal, manifesting
the formation of a solitonic modulation as T->0.",0910.4494v1
2009-12-11,Thermal Tides in Fluid Extrasolar Planets,"Asynchronous rotation and orbital eccentricity lead to time-dependent
irradiation of the close-in gas giant exoplanets -- the hot Jupiters. This
time-dependent surface heating gives rise to fluid motions which propagate
throughout the planet. We investigate the ability of this ""thermal tide"" to
produce a quadrupole moment which can couple to the stellar gravitational tidal
force. While previous investigations discussed planets with solid surfaces,
here we focus on entirely fluid planets in order to understand gas giants with
small cores. The Coriolis force, thermal diffusion and self-gravity of the
perturbations are ignored for simplicity. First, we examine the response to
thermal forcing through analytic solutions of the fluid equations which treat
the forcing frequency as a small parameter. In the ""equilibrium tide"" limit of
zero frequency, fluid motion is present but does not induce a quadrupole
moment. In the next approximation, finite frequency corrections to the
equilibrium tide do lead to a nonzero quadrupole moment, the sign of which
torques the planet {\it away} from synchronous spin. We then numerically solve
the boundary value problem for the thermally forced, linear response of a
planet with neutrally stratified interior and stably stratified envelope. The
numerical results find quadrupole moments in agreement with the analytic
non-resonant result at sufficiently long forcing period. Surprisingly, in the
range of forcing periods of 1-30 days, the induced quadrupole moments can be
far larger than the analytic result due to response of internal gravity waves
which propagate in the radiative envelope. We discuss the relevance of our
results for the spin, eccentricity and thermal evolution of hot Jupiters.",0912.2313v1
2011-01-02,How does a synthetic non-Abelian gauge field influence the bound states of two spin-$\half$ fermions?,"We study the bound states of two spin-$\half$ fermions interacting via a
contact attraction (characterized by a scattering length) in the singlet
channel in 3D space in presence of a uniform non-Abelian gauge field. The
configuration of the gauge field that generates a Rashba type spin-orbit
interaction is described by three coupling parameters $(\lambda_x, \lambda_y,
\lambda_z)$. For a generic gauge field configuration, the critical scattering
length required for the formation of a bound state is {\em negative}, i.e.
shifts to the ""BCS side"" of the resonance. Interestingly, we find that there
are special high-symmetry configurations (e.g., $\lambda_x = \lambda_y =
\lambda_z$) for which there is a two body bound state for {\em any} scattering
length however small and negative. Remarkably, the bound-state wave functions
obtained for such configurations have nematic spin structure similar to those
found in liquid $^3$He. Our results show that the BCS-BEC crossover is
drastically affected by the presence of a non-Abelian gauge field. We discuss
possible experimental signatures of our findings both at high and low
temperatures.",1101.0411v2
2013-10-21,"Ab initio calculations of indium arsenide in the wurtzite phase: structural, electronic and optical properties","Most III-V semiconductors, which acquire the zinc-blende phase as bulk
materials, adopt the metastable wurtzite phase when grown in the form of
nanowires. These are new semiconductors with new optical properties, in
particular, a different electronic band gap when compared with that grown in
the zinc-blende phase. The electronic gap of wurtzite InAs at the Gamma-point
of the Brillouin zone (E0 gap) has been recently measured, E0 = 0.46 eV at low
temperature. The electronic gap at the A point of the Brillouin zone
(equivalent to the L point in the zinc-blende structure, E1) has also been
obtained recently based on a resonant Raman scattering experiment. In this
work, we calculate the band structure of InAs in the zinc-blende and wurtzite
phases, using the full potential linearized augmented plane wave method,
including spin-orbit interaction. The electronic band gap has been improved
through the modified Becke-Johnson exchange-correlation potential. Both the E0
and E1 gaps agree very well with the experiment. From the calculations, a
crystal field splitting of 0.122 eV and a spin-orbit splitting of 0.312 eV (the
experimental value in zinc-blende InAs is 0.4 eV) has been obtained. Finally,
we calculate the dielectric function of InAs in both the zinc-blende and
wurtzite phases and a comparative discussion is given.",1310.5652v3
2014-11-14,Light Higgs channel of the resonant decay of magnon condensate in superfluid $^3$He-B,"In superfluids the order parameter, which describes spontaneous symmetry
breaking, is an analogue of the Higgs field in the Standard Model of particle
physics. Oscillations of the field amplitude are massive Higgs bosons, while
oscillations of the orientation are massless Nambu-Goldstone bosons. The
125~GeV Higgs boson, discovered at Large Hadron Collider, is light compared to
electroweak energy scale, which led to a suggestion of the ``little Higgs''
extension of the Standard Model, in which the light Higgs appears as a NG mode
acquiring mass due to violation of a hidden symmetry. Here we show that such
light Higgs exists in superfluid $^3$He-B, where one of three Nambu-Goldstone
spin-wave modes acquires small mass due to the spin-orbit interaction. Other
modes become optical and acoustic magnons. We observe parametric decay of
Bose-Einstein condensate of optical magnons to light Higgs modes and decay of
optical to acoustic magnons. Formation of a light Higgs from a Nambu-Goldstone
mode observed in $^3$He-B opens a possibility that such scenario can be
realized in other systems, where violation of some hidden symmetry is possible,
including the Standard Model.",1411.3983v4
2015-12-31,Fermion superfluid with hybridized $s$- and $p$-wave pairings,"Ever since the pioneering work of Bardeen, Cooper and Schrieffer in the
1950s, exploring novel pairing mechanisms for fermion superfluids has become
one of the central tasks in modern physics. Here, we investigate a new type of
fermion superfluid with hybridized $s$- and $p$-wave pairings in an ultracold
spin-1/2 Fermi gas. Its occurrence is facilitated by the co-existence of
comparable $s$- and $p$-wave interactions, which is realizable in a
two-component $^{40}$K Fermi gas with close-by $s$- and $p$-wave Feshbach
resonances. The hybridized superfluid state is stable over a considerable
parameter region on the phase diagram, and can lead to intriguing patterns of
spin densities and pairing fields in momentum space. In particular, it can
induce a phase-locked $p$-wave pairing in the fermion species that has no
$p$-wave interactions. The hybridized nature of this novel superfluid can also
be confirmed by measuring the $s$-wave and $p$-wave contacts, which can be
extracted from the high-momentum tail of the momentum distribution of each spin
component. These results enrich our knowledge of pairing superfluidity in Fermi
systems, and open the avenue for achieving novel fermion superfluids with
multiple partial-wave scatterings in cold atomic gases.",1512.09313v2
2017-09-08,Observation of $^{6}$He+$t$ cluster states in $^{9}$Li,"$^{6}$He+$t$ cluster states of exited $^{9}$Li have been measured by 32.7
MeV/nucleon $^{9}$Li beams bombarding on $^{208}$Pb target. Two resonant states
are clearly observed with the excitation energies at 9.8 MeV and 12.6 MeV and
spin-parity of 3/2$^{-}$ and 7/2$^{-}$ respectively. These two states are
considered to be members of K$^{\pi}$=1/2$^{-}$ band. The spin-parity of them
are identified by the method of angular correlation analysis and verified by
the continuum discretized coupled channels (CDCC) calculation, which agrees
with the prediction of the generator coordinate method (GCM). A monopole matrix
element about 4 fm$^{2}$ for the 3/2$^{-}$ state is extracted from the
distorted wave Born approximation (DWBA) calculation. These results strongly
support the feature of clustering structure of two neutron-rich clusters in the
neutron-rich nucleus $^{9}$Li for the first time.",1709.02515v3
2017-11-27,Cavity Magnon Polaritons with Lithium Ferrite and 3D Microwave Resonators at milli-Kelvin Temperatures,"Single crystal Lithium Ferrite (LiFe) spheres of sub-mm dimension are
examined at mK temperatures, microwave frequencies and variable DC magnetic
field, for use in hybrid quantum systems and condensed matter and fundamental
physics experiments. Strong coupling regimes of the photon-magnon interaction
(cavity magnon polariton quasi-particles) were observed with coupling strength
of up to 250 MHz at 9.5 GHz (2.6\%) with magnon linewidths of order 4 MHz (with
potential improvement to sub-MHz values). We show that the photon-magnon
coupling can be significantly improved and exceed that of the widely used
Yttrium Iron Garnet crystal, due to the small unit cell of LiFe, allowing twice
more spins per unit volume. Magnon mode softening was observed at low DC fields
and combined with the normal Zeeman effect creates magnon spin wave modes that
are insensitive to first order order magnetic field fluctuations. This effect
is observed in the Kittel mode at 5.5 GHz (and another higher order mode at 6.5
GHz) with a DC magnetic field close to 0.19 Tesla. We show that if the cavity
is tuned close to this frequency, the magnon polariton particles exhibit an
enhanced range of strong coupling and insensitivity to magnetic field
fluctuations with both first order and second order insensitivity to magnetic
field as a function of frequency (double magic point clock transition), which
could potentially be exploited in cavity QED experiments.",1711.09980v2
2018-03-28,Modification of magnetic fluctuations by interfacial interactions in artificially engineered heavy-fermion superlattices,"Recent progress in the fabrication techniques of superlattices (SLs) has made
it possible to sandwich several-layer-thick block layers (BLs) of heavy-fermion
superconductor CeCoIn5 between conventional-metal YbCoIn5 BLs or
spin-density-wave-metal CeRhIn5 BLs of a similar thickness. However, the
magnetic state in each BL, particularly at the interface, is not yet
understood, as experimental techniques applicable to the SL system are limited.
Here, we report measurements of 59Co nuclear magnetic resonance, which is a
microscopic probe of the magnetic properties inside the target BLs. In the
CeCoIn5/YbCoIn5 SL, the low-temperature magnetic fluctuations of the CeCoIn5 BL
are weakened as expected from the Rashba spin-orbit effect. However, in the
CeCoIn5/CeRhIn5 SL, the fluctuations show an anomalous enhancement below 6 K,
highlighting the importance of the magnetic proximity effect occurring near a
magnetic-ordering temperature TN ~ 3 K of the CeRhIn5 BL. We suggest that the
magnetic properties of the BLs can be altered by the interfacial interaction,
which is an alternative route to modify the magnetic properties.",1803.10382v2
2018-06-03,Field evolution of magnons in $α$-RuCl$_3$ by high-resolution polarized terahertz spectroscopy,"The Kitaev quantum spin liquid (KSL) is a theoretically predicted state of
matter whose fractionalized quasiparticles are distinct from bosonic magnons,
the fundamental excitation in ordered magnets. The layered honeycomb
antiferromagnet $\alpha$-RuCl$_3$ is a KSL candidate material, as it can be
driven to a magnetically disordered phase by application of an in-plane
magnetic field, with $H_c \sim 7$ T. Here we report a detailed characterization
of the magnetic excitation spectrum of this material by high-resolution
time-domain terahertz (THz) spectroscopy. We observe two sharp magnon
resonances whose frequencies and amplitudes exhibit a discontinuity as a
function of applied magnetic field, as well as two broader peaks at higher
energy. Below the N\'eel temperature, we find that linear spin wave theory can
account for all of these essential features of the spectra when a
$C_3$-breaking distortion of the honeycomb lattice and the presence of
structural domains are taken into account.",1806.00855v2
2019-06-21,Prediction of hidden charm strange molecular baryon states with heavy quark spin symmetry,"We have studied the meson-baryon $S-$wave interaction, using coupled
channels, in the isoscalar hidden-charm strange sector and $J^P = 1/2^-,3/2^-$
and $5/2^-$. We impose constraints of heavy quark spin symmetry in the
interaction and obtain the non vanishing matrix elements from an extension of
the local hidden gauge approach to the charm sector. The ultraviolet
divergences are renormalized using the same meson-baryon-loops regulator
previously employed in the non-strange hidden charm sector, where a good
reproduction of the properties of the newly discovered pentaquark states is
obtained. We obtain five states of $1/2^-$, four of $3/2^-$ and one of $5/2^-$,
which could be compared in the near future with forthcoming LHCb experiments.
The $5/2^-$, three of the $3/2^-$ and another three of the $1/2^-$ resonances
are originated from isoscalar $\bar D^{(*)}\Xi_c^\prime$ and $\bar
D^{(*)}\Xi_c^*$ interactions. They should be located just few MeV below the
corresponding thresholds (4446, 4513, 4588 and 4655 MeV), and would be
SU(3)-siblings of the isospin 1/2 $\bar D^{(*)} \Sigma_c^{(*)}$ quasi-bound
states previously found, and that provided a robust theoretical description of
the $P_c(4440)$, $P_c(4457)$ and $P_c(4312)$ LHCb exotic states. The another
two $1/2^-$ and $3/2^-$ states obtained in this work are result of the $\bar
D^{(*)}\Xi_c-D^{(*)}_s\Lambda_c$ coupled-channels isoscalar interaction, are
significantly broader than the others, with widths of the order of 15 MeV,
being $\bar D^{(*)}_s\Lambda_c$ the dominant decay channel.",1906.09010v1
2020-08-26,"Investigation of the Lightest Hybrid Meson Candidate with a Coupled-Channel Analysis of $\bar{p}p$-, $π^- p$- and $ππ$-Data","A sophisticated coupled-channel analysis is presented that combines different
processes: the channels $\pi^0\pi^0\eta$, $\pi^0\eta\eta$ and $K^+K^-\pi^0$
from $\bar{p}p$ annihilations, the P- and D-wave amplitudes of the $\pi\eta$
and $\pi\eta^\prime$ systems produced in $\pi^- p$ scattering, and data from
$\pi\pi$-scattering reactions. Hence our analysis combines the data sets used
in two independent previous analyses published by the Crystal Barrel experiment
and by the JPAC group. Based on the new insights from these studies, this paper
aims at a better understanding of the spin-exotic $\pi_1$ resonances in the
light-meson sector. By utilizing the K-matrix approach and realizing the
analyticity via Chew-Mandelstam functions the amplitude of the spin-exotic wave
can be well described by a single $\pi_1$ pole for both systems, $\pi\eta$ and
$\pi\eta^\prime$. The mass and width of the $\pi_1$-pole are measured to be
$(1623 \, \pm \, 47 \, ^{+24}_{-75}\,)\, \mathrm{MeV/c}^2$ and $(455 \, \pm \,
88 \, ^{+144}_{-175}\,)\, \mathrm{MeV}$.",2008.11566v3
2016-03-06,Commensurate and incommensurate magnetic order in spin-1 chains stacked on the triangular lattice in Li$_2$NiW$_2$O$_8$,"We report thermodynamic properties, magnetic ground state, and microscopic
magnetic model of the spin-1 frustrated antiferromaget Li$_{2}$NiW$_{2}$O$_{8}$
showing successive transitions at $T_{\rm N1}\simeq 18$ K and $T_{\rm N2}\simeq
12.5$ K in zero field. Nuclear magnetic resonance and neutron diffraction
reveal collinear and commensurate magnetic order with the propagation vector
$\mathbf k=(\frac12,0,\frac12)$ below $T_{\rm N2}$. The ordered moment of 1.8
$\mu_B$ at 1.5 K is directed along $[0.89(9),-0.10(5),-0.49(6)]$ and matches
the magnetic easy axis of spin-1 Ni$^{2+}$ ions, which is determined by the
scissor-like distortion of the NiO$_6$ octahedra. Incommensurate magnetic
order, presumably of spin-density-wave type, is observed in the region between
$T_{\rm N2}$ and $T_{\rm N1}$. Density-functional band-structure calculations
put forward a three-dimensional spin lattice with spin-1 chains running along
the $[01\bar 1]$ direction and stacked on a spatially anisotropic triangular
lattice in the $ab$ plane. We show that the collinear magnetic order in
Li$_2$NiW$_2$O$_8$ is incompatible with the triangular lattice geometry and
thus driven by a pronounced easy-axis single-ion anisotropy of Ni$^{2+}$.",1603.01811v2
2016-12-20,Magnetism of PrFeAsO parent compound for iron-based superconductors: Mössbauer spectroscopy study,"Moessbauer spectroscopy measurements were performed for the temperature range
between 4.2 K and 300 K in a transmission geometry applying 14.41-keV resonant
line in 57Fe for PrFeAsO the latter being a parent compound of the iron-based
superconductors belonging to the '1111' family. It was found that an itinerant
3d magnetic order develops at about 165 K and it is accompanied by an
orthorhombic distortion of the chemical unit cell. A complete longitudinal 3d
incommensurate spin density wave (SDW) order develops at about 140 K.
Transferred hyperfine magnetic field generated by the praseodymium magnetic
order on iron nuclei is seen at 12.8 K and below, i.e., below magnetic order of
praseodymium magnetic moments. It is oriented perpendicular to the field of SDW
on iron nuclei. The shape of SDW is almost rectangular at low temperatures and
it transforms into roughly triangular form around 'nematic' transition at about
140 K. Praseodymium magnetic order leads to the substantial enhancement of SDW
due to the large orbital contribution to the magnetic moment of praseodymium. A
transferred field indicates presence of strong magnetic susceptibility
anisotropy in the [b-c] plane while following rotation of praseodymium magnetic
moments in this plane with lowering temperature. It was found that 'nematic'
phase region is a region of incoherent spin density wavelets typical for a
critical region.",1612.06776v3
2019-09-17,Dynamics of a periodic $XY$ chain coupled to a photon mode,"We study the real-time dynamics of a periodic $XY$ system exposed to a
composite field comprised of a constant homogeneous magnetic and a quantized
circularly polarized electromagnetic fields. The interaction between the
quantized mode and spin-magnetic moments is modeled by the Dicke Hamiltonian.
The rotating wave approximation is applied and the conditions for its validity
are discussed. It is shown that if initially all of the excitations are
contained in the field, then in the regime of large detuning, the main
evolutionary effect involves oscillations of the excitations between the
zero-momentum modes of the chain and the field. Accordingly, the reduced photon
number and magnetization per site reveal a sort of oscillatory behavior.
Effective Hamiltonians describing the short-time dynamics of the present model
for small number of excitations and large detuning are introduced. The
resonance case is considered in the context of photon emission from the chain
initially prepared in the (partially) excited state. In particular, it is
demonstrated, in the framework of a specific example, that the superradiant
behavior shows up at the beginning of the emission, when we have an initial
state with a maximally excited $XY$ chain. Possible applications of the model
to problems such as spin chain and $J$-aggregate in a single-mode cavity are
discussed.",1909.07666v2
2020-05-09,Observation of interaction induced blockade and local spin freezing in a NMR quantum simulator,"We experimentally emulate interaction induced blockade and local spin
freezing in two and three qubit Nuclear Magnetic Resonance (NMR) architecture.
These phenomena are identical to the Rydberg blockade and Rydberg biased
freezing. In Rydberg blockade, the simultaneous excitation of two or more atoms
is blocked due to the level shift induced by the strong Van der Waal's
interaction. In such a strong interaction regime, one can also observe Rydberg
biased freezing, wherein the dynamics is confined to a subspace, with the help
of multiple drives with unequal amplitudes. Here we drive NMR qubits with
specific transition-selective radio waves, while intermittently characterizing
the quantum states via quantum state tomography. This not only allows us to
track the population dynamics, but also helps to probe quantum correlations, by
means of quantum discord, evolving under blockade and freezing phenomena.
While, our work constitutes the first experimental simulations of these
phenomena in the NMR platform, it is also the first experimental demonstration
of Rydberg biased freezing. Moreover, these studies open up interesting quantum
control perspectives in exploiting the above phenomena for entanglement
generation as well as subspace manipulations.",2005.04445v2
2020-06-07,Magnetocrystalline anisotropy of the easy-plane metallic antiferromagnet Fe$_2$As,"Magnetocrystalline anisotropy is a fundamental property of magnetic materials
that determines the dynamics of magnetic precession, the frequency of spin
waves, the thermal stability of magnetic domains, and the efficiency of
spintronic devices. We combine torque magnetometry and density functional
theory calculations to determine the magnetocrystalline anisotropy of the
metallic antiferromagnet Fe$_2$As. Fe$_2$As has a tetragonal crystal structure
with the N\'eel vector lying in the (001) plane. We report that the four-fold
magnetocrystalline anisotropy in the (001)-plane of Fe$_2$As is extremely
small, ${K_{22}} = - 150~{\rm{ J/}}{{\rm{m}}^{\rm{3}}}$ at T = 4 K, much
smaller than perpendicular magnetic anisotropy of ferromagnetic structure
widely used in spintronics device. ${K_{22}}$ is strongly temperature dependent
and close to zero at T > 150 K. The anisotropy ${K_1}$ in the (010) plane is
too large to be measured by torque magnetometry and we determine ${K_1} =
-830~{\rm{ kJ/}}{{\rm{m}}^{\rm{3}}}$ using first-principles density functional
theory. Our simulations show that the contribution to the anisotropy from
classical magnetic dipole-dipole interactions is comparable to the contribution
from spin-orbit coupling. The calculated four-fold anisotropy in the (001)
plane ${K_{22}}$ ranges from $- 292~{\rm{ J/}}{{\rm{m}}^{\rm{3}}}$ to
$280~{\rm{ J/}}{{\rm{m}}^{\rm{3}}}$, the same order of magnitude as the
measured value. We use ${K_1}$ from theory to predict the frequency and
polarization of the lowest frequency antiferromagnetic resonance mode and find
that the mode is linearly polarized in the (001)-plane with $f = $ 670 GHz.",2006.04192v1
2021-01-10,Optical magnons with dominant bond-directional exchange interactions in a honeycomb lattice iridate $α$-Li$_{2}$IrO$_{3}$,"We have used resonant inelastic x-ray scattering to reveal optical magnons in
a honeycomb lattice iridate $\alpha$-Li$_{2}$IrO$_{3}$. The spectrum in the
energy region 20-25 meV exhibits momentum dependence, of which energy is
highest at the location of the magnetic Bragg peak, ($\textit{h}, \textit{k}$)
= ($\pm$0.32, 0), and lowered toward (0, 0) and ($\pm$1, 0). We compare our
data with a linear spin-wave theory based on a generic nearest-neighbor spin
model. We find that a dominant bond-directional Kitaev interaction of order 20
meV is required to explain the energy scale observed in our study. The observed
excitations are understood as stemming from optical magnon modes whose
intensity is modulated by a structure factor, resulting in the apparent
momentum dependence. We also observed diffuse magnetic scattering arising from
the short-range magnetic correlation well above $\textit{T}_{N}$. In contrast
to Na$_{2}$IrO$_{3}$, this diffuse scattering lacks the $C_3$ rotational
symmetry of the honeycomb lattice, suggesting that the bond anisotropy is far
from negligible in $\alpha$-Li$_{2}$IrO$_{3}$.",2101.03471v1
2021-05-03,Large Angle MIEZE with Extended Fourier Time,"Modulation of Intensity Emerging from Zero Effort (MIEZE) is a neutron
resonant spin echo technique which allows one to measure time correlation
scattering functions in materials by implementing radio-frequency (RF)
intensity modulation at the sample and detector. The technique avoids neutron
spin manipulation between the sample and the detector, and thus could find
applications in cases where the sample depolarizes the neutron beam. However,
the finite sample size creates a variance in path length between the locations
where scattering and detection happens, which limits the contrast in intensity
modulation that one can detect, in particular towards long correlation times or
large scattering angles. We propose a modification to the MIEZE setup that will
enable one to extend those detection limits to longer times and larger angles.
We use Monte Carlo simulations of a neutron scattering beam line to show that,
by tilting the RF flippers in the primary spectrometer with respect to the beam
direction, one can shape the wave front of the intensity modulation at the
sample to compensate for the path variance from the sample and the detector.
The simulation results indicate that this change enables one to operate a MIEZE
instrument at much increased RF frequencies, thus improving the effective
energy resolution of the technique. The simulations show that for an incident
beam with maximum divergence of 0.33$^\circ$, the maximum Fourier time can be
increased by a factor of 3.",2105.00604v1
2021-12-15,Commensurate vortex core switching in magnetic nanodisks at Gigahertz frequencies,"The development of future spintronic applications requires a thorough and
fundamental understanding of the magnetisation dynamics. Of particular interest
are magnetic nanodisks, in which the vortex state emerges as a stable spin
configuration. Here, we focus on how the vortex core polarisation can be
reversed periodically by an oscillating magnetic field, applied perpendicularly
to the disk's surface. By means of micromagnetic simulations, we demonstrate
the presence of several subharmonic switching modes, i.e., the commensurate
ratio between the switching frequency of the core and the driving frequency.
The underlying mechanism of this periodic behaviour depends on the disk
thickness. For thin disks, the core switches periodically due to resonant
excitation of radial spin wave modes, while it is due to the breathing mode in
the case of thick disks. However, overlap of both modes impedes periodic vortex
core switching. For thin disks, the threshold field amplitude required for
periodic switching can be lowered to about 30~mT by increasing the disk
diameter. For thick disks, in contrast, the minimal field is largely unaffected
by the disk diameter, as only the energy density of a central region around the
vortex core is relevant to excite the breathing mode. Our results contribute to
the understanding of the switching mechanisms in magnetic nanodisks, which are
of technological interest due to their potential in non-volatile memory
devices.",2112.08031v1
2022-05-24,Competing magnetic phases in the frustrated spin-1/2 chain compound $β$-TeVO$_4$ probed by NMR,"In frustrated spin-1/2 chains the competition between the nearest- and
next-nearest-neighbor exchange interactions leads to a rich phase diagram that
becomes even richer in the presence of perturbations in their material
realizations. These effects are still largely unexplored, so that new insight
into static and dynamic magnetism, in particular by sensitive local probes, is
highly desired. Here we present a comprehensive $^{17}$O nuclear magnetic
resonance study of $\beta$-TeVO$_4$, where the anisotropy of the main exchange
interactions and additional weak interchain exchange interactions complement
the theoretical phase diagram. Our results confirm the dynamical nature of the
intriguing spin-stripe phase that has been reported in previous studies. In
addition, we find that the magnetic order in the high-field phase, which
develops just below the magnetization saturation, is consistent with an unusual
type of spin-density-wave (SDW) order with different alignments of the magnetic
moments on the neighboring chains. This is reminiscent of the ordering in the
SDW phase, realized in the absence of the magnetic field, and is thus most
likely stabilized by magnetic anisotropy.",2205.11875v1
2022-07-15,Origin of exchange bias in [Co/Pt]ML/Fe multilayer with orthogonal magnetic anisotropies,"Magnetization reversal of soft ferromagnetic Fe layer, coupled to [Co/Pt]ML
multilayer [ML] with perpendicular magnetic anisotropy (PMA), has been studied
in-situ with an aim to understand the origin of exchange bias (EB) in
orthogonal magnetic anisotropic systems. The interface remanant state of the ML
is modified by magnetic field annealing, and the effect of the same on the soft
Fe layer is monitored using the in-situ magneto-optical Kerr effect (MOKE). A
considerable shift in the Fe layer hysteresis loop from the centre and an
unusual increase in the coercivity, similar to exchange bias phenomena, is
attributed to the exchange coupling at the [Co/Pt]ML and Fe interface. The
effect of the coupling on spin orientation at the interface is further explored
precisely by performing an isotope selective grazing incident nuclear resonance
scattering (GINRS) technique. Here, the interface selectivity is achieved by
introducing a 2 nm thick Fe57 marker between [Co/Pt]ML and Fe layers. Interface
sensitivity is further enhanced by performing measurements under the x-ray
standing wave conditions. The combined MOKE and GINRS analysis revealed the
unidirectional pinning of the Fe layer due to the net in-plane magnetic spin at
the interface caused by magnetic field annealing. Unidirectional exchange
coupling or pinning at the interface, which may be due to the formation of
asymmetrical closure domains, is found responsible for the origin of EB with an
unusual increase in coercivity.",2207.07376v2
2022-07-29,Room Temperature DNP of Diamond Powder Using Frequency Modulation,"Dynamic nuclear polarization (DNP) is a method of enhancing NMR signals via
the transfer of polarization from electron spins to nuclear spins using
on-resonance microwave (MW) irradiation. In most cases, monochromatic
continuous-wave (MCW) MW irradiation is used. Recently, several groups have
shown that the use of frequency modulation of the MW irradiation can result in
an additional increase in DNP enhancement above that obtained with MCW. The
effect of frequency modulation on the solid effect (SE) and the cross effect
(CE) has previously been studied using the stable organic radical 4-hydroxy
TEMPO (TEMPOL) at temperatures under 20 K. Here, in addition to the SE and CE,
we discuss the effect of frequency modulation on the Overhauser effect (OE) and
the truncated CE (tCE) in the room-temperature $^{13}$C-DNP of diamond powders.
We recently showed that diamond powders can exhibit multiple DNP mechanisms
simultaneously due to the heterogeneity of P1 (substitutional nitrogen)
environments within diamond crystallites. We explore the enhancement obtained
via the two most important parameters for frequency modulation 1) Modulation
frequency, $f_{m}$ (how fast the modulation frequency is varied) and 2)
Modulation amplitude, $\Delta\omega$ (the magnitude of the change in microwave
frequency) influence the enhancement obtained via each mechanism. Frequency
modulation during DNP not only allows us to improve DNP enhancement, but also
gives us a way to control which DNP mechanism is most active. By choosing the
appropriate modulation parameters, we can selectively enhance some mechanisms
while simultaneously suppressing others.",2207.14731v1
2023-07-07,Microscopic analysis of relaxation behavior in nonlinear optical conductivity of graphene,"We present here a general formulation for the interband dynamical optical
conductivity in the nonlinear regime of graphene in the presence of a quantum
bath comprising phonons and electrons. Our main focus is the relaxation
behavior of the quantum solid of graphene perturbed by an oscillatory electric
field. Considering the optical range of the frequency and a considerable amount
of the amplitude of the field, one can observe a nonlinear response by
formulating a quantum master equation of the density operator associated with
the Hamiltonian encapsulated in the form of a spin-Boson model of dissipative
quantum statistical mechanics. Mapping the valence and conduction states as the
eigenstates of the Pauli spin operators and utilizing the rotating wave
approximation to omit off-resonant terms, one can solve the rate equation for
the mean population of the conduction and valence states and the mixing matrix
elements between them. Our results reveal the nonlinear steady-state regime's
population inversion and interband coherence. It is characterized by a single
dimensionless parameter that is directly proportional to the incident field
strength and inversely proportional to the optical frequency. Our method is
also capable of calculating the nonlinear interband optical conductivity of
doped and gapped graphene at finite temperatures. The effects of different bath
spectra for phonons and electrons are examined in detail. Although our general
formulation can address a variety of nonequilibrium response of the two-band
system, it also facilitates a connection with phenomenological modeling of
nonlinear optical conductivity.",2307.03392v1
2023-11-10,A Universal Method to Generate Hyperpolarisation in Beams and Samples,"Sizable hyperpolarisation, i.e. an imbalance of the occupation numbers of
nuclear spins in a sample deviating from thermal equilibrium, is needed in
various fields of science. For example, hyperpolarised tracers are utilised in
magnetic resonance imaging in medicine (MRI) and polarised beams and targets
are employed in nuclear physics to study the spin dependence of nuclear forces.
Here we show that the quantum interference of transitions induced by radio-wave
pumping with longitudinal and radial pulses are able to produce large
polarisations at small magnetic fields. This method is easier than established
methods, theoretically understood and experimentally proven for beams of
metastable hydrogen atoms in the keV energy range. It should also work for a
variety of samples at rest. Thus, this technique opens the door for a new
generation of polarised tracers, possibly low-field MRI with better spatial
resolution or the production of polarised fuel to increase the efficiency of
fusion reactors by manipulating the involved cross sections.",2311.05976v1
2023-11-10,Comparing continuous and pulsed nitrogen-vacancy DC magnetometry in the optical-power-limited regime,"Ensembles of nitrogen-vacancy (NV) center spins in diamond offer a robust,
precise and accurate magnetic sensor. As their applications move beyond the
laboratory, practical considerations including size, complexity, and power
consumption become important. Here, we compare two commonly-employed NV
magnetometry techniques -- continuous-wave (CW) vs pulsed magnetic resonance --
in a scenario limited by total available optical power. We develop a consistent
theoretical model for the magnetic sensitivity of each protocol that
incorporates NV photophysics - in particular, including the incomplete spin
polarization associated with limited optical power; after comparing the models'
behaviour to experiments, we use them to predict the relative DC sensitivity of
CW versus pulsed operation for an optical-power-limited, shot-noise-limited NV
ensemble magnetometer. We find a $\sim 2-3 \times$ gain in sensitivity for
pulsed operation, which is significantly smaller than seen in power-unlimited,
single-NV experiments. Our results provide a resource for practical sensor
development, informing protocol choice and identifying optimal operation
regimes when optical power is constrained.",2311.06055v1
2001-02-08,New selection rules for resonant Raman scattering on quantum wires,"The bosonisation technique is used to calculate the resonant Raman spectrum
of a quantum wire with two electronic sub-bands occupied. Close to resonance,
the cross section at frequencies in the region of the inter sub-band
transitions shows distinct peaks in parallel polarisation of the incident and
scattered light that are signature of collective higher order spin density
excitations. This is in striking contrast to the conventional selection rule
for non-resonant Raman scattering according to which spin modes can appear only
in perpendicular polarisation. We predict a new selection rule for the
excitations observed near resonance, namely that, apart from charge density
excitations, only spin modes with positive group velocities can appear as peaks
in the spectra in parallel configuration close to resonance. The results are
consistent with all of the presently available experimental data.",0102144v1
2007-01-01,Contribution of spin 1/2 and 3/2 resonances to two-photon exchange effects in elastic electron-proton scattering,"We calculate contributions of hadron resonances to two-photon exchange
effects in electron-proton scattering. In addition to the nucleon and P33
resonance, the following heavier resonances are included as intermediate states
in the two-photon exchange diagrams: D13, D33, P11, S11 and S31. We show that
the corrections due to the heavier resonances are smaller that the dominant
nucleon and P33 contributions. We also find that there is a partial
cancellation between the contributions from the spin 1/2 and spin 3/2
resonances, which results in a further suppression of their aggregate
two-photon exchange effect.",0701003v2
2011-03-29,Two energy scales in the magnetic resonance spectrum of electron and hole doped pnictide superconductors,"We argue that a multiband superconductor with sign-changing gaps may have
multiple spin resonances. We calculate the RPA-based spin resonance spectra of
a pnictide superconductor by using the five band tight-binding model or
angle-resolved photoemission spectroscopy (ARPES) Fermi surface (FS) and
experimental values of superconducting (SC) gaps. The resonance spectra split
in both energy and momenta due to the effects of multiband and multiple gaps in
$s^{\pm}-$pairing; the higher energy peak appears around the commensurate
momenta due to scattering between $\alpha-$FS to $\gamma/\delta-$FS pockets.
The second resonance is incommensurate coming from $\beta-$FS to
$\gamma/\delta-$FS scatterings and its $q-$vector is doping-dependent and hence
on the FS topology. Energies of both resonances $\omega^{1,2}_{res}$ are
strongly doping dependent and are proportional to the gap amplitudes at the
contributing FSs. We also discuss the evolution of the spin excitation spectra
with various other possible gap symmetries, which may be relevant when either
both the electron pockets or both the hole pockets completely disappear.",1103.5787v1
2011-12-11,A pre-Caloris synchronous rotation for Mercury,"The planet Mercury is locked in a spin-orbit resonance where it rotates three
times about its spin axis for every two orbits about the Sun. The current
explanation for this unique state assumes that the initial rotation of this
planet was prograde and rapid, and that tidal torques decelerated the planetary
spin to this resonance. When core-mantle boundary friction is accounted for,
capture into the 3/2 resonance occurs with a 26% probability, but the most
probable outcome is capture into one of the higher-order resonances. Here we
show that if the initial rotation of Mercury were retrograde, this planet would
be captured into synchronous rotation with a 68% probability. Strong spatial
variations of the impact cratering rate would have existed at this time, and
these are shown to be consistent with the distribution of pre-Calorian impact
basins observed by Mariner 10 and MESSENGER. Escape from this highly stable
resonance is made possible by the momentum imparted by large basin-forming
impact events, and capture into the 3/2 resonance occurs subsequently under
favourable conditions.",1112.2384v1
2012-10-17,Odd parity bottom-flavored baryon resonances,"The LHCb Collaboration has recently observed two narrow baryon resonances
with beauty. Their masses and decay modes look consistent with the quark model
orbitally excited states Lambda_b(5912) and Lambda*_b(5920), with quantum
numbers J^P=1/2^- and 3/2^-, respectively. We predict the existence of these
states within a unitarized meson-baryon coupled-channel dynamical model, which
implements heavy-quark spin symmetry. Masses, quantum numbers and couplings of
these resonances to the different meson-baryon channels are obtained. We find
that the resonances Lambda^0_b(5912) and Lambda^0_b(5920) are heavy-quark spin
symmetry partners, which naturally explains their approximate mass degeneracy.
Corresponding bottom-strange baryon resonances are predicted at Xi_b(6035.4)
(J^P=1/2^-) and Xi_b(6043.3) (J^P=3/2^-). The two Lambda_b and two Xi_b
resonances complete a multiplet of SU(3)-flavor times heavy-quark spin
symmetry.",1210.4755v3
2013-04-24,Magnonlike dispersion of spin resonance in Ni-doped BaFe$_2$As$_2$,"Inelastic neutron scattering measurements on
Ba(Fe$_{0.963}$Ni$_{0.037}$)$_2$As$_2$ manifest a neutron spin resonance in the
superconducting state with anisotropic dispersion within the Fe layer. Whereas
the resonance is sharply peaked at Q$_{AFM}$ along the orthorhombic a axis, the
resonance disperses upwards away from Q$_{AFM}$ along the b axis. In contrast
to the downward dispersing resonance and hour-glass shape of the spin
excitations in superconducting cuprates, the resonance in electron-doped
BaFe$_2$As$_2$ compounds possesses a magnon-like upwards dispersion.",1304.6657v1
2014-03-11,On the disputed $π_1(1600)$ resonance and observation of a new iso-vector resonance,"The COMPASS experiment at CERN delivers new results on the search for exotic
mesons. A spin-exotic resonance, the $\pi_1(1600)$, was reported by several
experiments in the past. Those observations are, however, still to date highly
disputed in the community. Especially the $\rho\pi$ decay channel allows for
simultaneous observation of well established and less known resonances in
different decay modes. The results from amplitude analysis of diffractively
produced $(3\pi)^{-}$ final states show consistently a spin-exotic signal, that
appears in agreement with previous observations of the $\pi_1(1600)$. The
high-statistics 2008 data sample allows and demands for an extended amplitude
analysis method that further disentangles resonant and non-resonant particle
production. The present status of analysis of COMPASS data and the observation
of a new iso-vector meson $a_1(1420)$ is discussed.",1403.2667v1
2015-07-13,Coupling quantum circuits to magnetic molecular qubits,"This thesis explores the coupling of magnetic systems to quantum circuits in
the context of quantum computing applications. In particular we study the
coupling of superconducting coplanar waveguide resonators to Single Molecule
Magnets (SMMs) . The combination of approaches from the fields of Cavity
Quantum electrodynamics (QED) and Circuit QED with those from the field of
molecular magnetism con provide unique opportunities for quantum computing. We
investigate the necessary conditions for coupling single spins and spin
ensembles to resonators and what characteristics SMMs should have in order to
provide interesting alternatives as quantum bits. We present test measurements
of several magnetic samples using both broadband spectroscopy with open
waveguides and EPR spectroscopy using coplanar waveguide resonators. We also
design, fabricate, and test nanometric constrictions in superconducting
resonators with the objective of improving their coupling to single spins. We
evaluate the performance of these constricted resonators in comparison to
unmodified resonators.",1507.03579v2
2018-07-02,Tunable Nb superconducting resonators based upon a Ne-FIB-fabricated constriction nanoSQUID,"Hybrid superconducting--spin systems offer the potential to combine highly
coherent atomic quantum systems with the scalability of superconducting
circuits. To fully exploit this potential requires a high quality-factor
microwave resonator, tunable in frequency and able to operate at magnetic
fields optimal for the spin system. Such magnetic fields typically rule out
conventional Al-based Josephson junction devices that have previously been used
for tunable high-$Q$ microwave resonators. The larger critical field of niobium
(Nb) allows microwave resonators with large field resilience to be fabricated.
Here, we demonstrate how constriction-type weak links, patterned in parallel
into the central conductor of a Nb coplanar resonator using a neon focused ion
beam (FIB), can be used to implement a frequency-tunable resonator. We study
transmission through two such devices and show how they realise high quality
factor, tunable, field resilient devices which hold promise for future
applications coupling to spin systems.",1807.00582v2
2024-02-12,Spin orbit resonance cascade via core shell model. Application to Mercury and Ganymede,"We discuss a model describing the spin orbit resonance cascade. We assume
that the primary has a two-layer (core-shell) structure: it is composed by a
thin solid crust and an inner and heavier solid core that are interacting due
to the presence of a fluid interface. We assume two sources of dissipation: a
viscous one, depending on the relative angular velocity between core and crust
and a tidal one, smaller than the first, due to the viscoelastic structure of
the core. We show how these two sources of dissipation are needful for the
capture in spin-orbit resonance. The crust and the core fall in resonance with
different time scales if the viscous coupling between them is big enough.
Finally, the tidal dissipation of the viscoelastic core, decreasing the
eccentricity, brings the system out of the resonance in a third very long time
scale. This mechanism of entry and exit from resonance ends in the $1:1$ stable
state.",2402.07650v1
2005-09-06,Non-steady-state double-resonant extremely asymmetrical scattering of waves in periodic gratings,"Double-resonant extremely asymmetrical scattering (DEAS) is a strongly
resonant type of Bragg scattering in two joint or separated uniform gratings
with different phases. It is characterised by a very strong increase of the
scattered and incident wave amplitudes inside and between the gratings at a
resonant phase shift between the gratings. DEAS is realised when the first
diffracted order satisfying the Bragg condition propagates parallel to the
grating boundaries, and the joint or separated gratings interact by means of
the diffractional divergence of the scattered waves from one grating into
another. This Letter develops a theory of non-steady-state DEAS of bulk TE
electromagnetic waves in holographic gratings, and investigates the process of
relaxation of the incident and scattered wave amplitudes to their steady-state
values inside and outside the gratings. Typical relaxation times are
determined. Physical explanation of the predicted effects is presented.",0509041v1
2009-03-05,Nonlinear resonant absorption of fast magnetoacoustic waves in strongly anisotropic and dispersive plasmas,"The nonlinear theory of driven magnetohydrodynamics (MHD) waves in strongly
anisotropic and dispersive plasmas, developed for slow resonance by Clack and
Ballai [Phys. Plasmas, 15, 2310 (2008)] and Alfv\'en resonance by Clack
\emph{et al.} [A&A,494, 317 (2009)], is used to study the weakly nonlinear
interaction of fast magnetoacoustic (FMA) waves in a one-dimensional planar
plasma. The magnetic configuration consists of an inhomogeneous magnetic slab
sandwiched between two regions of semi-infinite homogeneous magnetic plasmas.
Laterally driven FMA waves penetrate the inhomogeneous slab interacting with
the localized slow or Alfv\'{e}n dissipative layer and are partly reflected,
dissipated and transmitted by this region. The nonlinearity parameter defined
by Clack and Ballai (2008) is assumed to be small and a regular perturbation
method is used to obtain analytical solutions in the slow dissipative layer.
The effect of dispersion in the slow dissipative layer is to further decrease
the coefficient of energy absorption, compared to its standard weakly nonlinear
counterpart, and the generation of higher harmonics in the outgoing wave in
addition to the fundamental one. The absorption of external drivers at the
Alfv\'{e}n resonance is described within the linear MHD with great accuracy.",0903.0948v1
2010-09-24,Spatial Damping of Propagating Kink Waves in Prominence Threads,"Transverse oscillations and propagating waves are frequently observed in
threads of solar prominences/filaments and have been interpreted as kink
magnetohydrodynamic (MHD) modes. We investigate the spatial damping of
propagating kink MHD waves in transversely nonuniform and partially ionized
prominence threads. Resonant absorption and ion-neutral collisions (Cowling's
diffusion) are the damping mechanisms taken into account. The dispersion
relation of resonant kink waves in a partially ionized magnetic flux tube is
numerically solved by considering prominence conditions. Analytical expressions
of the wavelength and damping length as functions of the kink mode frequency
are obtained in the Thin Tube and Thin Boundary approximations. For typically
reported periods of thread oscillations, resonant absorption is an efficient
mechanism for the kink mode spatial damping, while ion-neutral collisions have
a minor role. Cowling's diffusion dominates both the propagation and damping
for periods much shorter than those observed. Resonant absorption may explain
the observed spatial damping of kink waves in prominence threads. The
transverse inhomogeneity length scale of the threads can be estimated by
comparing the observed wavelengths and damping lengths with the theoretically
predicted values. However, the ignorance of the form of the density profile in
the transversely nonuniform layer introduces inaccuracies in the determination
of the inhomogeneity length scale.",1009.4871v1
2010-11-09,Surfatron acceleration of a relativistic particle by electromagnetic plane wave,"We study motion of a relativistic charged particle in a plane slow
electromagnetic wave and background uniform magnetic field. The wave propagates
normally to the background field. Under certain conditions, the resonance
between the wave and the Larmor motion of the particle is possible. Capture
into this resonance results in acceleration of the particle along the wave
front (surfatron acceleration). We analyse the phenomenon of capture and show
that a captured particle never leaves the resonance and its energy infinitely
grows. Scattering on the resonance is also studied. We find that this
scattering results in diffusive growth of the particle energy. Finally, we
estimate energy losses due to radiation by an accelerated particle.",1011.2236v1
2013-05-28,Rational solitons of wave resonant interaction models,"Integrable models of resonant interaction of two or more waves in 1+1
dimensions are known to be of applicative interest in several areas. Here we
consider a system of three coupled wave equations which includes as special
cases the vector Nonlinear Schroedinger equations and the equations describing
the resonant interaction of three waves. The Darboux-Dressing construction of
soliton solutions is applied under the condition that the solutions have
rational, or mixed rational-exponential, dependence on coordinates. Our
algebraic construction relies on the use of nilpotent matrices and their Jordan
form. We systematically search for all bounded rational (mixed
rational-exponential) solutions and find, for the first time to our knowledge,
a broad family of such solutions of the three wave resonant interaction
equations.",1305.6636v1
2013-07-12,Numerical modeling of nonlinear acoustic waves in a tube connected with Helmholtz resonators,"Acoustic wave propagation in a one-dimensional waveguide connected with
Helmholtz resonators is studied numerically. Finite amplitude waves and viscous
boundary layers are considered. The model consists of two coupled evolution
equations: a nonlinear PDE describing nonlinear acoustic waves, and a linear
ODE describing the oscillations in the Helmholtz resonators. The thermal and
viscous losses in the tube and in the necks of the resonators are modeled by
fractional derivatives. A diffusive representation is followed: the convolution
kernels are replaced by a finite number of memory variables that satisfy local
ordinary differential equations. A splitting method is then applied to the
evolution equations: their propagative part is solved using a standard TVD
scheme for hyperbolic equations, whereas their diffusive part is solved
exactly. Various strategies are examined to compute the coefficients of the
diffusive representation; finally, an optimization method is preferred to the
usual quadrature rules. The numerical model is validated by comparisons with
exact solutions. The properties of the full nonlinear solutions are
investigated numerically. In particular, the existence of acoustic solitary
waves is confirmed.",1307.3373v2
2013-07-16,TE Wave Measurement and Modeling,"In the TE wave method, microwaves are coupled into the beam-pipe and the
effect of the electron cloud on these microwaves is measured. An electron cloud
(EC) density can then be calculated from this measurement. There are two
analysis methods currently in use. The first treats the microwaves as being
transmitted from one point to another in the accelerator. The second more
recent method, treats the beam-pipe as a resonant cavity. This paper will
summarize the reasons for adopting the resonant TE wave analysis as well as
give examples from CESRTA and DA{\Phi}NE of resonant beam-pipe. The results of
bead-pull bench measurements will show some possible standing wave patterns,
including a cutoff mode (evanescent) where the field decreases exponentially
with distance from the drive point. We will outline other recent developments
in the TE wave method including VORPAL simulations of microwave resonances, as
well as the simulation of transmission in the presence of both an electron
cloud and magnetic fields.",1307.4315v1
2014-12-17,Traveling Waves and their Tails in Locally Resonant Granular Systems,"In the present study, we revisit the theme of wave propagation in locally
resonant granular crystal systems, also referred to as Mass-in-Mass systems. We
use 3 distinct approaches to identify relevant traveling waves. The first
consists of a direct solution of the traveling wave problem. The second one
consists of the solution of the Fourier tranformed variant of the problem. or,
more precisely, of its convolution reformulation (upon an inverse Fourier
transform) of the problem in real space. Finally, our third approach will
restrict considerations to a finite domain, utilizing the notion of Fourier
series for important technical reasons, namely the avoidance of resonances,
that will be discussed in detail. All three approaches can be utilized in
either the displacement or the strain formulation. Typical resulting
computations in finite domains result in the solitary waves bearing symmetric
non-vanishing tails at both ends of the computational domain. Importantly,
however, a countably infinite set of resonance conditions is identified for
which solutions with genuinely monotonic decaying tails arise.",1412.5462v1
2019-06-24,Universal mechanism of low-frequency brain rhythm formation through nonlinear coupling of high-frequency spiking-like activity,"A universal mechanism of emergence of synchronized low frequency brain wave
field activity is presented as a result of nonlinear coupling with flat
frequency neuronal forcing. The mechanism utilizes a unique dispersion
properties of weakly-evanescent wave--like brain surface modes that are
predicted to exist within a inhomogeneous and anisotropic physical brain tissue
model. These surface modes are able to propagate in thin inhomogeneous layers
with frequencies that are inverse proportional to wave numbers. The resonant
and non-resonant terms of nonlinear coupling between multiple modes produce
both synchronous spiking-like high frequency wave activity as well as low
frequency wave rhythms. The relatively narrow localized frequency response of
the non-resonant coupling can be expressed by terms similar to phase coupling
in oscillatory systems. Numerical simulation of forced multiple mode dynamics
shows as forcing increases a transition from damped to oscillatory regime that
is then silenced off as over excitation is reached. The resonant nonlinear
coupling results in emergence of low frequency rhythms with frequencies that
are several orders of magnitude below the linear frequencies of modes taking
part in the coupling.",1906.09716v1
2021-04-16,High-quality level-crossing resonances under counterpropagating circularly polarized light waves for applications in atomic magnetometry,"Level-crossing (LC) resonances in a buffer-gas-filled cesium vapor cell are
studied under counterpropagating pump and probe light waves with opposite
circular polarizations. The waves excite the D$_1$-line ground-state level
$F_g$$=\,$$4$, while a transverse magnetic field (${\rm B}_x$$\perp$${\rm k}$)
is scanned around zero to observe the resonance of electromagnetically induced
absorption (EIA). It is shown that adding the pump light wave significantly
improves the properties of the resonances in comparison with the commonly used
scheme with a single light wave. As far as a small vapor cell ($\approx\,$0.1
cm$^3$) at relatively low temperature ($\approx\,$45-60$\,^\circ$C) is
utilized, the results have good prospects for developing a low-power
miniaturized atomic magnetometer.",2104.08192v1
2019-09-10,Faraday and Resonant Waves in Dipolar Cigar-Shaped Bose-Einstein Condensates,"Faraday and resonant density waves emerge in Bose-Einstein condensates as a
result of harmonic driving of the system. They represent nonlinear excitations
and are generated due to the interaction-induced coupling of collective
oscillation modes and the existence of parametric resonances. Using a
mean-field variational and a full numerical approach, we studied density waves
in dipolar condensates at zero temperature, where breaking of the symmetry due
to anisotropy of the dipole-dipole interaction (DDI) plays an important role.
We derived variational equations of motion for the dynamics of a driven dipolar
system and identify the most unstable modes that correspond to the Faraday and
resonant waves. Based on this, we derived the analytical expressions for
spatial periods of both types of density waves as functions of the contact and
the DDI strength. We compared the obtained variational results with the results
of extensive numerical simulations that solve the dipolar Gross-Pitaevskii
equation in 3D, and found a very good agreement.",1909.04637v1
2020-07-20,Surface wave non-reciprocity via time-modulated metamaterials,"We investigate how Rayleigh waves interact with modulated resonators located
on the free surface of a semi-infinite elastic medium. We begin by studying the
dynamics of a single resonator with time-modulated stiffness. In particular, we
evaluate the accuracy of an analytical approximation of the resonator response
and identify the parameter ranges in which its behavior remains stable. Then,
we develop an analytical model to describe the interaction between surface
waves and an array of resonators with spatio-temporally modulated stiffness. By
combining our analytical models with full-scale numerical simulations, we
demonstrate that spatio-temporal stiffness modulation of this elastic
metasurface leads to the emergence of non-reciprocal features in the Rayleigh
wave spectrum. Specifically, we show how the frequency content of a propagating
signal can be filtered and converted when traveling through the modulated
medium, and illustrate how surface-to-bulk wave conversion plays a role in
these phenomena. Throughout this article, we indicate bounds of modulation
parameters for which our theory is reliable, thus providing guidelines for
future experimental studies on the topic.",2007.10531v2
2021-06-24,Landau damping of electron-acoustic waves due to multi-plasmon resonances,"The linear and nonlinear theories of electron-acoustic waves (EAWs) are
studied in a partially degenerate quantum plasma with two-temperature electrons
and stationary ions. The initial equilibrium of electrons is assumed to be
given by the Fermi-Dirac distribution at finite temperature. By employing the
multi-scale asymptotic expansion technique to the one-dimensional Wigner-Moyal
and Poisson equations, it is shown that the effects of multi-plasmon resonances
lead to a modified complex Korteweg-de Vries (KdV) equation with a new nonlocal
nonlinearity. Besides giving rise to a nonlocal nonlinear term, the
wave-particle resonance also modifies the local nonlinear coupling coefficient
of the KdV equation. The latter is shown to conserve the number of particles,
however, the wave energy decays with time. A careful analysis shows that the
two-plasmon resonance is the dominant mechanism for nonlinear Landau damping of
EAWs. An approximate soliton solution of the KdV equation is also obtained, and
it is shown that the nonlinear Landau damping causes the wave amplitude to
decay slowly with time compared to the classical theory.",2106.12754v2
2021-09-27,Mitigation of Rayleigh-like waves in granular media via multi-layer resonant metabarriers,"In this work, we experimentally and numerically investigate the propagation
and attenuation of vertically polarized surface waves in an unconsolidated
granular medium equipped with small-scale metabarriers of different depths,
i.e., arrays composed of one, two, and three embedded layers of sub-wavelength
resonators. Our findings reveal how such a multi-layer arrangement strongly
affects the attenuation of the surface wave motion within and after the
barrier. When the surface waves collide with the barriers, the wavefront is
back-scattered and steered downward underneath the oscillators. Due to the
stiffness gradient of the granular medium, part of the wavefield is then
rerouted to the surface level after overcoming the resonant array. Overall, the
in-depth insertion of additional layers of resonators leads to a greater and
broader band wave attenuation when compared to the single layer case.",2109.12917v1
2022-12-09,Resonance states at Casati wave numbers for the 3-disk billiard,"Resonance states of the 3-disk scattering system are presented for the first
Casati wave number $k \approx 912$ and the second Casati wave number $k \approx
91242$. They show multifractal structure in phase space, similar to the
pioneering work by Casati et al. [Physica D 131, 311 (1999)] for an open
chaotic quantum map. In position space we observe scarring along segments of
rays, related to multifractality and universal fluctuations, as recently found
for dielectric cavities. To the best of our knowledge this resonance state at
the second Casati wave number has a much larger wave number than published
resonance states for the 3-disk scattering system or any other open or closed
chaotic billiard.",2212.04787v1
2023-01-23,"Comment on: ""Interacting quantum and classical waves: Resonant and non-resonant energy transfer to electrons immersed in an intense electromagnetic wave'' [Phys. Plasmas 29, 022107 (2022)]","A comment on the paper by S. M. Mahajan and F. A. Asenjo ""Interacting quantum
and classical waves: Resonant and non-resonant energy transfer to electrons
immersed in an intense electromagnetic wave"" [Phys. Plasmas 29, 022107 (2022)]
where the authors use a model based on the Klein-Gordon equation to discuss
particle energization by a transverse electromagnetic wave in a plasma. It is
shown that the results of the paper are easily obtained in a classical
approach, so that no quantum effect has to be invoked. Moreover, some mistakes
and misinterpretations in the paper have been corrected. The (un)suitability of
the proposed mechanism to account for generation of extremely energetic
particles in both laboratory and astrophysical scenarios is also discussed.",2301.09718v2
2023-11-30,Parametric resonance of gravitational waves in general scalar-tensor theories,"Gravitational waves offer a potent mean to test the underlying theory of
gravity. In general theories of gravity, such as scalar-tensor theories, one
expects modifications in the friction term and the sound speed in the
gravitational wave equation. In that case, rapid oscillations in such
coefficients, e.g. due to an oscillating scalar field, may lead to narrow
parametric resonances in the gravitational wave strain. We perform a general
analysis of such possibility within DHOST theories. We use disformal
transformations to find the theory space with larger resonances, within an
effective field theory approach. We then apply our formalism to a non-minimally
coupled ultra-light dark matter scalar field, assuming the presence of a
primordial gravitational wave background, e.g., from inflation. We find that
the resonant peaks in the spectral density may be detectable by forthcoming
detectors such as LISA, Taiji, Einstein Telescope and Cosmic Explorer.",2311.18546v1
2021-04-19,Orbital ordering and fluctuations in a kagome superconductor CsV3Sb5,"Recently, competing electronic instabilities, including superconductivity and
density-wave-like order, have been discovered in vanadium-based kagome metals
AV3Sb5 (A = K, Rb, Cs) with a nontrivial band topology. This finding stimulates
wide interests to study the interplay of these competing electronic orders and
possible exotic excitations in the superconducting state. Here, in order to
further clarify the nature of density-wave-like transition in these kagome
superconductors, we performed 51V and 133Cs nuclear magnetic resonance (NMR)
measurements on the CsV3Sb5 single crystal. A first-order phase transition
associated with orbital ordering is revealed by observing a sudden splitting of
orbital shift in 51V NMR spectrum at the structural transition temperature Ts ~
94 K. In contrast, the quadrupole splitting from a charge-density-wave (CDW)
order on 51V NMR spectrum only appears gradually below Ts with a typical
second-order transition behavior, suggesting that the CDW order is a secondary
electronic order. Moreover, combined with 133Cs NMR spectrum, the present
result also confirms a three-dimensional structural modulation with a 2ax2ax2c
period. Above Ts, the temperature-dependent Knight shift and nuclear
spin-lattice relaxation rate (1/T1) further indicate the existence of
remarkable magnetic fluctuations from vanadium 3d orbitals, which are
suppressed due to orbital ordering below Ts. The present results strongly
support that, besides CDW order, the previously claimed density-wave-like
transition also involves a dominant orbital order, suggesting a rich orbital
physics in these kagome superconductors.",2104.09173v1
2020-07-24,Multiband gravitational-wave searches for ultralight bosons,"Gravitational waves may be one of the few direct observables produced by
ultralight bosons, conjectured dark matter candidates that could be the key to
several problems in particle theory, high-energy physics and cosmology. These
axionlike particles could spontaneously form ""clouds"" around astrophysical
black holes, leading to potent emission of continuous gravitational waves that
could be detected by instruments on the ground and in space. Although this
scenario has been thoroughly studied, it has not been yet appreciated that both
types of detector may be used in tandem (a practice known as ""multibanding"").
In this paper, we show that future gravitational-wave detectors on the ground
and in space will be able to work together to detect ultralight bosons with
masses $25 \lesssim \mu/\left(10^{-15}\, \mathrm{eV}\right)\lesssim 500$. In
detecting binary-black-hole inspirals, the LISA space mission will provide
crucial information enabling future ground-based detectors, like Cosmic
Explorer or Einstein Telescope, to search for signals from boson clouds around
the individual black holes in the observed binaries. We lay out the detection
strategy and, focusing on scalar bosons, chart the suitable parameter space. We
study the impact of ignorance about the system's history, including cloud age
and black hole spin. We also consider the tidal resonances that may destroy the
boson cloud before its gravitational signal becomes detectable by a
ground-based follow-up. Finally, we show how to take all of these factors into
account, together with uncertainties in the LISA measurement, to obtain boson
mass constraints from the ground-based observation facilitated by LISA.",2007.12793v2
2007-10-28,Some symmetry properties of spin currents and spin polarizations in multi-terminal mesoscopic spin-orbit coupled systems,"We study theoretically some symmetry properties of spin currents and spin
polarizations in multi-terminal mesoscopic spin-orbit coupled systems. Based on
a scattering wave function approach, we show rigorously that in the equilibrium
state no finite spin polarizations can exist in a multi-terminal mesoscopic
spin-orbit coupled system (both in the leads and in the spin-orbit coupled
region) and also no finite equilibrium terminal spin currents can exist. By use
of a typical two-terminal mesoscopic spin-orbit coupled system as the example,
we show explicitly that the nonequilibrium terminal spin currents in a
multi-terminal mesoscopic spin-orbit coupled system are non-conservative in
general. This non-conservation of terminal spin currents is not caused by the
use of an improper definition of spin current but is intrinsic to
spin-dependent transports in mesoscopic spin-orbit coupled systems. We also
show that the nonequilibrium lateral edge spin accumulation induced by a
longitudinal charge current in a thin strip of \textit{finite} length of a
two-dimensional electronic system with intrinsic spin-orbit coupling may be
non-antisymmetric in general, which implies that some cautions may need to be
taken when attributing the occurrence of nonequilibrium lateral edge spin
accumulation induced by a longitudinal charge current in such a system to an
intrinsic spin Hall effect.",0710.5316v1
2007-02-27,Nuclear Magnetic Resonance Imaging with 90 nm Resolution,"Magnetic resonance imaging, based on the manipulation and detection of
nuclear spins, is a powerful imaging technique that typically operates on the
scale of millimeters to microns. Using magnetic resonance force microscopy, we
have demonstrated that magnetic resonance imaging of nuclear spins can be
extended to a spatial resolution better than 100 nm. The two-dimensional
imaging of 19F nuclei was done on a patterned CaF2 test object, and was enabled
by a detection sensitivity of roughly 1200 nuclear spins. To achieve this
sensitivity, we developed high-moment magnetic tips that produced field
gradients up to 1.4x10^6 T/m, and implemented a measurement protocol based on
force-gradient detection of naturally occurring spin fluctuations. The
resulting detection volume of less than 650 zl represents 60,000x smaller
volume than previous NMR microscopy and demonstrates the feasibility of pushing
magnetic resonance imaging into the nanoscale regime.",0702664v1
2008-12-31,A new mechanism of electric dipole spin resonance: hyperfine coupling in quantum dots,"A recently discovered mechanism of electric dipole spin resonance, mediated
by the hyperfine interaction, is investigated experimentally and theoretically.
The effect is studied using a spin-selective transition in a GaAs double
quantum dot. The resonant frequency is sensitive to the instantaneous hyperfine
effective field, revealing a nuclear polarization created by driving the
resonance. A device incorporating a micromagnet exhibits a magnetic field
difference between dots, allowing electrons in either dot to be addressed
selectively. An unexplained additional signal at half the resonant frequency is
presented.",0901.0124v1
2009-10-15,Disorder effect of resonant spin Hall effect in a tilted magnetic field,"We study the disorder effect of resonant spin Hall effect in a two-dimension
electron system with Rashba coupling in the presence of a tilted magnetic
field. The competition between the Rashba coupling and the Zeeman coupling
leads to the energy crossing of the Landau levels, which gives rise to the
resonant spin Hall effect. Utilizing the Streda's formula within the
self-consistent Born approximation, we find that the impurity scattering
broadens the energy levels, and the resonant spin Hall conductance exhibits a
double peak around the resonant point, which is recovered in an applied titled
magnetic field.",0910.2869v1
2010-01-19,Spin determination of single-produced resonances at hadron colliders,"We study the production of a single resonance at the LHC and its decay into a
pair of Z bosons. We demonstrate how full reconstruction of the final states
allows us to determine the spin and parity of the resonance and restricts its
coupling to vector gauge bosons. Full angular analysis is illustrated with the
simulation of the production and decay chain including all spin correlations
and the most general couplings of spin-zero, -one, and -two resonances to
Standard Model matter and gauge fields. We note implications for analysis of a
resonance decaying to other final states.",1001.3396v2
2011-04-14,Odd Parity Light Baryon Resonances,"We use a consistent SU(6) extension of the meson-baryon chiral Lagrangian
within a coupled channel unitary approach in order to calculate the T-matrix
for meson-baryon scattering in s-wave. The building blocks of the scheme are
the pion and nucleon octets, the rho nonet and the Delta decuplet. We identify
poles in this unitary T-matrix and interpret them as resonances. We study here
the non exotic sectors with strangeness S=0,-1,-2,-3 and spin J=1/2, 3/2 and
5/2. Many of the poles generated can be associated with known N, Delta, Sigma,
Lambda and Xi resonances with negative parity. We show that most of the
low-lying three and four star odd parity baryon resonances with spin 1/2 and
3/2 can be related to multiplets of the spin-flavor symmetry group SU(6). This
study allows us to predict the spin-parity of the Xi(1620), Xi(1690), Xi(1950),
Xi(2250), Omega(2250) and Omega(2380) resonances, which have not been
determined experimentally yet.",1104.2737v2
2011-05-23,Heavy quark spin structure in Z_b resonances,"We discuss the heavy quark spin structure of the recently observed `twin'
resonances $Z_b(10610)$ and $Z_b(10650)$ assuming that these are mostly of a
`molecular' type, i.e. that their internal dynamics is dominated by the
coupling to meson pairs $B^* \bar B - B {\bar B}^*$ and $B^* {\bar B}^*$. We
find that the state of the $b \bar b$ pair within the $Z_b(10610)$ and
$Z_b(10650)$ resonances is a mixture of a spin-triplet and a spin-singlet of
equal amplitude and with the phase orthogonal between the two resonances. Such
a structure gives rise to specific relations between observable amplitudes that
are in agreement with the data obtained recently by Belle. We also briefly
discuss possible properties of the isotopically singlet counterparts of the
newly found resonances, and also of their $C$ ($G$) parity opposites that
likely exist in the same mass range near the open $B$ flavor threshold.",1105.4473v2
2015-04-15,Resonant scattering by magnetic impurities as a model for spin relaxation in bilayer graphene,"We propose that the observed spin-relaxation in bilayer graphene is due to
resonant scattering by magnetic impurities. We analyze a resonant scattering
model due to adatoms on both dimer and non-dimer sites, finding that only the
former give narrow resonances at the charge neutrality point. Opposite to
single-layer graphene, the measured spin-relaxation rate in graphene bilayer
increases with carrier density. Although it has been commonly argued that a
different mechanism must be at play for the two structures, our model explains
this behavior rather naturally in terms of different broadening scales for the
same underlying resonant processes. Not only our results---using robust and
first-principles inspired parameters---agree with experiment, they also predict
an experimentally testable sharp decrease of the spin-relaxation rate at high
carrier densities.",1504.03898v2
2020-04-07,Horizontal Line Nodes in Sr2RuO4 Proved by Spin Resonance,"We investigated the low-energy incommensurate (IC) magnetic fluctuations in
Sr$_2$RuO$_4$ by the high-resolution inelastic neutron scattering measurements
and random phase approximation (RPA) calculations. We observed a spin resonance
with energy of $\hbar\omega_\text{res}=0.56$~meV centered at a characteristic
wavevector $\mathbf{Q}_\text{res}=(0.3, 0.3, 0.5)$. The resonance energy
corresponds well to the superconducting gap $2\Delta=0.56$~meV estimated by the
tunneling spectroscopy. The spin resonance shows the $L$ modulation with a
maximum at around $L = 0.5$. The $L$ modulated intensity of the spin resonance
and our RPA calculations indicate that the superconducting gaps regarding the
quasi-one-dimensional $\alpha$ and $\beta$ sheets at the Fermi surfaces have
the horizontal line nodes. These results may set a strong constraint on the
pairing symmetry of Sr$_2$RuO$_4$. We also discuss the implications on possible
superconducting order parameters.",2004.03591v1
2019-03-10,Coherent long-distance spin-qubit-transmon coupling,"Spin qubits and superconducting qubits are among the promising candidates for
a solid state quantum computer. For the implementation of a hybrid architecture
which can profit from the advantages of either world, a coherent long-distance
link is necessary that integrates and couples both qubit types on the same
chip. We realize such a link with a frequency-tunable high impedance SQUID
array resonator. The spin qubit is a resonant exchange qubit hosted in a GaAs
triple quantum dot. It can be operated at zero magnetic field, allowing it to
coexist with superconducting qubits on the same chip. We find a working point
for the spin qubit, where the ratio between its coupling strength and
decoherence rate is optimized. We observe coherent interaction between the
resonant exchange qubit and a transmon qubit in both resonant and dispersive
regimes, where the interaction is mediated either by real or virtual resonator
photons.",1903.04022v1
2019-04-17,A cotunneling mechanism for all-electrical Electron Spin Resonance of single adsorbed atoms,"The recent development of all-electrical electron spin resonance (ESR) in a
scanning tunneling microscope (STM) setup has opened the door to vast
applications. Despite the fast growing number of experimental works on STM-ESR,
the fundamental principles remains unclear. By using a cotunneling picture, we
show that the spin resonance signal can be explained as a time-dependent
variation of the tunnel barrier induced by the alternating electric driving
field. We demonstrate how this variation translates into the resonant frequency
response of the direct current. Our cotunneling theory explains the main
experimental findings. Namely, the linear dependence of the Rabi flop rate with
the alternating bias amplitude, the absence of resonant response for
spin-unpolarized currents, and the weak dependence on the actual atomic
species.",1904.08183v1
2020-06-14,Resonant-amplified and invisible Bragg scattering based on spin coalescing modes,"Unlike a real magnetic field, which separates the energy levels of particle
with opposite spin polarization, a complex field can lead to a special kind of
spectral degeneracy, known as exceptional point (EP), at which two spin
eigenmodes coalesce. It allows an EP impurity to be an invisible scattering
center for a fermion with the resonant spin polarization, but an amplifying
emitter for opposite polarization. We show that a pair of conjugate EP modes
supports resonant mutual stimulation, acting as a resonant amplifier based on
the underlying mechanism of positive-feedback loop. Together with other
Hermitian eigenmodes, a fermion with EP polarization exhibits some exclusive
dynamics, referred to as EP dynamics. We construct several typical
superlattices, which are built up by embedding EP-impurity arrays in a
Hermitian two-dimensional square lattice. Numerical simulations are performed
to demonstrate resonant amplification and invisibility of Bragg scattering.",2006.07875v2
2023-11-07,Latched Detection of Zeptojoule Spin Echoes with a Kinetic Inductance Parametric Oscillator,"When strongly pumped at twice their resonant frequency, non-linear resonators
develop a high-amplitude intracavity field, a phenomenon known as parametric
self-oscillations. The boundary over which this instability occurs can be
extremely sharp and thereby presents an opportunity for realizing a detector.
Here we operate such a device based on a superconducting microwave resonator
whose non-linearity is engineered from kinetic inductance. The device indicates
the absorption of low-power microwave wavepackets by transitioning to a
self-oscillating state. Using calibrated wavepackets we measure the detection
efficiency with zeptojoule energy wavepackets. We then apply it to measurements
of electron spin resonance, using an ensemble of $^{209}$Bi donors in silicon
that are inductively coupled to the resonator. We achieve a latched-readout of
the spin signal with an amplitude that is five hundred times greater than the
underlying spin echoes.",2311.03702v1
2011-02-14,Resonant enhancement of ultracold photoassociation rate by electric field induced anisotropic interaction,"We study the effects of a static electric field on the photoassociation of a
heteronuclear atom-pair into a polar molecule. The interaction of permanent
dipole moment with a static electric field largely affects the ground state
continuum wave function of the atom-pair at short separations where
photoassociation transitions occur according to Franck-Condon principle.
Electric field induced anisotropic interaction between two heteronuclear ground
state atoms leads to scattering resonances at some specific electric fields.
Near such resonances the amplitude of scattering wave function at short
separation increases by several orders of magnitude. As a result,
photoaasociation rate is enhanced by several orders of magnitude near the
resonances. We discuss in detail electric field modified atom-atom scattering
properties and resonances. We calculate photoassociation rate that shows giant
enhancement due to electric field tunable anisotropic resonances. We present
selected results among which particularly important are the excitations of
higher rotational levels in ultracold photoassociation due to electric field
tunable resonances.",1102.2687v2
2014-05-11,A mathematical theory of super-resolution by using a system of sub-wavelength Helmholtz resonators,"A rigorous mathematical theory is developed to explain the super-resolution
phenomenon observed in the experiment by F.Lemoult, M.Fink and G.Lerosey
(Acoustic resonators for far-field control of sound on a subwavelength scale,
Phys. Rev. Lett., 107 (2011)). A key ingredient is the calculation of the
resonances and the Green function in the half space with the presence of a
system of Helmholtz resonators in the quasi-stationary regime. By using
boundary integral equations and generalized Rouche's theorem, the existence and
the leading asymptotic of the resonances are rigorously derived. The integral
equation formulation also yields the leading order terms in the asymptotics of
the Green function. The methodology developed in the paper provides an elegant
and systematic way for calculating resonant frequencies for Helmholtz
resonators in assorted space settings as well as in various frequency regimes.
By using the asymptotics of the Green function, the analysis of the imaging
functional of the time-reversal wave fields becomes possible, which clearly
demonstrates the super-resolution property. The result provides the first
mathematical theory of super-resolution in the context of a deterministic
medium and sheds light to the mechanism of super-resolution and super-focusing
for waves in deterministic complex media.",1405.2513v1
2015-09-18,Resonant and Non-Local Properties of Phononic Metasolids,"We derive a general theory of effective properties in metasolids based on
phononic crystals with low frequency resonances. We demonstrate that in general
these structures need to be described by means of a frequency-dependent and
non-local anisotropic mass density, stiffness tensor and a third- rank coupling
tensor, which shows that they behave like a non-local Willis medium. The effect
of non-locality and coupling tensor manifest themselves for some particular
resonances whereas they become negligible for other resonances. Considering the
example of a two-dimensional phononic crystal, consisting of triangular
arrangements of cylindrical shells in an elastic matrix, we show that its mass
density tensor is strongly resonant and anisotropic presenting both positive
and negative divergent values, while becoming scalar in the quasi-static limit.
Moreover, it is found that the negative value of transverse component of the
mass density is induced by a dipolar resonance, while that of the vertical
component is induced by a monopolar one. Finally, the dispersion relation
obtained by the effective parameters of the crystal is compared with the band
structure, showing a good agreement for the low-wave number region, although
the non-local effects are important given the existence of some resonant values
of the wave number.",1509.05522v1
2018-01-09,Three-neutron resonance study using transition operators,"Existing bound-state type calculations of three-neutron resonances yield
contradicting results. A direct study of the three-neutron continuum using
rigorous scattering equations with realistic potentials and search for possible
resonances is aimed. Faddeev-type integral equations for three-neutron
transition operators are solved in the momentum-space partial-wave framework.
The evolution of resonances is studied by enhancing the strength of the
two-neutron interaction in partial waves with nonzero orbital momentum.
Calculated three-neutron transition operators exhibit resonant behavior for
sufficiently large enhancement factors; pole trajectories in the complex-energy
energy plane are extracted from their energy dependence. However, the resonant
behavior completely disappears for the physical interaction strength. There are
no physically observable three-neutron resonant states consistent with
presently accepted interaction models.",1801.02919v2
2018-08-30,Tuning of envelope in high overtone bulk acoustic wave resonator,"This report presents a robust composite resonator known as the high overtone
bulk acoustic wave resonator (HBAR) for demonstrating experimentally the
ability of the resonator to tune the envelope of the spectrum by applying dc
bias. The reported HBAR exhibits exceptionally high-quality factor in the
frequency range of 700 MHz to 3 GHz and high effective coupling coefficient
over the broad range of microwave frequencies. The HBAR is based on thin
Ba0.5Sr0.5TiO3 film sandwiched between two electrodes forming a transducer,
supported by a thick sapphire substrate which is a low acoustic loss material.
The resonator works on the principle of induced piezoelectricity due to the
applied dc bias. The minima of the envelope changes from 1.16 GHz with S11 of
-3.51 dB at 100 kV/cm bias to 1.90 GHz with S11 of -42.23 dB at 700 kV/cm bias,
giving a relative tunability of the envelope to be around 64%. The spacing of
the parallel resonance frequency (SPRF) for different bias voltages are also
presented in this report. The quality factor of the resonator is over 22,000 at
around 2GHz.",1808.10115v1
2020-07-29,Resonant bending of silicon nanowires by light,"Coupling of two dielectric wires with rectangular cross-section gives rise to
bonding and anti-bonding resonances. The latter is featured by extremal
narrowing of the resonant width for variation of the aspect ratio of the
cross-section and distance between wires when the morphology of the
anti-bonding resonant mode approaches to the morphology of the Mie resonant
mode of effective circular wire with high azimuthal index. Then plane wave
resonant to this anti-bonding resonance gives rise to unprecedent enhancement
of the optical forces up to several nano Newtons per micron length of wires.
The forces oscillate with angle of incidence of plane wave but always try to
repel the wires. If the wires are fixed at the ends the optical forces result
in elastic deflection of wires of order $100 nm$ for wires's length $50\mu m$
and the light power $1.5mW/\mu m^2$.",2007.15434v1
2021-05-10,"Resonant interaction in chiral, Eshelby-twisted van der Waals atomic layers","We study the electronic structures of chiral, Eshelby-twisted van der Waals
atomic layers with a particular focus on a chiral twisted graphite (CTG), a
graphene stack with a constant twist angle $\theta$ between successive layers.
We show that each CTG can host infinitely many resonant states which arise from
the interaction between the degenerate monolayer states of the constituent
layers. Each resonant state has a screw rotational symmetry, and may have a
smaller reduced Brillouin zone than other non-resonant states in the same
structure. And each CTG can have the resonant states with up to four different
screw symmetries. We derive the energies and wave functions of the resonant
states in a universal form of a one-dimensional chain regardless of $\theta$,
and show that these states exhibit a clear optical selection rule for
circularly polarized light. Finally, we discuss the uniqueness and existence of
the exact center of the lattice and the self-similarity of the wave amplitudes
of the resonant states.",2105.04139v2
2022-02-07,Broadband Resonance-Enhanced Frequency Generation by Four-Wave Mixing in a Silicon Floquet Topological Photonic Insulator,"Floquet topological photonic insulators, whose light transport properties are
dictated by the periodic drive sequence of the lattice, provide more
flexibility for controlling and trapping light than undriven topological
insulators, which can enable novel nonlinear optics applications in topological
photonics. Here, we employ a novel resonance effect called Floquet Defect Mode
Resonance in a 2D silicon Floquet microring lattice to demonstrate
resonance-enhanced frequency generation by four-wave mixing of Floquet bulk
modes in the presence of Kerr nonlinearity. The compact, cavity-less resonance
mode, induced through a periodic perturbation of the lattice drive sequence,
has the largest reported Q-factor for a topological resonator of ~10^5 with low
group velocity dispersion, which enables efficient broadband frequency
generation over several Floquet-Brillouin zones of the Floquet topological
insulator. We achieved wavelength conversion over 10.1 nm spectral range with
an average enhancement of 12.5 dB in the conversion efficiency due to the
Floquet Defect Mode Resonance. Our work could lead to robust light sources
generated directly on a topologically-protected photonic platform.",2202.03552v1
2022-10-17,Transduction of single nanomechanical pillar resonators by scattering of surface acoustic waves,"One of the challenges of nanoelectromechanical systems (NEMS) is the
effective transduction of the tiny resonators. Vertical structures, such as
nanomechanical pillar resonators, which are exploited in a wide range of
fields, such as optomechanics, acoustic metamaterials, and nanomechanical
sensing, are particularly challenging to transduce. Existing electromechanical
transduction methods are ill-suited as they complicate the pillars' fabrication
process, put constraints on the pillars' material, and do not enable a
transduction of freestanding pillars. Here, we present an electromechanical
transduction method for single nanomechanical pillar resonators based on
surface acoustic waves (SAWs). We demonstrate the transduction of freestanding
nanomechanical platinum-carbon pillars in the first-order bending and
compression mode. Since the principle of the transduction method is based on
resonant scattering of a SAW by a nanomechanical resonator, our transduction
method is independent of the pillar's material and not limited to pillar-shaped
geometries. It represents a general method to transduce vertical mechanical
resonators with nanoscale lateral dimensions.",2210.09069v2
2023-11-09,Magnon-phonon coupling of synthetic antiferromagnets in a surface acoustic wave cavity resonator,"We use a surface acoustic wave (SAW) cavity resonator to study the coupling
of acoustic magnons in a synthetic antiferromagnet (SAF) and the phonons
carried by SAWs. The SAF is composed of a CoFeB/Ru/CoFeB trilayer and the
scattering matrix of the SAW resonator is studied to assess the coupling. We
find that the spectral linewidth of the SAW resonator is modulated when the
frequency of the excited magnons approaches the SAW resonance frequency.
Moreover, the linewidth modulation varies with the magnitude and orientation of
the external magnetic field. Such change in the spectral linewidth can be well
reproduced using macrospin-like model calculations. From the model analyses, we
estimate the magnon-phonon coupling strength to be $\sim$15.6 MHz at a SAW
resonance frequency of 1.8 GHz: the corresponding magnomechanical cooperativity
is $\sim$0.66. As the spectral shape hardly changes in a CoFeB single layer
reference sample under the same experimental condition, these results show that
SAF provides an ideal platform to study magnon-phonon coupling in a SAW cavity
resonator.",2311.05275v1
2004-08-10,Coherent optical control of spin-spin interaction in doped semiconductors,"We provide a theory of laser-induced interaction between spins localized by
impurity centers in a semiconductor host. By solving exactly the problem of two
localized spins interacting with one itinerant exciton, an analytical
expression for the induced spin-spin interaction is given as a function of the
spin separation, laser energy, and intensity. We apply the theory to shallow
neutral donors (Si) and deep rare-earth magnetic impurities (Yb) in III-V
semiconductors. When the photon energy approaches a resonance related to
excitons bound to the impurities, the coupling between the localized spins
increases, and may change from ferromagnetic to anti-ferromagnetic. This
light-controlled spin interaction provides a mechanism for the quantum control
of spins in semiconductors for quantum information processing; it suggests the
realization of spin systems whose magnetic properties can be controlled by
changing the strength and the sign of the spin-spin interaction.",0408216v1
2007-07-31,Theory of spin qubits in nanostructures,"We review recent advances on the theory of spin qubits in nanostructures. We
focus on four selected topics. First, we show how to form spin qubits in the
new and promising material graphene. Afterwards, we discuss spin relaxation and
decoherence in quantum dots. In particular, we demonstrate how charge
fluctations in the surrounding environment cause spin decay via spin--orbit
coupling. We then turn to a brief overview of how one can use electron-dipole
spin resonance (EDSR) to perform single spin rotations in quantum dots using an
oscillating electric field. The final topic we cover is the spin-spin coupling
via spin-orbit interaction which is an alternative to the usual spin-spin
coupling via the Heisenberg exchange interaction.",0707.4622v1
2009-09-21,Engineering ultralong spin coherence in two-dimensional hole systems at low temperatures,"For the realisation of scalable solid-state quantum-bit systems, spins in
semiconductor quantum dots are promising candidates. A key requirement for
quantum logic operations is a sufficiently long coherence time of the spin
system. Recently, hole spins in III-V-based quantum dots were discussed as
alternatives to electron spins, since the hole spin, in contrast to the
electron spin, is not affected by contact hyperfine interaction with the
nuclear spins. Here, we report a breakthrough in the spin coherence times of
hole ensembles, confined in so called natural quantum dots, in narrow
GaAs/AlGaAs quantum wells at temperatures below 500 mK. Consistently,
time-resolved Faraday rotation and resonant spin amplification techniques
deliver hole-spin coherence times, which approach in the low magnetic field
limit values above 70 ns. The optical initialisation of the hole spin
polarisation, as well as the interconnected electron and hole spin dynamics in
our samples are well reproduced using a rate equation model.",0909.3711v3
2011-07-21,Theory of a.c. spin current noise and spin conductance through a quantum dot in the Kondo regime I: The equilibrium case,"We analyze the equilibrium frequency-dependent spin current noise and spin
conductance through a quantum dot in the local moment regime. Spin current
correlations behave markedly differently from charge correlations. Equilibrium
spin correlations are characterized by two universal scaling functions in the
absence of an external field: one of them is related to charge correlations,
while the other one describes cross-spin correlations. We characterize these
functions using a combination of perturbative and non-perturbative methods. We
find that at low temperatures spin cross-correlations are suppressed at
frequencies below the Kondo scale, $T_K$, and a dynamical spin accumulation
resonance is found at the Kondo energy, $\omega \sim T_K$. At higher
temperatures, $T>T_K$, surprising low-frequency anomalies related to overall
spin conservation appear in the spin noise and spin conductance, and the
Korringa rate is shown to play a distinguished role. The transient spin current
response also displays universal and singular properties.",1107.4265v1
2015-03-13,Comparison of spin-orbit torques and spin pumping across NiFe/Pt and NiFe/Cu/Pt interfaces,"We experimentally investigate spin-orbit torques and spin pumping in NiFe/Pt
bilayers with direct and interrupted interfaces. The damping-like and
field-like torques are simultaneously measured with spin-torque ferromagnetic
resonance tuned by a dc bias current, whereas spin pumping is measured
electrically through the inverse spin Hall effect using a microwave cavity.
Insertion of an atomically thin Cu dusting layer at the interface reduces the
damping-like torque, field-like torque, and spin pumping by nearly the same
factor of ~1.4. This finding confirms that the observed spin-orbit torques
predominantly arise from diffusive transport of spin current generated by the
spin Hall effect. We also find that spin-current scattering at the NiFe/Pt
interface contributes to additional enhancement in magnetization damping that
is distinct from spin pumping.",1503.04104v3
2016-09-12,Spin decoherence of magnetic atoms on surfaces,"We review the problem of spin decoherence of magnetic atoms deposited on a
surface. Recent breakthroughs in scanning tunnelling microscopy (STM) make it
possible to probe the spin dynamics of individual atoms, either isolated or
integrated in nanoengineered spin structures. Transport pump and probe
techniques with spin polarized tips permit measuring the spin relaxation time
$T_1$, while novel demonstration of electrically driven STM single spin
resonance has provided a direct measurement of the spin decoherence time $T_2$
of an individual magnetic adatom. Here we address the problem of spin
decoherence from the theoretical point of view. First we provide a short
general overview of decoherence in open quantum systems and we discuss with
some detail ambiguities that arise in the case of degenerate spectra, relevant
for magnetic atoms. Second, we address the physical mechanisms that allows
probing the spin coherence of magnetic atoms on surfaces. Third, we discuss the
main spin decoherence mechanisms at work on a surface, most notably, Kondo
interaction, but also spin-phonon coupling and dephasing by Johnson noise.
Finally, we propose some schemes to engineer spin decoherence.",1609.03389v2
2018-07-11,Enhanced quantum coherence in exchange coupled spins via singlet-triplet transitions,"Manipulation of spin states at the single-atom scale underlies spin-based
quantum information processing and spintronic devices. Such applications
require protection of the spin states against quantum decoherence due to
interactions with the environment. While a single spin is easily disrupted, a
coupled-spin system can resist decoherence by employing a subspace of states
that is immune to magnetic field fluctuations. Here, we engineered the magnetic
interactions between the electron spins of two spin-1/2 atoms to create a clock
transition and thus enhance their spin coherence. To construct and electrically
access the desired spin structures, we use atom manipulation combined with
electron spin resonance (ESR) in a scanning tunneling microscope (STM). We show
that a two-level system composed of a singlet state and a triplet state is
insensitive to local and global magnetic field noise, resulting in much longer
spin coherence times compared with individual atoms. Moreover, the spin
decoherence resulting from the interaction with tunneling electrons is markedly
reduced by a homodyne readout of ESR. These results demonstrate that
atomically-precise spin structures can be designed and assembled to yield
enhanced quantum coherence.",1807.04322v1
2019-05-02,Long-Range Microwave Mediated Interactions Between Electron Spins,"Entangling gates for electron spins in semiconductor quantum dots are
generally based on exchange, a short-ranged interaction that requires
wavefunction overlap. Coherent spin-photon coupling raises the prospect of
using photons as long-distance interconnects for spin qubits. Realizing a key
milestone for spin-based quantum information processing, we demonstrate
microwave-mediated spin-spin interactions between two electrons that are
physically separated by more than 4 mm. Coherent spin-photon coupling is
demonstrated for each individual spin using microwave transmission
spectroscopy. An enhanced vacuum Rabi splitting is observed when both spins are
tuned into resonance with the cavity, indicative of a coherent spin-spin
interaction. Our results demonstrate that microwave-frequency photons can be
used as a resource to generate long-range two-qubit gates between spatially
separated spins.",1905.00776v1
2016-11-23,Room temperature manipulation of long lifetime spins in metallic-like carbon nanospheres,"The time-window for processing electron spin information (spintronics) in
solid-state quantum electronic devices is determined by the spin-lattice (T1)
and spin-spin (T2) relaxation times of electrons. Minimising the effects of
spin-orbit coupling and the local magnetic contributions of neighbouring atoms
on T1 and T2 at room temperature remain substantial challenges to practical
spintronics. Here, we report a record-high conduction electron T1=T2 of 175 ns
at 300 K in 37 nm +/- 7 nm carbon spheres, which exceeds by far the highest
values observed for any conducting solid state material of comparable size. The
long T1=T2 is due to quantum confinement effects, to the intrinsically weak
spin-orbit coupling of carbon, and to the protecting nature of the outer shells
of the inner spins from the influences of environmental disturbances. Following
the observation of spin polarization by electron spin resonance, we controlled
the quantum state of the electron spin by applying short bursts of an
oscillating magnetic field and observed coherent oscillations of the spin
state. These results demonstrate the feasibility of operating electron spins in
conducting carbon nanospheres as quantum bits at room temperature.",1611.07690v1
2020-06-02,Spin pumping and inverse spin Hall effect in iridium oxide,"Large charge-to-spin conversion (spin Hall angle) and spin Hall conductivity
are prerequisites for development of next generation power efficient spintronic
devices. In this context, heavy metals (e.g. Pt, W etc.), topological
insulators, antiferromagnets are usually considered because they exhibit high
spin-orbit coupling (SOC). In addition to the above materials, 5d transition
metal oxide e.g. Iridium Oxide (IrO 2 ) is a potential candidate which exhibits
high SOC strength. Here we report a study of spin pumping and inverse spin Hall
effect (ISHE), via ferromagnetic resonance (FMR), in IrO 2 /CoFeB system. We
identify the individual contribution of spin pumping and other spin
rectification effects in the magnetic layer, by investigating the in-plane
angular dependence of ISHE signal. Our analysis shows significant contribution
of spin pumping effect to the ISHE signal. We show that polycrystalline IrO 2
thin film exhibits high spin Hall conductivity and spin Hall angle which are
comparable to the values of Pt.",2006.01865v2
2024-02-16,Fractional Spin Quantum Hall Effect in Weakly Coupled Spin Chain Arrays,"Topological magnetic insulators host chiral gapless edge modes. In the
presence of strong interaction effects, the spin of these modes may
fractionalize. Studying a 2D array of coupled insulating spin-1/2 chains, we
show how spatially modulated magnetic fields and Dzyaloshinskii-Moriya
interactions can be exploited to realize chiral spin liquids or integer and
fractional spin quantum Hall effect phases. These are characterized by a gapped
bulk spectrum and gapless chiral edge modes with fractional spin. The spin
fractionalization is manifested in the quantized spin conductance, which can be
used to probe the fractional spin quantum Hall effect. We analyze the system
via bosonization and perturbative renormalization group techniques that allow
us to identify the most relevant terms induced by the spin-spin interactions
that open gaps and render the system topological under well-specified resonance
conditions. We show explicitly that the emerging phase is a genuine chiral spin
liquid. We suggest that the phases can be realized experimentally in synthetic
spin chains and ultracold atom systems.",2402.10849v1
2000-12-18,New Origin For Spin Current And Current-Induced Spin Precession In Magnetic Multilayers,"In metallic ferromagnets, an electric current is accompanied by a flux of
angula r momentum, also called spin current. In multilayers, spatial variations
of the spin current correspond to drive torques exerted on a magnetic layer.
These torq ues result in spin precession above a certain current threshold. The
usual kind of spin current is associated with translation of the spin-up and
spin-down Ferm i surfaces in momentum space. We discuss a different kind of
spin current, assoc iated with expansion and contraction of the Fermi surfaces.
It is more nonlocal in nature, and may exist even in locations where the
electrical current density is zero. It is larger than the usual spin current,
in a ratio of 10 or 100, and is dominant in most cases. The new spin current is
proportional to the differenc e Delta-mu = 0.001 eV between spin-up and
spin-down Fermi levels, averaged over the entire Fermi surface. Conduction
processes, spin relaxation, and spin-wave emission in the multilayer can be
described by an equivalent electrical circuit resembling an unbalanced dc
Wheatstone bridge. And Delta-mu corresponds to the output voltage of the
bridge.",0012337v2
2003-10-15,Central limit theorems for the large-spin asymptotics of quantum spins,"We use a generalized form of Dyson's spin wave formalism to prove several
central limit theorems for the large-spin asymptotics of quantum spins in a
coherent state.",0310027v1
2019-02-07,Polarization spin-tensors in two-spinor formalism and Behrends-Fronsdal spin projection operator for $D$-dimensional case,"In the work, the recurrent differential relations that connecting the
polarization spin-tensor of the wave function of a free massive particle of an
arbitrary spin for $D=4$ and new formula of the $D$-dimensional
Behrends-Fronsdal spin projection operator are found.",1902.02570v1
2010-02-16,Electron-doping evolution of the low-energy spin excitations in the iron arsenide BaFe$_{2-x}$Ni$_{x}$As$_{2}$ superconductors,"We use elastic and inelastic neutron scattering to systematically investigate
the evolution of the low-energy spin excitations of the iron arsenide
superconductor BaFe2-xNixAs2 as a function of nickel doping x. In the undoped
state, BaFe2As2 exhibits a tetragonal-to-orthorhombic structural phase
transition and simultaneously develops a collinear antiferromagnetic (AF) order
below TN = 143 K. Upon electron-doping of x = 0.075 to induce bulk
superconductivity with Tc = 12.3 K, the AF ordering temperature reduces to TN =
58 K.We show that the appearance of bulk superconductivity in
BaFe1.925Ni0.075As2 coincides with a dispersive neutron spin resonance in the
spin excitation spectra, and a reduction in the static ordered moment. For
optimally doped BaFe1.9Ni0.1As2 (Tc = 20 K) and overdoped BaFe1.85Ni0.15As2 (Tc
= 15 K) superconductors, the static AF long-range order is completely
suppressed and the spin excitation spectra are dominated by a resonance and
spin-gap at lower energies. We determine the electron-doping dependence of the
neutron spin resonance and spin gap energies, and demonstrate that the
three-dimensional nature of the resonance survives into the overdoped regime.
If spin excitations are important for superconductivity, these results would
suggest that the three-dimensional character of the electronic superconducting
gaps are prevalent throughout the phase diagram, and may be critical for
superconductivity in these materials.",1002.3133v2
2013-01-14,"Spin-flip Raman scattering of the neutral and charged excitons confined in a CdTe/(Cd,Mg)Te quantum well","Spin-flip Raman scattering of electrons and heavy-holes is studied for
resonant excitation of neutral and charged excitons in a
CdTe/Cd$_{0.63}$Mg$_{0.37}$Te quantum well. The spin-flip scattering is
characterized by its dependence on the incident and scattered light
polarization as well as on the magnetic field strength and orientation. Model
schemes of electric-dipole allowed spin-flip Raman processes in the exciton
complexes are compared to the experimental observations, from which we find
that lowering of the exciton symmetry, time of carrier spin relaxation, and
mixing between electron states and, respectively, light- and heavy-hole states
play an essential role in the scattering. At the exciton resonance, anisotropic
exchange interaction induces heavy-hole spin-flip scattering, while acoustic
phonon interaction is mainly responsible for the electron spin-flip. In
resonance with the positively and negatively charged excitons, anisotropic
electron-hole exchange as well as mixed electron states allow spin-flip
scattering. Variations in the resonant excitation energy and lattice
temperature demonstrate that localization of resident electrons and holes
controls the Raman process probability and is also responsible for symmetry
reduction. We show that the intensity of the electron spin-flip scattering is
strongly affected by the lifetime of the exciton complex and in tilted magnetic
fields by the angular dependence of the anisotropic electron-hole exchange
interaction.",1301.3108v2
2013-06-19,"Asymmetric Ferromagnetic Resonance, Universal Walker Breakdown, and Counterflow Domain Wall Motion in the Presence of Multiple Spin-Orbit Torques","We study the motion of several types of domain wall profiles in spin-orbit
coupled magnetic nanowires and also the influence of spin-orbit interaction on
the ferromagnetic resonance of uniform magnetic films. We extend previous
studies by fully considering not only the field-like contribution from the
spin-orbit torque, but also the recently derived Slonczewski-like spin-orbit
torque. We show that the latter interaction affects both the domain wall
velocity and the Walker breakdown threshold non-trivially, which suggests that
it should be accounted in experimental data analysis. We find that the presence
of multiple spin-orbit torques may render the Walker breakdown to be universal
in the sense that the threshold is completely independent on the
material-dependent Gilbert damping, non-adiabaticity, and the chirality of the
domain wall. We also find that domain wall motion against the current injection
is sustained in the presence of multiple spin-orbit torques and that the wall
profile will determine the qualitative influence of these different types of
torques (e.g. field-like and Slonczewski-like). In addition, we consider a
uniform ferromagnetic layer under a current bias, and find that the resonance
frequency becomes asymmetric against the current direction in the presence of
Slonczewski-like spin-orbit coupling. This is in contrast with those cases
where such an interaction is absent, where the frequency is found to be
symmetric with respect to the current direction. This finding shows that
spin-orbit interactions may offer additional control over pumped and absorbed
energy in a ferromagnetic resonance setup by manipulating the injected current
direction.",1306.4680v1
2016-05-13,Experimental elucidation of the origin of the `double spin resonances' in Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$,"We report a combined study of the spin resonances and superconducting gaps
for underdoped ($T_c=19$ K), optimally doped ($T_c=25$ K), and overdoped
($T_c=19$ K) Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ single crystals with inelastic
neutron scattering and angle resolved photoemission spectroscopy. We find a
quasi two dimensional spin resonance whose energy scales with the
superconducting gap in all three compounds. In addition, anisotropic low energy
spin excitation enhancements in the superconducting state have been deduced and
characterized for the under and optimally doped compounds. Our data suggest
that the quasi two dimensional spin resonance is a spin exciton that
corresponds to the spin singlet-triplet excitations of the itinerant electrons.
However, the intensity enhancements of the anisotropic spin excitations are
dominated by the out-of-plane spin excitations of the ordered moments due to
the suppression of damping in the superconducting state. Hence we offer a new
interpretation of the double energy scales differing from previous
interpretations based on anisotropic superconducting energy gaps, and
systematically explain the doping-dependent trend across the phase diagram.",1605.04257v2
2017-11-13,Spin properties of dense near-surface ensembles of nitrogen-vacancy centres in diamond,"We present a study of the spin properties of dense layers of near-surface
nitrogen-vacancy (NV) centres in diamond created by nitrogen ion implantation.
The optically detected magnetic resonance contrast and linewidth, spin
coherence time, and spin relaxation time, are measured as a function of
implantation energy, dose, annealing temperature and surface treatment. To
track the presence of damage and surface-related spin defects, we perform in
situ electron spin resonance spectroscopy through both double electron-electron
resonance and cross-relaxation spectroscopy on the NV centres. We find that,
for the energy ($4-30$~keV) and dose ($5\times10^{11}-10^{13}$~ions/cm$^2$)
ranges considered, the NV spin properties are mainly governed by the dose via
residual implantation-induced paramagnetic defects, but that the resulting
magnetic sensitivity is essentially independent of both dose and energy. We
then show that the magnetic sensitivity is significantly improved by
high-temperature annealing at $\geq1100^\circ$C. Moreover, the spin properties
are not significantly affected by oxygen annealing, apart from the spin
relaxation time, which is dramatically decreased. Finally, the average NV depth
is determined by nuclear magnetic resonance measurements, giving
$\approx10$-17~nm at 4-6 keV implantation energy. This study sheds light on the
optimal conditions to create dense layers of near-surface NV centres for
high-sensitivity sensing and imaging applications.",1711.04429v2
2019-06-02,Optical spin locking of a solid-state qubit,"Quantum control of solid-state spin qubits typically involves pulses in the
microwave domain, drawing from the well-developed toolbox of magnetic resonance
spectroscopy. Driving a solid-state spin by optical means offers a high-speed
alternative, which in the presence of limited spin coherence makes it the
preferred approach for high-fidelity quantum control. Bringing the full
versatility of magnetic spin resonance to the optical domain requires full
phase and amplitude control of the optical fields. Here, we imprint a
programmable microwave sequence onto a laser field and perform electron spin
resonance in a semiconductor quantum dot via a two-photon Raman process. We
show that this approach yields full SU(2) spin control with over 98%
pi-rotation fidelity. We then demonstrate its versatility by implementing a
particular multi-axis control sequence, known as spin locking. Combined with
electron-nuclear Hartmann-Hahn resonances which we also report in this work,
this sequence will enable efficient coherent transfer of a quantum state from
the electron spin to the mesoscopic nuclear ensemble.",1906.00427v2
2020-05-28,Spin-Pumping-Induced Non-Linear Electric Current on the Surface of a Ferromagnetic Topological Insulator,"We investigate the spin-pumping-induced electric current on the surface of a
three-dimensional topological insulator hybridized with a ferromagnet, namely,
ferromagnetic topological insulator. In order to do this, we establish the
microscopic formalism and construct the perturbation theory using a Keldysh
Green's function approach. We analyze how this electric current is generated by
an exchange interaction and an external ac magnetic field, which is the driving
force of ferromagnetic resonance as well as the spin pumping. The mechanism is
as follows. First, the ferromagnetic resonance is driven and a zero-momentum
magnon emerges. It is the fluctuation from the saturation magnetization
pointing parallel to the precession axis of the ferromagnetic resonance. After
then, the spin pumping is generated with the zero-momentum magnon being the
carrier of spin. The zero-momentum magnon and the topological insulator surface
state couples through the exchange interaction and the spin carried by the
magnon is transferred to it. Owing to the spin-momentum locking, the
transferred spin is converted into the momentum of topological insulator
surface state leading to the generation of electric current flowing
perpendicular to the precession axis of the ferromagnetic resonance. It is
quadratic in the amplitude of external ac magnetic field whereas it is linear
to the strength of the exchange interaction. The associated electric voltage is
described by the spectrum of zero-momentum magnon. The non-linearity of
spin-pumping-induced electric current in the ac magnetic field as well as the
linearity in the exchange-interaction strength reflects that the surface of
ferromagnetic topological insulator has a high-performing functionality of
generating the electric charge current by magnetic controlling.",2005.13850v1
2020-10-19,The spin-spin model and the capture into the double synchronous resonance,"The aim of this article is to propose a model, that is a planar version of
the Full Two-Body Problem, and discuss the existence and stability of a
relevant periodic solution. Consider two homogeneous ellipsoids orbiting around
each other in fixed coplanar Keplerian orbits. Moreover, their respective spin
axes are assumed to be perpendicular to the orbital plane, that is also a
common equatorial plane. The spin-spin model deals with the coupled rotational
dynamics of both ellipsoids. For a non-zero orbital eccentricity, it has the
structure of a non-autonomous system of coupled pendula. This model is a
natural extension of the classical spin-orbit problem for two extended bodies.
In addition, we consider dissipative tidal torques, that can trigger the
capture of the system into spin-orbit and spin-spin resonances. In this paper
we give some theoretical results for both the conservative model and the
dissipative one. The conservative model has a Hamiltonian structure. We use
properties of Hamiltonian systems to give some sufficient conditions in the
space of parameters of the model, that guarantee existence, uniqueness and
linear stability of an odd periodic solution. This solution represents a double
synchronous resonance in the conservative regime. Such solution can be
continued to the dissipative regime, where it becomes asymptotically stable. We
see asymptotic stability as a dynamical mechanism for the capture into the
double synchronous resonance. Finally we apply our results to several cases
including the Pluto-Charon binary system and the Trojan binary asteroid 617
Patroclus, target of the LUCY mission.",2010.09354v1
2001-01-06,Electron and Nuclear Spin Dynamics in Antiferromagnetic Molecular Rings,"We study theoretically the spin dynamics of the ferric wheel, an
antiferromagnetic molecular ring. For a single nuclear or impurity spin coupled
to one of the electron spins of the ring, we calculate nuclear and electronic
spin correlation functions and show that nuclear magnetic resonance (NMR) and
electron spin resonance (ESR) techniques can be used to detect coherent
tunneling of the Neel vector in these rings. The location of the NMR/ESR
resonances gives the tunnel splitting and its linewidth an upper bound on the
decoherence rate of the electron spin dynamics. We illustrate the experimental
feasibility of our proposal with estimates for Fe_10 molecules.",0101073v2
2001-07-11,Experimental evidence of the spin selection rule in KLL Auger transition,"With on- and off- resonant excitation photons, spin-resolved Auger electron
spectra of epitaxial CrO$_{2}$ thin films show an experimental evidence of the
spin-selective KLL Auger decay. The on-resonance O KLL Auger electrons are
found to be highly spin-polarized, while the off-resonance ones with almost
zero spin polarization. These results lead to conclude that the two-hole final
state in KLL Auger decay is a spin-singlet. Applications to spin-resolved
absorption spectroscopy are discussed.",0107234v2
2003-05-01,Spin effects and baryon resonance dynamics in phi-meson photoproduction at few GeV,"The diffractive $\phi$-meson photoproduction amplitude is dominated by the
Pomeron exchange process and contains the terms that govern the spin-spin and
spin-orbital interactions.
  We show that these terms are responsible for the spin-flip transitions at
forward photoproduction angles and appear in the angular distributions of
$\phi\to K^+K^-$ -decay in reactions with unpolarized and polarized photon
beams.
  At large momentum transfers, the main contribution to the $\phi$-meson
photoproduction is found to be due to the excitation of nucleon resonances.
  Combined analysis of $\omega$ and $\phi$ photoproduction indicates strong
OZI-rule violation in $\phi NN^*$ - couplings.
  We also show that the spin observables are sensitive to the dynamics of
$\phi$-meson photoproduction at large angles and could help distinguish
different theoretical models of nucleon resonances.
  Predictions for spin effects in $\phi$-meson photoproduction are presented
for future experimental tests.",0305002v2
2008-08-14,Co-resonant enhancement of spin-torque critical currents in spin-valves with synthetic-ferrimagnet free-layer,"It is experimentally shown that the critical current for onset of spin-torque
instability in current-perpendicular-to-plane spin-valves can be strongly
enhanced using ""synthetic ferrimagnet"" free-layers of form FM1/Ru/FM2
(FM=ferrromagnet). However, this enhancement occurs for only one polarity of
bias current. A two-macrospin model is shown to reproduce the observations. The
model suggests that this phenomenon is related to a polarity-dependent,
spin-torque induced co-resonance between the two natural dynamic modes of the
FM1/FM2 couple. The resonance condition facilitates energy transfer out of the
spin-torque destabilized mode into the other stable mode whose effective
damping is actually enhanced by spin-torques, thereby delaying the onset of
instability of this coupled system to larger critical currents.",0808.2015v2
2009-12-18,Stochastic resonance of a nanomagnet excited by spin transfer torque,"Spin transfer torque from spin-polarized electrical current can excite
large-amplitude magnetization dynamics in metallic ferromagnets of nanoscale
dimensions. Since magnetic anisotropy energies of nanomagnets are comparable to
the thermal energy scale, temperature can have a profound effect on the
dynamics of a nanomagnet driven by spin transfer torque. Here we report the
observation of unusual types of microwave-frequency nonlinear magnetization
dynamics co-excited by alternating spin transfer torque and thermal
fluctuations. In these dynamics, temperature amplifies the amplitude of
GHz-range precession of magnetization and enables excitation of highly
nonlinear dynamical states of magnetization by weak alternating spin transfer
torque. We explain these thermally activated dynamics in terms of non-adiabatic
stochastic resonance of magnetization driven by spin transfer torque. This type
of magnetic stochastic resonance may find use in sensitive nanometer-scale
microwave signal detectors.",0912.3842v1
2011-05-17,Magnetic Resonance Force Microscopy of paramagnetic electron spins at millikelvin temperatures,"Magnetic Resonance Force Microscopy (MRFM) is a powerful technique to detect
a small number of spins that relies on force-detection by an ultrasoft
magnetically tipped cantilever and selective magnetic resonance manipulation of
the spins. MRFM would greatly benefit from ultralow temperature operation,
because of lower thermomechanical noise and increased thermal spin
polarization. Here, we demonstrate MRFM operation at temperatures as low as 30
mK, thanks to a recently developed SQUID-based cantilever detection technique
which avoids cantilever overheating. In our experiment, we detect dangling bond
paramagnetic centers on a silicon surface down to millikelvin temperatures.
Fluctuations of such kind of defects are supposedly linked to 1/f magnetic
noise and decoherence in SQUIDs as well as in several superconducting and
single spin qubits. We find evidence that spin diffusion plays a key role in
the low temperature spin dynamics.",1105.3395v3
2012-08-27,Probing dynamics of an electron-spin ensemble via a superconducting resonator,"We study spin relaxation and diffusion in an electron-spin ensemble of
nitrogen impurities in diamond at low temperature (0.25-1.2 K) and polarizing
magnetic field (80-300 mT). Measurements exploit mode- and
temperature-dependent coupling of hyperfine-split sub-ensembles to the
resonator. Temperature-independent spin linewidth and relaxation time suggest
that spin diffusion limits spin relaxation. Depolarization of one sub-ensemble
by resonant pumping of another indicates fast cross-relaxation compared to spin
diffusion, with implications on use of sub-ensembles as independent quantum
memories.",1208.5473v1
2012-10-23,Spatial distribution of dynamically polarized nuclear spins in electron spin domains in the $ν= 2/3$ fractional quantum Hall state studied by nuclear electric resonance,"Nuclear electric resonance (NER) is based on nuclear magnetic resonance
mediated by spatial oscillations of electron spin domains excited by a radio
frequency (RF) electric field, and it allows us to investigate the spatial
distribution of the nuclear spin polarization around domain walls (DWs). Here,
NER measurements were made of the dynamic nuclear spin polarization (DNP) at
the spin phase transition of the fractional quantum Hall state at a Landau
level filling factor of $\nu=2/3$. From the RF pulse power and pulse duration
dependence of the NER spectrum, we show that the DNP occurs only within $\sim
100$ nm around DWs, and that it does not occur in DWs. We also show that DWs
are pinned by the hyperfine field from polarized nuclear spins.",1210.6223v2
2013-02-07,Scheme for a spin-based quantum computer employing induction detection and imaging,"A theoretical spin-based scheme for performing a variety of quantum
computations is presented. It makes use of an array of multiple identical
computer vectors of phosphorus-doped silicon where the nuclei serve as logical
qubits and the electrons as working qubits. The spins are addressed by a
combination of electron spin resonance and nuclear magnetic resonance
techniques operating at a field of ~3.3 T and cryogenic temperatures with an
ultra-sensitive surface microresonator. Spin initialization is invoked by a
combination of strong pre-polarization fields and laser pulses, which shortens
the electrons' T1. The set of universal quantum gates for this system includes
an arbitrary rotation of single qubits and c-NOT operation in two qubits. The
efficient parallel readout of all the spins in the system is performed by high
sensitivity induction detection of the electron spin resonance signals with
one-dimensional imaging. Details of the suggested scheme are provided, which
show that it is scalable to a few hundreds of qubits.",1302.1653v1
2013-07-15,Time Constants of Spin-Dependent Recombination Processes,"We present experiments to systematically study the time constants of
spin-dependent recombination processes in semiconductors using pulsed
electrically detected magnetic resonance (EDMR). The combination of
time-programmed optical excitation and pulsed spin manipulation allows us to
directly measure the recombination time constants of electrons via localized
spin pairs and the time constant of spin pair formation as a function of the
optical excitation intensity. Using electron nuclear double resonance, we show
that the time constant of spin pair formation is determined by an electron
capture process. Based on these time constants we devise a set of rate
equations to calculate the current transient after a resonant microwave pulse
and compare the results with experimental data. Finally, we critically discuss
the effects of different boxcar integration time intervals typically used to
analyze pulsed EDMR experiments on the determination of the time constants. The
experiments are performed on phosphorus-doped silicon, where EDMR via spin
pairs formed by phosphorus donors and Si/SiO2 interface dangling bond defects
is detected.",1307.4039v1
2014-05-27,Anisotropy of the molecular magnet V$_{15}$ spin Hamiltonian detected by high-field electron spin resonance,"The molecular compound K$_6$[V$^{IV}_{15}$As$^{III}_6$O$_{42}$(H$_2$O)]
$\cdot$ 8H$_2$O, in short V$_{15}$, has shown important quantum effects such as
coherent spin oscillations. The details of the spin quantum dynamics depend on
the exact form of the spin Hamiltonian. In this study, we present a precise
analysis of the intramolecular interactions in V$_{15}$. To that purpose, we
performed high-field electron spin resonance measurements at 120 GHz and
extracted the resonance fields as a function of crystal orientation and
temperature. The data are compared against simulations using exact
diagonalization to obtain the parameters of the molecular spin Hamiltonian.",1405.7000v1
2015-03-23,Highly selective detection of individual nuclear spins using the rotary echo on an electron spin as a probe,"We consider an electronic spin, such as a nitrogen-vacancy (NV) center in
diamond, weakly coupled to a large number (bath) of nuclear spins, and
subjected to the Rabi driving with a periodically alternating phase (multiple
rotary echo). We show that by switching the driving phase synchronously with
the precession of a given nuclear spin, the interaction to this spin is
selectively enhanced, while the rest of the bath remains decoupled. The
enhancement is of resonant character. The key feature of the suggested scheme
is that the width of the resonance is adjustable, and can be greatly decreased
by increasing the driving strength. Thus, the resonance can be significantly
narrowed, by a factor of 10--100 in comparison with the existing detection
methods. Significant improvement in selectivity is explained analytically and
confirmed by direct numerical many-spin simulations. The method can be applied
to a wide range of solid-state systems.",1503.06811v1
2015-05-28,Driving and detecting ferromagnetic resonance in insulators with the spin Hall effect,"We demonstrate the generation and detection of spin-torque ferromagnetic
resonance in Pt/YIG bilayers. A unique attribute of this system is that the
spin Hall effect lies at the heart of both the generation and detection
processes and no charge current is passing through the insulating magnetic
layer. When the YIG undergoes resonance, a dc voltage is detected
longitudinally along the Pt that can be described by two components. One is the
mixing of the spin Hall magnetoresistance with the microwave current. The other
results from spin pumping into the Pt being converted to a dc current through
the inverse spin Hall effect. The voltage is measured with applied magnetic
field directions that range in-plane to nearly perpendicular. We find that for
magnetic fields that are mostly out-of-plane, an imaginary component of the
spin mixing conductance is required to model our data.",1505.07791v1
2015-08-06,Interface-driven spin-torque ferromagnetic resonance by Rashba coupling at the interface between non-magnetic materials,"The Rashba-Edelstein effect stems from the interaction between the electron's
spin and its momentum induced by spin-orbit interaction at an interface or a
surface. It was shown that the inverse Rashba-Edelstein effect can be used to
convert a spin- into a charge current. Here, we demonstrate that a Bi/Ag Rashba
interface can even drive an adjacent ferromagnet to resonance. We employ a
spin-torque ferromagnetic resonance excitation/detection scheme which was
developed originally for a bulk spin-orbital effect, the spin Hall effect. In
our experiment, the direct Rashba-Edelstein effect generates an oscillating
spin current from an alternating charge current driving the magnetization
precession in a neighboring permalloy (Py, Ni80Fe20) layer. Electrical
detection of the magnetization dynamics is achieved by a rectification
mechanism of the time dependent multilayer resistance arising from the
anisotropic magnetoresistance.",1508.01410v1
2015-10-19,Atomic-like spin noise in solid-state demonstrated with manganese in cadmium telluride,"Spin noise spectroscopy is an optical technique which can probe spin
resonances non-perturbatively. First applied to atomic vapours, it revealed
detailed information about nuclear magnetism and the hyperfine interaction. In
solids, this approach has been limited to carriers in semiconductor
heterostructures. Here we show that atomic-like spin fluctuations of Mn ions
diluted in CdT e (bulk and quantum wells) can be detected through the Kerr
rotation associated to excitonic transitions. Zeeman transitions within and
between hyperfine multiplets are clearly observed in zero and small magnetic
fields and reveal the local symmetry because of crystal field and strain. The
linewidths of these resonances are close to the dipolar limit. The sensitivity
is high enough to open the way towards the detection of a few spins in systems
where the decoherence due to nuclear spins can be suppressed by isotopic
enrichment, and towards spin resonance microscopy with important applications
in biology and materials science.",1510.05885v1
2017-09-17,Intrinsic spin-orbit coupling gap and the evidence of a topological state in graphene,"In 2005 Kane & Mele[C. L. Kane and E. J. Mele, Phys. Rev. Lett. 95, 226801
(2005)], predicted that at sufficiently low energy, graphene exhibits a
topological state of matter with an energy gap generated by the atomic
spin-orbit interaction. However, this intrinsic gap has not been measured to
this date. In this letter, we exploit the chirality of the low energy states to
resolve this gap. We probe the spin states experimentally, by employing low
temperature microwave excitation in a resistively detected electron spin
resonance on graphene. The structure of the topological bands is reflected in
our transport experiments, where our numerical models allow us to identify the
resonance signatures. We determine the intrinsic spin-orbit bulk gap to be
exactly 42.2 {\mu}eV. Electron-spin resonance experiments can reveal the
competition between the intrinsic spin-orbit coupling and classical Zeeman
energy that arises at low magnetic fields and demonstrate that graphene remains
to be a material with surprising properties.",1709.05705v2
2017-03-20,Imaging the Real Space Structure of the Spin Fluctuations in an Iron-based superconductor,"Spin fluctuations are a leading candidate for the pairing mechanism in high
temperature superconductors, supported by the common appearance of a distinct
resonance in the spin susceptibility across the cuprates, iron-based
superconductors and many heavy fermion materials. The information we have about
the spin resonance comes almost exclusively from neutron scattering. Here we
demonstrate that by using low-temperature scanning tunnelling microscopy and
spectroscopy we can characterize the spin resonance in real space. We show that
inelastic tunnelling leads to the characteristic dip-hump feature seen in
tunnelling spectra in high temperature superconductors and that this feature
arises from excitations of the spin fluctuations. Spatial mapping of this
feature near defects allows us to probe non-local properties of the spin
susceptibility and to image its real space structure.",1703.07002v2
2021-03-31,Room temperature antiferromagnetic resonance and inverse spin-Hall voltage in canted antiferromagnets,"We study theoretically and experimentally the spin pumping signals induced by
the resonance of canted antiferromagnets with Dzyaloshinskii-Moriya interaction
and demonstrate that they can generate easily observable inverse spin-Hall
voltages. Using a bilayer of hematite/heavy metal as a model system, we measure
at room temperature the antiferromagnetic resonance and an associated inverse
spin-Hall voltage, as large as in collinear antiferromagnets. As expected for
coherent spin-pumping, we observe that the sign of the inverse spin-Hall
voltage provides direct information about the mode handedness as deduced by
comparing hematite, chromium oxide and the ferrimagnet Yttrium-Iron Garnet. Our
results open new means to generate and detect spin-currents at terahertz
frequencies by functionalizing antiferromagnets with low damping and canted
moments.",2103.16872v1
2021-12-29,Multiorbital spin-triplet pairing and spin resonance in the heavy-fermion superconductor $\mathrm{UTe_2}$,"The heavy-fermion system $\mathrm{UTe_2}$ is a candidate for spin-triplet
superconductivity, which is of considerable interest to quantum engineering.
Among the outstanding issues is the nature of the pairing state. A recent
surprising discovery is the observation of a resonance in the spin excitation
spectrum at an antiferromagnetic wavevector [C. Duan {\it et al.}, Nature
\textbf{600}, 636 (2021)], which stands in apparent contrast to the
ferromagnetic nature of the interactions expected in this system. We show how
the puzzle can be resolved by a multiorbital spin-triplet pairing constructed
from local degrees of freedom. Because it does not commute with the kinetic
part of the Hamiltonian, the pairing contains both intra- and inter-band terms
in the band basis. We demonstrate that the intraband pairing component
naturally yields a spin resonance at the antiferromagnetic wavevector. Our work
illustrates how orbital degrees of freedom can enrich the nature and properties
of spin-triplet superconductivity of strongly-correlated quantum materials.",2112.14750v1
2022-06-12,Interference phenomena in Josephson junctions with ferromagnetic bilayers: Spin-triplet correlations and resonances,"We study the Josephson effect in planar $SF_1F_2S$ junctions that consist of
conventional $s$-wave superconductors ($S$) connected by two metallic
monodomain ferromagnets ($F_1$ and $F_2$) with arbitrary transparency of
interfaces. We solve the scattering problem in the clean limit based on the
Bogoliubov-de Gennes equation for both spin-singlet and odd in frequency
spin-triplet pairing correlations. We calculate numerically the Josephson
current-phase relation $I(\phi)$. While the first harmonic of $I(\phi)$ is
completely generated by spin-singlet and short-range spin-triplet
superconducting correlations, for noncollinear magnetizations of ferromagnetic
layers the second harmonic has an additional long-range spin-triplet component.
Therefore, for strong ferromagnetic influence, the long-range spin-triplet
contribution to the second harmonic dominates. We find an exception due to the
geometric resonance for equal ferromagnetic layers when the first harmonic is
strongly enhanced. Both first and second harmonic amplitudes oscillate with
ferromagnetic layer thicknesses due to $0-\pi$ transitions. We study the
influence of interface transparencies and find additional resonances for finite
transparency of interface between ferromagnetic layers.",2206.05770v3
2022-11-17,Stable Atomic Magnetometer in Parity-Time Symmetry Broken Phase,"Random motion of spins is usually detrimental in magnetic resonance
experiments. The spin diffusion in non-uniform magnetic fields causes
broadening of the resonance and limits the sensitivity and the spectral
resolution in applications like magnetic resonance spectroscopy. Here, by
observation of the parity-time ($PT$) phase transition of diffusive spins in
gradient magnetic fields, we show that the spatial degrees of freedom of atoms
could become a resource, rather than harmfulness, for high-precision
measurement of weak signals. In the normal phase with zero or low gradient
fields, the diffusion results in dissipation of spin precession. However, by
increasing the field gradient, the spin system undergoes a $PT$ transition, and
enters the $PT$ symmetry broken phase. In this novel phase, the spin precession
frequency splits due to spatial localization of the eigenmodes. We demonstrate
that, using these spatial-motion-induced split frequencies, the spin system can
serve as a stable magnetometer, whose output is insensitive to the inevitable
long-term drift of control parameters. This opens a door to detect extremely
weak signals in imperfectly controlled environment.",2211.09354v1
2023-06-27,Spin-Polarized Photoelectrons in the Vicinity of Spectral Features,"We investigate the spin polarization of photoelectrons emitted from noble
gases, in the vicinity of spectral features such as Fano resonances, Cooper
minima, and giant resonances. Since these features all exhibit spatio-spectral
coupling, they are intrinsically linked to the spin polarization through the
spin-orbit coupling.
  In contrast to c{\ae}sium, as originally proposed by Fano (1969)
https://doi.org/10.1103/PhysRev.178.131, the rare gases do not provide large
spin polarization in the vicinity of the Cooper minimum. However, the Fano
resonances yield much higher spin polarization ($\ge40\%$). Furthermore, if the
photoelectron is measured in coincidence with the photoion, 100\% spin
polarization is possible, also close to the Cooper minimum.",2306.15665v1
2023-07-23,Programmable Quantum Processors based on Spin Qubits with Mechanically-Mediated Interactions and Transport,"Solid state spin qubits are promising candidates for quantum information
processing, but controlled interactions and entanglement in large, multi-qubit
systems are currently difficult to achieve. We describe a method for
programmable control of multi-qubit spin systems, in which individual
nitrogen-vacancy (NV) centers in diamond nanopillars are coupled to
magnetically functionalized silicon nitride mechanical resonators in a scanning
probe configuration. Qubits can be entangled via interactions with
nanomechanical resonators while programmable connectivity is realized via
mechanical transport of qubits in nanopillars. To demonstrate the feasibility
of this approach, we characterize both the mechanical properties and the
magnetic field gradients around the micromagnet placed on the nanobeam
resonator. Furthermore, we show coherent manipulation and mechanical transport
of a proximal spin qubit by utilizing nuclear spin memory, and use the NV
center to detect the time-varying magnetic field from the oscillating
micromagnet, extracting a spin-mechanical coupling of 7.7(9) Hz. With realistic
improvements the high-cooperativity regime can be reached, offering a new
avenue towards scalable quantum information processing with spin qubits.",2307.12193v1
2002-06-21,Novel excitonic states in quantum Hall systems: Bound states of spin waves and a valence band hole,"If the Zeeman energy is small, the lowest energy excitations of a two
dimensional electron gas at filling factor nu=1 are spin waves (spin flip
excitations). At nu slightly larger (smaller) than unity, reversed spin
electrons (spin holes) can form bound states with K spin waves that are known
as skyrmions, S_K^- (antiskyrmions, S_K^+). It is suggested in this work that a
valence hole can also bind K spin waves to form an excitonic complex X_K^+,
analogous to the S_K^+. One spin hole of the S_K^+ is simply replaced by the
valence hole. At nu<=1, a small number of S_K^+'s are present before
introduction of the valence hole. The (S_K^+)-(X_K^+) repulsion leads to
correlations and photoluminescence similar to those of a dilute
electron-(charged-exciton) (e-X^-) system at nu<=1/3. At nu>=1, the
(S_K^-)-(X_K^+) attraction can potentially lead to different behavior.",0206413v1
2010-07-31,Random walk approach to spin dynamics in a two-dimensional electron gas with spin-orbit coupling,"We introduce and solve a semi-classical random walk (RW) model that describes
the dynamics of spin polarization waves in zinc-blende semiconductor quantum
wells. We derive the dispersion relations for these waves, including the
Rashba, linear and cubic Dresselhaus spin-orbit interactions, as well as the
effects of an electric field applied parallel to the spin polarization
wavevector. In agreement with fully quantum mechanical calculations [Kleinert
and Bryksin, Phys. Rev. B \textbf{76}, 205326 (2007)], the RW approach predicts
that spin waves acquire a phase velocity in the presence of the field that
crosses zero at a nonzero wavevector, $q_0$. In addition, we show that the
spin-wave decay rate is independent of field at $q_0$ but increases as
$(q-q_0)^2$ for $q\neq q_0$. These predictions can be tested experimentally by
suitable transient spin grating experiments.",1008.0132v2
2012-12-30,Edge spin excitations and reconstructions of integer quantum Hall liquids,"We study the effect of electron-electron interaction on the charge and spin
structures at the edge of integer quantum Hall liquids, under three different
kinds of confining potentials. Our exact diagonalization calculation for small
systems indicates that the low energy excitations of \nu=1 ferromagnetic state
are bosonic edge spin waves. Instabilities of the ferromagnetic state with
altering confinement strength result from the softening of these edge spin
waves, and formation of edge spin textures. In \nu\lesssim 2 regime, exact
diagonalization on edge electron systems indicates that compact Hartree-Fock
states with different total spin always become ground states in some regions of
parameter space, and the ground states appear in between two compact states are
their edge spin waves. The initial \nu=2 instability is toward the compact
state with total spin 1. Larger systems are studied using a microscopic trial
wave functions, and some quantitative predictions on the edge instabilities for
a certain type of confining potential are reached in the thermodynamic limit.",1212.6743v2
2014-12-09,Spin excitations in the nematic phase and the metallic stripe spin-density wave phase of iron pnictides,"We present a general study of the magnetic excitations within a weak-coupling
five-orbital model relevant to itinerant iron pnictides. As a function of
enhanced electronic correlations, the spin excitations in the symmetry broken
spin-density wave phase evolve from broad low-energy modes in the limit of weak
interactions to sharply dispersing spin wave prevailing to higher energies at
larger interaction strengths. We show how the resulting spin response at high
energies depends qualitatively on the magnitude of the interactions. We also
calculate the magnetic excitations in the nematic phase by including an orbital
splitting, and find a pronounced C_2 symmetric excitation spectrum right above
the transition to long-range magnetic order. Finally, we discuss the C_2 versus
C_4 symmetry of the spin excitations as a function of energy for both the
nematic and the spin-density wave phase.",1412.2912v1
2017-12-01,Spin waves and stability of zigzag order in the Hubbard model with spin-dependent hopping terms - Application to the honeycomb lattice compounds ${\rm Na_2 Ir O_3}$ and ${\rm α- Ru Cl_3}$,"Spin waves in the zigzag ordered state on a honeycomb lattice are
investigated within a Hubbard model with spin-dependent hopping terms. Roles of
the emergent Kitaev, Heisenberg, Dzyaloshinskii-Moriya, and
symmetric-off-diagonal spin interactions are investigated on the stability of
the zigzag order. While the DM interactions are found to destabilize the zigzag
order, the secondary spin-dependent hopping terms (associated with structural
distortions) are shown to strongly stabilize the zigzag order and account for
magnetocrystalline anisotropy, easy axis, and spin wave gap. The calculated
spin wave dispersion and energy scale are in good agreement with inelastic
neutron scattering measurements on $\rm \alpha - RuCl_3$ and $\rm Na_2 Ir O_3$.",1712.00198v2
2019-10-17,Optical storage for 0.53 seconds in a solid-state atomic frequency comb memory using dynamical decoupling,"Quantum memories with long storage times are key elements in long-distance
quantum networks. The atomic frequency comb (AFC) memory in particular has
shown great promise to fulfill this role, having demonstrated multimode
capacity and spin-photon quantum correlations. However, the memory storage
times have so-far been limited to about one millisecond, realized in a
Eu${}^{3+}$ doped Y${}_2$SiO${}_5$ crystal at zero applied magnetic field.
Motivated by studies showing increased spin coherence times under applied
magnetic field, we developed a AFC spin-wave memory utilizing a weak 15 mT
magnetic field in a specific direction that allows efficient optical and spin
manipulation for AFC memory operations. With this field configuration the AFC
spin-wave storage time increased to 40 ms using a simple spin-echo sequence.
Furthermore, by applying dynamical decoupling techniques the spin-wave
coherence time reaches 530 ms, a 300-fold increase with respect to previous AFC
spin-wave storage experiments. This result paves the way towards long duration
storage of quantum information in solid-state ensemble memories.",1910.08009v2
2023-07-25,Spin waves in bilayers of transition-metal dichalcogenides,"Van der Waals magnetic materials are currently of great interest as materials
for applications in future ultrathin nanoelectronics and nanospintronics. Due
to weak coupling between individual monolayers, these materials can be easily
obtained in the monolayer and bilayer forms. The latter are of specific
interest as they may be considered as natural two-dimensional spin valves. In
this paper, we study theoretically spin waves in bilayers of transition metal
dichalcogenides. The considerations are carried within the general spin wave
theory based on effective spin Hamiltonian and Hollstein-Primakoff-Bogolubov
transformation. The spin Hamiltonian includes intra-layer as well as
inter-layer nearest-neighbour exchange interactions, easy-plane anisotropy, and
additionally a weak in-plane easy-axis anisotropy. The bilayer systems consist
of two ferromagnetic (in-plane magnetization) monolayers that are coupled
either ferromagnetically or antiferromagnetically. In the latter case, we
analyse the spin wave spectra in all magnetic phases, i.e. in the
antiferromagnetic, spin-flop, and ferromagnetic ones.",2307.13414v2
2023-12-28,Collective spin oscillations in a magnetized graphene sheet,"We investigate collective spin excitations of graphene electrons with
short-ranged interactions and subject to the external Zeeman magnetic field. We
find that in addition to the familiar Silin spin wave, a collective spin-flip
excitation that reduces to the uniform precession when the wave's momentum
approaches zero, the magnetized graphene supports another collective mode
visible in the transverse spin susceptibility: a collective spin-current mode.
Unlike the Silin wave, this mode is not dictated by the spin-rotational
symmetry but rather owns its existence to the pseudo-spin structure of the
graphene lattice. We find the new collective excitation to become sharply
defined in a finite interval of wave's momenta, the range of which is
determined by the interaction and the magnetization.",2312.16782v1
2024-01-10,Electrical Non-Hermitian Control of Topological Magnon Spin Transport,"Magnonic topological phases realize chiral edge spin waves that are protected
against backscattering, potentially enabling highly efficient spin transport.
Here we show that the spin transport through these magnonic chiral edge states
can be electrically manipulated by non-Hermitian control. We consider the
paradigmatic magnon Haldane model and show that it is transformed into an
effective non-Hermitian magnon Chern insulator by including a
sublattice-dependent spin-orbit torque. In linear spin-wave theory, this
electrically induced torque causes a lasing of the chiral edge magnons along
certain edge directions, leading to an enhancement of the spin-wave amplitude.
This prediction is confirmed by numerical simulations based on the
Landau-Lifshitz-Gilbert equation. For a spin-wave transport setup, in which
magnons are excited by a microwave field and detected with a normal metal
conductor, we find that the magnon amplification is remarkably robust against
disorder, establishing non-Hermitian control as a promising avenue for
topological magnonics.",2401.04967v2
2005-12-06,Polarization transfer in pulsar magnetosphere,"Propagation of radio waves in the ultrarelativistic magnetized
electron-positron plasma of pulsar magnetosphere is considered. Polarization
state of the original natural waves is found to vary markedly on account of the
wave mode coupling and cyclotron absorption. The change is most pronounced when
the regions of mode coupling and cyclotron resonance approximately coincide. In
cases when the wave mode coupling occurs above and below the resonance region,
the resultant polarization appears essentially distinct. The main result of the
paper is that in the former case the polarization modes become non-orthogonal.
The analytical treatment of the equations of polarization transfer is
accompanied by the numerical calculations. The observational consequences of
polarization evolution in pulsar plasma are discussed as well.",0512140v1
1997-03-06,Partial-Wave Amplitudes and Resonances in pbar + p -> pi + pi,"Partial wave amplitudes have been extracted from accurate data on pbar + p ->
pi + pi by a method which incorporates the theoretical constraints of
analyticity and crossing symmetry. The resulting solution gives a good fit to
the annihilation data and is also consistent with the wealth of information in
the crossed channel pi + N -> pi + N. The partial wave amplitudes show evidence
for resonances in all partial waves with J < 6, at least one of which, a J = 0+
state, (and possibly another with J = 1-) is unlikely to have a simple
quark-antiquark structure.",9703253v1
2006-12-18,Application of Dressing Method for Long Wave-Short Wave Resonance Interaction Equation,"In this paper we investigate the application of Zakharov - Shabat dressing
method to (2+1) - dimensional long wave - short wave resonance interaction
equation (LSRI). Using this method we can construct the exact N - soliton
solution of this equation depending on arbitrary constants. It contains both
solutions which don't decay along N different directions in space infinity, and
""dromion"" ones, or localized solutions that decay exponentially in all
directions.",0612041v1
2000-11-15,Electromagnetic oscillations in periodic mediums outside the passbands,"It was usually assumed that the resonator based on a waveguide has the eigen
oscillations that are formed by interference of two waves which propagate in
different directions and have equal amplitudes. These patterns are usually
called standing waves. We have shown that the eigen oscillations of a resonator
which is filled by a layered dielectric can be base on the evanescent
(non-propagating) waves. In some cases we need only one eigen wave to compose
the eigen oscillation of a closed cavity.",0011028v2
2005-10-14,Nontrapping arrest of Langmuir wave damping near the threshold amplitude,"Evolution of a Langmuir wave is studied numerically for finite amplitudes
slightly above the threshold which separates damping from nondamping cases.
Arrest of linear damping is found to be a second-order effect due to ballistic
evolution of perturbations, resonant power transfer between field and
particles, and organization of phase space into a positive slope for the
average distribution function $f_{av}$ around the resonant wave phase speed
$v_\phi$. Near the threshold trapping in the wave potential does not arrest
damping or saturate the subsequent growth phase.",0510131v3
2009-11-27,Photoproduction of pions and properties of baryon resonances from a Bonn-Gatchina partial wave analysis,"Masses, widths and photocouplings of baryon resonances are determined in a
coupled-channel partial wave analysis of a large variety of data. The
Bonn-Gatchina partial wave formalism is extended to include a decomposition of
t- and u-exchange amplitudes into individual partial waves. The multipole
transition amplitudes for $\gamma p\to p\pi^0$ and $\gamma p\to n\pi^+$ are
given and compared to results from other analyses.",0911.5277v2
2010-10-21,Switchable metamaterial reflector/absorber for different polarized electromagnetic waves,"We demonstrate a controllable electromagnetic wave reflector/absorber for
different polarizations with metamaterial involving electromagnetic resonant
structures coupled with diodes. Through biasing at different voltages to turn
ON and OFF the diodes, we are able to switch the structure between nearly total
reflection and total absorption of a particularly polarized incident wave. By
arranging orthogonally orientated resonant cells, the metamaterial can react to
different polarized waves by selectively biasing the corresponding diodes. Both
numerical simulations and microwave measurements have verified the performance.",1010.4377v1
2011-10-11,Wave and Particle Limit for Multiple Barrier Tunneling,"The particle approach to one-dimensional potential scattering is applied to
non relativistic tunnelling between two, three and four identical barriers. We
demonstrate as expected that the infinite sum of particle contributions yield
the plane wave results. In particular, the existence of resonance/transparency
for twin tunnelling in the wave limit is immediately obvious. The known
resonances for three and four barriers are also derived. The transition from
the wave limit to the particle limit is exhibit numerically.",1110.2433v1
2012-06-09,Wood's anomalies and excitation of cyclic Sommerfeld resonances under plane wave scattering from a single dielectric cylinder at oblique incidence of light,"In this paper we consider a process of plane wave scattering from a single
dielectric cylinder at oblique incidence under which it is possible to excite
long range cyclic Sommerfeld waves (CSWs) and consequently cyclic Sommerfeld
resonances (CSRs) of different orders. It is shown that the CSRs are analogous
to Wood's anomalies occurred under plane wave scattering from one dimensional
(1D) metallic diffraction gratings. The conditions which are necessary for an
effective excitation of CSWs and CSRs with high quality factors are analyzed.",1206.1942v1
2012-12-22,Tunneling-induced high efficiency four-wave mixing in an asymmetric quantum wells,"An asymmetric double quantum wells (QWs) structure with resonant tunneling is
suggested to achieve high efficient four wave mixing (FWM). We analytically
demonstrate that the resonant tunneling can induce high efficient mixing wave
in such a semiconductor structure with a low light pump wave. In particular,
the FWM conversion efficiency can be enhanced dramatically in the vicinity of
the center frequency. This interesting scheme may be used to generate coherent
long-wavelength radiation in solid-state system.",1212.5699v1
2014-07-22,Compact infrared continuous-wave double-pass single-frequency doubly-resonant OPO,"We demonstrate a compact continuous-wave single-frequency doubly-resonant
optical parametric oscillator (DRO) in a double-pass pump configuration with a
control of the relative phase between the reflected waves. The nested DRO
cavity allows single longitudinal mode operation together with low threshold
and high efficiency. Thermal effects are managed by chopping the pump beam,
allowing continuous tuning of the emitted wavelength. The infrared idler wave
(3200-3800 nm) can be used for gas detection and the threshold pump power is
compatible with diode pumping.",1407.5867v1
2023-07-13,Landscape of wave focusing and localisation at low frequencies,"High-contrast scattering problems are special among classical wave systems as
they allow for strong wave focusing and localisation at low frequencies. We use
an asymptotic framework to develop a landscape theory for high-contrast systems
that resonate in a subwavelength regime. Our from-first-principles asymptotic
analysis yields a characterisation in terms of the generalised capacitance
matrix, giving a discrete approximation of the three-dimensional scattering
problem. We develop landscape theory for the generalised capacitance matrix and
use it to predict the positions of three-dimensional wave focusing and
localisation in random and non-periodic systems of subwavelength resonators.",2307.06729v2
2000-07-16,High frequency resonant experiments in Fe$_8$ molecular clusters,"Precise resonant experiments on Fe$_{8}$ magnetic clusters have been
conducted down to 1.2 K at various tranverse magnetic fields, using a
cylindrical resonator cavity with 40 different frequencies between 37 GHz and
110 GHz. All the observed resonances for both single crystal and oriented
powder, have been fitted by the eigenstates of the hamiltonian ${\cal
H}=-DS_z^2+ES_x^2-g\mu_B{\bf H}\cdot {\bf S}$. We have identified the
resonances corresponding to the coherent quantum oscillations for different
orientations of spin S = 10.",0007265v1
2008-02-25,Atomic hyperfine resonances in a magnetic quadrupole field,"The quantum resonances of an atom possessing a single valence electron which
shows hyperfine interaction with the nucleus is investigated in the presence of
a three dimensional magnetic quadrupole field. Particular emphasis is put on
the study of the interplay of the hyperfine and quadrupole forces. Analyzing
the underlying Hamiltonian a variety of symmetries are revealed which give rise
to a two-fold degeneracy of the resonance energies. Our numerical approach
employs the complex scaling method and a Sturmian basis set. Several regimes
and classes of short-lived and long-lived resonances are identified. The
energies and decay widths of the resonances are characterized by their
electronic and nuclear spin properties.",0802.3645v1
2008-12-17,Baryon resonances in the mean field approach and a simple explanation of the Theta+ pentaquark,"We suggest to classify baryon resonances as single-quark states in a mean
field, and/or as its collective excitations. Identifying the Roper resonance
N(1440), the nucleon resonance N(1535), and the singlet hyperon Lambda(1405) as
single-quark excitations, we find that there must be an exotic S=+1 baryon
resonance Theta+ (the ""pentaquark"") with a mass about 1440+1535-1405=1570 MeV
and spin-parity one-half-plus. We argue that Theta+ is an analog of the
Gamov--Teller excitation long known in nuclear physics.",0812.3418v1
2012-08-17,"Bayesian inference of the resonance content of p(gamma,K+)Lambda","A Bayesian analysis of the world's p(gamma,K+)Lambda data is presented. We
adopt a Regge-plus-resonance framework featuring consistent couplings for
nucleon resonances up to spin J=5/2, and evaluate 2048 model variants
considering all possible combinations of 11 candidate resonances. The best
model, labeled RPR-2011, is discussed with special emphasis on nucleon
resonances in the 1900-MeV mass region.",1208.3618v1
2013-10-12,Resonant dynamics of chromium condensates,"We numerically study the dynamics of a spinor chromium condensate in low
magnetic fields. We show that the condensate evolution has a resonant character
revealing rich structure of resonances similar to that already discussed in the
case of alkali-atoms condensates. This indicates that dipolar resonances occur
commonly in the systems of cold atoms. In fact, they have been already observed
experimentally. We further simulate two recent experiments with chromium
condensates, in which the threshold in spin relaxation and the spontaneous
demagnetization phenomena were observed. We demonstrate that both these effects
originate in resonant dynamics of chromium condensate.",1310.3384v1
2018-03-12,Probing unconventional superconductivity in proximitized graphene by impurity scattering,"We demonstrate how potential impurities are a very powerful tool for
determining the pairing symmetry in graphene proximity-coupled to a
spin-singlet superconductor. All d-wave states are characterized by subgap
resonances, with spatial patterns clearly distinguishing between nodal and
chiral d-wave symmetry, while s-wave states have no subgap resonances. We also
find strong supergap impurity resonances associated with the normal state Dirac
point. Sub- and supergap resonances only interact at very low doping levels,
then causing suppression of the supergap resonances.",1803.04455v2
2022-06-24,Meridional composite pulses for low-field magnetic resonance,"We discuss procedures for error-tolerant spin control in environments that
permit transient, large-angle reorientation of magnetic bias field. Short
sequences of pulsed, non-resonant magnetic field pulses in a laboratory-frame
meridional plane are derived. These are shown to have band-pass excitation
properties comparable to established amplitude-modulated, resonant pulses used
in high, static-field magnetic resonance. Using these meridional pulses, we
demonstrate robust $z$ inversion in proton ($^{1}$H) nuclear magnetic resonance
near earth's field.",2206.12025v1
1994-06-02,Inelastic Neutron Scattering from the Spin Ladder Compound (VO)2P2O7,"We present results from an inelastic neutron scattering experiment on the
candidate Heisenberg spin ladder vanadyl pyrophosphate, (VO)2P2O7. We find
evidence for a spin-wave excitation gap of $E_{gap} = 3.7\pm 0.2$ meV, at a
band minimum near $Q=0.8 A^{-1}$. This is consistent with expectations for
triplet spin waves in (VO)2P2O7 in the spin-ladder model, and is to our
knowledge the first confirmation in nature of a Heisenberg antiferromagnetic
spin ladder.",9406016v1
2002-01-31,The spin-1/2 Heisenberg antiferromagnet on a 1/7-depleted triangular lattice: Ground-state properties,"A linear spin-wave approach, a variational method and exact diagonlization
are used to investigate the magnetic long-range order (LRO) of the spin-1/2
Heisenberg antiferromagnet on a two-dimensional 1/7-depleted triangular (maple
leaf) lattice consisting of triangles and hexagons only. This lattice has z=5
nearest neighbors and its coordination number z is therefore between those of
the triangular (z=6) and the kagome (z=4) lattices. Calculating spin-spin
correlations, sublattice magnetization, spin stiffness, spin-wave velocity and
spin gap we find that the classical 6-sublattice LRO is strongly renormalized
by quantum fluctuations, however, remains stable also in the quantum model.",0201584v1
2004-07-06,Effect of Spin Current on Uniform Ferromagnetism: Domain Nucleation,"Large spin current applied to a uniform ferromagnet leads to a spin-wave
instability as pointed out recently.
  In this paper, it is shown that such spin-wave instability is absent in a
state containing a domain wall, which indicates that nucleation of magnetic
domains occurs above a certain critical spin current.
  This scenario is supported also by an explicit energy comparison of the two
states under spin current.",0407116v2
2005-10-20,Low-energy Effective Theory for Spin Dynamics of Fluctuating Stripes,"We derive an effective Hamiltonian for spin dynamics of fluctuating smectic
stripes from the t-J model in the weak coupling limit t >> J. Besides the
modulation of spin magnitude, the high energy hopping term would induce a
low-energy anti-ferromagnetic interaction between two neighboring ``blocks of
spins"". Based on the effective Hamiltonian, we applied the linear spin-wave
theory and found that the spin-wave velocity is almost isotropic for
La_{2-x}Sr_x CuO_4 unless the structural effect is considered. The intensity of
the second harmonic mode is found to be about 10% to that of the fundamental
mode.",0510529v1
2006-03-01,Stochastic theory of spin-transfer oscillator linewidths,"We present a stochastic theory of linewidths for magnetization oscillations
in spin-valve structures driven by spin-polarized currents. Starting from a
nonlinear oscillator model derived from spin-wave theory, we derive Langevin
equations for amplitude and phase fluctuations due to the presence of thermal
noise. We find that the spectral linewidths are inversely proportional to the
spin-wave intensities with a lower bound that is determined purely by
modulations in the oscillation frequencies. Reasonable quantitative agreement
with recent experimental results from spin-valve nanopillars is demonstrated.",0603019v1
2009-01-20,Role of Bound Magnon in Magnetic Domain Wall Motion,"We report on a quantum description of the domain wall (DW) motion under a
spin current. A bound magnon, which is the zero mode of DW, is found to play a
dominant role in DW dynamics. The bound magnon acquires its inertia by the hard
axis anisotropy and is a free particle even under the spin current. The full
transfer of spin angular momentum from the spin current to DW via the bound
magnon leads to the DW motion with the adiabatic velocity, decoupling of spin
waves from DW, and no Doppler shift in spin waves.",0901.3066v1
2009-03-24,A Finite-temperature First-principles Approach to Spin Fluctuation in BaFe_2As_2,"Thermodynamic flunctuations in BaFe2As2 is addressed with a first-principles
formulation of the Helmholtz energy by accounting for the mixture of various
electronic states each distinguished by different spin orientation
distributions. We find that it is the spin exchange coupling in the inter-plane
c direction that dictates the spin density wave ordering. We quantitatively
predicted the pressure dependence of the spin density wave ordering, the
Schottky anomaly, and the temperature dependence of thermal populations of spin
structures, all in agreement with available experimental data.",0903.4094v1
2010-05-27,Spin transport in coupled spinor Bose gases,"We report direct measurements of spin transport in a trapped, partially
condensed spinor Bose gas. Detailed analyses of spin flux in this
out-of-equilibrium quantum gas are performed by monitoring the flow of atoms in
different hyperfine spin states. The main mechanisms for motion in this system
are exchange scattering and potential energy inhomogeneity, which lead to spin
waves in the normal component and domain formation in the condensate. We find a
large discrepancy in domain formation timescales with those predicted by
potential-driven formation, indicating strong coupling of the condensate to the
normal component spin wave.",1005.5174v2
2012-07-28,Excitations and spin correlations near the interface of two three-dimensional Heisenberg antiferromagnets,"Magnetic excitations and spin correlations near the interface of two
spin-$\frac12$ Heisenberg antiferromagnets are considered using the spin-wave
approximation. When the interaction between boundary spins differs essentially
from exchange constants inside the antiferromagnets, quasi-two-dimensional spin
waves appear in the near-boundary region. They eject bulk magnons from this
region, thereby dividing the antiferromagnets into areas with different
magnetic excitations. The decreased dimensionality of the near-boundary modes
leads to amplified nearest-neighbor spin correlations in the interface area.",1207.6688v1
2012-11-16,Dependence of the Switching Current Density on the Junction Sizes in Spin Transfer Torque,"We investigate the dependence of switching current density on the junction
sizes in the spin transfer torque nanopillar structures by using micromagnetic
simulations. While the macro spin model predicts weak dependence of switching
current density on the junction sizes, we find that the switching current
density is a sensitive function of the junction sizes. It can be explained with
the complicated spin configurations and dynamics during the switching process.
The detail spin configurations and dynamics are determined by spin wave
excitation with the finite wave vector, which is related with the exchange
coupling energy and junction shape.",1211.3785v1
2013-12-04,Excitations and quasi-one-dimensionality in field-induced nematic and spin density wave states,"We study the excitation spectrum and dynamical response functions for several
quasi-one-dimensional spin systems in magnetic fields without dipolar spin
order transverse to the field. This includes both nematic phases, which harbor
""hidden"" breaking of spin-rotation symmetry about the field and have been
argued to occur in high fields in certain frustrated chain systems with
competing ferromagnetic and antiferromagnetic interactions, and spin density
wave states, in which spin-rotation symmetry is truly unbroken. Using
bosonization, field theory, and exact results on the integrable sine-Gordon
model, we establish the collective mode structure of these states, and show how
they can be distinguished experimentally.",1312.0992v1
2014-07-29,Spin-Hall Nano-oscillator: a micromagnetic study,"This letter studies the dynamical behavior of spin-Hall nanoscillators from a
micromagnetic point of view. The model parameters have been identified by
reproducing recent experimental data quantitatively. Our results indicate that
a strongly localized mode is observed for in-plane bias fields such as in the
experiments, while predict the excitation of an asymmetric propagating mode for
large enough out-of plane bias field similarly to what observed in spin-torque
nanocontact oscillators. Our findings show that spin-Hall nanoscillators can
find application as spin-wave emitters for magnonic applications where spin
waves are used for transmission and processing information on nanoscale.",1407.7655v1
2015-08-06,"Helimagnetic thin films: surface reconstruction, surface spin-waves and magnetization","Quantum properties of a helimagnetic thin film of simple cubic lattice with
Heisenberg spin model are studied using the Green's function method. We find
that the spin configuration across the film is strongly non uniform. Using the
exactly determined spin configuration we calculate the spin-wave spectrum and
the layer magnetizations as functions of temperature T. We show the existence
of surface-localized modes which strongly affect the surface magnetization. We
also show that quantum fluctuations cause interesting spin contractions at T =
0 and give rise to a cross-over between layer magnetizations at low T .",1508.01367v1
2015-11-10,Charge and spin density in the helical Luttinger liquid,"The weakly interacting helical Luttinger liquid, due to spin momentum
locking, is characterized by extremely peculiar local observables: we show that
the density-density correlation functions do not exhibit signatures of Friedel
and Wigner oscillations, and that spin-spin correlation functions, which are
strongly anisotropic, witness the formation of a planar spin wave. Moreover, we
demonstrate that the most relevant scattering potentials involving a localized
impurity are not able to modify the electron density, while only magnetic
impurities can pin the planar spin density wave.",1511.03157v1
2016-07-12,Thermal spin dynamics of yttrium iron garnet,"Yttrium Iron Garnet is the prototypical material used to study pure spin
currents. It is a complex material with 20 magnetic atoms in the unit cell.
Almost all theories and experimental analysis approximates this complicated
material to a simple ferromagnet with a single spin wave mode. We use the
method of atomistic spin dynamics to study the temperature evolution of the
full 20 mode exchange spin wave spectrum. Our results show a strong frequency
dependence of the modes in quantitative agreement with neutron scattering
experiments. We find this causes in a reduction in the net spin pumping due to
the thermal occupation of optical modes with the opposite chirality to the FMR
mode.",1607.03263v1
2017-06-15,Misaligned Spin Merging Black Holes in Modified Gravity (MOG),"A promising signature of coalescing black holes is their spin angular
distribution. We consider the aLIGO collaboration gravitational wave
measurements of the binary black hole spins and the predicted modified gravity
(MOG) preference for misaligned spins of the coalescing black holes. In MOG,
during the merger of two black holes, the enhanced strength of gravitation
reduces the effective spin parameter $\chi_{\rm eff}\sim 0$ in agreement with
the measured spin misalignment of the merging black holes observed in the
gravitational wave detections by the aLIGO collaboration.",1706.05035v1
2018-04-10,Conversion of Heat into Charge Current by the Spin Wave Anomalous Nernst Effect,"A novel process of spin conversion from a temperature gradient to a
transverse voltage is addressed in this paper, viz. the anomalous Nernst effect
(ANE) in a ferromagnetic metal. We report that an additional voltage is
superposed on the conventional anomalous Nernst voltage in FePt crystalline
thin films. The dynamics of the local magnetization is modulated by the heat
current and excites spin waves. These generate a conduction electron spin
current via s-d coupling, which flows along the temperature gradient, and the
spin current is converted to a Nernst voltage by the inverse spin Hall effect.",1804.03751v1
2008-06-24,Signal propagation in time-dependent spin transport,"This paper analyzes theoretically the signal propagation in spin transport by
modulating the current passing through magnetic multilayers. Using a
macroscopic description of spin transport based on the dynamical Boltzmann
equation, we show that time-dependent spin transport possesses a wave-like
character that leads to modifications of pure spin-diffusion dynamics. In
particular, the wave-like characteristics allow one to extract a finite spin
signal-propagation velocity.",0806.3843v3
2022-12-11,Spin Excitation in Coupled Honeycomb Lattice Ni$_2$InSbO$_6$,"We performed an inelastic neutron scattering experiment on a polycrystalline
sample of a helimagnet Ni$_2$InSbO$_6$ to construct the spin Hamiltonian.
Well-defined spin-wave excitation with a band energy of 20 meV was observed
below $T_{N} = 76$ K. Using the linear spin-wave theory, the spectrum was
reasonably reproduced with honeycomb spin layers coupled along the stacking
axis (the $c$ axis). The proposed spin model reproduces the soliton lattice
induced by a magnetic field applied perpendicular to the $c$ axis.",2212.05413v1
2023-10-26,Gravitational Spin Hall Effect of Dirac Particle and the Weak Equivalence Principle,"We present a spin-induced none-geodesic effect of Dirac wave packets in a
static uniform gravitational field. Our approach is based on the
Foldy-Wouthuysen transformation of Dirac equation in a curved spacetime, which
predicts the gravitational spin-orbit coupling. Due to this coupling, we find
that the dynamics of the free-fall Dirac wave packets with opposite spin
polarization will yield the transverse splitting in the direction perpendicular
to spin orientation and gravity, which is known as the gravitational spin Hall
effect. Even in a static uniform gravitational field, such effect suggests that
the weak equivalence principle is violated for quantum particles.",2310.17581v1
2023-12-30,Ultrafast X-ray Diffraction Probe of Coherent Spin-state Dynamics in Molecules,"We propose an approach to probe coherent spin-state dynamics of molecules
using circularly polarized hard x-ray pulses. For the dynamically aligned
nitric oxide molecules in a coherent superposition spin-orbit coupled
electronic state that can be prepared through stimulated Raman scattering, we
demonstrate the capability of ultrafast x-ray diffraction to not only reveal
the quantum beating of the coherent spin-state wave packet, but also image the
spatial spin density of the molecule. With circularly polarized ultrafast x-ray
diffraction signal, we show that the electronic density matrix can be
retrieved. The spatio-temporal resolving power of ultrafast x-ray diffraction
paves the way for tracking transient spatial wave function in molecular
dynamics involving spin degree of freedom.",2401.00259v1
2008-10-28,Three-wave interactions of dispersive plasma waves propagating parallel to the magnetic field,"Three-wave interactions of plasma waves propagating parallel to the mean
magnetic field at frequencies below the electron cyclotron frequency are
considered. We consider Alfv\'en--ion-cyclotron waves,
fast-magnetosonic--whistler waves, and ion-sound waves. Especially the weakly
turbulent low-beta plasmas like the solar corona are studied, using the
cold-plasma dispersion relation for the transverse waves and the
fluid-description of the warm plasma for the longitudinal waves. We analyse the
resonance conditions for the wave frequencies $\omega$ and wavenumbers $k$, and
the interaction rates of the waves for all possible combinations of the three
wave modes, and list those reactions that are not forbidden.",0810.5059v2
2020-07-06,Searching for missing D'Alembert waves in nonlinear system: Nizhnik-Novikov-Veselov equation,"In linear science, the wave motion equation with general D'Alembert wave
solutions is one of the fundamental models. The D'Alembert wave is an arbitrary
travelling wave moving along one direction under a fixed model (material)
dependent velocity. However, the D'Alembert waves are missed when nonlinear
effects are introduced to wave motions. In this paper, we study the possible
travelling wave solutions, multiple soliton solutions and soliton molecules for
a special (2+1)-dimensional Koteweg-de Vries (KdV) equation, the so-called
Nizhnik-Novikov-Veselov (NNV) equation. The missed D'Alembert wave is
re-discovered from the NNV equation. By using the velocity resonance mechanism,
the soliton molecules are found to be closely related to D'Alembert waves. In
fact, the soliton molecules of the NNV equation can be viewed as special
D'Alembert waves. The interaction solutions among special D'Alembert type waves
($n$-soliton molecules and soliton-solitoff molecules) and solitons are also
discussed.",2007.02903v1
2022-04-09,Maxwell Matter Waves,"Maxwell matter waves emerge from a perspective, complementary to de
Broglie's, that matter is fundamentally a wave phenomenon whose particle
aspects are revealed by quantum mechanics. Their quantum mechanical description
is derived through the introduction of a matter vector potential, having
frequency $\omega_0$, to Schrodinger's equation for a massive particle. Maxwell
matter waves are then seen to be coherent excitations of a single-mode of the
matter-wave field. In the classical regime, their mechanics is captured by a
matter analog of Maxwell's equations for the electromagnetic field. As such,
Maxwell matter waves enable a spectrum of systems that have useful optical
analogs, such as resonant matter-wave interferometric sensors and matter-wave
parametric oscillators. These waves are associated with a wavelength that is
tied to the drive frequency $\omega_0$ rather than to the massive particle's
energy, as is ordinarily the case with de Broglie matter waves. As a result,
simple interferometric measurements lead to different outcomes for the two
types of waves. While their apparent departure from de Broglie character is
surprising, Maxwell matter waves are wholly consistent with quantum mechanics.",2204.04549v1
2011-06-02,Kinetics of Spin Relaxation in Wires and Channels: Boundary Spin Echo and Tachyons,"In this paper we use a spin kinetic equation to study spin polarization
dynamics in 1D wires and 2D channels. This approach is valid in both diffusive
and ballistic spin transport regimes and, therefore, more general than the
usual spin drift-diffusion equations. In particular, we demonstrate that in
infinite 1D wires with Rashba spin-orbit interaction the exponential spin
relaxation decay can be modulated by an oscillating function. In the case of
spin relaxation in finite length 1D wires, it is shown that an initially
homogeneous spin polarization spontaneously transforms into a persistent spin
helix. An interesting sound waves echo-like behavior of initially localized
spin polarization packet is found in finite length wires. We show that a
propagating spin polarization profile reflects from a system boundary and
returns back to its initial position similarly to the reflectance of sound
waves from an obstacle. Green's function of spin kinetic equation is found for
both finite and infinite 1D systems. Moreover, we demonstrate explicitly that
the spin relaxation in 2D channels with Rashba and Dresselhaus spin-orbit
interactions of equal strength occurs similarly to that in 1D wires of finite
length. Finally, a simple transformation mapping 1D spin kinetic equation into
the Klein-Gordon equation with an imaginary mass is found thus establishing an
interesting connection between semiconductor spintronics and relativistic
quantum mechanics.",1106.0355v1
2015-11-04,"Compositeness of baryonic resonances: Applications to the Delta(1232), N(1535), and N(1650) resonances","We present a formulation of the compositeness for baryonic resonances in
order to discuss the meson-baryon molecular structure inside the resonances.
For this purpose, we derive a relation between the residue of the scattering
amplitude at the resonance pole position and the two-body wave function of the
resonance in a sophisticated way, and we define the compositeness as the norm
of the two-body wave functions. As applications, we investigate the
compositeness of the $\Delta (1232)$, $N (1535)$, and $N (1650)$ resonances
from precise $\pi N$ scattering amplitudes in a unitarized chiral framework
with the interaction up to the next-to-leading order in chiral perturbation
theory. The $\pi N$ compositeness for the $\Delta (1232)$ resonance is
evaluated in the $\pi N$ single-channel scattering, and we find that the $\pi
N$ component inside $\Delta (1232)$ in the present framework is nonnegligible,
which supports the previous work. On the other hand, the compositeness for the
$N (1535)$ and $N (1650)$ resonances is evaluated in a coupled-channels
approach, resulting that the $\pi N$, $\eta N$, $K \Lambda$ and $K \Sigma$
components are negligible for these resonances.",1511.01200v2
2013-10-29,Self-Quenching of Nuclear Spin Dynamics in Central Spin Problem,"We consider, in the framework of the central spin $s=1/2$ model, driven
dynamics of two electrons in a double quantum dot subject to hyperfine
interaction with nuclear spins and spin-orbit coupling. The nuclear subsystem
dynamically evolves in response to Landau-Zener singlet-triplet transitions of
the electronic subsystem controlled by external gate voltages. Without noise
and spin-orbit coupling, subsequent Landau-Zener transitions die out after
about $10^4$ sweeps, the system self-quenches, and nuclear spins reach one of
the numerous glassy dark states. We present an analytical model that captures
this phenomenon. We also account for the multi-nuclear-specie content of the
dots and numerically determine the evolution of around $10^7$ nuclear spins in
up to $2\times10^5$ Landau-Zener transitions. Without spin-orbit coupling,
self-quenching is robust and sets in for arbitrary ratios of the nuclear spin
precession times and the waiting time between Landau-Zener sweeps as well as
under moderate noise. In presence of spin-orbit coupling of a moderate
magnitude, and when the waiting time is in resonance with the precession time
of one of the nuclear species, the dynamical evolution of nuclear polarization
results in stroboscopic screening of spin-orbit coupling. However, small
deviations from the resonance or strong spin-orbit coupling destroy this
screening. We suggest that the success of the feedback loop technique for
building nuclear gradients is based on the effect of spin-orbit coupling.",1310.7847v1
2016-11-17,Inductive detection of field-like and damping-like AC inverse spin-orbit torques in ferromagnet/normal metal bilayers,"Functional spintronic devices rely on spin-charge interconversion effects,
such as the reciprocal processes of electric field-driven spin torque and
magnetization dynamics-driven spin and charge flow. Both damping-like and
field-like spin-orbit torques have been observed in the forward process of
current-driven spin torque and damping-like inverse spin-orbit torque has been
well-studied via spin pumping into heavy metal layers. Here we demonstrate that
established microwave transmission spectroscopy of ferromagnet/normal metal
bilayers under ferromagnetic resonance can be used to inductively detect the AC
charge currents driven by the inverse spin-charge conversion processes. This
technique relies on vector network analyzer ferromagnetic resonance (VNA-FMR)
measurements. We show that in addition to the commonly-extracted spectroscopic
information, VNA-FMR measurements can be used to quantify the magnitude and
phase of all AC charge currents in the sample, including those due to spin
pumping and spin-charge conversion. Our findings reveal that
Ni$_{80}$Fe$_{20}$/Pt bilayers exhibit both damping-like and field-like inverse
spin-orbit torques. While the magnitudes of both the damping-like and
field-like inverse spin-orbit torque are of comparable scale to prior reported
values for similar material systems, we observed a significant dependence of
the damping-like magnitude on the order of deposition. This suggests interface
quality plays an important role in the overall strength of the damping-like
spin-to-charge conversion.",1611.05798v2
1999-04-20,The dimer-RVB State of the Four-Leg Heisenberg Ladder: Interference among Resonances,"We study the ground state of the 4-leg spin ladder using a dimer-RVB ansatz
and the Lanczos method. Besides the well known resonance mechanism between
valence bond configurations we find novel interference effects among nearby
resonances.",9904286v1
1999-09-08,Non-Resonant Effects in Implementation of Quantum Shor Algorithm,"We simulate Shor's algorithm on an Ising spin quantum computer. The influence
of non-resonant effects is analyzed in detail. It is shown that our ``$2\pi
k$''-method successfully suppresses non-resonant effects even for relatively
large values of the Rabi frequency.",9909027v2
2014-12-15,Charmed baryonic resonances in medium,"We discuss the behavior of dynamically-generated charmed baryonic resonances
in matter within a unitarized coupled-channel model consistent with heavy-quark
spin symmetry. We analyze the implications for the formation of $D$-meson bound
states in nuclei and the propagation of $D$ mesons in heavy-ion collisions from
RHIC to FAIR energies.",1412.4811v1
1992-05-29,Resonant Spin-Flavor Precession of Neutrinos As a Possible Solution to the Solar Neutrino Problem,"Recent developments of the resonant neutrino spin-flavor precession scenario
and its applications to the solar neutrino problem are reviewed. We discuss in
particular the possibilities of reconciliation of strong time variations of the
solar neutrino flux observed in the Homestake ${}^{37}\$Cl experiment with
little or no time variation seen in the Kamiokande II experiment.",9205244v1
2009-09-13,Refocussing off-resonant spin-1/2 evolution using spinor behavior,"A systematic method is presented for constructing increasingly precise
sequences to refocus off-resonant spin evolution with severely limited control
amplitude. Sequences obtained should be readily applicable to the case of
electron spin qubits in quantum dots with random nuclear fields, and other
qubit systems with systematic qubit splitting errors comparable to control
field amplitude.",0909.2449v1
2020-09-15,Nucleon resonances with higher spins in soft-wall AdS/QCD,"We present a study of electroexcitation of nucleon resonances with higher
spins, in a soft-wall AdS/QCD model, comparing our results with existing data
from the CLAS Collaboration at JLab, from MAMI, and other experiments.",2009.07115v1
2021-06-18,An Automated Global Method for Extraction of Distance Distributions from Electron Spin Resonance Pulsed Dipolar Signals,"Electron spin resonance (ESR) pulsed dipolar spectroscopy (PDS) is used
effectively in measuring nano-meter range distances for protein structure
prediction. The current global approach in extracting the distance distribution
from time domain PDS signal has multiple limitations. We present a parameter
free global method, which is more efficacious and less sensitive to signal
noise compared to the current method.",2106.10306v1
2021-06-29,Optimal Background Correction in Double Quantum Coherence Electron Spin Resonance Spectroscopy for Accurate Data Analysis,"Electron spin resonance (ESR) pulsed dipolar spectroscopy (PDS) is used in
protein 3D structure determination. However, the accuracy of the signal
analysis depends heavily on the background correction process. In this work, we
derive the functional forms of double quantum coherence (DQC) ESR signal in
typical frozen samples of micro-molar concentration, quantifying both the
intramolecular and the background contributions.",2106.15733v1
2015-06-16,Evidence of quantum dimer excitations in Sr$_3$Ir$_2$O$_7$,"The magnetic excitation spectrum in the bilayer iridate Sr$_3$Ir$_2$O$_7$ has
been investigated using high-resolution resonant inelastic x-ray scattering
(RIXS) performed at the iridium L$_3$ edge and theoretical techniques. A study
of the systematic dependence of the RIXS spectrum on the orientation of the
wavevector transfer, $\mathbf{Q}$, with respect to the iridium-oxide bilayer
has revealed that the magnon dispersion is comprised of two branches well
separated in energy and gapped across the entire Brillouin zone. Our results
contrast with those of an earlier study which reported the existence of a
single dominant branch. While these earlier results were interpreted as two
overlapping modes within a spin-wave model of weakly coupled iridium-oxide
planes, our results are more reminiscent of those expected for a system of
weakly coupled dimers. In this latter approach the lower and higher energy
modes find a natural explanation as those corresponding to transverse and
longitudinal fluctuations, respectively. We have therefore developed a
bond-operator theory which describes the magnetic dispersion in
Sr$_3$Ir$_2$O$_7$ in terms of quantum dimer excitations. In our model
dimerisation is produced by the leading Heisenberg exchange, $J_c$, which
couples iridium ions in adjacent planes of the bilayer. The Hamiltonian also
includes in plane exchange, $J$, as well as further neighbour couplings and
relevant anisotropies. The bond-operator theory provides an excellent account
of the dispersion of both modes, while the measured $\mathbf{Q}$ dependence of
the RIXS intensities is in reasonable qualitative accord with the spin-spin
correlation function calculated from the theory. We discuss our results in the
context of the quantum criticality of bilayer dimer systems in the presence of
anisotropic interactions derived from strong spin-orbit coupling.",1506.04877v1
2016-02-04,Magnetic anisotropy in the frustrated spin chain compound $β$-TeVO$_4$,"Isotropic and anisotropic magnetic behavior of the frustrated spin chain
compound $\beta$-TeVO$_4$ is reported. Three magnetic transitions observed in
zero magnetic field are tracked in fields applied along different
crystallographic directions using magnetization, heat capacity, and
magnetostriction measurements. Qualitatively different temperature-field
diagrams are obtained below 10 T for the field applied along $a$ or $b$ and
along $c$, respectively. In contrast, a nearly isotropic high-field phase
emerges above 18 T and persists up to the saturation that occurs around 22.5 T.
Upon cooling in low fields, the transitions at $T_{\rm N1}$ and $T_{\rm N2}$
toward the spin-density-wave and stripe phases are of the second order, whereas
the transition at $T_{\rm N3}$ toward the helical state is of the first order
and entails a lattice component. Our microscopic analysis identifies frustrated
$J_1-J_2$ spin chains with a sizable antiferromagnetic interchain coupling in
the $bc$ plane and ferromagnetic couplings along the $a$ direction. The
competition between these ferromagnetic interchain couplings and the helical
order within the chain underlies the incommensurate order along the
$a$-direction, as observed experimentally. Although a helical state is
triggered by the competition between $J_1$ and $J_2$ within the chain, the
plane of the helix is not uniquely defined because of competing magnetic
anisotropies. Using high-resolution synchrotron diffraction and $^{125}$Te
nuclear magnetic resonance, we also demonstrate that the crystal structure of
$\beta$-TeVO$_4$ does not change down to 10 K, and the orbital state of
V$^{4+}$ is preserved.",1602.01632v2
2020-11-03,Multigaps superconductivity at unconventional Lifshitz transition in a 3D Rashba heterostructure at atomic limit,"It is well known that the critical temperature of multi-gap superconducting
3D heterostructures at atomic limit (HAL) made of a superlattice of atomic
layers with an electron spectrum made of several quantum subbands can be
amplified by a shape resonance driven by the contact exchange interaction
between different gaps. The $T_C$ amplification is achieved tuning the Fermi
level near the singular nodal point at a Lifshitz transition for opening a
neck. Recently high interest has been addressed to the breaking of inversion
symmetry which leads to a linear-in-momentum spin-orbit induced spin splitting,
universally referred to as Rashba spin-orbit coupling (RSOC) also in 3D layered
metals. However the physics of multi-gap superconductivity near unconventional
Lifshitz transitions in 3D HAL with RSOC, being in a non-BCS regime, is not
known. The key result of this work getting the superconducting gaps by
Bogoliubov theory and the 3D electron wave functions by solution of the Dirac
equation is the feasibility of tuning multi-gap superconductivity by suitably
matching the spin-orbit length with the 3D superlattice period. It is found
that the presence of the RSOC amplifies both the k dependent anisotropic gap
function and the critical temperature when the Fermi energy is tuned near the
circular nodal line. Our results suggest a method to effectively vary the
effect of RSOC on macroscopic superconductor condensates via the tuning of the
superlattice modulation parameter in a way potentially relevant for spintronics
functionalities in several existing experimental platforms and tunable
materials needed for quantum devices for quantum computing.",2011.02311v2
2023-06-16,Bose-Einstein condensation of a two-magnon bound state in a spin-one triangular lattice,"Interactions of collective excitations often lead to rich emergent phenomena
in many-particle quantum systems. In ordered magnets, the elementary
excitations are spin waves (magnons), which obey Bose-Einstein statistics.
Similar to the Cooper pairs in superconductors, magnons can be paired into
bound states under attractive interactions. Even more interestingly, the Zeeman
coupling to a magnetic field acts as a chemical potential that can tune the
particle density through a quantum critical point (QCP), beyond which a
``hidden order'' is predicted to exist. However, experimental confirmation of
this QCP and the associated new state of matter remain elusive. Here we report
direct observation of the Bose-Einstein condensation (BEC) of the two-magnon
bound state in Na$_2$BaNi(PO$_4$)$_2$. Comprehensive thermodynamic measurements
confirmed the existence of a two-dimensional BEC-QCP at the saturation field.
Inelastic neutron scattering experiments were performed to accurately establish
the magnetic exchange model. An exact solution of the model found stable
2-magnon bound states that were further confirmed by an electron spin resonance
(ESR) experiment, demonstrating that the QCP is due to the pair condensation
and the phase below saturation field is the long-sought-after spin nematic (SN)
phase.",2306.09695v1
1998-05-19,The effect of an isothermal atmosphere on the propagation of three-dimensional waves in a thermally stratified accretion disk,"We extend our analysis of the three-dimensional response of a vertically
polytropic disk to tidal forcing at Lindblad resonances by including the
effects of a disk atmosphere. The atmosphere is modeled as an isothermal layer
that joins smoothly on to an underlying polytropic layer. The launched wave
progressively enters the atmosphere as it propagates away from the resonance.
The wave never propagates vertically, however, and the wave energy rises to a
(finite) characteristic height in the atmosphere. The increase of wave
amplitude associated with this process of wave channeling is reduced by the
effect of the atmosphere. For waves of large azimuthal mode number m generated
by giant planets embedded in a disk, the increase in wave amplitude is still
substantial enough to be likely to dissipate the wave energy by shocks for even
modest optical depths (tau greater than about 10) over a radial distance of a
few times the disk thickness. For low-m waves generated in circumstellar disks
in binary stars, the effects of wave channeling are less important and the
level of wave nonlinearity increases by less than a factor of 10 in going from
the disk edge to the disk center. For circumbinary disks, the effects of wave
channeling remain important, even for modest values of optical depth.",9805254v1
2019-06-19,Bimodal directional propagation of wind-generated ocean surface waves,"Over the years, the directional distribution functions of wind-generated wave
field have been assumed to be unimodal. While details of various functional
forms differ, these directional models suggest that waves of all spectral
components propagate primarily in the wind direction. The beamwidth of the
directional distribution is narrowest near the spectral peak frequency, and
increases toward both higher and lower frequencies. Recent advances in global
positioning, laser ranging and computer technologies have made it possible to
acquire high-resolution 3D topography of ocean surface waves. Directional
spectral analysis of the ocean surface topography clearly shows that in a young
wave field, two dominant wave systems travel at oblique angles to the wind and
the ocean surface display a crosshatched pattern. One possible mechanism
generating this bimodal directional wave field is resonant propagation as
suggested by Phillips resonance theory of wind wave generation. For a more
mature wave field, wave components shorter than the peak wavelength also show
bimodal directional distributions symmetric to the dominant wave direction. The
latter bimodal directionality is produced by Hasselmann nonlinear wave-wave
interaction mechanism. The implications of these directional observations on
remote sensing (directional characteristics of ocean surface roughness) and
air-sea interaction studies (directional properties of mass, momentum and
energy transfers) are significant.",1906.07984v1
2016-11-01,Particle Scattering off of Right-Handed Dispersive Waves,"Resonant scattering of fast particles off low frequency plasma waves is a
major process determining transport characteristics of energetic particles in
the heliosphere and contributing to their acceleration. Usually, only Alfv\'en
waves are considered for this process, although dispersive waves are also
present throughout the heliosphere. We investigate resonant interaction of
energetic electrons with dispersive, right-handed waves. For the interaction of
particles and a single wave a variable transformation into the rest frame of
the wave can be performed. Here, wellestablished analytic models derived in the
framework of magnetostatic quasi-linear theory (QLT) can be used as a reference
to validate simulation results. However, this approach fails as soon as several
dispersive waves are involved. Based on analytic solutions modeling the
scattering amplitude in the magnetostatic limit, we present an approach to
modify these equations for the use in the plasma frame. Thereby we aim at a
description of particle scattering in the presence of several waves. A
Particle-in-Cell (PiC) code is employed to study wave-particle scattering on a
micro-physically correct level and to test the modified model equations. We
investigate the interactions of electrons at different energies (from 1 keV to
1 MeV) and right-handed waves with various amplitudes. Differences between
model and simulation arise in the case of high amplitudes or several waves.
Analyzing the trajectories of single particles we find no microscopic diffusion
in the case of a single plasma wave, although a broadening of the particle
distribution can be observed.",1611.00310v1
2000-09-15,Gravitational waves from a spinning particle scattered by a relativistic star: Axial mode case,"We study gravitational waves from a spinning test particle scattered by a
relativistic star using a perturbation method. The present analysis is
restricted to axial modes. By calculating the energy spectrum, the waveforms
and the total energy and angular momentum of gravitational waves, we analyze
the dependence of the emitted gravitational waves on a particle spin. For a
normal neutron star, the energy spectrum has one broad peak whose
characteristic frequency corresponds to the angular velocity at the turning
point (a periastron). Since the turning point is determined by the orbital
parameter, there exists the dependence of the gravitational wave on a particle
spin. We find that the total energy of $l = 2$ gravitational waves gets larger
as the spin increases in the anti-parallel direction to the orbital angular
momentum. For an ultracompact star, in addition to such an orbital
contribution, we find the quasi-normal modes exited by a scattered particle,
whose excitation rate to gravitational waves depends on the particle spin. We
also discuss the ratio of the total angular momentum to the total energy of
gravitational waves and explain its spin dependence.",0009055v1
2014-11-12,Magnonic Holographic Memory: from Proposal to Device,"In this work, we present recent developments in magnonic holographic memory
devices exploiting spin waves for information transfer. The devices comprise a
magnetic matrix and spin wave generating/detecting elements placed on the edges
of the waveguides. The matrix consists of a grid of magnetic waveguides
connected via cross junctions. Magnetic memory elements are incorporated within
the junction while the read-in and read-out is accomplished by the spin waves
propagating through the waveguides. We present experimental data on spin wave
propagation through NiFe and YIG magnetic crosses. The obtained experimental
data show prominent spin wave signal modulation (up to 20 dB for NiFe and 35 dB
for YIG) by the external magnetic field, where both the strength and the
direction of the magnetic field define the transport between the cross arms. We
also present experimental data on the 2-bit magnonic holographic memory built
on the double cross YIG structure with micro-magnets placed on the top of each
cross. It appears possible to recognize the state of each magnet via the
interference pattern produced by the spin waves with all experiments done at
room temperature. Magnonic holographic devices aim to combine the advantages of
magnetic data storage with wave-based information transfer. We present
estimates on the spin wave holographic devices performance, including power
consumption and functional throughput. According to the estimates, magnonic
holographic devices may provide data processing rates higher than 10^18
bits/cm2/s while consuming 0.15uW. Technological challenges and fundamental
physical limits of this approach are also discussed.",1411.3388v1
2021-04-30,A numerical exploration of signal detector arrangement in a spin-wave reservoir computing device,"This paper studies numerically how the signal detector arrangement influences
the performance of reservoir computing using spin waves excited in a
ferrimagnetic garnet film. This investigation is essentially important since
the input information is not only conveyed but also transformed by the spin
waves into high-dimensional information space when the waves propagate in the
film in a spatially distributed manner. This spatiotemporal dynamics realizes a
rich reservoir-computational functionality. First, we simulate spin waves in a
rectangular garnet film with two input electrodes to obtain spatial
distributions of the reservoir states in response to input signals, which are
represented as spin vectors and used for a machine-learning waveform
classification task. The detected reservoir states are combined through readout
connection weights to generate a final output. We visualize the spatial
distribution of the weights after training to discuss the number and positions
of the output electrodes by arranging them at grid points, equiangularly
circular points or at random. We evaluate the classification accuracy by
changing the number of the output electrodes, and find that a high accuracy
($>$ 90\%) is achieved with only several tens of output electrodes regardless
of grid, circular or random arrangement. These results suggest that the spin
waves possess sufficiently complex and rich dynamics for this type of tasks.
Then we investigate in which area useful information is distributed more by
arranging the electrodes locally on the chip. Finally, we show that this device
has generalization ability for input wave-signal frequency in a certain
frequency range. These results will lead to practical design of spin-wave
reservoir devices for low-power intelligent computing in the near future.",2104.14915v1
2019-01-24,Fundamentals of magnon-based computing,"A disturbance in the local magnetic order of a solid body can propagate
across a material just like a wave. This wave is named spin wave, and its
quanta are known as magnons. Recently, physicists proposed the usage of magnons
to carry and process information instead of electrons as it is the case of
electronics. This technology opens access to a new generation of computers in
which data are processed without motion of any real particles like electrons.
This leads to a sizable decrease in the accompanying heating losses and,
consequently, to lower energy consumption, which is crucial due to the ever
increasing demand for computing devices. Moreover, unique properties of spin
waves allow for the utilisation of unconventional computing concepts, giving
the vision of a significantly faster and more powerful next-generation of
information processing systems.
  The current review addresses a selection of fundamental topics that form the
basis of the magnon-based computing and are of primary importance for the
further development of this concept. First, the transport of spin-wave-carried
information in one and two dimensions that is required for the realization of
logic elements and integrated magnon circuits is covered. Second, the
convertors between spin waves and electron (charge and spin) currents are
discussed. These convertors are necessary for the compatibility of magnonic
devices with modern CMOS technology. The paper starts with basics on spin waves
and the related methodology. In addition, the general ideas behind magnon-based
computing are presented. The review finishes with conclusions and an outlook on
the perspective use of spin waves.",1901.08934v1
2019-08-07,Reconfigurable sub-micron spin-wave majority gate with electrical transducers,"Spin waves are excitations in ferromagnetic media that have been proposed as
information carriers in hybrid spintronic devices with much lower operation
power than conventional charge-based electronics. Their wave nature can be
exploited in majority gates by using interference for computation. However, a
scalable spin-wave majority gate that can be co-integrated alongside
conventional electronics is still lacking. Here, we demonstrate a sub-micron
inline spin-wave majority gate with fan-out. Time-resolved imaging of the
magnetization dynamics by scanning transmission x-ray microscopy illustrates
the device operation. All-electrical spin-wave spectroscopy further
demonstrates majority gates with sub-micron dimensions, reconfigurable input
and output ports, and frequency-division multiplexing. Challenges for hybrid
spintronic computing systems based on spin-wave majority gates are discussed.",1908.02546v3
2019-09-10,"Twisting and tweezing the spin wave: on vortices, skyrmions, helical waves, and the magnonic spiral phase plate","Spin waves are the low-energy excitations of magnetically ordered materials.
They are key elements in the stability analysis of the ordered phase and have a
wealth of technological applications. Recently, we showed that spin waves of a
magnetic nanowire may carry a definite amount of orbital angular momentum
components along the propagation direction. This helical, in addition to the
chiral, character of the spin waves is related to the spatial modulations of
the spin wave phase across the wire. It, however, remains a challenge to
generate and control such modes with conventional magnetic fields. Here, we
make the first proposal for a \textit{magnetic} spiral phase plate by
appropriately synthesizing two magnetic materials that have different speeds of
spin waves. It is demonstrated with full-numerical micromagnetic simulations
that despite the complicated structure of demagnetization fields, a homogeneous
spin wave passing through the spiral phase plate attains the required twist and
propagates further with the desired orbital angular momentum. While excitations
from the ordered phase may have a twist, the magnetization itself can be
twisted due to internal fields and forms what is known as a magnetic vortex. We
point out the differences between both types of magnetic phenomena and discuss
their possible interaction.",1909.04457v2
2021-11-30,Comparison of spin-wave transmission in parallel and antiparallel magnetic configurations,"Parallel (P) and antiparallel (AP) configurations are widely applied in
magnetic heterostructures and have significant impacts on the spin-wave
transmission in magnonic devices. In the present study, a theoretical
investigation was conducted into the transmission of exchange-dominated spin
waves with nanoscale wavelengths in a type of heterostructure including two
magnetic media, of which the magnetization state can be set to the P (AP)
configuration by ferromagnetic (antiferromagnetic) interfacial exchange
coupling (IEC). The boundary conditions in P and AP cases were derived, by
which the transmission and reflection coefficients of spin waves were
analytically given and numerically calculated. In the P configuration, a
critical angle $\theta_{\textrm{c}}$ always exists and has a significant
influence on the transmission. Spin waves are refracted and reflected when the
incident angle $\theta_{\textrm{i}}$ is smaller than the critical angle
($\theta_{\textrm{i}} < \theta_{\textrm{c}}$), while total reflection occurs as
$\theta_{\textrm{i}} \geq \theta_{\textrm{c}}$. In the AP configuration, the
spin-wave polarizations of medium 1 and 2 are inverse, that is, right-handed
(RH) and left-handed (LH), leading to the total reflection being independent of
$\theta_{\textrm{i}}$. As demonstrated by the difference in spin-wave
transmission properties between the P ($\theta_{\textrm{i}} <
\theta_{\textrm{c}}$) and AP cases, there is a polarization-dependent
scattering. However, as $\theta_{\textrm{i}}$ exceeds $\theta_{\textrm{c}}$,
the P ($\theta_{\textrm{i}} > \theta_{\textrm{c}}$) case exhibits similarities
with the AP case, where the transmitted waves are found to be evanescent in
medium 2 and their decay lengths are investigated.",2111.15091v2
2011-03-11,Spin-orbital resonating valence bond liquid on a triangular lattice: Evidence from finite-cluster diagonalization,"We investigate the ground state of the $d^1$ spin-orbital model for triply
degenerate $t_{2g}$ orbitals on a triangular lattice which unifies intrinsic
frustration of spin and orbital interactions with geometrical frustration.
Using full or Lanczos exact diagonalization of finite clusters we establish
that the ground state of the spin-orbital model which interpolates between the
superexchange and direct exchange interactions on the bonds is characterized by
valence-bond correlations. In the absence of Hund's exchange the model
describes a competition between various possible valence-bond states. By
considering the clusters with open boundary conditions we demonstrate that
orbital interactions are always frustrated, but this frustration is removed by
pronounced spin singlet correlations which coexist with supporting them dimer
orbital correlations. Such local configurations contribute to the disordered
ground states found for the clusters with periodic boundary conditions which
interpolate between a highly resonating, dimer-based, entangled spin-orbital
liquid phase, and a valence-bond state with completely static spin-singlet
states. We argue that these states are also realized for the infinite lattice
and anticipate that pronounced transitions between different regimes found for
particular geometries will turn out to smooth crossovers in the properties of
the spin-orbital liquid in the thermodynamic limit. Finally, we provide
evidence that the resonating spin-orbital liquid phase involves entangled
states on the bonds. In such a phase classical considerations based on the
mean-field theory cannot be used, spin exchange interactions do not determine
spin bond correlations, and quantum fluctuations play a crucial role in the
ground states and magnetic transitions.",1103.2319v1
2017-01-23,Electrically driving nuclear spin qubits with microwave photonic bangap resonators,"The electronic and nuclear spin degrees of freedom for donor impurities in
semiconductors form ultra coherent two-level systems that are useful for
quantum information applications. Spins naturally have magnetic dipoles, so
alternating current (AC) magnetic fields are frequently used to drive spin
transitions and perform quantum gates. These fields can be difficult to
spatially confine to single donor qubits so alternative methods of control such
as AC electric field driven spin resonance are desirable. However, donor spin
qubits do not have electric dipole moments so that they can not normally be
driven by electric fields. In this work we challenge that notion by
demonstrating a new, all-electric-field method for controlling neutral $^{31}$P
and $^{75}$As donor nuclear spins in silicon through modulation of their
donor-bound electrons. This method has major advantages over magnetic field
control since electric fields are easy to confine at the nanoscale. This leads
to lower power requirements, higher qubit densities, and faster gate times. We
also show that this form of control allows for driving nuclear spin qubits at
either their resonance frequency or the first subharmonic of that frequency,
thus reducing device bandwidth requirements. Interestingly, as we relax the
bandwidth requirements, we demonstrate that the computational Hilbert space is
expanded to include double quantum transitions, making it feasible to use all
four nuclear spin states to implement nuclear-spin-based qudits in Si:As. Based
on these results, one can envision novel high-density, low-power quantum
computing architectures using nuclear spins in silicon.",1701.06650v1
2016-07-04,The ubiquitous photonic wheel,"A circularly polarized electromagnetic plane wave carries an electric field
that rotates clockwise or counterclockwise around the propagation direction of
the wave. According to the handedness of this rotation, its \emph{longitudinal}
spin angular momentum density is either parallel or antiparallel to the
propagation of light. However, there are also light waves that are not simply
plane and carry an electric field that rotates around an axis perpendicular to
the propagation direction, thus yielding \emph{transverse} spin angular
momentum density. Electric field configurations of this kind have been
suggestively dubbed ""photonic wheels"". It has been recently shown that photonic
wheels are commonplace in optics as they occur in electromagnetic fields
confined by waveguides, in strongly focused beams, in plasmonic and evanescent
waves. In this work we establish a general theory of electromagnetic waves
{propagating along a well defined direction, which carry} transverse spin
angular momentum density. We show that depending on the shape of {these waves,
the} spin density may be either perpendicular to the \emph{mean} linear
momentum (globally transverse spin) or to the linear momentum \emph{density}
(locally transverse spin). We find that the latter case generically occurs only
for non-diffracting beams, such as the Bessel beams. Moreover, we introduce the
concept of \emph{meridional} Stokes parameters to operationally quantify the
transverse spin density. To illustrate our theory, we apply it to the exemplary
cases of Bessel beams and evanescent waves. These results open a new and
accessible route to the understanding, generation and manipulation of optical
beams with transverse spin angular momentum density.",1607.00792v1
2018-07-02,Emission and Propagation of Multi-Dimensional Spin Waves with nanoscale wavelengths in Anisotropic Spin Textures,"Spin waves offer intriguing novel perspectives for computing and signal
processing, since their damping can be lower than the Ohmic losses in
conventional CMOS circuits. For controlling the spatial extent and propagation
of spin waves on the actual chip, magnetic domain walls show considerable
potential as magnonic waveguides. However, low-loss guidance of spin waves with
nanoscale wavelengths, in particular around angled tracks, remains to be shown.
Here we experimentally demonstrate that such advanced control of propagating
spin waves can be obtained using natural features of magnetic order in an
interlayer exchange-coupled, anisotropic ferromagnetic bilayer. Using Scanning
Transmission X-Ray Microscopy, we image generation of spin waves and their
propagation across distances exceeding multiple times the wavelength, in
extended planar geometries as well as along one-dimensional domain walls, which
can be straight and curved. The observed range of wavelengths is between 1
{\mu}m and 150 nm, at corresponding excitation frequencies from 250 MHz to 3
GHz. Our results show routes towards practical implementation of magnonic
waveguides employing domain walls in future spin wave logic and computational
circuits.",1807.00897v2
2017-06-19,Pinned domain wall oscillator as tunable direct current spin wave emitter,"Spin waves are perturbations in the relative orientation of magnetic moments
in a continuous magnetic system, which have been proposed as a new kind of
information carrier for spin-based low power applications. For this purpose, a
major obstacle to overcome is the energy-efficient excitation of coherent short
wavelength spin waves and alternatives to excitation via the Oersted field of
an alternating current need to be explored. Here we show, by means of
micromagnetic simulations, how, in a perpendicularly magnetized thin strip, a
domain wall pinned at a geometrical constriction emits spin waves when forced
to rotate by the application of a low direct current flowing along the strip.
Spin waves propagate only in the direction of the electron's flow at the first
odd harmonic of the domain wall rotation frequency for which propagation is
allowed. Excitation is due to in-plane dipolar stray field of the rotating
domain wall and that the resulting unidirectionality is a consequence of the
domain wall displacement at the constriction. On the other hand, the
application of an external field opposing domain wall depinning breaks the
symmetry for spin wave propagation in the two domains, allowing emission in
both directions but at different frequencies. The results presented define a
new approach to produce tunable high frequency spin wave emitters of easy
fabrication and low power consumption.",1706.05873v1
2024-02-24,Steerable current-driven emission of spin waves in magnetic vortex pairs,"The efficient excitation of spin waves is a key challenge in the realization
of magnonic devices. We demonstrate the current-driven generation of spin waves
in antiferromagnetically coupled magnetic vortices. We employ time-resolved
scanning transmission X-ray microscopy (TR-STXM) to directly image the emission
of spin waves upon the application of an alternating current flowing directly
through the magnetic stack. Micromagnetic simulations allow us to identify the
origin of the excitation to be the current-driven Oersted field, which in the
present system proves to be orders of magnitude more efficient than the
commonly used excitation via stripline antennas. Our numerical studies also
reveal that the spin-transfer torque can lead to the emission of spin waves as
well, yet only at much higher current amplitudes. By using magnetostrictive
materials, we futhermore demonstrate that the direction of the magnon
propagation can be steered by increasing the excitation amplitude, which
modifies the underlying magnetization profile through an additional anisotropy
in the magnetic layers. The demonstrated methods allow for the efficient and
tunable excitation of spin waves, marking a significant advance in the
generation and control of spin waves in magnonic devices.",2402.15831v1
2002-12-04,Spin-resolved off-specular neutron scattering from magnetic domain walls using the polarized $^3He$ gas spin filter,"We report on the use of the polarized $^3$He gas filter and neutron resonant
enhancement techniques for the measurement of spin-polarized diffuse neutron
scattering due to ferromagnetic domains. A CoO/Co exchange biased bilayer was
grown on a Ti/Cu/$Al_2O_3$ neutron resonator template. The system is cooled in
an applied magnetic field of $H_a=2000$ Oe through the N\'{e}el temperature of
the antiferromagnet to 10 K where the applied magnetic field is swept as to
measure the magnetic hysteresis loop. After the second magnetization reversal
at the coercive field $H_{c2}=+ 230$ Oe, the system is supposed to approach the
original magnetic configuration. In order to prove that this is not the case
for our exchange biased bilayer, we have measured four off-specular maps I++,
I+-, I-+, I-- at $H_a \approx + 370$ Oe, where the Co magnetic spins were
mostly reversed. They show a striking behavior in the total reflection region:
while the nonspin-flip scattering exhibits no diffuse reflectivity, the
spin-flip scattering shows strong diffuse scattering at incident angles which
satisfy the resonance conditions. Moreover the spin-flip off-specular part of
the reflectivity is asymmetric. The I-+ intensity occurs at higher exit angles
than the specularly reflected neutrons, and the I+- intensity is shifted to
lower angles. Their intensities are noticeably different and there is a
splitting of the resonance positions for the up and down neutron spins
($\alpha_{n} ^{+} \ne \alpha_{n} ^{-}$) . Additionally, a strong influence of
the stray fields from magnetic domains to the resonance splitting is observed.",0212092v1
2011-03-02,Effect of current hysteresis on the spin polarization of current in a paramagnetic resonant tunneling diode,"A spin-dependent quantum transport is investigated in a paramagnetic resonant
tunneling diode (RTD) based on a Zn$_{1-x}$Mn$_x$Se/ZnBeSe heterostructure.
Using the Wigner-Poisson method and assuming the two-current model we have
calculated the current-voltage characteristics, potential energy profiles and
electron density distributions for spin-up and spin-down electron current in an
external magnetic field. We have found that -- for both the spin-polarized
currents -- two types of the current hysteresis appear on the current-voltage
characteristics. The current hysteresis of the first type occurs at the bias
voltage below the resonant current peak and results from the accumulation of
electrons in the quantum well layer. The current hysteresis of the second type
appears at the bias voltage above the resonant current peak and is caused by
the creation of the quasi-bound state in the left contact region and the
resonant tunneling through this quasi-bound state. The physical interpretation
of both the types of the current hysteresis is further supported by the
analysis of the calculated self-consistent potential profiles and electron
density distributions. Based on these results we have shown that -- in certain
bias voltage and magnetic field ranges -- the spin polarization of the current
exhibits the plateau behavior with the nearly full spin polarization. This
property is very promising for possible applications in spintronics.",1103.0408v1
2017-05-26,On the Spin States of Habitable Zone Exoplanets Around M Dwarfs: The Effect of a Near-Resonant Companion,"One longstanding problem for the potential habitability of planets within M
dwarf systems is their likelihood to be tidally locked in a synchronously
rotating spin state. This problem thus far has largely been addressed only by
considering two objects: the star and the planet itself. However, many systems
have been found to harbor multiple planets, with some in or very near to
mean-motion resonances. The presence of a planetary companion near a
mean-motion resonance can induce oscillatory variations in the mean-motion of
the planet, which we demonstrate can have significant effects on the spin-state
of an otherwise synchronously rotating planet. In particular, we find that a
planetary companion near a mean-motion resonance can excite the spin states of
planets in the habitable zone of small, cool stars, pushing otherwise
synchronously rotating planets into higher amplitude librations of the spin
state, or even complete circulation resulting in effective stellar days with
full surface coverage on the order of years or decades. This increase in
illuminated area can have potentially dramatic influences on climate, and thus
on habitability. We also find that the resultant spin state can be very
sensitive to initial conditions due to the chaotic nature of the spin state at
early times within certain regimes. We apply our model to two hypothetical
planetary systems inspired by the K00255 and TRAPPIST-1 systems, which both
have Earth-sized planets in mean-motion resonances orbiting cool stars.",1705.09685v3
2017-01-19,Obliquity evolution of the minor satellites of Pluto and Charon,"New Horizons mission observations show that the small satellites Styx, Nix,
Kerberos and Hydra, of the Pluto-Charon system, have not tidally spun-down to
near synchronous spin states and have high obliquities with respect to their
orbit about the Pluto-Charon binary (Weaver et al. 2016). We use a damped
mass-spring model within an N-body simulation to study spin and obliquity
evolution for single spinning non-round bodies in circumbinary orbit.
Simulations with tidal dissipation alone do not show strong obliquity
variations from tidally induced spin-orbit resonance crossing and this we
attribute to the high satellite spin rates and low orbital eccentricities.
However, a tidally evolving Styx exhibits intermittent obliquity variations and
episodes of tumbling. During a previous epoch where Charon migrated away from
Pluto, the minor satellites could have been trapped in orbital mean motion
inclination resonances. An outward migrating Charon induces large variations in
Nix and Styx's obliquities. The cause is a commensurability between the mean
motion resonance frequency and the spin precession rate of the spinning body.
As the minor satellites are near mean motion resonances, this mechanism could
have lifted the obliquities of all four minor satellites. The high obliquities
need not be primordial if the minor satellites were at one time captured into
mean motion resonances.",1701.05594v2
2020-07-06,Transverse and Longitudinal Spin-Torque Ferromagnetic Resonance for Improved Measurements of Spin-Orbit Torques,"Spin-torque ferromagnetic resonance (ST-FMR) is a common method used to
measure spin-orbit torques (SOTs) in heavy metal/ferromagnet bilayer
structures. In the course of a measurement, other resonant processes such as
spin pumping (SP) and heating can cause spin current or heat flows between the
layers, inducing additional resonant voltage signals via the inverse spin Hall
effect (ISHE) and Nernst effects (NE). In the standard ST-FMR geometry, these
extra artifacts exhibit a dependence on the angle of an in-plane magnetic field
that is identical to the rectification signal from the SOTs. We show
experimentally that the rectification and artifact voltages can be quantified
separately by measuring the ST-FMR signal transverse to the applied current
(i.e., in a Hall geometry) in addition to the usual longitudinal geometry. We
find that in Pt (6 nm)/CoFeB samples the contribution from the artifacts is
small compared to the SOT rectification signal for CoFeB layers thinner than 6
nm, but can be significant for thicker magnetic layers. We observe a sign
change in the artifact voltage as a function of CoFeB thickness that we suggest
may be due to a competition between a resonant heating effect and the SP/ISHE
contribution.",2007.02850v1
2023-06-09,Secular dynamics of stellar spin driven by planets inside Kozai-Lidov resonance,"In many exoplanetary systems with `hot Jupiters', it is observed that the
spin axes of host stars are highly misaligned to planetary orbital axes. In
this study, a possible channel is investigated for producing such a
misalignment under a hierarchical three-body system where the evolution of
stellar spin is subjected to the gravitational torque induced from the planet
inside Kozai--Lidov (KL) resonance. In particular, two special configurations
are explored in detail. The first one corresponds to the configuration with
planets at KL fixed points, and the second one corresponds to the
configurations with planets moving on KL librating cycles. When the planet is
located at the KL fixed point, the corresponding Hamiltonian model is of one
degree of freedom and there are three branches of libration centres for stellar
spin. When the planet is moving on KL cycles, the technique of Poincar\'e
section is taken to reveal global structures of stellar spin in phase space. To
understand the complex structures, perturbative treatments are adopted to study
rotational dynamics. It shows that analytical structures in phase portraits
under the resonant model can agree well with numerical structures arising in
Poincar\'e sections, showing that the complicated dynamics of stellar spin are
governed by the primary resonance under the unperturbed Hamiltonian model in
combination with the 2:1 (high-order and/or secondary) spin-orbit resonances.",2306.05639v1
2023-07-12,Cavity-mediated entanglement of parametrically driven spin qubits via sidebands,"We consider a pair of quantum dot-based spin qubits that interact via
microwave photons in a superconducting cavity, and that are also parametrically
driven by separate external electric fields. For this system, we formulate a
model for spin qubit entanglement in the presence of mutually off-resonant
qubit and cavity frequencies. We show that the sidebands generated via the
driving fields enable highly tunable qubit-qubit entanglement using only ac
control and without requiring the qubit and cavity frequencies to be tuned into
simultaneous resonance. The model we derive can be mapped to a variety of qubit
types, including detuning-driven one-electron spin qubits in double quantum
dots and three-electron resonant exchange qubits in triple quantum dots. The
high degree of nonlinearity inherent in spin qubits renders these systems
particularly favorable for parametric drive-activated entanglement. We
determine multiple common resonance conditions for the two driven qubits and
the cavity and identify experimentally relevant parameter regimes that enable
the implementation of entangling gates with suppressed sensitivity to cavity
photon occupation and decay. The parametrically driven sideband resonance
approach we describe provides a promising route toward scalability and
modularity in spin-based quantum information processing through drive-enabled
tunability that can also be implemented in micromagnet-free electron and hole
systems for spin-photon coupling.",2307.06067v1
2023-12-19,Cavity-resonated detection of spin polarization in a microfabricated atomic vapor cell,"We demonstrate continuous Pound-Drever-Hall (PDH) nondestructive monitoring
of the electron spin polarization of an atomic vapor in a microfabricated vapor
cell within an optical resonator. The two-chamber silicon and glass cell
contains $^{87}$Rb and 1.3 amagat of N$_{2}$ buffer gas, and is placed within a
planar optical resonator formed by two mirrors with dichroic dielectric
coatings to resonantly enhance the coupling to phase-modulated probe light near
the D$_2$ line at 780 nm. We describe the theory of signal generation in this
system, including the spin-dependent complex refractive index, cavity optical
transfer functions, and PDH signal response to spin polarization. We observe
cavity transmission and PDH signals across $\approx 200$ GHz of detuning around
the atomic resonance line. By resonant optical pumping on the 795 nm D$_1$
line, we observe spin-dependent cavity line shifts, in good agreement with
theory. We use the saturation of the line shift vs. optical pumping power to
calibrate the number density and efficiency of the optical pumping. In the
unresolved sideband regime, we observe quantum-noise-limited PDH readout of the
spin polarization density, with a flat noise floor of $9 \times 10^9$ spins
cm$^{-3}$ Hz$^{-1/2}$ for frequencies above 700 Hz. We note possible extensions
of the technique.",2312.12256v1
2010-12-17,Electrically detected magnetic resonance of neutral donors interacting with a two-dimensional electron gas,"We have measured the electrically detected magnetic resonance of
channel-implanted donors in silicon field-effect transistors in resonant X-
($9.7\:$GHz) and W-band ($94\:$GHz) microwave cavities, with corresponding
Zeeman fields of $0.35\:$T and $3.36\:$T, respectively. It is found that the
conduction electron resonance signal increases by two orders of magnitude from
X- to W-band, while the hyperfine-split donor resonance signals are enhanced by
over one order of magnitude. We rule out a bolometric origin of the resonance
signals, and find that direct spin-dependent scattering between the
two-dimensional electron gas and neutral donors is inconsistent with the
experimental observations. We propose a new polarization transfer model from
the donor to the conduction electrons as the main contributer to the spin
resonance signals observed.",1012.3811v1
2012-12-21,Detectability of the second resonance of low-scale string models at the LHC,"Low-scale string models are phenomenological models in String Theory, in
which the string scale M_s is of the order of TeV. String excited states which
are characteristic modes in low-scale string models can be observed as
resonances in dijet invariant mass distributions at the LHC. If a new heavy
resonance is discovered at the LHC, it is important to investigate whether the
resonance comes from low-scale string models. In this work, two analyses are
performed: One is observing higher spin degeneracy of string excited states by
an angular distribution analysis on the resonance, since the string resonance
consists of several degenerate states with different spins. The other is
observing second string excited states by a search for a second resonance in
dijet invariant mass distributions, since second string excited states have
characteristic masses of sqrt{2} times of masses of first string excited
states. As the result of Monte Carlo simulations assuming the 14 TeV LHC, we
give required luminosities for 5 sigma confirmation in each analysis, in case
of M_s = 4.5, 4.75 and 5 TeV.",1212.5372v3
2014-02-12,"Nuclear magnetic resonances in (In,Ga)As/GaAs quantum dots studied by resonant optical pumping","The photoluminescence polarizations of (In,Ga)As/GaAs quantum dots annealed
at different temperatures are studied as a function of external magnetic field
(Hanle curves). In these dependencies, remarkable resonant features appear due
to all-optical nuclear magnetic resonances (NMR) for optical excitation with
modulated circular polarization. Application of an additional radio-frequency
field synchronously with the polarization modulation strongly modifies the NMR
features. The resonances can be related to transitions between different
nuclear spin states split by the strain-induced gradient of the crystal field
and by the externally applied magnetic field. A theoretical model is developed
to simulate quadrupole and Zeeman splittings of the nuclear spins in a strained
quantum dot. Comparison with the experiment allows us to uniquely identify the
observed resonances. The large broadening of the NMR resonances is attributed
to variations of the quadrupole splitting within the quantum dot volume, which
is well described by the model.",1402.2727v2
2015-01-03,Instrument for in-situ orientation of superconducting thin-film resonators used for electron-spin resonance experiments,"When used in Electron-Spin Resonance (ESR) measurements, superconducting
thin-film resonators must be precisely oriented relative to the external
magnetic field in order to prevent the trapping of magnetic flux and the
associated degradation of resonator performance. We present a compact design
solution for this problem that allows in-situ control of the orientation of the
resonator at cryogenic temperatures. Tests of the apparatus show that when
proper alignment is achieved, there is almost no hysteresis in the field
dependence of the resonant frequency.",1501.01596v2
2022-08-12,Observation of magnetic Feshbach resonances between Cs and ${}^{173}$Yb,"We report the first observation of magnetic Feshbach resonances between
${}^{173}$Yb and $^{133}$Cs. In a mixture of Cs atoms prepared in the $(f=3,
m_f=3)$ state and unpolarized fermionic ${}^{173}$Yb we observe resonant atom
loss due to two sets of magnetic Feshbach resonances around 622~G and 702~G.
Resonances for individual Yb nuclear spin components $m_{i,\mathrm{Yb}}$ are
split by its interaction with the Cs electronic spin, which also provides the
main coupling mechanism for the observed resonances. The observed splittings
and relative resonance strengths are in good agreement with theoretical
predictions from coupled-channel calculations.",2208.06291v1
2013-07-30,Electrodynamics of a ring-shaped spiral resonator,"We present analytical, numerical and experimental investigations of
electromagnetic resonant modes of a compact monofilar Archimedean spiral
resonator shaped in a ring, with no central part. Planar spiral resonators are
interesting as components of metamaterials for their compact deep-subwavelength
size. Such resonators couple primarily to the magnetic field component of the
incident electromagnetic wave, offering properties suitable for magnetic
meta-atoms. Surprisingly, the relative frequencies of the resonant modes follow
the sequence of the odd numbers, despite the nearly identical boundary
conditions for electromagnetic fields at the extremities of the resonator. In
order to explain the observed spectrum of resonant modes, we show that the
current distribution inside the spiral satisfies a particular Carleman type
singular integral equation. By solving this equation, we obtain a set of
resonant frequencies. The analytically calculated resonance frequencies and the
current distributions are in good agreement with experimental data and the
results of numerical simulations. By using low-temperature laser scanning
microscopy of a superconducting spiral resonator, we compare the experimentally
visualized ac current distributions over the spiral with the calculated ones.
Theory and experiment agree well with each other. Our analytical model allows
for calculation of a detailed three-dimensional magnetic field structure of the
resonators.",1307.7959v1
2014-10-08,Tailoring dielectric resonator geometries for directional scattering and Huygens' metasurfaces,"In this paper we describe a methodology for tailoring the design of
metamaterial dielectric resonators, which represent a promising path toward
low-loss metamaterials at optical frequencies. We first describe a procedure to
decompose the far field scattered by subwavelength resonators in terms of
multipolar field components, providing explicit expressions for the multipolar
far fields. We apply this formulation to confirm that an isolated
high-permittivity cube resonator possesses frequency separated electric and
magnetic dipole resonances, as well as a magnetic quadrupole resonance in close
proximity to the electric dipole resonance. We then introduce multiple
dielectric gaps to the resonator geometry in a manner suggested by perturbation
theory, and demonstrate the ability to overlap the electric and magnetic dipole
resonances, thereby enabling directional scattering by satisfying the first
Kerker condition. We further demonstrate the ability to push the quadrupole
resonance away from the degenerate dipole resonances to achieve local behavior.
These properties are confirmed through the multipolar expansion and show that
the use of geometries suggested by perturbation theory is a viable route to
achieve purely dipole resonances for metamaterial applications such as
wave-front manipulation with Huygens' metasurfaces. Our results are fully
scalable across any frequency bands where high-permittivity dielectric
materials are available, including microwave, THz, and infrared frequencies.",1410.2315v2
2017-04-25,Unified Treatment of Spin Torques using a Coupled Magnetisation Dynamics and Three-Dimensional Spin Current Solver,"A three-dimensional spin current solver based on a generalised spin
drift-diffusion description, including the spin Hall effect, is integrated with
a magnetisation dynamics solver. The resulting model is shown to simultaneously
reproduce the spin-orbit torques generated using the spin Hall effect, spin
pumping torques generated by magnetisation dynamics in multilayers, as well as
the spin transfer torques acting on magnetisation regions with spatial
gradients, whilst field-like and spin-like torques are reproduced in a spin
valve geometry. Two approaches to modelling interfaces are analysed, one based
on the spin mixing conductance and the other based on continuity of spin
currents where the spin dephasing length governs the absorption of transverse
spin components. In both cases analytical formulas are derived for the
spin-orbit torques in a heavy metal / ferromagnet bilayer geometry, showing in
general both field-like and damping-like torques are generated. The limitations
of the analytical approach are discussed, showing that even in a simple bilayer
geometry, due to the non-uniformity of the spin currents, a full
three-dimensional treatment is required. Finally the model is applied to the
quantitative analysis of the spin Hall angle in Pt by reproducing published
experimental data on the ferromagnetic resonance linewidth in the bilayer
geometry.",1704.07758v2
2019-06-24,Origin of the chromospheric three-minute oscillations in sunspot umbrae,"Sunspot umbrae show a change in the dominant period of their oscillations
from five minutes in the photosphere to three minutes in the chromosphere. In
this paper, we explore the two most popular models proposed to explain the
three-minute oscillations: the chromospheric acoustic resonator and the
propagation of waves with frequency above the cutoff value directly from lower
layers. We employ numerical simulations of wave propagation from the solar
interior to the corona. Waves are driven by a piston at the bottom boundary. We
have performed a parametric study of the measured chromospheric power spectra
in a large number of numerical simulations with differences in the driving
method, the height of the transition region (or absence of transition region),
the strength of the vertical magnetic field, and the value of the radiative
cooling time. We find that both mechanisms require the presence of waves with
period in the three-minute band at the photosphere. These waves propagate
upward and their amplitude increases due to the drop of the density. Their
amplification is stronger than that of evanescent low-frequency waves. This
effect is enough to explain the dominant period observed in chromospheric
spectral lines. However, waves are partially trapped between the photosphere
and the transition region, forming an acoustic resonator. This chromospheric
resonant cavity strongly enhances the power in the three-minute band. The
chromospheric acoustic resonator model and the propagation of waves in the
three-minute band directly from the photosphere can explain the observed
chromospheric three-minute oscillations. They are both important in different
scenarios. Resonances are produced by waves trapped between the temperature
minimum and the transition region. Strong magnetic fields and radiative losses
remove energy from the waves inside the cavity, resulting in weaker amplitude
resonances.",1906.09797v1
2023-03-14,Electromagnetic Waves Propagation along Tangentially Magnetised Bihyrotropic Layer (with Example of Spin Waves in Ferrite Plate),"Analytically, without magnetostatic approximation, the problem of
electromagnetic wave propagation along arbitrary direction in a tangentially
magnetized bihyrotropic layer has been solved. It is found that one can bring
the Maxwell equations for this problem to the fourth order differential
equation and the obtained biquadratic characteristic equation determines two
different wave numbers kx21 and kx22 describing the wave distribution over the
layer thickness. The dispersion equation describing wave propagation in the
bihyrotropic layer was obtained for the case of real kx21 and kx22 values. It
is shown that in a ferrite plate, which is a special case of a bihyrotropic
layer, three types of wave distribution over the plate thickness can take
place: surface-surface (when kx21 and kx22 are real numbers), volume-surface
(kx21 is imaginary and kx22 is real) and volume-volume distribution (kx21 and
kx22 are imaginary numbers). Characteristics of the surface spin wave in
ferrite plate are investigated. It is found that dependences of the wave
numbers kx21 and kx22 on the wave vector orientation are significantly
different from the similar magnetostatic dependence for a large part of the
wave spectrum.",2303.08800v1
2023-08-07,Water-Wave Vortices and Skyrmions,"Topological wave structures -- phase vortices, skyrmions, merons, etc. -- are
attracting enormous attention in a variety of quantum and classical wave
fields. Surprisingly, these structures have never been properly explored in the
most obvious example of classical waves: water-surface (gravity-capillary)
waves. Here we fill this gap and describe: (i) water-wave vortices of different
orders carrying quantized angular momentum with orbital and spin contributions,
(ii) skyrmion lattices formed by the instantaneous displacements of the
water-surface particles in wave interference, (iii) meron (half-skyrmion)
lattices formed by the spin density vectors, as well as (iv) spatiotemporal
water-wave vortices and skyrmions. We show that all these topological entities
can be readily generated in linear water-wave interference experiments. Our
findings can find applications in microfluidics and show that water waves can
be employed as an attainable playground for emulating universal topological
wave phenomena.",2308.03520v2
2002-07-06,"Unified Theory of Bivacuum, Particles Duality, Fields & Time. New Bivacuum Mediated Interaction, Overunity Devices, Cold Fusion & Nucleosynthesis","New concept of Bivacuum is introduced, as a dynamic matrix of the Universe,
composed from sub-quantum particles and antiparticles, forming vortical
structures. These structures are presented by continuum of dipoles, each dipole
containing a pair of correlated torus and antitorus: V(+) and V(-) of the
opposite energy/mass, spin, charge and magnetic moments, compensating each
other. The rest mass and charge of sub-elementary fermions or antifermions is a
result of Bivacuum dipoles opposite symmetry shifts. Their fusion to triplets
follows by elementary particles and antiparticles origination. The [corpuscle
(C) - wave (W)] duality is a result of correlated beats between the 'actual'
and 'complementary' states of sub-elementary fermions of triplets. It is shown,
that Principle of least action, the 2d and 3d laws of thermodynamics can be a
consequences of forced combinational resonance between positive and negative
virtual pressure waves (VPW+/-) of Bivacuum and [C-W] pulsation of elementary
particles. The quantum entanglement, mediated by virtual microtubules, composed
from Bivacuum dipoles, connecting remote particles, is a result of such
Bivacuum-matter interaction. The pace of time for any closed system is
determined by pace of kinetic energy change of this system. The proposed
mechanism of overunity devices can be provided by the electrons acceleration,
induced by their resonant interaction with high frequency positive and negative
VPW+/- in pull-in range conditions. The latter can be excited by pulsing
currents and fields. The mechanism of overheating and cold fusion in
electrolytic cells without violation of energy conservation is proposed also.",0207027v5
2015-04-09,Measurement of double polarisation asymmetries in $ω$-photoproduction,"The first measurements of the beam-target-helicity-asymmetries $E$ and $G$ in
the photoproduction of $\omega$-mesons off protons at the CBELSA/TAPS
experiment are reported. $E$ ($G$) was measured using circularly (linearly)
polarised photons and a longitudinally polarised target. $E$ was measured over
the photon energy range from close to threshold ($E_\gamma = 1108$~MeV) to
$E_\gamma = 2300$~MeV and $G$ at a single energy interval of $1108 < E_\gamma
<1300$~MeV. Both measurements cover the full solid angle. The observables $E$
and $G$ are highly sensitive to the contribution of baryon resonances, with $E$
acting as a helicity filter in the $s$-channel. The new results indicate
significant $s$-channel resonance contributions together with contributions
from $t$-channel exchange processes. A partial wave analysis reveals strong
contributions from the partial waves with spin-parity $J^P=3/2^+, 5/2^+$, and
$3/2^-$.",1504.02221v2
2019-03-09,Spin-wave thermodynamics of square-lattice antiferromagnets revisited,"Modifying the conventional spin-wave theory in a novel manner based on the
Wick decomposition, we present an elaborate thermodynamics of square-lattice
quantum antiferromagnets. Our scheme is no longer accompanied by the notorious
problem of an artificial transition to the paramagnetic state inherent in
modified spin waves in the Hartree-Fock approximation. In the cases of spin
$\frac{1}{2}$ and spin $1$, various modified-spin-wave findings for the
internal energy, specific heat, static uniform susceptibility, and dynamic
structure factor are not only numerically compared with quantum Monte Carlo
calculations and Lanczos exact diagonalizations but also analytically expanded
into low-temperature series. Modified spin waves interacting via the Wick
decomposition provide reliable thermodynamics over the whole temperature range
of absolute zero to infinity. Adding higher-order spin couplings such as ring
exchange interaction to the naivest Heisenberg Hamiltonian, we precisely
reproduce inelastic-neutron-scattering measurements of the
high-temperature-superconductor-parent antiferromagnet
$\mathrm{La}_2\mathrm{CuO}_4$. Modifying Dyson-Maleev bosons combined with
auxiliary pseudofermions also yields thermodynamics of square-lattice
antiferromagnets free from thermal breakdown, but it is less precise unless
temperature is sufficiently low. Applying all the schemes to layered
antiferromagnets as well, we discuss the advantages and disadvantages of
modified spin-wave and combined boson-pseudofermion representations.",1903.03769v1
2022-03-24,Writable spin wave nanochannels in an artificial-spin-ice-mediated ferromagnetic thin film,"Magnonics, which employs spin-waves to transmit and process information, is a
promising venue for low-power data processing. One of the major challenges is
the local control of the spin-wave propagation path. Here, we introduce the
concept of writable magnonics by taking advantage of the highly flexible
reconfigurability and rewritability of artificial spin ice systems. Using
micromagnetic simulations, we show that globally switchable spin-wave
propagation and the locally writable spin-wave nanochannels can be realized in
a ferromagnetic thin film underlying an artificial pinwheel spin ice. The
rewritable magnonics enabled by reconfigurable spin wave nanochannels provides
a unique setting to design programmable magnonic circuits and logic devices for
ultra-low power applications.",2203.12812v2
2006-02-14,The three-wave coupling coefficients for a cold magnetized plasma,"The resonant interaction between three waves in a uniform magnetized plasma
is considered. Using the somewhat inaccessible result of the general theory we
deduce the explicit expressions for the coupling coefficients of a cold
magnetized two-component plasma.",0602089v1
2006-05-19,Nonlinear interaction between three inertial Alfvén waves,"The resonant coupling between Alfv\'{e}n waves is reconsidered. New results
are found for cold plasmas there temperature effects are negligible.",0605169v1
2012-07-06,"Hadron Spectroscopy, Results and Ideas","New results on the spectrum of nucleon resonances from the Bonn-Gatchina
partial wave analysis are presented, and possible interpretations are
discussed.",1207.1601v1
2014-07-24,More Kronoseismology with Saturn's rings,"In a previous paper (Hedman and Nicholson 2013), we developed tools that
allowed us to confirm that several of the waves in Saturn's rings were likely
generated by resonances with fundamental sectoral normal modes inside Saturn
itself. Here we use these same tools to examine eight additional waves that are
probably generated by structures inside the planet. One of these waves appears
to be generated by a resonance with a fundamental sectoral normal mode with
azimuthal harmonic number m=10. If this attribution is correct, then the m=10
mode must have a larger amplitude than the modes with m=5-9, since the latter
do not appear to generate strong waves. We also identify five waves with
pattern speeds between 807 degrees/day and 834 degrees/day. Since these pattern
speeds are close to the planet's rotation rate, they probably are due to
persistent gravitational anomalies within the planet. These waves are all found
in regions of enhanced optical depth known as plateaux, but surprisingly the
surface mass densities they yield are comparable to the surface mass densities
of the background C ring. Finally, one wave appears to be a one-armed spiral
pattern whose rotation rate suggests it is generated by a resonance with a
structure inside Saturn, but the nature of this perturbing structure remains
unclear. Strangely, the resonant radius for this wave seems to be drifting
inwards at an average rate of 0.8 km/year over the last thirty years, implying
that the relevant planetary oscillation frequency has been steadily increasing.",1407.6702v2
2017-07-17,Electrostatic and whistler instabilities excited by an electron beam,"The electron beam-plasma system is ubiquitous in the space plasma
environment. Here, using a Darwin particle-in-cell method, the excitation of
electrostatic and whistler instabilities by a gyrating electron beam is studied
in support of recent laboratory experiments. It is assumed that the total
plasma frequency $\omega_{pe}$ is larger than the electron cyclotron frequency
$\Omega_e$. The fast-growing electrostatic beam-mode waves saturate in a few
plasma oscillations by slowing down and relaxing the electron beam parallel to
the background magnetic field. Upon their saturation, the finite amplitude
electrostatic beam-mode waves can resonate with the tail of the background
thermal electrons and accelerate them to the beam parallel velocity. The
slower-growing whistler waves are excited in primarily two resonance modes: (a)
through Landau resonance due to the inverted slope of the beam electrons in the
parallel velocity; (b) through cyclotron resonance by scattering electrons to
both lower pitch angles and smaller energies. It is demonstrated that, for a
field-aligned beam, the whistler instability can be suppressed by the
electrostatic instability due to a faster energy transfer rate between beam
electrons and the electrostatic waves. Such a competition of growth between
whistler and electrostatic waves depends on the ratio of
$\omega_{pe}/\Omega_e$. In terms of wave propagation, beam-generated
electrostatic waves are confined to the beam region whereas beam-generated
whistler waves transport energy away from the beam.",1707.05346v1
2018-09-28,Strong instability of standing waves for a system NLS with quadratic interaction,"We study the strong instability of standing waves for a system of nonlinear
Schr\""odinger equations with quadratic interaction under the mass resonance
condition in dimension $d=5$.",1810.00676v1
2020-12-11,Mixed properties of magnetohydrodynamic waves undergoing resonant absorption in the cusp continuum,"Observations of magnetohydrodynamic (MHD) waves in the structured solar
atmosphere have shown that these waves are damped and can thus contribute to
atmospheric heating. In this paper, we focus on the damping mechanism of
resonant absorption in the cusp continuum. This process takes places when waves
travel through an inhomogeneous plasma. Our aim is to determine the properties
of MHD waves undergoing resonant absorption in the cusp continuum in the
transition layer of a cylindrical solar atmospheric structure, such as a
photospheric pore or a coronal loop. Depending on which quantities dominate,
one can assess what type of classical MHD wave the modes in question resemble
most. In order to study the properties of these waves, we analytically
determine the spatial profiles of compression, displacement, and vorticity for
waves with frequencies in the cusp continuum, which undergo resonant
absorption. We confirm these analytical derivations via numerical calculations
of the profiles in the resistive MHD framework. We show that the dominant
quantities for the modes in the cusp continuum are the displacement parallel to
the background magnetic field and the vorticity component in the azimuthal
direction (i.e. perpendicular to the background magnetic field and along the
loop boundary).",2012.06303v1
2022-07-23,Dynamics of NEMS Resonators across Dissipation Limits,"The oscillatory dynamics of nanoelectromechanical systems (NEMS) is at the
heart of many emerging applications in nanotechnology. For common NEMS, such as
beams and strings, the oscillatory dynamics is formulated using a
dissipationless wave equation derived from elasticity. Under a harmonic ansatz,
the wave equation gives an undamped free vibration equation; solving this
equation with the proper boundary conditions provides the undamped
eigenfunctions with the familiar standing wave patterns. Any harmonically
driven solution is expressible in terms of these undamped eigenfunctions. Here,
we show that this formalism becomes inconvenient as dissipation increases. To
this end, we experimentally map out the position- and frequency-dependent
oscillatory motion of a NEMS string resonator driven linearly by a
non-symmetric force on one end at different dissipation limits. At low
dissipation (high Q factor), we observe sharp resonances with standing wave
patterns that closely match the eigenfunctions of an undamped string. With a
slight increase in dissipation, the standing wave patterns become lost and
waves begin to propagate along the nanostructure. At large dissipation (low Q
factor), these propagating waves become strongly attenuated and display little,
if any, resemblance to the undamped string eigenfunctions. A more efficient and
intuitive description of the oscillatory dynamics of a NEMS resonator can be
obtained by superposition of waves propagating along the nanostructure.",2207.11411v1
2016-01-30,Strongly-coupled nanotube electromechanical resonators,"Coupling an electromechanical resonator with carbon-nanotube quantum dots is
a significant method to control both the electronic charge and the spin quantum
states. By exploiting a novel micro-transfer technique, we fabricate two
strongly-coupled and electrically-tunable mechanical resonators on a single
carbon nanotube for the first time. The frequency of the two resonators can be
individually tuned by the bottom gates, and strong coupling is observed between
the electron charge and phonon modes of each resonator. Furthermore, the
conductance of either resonator can be nonlocally modulated by the phonon modes
in the other resonator. Strong coupling is observed between the phonon modes of
the two resonators, which provides an effective long distance electron-electron
interaction. The generation of phonon-mediated-spin entanglement is also
theoretically analyzed for the two resonators. This strongly-coupled nanotube
electromechanical resonator array provides an experimental platform for future
studies of the coherent electron-phonon interaction, the phonon mediated
long-distance electron interaction, and entanglement state generation.",1602.00082v1
2022-09-28,A novel Machine-Learning method for spin classification of neutron resonances,"The performance of nuclear reactors and other nuclear systems depends on a
precise understanding of the neutron interaction cross sections for materials
used in these systems. These cross sections exhibit resonant structure whose
shape is determined in part by the angular momentum quantum numbers of the
resonances. The correct assignment of the quantum numbers of neutron resonances
is, therefore, paramount. In this project, we apply machine learning to
automate the quantum number assignments using only the resonances' energies and
widths and not relying on detailed transmission or capture measurements. The
classifier used for quantum number assignment is trained using stochastically
generated resonance sequences whose distributions mimic those of real data. We
explore the use of several physics-motivated features for training our
classifier. These features amount to out-of-distribution tests of a given
resonance's widths and resonance-pair spacings. We pay special attention to
situations where either capture widths cannot be trusted for classification
purposes or where there is insufficient information to classify resonances by
the total spin $J$. We demonstrate the efficacy of our classification approach
using simulated and actual $^{52}$Cr resonance data.",2209.14403v2
2018-09-05,Constraining black-hole spins with gravitational wave observations,"The observation of gravitational-wave signals from merging black-hole
binaries enables direct measurement of the properties of the black holes. An
individual observation allows measurement of the black-hole masses, but only
limited information about either the magnitude or orientation of the black hole
spins is available, primarily due to the degeneracy between measurements of
spin and binary mass ratio. Using the first six black-hole merger observations,
we are able to constrain the distribution of black-hole spins. We perform model
selection between a set of models with different spin population models
combined with a power-law mass distribution to make inferences about the spin
distribution. We assume a fixed power-law mass distribution on the black holes,
which is supported by the data and provides a realistic distribution of binary
mass-ratio. This allows us to accurately account for selection effects due to
variations in the signal amplitude with spin magnitude, and provides an
improved inference on the spin distribution. We conclude that the first six
LIGO and Virgo observations (Abbott et al. 2016a, 2017a,b,c) disfavour highly
spinning black holes against low spins by an odds-ratio of 15:1; thus providing
strong constraints on spin magnitudes from gravitational-wave observations.
Furthermore, we are able to rule out a population of binaries with completely
aligned spins, even when the spins of the individual black holes are low, at an
odds ratio of 22,000:1, significantly strengthening earlier evidence against
aligned spins (Farr et al. 2017). These results provide important information
that will aid in our understanding on the formation processes of black-holes.",1809.01401v2
2014-09-03,Theory of coupled spin-charge transport due to spin-orbit interaction in inhomogeneous two-dimensional electron liquids,"Spin-orbit interactions in two-dimensional electron liquids are responsible
for many interesting transport phenomena in which particle currents are
converted to spin polarizations and spin currents and viceversa. Prime examples
are the spin Hall effect, the Edelstein effect, and their inverses. By similar
mechanisms it is also possible to partially convert an optically induced
electron-hole density wave to a spin density wave and viceversa. In this paper
we present a unified theoretical treatment of these effects based on quantum
kinetic equations that include not only the intrinsic spin-orbit coupling from
the band structure of the host material, but also the spin-orbit coupling due
to an external electric field and a random impurity potential. The
drift-diffusion equations we derive in the diffusive regime are applicable to a
broad variety of experimental situations, both homogeneous and non-homogeneous,
and include on equal footing ""skew scattering"" and ""side-jump"" from
electron-impurity collisions. As a demonstration of the strength and usefulness
of the theory we apply it to the study of several effects of current
experimental interest: the inverse Edelstein effect, the spin-current swapping
effect, and the partial conversion of an electron-hole density wave to a spin
density wave in a two-dimensional electron gas with Rashba and Dresselhaus
spin-orbit couplings, subject to an electric field.",1409.1202v1
2005-06-20,Nonlinear spin relaxation in strongly nonequilibrium magnets,"A general theory is developed for describing the nonlinear relaxation of spin
systems from a strongly nonequilibrium initial state, when, in addition, the
sample is coupled to a resonator. Such processes are characterized by nonlinear
stochastic differential equations. This makes these strongly nonequilibrium
processes principally different from the spin relaxation close to an
equilibrium state, which is represented by linear differential equations. The
consideration is based on a realistic microscopic Hamiltonian including the
Zeeman terms, dipole interactions, exchange interactions, and a single-site
anisotropy. The influence of cross correlations between several spin species is
investigated. The critically important function of coupling between the spin
system and a resonant electric circuit is emphasized. The role of all main
relaxation rates is analyzed. The phenomenon of self-organization of transition
coherence in spin motion, from the quantum chaotic stage of incoherent
fluctuations, is thoroughly described. Local spin fluctuations are found to be
the triggering cause for starting the spin relaxation from an incoherent
nonequilibrium state. The basic regimes of collective coherent spin relaxation
are studied.",0506489v1
2009-08-03,A quantum spin transducer based on nano electro-mechancial resonator arrays,"Implementation of quantum information processing faces the contradicting
requirements of combining excellent isolation to avoid decoherence with the
ability to control coherent interactions in a many-body quantum system. For
example, spin degrees of freedom of electrons and nuclei provide a good quantum
memory due to their weak magnetic interactions with the environment. However,
for the same reason it is difficult to achieve controlled entanglement of spins
over distances larger than tens of nanometers. Here we propose a universal
realization of a quantum data bus for electronic spin qubits where spins are
coupled to the motion of magnetized mechanical resonators via magnetic field
gradients. Provided that the mechanical system is charged, the magnetic moments
associated with spin qubits can be effectively amplified to enable a coherent
spin-spin coupling over long distances via Coulomb forces. Our approach is
applicable to a wide class of electronic spin qubits which can be localized
near the magnetized tips and can be used for the implementation of hybrid
quantum computing architectures.",0908.0316v1
2009-09-02,Spin relaxation and combined resonance in two-dimensional electron systems with spin-orbit disorder,"Disorder in spin-orbit (SO) coupling is an important feature of real
low-dimensional electron structures. We study spin relaxation due to such a
disorder as well as resulting abilities of spin manipulation. The spin
relaxation reveals quantum effects when the spatial scale of the randomness is
smaller than the electron wavelength. Due to the disorder in SO coupling, a
time-dependent external electric field generates a spatially random
spin-dependent perturbation. The resulting electric dipole spin resonance in a
two-dimensional electron gas leads to spin injection in a frequency range of
the order of the Fermi energy. These effects can be important for possible
applications in spintronics.",0909.0352v1
2009-10-08,Proposal for Efficient Generation of Spin-Polarized Current in Silicon,"We propose a spin-dependent resonant tunneling structure to efficiently
inject spin-polarized current into silicon (Si). By means of a heavily doped
polycrystalline Si (Poly-Si) between the ferromagnetic metal (FM) and Si to
reduce the Schottky barrier resistance, we estimated raising the tunneling
current density up to $10^8$Am$^{-2}$. The small Fermi sea of the charge
carriers in Si focuses the tunneling electrons to the resonant spin states
within a small region of transverse momentum in the ferromagnet which creates
the spin polarization of the current. Because of the large exchange splitting
between the spin up and down bands, the decay of the spin current is explained
in terms of scattering out of the focused beam. The spin polarization in the
current survives only if the thickness of the FM-layer is smaller than the
spin-diffusion length estimated from that cause.",0910.1611v2
2010-04-01,Electron spin dynamics and electron spin resonance in graphene,"A theory of spin relaxation in graphene including intrinsic, Bychkov-Rashba,
and ripple spin-orbit coupling is presented. We find from spin relaxation data
by Tombros et al. [Nature 448, 571 (2007).] that intrinsic spin-orbit coupling
dominates over other contributions with a coupling constant of 3.7 meV.
Although it is 1-3 orders of magnitude larger than those obtained from first
principles, we show that comparable values are found for other honeycomb
systems, MgB2 and LiC6; the latter is studied herein by electron spin resonance
(ESR). We predict that spin coherence is longer preserved for spins
perpendicular to the graphene plane, which is beneficial for spintronics. We
identify experimental conditions when bulk ESR is realizable on graphene.",1004.0210v1
2010-10-08,Time-resolved detection of spin-transfer-driven ferromagnetic resonance and spin torque measurement in magnetic tunnel junctions,"Several experimental techniques have been introduced in recent years in
attempts to measure spin transfer torque in magnetic tunnel junctions (MTJs).
The dependence of spin torque on bias is important for understanding
fundamental spin physics in magnetic devices and for applications. However,
previous techniques have provided only indirect measures of the torque and
their results to date for the bias dependence are qualitatively and
quantitatively inconsistent. Here we demonstrate that spin torque in MTJs can
be measured directly by using time-domain techniques to detect resonant
magnetic precession in response to an oscillating spin torque. The technique is
accurate in the high-bias regime relevant for applications, and because it
detects directly small-angle linear-response magnetic dynamics caused by spin
torque it is relatively immune to artifacts affecting competing techniques. At
high bias we find that the spin torque vector differs markedly from the simple
lowest-order Taylor series approximations commonly assumed.",1010.1777v1
2011-10-10,Spin Manipulation and Relaxation in Spin-Orbit Qubits,"We derive a generalized form of the Electric Dipole Spin Resonance (EDSR)
Hamiltonian in the presence of the spin-orbit interaction for single spins in
an elliptic quantum dot (QD) subject to an arbitrary (in both direction and
magnitude) applied magnetic field. We predict a nonlinear behavior of the Rabi
frequency as a function of the magnetic field for sufficiently large Zeeman
energies, and present a microscopic expression for the anisotropic electron
g-tensor. Similarly, an EDSR Hamiltonian is devised for two spins confined in a
double quantum dot (DQD), where coherent Rabi oscillations between the singlet
and triplet states are induced by jittering the inter-dot distance at the
resonance frequency. Finally, we calculate two-electron-spin relaxation rates
due to phonon emission, for both in-plane and perpendicular magnetic fields.
Our results have immediate applications to current EDSR experiments on nanowire
QDs, g-factor optimization of confined carriers, and spin decay measurements in
DQD spin-orbit qubits.",1110.2193v1
2012-11-12,Dressed-State Polarization Transfer between Bright & Dark Spins in Diamond,"Under ambient conditions, spin impurities in solid-state systems are found in
thermally-mixed states and are optically ""dark"", i.e., the spin states cannot
be optically controlled. Nitrogen-vacancy (NV) centers in diamond are an
exception in that the electronic spin states are ""bright"", i.e., they can be
polarized by optical pumping, coherently manipulated with spin-resonance
techniques, and read out optically, all at room temperature. Here we
demonstrate a dressed-state, double-resonance scheme to transfer polarization
from bright NV electronic spins to dark substitutional-Nitrogen (P1) electronic
spins in diamond. This polarization-transfer mechanism could be used to cool a
mesoscopic bath of dark spins to near-zero temperature, thus providing a
resource for quantum information and sensing, and aiding studies of quantum
effects in many-body spin systems.",1211.2749v1
2013-01-31,Effects of Transverse Magnetic Anisotropy on Current-Induced Spin Switching,"Spin-polarized transport through bistable magnetic adatoms or single-molecule
magnets (SMMs), which exhibit both uniaxial and transverse magnetic anisotropy,
is considered theoretically. The main focus is on the impact of transverse
anisotropy on transport characteristics and the adatom's/SMM's spin. In
particular, we analyze the role of quantum tunneling of magnetization (QTM) in
the mechanism of the current-induced spin switching, and show that the QTM
phenomenon becomes revealed as resonant peaks in the average values of the
molecule's spin and in the charge current. These features appear at some
resonant fields and are observable when at least one of the electrodes is
ferromagnetic. We also show that the conductance generally depends on the
relative orientation of the average adatom's/SMM's spin and electrode's
magnetic moment. This spin-valve like magnetoresistance effect can be used to
control spin switching of the adatom's/SMM's spin.",1302.1074v1
2013-11-23,Electron spin resonance and spin-valley physics in a silicon double quantum dot,"Silicon quantum dots are a leading approach for solid-state quantum bits.
However, developing this technology is complicated by the multi-valley nature
of silicon. Here we observe transport of individual electrons in a silicon
CMOS-based double quantum dot under electron spin resonance. An anticrossing of
the driven dot energy levels is observed when the Zeeman and valley splittings
coincide. A detected anticrossing splitting of 60 MHz is interpreted as a
direct measure of spin and valley mixing, facilitated by spin-orbit interaction
in the presence of non-ideal interfaces. A lower bound of spin dephasing time
of 63 ns is extracted. We also describe a possible experimental evidence of an
unconventional spin-valley blockade, despite the assumption of non-ideal
interfaces. This understanding of silicon spin-valley physics should enable
better control and read-out techniques for the spin qubits in an all CMOS
silicon approach.",1311.5937v2
2016-10-21,Spin transport and dynamics in all-oxide perovskite La$_{2/3}$Sr$_{1/3}$MnO$_3$/SrRuO$_3$ bilayers probed by ferromagnetic resonance,"Thin films of perovskite oxides offer the possibility of combining emerging
concepts of strongly correlated electron phenomena and spin current in magnetic
devices. However, spin transport and magnetization dynamics in these complex
oxide materials are not well understood. Here, we experimentally quantify spin
transport parameters and magnetization damping in epitaxial perovskite
ferromagnet/paramagnet bilayers of La$_{2/3}$Sr$_{1/3}$MnO$_3$/SrRuO$_3$
(LSMO/SRO) by broadband ferromagnetic resonance spectroscopy. From the SRO
thickness dependence of Gilbert damping, we estimate a short spin diffusion
length of $\lesssim$1 nm in SRO and an interfacial spin-mixing conductance
comparable to other ferromagnet/paramagnetic-metal bilayers. Moreover, we find
that anisotropic non-Gilbert damping due to two-magnon scattering also
increases with the addition of SRO. Our results demonstrate LSMO/SRO as a
spin-source/spin-sink system that may be a foundation for examining
spin-current transport in various perovskite heterostructures.",1610.06661v1
2020-04-03,Spin-Excitations Anisotropy in the Bilayer Iron-Based Superconductor CaKFe$_4$As$_4$,"We use polarized inelastic neutron scattering to study the spin-excitations
anisotropy in the bilayer iron-based superconductor CaKFe$_4$As$_4$ ($T_c$ = 35
K). In the superconducting state, both odd and even $L-$modulations of spin
resonance have been observed in our previous unpolarized neutron scattering
experiments (T. Xie {\it et al.} Phys. Rev. Lett. {\bf 120}, 267003 (2018)).
Here we find that the high-energy even mode ($\sim 18$ meV) is isotropic in
spin space, but the low-energy odd modes consist of a $c-$axis polarized mode
around 9 meV along with another partially overlapped in-plane mode around 12
meV. We argue that such spin anisotropy is induced by the spin-orbit coupling
in the spin-vortex-type fluctuations of this unique compound. The spin
anisotropy is strongly affected by the superconductivity, where it is weak
below 6 meV in the normal state and then transferred to higher energy and
further enhanced in the odd mode of spin resonance below $T_c$.",2004.01405v1
2017-02-13,Spin Pumping and Inverse Spin Hall Voltages from Dynamical Antiferromagnets,"Dynamical antiferromagnets pump spins efficiently into adjacent conductors as
ferromagnets. The high antiferromagnetic resonance frequencies represent a
challenge for experimental detection, but magnetic fields can reduce these
resonance frequencies. We compute the inverse spin Hall voltages resulting from
dynamical spin excitations as a function of a magnetic field along the easy
axis and the polarization of the driving AC magnetic field perpendicular to the
easy axis. We consider the insulating antiferromagnets MnF$_2$, FeF$_2$, and
NiO. Near the spin-flop transition, there is a significant enhancement of the
DC spin pumping and inverse spin Hall voltage for the uniaxial antiferromagnets
MnF$_2$ and FeF$_2$. In the biaxial NiO, the voltages are much weaker, and
there is no spin-flop enhancement of the DC component.",1702.03779v1
2020-09-03,Parallel selective nuclear spin addressing for fast high-fidelity quantum gates,"Due to their long coherence times, nuclear spins have gained considerable
attention as physical qubits. Two-qubit gates between nuclear spins of distinct
resonance frequencies can be mediated by electron spins, usually employing a
sequence of electron-nuclear gates. Here we present a different approach
inspired by, but not limited to, NV centers in diamond and discuss possible
applications. To this end we generalize external electron spin control
sequences for nuclear spin initialization and hyperpolarization to achieve the
simultaneous control of distinct nuclear spins via an electron spin. This
approach results in efficient entangling gates that, compared to standard
techniques, reduce the gate time by more than 50% when the gate time is limited
by off-resonant coupling to other spins, and by up to 22% when the gate time is
limited by small electron-nuclear coupling.",2009.01727v2
2019-07-11,Image of dynamic local exchange interactions in the dc magnetoresistance of spin-polarized current through a dopant,"We predict strong, dynamical effects in the dc magnetoresistance of current
flowing from a spin-polarized electrical contact through a magnetic dopant in a
nonmagnetic host. Using the stochastic Liouville formalism we calculate
clearly-defined resonances in the dc magnetoresistance when the applied
magnetic field matches the exchange interaction with a nearby spin. At these
resonances spin precession in the applied magnetic field is canceled by spin
evolution in the exchange field, preserving a dynamic bottleneck for spin
transport through the dopant. Similar features emerge when the dopant spin is
coupled to nearby nuclei through the hyperfine interaction. These features
provide a precise means of measuring exchange or hyperfine couplings between
localized spins near a surface using spin-polarized scanning tunneling
microscopy, without any ac electric or magnetic fields, even when the exchange
or hyperfine energy is orders of magnitude smaller than the thermal energy.",1907.05509v1
2020-12-02,Nuclear spin readout in a cavity-coupled hybrid quantum dot-donor system,"Nuclear spins show long coherence times and are well isolated from the
environment, which are properties making them promising for quantum information
applications. Here, we present a method for nuclear spin readout by probing the
transmission of a microwave resonator. We consider a single electron in a
silicon quantum dot-donor device interacting with a microwave resonator via the
electric dipole coupling and subjected to a homogeneous magnetic field and a
transverse magnetic field gradient. In our scenario, the electron spin
interacts with a $^{31}\mathrm{P}$ defect nuclear spin via the hyperfine
interaction. We theoretically investigate the influence of the P nuclear spin
state on the microwave transmission through the cavity and show that nuclear
spin readout is feasible with current state-of-the-art devices. Moreover, we
identify optimal readout points with strong signal contrast to facilitate the
experimental implementation of nuclear spin readout. Furthermore, we
investigate the potential for achieving coherent excitation exchange between a
nuclear spin qubit and cavity photons.",2012.01322v2
2021-03-09,Self-induced spin-orbit torques in metallic ferromagnets,"We present a phenomenological theory of spin-orbit torques in a metallic
ferromagnet with spin-relaxing boundaries. The model is rooted in the coupled
diffusion of charge and spin in the bulk of the ferromagnet, where we account
for the anomalous Hall effects as well as the anisotropic magnetoresistance in
the corresponding constitutive relations for both charge and spin sectors. The
diffusion equations are supplemented with suitable boundary conditions
reflecting the spin-sink capacity of the environment. In inversion-asymmetric
heterostructures, the uncompensated spin accumulation exerts a dissipative
torque on the order parameter, giving rise to a current-dependent linewidth in
the ferromagnetic resonance with a characteristic angular dependence. We
compare our model to recent spin-torque ferromagnetic resonance measurements,
illustrating how rich self-induced spin-torque phenomenology can arise even in
simple magnetic structures.",2103.05743v2
2022-02-08,Precession of entangled spin and pseudospin in double quantum dots,"Quantum dot spin valves are characterized by exchange fields which induce
spin precession and generate current spin resonances even in absence of spin
splitting. Analogous effects have been studied in double quantum dots, in which
the orbital degree of freedom, the pseudospin, replaces the spin in the valve
configuration. We generalize, now, this setup to allow for arbitrary spin and
orbital polarization of the leads, thus obtaining an even richer variety of
current resonances, stemming from the precession dynamics of entangled spin and
pseudospin. We observe for both vectors a delicate interplay of decoherence,
pumping and precession which can only be understood by also considering the
dynamics of the spin-pseudospin correlators. The numerical results are obtained
in the framework of a generalized master equation within the cotunneling
approximation and are complemented by the analytics of a coherent sequential
tunneling model.",2202.04186v1
2022-09-29,Flopping-mode spin qubit in a Si-MOS quantum dot,"Spin qubits based on silicon metal-oxide semiconductor (Si-MOS) quantum dots
(QDs) are promising platforms for large-scale quantum computers. To control
spin qubits in QDs, electric dipole spin resonance (EDSR) has been most
commonly used in recent years. By delocalizing an electron across a double
quantum dots charge state, flopping-mode EDSR has been realized in Si/SiGe QDs.
Here, we demonstrate a flopping-mode spin qubit in a Si-MOS QD via Elzerman
single-shot readout. When changing the detuning with a fixed drive power, we
achieve s-shape spin resonance frequencies, an order of magnitude improvement
in the spin Rabi frequencies, and virtually constant spin dephasing times. Our
results offer a route to large-scale spin qubit systems with higher control
fidelity in Si-MOS QDs.",2209.14531v2
2023-11-06,Resonant tunneling and quantum interference of a two-spin system in silicon tunnel FETs,"We investigated the resonant tunneling of a two-spin system through the
double quantum dots in Al-N-implanted silicon tunnel FETs (TFETs) by
electrical-transport measurements and Landau-Zener-St\""{u}ckelberg-Majorana
interferometry with and without magnetic fields. Our experimental results
revealed the coexistence of spin-conserving and spin-flip tunneling channels in
the two-spin system in non-zero magnetic fields. Additionally, we obtained the
spin-conserving/spin-flip tunneling rates of the two-spin system through the
double quantum dots in the TFET. These findings will improve our understanding
of the two-spin system in silicon TFET qubits and may facilitate the coherent
control of quantum states through all-electric manipulation.",2311.02885v1
2004-11-09,Spin-dependent resonant tunneling through quantum-well states in magnetic metallic thin films,"Quantum-well (QW) states in {\it nonmagnetic} metal layers contained in
magnetic multilayers are known to be important in spin-dependent transport, but
the role of QW states in {\it magnetic} layers remains elusive. Here we
identify the conditions and mechanisms for resonant tunneling through QW states
in magnetic layers and determine candidate structures. We report
first-principles calculations of spin-dependent transport in epitaxial
Fe/MgO/FeO/Fe/Cr and Co/MgO/Fe/Cr tunnel junctions. We demonstrate the
formation of sharp QW states in the Fe layer and show discrete conductance
jumps as the QW states enter the transport window with increasing bias. At
resonance, the current increases by one to two orders of magnitude. The
tunneling magnetoresistance ratio is several times larger than in simple spin
tunnel junctions and is positive (negative) for majority- (minority-) spin
resonances, with a large asymmetry between positive and negative biases. The
results can serve as the basis for novel spintronic devices.",0411233v1
2006-02-28,Photon-assisted electron transmission resonance through a quantum well with spin-orbit coupling,"Using the effective-mass approximation and Floquet theory, we study the
electron transmission over a quantum well in semiconductor heterostructures
with Dresselhaus spin-orbit coupling and an applied oscillation field. It is
demonstrated by the numerical evaluations that Dresselhaus spin-orbit coupling
eliminates the spin degeneracy and leads to the splitting of asymmetric
Fano-type resonance peaks in the conductivity. In turn, the splitting of
Fano-type resonance induces the spin- polarization-dependent electron-current.
The location and line shape of Fano-type resonance can be controlled by
adjusting the oscillation frequency and the amplitude of external field as
well. These interesting features may be a very useful basis for devising
tunable spin filters.",0602658v1
2010-12-22,Rashba field in GaN,"We discuss problem of Rashba field in bulk GaN and in GaN/AlGaN
two-dimensional electron gas, basing on results of X-band microwave resonance
experiments. We point at large difference in spin-orbit coupling between bulk
material and heterostructures. We observe coupled plasmon-cyclotron resonance
from the two-dimensional electron gas, but no spin resonance, being consistent
with large zero-field spin splitting due to the Rashba field reported in
literature. In contrast, small anisotropy of g-factor of GaN effective mass
donors indicates rather weak Rashba spin-orbit coupling in bulk material, not
exceed 400 Gauss, alpha_BIA < 4*10^-13 eVcm. Furthermore, we observe new kind
of electron spin resonance in GaN, which we attribute to surface electron
accumulation layer. We conclude that the sizable Rashba field in GaN/AlGaN
heterostructures originates from properties of the interface.",1012.4999v1
2011-03-13,Micromagnetic understanding of stochastic resonance driven by spin-transfertorque,"In this paper, we employ micromagnetic simulations to study non-adiabatic
stochastic resonance (NASR) excited by spin-transfer torque in a
super-paramagnetic free layer nanomagnet of a nanoscale spin valve. We find
that NASR dynamics involves thermally activated transitions among two static
states and a single dynamic state of the nanomagnet and can be well understood
in the framework of Markov chain rate theory. Our simulations show that a
direct voltage generated by the spin valve at the NASR frequency is at least
one order of magnitude greater than the dc voltage generated off the NASR
frequency. Our computations also reproduce the main experimentally observed
features of NASR such as the resonance frequency, the temperature dependence
and the current bias dependence of the resonance amplitude. We propose a simple
design of a microwave signal detector based on NASR driven by spin transfer
torque.",1103.2536v1
2011-11-26,"Evidence for a negative-parity spin-doublet of nucleon resonances at 1.88\,GeV","Evidence is reported for two nucleon resonances with spin-parity $J^P=1/2^-$
and $J^P=3/2^-$ at a mass just below 1.9\,GeV. The evidence is derived from a
coupled-channel analysis of a large number of pion and photo-produced
reactions. The two resonances are nearly degenerate in mass with two resonances
of the same spin but positive parity. Such parity doublets are predicted in
models claiming restoration of chiral symmetry in high-mass excitations of the
nucleon. Further examples of spin parity doublets are found in addition.
Alternatively, the spin doublet can be interpreted as member of the 56-plet
expected in the third excitation band of the nucleon. Implications for the
problem of the {\it missing resonances} are discussed.",1111.6151v2
2012-04-27,Resonant harmonic generation and collective spin rotations in electrically driven quantum dots,"Spin rotations induced by an AC electric field in a two-electron double
quantum dot are studied by an exact numerical solution of the time dependent
Schroedinger equation in the context of recent electric dipole spin resonance
experiments based on the Pauli blockade. We demonstrate that the splitting of
the main resonance line by the spin exchange coupling is accompanied by the
appearance of fractional resonances and that both these effects are triggered
by interdot tunnel coupling. We find that the AC driven system generates
residual but distinct harmonics of the driving frequency which are amplified
when tuned to the main transition frequency. The mechanism is universal for
electron systems in electrically driven potentials and works also in the
absence of electron-electron interaction or spin-orbit coupling.",1204.6208v2
2012-10-03,Numerical study of spin-dependent transition rates within pairs of dipolar and strongly exchange coupled spins with (s=1/2) during magnetic resonant excitation,"The effect of dipolar and exchange interactions within pairs of paramagnetic
electronic states on Pauli-blockade-controlled spin-dependent transport and
recombination rates during magnetic resonant spin excitation is studied
numerically using the superoperator Liouville-space formalism. The simulations
reveal that spin-Rabi nutation induced by magnetic resonance can control
transition rates which can be observed experimentally by pulsed electrically
(pEDMR) and pulsed optically (pODMR) detected magnetic resonance
spectroscopies. When the dipolar coupling exceeds the difference of the pair
partners' Zeeman energies, several nutation frequency components can be
observed, the most pronounced at sqrt{2} gamma B_1 (gamma is the gyromagnetic
ratio, B_1 is the excitation field). Exchange coupling does not significantly
affect this nutation component; however, it does strongly influence a
low-frequency component < gamma B_1. Thus, pEDMR/pODMR allow the simultaneous
identification of exchange and dipolar interaction strengths.",1210.0950v2
2013-01-21,Modulation effect on the spin Hall resonance,"The effect of a weak electrical modulation on spin Hall resonance is
presented here. In presence of the magnetic field normal to the plane of the
motion of electron, the Landau levels are formed which get broadened due to the
weak modulation. The width of the Landau levels broadening are periodic with
the inverse magnetic field. There is a certain magnetic field for which the
crossing of Landau levels between spin-up and spin-down branches takes place.
This gives rise to the resonance in the spin Hall conductivity (SHC). The
Landau levels broadening or the energy correction due to the modulation removes
the singularity appears at the resonance field in SHC, leading to the
suppression of SHC accompanied by two new peaks around this point. The
separation of these two peaks increases with the increase of the modulation
period. Moreover, we find that the height of the two peaks are also modulation
period dependent.",1301.4841v1
2014-11-22,Quantification of the spin-Hall anti-damping torque with a resonance spectrometer,"We present a simple technique using a cavity-based resonance spectrometer to
quantify the anti-damping torque due to the spin Hall effect. Modification of
ferromagnetic resonance is observed as a function of small DC current in
sub-mm-wide strips of bilayers, consisting of magnetically soft FeGaB and
strong spin-Hall metal Ta. From the detected current-induced linewidth change,
we obtain an effective spin Hall angle of 0.08-0.09 independent of the magnetic
layer thickness. Our results demonstrate that a sensitive resonance
spectrometer can be a general tool to investigate spin Hall effects in various
material systems, even those with vanishingly low conductivity and
magnetoresistance.",1411.6166v1
2015-03-20,YBCO microwave resonators for strong collective coupling with spin ensembles,"Coplanar microwave resonators made of 330 nm-thick superconducting YBCO have
been realized and characterized in a wide temperature ($T$, 2-100 K) and
magnetic field ($B$, 0-7 T) range. The quality factor $Q_L$ exceeds 10$^4$
below 55 K and it slightly decreases for increasing fields, remaining 90$\%$ of
$Q_L(B=0)$ for $B=7$ T and $T=2$ K. These features allow the coherent coupling
of resonant photons with a spin ensemble at finite temperature and magnetic
field. To demonstrate this, collective strong coupling was achieved by using
DPPH organic radical placed at the magnetic antinode of the fundamental mode:
the in-plane magnetic field is used to tune the spin frequency gap splitting
across the single-mode cavity resonance at 7.75 GHz, where clear anticrossings
are observed with a splitting as large as $\sim 82$ MHz at $T=2$ K. The
spin-cavity collective coupling rate is shown to scale as the square root of
the number of active spins in the ensemble.",1503.06145v2
2016-08-03,Impurity-induced smearing of the spin resonance peak in Fe-based superconductors,"The spin resonance peak in the iron-based superconductors is observed in
inelastic neutron scattering experiments and agrees well with predicted results
for the extended s-wave ($s_\pm$) gap symmetry. On the basis of four-band and
three-orbital tight binding models we study the effect of nonmagnetic disorder
on the resonance peak. Spin susceptibility is calculated in the random phase
approximation with the renormalization of the quasiparticle self-energy due to
the impurity scattering in the static Born approximation. We find that the spin
resonance becomes broader with the increase of disorder and its energy shifts
to higher frequencies. For the same amount of disorder the spin response in the
$s_\pm$ state is still distinct from that of the $s_{++}$ state.",1608.01157v1
2017-08-29,Antiferromagnetic resonance excited by oscillating electric currents,"In antiferromagnetic materials the order parameter exhibits resonant modes at
frequencies that can be in the terahertz range, making them interesting
components for spintronic devices. Here, it is shown that antiferromagnetic
resonance can be excited using the inverse spin-Hall effect in a system
consisting of an antiferromagnetic insulator coupled to a normal-metal
waveguide. The time-dependent interplay between spin-torque, ac
spin-accumulation and magnetic degrees of freedom is studied. It is found that
the dynamics of the antiferromagnet effects the frequency-dependent
conductivity of the normal metal. Further, it is shown that in
antiferromagnetic insulators, the resonant excitation by ac spin-currents can
be orders of magnitude more efficient than excitation by the current-induced
Oersted field.",1708.08965v2
2017-12-08,A Novel Effect of Electron Spin Resonance on Electrical Resistivity,"We extend the well known phenomenon of magnetoresistance (extra resistivity
of materials in transverse magnetic field) to a new and unexplored regime where
in addition to a transverse magnetic field, a transverse AC field of resonant
frequency is also applied. In a magnetic field, electron spin levels are Zeeman
split. In a resonant AC field, we uncover a new channel of momentum relaxation
in which electrons in upper Zeeman level can deexcite to lower Zeeman level by
generating spin fluctuation excitation in the lattice (similar to what happens
in Electron Spin Resonance (ESR) spectroscopy). An additional resistivity due
to this novel mechanism is predicted in which momentum randomization of Zeeman
split electrons happen via bosonic excitations (spin fluctuations). An order of
magnitude of this additional resistivity is calculated. The whole work is based
upon an extension of Einstein's derivation of equilibrium Planckian formula to
near equilibrium systems.",1712.03062v1
2017-12-08,Spin polarization through Floquet resonances in a driven central spin model,"Adiabatically varying the driving frequency of a periodically-driven
many-body quantum system can induce controlled transitions between resonant
eigenstates of the time-averaged Hamiltonian, corresponding to adiabatic
transitions in the Floquet spectrum and presenting a general tool in quantum
many-body control. Using the central spin model as an application, we show how
such controlled driving processes can lead to a polarization-based decoupling
of the central spin from its decoherence-inducing environment at resonance.
While it is generally impossible to obtain the exact Floquet Hamiltonian in
driven interacting systems, we exploit the integrability of the central spin
model to show how techniques from quantum quenches can be used to explicitly
construct the Floquet Hamiltonian in a restricted many-body basis and model
Floquet resonances.",1712.03117v2
2018-06-21,Spin transfer torque induced paramagnetic resonance,"We show how the spin-transfer torque generated by an ac voltage may be used
to excite a paramagnetic resonance of an atomic spin deposited on a metallic
surface. This mechanism is independent of the environment of the atom and may
explain the ubiquity of the paramagnetic resonance reported by Baumann
$\textit{et al.}$ [$\href{http://dx.doi.org/10.1126/science.aac8703}{Science
\textbf{350}, 417 (2015)}$]. The current and spin dynamics are modeled by a
time-dependent Redfield master equation generalized to account for the periodic
driven voltage. Our approach shows that the resonance effect is a consequence
of the nonlinearity of the coupling between the magnetic moment and the
spin-polarized current which generates a large second-harmonic amplitude that
can be measured in the current signal.",1806.08260v2
2017-06-13,Mesoscopic magnetic resonance spectroscopy with a remote spin sensor,"Quantum sensing based on nitrogen-vacancy (NV) centers in diamond has been
developed as a powerful tool for microscopic magnetic resonance. However, the
reported sensor-to-sample distance is limited within tens of nanometers because
the signal of spin fluctuation decreases cubically with the increasing
distance. Here we extend the sensing distance to tens of micrometers by
detecting spin polarization rather than spin fluctuation. We detected the
mesoscopic magnetic resonance spectra of polarized electrons of a
pentacene-doped crystal, measured its two typical decay times and observed the
optically enhanced spin polarization. This work paves the way for the NV-based
mesoscopic magnetic resonance spectroscopy and imaging at ambient conditions.",1706.03939v2
2017-10-28,Sensitive spin detection using an on-chip SQUID-waveguide resonator,"Precise detection of spin resonance is of paramount importance to achieve
coherent spin control in quantum computing. We present a novel setup for spin
resonance measurements, which uses a dc-SQUID flux detector coupled to an
antenna from a coplanar waveguide. The SQUID and the waveguide are fabricated
from 20~nm Nb thin film, allowing high magnetic field operation with the field
applied parallel to the chip. We observe a resonance signal between the first
and third excited states of Gd spins $S=7/2$ in a CaWO$_4$ crystal, relevant
for state control in multi-level systems.",1710.10506v1
2020-03-10,Spin detection via parametric frequency conversion in a membrane resonator,"Recent demonstrations of ultracoherent nanomechanical resonators introduce
the prospect of new protocols for solid state sensing applications. Here, we
propose to use two coupled ultracoherent resonator modes on a Si$_3$N$_4$
membrane for the detection of small nuclear spin ensembles. To this end, we
employ parametric frequency conversion between nondegenerate modes. The
nondegenerate modes result from coupled degenerate resonators, and the
parametric conversion is mediated by periodic inversions of the nuclear spins
in the presence of a magnetic scanning tip. We analyze potential noise sources
and derive the achievable signal-to-noise ratio with typical experimental
parameter values. Our proposal reconciles the geometric constraints of
optomechanical systems with the requirements of scanning force microscopy and
brings forth a new platform for spin-phonon interaction and spin imaging.",2003.04557v2
2019-08-15,Excitation of Tumbling in Phobos and Deimos,"Mass-spring model simulations are used to investigate past spin states of a
viscoelastic Phobos and Deimos. From an initially tidally locked state, we find
crossing of a spin-orbit resonance with Mars or a mean motion resonance with
each other does not excite tumbling in Phobos or Deimos. However, once tumbling
our simulations show that these moons can remain so for an extended period and
during this time their orbital eccentricity can be substantially reduced. We
attribute the tendency for simulations of an initially tumbling viscoelastic
body to drop into spin-synchronous state at very low eccentricity to the
insensitivity of the tumbling chaotic zone volume to eccentricity. After a
tumbling body enters the spin synchronous resonance, it can exhibit long lived
non-principal axis rotation and this too can prolong the period of time with
enhanced tidally generated energy dissipation. The low orbital eccentricities
of Phobos and Deimos could in part be due to spin excitation by nearly
catastrophic impacts rather than tidal evolution following orbital resonance
excitation.",1908.05720v2
2019-10-10,Slow Nonthermalizing Dynamics in a Quantum Spin Glass,"Spin glasses and many-body localization (MBL) are prime examples of
ergodicity breaking, yet their physical origin is quite different: the former
phase arises due to rugged classical energy landscape, while the latter is a
quantum-interference effect. Here we study quantum dynamics of an isolated 1d
spin-glass under application of a transverse field. At high energy densities,
the system is ergodic, relaxing via resonance avalanche mechanism, that is also
responsible for the destruction of MBL in non-glassy systems with power-law
interactions. At low energy densities, the interaction-induced fields obtain a
power-law soft gap, making the resonance avalanche mechanism inefficient. This
leads to the persistence of the spin-glass order, as demonstrated by resonance
analysis and by numerical studies. A small fraction of resonant spins forms a
thermalizing system with long-range entanglement, making this regime distinct
from the conventional MBL. The model considered can be realized in systems of
trapped ions, opening the door to investigating slow quantum dynamics induced
by glassiness.",1910.04421v2
2023-04-03,Magnetic resonance in the quasi-2D square lattice easy-plane antiferromagnet Ba$_2$MnGe$_2$O$_7$,"We report results of a multi-frequency (0.8-60 GHz) electron spin resonance
study of the spin dynamics in the quasi-2D square lattice antiferromagnet
Ba$_2$MnGe$_2$O$_7$ both in antiferromagnetically ordered and paramagnetic
phases. We directly observe two zero-field gaps in the excitation spectrum of
the ordered phase, the larger one being due to easy-plane anisotropy, and the
smaller one indicates the presence of fourth-order in-plane anisotropy probably
related to the multiferroic properties of this compound. We observe effects of
hyperfine interaction on the electron spin resonance spectra in the
antiferromagnetically ordered state, which turns out to be comparable with
in-plane anisotropy. The hyperfine field strength is found from the observed
low-temperature electron spin resonance data. The spin dynamics of the
paramagnetic phase is characterized by strong broadening of the ESR absorption
line, which can be ascribed to the vortex dynamics of a 2D magnet.",2304.01280v1
2023-06-05,Normal single-spin asymmetries in electron-proton scattering: two-photon exchange with intermediate state resonances,"We calculate the beam ($B_n$) and target ($A_n$) normal single-spin
asymmetries in electron-proton elastic scattering from two-photon exchange
amplitudes with resonance intermediate states of spin-parity $1/2^\pm$ and
$3/2^\pm$ and mass $W \lesssim 1.8$ GeV. The latest CLAS exclusive meson
electroproduction data are used as input for the transition amplitudes from the
proton to the excited resonance states. For $B_n$, the spin 3/2 resonances
dominate by an order of magnitude over the spin 1/2 states. In general we
observe cancellations between the negative contributions of the $\Delta(1232)$
and $N(1520)$ across both beam energy and scattering angle, and the positive
contributions of the $\Delta(1700)$ and $N(1720)$, leading to a rather large
overall uncertainty band in the total $B_n$. At forward angles and beam
energies $E_\textrm{lab}<1$ GeV, where the $\Delta(1232)$ dominates, the
calculated $B_n$ tend to overshoot the A4 and SAMPLE data. The calculated $B_n$
compare well with the measured values from the A4 and $Q_{\textrm{weak}}$
experiments with $E_\textrm{lab}>1$ GeV.",2306.02540v1
2024-02-28,Coherent control of terahertz-scale spin resonances using optical spin-orbit torques,"Using optically generated spin-orbit torques generated by the heavy metal Pt
we demonstrate coherent control of GHz ferromagnetic resonances in Pt/Co/Pt
multilayers as well as sub-THz exchange resonances in [Gd/Co]$_2$ multilayers.
Employing a double-pump setup, we show that depending on the helicities of the
pump pulses, spin resonances can either be coherently amplified or suppressed
if the time delay between the arrival of the pump beams is chosen
appropriately. Furthermore, investigating phase and amplitude of the
exchange-driven modes, we identify features that challenge the current
understanding of optically generated spin-orbit torques, and we discuss
possible explanations.",2402.18671v1
2011-04-10,Spatial Damping of Propagating Kink Waves Due to Resonant Absorption: Effect of Background Flow,"Observations show the ubiquitous presence of propagating magnetohydrodynamic
(MHD) kink waves in the solar atmosphere. Waves and flows are often observed
simultaneously. Due to plasma inhomogeneity in the perpendicular direction to
the magnetic field, kink waves are spatially damped by resonant absorption. The
presence of flow may affect the wave spatial damping. Here, we investigate the
effect of longitudinal background flow on the propagation and spatial damping
of resonant kink waves in transversely nonuniform magnetic flux tubes. We
combine approximate analytical theory with numerical investigation. The
analytical theory uses the thin tube (TT) and thin boundary (TB) approximations
to obtain expressions for the wavelength and the damping length. Numerically,
we verify the previously obtained analytical expressions by means of the full
solution of the resistive MHD eigenvalue problem beyond the TT and TB
approximations. We find that the backward and forward propagating waves have
different wavelengths and are damped on length scales that are inversely
proportional to the frequency as in the static case. However, the factor of
proportionality depends on the characteristics of the flow, so that the damping
length differs from its static analogue. For slow, sub-Alfvenic flows the
backward propagating wave gets damped on a shorter length scale than in the
absence of flow, while for the forward propagating wave the damping length is
longer. The different properties of the waves depending on their direction of
propagation with respect to the background flow may be detected by the
observations and may be relevant for seismological applications.",1104.1791v1
2013-04-12,Kronoseismology: Using density waves in Saturn's C ring to probe the planet's interior,"Saturn's C ring contains multiple spiral patterns that appear to be density
waves driven by periodic gravitational perturbations. In other parts of
Saturn's rings, such waves are generated by Lindblad resonances with Saturn's
various moons, but most of the wave-like C-ring features are not situated near
any strong resonance with any known moon. Using stellar occultation data
obtained by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the
Cassini spacecraft, we investigate the origin of six unidentified C-ring waves
located between 80,900 and 87,200 km from Saturn's center. By measuring
differences in the waves' phases among the different occultations, we are able
to determine both the number of arms in each spiral pattern and the speeds at
which these patterns rotate around the planet. We find that all six of these
waves have between 2 and 4 arms and pattern speeds between 1660 degrees/day and
1861 degrees/day. These speeds are too large to be attributed to any satellite
resonance. Instead they are comparable to the predicted pattern speeds of waves
generated by low-order normal-mode oscillations within the planet [Marley &
Porco 1993, Icarus 106, 508]. The precise pattern speeds associated with these
waves should therefore provide strong constraints on Saturn's internal
structure. Furthermore, we identify multiple waves with the same number of arms
and very similar pattern speeds, indicating that multiple m=3 and m=2 sectoral
(l=m) modes may exist within the planet.",1304.3735v2
2021-07-16,Three-dimensionality of the triadic resonance instability of a plane inertial wave,"We analyze theoretically and experimentally the triadic resonance instability
(TRI) of a plane inertial wave in a rotating fluid. Building on the classical
triadic interaction equations between helical modes, we show by numerical
integration that the maximum growth rate of the TRI is found for secondary
waves that do not propagate in the same vertical plane as the primary wave (the
rotation axis is parallel to the vertical). In the inviscid limit, we prove
this result analytically, in which case the change in the horizontal
propagation direction induced by the TRI evolves from $60^\circ$ to $90^\circ$
depending on the frequency of the primary wave. Thanks to a wave generator with
a large spatial extension in the horizontal direction of invariance of the
forced wave, we are able to report experimental evidence that the TRI of a
plane inertial wave is three-dimensional. The wavevectors of the secondary
waves produced by the TRI are shown to match the theoretical predictions based
on the maximum growth rate criterion. These results reveal that the triadic
resonant interactions between inertial waves are very efficient at
redistributing energy in the horizontal plane, normal to the rotation axis.",2107.07937v1
2017-11-30,Oblique propagation of longitudinal spin-electron acoustic waves under the influence of the Coulomb exchange interaction and the quantum Bohm potential,"Influence of the exchange interaction on the properties of the spin-electron
acoustic waves at the oblique propagation of waves relatively to the external
magnetic field in the magnetically ordered metals is studied. The spectra of
the Langmuir wave and the Trivelpiece-Gould wave are also considered. It is
well-known that there are two branches of spectrum of the spin-electron
acoustic waves in this regime. Change their properties under influence of the
exchange interaction is studied. The quantum Bohm potential is included either.
The exchange interaction and quantum Bohm potential gives opposite
contributions, but they do not compensate each other since they have different
dependence on the wave vector. This competition creates a non-monotonical
behavior of the Trivelpiece-Gould wave spectrum. The concavity changes in the
monotonic spectra of the Langmuir wave and the SEAWs are found.",1711.11308v1
2003-11-10,Long-Lived Spin Coherence States,"We study evolution of electron spin coherence having non-homogeneous
direction of spin polarization vector in semiconductor heterostructures. It is
found that the electron spin relaxation time due to the D'yakonov-Perel'
relaxation mechanism essentially depends on the initial spin polarization
distribution. This effect has its origin in the coherent spin precession of
electrons diffusing in the same direction. We predict a long spin relaxation
time of a novel structure: a spin coherence standing wave and discuss its
experimental realization.",0311223v1
2004-10-20,Spin-Transfer Torque and Electron-Magnon Scattering,"According to the spin-torque model, current-driven magnetic dynamics in
ferromagnetic multilayers is determined by the transfer of electron spin
perpendicular to the layers' magnetizations. By separating the largest
contributions to the magnetic dynamics, we demonstrate that the dominant effect
of spin-torque is rather due to the electron spin parallel to the field. We
show that this effect can be equivalently described as stimulated
current-driven excitation of spin-waves, and discuss four specifically
quantum-mechanical aspects of spin-transfer, not described by the spin-torque.",0410520v1
2007-01-09,Spin Supercurrent,"We review the main properties of Spin Waves condensation to a coherent
quantum state, named Homogeneously Precessing Domain (HPD). We describe the
long range coherent transport of magnetization by Spin Supercurrent in
antiferromagnetic superfluid 3He. This quantum phenomenon was discovered 20
years ago. Since then, many magnetic extensions of superconductivity and
superfluidity have been observed: spin Josephson phenomena, spin current
vortices, spin phase slippage, long distance magnetization transport by spin
supercurrents, etc. Several new supercurrent phenomena have been discovered,
like magnetically excited coherent quantum states, NMR in the molecular Landau
field, spin-current turbulence, formation of stable non-topological solitons
etc.",0701182v1
2007-09-13,Spin polarization in biased Rashba-Dresselhaus two-dimensional electron systems,"Based on spin-charge coupled drift-diffusion equations, which are derived
from kinetic equations for the spin-density matrix in a rigorous manner, the
electric-field-induced nonequilibrium spin polarization is treated for a
two-dimensional electron gas with both Rashba and Dresselhaus spin-orbit
coupling. Most emphasis is put on the consideration of the field-mediated spin
dynamics for a model with equal Rashba and Dresselhaus coupling constants, in
which the spin relaxation is strongly suppressed. Weakly damped
electric-field-induced spin excitations are identified, which remind of
space-charge waves in crystals.",0709.2054v1
2008-08-01,Electric-field driven long-lived spin excitations on a cylindrical surface with spin-orbit interaction,"Based on quantum-kinetic equations, coupled spin-charge drift-diffusion
equations are derived for a two-dimensional electron gas on a cylindrical
surface. Besides the Rashba and Dresselhaus spin-orbit interaction, the elastic
scattering on impurities, and a constant electric field are taken into account.
  From the solution of the drift-diffusion equations, a long-lived spin
excitation is identified for spins coupled to the Rashba term on a cylinder
with a given radius. The electric-field driven weakly damped spin waves are
manifest in the components of the magnetization and have the potential for
non-ballistic spin-device applications.",0808.0069v1
2013-05-09,Spin Conductivity in Two-Dimensional Non-Collinear Antiferromagnets,"We propose a method to derive the spin current operator for non-collinear
Heisenberg antiferromagnets. We show that the spin conductivity calculated by
the spectral representation with the spin current satisfies the f-sum rule. We
also study the spin conductivity at T=0 within spin wave theory. We show how
the spin conductivity depends on the external magnetic field with changing
magnon spectrum. We also find that the spin Drude weight vanishes for any
external magnetic field at T=0.",1305.2072v3
2015-04-30,Spin electron acoustic soliton: Separate spin evolution of electrons with exchange interaction,"Separate spin evolution quantum hydrodynamics is generalized to include the
Coulomb exchange interaction. The Coulomb exchange interaction is considered as
the interaction between the spin-down electrons being in the quantum states
occupied by one electron, giving main contribution in the equilibrium. The
generalized model is applied to study the non-linear spin-electron acoustic
waves. Existence of the spin-electron acoustic soliton is demonstrated.
Contributions of the concentration, spin polarization, and exchange interaction
in the properties of the spin electron acoustic soliton are studied.",1504.08234v2
2012-05-06,Free-Electron Laser-Powered Electron Paramagnetic Resonance Spectroscopy,"Electron paramagnetic resonance (EPR) spectroscopy interrogates unpaired
electron spins in solids and liquids to reveal local structure and dynamics;
for example, EPR has elucidated parts of the structure of protein complexes
that have resisted all other techniques in structural biology. EPR can also
probe the interplay of light and electricity in organic solar cells and
light-emitting diodes, and the origin of decoherence in condensed matter, which
is of fundamental importance to the development of quantum information
processors. Like nuclear magnetic resonance (NMR), EPR spectroscopy becomes
more powerful at high magnetic fields and frequencies, and with excitation by
coherent pulses rather than continuous waves. However, the difficulty of
generating sequences of powerful pulses at frequencies above 100 GHz has, until
now, confined high-power pulsed EPR to magnetic fields of 3.5 T and below. Here
we demonstrate that ~1 kW pulses from a free-electron laser (FEL) can power a
pulsed EPR spectrometer at 240 GHz (8.5 T), providing transformative
enhancements over the alternative, a state-of-the-art ~30 mW solid state
source. Using the UC Santa Barbara FEL as a source, our 240 GHz spectrometer
can rotate spin-1/2 electrons through pi/2 in only 6 ns (vs. 300 ns with the
solid state source). Fourier transform EPR on nitrogen impurities in diamond
demonstrates excitation and detection of EPR lines separated by ~200 MHz.
Decoherence times for spin-1/2 systems as short as 63 ns are measured, enabling
measurement of the decoherence time in a frozen solution of nitroxide
free-radicals at temperatures as high as 190 K. Both FELs and the quasi-optical
technology developed for the spectrometer are scalable to frequencies well in
excess of 1 THz, opening the possibility of high-power pulsed EPR spectroscopy
up to the highest static magnetic fields on earth.",1205.1186v1
2012-07-11,Well-established nucleon resonances revisited by double-polarization measurements,"The first measurement is reported of the double-polarization observable G in
photoproduction of neutral pions off protons, covering the photon energy range
from 620 to 1120 MeV and the full solid angle. G describes the correlation
between the photon polarization plane and the scattering plane for protons
polarized along the direction of the incoming photon. The observable is highly
sensitive to contributions from baryon resonances. The new results are compared
to the predictions from SAID, MAID, and BnGa partial wave analyses. In spite of
the long-lasting efforts to understand {\gamma}p -> p{\pi} 0 as the simplest
photoproduction reaction, surprisingly large differences between the new data
and the latest predictions are observed which are traced to different
contributions of the N (1535) with spin-parity J^P = 1/2^- and N (1520) with
J^P = 3/2^- . In the third resonance region, where N (1680) with J^P = 5/2^+
production dominates, the new data are reasonably close to the predictions.",1207.2686v2
2013-08-28,Second harmonic generation spectroscopy of excitons in ZnO,"Nonlinear optics of semiconductors is an important field of fundamental and
applied research, but surprisingly the role of excitons in the coherent
processes leading to harmonics generation has remained essentially unexplored.
Here we report results of a comprehensive experimental and theoretical study of
the three-photon process of optical second harmonic generation (SHG) involving
the exciton resonances of the noncentrosymmetric hexagonal wide-band-gap
semiconductor ZnO in the photon energy range of 3.2-3.5 eV. Resonant
crystallographic SHG is observed for the 1s(A,B), 2s(A,B), 2p(A,B), and 1s(C)
excitons. We show that strong SHG signals at these exciton resonances are
induced by the application of a magnetic field when the incident and the SHG
light wave vectors are along the crystal z-axis where the crystallographic SHG
response vanishes. A microscopic theory of SHG generation through excitons is
developed, which shows that the nonlinear interaction of coherent light with
excitons has to be considered beyond the electric-dipole approximation.
Depending on the particular symmetry of the exciton states SHG can originate
from the electric- and magnetic-field-induced perturbations of the excitons due
to the Stark effect, the spin as well as orbital Zeeman effects, or the
magneto-Stark effect. The importance of each mechanism is analyzed and
discussed by confronting experimental data and theoretical results for the
dependencies of the SHG signals on photon energy, magnetic field, electric
field, crystal temperature, and light polarization. Good agreement is obtained
between experiment and theory proving the validity of our approach to the
complex problem of nonlinear interaction of light with ZnO excitons. This
general approach can be applied also to other semiconductors.",1308.6219v1
2015-09-21,Kondo induced π-phase shift of microwave photons in a circuit quantum electrodynamics architecture,"Mesoscopic systems constitute appealing platforms to study many-body physics
with light and matter degrees of freedom. The Kondo effect refers to the
screening of a spin-1/2 impurity by a cloud of conduction electrons, then
forming a many-body Fermi liquid ground state. The Kondo resonance produces a
phase shift in the transmitted electronic wave packet which depends on the
symmetry and nature of the many-body ground state. Theoretical calculations
suggest that the Kondo resonance can interact with the irradiation photon field
and should give rise to a {\pi}-phase shift of the photon signal in the case
where the ground state is a Fermi liquid. This {\pi}-phase shift of microwave
photon is driven from the Korringa-Shiba relation of quantum impurity
Fermi-liquid ground states. We report the first observation of such a
{\pi}-phase shift in a graphene double quantum dot within a circuit quantum
electrodynamics architecture where the microwave photons couple to the
pseudo-spin or charge degrees of freedom. The observed Kondo temperature TK ~
550 mK is in agreement with DC conductance measurements. All our results
support the formation of a Kondo resonance located above the Fermi level of the
electronic reservoirs and the occurrence of an SU(4) Fermi-liquid ground state.
We finally study how the Kondo-photon interactions can be tuned by inter-dot
electron tunnel coupling strengths. Our experimental achievements may
contribute to a better understanding of many-body physics in hybrid circuit
systems, and open up new applications in atomic thin materials from the
light-matter interaction.",1509.06141v3
2016-08-17,Modelling duality between bound and resonant meson spectra by means of free quantum motions on the de Sitter space time dS4,"We seek for a pair of a well and barrier potentials such that the real parts
of the complex energies of the resonances transmitted through the barrier equal
the energies of the states bound within the well and find the hyperbolic
Poeschl-Teller barrier, ~sech^2\rho, and the trigonometric Scarf well, ~
\sec^2\chi. The potentials are shown to be conformally symmetric by the aid of
the de Sitter space time, dS4, related to flat conformal space time by a
conformal map. Namely, we transform the quantum mechanical wave equations with
the above potentials to free quantum motions on the respective open time like
hyperbolic and the closed space like hyper spherical, S3, geodesics of dS4, the
former by itself is related to Minkowski space time by a conformal map.We
formulate a conformal symmetry respecting classification scheme for mesons seen
either as resonances in scattering, or as states bound within a potential,
according to trajectories in which the total spin of the meson, l-depends
linearly on the first power of the invariant mass, M, and not as in the
canonical Regge formalism on the squared mass.We analyze 71 reported mesons in
this scheme and in finding good agreement with data predict the masses of 12
missing mesons. We observe that on S3 the color quantum number of mesons is
limited to neutral. To the amount physics is independent of the choice of the
set of coordinates, this property remains valid in the flat geometry too. We
conclude on the usefulness of conformal maps of flat to curved space times as
tools for modelling and interpreting the color neutrality of hadrons required
by the confinement phenomenon and on the relevance of trigonometric and
hyperbolic potentials for constituent quark models. Finally, all involved
potentials have been motivated by Wilson loops with cusps.",1608.05041v2
2018-05-23,Non-strange Dibaryon Resonances Observed in the $γd\to π^0π^0 d$ Reaction,"Coherent double neutral-pion photoproduction on the deuteron,
$\gamma{d}${$\to$}$\pi^0\pi^0{d}$, has been experimentally studied at incident
photon energies ranging from 0.75 to 1.15 GeV. The total cross section as a
function of the $\gamma{d}$ center-of-mass energy shows resonance-like
behavior, which peaks at approximately 2.47 and 2.63 GeV. The measured angular
distribution of deuteron emission is rather flat, which cannot be reproduced by
the kinematics of quasi-free $\pi^0\pi^0$ production with deuteron coalescence.
In $\pi^0d $ invariant-mass distributions, a clear peak is observed at
$2.14{\pm}0.01$ GeV$/c^2$ with a width of $0.09{\pm}0.01$ GeV$/c^2$. The
spin-parity of this state is restricted to $1^+$, $2^+$ or $3^-$ from the
angular distributions of the two $\pi^0$s. The present work shows strong
evidence for the existence of an isovector dibaryon resonance with a mass of
2.14 GeV$/c^2$. The $2^+$ assignment is consistent with the theoretically
predicted ${\cal{D}}_{12}$ state, and also with the energy dependence of the
$\pi{d}$ partial-wave amplitude $^3\!P_2$ for the
$\pi^{\pm}d${$\to$}$\pi^{\pm}d$ and $\pi^+d${$\to$}${pp}$ reactions.",1805.08928v2
2020-06-05,Time-resolved resonant elastic soft X-ray scattering at Pohang Accelerator Laboratory X-ray Free Electron Laser,"Resonant elastic X-ray scattering has been widely employed for exploring
complex electronic ordering phenomena, like charge, spin, and orbital order, in
particular in strongly correlated electronic systems. In addition, recent
developments of pump-probe X-ray scattering allow us to expand the
investigation of the temporal dynamics of such orders. Here, we introduce a new
time-resolved Resonant Soft X-ray Scattering (tr-RSXS) endstation developed at
the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). This
endstation has an optical laser (wavelength of 800 nm plus harmonics) as the
pump source. Based on the commissioning results, the tr-RSXS at PAL-XFEL can
deliver a soft X-ray probe (400-1300 eV) with a time resolution about ~100 fs
without jitter correction. As an example, the temporal dynamics of a charge
density wave on a high-temperature cuprate superconductor is demonstrated.",2006.03273v2
2022-07-05,Polarization observables in double neutral pion photoproduction,"Measurements of target asymmetries and double-polarization observables for
the reaction $\gamma p\to p\pi^0\pi^0$ are reported. The data were taken with
the CBELSA/TAPS experiment at the ELSA facility (Bonn University) using the
Bonn frozen-spin butanol (C$_4$H$_9$OH) target, which provided transversely
polarized protons. Linearly polarized photons were produced via bremsstrahlung
off a diamond crystal. The data cover the photon energy range from
$E_{\gamma}$=650 MeV to $E_{\gamma}$=2600 MeV and nearly the complete angular
range. The results have been included in the BnGa partial wave analysis.
Experimental results and the fit agree very well. Observed systematic
differences in the branching ratios for decays of $N^*$ and $\Delta^*$
resonances are attributed to the internal structure of these excited nucleon
states. Resonances which can be assigned to SU(6)$\times$O(3) two-oscillator
configurations show larger branching ratios to intermediate states with
non-zero intrinsic orbital angular momenta than resonances assigned to
one-oscillator configurations.",2207.01981v1
2017-12-26,Optimal Orientations of Quartz Crystals for Bulk Acoustic Wave Resonators with the Consideration of Thermal Properties,"Piezoelectric crystals are widely used for acoustic wave resonators of
different functioning modes and types including BAW and SAW. It is well-known
that only some special orientations of crystals will exhibit desirable
properties such as mode couplings, thermal sensitivity, acceleration
sensitivity, and others that are important in design and applications of
resonators. With extensive studies on physical properties in last decades and
increasing industrial needs of novel products, it is necessary to comb the
known knowledge of quartz crystal material for novel orientations and better
products as agendas in the industry. With known material properties like
elastic, piezoelectric, dielectric, and thermal constants, we can establish the
relationships between vibrations and bias fields such as temperature to ensure
a resonator immunizing from excessive response to changes causing significant
degradation of resonator properties and performances. Since the theoretical
framework of wave propagation in piezoelectric solids is known, we need to use
the existing data and results for the validation of current orientations in
actual products. The agreement will give us needed confidence of the theory and
analytical procedures. Through rotations, we calculated physical properties as
functions of angles and bias fields, enabling the calculation of resonator
properties for the identification of optimal cuts. Such a procedure can also be
applied to similar crystals for a careful examination of possible orientations
to maximize the potential use of materials in acoustic wave resonators.",1712.09187v1
2024-02-09,Thermal oscillations and resonance in electron-phonon interaction process,"Thermal resonance, in which the temperature amplitude attains a maximum value
(peak) in response to an external exciting frequency source, is a phenomenon
pertinent to the presence of underdamped thermal oscillations and explicit
finite-speed for the thermal wave propagation. The present work investigates
the occurrence condition for thermal resonance phenomenon during the
electron-phonon interaction process in metals based on the hyperbolic
two-temperature model. First, a sufficient condition for underdamped electron
and lattice temperature oscillations is discussed by deriving a critical
frequency (a material characteristic). It is shown that the critical frequency
of thermal waves near room temperature, during electron-phonon interactions,
may be on the order of terahertz ($10-20$ THz for Cu and Au, i.e., lying within
the terahertz gap). It is found that whenever the natural frequency of metal
temperature exceeds this frequency threshold, the temperature oscillations are
of underdamped type. However, this condition is not necessary, since there is a
small frequency domain, below this threshold, in which the underdamped thermal
wave solution is available but not effective. Otherwise, the critical damping
and the overdamping conditions of the temperature waves are determined
numerically for a sample of pure metals. The thermal resonance conditions in
both electron and lattice temperatures are investigated. The occurrence of
resonance in both electron and lattice temperature is conditional on violating
two distinct critical values of frequencies. When the natural frequency of the
system becomes larger than these two critical values, an applied frequency
equal to such a natural frequency can drive both electron and lattice
temperatures to resonate together with different amplitudes and behaviors.
However, the electron temperature resonates earlier than the lattice
temperature.",2403.09684v1
2012-10-03,Nuclear structure of 30S and its implications for nucleosynthesis in classical novae,"The uncertainty in the 29P(p,gamma)30S reaction rate over the temperature
range of 0.1 - 1.3 GK was previously determined to span ~4 orders of magnitude
due to the uncertain location of two previously unobserved 3+ and 2+ resonances
in the 4.7 - 4.8 MeV excitation region in 30S. Therefore, the abundances of
silicon isotopes synthesized in novae, which are relevant for the
identification of presolar grains of putative nova origin, were uncertain by a
factor of 3. To investigate the level structure of 30S above the proton
threshold (4394.9(7) keV), a charged-particle spectroscopy and an in-beam
gamma-ray spectroscopy experiments were performed. Differential cross sections
of the 32S(p,t)30S reaction were measured at 34.5 MeV. Distorted wave Born
approximation calculations were performed to constrain the spin-parity
assignments of the observed levels. An energy level scheme was deduced from
gamma-gamma coincidence measurements using the 28Si(3He,n-gamma)30S reaction.
Spin-parity assignments based on measurements of gamma-ray angular
distributions and gamma-gamma directional correlation from oriented nuclei were
made for most of the observed levels of 30S. As a result, the resonance
energies corresponding to the excited states in 4.5 MeV - 6 MeV region,
including the two astrophysically important states predicted previously, are
measured with significantly better precision than before. The uncertainty in
the rate of the 29P(p,gamma)30S reaction is substantially reduced over the
temperature range of interest. Finally, the influence of this rate on the
abundance ratios of silicon isotopes synthesized in novae are obtained via 1D
hydrodynamic nova simulations.",1210.1194v1
2018-07-04,Phase Boundary Exchange Coupling in the Mixed Magnetic Phase Regime of a Pd-doped FeRh Epilayer,"Spin-wave resonance measurements were performed in the mixed magnetic phase
regime of a Pd-doped FeRh epilayer that appears as the first-order
ferromagnetic-antiferromagnetic phase transition takes place. It is seen that
the measured value of the exchange stiffness is suppressed throughout the
measurement range when compared to the expected value of the fully
ferromagnetic regime, extracted via the independent means of a measurement of
the Curie point, for only slight changes in the ferromagnetic volume fraction.
This behavior is attributed to the influence of the antiferromagnetic phase:
inspired by previous experiments that show ferromagnetism to be most persistent
at the surfaces and interfaces of FeRh thin films, we modelled the
antiferromagnetic phase as forming a thin layer in the middle of the epilayer
through which the two ferromagnetic layers are coupled up to a certain critical
thickness. The development of this exchange stiffness is then consistent with
that expected from the development of an exchange coupling across the magnetic
phase boundary, as a consequence of a thickness dependent phase transition
taking place in the antiferromagnetic regions and is supported by complimentary
computer simulations of atomistic spin-dynamics. The development of the Gilbert
damping parameter extracted from the ferromagnetic resonance investigations is
consistent with this picture.",1807.01615v6
2017-01-07,High resolution two-dimensional optical spectroscopy of electron spins,"Multidimensional coherent optical spectroscopy is one of the most powerful
tools for investigating complex quantum mechanical systems. While it was
conceived decades ago in magnetic resonance spectroscopy using micro- and
radio-waves, it has recently been extended into the visible and UV spectral
range. However, resolving MHz energy splittings with ultrashort laser pulses
has still remained a challenge. Here, we analyze two-dimensional Fourier
spectra for resonant optical excitation of resident electrons to localized
trions or donor-bound excitons in semiconductor nanostructures subject to a
transverse magnetic field. Particular attention is devoted to Raman coherence
spectra which allow one to accurately evaluate tiny splittings of the electron
ground state and to determine the relaxation times in the electron spin
ensemble. A stimulated step-like Raman process induced by a sequence of two
laser pulses creates a coherent superposition of the ground state doublet which
can be retrieved only optically due to selective excitation of the same
sub-ensemble with a third pulse. This provides the unique opportunity to
distinguish between different complexes that are closely spaced in energy in an
ensemble. The related experimental demonstration is based on photon echo
measurements in an n-type CdTe/(Cd,Mg)Te quantum well structure detected by a
heterodyne technique. The difference in the sub-$\mu$eV range between the
Zeeman splittings of donor-bound electrons and electrons localized at potential
fluctuations can be resolved even though the homogeneous linewidth of the
optical transitions is larger by two orders of magnitude.",1701.01826v2
2020-01-17,Resonances in non-axisymmetric gravitational potentials,"We study sectoral resonances of the form $j\kappa= m(n-\Omega)$ around a
non-axisymmetric body with spin rate $\Omega$, where $\kappa$ and $n$ are the
epicyclic frequency and mean motion of a particle, respectively, where $j>0$
and $m$ ($<0$ or $>0$) are integers, $j$ being the resonance order. This
describes $n/\Omega \sim m/(m-j)$ resonances inside and outside the corotation
radius,as well as prograde and retrograde resonances. Results are: (1) the
kinematics of a periodic orbit depends only on $(m',j')$, the irreducible
(relatively prime) version of $(m,j)$. In a rotating frame, the periodic orbit
has $j'$ braids, $|m'|$ identical sectors and $|m'|(j'-1)$ self-crossing
points; (2) thus, Lindblad resonances (with $j=1$) are free of self-crossing
points; (3) resonances with same $j'$ and opposite $m'$ have the same
kinematics, and are called $twins$; (4) the order of a resonance at a given
$n/\Omega$ depends on the symmetry of the potential. A potential that is
invariant under a $2\pi/k$-rotation creates only resonances with $m$ multiple
of $k$; (5) resonances with same $j$ and opposite $m$ have the same kinematics
and same dynamics, and are called $true~twins$; (6) A retrograde resonance
($n/\Omega < 0$) is always of higher order than its prograde counterpart
($n/\Omega > 0$); (7) the resonance strengths can be calculated in a compact
form with the classical operators used in the case of a perturbing satellite.
Applications to Chariklo and Haumea are made.",2001.06382v1
2005-10-04,Wave Excitation in Three-Dimensional Disks by External Potential,"We study the excitation of density and bending waves and the associated
angular momentum transfer in gaseous disks with finite thickness by a rotating
external potential. The disk is assumed to be isothermal in the vertical
direction and has no self-gravity. The disk perturbations are decomposed into
different modes, each characterized by the azimuthal index m and the vertical
index n, which specifies the nodal number of the density perturbation along the
disk normal direction. The n=0 modes correspond to the two-dimensional density
waves previously studied by Goldreich & Tremaine and others. In a
three-dimensional disk, waves can be excited at both Lindblad resonances (for
modes with n=0,1,2...) and vertical resonances (for the $n\ge 1$ modes only).
The torque on the disk is positive for waves excited at outer Linblad/vertical
resonances and negative at inner Lindblad/vertical resonances. While the n=0
modes are evanescent around corotation, the $n\ge 1$ modes can propagate into
the corotation region where they are damped and deposit their angular momenta.
We have derived analytical expressions for the amplitudes of different wave
modes excited at Lindblad and/or vertical resonances and the resulting torques
on the disk. It is found that for $n\ge 1$, angular momentum transfer through
vertical resonances is much more efficient than Lindblad resonances. This
implies that in some situations (e.g., a circumstellar disk perturbed by a
planet in an inclined orbit), vertical resonances may be an important channel
of angular momentum transfer between the disk and the external potential. We
have also derived new formulae for the angular momentum deposition at
corotation and studied wave excitations at disk boundaries.",0510069v2
2000-09-22,Unitarity and Interfering Resonances in pipi Scattering and in Pion Production piN->pipiN,"Additivity of Breit-Wigner phases has been proposed to describe interfering
resonances in partial waves in $\pi\pi$ scattering. This assumption leads to an
expression for partial wave amplitudes that involves products of Breit-Wigner
amplitudes. We show that this expression is equivalent to a coherent sum of
Breit-Wigner amplitudes with specific complex coefficients which depend on the
resonance parameters of all contributing resonances. We use analyticity of
$\pi\pi$ partial wave amplitudes to show that they must have the form of a
coherent sum of Breit-Wigner amplitudes with complex coefficients and a complex
coherent background. The assumption of additivity of Breit-Wigner phases
restricts the partial waves to analytical functions with very specific form of
residues of Breit-Wigner poles. We argue that the general form provided by the
analyticity is more appropriate in fits to data to determine resonance
parameters. The partial wave unitarity can be imposed using the modern methods
of constrained optimization. We discuss unitarity and the production amplitudes
in $\pi N\to\pi\pi N$ and use analyticity in the dipion mass variable to
justify the common practice of writing the production amplitudes as a coherent
sum of Breit-Wigner amplitudes with free complex coefficients and a complex
coherent background in fits to mass spectra with interfering resonances.",0009275v2
2010-10-11,Wave functions for dynamically generated resonances; the two $Λ(1405)$ and $Λ(1670)$,"In this work we develop a formalism to evaluate wave functions in momentum
and coordinate space for the resonant states dynamically generated in a unitary
coupled channel approach. The on shell approach for the scattering matrix,
commonly used, is also obtained in Quantum Mechanics with a separable
potential, which allows one to write wave functions in a trivial way. We
develop useful relationships among the couplings of the dynamically generated
resonances to the different channels and the wave functions at the origin. The
formalism provides an intuitive picture of the resonances in the coupled
channel approach, as bound states of one bound channel, which decays into open
ones. It also provides an insight and practical rules for evaluating couplings
of the resonances to external sources and how to deal with final state
interaction in production processes. As an application of the formalism we
evaluate the wave functions of the two $\Lambda(1405)$ states in the $\pi
\Sigma$, $\bar{K} N$ and other coupled channels. It also offers a practical way
to study three body systems when two of them cluster into a resonance.",1010.2147v1
2023-10-02,Three- and four-wave resonances in the nonlinear quadratic Kelvin lattice,"In this paper we investigate analytically and numerically the nonlinear
Kelvin lattice, namely a chain of masses and nonlinear springs, as in the
alpha-Fermi-Pasta-Ulam-Tsingou (FPUT) chain, where, in addition, each mass is
connected to a nonlinear resonator, i.e., a second mass free to oscillate. Both
nonlinearities are quadratic in the equations of motion. This setup represents
the simplest prototype of nonlinear wave propagation on a nonlinear
metamaterial. In the linear case, we diagonalize the system, and the two
branches of the dispersion relation can be found. Using this result, we derive
in the nonlinear case the equations of motion for the normal variables in
Fourier space, obtaining a system governed by triad interactions among the two
branches of the dispersion relation. We find that the transfer of energy
between these two branches is ruled by three- and four-wave resonant
interactions. We perform numerical simulations of the primitive equations of
motion and highlight the role of resonances as an efficient mechanism for
transferring energy. Moreover, as predicted by the theory, we provide direct
evidence that four-wave resonances appear on a time scale that is longer than
the time scale for three-wave resonances. We also assess the recurrence
behaviour (usual in the FPUT system) for the nonlinear Kelvin lattice, and we
show that, while recurrence is observed if all the energy is placed, at time
t=0, in the lowest mode of the acoustical branch, a non-recurrent behaviour is
observed if the initial energy is located in the optical branch.",2310.02287v1
2023-11-03,Low-loss Millimeter-wave Resonators with an Improved Coupling Structure,"Millimeter-wave superconducting resonators are a useful tool for studying
quantum device coherence in a new frequency domain. However, improving
resonators is difficult without a robust and reliable method for coupling
millimeter-wave signals to 2D structures. We develop and characterize a tapered
transition structure coupling a rectangular waveguide to a planar slotline
waveguide with better than 0.5 dB efficiency over 14 GHz, and use it to measure
ground-shielded resonators in the W band (75 - 110 GHz). Having decoupled the
resonators from radiative losses, we consistently achieve single-photon quality
factors above $10^5$, with a two-level-system loss limit above $10^6$, and
verify the effectiveness of oxide removal treatments to reduce loss. These
values are 4-5 times higher than those previously reported in the W band, and
much closer to typical planar microwave resonators. The improved losses
demonstrated by these on-chip millimeter-wave devices shed new light on quantum
decoherence in a different frequency regime, offer increased selectivity for
high-frequency detectors, and enables new possibilities for hybrid quantum
experiments integrating millimeter-wave frequencies.",2311.01670v3
2000-09-27,Data Analysis of Continuous Gravitational Wave Signal: Fourier Transform,"We present the Fourier Transform of continuous gravitational wave for
arbitrary location of detector and source and for any duration of observation
time in which both rotational motion of earth about its spin axis and orbital
motion around sun has been taken into account. We also give the method to
account the spin down of continuous gravitational wave.",0009094v1
2002-09-26,Precession of a particle with anomalous magnetic moment in electromagnetic and gravitational pp-wave fields,"We present an exact solution of the Bargmann-Michel-Telegdi (BMT) equations
for the dynamics of a spin particle in external electromagnetic and
gravitational pp-wave fields. We demonstrate that an anomalous magnetic moment
gives rise to an additional spin rotation which is modulated both by the
electromagnetic and by the gravitational wave periodicities.",0209099v1
2003-01-30,Nuclear Wave Functions for Spin and Pseudospin Partners,"Using relations between wave functions obtained in the framework of the
relativistic mean field theory, we investigate the effects of pseudospin and
spin symmetry breaking on the single nucleon wave functions in spherical
nuclei. In our analysis, we apply both relativistic and non-relativistic
self-consistent models as well as the harmonic oscillator model.",0301098v1
2000-04-20,Spin accumulation in the semi classical and quantum regimes,"We consider spin accumulation at a ferromagnet--normal metal interface in the
presence of magnetic scattering in the normal metal. In the classical regime,
we discuss the inverse Drude scaling of the conductance as a function of the
interface transparencies. We present a treatment based on an exact solution of
the Boltzmann equation. In the quantum regime, we solve a single impurity
``spin-flip Fabry Perot interferometer'' for quantum coherent multiple
scatterings, in which we find a resonance in the spin flip channels. This
resonance appears to be the quantum analog of the semi classical inverse Drude
scaling of the conductance.",0004355v2
2001-05-27,Electron spin resonance in high-field critical phase of gapped spin chains,"Motivated by recent experiments on Ni(C_{2}H_{8}N_{2})_{2}Ni(CN)_{4}
(commonly known as NENC), we study the electron spin resonance in the critical
high-field phase of the antiferromagnetic S=1 chain with strong planar
anisotropy and show that the ESR spectra exhibit several peculiarities in the
critical phase. Possible relevance of those results for other gapped spin
systems is discussed.",0105515v1
2002-05-27,Destruction of the Kondo effect by a local measurement,"We show that the local spin measurement which decoheres the localized spin in
a Kondo system, suppresses the Abrikosov-Suhl resonance and destroys the Kondo
effect. This happens due to elimination of the entanglement between the
localized spin and the conduction electrons, and differs essentially from
smearing of the resonance by dissipation. Considering decoherence by a spin
bath, we predict that the Kondo effect disappears when the Kondo temperature
becomes smaller than the coupling with a bath. This effect can be detected in
experiments on ``quantum corrals'' or quantum dots doped by impurities with
internal degrees of freedom.",0205540v1
2002-10-09,Theory of spin relaxation in magnetic resonance force microscopy,"We study relaxation of a spin in magnetic resonance force microscopy (MRFM)
experiments. We evaluate the relaxation rate for the spin caused by
high-frequency mechanical noise of the cantilever under the conditions of
adiabatic spin inversion. We find qualitative agreement between the obtained
relaxation time and the experimental results of Stipe {\it et al.} [Phys. Rev.
Lett. 87, 277602 (2001)]. Based on our analysis, we propose a method for
improving the MRFM sensitivity by engineering cantilevers with reduced tip
positional fluctuations.",0210218v1
2004-02-28,Resonant Spin Hall Conductance in Two-Dimensional Electron Systems with Rashba Interaction in a Perpendicular Magnetic Field,"We study transport properties of a two-dimensional electron system with
Rashba spin-orbit coupling in a perpendicular magnetic field. The spin orbit
coupling competes with Zeeman splitting to introduce additional degeneracies
between different Landau levels at certain magnetic fields. This degeneracy, if
occuring at the Fermi level, gives rise to a resonant spin Hall conductance,
whose height is divergent as 1/T and whose weight is divergent as $-\ln T$ at
low temperatures. The Hall conductance is unaffected by the Rashba coupling.",0403005v1
2004-07-06,Spin characterization and control over the regime of radiation-induced zero-resistance states,"Over the regime of the radiation-induced zero-resistance states and
associated oscillatory magnetoresistance, we propose a low magnetic field
analog of quantum-Hall-limit techniques for the electrical detection of
electron spin- and nuclear magnetic- resonance, dynamical nuclear polarization
via electron spin resonance, and electrical characterization of the nuclear
spin polarization via the Overhauser shift. In addition, beats observed in the
radiation-induced oscillatory-magnetoresistance are developed into a method to
measure and control the zero-field spin splitting due to the Bychkov-Rashba and
bulk inversion asymmetry terms in the high mobility GaAs/AlGaAs system.",0407143v1
2007-03-07,Theory of resonant spin Hall effect,"A biref review is presented on resonant spin Hall effect, where a tiny
external electric field induces a saturated spin Hall current in a
2-dimensional electron or hole gas in a perpendicular magnetic field. The
phenomenon is attributted to the energy level crossing associated with the
spin-orbit coupling and the Zeeman splitting. We summarize recent theoretical
development of the effect in various systems and discuss possible experiments
to observe the effect.",0703176v1
2007-12-21,Nuclear spin relaxation induced by a mechanical resonator,"We report on measurements of the spin lifetime of nuclear spins strongly
coupled to a micromechanical cantilever as used in magnetic resonance force
microscopy. We find that the rotating-frame correlation time of the statistical
nuclear polarization is set by the magneto-mechanical noise originating from
the thermal motion of the cantilever. Evidence is based on the effect of three
parameters: (1) the magnetic field gradient (the coupling strength), (2) the
Rabi frequency of the spins (the transition energy), and (3) the temperature of
the low-frequency mechanical modes. Experimental results are compared to
relaxation rates calculated from the spectral density of the magneto-mechanical
noise.",0712.3792v1
2008-01-14,Dynamic nuclear polarization and spin-diffusion in non-conducting solids,"There has been much renewed interest in dynamic nuclear polarization (DNP),
particularly in the context of solid state biomolecular NMR and more recently
dissolution DNP techniques for liquids. This paper reviews the role of spin
diffusion in polarizing nuclear spins and discusses the role of the spin
diffusion barrier, before going on to discuss some recent results.",0801.2170v1
2008-05-02,Manipulating Spins by Cantilever Synchronized Frequency Modulation: A Variable Resolution Magnetic Resonance Force Microscope,"We report a new spin manipulation protocol for periodically reversing the
sample magnetization for Magnetic Resonance Force Microscopy. The protocol
modulates the microwave excitation frequency synchronously with the position of
the oscillating detection cantilever, thus allowing manipulation of the spin
magnetization independent of both magnetic field gradient strength and
cantilever response time. This allows continuous variation of the detected
sample volume and is effective regardless of spin relaxation rate. This
enhanced flexibility improves the utility of MRFM as a generally applicable
imaging and characterization tool.",0805.0266v1
2008-05-08,Scanning magnetic field microscope with a diamond single-spin sensor,"We describe a scanning device where a single spin is used as an
ultrasensitive, nanoscale magnetic field sensor. As this ""probe spin"" we
consider a single nitrogen-vacancy defect center in a diamond nanocrystal,
attached to the tip of the scanning device. Changes in the local field seen by
the probe spin are detected by optically monitoring its electron paramagnetic
resonance transition. The room-temperature scanning device may be useful for
performing nanoscale magnetic resonance imaging and spectroscopy, and for the
characterization of magnetic nanostructures down to the single atom level.",0805.1215v3
2009-08-21,Structure of a spin 1/2,"The non-hermitian states that lead to separation of the four Bell states are
examined. In the absence of interactions, a new quantum state of spin magnitude
1/(root(2) is predicted. Properties of these states show that an isolated spin
is a resonance state with zero net angular momentum, consistent with a point
particle, and each resonance corresponds to a degenerate but well defined
structure. By averaging and de-coherence these structures are shown to form
ensembles which are consistent with the usual quantum description of a spin.",0908.3219v1
2010-10-07,Two-spin relaxation of P-dimers in Silicon,"We study two-electron singlet-triplet relaxation of donor-bound electrons in
Silicon. Hyperfine interaction of the electrons with the phosphorus (P) nuclei,
in combination with the electron-phonon interaction, lead to relaxation of the
triplet states. Within the Heitler-London and effective mass approximations, we
calculate the triplet relaxation rates in the presence of an applied magnetic
field. This relaxation mechanism affects the resonance peaks in current
Electron Spin Resonance (ESR) experiments on P-dimers. Moreover, the estimated
time scales for the spin decay put an upper bound on the gate pulses needed to
perform fault-tolerant two-qubit operations in donor-spin-based quantum
computers (QCs).",1010.1513v1
2011-04-06,Quantum entanglement of a tunneling spin with mechanical modes of a torsional resonator,"We solve Schr\""odinger equation describing a tunneling macrospin coupled to a
torsional oscillator. Energy spectrum is studied for various quantum regimes.
Magnetic susceptibility and noise spectrum are computed. We show that
entanglement of the spin with mechanical modes of a subnanometer oscillator
results in the decoherence of spin tunneling. For larger oscillators the
presence of a tunneling spin can be detected through splitting of the
mechanical mode at the resonance. Our results apply to experiments with
magnetic molecules coupled to nanoresonators.",1104.1170v1
2011-06-03,Effective transition operators for resonant inelastic X-ray scattering,"Effective symmetry-based transition operators for resonant inelastic X-ray
scattering (RIXS) are derived that show how the scattering between different
states depends on the polarization of the incoming and outgoing X-rays. In
spherical symmetry, the effective operators can be rewritten in terms of spin
operators, although the expressions depend on the nature of the ground state.
For lower symmetries, the combined action of the crystal field and the
spin-orbit interaction breaks up the spin space and spin operators are no
longer appropiate operators. By taking iridium compounds as an example, it is
demonstrated that effective scattering operators can still be obtained. These
effective transition operators facilitate our understanding how RIXS couples to
elementary excitations.",1106.0640v1
2013-07-03,Large Spin Pumping from Epitaxial Y3Fe5O12 Thin Films to Pt and W Layers,"Epitaxial Y3Fe5O12 thin films have been deposited by off-axis sputtering,
which exhibit excellent crystalline quality, enabling observation of large spin
pumping signals in Pt/Y3Fe5O12 and W/Y3Fe5O12 bilayers driven by cavity
ferromagnetic resonance. The inverse spin Hall voltages reach 2.10 mV and -5.26
mV in 5-mm long Pt/Y3Fe5O12 and W/Y3Fe5O12 bilayers, respectively, excited by a
radio-frequency magnetic field of 0.3 Oe. From the ferromagnetic resonance
linewidth broadening, the interfacial spin mixing conductance of 4.56E14
{\Omega}-1m-2 and 2.30E14 {\Omega}-1m-2 are obtained for Pt/Y3Fe5O12 and
W/Y3Fe5O12 bilayers, respectively.",1307.1172v1
2013-08-01,Power dependence of electric dipole spin resonance,"We develop a formalism of electric dipole spin resonance (EDSR) based on
slanting magnetic field, where we especially investigate the microwave
amplitude dependence. With increasing microwave amplitude, the Rabi frequency
increases linearly for a spin confined in a harmonic potential. How- ever, when
the spin is confined in the double-well potential, the Rabi frequency shows
sub-linear dependence with increasing the microwave amplitude.",1308.0071v1
2014-11-26,General Magnetic Transition Dipole Moments for Electron Paramagnetic Resonance,"We present general expressions for the magnetic transition rates in beam
Electron Paramagnetic Resonance (EPR) experiments of anisotropic spin systems
in the solid state. The expressions apply to general spin centers and arbitrary
excitation geometry (Voigt, Faraday, and intermediate). They work for linear
and circular polarized as well as unpolarized excitation, and for crystals and
powders. The expressions are based on the concept of the (complex) magnetic
transition dipole moment vector. Using the new theory, we determine the
parities of ground and excited spin states of high-spin (S = 5/2) Fe(III) in
hemin from the polarization dependence of experimental ground state EPR line
intensities.",1411.7187v1
2016-04-15,Electron magnetic resonance in magnetic nanoparticles: dependence on the particle size and applicability of the modified giant spin model,"Superparamagnetic nanoparticles containing hundreds and thousands of coupled
electron spins are on the boundary between classical and quantum behavior, and
demonstrate features which are typical for paramagnetic spins and absent in
macroscopic ferromagnetic systems. In order to better understand the evolution
of magnetization dynamics from quantum to classical behavior with the increase
in the system size, we study the electron magnetic resonance signal in
suspensions of iron oxide nanoparticles as the function of the particle size.
The experimental data are compared with numerical simulations based on the
giant spin approach.",1604.04594v2
2016-05-10,Coherently coupling distinct spin ensembles through a high-$T_c$ superconducting resonator,"The problem of coupling multiple spin ensembles through cavity photons is
revisited by using PyBTM organic radicals and a high-$T_c$ superconducting
coplanar resonator. An exceptionally strong coupling is obtained and up to
three spin ensembles are simultaneously coupled. The ensembles are made
physically distinguishable by chemically varying the $g$ factor and by
exploiting the inhomogeneities of the applied magnetic field. The coherent
mixing of the spin and field modes is demonstrated by the observed multiple
anticrossing, along with the simulations performed within the input-output
formalism, and quantified by suitable entropic measures.",1605.02879v1
2017-09-21,Optical bistability under non-resonant excitation in spinor polariton condensates,"We realise bistability in the spinor of polariton condensates under
non-resonant optical excitation and in the absence of biasing external fields.
Numerical modelling of the system using the Ginzburg-Landau equation with an
internal Josephson coupling between the two spin components of the condensate
qualitatively describes the experimental observations. We demonstrate that
polariton spin bistability persists for sweep times in the range of $[10 \mu
sec,1 sec]$ offering a promising route to spin switches and spin memory
elements.",1709.07351v1
2014-06-26,Boundary between the thermal and statistical polarization regimes in a nuclear spin ensemble,"As the number of spins in an ensemble is reduced, the statistical uctuations
in its polarization eventually exceed the mean thermal polarization. This
transition has now been surpassed in a number of recent nuclear magnetic
resonance experiments, which achieve nanometer-scale detection volumes. Here,
we measure nanometer- scale ensembles of nuclear spins in a KPF6 sample using
magnetic resonance force microscopy. In particular, we investigate the
transition between regimes dominated by thermal and statistical nuclear
polarization. The ratio between the two types of polarization provides a
measure of the number of spins in the detected ensemble.",1406.6869v2
2020-03-20,Electron Spin Resonance with up to 20 Spin Sensitivity Measured using a Superconducting Flux Qubit,"We report on electron spin resonance spectroscopy measurements using a
superconducting flux qubit with a sensing volume of 6 fl. The qubit is read out
using a frequency-tunable Josephson bifurcation amplifier, which leads to an
inferred measurement sensitivity of about 20 spins in a 1 s measurement. This
sensitivity represents an order of magnitude improvement when compared with
flux-qubit schemes using a dc-SQUID switching readout. Furthermore, noise
spectroscopy reveals that the sensitivity is limited by flicker ($1/f$) flux
noise.",2003.09131v1
2020-02-20,Thermal rectification and spin-spin coupling of non-reciprocal localized and surface modes,"We study the rectification of near-field radiative heat transfer between two
InSb nano-particles due to the presence of non-reciprocal surface modes in a
nearby InSb sample when an external magnetic field is applied and its
dependence on the magnetic field strength. We reveal the spin-spin coupling
mechanism of the localized particle resonances and the surface mode resonances
which is substantiated by the directional heat flux in the given setup. We
discuss further the interplay of the frequency shift, the propagation length,
and local density of states on the strength and directionality of the
rectification as well as the non-reciprocal heating effect of the
nanoparticles.",2002.08752v1
2021-03-10,Anisotropic superconducting spin transport at magnetic interfaces,"We present a theoretical investigation of anisotropic superconducting spin
transport at a magnetic interface between a p-wave superconductor and a
ferromagnetic insulator. Our formulation describes the ferromagnetic resonance
modulations due to spin current generation depending on spin-triplet Cooper
pair, including the frequency shift and enhanced Gilbert damping, in a unified
manner. We find that the Cooper pair symmetry is detectable from the
qualitative behavior of the ferromagnetic resonance modulation. Our theory
paves the way toward anisotropic superconducting spintronics.",2103.05871v3
2023-07-18,Electron spin resonance study on the 4f honeycomb quantum magnet YbCl3,"The local magnetic properties of Yb$^{3+}$ in the layered honeycomb material
YbCl$_{3}$ were investigated by electron spin resonance on single crystals. For
in-plane and out-of-plane field orientations the $g$-factor shows a clear
anisotropy ($g_\|=2.97(8)$ and $g_\bot =1.53(4)$), whereas the low temperature
exchange coupling and the spin relaxation display a rather isotropic character.
At elevated temperatures the contribution of the first excited crystal field
level ($21\pm2$~meV) dominates the spin relaxation.",2307.09335v1
2010-05-12,Turbulence of capillary waves revisited,"Kinetic regime of capillary wave turbulence is classically regarded in terms
of three-wave interactions with the exponent of power energy spectrum being
$\nu=-7/4$ (two-dimensional case). We show that a number of assumptions
necessary for this regime to occur can not be fulfilled. Four-wave interactions
of capillary waves should be taken into account instead, which leads to
exponents $\nu=-13/6$ and $\nu=-3/2$ for one- and two-dimensional wavevectors
correspondingly. It follows that for general dispersion functions of decay
type, three-wave kinetic regime need not prevail and higher order resonances
may play a major role.
  Accepted for publication.",1005.2067v3
2012-08-21,Gravitational waves from smooth hybrid new infation,"We calculate the production of the gravitational waves from a double
inflation model with lattice simulations. Between the two inflationary stages,
gravitational waves with a characteristic frequency are produced by
fluctuations of the scalar fields enhanced through parametric resonance. The
wavelength of the produced gravitational waves gets extra redshift during the
second inflationary stage and it can be in the observable range for the direct
gravitational wave detectors. It is found that there is a possibility for the
produced gravitational waves to be detected in the planned experiments.",1208.4160v2
2016-02-26,Tree-wave mixing of ordinary and backward electromagnetic waves: extraordinary transients,"Three-wave mixing of ordinary and backward electromagnetic waves in pulsed
regime is investigated in the metamaterials, which enable co-existence and
phase matching of such waves. It is shown that opposite direction of phase
velocity and energy flux in backward waves gives rise to extraordinary
transient processes in greatly enhanced optical parametric amplification and in
frequency up or down shifting nonlinear reflectivity. The discovered transients
resemble slowed response of an oscillator on pulsed excitation in the vicinity
of its resonance",1602.08217v1
2016-04-25,Complete Hamiltonian formalism for inertial waves in rotating fluids,"Complete Hamiltonian formalism is suggested for inertial waves in rotating
incompressible fluid. Resonance three-wave interaction processes -- decay
instability and confluence of two waves -- are shown to play a key role in the
weakly nonlinear dynamics and statistics of inertial waves in the rapid
rotation case. Future applications of the Hamiltonian approach in inertial wave
theory are investigated and discussed.",1604.07136v2
2017-02-13,On the kinetic equation in Zakharov's wave turbulence theory for capillary waves,"The wave turbulence equation is an effective kinetic equation that describes
the dynamics of wave spectrum in weakly nonlinear and dispersive media. Such a
kinetic model has been derived by physicists in the sixties, though the
well-posedness theory remains open, due to the complexity of resonant
interaction kernels. In this paper, we provide a global unique radial strong
solution, the first such a result, to the wave turbulence equation for
capillary waves.",1702.03892v2
2017-03-08,A generalized action-angle representation of wave interaction in stratified shear flows,"In this paper we express the linearized dynamics of interacting interfacial
waves in stratified shear flows in the compact form of action-angle Hamilton
equations. The pseudo-energy serves as the Hamiltonian of the system, the
action coordinates are the contribution of the interfacial waves to the
wave-action, and the angles are their phases. The term ""generalized
action-angle"" aims to emphasize that the action of each wave is generally time
dependent and this allows instability. An attempt is made to relate this
formalism to the action at a distance resonance instability mechanism between
counter-propagating vorticity waves via the global conservations of
pseudo-energy and pseudo-momentum.",1703.03032v2
2021-11-27,Three-wave interactions and strange attractor,"It is shown that the incorporation of linear sink/source terms in the
three-wave resonance interaction model results in the time dependence of the
wave amplitudes, which could exhibit the properties of a strange attractor.
This finding demonstrates that the transition to turbulent dynamics of the
waves could be related not only to the coupling of wave triads but also to the
establishing of the strange attractor-like dynamics within individual wave
triads.",2111.13937v1
2009-04-07,Probabilistic Interpretation of Resonant States,"We provide probabilistic interpretation of resonant states. This we do by
showing that the integral of the modulus square of resonance wave functions
(i.e., the conventional norm) over a properly expanding spatial domain is
independent of time, and therefore leads to probability conservation. This is
in contrast with the conventional employment of a bi-orthogonal basis that
precludes probabilistic interpretation, since wave functions of resonant states
diverge exponentially in space. On the other hand, resonant states decay
exponentially in time, because momentum leaks out of the central scattering
area. This momentum leakage is also the reason for the spatial exponential
divergence of resonant state. It is by combining the opposite temporal and
spatial behaviors of resonant states that we arrive at our probabilistic
interpretation of these states. The physical need to normalize resonant wave
functions over an expanding spatial domain arises because particles leak out of
the region which contains the potential range and escape to infinity, and one
has to include them in the total count of particle number.",0904.1044v2
2022-06-20,Parametrically-driven temporal cavity solitons in a bichromatically-driven pure Kerr resonator,"Temporal cavity solitons (CSs) are pulses of light that can persist endlessly
in dispersive, nonlinear optical resonators. They have been extensively studied
in the context of resonators with purely cubic (Kerr-type) nonlinearity that
are externally-driven with a monochromatic continuous wave laser -- in such
systems, the solitons manifest themselves as unique attractors whose carrier
frequency coincides with that of the external driving field. Recent experiments
have, however, shown that a qualitatively different type of temporal CS can
arise via parametric down-conversion in resonators with simultaneous quadratic
and cubic nonlinearity. In contrast to conventional CSs in pure-Kerr
resonators, these \emph{parametrically-driven cavity solitons} come in two
different flavours with opposite phases, and they are spectrally centred at
half of the frequency of the driving field. Here, we theoretically and
numerically show that, under conditions of bichromatic driving, such
parametrically-driven CSs can also arise in dispersive resonators with pure
Kerr nonlinearity. In this case, the solitons arise through parametric
four-wave mixing, come with two distinct phases, and have a carrier frequency
in between the two external driving fields. We show that, when all waves are
resonant, the solitons can experience long-range interactions due to their
back-action on the intracavity fields at the pump frequencies, and we discuss
the parameter requirements for the solitons' existence. Besides underlining the
possibility of exciting a new type of cavity soliton in dispersive Kerr
cavities, our work advances the theoretical modeling of resonators that are
coherently-driven with polychromatic fields.",2206.09533v1
1996-03-18,Renormalization-Group Approach to Spin-Wave Theory of Quantum Heisenberg Ferromagnet,"The renormalization-group method is used to analyze the low-temperature
behaviour of a two-dimentional, spin-$s$ quantum Heisenberg ferromagnet. A set
of recursion equations is derived in an one-loop approximation. The
low-temperature asymptotics of the correlation length and the uniform
susceptibility are obtained. For small spins ($s= 1/2,1$) the results are
essentially different from those in the spin-wave theory.",9603123v1
2004-04-22,On the theory of polarized Fermi liquid,"The transport equation for transverse vibrations of magnetization in spin
polarized Fermi liquid is derived from integral equation for the vertex
function. The dispersion law for the transverse spin waves is established. The
existance of zero-temperature spin-waves attenuation is confirmed. The problem
of similar derivation in ferromagnetic ""Fermi liquid"" is discussed.",0404539v1
1997-10-02,Pseudo-spin Symmetry and Relativistic Single-nucleon Wave Functions,"We show that the occurrence of approximate pseudo-spin symmetry in nuclei is
connected with certain similarities in the relativistic single-nucleon wave
functions of the corresponding pseudo-spin doublets. We perform a case study in
which several examples and the systematics of this connection are explored.",9710011v1
1998-02-17,Electromagnetic Waves in the Vacuum with Torsion and Spin,"Exact radiative wave solutions to the classical homogeneous Maxwell equations
in the vacuum have been found that are not transverse, exhibit both torsion and
spin, and for which the second Poincare invariant, E.B, is not zero. Two four
component rank 3 tensors of spin current and torsion are constructed on
topological grounds. The divergence of each pseudo vector generates the
Poincare invariants of the electromagnetic system.",9802033v1
2009-07-09,Nuclear spin-density wave theory,"Recently [arXiv:0906.5417], we reported a quantum phase transition of 103mRh
excited by bremsstrahlung pumping. The long-lived Moessbauer excitation is
delocalized as a neutral quasiparticle carrying a spin current. This letter
gives a general theory for a nuclear spin-density wave propagating on crystals
consisting of identical nuclei with a multipolar transition.",0907.1446v2
2004-03-01,Density waves in the shearing sheet IV. Interaction with a live dark halo,"It is shown that if the self-gravitating shearing sheet, a model of a patch
of a galactic disk, is embedded in a live dark halo, this has a strong effect
on the dynamics of density waves in the sheet. I describe how the density waves
and the halo interact via halo particles either on orbits in resonance with the
wave or on non-resonant orbits. Contrary to expectation the presence of the
halo leads to a very considerable enhancement of the amplitudes of the density
waves in the shearing sheet. This effect appears to be the equivalent of the
recently reported enhanced growth of bars in numerically simulated stellar
disks embedded in live dark halos. Finally I discuss the transfer of linear
momentum from a density wave in the sheet to the halo and show that it is
mediated only by halo particles on resonant orbits.",0403027v1
2005-03-09,Perturbative analysis of wave interactions in nonlinear systems,"This work proposes a new way for handling obstacles to asymptotic
integrability in perturbed nonlinear PDEs within the method of Normal Forms -
NF - for the case of multi-wave solutions. Instead of including the whole
obstacle in the NF, only its resonant part is included, and the remainder is
assigned to the homological equation. This leaves the NF intergable and its
solutons retain the character of the solutions of the unperturbed equation. We
exploit the freedom in the expansion to construct canonical obstacles which are
confined to te interaction region of the waves. Fo soliton solutions, e.g., in
the KdV equation, the interaction region is a finite domain around the origin;
the canonical obstacles then do not generate secular terms in the homological
equation. When the interaction region is infifnite, or semi-infinite, e.g., in
wave-front solutions of the Burgers equation, the obstacles may contain
resonant terms. The obstacles generate waves of a new type, which cannot be
written as functionals of the solutions of the NF. When an obstacle contributes
a resonant term to the NF, this leads to a non-standard update of th wave
velocity.",0503019v1
2008-10-29,Mechanism of Terahertz Electromagnetic Wave Emission from Intrinsic Josephson Junctions,"Using a 3-D parallelepiped model of intrinsic Josephson junctions, we
calculate the cavity resonance modes of Josephson plasma waves excited by
external electric currents. The electromagnetic (EM) wave of the excited
Josephson plasma is converted to a THz EM wave at the sample surfaces. The
cavity modes accompanied by static phase kinks of the superconducting order
parameter have been intensively investigated. The phase kinks induce a spatial
modulation of the amplitude of the order parameter around the kinks and
decrease the superconducting condensation energy. The Josephson plasma produces
a magnetic field in the vacuum in addition to the emitted EM wave. This
magnetic energy detemines the orientation of the cavity mode. Taking account of
the facts mentioned above, we obtained sharp resonance peaks in the I-V curves
and sizable powers of continuous and coherent terahertz wave emission at the
cavity resonance. The emission frequencies are inversely proportional to the
length of the shorter side of the samples in agreement with experiments.",0810.5268v1
2009-07-03,Inertial waves near corotation in 3D hydrodynamical disks,"This paper concerns the interaction between non-axisymmetric inertial waves
and their corotation resonances in a hydrodynamical disk. Inertial waves are of
interest because they can localise in resonant cavities circumscribed by
Lindblad radii, and as a consequence exhibit discrete oscillation frequencies
that may be observed. It is often hypothesised that these trapped eigenmodes
are affiliated with the poorly understood QPO phenomenon. We demonstrate that a
large class of non-axisymmetric 3D inertial waves cannot manifest as trapped
normal modes. This class includes any inertial wave whose resonant cavity
contains a corotation singularity. Instead, these `singular' modes constitute a
continuous spectrum and, as an ensemble, are convected with the flow, giving
rise to shearing waves. Lastly, we present a simple demonstration of how the
corotation singularity stabilizes three-dimensional perturbations in a slender
torus.",0907.0641v3
2012-12-22,Run-up amplification of transient long waves,"The extreme characteristics of long wave run-up are studied in this paper.
First we give a brief overview of the existing theory which is mainly based on
the hodograph transformation (Carrier & Greenspan, 1958). Then, using numerical
simulations, we build on the work of Stefanakis et al. (2011) for an infinite
sloping beach and we find that resonant run-up amplification of monochromatic
waves is robust to spectral perturbations of the incoming wave and resonant
regimes do exist for certain values of the frequency. In the setting of a
finite beach attached to a constant depth region, resonance can only be
observed when the incoming wavelength is larger than the distance from the
undisturbed shoreline to the seaward boundary. Wavefront steepness is also
found to play a role in wave run-up, with steeper waves reaching higher run-up
values.",1212.5689v3
2015-05-20,Nonlinear Low-to-High Frequency Energy Cascades in Diatomic Granular Crystals,"We study wave propagation in strongly nonlinear 1D diatomic granular crystals
under an impact load. Depending on the mass ratio of the `light' to `heavy'
beads, this system exhibits rich wave dynamics from highly localized traveling
waves to highly dispersive waves featuring strong attenuation. We
experimentally demonstrate the nonlinear resonant and anti-resonant
interactions of particles and verify that the nonlinear resonance results in
strong wave attenuation, leading to highly efficient nonlinear energy cascading
without relying on material damping. In this process, mechanical energy is
transferred from low to high frequencies, while propagating waves emerge in
both ordered and chaotic waveforms via a distinctive spatial cascading. This
energy transfer mechanism from lower to higher frequencies and wavenumbers is
of particular significance towards the design of novel nonlinear acoustic
metamaterials with inherently passive energy redistribution properties.",1505.05556v2
2016-09-18,Semiclassical soliton ensembles for the three-wave resonant interaction equations,"The three-wave resonant interaction equations are a non-dispersive system of
partial differential equations with quadratic coupling describing the time
evolution of the complex amplitudes of three resonant wave modes. Collisions of
wave packets induce energy transfer between different modes via pumping and
decay. We analyze the collision of two or three packets in the semiclassical
limit by applying the inverse-scattering transform. Using WKB analysis, we
construct an associated semiclassical soliton ensemble, a family of
reflectionless solutions defined through their scattering data, intended to
accurately approximate the initial data in the semiclassical limit. The map
from the initial packets to the soliton ensemble is explicit and amenable to
asymptotic and numerical analysis. Plots of the soliton ensembles indicate the
space-time plane is partitioned into regions containing either quiescent,
slowly varying, or rapidly oscillatory waves. This behavior resembles the
well-known generation of dispersive shock waves in equations such as the
Korteweg-de Vries and nonlinear Schrodinger equations, although the physical
mechanism must be different in the absence of dispersion.",1609.05416v1
2018-11-02,Effect of Inner Lindblad Resonance on Spiral Density Waves Propagation in Disc Galaxies: Reflection over Absorption,"Interaction of spiral density waves with stars in the vicinity of the inner
Lindblad resonance in galactic discs is investigated using the linear
perturbation theory and the leading orders in the epicyclic and WKB
approximations. In analogy with shear flows in hydrodynamics, we conjecture
that a weak nonlinearity in a narrow resonance region modifies the standard
(Landau-Lin) bypass rule of the singularity to the integration in the principal
value sense. This indeed leads to the reflection of the spiral wave instead of
absorption, but the detailed picture looks awkward: the intervals of the wave
weakening alternate with the intervals of the wave growth, so that the net
absorption is absent. Incidentally, we rectify the result concerning leading
spiral waves obtained earlier for the standard bypass rule.",1811.00847v1
2019-11-01,A tunable High-Q millimeter wave cavity for hybrid circuit and cavity QED experiments,"The millimeter wave (mm-wave) frequency band provides exciting prospects for
quantum science and devices, since many high-fidelity quantum emitters,
including Rydberg atoms, molecules and silicon vacancies, exhibit resonances
near 100 GHz. High-Q resonators at these frequencies would give access to
strong interactions between emitters and single photons, leading to rich and
unexplored quantum phenomena at temperatures above 1K. We report a 3D mm-wave
cavity with a measured single-photon internal quality factor of $3 \times
10^{7}$ and mode volume of $0.14 \times \lambda^3$ at $98.2$ GHz, sufficient to
reach strong coupling in a Rydberg cavity QED system. An in-situ piezo
tunability of $18$ MHz facilitates coupling to specific atomic transitions. Our
unique, seamless and optically accessible resonator design is enabled by the
realization that intersections of 3D waveguides support tightly confined bound
states below the waveguide cutoff frequency. Harnessing the features of our
cavity design, we realize a hybrid mm-wave and optical cavity, designed for
interconversion and entanglement of mm-wave and optical photons using Rydberg
atoms.",1911.00553v1
2020-08-07,Quantifying the evidence for resonant damping of coronal waves with foot-point wave power asymmetry,"We use Coronal Multi-channel Polarimeter (CoMP) observations of propagating
waves in the solar corona and Bayesian analysis to assess the evidence of
models with resonant damping and foot-point wave power asymmetries. Two nested
models are considered. The reduced model considers resonant damping as the sole
cause of the measured discrepancy between outward and inward wave power. The
larger model contemplates an extra source of asymmetry with origin at the
foot-points. We first compute probability distributions of parameters
conditional on the models and the observed data. The obtained constraints are
then used to calculate the evidence for each model in view of data. We find
that we need to consider the larger model to explain CoMP data and to
accurately infer the damping ratio, hence, to better assess the possible
contribution of the waves to coronal heating.",2008.03004v1
2020-09-17,Resonant absorption: transformation of compressive motions into vortical motions,"This paper investigates the changes in spatial properties when
magnetohydrodynamic (MHD) waves undergo resonant damping in the Alfv\'en
continuum. The analysis is carried out for a 1D cylindrical pressure-less
plasma with a straight magnetic field. The effect of the damping on the spatial
wave variables is determined by using complex frequencies that arise as a
result of the resonant damping. Compression and vorticity are used to
characterise the spatial evolution of the MHD wave. The most striking result is
the huge spatial variation in the vorticity component parallel to the magnetic
field. Parallel vorticity vanishes in the uniform part of the equilibrium.
However, when the MHD wave moves into the non-uniform part, parallel vorticity
explodes to values that are orders of magnitude higher than those attained by
the transverse components in planes normal to the straight magnetic field. In
the non-uniform part of the equilibrium plasma, the MHD wave is controlled by
parallel vorticity and resembles an Alfv\'en wave, with the unfamiliar property
that it has pressure variations even in the linear regime.",2009.08152v1
2021-04-09,An alternative form of the fundamental plasma emission through the coalescence of Z-mode waves with whistlers,"Plasma emission (PE), i.e., electromagnetic radiation at the plasma frequency
and its second harmonic, is a general process occurring in both astrophysical
and laboratory plasmas. The prevailing theory presents a multi-stage process
attributed to the resonant coupling of beam-excited Langmuir waves with
ion-acoustic waves. Here we examine another possibility of the fundamental PE
induced by the resonant coupling of Z-mode and whistler (W) waves. Earlier
studies have been controversial in the plausibility and significance of such
process in plasmas. In this study we show that the matching condition of three
wave resonant interaction (Z+W ! O) can be satisfied over a wide regime of
parameters based on the magnetoionic theory, demonstrate the occurrence of such
process and further evaluate the rate of energy conversion from the pumped Z or
W mode to the fundamental O mode with particle-in-cell (PIC) simulations of
wave pumping. The study presents an alternative form of the fundamental PE,
which could possibly play a role in various astrophysical and laboratory
scenarios with both Z and W modes readily excited through the electron
cyclotron maser instability.",2104.04267v1
2022-09-01,Pedal underwater motion triggers highly-peaked resonance on water waves,"Pedal wavemakers that generate surface gravity waves through bed orbital
motion have been shown to produce particle-excursion patterns that mimic
deep-water wave behaviour but in finite-depth channels. In this article, we
report that gravity waves in a general viscous fluid can resonate through the
action of pedal wavemakers. We analyse the linear response of waves in an
infinite channel in terms of the displacement amplitude, frequency, and
wavelength of the bottom action. We show that the system behaves as a long-pass
filter in space and a high-pass filter in time with a sharp resonance affected
by viscosity. Furthermore, we propose a protocol to design deep gravity waves
with an on-demand wavelength in a finite-depth water channel. Our theoretical
framework agrees with numerical simulations using Smoothed Particle
Hydrodynamics. Our results thus quantify the performance of pedal wavemakers
and provide essential formulas for industrial and computational applications of
the pedal wavemaking technique, useful both in hydraulics and coastal
engineering problems.",2209.00748v1
2023-05-01,Novel high-frequency gravitational waves detection with split cavity,"Gravitational waves can generate electromagnetic effects inside a strong
electric or magnetic field within the Standard Model and general relativity.
Here we propose using a quarterly split cavity and LC(inductor and
capacitor)-resonance circuit to detect a high-frequency gravitational wave from
0.1 MHz to GHz. We perform a full 3D simulation of the cavity's signal for
sensitivity estimate. Our sensitivity depends on the coherence time scale of
the high-frequency gravitational wave sources and the volume size of the split
cavity. We discuss the resonant measurement schemes for narrow-band
gravitational wave sources and also a non-resonance scheme for broadband
signals. For a meter-sized split cavity under a 14 Tesla magnetic field, the LC
resonance enhanced sensitivity to the gravitational wave strain is expected to
reach $h\sim 10^{-20}$ around $10$ MHz.",2305.00877v2
2003-01-23,The spin of the mesons and baryons,"It is shown that the spin of pi (0), eta, Lambda, Sigma (+,-,0), Xi (-,0),
Lambda-c (+), Sigma-c (0), Xi-c (0), and Omega-c (0) mesons and baryons can be
explained by the sum of the angular momentum vectors and spin vectors of the
electromagnetic waves which are in these particles according to the standing
wave model. The spin of the pi (+,-), K (+,-,0), D (+,-,0), and D-S (+,-)
mesons and of the neutron is the sum of the angular momentum vectors of the
oscillations and of the spin vectors of the neutrinos and the electric charges
which are in the cubic lattice of these particles. Spin 1/2 is the consequence
of the superposition of two perpendicular standing waves of equal frequencies
and amplitudes shifted in phase by pi/2. The spin of the antiparticles of the
mesons and baryons is the same as the spin of the ordinary particles.",0301060v3
2004-09-18,Spin wave based quantum storage of electronic spin with a ring array of nuclear spins,"We propose a solid state based protocol to implement the universal quantum
storage for electronic spin qubit. The quantum memory in this scheme is the
spin wave excitation in the ring array of nuclei in a quantum dot. We show that
the quantum information carried by an arbitrary state of the electronic spin
can be coherently mapped onto the spin wave excitations or the magnon states.
With an appropriate external control, the stored quantum state in quantum
memory can be read out reversibly. We also explore in detail the quantum
decoherence mechanism due to the inhomogeneous couplings between the electronic
spin and the nuclear spins.",0409120v3
2011-10-13,Competing Hyperfine and Spin-Orbit Couplings: Spin Relaxation in a Quantum Hall Ferromagnet,"Spin relaxation in a quantum Hall ferromagnet, where filling is $\nu=1, 1/3,
1/5,...$, can be considered in terms of spin wave annihilation/creation
processes. Hyperfine coupling with the nuclei of the GaAs matrix provides spin
non-conservation in the two-dimensional electron gas and determines spin
relaxation in the quantum Hall system. This mechanism competes with spin-orbit
coupling channels of spin-wave decay and can even dominate in a low-temperature
regime where $T$ is much smaller than the Zeeman gap. In this case the
spin-wave relaxation process occurs non-exponentially with time and does not
depend on the temperature. The competition of different relaxation channels
results in crossovers in the dominant mechanism, leading to non-monotonic
behavior of the characteristic relaxation time with the magnetic field. We
predict that the relaxation times should reach maxima at $B\simeq 18\,$T in the
$\nu=1$ Quantum Hall system and at $B\simeq 12\,$T for that of $\nu=1/3\,$. We
estimate these times as $\sim10\,-\,30\,\mu$s and $\sim2\,-\,5\,\mu$s,
respectively.",1110.3006v1
2011-11-21,Wave-diffusion theory of spin transport in metals after ultrashort-pulse excitation,"Spin and charge-current dynamics after ultrafast spin-polarized excitation in
a normal metal are studied theoretically using a wave-diffusion theory. It is
shown analytically how this macroscopic approach correctly describes the
ballistic and diffusive properties of spin and charge transport, but also
applies to the intermediate regime between these two limits. Using the
wave-diffusion equations we numerically analyze spin and charge dynamics after
ultrafast excitation of spin polarized carriers in thin gold films. Assuming
slightly spin-dependent momentum relaxation times, we find that a unified
treatment of diffusive and ballistic transport yields robust signatures in the
spin and charge dynamics, which are in qualitative agreement with recent
experimental results [Phys. Rev. Lett 107, 076601 (2011)]. The influence of
boundary effects on the temporal signatures of spin transport is also studied.",1111.4780v1
2016-06-05,Spin current contribution in the spectrum of collective excitations of degenerate partially polarized spin-1/2 fermions at separate dynamics of spin-up and spin-down fermions,"The spectrum of collective excitations of degenerate partially polarized
spin-1/2 fermions is considered. The spin-up fermions and the spin-down
fermions are considered as different fluids. Corresponding two-fluid
hydrodynamics consistent with a non-linear Pauli equation is suggested. An
equation of state for the spin current caused by the distribution of particles
on different energy levels is suggested for the degenerate regime, where the
spin current is caused by the Pauli blocking. Spectrum of three waves is found
as a solution of the hydrodynamic equations: two sound waves and one spin wave.
Their spectrums are calculated for two regimes: propagation parallel and
perpendicular to the direction of the equilibrium spin polarization.",1606.01562v2
2019-11-13,Tailoring spin wave channels in a reconfigurable artificial spin ice,"Artificial spin ices are ensembles of geometrically-arranged, interacting
nanomagnets which have shown promising potential for the realization of
reconfigurable magnonic crystals. Such systems allow for the manipulation of
spin waves on the nanoscale and their potential use as information carriers.
However, there are presently two general obstacles to the realization of
artificial spin ice-based magnonic crystals: the magnetic state of artificial
spin ices is difficult to reconfigure and the magnetostatic interactions
between the nanoislands are often weak, preventing mode coupling. We
demonstrate, using micromagnetic modeling, that coupling a reconfigurable
artificial spin ice geometry made of weakly interacting nanomagnets to a soft
magnetic underlayer creates a complex system exhibiting dynamically coupled
modes. These give rise to spin wave channels in the underlayer at well-defined
frequencies, based on the artificial spin ice magnetic state, which can be
reconfigured. These findings open the door to the realization of reconfigurable
magnonic crystals with potential applications for data transport and processing
in magnonic-based logic architectures.",1911.05354v4
2020-02-13,Dynamical spin susceptibility of spin-valley half-metal,"A few years ago we predicted theoretically that in systems with nesting of
the Fermi surface the spin-valley half-metal has lower energy than the spin
density wave state. In this paper we suggest a possible way to distinguish
these phases experimentally. We calculate dynamical spin susceptibility tensor
for both states in the framework of the Kubo formalism. Discussed phases have
different numbers of the bands: four bands in the spin-valley half-metal and
only two bands in the spin density wave. Therefore, their susceptibilities, as
functions of frequency, have different number of peaks. Besides, the
spin-valley half-metal does not have rotational symmetry, thus, in general the
off-diagonal components of susceptibility tensor are non-zero. The spin density
wave obeys robust rotational symmetry and off-diagonal components of the
susceptibility tensor are zero. These characteristic features can be observed
in experiments with inelastic neutron scattering.",2002.05504v1
2021-03-14,Gapless spin liquid and pair density wave of the Hubbard model on three-leg triangular cylinders,"We study the ground state properties of the Hubbard model on three-leg
triangular cylinders using large-scale density-matrix renormalization group
simulations. At half-filling, we identify an intermediate gapless spin liquid
phase between a metallic phase at weak coupling and Mott insulating dimer phase
at strong interaction, which has one gapless spin mode and algebraic spin-spin
correlations but exponential decay scalar chiral-chiral correlations. Upon
light doping the gapless spin liquid, the system exhibits power-law
charge-density-wave (CDW) correlations but short-range single-particle,
spin-spin, and chiral-chiral correlations. Similar to CDW correlations, the
superconducting correlations are also quasi-long-ranged but oscillate in sign
as a function of distance, which is consistent with the striped pair-density
wave. When further doping the gapless spin liquid phase or doping the dimer
order phase, another phase takes over, which has similar CDW correlations but
all other correlations decay exponentially.",2103.07998v1
2012-07-26,Detecting binary neutron star systems with spin in advanced gravitational-wave detectors,"The detection of gravitational waves from binary neutron stars is a major
goal of the gravitational-wave observatories Advanced LIGO and Advanced Virgo.
Previous searches for binary neutron stars with LIGO and Virgo neglected the
component stars' angular momentum (spin). We demonstrate that neglecting spin
in matched-filter searches causes advanced detectors to lose more than 3% of
the possible signal-to-noise ratio for 59% (6%) of sources, assuming that
neutron star dimensionless spins, $c\mathbf{J}/GM^2$, are uniformly distributed
with magnitudes between 0 and 0.4 (0.05) and that the neutron stars have
isotropically distributed spin orientations. We present a new method for
constructing template banks for gravitational wave searches for systems with
spin. We present a new metric in a parameter space in which the template
placement metric is globally flat. This new method can create template banks of
signals with non-zero spins that are (anti-)aligned with the orbital angular
momentum. We show that this search loses more than 3% of the maximium
signal-to-noise for only 9% (0.2%) of BNS sources with dimensionless spins
between 0 and 0.4 (0.05) and isotropic spin orientations. Use of this template
bank will prevent selection bias in gravitational-wave searches and allow a
more accurate exploration of the distribution of spins in binary neutron stars.",1207.6406v2
2018-04-22,Spontaneous spinning of a rattleback placed on vibrating platform,"The spontaneous spinning of a rattleback placed on a vibrating platform is
investigated. The rattleback is a toy with some curious properties. When placed
on a surface with reasonable friction, the rattleback has a preferred direction
of spin. If rotated anti to it, longitudinal vibrations are set up and spin
direction is reversed.
  In this paper, the dynamics of a rattleback placed on a sinusoidally
vibrating platform are simulated. We can expect base vibrations to excite the
pitch motion of the rattleback, which, because of the coupling between pitch
and spin motion, should cause the rattleback to spin. Results are presented
which show that this indeed is the case- the rattleback has a mono-peak spin
resonance with respect to base vibrations. The rattleback, thus, transduces
translating vibrations into continuous rotary motion and, therefore, is ideal
for applications in Energy harvesting and Vibration sensing.
  The dynamic response of the rattleback was found to be composed of two
principal frequencies that appeared in the pitch and rolling motions. One of
the frequencies was found to have a large coupling with the spin of the
rattleback. Spin resonance was found to occur when the base oscillatory
frequency was twice the value of the coupled frequency. A linearized model is
developed which can predict the values of the two frequencies accurately and
analytical expressions for the same in terms of the parameters of the
rattleback have been derived. The analysis, thus, forms an effective and easy
method for obtaining the spin resonant frequency of a given rattleback.
  Novel ideas for applications utilizing the phenomenon of spin resonance, for
example, an energy harvester composed of a magnetized rattleback surrounded by
ferromagnetic walls and a small scale vibration sensor comprising an array of
several magnetized rattlebacks, are included.",1804.08163v1
2010-06-18,"Corotational Instability, Magnetic Resonances and Global Inertial-Acoustic Oscillations in Magnetized Black-Hole Accretion Discs","Low-order, non-axisymmetric p-modes (also referred as inertial-acoustic
modes) trapped in the inner-most region of hydrodynamic accretion discs around
black holes, are plausible candidates for high-frequency quasi-periodic
oscillations (QPOs) observed in a number of accreting black-hole systems. These
modes are subject to global instabilities due to wave absorption at the
corotation resonance (where the wave pattern frequency $\omega/m$ equals the
disc rotation rate $\Omega$), when the fluid vortensity,
$\zeta=\kappa^2/(2\Omega\Sigma)$ (where $\kappa$ and $\Sigma$ are the radial
epicyclic frequency and disc surface density, respectively), has a positive
gradient. We investigate the effects of disc magnetic fields on the wave
absorption at corotation and the related wave super-reflection of the
corotation barrier, and on the overstability of disc p-modes. For discs with a
pure toroidal field, the corotation resonance is split into two magnetic
resonances, where the wave frequency in the corotating frame of the fluid,
$\tomega=\omega-m\Omega$, matches the slow magnetosonic wave frequency.
Significant wave energy/angular momentum absorption occurs at both magnetic
resonances, but with opposite signs. The combined effect of the two magnetic
resonances is to reduce the super-reflection and the growth rate of the
overstable p-modes. We show that even a subthermal toroidal field may suppress
the overstability of hydrodynamic (B=0) p-modes. For accretion discs with mixed
(toroidal and vertical) magnetic fields, two additional Alfven resonances
appear, where $\tomega$ matches the local Alfven wave frequency. They further
reduce the growth rate of p-modes. Our results suggest that in order for the
non-axisymmetric p-modes to be a viable candidate for the observed
high-frequency QPOs, the disc magnetic field must be appreciably subthermal, or
other mode excitation mechanisms are at work.",1006.3763v3
2005-11-02,"Effects of strain, electric, and magnetic fields on lateral electron spin transport in semiconductor epilayers","We construct a spin-drift-diffusion model to describe spin-polarized electron
transport in zincblende semiconductors in the presence of magnetic fields,
electric fields, and off-diagonal strain. We present predictions of the model
for geometries that correspond to optical spin injection from the absorption of
circularly polarized light, and for geometries that correspond to electrical
spin injection from ferromagnetic contacts. Starting with the Keldysh Green's
function description for a system driven out of equilibrium, we construct a
semiclassical kinetic theory of electron spin transport in strained
semiconductors in the presence of electric and magnetic fields. From this
kinetic theory we derive spin-drift-diffusion equations for the components of
the spin density matrix for the specific case of spatially uniform fields and
uniform electron density. We solve the spin-drift-diffusion equations
numerically and compare the resulting images with scanning Kerr microscopy data
of spin-polarized conduction electrons flowing laterally in bulk epilayers of
n-type GaAs. The spin-drift-diffusion model accurately describes the
experimental observations. We contrast the properties of electron spin
precession resulting from magnetic and strain fields. Spin-strain coupling
depends linearly on electron wave vector and spin-magnetic field coupling is
independent of electron wave vector. As a result, spatial coherence of
precessing spin flows is better maintained with strain than with magnetic
fields, and the spatial period of spin precession is independent of the applied
electrical bias in strained structures whereas it is strongly bias dependent
for the case of applied magnetic fields.",0511038v1
2011-07-06,Addressing the spin question in gravitational-wave searches: Waveform templates for inspiralling compact binaries with nonprecessing spins,"This paper presents a post-Newtonian (PN) template family of gravitational
waveforms from inspiralling compact binaries with non-precessing spins, where
the spin effects are described by a single ""reduced-spin"" parameter. This
template family, which reparametrizes all the spin-dependent PN terms in terms
of the leading-order (1.5PN) spin-orbit coupling term \emph{in an approximate
way}, has very high overlaps (fitting factor > 0.99) with non-precessing
binaries with arbitrary mass ratios and spins. We also show that this template
family is ""effectual"" for the detection of a significant fraction of generic
spinning binaries in the comparable-mass regime (m_2/m_1 <~ 10), providing an
attractive and feasible way of searching for gravitational waves (GWs) from
spinning low-mass binaries. We also show that the secular (non-oscillatory)
spin-dependent effects in the phase evolution (which are taken into account by
the non-precessing templates) are more important than the oscillatory effects
of precession in the comparable-mass (m_1 ~= m_2) regime. Hence the
effectualness of non-spinning templates is particularly poor in this case, as
compared to non-precessing-spin templates. For the case of binary neutron stars
observable by Advanced LIGO, even moderate spins (L . S/m^2 ~= 0.015 - 0.1)
will cause considerable mismatches (~ 3% - 25%) with non-spinning templates.
This is contrary to the expectation that neutron-star spins may not be relevant
for GW detection.",1107.1267v2
2018-11-06,Spin of LIGO/VIRGO merging black holes as the result of binary evolution,"Recently discovered bursts of gravitational waves provide a good opportunity
to verify the current view on the evolution of close binary stars. Modern
population synthesis computer programs help to study this evolution from two
main sequence stars up to the formation of compact remnants. To calculate the
evolution of predecessors of black hole (BH) mergers we used the `Scenario
Machine' code. The scenario modelling allowed to describe the evolution of
systems for which the final stage is a BH+BH merger and showed the plausibility
of modern evolutionary scenarios for binary stars and population synthesis
models based on it. We discuss possible values of spins in BH mergers, and give
arguments in favour of different values of spins of BH components in BH mergers
(low spin + low spin, low spin + high spin, high spin + high spin). We predict
that $\geq 50\%$ BH mergers originated through isolated binary evolution should
possess spins of both BHs close to zero (low spin + low spin). Up to
$\approx$10\% of BH mergers are able to consist of two BHs with spins close to
one (high spin + high spin), predecessors of such binaries could be sources of
two gamma ray bursts. The BH with the spin close to one could be formed as the
result of the merger of two BHs formed via the collapse of a fast rotating star
accompanied with a long gamma ray burst and/or a gravitational wave burst with
smaller power in comparison with the merger of two BH remnants of binary
components.",1811.02294v1
2012-11-05,"Class of variational ansaetze for the ""spin-incoherent"" ground-state of a Luttinger liquid coupled to a spin bath","Interacting one-dimensional electron systems are generally referred to as
""Luttinger liquids"", after the effective low-energy theory in which spin and
charge behave as separate degrees of freedom with independent energy scales.
The ""spin-incoherent Luttinger liquid"" describes a finite-temperature regime
that is realized when the temperature is very small relative to the Fermi
energy, but larger than the characteristic spin energy scale. Similar physics
can take place in the ground-state, when a Luttinger Liquid is coupled to a
spin bath, which effectively introduces a ""spin temperature"" through its
entanglement with the spin degree of freedom. We show that the spin-incoherent
state can be written as a factorized wave-function, with a spin wave-function
that can be described within a valence bond formalism. This enables us to
calculate exact expressions for the momentum distribution function and the
entanglement entropy. This picture holds not only for two antiferromagnetically
coupled t-J chains, but also for the t-J-Kondo chain with strongly interacting
conduction electrons. We argue that this theory is quite universal and may
describe a family of problems that could be dubbed ""spin-incoherent"".",1211.0982v1
2017-09-20,Spin-rotation mode in a quantum Hall ferromagnet,"A spin-rotation mode emerging in a quantum Hall ferromagnet due to laser
pulse excitation is studied. This state, macroscopically representing a
rotation of the entire electron spin-system to a certain angle, is not
microscopically equivalent to a coherent turn of all spins as a single-whole
and is presented in the form of a combination of eigen quantum states
corresponding to all possible S_z spin numbers. The motion of the macroscopic
quantum state is studied microscopically by solving a non-stationary
Schroedinger equation and by means of a kinetic approach where damping of the
spin-rotation mode is related to an elementary process, namely, transformation
of a `Goldstone spin exciton' to a `spin-wave exciton'. The system exhibits a
spin stochastizationa mechanism (determined by spatial fluctuations of the
Land'e g-factor) ensuring damping, transverse spin relaxation, but irrelevant
to decay of spin-wave excitons and thus not involving longitudinal relaxation,
i.e., recovery of the S_z number to its equilibrium value.",1709.06811v2
2013-10-10,Spin entanglement and nonlocality of multifermion systems,"Spin density matrices of the system, containing arbitrary even number N of
indistinguishable fermions with spin S = 1/2, described by antisymmetric wave
function, have been calculated. The indistinguishability and the Pauli
principles are proved to determine uniquely spin states, spin correlations and
entanglement of fermion spin states. Increase of the particle number in the
multifermion system reduces the spin correlation in any pair of fermions. The
fully entangled system of N electrons are shown to be composed by pairs with
nonentangled spin states that is the incoherent superposition of the singlet
and triplet states. Any large system of N fermions, such as electrons with spin
S = 1/2, the spin state of any particle are shown to be entangled with the
other part of the system containing N-1 particle. However, the spin state of
this electron is not entangled with any other particle, and spin state of any
electron pair is not entangled. These properties of spin states manifest in the
Einstein-Podolsky-Rosen as confirmation or violation of the Bell inequalities
indicating the presence of non-local quantum spin correlations.",1310.2863v3
2018-01-29,Isoscalar and Isovector spin response in $sd-$ shell nuclei,"The spin magnetic dipole transitions and the neutron-proton spin-spin
correlations in $sd-$shell even-even nuclei with $N=Z$ are investigated using
shell model wave functions taking into accout enhanced isoscalar (IS)
spin-triplet pairing as well as the effective spin operators. It was shown that
the IS pairing and the effective spin operators gives a large quenching effect
on the IV spin transitions to be consistent with observed data by $(p,p')$
experiments. On the other hand, the observed IS spin strength show much smaller
quenching effect than expected by the calculated results. The IS pairing gives
a substantial quenching effect on the spin magnetic dipole transitions,
especially on the isovector (IV) ones. Consequently, an enhanced isoscalar
spin-triplet pairing interaction enlarges the proton-neutron spin-spin
correlation deduced from the difference between the isoscalar (IS) and the IV
sum rule strengths. The beta-decay rates and the IS magnetic moments of
$sd-$shell are also examined in terms of the IS pairing as well as the
effective spin operators.",1801.10039v1
2018-11-23,Self-stabilizing exchange-mediated spin transport,"Long-range spin transport in magnetic systems can be achieved by means of
exchange-mediated spin textures with robust topological winding -- a phenomenon
referred to as spin superfluidity. Its experimental signatures have been
discussed in antiferromagnets which are nearly free of dipolar interaction.
However, in ferromagnets, which possess non-negligible dipole fields,
realization of such spin transport has remained a challenge. Using
micromagnetic simulations, we investigate coherent exchange-mediated spin
transport in extended thin ferromagnetic films. We uncover a two-fluid state,
in which the long-range spin transport by spin textures co-exists with spin
waves, as well as a soliton-screened spin transport regime at high spin
injection biases. Both states are associated with distinct spin texture
reconstructions near the spin injection region and sustain spin transport over
large distances.",1811.09369v2
2000-06-20,Microscopic Theory of Dipole-Exchange Spin Waves in Ferromagnetic Films: Linear and Nonlinear Processes,"The linear and nonlinear processes in ferromagnetic films at low temperatures
T<< Tc are studied in a microscopic theory. Both the long-range magnetic
dipole-dipole and the Heisenberg exchange interactions to nearest and
next-nearest neighbors are included. The results obtained for the linearized
spin-wave spectrum are compared with previous macroscopic theories. For
ultrathin films (or for large wave vectors) the microscopic theory provides
important corrections. The nonlinear dynamics of the spin waves are studied
through a finite-temperature perturbation theory based on Feynman diagrams. We
obtain explicit results for the energy shift and damping (or reciprocal
lifetime) of the dipole-exchange spin waves due to all possible three-magnon
and four-magnon processes involving combinations of the surface and quantized
bulk spin waves at low temperatures. To investigate different dipole
interaction strengths (relative to the exchange) numerical results are
presented using parameters for Fe, EuO, and GdCl3.",0006308v1
2000-06-29,"Coexistence of charge density waves, bond order waves and spin density waves in quasi-one dimensional charge transfer salts","Charge, spin, as well as lattice instabilities are investigated in isolated
or weakly coupled chains of correlated electrons at quarter-filling. Our
analysis is based on extended Hubbard models including nearest neighbor
repulsion and Peierls coupling to lattice degrees of freedom. While treating
the electronic quantum fluctuations exactly, the lattice structure is optimized
self-consistently. We show that, generically, isolated chains undergo
instabilities towards coexisting charge density waves (CDW) and bond order
waves (BOW) insulating spin-gapped phases. The spin and charge gaps of the
BOW-CDW phase are computed. In the presence of an interchain magnetic coupling
spin density waves phases including a CDW or a BOW component are also found.
Our results are discussed in the context of insulating charge transfer salts.",0006460v2
2006-06-09,Spin wave dynamics and the determination of intrinsic Gilbert damping in locally-excited Permalloy thin films,"Time-resolved scanning Kerr effect microscopy has been used to study
magnetization dynamics in Permalloy thin films excited by transient magnetic
pulses generated by a micrometer-scale transmission line structure. The results
are consistent with magnetostatic spin wave theory and are supported by
micromagnetic simulations. Magnetostatic volume and surface spin waves are
measured for the same specimen using different bias field orientations and can
be accurately calculated by k-space integrations over all excited plane wave
components. A single damping constant of Gilbert form is sufficient to describe
both scenarios. The nonuniform pulsed field plays a key role in the spin wave
dynamics, with its Fourier transform serving as a weighting function for the
participating modes. The intrinsic Gilbert damping parameter $\alpha$ is most
conveniently measured when the spin waves are effectively stationary.",0606235v3
2007-01-08,Effect of spatial confinement on spin-wave spectrum: Low temperature deviation from Bloch T3/2 law in Co nanoparticles,"We present the study on Bloch T3/2 law and its applicability in ferromagnetic
cobalt nanoparticles with sizes 25 and 38 nm. Bloch has derived the T3/2 law by
assuming long wave-length spin-waves to be excited at low temperatures. But, in
nanoparticles the wavelength of the spin wave is confined by the size of the
magnetic particle leading to the gap in the spin-wave energy spectrum. The
experimental observation leads to the conclusion that Bloch law is valid at
temperatures higher than the spin-wave energy gap. However, it is not
applicable at low enough temperatures, where the energy gap becomes prominent.
We have demonstrated that a theory recently developed by us [Mandal et al.,
Europhys. Lett. 75, 618 (2006)] explains the variation of magnetization with
temperature accurately. In addition, the hysteresis properties of these cobalt
nanoparticles are also presented here.",0701152v1
2008-08-10,Formation of guided spin-wave bullets in ferrimagnetic film stripes,"The formation of quasi-2D nonlinear spin-wave eigenmodes in longitudinally
magnetized stripes of a ferrimagnetic film, so-called guided spin-wave bullets,
was experimentally observed by using time- and space-resolved Brillouin light
scattering spectroscopy and confirmed by numerical simulation. They represent
stable spin-wave packets propagating along a waveguide structure, for which
both transversal instability and interaction with the side edges of the
waveguide are important. The experiments and the numerical simulation of the
evolution of the spin-wave excitations show that the shape of the formed
packets and their behavior are strongly influenced by the confinement
conditions. The discovery of these modes demonstrates the existence of
quasi-stable nonlinear solutions in the transition regime between
one-dimensional and two-dimensional wave packet propagation.",0808.1399v1
2009-03-21,Scattering of surface and volume spin waves in a magnonic crystal,"The operational characteristics of a magnonic crystal, which was fabricated
as an array of shallow grooves etched on a surface of a magnetic film, were
compared for magnetostatic surface spin waves and backward volume magnetostatic
spin waves. In both cases the formation of rejection frequency bands was
studied as a function of the grooves depth. It has been found that the
rejection of the volume wave is considerably larger than of the surface one.
The influences of the nonreciprocity of the surface spin waves as well as of
the scattering of the lowest volume spin-wave mode into higher thickness volume
modes on the rejection efficiency are discussed.",0903.3686v1
2014-07-25,Transverse spin and momentum in two-wave interference,"We analyze the interference field formed by two electromagnetic plane waves
(with the same frequency but different wave vectors), and find that such field
reveals a rich and highly non-trivial structure of the local momentum and spin
densities. Despite the seemingly-planar and extensively-studied character of
the two-wave system, we find that it possesses a transverse (out-of-plane)
helicity-independent spin density, and also a transverse polarization-dependent
momentum density with unusual physical properties. The polarization-dependent
transverse momentum represents the so-called Belinfante spin momentum, which
does not exert the usual optical pressure and it is considered as `virtual' in
field theory. We perform analytical estimations and exact numerical simulations
of the interaction of the two-wave field with probe Mie particles. The results
of these calculations clearly indicate the straightforward detectability of the
unusual spin and momentum properties in the two-wave field and strongly
motivate their future experimental verifications.",1407.6786v2
2015-03-06,Standing spin wave mode in RFIM at T=0: Patterns and nonequilibrium phases,"The dynamical responses of random field Ising model at zero temperature,
driven by standing magnetic field wave, is studied by Monte Carlo simulation in
two dimensions. The three different kinds of distribution of quenched random
field are used here, uniform, bimodal and Gaussian. In all cases, three
distinct dynamical phases were observed, namely, the pinned, structured and
random. In the pinned phase no spin flip is observed. In the structured phase
standing spin wave modes are observed. The random phase is shown no regular
pattern. For a fixed value of the amplitude of the standing magnetic field
wave, in the region of small quenched field, the system remains in a pinned
phase. In the intermediate range of values of random field, a standing spin
wave mode (structured phase) is observed. The regular pattern of this spin wave
mode disappears for higher values of random field yielding a random phase. The
comprehensive phase baundaries are drawn in all three cases. The boundary of
pinned phase are analytically calculated for uniform and bimodal types of
quenched random fields.",1503.01861v2
2019-11-12,Parametric generation of propagating spin-waves in ultra thin yttrium iron garnet waveguides,"We present the experimental demonstration of the parallel parametric
generation of spin-waves in a microscaled yttrium iron garnet waveguide with
nanoscale thickness. Using Brillouin light scattering microscopy, we observe
the excitation of the first and second waveguide modes generated by a stripline
microwave pumping source. Micromagnetic simulations reveal the wave vector of
the parametrically generated spin-waves. Based on analytical calculations,
which are in excellent agreement with our experiments and simulations, we prove
that the spin-wave radiation losses are the determinative term of the
parametric instability threshold in this miniaturized system. The used method
enables the direct excitation and amplification of nanometer spin-waves
dominated by exchange interactions. Our results pave the way for integrated
magnonics based on insulating nano-magnets.",1911.04926v2
2021-11-03,Efficient geometrical control of spin waves in microscopic YIG waveguides,"We study experimentally and by micromagnetic simulations the propagation of
spin waves in 100-nm thick YIG waveguides, where the width linearly decreases
from 2 to 0.5 micrometers over a transition region with varying length between
2.5 and 10 micrometers. We show that this geometry results in a down-conversion
of the wavelength, enabling efficient generation of waves with wavelengths down
to 350 nm. We also find that this geometry leads to a modification of the group
velocity, allowing for almost-dispersionless propagation of spin-wave pulses.
Moreover, we demonstrate that the influence of energy concentration outweighs
that of damping in these YIG waveguides, resulting in an overall increase of
the spin-wave intensity during propagation in the transition region. These
findings can be utilized to improve the efficiency and functionality of
magnonic devices which use spin waves as an information carrier.",2111.02236v1
2022-08-23,Reversal of nanomagnets by propagating magnons in ferrimagnetic yttrium iron garnet enabling nonvolatile magnon memory,"Despite the unprecedented downscaling of CMOS integrated circuits,
memory-intensive machine learning and artificial intelligence applications are
limited by data conversion between memory and processor. There is a challenging
quest for novel approaches to overcome this so-called von Neumann bottleneck.
Magnons are the quanta of spin waves and transport angular momenta through
magnets. They enable power-efficient computation without charge flow and would
solve the conversion problem if spin wave amplitudes could be stored directly
in a magnetic memory cell. Here, we report the reversal of ferromagnetic
nanostripes by spin waves which propagate through an underlying spin-wave bus
made from yttrium iron garnet. Thereby, the charge-free angular momentum flow
is stored after transmission over a macroscopic distance. We show that spin
waves can reverse large arrays of ferromagnetic stripes at a strikingly small
power level of nW. Combined with the already existing wave logic, our discovery
is path-breaking for the new era of magnonics-based in-memory computation and
beyond von Neumann computer architectures.",2208.10923v1
2022-09-14,Generation of Spin-Wave Pulses by Inverse Design,"The development of fast magnonic information processing nanodevices requires
operating with short spin-wave pulses, but, the shorter the pulses, the more
affected they are by information loss due to broadening and dispersion. The
capability of engineering spin-wave pulses and controlling their propagation
could solve this problem. Here, we provide a method to generate linear
spin-wave pulses with a desired spatial-temporal profile in magnonic waveguides
based on inverse design. As relevant examples, we theoretically predict that
both rectangular and self-compressing spin-wave pulses can be generated in
state-of-the-art waveguides with fidelities >96% using narrow stripline
antennas. The method requires minimal computational overhead and is universal,
i.e., it applies to arbitrary targeted pulse shapes, type of waves (exchange or
dipolar), waveguide materials, and waveguide geometries. It can also be
extended to more complex magnonic structures. Our results could lead to the
utilization of large-scale magnonic circuits for classical and quantum
information processing.",2209.06608v1
2022-10-26,Nonreciprocal collective magnetostatic wave modes in geometrically asymmetric bilayer structure with nonmagnetic spacer,"Nonreciprocity, i.e. inequivalence in amplitudes and frequencies of spin
waves propagating in opposite directions, is a key property underlying
functionality in prospective magnonic devices. Here we demonstrate
experimentally and theoretically a simple approach to induce frequency
nonreciprocity in a magnetostatically coupled ferromagnetic bilayer structure
with a nonmagnetic spacer by its geometrical asymmetry. Using Brillouin light
scattering, we show the formation of two collective spin wave modes in
Fe$_{81}$Ga$_{19}$/Cu/Fe$_{81}$Ga$_{19}$ structure with different thicknesses
of ferromagnetic layers. Experimental reconstruction and theoretical modeling
of the dispersions of acoustic and optical collective spin wave modes reveal
that both possess nonreciprocity reaching several percent at the wavenumber of
$22~\cdot~10^4$ rad cm$^{-1}$. The analysis demonstrates that the shift of the
amplitudes of counter-propagating coupled modes towards either of the layers is
responsible for the nonreciprocity because of the pronounced dependence of spin
wave frequency on the layers thickness. The proposed approach enables the
design of multilayered ferromagnetic structures with a given spin wave
dispersion for magnonic logic gates.",2210.14882v2
2023-06-28,Dissipative Spin-wave Diode and Nonreciprocal Magnonic Amplifier,"We propose an experimentally feasible dissipative spin-wave diode comprising
two magnetic layers coupled via a non-magnetic spacer. We theoretically
demonstrate that the spacer mediates not only coherent interactions but also
dissipative coupling. Interestingly, an appropriately engineered dissipation
engenders a nonreciprocal device response, facilitating the realization of a
spin-wave diode. This diode permits wave propagation in one direction alone,
given that the coherent Dzyaloshinskii- Moriya (DM) interaction is balanced
with the dissipative coupling. The polarity of the diode is determined by the
sign of the DM interaction. Furthermore, we show that when the magnetic layers
undergo incoherent pumping, the device operates as a unidirectional spin-wave
amplifier. The amplifier gain is augmented by cascading multiple magnetic
bilayers. By extending our model to a one-dimensional ring structure, we
establish a connection between the physics of spin-wave amplification and
non-Hermitian topology. Our proposal opens up a new avenue for harnessing
inherent dissipation in spintronic applications.",2306.15916v1
2020-03-02,Shortcut to geostrophy in wave-driven rotating turbulence: the quartetic instability,"We report on laboratory experiments of wave-driven rotating turbulence. A set
of wavemakers produces inertial-wave beams that interact nonlinearly in the
central region of a water tank mounted on a rotating platform. The forcing thus
injects energy into inertial waves only. For moderate forcing amplitude, part
of the energy of the forced inertial waves is transferred to subharmonic waves,
through a standard triadic resonance instability. This first step is broadly in
line with the theory of weak turbulence. Surprisingly however, stronger forcing
does not lead to an inertial-wave turbulence regime. Instead, most of the
kinetic energy condenses into a vertically invariant geostrophic flow, even
though the latter is unforced. We show that resonant quartets of inertial waves
can trigger an instability -- the ``quartetic instability'' -- that leads to
such spontaneous emergence of geostrophy. In the present experiment, this
instability sets in as a secondary instability of the classical triadic
instability.",2003.01177v1
2021-04-29,Selective mode conversion and rainbow trapping via graded elastic waveguides,"We experimentally achieve wave mode conversion and rainbow trapping in an
elastic waveguide loaded with an array of resonators. Rainbow trapping is a
phenomenon that induces wave confinement as a result of a spatial variation of
the wave velocity, here promoted by gently varying the length of consecutive
resonators. By breaking the geometrical symmetry of the waveguide, we combine
the wave speed reduction with a reflection mechanism that mode-converts
flexural waves impinging on the array into torsional waves travelling along
opposite directions. The framework presented herein may open opportunities in
the context of wave manipulation through the realization of structural
components with concurrent wave conversion and energy trapping capabilities.",2104.14394v2
2019-07-09,Forced three-wave interactions of capillary-gravity surface waves,"{Three-wave resonant interactions constitute an essential nonlinear mechanism
coupling capillary surface waves. In a previous work, Haudin et al. [Phys. Rev
E 93, 043110 (2016)], we have characterized experimentally the generation by
this mechanism of a daughter wave, whose amplitude saturates due to the viscous
dissipation. Here, we show experimentally the generation of a daughter wave
verifying the resonant conditions, but not the dispersion relation.} By
modeling the response of the free surface at the lowest nonlinear order, we
explain this observation as a forced interaction. {The bandwidth of the linear
transfer function of the free surface is indeed increased by the significant
viscous dissipation.} The observation of free surface excitations not following
the linear dispersion relation then becomes possible. This forced three-wave
interaction mechanism could have important consequences for wave turbulence in
experimental or natural systems with non negligible dissipation.",1907.04365v1
2024-01-08,Generation of interfacial waves by rotating magnetic fields,"Interfacial waves arising in a two-phase swirling flow driven by a
low-frequency rotating magnetic field (RMF) are studied. At low RMF
frequencies, of the order of 1-10 Hz, the oscillatory part of the induced
Lorenz force becomes comparable to the time-averaged one, and cannot be
neglected. In particular, when free surfaces or two-liquid stably stratified
systems are subject to a low-frequency RMF, induced pressure variations
necessarily excite free-surface/interfacial waves, which can improve mass
transfer in different metallurgical processes. In this paper, we formulate a
linear wave model and derive explicit analytical solutions predicting
RMF-driven wave patterns that closely resemble hyperbolic paraboloids. These
theoretical predictions are validated against experiments based on a
non-intrusive acoustic measurement technique, which measures liquid-liquid
interface elevations in a two-phase KOH-GaInSn stably stratified system. A good
quantitative agreement is found for non-resonant wave responses in the vicinity
of the fundamental resonance frequency. The experiments reveal the additional
excitation of several higher harmonics superimposing the fundamental wave
oscillation, which are visible even in the linear wave regime.",2401.04045v1
2016-02-28,Scattering of Waves by Impurities in Precompressed Granular Chains,"We study scattering of waves by impurities in strongly precompressed granular
chains. We explore the linear scattering of plane waves and identify a
closed-form expression for the reflection and transmission coefficients for the
scattering of the waves from both a single impurity and a double impurity. For
single-impurity chains, we show that, within the transmission band of the host
granular chain, high-frequency waves are strongly attenuated (such that the
transmission coefficient vanishes as the wavenumber $k\rightarrow \pm\pi$),
whereas low-frequency waves are well-transmitted through the impurity. For
double-impurity chains, we identify a resonance --- enabling full transmission
at a particular frequency --- in a manner that is analogous to the
Ramsauer--Townsend (RT) resonance from quantum physics. We also demonstrate
that one can tune the frequency of the RT resonance to any value in the pass
band of the host chain. We corroborate our theoretical predictions both
numerically and experimentally, and we directly observe complete transmission
for frequencies close to the RT resonance frequency. Finally, we show how this
RT resonance can lead to the existence of reflectionless modes even in granular
chains (including disordered ones) with multiple double impurities.",1602.08651v2
2020-12-23,Theoretical description of chirping waves using phase-space waterbags,"The guiding centre dynamics of fast particles can alter the behaviour of
energetic particle driven modes with chirping frequencies. In this paper, the
applicability of an earlier trapped/passing locus model [H. Hezaveh et al 2017
Nucl. Fusion 57 126010] has been extended to regimes where the wave trapping
region can expand and trap ambient particles. This extension allows the study
of waves with up-ward and down-ward frequency chirping across the full range of
energetic particle orbits. Under the adiabatic approximation, the phase-space
of energetic particles is analysed by a Lagrangian contour approach where the
islands are discretised using phase-space waterbags. In order to resolve the
dynamics during the fast formation of phase-space islands and find an
appropriate initialisation for the system, full-scale modelling is implemented
using the bump-on-tail (BOT) code. In addition to investigating the evolution
of chirping waves with deepening potentials in a single resonance, we choose
specific pitch-angle ranges in which higher resonances can have a relatively
considerable contribution to the wave-particle interaction. Hence, the model is
also solved in a double-resonance scenario where we report on the significant
modifications to the behaviour of the chirping waves due to the $2^{\text{nd}}$
resonance. The model presented in this paper gives a comprehensive 1D paradigm
of long range frequency chirping signals observed in experiments with both
up-ward and down-ward chirping and multiple resonances.",2012.12504v1
2022-06-16,Electron spin resonance and collective excitations in magic-angle twisted bilayer graphene,"In a strongly correlated system, collective excitations contain key
information regarding the electronic order of the underlying ground state. An
abundance of collective modes in the spin and valley isospin channels of
magic-angle graphene moir\'e bands has been alluded to by a series of recent
experiments. However, direct observation of collective excitations has remained
elusive due to the lack of a spin probe. In this work, we use a
resistively-detected electron spin resonance technique to look for low-energy
collective excitations in magic-angle twisted bilayer graphene. We report
direct observation of collective modes in the form of microwave-induced
resonance near half filling of the moir\'e flatbands. The frequency-magnetic
field dependence of these resonance modes sheds light onto the nature of
intervalley spin coupling, allowing us to extract parameters such as
intervalley exchange interaction and spin stiffness. Two independent
observations testify that the generation and detection of the microwave
resonance relies on the strong correlation within the flat moir\'e energy band.
First, the onset of robust resonance response coincides with the spontaneous
flavor polarization at half moir\'e filling, and remains absent in the density
range where the underlying Fermi surface is isospin unpolarized. Second, we
performed the same resonance measurement on graphene monolayer and bilayer
samples, including twisted bilayer with a large twist angle, where flatband
physics is absent. We observe no indication of resonance response in these
samples across a large range of carrier density, microwave frequency and power.
A natural explanation is that the resonance response near the magic angle
originates from ""Dirac revivals"" and the resulting isospin order.",2206.08354v2
2004-11-09,Single-shot read-out of an individual electron spin in a quantum dot,"Spin is a fundamental property of all elementary particles. Classically it
can be viewed as a tiny magnetic moment, but a measurement of an electron spin
along the direction of an external magnetic field can have only two outcomes:
parallel or anti-parallel to the field. This discreteness reflects the quantum
mechanical nature of spin. Ensembles of many spins have found diverse
applications ranging from magnetic resonance imaging to magneto-electronic
devices, while individual spins are considered as carriers for quantum
information. Read-out of single spin states has been achieved using optical
techniques, and is within reach of magnetic resonance force microscopy.
However, electrical read-out of single spins has so far remained elusive. Here,
we demonstrate electrical single-shot measurement of the state of an individual
electron spin in a semiconductor quantum dot. We use spin-to-charge conversion
of a single electron confined in the dot, and detect the single-electron charge
using a quantum point contact; the spin measurement visibility is ~65%.
Furthermore, we observe very long single-spin energy relaxation times (up to
0.85 ms at a magnetic field of 8 Tesla), which are encouraging for the use of
electron spins as carriers of quantum information.",0411232v2
2011-03-02,Quantum control of proximal spins using nanoscale magnetic resonance imaging,"Quantum control of individual spins in condensed matter systems is an
emerging field with wide-ranging applications in spintronics, quantum
computation, and sensitive magnetometry. Recent experiments have demonstrated
the ability to address and manipulate single electron spins through either
optical or electrical techniques. However, it is a challenge to extend
individual spin control to nanoscale multi-electron systems, as individual
spins are often irresolvable with existing methods. Here we demonstrate that
coherent individual spin control can be achieved with few-nm resolution for
proximal electron spins by performing single-spin magnetic resonance imaging
(MRI), which is realized via a scanning magnetic field gradient that is both
strong enough to achieve nanometric spatial resolution and sufficiently stable
for coherent spin manipulations. We apply this scanning field-gradient MRI
technique to electronic spins in nitrogen-vacancy (NV) centers in diamond and
achieve nanometric resolution in imaging, characterization, and manipulation of
individual spins. For NV centers, our results in individual spin control
demonstrate an improvement of nearly two orders of magnitude in spatial
resolution compared to conventional optical diffraction-limited techniques.
This scanning-field-gradient microscope enables a wide range of applications
including materials characterization, spin entanglement, and nanoscale
magnetometry.",1103.0546v1
2015-05-26,Vector magnetometry based on S=3/2 electronic spins,"Electronic spin systems with S>1/2 provide an efficient method for DC vector
magnetometry, since the conventional electron spin resonance spectra at a given
magnetic field reflect not only the field strength but also orientation in the
presence of strong spin-spin interactions. S=1 spins, e.g. the nitrogen-vacancy
centers in diamond, have been intensively investigated for such a purpose. In
this report, we compare S=1 and S=3/2 spins, and discuss how one can apply
general principles for the use of high spin systems as a vector magnetometer to
the S=3/2 spin systems. We find analytical solutions which allow a
reconstruction of the magnetic field strength and polar angle using the
observed resonance transitions if an uniaxial symmetry exists for the spin-spin
interaction as in S=1 systems. We also find that an ambiguity of determining
the field parameters may arise due to the unique properties of S=3/2 systems,
and present solutions for it utilizing additional transitions in the low-field
region. The electronic spins of the silicon vacancy in silicon carbide will be
introduced as a model for the S=3/2 DC vector magnetometer and the practical
usage of it, including the magic-angle spinning type method, will be presented
too.",1505.06914v2
2016-03-03,Non-equilibrium charge and spin transport in SFS point contacts,"The conventional Josephson effect may be modified by introducing spin-active
scattering in the interface-layer of the junction. Here, we discuss a Josephson
junction consisting of two s-wave superconducting leads coupled over a
classical spin that precesses with the Larmor frequency due to an external
magnetic field. This magnetically active interface results in a time-dependent
boundary condition with different tunnelling amplitudes for spin-up and -down
quasiparticles and where the precession produces spin-flip scattering
processes. As a result, the Andreev states develop sidebands and a
non-equilibrium population that depend on the details of the spin precession.
The Andreev states carry a steady-state Josephson charge current and a
time-dependent spin current, whose current-phase relations could be used for
characterising the precessing spin. The spin current is supported by
spin-triplet correlations induced by the spin precession and creates a
feed-back effect on the classical spin in the form of a torque that shifts the
precession frequency.
  By applying a bias voltage, the Josephson frequency adds another complexity
to the situation and may create resonances together with the Larmor frequency.
These Shapiro resonances are manifested as torques and are, under suitable
conditions, able to reverse the direction of the classical spin in
sub-nanosecond time. Another characteristic feature is the subharmonic gap
structure in the dc charge current displaying an even-odd effect that is
attributable to precession-assisted multiple Andreev reflections.",1603.01299v1
2004-06-22,"Spin susceptibilities, spin densities and their connection to spin-currents","We calculate the frequency dependent spin susceptibilities for a
two-dimensional electron gas with both Rashba and Dresselhaus spin-orbit
interaction. The resonances of the susceptibilities depends on the relative
values of the Rashba and Dresselhaus spin-orbit constants, which could be
manipulated by gate voltages. We derive exact continuity equations, with source
terms, for the spin density and use those to connect the spin current to the
spin density. In the free electron model the susceptibilities play a central
role in the spin dynamics since both the spin density and the spin current are
proportional to them.",0406531v2
2005-01-06,Electron Spin Dynamics and Hyperfine Interactions in Fe/Al_0.1Ga_0.9As/GaAs Spin Injection Heterostructures,"We have studied hyperfine interactions between spin-polarized electrons and
lattice nuclei in Al_0.1Ga_0.9As/GaAs quantum well (QW) heterostructures. The
spin-polarized electrons are electrically injected into the semiconductor
heterostructure from a metallic ferromagnet across a Schottky tunnel barrier.
The spin-polarized electron current dynamically polarizes the nuclei in the QW,
and the polarized nuclei in turn alter the electron spin dynamics. The
steady-state electron spin is detected via the circular polarization of the
emitted electroluminescence. The nuclear polarization and electron spin
dynamics are accurately modeled using the formalism of optical orientation in
GaAs. The nuclear spin polarization in the QW is found to depend strongly on
the electron spin polarization in the QW, but only weakly on the electron
density in the QW. We are able to observe nuclear magnetic resonance (NMR) at
low applied magnetic fields on the order of a few hundred Oe by electrically
modulating the spin injected into the QW. The electrically driven NMR
demonstrates explicitly the existence of a Knight field felt by the nuclei due
to the electron spin.",0501096v1
2014-02-11,Dynamical decoupling design for identifying weakly coupled nuclear spins in a bath,"Identifying weakly coupled nuclear spins around single electron spins is a
key step of implementing quantum information processing using coupled
electron-nuclei spin systems or sensing like single spin nuclear magnetic
resonance detection using diamond defect spins. Dynamical decoupling control of
the center electron spin with periodic pulse sequences [e.g., the
Carre-Purcell-Meiboom-Gill (CPMG) sequence] has been successfully used to
identify single nuclear spins and to resolve structure of nuclear spin
clusters. Here, we design a new type of pulse sequences by replacing the
repetition unit (a single $\pi$-pulse) of the CPMG sequence with a group of
nonuniformly-spaced $\pi$-pulses. Using nitrogen-vacancy center system in
diamond, we show that the designed pulse sequence improves the resolution of
nuclear spin noise spectroscopy, and more information about the surrounding
nuclear spins is extracted. The principle of dynamical decoupling design
proposed in this paper is useful in many systems (e.g., defect spin qubit in
solids, trapped ion and superconducting qubit) for high-resolution noise
spectroscopy.",1402.2345v1
2014-11-11,Spin Relaxation Mechanism in a Highly Doped Organic Polymer Film,"We report the systematic studies of spin current transport and relaxation
mechanism in highly doped organic polymer film. In this study, we have
determined spin diffusion length (SDL), spin lifetime, and spin diffusion
constant by using different experimental techniques. The spin lifetime
estimated from the electron paramagnetic resonance experiment is much shorter
than the previous expectation beyond the experimental ambiguity. This suggests
that significantly large spin diffusion constant, which is reasonably explained
by the hopping transport mechanism in degenerate semiconductors, exists in
highly doped organic semiconductors. The calculated SDL using the spin lifetime
and spin diffusion constant estimated from our experiment is comparable to the
experimentally obtained SDL of the order of one hundred nanometers. Moreover,
the present study revealed that the spin angular momentum is almost preserved
in the hopping events. In other words, the spin relaxation mainly occurs due to
the spin-orbit coupling at the nanoscale crystalline grains.",1411.2740v1
2020-11-19,Determining complex spin mixing conductance and spin diffusion length from spin pumping experiments in magnetic insulator/heavy metal bilayers,"Magnetic insulators are promising materials for the development of
energy-efficient spintronics. Unlike metallic counterparts, the magnetic
insulators are characterized by imaginary part of the interfacial spin mixing
conductance as well in a bilayer with heavy metals and it is responsible for
the field-like toque in spin-orbit torque devices. Here, we study the
underlying theoretical constructs and develop a general strategy to determine
the complex spin mixing conductance from the experimental results of
ferromagnetic resonance and spin pumping. The results show that the imaginary
part of the spin mixing conductance can be one order more than the real part
and it matches the critical trend of spin mixing conductance with thickness of
the heavy metal. The interpretation of experimental results also indicates that
at small thicknesses the interface contribution becomes significant and bulk
diffusion model cannot explain the results. A thickness-dependent spin
diffusion length is necessary too that is tantamount to Elliott-Yafet spin
relaxation mechanism in the heavy metals. Also, we effectively explain the
experimental results while inserting a copper layer with varying thicknesses in
between the magnetic insulator and the heavy metal using spin-circuit
formalism.",2011.11055v1
2023-01-06,Interfacial magnetic anisotropy controlled spin pumping in Co60Fe20B20/Pt stack,"Controlled spin transport in magnetic stacks is required to realize pure spin
current-driven logic and memory devices. The control over the generation and
detection of the pure spin current is achieved by tuning the spin to charge
conversion efficiency of the heavy metal interfacing with ferromagnets. Here,
we demonstrate the direct tunability of spin angular momentum transfer and
thereby spin pumping, in CoFeB/Pt stack, with interfacial magnetic anisotropy.
The ultra-low thickness of CoFeB thin film tilts the magnetic easy axis from
in-plane to out-of-plane due to surface anisotropy. The Ferromagnetic resonance
measurements are performed to investigate the magnetic anisotropy and spin
pumping in CoFeB/Pt stacks. We clearly observe tunable spin pumping effect in
the CoFeB/Pt stacks with varying CoFeB thicknesses. The spin current density,
with varying ferromagnetic layer thickness, is found to increase from 0.11 to
0.24 MA/m2, with increasing in-plane anisotropy field. Such interfacial
anisotropy-controlled generation of pure spin current can potentially lead to
next-generation anisotropic spin current-controlled spintronic devices.",2301.02370v1
2023-07-22,Dense plasma irradiated platinum with improved spin Hall effect,"The impurity incorporation in host high-spin orbit coupling materials like
platinum has shown improved charge-to-spin conversion by modifying the up-spin
and down-spin electron trajectories by bending or skewing them in opposite
directions. This enables efficient generation, manipulation, and transport of
spin currents. In this study, we irradiate the platinum with non-focus dense
plasma to incorporate the oxygen ion species. We systematically analyze the
spin Hall angle of the oxygen plasma irradiated Pt films using spin torque
ferromagnetic resonance. Our results demonstrate a 2.4 times enhancement in the
spin Hall effect after plasma treatment of Pt as compared to pristine Pt. This
improvement is attributed to the introduction of disorder and defects in the Pt
lattice, which enhances the spin-orbit coupling and leads to more efficient
charge-to-spin conversion without breaking the spin-orbit torque symmetries.
Our findings offer a new method of dense plasma-based modification of material
for the development of advanced spintronic devices based on Pt and other heavy
metals.",2307.12139v1
2016-08-09,Polarons and Molecules in a Fermi Gas with Orbital Feshbach Resonance,"We study the impurity problem in a gas of $^{173}$Yb atoms near the recently
discovered orbital Feshbach resonance. In an orbital Feshbach resonance, atoms
in the electronic ground state $^1S_0$ interact with those in the long-lived
excited $^3P_0$ state with magnetically tunable interactions. We consider an
impurity atom with a given hyperfine spin in the $^3P_0$ state interacting with
a single-component Fermi sea of atoms in the ground $^1S_0$ manifold. Close to
the orbital Feshbach resonance, the impurity can induce collective
particle-hole excitations out of the Fermi sea, which can be regarded as the
polaron state. While as tuning toward the BEC regime of the resonance, a
molecular state becomes the ground state of the system. We show that a polaron
to molecule transition exists in $^{173}$Yb atoms close to the orbital Feshbach
resonance. Furthermore, due to the spin-exchange nature of the orbital Feshbach
resonance, the formation of both the polaron and the molecule involve
spin-flipping processes with interesting density distributions among the
relevant hyperfine spin states. We show that the polaron to molecule transition
can be detected using Raman spectroscopy.",1608.02744v2
2023-02-10,Booster Free From Spin Resonance For Future 100~km-scale Circular e$^{+}$e$^{-}$ Colliders,"Acceleration of polarized electron~(positron) beams in a booster synchrotron
may suffer from depolarization due to crossings of many spin depolarization
resonances, which could limit its applications. We have studied the spin
depolarization resonance structure of a 100~km scale booster lattice of the
Circular Electron Positron Collider~(CEPC). The lattice has 8 arc regions with
hundreds of FODO cells, interleaved with straight sections, which leads to a
high periodicity. Our analysis shows the contributions to the strength of
intrinsic and imperfection spin resonances add up coherently near the super
strong resonances beyond 120 GeV, but mostly cancel out and result in generally
weak resonance strengths at lower beam energies. Detailed simulations confirm
that beam polarization can be mostly maintained in the fast acceleration to
45.6 GeV and 80 GeV, but severe depolarization may occur at even higher
energies. This study suggests the possibility of acceleration of polarized
electron~(positron) beams to ultra-high beam energies without the help of
Siberian snakes, and supports injecting highly polarized beams into the
collider rings as an attractive solution for resonant depolarization
measurements and longitudinal polarized colliding beam experiments for future
100~km scale circular e$^{+}$e$^{-}$ colliders.",2302.05321v2
2013-05-13,New features of ion acoustic waves in inhomogeneous and permeating plasmas,"It is generally accepted that the ion acoustic (IA) wave in plasmas
containing ions and electrons with the same temperature is of minor importance
due to strong damping of the wave by hot resonant ions. In this work it will be
shown that the IA wave is susceptible to excitation even in plasmas with hot
ions when both an electromagnetic transverse wave and a background density
gradient are present in the plasma, and in addition the wave is in fact
unstable (i.e., growing) in the case of permeating homogeneous plasmas. The
multi-component fluid theory is used to describe the IA wave susceptibility for
excitation in inhomogeneous plasmas and its coupling with electromagnetic
waves. The growing IA wave in permeating homogeneous plasmas is described by
the kinetic theory. In plasmas with density and temperature gradients the IA
wave is effectively coupled with the electromagnetic waves. In comparison to
ordinary IA wave in homogeneous plasma, the Landau damping of the present wave
is much smaller, and to demonstrate this effect a simple but accurate fluid
model is presented for the Landau damping. In the case of permeating plasmas, a
kinetic mechanism for the current-less IA wave instability is presented, with a
very low threshold for excitation as compared with ordinary
electron-current-driven kinetic instability. Such growing IA waves can
effectively heat plasma in the upper solar atmosphere by a stochastic heating
mechanism presented in the work. The results of this work suggest that the IA
wave role in the heating of the solar atmosphere (chromosphere and corona)
should be reexamined.",1305.2739v1
2022-11-26,Triggered Ion-acoustic Waves,"The Parker Solar Probe is in a solar orbit with a perihelion for orbit 12 at
13.3 solar radii. The electric field experiment on this satellite observes what
we call triggered ion-acoustic waves as the most dominant wave mode above a few
Hz within the solar radial distance of 15-25 solar radii. In this mode, a few
Hz electrostatic wave is typically accompanied by bursts of a few hundred Hz
wave whose bursts are phase locked with each low frequency wave period. Plasma
density fluctuations with {\Delta}n/n~0.1 accompany these waves and they have
no magnetic field component. The wave durations can be hours and their field
and density fluctuations are nearly pure sine waves. They are identified as
ion-acoustic waves. The low and high frequency waves are measured to have the
same phase velocity within experimental uncertainties, which is a requirement
associated with their phase locked relationship. From the measured wavelength,
the potential associated with the low frequency wave is estimated to be ~10
Volts, which can result in electron heating via the Landau resonance that is in
agreement with observations of the core electron temperature increases at times
of such waves. Their phase locked relationship and pure frequency are
surprising features that characterize a new regime of instability and evolution
of ion-acoustic waves that may not have been reported previously. That these
waves are an instrumental effect unrelated to natural processes is considered.
While this is unlikely, the possibility that these waves are artificial cannot
be rule out",2211.14415v2
1999-11-29,Spin Waves in Canted Phases: An Application to Doped Manganites,"We present the effective lagrangian for low energy and momentum spin waves in
canted phases at next to leading order in the derivative expansion. The
symmetry breaking pattern SU(2) --> 1 of the internal spin group and that of
the crystallographic space group imply that there is one ferromagnetic and one
antiferromagnetic spin wave. The interaction of the spin waves with the charge
carriers is also discussed for canted, ferromagnetic and antiferromagnetic
phases. All this together allows us to write the doping dependence of the
dispersion relation parameters for doped manganites. We point out that the spin
waves posses distinctive characteristics which may allow us to experimentally
differentiate canted phases from phase separation regions in doped manganites.",9911471v2
2007-05-25,"Excitation of self-localized spin-wave ""bullets"" by spin-polarized current in in-plane magnetized magnetic nano-contacts: a micromagnetic study","It was shown by micromagnetic simulation that a current-driven in-plane
magnetized magnetic nano-contact, besides a quasi-linear propagating
(""Slonczewski"") spin wave mode, can also support a nonlinear self-localized
spin wave ""bullet"" mode that exists in a much wider range of bias currents. The
frequency of the ""bullet"" mode lies below the spectrum of linear propagating
spin waves, which makes this mode evanescent and determines its spatial
localization. The threshold current for the excitation of the self-localized
""bullet"" is substantially lower than for the linear propagating mode, but
finite-amplitude initial perturbations of magnetization are necessary to
generate a ""bullet"" in our numerical simulations, where thermal fluctuations
are neglected. Consequently, in these simulations the hysteretic switching
between the propagating and localized spin wave modes is found when the bias
current is varied.",0705.3750v1
2008-05-29,Wave packet dynamics in 2DEG with spin orbit coupling: splitting and zitterbewegung,"We study the effect of splitting and zitterbewegung of 1D and 2D electron
wave packets in the semiconductor quantum well under the influence of the
Rashba spin orbit coupling. Results of our investigations show that the spin
orbit interaction induces dramatic qualitative changes in the evolution of spin
polarized wave packet. The initial wave packet splits into two parts with
different spin polarization propagating with unequal group velocity. This
splitting appears due to the presence of two branches of electron spectrum
corresponding to the stationary states with different chirality. It is
demonstrated also that in the presence of external magnetic field B$
perpendicular to the electron gas plane the wave packet splits into two parts
which rotates with different cyclotron frequencies. It was shown that after
some periods the electron density distributes around cyclotron orbit and the
motion acquire an irregular character. Our calculations were made for both
cases of weak and strong spin orbit coupling.",0805.4489v2
2008-11-03,"Dispersion and spin wave ""tunneling"" in nano-structured magnetostatic spin waveguides","Magnetostatic spin wave dispersion and loss are measured in micron scale spin
wave-guides in ferromagnetic, metallic CoTaZr. Results are in good agreement
with model calculations of spin wave dispersion. The measured attenuation
lengths, of the order of 3um, are several of orders of magnitude shorter than
that predicted from eddy currents in these thin wires. Spin waves effectively
""tunnel"" through air gaps, produced by focused ion beam etching, as large as
1.5 um.",0811.0353v1
2009-07-13,A topological gauge field in nanomagnets: spin wave excitations over a slowly moving magnetization background,"We introduce a topological gauge vector potential which influences spin wave
excitations over arbitrary non-uniform, slowly moving magnetization
distribution. The time-component of the gauge potential plays a principal role
in magnetization dynamics, whereas its spatial components can be often
neglected for typical magnetic nanostructures. As an example, we consider spin
modes excited in the vortex state magnetic dots. It is shown that the vortex/
spin wave interaction can be described as a consequence of the gauge field
arising due to non uniform moving vortex magnetization distribution. The
coupled equations of motion of the vortex and spin waves are solved within
small excitation amplitude approximation. The model yields a giant frequency
splitting of the spin wave modes having non-zero overlapping with the vortex
mode as well as a finite vortex mass of dynamical origin.",0907.2226v1
2009-09-17,Experimental evidence of self-localized and propagating spin wave modes in obliquely magnetized current-driven nanocontacts,"Through detailed experimental studies of the angular dependence of spin wave
excitations in nanocontact-based spin-torque oscillators, we demonstrate that
two distinct spin wave modes can be excited, with different frequency,
threshold currents and frequency tuneability. Using analytical theory and
micromagnetic simulations we identify one mode as an exchange-dominated
propagating spin wave, and the other as a self-localized nonlinear spin wave
bullet. Wavelet-based analysis of the simulations indicates that the apparent
simultaneous excitation of both modes results from rapid mode hopping induced
by the Oersted field.",0909.3331v2
2010-07-06,"Spin waves in the (0,pi) and (0,pi,pi) ordered SDW states of the t-t' Hubbard model: Application to doped iron pnictides","Spin waves in (0,pi) and (0,pi,pi) ordered spin-density-wave (SDW) states of
the t-t' Hubbard model are investigated at finite doping. In the presence of
small t', these composite ferro-antiferromagnetic (F-AF) states are found to be
strongly stabilized at finite hole doping due to enhanced carrier-induced
ferromagnetic spin couplings as in metallic ferromagnets. Anisotropic spin-wave
velocities, spin-wave energy scale of around 200meV, reduced magnetic moment,
and rapid suppression of magnetic order with electron doping x (corresponding
to F substitution of O atoms in La O_{1-x} F_x Fe As or Ni substitution of Fe
atoms in Ba Fe_{2-x} Ni_x As_2) obtained in this model are in agreement with
observed magnetic properties of doped iron pnictides.",1007.0812v1
2011-04-27,Spin Density Waves and Domain Wall Interactions in Nanowires,"We investigated how the dynamics of a domain wall are affected by the
presence of spin density waves in a ferromagnetic wire. Domain walls and other
scattering centres can cause coherent spin density waves to propagate through a
wire when a current is applied. In some cases the spin torque due to these
scattered electrons can be enhanced such that it is on a par with the exchange
and anisotropy energies controlling the shape and dynamics of the domain wall.
In such a case we find that the spin density waves enhance the current induced
domain wall motion, allowing for domain wall motion with smaller current
pulses. Here we consider a system involving two domain walls and focus on how
the motion of the second domain wall is modified by the spin density waves
caused by the presence of the first domain wall.",1104.5175v1
2016-08-17,Current-induced instability of domain walls in cylindrical nanowires,"We study the current-driven domain wall (DW) motion in cylindrical nanowires
using micromagnetic simulations by implementing the Landau-Lifshitz-Gilbert
equation with nonlocal spin-transfer torque in a finite difference
micromagnetic package. We find that in the presence of DW Gaussian wave packets
(spin waves) will be generated when the charge current is applied to the system
suddenly. And this effect is excluded when using the local spin-transfer
torque. The existence of spin waves emission indicates that transverse domain
walls can not move arbitrarily fast in cylindrical nanowires although they are
free from the Walker limit. We establish an upper-velocity limit for the DW
motion by analyzing the stability of Gaussian wave packets using the local
spin-transfer torque. Micromagnetic simulations show that the stable region
obtained by using nonlocal spin-transfer torque is smaller than that by using
its local counterpart. This limitation is essential for multiple domain walls
since the instability of Gaussian wave packets will break the structure of
multiple domain walls.",1608.04876v2
2018-09-27,Spin wave radiation from vortices in $^3$He-B,"We consider a vortex line in the B phase of superfluid $^3$He under uniformly
precessing magnetization. The magnetization exerts torque on the vortex,
causing its order parameter to oscillate. These oscillations generate spin
waves, which is analogous to an oscillating charge generating electromagnetic
radiation. The spin waves carry energy, causing dissipation in the system.
Solving the equations of spin dynamics, we calculate the energy dissipation
caused by spin wave radiation for arbitrary tipping angles of the magnetization
and directions of the magnetic field, and for both vortex types of $^3$He-B.
For the double-core vortex we also consider the anisotropy of the radiation and
the dependence of the dissipation on twisting of the half cores. The radiated
energy is compared with experiments in the mid-temperature range $T \sim 0.5
T_c$. The dependence of the calculated dissipation on several parameters is in
good agreement with the experiments. Combined with numerically calculated
vortex structure, the radiation theory produces the order of magnitude of the
experimental dissipation. The agreement with the experiments indicates that
spin wave radiation is the dominant dissipation mechanism for vortices in
superfluid $^3$He-B in the mid-temperature range.",1809.10484v1
2018-07-03,Spin pinning and spin-wave dispersion in nanoscopic ferromagnetic waveguides,"Spin waves are investigated in Yttrium Iron Garnet (YIG) waveguides with a
thickness of 39 nm and widths ranging down to 50 nm, i.e., with aspect ratios
thickness over width approaching unity, using Brillouin Light Scattering
spectroscopy. The experimental results are verified by a semi-analytical theory
and micromagnetic simulations. A critical width is found, below which the
exchange interaction suppresses the dipolar pinning phenomenon. This changes
the quantization criterion for the spin-wave eigenmodes and results in a
pronounced modification of the spin-wave characteristics. The presented
semi-analytical theory allows for the calculation of spin-wave mode profiles
and dispersion relations in nano-structures.",1807.01358v3
2017-06-06,Temperature scaling of the Dzyaloshinsky-Moriya interaction in the spin wave spectrum,"The temperature scaling of the micromagnetic Dzyaloshinsky-Moriya exchange
interaction is calculated for the whole range of temperature. We use Green's
function theory to derive the finite-temperature spin wave spectrum of
ferromagnetic systems described by a classical atomistic spin model
Hamiltonian. Within this model, we find universal expressions for the
temperature scaling not only of the Dzyaloshinsky-Moriya interaction but also
of the Heisenberg exchange stiffness and the single-ion anisotropy. In the
spirit of multiscale models, we establish a clear connection between the
atomistic interactions and the temperature-dependent coefficients in the spin
wave spectrum and in the micromagnetic free energy functional. We demonstrate
that the corrections to mean-field theory or the random phase approximation for
the temperature scaling of Dzyaloshinsky-Moriya and Heisenberg exchange
interactions assume very similar forms. In the presence of thermal fluctuations
and Dzyaloshinsky-Moriya interaction an anisotropy-like term emerges in the
spin wave spectrum which, at low temperature, increases with temperature, in
contrast to the decreasing single-ion anisotropy. We evaluate the accuracy of
the theoretical method by comparing it to the spin wave spectrum calculated
from Monte Carlo simulations.",1706.01684v1
2021-11-29,Tailoring High-Frequency Magnonics in Monolayer Chromium Trihalides,"Monolayer chromium trihalides, the archetypal two dimensional (2D) magnetic
materials, are readily suggested as a promising platform for high frequency
magnonics. Here we detail the spin wave properties of monolayer CrBr$_3$ and
CrI$_3$, using spin dynamics simulations parametrized from the first
principles. We reveal that spin wave dispersion can be tuned in a broad range
of frequencies by strain, paving the way towards flexo magnonic applications.
We further show that ever present halide vacancies in these monolayers host
sufficiently strong Dzyaloshinskii Moriya interaction to scatter spin waves,
which promotes design of spin-wave guides by defect engineering. Finally we
discuss the spectra of spin-waves propagating across a moir\'e periodic
modulation of magnetic parameters in a van der Waals heterobilayer, and show
that the nanoscale moir\'e periodicities in such samples are ideal for
realization of a magnonic crystal in the terahertz frequency range. Recalling
the additional tunability of magnetic 2D materials by electronic gating, our
results situate these systems among the front-runners for prospective high
frequency magnonic applications.",2111.14305v1
2022-11-20,Long-distance propagation of high-velocity antiferromagnetic spin waves,"We report on coherent propagation of antiferromagnetic (AFM) spin waves over
a long distance ($\sim$10 $\mu$m) at room temperature in a canted AFM
$\alpha$-Fe$_2$O$_3$ with the Dzyaloshinskii-Moriya interaction (DMI).
Unprecedented high group velocities (up to 22.5 km/s) are characterized by
microwave transmission using all-electrical spin wave spectroscopy. We derive
analytically AFM spin-wave dispersion in the presence of the DMI which accounts
for our experimental results. The AFM spin waves excited by nanometric coplanar
waveguides with large wavevectors enter the exchange regime and follow a
quasi-linear dispersion relation. Fitting of experimental data with our
theoretical model yields an AFM exchange stiffness length of 1.7 angstrom. Our
results provide key insights on AFM spin dynamics and demonstrate high-speed
functionality for AFM magnonics.",2211.10989v1
2023-02-14,Spin wave Hamiltonian and anomalous scattering in NiPS$_3$,"We report a comprehensive spin wave analysis of the semiconducting honeycomb
van der Waal antiferromagnet NiPS$_3$. Using single crystal inelastic neutron
scattering, we map out the full Brillouin zone and fit the observed modes to a
spin wave model with rigorously defined uncertainty. We find that the third
neighbor exchange $J_3$ dominates the Hamiltonian, a feature which we fully
account for by ab-initio density functional theory calculations. We also
quantify the degree to which the three-fold rotation symmetry is broken and
account for the $Q=0$ excitations observed in other measurements, yielding a
spin exchange model which is consistent across multiple experimental probes. We
also identify a strongly reduced static ordered moment and reduced low-energy
intensity relative to the linear spin wave calculations, signaling unexplained
features in the magnetism which requires going beyond the linear spin wave
approximation.",2302.07242v2
2023-04-03,Spin waves in layered antiferromagnets with honeycomb structure,"We develop a description of spin waves in a $3D$ quantum $XY$ antiferromagnet
(AFM) in terms of macroscopic variables, magnetization and N\'eel vector
densities. We consider a layered AFM with spins located on the honeycomb
lattice. In the discussed system, the spectrum of spin waves consists of four
modes, all well captured by our macroscopic description. The gapless mode of
the spin waves, i.e., magnons, is described by a system of equations, which has
a structure general for the Goldstone mode in AFMs. We demonstrate that the
parameters in the spin Hamiltonian can be evaluated by fitting the experimental
data with the results obtained for the four modes using the macroscopic
variable approach. The description of AFM in terms of macroscopic variables can
be easily extended to the case when the lattice of the magnetic substance is
deformed by an external strain or acoustic wave.",2304.00700v1
2018-08-15,Mode-conversion of the extraordinary wave at the upper hybrid resonance in the presence of small-amplitude density fluctuations,"In spherical tokamaks, the electron plasma frequency is greater than the
electron cyclotron frequency. Electromagnetic waves in the electron cyclotron
range of frequencies are unsuitable for directly heating such plasmas due to
their reduced accessibility. However, mode-conversion of the extraordinary wave
to the electron Bernstein wave (X-B mode-conversion) at the upper hybrid
resonance makes it possible to efficiently couple externally-launched
electromagnetic wave energy into an overdense plasma core. Traditional
mode-conversion models describe an X-mode wave propagating in a potential
containing two cutoffs that bracket a single wave resonance. Often, however,
the mode-conversion region is in the edge, where turbulent fluctuations and
blobs can generate abrupt cutoffs and scattering of the incident X-mode wave.
We present a new framework for studying the X-B mode-conversion which makes the
inclusion of these fluctuations analytically tractable. In the new approach,
the high-field cutoff is modelled as an infinite barrier, which manifests as a
boundary condition applied to a wave equation involving only one cutoff
adjacent to the resonance on the low-field side. The new model reproduces the
main features of the previous approach, yet is more suitable for analyzing
experimental observations and extrapolating to higher dimensions. We then
develop an analytical estimate for the effect of small-amplitude,
quasi-monochromatic density fluctuations on the X-B mode-conversion efficiency
using perturbation theory. We find that Bragg backscattering of the launched
X-mode wave reduces the mode-conversion efficiency significantly when the
fluctuation wavenumber is resonant with the wavenumber of the incident X-mode
wave. These analytical results are corroborated by numerically integrating the
mode-conversion equations.",1808.05282v2
2019-11-18,Optical control of an individual Cr spin in a semiconductor quantum dot,"We demonstrate that the spin of a Cr atom in a quantum dot (QD) can be
controlled optically and we discuss the main properties of this single spin
system. The photoluminescence of individual Cr-doped QDs and their evolution in
magnetic field reveal a large magnetic anisotropy of the Cr spin induced by
local strain. This results in a splitting of the Cr spin states and in a
thermalization on the lower energy states states S$_z$=0 and S$_z$=$\pm$1. The
magneto-optical properties of Cr-doped QDs can be modelled by an effective spin
Hamiltonian including the spin to strain coupling and the influence of the QD
symmetry. We also show that a single Cr spin can be prepared by resonant
optical pumping. Monitoring the intensity of the resonant fluorescence of the
QD during this process permits to probe the dynamics of the optical
initialization of the spin. Hole-Cr flip-flops induced by an interplay of the
hole-Cr exchange interaction and the coupling with acoustic phonons are the
main source of relaxation that explains the efficient resonant optical pumping.
The Cr spin relaxation time is measured in the $\mu s$ range. We evidence that
a Cr spin couples to non-equilibrium acoustic phonons generated during the
optical excitation inside or near the QD). Finally we show that the energy of
any spin state of an individual Cr atom can be independently tuned by a
resonant single mode laser through the optical Stark effect. All these
properties make Cr-doped QDs very promising for the development of hybrid
spin-mechanical systems where a coherent mechanical driving of an individual
spin in an oscillator is required.",1911.08572v1
2020-06-17,Recent Progress on Electrical Excitation and Manipulation of Spin-Waves in Spin Hall Nano-Oscillators,"Spin waves (SWs), the collective precessional motion of spins in a magnetic
system, have been proposed as a promising alternative system with low-power
consumption for encoding information. Spin Hall nano-oscillator (SHNO), a
new-type spintronic nano-device, can electrically excite and control spin waves
in both nanoscale magnetic metals and insulators with low damping by the spin
current due to spin Hall effect. Here, we will review recent progress about
spin-wave excitation and experimental parameters dependent spectrum in SHNOs.
The nanogap SHNOs based on in-plane magnetization Py/Pt exhibits a nonlinear
self-localized bullet soliton localized at the center of the gap between the
electrodes and a secondary high-frequency mode which coexists with the primary
bullet mode at higher currents. While in the nanogap SHNOs with strong
perpendicular magnetic anisotropy (PMA), besides both nonlinear bullet soliton
and propagating spin-wave mode are achieved and controlled by varying the
external magnetic field and current, the magnetic bubble skyrmion mode also can
be excited at a low in-plane magnetic field. These SW modes show
thermal-induced mode hopping behavior at high temperature due to the coupling
between modes mediated by thermal-magnon-mediated scattering. Moreover, thanks
to PMA-induced effective field, a single coherent mode also can be achieved
without applying an external magnetic field. The strong nonlinear effect of
spin-waves makes SHNOs easy to achieve synchronization with external microwave
signals or mutual synchronization between multiple oscillators with improving
the coherence and power of oscillation modes significantly. Spin-waves in SHNOs
with an external free magnetic layer have a wide range of applications from as
a nanoscale signal source of low-power consumption magnonic devices to
spin-based neuromorphic computing systems in the field of artificial
intelligence.",2006.09737v2
2018-10-25,Light-Quark Resonances at COMPASS,"The main goal of the spectroscopy program at COMPASS is to explore the
light-meson spectrum in the mass range below about $2\,\text{GeV}/c^2$ using
diffractive dissociation reactions. Our flagship channel is the production of
three charged pions in the reaction: $\pi^- + p \to \pi^-\pi^-\pi^+ +
p_\text{recoil}$, for which COMPASS has acquired the so far world's largest
dataset of roughly $50\,\text{M}$ exclusive events using an $190\,\text{GeV}/c$
$\pi^-$ beam.
  In order to extract the parameters of the $\pi_J$ and $a_J$ resonances that
appear in the $\pi^-\pi^-\pi^+$ system, we performed the so far most
comprehensive resonance-model fit, using Breit-Wigner parametrizations. This
method in combination with the high statistical precision of our data allows us
to study ground and excited states. We study the $a_4(2040)$ resonance in the
$\rho(770)\pi G$ and $f_2(1270)\pi F$ decays. In addition to the ground state
resonance $a_1(1260)$, we have found evidence for the $a_1(1640)$. We also
study the spectrum of $\pi_2$ states by simultaneously describing four
$J^{PC}=2^{-+}$ waves using three $\pi_2$ resonances, the $\pi_2(1670)$, the
$\pi_2(1880)$, and the $\pi_2(2005)$.
  Using a novel analysis approach, where the resonance-model fit is performed
simultaneously in narrow bins of the squared four-momentum transfer $t'$
between the beam pion and the target proton, allows us to study the $t'$
dependence of resonant and non-resonant components included in our model. We
observe that for most of the partial waves, the non-resonant components show a
steeper $t'$ spectrum compared to the resonances and that the $t'$ spectrum of
most of the resonances becomes shallower with increasing resonance mass. We
also study the $t'$ dependence of the relative phases between resonance
components. The pattern we observe is consistent with a common production
mechanism of these states.",1810.10805v1
2005-04-13,NMR relaxation rate in non-centrosymmetric superconductors,"The spin-lattice relaxation rate of nuclear magnetic resonance in a clean
superconductor without inversion center is calculated for arbitrary pairing
symmetry and band structure, in the presence of strong spin-orbit coupling.",0504342v1
2020-10-03,Modulated longitudinal gates on encoded spin-qubits via curvature couplings to a superconducting cavity,"We propose entangling operations based on the energy curvature couplings of
encoded spin qubits to a superconducting cavity, exploring the non-linear qubit
response to a gate voltage variation. For a two-qubit ($n$-qubit) entangling
gate we explore acquired geometric phases via a time-modulated longitudinal
$\sigma_z$-coupling, offering gate times of 10s of ns even when the qubits and
the cavity are far detuned. No dipole moment is necessary: the qubit transverse
$\sigma_x$-coupling to the resonator is zero at the full sweet spot of the
encoded spin qubit of interest (a triple quantum dot three-electron
exchange-only qubit or a double quantum dot singlet-triplet qubit). This
approach allows always-on, exchange-only qubits, for example, to stay on their
""sweet spots"" during gate operations, minimizing the charge noise and
eliminating an always-on static longitudinal qubit-qubit coupling. We calculate
the main gate errors due to the (1) diffusion (Johnson) noise and (2) damping
of the resonator, the (3) $1/f$-charge noise qubit gate dephasing and
$1/f$-noise on the longitudinal coupling, (4) qubit dephasing and ac-Stark
frequency shifts via photon fluctuations in the resonator, and (5)
spin-dependent resonator frequency shifts (via a ""dispersive-like"" static
curvature coupling), most of them associated with the non-zero qubit energy
curvature (quantum capacitance). Using spin-echo-like error suppression at
optimal regimes, gate infidelities of $10^{-2}-10^{-3}$ can be achieved with
experimentally existing parameters. The proposed schemes seem suitable for
remote spin-to-spin entanglement of two spin-qubits or a cluster of
spin-qubits: an important resource of quantum computing.",2010.01233v1
2022-03-15,Spin-optical dynamics and quantum efficiency of single V1 center in silicon carbide,"Color centers in silicon carbide are emerging candidates for distributed
spin-based quantum applications due to the scalability of host materials and
the demonstration of integration into nanophotonic resonators. Recently,
silicon vacancy centers in silicon carbide have been identified as a promising
system with excellent spin and optical properties. Here, we in-depth study the
spin-optical dynamics of single silicon vacancy center at hexagonal lattice
sites, namely V1, in 4H-polytype silicon carbide. By utilizing resonant and
above-resonant sub-lifetime pulsed excitation, we determine spin-dependent
excited-state lifetimes and intersystem-crossing rates. Our approach to
inferring the intersystem-crossing rates is based on all-optical pulsed
initialization and readout scheme, and is applicable to spin-active color
centers with similar dynamics models. In addition, the optical transition
dipole strength and the quantum efficiency of V1 defect are evaluated based on
coherent optical Rabi measurement and local-field calibration employing
electric-field simulation. The measured rates well explain the results of
spin-state polarization dynamics, and we further discuss the altered
photoemission dynamics in resonant enhancement structures such as radiative
lifetime shortening and Purcell enhancement. By providing a thorough
description of V1 center's spin-optical dynamics, our work provides deep
understanding of the system which guides implementations of scalable quantum
applications based on silicon vacancy centers in silicon carbide.",2203.08177v2
2001-12-19,Spin-phonon interaction in doped high-T$_C$ superconductors from density functional calculations,"Effects of coupling between phonon distortions and stripe-like spin waves in
the CuO plane of HgBa$_2$CuO$_4$ are studied by band calculations. Local
exchange enhancements depend sensitively on the local structure around Cu
sites. Interactions where spin waves have twice as long wave length as phonon
waves can lead to a 'dip' in the density of states (DOS) below the Fermi
energy, $E_F$. This type of interaction is compatible with several seemingly
contradictory observations among high-$T_C$ cuprates, like the isotope effect,
anti-ferromagnetic fluctuations, stripes and pseudogaps. It can also account
for a large $T_C$.",0112357v1
1997-01-27,Massless fields in plane wave geometry,"Conformal isometry algebras of plane wave geometry are studied. Then, based
on the requirement of conformal invariance, a definition of masslessness is
introduced and gauge invariant equations of motion, subsidiary conditions, and
corresponding gauge transformations for all plane wave geometry massless spin
fields are constructed. Light cone representation for elements of conformal
algebra acting as differential operators on wavefunctions of massless higher
spin fields is also evaluated. Interrelation of plane wave geometry massless
higher spin fields with ladder representation of $u(2,2)$ algebra is
investigated.",9701141v1
2009-01-15,Spin-Wave Instabilities and Non-Collinear Magnetic Phases of a Geometrically-Frustrated Triangular-Lattice Antiferromagnet,"This paper examines the relation between the spin-wave instabilities of
collinear magnetic phases and the resulting non-collinear phases for a
geometrically-frustrated triangular-lattice antiferromagnet in the high spin
limit. Using a combination of phenomenological and Monte-Carlo techniques, we
demonstrate that the instability wave-vector with the strongest intensity in
the collinear phase determines the wave-vector of a cycloid or the dominant
elastic peak of a more complex non-collinear phase. Our results are related to
the observed multi-ferroic phase of Al-doped CuFeO$_2$.",0901.2336v1
2012-05-08,Quantum phases of Bose-Bose mixtures on a triangular lattice,"We investigate the zero temperature quantum phases of a Bose-Bose mixture on
a triangular lattice using Bosonic Dynamical Mean Field Theory (BDMFT). We
consider the case of total filling one where geometric frustration arises for
asymmetric hopping. We map out a rich ground state phase diagram including
xy-ferromagnetic, spin-density wave, superfluid, and supersolid phases. In
particular, we identify a stripe spin-density wave phase for highly asymmetric
hopping. On top of the spin-density wave, we find that the system generically
shows weak charge (particle) density wave order.",1205.1806v2
2021-07-04,Spin optics for gravitational waves,"We present the geometric optics expansion for circularly polarized
gravitational waves on a curved spacetime background, to subleading order. We
call spin optics to the subleading order geometric optics expansion, which
involves modifying the standard eikonal function by including a specially
chosen helicity-dependent correction. We show that the techniques developed for
the propagation of electromagnetic waves can also be applied to gravitational
waves in the limit of spin optics. However, one needs to account for the
difference in the photon and graviton helicity, which we do here.",2107.02761v3
2023-03-09,Full-waveform tomography reveals iron spin crossover in Earth lower mantle,"Joint interpretation of bulk and shear wave speeds constrains the chemistry
of the deep mantle. At all depths, the diversity of wave speeds cannot be
explained by an isochemical mantle. Between 1000 and 2500 km depth,
hypothetical mantle models containing an electronic spin crossover in (Mg,Fe)O
provide a significantly better fit to the wave-speed distributions, as well as
more realistic temperatures and silica contents, than models without a spin
crossover. Below 2500 km, wave speed distributions are explained by enrichment
in silica towards the core-mantle-boundary. This silica enrichment may
represent the fractionated remains of an ancient basal magma ocean.",2303.05476v1
2016-01-08,Kinetic Simulation of Slow Magnetosonic Waves and Quasi-periodic Upflows in the Solar Corona,"Quasi-periodic disturbances of emission-line parameters are frequently
observed in the corona. These disturbances propagate upward along the magnetic
field with speeds $\sim100~\rm{km~s}^{-1}$. This phenomenon has been
interpreted as evidence of the propagation of slow magnetosonic waves or argued
to be signature of the intermittent outflows superposed on the background
plasmas. Here we aim to present a new ""wave + flow"" model to interpret these
observations. In our scenario, the oscillatory motion is a slow mode wave, and
the flow is associated with a beam created by the wave-particle interaction
owing to Landau resonance. With the help of a Vlasov model, we simulate the
propagation of the slow mode wave and the generation of the beam flow. We find
that weak periodic beam flows can be generated owing to Landau resonance in the
solar corona, and the phase with strongest blueward asymmetry is ahead of that
with strongest blueshift by about 1/4 period. We also find that the slow wave
damps to the level of 1/e after the transit time of two wave periods, owing to
Landau damping and Coulomb collisions in our simulation. This damping time
scale is similar to that resulting from thermal-conduction in the
magnetohydrodynamics regime. The beam flow is weakened/attenuated with
increasing wave period and decreasing wave amplitude since Coulomb collision
becomes more and more dominant over the wave action. We suggest that this ""wave
+ flow"" kinetic model provides an alternative explanation for the observed
quasi-periodic propagating perturbations in various parameters in the solar
corona.",1601.01823v1
2017-11-08,Modulation instability of lower hybrid waves leading to cusp solitons in electron-positron-ion Thomas Fermi plasma,"Following the idea of three wave resonant interactions of lower hybrid waves
it is shown that quantum -modified lower hybrid (QLH) wave in electron positron
ion plasma with spatial dispersion can decay into another QLH wave ( where
electron and positrons are activated whereas ions remain in the background) and
another ultra low frequency QULH (where ions are mobile). Quantum effects like
Bohm potential, exchange correlation and Fermi pressure on the lower hybrid
wave significantly reshaped the dispersion properties of lower hybrid waves.
Later a set of nonlinear Zakharov equations have been derived to consider the
formation of QLH wave solitons with the nonlinear contribution coming from the
QLH waves. Further, modulational instability of the lower hybrid wave solitons
is investigated and consequently it's growth rates are examined for different
limiting cases. Since the growth rate associated with the three-wave resonant
interaction are generally smaller than the growth associated with the
modulational instability, therefore only latter have been investigated. Soliton
solutions from the set of coupled Zakharov and NLS equations in the
quasi-stationary regime have been studied. Ordinary solitons are attribute of
nonlinearity whereas a cusp soliton solution featured by nonlocal nonlinearity
have also studied. Such an approach to lower hybrid waves and cusp solitons
study in Fermi gas comprising electron positron and ions is new and important.
The general results obtained in this quantum plasma theory will have widespread
applicability, particularly for processes in high energy plasma-laser
interactions set for laboratory astrophysics and solid state plasmas.",1711.03186v1
2023-11-27,Control water waves by metagratings,"Metasurfaces and metagratings offers new platforms for electromagnetic wave
control with significant responses. However, metasurfaces based on abrupt phase
change and resonant structures suffer from the drawback of high loss and face
challenges when applied in water waves. Therefore, the application of
metasurfaces in water wave control is not ideal due to the limitations
associated with high loss and other challenges. We have discovered that
non-resonant metagratings exhibit promising effects in water wave control.
Leveraging the similarity between bridges and metagratings, we have
successfully developed a water wave metagrating model inspired by the Luoyang
Bridge in ancient China. We conducted theoretical calculations and simulations
on the metagrating and derived the equivalent anisotropic model of the
metagrating. This model provides evidence that the metagrating has the
capability to control water waves and achieve unidirectional surface water
wave. The accuracy of our theory is strongly supported by the clear observation
of the unidirectional propagation phenomenon during simulation and experiments
conducted using a reduced version of the metagrating. It is the first time that
the unidirectional propagation of water waves has been seen in water wave
metagrating experiment. Above all, we realize the water wave metagrating
experiment for the first time. By combining complex gratings with real bridges,
we explore the physics embedded in the ancient building-Luoyang Bridge, which
are of great significance for the water wave metagrating design, as well as the
development and preservation of ancient bridges.",2311.15795v1
2013-02-26,Resonant state selection in synthetic ferrimagnets,"Resonant activation of a synthetic antiferromagnet (SAF) is known to result
in a dynamic running state, where the SAF's symmetric spin-flop pair
continuously rotates between the two antiparallel ground states of the system,
with the two magnetic moments in-phase in the so-called acoustical
spin-resonance mode. The symmetry of an ideal SAF does not allow, however, to
deterministically select a particular ground state using a resonant excitation.
In this work, we study asymmetric SAF's, or synthetic ferrimagnets (SFi), in
which the two magnetic particles are different in thickness or are biased
asymmetrically with an external field. We show how the magnetic phase space of
the system can be reversibly tuned, post-fabrication, between the antiferro-
and ferri-magnetic behavior by exploiting these two asymmetry parameters and
applying a uniform external field. We observe a splitting of the optical
spin-resonance for the two ground states of the SFi system, with a frequency
spacing that can be controlled by a quasistatic uniform external field. We
demonstrate how the tunable magnetic asymmetry in SFi allows to
deterministically select a particular ground state using the splitting of the
optical spin-resonance. These results offer a new way of controlling the
magnetic state of a spin-flop bilayer, currently used in such large scale
applications as magnetic memory.",1302.6483v2
2015-04-23,Subharmonic transitions and Bloch-Siegert shift in electrically driven spin resonance,"We theoretically study coherent subharmonic (multi-photon) transitions of a
harmonically driven spin. We consider two cases: magnetic resonance (MR) with a
misaligned, i.e., non-transversal driving field, and electrically driven spin
resonance (EDSR) of an electron confined in a one-dimensional, parabolic
quantum dot, subject to Rashba spin-orbit interaction. In the EDSR case, we
focus on the limit where the orbital level spacing of the quantum dot is the
greatest energy scale. Then, we apply time-dependent Schrieffer-Wolff
erturbation theory to derive a time-dependent effective two-level Hamiltonian,
allowing to describe both MR and EDSR using the Floquet theory of periodically
driven two-level systems. In particular, we characterise the fundamental
(single-photon) and the half-harmonic (two-photon) spin transitions. We
demonstrate the appearance of two-photon Rabi oscillations, and analytically
calculate the fundamental and half-harmonic resonance frequencies and the
corresponding Rabi frequencies. For EDSR, we find that both the fundamental and
the half-harmonic resonance frequency changes upon increasing the strength of
the driving electric field, which is an effect analogous to the Bloch-Siegert
shift known from MR. Remarkably, the drive-strength dependent correction to the
fundamental EDSR resonance frequency has an anomalous, negative sign, in
contrast to the corresponding Bloch-Siegert shift in MR which is always
positive. Our analytical results are supported by numerical simulations, as
well as by qualitative interpretations for simple limiting cases.",1504.06081v2
2017-12-18,Search for heavy $ZZ$ resonances in the $\ell^+\ell^-\ell^+\ell^-$ and $\ell^+\ell^-ν\barν$ final states using proton proton collisions at $\sqrt{s}= 13$ TeV with the ATLAS detector,"A search for heavy resonances decaying into a pair of $Z$ bosons leading to
$\ell^+\ell^-\ell^+\ell^-$ and $\ell^+\ell^-\nu\bar\nu$ final states, where
$\ell$ stands for either an electron or a muon, is presented. The search uses
proton proton collision data at a centre-of-mass energy of 13 TeV corresponding
to an integrated luminosity of 36.1 fb$^{-1}$ collected with the ATLAS detector
during 2015 and 2016 at the Large Hadron Collider. Different mass ranges for
the hypothetical resonances are considered, depending on the final state and
model. The different ranges span between 200 GeV and 2000 GeV. The results are
interpreted as upper limits on the production cross section of a spin 0 or spin
2 resonance. The upper limits for the spin 0 resonance are translated to
exclusion contours in the context of Type I and Type II two-Higgs-doublet
models, while those for the spin 2 resonance are used to constrain the Randall
Sundrum model with an extra dimension giving rise to spin 2 graviton
excitations.",1712.06386v2
2017-04-11,Synergetic effect of spin-orbit coupling and Zeeman splitting on the optical conductivity in the one-dimensional Hubbard model,"We study how the synergetic effect of spin-orbit coupling (SOC) and Zeeman
splitting (ZS) affects the optical conductivity in the one-dimensional Hubbard
model using the Kubo formula. We focus on two phenomena: (1) the electric
dipole spin resonance (EDSR) in the metallic regime and (2) the optical
conductivity in the Mott-insulating phase above the optical gap. In both cases,
we calculate qualitatively the effects of SOC and ZS and how they depend on the
relative angle between the SOC vector and the magnetic field direction. First,
we investigate the spin resonance without electron correlation (the Hubbard
parameter $U=0$). Although, neither SOC nor ZS causes any resonance by itself
in the optical conductivity, the EDSR becomes possible when both of them exist.
The resulting contribution to the optical conductivity is analyzed
analytically. The effect of $U$ on the spin resonance is also studied with a
numerical method. It is found that at half-filling, the resonance is first
enhanced for small $U$ and then suppressed when the optical gap is large
enough. In the strong coupling limit $U \rightarrow \infty$ at half-filling, we
also refer to the resonance between the lower and upper Hubbard bands appearing
at $\omega \sim U$, above the optical gap. A large magnetic field tends to
suppress the signal while it is recovered thanks to SOC depending on the
relative angle of the magnetic field.",1704.03153v2
2020-05-13,Neutron spin resonance in a quasi-two-dimensional iron-based superconductor,"Magnetically mediated Cooper pairing is generally regarded as a key to
establish the unified mechanism of unconventional superconductivity. One
crucial evidence is the neutron spin resonance arising in the superconducting
state, which is commonly interpreted as a spin-exciton from collective
particle-hole excitations confined below the superconducting pair-breaking gap
($2\Delta$). Here, on the basis of inelastic neutron scattering measurements on
a quasi-two-dimensional iron-based superconductor KCa$_2$Fe$_4$As$_4$F$_2$, we
have discovered a two-dimensional spin resonant mode with downward dispersions,
a behavior closely resembling the low branch of the hour-glass-type spin
resonance in cuprates. The resonant intensity is predominant by two broad
incommensurate peaks near $Q=$(0.5, 0.5) with a sharp energy peak at $E_R=16$
meV. The overall energy dispersion of the mode exceeds the measured maximum
total gap $\Delta_{\rm tot}=|\Delta_k|+|\Delta_{k+Q}|$. These experimental
results deeply challenge the conventional understanding of the resonance modes
as magnetic excitons regardless of underlining pairing symmetry schemes, and it
also points out that when the iron-based superconductivity becomes very
quasi-two-dimensional, the electronic behaviors are similar to those in
cuprates.",2005.06146v1
2013-02-19,Readout and control of a single nuclear spin with a meta-stable electron spin ancilla,"Electron and nuclear spins associated with point defects in insulators are
promising systems for solid state quantum technology. While the electron spin
usually is used for readout and addressing, nuclear spins are exquisite quantum
bits and memory systems. With these systems single-shot readout of nearby
nuclear spins as well as entanglement aided by the electron spin has been
shown. While the electron spin in this example is essential for readout it
usually limits nuclear spin coherence. This has set of the quest for defects
with spin-free ground states. Here, we isolate a hitherto unidentified defect
in diamond and use it at room temperature to demonstrate optical spin
polarization and readout with exceptionally high contrast (up to 45%), coherent
manipulation of an individual excited triplet state spin, and coherent nuclear
spin manipulation using the triplet electron spin as a meta-stable ancilla. By
this we demonstrate nuclear magnetic resonance and Rabi oscillations of the
uncoupled nuclear spin in the spin-free electronic ground state. Our study
demonstrates that nuclei coupled to single metastable electron spins are useful
quantum systems with long memory times despite electronic relaxation processes.",1302.4608v1
2019-04-26,Measurement of the Spin Tune Using the Coherent Spin Motion of Polarized Proton in a Storage Ring,"This paper reports the first spin tune measurement at high energies (24 GeV
and 255 GeV) with a driven coherent spin motion. To maintain polarization in a
polarized proton collider, it is important to know the spin tune of the
polarized proton beam, which is defined as the number of full spin precessions
per revolution. A nine-magnet spin flipper has demonstrated high spin-flip
efficiency in the presence of two Siberian snakes [1]. The spin flipper drives
a spin resonance with a given frequency (or tune) and strength. When the drive
tune is close to the spin tune, the proton spin direction is not vertical
anymore, but precesses around the vertical direction. By measuring the
precession frequency of the horizontal component the spin tune can be precisely
measured. A driven coherent spin motion and fast turn-by-turn polarization
measurement are keys to the measurement. The vertical spin direction is
restored after turning the spin flipper off and the polarization value is not
affected by the measurement. The fact that this manipulation preserves the
polarization makes it possible to measure the spin tune during operation of a
high energy accelerator.",1904.12049v1
1998-06-25,Quantum Hall effect anomaly and collective modes in the magnetic-field-induced spin-density-wave phases of quasi-one-dimensional conductors,"We study the collective modes in the magnetic-field-induced spin-density-wave
(FISDW) phases experimentally observed in organic conductors of the Bechgaard
salts family. In phases that exhibit a sign reversal of the quantum Hall effect
(Ribault anomaly), the coexistence of two spin-density waves gives rise to
additional collective modes besides the Goldstone modes due to spontaneous
translation and rotation symmetry breaking. These modes strongly affect the
charge and spin response functions. We discuss some experimental consequences
for the Bechgaard salts.",9806311v2
1999-09-10,Time Evolution of Spin Waves,"A rigorous derivation of macroscopic spin-wave equations is demonstrated. We
introduce a macroscopic mean-field limit and derive the so-called
Landau-Lifshitz equations for spin waves. We first discuss the ferromagnetic
Heisenberg model at T=0 and finally extend our analysis to general spin
hamiltonians for the same class of ferromagnetic ground states.",9909146v1
2000-05-26,Spin and charge excitations in incommensurate spin density waves,"Collective excitations both for spin- and charge-channels are investigated in
incommensurate spin density wave (or stripe) states on two-dimensional Hubbard
model. By random phase approximation, the dynamical susceptibility
\chi(q,\omega) is calculated for full range of (q,\omega) with including all
higher harmonics components. An intricate landscape of the spectra in
\chi(q,\omega) is obtained. We discuss the anisotropy of the dispersion cones
for spin wave excitations, and for the phason excitation related to the motion
of the stripe line. Inelastic neutron experiments on Cr and its alloys and
stripe states of underdoped cuprates are proposed.",0005466v1
2002-10-04,Current-induced spin-wave excitations in a single ferromagnetic layer,"A new current induced spin-torque transfer effect has been observed in a
single ferromagnetic layer without resorting to multilayers. At a specific
current density of one polarity injected from a point contact, abrupt
resistance changes due to current-induced spin wave excitations have been
observed. The critical current at the onset of spin-wave excitations depends
linearly on the external field applied perpendicular to the layer. The observed
effect is due to current-driven heterogeneity in an otherwise uniform
ferromagnetic layer.",0210116v1
2004-11-13,Existence of the Spin-Wave Gap in a Deformed Flat-Band Hubbard Model,"We consider a deformed flat-band Hubbard model under a periodic boundary
condition in arbitrary dimensions. We show that the ground state is only
all-spin-up or -down state. We obtain upper and lower bounds of the one-magnon
spin-wave energy with an arbitrary momentum. This dispersion relation is the
same as that in the XXZ model in the certain parameter region. Therefore the
spin wave has a finite energy gap. These results suggests the our model and the
XXZ model.",0411362v1
2004-05-11,Spin structure of spin-1/2 baryon and spinless meson production amplitudes in photo and hadronic reactions,"The most general spin structures of the spin-1/2 baryon and spinless meson
production operator for both photon and nucleon induced reactions are derived
from the partial-wave expansions of these reaction amplitudes. The present
method provides the coefficients multiplying each spin operator in terms of the
partial-wave matrix elements. The result should be useful in studies of these
reactions based on partial-wave analyses, especially, when spin observables are
considered.",0405030v4
2007-01-10,Experimental demonstration of stimulated polarization wave in a chain of nuclear spins,"A stimulated wave of polarization, which implements a simple mechanism of
quantum amplification, is experimentally demonstrated in a chain of four
J-coupled nuclear spins, irradiated by a weak radio-frequency transverse field.
The ""quantum domino"" dynamics, a wave of flipped spins triggered by a flip of
the first spin, has been observed in fully $^{13}$C-labeled sodium butyrate.",0701056v1
2007-08-09,Spin-wave spectra of a kagome stripe,"We study ground state degeneracy and spin-wave excitations in a 1D version of
a Kagome antiferromagnet -- a Heisenberg antiferromagnet on a Kagome stripe. We
show that for nearest-neighbor interaction, the classical ground state is
infinitely degenerate. For any spin configuration from the degenerate set, the
classical spin-wave spectrum contains, in addition to Goldstone modes, a branch
of zero energy excitations, and a zero mode in another branch. We demonstrate
that the interactions beyond nearest neighbors lift the degeneracy, eliminate a
zero mode, and give a finite dispersion to formerly zero-energy branch, leaving
only Goldstone modes as zero-energy excitations.",0708.1272v1
2009-06-09,Spin-wave theory for dimerized ferromagnetic chains,"We describe a Peierls dimerization which occurs in ferromagnetic spin chains
at finite temperature, within the modified spin-wave theory. Usual spin-wave
theory is modified by introducing a Lagrange multiplier which enforces a
nonmagnetic state at finite temperature. It is shown that this method gives
results in excellent agreement with the density--matrix renormalization group
applied to transfer matrices for dimerized ferromagnetic chains. We study bond
correlation functions and explore the characteristic features of dimerization
in the specific heat.",0906.1758v1
2009-12-25,Near-Boundary and Bulk Regions of a Semi-Infinite Two-Dimensional Heisenberg Antiferromagnet,"Using the spin-wave approximation elementary excitations of a semi-infinite
two-dimensional $S=\frac12$ Heisenberg antiferromagnet are considered. The
spectrum consists of bulk modes -- standing spin waves and a
quasi-one-dimensional mode of boundary spin waves. These latter excitations
eject bulk modes from two boundary rows of sites, thereby dividing the
antiferromagnet into two regions with different dominant excitations. As a
result absolute values of nearest-neighbor spin correlations on the edge exceed
the bulk value.",0912.4958v1
2010-02-23,Planar Dirac diffusion,"We present the results of the planar diffusion of a Dirac particle by step
and barrier potentials, when the incoming wave impinges at an arbitrary angle
with the potential. Except for right-angle incidence this process is
characterized by the appearance of spin flip terms. For the step potential,
spin flip occurs for both transmitted and reflected waves. However, we find no
spin flip in the transmitted barrier result. This is surprising because the
barrier result may be derived directly from a two-step calculation. We
demonstrate that the spin flip cancellation indeed occurs for each particle
(wave packet) contribution.",1002.4324v1
2010-08-11,"Chirality, charge and spin-density wave instabilities of a two-dimensional electron gas in the presence of Rashba spin-orbit coupling","We show that a result equivalent to Overhauser's famous Hartree-Fock
instability theorem can be established for the case of a two-dimensional
electron gas in the presence of Rashba spin-obit coupling. In this case it is
the spatially homogeneous paramagnetic chiral ground state that is shown to be
differentially unstable with respect to a certain class of distortions of the
spin-density-wave and charge-density-wave type. The result holds for all
densities. Basic properties of these inhomogeneous states are analyzed.",1008.1816v1
2010-09-15,Anomalous High-Energy Spin Excitations in La2CuO4,"Inelastic neutron scattering is used to investigate the collective magnetic
excitations of the high-temperature superconductor parent antiferromagnet
La2CuO4. We find that while the lower energy excitations are well described by
spin-wave theory, including one- and two-magnon scattering processes, the
high-energy spin waves are strongly damped near the (1/2,0) position in
reciprocal space and merge into a momentum dependent continuum. This anomalous
damping indicates the decay of spin waves into other excitations, possibly
unbound spinon pairs.",1009.2915v1
2011-12-16,Guiding and Trapping Electron Spin Waves in Atomic Hydrogen Gas,"We present a high magnetic field study of electron spin waves in atomic
hydrogen gas compressed to high densities of 10^18 cm^-3 at temperatures
ranging from 0.26 to 0.6 K. We observed a variety of spin wave modes caused by
the identical spin rotation effect with strong dependence on the spatial
profile of the polarizing magnetic field. We demonstrate confinement of these
modes in regions of strong magnetic field and manipulate their spatial
distribution by changing the position of the field maximum.",1112.3775v3
2014-12-11,Magnetic field induced spin-wave energy focusing,"Spin waves can transport both energy and angular momentum over long distances
as they propagate. However, due to damping, their amplitude decreases
exponentially as they move away from the source, leaving little capability for
manipulating how much energy and angular momentum is to be delivered where.
Here we show that a suitable local reduction of the effective field can lead to
a large accumulation of spin wave energy far from the source. Moreover, both
the location and the amount of energy to be delivered can be controlled
accurately with geometry and externalm magnetic fields. Thus, we put forward a
general, robust and flexible approach to convey both heat and spin in
ferromagnets, which can be directly used in spintronic devices.",1412.4129v1
2015-05-27,Acoustic waves generated by the spin precession,"We study generation of acoustic waves by a precessing spin of a nanoparticle
deposited on the surface of a solid. Our approach elucidates macroscopic
dynamics of the Einstein - de Haas effect. It is based upon solution of
parameter-free equations of motion mandated by the conservation of the total
angular momentum: spin + mechanical. We show that the amplitude of the acoustic
waves generated by the spin precession may be sufficient for detection by a
tunneling electron microscope.",1505.07373v1
2016-05-12,Transmission of spin waves in ordered FeRh epitaxial thin films,"We report on B2-ordering dependence of magnetostatic surface spin waves in
ferromagnetic FeRh at room temperature. Spin waves transmit over a distance
longer than 21 {\mu}m in highly ordered FeRh alloys even with relatively large
spin-orbit interaction. The long-range transmission likely arises from the
induced Rh moments of the ordered FeRh due to ferromagnetic exchange
interaction between Fe and Rh. The results indicate a potential of using FeRh
in spintronic and magnonic applications by integrating with other fascinating
magnetic characteristics of FeRh such as electric field induced magnetic phase
transition.",1605.03798v1
2018-06-19,Scalar Tops and Perturbed Quadrupoles: Probing Fundamental Physics with Spin-Precessing Binaries,"Parity violation in the gravitational interaction has an important impact on
fundamental observables and the evolution of the universe. We here investigate
for the first time our ability to probe the parity violating nature of the
gravitational interaction using gravitational waves from spin-precessing
binaries. Focusing on dynamical Chern-Simons gravity, we derive the
spin-precession equations, calculate the gravitational waves emitted by
spin-precessing, quasi-circular black hole binaries and estimate the level to
which the theory could be constrained with future gravitational wave
observations.",1806.07425v1
2022-07-30,Inertial spin waves in ferromagnets and antiferromagnets,"Inertial effects in spin dynamics are theoretically predicted to emerge at
ultrashort time scales, but their experimental signatures are often ambiguous.
Here, we calculate the spin-wave spectrum in ferromagnets and two-sublattice
antiferromagnets in the presence of inertial effects. It is shown how
precession and nutation spin waves hybridize with each other, leading to the
renormalization of the frequencies, the group velocities, the effective
gyromagnetic ratios and the effective damping parameters. Possible ways of
distinguishing between the signatures of inertial dynamics and similar effects
explainable within conventional models are discussed.",2208.00131v1
2022-12-29,Localized Spin-Wave Modes and Microwave Absorption in Random-Anisotropy Ferromagnets,"The theory of localized spin-wave excitations in random-anisotropy magnets
has been developed. Starting with a pure Heisenberg ferromagnet, we study the
evolution of standing spin waves in a finite-size sample towards localized
modes on increasing the strength of random anisotropy. Profiles of the
localized modes and their phases are analyzed and visualized in a 2D sample.
Localization length is obtained by several methods and its dependence on random
anisotropy is computed. The connection between the localization of spin
excitations and the broadband nature of the absorption of microwave power by
random-anisotropy magnets is elucidated.",2212.14301v1
2004-08-05,Spectroscopy of spontaneous spin noise as a probe of spin dynamics and magnetic resonance,"Not all noise in experimental measurements is unwelcome. Certain fundamental
noise sources contain valuable information about the system itself -- a notable
example being the inherent voltage fluctuations that exist across any resistor
(Johnson noise), from which temperature may be determined[1,2]. In magnetic
systems, fundamental noise can exist in the form of random spin
fluctuations[3,4]. Felix Bloch noted in 1946 that statistical fluctuations of N
paramagnetic spins should generate measurable noise of order \sqrt{N} spins,
even in zero magnetic field[5,6]. Here we address precisely these same spin
fluctuations, using off-resonant Faraday rotation to passively[7,8] ""listen"" to
the magnetization noise in an equilibrium ensemble of paramagnetic alkali
atoms. These random fluctuations generate spontaneous spin coherences which
precess and decay with the same characteristic energy and time scales as the
macroscopic magnetization of an intentionally polarized or driven ensemble.
Correlation spectra of the measured spin noise reveals g-factors, nuclear spin,
isotope abundance ratios, hyperfine splittings, nuclear moments, and spin
coherence lifetimes -- without having to excite, optically pump, or otherwise
drive the system away from thermal equilibrium. These noise signatures scale
inversely with interaction volume, suggesting routes towards non-perturbative,
sourceless magnetic resonance of small systems.",0408107v1
2012-11-25,Ambient Nanoscale Sensing with Single Spins Using Quantum Decoherence,"Magnetic resonance detection is one of the most important tools used in
life-sciences today. However, as the technique detects the magnetization of
large ensembles of spins it is fundamentally limited in spatial resolution to
mesoscopic scales. Here we detect the natural fluctuations of nanoscale spin
ensembles at ambient temperatures by measuring the decoherence rate of a single
quantum spin in response to introduced extrinsic target spins. In our
experiments 45 nm nanodiamonds with single nitrogen-vacancy (NV) spins were
immersed in solution containing spin 5/2 Mn^2+ ions and the NV decoherence rate
measured though optically detected magnetic resonance. The presence of both
freely moving and accreted Mn spins in solution were detected via significant
changes in measured NV decoherence rates. Analysis of the data using a quantum
cluster expansion treatment of the NV-target system found the measurements to
be consistent with the detection of ~2,500 motionally diffusing Mn spins over
an effective volume of (16 nm)^3 in 4.2 s, representing a reduction in target
ensemble size and acquisition time of several orders of magnitude over
state-of-the-art electron spin resonance detection. These measurements provide
the basis for the detection of nanoscale magnetic field fluctuations with
unprecedented sensitivity and resolution in ambient conditions.",1211.5749v1
2013-02-12,Induction-Detection Electron Spin Resonance with Sensitivity of 1000 Spins: En Route to Scalable Quantum Computations,"Spin-based quantum computation (QC) in the solid state is considered to be
one of the most promising approaches to scalable quantum computers. However, it
faces problems such as initializing the spins, selectively addressing and
manipulating single spins, and reading out the state of the individual spins.
We have recently sketched a scheme that potentially solves all of these
problems5. This is achieved by making use of a unique phosphorus-doped 28Si
sample (28Si:P), and applying powerful new electron spin resonance (ESR)
techniques for parallel excitation, detection, and imaging in order to
implement QCs and efficiently obtain their results. The beauty of our proposed
scheme is that, contrary to other approaches, single-spin detection sensitivity
is not required and a capability to measure signals of ~100-1000 spins is
sufficient to implement it. Here we take the first experimental step towards
the actual implementation of such scheme. We show that, by making use of the
smallest ESR resonator constructed to date (~5 microns), together with a unique
cryogenic amplification scheme and sub-micron imaging capabilities, a
sensitivity of less than 1000 electron spin is obtained with spatial resolution
of ~500 nm. This is the most sensitive induction-detection experiment carried
out to date, and such capabilities put this approach on the fast track to the
demonstration of a scalable QC capability.",1302.2891v1
2013-04-30,"Nuclear-electronic spin systems, magnetic resonance, and quantum information processing","A promising platform for quantum information processing is that of silicon
impurities, where the quantum states are manipulated by magnetic resonance.
Such systems, in abstraction, can be considered as a nucleus of arbitrary spin
coupled to an electron of spin one-half via an isotropic hyperfine interaction.
We therefore refer to them as ""nuclear-electronic spin systems"". The
traditional example, being subject to intensive experimental studies, is that
of phosphorus doped silicon (Si:P) which couples a spin one-half electron to a
nucleus of the same spin, with a hyperfine strength of 117.5 MHz. More
recently, bismuth doped silicon (Si:Bi) has been suggested as an alternative
instantiation of nuclear-electronic spin systems, differing from Si:P by its
larger nuclear spin and hyperfine strength of 9/2 and 1.4754 GHz respectively.
The aim of this thesis has been to develop a model that is capable of
predicting the magnetic resonance properties of nuclear-electronic spin
systems. The theoretical predictions of this model have been tested against
experimental data collected on Si:Bi at 4.044 GHz, and have proven quite
successful. Furthermore, the larger nuclear spin and hyperfine strength of
Si:Bi, compared with that of Si:P, are predicted to offer advantages for
quantum information processing. Most notable amongst these is that magnetic
field-dependent two-dimensional decoherence free subspaces, called optimal
working points, have been identified to exist in Si:Bi, but not Si:P.",1305.0039v2
2015-03-26,Spin-orbit interaction in bent carbon nanotubes: resonant spin transitions,"We develop an effective tight-binding Hamiltonian for spin-orbit (SO)
interaction in bent carbon nanotubes (CNT) for the electrons forming the $\pi$
bonds between the nearest neighbor atoms. We account for the bend of the CNT
and the intrinsic spin-orbit interaction which introduce mixing of $\pi$ and
$\sigma$ bonds between the $p_z$ orbitals along the CNT. The effect contributes
to the main origin of the SO coupling--the folding of the graphene plane into
the nanotube. We discuss the bend-related contribution of the SO coupling for
resonant single-electron spin and charge transitions in a double quantum dot.
We report that although the effect of the bend-related SO coupling is weak for
the energy spectra, it produces a pronounced increase of the spin transition
rates driven by an external electric field. We find that spin-flipping
transitions driven by alternate electric fields have usually larger rates when
accompanied by charge shift from one dot to the other. Spin-flipping transition
rates are non-monotonic functions of the driving amplitude since they are
masked by stronger spin-conserving charge transitions. We demonstrate that the
fractional resonances--counterparts of multiphoton transitions for atoms in
strong laser fields--occurring in electrically controlled nanodevices already
at moderate ac amplitudes--can be used to maintain the spin-flip transitions.",1503.07764v2
2015-08-09,Dynamic detection of electron spin accumulation in ferromagnet-semiconductor devices by ferromagnetic resonance,"A distinguishing feature of spin accumulation in ferromagnet-semiconductor
devices is precession of the non-equilibrium spin population of the
semiconductor in a magnetic field. This is the basis for detection techniques
such as the Hanle effect, but these approaches become less effective as the
spin lifetime in the semiconductor decreases. For this reason, no electrical
Hanle measurement has been demonstrated in GaAs at room temperature. We show
here that by forcing the magnetization in the ferromagnet (the spin injector
and detector) to precess at the ferromagnetic resonance frequency, an
electrically generated spin accumulation can be detected from 30 to 300 K. At
low temperatures, the distinct Larmor precession of the spin accumulation in
the semiconductor can be detected by ferromagnetic resonance in an oblique
field. We verify the effectiveness of this new spin detection technique by
comparing the injection bias and temperature dependence of the measured spin
signal to the results obtained using traditional methods. We further show that
this new approach enables a measurement of short spin lifetimes (< 100 psec), a
regime that is not accessible in semiconductors using traditional Hanle
techniques.",1508.02093v1
2021-08-02,Quantum Computation Protocol for Dressed Spins in a Global Field,"Spin qubits are contenders for scalable quantum computation because of their
long coherence times demonstrated in a variety of materials, but individual
control by frequency-selective addressing using pulsed spin resonance creates
severe technical challenges for scaling up to many qubits. This individual
resonance control strategy requires each spin to have a distinguishable
frequency, imposing a maximum number of spins that can be individually driven
before qubit crosstalk becomes unavoidable. Here we describe a complete
strategy for controlling a large array of spins in quantum dots dressed by an
on-resonance global field, namely a field that is constantly driving the spin
qubits, to dynamically decouple from the effects of background magnetic field
fluctuations. This approach -- previously implemented for the control of single
electron spins bound to electrons in impurities -- is here harmonized with all
other operations necessary for universal quantum computing with spins in
quantum dots. We define the logical states as the dressed qubit states and
discuss initialization and readout utilizing Pauli spin blockade, as well as
single- and two-qubit control in the new basis. Finally, we critically analyze
the limitations imposed by qubit variability and potential strategies to
improve performance.",2108.00798v2
2021-02-28,Spin and charge interconversion in Dirac semimetal thin films,"We report spin-to-charge and charge-to-spin conversion at room temperature in
heterostructure devices that interface an archetypal Dirac semimetal, Cd3As2,
with a metallic ferromagnet, Ni0.80Fe0.20 (permalloy). The spin-charge
interconversion is detected by both spin torque ferromagnetic resonance and
ferromagnetic resonance driven spin pumping. Analysis of the symmetric and
anti-symmetric components of the mixing voltage in spin torque ferromagnetic
resonance and the frequency and power dependence of the spin pumping signal
show that the behavior of these processes is consistent with previously
reported spin-charge interconversion mechanisms in heavy metals, topological
insulators, and Weyl semimetals. We find that the efficiency of spin-charge
interconversion in Cd3As2/permalloy bilayers can be comparable to that in heavy
metals. We discuss the underlying mechanisms by comparing our results with
first principles calculations.",2103.00653v1
2021-10-05,Role of the high-spin nucleon and delta resonances in the $KΛ$ and $KΣ$ photoproduction off the nucleon,"We have investigated the effect of nucleon and delta resonances with spins
11/2, 13/2, and 15/2 in the kaon photoproduction process $\gamma + N \to K + Y$
by using two covariant isobar models. The formalism for high-spin propagators
and interaction Lagrangians were adopted from the works of Pascalutsa and
Vrancx et al. The unknown parameters in the amplitudes, i.e., the coupling
constants and hadronic form factor cutoffs, were obtained by fitting the
calculated observables to experimental data. In the $K\Lambda$ channels the
inclusion of $N(2600)I_{1,11}$ and $N(2700)K_{1,13}$ resonances improves the
agreement between model calculations and experimental data significantly and
reduces the dominance of resonances in the model by increasing the hadronic
form factor cutoff of the Born terms. Furthermore, the inclusion of these
resonances reduces the number of resonance structures in cross sections,
including the structure in the $K^0\Lambda$ differential cross section at
$W\approx 1650$ MeV, which could become a hint of the narrow resonance. In the
$K\Sigma$ channels the inclusion of $N(2600)I_{1,11}$, $N(2700)K_{1,13}$,
$\Delta(2420)H_{3,11}$, $\Delta(2750)I_{3,13}$, and $\Delta(2950)K_{3,15}$
states also significantly improves the model and increases the hadronic form
factor cutoff of the Born terms. However, different from the $K\Lambda$
channels, the inclusion of these high-spin resonances leads to more resonance
structures in the $K^+\Sigma^0$ differential cross section. This investigation
reveals that the second and third peaks in the $K^+\Sigma^0$ differential cross
section originate from the $\Delta(2000)F_{35}$ and $N(2290)G_{19}$ resonances,
respectively. We have also evaluated the resonance properties at the pole
positions and using the Breit-Wigner method.",2110.01789v1
1998-09-16,The effective Hamiltonian of the Pound-Overhauser controlled-NOT gate,"In NMR-based quantum computing, it is known that the controlled-NOT gate can
be implemented by applying a low-power, monochromatic radio-frequency field to
one peak of a doublet in a weakly-coupled two-spin system. This is known in NMR
spectroscopy as Pound-Overhauser double resonance. The ``transition''
Hamiltonian that has been associated with this procedure is however only an
approximation, which ignores off-resonance effects and does not correctly
predict the associated phase factors. In this paper, the exact effective
Hamiltonian for evolution of the spins' state in a rotating frame is derived,
both under irradiation of a single peak (on-transition) as well as between the
peaks of the doublet (on-resonance). The accuracy of these effective
Hamiltonians is validated by comparing the observable product operator
components of the density matrix obtained by simulation to those obtained by
fitting the corresponding experiments. It is further shown how both the
on-transition and on-resonance fields can be used to implement the
controlled-NOT gate exactly up to conditional phases, and analytic expressions
for these phases are derived. In Appendices, the on-resonance Hamiltonian is
analytically diagonalized, and proofs are given that, in the weak-coupling
approximation, off-resonance effects can be neglected whenever the
radio-frequency field power is small compared to the difference in resonance
frequencies of the two spins.",9809045v1
2017-02-07,Possible hundredfold enhancement in the direct magnetic coupling of a single atomic spin to a circuit resonator,"We report on the challenges and limitations of direct coupling of the
magnetic field from a circuit resonator to an electron spin bound to a donor
potential. We propose a device consisting of a trilayer lumped-element
superconducting resonator and a single donor implanted in enriched $^{28}$Si.
The resonator impedance is significantly smaller than the practically
achievable limit using prevalent coplanar resonators. Furthermore, the
resonator includes a nano-scale spiral inductor to spatially focus the magnetic
field from the photons at the location of the implanted donor. The design
promises approximately two orders of magnitude increase in the local magnetic
field, and thus the spin to photon coupling rate $g$, compared to the estimated
coupling rate to the magnetic field of coplanar transmission-line resonators.
We show that by using niobium (aluminum) as the resonator's superconductor and
a single phosphorous (bismuth) atom as the donor, a coupling rate of
$g/2\pi$=0.24 MHz (0.39 MHz) can be achieved in the single photon regime. For
this hybrid cavity quantum electrodynamic system, such enhancement in $g$ is
sufficient to enter the strong coupling regime.",1702.02210v3
2020-05-26,Dynamical History of the Uranian System,"We numerically simulate the past tidal evolution of the five large moons of
Uranus (Miranda, Ariel, Umbriel, Titania, and Oberon). We find that the most
recent major mean-motion resonance (MMR) between any two moons, the
Ariel-Umbriel 5:3 MMR, had a large effect on the whole system. Our results
suggest that this resonance is responsible for the current 4.3$^{\circ}$
inclination of Miranda (instead of previously proposed 3:1 Miranda-Umbriel
MMR), and that all five moons had their inclinations excited during this
resonance. Miranda experienced significant tidal heating during the
Ariel-Umbriel 5:3 MMR due to its eccentricity being excited by Ariel's secular
perturbations. This tidal heating draws energy from shrinking of Miranda's
orbit, rather than Ariel's outward evolution, and can generate heat flows in
excess of 100 mW m$^{-2}$, sufficient to produce young coronae on Miranda. We
find that this MMR was followed by a sequence of secular resonances, which
reshuffled the moons' eccentricities and inclinations. We also find that the
precession of Oberon's spin axis is close to a resonance with the precession of
Umbriel's orbital plane, and that this spin-orbit resonance was likely excited
during the Ariel-Umbriel 5:3 MMR. After the exit from the MMR, subsequent
Ariel-Umbriel secular resonance and Oberon-Umbriel spin-orbit resonance may be
able to explain the current low inclinations of Ariel and Umbriel. The age of
Miranda's surface features tentatively suggests Uranian tidal
$Q=15,000-20,000$, which can be further refined in future work.",2005.12887v1
2004-04-14,Spin-orbit entanglement in time evolution of radial wave packets in hydrogenic systems,"Time evolution of radial wave packets built from the eigenstates of Dirac
equation for a hydrogenic systems is considered. Radial wave packets are
constructed from the states of different $n$ quantum number and the same lowest
angular momentum. In general they exhibit a kind of breathing motion with
dispersion and (partial) revivals. Calculations show that for some particular
preparations of the wave packet one can observe interesting effects in spin
motion, coming from inherent entanglement of spin and orbital degrees of
freedom. These effects manifest themselves through some oscillations in the
mean values of spin operators and through changes of spatial probability
density carried by upper and lower components of the wave function. It is also
shown that the characteristic time scale of predicted effects (called
$T_{\mathrm{ls}}$) is for radial wave packets much smaller than in other cases,
reaching values comparable to (or even less than) the time scale for the wave
packet revival.",0404084v1
2008-04-07,Phase reciprocity of spin-wave excitation by a microstrip antenna,"Using space-, time- and phase-resolved Brillouin light scattering
spectroscopy we investigate the difference in phase of the two
counterpropagating spin waves excited by the same microwave microstrip
transducer. These studies are performed both for backward volume magnetostatic
waves and magnetostatic surface waves in an in-plane magnetized yttrium iron
garnet film. The experiments show that for the backward volume magnetostatic
spin waves (which are reciprocal and excited symmetrically in amplitude) there
is a phase difference of $\pi$ associated with the excitation process and thus
the phase symmetry is distorted. On the contrary, for the magnetostatic surface
spin waves (which are non-reciprocal and unsymmetrical in amplitude) the phase
symmetry is preserved (there is no phase difference between the two waves
associated with the excitation). Theoretical analysis confirms this effect.",0804.1090v1
2015-11-30,Frequency non-reciprocity of surface spin wave in Permalloy thin films,"Surface spin waves in thin Permalloy films are studied by means of
propagative spin wave spectroscopy. We observe a systematic difference of up to
several tens of MHz when comparing the frequencies of counter-propagating
waves. This frequency non-reciprocity effect is modeled using an analytical
dipole-exchange theory that considers the mutual influence of non-reciprocal
spin wave modal profiles and differences in magnetic anisotropies at the two
film surfaces. At moderate film thickness (20 nm and below), the frequency
non-reciprocity scales linearly with the wave vector and quadratically with the
thickness, whereas a more complex non-monotonic behavior is observed at larger
thickness. Our work suggests that surface wave frequency non-reciprocity can be
used as an accurate spectroscopic probe of magnetic asymmetries in thin
ferromagnetic films.",1511.09351v1
2019-05-20,Topological characterization of classical waves: the topological origin of magnetostatic surface spin waves,"We propose a topological characterization of Hamiltonians describing
classical waves. Applying it to the magnetostatic surface spin waves that are
important in spintronics applications, we settle the speculation over their
topological origin. For a class of classical systems that includes spin waves
driven by dipole-dipole interactions, we show that the topology is
characterized by vortex lines in the Brillouin zone in such a way that the
symplectic structure of Hamiltonian mechanics plays an essential role. We
define winding numbers around these vortex lines and identify them to be the
bulk topological invariants for a class of semimetals. Exploiting the bulk-edge
correspondence appropriately reformulated for these classical waves, we predict
that surface modes appear but not in a gap of the bulk frequency spectrum. This
feature, consistent with the magnetostatic surface spin waves, indicates a
broader realm of topological phases of matter beyond spectrally gapped ones.",1905.07909v1
2017-03-09,Overcoming thermal noise in non-volatile spin wave logic,"Spin waves are propagating disturbances in magnetically ordered materials,
analogous to lattice waves in solid systems and are often described from a
quasiparticle point of view as magnons. The attractive advantages of
Joule-heat-free transmission of information, utilization of the phase of the
wave as an additional degree of freedom and lower footprint area compared to
conventional charge-based devices have made spin waves or magnon spintronics a
promising candidate for beyond-CMOS wave-based computation. However, any
practical realization of an all-magnon based computing system must undergo the
essential steps of a careful selection of materials and demonstrate robustness
with respect to thermal noise or variability. Here, we aim at identifying
suitable materials and theoretically demonstrate the possibility of achieving
error-free clocked non-volatile spin wave logic device, even in the presence of
thermal noise and clock jitter or clock skew.",1703.03460v2
2022-04-15,Experimental Visualization of Dispersion Characteristics of Backward Volume Spin Wave Modes,"Basing on the measurement of spatial spectra (spectra of wavenumbers), the
dispersion characteristics of the first three modes of backward volume spin
wave, propagating along the direction of a constant uniform magnetic field in a
tangentially magnetized ferrite film, were visualized firstly. The study was
carried out by microwave probing of spin waves with subsequent use of spatial
Fourier analysis of the complex wave amplitude for a series of frequencies. It
was found that every m-th mode of the backward volume spins wave can be split
into n satellite modes due to the existence of layers with similar magnetic
parameters in ferrite film. It was found that satellites of the first mode of
this wave are excited most effectively, while satellites of the third mode -
least effectively, and the effectiveness of satellites excitation decreases as
the number n increases. It is found that the theoretical dispersion
dependencies of the first three modes of the wave coincide well with the
experimental dispersion dependencies of the satellite mode that are excited
most effectively.",2204.08293v1
2024-02-18,Double-$Q$ and quadruple-$Q$ instabilities at low-symmetric ordering wave vectors under tetragonal symmetry,"Multiple-$Q$ states are expressed as a superposition of spin density waves at
multiple ordering wave vectors, which results in unconventional complicated
spin textures, such as skyrmion, hedgehog, and vortex. We investigate the
multiple-$Q$ instability by focusing on the low-symmetric ordering wave vectors
in momentum space. By systematically performing the simulated annealing for
effective spin models with various ordering wave vectors on a two-dimensional
square lattice, we classify the magnetic phase diagram into four types
according to the position of the ordering wave vectors. Three out of four cases
lead to a plethora of isotropic multiple-$Q$ instabilities yielding collinear,
coplanar, and noncoplanar double-$Q$ and quadruple-$Q$ magnetic phases, while
the remaining case leads to an anisotropic double-$Q$ instability when the
multiple-spin interaction is introduced. Our results indicate that exotic
multiple-$Q$ phases distinct from the skyrmion crystal phase are expected when
the ordering wave vectors lie on the low-symmetric positions in the Brillouin
zone.",2402.11721v1
2014-02-06,Alfvén Wave Driven High Frequency Waves in the Solar Atmosphere: Implications for Ion Heating,"This work is an extension of Kaghashvili [1999] where ion-cyclotron wave
dissipation channel for Alfv\'en waves was discussed. While our earlier study
dealt with the mode coupling in the commonly discussed sense, here we study
changes in the initial waveform due to interaction of the initial driver
Alfv\'en wave and the plasma inhomogeneity, which are implicitly present in the
equations, but were not elaborated in Kaghashvili [1999]. Using a cold plasma
approximation, we show how high frequency waves (higher than the initial driver
Alfv\'en wave frequency) are generated in the inhomogeneous solar plasma flow.
The generation of the high frequency forward and backward propagating modified
fast magnetosonic/whistler waves as well as the generation of the driven
Alfv\'en waves is discussed in the solar atmosphere. The generated high
frequency waves have a shorter dissipation timescale, and they can also
resonant interact with particles using both the normal cyclotron and anomalous
cyclotron interaction channels. These waves can also be important in space,
Earths magnetosphere, the ionosphere, and laboratory plasma processes.",1402.1518v1
2016-09-08,Harmonics Effect on Ion-Bulk Waves in CH Plasmas,"The harmonics effect on ion-bulk (IBk) waves has been researched by Vlasov
simulation. The condition of excitation of a large-amplitude IBk waves is given
to explain the phenomenon of strong short-wavelength electrostatic activity in
solar wind. When $k$ is much lower than $k_{lor}/2$ ($k_{lor}$ is the wave
number at loss-of-resonance point), the IBk waves will not be excited to a
large amplitude, because a large part of energy will be spread to harmonics.
The nature of nonlinear IBk waves in the condition of $k<k_{lor}/2$ is undamped
Bernstein-Greene-Kruskal-like waves with harmonics superposition. Only when the
wave number $k$ of IBk waves satisfies $k_{lor}/2\lesssim k\leq k_{lor}$, can a
large-amplitude and mono-frequency IBk wave be excited. These results give a
guidance for a novel scattering mechanism related to IBk waves in the field of
laser plasma interaction.",1609.02280v1
2017-08-12,Effects of equatorial chorus wave normal azimuthal distribution on wave propagation,"The non-ducted propagation characteristics of the VLF waves in the inner
magnetosphere were studied with respect to their frequency, source
localization, and initial wave normal angle, between the wave-normal and the
background magnetic field. The ray tracing software based on multi-components
cold plasma approach was developed by use of the IGRF magnetic field model and
the GCPM model of plasma density. We described dynamics of the wave-normals
direction during its propagation and magnetospheric reflection. We showed that
whistler waves can be reflected when lower hybrid resonance frequency becomes
greater than the wave frequency: w_LH>w. It corresponds to the magnetic
latitude of ~50 degrees. The simulation results confirmed the inapplicability
of the quasi-longitudinal approximation to describe the propagation of
magnetospheric whistlers. The simulation results of chorus emissions
propagation, which used realistic distributions of waves on the initial
parameters were presented. Particularly, we obtained distributions of chorus
emission waves in dependence on the wave-normal directions for different
magnetic latitudes. It is required for studying diffusive processes in the
radiation belts. The results were found to be in a good agreement with the
CLUSTER STAFF-SA measurements.",1708.03819v1
2019-08-17,Non-spreading matter-wave packets in a ring,"Non-spreading wave packets and matter-wave packets in ring traps both have
attracted great research interests due to their miraculous physical properties
and tempting applications for quite a long time. Here, we proved that there
exists only one set of non-spreading matter-wave packets in a free ring, and
this set of wave packets have been found analytically. These non-spreading
matter-wave packets can be realized in a toroidal trapped Bose-Einstein
condensate system with the help of Feshbach resonance to eliminate contact
interaction between atoms. Since experimentally residual interaction noise will
always exist, its effect on the stability of these non-spreading wave packets
is also examined. Qualitatively, under weak residual interaction noise, these
non-spreading wave packets can preserve their shape for quite a long time,
while a stronger interaction noise will induce shape breathing of the wave
packets. Shape-keeping abilities of these wave packets are further studied
quantitatively. We found that this set of wave packets have the same
shape-keeping ability against interaction noise. And, the shape-keeping ability
is linearly related to the interaction noise strength.",1908.06285v1
2022-05-01,Large mode-2 internal solitary waves in three-layer flows,"In this paper, we investigate mode-2 solitary waves in a three-layer
stratified flow model. Localised travelling wave solutions to both the fully
nonlinear problem (Euler equations), and the three-layer Miyata-Choi-Camassa
equations are found numerically and compared. Mode-2 solitary waves with speeds
slower than the linear mode-1 long-wave speed are typically generalised
solitary waves with infinite tails consisting of a resonant mode-one periodic
wave train. Herein we evidence the existence of mode-2 embedded solitary waves,
that is, we show that for specific values of the parameters, the amplitude of
the oscillations in the tail are zero. For sufficiently thick middle layers, we
also find branches of mode-2 solitary waves with speeds that extend beyond the
mode-1 linear waves and are no longer embedded. In addition, we show how large
amplitude embedded solitary waves are intimately linked to the conjugate states
of the problem.",2205.00503v2
2023-11-28,The Hoyle and associated excited states from the viewpoint of pocket resonances in alpha + 8Be reactions,"We examine the production of the Hoyle and associated excited states from the
viewpoint of pocket resonances in the reaction of an $\alpha$-particle on a
ground state prolate $^8$Be nucleus within the optical model coupled-channel
framework. The predicted reaction cross sections, as a function of the
center-of-mass energy $E_{\rm cm}$, show prominent resonances, including the
Hoyle resonance. The positions and widths of these resonances are sensitive to
the target deformation ($\beta_2$ parameter) and the parity of the nuclear
surface potential $-$ deeper for the even-parity $L$ partial waves relative to
those for the odd-parity $L$ partial waves at the surface region because of the
Bose-Einstein exchange of the $\alpha$-bosons. Decomposing the reaction cross
sections to different partial waves, we find that the resonance energies and
widths reasonably agree with the available experimental data and previous
hyperspherical calculations for the $0_2^+$ (Hoyle state), $0_3^+$, $1_1^-$ and
$3_1^-$ states of $^{12}$C, except for the narrow theoretical width of the
$2_2^+$ state. Analyzing the wavefunctions and the resonance widths, we
identify the narrow and sharp $0_2^+$, $3_1^-$ and $2_2^+$ resonances as pocket
resonances -- resonances which occur below the potential barrier, while the
broad $0_3^+$ and $1_1^-$ resonances as above-the-barrier resonances. For
astrophysical applications, we also evaluate the astrophysical $S(E_{\rm
cm})$-factor for $E_{\rm cm}$ $<$ 1.0 MeV, for the fusion of $\alpha$+$^8$Be
into the $^{12}$C$(2^+)$ state based on our estimated $s$-wave $\alpha$+$^8$Be
reaction cross section and the associated $\gamma$- and $\alpha$-decay widths
for the decay of $^{12}$C excited states in the potential pocket.",2311.16837v1
2010-08-19,Gravitational Radiations from a Spinning Compact Object around a supermassive Kerr black hole in circular orbit,"The gravitational waves and energy radiations from a spinning compact object
with stellar mass in a circular orbit in the equatorial plane of a supermassive
Kerr black hole are investigated in this paper. The effect how the spin acts on
energy and angular moment fluxes is discussed in detail. The calculation
results indicate that the spin of small body should be considered in
waveform-template production for the upcoming gravitational wave detections. It
is clear that when the direction of spin axes is the same as the orbitally
angular momentum (""positive"" spin), spin can decrease the energy fluxes which
radiate to infinity. For antidirection spin (""negative""), the energy fluxes to
infinity can be enlarged. And the relations between fluxes (both infinity and
horizon) and spin look like quadratic functions. From frequency shift due to
spin, we estimate the wave-phase accumulation during the inspiraling process of
the particle. We find that the time of particle inspiral into the black hole is
longer for positive spin and shorter for negative compared with the nonspinning
particle. Especially, for extreme spin value, the energy radiation near the
horizon of the extreme Kerr black hole is much more than that for the
nonspinning one. And consequently, the maximum binging energy of the extreme
spinning particle is much larger than that of the nonspinning particle.",1008.3324v3
2001-12-19,A non-linear theory of vertical resonances in accretion discs,"An important and widely neglected aspect of the interaction between an
accretion disc and a massive companion with a coplanar orbit is the vertical
component of the tidal force. As shown by Lubow, the response of the disc to
vertical forcing is resonant at certain radii, at which a localized torque is
exerted, and from which a compressive wave (p mode) may be emitted. Although
these vertical resonances are weaker than the corresponding Lindblad
resonances, the m=2 inner vertical resonance in a binary star is typically
located within the tidal truncation radius of a circumstellar disc.
  In this paper I develop a general theory of vertical resonances, allowing for
non-linearity of the response, and dissipation by radiative damping and
turbulent viscosity. The problem is reduced to a universal, non-linear ordinary
differential equation with two real parameters. Solutions of the complex
non-linear Airy equation are presented to illustrate the non-linear saturation
of the resonance and the effects of dissipation. It is argued that the m=2
inner vertical resonance is unlikely to truncate the disc in cataclysmic
variable stars, but contributes to angular momentum transport and produces a
potentially observable non-axisymmetric structure.",0112443v1
2006-05-18,Resonant Relaxation near the Massive Black Hole in the Galactic Center,"The coherent torques between stars on orbits near massive black holes (MBHs)
lead to resonant angular momentum relaxation. Due to the fact that orbits are
Keplerian to good approximation, the torques efficiently change the magnitude
of the angular momenta and rotate the orbital inclinations. As a result the
stars are rapidly randomized. The galactic MBH is a good system for the
observational study of resonant relaxation. The age of the young B-stars at a
distance of $\sim0.01 pc$ from the MBH is comparable to the resonant relaxation
time, implying that resonant relaxation may have played an important role in
their dynamical structure. In contrast, the O-stars in the stellar disks at
$\sim0.1 pc$ are younger than the resonant relaxation time, as required by
their dynamical coherence. Resonant relaxation dynamics dominates the event
rate of gravitational wave (GW) emission from inspiraling stars into MBHs of
masses comparable to the Galactic MBH. Resonant relaxation leads to rates
$\lesssim 10$ times higher than those predicted by 2-body relaxation, which
would improve the prospects of detecting these events by future GW detectors,
such as LISA.",0605457v1
2009-05-31,The impact of local resonance on the enhanced transmission and dispersion of surface resonances,"We investigate the enhanced microwave transmission through the array of
metallic coaxial annular apertures (MCAAs) experimentally and theoretically.
The even-mode and the odd-mode surface resonances are clarified from the
spatial field distributions and the dispersion diagram. The impact of local
resonance is thoroughly embodied in the even-mode surface resonant states,
while the odd-mode surface resonances are scaled by periodicity, invariant to
different local geometry of the unit cell, and invisible in measurements. The
enhanced transmission is the collective selections on the interplay between the
local resonances and the evanescent Bloch wave channels on the surface.
Transmission measurements for different inner diameter of the apertures show
that the transmissivity extrema with respect to the specific angles precisely
correspond to the degenerate points in the dispersion diagram of surface
resonances.",0906.0128v1
2011-10-12,Giant red shift and enhancement of resonant light confinement in planar array of dielectric bars,"Results of research of resonant phenomena in planar periodic structures
consisted of dielectric elements are presented. A problem of plane wave
diffraction by a structure which a periodic cell is composed of two dielectric
bars with different lengths has been solved. For the first time an existence of
high Q-factor trapped mode resonances are revealed in these structures. The
main difference of studied structure in contrast to the planar structure with a
single dielectric bar in the unit cell is appearing of a great red shift of a
trapped mode resonant wavelength. The red shift is caused by strong coupling of
electromagnetic fields in neighbor dielectric bar resonators. This property is
very attractive to design resonant periodic planar structures by using moderate
refractive index materials like semiconductors within their transparency
window. In the near infrared band, the trapped mode resonances of periodic
planar structure with bars made of germanium have been studied. It is shown
that decreasing of structure asymmetry degree results in increasing of both red
shift and Q-factor of resonance.",1110.2699v2
2012-07-01,Observation of two new $N^*$ resonances in $ψ(3686) \rightarrow p\bar{p}π^0$,"Based on 106$\times10^6 \psi(3686)$ events collected with the BESIII detector
at the BEPCII facility, a partial wave analysis of $\psi(3686)\rightarrow
p\bar{p}\pi^0$ is performed. The branching fraction of this channel has been
determined to be $B(\psi(3686)\rightarrow p\bar{p}\pi^0) =
(1.65\pm0.03\pm0.15)\times 10^{-4}$. In this decay, 7 $N^*$ intermediate
resonances are observed. Among these $N^*$ resonances, two new resonances are
significant, one $1/2^+$ resonance with a mass of
$2300^{+40}_{-30}$$^{+109}_{-0}$ $\mathrm{MeV}/c^2$ and width of
$340^{+30}_{-30}$$^{+110}_{-58}$ $\mathrm{MeV}/c^2$, and one $5/2^-$ resonance
with a mass of $2570^{+19}_{-10}$$^{+34}_{-10}$ $\mathrm{MeV}/c^2$ and width of
$250^{+14}_{-24}$$^{+69}_{-21}$ $\mathrm{MeV}/c^2$. For the remaining 5 $N^*$
intermediate resonances, the analysis yields mass and width values which are
consistent with those from established resonances.",1207.0223v2
2014-10-24,Bound and resonance states of the dipolar anion of hydrogen cyanide: competition between threshold effects and rotation in an open quantum system,"Bound and resonance states of the dipole-bound anion of hydrogen cyanide
HCN$^-$ are studied using a non-adiabatic pseudopotential method and the
Berggren expansion technique involving bound states, decaying resonant states,
and non-resonant scattering continuum. We devise an algorithm to identify the
resonant states in the complex energy plane. To characterize spatial
distributions of electronic wave functions, we introduce the body-fixed density
and use it to assign families of resonant states into collective rotational
bands. We find that the non-adiabatic coupling of electronic motion to
molecular rotation results in a transition from the strong-coupling to
weak-coupling regime. In the strong coupling limit, the electron moving in a
subthreshold, spatially extended halo state follows the rotational motion of
the molecule. Above the ionization threshold, electron's motion in a resonance
state becomes largely decoupled from molecular rotation. Widths of
resonance-band members depend primarily on the electron orbital angular
momentum.",1410.6660v1
2014-11-06,The nucleon resonances in the $J/ψ\to p\bar{p}η'$ decay,"We are aiming to study the $J/\psi \to p\bar{p}\eta'$ decay in an isobar
model and the effective Lagrangian approach. After a careful exploration of the
contributions of the $S_{11}(1535)$, $P_{11}(1710)$, $P_{13}(1900)$,
$S_{11}(2090)$ and $P_{11}(2100)$ resonances, we conclude that either a
subthreshold resonance or a broad $P$-wave state in the near threshold range
seems to be indispensable to describe present data of the $\pi N \to \eta'N$.
Furthermore, at least one broad resonance above $\eta'N$ threshold is
preferred. With this detailed analysis, we could give the invariant mass
spectrum and Dalitz plot of the $J/\psi \to p\bar{p}\eta'$ decay for the
purpose of assisting the future detailed partial wave analysis. It is found
that the $J/\psi \to p\bar{p}\eta'$ data are useful for disentangling the above
or below threshold resonant contribution, though it still further needs the
differential cross section data of $\pi N \to \eta'N$ to realize some of the
resonant and the non-resonant contribution. Our results are enlightening for
the $\eta'N$ production mechanism and the properties of the nucleon resonances
with the mass around 2.0~GeV.",1411.1493v1
2019-11-27,"Spatial Resolution, Sensitivity and Surface Selectivity in Resonant Mode Photothermal Induced Resonance Spectroscopy","Photothermal-Induced Resonance (PTIR) is increasingly used in the measurement
of infrared absorption spectra of sub-micrometer objects. The technique
measures IR absorption spectra by relying on the photothermal effect induced by
a rapid pulse of light and the excitation of the resonance spectrum of an AFM
cantilever in contact with the sample. In this work we assess the spatial
resolution and depth response of PTIR in resonant mode while systematically
varying the pulsing frequency of the excitation laser and the cantilever
resonance. The spatial resolution shows a shallow linear dependence on the
inverse of the pulse frequency, which rules out tip size as a limiting factor
for resolution in the frequency range under investigation. Measured resolution
values are also one order of magnitude lower than in the thermal diffusion
limit, excluding thermal wave propagation as a limiting factor. We also show
that the pulsing frequency of the laser and choice of cantilever resonance
affect the intensity of the signal and the surface selectivity in PTIR images,
with higher frequencies providing increased surface selectivity. The results
confirm a difference in signal generation between resonant PTIR and other
photothermal techniques and indicate that photothermal induced heating and
expansion cannot fully account for observed intensity and resolution.",1911.12097v1
2021-12-07,Plasmon resonances of nanorods in transverse electromagnetic scattering,"Plasmon resonance is the resonant oscillation of conduction electrons at the
interface between negative and positive permittivity material stimulated by
incident light, which forms the fundamental basis of many cutting-edge
industrial applications. We are concerned with the quantitative theoretical
understanding of this peculiar resonance phenomenon. It is known that the
occurrence of plasmon resonance as well as its quantitative behaviours
critically depend on the geometry of the material structure, the corresponding
material parameters and the operating wave frequency, which are delicately
coupled together. In this paper, we study the plasmon resonance for a 2D
nanorod structure, which presents an anisotropic geometry and arises in the
transverse electromagnetic scattering. We present delicate spectral and
asymptotic analysis to establish the accurate resonant conditions as well as
sharply characterize the quantitative behaviours of the resonant field.",2112.03697v2
2022-07-29,Coherent resonant transmission,"The reflectionless coherent light transport in the coupled resonator array is
investigated in the presence of intra-resonator intermodal coupling between the
clockwise and counterclockwise modes, which plays a constructive role for
modulating the light flow rather than inducing the unwanted backscattering. The
interplay between the intra-resonator intermodal coupling and the
inter-resonator couplings enables the coherent resonant transmission (CRT) of
the properly superposed injection constituted by the clockwise and
counterclockwise modes. The superposition coefficients of the initial
excitation determine the mode chirality of the resonant transmission.
Sequentially experiencing the time-reversal process of CRT and the CRT realizes
the perfect mode conversion that the mode chirality of the injection wave
switches into the opposite after resonant transmission. Our findings on the
coherent light transport provide insights for the control and manipulation of
light field in the integrated photonics, nanophotonics, chiral optics, and
beyond.",2207.14453v1
2020-12-04,Effects of hybridization and spin-orbit coupling to induce odd frequency pairing in two-band superconductors,"The effects of spin independent hybridization potential and spin orbit
coupling on two band superconductor with equal time s-wave inter band pairing
order parameter is investigated theoretically. To study symmetry classes in two
band superconductors the Gorkov equations are solved analytically. By defining
spin singlet and spin triplet s wave order parameter due to two band degree of
freedom the symmetry classes of Cooper pair are studied. For spin singlet case
it is shown that spin independent hybridization generates Cooper pair belongs
to even frequency spin singlet even momentum even band parity (ESEE) symmetry
class for both intraband and interband pairing correlations. For spin triplet
order parameter, intraband pairing correlation generates odd frequency spin
triplet even momentum even band parity (OTEE) symmetry class whereas, interband
pairing correlation generates even frequency spin triplet even momentum odd
band parity ETEO) class. For the spin singlet, spin orbit coupling generates
pairing correlation that belongs to odd frequency spin singlet odd momentum
even band parity (OSOE) symmetry class and even frequency spin singlet even
momentum even band parity (ESEE) for intraband and interband pairing
correlation respectively. In the spin triplet case for itraband and interband
correlation, spin orbit coupling generates even-frequency spin triplet odd
momentum even band parity (ETOE) and even frequency spin triplet even momentum
odd band parity (ETEO) respectively.",2012.02810v1
1996-09-11,Cumulant approach to weakly doped antiferromagnets,"We present a new approach to static and dynamical properties of holes and
spins in weakly doped antiferromagnets in two dimensions. The calculations are
based on a recently introduced cumulant approach to ground--state properties of
correlated electronic systems. The present method allows to evaluate hole and
spin--wave dispersion relations by considering hole or spin excitations of the
ground state. Usually, these dispersions are found from time--dependent
correlation functions. To demonstrate the ability of the approach we first
derive the dispersion relation for the lowest single hole excitation at
half--filling. However, the main purpose of this paper is to focus on the
mutual influence of mobile holes and spin waves in the weakly doped system. It
is shown that low-energy spin excitations strongly admix to the ground--state.
The coupling of spin waves and holes leads to a strong suppression of the
staggered magnetization which can not be explained by a simple rigid--band
picture for the hole quasiparticles. Also the experimentally observed doping
dependence of the spin--wave excitation energies can be understood within our
formalism.",9609098v1
2005-06-21,Spin wave contribution to the nuclear spin-lattice relaxation in triplet superconductors,"We discuss collective spin wave excitations in triplet superconductors with
an easy axis anisotropy for the order parameter. Using a microscopic model for
interacting electrons we estimate the frequency of such excitations in
Bechgaard salts and ruthenate superconductors to be one and twenty GHz
respectively. We introduce an effective bosonic model to describe spin-wave
excitations and calculate their contribution to the nuclear spin lattice
relaxation rate. We find that in the experimentally relevant regime of
temperatures, this mechanism leads to the power law scaling of 1/T_1 with
temperature. For two and three dimensional systems the scaling exponents are
three and five respectively. We discuss experimental manifestations of the spin
wave mechanism of the nuclear spin lattice relaxation.",0506548v1
2008-10-27,Anisotropic itinerant magnetism and spin fluctuations in BaFe2As2: A neutron scattering study,"Neutron scattering measurements were performed to investigate magnetic
excitations in a single-crystal sample of the ternary iron arsenide BaFe2As2, a
parent compound of a recently discovered family of Fe-based superconductors. In
the ordered state, we observe low energy spin-wave excitations with a gap
energy of 9.8(4) meV. The in-plane spin-wave velocity v_ab and out-of-plane
spin-wave velocity v_c measured at 12 meV are 280(150) and 57(7) meV A,
respectively. At high energy, we observe anisotropic scattering centered at the
antiferromagnetic wave vectors. This scattering indicates two-dimensional spin
dynamics, which possibly exist inside the Stoner continuum. At T_N=136(1) K,
the gap closes, and quasi-elastic scattering is observed above T_N, indicative
of short-range spin fluctuations. In the paramagnetic state, the scattering
intensity along the L direction becomes ""rodlike,"" characteristic of
uncorrelated out-of-plane spins, attesting to the two-dimensionality of the
system.",0810.4790v2
2011-02-27,Multiorbital Spin Susceptibility in a Magnetically Ordered State - Orbital versus Excitonic Spin Density Wave Scenario,"We present a general theory of multiorbital spin waves in magnetically
ordered metallic systems. Motivated by the itinerant magnetism of iron-based
superconductors, we compare the magnetic excitations for two different
scenarios: when the magnetic order either sets in on the on-site orbital level;
or when it appears as an electron-hole pairing between different bands of
electron and hole character. As an example we treat the two-orbital model for
iron-based superconductors. For small magnetic moments the spin excitations
look similar in both scenarios. Going to larger interactions and larger
magnetic moments, the difference between both scenarios becomes striking. While
in the excitonic scenario the spin waves form a closed structure over the
entire Brillouin zone and the particle-hole continuum is gapped, the spin
excitations in the orbital scenario can be treated as spin waves only in a
close vicinity to the ordering momenta. The origin of this is a gapless
electronic structure with Dirac cones which is a source of large damping. We
analyze our results in connection with recent neutron scattering measurements
and show that certain features of the orbital scenario with multiple order
parameters can be observed experimentally.",1102.5532v1
2012-09-07,Chiral Spin Waves in Fermi Liquids with Spin-Orbit Coupling,"We predict the existence of chiral spin waves collective modes in a
two-dimensional Fermi liquid with the Rashba or Dresselhaus spin-orbit
coupling. Starting from the phenomenological Landau theory, we show that the
long-wavelength dynamics of magnetization is governed by the Klein- Gordon
equations. The standing-wave solutions of these equations describe ""particles""
with effective masses, whose magnitudes and signs depend on the strength of the
electron-electron interaction. The spectrum of the spin-chiral modes for
arbitrary wavelengths is determined from the Dyson equation for the interaction
vertex. We propose to observe spin-chiral modes via microwave absorption of
standing waves confined by an in-plane profile of the spin-orbit splitting.",1209.1647v1
2016-03-30,Low-damping transmission of spin waves through YIG/Pt-based layered structures for spin-orbit-torque applications,"We show that in YIG-Pt bi-layers, which are widely used in experiments on the
spin transfer torque and spin Hall effects, the spin-wave amplitude
significantly decreases in comparison to a single YIG film due to the
excitation of microwave eddy currents in a Pt coat. By introducing a novel
excitation geometry, where the Pt layer faces the ground plane of a microstrip
line structure, we suppressed the excitation of the eddy currents in the Pt
layer and, thus, achieved a large increase in the transmission of the
Damon-Eshbach surface spin wave. At the same time, no visible influence of an
external dc current applied to the Pt layer on the spin-wave amplitude in the
YIG-Pt bi-layer was observed in our experiments with YIG films of micrometer
thickness.",1603.09201v1
2021-08-12,Magnetic interactions and spin excitations in van der Waals ferromagnet VI$_3$,"Using a combination of density functional theory (DFT) and spin-wave theory
methods, we investigate the magnetic interactions and spin excitations in
semiconducting VI$_3$. Exchange parameters of monolayer, bilayer, and bulk
forms are evaluated by mapping the magnetic energies of various spin
configurations, calculated using DFT+$U$, onto the Heisenberg model. The
intralayer couplings remain largely unchanged in three forms of VI$_3$, while
the interlayer couplings show stronger dependence on the dimensionality of the
materials. We calculate the spin-wave spectra within a linear spin-wave theory
and discuss how various exchange parameters affect the magnon bands. The
magnon-magnon interaction is further incorporated, and the Curie temperature is
estimated using a self-consistently renormalized spin-wave theory. To
understand the roles of constituent atoms on magnetocrystalline anisotropy
energy (MAE), we resolve MAE into sublattices and find that a strong negative
V-I inter-sublattice contribution is responsible for the relatively small
easy-axis MAE in VI$_3$.",2108.05528v1
2017-03-22,Quantum spin Hall density wave insulator of correlated fermions,"We present the theory of a new type of topological quantum order which is
driven by the spin-orbit density wave order parameter, and distinguished by
$Z_2$ topological invariant. We show that when two oppositely polarized chiral
bands [resulting from the Rashba-type spin-orbit coupling $\alpha_k$, $k$ is
crystal momentum] are significantly nested by a special wavevector ${\bf
Q}\sim(\pi,0)/(0,\pi)$, it induces a spatially modulated inversion of the
chirality ($\alpha_{k+Q}=\alpha_k^*$) between different sublattices. The
resulting quantum order parameters break translational symmetry, but preserve
time-reversal symmetry. It is inherently associated with a $Z_2$-topological
invariant along each density wave propagation direction. Hence it gives a weak
topological insulator in two dimensions, with even number of spin-polarized
boundary states. This phase is analogous to the quantum spin-Hall state, except
here the time-reversal polarization is spatially modulated, and thus it is
dubbed quantum spin-Hall density wave (QSHDW) state. This order parameter can
be realized or engineered in quantum wires, or quasi-2D systems, by tuning the
spin-orbit couping strength and chemical potential to achieve the special
nesting condition.",1703.07629v1
2021-07-19,Damped Dirac magnon in a metallic kagome antiferromagnet FeSn,"The kagome lattice is a fertile platform to explore topological excitations
with both Fermi-Dirac and Bose-Einstein statistics. While relativistic Dirac
Fermions and flat-bands have been discovered in the electronic structure of
kagome metals, the spin excitations have received less attention. Here we
report inelastic neutron scattering studies of the prototypical kagome magnetic
metal FeSn. The spectra display well-defined spin waves extending up to 120
meV. Above this energy, the spin waves become progressively broadened,
reflecting interactions with the Stoner continuum. Using linear spin wave
theory, we determine an effective spin Hamiltonian that reproduces the measured
dispersion. This analysis indicates that the Dirac magnon at the K-point
remarkably occurs on the brink of a region where well-defined spin waves become
unobservable. Our results emphasize the influential role of itinerant carriers
on the topological spin excitations of metallic kagome magnets.",2107.08915v1
2023-01-12,Towards Magnonic Logic and Neuromorphic Computing: Controlling Spin-Waves by Spin-Polarized Current,"Spin-waves (magnons) are among the prime candidates for building fast yet
energy-efficient platforms for information transport and computing. We here
demonstrate theoretically and in state-of-the-art micromagnetic simulation the
effects that strategically-injected spin-polarized current can have on
controlling magnonic transport. We reveal analytically that the Zhang-Li
spin-transfer-torque induced by applied current is analogous to the
Dzyaloshinskii-Moriya interaction for scattering the magnons in the linear
regime, to then provide a generalized Snell's law that describes the spin-wave
propagation across regions with different current densities. We validate the
latter in numerical simulations of realistic systems, and exemplify how these
findings may help advance the design of spin-wave logic and neuromorphic
computing devices.",2301.04922v1
2023-10-02,Breakdown of Linear Spin-Wave Theory in a Non-Hermitian Quantum Spin Chain,"We present the spin-wave theory of the excitation spectrum and quench
dynamics of the non-Hermitian transverse-field Ising model. The complex
excitation spectrum is obtained for a generic hypercubic lattice using the
linear approximation of the Holstein-Primakoff transformation together with the
complex bosonic Bogolyubov transformation. In the one-dimensional case, our
result compares very well with the exact quasiparticle dispersion relation
obtained via a fermionic representation of the problem, at least in the regime
of large dissipation and transverse field. When applied to the quench dynamics
we show however that the linear spin-wave approximation breaks down and the
bosonic theory is plagued by a divergence at finite times. We understand the
origin of this instability using a single mode approximation. While limited to
short times, we show that this approach allows us to characterize the dynamics
arising from the quench of the dissipative term and the structure of the
Lieb-Robinson light-cone of the propagation quantum correlations. Furthermore,
for the one-dimensional case, the linear spin-wave dynamics shows good
agreement with the exact fermionic solution, both for the local magnetization
and the spin-spin correlations.",2310.00985v1
2005-02-14,1/S-expansion study of spin waves in a two-dimensional Heisenberg antiferromagnet,"We study the effects of quantum fluctuations on excitation spectra in the
two-dimensional Heisenberg antiferromagnet by means of the 1/S expansion. We
calculate the spin-wave dispersion and the transverse dynamical structure
factor up to the second order of 1/S in comparison with inelastic neutron
scattering experiments. The spin-wave energy at momentum $(\pi,0)$ is found to
be about 2% smaller than that at $(\pi/2,\pi/2)$ due to the second-order
correction. In addition, we study the dimensional crossover from two dimensions
to one dimension by weakening exchange couplings in one direction. It is found
that the second-order correction becomes large with approaching the quasi-one
dimensional situation and makes the spin-wave energy approach to the des
Cloizeaux-Pearson boundary for $S=1/2$. The transverse dynamical structure
factor is also calculated up to the second order of 1/S. It is shown that the
intensity of spin-wave peak is strongly reduced while the intensity of
three-spin-wave continuum becomes large and exceeds that of the spin-wave peak
in the quasi-one dimensional situation.",0502318v2
2009-07-31,Magnetic Cellular Nonlinear Network with Spin Wave Bus for Image Processing,"We describe and analyze a cellular nonlinear network based on magnetic
nanostructures for image processing. The network consists of magneto-electric
cells integrated onto a common ferromagnetic film - spin wave bus. The
magneto-electric cell is an artificial two-phase multiferroic structure
comprising piezoelectric and ferromagnetic materials. A bit of information is
assigned to the cell's magnetic polarization, which can be controlled by the
applied voltage. The information exchange among the cells is via the spin waves
propagating in the spin wave bus. Each cell changes its state as a combined
effect of two: the magneto-electric coupling and the interaction with the spin
waves. The distinct feature of the network with spin wave bus is the ability to
control the inter-cell communication by an external global parameter - magnetic
field. The latter makes possible to realize different image processing
functions on the same template without rewiring or reconfiguration. We present
the results of numerical simulations illustrating image filtering, erosion,
dilation, horizontal and vertical line detection, inversion and edge detection
accomplished on one template by the proper choice of the strength and direction
of the external magnetic field. We also present numerical assets on the major
network parameters such as cell density, power dissipation and functional
throughput, and compare them with the parameters projected for other
nano-architectures such as CMOL-CrossNet, Quantum Dot Cellular Automata, and
Quantum Dot Image Processor. Potentially, the utilization of spin waves
phenomena at the nanometer scale may provide a route to low-power consuming and
functional logic circuits for special task data processing.",0907.5453v1
2011-02-15,Tunneling properties of Bogoliubov mode and spin wave modes in supercurrent states of a spin-1 ferromagnetic spinor Bose-Einstein condensate,"We investigate tunneling properties of collective excitations in the
ferromagnetic phase of a spin-1 spinor Bose-Einstein condensate (BEC). In
addition to the Bogoliubov mode, this superfluid phase has two spin
excitations, namely, the gapless transverse spin wave and the quadrupolar mode
with a finite excitation gap. In the mean-field theory at T=0, we examine how
these collective modes tunnel through a barrier potential that couples to the
local density of particles. In the presence of supercurrent with a finite
momentum $q$, while the Bogoliubov mode shows the so-called anomalous tunneling
behavior (which is characterized by perfect transmission) in the low energy
limit, the transverse spin-wave transmits perfectly only when the momentum $k$
of this mode coincides with $\pm q$. At $k=\pm q$, the wave function of this
spin wave has the same form as the condensate wave function in the current
carrying state, so that the mechanism of this perfect transmission is found to
be the same as tunneling of supercurrent. Using this fact, the perfect
transmission of the spin wave is proved for a generic barrier potential. We
show that such perfect transmission does not occur in the quadrupolar mode.
Further, we consider the effects of potentials breaking U(1) and spin rotation
symmetries on the transmission properties of excitations. Our results would be
useful for understanding excitation properties of spinor BECs, as well as the
anomalous tunneling phenomenon in Bose superfluids.",1102.3113v1
2019-02-11,Spin-wave phase inverter upon a single nanodefect,"Local modification of magnetic properties of nanoelements is a key to design
future-generation magnonic devices, in which information is carried and
processed via spin waves. One of the biggest challenges here is to fabricate
simple and miniature phase-controlling elements with broad tunability. Here, we
successfully realize such spin-wave phase shifter upon a single nanogroove
milled by focused ion beam in a Co-Fe microsized magnonic waveguide. By varying
the groove depth and the in-plane bias magnetic field we continuously tune the
spin-wave phase and experimentally evidence a complete phase inversion. The
microscopic mechanism of the phase shift is based on the combined action of the
nanogroove as a geometrical defect and the lower spin-wave group velocity in
the waveguide under the groove where the magnetization is reduced due to the
incorporation of Ga ions during the ion-beam milling. The proposed phase
shifter can easily be on-chip integrated with spin-wave logic gates and other
magnonic devices. Our findings are crucial for designing nano-magnonic circuits
and for the development of spin-wave nano-optics.",1902.03758v1
2021-04-09,Measuring the dispersion relations of spin wave bands using time-of-flight spectroscopy,"We develop a generic all-inductive procedure to measure the band structure of
spin waves in a magnetic thin stripe. In contrast to existing techniques, our
method works even if several spin wave branches coexist in the investigated
frequency interval, provided that the branches possess sufficiently different
group velocities. We first measure the microwave scattering matrix of a network
composed of distant antennas inductively coupled to the spin wave bath of the
magnetic film. After a mathematical transformation to the time-domain to get
the transmission impulse response, the different spin wave branches are viewed
as wavepackets that reach successively the receiving antenna after different
travel times. In analogy with time-of flight spectroscopy, the wavepackets are
then separated by time-gating. The time-gated responses are used to recalculate
the contribution of each spin wave branch to the frequency domain scattering
matrix. The dispersion relation of each branch stems from the absolute phase of
the time-gated transmission parameter. The spin wave wavevector can be
determined unambiguously if the results for several propagation distances are
combined, so as to get the dispersion relations.",2104.04262v2
2021-04-16,Implementing a magnonic time-delay reservoir computer model,"Recently we demonstrated experimentally that microwave oscillators based on
the time delay feedback provided by traveling spin waves could operate as
reservoir computers. In the present paper, we extend this concept by adding the
feature of time multiplexing made available by the large propagation
times/distances of traveling spin waves. The system utilizes the nonlinear
behavior of propagating magnetostatic surface spin waves in a yttrium-iron
garnet thin film and the time delay inherent in the active ring configuration
to process time dependent data streams. Higher reservoir dimensionality is
obtained through the time-multiplexing method, emulating ""virtual"" neurons as
temporally separated spin-wave pulses circulating in the active ring below the
auto-oscillation threshold. To demonstrate the efficacy of the concept, the
active ring reservoir computer is evaluated on the short-term memory and parity
check benchmark tasks, and the physical system parameters are tuned to optimize
performance. By incorporating a reference line to mix the input signal directly
onto the active ring output, both the amplitude and phase nonlinearity of the
spin waves can be exploited, resulting in significant improvement on the
nonlinear parity check task. We also find that the fading memory capacity of
the system can be easily tuned by controlling the active ring gain. Finally, we
show that the addition of a second spin-wave delay line configured to transmit
backward volume spin waves can partly compensate dispersive pulse broadening
and enhance the fading memory capacity of the active ring.",2104.07879v1
2017-03-20,Spin-Wave Dynamics in the Presence of Magnetic Vortices,"This chapter describes spin-wave excitations in nanosized dots and rings in
the presence of the vortex state. The special attention is paid to the
manifestation of the competition between exchange and dipolar interactions in
the spin-wave spectrum as well as the correlation between the spectrum and the
stability of the vortex. The calculation method uses the dynamic matrix for an
all-discrete system, the numerical diagonalization of which yields the spectrum
of frequencies and spin-wave profiles of normal modes of the dot. We study
in-plane vortices of two types: a circular magnetization in circular dots and
rings and the Landau state in square rings. We examine the influence of the
dipolar-exchange competition and the geometry of the dot on the stability of
the vortex and on the spectrum of spin waves. We show that the lowest-frequency
mode profile proves to be indicative of the dipolar-to-exchange interaction
ratio and the vortex stability is closely related to the spin-wave profile of
the soft mode. The negative dispersion relation is also shown. Our results
obtained for in-plane vortices are in qualitative agreement with results for
core-vortices obtained from experiments, micromagnetic simulations, and
analytical calculations.",1703.06668v1
2019-01-02,Skyrmion Tubes as Magnonic Waveguides,"Various latest experiments have proven the theoretical prediction that domain
walls in planar magnetic structures can channel spin waves as outstanding
magnonic waveguides, establishing a superb platform for building magnonic
devices. Recently, three-dimensional nanomagnetism has been boosted up and
become a significant branch of magnetism, because three-dimensional magnetic
structures expose a lot of emerging physics hidden behind planar ones and will
inevitably provide broader room for device engineering. Skyrmions and
antiSkyrmions, as natural three-dimensional magnetic configurations, are not
considered yet in the context of spin-wave channeling and steering. Here, we
show that skyrmion tubes can act as nonplanar magnonic waveguides if excited
suitably. An isolated skyrmion tube in a magnetic nanoprism induces spatially
separate internal and edge channels of spin waves; the internal channel has a
narrower energy gap, compared to the edge channel, and accordingly can transmit
signals at lower frequencies. Additionally, we verify that those spin-wave
beams along magnetic nanoprism are restricted to the regions of potential
wells. Transmission of spin-wave signals in such waveguides results from the
coherent propagation of locally driven eigenmodes of skyrmions, i.e., the
breathing and rotational modes. Finally, we find that spin waves along the
internal channels are less susceptible to magnetic field than those along the
edge channels. Our work will open a new arena for spin-wave manipulation and
help bridge skyrmionics and magnonics.",1901.00253v1
2020-06-28,Hydrodynamics of quantum corrections to the Coulomb interaction via the third rank tensor evolution equation: Application to the Langmuir waves and the spin-electron-acoustic waves,"If we study the quantum effects in plasmas in terms of traditional
hydrodynamics via the continuity and Euler equations we find the quantum Bohm
potential and the force of spin-spin interaction. However, if we extend the set
hydrodynamic equations beyond the 13-moments approximation, and include the
third rank tensor evolution equation along with the pressure evolution
equation, we obtain the quantum corrections to the Coulomb interaction. It is
found in contrast with the fact that hydrodynamic equations for the higher rank
tensors do not contain interaction in the classic plasmas studied in the
selfconsistent (meanfield) approximation. Therefore, we present the quantum
hydrodynamic model, where the quantum effects are studied beyond the quantum
Bohm potential. Developed model is considered in two regimes: all electrons in
plasmas are considered as the single fluid, and the separate spin evolution
regime, where electrons with different spin projections are considered as two
different fluids. To illustrate the fundamental meaning of found quantum
effects we demonstrate their contribution in the spectrum of the Langmuir waves
and the spin-electron-acoustic waves. It is worth to mention that the
application of the pressure evolution equation ensures that the contribution of
pressure in the Langmuir wave spectrum is proportional to $(3/5)v_{Fe}^{2}$,
unlike $(1/3)v_{Fe}^{2}$ appearing from hydrodynamics based on the continuity
and Euler equations, where $v_{Fe}$ is the Fermi velocity. Same correction
corresponds on other plasmas phenomena like the speed of sound for
spin-electron-acoustic waves. Moreover, it is found that novel quantum effects
provide the novel wave solutions.",2006.15656v1
2023-06-27,"Three-dimensional spin-wave dynamics, localization and interference in a synthetic antiferromagnet","Spin waves are collective perturbations in the orientation of the magnetic
moments in magnetically ordered materials. Their rich phenomenology is
intrinsically three-dimensional; however, the three-dimensional imaging of spin
waves has so far not been possible. Here, we image the three-dimensional
dynamics of spin waves excited in a synthetic antiferromagnet, with nanoscale
spatial resolution and sub-ns temporal resolution, using time-resolved magnetic
laminography. In this way, we map the distribution of the spin-wave modes
throughout the volume of the structure, revealing unexpected depth-dependent
profiles originating from the interlayer dipolar interaction. We experimentally
demonstrate the existence of complex three-dimensional interference patterns
and analyze them via micromagnetic modelling. We find that these patterns are
generated by the superposition of spin waves with non-uniform amplitude
profiles, and that their features can be controlled by tuning the composition
and structure of the magnetic system. Our results open unforeseen possibilities
for the study and manipulation of complex spin-wave modes within nanostructures
and magnonic devices.",2306.15404v2
1997-11-25,Resonant tunneling of electromagnetic waves through polariton gaps,"We consider resonant tunneling of electromagnetic waves through an optical
barrier formed by dielectric layers with the frequency dispersion of their
dielectric permiability. The frequency region between lower and upper polariton
branches in these materials presents a stop band for electromagnetic waves. We
show that resonance tunneling through this kind of barriers is qualitatevely
different from tunneling through other kind of optical barriers as well as from
quantum mechanic tunneling through a rectangular barrier. We find that the
width of the resonance maxima of the transmission coeffcient tends to zero as
frequency approach the lower boundary of the stop band in a very sharp
non-analytical way. Resonance transmission peaks give rise to new photonic
bands inside the stop band if one considers periodical array of the layers.",9711268v2
2003-07-08,Resonant acousto-optics of microcavity polaritons,"We propose and analyze theoretically a resonant acousto-optic Stark effect
for microcavity (MC) polaritons parametrically driven by a surface acoustic
wave. For GaAs-based microcavities our scheme ``acoustic pumping - optical
probing'' deals with surface acoustic waves of frequency $\nu_{\rm SAW} \simeq
0.5 - 3$ GHz and intensity $I_{\rm SAW} \simeq 0.1 - 10$ mW/mm. The
acoustically-induced stop gaps in the MC polariton spectrum drastically change
the optical response of MC polaritons. Because an acoustically pumped intrinsic
semiconductor microcavity remains in its ground electronic state, no many-body
effects screen and weaken the resonant acousto-optic Stark effect. In the
meantime, this allows us to work out an exactly-solvable model for resonant
acousto-optics of MC polaritons which deals with giant acousto-optical
nonlinearities. Finally, we discuss possible applications of the proposed
resonant acoustic Stark effect for optical modulation and switching and
describe an acousto-optic device based on a (GaAs) microcavity driven by a
surface acoustic wave.",0307179v1
2003-09-26,"Near-Resonant, Steady Mode Interaction: Periodic, Quasi-Periodic and Localized Patterns","Motivated by the rich variety of complex periodic and quasi-periodic patterns
found in systems such as two-frequency forced Faraday waves, we study the
interaction of two spatially periodic modes that are nearly resonant. Within
the framework of two coupled one-dimensional Ginzburg-Landau equations we
investigate analytically the stability of the periodic solutions to general
perturbations, including perturbations that do not respect the periodicity of
the pattern, and which may lead to quasi-periodic solutions. We study the
impact of the deviation from exact resonance on the destabilizing modes and on
the final states. In regimes in which the mode interaction leads to traveling
waves our numerical simulations reveal localized waves in which the wavenumbers
are resonant and which drift through a steady background pattern that has an
off-resonant wavenumber ratio.",0309070v2
2011-12-12,Dispersion in media containing resonant inclusions: where does it come from?,"We study the propagation of waves in a quasi 1D homogeneous host medium
filled with various resonators. We first prove that a far field coupling
between the elements explains its dispersive nature. This coupling is
interpreted as a Fano interference between the incoming wave and the waves
re-radiated by each resonator, which experience a phase shift at resonance. We
propose a simple formalism that gives the complete dispersion relation of the
medium in terms of the far field response of a single resonator. We prove that
our approach applies to and unifies various domains such as metamaterials,
hybridization band gap materials and designer's plasmons. Finally we show that
those media, spatially random or organized on a scale larger than the
wavelength, also present very interesting properties, which broadens the range
of man made exotic materials.",1112.2524v1
2015-03-05,Resonance broadening due to particle scattering and mode-coupling in the quasi-linear relaxation of electron beams,"Of particular interest for radio and hard X-ray diagnostics of accelerated
electrons during solar flares is the understanding of the basic non-linear
mechanisms regulating the relaxation of electron beams propagating in turbulent
plasmas. In this work, it is shown that in addition to scattering of beam
electrons, scattering of the beam-generated Langmuir waves via for instance
mode-coupling, can also result in broadening of the wave-particle resonance. We
obtain a resonance-broadened version of weak-turbulence theory with
mode-coupling to ion-sound modes. Resonance broadening is presented here as a
unified framework which can quantitatively account for the reduction and
possible suppression of the beam instability due to background scattering of
the beam electrons themselves or due to scattering of the beam-generated
Langmuir waves in fluctuating plasmas. Resonance broadening being essentially
equivalent to smoothing of the electron phase-space distribution, it is used to
construct an intuitive physical picture for the stability of inverted
populations of fast electrons that are commonly observed \emph{in-situ} to
propagate in the solar-wind.",1503.01710v1
2017-08-14,Giant THz surface plasmon polariton induced by high-index dielectric metasurface,"We use computational approaches to explore the role of a
high-refractive-index dielectric TiO2 grating with deep subwavelength thickness
on InSb as a tunable coupler for THz surface plasmons. We find a series of
resonances as the grating couples a normally-incident THz wave to standing
surface plasmon waves on both thin and thick InSb layers. In a marked contrast
with previously-explored metallic gratings, we observe the emergence of a much
stronger additional resonance. The mechanism of this giant plasmonic resonance
is well interpreted by the dispersion of surface plasmon excited in the
air\TiO2\InSb trilayer system. We demonstrate that both the frequency and the
intensity of the giant resonance can be tuned by varying dielectric grating
parameters, providing more flexible tunability than metallic gratings. The
phase and amplitude of the normally-incident THz wave are spatially modulated
by the dielectric grating to optimize the surface plasmon excitation. The giant
surface plasmon resonance gives rise to strong enhancement of the electric
field above the grating structure, which can be useful in sensing and
spectroscopy applications.",1709.08812v1
2017-11-17,Resonance frequency broadening of wave-particle interaction in tokamaks due to Alfvénic eigenmode,"We use a guiding center code ORBIT to study the broadening of resonances and
the parametric dependence of the resonance frequency broadening width
$\Delta\Omega$ on the nonlinear particle trapping frequency $\omega_b$ of
wave-particle interaction with specific examples using realistic equilibrium
DIII-D shot 159243 (Collins et al. 2016 Phys. Rev. Lett. 116 095001). When the
mode amplitude is small, the pendulum approximation for energetic particle
dynamics near the resonance is found to be applicable and the ratio of the
resonance frequency width to the deeply trapped bounce frequency
$\Delta\Omega/\omega_b$ equals 4, as predicted by theory. This factor 4 is
demonstrated for the first time in realistic instability conditions. It is
found that as the mode amplitude increases, the coefficient
$a=\Delta\Omega/\omega_b$ becomes increasingly smaller because of the breaking
down of the nonlinear pendulum approximation for the wave-particle interaction.",1711.06574v1
2017-12-02,Phonon-interference resonance effects in nanoparticles embedded in a matrix,"We report an unambiguous phonon resonance effect originating from germanium
nanoparticles embedded in silicon matrix. Our approach features the combination
of phonon wave-packet method with atomistic dynamics and finite element method
rooted in continuum theory. We find that multimodal phonon resonance, caused by
destructive interference of coherent lattice waves propagating through and
around the nanoparticle, gives rise to sharp and significant transmittance
dips, blocking the lower-end frequency range of phonon transport that is hardly
diminished by other nanostructures. The resonance is sensitive to the phonon
coherent length, where the finiteness of the wave packet width weakens the
transmittance dip even when coherent length is longer than the particle
diameter. Further strengthening of transmittance dips are possible by arraying
multiple nanoparticles that gives rise to the collective vibrational mode.
Finally, it is demonstrated that these resonance effects can significantly
reduce thermal conductance in the lower-end frequency range.",1712.00564v1
2018-01-19,Three-body recombination near a narrow Feshbach resonance in $^6$Li,"We experimentally measure, and theoretically analyze the three-atom
recombination rate, $L_3$, around a narrow $s$ wave magnetic Feshbach resonance
of $^6$Li-$^6$Li at 543.3 Gauss. By examining both the magnetic field
dependence and especially the temperature dependence of $L_3$ over a wide range
of temperatures from a few $\mu$K to above 200 $\mu$K, we show that three-atom
recombination through a narrow resonance follows a universal behavior
determined by the long-range van der Waals potential, and can be described by a
set of rate equations in which three-body recombination proceeds via successive
pairwise interactions. We expect the underlying physical picture to be
applicable not only to narrow $s$ wave resonances, but also to resonances in
nonzero partial waves, and not only at ultracold temperatures, but also at much
higher temperatures.",1801.06489v1
2018-09-23,Quantum-Mechanical interpretation of Riemann zeta function zeros,"We demonstrate that the Riemann zeta function zeros define the position and
the widths of the resonances of the quantised Artin dynamical system. The Artin
dynamical system is defined on the fundamental region of the modular group on
the Lobachevsky plane. It has a finite volume and an infinite extension in the
vertical direction that correspond to a cusp. In classical regime the geodesic
flow in the fundamental region represents one of the most chaotic dynamical
systems, has mixing of all orders, Lebesgue spectrum and non-zero Kolmogorov
entropy. In quantum-mechanical regime the system can be associated with the
narrow infinitely long waveguide stretched out to infinity along the vertical
axis and a cavity resonator attached to it at the bottom. That suggests a
physical interpretation of the Maass automorphic wave function in the form of
an incoming plane wave of a given energy entering the resonator, bouncing
inside the resonator and scattering to infinity. As the energy of the incoming
wave comes close to the eigenmodes of the cavity a pronounced resonance
behaviour shows up in the scattering amplitude.",1809.09491v1
2019-11-15,Hybrid Magnetoacoustic Metamaterials for Ultrasound Control,"We propose a class of metamaterials in which propagation of acoustic waves is
controlled magnetically through magnetoelastic coupling. The metamaterials are
formed by a periodic array of thin magnetic layers ('resonators') embedded in a
non-magnetic matrix. Acoustic waves carrying energy through the structure
hybridize with the magnetic modes of the resonators ('Fano resonance'). This
leads to a rich set of effects, enhanced by Bragg scattering and being most
pronounced when the magnetic resonance frequency is close to or lies within
acoustic band gaps. The acoustic reflection from the structure exhibits
magnetically induced transparency and Borrmann effect. Our analysis shows that
the combined effect of the Bragg scattering and Fano resonance may overcome the
magnetic damping ubiquitous in realistic systems. This paves a route towards
application of such structures in wave computing and signal processing",1911.06774v1
2017-10-12,Scattering of flexural waves from an $N$-beam resonator in a thin plate,"The impedance matrix method is applied to study the scattering of flexural
waves propagating in an infinite thin plate containing an $N$-beam resonator.
The resonator consists of a circular hole containing a smaller plate connected
to the background plate by a number $N$ of rectangular beams. After
representing the boundary conditions in a modal multipole expansion form, a
compact expression is obtained for the T-matrix, which relates the incident and
the scattered transverse (out-of-plane) waves. The analysis of the scattering
cross-section reveals interesting scattering features, like resonances and
anisotropy, associated with this type of resonators. Numerical experiments
performed within the framework of the finite element method support the
accuracy of the model here developed.",1710.04610v1
2019-07-08,Hyperon I: Partial wave amplitudes for $K^-p$ scattering,"Early data on $K^-$ induced reactions off protons are collected and used in a
coupled-channel partial wave analysis (PWA). Data which had been published in
the form of Legendre coefficients are included in the PWA. In a {\it primary}
fit using 3* and 4* resonances only, we observe some significant discrepancies
with the data. In a systematic search for new $\Lambda$ and $\Sigma$ hyperon
resonances, additional candidates are found. The significance of the known and
of the additional resonances is evaluated. Seventeen resonances listed with 1*
or 2* and one resonance listed with 3* in the Review of Particle Properties
cannot be confirmed, five new hyperons are suggested. The partial-wave
amplitudes deduced in this analysis are compared to those from other analyses.",1907.03645v1
2019-05-26,Piezo-optomechanical coupling of a 3D microwave resonator to a bulk acoustic wave crystalline resonator,"We report the observation of coupling between a 3D microwave cavity mode and
a bulk mechanical resonator mediated by piezoelectric and radiation pressure
effects. The system is composed of a quartz bulk acoustic wave resonator placed
inside a microwave re-entrant cavity, which is designed to act as both the
electrodes for piezoelectric actuation as well as a 3D resonator. The cavity
electromagnetic mode is modulated by a 5 MHz bulk acoustic wave shear mode,
which is modeled and experimentally verified using the input-output formalism.
Through finite element method simulations, we calculate the various
contributions to the electromechanical coupling and discuss the potential of
the system to reach high cooperativities as well as suitable applications.",1907.10753v2
2021-03-10,Modulated rotating waves and triadic resonances in spherical fluid systems: The case of magnetized spherical Couette flow,"The existence of triadic resonances in the magnetized spherical Couette
system (MSC) is related to the development of modulated rotating waves, which
are quasiperiodic flows understood in terms of bifurcation theory in systems
with symmetry. In contrast to previous studies in spherical geometry the
resonant modes are not inertial waves but related with the radial jet
instability which is strongly equatorially antisymmetric. We propose a general
framework in which triadic resonances are generated through successive Hopf
bifurcations from the base state. The study relies on an accurate frequency
analysis of different modes of the flow, for solutions belonging to two
different bifurcation scenarios. The azimuthal and latitudinal nonlinear
coupling among the resonant modes is analysed and interpreted using spherical
harmonics and the results are compared with previous studies in spherical
geometry.",2103.05924v1
2021-03-12,Effects of external flow on resonant absorption of coronal loop kink oscillations driven by an external fast wave: Selective excitation problem,"Resonant absorption is considered as a crucial mechanism for the damping of
the coronal loop oscillations and plasma heating. We study resonant absorption
of the coronal loop kink oscillations excited by such external drivers as
flares on the assumption that there is an intermediate shear flow region
surrounding the loop. We find that for long coronal loops resonant absorption
can be highly enhanced or reduced depending sensitively on the magnitude and
direction of the flow and the spatial extent of the flow region when the
transitional layer is thin. For short coronal loops, high flow speed and thick
transitional layer are needed to have a substantial resonant absorption. We
provide a potential picture to explain the results where the external
Alfv\'{e}n speed and phase speed of the wave are important parameters. These
results imply that the transport of the external wave energy into the loop is
significantly changed by the shear flow region, which may cause the selective
excitation of the coronal loop oscillations.",2103.07063v2
2022-07-18,Non-local scattering control in coupled resonator networks,"We demonstrate scattering control of Gaussian-like wave packets propagating
with constant envelope velocity and invariant waist through coupled resonator
optical waveguides (CROW) via an external resonator coupled to multiple sites
of the CROW. We calculate the analytical reflectance and transmittance using
standard scattering methods from waveguide quantum electrodynamics and show it
is possible to approximate them for an external resonator detuned to the CROW.
Our analytical and approximate results are in good agreement with numerical
simulations. We engineer various configurations using an external resonator
coupled to two sites of a CROW to show light trapping with effective
exponential decay between the coupling sites, wave packet splitting into two
pairs of identical Gaussian-like wave packets, and a non-local Mach-Zehnder
interferometer.",2207.08932v1
2023-10-18,Physics-informed Neural Network for Acoustic Resonance Analysis in a One-Dimensional Acoustic Tube,"This study devised a physics-informed neural network (PINN) framework to
solve the wave equation for acoustic resonance analysis. The proposed
analytical model, ResoNet, minimizes the loss function for periodic solutions
and conventional PINN loss functions, thereby effectively using the function
approximation capability of neural networks while performing resonance
analysis. Additionally, it can be easily applied to inverse problems. The
resonance in a one-dimensional acoustic tube, and the effectiveness of the
proposed method was validated through the forward and inverse analyses of the
wave equation with energy-loss terms. In the forward analysis, the
applicability of PINN to the resonance problem was evaluated via comparison
with the finite-difference method. The inverse analysis, which included
identifying the energy loss term in the wave equation and design optimization
of the acoustic tube, was performed with good accuracy.",2310.11804v3
2001-06-05,Magnetic Resonance of Spin Clusters and Triplet Excitations in a Spin-Peierls Magnet with Impurities,"The magnetic resonance spectrum of spin clusters formed in spin-Peierls
magnets in the vicinity of impurity ions was investigated. The observed
temperature dependences of the effective g-factor and the linewidth of the
electron spin resonance (ESR) in crystals of Cu(1-x)Ni(x)GeO(3) are described
in the model of the exchange narrowing of the two-component spectrum with one
component ascribed to spin clusters and exhibiting an anomalous value of the
$g$-factor and the other related to triplet excitations. An estimation of the
size of the suppressed dimerization region around the impurity ion is obtained
(this region includes about 30 copper ions). The dependence of the effective
g-factor and the ESR linewidth on the impurity concentration at low
temperatures indicates the interaction of clusters.",0106069v1
2004-04-16,Resonant photon absorption in the low spin molecule V15,"We report the first study of the micro-SQUID response of a molecular system
to electromagnetic radiation. The advantages of our micro-SQUID technique in
respect to pulsed electron paramagnetic resonance (EPR) techniques consist in
the possibility to perform time-resolved experiments (below 1 ns) on
submicrometer sizes samples (about 1000 spins) at low temperature (below 100
mK).
  Resonant photon absorption in the GHz range was observed via low temperature
micro-SQUID magnetization measurements of the spin ground state S = 1/2 of the
molecular complex V15. The line-width essentially results from intra-molecular
hyperfine interaction. The results point out that observing Rabi oscillations
in molecular nanomagnets requires well isolated low spin systems and high
radiation power. Our first results open the way for time-resolved observations
of quantum superposition of spin-up and spin-down states in SMMs.",0404410v1
2004-06-08,Spin injection and detection by resonant tunneling structure,"A theory of spin-dependent electron transmission through resonant tunneling
diode (RTD) grown of non-centrosymmetrical semiconductor compounds has been
presented. It has been shown that RTD can be employed for injection and
detection of spin-polarized carriers: (i) electric current flow in the
interface plane leads to spin polarization of the transmitted carriers, (ii)
transmission of the spin-polarized carriers through the RTD is accompanied by
generation of an in-plane electric current. The microscopic origin of the
effects is the spin-orbit coupling-induced splitting of the resonant level.",0406191v1
2003-07-04,Characterizing the spin state of an atomic ensemble using the magneto-optical resonance method,"Quantum information protocols utilizing atomic ensembles require preparation
of a coherent spin state (CSS) of the ensemble as an important starting point.
We investigate the magneto-optical resonance method for characterizing a spin
state of cesium atoms in a paraffin coated vapor cell. Atoms in a constant
magnetic field are subject to an off-resonant laser beam and an RF magnetic
field. The spectrum of the Zeeman sub-levels, in particular the weak quadratic
Zeeman effect, enables us to measure the spin orientation, the number of atoms,
and the transverse spin coherence time. Notably the use of 894nm pumping light
on the D1-line, ensuring the state F=4, m_F=4 to be a dark state, helps us to
achieve spin orientation of better than 98%. Hence we can establish a CSS with
high accuracy which is critical for the analysis of the entangled states of
atoms.",0307028v2
2003-07-07,Baseband Detection of Bistatic Electron Spin Signals in Magnetic Resonance Force Microscopy (MRFM),"In single spin Magnetic Resonance Force Microscopy (MRFM), the objective is
to detect the presence of an electron (or nuclear) spin in a sample volume by
measuring spin-induced attonewton forces using a micromachined cantilever. In
the OSCAR method of single spin MRFM, the spins are manipulated by an external
rf field to produce small periodic deviations in the resonant frequency of the
cantilever. These deviations can be detected by frequency demodulation followed
by conventional amplitude or energy detection. In this paper, we present an
alternative to these detection methods, based on optimal detection theory and
Gibbs sampling. On the basis of simulations, we show that our detector
outperforms the conventional amplitude and energy detectors for realistic MRFM
operating conditions. For example, to achieve a 10% false alarm rate and an 80%
correct detection rate our detector has an 8 dB SNR advantage as compared with
the conventional amplitude or energy detectors. Furthermore, at these detection
rates it comes within 4 dB of the omniscient matched-filter lower bound.",0307042v2
2008-10-09,Electron Spin Resonance across the Charge-ordering Transition in YBaMn2O6,"We investigated the metal-ordered manganite system YBaMn2O6 using electron
spin resonance (ESR) in the paramagnetic regime across the charge-ordering and
structural phase transition at T_CO = 480 K and T_t = 520 K, respectively. All
ESR parameters exhibit jump-like changes at T_t while the charge-ordering at
T_CO manifests itself only as a weak and broad anomaly. Above T_t the ESR spin
susceptibility is reduced with respect to the dc-susceptibility, indicating
that only the t_2g-core spins of Mn ions contribute to the resonance
absorption. The contribution of the e_g-spins is suppressed by the time scale
of the polaronic hopping process of the e_g-electrons. The linewidth in this
regime is reminiscent of a Korringa-type relaxation behavior. In this picture
the ESR properties below T_t are dominated by the slowing down of the polaronic
hopping process. The charge fluctuations persist down to the temperature T* ~
410 K, below which the system can be described as a charge-ordered assembly of
Mn$^{3+}$ and Mn$^{4+}$ spins.",0810.1641v1
2011-03-16,Electron spin synchronization induced by optical nuclear magnetic resonance feedback,"We predict a new physical mechanism explaining the electron spin precession
frequency focusing effect observed recently in singly charged quantum dots
exposed to a periodic train of resonant circularly polarized short optical
pulses [A. Greilich et al, Science 317, 1896 (2007), Ref. 1]. We show that
electron spin precession in an external magnetic field and a field of nuclei
creates a Knight field oscillating at the frequency of nuclear spin resonance.
This field drives the projection of the nuclear spin onto magnetic field to the
value that makes the electron spin precession frequency a multiple of the train
cyclic repetition frequency, which is the condition at which the Knight field
vanishes.",1103.3249v2
2012-03-30,Network analyzer measurements of spin transfer torques in magnetic tunnel junctions,"We demonstrate a simple network-analyzer technique to make quantitative
measurements of the bias dependence of spin torque in a magnetic tunnel
junction. We apply a microwave current to exert an oscillating spin torque near
the ferromagnetic resonance frequency of the tunnel junction's free layer. This
produces an oscillating resistance that, together with an applied direct
current, generates a microwave signal that we measure with the network
analyzer. An analysis of the resonant response yields the strength and
direction of the spin torque at non-zero bias. We compare to measurements of
the spin torque vector by time-domain spin-torque ferromagnetic resonance.",1204.0038v2
2012-05-25,Electron spin resonance detected by a superconducting qubit,"A new method for detecting the magnetic resonance of electronic spins at low
temperature is demonstrated. It consists in measuring the signal emitted by the
spins with a superconducting qubit that acts as a single-microwave-photon
detector, resulting in an enhanced sensitivity. We implement this new type of
electron-spin resonance spectroscopy using a hybrid quantum circuit in which a
transmon qubit is coupled to a spin ensemble consisting of NV centers in
diamond. With this setup we measure the NV center absorption spectrum at 30mK
at an excitation level of \thicksim15\,\mu_{B} out of an ensemble of 10^{11}
spins.",1205.5659v1
2012-07-13,Resolving Spin-Orbit and Hyperfine Mediated Electric Dipole Spin Resonance in a Quantum Dot,"We investigate the electric manipulation of a single electron spin in a
single gate-defined quantum dot. We observe that so-far neglected differences
between the hyperfine and spin-orbit mediated electric dipole spin resonance
conditions have important consequences at high magnetic fields. In experiments
using adiabatic rapid passage to invert the electron spin, we observe an
unusually wide and asymmetric response as a function of magnetic field.
Simulations support the interpretation of the lineshape in terms of four
different resonance conditions. These findings may lead to isotope-selective
control of dynamic nuclear polarization in quantum dots.",1207.3331v2
2013-03-01,Spontaneous and resonant lifting of the spin blockade in nanowire quantum dots,"A complete numerical description of the charge and spin dynamics of a
two-electron system confined in narrow nanowire quantum dots under oscillating
electric field is presented in the context of recent electric dipole spin
resonance experiments. We find that the spin-orbit coupling results in lifting
the spin blockade by phonon mediated relaxation provided that the initially
occupied state is close in energy to the ground state. This leads to
suppression of the blockade from the triplet state with spins polarized
parallel to the external magnetic field B. At higher B, after singlet-triplet
ground-state transition a new channel for lifting the Pauli blockade opens
which results in an appearance of additional resonance lines. The calculated
signatures of this transition are consistent with recent experimental results
[S. M. Frolov et al., Phys. Rev. Lett. 109, 236805 (2012)].",1303.0211v2
2013-03-12,Optical signals of spin switching using the optical Stark effect in a Mn doped quantum dot,"The optically induced spin dynamics of a single Mn atom embedded into a
single semiconductor quantum dot can be strongly influenced by using the
optical Stark effect. The exchange interaction gives rise to simultaneous spin
flips between the quantum dot electron and Mn. In the time domain these flips
correspond to exchange induced Rabi oscillations, which are typically
off-resonant. By applying a detuned laser pulse, the states involved in the
flipping can be brought into resonance by means of the optical Stark effect
increasing the amplitude of the Rabi oscillations to one. In this paper we
study theoretically how this spin dynamics can be monitored in time-resolved
spectroscopy. In the spectrum the exchange interaction leads to a splitting of
the exciton line into six lines, each corresponding to one of the six Mn spin
states. The dynamical behavior of the Mn spin is reflected by the strength of
the individual lines as a function of time. When an off-resonant optical pulse
is applied the spectral positions of the lines shift, but still the flipping
dynamics is visible.",1303.2909v1
2013-04-17,Detecting and polarizing nuclear spins with double resonance on a single electron spin,"We report the detection and polarization of nuclear spins in diamond at room
temperature by using a single nitrogen-vacancy (NV) center. We use
Hartmann-Hahn double resonance to coherently enhance the signal from a single
nuclear spin while decoupling from the noisy spin-bath, which otherwise limits
the detection sensitivity. As a proof-of-principle we: (I) observe coherent
oscillations between the NV center and a weakly coupled nuclear spin, (II)
demonstrate nuclear bath cooling which prolongs the coherence time of the NV
sensor by more than a factor of five. Our results provide a route to nanometer
scale magnetic resonance imaging, and novel quantum information processing
protocols.",1304.4709v2
2013-11-20,Spin bath maser in a cryogenically cooled sapphire whispering gallery mode resonator,"We report the observation of a mechanism of maser generation in an ensemble
of inter-coupled, inhomogeneously broadened two-level systems, enhanced by high
quality factor electromagnetic cavity modes. In this previously unobserved form
of population inversion, an inseparable quantum system leads to cavity-enhanced
stimulated emission arising from interactions within an ensemble of two-level
systems, as opposed to a traditional ensemble of noninteracting identical three
level systems. The effect is observed in a cryogenically cooled whispering
gallery mode sapphire resonator containing dilute Fe$^{3+}$ impurity ions.
These ions exhibit strong spin-lattice interaction, leading to both electron
spin resonance broadening and phonon mediated spin-spin coupling. The maser
effect is due to a $\left|1/2\right\rangle \rightarrow \left|3/2\right\rangle$
energy transition in electron spin angular momentum observed at zero external
magnetic field. Both continuous and oscillating regimes are observed with
corresponding thresholds both in detuning frequency and incident power.",1311.4961v2
2013-12-03,Local magnetism and spin correlations in the geometrically frustrated cluster magnet LiZn$_2$Mo$_3$O$_8$,"LiZn$_2$Mo$_3$O$_8$ has been proposed to contain $S~=~1/2$ Mo$_3$O$_{13}$
magnetic clusters arranged on a triangular lattice with antiferromagnetic
nearest-neighbor interactions. Here, microwave and terahertz electron spin
resonance (ESR), $^7$Li nuclear magnetic resonance (NMR), and muon spin
rotation ($\mu \textrm{SR}$) spectroscopies are used to characterize the local
magnetic properties of LiZn$_2$Mo$_3$O$_8$. These results show the magnetism in
LiZn$_2$Mo$_3$O$_8$ arises from a single isotropic $S~=~1/2$ electron per
cluster and that there is no static long-range magnetic ordering down to
$T~=~0.07\,\textrm{K}$. Further, there is evidence of gapless spin excitations
with spin fluctuations slowing down as the temperature is lowered. These data
indicate strong spin correlations which, together with previous data, suggest a
low-temperature resonating valence-bond state in LiZn$_2$Mo$_3$O$_8$.",1312.0955v1
2014-03-04,Off-Resonant Manipulation of Spins in Diamond via Precessing Magnetization of a Proximal Ferromagnet,"We report the manipulation of nitrogen vacancy (NV) spins in diamond when
nearby ferrimagnetic insulator, yttrium iron garnet, is driven into precession.
The change in NV spin polarization, as measured by changes in
photoluminescence, is comparable in magnitude to that from conventional
optically detected magnetic resonance, but relies on a distinct mechanism as it
occurs at a microwave frequency far removed from the magnetic resonance
frequency of the NV spin. This observation presents a new approach to
transferring ferromagnetic spin information into a paramagnet and then
transducing the response into a robust optical signal. It also opens new
avenues for studying ferromagnetism and spin transport at the nanoscale.",1403.0656v1
2014-04-05,Single spin stochastic optical reconstruction microscopy,"We experimentally demonstrate precision addressing of single quantum emitters
by combined optical microscopy and spin resonance techniques. To this end we
utilize nitrogen-vacancy (NV) color centers in diamond confined within a few
ten nanometers as individually resolvable quantum systems. By developing a
stochastic optical reconstruction microscopy (STORM) technique for NV centers
we are able to simultaneously perform sub diffraction-limit imaging and
optically detected spin resonance (ODMR) measurements on NV spins. This allows
the assignment of spin resonance spectra to individual NV center locations with
nanometer scale resolution and thus further improves spatial discrimination.
For example, we resolved formerly indistinguishable emitters by their spectra.
Furthermore, ODMR spectra contain metrology information allowing for sub
diffraction-limit sensing of, for instance, magnetic or electric fields with
inherently parallel data acquisition. As an example, we have detected nuclear
spins with nanometer scale precision. Finally, we give prospects of how this
technique can evolve into a fully parallel quantum sensor for nanometer
resolution imaging of delocalized quantum correlations.",1404.1520v1
2014-05-06,Circuit-quantum electrodynamics with direct magnetic coupling to single-atom spin qubits in isotopically enriched 28Si,"Recent advances in silicon nanofabrication have allowed the manipulation of
spin qubits that are extremely isolated from noise sources, being therefore the
semiconductor equivalent of single atoms in vacuum. We investigate the
possibility of directly coupling an electron spin qubit to a superconducting
resonator magnetic vacuum field. By using resonators modified to increase the
vacuum magnetic field at the qubit location, and isotopically purified 28Si
substrates, it is possible to achieve coupling rates faster than the single
spin dephasing. This opens up new avenues for circuit-quantum electrodynamics
with spins, and provides a pathway for dispersive read-out of spin qubits via
superconducting resonators.",1405.1231v2
2014-08-20,Effects of interaction on field-induced resonances in confined Fermi liquid,"We consider the two-dimensional electron gas confined laterally to a narrow
channel by a harmonic potential. As the Zeeman splitting matches the
intersubband separation the nonlocal spin polarization develops a minimum as
reported by Frolov et al. [Nature (London) 458, 868 (2009)]. This phenomenon
termed Ballistic Spin Resonance is due to the degeneracy between the nearest
oppositely polarized subbands that is lifted by spin-orbit coupling. We showed
that the resonance survives the weak and short-range interaction. The latter
detunes it and as a result shifts the Zeeman splitting at which the minimum in
spin polarization occurs. Here this shift is attributed to the absence of Kohn
theorem for the spin sloshing collective mode. We characterized the shift due
to weak interaction qualitatively by analyzing the spin sloshing mode within
the Fermi liquid phenomenology.",1408.4707v2
2014-12-25,Normal-mode splitting in the coupled system of hybridized nuclear magnons and microwave photons,"In the weak ferromagnetic MnCO$_3$ system, a low-frequency collective spin
excitation (magnon) is the hybridized oscillation of nuclear and electron spins
coupled through the hyperfine interaction. By using a split-ring resonator, we
performed transmission spectroscopy measurements of MnCO$_3$ system and
observed, for the first time, avoiding crossing between the hybridized
nuclear-electron magnon mode and the resonator mode in the NMR-frequency range.
The splitting strength is quite large due to the large spin density of
$^{55}$Mn, and the cooperativity value $C=0.2$ (magnon-photon coupling
parameter) is close to the conditions of strong coupling. The results reveal a
new class of spin systems, in which the coupling between nuclear spins and
photons is mediated by electron spins via the hyperfine interaction, and in
which the similar normal-mode splitting of the hybridized nuclear magnon mode
and the resonator mode can be observed.",1412.7799v3
2015-03-09,Hybrid quantum device based on NV centers in diamond nanomechanical resonators plus superconducting waveguide cavities,"We propose and analyze a hybrid device by integrating a microscale diamond
beam with a single built-in nitrogen-vacancy (NV) center spin to a
superconducting coplanar waveguide (CPW) cavity. We find that under an ac
electric field the quantized motion of the diamond beam can strongly couple to
the single cavity photons via dielectric interaction. Together with the strong
spin-motion interaction via a large magnetic field gradient, it provides a
hybrid quantum device where the dia- mond resonator can strongly couple both to
the single microwave cavity photons and to the single NV center spin. This
enables coherent information transfer and effective coupling between the NV
spin and the CPW cavity via mechanically dark polaritons. This hybrid
spin-electromechanical de- vice, with tunable couplings by external fields,
offers a realistic platform for implementing quantum information with single NV
spins, diamond mechanical resonators, and single microwave photons.",1503.02437v2
2015-08-27,Dephasing due to nuclear spins in large-amplitude electric dipole spin resonance,"We have analyzed effects of the hyperfine interaction on electric dipole spin
resonance when the amplitude of the quantum-dot motion becomes comparable or
larger than the quantum dot's size. Away from the well known small-drive
regime, the important role played by transverse nuclear fluctuations leads to a
gaussian decay with characteristic dependence on drive strength and detuning. A
characterization of spin-flip gate fidelity, in the presence of such additional
drive-dependent dephasing, shows that vanishingly small errors can still be
achieved at sufficiently large amplitudes. Based on our theory, we analyze
recent electric-dipole spin resonance experiments relying on spin-orbit
interactions or the slanting field of a micromagnet. We find that such
experiments are already in a regime with significant effects of transverse
nuclear fluctuations and the form of decay of the Rabi oscillations can be
reproduced well by our theory.",1508.06894v2
2016-02-11,Laser-Driven Multiferroics and Ultrafast Spin Current Generation,"We propose an ultrafast way to generate spin chirality and spin current in a
class of multiferroic magnets using a terahertz circularly polarized laser.
Using the Floquet formalism for periodically driven systems, we show that it is
possible to dynamically control the Dzyaloshinskii-Moriya interaction in
materials with magnetoelectric coupling. This is supported by numerical
calculations, by which additional resonant phenomena are found. Specifically,
when a static magnetic field is applied in addition to the circularly polarized
laser, a large resonant enhancement of spin chirality is observed resembling
the electron spin resonance. Spin current is generated when the laser is
spatially modulated by chiral plasmonic structures and could be detected using
optospintronic devices.",1602.03702v2
2017-12-27,Spin Filtering via Resonant Reflection of Relativistic Surface States,"A microscopic approach is developed to scattering of surface states from a
non-magnetic linear defect at a surface with strong spin-orbit interaction.
Spin-selective reflection resonances in scattering of Rashba-split surface
states by an atomic stripe are theoretically discovered in a proof-of-principle
calculation for a model crystal potential. Spin-filtering properties of such
linear defects are analyzed within an envelope-function formalism for a
perturbed surface based on the Rashba Hamiltonian. The continuous Rashba model
is found to be in full accord with the microscopic theory, which reveals the
essential physics behind the scattering resonance. The spin-dependent
reflection suggests a novel mechanism to manipulate spins on the nanoscale.",1712.09593v1
2018-01-31,Proposal for detecting nodal-line semimetal surface-states with resonant spin-flipped reflection,"Topological nodal-line semimetals are predicted to exhibit unique
drumhead-like surface states (DSS). Yet, a direct detection of such states
remains a challenge. Here, we propose spin-resolved transport in a junction
between a normal metal and a spin-orbit coupled nodal-line semimetal as the
mechanism for their detection. Specifically, we find that in such a device, the
DSS induce resonant spin-flipped reflection. This effect can be probed by both
vertical spin transport and lateral charge transport between anti-parallel
magnetic terminals. In the tunneling limit of the junction, both spin and
charge conductances exhibit a resonant peak around zero energy, providing a
unique evidence of the DSS. This signature is robust to both dispersive DSS and
interface disorder. Based on numerical calculations, we show that the scheme
can be implemented in the topological semimetal HgCr$_2$Se$_4$.",1801.10337v3
2018-05-21,Dynamical suppression of tunneling and spin switching of a spin-orbit-coupled atom in a double-well trap,"We predict wide-band suppression of tunneling of spin-orbit-coupled atoms (or
noninteracting Bose-Einstein condensate) in a double-well potential with
periodically varying depths of the potential wells. The suppression of
tunneling is possible for a single state and for superposition of two states,
i.e. for a qbit. By varying spin-orbit coupling one can drastically increase
the range of modulation frequencies in which an atom remains localized in one
of the potential wells, the effect connected with crossing of energy levels.
This range of frequencies is limited because temporal modulation may also
excite resonant transitions between lower and upper states in different wells.
The resonant transitions enhance tunneling and are accompanied by pseudo-spin
switching. Since the frequencies of the resonant transitions are independent of
potential modulation depth, in contrast to frequencies at which suppression of
tunneling occurs, by varying this depth one can dynamically control both
spatial localization and pseudo-spin of the final state.",1805.07961v1
2018-12-19,Electron Spin Resonance on the spin-1/2 triangular magnet NaYbS2,"The delafossite structure of NaYbS2 contains a planar spin-1/2 triangular
lattice of Yb3+ ions and features a possible realisation of a quantum
spin-liquid state. We investigated the Yb3+ spin dynamics by Electron Spin
Resonance (ESR) in single-crystalline samples of NaYbS2. Very clear spectra
with a well-resolved and large anisotropy could be observed down to the lowest
accessible temperature of 2.7 K. In contrast to the ESR properties of other
known spin-liquid candidate systems, the resonance seen in NaYbS2 is accessible
at low fields (< 1T) and is narrow enough for accurate characterisation of the
relaxation rate as well as the g factor of the Yb3+ spins.",1812.07871v1
2018-12-19,Electric dipole spin resonance at shallow donors in quantum wires,"Electric dipole spin resonance is studied theoretically at a shallow donor
formed in a nanowire with spin-orbit coupling in a magnetic field. Such system
may represent a donor-based qubit. The single discrete energy level of the
donor is accompanied by the set of continuum states, which provide a
non-trivial interplay for the picture of electric dipole spin resonance driven
by an external monochromatic field. Strongly nonlinear dependencies of spin
flip time as well as of the coordinate mean values on the electric field
amplitude are observed, demonstrating the significance of coupling to the
continuum for spin-based qubits manipulation in nanostructures.",1812.08048v2
2018-04-10,Force-detected high-frequency electron spin resonance spectroscopy using magnet-mounted nanomembrane: robust detection of thermal magnetization modulation,"In this study, we report a conceptually novel broadband high-frequency
electron spin resonance (HFESR) spectroscopic technique. In contrast to the
ordinary force-detected ESR technique, which detects the magnetization change
due to the saturation effect, this method measures the magnetization change due
to the change of the sample temperature at resonance. To demonstrate its
principle, we developed a silicon nitride nanomembrane-based force-detected ESR
spectrometer, which can be stably operated even at high magnetic fields. Test
measurements were performed for samples with different spin relaxation times.
We succeeded in obtaining a seamless ESR spectrum in magnetic fields of 15~T
and frequencies of 636~GHz without significant spectral distortion. A high spin
sensitivity of $10^{12}$~spins/G$\cdot$s was obtained, which was independent of
the spin relaxation time. These results show that this technique can be used as
a practical method in research fields where the HFESR technique is applicable.",1804.03345v3
2021-10-21,Cavity Quantum Electrodynamics Effects with Nitrogen Vacancy Center Spins in Diamond and Microwave Resonators at Room Temperature,"Cavity quantum electrodynamics (C-QED) effects, such as Rabi splitting, Rabi
oscillations and superradiance, have been demonstrated with nitrogen vacancy
center spins in diamond in microwave resonators at cryogenic temperature. In
this article we explore the possibility to realize strong collective coupling
and the resulting C-QED effects with ensembles of spins at room temperature.
Thermal excitation of the individual spins by the hot environment leads to
population of collective Dicke states with low symmetry and a reduced
collective spin-microwave field coupling. However, we show with simulations
that the thermal excitation can be compensated by spin-cooling via optical
pumping. The resulting population of Dicke states with higher symmetry implies
strong coupling with currently available high-quality resonators and enables
C-QED effects at room temperature with potential applications in quantum
sensing and quantum information processing.",2110.10950v1
2008-06-13,Influence of dephasing process on the quantum Hall effect and the spin Hall effect,"We study the influence of the phase relaxation process on Hall resistance and
spin Hall current of a mesoscopic two-dimensional (2D) four-terminal Hall
cross-bar with or without Rashba spin-orbit interaction (SOI) in a
perpendicular uniform magnetic field. We find that the plateaus of the Hall
resistance with even number of edge states can survive for very strong phase
relaxation when the system size becomes much longer than the phase coherence
length. On the other hand, the odd integer Hall resistance plateaus arising
from the SOI are easily destroyed by the weak phase relaxation during the
competition between the magnetic field and the SOI which delocalize the edge
states. In addition, we have also studied the transverse spin Hall current and
found that it exhibits resonant behavior whenever the Fermi level crosses the
Landau band of the system. The phase relaxation process weakens the resonant
spin Hall current and enhances the non-resonant spin Hall current.",0806.2173v1
2017-03-30,Study of spin pumping in Co thin film vis-a-vis seed and capping layer using ferromagnetic resonance spectroscopy,"We investigated the dependence of the seed [Ta/Pt, Ta/Au] and capping [Pt/Ta,
Au/Ta] layers on spin pumping effect in the ferromagnetic 3 nm thick Co thin
film using ferromagnetic resonance spectroscopy. The data is fitted with Kittel
equation to evaluate damping constant and g-factor. A strong dependence of seed
and capping layers on spin pumping has been discussed. The value of damping
constant {alpha} is found to be relatively large i.e. 0.0326 for the
Ta{3}/Pt{3}/Co{3}/Pt{3}/Ta{3} {nm} multi-layer structure, while it is 0.0104
for Ta{3}/Co{3}/Ta{3} {nm}. Increase in {alpha} is observed due to Pt layer
that works as a good sink for spins due to high spin orbit coupling. In
addition, we measured the effective spin conductance = 2.0e18 m-2 for the
trilayer structure Pt{3}/Co{3}/Pt{3} {nm} as a result of the enhancement in
{alpha} relative to its bulk value. We observed that the evaluated g-factor
decreases as effective demagnetizing magnetic field increases in all the
studied samples. The azimuthal dependence of magnetic resonance field and line
width showed relatively high anisotropy in the trilayer Ta{3}/Co{3}/Ta{3} {nm}
structure.",1703.10630v1
2021-03-10,Quantum sensitivity limits of nuclear magnetic resonance experiments searching for new fundamental physics,"Nuclear magnetic resonance is a promising experimental approach to search for
ultra-light axion-like dark matter. Searches such as the cosmic axion
spin-precession experiments (CASPEr) are ultimately limited by
quantum-mechanical noise sources, in particular, spin-projection noise. We
discuss how such fundamental limits can potentially be reached. We consider a
circuit model of a magnetic resonance experiment and quantify three noise
sources: spin-projection noise, thermal noise, and amplifier noise. Calculation
of the total noise spectrum takes into account the modification of the circuit
impedance by the presence of nuclear spins, as well as the circuit back-action
on the spin ensemble. Suppression of the circuit back-action is especially
important in order for the spin-projection noise limits of searches for
axion-like dark matter to reach the quantum chromodynamic axion sensitivity.",2103.06284v1
2021-10-31,Electron-Spin-Resonance in a proximity-coupled MoS2/Graphene van-der-Waals heterostructure,"Coupling graphene's excellent electron and spin transport properties with
higher spin-orbit coupling material allows tackling the hurdle of spin
manipulation in graphene, due to the proximity to van-der-Waals layers. Here we
use magneto transport measurements to study the electron spin resonance on a
combined system of graphene and MoS2 at 1.5K. The electron spin resonance
measurements are performed in the frequency range of 18-33GHz, which allows us
to determine the g-factor in the system. We measure average g-factor of 1.91
for our hybrid system which is a considerable shift compared to what is
observed in graphene on SiO2. This is a clear indication of proximity induced
SOC in graphene in accordance with theoretical predictions.",2111.00530v2
2021-11-17,Large photogalvanic spin current by magnetic resonance in bilayer Cr trihalides,"Magnetic materials show rich optical responses related to the magnetic order.
These phenomena reflect the nature of their excitations, providing a powerful
probe for the magnetic states and a way to control them. In recent years, such
studies were extended to the optical control of spin current using nonlinear
optical response similar to the photogalvanic effect. However, neither a
candidate material nor a general formula for calculating the photogalvanic spin
current is known so far. In this work, we develop a general theory for the
photogalvanic spin current through a magnetic resonance process. Using the
nonlinear response formalism, we find the nonlinear conductivity consists of
two contributions that involve one and two magnon bands; the latter is a
contribution unknown to date. We argue that the two-band process produces a
large photogalvanic spin current in the antiferromagnetic phase of bilayer
CrI$_3$ and CrBr$_3$, whose resonance frequency can be tuned between GHz-THz
range by an external magnetic field. Our findings open a route to the studies
on the photogalvanic effect of spin angular momentum in realistic setups.",2111.09007v1
2022-01-04,Enhanced coupling of electron and nuclear spins by quantum tunneling resonances,"Noble-gas spins feature hours long coherence times owing to their great
isolation from the environment, and find practical usage in various
applications. However, this isolation leads to extremely slow preparation
times, relying on weak spin transfer from an electron-spin ensemble. Here we
propose a controllable mechanism to enhance this transfer rate. We analyze the
spin dynamics of helium-3 atoms with hot, optically-excited potassium atoms and
reveal the formation of quasi-bound states in resonant binary collisions. We
find a resonant enhancement of the spin-exchange cross section by up to six
orders of magnitude and two orders of magnitude enhancement for the thermally
averaged, polarization rate-coefficient. We further examine the effect for
various other noble gases and find that the enhancement is universal. We
outline feasible conditions under which the enhancement may be experimentally
observed and practically utilized.",2201.01255v1
2022-03-11,Rotational viscosity in spin resonance of hydrodynamic electrons,"In novel ultra-pure materials electrons can form a viscous fluid, which is
fundamentally different by its dynamics from the electron gas in ordinary
conductors with significant density of defects. The shape of the non-stationary
flow of such electron fluid is similar to the alternating flow of blood in
large-radius arteries [J. R. Womersley, J. Physiol. 127, 552 (1955)]. The
rotational viscosity effect is responsible for interconnection between the
dynamics of electron spins and flow inhomogeneities. In particular, it induces
the spin polarization of electrons in a curled flow via an internal spin-orbit
torque acting on electron spins. Here we show that this effect in an electron
fluid placed in a magnetic field leads to a correction to the ac sample
impedance, which has a resonance at the Larmor frequency of electrons. In this
way, via the electrically detected spin resonance the Womersley flow of an
electron fluid can be visualized and the rotational viscosity can be measured.",2203.06070v4
2022-10-19,Spatially Resolving Electron Spin Resonance of $π$-Radical in Single-molecule Magnet,"The spintronic properties of magnetic molecules have attracted significant
scientific attention. Special emphasis has been placed on the qubit for quantum
information processing. The single molecule magnet, bis(phthalocyaninato (Pc))
Tb(III) (TbPc2), is one of the best examined cases in which the delocalized
{\pi}-radical electron spin of the Pc ligand plays the key role in reading and
intermediating the localized Tb spin qubits. We utilized the electron spin
resonance (ESR) technique implemented on scanning tunneling microscope (STM)
and use it to measure local ESR of single TbPc2 molecule decoupled from the
Cu(100) substrate by 2 monolayers NaCl film to identify the {\pi}-radical spin.
We detected the ESR signal at the ligand positions at the resonance condition
expected for the S = 1/2 spin. The results reveal that the {\pi}-radical
electron is delocalized within the ligands and exhibits intramolecular coupling
susceptible to the chemical environment.",2210.10235v2
2023-03-06,Phase driving hole spin qubits,"The spin-orbit interaction in spin qubits enables spin-flip transitions,
resulting in Rabi oscillations when an external microwave field is resonant
with the qubit frequency. Here, we introduce an alternative driving mechanism
of hole spin qubits, where a far-detuned oscillating field couples to the qubit
phase. Phase driving at radio frequencies, orders of magnitude slower than the
microwave qubit frequency, induces highly non-trivial spin dynamics, violating
the Rabi resonance condition. By using a qubit integrated in a silicon fin
field-effect transistor (Si FinFET), we demonstrate a controllable suppression
of resonant Rabi oscillations, and their revivals at tunable sidebands. These
sidebands enable alternative qubit control schemes using global fields and
local far-detuned pulses, facilitating the design of dense large-scale qubit
architectures with local qubit addressability. Phase driving also decouples
Rabi oscillations from noise, an effect due to a gapped Floquet spectrum and
can enable Floquet engineering high-fidelity gates in future quantum
processors.",2303.03350v1
2024-03-18,High-Fidelity Entangling Gates for Electron and Nuclear Spin Qubits in Diamond,"Motivated by the recent experimental progress in exploring the use of a
nitrogen-vacancy (NV) center in diamond as a quantum computing platform, we
propose schemes for fast and high-fidelity entangling gates on this platform.
Using both analytical and numerical calculations, we demonstrate that
synchronization effects between resonant and off-resonant transitions may be
exploited such that spin-flip errors due to strong driving may be eliminated by
adjusting the gate time or the driving field. This allows for fast, high
fidelity entangling operations between the electron spin and one or several
nuclear spins. We investigate a two-qubit system where the NV center is
comprised of a $^{15}$N atom and a qubit-qutrit system for the case of a
$^{14}$N atom. In both cases, we predict a complete suppression of off-resonant
driving errors for two-qubit gates when addressing the NV electron spin
conditioned on states of nuclear spins of the nitrogen atom of the defect.
Additionally, we predict fidelities $>0.99$ for multi-qubit gates when
including the surrounding $^{13}$C atoms in the diamond lattice in the
conditioned logic.",2403.11553v1
2014-08-05,Collective Mode at Lifshitz Transition in Iron-Pnictide Superconductors,"We obtain the exact low-energy spectrum of two mobile holes in a t-J model
for an isolated layer in an iron-pnictide superconductor. The minimum d xz and
d yz orbitals per iron atom are included, with no hybridization between the
two. After tuning the Hund coupling to a putative quantum critical point (QCP)
that separates a commensurate spin-density wave from a hidden-order
antiferromagnet at half filling, we find an s-wave hole-pair groundstate and a
d-wave hole-pair excited state. Near the QCP, both alternate in sign between
hole Fermi surface pockets at the Brillouin zone center and emergent electron
Fermi surface pockets at momenta that correspond to commensurate spin-density
waves (cSDW). The dependence of the energy splitting with increasing Hund
coupling yields evidence for a true QCP in the thermodynamic limit near the
putative one, at which the s-wave and d-wave Cooper pairs are degenerate. A
collective s-to-d-wave oscillation of the macroscopic superconductor that
couples to orthorhombic shear strain is also identified. Its resonant frequency
is predicted to collapse to zero at the QCP in the limit of low hole
concentration. This implies degeneracy of Cooper pairs with s, d and s+id
symmetry in the corresponding quantum critical state. We argue that the
critical state describes Cooper pairs in hole-doped iron superconductors at the
Lifshitz transition, where electron bands first rise above the Fermi level. We
thereby predict that the s-to-d-wave collective mode observed by Raman
spectroscopy in Ba1-xKxFe2As2 at optimal doping should also be observed at
higher doping near the Lifshitz transition.",1408.0864v4
2018-07-24,Electrical manipulation of semiconductor spin qubits within the g-matrix formalism,"We discuss the modeling of the electrical manipulation of spin qubits in the
linear-response regime where the Rabi frequency is proportional to the magnetic
field and to the radio-frequency electric field excitation. We show that the
Rabi frequency can be obtained from a generalized g-tensor magnetic resonance
formula featuring a g-matrix and its derivative g' with respect to the electric
field (or gate voltage) as inputs. These matrices can be easily calculated from
the wave functions of the qubit at zero magnetic field. The g-matrix formalism
therefore provides the complete dependence of the Larmor and Rabi frequencies
on the orientation of the magnetic field at very low computational cost. It
also provides a compact model for the control of the qubit, and a simple
framework for the analysis of the effects of symmetries on the anisotropy of
the Larmor and Rabi frequencies. The g-matrix formalism applies to a wide
variety of electron and hole qubits, and we focus on a hole qubit in a
silicon-on-insulator nanowire as an illustration. We show that the Rabi
frequency of this qubit shows a complex dependence on the orientation of the
magnetic field, and on the gate voltages that control the symmetry of the hole
wave functions. We point out that the qubit may be advantageously switched
between two bias points, one where it can be manipulated efficiently, and one
where it is largely decoupled from the gate field but presumably longer lived.
We also discuss the role of residual strains in such devices in relation to
recent experiments.",1807.09185v2
2015-11-02,"Effects of Rashba spin-orbit coupling, Zeeman splitting and gyrotropy in two-dimensional cavity polaritons under the influence of the Landau quantization","GaAs-type quantum wells (QWs) with p-type valence band embedded into the
resonators. The Landau quantization of the electrons and heavy-holes (hh) was
investigated taking into account the Rashba spin-orbit coupling with
third-order chirality terms for hh and with nonparabolicity terms in their
dispersion low including the Zeeman splitting (ZS) effects. The exact solutions
for the eigenfunctions and eigenenergies were obtained using the Rashba method
[1]. We derive in the second quantization representation the Hamiltonians
describing the Coulomb electron-electron and the electron-radiation
interactions and determine the magnetoexciton energy branches and the
magnetoexciton-photon interaction. The fifth order dispersion equation
describing the energy spectrum of the cavity magnetoexciton-polariton is
investigated. It takes into account the interaction of the cavity photons with
two dipole-active and with two quadrupole-active 2D magnetoexciton energy
branches. The cavity photons have the circular polarizations oriented along
their wave vectors, which has the quantized longitudinal component. The
selection rules of the exciton-photon interaction is expressed through the
scalar products of the two-types circular polarizations and it is related with
the numbers of the LQ levels of electrons and heavy-holes. It is shown that the
Rabi frequency of the polariton branches and the magnetoexciton oscillator
strength increase in dependence on the magnetic field strength. The optical
gyrotropy effects may be revealed if changing the sign of the photon circular
polarization at a given sign of the wave vector longitudinal projection or
equivalently changing the sign of the longitudinal projection at the same
selected light circular polarization.",1603.09571v1
2022-03-30,Optimisation of electrically-driven multi-donor quantum dot qubits,"Multi-donor quantum dots have been at the forefront of recent progress in
Si-based quantum computation. Among them, $2P:1P$ qubits have a built-in dipole
moment, enabling all-electrical spin operation via hyperfine mediated electron
dipole spin resonance (EDSR). The development of all-electrical multi-donor dot
qubits requires a full understanding of their EDSR and coherence properties,
incorporating multi-valley nature of their ground state. Here, by introducing a
variational effective mass wave-function, we examine the impact of qubit
geometry and nearby charge defects on the electrical operation and coherence of
$2P:1P$ qubits. We report four outcomes: (i) The difference in the hyperfine
interaction between the $2P$ and $1P$ sites enables fast EDSR, with $T_\pi \sim
10-50$ ns and a Rabi ratio $ (T_1/T_\pi) \sim 10^6$. We analyse qubits with the
$2P:1P$ axis aligned along the [100], [110] and [111] crystal axes, finding
that the fastest EDSR time $T_\pi$ occurs when the $2P:1P$ axis is
$\parallel$[111], while the best Rabi ratio occurs when it is $\parallel$
[100]. This difference is attributed to the difference in the wave function
overlap between $2P$ and $1P$ for different geometries. In contrast, the choice
of $2P$ axis has no visible impact on qubit operation. (ii) Sensitivity to
random telegraph noise due to nearby charge defects depends strongly on the
location of the nearby defects with respect to the qubit. For certain
orientations of defects random telegraph noise has an appreciable effect both
on detuning and $2P-1P$ tunneling, with the latter inducing gate errors. (iii)
The qubit is robust against $1/f$ noise provided it is operated away from the
charge anticrossing. (iv) Entanglement via exchange is several orders of
magnitude faster than dipole-dipole coupling. These findings pave the way
towards fast, low-power, coherent and scalable donor dot-based quantum
computing.",2203.16553v1
2023-01-28,Proximity-enhanced valley Zeeman splitting at the WS$_2$/graphene interface,"The valley Zeeman physics of excitons in monolayer transition metal
dichalcogenides provides valuable insight into the spin and orbital degrees of
freedom inherent to these materials. Being atomically-thin materials, these
degrees of freedom can be influenced by the presence of adjacent layers, due to
proximity interactions that arise from wave function overlap across the 2D
interface. Here, we report 60 T magnetoreflection spectroscopy of the A- and B-
excitons in monolayer WS$_2$, systematically encapsulated in monolayer
graphene. While the observed variations of the valley Zeeman effect for the A-
exciton are qualitatively in accord with expectations from the bandgap
reduction and modification of the exciton binding energy due to the
graphene-induced dielectric screening, the valley Zeeman effect for the B-
exciton behaves markedly different. We investigate prototypical WS$_2$/graphene
stacks employing first-principles calculations and find that the lower
conduction band of WS$_2$ at the $K/K'$ valleys (the $CB^-$ band) is strongly
influenced by the graphene layer on the orbital level. This leads to variations
in the valley Zeeman physics of the B- exciton, consistent with the
experimental observations. Our detailed microscopic analysis reveals that the
conduction band at the $Q$ point of WS$_2$ mediates the coupling between $CB^-$
and graphene due to resonant energy conditions and strong coupling to the Dirac
cone. Our results therefore expand the consequences of proximity effects in
multilayer semiconductor stacks, showing that wave function hybridization can
be a multi-step process with different bands mediating the interlayer
interactions. Such effects can be exploited to resonantly engineer the
spin-valley degrees of freedom in van der Waals and moir\'e heterostructures.",2301.12234v1
2017-09-24,Double-negative acoustic metamaterials,"The aim of this paper is to provide a mathematical theory for understanding
the mechanism behind the double-negative refractive index phenomenon in bubbly
fluids. The design of double-negative metamaterials generally requires the use
of two different kinds of subwavelength resonators, which may limits the
applicability of double-negative metamaterials. Herein we rely on media that
consists of only a single type of resonant element, and show how to turn the
acoustic metamaterial with a single negative effective property obtained in [H.
Ammari and H. Zhang, Effective medium theory for acoustic waves in bubbly
fluids near Minnaert resonant frequency. SIAM J. Math. Anal., 49 (2017),
3252--3276.] into a negative refractive index metamaterial, which refracts
waves negatively, hence acting as a superlens. Using bubble dimers made of two
identical bubbles, it is proved that both the effective mass density and the
bulk modulus of the bubbly fluid can be negative near the anti-resonance of the
two hybridized Minnaert resonances for a single constituent bubble dimer. A
rigorous justification of the Minnaert resonance hybridization, in the case of
a bubble dimer in a homogeneous medium, is established. The acoustic properties
of a single bubble dimer are analyzed. Asymptotic formulas for the two
hybridized Minnaert resonances are derived. Moreover, it is proved that the
bubble dimer can be approximated by a point scatterer with monopole and dipole
modes. For an appropriate volume fraction of bubble dimers with certain
conditions on their configuration, a double-negative effective medium when the
frequency is near the anti-resonance of the hybridized Minnaert resonances can
be obtained.",1709.08177v2
2018-09-25,Connection between asymptotic normalization coefficients and resonance widths of mirror states,"Asymptotic normalization coefficients (ANCs) are fundamental nuclear
constants playing important role in nuclear reactions, nuclear structure and
nuclear astrophysics. In this paper a connection between ANCs and resonance
widths of the mirror states is established. Using Pinkston-Satchler equation
the ratio for resonance widths and ANCs of mirror nuclei is obtained in terms
of the Wronskians from the radial overlap functions and regular solutions of
the two-body Schr\""odinger equation with the short-range interaction excluded.
This ratio allows one to use microscopic overlap functions for mirror nuclei in
the internal region, where they are the most accurate, to correctly predict the
ratio of the resonance widths and ANCs for mirror nuclei, which determine the
amplitudes of the tails of the overlap functions. If the microscopic overlap
functions are not available one can express the Wronskians for the resonances
and mirror bound states in terms of the corresponding mirror two-body
potential-model wave functions. A further simplification of the Wronskians
ratio leads to the equation for the ratio of the resonance widths and mirror
ANCs, which is expressed in terms of the ratio of the two-body Coulomb
scattering wave functions at the resonance energy and at the binding energy [N.
K. Timofeyuk, R. C. Johnson, and A. M. Mukhamedzhanov, Phys. Rev. Lett. {\bf
91}, 232501 (2003]. In this paper calculations of the ratios of resonance
widths and mirror ANCs for different nuclei are presented. From this ratio one
can determine the resonance width if the mirror ANC is known and vice versa.
Comparison with available experimental ratios are done.",1809.09980v1
2020-12-02,A complex-valued resonance model for axisymmetric screech tones in supersonic jets,"We model the resonance mechanism underpinning generation of A1 and A2 screech
tones in an under-expanded supersonic jet. Starting from the resonance model
recently proposed by \cite{mancinelli2019screech}, where the
upstream-travelling wave is a neutrally-stable guided jet mode, we here present
a more complete linear-stability-based model for screech prediction. We study
temperature and shear-layer thickness effects and show that, in order to
accurately describe the experimental data, the effect of the finite thickness
of the shear layer must be incorporated in the jet-dynamics model. We then
present an improved resonance model for screech-frequency predictions in which
both downstream- and upstream-travelling waves may have complex wavenumber and
frequency. This resonance model requires knowledge of the reflection
coefficients at the upstream and downstream locations of the resonance loop. We
explore the effect of the reflection coefficients on the resonance model and
propose an approach for their identification. The complex-mode model identifies
limited regions of frequency-flow parameter space for which the resonance loop
is amplified in time, a necessary condition for the resonance to be sustained.
This model provides an improved description of the experimental measurements.",2012.01342v2
2017-11-21,Eavesdropping on spin waves inside the domain-wall nanochannel via three-magnon processes,"One recent breakthrough in the field of magnonics is the experimental
realization of reconfigurable spin-wave nanochannels formed by magnetic domain
wall with a width of $10-100$ nm [Wagner \emph{et al}., Nat. Nano. \textbf{11},
432 (2016)]. This remarkable progress enables an energy-efficient spin-wave
propagation with a well-defined wave vector along its propagating path inside
the wall. In the mentioned experiment, a micro-focus Brillouin light scattering
spectroscopy was taken in a line-scans manner to measure the frequency of the
bounded spin wave. Due to their localization nature, the confined spin waves
can hardly be detected from outside the wall channel, which guarantees the
information security to some extent. In this work, we theoretically propose a
scheme to detect/eavesdrop on the spin waves inside the domain-wall nanochannel
via nonlinear three-magnon processes. We send a spin wave in one magnetic
domain to interact with the bounded mode in the wall. Two kinds of three-magnon
processes, i.e., confluence and splitting, are expected to occur. The
confluence process is conventional. We predict a stimulated three-magnon
splitting (or ""magnon laser"") effect: the presence of a bound magnon
propagating along the domain wall channel assists the splitting of the incident
wave into two modes, one of which is identical to the bound mode in the
channel. Micromagnetic simulations confirm our theoretical analysis. These
results demonstrate that one is able to uniquely infer the spectrum of the
spin-wave in the domain-wall nanochannel once we know both the injection and
the transmitted waves.",1711.07615v2
2012-10-30,Spin-singlet Gaffnian wave function for fractional quantum Hall systems,"We characterize in detail a wave function conceivable in fractional quantum
Hall systems where a spin or equivalent degree of freedom is present. This wave
function combines the properties of two previously proposed quantum Hall wave
functions, namely the non-Abelian spin-singlet state and the nonunitary
Gaffnian wave function. This is a spin-singlet generalization of the
spin-polarized Gaffnian, which we call the ""spin-singlet Gaffnian"" (SSG). In
this paper we present evidence demonstrating that the SSG corresponds to the
ground state of a certain local Hamiltonian, which we explicitly construct,
and, further, we provide a relatively simple analytic expression for the unique
ground-state wave functions, which we define as the zero energy eigenstates of
that local Hamiltonian. In addition, we have determined a certain nonunitary,
rational conformal field theory which provides an underlying description of the
SSG and we thus conclude that the SSG is ungapped in the thermodynamic limit.
In order to verify our construction, we implement two recently proposed
techniques for the analysis of fractional quantum Hall trial states: The ""spin
dressed squeezing algorithm"", and the ""generalized Pauli principle"".",1210.8143v3
2024-01-31,Magnetic polarons beyond linear spin-wave theory: Mesons dressed by magnons,"When a mobile hole is doped into an antiferromagnet, its movement will
distort the surrounding magnetic order and yield a magnetic polaron. The
resulting complex interplay of spin and charge degrees of freedom gives rise to
very rich physics and is widely believed to be at the heart of high-temperature
superconductivity in cuprates. In this paper, we develop a quantitative
theoretical formalism, based on the phenomenological parton description, to
describe magnetic polarons in the strong coupling regime. We construct an
effective Hamiltonian with weak coupling to the spin-wave excitations in the
background, making the use of standard polaronic methods possible. Our starting
point is a single hole doped into an AFM described by a 'geometric string'
capturing the strongly correlated hopping processes of charge and spin degrees
of freedom, beyond linear spin-wave approximation. Subsequently, we introduce
magnon excitations through a generalized 1/S expansion and derive an effective
coupling of these spin-waves to the hole plus the string (the meson) to arrive
at an effective polaron Hamiltonian with density-density type interactions.
After making a Born-Oppenheimer-type approximation, this system is solved using
the self-consistent Born approximation to extract the renormalized polaron
properties. We apply our formalism (i) to calculate beyond linear spin-wave
ARPES spectra, (ii) to reveal the interplay of ro-vibrational meson
excitations, and (ii) to analyze the pseudogap expected at low doping.
Moreover, our work paves the way for exploring magnetic polarons out-of
equilibrium or in frustrated systems, where weak-coupling approaches are
desirable and going beyond linear spin-wave theory becomes necessary.",2402.00130v1
2012-12-20,The Dispersion Relations and Instability Thresholds of Oblique Plasma Modes in the Presence of an Ion Beam,"An ion beam can destabilize Alfv\'en/ion-cyclotron waves and
magnetosonic/whistler waves if the beam speed is sufficiently large. Numerical
solutions of the hot-plasma dispersion relation have previously shown that the
minimum beam speed required to excite such instabilities is significantly
smaller for oblique modes with $\vec k \times \vec B_0\neq 0$ than for
parallel-propagating modes with $\vec k \times \vec B_0 = 0$, where $\vec k$ is
the wavevector and $\vec B_0$ is the background magnetic field. In this paper,
we explain this difference within the framework of quasilinear theory, focusing
on low-$\beta$ plasmas. We begin by deriving, in the cold-plasma approximation,
the dispersion relation and polarization properties of both oblique and
parallel-propagating waves in the presence of an ion beam. We then show how the
instability thresholds of the different wave branches can be deduced from the
wave--particle resonance condition, the conservation of particle energy in the
wave frame, the sign (positive or negative) of the wave energy, and the wave
polarization. We also provide a graphical description of the different
conditions under which Landau resonance and cyclotron resonance destabilize
Alfv\'en/ion-cyclotron waves in the presence of an ion beam. We draw upon our
results to discuss the types of instabilities that may limit the differential
flow of alpha particles in the solar wind.",1212.5192v2
2004-06-09,Time-Dependent Spin-Polarized Transport Through a Resonant Tunneling Structure with Multi-Terminal,"The spin-dependent transport of the electrons tunneling through a resonant
tunneling structure with ferromagnetic multi-terminal under dc and ac fields is
explored by means of the nonequilibrium Green function technique. A general
formulation for the time-dependent current and the time-averaged current is
established. As its application the systems with two and three terminals in
noncollinear configurations of the magnetizations under dc and ac biases are
investigated, respectively. The asymmetric factor of the relaxation times for
the electrons with different spin in the central region is uncovered to bring
about various behaviours of the TMR. The present three-terminal device is
different from that discussed in literature, which is coined as a spin
transistor with source. The current-amplification effect is found. In addition,
the time-dependent spin transport for the two-terminal device is studied. It is
found that the photonic sidebands provide new channels for the electrons
tunneling through the barriers, and give rise to new resonances of the TMR,
which is called as the photon-asisted spin-dependent tunneling. The asymmetric
factor of the relaxation times is observed to lead to additional resonant peaks
besides the photon-asisted resonances.",0406221v1
2016-08-27,Impact of g-factors and valleys on spin qubits in a silicon double quantum dot,"We define single electron spin qubits in a silicon MOS double quantum dot
system. By mapping the qubit resonance frequency as a function of gate-induced
electric field, the spectrum reveals an anticrossing that is consistent with an
inter-valley spin-orbit coupling. We fit the data from which we extract an
inter-valley coupling strength of 43 MHz. In addition, we observe a narrow
resonance near the primary qubit resonance when we operate the device in the
(1,1) charge configuration. The experimental data is consistent with a
simulation involving two weakly exchanged-coupled spins with a g-factor
difference of 1 MHz, of the same order as the Rabi frequency. We conclude that
the narrow resonance is the result of driven transitions between the T- and T+
triplet states, using an ESR signal of frequency located halfway between the
resonance frequencies of the two individual spins. The findings presented here
offer an alternative method of implementing two-qubit gates, of relevance to
the operation of larger scale spin qubit systems.",1608.07748v2
2019-08-07,"Continuous monitoring of a trapped, superconducting spin","Readout and control of fermionic spins in solid-state systems are key
primitives of quantum information processing and microscopic magnetic sensing.
The highly localized nature of most fermionic spins decouples them from
parasitic degrees of freedom, but makes long-range interoperability difficult
to achieve. In light of this challenge, an active effort is underway to
integrate fermionic spins with circuit quantum electrodynamics (cQED), which
was originally developed in the field of superconducting qubits to achieve
single-shot, quantum-non-demolition (QND) measurements and long-range
couplings. However, single-shot readout of an individual spin with cQED has
remained elusive due to the difficulty of coupling a resonator to a particle
trapped by a charge-confining potential. Here we demonstrate the first
single-shot, cQED readout of a single spin. In our novel implementation, the
spin is that of an individual superconducting quasiparticle trapped in the
Andreev levels of a semiconductor nanowire Josephson element. Due to a
spin-orbit interaction inside the nanowire, this ""superconducting spin""
directly determines the flow of supercurrent through the element. We harnessed
this spin-dependent supercurrent to achieve both a zero-field spin splitting as
well as a long-range interaction between the quasiparticle and a
superconducting microwave resonator. Owing to the strength of this interaction
in our device, measuring the resultant spin-dependent resonator frequency
yielded QND spin readout with 92% fidelity in 1.9 $\mu$s and allowed us to
monitor the quasiparticle's spin in real time. These results pave the way for
new ""fermionic cQED"" devices: superconducting spin qubits operating at zero
magnetic field, devices in which the spin has enhanced governance over the
circuit, and time-domain measurements of Majorana modes.",1908.02800v1
2002-08-22,Electronic spin precession in semiconductor quantum dots with spin-orbit coupling,"The electronic spin precession in semiconductor dots is strongly affected by
the spin-orbit coupling. We present a theory of the electronic spin resonance
at low magnetic fields that predicts a strong dependence on the dot occupation,
the magnetic field and the spin-orbit coupling strength. Coulomb interaction
effects are also taken into account in a numerical approach.",0208425v1
2003-08-13,Nuclear spin relaxation probed by a single quantum dot,"We present measurements on nuclear spin relaxation probed by a single quantum
dot in a high-mobility electron gas. Current passing through the dot leads to a
spin transfer from the electronic to the nuclear spin system. Applying electron
spin resonance the transfer mechanism can directly be tuned. Additionally, the
dependence of nuclear spin relaxation on the dot gate voltage is observed. We
find electron-nuclear relaxation times of the order of 10 minutes.",0308243v1
2005-06-30,Magnon transport and spin current switching through quantum dots,"We study the nonequilibrium spin current through a quantum dot consisting of
two localized spin-1/2 coupled to two ferromagnetic insulators. The influence
of an intra-dot magnetic field and exchange coupling, different dot-reservoir
coupling configurations, and the influence of magnon chemical potential
differences vs. magnetic field gradients onto the spin current are examined. We
discuss various spin switching mechanisms and find that, in contrast to
electronic transport, the spin current is very sensitive to the specific
coupling configuration and band edges. In particular, we identify 1- and
2-magnon transport processes which can lead to resonances and antiresonances
for the spin current.",0506806v1
2005-10-16,Slow transverse relaxation of the Zn-neighbor Cu nuclear spins in YBa2(Cu{1-x}Znx)4O8,"An explanation is given for the recent observation in the plane-site Cu
nuclear quadrupole resonance (NQR) study of a heavily Zn-substituted
YBa$_2$(Cu$_{1-x}$Zn$_x$)$_4$O$_{8}$ that the Cu nuclear spin-spin relaxation
time $T_{2G}$ near the impurity Zn is longer than that away from Zn. The long
$T_{2G}$ of the Zn-neighbor Cu nuclear spins results from a distant coupling
between only a few nuclear spins near Zn, which does not indicate the absence
of local enhancement of the staggered spin susceptibility around Zn.",0510415v1
2005-12-16,Line Broadening and Decoherence of Electron Spins in Phosphorus-Doped Silicon Due to Environmental 29^Si Nuclear Spins,"Phosphorus-doped silicon single crystals with 0.19 % <= f <= 99.2 %, where f
is the concentration of 29^Si isotopes, are measured at 8 K using a pulsed
electron spin resonance technique, thereby the effect of environmental 29^Si
nuclear spins on the donor electron spin is systematically studied. The
linewidth as a function of f shows a good agreement with theoretical analysis.
We also report the phase memory time T_M of the donor electron spin dependent
on both f and the crystal axis relative to the external magnetic field.",0512404v1
2006-03-09,Spin Current and Current-Induced Spin Transfer Torque in Ferromagnet-Quantum Dot-Ferromagnet Coupled Systems,"Based on Keldysh's nonequilibrium Green function method, the spin-dependent
transport properties in a ferromagnet-quantum dot (QD)-ferromagnet coupled
system are investigated. It is shown the spin current shows quite different
characteristics from its electrical counterpart, and by changing the relative
orientation of both magnetizations, it can change its magnitude even sign. The
current-induced spin transfer torque (CISTT) is uncovered to be greatly
enhanced when the bias voltage meets with the discrete levels of the QD at
resonant positions. The relationship between the CISTT, the electrical current
and the spin current is also addressed.",0603235v1
2006-11-28,Generation of dc spin current in a narrow channel with Rashba and Dresselhaus spin-orbit interaction,"We consider a finite range ac-biased front gate acting upon a quantum channel
with Rashba and Dresselhaus spin-orbit interaction effects. The ac-biased gate,
giving rise to a dynamical Rashba coupling, causes spin-resolved coherent
resonant inelastic scattering. A pure dc spin current is subsequently generated
without accompanying charge current. In the presence of Dresselhaus effect, the
dc spin current is suppressed in the low kinetic energy regime but is assisted
in the high kinetic energy regime.",0611703v1
2007-01-28,Nuclear spin diffusion in the semiconductor TlTaS3,"We report on a 203Tl and 205Tl nuclear magnetic resonance study of the chain
ternary semiconductor TlTaS3. We show that spin-lattice relaxation in this
compound is driven by two contributions, namely by interactions of nuclear
spins with thermally activated carriers and with localized electron spins. The
latter mechanism dominates at lower temperature; at that, our measurements
provide striking manifestation of the spin-diffusion-limited relaxation regime.
The experimental data obtained allow us to estimate the spin diffusion
coefficient.",0701688v1
2007-02-26,Room Temperature Electrical Detection of Spin Coherence in C60,"An experimental demonstration of electrical detection of coherent spin motion
of weakly coupled, localized electron spins in thin Fullerene C60 films at room
temperature is presented. Pulsed electrically detected magnetic resonance
experiments on vertical photocurrents through Al/C60/ZnO samples showed that an
electron spin Rabi oscillation is reflected by transient current changes. The
nature of possible microscopic mechanisms responsible for this spin to charge
conversion as well as its implications for the readout of endohedral Fullerene
(N@C60) spin qubits are discussed.",0702604v1
2003-10-07,Minimization of nonresonant effects in a scalable Ising spin quantum computer,"The errors caused by the transitions with large frequency offsets
(nonresonant transitions) are calculated analytically for a scalable
solid-state quantum computer based on a one-dimensional spin chain with Ising
interactions between neighboring spins. Selective excitations of the spins are
enabled by a uniform gradient of the external magnetic field. We calculate the
probabilities of all unwanted nonresonant transitions associated with the flip
of each spin with nonresonant frequency and with flips of two spins: one with
resonant and one with nonresonant frequencies. It is shown that these errors
oscillate with changing the gradient of the external magnetic field. Choosing
the optimal values of this gradient allows us to decrease these errors by 50%.",0310049v1
2007-05-15,The Nuclear Spin Nanomagnet,"Linearly polarized light tuned slightly below the optical transition of the
negatively charged exciton (trion) in a single quantum dot causes the
spontaneous nuclear spin polarization (self-polarization) at a level close to
100%. The effective magnetic field of spin-polarized nuclei brings the optical
transition energy into resonance with photon energy. The resonantly enhanced
Overhauser effect sustains the stability of the nuclear self-polarization even
in the absence of spin polarization of the quantum dot electron. As a result
the optically selected single quantum dot represents a tiny magnet with the
ferromagnetic ordering of nuclear spins - the nuclear spin nanomagnet.",0705.2167v2
2007-11-21,Strain-assisted spin manipulating and the discerption of strain-induced spin splitting,"We show that the efficiency of manipulating electron spin in semiconductor
quantum wells can be enhanced by tuning the strain strength. The effect
combining intrinsic and strain-induced spin splitting varies for different
systems, which provides an alternative route to understand the experimental
phenomena brought in by the strain. The types of spin splittings caused by
strain are suggested to be distinguished by the measurement of the
electron-dipole-spin-resonance intensity through changing the direction of the
$ac$ electric field in the $x$-$y$ plane of the quantum well and tuning the
strain strengths.",0711.3378v1
2008-04-09,Electric field control of spin-orbit splittings in GaAs/AlGaAs coupled quantum wells,"Electron spin dynamics is investigated in n-i-n GaAs/AlGaAs coupled quantum
wells. The electron spin dephasing time is measured as a function of an
external electrical bias under resonant excitation of the 1sHH intrawell
exciton using a time-resolved Kerr rotation technique. It is found a strong
electron spin dephasing time anisotropy caused by an interference of the
structure inversion asymmetry and the bulk inversion asymmetry. This anisotropy
is shown to be controlled by an electrical bias. A theoretical analysis of
electron spin dephasing time anisotropy is developed. The ratio of Rashba and
Dresselhaus spin splittings is studied as a function of applied bias.",0804.1483v1
2008-05-05,Visualizing the spin of individual molecules,"Low-temperature spin-polarized scanning tunneling microscopy is employed to
study spin transport across single Cobalt-Phathalocyanine molecules adsorbed on
well characterized magnetic nanoleads. A spin-polarized electronic resonance is
identified over the center of the molecule and exploited to spatially resolve
stationary spin states. These states reflect two molecular spin orientations
and, as established by density functional calculations, originate from a
ferromagnetic molecule-lead superexchange interaction mediated by the organic
ligands.",0805.0485v1
2009-02-26,Qubit protection in nuclear-spin quantum dot memories,"We present a mechanism to protect quantum information stored in an ensemble
of nuclear spins in a semiconductor quantum dot. When the dot is charged the
nuclei interact with the spin of the excess electron through the hyperfine
coupling. If this coupling is made off-resonant it leads to an energy gap
between the collective storage states and all other states. We show that the
energy gap protects the quantum memory from local spin-flip and spin-dephasing
noise. Effects of non-perfect initial spin polarization and inhomogeneous
hyperfine coupling are discussed.",0902.4566v1
2009-06-20,Wavevector-dependent spin filtering and spin transport through magnetic barriers in graphene,"We study the spin-resolved transport through magnetic nanostructures in
monolayer and bilayer graphene. We take into account both the orbital effect of
the inhomogeneous perpendicular magnetic field as well as the in-plane spin
splitting due to the Zeeman interaction and to the exchange coupling possibly
induced by the proximity of a ferromagnetic insulator. We find that a single
barrier exhibits a wavevector-dependent spin filtering effect at energies close
to the transmission threshold. This effect is significantly enhanced in a
resonant double barrier configuration, where the spin polarization of the
outgoing current can be increased up to 100% by increasing the distance between
the barriers.",0906.3809v1
2009-07-01,Control of Spin Blockade by AC Magnetic Fields in Triple Quantum Dots,"We analyze coherent spin phenomena in triple quantum dots in triangular
configuration under crossed DC and AC magnetic fields. In particular, we
discuss the interplay between Aharonov-Bohm current oscillations, coherent
electron trapping and spin blockade under electron spin resonance conditions.
We demonstrate that, for certain field frequencies, AC magnetic fields induce
an antiresonant behavior in the current, allowing for both removal and
restoration of entangled spin blockaded states by tuning the AC field
frequency. Our theoretical predictions indicate how to manipulate spin qubits
in a triangular quantum dot array.",0907.0182v2
2011-06-15,Spin Scissors Mode and the Fine Structure of M1 States in Nuclei,"The coupled dynamics of low lying modes, including the scissors mode, and
various giant quadrupole resonances are studied with the help of the Wigner
Function Moments method generalized to take into account spin degrees of
freedom. Equations of motion for collective variables are derived on the basis
of Time Dependent Hartree-Fock equations in the model of harmonic oscillator
with spin orbital mean field potential plus quadrupole-quadrupole residual
interaction. Introducing spin allows one to consider new types of nuclear
collective motion where the nucleons with spin 'up' oscillate against nucleons
with spin 'down'.",1106.2963v1
2012-07-29,Squeezing of Collective Excitations in Spin Ensembles,"We analyse the possibility to create two-mode spin squeezed states of two
separate spin ensembles by inverting the spins in one ensemble and allowing
spin exchange between the ensembles via a near resonant cavity field. We
investigate the dynamics of the system using a combination of numerical and
analytic calculations, and we obtain squeezing for a wide range of parameters.
We also investigate the transfer of the squeezing properties to the cavity
field and to an output mode from the cavity. Finally, we investigate how the
squeezing is affected by effects of inhomogeneities which would be present in
solid state implementations of the spin ensembles.",1207.6772v1
2012-08-02,Stimulated emission of radiation using spin-population inversion in metals: a spin-laser,"Arrays of 10 nm-diameter point contacts of exchange-coupled
spin-majority/spin-minority ferromagnetic metals, integrated into
infrared-terahertz range photon resonators, are fabricated and measured
electrically and optically. Giant, threshold-type electronic excitations under
high-current pumping of the devices are observed as abrupt but reversible steps
in device resistance, in many cases in access of 100%, which correlate with
optical emission from the devices. The results are interpreted as due to
stimulated spin-flip electron-photon relaxation in the system.",1208.0550v2
2012-08-15,Gate voltage control over spin relaxation length,"Spin currents in channels of a high mobility GaAs/AlGaAs two-dimensional
electron gas are generated and detected using spin-polarized quantum point
contacts. We have recently shown that the relaxation length of spin currents is
resonantly suppressed when the frequency at which electrons bounce between
channel walls matches the Larmor frequency. Here we demonstrate that a gate on
top of the channel tunes such ballistic spin resonance by tuning the velocity
of electrons and hence the bouncing frequency. These findings demonstrate a new
mechanism for electrical control of spin logic circuits.",1208.3106v1
2012-10-18,Spin-blockade qubit in a superconducting junction,"We interpret a recent pioneering experiment [Zgirski M. et al., Phys. Rev.
Lett., 106 (2011) 257003] on quasiparticle manipulation in a superconducting
break junction in terms of spin blockade drawing analogy with spin qubits. We
propose a novel qubit design that exploits the spin state of two trapped
quasiparticles. We detail the coherent control of all four spin states by
resonant quantum manipulation and compute the corresponding Rabi frequencies.
The read-out technique is based on the spin-blockade that inhibits
quasiparticle recombination in triplet states. We provide extensive microscopic
estimations of the parameters of our model.",1210.5151v1
2014-07-08,Spin Orbit Coupling in Periodically Driven Optical Lattices,"We propose a method for the emulation of artificial spin orbit coupling in a
system of ultracold, neutral atoms trapped in a tight-binding lattice. This
scheme does not involve near-resonant laser fields, avoiding the heating
processes connected to the spontaneous emission of photons. In our case, the
necessary spin dependent tunnel matrix elements are generated by a rapid, spin
dependent, periodic force, which can be described in the framework of an
effective, time averaged Hamiltonian. An additional radio frequency coupling
between the spin states leads to a mixing of the spin bands.",1407.1953v2
2014-07-29,Quantum Model Of Spin Noise,"Any ensemble of quantum particles exhibits statistical fluctuations known as
spin noise. Here, we provide a description of spin noise in the language of
open quantum systems. The description unifies the signatures of spin noise
under both strong and weak measurements. Further, the model accounts for
arbitrary spin dynamics from an arbitrary initial state. In all cases we can
find both the spin noise and its time correlation function.",1407.7620v2
2016-03-24,Semiclassical Landau quantization of spin-orbit coupled systems,"A semiclassical quantization condition is derived for Landau levels in
general spin-orbit coupled systems. This generalizes the Onsager quantization
condition via a matrix-valued phase which describes spin dynamics along the
classical cyclotron trajectory. We discuss measurement of the matrix phase via
magnetic oscillations and electron spin resonance, which may be used to probe
the spin structure of the precessing wavefunction. We compare the resulting
semiclassical spectrum with exact results which are obtained for a variety of
spin-orbit interactions in 2D systems.",1603.07450v1
2020-03-29,Long-term spin state storage using ancilla charge memories,"We articulate confocal microscopy and electron spin resonance to implement
spin-to-charge conversion in a small ensemble of nitrogen-vacancy (NV) centers
in bulk diamond, and demonstrate charge conversion of neighboring defects
conditional on the NV spin state. We build on this observation to show
time-resolved NV spin manipulation and ancilla-charge-aided NV spin state
detection via integrated measurements. Our results hint at intriguing
opportunities in the search for enhanced forms of color-center-based metrology
and information processing down to the limit of individual point defects.",2003.13148v1
2019-10-13,Spin excitations in nickelate superconductors,"We study theoretically spin excitations in the newly discovered nickelate
superconductors based on a single-band model and the random phase
approximation. The spin excitations are found to be incommensurate in a low
energy region. A spin resonance phenomena is revealed as the excitation energy
increases. The maximum intensity may be at the incommensurate momentum or the
commensurate momentum, depending on the out-of-plane momentum. The spin
excitations become incommensurate again at higher energies. The similarities
and differences of the spin excitations between nickelate and cuprate
superconductors are addressed. Our predicted results can be tested by inelastic
neutron scattering experiments later.",1910.05757v2
2019-12-24,Large spin Hall angle and spin mixing conductance in highly resistive antiferromagnetic Mn2Au,"Antiferromagnetic (AFM) materials recently have shown interest in the
research in spintronics due to its zero stray magnetic field, high anisotropy,
and spin orbit coupling. In this context, the bi-metallic AFM Mn2Au has drawn
attention because it exhibits unique properties and its Neel temperature is
very high. Here, we report spin pumping and inverse spin Hall effect
investigations in Mn2Au and CoFeB bilayer system using ferromagnetic resonance.
We found large spin Hall angle {\theta}_SH = 0.22",1912.11522v2
2020-02-05,Correlated motion of particle-hole excitations across the renormalized spin-orbit gap in $\rm Sr_2 Ir O_4$,"The high-energy collective modes of particle-hole excitations across the
spin-orbit gap in $\rm Sr_2IrO_4$ are investigated using the transformed
Coulomb interaction terms in the pseudo-spin-orbital basis constituted by the
$J=1/2$ and $3/2$ states arising from spin-orbit coupling. With appropriate
interaction strengths and renormalized spin-orbit gap, these collective modes
yield two well-defined propagating spin-orbit exciton modes, with energy scale
and dispersion in excellent agreement with resonant inelastic X-ray scattering
(RIXS) measurements.",2002.02415v1
2023-11-27,Probing spin fractionalization with ESR-STM absolute magnetometry,"The emergence of effective $S=1/2$ spins at the edges of $S=1$ Haldane spin
chains is one of the simplest examples of fractionalization. Whereas there is
indirect evidence of this phenomenon, direct measurement of the magnetic moment
of an individual edge spin remains to be done. Here we show how scanning tunnel
microscopy electron-spin resonance (ESR-STM) can be used to map the stray field
created by the fractional $S=1/2$ edge spin and we propose efficient methods to
invert the Biot-Savart equation, obtaining the edge magnetization map. This
permits one to determine unambiguously the two outstanding emergent properties
of fractional degrees of freedom, namely, their fractional magnetic moment and
their localization length $\xi$.",2311.15720v1
2024-03-21,Efecto Hall de espin inverso en peliculas de Nb Mo y Bi por bombeo de espin,"The inverse spin Hall effect used for detection of spin currents was observed
by voltage measurements in bilayers of normal metal (NM)/ferromagnetic metal
(FM), using Nb, Mo and Bi as normal metal and Permalloy (Py,
Ni$_{81}$Fe$_{19}$) as ferromagnetic metal. The spin current was generated by
the spin pumping effect with ferromagnetic resonance. The samples were
deposited by dc magnetron sputtering at room temperature on Si (001)
substrates. The three bilayers of Nb/Py, Mo/Py and Bi/Py had a spin-orbit
coupling large enough to observe the voltage generation by spin Hall effect",2403.17976v1
2015-02-26,Unsteady self-sustained detonation waves in flake aluminum dust/air mixtures,"Self-sustained detonation waves in flake aluminum dust/air mixtures have been
studied in a tube of diameter 199 mm and length 32.4 m. A pressure sensor array
of 32 sensors mounted around certain circumferences of the tube was used to
measure the shape of the detonation front in the circumferential direction and
pressure histories of the detonation wave. A two-head spin detonation wave
front was observed for the aluminum dust/air mixtures, and the cellular
structure resulting from the spinning movement of the triple point was
analyzed. The variations in velocity and overpressure of the detonation wave
with propagation distance in a cell were studied. The interactions of waves in
triple-point configurations were analyzed and the flow-field parameters were
calculated. Three types of triple-point configuration exist in the wave front
of the detonation wave of an aluminum dust/air mixture. Both strong and weak
transverse waves exist in the unstable self-sustained detonation wave.",1503.01045v1
2009-11-01,Transmission resonances in above-barrier reflection of ultra-cold atoms by the Rosen-Morse potential,"Quantum above-barrier reflection of ultra-cold atoms by the Rosen-Morse
potential is analytically considered within the mean field Gross-Pitaevskii
approximation. Reformulating the problem of reflectionless transmission as a
quasi-linear eigenvalue problem for the potential depth, an approximation for
the specific height of the potential that supports reflectionless transmission
of the incoming matter wave is derived via modification of the
Rayleigh-Schroedinger time-independent perturbation theory. The approximation
provides highly accurate description of the resonance position for all the
resonance orders if the nonlinearity parameter is small compared with the
incoming particles chemical potential. Notably, the result for the first
transmission resonance turns out to be exact, i.e., the derived formula for the
resonant potential height gives the exact value of the first nonlinear
resonances position for all the allowed variation range of the involved
parameters, the nonlinearity parameter and chemical potential. This has been
shown by constructing the exact solution of the problem for the first
resonance. Furthermore, the presented approximation reveals that, in contrast
to the linear case, in the nonlinear case reflectionless transmission may occur
not only for potential wells but also for potential barriers with positive
potential height. It also shows that the nonlinear shift of the resonance
position from the position of the corresponding linear resonance is
approximately described as a linear function of the resonance order. Finally, a
compact (yet, highly accurate) analytic formula for the n-th order resonance
position is constructed via combination of analytical and numerical methods.",0911.0158v1
2012-06-01,Theoretical formalism for collective electromagnetic response of discrete metamaterial systems,"We develop a general formalism to describe the propagation of a near-resonant
electromagnetic field in a medium composed of magnetodielectric resonators. As
the size and the spatial separation of nanofabricated resonators in a
metamaterial array is frequently less than the wavelength, we describe them as
discrete scatterers, supporting a single mode of current oscillation
represented by a single dynamic variable. We derive a Lagrangian and
Hamiltonian formalism for the coupled electromagnetic fields and oscillating
currents in the length gauge, obtained by the Power-Zienau-Woolley
transformation. The response of each resonator to electromagnetic field is then
described by polarization and magnetization densities that, to the lowest order
in a multipole expansion, generate electric and magnetic dipole excitations. We
derive a closed set of equations for the coherently scattered field and normal
mode amplitudes of current oscillations of each resonator both within the
rotating wave approximation, in which case the radiative decay rate is much
smaller than the resonance frequency, and without such an assumption. The set
of equations includes the radiative couplings between a discrete set of
resonators mediated by the electromagnetic field, fully incorporating recurrent
scattering processes to all orders. By considering an example of a
two-dimensional split ring resonator metamaterial array, we show that the
system responds cooperatively to near-resonant field, exhibiting collective
eigenmodes, resonance frequencies, and radiative linewidths that result from
strong radiative interactions between closely-spaced resonators.",1206.0204v2
2018-08-30,Large scale changes in overtone resonances and resonant peak burning of HBAR with mass loading and its potential for applications,"This report presents the realization and characterization of a robust
composite resonator i.e. high overtone bulk acoustic wave resonator (HBAR) and
the changes happening to the resonance peaks once it undergoes mass loading
which has got the potential for application in material characterization,
communication system and sensing. Mass loading effect on a HBAR based on
BaxSr1-xTiO3 (BST) have been demonstrated by coating photoresist of various
thicknesses and characterization of resonance modes present in the frequency
spectrum of the resonator. Upon investigation, HBAR proves to be one of the
most promising and robust systems for gravimetric sensing. Burning effect in
the resonances occurs and it shifts significantly according to the amount of
mass loaded (increasing thickness of the photoresist coated) on the resonator
system. Some of the most important parameters like effective coupling
coefficient, spacing of parallel resonance frequency (SPRF) and quality factor
of the resonator and its numerous modes have been investigated meticulously.",1808.10118v2
2020-11-30,Resonances for Schrödinger operators on infinite cylinders and other products,"We study the resonances of Schr\""odinger operators on the infinite product
$X=\mathbb{R}^d\times \mathbb{S}^1$, where $d$ is odd, $\mathbb{S}^1$ is the
unit circle, and the potential $V\in L^\infty_c(X)$. This paper shows that at
high energy, resonances of the Schr\""odinger operator $-\Delta +V$ on
$X=\mathbb{R}^d\times \mathbb{S}^1$ which are near the continuous spectrum are
approximated by the resonances of $-\Delta +V_0$ on $X$, where the potential
$V_0$ given by averaging $V$ over the unit circle. These resonances are, in
turn, given in terms of the resonances of a Schr\""odinger operator on
$\mathbb{R}^d$ which lie in a bounded set. If the potential is smooth, we
obtain improved localization of the resonances, particularly in the case of
simple, rank one poles of the corresponding scattering resolvent on
$\mathbb{R}^d$. In that case, we obtain the leading order correction for the
location of the corresponding high energy resonances. In addition to direct
results about the location of resonances, we show that at high energies away
from the resonances, the resolvent of the model operator $-\Delta+V_0$ on $X$
approximates that of $-\Delta+V$ on $X$. If $d=1$, in certain cases this
implies the existence of an asymptotic expansion of solutions of the wave
equation. Again for the special case of $d=1$, we obtain a resonant rigidity
type result for the zero potential among all real-valued potentials.",2011.14513v2
2009-02-17,Fano resonances in nanoscale structures,"Nowadays nanotechnology allows to scale-down various important devices
(sensors, chips, fibres, etc), and, thus, opens up new horizon for their
applications. Nevertheless, the efficiency most of them is still based on the
fundamental physical phenomena, such as resonances. Thus, the understanding of
the resonance phenomena will be beneficial. One of the well-known examples is
the resonant enhancement of the transmission known as Breit-Wigner resonances,
which can be described by a Lorentzian function. But, in many physical systems
the scattering of waves involves propagation along different paths, and, as a
consequence, results in interference phenomena, where constructive interference
corresponds to resonant enhancement and destructive interference to resonant
suppression of the transmission. Recently, a variety of experimental and
theoretical work has revealed such patterns in different branches of physics.
The purpose of this Review is to demonstrate that this kind of resonant
scattering is related to the Fano resonances, known from atomic physics. One of
the main features of the Fano resonances is the asymmetric profile. The
asymmetry comes from the close coexistence of resonant transmission and
resonant reflection. Fano successfully explained such a phenomenon in his
seminal paper in 1961 in terms of interaction of a discrete (localized) state
with a continuum of propagation modes. It allows to describe both resonant
enhancement and resonant suppression in a unified manner. All of these
properties can be demonstrated in the frame of a very simple model, which will
be used throughout the Review to show that resonant reflections observed in
different complex systems are indeed closely related to the Fano resonances.",0902.3014v4
1995-12-13,Model for Resonance Enhancement of P- and T-noninvariant Effects in Neutron Reactions,"We consider a simplified model for resonant neutron-nucleus interaction with
coupled channels. An analytical solution is given for two coupled channels and
arbitrary neutron orbital momentum. A case of a week channel coupling,
corresponding to narrow Breit-Wigner resonance, is analyzed in details. As far
as the total width of a resonance coincides with the neutron width, the model
is directly appropriate only for light nuclei. We study a mixing of two narrow
s- and p-wave resonances by P- and P-,T-noninvariant potentials in the first
order of perturbation theory. As an example a close-lying pair of s- and p-wave
resonances of the $^{35}$Cl nucleus is considered. The favorable possibilities
are shown to exist on thick targets for measurements beyond the resonance
widths. In particular, an interference minimum near s-wave resonance is of
interest for P-odd neutron spin rotation on light spinless nuclei.",9512020v2
2010-12-10,Quantum pumping in graphene nanoribbons at resonant transmission,"Adiabatic quantum charge pumping in graphene nanoribbon double barrier
structures with armchair and zigzag edges in the resonant transmission regime
is analyzed. Using recursive Green's function method we numerically calculate
the pumped charge for pumping contours encircling a resonance. We find that for
armchair ribbons the whole resonance line contributes to the pumping of a
single electron (ignoring double spin degeneracy) per cycle through the device.
The case of zigzag ribbons is more interesting due to zero-conductance
resonances. These resonances separate the whole resonance line into several
parts, each of which corresponds to the pumping of a single electron through
the device. Moreover, in contrast to armchair ribbons, one electron can be
pumped from the left lead to the right one or backwards. The current direction
depends on the particular part of the resonance line encircled by the pumping
contour.",1012.2221v1
2016-08-22,Metallic coplanar resonators optimized for low-temperature measurements,"Metallic coplanar microwave resonators are widely employed at room
temperature, but their low-temperature performance has received little
attention so far. We characterize compact copper coplanar resonators with
multiple modes from 2.5 to 20 GHz at temperatures as low as 5 K. We investigate
the influence of center conductor width (20 to 100 {\mu}m) and coupling gap
size (10 to 50 {\mu}m), and we observe a strong increase of quality factor (Q)
for wider center conductors, reaching values up to 470. The magnetic-field
dependence of the resonators is weak, with a maximum change in Q of 3.5% for an
applied field of 7 T. This makes these metallic resonators well suitable for
magnetic resonance studies, as we document with electron spin resonance (ESR)
measurements at multiple resonance frequencies.",1608.06122v1
2018-09-28,Towards the Minimal Spectrum of Excited Baryons,"In the light baryon sector resonances can be broad and overlapping and are in
most cases not directly visible in the cross section data. Automatized model
selection techniques that introduce penalties for resonances can be used to
determine the minimally needed set of resonances to describe the data. Several
possible penalization schemes are compared. As an application we perform a
blindfold identification of hyperon resonances in the $\bar{K} N \to K \Xi$
reaction based on the Least Absolute Shrinkage and Selection Operator (LASSO)
in combination with the Bayesian Information Criterion (BIC). We find ten
resonances --- out of the 21 above-threshold hyperon resonances with spin $J\le
7/2$ listed by the Particle Data Group. In traditional analyses, it is
practically impossible to test the relevance of all resonances and their
combinations that may potentially contribute to the reaction. By contrast, the
present method proves capable of determining the relevant resonances among a
large pool of candidates.",1810.00075v2
2019-08-30,A case study about the mass exclusion limits for the BSM vector resonances with the direct couplings to the third quark generation,"The upper bounds that the LHC measurements searching for heavy resonances
beyond the Standard model set on the resonance production cross sections are
not universal. They depend on various characteristics of the resonance under
consideration, like its mass, spin, and its interaction pattern. Their validity
are also limited by the assumptions and approximations applied to their
calculations. The bounds are typically used to derive the mass exclusion limits
for the new resonances. In our work, we address some of the issues that emerge
when deriving the mass exclusion limits for the strongly coupled composite
$SU(2)_{L+R}$ vector resonance triplet which would interact directly to the
third quark generation only. We investigate the restrictions on the
applicability of the generally used limit-obtaining procedure to this
particular type of vector resonances. We demonstrate that, in this case, it is
necessary to consider the bottom quark partonic contents of the proton.
Eventually, we find the mass exclusion limits for this resonance triplet for
some representative subsets of the parameter space.",1908.11619v2
2023-09-28,Quantum Resonance viewed as Weak Measurement,"Quantum resonance, i.e., amplification in transition probability available
under certain conditions, offers a powerful means for determining fundamental
quantities in physics, including the time duration of the second adopted in the
SI units and neutron's electric dipole moment which is directly linked to CP
violation. We revisit two of the typical examples, the Rabi resonance and the
Ramsey resonance, and show that both of these represent the weak value
amplification and that near the resonance points they share exactly the same
behavior of transition probabilities except for the measurement strength whose
difference leads to the known advantage of the Ramsey resonance in the
sensitivity. Conversely, as a by-product of the relationship, we may measure
the weak value through quantum resonance. In fact, we argue that previous
measurements of neutron electric dipole moment based on the Ramsey resonance
have potentially determined the weak value of neutron's spin with much higher
precision than the conventional weak value measurement.",2309.16281v2
2022-03-03,Spin Hall effects and the localization of massless spinning particles,"The spin Hall effects of light represent a diverse class of
polarization-dependent physical phenomena involving the dynamics of
electromagnetic wave packets. In a medium with an inhomogeneous refractive
index, wave packets can be effectively described by massless spinning particles
following polarization-dependent trajectories. Similarly, in curved spacetime
the gravitational spin Hall effect of light is represented by
polarization-dependent deviations from null geodesics. In this paper, we
analyze the equations of motion describing the gravitational spin Hall effect
of light. We show that these equations are a special case of the
Mathisson-Papapetrou equations for spinning objects in general relativity. This
allows us to use several known results for the Mathisson-Papapetrou equations,
and apply them to the study of electromagnetic wave packets. We derive
conservation laws, we discuss the limits of validity of the spin Hall
equations, and we study how the energy centroids of wave packets, effectively
described as massless spinning particles, depend on the external choice of a
timelike vector field, representing a family of observers. In flat spacetime,
the relativistic Hall effect and the Wigner(-Souriau) translations are
recovered, while our equations also provide a generalization of these effects
in arbitrary spacetimes. We construct a large class of wave packets that can be
described by the spin Hall equations, but also find its limits by giving
examples of wave packets which are more general and are not described by the
spin Hall equations. Lastly, we examine the assumption that electromagnetic
wave packets are massless. While this is approximately true in many contexts,
it is not exact. We show that failing to carefully account for the limitations
of the massless approximation results in the appearance of unphysical centroids
which are nowhere near the wave packet itself.",2203.01753v2
2022-02-24,Coherence of ion cyclotron resonance for damping ion cyclotron waves in space plasmas,"Ion cyclotron resonance is one of the fundamental energy conversion processes
through field-particle interaction in collisionless plasmas. However, the key
evidence for ion cyclotron resonance (i.e., the coherence between
electromagnetic fields and the ion phase space density) and the resulting
damping of ion cyclotron waves (ICWs) has not yet been directly observed.
Investigating the high-quality measurements of space plasmas by the
Magnetospheric Multiscale (MMS) satellites, we find that both the wave
electromagnetic field vectors and the bulk velocity of the disturbed ion
velocity distribution rotate around the background magnetic field. Moreover, we
find that the absolute gyro-phase angle difference between the center of the
fluctuations in the ion velocity distribution functions and the wave electric
field vectors falls in the range of (0, 90) degrees, consistent with the
ongoing energy conversion from wave-fields to particles. By invoking plasma
kinetic theory, we demonstrate that the field-particle correlation for the
damping ion cyclotron waves in our theoretical model matches well with our
observations. Furthermore, the wave electric field vectors ($\delta
\mathbf{E'}_{\mathrm {wave,\perp}}$), the ion current density ($\delta
\mathbf{J}_\mathrm {i,\perp}$) and the energy transfer rate ($\delta
\mathbf{J}_\mathrm {i,\perp}\cdot \delta \mathbf{E'}_{\mathrm {wave,\perp}}$)
exhibit quasi-periodic oscillations, and the integrated work done by the
electromagnetic field on the ions are positive, indicates that ions are mainly
energized by the perpendicular component of the electric field via cyclotron
resonance. Therefore, our combined analysis of MMS observations and kinetic
theory provides direct, thorough, and comprehensive evidence for ICW damping in
space plasmas.",2202.11967v1
2005-09-04,Grazing-angle scattering of electromagnetic waves in gratings with varying mean parameters: grating eigenmodes,"A highly unusual pattern of strong multiple resonances for bulk
electromagnetic waves is predicted and analysed numerically in thick periodic
holographic gratings in a slab with the mean permittivity that is larger than
that of the surrounding media. This pattern is shown to exist in the geometry
of grazing-angle scattering (GAS), that is when the scattered wave (+1
diffracted order) in the slab propagates almost parallel to the slab (grating)
boundaries. The predicted resonances are demonstrated to be unrelated to
resonant generation of the conventional guided modes of the slab. Their
physical explanation is associated with resonant generation of a completely new
type of eigenmodes in a thick slab with a periodic grating. These new slab
eigenmodes are generically related to the grating; they do not exist if the
grating amplitude is zero. The field structure of these eigenmodes and their
dependence on structural and wave parameters is analysed. The results are
extended to the case of GAS of guided modes in a slab with a periodic groove
array of small corrugation amplitude and small variations in the mean thickness
of the slab at the array boundaries.",0509029v1
2007-12-01,Feshbach shape resonance for high Tc superconductivity in superlattices of nanotubes,"The case of a Feshbach shape resonance in the pairing mechanism for high T c
superconductivity in a crystalline lattice of doped metallic nanotubes is
described. The superlattice of doped metallic nanotubes provides a
superconductor with a strongly asymmetric gap. The disparity and different
spatial locations of the wave functions of electrons in different subbands at
the Fermi level should suppress the single electron impurity interband
scattering giving multiband superconductivity in the clean limit. The Feshbach
resonances will arise from the component single-particle wave functions out of
which the electron pair wave function is constructed: pairs of wave functions
which are time inverse of each other. The Feshbach shape resonance increases
the critical temperature by tuning the chemical potential at the Lifshitz
electronic topological transition (ETT) where the Fermi surface of one of the
bands changes from the one dimensional (1D) to the two dimensional (2D)
topology (1D/2D ETT).",0712.0061v1
2010-03-30,Change of the resonant electron orbit from trapped orbit to passing orbit in fast wave current drive,"In fast wave current drive, the resonant electron is accelerated by fast wave
in the direction parallel to the static magnetic field, and the parallel
velocity will be increased. The trajectories of the trapped resonant electrons
are calculated with a computer code in which fast wave-induced diffusion in
velocity space is accounted for by a quasi-linear operator. The simulation
results show that the orbit of trapped resonant electron will change from a
trapped orbit to a passing orbit in some cases. We obtain the transition
conditions, and if they are satisfied the trapped orbit will become a passing
orbit. The transition from trapped orbit to passing orbit implies that the
effect of trapped electrons on current drive will be reduced and the current
drive efficiency will be improved.",1003.5719v1
2010-12-30,A lattice model for resonance in open periodic waveguides,"We present a discrete model of resonant scattering of waves by an open
periodic waveguide. The model elucidates a phenomenon common in
electromagnetics, in which the interaction of plane waves with embedded guided
modes of the waveguide causes sharp transmission anomalies and field
amplification. The ambient space is modeled by a planar lattice and the
waveguide by a linear periodic lattice coupled to the planar one along a line.
We show the existence of standing and traveling guided modes and analyze a
tangent bifurcation, in which resonance is initiated at a critical coupling
strength where a guided mode appears, beginning with a single standing wave and
splitting into a pair of waves traveling in opposing directions. Complex
perturbation analysis of the scattering problem in the complex frequency and
wavenumber domain reveals the complex structure of the transmission coefficient
at resonance.",1101.0170v1
2013-01-02,Tidal Instability and Superhump by a Wave-Wave Resonant Model,"On a disk deformed to a non-axisymmetric form, a set of oscillations can be
excited by their resonant interaction through the disk deformation (Kato et al.
2011). This resonant instability process has been proposed to suggest a
possible cause of the high-frequency quasi-periodic oscillations (HF QPOs)
observed in black-hole low-mass X-ray binaries. In the present paper, we
examine whether the above-mentioned wave-wave resonant process can describe the
tidal instability and superhump in dwarf novae. The results show that the
process seems to well describe the observations. If this process is really the
cause of the tidal instability and superhump, a two-armed oscillation with high
frequency roughly on the magnitude of three times the orbital frequency is
present on disks, although its expected amplitude may be small.",1301.0232v1
2013-11-08,Theory of a Directive Optical Leaky Wave Antenna Integrated into a Resonator and Enhancement of Radiation Control,"We provide for the first time the detailed study of the radiation performance
of an optical leaky wave antenna (OLWA) integrated into a Fabry-P\'erot
resonator. We show that the radiation pattern can be expressed as the one
generated by the interference of two leaky waves counter-propagating in the
resonator leading to a design procedure for achieving optimized broadside
radiation, i.e., normal to the waveguide axis. We thus report a realizable
implementation of the OLWA made of semiconductor and dielectric regions. The
theoretical modeling is supported by full-wave simulation results, which are
found to be in good agreement. We aim to control the radiation intensity in the
broadside direction via excess carrier generation in the semiconductor regions.
We show that the presence of the resonator can provide an effective way of
enhancing the radiation level modulation, which reaches values as high as 13.5
dB, paving the way for novel promising control capabilities that might allow
the generation of very fast optical switches, as an example.",1311.1858v1
2016-06-02,Parametrically tunable soliton-induced resonant radiation by three-wave mixing,"We show that a temporal soliton can induce resonant radiation by three-wave
mixing nonlinearities. This constitutes a new class of resonant radiation whose
spectral positions are parametrically tunable. The experimental verification is
done in a periodically poled lithium niobate crystal, where a femtosecond
near-IR soliton is excited and resonant radiation waves are observed exactly at
the calculated soliton phase-matching wavelengths via the sum- and
difference-frequency generation nonlinearities. This extends the supercontinuum
bandwidth well into the mid-IR to span 550-5000 nm and the mid-IR edge is
parametrically tunable over 1000 nm by changing the three-wave mixing
phase-matching condition. The results are important for bright and broadband
supercontinuum generation and for frequency comb generation in quadratic
nonlinear microresonators.",1606.00572v4
2016-06-06,A Resonant Mode for Gravitational Wave Detectors based on Atom Interferometry,"We describe an atom interferometric gravitational wave detector design that
can operate in a resonant mode for increased sensitivity. By oscillating the
positions of the atomic wavepackets, this resonant detection mode allows for
coherently enhanced, narrow-band sensitivity at target frequencies. The
proposed detector is flexible and can be rapidly switched between broadband and
narrow-band detection modes. For instance, a binary discovered in broadband
mode can subsequently be studied further as the inspiral evolves by using a
tailored narrow-band detector response. In addition to functioning like a
lock-in amplifier for astrophysical events, the enhanced sensitivity of the
resonant approach also opens up the possibility of searching for important
cosmological signals, including the stochastic gravitational wave background
produced by inflation. We give an example of detector parameters which would
allow detection of inflationary gravitational waves down to $\Omega_\text{GW}
\sim 10^{-14}$ for a two satellite space-based detector.",1606.01860v2
2019-11-26,Mapping for nonlinear electron interaction with whistler-mode waves,"The resonant interaction of relativistic electrons and whistler waves is an
important mechanism of electron acceleration and scattering in the Earth
radiation belts and other space plasma systems. For low amplitude waves, such
an interaction is well described by the quasi-linear diffusion theory, whereas
nonlinear resonant effects induced by high-amplitude waves are mostly
investigated (analytically and numerically) using the test particle approach.
In this paper, we develop a mapping technique for the description of this
nonlinear resonant interaction. Using the Hamiltonian theory for resonant
systems, we derive the main characteristics of electron transport in the phase
space and combine these characteristics to construct the map. This map can be
considered as a generalization of the classical Chirikov map for systems with
nondiffusive particle transport and allows us to model the long-term evolution
of the electron distribution function.",1911.11459v1
2018-02-14,Pathway towards programmable wave anisotropy in cellular metamaterials,"In this work, we provide a proof-of-concept experimental demonstration of the
wave control capabilities of cellular metamaterials endowed with populations of
tunable electromechanical resonators. Each independently tunable resonator
comprises a piezoelectric patch and a resistor-inductor shunt, and its resonant
frequency can be seamlessly re-programmed without interfering with the cellular
structure's default properties. We show that, by strategically placing the
resonators in the lattice domain and by deliberately activating only selected
subsets of them, chosen to conform to the directional features of the beamed
wave response, it is possible to override the inherent wave anisotropy of the
cellular medium. The outcome is the establishment of tunable spatial patterns
of energy distillation resulting in a non-symmetric correction of the
wavefields.",1802.04959v1
2019-06-25,Topologically protected edge modes in one-dimensional chains of subwavelength resonators,"The goal of this paper is to advance the development of wave-guiding
subwavelength crystals by developing designs whose properties are stable with
respect to imperfections in their construction. In particular, we make use of a
locally resonant subwavelength structure, composed of a chain of high-contrast
resonators, to trap waves at deep subwavelength scales. We first study an
infinite chain of subwavelength resonator dimers and define topological
quantities that capture the structure's wave transmission properties. Using
this for guidance, we design a finite crystal that is shown to have wave
localization properties, at subwavelength scales, that are robust with respect
to random imperfections.",1906.10688v2
2020-04-20,Resonant whistler-electron interactions: MMS observations vs. test-particle simulation,"Simultaneous observation of characteristic 3-dimensional (3D) signatures in
the electron velocity distribution function (VDF) and intense
quasi-monochromatic waves by the Magnetospheric Multiscale (MMS) spacecraft in
the terrestrial magnetosheath are investigated. The intense wave packets are
characterised and modeled analytically as quasi-parallel circularly-polarized
whistler waves and applied to a test-particle simulation in view of gaining
insight into the signature of the wave-particle resonances in velocity space.
Both the Landau and the cyclotron resonances were evidenced in the
test-particle simulations. The location and general shape of the test-particle
signatures do account for the observations, but the finer details, such as the
symmetry of the observed signatures are not matched, indicating either the
limits of the test-particle approach, or a more fundamental physical mechanism
not yet grasped. Finally, it is shown that the energisation of the electrons in
this precise resonance case cannot be diagnosed using the moments of the
distribution function, as done with the classical ${\bf E}.{\bf J}$
""dissipation"" estimate.",2004.09130v1
2020-04-21,Fabry-Perot resonance of water waves,"We show that significant water wave amplification is obtained in a water
resonator consisting of two spatially separated patches of small-amplitude
sinusoidal corrugations on an otherwise flat seabed. The corrugations reflect
the incident waves according to the so-called Bragg reflection mechanism, and
the distance between the two sets controls whether the trapped reflected waves
experience constructive or destructive interference within the resonator. The
resulting amplification or suppression is enhanced with increasing number of
ripples, and is most effective for specific resonator lengths and at the Bragg
frequency, which is determined by the corrugation period. Our analysis draws on
the analogous mechanism that occurs between two partially reflecting mirrors in
optics, a phenomenon named after its discoverers Charles Fabry and Alfred
Perot.",2004.09967v1
2019-03-14,Quantum expander for gravitational-wave observatories,"Quantum uncertainty of laser light limits the sensitivity of
gravitational-wave observatories. In the past 30 years, techniques for
squeezing the quantum uncertainty as well as for enhancing the
gravitational-wave signal with optical resonators were invented. Resonators,
however, have finite linewidths; and the high signal frequencies that are
produced during the scientifically highly interesting ring-down of
astrophysical compact-binary mergers cannot be resolved today. Here, we propose
an optical approach for expanding the detection bandwidth. It uses quantum
uncertainty squeezing inside one of the optical resonators, compensating for
finite resonators' linewidths while maintaining the low-frequency sensitivity
unchanged. Introducing the quantum expander for boosting the sensitivity of
future gravitational-wave detectors, we envision it to become a new tool in
other cavity-enhanced metrological experiments.",1903.05930v1
2020-03-24,Imaging the onset of the resonance regime in low-energy NO-He collisions,"At low energies, the quantum wave-like nature of molecular interactions
result in unique scattering behavior, ranging from the universal Wigner laws
near zero Kelvin to the occurrence of scattering resonances at higher energies.
It has proven challenging to experimentally probe the individual waves
underlying these phenomena. We report measurements of state-to-state integral
and differential cross sections for inelastic NO-He collisions in the 0.2 - 8.5
cm$^{-1}$ range with 0.02 cm$^{-1}$ resolution. We study the onset of the
resonance regime by probing the lowest-lying resonance dominated by s and p
waves only. The highly structured differential cross sections directly reflect
the increasing number of contributing waves as the energy is increased. A new
NO-He potential calculated at the CCSDT(Q) level was required to reproduce our
measurements.",2003.10742v1
2016-11-02,Wave emission and absorption at spectral singularities,"We studied the critical dynamics of spectral singularities. The system
investigated is a coupled resonator array with a side-coupled loss (gain)
resonator. For a gain resonator, the system acts as a wave emitter at spectral
singularities. The reflection probability increased linearly over time. The
rate of increase is proportional to the width of the incident wave packet,
which served as the spectral singularity observer in the experiment. For a
lossy resonator, the system acts as a wave absorber. The emission and
absorption states at spectral singularities coalesce in a finite parity-time
(PT ) symmetric system that combined by the gain and loss structures cut from
corrresponding scattering systems at spectral singularities; in this case, the
PT -symmetric system is at an exceptional point with a 2 * 2 Jordan block. The
dynamics of the PT -symmetric system exhibit the characteristic of exceptional
points and spectral singularities.",1611.00572v1
2020-05-10,"Experimental investigation of amplification, via a mechanical delay-line, in a rainbow-based metasurface for energy harvesting","We demonstrate that a rainbow-based metasurface, created by a graded array of
resonant rods attached to an elastic beam, operates as a mechanical delay-line
by slowing down surface elastic waves to take advantage of wave interaction
with resonance. Experiments demonstrate that the rainbow effect reduces the
amplitude of the propagating wave in the host structure. At the same time it
dramatically increases both the period of interaction between the waves and the
resonators, and the wavefield amplitude in the rod endowed with the harvester.
Increased energy is thus fed into the resonators over time, we show the
enhanced energy harvesting capabilities of this system.",2005.04792v1
2022-04-12,Free-space-coupled wavelength-scale disk resonators,"Optical microresonators with low quality factor ($Q$) can be efficiently
excited by and scatter freely propagating optical waves, but those with high
$Q$ typically cannot. Here, we present a universal model for resonators
interacting with freely propagating waves and show that the stored energy of a
resonator excited by a plane wave is proportional to the product of its $Q$ and
directivity. Guided by this result, we devise a microdisk with periodic
protrusions in its circumference that couples efficiently to normally incident
plane waves. We experimentally demonstrate several microdisk designs, including
one with a radius of $0.75{\lambda_0}$ and $Q$ of 15,000. Our observation of
thermally-induced bistability in this resonator at input powers as low as 0.7
mW confirms strong excitation. Their small footprints and mode volumes and the
simplicity of their excitation and fabrication make wavelength-scale,
free-space-coupled microdisks attractive for sensing, enhancing emission and
nonlinearity, and as micro-laser cavities.",2204.05816v1
2022-06-20,A modified Bragg's law of Class I Bragg resonances of linear long waves excited by an array of artificial bars,"Based on the band theory of Bloch waves, a modified Bragg's law is
established for Class I Bragg resonances when linear long waves are reflected
by a finite periodic array of artificial bars, including rectangular,
parabolic, rectified cosinoidal, isosceles trapezoidal, and isosceles
triangular bars. The modified Bragg's law is described by a function of several
parameters such as the bar shape, dimensionless bar height with respect to the
global water depth, and dimensionless bar width with respect to the incident
wavelength. It is found that Bragg's law is just a limiting case of the
modified Bragg's law as the bar height or width approaches zero. This fact
tells us that the Bragg's law that accurately describes Bragg resonances in
X-ray crystallography cannot be simply applied to Bragg resonances of linear
long water waves excited by any finite periodic array of artificial bars,
because the height and width of any artificial bar cannot be zero. Based on the
modified Bragg's law, the phenomenon of phase downshifting can be well
explained and accurately predicted. It is revealed that the phase downshifting
becomes more significant with increasing the cross-sectional area of artificial
bars.",2206.13243v1
2022-08-24,Ultrasonic wave transport in concentrated disordered resonant emulsions,"We show how resonant (near-field) coupling affects wave transport in
disordered media through ultrasonic experiments in concentrated suspensions.
The samples consist of resonant emulsions in which oil droplets are suspended
in a liquid gel. By varying the droplet concentration, the limits of the
Independent Scattering Approximation are experimentally demonstrated. For the
most concentrated samples, the proximity of resonant scatterers induces a
renormalization of the surrounding medium, leading to a reducing of scattering
strength. We point out an optimal volume fraction of oil droplets for which
non-diffusive wave transport is experimentally demonstrated. Our demonstration
of maximum scattering at an intermediate droplet concentration is very relevant
for designing materials for the study of wave transport phenomena such as
Anderson Localization.",2208.11684v1
2009-05-14,Modulational instability of Rossby and drift waves and generation of zonal jets,"We study the modulational instability of geophysical Rossby and plasma drift
waves within the Charney-Hasegawa-Mima (CHM) model both theoretically, using
truncated (four-mode and three-mode) models, and numerically, using direct
simulations of CHM equation in the Fourier space. The linear theory predicts
instability for any amplitude of the primary wave. For strong primary waves the
most unstable modes are perpendicular to the primary wave, which correspond to
generation of a zonal flow if the primary wave is purely meridional. For weaker
waves, the maximum growth occurs for off-zonal inclined modulations. For very
weak primary waves the unstable waves are close to being in three-wave
resonance with the primary wave. The nonlinear theory predicts that the zonal
flows generated by the linear instability experience pinching into narrow zonal
jets. Our numerical simulations confirm the theoretical predictions of the
linear theory as well as of the nonlinear pinching. We find that, for strong
primary waves, these narrow zonal jets further roll up into Karman-like vortex
streets. On the other hand, for weak primary waves, the growth of the unstable
mode reverses and the system oscillates between a dominant jet and a dominate
primary wave. The 2D vortex streets appear to be more stable than purely 1D
zonal jets, and their zonal-averaged speed can reach amplitudes much stronger
than is allowed by the Rayleigh-Kuo instability criterion for the 1D case. We
find that the truncation models work well for both the linear stage and and
often even for the medium-term nonlinear behavior. In the long term, the system
transitions to turbulence helped by the vortex-pairing instability (for strong
waves) and by the resonant wave-wave interactions (for weak waves).",0905.2243v1
2004-09-26,The improvement wave equations of relativistic and non-relativistic quantum mechanics,"In this work, we follow the idea of the De Broglie's matter waves and the
analogous method that Schr\""{o}dinger founded wave equation, but we apply the
more essential Hamilton principle instead of the minimum action principle of
Jacobi which was used in setting up Schr\""{o}dinger wave equation. Thus, we
obtain a novel non-relativistic wave equation which is different from the
Schr\""{o}dinger equation, and relativistic wave equation including free and
non-free particle. In addition, we get the spin 1/2 particle wave equation in
potential field.",0409176v1
2009-03-09,An EOM-assisted wave-vector-resolving Brillouin light scattering setup,"Brillouin light scattering spectroscopy is a powerful technique which
incorporates several extensions such as space-, time-, phase- and wave-vector
resolution.
  Here, we report on the improvement of the wave-vector resolution by including
an electro-optical modulator. This provides a reference to calibrate the
position of the diaphragm hole which is used for wave-vector selection. The
accuracy of this calibration is only limited by the accuracy of the wave-vector
measurement itself. To demonstrate the validity of the approach the wave
vectors of dipole-dominated spin waves excited by a microstrip antenna were
measured.",0903.1536v1
2014-11-04,Chaotic Dynamics of Stellar Spin Driven by Planets Undergoing Lidov-Kozai Oscillations: Resonances and Origin of Chaos,"Many exoplanetary systems containing hot Jupiters are found to possess
significant misalignment between the spin axis of the host star and the
planet's orbital angular momentum axis. A possible channel for producing such
misaligned hot Jupiters involves Lidov-Kozai oscillations of the planet's
orbital eccentricity and inclination driven by a distant binary companion. In a
recent work (Storch, Anderson & Lai 2014), we have shown that a proto-hot
Jupiter undergoing Lidov-Kozai oscillations can induce complex, and often
chaotic, evolution of the spin axis of its host star. Here we explore the
origin of the chaotic spin behavior and its various features in an idealized
non-dissipative system where the secular oscillations of the planet's orbit are
strictly periodic. Using Hamiltonian perturbation theory, we identify a set of
secular spin-orbit resonances in the system, and show that overlaps of these
resonances are responsible for the onset of wide-spread chaos in the evolution
of stellar spin axis. The degree of chaos in the system depends on the
adiabaticity parameter $\epsilon$, proportional to the ratio of the Lidov-Kozai
nodal precession rate and the stellar spin precession rate, and thus depends on
the planet mass, semi-major axis and the stellar rotation rate. For systems
with zero initial spin-orbit misalignment, our theory explains the occurrence
(as a function of $\epsilon$) of ""periodic islands"" in the middle of a ""chaotic
ocean"" of spin evolution, and the occurrence of restricted chaos in middle of
regular/periodic spin evolution. Finally, we discuss a novel ""adiabatic
resonance advection"" phenomenon, in which the spin-orbit misalignment, trapped
in a resonance, gradually evolves as the adiabaticity parameter slowly changes.
This phenomenon can occur for certain parameter regimes when tidal decay of the
planetary orbit is included.",1411.0739v1
2003-04-11,Spin Manipulation of Free 2-Dimensional Electrons in Si/SiGe Quantum Wells,"An important requirement for a physical embodiment of a quantum computer is
that arbitrary single-qubit operations can be performed. In the case of
spin-qubits, this means that arbitrary spin rotations must be possible. Here we
demonstrate spin rotations of an ensemble of free 2-dimensional electrons
confined to a silicon quantum well embedded in a silicon-germanium alloy host.
The spins are manipulated by resonant microwave pulses and an applied magnetic
field in a pulsed electron paramagnetic resonance spectrometer. From the pulsed
measurements we deduce a spin coherence time in this system of about 3
microsec, allowing at least 100 elementary operations before decoherence
destroys the spin state. These measurements represent an important step towards
the realization of quantum computation using electron spins in semiconductors,
but at the same time establish some constraints on the design of such a system.",0304284v1
2003-04-29,Spin and energy transfer in nanocrystals without transport of charge,"We describe a mechanism of spin transfer between individual quantum dots that
does not require tunneling. Incident circularly-polarized photons create
inter-band excitons with non-zero electron spin in the first quantum dot. When
the quantum-dot pair is properly designed, this excitation can be transferred
to the neighboring dot via the Coulomb interaction with either {\it
conservation} or {\it flipping} of the electron spin. The second dot can
radiate circularly-polarized photons at lower energy. Selection rules for spin
transfer are determined by the resonant conditions and by the strong spin-orbit
interaction in the valence band of nanocrystals. Coulomb-induced energy and
spin transfer in pairs and chains of dots can become very efficient under
resonant conditions. The electron can preserve its spin orientation even in
randomly-oriented nanocrystals.",0304663v2
2006-02-05,Nuclear Spin Noise and STM Noise Spectroscopy,"We consider fluctuations of the electronic spin due to coupling to nuclear
spin. Noise spectroscopy of an electronic spin can be revealed in the Scanning
Tunnelling Microscope (STM). We argue that the noise spectroscopy of electronic
spin can reveal the nuclear spin dynamics due to hyperfine coupling. Tunnelling
current develops satellites of the main lines at Larmor frequency and at zero
frequency due to hyperfine coupling. We also address the role of the rf field
that is at or near the resonance with the nuclear hyperfine field. This
approach is similar to Electron Nuclear Double Resonance (ENDOR), in that is
allows one to detect nuclear spin dynamics indirectly through its effect on
electronic spin.",0602113v1
2007-03-01,Driven dissipative dynamics of spins in quantum dots,"We have studied the dissipative dynamics of a driven electronic spin trapped
in a quantum dot. We consider the dissipative mechanism as due to the indirect
coupling of the electronic spin to acoustic phonons via the
spin-orbit/electron-phonon couplings. Using an effective spectral function of
the dissipative phonon bath, we evaluated the expectation values of the spin
components through the Bloch-Redfield theory. We show that due to a sharp bath
resonance present in the effective spectral function, with typical energy much
smaller than the electronic confinement energy, the dissipative spin has a rich
dynamical behavior that helps us to determine some features of the spin-bath
coupling. We also quantify the effects produced by the sharp bath resonance,
and thus indicate the best regimes of operation in order to achieve the longest
relaxation times for the spin.",0703009v1
2001-08-06,Quantum Measurement of a Single Spin using Magnetic Resonance Force Microscopy,"Single-spin detection is one of the important challenges facing the
development of several new technologies, e.g. single-spin transistors and
solid-state quantum computation. Magnetic resonance force microscopy with a
cyclic adiabatic inversion, which utilizes a cantilever oscillations driven by
a single spin, is a promising technique to solve this problem. We have studied
the quantum dynamics of a single spin interacting with a quasiclassical
cantilever. It was found that in a similar fashion to the Stern-Gerlach
interferometer the quantum dynamics generates a quantum superposition of two
quasiclassical trajectories of the cantilever which are related to the two spin
projections on the direction of the effective magnetic field in the rotating
reference frame. Our results show that quantum jumps will not prevent a
single-spin measurement if the coupling between the cantilever vibrations and
the spin is small in comparison with the amplitude of the radio-frequency
external field.",0108025v1
2007-06-01,Conserved spin Hall conductance in two dimensional electron gas in a perpendicular magnetic field,"Using the microscopic theory of the conserved spin current [Phys. Rev. Lett.
\textbf{96}, 076604 (2006)], we investigate the spin Hall effect in the two
dimensional electron gas system with a perpendicular magnetic field. The spin
Hall conductance $\sigma_{\mu\nu}^{s}$ as a response to the electric field
consists of two parts, i.e., the conventional part $\sigma_{\mu\nu}^{s0}$ and
the spin torque dipole correction $\sigma_{\mu\nu}^{s\tau}$. It is shown that
the spin-orbit coupling competes with Zeeman splitting by introducing
additional degeneracies between different Landau levels at certain values of
magnetic field. These degeneracies, if occurring at the Fermi level, turn to
give rise to resonances in both $\sigma_{\mu\nu}^{s0}$ and $\sigma_{\mu\nu
}^{s\tau}$ in spin Hall conductance. Remarkably, both of these two components
have the same sign in the wide range of variation in the magnetic field, which
result in an overall enhancement of the total spin Hall current. In particular,
the magnitude of $\sigma_{\mu\nu}^{s\tau}$ is much larger than that of
$\sigma_{\mu\nu}^{s0}$ around the resonance.",0706.0047v1
2007-10-11,The role of spin noise in the detection of nanoscale ensembles of nuclear spins,"When probing nuclear spins in materials on the nanometer scale, random
fluctuations of the spin polarization will exceed the mean Boltzmann
polarization for sample volumes below about (100nm)^3. In this work, we use
magnetic resonance force microscopy to observe nuclear spin fluctuations in
real time. We show how reproducible measurements of the polarization variance
can be obtained by controlling the spin correlation time and rapidly sampling a
large number of independent spin configurations. A protocol to periodically
randomize the spin ensemble is demonstrated, allowing significant improvement
in the signal-to-noise ratio for nanometer-scale magnetic resonance imaging.",0710.2323v2
2010-03-25,Creation and manipulation of entanglement in spin chains far from equilibrium,"We investigate creation, manipulation, and steering of entanglement in spin
chains from the viewpoint of quantum communication between distant parties. We
demonstrate how global parametric driving of the spin-spin coupling and/or
local time-dependent Zeeman fields produce a large amount of entanglement
between the first and the last spin of the chain. This occurs whenever the
driving frequency meets a resonance condition, identified as ""entanglement
resonance"". Our approach marks a promising step towards an efficient quantum
state transfer or teleportation in solid state system. Following the reasoning
of Zueco et al. [1], we propose generation and routing of multipartite
entangled states by use of symmetric tree-like structures of spin chains.
Furthermore, we study the effect of decoherence on the resulting spin
entanglement between the corresponding terminal spins.",1003.4846v1
2013-02-22,Landau-Zener dynamics of a nanoresonator containing a tunneling spin,"We study the Landau-Zener dynamics of a tunneling spin coupled to a torsional
resonator. For strong spin-phonon coupling, when the oscillator frequency is
large compared to the tunnel splitting, the system exhibits multiple
Landau-Zener transitions. Entanglement of spin and mechanical angular momentum
results in abrupt changes of oscillator dynamics which coincide in time with
spin transitions. We show that a large number of spins on a single oscillator
coupled only through the in-phase phonon field behaves as a single large spin,
greatly enhancing the spin-phonon coupling. We compare purely quantum and
semiclassical dynamics of the system and discuss their experimental
realizations. An experiment is proposed in which the field sweep is used to
read out the exact quantum state of the mechanical resonator.",1302.5726v1
2013-04-11,Controlling a Nanowire Spin-Orbit Qubit via Electric-Dipole Spin Resonance,"A semiconductor nanowire quantum dot with strong spin-orbit coupling (SOC)
can be used to achieve a spin-orbit qubit. In contrast to a spin qubit, the
spin-orbit qubit can respond to an external ac electric field, an effect called
electric-dipole spin resonance. Here we develop a theory that can apply in the
strong SOC regime. We find that there is an optimal SOC strength
\eta_{opt}=\sqrt{2}/2, where the Rabi frequency induced by the ac electric
field becomes maximal. Also, we show that both the level spacing and the Rabi
frequency of the spin-orbit qubit have periodic responses to the direction of
the external static magnetic field. These responses can be used to determine
the SOC in the nanowire.",1304.3257v2
2013-04-28,Extrinsic spin Hall effect induced by resonant skew scattering in graphene,"We show that the extrinsic spin Hall effect can be engineered in monolayer
graphene by decoration with small doses of adatoms, molecules, or nanoparticles
originating local spin-orbit perturbations. The analysis of the single impurity
scattering problem shows that intrinsic and Rashba spin-orbit local couplings
enhance the spin Hall effect via skew scattering of charge carriers in the
resonant regime. The solution of the transport equations for a random ensemble
of spin-orbit impurities reveals that giant spin Hall currents are within the
reach of the current state of the art in device fabrication. The spin Hall
effect is robust with respect to thermal fluctuations and disorder averaging.",1304.7511v3
2013-08-19,A Universal Method for Separating Spin Pumping from Spin Rectification Voltage of Ferromagnetic Resonance,"We develop a method for universally resolving the important issue of
separating spin pumping (SP) from spin rectification (SR) signals in bilayer
spintronics devices. This method is based on the characteristic distinction of
SP and SR, as revealed in their different angular and field symmetries. It
applies generally for analyzing charge voltages in bilayers induced by the
ferromagnetic resonance (FMR), independent of FMR line shape. Hence, it solves
the outstanding problem that device specific microwave properties restrict the
universal quantification of the spin Hall angle in bilayer devices via FMR
experiments. Furthermore, it paves the way for directly measuring the nonlinear
evolution of spin current generated by spin pumping. The spin Hall angle in a
Py/Pt bilayer is thereby directly measured as 0.021$\pm$0.015 up to a large
precession cone angle of about 20$^{\circ}$.",1308.4041v3
2014-04-08,Ferromagnetic resonance spin pumping in CoFeB with highly resistive non-magnetic electrodes,"The relative contribution of spin pumping and spin rectification from the
ferromagnetic resonance of CoFeB/non-magnetic bilayers was investigated as a
function of non-magnetic electrode resistance. Samples with highly resistive
electrodes of Ta or Ti exhibit a stronger spin rectification signal, which may
result in over-(or under-)estimation of the spin Hall angle of the materials,
while those with low resistive electrodes of Pt or Pd show the domination of
the inverse spin Hall effect from spin pumping. By comparison with samples of
single FM layer and an inverted structure, we provide a proper analysis method
to extract spin pumping contribution.",1404.1993v1
2015-03-25,Intercombination Effects in Resonant Energy Transfer,"We investigate the effect of intercombination transitions in excitation
hopping processes such as those found in F\""orster resonance energy transfer.
Taking strontium Rydberg states as our model system, the breakdown of
$LS$-coupling leads to weakly allowed transitions between Rydberg states of
different spin quantum number. We show that the long-range interactions between
two Rydberg atoms can be affected by these weakly allowed spin transitions, and
the effect is greatest when there is a near-degeneracy between the initial
state and a state with a different spin quantum number. We also consider a case
of four atoms in a spin chain, and show that a spin impurity can resonantly hop
along the chain. By engineering the many-body energy levels of the spin-chain,
the breakdown of $LS$ coupling due to inter-electronic effects in individual
atoms can be mapped onto a spatial separation of the total spin and the total
orbital angular momentum along the spin chain.",1503.07417v4
2015-05-12,Spin-Orbit Coupling Fluctuations as a Mechanism of Spin Decoherence,"We discuss a general framework to address spin decoherence resulting from
fluctuations in a spin Hamiltonian. We performed a systematic study on spin
decoherence in the compound K$_6$[V$_{15}$As$_6$O$_{42}$(D$_2$O)] $\cdot$
8D$_2$O, using high-field Electron Spin Resonance (ESR). By analyzing the
anisotropy of resonance linewidths as a function of orientation, temperature
and field, we find that the spin-orbit term is a major decoherence source. The
demonstrated mechanism can alter the lifetime of any spin qubit and we discuss
how to mitigate it by sample design and field orientation.",1505.03177v2
2015-11-05,Cassini states for black hole binaries,"Cassini states correspond to the equilibria of the spin axis of a body when
its orbit is perturbed. They were initially described for planetary satellites,
but the spin axes of black hole binaries also present this kind of equilibria.
In previous works, Cassini states were reported as spin-orbit resonances, but
actually the spin of black hole binaries is in circulation and there is no
resonant motion. Here we provide a general description of the spin dynamics of
black hole binary systems based on a Hamiltonian formalism. In absence of
dissipation the problem is integrable and it is easy to identify all possible
trajectories for the spin for a given value of the total angular momentum. As
the system collapses due to radiation reaction, the Cassini states are shifted
to different positions, which modifies the dynamics around them. This is why
the final spin distribution may differ from the initial one. Our method
provides a simple way of predicting the distribution of the spin of black hole
binaries at the end of the inspiral phase.",1511.01890v2
2015-11-20,Hyperfine interaction mediated electric-dipole spin resonance: the role of frequency modulation,"The electron spin in a semiconductor quantum dot can be coherently controlled
by an external electric field, an effect called electric-dipole spin resonance
(EDSR). Several mechanisms can give rise to the EDSR effect, among which there
is a hyperfine mechanism, where the spin-electric coupling is mediated by the
electron-nucleus hyperfine interaction. Here, we investigate the influence of
frequency modulation (FM) on the spin-flip efficiency. Our results reveal that
FM plays an important role in the hyperfine mechanism. Without FM, the electric
field almost cannot flip the electron spin; the spin-flip probability is only
about 20%. While under FM, the spin-flip probability can be improved to
approximately 70%. In particular, we find that the modulation amplitude has a
lower bound, which is related to the width of the fluctuated hyperfine field.",1511.06503v2
2016-02-11,Probing ultrafast spin dynamics in the antiferromagnetic multiferroic HoMnO$_3$ through a magnon resonance,"We demonstrate a new approach for directly measuring the ultrafast energy
transfer between elec- trons and magnons, enabling us to track spin dynamics in
an antiferromagnet (AFM). In multiferroic HoMnO3, optical photoexcitation
creates hot electrons, after which changes in the spin order are probed with a
THz pulse tuned to a magnon resonance. This reveals a photoinduced
transparency, which builds up over several picoseconds as the spins heat up due
to energy transfer from hot elec- trons via phonons. This spin-lattice
thermalization time is ?10 times faster than that of typical ferromagnetic (FM)
manganites. We qualitatively explain the fundamental differences in
spin-lattice thermalization between FM and AFM systems and apply a Boltzmann
equation model for treating AFMs. Our work gives new insight into spin-lattice
thermalization in AFMs and demonstrates a new approach for directly monitoring
the ultrafast dynamics of spin order in these systems.",1602.03872v2
2016-09-07,Spin-Polarized Surface Resonances Accompanying Topological Surface State Formation,"Topological insulators host spin-polarized surface states born out of the
energetic inversion of bulk bands driven by the spin-orbit interaction. Here we
discover previously unidentified consequences of band-inversion on the surface
electronic structure of the topological insulator Bi$_2$Se$_3$. By performing
simultaneous spin, time, and angle-resolved photoemission spectroscopy, we map
the spin-polarized unoccupied electronic structure and identify a surface
resonance which is distinct from the topological surface state, yet shares a
similar spin- orbital texture with opposite orientation. Its momentum-
dependence and spin texture imply an intimate connection with the topological
surface state. Calculations show these two distinct states can emerge from
trivial Rashba-like states that change topology through the spin-orbit-induced
band inversion. This work thus provides a compelling view of the coevolution of
surface states through a topological phase transition, enabled by the unique
capability of directly measuring the spin-polarized unoccupied band structure.",1609.01842v1
2016-09-07,Cu nuclear magnetic resonance study of charge and spin stripe order in La$_{1.875}$Ba$_{0.125}$CuO$_4$,"We present a Cu nuclear magnetic/quadrupole resonance study of the charge
stripe ordered phase of LBCO, with detection of previously unobserved
('wiped-out') signal. We show that spin-spin and spin-lattice relaxation rates
are strongly enhanced in the charge ordered phase, explaining the apparent
signal decrease in earlier investigations. The enhancement is caused by
magnetic, rather than charge fluctuations, conclusively confirming the
long-suspected assumption that spin fluctuations are responsible for the
wipeout effect. Observation of the full Cu signal enables insight into the spin
and charge dynamics of the stripe-ordered phase, and measurements in external
magnetic fields provide information on the nature and suppression of spin
fluctuations associated with charge order. We find glassy spin dynamics, in
agreement with previous work, and incommensurate static charge order with
charge modulation amplitude similar to other cuprate compounds, suggesting that
the amplitude of charge stripes is universal in the cuprates.",1609.02162v1
2017-12-07,Spin-strain interaction in nitrogen-vacancy centers in diamond,"The interaction of solid-state electronic spins with deformations of their
host crystal is an important ingredient in many experiments realizing quantum
information processing schemes. Here, we theoretically characterize that
interaction for a nitrogen-vacancy (NV) center in diamond. We derive the
symmetry-allowed Hamiltonian describing the interaction between the
ground-state spin-triplet electronic configuration and the local strain. We
numerically calculate the six coupling-strength parameters of the Hamiltonian
using density functional theory, and propose an experimental setup for
measuring those coupling strengths. The importance of this interaction is
highlighted by the fact that it enables to drive spin transitions, both
magnetically allowed and forbidden, via mechanically or electrically driven
spin resonance. This means that the ac magnetic field routinely used in a wide
range of spin-resonance experiments with NV centers could in principle be
replaced by ac strain or ac electric field, potentially offering lower power
requirements, simplified device layouts, faster spin control, and local
addressability of electronic spin qubits.",1712.02684v1
2017-02-15,Topological Properties of a Coupled Spin-Photon System Induced by Damping,"We experimentally examine the topological nature of a strongly coupled
spin-photon system induced by damping. The presence of both spin and photonic
losses results in a non-Hermitian system with a variety of exotic phenomena
dictated by the topological structure of the eigenvalue spectra and the
presence of an exceptional point (EP), where the coupled spin-photon
eigenvectors coalesce. By controlling both the spin resonance frequency and the
spin-photon coupling strength we observe a resonance crossing for
cooperativities above one, suggesting that the boundary between weak and strong
coupling should be based on the EP location rather than the cooperativity.
Furthermore we observe dynamic mode switching when encircling the EP and
identify the potential to engineer the topological structure of coupled
spin-photon systems with additional modes. Our work therefore further
highlights the role of damping within the strong coupling regime, and
demonstrates the potential and great flexibility of spin-photon systems for
studies of non-Hermitian physics.",1702.04797v2
2019-05-20,Dual-frequency spin resonance spectroscopy of diamond nitrogen-vacancy centers in zero magnetic field,"The methods for controlling spin states of negatively charged
nitrogen-vacancy (NV) centers using microwave (MW) or radiofrequency (RF)
excitation fields for electron spin and nuclear spin transitions are effective
in strong magnetic fields where a level anti-crossing (LAC) occurs. A LAC can
also occur at zero field in the presence of transverse strain or electric
fields in the diamond crystal, leading to mixing of the spin states. In this
paper, we investigate zero-field LAC of NV centers using dual-frequency
excitation spectroscopy. Under RF modulation of the spin states, we observe
sideband transitions and Autler-Townes splitting in the optically detected
magnetic resonance (ODMR) spectra. Numerical simulations show that the
splitting originates from Landau-Zener transition between electron spin
|$\pm$1> states, which potentially provides a new way of manipulating NV center
spin states in zero or weak magnetic field.",1905.08158v1
2020-03-17,Dispersive Readout of Room Temperature Spin Qubits,"We demonstrate dispersive readout of the spin of an ensemble of
Nitrogen-Vacancy centers in a high-quality dielectric microwave resonator at
room temperature. The spin state is inferred from the reflection phase of a
microwave signal probing the resonator. Time-dependent tracking of the spin
state is demonstrated, and is employed to measure the T1 relaxation time of the
spin ensemble. Dispersive readout provides a microwave interface to solid state
spins, translating a spin signal into a microwave phase shift. We estimate that
its sensitivity can outperform optical readout schemes, owing to the high
accuracy achievable in a measurement of phase. The scheme is moreover
applicable to optically inactive spin defects and it is non-destructive, which
renders it insensitive to several systematic errors of optical readout and
enables the use of quantum feedback.",2003.07562v1
2020-11-19,Spin Structure and Resonant Driving of Spin-1/2 Defects in SiC,"Transition metal (TM) defects in silicon carbide have favorable spin
coherence properties and are suitable as quantum memory for quantum
communication. To characterize TM defects as quantum spin-photon interfaces, we
model defects that have one active electron with spin 1/2 in the atomic $D$
shell. The spin structure, as well as the magnetic and optical resonance
properties of the active electron emerge from the interplay of the crystal
potential and spin-orbit coupling and are described by a general model derived
using group theory. We find that the spin-orbit coupling leads to additional
allowed transitions and a modification of the $g$-tensor. To describe the
dependence of the Rabi frequency on the magnitude and direction of the static
and driving fields, we derive an effective Hamiltonian. This theoretical
description can also be instrumental to perform and optimize spin control in TM
defects.",2011.09987v1
2021-02-04,Resonant spin amplification in Faraday geometry,"We demonstrate the realization of the resonant spin amplification (RSA)
effect in Faraday geometry where a magnetic field is applied parallel to the
optically induced spin polarization so that no RSA is expected. However, model
considerations predict that it can be realized for a central spin interacting
with a fluctuating spin environment. As a demonstrator, we choose an ensemble
of singly-charged (In,Ga)As/GaAs quantum dots, where the resident electron
spins interact with the surrounding nuclear spins. The observation of RSA in
Faraday geometry requires intense pump pulses with a high repetition rate and
can be enhanced by means of the spin-inertia effect. Potentially, it provides
the most direct and reliable tool to measure the longitudinal $g$ factor of the
charge carriers.",2102.02780v2
2021-08-20,Spin-to-Charge conversion with electrode confinement in diamond,"The nitrogen-vacancy (NV) center in diamond has a wide range of potential
applications in quantum metrology, communications and computation. The key to
its use lies in how large the optical spin contrast is and the associated
fidelity of spin state readout. In this paper we propose a new mechanism for
improving contrast with a spin-to-charge protocol that relies on the use of an
external electrode and cryogenic temperatures to discretize the diamond
conduction band for spin-selective resonant photoionization. We use effective
mass theory to calculate the discrete eigenenergies in this new system and use
them to formulate a new spin-to-charge protocol that involves resonant
photoionization out the NV ground state into the diamond conduction band. The
major sources of broadening are also addressed which guide the design of the
experiment. With this mechanism we theorise an optical spin contrast that and
an associated spin readout fidelity of 85%. This significant improvement can be
applied to a number of cryogenic quantum technologies.",2108.09027v1
2021-01-06,Spin-transport in an organic semiconductor without free charge carrier involvement,"We have experimentally tested the hypothesis of free charge carrier mediated
spin-transport in the small molecule organic semiconductor Alq3 at room
temperature. A spin current was pumped into this material by pulsed
ferromagnetic resonance of an adjacent NiFe layer, while a charge current
resulting from this spin current via the inverse spin-Hall effect (ISHE) was
detected in a Pt layer adjacent on the other side of the Alq3 layer, confirming
a pure spin current through the Alq3 layer. Charge carrier spin states in Alq3,
were then randomized by simultaneous application of electron paramagnetic
resonance (EPR). No influence of the EPR excitation on the ISHE current was
found, implying that spin-transport is not mediated by free charge-carriers in
Alq3.",2101.02140v1
2021-05-22,Photoinduced spin-Hall resonance in a k^3-Rashba spin-orbit coupled two dimensional hole system,"We study the band structure modulation and spin-Hall effect of a
two-dimensional heavy-hole system with $k^3$-Rashba spin-orbit coupling (RSOC),
irradiated by linearly polarized light. We find that the band structure becomes
anisotropic under the illumination by the light. Most remarkably, a pair of
additional spin-degeneracy points (apart from $\Gamma$ point) emerge in the
energy dispersion, the locations of which are solely determined by the strength
of the amplitude of the incident light. If this degeneracy occurs around the
Fermi level, the spin-Hall conductivity (SHC) exhibits a resonance. Away from
the degeneracy points, the light rotates the average spin polarization. The
possible effects of $k^3$-Dresselhaus spin-orbit coupling are also discussed.",2105.10732v2
2022-07-21,Probing dynamics of a two-dimensional dipolar spin ensemble using single qubit sensor,"Understanding the thermalization dynamics of quantum many-body systems at the
microscopic level is among the central challenges of modern statistical
physics. Here we experimentally investigate individual spin dynamics in a
two-dimensional ensemble of electron spins on the surface of a diamond crystal.
We use a near-surface NV center as a nanoscale magnetic sensor to probe
correlation dynamics of individual spins in a dipolar interacting surface spin
ensemble. We observe that the relaxation rate for each spin is significantly
slower than the naive expectation based on independently estimated dipolar
interaction strengths with nearest neighbors and is strongly correlated with
the timescale of the local magnetic field fluctuation. We show that this
anomalously slow relaxation rate is due to the presence of strong dynamical
disorder and present a quantitative explanation based on dynamic resonance
counting. Finally, we use resonant spin-lock driving to control the effective
strength of the local magnetic fields and reveal the role of the dynamical
disorder in different regimes. Our work paves the way towards microscopic study
and control of quantum thermalization in strongly interacting disordered spin
ensembles.",2207.10688v2
2023-09-05,Dynamics of anisotropic frustrated antiferromagnet Cs2CoBr4 in a spin-liquid regime,"Cs2CoBr4 is a triangular-lattice antiferromagnet which can be viewed as
weakly interacting spin chains due to spatially anisotropic frustrating
exchange couplings. The spin-orbit interaction in Co(2+) spin-3/2 ions leads to
a strong easy-plane single-ion anisotropy which allows to consider the
low-energy spin dynamics of this system using an anisotropic pseudospin-1/2
model. By means of the electron spin resonance (ESR) technique, we study the
spin dynamics of Cs2CoBr4 in magnetic field in a spin-liquid regime, i.e.,
above the N'eel temperature of 1.3 K but below the temperature of the crossover
to in-chain correlations of pseudospins (6 K). Our experiments reveal two
bright branches of excitations which strongly differ both from excitations in
the low-temperature ordered phases and from high-temperature paramagnetic
resonance of uncorrelated pseudospins and spins. These two branches are
interpreted as excitations with zero momentum of an anisotropic spin-1/2 chain.
Besides, we observe several weak modes of unknown origin which arise mostly as
satellites of one of the bright modes.",2309.02266v1
2023-10-24,Measuring nuclear spin qubits by qudit-enhanced spectroscopy in Silicon Carbide,"Nuclear spins with hyperfine coupling to single electron spins are highly
valuable quantum bits. In this work we probe and characterise the particularly
rich nuclear spin environment around single silicon vacancy color-centers (V2)
in 4H-SiC. By using the electron spin-3/2 qudit as a 4 level sensor, we
identify several groups of $^{29}$Si and $^{13}$C nuclear spins through their
hyperfine interaction. We extract the major components of their hyperfine
coupling via optical detected nuclear resonance, and assign them to shell
groups in the crystal via the DFT simulations. We utilise the ground state
level anti-crossing of the electron spin for dynamic nuclear polarization and
achieve a nuclear spin polarization of up to $98\pm6\,\%$. We show that this
scheme can be used to detect the nuclear magnetic resonance signal of
individual spins and demonstrate their coherent control. Our work provides a
detailed set of parameters for future use of SiC as a multi-qubit memory and
quantum computing platform.",2310.15557v1
2015-12-05,Kinetic theory of spin-polarized systems in electric and magnetic fields with spin-orbit coupling: II. RPA response functions and collective modes,"The spin and density response functions in the random phase approximation
(RPA) are derived by linearizing the kinetic equation including a magnetic
field, the spin-orbit coupling, and mean fields with respect to an external
electric field. Different polarization functions appear describing various
precession motions showing Rabi satellites due to an effective Zeeman field.
The latter turns out to consist of the mean-field magnetization, the magnetic
field, and the spin-orbit vector. The collective modes for charged and neutral
systems are derived and a threefold splitting of the spin waves dependent on
the polarization and spin-orbit coupling is shown. The dielectric function
including spin-orbit coupling, polarization and magnetic fields is presented
analytically for long wave lengths and in the static limit. The dynamical
screening length as well as the long-wavelength dielectric function shows an
instability in charge modes, which are interpreted as spin segregation and
domain formation. The spin response describes a crossover from damped
oscillatory behavior to exponentially damped behavior dependent on the
polarization and collision frequency. The magnetic field causes ellipsoidal
trajectories of the spin response to an external electric field and the
spin-orbit coupling causes a rotation of the spin axes. The spin-dephasing
times are extracted and discussed in dependence on the polarization, magnetic
field, spin-orbit coupling and single-particle relaxation times.",1512.01661v1
2013-01-15,Travelling Wave Magnetic Resonance Imaging at 3 Tesla,"Waveguides have been successfully used to generate magnetic resonance images
at 7 T with whole-body systems. The bore limits the magnetic resonance signal
transmitted because its specific cut-off frequency is greater than the majority
of resonant frequencies. This restriction can be overcome by using a
parallel-plate waveguide whose cut-off frequency is zero for the transversal
electric modes and it can propagate any frequency. To investigate the potential
benefits for whole-body imaging at 3 T, we compare numerical simulations at 1.5
T, 3 T, 7 T, and 9 T via the propagation of the parallel-plate waveguide
principal mode filled with a cylindrical phantom and two surface coils. B1
mapping was computed to investigate the feasibility of this approach at 3T. The
point spread function method was used to measure the imager performance for the
traveling-wave magnetic resonance imaging experiment. Human leg images were
acquired to experimentally validate this approach. The principal mode shows
very little field magnitude variations along the propagation direction at 3 T
when compared to other higher resonant frequencies. The B1 mapping showed that
it is possible to conduct experiments using the traveling-wave approach at 128
MHz. The point spread function results showed a good scanner performance for
these type of experiments. Leg images were obtained with the whole-body
birdcage coil and the waveguide with two circular coils for comparison
purposes. The simulated and in vivo traveling-wave results correspond very well
for both magnetic field and specific absorption rate. A pretty similar
performance was observed for the traveling-wave approach and the conventional
one. We have demonstrated the feasibility of traveling-wave magnetic resonance
imaging at 3T for whole-body magnetic resonance systems, using a parallel-plate
waveguide with standard pulse sequences and only one coil array.",1301.3426v1
2003-04-17,Field-Induced Spin-Density-Wave Phases in Quasi-One-Dimensional Conductors: Theory versus Experiment,"We show that ""Quantizied Nesting"" model misses important features of the
magnetic field-induced spin-density-wave (FISDW) phase diagram. Among them are:
1) the FISDW wave vector is not strictly quantized; 2) in some compounds, the
FISDW diagram consists of two regions: a) at low temperatures, there are jumps
of the wave vector (i.e., the first order transitions between FISDW phases), b)
at high temperatures the jumps and the first order transitions disappear but
the wave vector is still a non-trivial function of a magnetic field. These are
in agreement with the experiments on (TMTSF)2PF6.",0304406v1
2005-10-31,Coexistence of double-Q spin density wave and multi-Q pair density wave in cuprate oxide superconductors,"Spatial 4a x 4a modulations, with a the lattice constant of CuO_2 planes, or
the so called checkerboards can arise from double-Q spin density wave (SDW)
with Q_1 = (pm pi/a, pm 3 pi/4a) and Q_2 = (pm 3 pi/4a, pm pi/a). When multi-Q
pair density wave, that is, the condensation of d gamma-wave Cooper pairs with
zero total momenta, pm 2Q_1, pm 2Q_2, pm 4Q_1, pm 4Q_2, and so on is induced by
the SDW, gaps can have fine structures similar to those of the so called
zero-temperature pseudogaps.",0510829v1
2017-01-05,Wave Packet Dynamics in the Majorana Equation,"In the Majorana equation for particles with arbitrary spin, wave packets
occur due to not only the uncertainty that affects position and momentum but
also due to infinite components with decreasing mass that form the Majorana
spinor. In this paper, we prove that such components contribute to increase the
spreading of wave packets. Moreover, Zitterbewegung takes place in both the
time propagation of Dirac wave packets and in Majorana wave packets. However,
it shows a peculiar fine structure. Finally, group velocity always remains
subluminal and contributions due to infinite components decrease progressively
as spin increases.",1701.03012v1
2004-02-26,Superslow Self-Organized Motions in a Multimode Microwave Phonon Laser (Phaser) under Resonant Destabilization of Stationary Acoustic Stimulated Emission,"Two qualitatively different kinds of resonant destabilization of phonon
stimulated emission (SE) are experimentally revealed for periodically forced
multimode ruby phaser (phonon laser) operating at SE frequencies about 9 GHz,
i.e. at microwave acoustic wavelengths of 1 micron. The inversion state of
Cromium(3+) spin-system in ruby was created by electromagnetic pump at 23 GHz.
Under deep modulation of pump power at low frequencies OMEGA_m = 70-200 Hz
deterministic chaotic reconfigurations of the acoustic microwave power spectra
(AMPS) were observed. This range of SE destabilization corresponds to the
relaxational resonance that is well known for optical class-B lasers. Outside
the relaxational resonance range, namely at ultra-low (infrasonic) frequencies
OMEGA_m about 10 Hz, the other type of resonant destabilization of stationary
phonon SE was observed by us for the first time. This new nonlinear resonance
(we call it lambda-resonance) manifests itself as very slow and periodically
repeated self-reconfigurations of AMPS. Near the vertex of lambda-resonance the
period of AMPS self-reconfigurations takes giant values of several hours (at
T=1.8 K). The second type of SE resonant destabilization is explained in terms
of antiphase energy exchange between acoustic SE modes in a modulated phaser.
The role of polarized nuclear spin-reservoir (formed by Aluminium-27 nuclei of
the ruby crystalline matrix) in these superslow self-organized motions is
discussed. PACS: 05.65.+b, 42.65.Sf, 43.35.+d",0402640v1
2016-12-22,Frequency control and coherent excitation transfer in a nanostring resonator network,"Coupling, synchronization, and non-linear dynamics of resonator modes are
omnipresent in nature and highly relevant for a multitude of applications
ranging from lasers to Josephson arrays and spin torque oscillators.
Nanomechanical resonators are ideal candidates to study these effects on a
fundamental level and to realize all-mechanical platforms for information
processing and storage. For larger resonator networks, however, this requires
the ability to tune the mode frequencies selectively and to operate the
resonators in the strong coupling regime. Here, we present a proof-of-principle
realization of a resonator network consisting of two high-quality nanostring
resonators, coupled mechanically by a shared support. First, we demonstrate
that we can control the fundamental mode frequencies of both nanostrings
independently by a strong drive tone resonant with one of the higher harmonics
of the network, rendering local control gates redundant. The tuning mechanism
relies on an effective increase of the pre-stress in a highly excited
nanostring, known as geometric nonlinearity. Using this selective frequency
control of the individual nanomechanical resonators, we investigate the
coherent dynamics of the resonator network, which is a classical model system
showing several of the characteristic features of strongly coupled quantum
systems. In particular, we demonstrate mode splitting, classical Rabi
oscillations, as well as adiabatic and diabatic transitions between the coupled
states representing the classical analog of Landau-Zener tunneling. Therefore,
this coupling and tuning concept opens the path to a selective phonon transfer
between two spatially separated mechanical resonators.",1612.07511v1
2008-02-21,Liquid Density Sensing Using Resonant Flexural Plate Wave Device with Sol-Gel PZT Thin Films,"This paper presents the design, fabrication and preliminary experimental
results of a flexure plate wave (FPW) resonator using sol-gel derived lead
zirconate titanates (PZT) thin films. The resonator adopts a two-port structure
with reflecting grates on the composite membrane of PZT and SiNx. The design of
the reflecting grate is derived from a SAW resonator model using COM theory to
produce a sharp resonant peak. The comparison between the mass and the
viscosity effects from the theoretical expression illustrates the applications
and the constraints of the proposed device in liquid sensing. Multiple coatings
of sol-gel derived PZT films are adopted because of the cost advantage and the
high electromechanical coupling effect over other piezoelectric films. The
fabrication issues of the proposed material structure are addressed.
Theoretical estimations of the mass and the viscosity effects are compared with
the experimental results. The resonant frequency has a good linear correlation
with the density of low viscosity liquids, which demonstrate the feasibility of
the proposed device.",0802.3043v1
2010-05-03,$ρN$ resonance dynamics in the proton nucleus reaction,"The strong coupling of rho meson to the nucleon produces $s$ and $p$ wave rho
meson nucleon $(\rho N)$ resonances. In a nucleus, the $\rho N$ resonance-hole
polarization generates the optical potential or self-energy for the rho meson.
The scattering of rho meson due to this potential provides valuable
informations about the $\rho N$ resonance dynamics in a nucleus. To investigate
it, we use this potential to calculate the mass distribution spectrum for the
$\rho$ meson produced coherently in the proton nucleus reaction. The cross
sections arising due to $s$ and $p$ wave $\rho N$ resonances have been
presented. The coherent and incoherent contributions to the cross sections due
to these resonances are compared. In addition, the calculated results due to
non-relativistic and relativistic $\rho$ meson self-energy are illustrated.",1005.0187v2
2014-09-17,Nonhermitian transport effects in coupled-resonator optical waveguides,"Coupled-resonator optical waveguides (CROWs) are known to have interesting
and useful dispersion properties. Here, we study the transport in these
waveguides in the general case where each resonator is open and asymmetric,
i.e., is leaky and possesses no mirror-reflection symmetry. Each individual
resonator then exhibits asymmetric backscattering between clockwise and
counterclockwise propagating waves, which in combination with the losses
induces non-orthogonal eigenmodes. In a chain of such resonators, the coupling
between the resonators induces an additional source of non-hermiticity, and a
complex band structure arises. We show that in this situation the group
velocity of wave packets differs from the velocity associated with the
probability density flux, with the difference arising from a non-hermitian
correction to the Hellmann-Feynman theorem. Exploring these features
numerically in a realistic scenario, we find that the complex band structure
comprises almost-real branches and complex branches, which are joined by
exceptional points, i.e., nonhermitian degeneracies at which not only the
frequencies and decay rates coalesce but also the eigenmodes themselves. The
non-hermitian corrections to the group velocity are largest in the regions
around the exceptional points.",1409.5037v1
2017-07-04,Tuning of bound states in the continuum by waveguide rotation,"We consider acoustic wave transmission in non axisymmetric waveguide which
consists of cylindrical resonator and two semi-infinite cylindrical waveguides
whose axes are shifted relative to the resonator axis and each other by
azimuthal angle $\Delta\phi$. We show that for rotation of one of attached
waveguides the coupling matrix elements of the eigenmodes of resonator
classified by the integer $m$ and propagating mode of the waveguide acquire
phase factor $e^{im\Delta\phi}$. That crucially effect Fano resonances and
creates an analog of faucet opening and closing wave flux under rotation of the
waveguide. We show that under the rotation of the waveguide and variation of
the length of resonator numerous bound states in the continuum occur
complimenting by the Fano resonance collapse.",1707.00864v1
2017-12-12,Topological interface modes in local resonant acoustic systems,"Topological phononic crystals (PCs) are periodic artificial structures which
can support nontrivial acoustic topological bands, and their topological
properties are linked to the existence of topological edge modes. Most previous
studies focused on the topological edge modes in Bragg gaps which are induced
by lattice scatterings. While local resonant gaps would be of great use in
subwavelength control of acoustic waves, whether it is possible to achieve
topological interface states in local resonant gaps is a question. In this
article, we study the topological bands near local resonant gaps in a
time-reversal symmetric acoustic systems and elaborate the evolution of band
structure using a spring-mass model. Our acoustic structure can produce three
band gaps in subwavelength region: one originates from local resonance of unit
cell and the other two stem from band folding. It is found that the topological
interface states can only exist in the band folding induced band gaps but never
appear in the local resonant band gap. The numerical simulation perfectly
agrees with theoretical results. Our study provides an approach of localizing
the subwavelength acoustic wave.",1712.04252v1
2019-11-09,Perturbation theories for symmetry-protected bound states in the continuum on two-dimensional periodic structures,"On dielectric periodic structures with a reflection symmetry in a periodic
direction, there can be antisymmetric standing waves (ASWs) that are
symmetry-protected bound states in the continuum (BICs). The BICs have found
many applications, mainly because they give rise to resonant modes of extremely
large quality-factors ($Q$-factors). The ASWs are robust to symmetric
perturbations of the structure, but they become resonant modes if the
perturbation is non-symmetric. The $Q$-factor of a resonant mode on a perturbed
structure is typically $O(1/\delta^2)$ where $\delta$ is the amplitude of the
perturbation, but special perturbations can produce resonant modes with larger
$Q$-factors. For two-dimensional (2D) periodic structures with a 1D
periodicity, we derive conditions on the perturbation profile such that the
$Q$-factors are $O(1/\delta^4)$ or $O(1/\delta^6)$. For the unperturbed
structure, an ASW is surrounded by resonant modes with a nonzero Bloch wave
vector. For 2D periodic structures, the $Q$-factors of nearby resonant modes
are typically $O(1/\beta^2)$, where $\beta$ is the Bloch wavenumber. We show
that the $Q$-factors can be $O(1/\beta^6)$ if the ASW satisfies a simple
condition.",1911.03612v1
2018-10-15,Ridge Resonance: A new Resonance Phenomenon for Silicon Photonics Harnessing Bound States in the Continuum,"We present a new resonant behavior based on bound states in the continuum in
a guided wave silicon platform. The continuum has the form of a collimated beam
of light which is confined vertically in a TE mode of a silicon slab. The bound
state is a discrete TM mode of a ridge on the silicon slab. The coupling
between the slab and ridge modes results in a single sharp resonance at the
wavelength where they phase match. We experimentally demonstrate this
phenomenon on a silicon photonic chip using foundry compatible parameters and
interface it on-chip to standard single mode silicon nanowire waveguides. The
fabricated chip exhibits a single sharp resonance near 1550 nm with a line
width of a few nanometer, an extinction ratio of 25 dB and a thermal stability
of 19.5 pm/C. We believe that this is the first demonstration of bound states
in the continuum resonance realized using guided wave components.",1810.06734v3
2018-12-19,Coherent interplay between surface acoustic waves and coupled mechanical resonators: transition from plasmon-like to surface mediated coupling,"Manipulation of mechanical motion at the micro-scale has been attracting
continuous attention, leading to the successful implementation of various
strategies with potential impact on classical and quantum information
processing. We here propose an approach based on the interplay between a pair
of localized mechanical resonators and travelling surface acoustic waves (SAW).
We demonstrate the existence of a two-sided interaction, allowing to use SAW to
trigger and control the resonator oscillation, and to manipulate the elastic
energy distribution on the substrate through resonator coupling. Observation of
the vectorial structure of the resonator motion reveals the existence of two
coupling regimes, a dipole-dipole-like interaction at small separation distance
versus a surface-mediated mechanical coupling at larger separation. These
results illustrate the potential of this platform for coherent control of
mechanical vibration at a resonator level, and reciprocally for manipulating
SAW propagation using sub-wavelength elements.",1812.07952v2
2020-08-24,Chromospheric resonances above sunspots and potential seismological applications,"Oscillations in sunspot umbrae exhibit remarkable differences between the
photosphere and chromosphere. We evaluate two competing scenarios proposed for
explaining those observations: a chromospheric resonant cavity and waves
traveling from the photosphere to upper atmospheric layers. We have employed
numerical simulations to analyze the oscillations in both models. They have
been compared with observations in the low (Na I D2) and high (He I 10830 \AA)
chromosphere. The nodes of the resonant cavity can be detected as phase jumps
or power dips, although the identification of the latter is not sufficient to
claim the existence of resonances. In contrast, phase differences between
velocity and temperature fluctuations reveal standing waves and unequivocally
prove the presence of an acoustic resonator above umbrae. Our findings offer a
new seismic method to probe active region chromospheres through the detection
of resonant nodes.",2008.10623v1
2008-06-17,Resonance enhancement of magnetic Faraday rotation,"Magnetic Faraday rotation is widely used in optics. In natural transparent
materials, this effect is very weak. One way to enhance it is to incorporate
the magnetic material into a periodic layered structure displaying a high-Q
resonance. One problem with such magneto-optical resonators is that a
significant enhancement of Faraday rotation is inevitably accompanied by strong
ellipticity of the transmitted light. More importantly, along with the Faraday
rotation, the resonator also enhances linear birefringence and absorption
associated with the magnetic material. The latter side effect can put severe
limitations on the device performance. From this perspective, we carry out a
comparative analysis of optical microcavity and a slow wave resonator. We show
that slow wave resonator has a fundamental advantage when it comes to Faraday
rotation enhancement in lossy magnetic materials.",0806.2884v1
2019-04-30,On the convergence of the normal form transformation in discrete Rossby and drift wave turbulence,"We study numerically the region of convergence of the normal form
transformation for the case of the Charney-Hasagawa-Mima (CHM) equation to
investigate whether certain finite amplitude effects can be described in normal
coordinates. We do this by taking a Galerkin truncation of four Fourier modes
making part of two triads: one resonant and one non-resonant, joined together
by two common modes. We calculate the normal form transformation directly from
the equations of motion of our reduced model, successively applying the
algorithm to calculate the transformation up to $7^\textrm{th}$ order to
eliminate all non-resonant terms, and keeping up to $8$-wave resonances. We
find that the amplitudes at which the normal form transformation diverge very
closely match with the amplitudes at which a finite-amplitude phenomenon called
$precession$ $resonance$ (Bustamante $et$ $al.$ 2014) occurs, characterised by
strong energy transfers. This implies that the precession resonance mechanism
cannot be explained using the usual methods of normal forms in wave turbulence
theory, so a more general theory for intermediate nonlinearity is required.",1904.13272v1
2019-12-03,Multi-reflection model of subwavelength grating diffraction based on simplified modal method,"A multi-reflection model of grating diffraction based on the simplified modal
method is proposed. Simulation results for a guided mode resonance Brewster
grating using our method and rigorous coupled wave analysis are presented to
verify our model. The solution of our method is in good agreement with that of
rigorous coupled wave analysis. Benefiting from its clear physical view, this
model helps us to better understand the diffraction process inside
subwavelength gratings. On the basis of the multi-reflection model, we
developed a matrix Fabry-Perot (FP) resonance condition and a single-mode
resonance condition to evaluate the resonance wavelength. These resonance
conditions may be helpful for simplifying design of guided mode resonance (GMR)
gratings.",1912.01226v1
2020-06-30,$ΛΛN$-$ΞNN$ $S$ wave resonance,"We use an existing model of the $\Lambda\Lambda N - \Xi NN$ three-body system
based in two-body separable interactions to study the $(I,J^P)=(1/2,1/2^+)$
three-body channel. For the $\Lambda\Lambda$, $\Xi N$, and $\Lambda\Lambda -
\Xi N$ amplitudes we have constructed separable potentials based on the most
recent results of the HAL QCD Collaboration. They are characterized by the
existence of a resonance just below or above the $\Xi N$ threshold in the
so-called $H$-dibaryon channel, $(i,j^p)=(0,0^+)$. A three-body resonance
appears {2.3} MeV above the $\Xi d$ threshold. We show that if the
$\Lambda\Lambda - \Xi N$ $H$-dibaryon channel is not considered, the
$\Lambda\Lambda N - \Xi NN$ $S$ wave resonance disappears. Thus, the possible
existence of a $\Lambda\Lambda N - \Xi NN$ resonance would be sensitive to the
$\Lambda\Lambda - \Xi N$ interaction. The existence or nonexistence of this
resonance could be evidenced by measuring, for example, the $\Xi d$ cross
section.",2006.16567v1
2021-03-08,Fine structure of second-harmonic resonances in χ^{(2)} optical microresonators,"Owing to the discrete frequency spectrum of whispering gallery resonators
(WGRs), the resonance and phase-matching conditions for the interacting waves
in the case of second-harmonic generation (SHG) cannot generally be fulfilled
simultaneously. To account for this, we develop a model describing SHG in WGRs
with non-zero frequency detunings at both the pump and second-harmonic
frequencies. Our model predicts strong distortions of the line shape of pump
and second-harmonic resonances for similar linewidths at both frequencies; for
much larger linewidths at the second-harmonic frequency, this behavior is
absent. Furthermore, it describes the SHG efficiency as a function of detuning.
Experimentally, one can change the WGR eigenfrequencies, and thus the relative
detuning between pump and second-harmonic waves by a number of means, for
example electro-optically and thermally. Using a lithium niobate WGR, we show
an excellent quantitative agreement for the SHG efficiency between our
experimental results and the model. Also, we show the predicted distortions of
the pump and second-harmonic resonances to be absent in the lithium niobate
WGR, but present in a cadmium silicon phosphide WGR, as expected from the
linewidths of the resonances involved.",2103.04926v1
2021-03-23,Bound states in the continuum and Fano resonances in subwavelength resonator arrays,"When wave scattering systems are subject to certain symmetries, resonant
states may decouple from the far-field continuum; they remain localized to the
structure and cannot be excited by incident waves from the far field. In this
work, we use layer-potential techniques to prove the existence of such states,
known as bound states in the continuum, in systems of subwavelength resonators.
When the symmetry is slightly broken, this resonant state can be excited from
the far field. Remarkably, this may create asymmetric (Fano-type) scattering
behaviour where the transmission is fundamentally different for frequencies on
either side of the resonant frequency. Using asymptotic analysis, we compute
the scattering matrix of the system explicitly, thereby characterizing this
Fano-type transmission anomaly.",2103.12470v1
2021-05-12,Fano interference in quantum resonances from angle-resolved elastic scattering,"Asymmetric spectral line shapes are a hallmark of interference of a
quasi-bound state with a continuum of states. Such line shapes are well known
for multichannel systems, for example, in photoionization or Feshbach
resonances in molecular scattering. On the other hand, in resonant single
channel scattering, the signature of such interference may disappear due to the
orthogonality of partial waves. Here, we show that probing the angular
dependence of the cross section allows us to unveil asymmetric Fano profiles
also in a single channel shape resonance. We observe a shift in the peak of the
resonance profile in the elastic collisions between metastable helium and
deuterium molecules with detection angle, in excellent agreement with
theoretical predictions from full quantum scattering calculations. Using a
model description for the partial wave interference, we can disentangle the
resonant and background contributions and extract the relative phase
responsible for the characteristic Fano-like profiles from our experimental
measurements.",2105.05959v2
2021-06-29,What is the resonant state in open quantum systems?,"The article reviews the theory of open quantum system from a perspective of
the non-Hermiticity that emerges from the environment with an infinite number
of degrees of freedom. The non-Hermiticity produces resonant states with
complex eigenvalues, resulting in peak structures in scattering amplitudes and
transport coefficients. After introducing the definition of resonant states
with complex eigenvalues, we answer typical questions regarding the
non-Hermiticity of open quantum systems. What is the physical meaning of the
complex eigenmomenta and eigenenergies? How and why do the resonant states
break the time-reversal symmetry that the system observes? Can we make the
probabilistic interpretation of the resonant states with diverging wave
functions? What is the physical meaning of the divergence of the wave
functions? We also present an alternative way of finding resonant states,
namely the Feshbach formalism, in which we eliminate the infinite number of the
environmental degrees of freedom. In this formalism, we attribute the
non-Hermiticity to the introduction of the retarded and advanced Green's
functions.",2106.15068v1
2021-12-13,Effect of interfacial damping on high-frequency surface wave resonance on a nanostrip-bonded substrate,"Since surface acoustic waves (SAW) are often generated on substrates to which
nanostrips are periodically attached, it is very important to consider the
effect of interface between the deposited strip and the substrate surface,
which is an unavoidable issue in manufacturing. In this paper, we propose a
theoretical model that takes into account the interface damping and calculate
the dispersion relationships both for frequency and attenuation of SAW
resonance. This results show that the interface damping has an insignificant
effect on resonance frequency, but, interestingly, attenuation of the SAW can
decrease significantly in the high frequency region as the interface damping
increases. Using picosecond ultrasound spectroscopy, we confirm the validity of
our theory; the experimental results show similar trends both for resonant
frequency and attenuation in the SAW resonance. Furthermore, the resonant
behavior of the SAW is simulated using the finite element method, and the
intrinsic cause of interface damping on the vibrating system is discussed.
These findings strongly indicate the necessity of considering interfacial
damping in the design of SAW devices.",2112.06367v1
2022-08-29,Resonant Kushi-comb-like multi-frequency radiation of oscillating two-color soliton molecules,"Nonlinear waveguides with two distinct domains of anomalous dispersion can
support the formation of molecule-like two-color pulse compounds. They consist
of two tightly bound subpulses with frequency loci separated by a vast
frequency gap. Perturbing such a two-color pulse compound triggers periodic
amplitude and width variations, reminiscent of molecular vibrations. With
increasing strength of perturbation, the dynamics of the pulse compound changes
from harmonic to nonlinear oscillations. The periodic amplitude variations
enable coupling of the pulse compound to dispersive waves, resulting in the
resonant emission of multi-frequency radiation. We demonstrate that the
location of the resonances can be precisely predicted by phase-matching
conditions. If the pulse compound consists of a pair of identical subpulses,
inherent symmetries lead to degeneracies in the resonance spectrum. Weak
perturbations lift existing degeneracies and cause a splitting of the resonance
lines into multiple lines. Strong perturbations result in more complex emission
spectra, characterized by well separated spectral bands caused by resonant
Cherenkov radiation and additional four-wave mixing processes.",2208.13829v1
2023-10-25,Kerr-Nonlinearity Assisted Exceptional Point Degeneracy in a Detuned PT-Symmetric System,"Systems operating at exceptional points (EPs) are highly responsive to small
perturbations, making them suitable for sensing applications. Although this
feature impedes the system working exactly at an EP due to imperfections
arising during the fabrication process. We propose a fast self-tuning scheme
based on Kerr nonlinearity in a coupled dielectric resonator excited through a
waveguide placed in the near-field of the resonators. We show that in a coupled
resonator with unequal Kerr-coefficients, initial distortion from EP regime can
be completely compensated. It provides an opportunity to reach very close to
the EP in a coupled resonator with detuned resonant frequencies via tuning the
intensity of the incident wave. Using time-modulation of the incident wave in
nonlinear systems to control both the gain or loss, and resonant frequencies
can be a possible approach to fully control the parameters close to an EP.",2310.16259v2
2023-12-07,Simulations of Non-Integer Upconversion in Resonant Six-Wave Scattering,"Resonant upconversion through a sixth order relativistic nonlinearity
resulting in a unique resonance was recently proposed [V. M. Malkin and N. J.
Fisch, Physical Review E 108, 045208 (2023)]. The high order resonance is a
unique non-integer multiple of a driving pump frequency resulting in a
frequency upshift by a factor of $\approx 3.73$. We demonstrate the presence,
unique requirements, and growth of this mode numerically. Through tuning waves
to high amplitude, in a mildly underdense plasma, the six-photon process may
grow more than other non-resonant, but lower order processes. The growth of the
high frequency mode remains below the nonlinear growth regime. However,
extending current numerical results to more strongly coupled resonances with
longer pulse propagation distances suggests a pathway to significant
upconversion.",2312.04699v1
1999-11-26,Acoustic Cyclotron Resonance and Giant High Frequency Magnetoacoustic Oscillations in Metals with Locally Flattened Fermi Surface,"We consider the effect of local flattening on the Fermi surface (FS) of a
metal upon geometric oscillations of the velocity and attenuation of ultrasonic
waves in the neighborhood of the acoustic cyclotron resonance. It is shown that
such peculiarities of the local geometry of the FS can lead to a significant
enhancement of both cyclotron resonance and geometric oscillations.
Characteristic features of the coupling of ultrasound to shortwave cyclotron
waves arising due to the local flattening of the FS are analyzed.
  PACS numbers 71.18.+y; 72.15.Gd; 72.15.-v",9911440v2
2000-01-03,Signature of Dynamical Localization in the Lifetime Distribution of Wave-Chaotic Dielectric Resonators,"We consider the effect of dynamical localization on the lifetimes of the
resonances in open wave-chaotic dielectric cavities. We show that dynamical
localization leads to a log-normal distribution of the resonance lifetimes
which scales with the localization length in excellent agreement with the
results of numerical calculations for open rough microcavities.",0001017v1
2004-12-14,Nonlinear Fano resonance and bistable wave transmission,"We consider a discrete model that describes a linear chain of particles
coupled to a single-site defect with instantaneous Kerr nonlinearity. We show
that this model can be regarded as a nonlinear generalization of the familiar
Fano-Anderson model, and it can generate the amplitude depended bistable
resonant transmission or reflection. We identify these effects as the nonlinear
Fano resonance, and study its properties for continuous waves and pulses.",0412341v1
2005-09-12,Backward-wave regime and negative refraction in chiral composites,"Possibilities to realize a negative refraction in chiral composites in in
dual-phase mixtures of chiral and dipole particles is studied. It is shown that
because of strong resonant interaction between chiral particles (helixes) and
dipoles, there is a stop band in the frequency area where the backward-wave
regime is expected. The negative refraction can occur near the resonant
frequency of chiral particles. Resonant chiral composites may offer a root to
realization of negative-refraction effect and superlenses in the optical
region.",0509287v1
1999-11-15,Resonant Spheres: Multifrequency Detectors of Gravitational Waves,"We discuss the capabilities of spherical antenn\ae as single multifrequency
detectors of gravitational waves. A first order theory allows us to evaluate
the coupled spectrum and the resonators readouts when the first and the second
quadrupole bare sphere frequencies are simultaneously selected for layout
tuning. We stress the existence of non-tuning influences in the second mode
coupling causing draggs in the frequency splittings. These URF effects are
relevant to a correct physical description of resonant spheres, still more if
operating as multifrequency appliances like our PHCA proposal.",9911056v1
2004-12-16,Pentaquark Resonances from Collision Times,"Having successfully explored the existing relations between the S-matrix and
collision times in scattering reactions to study the conventional baryon and
meson resonances, the method is now extended to the exotic sector. To be
specific, the collision time in various partial waves of K+ N elastic
scattering is evaluated using phase shifts extracted from the K+ N --> K+ N
data as well as from model dependent T-matrix solutions. We find several
pentaquark resonances including some low-lying ones around 1.5 to 1.6 GeV in
the P_01, P_03 and D_03 partial waves of K+ N elastic scattering.",0412240v1
2004-08-02,Conservation of resonant periodic solutions for the one-dimensional nonlinear Schroedinger equation,"We consider the one-dimensional nonlinear Schr\""odinger equation with
Dirichlet boundary conditions in the fully resonant case (absence of the
zero-mass term). We investigate conservation of small amplitude
periodic-solutions for a large set measure of frequencies. In particular we
show that there are infinitely many periodic solutions which continue the
linear ones involving an arbitrary number of resonant modes, provided the
corresponding frequencies are large enough and close enough to each other (wave
packets with large wave number).",0408017v1
2003-01-18,Statistical properties of resonance widths for open Quantum Graphs,"We connect quantum compact graphs with infinite leads, and turn them into
scattering systems. We derive an exact expression for the scattering matrix,
and explain how it is related to the spectrum of the corresponding closed
graph. The resulting expressions allow us to get a clear understanding of the
phenomenon of resonance trapping due to over-critical coupling with the leads.
Finally, we analyze the statistical properties of the resonance widths and
compare our results with the predictions of Random Matrix Theory. Deviations
appearing due to the dynamical nature of the system are pointed out and
explained.",0301021v1
1998-08-24,Solitary Waves on a Coasting High-Energy Stored Beam,"In this work we derive evolution equations for the nonlinear behavior of a
coasting beam under the influence of a resonator impedance. Using a
renormalization group approach we find a set of coupled nonlinear equations for
the beam density and the resonator voltage. Under certain conditions, these may
be analytically solved yielding solitary wave behavior, even in the presence of
significant dissipation in the resonator. We find long-lived perturbations,
i.e. droplets, which separate from the beam and decelerate towards a
quasi-equilibrium state, in good agreement with simulation results.",9808032v1
1999-09-21,Qualitative analysis of low-lying resonances of the dipositronium emerging from Ps-Ps and Ps-Ps* collisions,"An analysis of the channel wave functions is made to clarify the types of
resonance emerging from Ps-Ps and Ps-Ps* collisions. The ordering of the energy
levels of the states of the dipositronium is evaluated based on the inherent
nodal structures of wave functions and on existing theoretical results. A few
very probable low-lying narrower resonances, namely the 0+(A2), 1-(E),...,
benefiting from the centrifugal barrier have been proposed.",9909041v1
2003-04-17,Efficient photon counting and single-photon generation using resonant nonlinear optics,"The behavior of an atomic double lambda system in the presence of a strong
off-resonant classical field and a few-photon resonant quantum field is
examined. It is shown that the system possesses properties that allow a
single-photon state to be distilled from a multi-photon input wave packet. In
addition, the system is also capable of functioning as an efficient
photodetector discriminating between one- and two-photon wave packets with
arbitrarily high efficiency.",0304121v1
2004-09-01,"""Paradoxical"" coexistence of continuum of 'bound' waves and discrete set of unlimited motion states","We have combined two remarkable phenomena: resonance tunneling and Anderson
localization. It results in unexpected spectrum reverse to usual notions. It is
demonstrated by the quantum system with chaotic distribution of potential
resonance tunneling traps over the whole coordinate axis. The corresponding
spectrum contains continuum of 'bound' states (Anderson's localization) and
discrete tunneling resonances of unlimited wave propagation. It is in contrast
to the usual situation with discrete bound and continuum of scattering states.",0409004v1
2008-08-26,Pattern selection in parametrically-driven arrays of nonlinear resonators,"We study the problem of pattern selection in an array of
parametrically-driven nonlinear resonators with application to
microelectromechanical and nanoelectromechanical systems (MEMS & NEMS), using
an amplitude equation recently derived by Bromberg, Cross, and Lifshitz [PRE
73, 016214 (2006)]. We describe the transitions between standing-wave patterns
of different wave numbers as the drive amplitude is varied either
quasistatically, abruptly, or as a linear ramp in time. We find novel
hysteretic effects, which are confirmed by numerical integration of the
original equations of motion of the interacting nonlinear resonators.",0808.3589v1
2009-02-24,Optical potentials using resonance states in Supersymmetric Quantum Mechanics,"Complex potentials are constructed as Darboux-deformations of short range,
radial nonsingular potentials. They behave as optical devices which both
refracts and absorbs light waves. The deformation preserves the initial
spectrum of energies and it is implemented by means of a Gamow-Siegert function
(resonance state). As straightforward example, the method is applied to the
radial square well. Analytical derivations of the involved resonances show that
they are `quantized' while the corresponding wave-functions are shown to behave
as bounded states under the broken of parity symmetry of the related
one-dimensional problem.",0902.4052v1
2009-05-08,Variational study of the neutron resonance mode in the cuprate superconductors,"A Gutzwiller-type variational wave function is proposed for the neutron
resonance mode in the cuprate superconductors. An efficient re-weighting
technique is devised to perform variational Monte Carlo simulation on the
proposed wave function which is composed of linearly superposed Gutzwiller
projected Slater determinants. The calculation, which involves no free
parameter, predicts qualitatively correct behavior for both the energy and the
spectral weight of the resonance mode as functions of doping.",0905.1232v1
2009-09-07,Disentangling the dynamical origin of P11 Nucleon Resonances,"We show that two almost degenerate poles near the $\pi\Delta$ threshold and
the next higher mass pole in the $P_{11}$ partial wave of $\pi N$ scattering
evolve from a single bare state through its coupling with $\pi N$, $\eta N$ and
$\pi\pi N$ reaction channels. This finding provides new information on
understanding the dynamical origins of the Roper $N^*(1440)$ and $N^*(1710)$
resonances listed by Particle Data Group. Our results for the resonance poles
in other $\pi N$ partial waves are also presented.",0909.1356v2
2010-04-16,Resonance wave functions located at the Stark saddle point,"We calculate quantum mechanically exact wave functions of resonances in
spectra of the hydrogen atom in crossed external fields and prove the existence
of long-lived decaying quantum states localized at the Stark saddle point. A
spectrum of ground and excited states reproducing the nodal patterns expected
from simple quadratic and cubic expansions of the potential in the vicinity of
the saddle point can be identified. The results demonstrate the presence of
resonances in the vicinity of the saddle predicted by simple approximations.",1004.2876v2
2011-07-28,Enhanced four-wave mixing via crossover resonance in cesium vapor,"We report on the observation of enhanced four-wave mixing via crossover
resonance in a Doppler broadened cesium vapor. Using a single laser frequency,
a resonant parametric process in a double-$\Lambda$ level configuration is
directly excited for a specific velocity class. We investigate this process in
different saturation regimes and demonstrate the possibility of generating
intensity correlation and anti-correlation between the probe and conjugate
beams. A simple theoretical model is developed that accounts qualitatively well
to the observed results.",1107.5768v1
2011-09-23,Restoring of optical resonances in subwavelength hyperbolic etalons,"We give a solution to the fundamental problem of restoring optical resonances
in deep subwavelength structures by resorting to indefinite metamaterials. We
prove that a nanometric thick hyperbolic slab with very small permittivities
exhibits etalon resonances and provides high-contrast optical angular
filtering. This is possible since the hyperbolic dispersion allows the vacuum
radiation to couple with medium plane waves with longitudinal wavenumbers large
enough to yield optical standing waves within the nanometric slab thickness.
Our findings can form the basis of a novel way for shrinking optical devices
down to the deep subwavelength scale.",1109.5101v1
2011-11-17,Resonance instability of axially-symmetric magnetostatic equilibria,"We review the evidence for and against the possibility that a strong enough
poloidal field stabilizes an axisymmetric magnetostatic field configuration. We
show that there does exist a class of resonant MHD waves which produce
instability for any value of the ratio of poloidal and toroidal field strength.
We argue that recent investigations of the stability of mixed poloidal and
toroidal field configurations based on 3-d numerical simulations, can miss this
instability because of the very large azimuthal wave numbers involved and its
resonant character.",1111.4040v2
2012-01-04,Propagation characteristics of complementary split-ring resonators excited by internal cylindrical wave,"For a complementary split-ring resonators (CSRRs) etched on one screen of two
infinite and perfectly conducting plates under cylindrical plane wave
illumination, the transmission coefficients analysis were performed through
finite-difference time-domain simulations. For the single slot ring CSRR, two
transmission dips are observed for the direction parallel to aperture at
resonance whereas two enhanced transmission for the direction normal to the
aperture. For double slot ring CSRR, the transmission coefficients appear more
anisotropic. The results provided considerable insight into the electromagnetic
response of CSRR and would be very helpful for developing new electronic
devices such as filters.",1201.1254v2
2012-03-21,Sharp tunneling peaks in a parametric oscillator: quantum resonances missing in the rotating wave approximation,"We describe a new mechanism of tunneling between period-two vibrational
states of a weakly nonlinear parametrically modulated oscillator. The tunneling
results from resonant transitions induced by the fast oscillating terms
conventionally disregarded in the rotating wave approximation (RWA). The
tunneling amplitude displays resonant peaks as a function of the modulation
frequency; near the maxima it is exponentially larger than the RWA tunneling
amplitude.",1203.4803v1
2012-08-13,Multichannel parametrization of πN scattering amplitudes and extraction of resonance parameters,"We present results of a new multichannel partial-wave analysis for \pi N
scattering in the c.m. energy range 1080 to 2100 MeV. This work explicitly
includes \eta N and K \Lambda channels and the single pion photoproduction
channel. Resonance parameters were extracted by fitting partial-wave amplitudes
from all considered channels using a multichannel parametrization that is
consistent with S-matrix unitarity. The resonance parameters so obtained are
compared to predictions of quark models.",1208.2710v2
2013-05-20,Multichannel parametrization of $\bar K N$ scattering amplitudes and extraction of resonance parameters,"We present results of a new multichannel partial-wave analysis for $\bar K N$
scattering in the c.m.\ energy range 1480 to 2100 MeV. Resonance parameters
were extracted by fitting partial-wave amplitudes from all considered channels
using a multichannel parametrization that is consistent with $S$-matrix
unitarity. The resonance parameters are generally in good agreement with
predictions of the Koniuk-Isgur quark model.",1305.4575v2
2013-09-25,"Self-organization, Pattern Formation, Cavity Solitons and Rogue Waves in Singly Resonant Optical Parametric Oscillators","Spatio-temporal dynamics of singly resonant optical parametric oscillators
with external seeding displays hexagonal, roll and honeycomb patterns, optical
turbulence, rogue waves and cavity solitons. We derive appropriate mean-field
equations with a sinc$^2$ nonlinearity and demonstrate that off-resonance
seeding is necessary and responsible for the formation of complex spatial
structures via self-organization. We compare this model with those derived
close to the threshold of signal generation and find that back-conversion of
signal and idler photons is responsible for multiple regions of spatio-temporal
self-organization when increasing the power of the pump field.",1309.6543v1
2014-01-05,Optical Rogue Waves in Whispering-Gallery-Mode Resonators,"We report a theoretical study showing that rogue waves can emerge in
whispering gallery mode resonators as the result of the chaotic interplay
between Kerr nonlinearity and anomalous group-velocity dispersion. The
nonlinear dynamics of the propagation of light in a whispering gallery-mode
resonator is investigated using the Lugiato-Lefever equation, and we evidence a
range of parameters where rare and extreme events associated with a
non-gaussian statistics of the field maxima are observed.",1401.0924v1
2014-01-18,"Semitransparent One Dimensional Potential, A Green's Function Approach","We study the unstable harmonic oscillator and the unstable linear potential
in the presence of the point potential, which is the superposition of the Dirac
$\delta(x)$ and the derivative $\delta'(x)$. Using the \textit{physical}
boundary conditions for the Green's function we derive for both systems the
resonance poles and the resonance wave functions. The matching conditions for
the resonance wave functions coincide with those obtained by the self-adjoint
extensions of the point potentials and also by the modelling of the
$\delta'(x)$. We find that, with our definitions, the pure $b\delta'(x)$
barrier is semi-transparent \textit{independent} of the value of $b$.",1401.4588v2
2014-03-22,Poisson wave trace formula for perturbed Dirac operators,"We consider self-adjoint Dirac operators $\ham{D}=\ham{D}_0 + V(x)$, where
$\ham{D}_0$ is the free three-dimensional Dirac operator and $V(x)$ is a smooth
compactly supported Hermitian matrix. We define resonances of $\ham{D}$ as
poles of the meromorphic continuation of its cut-off resolvent. An upper bound
on the number of resonances in disks, an estimate on the scattering determinant
and the Lifshits-Krein trace formula then leads to a global Poisson wave trace
formula for resonances of $\ham{D}$.",1403.5654v1
2014-04-13,Stable radiating gap solitons and their resonant interactions with dispersive waves in systems with parametric pump,"We study the formation of gap solitons in the presence of parametric pump. It
is shown that parametric pump can stabilize stationary solitons continuously
emitting dispersive waves. The resonant interactions of the radiation and the
solitons are studied and it is shown that the solitons can be effectively
controlled by the radiation. In particular it is shown that the solitons can
collide or to get pinned to inhomogeneities due to the interactions mediated by
the resonant radiation.",1404.3432v1
2014-11-11,Giant non-equilibrium vacuum friction: Role of singular evanescent wave resonances in moving media,"We recently reported on the existence of a singular resonance in moving media
which arises due to perfect amplitude and phase balance of evanescent waves. We
show here that the non-equilibrium vacuum friction (lateral Casimir-Lifshitz
force) between moving plates separated by a finite gap is fundamentally
dominated by this resonance. Our result is robust to losses and dispersion as
well as polarization mixing which occurs in the relativistic limit.",1411.2737v1
2015-01-23,Time-bin entangled photon pair generation from Si micro-ring resonator,"We demonstrate time-bin entanglement generation in telecom wavelength using a
7 {\mu}m radius Si micro-ring resonator pumped by a continuous wave laser. The
resonator structure can enhance spontaneous four wave mixing, leading to a
photon pair generation rate of about 90-100 Hz with a laser pump power of as
low as -3.92 dBm (0.41 mW). We succeed in observing time-bin entanglement with
the visibility over 92%. Moreover, wavelength-tunability of the entangled
photon pair is demonstrated by changing the operation temperature.",1501.05687v1
2015-01-28,Optical resonators based on Bloch surface waves,"A few recent works suggest the possibility of controlling light propagation
at the interface of periodic multilayers supporting Bloch surface waves (BSWs),
but optical resonators based on BSWs are yet to demonstrate. Here we discuss
the feasibility of exploiting guided BSWs in a ring resonator configuration. In
particular, we investigate the main issues related to the design of these
structures, and we discuss about their limitations in terms of quality factors
and dimensions. We believe these results might be useful for the development of
a complete BSW-based platform for application ranging from optical sensing to
the study of the light-matter interaction in micro and nano structures.",1501.07025v1
2015-03-12,Scalar Resonances in Axially Symmetric Spacetimes,"We study properties of resonant solutions to the scalar wave equation in
several axially symmetric spacetimes. We prove that non-axial resonant modes do
not exist neither in the Lanczos dust cylinder, the $(2+1)$ extreme BTZ
spacetime nor in a class of simple rotating wormhole solutions. Moreover, we
find unstable solutions to the wave equation in the Lanczos dust cylinder and
in the $r^2 <0$ region of the extreme $(2+1)$ BTZ spacetime, two solutions that
possess closed timelike curves. Similarities with previous results obtained for
the Kerr spacetime are explored.",1503.03755v1
2018-11-05,Surface acoustic wave coupled to magnetic resonance on a multiferroic CuB$_2$O$_4$,"We observed surface acoustic wave (SAW) propagation on a multiferroic
material CuB$_2$O$_4$ with use of two interdigital transducers (IDTs). The
period of IDT fingers is as short as 1.6 $\mu$m so that the frequency of SAW is
3 GHz, which is comparable with that of magnetic resonance. In
antiferromagnetic phase, the SAW excitation intensity varied with the magnitude
and direction of the magnetic field, owing to the dynamical coupling between
SAWs and antiferromagnetic resonance of CuB$_2$O$_4$. The microscopic mechanism
is discussed based on the symmetrically allowed magentoelastic coupling.",1811.01527v1
2016-03-13,Minnaert resonances for acoustic waves in bubbly media,"Through the application of layer potential techniques and Gohberg-Sigal
theory we derive an original formula for the Minnaert resonance frequencies of
arbitrarily shaped bubbles. We also provide a mathematical justification for
the monopole approximation of scattering of acoustic waves by bubbles at their
Minnaert resonant frequency. Our results are complemented by several numerical
examples which serve to validate our formula in two dimensions.",1603.03982v1
2018-04-16,Analysis of surface polariton resonance for nanoparticles in elastic system,"This paper is concerned with the analysis of surface polariton resonance for
nanoparticles in linear elasticity. With the presence of nanoparticles, we
first derive the perturbed displacement field associated to a given elastic
source field. It is shown that the leading-order term of the perturbed elastic
wave field is determined by the Neumann-Poinc\'are operator associated to the
Lam\'e system. By analyzing the spectral properties of the aforesaid
Neumann-Poinc\'are operator, we study the polariton resonance for the elastic
system. The results may find applications in elastic wave imaging.",1804.05480v1
2008-06-17,Input Impedance and Gain of a Gigahertz Amplifier Using a DC SQUID in a Quarter Wave Resonator,"Due to their superior noise performance, SQUIDs are an attractive alternative
to high electron mobility transistors for constructing ultra-low-noise
microwave amplifiers for cryogenic use. We describe the use of a lumped element
SQUID inductively coupled to a quarter wave resonator. The resonator acts as an
impedance transformer and also makes it possible for the first time to
accurately measure the input impedance and intrinsic microwave characteristics
of the SQUID. We present a model for input impedance and gain, compare it to
the measured scattering parameters, and describe how to use the model for the
systematic design of low-noise microwave amplifiers with a wide range of
performance characteristics.",0806.2853v1
2020-02-02,Resonant amplified seismic response within a hill or mountain,"We show theoretically what is meant by the term '(surface shape) resonance'
in connection with the seismic response of a protuberance (emerging from flat
ground) such as a hill or mountain of arbitrary shape. We address the specific
problem of cylindrical protuberances of rectangular shape submitted to a SH
plane wave. We find that the principal (i.e., qualitative) characteristics of
the seismic response of a mountain are quite similar to those of a hill, and
that the occurrence of significative amplification of the displacement field
within these structures is due to the coupling of the incident wave to (surface
shape) resonances.",2002.00389v1
2020-07-21,A Hybrid (Al)GaAs-LiNbO$_3$ Surface Acoustic Wave Resonator for Cavity Quantum Dot Optomechanics,"A hybrid device comprising a (Al)GaAs quantum dot heterostructure and a
LiNbO$_3$ surface acoustic wave resonator is fabricated by heterointegration.
High acoustic quality factors $Q>4000$ are demonstrated for an operation
frequency $f\approx 300$ MHz. The measured large quality factor-frequency
products $Q\times f>10^{12}$ ensures the suppression of decoherence due to
thermal noise for temperatures exceeding $T>50\,\mathrm{K}$. Frequency and
position dependent optomechanical coupling of single quantum dots and the
resonator modes is observed.",2007.11082v2
2022-01-24,Scattering For three waves Nonlinear Schrödinger System with mass-resonance in 5D,"In this paper, we study the dynamics behavior of the NLS system with three
waves interaction in the energy space $H^1(\mathbb{R}^5) \times
H^1(\mathbb{R}^5)\times H^1(\mathbb{R}^5) $. Inspired by B. Dodson and J.
Murphy in \cite{Dodson2018}, we establish an interaction Morawetz estimate for
the NLS system, together with the criterion which proved by Tao-Dodson--Murphy
we can get the scattering under the ground state in energy space with
mass-resonance. Under the radial assumption, we can remove the mass-resonance
condition.",2201.09408v1
2022-09-12,Minimally-diffracting quartz for ultra-low temperature surface acoustic wave resonators,"We simulate and experimentally demonstrate the existence of an orientation of
quartz which minimizes diffraction losses in surface acoustic wave (SAW)
resonators at ultra-low temperatures. The orientation is optimized for
applications to quantum technologies which benefit from high mechanical quality
factors, strong electromechanical coupling, and narrow acoustic apertures. We
fabricate narrow aperture SAW resonators on this substrate and measure internal
quality factors greater than 100,000 at mK temperatures.",2209.05501v1
2023-07-08,Coupling high-overtone bulk acoustic wave resonators via superconducting qubits,"In this work, we present a device consisting of two coupled transmon qubits,
each of which are coupled to an independent high-overtone bulk acoustic wave
resonator (HBAR). Both HBAR resonators support a plethora of acoustic modes,
which can couple to the qubit near resonantly. We first show qubit-qubit
interaction in the multimode system, and finally quantum state transfer where
an excitation is swapped from an HBAR mode of one qubit, to an HBAR mode of the
other qubit.",2307.05544v1
2023-08-03,Complete mode conversion for elastic waves reflected by elastic metamaterial slab with double hexapole resonances,"In this study, we investigate the phenomenon of mode conversion in elastic
bulk waves using coupled hexapole resonances. A metamaterial slab is proposed
enabling the complete conversion between longitudinal and transverse modes.
Each unit of the elastic metamaterial slab comprises a pair of scatterers, and
their relative direction is oriented at an oblique angle. The interaction
between the coupled hexapoles and the background results in oblique
displacements, which are responsible for the mode conversion. Moreover, this
conversion exhibits a broader frequency range compared to the quadrupole
resonance. This innovative design significantly broadens the range of
possibilities for developing mode-converting metamaterials.",2308.01969v1
2023-10-07,Wave scattering by objects made of small particles with pulsating permittivity,"In this work we study the wave scattering by small dispersionless particles
with pulsating refractive index. The scattered fields and their resonance
frequencies are calculated by using scalar approximation and exponentially
time-dependent permittivity.
  In addition, the scattering by single sphere with the pulsating permittivity
is calculated numerically for different regimes of the pulsations.
  Our results suggest that the pulsations of the refractive index of the
scatterer significantly affect the scattered field: existing resonances shift,
additional resonances emerge, and deeps in the light scattering spectrum
appear.",2310.04798v2
2023-12-21,Scattering results for the (1+4) dimensional massive Maxwell-Dirac system under Lorenz gauge condition,"This paper investigates the \emph{massive} Maxwell-Dirac system under the
Lorenz gauge condition in (4+1) dimensional Minkowski space. The focus is on
establishing global existence and scattering results for small solutions on the
weighted Sobolev class. The imposition of the Lorenz gauge condition transforms
the Maxwell-Dirac system into a set of Dirac equations coupled with an
electromagnetic potential derived from five quadratic wave equations. To
achieve a comprehensive understanding of the global solution and its behavior,
we employ various energy estimates based on the space-time resonance argument.
This involves addressing diverse resonance functions arising from the free
Dirac and wave propagators. Additionally, we identify the space-time resonant
sets associated with the \emph{massive} Maxwell-Dirac system.",2312.13621v1
2014-03-24,Spin wave imaging in atomically designed nanomagnets,"The spin dynamics of all ferromagnetic materials are governed by two types of
collective excitations: spin waves and domain walls. The fundamental processes
underlying these collective modes, such as exchange interactions and magnetic
anisotropy, all originate at the atomic scale; yet, conventional probing
techniques, based on neutron and photon scattering, provide high resolution in
reciprocal space, and thereby poor spatial resolution. Here we present direct
imaging of spin waves in individual chains of ferromagnetically coupled $S=2$
Fe atoms, assembled one by one on a Cu$_2$N surface using a scanning tunnelling
microscope. We are able to map the spin dynamics of these designer nanomagnets
with atomic resolution, in two complementary ways. First, atom to atom
variations of the amplitude of the quantized spin wave excitations, predicted
by theory, are probed using inelastic electron tunnelling spectroscopy. Second,
we observe slow stochastic switching between two opposite magnetisation states,
whose rate varies strongly depending on the location of the tip along the
chain. Our observations, combined with model calculations, reveal that switches
of the chain are initiated by a spin wave excited state which has its antinodes
at the edges of the chain, followed by a domain wall shifting through the chain
from one end to the other. This approach opens the way towards atomic scale
imaging of other types of spin excitations, such as spinons and fractional
end-states, in engineered spin chains.",1403.5890v1
2022-10-19,Improving the spin-down limits of the continuous gravitational waves emitted from rotating triaxial pulsars,"The spin-down limit of the continuous gravitational wave strain from pulsars
assumed to be triaxial stars rotating about a principal moment of inertia axis
depends upon the value of the intrinsic spin frequency derivative of the
pulsar, among other parameters. In order to get more accurate intrinsic spin
frequency derivative values, dynamical effects contributing to the measured
spin frequency derivative values must be estimated via more realistic
approaches. In this work, we calculated improved values for the spin-down limit
of the continuous gravitational wave strain (assuming that pulsars are triaxial
stars rotating about a principal moment of inertia axis) for a set of 237
pulsars for which a targeted search for continuous gravitational waves was
recently carried out by the LIGO-Virgo-KAGRA (LVK) Collaboration. We used
`GalDynPsr', a Python-based public package, to calculate more realistic values
for the intrinsic spin frequency derivatives and, consequently, we get more
realistic values of the spin-down limit. The realistic values that we obtain
for the intrinsic spin frequency derivatives can also provide a valuable
contribution to improving the sensitivity of searches for continuous
gravitational waves from known pulsars.",2210.10355v2
2022-08-29,On Tsunami Waves induced by Atmospheric Pressure Shock Waves after the 2022 Hunga Tonga-Hunga Ha'apai Volcano Eruption,"Employing a linear shallow water equation (LSWE) model in the spherical
coordinates, this paper investigates the tsunami waves generated by the
atmospheric pressure shock waves due to the explosion of the submarine volcano
Hunga Tonga-Hunga Ha'apai on January 15, 2022. Using the selected 59
atmospheric pressure records in the Pacific Ocean, an empirical atmospheric
pressure model is first constructed. Applying the atmospheric pressure model
and realistic bathymetric data in the LSWE model, tsunami generation and
propagation are simulated in the Pacific Ocean. The numerical results show
clearly the co-existence of the leading locked waves, propagating with the
speed of the atmospheric pressure waves (~1,100 km/hr), and the trailing free
waves, propagating with long gravity ocean wave celerity (~ 750 km/hr). During
the event, tsunamis were reported by 41 DART buoys in the Pacific Ocean, which
require corrections because of the occurrence of atmospheric pressure waves.
The numerically simulated tsunami arrival time and the amplitudes of the wave
crest and trough of the leading locked waves compare reasonably well with the
corrected DART measurements. The comparisons for the trailing waves are less
satisfactory, since free waves could also have been generated by other tsunami
generation mechanisms, which have not been considered in the present model, and
by the scattering of locked waves over changing bathymetry. In this regard, the
numerical results show clearly that the deep Tonga trench (~ 10 km) amplifies
the trailing waves in the Southeast part of the Pacific Ocean via the Proudman
resonance condition.",2208.13473v1
2023-06-08,Series Solution for Interaction of Scalar Plane Wave with Spatially Decaying Gravitational Wave,"In this paper we present the power series solution of the Klein-Gordon
equation in the spacetime background of a gravitational wave with amplitude
that decays with distance from the source. The resulting solution describes the
interaction of a scalar plane wave travelling in an arbitrary direction
relative to the direction of propagation of the gravitational wave. This
solution has the unexpected property that as the scalar wave approaches
collinearity with the gravitational wave there is a rapid transition in the
form of the solution. The solution in the collinear limit exhibits a resonance
phenomenon which distinguishes these results from previous analyses involving
plane gravitational wave backgrounds. We discuss in detail the similarities and
differences between the solutions for plane gravitational waves and
gravitational waves with amplitude that decreases with distance from the
source. We give an argument that this solution of the Klein-Gordon equation
only describes the interaction of a gravitational wave with a scalar wave and
that the gravitational wave will not produce a scalar waveform in a vacuum. The
interaction between the gravitational and scalar waves lead to both sinusoidal
time-dependent fluctuations in, and time-independent enhancement of, the scalar
current in the direction of the gravitational wave. Finally, we discuss the
possibility of observable effects of this interaction.",2306.05394v1
1999-04-20,Birth of resonances in the spin-orbit problem of Celestial Mechanics,"The behaviour of resonances in the spin-orbit coupling in Celestial Mechanics
is investigated. We introduce a Hamiltonian nearly-integrable model describing
an approximation of the spin-orbit interaction. A parametric representation of
periodic orbits is presented. We provide explicit formulae to compute the
Taylor series expansion in the perturbing parameter of the function describing
this parametrization. Then we compute approximately the radius of convergence
providing an indication of the stability of the periodic orbit. This quantity
is used to describe the different probabilities of capture into resonance. In
particular, we notice that for low values of the orbital eccentricity the only
significative resonance is the synchronous one. Higher order resonances
(including 1:2, 3:2, 2:1) appear only as the orbital eccentricity is increased.",9904035v1
1997-10-14,Pi excitation of the t-J model,"In this paper, we present analytical and numerical calculations of the pi
resonance in the t-J model. We show in detail how the pi resonance in the
particle-particle channel couples to and appears in the dynamical spin
correlation function in a superconducting state. The contribution of the pi
resonance to the spin excitation spectrum can be estimated from general
model-independent sum rules, and it agrees with our detailed calculations. The
results are in overall agreement with the exact diagonalization studies of the
t-J model. Earlier calculations predicted the correct doping dependence of the
neutron resonance peak in the YBCO superconductor, and in this paper detailed
energy and momentum dependence of the spin correlation function is presented.
The microscopic equations of motion obtained within current formalism agree
with that of the SO(5) nonlinear sigma model, where the pi resonance is
interpreted as a pseudo Goldstone mode of the spontaneous SO(5) symmetry
breaking.",9710139v1
2001-11-29,Zeeman effects on the impurity-induced resonances in d-wave superconductors,"It is shown how the resonant states induced by a single spinless impurity in
a d-wave superconductor evolve under the effect of an applied Zeeman magnetic
field. Moreover, it is demonstrated that the spin-orbit coupling to the
impurity potential can have important and characteristic effects on the
resonant states and their response to the Zeeman field, especially when the
impurity is close to the unitary limit. For zero or very small spin-orbit
interaction, the resonant states becomes Zeeman splitted by the magnetic field
while when the spin-orbit coupling is important, new low-lying resonances arise
which do not show any Zeeman splitting.",0111554v2
2004-03-24,Resonant magnetic excitations at high energy in superconducting $\bf YBa_2Cu_3O_{6.85}$,"A detailed inelastic neutron scattering study of the high temperature
superconductor $\rm YBa_2Cu_3O_{6.85}$ provides evidence of new resonant
magnetic features, in addition to the well known resonant mode at 41 meV: (i) a
commensurate magnetic resonance peak at 53 meV with an even symmetry under
exchange of two adjacent $\rm CuO_2$ layers; and (ii) high energy
incommensurate resonant spin excitations whose spectral weight is around 54
meV. The locus and the spectral weight of these modes can be understood by
considering the momentum shape of the electron-hole spin-flip continuum of
d-wave superconductors. This provides new insight into the interplay between
collective spin excitations and the continuum of electron-hole excitations.",0403609v1
2011-04-02,Vector meson-Baryon dynamics and generation of resonances,"The purpose of this work is to study vector meson-octet baryon interactions
with the aim to find dynamical generation of resonances in such systems. For
this, we consider s-, t-, u-channel diagrams along with a contact interaction
originating from the hidden local symmetry Lagrangian. We find the contribution
from all these sources, except the s-channel, to be important. The amplitudes
obtained by solving coupled channel Bethe Salpeter equations for systems with
total strangeness zero, show generation of one isospin 3/2, spin 1/2 resonance
and three isospin 1/2 resonances: two with spin 3/2 and one with spin 1/2. We
identify these resonances with $\Delta (1900) S_{31}$, $N^* (2080) D_{13}$,
$N^* (1700) D_{13}$, and $N^*(2090) S_{11}$, respectively.",1104.0307v1
2011-09-10,Entanglement Evolution via Quantum Resonances,"We consider two qubits interacting with local and collective thermal
reservoirs. Each spin-reservoir interaction consists of an energy exchange and
an energy conserving channel. We prove a resonance representation of the
reduced dynamics of the spins, valid for all times t>=0, with errors (small
interaction) estimated rigorously, uniformly in time. Subspaces associated to
non-interacting energy differences evolve independently, partitioning the
reduced density matrix into dynamically decoupled clusters of jointly evolving
matrix elements. Within each subspace the dynamics is markovian with a
generator determined entirely by the resonance data of the full Hamiltonian.
Based on the resonance representation we examine the evolution of entanglement
(concurrence). We show that, whenever thermalization takes place, entanglement
of any initial state dies out in a finite time and will not return. For a
concrete class of initially entangled spin states we find explicit bounds on
entanglement survival and death times in terms of the initial state and the
resonance data.",1109.2235v1
2013-06-18,The confinement induced resonance in spin-orbit coupled cold atoms with Raman coupling,"We investigate the confinement induced resonance in spin-orbit coupled cold
atoms with Raman coupling. We find that the quasi-bound levels induced by the
spin-orbit coupling and Raman coupling result in the Feshbach-type resonances.
For sufficiently large Raman coupling, the bound states in one dimension exist
only for sufficiently strong attractive interaction. Furthermore, the bound
states in quasi-one dimension exist only for sufficient large ratio of the
length scale of confinement to three dimensional s-wave scattering length. The
Raman coupling substantially changes the confinement-induced resonance
position. We give a proposal to realize confinement induced resonance by
increasing the Raman coupling strength in experiments.",1306.4099v5
2013-10-09,Spin resonance in AFe2Se2 with s-wave pairing symmetry,"We study spin resonance in the superconducting state of recently discovered
alkali-intercalated iron selenide materials A_xFe_(2-y)Se_2 (A=K,Rb,Cs) in
which the Fermi surface has only electron pockets. Recent angle-resolved
photoemission spectroscopy (ARPES) studies [M. Xu et al., Phys. Rev. B 85,
220504(R) (2012)] were interpreted as strong evidence for s-wave gap in these
materials, while the observation of the resonance peak in neutron scattering
measurements [G. Friemel et al., Phys. Rev. B 85, 140511 (2012)] suggests that
the gap must have different signs at Fermi surface points connected by the
momentum at which the resonance has been observed. We consider recently
proposed unconventional s+- superconducting state of A_xFe_(2-y)Se_2 with
superconducting gap changing sign between the hybridized electron pockets. We
argue that such a state supports a spin resonance. We compute the dynamical
structure factor and show that it is consistent with the results of inelastic
neutron scattering.",1310.2334v2
2015-07-27,Electron spin resonance in a model S=1/2 chain antiferromagnet with a uniform Dzyaloshinskii--Moriya interaction,"The electron spin resonance spectrum of a quasi 1D S=1/2 antiferromagnet
K2CuSO4Br2 was found to demonstrate an energy gap and a doublet of resonance
lines in a wide temperature range between the Curie--Weiss and Ne\`{e}l
temperatures. This type of magnetic resonance absorption corresponds well to
the two-spinon continuum of excitations in S=1/2 antiferromagnetic spin chain
with a uniform Dzyaloshinskii--Moriya interaction between the magnetic ions. A
resonance mode of paramagnetic defects demonstrating strongly anisotropic
behavior due to interaction with spinon excitations in the main matrix is also
observed.",1507.07518v1
2016-07-27,The Role of Multilevel Landau-Zener Interference in Extreme Harmonic Generation,"Motivated by the observation of multiphoton electric dipole spin resonance
processes in InAs nanowires, we theoretically study the transport dynamics of a
periodically driven five-level system, modeling the level structure of a
two-electron double quantum dot. We show that the observed multiphoton
resonances, which are dominant near interdot charge transitions, are due to
multilevel Landau-Zener-Stuckelberg-Majorana interference. Here a third energy
level serves as a shuttle that transfers population between the two resonant
spin states. By numerically integrating the master equation we replicate the
main features observed in the experiments: multiphoton resonances (as large as
8 photons), a robust odd-even dependence, and oscillations in the electric
dipole spin resonance signal as a function of energy level detuning.",1607.08207v1
2017-07-04,High-Resolution Nanoscale Solid-State Nuclear Magnetic Resonance Spectroscopy,"We present a new method for high-resolution nanoscale magnetic resonance
imaging (nano-MRI) that combines the high spin sensitivity of nanowire-based
magnetic resonance detection with high spectral resolution nuclear magnetic
resonance (NMR) spectroscopy. By applying NMR pulses designed using optimal
control theory, we demonstrate a factor of $500$ reduction of the proton spin
resonance linewidth in a $(50\text{-nm})^{\text{3}}$ volume of polystyrene and
image proton spins in one dimension with a spatial resolution below
$2~\text{nm}$.",1707.01062v1
2019-11-26,Ultrastrong coupling between a microwave resonator and antiferromagnetic resonances of rare earth ion spins,"Quantum magnonics is a new and active research field, leveraging the strong
collective coupling between microwaves and magnetically ordered spin systems.
To date work in quantum magnonics has focused on transition metals and almost
entirely on ferromagnetic resonances in yttrium iron garnet (YIG).
Antiferromagnetic systems have gained interest as they produce no stray field,
and are therefore robust to magnetic perturbations and have narrow, shape
independent resonant linewidths. Here we show the first experimental evidence
of ultrastrong-coupling between a microwave cavity and collective
antiferromagnetic resonances (magnons) in a rare earth crystal. The combination
of the unique optical and spin properties of the rare earths and collective
antiferromagnetic order paves the way for novel quantum magnonic applications.",1911.11311v1
2018-04-01,Resonance states near a quantum magnetic impurity in single-layer FeSe superconductors with $d$-wave symmetry,"In this work, we investigate the local density of states (LDOS) near a
magnetic impurity in single-layer FeSe superconductors. The two-orbital model
with spin-orbit coupling proposed in Ref. [{\emph{Phys. Rev. Lett.}
\textbf{119}, 267001 (2017)}] is used to describe the FeSe superconductor. In
the strong coupling regime, two impurity resonance peaks appear with opposite
resonance energies in the LDOS spectral function. For a strong spin-orbit
coupling, the superconducting gap in this model is $d$-wave symmetric with
nodes, the spatial distributions of the LDOS at the two resonance energies are
fourfold symmetric, which reveals typical characteristic of $d$-wave pairing.
When the spin-orbit coupling is not strong enough to close the superconducting
gap, we find that the spatial distribution of the LDOS at one of the resonance
energies manifests $s$-wave symmetry, while the pairing potential preserves
$d$-wave symmetry. This result is consistent with previous experimental
investigations.",1804.00258v1
2020-02-11,Revisiting the Possible 4f7 5d1 Ground State of Gd Impurities in SmB6 by Electron Spin Resonance,"The search for topological states in strongly correlated electron systems has
renewed the interest in the Kondo insulator SmB6. One of the most intriguing
previous results was an anomalous electron spin resonance spectrum in Gd-doped
SmB6. This spectrum was attributed to Gd2+ ions because it could be very well
decribed by a model considering a change in the valence from Gd3+ to Gd2+, a
dynamic Jahn-Teller effect and a 4f7 5d1 ground state in the Hamiltonian. In
our work, we have revisited this scenario using electron spin resonance and
energy dispersive X-ray spectroscopy measurements. Our results suggest that the
resonance is produced by Gd2+ ions; however the resonance stems from an
extrinsic oxide impurity phase that lies on the surface of the crystal.",2002.04572v1
2020-07-28,Dynamical Zeeman resonance in spin-orbit-coupled spin-1 Bose gases,"We predict a dynamical resonant effect, which is driven by externally applied
linear and quadratic Zeeman fields, in a spin-orbit-coupled spin-1
Bose-Einstein condensate. The Bose-Einstein condensate is assumed to be
initialized in some superposed state of Zeeman sublevels and subject to a
sudden shift of the trapping potential. It is shown that the time-averaged
center-of-mass oscillation and the spin polarizations of the Bose-Einstein
condensate exhibit remarkable resonant peaks when the Zeeman fields are tuned
to certain strengths. The underlying physics behind this resonance can be
traced back to the out-of-phase interference of the dynamical phases carried by
different spinorbit states. By analyzing the single particle spectrum, the
resonant condition is summarized as a simple algebraic relation, connecting the
strengths of the linear and quadratic Zeeman fields. This property is
potentially applicable in quantum information and quantum precision
measurement.",2007.14131v1
2021-07-16,Influence of inter-sublattice coupling on the terahertz nutation spin dynamics in antiferromagnets,"Spin nutation resonance has been well-explored in one-sublattice
ferromagnets. Here, we investigate the spin nutation in two-sublattice
antiferromagnets as well as, for comparison, ferrimagnets with inter-and
intra-sublattice nutation coupling. In particular, we derive the susceptibility
of the two-sublattice magnetic system in response to an applied external
magnetic field. To this end, the antiferromagnetic and ferrimagnetic (sub-THz)
precession and THz nutation resonance frequencies are calculated. Our results
show that the precession resonance frequencies and effective damping decrease
with intra-sublattice nutation coupling, while they increase with inter
-sublattice nutation in an antiferromagnet. However, we find that the THz
nutation resonance frequencies decrease with both the intra-and
inter-sublattice nutation couplings. For ferrimagnets, conversely, we calculate
two nutation modes with distinct frequencies, unlike antiferromagnets. The
exchange-like precession resonance frequency of ferrimagnets decreases with
intra-sublattice nutation coupling and increases with inter-sublattice nutation
coupling, like antiferromagnets, but the ferromagnetic-like precession
frequency of ferrimagnets is practically invariant to the intra and
inter-sublattice nutation couplings.",2107.07939v2
2021-09-20,"Electron Spin Resonance of the itinerant ferromagnets LaCrGe3, CeCrGe3 and PrCrGe3","We report Electron Spin Resonance of the itinerant ferromagnets LaCrGe3,
CeCrGe3, and PrCrGe3. These compounds show well defined and very similar
spectra of itinerant Cr 3d spins in the paramagnetic temperature region. Upon
cooling and crossing the Cr-ferromagnetic ordering (below around 90 K) strong
spectral structures start to dominate the resonance spectra in a quite
different manner in the three compounds. In the Ce- and Pr-compounds the
resonance is only visible in the paramagnetic region whereas in the La-compound
the resonance can be followed far below the ferromagnetic ordering temperature.
This behavior will be discussed in terms of the specific interplay between the
4f and 3d magnetism which appears quite remarkable since CeCrGe3 displays heavy
fermion behavior even in the magnetically ordered state.",2109.09341v1
2022-05-09,Coupling Spin Defects in Hexagonal Boron Nitride to Titanium Oxide Ring Resonators,"Spin-dependent optical transitions are attractive for a plethora of
applications in quantum technologies. Here we report on utilization of high
quality ring resonators fabricated from TiO2 to enhance the emission from
negatively charged boron vacancies in hexagonal Boron Nitride. We show that the
emission from these defects can efficiently couple into the whispering gallery
modes of the ring resonators. Optically coupled boron vacancy showed
photoluminescence contrast in optically detected magnetic resonance signals
from the hybrid coupled devices. Our results demonstrate a practical method for
integration of spin defects in 2D materials with dielectric resonators which is
a promising platform for quantum technologies.",2205.04031v1
2023-12-19,Three-photon electron spin resonances,"We report the observation of a three-photon resonant transition of
charge-carrier spins in an organic light-emitting diode using electrically
detected magnetic resonance (EDMR) spectroscopy at room temperature. Under
strong magnetic-resonant drive (drive field $B_1$ ~ static magnetic field
$B_0$), a $B_0$-field swept EDMR line emerges when $B_0$ is approximately
threefold the one-photon resonance field. Ratios of drive-induced shifts of
this line to those of two- and one-photon shifts agree with analytical
expressions derived from the Floquet Hamiltonian and confirm the nature of
these three-photon transitions, enabling access of spin physics to a hitherto
inaccessible domain of quantum mechanics.",2312.12609v1
2002-12-19,Trapped particle bounds on stimulated scatter in the large k/kD regime,"In the strongly damped regime, the convective gain rate for stimulated
scatter varies inversely with the plasma wave damping rate. Electron trapping
effects reduce the damping but also lead to loss of resonance for large enough
amplitude waves. This leads to a gain rate bound and corresponding optimum
scattered light frequency and plasma wave amplitude.",0212071v1
2006-05-02,Enhanced transmission of light through a gold film due to excitation of standing surface plasmon Bloch waves,"We have observed enhanced transmission of light through a gold film due to
excitation of standing surface plasmon Bloch waves in a surface Fabry-Perot
resonator. Our experimental results strongly contradict the recently suggested
model of light transmission via excitation of a composite diffractive
evanescent wave.",0605020v1
2005-01-19,Einstein's coefficients and the wave-particle duality in the theory of thermal radiation,"It is shown that the concept of elementary resonator in the theory of thermal
radiation implies the indivisible connection between particles (photons) and
electromagnetic waves. This wave-particle duality covers both the Wien and
Rayleigh-Jeans regions of spectrum.",0501103v1
2014-04-17,Tuning resonant interaction of orthogonally polarized solitons and dispersive waves with the soliton power,"We demonstrate that the relatively small power induced changes in the soliton
wavenumber comparable with splitting of the effective indexes of the
orthogonally polarized waveguide modes result in significant changes of the
efficiency of the interaction between solitons and dispersive waves and can be
used to control energy transfer between the soliton and newly generated waves
and to delay or accelerate solitons.",1404.4476v1
2021-10-04,Asymptotic stability of solitary waves for the 1D cubic-quintic Schrödinger equation with no internal mode,"For the Schr\""odinger equation with a cubic-quintic, focusing-defocusing
nonlinearity in one space dimension, we prove the asymptotic stability of
solitary waves for a large range of admissible frequencies. For this model, the
linearized problem around the solitary waves does not have internal mode nor
resonance.",2110.01492v1
2021-10-18,Zeroth-order considerations on an accelerator-based gravitational wave amplifier,"The operation of an accelerator-based gravitational wave amplifier has been
studied, taking into account the interaction between beam and gravitational
wave and neglecting all effects related to the emission of - and interaction
with electromagnetic radiation. The small-gain operation mode has been
considered. The gravitational counterpart of the Madey theorem as well some
basic amplifier quantities as resonance wavelength, amplifier gain and gain
length have been derived.",2110.09025v1
2022-07-08,Unconventional Collective Resonance as Nonlinear Mechanism of Ectopic Activity in Excitable Media,"Many physical, chemical and biological processes rely on intrinsic
oscillations to employ resonance responses to external stimuli of certain
frequency. Such resonance phenomena in biological systems are typically
explained by one of two mechanisms: either a classical linear resonance of
harmonic oscillator, or entrainment and phase locking of nonlinear limit cycle
oscillators subjected to periodic forcing. Here, we discover a nonlinear
mechanism, which does not require intrinsic oscillations. Instead, the resonant
frequency dependence arises from coupling between an excitable and a monostable
region of the medium. This composite system is endowed with emergent
bistability between a stable steady state and stable spatiotemporal
oscillations. The resonant transition from stable state to oscillatory state is
induced by waves of particular frequency travelling through the medium. This
transition to the spatiotemporal oscillatory state requires accumulation of
multiple waves, resulting in the exclusion of lower frequencies. The cutting
off of high frequencies is realized by damping of wave amplitude in the
monostable zone and then by activating amplitude sensitive dynamics in the
monostable units. We demonstrate this new resonance mechanism in a simplistic
reaction-diffusion model. Also, we reveal this collective resonance mechanism
in in-vitro experiments and detailed biophysical simulations representing a
major type of arrhythmia. We further demonstrate, both experimentally and
theoretically, that the ongoing spatiotemporal oscillations, such as ectopic
activity in cardiac tissue, can be stopped by travelling waves of high
frequency. Overall, we claim the universality of this resonance mechanism in a
broad class of nonlinear biophysical systems. Specifically, we hypothesize that
such phenomena could be found in neuronal systems as an alternative to
traditional resonant processes.",2207.03975v1
2020-10-05,Floquet spin states in OLEDs,"Weakly spin-orbit coupled electron and hole spins in organic light-emitting
diodes (OLEDs) constitute near-perfect two-level systems to explore the
interaction of light and matter in the ultrastrong-drive regime. Under such
highly non-perturbative conditions, the frequency at which the spin oscillates
between states, the Rabi frequency, becomes comparable to its natural resonance
frequency, the Larmor frequency. For such conditions, we develop an intuitive
understanding of the emergence of hybrid light-matter states, illustrating how
dipole-forbidden multiple-quantum transitions at integer and fractional
g-factors arise. A rigorous theoretical treatment of the phenomena comes from a
Floquet-style solution to the time-dependent Hamiltonian of the electron-hole
spin pair under resonant drive. To probe these phenomena experimentally
requires both the development of a magnetic-resonance setup capable of
supporting oscillating driving fields comparable in magnitude to the static
field defining the Zeeman splitting; and an organic semiconductor which is
characterized by minimal inhomogeneous broadening so as to allow the non-linear
light-matter interactions to be resolved. The predicted exotic resonance
features associated with the Floquet states are indeed found experimentally in
measurements of spin-dependent steady-state OLED current under resonant drive,
demonstrating that complex hybrid light-matter spin excitations can be formed
and probed at room temperature. The spin-Dicke state arising under strong drive
is insensitive to power broadening so that the Bloch-Siegert shift of the
resonance becomes apparent, implying long coherence times of the dressed spin
state with potential applicability for quantum sensing.",2010.02170v1
2007-05-24,Optical investigations of quantum-dot spin dynamics,"We have performed all-optical measurements of spin relaxation in single
self-assembled InAs/GaAs quantum dots (QD) as a function of static external
electric and magnetic fields. To study QD spin dynamics we measure the degree
of resonant absorption which results from a competition between optical spin
pumping induced by the resonant laser field and spin relaxation induced by
reservoirs. Fundamental interactions that determine spin dynamics in QDs are
hyperfine coupling to QD nuclear spin ensembles, spin-phonon coupling and
exchange-type interactions with a nearby Fermi sea of electrons. We show that
the strength of spin relaxation generated by the three fundamental interactions
can be changed by up to five orders of magnitude upon varying the applied
electric and magnetic fields. We find that the strength of optical spin pumping
that we use to study the spin relaxation is determined predominantly by
hyperfine-induced mixing of single-electron spin states at low magnetic fields
and heavy-light hole mixing at high magnetic fields. Our measurements allow us
to determine the rms value of the hyperfine (Overhauser) field to be ~15 mTesla
with an electron g-factor of g_e=0.6 and a hole mixing strength of |epsilon|^2
= 0.0005.",0705.3557v1
2010-01-20,Spin electric effects in molecular antiferromagnets,"Molecular nanomagnets show clear signatures of coherent behavior and have a
wide variety of effective low-energy spin Hamiltonians suitable for encoding
qubits and implementing spin-based quantum information processing. At the
nanoscale, the preferred mechanism for control of quantum systems is through
application of electric fields, which are strong, can be locally applied, and
rapidly switched. In this work, we provide the theoretical tools for the search
for single molecule magnets suitable for electric control. By group-theoretical
symmetry analysis we find that the spin-electric coupling in triangular
molecules is governed by the modification of the exchange interaction, and is
possible even in the absence of spin-orbit coupling. In pentagonal molecules
the spin-electric coupling can exist only in the presence of spin-orbit
interaction. This kind of coupling is allowed for both $s=1/2$ and $s=3/2$
spins at the magnetic centers. Within the Hubbard model, we find a relation
between the spin-electric coupling and the properties of the chemical bonds in
a molecule, suggesting that the best candidates for strong spin-electric
coupling are molecules with nearly degenerate bond orbitals. We also
investigate the possible experimental signatures of spin-electric coupling in
nuclear magnetic resonance and electron spin resonance spectroscopy, as well as
in the thermodynamic measurements of magnetization, electric polarization, and
specific heat of the molecules.",1001.3584v1
2014-01-12,Sub-nanometer resolution in three-dimensional magnetic-resonance imaging of individual dark spins,"Magnetic resonance imaging (MRI) has revolutionized biomedical science by
providing non-invasive, three-dimensional biological imaging. However, spatial
resolution in conventional MRI systems is limited to tens of microns, which is
insufficient for imaging on molecular and atomic scales. Here we demonstrate an
MRI technique that provides sub-nanometer spatial resolution in three
dimensions, with single electron-spin sensitivity. Our imaging method works
under ambient conditions and can measure ubiquitous 'dark' spins, which
constitute nearly all spin targets of interest and cannot otherwise be
individually detected. In this technique, the magnetic quantum-projection noise
of dark spins is measured using a single nitrogen-vacancy (NV) magnetometer
located near the surface of a diamond chip. The spatial distribution of spins
surrounding the NV magnetometer is imaged with a scanning magnetic-field
gradient. To evaluate the performance of the NV-MRI technique, we image the
three-dimensional landscape of dark electronic spins at and just below the
diamond surface and achieve an unprecedented combination of resolution (0.8 nm
laterally and 1.5 nm vertically) and single-spin sensitivity. Our measurements
uncover previously unidentified electronic spins on the diamond surface, which
can potentially be used as resources for improved magnetic imaging of samples
proximal to the NV-diamond sensor. This three-dimensional NV-MRI technique is
immediately applicable to diverse systems including imaging spin chains,
readout of individual spin-based quantum bits, and determining the precise
location of spin labels in biological systems.",1401.2674v2
2016-06-17,Discrimination between spin-dependent charge transport and spin dependent recombination in π-conjugated polymers by correlated current and electroluminescence-detected magnetic resonance,"Spin-dependent processes play a crucial role in organic electronic devices.
Spin coherence can give rise to spin mixing due to a number of processes such
as hyperfine coupling, and leads to a range of magnetic field effects. However,
it is not straightforward to differentiate between pure single-carrier
spin-dependent transport processes which control the current and therefore the
electroluminescence, and spin-dependent electron-hole recombination which
determines the electroluminescence yield and in turn modulates the current. We
therefore investigate the correlation between the dynamics of spin-dependent
electric current and spin-dependent electroluminescence in two derivatives of
the conjugated polymer poly(phenylene-vinylene) using simultaneously measured
pulsed electrically detected (pEDMR) and optically detected (pODMR) magnetic
resonance spectroscopy. This experimental approach requires careful analysis of
the transient response functions under optical and electrical detection. At
room temperature and under bipolar charge-carrier injection conditions, a
correlation of the pEDMR and the pODMR signals is observed, consistent with the
hypothesis that the recombination currents involve spin-dependent electronic
transitions. This observation is inconsistent with the hypothesis that these
signals are caused by spin-dependent charge carrier transport. These results
therefore provide no evidence that supports earlier claims that spindependent
transport plays a role for room temperature magnetoresistance effects. At low
temperatures, however, the correlation between pEDMR and pODMR is weakened,
demonstrating that more than one spin-dependent process influences the
optoelectronic materials properties.",1606.05680v1
2013-12-19,Dynamics of a localized spin excitation close to the spin-helix regime,"The time evolution of a local spin excitation in a (001)-confined
two-dimensional electron gas subjected to Rashba and Dresselhaus spin-orbit
interactions of similar strength is investigated theoretically and compared
with experimental data. Specifically, the consequences of the finite spatial
extension of the initial spin polarization is studied for non-balanced Rashba
and Dresselhaus terms and for finite cubic Dresselhaus spin-orbit interaction.
We show that the initial out-of-plane spin polarization evolves into a helical
spin pattern with a wave number that gradually approaches the value $q_0$ of
the persistent spin helix mode. In addition to an exponential decay of the spin
polarization that is proportional to both the spin-orbit imbalance and the
cubic Dresselhaus term, the finite width $w$ of the spin excitation reduces the
spin polarization by a factor that approaches $\exp(-q_0^2 w^2/2)$ at longer
times.",1312.5529v1
2015-05-13,Excitations in a spin-polarized tow-dimensional electron gas,"A remarkably long-lived spin plasmon may exist in two-dimensional electron
liquids with imbalanced spin up and spin down population. Predictions for this
interesting mode by Agarwal et al. [Phys. Rev. B 90, 155409 (2014)] are based
on the random phase approximation. We here show how to account for spin
dependent correlations from known ground state pair correlation functions and
study the consequences on the various spin dependent longitudinal response
functions. The spin plasmon dispersion relation and its critical wave vector
for Landau damping by minority spins turn out to be significantly lowered. We
further demonstrate that spin dependent effective interactions imply a rich
structure in the excitation spectrum of the partially spin-polarized system.
Most notably, we find a ""magnetic antiresonance"", where the imaginary part of
both, the spin-spin as well as the density-spin response function vanish. The
resulting minimum in the double-differential cross section is awaiting
experimental confirmation.",1505.03370v3
2019-09-30,Ultrathin SnTe films as a route towards all-in-one spintronics devices,"Spin transistors based on a semiconducting channel attached to ferromagnetic
electrodes suffer from fast spin decay and extremely low spin
injection/detection efficiencies. Here, we propose an alternative all-in-one
spin device whose operation principle relies on electric manipulation of the
spin lifetime in two-dimensional (2D) SnTe, in which the sizable spin Hall
effect eliminates the need for using ferromagnets. In particular, we explore
the persistent spin texture (PST) intrinsically present in the ferroelectric
phase which protects the spin from decoherence and supports extraordinarily
long spin lifetime. Our first-principles calculations followed by symmetry
arguments revealed that such a spin wave mode can be externally detuned by
perpendicular electric field, leading to spin randomization and decrease in
spin lifetime. We further extend our analysis to ultrathin SnTe films and
confirm the emergence of PST as well as a moderate enhancement of intrinsic
spin Hall conductivity. The recent room-temperature observation of the
ferroelectric phase in 2D-SnTe suggests that novel all-electric spintronics
devices are within reach.",1909.13865v2
2013-08-24,Spin Dynamics in Graphene and Graphene like Nanocarbon Doped with Nitrogen the ESR Analysis,"Nano engineered spin degree of freedom in carbon system may offer desired
exchange coupling with optimum spin orbit interaction which is essential, to
construct solid state qubits, for fault tolerant quantum computation. The
purpose of this communication is to analyze spin dynamics of, basically, four
types of systems, (i) Graphene (system with inversion symmetry), (ii) Graphene
like nanocarbons (GNCs, broken inversion symmetry and heterostructure, sp2 and
sp3, environment), and (iii) their nitrogen doped derivatives. The spin
transport data was obtained using the electron spin resonance spectroscopy
(ESR) technique, carried out over 123 to 473K temperature range. Analysis of
shape, linewidths of dispersion derivatives,, and g factor anisotropy has been
carried out. Spin parameters such as, spin spin relaxation time, spin lattice
relaxation time, spin flip parameter,spin relaxation rate,spin, momentum
relaxation rate,pseudo chemical potential, density of states, effective
magnetic moment, spin concentration, defect concentration, and Pauli
susceptibility, has been estimated, and examined for their temperature as well
as interdependence. Details of the analysis are presented. The quantitative
study underlined the following facts: (i) by and large, spin dynamics in
Graphene and GNCs is significantly different, (ii) transport of spin behaves in
opposite fashion, after doping nitrogen, in both the systems, (iii) reduction
in the magnetization has been observed for both GNCs and Graphene, after doping
nitrogen, (iv) hyperfine interactions have been observed in all classes of
systems except in GNCs, (v) nitrogen doped GNCs seems to be appropriate for
qubit designing.",1308.5291v1
2021-10-21,The spin-spin problem in Celestial Mechanics,"We study the dynamics of two homogeneous rigid ellipsoids subject to their
mutual gravitational influence. We assume that the spin axis of each ellipsoid
coincides with its shortest physical axis and is perpendicular to the orbital
plane. Due to such assumptions, the problem is planar and depends on particular
parameters of the ellipsoids, most notably, the equatorial oblateness and the
flattening with respect to the shortest physical axes. We consider two models
for such configuration: while in the full model, there is a coupling between
the orbital and rotational motions, in the Keplerian model, the centers of mass
of the bodies are constrained to move on coplanar Keplerian ellipses. The
Keplerian case, in the approximation that includes the coupling between the
spins of the two ellipsoids, is what we call spin-spin problem, that is a
generalization of the classical spin-orbit problem. In this paper we continue
the investigations of [Mis21] on the spin-spin problem by comparing it with the
spin-orbit problem and also with the full model.
  Beside detailing the models associated to the spin-orbit and spin-spin
problems, we introduce the notions of standard and balanced resonances, which
lead us to investigate the existence of periodic and quasi-periodic solutions.
We also give a qualitative description of the phase space and provide results
on the linear stability of solutions for the spin-orbit and spin-spin problems.
We conclude by providing a comparison between the full and the Keplerian models
with particular reference to the interaction between the rotational and orbital
motions.",2110.11152v1
2020-07-24,"Determination of the spin Hall angle, spin mixing conductance and spin diffusion length in Ir/CoFeB for spin-orbitronic devices","Iridium is a very promising material for spintronic applications due to its
interesting magnetic properties such as large RKKY exchange coupling as well as
its large spin-orbit coupling value. Ir is for instance used as a spacer layer
for perpendicular synthetic antiferromagnetic or ferrimagnet systems. However,
only a few studies of the spintronic parameters of this material have been
reported. In this paper, we present inverse spin Hall effect - spin pumping
ferromagnetic resonance measurements on CoFeB/Ir based bilayers to estimate the
values of the effective spin Hall angle, the spin diffusion length within
iridium, and the spin mixing conductance in the CoFeB/Ir bilayer. In order to
have reliable results, we performed the same experiments on CoFeB/Pt bilayers,
which behavior is well known due to numerous reported studies. Our experimental
results show that the spin diffusion length within iridium is 1.3 nm for
resistivity of 250 n$\Omega$.m, the spin mixing conductance $g_{eff}^{\uparrow
\downarrow}$ of the CoFeB/Ir interface is 30 nm$^{-2}$, and the spin Hall angle
of iridium has the same sign than the one of platinum and is evaluated at 26%
of the one of platinum. The value of the spin Hall angle found is 7.7% for Pt
and 2% for Ir. These relevant parameters shall be useful to consider Ir in new
concepts and devices combining spin-orbit torque and spin-transfer torque.",2007.12413v1
2000-08-23,"Two-step contribution to the spin-longitudinal and spin-transverse cross sections of the quasielastic (p,n) reactions","The two-step contribution to the spin-longitudinal and the spin-transverse
cross sections of ^{12}C,^{40}Ca(p,n) reactions at 494 MeV and 346 MeV is
calculated. We use a plane-wave approximation and evaluate the relative
contributions from the one-step and the two-step processes. We found that the
ratios of the two-step to the one-step processes are larger in the
spin-transverse cross sections than in the spin-longitudinal ones. Combining
these results with the distorted-wave impulse approximation (DWIA) results we
obtained considerable two-step contributions to the spin-longitudinal and the
spin-transverse cross sections. The two-step processes are important in
accounting for the underestimation of the DWIA results for the
spin-longitudinal and the spin-transverse cross sections.",0008045v2
2006-05-23,All-electrical control of single ion spins in a semiconductor,"We propose a method for all-electrical initialization, control and readout of
the spin of single ions substituted into a semiconductor. Mn ions in GaAs form
a natural example. In the ion's ground state the Mn core spin magnetic moment
locks antiparallel to the spin and orbital magnetic moment of a bound valence
hole from the GaAs host. Direct electrical manipulation of the ion spin is
possible because electric fields manipulate the orbital wave function of the
hole, and through the spin-orbit coupling the spin is reoriented as well.
Coupling two or more ion spins can be achieved using electrical gates to
control the size of the valence hole wave function near the semiconductor
surface. This proposal for coherent manipulation of individual ionic spins and
controlled coupling of ionic spins via electrical gates alone may find
applications in extremely high density information storage and in scalable
coherent or quantum information processing.",0605203v2
2008-07-14,Electric-field induced spin excitations in two-dimensional spin-orbit coupled systems,"Rigorous coupled spin-charge drift-diffusion equations are derived from
quantum-kinetic equations for the spin-density matrix that incorporate effects
due to k-linear spin-orbit interaction, an in-plane electric field, and the
elastic scattering on nonmagnetic impurities. The explicit analytical solution
for the induced magnetization exhibits a pole structure, from which the
dispersion relations of spin excitations are identified. Applications of the
general approach refer to the excitation of long-lived field-induced spin waves
by optically generated spin and charge patterns. This approach transfers
methods known in the physics of space-charge waves to the treatment of spin
eigenmodes. In addition, the amplification of an oscillating electric field by
spin injection is demonstrated.",0807.2142v1
2012-05-10,"3D quaternionic condensations, Hopf invariants, and skyrmion lattices with synthetic spin-orbit coupling","We study the topological configurations of the two-component condensates of
bosons with the $3$D $\vec{\sigma}\cdot \vec{p}$ Weyl-type spin-orbit coupling
subject to a harmonic trapping potential. The topology of the condensate
wavefunctions manifests in the quaternionic representation. In comparison to
the $U(1)$ complex phase, the quaternionic phase manifold is $S^3$ and the spin
orientations form the $S^2$ Bloch sphere through the 1st Hopf mapping. The
spatial distributions of the quaternionic phases exhibit the 3D skyrmion
configurations, and the spin distributions possess non-trivial Hopf invariants.
Spin textures evolve from the concentric distributions at the weak spin-orbit
coupling regime to the rotation symmetry breaking patterns at the intermediate
spin-orbit coupling regime. In the strong spin-orbit coupling regime, the
single-particle spectra exhibit the Landau-level type quantization. In this
regime, the three-dimensional skyrmion lattice structures are formed when
interactions are below the energy scale of Landau level mixings. Sufficiently
strong interactions can change condensates into spin-polarized plane-wave
states, or, superpositions of two plane-waves exhibiting helical spin spirals.",1205.2162v3
2014-10-28,A solution of the Boltzmann transport equations for spin and charge transport in a solid. Spin Proximity effect,"A solution of the modified Boltzmann transport equations is found, which
describes features of the spin and charge transport in a solid. Two
modifications of the Boltzmann transport equation were introduced. The first
modification describes the fact that a delocalized electrons can either be of
the running-wave type or the standing-wave type and electrons of different
types contribute differently to the transport. The second modification includes
the fact that the direction of the electron spin may not be conserved after
frequent electron scatterings. The origins and features of the spin proximity,
spin injection and spin detection effects are described. An enhancement of spin
detection and spin injection efficiencies in the vicinity of an interface are
predicted. The physical mechanism of an enlargement of spin accumulation due to
the conventional Hall effect is described.",1410.7511v1
2015-03-26,Spin nematic fluctuations near a spin-density-wave phase,"We study an interacting electronic system exhibiting a spin nematic
instability. Using a phenomenological form for the spin fluctuation spectrum
near the spin-density-wave (SDW) phase, we compute the spin nematic
susceptibility in energy and momentum space as a function of temperature and
the magnetic correlation length xi. The spin nematic instability occurs when xi
reaches a critical value xi_{cr}, i.e., its transition temperature T_{SN} is
always higher than the SDW critical temperature T_{SDW}. In particular, xi_{cr}
decreases monotonically with increasing T_{SN}. Concomitantly, low-energy
nematic fluctuations are present in a wider temperature region as T_{SN}
becomes higher. Approaching the spin nematic instability, the nematic spectral
function at zero momentum exhibits a central peak as a function of energy for a
finite temperature and a soft mode at zero temperature. These properties
originate from the general feature that the imaginary part of the
spin-fluctuation bubble has a term linear in energy and its coefficient is
proportional to the square of temperature. Furthermore we find that the nematic
spectral function exhibits a diffusive peak around zero momentum and zero
energy without clear dispersive features. A possible phase diagram for the spin
nematic and SDW transitions is also discussed.",1503.07646v1
2015-04-14,Spin dynamics in relativistic light-matter interaction,"Various spin effects are expected to become observable in light-matter
interaction at relativistic intensities. Relativistic quantum mechanics
equipped with a suitable relativistic spin operator forms the theoretical
foundation for describing these effects. Various proposals for relativistic
spin operators have been offered by different authors, which are presented in a
unified way. As a result of the operators' mathematical properties only the
Foldy-Wouthuysen operator and the Pryce operator qualify as possible proper
relativistic spin operators. The ground states of highly charged hydrogen-like
ions can be utilized to identify a legitimate relativistic spin operator
experimentally. Subsequently, the Foldy-Wothuysen spin operator is employed to
study electron-spin precession in high-intensity standing light waves with
elliptical polarization. For a correct theoretical description of the predicted
electron-spin precession relativistic effects due to the spin angular momentum
of the electromagnetic wave has to be taken into account even in the limit of
low intensities.",1504.03489v1
2017-09-28,Spin-orbit interaction of light induced by transverse spin angular momentum engineering,"We report the first demonstration of a direct interaction between the
extraordinary transverse spin angular momentum in evanescent waves and the
intrinsic orbital angular momentum in optical vortex beams. By tapping the
evanescent wave of whispering gallery modes in a micro-ring-based optical
vortex emitter and engineering the transverse spin state carried therein, a
transverse-spin-to-orbital conversion of angular momentum is predicted in the
emitted vortex beams. Numerical and experimental investigations are presented
for the proof-of-principle demonstration of this unconventional interplay
between the spin and orbital angular momenta, which could provide new
possibilities and restrictions on the optical angular momentum manipulation
techniques on the sub-wavelength scale. This phenomenon further gives rise to
an enhanced spin-direction coupling effect in which waveguide or surface modes
are unidirectional excited by incident optical vortex, with the directionality
jointly controlled by spin-orbit states. Our results enrich the spin-orbit
interaction phenomena by identifying a previously unknown pathway between the
polarization and spatial degrees of freedom of light, and can enable a variety
of functionalities employing spin and orbital angular momenta of light in
applications such as communications and quantum information processing.",1709.09811v1
2008-06-05,Magnetization Relaxation and Collective Spin Excitations in Correlated Double--Exchange Ferromagnets,"We study spin relaxation and dynamics of collective spin excitations in
correlated double--exchange ferromagnets. For this, we introduce an expansion
of the Green's functions equations of motion that treats non--perturbativerly
all correlations between a given number of spin and charge excitations and
becomes exact within a sub--space of states. Our method treats relaxation
beyond Fermi's Golden Rule while recovering previous variational results for
the spin--wave dispersion. We find that the momentum dependence of the
spin--wave dephasing rate changes qualitatively due to the on--site Coulomb
interaction, in a way that resembles experiment, and depends on its interplay
with the magnetic exchange interaction and itinerant spin lifetime. We show
that the collective spin relaxation and its dependence on the carrier
concentration depends sensitively on three--body correlations between a spin
excitation and a Fermi sea electron and hole. The above spin dynamics can be
controlled via the itinerant carrier population.",0806.0938v2
2017-04-06,Spin-valley half-metal as a prospective material for spin-valley-tronics,"Half-metallicity (full spin polarization of the Fermi surface) usually occurs
in strongly correlated electron systems. We demonstrate that doping a
spin-density wave insulator in the weak-coupling regime may also stabilize
half-metallic states. The undoped spin-density wave is formed by four nested
bands [i.e., each band is characterized by charge (electron/hole) and spin
(up/down) labels]. Of these four bands only two accumulate the doped carriers,
forming a half-metallic two-valley Fermi surface. Depending on parameters, the
spin polarizations of the electron-like and hole-like valleys may be (i)
parallel or (ii) antiparallel. The Fermi surface of (i) is fully spin-polarized
(similar to usual half-metals). Case (ii), referred to as ""a spin-valley
half-metal"", corresponds to complete polarization with respect to the
spin-valley operator. The properties of these states are discussed.",1704.01727v1
2021-01-09,Many-particle Quantum Hydrodynamics of Spin-1 Bose-Einstein Condensates,"We develop a novel model of the magnetized spin-1 Bose-Einstein condensate
(BEC) of neutral atoms, using the method of many-particle quantum hydrodynamic
(QHD) and propose an original derivation of the system of continual equations.
We consider bosons with a spin-spin interaction and a short range interaction
in the first order in the interaction radius, on the of basis of the
self-consistent field approximation of the QHD equations. We demonstrate that
the dynamics of the fluid velocity and magnetization is determined by a
nontrivial modification of the Euler and Landau-Lifshitz equation, and show
that a nontrivial modification of the spin density evolution equation contains
the spin torque effect that arises from the self-interactions between spins of
the bosons. The properties of the dispersion spectrum of collective excitations
are described. We obtain the new contribution of the self-interaction of spins
in the spin wave spectrum together with the influence of an external magnetic
field and spin-spin interactions between polarized particles. The anisotropic
spin wave instability is predicted.",2101.03422v1
2021-12-02,Spin dynamics of the spin chain antiferromagnet RbFeS$_2$,"We report transport and inelastic neutron scattering studies on electronic
properties and spin dynamics of the quasi-one-dimensional spin chain
antiferromagnet RbFeS$_2$. An antiferromagnetic phase transition at
$T_N\approx195$ K and dispersive spin waves with a spin gap of 5 meV are
observed. By modeling the spin excitation spectra using linear spin wave
theory, intra and inter-chain exchange interactions are found to be
$SJ_1=100(5)$ meV and $SJ_3=0.9(3)$ meV, respectively, together with a small
single-ion anisotropy of $SD_{zz}=0.04(1)$ meV. Comparison with previous
results for other materials in the same class of Fe$^{3+}$ spin chain systems
reveals that although the magnetic order sizes show significant variation from
1.8 to 3.0$\mu_B$ within the family of materials, the exchange interactions
$SJ$ are nevertheless quite similar, analogous to the iron pnictide
superconductors where both localized and delocalized electrons contribute to
the spin dynamics.",2112.00951v3
2022-01-04,Mechanism of antisymmetric spin polarization in centrosymmetric multiple-$Q$ magnets based on bilinear and biquadratic spin cross products,"We investigate how to engineer an antisymmetric spin-split band structure
under spin density waves with finite ordering wave vectors in centrosymmetric
systems without the relativistic spin-orbit coupling. On the basis of a
perturbative analysis for the spin-charge coupled model in centrosymmetric
itinerant magnets, we show that nonzero chiral-type bilinear and biquadratic
spin cross products in momentum space under the magnetic orderings are related
to an antisymmetric spin polarization in the electronic band structure. We
apply the derived formula to the single-$Q$ cycloidal spiral and double-$Q$
noncoplanar states including the meron-antimeron and skyrmion crystals. Our
results present a clue to realize a giant antisymmetric spin splitting driven
by magnetic phase transitions in the centrosymmetric lattice structures without
the spin-orbit coupling.",2201.01354v1
2024-02-11,Inferring small neutron star spins with neutron star-black hole mergers,"The precise measurement of neutron star (NS) spins can provide important
insight into the formation and evolution of compact binaries containing NS.
While traditional methods of NS spin measurement rely on pulsar observations,
gravitational wave detections offer a complementary avenue. However,
determining component spins with gravitational waves is hindered by the small
dimensionless spins of the NS and the degeneracy in the mass and spin
parameters. This degeneracy can be addressed by the inclusion of higher-order
modes in the waveform, which are important for systems with unequal masses.
This study shows the suitability of neutron star-black hole mergers, which are
naturally mass-asymmetric, for precise NS spin measurements. We explore the
effects of the black hole masses and spins, higher-mode content, inclination
angle, and detector sensitivity on the measurement of NS spin. We find that
networks with next-generation observatories like the Cosmic Explorer and the
Einstein Telescope can distinguish NS dimensionless spin of 0.04 (0.1) from
zero at $1-\sigma$ confidence for events within $\sim 350$ $(\sim 1000)$ Mpc.
Networks with A+ and A$^{\sharp}$ detectors achieve similar distinction within
$\sim 30$ $(\sim 70)$ Mpc and $\sim 50$ $(\sim 110)$ Mpc, respectively.",2402.07075v1
1995-01-30,On the spin density wave transition in a two dimensional spin liquid,"Strongly correlated two dimensional electrons are believed to form a spin
liquid in some regimes of density and temperature. As the density is varied,
one expects a transition from this spin liquid state to a spin density wave
antiferromagnetic state. In this paper we show that it is self-consistent to
assume that this transition is second order and, on this assumption, determine
the critical behavior of the $2p_F$ susceptibility, the NMR rates $T_1$ and
$T_2$ and the uniform susceptibility. We compare our results to data on high
$T_c$ materials.",9501133v1
1997-07-07,Spin Liquid Phases in 2D Frustrated XY Model,"In this paper we consider the $J_1-J_2-J_3$ classical and quantum 2D XY
model. Spin wave calculations show that a spin liquid phase still exists in the
quantum case as for Heisenberg models. We formulate a semiclassical approach of
these models based on spin wave action and use a variational method to study
the role played by vortices. Liquid and crystal phases of vortex could emerge
in this description. These phases seem to be directly correlated with the spin
liquid one and to its crystalline interpretation.",9707074v1
1998-08-18,Spin-density-functional theory of circular and elliptical quantum dots,"Using spin-density-functional theory, we study the electronic states of a
two-dimensional parabolic quantum dot with up to N=58 electrons. We observe a
shell structure for the filling of the dot with electrons. Hund's rule
determines the spin configuration of the ground state, but only up to 22
electrons. At specific N, the ground state is degenerate, and a small
elliptical deformation of the external potential induces a rotational
charge-density-wave (CDW) state. Previously identified spin-density-wave (SDW)
states are shown to be artifacts of broken spin symmetry in density-functional
theory.",9808193v1
1999-08-16,Current-driven Magnetization Reversal and Spin Wave Excitations in Co/Cu/Co Pillars,"Using thin film pillars ~100 nm in diameter, containing two ferromagnetic Co
layers of different thicknesses separated by a paramagnetic Cu spacer, we
examine effects of torques due to spin-polarized currents flowing perpendicular
to the layers. In accordance with spin-transfer theory, spin-polarized
electrons flowing from the thin to the thick Co layer can switch the magnetic
moments of the layers antiparallel, while a reversed electron flow causes
switching to a parallel state. When large magnetic fields are applied, the
current no longer fully reverses the magnetic moment, but instead stimulates
spin-wave excitations.",9908231v1
2000-12-10,Theory of spin wave excitations of metallic A-type antiferromagnetic manganites,"The spin dynamic of the metallic A-type antiferromagnetic manganites is
studied. An effective nearest-neighbour Heisenberg spin wave dispersion is
derived from the double exchange model taking into account the superexchange
interaction between the core spins. The result of inelastic neutron scattering
experiment on ${Nd}_{0.45}{Sr}_{0.55}{Mn} {O}_{3}$ is qualitatively reproduced.
Comparing theory with experimental data two main parameters of the model:
nearest-neighbour electron transfer amplitude and superexchange coupling
between the core spins are estimated.",0012166v2
2002-10-10,Spin wave theory for antiferromagnetic XXZ spin model on a triangle lattice in the presence of an external magnetic field,"Spin wave theory is applied to a quantum antiferromagnetic XXZ model on a
triangle lattice in the presence of an in-plane magnetic field. The effect of
the field is found to enhance the quantum fluctuation and to reduce the
sublattice magnetization at the intermediate field strength in the anisotropic
case. The possible implication to the field driven quantum phase transition
from a spin solid to a spin liquid is discussed.",0210222v1
2003-06-10,Correlation functions for 1d interacting fermions with spin-orbit coupling,"We compute correlation functions for one-dimensional electron systems which
spin and charge degrees of freedom are coupled through spin-orbit coupling.
Charge density waves, spin density waves, singlet- triplet- superconducting
fluctuations are studied. We show that the spin-orbit interaction modify the
exponents and the phase diagram of the system, changing the dominant
fluctuations and making new susceptibilities diverge for low temperature.",0306251v1
2003-08-06,Exciton Spin Relaxation Time in Quantum Dots Measured by Continuous-Wave Photoluminescence Spectroscopy,"We demonstrate a new method of measuring the exciton spin relaxation time in
semiconductor nanostructures by continuous-wave photoluminescence. We find that
for self-assembled CdTe quantum dots the degree of circular polarization of
emission is larger when exciting polarized excitons into the lower energy spin
state than in the case when the excitons are excited into the higher energy
spin state. A simple rate equation model gives the exciton spin relaxation time
in CdTe quantum dots equal to 4.8+/-0.3 ns, significantly longer than the
quantum dot exciton recombination time 300 ps.",0308116v1
2004-11-10,Maxwell Equation for the Coupled Spin-Charge Wave Propagation,"We show that the dissipationless spin current in the ground state of the
Rashba model gives rise to a reactive coupling between the spin and charge
propagation, which is formally identical to the coupling between the electric
and the magnetic fields in the 2+1 dimensional Maxwell equation. This analogy
leads to a remarkable prediction that a density packet can spontaneously split
into two counter propagation packets, each carrying the opposite spins. In a
certain parameter regime, the coupled spin and charge wave propagates like a
transverse ""photon"". We propose both optical and purely electronic experiments
to detect this effect.",0411276v1
2005-05-18,Spin Dynamics in the Two-Dimensional Spin 1/2 Heisenberg Antiferromagnet,"We present low-temperature dynamic properties of the quantum two-dimensional
antiferromagnetic Heisenberg model with spin S=1/2. The calculation of the
dynamic correlation function is performed by combining a projection operator
formalism and the modified spin-wave theory (MSW), which gives a gap in the
dispersion relation for finite temperatures. The so calculated dynamic
correlation function shows a double peak structure.We also obtain the spin-wave
damping and compare our results to experimental data and to theoretical results
obtained by other authors using different approaches.",0505458v1
2005-07-01,Spin accumulation in ballistic Rashba bar,"We propose an analytic model to study intrinsic spin polarization effect in a
ballistic Rashba bar with two semi-infinite leads. The wave functions expanded
with plane waves in Rashba bar are required to satisfy boundary conditions at
both longitudinal and transverse interfaces. We find out-of-plane spin Hall
accumulation effect can be induced in the Rashba bar even with large dimensions
by injecting unpolarized current from the lead. The longitudinal in-plane spin
Hall effect, however, becomes obscure in large-size sample. An interesting
direction-flipping of the out-of-plane spin accumulation is predicted by
altering the Rashba coupling strength.",0507025v1
2005-08-29,Spin-Phonon Coupling in High-T_c Copper Oxides,"Band calculations on HgBa$_2$CuO$_4$ and La$_{(2-x)}$Sr$_x$CuO$_4$ with
phonon and spin-waves within the CuO planes show that partial gaps are created
at various energies depending on wavelengths. Spin and phonon gaps appear at
different energies when the modulations are along [1,1,0], while they are at
the same energy for modulations along [1,0,0].
  It is shown that the ability to form gaps and antiferromagnetic waves is
correlated with the strength of the interaction parameter $\lambda_{sf}$ for
spin fluctuations. Many unusual properties of the high-T$_C$ oxides can be
understood from spin-phonon coupling.",0508672v1
2006-02-23,Two-dimensional electron scattering in regions of nonuniform spin-orbit coupling,"We present a theoretical study of elastic spin-dependent electron scattering
caused by a nonuniform Rashba spin-orbit coupling strength. Using the
spin-generalized method of partial waves the scattering amplitude is exactly
derived for the case of a circular shape of scattering region. We found that
the polarization of the scattered waves are strongly anisotropic functions of
the scattering angle. This feature can be utilized to design a good
all-electric spin-polarizer. General properties of the scattering process are
also investigated in the high and low energy limits.",0602560v1
2006-06-02,Parametric instability of homogeneous precession of spin in the superfluid 3He-B,"Stability of homogeneous precession of spin due to parametric excitation of
spin waves is considered as the explanation of the ""catastrophic relaxation"",
that is observed in the superfluid 3He-B. It is shown, that at sufficiently low
temperatures homogeneous precession of spin becomes unstable (Suhl
instability). At zero temperature increments of growth for all spin wave modes
are found. Estimation of the temperature of transition to the unstable state is
made.",0606054v1
2006-10-13,Efficient switching of Rashba spin splitting in wide modulation-doped quantum wells,"We demonstrate that the size of the electric-field-induced Rashba spin
splitting in an 80 nm wide modulation-doped InGaSb quantum well can depend
strongly on the spatial variation of the electric field. In a slightly
asymmetric quantum well it can be an order of magnitude stronger than for the
average uniform electric field. For even smaller asymmetry spin subbands can
have wave functions and/or expectation values of the spin direction that are
completely changed as the in-plane wave vector varies. The Dresselhaus effect
can give an anticrossing at which the spin rapidly flips.",0610371v1
2007-02-07,Damping of antiferromagnetic spin waves by valence fluctuations in the double layer perovskite YBaFe2O5,"Inelastic neutron scattering experiments show that spin dynamics in the
charge ordered insulating ground state of the double-layer perovskite YBaFe2O5
is well described in terms of eg superexchange interactions. Above the Verwey
transition at TV = 308 K, t2g double exchange-type conduction within
antiferromagnetic FeO2--BaO--FeO2 double layers proceeds by an electron hopping
process that requires a spin flip of the five-fold coordinated Fe ions, costing
an energy 5<J>S^2 of approximately 0.1 eV. The hopping process disrupts
near-neighbor spin correlations, leading to massive damping of zone-boundary
spin waves.",0702181v1
2002-07-02,Gravitational Waves from Spinning Compact Binaries,"Binary systems of rapidly spinning compact objects, such as black holes or
neutron stars, are prime targets for gravitational wave astronomers. The
dynamics of these systems can be very complicated due to spin-orbit and
spin-spin couplings. Contradictory results have been presented as to the nature
of the dynamics. Here we confirm that the dynamics - as described by the second
post-Newtonian approximation to general relativity - is chaotic, despite claims
to the contrary. When dissipation due to higher order radiation reaction terms
are included, the chaos is dampened. However, the inspiral-to-plunge transition
that occurs toward the end of the orbital evolution does retain an imprint of
the chaotic behaviour.",0207016v1
2006-04-05,Self interaction of spins in binary systems,"Beyond point mass effects various contributions add to the radiative
evolution of compact binaries. We present all the terms up to the second
post-Newtonian order contributing to the rate of increase of gravitational wave
frequency and the number of gravitational wave cycles left until the final
coalescence for binary systems with spin, mass quadrupole and magnetic dipole
moments, moving on circular orbit. We evaluate these contributions for some
famous or typical compact binaries and show that the terms representing the
self interaction of individual spins, given for the first time here, are
commensurable with the proper spin-spin contributions for the recently
discovered double pulsar J0737-3039.",0604022v1
2004-09-02,Spinning particle in an external linearized gravitational wave field,"We study the interaction of a scalar and a spinning particle with a coherent
linearized gravitational wave field treated as a classical spin two external
field. The spin degrees of freedom of the spinning particle are described by
skew-commuting variables. We derive the explicit expressions for the
eigenfunctions and the Green's functions of the theory. The discussion is exact
within the approximation of neglecting radiative corrections and we prove that
the result is completely determined by the semiclassical contribution.",0409027v1
2005-07-28,Quantum entanglement dynamics and decoherence wave in spin chains at finite temperatures,"We analyze the quantum entanglement at the equilibrium in a class of exactly
solvable one-dimensional spin models at finite temperatures and identify a
region where the quantum fluctuations determine the behavior of the system. We
probe the response of the system in this region by studying the spin dynamics
after projective measurement of one local spin which leads to the appearance of
the ``decoherence wave''. We investigate time-dependent spin correlation
functions, the entanglement dynamics, and the fidelity of the quantum
information transfer after the measurement.",0507266v1
2008-03-25,Long range order for lattice dipoles,"We consider a system of classical Heisenberg spins on a cubic lattice in
dimensions three or more, interacting via the dipole-dipole interaction. We
prove that at low enough temperature the system displays orientational long
range order, as expected by spin wave theory. The proof is based on reflection
positivity methods. In particular, we demonstrate a previously unproven
conjecture on the dispersion relation of the spin waves, first proposed by
Froehlich and Spencer, which allows one to apply infrared bounds for estimating
the long distance behavior of the spin-spin correlation functions.",0803.3576v1
2008-09-23,The Spin Distribution of Millisecond X-ray Pulsars,"The spin frequency distribution of accreting millisecond X-ray pulsars cuts
off sharply above 730 Hz, well below the breakup spin rate for most neutron
star equations of state. I review several different ideas for explaining this
cutoff. There is currently considerable interest in the idea that gravitational
radiation from rapidly rotating pulsars might act to limit spin up by
accretion, possibly allowing eventual direct detection with gravitational wave
interferometers. I describe how long-term X-ray timing of fast accreting
millisecond pulsars like the 599 Hz source IGR J00291+5934 can test the
gravitational wave model for the spin frequency limit.",0809.4031v1
2008-09-24,Gated combo nanodevice for sequential operations on single electron spin,"An idea for a nanodevice in which an arbitrary sequence of three basic
quantum single qubit gates - negation, Hadamard and phase shift - can be
performed on a single electron spin. The spin state is manipulated using the
spin-orbit coupling and the electron trajectory is controlled by the electron
wave function self-focusing mechanism due to the electron interaction with the
charge induced on metal gates. We present results of simulations based on
iterative solution of the time dependent Schr\""odinger equation in which the
subsequent operations on the electron spin can be followed and controlled.
Description of the moving electron wave packet requires evaluation of the
electric field within the entire nanodevice in each time step.",0809.4195v1
2009-03-09,d-Wave Spin Density Wave phase in the Attractive Hubbard Model with Spin Polarization,"We investigate the possibility of unconventional spin density wave (SDW) in
the attractive Hubbard model with finite spin polarization. We show that
pairing and density fluctuations induce the transverse d-wave SDW near the
half-filling. This novel SDW is related to the d-wave superfluidity induced by
antiferromagnetic spin fluctuations, in the sense that they are connected with
each other through Shiba's attraction-repulsion transformation. Our results
predict the d-wave SDW in real systems, such as cold Fermi atom gases with
population imbalance and compounds involving valence skipper elements.",0903.1491v1
2009-03-12,Simulation of a spin-wave instability from atomistic spin dynamics,"We study the spin dynamics of a Heisenberg model at finite temperature in the
presence of an external field or a uniaxial anisotropy. For the case of the
uniaxial anisotropy our simulations show that the macro moment picture breaks
down. An effect which we refer to as a spin-wave instability (SWI) results in a
non-dissipative Bloch-Bloembergen type relaxation of the macro moment where the
size of the macro moment changes, and can even be made to disappear. This
relaxation mechanism is studied in detail by means of atomistic spin dynamics
simulations.",0903.2186v1
2010-09-13,Helical spin textures in dipolar Bose-Einstein condensates,"We numerically study elongated helical spin textures in ferromagnetic spin-1
Bose-Einstein condensates subject to dipolar interparticle forces. Stationary
states of the Gross-Pitaevskii equation are solved and analyzed for various
values of the helical wave vector and dipolar coupling strength. We find two
helical spin textures which differ by the nature of their topological defects.
The spin structure hosting a pair of Mermin-Ho vortices with opposite mass
flows and aligned spin currents is stabilized for a nonzero value of the
helical wave vector.",1009.2372v3
2012-04-27,Spin-dependent electron grating effect from helical magnetization in multiferroic tunnel junctions,"In multiferroic oxides with a transverse helical magnetic order, the
magnetization exchange coupling is sinusoidally space-dependent. We
theoretically investigate the spin-dependent electron grating effect in
normal-metal/helical-multiferroic/ferromagnettic heterojunctions. The spin wave
vector of the spiral can be added or subtracted from the electron spacial wave
vector inducing spin-conserved and spin-flipped diffracted transmission and
reflection. The predicted grating effect can be controlled by magnetization
exchange coupling strength, the helicity spatial period, and the magnetization
of the ferromagnetic layer.",1204.6095v1
2012-12-24,Landau versus Spin Superfluidity in Spinor Bose-Einstein Condensates,"We consider a spin-1/2 Bose-Einstein condensate prepared initially in a
single spin projection. The two channels of excitations existing in such a
system (namely density and spin waves) are discussed and we show how pure spin
waves can be excited in the presence of local magnetic defects. We analyze the
role played by spin excitations on the Landau superfluidity criterion and
demonstrate the absence of absolute superfluidity for the antiferromagnetic
condensate. In the ferromagnetic case, we identify two critical velocities for
the breakdown of superfluidity.",1212.5894v2
2013-07-05,Spin liquid phase due to competing classical orders in the semiclassical theory of the Heisenberg model with ring exchange on an anisotropic triangular lattice,"Linear spin wave theory shows that ring exchange induces a quantum disordered
region in the phase diagram of the title model. Spin wave spectra show that
this is a direct manifestation of competing classical orders. A spin liquid is
found in the `Goldilocks zone' of frustration, where the quantum fluctuations
are large enough to cause strong competition between different classical
orderings but not strong enough to stabilize spiral order. We note that the
spin liquid phases of $\kappa$-(BEDT-TTF)${_2}X$ and $Y$[Pd(dmit)$_2$]$_2$ are
found in this Goldilocks zone.",1307.1535v1
2014-11-03,Inelastic-impurity-scattering-induced spin texture and topological transitions in surface electron waves,"Inelastic scattering off magnetic impurities in a spin-chiral two-dimensional
electron gas, e.g., the Rashba system, is shown to generate topological changes
in the spin texture of the electron waves emanating from the scattering center.
While elastic scattering gives rise to a purely in-plane spin texture for an
in-plane magnetic scat- tering potential, out-of-plane components emerge upon
activation of inelastic scattering processes. This property leads to a
possibility to make controlled transitions between trivial and nontrivial
topologies of the spin texture.",1411.0377v3
2015-09-08,Anomalous Hall effect driven by dipolar spin waves in uniform ferromagnets,"A new type of anomalous Hall effect is shown to arise from the interaction of
conduction electrons with dipolar spin waves in ferromagnets. This effect
exists even in homogeneous ferromagnets without relativistic spin-orbit
coupling. The leading contribution to the Hall conductivity is proportional to
the chiral spin correlation of dynamical spin textures and is physically
understood in terms of the skew scattering by dipolar magnons.",1509.02284v1
2016-09-15,Route toward high-speed nano-magnonics,"We study experimentally the possibility to utilize pulses of pure spin
current, produced via the nonlocal spin injection mechanism, to generate short
packets of spin waves propagating in nanoscale magnetic waveguides. The
spatially and time-resolved micro-focus Brillouin light scattering spectroscopy
measurements demonstrate that the excitation by spin current results in
extremely fast transient response, enabling efficient generation of short
spin-wave packets with duration down to a few nanoseconds. The proposed method
opens a route for the implementation of high-speed magnonic systems for
transmission and processing of information on the nanoscale.",1609.04526v1
2012-09-27,Spin effects on gravitational waves from inspiraling compact binaries at second post-Newtonian order,"We calculate the gravitational waveform for spinning, precessing compact
binary inspirals through second post-Newtonian order in the amplitude. When
spins are collinear with the orbital angular momentum and the orbits are
quasi-circular, we further provide explicit expressions for the
gravitational-wave polarizations and the decomposition into spin-weighted
spherical-harmonic modes. Knowledge of the second post-Newtonian spin terms in
the waveform could be used to improve the physical content of analytical
templates for data analysis of compact binary inspirals and for more accurate
comparisons with numerical-relativity simulations.",1209.6349v2
2020-08-19,Loop spin effects in intense background fields,"Radiative and non-radiative electron spin flip probabilities are analysed in
both plane wave and focussed laser backgrounds. We provide a simple and
physically transparent description of spin dynamics in plane waves, and
demonstrate that there exists a kinematic regime in which the usual leading
order perturbative hierarchy of QED is reversed, and non-radiative loop effects
dominate over radiative tree-level spin-flips. We show that while this
loop-dominance becomes suppressed in focussed laser pulses due to a high
sensitivity to field geometry, there is nevertheless a regime in which, in
principle, loop effects on spin transitions can be discerned.",2008.08578v1
2019-03-30,Background noise pushes azimuthal instabilities away from spinning states,"Azimuthal instabilities occur in rotationally symmetric systems, either as
spinning (rotating) waves or standing waves. We make use of a novel ansatz to
derive a differential equation characterizing the state of these instabilities
in terms of their amplitude, orientation, nature (standing/spinning) and
temporal phase. For the first time we show how source terms determine
quantitatively the system preference for spinning and/or standing states. In
particular we find that, when present, background noise pushes the system away
from spinning states and towards standing states, consistently with
experiments.",1904.00213v1
2024-01-29,Dissipative effects on the propagation of spin modes,"In relativistic hydrodynamics with spin, following de Groot--van Leeuwen--van
Weert's energy-momentum and spin tensor definitions, we analyze the propagation
of spin degrees of freedom. We deduce an analytical formula for spin wave
velocity, finding that it approaches half the speed of light in the
ultra-relativistic limit. Only transverse degrees of freedom propagate, similar
to electromagnetic waves. Additionally, we explore dissipative effects and
determine the damping coefficients for Maxwell-J\""uttner statistics.",2401.16007v1
2018-10-16,Exact discrete resonances in the Fermi-Pasta-Ulam-Tsingou system,"In systems of N coupled anharmonic oscillators, exact resonant interactions
play an important role in the energy exchange between normal modes. In the
weakly nonlinear regime, those interactions may facilitate energy equipartition
in Fourier space. We consider analytically resonant wave-wave interactions for
the celebrated Fermi-Pasta-Ulam-Tsingou (FPUT) system. Using a
number-theoretical approach based on cyclotomic polynomials, we show that the
problem of finding exact resonances for a system of N particles is equivalent
to a Diophantine equation whose solutions depend sensitively on the set of
divisors of N. We provide an algorithm to construct all possible resonances,
based on two methods: pairing-off and cyclotomic, which we introduce to build
up explicit solutions to the 4-, 5- and 6-wave resonant conditions. Our results
shed some light in the understanding of the long-standing FPUT paradox,
regarding the sensitivity of the resonant manifolds with respect to the number
of particles N and the corresponding time scale of the interactions leading to
thermalisation. In this light we demonstrate that 6-wave resonances always
exist for any N, while 5-wave resonances exist if N is divisible by 3 and N >
6. It is known (for finite N) that 4-wave resonances do not mix energy across
the spectrum, so we investigate whether 5-wave resonances can produce energy
mixing across a significant region of the Fourier spectrum by analysing the
interconnected network of Fourier modes that can interact nonlinearly via
resonances. The answer depends on the set of odd divisors of N that are not
divisible by 3: the size of this set determines the number of dynamically
independent components, corresponding to independent constants of motion
(energies). We show that 6-wave resonances connect all these independent
components, providing in principle a restoring mechanism for full-scale
thermalisation.",1810.06902v1
2005-12-26,Spin waves in a band ferromagnet: spin-rotationally symmetric study with self-energy and vertex corrections,"First-order quantum corrections to the transverse spin-fluctuation propagator
are obtained within a systematic inverse-degeneracy 1/N expansion, which
provides a spin-rotationally symmetric scheme for including self-energy and
vertex corrections while preserving the Goldstone mode. An expression is
obtained for the spin-wave stiffness constant including all first-order quantum
corrections, and the dominant contribution is shown to yield a strong reduction
due to a correlation-induced enhancement in the exchange-energy gain upon spin
twisting. The quantum reduction factor U/W highlights the subtlety in the
characteristic competition in a band ferromagnet between interaction U and
bandwidth W. Quantum corrections also yield an intrinsic spin-wave damping
mechanism due to coupling between spin and charge fluctuations.",0512648v2
2010-05-12,Spin effects in the phasing of gravitational waves from binaries on eccentric orbits,"We compute here the spin-orbit and spin-spin couplings needed for an accurate
computation of the phasing of gravitational waves emitted by comparable-mass
binaries on eccentric orbits at the second post-Newtonian (PN) order. We use a
quasi-Keplerian parametrization of the orbit free of divergencies in the zero
eccentricity limit. We find that spin-spin couplings induce a residual
eccentricity for coalescing binaries at 2PN, of the order of
$10^{-4}$-$10^{-3}$ for supermassive black hole binaries in the LISA band.
Spin-orbit precession also induces a non-trivial pattern in the evolution of
the eccentricity, which could help to reduce the errors on the determination of
the eccentricity and spins in a gravitational wave measurement.",1005.2046v1
2012-05-10,"Multiboson spin-wave theory for Ba2CoGe2O7, a spin-3/2 easy-plane Neel antiferromagnet with strong single-ion anisotropy","We consider the square-lattice antiferromagnetic Heisenberg Hamiltonian
extended with a single-ion axial anisotropy term as a minimal model for the
multiferroic Ba2CoGe2O7. Developing a multiboson spin-wave theory, we
investigate the dispersion of the spin excitations in this spin-3/2 system. As
a consequence of a strong single-ion anisotropy, a stretching (longitudinal)
spin-mode appears in the spectrum. The inelastic neutron scattering spectra of
Zheludev et al. [Phys. Rev. B 68, 024428 (2003)] are successfully reproduced by
the low energy modes in the multiboson spin-wave theory, and we anticipate the
appearance of the spin stretching modes at 4meV that can be identified using
the calculated dynamical spin structure factors. We expect the appearance of
spin stretching modes for any S>1/2 compound where the single-ion anisotropy is
significant.",1205.2196v2
2015-01-07,Quadratic-in-spin effects in the orbital dynamics and gravitational-wave energy flux of compact binaries at the 3PN order,"We investigate the dynamics of spinning binaries of compact objects at the
next-to-leading order in the quadratic-in-spin effects, which corresponds to
the third post-Newtonian order (3PN). Using a Dixon-type multipolar formalism
for spinning point particles endowed with spin-induced quadrupoles and
computing iteratively in harmonic coordinates the relevant pieces of the PN
metric within the near zone, we derive the post-Newtonian equations of motion
as well as the equations of spin precession. We find full equivalence with
available results. We then focus on the far-zone field produced by those
systems and obtain the previously unknown 3PN spin contributions to the
gravitational-wave energy flux by means of the multipolar post-Minkowskian
(MPM) wave generation formalism. Our results are presented in the
center-of-mass frame for generic orbits, before being further specialized to
the case of spin-aligned, circular orbits. We derive the orbital phase of the
binary based on the energy balance equation and briefly discuss the relevance
of the new terms.",1501.01529v1
2018-06-13,Phase-locking between different partial-waves in atom-ion spin-exchange collisions,"We present a joint experimental and theoretical study of spin dynamics of a
single $^{88}$Sr$^+$ ion colliding with an ultracold cloud of Rb atoms in
various hyperfine states. While spin-exchange between the two species occurs
after 9.1(6) Langevin collisions on average, spin-relaxation of the Sr$^+$ ion
Zeeman qubit occurs after 48(7) Langevin collisions which is significantly
slower than in previously studied systems due to a small second-order
spin-orbit coupling. Furthermore, a reduction of the endothermic spin-exchange
rate was observed as the magnetic field was increased. Interestingly, we found
that, while the phases acquired when colliding on the spin singlet and triplet
potentials vary largely between different partial waves, the singlet-triplet
phase difference, which determines the spin-exchange cross-section, remains
locked to a single value over a wide range of partial-waves which leads to
quantum interference effects.",1806.05150v2
2019-02-08,Spin dynamics of a millisecond pulsar orbiting closely around a massive black hole,"We investigate the spin dynamics of a millisecond pulsar (MSP) in a tightly
bounded orbit around a massive black hole. These binaries are progenitors of
the extreme-mass-ratio-inspirals (EMRIs) and intermediate-mass-ratio-inspirals
(IMRIs) gravitational wave events. The Mathisson-Papapetrou-Dixon (MPD)
formulation is used to determine the orbital motion and spin modulation and
evolution. We show that the MSP will not be confined in a planar Keplerian
orbit and its spin will exhibit precession and nutation induced by spin-orbit
coupling and spin-curvature interaction. These spin and orbital behaviours will
manifest observationally in the temporal variations in the MSP's pulsed
emission and, with certain geometries, in the self-occultation of the pulsar's
emitting poles. Radio pulsar timing observations will be able to detect such
signatures. These extreme-mass-ratio binaries (EMRBs) and
intermediate-mass-ratio binaries (IMRBs) are also strong gravitational wave
sources. Combining radio pulsar timing and gravitational wave observations will
allow us to determine the dynamics of these systems in high precision and hence
the subtle behaviours of spinning masses in strong gravity.",1902.03146v1
2020-03-27,Electrical detection of unconventional transverse spin-currents in obliquely magnetized thin films,"In a typical experiment in magnonics, thin films are magnetized in-plane and
spin waves only carry angular momentum along their spatial propagation
direction. Motivated by the experiments of Bozhko et al. [Phys. Rev. Research
2, 023324 (2020)], we show theoretically that for obliquely magnetized thin
films, exchange-dipolar spin waves are accompanied by a transverse
spin-current. We propose an experiment to electrically detect this transverse
spin-current with Pt strips on top of a YIG film, by comparing the induced
spin-current for spin waves with opposite momenta. We predict the relative
difference to be of the order $10^{-4}$, for magnetic fields tilted at least
$30^{\circ}$ out of plane. This transverse spin-current is the result of the
long range dipole-dipole interaction and the inversion symmetry breaking of the
interface.",2003.12520v4
2021-02-20,Observation of Coherent Spin Waves in a Three-Dimensional Artificial Spin Ice Structure,"Harnessing high-frequency spin dynamics in three-dimensional (3D)
nanostructures may lead to paradigm-shifting, next generation devices including
high density spintronics and neuromorphic systems. Despite remarkable progress
in fabrication, the measurement and interpretation of spin dynamics in complex
3D structures remain exceptionally challenging. Here we take a first step and
measure coherent spin waves within a 3D artificial spin ice (ASI) structure
using Brillouin light scattering. The 3D-ASI was fabricated by using a
combination of two-photon lithography and thermal evaporation. Two spin-wave
modes were observed in the experiment whose frequencies showed a monotonic
variation with the applied field strength. Numerical simulations qualitatively
reproduced the observed modes. The simulated mode profiles revealed the
collective nature of the modes extending throughout the complex network of
nanowires while showing spatial quantization with varying mode quantization
numbers. The study shows a well-defined means to explore high-frequency spin
dynamics in complex 3D spintronic and magnonic structures.",2102.10270v1
2022-04-29,All-magnonic Stern-Gerlach effect in antiferromagnets,"The Stern-Gerlach (SG) effect is well known as the spin-dependent splitting
of a beam of atoms carrying magnetic moments by a magnetic-field gradient,
leading to the concept of electron spin. Antiferromagnets can accommodate two
magnon modes with opposite spin polarizations, which is equivalent to the spin
property of electrons. Here, we propose the existence of an all-magnonic SG
effect in antiferromagnetic magnonic system, where a linearly polarized
spin-wave beam is deflected by a straight Dzyaloshinskii-Moriya interaction
(DMI) interface into two opposite polarized spin-wave beams propagating in two
discrete directions. Moreover, we observe bi-focusing of antiferromagnetic spin
waves induced by a curved DMI interface, which can also spatially separate
thermal magnons with opposite polarizations. Our findings provide a unique
perspective to understand the rich phenomena associated with antiferromagnetic
magnon spin and would be helpful for polarization-dependent application of
antiferromagnetic spintronic devices.",2204.13942v1
2022-11-02,Spin wave excitations in a nanowire spin-torque oscillator with perpendicular magnetic anisotropy,"Spin torque oscillators (STOs) are emerging microwave devices that can
potentially be used in spin-logic devices and the next-generation high-speed
computing architecture. Thanks to their non-linear nature, STOs are easily
tunable by the magnetic field and the dc current. Spin Hall nano-oscillators
(SHNOs) are promising types of STOs and most of the current studies focus on
localized modes that can be easily excited. Here, we study using micromagnetic
simulations, the nature of the spin-torque-induced excitations in nanowire
devices made of perpendicular magnetic anisotropy (PMA) material. Our results
showed that upon including PMA the excitation of localized and propagating spin
wave modes is feasible. We study the nature of the mode excitations as a
function of the PMA strength (\text{K}$_u$), and the current. Indeed, we
estimate a critical value of \text{K}$_u$ to allow for the excitation of the
propagating spin wave. We attribute this mode selectivity between localized and
propagating modes to a switch in the sign of the nonlinearity of the system
from negative to positive at a non-zero \text{K}$_u$ which is supported by
analytical calculations. Our results provide deep insight into engineering
reconfigurable microwave devices for future magnonic and computational
applications.",2211.01078v1
2023-02-27,Spin Hall effects in the sky,"In many areas of physics, the propagation of wave packets carrying intrinsic
angular momentum is generally influenced by spin-orbit interactions. This is
the main mechanism behind spin Hall effects, which result in wave packets
following spin-dependent trajectories. Spin Hall effects have been observed in
several experiments for electrons in condensed matter systems and for light
propagating in inhomogeneous optical media. Similar effects have also been
predicted for wave packets propagating in inhomogeneous gravitational fields.
We give a brief introduction to gravitational spin Hall effects, emphasizing
the analogies with the spin Hall effect of light in optics. Furthermore, we
review the most promising astrophysical avenues that could lead to experimental
observations of the gravitational spin Hall effect.",2302.13634v2
2023-03-13,Coherent THz Spin Dynamics in Antiferromagnets Beyond the Approximation of the Néel vector,"Controlled generation of coherent spin waves with highest possible
frequencies and the shortest possible wavelengths is a cornerstone of
spintronics and magnonics. Here, using the Heisenberg antiferromagnet RbMF$_3$,
we demonstrate that laser-induced THz spin dynamics corresponding to pairs of
mutually coherent counter propagating spin waves with the wavevectors up to the
edge of the Brillouin zone cannot be understood in terms of magnetization and
antiferromagnetic (N\'eel) vectors, conventionally used to describe spin waves.
Instead, we propose to model such spin dynamics using the spin correlation
function. We derive a quantum-mechanical equation of motion for the latter and
emphasize that, unlike the magnetization and antiferromagnetic vectors the spin
correlations in antiferromagnets do not exhibit inertia.",2303.06996v4
2023-06-24,Causality and stability analysis for the minimal causal spin hydrodynamics,"We perform the linear analysis of causality and stability for a minimal
extended spin hydrodynamics up to second order of the gradient expansion. The
first order spin hydrodynamics, with a rank-3 spin tensor being antisymmetric
for only the last two indices, are proved to be acausal and unstable. We then
consider the minimal causal spin hydrodynamics up to second order of the
gradient expansion. We derive the necessary causality and stability conditions
for this minimal causal spin hydrodynamics. Interestingly, the satisfaction of
the stability conditions relies on the equations of state for the spin density
and chemical potentials. Moreover, different with the conventional relativistic
dissipative hydrodynamics, the stability of the theory seems to be broken at
the finite wave-vector when the stability conditions are fulfilled at small and
large wave-vector limits. It implies that the behavior in small and large
wave-vector limits may be insufficient to determine the stability conditions
for spin hydrodynamics in linear mode analysis.",2306.13880v3
2003-07-28,Non-magnetic semiconductor spin transistor,"We propose a spin transistor using only non-magnetic materials that exploits
the characteristics of bulk inversion asymmetry (BIA) in (110) symmetric
quantum wells. We show that extremely large spin splittings due to BIA are
possible in (110) InAs/GaSb/AlSb heterostructures, which together with the
enhanced spin decay times in (110) quantum wells demonstrates the potential for
exploitation of BIA effects in semiconductor spintronics devices. Spin
injection and detection is achieved using spin-dependent resonant interband
tunneling and spin transistor action is realized through control of the
electron spin lifetime in an InAs lateral transport channel using an applied
electric field (Rashba effect). This device may also be used as a spin valve,
or a magnetic field sensor. The electronic structure and spin relaxation times
for the spin transistor proposed here are calculated using a nonperturbative
14-band k.p nanostructure model.",0307687v1
2005-12-22,Theory of electric-field-induced spin accumulation and spin current in the two-dimensional Rashba model,"Based on the spin-density-matrix approach, both the electric-field-induced
spin accumulation and the spin current are systematically studied for the
two-dimensional Rashba model. Eigenmodes of spin excitations give rise to
resonances in the frequency domain. Utilizing a general and physically
well-founded definition of the spin current, we obtain results that differ
remarkably from previous findings. It is shown that there is a close
relationship between the spin accumulation and the spin current, which is due
to the prescription of a quasi-chemical potential and which does not result
from a conservation law. Physical ambiguities are removed that plagued former
approaches with respect to a spin-Hall current that is independent of the
electric field. For the clean Rashba model, the intrinsic spin-Hall
conductivity exhibits a logarithmic divergency in the low-frequency regime.",0512576v1
2007-07-31,Photon-assisted spin transport in a two-dimensional electron gas,"We study spin-dependent transport in a two-dimensional electron gas subject
to an external step-like potential $V(x)$ and irradiated by an electromagnetic
field (EF). In the absence of EF the electronic spectrum splits into spin
sub-bands originating from the ""Rashba"" spin-orbit coupling. We show that the
resonant interaction of propagating electrons with the component EF parallel to
the barrier induces a \textit{% non-equilibrium dynamic gap} $(2\Delta_{R})$
between the spin sub-bands. Existence of this gap results in coherent spin-flip
processes that lead to a spin-polarized current and a large magnetoresistance,
i.e the spin valve effect. These effects may be used for controlling spin
transport in semiconducting nanostructures, e.g. spin transistors,
spin-blockade devices etc., by variation of the intensity S and frequency
$\omega $ of the external radiation.",0707.4571v2
2009-11-13,Quantifying spin Hall angles from spin pumping: Experiments and Theory,"Spin Hall effects intermix spin and charge currents even in nonmagnetic
materials and, therefore, ultimately may allow the use of spin transport
without the need for ferromagnets. We show how spin Hall effects can be
quantified by integrating permalloy/normal metal (N) bilayers into a coplanar
waveguide. A dc spin current in N can be generated by spin pumping in a
controllable way by ferromagnetic resonance. The transverse dc voltage detected
along the permalloy/N has contributions from both the anisotropic
magnetoresistance (AMR) and the spin Hall effect, which can be distinguished by
their symmetries. We developed a theory that accounts for both. In this way, we
determine the spin Hall angle quantitatively for Pt, Au and Mo. This approach
can readily be adapted to any conducting material with even very small spin
Hall angles.",0911.2725v2
2011-07-02,Spin-pumping-induced spin transport in p-type Si at room temperature,"A spin battery concept is applied for the dynamical generation of pure spin
current and spin transport in p-type silicon (p-Si). Ferromagnetic resonance
and effective s-d coupling in Ni80Fe20 results in spin accumulation at the
Ni80Fe20/p-Si interface, inducing spin injection and the generation of spin
current in the p-Si. The pure spin current is converted to a charge current by
the inverse spin Hall effect of Pd evaporated onto the p-Si. This approach
demonstrates the generation and transport of pure spin current in p-Si at room
temperature.",1107.0376v4
2012-01-10,Quantum spin pumping mediated by magnon,"We theoretically propose quantum spin pumping mediated by magnons, under a
time-dependent transverse magnetic field, at the interface between a
ferromagnetic insulator and a non-magnetic metal. The generation of a spin
current under a thermal equilibrium condition is discussed by calculating the
spin transfer torque, which breaks the spin conservation law for conduction
electrons and operates the coherent magnon state. Localized spins lose spin
angular momentum by emitting magnons and conduction electrons flip from down to
up by absorbing the momentum. The spin transfer torque has a resonance
structure as a function of the angular frequency of the applied transverse
field. This fact is useful to enhance the spin pumping effect induced by
quantum fluctuations. We also discuss the distinction between our quantum spin
pumping theory and the one proposed by Tserkovnyak et al.",1201.1947v3
2013-02-18,Comparative Measurements of Inverse Spin Hall and Magnetoresistance in YIG|Pt and YIG|Ta,"We report on a comparative study of spin Hall related effects and
magnetoresistance in YIG|Pt and YIG|Ta bilayers. These combined measurements
allow to estimate the characteristic transport parameters of both Pt and Ta
layers juxtaposed to YIG: the spin mixing conductance $G_{\uparrow \downarrow}$
at the YIG$|$normal metal interface, the spin Hall angle $\Theta_{SH}$, and the
spin diffusion length $\lambda_{sd}$ in the normal metal. The inverse spin Hall
voltages generated in Pt and Ta by the pure spin current pumped from YIG
excited at resonance confirm the opposite signs of spin Hall angles in these
two materials. Moreover, from the dependence of the inverse spin Hall voltage
on the Ta thickness, we extract the spin diffusion length in Ta, found to be
$\lambda_{sd}^\text{Ta}=1.8\pm0.7$ nm. Both the YIG|Pt and YIG|Ta systems
display a similar variation of resistance upon magnetic field orientation,
which can be explained in the recently developed framework of spin Hall
magnetoresistance.",1302.4416v1
2013-10-17,Electrical Detection of Direct and Alternating Spin Current Injected from a Ferromagnetic Insulator into a Ferromagnetic Metal,"We report room temperature electrical detection of spin injection from a
ferromagnetic insulator (YIG) into a ferromagnetic metal (Permalloy, Py).
Non-equilibrium spins with both static and precessional spin polarizations are
dynamically generated by the ferromagnetic resonance of YIG magnetization, and
electrically detected by Py as dc and ac spin currents, respectively. The dc
spin current is electrically detected via the inverse spin Hall effect of Py,
while the ac spin current is converted to a dc voltage via the spin
rectification effect of Py which is resonantly enhanced by dynamic exchange
interaction between the ac spin current and the Py magnetization. Our results
reveal a new path for developing insulator spintronics, which is distinct from
the prevalent but controversial approach of using Pt as the spin current
detector.",1310.4840v1
2013-12-10,Spin Pumping and Inverse Spin Hall Effect in Platinum: The Essential Role of Spin-Memory Loss at Metallic Interfaces,"Through combined ferromagnetic resonance, spin-pumping and inverse spin Hall
effect experiments in Co|Pt bilayers and Co|Cu|Pt trilayers, we demonstrate
consistent values of spin diffusion length $\ell_{\rm sf}^{\rm Pt}=3.4\pm0.4$
nm and of spin Hall angle $\theta_{\rm SHE}^{\rm Pt}=0.051\pm0.004$ for Pt. Our
data and model emphasize on the partial depolarization of the spin current at
each interface due to spin-memory loss. Our model reconciles the previously
published spin Hall angle values and explains the different scaling lengths for
the ferromagnetic damping and the spin Hall effect induced voltage.",1312.2717v2
2014-03-12,Spin Gap in the Single Spin-1/2 Chain Cuprate Sr$_{1.9}$Ca$_{0.1}$CuO$_3$,"We report $^{63}$Cu nuclear magnetic resonance and muon spin rotation
measurements on the S=1/2 antiferromagnetic Heisenberg spin chain compound
Sr$_{1.9}$Ca$_{0.1}$CuO$_3$. An exponentially decreasing spin-lattice
relaxation rate 1/T$_1$ indicates the opening of a spin gap. This behavior is
very similar to what has been observed for the cognate zigzag spin chain
compound Sr$_{0.9}$Ca$_{0.1}$CuO$_2$, and confirms that the occurrence of a
spin gap upon Ca doping is independent of the interchain exchange coupling
$J'$. Our results therefore generally prove the appearance of a spin gap in an
antiferromagnetic Heisenberg spin chain induced by a local bond disorder of the
intrachain exchange coupling $J$. A low temperature upturn of 1/T$_1$ evidences
growing magnetic correlations. However, zero field muon spin rotation
measurements down to 1.5 K confirm the absence of magnetic order in this
compound which is most likely suppressed by the opening of the spin gap.",1403.2890v1
2015-09-13,Coherent coupling of a single spin to microwave cavity photons,"Electron spins and photons are complementary quantum-mechanical objects that
can be used to carry, manipulate and transform quantum information. To combine
these resources, it is desirable to achieve the coherent coupling of a single
spin to photons stored in a superconducting resonator. Using a circuit design
based on a nanoscale spin-valve, we coherently hybridize the individual spin
and charge states of a double quantum dot while preserving spin coherence. This
scheme allows us to achieve spin-photon coupling up to the MHz range at the
single spin level. The cooperativity is found to reach 2.3, and the spin
coherence time is about 60ns. We thereby demonstrate a mesoscopic device
suitable for non-destructive spin read-out and distant spin coupling.",1509.03839v1
2015-12-15,Moderate Positive Spin Hall Angle in Uranium,"We report measurements of spin pumping and the inverse spin Hall effect in
Ni80Fe20/Uranium bilayers designed to study the efficiency of spin-charge
interconversion in a super-heavy element. We employ broad-band ferromagnetic
resonance on extended films to inject a spin current from the Ni80Fe20
(permalloy) into the uranium layer, which is then converted into an electric
field by the inverse spin Hall effect. Surprisingly, our results suggest a spin
mixing conductance of order 2x10 e19 m-2 and a positive spin Hall angle of
0.004, which are both merely comparable to those of several transition metals.
These results thus support the idea that the electronic configuration may be at
least as important as the atomic number in governing spin pumping across
interfaces and subsequent spin Hall effects. In fact, given that both the
magnitude and the sign are unexpected based on trends in d-electron systems,
materials with unfilled f-electron orbitals may hold additional exploration
avenues for spin physics.",1512.04903v1
2018-05-15,Spin-orbit effects on the spin and pseudospin polarization in ac-driven silicene,"We study the pseudospin and spin dynamical effects in single-layer silicene
due to a perpendicular electric field periodically driven and its interplay
with the intrinsic and extrinsic (Rashba) spin-orbit interaction. We find that
the spin nonconserving processes of the real spin of the quasiparticles in
silicene, -- induced by the rather weak spin-orbit mechanisms --, manifest
themselves as shifts of the resonances of its quasienergy spectrum in the low
coupling regime to the driving field. We show that there is an interesting
cooperative effect among the, in principle, competing Rashba and intrinsic
spin-orbit contributions. This is explicitly illustrated by exact and
approximated analytical solutions of the dynamical equations. In addition, we
show that a finite Rashba spin-orbit interaction is indeed necessary in order
to achieve a nonvanishing spin polarization. As additional feature, trivial and
nontrivial topological phases might be distinguished from each other as fast or
slow dynamical fluctuations of the spin polarization. We mention the possible
experimental detection schemes of our theoretical results and their relevance
in new practical implementation of periodically driven interactions in silicene
physics and related two-dimensional systems.",1805.05833v1
2018-06-06,Control of magnetization dynamics by spin Nernst torque,"Control of magnetization dynamics is one of the primary goals in spintronics.
It has been demonstrated using spin Hall effect i.e charge current to spin
current conversion in non-magnetic metal which has large spin-orbit coupling
such as Pt, W etc. Recently different groups have shown generation of spin
current in Pt, W while thermal gradient is created by virtue of spin Nernst
effect. In this work we show the evidence of magnetization control by spin
Nernst torque in Pt/Py bi-layer. We compared relative strength of spin Nernst
Torque and spin Hall torque by measuring the systematic variation of magnetic
linewidth on application of constant heat or charge current. Spin-torque
ferromagnetic resonance (ST-FMR) technique is adopted to excite the magnet and
to measure line-width precisely from the symmetric and anti-symmetric voltage
component. Control of magnetization dynamics by spin Nernst torque will emerge
as an alternative way to manipulate nano-magnets.",1806.01978v1
2019-11-22,"Confinement, reduced entanglement, and spin-glass order in a random quantum spin-ice model","We study an effective spin model derived perturbatively from random
transverse-field Ising model on the pyrochlore lattice. The model consists of
spin-configurations on the pyrochlore lattice, restricted to the spin-ice
subspace, with spins interacting with random Ising exchange couplings as well
as ring exchanges along the hexagons of the lattice. This model is studied by
exact diagonalization upto N=64 site systems. We calculate spin-glass
correlation functions and local entanglement entropy $S_T$ between spins in a
single tetrahedron and the rest of the system. We find that the model undergoes
two phase transitions. At weak randomness the model is in a quantum spin-ice
phase where $S_T=\ln{6}$. Increasing randomness first leads to a frozen phase,
with long-range spin-glass order and $S_T=\ln{2}$ corresponding to the Cat
states associated with Ising order. Further increase in randomness leads to a
random resonating-hexagon phase with a frozen backbone of spins and a broad
distribution of entanglement entropies. The implications of these studies for
non-Kramers rare-earth pyrochlores are discussed.",1911.10243v1
2019-06-12,Quantum memory assisted precision rotation sensing,"We propose to implement a solid-state rotation sensor by employing a
many-body quantum spin system which takes the advantages of the easy
controllability of the electron spin and the robustness provided by the
collective nuclear spin state. The sensor consists of a central electron spin
coupled to many surrounding nuclear spins. Previously, this central spin system
has been suggested to realize a quantum memory. Here, we further utilize the
collective nuclear spins, which store a certain quantum state, to detect the
macroscopic rotation. Different from other nuclear spin-based gyroscopes, our
proposal does not directly manipulate nuclear spins via nuclear magnetic
resonance technique. We analytically and numerically investigate the effects of
partial nuclear polarization and decoherence on the sensitivity. We also
briefly introduce the procedure to generate entanglement between nuclear spins
through the quantum memory technique and to utilize this entanglement to
enhance the sensing performance. Our proposal paves the way to the experimental
realization of a compact solid-state, full-electrical and spin-based gyroscope.",1906.04995v3
2019-03-26,Nuclear spin assisted quantum tunnelling of magnetic monopoles in spin ice,"Extensive work on single molecule magnets has identified a fundamental mode
of relaxation arising from the nuclear-spin assisted quantum tunnelling of
nearly independent and quasi-classical magnetic dipoles. Here we show that
nuclear-spin assisted quantum tunnelling can also control the dynamics of
purely emergent excitations: magnetic monopoles in spin ice. Our low
temperature experiments were conducted on canonical spin ice materials with a
broad range of nuclear spin values. By measuring the magnetic relaxation, or
monopole current, we demonstrate strong evidence that dynamical coupling with
the hyperfine fields bring the electronic spins associated with magnetic
monopoles to resonance, allowing the monopoles to hop and transport magnetic
charge. Our result shows how the coupling of electronic spins with nuclear
spins may be used to control the monopole current. It broadens the relevance of
the assisted quantum tunnelling mechanism from single molecular spins to
emergent excitations in a strongly correlated system.",1903.11122v1
2021-08-13,Long-Lived Spin-Polarized Intermolecular Exciplex States in Thermally Activated Delayed Fluorescence-Based Organic Light-Emitting Diodes,"Spin-spin interactions in organic light-emitting diodes (OLEDs) based on
thermally activated delayed fluorescence (TADF) are pivotal because radiative
recombination is largely determined by triplet-to-singlet conversion, also
called reverse intersystem crossing (RISC). To explore the underlying process,
we apply a spin-resonance spectral hole-burning technique to probe
electroluminescence. We find that the triplet exciplex states in OLEDs are
highly spin-polarized and show that these states can be decoupled from the
heterogeneous nuclear environment as a source of spin dephasing and can even be
coherently manipulated on a spin-spin relaxation time scale T2* of 30 ns.
Crucially, we obtain the characteristic triplet exciplex spin-lattice
relaxation time T1 in the range of 50 us, which far exceeds the RISC time. We
conclude that slow spin relaxation rather than RISC is an efficiency-limiting
step for intermolecular donor:acceptor systems. Finding TADF emitters with
faster spin relaxation will benefit this type of TADF OLEDs.",2108.06323v2
2017-01-05,Coherent long-distance displacement of individual electron spins,"Controlling nanocircuits at the single electron spin level is a possible
route for large-scale quantum information processing. In this context,
individual electron spins have been identified as versatile quantum information
carriers to interconnect different nodes of a spin-based semiconductor quantum
circuit. Despite important experimental efforts to control the electron
displacement over long distances, keeping the electron spin coherence after
transfer remained up to now elusive. Here we demonstrate that individual
electron spins can be displaced coherently over a distance of 5 micrometers.
This displacement is realized on a closed path made of three tunnel-coupled
lateral quantum dots. Using fast quantum dot control, the electrons tunnel from
one dot to another at a speed approaching 100 m/s. We find that the spin
coherence length is 8 times longer than expected from the electron spin
coherence without displacement. Such an enhanced spin coherence points at a
process similar to motional narrowing observed in nuclear magnetic resonance
experiments6. The demonstrated coherent displacement will enable long-range
interaction between distant spin-qubits and will open the route towards
non-abelian and holonomic manipulation of a single electron spin.",1701.01279v1
2017-04-13,Spin pumping into superconductors: A new probe of spin dynamics in a superconducting thin film,"Spin pumping refers to the microwave-driven spin current injection from a
ferromagnet into the adjacent target material. We theoretically investigate the
spin pumping into superconductors by fully taking account of impurity
spin-orbit scattering that is indispensable to describe diffusive spin
transport with finite spin diffusion length. We calculate temperature
dependence of the spin pumping signal and show that a pronounced coherence peak
appears immediately below the superconducting transition temperature Tc, which
survives even in the presence of the spin-orbit scattering. The phenomenon
provides us with a new way of studying the dynamic spin susceptibility in a
superconducting thin film. This is contrasted with the nuclear magnetic
resonance technique used to study a bulk superconductor.",1704.04303v2
2020-06-14,Spin-orbit torque generated by amorphous Fe$_{x}$Si$_{1-x}$,"While tremendous work has gone into spin-orbit torque and spin current
generation, charge-to-spin conversion efficiency remains weak in silicon to
date, generally stemming from the low spin-orbit coupling (low atomic number,
Z) and lack of bulk lattice inversion symmetry breaking. Here we report the
observation of spin-orbit torque in an amorphous, non-ferromagnetic
Fe$_{x}$Si$_{1-x}$ / cobalt bilayer at room temperature, using spin torque
ferromagnetic resonance and harmonic Hall measurements. Both techniques provide
a minimum spin torque efficiency of about 3 %, comparable to prototypical heavy
metals such as Pt or Ta. According to the conventional theory of the spin Hall
effect, a spin current in an amorphous material is not expected to have any
substantial contribution from the electronic bandstructure. This, combined with
the fact that Fe$_{x}$Si$_{1-x}$ does not contain any high-Z element, paves a
new avenue for understanding the underlying physics of spin-orbit interaction
and opens up a new class of material systems - silicides - that is directly
compatible with complementary metal-oxide-semiconductor (CMOS) processes for
integrated spintronics applications.",2006.07786v1
2020-10-29,Theory of optically detected spin noise in nanosystems,"Theory of spin noise in low dimensional systems and bulk semiconductors is
reviewed. Spin noise is usually detected by optical means, continuously
measuring the rotation angle of the polarization plane of the probe beam
passing through the sample. Spin noise spectra yield rich information about the
spin properties of the system including, for example, $g$-factors of the charge
carriers, spin relaxation times, parameters of the hyperfine interaction,
spin-orbit interaction constants, frequencies and widths of the optical
resonances. The review describes basic models of spin noise, methods of its
theoretical description, and their relation with the experimental results. We
also discuss the relation between the spin noise spectroscopy, the strong and
weak quantum measurements and the spin flip Raman scattering, and analyze
similar effects including manifestations of the charge, current and valley
polarization fluctuations in the optical response. Possible directions for
further development of the spin noise spectroscopy are outlined.",2010.15763v1
2021-06-26,Spin current injection via equal-spin Cooper pairs in ferromagnet/superconductor heterostructures,"Equal-spin Cooper pairs are pivotal building blocks for superconducting
spintronics devices. In recent experiments, unusual behavior was observed in
ferromagnet/ferromagnet/superconductor devices when a precession of the
magnetization was induced by ferromagnetic resonance. By using a
non-equilibrium Usadel Green function formalism, we study spin transport for
such a setup. We solve for spin-resolved distribution functions and demonstrate
that the spin injection process in superconductors is governed by the inverse
proximity effect in the superconducting layer. We find that equal-spin Cooper
pairs, which are produced by the two misaligned ferromagnetic layers, transport
spin inside the S layer. This then results in an increase of the injected spin
current below the superconducting critical temperature. Our calculations
provide the first evidence of the essential role of equal-spin Cooper pairs on
spin-transport properties of S/F devices and pave new avenues for the design of
superconducting spintronics devices.",2106.13988v3
2022-03-10,Extending the spin excitation lifetime of a magnetic molecule on a proximitized superconductor,"Magnetic molecules deposited on surfaces are a promising platform to
individually address and manipulate spins. Long spin excitation lifetimes are
necessary to utilize them in quantum information processing and data storage.
Normally, coupling of the molecular spin with the conduction electrons of
metallic surfaces causes fast relaxation of spin excitations into the ground
state. However, the presence of superconducting paring effects in the substrate
can protect the excited spin from decaying. In this work, we show that a
proximity-induced superconducting gold film can sustain spin excitations of a
FeTPP-Cl molecule for more than 80ns. This long value was determined by
studying inelastic spin excitations of the S=5/2 multiplet of FeTPP-Cl on Au
films over V(100) using scanning tunneling spectroscopy. The spin lifetime
decreases with increasing film thickness, in apparent connection with the
gradual gap-closing of a pair of de Gennes-Saint James resonances found inside
the superconducting gap. Our results elucidate the use of proximitized gold
electrodes for addressing quantum spins on surfaces, envisioning new routes for
tuning the value of their spin lifetime.",2203.05613v1
2022-06-14,Possible Coexistence of Antiferromagnetic and Ferromagnetic Spin Fluctuations in the Spin-triplet Superconductor UTe2 Revealed by 125Te NMR under Pressure,"A spin-triplet superconducting state mediated by ferromagnetic (FM) spin
fluctuations has been suggested to occur in the newly discovered heavy-fermion
superconductor UTe$_2$. However, the recent neutron scattering measurements
revealed the presence of antiferromagnetic (AFM) spin fluctuations in UTe$_2$.
Here, we report the $^{125}$Te nuclear magnetic resonance (NMR) studies of a
single-crystal UTe$_2$, suggesting the coexistence of FM and AFM spin
fluctuations in UTe$_2$. Owing to the two different Te sites in the compound,
we conclude that the FM spin fluctuations are dominant within ladders and the
AFM spin fluctuations originate from the inter-ladder magnetic coupling.
Although AFM spin fluctuations exist in the system, the FM spin fluctuations in
the ladders may play an important role in the appearance of the spin-triplet
superconducting state of UTe$_2$.",2206.06893v1
2023-10-27,Ultrafast switchable spin-orbit coupling for silicon spin qubits via spin valves,"Recent experimental breakthroughs, particularly for single-qubit and
two-qubit gates exceeding the error correction threshold, highlight silicon
spin qubits as leading candidates for fault-tolerant quantum computation. In
the existing architecture, intrinsic or synthetic spin-orbit coupling (SOC) is
critical in various aspects, including electrical control, addressability,
scalability, etc. However, the high-fidelity SWAP operation and quantum state
transfer (QST) between spin qubits, crucial for qubit-qubit connectivity,
require the switchable nature of SOC which is rarely considered. Here, we
propose a flexible architecture based on spin valves by electrically changing
its magnetization orientation within sub-nanoseconds to generate ultrafast
switchable SOC. Based on the switchable SOC architecture, both SWAP operation
of neighbor spin qubits and resonant QST between distant spins can be realized
with fidelity exceeding 99% while considering the realistic experimental
parameters. Benefiting from the compatible processes with the modern
semiconductor industry and experimental advances in spin valves and spin
qubits, our results pave the way for future construction of silicon-based
quantum chips.",2310.17993v1
2024-02-12,Blueprint for efficient nuclear spin characterization with color center,"Nuclear spins in solids offer a promising avenue for developing scalable
quantum hardware. Leveraging nearby single-color centers, these spins can be
efficiently addressed at the single-site level through spin resonance. However,
characterising individual nuclear spins is quite cumbersome since the
characterisation protocols may differ depending on the strength of the
hyperfine coupling, necessitating tailored approaches and experimental
conditions. While modified electron spin Hahn echoes like CPMG and XY8 pulse
sequences are commonly employed, they encounter significant limitations in
scenarios involving spin-1/2 systems, strongly coupled spins, or nuclear spin
baths comprising distinct isotopes. Here, we present a more straightforward
approach for determining the hyperfine interactions among each nuclear and the
electron spin. This method holds promise across diverse platforms, especially
for emerging S=1/2 group IV defects in diamond (e.g., SiV, GeV, SnV, PbV) or
silicon (T-centre, P-donors). We provide a theoretical framework and adapt it
for color-centers exhibiting various spins. Through simulations conducted on
nuclear spin clusters, we evaluate different protocols and compare their
performance using the Fisher information matrix and Cramer Rao bounds.",2402.08107v1
1999-01-19,"Collisionless Dissipative Nonlinear Alfven Waves: Nonlinear Steepening, Compressible Turbulence, and Particle Trapping","The magnetic energy of nonlinear Alfven waves in compressible plasmas may be
ponderomotively coupled only to ion-acoustic quasi-modes which modulate the
wave phase velocity and cause wave-front steepening. In the collisionless
plasma with $\beta\not=0$, the dynamics of nonlinear Alfven wave is also
affected by the resonant particle-wave interactions. Upon relatively rapid
evolution (compared to the particle bounce time), the quasi-stationary wave
structures, identical to the so called (Alfvenic) Rotational Discontinuities,
form, the emergence and dynamics of which has not been previously understood.
Collisionless (Landau) dissipation of nonlinear Alfven waves is also a
plausible and natural mechanism of the solar wind heating. Considering a
strong, compressible, Alfvenic turbulence as an ensemble of randomly
interacting Alfvenic discontinuities and nonlinear waves, it is shown that
there exist two distinct phases of turbulence. What phase realizes depends on
whether this collisionless damping is strong enough to provide adequate energy
sink at all scales and, thus, to support a steady-state cascade of the wave
energy. In long-time asymptotics, however, the particle distribution function
is affected by the wave magnetic fields. In this regime of nonlinear Landau
damping, resonant particles are trapped in the quasi-stationary Alfvenic
discontinuities, giving rise to a formation of a plateau on the distribution
function and quenching collisionless damping. Using the virial theorem for
trapped particles, it is analytically demonstrated that their effect on the
nonlinear dynamics of such discontinuities is non-trivial and forces a
significant departure of the theory from the conventional paradigm.",9901257v1
2006-11-08,Equilibrium statistical mechanics for single waves and wave spectra in Langmuir wave-particle interaction,"Under the conditions of weak Langmuir turbulence, a self-consistent
wave-particle Hamiltonian models the effective nonlinear interaction of a
spectrum of M waves with N resonant out-of-equilibrium tail electrons. In order
to address its intrinsically nonlinear time-asymptotic behavior, a Monte Carlo
code was built to estimate its equilibrium statistical mechanics in both the
canonical and microcanonical ensembles. First the single wave model is
considered in the cold beam/plasma instability and in the O'Neil setting for
nonlinear Landau damping. O'Neil's threshold, that separates nonzero
time-asymptotic wave amplitude states from zero ones, is associated to a second
order phase transition. These two studies provide both a testbed for the Monte
Carlo canonical and microcanonical codes, with the comparison with exact
canonical results, and an opportunity to propose quantitative results to
longstanding issues in basic nonlinear plasma physics. Then the properly
speaking weak turbulence framework is considered through the case of a large
spectrum of waves. Focusing on the small coupling limit, as a benchmark for the
statistical mechanics of weak Langmuir turbulence, it is shown that Monte Carlo
microcanonical results fully agree with an exact microcanonical derivation. The
wave spectrum is predicted to collapse towards small wavelengths together with
the escape of initially resonant particles towards low bulk plasma thermal
speeds. This study reveals the fundamental discrepancy between the long-time
dynamics of single waves, that can support finite amplitude steady states, and
of wave spectra, that cannot.",0611082v1
2017-12-28,Coexistence of weak and strong wave turbulence in incompressible Hall magnetohydrodynamics,"We report a numerical investigation of three dimensional, incompressible,
Hall magnetohydrodynamic turbulence with a relatively strong mean magnetic
field. Using helicity decomposition and cross-bicoherence analysis, we observe
that the resonant three--wave coupling is substantial among ion cyclotron and
whistler waves. A detailed study of the degree of non-linearity of these two
populations shows that the ion cyclotron component experiences a transition
from weak to strong wave turbulence going from large to small scales, while the
whistler fluctuations display a weak wave turbulence character for all scales.
This non-trivial coexistence of the two regimes with the two populations of
waves gives rise to anomalous anisotropy and scaling properties. The weak and
strong wave turbulence components can be distinguished rather efficiently using
spatio-temporal Fourier transforms. The analysis shows that while resonant
triadic interactions survive the highly non-linear bath of ion cyclotron
fluctuations at large scales for which the degree of non-linearity is low for
both populations of waves, whistler waves tend to be killed by the non-linear
cross-coupling at smaller scales where the ion cyclotron component is in the
strong wave turbulent regime. Such situation may have far-reaching implications
for the physics of magnetized turbulence in many astrophysical and space
plasmas where different waves coexist and compete to transfer non-linearly
energy across scales.",1712.10002v1
2020-05-21,General rogue waves in the three-wave resonant interaction systems,"General rogue waves in (1+1)-dimensional three-wave resonant interaction
systems are derived by the bilinear method. These solutions are divided into
three families, which correspond to a simple root, two simple roots and a
double root of a certain quartic equation arising from the dimension reduction
respectively. It is shown that while the first family of solutions associated
with a simple root exist for all signs of the nonlinear coefficients in the
three-wave interaction equations, the other two families of solutions
associated with two simple roots and a double root can only exist in the
so-called soliton-exchange case, where the nonlinear coefficients have certain
signs. Many of these rogue wave solutions, such as those associated with two
simple roots, and higher-order solutions associated with a simple root, are new
solutions which have not been reported before. Technically, our bilinear
derivation of rogue waves for the double-root case is achieved by a
generalization to the previous dimension reduction procedure in the bilinear
method, and this generalized procedure allows us to treat roots of arbitrary
multiplicities. Dynamics of the derived rogue waves is also examined, and new
rogue-wave patterns are presented. Connection between these bilinear rogue
waves and those derived earlier by Darboux transformation is also explained.",2005.10847v2
2023-05-24,Faraday Waves in Bose-Einstein Condensates -- The Excitation by the Modulation of the Interaction and the Potential,"We numerically study the dynamics of Faraday waves for Bose-Einstein
condensates(BECs) trapped by anisotropic potentials using the three-dimensional
Gross-Pitaevskii equation. In previous studies, Faraday waves were excited by
periodic modulation of the interaction or potential; in contrast, this study
systematically addresses the excitations of the two methods. When the
interaction is modulated with a modulation frequency resonant with Faraday
waves, the breathing mode along the tight confinement direction is excited, and
the Faraday waves appear in the direction of weak confinement. A modulation
frequency that is not resonant with Faraday waves does not excite Faraday
waves. Thus, the dynamics depend on modulation frequencies. The behavior of the
total energy and its decomposition characterize the dynamics. The excitation of
Faraday waves depends on the anisotropy of the potentials as well; Faraday
waves are excited only for elongated BECs. We compare the differences of the
dynamics in modulation methods. There are no qualitative differences between
the modulation of the interaction and potential. When the interaction and
potential are simultaneously modulated, Faraday waves are excited but they do
not necessarily work additively. To understand this phenomenon as a dynamical
system, we choose a few dynamical variables and follow their trajectory in a
phase space. The trajectory characteristics of Faraday waves and the breathing
mode show that the methods of modulation are not very relevant; determining the
target mode to excite is important.",2305.14729v1
2007-08-01,Spin measurements for 147Sm+n resonances: Further evidence for non-statistical effects,"We have determined the spins J of resonances in the 147Sm(n,gamma) reaction
by measuring multiplicities of gamma-ray cascades following neutron capture.
Using this technique, we were able to determine J values for all but 14 of the
140 known resonances below En = 1 keV, including 41 firm J assignments for
resonances whose spins previously were either unknown or tentative. These new
spin assignments, together with previously determined resonance parameters,
allowed us to extract separate level spacings and neutron strength functions
for J = 3 and 4 resonances. Furthermore, several statistical test of the data
indicate that very few resonances of either spin have been missed below En =
700eV. Because a non-statistical effect recently was reported near En = 350 eV
from an analysis of 147Sm(n,alpha) data, we divided the data into two regions;
0 < En < 350 eV and 350 < En < 700 eV. Using neutron widths from a previous
measurement and published techniques for correcting for missed resonances and
for testing whether data are consistent with a Porter-Thomas distribution, we
found that the reduced-neutron-width distribution for resonances below 350 eV
is consistent with the expected Porter-Thomas distribution. On the other hand,
we found that reduced-neutron-width data in the 350 < En < 700 eV region are
inconsistent with a Porter-Thomas distribution, but in good agreement with a
chi-squared distribution having two or more degrees of freedom. We discuss
possible explanations for these observed non-statistical effects and their
possible relation to similar effects previously observed in other nuclides.",0708.0218v1
1995-12-13,Memory Loss and Auger Processes in a Many Body Theory of Charge Transfer,"Charge transfer between hyperthermal alkali atoms and metallic scattering
surfaces is an experimental and theoretical arena for many-body interactions.
To model new facets, we use a generalized time-dependent Newns-Anderson
Hamiltonian which includes electron spin, multiple atomic orbitals with image
shifted levels, intra-atomic Coulomb repulsion, and resonant exchange. A
variational electronic many-body wave function solves the dynamical problem.
The wave function consists of sectors with either zero or one particle-hole
pair and goes beyond earlier work through the inclusion of amplitudes for a
neutral atom plus an electron-hole pair. Higher order sectors with more than
one particle-hole pair are suppressed by powers of $1/N$; hence the wave
function ansatz is equivalent to a $1/N$ expansion. The equations of motion are
integrated numerically without further approximation. The solution shows
improved loss-of-memory -- the final charge state is independent of the initial
one -- in agreement with theoretical and experimental expectations.
Understanding of this phenomenon is deepened through an analysis of entropy
production. By studying the independent-particle approximation, and by
examining the role played by different sectors of the Hilbert space in entropy
production, we arrive at necessary and sufficient conditions for loss-of-memory
to occur in the many-body solution. As further tests of the theory, we
reproduce the experimentally observed peak in the excited neutral Li(2p)
occupancy at intermediate work functions starting from different initial
conditions. Next, we include Auger processes by adding two-body interaction
terms to the many-body Hamiltonian. Several types of Auger processes are
considered, and these are shown to affect the final state occupancies at low",9512102v1
2011-09-02,New Kludge Scheme for the Construction of Approximate Waveforms for Extreme-Mass-Ratio Inspirals,"We introduce a new kludge scheme to model the dynamics of generic extreme
mass-ratio inspirals (stellar compact objects spiraling into a spinning
supermassive black hole) and to produce the gravitational waveforms that
describe the gravitational-wave emission of these systems. This scheme combines
tools from different techniques in General Relativity: It uses a multipolar,
post-Minkowskian (MPM) expansion for the far-zone metric perturbation (which
provides the gravitational waveforms, here taken up to mass hexadecapole and
current octopole order) and for the local prescription of the self-force (since
we are lacking a general prescription for it); a post-Newtonian expansion for
the computation of the multipole moments in terms of the trajectories; and a BH
perturbation theory expansion when treating the trajectories as a sequence of
self-adjusting Kerr geodesics. The orbital evolution is thus equivalent to
solving the geodesic equations with time-dependent orbital elements, as
dictated by the MPM radiation-reaction prescription. To complete the scheme,
both the orbital evolution and wave generation require to map the
Boyer-Lindquist coordinates of the orbits to the harmonic coordinates in which
the different MPM quantities have been derived, a mapping that we provide
explicitly in this paper. This new kludge scheme is thus a combination of
approximations that can be used to model generic inspirals of systems with
extreme mass ratios to systems with more moderate mass ratios, and hence can
provide valuable information for future space-based gravitational-wave
observatories like LISA and even for advanced ground detectors. Finally, due to
the local character in time of our MPM self-force, this scheme can be used to
perform studies of the possible appearance of transient resonances in generic
inspirals.",1109.0572v2
2012-01-27,Approximate Waveforms for Extreme-Mass-Ratio Inspirals: The Chimera Scheme,"We describe a new kludge scheme to model the dynamics of generic
extreme-mass-ratio inspirals (EMRIs; stellar compact objects spiraling into a
spinning supermassive black hole) and their gravitational-wave emission. The
Chimera scheme is a hybrid method that combines tools from different
approximation techniques in General Relativity: (i) A multipolar,
post-Minkowskian expansion for the far-zone metric perturbation (the
gravitational waveforms) and for the local prescription of the self-force; (ii)
a post-Newtonian expansion for the computation of the multipole moments in
terms of the trajectories; and (iii) a BH perturbation theory expansion when
treating the trajectories as a sequence of self-adjusting Kerr geodesics. The
EMRI trajectory is made out of Kerr geodesic fragments joined via the method of
osculating elements as dictated by the multipolar post-Minkowskian
radiation-reaction prescription. We implemented the proper coordinate mapping
between Boyer-Lindquist coordinates, associated with the Kerr geodesics, and
harmonic coordinates, associated with the multipolar post-Minkowskian
decomposition. The Chimera scheme is thus a combination of approximations that
can be used to model generic inspirals of systems with extreme to intermediate
mass ratios, and hence, it can provide valuable information for future
space-based gravitational-wave observatories, like LISA, and even for advanced
ground detectors. The local character in time of our multipolar
post-Minkowskian self-force makes this scheme amenable to study the possible
appearance of transient resonances in generic inspirals.",1201.5715v1
2020-02-18,TurboRVB: a many-body toolkit for {\it ab initio} electronic simulations by quantum Monte Carlo,"TurboRVB is a computational package for {\it ab initio} Quantum Monte Carlo
(QMC) simulations of both molecular and bulk electronic systems. The code
implements two types of well established QMC algorithms: Variational Monte
Carlo (VMC), and Diffusion Monte Carlo in its robust and efficient lattice
regularized variant. A key feature of the code is the possibility of using
strongly correlated many-body wave functions. The electronic wave function (WF)
is obtained by applying a Jastrow factor, which takes into account dynamical
correlations, to the most general mean-field ground state, written either as an
antisymmetrized geminal product with spin-singlet pairing, or as a Pfaffian,
including both singlet and triplet correlations. This wave function can be
viewed as an efficient implementation of the so-called resonating valence bond
(RVB) ansatz, first proposed by L. Pauling and P. W. Anderson in quantum
chemistry and condensed matter physics, respectively. The RVB ansatz
implemented in TurboRVB has a large variational freedom, including the Jastrow
correlated Slater determinant as its simplest, but nontrivial case. Moreover,
it has the remarkable advantage of remaining with an affordable computational
cost, proportional to the one spent for the evaluation of a single Slater
determinant. The code implements the adjoint algorithmic differentiation that
enables a very efficient evaluation of energy derivatives, comprising the ionic
forces. Thus, one can perform structural optimizations and molecular dynamics
in the canonical NVT ensemble at the VMC level. For the electronic part, a full
WF optimization is made possible thanks to state-of-the-art stochastic
algorithms for energy minimization. The code has been efficiently parallelized
by using a hybrid MPI-OpenMP protocol, that is also an ideal environment for
exploiting the computational power of modern GPU accelerators.",2002.07401v2
2009-12-28,Wave-Particle Duality and the Hamilton-Jacobi Equation,"The Hamilton-Jacobi equation of relativistic quantum mechanics is revisited.
The equation is shown to permit solutions in the form of breathers
(oscillating/spinning solitons), displaying simultaneous particle-like and
wave-like behavior. The de Broglie wave thus acquires a clear deterministic
meaning of a wave-like excitation of the classical action function. The problem
of quantization in terms of the breathing action function and the double-slit
experiment are discussed.",0912.5156v1
2016-01-05,Spinning swimming of Volvox by tangential helical wave,"The swimming of a sphere by means of tangential helical waves running along
its surface is studied on the basis of the Stokes equations. Two types of
tangential waves are found. The first of these is associated with a pressure
disturbance and leads to a higher rate of net rotation than the second one for
the same power. It is suggested that the helical waves are relevant for the
rotational swimming of Volvox.",1601.00755v1
2006-11-13,Doping dependance of the spin resonance peak in bilayer high-$T_c$ superconductors,"Motivated by a recent experiment on the bilayer
Y$_{1-x}$Ca$_{x}$Ba$_2$Cu$_3$O$_y$ superconductor and based on a bilayer $t-J$
model, we calculate the spin susceptibility at different doping densities in
the even and odd channels in a bilayer system. It is found that the intensity
of the resonance peak in the even channel is much weaker than that in the odd
one, with the resonance position being at a higher frequency. While this
difference decreases as the doping increases, and both the position and
amplitude of the resonance peaks in the two channels are very similar in the
deeply overdoped sample. Moreover, the resonance frequency in the odd channel
is found to be linear with the critical temperature $T_c$, while the resonance
frequency increases as doping decreases in the even channel and tends to
saturate at the underdoped sample. We elaborate the results based on the Fermi
surface topology and the d-wave superconductivity.",0611311v1
2005-07-22,Phenomenology of the Baryon Resonance 70-plet at Large N_c,"We examine the multiplet structure and decay channels of baryon resonances in
the large N_c QCD generalization of the N_c = 3 SU(6) spin-flavor 70. We show
that this ``70'', while a construct of large N_c quark models, actually
consists of five model-independent irreducible spin-flavor multiplets in the
large N_c limit. The preferred decay modes for these resonances fundamentally
depend upon which of the five multiplets to which the resonance belongs. For
example, there exists an SU(3) ``8'' of resonances that is eta-philic and
pi-phobic, and an ``8'' that is the reverse. Moreover, resonances with a strong
SU(3) ``1'' component prefer to decay via a K-bar rather than via a pi.
Remarkably, available data appears to bear out these conclusions.",0507267v1
2008-10-20,A resonance theory for open quantum systems with time-dependent dynamics,"We develop a resonance theory to describe the evolution of open systems with
time-dependent dynamics. Our approach is based on piecewise constant
Hamiltonians: we represent the evolution on each constant bit using a recently
developed dynamical resonance theory, and we piece them together to obtain the
total evolution. The initial state corresponding to one time-interval with
constant Hamiltonian is the final state of the system corresponding to the
interval before. This results in a non-markovian dynamics. We find a
representation of the dynamics in terms of resonance energies and resonance
states associated to the Hamiltonians, valid for all times $t\geq 0$ and for
small (but fixed) interaction strengths. The representation has the form of a
path integral over resonances. We present applications to a spin-fermion
system, where the energy levels of the spin may undergo rather arbitrary
crossings in the course of time. In particular, we find the probability for
transition between ground- and excited state at all times.",0810.3540v1
2008-11-05,Resonant charge and spin transport in a t-stub coupled to a superconductor,"We study transport through a single channel t-stub geometry strongly coupled
to a superconducting reservoir. In contrast to the standard stub geometry which
has both transmission resonances and anti-resonances in the coherent limit, we
find that due to the proximity effect, this geometry shows neither a T=1
resonance (T is the transmission probability for electrons incident on the
t-stub) nor a T=0 anti-resonance as we vary the energy of the incident
electron. Instead, we find that there is only one resonant value at T=1/4,
where charge transport vanishes while the spin transport is perfect.",0811.0660v4
2012-02-28,Superconducting coplanar waveguide resonators for low temperature pulsed electron spin resonance spectroscopy,"We discuss the design and implementation of thin film superconducting
coplanar waveguide micro- resonators for pulsed ESR experiments. The
performance of the resonators with P doped Si epilayer samples is compared to
waveguide resonators under equivalent conditions. The high achievable filling
factor even for small sized samples and the relatively high Q-factor result in
a sensitivity that is superior to that of conventional waveguide resonators, in
particular to spins close to the sample surface. The peak microwave power is on
the order of a few microwatts, which is compatible with measurements at ultra
low temperatures. We also discuss the effect of the nonuniform microwave
magnetic field on the Hahn echo power dependence.",1202.6305v1
2012-04-16,Nonlinear Induction Detection of Electron Spin Resonance,"We present a new approach to the induction detection of electron spin
resonance (ESR) signals exploiting the nonlinear properties of a
superconducting resonator. Our experiments employ a yttrium barium copper oxide
(YBCO) superconducting stripline microwave (MW) resonator integrated with a
microbridge. A strong nonlinear response of the resonator is thermally
activated in the microbridge when exceeding a threshold in the injected MW
power. The responsivity factor characterizing the ESR-induced change in the
system's output signal is about 100 times larger when operating the resonator
near the instability threshold, compared to the value obtained in the linear
regime of operation. Preliminary experimental results, together with a
theoretical model of this phenomenon are presented. Under appropriate
conditions nonlinear induction detection of ESR can potentially improve upon
the current capabilities of conventional linear induction detection ESR.",1204.3588v2
2012-11-15,Spin-2 Resonances in Vector-Boson-Fusion Processes at NLO QCD,"The most likely spin assignments of the recently discovered 126 GeV resonance
are spin 0 or 2. In order to distinguish the two, we construct an effective
Lagrangian model which comprises interactions of a spin-2 electroweak singlet
or triplet state with the SM gauge bosons. Within this model, cross sections
and differential distributions are calculated and implemented within the Monte
Carlo program VBFNLO, which simulates vector-boson-fusion processes at hadron
colliders at NLO QCD accuracy. We study the phenomenology of spin-2 resonances
produced in vector-boson-fusion processes at the LHC. Specifically, we consider
light Higgs-like spin-2 resonances decaying into two photons and show how
angular distributions allow us to distinguish between a Standard Model Higgs
and a spin-2 resonance. We also investigate the characteristics of heavy spin-2
resonances which decay into two weak gauge bosons, leading to a four-lepton
final state.",1211.3658v2
2014-12-02,Broadband Electrically Detected Magnetic Resonance Using Adiabatic Pulses,"We present a broadband microwave setup for electrically detected magnetic
resonance (EDMR) based on microwave antennae with the ability to apply
arbitrarily shaped pulses for the excitation of electron spin resonance (ESR)
and nuclear magnetic resonance (NMR) of spin ensembles. This setup uses
non-resonant stripline structures for on-chip microwave delivery and is
demonstrated to work in the frequency range from 4 MHz to 18 GHz. $\pi$ pulse
times of 50 ns and 70 $\mu$s for ESR and NMR transitions, respectively, are
achieved with as little as 100 mW of microwave or radiofrequency power. The use
of adiabatic pulses fully compensates for the microwave magnetic field
inhomogeneity of the stripline antennae, as demonstrated with the help of BIR4
unitary rotation pulses driving the ESR transition of neutral phosphorus donors
in silicon and the NMR transitions of ionized phosphorus donors as detected by
electron nuclear double resonance (ENDOR).",1412.0842v1
2022-10-25,Microwave-optical double resonance in a erbium-doped whispering-gallery-mode resonator,"We showcase an erbium-doped whispering-gallery-mode resonator with optical
modes that display intrinsic quality factors better than $10^8$ (linewidths
less than 2 MHz), and coupling strengths to collective erbium transitions of up
to 2$\pi\times$1.2 GHz - enough to reach the ensemble strong coupling regime.
Our optical cavity sits inside a microwave resonator, allowing us to probe the
spin transition which is tuned by an external magnetic field. We show a
modified optically detected magnetic resonance measurement that measures
population transfer by a change in coupling strength rather than absorption
coefficient. This modification was enabled by the strong coupling to our modes,
and allows us to optically probe the spin transition detuned by more than the
inhomogeneous linewidth. We contrast this measurement with electron
paramagnetic resonance to experimentally show that our optical modes are
confined in a region of large microwave magnetic field and we explore how such
a geometry could be used for coherent microwave-optical transduction.",2210.13793v1
2006-02-27,Analogue of Cavity QED for Coupling between Spin and Nanomechanical Resonator,"We describe a cavity QED analogue for the coupling system of a spin and a
nanomechanical resonator with a magnetic tip. For the quantized nanomechanical
resonator, a spin-boson model for this coupling system can refer to a
Jaynes-Cummings(JC) or an anti-JC model. These observations predict some
quantum optical phenomena, such as squeezing and ""collapse-revival"" in the
single oscillation mode of the nanomechanical resonator when it is initially
prepared in the quasi-classical state. By modulating the phase of RF magnetic
field one can switch the system between the JC and anti-JC model, which
provides a potential protocol for the detection of the single spin. A damping
mechanism is also analyzed.",0602219v2
2007-05-02,Spin-polarized transport in II-VI magnetic resonant tunneling devices,"We investigate electronic transport through II-VI semiconductor resonant
tunneling structures containing diluted magnetic impurities. Due to the
exchange interaction between the conduction electrons and the impurities, there
arises a giant Zeeman splitting in the presence of a moderately low magnetic
field. As a consequence, when the quantum well is magnetically doped the
current-voltage characteristics shows two peaks corresponding to transport for
each spin channel. This behavior is experimentally observed and can be
reproduced with a simple tunneling model. The model thus allows to analyze
other configurations. First, we further increase the magnetic field, which
leads to a spin polarization of the electronic current injected from the leads,
thus giving rise to a relative change in the current amplitude. We demonstrate
that the spin polarization in the emitter can be determined from such a change.
Furthermore, in the case of a magnetically doped injector our model shows a
large increase in peak amplitude and a shift of the resonance to higher
voltages as the external field increases. We find that this effect arises from
a combination of giant Zeeman splitting, 3-D incident distribution and broad
resonance linewidth.",0705.0237v1
2010-06-01,Strong Coupling of a Spin Ensemble to a Superconducting Resonator,"We report the realization of a quantum circuit in which an ensemble of
electronic spins is coupled to a frequency tunable superconducting resonator.
The spins are Nitrogen-Vacancy centers in a diamond crystal. The achievement of
strong coupling is manifested by the appearance of a vacuum Rabi splitting in
the transmission spectrum of the resonator when its frequency is tuned through
the NV center electron spin resonance.",1006.0251v3
2010-06-18,Force-detected nuclear magnetic resonance: Recent advances and future challenges,"We review recent efforts to detect small numbers of nuclear spins using
magnetic resonance force microscopy. Magnetic resonance force microscopy (MRFM)
is a scanning probe technique that relies on the mechanical measurement of the
weak magnetic force between a microscopic magnet and the magnetic moments in a
sample. Spurred by the recent progress in fabricating ultrasensitive force
detectors, MRFM has rapidly improved its capability over the last decade. Today
it boasts a spin sensitivity that surpasses conventional, inductive nuclear
magnetic resonance detectors by about eight orders of magnitude. In this review
we touch on the origins of this technique and focus on its recent application
to nanoscale nuclear spin ensembles, in particular on the imaging of nanoscale
objects with a three-dimensional (3D) spatial resolution better than 10 nm. We
consider the experimental advances driving this work and highlight the
underlying physical principles and limitations of the method. Finally, we
discuss the challenges that must be met in order to advance the technique
towards single nuclear spin sensitivity -- and perhaps -- to 3D microscopy of
molecules with atomic resolution.",1006.3736v1
2011-02-16,Determination of the Spin of New Resonances in Electroweak Gauge Boson Pair Production at the LHC,"The appearance of spin-1 resonances associated to the electroweak symmetry
breaking (EWSB) sector is expected in many extensions of the Standard Model. We
analyze the CERN Large Hadron Collider potential to probe the spin of possible
new charged and neutral vector resonances through the purely leptonic processes
pp --> Z^\prime --> l^+ l^{\prime -} Emiss_T, and pp --> W^\prime --> l^{\prime
\pm} l^+ l^- Emiss_T, with l, l^\prime = e or \mu. We perform a model
independent analysis and demonstrate that the spin of the new states can be
determined with 99% CL in a large fraction of the parameter space where these
resonances can be observed with 100 fb^{-1}. We show that the best sensitivity
to the spin is obtained by directly studying correlations between the final
state leptons, without the need of reconstructing the events in their
center-of-mass frames.",1102.3429v2
2012-08-11,Spin dependent recombination based magnetic resonance spectroscopy of bismuth donor spins in silicon at low magnetic fields,"Low-field (6-110 mT) magnetic resonance of bismuth (Bi) donors in silicon has
been observed by monitoring the change in photoconductivity induced by spin
dependent recombination. The spectra at various resonance frequencies show
signal intensity distributions drastically different from that observed in
conventional electron paramagnetic resonance, attributed to different
recombination rates for the forty possible combinations of spin states of a
pair of a Bi donor and a paramagnetic recombination center. An excellent
tunability of Bi excitation energy for the future coupling with superconducting
flux qubits at low fields has been demonstrated.",1208.2313v1
2013-01-19,Giant spin-polarized current in a Dirac fermion system at cyclotron resonance,"We report on the observation of the giant spin-polarized photocurrent in
HgTe/HgCdTe quantum well (QW) of critical thickness at which a Dirac spectrum
emerges. Exciting QW of 6.6 nm width by terahertz (THz) radiation and sweeping
magnetic field we detected a resonant photocurrent. Remarkably, the position of
the resonance can be tuned from negative (-0.4 T) to positive (up to 1.2 T)
magnetic fields by means of optical gating. The photocurent data, accompanied
by measurements of radiation transmission as well as Shubnikov-de Haas and
quantum Hall effects, give an evidence that the enhancement of the photocurrent
is caused by cyclotron resonance in a Dirac fermion system. The developed
theory shows that the current is spin polarized and originates from the spin
dependent scattering of charge carriers heated by the radiation.",1301.4572v1
2013-10-07,Multi-resonance orbital model applied to high-frequency quasi-periodic oscillations observed in Sgr A*,"The multi-resonance orbital model of high-frequency quasi-periodic
oscillations (HF QPOs) enables precise determination of the black hole
dimensionless spin a if observed set of oscillations demonstrates three (or
more) commensurable frequencies. The black hole spin is related to the
frequency ratio only, while its mass M is related to the frequency magnitude.
The model is applied to the triple frequency set of HF QPOs observed in Sgr A*
source with frequency ratio 3:2:1. Acceptable versions of the multi-resonance
model are determined by the restrictions on the Sgr A* supermassive black hole
mass. Among the best candidates the version of strong resonances related to the
black hole ""magic"" spin a=0.983 belongs. However, the version demonstrating the
best agreement with the mass restrictions predicts spin a=0.980.",1310.1856v1
2014-08-22,Resonant Spin Tunneling in Randomly Oriented Nanospheres of Mn$_{12}$ Acetate,"We report measurements and theoretical analysis of resonant spin tunneling in
randomly oriented nanospheres of a molecular magnet. Amorphous nanospheres of
Mn$_{12}$ acetate have been fabricated and characterized by chemical, infrared,
TEM, X-ray, and magnetic methods. Magnetic measurements have revealed sharp
tunneling peaks in the field derivative of the magnetization that occur at the
typical resonant field values for Mn$_{12}$ acetate. Theoretical analysis is
provided that explains these observations. We argue that resonant spin
tunneling in a molecular magnet can be established in a powder sample, without
the need for a single crystal and without aligning the easy magnetization axes
of the molecules. This is confirmed by re-analyzing the old data on a powdered
sample of non-oriented micron-size crystals of Mn$_{12}$ acetate. Our findings
can greatly simplify the selection of candidates for quantum spin tunneling
among newly synthesized molecular magnets.",1408.5359v1
2014-09-23,Anisotropic neutron spin resonance in underdoped superconducting NaFe1-xCoxAs,"We use polarized inelastic neutron scattering (INS) to study spin excitations
in superconducting NaFe0.985Co0.015As (C15) with static antiferromagnetic (AF)
order along the a-axis of the orthorhombic structure and NaFe0.935Co0.045As
(C45) without AF order. In previous unpolarized INS work, spin excitations in
C15 were found to have a dispersive sharp resonance near Er1=3.25 meV and a
broad dispersionless mode at Er2=6 meV. Our neutron polarization analysis
reveals that the dispersive resonance in C15 is highly anisotropic and
polarized along the a- and c-axis, while the dispersionless mode is isotropic
similar to that of C45. Since the a-axis polarized spin excitations of the
anisotropic resonance appear below Tc, our data suggests that the itinerant
electrons contributing to the magnetism are also coupled to the
superconductivity.",1409.6416v1
2014-12-30,Optically Detected Magnetic Resonance Imaging,"Optically detected magnetic resonance (ODMR) provides ultrasensitive means to
detect and image a small number of electron and nuclear spins, down to the
single spin level with nanoscale resolution. Despite the significant recent
progress in this field, it has never been combined with the power of pulsed
magnetic resonance imaging (MRI) techniques. Here, we demonstrate for the first
time how these two methodologies can be integrated using short pulsed magnetic
field gradients to spatially-encode the sample. This results in what we denote
as an ""optically detected magnetic resonance imaging"" (ODMRI) technique. It
offers the advantage that the image is acquired in parallel from all parts of
the sample, with well-defined three-dimensional point-spread function, and
without any loss of spectroscopic information. In addition, this approach may
be used in the future for parallel but yet spatially-selective efficient
addressing and manipulation of the spins in the sample. Such capabilities are
of fundamental importance in the field of quantum spin-based devices and
sensors.",1412.8650v1
2015-04-11,Orbital Feshbach Resonance in Alkali-Earth Atoms,"For a mixture of alkali-earth atomic gas in the long-lived excited state
${}^3P_0$ and ground state ${}^1S_0$, in addition to nuclear spin, another
""orbital"" index is introduced to distinguish these two internal states. In this
letter we propose a mechanism to induce Feshbach resonance between two atoms
with different orbital and nuclear spin quantum numbers. Two essential
ingredients are inter-orbital spin-exchanging scattering and orbital dependence
of the Land\'e g-factors. Here the orbital degrees of freedom plays similar
role as electron spin degree of freedom in magnetic Feshbach resonance in
alkali-metal atoms. This resonance is particularly accessible for ${}^{173}$Yb
system. The BCS-BEC crossover in this system requires two fermion pairing order
parameters, and displays significant difference comparing to that in
alkali-metal system.",1504.02864v2
2015-05-11,An electromechanical Ising machine,"Solving intractable mathematical problems in simulators composed of atoms,
ions, photons or electrons has recently emerged as a subject of intense
interest. Here we extend this concept to phonons that are localised in
spectrally pure resonances in an electromechanical system which enables their
interactions to be exquisitely fashioned via electrical means. We harness this
platform to emulate the Ising Hamiltonian whose spin 1/2 particles are
replicated by the phase bistable vibrations from a parametric resonance where
multiple resonances play the role of a spin bath. The coupling between the
mechanical pseudo spins is created by generating thermomechanical two-mode
squeezed states which impart correlations between resonances that can imitate a
ferromagnetic, random or an anti-ferromagnetic state on demand. These results
suggest an electromechanical simulator for the Ising Hamiltonian could be built
with a large number of spins with multiple degrees of coupling, a task that
would overwhelm a conventional computer.",1505.02467v1
2015-07-24,Reaching the quantum limit of sensitivity in electron spin resonance,"We report pulsed electron-spin resonance (ESR) measurements on an ensemble of
Bismuth donors in Silicon cooled at 10mK in a dilution refrigerator. Using a
Josephson parametric microwave amplifier combined with high-quality factor
superconducting micro-resonators cooled at millikelvin temperatures, we improve
the state-of-the-art sensitivity of inductive ESR detection by nearly 4 orders
of magnitude. We demonstrate the detection of 1700 bismuth donor spins in
silicon within a single Hahn echo with unit signal-to-noise (SNR) ratio,
reduced to just 150 spins by averaging a single Carr-Purcell-Meiboom-Gill
sequence. This unprecedented sensitivity reaches the limit set by quantum
fluctuations of the electromagnetic field instead of thermal or technical
noise, which constitutes a novel regime for magnetic resonance.",1507.06831v1
2017-08-30,"Inductive-detection electron-spin resonance spectroscopy with $\mathbf{65}\,$spins$/\sqrt{\text{Hz}}$ sensitivity","We report electron spin resonance spectroscopy measurements performed at
millikelvin temperatures in a custom-built spectrometer comprising a
superconducting micro-resonator at $7$ GHz and a Josephson parametric
amplifier. Owing to the small ${\sim}10^{-12}\lambda^3$ magnetic resonator mode
volume and to the low noise of the parametric amplifier, the spectrometer
sensitivity reaches $260\pm40$ spins$/$echo and $65\pm10$
$\mathrm{spins}/\sqrt{\text{Hz}}$, respectively.",1708.09287v1
2018-06-12,Prospects For A Muon Spin Resonance Facility In The Fermilab MuCool Test Area,"This paper investigates the feasibility of re-purposing the MuCool Test Area
(MTA) beamline and experimental hall to support a Muon Spin Resonance (MuSR)
facility, which would make it the only such facility in the US. This report
reviews the basic muon production concepts studied and operationally
implemented at TRIUMF, PSI, and RAL and their application in the context of the
MTA facility. Two scenarios were determined feasible. One, an initial
minimal-shielding and capital-cost investment stage with a single secondary
muon beamline that utilizes an existing high-intensity beam absorber and,
another, upgraded stage, that implements an optimized production target pile, a
proximate high-intensity absorber, and optimized secondary muon lines. A unique
approach is proposed which chops or strips a macropulse of H- beam into a
micropulse substructure - a muon creation timing scheme - which allows Muon
Spin Resonance experiments in a linac environment. With this timing scheme, and
attention to target design and secondary beam collection, the MTA can host
enabling and competitive Muon Spin Resonance experiments.",1806.04595v1
2018-09-25,Feasibility of imaging using Boltzmann polarization in nuclear Magnetic Resonance Force Microscopy,"We report on Magnetic Resonance Force Microscopy measurements of the
Boltzmann polarization of the nuclear spins in copper by detecting the
frequency shift of a soft cantilever. We use the time-dependent solution of the
Bloch equations to derive a concise equation describing the effect of rf
magnetic fields on both on- and off-resonant spins in high magnetic field
gradients. We then apply this theory to saturation experiments performed on a
100 nm thick layer of copper, where we use the higher modes of the cantilever
as source of the rf field. We demonstrate a detection volume sensitivity of
only (40 nm)$^3$, corresponding to about 1.6$\cdot 10^4$ polarized copper
nuclear spins. We propose an experiment on protons where, with the appropriate
technical improvements, frequency-shift based magnetic resonance imaging with a
resolution better than (10 nm)$^3$ could be possible. Achieving this resolution
would make imaging based on the Boltzmann polarization competitive with the
more traditional stochastic spin-fluctuation based imaging, with the
possibility to work at milliKelvin temperatures.",1809.09351v1
2018-07-24,Magnetic Resonance Imaging of Single Atoms,"Magnetic resonance imaging (MRI) revolutionized diagnostic medicine and
biomedical research by allowing a noninvasive access to spin ensembles. To
enhance MRI resolution to the nanometer scale, new approaches including
scanning probe methods have been used in recent years, which culminated in
detection of individual spins. This allowed three-dimensional (3D)
visualization of organic samples and of sophisticated spin-structures. Here, we
demonstrate for the first time MRI of individual atoms on a surface. The setup,
implemented in a cryogenic scanning tunneling microscope (STM), uses
single-atom electron spin resonance (ESR) to achieve sub-{\AA}ngstr\""om
resolution exceeding the spatial resolution of previous experiments by one to
two orders of magnitude. We find that MRI scans of different atomic species and
probe tips lead to unique signatures in the resonance images. These signatures
reveal the magnetic interactions between the tip and the atom, in particular
magnetic dipolar and exchange interaction.",1807.08944v1
2018-02-15,Tunneling magnetoresistance enhancement by symmetrization in spin-orbit torque magnetic tunnel junction,"Heavy metals with strong spin-orbit coupling (SOC) have been employed to
generate spin current to control the magnetization dynamics by spin-orbit
torque (SOT). Magnetic tunnel junction based on SOT (SOT-MTJ) is a promising
application with efficient writing operation. Unfortunately, SOT-MTJ faces the
low tunneling magnetoresistance (TMR) problem. In this work, we present an ab
initio calculation on the TMR in SOT-MTJ. It is demonstrated that TMR would be
enhanced by SOT-MTJ symmetry structure. The symmetrization induces interfacial
resonant states (IRSs). When IRSs match identical resonances at the opposite
barrier interface, resonant tunneling occurs in SOT-MTJ, which significantly
contributes to the conductance in parallel configuration and improves TMR. We
demonstrate the occurrence of resonant tunneling by transmission spectra,
density of scattering states and differential density of states. We also point
out that the thickness of heavy metal has limited influence on TMR. This work
would benefit the TMR optimization in SOT-MTJ, as well as the SOT spintronics
device.",1802.05787v2
2019-02-27,High-contrast two-quantum optically detected resonances in NV centers in diamond in zero magnetic field,"The methods for controlling spin states of negatively charged
nitrogen-vacancy centers using a combination of microwave (MW) or
radiofrequency (RF) excitation field for electron spin transitions and RF
excitation field for nuclear spin transitions are most effective in strong
magnetic fields where level anti-crossing (LAC) occurs. However, LAC in zero
field can also be used to control spin states, as well as to excite narrow
resonances for metrological application. In this paper we present magnetically
independent resonances arising in the ODMR spectra of NV centers in bulk
diamond under two-frequency (MW+RF) resonant excitation in zero magnetic field,
and discuss their specificity.",1902.10481v3
2020-04-07,Observation of a neutron spin resonance in the bilayered superconductor CsCa2Fe4As4F2,"We report inelastic neutron scattering (INS) investigations on the bilayer
Fe-based superconductor CsCa2Fe4As4F4 above and below its superconducting
transition temperature Tc = 28.9 K to investigate the presence of a neutron
spin resonance. This compound crystallises in a body-centred tetragonal lattice
containing asymmetric double layers of Fe2As2 separated by insulating CaF2
layers and is known to be highly anisotropic. Our INS study clearly reveals the
presence of a neutron spin resonance that exhibits higher intensity at lower
momentum transfer (Q) at 5K compared to 54 K, at an energy of 15 meV. The
energy ER of the observed spin resonance is broadly consistent with the
relationship E_R = 4.9 k_B T_c, but is slightly enhanced compared to the values
observed in other Fe-based superconductors. We discuss the nature of the
electron pairing symmetry by comparing the value of E_R with that deduced from
the total superconducting gap value integrated over the Fermi surface.",2004.03567v1
2020-08-18,Near-Zero-Field Spin-Dependent Recombination Current and Electrically Detected Magnetic Resonance from the Si/SiO$_2$ interface,"Dielectric interfaces critical for metal-oxide-semiconductor (MOS) electronic
devices, such as the Si/SiO$_2$ MOS field effect transistor (MOSFET), possess
trap states that can be visualized with electrically-detected spin resonance
techniques, however the interpretation of such measurements has been hampered
by the lack of a general theory of the phenomena. This article presents such a
theory for two electrical spin-resonance techniques, electrically detected
magnetic resonance (EDMR) and the recently observed near-zero field
magnetoresistance (NZFMR), by generalizing Shockley Read Hall trap-assisted
recombination current calculations via stochastic Liouville equations. Spin
mixing at this dielectric interface occurs via the hyperfine interaction, which
we show can be treated either quantum mechanically or semiclassically, yielding
distinctive differences in the current across the interface. By analyzing the
bias dependence of NZFMR and EDMR, we find that the recombination in a
Si/SiO$_2$ MOSFET is well understood within a semiclassical approach.",2008.08121v1
2016-03-24,Measurement of paramagnetic spin concentration in a solid-state system using double electron-electron resonance,"Diamond has been extensively investigated recently due to a wide range of
potential applications of nitrogen-vacancy (NV) defect centers existing in a
diamond lattice. The applications include magnetometry and quantum information
technologies, and long decoherence time ($T_2$) of NV centers is critical for
those applications. Although it has been known that $T_2$ highly depends on the
concentration of paramagnetic impurities in diamond, precise measurement of the
impurity concentration remains challenging. In the preset work, we show a
method to determine a wide range of the nitrogen concentration ($n$) in diamond
using a wide-band high-frequency electron spin resonance and double
electron-electron resonance spectrometer. Moreover, we investigate $T_2$ of the
nitrogen impurities and show the relationship between $T_2$ and $n$. The method
developed here is applicable for various spin systems in solid and
implementable in nanoscale magnetic resonance spectroscopy with NV centers to
characterize the concentration of the paramagnetic spins within a microscopic
volume.",1603.07404v1
2020-11-30,Deterministic preparation of spin qubits in droplet etched GaAs quantum dots using quasi-resonant excitation,"We present a first comprehensive study on deterministic spin preparation
employing excited state resonances of droplet etched GaAs quantum dots. This
achievement facilitates future investigations of spin qubit based quantum
memories using the GaAs quantum dot material platform. By observation of
excitation spectra for a range of fundamental excitonic transitions the
properties of different quantum dot energy levels, i.e. shells, are revealed.
The innovative use of polarization resolved excitation and detection in
quasi-resonant excitation spectroscopy facilitates determination of $85$ $\%$
maximum spin preparation fidelity - irrespective of the relative orientations
of lab and quantum dot polarization eigenbases. Additionally, the
characteristic non-radiative decay time is investigated as a function of ground
state, excitation resonance and excitation power level, yielding decay times as
low as $29$ ps for s-p-shell exited state transitions. Finally, by time
resolved correlation spectroscopy it is demonstrated that the employed
excitation scheme has a significant impact on the electronic environment of
quantum dot transitions thereby influencing its charge and coherence.",2011.14641v1
2019-10-21,Prospects of forming high-spin polar molecules from ultracold atoms,"We have investigated Feshbach resonances in collisions of high-spin atoms
such as Er and Dy with closed-shell atoms such as Sr and Yb, using
coupled-channel scattering and bound-state calculations. We consider both
low-anisotropy and high-anisotropy limits. In both regimes we find many
resonances with a wide variety of widths. The wider resonances are suitable for
tuning interatomic interactions, while some of the narrower resonances are
highly suitable for magnetoassociation to form high-spin molecules. These
molecules might be transferred to short-range states, where they would have
large magnetic moments and electric dipole moments that can be induced with
very low electric fields. The results offer the opportunity to study mixed
quantum gases where one species is dipolar and the other is not, and open up
important prospects for a new field of ultracold high-spin polar molecules.",1910.09641v4
2020-07-13,Spin-orbit interaction of light in three-dimensional microcavities,"We investigate the spin-orbit coupling of light in three-dimensional
cylindrical and tube-like whispering gallery mode resonators. We show that its
origin is the transverse confinement of light in the resonator walls, even in
the absence of inhomogeneities or anisotropies. The spin-orbit interaction
results in elliptical far-field polarization (spin) states and causes spatial
separation of polarization handedness in the far field. The ellipticity and
spatial separation are enhanced for whispering gallery modes with higher
excitation numbers along the resonator height. We analyze the asymmetry of the
ellipticity and the tilt of the polarization orientation in the far field of
cone-like microcavities. Furthermore, we find a direct relationship between the
tilt of the polarization orientation in the far field and the local inclination
of the resonator wall. Our findings are based on FDTD-simulations and are
supported by three-dimensional diffraction theory.",2007.06721v1
2023-03-31,Characterization and Coherent Control of Spin Qubits with Modulated Electron Beam and Resonator,"The coherent dynamics and control of spin qubits are essential requirements
for quantum technology. A prominent challenge for coherent control of a spin
qubit in a set of qubits is the destructive effect of the applied magnetic
field on the coherent dynamics of neighbouring qubits due to its spatial
extension. We propose a novel scheme to characterize the coherent dynamics of
these quantum systems and to coherently control them using a magnetic field.
Our scheme consists of a resonator that encompasses the desired quantum system
and a modulated electron beam that passes through the resonator in close
proximity to the quantum system of interest. The dynamics of the system is
obtained by solving the Lindblad master equation. To verify the reliability of
our model, we tested the model on a Potassium atom, $^{41}$K and NV$^-$ centre
in Diamond. The results show that by properly controlling the parameters of the
resonator and the electron beam, the coherence and decoherence rates of these
quantum systems can be improved. Our model has the potential to be used for
characterizing different types of spin-based quantum systems, and implementing
quantum logic gates for quantum computation.",2303.17952v1
2023-12-05,Resonant versus non-resonant spin readout of a nitrogen-vacancy center in diamond under cryogenic conditions,"The last decade has seen an explosive growth in the use of color centers for
metrology applications, the paradigm example arguably being the
nitrogen-vacancy (NV) center in diamond. Here, we focus on the regime of
cryogenic temperatures and examine the impact of spin-selective, narrow-band
laser excitation on NV readout. Specifically, we demonstrate a more than
four-fold improvement in sensitivity compared to that possible with
non-resonant (green) illumination, largely due to a boost in readout contrast
and integrated photon count. We also leverage nuclear spin relaxation under
resonant excitation to polarize the 14N host, which we then prove beneficial
for spin magnetometry. These results open opportunities in the application of
NV sensing to the investigation of condensed matter systems, particularly those
exhibiting superconducting, magnetic, or topological phases selectively present
at low temperatures.",2312.02907v1
2009-09-02,Black-hole quasinormal resonances: Wave analysis versus a geometric-optics approximation,"It has long been known that null unstable geodesics are related to the
characteristic modes of black holes-- the so called quasinormal resonances. The
basic idea is to interpret the free oscillations of a black hole in the eikonal
limit in terms of null particles trapped at the unstable circular orbit and
slowly leaking out. The real part of the complex quasinormal resonances is
related to the angular velocity at the unstable null geodesic. The imaginary
part of the resonances is related to the instability timescale (or the inverse
Lyapunov exponent) of the orbit. While this geometric-optics description of the
black-hole quasinormal resonances in terms of perturbed null {\it rays} is very
appealing and intuitive, it is still highly important to verify the validity of
this approach by directly analyzing the Teukolsky wave equation which governs
the dynamics of perturbation {\it waves} in the black-hole spacetime. This is
the main goal of the present paper. We first use the geometric-optics technique
of perturbing a bundle of unstable null rays to calculate the resonances of
near-extremal Kerr black holes in the eikonal approximation. We then directly
solve the Teukolsky wave equation (supplemented by the appropriate physical
boundary conditions) and show that the resultant quasinormal spectrum obtained
directly from the wave analysis is in accord with the spectrum obtained from
the geometric-optics approximation of perturbed null rays.",0909.0314v1
2016-01-15,Resonant Amplification of Turbulence by the Blast Wawes,"We discuss an idea whether spherical blast waves can amplify by a non-local
resonant hydrodynamic mechanism inhomogeneities formed by turbulence or phase
segregation in the interstellar medium. We consider the problem of a
blast-wave-turbulence interaction in the Linear Interaction Approximation.
Mathematically, this is an eigenvalue problem for finding the structure and
amplitude of eigenfunctions describing the response of the shock-wave flow to
forced oscillations by external perturbations in the ambient interstellar
medium. Linear analysis shows that the blast wave can amplify density and
vorticity perturbations for a wide range of length scales with amplification
coefficients of up to 20, with amplification the greater, the larger the
length. There also exist resonant harmonics for which the gain becomes formally
infinite in the linear approximation. Their orbital wavenumbers are within the
range of macro- ($l \sim 1$), meso- ($l \sim 20$) and microscopic ($l > 200$)
scales. Since the resonance width is narrow: typically, $\Delta l <1$,
resonance should select and amplify discrete isolated harmonics. We speculate
as to a possible explanation of an observed regular filamentary structure of
regular-shaped round supernova remnants such as SNR 1572, 1006 or 0509-67.5.
Resonant mesoscales found ($l \approx 18 $) are surprisingly close to the
observed scales ($l \approx 15$) of ripples in the shell's surface of SNR
0509-67.5.",1601.03832v1
2016-09-12,"Multiple resonances of a moving, oscillating surface disturbance on a shear current","We consider waves radiated by a disturbance of oscillating strength moving at
constant velocity along the free surface of a shear flow which, when
undisturbed, has uniform horizontal vorticity of magnitude $S$. When no current
is present the problem is a classical one and much studied, and in deep water a
resonance is known to occur when $\tau=|\boldsymbol{V}|\omega_0/g$ equals the
critical value $1/4$ ($\boldsymbol{V}$: velocity of disturbance, $\omega_0$:
oscillation frequency, $g$: gravitational acceleration). We show that the
presence of the sub-surface shear current can change this picture radically.
Not only does the resonant value of $\tau$ depend strongly on the angle between
$\boldsymbol{V}$ and the current's direction and the ""shear-Froude number""
$\mathrm{Frs}=|\boldsymbol{V}|S/g$; when $\mathrm{Frs}>1/3$, multiple resonant
values --- as many as $4$ --- can occur for some directions of motion. At
sufficiently large values of $\mathrm{Frs}$, the smallest resonance frequency
tends to zero, representing the phenomenon of critical velocity for ship waves.
We provide a detailed analysis of the dispersion relation for the moving,
oscillating disturbance, in both finite and infinite water depth, including for
the latter case an overview of the different far-field waves which exist in
different sectors of wave vector space under different conditions. Owing to the
large number of parameters, a detailed discussion of the structure of
resonances is provided for infinite depth only, where analytical results are
available.",1609.03342v1
2022-04-08,Doubly resonant photoacoustic spectroscopy: ultra-high sensitivity meets ultra-wide dynamic range,"Photoacoustic spectroscopy (PAS) based gas sensors with high sensitivity,
wide dynamic range, low cost, and small footprint are desirable across a broad
range of applications in energy, environment, safety, and public health.
However, most works have focused on either acoustic resonator to enhance
acoustic wave or optical resonator to enhance optical wave. Herein, we develop
a gas sensor based on doubly resonant PAS in which the acoustic and optical
waves are simultaneously enhanced using combined optical and acoustic
resonators in a centimeter-long configuration. Not only the lower detection
limit is enhanced by the double standing waves, but also the upper detection
limit is expanded due to the short resonators. As an example, we developed a
sensor by detecting acetylene (C2H2), achieving a noise equivalent absorption
of 5.7*10-13 cm-1 and a dynamic range of eight orders. Compared to the
state-of-the-art PAS gas sensors, the developed sensor increases the
sensitivity by two orders of magnitude and extends the dynamic range by three
orders of magnitude. Besides, a laser-cavity-molecule locking strategy is
proposed to provide additional flexibility of fast gas detection.",2204.08004v1
2022-05-30,Do surface gravity waves have a frozen turbulence state?,"We study the energy transfer by exact resonances for surface gravity waves in
a finite periodic spatial domain. Based on a kinematic model simulating the
generation of active wave modes in a finite discrete wavenumber space
$\mathcal{S}_R$, we examine the possibility of direct and inverse energy
cascades. More specifically, we set an initially excited region which
iteratively spreads energy to wave modes in $\mathcal{S}_R$ through exact
resonances. At each iteration, we first activate new modes from scale
resonances (which generate modes with new lengths), then consider two bounding
situations for angle resonances (which transfer energy at the same length
scale): the lower bound where no angle resonance is included and the upper
bound where all modes with the same length as any active mode are excited. Such
a strategy is essential to enable the computation for a large domain
$\mathcal{S}_R$ with the maximum wavenumber $R\sim 10^3$. We show that for both
direct and inverse cascades, the energy cascade to the boundaries of
$\mathcal{S}_R$ can be established when the initially excited region is
sufficiently large, otherwise a frozen turbulence state occurs, with a sharp
transition between the two regimes especially for the direct cascade. Through a
study on the structure of resonant quartets, the mechanism associated with the
sharp transition and the role of angular energy transfer in the cascades are
elucidated.",2205.15459v1
2013-06-29,Spin-orbit evolution of Mercury revisited,"While it is accepted that the eccentricity of Mercury (0.206) favours
entrapment into the 3:2 spin-orbit resonance, open is the question how and when
the capture took place. A recent work by Makarov (2012) has demonstrated that
trapping into this resonance is certain if the eccentricity is larger than 0.2,
provided that we use a realistic tidal model, the one which is based on the
Darwin-Kaula expansion of the tidal torque. The physics-based tidal model
changes dramatically the statistics of the possible final spin states. First,
we discover that after only one encounter with the spin-orbit 3:2 resonance
this resonance becomes the most probable end-state. Second, if a capture into
this (or any other) resonance takes place, the capture becomes final, several
crossings of the same state being forbidden by our model. Third, within our
model the trapping of Mercury happens much faster than previously believed: for
most histories, 10 - 20 Myr are sufficient. Fourth, even a weak laminar
friction between the solid mantle and a molten core would most likely result in
a capture in the 2:1 or even higher resonance. So the principal novelty of our
paper is that the 3:2 end-state is more ancient than the same end-state
obtained when the constant time lag model is employed. The swift capture
justifies our treatment of Mercury as a homogeneous, unstratified body whose
liquid core had not yet formed by the time of trapping. We also provide a
critical analysis of the hypothesis by Wieczorek et al. (2012) that the early
Mercury might had been retrograde, whereafter it synchronised its spin and then
accelerated it to the 3:2 resonance. Accurate processing of the available data
on cratering does not support that hypothesis, while the employment of a
realistic rheology invalidates a key element of the hypothesis, an intermediate
pseudosynchronous state needed to spin-up to the 3:2 resonance.",1307.0136v7
1997-01-15,Spin dynamics of the spin-Peierls compound CuGeO_3 under magnetic field,"The magnetic field--driven transition in the spin-Peierls system CuGeO_3
associated with the closing of the spin gap is investigated numerically. The
field dependence of the spin dynamical structure factor (seen by inelastic
neutron scattering) and of the momentum dependent static susceptibility are
calculated. In the dimerized phase (H<H_c), we suggest that the strong field
dependence of the transverse susceptibility could be experimentally seen from
the low temperature spin-echo relaxation rate 1/T_{2G} or the second moment of
the NMR spectrum. Above H_c low energy spin excitations appear at
incommensurate wave vectors where the longitudinal susceptibility chi_{zz}(q)
peaks.",9701107v1
1998-03-31,The spin-Peierls instability in spin 1/2 XY chain in the non adiabatic limit,"The spin-Peierls instability in spin 1/2 XY chain coupled to dispersionless
phonons of frequency $\omega$ has been studied in the nonadiabatic limit. We
have chosen the Lang-Firsov variational wave function for the phonon subsystem
to obtain an effective spin Hamiltonian. The effective spin Hamiltonian is then
solved in the framework of mean-field approximation. We observed a dimerized
phase when g is less than a critical value and an anti-ferromagnetic phase when
it is greater than a critical value . The variation of lattice distortion,
dimerized order parameter and energy gap with spin phonon coupling parameter
has also been investigated here.",9803378v1
2002-11-05,"SU(4) Spin-Orbital Two-Leg Ladder, Square and Triangle Lattices","Based on the generalized valence bond picture, a Schwinger boson mean field
theory is applied to the symmetric SU(4) spin-orbital systems. For a two-leg
SU(4) ladder, the ground state is a spin-orbital liquid with a finite energy
gap, in good agreement with recent numerical calculations. In two-dimensional
square and triangle lattices, the SU(4) Schwinger bosons condense at
(\pi/2,\pi/2) and (\pi/3,\pi/3), respectively. Spin, orbital, and coupled
spin-orbital static susceptibilities become singular at the wave vectors, twice
of which the bose condensation arises at. It is also demonstrated that there
are spin, orbital, and coupled spin-orbital long-range orderings in the ground
state.",0211074v1
2005-04-26,Spin lifetimes and strain-controlled spin precession of drifting electrons in zinc blende type semiconductors,"We study the transport of spin polarized electrons in n-GaAs using spatially
resolved continuous wave Faraday rotation. From the measured steady state
distribution, we determine spin relaxation times under drift conditions and, in
the presence of strain, the induced spin splitting from the observed spin
precession. Controlled variation of strain along [110] allows us to deduce the
deformation potential causing this effect, while strain along [100] has no
effect. The electric field dependence of the spin lifetime is explained
quantitatively in terms of an increase of the electron temperature.",0504668v1
2005-08-31,Quantum Spin Effect and Short-Range Order above the Curie Temperature,"Using quantum Heisenberg model calculations with Green's function technique
generalized for arbitrary spins, we found that for a system of small spins the
quantum spin effects significantly contribute to the magnetic short-range order
and strongly affect physical properties of magnets. The spin dynamics
investigation confirms that these quantum spin effects favor the persistence of
propagating spin-wave excitations above the Curie temperature. Our
investigation suggests a reconsideration of prevailing point of view on finite
temperature magnetism to include quantum effects and the magnetic short-range
order.",0508781v1
2006-10-03,Non-diffusive spin dynamics in a two-dimensional electron gas,"We describe measurements of spin dynamics in the two-dimensional electron gas
in GaAs/GaAlAs quantum wells. Optical techniques, including transient
spin-grating spectroscopy, are used to probe the relaxation rates of spin
polarization waves in the wavevector range from zero to $6\times 10^4$
cm$^{-1}$. We find that the spin polarization lifetime is maximal at nonzero
wavevector, in contrast with expectation based on ordinary spin diffusion, but
in quantitative agreement with recent theories that treat diffusion in the
presence of spin-orbit coupling.",0610054v1
2007-09-26,Spin-polarized Current-induced Instability in Spin-Valve with Antiferromagnetic Layer,"In the framework of phenomenological model we consider dynamics of a
compensated collinear antiferromagnet (AFM) in the presence of spin-polarised
current. The model is based on the assumption that AFM spins are localised and
spin torque is transferred to each magnetic sublattice independently. It is
shown that in AFM spin current i) can be a source of the ""negative friction"";
and ii) modifies spin-wave frequencies. Equilibrium state of AFM can be
destabilized by the current polarized in parallel to AFM vector. Threshold
current at which the loss of stability takes place depends upon the magnetic
anisotropy of AFM.",0709.4172v1
2007-09-26,Two Sides of Spin Concept,"The notion of the spin is shown to have two constituents, as exemplified by
the spin of the electron. The first one is related to the form of the wave
equation and determines the fermion or boson particle type. This implies the
spin taking strictly half-integer or integer number. The second side of spin
manifestation is related to the physical nature of the spin of the electron
(and the corresponding magnetic moment) in the interaction resulting in
nonuniform motion. It is shown that in this manifestation spin is no more fixed
constant.",0709.4191v2
2010-03-09,Laser-catalyzed spin-exchange process in a Bose-Einstein condensate,"We show theoretically that it is possible to optically control collective
spin-exchange processes in spinor Bose condensates through virtual
photoassociation. The interplay between optically induced spin exchange and
spin-dependent collisions provides a flexible tool for the control of atomic
spin dynamics, including enhanced or inhibited quantum spin oscillations, the
optically-induced ferromagnetic-to-antiferromagnetic transition, and coherent
matter-wave spin conversion.",1003.1812v1
2011-02-15,Kondo Spin Screening Cloud in Two-dimensional Electron Gas with Spin-orbit Couplings,"A spin-1/2 Anderson impurity in a semiconductor quantum well with Rashba and
Dresselhaus spin-orbit couplings is studied by using a variational wave
function method. The local magnetic moment is found to be quenched at low
temperatures. The spin-spin correlations of the impurity and the conduction
electron density show anisotropy in both spatial and spin spaces, which
interpolates the Kondo spin screenings of a conventional metal and of a surface
of three-dimensional topological insulators.",1102.2947v1
2013-06-04,Collective Spin-Hall Effect for Electron-Hole Gratings,"We show that an electric field parallel to the wavefronts of an electron-hole
grating in a GaAs quantum well generates, via the electronic spin Hall effect,
a spin grating of the same wave vector and with an amplitude that can exceed 1%
of the amplitude of the initial density grating. We refer to this phenomenon as
""collective spin Hall effect"". A detailed study of the coupled-spin charge
dynamics for quantum wells grown in different directions reveals rich features
in the time evolution of the induced spin density, including the possibility of
generating a helical spin grating.",1306.0889v1
2015-01-13,Spin effects induced by thermal perturbation in a normal metal/magnetic insulator system,"Using one of the methods of quantum nonequilibrium statistical physics we
have investigated the spin transport transverse to the normal
metal/ferromagnetic insulator interface in hybrid nanostructures. An
approximation of the effective parameters, when each of the interacting
subsystems (electron spin, magnon, and phonon) is characterized by its own
effective temperature have been considered. The generalized Bloch equations
which describe the spin-wave current propagation in the dielectric have been
derived. Finally, two sides of the spin transport ""coin"" have been revealed:
the diffusive nature of the magnon motion and magnon relaxation processes,
responsible for the spin pumping and the spin-torque effect.",1501.02983v1
2015-04-27,Helical Spin Order from Topological Dirac and Weyl Semimetals,"We study dynamical mass generation and the resultant helical spin orders in
topological Dirac and Weyl semimetals, including the edge states of quantum
spin Hall insulators, the surface states of weak topological insulators, and
the bulk materials of Weyl semimetals. In particular, the helical spin textures
of Weyl semimetals manifest the spin-momentum locking of Weyl fermions in a
visible manner. The spin-wave fluctuations of the helical order carry electric
charge density; therefore, the spin textures can be electrically controlled in
a simple and predictable manner.",1504.07178v2
2016-10-30,"Kinetic analysis of spin current contribution to spectrum of electromagnetic waves in spin-1/2 plasma, Part I: Dielectric permeability tensor for magnetized plasmas","The dielectric permeability tensor for spin polarized plasmas is derived in
terms of the spin-1/2 quantum kinetic model in six-dimensional phase space.
Expressions for the distribution function and spin distribution function are
derived in linear approximations on the path of dielectric permeability tensor
derivation. The dielectric permeability tensor is derived the spin-polarized
degenerate electron gas. It is also discussed at the finite temperature regime,
where the equilibrium distribution function is presented by the spin-polarized
Fermi-Dirac distribution. Consideration of the spin-polarized equilibrium
states opens possibilities for the kinetic modeling of the thermal spin current
contribution in the plasma dynamics.",1610.09689v1
2016-11-29,Spin-sensitive atom mirror via spin-orbit interaction,"Based on the spin-orbit coupling recently implemented in a neutral cold-atom
gas, we propose a scheme to realize spin-dependent scattering of cold atoms. In
particular we consider a matter wave packet of cold-atom gas impinging upon a
step potential created by the optical light field, inside of which the atoms
are subject to spin-orbit interaction. We show that the proposed system can act
as a spin polarizer or spin-selective atom mirror for the incident atomic beam.
The principle and the operating parameter regime of the system are carefully
discussed.",1611.09617v1
2022-08-23,Acoustic spin current generation in superconductors,"We theoretically study the generation of spin current due to a surface
acoustic wave (SAW) in a superconductor. We model an s-wave superconductor as
the mean-field Hamiltonian and calculate spin current generated via
spin-vorticity coupling based on kinetic theory. The results suggest that the
spin current can be driven in a single superconductor layer, and our estimation
suggests that the detectable magnitude of the spin current can be generated in
aluminum. Our proposal may contribute to the advancement of spin transport in
superconductors from application and fundamental physics aspects.",2208.10744v1
2022-10-17,Topological spin defects of light,"Topological defects are found in a variety of systems, and their existence
are robust under perturbations due to their topological nature. Here we
introduce a new type of topological defects found in electromagnetic waves:
topological spin defects. Such a defect is associated with a point where the
electromagnetic spin density is zero, and generically have a nontrivial
topological spin texture surrounding the defect point. Due to such spin
texture, a topological spin defect possesses a quantized topological charge. We
provide examples where isolated defect point, periodic or quasi-periodic defect
lattices can be created. Such topological spin defect points may find
applications in 3D imaging and nanoparticle manipulation.",2210.08694v1
2023-06-08,Spin entanglement in neutron-proton scattering,"In this Letter, I work out spin entanglement properties of neutron-proton
scattering using the exact S-matrix, generalizing previous works based on S
wave. The dependence of spin entanglement on momentum, scattering angle, and
initial spin configuration is investigated for realistic nuclear forces, while
low-energy properties of spin entanglement are analyzed within the framework of
pionless effective field theory at leading order. New connections are found
between spin entanglement and symmetry enhancement of strong interactions.
These results lead to a more complete understanding of how spin entanglement is
generated via neutron-proton interaction. They also lay the theoretical
foundation for controllable production of entangled nucleon-nucleon pairs in
future experiments.",2306.04918v1
2018-02-02,Spin wave emission by spin-orbit torque antennas,"We study the generation of propagating spin waves in Ta/CoFeB waveguides by
spin-orbit torque antennas and compare them to conventional inductive antennas.
The spin-orbit torque was generated by a transverse microwave current across
the magnetic waveguide. The detected spin wave signals for an in-plane
magnetization across the waveguide (Damon-Eshbach configuration) exhibited the
expected phase rotation and amplitude decay upon propagation when the current
spreading was taken into account. Wavevectors up to about 6 rad/$\mu$m could be
excited by the spin-orbit torque antennas despite the current spreading,
presumably due to the non-uniformity of the microwave current. The relative
magnitude of generated anti-damping spin-Hall and Oersted fields was calculated
within an analytic model and it was found that they contribute approximately
equally to the total effective field generated by the spin-orbit torque
antenna. Due to the ellipticity of the precession in the ultrathin waveguide
and the different orientation of the anti-damping spin-Hall and Oersted fields,
the torque was however still dominated by the Oersted field. The prospects for
obtaining a pure spin-orbit torque response are discussed, as are the energy
efficiency and the scaling properties of spin-orbit torque antennas.",1802.00861v2
2023-11-09,Which black hole is spinning? Probing the origin of black-hole spin with gravitational waves,"Theoretical studies of angular momentum transport suggest that isolated
stellar-mass black holes are born with negligible dimensionless spin magnitudes
$\chi \lesssim 0.01$. However, recent gravitational-wave observations indicate
$\gtrsim 40\%$ of binary black hole systems contain at least one black hole
with a non-negligible spin magnitude. One explanation is that the first-born
black hole spins up the stellar core of what will become the second-born black
hole through tidal interactions. Typically, the second-born black hole is the
``secondary'' (less-massive) black hole, though, it may become the ``primary''
(more-massive) black hole through a process known as mass-ratio reversal. We
investigate this hypothesis by analysing data from the third gravitational-wave
transient catalog (GWTC-3) using a ``single-spin'' framework in which only one
black hole may spin in any given binary. Given this assumption, we show that at
least $28\%$ (90% credibility) of the LIGO--Virgo--KAGRA binaries contain a
primary with significant spin, possibly indicative of mass-ratio reversal. We
find no evidence for binaries that contain a secondary with significant spin.
However, the single-spin framework is moderately disfavoured (natural log Bayes
factor $\ln B = 3.1$) when compared to a model that allows both black holes to
spin. If future studies can firmly establish that most merging binaries contain
two spinning black holes, it may call into question our understanding of
formation mechanisms for binary black holes or the efficiency of angular
momentum transport in black hole progenitors.",2311.05182v3
2010-08-05,Nuclear Feedback in a Single Electron-Charged Quantum Dot under Pulsed Optical Control,"Electron spins in quantum dots under coherent control exhibit a number of
novel feedback processes. Here, we present experimental and theoretical
evidence of a feedback process between nuclear spins and a single electron spin
in a single charged InAs quantum dot, controlled by the coherently modified
probability of exciting a trion state. We present a mathematical model
describing competition between optical nuclear pumping and nuclear
spin-diffusion inside the quantum dot. The model correctly postdicts the
observation of a hysteretic sawtooth pattern in the free-induction-decay of the
single electron spin, hysteresis while scanning a narrowband laser through the
quantum dot's optical resonance frequency, and non-sinusoidal fringes in the
spin echo. Both the coherent electron-spin rotations, implemented with
off-resonant ultrafast laser pulses, and the resonant narrow-band optical
pumping for spin initialization interspersed between ultrafast pulses, play a
role in the observed behavior. This effect allows dynamic tuning of the
electron Larmor frequency to a value determined by the pulse timing,
potentially allowing more complex coherent control operations.",1008.0912v2
2017-08-11,"Integrated silicon qubit platform with single-spin addressability, exchange control and robust single-shot singlet-triplet readout","Silicon quantum dot spin qubits provide a promising platform for large-scale
quantum computation because of their compatibility with conventional CMOS
manufacturing and the long coherence times accessible using $^{28}$Si enriched
material. A scalable error-corrected quantum processor, however, will require
control of many qubits in parallel, while performing error detection across the
constituent qubits. Spin resonance techniques are a convenient path to parallel
two-axis control, while Pauli spin blockade can be used to realize local parity
measurements for error detection. Despite this, silicon qubit implementations
have so far focused on either single-spin resonance control, or control and
measurement via voltage-pulse detuning in the two-spin singlet-triplet basis,
but not both simultaneously. Here, we demonstrate an integrated device platform
incorporating a silicon metal-oxide-semiconductor double quantum dot that is
capable of single-spin addressing and control via electron spin resonance,
combined with high-fidelity spin readout in the singlet-triplet basis.",1708.03445v2
2009-08-26,Long-term evolution of the spin of Mercury I. Effect of the obliquity and core-mantle friction,"The present obliquity of Mercury is very low (less than 0.1 degree), which
led previous studies to always adopt a nearly zero obliquity during the
planet's past evolution. However, the initial orientation of Mercury's rotation
axis is unknown and probably much different than today. As a consequence, we
believe that the obliquity could have been significant when the rotation rate
of the planet first encountered spin-orbit resonances. In order to compute the
capture probabilities in resonance for any evolutionary scenario, we present in
full detail the dynamical equations governing the long term evolution of the
spin, including the obliquity contribution.
  The secular spin evolution of Mercury results from tidal interactions with
the Sun, but also from viscous friction at the core-mantle boundary. Here, this
effect is also regarded with particular attention. Previous studies show that a
liquid core enhances drastically the chances of capture in spin-orbit
resonances. We confirm these results for null obliquity, but we find that the
capture probability generally decreases as the obliquity increases. We finally
show that, when core-mantle friction is combined with obliquity evolution, the
spin can evolve into some unexpected configurations as the synchronous or the
1/2 spin-orbit resonance.",0908.3912v1
2018-02-26,Broadband EPR Spectroscopy in Diverse Field Conditions Using Optically Detected Nitrogen-Vacancy Centers in Diamond,"Paramagnetic magnetic resonance, a powerful technique for characterizing and
identifying chemical targets, is increasingly used for imaging; however, low
spin polarization at room temperature and moderate magnetic fields poses
challenges for detecting small numbers of spins. In this work, we use
fluorescence from nitrogen-vacancy (NV) centers in diamond to detect the
electron paramagnetic resonance (EPR) spectrum of optically inactive target
spins under various conditions of field magnitude and orientation. The protocol
requires neither direct microwave manipulation of the NV spins nor spectral
overlap between NV and target spin resonances, thus enabling broadband
detection. This unexpected non-resonant coupling is attributable to a
two-phonon process that relaxes NV spins proximate to the fluctuating dipole
moment of the target spin, suggesting that the sensitivity is determined by the
dipole-dipole coupling strength. This approach holds promise for sensitive EPR
detection, particularly in settings where control over the diamond-crystal
orientation is difficult. This is notably the case for biological sensing
applications, where nanodiamonds are being pursued for their bright, stable
fluorescence and biocompatibility.",1802.09635v3
2016-12-21,Nuclear magnetic resonance and nuclear spin relaxation in AlAs quantum well probed by ESR,"The study of nuclear magnetic resonance and nuclear spin-lattice relaxation
was conducted in an asymmetrically doped to $n\sim1.8\times10^{11}$ cm$^{-2}$
16 nm AlAs quantum well grown in the $[001]$-direction. Dynamic polarization of
nuclear spins due to the hyperfine interaction resulted in the so-called
Overhauser shift of the two-dimensional conduction electron spin resonance. The
maximum shifts achieved in the experiments are several orders of magnitude
smaller than in GaAs-based heterostructures indicating that hyperfine
interaction is weak. The nuclear spin-lattice relaxation time extracted from
the decay of Overhauser shift over time turned out to depend on the filling
factor of the two-dimensional electron system. This observation indicates that
nuclear spin-lattice relaxation is mostly due to the interaction between
electron and nuclear spins. Overhauser shift diminishes resonantly when the
RF-radiation of certain frequencies was applied to the sample. This effect
served as an indirect, yet powerful method for nuclear magnetic resonance
detection: NMR quadrupole splitting of $^{75}$As nuclei was clearly resolved.
Theoretical calculations performed describe well these experimental findings.",1612.07302v1
2019-09-17,Single spin resonance driven by electric modulation of the g factor anisotropy,"We address the problem of electronic and nuclear spin resonance of an
individual atom on a surface driven by a scanning tunnelling microscope.
Several mechanisms have been proposed so far, some of them based on the
modulation of exchange and crystal field associated to a piezoelectric
displacement of the adatom driven by the RF tip electric field. Here we
consider a new mechanism, where the piezoelectric displacement modulates the g
factor anisotropy, leading both to electronic and nuclear spin flip
transitions. We discuss thoroughly the cases of Ti-H (S = 1/2) and Fe (S = 2)
on MgO, relevant for recent experiments. We model the system using two
approaches. First, an analytical model that includes crystal field, spin orbit
coupling and hyperfine interactions. Second, we carry out density functional
based calculations. We find that the modulation of the anisotropy of the g
tensor due to the piezoelectric displacement of the atom is an additional
mechanism for STM based single spin resonance, that would be effective in S =
1/2 adatoms with large spin orbit coupling. In the case of Ti-H on MgO, we
predict a modulation spin resonance frequency driven by the DC electric field
of the tip.",1909.07942v1
2020-06-22,Spin relaxation benchmarks and individual qubit addressability for holes in quantum dots,"We investigate hole spin relaxation in the single- and multi-hole regime in a
2x2 germanium quantum dot array. We use radiofrequency (rf) charge sensing and
observe Pauli Spin-Blockade (PSB) for every second interdot transition up to
the (1,5)-(0,6) anticrossing, consistent with a standard Fock-Darwin spectrum.
We find spin relaxation times $T_1$ as high as 32 ms for a quantum dot with
single-hole occupation and 1.2 ms for a quantum dot occupied by five-holes,
setting benchmarks for spin relaxation times for hole quantum dots.
Furthermore, we investigate the qubit addressability and sensitivity to
electric fields by measuring the resonance frequency dependence of each qubit
on gate voltages. We are able to tune the resonance frequency over a large
range for both the single and multi-hole qubit. Simultaneously, we find that
the resonance frequencies are only weakly dependent on neighbouring gates, and
in particular the five-hole qubit resonance frequency is more than twenty times
as sensitive to its corresponding plunger gate. The excellent individual qubit
tunability and long spin relaxation times make holes in germanium promising for
addressable and high-fidelity spin qubits in dense two-dimensional quantum dot
arrays for large-scale quantum information.",2006.12563v1
2021-11-21,Excited-state spin-resonance spectroscopy of V$_\text{B}^-$ defect centers in hexagonal boron nitride,"The recently discovered spin-active boron vacancy (V$_\text{B}^-$) defect
center in hexagonal boron nitride (hBN) has high contrast optically-detected
magnetic resonance (ODMR) at room-temperature, with a spin-triplet ground-state
that shows promise as a quantum sensor. Here we report temperature-dependent
ODMR spectroscopy to probe spin within the orbital excited-state. Our
experiments determine the excited-state spin Hamiltonian, including a
room-temperature zero-field splitting of 2.1 GHz and a g-factor similar to that
of the ground-state. We confirm that the resonance is associated with spin
rotation in the excited-state using pulsed ODMR measurements, and we observe
Zeeman-mediated level anti-crossings in both the orbital ground- and
excited-state. Our observation of a single set of excited-state spin-triplet
resonance from 10 to 300 K is consistent with an orbital-singlet, which has
consequences for understanding the symmetry of this defect. Additionally, the
excited-state ODMR has strong temperature dependence of both contrast and
transverse anisotropy splitting, enabling promising avenues for quantum
sensing.",2111.10855v1
2022-10-10,Low-energy M1 states in deformed nuclei: spin-scissors or spin-flip?,"The low-energy $M1$ states in deformed $^{164}$Dy and spherical $^{58}$Ni are
explored in the framework of fully self-consistent Quasiparticle Random-Phase
Approximation (QRPA) with various Skyrme forces. The main attention is paid to
orbital and spin $M1$ excitations. The obtained results are compared with the
prediction of the low-energy {\it spin-scissors} $M1$ resonance suggested
within Wigner Function Moments (WFM) approach. A possible relation of this
resonance to low-energy spin-flip excitations is analyzed. In connection with
recent WFM studies, we consider evolution of the low-energy spin-flip states in
$^{164}$Dy with deformation (from the equilibrium value to the spherical
limit). The effect of tensor forces is briefly discussed. It is shown that two
groups of $1^+$ states observed at 2.4-4 MeV in $^{164}$Dy are rather explained
by fragmentation of the orbital $M1$ strength than by the occurrence of the
collective spin-scissors resonance. In general, our calculations do not confirm
the existence of this resonance.",2210.04701v2
2017-08-06,Comparative analysis of magnetic resonance in the polaron pair recombination and the triplet exciton-polaron quenching models,"We present a comparative theoretical study of magnetic resonance within the
polaron pair recombination (PPR) and the triplet exciton-polaron quenching
(TPQ) models. Both models have been invoked to interpret the photoluminescence
detected magnetic resonance (PLDMR) in $\pi$-conjugated materials. We show that
resonance lineshapes calculated within the two models differ dramatically in
several regards. First, in the PPR model, the lineshape exhibits unusual
behavior upon increasing the microwave power: it evolves from fully positive at
weak power to fully negative at strong power. In contrast, in the TPQ model,
the PLDMR is completely positive, showing a monotonic saturation. Second, the
two models predict different dependencies of the resonance signal on the
photoexcitation power, $P_L$. At low $P_L$, the resonance amplitude $\Delta
I/I$ is $\propto P_L$ in the PPR model, while it is $\propto P_L^2$ crossing
over to $P_L^3$ in the TPQ model. On the physical level, the differences stem
from different underlying spin dynamics. Most prominently, a negative resonance
within the PPR model has its origin in the microwave-induced spin-Dicke effect,
leading to the resonant quenching of photoluminescence. The spin-Dicke effect
results from the spin-selective recombination, resulting in a highly correlated
precession of the on-resonance pair-partners under the strong microwave power.
This effect is not relevant to TPQ, where the majority of triplets are
off-resonance due to the strong zero-field splitting. The analytical evaluation
of lineshapes for the two models is enabled by expressing these shapes via the
eigenvalues of a complex Hamiltonian. This bypasses the necessity of solving
the much larger complex system of stochastic Liouville equations. Our findings
pave the way towards a reliable discrimination between the two mechanisms via
cw PLDMR.",1708.01917v1
2018-01-11,Analyticity of Resonances and Eigenvalues and Spectral Properties of the massless Spin-Boson Model,"We extend the method of multiscale analysis for resonances introduced in [5]
in order to infer analytic properties of resonances and eigenvalues (and their
eigenprojections) as well as estimates for the localization of the spectrum of
dilated Hamiltonians and norm-bounds for the corresponding resolvent operators,
in neighborhoods of resonances and eigenvalues. We apply our method to the
massless Spin-Boson model assuming a slight infrared regularization. We prove
that the resonance and the ground-state eigenvalue (and their eigenprojections)
are analytic with respect to the dilation parameter and the coupling constant.
Moreover, we prove that the spectrum of the dilated Spin-Boson Hamiltonian in
the neighborhood of the resonance and the ground-state eigenvalue is localized
in two cones in the complex plane with vertices at the location of the
resonance and the ground-state eigenvalue, respectively. Additionally, we
provide norm-estimates for the resolvent of the dilated Spin-Boson Hamiltonian
near the resonance and the ground-state eigenvalue. The topic of analyticity of
eigenvalues and resonances has let to several studies and advances in the past.
However, to the best of our knowledge, this is the first time that it is
addressed from the perspective of multiscale analysis. Once the multiscale
analysis is set up our method gives easy access to analyticity: Essentially, it
amounts to proving it for isolated eigenvalues only and use that uniform limits
of analytic functions are analytic. The type of spectral and resolvent
estimates that we prove are needed to control the time evolution including the
scattering regime. The latter will be demonstrated in a forthcoming
publication. The introduced multiscale method to study spectral and resolvent
estimates follows its own inductive scheme and is independent (and different)
from the method we apply to construct resonances.",1801.04021v2
1998-01-07,Resonant Raman scattering by collective modes of the one-dimensional electron gas,"We show that the low-energy peak in the polarized resonant Raman spectra of
quantum wires, which is commonly associated with ``single particle
excitations'', can be interpreted as signature of intra-band collective spin
excitations. A broad maximum in the resonant depolarized spectra is predicted
to exist above the frequency of the spin density excitation, due to
simultaneous but independent propagation of spin- and charge-density modes.",9801058v1
2001-08-04,Magnetic Field Pinning of a Dynamic Electron-Spin-Resonance Line in a GaAs/AlGaAs Heterostructure,"Electrically detected electron spin resonance (ESR) is used to study the
hyperfine interaction of the two-dimensional electrons and the nuclei of the
host lattice in a GaAs/AlGaAs heterostructure. Under the microwave and radio-
frequency double excitations, we have observed that the ESR line can be pinned
in a very narrow range of magnetic field - in the vicinity of the nuclear
magnetic resonance (NMR) of the nuclei of the GaAs crystal. Our observations
suggest that this pinning effect is the result of a competition process between
the ESR induced dynamic nuclear polarization and the NMR induced
depolarization.",0108080v1
2002-09-11,Magnetic Anisotropy in La_0.8Sr_0.2MnO_3: Electron Spin Resonance,"We report on Ferromagnetic-Resonance experiments in a single crystal of
La_0.8Sr_0.2MnO_3 in the temperature range from 4 to 300 K. The observed
anisotropy of the resonance line changes on crossing the transition from the
orthorhombic O-phase to the rhombohedral R-phase at T~100 K and indicates a
reorientation of the spins at about 130 K.",0209257v1
2004-11-12,Kondo resonance for orbitally degenerate systems,"Formation of the Kondo state in general two-band Anderson model has been
investigated within the numerical renormalization group (NRG) calculations. The
Abrikosov-Suhl resonance is essentially asymmetric for the model with one
electron per impurity (quarter filling case) in contrast with the one-band
case. An external magnetic (pseudo-magnetic) field breaking spin (orbital)
degeneracy leads to asymmetric splitting and essential broadening of the
many-body resonance. Unlike the standard Anderson model, the ``spin up'' Kondo
peak is pinned against the Fermi level, but not suppressed by magnetic field.",0411323v1
2005-01-26,High-field optically detected nuclear magnetic resonance in GaAs,"A method for high-field optically detected nuclear magnetic resonance (ODNMR)
is developed sensitive to 10**8 nuclei. Nuclear spin transitions are induced
using a radio frequency coil and detected through Faraday rotation
spectroscopy. Unlike conventional ODNMR, which is limited to low fields and
relies on the measurement of time-averaged luminescence polarization, this
technique monitors nuclear polarization through time-resolved measurements of
electron spin dynamics. Measurements in a (110) GaAs quantum well reveal Ga-69,
Ga-71, and As-75 resonances and their quadrupolar splittings while resolving
changes in nuclear polarization of 0.02%.",0501652v1
2006-02-04,Spin-transfer-driven ferromagnetic resonance of individual nanomagnets,"We demonstrate a technique that enables ferromagnetic resonance (FMR)
measurements of the normal modes for magnetic excitations in individual
nanoscale ferromagnets, smaller in volume by a factor of 1000 than can be
probed by other methods. The measured peak shapes indicate two regimes of
response: simple FMR and phase locking. Studies of the resonance frequencies,
amplitudes, and linewidths as a function of microwave power, DC current, and
magnetic field provide detailed new information about the exchange, damping,
and spin-transfer torques that govern the dynamics in magnetic nanostructures.",0602105v1
1995-08-18,Quark Model Explanation of the $N^*\to Nη$ Branching Ratios,"The constituent quark model can explain the strong selectivity of the $N\eta$
decay branching ratios of the nucleon resonances if the fine structure
interaction between the constituent quarks is described in terms of Goldstone
boson exchange. This chiral quark model predicts that the resonances $N(1535)$,
$N(1710)$, $\Lambda(1670)$, $\Sigma(1750)$, which have mixed flavor and spin
symmetry $[21]_{FS} [21]_F [21]_S$ wavefunctions in lowest order, should have
large $N\eta$ branching ratios, while $N\eta$ decay of the other resonances
that have different flavor-spin symmetry should be strongly suppressed in
agreement with the experimental branching ratios.",9508327v1
1998-01-01,Perturbative Duality in the Resonance Spin Structure Functions,"We investigate the relations between the spin structure functions in the
scaling and resonance regions. We examine the possible duality between the two,
and draw inferences for the behavior of the asymmetry A_1 at large x. Finally,
we point out the importance of additional polarized structure function data in
the resonance region in terms of testing the hysteresis of perturbative
physics.",9801205v1
2005-12-27,The Nucleon and Roper Resonance in a Chiral Quark Diquark Model,"A description of the nucleon and Roper resonance in a quark-diquark approach
is presented. We show that two states with the quantum number of the nucleon
can appear in the ground state of the spatial configuration, when there are two
types of diquarks: scalar-isoscalar and axial-vector-isovector diquarks. The
mass difference between the two states is generated by the mass difference
between the two diquarks, which is due to the spin-spin interaction between the
two quarks in the diquarks. The two states are then identified with the nucleon
and Roper resonance.",0512336v1
2001-03-03,Control of Non-Resonant Effects in a Nuclear Spin Quantum Computer with a Large Number of Qubits,"We discuss how to simulate simple quantum logic operations with a large
number of qubits. These simulations are needed for experimental testing of
scalable solid-state quantum computers. Quantum logic for remote qubits is
simulated in a spin chain. Analytical estimates are presented for possible
correlated errors caused by non-resonant transitions. A range of parameters is
given in which non-resonant effects can be minimized.",0103007v1
2007-07-04,Hyperfine-mediated gate-driven electron spin resonance,"An all-electrical spin resonance effect in a GaAs few-electron double quantum
dot is investigated experimentally and theoretically. The magnetic field
dependence and absence of associated Rabi oscillations are consistent with a
novel hyperfine mechanism. The resonant frequency is sensitive to the
instantaneous hyperfine effective field, and the effect can be used to detect
and create sizable nuclear polarizations. A device incorporating a micromagnet
exhibits a magnetic field difference between dots, allowing electrons in either
dot to be addressed selectively.",0707.0557v2
2007-07-30,Comments on ``Spin Connection Resonance in Gravitational General Relativity'',"We comment on a recent article of M.W.Evans, Acta Physica Polonica B38 (2007)
2211. We point out that the equations underlying Evans' theory are highly
problematic. Moreover, we demonstrate that the so-called ``spin connection
resonance'', predicted by Evans, cannot be derived from the equation he used.
We provide an exact solution of Evans' corresponding equation and show that is
has definitely no resonance solutions.",0707.4433v2
2008-08-23,Spin-isospin resonances: A self-consistent covariant description,"For the first time a fully self-consistent charge-exchange relativistic RPA
based on the relativistic Hartree-Fock (RHF) approach is established. The
self-consistency is verified by the so-called isobaric analog state (IAS)
check. The excitation properties and the non-energy weighted sum rules of two
important charge-exchange excitation modes, the Gamow-Teller resonance (GTR)
and the spin-dipole resonance (SDR), are well reproduced in the doubly magic
nuclei $^{48}$Ca, $^{90}$Zr and $^{208}$Pb without readjustment of the
particle-hole residual interaction. The dominant contribution of the exchange
diagrams is demonstrated.",0808.3159v1
2009-07-10,Measurement of Conduction Electron Polarization Via the Pairing Resonance,"We show that the pairing resonance in the Pauli-limited normal state of
ultra-thin superconducting Al films provides a spin-resolved probe of
conduction electron polarization in thin magnetic films. A
superconductor-insulator-ferromagnet tunneling junction is used to measure the
density of states in supercritical parallel magnetic fields that are well
beyond the Clogston-Chandresekhar limit, thus greatly extending the field range
of the tunneling density of states technique. The applicability and limitations
of using the pairing resonance as a spin probe are discussed.",0907.1800v1
2009-07-12,Electrically detected magnetic resonance using radio-frequency reflectometry,"The authors demonstrate readout of electrically detected magnetic resonance
at radio frequencies by means of an LCR tank circuit. Applied to a silicon
field-effect transistor at milli-kelvin temperatures, this method shows a
25-fold increased signal-to-noise ratio of the conduction band electron spin
resonance and a higher operational bandwidth of > 300 kHz compared to the kHz
bandwidth of conventional readout techniques. This increase in temporal
resolution provides a method for future direct observations of spin dynamics in
the electrical device characteristics.",0907.2022v1
2009-08-30,Extraction of an Entanglement by Repetition of the Resonant Transmission of an Ancilla Qubit,"A scheme for the extraction of entanglement in two noninteracting qubits
(spins) is proposed. The idea is to make use of resonant transmission of
ancilla qubit through the two fixed qubits, controlled by the entanglement in
the scatterers. Repetition of the resonant transmission extracts the singlet
state in the target qubits from their arbitrary given state. Neither the
preparation nor the post-selection of the ancilla spin is required, in contrast
to the previously proposed schemes.",0908.4377v2
2010-11-23,Electric-field Manipulation of the Lande' g Tensor of Holes in In0.5Ga0.5As/GaAs Self-assembled Quantum Dots,"The effect of an electric field on spin precession in In0.5Ga0.5As/GaAs
self-assembled quantum dots is calculated using multiband real-space
envelope-function theory. The dependence of the Lande' g tensor on electric
fields should permit high-frequency g tensor modulation resonance, as well as
direct, nonresonant electric-field control of the hole spin. Subharmonic
resonances have also been found in g tensor modulation resonance of the holes,
due to the strong quadratic dependence of components of the hole g tensor on
the electric field.",1011.5014v1
2011-03-25,Temperature dependence of spin resonance in cobalt substituted NiZnCu ferrites,"Cobalt substitutions were investigated in Ni0.4Zn0.4Cu0.2Fe2O4 ferrites,
initial complex permeability was then measured from 1 MHz to 1 GHz. It appears
that cobalt substitution led to a decrease in the permeability and an increase
in the \mus\timesfr factor. As well, it gave to the permeability spectrum a
sharp resonance character. We also observed a spin reorientation occurring at a
temperature depending on the cobalt content. Study of the complex permeability
versus temperature highlighted that the most resonant character was obtained at
this temperature. This shows that cobalt contribution to second order
magnetocrystalline anisotropy plays a leading role at this temperature.",1103.5024v1
2011-08-09,Magnetic resonance from the interplay of frustration and superconductivity,"Motivated by the iron-based superconductors, we develop a self-consistent
electronic theory for the itinerant spin excitations in the regime of
coexistence of the antiferromagnetic stripe order with wavevector ${\bf Q}_{1}
= (\pi,0)$ and $s^{+-}$ superconductivity. The onset of superconductivity leads
to the appearance of a {\em magnetic} resonance near the wavevector ${\bf
Q}_{2} = (0,\pi)$ where magnetic order is absent. This resonance is isotropic
in spin space, unlike the excitations near ${\bf Q}_{1}$ where the magnetic
Goldstone mode resides. We discuss several features which can be observed
experimentally.",1108.2046v1
2011-08-16,Nanomechanical detection of nuclear magnetic resonance using a silicon nanowire oscillator,"We report the use of a silicon nanowire mechanical oscillator as a
low-temperature nuclear magnetic resonance force sensor to detect the
statistical polarization of 1H spins in polystyrene. Under operating
conditions, the nanowire experienced negligible surface-induced dissipation and
exhibited a nearly thermally-limited force noise of 1.9 aN^2/Hz in the
measurement quadrature. In order to couple the 1H spins to the nanowire
oscillator, we have developed a new magnetic resonance force detection protocol
which utilizes a nanoscale current-carrying wire to produce large
time-dependent magnetic field gradients as well as the rf magnetic field.",1108.3263v1
2011-11-22,Lock-in detection for pulsed electrically detected magnetic resonance,"We show that in pulsed electrically detected magnetic resonance (pEDMR)
signal modulation in combination with a lock-in detection scheme can reduce the
low-frequency noise level by one order of magnitude and in addition removes the
microwave-induced non-resonant background. This is exemplarily demonstrated for
spin-echo measurements in phosphorus-doped Silicon. The modulation of the
signal is achieved by cycling the phase of the projection pulse used in pEDMR
for the read-out of the spin state.",1111.5149v1
2012-10-18,Few-Qubit Magnetic Resonance Quantum Information Processors: Simulating Chemistry and Physics,"We review recent progress made in quantum information processing (QIP) which
can be applied in the simulation of quantum systems and chemical phenomena. The
review is focused on quantum algorithms which are useful for quantum simulation
of chemistry and advances in nuclear magnetic resonance (NMR) and electron spin
resonance (ESR) QIP. Discussions also include a number of recent experiments
demonstrating the current capabilities of the NMR QIP for quantum simulation
and prospects for spin-based implementations of QIP.",1210.4994v1
2014-11-12,Neutrino-pair bremsstrahlung from nucleon-$α$ versus nucleon-nucleon scattering,"We study the impact of the nucleon-$\alpha$ P-wave resonances on
neutrino-pair bremsstrahlung. Because of the non-central spin-orbit
interaction, these resonances lead to an enhanced contribution to the nucleon
spin structure factor for temperatures $T \lesssim 4$ MeV. If the
$\alpha$-particle fraction is significant and the temperature is in this range,
this contribution is competitive with neutron-neutron bremsstrahlung. This may
be relevant for neutrino production in core-collapse supernovae or other dense
astrophysical environments. Similar enhancements are expected for resonant
non-central nucleon-nucleus interactions.",1411.3266v1
2014-12-22,Accelerated nanoscale magnetic resonance imaging through phase multiplexing,"We report a method for accelerated nanoscale nuclear magnetic resonance
imaging by detecting several signals in parallel. Our technique relies on phase
multiplexing, where the signals from different nuclear spin ensembles are
encoded in the phase of an ultrasensitive magnetic detector. We demonstrate
this technique by simultaneously acquiring statistically polarized spin signals
from two different nuclear species (1H, 19F) and from up to six spatial
locations in a nanowire test sample using a magnetic resonance force
microscope. We obtain one-dimensional imaging resolution better than 5 nm, and
subnanometer positional accuracy.",1412.6914v2
2015-05-01,Ising incommensurate spin resonance of CeCoIn$_{5}$: a dynamical precursor of the Q-phase,"It is shown by detailed inelastic neutron scattering experiments that the
gapped collective magnetic excitation of the unconventional superconductor
CeCoIn$_{5}$, the spin resonance mode, is incommensurate and that the
corresponding fluctuations are of Ising nature. The incommensurate peak
position of these fluctuations corresponds to the propagation vector of the
adjacent field induced static magnetic ordered phase, the so-called Q-phase.
Furthermore, the direction of the magnetic moment fluctuations is also the
direction of the ordered magnetic moments of the Q-phase. Hence the resonance
mode and the Q-phase share the same symmetry and this strongly supports a
scenario where the static order is realized by a condensation of the magnetic
excitation.",1505.00206v1
2015-06-19,Coherent manipulation of a Majorana qubit by a mechanical resonator,"We propose a hybrid system composed of a Majorana qubit and a nanomechanical
resonator, implemented by a spin-orbit-coupled superconducting nanowire, using
a set of static and oscillating ferromagnetic gates. The ferromagnetic gates
induce Majorana bound states in the nanowire, which hybridize and constitute a
Majorana qubit. Due to the oscillation of one of these gates, the Majorana
qubit can be coherently rotated. By tuning the gate voltage to modulate the
local spin-orbit coupling, it is possible to reach the resonance of the
qubit-oscillator system for relatively strong couplings.",1506.05879v2
2018-10-05,Spin gap in a quasi-1D S=1/2 antiferromagnet K2CuSO4Cl2,"Electron spin resonance experiments in the quasi-1D S=1/2 antiferromagnet
K$_2$CuSO$_4$Cl$_2$ reveal opening of a gap in absence of magnetic ordering, as
well as an anisotropic shift of the resonance magnetic field. These features of
magnetic excitation spectrum are explained by a crossover between a gapped
spinon-type doublet ESR formed in a 1D antiferromagnet with uniform
Dzyaloshinskii-Moriya interaction and a Larmor-type resonance of a quasi-1D
Heisenberg system",1810.02675v2
2016-12-13,Two-body relaxation of spin-polarized fermions in reduced dimensionalities near a p-wave Feshbach resonance,"We study inelastic two-body relaxation in a spin-polarized ultracold Fermi
gas in the presence of a p-wave Feshbach resonance. It is shown that in reduced
dimensionalities, especially in the quasi-one-dimensional case, the enhancement
of the inelastic rate constant on approach to the resonance is strongly
suppressed compared to three dimensions. This may open promising paths for
obtaining novel many-body states.",1612.04107v3
2017-01-15,Side resonances and metastable excited state of NV- center in diamond,"We discuss the side resonances of optically detected magnetic resonance in
diamond crystal and propose the new approach to the calculation of hyperfine
interaction in composed system, consisted of negatively charged
nitrogen-vacancy NV- center and nearby 13C nuclear spin. Energy levels and spin
states are obtained by new method. The base of this method is the using of
complete set of commuting operators. In zero magnetic field, predicted the
existence of metastable excited state.",1701.04097v1
2023-04-05,Zero field magnetic resonance spectroscopy based on Nitrogen-vacancy centers,"We propose a scheme to have zero field magnetic resonance spectroscopy based
on a nitrogen-vacancy center and investigate the new applications in which
magnetic bias field might disturb the system under investigation. Continual
driving with circularly polarized microwave fields is used to selectively
address one spin state. The proposed method is applied for single molecule
spectroscopy, such as nuclear quadrupole resonance spectroscopy of a $^{11}$B
nuclear spin and the detection of the distance of two hydrogen nuclei in a
water molecule. Our work extends applications of NV centers as a nanoscale
molecule spectroscopy in the zero field regime.",2304.02179v1
2023-12-01,Optical chiral properties in a large resonant hybrid photonic cluster,"Optical chiral properties of a resonant hybrid photonic crystal (RHPC) are
computed taking into account spin-orbit effect due to light-hole excitons
perfectly confined in 2D quantum wells. The trends of the optical activity,
expressed as a ratio between the absorption intensities of the z and xy
light-hole polaritons, are obtained by computing the optical response in a
rather large N-cluster of elementary cells (N= 34) and for exciton energy, in
resonance with a stationery inflection point (SIP). High values of spin-orbit
interaction (0.7 eV A) produce strong distortions of the optical activity polar
curves that, differently, becomes rather isotropic if the experimental value
(0.14 eV A) is used.",2312.00669v2
2023-11-20,Evolution of internal gravity waves in meso-scale eddies,"We investigate the effect of wave-eddy interaction and dissipation of
internal gravity waves propagating in a coherent meso-scale eddy simulated
using a novel numerical model called the Internal Wave Energy Model based on
the six-dimensional radiative transfer equation. We use an idealized mean flow
structure and stratification, motivated by observations of a coherent eddy in
the Canary Current System. In a spin-down simulation using the Garret-Munk
model spectrum as initial conditions, we find that wave energy decreases at the
eddy rim. Lateral shear leads to wave energy gain due to a developing
horizontal anisotropy outisde the eddy and at the rim, while vertical shear
leads to wave energy loss which is enhanced at the eddy rim. Wave energy loss
by wave dissipation due to vertical shear dominates over horizontal shear. Our
results show similar behaviour of the internal gravity wave in a cyclonic as
well as an anticyclonic eddy. Wave dissipation by vertical wave refraction
occurs predominantly at the eddy rim near the surface, where related vertical
diffusivities range from $\kappa \approx \mathcal{O}(10^{-7})$ to
$\mathcal{O}(10^{-5}) \, \rm m^2s^{-1}$.",2311.11916v1
2006-06-28,Influence of Random Bulk Inhomogeneities on Quasi-Optical Cavity Resonator Spectrum,"We suggest the statistical spectral theory of oscillations in quasi-optical
cavity resonator filled with random inhomogeneities. It is shown that
inhomogeneities in the resonator result in intermode scattering leading to the
shift and broadening of spectral lines. The shift and broadening of each line
essentially depends on frequency distance to adjacent spectral lines. With
increasing the distance the influence of inhomogeneities sharply reduces. The
solitary spectral lines which have the distance to the nearest lines quite
large is slightly changed due to small inhomogeneities. Owing to such selective
influence of inhomogeneities on the spectral lines the effective spectrum
rarefaction appears. Both the shift and broadening of spectral lines as well as
spectrum rarefaction in quasi-optical cavity millimeter wave resonator were
detected experimentally. We found out that inhomogeneities result in
stochastization of the resonator spectrum in that mixed state appears, i.e. the
spectrum acquires both regular and random parts. The active self-oscillator
system based on the inhomogeneous quasi-optical cavity millimeter wave
resonator with Gunn diode was studied as well. The inhomogeneous quasi-optical
cavity millimeter wave resonator (passive and active) can serve as a model of
semiconductor quantum billiard. Based on our results we suggest using such
billiards with spectrum rarefied by random inhomogeneities as an active system
of semiconductor laser.",0606740v1
2014-06-11,Tunable coupled-mode dispersion compensation and its application to on-chip resonant four-wave mixing,"We propose and demonstrate localized mode coupling as a viable dispersion
engineering technique for phase-matched resonant four-wave mixing (FWM). We
demonstrate a dual-cavity resonant structure that employs coupling-induced
frequency splitting at one of three resonances to compensate for cavity
dispersion, enabling phase-matching. Coupling strength is controlled by thermal
tuning of one cavity enabling active control of the resonant
frequency-matching. In a fabricated silicon microresonator, we show an 8 dB
enhancement of seeded FWM efficiency over the non-compensated state. The
measured four-wave mixing has a peak wavelength conversion efficiency of -37.9
dB across a free spectral range (FSR) of 3.334 THz ($\sim$27 nm). Enabled by
strong counteraction of dispersion, this FSR is, to our knowledge, the largest
in silicon to demonstrate FWM to date. This form of mode-coupling-based, active
dispersion compensation can be beneficial for many FWM-based devices including
wavelength converters, parametric amplifiers, and widely detuned correlated
photon-pair sources. Apart from compensating intrinsic dispersion, the proposed
mechanism can alternatively be utilized in an otherwise dispersionless
resonator to counteract the detuning effect of self- and cross-phase modulation
on the pump resonance during FWM, thereby addressing a fundamental issue in the
performance of light sources such as broadband optical frequency combs.",1406.2750v2
2021-01-25,Kerr-Nonlinearity-Induced Mode-Splitting in Optical Microresonators,"The Kerr effect in optical microresonators plays an important role for
integrated photonic devices and enables third harmonic generation, four-wave
mixing, and the generation of microresonator-based frequency combs. Here we
experimentally demonstrate that the Kerr nonlinearity can split ultra-high-Q
microresonator resonances for two continuous-wave lasers. The resonance
splitting is induced by self- and cross-phase modulation and
counter-intuitively enables two lasers at different wavelengths to be
simultaneously resonant in the same microresonator mode. We develop a
pump-probe spectroscopy scheme that allows us to measure power dependent
resonance splittings of up to 35 cavity linewidths (corresponding to 52 MHz) at
10 mW of pump power. The required power to split the resonance by one cavity
linewidth is only 286${\mu}$W. In addition, we demonstrate threefold resonance
splitting when taking into account four-wave mixing and two counterpropagating
probe lasers. These Kerr splittings are of interest for applications that
require two resonances at optically controlled offsets, eg. for opto-mechanical
coupling to phonon modes, optical memories, and precisely adjustable spectral
filters.",2101.10170v1
2023-09-27,Mean-Motion Resonances With Interfering Density Waves,"In this work, we study the dynamics of two less massive objects moving around
a central massive object, which are all embedded within a thin accretion disc.
In addition to the gravitational interaction between these objects, the
disc-object interaction is also crucial for describing the long-term dynamics
of the multi-body system, especially in the regime of mean-motion resonances.
We point out that near the resonance the density waves generated by the two
moving objects generally coherently interfere with each other, giving rise to
extra angular momentum fluxes. The resulting backreaction on the objects is
derived within the thin-disc scenario, which explicitly depends on the resonant
angle and sensitively depends on the smoothing scheme used in the
two-dimensional theory. We have performed hydrodynamical simulations with
planets embedded within a thin accretion disc and have found qualitatively
agreement on the signatures of interfering density waves by measuring the
torques on the embedded objects. By including in interference torque and the
migration torques in the evolution of a pair of planets, we show that the
chance of resonance trapping depends on the sign of the interference torque.
For negative torques the pairs are more likely located at off-resonance
regimes. The negative torques may also explain the $1\%-2\%$ offset (for the
period ratios) from the exact resonance values as observed in {\it Kepler}
multi-planet systems.",2309.15694v2
2024-03-15,Exact time-evolving scattering states in open quantum-dot systems with an interaction: Discovery of time-evolving resonant states,"We study exact time-evolving many-electron states of an open double
quantum-dot system with an interdot Coulomb interaction. A systematic
construction of the time-evolving states for arbitrary initial conditions is
proposed. For any initial states of one- and two-electron plane waves on the
electrical leads, we obtain exact solutions of the time-evolving scattering
states, which converge to known stationary scattering eigenstates in the
long-time limit. For any initial states of localized electrons on the quantum
dots, we find exact time-evolving states of a new type, which we refer to as
time-evolving resonant states. In contrast to stationary resonant states, whose
wave functions spatially diverge and not normalizable, the time-evolving
resonant states are normalizable since their wave functions are restricted to a
finite space interval due to causality. The exact time-evolving resonant states
enable us to calculate the time-dependence of the survival probability of
electrons on the quantum dots for the system with the linearized dispersions.
It decays exponentially in time on one side of an exponential point of
resonance energies while, on the other side, it oscillates during the decay as
a result of the interference of the two resonance energies.",2403.10251v1
2008-05-22,High-statistics measurement of neutral-pion pair production in two-photon collisions,"We present a high-statistics measurement of differential cross sections and
the total cross section for the process gamma gamma -> pi^0 pi^0 in the
kinematic range 0.6 GeV <= W <= 4.0 GeV and |cos theta*| <= 0.8, where W and
theta* are the energy and pion scattering angle, respectively, in the gamma
gamma center-of-mass system. Differential cross sections are fitted to obtain
information on S, D_0, D_2, G_0 and G_2 waves. The G waves are important above
W ~= 1.6 GeV. General behavior of partial waves is studied by fitting
differential cross sections in a simple parameterization where amplitudes
contain resonant contributions and smooth background. The D_2 wave is dominated
by the f_2(1270) meson whose parameters are consistent with the with the
current world averages. The D_0 wave contains a f_2(1270) component, whose
fraction is fitted. For the S wave, the f_0(980) parameters are found to be
consistent with the values determined from our recent pi^+ pi^- data. In
addition to the f_0(980), the S wave prefers to have another resonance-like
contribution whose parameters are obtained.",0805.3387v2
2009-04-16,Collision of Multimode Dromions and a Firewall in the Two Component Long Wave Short Wave Resonance Interaction Equation,"In this paper, we investigate the two component long wave short wave
resonance interaction (2CLSRI) equation and show that it admits the Painleve
property. We then suitably exploit the recently developed truncated Painleve
approach to generate exponentially localized solutions for the short wave
components $S^{(1)}$ and $S^{(2)}$ while the long wave L admits line soliton
only. The exponentially localized solutions driving the short waves $S^{(1)}$
and $S^{(2)}$ in the y direction are endowed with different energies
(intensities) and are called ""multimode dromions"". We also observe that the
multimode dromions suffer intramodal inelastic collision while the existence of
a firewall across the modes prevents the switching of energy between the modes.",0904.2434v1
2015-03-03,Acoustic wave front reversal in a three-phase media,"Acoustic wave front conjugation is studied in a sandy marine sediment that
contains air bubbles in its fluid fraction. The considered phase conjugation is
a four-wave nonlinear parametric sound interaction process caused by nonlinear
bubble oscillations which are known to be dominant in acoustic nonlinear
interactions in three-phase marine sediments. Two various mechanisms of phase
conjugation are studied. One of them is based on the stimulated Raman-type
sound scattering on resonance bubble oscillations. The second one is associated
with sound interactions with bubble oscillations which frequencies are far from
resonance bubble frequencies. Nonlinear equations to solve the wave-front
conjugation problem are derived, expressions for acoustic wave amplitudes with
a reversed wave front are obtained and compared for various frequencies of the
excited bubble oscillations.",1503.00869v2
2017-09-11,Comparison of damping mechanisms for transverse waves in solar coronal loops,"We present a method to assess the plausibility of alternative mechanisms to
explain the damping of magnetohydrodynamic (MHD) transverse waves in solar
coronal loops. The considered mechanisms are resonant absorption of kink waves
in the Alfv\'en continuum, phase-mixing of Alfv\'en waves, and wave leakage.
Our methods make use of Bayesian inference and model comparison techniques. We
first infer the values for the physical parameters that control the wave
damping, under the assumption of a particular mechanism, for typically observed
damping time-scales. Then, the computation of marginal likelihoods and Bayes
factors enable us to quantify the relative plausibility between the alternative
mechanisms. We find that, in general, the evidence is not large enough to
support a single particular damping mechanism as the most plausible one.
Resonant absorption and wave leakage offer the most probable explanations in
strong damping regimes, while phase mixing is the best candidate for
weak/moderate damping. When applied to a selection of 89 observed transverse
loop oscillations, with their corresponding measurements of damping times
scales and taking into account data uncertainties, we find that only in a few
cases positive evidence for a given damping mechanism is available.",1709.03347v1
2019-06-18,Axisymmetric internal wave transmission and resonance in non-linear stratifications,"To date, the influence of non-linear stratifications and two layer
stratifications on internal wave propagation has been studied for
two-dimensional wave fields in a cartesian geometry. Here, we use a novel wave
generator configuration to investigate transmission in non-linear
stratifications of axisymmetric internal wave. Two configurations are studied,
both theoretically and experimentally. In the case of a free incident wave, a
transmission maximum is found in the vicinity of evanescent frequencies. In the
case of a confined incident wave, resonant effects lead to enhanced
transmission rates from an upper layer to layer below. We consider the
oceanographic relevance of these results by applying them to an example oceanic
stratification, finding that there can be real-world implications.",1906.07844v1
2019-03-24,Non-interacting gravity waves on the surface of a deep fluid,"We study the interaction of gravity waves on the surface of an infinitely
deep ideal fluid. Starting from Zakharov's variational formulation for water
waves we derive an expansion of the Hamiltonian to an arbitrary order, in a
manner that avoids a laborious series reversion associated with expressing the
velocity potential in terms of its value at the free surface. The expansion
kernels are shown to satisfy a recursion relation enabling us to draw some
conclusions about higher-order wave-wave interaction amplitudes, without
referring to the explicit forms of the individual lower-order kernels. In
particular, we show that unidirectional waves propagating in a two-dimensional
flow do not interact nonlinearly provided they fulfill the energy-momentum
conservation law. Switching from the physical variables to the so-called normal
variables we explain the vanishing of the amplitudes of fourth- and certain
fifth-order non-generic resonant interactions reported earlier and outline a
procedure for finding the one-dimensional wave vector configurations for which
the higher order interaction amplitudes become zero on the resonant
hypersurfaces.",1903.10854v1
2020-03-09,Total reflection of two guided waves for embedded trapped modes,"To investigate the mechanism of wave trapping, acoustic embedded trapped
modes associated with two-resonant-mode interference in two-dimensional
duct-cavity structures are calculated by the feedback-loop closure principle,
which allows us to analyse the travelling modes that construct the trapped
modes. The exact two coexisting resonant modes that underpin an embedded
trapped mode in a cavity open to two semi-infinite ducts are numerically
demonstrated. At the interface between the cavity segment and a duct, total
reflection can occur for a particular combination of two propagative guided
waves in the cavity. With a particular cavity length and a particular
frequency, total reflection also happens for the two reflected waves at the
opposite end of the cavity. In this way, the two coexisting standing waves
underpin a trapped mode. It is found that the two standing waves are not two
closed-cavity modes. Thus, this work presents a new understanding of such
embedded trapped modes as a product of total reflection of two guided waves at
the interface between two waveguides, rather than interference between two
eigenmodes of a closed cavity. For quasi-trapped modes, the Fano scattering
phenomenon owing to the effects of two acoustic channels is also shown.",2003.04172v1
2019-01-17,Laboratory investigations on the resonant feature of `dead water' phenomenon,"Interfacial internal wave excitation in the wake of towed ships is studied
experimentally in a quasi-two layer fluid. At a critical `resonant' towing
velocity, whose value depends on the structure of the vertical density profile,
the amplitude of the internal wave train following the ship reaches a maximum,
in unison with the development of a drag force acting on the vessel, known in
the maritime literature as `dead water'. The amplitudes and wavelengths of the
emerging internal waves are evaluated for various ship speeds, ship lengths and
stratification profiles. The results are compared to linear two- and
three-layer theories of freely propagating waves and lee waves. We find that
despite the fact that the observed internal waves can have considerable
amplitudes, linear theories can still provide a surprisingly adequate
description of subcritical-to-supercritical transition and the associated
amplification of internal waves.",1901.05931v1
2021-03-16,Elastic Bound State in the Continuum with Perfect Mode Conversion,"The partial or complete confinement of waves in an open system is omnipresent
in nature and in wave-based materials and technology. Here, we theoretically
analyze and experimentally observe the formation of a trapped mode with perfect
mode conversion (TMPC) between flexural waves and longitudinal waves, by
achieving a quasi-bound state in the continuum (BIC) in an open elastic wave
system. The latter allows a quasi-BIC in a semi-infinite background plate when
Fano resonance hybridizes flexural and longitudinal waves and balances their
radiative decay rates. We demonstrate that when the Fabry-P\'erot resonance of
the longitudinal wave is realized simultaneously, the TMPC formed by the
elastic BIC approaches infinite quality factor. Furthermore, we show that
quasi-BIC can be tuned continuously to BIC through the critical frequency of
mode conversion, which offers the possibility of TMPC with an arbitrarily high
quality factor. Our reported concept and physical mechanism open new routes to
achieve perfect mode conversion with tunable high quality factor in elastic
systems.",2103.09006v1
2024-01-15,Real-time imaging of standing-wave patterns in microresonators,"Real-time characterization of microresonator dynamics is important for many
applications. In particular it is critical for near-field sensing and
understanding light-matter interactions. Here, we report camera-facilitated
imaging and analysis of standing wave patterns in optical ring resonators. The
standing wave pattern is generated through bi-directional pumping of a
microresonator and the scattered light from the microresonator is collected by
a short-wave infrared (SWIR) camera. The recorded scattering patterns are
wavelength dependent, and the scattered intensity exhibits a linear relation
with the circulating power within the microresonator. By modulating the
relative phase between the two pump waves, we can control the generated
standing waves movements and characterize the resonator with the SWIR camera.
The visualized standing wave enables subwavelength distance measurements of
scattering targets with nanometer-level accuracy. This work opens new avenues
for applications in on-chip near-field (bio-)sensing, real time
characterization of photonic integrated circuits and backscattering control in
telecom systems.",2401.07670v1
2005-12-09,Time Minimal Trajectories for a Spin 1/2 Particle in a Magnetic Field,"In this paper we consider the minimum time population transfer problem for
the $z$-component of the spin of a (spin 1/2) particle driven by a magnetic
field, controlled along the x axis, with bounded amplitude. On the Bloch sphere
(i.e. after a suitable Hopf projection), this problem can be attacked with
techniques of optimal syntheses on 2-D manifolds. Let $(-E,E)$ be the two
energy levels, and $|\Omega(t)|\leq M$ the bound on the field amplitude. For
each couple of values $E$ and $M$, we determine the time optimal synthesis
starting from the level $-E$ and we provide the explicit expression of the time
optimal trajectories steering the state one to the state two, in terms of a
parameter that can be computed solving numerically a suitable equation. For
$M/E<<1$, every time optimal trajectory is bang-bang and in particular the
corresponding control is periodic with frequency of the order of the resonance
frequency $\omega_R=2E$. On the other side, for $M/E>1$, the time optimal
trajectory steering the state one to the state two is bang-bang with exactly
one switching. Fixed $E$ we also prove that for $M\to\infty$ the time needed to
reach the state two tends to zero. In the case $M/E>1$ there are time optimal
trajectories containing a singular arc. Finally we compare these results with
some known results of Khaneja, Brockett and Glaser and with those obtained by
controlling the magnetic field both on the $x$ and $y$ directions (or with one
external field, but in the rotating wave approximation). As byproduct we prove
that the qualitative shape of the time optimal synthesis presents different
patterns, that cyclically alternate as $M/E\to0$, giving a partial proof of a
conjecture formulated in a previous paper.",0512074v2
2018-09-19,"Singlet $s^\pm$-wave pairing in quasi-one-dimensional ACr$_3$As$_3$ (A=K, Rb, Cs) superconductors","The recent discovery of quasi-one-dimensional Chromium-based
superconductivity has generated much excitement. We study in this work the
superconducting instabilities of a representative compound, the newly
synthesized KCr$_3$As$_3$ superconductor. Based on inputs from density
functional theory calculations, we first construct an effective multi-orbital
tight-binding Hamiltonian to model its low-energy band structure. We then
employ standard random-phase approximation calculations to investigate the
superconducting instabilities of the resultant multi-orbital Hubbard model. We
find various pairing symmetries in the phase diagram in different interaction
parameter regimes, including the triplet $f$-wave, $p_z$-wave and singlet
$s^\pm$-wave pairings. We argue that the singlet $s^\pm$-wave pairing, which
emerges at intermediate interaction strength, is realized in this material.
This singlet pairing is driven by spin-density wave fluctuations enhanced by
Fermi-surface nesting. We point out that phase-sensitive measurement can
distinguish the $s$-wave pairing in KCr$_3$As$_3$ from the $p_z$-wave
previously proposed for a related compound K$_2$Cr$_3$As$_3$. The
$s^{\pm}$-wave pairing in KCr$_3$As$_3$ shall also exhibit a subgap spin
resonance mode near the nesting vector, which can be tested by inelastic
neutron scattering measurements. Another intriguing property of the
$s^\pm$-pairing is that it can induce time-reversal invariant topological
superconductivity in a semiconductor wire with large Rashba spin-orbit coupling
via proximity effect. Our study shall be of general relevance to all
superconductors in the family of ACr$_3$As$_3$ (A=K, Rb, Cs).",1809.07117v3
2018-12-17,Gravitational waveforms from SpEC simulations : neutron star-neutron star and low-mass black hole-neutron star binaries,"Gravitational waveforms from numerical simulations are a critical tool to
test and analytically calibrate the waveform models used to study the
properties of merging compact objects. In this paper, we present a series of
high-accuracy waveforms produced with the SpEC code for systems involving at
least one neutron star. We provide for the first time waveforms with sub-radian
accuracy over more than twenty cycles for low-mass black hole-neutron star
binaries, including binaries with non-spinning objects, and binaries with
rapidly spinning neutron stars that maximize the impact on the gravitational
wave signal of the near-resonant growth of the fundamental excitation mode of
the neutron star (f-mode). We also provide for the first time with SpEC a
high-accuracy neutron star-neutron star waveform. These waveforms are made
publicly available as part of the SxS catalogue. We compare our results to
analytical waveform models currently implemented in data analysis pipelines.
For most simulations, the models lie outside of the predicted numerical errors
in the last few orbits before merger, but do not show systematic deviations
from the numerical results: comparing different models appears to provide
reasonable estimates of the modeling errors. The sole exception is the
equal-mass simulation using a rapidly counter-rotating neutron star to maximize
the impact of the excitation of the f-mode, for which all models perform
poorly. This is however expected, as even the single model that takes f-mode
excitation into account ignores the significant impact of the neutron star spin
on the f-mode excitation frequency.",1812.06988v1
2020-09-25,Strain-engineering of the charge and spin-orbital interactions in Sr2IrO4,"In the high spin-orbit coupled Sr2IrO4, the high sensitivity of the ground
state to the details of the local lattice structure shows a large potential for
the manipulation of the functional properties by inducing local lattice
distortions. We use epitaxial strain to modify the Ir-O bond geometry in
Sr2IrO4 and perform momentum-dependent Resonant Inelastic X-ray Scattering
(RIXS) at the metal and at the ligand sites to unveil the response of the low
energy elementary excitations. We observe that the pseudospin-wave dispersion
for tensile-strained Sr2IrO4 films displays large softening along the [h,0]
direction, while along the [h,h] direction it shows hardening. This evolution
reveals a renormalization of the magnetic interactions caused by a
strain-driven crossover from anisotropic to isotropic interactions between the
magnetic moments. Moreover, we detect dispersive electron-hole pair excitations
which shift to lower (higher) energies upon compressive (tensile) strain,
manifesting a reduction (increase) in the size of the charge gap. This behavior
shows an intimate coupling between charge excitations and lattice distortions
in Sr2IrO4, originating from the modified hopping elements between the t2g
orbitals. Our work highlights the central role played by the lattice degrees of
freedom in determining both the pseudospin and charge excitations of Sr2IrO4
and provides valuable information towards the control of the ground state of
complex oxides in the presence of high spin-orbit coupling.",2009.12262v1
2021-05-18,Computational Micromagnetics based on Normal Modes: bridging the gap between macrospin and full spatial discretization,"The Landau-Lifshitz equation governing magnetization dynamics is written in
terms of the amplitudes of normal modes associated with the micromagnetic
system's appropriate ground state. This results in a system of nonlinear
ordinary differential equations (ODEs), the right-hand side of which can be
expressed as the sum of a linear term and nonlinear terms with increasing order
of nonlinearity (quadratic, cubic, etc.). The application of the method to
nanostructured magnetic systems demonstrates that the accurate description of
magnetization dynamics requires a limited number of normal modes, which results
in a considerable improvement in computational speed. The proposed method can
be used to obtain a reduced-order dynamical description of magnetic
nanostructures which allows to adjust the accuracy between low-dimensional
models, such as macrospin, and micromagnetic models with full spatial
discretization. This new paradigm for micromagnetic simulations is tested for
three problems relevant to the areas of spintronics and magnonics: directional
spin-wave coupling in magnonic waveguides, high power ferromagnetic resonance
in a magnetic nanodot, and injection-locking in spin-torque nano-oscillators.
The case studies considered demonstrate the validity of the proposed approach
to systematically obtain an intermediate order dynamical model based on normal
modes for the analysis of magnetic nanosystems. The time-consuming calculation
of the normal modes has to be done only one time for the system. These modes
can be used to optimize and predict the system response for all possible
time-varying external excitations (magnetic fields, spin currents). This is of
utmost importance for applications where fast and accurate system simulations
are required, such as in electronic circuits including magnetic devices.",2105.08829v2
2022-07-29,Non-linear magnons and exchange Hamiltonians of delafossite proximate quantum spin liquids,"Quantum spin liquids (QSL) are theoretical states of matter with long-range
entanglement and exotic quasiparticles. However, they generally elude
quantitative theory, rendering their underlying phases mysterious and hampering
efforts to identify experimental QSL states. Here we study triangular lattice
resonating valence bond QSL candidate materials KYbSe$_2$ and NaYbSe$_2$. We
measure the magnon modes in their 1/3 plateau phase, where quantitative theory
is tractable, using inelastic neutron scattering and fit them using nonlinear
spin wave theory. We also fit the KYbSe$_2$ heat capacity using high
temperature series expansion. Both KYbSe$_2$ fits yield the same magnetic
Hamiltonian to within uncertainty, confirming previous estimates and showing
the Heisenberg $J_2/J_1$ to be an accurate model for these materials. Most
importantly, comparing KYbSe$_2$ and NaYbSe$_2$ shows that smaller $A$-site
Na$^+$ ion has a larger $J_2/J_1$ ratio. However, hydrostatic pressure applied
to KYbSe$_2$ increases the ordering temperature (a result consistent with
density functional theory calculations), indicating that pressure decreases
$J_2/J_1$. These results show how periodic table and hydrostatic pressure can
tune the $A$YbSe$_2$ materials in a controlled way.",2207.14785v3
2024-04-02,Spin and bond-charge excitation spectra in correlated electron systems near antiferromagnetic phase,"Magnetic and bond-charge interactions can arise from the same microscopic
interaction. Motivated by this observation, we compute magnetic and bond-charge
excitation spectra on an equal footing by introducing a simple effective model
on a square lattice, which describes antiferromagnetic and d-wave
superconducting phases around half-filling on the electron-doped side. The
magnetic excitation spectrum Im chi(q, omega) has strong weight around q=(pi,
pi) in low energy and its intensity map exhibits a pencil-tip-like shape in
q-omega space. Around q=(0,0) magnetic excitations show a steep dispersion
toward the (pi, pi) and (pi,0) directions, which is very similar to a spin-wave
dispersion although the system is non-magnetic. Bond-charge excitations are
characterized by four different symmetries and studied for all possible
couplings. Bond-charge fluctuations with three different symmetries have large
spectral weight around q=(pi, pi) in a relatively low-energy region and extend
widely more than the magnetic excitation spectrum. The d-wave symmetry of
bond-charge excitations also has sizable spectral weight along the direction
(pi/2, pi/2)-(0, 0)-(pi/2, 0) in a low-energy region and exhibits softening
around q approx (0.5 pi, 0), whereas no such softening is present in the other
symmetries. These results capture the essential features observed in
electron-doped cuprates and may motivate an experimental test of bond-charge
excitations around q=(pi, pi) on top of the strong magnetic excitations there
as well as additional softening in the d-wave channel in the (pi, pi)-(pi/2,
pi/2) region at low temperatures near the magnetic phase. We extend the present
analysis to the hole-doped side and highlight a contrast to the electron-doped
side, which includes incommensurate correlations, electronic nematic
correlations, and spin and bond-charge resonance modes in the superconducting
state.",2404.02219v1
2015-08-31,Interaction driven exotic quantum phases in spin-orbit coupled spin$-1$ bosons,"We study the interplay between large-spin, spin-orbit coupling, and
superfluidity for bosons in a two dimensional optical lattice, focusing on the
spin-1 spin-orbit coupled system recently realized at the Joint Quantum
Institute [Campbell et. al., arXiv:1501.05984]. We find a rich quantum phase
diagram, where, in addition to the conventional phases ---superfluid and
insulator--- contained in the spin-$1$ Bose-Hubbard model, there are new
lattice symmetry breaking phases. For weak interactions, the interplay between
two length scales, the lattice momentum and the spin-orbit wave-vector induce a
phase transition from a uniform superfluid to a phase where bosons
simultaneously condense at the center and edge of the Brillouin zone at a
non-zero spin-orbit strength. This state is characterized by spin density wave
order, which arises from the spin-$1$ nature of the system. Interactions
suppress spin density wave order, and favor a superfluid \textit{only} at the
Brillouin zone edge. This state has spatially oscillating mean field order
parameters, but a homogeneous density. We show that the spin density wave
superfluid phase survives in a two dimensional harmonic trap, and thus
establish that our results are directly applicable to experiments on $^{87}$Rb,
$^7$Li, and $^{41}$K.",1509.00005v2
2021-09-29,Prospects for measuring off-axis spins of binary black holes with Plus-era gravitational-wave detectors,"The mass and spin properties of binary black holes (BBHs) inferred from their
gravitational-wave signatures reveal important clues about how these systems
form. BBHs originating from isolated binary evolution are expected to have
spins preferentially aligned with their orbital angular momentum, whereas there
is no such preference in binaries formed via dynamical assembly. The fidelity
with which near-future gravitational-wave detectors can measure off-axis spins
will have implications for the study of BBH formation channels. In this work,
we examine the degree to which the Advanced LIGO Plus (A+) and Advanced Virgo
Plus (AdV+) interferometric detectors can measure both aligned and misaligned
spins. We compare spin resolution between the LIGO-Virgo network operating at
either A+/AdV+ (""Plus"") sensitivity or Advanced-era design (""Design"")
sensitivity using simulated BBH gravitational-wave signals injected into
synthetic detector noise. The signals are distributed over the mass-spin
parameter space of likely BBH systems, accounting for the effects of precession
and higher-order modes. We find that the Plus upgrades yield significant
improvements in spin estimation for systems with unequal masses and moderate or
large spins. Using simulated signals modelled after different types of
hierarchical BBH mergers, we also conclude that the Plus detector network will
yield substantially improved spin estimates for 1G+2G binaries compared to the
Design network.",2109.14571v2
2023-05-15,Tidal Spin-up of Black Hole Progenitor Stars,"Gravitational wave observations indicate the existence of merging black holes
(BHs) with high spin ($a\gtrsim0.3$), whose formation pathways are still an
open question. A possible way to form those binaries is through the tidal
spin-up of a Wolf-Rayet (WR) star by its BH companion. In this work, we
investigate this scenario by directly calculating the tidal excitation of
oscillation modes in WR star models, determining the tidal spin-up rate, and
integrating the coupled spin-orbit evolution for WR-BH binaries. We find that,
for short-period orbits and massive WR stars, the tidal interaction is mostly
contributed by standing gravity modes, in contrast to Zahn's model of traveling
waves which is frequently assumed in the literature. The standing modes are
less efficiently damped than traveling waves, meaning that prior estimates of
tidal spin-up may be overestimated. We show that tidal synchronization is
rarely reached in WR-BH binaries, and the resulting BH spins have $a \lesssim
0.4$ for all but the shortest-period ($P_{\rm orb} \! \lesssim 0.5 \, {\rm d}$)
binaries. Tidal spin-up in lower-mass systems is more efficient, providing an
anticorrelation between the mass and spin of the BHs, which could be tested in
future gravitational wave data. Nonlinear damping processes are poorly
understood but may allow for more efficient tidal spin-up. We also discuss a
new class of gravito-thermal modes that appear in our calculations.",2305.08356v2
2024-04-06,Spin-charge-lattice coupling across the charge density wave transition in a Kagome lattice antiferromagnet,"Understanding spin and lattice excitations in a metallic magnetic ordered
system form the basis to unveil the magnetic and lattice exchange couplings and
their interactions with itinerant electrons. Kagome lattice antiferromagnet
FeGe is interesting because it displays rare charge density wave (CDW) deep
inside the antiferromagnetic ordered phase that interacts with the magnetic
order. We use neutron scattering to study the evolution of spin and lattice
excitations across the CDW transition $T_{\rm CDW}$ in FeGe. While spin
excitations below $\sim$100 meV can be well described by spin waves of a spin-1
Heisenberg Hamiltonian, spin excitations at higher energies are centered around
the Brillouin zone boundary and extend up to $\sim180$ meV consistent with
quasiparticle excitations across spin-polarized electron-hole Fermi surfaces.
Furthermore, $c$-axis spin wave dispersion and Fe-Ge optical phonon modes show
a clear hardening below $T_{\rm CDW}$ due to spin-charge-lattice coupling but
with no evidence for a phonon Kohn anomaly. By comparing our experimental
results with density functional theory calculations in absolute units, we
conclude that FeGe is a Hund's metal in the intermediate correlated regime
where magnetism has contributions from both itinerant and localized electrons
arising from spin polarized electronic bands near the Fermi level.",2404.04459v1
2003-02-11,"Resonant interaction between gravitational waves, electromagnetic waves and plasma flows","In magnetized plasmas gravitational and electromagnetic waves may interact
coherently and exchange energy between themselves and with plasma flows. We
derive the wave interaction equations for these processes in the case of waves
propagating perpendicular or parallel to the plasma background magnetic field.
In the latter case, the electromagnetic waves are taken to be circularly
polarized waves of arbitrary amplitude. We allow for a background drift flow of
the plasma components which increases the number of possible evolution
scenarios. The interaction equations are solved analytically and the
characteristic time scales for conversion between gravitational and
electromagnetic waves are found. In particular, it is shown that in the
presence of a drift flow there are explosive instabilities resulting in the
generation of gravitational and electromagnetic waves. Conversely, we show that
energetic waves can interact to accelerate particles and thereby \emph{produce}
a drift flow. The relevance of these results for astrophysical and cosmological
plasmas is discussed.",0302039v2
2010-05-12,Observation of nonlinear dispersion relation and spatial statistics of wave turbulence on the surface of a fluid,"We report experiments on gravity-capillary wave turbulence on the surface of
a fluid. The wave amplitudes are measured simultaneously in time and space
using an optical method. The full space-time power spectrum shows that the wave
energy is localized on several branches in the wave-vector-frequency space. The
number of branches depend on the power injected within the waves. The
measurement of the nonlinear dispersion relation is found to be well described
by a law suggesting that the energy transfer mechanisms involved in wave
turbulence are not only restricted to purely resonant interaction between
nonlinear waves. The power-law scaling of the spatial spectrum and the
probability distribution of the wave amplitudes at a given wave number are also
measured and compared to the theoretical predictions.",1005.2000v2
2013-01-07,Electromagnetic waves destabilized by runaway electrons in near-critical electric fields,"Runaway electron distributions are strongly anisotropic in velocity space.
This anisotropy is a source of free energy that may destabilize electromagnetic
waves through a resonant interaction between the waves and the energetic
electrons. In this work we investigate the high-frequency electromagnetic waves
that are destabilized by runaway electron beams when the electric field is
close to the critical field for runaway acceleration. Using a runaway electron
distribution appropriate for the near-critical case we calculate the linear
instability growth rate of these waves and conclude that the obliquely
propagating whistler waves are most unstable. We show that the frequencies,
wave numbers and propagation angles of the most unstable waves depend strongly
on the magnetic field. Taking into account collisional and convective damping
of the waves, we determine the number density of runaways that is required to
destabilize the waves and show its parametric dependences.",1301.1250v1
2015-04-10,Topological water wave state in a one-dimensional structure,"Topological concepts have been introduced into electronic, photonic, and
phononic systems, but have not been studied in surface-water-wave systems. Here
we study a one-dimensional periodic resonant surface-water-wave system and
demonstrate its topological transition. By selecting three different water
depths, we can construct different types of water waves - shallow, intermediate
and deep water waves. The periodic surface-water-wave system consists of an
array of cylindrical water tanks connected with narrow water channels. As the
width of connecting channel varies, the band diagram undergoes a topological
transition which can be further characterized by Zak phase. This topological
transition holds true for shallow, intermediate and deep water waves. However,
the interface state at the boundary separating two topologically distinct
arrays of water tanks can exhibit different bands for shallow, intermediate and
deep water waves. Our work studies for the first time topological properties of
water wave systems, and paves the way to potential management of water waves.",1504.02655v2
2019-11-28,Generalized modulation theory for strongly nonlinear gravity waves in a compressible atmosphere,"This study investigates nonlinear gravity waves in the compressible
atmosphere from the Earth's surface to the deep atmosphere. These waves are
effectively described by Grimshaw's dissipative modulation equations which
provide the basis for finding stationary solutions such as mountain lee waves
and testing their stability in an analytic fashion. Assuming energetically
consistent boundary and far-field conditions, that is no energy flux through
the surface, free-slip boundary, and finite total energy, general wave
solutions are derived and illustrated in terms of realistic background fields.
These assumptions also imply that the wave-Reynolds number must become less
than unity above a certain height. The modulational stability of admissible,
both non-hydrostatic and hydrostatic, waves is examined. It turns out that,
when accounting for the self-induced mean flow, the wave-Froude number has a
resonance condition. If it becomes $1/\sqrt{2}$, then the wave destabilizes due
to perturbations from the essential spectrum of the linearized modulation
equations. However, if the horizontal wavelength is large enough, waves
overturn before they can reach the modulational stability condition.",1911.12669v2
2017-06-18,Extreme driven ion acoustic waves,"Excitation of large amplitude strongly nonlinear ion acoustic waves from a
trivial equilibrium by a chirped frequency drive is discussed. Under certain
conditions, after passage through the linear resonance in this system, the
nonlinearity and the variation of parameters work in tandem to preserve the
phase-locking with the driving wave via excursion of the excited ion acoustic
wave in its parameter space, yielding controlled growth of the wave amplitude.
We study these autoresonant waves via a fully nonlinear warm fluid model and
predict formation of sharply peaked (extreme) ion acoustic excitations with
local ion density significantly exceeding the unperturbed plasma density. The
driven wave amplitude is bounded by the kinetic wave-breaking, as the local
maximum fluid velocity of the wave approaches the phase velocity of the drive.
The Vlasov-Poisson simulations are used to confirm the results of the fluid
model and the Whitham's averaged variational principle is applied in analyzing
evolution of the autoresonant ion acoustic waves.",1706.05660v1
2020-09-11,Free vibration and wave power reflection in Mindlin rectangular plates via exact wave propagation approach,"Reflection, propagation and energy analysis are crucially important in
designing structures, especially plates. A thick plate is considered based on
first order shear deformation theory. Wave Propagation Method (WPM) is employed
to exactly derive resonant frequencies and wave power reflection from different
classical boundary conditions. Firstly, the frequency results are compared with
other literature to validate the exact proposed wave solution in the present
work. Then, wave analysis and benchmark results for natural frequencies are
presented for six different combinations of boundary conditions. The results
indicate that the wave power reflection of thick rectangular plates is quite
complicated and an incident wave of a specific type gives rise to other types
of waves except for simply supported boundary conditions where the reflected
wave power does not depend on the system parameters.",2009.05597v1
2019-12-19,Heavy Ion Acceleration by Super-Alfvenic Waves,"A generation mechanism of super Alfv\'{e}nic (SPA) waves in multi-ion species
plasma is proposed and the associated heavy ion acceleration process is
discussed. The SPA waves are thought to play important roles in particle
acceleration since they have large wave electric field because of their high
phase velocity. It is demonstrated by using full particle-in-cell simulation
that large amplitude proton cyclotron waves, excited due to proton temperature
anisotropy, nonlinearly destabilize SPA waves through parametric decay
instability in a three component plasma composed of electrons, protons, and
$\alpha$ particles. At the same time, $\alpha$ cyclotron waves get excited via
another decay instability. A pre-accelerated $\alpha$ particle resonates
simultaneously with the two daughter waves, the SPA waves and the $\alpha$
cyclotron waves, and it is further accelerated perpendicular to the ambient
magnetic field. The process may work in astrophysical environments where
sufficiently large temperature anisotropy of lower mass ions occurs.",2001.02538v1
2022-06-03,Conservation of Total Wave Action in the Expanding Solar Wind,"The conservation of wave action in moving plasmas has been well-known for
over half a century. However, wave action is not conserved when multiple wave
modes propagate and coexist close to degeneration condition (Sound speed equals
Alfv\'en speed, i.e. plasma $\beta \sim 1$). Here we show that the violation of
conservation is due to wave mode conversion, and that the total wave action
summed over interacting modes is still conserved. Though the result is general,
we focus on MHD waves and identify three distinctive mode conversion
mechanisms, i.e. degeneracy, linear mode conversion, and resonance, and provide
an intuitive physical picture for the mode conversion processes. We use 1D MHD
simulations with the Expanding Box Model to simulate the nonlinear evolution of
monochromatic MHD waves in the expanding solar wind. Simulation results
validate the theory; total wave action therefore remains an interesting
diagnostic for studies of waves and turbulence in the solar wind.",2206.01809v1
2022-08-01,Dimensionless solutions of the wave equation,"Plane waves are regarded as the general solution of the wave equation.
However the plane wave expansion of standing waves by means of complex phasors
leads to a theory in which the time coordinate does not receive the same
treatment as the three space coordinates. An equal treatment is possible using
our alternative approach built upon the dimensionless version of the wave
equation. As a result, the usual standing wave solution written as sum of plane
waves is just one of the available geometrical projections and therefore
removes a part of the available information. The existence of these alternative
projections and the constraints that they introduce, produce verifiable
consequences. We present an experimental verification of one of this
consequences by means of acoustic waves. In particular a resonant cavity is
radiated from an external source through a squared aperture. The predicted
flows of phase based on P\'olya potentials allow us to find the direction of
arrival without using temporal coordinates. Although this work is limited to
the wave equation, the background concept is the relationship between space and
time and therefore could have far reaching consequences in other physical
models.",2208.00551v1
2023-10-03,Observations of rogue seas in the Southern Ocean,"We report direct observations of surface waves from a stereo camera system
along with concurrent measurements of wind speed during an expedition across
the Southern Ocean in the austral winter aboard South African icebreaker
S.A.~Agulhas~II. Records include water surface elevation across a range of wave
conditions, spanning from early stages of wave growth to full development. We
give experimental evidence of rogue seas, i.e., sea states characterizided by
heavy tails of the probability density function well beyond the expectation
based on bound mode theory. These conditions emerge during wave growth, where
strong wind forcing and high nonlinearity drive wave dynamics. Quasi-resonance
wave-wave interactions, which are known to sustain the generation of large
amplitude rogue waves, capture this behaviour. Wave statistics return to
normality as the wind forcing ceases and waves switch to a full developed
condition.",2310.01841v2
2024-04-12,Non-uniform wave momentum bandgap in biaxial anisotropic photonic time crystals,"Photonic time crystals (PTCs) host momentum bandgaps enabling intriguing
non-resonant light amplification in propagating waves, but opening substantial
bandgaps demands refractive index changes too extreme for conventional
nonlinear optics. Here, we introduce momentum bandgaps for non-uniform waves,
including evanescent and ghost types, by extending PTCs to biaxial anisotropic
photonic time crystals that periodically alternate between uniform biaxial
anisotropy and isotropic media over time. We show that ghost waves, unlike
evanescent waves, sustain only momentum bandgaps, opening wide bandgaps at even
the smallest modulation depths. Moreover, we demonstrate momentum bandgap
effects on non-uniform waves that can be amplified, or through decaying modes,
selectively attenuated. We find that ghost wave momentum bandgaps uniquely
boost refracted over reflected waves under one-way incidence, in stark contrast
to balanced amplification seen in both propagating and evanescent waves. Our
approach expands time-varying metamaterials by integrating wave
characteristics, bridging the gap between conventional nonlinear optics and PTC
momentum bandgaps, and shedding new light on extreme manipulation of surface
polaritons.",2404.08206v1
2010-10-29,Influence of positional correlations on the propagation of waves in a complex medium with polydisperse resonant scatterers,"We present experimental results on a model system for studying wave
propagation in a complex medium exhibiting low frequency resonances. These
experiments enable us to investigate a fundamental question that is relevant
for many materials, such as metamaterials, where low-frequency scattering
resonances strongly influence the effective medium properties. This question
concerns the effect of correlations in the positions of the scatterers on the
coupling between their resonances, and hence on wave transport through the
medium. To examine this question experimentally, we measure the effective
medium wave number of acoustic waves in a sample made of bubbles embedded in an
elastic matrix over a frequency range that includes the resonance frequency of
the bubbles. The effective medium is highly dispersive, showing peaks in the
attenuation and the phase velocity as functions of the frequency, which cannot
be accurately described using the Independent Scattering Approximation (ISA).
This discrepancy may be explained by the effects of the positional correlations
of the scatterers, which we show to be dependent on the size of the scatterers.
We propose a self-consistent approach for taking this ""polydisperse
correlation"" into account and show that our model better describes the
experimental results than the ISA.",1010.6243v2
2018-12-19,Quick and repeatable shear modulus measurement based on torsional resonance and torsional wave propagation using a piezoelectric torsional transducer,"Shear modulus is one of the fundamental mechanical properties of materials,
while its quick and accurate measurement is still a challenge. Here we proposed
two methods for shear modulus measurement based on torsional resonance and
torsional wave propagation using a same piezoelectric torsional transducer.
Firstly, the torsional transducer was introduced which consists of two
thickness poled, thickness shear (d15) piezoelectric half-rings. Secondly, the
equivalent circuit of the transducer-cylindrical specimen system is derived and
the shear modulus can be explicitly obtained using the torsional resonance
frequency. The internal friction can also be obtained, which is calculated by
using an approximate formula. Then, the principle of shear modulus and internal
friction measurement based on torsional wave propagation were presented.
Finally, shear modulus and internal friction measurement on four materials
including 1045 steel, aluminum, quartz glass and PMMA, were conducted. Results
indicate that the measured shear moduli using these two methods are very close
to each other, and consistent with the reference values in literatures. The
resonance method is quite convenient and highly repeatable, but is typically
not suitable for long specimens where the first torsional resonance may not be
visible. The wave propagation method is especially suitable for long specimens
and high frequency measurement is suggested. The internal frictions measured by
these two methods were also close to each other, and the simple wave
attenuation method is suggested. The two shear modulus measurement methods
proposed in this work are quite reliable and can be widely used in near future.",1812.07784v1
2003-03-19,Wave function mapping conditions in Open Quantum Dots structures,"We discuss the minimal conditions for wave function spectroscopy, in which
resonant tunneling is the measurement tool. Two systems are addressed: resonant
tunneling diodes, as a toy model, and open quantum dots. The toy model is used
to analyze the crucial tunning between the necessary resolution in
current-voltage characteristics and the breakdown of the wave functions probing
potentials into a level splitting characteristic of double quantum wells. The
present results establish a parameter region where the wavefunction
spectroscopy by resonant tunneling could be achieved. In the case of open
quantum dots, a breakdown of the mapping condition is related to a change into
a double quantum dot structure induced by the local probing potential. The
analogy between the toy model and open quantum dots show that a precise control
over shape and extention of the potential probes is irrelevant for wave
function mapping. Moreover, the present system is a realization of a tunable
Fano system in the wave function mapping regime.",0303399v1
2008-01-02,Resonant Plasma Wave Growth and Monoenergetic Electron Beam Production using Collinear High-Intensity Ultrashort Laser Pulses,"The resonant generation of relativistic plasma waves and plasma wave guiding
by two co-propagating laser pulses has been studied. By proper timing between
guiding and driver pulses, a resonant interaction occurs, which generates a
high-amplitude plasma wave over a longer length than is possible with either of
the laser pulses individually. The growth of the plasma wave is inferred by the
measurement of monoenergetic electron beams with low divergence that are not
measured by using either of the pulses individually. This scheme can be easily
implemented, and allows more control of the interaction than is available to
the single pulse scheme.",0801.0410v1
2008-08-23,Nonlinear theory of resonant slow waves in anisotropic and dispersive plasmas,"The solar corona is a typical example of a plasma with strongly anisotropic
transport processes. The main dissipative mechanisms in the solar corona acting
on slow magnetoacoustic waves are the anisotropic thermal conductivity and
viscosity. Ballai et al. [Phys. Plasmas 5, 252 (1998)] developed the nonlinear
theory of driven slow resonant waves in such a regime. In the present paper the
nonlinear behaviour of driven magnetohydrodynamic waves in the slow dissipative
layer in plasmas with strongly anisotropic viscosity and thermal conductivity
is expanded by considering dispersive effects due to Hall currents. The
nonlinear governing equation describing the dynamics of nonlinear resonant slow
waves is supplemented by a term which describes nonlinear dispersion and is of
the same order of magnitude as nonlinearity and dissipation. The connection
formulae are found to be similar to their non-dispersive counterparts.",0808.3193v1
2012-05-24,Resonant acousto-optics in the terahertz range: TO-phonon polaritons driven by an ultrasonic wave,"The resonant acousto-optic effect is studied both analytically and
numerically in the terahertz range where the transverse-optical (TO) phonons
play the role of a mediator which strongly couples the ultrasound and light
fields. A propagating acoustic wave interacts with the TO phonons via
anharmonic channels and opens band gaps in the TO-phonon polariton energy
dispersion that results in pronounced Bragg scattering and reflection of the
incoming light. The separation in frequency of different Bragg replicas, which
is at the heart of acousto-optics, allows us to study the resonant
acousto-optic effect in the most simple and efficient geometry of collinear
propagation of electromagnetic and ultrasonic waves. The acoustically induced
energy gaps, Bragg reflection spectra, and the spatial distribution of the
electric field and polarization are calculated for CuCl parameters, in a wide
range of frequencies and intensities of the pumping acoustic wave. Our results
show drastic changes in terahertz spectra of semiconductor crystals that opens
the way for efficient and accessible manipulation of their infrared properties,
by tuning the parameters of the acoustic wave.",1205.5432v1
2013-06-26,Gravito-electromagnetic resonances in Minkowski space,"We consider the interaction between gravitational and electromagnetic
radiation propagating on a Minkowski background and look into the effects of
the former upon the latter. Not surprisingly, the coupling between these two
sources leads to gravitationally driven electromagnetic waves. At the second
perturbative level, the driving force appears as the superposition of two
waves, the properties of which are decided by the initial conditions. We find
that the Weyl-Maxwell interaction typically leads to electromagnetic beat-like
signals and, in some cases, to the resonant amplification of the driven
electromagnetic wave. For physically reasonable initial conditions, we show
that these resonances imply a linear (in time) growth for the amplitude of the
electromagnetic signal, with the overall amplification also depending on the
strength of the driving gravity wave. Finally, we provide order-of-magnitude
estimates of the achieved amplification by applying our analysis to
astrophysical environments where both gravitational and electromagnetic waves
are expected to coexist.",1306.6227v3
2015-11-17,Resonant X-ray Emission Spectroscopy With a Standing Wave Excitation,"The Borrmann effect is the anomalous transmission of x rays in perfect
crystals under diffraction conditions. It arises from the interference of the
incident and diffracted waves, which creates a standing wave with nodes at
strongly absorbing atoms. Dipolar absorption of x rays is thus diminished,
which makes the crystal nearly transparent for certain x-ray wave vectors.
Indeed, a relative enhancement of electric quadrupole absorption via the
Borrmann effect has been demonstrated recently. Here we show that the Borrmann
effect has a significantly larger impact on resonant x-ray emission than is
observable in x-ray absorption. Emission from a dipole forbidden intermediate
state may even dominate the corresponding x-ray spectra. Our work extends the
domain of x-ray standing wave methods to resonant x-ray emission spectroscopy
and provides means for novel spectroscopic experiments in d- and f-electron
systems.",1511.05354v2
2017-11-07,Asymmetric Nonlinear System is Not sufficient for Non-Reciprocal Quantum Wave Diode,"We demonstrate symmetric wave propagations in asymmetric nonlinear quantum
systems. By solving the nonlinear Sch\""ordinger equation, we first analytically
prove the existence of symmetric transmission in asymmetric systems with a
single nonlinear delta-function interface. We then point out that a finite
width of the nonlinear interface region is necessary to produce non-reciprocity
in asymmetric systems. However, a geometrical resonant condition for breaking
non-reciprocal propagation is then identified theoretically and verified
numerically. With such a resonant condition, the nonlinear interface region of
finite width behaves like a single nonlinear delta-barrier so that wave
propagations in the forward and backward directions are identical under
arbitrary incident wave intensity. As such, reciprocity re-emerges periodically
in the asymmetric nonlinear system when changing the width of interface region.
Finally, similar resonant conditions of discrete nonlinear Sch\""ordinger
equation are discussed. Therefore, we have identified instances of Reciprocity
Theorem that breaking spatial symmetry in nonlinear interface systems is not
sufficient to produce non-reciprocal wave propagation.",1711.02304v1
2020-02-27,Near-resonant instability of geostrophic modes: beyond Greenspan's theorem,"We explore the near-resonant interaction of inertial waves with geostrophic
modes in rotating fluids via numerical and theoretical analysis. When a single
inertial wave is imposed, we find that some geostrophic modes are unstable
above a threshold value of the Rossby number $kRo$ based on the wavenumber and
wave amplitude. We show this instability to be caused by triadic interaction
involving two inertial waves and a geostrophic mode such that the sum of their
eigen frequencies is non-zero. We derive theoretical scalings for the growth
rate of this near-resonant instability. The growth rate scaled by the global
rotation rate is proportional to $(kRo)^2$ at low $kRo$ and transitions to a
$kRo$ scaling for larger $kRo$. These scalings are in excellent agreement with
direct numerical simulations. This instability could explain recent
experimental observations of geostrophic instability driven by waves.",2002.12425v2
2020-12-25,Topological phases and bulk-edge correspondence of magnetized cold plasmas,"Plasmas have been recently studied as topological materials. However, a
comprehensive picture of topological phases and topological phase transitions
in cold magnetized plasmas is still missing. Here we systematically map out all
the topological phases and establish the bulk-edge correspondence in cold
magnetized plasmas. We find that for the linear eigenmodes, there are 10
topological phases in the parameter space of density $n$, magnetic field $B$,
and parallel wavenumber $k_{z}$, separated by the surfaces of Langmuir wave-L
wave resonance, Langmuir wave-cyclotron wave resonance, and zero magnetic
field. For fixed $B$ and $k_{z}$, only the phase transition at the Langmuir
wave-cyclotron wave resonance corresponds to edge modes. A sufficient and
necessary condition for the existence of this type of edge modes is given and
verified by numerical solutions. We demonstrate that edge modes exist not only
on a plasma-vacuum interface but also on more general plasma-plasma interfaces.
This finding broadens the possible applications of these exotic excitations in
space and laboratory plasmas.",2012.13611v2
2022-04-27,Alfvén waves: To the 80th anniversary of discovery,"The paper is dedicated to the anniversary of the discovery of Alfv\'en waves.
The concept of Alfv\'en waves has played an outstanding role in the formation
and development of cosmical electrodynamics. A distinctive feature of Alfv\'en
waves is that at each point in space the group velocity vector and the external
magnetic field vector are collinear to each other. As a result, Alfv\'en waves
can carry momentum, energy, and information over long distances. We briefly
describe two Alfv\'en resonators, one of which is formed in the ionosphere, and
the second presumably exists in the Earth's radiation belt. The existence of an
ionospheric resonator is justified theoretically and confirmed by numerous
observations. The second resonator is located between reflection points located
high above the Earth symmetrically with respect to the plane of the geomagnetic
equator. Keywords: Alfv\'en velocity, dispersion law, group velocity, geometric
optics, heavy ions.",2204.12700v1
2017-07-22,Transverse spinning of light with globally unique handedness,"Access to the transverse spin of light has unlocked new regimes in
topological photonics and optomechanics. To achieve the transverse spin of
nonzero longitudinal fields, various platforms that derive transversely
confined waves based on focusing, interference, or evanescent waves have been
suggested. Nonetheless, because of the transverse confinement inherently
accompanying sign reversal of the field derivative, the resulting transverse
spin handedness experiences spatial inversion, which leads to a mismatch
between the densities of the wavefunction and its spin component and hinders
the global observation of the transverse spin. Here, we reveal a globally pure
transverse spin in which the wavefunction density signifies the spin
distribution, by employing inverse molding of the eigenmode in the spin basis.
Starting from the target spin profile, we analytically obtain the potential
landscape and then show that the elliptic-hyperbolic transition around the
epsilon-near-zero permittivity allows for the global conservation of transverse
spin handedness across the topological interface between anisotropic
metamaterials. Extending to the non-Hermitian regime, we also develop
annihilated transverse spin modes to cover the entire Poincare sphere of the
meridional plane. Our results enable the complete transfer of optical energy to
transverse spinning motions and realize the classical analogy of 3-dimensional
quantum spin states.",1707.07099v1
2020-03-02,Higher-order Quantum Spin Hall Effect of Light,"Band topology and related spin (or pseudo-spin) physics of photons provide us
with a new dimension for manipulating light, which is potentially useful for
information communication and data storage. Especially, the quantum spin Hall
effect of light, where electromagnetic waves propagate along surfaces of
samples with strong spin-momentum locking, paves the way for achieving
topologically protected photonic spin transport. Recently, the conventional
bulk-edge correspondence of the band topology has been extended to higher-order
cases that enables the explorations of topological states with codimensions
larger than 1 such as hinge and corner states. Here, for the first time, we
demonstrate a higherorder quantum spin Hall effect of light by utilizing an
all-dielectric C6v-symmetric photonic crystal. We observe corner states with
opposite pseudospin polarizations at different corners owing to nontrivial
higher-order topology and finite spin-spin coupling. By applying the
spin-polarized excitation sources, we can selectively excite the corner states
at different spatial positions through spin-momentum-locked decaying edge
states, resembling the quantum spin Hall effect in a higher-order manner. Our
work which breaks the barriers between the spin photonics and higher-order
topology opens the frontiers for studying lower-dimensional spinful classical
surface waves and supports explorations in robust communications.",2003.00933v1
1996-02-28,Static and Dynamic Spin Structure Factors of Frustrated Heisenberg Antiferromagnet,"Using the modified spin-wave theory we calculate static and dynamic spin
structure factors in spin-liquid state of the J1-J2 model. The spectrum of
excitations in the vector channel is discussed. The developed technique can
also be applied to the t-J model describing copper oxide superconductors.",9602150v1
2006-02-07,Sublattice Asymmetric Reductions of Spin Values on Stacked Triangular Lattice Antiferromagnet CsCoBr$_3$,"We study the reductions of spin values of the ground state on a stacked
triangular antiferromagnet using the spin-wave approach. We find that the spin
reductions have sublattice asymmetry due to the cancellation of the molecular
field. The sublattice asymmetry qualitatively analyzes the NMR results of
CsCoBr$_3$.",0602165v1
2010-12-27,The multi-state CASPT2 spin-orbit method,"We propose the multi-state complete-active-space second-order perturbation
theory spin-orbit method (MS-CASPT2-SO) for electronic structure calculations.
It is a two-step spin-orbit coupling method that does not make use of energy
shifts and that intrinsically guarantees the correct characters of the small
space wave functions that are used to calculate the spin-orbit couplings, in
contrast with previous two-step methods.",1012.5572v1
2014-05-12,Spin spin interaction and the relativistic Rabi formula,"The interaction of an electromagnetic wave with spin (polarized light) and an
electron is computed. Specifically the spin flip probability is computed using
the Dirac equation for an electron trapped in a uniform magnetic field.",1405.2947v2
2001-09-25,Coherent control of nuclear spin isomers of molecules: The role of molecular motion,"Molecular center-of-mass motion is taken into account in the theory of
coherent control of nuclear spin isomers of molecules. It is shown that
infrared radiation resonant to the molecular rovibrational transition can
substantially enrich nuclear spin isomers and speed up their conversion rate.",0109063v1
2001-12-21,Enrichment of nuclear spin isomers by molecular coherent control,"Enrichment of nuclear spin isomers of molecules by infrared radiation
resonant to molecular rovibrational transition is considered. Special attention
is given to the enrichment by light-induced crossing of far separated ortho and
para states.",0112074v1
2001-05-25,A Quantum Full Adder for a Scalable Nuclear Spin Quantum Computer,"We demonstrate a strategy for implementation a quantum full adder in a spin
chain quantum computer. As an example, we simulate a quantum full adder in a
chain containing 201 spins. Our simulations also demonstrate how one can
minimize errors generated by non-resonant effects.",0105133v1
2009-05-04,Self-organized quantum transitions in a spin-electron coupled system,"We investigate quantum dynamics of the excited electronic states in the
double-exchange model at half-filling by solving coupled equations for the
quantum evolution of electrons and Landau-Lifshits-Gilbert equation for
classical spins. The non-adiabatic quantum transitions driving the relaxation
are coordinated through the self-organized space-time structure of the
electron/spin dynamics leading to a resonant precession analogous to the ESR
process.",0905.0311v1
2017-10-05,Nuclear spin dependence of time reversal invariance violating effects in neutron scattering,"The spin structure of parity violating and time reversal invariance violating
effects in neutron scattering is discussed. The explicit relations between
these effects are presented in terms of functions nuclear spins and neutron
partial widths of p-wave resonances.",1710.02193v2
2008-06-20,Penetration Depth of Transverse Spin Current in Ferromagnetic Metals,"The line width of the ferromagnetic resonance (FMR) spectrum of
Cu/CoFeB/Cu/Co/Cu is studied. Analyzing the FMR spectrum by the theory of spin
pumping, we determined the penetration depth of the transverse spin current in
the Co layer. The obtained penetration depth of Co is 1.7 nm.",0806.3315v1
2000-12-06,Dispersion of the neutron resonance in cuprate superconductors,"We argue that recently measured downward dispersion of the neutron resonance
peak in cuprate superconductors is naturally explained if the resonance is
viewed as a spin-1 collective mode in a d-wave superconductor. The reduction of
the resonant frequency away from the antiferromagnetic wave vector is a direct
consequence of the momentum dependence of the d-wave superconducting gap. When
the magnetic correlation length becomes large, the dispersion should become
magnon-like, i.e., curve upwards from (pi,pi).",0012065v2
2001-11-03,Random Resonators and Prelocalized Modes in Disordered Dielectric Films,"Areal density of disorder-induced resonators with a high quality factor,
$Q\gg 1$, in a film with fluctuating refraction index is calculated
theoretically. We demonstrate that for a given $kl>1$, where $k$ is the light
wave vector, and $l$ is the transport mean free path, when {\em on average} the
light propagation is diffusive, the likelihood for finding a random resonator
increases dramatically with increasing the correlation radius of the disorder.
Parameters of {\em most probable} resonators as functions of $Q$ and $kl$ are
found.",0111047v1
2002-04-10,Time-resolved impulse response of the magnetoplasmon resonance in a two-dimensional electron gas,"We have used optically excited ultrashort electrical pulses to measure the
magnetoplasmon resonance of a two-dimensional electron gas formed in an
AlGaAs/GaAs heterostructure at frequencies up to 200 gigahertz. This is
accomplished by incorporating the sample into a guided wave probe operating in
a pumped (^{3}He) system. We are able to detect the resonance by launching a
stimulus pulse in the guide, and monitoring the system response in a time
resolved pump-probe arrangement. Data obtained from measurements yield resonant
frequencies that agree with the magnetoplasmon dispersion relation.",0204229v1
2004-07-14,Electric coupling to the magnetic resonance of split ring resonators,"We study both theoretically and experimentally the transmission properties of
a lattice of split ring resonators (SRRs) for different electromagnetic (EM)
field polarizations and propagation directions. We find unexpectedly that the
incident electric field E couples to the magnetic resonance of the SRR when the
EM waves propagate perpendicular to the SRR plane and the incident E is
parallel to the gap-bearing sides of the SRR. This is manifested by a dip in
the transmission spectrum. A simple analytic model is introduced to explain
this interesting behavior.",0407369v1
2005-05-02,Engineering Fano resonances in discrete networks,"We study transmission properties of discrete networks composed of linear
arrays coupled to systems of N side defects, and demonstrate the basic
principles of the resonant scattering management through engineering Fano
resonances. We find exact solutions for the wave transmission coefficient and
reveal the conditions for the perfect reflections and transmissions due to
either destructive or constructive interferences. We associate these
reflections and transmissions with Fano resonances, and demonstrate how they
can be tuned by introducing nonlinear defects into the network.",0505023v2
1999-02-15,The role of resonances in non-leptonic hyperon decays,"We examine the importance of resonances for the non-leptonic hyperon decays
in the framework of chiral perturbation theory. Lower lying resonances are
included into the effective theory. Integrating out the heavy degrees of
freedom in the resonance saturation scheme generates higher order counterterms
in the effective Lagrangian, providing an estimate of the pertinent coupling
constants. A fit to the eight independent decay amplitudes that are not related
by isospin symmetry is performed and reasonable agreement for both s- and p-
waves is achieved.",9902351v1
2006-03-20,The piN --> etaN data demand the existence of N(1710) P11 resonance reducing the 1700 MeV continuum ambiguity,"In spite of prolonged polemics, the agreement on the existence of N(1710) P11
resonance has not until now been reached, and the Particle Data Group declares
it as a 3-star resonance only. We show that the proper inclusion of inelastic
channels in the coupled-channel formalism indisputably demands the existence of
N(1710) P11 state, and that it presumably stays ""hidden"" within the continuum
ambiguity of any typical single channel partial wave analyses. Consequently,
its Particle Data Group confidence rating should be raised to a 4-star
resonance.",0603144v1
2001-05-08,Spatial solitons in a pumped semiconductor resonator,"Bright and dark spatial solitons are observed in an optically pumped
semiconductor resonator. The pumping allows to considerably reduce the light
intensity necessary for the existence of the solitons and alleviates thermal
load problems. Experiments are found to agree with calculations based on a
simple large aperture semiconductor resonator model. The role of signs of the
absorptive and reactive nonlinearities for soliton existence are discussed in
relation with the nonlinear resonance effect, the tilted wave mechanism of
pattern formation, and the sign of the population inversion.",0105019v1
2007-03-13,Directional emission from weakly eccentric resonators,"It is shown that when a circular resonator is deformed in a nonintegrable
way, a symmetry breaking of escaping rays occurs which can dramatically
modulate the outgoing wave even for small perturbations. The underlying
mechanism does not occur in integrable models for which the ray families can be
computed exactly and is described in this Letter on the basis of canonical
perturbation theory. Emission from deformed resonators is currently of immense
practical interest in the context of whispering-gallery optical resonances of
dielectric cavities and the approach outlined here promises simple analytical
characterisations in the important case of small deformations.",0703022v2
2006-10-19,Real-time Skyrme TDHF dynamics of giant resonances,"Nuclear dynamics of giant resonances are investigated with the real-time
Skyrme TDHF method. The TDHF equation is explicitly linearized with respect to
variation of single-particle wave functions. The time evolution of transition
densities are calculated for giant dipole resonances. The time-dependent
densities of protons and neutrons suggest that the dynamics of giant dipole
resonance in neutron-rich nuclei are significantly different from that in
stable nuclei with N=Z.",0610078v1
2001-06-13,Scattering of positronium from singly ionized helium and appearing resonances,"The coupled-channel model [Phys. Rev. A {\bf 59}, 363 (1999)] that yields
converged low-energy phase shifts, and exact binding and resonance features in
Ps-H [Phys. Rev. A {\bf 59}, 2058 (1999)] is applied to study Ps-He$^+$
scattering. Similar to PsH, resonances appear in the S-, P-, D-, etc partial
waves in the Ps-He$^+$ system but in both the singlet and triplet scattering
channels. The latter signifies possible Rydberg states of $e^+$ around singlet
and triplet helium. The S-wave singlet resonance at 2.79 eV agrees to that
predicted earlier in $e^+$-He entrance channel (energy difference 16.64 eV) at
19.27 eV [Chem. Phys. Lett. {\bf 262}, 460 (1996)].",0106041v1
2002-10-11,Hexagonal dielectric resonators and microcrystal lasers,"We study long-lived resonances (lowest-loss modes) in hexagonally shaped
dielectric resonators in order to gain insight into the physics of a class of
microcrystal lasers. Numerical results on resonance positions and lifetimes,
near-field intensity patterns, far-field emission patterns, and effects of
rounding of corners are presented. Most features are explained by a
semiclassical approximation based on pseudointegrable ray dynamics and boundary
waves. The semiclassical model is also relevant for other microlasers of
polygonal geometry.",0210052v2
2006-12-27,Calculation of three-body resonances using slow-variable discretization coupled with complex absorbing potential,"We developed a method to calculate positions and widths of three-body
resonances. The method combines the hyperspherical adiabatic approach, slow
variable discretization method (Tolstikhin et al., J. Phys. B: At. Mol. Opt.
Phys. 29, L389 (1996)), and a complex absorbing potential. The method can be
used to obtain resonances having short-range or long-range wave functions. In
particular, we applied the method to obtain very shallow three-body Efimov
resonances for a model system (Nielsen et al., Phys. Rev. A 66, 012705 (2002)).",0612242v3
2002-10-02,The role of the buildup oscillations on the speed of resonant tunneling diodes,"The fastest tunneling response in double barrier resonant structures is
investigated by considering explicit analytic solutions of the time dependent
Schr\""{o}dinger equation. For cutoff initial plane waves, we find that the
earliest tunneling events consist on the emission of a series of propagating
pulses of the probability density governed by the buildup oscillations in the
quantum well. We show that the fastest tunneling response comes from the
contribution of incident carriers at energies different from resonance, and
that its relevant time scale is given by $\tau_r=\pi \hbar /| E-\epsilon | $,
where $\epsilon $ is the resonance energy and $E$ is the incidence energy.",0210012v1
2007-06-11,Resonances of the Quantum $δ$-Kicked Accelerator,"We report the observation of high order resonances of the quantum
$\delta$-kicked accelerator using a BEC kicked by a standing wave of light. The
signature of these resonances is the existence of quantum accelerator modes.
For the first time quantum accelerator modes were seen near 1/4 and 1/3 of the
Talbot time. Using a BEC enabled us to study the detailed structure of the
modes and resonances which are related to the fractional Talbot effect. We
present a general theory for this system and apply it to predict the behavior
of the accelerator modes.",0706.1587v1
2008-04-01,Optical combs with a crystalline whispering gallery mode resonator,"We report on the experimental demonstration of a tunable monolithic optical
frequency comb generator. The device is based on the four-wave mixing in a
crystalline calcium fluoride whispering gallery mode resonator. The frequency
spacing of the comb is given by an integer number of the free spectral range of
the resonator. We select the desired number by tuning the pumping laser
frequency with respect to the corresponding resonator mode. We also observe
interacting optical combs and high-frequency hyperparametric oscillation,
depending on the experimental conditions. A potential application of the comb
for generating narrowband frequency microwave signals is demonstrated.",0804.0263v1
2009-07-15,Acoustic characterization of Hofstadter butterfly with resonant scatterers,"We are interested in the experimental characterization of the Hofstadter
butterfly by means of acoustical waves. The transmission of an acoustic pulse
through an array of 60 variable and resonant scatterers periodically distribued
along a waveguide is studied. An arbitrary scattering arrangement is realized
by using the variable length of each resonator cavity. For a periodic
modulation, the structures of forbidden bands of the transmission reproduce the
Hofstadter butterfly. We compare experimental, analytical, and computational
realizations of the Hofstadter butterfly and we show the influence of the
resonances of the scatterers on the structure of the butterfly.",0907.2517v1
2009-08-31,Anomalous diffusion in the resonant quantum kicked rotor,"We study the resonances of the quantum kicked rotor subjected to an
excitation that follows a deterministic time-dependent prescription. For the
primary resonances we find an analytical relation between the long-time
behavior of the standard deviation and the external kick strength. For the
secondary resonances we obtain essentially the same result numerically.
Selecting the time sequence of the kick allows to obtain a variety of
asymptotic wave-function spreadings: super-ballistic, ballistic, sub-ballistic,
diffusive, sub-diffusive and localized.",0908.4596v2
2010-01-19,Isospin breaking effects in the dynamical generation of the X(3872),"We have studied isospin breaking effects in the X(3872) resonance and found a
natural explanation for the branching fraction of the X decaying to $J/\psi$
with two and three pions being close to unit. Within our framework the X(3872)
is a dynamically generated resonance in coupled channels. We also study the
relationship between the couplings of the resonance to the coupled channels
with its wave function, which further helps us to understand the isospin
structure of the resonance.",1001.3254v1
2010-05-20,Dynamical electric dipole theory for quantitatively describing coupled split-ring resonators,"Metallic split-ring resonators possess dominant electric dipoles as well as
considerable magnetic dipoles under proper excitations. Full-wave numerical
approaches are frequently employed to simulate adjacent split-ring resonators,
but simulations cannot explain the underlying physics. An analytical theory
based on a dynamic electric dipole approximation is developed here. Detailed
theory-simulation comparisons demonstrate that this theory can
\textit{quantitatively} describe the interaction strength of coupled
split-ring-resonators under certain circumstances.",1005.3819v1
2010-06-19,Enhancement and Inhibition of Transmission from metal gratings: Engineering the Spectral Response,"We present a systematic analysis of the optical properties of slit arrays in
metal films. An exhaustive investigation of geometrical and dispersive
properties reveals the resonance features of these structures, including the
role of surface waves and their relationship with features in the transmission
spectrum. Although enhanced transmission windows are significantly dominated by
the longitudinal resonances localized inside the slits, the periodicity
introduces transverse resonances that can either enhance or inhibit light
transmission. We thus illustrate the intriguing interaction regime between
longitudinal and transverse resonances, where the two modes hybridize leading
to the formation of a photonic band gap spectrum.",1006.3841v1
2010-08-23,Statistics of resonance states in a weakly open chaotic cavity,"In this letter, we demonstrate that a non-Hermitian Random Matrix description
can account for both spectral and spatial statistics of resonance states in a
weakly open chaotic wave system with continuously distributed losses. More
specifically, the statistics of resonance states in an open 2D chaotic
microwave cavity are investigated by solving the Maxwell equations with lossy
boundaries subject to Ohmic dissipation. We successfully compare the statistics
of its complex-valued resonance states and associated widths with analytical
predictions based on a non-Hermitian effective Hamiltonian model defined by a
finite number of fictitious open channels.",1008.3878v1
2011-08-12,Electrodynamics of the Josephson-Coupled Parallel Plate Resonator,"Eigen oscillations in a superconducting parallel plate resonator with the
Josephson-coupled plates are investigated. While the insulator thickness S
changes from tens of microns down to the decay lengthscale of the
superconducting wavefunction into a dielectric, \xi~1 nm, both the resonant
frequency and Q-factor vary non-monotonically by up to three orders in
magnitude. A crossover between the Swihart waves and Josephson plasmons causes
a global minimum in the resonant frequency and a local maximum in the Q-factor
at S~10\xi.",1108.2697v1
2011-12-15,Electromagnetic cavity tests of Lorentz invariance on Earth and in space,"We present a Michelson-Morley type experiment for testing the isotropy of the
speed of light in vacuum and matter. The experiment compares the resonance
frequency of an actively rotated monolithic optical cryogenic sapphire
resonator against the resonance frequency of a stationary evacuated optical
cavity made of ultra-low-expansion glass. The results yield an upper limit for
the anisotropy of the speed of light in matter (sapphire) of Delta(c)/c < 1 x
10^-16, limited by the frequency stability of the sapphire resonator.",1112.3857v1
2013-06-04,Laser-Machined Ultra-High-Q Microrod Resonators for Nonlinear Optics,"Optical whispering-gallery microresonators are useful tools in
microphotonics, and nonlinear optics at very low threshold powers. Here, we
present details about the fabrication of ultra-high-Q whispering-gallery-mode
resonators made by CO2-laser lathe machining of fused-quartz rods. The
resonators can be fabricated in less than one minute and the obtained optical
quality factors exceed Q = 10^9. Demonstrated resonator diameters are in the
range between 170 {\mu}m and 8 mm (free spectral ranges between 390 GHz and 8
GHz). Using these microresonators, a variety of optical nonlinearities are
observed, including Raman scattering, Brillouin scattering and four-wave
mixing.",1306.0939v1
2015-02-18,Symmetry-assisted resonance transmission of identical particles,"We report novel interference effects in wave packet scattering of identical
particles incident on the same side of a resonant barrier, different from those
observed in Hong-Ou-Mandel experiments. These include significant changes in
the mean number of transmissions and full counting statistics, as well as
""bunching"" and ""anti-bunching"" effects in the all-particles transmission
channel. With several resonances involved, pseudo-resonant driving of the
two-level system in the barrier, may result in sharp enhancement of scattering
probabilities for certain values of temporal delay between the particles.",1502.05325v3
2015-07-29,Resonances in two-electron atoms below the critical charge,"The critical nuclear charge Zc required for a heliumlike atom to have at
least one bound state was recently determined with high accuracy from
variational calculations. Analysis of the wave functions further suggested that
the bound state changes smoothly into a shape resonance as Z crosses the
critical value. Using variational calculations combined with the complex
coordinate rotation method, we study the energy and width of the resonance for
Z \textless{} Zc, thus providing direct evidence of the validity of this
hypothesis. The variation of the resonance width with Z is found to be in good
agreement with a model derived from analysis of the 1/Z perturbation series.",1507.08033v1
2015-08-25,Droplets Acoustics,"Contrary to their capillary resonances (Rayleigh, 1879) and their optical
resonances (Ashkin, 1977), droplets acoustical resonances were rarely
considered. Here we experimentally excite, for the first time, the acoustical
resonances of a droplet that relies on sound instead of capillary waves.
Droplets vibrations at 37 MHz rates and 100 quality factor are optically
excited and interrogated at an optical threshold of 68 microWatt. Our
vibrations span a spectral band that is 1000 times higher when compared with
drops previously-studied capillary vibration.",1508.06628v2
2015-09-18,Fano resonances and band structure of two dimensional photonic structures,"We show that the frequency spectrum of two dimensional photonic crystals is
strongly influenced by Fano resonances which can be excited already in the
linear array of dielectric cylinders. To support this claim, we calculate the
transmission of electromagnetic wave through linear array of dielectric
cylinders and show that frequencies of observed Fano resonances coincides with
position of narrow frequency bands found in the spectra of corresponding
two-dimensional photonic crystals. Split of frequency band or overlap of two
bands, observed in the band structure of photonic structures are also
associated with Fano resonances.",1509.05513v1
2017-07-19,Internal polarization dynamics of vector dissipative-soliton-resonance pulses in normal dispersion fiber lasers,"Investigation of internal polarization dynamics of vector
dissipative-soliton-resonance (DSR) pulses in a mode-locked fiber laser is
presented. Stable vector DSR pulses are experimentally ob- served. Using a
waveplate-analyzer configuration, we find that polarization is not uniform
across a resonant dissipative soliton. Specifically, although the central plane
wave of the resonant dissi- pative soliton acquires nearly a fixed
polarization, the fronts feature polarization states that are different and
spatially varying. This distinct polarizaiton distribution is maintained while
the whole soliton structrue extends with varying gain conditions. Numerical
simulation further confirms the experimental observations.",1707.05939v1
2018-06-28,Electromagnetic Scattering Resonances of Quasi-1D Nanoribbons,"We analyse the resonance conditions of a long and narrow ribbon of finite
length whether it is conductive or dielectric. This is accomplished by using a
full wave approach based on the material independent modes that naturally
discriminates the role of the geometry and of the material. This method
effectively allows the design of the material in such a way to obtain the
desired resonances. Eventually, as an example, we design two quasi-one
dimensional resonators based on a graphene layer and on a silicon thin film.",1806.11088v3
2019-11-29,The enigmatic $Δ(1600)$ resonance,"Our recently proposed model of the $\Delta(1600)$ resonance, in which the
dominant component is a quasi-bound state of the $\Delta(1232)$ and the pion,
is confronted with a similar model of the $N^*(1440)$ resonance as its
counterpart in the P11 partial wave. We stress an essentially different
mechanism responsible for generating the two resonances.",1911.13026v1
2018-02-27,Resonant states in double and triple quantum wells,"The full set of resonant states in double and triple quantum well/barrier
structures is investigated. This includes bound, anti-bound and normal resonant
states which are all eigensolutions of Schrodinger's equation with generalized
outgoing wave boundary conditions. The transformation of resonant states and
their transitions between different subgroups as well as the role of each
subgroup in observables, such as the quantum transmission, is analyzed. The
quantum well potentials are modeled by Dirac delta functions; therefore, as
part of this study, the well-known problem of bound states in delta-like
potentials is also revisited.",1802.09855v2
2018-08-02,Enhanced Attenuation Arising from Lattice Resonances in a Plasma Photonic Crystal,"We describe the experimental verification of lattice resonances in
two-dimensional photonic crystals constructed from an array of gaseous plasma
columns. Enhancements are seen in the extinction of normal incidence transverse
electric electromagnetic waves when the localized surface plasmon modes of the
plasma columns are shifted into the vicinity of the photonic crystal Bragg
resonances. Simulations and experiments are in reasonable agreement and confirm
the appearance of a Fano-like profile with deep and broad extinction bands. The
broadening of the spectra as surface plasmon modes come into coincidence with
Bragg gaps suggest that the Bragg fields couple strongly into the radiating Mie
dipoles to drive enhanced damping of the photonic crystal resonance.",1808.00610v1
2019-02-28,Reflected wavefront manipulation by acoustic metasurface with anisotropic local resonant units,"In this work, we develop the gradient metasurface is constructed of a locally
anisotropic resonant structure, comprising a steel cylinder with an elliptical
rubber coating embedded in epoxy. The deflective angles of rubber ellipses in
the locally anisotropic resonant unit provide a method of controlling the
reflected phase. Phase shifts of the reflected wave can cover the 2pi range.
With an appropriate design of the phase profiles along the acoustic
metasurface, we can achieve anomalous reflection and Bessel beam. The locally
anisotropic resonant units have significant potential for engineering and
manipulating acoustic wavefronts",1902.10862v1
2020-04-20,Supersymmetric quantum mechanics to study the 16.8 MeV resonance state of $^{9}$B,"The study of a high-lying resonant state of $^{9}$B is carried out using
supersymmetric quantum mechanics (SQM). The resulting isospectral potentials
are very deep and narrow and the generated wave functions identify the
resonance at 16.84 MeV with a width of 69 keV. The present work shows that SQM
can be successfully applied for detection of high-lying resonances in unstable
nuclei.",2004.09105v1
2017-06-06,Resonant Transmission in One-Dimensional Quantum Mechanics with Two Independent Point Interactions: Full Parameter Analysis,"We discuss the scattering of a quantum particle by two independent successive
point interactions in one dimension. The parameter space for two point
interactions is given by $U(2)\times U(2)$, which is described by eight real
parameters. We perform an analysis of perfect resonant transmission on the
whole parameter space. By investigating the effects of the two point
interactions on the scattering matrix of plane wave, we find the condition
under which perfect resonant transmission occurs. We also provide the physical
interpretation of the resonance condition.",1706.01595v2
2020-11-29,Resonances of the Laplace operator on homogeneous vector bundles on symmetric spaces of real rank-one,"We study the resonances of the Laplacian acting on the compactly supported
sections of a homogeneous vector bundle over a Riemannian symmetric space of
the non-compact type. The symmetric space is assumed to have rank-one but the
irreducible representation $\tau$ of $K$ defining the vector bundle is
arbitrary. We determine the resonances. Under the additional assumption that
$\tau$ occurs in the spherical principal series, we determine the resonance
representations. They are all irreducible. We find their Langlands parameters,
their wave front sets and determine which of them are unitarizable.",2011.14355v1
2023-11-22,From local to nonlocal high-Q plasmonic metasurfaces,"The physics of bound states in the continuum (BICs) allows to design and
demonstrate optical resonant structures with large values of the quality factor
($Q$-factor) by employing dielectric structures with low losses. However, BIC
is a general wave phenomenon that should be observed in many systems, including
the metal-dielectric structures supporting plasmons where the resonances are
hindered by losses. Here we develop a comprehensive strategy to achieve
high-$Q$ resonances in plasmonic metasurfaces by effectively tailoring the
resonant modes from local and nonlocal regimes.",2311.13452v1
2024-02-06,Terahertz plasmonic resonances in coplanar graphene nanoribbon structures,"We analyze plasmonic oscillations in the coplanar graphene nanoribbon (GNR)
structures induced by the applied terahertz (THz) signals and calculate the GNR
impedance. The plasmonic oscillations in the CNR structures are associated with
the electron and hole inductances and the lateral inter-CNR capacitance. A
relatively low inter-GNR capacitance enables the resonant excitation of the THz
plasmonic oscillations in the CNR structures with long GNRs. The GNR structures
under consideration can be used in different THz devices as the resonant
structures incorporated in THz detectors, THz sources using resonant-tunneling
diodes, photomixers, and surface acoustic wave sensors.",2402.03912v2
1999-11-18,Time-resolved optical observation of spin-wave dynamics,"We have created a nonequilibrium population of antiferromagnetic spin-waves
in Cr2O3, and characterized its dynamics, using frequency- and time-resolved
nonlinear optical spectroscopy of the exciton-magnon transition. We observe a
time-dependent pump-probe line shape, which results from excitation induced
renormalization of the spin-wave band structure. We present a model that
reproduces the basic characteristics of the data, in which we postulate the
optical nonlinearity to be dominated by interactions with long-wavelength
spin-waves, and the dynamics to be due to spin-wave thermalization.",9911294v1
2004-07-16,Interaction and dynamical binding of spin waves or excitons in quantum Hall systems,"Interaction between spin waves (or excitons) moving in the lowest Landau
level is studied using numerical diagonalization. Becuse of complicated
statistics obeyed by these composite particles, their effective interaction is
completely different from the dipole-dipole interaction predicted in the model
of independent (bosonic) waves. In particular, spin waves moving in the same
direction attract one another which leads to their dynamical binding. The
interaction pseudopotentials V_[up,up](k) and V_[up,down](k) for two spin waves
with equal wavevectors k and moving in the same or opposite directions have
been calculated and shown to obey power laws V(k) ~ k^alpha at small k. A high
value of alpha_[up,up]~4 explains the occurrence of linear bands in the spin
excitation spectra of quantum Hall droplets.",0407449v1
2006-06-05,Can the Landau-Lifshitz equation explain the spin-wave instability in ferromagnetic thin films for parallel pumping?,"Spin-wave instability is studied analytically in the case of parallel pumping
for thin films under external field perpendicular to the film plane. It is
examined whether the instability threshold derived from only the
Landau-Lifshitz (LL) equation can explain experimental instability threshold
without using the microscopically-derived spin-wave line width, which is
conventionally used. It is revealed that the butterfly curve cannot be
explained from only the LL equation at least in an analytical way. By contrast,
for the case of perpendicular pumping, the Suhl instability was well explained
from the LL equation. The difference between the two cases comes from the
nonlinear terms describing the relaxation of spin waves. It is suggested how
the nonlinear terms in the LL equation should be related to the spin-wave line
width for parallel pumping.",0606106v1
2008-02-14,Coriolis Effect in Optics: Unified Geometric Phase and Spin-Hall Effect,"We examine the spin-orbit coupling effects that appear when a wave carrying
intrinsic angular momentum interacts with a medium. The Berry phase is shown to
be a manifestation of the Coriolis effect in a non-inertial reference frame
attached to the wave. In the most general case, when both the direction of
propagation and the state of the wave are varied, the phase is given by a
simple expression that unifies the spin redirection Berry phase and the
Pancharatnam--Berry phase. The theory is supported by the experiment
demonstrating the spin-orbit coupling of electromagnetic waves via a surface
plasmon nano-structure. The measurements verify the unified geometric phase,
demonstrated by the observed polarization-dependent shift (spin-Hall effect) of
the waves.",0802.2114v2
2008-04-03,On the coupling between spinning particles and cosmological gravitational waves,"The influence of spin in a system of classical particles on the propagation
of gravitational waves is analyzed in the cosmological context of primordial
thermal equilibrium. On a flat Friedmann-Robertson-Walker metric, when the
precession is neglected, there is no contribution due to the spin to the
distribution function of the particles. Adding a small tensor perturbation to
the background metric, we study if a coupling between gravitational waves and
spin exists that can modify the evolution of the distribution function, leading
to new terms in the anisotropic stress, and then to a new source for
gravitational waves. In the chosen gauge, the final result is that, in the
absence of other kind of perturbations, there is no coupling between spin and
gravitational waves.",0804.0572v1
2008-12-09,Quantized spin waves in the metallic state of magnetoresistive manganites,"High resolution spin waves measurements have been carried out in
ferromagnetic (F) La(1-x)(Sr,Ca)xMnO3 with x(Sr)=0.15, 0.175, 0.2, 0.3 and
x(Ca)=0.3. In all q-directions, close to the zone boundary, the spin wave
spectra consist of several energy levels, with the same values in the metallic
and the x\approx 1/8 ranges. Mainly the intensity varies, jumping from the
lower energy levels determined in the x\approx 1/8 range to the higher energy
ones observed in the metallic state. On the basis of a quantitative agreement
found for x(Sr)=0.15 in a model of ordered 2D clusters, the spin wave anomalies
of the metallic state can be interpreted in terms of quantized spin waves
within the same 2D clusters, embedded in a 3D matrix.",0812.1715v2
2009-02-13,A spin-wave frequency doubler by domain wall oscillation,"We present a new mechanism for spin-wave excitation using a pinned domain
wall which is forced to oscillate at its eigenfrequency and radiates spin
waves. The domain wall acts as a frequency doubler, as the excited spin waves
have twice the frequency of the domain wall oscillation. The investigations
have been carried out using micromagnetic simulations and enable the
determination of the main characteristics of the excited spin-waves such as
frequency, wavelength, and velocity. This behavior is understood by the
oscillation in the perpendicular magnetization which shows two anti-nodes
oscillating out of phase with respect to each other.",0902.2321v1
2009-12-10,Magnonic crystal based forced dominant wavenumber selection in a spin-wave active ring,"Spontaneous excitation of the dominant mode in a spin-wave active ring -- a
self-exciting positive-feedback system incorporating a spin-wave transmission
structure -- occurs at a certain threshold value of external gain. In general,
the wavenumber of the dominant mode is extremely sensitive to the properties
and environment of the spin-wave transmission medium, and is almost impossible
to predict. In this letter, we report on a backward volume magnetostatic
spin-wave active ring system incorporating a magnonic crystal. When mode
enhancement conditions -- readily predicted by a theoretical model -- are
satisfied, the ring geometry permits highly robust and consistent forced
dominant wavenumber selection.",0912.2029v3
2011-09-09,Mode conversion by symmetry breaking of propagating spin waves,"We study spin-wave transport in a microstructured Ni81Fe19 waveguide
exhibiting broken translational symmetry. We observe the conversion of a beam
profile composed of symmetric spin-wave width modes with odd numbers of
antinodes n=1,3,... into a mixed set of symmetric and asymmetric modes. Due to
the spatial homogeneity of the exciting field along the used microstrip
antenna, quantized spin-wave modes with an even number n of antinodes across
the stripe's width cannot be directly excited. We show that a break in
translational symmetry may result in a partial conversion of even spin-wave
waveguide modes",1109.1958v2
2012-08-25,Spin dynamics of possible density wave states in the pseudogap phase of the high temperature superconductors,"In a recent inelastic neutron scattering experiment in the pseudogap state of
the high temperature superconductor $\mathrm{YBa_{2}Cu_{3}O_{6.6}}$ an unusual
`vertical' dispersion of the spin excitations with a large in-plane anisotropy
was observed. In this paper we discuss in detail the spin susceptibility of the
singlet $d$-density wave, the triplet $d$-density wave, as well as the more
common spin density wave orders with hopping anisotropies. From numerical
calculations within the framework of random phase approximation, we find nearly
vertical dispersion relations for spin excitations with anisotropic
incommensurability at low energy $\omega \le 90 meV$, which are reminiscent of
the experiments. At very high energy $\omega \ge 165 meV$, we also find
energy-dependent incommensurability. Although there are some important
difference between the three cases, unpolarized neutron measurements cannot
discriminate between these alternate possibilities; the vertical dispersion,
however, is a distinct feature of all three density wave states in contrast to
the superconducting state, which shows an hour-glass shape dispersion.",1208.5108v1
2013-03-07,Chiral spin-wave edge modes in dipolar magnetic thin films,"Based on a linearized Landau-Lifshitz equation, we show that two-dimensional
periodic allay of ferromagnetic particles coupled with magnetic dipole-dipole
interactions supports chiral spin-wave edge modes, when subjected under the
magnetic field applied perpendicular to the plane. The mode propagates along a
one-dimensional boundary of the system in a unidirectional way and it always
has a chiral dispersion within a band gap for spin-wave volume modes. Contrary
to the well-known Damon-Eshbach surface mode, the sense of the rotation depends
not only on the direction of the field but also on the strength of the field;
its chiral direction is generally determined by the sum of the so-called Chern
integers defined for spin-wave volume modes below the band gap. Using simple
tight-binding descriptions, we explain how the magnetic dipolar interaction
endows spin-wave volume modes with non-zero Chern integers and how their values
will be changed by the field.",1303.1630v3
2013-04-08,Electronic phase separation in iron pnictides,"A mechanism for electronic phase separation in iron pnictides is proposed. It
is based on the competition between commensurate and incommensurate
spin-density-wave phases in a system with an imperfect doping-dependent nesting
of a multi-sheeted Fermi surface. We model the Fermi surface by two elliptical
electron pockets and three circular hole pockets. The interaction between a
charge carrier in a hole band and a carrier in an electron band leads to the
formation of spin-density-wave order. The commensurate spin density wave in the
parent compound transforms to the incommensurate phase when doping is
introduced. We show that, for certain parameter values, the uniform state is
unstable with respect to phase separation. The resulting inhomogeneous state
consists of regions of commensurate and incommensurate spin-density-wave
phases. Our results are in qualitative agreement with recent observations of
incommensurate spin density waves and electronic inhomogeneity in iron
pnictides.",1304.2175v2
2013-10-12,Role of Anion Ordering in the Coexistence of Spin-Density-Wave and Superconductivity in (TMTSF)2ClO4,"Using various transport and magnetotransport probes we study the coexistence
of spin-density wave and superconductor states in (TMTSF)2ClO4 at various
degrees of ClO4 anions ordering. In the two-phase complex state when both
superconductivity and spin-density wave are observed in transport, we find
prehistory effects, enhancement of the superconducting critical field, and
strong spatial anisotropy of the superconducting state. These features are
inconsistent with the conventional model of structural inhomogeneities produced
by anion ordering transition. We reveal instead that superconductor and
spin-density wave regions overlap on the temperature -- dimerization gap V
phase diagram, where V is varied by anion ordering. The effect of anion
ordering on (TMTSF)2ClO4 properties is thus analogous to that of pressure on
(TMTSF)2X (X=PF6 or AsF6), thereby unifying general picture of the coexistence
of superconductivity and spin-density wave in these compounds.",1310.3434v1
2013-11-25,Spin-wave excitation and propagation in microstructured waveguides of yttrium iron garnet (YIG)/Pt bilayers,"We present an experimental study of spin-wave excitation and propagation in
microstructured waveguides patterned from a 100 nm thick yttrium iron garnet
(YIG)/platinum (Pt) bilayer. The life time of the spin waves is found to be
more than an order of magnitude higher than in comparably sized metallic
structures despite the fact that the Pt capping enhances the Gilbert damping.
Utilizing microfocus Brillouin light scattering spectroscopy, we reveal the
spin-wave mode structure for different excitation frequencies. An exponential
spin-wave amplitude decay length of 31 {\mu}m is observed which is a
significant step towards low damping, insulator based micro-magnonics.",1311.6305v1
2014-03-27,Driving spin and charge in quantum wells by surface acoustic waves,"Recent experiments have shown the potential of surface acoustic waves as a
mean for transporting charge and spin in quantum wells. In particular, they
have proven highly effective for the coherent transport of spin-polarized wave
packets, suggesting their potential in spintronics applications. Motivated by
these experimental observations, we have theoretically studied the spin and
charge dynamics in a quantum well under surface acoustic waves. We show that
the dynamics acquires a simple and transparent form in a reference frame
co-moving with the surface acoustic wave. Our results, e.g., the calculated
spin relaxation and precession lengths, are in excellent agreement with recent
experimental observations.",1403.6960v2
2014-04-14,Cavity-enhanced storage in an optical spin-wave memory,"We report on the experimental demonstration of an optical spin-wave memory,
based on the atomic frequency comb (AFC) scheme, where the storage efficiency
is strongly enhanced by an optical cavity. The cavity is of low finesse, but
operated in an impedance matching regime to achieve high absorption in our
intrinsically low-absorbing Eu3+:Y2SiO5 crystal. For storage of optical pulses
as an optical excitation (AFC echoes), we reach efficiencies of 53% and 28% for
2 and 10 microseconds delays, respectively. For a complete AFC spin-wave memory
we reach an efficiency of 12%, including spin-wave dephasing, which is a
12-fold increase with respect to previous results in this material. This result
is an important step towards the goal of making efficient and long-lived
quantum memories based on spin waves, in the context of quantum repeaters and
quantum networks.",1404.3489v1
2014-04-22,Spin-wave-induced correction to the conductivity of ferromagnets,"We calculate the correction to the conductivity of a disordered ferromagnetic
metal due to spin-wave-mediated electron--electron interactions. This
correction is the generalization of the Altshuler-Aronov correction to
spin-wave-mediated interactions. We derive a general expression for the
conductivity correction to lowest order in the spin-wave-mediated interaction
and for the limit that the exchange splitting $\Delta$ is much smaller than the
Fermi energy. For a ""clean"" ferromagnet with $\Delta\tau_{\rm el}/\hbar \gg 1$,
with $\tau_{\rm el}$ the mean time for impurity scattering, we find a
correction $\delta \sigma \propto -T^{5/2}$ at temperatures $T$ above the spin
wave gap. In the opposite, ""dirty"" limit, $\Delta\tau_{\rm el}/\hbar \ll 1$,
the correction is a non-monotonous function of temperature.",1404.5437v1
2014-10-02,Spin wave non-reciprocity and beating in permalloy by time-resolved magneto-optical Kerr effect,"We have studied the propagation characteristics of spin wave modes in a
permalloy stripe by time-resolved magneto-optical Kerr effect techniques. We
observe a beating interference pattern in the time domain under the influence
of an electrical square pulse excitation at the center of the stripe. We also
probe the non-reciprocal behavior of propagating spin waves with a dependence
on the external magnetic field. Spatial dependence studies show that localized
edge mode spin waves have a lower frequency than spin waves in the center of
the stripe, due to the varying magnetization vector across the width of the
stripe.",1410.0441v1
2014-11-04,A micro-sized parametric spin-wave amplifier,"We present the experimental observation of the localized amplification of
externally excited spin waves in a transversely in-plane magnetized
Ni$_{81}$Fe$_{19}$ magnonic waveguide by means of parallel pumping. By
employing microfocussed Brillouin light scattering spectroscopy, we analyze the
dependency of the amplification on the applied pumping power and on the delay
between the input spin-wave packet and the pumping pulse. We show that there
are two different operation regimes: At large pumping powers, the spin-wave
packet needs to enter the amplifier before the pumping is switched on in order
to be amplified while at low powers the spin-wave packet can arrive at any time
during the pumping pulse.",1411.0830v1
2015-02-22,Excitation and detection of propagating spin waves at the single magnon level,"Ferro- and ferrimagnets play host to small-signal, microwave-frequency
magnetic excitations called spin waves, the quanta of which are known as
magnons. Over the last decade, the field of spin-wave dynamics has contributed
much to our understanding of fundamental magnetism. To date, experiments have
focussed overwhelmingly on the study of room-temperature systems within
classical limits. Here we demonstrate, for the first time, the excitation and
detection of propagating spin waves at the single magnon level. Our results
allow us to project that coupling of propagating spin-wave excitations to
quantum circuits is achievable, enabling fundamental quantum-level studies of
magnon systems and potentially opening doors to novel hybrid quantum
measurement and information processing devices.",1502.06263v1
2015-04-10,Influence of magnetic surface anisotropy on spin wave reflection from the edge of ferromagnetic film,"We study propagation of the Gaussian beam of spin waves and its reflection
from the edge of thin yttrium-iron-garnet film with in-plane magnetization
perpendicular to this edge. We have performed micromagnetic simulations
supported by analytical calculations to investigate influence of the surface
magnetic anisotropy present at the film edge on the reflection, especially in
the context of the Goos-Hanchen effect. We have shown the appearance of a
negative lateral shift between reflected and incident spin wave beams' spots.
This shift is particularly sensitive to the surface magnetic anisotropy value
and is a result of the Goos-Hanchen shift which is sensitive to the magnitude
of the anisotropy and of the bending of spin wave beam. We have demonstrated
that the demagnetizing field provide graded increase of the refractive index
for spin waves, which is responsible for the bending.",1504.02668v2
2015-09-17,Antiferromagnetic Spin Wave Field-Effect Transistor,"In a collinear antiferromagnet with easy-axis anisotropy, symmetry dictates
that the spin wave modes must be doubly degenerate. Theses two modes,
distinguished by their opposite polarization and available only in
antiferromagnets, give rise to a novel degree of freedom to encode and process
information. We show that the spin wave polarization can be manipulated by an
electric field induced Dzyaloshinskii-Moriya interaction and magnetic
anisotropy. We propose a prototype spin wave field-effect transistor which
realizes a gate-tunable magnonic analog of the Faraday effect, and demonstrate
its application in THz signal modulation. Our findings open up the exciting
possibility of digital data processing utilizing antiferromagnetic spin waves
and enable the direct projection of optical computing concepts onto the
mesoscopic scale.",1509.05295v3
2015-10-08,"Orbital order, spin waves, and doping effects in the $(π,0)$ SDW state --- comparative study of the three band models for iron pnictides","Aimed at identifying the role of microscopic Hamiltonian parameters on spin
wave excitations, orbital order, and magnetic moments in the $(\pi,0)$ SDW
state, two different three band models for iron pnictides are compared --- one
at two-third filling ($n=4$) and another at half filling $(n=3)$ --- both of
which yield qualitatively correct Fermi surface structure in the paramagnetic
state. Spin wave analysis of the model at $n=4$ shows instability of the SDW
state, which is attributed to weakly developed magnetic moments and weak
magnetic couplings due to overfilling, as inferred from the observed
stabilization of the SDW state and enhancement of magnetic excitation energies
upon hole doping. In contrast, the model at $n=3$ (half filling) yields a
gapped SDW state with well developed magnetic moments and the calculated spin
wave excitations are in excellent agreement with INS experiments. The sign of
the orbital order ($n_{xz} - n_{yz} \approx +0.2$) is also in agreement with
experiments. Both the zone boundary spin wave energies in the F and AF
directions as well as the orbital order are shown to peak near half filling,
highlighting the correlation between orbital order and SDW state stabilization.",1510.02276v1
2015-12-09,Entanglement between Lowly and Highly Lying Atomic Spin Waves,"Establishing a quantum interface between different physical systems is of
special importance for developing the practical versatile quantum networks.
Entanglement between low- and high-lying atomic spin waves is essential for
building up Rydberg-based quantum information engineering, otherwhile be more
helpful to study the dynamics behavior of entanglement under external pertur-
bations. Here, we report on the successful storage of a single photon as a
high-lying atomic spin wave in quantum regime. Via storing a K-vector
entanglement between single photon and lowly lying spin wave, we thereby
experimentally realize the entanglement between low- and high-lying atomic spin
waves in two separated atomic systems. This makes our experiment the primary
demonstration of Rydberg quantum memory of entanglement, making a primary step
toward the construction of a hybrid quantum interface.",1512.02772v3
2016-01-11,Nonlinear effects in the propagation of optically generated magnetostatic volume mode spin waves,"Recent experimental work has demonstrated optical control of spin wave
emission by tuning the shape of the optical pulse (Satoh et al.\ Nature
Photonics, 6, 662 (2012)). We reproduce these results and extend the scope of
the control by investigating nonlinear effects for large amplitude excitations.
We observe an accumulation of spin wave power at the center of the initial
excitation combined with short-wavelength spin waves. These kind of nonlinear
effects have not been observed in earlier work on nonlinearities of spin waves.
Our observations pave the way for the manipulation of magnetic structures at a
smaller scale than the beam focus, for instance in devices with all-optical
control of magnetism.",1601.02511v5
2016-01-27,Quantification of a propagating spin-wave-packet created by an ultrashort laser pulse in a thin film of magnetic metal,"Coherent spin-wave generation by focused ultrashort laser pulse irradiation
was investigated for a permalloy thin film at micrometer scale using an
all-optical space and time-resolved magneto-optical Kerr effect. The spin-wave
packet propagating perpendicular to magnetization direction was clearly
observed, however that propagating parallel to the magnetization direction was
not observed. The propagation length, group velocity, center frequency, and
packet-width of the observed spin-wave packet were evaluated and quantitatively
explained in terms of the propagation of a magneto-static spin-wave driven by
ultrafast change of an out-of-plane demagnetization field induced by the
focused-pulse laser.",1601.07247v1
2016-04-25,Excitation of spin wave modes of a magnetic dot existing in a shifted vortex-state by an out-of-plane oscillating magnetic field,"Excitation of spin wave modes of a vortex-state magnetic dot by an
out-of-plane oscillating magnetic field is studied numerically in the presence
of a static in-plane magnetic field. It is shown, that the application of the
in-plane static field shifts the position of the vortex core and leads to the
separate excitation of different azimuthal dipolar spin waves my perpendicular
oscillating field. It is also shown that the excited dipolar azimuthal spin
waves excite the gyrotropic mode of the vortex core rotation and, depending on
the excitation frequency, cause a significant modification (increase or
decrease) of the apparent dissipation rate of the gyrotropic mode. The last
effect can be explained by the nonlinear parametric interaction between the
gyrotropic mode and the dipolar spin wave modes with different azimuthal
indices.",1604.07161v1
2016-07-26,Transverse azimuthal dephasing of vortex spin wave in a hot atomic gas,"Optical fields with orbital angular momentum (OAM) interact with medium have
many remarkable properties with its unique azimuthal phase, showing many
potential applications in high capacity information processing, high precision
measurement etc. The dephasing mechanics of optical fields with OAM in an
interface between light and matter plays a vital role in many areas of physics.
In this work, we study the transverse azimuthal dephasing of OAM spin wave in a
hot atomic gas via OAM storage. The transverse azimuthal phase difference
between the control and probe beams is mapped onto the spin wave, which
essentially results in dephasing of atomic spin wave. The dephasing of OAM spin
wave can be controlled by the parameters of OAM topological charge and beam
waist. Our results are helpful for studying OAM light interaction with matter,
maybe hold a promise in OAM-based quantum information processing.",1607.07689v1
2016-09-27,Spin-wave dynamics in FeGe helimagnet: studied by small-angle neutron scattering,"We have studied the spin-wave stiffness of the Dzyaloshinskii-Moriya
helimagnet FeGe in a temperature range from 225~K up to $T_C \approx$~278.7~K
by small-angle neutron scattering. The method we have used is based on [S. V.
Grigoriev et al. Phys. Rev. B \textbf{92} 220415(R) (2015)] and was extended
here for the application in polycrystalline samples. We confirm the validity of
the anisotropic spin-wave dispersion for FeGe caused by the
Dzyaloshinskii-Moriya interaction. We have shown that the spin-wave stiffness
$A$ for FeGe helimagnet decreases with a temperature as $A(T) =
194(1-0.7(T/T_C)^{4.2})$ meV\AA$^2$. The finite value of the spin-wave
stiffness $A = 58$ meV\AA$^2$ at $T_C$ classifies the order-disorder phase
transition in FeGe as being the first order one.",1609.08358v1
2018-01-19,Nonabelian magnonics in antiferromagnets,"We present a semiclassical formalism for antiferromagnetic (AFM) magnonics
which promotes the central ingredient of spin wave chirality, encoded in a
quantity called magnonic isospin, to a first-class citizen of the theory. We
use this formalism to unify results of interest from the field under a single
chirality-centric formulation. Our main result is that the isospin is governed
by unitary time evolution, through a Hamiltonian projected down from the full
spin wave dynamics. Because isospin is SU(2)-valued, its dynamics on the Bloch
sphere are precisely rotations - which, in general, do not commute.
Consequently, the induced group of operations on AFM spin waves is nonabelian.
This is a paradigmatic departure from ferromagnetic magnonics, which operates
purely within the abelian group generated by spin wave phase and amplitude. Our
investigation of this nonabelian magnonics in AFM insulators focuses on
studying several simple gate operations, and offering in broad strokes a
program of study for interesting new logic families in antiferromagnetic spin
wave systems",1801.06535v3
2018-01-25,Electrical generation and detection of spin waves in a quantum Hall ferromagnet,"Spin waves are collective excitations of magnetic systems. An attractive
setting for studying long-lived spin-wave physics is the quantum Hall (QH)
ferromagnet, which forms spontaneously in clean two-dimensional electron
systems at low temperature and in a perpendicular magnetic field. We used
out-of-equilibrium occupation of QH edge channels in graphene to excite and
detect spin waves in magnetically ordered QH states. Our experiments provide
direct evidence for long distance spin wave propagation through different
ferromagnetic phases in the N=0 Landau level, as well as across the insulating
canted antiferromagnetic phase. Our results will enable experimental
investigation of the fundamental magnetic properties of these exotic
two-dimensional electron systems.",1801.08534v2
2018-11-01,Population Synthesis of Accreting Neutron Stars Emitting Gravitational Waves,"The fastest-spinning neutron stars in low-mass X-ray binaries, despite having
undergone millions of years of accretion, have been observed to spin well below
the Keplerian break-up frequency. We simulate the spin evolution of synthetic
populations of accreting neutron stars in order to assess whether gravitational
waves can explain this behaviour and provide the distribution of spins that is
observed. We model both persistent and transient accretion and consider two
gravitational-wave-production mechanisms that could be present in these
systems: thermal mountains and unstable $r$-modes. We consider the case of no
gravitational-wave emission and observe that this does not match well with
observation. We find evidence for gravitational waves being able to provide the
observed spin distribution; the most promising mechanisms being a permanent
quadrupole, thermal mountains and unstable $r$-modes. However, based on the
resultant distributions alone it is difficult to distinguish between the
competing mechanisms.",1811.00550v2
2018-11-12,Ultra-narrow spin wave metasurface for focusing application,"In this paper we show that the phase shift of the spin waves can be
controlled in transmission through metasurface represented as an ultra-narrow
non-magnetic spacer separating two ferromagnetic films. We design this
metasurface to present the focusing of spin waves in an Co thin film. For this
purpose we exploit the strength of the interlayer exchange coupling
interactions of RKKY type which allows to control the phase of the transmitted
and reflected spin waves in the wide range of angles [$-\pi/2$;$\pi/2$]. We
combined this phase-shift dependency with the lens equation to demonstrate
numerically the lens for spin waves based on ultra-narrow metasurface.",1811.04613v2
2019-11-25,Snell's law for spin waves at a 90-degree domain wall,"We report experimental observation of the refraction and re ection of
propagating magnetostatic spin waves crossing a 90-degree domain wall (DW) in
terms of time-resolved magneto-optical imaging. Due to the magnetization
rotation across the 90-degree DW, the dispersion relation of magnetostatic spin
waves rotates by 90 degrees, which results in the change in the propagation
dynamics of spin waves in both sides of the DW. We observe the refraction and
re ection of magnetosatatc spin waves at the 90-degree DW, and reveal their
characteristics, such as negative refraction. The incident-angle dependence of
the refraction angle is explained by the wavenumber conservation along the DW,
same as the case of Snell's law for light.",1911.10659v1
2017-05-08,Deviation and precession effects in the field of a weak gravitational wave,"Deviation and precession effects of a bunch of spinning particles in the
field of a weak gravitational plane wave are studied according to the
Mathisson-Papapetrou-Dixon (MPD) model. Before the passage of the wave the
particles are at rest with associated spin vector aligned along a given
direction with constant magnitude. The interaction with the gravitational wave
causes the particles to keep moving on the 2-plane orthogonal to the direction
of propagation of the wave, with the transverse spin vector undergoing
oscillations around the initial orientation. The transport equations for both
the deviation vector an spin vector between two neighboring world lines of such
a congruence are then solved by a suitable extension of the MPD model off the
spinning particle's world line. In order obtain measurable physical quantities
a ""laboratory"" has been set up by constructing a Fermi coordinate system
attached to a reference world line. The {\it exact} transformation between TT
coordinates and Fermi coordinates is derived too.",1705.02794v1
2017-05-25,Spin-wave spectroscopy on Dzyaloshinskii-Moriya interaction in room-temperature chiral magnets hosting skyrmions,"Propagation character of spin wave was investigated for chiral magnets FeGe
and Co-Zn-Mn alloys, which can host magnetic skyrmions near room temperature.
On the basis of the frequency shift between counter-propagating spin waves, the
magnitude and sign of Dzyaloshinskii-Moriya (DM) interaction were directly
evaluated. The obtained magnetic parameters quantitatively account for the size
and helicity of skyrmions as well as their materials variation, proving that
the DM interaction plays a decisive role in the skyrmion formation in this
class of room-temperature chiral magnets. The propagating spin-wave
spectroscopy can thus be an efficient tool to study DM interaction in bulk
single-phase compounds. Our results also demonstrate a function of spin-wave
diode based on chiral crystal structures at room temperature.",1705.09001v1
2018-07-27,Optimization of Multi-Frequency Magnonic Waveguides with Enhanced Group Velocities by Exchange Coupled Ferrimagnet/Ferromagnet Bilayers,"We report broadband spectroscopy and numerical analysis by which we explore
propagating spin waves in a magnetic bilayer consisting of a 23 nm thick
permalloy film deposited on 130 nm thick $Y_{3}Fe_{5}O_{12}$. In the bilayer,
we observe a characteristic mode that exhibits a considerably larger group
velocity at small in-plane magnetic field than both the magnetostatic and
perpendicular standing spin waves. Using the finite element method, we confirm
the observations by simulating the mode profiles and dispersion relations. They
illustrate the hybridization of spin wave modes due to exchange coupling at the
interface. The high-speed propagating mode found in the bilayer can be utilized
to configure multi-frequency spin wave channels enhancing the performance of
spin wave based logic devices.",1807.10508v2
2018-02-12,Dynamics of a magnetic skyrmionium driven by spin waves,"The magnetic skyrmionium is a skyrmion-like structure but carries a zero net
skyrmion number, which can be used as a building block for non-volatile
information processing devices. Here, we study the dynamics of a magnetic
skyrmionium driven by propagating spin waves. It is found that the skyrmionium
can be effectively driven into motion by spin waves showing tiny skyrmion Hall
effect, of which the mobility is much better than that of the skyrmion at the
same condition. We also show that the skyrmionium mobility depends on the
nanotrack width and damping coefficient, and can be controlled by an external
out-of-plane magnetic field. Besides, we demonstrate the skyrmionium motion
driven by spin waves is inertial. Our results indicate that the skyrmionium is
a promising building block for building spin-wave spintronic devices.",1802.03868v2
2016-12-07,Non-volatile spin wave majority gate at the nanoscale,"A spin wave majority fork-like structure with feature size of 40\,nm, is
presented and investigated, through micromagnetic simulations. The structure
consists of three merging out-of-plane magnetization spin wave buses and four
magneto-electric cells serving as three inputs and an output. The information
of the logic signals is encoded in the phase of the transmitted spin waves and
subsequently stored as direction of magnetization of the magneto-electric cells
upon detection. The minimum dimensions of the structure that produce an
operational majority gate are identified. For all input combinations, the
detection scheme employed manages to capture the majority phase result of the
spin wave interference and ignore all reflection effects induced by the
geometry of the structure.",1612.02170v1
2017-06-10,Spin wave nonreciprocity and magnonic band structure in thin permalloy film induced by dynamical coupling with an array of Ni stripes,"An efficient way for the control of spin wave propagation in a magnetic
medium is the use of periodic patterns known as magnonic crystals (MCs).
However, the fabrication of MCs especially bi-components, with periodicity on
nanoscale, is a challenging task due to the requirement for sharp interfaces.
An alternative method to circumvent this problem is to use homogeneous
ferromagnetic film with modified periodically surrounding. The structure is
also suitable for exploiting nonreciprocal properties of the surface spin
waves. In this work, we demonstrate that the magnonic band structure forms in
thin permalloy film due to dynamical magnetostatic coupling with Ni stripes
near its surface. We show, that the band gap width can be systematically tuned
by the changing interlayer thickness between film and stripes. We show also the
effect of nonreciprocity, which is seen at the band gap edge shifted from the
Brillouin zone boundary and also in nonreciprocal interaction of propagating
spin waves in Py film with the standing spin waves in Ni stripes. Our findings
open possibility for further investigation and exploitation of the
nonreciprocity and band structure in magnonic devices.",1706.03202v1
2020-09-07,Field-theory spin and momentum in water waves,"Spin is a fundamental yet nontrivial intrinsic angular-momentum property of
quantum particles or fields, which appears within relativistic field theory.
The spin density in wave fields is described by the theoretical
Belinfante-Rosenfeld construction based on the difference between the canonical
and kinetic momentum densities. These quantities are usually considered as
abstract and non-observable per se. Here, we demonstrate, both theoretically
and experimentally, that the Belinfante-Rosenfeld construction naturally arises
in gravity (water surface) waves. There, the canonical momentum is associated
with the generalized Stokes-drift phenomenon, while the spin is generated by
subwavelength circular motion of water particles. Thus, we directly observe
these fundamental field-theory properties as microscopic mechanical properties
of a classical wave system. Our findings shed light onto the nature of spin and
momentum in wave fields, demonstrate the universality of relativistic
field-theory concepts, and offer a new platform for their studies.",2009.03245v4
2020-11-02,Simulating Spin Waves in Entropy Stabilized Oxides,"The entropy stabilized oxide
Mg$_{0.2}$Co$_{0.2}$Ni$_{0.2}$Cu$_{0.2}$Zn$_{0.2}$O exhibits antiferromagnetic
order and magnetic excitations, as revealed by recent neutron scattering
experiments. This observation raises the question of the nature of spin wave
excitations in such disordered systems. Here, we investigate theoretically the
magnetic ground state and the spin-wave excitations using linear spin-wave
theory in combination with the supercell approximation to take into account the
extreme disorder in this magnetic system. We find that the experimentally
observed antiferromagnetic structure can be stabilized by a rhombohedral
distortion together with large second nearest neighbor interactions. Our
calculations show that the spin-wave spectrum consists of a well-defined
low-energy coherent spectrum in the background of an incoherent continuum that
extends to higher energies.",2011.01288v1
2021-04-23,Spin-wave frequency combs,"We experimentally demonstrate the generation of spin-wave frequency combs
based on the nonlinear interaction of propagating spin waves in a
microstructured waveguide. By means of time and space-resolved Brillouin light
scattering spectroscopy, we show that the simultaneous excitation of spin waves
with different frequencies leads to a cascade of four-magnon scattering events
which ultimately results in well-defined frequency combs. Their spectral weight
can be tuned by the choice of amplitude and frequency of the input signals.
Furthermore, we introduce a model for stimulated four-magnon scattering which
describes the formation of spin-wave frequency combs in the frequency and time
domain.",2104.11491v2
2021-10-21,Generation of perfect-cavity-enhanced atom-photon entanglement with a millisecond lifetime via a spatially-multiplexed cavity,"A qubit memory is the building block for quantum information. Cavity-enhanced
spin-wave-photon entanglement has been achieved by applying dual-control modes.
However, owing to cross readouts between the modes, the qubit retrieval
efficiency is about one quarter lower than that for a single spin-wave mode at
all storage times. Here, we overcome cross readouts using a multiplexed ring
cavity. The cavity is embedded with a polarization interferometer, and we
create a write-out photonic qubit entangled with a magnetic-field-insensitive
spin-wave qubit by applying a single-mode write-laser beam to cold atoms. The
spin-wave qubit is retrieved with a single-mode read-laser beam, and the
quarter retrieval-efficiency loss is avoided at all storage times. Our
experiment demonstrates 50% intrinsic retrieval efficiency for 540 microsecond
storage time, which is 13.5 times longer than the best reported result.
Importantly, our multiplexed-cavity scheme paves one road to generate
perfect-cavity-enhanced and large-scale multiplexed spin-wave-photon
entanglement with a long lifetime.",2110.10971v1
2019-01-30,Propagation of Spin Waves Through an Interface Between Ferromagnetic and Antiferromagnetic Materials,"Boundary conditions for order parameters at an interface between
ferromagnetic (FM) and two-sublattice antiferromagnetic (AFM) materials were
obtained in the continuous medium approximation similarly to the approach which
allows one to take into account the finite thickness of the FM/FM interface,
which is much less than spin wave length. Three order parameters are considered
inside an interface of finite thickness with the magnetization
$\mathbf{\text{M}}$ of FM, magnetizations of both sublattices
$\mathbf{\text{M}}_{1}$ and $\mathbf{\text{M}}_{2}$ of AFM. The uniform and
non-uniform exchange between all order parameters are taken into account to the
interface energy. Using these boundary conditions, the excitation of a surface
evanescent spin wave is considered in AFM when the spin wave in FM falls onto
this interface. The coefficients and the phases of transmission and reflection
of spin wave through the FM/AFM interface are derived.",1901.10988v1
2019-04-01,Inelastic spin-wave scattering by Bloch domain wall flexure oscillations,"The calculations of the inelastic spin wave scattering by flexure vibrations
of the Bloch domain wall (Winters magnons) in thin magnetic films are
presented. The approach is based on the interaction of the propagating spin
waves with the dynamical emergent electromagnetic field generated by the moving
inhomogeneous magnetization texture (domain wall). The probability of the spin
wave scattering for the Winters magnon emission and absorption processes
essentially rises with the spin wave scattering angle increase up to 900. The
angular dependence of the scattering probability is essentially stronger for
the magnon absorption processes that allow distinguishing these elementary
emission/absorption processes experimentally.",1904.00596v1
2019-04-25,Spin-wave propagation in metallic CoFe films determined by microfocused frequency-resolved magneto-optic Kerr effect,"We investigated the magnetization dynamics of a patterned
Co$_{25}$Fe$_{75}$-based heterostructure with a novel optical measurement
technique that we call microfocused frequency-resolved magneto optic Kerr
effect ($\mu$FR-MOKE). We measured the magnetic field dependence of the
dynamical spin-wave susceptibility and recorded a spatial map of the spin-waves
excited by a microwave antenna. We compare these results to those obtained on
the same sample with the established microfocused Brillouin light scattering
technique. With both techniques, we find a spin-wave propagation length of
5.6$\mu$m at 10GHz. Furthermore, we measured the dispersion of the wavevector
and the spin-wave propagation length as a function of the external magnetic
field. These results are in good agreement with existing literature and with
the employed Kalinkos-Slavin model.",1904.11273v1
2019-07-10,Spin-Wave Multiplexed Atom-Cavity Electrodynamics,"We introduce multiplexed atom-cavity quantum electrodynamics with an atomic
ensemble coupled to a single optical cavity mode. Multiple Raman dressing beams
establish cavity-coupled spin-wave excitations with distinctive spatial
profiles. Experimentally, we demonstrate the concept by observing spin-wave
vacuum Rabi splittings, selective superradiance, and interference in the
cavity-mediated interactions of two spin waves. We highlight that the current
experimental configuration allows rapid, interchangeable cavity-coupling to 4
profiles with an overlap parameter of less than 10%, enough to demonstrate, for
example, a quantum repeater network simulation in the cavity. With further
improvements to the optical multiplexing setup, we infer the ability to access
more than $10^3$ independent spin-wave profiles.",1907.04921v2
2019-08-09,Sustained coherent spin wave emission using frequency combs,"We demonstrate sustained coherent emission of spin waves in NiFe films using
rapid demagnetization from high repetition rate femtosecond laser pulse trains.
As the pulse separation is shorter than the magnon decay time, magnons having a
frequency equal to a multiple of the 1 GHz repetition-rate are coherently
amplified. Using scanning micro-Brillouin Light Scattering (BLS) we observe
this coherent amplification as strong peaks spaced 1 GHz apart. The BLS counts
vs. laser power exhibit a stronger than parabolic dependence consistent with
counts being proportional to the square of the magnetodynamic amplitude, and
the demagnetization pulse strength being described by a Bloch law. Spatial spin
wave mapping demonstrates how both localized and propagating spin waves can be
excited, and how the propagation direction can be directly controlled. Our
results demonstrate the versatility of BLS spectroscopy for rapid
demagnetization studies and enable a new platform for photo-magnonics where
sustained coherent spin waves can be utilized.",1908.03388v2
2019-10-16,Spin-Wave frequency division multiplexing in an yttrium iron garnet microstripe magnetized by inhomogeneous field,"Spin waves are promising candidates for information processing and
transmission in a broad frequency range. In the realization of magnonic
devices, the frequency depended division of the spin wave frequencies is a
critical function for parallel information processing. In this work, we
demonstrate a proof-of-concept spin-wave frequency division multiplexing method
by magnetizing a homogenous magnetic microstripe with an inhomogeneous field.
The symmetry breaking additional field is introduced by a permalloy stripe
simply placed in lateral proximity to the waveguide. Spin waves with different
frequencies can propagate independently, simultaneously and separately in space
along the shared waveguide. This work brings new potentials for parallel
information transmission and processing in magnonics.",1910.07136v1
2020-05-21,Effect of Dzyaloshinskii-Moriya interaction on magnetic vortex switching driven by radial spin waves,"We theoretically investigate the radial-spin-wave induced magnetic vortex
switching in the presence of Dzyaloshinskii-Moriya interaction (DMI). From
micromagnetic simulations, we observe a circular-to-radial vortex phase
transition by increasing the DMI strength. The radial spin-wave excitation
spectrum for each magnetization configuration is analyzed, showing that the
frequency of spin-wave mode with a given radial node number monotonically
increases (decreases) with the DMI parameter of the radial (circular) vortex.
Interestingly, we find that the DMI can significantly facilitate the polarity
switching of the circular vortex driven by radial spin waves. Our work provides
a new insight into the DMI effect on the vortex dynamics and is helpful for
designing fast all-magnonic memory devices.",2005.10440v1
2020-06-28,Geometrical interpretation of the wave-pilot theory and manifestation of the spinor fields,"Using the hydrodynamical formalism of quantum mechanics for a Schrodinger
spinning particle, developed by T. Takabayashi, J. P. Vigier and followers,
that involves vortical flows, we propose the new geometrical interpretation of
the wave-pilot theory. The spinor wave in this interpretation represents an
objectively real field and the evolution of a material particle controlled by
the wave is a manifestation of the geometry of space. We assume this field to
have a geometrical nature, basing on the idea that the intrinsic angular
momentum, the spin, modifies the geometry of the space, which becomes a
manifold, that is represented as a vector bundle with a base formed by the
translational coordinates and time, and the fiber of the bundle, specified at
each point by the field of an tetrad $e^a_{\mu}$, forms from the bilinear
combinations of spinor wave function. It was shown, that the spin vector
rotates following the geodesic of the space with torsion and the particle moves
according to the geometrized guidance equation. This fact explains the
self-action of the spinning particle. We show that the curvature and torsion of
the spin vector line is determined by the space torsion of the absolute
parallelism geometry.",2006.15709v1
2020-10-09,Skew scattering and side jump of spin wave across magnetic texture,"Spin wave and magnetic texture are two elementary excitations in magnetic
systems, and their interaction leads to rich magnetic phenomena. By describing
the spin wave and the magnetic texture using their own collective coordinates,
we find that they interact as classical particles traveling in mutual
electromagnetic fields. Based on this unified collective coordinate model, we
find that both skew scattering and side jump may occur as spin wave passing
through magnetic textures. The skew scattering is associated with the magnetic
topology of the texture, while the side jump is correlated to the total
magnetization of the texture. We illustrate the concepts of skew scattering and
side jump by investigating the spin wave trajectories across the topological
magnetic Skyrmion and the topologically trivial magnetic bubble respectively.",2010.04626v1
2020-12-17,Geometric magnonics with chiral magnetic domain walls,"Spin wave, the collective excitation of magnetic order, is one of the
fundamental angular momentum carriers in magnetic systems. Understanding the
spin wave propagation in magnetic textures lies in the heart of developing pure
magnetic information processing schemes. Here we show that the spin wave
propagation across a chiral domain wall follows simple geometric trajectories,
similar to the geometric optics. And the geometric behaviors are qualitatively
different in normally magnetized film and tangentially magnetized film. We
identify the lateral shift, refraction, and total reflection of spin wave
across a ferromagnetic domain wall. Moreover, these geometric scattering
phenomena become polarization-dependent in antiferromagnets, indicating the
emergence of spin wave birefringence inside antiferromagnetic domain wall.",2012.09420v1
2021-03-05,Local heat emission due to unidirectional spin-wave heat conveyer effect observed by lock-in thermography,"Lock-in thermography measurements were performed to reveal heat source
distribution induced by the unidirectional spin-wave heat conveyer effect
(USHCE) of magnetostatic surface spin waves. When the magnetostatic surface
spin waves are excited in an yttrium iron garnet slab, the lock-in thermography
images show spatially biased sharp and complicated heating patterns, indicating
the importance of edge spin-wave dynamics for USHCE. The accessibility to the
local heat emission properties allows us to clarify a capability of remote
heating realized by USHCE; it can transfer energy for heating even through a
macro-scale air gap between two magnetic materials owing to the long-range
dipole-dipole coupling.",2103.03694v1
2021-05-06,Short spin waves detection by means of the magneto-optical intensity effect,"It is proposed a novel method of the spectrally selective detection of the
short spin waves (or magnons) by means of the transverse magneto-optical (MO)
intensity effect in transmission in the magnetoplasmonic nanostructure. The
method is based on the analysis of the MO effect spectrum versus the modulation
of the sample magnetization (i.e. spin wave) and related spatial symmetry
breaking in the magnetic layer. The spatial symmetry breaking leads to the
appearance of MO effect modulation at the normal incidence of light in the
spectral range of the optical states (SPP and waveguide modes) and the breaking
of the antisymmetry of the effect with respect to the sign of the incidence
angle of light. Besides it is revealed that the magnitude of the MO effect
varies with respect to the phase shift between the spin wave and the plasmonic
grating as a harmonic function with a period equal to the magnon wavelength.
All these facts allow to detect the spin waves of the certain wavelength
propagating in the nanostructure by measuring of the MO effect in the
nanostructure.",2105.02539v1
2021-06-21,First experimental demonstration of a scalable linear majority gate based on spin waves,"We report on the first experimental demonstration of majority logic operation
using spin waves in a scaled device with an in-line input and output layout.
The device operation is based on the interference of spin waves generated and
detected by inductive antennas in an all-electrical microwave circuit. We
demonstrate the full truth table of a majority logic function with the ability
to distinguish between strong and weak majority, as well as an inverted
majority function by adjusting the operation frequency. Circuit performance
projections predict low energy consumption of spin wave based compared to CMOS
for large arithmetic circuits.",2106.11192v1
2021-09-30,Linear and continuous variable spin-wave processing using a cavity-coupled atomic ensemble,"Spin-wave excitations in ensembles of atoms are gaining attention as a
quantum information resource. However, current techniques with atomic spin
waves do not achieve universal quantum information processing. We conduct a
theoretical analysis of methods to create a high-capacity universal quantum
processor and network node using an ensemble of laser-cooled atoms, trapped in
a one-dimensional periodic potential and coupled to a ring cavity. We describe
how to establish linear quantum processing using a lambda-scheme in a
rubidium-atom system, calculate the expected experimental operational
fidelities. Second, we derive an efficient method to achieve linear
controllability with a single ensemble of atoms, rather than two-ensembles as
proposed in [K. C. Cox et al. Spin-Wave Quantum Computing with Atoms in a
Single-Mode Cavity, preprint 2021]. Finally, we propose to use the spin-wave
processor for continuous-variable quantum information processing and present a
scheme to generate large dual-rail cluster states useful for deterministic
computing.",2109.15246v1
2021-11-30,Nonreciprocity of spin waves in a double layer ferromagnet with Dzyaloshinskii-Moriya interactions,"In this paper, boundary conditions for Landau-Lifshitz equations at the
interface between two ferromagnets with different Dzyaloshinskii-Moriya
interactions are derived. We calculated and verified the analytical expression
for the energy flux density continuity for the spin-wave propagation through
the interface between two ferromagnets with/without Dzyaloshinskii-Moriya
interactions considering the boundary conditions mentioned. Analytical
expressions for reflection, transmission coefficients and the nonreciprocity
factor are calculated in the case of spin-wave propagation through a double
layer ferromagnet with/without Dzyaloshinskii-Moriya interactions in the
first/second layer. Two principally different types of nonreciprocity effects
for spin waves are revealed in such a double layer system. The material
parameters of a double layer ferromagnet with/without Dzyaloshinskii-Moriya
interactions in the first/second layer are found for which the extremely high
nonreciprocity factor (>10) is expected according to the results of
calculations. The results of the paper deepen the knowledge about the spin-wave
propagation control in magnonic devices.",2111.15244v1
2022-03-08,Interplay between nonlinear spectral shift and nonlinear damping of spin waves in ultrathin YIG waveguides,"We use the phase-resolved imaging to directly study the nonlinear
modification of the wavelength of spin waves propagating in 100-nm thick,
in-plane magnetized YIG waveguides. We show that, by using moderate microwave
powers, one can realize spin waves with large amplitudes corresponding to
precession angles in excess of 10 degrees and nonlinear wavelength variation of
up to 18 percent in this system. We also find that, at large precession angles,
the propagation of spin waves is strongly affected by the onset of nonlinear
damping, which results in a strong spatial dependence of the wavelength. This
effect leads to a spatially dependent controllability of the wavelength by the
microwave power. Furthermore, it leads to the saturation of nonlinear spectral
shift's effects several micrometers away from the excitation point. These
findings are important for the development of nonlinear, integrated spin-wave
signal processing devices and can be used to optimize their characteristics.",2203.04018v1
2022-04-14,Micro magnet location using spin waves,"In this work, we present experimental data demonstrating the feasibility of
magnetic object location using spin waves. The test structure includes a
Y$_3$Fe$_2$(FeO$_4$)$_3$) (YIG) film with four micro-antennas placed on the
edges. A constant in-plane bias magnetic field is provided by NdFeB permanent
magnet. Two antennas are used for spin wave excitation while the other two are
used for the inductive voltage measurement. There are nine selected places for
the magnet on the film. The magnet was subsequently placed in all nine
positions and spin wave transmission and reflection were measured. The obtained
experimental data show the difference in the output signal amplitude depending
on the magnet position. All nine locations can be identified by the frequency
and the amplitude of the absolute minimum in the output power. All experiments
are accomplished at room temperature. Potentially, spin waves can be utilized
for remote magnetic bit read-out. The disadvantages and physical constraints of
this approach are also discussed.",2204.07238v1
2022-07-10,Semimetallic spin-density wave state in iron pnictides,"We examine the existence of semimetallic spin-density wave states in iron
pnictides. In the experimentally observed metallic spin-density wave state, the
symmetry-protected Dirac cones are located away from the Fermi surface giving
rise to tiny pockets and there are also additional Fermi pockets such as one
around $\Gamma$. We find that the location of a pair of Dirac points with
respect to the Fermi surface exhibits significant sensitivity to the orbital
splitting between the $d_{xz}$ and $d_{yz}$ orbitals. Besides, in the presence
of orbital splitting, the Fermi pockets not associated with the Dirac cones,
can be suppressed so that a semimetallic spin-density wave state can be
realized. We explain these finding in terms of difference in the slopes and
orbital contents of the bands which form the Dirac cone, and obtain the
necessary conditions dependent on these two and other parameters for the
coexisting Dirac semimetallic and spin-density wave states. Additionally, the
topologically protected edge states are studied in the ribbon geometry when the
same are oriented either along $x$ or $y$ axes.",2207.04365v1
2022-11-23,Anatomy of spin wave driven magnetic texture motion via magnonic torques,"The interplay between spin wave and magnetic texture represents the
information exchange between the fast and slow dynamical parts of magnetic
systems. Here we formulate a set of magnonic torques acting on background
magnetic texture, by extracting time-invariant information from the fast
precessing spin waves. Under the frame of magnonic torques, we use theoretical
formulations and micromagnetic simulations to investigate the spin wave driven
domain wall motion in two typical symmetry-breaking situations: the rotational
symmetry broken by the Dzyaloshinkii-Moriya interaction, and the translational
symmetry broken by magnetic damping. The torque-based microscopic analyses
provide compact yet quantitative tools to reinterpret the magnetic texture
dynamics induced by spin wave, beyond the conventional framework of global
momentum conservation.",2211.12958v1
2023-02-25,Magnonic Hall Effect and Magnonic Holography of Hopfions,"Hopfions are localized and topologically non-trivial magnetic configurations
that have received considerable attention in recent years. Through a
micromagnetic approach, we analyze the scattering of spin waves by magnetic
hopfions. We show that the spin waves experience an emergent electromagnetic
field related to the topological properties of the hopfion. We find that spin
waves propagating along the hopfion symmetry axis are deflected by the magnetic
texture, which acts as a convergent or divergent lens, depending on the spin
wave propagation direction. The effect differs for spin waves propagating along
the plane perpendicular to the symmetry axis. In the last case, they respond
with a skew scattering and a closely related Aharonov-Bohm effect. This allows
probing the existence of a magnetic hopfion by magnonic holography.",2302.13190v1
2023-04-05,High-energy spin waves in the spin-1 square-lattice antiferromagnet La$_2$NiO$_4$,"Inelastic neutron scattering is used to study the magnetic excitations of the
$S=1$ square-lattice antiferromagnet La$_2$NiO$_4$. We find that the spin waves
cannot be described by a simple classical (harmonic) Heisenberg model with only
nearest-neighbor interactions. The spin-wave dispersion measured along the
antiferromagnetic Brillouin-zone boundary shows a minimum energy at the
$(1/2,0)$ position as is observed in some $S=1/2$ square-lattice
antiferromagnets. Thus, our results suggest that the quantum dispersion
renormalization effects or longer-range exchange interactions observed in
cuprates and other $S=1/2$ square-lattice antiferromagnets are also present in
La$_2$NiO$_4$. We also find that the overall intensity of the spin-wave
excitations is suppressed relative to linear spin-wave theory indicating that
covalency is important. Two-magnon scattering is also observed.",2304.02546v2
2023-07-04,Probing general relativistic spin-orbit coupling with gravitational waves from hierarchical triple systems,"Wave packets propagating in inhomogeneous media experience a coupling between
internal and external degrees of freedom and, as a consequence, follow
spin-dependent trajectories. These are known as spin Hall effects, which are
well known in optics and condensed matter physics. Similarly, the gravitational
spin Hall effect is expected to affect the propagation of gravitational waves
on curved spacetimes. In this general-relativistic setup, the curvature of
spacetime acts as impurities in a semiconductor or inhomogeneities in an
optical medium, leading to a frequency- and polarization-dependent propagation
of wave packets. In this letter, we study this effect for strong-field lensed
gravitational waves generated in hierarchical triple black hole systems in
which a stellar-mass binary merges near a more massive black hole. We calculate
how the gravitational spin Hall effect modifies the gravitational waveforms and
show its potential for experimental observation. If detected, these effects
will bear profound implications for astrophysics and tests of general
relativity.",2307.01903v1
2023-08-28,Spin wave mode conversion in an in-plane magnetized microscale T-shaped YIG magnonic splitter,"As one of the fundamental magnonic devices, a magnonic splitter device has
been proposed and spin wave propagation in this device has been studied
numerically and experimentally. In the present work, we fabricated a T-shaped
magnonic splitter with 6 $\mu$m-wide three arms using a 100 nm-thick yttrium
iron garnet film and, using time-resolved magneto-optic Kerr microscopy,
observed that spin waves split into both, the vertical and the horizontal
direction at the junction. Analyzing the results, we found that spin wave modes
are converted into another during the splitting process and the splitting
efficiency is dominantly dependent on the 1st order of incoming spin waves.",2308.14327v1
2001-06-20,Measurements of the Gravity Waves Velocity,"Some results are presented of the Earth's microseismic background. It is
assumed that background peaks should correspond to the resonance gravity-wave
exchange in the system of two gravity-connected bodies. The microseismic
spectrum is compared with the distribution of gravity potential of the nearest
stars. A close peak-to-peak correspondence is found. This correspondence and
resonance condition lead to an evaluation of the gravity-wave velocity. The
resulting value is nine orders of magnitude more than the velocity of light.
Some consequences of such result are discussed.",0106350v1
2007-03-13,Spectral line width decrease in the solar corona: resonant energy conversion from Alfv{é}n to acoustic waves,"Observations reveal an increase with height of the line width of several
coronal spectral lines probably caused by outwardly propagating Alfv{\'e}n
waves. However, the spectral line width sometimes shows a sudden decrease at a
height 0.1-0.2 R, where the ratio of sound to Alfven speeds may approach unity.
Qualitative analysis shows that the resonant energy conversion from Alfven to
acoustic waves near the region of the corona where the plasma $\beta$
approaches unity may explain the observed spectral line width reduction.",0703297v1
2003-11-04,Feshbach resonance induced shock waves in Bose-Einstein condensates,"We propose a method for generating shock waves in Bose-Einstein condensates
by rapidly increasing the value of the nonlinear coefficient using Feshbach
resonances. We show that in a cigar-shaped condensate there exist primary
(transverse) and secondary (longitudinal) shock waves. We analyze how the
shocks are generated in multidimensional scenarios and describe the
phenomenology associated with the phenomenon.",0311076v1
1996-02-12,Influence of geomagnetic perturbation on resonant gravitational wave detector,"The level of background signals in modern cryogenic resonant mass
gravitational wave antenna is discussed caused by (a) the geomagnetic field
pulsations and (b) an atmosferic of very low frequency band, generated by a
lightning flash. The analysis of our results show that the signals of this
origin will generally exceed the signals from the gravitational wave sources.
To suppress these artifacts in such gravitational antenna, it is necessary to
use the magnetometer included as anti-coincidence protection and a system of
magnetic screens.",9603016v1
2004-06-25,Partial wave analysis of pbar-p to Lambdabar-Lambda,"A partial wave analysis of PS185 data for pbar-p to Lambda-bar Lambda is
presented. A 3S1 cusp is identified in the inverse process Lambda-bar Lambda to
pbar-p at threshold using detailed balance. Partial wave amplitudes for pbar-p
3P0, 3F3, 3D3 and 3G3 exhibit a behaviour very similar to resonances observed
in Crystal Barrel data. With this identification, the pbar-p to Lambda-bar
Lambda data then provide evidence for a new I = 0, J^{PC} = 1^{--} resonance
with mass M = 2290 +- 20 MeV, Gamma = 275 +- 35 MeV, coupling to both 3S1 and
3D1.",0406292v1
1997-06-24,Variational Perturbation Approach to Resonance-State Wave Functions,"The variational perturbation theory for wave functions, which has been shown
to work well for bound states of the anharmonic oscillator, is applied to
resonance states of the anharmonic oscillator with negative coupling constant.
We obtain uniformly accurate wave functions starting from the bound states.",9706162v2
2005-09-21,Exact solutions of the 3-wave resonant interaction equation,"The Darboux--Dressing Transformations are applied to the Lax pair associated
to the system of nonlinear equations describing the resonant interaction of
three waves in 1+1 dimensions. We display explicit solutions featuring
localized waves whose profile vanishes at the spacial boundary plus and minus
infinity, and which are not pure soliton solutions. These solutions depend on
an arbitrary function and allow to deal with collisions of waves with various
profiles.",0509038v1
2000-01-20,From bound states to resonances: analytic continuation of the wave function,"Single-particle resonance parameters and wave functions in spherical and
deformed nuclei are determined through analytic continuation in the potential
strength. In this method, the analyticity of the eigenvalues and eigenfunctions
of the Schroedinger equation with respect to the coupling strength is exploited
to analytically continue the bound-state solutions into the positive-energy
region by means of Pade' approximants of the second kind. The method is here
applied to single-particle wave functions of the $^{154}Sm$ and $^{131}Eu$
nuclei. A comparison of the results with the direct solution of the
Schroedinger equation shows that the method can be confidently applied also in
coupled-channel situations requiring high numerical accuracy.",0001037v1
1998-11-16,Faraday waves on a viscoelastic liquid,"We investigate Faraday waves on a viscoelastic liquid. Onset measurements and
a nonlinear phase diagram for the selected patterns are presented. By virtue of
the elasticity of the material a surface resonance synchronous to the external
drive competes with the usual subharmonic Faraday instability. Close to the
bicriticality the nonlinear wave interaction gives rise to a variety of novel
surface states: Localised patches of hexagons, hexagonal superlattices,
coexistence of hexagons and lines. Theoretical stability calculations and
qualitative resonance arguments support the experimental observations.",9811004v1
2000-01-31,Formation of Patterns in Intense Hadron Beams. The Amplitude Equation Approach,"We study the longitudinal motion of beam particles under the action of a
single resonator wave induced by the beam itself. Based on the method of
multiple scales we derive a system of coupled amplitude equations for the
slowly varying part of the longitudinal distribution function and for the
resonator wave envelope, corresponding to an arbitrary wave number. The
equation governing the slow evolution of the voltage envelope is show to be of
Ginzburg-Landau type.",0001073v1
2002-08-01,Husimi functions at dielectric interfaces: Inside-outside duality for optical systems and beyond,"We introduce generalized Husimi functions at the interfaces of dielectric
systems. Four different functions can be defined, corresponding to the incident
and departing wave on both sides of the interface. These functions allow to
identify mechanisms of wave confinement and escape directions in optical
microresonators, and give insight into the structure of resonance wave
functions. Off resonance, where systematic interference can be neglected, the
Husimi functions are related by Snell's law and Fresnel's coefficients.",0208006v1
1999-06-14,The Influence of Superpositional Wave Function Oscillations on Shor's Quantum Algorithm,"We investigate the influence of superpositional wave function oscillations on
the performance of Shor's quantum algorithm for factorization of integers. It
is shown that the wave function oscillations can destroy the required quantum
interference. This undesirable effect can be routinely eliminated using a
resonant pulse implementation of quantum computation, but requires special
analysis for non-resonant implementations.",9906045v1
2007-01-29,Infinite plane wave evolution in a 1-D square quantum barrier,"We analytically compute the time evolution of an initial infinite plane wave
in the presence of a 1-dimensional square quantum barrier. This calculation
generalizes the analysis of the shutter problem and sets the basis for the
calculation of the transmission of general wave packets, aiming to work out the
explicit contribution of the resonant (Gamow) states. The method relies mainly
on the analytical properties of the Green function. The role of separate
boundary conditions on the Green function and on the evolution equation is
highlighted. As in previous works on related problems, only the determination
of the resonant momenta requires numerical methods.",0701213v1
2007-07-08,A Dynamical Effective Medium Theory for Elastic Metamaterials,"We develop a dynamical effective medium theory to accurately predict the
unusual properties of elastic metamaterials in two dimensions near the resonant
frequencies. The theory shows that the effective bulk modulus, shear modulus,
and mass density can be made negative by choosing proper resonant scatterers,
leading to 8 possible types of wave propagation. The theory not only provides a
convenient tool to search for various metamaterials with desired properties,
but also gives a unified physical picture of these properties. Here we
demonstrate two examples. One possesses large band gaps at low frequencies. The
other exhibits two regions of negative refraction: one for both longitudinal
and transverse waves and the other for longitudinal waves only.",0707.1071v1
2008-01-10,Coherent Delocalization of Atomic Wave Packets in Driven Lattice Potentials,"Atomic wave packets loaded into a phase-modulated vertical optical-lattice
potential exhibit a coherent delocalization dynamics arising from intraband
transitions among Wannier-Stark levels. Wannier-Stark intraband transitions are
here observed by monitoring the in situ wave-packet extent. By varying the
modulation frequency, we find resonances at integer multiples of the Bloch
frequency. The resonances show a Fourier-limited width for interrogation times
up to 2 s. This can also be used to determine the gravity acceleration with ppm
resolution.",0801.1570v1
2008-05-01,Resonant speed meter for gravitational wave detection,"Gravitational-wave detectors have been well developed and operated with high
sensitivity. However, they still suffer from mirror displacement noise. In this
paper, we propose a resonant speed meter, as a displacement noise-canceled
configuration based on a ring-shaped synchronous recycling interferometer. The
remarkable feature of this interferometer is that, at certain frequencies,
gravitational-wave signals are amplified, while displacement noises are not.",0805.0102v1
2008-08-06,Resonance effects due to the excitation of surface Josephson plasma waves in layered superconductors,"We analytically examine the excitation of surface Josephson plasma waves
(SJPWs) in periodically-modulated layered superconductors. We show that the
absorption of the incident electromagnetic wave can be substantially increased,
for certain incident angles, due to the resonance excitation of SJPWs. The
absorption increase is accompanied by the decrease of the specular reflection.
Moreover, we find the physical conditions guaranteeing the total absorption
(and total suppression of the specular reflection). These conditions can be
realized for Bi2212 superconductor films.",0808.0850v1
2009-07-25,Discrete Wave Turbulence,"In this Letter we present discrete wave turbulence (DWT) as a counterpart of
classical statistical wave turbulence (SWT). DWT is characterized by resonance
clustering, not by the size of clusters, i.e. it includes, but is not reduced
to, the study of low-dimensional systems. Clusters with integrable and chaotic
dynamics co-exist in different sub-spaces of the $\mathbf{k}$-space.
NR-diagrams are introduced, a handy graphical presentation of an arbitrary
resonance cluster allowing to reconstruct uniquely dynamical system describing
the cluster. DWT is shown to be a novel research field in nonlinear science,
with its own methods, achievements and application areas.",0907.4406v2
2011-01-05,Current limiting effects on laser compression by resonant backward Raman scattering,"Through resonant backward Raman scattering, the plasma wave mediates the
energy transfer between long pump and short seed laser pulses. These mediation
can result in pulse compression at extraordinarily high powers. However, both
the overall efficiency of the energy transfer and the duration of the amplified
pulse depend upon the persistence of the plasma wave excitation. At least with
respect to the recent state-of-the-art experiments, it is possible to deduce
that at present the experimentally realized efficiency of the amplifier is
likely constrained mainly by two effects, namely the pump chirp and the plasma
wave wavebreaking.",1101.0861v1
2011-04-14,Parametric Resonance in Wave Maps,"In this note we concern with the wave maps from the Lorentzian manifold with
the periodic in time metric into the Riemannian manifold, which belongs to the
one-parameter family of Riemannian manifolds. That family contains as a special
case the Poincare upper half-plane model. Our interest to such maps is
motivated with some particular type of the Robertson-Walker spacetime arising
in the cosmology. We show that small periodic in time perturbation of the
Minkowski metric generates parametric resonance phenomenon. We prove that, the
global in time solvability in the neighborhood of constant solutions is not a
stable property of the wave maps.",1104.2883v2
2013-05-30,Resonant Compton scattering of electromagnetic waves in a quantum plasma,"We consider the resonant scattering of coherent electromagnetic waves by a
Raman-like process in the gamma ray range off electrostatic modes in a quantum
plasma using a collective Klein-Gordon-Maxwell model. The growth rates for the
most unstable modes are calculated theoretically, and the results are found to
be more efficient than incoherent Compton scattering off individual electrons
above a critical amplitude of the electromagnetic wave. The model does not
predict Raman scattering off pair modes that exist in the Klein-Gordon-Maxwell
model. The results are relevant for coherent gamma rays created in forthcoming
laboratory experiments or in astrophysical objects.",1305.7195v1
2013-11-11,Reconfigurable nonreciprocity with nonlinear Fano diode,"We propose a dynamically tunable nonreciprocal response for wave propagations
by employing nonlinear Fano resonances. We demonstrate that transmission
contrast of waves propagation in opposite directions can be controlled by
excitation signal. In particular, the unidirectional transmission can be
flipped at different times of a pulse, resembling a diode operation with {\em
dynamical reconfigurable nonreciprocity}. The key mechanism is the interaction
between the linear and nonlinear Fano resonances that allows for the tunable
unidirectional wave propagation and ultrahigh transmission contrast ratio. We
further present a realistic photonic example which demonstrates the properties
of nonreciprocity can be dynamically manipulated using a pump pulse, based on
the general theoretical model.",1311.2533v1
2014-01-21,Non-destructive testing of composite plates by holographic vibrometry,"We report on a wide-field optical monitoring method for revealing local
delaminations in sandwich-type composite plates at video-rate by holographic
vibrometry. Non-contact measurements of low frequency flexural waves is
performed with time-averaged heterodyne holography. It enables narrowband
imaging of local out-of-plane nanometric vibration amplitudes under sinusoidal
excitation, and reveals delamination defects, which cause local resonances of
flexural waves. The size of the defect can be estimated from the first
resonance frequency of the flexural wave and the mechanical parameters of the
observed layer of the composite plate.",1401.5430v1
2014-04-30,Robust energy transfer mechanism via precession resonance in nonlinear turbulent wave systems,"A robust energy transfer mechanism is found in nonlinear wave systems, which
favours transfers towards modes interacting via triads with nonzero frequency
mismatch, applicable in meteorology, nonlinear optics and plasma wave
turbulence. We introduce the concepts of truly dynamical degrees of freedom and
triad precession. Transfer efficiency is maximal when the triads' precession
frequencies resonate with the system's nonlinear frequencies, leading to a
collective state of synchronised triads with strong turbulent cascades at
intermediate nonlinearity. Numerical simulations confirm analytical
predictions.",1404.7833v1
2015-01-07,Polarization rotation by an rf-SQUID metasurface,"We study the transmission and reflection of a plane electromagnetic wave
through a two dimensional array of rf-SQUIDs. The basic equations describing
the amplitudes of the magnetic field and current in the split-ring resonators
are developed. These yield in the linear approximation the reflection and
transmission coefficients. The polarization of the reflected wave is
independent of the frequency of the incident wave and of its polarization; it
is defined only by the orientation of the split-ring. The reflection and
transmission coefficients have a strong resonance that is determined by the
parameters of the rf-SQUID; its strength depends essentially on the incident
angle.",1501.01536v1
2015-11-02,Design of a 325MHz Half Wave Resonator prototype at IHEP,"A 325MHz beta=0.14 superconducting half wave resonator(HWR) prototype has
been developed at the Institute of High Energy Physics(IHEP), which can be
applied in continuous wave (CW) high beam proton accelerators. In this paper,
the electromagnetic (EM) design, multipacting simulation, mechanical
optimization, and fabrication are introduced in details. In vertical test at
4.2K, the cavity reached Eacc=7MV/m with Q0=1.4*10^9 and Eacc=15.9MV/m with
Q0=4.3*10^8.",1511.00456v1
2016-05-24,Dielectric Resonator Metasurface for Dispersion Engineering,"We introduce a practical dielectric metasurface design for microwave
frequencies. The metasurface is made of an array of dielectric resonators held
together by dielectric connections thus avoiding the need of a mechanical
support in the form of a dielectric slab and the spurious multiple reflections
that such a slab would generate. The proposed design can be used either for
broadband metasurface applications or monochromatic wave transformations. The
capabilities of the concept to manipulate the transmission phase and amplitude
of the metasurface are supported by numerical and experimental results.
Finally, a half-wave plate and a quarter-wave plate have been realized with the
proposed concept.",1605.07487v1
2016-06-06,Enhanced harmonic generation and wave-mixing via two-color multiphoton excitation of atoms/molecules,"We consider harmonics generation and wave-mixing by two-color multi photon
resonant excitation of three-level atoms/molecules in strong laser fields. The
coherent part of the spectra corresponding to multicolor harmonics generation
is investigated. The obtained analytical results on the basis of generalized
rotating wave approximation are in a good agreement with numerical
calculations. The results applied to the hydrogen atom and homonuclear diatomic
molecular ion show that one can achieve efficient generation of moderately high
multicolor harmonics via multiphoton resonant excitation by appropriate laser
pulses.",1606.01705v1
2020-03-24,The Effect of Discrete Resonant Manifold Structure on Discrete Wave Turbulence,"We consider the long-term dynamics of nonlinear dispersive waves in a finite
periodic domain. The purpose of the work is to show that the statistical
properties of the wave field rely critically on the structure of the discrete
resonant manifold (DRM). To demonstrate this, we simulate the two-dimensional
MMT equation on rational and irrational tori, resulting in remarkably different
power-law spectra and energy cascades at low nonlinearity levels. The
difference is explained in terms of different structures of the DRM, which
makes use of recent number theory results.",2003.10801v3
2020-11-06,Wave interaction with subwavelength resonators,"The aim of this review is to cover recent developments in the mathematical
analysis of subwavelength resonators. The use of sophisticated mathematics in
the field of metamaterials is reported, which provides a mathematical framework
for focusing, trapping, and guiding of waves at subwavelength scales.
Throughout this review, the power of layer potential techniques combined with
asymptotic analysis for solving challenging wave propagation problems at
subwavelength scales is demonstrated.",2011.03575v1
2017-04-20,Transmission time and resonant tunneling through barriers using localized quantum density soliton waves,"In this paper, the interaction and transmission time of quantum density
solitons waves representing particles passing through finite barrier potentials
is investigated. Using the conservation of energy and of quantum density, it is
first demonstrated that these waves have finite de Broglie wavelength and
represent particles in quantum theory. The passage of the quantum density
solitons (particles) through barriers of finite energies is then shown to lead
to the phenomena of resonant tunneling and, in Josephson-like configurations,
to the quantization of magnetic flux. A precise general measure for barrier
tunneling time is derived which is found to give a new interpretation of the
quantum indeterminacy principles.",1704.06587v1
2021-10-31,Gravitomagnetic resonance and gravitational waves,"We show that using Fermi coordinates it is possible to describe the
gravitational field of a wave using a gravitoelectromagnetic analogy. In
particular, we show that using this approach, a new phenomenon, called
gravitomagnetic resonance, may appear. We describe it both from classical and
quantum viewpoints, and suggest that it could in principle be used as the basis
for a new type of gravitational wave detectors.",2111.00502v1
2022-05-02,Resonant string behavior in a Gravitational Wave burst,"We investigate the behavior of classical closed strings in a gravitational
wave burst and discover an intriguing resonant behavior where the energy
absorbed by the strings is crucially dependent on the amplitude and frequency
of the gravitational wave. This behavior can be traced to the well-known
behavior of the solutions to the Mathieu equation.",2205.01007v2
2023-09-19,Resonant X-Ray Scattering Investigations of Charge Density Wave and Nematic Orders in Cuprate Superconductors,"In the cuprate superconductors, superconductivity often co-exists with other
types of order, including charge density wave and nematic orders. Over the past
decade, resonant x-ray scattering has emerged as a key tool to investigate
these competing/coexisting orders, providing valuable insights into their
microscopic character. In this report we provide a brief review of the
technique and highlight selected recent advances in study charge density wave
order and nematic order in the cuprates.",2309.10905v1
2015-09-23,Tilting Saturn without tilting Jupiter: Constraints on giant planet migration,"The migration and encounter histories of the giant planets in our Solar
System can be constrained by the obliquities of Jupiter and Saturn. We have
performed secular simulations with imposed migration and N-body simulations
with planetesimals to study the expected obliquity distribution of migrating
planets with initial conditions resembling those of the smooth migration model,
the resonant Nice model and two models with five giant planets initially in
resonance (one compact and one loose configuration). For smooth migration, the
secular spin-orbit resonance mechanism can tilt Saturn's spin axis to the
current obliquity if the product of the migration time scale and the orbital
inclinations is sufficiently large (exceeding 30 Myr deg). For the resonant
Nice model with imposed migration, it is difficult to reproduce today's
obliquity values, because the compactness of the initial system raises the
frequency that tilts Saturn above the spin precession frequency of Jupiter,
causing a Jupiter spin-orbit resonance crossing. Migration time scales
sufficiently long to tilt Saturn generally suffice to tilt Jupiter more than is
observed. The full N-body simulations tell a somewhat different story, with
Jupiter generally being tilted as often as Saturn, but on average having a
higher obliquity. The main obstacle is the final orbital spacing of the giant
planets, coupled with the tail of Neptune's migration. The resonant Nice case
is barely able to simultaneously reproduce the {orbital and spin} properties of
the giant planets, with a probability ~0.15%. The loose five planet model is
unable to match all our constraints (probability <0.08%). The compact five
planet model has the highest chance of matching the orbital and obliquity
constraints simultaneously (probability ~0.3%).",1509.06834v1
2016-12-17,Magnetic resonance study of bulk and thin film EuTiO3,"Magnetic resonance spectra of EuTiO3 in both bulk and thin film form were
taken at temperatures from 3-350 K and microwave frequencies from 9.2-9.8 and
34 GHz. In the paramagnetic phase, magnetic resonance spectra are determined by
magnetic dipole and exchange interactions between Eu2+ spins. In the film, a
large contribution arises from the demagnetization field. From detailed
analysis of the linewidth and its temperature dependence, the parameters of
spin-spin interactions were determined: the exchange frequency is 15-15.5 GHz
and the estimated critical exponent of the spin correlation length is ~ 0.5. In
the bulk samples, the spectra exhibited a distinct minimum in the linewidth at
the N\'eel temperature, T_N = 5.5 K, while the resonance field practically does
not change even on cooling below T_N. This is indicative of a small magnetic
anisotropy ~ 320 G in the antiferromagnetic phase. In the film, the magnetic
resonance spectrum is split below T_N into several components due to excitation
of the magnetostatic modes, corresponding to a non-uniform precession of
magnetization. Moreover, the film was observed to degrade over two years. This
was manifested by an increase of defects and a change in the domain structure.
The saturated magnetization in the film, estimated from the magnetic resonance
spectrum, was about 900 emu/cm3 or 5.5 mu_B/unit cell at T = 3.5 K.",1612.05781v1
2021-04-18,Exotic resonances of fully-heavy tetraquarks in a lattice-QCD insipired quark model,"Fully-heavy tetraquark states, i.e. $cc\bar{c}\bar{c}$, $bb\bar{b}\bar{b}$,
$bb\bar{c}\bar{c}$ ($cc\bar{b}\bar{b}$), $cb\bar{c}\bar{c}$,
$cb\bar{b}\bar{b}$, and $cb\bar{c}\bar{b}$, are systematically investigated by
means of a non-relativistic quark model based on lattice-QCD studies of the
two-body $Q\bar{Q}$ interaction, which exhibits a spin-independent Cornell
potential along with a spin-spin term. The four-body problem is solved using
the Gaussian expansion method; additionally, the so-called complex scaling
technique is employed so that bound, resonance, and scattering states can be
treated on the same footing. Moreover, a complete set of four-body
configurations, including meson-meson, diquark-antidiquark, and K-type
configurations, as well as their couplings, are considered for spin-parity
quantum numbers $J^{P(C)}=0^{+(+)}$, $1^{+(\pm)}$, and $2^{+(+)}$ in the
$S$-wave channel. Several narrow resonances, with two-meson strong decay widths
less than 30 MeV, are found in all of the tetraquark systems studied.
Particularly, the fully-charm resonances recently reported by the LHCb
Collaboration, at the energy range between 6.2 and 7.2 GeV in the di-$J/\psi$
invariant spectrum, can be well identified in our calculation. Focusing on the
fully-bottom tetraquark spectrum, resonances with masses between 18.9 and 19.6
GeV are found. For the remaining charm-bottom cases, the masses are obtained
within a energy region from 9.8 GeV to 16.4 GeV. All these predicted resonances
can be further examined in future experiments.",2104.08814v1
2019-04-15,Accurate modelling of the low-order secondary resonances in the spin-orbit problem,"We provide an analytical approximation to the dynamics in each of the three
most important low order secondary resonances (1:1, 2:1, and 3:1) bifurcating
from the synchronous primary resonance in the gravitational spin-orbit problem.
To this end we extend the perturbative approach introduced in Gkolias et. al.
(2016), based on normal form series computations. This allows to recover
analytically all non-trivial features of the phase space topology and
bifurcations associated with these resonances. Applications include the
characterization of spin states of irregular planetary satellites or double
systems of minor bodies with irregular shapes. The key ingredients of our
method are: i) the use of a detuning parameter measuring the distance from the
exact resonance, and ii) an efficient scheme to `book-keep' the series terms,
which allows to simultaneously treat all small parameters entering the problem.
Explicit formulas are provided for each secondary resonance, yielding i) the
time evolution of the spin state, ii) the form of phase portraits, iii) initial
conditions and stability for periodic solutions, and iv) bifurcation diagrams
associated with the periodic orbits. We give also error estimates of the
method, based on analyzing the asymptotic behavior of the remainder of the
normal form series.",1904.07047v1
2022-09-29,Nonlinearity and Parametric Amplification of Superconducting Nanowire Resonators in Magnetic Field,"Nonlinear superconducting devices, typically based on Josephson Junction (JJ)
nonlinearities, are the basis for superconducting quantum electronics,
enabling, e.g., the formation of isolated two-level superconducting qubits and
amplifiers. While emerging spin, hybrid spin/superconducting (including
Majorana), and nano-magneto-optical quantum systems could benefit tremendously
from superconducting nonlinearities, the presence of strong magnetic fields in
these systems are incompatible with conventional JJ devices, which are highly
sensitive to applied magnetic fields. One potential solution is the use of
kinetic inductance (KI) nonlinearity. To date, only linear kinetic inductance
(KI) devices have been shown to operate in high magnetic fields, while
nonlinear KI device operation in high magnetic fields has received virtually no
attention. Here, we study the nonlinearity of superconducting nanowire (NW) KI
resonators and their performance as parametric amplifiers for in-plane magnetic
fields. We study the Kerr coefficients of NW KI resonators made from 10 nm-thin
NbTiN films with characteristic impedance up to 3 k$\Omega$, and demonstrate
both nondegenerate and degenerate parametric amplification, at magnetic fields
up to 2 T, for the first time. We find that narrow KI resonators of width 0.1
$\mu$m are robust, in terms of gain, dynamic range and noise, to magnetic
fields up to $\sim$2 T, while wider KI resonators of width 1 $\mu$m suffer
significant suppression in the gain around at fields well below 2 T. Around 8
dB deamplification is observed for coherent states for a 0.1 $\mu$m KI
resonator, implying the capability of noise squeezing. These results open a new
pathway to developing nonlinear quantum devices that operate in or generate
high magnetic fields such as spin, hybrid spin/superconducting, and
magneto-opto-mechanical devices.",2209.14523v1
2023-03-01,Spectrum of Feshbach resonances in NaLi $+$ Na collisions,"Collisional resonances of molecules can offer a deeper understanding of
interaction potentials and collision complexes, and allow control of chemical
reactions. Here, we experimentally map out the spectrum of Feshbach resonances
in collisions between ultracold triplet ro-vibrational ground-state NaLi
molecules and Na atoms over a range of 1400 G. Preparation of the
spin-stretched state puts the system initially into the non-reactive quartet
potential. A total of 25 resonances are observed, in agreement with
quantum-chemistry calculations using a coupled-channels approach. Although the
theory cannot predict the positions of resonances, it can account for several
experimental findings and provide unprecedented insight into the nature and
couplings of ultracold, strongly interacting complexes. Previous work has
addressed only weakly bound complexes. We show that the main coupling mechanism
results from spin-rotation and spin-spin couplings in combination with the
anisotropic atom-molecule interaction, and that the collisional complexes which
support the resonances have a size of 30-40 $a_0$. This study illustrates the
potential of a combined experimental and theoretical approach.",2303.00863v1
2023-11-13,Origin of reduced dynamical friction by dark matter halos with net prograde rotation,"We provide an explanation for the reduced dynamical friction on galactic bars
in spinning dark matter halos. Earlier work based on linear theory predicted an
increase in dynamical friction when dark halos have a net forward rotation,
because prograde orbits couple to bars with greater strength than retrograde
orbits. Subsequent numerical studies, however, found the opposite trend:
dynamical friction weakens with increasing spin of the halo. We revisit this
problem and demonstrate that linear theory in fact correctly predicts a reduced
torque in forward-rotating halos. We show that shifting the halo mass from
retrograde to prograde phase space generates a positive gradient in the
distribution function near the origin of the z-angular momentum (Lz=0), which
results in a resonant transfer of Lz to the bar, making the net dynamical
friction weaker. While this effect is subdominant for the major resonances,
including the corotation resonance, it leads to a significant positive torque
on the bar for the series of direct radial resonances, as these resonances are
strongest at Lz=0. The overall dynamical friction from spinning halos is shown
to decrease with the halo's spin, in agreement with the secular behavior of
N-body simulations. We validate our linear calculation by computing the
nonlinear torque from individual resonances using the angle-averaged
Hamiltonian.",2311.07640v2
2009-07-02,Gravitational-wave detectability of equal-mass black-hole binaries with aligned spins,"Binary black-hole systems with spins aligned or anti-aligned to the orbital
angular momentum provide the natural ground to start detailed studies of the
influence of strong-field spin effects on gravitational wave observations of
coalescing binaries. Furthermore, such systems may be the preferred end-state
of the inspiral of generic supermassive binary black-hole systems. In view of
this, we have computed the inspiral and merger of a large set of binary systems
of equal-mass black holes with spins parallel to the orbital angular momentum
but otherwise arbitrary. Our attention is particularly focused on the
gravitational-wave emission so as to quantify how much spin effects contribute
to the signal-to-noise ratio, to the horizon distances, and to the relative
event rates for the representative ranges in masses and detectors. As expected,
the signal-to-noise ratio increases with the projection of the total black hole
spin in the direction of the orbital momentum. We find that equal-spin binaries
with maximum spin aligned with the orbital angular momentum are more than
""three times as loud"" as the corresponding binaries with anti-aligned spins,
thus corresponding to event rates up to 30 times larger. We also consider the
waveform mismatch between the different spinning configurations and find that,
within our numerical accuracy, binaries with opposite spins S_1=-S_2 cannot be
distinguished whereas binaries with spin S_1=S_2 have clearly distinct
gravitational-wave emissions. Finally, we derive a simple expression for the
energy radiated in gravitational waves and find that the binaries always have
efficiencies E_rad/M > 3.6%, which can become as large as E_rad/M = 10% for
maximally spinning binaries with spins aligned with the orbital angular
momentum.",0907.0462v2
2009-09-21,Spin Waves and Switching: The Dynamics of Exchange - Biased Co Core - CoO Shell Nanoparticles,"The utility of nanoscaled ferromagnetic particles requires both stabilized
moments and maximized switching speeds. During reversal, the spatial modulation
of the nanoparticle magnetization evolves in time, and the energy differences
between each new configuration are accomodated by the absorption or emission
spin waves with different wavelengths and energy profiles. The switching speed
is limited by how quickly this spin wave energy is dissipated. We present here
the first observation of dispersing spin waves in a nanoscaled system, using
neutron scattering to detect spin waves in the CoO shells of exchange biased Co
core- CoO shell nanoparticles. Their dispersion is little affected by finite
size effects, but the spectral weight shifts to energies and wave vectors which
increase with decreasing system size. Core-shell coupling leads to a
substantial enhancement of the CoO spin wave population above its conventional
thermal level, suggesting a new mechanism for dissipating core switching
energy.",0909.3833v1
2018-04-14,Interplay of Wave Localization and Turbulence in Spin Seebeck Effect,"One of the most important discoveries in spintronics is the spin Seebeck
effect (SSE) recently observed in both insulating and (semi-)conducting
magnets. However, the very existence of the effect in transverse configuration
is still a subject of current debates, due to conflicting results reported in
different experiments. Present understanding of the SSE is mainly based on a
particle-like picture with the local equilibrium approximation (LEA), i.e.,
spatially resolved temperature-field assumed to describe the system. In this
work, we abandon the LEA to some extent and develop a wave theory to explain
the SSE, by highlighting the interplay between wave localization and
turbulence. We show that the emerging SSE with a sign change in the
high/low-temperature regions is closely related to the extendedness of the spin
wave that senses an average temperature of the system. On the one hand,
ubiquitous disorders (or magnetic field gradients) can strongly suppress the
transverse spin Seebeck effect (TSSE) due to Anderson (or Wannier-Zeeman)
spin-wave localization. On the other hand, the competing wave turbulence of
interacting magnons tends to delocalize the wave, and thus remarkably revives
the TSSE before the magnon self-trapping. Our theory provides a promising route
to resolve the heated debate on TSSE with a clear experiment scheme to test it
in future spin caloritronic devices.",1804.05157v1
2020-09-04,Experimental observation of the curvature-induced asymmetric spin-wave dispersion in hexagonal nanotubes,"Theoretical and numerical studies on curved magnetic nano-objects predict
numerous exciting effects that can be referred to as magneto-chiral effects,
which do not originate from the intrinsic Dzyaloshinskii-Moriya interaction or
surface-induced anisotropies. The origin of these chiral effects is the
isotropic exchange or the dipole-dipole interaction present in all magnetic
materials but renormalized by the curvature. Here, we demonstrate
experimentally that curvature induced effects originating from the
dipole-dipole interaction are directly observable by measuring spin-wave
propagation in magnetic nanotubes with hexagonal cross section using time
resolved scanning transmission X-ray microscopy. We show that the dispersion
relation is asymmetric upon reversal of the wave vector when the propagation
direction is perpendicular to the static magnetization. Therefore
counter-propagating spin waves of the same frequency exhibit different
wavelenghts. Hexagonal nanotubes have a complex dispersion, resulting from
spin-wave modes localised to the flat facets or to the extremely curved regions
between the facets. The dispersion relations obtained experimentally and from
micromagnetic simulations are in good agreement. %The asymmetric spin-wave
transport is present for all modes, promoting hexagonal nanotubes for magnonic
applications. These results show that spin-wave transport is possible in 3D,
and that the dipole-dipole induced magneto-chiral effects are significant.",2009.02238v1
2016-11-23,Magnetometer Based On Spin Wave Interferometer,"We describe magnetic field sensor based on spin wave interferometer. Its
sensing element consists of a magnetic cross junction with four micro-antennas
fabricated at the edges. Two of these antennas are used for spin wave
excitation and two others antennas are used for the detection of the inductive
voltage produced by the interfering spin waves. Two waves propagating in the
orthogonal arms of the cross may accumulate significantly different phase
shifts depending on the magnitude and the direction of the external magnetic
field. This phenomenon is utilized for magnetic field sensing. The sensitivity
has maximum at the destructive interference condition, where a small change of
the external magnetic field results in a drastic increase of the inductive
voltage as well as the change of the output phase. We report experimental data
obtained on a micrometer scale Y3Fe2(FeO4)3 cross structure. The change of the
inductive voltage near the destructive interference point exceeds 40 dB per 1
Oe. At the same time, the phase of the output exhibit a {\pi}-phase shift
within 1 Oe. The data are collected for three different orientations of the
sensor in magnetic field at room temperature. Taking into account low thermal
noise in ferrite structures, the maximum sensitivity of spin wave magnetometer
may exceed atta Tesla. Other appealing advantages include compactness, fast
data acquisition and wide temperature operating range. The physical limits of
spin wave interferometers are also discussed.",1611.08015v1
2013-09-13,The behavior of transverse waves in nonuniform solar flux tubes. I. Comparison of ideal and resistive results,"Magnetohydrodynamic (MHD) waves are ubiquitously observed in the solar
atmosphere. Kink waves are a type of transverse MHD waves in magnetic flux
tubes that are damped due to resonant absorption. The theoretical study of kink
MHD waves in solar flux tubes is usually based on the simplification that the
transverse variation of density is confined to a nonuniform layer much thinner
than the radius of the tube, i.e., the so-called thin boundary approximation.
Here, we develop a general analytic method to compute the dispersion relation
and the eigenfunctions of ideal MHD waves in pressureless flux tubes with
transversely nonuniform layers of arbitrary thickness. Results for kink waves
are produced and are compared with fully numerical resistive MHD eigenvalue
computations in the limit of small resistivity. We find that the frequency and
resonant damping rate are the same in both ideal and resistive cases. The
actual results for thick nonuniform layers deviate from the behavior predicted
in the thin boundary approximation and strongly depend on the shape of the
nonuniform layer. The eigenfunctions in ideal MHD are very different from those
in resistive MHD. The ideal eigenfunctions display a global character
regardless of the thickness of the nonuniform layer, while the resistive
eigenfunctions are localized around the resonance and are indistinguishable
from those of ordinary resistive Alfv\'en modes. Consequently, the spatial
distribution of wave energy in the ideal and resistive cases is dramatically
different. This poses a fundamental theoretical problem with clear
observational consequences.",1309.3423v1
2020-08-18,A Quasi-Linear Diffusion Model for Resonant Wave-Particle Instability in Homogeneous Plasma,"In this paper, we develop a model to describe the generalized wave-particle
instability in a quasi-neutral plasma. We analyze the quasi-linear diffusion
equation for particles by expressing an arbitrary unstable and resonant wave
mode as a Gaussian wave packet, allowing for an arbitrary direction of
propagation with respect to the background magnetic field. We show that the
localized energy density of the Gaussian wave packet determines the
velocity-space range in which the dominant wave-particle instability and
counter-acting damping contributions are effective. Moreover, we derive a
relation describing the diffusive trajectories of resonant particles in
velocity space under the action of such an interplay between the wave-particle
instability and damping. For the numerical computation of our theoretical
model, we develop a mathematical approach based on the Crank-Nicolson scheme to
solve the full quasi-linear diffusion equation. Our numerical analysis solves
the time evolution of the velocity distribution function under the action of a
dominant wave-particle instability and counteracting damping and shows a good
agreement with our theoretical description. As an application, we use our model
to study the oblique fast-magnetosonic/whistler instability, which is proposed
as a scattering mechanism for strahl electrons in the solar wind. In addition,
we numerically solve the full Fokker-Planck equation to compute the time
evolution of the electron-strahl distribution function under the action of
Coulomb collisions with core electrons and protons after the collisionless
action of the oblique fast-magnetosonic/whistler instability.",2008.08169v2
2022-03-09,Explosive instability of dust settling in a protoplanetary disc,"It is shown that gas-dust perturbations in a disc with dust settling to the
disc midplane exhibit the non-linear three-wave resonant interactions between
streaming dust wave (SDW) and two inertial waves (IW). In the particular case
considered in this paper, SDW at the wavenumber $k^\bullet = 2\kappa / (g_z
t_s)$, where $\kappa$, $g_z$ and $t_s$ are, respectively, epicyclic frequency,
vertical gravitational acceleration and particle's stopping time, interacts
with two IW at the lower wavenumbers $k^\prime$ and $k^{\prime\prime}$ such
that $k^\prime < k_{\rm DSI} < k^{\prime\prime} < k^\bullet$, where $k_{\rm
DSI} = \kappa / (g_z t_s)$ is the wavenumber of the linear resonance between
SDW and IW associated with the previously discovered linear dust settling
instability. The problem is solved analytically in the limit of the small dust
fraction. As soon as the dynamical dust back reaction on gas is taken into
account, ${\bf k}^\bullet$, ${\bf k}^\prime$ and ${\bf k}^{\prime\prime}$
become slightly non-collinear and the emerging interaction of waves leads to
simultaneous explosive growth of their amplitudes. This growth is explained by
the conservative exchange with energy between the waves. The amplitudes of all
three waves grow because the negative energy SDW transfers its energy to the
positive energy IW. The product of the dimensionless amplitude of initially
dominant wave and the time of explosion can be less than Keplerian time in a
disc. It is shown that, generally, the three-wave resonance of an explosive
type exists in a wide range of wavenumbers $0 < k^\bullet \leq 2\kappa / (g_z
t_s)$. An explosive instability of gas-dust mixture may facilitate the dust
clumping and the subsequent formation of planetesimals in young protoplanetary
discs.",2203.04792v1
2022-03-29,Bulk charge density wave and electron-phonon coupling in superconducting copper oxychlorides,"Bulk charge density waves are now reported in nearly all high-temperature
superconducting cuprates, with the noticeable exception of one particular
family: the copper oxychlorides. Here, we used resonant inelastic X-ray
scattering to reveal a bulk charge density waves in these materials. Combining
resonant inelastic X-ray scattering with non-resonant inelastic X-ray
scattering, we investigate the interplay between the lattice excitations and
the charge density wave, and evidence the phonon anomalies of the Cu-O
bond-stretching mode at the charge density wave wave-vector. We propose that
such electron-phonon anomalies occur in the presence of dispersive charge
excitations emanating from the charge density wave and interacting with the
Cu-O bond-stretching phonon. Our results pave the way for future studies,
combining both bulk and surface probes, to investigate the static and dynamical
properties of the charge density wave in the copper oxychloride family.",2203.15311v2
2023-07-30,Broadband Dispersive-Wave Emission Coupled with Two-Stage Soliton Self-Compression in Gas-Filled Anti-Resonant Hollow-Core Fibers,"We studied the underlying mechanism of broadband dispersive-wave emission
within a resonance band of gas-filled anti-resonant hollow-core fiber. Both
theoretical and experimental results unveiled that the high-order soliton,
launched into the hollow-core fiber, experienced two stages of pulse
compression, resulting in a multi-peak structure of the dispersive-wave
spectrum. Over the first-stage pulse compression, a sharp increase of the pulse
peak power triggered the first time of dispersion-wave emission, and
simultaneously caused ionization of the noble gas filled in the fiber core.
Strong soliton-plasma interactions led to blue shifting of the pump pulse, and
the blue-shifted pulse experienced a decreasing dispersion value in the fiber
waveguide, resulting in an increase of its soliton order. Then, the
second-stage pulse compression due to the high-order soliton effect triggered
the second time of dispersive-wave emission at a phase-matched frequency
slightly lower than that in the first stage. Multi-peak spectra of the output
dispersive-waves and their formation dynamics were clearly observed in our
experiments, which can be understood using a delicate coupling mechanism among
three nonlinear effects including high-order-soliton compression,
soliton-plasma interaction and phase-matched dispersive-wave emission. The
output broadband dispersive-wave could be potentially compressed to sub-30 fs
duration using precise chirp-compensation technique.",2307.16147v1
2014-01-29,Nonreciprocal Dispersion of Spin Waves in Ferromagnetic Thin Films Covered with a Finite-Conductivity Metal,"We study the effect of one-side metallization of a uniform ferromagnetic thin
film on its spin-wave dispersion relation in the Damon-Eshbach geometry. Due to
the finite conductivity of the metallic cover layer on the ferromagnetic film
the spin-wave dispersion relation may be nonreciprocal only in a limited
wave-vector range. We provide an approximate analytical solution for the
spin-wave frequency, discuss its validity and compare it with numerical
results. The dispersion is analyzed systematically by varying the parameters of
the ferromagnetic film, the metal cover layer and the value of the external
magnetic field. The conclusions drawn from this analysis allow us to define a
structure based on a 30 nm thick CoFeB film with an experimentally accessible
nonreciprocal dispersion relation in a relatively wide wave-vector range.",1401.7454v1
2018-07-31,Electrostatic Langmuir and SEAWs in spin polarized plasma double layer,"The quantum hydrodynamic model of the electrostatic waves in the two parallel
layers of two dimensional electron gases (2DEGs) is developed. It is considered
for two regimes: classic regime and quantum regime with the separate spin
evolution. Two Langmuir-like waves are found in classic case which have an
interference-like pattern in the frequency dependence on concentration
$\omega^{2}\sim(n_{01}+n_{02}\pm2\sqrt{n_{01}n_{02}})$. They appear instead of
two 2D Langmuir waves in noninteracting 2DEGs. The spectrum of four waves is
found in the quantum regime. Two extra waves are related to the separate spin
evolution and associated to the spin-electron acoustic waves. The influence of
the quantum Bohm potential is considered either.",1807.11894v1
2018-10-09,Non-uniform spin wave softening in 2D magnonic crystals as a tool for opening omnidirectional magnonic band gaps,"By means of the plane wave method we study spin wave dynamics in
two-dimensional bi-component magnonic crystals based on a squeezed hexagonal
lattice and consist of a permalloy thin film with cobalt inclusions. We explore
the dependence of a spin wave frequency on the external magnetic field,
especially in weak fields where the mode softening takes place. For considered
structures, the mode softening proves to be highly non-uniform on both the mode
number and the wave vector. We found this effect to be responsible for the
omnidirectional band gap opening. Moreover, we show that the enhancement of the
demagnetizing field caused by the squeezing of the structure is of crucial
importance for the non-uniform mode softening. This allows us to employ this
mechanism to design magnonic gaps with different sensitivity for the tiny
change of the external field. The effects we have found should be useful in
designing and optimization of spin wave filters highly tunable by a small
external magnetic field.",1810.04005v3
2021-08-26,Gravitational waves from spinning neutron stars as not-quite-standard sirens,"As is well known, gravitational wave detections of coalescing binaries are
standard sirens, allowing a measurement of source distance by gravitational
wave means alone. In this paper we explore the analogue of this capability for
continuous gravitational wave emission from individual spinning neutron stars,
whose spin-down is driven purely by gravitational wave emission. We show that
in this case, the distance measurement is always degenerate with one other
parameter, which can be taken to be the moment of inertia of the star. We
quantify the accuracy to which such degenerate measurements can be made. We
also discuss the practical application of this method to scenarios where one or
other of distance or moment of inertia is constrained, breaking this degeneracy
and allowing a measurement of the remaining parameter. We consider a broad
range of possible, unknown parameters, as well as we present results for the
aLIGO and Einstein Telescope sensitivities. Our results will be of use
following the eventual detection of a neutron star spinning down through such
gravitational wave emission.",2108.11710v2
2017-03-11,Confined states in photonic-magnonic crystals with complex unit cell,"We have investigated multifunctional periodic structures in which
electromagnetic waves and spin waves can be confined in the same areas. Such
simultaneous localization of both sorts of excitations can potentially enhance
the interaction between electromagnetic waves and spin waves. The system we
considered has a form of one dimensional photonic-magnonic crystal with two
types of magnetic layers (thicker and thinner ones) separated by sections of
the dielectric photonic crystals. We focused on the electromagnetic defect
modes localized in the magnetic layers (areas where spin waves can be exited)
and decaying in the sections of conventional (nonmagnetic) photonic crystals.
We showed how the change of relative thickness of two types of the magnetic
layers can influence on the spectrum of spin waves and electromagnetic defect
modes, both localized in magnetic parts of the system.",1703.04013v1
2021-12-29,Excitation and detection of coherent sub-terahertz magnons in ferromagnetic and antiferromagnetic heterostructures,"Excitation of coherent high-frequency magnons (quanta of spin waves) is
critical to the development of high-speed magnonic devices. Here we
computationally demonstrate the excitation of coherent sub-terahertz (THz)
magnons in ferromagnetic (FM) and antiferromagnetic (AFM) thin films by a
photoinduced picosecond acoustic pulse. Analytical calculations are also
performed to reveal the magnon excitation mechanism. Through spin pumping and
spin-charge conversion, these magnons can inject sub-THz charge current into an
adjacent heavy-metal film which in turn emits electromagnetic (EM) waves. Using
a dynamical phase-field model that considers the coupled dynamics of acoustic
waves, spin waves, and EM waves, we show that the emitted EM wave retains the
spectral information of all the sub-THz magnon modes and has a sufficiently
large amplitude for near-field detection. These predictions indicate that the
excitation and detection of sub-THz magnons can be realized in rationally
designed FM or AFM thin-film heterostructures via ultrafast optical-pump
THz-emission-probe spectroscopy.",2112.14749v2
2023-05-29,Spinning Partial Waves for Scattering Amplitudes in $d$ Dimensions,"Partial wave decomposition is one of the main tools within the modern
S-matrix studies. We present a method to compute partial waves for $2\to2$
scattering of spinning particles in arbitrary spacetime dimension. We identify
partial waves as matrix elements of the rotation group with definite covariance
properties under a subgroup. This allows to use a variety of techniques from
harmonic analysis in order to construct a novel algebra of weight-shifting
operators. All spinning partial waves are generated by the action of these
operators on a set of known scalar seeds. The text is accompanied by a {\it
Mathematica} notebook to automatically generate partial waves. These results
pave the way to a systematic studies of spinning S-matrix bootstrap and
positivity bounds.",2305.18523v2
2006-03-28,Renormalization of the spin-wave spectrum in three-dimentional ferromagnets with dipolar interaction,"Renormalization of the spin-wave spectrum is discussed in a cubic ferromagnet
with dipolar forces at $T_C\gg T\ge0$. First 1/S-corrections are considered in
detail to the bare spectrum $\epsilon_{\bf k} = \sqrt{Dk^2 (Dk^2 +
S\omega_0\sin^2\theta_{\bf k})}$, where $D$ is the spin-wave stiffness,
$\theta_{\bf k}$ is the angle between $\bf k$ and the magnetization and
$\omega_0$ is the characteristic dipolar energy. In accordance with previous
results we obtain the thermal renormalization of constants $D$ and $\omega_0$
in the expression for the bare spectrum. Besides, a number of previously
unknown features are revealed. We observe terms which depend on azimuthal angle
of the momentum $\bf k$. It is obtained an isotropic term proportional to $k$
which makes the spectrum linear rather than quadratic when $\sin\theta_{\bf
k}=0$ and $k \ll \omega_0/D$. In particular a spin-wave gap proportional to
$\sin\theta_{\bf k}$ is observed. Essentially, thermal contribution from the
Hartree-Fock diagram to the isotropic correction as well as to the spin-wave
gap are proportional to the demagnetizing factor in the direction of domain
magnetization. This nontrivial behavior is attributed to the long-range nature
of the dipolar interaction. It is shown that the gap screens infrared
singularities of the first 1/S-corrections to the spin-wave stiffness and
longitudinal dynamical spin susceptibility (LDSS) obtained before. We
demonstrate that higher order 1/S-corrections to these quantities are small at
$T\ll\omega_0$. However the analysis of the entire perturbation series is still
required to derive the spectrum and LDSS when $T\gg\omega_0$.",0603741v2
2007-09-04,Spin Wave Magnetic NanoFabric: A New Approach to Spin-based Logic Circuitry,"We propose and describe a magnetic NanoFabric which provides a route to
building reconfigurable spin-based logic circuits compatible with conventional
electron-based devices. A distinctive feature of the proposed NanoFabric is
that a bit of information is encoded into the phase of the spin wave signal. It
makes possible to transmit information without the use of electric current and
utilize wave interference for useful logic functionality. The basic elements
include voltage-to-spin wave and wave-to-voltage converters, spin waveguides, a
modulator, and a magnetoelectric cell. As an example of a magnetoelectric cell,
we consider a two-phase piezoelectric-piezomagnetic system, where the spin wave
signal modulation is due to the stress-induced anisotropy caused by the applied
electric field. The performance of the basic elements is illustrated by
experimental data and results of numerical modeling. The combination of the
basic elements let us construct magnetic circuits for NOT and Majority logic
gates. Logic gates AND, OR, NAND and NOR are shown to be constructed as the
combination of NOT and a reconfigurable Majority gates. The examples of
computational architectures such as Cellular Automata, Cellular Nonlinear
Network and Field Programmable Gate Array are described. The main advantage of
the proposed NanoFabric is in the ability to realize logic gates with less
number of devices than it required for CMOS-based circuits. Potentially, the
area of the elementary reconfigurable Majority gate can be scaled down to
0.1um2. The disadvantages and limitations of the proposed NanoFabric are
discussed.",0709.0521v1
2010-11-12,Spin-Wave Spectrum in `Single-Domain' Magnetic Ground State of Triangular Lattice Antiferromagnet CuFeO2,"By means of neutron scattering measurements, we have investigated spin-wave
excitation in a collinear four-sublattice (4SL) magnetic ground state of a
triangular lattice antiferromagnet CuFeO2, which has been of recent interest as
a strongly frustrated magnet, a spin-lattice coupled system and a multiferroic.
To avoid mixing of spin-wave spectrum from magnetic domains having three
different orientations reflecting trigonal symmetry of the crystal structure,
we have applied uniaxial pressure on [1-10] direction of a single crystal
CuFeO2. By elastic neutron scattering measurements, we have found that only 10
MPa of the uniaxial pressure results in almost 'single domain' state in the 4SL
phase. We have thus performed inelastic neutron scattering measurements using
the single domain sample, and have identified two distinct spin- wave branches.
The dispersion relation of the upper spin-wave branch cannot be explained by
the previous theoretical model [R. S. Fishman: J. Appl. Phys. 103 (2008)
07B109]. This implies the importance of the lattice degree of freedom in the
spin-wave excitation in this system, because the previous calculation neglected
the effect of the spin-driven lattice distortion in the 4SL phase. We have also
discussed relationship between the present results and the recently discovered
""electromagnon"" excitation.",1011.2859v1
2020-06-03,Stochastic Core Spin-Up in Massive Stars -- Implications of 3D Simulations of Oxygen Shell Burning,"It has been suggested based on analytic theory that even in non-rotating
supernova progenitors stochastic spin-up by internal gravity waves (IGWs)
during the late burning stages can impart enough angular momentum to the core
to result in neutron star birth spin periods below 100ms, and a relatively firm
upper limit of 500ms for the spin period. We here investigate this process
using a 3D simulation of oxygen shell burning in a $3M_\odot$ He star. Our
model indicates that stochastic spin-up by IGWs is less efficient than
previously thought. We find that the stochastic angular momentum flux carried
by waves excited at the shell boundary is significantly smaller for a given
convective luminosity and turnover time than would be expected from simple
dimensional analysis. This can be explained by noting that the waves launched
by overshooting convective plumes contain modes of opposite angular wave number
with similar amplitudes, so that the net angular momentum of excited wave
packets almost cancels. We find that the wave-mediated angular momentum flux
from the oxygen shell follows a random walk, but again dimensional analysis
overestimates the random walk amplitudes since the correlation time is only a
fraction of the convective turnover time. Extrapolating our findings over the
entire life time of the last burning stages prior to collapse, we predict that
the core angular momentum from stochastic spin-up would translate into long
birth spin periods of several seconds for low-mass progenitors and no less than
100ms even for high-mass progenitors.",2006.02146v2
2021-07-21,Scattering in Black Hole Backgrounds and Higher-Spin Amplitudes: Part I,"The scattering of massless waves of helicity $|h|=0,\frac{1}{2},1$ in
Schwarzschild and Kerr backgrounds is revisited in the long-wavelenght regime.
Using a novel description of such backgrounds in terms of gravitating massive
particles, we compute classical wave scattering in terms of $2\to 2$ QFT
amplitudes in flat space, to all orders in spin. The results are Newman-Penrose
amplitudes which are in direct correspondence with solutions of the
Regge-Wheeler/Teukolsky equation. By introducing a precise prescription for the
point-particle limit, in Part I of this work we show how both agree for $h=0$
at finite values of the scattering angle and arbitrary spin orientation.
  Associated classical observables such as the scattering cross sections, wave
polarizations and time delay are studied at all orders in spin. The effect of
the black hole spin on the polarization and helicity of the waves is found in
agreement with previous analysis at linear order in spin. In the particular
limit of small scattering angle, we argue that wave scattering admits a
universal, point-particle description determined by the eikonal approximation.
We show how our results recover the scattering eikonal phase with spin up to
second post-Minkowskian order, and match it to the effective action of null
geodesics in a Kerr background. Using this correspondence we derive classical
observables such as polar and equatorial scattering angles.
  This study serves as a preceding analysis to Part II, where the Gravitational
Wave ($h=2$) case will be studied in detail.",2107.10179v2
2023-07-20,"The Role of $r$-Modes in Pulsar Spindown, Pulsar Timing and Gravitational Waves","Pulsars are fast-spinning neutron stars that lose their rotational energy via
various processes such as gravitational and electromagnetic radiation, particle
acceleration, and mass loss processes. Pulsar energy dissipation can be
quantified by a spin-down equation that measures the rate of change of pulsar
rotational frequency as a function of the frequency itself. We explore the
pulsar spin-down equation and consider the spin-down term up to the seventh
order in frequency. The seventh-order spin-down term accounts for energy
carried away in the form of gravitational radiation due to a current-type
quadrupole in the pulsar induced by r-modes. We derive analytical formulae of
pulsar r-mode gravitational wave frequency in terms of pulsar compactness,
tidal deformability, r-mode amplitude, and gravitational wave amplitude. We
find solutions to the above relationships using the Lambert-Tsallis and
Lambert-W functions. We also present an analytic solution of the pulsar
rotational period from the spin-down equation and numerically verify it for the
Crab pulsar PSR B0531+21. Accurate analysis of pulsar energy loss, spin-down,
and gravitational wave emission are relevant for precise pulsar timing,
improving the knowledge of neutron star equation of state, and the search for
continuous gravitational waves with 3-rd generation ground-based and
space-based gravitational wave detectors.",2307.11270v2
2003-08-08,Dynamic Stripes and Resonance in the Superconducting and Normal Phases of YBa2Cu3O6.5 Ortho-II Superconductor,"We describe the relation between spin fluctuations and superconductivity in a
highly-ordered sample of YBaCu3O6.5 using both polarized and unpolarized
neutron inelastic scattering. The spin susceptibility in the superconducting
phase exhibits one-dimensional incommensurate modulations at low-energies,
consistent with hydrodynamic stripes. With increasing energy the susceptibility
curves upward to a commensurate, intense, well-defined and asymmetric resonance
at 33 meV with a precipitous high-energy cutoff. In the normal phase, which we
show is gapless, the resonance remains surprisingly strong and persists clearly
in Q scans and energy scans. Its similar asymmetric spectral form above Tc=59 K
suggests that incoherent superconducting pairing fluctuations are present in
the normal state. On cooling, the resonance and the stripe modulations grow in
well above Tc below a temperature that is comparable to the pseudogap
temperature where suppression occurs in local and low-momentum properties. The
spectral weight that accrues to the resonance is largely acquired by transfer
from suppressed low-energy fluctuations. We find the resonance to be
isotropically polarized, consistent with a triplet carrying ~2.6% of the total
spectral weight of the Cu spins in the planes.",0308168v2
2011-08-01,"Effect of nodes, ellipticity and impurities on the spin resonance in Iron-based superconductors","We analyze doping dependence of the spin resonance of an s+- superconductor
and its sensitivity to the ellipticity of electron pockets, to magnetic and
non-magnetic impurities, and to the angle dependence of the superconducting gap
along electron Fermi surfaces. We show that the maximum intensity of the
resonance shifts from commensurate to incommensurate momentum above some
critical doping which decreases with increasing ellipticity. Angle dependence
of the gap and particularly the presence of accidental nodes lowers the overall
intensity of the resonance peak and shifts its position towards the onset of
the particle-hole continuum. Still, however, the resonance remains a true
\delta-function in the clean limit. When non-magnetic or magnetic impurities
are present, the resonance broadens and its position shifts. The shift depends
on the type of impurities and on the ratio of intraband and interband
scattering components. The ratio Omega_{res}/T_c increases almost linearly with
the strength of the interband impurity scattering, in agreement with the
experimental data. We also compare spin response of s+- and s++
superconductors. We show that there is no resonance for s++ gap, even when
there is a finite mismatch between electron and hole Fermi surfaces shifted by
the antiferromagnetic momentum.",1108.0266v1
2014-03-18,Dynamically-generated baryon resonances with heavy flavor,"We study baryon resonances with heavy flavor in a molecular approach, thus as
dynamically generated by meson-baryon scattering. This is accomplished by using
a unitary coupled-channel model taking, as bare interaction, the extension to
four flavors and spin symmetry of the Weinberg-Tomozawa interaction potential.
A special attention is paid to the inclusion of heavy-quark spin symmetry and
to the studies of the generated baryon resonances which complete the
heavy-quark spin multiplets. We reproduce few charmed and strange baryon
resonances found experimentally, that is, \Lambda_c(2595), \Lambda_c(2625),
\Xi_c(2790), \Xi_c(2815), and make predictions for more states. The
bottom-flavored \Lambda_b(5912) and \Lambda_b(5920) states, found by the LHCb
collaboration, are also obtained by our model, thus these resonances can be
interpreted as molecular states. We also study \Xi_b resonances, which belong
to the same SU(3) x HQSS multiplets as the observed \Lambda_b particles.
Finally we analyze hidden-charm baryon resonances. In this sector, we predict
seven N-like and five \Delta-like states with masses around 4 GeV, most of them
as bound states, and compare them with predictions from other models. The
predicted states can be searched for in future experiments that involve studies
of heavy-flavor physics, e.g. PANDA/FAIR, where charm physics will be analyzed.",1403.4515v1
2015-01-24,"A method for accurate electron-atom resonances: The complex-scaled multiconfigurational spin-tensor electron propagator method for the $^2P\, \mbox{Be}^{-}$ shape resonance problem","We propose and develop the complex scaled multiconfigurational spin-tensor
electron propagator (CMCSTEP) technique for theoretical determination of
resonance parameters with electron-atom/molecule systems including open-shell
and highly correlated atoms and molecules. The multiconfigurational spin-tensor
electron propagator method (MCSTEP) developed and implemented by Yeager his
coworkers in real space gives very accurate and reliable ionization potentials
and attachment energies. The CMCSTEP method uses a complex scaled
multiconfigurational self-consistent field (CMCSCF) state as an initial state
along with a dilated Hamiltonian where all of the electronic coordinates are
scaled by a complex factor. CMCSCF was developed and applied successfully to
resonance problems earlier. We apply the CMCSTEP method to get $^2
P\,\mbox{Be}^{-}$ shape resonance parameters using $14s11p5d$, $14s14p2d$, and
$14s14p5d$ basis sets with a $2s2p3d$\,CAS. The obtained value of the resonance
parameters are compared to previous results. This is the first time CMCSTEP has
been developed and used for a resonance problem. It will be among the most
accurate and reliable techniques. Vertical ionization potentials and attachment
energies in real space are typically within $\pm 0.2\,eV$ or better of
excellent experiments and full configuration interaction calculations with a
good basis set. We expect the same sort of agreement in complex space.",1501.05987v2
2015-02-05,Contribution to the study of the resonant rotation in the Solar System,"This HDR-thesis is devoted to the study of the rotation of the natural
satellites of the giant planets and of Mercury. These bodies have a resonant
rotation. Most of the natural satellites rotate synchronously, showing the same
hemisphere to their parent planet (1:1 spin-orbit resonance). The case of
Mercury is unique since its spin rate is exactly 1.5 its mean motion (3:2
spin-orbit resonance). These two configurations are dynamical equilibria,
reached after damping of the initial rotation of the relevant bodies. Thus, the
rotation quantities are a signature of the interior, in particular of a
putative global ocean. This manuscript divides into 3 parts. The first part is
devoted to the synchronous resonance. It presents different models of rotation
from a fully rigid body to a one with a global subsurfacic ocean. We always
consider all the degrees of freedom simultaneously, using analytical and
numerical resolutions. These models are applied on Titan, Callisto, Janus,
Epimetheus, Mimas, Hyperion, and Io. The second part presents the resonant
rotation of Mercury, target of the two space missions MESSENGER and
BepiColombo. We reveal in particular how it got trapped into its 3:2 resonance.
The final part presents an algorithm I have elaborated to tackle the rotational
problems.",1502.01472v1
2021-01-28,Universal field dependence of magnetic resonance near zero frequency,"Magnetic resonance is a widely-established phenomenon that probes magnetic
properties such as magnetic damping and anisotropy. Even though the typical
resonance frequency of a magnet ranges from gigahertz to terahertz, experiments
also report the resonance near zero frequency in a large class of magnets. Here
we revisit this phenomenon by analyzing the symmetry of the system and find
that the resonance frequency ($\omega$) follows a universal power law $\omega
\varpropto |H-H_c|^p$, where $H_c$ is the critical field at which the resonance
frequency is zero. When the magnet preserves the rotational symmetry around the
external field ($H$), $p = 1$. Otherwise, $p=1/2$. The magnon excitations are
gapped above $H_c$, gapless at $H_c$ and gapped again below $H_c$. The zero
frequency is often accompanied by a reorientation transition in the
magnetization. For the case that $p=1/2$, this transition is described by a
Landau theory for second-order phase transitions. We further show that the spin
current driven by thermal gradient and spin-orbit effects can be significantly
enhanced when the resonance frequency is close to zero, which can be measured
electrically by converting the spin current into electric signals. This may
provide an experimentally accessible way to characterize the critical field.
Our findings provide a unified understanding of the magnetization dynamics near
the critical field, and may, furthermore, inspire the study of magnon transport
near magnetic transitions.",2101.12292v1
2021-05-08,Coupling microwave photons to topological spin-textures in Cu$_2$OSeO$_3$,"Topologically protected nanoscale spin textures, known as magnetic skyrmions,
possess particle-like properties and feature emergent magnetism effects. In
bulk cubic heli-magnets, distinct skyrmion resonant modes are already
identified using a technique like ferromagnetic resonance in spintronics.
However, direct light-matter coupling between microwave photons and skyrmion
resonance modes has not been demonstrated yet. Utilising two distinct cavity
systems, we realise to observe a direct interaction between the cavity resonant
mode and two resonant skyrmion modes, the counter-clockwise gyration and
breathing modes, in bulk Cu$_2$OSeO$_3$. For both resonant modes, we find the
largest coupling strength at 57 K indicated by an enhancement of the cavity
linewidth at the degeneracy point. We study the effective coupling strength as
a function of temperature within the expected skyrmion phase. We attribute the
maximum in effective coupling strength to the presence of a large number of
skyrmions, and correspondingly to a completely stable skyrmion lattice. Our
experimental findings indicate that the coupling between photons and resonant
modes of magnetic skyrmions depends on the relative density of these
topological particles instead of the pure spin number in the system.",2105.03719v1
2009-05-04,On the nature of kink MHD waves in magnetic flux tubes,"Magnetohydrodynamic (MHD) waves are often reported in the solar atmosphere
and usually classified as slow, fast, or Alfv\'en. The possibility that these
waves have mixed properties is often ignored. The goal of this work is to study
and determine the nature of MHD kink waves. This is done by calculating the
frequency, the damping rate and the eigenfunctions of MHD kink waves for three
widely different MHD waves cases: a compressible pressure-less plasma, an
incompressible plasma and a compressible plasma with non-zero plasma pressure
which allows for MHD radiation. In all three cases the frequency and the
damping rate are for practical purposes the same as they differ at most by
terms proportional to $(k_z R)^2$. In the magnetic flux tube the kink waves are
in all three cases, to a high degree of accuracy incompressible waves with
negligible pressure perturbations and with mainly horizontal motions. The main
restoring force of kink waves in the magnetised flux tube is the magnetic
tension force. The total pressure gradient force cannot be neglected except
when the frequency of the kink wave is equal or slightly differs from the local
Alfv\'{e}n frequency, i.e. in the resonant layer. Kink waves are very robust
and do not care about the details of the MHD wave environment. The adjective
fast is not the correct adjective to characterise kink waves. If an adjective
is to be used it should be Alfv\'{e}nic. However, it is better to realize that
kink waves have mixed properties and cannot be put in one single box.",0905.0425v1
2011-03-10,Compressive high-frequency waves riding on an Alfvén/ion-cyclotron wave in a multi-fluid plasma,"In this paper, we study the weakly-compressive high-frequency plasma waves
which are superposed on a large-amplitude Alfv\'en wave in a multi-fluid plasma
consisting of protons, electrons, and alpha particles. For these waves, the
plasma environment is inhomogenous due to the presence of the low-frequency
Alfv\'en wave with a large amplitude, a situation that may apply to space
plasmas such as the solar corona and solar wind. The dispersion relation of the
plasma waves is determined from a linear stability analysis using a new
eigenvalue method that is employed to solve the set of differential wave
equations which describe the propagation of plasma waves along the direction of
the constant component of the Alfv\'en wave magnetic field. This approach also
allows one to consider weak compressive effects. In the presence of the
background Alfv\'en wave, the dispersion branches obtained differ significantly
from the situation of a uniform plasma. Due to compressibility, acoustic waves
are excited and couplings between various modes occur, and even an instability
of the compressive mode. In a kinetic treatment, these plasma waves would be
natural candidates for Landau-resonant wave-particle interactions, and may thus
via their damping lead to particle heating.",1103.2029v3
2017-04-07,Growth of Stokes Waves Induced by Wind on a Viscous Liquid of Infinite Depth,"The original investigation of Lamb (1932, {\S}349) for the effect of
viscosity on monochromatic surface waves is extended to account for
second-order Stokes surface waves on deep water in the presence of surface
tension. This extension is used to evaluate interfacial impedance for Stokes
waves under the assumption that the waves are growing and hence the surface
waves are unsteady. Thus, the previous investigation of Sajjadi et al. (2014)
is further explored in that (i) the surface wave is unsteady and nonlinear, and
(ii) the effect of the water viscosity, which affects surface stresses, is
taken into account. The determination of energy-transfer parameter, from wind
to waves, are calculated through a turbulence closure model but it is shown the
contribution due to turbulent shear flow is some 20% lower than that obtained
previously. A derivation leading to an expression for the closed streamlines
(Kelvin cat-eyes), which arise in the vicinity of the critical height, is found
for unsteady surface waves. From this expression it is deduced that as waves
grow or decay, the cats-eye are no longer symmetrical. Also investigated is the
energy transfer from wind to short Stokes waves through the viscous Reynolds
stresses in the immediate neighborhood of the water surface. It is shown that
the resonance between the Tollmien-Schlichting waves for a given turbulent wind
velocity profile and the free-surface Stokes waves give rise to an additional
contribution to the growth of nonlinear surface waves.",1704.02353v1
2012-03-29,Crossover from spin accumulation into interface states to spin injection in the germanium conduction band,"Electrical spin injection into semiconductors paves the way for exploring new
phenomena in the area of spin physics and new generations of spintronic
devices. However the exact role of interface states in spin injection mechanism
from a magnetic tunnel junction into a semiconductor is still under debate. In
this letter, we demonstrate a clear transition from spin accumulation into
interface states to spin injection in the conduction band of $n$-Ge. We observe
spin signal amplification at low temperature due to spin accumulation into
interface states followed by a clear transition towards spin injection in the
conduction band from 200 K up to room temperature. In this regime, the spin
signal is reduced down to a value compatible with spin diffusion model. More
interestingly, we demonstrate in this regime a significant modulation of the
spin signal by spin pumping generated by ferromagnetic resonance and also by
applying a back-gate voltage which are clear manifestations of spin current and
accumulation in the germanium conduction band.",1203.6491v2
2019-04-02,Spin pumping and spin torque in interfacial tailored Co2FeAl/\b{eta}-Ta layers,"The Heusler ferromagnetic (FM) compound Co2FeAl interfaced with a high-spin
orbit coupling non-magnetic (NM) layer is a promising candidate for energy
efficient spin logic circuits. The circuit potential depends on the strength of
angular momentum transfer across the FM/NM interface; hence, requiring low spin
memory loss and high spin-mixing conductance. To highlight this issue, spin
pumping and spin-transfer torque ferromagnetic resonance measurements have been
performed on Co_2FeAl/\beta-Ta heterostructures tailored with Cu interfacial
layers. The interface tailored structure yields an enhancement of the effective
spin-mixing conductance. The interface transparency and spin memory loss
corrected values of the spin-mixing conductance, spin Hall angle and spin
diffusion length are found to be 3.40 \pm 0.01 \times 10^{19} m^{-2}, 0.029 \pm
0.003, and 2.3 \pm 0.5 nm, respectively. Furthermore, a high current modulation
of the effective damping of around 2.1 % has been achieved at an applied
current density of 1 \times 10^9 A/m^2 , which clearly indicates the potential
of using this heterostructure for energy efficient control in spin devices",1904.01506v3
2023-06-29,Control of an environmental spin defect beyond the coherence limit of a central spin,"Electronic spin defects in the environment of an optically-active spin can be
used to increase the size and hence the performance of solid-state quantum
registers, especially for applications in quantum metrology and quantum
communication. Previous works on multi-qubit electronic-spin registers in the
environment of a Nitrogen-Vacancy (NV) center in diamond have only included
spins directly coupled to the NV. As this direct coupling is limited by the
central spin coherence time, it significantly restricts the register's maximum
attainable size. To address this problem, we present a scalable approach to
increase the size of electronic-spin registers. Our approach exploits a
weakly-coupled probe spin together with double-resonance control sequences to
mediate the transfer of spin polarization between the central NV spin and an
environmental spin that is not directly coupled to it. We experimentally
realize this approach to demonstrate the detection and coherent control of an
unknown electronic spin outside the coherence limit of a central NV. Our work
paves the way for engineering larger quantum spin registers with the potential
to advance nanoscale sensing, enable correlated noise spectroscopy for error
correction, and facilitate the realization of spin-chain quantum wires for
quantum communication.",2306.17155v3
1997-10-02,Resonant Gravitational Wave Amplification - Axion and Inflaton,"We demonstrate the parametric amplification of the stochastic gravitational
wave background during inflationary reheating and during axion/moduli
oscillations. This amplification enhances the detectability of the
string/inflationary gravity wave signal, leaving a finger-print on the spectrum
which might be found with future gravitational wave detectors.",9710036v1
1999-10-04,Excitation of Alfven Waves and Pulsar Radio Emission,"We analyze mechanisms of the excitation of Alfv\'{e}n wave in pulsar
magnetospheres as a possible source of pulsar radio emission generation. We
find that Cherenkov excitation of obliquely propagating Alfv\'{e}n waves is
inefficient, while excitation at the anomalous cyclotron resonance by the
particles from the primary beam and from the tail of the bulk distribution
function may have a considerable growth rate. The cyclotron instability on
Alfv\'{e}n waves occurs in the kinetic regime still not very closed to the
star: $r \geq 50 R_{NS}$. We also discuss various mechanisms of conversion of
Alfv\'{e}n waves into escaping radiation. Unfortunately, no decisive conclusion
about the effectiveness of such conversion can be made.",9910068v1
2000-01-08,Nature of microstructure in pulsar radio emission,"We present a model for microstructure in pulsar radio emission. We propose
that micropulses result from the alteration of the radio wave generation region
by nearly transverse drift waves propagating across the pulsar magnetic field
and encircling the bundle of the open magnetic field lines. It is demonstrated
that such waves can modify significantly curvature of these dipolar field
lines. This in turn affects strongly fulfillment of the resonance conditions
necessary for the excitation of radio waves. The time-scale of micropulses is
therefore determined by the wavelength of drift waves. Main features of the
microstructure are naturally explained in the frame of this model.",0001132v1
1998-12-28,Investigation of Joint Effect of Two Mechanisms of Probe Wave Anomalous Attenuation,"Two mechanisms of anomalous attenuation of probe waves in the experiments of
ionosphere modification are discussed in the paper. The first mechanism is the
well-known conversion of ordinary wave into plasma waves due to scattering from
random irregularities in the upper-hybrid resonance region. The second
mechanism is the multiple scattering. This mechanism is responsible for
anomalous attenuation of extraordinary wave have been observed in several
experiments. Investigation of joint effect of both mechanisms gives additional
possibilities for diagnostics of artificial irregularities.",9812047v1
2005-09-22,Laboratory observation of a nonlinear interaction between shear Alfvén waves,"An experimental investigation of nonlinear interactions between shear
Alfv\'{e}n waves in a laboratory plasma is presented. Two Alfv\'{e}n waves,
generated by a resonant cavity, are observed to beat together, driving a low
frequency nonlinear psuedo-mode at the beat frequency. The psuedo-mode then
scatters the Alfv\'{e}n waves, generating a series of sidebands. The observed
interaction is very strong, with the normalized amplitude of the driven
psuedo-mode comparable to the normalized magnetic field amplitude ($\delta
B/B$) of the interacting Alfv\'{e}n waves.",0509180v1
2005-11-01,Observation of Brewster's effect for transverse-electric electromagnetic waves in metamaterials: Experiment and theory,"We have experimentally realized Brewster's effect for transverse-electric
waves with metamaterials. In dielectric media, Brewster's no-reflection effect
arises only for transverse-magnetic waves. However, it has been theoretically
predicted that Brewster's effect arises for TE waves under the condition that
the relative permeability r is not equal to unity. We have designed an array of
split-ring resonators as a metamaterial with mu_r 1 using a finite-difference
time-domain method. The reflection measurements were carried out in a 3-GHz
region and the disappearance of reflected waves at a particular incident angle
was confirmed.",0511005v2
2006-02-28,Enhanced Transmission of Light and Matter through Nanoapertures without Assistance of Surface Waves,"Subwavelength aperture arrays in thin metal films enable enhanced
transmission of light and matter waves [for example, see T.W. Ebbesen et al.,
Nature (London) 391, 667 (1998) and E. Moreno et al., Phys. Rev. Lett. 95,
170406 (2005)]. The phenomenon relies on resonant excitation of the surface
electron or matter waves. We show another mechanism that provides a great
transmission enhancement not by coupling to the surface waves but by the
interference of diffracted evanescent waves in the far-field zone. Verification
of the mechanism is presented by comparison with recently published data.",0602190v2
2008-03-12,Single- and Multichannel Wave Bending,"Recently, we have discovered a new concept of permanent wave resonance with
potential spatial oscillations. This means the constant wave swinging frequency
on the whole energy intervals of spectral forbidden zones destroying physical
solutions and deepening the theory of waves in periodic potentials. It also
shows the other side of strengthening the fundamentally important magic nuclear
structures. A new language of wave bending will be presented to enrich our
quantum intuition, e.g., the paradoxical effective attraction of barriers and
repulsion of wells in multichannel systems.",0803.1767v1
2008-03-20,Response of a ferrofluid to traveling-stripe forcing,"We observe the dynamics of waves propagating on the surface of a ferrofluid
under the influence of a spatially and temporarily modulated field. In
particular, we excite plane waves by a travelling lamellar modulation of the
magnetization. By this external driving both the wavelength and the propagation
velocity of the waves can be controlled. The amplitude of the excited waves
exhibits a resonance phenomenon similar to that of a forced harmonic
oscillator. Its analysis reveals the dispersion relation of the free surface
waves, from which the critical magnetic field for the onset of the Rosensweig
instability can be extrapolated.",0803.3038v1
2008-10-07,Water-wave gap solitons: An approximate theory and accurate numerical experiments,"It is demonstrated that a standard coupled-mode theory can successfully
describe weakly-nonlinear gravity water waves in Bragg resonance with a
periodic one-dimensional topography. Analytical solutions for gap solitons
provided by this theory are in a reasonable agreement with accurate numerical
simulations of exact equations of motion for ideal planar potential
free-surface flows, even for strongly nonlinear waves. In numerical
experiments, self-localized groups of nearly standing water waves can exist up
to hundreds of wave periods. Generalizations of the model to the
three-dimensional case are also derived.",0810.1125v2
2009-12-04,Experimental and numerical studies of terahertz surface waves on a thin metamaterial film,"We present experimental and numerical studies of localized terahertz surface
waves on a subwavelength-thick metamaterial film consisting of in-plane
split-ring resonators. A simple and intuitive model is derived that describes
the propagation of surface waves as guided modes in a waveguide filled with a
Lorentz-like medium. The effective medium model allows to deduce the dispersion
relation of the surface waves in excellent agreement with the numerical data
obtained from 3-D full-wave calculations. Both the accuracy of the analytical
model and the numerical calculations are confirmed by spectroscopic terahertz
time domain measurements.",0912.0800v1
2009-12-15,Acoustic excitation of superharmonic capillary waves on a meniscus in a planar micro-geometry,"The effects of ultrasound on the dynamics of an air-water meniscus in a
planar micro-geometry are investigated experimentally. The sonicated meniscus
exhibits harmonic traveling waves or standing waves, the latter corresponding
to a higher ultrasound level. Standing capillary waves with subharmonic and
superharmonic frequencies are also observed, and are explained in the framework
of parametric resonance theory, using the Mathieu equation.",0912.2903v1
2010-01-06,Plasma waves reflection from a boundary with specular accommodative boundary conditions,"In the present work the linearized problem of plasma wave reflection from a
boundary of a half--space is solved analytically. Specular accommodative
conditions of plasma wave reflection from plasma boundary are taken into
consideration. Wave reflectance is found as function of the given parameters of
the problem, and its dependence on the normal electron momentum accommodation
coefficient is shown by the authors. The case of resonance when the frequency
of self-consistent electric field oscillations is close to the proper
(Langmuir) plasma oscillations frequency, namely, the case of long wave limit
is analyzed. Refs. 17. Figs. 6.",1001.0845v1
2011-07-14,Ponderomotive forces and wave dispersion: two sides of the same coin,"Presented here is a general view on adiabatic and resonant wave-particle
interactions leading to a uniform description of nonlinear ponderomotive
effects in very different environments, from low-temperature plasmas to
relativistic plasmas or even atoms in laser light. Treating the wave-particle
interaction as a classical mode-coupling problem, this theory shows the
inherent connection between the ponderomotive forces and the properties of
waves causing those forces. The adiabatic Lagrangians are derived for single
particles and nonlinear waves, possibly carrying trapped particles, and yield
both the dynamic equations and the nonlinear dispersion relations in the
general case.",1107.2852v1
2012-11-30,Atom lens without chromatic aberrations,"We propose a lens for atoms with reduced chromatic aberrations and calculate
its focal length and spot size. In our scheme a two-level atom interacts with a
near-resonant standing light wave formed by two running waves of slightly
different wave vectors, and a far-detuned running wave propagating
perpendicular to the standing wave. We show that within the Raman-Nath
approximation and for an adiabatically slow atom-light interaction, the phase
acquired by the atom is independent of the incident atomic velocity.",1211.7220v3
2014-01-01,Unveiling Magnetic Dipole Radiation in Phase-Reversal Leaky-Wave Antennas,"The radiation principle of travelling-wave type phase-reversal antennas is
explained in details, unveiling the presence of magnetic-dipole radiation in
addition to well-known electric dipole radiation. It is point out that such
magnetic dipole radiation is specific to the case of traveling-wave
phase-reversal antennas whereas only electric-dipole radiation exists in
resonant-type phase-reversal antennas. It is shown that a phase-reversal
travelling-wave antenna alternately operates as an array of magnetic dipoles
and an array of electric-dipoles during a time-harmonic period. This radiation
mechanism is confirmed through both full-wave and experimental results.",1401.0242v1
2015-08-08,Implementation of electromagnetically induced transparency in a metamaterial controlled with auxiliary waves,"We propose a metamaterial to realize true electromagnetically induced
transparency (EIT), where the incidence of an auxiliary electromagnetic wave
called the control wave induces transparency for a probe wave. The analogy to
the original EIT effect in an atomic medium is shown through analytical and
numerical calculations derived from a circuit model for the metamaterial. We
performed experiments to demonstrate the EIT effect of the metamaterial in the
microwave region. The width and position of the transparent region can be
controlled by the power and frequency of the control wave. We also observed
asymmetric transmission spectra unique to the Fano resonance.",1508.01889v2
2015-12-07,Wave-particle interactions in the outer radiation belts,"Data from the Van Allen Probes have provided the first extensive evidence of
non-linear (as opposed to quasi-linear) wave-particle interactions in space
with the associated rapid (fraction of a bounce period) electron acceleration
to hundreds of keV by Landau resonance in the parallel electric fields of time
domain structures (TDS) and very oblique chorus waves. The experimental
evidence, simulations, and theories of these processes are discussed. {\bf Key
words:} the radiation belts, wave-particle interaction, plasma waves and
instabilities",1512.01863v1
2016-01-31,Interaction of modulated gravity water waves of finite depth,"We consider the capillary-gravity water-waves problem of finite depth with a
flat bottom of one or two horizontal dimensions. We derive the modulation
equations of leading and next-to-leading order in the hyperbolic scaling for
three weakly amplitude-modulated plane-wave solutions of the linearized problem
in the absence of quadratic and cubic resonances. We fully justify the derived
system of macroscopic equations in the case of pure gravity waves, i.e. in the
case of zero surface tension, employing the stability of the water-waves
problem on the time-scale $O(1/\ep)$ obtained by Alvarez-Samaniego and Lannes.",1602.00255v1
2017-01-06,Parametric decay of plasma waves near the upper-hybrid resonance,"An intense X wave propagating perpendicularly to dc magnetic field is
unstable with respect to a parametric decay into an electron Bernstein wave and
a lower-hybrid wave. A modified theory of this effect is proposed that extends
to the high-intensity regime, where the instability rate $\gamma$ ceases to be
a linear function of the incident-wave amplitude. An explicit formula for
$\gamma$ is derived and expressed in terms of cold-plasma parameters. Theory
predictions are in reasonable agreement with the results of the
particle-in-cell simulations presented in a separate publication.",1701.01690v1
2021-09-24,An alternative proof of modulation instability of Stokes waves in deep water,"We generalize the periodic Evans function approach recently used to study the
spectral stability of Stokes wave and gravity-capillary (including Wilton
ripples) in water of finite depth to study spectral stability of Stokes waves
in water of infinite depth. We prove waves of sufficiently small amplitude are
always low-frequency unstable regardless of the wave number and gravity, giving
an alternative proof for the Benjamin-Feir modulational instability in the
infinite depth case. Here, the first proof for the infinite depth case is
recently obtained by Nguyen and Strauss. We also study the spectral stability
at non-zero resonant frequencies and find no additional instability.",2109.12101v2
2022-01-14,RayleighBloch waves above the cut-off,"Extensions of Rayleigh-Bloch waves above the cut-off frequency are studied
via the discrete spectrum of a transfer operator for a generalised channel
containing a single cylinder. Their wavenumbers are shown to become
complex-valued and an additional pair of wavenumbers to appear. For small to
intermediate radius values, the extended Rayleigh-Bloch waves are shown connect
the Neumann and Dirichlet trapped modes, then embed in the continuous spectrum.
Rayleigh-Bloch waves vanish as frequency increases but reappear at high
frequencies for small and large cylinders. The existence and properties of the
Rayleigh-Bloch waves are connected with finite-array resonances.",2201.05295v1
2022-03-03,The dispersion and propagation of topological Langmuir-cyclotron waves in cold magnetized plasmas,"Topological Langmuir-Cyclotron Wave (TLCW) is a recently identified
topological surface excitation in magnetized plasmas. We show that TLCW
originates from the topological phase transition at the Langmuir wave-cyclotron
wave resonance. By isofrequency surface analysis and 2D and 3D time-dependent
simulations, we demonstrate that the TLCW can propagate robustly along complex
phase transition interfaces in a unidirectional manner and without scattering.
Because of these desirable features, the TLCW could be explored as an effective
mechanism to drive current and flow in magnetized plasmas. The analysis also
establishes a close connection between the newly instituted topological phase
classification of plasmas and the classical CMA diagram of plasma waves.",2203.01915v2
2023-06-29,Stochastic gravitational wave background from early dark energy,"We study the production of stochastic gravitational wave background from
early dark energy (EDE) model. It is caused by resonant amplification of scalar
field fluctuations, which easily takes place for typical EDE potential based on
the string axion or $\alpha$-attractor model. The resultant spectrum of
gravitational wave background is computed by performing 3D lattice simulations.
We show that, specifically in some class of generalized $\alpha$-attractor EDE
model, a significant amount of gravitational waves can be produced via
tachyonic instability with a peak around femto-Hz frequency range. Models
predicting such gravitational waves can be constrained by the cosmic microwave
background observations.",2306.16896v1
2024-03-19,Simulation of the Wave Turbulence of a Liquid Surface Using the Dynamic Conformal Transformation Method,"The dynamic conformal transformation method has been generalized for the
first time to numerically simulate the capillary wave turbulence of a liquid
surface in the plane symmetric anisotropic geometry. The model is strongly
nonlinear and involves effects of surface tension, as well as energy
dissipation and pumping. Simulation results have shown that the system of
nonlinear capillary waves can pass to the quasistationary chaotic motion regime
(wave turbulence). The calculated exponents of spectra do not coincide with
those for the classical Zakharov-Filonenko spectrum for isotropic capillary
turbulence but are in good agreement with the estimate obtained under the
assumption of the dominant effect of five-wave resonant interactions.",2403.12592v1
2012-04-01,Magnetostatic spin waves and magnetic-wave chaos in ferromagnetic films. I. Theory of magnetostatic waves in plates under arbitrary anisotropy and external fields,"General phenomenological theory of magnetic spin waves in ferromagnetic media
is originally reformulated and applied to analysis of magnetostatic waves in
films and plates with arbitrary nisotropy under arbitrary external field. Exact
expressions are derived for propagator of linear waves between antennae
(inductors) and mutual impedances of antennae, and exact unified dispersion
equation is obtained which describes all types of magnetostatic wave
eigen-modes. Characteristic frequencies (spectra) and some other important
properties of main modes are analytically considered and graphically
illustrated. Besides, several aspects of non-linear excitations and
magnetic-wave chaos are discussed, including two-dimensional ""non-linear
Schrodinger equations"" for magnetostatic wave packets and envelope solitons.",1204.0200v1
1998-01-15,Obervation of non-linear stationary spin waves in superfluid 3He-B,"Due to its broken spin and orbit rotation symmetries, superfluid $^3$He plays
a unique role for testing rotational quantum properties on a macroscopic scale.
In this system the orbital momentum forms textures that provide an effective
potential well for the creation of stationary spin waves. In the limit of the
lowest temperatures presently attainable, we observe by NMR techniques a
profound change in the spin dynamics. The NMR line shape becomes asymmetric,
strongly hysteretic and displays substantial frequency shifts. This behavior,
quantitatively described by an anharmonic oscillator model, indicates that the
parameters of the potential well depend on the spin waves amplitude, and
therefore that the orbital motion is not damped in this new regime, not
considered by the standard Leggett-Takagi theory. This regime of non-linear
stationary spin waves is shown to give rise to the pulsed NMR ""Persistent
Signals"" reported recently.",9801159v1
1999-09-14,Spin Wave Theory of Double Exchange Magnets,"An isotropic half-metallic double exchange magnet with a direct superexchange
coupling between the localized spins is studied within the spin-wave (1/S)
expansion. The momentum dependence of the spin wave spectrum (including quantum
corrections) in the ferromagnetic phase at T=0 is investigated. Based on the
calculated spin wave spectrum of the canted state, it is shown that as long as
the external magnetic field is not too strong, the double exchange --
superexchange competition does not result in a stabilization of a
two-sublattice canted spin ordering.",9909213v3
2005-07-28,Theory of transverse spin dynamics in a polarized Fermi liquid and an itinerant ferromagnet,"The linear equations for transverse spin dynamics in a weakly polarized
degenerate Fermi liquid with arbitrary relationship between temperature and
polarization are derived from Landau-Silin phenomenological kinetic equation
with general form of two-particle collision integral. Unlike the previous
treatment where Fermi velocity and density of states have been taken as
constants independent of polarization here we made derivation free from this
assumption. The obtained equations are applicable for description of spin
dynamics in paramagnetic Fermi liquid with finite polarization as well in an
itinerant ferromagnet. In both cases transverse spin wave frequency is found to
be proportional to the square of the wave vector with complex constant of
proportionality (diffusion coefficient) such that the damping has a finite
value at T=0. The polarization dependence of the diffusion coefficient is found
to be different for a polarized Fermi liquid and for an itinerant ferromagnet.
These conclusions are confirmed by derivation of transverse spin wave
dispersion law in frame of field theoretical methods from the integral equation
for the vortex function. It is shown that similar derivation taking into
consideration the divergency of static transverse susceptibility also leads to
the same attenuating spin wave spectrum.",0507675v1
2005-08-19,Spin-waves in antiferromagnetic single crystal LiFePO$_4$,"Spin-wave dispersions in the antiferromagnetic state of single crystal
LiFePO$_4$ were determined by inelastic neutron scattering measurements. The
dispersion curves measured from the (010) reflection along both {\it a}$^\ast$
and {\it b}$^\ast$ reciprocal-space directions reflect the anisotropic coupling
of the layered Fe$^{2+}$ (S = 2) spin-system. The spin-wave dispersion curves
were theoretically modeled using linear spin-wave theory by including in the
spin-Hamiltonian in-plane nearest- and next-nearest-neighbor interactions ({\it
J}$_1$ and {\it J}$_2$), inter-plane nearest-neighbor interactions ({\it
J}$_\bot$) and a single-ion anisotropy ({\it D}). A weak (010) magnetic peak
was observed in elastic neutron scattering studies of the same crystal
indicating that the ground state of the staggered iron moments is not along
(010) direction, as previously reported from polycrystalline samples studies,
but slightly rotated away from this axis.",0508480v1
2006-03-10,Magnetic Structure and Spin Waves in the Kagomé Jarosite compound ${\bf KFe_3(SO_4)_2(OH)_6}$,"We present a detailed study of the magnetic structure and spin waves in the
Fe jarosite compound ${\rm KFe_3(SO_4)_2(OH)_6}$ for the most general
Hamiltonian involving one- and two-spin interactions which are allowed by
symmetry. We compare the calculated spin-wave spectrum with the recent neutron
scattering data of Matan {\it et al.} for various model Hamiltonians which
include, in addition to isotropic Heisenberg exchange interactions between
nearest ($J_1$) and next-nearest ($J_2$) neighbors, single ion anisotropy and
Dzyaloshinskii-Moriya (DM) interactions. We concluded that DM interactions are
the dominant anisotropic interaction, which not only fits all the splittings in
the spin-wave spectrum but also reproduces the small canting of the spins out
of the Kagom\'e plane. A brief discussion of how representation theory
restricts the allowed magnetic structure is also given.",0603280v1
2007-01-08,Quantum corrections to the spin-wave spectrum of La$_2$CuO$_4$ in an external magnetic field,"The effects of quantum fluctuations on the magnetic field dependence of the
spin-wave gaps in the lamellar antiferromagnet La$_2$CuO$_4$ are considered.
Nonlinear corrections to the spin-wave spectrum are calculated to leading order
in 1/S, where $S$ is the localized spin. The nearest-neighbor exchange
interactions between the Cu spins as well as the Dzyaloshinskii-Moriya
interactions are taken into account. Using the experimental values of the
components of the $g$-factor tensor, we get a satisfactory agreement with the
experimental results for the field dependence of the gaps by Gozar {\it et al.}
[Phys. Rev. Lett. {\bf 93}, 027001 (2004)], and obtain consistent values of the
in-plane and inter-plane coupling constants. The field dependence of the
dispersion of spin waves propagating perpendicular to the CuO$_2$ planes is
also discussed.",0701143v1
2000-03-16,Fields on the Poincare group: arbitrary spin description and relativistic wave equations,"In this paper, starting from pure group-theoretical point of view, we develop
a regular approach to describing particles with different spins in the
framework of a theory of scalar fields on the Poincare group. Such fields can
be considered as generating functions for conventional spin-tensor fields. The
cases of 2, 3, and 4 dimensions are elaborated in detail. Discrete
transformations $C,P,T$ are defined for the scalar fields as automorphisms of
the Poincare group. Doing a classification of the scalar functions, we obtain
relativistic wave equations for particles with definite spin and mass. There
exist two different types of scalar functions (which describe the same mass and
spin), one related to a finite-dimensional nonunitary representation and
another one related to an infinite-dimensional unitary representation of the
Lorentz subgroup. This allows us to derive both usual finite-component wave
equations for spin-tensor fields and positive energy infinite-component wave
equations.",0003146v2
2008-04-09,Multiferroic materials for spin-based logic devices,"Logical devices based on spin waves offer the potential to avoid dissipation
mechanisms that limit devices based on either the charge or spin of mobile
electrons. Multiferroic magnetoelectrics, which are materials that combine
ferroelectric and magnetic order, allow direct switching of magnetic order and
thence of spin-wave properties using an applied electric field. The intrinsic
coupling between polarization and magnetic moments, generated by strong
electronic correlations in these multiferroic materials, is argued to provide
new approaches to spin-wave injection and spin-wave switching using applied
voltages with no external magnetic field. These effects are shown to arise in a
phenomenological Landau theory of coupled electronic and magnetic orders in
multiferroic BiFeO3, and found to depend subtly on differences between the
crystalline and film states of this material.",0804.1539v1
2009-09-07,Spin excitations in the excitonic spin-density-wave state of the iron pnictides,"Motivated by the iron pnictides, we examine the spin excitations in an
itinerant antiferromagnet where a spin-density wave (SDW) originates from an
excitonic instability of nested electron-like and hole-like Fermi pockets.
Using the random phase approximation (RPA), we derive the Dyson equation for
the transverse susceptibility in the excitonic SDW state. The Dyson equation is
solved for two different two-band models, describing an antiferromagnetic
insulator and metal, respectively. We determine the collective spin-wave
dispersions and also consider the single-particle continua. The results for the
excitonic models are compared with each other and also contrasted with the
well-known SDW state of the Hubbard model. Despite the qualitatively different
SDW states in the two excitonic models, their magnetic response shows many
similarities. We conclude with a discussion of the relevance of the excitonic
SDW scenario to the iron pnictides.",0909.1222v2
2010-01-15,Neutrino emission from spin waves in neutron spin-triplet superfluid,"The linear response of a neutron spin-triplet superfluid onto external weak
axial-vector field is studied for the case of $^{3}P_{2}$ pairing with a
projection of the total angular momentum $m_{j}=0$. The problem is considered
in the BCS approximation discarding Fermi-liquid effects. The anomalous
axial-vector vertices of neutron quasiparticles possess singularities at some
frequencies which specify existence of undamped spin-density waves in the
Cooper condensate. The spin waves are of a low excitation energy and are
kinematically able to decay into neutrino pairs through neutral weak currents.
We evaluate the neutrino emissivity from the spin wave decays in the bulk
neutron superfluid in old neutron stars. This calculation predicts significant
energy losses from within a neutron star at lowest temperatures when all other
mechanisms of neutrino emission are killed by the neutron and proton
superfluidity.",1001.2617v2
2010-01-21,Quantized antiferromagnetic spin waves in the molecular Heisenberg ring CsFe$_8$,"We report on inelastic neutron scattering (INS) measurements on the molecular
spin ring CsFe$_8$, in which eight spin-5/2 Fe(III) ions are coupled by
nearest-neighbor antiferromagnetic Heisenberg interaction. We have recorded INS
data on a non-deuterated powder sample up to high energies at the
time-of-flight spectrometers FOCUS at PSI and MARI at ISIS, which clearly show
the excitation of spin waves in the ring. Due to the small number of spin
sites, the spin-wave dispersion relation is not continuous but quantized.
Furthermore, the system exhibits a gap between the ground state and the first
excited state. We have modeled our data using exact diagonalization of a
Heisenberg-exchange Hamiltonian together with a small single-ion anisotropy
term. Due to the molecule's symmetry, only two parameters $J$ and $D$ are
needed to obtain excellent agreement with the data. The results can be well
described within the framework of the rotational-band model as well as
antiferromagnetic spin-wave theories.",1001.3755v1
2010-02-26,Correlation Effects in the Stochastic Landau-Lifshitz-Gilbert Equation,"We analyze the Landau-Lifshitz-Gilbert equation when the precession motion of
the magnetic moments is additionally subjected to an uniaxial anisotropy and is
driven by a multiplicative coupled stochastic field with a finite correlation
time $\tau$. The mean value for the spin wave components offers that the
spin-wave dispersion relation and its damping is strongly influenced by the
deterministic Gilbert damping parameter $\alpha$, the strength of the
stochastic forces $D$ and its temporal range $\tau$. The spin-spin-correlation
function can be calculated in the low correlation time limit by deriving an
evolution equation for the joint probability function. The stability analysis
enables us to find the phase diagram within the $\alpha-D$ plane for different
values of $\tau$ where damped spin wave solutions are stable. Even for zero
deterministic Gilbert damping the magnons offer a finite lifetime. We detect a
parameter range where the deterministic and the stochastic damping mechanism
are able to compensate each other leading to undamped spin-waves. The onset is
characterized by a critical value of the correlation time. An enhancement of
$\tau$ leads to an increase of the oscillations of the correlation function.",1002.4958v1
2010-08-05,Influence of spin waves on transport through a quantum-dot spin valve,"We study the influence of spin waves on transport through a single-level
quantum dot weakly coupled to ferromagnetic electrodes with noncollinear
magnetizations. Side peaks appear in the differential conductance due to
emission and absorption of spin waves. We, furthermore, investigate the
nonequilibrium magnon distributions generated in the source and drain lead. In
addition, we show how magnon-assisted tunneling can generate a fullly
spin-polarized current without an applied transport voltage. We discuss the
influence of spin waves on the current noise. Finally, we show how the magnonic
contributions to the exchange field can be detected in the finite-frequency
Fano factor.",1008.0948v2
2012-01-30,"Exchange constants and spin waves of the orbital ordered, non-collinear spinel MnV$_2$O$_4$","We study the exchange constants of MnV$_2$O$_4$ using magnetic force theorem
and local spin density approximation of density functional theory supplemented
with a correction due to on-site Hubbard interaction U. We obtain the exchanges
for three different orbital orderings of the Vanadium atoms of the spinel. We
then map the exchange constants to a Heisenberg model with single-ion
anisotropy and solve for the spin-wave excitations in the non-collinear, low
temperature phase of the spinel. The single-ion anisotropy parameters are
obtained from an atomic multiplet exact-diagonalization program, taking into
effect the crystal-field splitting and the spin-orbit coupling. We find good
agreement between the spin waves of one of our orbital ordered setups with
previously reported experimental spin waves as determined by neutron
scattering. We can therefore determine the correct orbital order from various
proposals that exist in the literature.",1201.6375v2
2013-06-28,"The role of orbital order in the stabilization of the $(π,0)$ ordered magnetic state in a minimal two-band model for iron pnictides","Spin wave excitations and stability of the ($\pi,0$) ordered magnetic state
are investigated in a minimal two-band itinerant-electron model for iron
pnictides. Presence of hopping anisotropy generates a strong ferro-orbital
order in the $d_{xz}$ and $d_{yz}$ Fe orbitals. The orbital order sign is as
observed in experiments. The induced ferro-orbital order strongly enhances the
spin wave energy scale and stabilizes the magnetic state by optimizing the
strength of the emergent AF and F spin couplings through optimal band fillings
in the two orbitals. The calculated spin-wave dispersion is in quantitative
agreement with neutron scattering measurements. Finite inter-orbital Hund's
coupling is shown to further enhance the spin wave energies state by coupling
the two magnetic sub-systems. A more realistic two-band model with less hopping
anisotropy is also considered which yields not only the circular hole pockets,
also correct ferro-orbital order and emergent F spin coupling.",1306.6727v2
2013-08-12,Oscillating spin-orbit interaction as a source of spin-polarized wave packets in two-terminal nanoscale devices,"Ballistic transport through nanoscale devices with time-dependent Rashba-type
spin-orbit interaction (SOI) can lead to spin-polarized wave packets that
appear even for completely unpolarized input. The SOI that oscillates in a
finite domain generates density and spin polarization fluctuations that leave
the region as propagating waves. Particularly, spin polarization has space and
time dependence even in regions without SOI. Our results are based on an
analytic solution of the time-dependent Schr\""odinger equation. The relevant
Floquet quasi-energies that are obtained appear in the energy spectrum of both
the transmitted and reflected waves.",1308.2552v2
2014-05-09,Magnetic excitations and anomalous spin wave broadening in multiferroic FeV2O4,"We report on the different roles of two orbital-active Fe$^{2+}$ at the A
site and V$^{3+}$ at the B site in the magnetic excitations and on the
anomalous spin wave broadening in FeV$_{2}$O$_{4}$. FeV$_{2}$O$_{4}$ exhibits
three structural transitions and successive paramagnetic (PM)-collinear
ferrimagnetic (CFI)-noncollinear ferrimagnetic (NCFI) transitions. The
high-temperature tetragonal/PM -orthorhombic/CFI transition is accompanied by
the appearance of an energy gap with a high magnitude in the magnetic
excitations due to strong spin-orbit coupling induced anisotropy at the
Fe$^{2+}$ site. While there is no measurable increase in the energy gap from
the orbital ordering of V$^{3+}$ at the orthorhombic/CFI-tetragonal/NCFI
transition, anomalous spin wave broadening is observed in the orthorhombic/CFI
state due to V$^{3+}$ spin fluctuations at the B site. The spin wave broadening
is also observed at the zone boundary without softening, which is discussed in
terms of magnon-phonon coupling.",1405.2272v2
2015-07-12,On a mechanism of high-temperature superconductivity: Spin-electron acoustic wave as a mechanism for the Cooper pair formation,"We have found the mechanism of the electron Cooper pair formation via the
electron interaction by means of the spin-electron acoustic waves. This
mechanism takes place in metals with rather high spin polarization, like
ferromagnetic, ferrimagnetic and antiferromagnetic materials. The spin-electron
acoustic wave mechanism leads to transition temperatures 100 times higher than
the transition temperature allowed by the electron-phonon interaction.
Therefore, spin-electron acoustic waves give the explanation for the
high-temperature superconductivity. We find that the transition temperature has
strong dependence on the electron concentration and the spin polarization of
the electrons.",1507.03295v2
2018-03-26,Theoretical spin-wave dispersions in the antiferromagnetic phase AF1 of MnWO$_4$ based on the polar atomistic model in P2,"The spin wave dispersions of the low temperature antiferromagnetic phase
(AF1) MnWO$_4$ have been numerically calculated based on the recently reported
non-collinear spin configuration with two different canting angles. A
Heisenberg model with competing magnetic exchange couplings and single-ion
anisotropy terms could properly describe the spin wave excitations, including
the newly observed low-lying energy excitation mode $\omega_2$=0.45 meV
appearing at the magnetic zone centre. The spin wave dispersion and intensities
are highly sensitive to two differently aligned spin-canting sublattices in the
AF1 model. Thus this study reinsures the otherwise hardly provable hidden polar
character in MnWO$_4$.",1803.09475v1
2018-06-18,Nonreciprocal spin waves in a chiral antiferromagnet without the Dzyaloshinskii-Moriya interaction,"Non-reciprocal spin wave can facilitate the realization of spin wave logic
devices. It has been demonstrated that the non-reciprocity can emerge when an
external magnetic field is applied to chiral magnets, of which spin structures
depend crucially on an asymmetric exchange interaction, that is, the
Dzyaloshinskii-Moriya interaction (DMI). Here we demonstrate that the
non-reciprocity can arise even without the DMI. We demonstrate this idea for
the chiral antiferromagnet Ba$_2$NbFe$_3$Si$_2$O$_{14}$, of which DMI is very
small and chiral spin structure arises mainly from the competition between
symmetric exchange interactions. We show that when an external magnetic field
is applied, asymmetric energy gap shift occurs and the spin wave becomes
non-reciprocal from the competition between symmetric exchange interactions and
the external magnetic field.",1806.06517v3
2016-12-03,First-principles investigation of spin wave dispersions in surface-reconstructed Co thin films on W(110),"We computed spin wave dispersions of surface-reconstructed Co films on the
W(110) surface in the adiabatic approximation. The magnetic exchange
interactions are obtained via first-principles electronic structure
calculations using the Korringa-Kohn-Rostoker Green function method. We analyze
the strength and oscillatory behavior of the intralayer and interlayer magnetic
interactions and investigate the resulting spin wave dispersions as a function
of the thickness of Co films. In particular, we highlight and explain the
strong impact of hybridization of the electronic states at the Co-W interface
on the magnetic exchange interactions and on the spin wave dispersions. We
compare our results to recent measurements based on electron energy loss
spectroscopy [E. Michel, H. Ibach, and C.M. Schneider, Phys. Rev. B 92, 024407
(2015)]. Good overall agreement with experimental findings can be obtained by
considering the possible overestimation of the spin splitting, stemming from
the local spin density approximation, and adopting an appropriate correction.",1612.00910v2
2019-04-18,Magnonic Analogue Black/White Hole Horizon in Superfluid $^3$He-B: experiment,"We provide experimental details of the first experiment made in zero
temperature limit ($\sim$ 600\,$\mu$K) studying the magnonic black/white hole
horizon analogue using absolutely pure physical system based on the spin
superfluidity in superfluid $^3$He-B. We show that spin precession waves
propagating on the background of the spin super-currents in a channel between
two Bose-Einstein condensates of magnons in form of homogeneously precessing
domains mimic the properties of the black/white horizon. Once the white hole
horizon is formed and blocks the propagation of the spin-precession waves
between two domains, we observed an amplification effect, i.e. when the energy
of the spin precession waves reflected from the horizon is higher than the
energy of the excited spin precession waves before horizon was formed.
Moreover, the estimated temperature of the spontaneous Hawking radiation in
this model system is about four orders of magnitude lower than the system's
background temperature what makes it a promising tool to study the effect of
spontaneous Hawking radiation.",1904.09183v1
2019-09-10,Anisotropic magnetic excitations of a frustrated bilinear-biquadratic spin model -- Implications for spin waves of detwinned iron pnictides,"Elucidating the nature of spin excitations is important to understanding the
mechanism of superconductivity in the iron pnictides. Motivated by recent
inelastic neutron scattering measurements in the nearly 100% detwinned
BaFe$_{2}$As$_{2}$, we study the spin dynamics of an $S=1$ frustrated
bilinear-biquadratic Heisenberg model in the antiferromagnetic phase with
wavevector $(\pi,0)$. The biquadratic interactions are treated in a dynamical
way using a flavor-wave theory in an $SU(3)$ representation. Besides the magnon
(dipolar) excitations, the biquadratic interactions give rise to quadrupolar
excitations at high energies. We find that the quadrupolar wave significantly
influences, in an energy dependent way, the anisotropy between the spin
excitation spectra along the $(\pi,0)$ and $(0,\pi)$ directions in the wave
vector space. Our theoretical results capture the essential behavior of the
spin dynamics measured in the antiferromagnetic phase of the detwinned
BaFe$_2$As$_2$. More generally, our results underscore the importance of
electron correlation effects for the microscopic physics of the iron pnictides.",1909.04555v2
2020-02-13,Representations of tensor rotations and the geometry of spin 1/2,"Making use of the real sl(2,R) Lie group algebra generating a spin 1/2 Lie
group allows to create an explicitly given Lorentz invariant fermion wave. As
the generators are real valued they can be interpreted as a deformation tensor
in particular as a deformation tensor of space. Therefore, it is possible to
model a heuristic purely geometric representation of spin 1/2 in Minkowski
space. However the bigger surprise is that this wave has the space-time
structure of gravitational waves, which are understood to be spin 2 waves.
Given that the uniqueness of angular momentum representations still holds, the
examination of tensor rotations reveals the existence of different
representations of tensor rotations with a different angular parameter due to
an unaccounted basic symmetry of symmetric tensors, where the spin 1/2
representation is a specific representation of tensor rotations corresponding
to the quantum theoretical approach. The seeming contradiction is fully
resolved and allows in addition to understand the notion of different
representations of spin in tensors, again related to different representations
of the tensor.",2002.05560v1
2021-12-15,Spin Waves and Dirac Magnons in a Honeycomb Lattice Zig-zag Antiferromagnet BaNi2(AsO4)2,"The topological properties of massive and massless fermionic quasiparticles
have been intensively investigated over the past decade in topological
materials without magnetism. Recently, the bosonic analogs of such
quasiparticles arising from spin waves have been reported in the
two-dimensional (2D) honeycomb lattice ferromagnet/antiferromagnet and the 3D
antiferromagnet. Here we use time-of-flight inelastic neutron scattering to
study spin waves of the S = 1 honeycomb lattice antiferromagnet BaNi2(AsO4)2,
which has a zig-zag antiferromagnetic (AF) ground state identical to that of
the Kitaev quantum spin liquid candidate alpha-RuCl3. We determine the magnetic
exchange interactions in the zig-zag AF ordered phase, and show that spin waves
in BaNi2(AsO4)2 have symmetry-protected Dirac points inside the Brillouin zone
boundary. These results provide a microscopic understanding of the zig-zag AF
order and associated Dirac magnons in honeycomb lattice magnets, and are also
important for establishing the magnetic interactions in Kitaev quantum spin
liquid candidates.",2112.07915v1
2022-06-01,Exceptional spin wave dynamics in an antiferromagnetic honeycomb lattice,"We theoretically investigate possible effects of electric current on the spin
wave dynamics for the N\'{e}el-type antiferromagnetic order in a honeycomb
lattice. Based on a general vector decomposition of the spin polarization of
conduction electrons, we find that there can exist reciprocal and nonreciprocal
terms in the current-induced torque acting on the local spins in the system.
Furthermore, we show that the reciprocal terms will cause the spin wave Doppler
effect, while the nonreciprocal terms can induce rich non-Hermitian topological
phenomena in the spin wave dynamics, including exceptional points, bulk Fermi
arc, non-Hermitian skin effect, etc. Our results indicate the capability to
manipulate non-Hermitian magnons in magnetic materials by electric current,
which could be important for both fundamental physics and technology
applications.",2206.00723v1
2019-05-23,Optimal dispersive readout of a spin qubit with a microwave resonator,"Strong coupling of semiconductor spin qubits to superconducting microwave
resonators was recently demonstrated. These breakthroughs pave the way for
quantum information processing that combines the long coherence times of
solid-state spin qubits with the long-distance connectivity, fast control, and
fast high-fidelity quantum-non-demolition readout of existing superconducting
qubit implementations. Here, we theoretically analyze and optimize the
dispersive readout of a single spin in a semiconductor double quantum dot (DQD)
coupled to a microwave resonator via its electric dipole moment. The strong
spin-photon coupling arises from the motion of the electron spin in a local
magnetic field gradient. We calculate the signal-to-noise ratio (SNR) of the
readout accounting for both Purcell spin relaxation and spin relaxation arising
from intrinsic electric noise within the semiconductor. We express the maximum
achievable SNR in terms of the cooperativity associated with these two
dissipation processes. We find that while the cooperativity increases with the
strength of the dipole coupling between the DQD and the resonator, it does not
depend on the strength of the magnetic field gradient. We then optimize the SNR
as a function of experimentally tunable DQD parameters. We identify wide
regions of parameter space where the unwanted backaction of the resonator
photons on the qubit is small. Moreover, we find that the coupling of the
resonator to other DQD transitions can enhance the SNR by at least a factor of
two, a ``straddling'' effect that occurs only at nonzero energy detuning of the
DQD double-well potential. We estimate that with current technology,
single-shot readout fidelities in the range $82-95\%$ can be achieved within a
few $\mu\textrm{s}$ of readout time without requiring the use of Purcell
filters.",1905.09702v2
2023-03-29,Strong coupling between a microwave photon and a singlet-triplet qubit,"Tremendous progress in few-qubit quantum processing has been achieved lately
using superconducting resonators coupled to gate voltage defined quantum dots.
While the strong coupling regime has been demonstrated recently for odd charge
parity flopping mode spin qubits, first attempts towards coupling a resonator
to even charge parity singlet-triplet spin qubits have resulted only in weak
spin-photon coupling strengths. Here, we integrate a zincblende InAs nanowire
double quantum dot with strong spin-orbit interaction in a magnetic-field
resilient, high-quality resonator. In contrast to conventional strategies, the
quantum confinement is achieved using deterministically grown wurtzite tunnel
barriers without resorting to electrical gating. Our experiments on even charge
parity states and at large magnetic fields, allow to identify the relevant spin
states and to measure the spin decoherence rates and spin-photon coupling
strengths. Most importantly, we find an anti-crossing between the resonator
mode in the single photon limit and a singlet-triplet qubit with an electron
spin-photon coupling strength of $g/2\pi=139\pm4$ MHz. Combined with the
resonator decay rate $\kappa/2\pi=19.8\pm0.2$ MHz and the qubit dephasing rate
$\gamma/2\pi=116\pm7$ MHz, our system achieves the strong coupling regime in
which the coherent coupling exceeds qubit and resonator linewidth. These
results pave the way towards large-scale quantum system based on
singlet-triplet qubits.",2303.16825v2
2017-08-21,Experimental Benchmarking of Quantum Control in Zero-Field Nuclear Magnetic Resonance,"Zero-field nuclear magnetic resonance (NMR) provides complementary analysis
modalities to those of high-field NMR and allows for ultra-high-resolution
spectroscopy and measurement of untruncated spin-spin interactions. Unlike for
the high-field case, however, universal quantum control -- the ability to
perform arbitrary unitary operations -- has not been experimentally
demonstrated in zero-field NMR. This is because the Larmor frequency for all
spins is identically zero at zero field, making it challenging to individually
address different spin species. We realize a composite-pulse technique for
arbitrary independent rotations of $^1$H and $^{13}$C spins in a two-spin
system. Quantum-information-inspired randomized benchmarking and state
tomography are used to evaluate the quality of the control. We experimentally
demonstrate single-spin control for $^{13}$C with an average gate fidelity of
$0.9960(2)$ and two-spin control via a controlled-not (CNOT) gate with an
estimated fidelity of $0.99$. The combination of arbitrary single-spin gates
and a CNOT gate is sufficient for universal quantum control of the nuclear spin
system. The realization of complete spin control in zero-field NMR is an
essential step towards applications to quantum simulation,
entangled-state-assisted quantum metrology, and zero-field NMR spectroscopy.",1708.06324v1
2022-12-15,Hamiltonian inference from dynamical excitations in confined quantum magnets,"Quantum-disordered models provide a versatile platform to explore the
emergence of quantum excitations in many-body systems. The engineering of spin
models at the atomic scale with scanning tunneling microscopy and the local
imaging of excitations with electrically driven spin resonance has risen as a
powerful strategy to image spin excitations in finite quantum spin systems.
Here, focusing on $S=1/2$ lattices as realized by Ti in MgO, we show that
dynamical spin excitations provide a robust strategy to infer the nature of the
underlying Hamiltonian. We show that finite-size interference of the dynamical
many-body spin excitations of a generalized long-range Heisenberg model allows
the underlying spin couplings to be inferred. We show that the spatial
distribution of local spin excitations in Ti islands and ladders directly
correlates with the underlying ground state in the thermodynamic limit. Using a
supervised learning algorithm, we demonstrate that the different parameters of
the Hamiltonian can be extracted by providing the spatially and
frequency-dependent local excitations that can be directly measured by
electrically driven spin resonance with scanning tunneling microscopy. Our
results put forward local dynamical excitations in confined quantum spin models
as versatile witnesses of the underlying ground state, providing an
experimentally robust strategy for Hamiltonian inference in complex real spin
models.",2212.07893v3
2023-03-13,Experimental investigation of the effect of topological insulator on the magnetization dynamics of ferromagnetic metal: $BiSbTe_{1.5}Se_{1.5}$ and $Ni_{80}Fe_{20}$ heterostructure,"We have studied ferromagnetic metal/topological insulator bilayer system to
understand magnetization dynamics of ferromagnetic metal (FM) in contact with a
topological insulator (TI). At magnetic resonance condition, the precessing
magnetization in the metallic ferromagnet ($Ni_{80}Fe_{20}$) injects spin
current into the topological insulator ($BiSbTe_{1.5}Se_{1.5}$), a phenomenon
known as spin-pumping. Due to the spin pumping effect, fast relaxation in the
ferromagnet results in the broadening of ferromagnetic resonance linewidth
($\Delta H$). We evaluated the parameters like effective Gilbert damping
coefficient ($\alpha_{eff}$), spin-mixing conductance ($g_{eff}^{\uparrow
\downarrow}$) and spin current density ($j_S^0$) to confirm a successful spin
injection due to spin-pumping into the $BiSbTe_{1.5}Se_{1.5}$ layer. TIs embody
a spin-momentum locked surface state that span the bulk band-gap. It can act
differently to the FM magnetization than the other normal metals. To probe the
effect of topological surface state, a systematic low temperature study is
crucial as surface state of TI dominates at lower temperatures. The exponential
growth of $\Delta H$ for all different thickness combination of FM/TI bilayers
and effective Gilbert damping coefficient ($\alpha_{eff}$) with lowering
temperature confirms the prediction that spin chemical bias generated from
spin-pumping induces surface current in TI due to spin-momentum locking. The
hump-like feature of magnetic anisotropy field ($H_K$)of the bilayer around 60K
suggests that the decrease of interfacial in-plane magnetic anisotropy can
result from exchange coupling between the TI surface state and the local
moments of FM layer.",2303.07025v2
2011-01-12,Scattering by coupled resonating elements in air,"Scattering by (a) a single composite scatterer consisting of a concentric
arrangement of an outer N-slit rigid cylinder and an inner cylinder which is
either rigid or in the form of a thin elastic shell and (b) by a finite
periodic array of these scatterers in air has been investigated analytically
and through laboratory experiments. The composite scatterer forms a system of
coupled resonators and gives rise to multiple low frequency resonances. The
corresponding analytical model employs polar angle dependent boundary
conditions on the surface of the N-slit cylinder. The solution inside the slits
assumes plane waves. It is shown also that in the low-frequency range the
N-slit rigid cylinder can be replaced by an equivalent fluid layer. Further
approximations suggest a simple square root dependence of the resonant
frequencies on the number of slits and this is confirmed by data. The observed
resonant phenomena are associated with Helmholtz-like behaviour of the
resonator for which the radius and width of the openings are much smaller than
the wavelength. The problem of scattering by a finite periodic array of such
coupled resonators in air is solved using multiple scattering techniques. The
resulting model predicts band-gap effects resulting from the resonances of the
individual composite scatterers below the first Bragg frequency . Predictions
and data confirm that use of coupled resonators results in substantial
insertion loss peaks related to the resonances within the concentric
configuration. In addition, for both scattering problems experimental data,
predictions of the analytical approach and predictions of the equivalent fluid
layer approximations are compared in the low-frequency interval.",1101.2332v1
2012-12-12,Shape resonances in multi-condensate granular superconductors formed by networks of nanoscale-striped puddles,"A characteristic feature of a superconductor made of multiple condensates is
the possibility of the shape resonances in superconducting gaps. Shape
resonances belong to class of Fano resonances in configuration interaction
between open and closed scattering channels. The Shape resonances arise because
of the exchange interaction, a Josephson-like term, for transfer of pairs
between different condensates in different Fermi surface spots in the special
cases where at least one Fermi surface is near a 2.5 Lifshitz topological
transition. We show that tuning the shape resonances show first, the gap
suppression (like a Fano anti-resonance) driven by configuration interaction
between a BCS condensate and a BEC-like condensate, and second, the gap
amplification (like a Fano resonance) driven by configuration interaction
between BCS condensates in large and small Fermi surfaces. Shape resonances
usually occur in granular nanoscale complex matter (called superstripes)
because of the lattice instability near a 2.5 Lifshitz transition in presence
of interactions. Using a new imaging method, scanning nano-X-ray diffraction,
we have shown the generic formation in high temperature superconductors of a
granular superconducting networks made of striped puddles formed by ordered
oxygen interstitials or ordered local lattice distortions (like static short
range charge density waves). In the superconducting puddles the chemical
potential is tuned to a shape resonance in superconducting gaps and the maximum
Tc occurs where the puddles form scale free superconducting networks.",1212.2733v1
2008-06-03,Quark models of dibaryon resonances in nucleon-nucleon scattering,"We look for $\Delta\Delta$ and $N\Delta$ resonances by calculating $NN$
scattering phase shifts of two interacting baryon clusters of quarks with
explicit coupling to these dibaryon channels. Two phenomenological
nonrelativistic chiral quark models giving similar low-energy $NN$ properties
are found to give significantly different dibaryon resonance structures. In the
chiral quark model (ChQM), the dibaryon system does not resonate in the $NN$
$S$-waves, in agreement with the experimental SP07 $NN$ partial-wave scattering
amplitudes. In the quark delocalization and color screening model (QDCSM), the
$S$-wave NN resonances disappear when the nucleon size $b$ falls below 0.53 fm.
Both quark models give an $IJ^P = 03^+$ $\Delta\Delta$ resonance. At $b=0.52
$fm, the value favored by baryon spectrum, the resonance mass is 2390 (2420)
MeV for the ChQM with quadratic (linear) confinement, and 2360 MeV for the
QDCSM. Accessible from the $^3D_3^{NN}$ channel, this resonance is a promising
candidate for the known isoscalar ABC structure seen more clearly in the
$pn$$\to $$d\pi\pi$ production cross section at 2410 MeV in the recent
preliminary data reported by the CELSIUS-WASA Collaboration. In the isovector
dibaryon sector, our quark models give a bound or almost bound
$^5S_2^{\Delta\Delta}$ state that can give rise to a $^1D_2^{NN}$ resonance.
None of the quark models used has bound $N\Delta$ $P$-states that might
generate odd-parity resonances.",0806.0458v2
2019-04-24,A mathematical theory for Fano resonance in a periodic array of narrow slits,"This work concerns resonant scattering by a perfectly conducting slab with
periodically arranged subwavelength slits, with two slits per period. There are
two classes of resonances, corresponding to poles of a scattering problem. A
sequence of resonances has an imaginary part that is nonzero and on the order
of the width $\varepsilon$ of the slits; these are associated with Fabry-Perot
resonance, with field enhancement of order $1/\varepsilon$ in the slits. The
focus of this study is another class of resonances which become real valued at
normal incidence, when the Bloch wavenumber $\kappa$ is zero. These are
embedded eigenvalues of the scattering operator restricted to a period cell,
and the associated eigenfunctions extend to surface waves of the slab that lie
within the radiation continuum. When $0<|\kappa|\ll 1$, the real embedded
eigenvalues will be perturbed as complex-valued resonances, which induce the
Fano resonance phenomenon. We derive the asymptotic expansions of embedded
eigenvalues and their perturbations as resonances when the Bloch wavenumber
becomes nonzero. Based on the quantitative analysis of the diffracted field, we
prove that the Fano-type anomalies occurs for the transmission of energy
through the slab, and show that the field enhancement is of order
$1/(\kappa\varepsilon)$, which is stronger than Fabry-Perot resonance.",1904.11019v3
2022-07-26,Resonant tides in binary neutron star mergers: analytical-numerical relativity study,"Resonant excitations of $f$-modes in binary neutron star coalescences
influence the gravitational waves (GWs) emission in both quasicircular and
highly eccentric mergers and can deliver information on the star interior. Most
models of resonant tides are built using approximate, perturbative approaches
and thus require to be carefully validated against numerical relativity (NR)
simulations in the high-frequency regime. We perform detailed comparisons
between a set of high-resolution NR simulations and the state of the art
effective one body (EOB) model ${\tt TEOBResumS}$ with various tidal potentials
and including a model for resonant tides. For circular mergers, we find that
$f$-mode resonances can improve the agreement between EOB and NR, but there is
no clear evidence that the tidal enhancement after contact is due to a resonant
mechanism. Tidal models with $f$-mode resonances do not consistently reproduce,
at the same time, the NR waveforms and the energetics within the errors, and
their performances is comparable to resummed tidal models without resonances.
For highly eccentric mergers, we show for the first time that our EOB model
reproduces the bursty NR waveform to a high degree of accuracy. However, the
considered resonant model does not capture the $f$-mode oscillations excited
during the encounters and present in the NR waveform. Finally, we analyze
GW170817 with both adiabatic and dynamical tides models and find that the data
shows no evidence in favor of models including dynamical tides. This is in
agreement with the fact that resonant tides are measured at very high
frequencies, which are not available for GW170817 but might be tested with next
generation detectors.",2207.13106v1
2022-09-02,Modeling frequency shifts of collective bubble resonances with the boundary element method,"Increasing the number of closely-packed air bubbles immersed in water changes
the frequency of the Minnaert resonance. The collective interactions between
bubbles in a small ensemble are primarily in the same phase, causing them to
radiate a spherically-symmetric field that peaks at a frequency lower than the
Minnaert resonance for a single bubble. In contrast, large periodic arrays
include bubbles that are further apart than half the wavelength, so that
collective resonances have bubbles oscillating in opposite phases, ultimately
creating a fundamental resonance at a frequency higher than the single-bubble
Minnaert resonance. This work investigates the transition in resonance behavior
using a modal analysis of a mass-spring system and a boundary element method.
We significantly reduce the computational complexity of the full-wave solver to
a linear dependence on the number of bubbles in a rectangular array. The
simulated acoustic fields confirm the initial downshift in resonance frequency
and the strong influence of collective resonances when the array has hundreds
of bubbles covering more than half the wavelength. These results are essential
in understanding the low-frequency resonance characteristics of bubble
ensembles, which have important applications in diverse fields such as
underwater acoustics, quantum physics, and metamaterial design.",2209.01245v2
2005-02-18,Resonances in Ferromagnetic Gratings Detected by Microwave Photoconductivity,"We investigate the impact of microwave excited spin excitations on the DC
charge transport in a ferromagnetic (FM) grating. We observe both resonant and
nonresonant microwave photoresistance. Resonant features are identified as the
ferromagnetic resonance (FMR) and ferromagnetic antiresonance (FMAR). A
macroscopic model based on Maxwell and Landau-Lifschitz equations reveals the
macroscopic nature of the FMAR. The experimental approach and results provide
new insight in the interplay between photonic, spintronic, and charge effects
in FM microstructures.",0502442v1
2006-03-24,Magnetic resonance in a pyrochlore antiferromagnet Gd2Ti2O7,"Electron spin resonance study of frustrated pyrochlore Gd2Ti2O7 is performed
in a wide frequency band for a temperature range 0.4-30 K, which covers
paramagnetic and magnetically ordered phases. The paramagnetic resonance
reveals the spectroscopic g-factor about 2.0 and a temperature dependent
linewidth. In ordered phases magnetic resonance spectra are distinctive for a
nonplanar cubic (or tetrahedral) antiferromagnet with an isotropic
susceptibility. In the high-field saturated phase, weakly-dispersive soft modes
are observed and their field evolution is traced.",0603653v1
2005-04-28,Resonance radiative decays as a tool for its parity determination,"Radiative decays of the spin 1/2 baryonic resonances R with the decay mode R
-> KN in case of small energy release are considered. Pentaquark is an example
of such resonance. It is shown that in case of positive resonance parity
corrections to the soft photon radiation formula are large even at low photon
energies > 20 MeV and structure terms contributions may be essential, if R size
> 1 fm. This effect is absent in case of negative parity. Particularly,
measurements of the gamma spectrum in pentaquark radiative decays may allow us
to determine its parity.",0504268v1
1997-08-14,"S-matrix studies of resonances in A=3,4,5,6, and 12 nucleon systems","Resonances of certain light nuclei are explored by studying the complex pole
structures of the scattering matrices. Among other results we predict the
existence of three-neutron and three-proton resonances, a small spin-orbit
splitting in the low-lying He-5 and Li-5 states and the nonexistence of the
soft dipole resonance in He-6.",9708024v1
1997-12-11,Nucleon resonances in the constituent quark model with chiral symmetry,"The mass spectra of nucleon resonances with spin 1/2, 3/2, and 5/2 are
systematically studied in the constituent quark model with meson-quark
coupling, which is inspired by the spontaneous breaking of chiral symmetry of
QCD.
  The meson-quark coupling gives rise not only to the one-meson-exchange
potential between quarks but also to the self-energy of baryon resonances due
to the existence of meson-baryon decay channels.
  The two contributions are consistently taken into account in the calculation.
  The gross properties of the nucleon resonance spectra are reproduced fairly
well although the predicted mass of N(1440) is too high.",9712042v1
1998-07-03,Scaling Properties of the Giant Dipole Resonance Width in Hot Rotating nuclei,"We study the systematics of the giant dipole resonance width $\Gamma$ in hot
rotating nuclei as a function of temperature $T$, spin $J$ and mass $A$. We
compare available experimental results with theoretical calculations that
include thermal shape fluctuations in nuclei ranging from A=45 to A=208. Using
the appropriate scaled variables, we find a simple phenomenological function
$\Gamma(A,T,J)$ which approximates the global behavior of the giant dipole
resonance width in the liquid drop model. We reanalyze recent experimental and
theoretical results for the resonance width in Sn isotopes and $^{208}$Pb.",9807012v1
2002-02-08,Electromagnetic transitions between giant resonances within a continuum-RPA approach,"A general continuum-RPA approach is developed to describe electromagnetic
transitions between giant resonances. Using a diagrammatic representation for
the three-point Green's function, an expression for the transition amplitude is
derived which allows one to incorporate effects of mixing of single and double
giant resonances as well as to take the entire basis of particle-hole states
into consideration. The radiative widths for E1 transition between the
charge-exchange spin-dipole giant resonance and Gamow-Teller states are
calculated for ^{90}Nb and ^{208}Bi nuclei. The importance of the mixing is
stressed.",0202029v2
2007-08-06,Microstrip resonator for microwaves with controllable polarization,"In this work the authors implemented a resonator based upon microstrip
cavities that permits the generation of microwaves with arbitrary polarization.
Design, simulation, and implementation of the resonators were performed using
standard printed circuit boards. The electric field distribution was mapped
using a scanning probe cavity perturbation technique. Electron spin resonance
using a standard marker was carried out in order to verify the polarization
control from linear to circular.",0708.0777v2
2009-05-04,Berry Phase Coupling and the Cuprate Neutron Scattering Resonance,"We examine the influence of coupling between particle-hole and
particle-particle spin fluctuations on the inelastic neutron scattering
resonance (INSR) in cuprate superconductors in both weak and strong interaction
limits. For weak-interactions in the particle-hole channel, we find that the
interchannel coupling can eliminate the resonance. For strong interactions
which drive the system close to a $\bm{Q}=(\pi,\pi)$ magnetic instablity, the
resonance frequency always approaches zero but its value is influenced by the
interchannel coupling. We comment on constraints imposed on cuprate physics by
the INSR phenomenology, and a comparison between the cuprates and the
newly-discovered iron pnictide superconductors is discussed.",0905.0464v1
2009-09-07,Anomalous magnetotransport and cyclotron resonance of high mobility magnetic 2DHGs in the quantum Hall regime,"Low temperature magnetotransport measurements and far infrared transmission
spectroscopy are reported in molecular beam epitaxial grown two-dimensional
hole systems confined in strained InAs quantum wells with magnetic impurities
in the channel. The interactions of the free holes spin with the magnetic
moment of 5/2 provided by manganese features intriguing localization phenomena
and anomalies in the Hall and the quantum Hall resistance. In magnetic field
dependent far infrared spectroscopy measurements well pronounced cyclotron
resonance and an additional resonance are found that indicates an anticrossing
with the cyclotron resonance.",0909.1124v1
2009-12-23,"$πΞ$ Correlations: an Interweaving of Resonance Interaction, Channel Coupling and Coulomb Effects","A method is presented for analysis of correlation function of two
non-identical particles with strong and Coulomb interactions, resonance
formation, channel coupling and spin structure. For resonance reactions we
derive a formula giving the small distance contribution to the correlation
function. The formalism is used to analyze the preliminary RHIC data on
$\pi^{\pm} \Xi^{\mp}$ correlation measurements. The $\Xi^{*}(1530)$ resonance
is successfully described. The $\pi \Xi$ source size is obtained.",0912.4693v2
2010-09-16,Engineering two-mode squeezed states of cold atomic clouds with a superconducting stripline resonator,"A scheme is proposed for engineering two-mode squeezed states of two
separated cold atomic clouds positioned near the surface of a superconducting
stripline resonator. Based on the coherent magnetic coupling between the atomic
spins and a stripline resonator mode, the desired two-mode squeezed state can
be produced via precisely control on the dynamics of the system. This scheme
may be used to realize scalable on-chip quantum networks with cold atoms
coupling to stripline resonators.",1009.3140v1
2011-11-05,Top quark as a resonance,"We suggest the description of the dressed fermion propagator with parity
non-conservation in the form with separated positive and negative energy poles.
We found general form of the $\gamma$-matrix off-shell projectors and
corresponding resonance factors. The parity violation leads to deviation of
resonance factors from the naive Breit--Wigner form and to appearance of
non-trivial spin corrections. However, for top quark with SM vertex the
resonance factor returns to the standard one due to $\Gamma/m\ll1$.",1111.1284v3
2014-05-13,Influence of the ESR saturation on the power sensitivity of cryogenic sapphire resonators,"Here, we study the paramagnetic ions behavior in presence of a strong
microwave electromagnetic field sustained inside a cryogenic sapphire
whispering gallery mode resonator. The high frequency measurement resolution
that can be now achieved by comparing two CSOs permit for the first time to
observe clearly the non-linearity of the resonator power sensitivity. These
observations that in turn allow us to optimize the CSO operation, are well
explained by the Electron Spin Resonance (ESR) saturation of the paramagnetic
impurities contained in the sapphire crystal.",1405.3081v1
2018-07-29,Logical Fallacy of using the Electric Field in Non-resonant Near-field Optics,"We find that the electric field is not a suitable physical quantity to
describe the response of a non-metallic material in the study of non-resonant
near-field optics. In practice, we show the spin-less one-electron two-level
system responds differently to longitudinal and transverse electric fields
under the non-resonant condition. This difference originates from the
non-relativistic nature of the system, and should exist in actual many-electron
systems. For this type of system, it is a logical fallacy to use the
constitutive equation in terms of the total electric field and the associated
permittivity. Recognizing this fallacy, both experimental and theoretical
progress is needed in the field of non-resonant near-field optics of
non-metallic materials.",1807.10991v1
2020-05-30,Configurational entropy and spectroscopy of pomeron resonances in dynamical AdS/QCD,"Pomeron resonances in AdS/QCD are here studied using the configurational
entropy (CE). The concept of CE Regge trajectories, associating the CE of the
pomeron resonances with both their spin $J^{PC}$ and to their mass spectra, is
used to derive the mass spectra of higher $J^{PC}$ pomeron resonances. For it,
the linear, the exponential modified and the anomalous quadratic dilatonic
models, each one with linear and logarithmic anomalous corrections, are
employed. Several methods are implemented, hybridizing AdS/QCD and established
data of lattice QCD.",2006.00332v2
2022-09-12,Ultra-High Q Nanomechanical Resonators for Force Sensing,"Nanomechanical resonators with ultra-high quality factors have become a
central element in fundamental research, enabling measurements below the
standard quantum limit and the preparation of long-lived quantum states. Here,
I propose that such resonators will allow the detection of electron and nuclear
spins with high spatial resolution, paving the way to future nanoscale magnetic
resonance imaging instruments. The article lists the challenges that must be
overcome before this vision can become reality, and indicates potential
solutions.",2209.05183v1
2024-01-11,Impact of the molecular resonances on the 12C+12C fusion reaction rate,"The properties of the low-energy 12C+12C molecular resonances, which
potentially enhance the fusion reaction rate at low temperatures, have been
investigated by a full-microscopic nuclear model employing various nuclear
energy density functionals. We show that some density functionals plausibly
describe the observed high-spin 12C+12C molecular resonances and predict many
0+ and 2+ resonances at low energies, which enhance the reaction rate. We also
discuss how the uncertainty in the nuclear energy density functionals
propagates to that of the reaction rate.",2401.05803v1
2003-01-28,Stopping inward planetary migration by a toroidal magnetic field,"We calculate the linear torque exerted by a planet on a circular orbit on a
disc containing a toroidal magnetic field. All fluid perturbations are singular
at the so--called magnetic resonances, where the Doppler shifted frequency of
the perturbation matches that of a slow MHD wave propagating along the field
line. These lie on both sides of the corotation radius. Waves propagate outside
the Lindblad resonances, and also in a restricted region around the magnetic
resonances. The magnetic resonances contribute to a significant global torque
which, like the Lindblad torque, is negative (positive) inside (outside) the
planet's orbit. Since these resonances are closer to the planet than the
Lindblad resonances, the torque they contribute dominates over the Lindblad
torque if the magnetic field is large enough. In addition, if beta=c^2/v_A^2
increases fast enough with radius, the outer magnetic resonance becomes less
important and the total torque is then negative, dominated by the inner
magnetic resonance. This leads to outward migration of the planet. Even for
beta=100 at corotation, a negative torque may be obtained. A planet migrating
inward through a nonmagnetized region of a disc would then stall when reaching
a magnetized region. It would then be able to grow to become a terrestrial
planet or the core of a giant planet. In a turbulent magnetized disc in which
the large scale field structure changes sufficiently slowly, a planet may
alternate between inward and outward migration, depending on the gradients of
the field encountered. Its migration could then become diffusive, or be limited
only to small scales.",0301556v1
2015-04-20,Lindblad Zones: resonant eccentric orbits to aid bar and spiral formation in galaxy discs,"The apsidal precession frequency in a fixed gravitational potential increases
with the radial range of the orbit (eccentricity). Although the frequency
increase is modest it can have important implications for wave dynamics in
galaxy discs, which have not been previously explored in detail. One of the
most interesting consequences is that for a given pattern frequency, each
Lindblad resonance does not exist in isolation, but rather is the parent of a
continuous sequence of resonant radii, a Lindblad Zone, with each radius in
this zone characterized by a specific eccentricity. In the epicyclic
approximation the precession or epicyclic frequency does not depend on epicycle
size, and this phenomenon is not captured. A better approximation for eccentric
orbits is provided by p-ellipse curves (Struck 2006), which do exhibit this
effect. Here the p-ellipse approximation and precession-eccentricity relation
are used as tools for finding the resonant radii generated from various
Lindblad parent resonances. Simple, idealized examples, in flat rotation curve
and near solid-body discs, are used to show that ensembles of eccentric
resonant orbits excited in Lindblad Zones can provide a backbone for generating
a variety of (kinematic) bars and spiral waves. In cases balancing
radius-dependent circular frequencies and eccentricity-dependent precession, a
range of resonant orbits can maintain their form in the pattern frame, and do
not wind up. Eccentric resonance orbits require a strong perturbation to excite
them, and may be produced mostly in galaxy interactions or by strong internal
disturbances.",1504.05161v1
2016-06-16,Calculating rotating hydrodynamic and magneto-hydrodynamic waves to understand magnetic effects on dynamical tides,"For understanding magnetic effects on dynamical tides, we study the rotating
magneto-hydrodynamic (MHD) flow driven by harmonic forcing. The linear
responses are analytically derived in a periodic box under the local WKB
approximation. Both the kinetic and Ohmic dissipations at the resonant
frequencies are calculated and the various parameters are investigated.
Although magnetic pressure may be negligible compared to thermal pressure,
magnetic field can be important for the first-order perturbation, e.g.
dynamical tides. It is found that magnetic field splits the resonant frequency,
namely the rotating hydrodynamic flow has only one resonant frequency but the
rotating MHD flow has two, one positive and the other negative. In the weak
field regime the dissipations are asymmetric around the two resonant
frequencies and this asymmetry is more striking with a weaker magnetic field.
It is also found that both the kinetic and Ohmic dissipations at the resonant
frequencies are inversely proportional to the Ekman number and the square of
wavenumber. The dissipation at the resonant frequency on small scales is almost
equal to the dissipation at the non-resonant frequencies, namely the resonance
takes its effect on the dissipation at intermediate length scales. Moreover,
the waves with phase propagation perpendicular to magnetic field are much more
damped. It is also interesting to find that the frequency-averaged dissipation
is constant. This result suggests that in compact objects magnetic effects on
tidal dissipation should be considered.",1606.06232v1
2018-07-10,Nonreciprocal control and cooling of phonon modes in an optomechanical system,"Phononic resonators play important roles in settings that range from
gravitational wave detectors to cellular telephones. They serve as
high-performance transducers, sensors, and filters by offering low dissipation,
tunable coupling to diverse physical systems, and compatibility with a wide
range of frequencies, materials, and fabrication processes. Systems of phononic
resonators typically obey reciprocity, which ensures that the phonon
transmission coefficient between any two resonators is independent of the
direction of transmission. Reciprocity must be broken to realize devices (such
as isolators and circulators) that provide one-way propagation of acoustic
energy between resonators. Such devices are crucial for protecting active
elements, mitigating noise, and operating full-duplex transceivers. To date,
nonreciprocal phononic devices have not combined the features necessary for
robust operation: strong nonreciprocity, in situ tunability, compact
integration, and continuous operation. Furthermore, they have been applied only
to coherent signals (rather than fluctuations or noise), and have been realized
exclusively in travelling-wave systems (rather than resonators). Here we
describe a cavity optomechanical scheme that produces robust nonreciprocal
coupling between phononic resonators. This scheme provides ~ 30 dB of isolation
and can be tuned in situ simply via the phases of the drive tones applied to
the cavity. In addition, by directly monitoring the resonators' dynamics we
show that this nonreciprocity can be used to control thermal fluctuations, and
that this control represents a new resource for cooling phononic resonators.",1807.03484v1
2022-01-14,Topological Supercavity Resonances In the Finite System,"Acoustic resonant cavities play a vital role in modern acoustical systems.
They have led to many essential applications for noise control, biomedical
ultrasonics, and underwater communications. The ultrahigh quality-factor
resonances are highly desired for some applications like high-resolution
acoustic sensors and acoustic lasers. Here, we theoretically propose and
experimentally demonstrate a new class of supercavity resonances in a coupled
acoustic resonators system, arising from the merged bound states in the
continuum (BICs) in geometry space. We demonstrate their topological origin by
explicitly calculating their topological charges before and after BIC merging,
accompanied by charges annihilation. Comparing with other types of BICs, they
are robust to the perturbation brought by fabrication imperfection. Moreover,
we found that such supercavity modes can be linked with the Friedrich-Wintgen
BICs supported by an entire rectangular (cuboid) resonator sandwiched between
two rectangular (or circular) waveguides, and thus more supercavity modes are
constructed. Then, we fabricate these coupled resonators and experimentally
confirm such a unique phenomenon: moving, merging, and vanishing of BICs by
measuring their reflection spectra, which show good agreement with the
numerical simulation and theoretical prediction of mode evolution. Finally,
given the similar wave nature of acoustic and electromagnetic waves, such
merged BICs also can be constructed in a coupled photonic resonator system. Our
results may find exciting applications in acoustic and photonics, such as
enhanced acoustic emission, filtering, and sensing.",2201.05324v1
2022-02-23,Quarter-wave Resonator Based Tunable Coupler for Xmon Qubits,"We propose a scheme of tunable coupler based on quarter-wave resonator for
scalable quantum integrated circuits. The open end of the T-type resonator is
capacitively coupled to two Xmon qubits, while another end is an asymmetric
dc-SQUID which dominates the inductive energy of coupler resonator. The
dc-Current applied through the flux bias line could change the magnetic flux
inside the dc-SQUID, so the frequency of coupler resonator can be effectively
tuned and the qubit-qubit coupling can be totally switched off. As the increase
of junction asymmetry for the dc-SQUID, the coupling of SQUID's effective phase
difference and cavity modes become smaller at required working frequency regime
of coupler resonator, and this could reduce the descent of the resonator's
quality factor. The separation between two cross-capacitor can be larger with
help of transverses width of the T-shape resonator, and then the ZZ crosstalk
coupling can be effectively suppressed. The asymmetric dc-SQUID is about 5
millimeters away from the Xmon qubits and only needs a small current on the
flux bias line, which in principle creates less flux noises to superconducting
Xmon qubits.",2202.11594v3
2008-05-28,Plasmons in the presence of Tamm-Shockley states with Rashba splitting at noble metal surfaces,"Au(111) or similar noble metal surfaces feature Tamm-Shockley surface states
that are known to possess considerable spin-orbit splitting of the Rashba type
of order $\Delta=0.1$ eV. When interacting with an electromagnetic field such
states are expected to have resonances when the frequency of the field is near
the energy of the spin-orbit splitting $\Delta$. These resonances originate in
the intersubband transitions between spin-split subbands. Such resonances can
be observed in the frequency dependence of the surface impedance. Plasmons in
thin metal films are gapless and can be strongly affected by these spin
resonances, acquiring significant modification of the spectrum when it
intersects the $\omega=\Delta$ line. Finally, an interesting demonstration of
the intersubband resonances can be obtained when metal films are coated with
ionic dielectrics that have a frequency of longitudinal/transverse optical
phonons above/below $\Delta$. The dielectric function between the two optical
phonon frequencies is negative which forbids propagation of conventional
plasmon-polaritons. However, the presence of spin-orbit-split surface states
allows plasmon-polaritons to exist in this otherwise forbidden range of
frequencies.",0805.4255v2
2010-11-23,Resonant recoil in extreme mass ratio binary black hole mergers,"The inspiral and merger of a binary black hole system generally leads to an
asymmetric distribution of emitted radiation, and hence a recoil of the remnant
black hole directed opposite to the net linear momentum radiated. The recoil
velocity is generally largest for comparable mass black holes and particular
spin configurations, and approaches zero in the extreme mass ratio limit. It is
generally believed that for extreme mass ratios eta<<1, the scaling of the
recoil velocity is V {\propto} eta^2, where the proportionality coefficient
depends on the spin of the larger hole and the geometry of the system (e.g.
orbital inclination). Here we show that for low but nonzero inclination
prograde orbits and very rapidly spinning large holes (spin parameter
a*>0.9678) the inspiralling binary can pass through resonances where the
orbit-averaged radiation-reaction force is nonzero. These resonance crossings
lead to a new contribution to the kick, V {\propto} eta^{3/2}. For these
configurations and sufficiently extreme mass ratios, this resonant recoil is
dominant. While it seems doubtful that the resonant recoil will be
astrophysically significant, its existence suggests caution when extrapolating
the results of numerical kick results to extreme mass ratios and near-maximal
spins.",1011.4987v3
2012-08-20,On the spin and parity of a single-produced resonance at the LHC,"The experimental determination of the properties of the newly discovered
boson at the Large Hadron Collider is currently the most crucial task in high
energy physics. We show how information about the spin, parity, and, more
generally, the tensor structure of the boson couplings can be obtained by
studying angular and mass distributions of events in which the resonance decays
to pairs of gauge bosons, $ZZ, WW$, and $\gamma \gamma$. A complete Monte Carlo
simulation of the process $pp \to X \to VV \to 4f$ is performed and verified by
comparing it to an analytic calculation of the decay amplitudes $X \to VV \to
4f$. Our studies account for all spin correlations and include general
couplings of a spin $J=0,1,2$ resonance to Standard Model particles. We also
discuss how to use angular and mass distributions of the resonance decay
products for optimal background rejection. It is shown that by the end of the 8
TeV run of the LHC, it might be possible to separate extreme hypotheses of the
spin and parity of the new boson with a confidence level of 99% or better for a
wide range of models. We briefly discuss the feasibility of testing scenarios
where the resonances is not a parity eigenstate.",1208.4018v3
2012-12-03,New Skyrme energy density functional for a better description of the Gamow-Teller Resonance,"We present a new Skyrme energy density functional (EDF) named SAMi [Phys.
Rev. C 86 031306(R)]. This interaction has been accurately calibrated to
reproduce properties of doubly-magic nuclei and infinite nuclear matter. The
novelties introduced in the model and fitting protocol of SAMi are crucial for
a better description of the Gamow-Teller Resonance (GTR). Those are, on one
side, the two-component spin-orbit potential needed for describing different
proton high-angular momentum spin-orbit splitings and, on the other side, the
careful description of the empirical hierarchy and positive values found in
previous analysis of the spin (G_0) and spin-isospin (G_0^') Landau-Migdal
parameters: 0 < G_0 < G_0^', a feature that many of available Skyrme forces
fail to reproduce. When employed within the self-consistent Hartree-Fock plus
Random Phase Approximation, SAMi produces results on ground and excited state
nuclear properties that are in good agreement with experimental findings. This
is true not only for the GTR, but also for the Spin Dipole Resonance (SDR) and
the Isobaric Analog Resonance (IAR) as well as for the non charge-exchange
Isoscalar Giant Monopole (ISGMR) and Isovector Giant Dipole (IVGDR) and
Quadrupole Resonances (IVGQR).",1212.0384v1
2012-09-07,Spin-orbit coupling for tidally evolving super-Earths,"We investigate the spin behavior of close-in rocky planets and the
implications for their orbital evolution. Considering that the planet rotation
evolves under simultaneous actions of the torque due to the equatorial
deformation and the tidal torque, both raised by the central star, we analyze
the possibility of temporary captures in spin-orbit resonances. The results of
the numerical simulations of the exact equations of motions indicate that,
whenever the planet rotation is trapped in a resonant motion, the orbital decay
and the eccentricity damping are faster than the ones in which the rotation
follows the so-called pseudo-synchronization. Analytical results obtained
through the averaged equations of the spin-orbit problem show a good agreement
with the numerical simulations. We apply the analysis to the cases of the
recently discovered hot super-Earths Kepler-10 b, GJ 3634 b and 55 Cnc e. The
simulated dynamical history of these systems indicates the possibility of
capture in several spin-orbit resonances; particularly, GJ 3634 b and 55 Cnc e
can currently evolve under a non-synchronous resonant motion for suitable
values of the parameters. Moreover, 55 Cnc e may avoid a chaotic rotation
behavior by evolving towards synchronization through successive temporary
resonant trappings.",1209.1580v1
2018-02-06,Odd and even modes of neutron spin resonance in the bilayer iron-based superconductor CaKFe$_4$As$_4$,"We report an inelastic neutron scattering study on the spin resonance in the
bilayer iron-based superconductor CaKFe$_4$As$_4$. In contrast to its
quasi-two-dimensional electron structure, three strongly $L$-dependent modes of
spin resonance are found below $T_c=35$ K. The mode energies are below and
linearly scale with the total superconducting gaps summed on the nesting hole
and electron pockets, essentially in agreement with the results in cuprate and
heavy fermion superconductors. This observation supports the sign-reversed
Cooper pairing mechanism under multiple pairing channels and resolves the
long-standing puzzles concerning the broadening and dispersive spin resonance
peak in iron pnictides. More importantly, the triple resonant modes can be
classified into odd and even symmetries with respect to the distance of Fe-Fe
planes within the Fe-As bilayer unit. Thus, our results closely resemble those
in the bilayer cuprates with nondegenerate spin excitations, suggesting that
these two high-$T_c$ superconducting families share a common nature.",1802.01901v2
1998-06-30,Structure and Spin Dynamics of La$_{0.85}$Sr$_{0.15}$MnO$_3$,"Neutron scattering has been used to study the structure and spin dynamics of
La$_{0.85}$Sr$_{0.15}$MnO$_3$. The magnetic structure of this system is
ferromagnetic below T_C = 235 K. We see anomalies in the Bragg peak intensities
and new superlattice peaks consistent with the onset of a spin-canted phase
below T_{CA} = 205 K, which appears to be associated with a gap at q = (0, 0,
0.5) in the spin-wave spectrum. Anomalies in the lattice parameters indicate a
concomitant lattice distortion. The long-wavelength magnetic excitations are
found to be conventional spin waves, with a gapless (< 0.02 meV) isotropic
dispersion relation $E = Dq^2$. The spin stiffness constant D has a $T^{5/2}$
dependence at low T, and the damping at small q follows $q^4T^{2}$. An
anomalously strong quasielastic component, however, develops at small wave
vector above 200 K and dominates the fluctuation spectrum as T -> T_C. At
larger q, on the other hand, the magnetic excitations become heavily damped at
low temperatures, indicating that spin waves in this regime are not eigenstates
of the system, while raising the temperature dramatically increases the
damping. The strength of the spin-wave damping also depends strongly on the
symmetry direction in the crystal. These anomalous damping effects are likely
due to the itinerant character of the $e_g$ electrons.",9806381v1
2000-09-27,Microscopic theory of the two-dimensional quantum antiferromagnet in a paramagnetic phase,"We have developed a consistent theory of the Heisenberg quantum
antiferromagnet in the disordered phase with a short range antiferromagnetic
order on the basis of the path integral for spin coherent states. We have
presented the Lagrangian of the theory in a form which is explicitly invariant
under rotations and found natural variables in terms of which one can construct
a natural perturbation theory. The short wave spin fluctuations are similar to
those in the spin wave theory and they are of the order of the parameter $1/2s$
where $s$ is the spin magnitude. The long wave spin fluctuations are governed
by the nonlinear sigma model and are of the order of the the parameter 1/N,
where $N$ is the number of field components. We also have shown that the short
wave spin fluctuations must be evaluated accurately and the continuum limit in
time of the path integral must be performed after all summation over the
frequencies $\omega$. In the framework of our approach we have obtained the
response function for the spin fluctuations for all region of the frequency
$\omega$ and the wave vector ${\bf k}$ and have calculated the free energy of
the system. We have also reproduced the known results for the spin correlation
length in the lowest order in 1/N.",0009427v2
2007-04-12,Temperature-driven transition from the Wigner Crystal to the Bond-Charge-Density Wave in the Quasi-One-Dimensional Quarter-Filled band,"It is known that within the interacting electron model Hamiltonian for the
one-dimensional 1/4-filled band, the singlet ground state is a Wigner crystal
only if the nearest neighbor electron-electron repulsion is larger than a
critical value. We show that this critical nearest neighbor Coulomb interaction
is different for each spin subspace, with the critical value decreasing with
increasing spin. As a consequence, with the lowering of temperature, there can
occur a transition from a Wigner crystal charge-ordered state to a spin-Peierls
state that is a Bond-Charge-Density Wave with charge occupancies different from
the Wigner crystal. This transition is possible because spin excitations from
the spin-Peierls state in the 1/4-filled band are necessarily accompanied by
changes in site charge densities. We apply our theory to the 1/4-filled band
quasi-one-dimensional organic charge-transfer solids in general and to 2:1
tetramethyltetrathiafulvalene (TMTTF) and tetramethyltetraselenafulvalene
(TMTSF) cationic salts in particular. We believe that many recent experiments
strongly indicate the Wigner crystal to Bond-Charge-Density Wave transition in
several members of the TMTTF family. We explain the occurrence of two different
antiferromagnetic phases but a single spin-Peierls state in the generic phase
diagram for the 2:1 cationic solids. The antiferromagnetic phases can have
either the Wigner crystal or the Bond-Charge-Spin-Density Wave charge
occupancies. The spin-Peierls state is always a Bond-Charge-Density Wave.",0704.1656v2
2011-02-18,{\it Ab initio} studies of spin-spiral waves and exchange interactions in 3{\it d} transition metal atomic chains,"The total energy of the transverse spin-spiral wave as a function of the wave
vector for all 3$d$ transition metal atomic chains has been calculated within
{\it ab initio} density functional theory with generalized gradient
approximation. It is predicted that at the equilibrium bond length, the V, Mn,
and Fe chains have a stable spin spiral structure, whilst the magnetic ground
state of the Cr, Co and Ni chains remains to be collinear. Furthermore, all the
exchange interaction parameters of the 3$d$ transition metal chains are
evaluated by using the calculated energy dispersion relations of the
spin-spiral waves. Interestingly, it is found that the magnetic couplings in
the V, Mn and Cr chains are frustrated (i.e., the second near neighbor exchange
interaction is antiferromagnetic), and this leads to the formation of the
stable spin-spiral structure in these chains. The spin-wave stiffness constant
of these 3$d$ metal chains is also evaluated and is found to be smaller than
its counterpart in bulk and monolayer systems. The upper limit (in the order of
100 Kelvins) of the possible magnetic phase transition temperature in these
atomic chains is also estimated within the mean field approximation. The
electronic band structure of the spin-spiral structures have also been
calculated. It is hoped that the interesting findings here of the stable
spin-spiral structure and frustrated magnetic interaction in the 3$d$
transition metal chains would stimulate further theoretical and experimental
research in this field.",1102.3737v1
2015-05-14,"First-principles calculations of exchange interactions, spin waves, and temperature dependence of magnetization in inverse-Heusler-based spin gapless semiconductors","Employing first principles electronic structure calculations in conjunction
with the frozen-magnon method we calculate exchange interactions, spin-wave
dispersion, and spin-wave stiffness constants in inverse-Heusler-based spin
gapless semiconductor (SGS) compounds Mn$_2$CoAl, Ti$_2$MnAl, Cr$_2$ZnSi,
Ti$_2$CoSi and Ti$_2$VAs. We find that their magnetic behavior is similar to
the half-metallic ferromagnetic full-Heusler alloys, i.e., the intersublattice
exchange interactions play an essential role in the formation of the magnetic
ground state and in determining the Curie temperature, $T_\mathrm{c}$. All
compounds, except Ti$_2$CoSi possess a ferrimagnetic ground state. Due to the
finite energy gap in one spin channel, the exchange interactions decay sharply
with the distance, and hence magnetism of these SGSs can be described
considering only nearest and next-nearest neighbor exchange interactions. The
calculated spin-wave dispersion curves are typical for ferrimagnets and
ferromagnets. The spin-wave stiffness constants turn out to be larger than
those of the elementary 3$d$-ferromagnets. Calculated exchange parameters are
used as input to determine the temperature dependence of the magnetization and
$T_\mathrm{c}$ of the SGSs. We find that the $T_\mathrm{c}$ of all compounds is
much above the room temperature. The calculated magnetization curve for
Mn$_2$CoAl as well as the Curie temperature are in very good agreement with
available experimental data. The present study is expected to pave the way for
a deeper understanding of the magnetic properties of the inverse-Heusler-based
SGSs and enhance the interest in these materials for application in spintronic
and magnetoelectronic devices.",1505.03632v1
2019-11-04,Spin-helix driven insulating phase in two dimensional lattice,"Motivated by emergent $SU(2)$ symmetry in the spin orbit coupled system, we
study the spin helix driven insulating phase in two dimensional lattice. When
both Rashba and Dresselhaus spin orbit couplings are present, the perfect Fermi
surface nesting occurs at a special condition depending on the lattice
geometry. In this case, the energies of spin up at any wave vector $\vec{k}$
are equivalent to the ones of spin down at $\vec{k}\!+\!\vec{Q}$ with so-called
the \textit{shifting wave vector} $\vec{Q}$. Thus, the system stabilizes
magnetic insulator with spiral like magnetic ordering even in the presence of
tiny electron-electron interaction where the magnetic ordering wave vector is
proportional to $\vec{Q}$. We first show the condition for existence of the
\textit{shifting wave vector} in general lattice model and emergent $SU(2)$
symmetry in the spin orbit coupled system. Then, we exemplify this in square
lattice at half filling and discuss the insulating phase with (non-) coplanar
spin density wave and charge order. Our study emphasizes possible new types of
two dimensional magnetic materials and can be applicable to various van-der
Waals materials and their heterostructures with the control of electric field,
strain and pressure.",1911.01440v1
2021-08-01,Directional excitation of a high-density magnon gas using coherently driven spin waves,"Controlling magnon densities in magnetic materials enables driving spin
transport in magnonic devices. We demonstrate the creation of large,
out-of-equilibrium magnon densities in a thin-film magnetic insulator via
microwave excitation of coherent spin waves and subsequent multi-magnon
scattering. We image both the coherent spin waves and the resulting incoherent
magnon gas using scanning-probe magnetometry based on electron spins in
diamond. We find that the gas extends unidirectionally over hundreds of
micrometers from the excitation stripline. Surprisingly, the gas density far
exceeds that expected for a boson system following a Bose-Einstein distribution
with a maximum value of the chemical potential. We characterize the momentum
distribution of the gas by measuring the nanoscale spatial decay of the
magnetic stray fields. Our results show that driving coherent spin waves leads
to a strong out-of-equilibrium occupation of the spin-wave band, opening new
possibilities for controlling spin transport and magnetic dynamics in target
directions.",2108.00467v1
2017-01-09,Spin-Wave versus Joule Heating in Spin-Hall-Effect/Spin-Transfer-Torque Driven Cr/Heusler/Pt Waveguides,"We present a time-resolved study of the DC-current driven magnetization
dynamics in a microstructured Cr/Heusler/Pt waveguide by means of Brillouin
light scattering. A reduction of the effective spin-wave damping via the
spin-transfer-torque effect leads to a strong increase in the magnon density.
This is accompanied by a decrease of the spin-wave frequencies. By evaluating
the time scales of these effects, the origin of this frequency shift can be
identified. However, recently, we found that the experimental setup partially
influences the decay of the spin-wave intensity after the current pulse is
switched off. Thus, further investigations on the presented effect are needed
to allow for a more detailed analysis. For this reason, we need to withdraw the
manuscript at this point and might publish an updated version later.",1701.02094v2
2023-05-07,Effect of random antiferromagnetic exchange on the spin waves in a three-dimensional Heisenberg ferromagnet,"Neutron scattering is used to study spin waves in the three-dimensional
Heisenberg ferromagnet YTiO$_3$, with spin-spin exchange disorder introduced
$via$ La-substitution at the Y site. No significant changes are observed in the
spin-wave dispersion up to a La concentration of 20%. However, a strong
broadening of the spectrum is found, indicative of shortened spin-wave
lifetimes. Density-functional theory calculations predict minimal changes in
exchange constants as a result of average structural changes due to La
substitution, in agreement with the data. The absence of significant changes in
the spin-wave dispersion, the considerable lifetime effect, and the reduced
ordered magnetic moment previously observed in the La-substituted system are
qualitatively captured by an isotropic, nearest-neighbor, three-dimensional
Heisenberg ferromagnet model with random antiferromagnetic exchange. We
therefore establish Y$_{1-x}$La$_x$TiO$_3$ as a model system to study the
effect of antiferromagnetic spin-exchange disorder in a three-dimensional
Heisenberg ferromagnet.",2305.04280v1
2013-03-29,Particle scattering in turbulent plasmas with amplified wave modes,"High-energy particles stream during coronal mass ejections or flares through
the plasma of the solar wind. This causes instabilities, which lead to wave
growth at specific resonant wave numbers, especially within shock regions.
These amplified wave modes influence the turbulent scattering process
significantly. In this paper, results of particle transport and scattering in
turbulent plasmas with excited wave modes are presented. The method used is a
hybrid simulation code, which treats the heliospheric turbulence by an
incompressible magnetohydrodynamic approach separately from a kinetic particle
description. Furthermore, a semi-analytical model using quasilinear theory
(QLT) is compared to the numerical results. This paper aims at a more
fundamental understanding and interpretation of the pitch-angle scattering
coefficients. Our calculations show a good agreement of particle simulations
and the QLT for broad-band turbulent spectra; for higher turbulence levels and
particle beam driven plasmas, the QLT approximation gets worse. Especially the
resonance gap at $\mu=0$ poses a well-known problem for QLT for steep
turbulence spectra, whereas test-particle computations show no problems for the
particles to scatter across this region. The reason is that the sharp resonant
wave--particle interactions in QLT are an oversimplification of the broader
resonances in test-particle calculations, which result from nonlinear effects
not included in the QLT. We emphasise the importance of these results for both
numerical simulations and analytical particle transport approaches, especially
the validity of the QLT.",1303.7463v1
2014-02-07,A route to thermalization in the $α$-Fermi-Pasta-Ulam system,"We study the original $\alpha$-Fermi-Pasta-Ulam (FPU) system with $N=16,32$
and $64$ masses connected by a nonlinear quadratic spring. Our approach is
based on resonant wave-wave interaction theory, i.e. we assume that, in the
weakly nonlinear regime (the one in which Fermi was originally interested), the
large time dynamics is ruled by exact resonances. After a detailed analysis of
the $\alpha$-FPU equation of motion, we find that the first non trivial
resonances correspond to six-wave interactions. Those are precisely the
interactions responsible for the thermalization of the energy in the spectrum.
We predict that for small amplitude random waves the time scale of such
interactions is extremely large and it is of the order of $1/\epsilon^8$, where
$\epsilon$ is the small parameter in the system. The wave-wave interaction
theory is not based on any threshold: equipartition is predicted for arbitrary
small nonlinearity. Our results are supported by extensive numerical
simulations. A key role in our finding is played by the {\it Umklapp} (flip
over) resonant interactions, typical of discrete systems. The thermodynamic
limit is also briefly discussed.",1402.1603v2
2014-08-11,Magneto-optical resonance of electromagnetically induced absorption with high contrast and narrow width in a vapour cell with buffer gas,"The method for observing the high-contrast and narrow-width resonances of
electromagnetically induced absorption (EIA) in the Hanle configuration under
counterpropagating light waves is proposed. We theoretically analyze the
absorption of a probe light wave in presence of counterpropagating one with the
same frequency as the function of a static magnetic field applied along the
vectors of light waves, propagating in a vapour cell. Here, as an example, we
study a ""dark"" type of atomic dipole transition Fg=1-->Fe=1 in D1 line of 87Rb,
where usually the electromagnetically induced transparency (EIT) can be
observed. To obtain the EIA signal one should proper chose the polarizations of
light waves and intensities. In contrast of regular schemes for observing EIA
signals (in a single travelling light wave in the Hanle configuration or in a
bichromatic light field consisted of two travelling waves), the proposed scheme
allows one to use buffer gas to significantly enhance properties of the
resonance. Also the dramatic influence of atomic transition openness on
contrast of the resonance is revealed, that gives great advantage in comparison
with cyclic atomic transitions. The obtained results can be interesting in
high-resolution spectroscopy, nonlinear and magneto-optics.",1408.2338v1
2015-06-22,Visualization of phase-coherent electron interference in a ballistic graphene Josephson junction,"Interference of standing waves in electromagnetic resonators forms the basis
of many technologies, from telecommunications and spectroscopy to detection of
gravitational waves. However, unlike the confinement of light waves in vacuum,
the interference of electronic waves in solids is complicated by boundary
properties of the crystal, notably leading to electron guiding by atomic-scale
potentials at the edges. Understanding the microscopic role of boundaries on
coherent wave interference is an unresolved question due to the challenge of
detecting charge flow with submicron resolution. Here we employ Fraunhofer
interferometry to achieve real-space imaging of cavity modes in a graphene
Fabry-Perot resonator, embedded between two superconductors to form a Josephson
junction. By directly visualizing current flow using Fourier methods, our
measurements reveal surprising redistribution of current on and off resonance.
These findings provide direct evidence of separate interference conditions for
edge and bulk currents and reveal the ballistic nature of guided edge states.
Beyond equilibrium, our measurements show strong modulation of the multiple
Andreev reflection amplitude on an off resonance, a direct measure of the
gate-tunable change of cavity transparency. These results demonstrate that,
contrary to the common belief, electron interactions with realistic disordered
edges facilitate electron wave interference and ballistic transport.",1506.06734v1
2019-04-14,An asymptotic hyperbolic-elliptic model for flexural-seismic metasurfaces,"We consider a periodic array of resonators, formed from Euler-Bernoulli
beams, attached to the surface of an elastic half-space. Earlier studies of
such systems have concentrated on compressional resonators. In this paper we
consider the effect of the flexural motion of the resonators, adapting a
recently established asymptotic methodology that leads to an explicit scalar
hyperbolic equation governing the propagation of Rayleigh-like waves. Compared
with classical approaches, the asymptotic model yields a significantly simpler
dispersion relation, with closed form solutions, shown to be accurate for
surface wave-speeds close to that of the Rayleigh wave. Special attention is
devoted to the effect of various junction conditions joining the beams to the
elastic half-space which arise from considering flexural motion and are not
present for the case of purely compressional resonators. Such effects are shown
to provide significant and interesting features and, in particular, the choice
of junction conditions dramatically changes the distribution and sizes of stop
bands. Given that flexural vibrations in thin beams are excited more readily
than compressional modes and the ability to model elastic surface waves using
the scalar wave equation (i.e. waves on a membrane), the paper provides new
pathways toward novel experimental set-ups for elastic metasurfaces.",1904.07690v2
2003-01-31,Entanglement of Electron Spin and Orbital States in Spintronic Quantum Transport,"An electron within a mesoscopic (quantum-coherent) spintronic structure is
described by a single wave function which, in the presence of both charge
scattering and spin-orbit coupling, encodes an information about {\em
entanglement} of its spin and orbital degrees of freedom. The quantum state--an
{\em improper} mixture--of experimentally detectable spin subsystem is
elucidated by evaluating quantum information theory measures of entanglement in
the scattering states which determine {\em quantum transport} properties of
spin-polarized electrons injected into a two-dimensional disordered Rashba
spin-split conductor that is attached to the ferromagnetic source and drain
electrodes. Thus, the Landauer transmission matrix, traditionally evaluated to
obtain the spin-resolved conductances, also yields the reduced spin density
operator allowing us to extract quantum-mechanical measures of the detected
electron spin-polarization and spin-coherence, thereby pointing out how to
avoid detrimental {\em decoherence} effects on spin-encoded information
transport through semiconductor spintronic devices.",0301614v3
2012-11-09,Interaction induced staggered spin-orbit order in two-dimensional electron gas,"We propose and formulate an interaction induced staggered spin-orbit order as
a new emergent phase of two-dimensional Fermi gases. We show that when some
form of inherent spin-splitting via Rashba-type spin-orbit coupling renders two
helical Fermi surfaces to become significantly `nested', a Fermi surface
instability arises. To lift this degeneracy, a spontaneous symmetry breaking
spin-orbit density wave develops, causing a surprisingly large quasiparticle
gapping with chiral electronic states. Since the staggered spin-orbit order is
associated with a condensation energy, quantified by the gap value, destroying
such spin-orbit interaction costs sufficiently large perturbation field or
temperature or de-phasing time. BiAg$_2$ surface state is shown to be a
representative system for realizing such novel spin-orbit interaction with
tunable and large strength, and the spin-splitting is decoupled from charge
excitations. These functional properties are relevant for spin-electronics,
spin-caloritronics, and spin-Hall effect applications.",1211.2018v1
2013-08-20,Hole Spin Helix: Anomalous Spin Diffusion in Anisotropic Strained Hole Quantum Wells,"We obtain the spin-orbit interaction and spin-charge coupled transport
equations of a two-dimensional heavy hole gas under the influence of strain and
anisotropy. We show that a simple two-band Hamiltonian can be used to describe
the holes. In addition to the well-known cubic hole spin-orbit interaction,
anisotropy causes a Dresselhaus-like term, and strain causes a Rashba term. We
discover that strain can cause a shifting symmetry of the Fermi surfaces for
spin up and down holes. We predict an enhanced spin lifetime associated with a
spin helix standing wave similar to the Persistent Spin Helix which exists in
the two-dimensional electron gas with equal Rashba and Dresselhaus spin-orbit
interactions. These results may be useful both for spin-based experimental
determination of the Luttinger parameters of the valence band Hamiltonian and
for creating long-lived spin excitations.",1308.4248v3
2016-08-23,The effect of spin-orbit coupling on the effective-spin correlation in YbMgGaO4,"Motivated by the recent experiments on the triangular lattice spin liquid
YbMgGaO$_4$, we explore the effect of spin-orbit coupling on the effective-spin
correlation of the Yb local moments. We point out the anisotropic interaction
between the effective-spins on the nearest neighbor bonds is sufficient to
reproduce the spin-wave dispersion of the fully polarized state in the presence
of strong magnetic field normal to the triangular plane. We further evaluate
the effective-spin correlation within the mean-field spherical approximation.
We explicitly demonstrate that, the nearest-neighbor anisotropic effective-spin
interaction, originating from the strong spin-orbit coupling, enhances the
effective-spin correlation at the M points in the Brillouin zone. We identify
these results as the strong evidence for the anisotropic interaction and the
strong spin-orbit coupling in YbMgGaO$_4$.",1608.06445v2
2016-08-26,RKKY oscillations in the spin relaxation rates of atomic scale nanomagnets,"Exchange interactions with itinerant electrons are known to act as a
relaxation mechanism for individual local spins. The same exchange interactions
are also known to induce the so called RKKY indirect exchange interaction
between two otherwise decoupled local spins. Here we show that both the spin
relaxation and the RKKY coupling can be seen as the dissipative and reactive
response to the coupling of the local spins with the itinerant electrons. We
thereby predict that the spin relaxation rates of magnetic nanostructures of
exchanged coupled local spins, such as as nanoengineered spin chains, have an
oscillatory dependence on $k_F d$ , where $k_F$ is the Fermi wave length and
$d$ is the inter-spin distance, very much like the celebrated oscillations in
the RKKY interaction. We demonstrate that both $T_1$ and $T_2$ can be enhanced
or suppressed, compared to the single spin limit, depending on the interplay
between the Fermi surface and the nanostructure geometrical arrangement. Our
results open a route to engineer spin relaxation and decoherence in atomically
designed spin structures.",1608.07462v2
2019-04-24,Enhanced spin-triplet pairing in magnetic junctions with s-wave superconductors,"A common path to superconducting spintronics, Majorana fermions, and
topologically-protected quantum computing relies on spin-triplet
superconductivity. While naturally occurring spin-triplet pairing is elusive
and even common spin-triplet candidates, such as Sr$_2$RuO$_4$, support
alternative explanations, proximity effects in heterostructures can overcome
these limitations. It is expected that robust spin-triplet superconductivity in
magnetic junctions should rely on highly spin-polarized magnets or complex
magnetic multilayers. Instead, we predict that the interplay of interfacial
spin-orbit coupling and the barrier strength in simple magnetic junctions, with
only a small spin polarization and s-wave superconductors, can lead to nearly
complete spin-triplet superconducting proximity effects. This peculiar behavior
arises from an effective perfect transparency: interfacial spin-orbit coupling
counteracts the native potential barrier for states of a given spin and wave
vector. We show that the enhanced spin-triplet regime is characterized by a
huge increase in conductance magnetoanisotropy, orders of magnitude larger than
in the normal state.",1904.10773v1
2023-01-28,Self-driven Hybrid Atomic Spin Oscillator,"A self-driven hybrid atomic spin oscillator is demonstrated in theory and
experiment with a vapor Rb-Xe dual-spin system. The raw signal of Rb spin
oscillation is amplified, phase-shifted and sent back to drive the Xe spins
coherently. By fine tuning the driving field strength and phase, a
self-sustaining spin oscillation signal with zero frequency shift is obtained.
The effective coherence time is infinitely prolonged beyond the intrinsic
coherence time of Xe spins, forming a hybrid atomic spin oscillator. Spectral
analysis indicates that a frequency resolution of 13.1 nHz is achieved,
enhancing the detection sensitivity for magnetic field. Allan deviation
analysis shows that the spin oscillator can operate in continuous wave mode
like a spin maser. The prototype spin oscillator can be easily implanted into
other hybrid spin systems and enhance the detection sensitivity of alkali
metal-noble gas comagnetometers.",2301.12121v2
2019-08-19,Nonlinear Rossby wave-wave and wave-mean flow theory for long term Solar cycle modulations,"The Schwabe cycle of solar activity exhibits modulations and frequency
fluctuations on slow time scales of centuries and millennia. Plausible physical
explanations for the cause of these long-term variations of the solar cycle are
still elusive, with possible theories including stochasticity of alpha effect
and fluctuations of the differential rotation. It has been suggested recently
in the literature that there exists a possible relation between the
spatio-temporal structure of Solar cycle and the nonlinear dynamics of
magnetohydrodynamic Rossby waves at the solar tachocline, including both
wave-wave and wave-mean flow interactions. Here we extend the nonlinear theory
of MHD Rossby waves presented in a previous article to take into account long
term modulation effects due to a recently discovered mechanism that allows
significant energy transfers throughout different wave triads: the precession
resonance mechanism. We have found a large number of Rossby-Haurwitz wave
triads whose frequency mismatches are compatible with the solar cycle
frequency. Consequently, by analyzing the reduced dynamics of two triads
coupled by a single mode (five-wave system), we have demonstrated that in the
amplitude regime in which precession resonance occurs, the energy transfer
throughout the system yields significant long-term modulations on the main
$\sim 11$yr period associated with intra-triad energy exchanges. We further
show that such modulations display an inverse relationship between the
characteristic wave amplitude and the period of intra-triad energy exchanges,
which is consistent with the Waldmeier's law for the solar cycle. In the
presence of a constant forcing and dissipation, the five-wave system in the
precession resonance regime exhibits irregular amplitude fluctuations with some
periods resembling the Grand Minimum states.",1908.07056v1
1998-06-26,Electron-spin-resonance in the doped spin-Peierls compound Cu(1-x)Ni(x)GeO3,"ESR-study of the Ni-doped spin-Peierls compound CuGeO3 has been performed in
the frequency range 9-75 GHz. At low temperatures the g-factor is smaller than
the value expected for Cu- and Ni-ions. This anomaly is explained by the
formation of magnetic clusters around the Ni-ions within a nonmagnetic
spin-Peierls matrix. The transition into the AFM-state detected earlier by
neutron scattering for doped samples was studied by means of ESR. For x=0.032 a
gap in the magnetic resonance spectrum is found below the Neel temperature and
the spectrum is well described by the theory of antiferromagnetic resonance
based on the molecular field approximation. For x=0.017 the spectrum below the
Neel point remained gapless. The gapless spectrum of the antiferromagnetic
state in weekly doped samples is attributed to the small value of the Neel
order parameter and to the magnetically disordered spin-Peierls background.",9806325v1
2002-12-11,Ferromagnetic resonant tunneling diodes as spin polarimeters and polarizers,"A method for measuring the degree of spin polarization of magnetic materials
based on spin-dependent resonant tunneling is proposed. The device we consider
is a ballistic double-barrier resonant structure consisting of a ferromagnetic
layer embedded between two insulating barriers. A simple procedure, based on a
detailed analysis of the differential conductance, allows to accurately
determine the polarization of the ferromagnet. The spin-filtering character of
such a system is furthermore addressed. We show that a 100% spin selectivity
can be achieved under appropriate conditions. This approach is believed to be
well suited for the investigation of diluted magnetic semiconductor
heterostructures.",0212242v1
2006-12-21,Zero-conductance resonances and spin-filtering effects in ring conductors subject to Rashba coupling,"We investigate the effect of Rashba spin-orbit coupling and of a tunnel
barrier on the zero conduc- tance resonances appearing in a one-dimensional
conducting Aharonov-Bohm (AB) ring symmet- rically coupled to two leads. The
transmission function of the corresponding one-electron problem is derived
within the scattering matrix approach and analyzed in the complex energy plane
with focus on the role of the tunnel barrier strength on the zero-pole
structure characteristic of trans- mission (anti)resonances. The lifting of the
real conductance zeros is related to the breaking of the spin-reversal symmetry
and time-reversal symmetry of Aharonov-Casher (AC)and AB rings, as well as to
rotational symmetry breaking in presence of a tunnel barrier. We show that the
polarization direction of transmitted electrons can be controlled via the
tunnel barrier strength and discuss a novel spin-filtering design in
one-dimensional rings with tunable spin-orbit interaction.",0612560v1
2002-11-12,Spin Response of the Nucleon in the Resonance Region,"I discuss recent results from Jefferson Lab on the measurement of inclusive
spin structure functions in the nucleon resonance region using polarized
electron beams and polarized targets. Results on the first moment of the spin
structure function for protons and neutrons are discussed, as well as the
Bjorken integral. I will argue that the helicity structure of individual
resonances plays a vital role in understanding the nucleon's spin response in
the domain of strong interaction QCD, and must be considered in any analysis of
the nucleon spin structure at low and intermediate photon virtuality.",0211185v1
2007-06-01,Spin Effect on the Resonant Tunneling Characteristics of a Double-Barrier Heterostructures Under Longitudinal Stresses,"Theoretical research on electronic properties in mesoscopic condensed matter
systems has focused primarily on the electron charge freedom degrees, while its
corresponding spin freedom degrees have not yet received the same attention.
Nevertheless nowadays there has been an increment in the number of electron
spin-related experiments showing unique possibilities for finding novel
mechanisms of information processing and transmission, opening ample fields of
opportunities in the theoretical developed of new models. In this spirit we
have calculated the resonant tunneling characteristics curves in double-barrier
heterostructures of GaAs-Ga1-x AlxAs under external stress and considering two
charges with spin half. The resonant tunneling study has been carried out by
means of the diagrammatic techniques for non equilibrium processes following
the model proposed by Keldysh also a simple one-band tight-binding Hamiltonian
is adopted in the theoretical framework. We have compared our results of the
spin-tunneling with previous ones reported in literature.",0706.0177v1
2007-07-24,Pauli-Spin-Blockade Transport through a Silicon Double Quantum Dot,"We present measurements of resonant tunneling through discrete energy levels
of a silicon double quantum dot formed in a thin silicon-on-insulator layer. In
the absence of piezoelectric phonon coupling, spontaneous phonon emission with
deformation-potential coupling accounts for inelastic tunneling through the
ground states of the two dots. Such transport measurements enable us to observe
a Pauli spin blockade due to effective two-electron spin-triplet correlations,
evident in a distinct bias-polarity dependence of resonant tunneling through
the ground states. The blockade is lifted by the excited-state resonance by
virtue of efficient phonon emission between the ground states. Our experiment
demonstrates considerable potential for investigating silicon-based spin
dynamics and spin-based quantum information processing.",0707.3513v2
2007-12-02,Spin resonance in the d-wave superconductor CeCoIn5,"Neutron scattering is used to probe antiferromagnetic spin fluctuations in
the d-wave heavy fermion superconductor CeCoIn$_{5}$ (T$_{c}$=2.3 K).
Superconductivity develops from a state with slow ($\hbar\Gamma$=0.3 $\pm$ 0.15
meV) commensurate (${\bf{Q_0}}$=(1/2,1/2,1/2)) antiferromagnetic spin
fluctuations and nearly isotropic spin correlations. The characteristic
wavevector in CeCoIn$_{5}$ is the same as CeIn$_{3}$ but differs from the
incommensurate wavevector measured in antiferromagnetically ordered
CeRhIn$_{5}$. A sharp spin resonance ($\hbar\Gamma<0.07$ meV) at $\hbar \omega$
= 0.60 $\pm$ 0.03 meV develops in the superconducting state removing spectral
weight from low-energy transfers. The presence of a resonance peak is
indicative of strong coupling between f-electron magnetism and
superconductivity and consistent with a d-wave gap order parameter satisfying
$\Delta({\bf q+Q_0})=-\Delta({\bf q})$.",0712.0172v1
2008-02-28,Physical Programm and Acceleration of Polarized Light Nuclei Beams at Jinr Nuclotron,"The physical spin program at high $p_T$ region and energies $s^{1/2}_{NN}
\sim 10 GeV$ is discussed. It's shown that cumulative processes, color
transparency problem and polarization phenomenons directly connect with
properties new form of the nuclear matter as Color Quark Condensate(CQC).
Studies of CQC one of the most important physical problem and can be realized
using polarized ion beams at JINR nuclotron-M (and in future at NICA). The
calculations of spin resonance strengthes in the linear approximation for p, d,
t and $^3He$ beams in the JINR nuclotron are presented. The methods to preserve
the degree of polarization during crossing the spin resonances are examined.
The method of matching the direction of polarization vector during the beam
injection in to the ring of the nuclotron is given. These methods of spin
resonance crossing can be used to accelerate polarized beams in the other
cyclic accelerators.",0802.4153v1
2010-10-28,Quantum Dot Spin Filter in Resonant Tunneling and Kondo Regimes,"A quantum dot with spin-orbit interaction can work as an efficient spin
filter if it is connected to N (> 2) external leads via tunnel barriers. When
an unpolarized current is injected to a quantum dot from a lead, polarized
currents are ejected to other leads. A two-level quantum dot is examined as a
minimal model. First, we show that the spin polarization is markedly enhanced
by resonant tunneling when the level spacing in the dot is smaller than the
level broadening. Next, we examine the many-body resonance induced by the Kondo
effect in the Coulomb blockade regime. A large spin current is generated in the
presence of the SU(4) Kondo effect when the level spacing is less than the
Kondo temperature.",1010.5956v2
2011-01-27,Modes of magnetic resonance in the spin liquid phase of Cs2CuCl4,"We report the observation of a frequency shift and splitting of the electron
spin resonance (ESR) mode of the low-dimensional S=1/2 frustrated
antiferromagnet Cs2CuCl4 in the spin-correlated state below the Curie-Weiss
temperature 4 K but above the ordering temperature 0.62 K. The shift and
splitting exhibit strong anisotropy with respect to the direction of the
applied magnetic field and do not vanish in zero field. The low-temperature
evolution of spin resonance response is a result of the specific modification
of one-dimensional spinon continuum under the action of the uniform
Dzyaloshinskii-Moriya interaction (DM) within the spin chains. Parameters of
the uniform DM interaction are derived from the experiment.",1101.5275v1
2011-03-07,Polariton spin Faraday rotation dynamics in a GaAs microcavity,"Polariton spin carries the combination of the exciton and the photon spin,
which is manifested in the circularly polarized emission degree in a III-V
quantum wells microcavity system. Relaxation process of such spin system is a
complex subject since it involve upper or lower polariton branch, resonant or
non resonant polariton excitation process and if the particles are in strong or
weak coupling regime. We present here experimental polariton spin Faraday
rotation time measurement in GaAs single quantum well microcavity, using time
resolved polariton photoluminescence by resonant excitation process in a
pump-probe system.",1103.1337v2
2011-09-02,Measurement of statistical nuclear spin polarization in a nanoscale GaAs sample,"We measure the statistical polarization of quadrupolar nuclear spins in a
sub-micrometer (0.6 um^3) particle of GaAs using magnetic resonance force
microscopy. The crystalline sample is cut out of a GaAs wafer and attached to a
micro-mechanical cantilever force sensor using a focused ion beam technique.
Nuclear magnetic resonance is demonstrated on ensembles containing less than 5
x 10^8 nuclear spins and occupying a volume of around (300 nm)^3 in GaAs with
reduced volumes possible in future experiments. We discuss how the further
reduction of this detection volume will bring the spin ensemble into a regime
where random spin fluctuations, rather than Boltzmann polarization, dominate
its dynamics. The detection of statistical polarization in GaAs therefore
represents an important first step toward 3D magnetic resonance imaging of
III-V materials on the nanometer-scale.",1109.0411v2
2012-07-25,High cooperativity in coupled microwave resonator ferrimagnetic insulator hybrids,"We report the observation of strong coupling between the exchange-coupled
spins in gallium-doped yttrium iron garnet and a superconducting coplanar
microwave resonator made from Nb. The measured coupling rate of 450 MHz is
proportional to the square-root of the number of exchange-coupled spins and
well exceeds the loss rate of 50 MHz of the spin system. This demonstrates that
exchange coupled systems are suitable for cavity quantum electrodynamics
experiments, while allowing high integration densities due to their
extraordinary high spin densities. Our results furthermore show, that
experiments with multiple exchange-coupled spin systems interacting via a
single resonator are within reach.",1207.6039v2
2013-03-02,Nuclear-spin-dependent coherent population trapping of single nitrogen vacancy centers in diamond,"Coherent population trapping (CPT) provides a highly sensitive means for
probing the energy level structure of an atomic system. For a nitrogen vacancy
center in diamond, the CPT offers an alternative to the standard
optically-detected magnetic resonance method for measuring the hyperfine
structure of the electronic ground states. We show that the nuclear spin
dependent CPT measures directly the hyperfine splitting of these states due to
the 14N nuclear spin. The CPT spectral response obtained in the presence of a
strong microwave field, resonant or nearly resonant with a ground state spin
transition, maps out the dynamic Stark splitting induced by the coherent spin
excitation.",1303.0421v1
2013-05-10,Observation of conduction electron spin resonance in boron doped diamond,"We observe the electron spin resonance of conduction electrons in boron doped
(6400 ppm) superconducting diamond (Tc =3.8 K). We clearly identify the
benchmarks of conduction electron spin resonance (CESR): the nearly temperature
independent ESR signal intensity and its magnitude which is in good agreement
with that expected from the density of states through the Pauli
spin-susceptibility. The temperature dependent CESR linewidth weakly increases
with increasing temperature which can be understood in the framework of the
Elliott-Yafet theory of spin-relaxation. An anomalous and yet unexplained
relation is observed between the g-factor, CESR linewidth, and the resistivity
using the empirical Elliott-Yafet relation.",1305.2366v1
2014-02-28,Simulating systems of itinerant spin-carrying particles using arrays of superconducting qubits and resonators,"We propose possible approaches for the quantum simulation of itinerant
spin-carrying particles in a superconducting qubit-resonator array. The
standard Jaynes-Cummings-Hubbard setup considered in several recent studies can
readily be used as a quantum simulator for a number of relevant phenomena,
including the interaction with external magnetic fields and spin-orbit
coupling. A more complex setup where multiple qubits and multiple resonator
modes are utilized in the simulation gives a higher level of complexity,
including the simulation of particles with high spin values and allowing more
direct control on processes related to spin-orbit coupling. This proposal could
be implemented in state-of-the-art superconducting circuits in the near future.",1402.7185v2
2015-02-02,Resonant magneto-tunneling between normal and ferromagnetic electrodes in relation to the three-terminal spin transport,"The recently suggested mechanism [Y. Song and H. Dery, Phys. Rev. Lett. 113,
047205 (2014)] of the three-terminal spin transport is based on the resonant
tunneling of electrons between ferromagnetic and normal electrodes via an
impurity. The sensitivity of current to a weak external magnetic field stems
from a spin blockade, which, in turn, is enabled by strong on-site repulsion.
We demonstrate that this sensitivity exists even in the absence of repulsion
when a single-particle description applies. Within this description, we
calculate exactly the resonant-tunneling current between the electrodes. The
mechanism of magnetoresistance, completely different from the spin blocking,
has its origin in the interference of virtual tunneling amplitudes. Spin
imbalance in ferromagnetic electrode is responsible for this interference and
the resulting coupling of the Zeeman levels. This coupling also affects the
current in the correlated regime.",1502.00350v1
2015-10-05,Resonant Spin and Charge Hall Effects in 2D Electron Gas with Unequal Rashba and Dresselhaus Spin-Orbit Couplings under a Perpendicular Magnetic Field,"We have investigated the complex two-dimensional electron system with unequal
Rashba and Dresselhaus spin-orbit interactions in the presence of a
perpendicular magnetic field. The spin polarizations are obtained in a wide
range of magnetic fields. It is shown that such a system is hard to be
magnetized. We also find that the resonant charge and spin Hall conductances
occurs simultaneously at a certain magnetic field, at which two (nearly)
degenerate Landau levels are filled partly. The resonant Hall effects are
universal in this type of semiconductor materials, and could have potential
application for semiconductor spintronics.",1510.01012v1
2015-11-25,Ferromagnetic resonance phase imaging in spin Hall multilayers,"We experimentally image the magnetic precession phase of patterned spin Hall
multilayer samples to study the rf driving field vector using time-resolved
anomalous Nernst effect (TRANE) microscopy. Our ferromagnetic resonance (FMR)
measurements quantify the phase and amplitude for both the magnetic precession
and the electric current, which allows us to establish the total driving field
orientation and the strength of spin Hall effect. In a channel of uniform
width, we observe spatial variation of the FMR phase laterally across the
channel. We interpret our findings in the context of electrical measurement
using the spin-transfer torque ferromagnetic resonance technique and show that
observed phase variation introduces a systematic correction into the spin Hall
angle if spatial phase and amplitude variations are not taken into account.",1511.08126v1
2015-11-27,Resonance spin-charge phenomena and mechanism of magnetoresistance anisotropy in manganite/metal bilayer structures,"The dc voltage generated under ferromagnetic resonance has been studied in
bilayer structures based on manganite thin epitaxial films La0.67Sr0.33MnO3
(LSMO) and non-magnetic metals (Au, Pt, and SrRuO3) in the temperature range up
to the Curie point. The effect is shown to be caused by two different
phenomena: (1) the resonance dc electromotive force related to anisotropic
magnetoresistance (AMR) in the manganite film and (2) pure spin current (spin
pumping) registered by means of the inverse spin Hall effect in normal metal.
The two phenomena were separated using the angular dependence of the effect,
the external magnetic field H0 being rotated in the film plane. It was found
that the AMR mechanism in the manganite films differs substantially from that
in traditional ferromagnetic metals being governed by the colossal
magnetoresistance together with the in-plane magnetic anisotropy. The spin
pumping effect registered in the bilayers was found to be much lower than that
reported for common ferromagnets; possible reasons are discussed.",1511.08664v1
2015-11-17,Fingerprints of entangled spin and orbital physics in itinerant ferromagnets via angle resolved $resonant$ photoemission,"A novel method for mapping the local spin and orbital nature of the ground
state of a system via corresponding flip excitations in both sectors is
proposed based on angle resolved resonant photoemission and related diffraction
patterns, presented here for the first time via an ab-initio modified one-step
theory of photoemission. The analysis is done on the paradigmatic weak
itinerant ferromagnet bcc Fe, whose magnetism, seen as a correlation phenomenon
given by the coexistence of localized moments and itinerant electrons, and the
non-Fermi liquid behaviour at ambient and extreme conditions both remain
unclear. The results offer a real space imaging of local pure spin flip and
entangled spin flip-orbital flip excitations (even at energies where spin flip
transitions are hidden in quasiparticle peaks) and of chiral, vortex-like
wavefronts of excited electrons, depending on the orbital character of the
bands and the direction of the local magnetic moment. Such effects, mediated by
the hole polarization, make resonant photoemission a promising tool to perform
a full tomography of the local magnetic properties of a system with a high
sensitivity to localization/correlation, even in itinerant or macroscopically
non magnetic systems.",1604.07767v1
2016-05-10,Electric-field-induced interferometric resonance of a one-dimensional spin-orbit-coupled electron,"We consider a one-dimensional spin-orbit-coupled nanowire quantum dot, driven
by external electric and magnetic fields, and theoretically formulate an
electric mechanism to interfere its electron orbits. Owing to the existence of
spin-orbit coupling and a pulsed electric field, different spin-orbit states
are shown to interfere with each other, generating intriguing
interference-resonant patterns. We also reveal that an in-plane magnetic field
does not affect the strength interval of any neighboring resonant peaks, but
contributes a weak shift of each peak, which is sensitive to the direction of
the magnetic field. We find that this proposed external-field-controlled scheme
should be regarded as a new type of quantum-dot-based interferometry. Finally,
this interferometry has an important application in precisely measuring
relative experimental parameters, such as the Rashba and Dresselhaus
spin-orbit-coupling strengths, as well as the Lande-g factor.",1605.02871v3
2016-07-14,Simultaneous Measurement of Resistively and Optically Detected Nuclear Magnetic Resonance in the $ν=2/3$ Fractional Quantum Hall Regime,"We observe nuclear magnetic resonance (NMR) in the fractional quantum Hall
regime at Landau level filling factor $\nu=2/3$ from simultaneous measurement
of longitudinal resistance and photoluminescence (PL). The dynamic nuclear spin
polarization is induced by applying a huge electronic current at the spin phase
transition point of $\nu=2/3$. The NMR spectra obtained from changes in
resistance and PL intensity are qualitatively the same; that is, the Knight
shift (spin polarized region) and zero-shift (spin unpolarized region)
resonances are observed in both. The observed change in PL intensity is
interpreted as a consequence of the trion scattering induced by polarized
nuclear spins. We conclude that both detection methods probe almost the same
local phenomena.",1607.04094v1
2016-08-10,Creating arbitrary quantum vibrational states in a carbon nanotube,"We theoretically study the creation of single- and multi-phonon Fock states
and arbitrary superpositions of quantum phonon states in a nanomechanical
carbon nanotube (CNT) resonator. In our model, a doubly clamped CNT resonator
is initialized in the ground state and a single electron is trapped in a
quantum dot which is formed by a electric gate potential and brought into the
magnetic field of a micro-magnet. The preparation of arbitrary quantum phonon
states is based on the coupling between the mechanical motion of the CNT and
the electron spin which acts as a non-linearity. We assume that electrical
driving pulses with different frequencies are applied on the system. The
quantum information is transferred from the spin qubit to the mechanical motion
by the spin-phonon coupling and the electron spin qubit can be reset by the
single-electron spin resonance. We describe Wigner tomography which can be
applied at the end to obtain the phase information of the prepared phonon
states.",1608.03068v1
2016-10-27,Spin transfer driven resonant expulsion of a magnetic vortex core for efficient rf detector,"Spin transfer magnetization dynamics have led to considerable advances in
Spintronics, including opportunities for new nanoscale radiofrequency devices.
Among the new functionalities is the radiofrequency(rf) detection using the
spin diode rectification effect in spin torque nano-oscillators (STNOs). In
this study, we focus on a new phenomenon, the resonant expulsion of a magnetic
vortex in STNOs. This effect is observed when the excitation vortex radius, due
to spin torques associated to rf currents, becomes larger than the actual
radius of the STNO. This vortex expulsion is leading to a sharp variation of
the voltage at the resonant frequency. Here we show that the detected frequency
can be tuned by different parameters; furthermore, a simultaneous detection of
different rf signals can be achieved by real time measurements with several
STNOs having different diameters. This result constitutes a first
proof-of-principle towards the development of a new kind of nanoscale rf
threshold detector.",1610.08660v1
2018-09-07,Spin-Conserving Resonant Tunneling in Twist-Controlled WSe2-hBN-WSe2 Heterostructures,"We investigate interlayer tunneling in heterostructures consisting of two
tungsten diselenide (WSe2) monolayers with controlled rotational alignment, and
separated by hexagonal boron nitride. In samples where the two WSe2 monolayers
are rotationally aligned we observe resonant tunneling, manifested by a large
conductance and negative differential resistance in the vicinity of zero
interlayer bias, which stem from energy- and momentum-conserving tunneling.
Because the spin-orbit coupling leads to coupled spin-valley degrees of
freedom, the twist between the two WSe2 monolayers allows us to probe the
conservation of spin-valley degree of freedom in tunneling. In heterostructures
where the two WSe2 monolayers have a 180{\deg} relative twist, such that the
Brillouin zone of one layer is aligned with the time-reversed Brillouin zone of
the opposite layer, the resonant tunneling between the layers is suppressed.
These findings provide evidence that in addition to momentum, the spin-valley
degree of freedom is also conserved in vertical transport.",1809.02639v1
2017-05-09,Local optical control of the resonant dipole-dipole interaction between Rydberg atoms,"We report on the local control of the transition frequency of a spin-$1/2$
encoded in two Rydberg levels of an individual atom by applying a
state-selective light shift using an addressing beam. With this tool, we first
study the spectrum of an elementary system of two spins, tuning it from a
non-resonant to a resonant regime, where ""bright"" (superradiant) and ""dark""
(subradiant) states emerge. We observe the collective enhancement of the
microwave coupling to the bright state. We then show that after preparing an
initial single spin excitation and letting it hop due to the spin-exchange
interaction, we can freeze the dynamics at will with the addressing laser,
while preserving the coherence of the system. In the context of quantum
simulation, this scheme opens exciting prospects for engineering inhomogeneous
XY spin Hamiltonians or preparing spin-imbalanced initial states.",1705.03293v1
2017-02-06,Spin resonance under topological driving fields,"We study the dynamics of a localized spin-1/2 driven by a time-periodic
magnetic field that undergoes a topological transition. Despite the strongly
non-adiabatic effects dominating the spin dynamics, we find that the field's
topology appears clearly imprinted in the Floquet spin states through an
effective Berry phase emerging in the quasienergy. This has remarkable
consequences on the spin resonance condition suggesting a whole new class of
experiments to spot topological transitions in the dynamics of spins and other
two-level systems, from nuclear magnetic resonance to strongly-driven
superconducting qubits.",1702.01781v2
2020-09-01,Mapping the stray fields of a nanomagnet using spin qubits in SiC,"We report the use of optically addressable spin qubits in SiC to probe the
magnetic stray fields generated by a ferromagnetic microstructure
lithographically patterned on the surface of a SiC crystal. The stray fields
cause shifts in the resonance frequency of the spin centers. The spin resonance
is driven by a micrometer-sized microwave antenna patterned adjacent to the
magnetic element. The patterning of the antenna is done to ensure that the
driving microwave fields are delivered locally and more efficiently compared to
conventional, millimeter-sized circuits. A clear difference in the resonance
frequency of the spin centers in SiC is observed at various distances to the
magnetic element, for two different magnetic states. Our results offer a
wafer-scale platform to develop hybrid magnon-quantum applications by deploying
local microwave fields and the stray field landscape at the micrometer
lengthscale.",2009.00347v1
2020-09-15,Pulsed Electron Spin Resonance of an Organic Microcrystal by Dispersive Readout,"We establish a testbed system for the development of high-sensitivity
Electron Spin Resonance (ESR) techniques for small samples at cryogenic
temperatures. Our system consists of a Niobium Nitride thin-film planar
superconducting microresonator designed to have a concentrated mode volume to
couple to a small amount of paramagnetic material, and to be resilient to
magnetic fields of up to 400 mT. At 65 mK we measure high-cooperativity
coupling ($C \approx 19$) to an organic radical microcrystal containing
$10^{12}$ spins in a pico-litre volume. We detect the spin-lattice decoherence
rate via the dispersive frequency shift of the resonator. Techniques such as
these could be suitable for applications in quantum information as well as for
pulsed ESR interrogation of very few spins and could provide insights into the
surface chemistry of, for example, the material defects in superconducting
quantum processors.",2009.06933v2
2020-11-05,Magnetoacoustic Resonance to Probe Quadrupole-Strain Coupling in a Diamond Nitrogen-Vacancy Center as a Spin-Triplet System,"A theory of magnetoacoustic resonance is proposed to measure
quadrupole-strain couplings in a spin-triplet state with the $C_{3v}$ point
group symmetry, considering the spin-strain interaction in a diamond
nitrogen-vacancy (NV) center. Based on the Floquet theory, we demonstrate how
the single- and two-phonon transition probabilities depend on the change in the
longitudinal and transverse quadrupole couplings, which can be controlled by
rotating an applied magnetic field, around the threefold axis. The obtained
quadrupole dynamics results are useful for realizing mechanical or ac
strain-control of the NV spin as an alternative to the conventional magnetic
control by spin resonance.",2011.02703v1
2017-03-15,Amplitude sensing below the zero-point fluctuations with a two-dimensional trapped-ion mechanical oscillator,"We present a technique to measure the amplitude of a center-of-mass (COM)
motion of a two-dimensional ion crystal of $\sim$100 ions. By sensing motion at
frequencies far from the COM resonance frequency, we experimentally determine
the technique's measurement imprecision. We resolve amplitudes as small as 50
pm, 40 times smaller than the COM mode zero-point fluctuations. The technique
employs a spin-dependent, optical-dipole force to couple the mechanical
oscillation to the electron spins of the trapped ions, enabling a measurement
of one quadrature of the COM motion through a readout of the spin state. We
demonstrate sensitivity limits set by spin projection noise and spin
decoherence due to off-resonant light scattering. When performed on resonance
with the COM mode frequency, the technique demonstrated here can enable the
detection of extremely weak forces ($< \,$1 yN) and electric fields ($< \,$1
nV/m), providing an opportunity to probe quantum sensing limits and search for
physics beyond the standard model.",1703.05369v2
2019-01-15,"SiC-YiG X band quantum sensor for sensitive surface paramagnetic resonance applied to chemistry, biology, physics","Here I present the SiC-YiG Quantum Sensor, allowing electron paramagnetic
resonance (EPR) studies of monolayer or few nanometers thick chemical,
biological or physical samples located on the sensor surface. It contains two
parts, a 4H-SiC substrate with many paramagnetic silicon vacancies (V2) located
below its surface, and YIG ferrimagnetic nanostripes. Spins sensing properties
are based on optically detected double electron-electron spin resonance under
the strong magnetic field gradient of nanostripes. Here I describe fabrication,
magnetic, optical and spins sensing properties of this sensor. I show that the
target spins sensitivity is at least five orders of magnitude larger than the
one of standard X band EPR spectrometer, for which it constitutes, combined
with a fiber bundle, a powerful upgrade for sensitive surface EPR. This sensor
can determine the target spins planes EPR spectrum, their positions with a
nanoscale precision of +/- 1 nm, and their 2D concentration down to
1/(20nm.20nm).",1901.05073v1
2019-09-06,Strong Spin Resonance Mode associated with suppression of soft magnetic ordering in Hole-doped Ba1-xNaxFe2As2,"Spin-resonance modes (SRM) are taken as evidence for magnetically driven
pairing in Fe-based superconductors, but their character remains poorly
understood. The broadness, the splitting and the spin-space anisotropies of
SRMs contrast with the mostly accepted interpretation as spin excitons. We
study hole-doped Ba$_{1-x}$Na$_x$Fe$_2$As$_2$ that displays a spin
reorientation transition. This reorientation has little impact on the overall
appearance of the resonance excitations with a high-energy isotropic and a
low-energy anisotropic mode. However, the strength of the anisotropic
low-energy mode sharply peaks at the highest doping that still exhibits
magnetic ordering resulting in the strongest SRM observed in any Fe-based
superconductor so far. This remarkably strong SRM is accompanied by a loss of
about half of the magnetic Bragg intensity upon entering the SC phase.
Anisotropic SRMs thus can allow the system to compensate for the loss of
exchange energy arising from the reduced antiferromagnetic correlations within
the SC state.",1909.03046v1
2022-01-08,Spin to charge conversion at Rashba-split SrTiO$_3$ interfaces from resonant tunneling,"Spin-charge interconversion is a very active direction in spintronics. Yet,
the complex behaviour of some of the most promising systems such as SrTiO$_3$
(STO) interfaces is not fully understood. Here, on the basis of a 6-band
$\boldsymbol{k.p}$ method combined with spin-resolved scattering theory, we
give a theoretical demonstration of transverse spin-charge interconversion
physics in STO Rashba interfaces. Calculations involve injection of spin
current from a ferromagnetic contact by resonant tunneling into the native
Rashba-split resonant levels of the STO triangular quantum well. We compute an
asymmetric tunneling electronic transmission yielding a transverse charge
current flowing in plane, with a dependence with gate voltage in a very good
agreement with existing experimental data.",2201.02898v1
2022-02-15,Analysis of the robustness and dynamics of spin-locking preparations for the detection of oscillatory magnetic fields,"Extracting quantitative information of neuronal signals by non-invasive
imaging is an outstanding challenge for understanding brain function and
pathology. However, state-of-the-art techniques offer low sensitivity to deep
electrical sources. Stimulus induced rotary saturation (SIRS) is a recently
proposed magnetic resonance imaging (MRI) sequence that detects oscillatory
magnetic fields using a spin-lock preparation. Phantom experiments and
simulations proved its efficiency and sensitivity, but the susceptibility of
the method to field inhomogeneities is still not well understood. In this
study, we simulated and analyzed the dynamic of three spin-lock preparations
and their response to field inhomogeneities in the presence of a resonant
oscillating field. We show that the composite spin-lock preparation is more
robust against field variations within the double resonance effect. In
addition, we tested the capability of the chosen composite spin-lock
preparation to recover information about the spectral components of a composite
signal. This study sets the bases to move one step further towards the clinical
application of MR-based neuronal current imaging.",2202.07705v2
2022-06-09,Spin echo silencing using a current-biased frequency-tunable resonator,"The ability to control microwave emission from a spin ensemble is a
requirement of several quantum memory protocols. Here, we demonstrate such
ability by using a resonator whose frequency can be rapidly tuned with a bias
current. We store excitations in an ensemble of rare-earth-ions and suppress
on-demand the echo emission (`echo silencing') by two methods: 1) detuning the
resonator during the spin rephasing, and 2) subjecting spins to magnetic field
gradients generated by the bias current itself. We also show that spin
coherence is preserved during silencing.",2206.04488v1
2023-01-09,X-ray detected ferromagnetic resonance techniques for the study of magnetization dynamics,"Element-specific spectroscopies using synchrotron-radiation can provide
unique insights into materials properties. The recently developed technique of
X-ray detected ferromagnetic resonance (XFMR) allows studying the magnetization
dynamics of magnetic spin structures. Magnetic sensitivity in XFMR is obtained
from the X-ray magnetic circular dichroism (XMCD) effect, where the phase of
the magnetization precession of each magnetic layer with respect to the
exciting radio frequency is obtained using stroboscopic probing of the spin
precession. Measurement of both amplitude and phase response in the magnetic
layers as a function of bias field can give a clear signature of spin-transfer
torque (STT) coupling between ferromagnetic layers due to spin pumping. Over
the last few years, there have been new developments utilizing X-ray scattering
techniques to reveal the precessional magnetization dynamics of ordered spin
structures in the GHz frequency range. The techniques of diffraction and
reflectometry ferromagnetic resonance (DFMR and RFMR) provide novel ways for
the probing of the dynamics of chiral and multilayered magnetic materials,
thereby opening up new pathways for the development of high-density and
low-energy consumption data processing solutions.",2301.03256v1
2002-03-21,Cu nuclear spin-spin coupling in the dimer singlet state in SrCu2(BO3)2,"We report results of nuclear magnetic resonance (NMR) experiments in
SrCu2(BO3)2, a quasi two-dimensional spin system with a singlet ground state.
When magnetic field is applied along the c-axis, each of the quadrupole split
Cu resonance lines splits further into four lines. The spin-echo intensity for
some of the split lines oscillates against the separation time between the
pai/2 and the pai rf-pulses. These phenomena are due to strong nuclear
spin-spin coupling mediated by the electronic spin system, which exists only
within a pair of nuclei. Thus the results provides direct evidence for the
dimer singlet gorund state in this material.",0203426v1
2002-10-10,Spin-Dependent Transport Through An Interacting Quantum Dot,"We study the nonequilibrium spin transport through a quantum dot containing
two spin levels coupled to the magnetic electrodes. A formula for the
spin-dependent current is obtained and is applied to discuss the linear
conductance and magnetoresistance in the interacting regime, where the
so-called Kondo effect arises. We show that the Kondo resonance and the
correlation-induced spin splitting of the dot levels may be systematically
controlled by internal magnetization in the electrodes. As a result, when the
electrodes are in parallel magnetic configuration, the linear conductance is
characterized by two spin-resolved peaks. Furthermore, the presence of the
spin-flip process in the dot splits the Kondo resonance into three peaks.",0210241v1
2004-06-18,Controlling the Spin Polarization of the Electron Current in a Semimagnetic Resonant-Tunneling Diode,"The spin filtering effect of the electron current in a double-barrier
resonant-tunneling diode (RTD) consisting of ZnMnSe semimagnetic layers has
been studied theoretically. The influence of the distribution of the magnesium
ions on the coefficient of the spin polarization of the electron current has
been investigated. The dependence of the spin filtering degree of the electron
current on the external magnetic field and the bias voltage has been obtained.
The effect of the total spin polarization of the electron current has been
predicted. This effect is characterized by total suppression of the spin-up
component of electron current, that takes place when the Fermi level coincides
with the lowest Landau level for spin-up electrons in the RTD semimagnetic
emitter.",0406434v1
2004-08-20,Probing Single-Electron Spin Decoherence in Quantum Dots using Charged Excitons,"We propose to use optical detection of magnetic resonance (ODMR) to measure
the decoherence time T_{2} of a single electron spin in a semiconductor quantum
dot. The electron is in one of the spin 1/2 states and a circularly polarized
laser can only create an optical excitation for one of the electron spin states
due to Pauli blocking. An applied electron spin resonance (ESR) field leads to
Rabi spin flips and thus to a modulation of the photoluminescence or,
alternatively, of the photocurrent. This allows one to measure the ESR
linewidth and the coherent Rabi oscillations, from which the electron spin
decoherence can be determined. We study different possible schemes for such an
ODMR setup, including cw or pulsed laser excitation.",0408451v1
2006-12-05,Spin gap behavior in Cu$_2$Sc$_2$Ge$_4$O$_{13}$ by $^{45}$Sc nuclear magnetic resonance,"We report the results of a $^{45}$Sc nuclear magnetic resonance (NMR) study
on the quasi-one-dimensional compound Cu$_2$Sc$_2$Ge$_4$O$_{13}$ at
temperatures between 4 and 300 K. This material has been a subject of current
interest due to indications of spin gap behavior. The temperature-dependent NMR
shift exhibits a character of low-dimensional magnetism with a negative broad
maximum at $T_{max}$ $\simeq $ 170 K. Below $% T_{max}$, the NMR shifts and
spin lattice relaxation rates clearly indicate activated responses, confirming
the existence of a spin gap in Cu$_2$Sc$_2$Ge% $_4$O$_{13}$. The experimental
NMR data can be well fitted to the spin dimer model, yielding a spin gap value
of about 275 K which is close to the 25 meV peak found in the inelastic neutron
scattering measurement. A detailed analysis further points out that the nearly
isolated dimer picture is proper for the understanding of spin gap nature in
Cu$_2$Sc$_2$Ge$_4$O$_{13}$.",0612106v1
2007-02-05,Nuclear spin population and its control toward initialization using an all-electrical sub-micron scale nuclear magnetic resonance device,"We study the nuclear spin population in a GaAs quantum well structure and
demonstrate its initialization using an all-electrical nuclear magnetic
resonance (NMR) device. In our device, nuclear spins are dynamically polarized
in a sub-micron scale region defined by split gates. The nuclear spin
populations under various polarization conditions are estimated from
resistively-detected pulsed NMR spectra. We find that nuclear spin populations
are determined by electron spin configurations. By applying radio frequency
pulses to the strongly polarized nuclear spins, we demonstrate the creation of
two-qubit effective pure states, which is a crucial step toward NMR quantum
computation.",0702086v1
2006-07-25,Electrical detection of 31P spin quantum states,"In recent years, a variety of solid-state qubits has been realized, including
quantum dots, superconducting tunnel junctions and point defects. Due to its
potential compatibility with existing microelectronics, the proposal by Kane
based on phosphorus donors in Si has also been pursued intensively. A key issue
of this concept is the readout of the P quantum state. While electrical
measurements of magnetic resonance have been performed on single spins, the
statistical nature of these experiments based on random telegraph noise
measurements has impeded the readout of single spin states. In this letter, we
demonstrate the measurement of the spin state of P donor electrons in silicon
and the observation of Rabi flops by purely electric means, accomplished by
coherent manipulation of spin-dependent charge carrier recombination between
the P donor and paramagnetic localized states at the Si/SiO2 interface via
pulsed electrically detected magnetic resonance. The electron spin information
is shown to be coupled through the hyperfine interaction with the P nucleus,
which demonstrates the feasibility of a recombination-based readout of nuclear
spins.",0607178v1
2008-03-07,Optical-phonon mediated exciton energy relaxation with highly preserved spin states Optical-phonon mediated exciton energy relaxation with highly preserved spin states in a single quantum dot,"High degree of preservation of spin states during energy relaxation processes
mediated by optical phonons is demonstrated in a single quantum dot.
Optical-phonon resonance and relevant suppression of spin relaxation are
clearly identified as dip structures in photoluminescence excitation spectra
probed by the positive trion emission. The absence of continuum states makes
this observation possible under the cross-circularly polarized detection with
respect to a circularly polarized pumping. Consequently, distinguishably high
degree of circular polarization up to ~0.85 is achieved without applying
external magnetic field at the optical-phonon resonance. Rate equation analysis
reveals that the spin-flip probability during energy relaxation is restricted
to less than 7.5%. It is also indicated that the spin flip time of the positive
trion ground state is extended by more than 3 times compared with that of
neutral exciton ground state. This corresponds to the spin flip time longer
than 11 ns for the positive trion ground state. The influence of nuclear
polarization to the present measurements is also discussed.",0803.1037v1
2008-04-11,Scalar and spin-dependent relativistic effects on magnetic properties calculated with four-component methods: the nuclear magnetic resonance parameters of the lead halides,"The results of calculations of nuclear magnetic resonance (NMR) parameters
for the lead halides is reported in this paper. The results are obtained by
using four-component methods. The use of the nonrelativistic L\'evy-Leblond
Hamiltonian along with the relativistic Dirac-Coulomb and spin-free ones allows
us to discriminate scalar and spin-dependent effects on the parameters. It is
found that the wide range of the lead NMR spectra and their large anisotropies
are, mainly, due to spin-dependent effects on the paramagnetic term. Among the
relativistic scalar corrections, the so-called spin-Zeeman kinetic-energy term
turns out to be dominant. The reduced spin-spin coupling constants become
proportional to the product of the atomic numbers of the coupled nuclei.",0804.1952v1
2008-12-02,A Non-Demolition Single Spin Meter,"We present the theory of a single spin meter consisting of a quantum dot in a
magnetic field under microwave irradiation combined with a charge counter. We
show that when a current is passed through the dot, a change in the average
occupation number occurs if the microwaves are resonant with the on-dot Zeeman
splitting. The width of the resonant change is given by the microwave induced
Rabi frequency, making the quantum dot a sensitive probe of the local magnetic
field and enabling the detection of the state of a nearby spin. If the dot-spin
and the nearby spin have different g-factors a non-demolition readout of the
spin state can be achieved. The conditions for a reliable spin readout are
found.",0812.0459v1
2009-05-10,Quantum size effects on spin-tunneling time in a magnetic resonant tunneling diode,"We study theoretically the quantum size effects of a magnetic resonant
tunneling diode (RTD) with a (Zn,Mn)Se dilute magnetic semiconductor layer on
the spin-tunneling time and the spin polarization of the electrons. The results
show that the spin-tunneling times may oscillate and a great difference between
the tunneling time of the electrons with opposite spin directions can be
obtained depending on the system parameters. We also study the effect of
structural asymmetry which is related to the difference in the thickness of the
nonmagnetic layers. It is found that the structural asymmetry can greatly
affect the traversal time and the spin polarization of the electrons tunneling
through the magnetic RTD. The results indicate that, by choosing suitable
values for the thickness of the layers, one can design a high speed and perfect
spin-filter diode.",0905.1496v2
2009-06-29,Pumping of nuclear spins by the optical solid effect in a quantum dot,"We demonstrate that efficient optical pumping of nuclear spins in
semiconductor quantum dots (QDs) can be achieved by resonant pumping of
optically ""forbidden"" transitions. This process corresponds to one-to-one
conversion of a photon absorbed by the dot into a polarized nuclear spin, which
also has potential for initialization of hole spin in QDs. Pumping via the
""forbidden"" transition is a manifestation of the ""optical solid effect"", an
optical analogue of the effect previously observed in electron spin resonance
experiments in the solid state. We find that by employing this effect, nuclear
polarization of 65% can be achieved, the highest reported so far in optical
orientation studies in QDs. The efficiency of the spin pumping exceeds that
employing the allowed transition, which saturates due to the low probability of
electron-nuclear spin flip-flop.",0906.5260v2
2009-08-03,Direct Measurement of Quantum Dot Spin Dynamics using Time-Resolved Resonance Fluorescence,"We temporally resolve the resonance fluorescence from an electron spin
confined to a single self-assembled quantum dot to measure directly the spin's
optical initialization and natural relaxation timescales. Our measurements
demonstrate that spin initialization occurs on the order of microseconds in the
Faraday configuration when a laser resonantly drives the quantum dot
transition. We show that the mechanism mediating the optically induced
spin-flip changes from electron-nuclei interaction to hole-mixing interaction
at 0.6 Tesla external magnetic field. Spin relaxation measurements result in
times on the order of milliseconds and suggest that a $B^{-5}$ magnetic field
dependence, due to spin-orbit coupling, is sustained all the way down to 2.2
Tesla.",0908.0292v1
2009-08-25,Spin-Dependent Recombination between Phosphorus Donors in Silicon and Si/SiO2 Interface States Investigated with Pulsed Electrically Detected Electron Double Resonance,"We investigate the spin species relevant for the spin-dependent recombination
used for the electrical readout of coherent spin manipulation in
phosphorus-doped silicon. Via a multi-frequency pump-probe experiment in pulsed
electrically detected magnetic resonance, we demonstrate that the dominant
spin-dependent recombination transition occurs between phosphorus donors and
Si/SiO2 interface states. Combining pulses at different microwave frequencies
allows us to selectively address the two spin subsystems participating in the
recombination process and to coherently manipulate and detect the relative spin
orientation of the two recombination partners.",0908.3612v2
2009-12-06,Resonant all-electric spin pumping with spin-orbit coupling,"All-electric devices for the generation and filtering of spin currents are of
crucial importance for spintronics experiments and applications. Here we
consider a quantum dot between two metallic leads in the presence of spin-orbit
coupling, and we analyze in the frame of a scattering matrix approach the
conditions for generating spin currents in an adiabatically driven two-terminal
device. We then focus on a dot with two resonant orbitals and show by specific
examples that both spin filtering and pure spin current generation can be
achieved. Finally, we discuss the effect of the Coulomb interaction.",0912.1096v2
2010-03-29,Sub-optical resolution of single spins using magnetic resonance imaging at room temperature in diamond,"There has been much recent interest in extending the technique of magnetic
resonance imaging (MRI) down to the level of single spins with sub-optical
wavelength resolution. However, the signal to noise ratio for images of
individual spins is usually low and this necessitates long acquisition times
and low temperatures to achieve high resolution. An exception to this is the
nitrogen-vacancy (NV) color center in diamond whose spin state can be detected
optically at room temperature. Here we apply MRI to magnetically equivalent NV
spins in order to resolve them with resolution well below the optical
wavelength of the readout light. In addition, using a microwave version of MRI
we achieved a resolution that is 1/270 size of the coplanar striplines, which
define the effective wavelength of the microwaves that were used to excite the
transition. This technique can eventually be extended to imaging of large
numbers of NVs in a confocal spot and possibly to image nearby dark spins via
their mutual magnetic interaction with the NV spin.",1003.5533v1
2010-09-28,Coherent optical writing and reading of the exciton spin state in single quantum dots,"We demonstrate a one to one correspondence between the polarization state of
a light pulse tuned to neutral exciton resonances of single semiconductor
quantum dots and the spin state of the exciton that it photogenerates. This is
accomplished using two variably polarized and independently tuned picosecond
laser pulses. The first ""writes"" the spin state of the resonantly excited
exciton. The second is tuned to biexcitonic resonances, and its absorption is
used to ""read"" the exciton spin state. The absorption of the second pulse
depends on its polarization relative to the exciton spin direction. Changes in
the exciton spin result in corresponding changes in the intensity of the
photoluminescence from the biexciton lines which we monitor, obtaining thus a
one to one mapping between any point on the Poincare sphere of the light
polarization to a point on the Bloch sphere of the exciton spin.",1009.5463v2
2011-08-09,AC Susceptibility and Electron Spin Resonance Studies of Spin Dynamics in n Ba$_3$NbFe$_3$Si$_2$O$_{14}$: A Geometrically Frustrated Lattice,"We report ac susceptibility and high-frequency electron spin resonance (ESR)
measurements on the geometrically frustrated compound
Ba$_3$NbFe$_3$Si$_2$O$_{14}$ with the N\'{e}el temperature $T_N=27 K$. An
unusually large frequency-dependence of ac susceptibility in the temperature
range of 20 - 100 K reveals a spin-glass-like behavior, signalling the presence
of frustration related slow magnetic fluctuations. ESR experiments show a
multi-step magnetic and spin chirality ordering process. For temperatures above
30 K, the weak temperature dependence of the ESR linewidth $\Delta
H_{pp}\propto T^{-p}$ with $p=0.8$ evidences the development of short-range
correlated spin clusters. The critical broadening with $p =1.8$, persisting
down to 14 K, indicates the coexistence of the short-range ordered spin
clusters within a helically ordered state. Below 9.5 K, the anomalously large
decrease of the linewidth reveals the stabilization of a long-range ordered
state with one chirality.",1108.1853v1
2011-11-23,Anisotropic spin relaxation revealed by resonant spin amplification in (110) GaAs quantum wells,"We have studied spin dephasing in a high-mobility two-dimensional electron
system (2DES), confined in a GaAs/AlGaAs quantum well grown in the [110]
direction, using the resonant spin amplification (RSA) technique. From the
characteristic shape of the RSA spectra, we are able to extract the spin
dephasing times (SDT) for electron spins aligned along the growth direction or
within the sample plane, as well as the $g$ factor. We observe a strong
anisotropy in the spin dephasing times. While the in-plane SDT remains almost
constant as the temperature is varied between 4 K and 50 K, the out-of-plane
SDT shows a dramatic increase at a temperature of about 25 K and reaches values
of about 100 ns. The SDTs at 4 K can be further increased by additional, weak
above-barrier illumination. The origin of this unexpected behavior is
discussed, the SDT enhancement is attributed to the redistribution of charge
carriers between the electron gas and remote donors.",1111.5438v2
2011-12-15,Spin transition in LaCoO3 investigated by resonant soft X-ray emission spectroscopy,"The spin transition in LaCoO3 is investigated by temperature-dependent
resonant soft X-ray emission spectroscopy near the Co 2p absorption edges. This
element-specific technique is more bulk sensitive with respect to the
temperature induced spin-state of the Co3+ ions in LaCoO3 than other
high-energy spectroscopic methods. The spin transition is interpreted and
discussed with ab-initio density-functional theory within the fixed-spin moment
method, which is found to yield consistent spectral functions to the
experimental data. The spectral changes for LaCoO3 as a function of temperature
suggest a change in spin-state as the temperature is raised from 85 to 300 K
while the system remains in the same spin state as the temperature is further
increased to 510 K.",1112.3406v2
2012-03-15,Resonance Measurement of Nonlocal Spin Torque in a Three-Terminal Magnetic Device,"A pure spin current generated within a nonlocal spin valve can exert a spin
transfer torque on a nanomagnet. This nonlocal torque enables new design
schemes for magnetic memory devices that do not require the application of
large voltages across tunnel barriers that can suffer electrical breakdown.
Here we report a quantitative measurement of this nonlocal spin torque using
spin-torque-driven ferromagnetic resonance. Our measurement agrees well with
the prediction of an effective circuit model for spin transport. Based on this
model, we suggest strategies for optimizing the strength of nonlocal torque.",1203.3266v2
2012-03-23,Spin dynamics in a strongly driven system: very slow Rabi oscillations,"We consider joint effects of tunneling and spin-orbit coupling on driven by
electric field spin dynamics in a double quantum dot with a multi-level
resonance scenario. We demonstrate that tunneling plays the crucial role in the
formation of the Rabi-like spin-flip transitions. In contrast to the linear
behavior for weak electric fields, the spin flip rate becomes much smaller than
expected for the two-level model and shows oscillating dependence on the
driving field amplitude in stronger fields. In addition, the full spin flip is
very difficult to achieve in a multi-level resonant system. These two effects
have a similarity with the Zeno effect of slowing down the dynamics of an
observable by its measurement. As a result, spin manipulation by electric field
becomes much less efficient than expected.",1203.5287v1
2012-07-12,Spin Damping in an RF Atomic Magnetometer,"Under negative feedback, the quality factor Q of a radio-frequency
magnetometer can be decreased by more than two orders of magnitude, so that any
initial perturbation of the polarized spin system can be rapidly damped,
preparing the magnetometer for detection of the desired signal. We find that
noise is also suppressed under such spin-damping, with a characteristic
spectral response corresponding to the type of noise; therefore magnetic,
photon-shot, and spin-projection noise can be measured distinctly. While the
suppression of resonant photon-shot noise implies the closed-loop production of
polarization-squeezed light, the suppression of resonant spin-projection noise
does not imply spin-squeezing, rather simply the broadening of the noise
spectrum with Q. Furthermore, the application of spin-damping during
phase-sensitive detection suppresses both signal and noise in such a way as to
increase the sensitivity bandwidth. We demonstrate a three-fold increase in the
magnetometer's bandwidth while maintaining 0.3 fT/\surdHz sensitivity.",1207.2842v1
2013-01-21,Spin-orbit-induced bound state and molecular signature of the degenerate Fermi gas in a narrow Feshbach resonance,"In this paper we explore the spin-orbit-induced bound state and molecular
signature of the degenerate Fermi gas in a narrow Feshbach resonance based on a
generalized two-channel model. Without the atom-atom interactions, only one
bound state can be found even if spin-orbit coupling exists. Moreover, the
corresponding bound-state energy depends strongly on the strength of spin-orbit
coupling, but is influenced slightly by its type. In addition, we find that
when increasing the strength of spin-orbit coupling, the critical point at
which the molecular fraction vanishes shifts from zero to the negative
detuning. In the weak spin-orbit coupling, this shifting is proportional to the
square of its strength. Finally, we also show that the molecular fraction can
be well controlled by spin-orbit coupling.",1301.4718v2
2013-05-05,Cavity cooling of an ensemble spin system,"We describe how sideband cooling techniques may be applied to large spin
ensembles in magnetic resonance. Using the Tavis-Cummings model in the presence
of a Rabi drive, we solve a Markovian master equation describing the joint
spin-cavity dynamics to derive cooling rates as a function of ensemble size.
Our calculations indicate that the coupled angular momentum subspaces of a spin
ensemble containing roughly $10^{11}$ electron spins may be polarized in a time
many orders of magnitude shorter than the typical thermal relaxation time. The
described techniques should permit efficient removal of entropy for spin-based
quantum information processors and fast polarization of spin samples. The
proposed application of a standard technique in quantum optics to magnetic
resonance also serves to reinforce the connection between the two fields, which
has recently begun to be explored in further detail due to the development of
hybrid designs for manufacturing noise-resilient quantum devices.",1305.1029v2
2013-08-15,Detection of the microwave spin pumping using the inverse spin Hall effect,"We report electrical detection of the dynamical part of the spin pumping
current emitted during ferromagnetic resonance (FMR) using the inverse Spin
Hall Effect (ISHE). The experiment is performed on a YIG$|$Pt bilayer. The
choice of YIG, a magnetic insulator, ensures that no charge current flows
between the two layers and only pure spin current produced by the magnetization
dynamics are transferred into the adjacent strong spin-orbit Pt layer via spin
pumping. To avoid measuring the parasitic eddy currents induced at the
frequency of the microwave source, a resonance at half the frequency is induced
using parametric excitation in the parallel geometry. Triggering this nonlinear
effect allows to directly detect on a spectrum analyzer the microwave component
of the ISHE voltage. Signals as large as 30 $\mu$V are measured for precession
angles of a couple of degrees. This direct detection provides a novel efficient
means to study magnetization dynamics on a very wide frequency range with great
sensitivity.",1308.3433v2
2013-09-22,Low temperature MQ NMR dynamics in dipolar ordered state,"We investigate analytically and numerically the Multiple Quantum (MQ) NMR
dynamics in dipolar ordered spin systems of nuclear spins 1/2 at a low
temperatures. We suggest two different methods of MQ NMR. One of them is based
on the measurement of the dipolar energy. The other method uses an additional
resonance ({\pi}/4)_{y}-pulse after the preparation period of the standard MQ
NMR experiment in solids and allows one to measure the Zeeman energy. The both
considered methods are sensitive to the contribution of remote spins in the
interaction and to the spin system structure. The QS method is sensitive to the
spin number in the molecule while the PS method gives very similar time
dependencies of the intensities of MQ coherences for different spin numbers. It
is shown that the use of the dipolar ordered initial state has the advantage of
exciting the highest order MQ coherences in clusters of 4m identical spins,
where m=1,2,3..., that is impossible to do with the standard MQ method. MQ NMR
methods based on the dipolar ordered initial states at low temperatures
complement the standard NMR spectroscopy for better studying structures and
dynamic processes in solids.",1309.5591v1
2013-11-06,Magnetization dynamics of cobalt grown on graphene,"Ferromagnetic resonance (FMR) spin pumping is a rapidly growing field which
has demonstrated promising results in a variety of material systems. This
technique utilizes the resonant precession of magnetization in a ferromagnet to
inject spin into an adjacent non-magnetic material. Spin pumping into graphene
is attractive on account of its exceptional spin transport properties. This
article reports on FMR characterization of cobalt grown on CVD graphene and
examines the validity of linewidth broadening as an indicator of spin pumping.
In comparison to cobalt samples without graphene, direct contact
cobalt-on-graphene exhibits increased FMR linewidth--an often used signature of
spin pumping. Similar results are obtained in Co/MgO/graphene structures, where
a 1nm MgO layer acts as a tunnel barrier. However, SQUID, MFM, and Kerr
microscopy measurements demonstrate increased magnetic disorder in cobalt grown
on graphene, perhaps due to changes in the growth process and an increase in
defects. This magnetic disorder may account for the observed linewidth
enhancement due to effects such as two-magnon scattering or mosaicity. As such,
it is not possible to conclude successful spin injection into graphene from FMR
linewidth measurements alone.",1311.1441v1
2013-12-18,Spin-Orbit Qubit on a Multiferroic Insulator in a Superconducting Resonator,"We propose a spin-orbit qubit in a nanowire quantum dot on the surface of a
multiferroic insulator with a cycloidal spiral magnetic order. The spiral
exchange field from the multiferroic insulator causes an inhomogeneous
Zeeman-like interaction on the electron spin in the quantum dot, producing a
spin-orbit qubit. The absence of an external magnetic field benefits the
integration of such spin-orbit qubit into high-quality superconducting
resonators. By exploiting the Rashba spin-orbit coupling in the quantum dot via
a gate voltage, one can obtain an effective spin-photon coupling with an
efficient on/off switching. This makes the proposed device controllable and
promising for hybrid quantum communications.",1312.5159v2
2014-03-13,Fast Room-Temperature Phase Gate on a Single Nuclear Spin in Diamond,"Nuclear spins support long lived quantum coherence due to weak coupling to
the environment, but are difficult to rapidly control using nuclear magnetic
resonance (NMR) as a result of the small nuclear magnetic moment. We
demonstrate a fast ~ 500 ns nuclear spin phase gate on a 14N nuclear spin qubit
intrinsic to a nitrogen-vacancy (NV) center in diamond. The phase gate is
enabled by the hyperfine interaction and off-resonance driving of electron spin
transitions. Repeated applications of the phase gate bang-bang decouple the
nuclear spin from the environment, locking the spin state for up to ~ 140
microseconds.",1403.3311v2
2014-03-13,Resolved sidebands in a strain-coupled hybrid spin-oscillator system,"We report on single electronic spins coupled to the motion of mechanical
resonators by a novel mechanism based on crystal strain. Our device consists of
single-crystalline diamond cantilevers with embedded Nitrogen-Vacancy center
spins. Using optically detected electron spin resonance, we determine the
unknown spin-strain coupling constants and demonstrate that our system resides
well within the resolved sideband regime. We realize coupling strengths
exceeding ten MHz under mechanical driving and show that our system has the
potential to reach strong coupling. Our novel hybrid system forms a resource
for future experiments on spin-based cantilever cooling and coherent
spin-oscillator coupling.",1403.3405v1
2014-03-27,Tight-binding simulations of electrically driven spin-valley transitions in carbon nanotube quantum dots,"We describe dynamics of spin and valley transitions driven by alternating
electric fields in quantum dots defined electrostatically within semiconducting
carbon nanotubes (CNT). We use the tight-binding approach to describe the
states localized within a quantum dot taking into account the circumferential
spin-orbit interaction due to the s-p hybridization and external fields. The
basis of eigenstates localized in the quantum dot is used in the solution of
the time-dependent Schroedinger equation for description of spin flips and
inter-valley transitions that are driven by periodic perturbation in the
presence of coupling between the spin, valley and orbital degrees of freedom.
Besides the first order transitions we find also fractional resonances. We
discuss the transition rates with selection rules that are lifted by atomic
disorder and the bend of the tube. We demonstrate that the electric field
component perpendicular to the axis of the CNT activates spin transitions which
are otherwise absent and that the resonant spin-flip time scales with the
inverse of the electric field.",1403.6970v3
2014-09-30,Current-induced spin torque resonance of magnetic insulators affected by field-like spin-orbit torques and out-of-plane magnetizations,"The spin-torque ferromagnetic resonance (ST-FMR) in a bilayer system
consisting of a magnetic insulator such as Y3Fe5O12 and a normal metal with
spin-orbit interaction such as Pt is addressed theoretically. We model the
ST-FMR for all magnetization directions and in the presence of field-like
spin-orbit torques based on the drift-diffusion spin model and quantum
mechanical boundary conditions. ST-FMR experiments may expose crucial
information about the spin-orbit coupling between currents and magnetization in
the bilayers.",1409.8406v2
2015-02-12,Anti-damping spin transfer torque through epitaxial Nickel oxide,"We prepare the high quality epitaxial
MgO(001)[100]/Pt(001)[100]/NiO(001)[100]/FeNi/SiO2 films to investigate the
spin transport in the NiO antiferromagnetic insulator. The ferromagnetic
resonance measurements of the FeNi under a spin current injection from the Pt
by the spin Hall effect revealed the change of the ferromagnetic resonance
linewidth depending on the amount of the spin current injection. The results
can be interpreted that there is an angular momentum transfer through the NiO.
A high efficient angular momentum transfer we observed in the epitaxial NiO can
be attributed to the well-defined orientation of the antiferromagnetic moments
and the spin quantization axis of the injected spin current.",1502.03855v1
2015-08-12,Spin orbit splitting of the photon induced Fano Resonance in an oscillating graphene electrostatic barrier,"We investigate theoretically the effect of a time dependent oscillating
potential on the transport property of the Dirac Fermion through a monolayer
graphene electrostatic barrier under the influence of the Rashba spin orbit
interaction. The time dependent problem is solved in the frame work of the non
perturbative Floquet approach. It is noted that the dynamic condition of the
barrier may be controlled by tuning the Rashba parameter. Introduction of the
spin orbit interaction causes splitting of the Fano resonance(FR), a
characteristic feature in photon assisted tunneling. The separation between the
spin split FR gives an indirect measure of the fine structure of the quasihole
bound state inside the barrier. The present findings on the Rashba splitting of
the FR and its external control by tuning the oscillating field parameters
might have potential for applications in spintronic devices, especially in the
spin field effect transistors. The spin polarization of different Floquet
sidebands is found to be quite sensitive to the spin pseudospin interaction.",1508.02888v1
2016-04-24,Who pumps spin current into nonmagnetic-metal (NM) layer in YIG/NM multilayers at ferromagnetic resonance?,"Spin pumping in Yttrium-iron-garnet (YIG)/nonmagnetic-metal (NM) layer
systems under ferromagnetic resonance (FMR) conditions is a popular method of
generating spin current in the NM layer. A good understanding of the spin
current source is essential in extracting spin Hall angle of the NM and in
potential spintronics applications. It is widely believed that spin current is
pumped from precessing YIG magnetization into NM layer. Here, by combining
microwave absorption and DC-voltage measurements on YIG/Pt and YIG/NM1/NM2
(NM1=Cu or Al, NM2=Pt or Ta), we unambiguously showed that spin current in NM
came from the magnetized NM surface (in contact with YIG) due to the magnetic
proximity effect (MPE), rather than the precessing YIG magnetization. This
conclusion is reached through our unique detecting method where the FMR
microwave absorption of the magnetized NM surface, hardly observed in the
conventional FMR experiments, was greatly amplified when the electrical
detection circuit was switched on.",1604.07025v1
2017-08-06,Asymmetric Andreev resonant state with a magnetic exchange field in spin-triplet superconducting monolayer $MoS_2$,"Featuring spin-valley degree of freedom by a magnetic exchange
field-induction to gain transport of charge carriers through a junction based
on superconducting subgap tunneling can provide a new scenario for future
electronics. Transmission of low-energy Dirac-like electron (hole)
quasiparticles through a ferromagnet/superconductor (F/S) interface can be of
noticeable importance due to strong spin-orbit coupling in the valence band of
monolayer $MoS_2$ (ML-MDS). The magnetic exchange field (MEF) of a
ferromagnetic section on top of ML-MDS may affect the electron (hole)
excitations for spin-up and spin-down electrons, differently. Tuning the MEF
enables one to control either electrical properties (such as band gap, SOC and
etc.) or spin-polarized transport. We study the influence of MEF on the
chirality of Andreev resonant state (ARS) appearing at the relating F/S
interface, in which the induced pairing order parameter is chiral $p$-wave
symmetry. The resulting normal conductance is found to be more sensitive to the
magnitude of MEF and doping regime of F region. Unconventional spin-triplet
$p$-wave symmetry features the zero-bias conductance, which strongly depends on
$p$-doping level of F region in the relating NFS junction.",1708.01863v1
2017-09-07,Tunable spin pumping in exchange coupled magnetic trilayers,"Magnetic thin films at ferromagnetic resonance (FMR) leak angular momentum,
which may be absorbed by adjacent layers. This phenomenon, known as spin
pumping, is manifested by an increase in the resonance linewidth ($\Delta H$),
and the closely related Gilbert damping. Another effect of this transfer of
spin currents is a dynamical and long-range coupling that can drive two
magnetic layers into a collective precession when their FMR frequencies
coincide. A collective behavior is also found in magnetic trilayers with
interlayer exchange coupling (IEC). In this study we investigate the interplay
between IEC and spin pumping, using Co/Cu/Py pseudo-spin values. We employ
broadband FMR spectroscopy to explore both the frequency and coupling-strength
dependence of $\Delta H$. Our observations show that there exists a cut-off
frequency, set by the IEC strength, below which the precession is truly
collective and the spin pumping is suppressed. These results demonstrate that
it is possible to control the spin pumping efficiency by varying the frequency
or the interlayer exchange coupling.",1709.02295v1
2019-11-03,Magnetic damping modulation in $IrMn_{3}/Ni_{80}Fe_{20}$ via the magnetic spin Hall effect,"Non-collinear antiferromagnets can have additional spin Hall effects due to
the net chirality of their magnetic spin structure, which provides for more
complex spin-transport phenomena compared to ordinary non-magnetic materials.
Here we investigated how ferromagnetic resonance of permalloy
($Ni_{80}Fe_{20}$) is modulated by spin Hall effects in adjacent epitaxial
$IrMn_{3}$ films. We observe a large dc modulation of the ferromagnetic
resonance linewidth for currents applied along the [001] $IrMn_{3}$ direction.
This very strong angular dependence of spin-orbit torques from dc currents
through the bilayers can be explained by the magnetic spin Hall effect where
$IrMn_{3}$ provides novel pathways for modulating magnetization dynamics
electrically.",1911.00943v1
2017-05-16,Theory of electron spin resonance in one-dimensional topological insulators with spin-orbit couplings,"Edge/surface states often appear in a topologically nontrivial phase, when
the system has a boundary. The edge state of a one-dimensional topological
insulator is one of the simplest examples. Electron Spin Resonance (ESR) is an
ideal probe to detect and analyze the edge state for its high sensitivity and
precision. We consider ESR of the edge state of a generalized
Su-Schrieffer-Heeger model with a next-nearest neighbor (NNN) hopping and a
staggered spin-orbit coupling. The spin-orbit coupling is generally expected to
bring about nontrivial changes on the ESR spectrum. Nevertheless, in the
absence of the NNN hoppings, we find that the ESR spectrum is unaffected by the
spin-orbit coupling thanks to the chiral symmetry. In the presence of both the
NNN hopping and the spin-orbit coupling, on the other hand, the edge ESR
spectrum exhibits a nontrivial frequency shift. We derive an explicit
analytical formula for the ESR shift in the second order perturbation theory,
which agrees very well with a non-perturbative numerical calculation.",1705.05826v3
2017-05-17,Quantum criticality in the coupled two-leg spin ladder Ba2CuTeO6,"We report on zero-field muon spin rotation, electron spin resonance and
polarized Raman scattering measurements of the coupled quantum spin ladder
Ba2CuTeO6. Zero-field muon spin rotation and electron spin resonance probes
disclose a successive crossover from a paramagnetic through a spin-liquid-like
into a magnetically ordered state with decreasing temperature. More
significantly, the two-magnon Raman response obeys a T-linear scaling relation
in its peak energy, linewidth and intensity. This critical scaling behavior
presents an experimental signature of proximity to a quantum critical point
from an ordered side in Ba2CuTeO6.",1705.06035v1
2018-07-13,Dynamical decoupling of interacting dipolar spin ensembles,"We demonstrate that CPMG and XYXY decoupling sequences with non-ideal $\pi$
pulses can reduce dipolar interactions between spins of the same species in
solids. Our simulations of pulsed electron spin resonance (ESR) experiments
show that $\pi$ rotations with small ($<$~10\%) imperfections refocus
instantaneous diffusion. Here, the intractable N-body problem of interacting
dipoles is approximated by the average evolution of a single spin in a changing
mean field. These calculations agree well with experiments and do not require
powerful hardware. Our results add to past attempts to explain similar
phenomena in solid state nuclear magnetic resonance (NMR). Although the
fundamental physics of NMR are similar to ESR, the larger linewidths in ESR and
stronger dipolar interactions between electron spins compared to nuclear spins
preclude drawing conclusions from NMR studies alone. For bulk spins, we also
find that using XYXY results in less inflation of the deduced echo decay times
as compared to decays obtained with CPMG.",1807.04908v1
2012-09-03,Dynamical Jahn-Teller Effect in Spin-Orbital Coupled System,"Dynamical Jahn-Teller (DJT) effect in a spin-orbital coupled system on a
honeycomb lattice is examined, motivated from recently observed spin-liquid
behavior in Ba$_3$CuSb$_2$O$_9$. An effective vibronic Hamiltonian, where the
superexchange interaction and the DJT effect are taken into account, is
derived. We find that the DJT effect induces a spin-orbital resonant state
where local spin-singlet states and parallel orbital configurations are
entangled with each other. This spin-orbital resonant state is realized in
between an orbital ordered state, where spin-singlet pairs are localized, and
an antiferromagnetic ordered state. Based on the theoretical results, a
possible scenario for Ba$_3$CuSb$_2$O$_9$ is proposed.",1209.0239v2
2020-03-04,Programmable two-qubit gates in capacitively coupled flopping-mode spin qubits,"Recent achievements in the field of gate defined semiconductor quantum dots
reinforce the concept of a spin-based quantum computer consisting of nodes of
locally connected qubits which communicate with each other via superconducting
circuit resonator photons. In this work we theoretically demonstrate a
versatile set of quantum gates between adjacent spin qubits defined in
semiconductor quantum dots situated within the same node of such a spin-based
quantum computer. The electric dipole acquired by the spin of an electron that
moves across a double quantum dot potential in a magnetic field gradient has
enabled strong coupling to resonator photons and low-power spin control. Here
we show that this flopping-mode spin qubit also provides with the tunability to
program multiple two-qubit gates. Since the capacitive coupling between these
qubits brings about additional dephasing, we calculate the estimated infidelity
of different two-qubit gates in the most immediate possible experimental
realizations.",2003.02137v3
2020-03-10,Dynamics of a two-dimensional quantum spin-orbital liquid: spectroscopic signatures of fermionic magnons,"We provide an exact study of dynamical correlations for the quantum
spin-orbital liquid phases of an SU(2)-symmetric Kitaev honeycomb lattice
model. We show that the spin dynamics in this Kugel-Khomskii type model is
exactly the density-density correlation function of S=1 fermionic magnons,
which could be probed in resonant inelastic x-ray scattering experiments. We
predict the characteristic signatures of spin-orbital fractionalization in
inelastic scattering experiments and compare them to the ones of the
spin-anisotropic Kitaev honeycomb spin liquid. In particular, the resonant
inelastic x-ray scattering response shows a characteristic momentum dependence
directly related to the dispersion of fermionic excitations. The neutron
scattering cross section displays a mixed response of fermionic magnons as well
as spin-orbital excitations. The latter has a bandwidth of broad excitations
and a vison gap that is three times larger than that of the spin-1/2 Kitaev
model.",2003.04835v3
2021-08-03,Unusual spin pseudogap behavior in the spin web lattice Cu$_3$TeO$_6$ probed by $^{125}$Te nuclear magnetic resonance,"We present a $^{125}$Te nuclear magnetic resonance (NMR) study in the
three-dimensional spin web lattice Cu$_3$TeO$_6$, which harbors topological
magnons. The $^{125}$Te NMR spectra and the Knight shift $\mathcal{K}$ as a
function of temperature show a drastic change at $T_\text{S}\sim 40$ K much
lower than the N\'eel ordering temperature $T_\text{N}\sim 61$ K, providing
evidence for the first-order structural phase transition within the
magnetically ordered state. Most remarkably, the temperature dependence of the
spin-lattice relaxation rate $T_1^{-1}$ unravels spin-gap-like magnetic
excitations, which sharply sets in at $T^*\sim 75$ K, the temperature well
above $T_\text{N}$. The spin gap behavior may be understood by weakly
dispersive optical magnon branches of high-energy spin excitations originating
from the unique corner-sharing Cu hexagon spin-1/2 network with low
coordination number.",2108.01288v1
2019-01-03,Detecting Spin Transport in Quantum Magnets with Photons,"A minimally invasive technique is proposed for detecting the differential
spin conductance and spin current noise across a junction between two quantum
magnets using a high-quality microwave resonator coupled to a transmission line
which is impedance matched to a photon detector downstream. Photons in the
microwave resonator couple inductively to the spins in the spin subsystem, and
the noise in the junction spin current imprints itself into the output photons
propagating along the transmission line. The technique is capable of extracting
both the dc and finite frequency noise via the output photon flux and of
measuring the junction spin conductance by driving the electromagnetic
environment into a different temperature regime.",1901.00933v2
2019-07-04,Electron spin resonance study of spin relaxation in the strong-leg spin ladder with nonmagnetic dilution,"We have studied electron spin resonance (ESR) absorption spectra for the
nonmagnetically diluted strong-leg spin ladder magnet
({C}$_{7}$H$_{10}$N)$_{2}$Cu$_{(1-x)}$Zn$_{x}$Br$_{4}$ (abbreviated as DIMPY)
down to 450 mK. Formation of the clusters with non-zero net magnetization is
confirmed; the cluster-cluster interaction is evidenced by the concentration
dependence of ESR absorption. High-temperature spin-relaxation time was found
to increase with non-magnetic dilution. The ESR linewidth analysis proves that
the Dzyaloshinskii-Moriya (DM) interaction remains the dominant spin-relaxation
channel in diluted DIMPY. Experimental data indicate that the dilution results
in the weakening of the effective DM interaction, which can be interpreted as
total suppression of DM interaction in the close vicinity of impurity atom.",1907.02284v2
2020-07-20,Regulating spin dynamics of graphene flakes,"A method of regulating spin dynamics of the so-called magnetic graphene is
analyzed. Magnetic moments can be incorporated into graphene flakes and
graphene ribbons through defects, such as adatoms and vacancies. Local spins
can also be attached to graphene at hydrogenated zigzag edges. Spin flips can
be produced by transverse pulses and by connecting the sample to a resonance
electric coil. The action of the resonator feedback field strongly accelerates
spin reversal. The possibility of fast spin reversal is important for
spintronics and for quantum information processing allowing for an efficient
functioning of spin registers.",2007.10217v1
2020-10-18,Quantifying power flow processes mediated by spin currents,"The power flow process mediated by spin current in the bilayer device
consisting of ferromagnetic metal (FM) and non-magnetic metal (NM) layers is
examined by realizing experimental evaluations for each process from the
microwave absorption to electromotive force (EMF) output. The absorption power
by ferromagnetic resonance (FMR) of the thin FM layer during the EMF output is
directly measured in operando using an antenna probe system. The transfer
efficiency of the absorption power into the NM layer by spin pumping is
estimated from strict linewidth evaluation of EMF spectra. The maximum transfer
efficiency of the spin pumping power to the external load via the inverse spin
Hall effect is determined to be 4.2X10^(-8) under 160mW microwave irradiation
using an analysis model assuming a parallel circuit. The main factors reducing
the efficiency are found to be low resistivity of the NM layer and the
interface loss. These quantifications are important as a first step to consider
the efficient transfer of spin energy mediated by spin currents.",2010.08997v3
2021-12-08,Giant Resonant Self-Blocking in Magnetophononically Driven Quantum Magnets,"Magnetophononics, the modulation of magnetic interactions by driven
infrared-active lattice excitations, is emerging as a key mechanism for the
ultrafast dynamical control of both semiclassical and quantum spin systems by
coherent light. We demonstrate that, in a quantum magnetic material with strong
spin-phonon coupling, resonances between the driven phonon and the spin
excitation frequencies exhibit a giant self-blocking effect. Instead of
absorbing more energy, the spin system acts as a strong brake on the driven
phonon, causing it to absorb only a tiny fraction of the power available from
the laser. Using the quantum master equations governing the nonequilibrium
steady states of the coupled spin-lattice system, we show how self-blocking
dominates the dynamics, demonstrate the creation of mutually repelling hybrid
spin-phonon states, and control the nonequilibrium renormalization of the
lattice-driven spin excitation band.",2112.04508v1
2021-12-23,Quantum parameter estimation of nonlinear coupling in trilinear Hamiltonian with trapped ions,"I propose an efficient method for measuring non-linear coupling between the
collective axial breathing mode and the radial rocking mode induced by the
mutual Coulomb repulsion in linear ion crystal. The quantum sensing technique
is based on the laser induced coupling between one of the vibrational modes and
the internal ion's spin states which allows to estimate the non-linear coupling
either by measuring the phonon probability distribution or directly be
observing the Ramsey-type oscillations of the ion spin states. I show that due
to the presence of non-linear phonon coupling the off-resonance interaction
between the ion spin states and the axial breathing mode leads to
spin-dependent phonon squeezing of the radial rocking mode. Thus the non-linear
coupling can be estimated by measuring population distribution of the motional
squeezed state. Furthermore, I show that the off-resonance interaction between
the spin and the radial rocking mode creates a spin-dependent beam splitter
operation between the two vibrational modes. Thus, the parameter estimation can
be carried out by detecting the ion spin populations. Finally, I show that the
measurement uncertainty precision can reach the Heisenberg limit by using an
entangled states between the two collective modes.",2112.12487v1
2022-04-01,Tunable hole spin-photon interaction based on g-matrix modulation,"We consider a spin circuit-QED device where a superconducting microwave
resonator is capacitively coupled to a single hole confined in a semiconductor
quantum dot. Thanks to the strong spin-orbit coupling intrinsic to valence-band
states, the gyromagnetic g-matrix of the hole can be modulated electrically.
This modulation couples the photons in the resonator to the hole spin. We show
that the applied gate voltages and the magnetic-field orientation enable a
versatile control of the spin-photon interaction, whose character can be
switched from fully transverse to fully longitudinal. The longitudinal coupling
is actually maximal when the transverse one vanishes and vice-versa. This
""reciprocal sweetness"" results from geometrical properties of the g-matrix and
protects the spin against dephasing or relaxation. We estimate coupling rates
reaching ~ 10 MHz in realistic settings and discuss potential circuit-QED
applications harnessing either the transverse or the longitudinal spin-photon
interaction. Furthermore, we demonstrate that the g-matrix curvature can be
used to achieve parametric longitudinal coupling with enhanced coherence.",2204.00404v3
2022-09-22,Electric Control of Spin Transitions at the Atomic Scale,"Electric control of spins has been a longstanding goal in the field of solid
state physics due to the potential for increased efficiency in information
processing. This efficiency can be optimized by transferring spintronics to the
atomic scale. We present electric control of spin resonance transitions in
single molecules by employing electron spin resonance scanning tunneling
microscopy (ESR-STM). We find strong bias voltage dependent shifts in the ESR
signal of about ten times its linewidth, which is due to the electric field
induced displacement of the spin system in the tunnel junction. This opens up
new avenues for ultrafast control of coupled spin systems, even towards atomic
scale quantum computing, and expands on understanding and optimizing spin
electric coupling in bulk materials.",2209.10969v1
2023-01-01,Spin Hall Induced Magnetization Dynamics in Multiferroic Tunnel Junction,"The combination of spin-orbit coupling driven effects and multiferroic
tunneling properties was explored experimentally in thin Pt/Co/BTO/LSMO
multilayers. The presence of a Pt heavy metal allows for the spin
current-induced magnetization precession of Co upon radio-frequency charge
current injection. The utilization of a BTO ferroelectric tunnel barrier
separating the Co and LSMO ferromagnetic electrodes gives rise to both
tunneling-magnetoresistance and electroresistance. Using the spin-orbit torque
ferromagnetic resonance, the maganetization dynamics of the Co/Pt bilayers was
studied at room temperature. Unexpectedly the magnetization dynamics study in
the same geometry performed at low temperature reveals the existence of both Co
and LSMO resonance peaks indicating efficient spin current generation both
using the spin Hall effect in Pt and spin pumping in LSMO that tunnel via the
BTO barrier.",2301.00459v1
2023-03-13,Towards a unified picture of polarization transfer -- pulsed DNP and chemically equivalent PHIP,"Nuclear spin hyperpolarization techniques, such as dynamic nuclear
polarization (DNP) and parahydrogen-induced polarization (PHIP), have
revolutionized nuclear magnetic resonance and magnetic resonance imaging. In
these methods, a readily available source of high spin order, either electron
spins in DNP or singlet states in hydrogen for PHIP, is brought into close
proximity with nuclear spin targets, enabling efficient transfer of spin order
under external quantum control. Despite vast disparities in energy scales and
interaction mechanisms between electron spins in DNP and nuclear singlet states
in PHIP, a pseudo-spin formalism allows us to establish an intriguing
equivalence. As a result, the important low-field polarization transfer regime
of PHIP can be mapped onto an analogous system equivalent to pulsed-DNP. This
establishes a correspondence between key polarization transfer sequences in
PHIP and DNP, facilitating the transfer of sequence development concepts. This
promises fresh insights and significant cross-pollination between DNP and PHIP
polarization sequence developers.",2303.07478v2
2023-06-17,Coherent two-dimensional THz magnetic resonance spectroscopies for molecular magnets: Analysis of Dzyaloshinskii-Moriya interaction,"To investigate the novel quantum dynamic behaviors of magnetic materials that
arise from complex spin-spin interactions, it is necessary to probe the
magnetic response at a speed greater than the spin-relaxation and dephasing
processes. Recently developed two-dimensional (2D) terahertz magnetic resonance
(THz-MR) spectroscopy techniques use the magnetic components of laser pulses,
and this allows investigation of the details of the ultrafast dynamics of spin
systems. For such investigations, quantum treatment -- not only of the spin
system itself but also of the environment surrounding the spin system -- is
important. In our method, based on the theory of multidimensional optical
spectroscopy, we formulate nonlinear THz-MR spectra using an approach based on
the numerically rigorous hierarchical equations of motion. We conduct numerical
calculations of both linear (1D) and 2D THz-MR spectra for a linear chiral spin
chain. The pitch and direction of chirality (clockwise or anticlockwise) are
determined by the strength and sign of the Dzyaloshinskii-Moriya interaction
(DMI). We show that not only the strength but also the sign of the DMI can be
evaluated through the use of 2D THz-MR spectroscopic measurements, while 1D
measurements allow us to determine only the strength.",2306.10222v1
2023-07-23,Unconventional spin polarization at Argon ion milled SrTiO3 Interfaces,"Interfacial two-dimensional electron gas (2DEG) formed at the perovskite-type
oxide, such as SrTiO3, has attracted significant attention due to its
properties of ferromagnetism, superconductivity, and its potential application
in oxide-based low-power consumption electronics. Recent studies have
investigated spin-to-charge conversion at the STO interface with different
materials, which could affect the efficiency of this 2DEG interface. In this
report, we presented an Ar^+ ion milling method to create a 2DEG at STO
directly by inducing oxygen vacancies. To quantify the spin-to-charge
conversion of this interface, we measured the angular-dependent spin-torque
ferromagnetic resonance (ST-FMR) spectra, revealing an unconventional spin
polarization at the interface of Argon ion-milled STO and NiFe. Furthermore, a
micromagnetic simulation for angular-dependent spin-torque ferromagnetic
resonance (ST-FMR) has been performed, confirming the large unconventional spin
polarization at the interface.",2307.12390v1
2023-09-05,Electrically Driven Spin Resonance of 4f Electrons in a Single Atom on a Surface,"A pivotal challenge in quantum technologies lies in reconciling long
coherence times with efficient manipulation of the quantum states of a system.
Lanthanide atoms, with their well-localized 4f electrons, emerge as a promising
solution to this dilemma if provided with a rational design for manipulation
and detection. Here we construct tailored spin structures to perform electron
spin resonance on a single lanthanide atom using a scanning tunneling
microscope. A magnetically coupled structure made of an erbium and a titanium
atom enables us to both drive the erbium's 4f electron spins and indirectly
probe them through the titanium's 3d electrons. In this coupled configuration,
the erbium spin states exhibit a five-fold increase in the spin relaxation time
and a two-fold increase in the driving efficiency compared to the 3d electron
counterparts. Our work provides a new approach to accessing highly protected
spin states, enabling their coherent control in an all-electric fashion.",2309.02348v2
2024-02-02,Theory of Electron Spin Resonance Spectroscopy in Scanning Tunneling Microscope,"The integration of scanning tunneling microscopy (STM) and electron spin
resonance (ESR) spectroscopy has emerged as a powerful and innovative tool for
discerning spin excitations and spin-spin interactions within atoms and
molecules adsorbed on surfaces. However, the origin of the STM-ESR signal and
the underlying mechanisms that govern the essential features of the measured
spectra have remained elusive, thereby significantly impeding the future
development of the STM-ESR approach. Here, we construct a model to carry out
precise numerical simulations of STM-ESR spectra for a single hydrogenated Ti
adatom and a hydrogenated Ti dimer, achieving excellent agreement with
experimental observations. We further develop an analytic theory that
elucidates the fundamental origin of the signal as well as the essential
features in the measured spectra. These new theoretical developments establish
a solid foundation for the on-demand detection and manipulation of atomic-scale
spin states, with promising implications for cutting-edge applications in spin
sensing, quantum information, and quantum computing.",2402.01435v2
2014-07-24,Fano collective resonance as complex mode in a two dimensional planar metasurface of plasmonic nanoparticles,"Fano resonances are features in transmissivity/reflectivity/absorption that
owe their origin to the interaction between a bright resonance and a dark
(i.e., sub-radiant) narrower resonance, and may emerge in the optical
properties of planar two-dimensional (2D) periodic arrays (metasurfaces) of
plasmonic nanoparticles. In this Letter, we provide a thorough assessment of
their nature for the general case of normal and oblique plane wave incidence,
highlighting when a Fano resonance is affected by the mutual coupling in an
array and its capability to support free modal solutions. We analyze the
representative case of a metasurface of plasmonic nanoshells at ultraviolet
frequencies and compute its absorption under TE- and TM-polarized, oblique
plane-wave incidence. In particular, we find that plasmonic metasurfaces
display two distinct types of resonances observable as absorption peaks: one is
related to the Mie, dipolar resonance of each nanoparticle; the other is due to
the forced excitation of free modes with small attenuation constant, usually
found at oblique incidence. The latter is thus an array-induced collective Fano
resonance. This realization opens up to manifold flexible designs at optical
frequencies mixing individual and collective resonances. We explain the
physical origin of such Fano resonances using the modal analysis, which allows
to calculate the free modes with complex wavenumber supported by the
metasurface. We define equivalent array dipolar polarizabilities that are
directly related to the absorption physics at oblique incidence and show a
direct dependence between array modal phase and attenuation constant and Fano
resonances. We thus provide a more complete picture of Fano resonances that may
lead to the design of filters, energy-harvesting devices, photodetectors, and
sensors at ultraviolet frequencies.",1407.6656v2
2016-12-09,A General Theory for Bandgap Estimation in Locally Resonant Metastructures,"Locally resonant metamaterials are characterized by bandgaps at wavelengths
that are much larger than the lattice size, enabling low-frequency vibration
attenuation. Typically, bandgap analyses and predictions rely on the assumption
of traveling waves in an infinite medium, and do not take advantage of modal
representations typically used for the analysis of the dynamic behavior of
finite structures. Recently, we developed a method for understanding the
locally resonant bandgap in uniform finite metamaterial beams using modal
analysis. Here we extend that framework to general locally resonant
metastructures with specified boundary conditions using a general operator
formulation. Using this approach, along with the assumption of an infinite
number of resonators tuned to the same frequency, the frequency range of the
locally resonant bandgap is easily derived in closed form. Furthermore, the
bandgap expression is shown to be the same regardless of the type of vibration
problem under consideration, depending only on the added mass ratio and target
frequency. It is shown that the number of resonators required for the bandgap
to appear increases with the target frequency range, i.e. respective modal
neighborhood. Furthermore, it is observed that there is an optimal, finite
number of resonators which gives a bandgap that is wider than the
infinite-absorber bandgap, and that the optimal number of resonators increases
with target frequency and added mass ratio. As the number of resonators becomes
sufficiently large, the bandgap converges to the derived infinite-absorber
bandgap. The derived bandgap edge frequencies are shown to agree with results
from dispersion analysis using the plane wave expansion method. Numerical and
experimental investigations are performed regarding the effects of mass ratio,
non-uniform spacing of resonators, and parameter variations among the
resonators.",1612.03130v1
2006-04-15,Observation of high-order quantum resonances in the kicked rotor,"Quantum resonances in the kicked rotor are characterized by a dramatically
increased energy absorption rate, in stark contrast to the momentum
localization generally observed. These resonances occur when the scaled
Planck's constant hbar=(r/s)*4pi, for any integers r and s. However only the
hbar=r*2pi resonances are easily observable. We have observed high-order
quantum resonances (s>2) utilizing a sample of low temperature, non-condensed
atoms and a pulsed optical standing wave. Resonances are observed for
hbar=(r/16)*4pi r=2-6. Quantum numerical simulations suggest that our
observation of high-order resonances indicates a larger coherence length than
expected from an initially thermal atomic sample.",0604110v1
2007-08-22,Shape resonances in modified effective range theory for electron-molecule collisions,"We develop a simple model of shape resonances in electron-molecule collisions
that is based on the modified effective-range expansion and analytical
solutions of the Schrodinger equation for the long-range part of the
interaction potential. We apply our model to electron scattering on N$_2$ and
CO$_2$. The parameters of the effective-range expansion (i.e. the scattering
length and the effective range) are determined from experimental, integral
elastic cross sections in the 0.1 - 1.0 eV energy range. For both molecular
targets our treatment predicts shape resonances that appear slightly higher
than experimentally known resonances in total cross sections. Agreement with
the experiment can be improved by assuming the position of the resonance in a
given partial wave. Influence of quadrupole potential on resonances is also
discussed: it can be disregarded for N$_2$ but gets significant for CO$_2$. In
conclusion, our model developed within the effective range formalism reproduces
well both the very low-energy behavior of the integral cross section as well as
the presence of resonances in the few eV range.",0708.2991v2
2007-10-01,A model for chaotic dielectric microresonators,"We develop a random-matrix model of two-dimensional dielectric resonators
which combines internal wave chaos with the deterministic Fresnel laws for
reflection and refraction at the interfaces. The model is used to investigate
the statistics of the laser threshold and line width (lifetime and Petermann
factor of the resonances) when the resonator is filled with an active medium.
The laser threshold decreases for increasing refractive index $n$ and is
smaller for TM polarization than for TE polarization, but is almost independent
of the number of out-coupling modes $N$. The Petermann factor in the line width
of the longest-living resonance also decreases for increasing $n$ and scales as
$\sqrt{N}$, but is less sensitive to polarization. For resonances of
intermediate lifetime, the Petermann factor scales linearly with $N$. These
qualitative parametric dependencies are consistent with the random-matrix
theory of resonators with small openings. However, for a small refractive index
where the resonators are very open, the details of the statistics become
non-universal. This is demonstrated by comparison with a particular dynamical
model.",0710.0227v1
2009-11-06,Spherical-box approach for resonances in presence of Coulomb interaction,"The spherical-box approach is extended to calculate the resonance parameters
and the real part of the wave function for single particle resonances in a
potential containing the long-range Coulomb interaction. A model potential is
taken to demonstrate the ability and accuracy of this approach. The calculated
resonance parameters are compared with available results from other methods. It
is shown that in the presence of the Coulomb interaction, the spherical-box
approach works well for not so broad resonances. In particular, for very narrow
resonances, the present method gives resonance parameters in a very high
precision.",0911.1171v1
2010-05-16,Resonance spectrum for one-dimensional layered media,"We consider the ""weighted"" operator $P_k=-\partial_x a(x)\partial_x$ on the
line with a step-like coefficient which appears when propagation of waves
thorough a finite slab of a periodic medium is studied. The medium is
transparent at certain resonant frequencies which are related to the complex
resonance spectrum of $P_k.$ If the coefficient is periodic on a finite
interval (locally periodic) with $k$ identical cells then the resonance
spectrum of $P_k$ has band structure. In the present paper we study a
transition to semi-infinite medium by taking the limit $k\to \infty.$
  The bands of resonances in the complex lower half plane are localized below
the band spectrum of the corresponding periodic problem ($k=\infty$) with $k-1$
or $k$ resonances in each band. We prove that as $k\to \infty$ the resonance
spectrum converges to the real axis.",1005.2743v1
2013-01-15,Resonant Bound-Free Contributions to Thomson Scattering of X-rays by Warm Dense Matter,"Recent calculations [Nilsen et al. arXiv:1212.5972] predict that
contributions to the scattered photon spectrum from 3s and 3p bound states in
chromium (Z=24) at metallic density and T=12 eV resonate below the respective
bound-state thresholds. These resonances are shown to be closely related to
continuum lowering, where 3d bound states in the free atom dissolve into a
resonant l=2 partial wave in the continuum. The resulting d-state resonance
dominates contributions to the bound-free dynamic structure function, leading
to the predicted resonances in the scattered X-ray spectrum. Similar resonant
features are shown to occur in all elements in the periodic table between Ca
and Mn (20 <= Z <= 25).",1301.3440v1
2014-03-13,Fano-Feshbach resonances in two-channel scattering around exceptional points,"It is well known that in open quantum systems resonances can coalesce at an
exceptional point, where both the energies {\em and} the wave functions
coincide. In contrast to the usual behaviour of the scattering amplitude at one
resonance, the coalescence of two resonances invokes a pole of second order in
the Green's function, in addition to the usual first order pole. We show that
the interference due to the two pole terms of different order gives rise to
patterns in the scattering cross section which closely resemble Fano-Feshbach
resonances. We demonstrate this by extending previous work on the analogy of
Fano-Feshbach resonances to classical resonances in a system of two driven
coupled damped harmonic oscillators.",1403.3187v1
2014-10-16,Recent development of complex scaling method for many-body resonances and continua in light nuclei,"The complex scaling method (CSM) is a useful similarity transformation of the
Schr\""odinger equation, in which bound-state spectra are not changed but
continuum spectra are separated into resonant and non-resonant continuum ones.
Because the asymptotic wave functions of the separated resonant states are
regularized by the CSM, many-body resonances can be obtained by solving an
eigenvalue problem with the $L^2$ basis functions. Applying this method to a
system consisting of a core and valence nucleons, we investigate many-body
resonant states in weakly bound nuclei very far from the stability lines.
Non-resonant continuum states are also obtained with the discretized
eigenvalues on the rotated branch cuts. Using these complex eigenvalues and
eigenstates in CSM, we construct the extended completeness relations and
Green's functions to calculate strength functions and breakup cross sections.
Various kinds of theoretical calculations and comparisons with experimental
data are presented.",1410.4356v1
2014-10-21,Observation of orbiting resonances in He(3S1) + NH3 Penning ionization,"Resonances are among the clearest quantum mechanical signatures of scattering
processes. Previously, shape resonances and Feshbach resonances have been
observed in inelastic and reactive collisions involving atoms or diatomic
molecules. Structure in the integral cross section has been observed in a
handful of elastic collisions involving polyatomic molecules. The present paper
presents the observation of shape resonances in the reactive scattering of a
polyatomic molecule, NH3. A merged-beam study of the gas phase He((3)S1) + NH3
Penning ionization reaction dynamics is described in the collision energy range
3.3 $\mu$eV < E$_{coll}$ < 10 meV. In this energy range, the reaction rate is
governed by long-range attraction. Peaks in the integral cross section are
observed at collision energies of 1.8 meV and 7.3 meV and are assigned to $\ell
= 15,16$ and $\ell = 20,21$ partial wave resonances, respectively. The
experimental results are well reproduced by theoretical calculations with the
short-range reaction probability P$_{sr}$ = 0.035. No clear signature of the
orbiting resonances is visible in the branching ratio between NH3(+) and NH2(+)
formation.",1410.5651v2
2015-08-26,Probabilistic interpretation of compositeness relation for resonances,"Bound, antibound and resonance states are associated to poles in the on-shell
partial wave amplitudes. We show here that from the residues of the pole a rank
1 projection operator associated with any of these states can be extracted, in
terms of which a sum rule related to the composition of the state can be
derived. Although typically it involves complex coefficients for the
compositeness and elementariness, except for the bound state case, we
demonstrate that one can formulate a meaningful compositeness relation with
only positive coefficients for resonances whose associated Laurent series in
the variable s converges in a region of the physical axis around Re(s_P), with
s_P the pole position of the resonance. It is also shown that this result can
be considered as an analytical extrapolation in s_P of the clear narrow
resonance case. We exemplify this formalism to study the two-body components of
several resonances of interest.",1508.06400v2
2016-05-29,Enhanced light-vapor interactions and all optical switching in a chip scale micro-ring resonator coupled with atomic vapor,"The coupling of atomic and photonic resonances serves as an important tool
for enhancing light-matter interactions and enables the observation of
multitude of fascinating and fundamental phenomena. Here, by exploiting the
platform of atomic-cladding wave guides, we experimentally demonstrate the
resonant coupling of rubidium vapor and an atomic cladding micro ring
resonator. Specifically, we observed cavity-atom coupling in the form of Fano
resonances having a distinct dependency on the relative frequency detuning
between the photonic and the atomic resonances. Moreover, we were able to
significantly enhance the efficiency of all optical switching in the V-type
pump-probe scheme. The coupled system of micro-ring resonator and atomic vapor
is a promising building block for a variety of light vapor experiments, as it
offers a very small footprint, high degree of integration and extremely strong
confinement of light and vapor. As such it may be used for important
applications, such as all optical switching, dispersion engineering (e.g. slow
and fast light) and metrology, as well as for the observation of important
effects such as strong coupling, Purcell enhancement and bistability.",1605.09008v1
2016-05-30,Sign-Reversal Coupling in Coupled-Resonator Optical Waveguide,"Coupled-resonator optical waveguides (CROWs), which play a significant role
in modern photonics, achieve waveguiding through near-field coupling between
tightly localized resonators. The coupling factor, a critical parameter in CROW
theory, determines the coupling strength between two resonators and the
waveguiding dispersion of a CROW. However, the original CROW theory proposed by
Yariv et al. only demonstrated one value of coupling factor for a multipole
resonance mode. Here, by imaging the tight-binding Bloch waves on a CROW
consisting of designer-surface-plasmon resonators in the microwave regime, we
demonstrate that the coupling factor in the CROW theory can reverse its sign
for a multipole resonance mode. This determines two different waveguiding
dispersion curves in the same frequency range, experimentally confirmed by
matching Bloch wavevectors and frequencies in the CROW. Our study supplements
and extends the original CROW theory, and may find novel use in functional
photonic systems.",1605.09163v1
2016-09-22,Transformation of the frequency-modulated continuous-wave field into a train of short pulses by resonant filters,"The resonant filtering method transforming frequency modulated radiation
field into a train of short pulses is proposed to apply in optical domain.
Effective frequency modulation can be achieved by electro-optic modulator or by
resonant frequency modulation of the filter with a narrow absorption line. Due
to frequency modulation narrow-spectrum CW radiation field is seen by the
resonant filter as a comb of equidistant spectral components separated by the
modulation frequency. Tuning narrow-bandwidth filter in resonance with $n$-th
spectral component of the comb transforms the radiation field into bunches of
pulses with $n$ pulses in each bunch. The transformation is explained by the
interference of the coherently scattered resonant component of the field with
the whole comb. Constructive interference results in formation of pulses, while
destructive interference is seen as dark windows between pulses. It is found
that the optimal thickness of the resonant filter is several orders of
magnitude smaller than the necessary thickness of the dispersive filters used
before in optical domain to produce short pulses from the frequency modulated
field.",1609.06872v1
2017-12-07,Double-negative electromagnetic metamaterials due to chirality,"The aim of this paper is to provide a mathematical theory for understanding
the mechanism behind the double-negative refractive index phenomenon in chiral
materials. The design of double-negative metamaterials generally requires the
use of two different kinds of subwavelength resonators, which may limit the
applicability of double-negative metamaterials. Herein, we rely on media that
consist of only a single type of dielectric resonant element, and show how the
chirality of the background medium induces double-negative refractive index
metamaterial, which refracts waves negatively, hence acting as a superlens.
Using plasmonic dielectric particles, it is proved that both the effective
electric permittivity and the magnetic permeability can be negative near some
resonant frequencies. A justification of the approximation of a plasmonic
particle in a chiral medium by the sum of a resonant electric dipole and a
resonant magnetic dipole, is provided. Moreover, the set of resonant
frequencies is characterized. For an appropriate volume fraction of plasmonic
particles with certain conditions on their configuration, a double-negative
effective medium can be obtained when the frequency is near one of the resonant
frequencies.",1712.02863v1
2018-05-05,Signatures of few-body resonances in finite volume,"We study systems of bosons and fermions in finite periodic boxes and show how
the existence and properties of few-body resonances can be extracted from
studying the volume dependence of the calculated energy spectra. Using a
plane-wave-based discrete variable representation to conveniently implement
periodic boundary conditions, we establish that avoided level crossings occur
in the spectra of up to four particles and can be linked to the existence of
multi-body resonances. To benchmark our method we use two-body calculations,
where resonance properties can be determined with other methods, as well as a
three-boson model interaction known to generate a three-boson resonance state.
Finding good agreement for these cases, we then predict three-body and
four-body resonances for models using a shifted Gaussian potential. Our results
establish few-body finite-volume calculations as a new tool to study few-body
resonances. In particular, the approach can be used to study few-neutron
systems, where such states have been conjectured to exist.",1805.02029v2
2019-11-12,Effect of the resonance spectra in the propagation of two decaying entangled particles,"An exact analytical solution of the decaying wave function of two identical
noninteracting particles, which are entangled by spatial symmetry, is used to
analyze the effect of the resonance spectra in the propagation of the decaying
probability density outside the interaction potential region. We find, using
exactly solvable problems, that a usual approximation that considers the two
resonance levels associated with the initial states, is affected substantially
in the case of sharp high energy resonances by disrupting the pure exponential
decaying regime exhibited by the two resonance level approximation, whereas for
broad high energy resonances, we find that the probability density profile is
well described by the two resonance approximation.",1911.05056v1
2014-06-27,Ultrasensitive THz sensing with high-Q Fano resonances in metasurfaces,"High quality factor resonances are extremely promising for designing
ultra-sensitive refractive index label-free sensors since it allows intense
interaction between electromagnetic waves and the analyte material.
Metamaterial and plasmonic sensing has recently attracted a lot of attention
due to subwavelength confinement of electromagnetic fields in the resonant
structures. However, the excitation of high quality factor resonances in these
systems has been a challenge. We excite an order of magnitude higher quality
factor resonances in planar terahertz metamaterials that we exploit for
ultrasensitive sensing. The low-loss quadrupole and Fano resonances with
extremely narrow linewidths enable us to measure the minute spectral shift
caused due to the smallest change in the refractive index of the surrounding
media. We achieve sensitivity levels of 7.75 x 10^3 nm/ RIU with quadrupole and
5.7 x 10^4 nm/ RIU with the Fano resonances which could be further enhanced by
using thinner substrates. These findings would facilitate the design of
ultrasensitive real time chemical and biomolecular sensors in the fingerprint
region of the terahertz regime.",1406.7194v1
2018-02-11,Floquet spectroscopy of a strongly driven quantum dot charge qubit with a microwave resonator,"We experimentally investigate a strongly driven GaAs double quantum dot
charge qubit weakly coupled to a superconducting microwave resonator. The
Floquet states emerging from strong driving are probed by tracing the qubit -
resonator resonance condition. This way we probe the resonance of a qubit that
is driven in an adiabatic, a non-adiabatic, or an intermediate rate showing
distinct quantum features of multi-photon processes and
Landau-Zener-St\""uckelberg interference pattern. Our resonant detection scheme
enables the investigation of novel features when the drive frequency is
comparable to the resonator frequency. Models based on adiabatic approximation,
rotating wave approximation, and Floquet theory explain our experimental
observations.",1802.03810v1
2018-02-20,Dynamo induced by time-periodic force,"To understand the dynamo driven by time-dependent flow, e.g. turbulence, we
investigate numerically the dynamo induced by time-periodic force in rotating
magnetohydrodynamic flow and focus on the effect of force frequency on the
dynamo action. It is found that the dynamo action depends on the force
frequency. When the force frequency is near resonance the force can drive
dynamo but when it is far away from resonance dynamo fails. In the frequency
range near resonance to support dynamo, the force frequency at resonance
induces a weak magnetic field and magnetic energy increases as the force
frequency deviates from the resonant frequency. This is opposite to the
intuition that a strong flow at resonance will induce a strong field. It is
because magnetic field nonlinearly couples with fluid flow in the
self-sustained dynamo and changes the resonance of driving force and inertial
wave.",1802.08284v2
2016-03-08,Bound and scattering states in harmonic waveguides in the vicinity of free space Feshbach resonances,"The two-body bound and scattering properties in an one-dimensional harmonic
waveguide close to free space magnetic Feshbach resonances are investigated
based on the local frame transformation approach within a single partial wave
approximation. An energy and magnetic field dependent free space phase shift is
adopted in the current theoretical framework. For both $s$- and $p$-wave
interaction, the least bound state in the waveguide dissociates into the
continuum at the resonant magnetic field where the effective one-dimensional
scattering length $a_{\rm 1D}$ diverges. Consequently, the association of atoms
into molecules in the waveguide occurs when the magnetic field is swept
adiabatically across the pole of $a_{\rm 1D}$. In the vicinity of broad
$s$-wave resonances, the resonant magnetic field is nearly independent on the
transverse confining frequency $\omega_{\perp}$ of the waveguide. Close to
$p$-wave and narrow $s$-wave resonances, the resonant magnetic field changes as
$\omega_{\perp}$ varies.",1603.02616v1
2021-08-10,Resonant photoproduction of ultrarelativistic electron-positron pairs on a nucleus in strong monochromatic light field,"For complete development of quantum electrodynamics in the presence of a
strong external field, the proper understanding of resonant processes and all
their peculiarities is essential. We present our attempt to analytically
investigate the resonant case of laser-assisted electron-positron pair
photoproduction on a nucleus. Due to the presence of external field, the
intermediate virtual particle may become real, herewith the second order
process in the fine structure constant effectively reduces into the two
successive first order processes. All inherent kinematics features were
discussed in details and the resonant differential cross section was obtained.
We established that the resonant energies of produced particles ambiguously
depend on the positron (channel A) or electron (channel B) outgoing angle, and
the certain minimal amount of absorbed wave photons are required for resonance
to happen. Furthermore, the resonant cross section significantly exceeds the
corresponding one in the absence of the external field within the particular
kinematic regions and consequently, the considered process can be used qua a
marker for probing theoretical predictions of quantum electrodynamics with
strong background field.",2108.04955v1
2017-03-06,Inverse resonance problems for the Schroedinger operator on the real line with mixed given data,"In this work, we study inverse resonance problems for the Schr\""odinger
operator on the real line with the potential supported in $[0,1]$. In general,
all eigenvalues and resonances can not uniquely determine the potential. (i) It
is shown that if the potential is known a priori on $[0,1/2]$, then the unique
recovery of the potential on the whole interval from all eigenvalues and
resonances is valid. (ii) If the potential is known a priori on $[0,a]$, then
for the case $a>1/2$, infinitely many eigenvalues and resonances can be missing
for the unique determination of the potential, and for the case $a<1/2$, all
eigenvalues and resonances plus a part of so-called sign-set can uniquely
determine the potential. (iii) It is also shown that all eigenvalues and
resonances, together with a set of logarithmic derivative values of
eigenfunctions and wave-functions at $1/2$, can uniquely determine the
potential.",1703.01708v2
2019-07-10,Intrinsic multipolar contents of nanoresonators for tailored scattering,"We introduce a theoretical and computational method to design resonant
objects, such as nanoantennas or meta-atoms, exhibiting tailored multipolar
responses. In contrast with common approaches that rely on a multipolar
analysis of the scattering response of an object upon specific excitations, we
propose to engineer the \textit{intrinsic} (i.e., excitation-independent)
multipolar content and spectral characteristics of the natural resonances -- or
quasinormal modes -- of the object. A rigorous numerical approach for the
multipolar decomposition of resonances at complex frequencies is presented,
along with an analytical model conveying a direct physical insight into the
multipole moments induced in the resonator. Our design strategy is illustrated
by designing a subwavelength optical resonator exhibiting a Janus resonance
that provides side-dependent coupling to waveguides over the full linewidth of
the resonance and on a wide angular range for linearly-polarized incident
planewaves. The method applies to all kinds of waves and may open new
perspectives for subwavelength-scale manipulation of scattering and emission.",1907.04598v3
2020-01-25,Asymptotic modeling of Helmholtz resonators including thermoviscous effects,"We systematically employ the method of matched asymptotic expansions to model
Helmholtz resonators, with thermoviscous effects incorporated starting from
first principles and with the lumped parameters characterizing the neck and
cavity geometries precisely defined and provided explicitly for a wide range of
geometries. With an eye towards modeling acoustic metasurfaces, we consider
resonators embedded in a rigid surface, each resonator consisting of an
arbitrarily shaped cavity connected to the external half-space by a small
cylindrical neck. The bulk of the analysis is devoted to the problem where a
single resonator is subjected to a normally incident plane wave; the model is
then extended using ""Foldy's method"" to the case of multiple resonators
subjected to an arbitrary incident field. As an illustration, we derive
critical-coupling conditions for optimal and perfect absorption by a single
resonator and a model metasurface, respectively.",2001.09353v1
2020-07-29,Spatial Fano resonance of a dielectric microsphere impinged by a Bessel beam,"General concept of Fano resonance is considered so that to show the
possibility of this resonance in space. Using a recently found solution for a
Bessel wave beam impinging a dielectric sphere, we analyze the electromagnetic
fields near a microsphere with different optical size and permittivity values.
We theoretically reveal a spatial Fano resonance when a resonant mode of the
sphere interferes with {an amount of } non-resonant modes. This resonance
results in a giant jump of the electric field behind the sphere impinged by the
first-order Bessel beam. The local minimum of the electromagnetic field turns
out to be noticeably distanced from the rear edge of the microsphere. However,
this is a near-field effect and we prove it. We also show that this effect can
be utilized for engineering a submicron optical trap with unusual and useful
properties.",2007.14867v2
2021-01-09,Semi-insulating 4H-SiC lateral bulk acoustic wave resonators,"Silicon carbide (SiC) excels in its outstanding mechanical properties, which
are widely studied in Microelectromechanical systems (MEMS). Recently, the
mechanical tuning of color centers in 4H-SiC has been demonstrated, broadening
its application in quantum spintronics. The strain generated in a mechanical
resonator can be used to manipulate the quantum state of the color center
qubit. This work reports a lateral overtone mechanical resonator fabricated
from a semi-insulating (SI) bulk 4H-SiC wafer. An aluminum nitride (AlN)
piezoelectric transducer on SiC is used to drive the resonance. The resonator
shows a series of modes with quality factors (Q) above 3000. An acoustic
reflector positioned at the anchor shows a 22% improvement in the Q at 300 MHz
resonance and suppresses the overtone modes away from it. This monolithic SiC
resonator allows optical access to the SiC color centers from both sides of the
wafer, enabling convenient setup in quantum measurements.",2101.03281v3
2021-03-26,Resonant binding of dielectric particles to metal surface without plasmonics,"High index dielectric spherical particle supports the high-$Q$ resonant Mie
modes that results in a regular series of sharp resonances in the radiation
pressure. A presence of perfectly conducting metal surface transforms the Mie
modes into the extremely high-$Q$ magnetic bonding or electric anti-bonding
modes for close approaching of the sphere to the surface. We show that the
electromagnetic plane wave with normal incidence results in repulsive or
attractive resonant optical forces relative to metal for excitation of the
electric bonding or magnetic anti-bonding resonant modes respectively. A
magnitude of resonant optical forces reaches order of one nano Newton of
magnitude for micron size of silicon particles and power of light $1mW/\mu m^2$
that exceeds the gravitational force by four orders. However what is the most
remarkable there are steady positions for the sphere between pulling and
pushing forces that gives rise to resonant binding of the sphere by metal
surface. A frequency of mechanical oscillations of particle around the
equilibrium positions reaches a magnitude of order MHz.",2103.14219v1
2021-06-10,Broadband resonant calibration-free complex permittivity retrieval of liquid solutions,"Material susceptibilities govern interactions between electromagnetic waves
and matter and are of a crucial importance for basic understanding of natural
phenomena and for tailoring practical applications. Here we present a new
calibration-free method for relative complex permittivity retrieval, which
allows using accessible and cheap apparatus and simplifies the measurement
process. The method combines advantages of resonant and non-resonant
techniques, allowing to extract parameters of liquids and solids in a broad
frequency range, where material's loss tangent is less than 0.5. The essence of
the method is based on exciting magnetic dipole resonance in a spherical sample
with variable dimensions. Size-dependent resonant frequencies and quality
factors of magnetic dipolar modes are mapped on real and imaginary parts of
permittivity by employing Mie theory. Samples are comprised of liquid
solutions, enclosed in stretchable covers, which allows changing the dimensions
continuously. This approach allows tuning magnetic dipolar resonance over a
wide frequency range, effectively making resonance retrieval method broadband.
The technique can be extended to powder and solid materials, depending on their
physical parameters, such as granularity and processability.",2106.09458v2
2022-05-06,Complementary-Switchable Dual-Mode SHF Scandium-Aluminum Nitride BAW Resonator,"This article presents a bulk acoustic wave (BAW) resonator with complementary
switchable operation in the first and second thickness extensional modes (TE1
and TE2) at 7.04 and 13.4 GHz. Two ferroelectric scandium aluminum nitride
(Sc0.28Al0.72N) layers are alternatively stacked with three molybdenum
electrodes, creating a laminated BAW resonator with independent switchability
of polarization in constituent transducers. This enables intrinsic
switchability of the resonator in TE1 and TE2 modes, when the ferroelectric
Sc0.28Al0.72N layers are poled in the same or opposite directions,
respectively. A generalized analytical proof of complementary switchable
operation, extended to laminated BAW resonators consisting of arbitrary number
of ScxAl1-xN layers, is presented. For the demonstrated prototype,
electromechanical coupling coefficients ( k2t ) of 10.1% and 10.7%, and quality
factors ( Q ) of 115 and 151, are measured for TE1 and TE2 modes, respectively,
when the resonator is configured in the corresponding operation states. Besides
showing intrinsically configurable operation in super-high-frequency regime
with high k2t and Q , a laminated Sc0.28Al0.72N BAW resonator exhibits
repeatable operation under switching cycles.",2205.03446v2
2023-10-12,Space-time symmetry and parametric resonance in dynamic mechanical systems,"Linear mechanical systems with time-modulated parameters can harbor
oscillations with amplitudes that grow or decay exponentially with time due to
the phenomenon of parametric resonance. While the resonance properties of
individual oscillators are well understood, identifying the conditions for
parametric resonance in systems of coupled oscillators remains challenging.
Here, we identify internal symmetries that arise from the real-valued and
symplectic nature of classical mechanics and determine the parametric resonance
conditions for periodically time-modulated mechanical metamaterials using these
symmetries. Upon including external symmetries, we find additional conditions
that prohibit resonances at some modulation frequencies for which parametric
resonance would be expected from the internal symmetries alone. In particular,
we analyze systems with space-time symmetry where the system remains invariant
after a combination of discrete translation in both space and time. For such
systems, we identify a combined space-time translation operator that provides
more information about the system than the Floquet operator does, and use it to
derive conditions for one-way amplification of traveling waves. Our results
establish an exact theoretical framework based on symmetries to engineer exotic
responses such as nonreciprocal transport and one-way amplification in
space-time modulated mechanical systems, and can be generalized to all physical
systems that obey space-time symmetry.",2310.08734v1
2023-11-15,Active elastic metamaterials with equidistant solely resonant bandgaps,"Elastic metamaterials are man-made structures with properties that transcend
naturally occurring materials. One predominant feature of elastic metamaterials
is locally resonant bandgaps, i.e., frequency ranges at which wave propagation
is blocked. Locally resonant bandgaps appear at relatively low frequency and
arise from the existence of periodically placed mechanical local resonators.
Typically, elastic metamaterials exhibit both locally resonant and
Bragg-scattering bandgaps, which can generally be different in width and
frequency ranges. This paper proposes two designs of active elastic
metamaterials that only exhibit locally resonant bandgaps, which are infinite
in number, evenly spaced in the frequency spectrum, and identical in width. The
mathematical model is established using the transfer matrix method and
synthesis of locally resonant bandgaps is achieved via an active elastic
support with carefully designed frequency-dependent stiffness. A single unit
cell of each proposed metamaterials is thoroughly studied, and its dispersion
relation is derived analytically, along with the periodically repeating bandgap
limits and widths. Following the dispersion analysis and bandgap parametric
studies, finite arrays of the proposed metamaterials are considered, and their
frequency response is calculated to verify the analytical predictions from
dispersion analyses.",2311.08959v2
2023-11-17,Resonance of Geometric Quantities and Hidden Symmetry in the Asymmetric Rabi Model,"We present the interesting resonance of two kinds of geometric quantities,
namely the Aharonov-Anandan (AA) phase and the time-energy uncertainty, and
reveal the relation between resonance and the hidden symmetry in the asymmetric
Rabi model by numerical and analytical methods. By combining the
counter-rotating hybridized rotating-wave method with time-dependent
perturbation theory, we solve systematically the time evolution operator and
then obtain the geometric phase of the Rabi model. In comparison with the
numerically exact solutions, we find that the analytical results accurately
describe the geometric quantities in a wide parameter space. We unveil the
effect of the bias on the resonance of geometric quantities, (1) the positions
of all harmonic resonances stemming from the shift of the Rabi frequency at the
presence of the bias; (2) the occurrence of even order harmonic resonance due
to the bias. When the driving frequency is equal to the subharmonics of the
bias, the odd higher-order harmonic resonances disappear. Finally, the hidden
symmetry has a resemblance to that of the quantum Rabi model with bias, which
indicates the quasienergy spectra are similar to the energy spectra of the
latter.",2311.10249v1
2023-12-22,Nucleon resonance parameters from Roy-Steiner equations,"A reliable determination of the pole parameters and residues of nucleon
resonances is notoriously challenging, given the required analytic continuation
into the complex plane. We provide a comprehensive analysis of such resonance
parameters accessible with Roy-Steiner equations for pion-nucleon scattering -
a set of partial-wave dispersion relations that combines the constraints from
analyticity, unitarity, and crossing symmetry - most prominently of the
$\Delta(1232)$ resonance. Further, we study the Roper, $N(1440)$, resonance,
which lies beyond the strict domain of validity, in comparison to Pad\'e
approximants, comment on the role of subthreshold singularities in the
$S$-wave, and determine the residues of the $f_0(500)$, $\rho(770)$, and
$f_0(980)$ resonances in the $t$-channel process $\pi\pi\to\bar NN$. The latter
allows us to test - for the first time fully model independently in terms of
the respective residues - universality of the $\rho(770)$ couplings and the
Goldberger-Treiman relation expected if the scalars behaved as dilatons, in
both cases revealing large deviations from the narrow-resonance limit.",2312.15015v1
2015-01-14,Long-lived Chaotic Orbital Evolution of Exoplanets in Mean Motion Resonances with Mutual Inclinations,"We present N-body simulations of resonant planets with inclined orbits that
show chaotically evolving eccentricities and inclinations that can persist for
at least 10 Gyr. A wide range of behavior is possible, from fast, low amplitude
variations to systems in which eccentricities reach 0.9999 and inclinations
179.9 degrees. While the orbital elements evolve chaotically, at least one
resonant argument always librates. We show that the HD 73526, HD 45364 and HD
60532 systems may be in chaotically-evolving resonances. Chaotic evolution is
apparent in the 2:1, 3:1 and 3:2 resonances, and for planetary masses from
lunar- to Jupiter-mass. In some cases, orbital disruption occurs after several
Gyr, implying the mechanism is not rigorously stable, just long-lived relative
to the main sequence lifetimes of solar-type stars. Planet-planet scattering
appears to yield planets in inclined resonances that evolve chaotically in
about 0.5% of cases. These results suggest that 1) approximate methods for
identifying unstable orbital architectures may have limited applicability, 2)
the observed close-in exoplanets may be produced during the high eccentricity
phases induced by inclined resonances, 3) those exoplanets' orbital planes may
be misaligned with the host star's spin axis, 4) systems with resonances may be
systematically younger than those without, 5) the distribution of period ratios
of adjacent planets detected via transit may be skewed due to inclined
resonances, and 6) potentially habitable planets in resonances may have
dramatically different climatic evolution than the Earth. The GAIA spacecraft
is capable of discovering giant planets in these types of orbits.",1501.03231v1
2021-07-02,Isovector giant monopole and quadrupole resonances in a Skyrme energy density functional approach with axial symmetry,"[Background] Giant resonance (GR) is a typical collective mode of vibration.
The deformation splitting of the isovector (IV) giant dipole resonance is well
established. However, the splitting of GRs with other multipolarities is not
well understood. [Purpose] I explore the IV monopole and quadrupole excitations
and attempt to obtain the generic features of IV giant resonances in deformed
nuclei by investigating the neutral and charge-exchange channels
simultaneously. [Method] I employ a nuclear energy-density functional (EDF)
method: the Skyrme-Kohn-Sham-Bogoliubov and the quasiparticle random-phase
approximation are used to describe the ground state and the transition to
excited states. [Results] I find the concentration of the monopole strengths in
the energy region of the isobaric analog or Gamow-Teller resonance irrespective
of nuclear deformation, and the appearance of a high-energy giant resonance
composed of the particle-hole configurations of $2\hbar \omega_0$ excitation.
Splitting of the distribution of the strength occurs in the giant monopole and
quadrupole resonances due to deformation. The lower $K$ states of quadrupole
resonances appear lower in energy and possess the enhanced strengths in the
prolate configuration, and vice versa in the oblate configuration, while the
energy ordering depending on $K$ is not clear for the $J=1$ and $J=2$
spin-quadrupole resonances. [Conclusions] The deformation splitting occurs
generously in the giant monopole and quadrupole resonances. The $K$-dependence
of the quadrupole transition strengths is largely understood by the anisotropy
of density distribution.",2107.00867v1
2001-04-22,Parametric generation of second sound in superfluid helium: linear stability and nonlinear dynamics,"We report the experimental studies of a parametric excitation of a second
sound (SS) by a first sound (FS) in a superfluid helium in a resonance cavity.
The results on several topics in this system are presented: (i) The linear
properties of the instability, namely, the threshold, its temperature and
geometrical dependencies, and the spectra of SS just above the onset were
measured. They were found to be in a good quantitative agreement with the
theory. (ii) It was shown that the mechanism of SS amplitude saturation is due
to the nonlinear attenuation of SS via three wave interactions between the SS
waves. Strong low frequency amplitude fluctuations of SS above the threshold
were observed. The spectra of these fluctuations had a universal shape with
exponentially decaying tails. Furthermore, the spectral width grew continuously
with the FS amplitude. The role of three and four wave interactions are
discussed with respect to the nonlinear SS behavior. The first evidence of
Gaussian statistics of the wave amplitudes for the parametrically generated
wave ensemble was obtained. (iii) The experiments on simultaneous pumping of
the FS and independent SS waves revealed new effects. Below the instability
threshold, the SS phase conjugation as a result of three-wave interactions
between the FS and SS waves was observed. Above the threshold two new effects
were found: a giant amplification of the SS wave intensity and strong resonance
oscillations of the SS wave amplitude as a function of the FS amplitude.
Qualitative explanations of these effects are suggested.",0104414v1
2022-08-01,Tidally Forced Planetary Waves in the Tachocline of Solar-like Stars,"Can atmospheric waves in planet-hosting solar-like stars substantially
resonate to tidal forcing? Substantially at a level of impacting the space
weather or even of being dynamo-relevant? In particular, low-frequency Rossby
waves, which have been detected in the solar near-surface layers, are
predestined at responding to sunspot cycle-scale perturbations. In this paper,
we seek to address these questions as we formulate a forced wave model for the
tachocline layer, which is widely considered as the birthplace of several
magnetohydrodynamic planetary waves, i.e., Rossby, inertia-gravity
(Poincar\'{e}), Kelvin, Alfv\'{e}n and gravity waves. The tachocline is modeled
as a shallow plasma atmosphere with an effective free surface on top that we
describe within the Cartesian $\beta$-plane approximation. As a novelty to
former studies, we equip the governing equations with a conservative tidal
potential and a linear friction law to account for dissipation. We combine the
linearized governing equations to one decoupled wave equation, which
facilitates an easily approachable analysis. Analytical results are presented
and discussed within several interesting free, damped and forced wave limits
for both mid-latitude and equatorially trapped waves. For the idealized case of
a single tide generating body following a circular orbit, we derive an explicit
analytic solution that we apply to our Sun for estimating leading-order
responses to Jupiter. Our analysis reveals that Rossby waves resonating to
low-frequency perturbations can potentially reach considerable velocity
amplitudes in the order of $10^1 - 10^2\, {\rm cm}\, {\rm s}^{-1}$, which,
however, strongly rely on the yet unknown total dissipation.",2208.00644v1
2011-01-10,Radiation of caustic beams from a collapsing bullet,"Collapse of an intense (2+1)-dimensional wave packet in a medium with cubic
nonlinearity and a two-dimensional dispersion of an order higher than parabolic
is studied both theoretically and experimentally. The carrier waves are
microwave backward volume spin waves which propagate in a stripe made from a
thin ferrimagnetic film and the packet is a spin-wave bullet. We show that
before being self-destroyed the bullet irradiates untrapped dispersive waves,
which is in agreement with a previous theoretical prediction. Since, in
addition, the ferromagnetic medium is characterized by an induced uniaxial
anisotropy, this radiation takes the form of narrow beams of continuous waves
at very specific angles to its propagation direction. Based on our theoretical
calculations we find that these beams are caustic beams and the angles are the
characteristic spin-wave caustic angles modified by the motion of the source.",1101.1696v2
2018-05-18,Spinning Particles in Twisted Gravitational Wave Spacetimes,"Twisted gravitational waves (TGWs) are nonplanar waves with twisted rays that
move along a fixed direction in space. We study further the physical
characteristics of a recent class of Ricci-flat solutions of general relativity
representing TGWs with wave fronts that have negative Gaussian curvature. In
particular, we investigate the influence of TGWs on the polarization of test
electromagnetic waves and on the motion of classical spinning test particles in
such radiation fields. To distinguish the polarization effects of twisted waves
from plane waves, we examine the theoretical possibility of existence of
spin-twist coupling and show that this interaction is generally consistent with
our results.",1805.07080v6
2018-06-11,Explicit inclusion of spin-orbit contribution in THSR wave function,"The Tohsaki-Horiuchi-Schuck-Roepke (THSR) wave function has been successfully
used for the studies of gas-like nature of alpha clusters in various nuclei
including the so-called Hoyle state of 12C and four alpha states of 16O. In
standard alpha cluster models, however, each alpha cluster wave function has
spin zero because of its spatial symmetry and antisymmetrization effect. Thus
the non-central interactions do not contribute, and this situation is the same
in the THSR wave function. In this work, the spin-orbit contribution, which is
found to be quite important at short alpha-alpha distances, is taken into
account in the THSR wave function by combing it with antisymmetrized quasi
cluster model (AQCM). The application to 12C is presented. The
multi-integration in the original THSR wave function is carried out by using
Monte Carlo technique, which is called Monte Carlo THSR wave function. For the
nucleon-nucleon interaction, the Tohsaki interaction, which contains
finite-range three-body terms and simultaneously reproduces the saturation
properties of nuclear systems, the alpha-alpha scattering phase shift, and the
size and binding energy of 4He, is adopted.",1806.03817v1
2020-04-07,Nonreciprocal Dzyaloshinskii-Moriya magnetoacoustic waves,"We study the interaction of surface acoustic waves with spin waves in
ultra-thin CoFeB/Pt bilayers. Due to the interfacial Dzyaloshinskii-Moriya
interaction (DMI), the spin wave dispersion is non-degenerate for oppositely
propagating spin waves in CoFeB/Pt. In combination with the additional
nonreciprocity of the magnetoacoustic coupling itself, highly nonreciprocal
acoustic wave transmission through the magnetic film is observed. We
systematically characterize the magnetoacoustic wave propagation in a thickness
series of CoFeB($d$)/Pt samples as a function of magnetic field magnitude and
direction, and at frequencies up to 7 GHz. We quantitatively model our results
to extract the strength of the DMI and magnetoacoustic driving fields.",2004.03535v2
2023-09-20,On spin optics for gravitational waves lensed by a rotating object,"We study gravitational lensing of gravitational waves taking into account the
spin of a graviton coupled with a dragged spacetime made by a rotating object.
We decompose the phase of gravitational waves into helicity-dependent and
independent components with spin optics, analyzing waves whose wavelengths are
shorter than the curvature radius of a lens object. We analytically confirm
that the trajectory of gravitational waves splits depending on the helicity,
generating additional time delay and elliptical polarization onto the
helicity-independent part. We exemplify monotonic gravitational waves lensed by
a Kerr black hole and derive the analytical expressions of corrections in phase
and magnification. The corrections are enhanced for longer wavelengths,
potentially providing a novel probe of rotational properties of lens objects in
low-frequency gravitational-wave observations in the future.",2309.11024v2
2006-08-30,Spin-quadrupole ordering of spin-3/2 ultracold fermionic atoms in optical lattices in the one-band Hubbard model,"Based on a generalized one-band Hubbard model, we study magnetic properties
of Mott insulating states for ultracold spin-3/2 fermionic atoms in optical
lattices. When the \textit{s}-wave scattering lengths for the total spin
$S=2,0$ satisfy conditions $a_{2}>a_{0}>0$, we apply a functional integral
approach to the half filled case, where the spin-quadrupole fluctuations
dominate. On a 2D square lattice, the saddle point solution yields a staggered
spin-quadrupole ordering at zero temperature with symmetry breaking from SO(5)
to SO(4). Both spin and spin-quadrupole static structure factors are
calculated, displaying highly anisotropic spin antiferromagnetic fluctuations
and antiferroquadrupole long-range correlations, respectively. When Gaussian
fluctuations around the saddle point are taken into account, spin-quadrupole
density waves with a linear dispersion are derived. Compared with the spin
density waves in the half filled spin-1/2 Hubbard model, the quadrupole density
wave velocity is saturated in the strong-coupling limit, and there are no
transverse spin-quadrupole mode couplings, as required by the SO(4) invariance
of the effective action. Finally, in the strong-coupling limit of the model
Hamiltonian, we derive the effective hyperfine spin-exchange interactions for
the Mott insulating phases in the quarter filled and half filled cases,
respectively.",0608673v3
2015-10-12,"On equation of state for the ""thermal"" part of the spin current: Pauli principle contribution in the spin wave spectrum in cold fermion system","Spin evolution opened a large field in quantum plasma research. The spin
waves in plasmas were considered among new phenomena considered in spin-1/2
quantum plasmas. The spin density evolution equation found by means of the
many-particle quantum hydrodynamics shows existence of the ""thermal"" part of
the spin current, which is an analog of the thermal pressure, or the Fermi
pressure for degenerate electron gas, existing in the Euler equation. However,
this term has been dropped, since there has not been found any equation of
state for the thermal part of the spin current (TPSC), like we have for the
pressure. In this paper we derive the equation of state for the TPSC and apply
it for study of spectrum of collective excitations in spin-1/2 quantum plasmas.
We focus our research on the spectrum of spin waves, since this spectrum is
affected by the thermal part of the spin current. We consider two kinds of
plasmas: electron-ion plasma with motionless ions and degenerate electrons, and
degenerate electron-positron plasmas. We also present the non-linear Pauli
equation with the spinor pressure term containing described effects. The
thermal part of the flux of spin current existing in the spin current evolution
equation is also derived. We also consider the contribution of the TPSC in the
grand generalized vorticity evolution.",1510.03468v1
2016-05-10,New investigations on the transverse spin of structured optical fields,"Guided waves and surface waves can be taken as two typical examples of
structured optical fields with the transverse spin. Analytical derivations are
developed to demonstrate that (i) guided waves also carry the transverse spin
that depends on the mean direction of propagation, which may have important
applications in spin-dependent unidirectional optical interfaces; (ii) the
quantization form of the transverse spin is for the first time revealed, which
is not obvious and related to an ellipticity; (iii) from a unified point of
view, the transverse spin can be attributed to the presence of an effective
rest mass of structured optical fields; (iv) the transverse spin can also be
described by the spin matrix of the photon field; (v) unlike a free optical
field whose spin projection on the propagation direction is the only
observable, owing to the effective rest mass, the spin projection of structured
optical fields on other directions is also an observable, such that one can
develop an optical analogy of spintronics. A preliminary idea about the
potential applications of the transverse spin is presented, but an in-depth and
complete study will be presented in our next work.",1605.03103v2
2021-04-19,Experimental observation of transverse spin of plasmon polaritons in a single-crystalline silver nanowire,"We report the experimental observation of the transverse spin and associated
spin-momentum locking of surface plasmon polaritons (SPPs) excited in a
plasmonic single crystalline silver nanowire (AgNW). In contrast to the SPPs
excited in metal films, the electromagnetic field components of the evanescent
SPP mode propagating along the long axis ($x$ axis) of the NW can decay along
two longitudinal planes ($x$-$y$ and $x$-$z$ planes), resulting in two
orthogonal transverse spin components ($s_z$ and $s_y$). Analysis of the
opposite circular polarization components of the decaying SPP mode signal in
the longitudinal plane ($x$-$y$) reveals spin dependent biasing of the signal
and hence the existence of transverse spin component ($s_z$). The corresponding
transverse spin density ($s_3$) in the Fourier plane reveals spin-momentum
locking, where the helicity of the spin is dictated by the wave-vector
components of the SPP evanescent wave. Further, the results are corroborated
with three-dimensional numerical calculations. The presented results showcase
how a chemically prepared plasmonic AgNW can be harnessed to study optical
spins in evanescent waves, and can be extrapolated to explore sub-wavelength
effects including directional spin coupling and optical nano-manipulation.",2104.09303v2
2020-01-16,The Low Effective Spin of Binary Black Holes and Implications for Individual Gravitational-Wave Events,"While the Advanced LIGO and Virgo gravitational-wave experiments now
regularly observe binary black hole mergers, the evolutionary origin of these
events remains a mystery. Analysis of the binary black hole spin distribution
may shed light on this mystery, offering a means of discriminating between
different binary formation channels. Using the data from Advanced LIGO and
Virgo's first and second observing runs, here we seek to carefully characterize
the distribution of effective spin among binary black holes, hierarchically
measuring the distribution's mean $\mu$ and variance $\sigma^2$ while
accounting for selection effects and degeneracies between spin and other black
hole parameters. We demonstrate that the known population of binary black holes
have spins that are both small, with $\mu \sim 0$, and very narrowly
distributed, with $\sigma^2 \leq 0.07$ at 95% credibility. We then explore what
these ensemble properties imply about the spins of individual binary black hole
mergers, re-analyzing existing gravitational-wave events with a
population-informed prior on their effective spin. The binary black hole
GW170729, which previously excluded effective spin equal to zero, is now
consistent with zero effective spin at ~10% credibility. More broadly, we find
that uninformative spin priors generally yield overestimates for the effective
spin magnitudes of compact binary mergers.",2001.06051v2
2023-07-18,Effect of Spin Orbit Coupling in non-centrosymmetric half-Heusler alloys,"Spin-orbit coupled electronic structure of two representative non-polar
half-Heusler alloys, namely 18 electron compound CoZrBi and 8 electron compound
SiLiIn have been studied in details. An excursion through the Brillouin zone of
these alloys from one high symmetry point to the other revealed rich local
symmetry of the associated wave vectors resulting in non-trivial spin splitting
of the bands and consequent diverse spin textures in the presence of spin-orbit
coupling. Our first principles calculations supplemented with low energy
$\boldsymbol{k.p}$ model Hamiltonian revealed the presence of linear
Dresselhaus effect at the X point having $D_{2d}$ symmetry and Rashba effect
with both linear and non-linear terms at the L point with $C_{3v}$ point group
symmetry. Interestingly we have also identified non-trivial Zeeman spin
splitting at the non-time reversal invariant W point and a pair of
non-degenerate bands along the path $\Gamma$ to L displaying vanishing spin
polarization due to the non-pseudo polar point group symmetry of the wave
vectors. Further a comparative study of CoZrBi and SiLiIn suggest, in addition,
to the local symmetry of the wave vectors, important role of the participating
orbitals in deciding the nature and strength of spin splitting. Our
calculations identify half-Heusler compounds with heavy elements displaying
diverse spin textures may be ideal candidate for spin valleytronics where spin
textures can be controlled by accessing different valleys around the high
symmetry k-points.",2308.03760v2
2024-01-11,Gravitational waves carry information beyond effective spin parameters but it is hard to extract,"Gravitational wave observations of binary black hole mergers probe their
astrophysical origins via the binary spin, namely the spin magnitudes and
directions of each component black hole, together described by six degrees of
freedom. However, the emitted signals primarily depend on two effective spin
parameters that condense the spin degrees of freedom to those parallel and
those perpendicular to the orbital plane. Given this reduction in
dimensionality between the physically relevant problem and what is typically
measurable, we revisit the question of whether information about the component
spin magnitudes and directions can successfully be recovered via
gravitational-wave observations, or if we simply extrapolate information about
the distributions of effective spin parameters.To this end, we simulate three
astrophysical populations with the same underlying effective-spin distribution
but different spin magnitude and tilt distributions, on which we conduct full
individual-event and population-level parameter estimation. We find that
parameterized population models can indeed qualitatively distinguish between
populations with different spin magnitude and tilt distributions at current
sensitivity. However, it remains challenging to either accurately recover the
true distribution or to diagnose biases due to model misspecification. We
attribute the former to practical challenges of dealing with high-dimensional
posterior distributions, and the latter to the fact that each individual event
carries very little information about the full six spin degrees of freedom.",2401.05613v1
2001-05-09,Spin tunneling via dislocations in Mn-12 acetate crystals,"We show that dislocations should be the main source of spin tunneling in
Mn-12 crystals. Long-range strains caused by dislocations produce broad
distribution of relaxation times that has been seen in many experiments. When
the external magnetic field is applied along the c-axis of the crystal, local
rotations of the magnetic anisotropy axis due to dislocations result in the
effective local transverse magnetic field that unfreezes odd tunneling
resonances. Scaling law is derived that provides universal description of spin
tunneling for all resonances.",0105195v1
2001-10-17,Evaluation of the Bychkov- Rashba Field from the Spin Resonance of Electrons in a Si Quantum Well,"From spin resonance of two-dimensional (2D) conduction electrons in a
modulation doped SiGe/Si/SiGe quantum well structure we find a 2D anisotropy of
both the line broadening (dephasing time) and the g-factor. We show that these
can be explained consistently in terms of the Bychkov-Rashba (BR) field which
here is the dominant coupling between electron motion and spin. We obtain a BR
parameter of alpha = 1.1 e-12 eV cm - three orders of magnitude smaller as
compared to III-V wells. Extrapolating for low electron concentrations we
obtain a g-factor of the Si conduction band of 2.00073+/-0.00010.",0110342v1
2002-10-26,Dynamic exchange coupling in magnetic bilayers,"A long-ranged dynamic interaction between ferromagnetic films separated by
normal-metal spacers is reported, which is communicated by nonequilibrium spin
currents. It is measured by ferromagnetic resonance (FMR) and explained by an
adiabatic spin-pump theory. In FMR the spin-pump mechanism of spatially
separated magnetic moments leads to an appreciable increase in the FMR line
width when the resonance fields are well apart, and results in a dramatic
line-width narrowing when the FMR fields approach each other.",0210588v2
2003-09-11,Spin Dynamics of t-J Model on Triangular Lattice,"We study the spin dynamics of t-J model on triangular lattice in the
Slave-Boson-RPA scheme in light of the newly discovered superconductor
Na$_{x}$CoO$_{2}$. We find resonant peak in the dynamic spin susceptibility in
the $d+id^{^{\prime}}$-wave superconducting state for both hole and electron
doping in large doping range. We find the geometrical frustration inherent of
the triangular lattice provide us a unique opportunity to discriminate the
SO(5) and RPA-like intepretation of the origin of the resonant peak.",0309275v1
2004-07-23,Electron Spin Resonance of SrCu2(BO3)2 at High Magnetic Field,"We calculate the electron spin resonance (ESR) spectra of the
quasi-two-dimensional dimer spin liquid SrCu2(BO3)2 as a function of magnetic
field B. Using the standard Lanczos method, we solve a Shastry-Sutherland
Hamiltonian with additional Dzyaloshinsky-Moriya (DM) terms which are crucial
to explain different qualitative aspects of the ESR spectra. In particular, a
nearest-neighbor DM interaction with a non-zero D_z component is required to
explain the low frequency ESR lines for B || c. This suggests that crystal
symmetry is lowered at low temperatures due to a structural phase transition.",0407632v1
2004-09-22,Wigner Function Formalism for Zero Magnetic Field Spin Dependent Resonant Tunneling Structures,"We develop a Wigner function representation of the quantum transport theory
of the conduction band electrons in Rashba effect resonant tunneling structures
with a phonon bath. In narrow band gap heterostructures, spin splitting occurs
mainly as a result of inversion asymmetry in the spatial dependence of the
potential or as a result of external electric field. This ""zero magnetic field
spin splitting"" is due to the Rashba term in the effective mass Hamiltonian.
The quantum transport equations are derived using multi-band non-equilibrium
Green's function formulation in generalized Kadanoff-Baym ansatz.",0409595v2
2005-02-18,Electron spin resonance on a 2-dimensional electron gas in a single AlAs quantum well,"Direct electron spin resonance (ESR) on a high mobility two dimensional
electron gas in a single AlAs quantum well reveals an electronic $g$-factor of
1.991 at 9.35 GHz and 1.989 at 34 GHz with a minimum linewidth of 7 Gauss. The
ESR amplitude and its temperature dependence suggest that the signal originates
from the effective magnetic field caused by the spin orbit-interaction and a
modulation of the electron wavevector caused by the microwave electric field.
This contrasts markedly to conventional ESR that detects through the microwave
magnetic field.",0502450v1
2006-01-26,Tunable conductance of magnetic nanowires with structured domain walls,"We show that in a magnetic nanowire with double magnetic domain walls,
quantum interference results in spin-split quasistationary states localized
mainly between the domain walls. Spin-flip-assisted transmission through the
domain structure increases strongly when these size-quantized states are tuned
on resonance with the Fermi energy, e.g. upon varying the distance between the
domain walls which results in resonance-type peaks of the wire conductance.
This novel phenomena is shown to be utilizable to manipulate the spin density
in the domain vicinity. The domain walls parameters are readily controllable
and the predicted effect is hence exploitable in spintronic devices.",0601620v1
2006-05-05,Cavity quantum electrodynamics with semiconductor double-dot molecules on a chip,"We describe a coherent control technique for coupling electron spin states
associated with semiconductor double-dot molecule to a microwave stripline
resonator on a chip. We identify a novel regime of operation in which strong
interaction between a molecule and a resonator can be achieved with minimal
decoherence, reaching the so-called strong coupling regime of cavity QED. We
describe potential applications of such a system, including low-noise coherent
electrical control, fast QND measurements of spin states, and long-range spin
coupling.",0605144v1
2006-05-23,Suppression of telegraph noise in a CPP spin valve by an oscillating spin torque: Numerical study,"The phenomenon of stochastic resonance (SR) has been mainly studied in
one-dimensional systems with additive noise. We show that in higher dimensional
systems and in the presence of multiplicative noise, a non-linear magnetic
system with a strongly periodic current can show behavior similar to that of SR
but only for frequencies below the ferromagnetic resonance (FMR) frequency of
the system. Such a phenomena can provide an effective way to suppress low
frequency noise in spin valve magnetic sensors.",0605585v1
2006-09-08,Quantum Dynamics of Molecular Nanomagnets in a Resonant Cavity and the Maser Effect,"We study the dynamics of molecular nanomagnets through a fully quantum
mechanical model describing high-spin and high-anisotropy magnetic molecules
subjected to a time-dependent magnetic field along the quantization axis, which
continuously inverts the population of spin states. Crystals of molecular
nanomagnets placed inside a resonant cavity interact with a quantized
electromagnetic field. Relaxation of excited states takes place by means of
spin-photon interaction, allowing stimulated emission of radiation and creating
a maser effect.",0609205v1
1997-03-19,Spin-Dependent Twist-Four Matrix Elements from g_1 Data in the Resonance Region,"Matrix elements of spin-dependent twist-four operators are extracted from
recent data on the spin-dependent g_1 structure function of the proton and
deuteron in the resonance region. We emphasize the need to include the elastic
contributions to the first moments of the structure functions at Q^2 < 2 GeV^2.
The coefficients of the 1/Q^2 corrections to the Ellis-Jaffe sum rules are
found to be 0.04 \pm 0.02 and 0.03 \pm 0.04 GeV^2 for the proton and neutron,
respectively.",9703363v1
1998-12-17,Effective Lagrangian Study of $γp \to K^+ Λ$ (spin 3/2 resonances and their off-shell effects),"The purpose of the present discussion is to supplement the talk, by B.~Saghai
at this workshop, on the study of the electromagnetic production of strangeness
on the nucleon based upon effective Lagrangian methods. Here we focus on the
proper treatment of the spin 3/2 resonances and their associated effects due to
the spin 1/2 component of the corresponding fields when they are {\it off the
mass shell}.",9812048v1
2004-10-18,Applicability of shape parameterizations for giant dipole resonance in warm and rapidly rotating nuclei,"We investigate how well the shape parameterizations are applicable for
studying the giant dipole resonance (GDR) in nuclei, in the low temperature
and/or high spin regime. The shape fluctuations due to thermal effects in the
GDR observables are calculated using the actual free energies evaluated at
fixed spin and temperature. The results obtained are compared with Landau
theory calculations done by parameterizing the free energy. We exemplify that
the Landau theory could be inadequate where shell effects are dominating. This
discrepancy at low temperatures and high spins are well reflected in GDR
observables and hence insists on exact calculations in such cases.",0410075v1
2000-03-30,Novel approach for spin-flipping a stored polarized beam,"The traditional method of spin-flipping a stored polarized beam is based on
slowly crossing an rf induced depolarizing resonance. This paper discusses a
novel approach where the polarization reversal is achieved by trapping the beam
polarization into a stable spin-flipping motion on top of the rf induced
resonance at a half-revolution frequency.",0003104v1
1999-09-09,Solid-State Nuclear Spin Quantum Computer Based on Magnetic Resonance Force Microscopy,"We propose a nuclear spin quantum computer based on magnetic resonance force
microscopy (MRFM). It is shown that an MRFM single-electron spin measurement
provides three essential requirements for quantum computation in solids: (a)
preparation of the ground state, (b) one- and two- qubit quantum logic gates,
and (c) a measurement of the final state. The proposed quantum computer can
operate at temperatures up to 1K.",9909033v1
1999-10-06,Quantum stochastic resonance in driven spin-boson system with stochastic limit approximation,"After a brief review of stochastic limit approximation with spin-boson system
from physical points of view, amplification phenomenon-stochastic resonance
phenomenon-in driven spin-boson system is observed which is helped by the
quantum white noise introduced through the stochastic limit approximation. The
shift in frequency of the system due to the interaction with the
environment-Lamb shift-has an important role in these phenomena.",9910025v1
2002-10-07,Single-Spin Measurement and Decoherence in Magnetic Resonance Force Microscopy,"We consider a simple version of a cyclic adiabatic inversion (CAI) technique
in magnetic resonance force microscopy (MRFM). We study the problem: What
component of the spin is measured in the CAI MRFM? We show that the
non-destructive detection of the cantilever vibrations provides a measurement
of the spin component along the effective magnetic field. This result is based
on numerical simulations of the Hamiltonian dynamics (the Schrodinger equation)
and the numerical solution of the master equation.",0210043v1
2004-02-24,Sequential Probability Ratio Test for the detection of a single electron spin in the OSCAR setup,"The MRFM device is a powerful setup for manipulating single electron spin in
resonance in a magnetic field. However, the real time observation of a
resonating spin is still an issue because of the very low SNR of the output
signal. This paper investigates the usability and the efficiency of sequential
detection schemes (the Sequential Probability Ratio Test) to decrease the
required integration time, in comparison to standard fixed time detection
schemes.",0402181v1
2004-11-16,Adiabatic Quantum State Manipulation of Single Trapped Atoms,"We use microwave induced adiabatic passages for selective spin flips within a
string of optically trapped individual neutral Cs atoms. We
position-dependently shift the atomic transition frequency with a magnetic
field gradient. To flip the spin of a selected atom, we optically measure its
position and sweep the microwave frequency across its respective resonance
frequency. We analyze the addressing resolution and the experimental robustness
of this scheme. Furthermore, we show that adiabatic spin flips can also be
induced with a fixed microwave frequency by deterministically transporting the
atoms across the position of resonance.",0411120v2
2005-03-25,Simulation of a Heisenberg XY- chain and realization of a perfect state transfer algorithm using liquid nuclear magnetic resonance,"The three- spin chain with Heisenberg XY- interaction is simulated in a
three- qubit nuclear magnetic resonance (NMR) quantum computer. The evolution
caused by the XY- interaction is decomposed into a series of single- spin
rotations and the $J$- coupling evolutions between the neighboring spins. The
perfect state transfer (PST) algorithm proposed by M. Christandl et al [Phys.
Rev. Lett, 92, 187902(2004)] is realized in the XY- chain.",0503199v2
2006-05-02,Projective measurement in nuclear magnetic resonance,"It is demonstrated that nuclear magnetic resonance experiments using
pseudopure spin states can give possible outcomes of projective quantum
measurement and probabilities of such outcomes. The physical system is a
cluster of six dipolar-coupled nuclear spins of benzene in a liquid-crystalline
matrix. For this system with the maximum total spin S=3, the results of
measuring $S_X$ are presented for the cases when the state of the system is one
of the eigenstates of $S_Z$.",0605032v1
2007-07-03,Spin-orbit-assisted electron-phonon interaction and the magnetophonon resonance in semiconductor quantum wells,"We introduce a spin-orbit assisted electron-phonon (e-ph) coupling mechanism
for carriers in semiconductor quantum wells and predict qualitatively the form
and shape of anticrossings between the cyclotron resonance (CR) and optical (LO
and TO) phonons. Since this e-ph interaction involves the electron spin it
makes the predicted TO-CR anticrossing dependent on the filling factor and
therefore on the polarization of the 2D electron gas in the quantum well.",0707.0342v2
2007-08-30,NMR method for amplification of single spin state,"Amplification of a single spin state using nuclear magnetic resonance (NMR)
techniques in a rotating frame is considered. The main aim is to investigate
the efficient of various schemes for quantum detection. Results of numerical
simulation of the time dependence of individual and total nuclear polarizations
for one-, two-, and three-dimensional configurations of the spin systems are
presented.",0708.4090v1
2007-11-26,Dynamic Nuclear Polarization in Silicon Microparticles,"We report record high Si-29 spin polarization obtained using dynamic nuclear
polarization in microcrystalline silicon powder. Unpaired electrons in this
silicon powder are due to dangling bonds in the amorphous region of this
intrinsically heterogeneous sample. Si-29 nuclei in the amorphous region become
polarized by forced electron-nuclear spin flips driven by off-resonant
microwave radiation while nuclei in the crystalline region are polarized by
spin diffusion across crystalline boundaries. Hyperpolarized silicon
microparticles have long T1 relaxation times and could be used as tracers for
magnetic resonance imaging.",0711.4076v2
2008-04-01,Entanglement and transport anomalies in nanowires,"A shallow potential well in a near-perfect quantum wire will bind a
single-electron and behave like a quantum dot, giving rise to spin-dependent
resonances of propagating electrons due to Coulomb repulsion and Pauli
blocking. It is shown how this may be used to generate full entanglement
between static and flying spin-qubits near resonance in a two-electron system
via singlet or triplet spin-filtering. In a quantum wire with many electrons,
the same pairwise scattering may be used to explain conductance, thermopower
and shot-noise anomalies, provided the temperature/energy scale is sufficiently
high for Kondo-like many-body effects to be negligible.",0804.0141v1
2008-07-11,Probing the spin polarization of current by soft X-ray imaging of current-induced magnetic vortex dynamics,"Time-resolved soft X-ray transmission microscopy is applied to image the
current-induced resonant dynamics of the magnetic vortex core realized in a
micronsized Permalloy disk. The high spatial resolution better than 25 nm
enables us to observe the resonant motion of the vortex core. The result also
provides the spin polarization of the current to be 0.67 +/-0.16 for Permalloy
by fitting the experimental results with an analytical model in the framework
of the spin-transfer torque.",0807.1782v1
2008-10-27,Coherent spin radiation by magnetic nanomolecules and nanoclusters,"The peculiarities of coherent spin radiation by magnetic nanomolecules is
investigated by means of numerical simulation. The consideration is based on a
microscopic Hamiltonian taking into account realistic dipole interactions.
Superradiance can be realized only when the molecular sample is coupled to a
resonant electric circuit. The feedback mechanism allows for the achievement of
a fast spin reversal time and large radiation intensity. The influence on the
level of radiation, caused by sample shape and orientation, is analysed. The
most powerful coherent radiation is found to occur for an elongated sample
directed along the resonator magnetic field.",0810.4822v1
2009-02-13,Charge pumping and the colored thermal voltage noise in spin valves,"Spin pumping by a moving magnetization gives rise to an electric voltage over
a spin valve. Thermal fluctuations of the magnetization manifest themselves as
increased thermal voltage noise with absorption lines at the ferromagnetic
resonance frequency and/or zero frequency. The effect depends on the
magnetization configuration and can be of the same order of magnitude as the
Johnson-Nyquist thermal noise. Measuring colored voltage noise is an
alternative to ferromagnetic resonance experiments for nano-scale ferromagnetic
circuits.",0902.2389v2
2009-10-29,Spin Hamiltonians with resonating-valence-bond ground states,"Quantum dimer models exhibit quantum critical points and liquid states when
the ground state is the resonating-valence bond (RVB) state. We construct
SU(2)-invariant spin-1/2 Hamiltonians with the same RVB ground state. The main
technical obstacle overcome is the fact that different ""dimer"" configurations
in the spin model are not orthogonal to each other. We show that the physics
depends on how dimers are related to the spins, and find a Hamiltonian that may
be quantum critical.",0910.5708v3
2010-04-23,Charge and spin state readout of a double quantum dot coupled to a resonator,"State readout is a key requirement for a quantum computer. For
semiconductor-based qubit devices it is usually accomplished using a separate
mesoscopic electrometer. Here we demonstrate a simple detection scheme in which
a radio-frequency resonant circuit coupled to a semiconductor double quantum
dot is used to probe its charge and spin states. These results demonstrate a
new non-invasive technique for measuring charge and spin states in quantum dot
systems without requiring a separate mesoscopic detector.",1004.4047v1
2010-05-17,Resonator-assisted entangling gate for singlet-triplet spin qubits in nanowire double quantum dots,"We propose a resonator-assisted entangling gate for spin qubits with high
fidelity. Each spin qubit corresponds to two electrons in a nanowire double
quantum dot, with the singlet and one of the triplets as the logical qubit
states. The gate is effected by virtual charge dipole transitions. We include
noise in our model to show feasibility of the scheme under current experimental
conditions.",1005.2856v1
2010-06-29,Electron spin resonance measurements of a demagnetizing field on the surface of metal samples,"By comparing the signals of electron spin resonance (ESR) from two crystals
of a diamond (spin-labels) the demagnetizing field of the Co, Fe, and Ni
samples in the shape of strongly elongated ellipsoids of revolution (disks) has
been measured. The magnetic permeabilities of the metals in the external
magnetic field corresponding to the ESR of the broken chemical bonds in a
natural diamond irradiated with fast reactor neutrons have been determined.",1006.5668v1
2010-08-28,Resonant Inelastic X-ray Scattering on Spin-Orbit Coupled Insulating Iridates,"We determine how the elementary excitations of iridium-oxide materials, which
are dominated by a strong relativistic spin-orbit coupling, appear in Resonant
Inelastic X-ray Scattering (RIXS). Whereas the RIXS spectral weight at the L2
x-ray edge vanishes, we find it to be strong at the L3-edge. Applying this to
Sr2IrO4, we observe that RIXS, besides being sensitive to local doublet to
quartet transitions, meticulously maps out the strongly dispersive delocalized
excitations of the low-lying spin-orbit doublets.",1008.4862v1
2010-10-26,Spin Nutation Induced by Atomic Motion in a Magnetic Lattice,"An atom moving in a spatially periodic field experiences a temporary periodic
perturbation and undergoes a resonance transition between atomic internal
states when the transition frequency is equal to the atomic velocity divided by
the field period. We demonstrated that spin nutation was induced by this
resonant transition in a polarized rubidium (Rb) atomic beam passing through a
magnetic lattice. The lattice was produced by current flowing through an array
of parallel wires crossing the beam. This array structure, reminiscent of a
multiwire chamber for particle detection, allowed the Rb beam to pass through
the lattice at a variety of incident angles. The dephasing of spin nutation was
reduced by varying the incident angle.",1010.5319v1
2011-01-31,Beam spin asymmetry in deeply virtual $π$ production,"An interpretation of the beam spin azimuthal asymmetries measured at JLAB in
deep exclusive electroproduction of charged and neutral pions is presented. The
model combines a Regge pole approach with the effect of nucleon resonances. The
$s$- and $u$-channel contributions are described using a dual Bloom-Gilman
connection between the exclusive form factors and inclusive deep inelastic
structure functions. The results are in agreement with data provided the
excitations of nucleon resonances are taken into account.",1101.6042v1
2011-05-16,On the line shape of the electrically detected ferromagnetic resonance,"This work reviews and examines two particular issues related with the new
technique of electrical detection of ferromagnetic resonance (FMR). This
powerful technique has been broadly applied for studying magnetization and spin
dynamics over the past few years. The first issue is the relation and
distinction between different mechanisms that give rise to a photovoltage via
FMR in composite magnetic structures, and the second is the proper analysis of
the FMR line shape, which remains the ""Achilles heel"" in interpreting
experimental results, especially for either studying the spin pumping effect or
quantifying the spin Hall angles via the electrically detected FMR.",1105.3236v1
2011-07-29,Electron spin resonance shift in spin ladder compounds,"We analyze the effects of different coupling anisotropies in spin-1/2 ladder
on the Electron Spin Resonance (ESR) shift. Combining a perturbative expression
in the anisotropies with temperature dependent Density Matrix Renormalization
Group (T-DMRG) computation of the short range correlations, we provide the full
temperature and magnetic field evolution of the ESR paramagnetic shift. We show
that for well chosen parameters the ESR shift can be in principle used to
extract quantitatively the anisotropies and, as an example, discuss the
material $\mathrm{(C_5H_{12}N)_2CuBr_4}$ (BPCB).",1107.5965v2
2011-09-22,Molecular structure refinement by direct fitting of atomic coordinates to experimental ESR spectra,"An attempt is made to bypass spectral analysis and fit internal coordinates
of radicals directly to experimental liquid- and solid-state electron spin
resonance (ESR) spectra. We take advantage of the recently introduced
large-scale spin dynamics simulation algorithms and of the fact that the
accuracy of quantum mechanical calculations of ESR parameters has improved to
the point of quantitative correctness. Partial solutions are offered to the
local minimum problem in spectral fitting and to the problem of spin
interaction parameters (hyperfine couplings, chemical shifts, etc.) being very
sensitive to distortions in molecular geometry.",1109.4815v1
2011-11-23,Spin-orbit Interaction induced Singlet-Triplet Resonant Raman Transitions in Quantum-dot Helium,"From our theoretical studies of resonant Raman transitions in two-electron
quantum dots (artificial helium atoms) we show that in this system, the
singlet-triplet Raman transitions are allowed (in polarized configuration) only
in the presence of spin-orbit interactions. With an increase of the applied
magnetic field this transition dominates over the singlet-singlet and
triplet-triplet transitions. This intriguing effect can therefore be utilized
to tune Raman transitions as well as the spin-orbit coupling in few-electron
quantum dots.",1111.5460v1
2015-04-23,Effects of the interplay between the orbital and spin currents in electroexcitation of light nuclei,"The interplay between the orbital and spin currents in (e,e') excitations of
light nuclei is discussed. The microscopic analysis of E1 and M2 resonances was
performed within the particle-core coupling approximation (PCC) of the shell
model. The comparison of the theoretical results with the available
experimental data has shown that the studies of relative contributions of the
orbital and different spin components of the nuclear current into the
excitation of EJ and MJ resonances could be useful for the identification of
their configurational structure.",1504.06032v1
2015-12-01,Discrete and Continuous Systems of Logic in Nuclear Magnetic Resonance,"We implement several non-binary logic systems using the spin dynamics of
nuclear spins in nuclear magnetic resonance (NMR). The NMR system is a suitable
test system because of its high degree of experimental control; findings from
NMR implementations are relevant for other computational platforms exploiting
particles with spin, such as electrons or photons. While we do not expect the
NMR system to become a practical computational device, it is uniquely useful to
explore strengths and weaknesses of unconventional computational approaches,
such as non-binary logic.",1512.00521v1
2016-01-25,"Theory of electron spin resonance in bulk topological insulators Bi2Se3, Bi2Te3 and Sb2Te3","We report a theoretical study of electron spin resonance in bulk topological
insulators, such as Bi2Se3, Bi2Te3 and Sb2Te3. Using the effective four-band
model, we find the electron energy spectrum in a static magnetic field and
determine the response to electric and magnetic dipole perturbations,
represented by oscillating electric and magnetic fields perpendicular to the
static field. We determine the associated selection rules and calculate the
absorption spectra. This enables us to separate the effective orbital and spin
degrees of freedom and to determine the effective g-factors for electrons and
holes.",1601.06507v1
2016-10-21,Electromotive forces generated in 3d-transition ferromagnetic metal films themselves under their ferromagnetic resonance,"We report the electromotive force (EMF) properties generated in 3d-transition
ferromagnetic metal (FM = Fe, Co, and Ni80Fe20) films themselves under their
ferromagnetic resonance (FMR). For Fe and Co films, the EMF due to the
anomalous-Hall effect is dominantly generated under their FMR. Meanwhile, for a
Ni80Fe20 film, the EMF due to the inverse spin-Hall effect in the Ni80Fe20 film
itself under the FMR is mainly generated. This tendency is qualitatively
explained with differences of the spin polarization, the spin Hall
conductivity, the anomalous Hall conductivity, the magnetization saturation,
and the resistivity of the FM films.",1610.06695v2
2016-12-19,Thickness dependence study of current-driven ferromagnetic resonance in Y3Fe5O12/heavy metal bilayers,"We use ferromagnetic resonance to study the current-induced torques in
YIG/heavy metal bilayers. YIG samples with thickness varying from 14.8 nm to 80
nm, with Pt or Ta thin film on top, are measured by applying a microwave
current into the heavy metals and measuring the longitudinal DC voltage
generated by both spin rectification and spin pumping. From a symmetry analysis
of the FMR lineshape and its dependence on YIG thickness, we deduce that the
Oersted field dominates over spin-transfer torque in driving magnetization
dynamics.",1612.06111v1
2017-02-10,Quasi-continuous variable quantum computation with collective spins in multi-path interferometers,"Collective spins of large atomic samples trapped inside optical resonators
can carry quantum information that can be processed in a way similar to quantum
computation with continuous variables. It is shown here that by combining the
resonators in multi-path interferometers one can realize coupling between
different samples, and that polynomial Hamiltonians can be constructed by
repeated spin rotations and twisting induced by dispersive interaction of the
atoms with light. Application can be expected in efficient simulation of
quantum systems.",1702.03124v2
2017-10-11,Ultra-cold Collisions between Spin-Orbit-Coupled Dipoles: General Formalism and Universality,"A theoretical study of the low-energy scattering properties of two aligned
identical bosonic and fermionic dipoles in the presence of isotropic spin-orbit
coupling (SOC) is presented. A general treatment of particles with arbitrary
(pseudo-) spin is given in the framework of multi-channel scattering. At
ultracold temperatures and away from shape resonances or closed-channel
dominated resonances, the cross-section can be well described within the Born
approximation to within corrections due to the s-wave scattering. We compare
our findings with numerical calculations and find excellent agreement.",1710.03901v2
2016-11-27,Probing Electron Spin Resonance in Monolayer Graphene,"The precise value of the $g$-factor in graphene is of fundamental interest
for all spin-related properties and their application. We investigate monolayer
graphene on a Si/SiO2 substrate by resistively detected electron spin resonance
(ESR). Surprisingly, the magnetic moment and corresponding g-factor of
1.952+/-0.002 is insensitive to charge carrier type, concentration, and
mobility.",1611.08782v1
2020-05-19,Instability in the Hartmann--Hahn double resonance,"The Hartmann-Hahn technique allows sensitivity enhancement of magnetic
resonance imaging and spectroscopy by coupling the spins under study to another
spin species that is externally driven. Here we theoretically study the coupled
spins' dynamics, and find that for a certain region of driving parameters the
system becomes unstable. The required conditions for making this region of
instability becoming experimentally accessible are discussed.",2005.09298v3
2021-03-16,Optically detected flip-flops between different spin ensembles in diamond,"We employ the technique of optical detection of magnetic resonance to study
dipolar interaction in diamond between nitrogen-vacancy color centers of
different crystallographic orientations and substitutional nitrogen defects. We
demonstrate optical measurements of resonant spin flips-flips (second Larmor
line), and flip-flops between different spin ensembles in diamond. In addition,
the strain coupling between the nitrogen-vacancy color centers and bulk
acoustic modes is studied using optical detection. Our findings may help
optimizing cross polarization protocols, which, in turn, may allow improving
the sensitivity of diamond-based detectors.",2103.08994v1
2022-02-01,Nuclear matrix elements for neutrinoless double beta decays and spin-dipole giant resonances,"Nuclear matrix elements (NMEs) for neutrinoless double beta decays (DBDs) are
required for studying neutrino physics beyond the standard model by DBD. The
experimental spin-dipole (SD) giant resonance energy and the SD strength are
shown for the first time to be closely related to the DBD-NME, and are used for
studying the spin-isospin correlation and the quenching of the axial-vector
coupling. So they are used to help the theoretical model calculation of the
DBD-NME.",2202.00361v2
2022-10-02,Spin-orbit coupling and Kondo resonance in Co adatom on Cu(100) surface: DFT+ED study,"We report density functional theory plus exact diagonalization of the
multi-orbital Anderson impurity model calculations for the Co adatom on the top
of Cu(001) surface. For the Co atom $d$-shell occupation $n_d \approx$ 8, a
singlet many-body ground state and Kondo resonance are found, when the
spin-orbit coupling is included in the calculations. The differential
conductance is evaluated in a good agreement with the scanning tuneling
microscopy measurements. The results illustrate the essential role which the
spin-orbit coupling is playing in a formation of Kondo singlet for the
multi-orbital impurity in low dimensions.",2210.00600v1
2022-10-20,Theory of resonant Raman scattering due to spin-flips of resident charge carries and excitons in perovskite semiconductors,"We have developed a theory of Raman scattering with single and double spin
flips of localized resident electrons and holes as well as nonequilibrium
localized excitons in semiconductor perovskite crystals under optical
excitation in the resonant exciton region. Scattering mechanisms involving
localized excitons, biexcitons and exciton polaritons as intermediate states
has been examined, the spin-flip Raman scattering by polaritons being a novel
mechanism. The derived equations are presented in the invariant form allowing
one for the analysis of the dependence of scattering efficiency on the
polarization of the initial and scattered light and on the orientation of the
external magnetic field.",2210.11202v1
2023-01-18,Purcell enhancement of single-photon emitters in silicon,"Individual spins that are coupled to telecommunication photons offer unique
promise for distributed quantum information processing once a coherent and
efficient spin-photon interface can be fabricated at scale. We implement such
an interface by integrating erbium dopants into a nanophotonic silicon
resonator. We achieve spin-resolved excitation of individual emitters with <
0.1 GHz spectral diffusion linewidth. Upon resonant driving, we observe optical
Rabi oscillations and single-photon emission with a 78-fold Purcell
enhancement. Our results establish a promising new platform for quantum
networks.",2301.07753v2
2016-05-18,Standing magnetic wave on Ising ferromagnet: Nonequilibrium phase transition,"The dynamical response of an Ising ferromagnet to a plane polarised standing
magnetic field wave is modelled and studied here by Monte Carlo simulation in
two dimensions. The amplitude of standing magnetic wave is modulated along the
direction x. We have detected two main dynamical phases namely, pinned and
oscillating spin clusters. Depending on the value of field amplitude the system
is found to undergo a phase transition from oscillating spin cluster to pinned
as the system is cooled down. The time averaged magnetisation over a full cycle
of magnetic field oscillations is defined as the dynamic order parameter. The
transition is detected by studying the temperature dependences of the variance
of the dynamic order parameter, the derivative of the dynamic order parameter
and the dynamic specific heat. The dependence of the transition temperature on
the magnetic field amplitude and on the wavelength of the magnetic field wave
is studied at a single frequency. A comprehensive phase boundary is drawn in
the plane described by the temperature and field amplitude for two different
wavelengths of the magnetic wave. The variation of instantaneous line
magnetisation during a period of magnetic field oscillation for standing wave
mode is compared to those for the propagating wave mode. Also the probability
that a spin at any site, flips, is calculated. The above mentioned variations
and the probability of spin flip clearly distinguish between the dynamical
phases formed by propagating magnetic wave and by standing magnetic wave in an
Ising ferromagnet.",1605.05643v2
2024-01-04,Symmetry of the coupling between surface acoustic waves and spin waves in synthetic antiferromagnets,"Synthetic antiferromagnets host spin waves that are highly tunable. It is of
practical interest to analyze the symmetry of their coupling to surface
acoustic waves with the design of hybrid devices in view. For this we calculate
the layer-resolved susceptibility tensor of a synthetic antiferromagnet, the
effective magneto-elastic and magneto-rotation fields associated to a
travelling elastic wave, and the power irreversibly transferred by the elastic
wave to the magnetic layers. We consider Rayleigh-type surface acoustic waves:
(a) that travel in an elastically isotropic, non-piezoelectric substrate, or
(b) that propagate along the X direction at the surface of a Z-cut LiNbO$_3$
substrate, or (c) that are guided in a thin Z-cut LiNbO$_3$ film grown on a
sapphire substrate. In particular, we show that the complementary angular
dependencies of the acoustic and optical spin wave modes in synthetic
antiferromagnets makes it possible to excite spin waves for any relative
orientation of magnetization and acoustic wavevector. In addition, we discuss
the symmetries of the driving fields and of the energy transferred to the
magnetic degree of freedom. We evidence new interaction channels coupling the
magnetization eigenmodes when elastic anisotropy and piezoelectricity of the
substrate are considered.",2401.02263v1
2006-01-30,Electric Dipole Induced Spin Resonance in Quantum Dots,"An alternating electric field, applied to a quantum dot, couples to the
electron spin via the spin-orbit interaction. We analyze different types of
spin-orbit coupling known in the literature and find two efficient mechanisms
of spin control in quantum dots. The linear in momentum Dresselhaus and Rashba
spin-orbit couplings give rise to a fully transverse effective magnetic field
in the presence of a Zeeman splitting at lowest order in the spin-orbit
interaction. The cubic in momentum Dresselhaus terms are efficient in a quantum
dot with non-harmonic confining potential and give rise to a spin-electric
coupling proportional to the orbital magnetic field. We derive an effective
spin Hamiltonian, which can be used to implement spin manipulation on a
timescale of $10 {\rm ns}$ with the current experimental setups.",0601674v2
2004-12-01,A new mechanism for electron spin echo envelope modulation,"Electron spin echo envelope modulation (ESEEM) has been observed for the
first time from a coupled hetero-spin pair of electron and nucleus in liquid
solution. Previously, modulation effects in spin echo experiments have only
been described in liquid solutions for a coupled pair of homonuclear spins in
NMR or a pair of resonant electron spins in EPR. We observe low-frequency ESEEM
(26 and 52 kHz) due to a new mechanism present for any electron spin with S>1/2
that is hyperfine coupled to a nuclear spin. In our case these are electron
spin (S=3/2) and nuclear spin (I=1) in the endohedral fullerene N@C60. The
modulation is shown to arise from second order effects in the isotropic
hyperfine coupling of an electron and 14N nucleus.",0412002v1
2007-09-16,Measurement of Rashba and Dresselhaus spin-orbit magnetic fields,"Spin-orbit coupling is a manifestation of special relativity. In the
reference frame of a moving electron, electric fields transform into magnetic
fields, which interact with the electron spin and lift the degeneracy of
spin-up and spin-down states. In solid-state systems, the resulting spin-orbit
fields are referred to as Dresselhaus or Rashba fields, depending on whether
the electric fields originate from bulk or structure inversion asymmetry,
respectively. Yet, it remains a challenge to determine the absolute value of
both contributions in a single sample. Here we show that both fields can be
measured by optically monitoring the angular dependence of the electrons' spin
precession on their direction of movement with respect to the crystal lattice.
Furthermore, we demonstrate spin resonance induced by the spin-orbit fields. We
apply our method to GaAs/InGaAs quantum-well electrons, but it can be used
universally to characterise spin-orbit interactions in semiconductors,
facilitating the design of spintronic devices.",0709.2509v1
2010-03-26,Quantum-dot-spin single-photon interface,"Using background-free detection of spin-state-dependent resonance
fluorescence from a single-electron charged quantum dot with an efficiency of
0:1%, we realize a single spin-photon interface where the detection of a
scattered photon with 300 picosecond time resolution projects the quantum dot
spin to a definite spin eigenstate with fidelity exceeding 99%. The bunching of
resonantly scattered photons reveals information about electron spin dynamics.
High-fidelity fast spin-state initialization heralded by a single photon
enables the realization of quantum information processing tasks such as
non-deterministic distant spin entanglement. Given that we could suppress the
measurement back-action to well below the natural spin-flip rate, realization
of a quantum non-demolition measurement of a single spin could be achieved by
increasing the fluorescence collection efficiency by a factor exceeding 20
using a photonic nanostructure.",1003.5195v3
2010-08-20,Nuclear spin cooling using Overhauser field selective coherent population trapping,"Hyperfine interactions with a nuclear spin environment fundamentally limit
the coherence properties of confined electron spins in the solid-state. Here,
we show that a quantum interference effect in optical absorption from two
electronic spin states of a solid-state emitter can be used to prepare the
surrounding environment of nuclear spins in well-defined states, thereby
suppressing electronic spin dephasing. The evolution of the coupled
electron-nuclei system into a coherent population trapping state by optical
excitation induced nuclear spin diffusion can be described in terms of Levy
flights, in close analogy with sub-recoil laser cooling of atoms. The large
difference in electronic and nuclear time scales simultaneously allow for a
measurement of the magnetic field produced by nuclear spins, making it possible
to turn the lasers that cause the anomalous spin diffusion process off when the
strength of the resonance fluorescence reveals that the nuclear spins are in
the desired narrow state.",1008.3507v1
2010-09-26,Detection and quantification of inverse spin Hall effect from spin pumping in permalloy/normal metal bilayers,"Spin pumping is a mechanism that generates spin currents from ferromagnetic
resonance (FMR) over macroscopic interfacial areas, thereby enabling sensitive
detection of the inverse spin Hall effect that transforms spin into charge
currents in non-magnetic conductors. Here we study the spin-pumping-induced
voltages due to the inverse spin Hall effect in permalloy/normal metal bilayers
integrated into coplanar waveguides for different normal metals and as a
function of angle of the applied magnetic field direction, as well as microwave
frequency and power. We find good agreement between experimental data and a
theoretical model that includes contributions from anisotropic
magnetoresistance (AMR) and inverse spin Hall effect (ISHE). The analysis
provides consistent results over a wide range of experimental conditions as
long as the precise magnetization trajectory is taken into account. The spin
Hall angles for Pt, Pd, Au and Mo were determined with high precision to be
$0.013\pm0.002$, $0.0064\pm0.001$, $0.0035\pm0.0003$ and $-0.0005\pm0.0001$,
respectively.",1009.5089v1
2012-03-16,Adiabatic Passage and Spin Locking in Tm$^{3+}$:YAG,"In low concentration Tm$^{3+}$:YAG, we observe efficient adiabatic rapid
passage (ARP) of thulium nuclear spin over flipping times much longer than
$T_2$. Efficient ARP with long flipping time has been observed in monoatomic
solids for decades and has been analyzed in terms of spin temperature and of
the thermodynamic equilibrium of a coupled spin ensemble. In low-concentration
impurity-doped crystals the spin temperature concept may be questioned. A
single spin model should be preferred since the impurity ions are weakly
coupled together but interact with the numerous off-resonant matrix ions that
originate the spin-spin relaxation. The experiment takes place in the context
of quantum information investigation, involving impurity-doped crystals, spin
hyperpolarization by optical pumping, and optical detection of the spin
evolution.",1203.3753v2
2012-04-24,Sensing distant nuclear spins with a single electron spin,"We experimentally demonstrate the use of a single electronic spin to measure
the quantum dynamics of distant individual nuclear spins from within a
surrounding spin bath. Our technique exploits coherent control of the electron
spin, allowing us to isolate and monitor nuclear spins weakly coupled to the
electron spin. Specifically, we detect the evolution of distant individual
carbon-13 nuclear spins coupled to single nitrogen vacancy centers in a diamond
lattice with hyperfine couplings down to a factor of 8 below the electronic
spin bare dephasing rate. Potential applications to nanoscale magnetic
resonance imaging and quantum information processing are discussed.",1204.5483v2
2012-06-15,All-optical control of the spin state in the NV-center in diamond,"We describe an all-optical scheme for spin manipulation in the ground-state
triplet of the negatively charged nitrogen-vacancy (NV) center in diamond.
Virtual optical excitation from the 3A_2 ground state into the 3E excited state
allows for spin rotations by virtue of the spin-spin interaction in the
two-fold orbitally degenerate excited state. We derive an effective Hamiltonian
for optically induced spin-flip transitions within the ground state spin
triplet due to off-resonant optical pumping. Furthermore, we investigate the
spin qubit formed by the Zeeman sub-levels with spin projection m_S = 0 and m_S
= -1 along the NV axis around the ground state level anticrossing with regard
to full optical control of the electron spin.",1206.3505v1
2012-11-06,Experimental Verification of Comparability between Spin-Orbit and Spin-Diffusion Lengths,"We experimentally confirmed that the spin-orbit lengths of noble metals
obtained from weak anti-localization measurements are comparable to the spin
diffusion lengths determined from lateral spin valve ones. Even for metals with
strong spin-orbit interactions such as Pt, we verified that the two methods
gave comparable values which were much larger than those obtained from recent
spin torque ferromagnetic resonance measurements. To give a further evidence
for the comparability between the two length scales, we measured the disorder
dependence of the spin-orbit length of copper by changing the thickness of the
wire. The obtained spin-orbit length nicely follows a linear law as a function
of the diffusion coefficient, clearly indicating that the Elliott-Yafet
mechanism is dominant as in the case of the spin diffusion length.",1211.1222v2
2013-08-16,Plasmonic generation of spin currents,"Surface plasmons, free-electron collective oscillations in metallic
nanostructures, provide abundant routes to manipulate light-electron
interactions that can localize light energy and alter electromagnetic field
distributions at subwavelength scales. The research field of plasmonics thus
integrates nano-photonics with electronics. In contrast, electronics is also
entering a new era of spintronics, where spin currents play a central role in
driving devices. However, plasmonics and spin-current physics have so far been
developed independently. Here, we demonstrate the generation of spin currents
by surface plasmons. Using Au nanoparticles embedded in a Pt/BiY2Fe5O12 bilayer
film, we show that, when the Au nanoparticles fulfill the
surface-plasmon-resonance condition, spin currents are generated across the
Pt/BiY2Fe5O12 interface. This plasmonic spin pumping results from
nonequilibrium states of spins excited by surface-plasmon-induced evanescent
electromagnetic fields in the BiY2Fe5O12 layer. Such plasmonic spin pumping
will invigorate research on spin-current physics, and pave the way for future
spin-based plasmonic devices.",1308.3532v2
2014-07-25,Spin pumping using an Ni80Fe20 thin film annealed in a magnetic field,"Spin pumping controlled with the ferromagnetic resonance of an Ni80Fe20 thin
film annealed in a magnetic field was performed in order to investigate the
simple and efficient generation method of the pure spin current. At the
spin-pumping using the Ni80Fe20 on an annealed Pd/Ni80Fe20 stacked structure,
the electromotive force due to the inverse spin-Hall effect (ISHE) in the Pd
was found to be 30% stronger than that without annealing. When the angle
between the directions of localized magnetic moments in the Ni80Fe20 film and
the external magnetic field in the spin-pumping is zero, the spin injection
efficiency into the Pd layer, i.e., the spin current density generated in the
Pd layer can be the maximum. The annealing in a magnetic field is a convenient
technique for increasing the spin current density generated by the spin
pumping.",1407.7028v3
2014-07-30,Room Temperature Spin Pumping in Topological Insulator Bi2Se3,"Three-dimensional (3D) topological insulators are known for their strong
spin-orbit coupling and the existence of spin-textured topological surface
states which could be potentially exploited for spintronics. Here, we
investigate spin pumping from a metallic ferromagnet (CoFeB) into a 3D
topological insulator (Bi2Se3) and demonstrate successful spin injection from
CoFeB into Bi2Se3 and the direct detection of the electromotive force generated
by the inverse spin Hal effect (ISHE) at room temperature. The spin pumping,
driven by the magnetization dynamics of the metallic ferromagnet, introduces a
spin current into the topological insulator layer, resulting in a broadening of
the ferromagnetic resonance (FMR) linewidth. We find that the FMR linewidth
more than quintuples, the spin mixing conductance can be as large as
3.4*10^20m^-2 and the spin Hall angle can be as large as 0.23 in the Bi2Se3
layer.",1407.7940v1
2014-09-12,Protecting a solid-state spin from decoherence using dressed spin states,"Dressed spin states, a spin coupling to continuous radiation fields, can
fundamentally change how a spin responds to magnetic fluctuations. Using
dressed spin states, we were able to protect an electron spin in diamond from
decoherence. Dressing a spin with resonant microwaves at a coupling rate near 1
MHz leads to a 50 times reduction in the linewidth of the spin transition,
limited by transit-time broadening. The spin decoherence and the energy level
structure of the dressed states were probed with optical
coherent-population-trapping processes. Compared with dynamical decoupling,
where effects of the bath are averaged out at specific times, the dressed state
provides a continuous protection from decoherence.",1409.3786v1
2015-01-27,An experimental demonstration of room-temperature spin transport in n-type Germanium epilayers,"We report the first experimental demonstration of room-temperature spin
transport in n-type Ge epilayers grown on a Si(001) substrate. By utilizing
spin pumping under ferromagnetic resonance, which inherently endows a spin
battery function for semiconductors connected with the ferromagnet, a pure spin
current is generated in the n-Ge at room temperature. The pure spin current is
detected by using the inverse spin Hall effect of either Pt or Pd electrode on
the n-Ge. A theoretical model including a geometrical contribution allows to
estimate a spin diffusion length in n-Ge at room temperature to be 660 nm. The
temperature dependence of the spin relaxation time provides evidence for
Elliott-Yafet spin relaxation mechanism.",1501.06691v1
2015-05-29,Topological Surface States Originated Spin-Orbit Torques in Bi2Se3,"Three dimensional topological insulator bismuth selenide (Bi2Se3) is expected
to possess strong spin-orbit coupling and spin-textured topological surface
states, and thus exhibit a high charge to spin current conversion efficiency.
We evaluate spin-orbit torques in Bi2Se3/Co40Fe40B20 devices at different
temperatures by spin torque ferromagnetic resonance measurements. As
temperature decreases, the spin-orbit torque ratio increases from ~ 0.047 at
300 K to ~ 0.42 below 50 K. Moreover, we observe a significant out-of-plane
torque at low temperatures. Detailed analysis indicates that the origin of the
observed spin-orbit torques is topological surface states in Bi2Se3. Our
results suggest that topological insulators with strong spin-orbit coupling
could be promising candidates as highly efficient spin current sources for
exploring next generation of spintronic applications.",1505.07937v1
2015-08-31,All electrical manipulation of magnetization dynamics in a ferromagnet by antiferromagnets with anisotropic spin Hall effects,"We investigate spin-orbit torques of metallic CuAu-I-type antiferromagnets
using spin-torque ferromagnetic resonance tuned by a dc-bias current. The
observed spin torques predominantly arise from diffusive transport of spin
current generated by the spin Hall effect. We find a growth-orientation
dependence of the spin torques by studying epitaxial samples, which may be
correlated to the anisotropy of the spin Hall effect. The observed anisotropy
is consistent with first-principles calculations on the intrinsic spin Hall
effect. Our work demonstrates large tunable spin-orbit effects in
magnetically-ordered materials.",1508.07906v2
2015-09-22,Rare-earth triangular lattice spin liquid: a single-crystal study of YbMgGaO$_{4}$,"YbMgGaO$_{4}$, a structurally perfect two-dimensional triangular lattice with
odd number of electrons per unit cell and spin-orbit entangled effective
spin-1/2 local moments of Yb$^{3+}$ ions, is likely to experimentally realize
the quantum spin liquid ground state. We report the first experimental
characterization of single crystal YbMgGaO$_{4}$ samples. Due to the spin-orbit
entanglement, the interaction between the neighboring Yb$^{3+}$ moments depends
on the bond orientations and is highly anisotropic in the spin space. We carry
out the thermodynamic and the electron spin resonance measurements to confirm
the anisotropic nature of the spin interaction as well as to quantitatively
determine the couplings. Our result is a first step towards the theoretical
understanding of the possible quantum spin liquid ground state in this system
and sheds new lights on the search of quantum spin liquids in strong spin-orbit
coupled insulators.",1509.06766v1
2015-12-18,Interplay between resonant tunneling and spin precession oscillations in all-electric all-semiconductor spin transistors,"We investigate the transmission properties of a spin transistor coupled to
two quantum point contacts acting as spin injector and detector. In the
Fabry-Perot regime, transport is mediated by quasibound states formed between
tunnel barriers. Interestingly, the spin-orbit interaction of the Rashba type
can be tuned in such a way that nonuniform Rashba fields can point along
distinct directions in different points of the sample. We discuss both
spin-conserving and spin-flipping transitions as the spin-orbit angle of
orientation increases from parallel to antiparallel configurations. Spin
precession oscillations are clearly seen as a function of the length of the
central channel. Remarkably, we find that these oscillations combine with the
Fabry-Perot motion giving rise to quasiperiodic transmissions in the purely
one-dimensional case. Furthermore, we consider the more realistic case of a
finite width in the transverse direction and find that the coherent
oscillations become deteriorated for moderate values of the spin-orbit
strength. Our results then determine the precise role of the Rashba
intersubband coupling potential in the Fabry-Perot-Datta-Das intermixed
oscillations.",1512.05958v2
2016-02-17,Fractional Spin Fluctuation as a Precursor of Quantum Spin Liquids: Majorana Dynamical Mean-Field Study for the Kitaev Model,"Experimental identification of quantum spin liquids remains a challenge, as
the pristine nature is to be seen in asymptotically low temperatures. We here
theoretically show that the precursor of quantum spin liquids appears in the
spin dynamics in the paramagnetic state over a wide temperature range. Using
the cluster dynamical mean-field theory and the continuous-time quantum Monte
Carlo method, which are newly developed in the Majorana fermion representation,
we calculate the dynamical spin structure factor, relaxation rate in nuclear
magnetic resonance, and magnetic susceptibility for the honeycomb Kitaev model
whose ground state is a canonical example of the quantum spin liquid. We find
that dynamical spin correlations show peculiar temperature and frequency
dependence even below the temperature where static correlations saturate. The
results provide the experimentally-accessible symptoms of the fluctuating
fractionalized spins evincing the quantum spin liquids.",1602.05253v2
2016-08-02,Spintronics of Organometal Trihalide Perovskites,"The family of organometal trihalide perovskite (OTP), CH3NH3PbX3 (where X is
halogen) has recently revolutionized the photovoltaics field and shows promise
in a variety of optoelectronic applications. The characteristic spin properties
of charge and neutral excitations in OTPs are influenced by the large
spin-orbit coupling of the Pb atoms, which may lead to spin-based device
applications. Here we report the first studies of pure spin-current and
spin-aligned carrier injection in OTP spintronics devices using spin-pumping
and spin-injection, respectively. We measure a relatively large
inverse-spin-Hall effect using pulsed microwave excitation in OTP devices at
resonance with a ferromagnetic substrate, from which we derive room temperature
spin diffusion length, lambda_sd~9nm; and low-temperature giant
magnetoresistance in OTP-based spin-valves from which we estimate
lambda_sd~85nm.",1608.00993v1
2017-12-21,Dynamics of a single ion spin impurity in a spin-polarized atomic bath,"We report on observations of spin dynamics in single Yb$^+$ ions immersed in
a cold cloud of spin-polarized $^6$Li atoms. This species combination has been
proposed to be the most suitable system to reach the quantum regime in atom-ion
experiments. For $^{174}$Yb$^+$, we find that the atomic bath polarizes the
spin of the ion by 93(4)\,\% after a few Langevin collisions, pointing to
strong spin-exchange rates. For the hyperfine ground states of $^{171}$Yb$^+$,
we also find strong rates towards spin polarization. However, relaxation
towards the $F=0$ ground state occurs after 7.7(1.5) Langevin collisions. We
investigate spin impurity atoms as possible source of apparent spin-relaxation
leading us to interpret the observed spin-relaxation rates as an upper limit.
Using ab initio electronic structure and quantum scattering calculations, we
explain the observed rates and analyze their implications for the possible
observation of Feshbach resonances between atoms and ions once the quantum
regime is reached.",1712.07873v2
2018-07-31,Spin absorption at ferromagnetic-metal/platinum-oxide interface,"We investigate the absorption of a spin current at a
ferromagnetic-metal/Pt-oxide interface by measuring current-induced
ferromagnetic resonance. The spin absorption was characterized by the magnetic
damping of the heterostructure. We show that the magnetic damping of a
Ni$_{81}$Fe$_{19}$ film is clearly enhanced by attaching Pt-oxide on the
Ni$_{81}$Fe$_{19}$ film. The damping enhancement is disappeared by inserting an
ultrathin Cu layer between the Ni$_{81}$Fe$_{19}$ and Pt-oxide layers. These
results demonstrate an essential role of the direct contact between the
Ni$_{81}$Fe$_{19}$ and Pt-oxide to induce sizable interface spin-orbit
coupling. Furthermore, the spin-absorption parameter of the
Ni$_{81}$Fe$_{19}$/Pt-oxide interface is comparable to that of intensively
studied heterostructures with strong spin-orbit coupling, such as an oxide
interface, topological insulators, metallic junctions with Rashba spin-orbit
coupling. This result illustrates strong spin-orbit coupling at the
ferromagnetic-metal/Pt-oxide interface, providing an important piece of
information for quantitative understanding the spin absorption and spin-charge
conversion at the ferromagnetic-metal/metallic-oxide interface.",1807.11806v1
2018-04-16,Spin manipulation and spin dephasing in quantum dot integrated with a slanting magnetic field,"A slanting magnetic field is usually used to realize a slight hybridization
between the spin and orbital degrees of freedom in a semiconductor quantum dot,
such that the spin is manipulable by an external oscillating electric field.
Here we show that, the longitudinal slanting field mediates a longitudinal
driving term in the electric-dipole spin resonance, such that the spin
population inversion exhibits a modulated Rabi oscillation. Fortunately, we can
reduce this modulation by increasing the static magnetic field. The
longitudinal slanting field also mediates a spin-1/f-charge noise interaction,
which causes the pure dephasing of the spin qubit. Choosing proper spectrum
function strength, we find the spin dephasing time is about $T^{*}_{2}=20$
$\mu$s and the spin echo time is about $T^{\rm echo}_{2}=100$ $\mu$s in a Si
quantum dot. We also propose several strategies to alleviate the spin
dephasing, such as lowering the experimental temperature, reducing the quantum
dot size, engineering the slanting field, or using the dynamical decoupling
scheme.",1804.05476v3
2020-09-10,Spin polarization recovery and Hanle effect for charge carriers interacting with nuclear spins in semiconductors,"We report on theoretical and experimental study of the spin polarization
recovery and Hanle effect for the charge carriers interacting with the
fluctuating nuclear spins in the semiconductor structures. We start the
theoretical description from the simplest model of static and isotropic nuclear
spin fluctuations. Then we describe the modification of the polarization
recovery and Hanle curves due to the anisotropy of the hyperfine interaction,
finite nuclear spin correlation time, and the strong pulsed spin excitation.
For the latter case, we describe the resonance spin amplification effect in the
Faraday geometry and discuss the manifestations of the quantum Zeno effect. The
set of the experimental results for various structures and experimental
conditions is chosen to highlight the specific effects predicted theoretically.
We show that the spin polarization recovery is a very valuable tool for
addressing carrier spin dynamics in semiconductors and their nanostructures.",2009.04805v1
2016-11-04,Hybrid continuous dynamical decoupling: a photon-phonon doubly dressed spin,"We study the parametric interaction between a single Nitrogen-Vacancy
electronic spin and a diamond mechanical resonator in which the spin is
embedded. Coupling between spin and oscillator is achieved by crystal strain,
which is generated upon actuation of the oscillator and which parametrically
modulates the spins' energy splitting. Under coherent microwave driving of the
spin, this parametric drive leads to a locking of the spin Rabi frequency to
the oscillator mode in the megahertz range. Both the Rabi oscillation decay
time and the inhomogeneous spin dephasing time increase by two orders of
magnitude under this spin-locking condition. We present routes to prolong the
dephasing times even further, potentially to the relaxation time limit. The
remarkable coherence protection that our hybrid spin-oscillator system offers
is reminiscent of recently proposed concatenated continuous dynamical
decoupling schemes and results from our robust, drift-free strain-coupling
mechanism and the narrow linewidth of the high-quality diamond mechanical
oscillator employed. Our findings suggest feasible applications in quantum
information processing and sensing.",1611.01515v1
2016-11-22,Control and Local Measurement of the Spin Chemical Potential in a Magnetic Insulator,"The spin chemical potential characterizes the tendency of spins to diffuse.
Probing the spin chemical potential could provide insight into materials such
as magnetic insulators and spin liquids and aid optimization of spintronic
devices. Here, we introduce single-spin magnetometry as a generic platform for
non-perturbative, nanoscale characterization of spin chemical potentials. We
use this platform to investigate magnons in a magnetic insulator, surprisingly
finding that the magnon chemical potential can be efficiently controlled by
driving the system's ferromagnetic resonance. We introduce a symmetry-based
two-fluid theory describing the underlying magnon processes, realize the first
experimental determination of the local thermomagnonic torque, and illustrate
the detection sensitivity using electrically controlled spin injection. Our
results open the way for nanoscale control and imaging of spin transport in
mesoscopic spin systems.",1611.07408v1
2019-01-17,Spin transport parameters of NbN thin films characterised by spin pumping experiments,"We present measurements of ferromagnetic-resonance - driven spin pumping and
inverse spin-Hall effect in NbN/Y3Fe5O12 (YIG) bilayers. A clear enhancement of
the (effective) Gilbert damping constant of the thin-film YIG was observed due
to the presence of the NbN spin sink. By varying the NbN thickness and
employing spin-diffusion theory, we have estimated the room temperature values
of the spin diffusion length and the spin Hall angle in NbN to be 14 nm and
-1.1 10-2, respectively. Furthermore, we have determined the spin-mixing
conductance of the NbN/YIG interface to be 10 nm-2. The experimental
quantification of these spin transport parameters is an important step towards
the development of superconducting spintronic devices involving NbN thin films.",1901.05753v1
2020-05-18,Spin squeezing in a spin-orbit coupled Bose-Einstein condensate,"We study the spin squeezing in a spin-1/2 Bose-Einstein condensates (BEC)
with Raman induced spin-orbit coupling (SOC). Under the condition of two-photon
resonance and weak Raman coupling strength, the system possesses two degenerate
ground states, using which we construct an effective two-mode model. The
Hamiltonian of the two-mode model takes the form of the one-axis-twisting
Hamiltonian which is known to generate spin squeezing. More importantly, we
show that the SOC provides a convenient control knob to adjust the spin
nonlinearity responsible for spin squeezing. Specifically, the spin
nonlinearity strength can be tuned to be comparable to the two-body
density-density interaction, hence is much larger than the intrinsic
spin-dependent interaction strength in conventional two-component BEC systems
such as $^{87}$Rb and $^{23}$Na in the absence of the SOC. We confirm the spin
squeezing by carrying out a fully beyond-mean-field numerical calculation using
the truncated Wigner method. Additionally, the experimental implementation is
also discussed.",2005.08532v2
2020-07-20,Sizable spin-transfer torque in Bi/Ni80Fe20 bilayer film,"The search for efficient spin conversion in Bi has attracted great attention
in spin-orbitronics. In the present work, we employ spin-torque ferromagnetic
resonance to investigate spin conversion in Bi/Ni80Fe20(Py) bilayer films with
continuously varying Bi thickness. In contrast with previous studies, sizable
spin-transfer torque (i.e., a sizable spin-conversion effect) is observed in
Bi/Py bilayer film. Considering the absence of spin conversion in
Bi/yttrium-iron-garnet bilayers and the enhancement of spin conversion in
Bi-doped Cu, the present results indicate the importance of material
combinations to generate substantial spin-conversion effects in Bi.",2007.09830v1
2022-07-30,Spin transport properties in a naphthyl diamine derivative film investigated by the spin pumping,"We report the spin transport properties in a thin film of a naphthyl diamine
derivative: N,N'-Bis(naphthalen-1-yl)-N,N'-bis(phenyl)-2,2'-dimethylbenzidine
(alpha-NPD). In a palladium(Pd)/alpha-NPD/Ni80Fe20 tri-layer structure sample,
a pure spin current is generated in the alpha-NPD layer with the spin pumping
driven by ferromagnetic resonance (FMR). The generated spin current is absorbed
into the Pd layer, and converted into a charge current with the inverse
spin-Hall effect (ISHE) in Pd. An electromotive force due to the ISHE in the Pd
layer is observed under the FMR of the Ni80Fe20 layer, which is clear evidence
for the spin transport in an alpha-NPD film. The spin diffusion length in an
alpha-NPD film is estimated to be about 62 nm at room temperature, which is
long enough as a spin transport material for spintronic devices.",2208.00170v3
2023-07-13,Mapping a 50-spin-qubit network through correlated sensing,"Spins associated to optically accessible solid-state defects have emerged as
a versatile platform for exploring quantum simulation, quantum sensing and
quantum communication. Pioneering experiments have shown the sensing, imaging,
and control of multiple nuclear spins surrounding a single electron-spin
defect. However, the accessible size and complexity of these spin networks has
been constrained by the spectral resolution of current methods. Here, we map a
network of 50 coupled spins through high-resolution correlated sensing schemes,
using a single nitrogen-vacancy center in diamond. We develop concatenated
double-resonance sequences that identify spin-chains through the network. These
chains reveal the characteristic spin frequencies and their interconnections
with high spectral resolution, and can be fused together to map out the
network. Our results provide new opportunities for quantum simulations by
increasing the number of available spin qubits. Additionally, our methods might
find applications in nano-scale imaging of complex spin systems external to the
host crystal.",2307.06939v1
2023-08-02,Muon spin force,"Current discrepancy between the measurement and the prediction of the muon
anomalous magnetic moment can be resolved in the presence of a long-range force
created by ordinary atoms acting on the muon spin via axial-vector and/or
pseudoscalar coupling, and requiring a tiny, $\mathcal{O}(10^{-13}\,{\rm eV})$
spin energy splitting between muon state polarized in the vertical direction.
We suggest that an extension of the muon spin resonance ($\mu$SR) experiments
can provide a definitive test of this class of models. We also derive indirect
constraints on the strength of the muon spin force, by considering the
muon-loop-induced interactions between nuclear spin and external directions.
The limits on the muon spin force extracted from the comparison of
$^{199}$Hg/$^{201}$Hg and $^{129}$Xe/$^{131}$Xe spin precession are strong for
the pseudoscalar coupling, but are significantly relaxed for the axial-vector
one. These limits suffer from significant model uncertainties, poorly known
proton/neutron spin content of these nuclei, and therefore do not exclude the
possibility of a muon spin force relevant for the muon $g-2$.",2308.01356v1
2013-02-28,Number and spin densities in the ground state of a trapped mixture of two pseudospin-1/2 Bose gases with interspecies spin-exchange interaction,"We consider the ground state of a mixture of two pseudospin-$\1/2$ Bose gases
with interspecies spin exchange in a trapping potential. In the mean field
approach, the ground state can be described in terms of four wave functions
governed by a set of coupled Gross-Pitaevskii-like (GP-like) equations, which
differ from the usual GP equations in the existence of an interference term due
to spin-exchange coupling between the two species. Using these GP-like
equations, we calculate such ground state properties as chemical potentials,
density profiles and spin density profiles, which are directly observable in
experiments. We compare the cases with and without spin exchange. It is
demonstrated that the spin exchange between the two species lowers the chemical
potentials, tends to equalize the wave functions of the two pseudospin
components of each species, and thus homogenizes the spin density. The novel
features of the density and spin density profiles can serve as experimental
probes of this novel Bose system.",1302.7217v1
2016-07-27,"Initial data for black hole-neutron star binaries, with rotating stars","The coalescence of a neutron star with a black hole is a primary science
target of ground-based gravitational wave detectors. Constraining or measuring
the neutron star spin directly from gravitational wave observations requires
knowledge of the dependence of the emission properties of these systems on the
neutron star spin. This paper lays foundations for this task, by developing a
numerical method to construct initial data for black hole--neutron star
binaries with arbitrary spin on the neutron star. We demonstrate the robustness
of the code by constructing initial-data sets in large regions of the parameter
space. In addition to varying the neutron star spin-magnitude and
spin-direction, we also explore neutron star compactness, mass-ratio, black
hole spin, and black hole spin-direction. Specifically, we are able to
construct initial data sets with neutron stars spinning near centrifugal
break-up, and with black hole spins as large as $S_{\rm BH}/M_{\rm BH}^2=0.99$.",1607.07962v1
2017-12-03,Two-spinor description of massive particles and relativistic spin projection operators,"On the basis of the Wigner unitary representations of the covering group
ISL(2,C) of the Poincar\'{e} group, we obtain spin-tensor wave functions of
free massive particles with arbitrary spin. The wave functions automatically
satisfy the Dirac-Pauli-Fierz equations. In the framework of the two-spinor
formalism we construct spin-vectors of polarizations and obtain conditions that
fix the corresponding relativistic spin projection operators (Behrends-Fronsdal
projection operators). With the help of these conditions we find explicit
expressions for relativistic spin projection operators for integer spins
(Behrends-Fronsdal projection operators) and then find relativistic spin
projection operators for half integer spins. These projection operators
determine the nominators in the propagators of fields of relativistic
particles. We deduce generalizations of the Behrends-Fronsdal projection
operators for arbitrary space-time dimensions D>2.",1712.00833v2
2019-11-11,Theory and phase-field simulations on electrical control of spin cycloids in a multiferroic,"Cycloidal spin orders are common in multiferroics. One of the prototypical
examples is BiFeO3 (BFO) which shows a large polarization and a cycloidal
antiferromagnetic order at room temperature. Here we employ Landau theory and
phase-field simulations to analyze the coupled switching dynamics of
polarization and cycloidal antiferromagnetic orders in BFO. We are able to
identify 14 types of transitional spin structures between two cycloids and 9
electric-field-induced spin switching paths. We demonstrate the
electric-field-induced rotation of wave vectors of the cycloidal spins and
discover 2 types of cycloidal spin switching dynamics: fast local spin flips
and slow rotation of wave vectors. Also, we construct road maps to achieve the
switching between any two spin cycloids through multi-step applications of
electric fields. The work provides a theoretical framework for the
phenomenological description of spin cycloids and a fundamental understanding
of the switching mechanisms to achieve electrical control of magnetic orders.",1911.04023v2
2017-10-12,Quasiclassical theory of spin dynamics in superfluid $^3$He: kinetic equations in the bulk and spin response of surface Majorana states,"We develop a theory based on the formalism of quasiclassical Green's
functions to study the spin dynamics in superfluid $^3$He. First, we derive
kinetic equations for the spin-dependent distribution function in the bulk
superfluid reproducing the results obtained earlier without quasiclassical
approximation. Then we consider a spin dynamics near the surface of fully
gapped $^3$He-B phase taking into account spin relaxation due to the
transitions in the spectrum of localized fermionic states. The lifetime of
longitudinal and transverse spin waves is calculate taking into account the
Fermi-liquid corrections which lead to the crucial modification of fermionic
spectrum and spin responses.",1710.04468v2
2018-04-25,"Spinning Mellin Bootstrap: Conformal Partial Waves, Crossing Kernels and Applications","We study conformal partial waves (CPWs) in Mellin space with totally
symmetric external operators of arbitrary integer spin. The exchanged spin is
arbitrary, and includes mixed symmetry and (partially)-conserved
representations. In a basis of CPWs recently introduced in arXiv:1702.08619, we
find a remarkable factorisation of the external spin dependence in their Mellin
representation. This property allows a relatively straightforward study of
inversion formulae to extract OPE data from the Mellin representation of
spinning 4pt correlators and in particular, to extract closed-form expressions
for crossing kernels of spinning CPWs in terms of the hypergeometric function
${}_4F_3$. We consider numerous examples involving both arbitrary internal and
external spins, and for both leading and sub-leading twist operators. As an
application, working in general $d$ we extract new results for ${\cal
O}\left(1/N\right)$ anomalous dimensions of double-trace operators induced by
double-trace deformations constructed from single-trace operators of generic
twist and integer spin. In particular, we extract the anomalous dimensions of
double-trace operators $[\mathcal{O}_J\Phi]_{n,l}$ with ${\cal O}_J$ a
single-trace operator of integer spin $J$.",1804.09334v2
2021-02-03,Spin-governed topological surfaces and broken spin-momentum locking in a gyromagnetic medium,"Topology of isofrequency surfaces plays a crucial role in characterizing the
interaction of an electromagnetic wave with a medium. Thus, engineering the
topology in complex media is leading to novel applications, ranging from
super-resolution microscopy with hyperbolic metamaterials to sub-wavelength
waveguiding structures. Here, we investigate the spin-governed nature of
isofrequency surfaces in a general gyromagnetic medium. We show that gyrotropy
also plays an important role in the topological properties of a medium, along
with the anisotropic permeability and permittivity. Even though the topology
primarily depends on permeability, gyrotropy can suppress or support the
existence of certain topological surfaces. We reveal the connection between the
gyrotropy imposed constraints and the photonic spin-profile of the topological
surfaces. The spin-profile along the isofrequency surface is locked to the
material, resulting in the non-reciprocity and breaking of the spin-momentum
locking in the gyromagnetic medium. Further, we show that the conflict between
spin-momentum locking and material locked spin leads to asymmetric mode profile
and gyrotropy-induced cutoff in guided wave structures. Our work provides
important insights into the underlying link between topology, spin, and
non-reciprocity in gyrotropic media.",2102.02027v1
2019-01-21,"Magnonics: Spin Waves Connecting Charges, Spins and Photons","Spin waves (SW) are the excitation of the spin system in a ferromagnetic
condensed matter body. They are collective excitations of the electron system
and, from a quasi-classical point of view, can be understood as a coherent
precession of the electrons' spins. Analogous to photons, they are also
referred to as magnons indicating their quasi-particle character. The
collective nature of SWs is established by the short-range exchange interaction
as well as the non-local magnetic dipolar interaction, resulting in coherence
of SWs from mesoscopic to even macroscopic length scales. As one consequence of
this collective interaction, SWs are ""charge current free"" and, therefore, less
subject to dissipation caused by scattering with impurities on the atomic
level. This is a clear advantage over diffusive transport in spintronics that
not only uses the charge of an electron but also its spin degree of freedom.
Any (spin) current naturally involves motion and, thus, scattering of electrons
leading to excessive heating as well as losses. This renders SWs a promising
alternative to electric (spin) currents for the transport of spin information -
one of the grand challenges of condensed matter physics.",1901.07021v1
2019-07-02,Spin-orbit interaction and snake states in graphene $p$-$n$ junctions,"We study a model of a $p$-$n$ junction in single-layer graphene in the
presence of a perpendicular magnetic field and spin-orbit interactions. By
solving the relevant quantum-mechanical problem for a potential step, we
determine the exact spectrum of spin-resolved dispersive Landau levels. Close
to zero energy, we find a pair of linearly dispersing zero modes, which possess
a wave-vector-dependent spin polarization and can be regarded as quantum
analogous of spinful snake states. We show that the Rashba spin-orbit
interaction, in particular, produces a wave vector shift between the
dispersions of these modes with observable interference effects. These effects
can in principle provide a way to detect the presence of Rashba spin-orbit
interaction and measure its strength. Our results suggest that a graphene
$p$-$n$ junction in the presence of strong spin-orbit interaction could be used
as a building block in a spin field-effect transistor.",1907.01233v2
2019-07-17,Transverse photon spin beyond interfaces,"Photons possess spin degree of freedom, corresponding to clockwise and
counter clockwise rotating direction of the fields. Photon spin plays an
important role in various applications such as optical communications,
information processing and sensing. In conventional isotropic media, photon
spin is aligned with the propagation direction of light, obeying spin momentum
locking. Interestingly, at certain interfaces, the surface waves decaying away
from the interface possess a photon spin transverse to its propagation, opening
exciting opportunities for observation of spin dependent unidirectional
excitation in confined systems. Here we propose and realize transverse photon
spin (T-spin) in the interior of a bulk medium, without relying on the presence
of any interfaces. We show the complete mapping of the T-spin of surface modes
to that of the bulk modes by introducing the coupling between electric and
magnetic responses along orthogonal directions, i.e., the bianisotropy, into
the medium. We further discover that an interface formed by two bianisotropic
media of opposite orientations supports edge-dependent propagating modes with
tunable cutoff frequencies. Our results provide a new platform for manipulating
the spin orbit interaction of electromagnetic waves.",1907.07654v1
2022-01-18,Spin generalizations of the Benjamin-Ono equation,"We present new soliton equations related to the $A$-type spin Calogero-Moser
(CM) systems introduced by Gibbons and Hermsen. These equations are spin
generalizations of the Benjamin-Ono (BO) equation and the recently introduced
non-chiral intermediate long-wave (ncILW) equation. We obtain multi-soliton
solutions of these spin generalizations of the BO equation and the ncILW
equation via a spin-pole ansatz where the spin-pole dynamics is governed by the
spin CM system in the rational and hyperbolic cases, respectively. We also
propose physics applications of the new equations, and we introduce a spin
generalization of the standard intermediate long-wave equation which
interpolates between the matrix Korteweg-de Vries equation, the Heisenberg
ferromagnet equation, and the spin BO equation.",2201.07269v1
2022-02-18,Intrinsic spin-momentum dynamics of surface electromagnetic waves in complex dispersive system,"Spin-momentum locking is an intrinsic property of surface electromagnetic
fields and its study has led to the discovery of photonic spin lattices and
diverse applications. Previously, dispersion was ignored in the spin-momentum
locking, giving rise to abnormal phenomena contradictory to the physical
realities. Here, we formulate four dispersive spin-momentum equations for
surface waves, revealing universally that the transverse spin vector is locked
with the momentum. The locking property obeys the right-hand rule in the
dielectric but the left-hand rule in the dispersive metal/magnetic materials.
In addition to the dispersion, the structural features can affect the
spin-momentum locking significantly. Remarkably, an extraordinary longitudinal
spin originating from the coupling polarization ellipticity is uncovered even
for the purely polarized state. We further demonstrate the spin-momentum
locking properties with diverse photonic topological lattices by engineering
the rotating symmetry. The findings open up opportunities for designing robust
nanodevices with practical importance in chiral quantum optics.",2202.09007v1
2022-03-26,Spin and Contextuality in Extended de Broglie-Bohm-Bell Quantum Mechanics,"This paper introduces an extension of the de Broglie-Bohm-Bell formulation of
quantum mechanics, which includes intrinsic particle degrees of freedom, such
as spin, as elements of reality. To evade constraints from the Kochen-Specker
theorem the discrete spin values refer to a specific basis -- i.e., a single
spin vector orientation for each particle; these spin orientations are,
however, not predetermined, but dynamic and guided by the (reduced, spin-only)
wave function of the system, which is conditional on the realized location
values of the particles. In this way, the unavoidable contextuality of spin is
provided by the wave function and its realized particle configuration, whereas
spin is still expressed as a local property of the individual particles. This
formulation, which furthermore features a rigorous discrete-time stochastic
dynamics, allows for numerical simulations of particle systems with entangled
spin, such as Bohm's version of the EPR experiment.",2203.14034v1
2023-02-20,Néel-Vector Switching and THz Spin-Wave Excitation in Mn$_2$Au due to Femtosecond Spin-Transfer Torques,"Efficient and fast manipulation of antiferromagnets has to date remained a
challenging task, hindering their application in spintronic devices. For
ultrafast operation of such devices, it is highly desirable to be able to
control the antiferromagnetic order within picoseconds - a timescale that is
difficult to achieve with electrical circuits. Here, we demonstrate that bursts
of spin-polarized hot-electron currents emerging due to laser-induced ultrafast
demagnetization are able to efficiently excite spin dynamics in
antiferromagnetic Mn$_2$Au by exerting a spin-transfer torque on femtosecond
timescales. We combine quantitative superdiffusive transport and atomistic
spin-model calculations to describe a spin-valve-type trilayer consisting of
Fe$|$Cu$|$Mn$_2$Au. Our results demonstrate that femtosecond spin-transfer
torques can switch the Mn$_2$Au layer within a few picoseconds. In addition, we
find that spin waves with high frequencies up to several THz can be excited in
Mn$_2$Au.",2302.09822v1
2023-03-29,Asymptotic gravitational-wave fluxes from a spinning test body on generic orbits around a Kerr black hole,"This work provides gravitational wave energy and angular momentum asymptotic
fluxes from a spinning body moving on generic orbits in a Kerr spacetime up to
linear in spin approximation. To achieve this, we have developed a new
frequency domain Teukolsky equation solver that calculates asymptotic
amplitudes from generic orbits of spinning bodies with their spin aligned with
the total orbital angular momentum. However, the energy and angular momentum
fluxes from these orbits in the linear in spin approximation are appropriate
for adiabatic models of extreme mass ratio inspirals even for spins non-aligned
to the orbital angular momentum. To check the newly obtained fluxes, they were
compared with already known frequency domain results for equatorial orbits and
with results from a time domain Teukolsky equation solver called Teukode for
off-equatorial orbits. The spinning body framework of our work is based on the
Mathisson-Papapetrou-Dixon equations under the Tulczyjew-Dixon spin
supplementary condition.",2303.16798v1
2023-08-30,Spin Rotations in a Bose-Einstein Condensate Driven by Counterflow and Spin-independent Interactions,"We observe spin rotations caused by atomic collisions in a non-equilibrium
Bose-condensed gas of $^{87}$Rb. Reflection from a pseudomagnetic barrier
creates counterflow in which forward- and backward-propagating matter waves
have partly transverse spin directions. Even though inter-atomic interaction
strengths are state-independent, the indistinguishability of parallel spins
leads to spin dynamics. A local magnetodynamic model, which captures the
salient features of the observed spin textures, highlights an essential
connection between four-wave mixing and collisional spin rotation. The observed
phenomenon has previously been thought to exist only in nondegenerate gases;
our observations and model clarify the nature of these effective-magnetic spin
rotations.",2308.16069v1
2018-01-15,Coupling Two Spin Qubits with a High-Impedance Resonator,"Fast, high-fidelity single and two-qubit gates are essential to building a
viable quantum information processor, but achieving both in the same system has
proved challenging for spin qubits. We propose and analyze an approach to
perform a long-distance two-qubit controlled phase (CPHASE) gate between two
singlet-triplet qubits using an electromagnetic resonator to mediate their
interaction. The qubits couple longitudinally to the resonator, and by driving
the qubits near the resonator's frequency they can be made to acquire a
state-dependent geometric phase that leads to a CPHASE gate independent of the
initial state of the resonator. Using high impedance resonators enables gate
times of order 10 ns while maintaining long coherence times. Simulations show
average gate fidelities of over 96% using currently achievable experimental
parameters and over 99% using state-of-the-art resonator technology. After
optimizing the gate fidelity in terms of parameters tuneable in-situ, we find
it takes a simple power-law form in terms of the resonator's impedance and
quality and the qubits' noise bath.",1801.04858v4
2016-03-12,Magnetic Resonance Force Detection using a Membrane Resonator,"The availability of compact, low-cost magnetic resonance imaging instruments
would further broaden the substantial impact of this technology. We report
highly sensitive detection of magnetic resonance using low-stress silicon
nitride (SiN$_x$) membranes. We use these membranes as low-loss, high-frequency
mechanical oscillators and find they are able to mechanically detect
spin-dependent forces with high sensitivity enabling ultrasensitive magnetic
resonance detection. The high force detection sensitivity stems from their high
mechanical quality factor $Q\sim10^6$ combined with the low mass of the
resonator. We use this excellent mechanical force sensitivity to detect the
electron spin magnetic resonance using a SiN$_x$ membrane as a force detector.
The demonstrated force sensitivity at 300 K is 4 fN/$\sqrt{\mathrm{Hz}}$,
indicating a potential low temperature (4 K) sensitivity of 25
aN/$\sqrt{\mathrm{Hz}}$. Given their sensitivity, robust construction, large
surface area and low cost, SiN$_x$ membranes can potentially serve as the
central component of a compact room-temperature ESR and NMR instrument that has
superior spatial resolution to conventional approaches.",1603.03953v2
2016-03-24,The theory of secondary resonances in the spin-orbit problem,"We study the resonant dynamics in a simple one degree of freedom, time
dependent Hamiltonian model describing spin-orbit interactions. The equations
of motion admit periodic solutions associated with resonant motions, the most
important being the synchronous one in which most evolved satellites of the
Solar system, including the Moon, are observed. Such primary resonances can be
surrounded by a chain of smaller islands which one refers to as secondary
resonances. Here, we propose a novel canonical normalization procedure allowing
to obtain a higher order normal form, by which we obtain analytical results on
the stability of the primary resonances as well as on the bifurcation
thresholds of the secondary resonances. The procedure makes use of the
expansion in a parameter, called the detuning, measuring the shift from the
exact secondary resonance. Also, we implement the so-called `book-keeping'
method, i.e., the introduction of a suitable separation of the terms in orders
of smallness in the normal form construction, which deals simultaneously with
all the small parameters of the problem. Our analytical computation of the
bifurcation curves is in excellent agreement with the results obtained by a
numerical integration of the equations of motion, thus providing relevant
information on the parameter regions where satellites can be found in a stable
configuration.",1603.07760v1
2018-07-11,Probing the Dzyaloshinskii-Moriya interaction via the propagation of spin waves in ferromagnetic thin films,"The Dzyaloshinskii-Moriya interaction (DMI) has attracted considerable recent
attention owing to the intriguing physics behind and the fundamental role it
played in stabilizing magnetic solitons, such as magnetic skyrmions and chiral
domain walls. A number of experimental efforts have been devoted to probe the
DMI, among which the most popular method is the Brillouin light scattering
spectroscopy (BLS) to measure the frequency difference of spin waves with
opposite wave vectors $\pm\mathbf{k}$ perpendicular to the in-plane
magnetization $\mathbf{m}$. Such a technique, however, is not applicable for
the cases of $\mathbf{k}\parallel\mathbf{m}$, since the spin-wave reciprocity
is recovered then. For a narrow magnetic strip, it is also difficult to measure
the DMI strength using BLS because of the spatial resolution limit of lights.
To fill these gaps, we propose to probe the DMI via the propagation of spin
waves in ferromagnetic films. We show that the DMI can cause the
non-collinearity of the group velocities of spin waves with
$\pm\mathbf{k}\parallel\mathbf{m}$. In heterogeneous magnetic thin films with
different DMIs, negative refractions of spin waves emerge at the interface
under proper conditions. These findings enable us to quantify the DMI strength
by measuring the angle between the two spin-wave beams with
$\pm\mathbf{k}\parallel\mathbf{m}$ in homogeneous film and by measuring the
incident and negative refraction angles in heterogeneous films. For a narrow
magnetic strip, we propose a nonlocal scheme to determine the DMI strength via
nonlinear three-magnon processes. We implement theoretical calculations and
micromagnetic simulations to verify our ideas. The results presented here are
helpful for future measurement of the DMI and for designing novel spin-wave
spintronic devices.",1807.04025v2
2008-09-24,The role of magnetic anisotropy in the Kondo effect,"In the Kondo effect, a localized magnetic moment is screened by forming a
correlated electron system with the surrounding conduction electrons of a
non-magnetic host. Spin S=1/2 Kondo systems have been investigated extensively
in theory and experiments, but magnetic atoms often have a larger spin. Larger
spins are subject to the influence of magnetocrystalline anisotropy, which
describes the dependence of the magnetic moment's energy on the orientation of
the spin relative to its surrounding atomic environment. Here we demonstrate
the decisive role of magnetic anisotropy in the physics of Kondo screening. A
scanning tunnelling microscope is used to simultaneously determine the
magnitude of the spin, the magnetic anisotropy and the Kondo properties of
individual magnetic atoms on a surface. We find that a Kondo resonance emerges
for large-spin atoms only when the magnetic anisotropy creates degenerate
ground-state levels that are connected by the spin flip of a screening
electron. The magnetic anisotropy also determines how the Kondo resonance
evolves in a magnetic field: the resonance peak splits at rates that are
strongly direction dependent. These rates are well described by the energies of
the underlying unscreened spin states.",0809.4289v1
2011-10-22,Theory of electronic properties and quantum spin blockade in a gated linear triple quantum dot with one electron spin each,"We present a theory of electronic properties and the spin blockade phenomena
in a gated linear triple quantum dot. Quadruple points where four different
charge configurations are on resonance, particularly involving (1,1,1)
configuration, are considered. In the symmetric case, the central dot is biased
to higher energy and a single electron tunnels through the device when (1,1,1)
configuration is resonant with (1,0,1),(2,0,1),(1,0,2) configurations. The
electronic properties of a triple quantum dot are described by a Hubbard model
containing two orbitals in the two unbiased dots and a single orbital in the
biased dot. The transport through the triple quantum dot molecule involves both
singly and doubly occupied configurations and necessitates the description of
the (1,1,1) configuration beyond the Heisenberg model. Exact eigenstates of the
triple quantum dot molecule with up to three electrons are used to compute
current assuming weak coupling to the leads and non-equilibrium occupation of
quantum molecule states obtained from the rate equation. The intra-molecular
relaxation processes due to acoustic phonons and cotunneling with the leads are
included, and are shown to play a crucial role in the spin blockade effect. We
find a quantum interference-based spin blockade phenomenon at low source-drain
bias and a distinct spin blockade due to a trap state at higher bias. We also
show that, for an asymmetric quadruple point with
(0,1,1),(1,1,1,),(0,2,1),(0,1,2) configurations on resonance, the spin blockade
is analogous to the spin blockade in a double quantum dot.",1110.4982v1
2013-11-02,Quantum-ring spin interference device tuned by quantum point contacts,"We introduce a spin-interference device that comprises a quantum ring (QR)
with three embedded quantum point contacts (QPCs) and study theoretically its
spin transport properties in the presence of Rashba spin-orbit interaction. Two
of the QPCs conform the lead-to-ring junctions while a third one is placed
symmetrically in the upper arm of the QR. Using an appropriate scattering model
for the QPCs and the $\mathbb{S}$-matrix scattering approach, we analyze the
role of the QPCs on the Aharonov-Bohm (AB) and Aharonov-Casher (AC) conductance
oscillations of the QR-device. Exact formulas are obtained for the
spin-resolved conductances of the QR-device as a function of the confinement of
the QPCs and the AB/AC phases. Conditions for the appearance of resonances and
anti-resonances in the spin-conductance are derived and discussed. We predict
very distinctive variations of the QR-conductance oscillations not seen in
previous QR proposals. In particular we find that the interference pattern in
the QR can be manipulated to a large extend by varying electrically the
lead-to-ring topological parameters. The latter can be used to modulate the AB
and AC phases by applying gate voltage only. We have shown also that the
conductance oscillations exhibits a crossover to well-defined resonances as the
lateral QPC confinement strength is increased, mapping the eigenenergies of the
QR. In addition, unique features of the conductance arises by varying the
aperture of the upper-arm QPC and the Rashba spin-orbit coupling. Our results
may be of relevance for promising spin-orbitonics devices based in quantum
interference mechanisms.",1311.0406v1
2014-10-23,Pulsed Low-Field Electrically Detected Magnetic Resonance,"We present pulsed electrically detected magnetic resonance (EDMR)
measurements at low magnetic fields using posphorus-doped silicon with natural
isotope composition as a model system. Our measurements show that pulsed EDMR
experiments, well established at X-band frequencies (10 GHz), such as coherent
spin rotations, Hahn echoes, and measurements of parallel and antiparallel spin
pair life times are also feasible at frequencies in the MHz regime. We find
that the Rabi frequency of the coupled 31P electron-nuclear spin system scales
with the magnetic field as predicted by the spin Hamiltonian, while the
measured spin coherence and recombination times do not strongly depend on the
magnetic field in the region investigated. The usefulness of pulsed low-field
EDMR for measurements of small hyperfine interactions is demonstrated by
electron spin echo envelope modulation measurements of the Pb0 dangling-bond
state at the Si/SiO2 interface. A pronounced modulation with a frequency at the
free Larmor frequency of hydrogen nuclei was observed for radio frequencies
between 38 MHz and 400 MHz, attributed to the nuclear magnetic resonance of
hydrogen in an adsorbed layer of water This demonstrates the high sensitivity
of low-field EDMR also for spins not directly participating in the
spin-dependent transport investigated.",1410.6464v2
2015-04-09,Optical hyperpolarization of 13C nuclear spins in nanodiamond ensembles,"Here we propose and analyse in detail protocols that can achieve rapid
hyperpolarization of 13C nuclear spins in randomly oriented ensembles of
nanodiamonds at room temperature. Our protocols exploit a combination of
optical polarization of electron spins in nitrogen-vacancy centers and the
transfer of this polarization to 13C nuclei by means of microwave control to
overcome the severe challenges that are posed by the random orientation of the
nanodiamonds and their nitrogen-vacancy centers. Specifically, these random
orientations result in exceedingly large energy variations of the electron spin
levels that render the polarization and coherent control of the
nitrogen-vacancy center electron spins as well as the control of their coherent
interaction with the surrounding 13C nuclear spins highly inefficient. We
address these challenges by a combination of an off-resonant microwave double
resonance scheme in conjunction with a realization of the integrated solid
effect which, together with adiabatic rotations of external magnetic fields or
rotations of nanodiamonds, leads to a protocol that achieves high levels of
hyperpolarization of the entire nuclear-spin bath in a randomly oriented
ensemble of nanodiamonds even at room temperature. This hyperpolarization
together with the long nuclear spin polarization lifetimes in nanodiamonds and
the relatively high density of 13C nuclei has the potential to result in a
major signal enhancement in 13C nuclear magnetic resonance imaging and suggests
functionalized and hyperpolarized nanodiamonds as a unique probe for molecular
imaging both in vitro and in vivo.",1504.02368v1
2016-09-15,Generating resonating valence bond states through Dicke subradiance,"Dicke's original thought experiment with two spins coupled to a photon mode
has recently been experimentally realized. We propose extending this experiment
to N spins and show that it naturally gives rise to highly entangled states. In
particular, it gives rise to dark states which have resonating valence bond
(RVB) character. We first consider a system of N two level spins in a cavity
with only one spin in the excited state. This initial state is a linear
combination of a dark state and a bright state. We point out the dark state is
a coherent superposition of singlets with resonating valence bond character. We
show that the coupling to the photon mode takes the spin system into a mixed
state with an entangled density matrix. We next consider an initial state with
half of the spins in the excited state. We show that there is a non-zero
probability for this to collapse into a dark state with RVB character. In the
lossy cavity limit, if no photon is detected within several decay time periods,
we may deduce that the spin system has collapsed onto the dark RVB state. We
show that the probability for this scales as 2/N, making it possible to
generate RVB states of 20 spins or more.",1609.04853v2
2016-12-09,Optical and microwave control of germanium-vacancy center spins in diamond,"A solid-state system combining a stable spin degree of freedom with an
efficient optical interface is highly desirable as an element for integrated
quantum optical and quantum information systems. We demonstrate a bright color
center in diamond with excellent optical properties and controllable electronic
spin states. Specifically, we carry out detailed optical spectroscopy of a
Germanium Vacancy (GeV) color center demonstrating optical spectral stability.
Using an external magnetic field to lift the electronic spin degeneracy, we
explore the spin degree of freedom as a controllable qubit. Spin polarization
is achieved using optical pumping, and a spin relaxation time in excess of 20
$\mu$s is demonstrated. Optically detected magnetic resonance (ODMR) is
observed in the presence of a resonant microwave field. ODMR is used as a probe
to measure the Autler-Townes effect in a microwave-optical double resonance
experiment. Superposition spin states were prepared using coherent population
trapping, and a pure dephasing time of about 19 ns was observed. Prospects for
realizing coherent quantum registers based on optically controlled GeV centers
are discussed.",1612.02947v2
2019-01-03,Rapid high-fidelity gate-based spin read-out in silicon,"Silicon spin qubits form one of the leading platforms for quantum
computation. As with any qubit implementation, a crucial requirement is the
ability to measure individual quantum states rapidly and with high fidelity. As
the signal from a single electron spin is minute, different spin states are
converted to different charge states. Charge detection so far mostly relied on
external electrometers, which hinders scaling to two-dimensional spin qubit
arrays. As an alternative, gate-based dispersive read-out based on off-chip
lumped element resonators were introduced, but here integration times of 0.2 to
2 ms were required to achieve single-shot read-out. Here we connect an on-chip
superconducting resonant circuit to two of the gates that confine electrons in
a double quantum dot. Measurement of the power transmitted through a feedline
coupled to the resonator probes the charge susceptibility, distinguishing
whether or not an electron can oscillate between the dots in response to the
probe power. With this approach, we achieve a signal-to-noise ratio (SNR) of
about six within an integration time of only 1 $\mu$s. Using Pauli's exclusion
principle for spin-to-charge conversion, we demonstrate single-shot read-out of
a two-electron spin state with an average fidelity of $>$98% in 6 $\mu$s. This
result may form the basis of frequency multiplexed read-out in dense spin qubit
systems without external electrometers, therefore simplifying the system
architecture.",1901.00687v1
2022-04-22,Controlling magnetism with light in a zero orbital angular momentum antiferromagnet,"Antiferromagnetic materials feature intrinsic ultrafast spin dynamics, making
them ideal candidates for future magnonic devices operating at THz frequencies.
A major focus of current research is the investigation of optical methods for
the efficient generation of coherent magnons in antiferromagnetic insulators.
In magnetic lattices endowed with orbital angular momentum, spin-orbit coupling
enables spin dynamics through the resonant excitation of low-energy electric
dipoles such as phonons and orbital resonances which interact with spins.
However, in magnetic systems with zero orbital angular momentum, microscopic
pathways for the resonant and low-energy optical excitation of coherent spin
dynamics are lacking. Here, we consider experimentally the relative merits of
electronic and vibrational excitations for the optical control of zero orbital
angular momentum magnets, focusing on a limit case: the antiferromagnet
manganese thiophoshate (MnPS3), constituted by orbital singlet Mn2+ ions. We
study the correlation of spins with two types of excitations within its band
gap: a bound electron orbital excitation from the singlet orbital ground state
of Mn2+ into an orbital triplet state, which causes coherent spin precession,
and a vibrational excitation of the crystal field that causes thermal spin
disorder. Our findings cast orbital transitions as key targets for magnetic
control in insulators constituted by magnetic centers of zero orbital angular
momentum.",2204.10574v1
2019-09-24,Resonant absorption in expanding coronal magnetic flux tubes with uniform density,"Aims. We investigate the transfer of energy between a standing kink mode and
azimuthal Alfven waves within an expanding flux tube. We consider the process
of resonant absorption in a loop with a non-uniform Alfven frequency profile
but in the absence of a radial density gradient. Methods. Using the MHD code,
Lare3d, we model an oscillating magnetic flux tube that expands radially with
height. An initially straight loop structure with a magnetic field enhancement
is relaxed towards a force-free state before a standing kink mode is
introduced. Results. We demonstrate that the transverse gradient in Alfven
frequency required for the existence of resonant field lines can be associated
with the expansion of a high field-strength flux tube from concentrated flux
patches. This allows for the conversion of energy between wave modes even in
the absence of the density profile typically assumed in wave heating models. As
with standing modes in straight flux tubes, small scales are dominated by the
vorticity at the loop apex and by currents at the foot points. The azimuthal
wave exhibits the structure of the expanded flux tube and is therefore
associated with smaller length scales close to the foot points of the flux
tube. Conclusions. Resonant absorption can proceed throughout the corona, even
in the absence of dense loop structures. The flux tube and MHD waves considered
are difficult to observe and our model highlights how estimating hidden wave
power within the solar atmosphere can be problematic. We highlight that, for
standing modes, the global properties of field lines are important for resonant
absorption and coronal conditions at a single altitude will not fully determine
the nature of MHD resonances. We provide a new model in partial response to the
criticism that wave heating models cannot self-consistently generate or sustain
the density profile upon which they typically rely.",1909.10781v1
2002-07-12,The N* Program at Jefferson Lab - Status and Prospects,"I discuss recent results on the electroproduction and photoproduction of
mesons in the region of non-strange baryon resonances. Results on the
quadrupole transition from the ground state nucleon to the Delta(1232) show the
importance of pion cloud contributions to explain the observed quadrupole
transition multipoles. The excitation of the ""Roper"" resonance is being studied
in single pion production using unpolarized cross sections measurements and
beam spin asymmetries. New results on the S_{11}(1535) transition formfactor
give now a consistent picture over a large Q2 range. First results on
electroproduction of p pi^+ pi^- show intruiging resonance structure. which is
difficult to explain in an isobar model fit using known resonance properties,
and may hint at excitation of a ""missing"" resonance. Searches for resonances in
K^+Lambda also reveal resonance-like behavior. I briefly address a new avenue
of N* physics using exclusive deeply virtual Compton scattering, recently
measured for the first time at JLAB and at DESY.",0207149v2
2000-07-10,"Properties of Some Resonances of the 55Mn(p,g)56Fe Reaction in the Ep = 1.3 - 1.8 Mev Region","Radiative decay of 21 resonances in the 55Mn(p,g)56Fe reaction was studied in
the proton beam energy region Ep = 1.3 - 1.8 MeV. Branching of decay to many
low lying bound states up to excitation energy Ex ~ 8 MeV was measured. Exact
energy of all resonances has been established what pointed out that five of the
resonances are very close doublets. For all studied resonances were determined
their spin-parity charakteristics. Assignment of some resonances as isobaric
analogues of the states in the 56Mn nucleus was discused and short note about
energy systematics of isobaric analogue resonances was shown.",0007008v1
2013-06-19,Distinguishing Color-Octet and Color-Singlet Resonances at the Large Hadron Collider,"Di-jet resonance searches are simple, yet powerful and model-independent,
probes for discovering new particles at hadron colliders. Once such a resonance
has been discovered it is important to determine the mass, spin, couplings,
chiral behavior and color properties to determine the underlying theoretical
structure. We propose a new variable which, in the absence of decays of the
resonance into new non-standard states, distinguishes between color-octet and
color-singlet resonances. To keep our study widely applicable we study
phenomenological models of color-octet and color-singlet resonances in flavor
universal as well as flavor non-universal scenarios. We present our analysis
for a wide range of mass (2.5 - 6 TeV), couplings and flavor scenarios for the
LHC with center of mass energy of 14 TeV and varying integrated luminosities of
30, 100, 300 and 1000 ${\rm fb}^{-1}$. We find encouraging results to
distinguish color-octet and color-singlet resonances for different flavor
scenarios at the LHC.",1306.4715v1
2013-12-22,Observation of low-field Fano-Feshbach resonances in ultracold gases of dysprosium,"We report the observation of resonance-like loss in the trap population of
ultracold dysprosium as a function of magnetic field, which we attribute to
anisotropy-induced Fano-Feshbach resonances arising from Dy's large magnetic
dipole moment and nonzero electronic orbital angular momentum. We recorded
these resonances for four different isotopes, three bosonic and one fermionic,
over a field range of 0-6 G and show that the number of resonances changes
significantly as a function of temperature, even in the nK regime. Most of the
observed resonances are of very narrow width. The fermionic isotope, unlike its
bosonic counterparts, possesses nonzero nuclear spin and exhibits a much higher
density of resonances.",1312.6401v1
2014-02-13,Three-body model calculations of Nucleon-Delta and Delta-Delta dibaryon resonances,"Three-body hadronic models with separable pairwise interactions are
formulated and solved to calculate resonance masses and widths of L=0 N-Delta
and Delta-Delta dibaryons using relativistic kinematics. For N-Delta,
I(JP)=1(2+) and 2(1+) resonances slightly below threshold are found by solving
pi-N-N Faddeev equations. For Delta-Delta, several resonances below threshold
are found by solving pi-N-Delta Faddeev equations in which the N-Delta
interaction is dominated by the 1(2+) and 2(1+) resonating channels. The lowest
Delta-Delta dibaryon resonances found are for I(JP)=0(3+) and 3(0+), the former
agreeing well both in mass and in width with the relatively narrow D_{03}(2370)
resonance observed recently by the WASA-at-COSY Collaboration. Its spin-isospin
symmetric partner D_{30} is predicted with mass around 2.4 GeV and width about
80 MeV.",1402.3171v2
2014-08-07,Polaritonic Feshbach Resonance,"A Feshbach resonance occurs when the energy of two interacting free particles
comes to resonance with a molecular bound state. When approaching this
resonance, dramatic changes in the interaction strength between the particles
occur. Feshbach resonances have been an essential tool to control the atom
interactions, which can even be switched from repulsive to attractive [1-4].
Thanks to Feshbach resonances many effects in ultracold atomic gases could be
explored [5, 6]. Here we demonstrate a Feshbach resonance based on polariton
spinor interactions that characterize the fundamental interaction process in
polariton quantum systems. We show the clear enhancement of attractive
interactions and the prompt change to repulsive interaction by tuning the
energy of two polaritons with anti-parallel spins across the biexciton bound
state energy. A mean field two-channel model quantitatively reproduces the
experimental results. This observation paves the way for a new tool to tune the
polariton interactions and to move forward into quantum correlated polariton
physics.",1408.1499v2
2016-03-15,Entangling distant resonant exchange qubits via circuit quantum electrodynamics,"We investigate a hybrid quantum system consisting of spatially separated
resonant exchange qubits, defined in three-electron semiconductor triple
quantum dots, that are coupled via a superconducting transmission line
resonator. Drawing on methods from circuit quantum electrodynamics and
Hartmann-Hahn double resonance techniques, we analyze three specific approaches
for implementing resonator-mediated two-qubit entangling gates in both
dispersive and resonant regimes of interaction. We calculate entangling gate
fidelities as well as the rate of relaxation via phonons for resonant exchange
qubits in silicon triple dots and show that such an implementation is
particularly well-suited to achieving the strong coupling regime. Our approach
combines the favorable coherence properties of encoded spin qubits in silicon
with the rapid and robust long-range entanglement provided by circuit QED
systems.",1603.04829v1
2016-11-27,Real-time measurement of nanotube resonator fluctuations in an electron microscope,"Mechanical resonators based on low-dimensional materials provide a unique
platform for exploring a broad range of physical phenomena. The mechanical
vibrational states are indeed extremely sensitive to charges, spins, photons,
and adsorbed masses. However, the roadblock is often the readout of the
resonator, since the detection of the vibrational states becomes increasingly
difficult for smaller resonators. Here, we report an unprecedentedly sensitive
method to detect nanotube resonators with effective masses in the 10^-20 kg
range. We use the beam of an electron microscope to resolve the mechanical
fluctuations of a nanotube in real-time for the first time. We obtain full
access to the thermally-driven Brownian motion of the resonator, both in space
and time domains. Our results establish the viability of carbon nanotube
resonator technology at room temperature and pave the way towards the
observation of novel thermodynamics regimes and quantum effects in
nano-mechanics.",1611.08873v1
2021-05-16,A Tidal Origin for a 3-body Resonance in Kepler-221,"Over the course of the last two decades, traditional models of planet
formation have been repeatedly challenged by the emerging census of extrasolar
planets. Key among them is the orbital architecture problem: while standard
models of orbital migration predict resonant orbits for short-period objects,
most planets do not appear to lie in orbital resonances. Here we show that the
four-planet system Kepler-221, not previously recognized to have active orbital
resonances, has a three-body commensurability relation unique within the Kepler
sample. Using a suite of numerical experiments as well as a perturbative
analysis, we demonstrate that this system likely began as a resonant chain and
proceeded to undergo large-scale divergence away from resonance, under the
action of tidal dissipation. Our results further indicate that obliquity tides,
driven by a secular spin-orbit resonance and mutual inclination, are an
excellent candidate for driving this orbital divergence, and that the high
tidal luminosity may also explain the anomalous size of planet b, which lies
within the Fulton radius gap.",2105.07368v1
2015-01-30,The Astrophysics of Resonant Orbits in the Kerr Metric,"This paper gives a complete characterization of resonant orbits in a Kerr
spacetime. A resonant orbit is defined as a geodesic for which the longitudinal
and radial orbital frequencies are commensurate. Our analysis is based on
expressing the resonance condition in its most symmetric form using Carlson's
integrals. We provide a number of concise formulae for the dependence of
resonances on the system parameters. Resonant effects may be observable during
the in-spiral of a compact object into a super-massive black hole. When the
slowly evolving orbital frequencies pass through a series of low-order
resonances, rapid changes in the orbital parameters could produce measurable
phase shifts in the emitted gravitational radiation (GW). Resonant orbits may
also capture dust leading to electromagnetic emission. The KAM theorem
indicates that, low order resonant orbits demarcate the regions where the onset
of chaos could occur around a perturbed black-hole. We find that the 1/2 and
2/3 resonances occur at ~4 and 5.4 Schwarzschild radii (Rs) from the event
horizon. For compact object in-spirals around super-massive black holes, this
region lies within the sensitivity band of space-based GW detectors. For Sgr
A*, length scales of ~41 and 55 microarcseconds and timescales of 50 and 79 min
respectively should be associated with resonant effects, if Sgr A* is
non-spinning. Spin decreases these values by up to ~32% and ~28%. These
length-scales are potentially resolvable with VLBI measurements. We find that
all low-order resonances are localized to the strong field region r < 50 Rs.
This fact guarantees the validity of using approximations based on averaging to
model the frequency evolution of a test object in region 50 Rs <r <1000 Rs. The
systematic determination of the multipole moments of the central object by
observing the orbit of a pulsar, free of chaotic effects, is thus possible.",1501.07728v1
2015-06-17,Spin Casimir Effect in Non-collinear Quantum Antiferromagnets,"The Casimir effect is a general phenomenon in physics, which arises when the
vacuum fluctuation of an arbitrary field is modified by static or slowly
varying boundary. However, its spin version is rarely addressed, mainly due to
the fact that a macroscopic boundary in quantum spin systems is hard to define.
In this article, we explore the spin Casimir effect induced by the zero-point
fluctuation of spin waves in a general non-collinear ordered quantum
antiferromagnet. This spin Casimir effect results in a spin torque between
local spins and further causes various singular and divergent results in the
framework of spin-wave theory, which invalidate the standard $1/S$ expansion
procedure. To avoid this dilemma, we develop a self-consistent spin-wave
expansion approach, which preserves the spin-wave expansion away from
singularities and divergence. A detailed spin-wave analysis of the
antiferromagnetic spin-1/2 Heisenberg model on a spatially anisotropic
triangular lattice is undertaken within our approach. Our results indicate that
the spiral order is only stable in the region $0.5<\alpha<1.2$, where $\alpha$
is the ratio of the coupling constants. In addition, the instability in the
region $1.2<\alpha<2$ is owing to the spin Casimir effect instead of the
vanishing sublattice magnetization. And this extended spiral instable region
may host some quantum disordered phases besides the quantum order by disorder
induced Neel phase. Furthermore, our method provides an efficient and
convenient tool that can estimate the correct exchange parameters and outline
the quantum phase diagrams, which can be useful for experimental fitting
processes in frustrated quantum magnets.",1506.05211v2
2001-01-24,Effects of dipolar field in the spin dynamics of a Fermi liquid,"We study spin dynamics of a normal Fermi liquid taking into account the
demagnetizing field produced by the spin system itself. Linear solutions of the
spin dynamics equations in the form of standing spin waves in a finite volume
of liquid are found. At almost all known experimental conditions the influence
of demagnetizing field can be satisfactorily described by the first order of
perturbation theory. We carried out perturbational calculations for two
geometries of experimental cell -- spherical and finite-cylindrical. We
performed also exact numerical simulations of the spin wave spectra in a
spherical cell at an arbitrary strength of the demagnetizing field.
  The obtained results are applied in particular to conditions of recent
experiment (G.Vermeulen and A.Roni, Phys. Rev. Lett. 86, 248 (2001)) related to
the problem of zero temperature transverse relaxation in a polarized Fermi
liquid. We found that not taking into account demagnetizing field leads to
negligible errors in the measured relaxation time, thus supporting the
conclusion of the absence of zero temperature spin wave damping.",0101368v3
2005-07-22,Spin waves in a one-dimensional spinor Bose gas,"We study a one-dimensional (iso)spin 1/2 Bose gas with repulsive
delta-function interaction by the Bethe Ansatz method and discuss the
excitations above the polarized ground state. In addition to phonons the system
features spin waves with a quadratic dispersion. We compute analytically and
numerically the effective mass of the spin wave and show that the spin
transport is greatly suppressed in the strong coupling regime, where the
isospin-density (or ``spin-charge'') separation is maximal. Using a
hydrodynamic approach, we study spin excitations in a harmonically trapped
system and discuss prospects for future studies of two-component ultracold
atomic gases.",0507513v1
1996-02-19,Gravitational waves from a spinning particle in circular orbits around a rotating black hole,"Using the Teukolsky and Sasaki-Nakamura formalisms for the perterbations
around a Kerr black hole, we calculate the energy flux of gravitational waves
induced by a {\it spinning} particle of mass $\mu$ and spin $S$ moving in
circular orbits near the equatorial plain of a rotating black hole of mass $M
(\gg \mu)$ and spin $Ma$. The calculations are performed by using the recently
developed post-Newtonian expansion technique of the Teukolsky equation. To
evaluate the source terms of perturbations caused by a {\it spinning} particle,
we used the equations of motion of a spinning particle derived by Papapetrou
and the energy momentum tensor of a spinning particle derived by Dixon. We
present the post-Newtonian formula of the gravitational wave luminosity up to
the order $(v/c)^5$ beyond the quadrupole formula including the linear order of
particle spin. The results obtained in this paper will be an important
guideline to the post-Newtonian calculation of the inspiral of two spinning
compact objects.",9602038v1
1993-04-28,Semiclassical analysis of two- and three-spin antiferromagnets and anyons on a sphere,"We do a semiclassical analysis for two or three spins which are coupled
antiferromagnetically to each other. The semiclassical wave functions transform
correctly under permutations of the spins if one takes into account the
Wess-Zumino term present in the path integral for spins. The Wess-Zumino term
here is a total derivative which has no effect on the energy spectrum. The
semiclassical problem is related to that of anyons moving on a sphere with the
statistics parameter $\theta$ being $2 \pi S$ for two spins and $3 \pi S$ for
three spins. Finally, we present a novel way of deriving the semiclassical wave
functions from the spin wave functions.",9304151v1
2008-01-21,First principles study on the spin transfer torques,"An efficient first principles method was developed to calculate spin transfer
torques in layered system with noncollinear magnetization. The complete
scattering wave function is determined by matching the wave function in the
scattering region with the Bloch states in the leads. The spin transfer torques
are obtained with aid of the scattering wave function. We applied our method to
the ferromagnetic spin valve and found that the material (Co, Ni and Ni80Fe20)
dependence of the spin transfer torques could be well understood by the Fermi
surface. Ni has much longer spin injection penetration length than Co.
Interfacial disorder is also considered. It is found that the spin transfer
torques could be enhanced by the interfacial disorder in some system.",0801.3135v1
2008-08-04,Ballistic magneto-thermal transport in a Heisenberg spin chain at low temperatures,"We study ballistic thermal transport in Heisenberg spin chain with
nearest-neighbor ferromagnetic interactions at low temperatures. Explicit
expressions for transmission coefficients are derived for thermal transport in
a periodic spin chain of arbitrary junction length by a spin-wave model. Our
analytical results agree very well with the ones from nonequilibrium Green's
function method. Our study shows that the transmission coefficient oscillates
with the frequency of thermal wave. Moreover, the thermal transmission shows
strong dependence on the intrachain coupling, the length of the spin chain, and
the external magnetic field. The results demonstrate the possibility of
manipulating spin-wave propagation and magnetothermal conductance in the
spin-chain junction by adjusting the intrachain coupling and/or the external
magnetic field.",0808.0380v2
2009-03-13,"Spin-wave velocities, density of magnetic excitations, and NMR relaxation in ferro-pnictides","We perform an analysis of the experimentally known temperature dependence of
the staggered magnetization in the antiferromagnetic phase. This analysis
allows us to put an upper limit on the unknown value of the spin wave velocity
along the stripes of equal spin direction (spin stripes). The velocity is about
ten times smaller than the velocity perpendicular to the spin stripes. The
strongly anisotropic spin-wave dispersion implies a high density of low energy
magnetic excitations. We demonstrate that this high density strongly enhances
the $^{75}$As NMR spin-lattice relaxation via the Raman scattering of magnons.
We derive the polarization dependence of this relaxation channel and find very
good agreement with experimental data. The high density of low energy magnetic
excitations deduced from our phenomenological analysis supports the scenario
that ferro-pnictides are close to a quantum phase transition.",0903.2313v2
2009-03-27,Dynamical magnetoelectric effects induced by the Dzyaloshinskii-Moriya interaction in multiferroics,"We study the dynamical interplay between ferroelectricity and magnetism in a
multiferroic with a helical magnetic order. We show that the dynamical
exchange-striction induces a biquadratic interaction between the spins and
transverse phonons resulting in quantum fluctuations of the spontaneous
ferroelectric polarization $\mathbf{P}$ in the ferroelectric phase. The
hybridization between the spin wave and the fluctuation of the electric
polarization leads to low-lying transverse phonon modes. Those are
perpendicular to $\mathbf{P}$ and to the helical spins at small wave vector but
then turn parallel to $\mathbf{P}$ at a wave vector close to the magnetic
modulation vector. For helical magnetic structure, the spin chirality which
determines the direction of $\mathbf{P}$, also possesses a long-range order.
Due to the dynamical Dzyaloshiskii-Moriya interaction, the spin-chirality is
strongly coupled to the spin fluctuation which implies an on-site inversion of
the spin-chirality in the ordered spin-1/2 system and results in a finite
scattering intensity of polarized neutrons from a cycloidal helimagnet.",0903.4751v1
2009-04-16,Antiferromagnetism in the magnetoelectric effect single crystal LiMnPO$_4$,"Elastic and inelastic neutron scattering studies reveal details of the
antiferromagnetic tansition and intriguing spin-dynamics in the
magneto-electric effect single crystal LiMnPO$_4$. The elastic scattering
studies confirm the system is antiferromagnetic (AFM) below $T_N$=33.75 K with
local magnetic moments (Mn$^{2+}$; $S = 5/2$) that are aligned along the
crystallographic a-axis. The spin-wave dispersion curves propagating along the
three principal axes, determined by inelastic scattering, are adequately
modeled in the linear spin-wave framework assuming a spin-Hamiltonian that is
parameterized by inter- and in-plane nearest- and next-nearest-neighbor
interactions, and by easy-plane anisotropy. The temperature dependence of the
spin dynamics makes this an excellent model many-body spin system to address
the question of the relationship between spin-wave excitations and the order
parameter.",0904.2580v1
2009-06-19,Overhauser's spin-density wave in exact-exchange spin density functional theory,"The spin density wave (SDW) state of the uniform electron gas is investigated
in the exact exchange approximation of noncollinear spin density functional
theory (DFT). Unlike in Hartree-Fock theory, where the uniform paramagnetic
state of the electron gas is unstable against formation of the spin density
wave for all densities, in exact-exchange spin-DFT this instability occurs only
for densities lower than a critical value. It is also shown that, although in a
suitable density range it is possible to find a non-interacting SDW ground
state Slater determinant with energy lower than the corresponding paramagnetic
state, this Slater determinant is not a self-consistent solution of the
Optimized Effective Potential (OEP) integral equations of noncollinear
spin-DFT. A selfconsistent solution of the OEP equations which gives an even
lower energy can be found using an excited-state Slater determinant where only
orbitals with single-particle energies in the lower of two bands are occupied
while orbitals in the second band remain unoccupied even if their energies are
below the Fermi energy.",0906.3721v2
2010-08-31,"Spin-flip excitations, spin waves, and magneto-excitons in graphene Landau levels at integer filling factors","We study collective electronic excitations in graphene in the integer quantum
Hall regime, concentrating mainly on excitations with spin reversal such as
spin-flip and spin-wave excitations. We show that these excitations are
correctly accounted for in the time-dependent Hartree-Fock and strong magnetic
field approximations, in contrast to spin-conserving (magneto-exciton) modes
which involve a strong Landau-level mixing at non-zero wave vectors. The
collective excitations are discussed in view of prominent theorems, such as
Kohn's and Larmor's. Whereas the latter remains valid in graphene and yields
insight into the understanding of spin-dependent modes, Kohn's theorem does not
apply to relativistic electrons in graphene. We finally calculate the exchange
correction to the chemical potential in the weak magnetic field limit.",1008.5304v2
2013-02-18,Engineering spin waves in a high-spin ultracold Fermi gas,"We report on the detailed study of multi-component spin-waves in an s=3/2
Fermi gas where the high spin leads to novel tensorial degrees of freedom
compared to s = 1/2 systems. The excitations of a spin-nematic state are
investigated from the linear to the nonlinear regime, where the tensorial
character is particularly pronounced. By tuning the initial state we engineer
the tensorial spin-wave character, such that the magnitude and sign of the
counterflow spin-currents are effectively controlled. A comparison of our data
with numerical and analytical results shows excellent agreement.",1302.4323v3
2013-08-26,Spin turbulence with small spin magnitude in spin-1 spinor Bose-Einstein condensates,"We theoretically and numerically study spin turbulence (ST) with small spin
magnitude in spin-1 spinor Bose-Einstein condensates by using the spin-1 spinor
Gross-Pitaevskii (GP)equations. This kind of ST is realized in two cases: (i)
with antiferromagnetic interaction and (ii) with ferromagnetic interaction
under a static magnetic field. The ST with small spin magnitude can exhibit two
characteristic power laws in the spectrum of the spin-dependent interaction
energy: -1 and -7/3 power laws in the low- and high-wave-number regions,
respectively. These power laws are derived from a Kolmogorov-type dimensional
scaling analysis for the equations of motion of the spin vector and nematic
tensor. To confirm these power laws, we perform a numerical calculation of the
spin-1 spinor GP equations in a two-dimensional uniform system. In case (i),
the -7/3 power law appears in the high-wave-number region, but the spectrum in
the low-wave-number region deviates from the -1 power law. In contrast, both -1
and -7/3 power laws are found to clearly appear in case (ii).",1308.5504v1
2015-02-11,Quantum spin Hall effect of light,"Maxwell's equations, formulated 150 years ago, ultimately describe properties
of light, from classical electromagnetism to quantum and relativistic aspects.
The latter ones result in remarkable geometric and topological phenomena
related to the spin-1 massless nature of photons. By analyzing fundamental spin
properties of Maxwell waves, we show that free-space light exhibits an
intrinsic quantum spin Hall effect, i.e., surface modes with strong
spin-momentum locking. These modes are evanescent waves that form, e.g.,
surface plasmon-polaritons at vacuum-metal interfaces. Our findings illuminate
the unusual transverse spin in evanescent waves and explain recent experiments
demonstrating the transverse spin-direction locking in the excitation of
surface optical modes. This deepens our understanding of Maxwell's theory,
reveals analogies with topological insulators for electrons, and offers
applications for robust spin-directional optical interfaces.",1502.03319v3
2015-10-21,Reconfigurable spin wave band structure of artificial square spin ice,"Artificial square spin ices are structures composed of magnetic elements
arranged on a geometrically frustrated lattice and located on the sites of a
two-dimensional square lattice, such that there are four interacting magnetic
elements at each vertex. Using a semi-analytical approach, we show that square
spin ices exhibit a rich spin wave band structure that is tunable both by
external magnetic fields and the configuration of individual elements. Internal
degrees of freedom can give rise to equilibrium states with bent magnetization
at the edges leading to characteristic excitations; in the presence of
magnetostatic interactions these form separate bands analogous to impurity
bands in semiconductors. Full-scale micromagnetic simulations corroborate our
semi-analytical approach. Our results show that artificial square spin ices can
be viewed as reconfigurable and tunable magnonic crystals that can be used as
metamaterials for spin-wave-based applications at the nanoscale.",1510.06385v2
2016-04-18,Spin-transfer torques in antiferromagnets: efficiency and quantification method,"We formulate a theory of spin-transfer torques in antiferromagnets, which
covers the small to large limits of the exchange coupling energy relative to
the kinetic energy of the inter-sublattice electron dynamics. Our theory
suggests a natural definition of the efficiency of spin-transfer torques in
antiferromagnets in terms of well-defined material parameters, revealing that
the charge current couples predominantly to the antiferromagnetic order
parameter and the sublattice-canting moment in, respectively, the limits of
large and small exchange coupling. The effects can be quantified by analyzing
the antiferromagnetic spin-wave dispersions in the presence of charge current:
in the limit of large exchange coupling the spin-wave Doppler shift always
occurs, whereas, in the opposite limit, the only spin-wave modes to react to
the charge current are ones that carry a pronounced sublattice-canting moment.
The findings offer a framework for understanding and designing spin-transfer
torques in antiferromagnets belonging to different classes of sublattice
structures such as, e.g., bipartite and layered antiferromagnets.",1604.05277v2
2017-12-22,Gravitational waves from spinning binary black holes at the leading post-Newtonian orders at all orders in spin,"We determine the binding energy, the total gravitational wave energy flux,
and the gravitational wave modes for a binary of rapidly spinning black holes,
working in linearized gravity and at leading orders in the orbital velocity,
but to all orders in the black holes' spins. Though the spins are treated
nonperturbatively, surprisingly, the binding energy and the flux are given by
simple analytical expressions which are finite (respectively third- and
fifth-order) polynomials in the spins. Our final results are restricted to the
important case of quasi-circular orbits with the black holes' spins aligned
with the orbital angular momentum.",1712.08603v2
2017-02-03,Research Note: The Expected Spins of Gravitational Wave Sources With Isolated Field Binary Progenitors,"We explore the consequences of dynamical evolution of field binaries composed
of a primary black hole (BH) and a Wolf-Rayet (WR) star in the context of
gravitational wave (GW) source progenitors. We argue, from general
considerations, that the spin of the WR-descendent BH will be maximal in a
significant number of cases due to dynamical effects. In other cases, the spin
should reflect the natal spin of the primary BH which are currently
theoretically unconstrained. We argue that the three currently published LIGO
systems (GW150914, GW151226, LVT151012) suggest that this spin is small. The
resultant effective spin distribution of gravitational wave sources should thus
be bi-model if this classic GW progenitor channel is indeed dominant. While
this is consistent with the LIGO detections thus far, it is in contrast to the
three best-measured high-mass x-ray binary (HMXB) systems. A comparison of the
spin distribution of HMXBs and GW sources should ultimately reveal whether or
not these systems arise from similar astrophysical channels.",1702.00885v1
2020-06-15,Magnetic Droplet Solitons,"Magnetic droplet solitons are dynamical magnetic textures that form due to an
attractive interaction between spin waves in thin films with perpendicular
magnetic anisotropy. Spin currents and the spin torques associated with these
currents enable their formation as they provide a means to excite
non-equilibrium spin wave populations and compensate their decay. Recent years
have seen rapid advances in experiments that realize and study magnetic
droplets. Important advances include the first direct x-ray images of droplets,
determination of their threshold and sustaining currents, measurement of their
generation and annihilation time and evidence for drift instabilities, which
can limit their lifetime in spin-transfer nanocontacts. This article reviews
these studies and contrasts these solitons to other types of spin-current
excitations such as spin-wave bullets, and static magnetic textures, including
magnetic vortices and skyrmions. Magnetic droplet solitons can also serve as
current controlled microwave frequency oscillators with potential applications
in neuromorphic chips as nonlinear oscillators with memory.",2006.08808v2
2022-03-10,Mass$\unicode{x2013}$spin Re-Parameterization for Rapid Parameter Estimation of Inspiral Gravitational-Wave Signals,"Estimating the source parameters of gravitational waves from compact binary
coalescence(CBC) is a key analysis task in gravitational-wave astronomy. To
deal with the increasing detection rate of CBC signals, optimizing the
parameter estimation analysis is crucial. The analysis typically employs a
stochastic sampling technique such as Markov Chain Monte Carlo(MCMC), where the
source parameter space is explored and regions of high Bayesian posterior
probability density are found. One of the bottlenecks slowing down the analysis
is the non-trivial correlation between masses and spins of colliding objects,
which makes the exploration of mass$\unicode{x2013}$spin space extremely
inefficient. We introduce a new set of mass$\unicode{x2013}$spin sampling
parameters which makes the posterior distribution to be simple in the new
parameter space, regardless of the true values of the parameters. The new
parameter combinations are obtained as the principal components of the Fisher
matrix for the restricted 1.5 post-Newtonian waveform. Our re-parameterization
improves the efficiency of MCMC by a factor of $\sim10$ for binary neutron star
with narrow-spin prior ($|\vec{\chi}|<0.05$) and $\sim100$ with broad-spin
prior ($|\vec{\chi}|<0.99$), under the assumption that the binary has spins
aligned with its orbital angular momentum.",2203.05216v1
2014-11-06,Ising-nematic order in the bilinear-biquadratic model for the iron pnictides,"Motivated by the recent inelastic neutron scattering (INS) measurements in
the iron pnictides which show a strong anisotropy of spin excitations in
directions perpendicular and parallel to the ordering wave-vector even above
the magnetic transition temperature $T_N$, we study the frustrated Heisenberg
model with a biquadratic spin-spin exchange interaction. Using the Dyson-Maleev
(DM) representation, which proves appropriate for all temperature regimes, we
find that the spin-spin dynamical structure factors are in excellent agreement
with experiment, exhibiting breaking of the $C_4$ symmetry even into the
paramagnetic region $T_N<T<T_{\sigma}$ which we refer to as the Ising-nematic
phase. In addition to the Heisenberg spin interaction, we include the
biquadratic coupling $K (\mathbf{S}_i\cdot \mathbf{S}_j)^2$ and study its
effect on the dynamical temperature range $T_{\sigma}-T_N$ of the Ising-nematic
phase. We find that this range reduces dramatically when even small values of
the interlayer exchange $J_c$ and biquadratic coupling $K$ are included. To
supplement our analysis, we benchmark the results obtained using the DM method
against those from different non-linear spin-wave theories, including the
recently developed generalized spin-wave theory (GSWT), and find good
qualitative agreement among the different theoretical approaches as well as
experiment for both the spin-wave dispersions and the dynamical structure
factors.",1411.1462v2
2015-08-30,Spin-transfer torque based damping control of parametrically excited spin waves in a magnetic insulator,"The damping of spin waves parametrically excited in the magnetic insulator
Yttrium Iron Garnet (YIG) is controlled by a dc current passed through an
adjacent normal-metal film. The experiment is performed on a macroscopically
sized YIG(100nm)/Pt(10nm) bilayer of 4x2 mm^2 lateral dimensions. The spin-wave
relaxation frequency is determined via the threshold of the parametric
instability measured by Brillouin light scattering (BLS) spectroscopy. The
application of a dc current to the Pt film leads to the formation of a
spin-polarized electron current normal to the film plane due to the spin Hall
effect (SHE). This spin current exerts a spin transfer torque (STT) in the YIG
film and, thus, changes the spin-wave damping. Depending on the polarity of the
applied dc current with respect to the magnetization direction, the damping can
be increased or decreased. The magnitude of its variation is proportional to
the applied current. A variation in the relaxation frequency of +/-7.5% is
achieved for an applied dc current density of 5*10^10 A/m^2.",1508.07517v1
2017-12-03,Stochastic gravitational-wave background from spin loss of black holes,"Although spinning black holes are shown to be stable in vacuum in general
relativity, there exists exotic mechanisms that can convert the spin energy of
black holes into gravitational waves. Such waves may be very weak in amplitude,
since the spin-down could take a long time, and a direct search may not be
feasible. We propose to search for the stochastic background associated with
the spin-down, and we relate the level of this background to the formation rate
of spinning black holes from the merger of binary black holes, as well as the
energy spectrum of waves emitted by the spin-down process. We argue that
current LIGO-Virgo observations are not inconsistent with the existence of a
spin-down process, as long as it is slow enough. On the other hand, the
background may still exist as long as a moderate fraction of spin energy is
emitted within Hubble time. This stochastic background could be one interesting
target of next generation GW detector network, such as LIGO Voyager, and could
be extracted from total stochastic background.",1712.00784v3
2021-07-19,Reconfigurable Training and Reservoir Computing in an Artificial Spin-Vortex Ice via Spin-Wave Fingerprinting,"Strongly-interacting artificial spin systems are moving beyond mimicking
naturally-occurring materials to emerge as versatile functional platforms, from
reconfigurable magnonics to neuromorphic computing. Typically artificial spin
systems comprise nanomagnets with a single magnetisation texture: collinear
macrospins or chiral vortices. By tuning nanoarray dimensions we achieve
macrospin/vortex bistability and demonstrate a four-state metamaterial
spin-system 'Artificial Spin-Vortex Ice' (ASVI). ASVI can host Ising-like
macrospins with strong ice-like vertex interactions, and weakly-coupled
vortices with low stray dipolar-field. Vortices and macrospins exhibit
starkly-differing spin-wave spectra with analogue-style mode-amplitude control
and mode-frequency shifts of df = 3.8 GHz.
  The enhanced bi-textural microstate space gives rise to emergent physical
memory phenomena, with ratchet-like vortex training and history-dependent
nonlinear fading memory when driven through global field cycles. We employ
spin-wave microstate fingerprinting for rapid, scaleable readout of vortex and
macrospin populations and leverage this for spin-wave reservoir computation.
ASVI performs linear and non-linear mapping transformations of diverse input
signals as well as chaotic time-series forecasting. Energy costs of machine
learning are spiralling unsustainably, developing low-energy neuromorphic
computation hardware such as ASVI is crucial to achieving a zero-carbon
computational future.",2107.08941v3
2022-12-16,Spin excitations in the kagome-lattice metallic antiferromagnet Fe$_{0.89}$Co$_{0.11}$Sn,"Kagome-lattice materials have attracted tremendous interest due to the broad
prospect for seeking superconductivity, quantum spin liquid states, and
topological electronic structures. Among them, the transition-metal kagome
lattices are high-profile objects for the combination of topological
properties, rich magnetism, and multiple-orbital physics. Here we report an
inelastic neutron scattering study on the spin dynamics of a kagome-lattice
antiferromagnetic metal Fe$_{0.89}$Co$_{0.11}$Sn. Although the magnetic
excitations can be observed up to $\sim$250 meV, well-defined spin waves are
only identified below $\sim$90 meV and can be modeled using Heisenberg exchange
with ferromagnetic in-plane nearest-neighbor coupling $J_1$, in-plane
next-nearest-neighbor coupling $J_2$, and antiferromagnetic (AFM) interlayer
coupling $J_c$ under linear spin-wave theory. Above $\sim$90 meV, the spin
waves enter the itinerant Stoner continuum and become highly damped
particle-hole excitations. At the K point of the Brillouin zone, we reveal a
possible band crossing of the spin wave, which indicates a potential Dirac
magnon. Our results uncover the evolution of the spin excitations from the
planar AFM state to the axial AFM state in Fe$_{0.89}$Co$_{0.11}$Sn, solve the
magnetic Hamiltonian for both states, and confirm the significant influence of
the itinerant magnetism on the spin excitations.",2212.08590v2
2005-03-17,Transverse Spin-Orbit Force in the Spin Hall Effect in Ballistic Semiconductor Wires,"We introduce the spin and momentum dependent {\em force operator} which is
defined by the Hamiltonian of a {\em clean} semiconductor quantum wire with
homogeneous Rashba spin-orbit (SO) coupling attached to two ideal (i.e., free
of spin and charge interactions) leads. Its expectation value in the
spin-polarized electronic wave packet injected through the leads explains why
the center of the packet gets deflected in the transverse direction. Moreover,
the corresponding {\em spin density} will be dragged along the transverse
direction to generate an out-of-plane spin accumulation of opposite signs on
the lateral edges of the wire, as expected in the phenomenology of the spin
Hall effect, when spin-$\uparrow$ and spin-$\downarrow$ polarized packets
(mimicking the injection of conventional unpolarized charge current) propagate
simultaneously through the wire. We also demonstrate that spin coherence of the
injected spin-polarized wave packet will gradually diminish (thereby
diminishing the ``force'') along the SO coupled wire due to the entanglement of
spin and orbital degrees of freedom of a single electron, even in the absence
of any impurity scattering.",0503415v2
2020-11-17,Observational Constraints on Black Hole Spin,"The spin of a black hole is an important quantity to study, providing a
window into the processes by which a black hole was born and grew. Further,
spin can be a potent energy source for powering relativistic jets and energetic
particle acceleration. In this review, I describe the techniques currently used
to detect and measure the spins of black holes. It is shown that: (1) Two well
understood techniques, X-ray reflection spectroscopy and thermal continuum
fitting, can be used to measure the spins of black holes that are accreting at
moderate rates. There is a rich set of other electromagnetic techniques
allowing us to extend spin measurements to lower accretion rates. (2) Many
accreting supermassive black holes are found to be rapidly-spinning, although a
population of more slowly spinning black holes emerges at masses above
$M>3\times 10^7\,M_\odot$ as expected from recent structure formation models.
(3) Many accreting stellar-mass black holes in X-ray binary systems are rapidly
spinning and must have been born in this state. (4) The advent of gravitational
wave astronomy has enabled the detection of spin effects in merging binary
black holes. Most of the pre-merger black holes are found to be slowly
spinning, a notable exception being an object that may itself be a merger
product. (5) The stark difference in spins between the black hole X-ray binary
and the binary black hole populations shows that there is a diversity of
formation mechanisms. Given the array of new electromagnetic and gravitational
wave capabilities currently being planned, the future of black hole spin
studies is bright.",2011.08948v1
2020-07-17,A new spin on LIGO-Virgo binary black holes,"Gravitational waves from binary black holes have the potential to yield
information on both of the intrinsic parameters that characterize the compact
objects: their masses and spins. While the component masses are usually
resolvable, the component spins have proven difficult to measure. This
limitation stems in great part from our choice to inquire about the spins of
the most and least massive objects in each binary, a question that becomes
ill-defined when the masses are equal. In this paper we show that one can ask a
different question of the data: what are the spins of the objects with the
highest and lowest dimensionless spins in the binary? We show that this can
significantly improve estimates of the individual spins, especially for binary
systems with comparable masses. When applying this parameterization to the
first 13 gravitational-wave events detected by the LIGO-Virgo collaboration
(LVC), we find that the highest-spinning object is constrained to have nonzero
spin for most sources and to have significant support at the Kerr limit for
GW151226 and GW170729. A joint analysis of all the confident binary black hole
detections by the LVC finds that, unlike with the traditional parametrization,
the distribution of spin magnitude for the highest-spinning object has
negligible support at zero spin. Regardless of the parameterization used, the
configuration where all of the spins in the population are aligned with the
orbital angular momentum is excluded from the 90% credible interval for the
first ten events and from the 99% credible interval for all current confident
detections.",2007.09156v2
2014-01-08,Dynamic exchange via spin currents in acoustic and optical modes of ferromagnetic resonance in spin-valve structures,"Two ferromagnetic layers magnetically decoupled by a thick normal metal
spacer layer can be, nevertheless, dynamically coupled via spin currents
emitted by the spin-pump and absorbed through the spin-torque effects at the
neighboring interfaces. A decrease of damping in both layers due to a partial
compensation of the angular momentum leakage in each layer was previously
observed at the coincidence of the two ferromagnetic resonances. In case of
non-zero magnetic coupling, such a dynamic exchange will depend on the mutual
precession of the magnetic moments in the layers. A difference in the linewidth
of the resonance peaks is expected for the acoustic and optical regimes of
precession. However, the interlayer coupling hybridizes the resonance responses
of the layers and therefore can also change their linewidths. The interplay
between the two mechanisms has never been considered before. In the present
work, the joint influence of the hybridization and non-local damping on the
linewidth has been studied in weakly coupled NiFe/CoFe/Cu/CoFe/MnIr spin-valve
multilayers. It has been found that the dynamic exchange by spin currents is
different in the optical and acoustic modes, and this difference is dependent
on the interlayer coupling strength. In contrast to the acoustic precession
mode, the dynamic exchange in the optical mode works as an additional damping
source. A simulation in the framework of the Landau-Lifshitz-Gilbert formalism
for two ferromagnetic layers coupled magnetically and by spin currents has been
done to separate the effects of the non-local damping from the resonance modes
hybridization. In our samples both mechanisms bring about linewidth changes of
the same order of magnitude, but lead to a distinctly different angular
behavior. The obtained results are relevant for a broad class of coupled
magnetic multilayers with ballistic regime of the spin transport.",1401.1672v1
2022-11-11,Short wavelength electrostatic wave measurement using MMS spacecraft,"Determination of the wave mode of short-wavelength electrostatic waves along
with their generation mechanism requires reliable measurement of the wave
electric field. We investigate the reliability of the electric field
measurement for short-wavelength waves observed by MMS. We develop a method,
based on spin-plane interferometry, to reliably determine the full 3D wave
vector of the observed waves. We test the method on synthetic data and then
apply it to ion acoustic wave bursts measured in situ in the solar wind. By
studying the statistical properties of ion acoustic waves in the solar wind we
retrieve the known results that the wave propagation is predominantly
field-aligned. We also determine the wavelength of the waves. We find that the
distribution peaks at around 100 m, which when normalized to the Debye length
corresponds to scales between 10 and 20 Debye lengths.",2211.06221v1
2008-12-23,Black Holes Admitting Strong Resonant Phenomena,"High-frequency twin peak quasiperiodic oscillations (QPOs) are observed in
four microquasars, i.e., Galactic black hole binary systems, with frequency
ratio very close to 3:2. In the microquasar GRS 1915+105, the structure of QPOs
exhibits additional frequencies, and more than two frequencies are observed in
the Galaxy nuclei Sgr A*, or in some extragalactic sources (NGC 4051,
MCG-6-30-15 and NGC 5408 X-1). The observed QPOs can be explained by a variety
of the orbital resonance model versions assuming resonance of oscillations with
the Keplerian frequency or the vertical epicyclic frequency, and the radial
epicyclic frequency, or some combinations of these frequencies. Generally,
different resonances could arise at different radii of an accretion disc.
However, we have shown that for special values of dimensionless black hole spin
strong resonant phenomena could occur when different resonances can be excited
at the same radius, as cooperative phenomena between the resonances may work in
such situations. The special values of black hole spin are determined for
triple frequency ratio sets \nu_{K} : \nu_{\theta} : \nu_{r} = s:t:u with s, t,
u being small integers. The most promising example of such a special situation
arises for black holes with extraordinary resonant spin a = 0.983 at the radius
r = 2.395 M, where \nu_{K} : \nu_{\theta} : \nu_{r} = 3:2:1. We also predict
that when combinations of the orbital frequencies are allowed, QPOs with four
frequency ratio set 4:3:2:1 could be observed in the field of black holes with
a = 0.866, 0.882 and 0.962. Assuming the extraordinary resonant spin a = 0.983
in Sgr A*, its QPOs with observed frequency ratio very close to 3:2:1 imply the
black hole mass in the interval 4.3 x 10^6 M_sun < M < 5.4 x 10^6 M_sun, in
agreement with estimates given by other, independent, observations.",0812.4418v1
2023-03-30,A search technique to observe precessing compact binary mergers in the advanced detector era,"Gravitational-wave signals from compact binary coalescences are most
efficiently identified through matched filter searches, which match the data
against a pre-generated bank of gravitational-wave templates. Although
different techniques for performing the matched filter, as well as generating
the template bank, exist, currently all modelled gravitational-wave searches
use templates that restrict the component spins to be aligned (or anti-aligned)
with the orbital angular momentum. This means that current searches are less
sensitive to gravitational-wave signals generated from binaries with generic
spins (precessing), suggesting that, potentially, a significant fraction of
signals may remain undetected. In this work we introduce a matched filter
search that is sensitive to signals generated from precessing binaries and can
realistically be used during a gravitational-wave observing run. We take
advantage of the fact that a gravitational-wave signal from a precessing binary
can be decomposed into a power series of five harmonics, to show that a
generic-spin template bank, which is only $\sim 3\times$ larger than existing
aligned-spin banks, is needed to increase our sensitive volume by $\sim 100\%$
for neutron star black hole binaries with total mass larger than $17.5\,
M_{\odot}$ and in-plane spins $>0.67$. In fact, our generic spin search
performs as well as existing aligned-spin searches for neutron star black hole
signals with insignificant in-plane spins, but improves sensitivity by
$\sim60\%$ on average across the full generic spin parameter space. We
anticipate that this improved technique will identify significantly more
gravitational-wave signals, and, ultimately, help shed light on the unknown
spin distribution of binaries in the universe.",2303.17364v1
1995-08-25,Simple theory for spin-lattice relaxation in metallic rare earth ferromagnets,"The spin-lattice relaxation time $\tau_{SL}$ is a key quantity both for the
dynamical response of ferromagnets excited by laser pulses and as the speed
limit of magneto-optical recording. Extending the theory for the electron
paramagnetic resonance of magnetic impurities to spin-lattice relaxation in
ferromagnetic rare earths we calculate $\tau_{SL}$ for Gd and find a value of
48 ps in very good agreement with time-resolved spin-polarized photoemission
experiments. We argue that the time scale for $\tau_{SL}$ in metals is
essentially given by the spin-orbit induced magnetocrystalline anisotropy
energy.",9508120v1
1997-01-28,Variational states for the spin-Peierls system,"We introduce a family of Jastrow pair product states for quasi
one-dimensional spin systems. Depending on a parameter they interpolate between
the resonating valence bond ground state of the Haldane-Shastry model
describing a spin liquid and the (dimerized) valence bond solid ground states
of the Majumdar-Ghosh spin chain. These states are found to form an excellent
basis for variational studies of Heisenberg chains with next nearest neighbour
interaction and bond alternation as realized in the spin-Peierls system
CuGeO_3.",9701200v2
1999-01-22,Superconducting Fluctuation Effects on the Spin-Lattice Relaxation Rate in YBa_2Cu_3O_{6.95},"We report 63Cu(2) spin-lattice relaxation rate measurements of
YBa_2Cu_3O_{6.95} in magnetic fields from 2.1 T to 27.3 T obtained from
17O(2,3) nuclear magnetic resonance spin-spin relaxation. For T < 120 K, the
spin-lattice rate increases with increasing magnetic field. We identify this
magnetic field dependence with the change in the low-energy spectral weight
originating from d-wave pairing fluctuation corrections to the density of
states.",9901230v1
1999-02-09,Spin liquid ground state in a two dimensional non-frustrated spin model,"We consider an exchange model describing two isotropic spin-1/2 Heisenberg
antiferromagnets coupled by a quartic term on the square lattice. The model is
relevant for systems with orbital degeneracy and strong electron-vibron
coupling in the large Hubbard repulsion limit, and is known to show a
spin-Peierls-like dimerization in one dimension. In two dimensions we calculate
energy gaps, susceptibilities, and correlation functions with a Green's
Function Monte Carlo. We find a finite spin gap and no evidence of any kind of
order. We conclude that the ground state is, most likely, a spin liquid of
resonating valence bonds.",9902116v1
1999-10-11,Anomalous spin susceptibility and magnetic polaron formation in the double exchange systems,"The magnetic susceptibility and spin-spin correlation of the double-exchange
model for doped manganites are investigated through the Monte Carlo
calculations on the three-dimensional lattice model. Deviations of the
susceptibility from the Curie-Weiss behavior above the ferromagnetic ordering
temperature $T_c$ seem to indicate a formation of local ferromagnetic clusters
in the vicinity of $T_c$, which is consistent with recent electron paramagnetic
resonance experiments for La$_{2/3}$Ca$_{1/3}$MnO$_3$. A further analysis of
the spin-spin correlations show the ferromagnetic cluster size to be
three-to-four lattice spacings, suggesting that the charge carriers may form
magnetic polarons.",9910153v1
2001-04-04,Bound spin-excitons in two-dimensional electron gas,"A theory of the spin exciton capture by a magnetic impurity in a 2D electron
gas is developed. We consider the resonance model for electron scattering by a
transition metal impurity and calculate the binding potential for spin
excitons. This potential is spin selective and is capable of binding a spin
exciton with zero angular momentum. In order to trap an exciton with a nonzero
angular momentum m, the potential must exceed a certain threshold value,
depending on m.",0104074v1
2001-06-08,Polarization of the helf-filled Landau level in quantum Hall effect,"We develop a theory of the half-filled Landau level which shows that it is a
two-component fluid. One of the components has spin up and the other spin down
so that the electron-spin resonance can occur. The 1/3 filled level is fully
spin polarized one-component fluid. We calculate the spin polarization at the
half-filled band as a function of temperature and compare the calculated
results with the experimentally measured value. Our theory is in very good
agreement with the experimental data of the polarization obtained from the
ratio of the Knight shifts.",0106160v1
2002-04-16,Spin accumulation in ferromagnetic single-electron transistors in the cotunneling regime,"We propose a new method of direct detection of spin accumulation, which
overcomes problems of previous measurement schemes. A spin dependent current in
a single-electron transistor with ferromagnetic electrodes leads to spin
accumulation on the metallic island. The resulting spin-splitting of the
electrochemical potentials of the island, because of an additional shift by the
charging energy, can be detected from the spacing between two resonances in the
current-voltage characteristics. The results were obtained in the framework of
a real-time diagrammatic approach which allows to study higher order
(co-)tunneling processes in the strong nonequlibrium situation.",0204354v1
2003-02-18,Flow equation renormalization of a spin-boson model with a structured bath,"We discuss the dynamics of a spin coupled to a damped harmonic oscillator.
This system can be mapped to a spin-boson model with a structured bath, i.e.
the spectral function of the bath has a resonance peak. We diagonalize the
model by means of infinitesimal unitary transformations (flow equations),
thereby decoupling the small quantum system from its environment, and calculate
spin-spin correlation functions.",0302357v1
2003-04-04,Dynamic exchange coupling and Gilbert damping in magnetic multilayers,"We theoretically study dynamic properties of thin ferromagnetic films in
contact with normal metals. Moving magnetizations cause a flow of spins into
adjacent conductors, which relax by spin flip, scatter back into the
ferromagnet, or are absorbed by another ferromagnet. Relaxation of spins
outside the moving magnetization enhances the overall damping of the
magnetization dynamics in accordance with the Gilbert phenomenology. Transfer
of spins between different ferromagnets by these nonequilibrium spin currents
leads to a long-ranged dynamic exchange interaction and novel collective
excitation modes. Our predictions agree well with recent
ferromagnetic-resonance experiments on ultrathin magnetic films.",0304116v1
2003-05-20,Spin-dependent Rabi oscillations in single quantum=0D dot,"Ultrafast optical pump of exciton resonance in single quantum dot by an
elliptically polarized laser pulse is described by the non-Markov balance
equations. Population and spin dynamics are investigated and spin-dependent
Rabi oscillations are considered for the case of a flat quantum dot, with the
lateral size greater than the height. The following peculiarities of temporal
evolution have been found: a) a beating of Rabi oscillations under an
elliptically polarized pump and b) quenching of spin orientation due to a
spin-orbit splitting effect.",0305473v1
2004-07-15,Optically induced spin polarization of an electric current through a quantum dot,"We examine electron transport through semiconductor quantum dot subject to a
continuous circularly polarized optical irradiation resonant to the electron -
heavy hole transition. Electrons having certain spin polarization experience
Rabi oscillation and their energy levels are shifted by the Rabi frequency.
Correspondingly, the equilibrium chemical potential of the leads and the
lead-to-lead bias voltage can be adjusted so only electrons with spin-up
polarization or only electrons with spin-down polarization contribute to the
current. The temperature dependence of the spin polarization of the current is
also discussed.",0407376v2
2005-05-09,Fast exciton spin relaxation in single quantum dots,"Exciton spin relaxation is investigated in single epitaxially grown
semiconductor quantum dots in order to test the expected spin relaxation
quenching in this system. We study the polarization anisotropy of the
photoluminescence signal emitted by isolated quantum dots under steady-state or
pulsed non-resonant excitation. We find that the longitudinal exciton spin
relaxation time is strikingly short ($\leq$100 ps) even at low temperature.
This result breaks down the picture of a frozen exciton spin in quantum dots.",0505210v1
2005-06-14,Spin superradiance versus atomic superradiance,"A comparative analysis is given of spin superradiance and atomic
superradiance. Their similarities and distinctions are emphasized. It is shown
that, despite a close analogy, these phenomena are fundamentally different. In
atomic systems, superradiance is a self-organized process, in which both the
initial cause, being spontaneous emission, as well as the collectivizing
mechanism of their interactions through the common radiation field, are of the
same physical nature. Contrary to this, in actual spin systems with dipole
interactions, the latter are the major reason for spin motion. Electromagnetic
spin interactions through radiation are negligible and can never produce
collective effects. The possibility of realizing superradiance in molecular
magnets by coupling them to a resonant circuit is discussed.",0506322v1
2007-03-30,Spin-polarized tunneling microscopy and the Kondo effect,"We present a theory for spin-polarized scanning tunneling microscopy (SP-STM)
of a Kondo impurity on an unpolarized metallic substrate. The spin polarization
of the SP-STM breaks the spin symmetry of the Kondo system, similar to an
applied magnetic field, leading to a splitting of the Abrikosov-Suhl-Kondo
resonance. The amount of splitting is controlled by the strength of the
coupling between the impurity and the SP-STM tip and also the overall spin
polarization of the SP-STM.",0703813v1
1998-05-11,The $π-$Gluon Exchange Interaction Between Constituent Quarks,"The interaction mediated by irreducible pion and gluon exchange between
constituent quarks is calculated and shown to have a strong tensor component,
which tends to cancel the pion exchange tensor interaction between quarks. Its
spin-spin component is somewhat weaker than the pion exchange spin-spin
interaction, while its central and spin-orbit components are small in
comparison to the corresponding single gluon exchange interactions. The
combination of the $\pi-$gluon exchange interaction with the single pion
exchange interaction and a weak gluon exchange interaction between constituent
quarks has the qualitative features required for understanding the hyperfine
splittings of the spectra of the nucleon and the $\Delta$ resonances.",9805280v1
2000-03-21,Ortho-Para Conversion in CH3F. Self-Consistent Theoretical Model,"A complete theoretical model of the nuclear spin conversion in 13CH3F induced
by intramolecular ortho-para state mixing is proposed. The model contains
parameters determined from the level-crossing spectra of the 13CH3F spin
conversion. This set of parameters includes the ortho-para decoherence rate,
the magnitude of the hyperfine spin-spin interaction between the molecular
nuclei and the energy gap between the mixed ortho and para states. These
parameters are found to be in a good agreement with their theoretical
estimates.",0003046v1
2001-06-17,Sub-Riemannian Geometry and Time Optimal Control of Three Spin Systems: Quantum Gates and Coherence Transfer,"Many coherence transfer experiments in Nuclear Magnetic Resonance
Spectroscopy, involving network of coupled spins, use temporary spin-decoupling
to produce desired effective Hamiltonians. In this paper, we show that
significant time can be saved in producing an effective Hamiltonian, if
spin-decoupling is avoided. We provide time optimal pulse sequences for
producing an important class of effective Hamiltonians in three spin networks.
These effective Hamiltonians are useful for coherence transfer experiments and
implementation of quantum logic gates in NMR quantum computing. It is
demonstrated that computing these time optimal pulse sequences can be reduced
to geometric problems that involve computing sub-Riemannian geodesics on
Homogeneous spaces.",0106099v1
2001-11-29,Conditional Spin Resonance with Trapped Ions,"Internal states of different ions in an electrodynamic trap are coupled when
a static magnetic field is applied -- analogous to spin-spin coupling in
molecules used for NMR. This spin-spin interaction can be used, for example, to
implement quantum logic operations in ion traps using NMR methods. The
collection of trapped ions can be viewed as a $N$-qubit molecule with
adjustable coupling constants.",0111158v1
2003-03-28,Spin Relaxation Caused by Thermal Excitations of High Frequency Modes of Cantilever Vibrations,"We consider the process of spin relaxation in the oscillating
cantilever-driven adiabatic reversals technique in magnetic resonance force
microscopy. We simulated the spin relaxation caused by thermal excitations of
the high frequency cantilever modes in the region of the Rabi frequency of the
spin sub-system. The minimum relaxation time obtained in our simulations is
greater but of the same order of magnitude as one measured in recent
experiments. We demonstrated that using a cantilever with nonuniform
cross-sectional area may significantly increase spin relaxation time.",0303171v1
2004-10-18,Spin Squeezing via One-Axis Twisting with Coherent Light,"We propose a new method of spin squeezing of atomic spin, based on the
interactions between atoms and off-resonant light which are known as
paramagnetic Faraday rotation and fictitious magnetic field of light. Since the
projection process, squeezed light, or special interactions among the atoms are
not required in this method, it can be widely applied to many systems. The
attainable range of the squeezing parameter is S^{-2/5}, where S is the total
spin, which is limited by additional fluctuations imposed by coherent light and
the spherical nature of the spin distribution.",0410132v1
2005-12-07,Paramagnetic Faraday rotation with spin-polarized ytterbium atoms,"We report observation of the paramagnetic Faraday rotation of spin-polarized
ytterbium (Yb) atoms. As the atomic samples, we used an atomic beam, released
atoms from a magneto-optical trap (MOT), and trapped atoms in a
far-off-resonant trap (FORT). Since Yb is diamagnetic and includes a spin-1/2
isotope, it is an ideal sample for the spin physics, such as quantum
non-demolition measurement of spin (spin QND), for example. From the results of
the rotation angle, we confirmed that the atoms were almost perfectly
polarized.",0512056v2
2007-04-10,Spin-dependence of Ce $4f$ hybridization in magnetically ordered systems: A spin-resolved photoemission study of Ce/Fe(110),"Spin- and angle-resolved resonant (Ce $4d\to4f$) photoemission spectra of a
monolayer Ce on Fe(110) reveal spin-dependent changes of the Fermi-level peak
intensities. That indicate a spin-dependence of $4f$ hybridization and, thus,
of $4f$ occupancy and local moment. The phenomenon is described in the
framework of the periodic Anderson model by $4f$ electron hopping into the
exchange split Fe 3d derived bands that form a spin-gap at the Fermi energy
around the $\bar{\Gamma}$ point of the surface Brillouin zone.",0704.1254v1
2008-11-13,Optical spin orientation of a single manganese atom in a quantum dot,"A hight degree of spin polarization is achieved for a Mn atom localized in a
semiconductor quantum dot using quasi-resonant optical excitation at zero
magnetic field. Optically created spin polarized carriers generate an energy
splitting of the Mn spin and enable magnetic moment orientation controlled by
the photon helicity and energy. The dynamics and the magnetic field dependence
of the optical pumping mechanism shows that the spin lifetime of an isolated Mn
atom at zero magnetic field is controlled by a magnetic anisotropy induced by
the built-in strain in the quantum dots.",0811.2165v1
2009-06-23,Multiferroic oxides-based flash-memory and spin-field-effect transistor,"We propose a modified spin-field-effect transistor fabricated in a two
dimensional electron gas (2DEG) formed at the surface of multiferroic oxides
with a transverse helical magnetic order. The topology of the oxide local
magnetic moments induces a resonant momentum-dependent effective spin-orbit
interaction acting on 2DEG. We show that spin polarization dephasing is
strongly suppressed which is crucial for functionality. The carrier spin
precession phase depend linearly on the magnetic spiral helicity. The latter is
electrically controllable by virtue of the magento-electric effect. We also
suggest a flash-memory device based on this structure.",0906.4210v1
2009-09-13,Manipulation of Non-classical Atomic Spin States,"We report successful manipulation of non-classical atomic spin states. We
generate squeezed spin states by a spin quantum nondemolition measurement, and
apply an off-resonant circularly-polarized light pulse to the atoms. By
changing the pulse duration, we have clearly observed a rotation of anisotropic
quantum noise distribution in good contrast with the case of manipulation of a
coherent spin state where the quantum noise distribution is always isotropic.
This is an important step for quantum state tomography, quantum swapping, and
precision spectroscopic measurement.",0909.2423v1
2010-11-11,Proposal for a Topological Plasmon Spin Rectifier,"We propose a device in which the spin-polarized AC plasmon mode in the
surface state of a topological insulator nanostructure induces a static spin
accumulation in a resonant, normal metal structure coupled to it. Using a
finite-difference time-domain model, we simulate this spin-pump mechanism with
drift, diffusion, relaxation, and precession in a magnetic field. This
optically-driven system can serve as a DC ""spin battery"" for spintronic
devices.",1011.2697v2
2010-12-04,The Beauty of Spin,"I review recent developments in theoretical spin physics. Topics include pion
production in nucleon-nucleon collisions, the implications of heavy quark spin
symmetry for heavy hadron molecules, the nucleon electric dipole form factors
and ab initio calculations of the width of hadron resonances. A few spin
physics high-lights from experiments at the COSY accelerator are also
discussed.",1012.0924v1
2011-01-12,The Spin-Exchange Dynamical Structure Factor of the S=1/2 Heisenberg Chain,"We determine the spin-exchange dynamical structure factor of the Heisenberg
spin chain, as is measured by indirect Resonant Inelastic X-ray Scattering
(RIXS). We find that two-spin RIXS excitations nearly entirely fractionalize
into *two spinon* states. These share the same continuum lower bound as
single-spin neutron scattering excitations, even if the relevant final states
belong to orthogonal symmetry sectors. The RIXS spectral weight is mainly
carried by higher-energy excitations, and is beyond the reach of the low-energy
effective theories of Luttinger liquid type.",1101.2356v1
2011-01-25,Inelastic electron tunneling spectroscopy of a single nuclear spin,"Detection of a single nuclear spin constitutes an outstanding problem in
different fields of physics such as quantum computing or magnetic imaging. Here
we show that the energy levels of a single nuclear spin can be measured by
means of inelastic electron tunneling spectroscopy (IETS).
  We consider two different systems, a magnetic adatom probed with STM and a
single Bi dopant in a Silicon nanotransistor. We find that the hyperfine
coupling opens new transport channels which can be resolved at experimentally
accessible temperatures. Our simulations evince that IETS yield information
about the occupation of the nuclear spin states, paving the way towards
transport-detected single nuclear spin resonance.",1101.4772v1
2011-06-28,Phase separation in a polarized Fermi gas with spin-orbit coupling,"We study the phase separation of a spin polarized Fermi gas with spin-orbit
coupling near a wide Feshbach resonance. As a result of the competition between
spin-orbit coupling and population imbalance, the phase diagram for a uniform
gas develops a rich structure of phase separation involving gapless superfluid
states which are topologically non-trivial. We find that these novel gapless
phases can be stabilized by intermediate spin-orbit coupling strengths. We then
demonstrate the phase separation induced by an external trapping potential and
discuss the optimal parameter region for the experimental observation of the
gapless superfluid phases.",1106.5667v2
2011-08-02,Quantum read-out and fast initialization of nuclear spin qubits with electric currents,"Nuclear spin qubits have the longest coherence times in the solid state, but
their quantum read-out and initialization is a great challenge. We present a
theory for the interaction of an electric current with the nuclear spins of
donor impurities in semiconductors. The theory yields a sensitivity criterion
for quantum detection of nuclear spin states using electrically detected
magnetic resonance, as well as an all electrical method for fast nuclear spin
qubit initialization.",1108.0699v3
2011-11-06,Estimation of Coupling Constants of a Three-Spin Chain: Case Study of Hamiltonian Tomography with NMR,"It has been shown that inter-spin interaction strengths in a spins-1/2 chain
can be evaluated by accessing one of the edge spins only. We demonstrate this
experimentally for the simplest case, a three-spin chain, with nuclear magnetic
resonance (NMR) technique. The three spins in the chain interact through
nearest-neighbor Ising interactions under site-dependent transverse fields. The
employed molecule is an alanine containing three $^{13}$C nuclei, each of which
has spin-1/2.",1111.1381v1
2011-12-05,Optomechanically-Based Probing of Spin-Charge Separation in Ultracold Gases,"We propose a new approach to investigate the spin-charge separation in 1D
quantum liquids via the optomechanical coupled atom-cavity system. We show
that, one can realize an effective two-modes optomechanical model with the
spin/charge modes playing the role of mechanical resonators. By tuning the weak
probe laser under a pump field, the signal of spin-charge separation could be
probed explicitly in the sideband regime via cavity transmissions. Moreover,
the spin/charge modes can be addressed separately by designing the probe field
configurations, which may be beneficial for future studies of the atom-cavity
systems and quantum many-body physics.",1112.0843v1
2012-10-30,NMR relaxation in spin ice due to diffusing emergent monopoles,"At low temperatures, spin dynamics in ideal spin ice is due mainly to dilute,
thermally excited magnetic monopole excitations. I consider how these will
affect the dynamics of a nuclear spin (the same theory applies to muon spin
resonance if implanted muons do not diffuse). Up to the time scale for nearby
monopoles to be rearranged, a stretched-exponential form of the relaxation
functions is expected. I work out the expected exponent in that exponential and
the formulas for the $T_1$ (longitudinal) and $T_2$ (dephasing) relaxations, as
a function of the monopole density. Experimental NMR is incompatible with the
predictions and I suggest is due to magnetic impurities.",1210.8137v1
2012-11-01,Renormalization of spin-rotation coupling,"We predict the enhancement of the spin-rotation coupling due to the interband
mixing. The Bloch wavefunctions in the presence of mechanical rotation are
constructed with the generalized crystal momentum which includes a gauge
potential arising from the rotation. Using the eight- band Kane model, the
renormalized spin-rotation coupling is explicitly obtained. As a result of the
renormalization, the rotational Doppler shift in electron spin resonance and
the mechanical torque on an electron spin will be strongly modulated.",1211.0127v2
2013-01-29,Model of coherent optical spin manipulation through hot trion states in p-doped InAs/GaAs quantum dots,"A new generalised group-theoretical approach, based on master
Maxwell-pseudospin equations, is proposed to explain recently observed enhanced
circular dichroism in the excited state emission from p-doped quantum dot
ensembles under resonant circularly polarised excitation into hot trion states,
herein referred to as ""spin-filtering effect"". The theory agrees remarkably
well with polarised time-resolved photoluminescence experiments, yielding
largely unknown inter- and intra-shell spin relaxation time scales. This
approach allows to predict optimum pulse parameters for control of spin
dynamics, which will enable exploitation of the effect in all-optical
spin-based quantum technologies.",1301.7018v1
2013-02-26,Spin noise of exciton-polaritons in microcavities,"We develop a theory of spin fluctuations of exciton-polaritons in a
semiconductor microcavity under the non-resonant unpolarized pumping. It is
shown that the corresponding spin noise is sensitive to the scattering rates in
the system, occupation of the ground state, statistics of polaritons, and
interactions. The spin noise spectrum drastically narrows in the polariton
lasing regime due to formation of a polariton condensate, while its shape can
become non-Lorentzian owing to interaction-induced spin decoherence.",1302.6439v2
2013-03-05,Resolving an Individual One-Proton Spin Flip to Determine a Proton Spin State,"Previous measurements with a single trapped proton or antiproton detected
spin resonance from the increased scatter of frequency measurements caused by
many spin flips. Here a measured correlation confirms that individual spin
transitions and states are detected instead. The high fidelity suggests that it
may be possible to use quantum jump spectroscopy to measure the p and \pbar
magnetic moments much more precisely.",1303.0924v2
2013-05-10,Noise and fluctuation relations of a spin diode,"We consider fluctuation relations between the transport coefficients of a
spintronic system where magnetic interactions play a crucial role. We
investigate a prototypical spintronic device (a spin-diode) which consists of
an interacting resonant level coupled to two ferromagnetic electrodes. We
thereby obtain the cumulant generating function for the spin transport in the
sequential tunnelling regime. We demonstrate the fulfilment of the nonlinear
fluctuation relations when up and down spin currents are correlated in the
presence of both spin-flip processes and external magnetic fields.",1305.2346v1
2013-08-25,Entanglement of spin-orbit qubits induced by Coulomb interaction,"Spin-orbit qubit (SOQ) is the dressed spin by the orbital degree of freedom
through a strong spin-orbit coupling. We show that Coulomb interaction between
two electrons in quantum dots located separately in two nanowires can
efficiently induce quantum entanglement between two SOQs. The physical
mechanism to achieve such quantum entanglement is based on the feasibility of
the SOQ responding to the external electric field via an intrinsic electric
dipole spin resonance.",1308.5387v1
2013-12-23,Colossal Spin Hall Effect in Ultrathin Metallic Films,"We predict spin Hall angles up to 80% for ultrathin noble metal films with
substitutional Bi impurities. The colossal spin Hall effect is caused by
enhancement of the spin Hall conductivity in reduced sample dimension and a
strong reduction of the charge conductivity by resonant impurity scattering.
These findings can be exploited to create materials with high efficiency of
charge to spin current conversion by strain engineering.",1312.6539v1
2014-11-20,Spin transport and polarization properties of manganese-doped dual-guanine molecule,"We study the spin transport and polarization properties of manganese-doped
dual-guanine molecules connected to graphene leads using non-equilibrium
Green's function method. It is shown that a manganese doped dual-guanine
molecule is a biological semiconductor and behaves as a prefect spin filter. We
show that this semiconductor can behave as a spin switch when the Rashba
spin-orbit interaction is considered. In addition, it is shown that, a large
conductance is observed due to the Fano-Kondo-Rashba resonance effect.",1411.5448v1
2015-02-03,Generation of Spin Currents in the Skyrmion Phase of a Helimagnetic Insulator $\mathrm{Cu_2OSeO_3}$,"We report spin-current generation related with skyrmion dynamics resonantly
excited by a microwave in a helimagnetic insulator $\mathrm{Cu_2OSeO_3}$. A Pt
layer was fabricated on $\mathrm{Cu_2OSeO_3}$ and voltage in the Pt layer was
measured upon magnetic resonance of $\mathrm{Cu_2OSeO_3}$ to electrically
detect injected spin currents via the inverse spin Hall effect (ISHE) in Pt. We
found that ISHE-induced electromotive forces appear in the skyrmion phase of
$\mathrm{Cu_2OSeO_3}$ as well as in the ferrimagnetic phase, which shows that
magnetic skyrmions can contribute to the spin pumping effect.",1502.00742v1
2015-02-19,Enhanced photogalvanic effect in graphene due to Rashba spin-orbit coupling,"We analyze theoretically optical generation of a spin-polarized charge
current (photogalvanic effect) and spin polarization in graphene with Rashba
spin-orbit coupling. An external magnetic field is applied in the graphene
plane, which plays a crucial role in the mechanism of current generation. We
predict a highly efficient resonant-like photogalvanic effect in a narrow
frequency range which is determined by the magnetic field. A relatively less
efficient photogalvanic effect appears in a broader frequency range, determined
by the electron concentration and spin-orbit coupling strength.",1502.05683v1
2015-09-07,Time-optimal polarization transfer from an electron spin to a nuclear spin,"Polarization transfers from an electron spin to a nuclear spin are essential
for various physical tasks, such as dynamic nuclear polarization in nuclear
magnetic resonance and quantum state transformations on hybrid electron-nuclear
spin systems. We present time-optimal schemes for electron-nuclear polarization
transfers which improve on conventional approaches and will have wide
applications.",1509.02072v1
2016-05-21,Electrically tunable quantum interfaces between photons and spin qubits in carbon nanotube quantum dots,"We present a new scheme for quantum interfaces to accomplish the
interconversion of photonic qubits and spin qubits based on optomechanical
resonators and the spin-orbit-induced interactions in suspended carbon nanotube
quantum dots. This interface implements quantum spin transducers and further
enables electrical manipulation of local electron spin qubits, which lays the
foundation for all-electrical control of state transfer protocols between two
distant quantum nodes in a quantum network. We numerically evaluate the state
transfer processes and proceed to estimate the effect of each coupling strength
on the operation fidelities.",1605.06649v1
2016-06-09,Experimental Verification of a Spin-Interference Device Action,"We report the detection of spin interference signal in an Aharonov-Bohm type
interferometer with quantum dots on the conduction paths. We have found that
resonators like quantum dots can work as efficient spin rotators. The
interference signal appears only when spin-polarized electrons are injected
into the device. The interference pattern in the gate voltage-magnetic field
plane is checker board like, ensuring the modulation of spin wavefunction's
phase as well as the orbital phase.",1606.02876v2
2018-10-07,Tri-spin dynamics in alkali metal-noble gas NMR gyroscope,"Alkali metal-noble gas NMR gyroscope is widely used for precision rotation
measurement in fundamental and applied physics. By numerically simulating the
alkali-nuclear-nuclear tri-spin dynamics, we investigate the dependence of
gyroscope response on alkali spin relaxation time and nuclear spin
magnetization. We found additional resonance peaks appear due to a new source
of instability, namely the inherent multistability of tri-spin dynamics. The
numerical simulation results agree well with the recent experiment, enabling a
better understanding and exploitation of the gyroscope signal.",1810.03185v4
2012-09-12,New insights into the spin structure of the nucleon,"We analyze the low-energy spin structure of the nucleon in a covariant
effective field theory with explicit spin-3/2 degrees of freedom to third order
in the small scale expansion. Using the available data on the strong and
electromagnetic width of the Delta-resonance, we give parameter-free
predictions for various spin-polarizabilities and moments of spin structure
functions. We find an improved description of the nucleon spin structure at
finite photon virtualities for some observables and point out the necessity of
a fourth order calculation.",1209.2523v1
2021-04-27,Vector resonances spin alignement as a probe of spin hydrodynamics and freeze-out,"We argue that a detailed analysis of the spin alignement of vector mesons can
serve as a probe of two little-understood aspects of spin dynamics in the
vortical fluid: The degree of relaxation between vorticity and parton spin
polarization, and the degree of coherence of the hadron wavefunction at
freeze-out.
  We illustrate these with a coalescence model.",2104.12941v4
2021-05-07,Proposed rapid detection of nuclear spins with entanglement-enhanced sensors,"Recently, there have been significant developments to detect nuclear spins
with an nitrogen vacancy (NV) center in diamond. However, due to the nature of
the short range dipole-dipole interaction, it takes a long time to detect
distant nuclear spins with the NV centers. Here, we propose a rapid detection
of nuclear spins with an entanglement between the NV centers. We show that the
necessary time to detect the nuclear spins with the entanglement is several
orders of magnitude shorter than that with separable NV centers. Our result
pave the way for new applications in nanoscale nuclear magnetic resonance
spectroscopy.",2105.03069v1
2022-02-28,Optical measurement of electron spins in quantum dots: Quantum Zeno effects,"We describe the effects of the quantum back action under continuous optical
measurement of electron spins in quantum dots. We consider the system
excitation by elliptically polarized light close to the trion resonance, which
allows for the simultaneous spin orientation and measurement. We
microscopically demonstrate that the nuclei-induced spin relaxation can be both
suppressed and accelerated by the continuous spin measurement due to the
quantum Zeno and anti-Zeno effects, respectively. Our theoretical predictions
can be directly compared with the future experimental results and
straightforwardly generalized for the pump-probe experiments.",2202.13994v1
2007-12-14,Quantum Spin Excitations through the metal-to-insulator crossover in $Y Ba_2 Cu_3 O_{6+y}$,"We use inelastic neutron scattering to study the temperature dependence of
the spin excitations of a detwinned superconducting YBa$_2$Cu$_3$O$_{6.45}$
($T_c=48$ K). In contrast to earlier work on YBa$_2$Cu$_3$O$_{6.5}$ ($T_c=58$
K), where the prominent features in the magnetic spectra consist of a sharp
collective magnetic excitation termed ``resonance'' and a large
($\hbar\omega\approx 15$ meV) superconducting spin gap, we find that the spin
excitations in YBa$_2$Cu$_3$O$_{6.45}$ are gapless and have a much broader
resonance. Our detailed mapping of magnetic scattering along the
$a^\ast$/$b^\ast$-axis directions at different energies reveals that spin
excitations are unisotropic and consistent with the ``hourglass''-like
dispersion along the $a^\ast$-axis direction near the resonance, but they are
isotropic at lower energies. Since a fundamental change in the low-temperature
normal state of YBa$_2$Cu$_3$O$_{6+y}$ when superconductivity is suppressed
takes place at $y\sim0.5$ with a metal-to-insulator crossover (MIC), where the
ground state transforms from a metallic to an insulating-like phase, our
results suggest a clear connection between the large change in spin excitations
and the MIC. The resonance therefore is a fundamental feature of metallic
ground state superconductors and a consequence of high-$T_c$ superconductivity.",0712.2465v1
2013-01-22,Validity of single-channel model for a spin-orbit coupled atomic Fermi gas near Feshbach resonances,"We theoretically investigate a Rashba spin-orbit coupled Fermi gas near
Feshbach resonances, by using mean-field theory and a two-channel model that
takes into account explicitly Feshbach molecules in the close channel. In the
absence of spin-orbit coupling, when the channel coupling $g$ between the
closed and open channels is strong, it is widely accepted that the two-channel
model is equivalent to a single-channel model that excludes Feshbach molecules.
This is the so-called broad resonance limit, which is well-satisfied by
ultracold atomic Fermi gases of $^{6}$Li atoms and $^{40}$K atoms in current
experiments. Here, with Rashba spin-orbit coupling we find that the condition
for equivalence becomes much more stringent. As a result, the single-channel
model may already be insufficient to describe properly an atomic Fermi gas of
$^{40}$K atoms at a moderate spin-orbit coupling. We determine a characteristic
channel coupling strength $g_{c}$ as a function of the spin-orbit coupling
strength, above which the single-channel and two-channel models are
approximately equivalent. We also find that for narrow resonance with small
channel coupling, the pairing gap and molecular fraction is strongly suppressed
by SO coupling. Our results can be readily tested in $^{40}$K atoms by using
optical molecular spectroscopy.",1301.5071v1
2015-03-05,Monitoring surface resonances on Co2MnSi(100) by spin-resolved photoelectron spectroscopy,"The magnitude of the spin polarization at the Fermi level of ferromagnetic
materials at room temperature is a key property for spintronics. Investigating
the Heusler compound Co$_2$MnSi a value of 93$\%$ for the spin polarization has
been observed at room temperature, where the high spin polarization is related
to a stable surface resonance in the majority band extending deep into the
bulk. In particular, we identified in our spectroscopical analysis that this
surface resonance is embedded in the bulk continuum with a strong coupling to
the majority bulk states. The resonance behaves very bulk-like, as it extends
over the first six atomic layers of the corresponding (001)-surface. Our study
includes experimental investigations, where the bulk electronic structure as
well as surface-related features have been investigated using spin-resolved
photoelectron spectroscopy (SR-UPS) and for a larger probing depth
spin-integrated high energy x-ray photoemission spectroscopy (HAXPES). The
results are interpreted in comparison with first-principles band structure and
photoemission calculations which consider all relativistic, surface and
high-energy effects properly.",1503.01573v1
2017-12-07,Suppression of electron spin decoherence in Rabi oscillations induced by an inhomogeneous microwave field,"The decay of Rabi oscillations provides direct information about coherence of
electron spins. When observed in EPR experiments, it is often shortened by
spatial inhomogeneity of the microwave field amplitude in a bulk sample. In
order to suppress this undesired loss of coherence, we propose an additional
dressing of spin states by a weak longitudinal continuous radiofrequency field.
Our calculations of the Rabi oscillations between the doubly dressed spin
states show that the maximum suppression of decoherence is achieved at the
so-called Rabi resonance when the radio-field frequency is in resonance with
the Rabi frequency of spins in the microwave field. This effect is feasible
even in the absence of phase matching in the radiofrequency field and for
different types of inhomogeneity of the microwave field. The manifestations of
such suppression in the published EPR experiments with the bichromatic driving
are discussed. The realization of the Rabi resonance using the radiofrequency
field could open new possibilities for separating the contributions of
relaxation mechanisms from those due to the inhomogeneous driving in spin
decoherence.",1712.02597v3
2021-02-10,Quantum spin state selectivity and magnetic tuning of ultracold chemical reactions of triplet alkali-metal dimers with alkali-metal atoms,"We demonstrate that it is possible to efficiently control ultracold chemical
reactions of alkali-metal atoms colliding with open-shell alkali-metal dimers
in their metastable triplet states by choosing the internal hyperfine and
rovibrational states of the reactants as well as by inducing magnetic Feshbach
resonances with an external magnetic field. We base these conclusions on
coupled-channel statistical calculations that include the effects of hyperfine
contact and magnetic-field-induced Zeeman interactions on ultracold chemical
reactions of hyperfine-resolved ground-state Na and the triplet
NaLi(a$^3\Sigma^+$) producing singlet Na$_2$($^1\Sigma^+_g$) and a Li atom. We
find that the reaction rates are sensitive to the initial hyperfine states of
the reactants. The chemical reaction of fully spin-polarized, high-spin states
of rotationless NaLi(a$^3\Sigma^+, v = 0, N = 0$) molecules with fully
spin-polarized Na is suppressed by a factor of 10-100 compared to that of
unpolarized reactants. We interpret these findings within the adiabatic state
model, which treats the reaction as a sequence of nonadiabatic transitions
between the initial non-reactive high-spin state and the final low-spin states
of the reaction complex. In addition, we show that magnetic Feshbach resonances
can similarly change reaction rate coefficients by several orders of magnitude.
Some of these resonances are due to resonant trimer bound states dissociating
to the $N=2$ rotational state of NaLi(a$^3\Sigma^+, v = 0$) and would thus
exist in systems without hyperfine interactions.",2102.05707v2
2022-06-27,Optical readout of singlet fission biexcitons with photoluminescence detected magnetic resonance,"Molecular spin systems based on photoexcited triplet pairs formed via singlet
fission (SF) are attractive as carriers of quantum information because of their
potentially pure and controllable spin polarization, but developing systems
that offer optical routes to readout as well as initialization is challenging.
Herein, we characterize the electron spin magnetic resonance change in
photoluminescence intensity for a tailored organic molecular crystal while
sweeping a microwave drive up to 10 GHz in a broadband loop structure. We
observe resonant transitions for both triplet and quintet spin sublevel
populations showing their optical sensitivity, and revealing zero-field
parameters for each. We map the evolution of these spectra in both microwave
frequency and magnetic field, producing a pattern of optically-detected
magnetic resonance (ODMR) peaks. Fits to this data using a suitable model
suggest significant spin polarization in this system with orientation
selectivity. Unusual excitation intensity dependence is also observed, which
inverts the sign of the ODMR signal for triplet features, but not for quintet.
These observations demonstrate optical detection of the spin sublevel
population dictated by SF and intermolecular geometry, and provide unique
insight into the dynamics of triplet pairs.",2206.13636v1
2022-11-22,Magnetic resonance study of rare-earth titanates,"We present a nuclear magnetic resonance (NMR) and electron spin resonance
(ESR) study of rare-earth titanates derived from the spin-1/2 Mott insulator
YTiO$_3$. Measurements of single-crystalline samples of (Y,Ca,La)TiO$_3$ in a
wide range of isovalent substitution (La) and hole doping (Ca) reveal several
unusual features in the paramagnetic state of these materials. $^{89}$Y NMR
demonstrates a clear discrepancy between the static and dynamic local magnetic
susceptibilities, with deviations from Curie-Weiss behavior far above the Curie
temperature $T_C$. No significant changes are observed close to $T_C$, but a
suppression of fluctuations is detected in the NMR spin-lattice relaxation time
at temperatures of about $3\times T_C$. Additionally, the nuclear spin-spin
relaxation rate shows an unusual peak in dependence on temperature for all
samples. ESR of the unpaired Ti electron shows broad resonance lines at all
temperatures and substitution/doping levels, which we find to be caused by
short electronic spin-lattice relaxation times. We model the relaxation as an
Orbach process that involves a low-lying electronic excited state, which
enables the determination of the excited-state gap from the temperature
dependence of the ESR linewidths. We ascribe the small gap to Jahn-Teller
splitting of the two lower Ti $t_{2g}$ orbitals. The value of the gap closely
follows $T_C$ and is consistent with the temperatures at which deviations from
Curie-Weiss fluctuations are observed in NMR. These results provide insight
into the interplay between orbital and spin degrees of freedom in rare-earth
titanates and indicate that full orbital degeneracy lifting is associated with
ferromagnetic order.",2211.12387v2
2016-11-17,Dynamic localization in optical and Zeeman lattices in the presence of spin-orbit coupling,"The dynamic localization of a two-level atom in a periodic potential under
the action of spin-orbit coupling and a weak harmonically-varying linear force
is studied. We consider optical and Zeeman potentials that are either in-phase
or out-of-phase in two spinor components, respectively. The expectation value
for the position of the atom after one oscillation period of the linear force
is recovered in authentic resonances or in pseudo-resonances. The frequencies
of the linear force corresponding to authentic resonances are determined by the
band structure of the periodic potential and are affected by the spin-orbit
coupling. The width/dispersion of the wavepacket in authentic resonances is
usually minimal. The frequencies corresponding to pseudo-resonances do not
depend on the type of potential and on the strength of the spin-orbit coupling,
while the evolution of excitations at the corresponding frequencies is usually
accompanied by significant dispersion. Pseudo-resonances are determined by the
initial phase of the linear force and by the quasi-momentum of the wavepacket.
Due to the spinor nature of the system, the motion of the atom is accompanied
by periodic, but not harmonic, spin oscillations. Under the action of
spin-orbit coupling the oscillations of the wavepacket can be nearly completely
suppressed in optical lattices. Dynamic localization in Zeeman lattices is
characterized by doubling of the resonant oscillation periods due to band
crossing at the boundary of the Brillouin zone. We also show that higher
harmonics in the Fourier expansion of the energy band lead to effective
dispersion, which can be strong enough to prevent dynamic localization of the
Bloch wavepacket.",1611.05745v1
2004-12-23,Quasiperiodic spin-orbit motion and spin tunes in storage rings,"We present an in-depth analysis of the concept of spin precession frequency
for integrable orbital motion in storage rings. Spin motion on the periodic
closed orbit of a storage ring can be analyzed in terms of the Floquet theorem
for equations of motion with periodic parameters and a spin precession
frequency emerges in a Floquet exponent as an additional frequency of the
system. To define a spin precession frequency on nonperiodic synchro-betatron
orbits we exploit the important concept of quasiperiodicity. This allows a
generalization of the Floquet theorem so that a spin precession frequency can
be defined in this case too. This frequency appears in a Floquet-like exponent
as an additional frequency in the system in analogy with the case of motion on
the closed orbit. These circumstances lead naturally to the definition of the
uniform precession rate and a definition of spin tune. A spin tune is a uniform
precession rate obtained when certain conditions are fulfilled. Having defined
spin tune we define spin-orbit resonance on synchro--betatron orbits and
examine its consequences. We give conditions for the existence of uniform
precession rates and spin tunes (e.g. where small divisors are controlled by
applying a Diophantine condition) and illustrate the various aspects of our
description with several examples. The formalism also suggests the use of
spectral analysis to ``measure'' spin tune during computer simulations of spin
motion on synchro-betatron orbits.",0412157v1
2006-10-13,Observation of Faraday rotation from a single confined spin,"Ability to read-out the state of a single confined spin lies at the heart of
solid-state quantum information processing. While all-optical spin measurements
using Faraday rotation has been successfully implemented in ensembles of
semiconductor spins, read-out of a single semiconductor spin has only been
achieved using transport measurements based on spin-charge conversion. Here, we
demonstrate an all-optical dispersive measurement of the spin-state of a single
electron trapped in a semiconductor quantum dot. We obtain information on the
spin state through conditional Faraday rotation of a spectrally detuned optical
field, induced by the polarization- and spin-selective trion (charged quantum
dot) transitions. To assess the sensitivity of the technique, we use an
independent resonant laser for spin-state preparation. An all-optical
dispersive measurement on single spins has the important advantage of
channeling the measurement back-action onto a conjugate observable, thereby
allowing for repetitive or continuous quantum nondemolition (QND) read-out of
the spin-state. We infer from our results that there are of order unity
back-action induced spin-flip Raman scattering events within our measurement
timescale. Therefore, straightforward improvements such as the use of a
solid-immersion lens and higher efficiency detectors would allow for
back-action evading spin measurements, without the need for a cavity.",0610110v1
2010-08-12,"Semiconductor Spin Noise Spectroscopy: Fundamentals, Accomplishments, and Challenges","Semiconductor spin noise spectroscopy (SNS) has emerged as a unique
experimental tool that utilizes spin fluctuations to provide profound insight
into undisturbed spin dynamics in doped semiconductors and semiconductor
nanostructures. The technique maps ever present stochastic spin polarization of
free and localized carriers at thermal equilibrium via the Faraday effect onto
the light polarization of an off-resonant probe laser and was transferred from
atom optics to semiconductor physics in 2005. The inimitable advantage of spin
noise spectroscopy to all other probes of semiconductor spin dynamics lies in
the fact that in principle no energy has to be dissipated in the sample, i.e.,
SNS exclusively yields the intrinsic, undisturbed spin dynamics and promises
optical non-demolition spin measurements for prospective solid state based
optical spin quantum information devices. SNS is especially suitable for small
electron ensembles as the relative noise increases with decreasing number of
electrons. In this review, we first introduce the basic principles of SNS and
the difference in spin noise of donor bound and of delocalized conduction band
electrons. We continue the introduction by discussing the spectral shape of
spin noise and prospects of spin noise as a quantum interface between light and
matter. In the main part, we give a short overview about spin relaxation in
semiconductors and summarize corresponding experiments employing SNS. Finally,
we give in-depth insight into the experimental aspects and discuss possible
applications of SNS.",1008.2191v2
2016-07-13,Dynamics of Stellar Spin Driven by Planets Undergoing Lidov-Kozai Migration: Paths to Spin-Orbit Misalignment,"Many exoplanetary systems containing hot Jupiters (HJs) exhibit significant
misalignment between the spin axes of the host stars and the orbital angular
momentum axes of the planets (""spin-orbit misalignment""). High-eccentricity
migration involving Lidov-Kozai oscillations of the planet's orbit induced by a
distant perturber is a possible channel for producing such misaligned HJ
systems. Previous works have shown that the dynamical evolution of the stellar
spin axis during the high-$e$ migration plays a dominant role in generating the
observed spin-orbit misalignment. Numerical studies have also revealed various
patterns of the evolution of the stellar spin axis leading to the final
misalignment. Here we develop an analytic theory to elucidate the evolution of
spin-orbit misalignment during the Lidov-Kozai migration of planets in stellar
binaries. Secular spin-orbit resonances play a key role in the misalignment
evolution. We include the effects of short-range forces and tidal dissipation,
and categorize the different possible paths to spin-orbit misalignment as a
function of various physical parameters (e.g. planet mass and stellar rotation
period). We identify five distinct spin-orbit evolution paths and outcomes,
only two of which are capable of producing retrograde orbits. We show that
these paths to misalignment and the outcomes depend only on two dimensionless
parameters, which compare the stellar spin precession frequency with the rate
of change of the planet's orbital axis, and the Lidov-Kozai oscillation
frequency. Our analysis reveals a number of novel phenomena for the stellar
spin evolution, ranging from bifurcation, adiabatic advection, to fully chaotic
evolution of spin-orbit angles.",1607.03937v1
2016-10-30,Boson-mediated quantum spin simulators in transverse fields: XY model and spin-boson entanglement,"The coupling of spins to long-wavelength bosonic modes is a prominent means
to engineer long-range spin-spin interactions, and has been realized in a
variety of platforms, such as atoms in optical cavities and trapped ions. To
date, much of the experimental focus has been on the realization of long-range
Ising models, but generalizations to other spin models are highly desirable. In
this work, we explore a previously unappreciated connection between the
realization of an XY model by off-resonant driving of single sideband of boson
excitation (i.e.~a single-beam M{\o}lmer-S{\o}rensen scheme) and a
boson-mediated Ising simulator in the presence of a transverse field. In
particular, we show that these two schemes have the same effective Hamiltonian
in suitably defined rotating frames, and analyze the emergent effective XY spin
model through truncated Magnus series and numerical simulations. In addition to
XY spin-spin interactions that can be non-perturbatively renormalized from the
naive Ising spin-spin coupling constants, we find an effective transverse field
that is dependent on the thermal energy of the bosons, as well as other
spin-boson couplings that cause spin-boson entanglement not to vanish at any
time. In the case of a boson-mediated Ising simulator with transverse field, we
discuss the crossover from transverse-field Ising-like to XY-like spin behavior
as a function of field strength.",1610.09699v1
2023-01-16,Crystal orientation dependent spin pumping in Bi0.1Y2.9Fe5O12/Pt interface,"Ferromagnetic resonance (FMR) based spin pumping is a versatile tool to
quantify the spin mixing conductance and spin to charge conversion (S2CC)
efficiency of ferromagnet/normal metal (FM/NM) heterostructure. The spin mixing
conductance of FM/NM interface can also be tuned by the crystal orientation
symmetry of epitaxial FM. In this work, we study the S2CC in epitaxial Bismuth
substituted Yttrium Iron Garnet (Bi0.1Y2.9Fe5O12) thin films Bi-YIG (100 nm)
interfaced with heavy metal platinum (Pt (8 nm)) deposited by pulsed laser
deposition process on different crystal orientation Gd3Ga5O12 (GGG) substrates
i.e. [100] and [111]. The crystal structure and surface roughness characterized
by X-Ray diffraction and atomic force microscopy measurements establish
epitaxial Bi-YIG[100], Bi-YIG[111] orientations and atomically flat surfaces
respectively. The S2CC quantification has been realized by two complimentary
techniques, (i) FMR-based spin pumping and inverse spin Hall effect (ISHE) at
GHz frequency and (ii) temperature dependent spin Seebeck measurements.
FMR-ISHE results demonstrate that the [111] oriented Bi-YIG/Pt sample shows
significantly higher values of spin mixing conductance ((2.31+-0.23)x10^18
m^-2) and spin Hall angle (0.01+-0.001) as compared to the [100] oriented
Bi-YIG/Pt. A longitudinal spin Seebeck measurement reveals that the [111]
oriented sample has higher spin Seebeck coefficient (106.40+-10 nV mm-1 K-1).
This anisotropic nature of spin mixing conductance and spin Seebeck coefficient
in [111] and [100] orientation has been discussed using the magnetic
environment elongation along the surface normal or parallel to the growth
direction. Our results aid in understanding the role of crystal orientation
symmetry in S2CC based spintronics devices.",2301.06477v1
2003-07-14,Numerical analysis of solitary waves interaction in nonlinear medium,"Using numerical modeling investigated interaction of solitary waves
(solitons) of the regularized long wave equation. For reception the stable
model of the nonlinear medium are used methods of the linear prediction and
progressive approximation. By modeling was determined that depending on ratio
of velocities of the solitons and the form of highest derivatives balance is
possible self-organization of the medium nonequilibrium state as formation of
shock waves and stable on the form solitary waves, created as a result of full
or partial mutual penetration of the solitons. Is possible also aggregation of
the solitons in third wave. The shock waves can pass into other possible
resonance state as a wave front with stable amplitude, which precedes
developing in singularity negative front.",0307023v1
2008-03-05,The Secular Evolution of a Close Ring-Satellite System: The Excitation of Spiral Density Waves at a Nearby Gap Edge,"The Lagrange planetary equations are used to study to secular evolution of a
small, eccentric satellite that orbits within a narrow gap in a broad,
self-gravitating planetary ring. These equations show that the satellite's
secular perturbations of the ring will excite a very long-wavelength spiral
density wave that propagates away from the gap's outer edge. The amplitude of
these waves, as well as their dispersion relation, are derived here. That
dispersion relation reveals that a planetary ring can sustain two types of
density waves: long waves that, in Saturn's A ring, would have wavelengths of
order 100 km, and short waves that tend to be very nonlinear and are expected
to quickly damp. The excitation of these waves also transports angular momentum
from the ring to the satellite in a way that damps the satellite's eccentricity
e, which also tends to reduce the amplitude of subsequent waves. The rate of
eccentricity damping due to this wave action is then compared to the rates at
which the satellite's Lindblad and corotation resonances alter the satellite's
e. These results are then applied to the gap-embedded Saturnian satellites Pan
and Daphnis, and the long-term stability of their eccentricities is assessed.",0803.0576v1
2011-11-29,Cross-waves induced by the vertical oscillation of a fully immersed vertical plate,"Capillary waves excited by the vertical oscillations of a thin elongated
plate below an air-water interface are analyzed using time-resolved
measurements of the surface topography. A parametric instability is observed
above a well defined acceleration threshold, resulting in a so-called
cross-wave, a staggered wave pattern localized near the wavemaker and
oscillating at half the forcing frequency. This cross-wave, which is stationary
along the wavemaker but propagative away from it, is described as the
superposition of two almost anti-parallel propagating parametric waves making a
small angle of the order of $20^\mathrm{o}$ with the wavemaker edge. This
contrasts with the classical Faraday parametric waves, which are exactly
stationnary because of the homogeneity of the forcing. Our observations suggest
that the selection of the cross-wave angle results from a resonant mechanism
between the two parametric waves and a characteristic length of the surface
deformation above the wavemaker.",1111.6769v2
2013-02-12,Two new standing solitary waves in shallow water,"In this paper, the closed-form analytic solutions of two new Faraday's
standing solitary waves due to the parametric resonance of liquid in a vessel
vibrating vertically with a constant frequency are given for the first time.
Using a model based on the symmetry of wave elevation and the linearized
Boussinesq equation, we gain the closed-form wave elevations of the two kinds
of non-monotonically decaying standing solitary waves with smooth crest and the
even or odd symmetry. All of them have never been reported, to the best of our
knowledge. Besides, they can well explain some experimental phenomena. All of
these are helpful to deepen and enrich our understandings about standing
solitary waves and Faraday's wave.",1302.2714v1
2014-11-26,Universality of Sea Wave Growth and Its Physical Roots,"Modern day studies of wind-driven sea waves are usually focused on wind
forcing rather than on the effect of resonant nonlinear wave interactions. The
authors assume that these effects are dominating and propose a simple
relationship between instant wave steepness and time or fetch of wave
development expressed in wave periods or lengths. This law does not contain
wind speed explicitly and relies upon this asymptotic theory. The validity of
this law is illustrated by results of numerical simulations, in situ
measurements of growing wind seas and wind wave tank experiments. The impact of
the new vision of sea wave physics is discussed in the context of conventional
approaches to wave modeling and forecasting.",1411.7235v1
2016-06-03,Spatial-mode-interaction-induced dispersive-waves and their active tuning in microresonators,"The nonlinear propagation of optical pulses in dielectric waveguides and
resonators provides a laboratory to investigate a wide range of remarkable
interactions. Many of the resulting phenomena find applications in optical
systems. One example is dispersive wave generation, the optical analog of
Cherenkov radiation. These waves have an essential role in fiber spectral
broadeners that are routinely used in spectrocopy and metrology. Dispersive
waves form when a soliton pulse begins to radiate power as a result of
higher-order dispersion. Recently, dispersive wave generation in microcavities
has been reported by phase matching the waves to dissipative Kerr cavity (DKC)
solitons. Here, it is shown that spatial mode interactions within a microcavity
can also be used to induce dispersive waves. These interactions are normally
avoided altogether in DKC soliton generation. The soliton self frequency shift
is also shown to induce fine tuning control of the dispersive wave frequency.
Both this mechanism and spatial mode interactions provide a new method to
spectrally control these important waves.",1606.00954v1
2017-03-24,Turbulence of Weak Gravitational Waves in the Early Universe,"We study the statistical properties of an ensemble of weak gravitational
waves interacting nonlinearly in a flat space-time. We show that the resonant
three-wave interactions are absent and develop a theory for four-wave
interactions in a reduced case of a diagonal metric tensor. In this limit,
where only one type of gravitational waves are present, we derive the
interaction Hamiltonian and consider the asymptotic regime of weak
gravitational wave turbulence. Both direct and inverse cascades are found for
the energy and the wave action respectively, and the corresponding wave spectra
are derived. The inverse cascade is characterized by a finite-time propagation
of the metric excitations - a process similar to an explosive non-equilibrium
Bose-Einstein condensation, which provides an efficient mechanism to ironing
out small-scale inhomogeneities. The direct cascade leads to an accumulation of
the radiation energy in the system. These processes might be important for
understanding the early Universe where a background of weak nonlinear
gravitational waves is expected.",1703.09069v3
2022-07-06,Periodic and solitary wave solutions of the long wave-short wave Yajima-Oikawa-Newell model,"Models describing long wave-short wave resonant interactions have many
physical applications from fluid dynamics to plasma physics. We consider here
the Yajima-Oikawa-Newell (YON) model, which has been recently introduced
combining the interaction terms of two long wave-short wave, integrable models,
one proposed by Yajima-Oikawa, and the other one by Newell. The new YON model
contains two arbitrary coupling constants and it is still integrable - in the
sense of possessing a Lax pair - for any values of these coupling constants. It
reduces to the Yajima-Oikawa or the Newell systems for special choices of these
two parameters. We construct families of periodic and solitary wave solutions,
which display the generation of very long waves. We also compute the explicit
expression of a number of conservation laws.",2207.02499v1
1999-01-29,Excitation of Electromagnetic Wake Fields by one-dimensional Electron Bunch in Plasma in the Presence of Circularly Polarized Intense Electromagnetic Wave,"The excitation of electromagnetic (EM) wake waves in electron plasma by an
one-dimensional bunch of charged particles has been considered in the presence
of intense monochromatic circularly polarized electromagnetic (CPEM) pump wave.
In the zero state (in the absence of bunch) the interaction of the pump wave
with plasma is described by means of Maxwell equations and relativistic
nonlinear hydrodynamic equations of cold plasma. The excitation of linear waves
by one-dimensional bunch is considered on this background. It is shown that
there are three types of solutions of linear equations obtained for induced
waves corresponding to three ranges of parameter values of the pump wave, bunch
and plasma. In the first range of parameter values the amplitude of transverse
components of induced waves is shown to grow as the bunch energy and after some
value of the relativistic factor of the bunch to be almost independent of the
energy and increase proportional to the intensity and frequency of the pump
wave. The dependence of longitudinal component of induced waves on the
relativistic factor of the bunch is weak. Its amplitude and wavelength grow as
the intensity of pump wave. The second range of parameters is a resonance one.
The amplitude of the wave excited by the bunch is a linear function of the
distance to the bunch. In the third range of parameter values the longitudinal
component of induced fields are localized near the bunch boundaries and are
exponentially decreased with the increase in distance from these boundaries.
The amplitudes of transverse components of induced waves reach a constant value
with the distance from the bunch boundaries.",9901059v1
2016-11-16,Global regularity for the 3D finite depth capillary water waves,"In this paper, we prove global regularity, scattering, and the non-existence
of small traveling waves for the $3D$ finite depth capillary waves system for
small initial data. The non-existence of small traveling waves shows a
fundamental difference between the capillary waves ($\sigma=1, g=0$) and the
gravity-capillary waves ($\sigma=1,$ $ 0< g< 3$) in the finite depth setting.
As, for the later case, there exists arbitrary small $L^2$ traveling waves.
  Different from the water waves system in the infinite depth setting, the
quadratic terms of the same system in the finite depth setting are worse due to
the absence of null structure inside the Dirichlet-Neumann operator. In the
finite depth setting, the capillary waves system has the worst quadratic terms
among the water waves systems with all possible values of gravity effect
constant and surface tension coefficient. It loses favorable cancellations not
only in the High $\times$ Low type interaction but also in the High $\times $
High type interaction.
  In the worst scenario, the best decay rate of the nonlinear solution that one
could expect is $ (1+t) ^ {-1/2} $, because the $3D$ finite depth capillary
waves system lacks null structures and there exists $Q(u, \bar{u})$ type
quadratic term, which causes a very large time resonance set and the definite
growth of the associated profile. As a result, the problematic terms are not
only the quadratic terms but also the cubic terms.
  To prove global regularity for the capillary waves system, we identify a good
variable to prove the dispersion estimate, fully exploit the hidden structures
inside the capillary waves system, and use a novel method to control the
weighted norms.",1611.05472v1
2021-09-09,A new integrable model of long wave-short wave interaction and linear stability spectra,"We consider the propagation of short waves which generate waves of much
longer (infinite) wave-length. Model equations of such long wave-short wave
resonant interaction, including integrable ones, are well-known and have
received much attention because of their appearance in various physical
contexts, particularly fluid dynamics and plasma physics. Here we introduce a
new long wave-short wave integrable model which generalises those first
proposed by Yajima-Oikawa and by Newell. By means of its associated Lax pair,
we carry out the linear stability analysis of its continuous wave solutions by
introducing the stability spectrum as an algebraic curve in the complex plane.
This is done starting from the construction of the eigenfunctions of the
linearised long wave-short wave model equations. The geometrical features of
this spectrum are related to the stability/instability properties of the
solution under scrutiny. Stability spectra for the plane wave solutions are
fully classified in the parameter space together with types of modulational
instabilities.",2109.04296v1
1992-12-14,Spin-Wave Theory and Finite-Size Scaling for the Heisenberg Antiferromagnet,"Spin-wave perturbation theory for the Heisenberg antiferromagnet at zero
temperature is used to compute the finite-lattice corrections to the ground
state energy, the staggered magnetization and the energy gap. The dispersion
relation, the spin-wave velocity and the bulk ground state energy to order
$O(1/S^2)$ are also computed for the square lattice. The results agree very
well with the predictions of Neuberger and Ziman and Fisher.",9212020v1
1995-02-10,The influence of structure disorder on mean atomic momentum fluctuations and a spin-wave spectrum,"The relation between atomic momenta fluctuations and density fluctuations is
obtained in frames of mean-field approximation. Using two-time temperature
Green functions within Tyablikov approximation the equations for spin
excitation energy and damping are obtained. The asymptotics of energy and
damping in the long-wave limit are investigated and the anomalous behaviour of
spin-wave stiffness constant is discussed.",9502042v1
1996-07-24,Long Wavelength Anomalous Diffusion Mode in the 2D XY Dipole Magnet,"In 2D XY ferromagnet the dipole force induces a strong interaction between
spin-waves in the long-wavelength limit. The major effect of this interaction
is the transformation of a propagating spin-wave into a diffusion mode. We
study the anomalous dynamics of such diffusion modes. We find that the
Janssen-De Dominics functional, which governs this dynamics, approaches the
non-Gaussian fixed-point. A spin-wave propagates by an anomalous anisotropic
diffusion with the dispersion relation: $i\omega{\sim}k_{y}^{\Delta_y}$ and
$i\omega{\sim}k_{x}^{\Delta_x}$, where ${\Delta_y}=47/27$ and
${\Delta_x}=47/36$. The low-frequency response to the external magnetic field
is found.",9607168v1
1997-03-02,On the Self-Consistent Spin-Wave Theory of Two-Dimensional Magnets With Impurities,"The self-consistent spin-wave theory is applied to investigate the
magnetization distribution around the impurity in isotropic and easy-axis
two-dimensional ferro- and antiferromagents. The temperature dependences of
host magnetization disturbance and impurity magnetization are calculated. The
short-range order in the isotropic case is investigated. Importance of dynamic
and kinematic interactions of spin waves is demonstrated.",9703010v1
1999-05-24,Temperature behavior of the magnon modes of the square lattice antiferromagnet,"A spin-wave theory of short-range order in the square lattice Heisenberg
antiferromagnet is formulated. With growing temperature from T=0 a gapless mode
is shown to arise simultaneously with opening a gap in the conventional
spin-wave mode. The spectral intensity is redistributed from the latter mode to
the former. For low temperatures the theory reproduces results of the modified
spin-wave theory by M.Takahashi, J.E.Hirsch et al. and without fitting
parameters gives values of observables in good agreement with Monte Carlo
results in the temperature range 0 <= T < 0.8J where J is the exchange
constant.",9905340v1
1999-11-23,New Spin-Wave Mode in Weak Ferromagnetic Fermi Liquids,"We study a phenomenological model for weak ferromagnetic Fermi liquids and
investigate the properties of the spin waves in the model. The Landau kinetic
equation is used to derive, in addition to the known Goldstone mode, a new
spin-wave mode -- the first Silin-like ferromagnetic mode. We discuss the role
of the interaction parameter F^a_1 on the behavior of the Goldstone mode and
the first Silin-like ferromagnetic mode.",9911363v1
2000-05-29,Orbital-ordering-induced anomalous softening of the ferromagnetic spin waves in perovskite manganites,"Spin wave excitations were measured in the ferromagnetic phase of
Nd$_{1/2}$Sr$_{1/2}$MnO$_{3}$ by neutron scattering. This compound is located
in proximity to the A-type antiferromagnetic state, and it shows a clear
anisotropy and anomalous softening of the spin wave excitations. The softening
in the ferromagnetic phase is induced by the orbital ordering.",0005497v2
2002-10-18,Spin-Wave Description of Haldane-gap antiferromagnets,"Modifying the conventional antiferromagnetic spin-wave theory which is
plagued by the difficulty of the zero-field sublattice magnetizations diverging
in one dimension, we describe magnetic properties of Haldane-gap
antiferromagnets. The modified spin waves, constituting a grand canonical
bosonic ensemble so as to recover the sublattice symmetry, not only depict well
the ground-state correlations but also give useful information on the
finite-temperature properties.",0210399v3
2003-03-20,About possible Phonon to Magnon alignment in 2 dimensions and theory of superconductivity in Copper-Oxide planes,"We suggest that the phonon dispersion in cuprates becomes strongly
anisotropic due to interaction with spin waves; moreover the phonon dispersion
becomes singular along $|k_x|=|k_y|$ directions. This would allow more
electrons to form Cooper pairs and increase temperature of the superconducting
transition. The interaction of phonons with spin waves is more important than
the interaction of phonons with free electrons, because spin waves do not have
the Fermi surface constrain.",0303402v5
2003-03-22,A long-wave action of spin Hamiltonians and the inverse problem of the calculus of variations,"We suggest a method of derivation of the long-wave action of the model spin
Hamiltonians using the non-linear partial differential equations of motions of
the individual spins. According to the Vainberg's theorem the set of these
equations are (formal) potential if the symmetry analysis for the Frechet
derivatives of the system is true. The case of Heisenberg (anti)ferromagnets is
considered. It is shown the functional whose stationary points are described by
the equations coincides with the long-wave action and includes the non-trivial
topological term (Berry phase).",0303479v1
2004-04-03,Electromagnetic analog of Rashba spin-orbit interaction in wave guides filled with ferrite,"We consider infinitely long electromagnetic wave guide filled with a ferrite.
The wave guide has arbitrary but constant cross-section $. We show that Maxwell
equations are equivalent to the Schr\""odinger equation for single electron in
the two-dimensional quantum dot of the form D with account of the Rashba
spin-orbit interaction. The spin-orbit constant is determining by components of
magnetic permeability of the ferrite. The upper component of electron spinor
function corresponds to the z-th component electric field, while the down
component $\chi$ related to the z-th component of magnetic field by relation
(30).",0404072v1
2004-07-29,Field-induced spin density wave in (TMTSF)$_2$NO$_3$,"Interlayer magnetoresistance of the Bechgaard salt (TMTSF)$_2$NO$_3$ is
investigated up to 50 teslas under pressures of a few kilobars. This compound,
the Fermi surface of which is quasi two-dimensional at low temperature, is a
semi metal under pressure. Nevertheless, a field-induced spin density wave is
evidenced at 8.5 kbar above $\sim$ 20 T. This state is characterized by a
drastically different spectrum of the quantum oscillations compared to the low
pressure spin density wave state.",0407764v2
2004-09-17,Solitary waves on finite-size antiferromagnetic quantum Heisenberg spin rings,"Motivated by the successful synthesis of several molecular quantum spin rings
we are investigating whether such systems can host magnetic solitary waves. The
small size of these spin systems forbids the application of a classical or
continuum limit. We therefore investigate whether the time-dependent
Schroedinger equation itself permits solitary waves. Example solutions are
obtained via complete diagonalization of the underlying Heisenberg Hamiltonian.",0409456v3
2005-08-30,Current induced transverse spin-wave instability in thin ferromagnets: beyond linear stability analysis,"A sufficiently large unpolarized current can cause a spin-wave instability in
thin nanomagnets with asymmetric contacts. The dynamics beyond the instability
is understood in the perturbative regime of small spin-wave amplitudes, as well
as by numerically solving a discretized model. In the absence of an applied
magnetic field, our numerical simulations reveal a hierarchy of instabilities,
leading to chaotic magnetization dynamics for the largest current densities we
consider.",0508732v1
2005-11-11,Magnonics: Experiment to Prove the Concept,"An experimental scheme for studying spin wave propagation across thin film
samples is proposed. An experiment upon a periodically layered nanowire is
numerically simulated, while the sample might equally well be a continuous film
or an array of elements (e.g. nanowires) that either have uniform composition
or are periodically layered as in a magnonic crystal. The experiments could be
extended to study domain wall induced spin wave phase shifts, and used for
creation of the spin wave magnetic logic devices.",0511290v1
2005-11-11,Spin wave spectrum of a magnonic crystal with an isolated defect,"Real magnonic crystals - periodic magnetic media for spin wave (magnon)
propagation - may contain some defects. We report theoretical spin wave spectra
of a one dimensional magnonic crystal with an isolated defect. The latter is
modeled by insertion of an additional layer with thickness and magnetic
anisotropy values different from those of the magnonic crystal constituent
layers. The defect layer leads to appearance of several localized defect modes
within the magnonic band gaps. The frequency and the number of the defect modes
may be controlled by varying parameters of the constituent layers of the
magnonic crystal.",0511295v1
2006-11-30,Theory of Brillouin Light Scattering from Ferromagnetic Nanospheres,"We develop the theory of Brillouin light scattering (BLS) from spin wave
modes in ferromagnetic nanospheres, within a framework that incorporates the
spatial variation of the optical fields within the sphere. Our recent theory of
exchange dipole spin wave modes of the sphere provides us with eigenvectors.
When properly normalized, these eigenvectors allow calculation of the absolute
cross section of various modes which contribute to BLS spectrum. We then
present explicit calculation of the BLS spectrum associated with the first few
dipole/exchange spin wave modes with emphasis on their relative intensity.",0611785v1
1993-05-18,Spin Structure of the Pion in a Light-Cone Representation,"The spin structure of the pion is discussed by transforming the wave function
for the pion in the naive quark model into a light-cone representation. It is
shown that there are higher helicity ($\lambda_{1}+\lambda_{2}=\pm1$) states in
the full light-cone wave function for the pion besides the ordinary helicity
($\lambda_{1}+\lambda_{2}=0$) component wave functions as a consequence from
the Melosh rotation relating spin states in light-front dynamics and those in
instant-form dynamics. Some low energy properties of the pion, such as the
electromagnetic form factor, the charged mean square radius, and the weak decay
constant, could be interrelated in this representation with reasonable
parameters.",9305283v1
2004-12-18,Relativistic wave equations for interacting massive particles with arbitrary half-intreger spins,"New formulation of relativistic wave equations (RWE) for massive particles
with arbitrary half-integer spins s interacting with external electromagnetic
fields are proposed. They are based on wave functions which are irreducible
tensors of rank $n ($n=s-\frac12$) antisymmetric w.r.t. n pairs of indices,
whose components are bispinors. The form of RWE is straightforward and free of
inconsistencies associated with the other approaches to equations describing
interacting higher spin particles.",0412213v1
2006-05-16,Detection of Gravitational Wave - An Application of Relativistic Quantum Information Theory,"We show that a passing gravitational wave may influence the spin entropy and
spin negativity of a system of $N$ massive spin-1/2 particles, in a way that is
characteristic of the radiation. We establish the specific conditions under
which this effect may be nonzero. The change in spin entropy and negativity,
however, is extremely small. Here, we propose and show that this effect may be
amplified through entanglement swapping. Relativistic quantum information
theory may have a contribution towards the detection of gravitational wave.",0605135v1
2007-11-05,Projected p-wave superconducting wave-functions for topological orders,"In this paper we develop a sysmatical theory for topological orders by the
projected p-wave superconducting (SC) wave-functions and unify the different
topological orders for spin models into the fermionic picture. We found that
the energy for the fermions at k=(0,0), (0, pi), (pi, 0), (pi, pi) acts as a
topological invariable to characterize 16 universal classes of different
topological orders for the spin models with translation invariance. Based on
the projected p-wave SC wave-functions the topological properties for the known
topological orders in the exact solved spin models are obtained. Finally new
types of topological orders are predicted.",0711.0571v1
2007-12-07,The Hartree-Fock ground state of the three-dimensional electron gas,"In 1962, Overhauser showed that within Hartree-Fock (HF) the electron gas is
unstable to a spin density wave (SDW) instability. Determining the true HF
ground state has remained a challenge. Using numerical calculations for finite
systems and analytic techniques, we study the HF ground state of the 3D
electron gas. At high density, we find broken spin symmetry states with a
nearly constant charge density. Unlike previously discussed spin wave states,
the observed wave vector of the SDW is smaller than $2 k_F$. The
broken-symmetry state originates from pairing instabilities at the Fermi
surface, a model for which is proposed.",0712.1194v1
2008-02-21,Coherent Control of spin-orbit precession with shaped laser pulses,"Spin precession in Rubidium atoms is investigated through a pump-probe
technique. The excited wave packet corresponds to a precession of spin and
orbital angular momentum around the total angular momentum. We show that using
shaped laser pulses allows us to control this dynamics. With a Fourier
transform limited pulse, the wave packet is initially prepared in the bright
state (coupled to the initial state) whereas a pulse presenting a $\pi $ step
in the spectral phase prepares the wave packet in the dark state (uncoupled to
the initial state).",0802.2986v1
2008-04-14,Dissipation characteristics of quantized spin waves in nano-scaled magnetic ring structures,"The spatial profiles and the dissipation characteristics of spin-wave
quasi-eigenmodes are investigated in small magnetic Ni$_{81}$Fe$_{19}$ ring
structures using Brillouin light scattering microscopy. It is found, that the
decay constant of a mode decreases with increasing mode frequency. Indications
for a contribution of three-magnon processes to the dissipation of higher-order
spin-wave quasi-eigenmodes are found.",0804.2200v1
2008-05-27,Scattering of backward spin waves in a one-dimensional magnonic crystal,"Scattering of backward volume magnetostatic spin waves from a one-dimensional
magnonic crystal, realized by a grating of shallow grooves etched into the
surface of an yttrium-iron garnet film, was experimentally studied. Rejection
frequency bands were clearly observed. The rejection efficiency and the
frequency width of the rejection bands increase with increasing groove depth. A
theoretical model based on the analogy of a spin-wave film-waveguide with a
microwave transmission line was used to interpret the obtained experimental
results.",0805.4142v1
2008-11-21,Frequency-dependent reflection of spin waves from a magnetic inhomogeneity induced by a surface DC-current,"The reflectivity of a highly localized magnetic inhomogeneity is
experimentally studied. The inhomogeneity is created by a dc-current carrying
wire placed on the surface of a ferrite film. The reflection of propagating
dipole-dominated spin-wave pulses is found to be strongly dependent on the
spin-wave frequency if the current locally increases the magnetic field. In the
opposite case the frequency dependence is negligible.",0811.3491v1
2009-01-13,Refractive index and Snell's Law for Dipolar-Exchange Spin-Waves in a Confined Planar Structure,"We derived the analytical forms of refractive index and Snell law for
dipolar-exchange spin waves of reflection and refraction at a magnetically
heterogeneous interface in a geometrically confined planer structure composed
of different magnetic thin films from a microscopic scattering approach. A
novel behavior, the optical total reflection, was demonstrated for spin waves
with a specific interface between Yttrium iron garnet (Y3Fe5O12) and Permalloy
(Ni80Fe20), by analytical and micromagnetic numerical calculations.",0901.1700v2
2009-12-25,A linearized spin-wave theory for thermodynamics of quantum Heisenberg antiferromagnet on a square lattice,"The thermodynamics of the quantum Heisenberg antiferromagnet on a square
lattice is revisited through a linearized spin-wave theory which is well
defined at any finite temperature. We re-examine in details the temperature
dependence of the free energy, the internal energy, the entropy and the
specific heat. Most conclusions of the thermodynamics in previous studies can
be reproduced in our linearized spin-wave theory. Specially, our calculation at
low temperature $T<J$ agrees quantitatively with the numerical Quantum Monte
Carlo simulation and high temperature series expansions.",0912.4965v1
2010-07-25,Optical excitation of nonlinear spin waves,"We demonstrate a technique for exciting spin waves in an ultracold gas of
Rb-87 atoms based on tunable AC Stark potentials. This technique allows us to
excite normal modes of spin waves with arbitrary amplitudes in the trapped gas,
including dipole, quadrupole, octupole, and hexadecapole modes. These modes
exhibit strong nonlinearities, which manifest as amplitude dependence of the
excitation frequencies and departure from sinusoidal behavior. Our results are
in good agreement with a full treatment of a quantum Boltzmann transport
equation.",1007.4339v2
2011-04-19,Chaotic Spin-Wave Solitons in Magnetic Film Feedback Rings,"Chaotic spin-wave solitons in magnetic film active feedback rings were
observed for the first time. At some ring gain level, one observes the
self-generation of a single spin-wave soliton pulse in the ring. When the pulse
circulates in the ring, its amplitude varies chaotically with time. Numerical
simulations based on a gain-loss nonlinear Schr\""odinger equation reproduce the
observed responses.",1104.3871v1
2011-08-22,Spin Density Wave in Insulating Ferromagnetic Frustrated Chain LiCuVO$_4$,"We study field induced quantum phase in weakly-coupled ferromagnetic
frustrated chain LiCuVO$_4$ by neutron diffraction technique. A new
incommensurate magnetic peak is observed at $H \ge 8.5$ T. The field dependent
propagation vector is identified with the spin density wave correlation in the
theoretically predicted magnetic quadrupole order. Quantum fluctuation,
geometrical frustration, and interchain interaction induce the exotic spin
density wave long-range order in the insulating magnet.",1108.4255v1
2011-09-09,Theoretical Investigation of the Magnetic Order in FeAs,"The magnetic structure of the iron monoarsenide FeAs is studied using
first-principles calculations. We consider the collinear and non-collinear
(spin-spiral wave) magnetic ordering and magnetic anisotropy. It is
analitically shown that a magnetic triaxial anisotropy results in a sum of two
spin-spiral waves with opposite directions of wave vectors and different spin
amplitudes, so that the magnetic moments in two perpendicular directions do not
equal each other.",1109.1924v1
2011-12-07,"Retrieval of multiple spin waves from a weakly excited, metastable atomic ensemble","The emission of light from a multiply excited atomic ensemble is examined and
it is shown how symmetric (spin-wave) and non-symmetric states of excitation
radiate into spatially separate field modes. This observation has potential
application to single photon generation and spin wave entanglement, since in
the presence of atomic interactions it can result in isolated single photon
emission into a phase-matched field mode.",1112.1735v2
2012-01-31,Generation of Multipartite Continuous-variable Entanglements via Atomic Spin Wave,"We present a proof-of-principle way to generate nondegenerate multipartite
continuous-variable entanglements via atomic spin wave induced by the strong
coupling and probe fields in the Lambda-type electromagnetically induced
transparency configuration in an atomic ensemble. Quantum
correlated/anti-correlated and entangled Stokes and anti-Stokes fields,
simultaneously produced through scattering the applied laser fields off the
atomic spin wave, can be achieved. This method can, in principle, be extended
to flexibly and conveniently create multicolor multipartite entangled
narrow-band fields to any desired order with long correlation time, which may
find promising applications in quantum information processing and quantum
networks.",1201.6577v1
2012-05-11,Magnetic penetration depth in the presence of a spin-density wave in multiband superconductors at zero temperature,"We present a theoretical description of the London penetration depth of a
multi-band superconductor in the case when both superconducting and
spin-density wave orders coexist. We focus on clean systems and zero
temperature to emphasize the effect of the two competing orders. Our
calculation shows that the supefluid density closely follows the evolution of
the superconducting order parameter as doping is increased, saturating to a BCS
value in the pure superconducting state. Furthermore, we predict a strong
anisotropic in-pane penetration depth induced by the spin-density wave order.",1205.2564v1
2012-05-25,Spin wave amplification driven by heat flow: the role of damping and exchange interaction,"In this article we report on micromagnetic simulations performed on a
permalloy nanostructure in presence of a uniform thermal gradient. Our
numerical simulations show that heat flow is an effective mean to compensate
the damping, and that the gradients at which spin-wave amplification is
observed are experimentally accessible. In particular, we have studied the role
of the Gilbert damping parameter on spin-wave amplification.",1205.5650v2
2013-11-12,Nonreciprocity engineering in magnetostatic spin waves,"Magnetostatic surface spin waves (MSSW) excited from a coplanar waveguide
antenna travel in different directions with different amplitudes. This effect,
called nonreciprocity of MSSW, has been investigated by micromagnetic
simulations. The ratio of amplitude of two counter propagating spin waves, the
nonreciprocity parameter {\kappa}, is obtained for different ferromagnetic
materials, such as NiFe (Py), CoFeAl, yttrium iron garnet (YIG), and GaMnAs. A
device schematic has been proposed in which {\kappa} can be tuned to a large
value by varying simple geometrical parameters of the device.",1311.2686v1
2014-11-10,Magnon spectrum in ferromagnets with a skyrmion,"The analysis of the spin wave excitations in two-dimensional isotropic
Heisenberg ferromagnet is performed with a single skyrmion in the ground state.
We employ the ideas of semiclassical quantization method, duly modified for the
use of the lattice model and Maleyev-Dyson boson representation of spin
operators. The resulting Schr\""odinger equation for magnons describes the
dispersion and wave functions of spin-wave excitations with strictly
non-negative spectrum. In contrast to usual ferromagnet, we demonstrate the
existence of three zero modes, corresponding to conformal symmetries
spontaneously violated by the skyrmion configuration.",1411.2452v2
2014-12-19,Spin waves in one-dimensional bi-component quasicrystals,"We studied finite Fibonacci sequence of Co and Py stripes aligned
side-by-side and in direct contact with each other. Calculations based on
continuous model including exchange and dipole interactions were performed for
structures feasible for fabrication and characterization of main properties of
magnonic quasicrystals. We have shown the fractal structure of the magnonic
spectrum with a number of magnonics gaps of different width. Also localization
of spin waves in quasicrystals and existence of surface spin waves in finite
quaiscrystal structure is demonstrated.",1412.6301v4
2015-01-06,Spin Wave Diffraction Control and Read-out with a Quantum Memory for Light,"A scheme for control and read-out of diffracted spins waves to propagating
light fields is presented. Diffraction is obtained via sinusoidally varying
lights shifts and ideal one-to-one mapping to light is realized using a
gradient echo quantum memory. We also show that dynamical control of the
diffracted spin waves spatial orders can be implemented to realize a quantum
pulse sequencer for temporal modes that have high time-bandwidth products. Full
numerical solutions suggest that both co-propagating and couterpropagating
light shift geometries can be used, making the proposal applicable to hot and
cold atomic vapours as well as solid state systems with two-level atoms.",1501.01194v1
2015-03-16,Detection of spin waves in permalloy using planar Hall effect,"Rectification of microwave oscillations of magnetization in a permalloy film
is realized using planar Hall effect. Two different rectified signals are
obtained: a signal from the linearly excited uniform magnetization precession
at the frequency of the external pumping and a signal from the pairs of
contra-propagating short-wavelength spin waves parametrically generated at a
half of the pumping frequency. The second, most unusual, rectified signal is
caused by the uniform component of the dynamic magnetization created due to the
interference of the phase correlated pairs of parametric spin waves.",1503.04638v1
2015-11-30,Study of the Spin-weighted Spheroidal Wave Equation in the Case of s=3/2,"In this paper, we use the means of super-symmetric quantum mechanics to study
of the Spin-weighted Spheroidal Wave in the case of s=3/2. We obtain some
interesting results: the first-five terms of the super-potential, the general
form of the super-potential. The ground eigen-function and eigenvalue of the
equation are also given. According these results, we make use of the shape
invariance property to compute the exited eigenvalues and eigen-functions.
These results help us to understand the Spin-weighted Spheroidal Wave and show
that it is integral.",1512.00514v1
2016-01-04,Direct and inverse cascades of spin-wave turbulence in spin-1 ferromagnetic spinor Bose-Einstein condensates,"We theoretically and numerically study spin-wave turbulence in spin-1
ferromagnetic spinor Bose-Einstein condensates, finding direct and inverse
cascades with power-law behavior. To derive these power exponents analytically,
the conventional weak wave turbulence theory is applied to the spin-1 spinor
Gross-Pitaevskii equation. Thus, we obtain the $-7/3$ and $-5/3$ power laws in
the transverse spin correlation function for the direct and inverse cascades,
respectively. To confirm these power laws, numerical calculations are performed
that obtain results consistent with these power laws.",1601.00446v2
2016-04-25,Bias-free spin-wave phase shifter for magnonic logic,"A design of a magnonic phase shifter operating without an external bias
magnetic field is proposed. The phase shifter uses a localized collective spin
wave mode propagating along a domain wall ""waveguide"" in a dipolarly-coupled
magnetic dot array existing in a chessboard antiferromagnetic (CAFM) ground
state. It is demonstrated numerically that remagnetization of a single magnetic
dot adjacent to the domain wall waveguide introduces a controllable phase shift
in the propagating spin wave mode without significant change of the mode
amplitude. It is also demonstrated that a logic XOR gate can be realized in the
same system.",1604.07337v1
2016-06-27,Spin wave power flow and caustics in ultrathin ferromagnets with the Dzyaloshinskii-Moriya interaction,"The Dzyaloshinskii-Moriya interaction in ultrathin ferromagnets can result in
nonreciprocal propagation of spin waves. We examine theoretically how spin wave
power flow is influenced by this interaction. We show that the combination of
the dipole-dipole and Dzyaloshinskii-Moriya interactions can result in
unidirectional caustic beams in the Damon-Eshbach geometry. Morever,
self-generated interface patterns can also be induced from a point-source
excitation.",1606.08159v2
2018-06-20,Influence of quadratic Zeeman effect on spin waves in dipolar lattices,"A lattice of particles with dipolar magnetic moments is considered under the
presence of quadratic Zeeman effect. Two types of this effect are taken into
account, the effect due to an external nonresonant magnetic field and the
effect caused by an alternating quasiresonance electromagnetic field. The
presence of the alternating-field quadratic Zeeman effect makes it possible to
efficiently vary the sample characteristics. The main attention is payed to the
study of spin waves whose properties depend on the quadratic Zeeman effect. By
varying the quadratic Zeeman-effect parameter it is possible to either suppress
or stabilize spin waves.",1806.07607v1
2012-09-06,Excitation modes of vortices in sub-micron magnetic disks,"Classical and quantum theory of spin waves in the vortex state of a
mesoscopic sub-micron magnetic disk has been developed with account of the
finite mass density of the vortex. Oscillations of the vortex core resemble
oscillations of a charged string in a potential well in the presence of the
magnetic field. Conventional gyroscopic frequency appears as a gap in the
spectrum of spin waves of the vortex. The mass of the vortex has been computed
that agrees with experimental findings. Finite vortex mass generates a
high-frequency branch of spin waves. Effects of the external magnetic field and
dissipation have been addressed.",1209.1375v1
2019-06-24,Graded index lenses for spin wave steering,"We use micromagnetic modelling to demonstrate the operation of graded index
lenses designed to steer forward-volume magnetostatic spin waves by 90 and 180
degrees. The graded index profiles require the refractive index to diverge in
the lens center, which, for spin waves, can be achieved by modulating the
saturation magnetization or external magnetic field in a ferromagnetic film by
a small amount. We also show how the 90$^\circ$ lens may be used as a beam
divider. Finally, we analyse the robustness of the lenses to deviations from
their ideal profiles.",1906.09985v1
2021-02-23,Fast acquisition of spin-wave dispersion by compressed sensing,"For the realization of magnonic devices, spin-wave dispersions need to be
identified. Recently, the time-resolved pump-probe imaging method combined with
the Fourier transform was demonstrated for obtaining the dispersions in the
lower-wavenumber regime. However, the measurement takes a long time when the
sampling rate is sufficiently high. Here, we demonstrated the fast acquisition
of spin-wave dispersions by using the compressed sensing technique. Further, we
quantitatively evaluated the consistency of the results. Our results can be
applied to other various pump-probe measurements, such as observations based on
the electro-optical effects.",2102.11626v1
2021-04-19,A Thesaurus for Common Priors in Gravitational-Wave Astronomy,"In gravitational-wave data analysis, we regularly work with a host of
non-trivial prior probabilities on compact binary masses, redshifts, and spins.
We must regularly manipulate these priors, computing the implied priors on a
transformed basis of parameters or reweighting posterior samples from one prior
to another. Here, I detail some common manipulations, presenting a table of
Jacobians with which to transform priors between mass parametrizations,
describing the conversion between source- and detector-frame priors, and
deriving analytic expressions for priors on the ""effective spin"" parameters
regularly invoked in gravitational-wave astronomy.",2104.09508v1
2019-04-19,How does the photon's spin affect Gravitational Wave measurements?,"We study the effect of the polarization of light beams on the time delay
measured in Gravitational Wave experiments. To this end, we consider the
Mathisson-Papapetrou-Dixon equations in a gravitational wave background, with
two of the possible spin supplementary conditions: by Frenkel-Pirani, or by
Tulczyjew. In the first case, photons follow a null geodesic and thus no spin
effect is present. The second case shows a deviation of the photons from the
null geodesic, resulting in a tiny effect on the measured time delay of photons
depending on their polarization state.",1904.09260v2
2020-05-12,Analysis in k-space of Magnetization Dynamics Driven by Strong Terahertz Fields,"Demagnetization in a thin film due to a terahertz pulse of magnetic field is
investigated. Linearized LLG equation in the Fourier space to describe the
magnetization dynamics is derived, and spin waves time evolution is studied.
Finally, the demagnetization due to spin waves dynamics and recent experimental
observations on similar magnetic system are compared. As a result of it, the
marginal role of spin waves dynamics in loss of magnetization is established.",2005.05742v1
2020-05-26,Spoken digit classification using a spin-wave delay-line active-ring reservoir computing,"As a test of general applicability, we use the recently proposed spin-wave
delay line active-ring reservoir computer to perform the spoken digit
recognition task. On this, classification accuracies of up to 93% are achieved.
The tested device prototype employs improved spin wave transducers (antennas).
Therefore, in addition, we also let the computer complete the short-term memory
(STM) task and the parity check (PC) tasks, because the fading memory and
nonlinearity are essential to reservoir computing performance. The resulting
STM and PC capacities reach maximum values of 4.77 and 1.47 respectively.",2005.12557v1
2020-07-15,Spin wave theory of one-dimensional generalized Kitaev model,"In this work, we perform a combination of classical and spin wave analysis on
the one-dimensional spin-$S$ Kitaev-Heisenberg-Gamma model in the region of an
antiferromagnetic Kitaev coupling. Four phases are found, including a N\'eel
ordered phase, a phase with $O_h\rightarrow D_3$ symmetry breaking, and
""$D_3$-breaking I, II"" phases which both break $D_3$ symmetries albeit in
different ways, where $O_h$ is the full octahedral group and $D_3$ is the
dihedral group of order six. The lowest-lying spin wave mass is calculated
perturbatively in the vicinity of the hidden SU(2) symmetric ferromagnetic
point.",2007.07509v1
2006-11-29,Wave Modes in the Magnetospheres of Pulsars and Magnetars,"We study the wave propagation modes in the relativistic streaming pair plasma
of the magnetospheres of pulsars and magnetars, focusing on the effect of
vacuum polarization. We show that the combined plasma and vacuum polarization
effects give rise to a vacuum resonance, where ``avoided mode crossing'' occurs
between the extraordinary mode and the (superluminous) ordinary mode. When a
photon propagates from the vacuum-polarization-dominated region at small radii
to the plasma-dominated region at large radii, its polarization state may
undergo significant change across the vacuum resonance. We map out the
parameter regimes (e.g., field strength, plasma density and Lorentz factor)
under which the vacuum resonance occurs and examine how wave propagation is
affected by the resonance. Some possible applications of our results are
discussed, including high-frequency radio emission from pulsars and possibly
magnetars, and optical/IR emission from neutron star surfaces and inner
magnetospheres.",0611924v2
2005-11-12,Universal properties of modulated antiferromagnetic systems,"Magnetism and superconductivity are physical phenomena whose foundations are
rooted in quantum mechanics and whose technological applications do not cease
to surprise us. In this article we describe a class of magnetic materials, we
call modulated antiferromagnetic systems (MAS), that has a prominent
representative in the copper-oxide high-temperature superconductors. The class,
however, is not exclusive to these superconductors. Indeed, several materials
that belong to that class are insulators. The magnetic spectral weight of MAS
displays the following universal properties: a local intensity maximum
(resonance peak) at the commensurate antiferromagnetic wave vector; peaks at
the nearly-antiferromagnetic wave vectors for excitation energies well below
the resonance, and at wave vectors rotated by 45 degrees for energies above
resonance. Moreover, we predict an observable rotation by 45 degrees of the
peaks immediately below the resonance. All these universal signatures,
condensed in a twisted hour-glass-like spectrum, are merely consequences of the
unique topological characteristics of the single-particle magnetic dispersion
relation. We thus provide a unifying scenario that explains the phenomenology
that has been observed in inelastic neutron scattering experiments of the
high-temperature superconductors.",0511303v1
2003-12-05,The Mario Schenberg Gravitational Wave Detector: A mathematical model for its quadrupolar oscilations,"In this work we present a mathematical model for the mechanical response of
the Brazilian Mario SCHENBERG gravitational wave (GW) detector to such waves.
We found the physical parameters that are involved in this response assuming a
linear elastic theory. Adopting this approach we determined the system's
resonance frequencies for the case when six $i$-mode mechanical resonators are
coupled to the antenna surface according to the arrangement suggested by
Johnson and Merkowitz: the truncated icosahedron configuration. This
configuration presents special symmetries that allow for the derivation of an
analytic expression for the mode channels, which can be experimentally
monitored and which are directly related to the tensorial components of the GW.
Using this model we simulated how the system behaves under a gravitational
sinewave quadrupolar force and found the relative amplitudes that result from
this excitation. The mechanical resonators made the signal $\approx 5340$ times
stronger. We found $i+1$ degenerate triplets plus $i$ non-degenerate system
mode resonances within a band around ${3.17-3.24\rm{kHz}}$ that are sensitive
to signals higher than ${\tilde h\sim 10^{-22}\rm{Hz}^{-1/2}}$ when we
considerate the effects of thermal noise only.",0312035v1
2002-08-23,Resonant Absorption between Moving Atoms due to Doppler Frequency Shift and Quantum Energy Variation,"By taking both the Doppler frequency shift for electromagnetic wave and the
quantum energy variation of matter wave into consideration, a
resonant-absorption condition based on the local-ether wave equation is
presented to account for a variety of phenomena consistently, including the
Ives-Stilwell experiment, the output frequency from ammonia masers, and the
M\""{o}ssbauer rotor experiment. It is found that in the resonant-absorption
condition, the major term associated with the laboratory velocity is a
dot-product term between this velocity and that of the emitting or absorbing
atom. This term appears both in the Doppler frequency shift and the transition
frequency variation and then cancels out. Thereby, the experimental results can
be independent of the laboratory velocity and hence comply with Galilean
relativity, despite the restriction that the involved velocities are referred
specifically to the local-ether frame. However, by examining the
resonant-absorption condition in the M\""{o}ssbauer rotor experiment to a higher
order, it is found that Galilean relativity breaks down.",0208084v1
2004-09-03,Nonlinear cyclotron-resonance accelerations by a generalized EM wave,"Particle accelerations by a 1D, EM, dispersive pulse in an external magnetic
field are investigated. It is found that the well-known cyclotron resonance may
be classified into three regimes as the length and/or the amplitude of the
pulse are varied. Namely, as the pulse amplitude increases, the transit-time
cyclotron-resonance acceleration [CRA] evolves to phase trapping, and reflect
particles. The amplitude and wave dispersion as well as the pulse length
strongly affect those accelerations. The interesting phenomena of quantization
of resonance velocities in between the two regimes are also investigated. This
new mechanism may lead to wave amplification at some discrete frequencies other
than the cyclotron frequency.",0409025v1
2004-10-13,Enhanced Doppler Effect in the Upper Hybrid Resonance Microwave Backscattering Experiment,"Observations of enhanced Doppler frequency shift effect of the highly
localized microwave backscattering in the upper hybrid resonance are reported.
The experiment is performed at FT-2 tokamak, where a steerable focusing antenna
set, allowing off equatorial plane plasma extraordinary wave probing from high
magnetic field side, was installed. A separate line less than 1.5 MHz wide and
shifted by up to 2 MHz is routinely observed in the backscattering spectrum
under condition of accessible upper hybrid resonance. The enhanced frequency
shift is explained by the growth of poloidal wave number of the probing wave in
the resonance. The new scheme for local diagnostics of fluctuations poloidal
rotation based on this effect is proposed.",0410081v1
2005-09-05,Rigorous analysis of grazing-angle scattering of electromagnetic waves in periodic gratings,"Grazing-angle scattering (GAS) is a type of Bragg scattering of waves in
slanted non-uniform periodic gratings, when the diffracted order satisfying the
Bragg condition propagates at a grazing angle with respect to the boundaries of
a slab-like grating. Rigorous analysis of GAS of bulk TE electromagnetic waves
is undertaken in holographic gratings by means of the enhanced T-matrix
algorithm. A comparison of the rigorous and the previously developed
approximate theories of GAS is carried out. A complex pattern of numerous
previously unknown resonances is discovered and analysed in detail for gratings
with large amplitude, for which the approximate theory fails. These resonances
are associated not only with the geometry of GAS, but are also typical for wide
transmitting gratings. Their dependence on grating amplitude, angles of
incidence and scattering, and grating width is investigated numerically.
Physical interpretation of the predicted resonances is linked to the existence
and the resonant generation of special new eigenmodes of slanted gratings. Main
properties of these modes and their field structure are discussed.",0509040v1
2008-03-12,Case study: calculation of a narrow resonance with the LIT method,"The possibility to resolve narrow structures in reaction cross sections in
calculations with the Lorentz integral transform (LIT) method is studied. To
this end we consider a fictitious two-nucleon problem with a low-lying and
narrow resonance in the $^3P_1$ nucleon-nucleon partial wave and calculate the
corresponding ``deuteron photoabsorption cross section''. In the LIT method the
use of continuum wave functions is avoided and one works instead with a
localized function \tilde\Psi. In this case study it is investigated how far
into the asymptotic region \tilde\Psi has to be determined in order to obtain a
precise resolution of the artificially introduced E1 resonance. Comparing with
the results of a conventional calculation with explicit neutron-proton
continuum wave functions it is shown that the LIT approach leads to an
excellent reproduction of the cross section in the resonance region and of
further finer cross section details at higher energies. To this end, however,
for \tilde\Psi one has to take into account two-nucleon distances up to at
least 30 fm.",0803.1770v1
2012-03-11,Dynamical Systems' approach to relativistic nonlinear wave-particle interaction in weakly collisional plasmas,"In this report, we present a dynamical systems' approach to study the exact
nonlinear wave-particle interaction in relativistic regime. We give a
particular attention to the effect of wave obliquity on the dynamics of the
orbits by studying the specific cases of parallel ($\theta=0$) and
perpendicular ($\theta=-\pi/2$) propagations in comparison to the general case
of oblique propagation $\theta=]-\pi/2, 0[$. We found that the fixed points of
the system correspond to Landau resonance, and that the dynamics can evolve
from trapping to surfatron acceleration for propagation angles obeying a Hopf
bifurcations condition. Cyclotron-resonant particles are also studied by the
construction of a pseudo-potential structure in the Lorentz factor $\gamma$. We
derived a condition for which Arnold diffusion results in relativistic
stochastic acceleration. Hence, two general conclusions are drawn : 1) The
propagation angle $\theta$ can significantly alter the dynamics of the orbits
at both Landau and cyclotron-resonances. 2) Considering the short-time scales
upon which the particles are accelerated, these two mechanisms for Landau and
cyclotron resonant orbits could become potential candidates for problems of
particle energization in weakly collisional space and cosmic plasmas.",1203.2302v1
2012-05-24,Theory of ultrafast autoionization dynamics of Fano resonances,"We study atomic autoionization processes in the time domain. With the
emerging attosecond extreme vacuum ultraviolet and soft x-ray pulses, we first
address how to characterize the time evolution of the decay of a discrete state
into a degenerate continuum. A short pump beam generates a number of resonance
states in a series and the nearby background continuum, and the resultant wave
packet evolves with time until the full decay of the bound states. Taking the
2pns(^1P^o) resonance series embedded in the 2sEp(^1P^o) continuum in beryllium
atom as an example, the time evolution of the autoionizing wave packet in
energy domain and in coordinate space is calculated and analyzed, where Fano
profiles build up in the photoelectron energy during the process. A proposed
pump-probe scheme assumes that the probe beam ionizes the 2s inner electron in
the wave packet. The lifetimes of the resonances and the photoelectron energy
distribution can be obtained from the ionization yield versus the time delay of
the probe.",1205.5476v1
2014-09-11,Superdimensional Metamaterial Resonators,"We propose a fundamentally new method for the design of metamaterial arrays,
valid for any waves modeled by the Helmholtz equation, including scalar optics
and acoustics. The design and analysis of these devices is based on eigenvalue
and eigenfunction asymptotics of solutions to Schr\""odinger wave equations with
harmonic and degenerate potentials. These resonators behave superdimensionally,
with a higher local density of eigenvalues and greater concentration of waves
than expected from the physical dimension, e.g., planar resonators function as
3- or higher-dimensional media, and bulk material as effectively of dimension 4
or higher. Applications include antennas with a high density of resonant
frequencies and giant focussing, and are potentially broadband.",1409.3608v1
2014-11-27,Ratchet effect enhanced by plasmons,"Ratchet effect -- a {\it dc} current induced by the electromagnetic wave
impinging on the spatially modulated two-dimensional (2D) electron liquid --
occurs when the wave amplitude is spatially modulated with the same wave vector
as the 2D liquid but is shifted in phase. The analysis within the framework of
the hydrodynamic model shows that the ratchet current is dramatically enhanced
in the vicinity of the plasmonic resonances and has nontrivial polarization
dependence. In particular, for circular polarization, the current component,
perpendicular to the modulation direction, changes sign with the inversion of
the radiation helicity. Remarkably, in the high-mobility structures, this
component might be much larger than the the current component in the modulation
direction. We also discuss the non-resonant regime realized in dirty systems,
where the plasma resonances are suppressed, and demonstrate that the
non-resonant ratchet current is controlled by the Maxwell relaxation in the 2D
liquid.",1411.7436v1
2016-02-08,Detection and imaging of microcracking in complex media using coda wave interferometry (CWI) under linear resonance conditions,"This letter presents the development of ultrasonic coda wave interferometry
to locate and image microcracks created within consolidated granular media,
polymer concrete. Results show that microcracks can be detected through coda
waves when the polymer concrete is submitted to a linear resonance. In
addition, the multiple scattering revealed to be dependent on the plane in
which the resonance is excited. In that sense, Acoustic emission measurements
were performed under flexural resonances generated in (XY) and (XZ) planes to
verify the existence of a possible structural anisotropy related to
microcracks. Recorded acoustic signatures revealed important differences in the
frequency contents, depending on the considered plane, with a consequent wealth
on the involved mechanisms during the microcracks vibrations.",1602.02510v1
2017-08-07,Resonant absorption of electromagnetic waves in transition anisotropic media,"We study the mode conversion and resonant absorption phenomena occurring in a
slab of a stratified anisotropic medium, optical axes of which are tilted with
respect to the direction of inhomogeneity, using the invariant imbedding theory
of wave propagation. When the tilt angle is zero, mode conversion occurs if the
longitudinal component of the permittivity tensor, which is the one in the
direction of inhomogeneity in the non-tilted case, varies from positive to
negative values within the medium, while the transverse component plays no
role. When the tilt angle is nonzero, the wave transmission and absorption show
an asymmetry under the sign change of the incident angle in a range of the tilt
angle, while the reflection is always symmetric. We calculate the reflectance,
the transmittance and the absorptance for several configurations of the
permittivity tensor and find that resonant absorption is greatly enhanced when
the medium from the incident surface to the resonance region is hyperbolic than
when it is elliptic. For certain configurations, the transmittance and
absorptance curves display sharp peaks at some incident angles determined by
the tilt angle.",1708.02020v2
2017-09-03,Non-reciprocal Optical Mirrors Based on Spatio-Temporal Modulation,"The recent surge of interest in temporal modulation schemes to induce
magnet-free non-reciprocity has inspired several exciting opportunities for
photonic technology. Here, we investigate a scheme to realize free-space
isolators and highly non-reciprocal mirrors with weak modulation imparted by an
acoustic wave. Conventional optical mirrors are reciprocal: in a given plane of
incidence, reflection is independent of the sign of the angle of incidence,
which enables two people to simultaneously look at each other through their
reflection. In contrast, we propose a strategy to dramatically break this
symmetry by exploiting resonant interactions between a travelling acoustic wave
and highly resonant guided optical modes, inducing total reflection of an
optical beam at a given angle, and no reflection at the negative angle.
Different from conventional acousto-optic isolators, which are based on
non-resonant frequency conversion and filtering, our proposal operates at the
frequency of the optical signal by tailoring the resonant properties of the
structure as well as the acoustic wave frequency and intensity, enabling 50 dB
isolation with modest modulation requirements. Operation in reflection allows
for close-to-zero insertion loss, enabling disruptive opportunities in our
ability to control and manipulate photons.",1709.00702v1
2018-10-11,Unexpected Thermal Conductivity Enhancement in Pillared Graphene Nanoribbon with Isotopic Resonance,"Thermal transport in nanoribbon based nanostructures is critical to advancing
its applications. Wave effects of phonons can give rise to controllability of
heat conduction in nanostructures beyond that by particle scattering. In this
paper, by introducing pillars to form structural resonance, we systematically
studied the thermal conductivity of graphene nanoribbon based phononic
metamaterials (GNPM) through non-equilibrium molecular dynamical simulation.
Interestingly, it is found that the thermal conductivity of GNPM is counter
intuitively enhanced by isotope engineering, which is strong contrast to the
common notion that isotope engineering reduces thermal conductivity.Further
mode analysis and atomic Green function calculation reveal that the unexpected
increasing in thermal conductivity originates from the breaking of the resonant
hybridization wave effect between the resonant modes and the propagating modes
induced by isotope engineering. Besides, factors including the system width and
pillar height can also efficiently tune the thermal conductivity of GNPM. This
abnormal mechanism provides a new dimension to manipulate phonon transport in
nanoribbon based nanostructures through wave effect.",1810.04841v2
2018-02-13,High Quality Factor Surface Fabry-Perot Cavity of Acoustic Waves,"Surface acoustic wave (SAW) resonators are critical components in wireless
communications and many sensing applications. They have also recently emerged
as subject of study in quantum acoustics at the single phonon level. Acoustic
loss reduction and mode confinement are key performance factors in SAW
resonators. Here we report the design and experimental realization of a high
quality factor Fabry-Perot SAW resonators formed in between tapered phononic
crystal mirrors patterned on a GaN-on-sapphire material platform . The
fabricated SAW resonators are characterized by both electrical network analyzer
and optical heterodyne vibrometer. We observed standing Rayleigh wave inside
the cavity, with an intrinsic quality factor exceeding 13,000 at ambient
conditions.",1802.04788v1
2020-08-26,Direct Imaging of Resonant Phonon-Magnon Coupling,"Direct detection of phonons is important for the investigation of information
interconversion between the resonantly coupled magnons and phonons. Here we
report resonant coupling of magnons and phonons, which can be directly
visualized by using micro focused Brillouin light scattering in Ni/LiNbO3
hybrid heterostructures. The patterns of surface acoustic wave phonons,
originating from the interference between the original wave {\psi}0(A_0,k) and
reflected wave {\psi}1(A_1,-k), can be modulated by magnetic field due to the
magnon-phonon coupling. By analyzing the information of phonons obtained from
Brillouin spectroscopy, the properties of the magnon system (Ni film), e.g.,
ferromagnetic resonance field and resonance linewidth can be determined. The
results provide spatially resolved information about phonon manipulation and
detection in a coupled magnon-phonon system.",2008.11391v2
2017-10-03,On the wave dispersion and non-reciprocal power flow in space-time traveling acoustic metamaterials,"This note analytically investigates non-reciprocal wave dispersion in locally
resonant acoustic metamaterials. Dispersion relations associated with
space-time varying modulations of inertial and stiffness parameters of the base
material and the resonant components are derived. It is shown that the
resultant dispersion bias onsets intriguing features culminating in a break-up
of both acoustic and optic propagation modes and one-way local resonance band
gaps. The derived band structures are validated using the full transient
displacement response of a finite metamaterial. A mathematical framework is
presented to characterize power flow in the modulated acoustic metamaterials to
quantify energy transmission patterns associated with the non-reciprocal
response. Since local resonance band gaps are size-independent and frequency
tunable, the outcome enables the synthesis of a new class of sub-wavelength
low-frequency one-way wave guides.",1710.03689v2
2019-03-15,Non-Scattering Multi-Mirror Systems for Field Localization,"Resonators composed of two mirrors, such as Fabry-Perot cavities, provide a
simple but effective approach to achieve wave transmission with high finesse.
Further increase of the quality factor requires reflectors with higher
conductivity or multi-mirror solutions. However, the analytical complexity of
resonators with more than two mirrors prevents the design of optimal structures
without recurring to numerical methods. This work considers an alternative
approach to this problem by using cavities which do not produce any
electromagnetic scattering. We demonstrate that these invisible cavities can be
placed inside one another, resulting in a `matryoshka-doll'-like resonator. The
standing-wave distribution of the inner resonator can be controlled without
disturbing that of the outer one, whereas the whole system remains
non-scattering.",1903.06483v1
2019-05-29,Surface phonon polariton resonance imaging using long-wave infrared-visible sum-frequency generation microscopy,"We experimentally demonstrate long-wave infrared-visible sum-frequency
generation microscopy for imaging polaritonic resonances of infrared (IR)
nanophotonic structures. This nonlinear-optical approach provides direct access
to the resonant field enhancement of the polaritonic near fields, while the
spatial resolution is limited by the wavelength of the visible sum-frequency
signal. As a proof-of-concept, we here study periodic arrays of
subdiffractional nanostructures made of 4H-silicon carbide supporting localized
surface phonon polaritons. By spatially scanning tightly focused incident
beams, we observe excellent sensitivity of the sum-frequency signal to the
resonant polaritonic field enhancement, with a much improved spatial resolution
determined by visible laser focal size. However, we report that the tight
focusing can also induce sample damage, ultimately limiting the achievable
resolution with the scanning probe method. As a perspective approach towards
overcoming this limitation, we discuss the concept of using wide-field
sum-frequency generation microscopy as a universal experimental tool that would
offer long-wave IR super-resolution microscopy with spatial resolution far
below the IR diffraction limit.",1905.12499v1
2020-11-18,Triadic resonances driven by thermal convection in a rotating sphere,"We report for the first time on triadic resonances in a rotating convection
system. Using direct numerical simulations, we find that convective modes in a
rotating spherical fluid can excite a pair of inertial modes whose frequencies
and wavenumbers match the triadic resonance conditions. Depending on the
structures of the convective modes, triadic resonances can lead to the growth
of either a pair of modes with lower frequencies and wavenumbers, or a pair of
modes with higher frequencies and wavenumbers, providing a possible mechanism
for the bi-directional energy cascade. Increased thermal forcing leads to fully
developed turbulence, which also exhibits wave-like motions, and is reminiscent
of the energy spectrum of inertial wave turbulence. Our results suggest that
the interaction of inertial waves plays an important role in rotating
convection, which is of great importance in understanding the dynamics of
planetary and stellar interiors.",2011.09151v2
2020-11-24,Learning the structure of giant resonances from their $γ$-decay,"The direct $\gamma$-decays of the giant dipole resonance (GDR) and the giant
quadrupole resonance (GQR) of $^{208}$Pb to low-lying states are investigated
by means of a microscopic self-consistent model. The model considers effects
beyond the linear response approximation. The strong sensitivity of
$\gamma$-decay to the isospin of the involved states is proven. By comparing
their decay widths, a much larger weight of the $3_{1}^{-}$ component in the
GQR wave function of $^{208}$Pb is deduced, with respect to the weight of the
$2_{1}^{+}$ component in the GDR wave function. Thus, we have shown that
$\gamma$-decay is a unique probe of the resonance wave functions, and a
testground for nuclear structure models.",2011.11943v1
2020-01-20,Resonance scattering in a waveguide with identical thick barriers,"We consider wave propagation across an infinite waveguide of an arbitrary
bounded cross-section, whose interior is blocked by two identical thick
barriers with holes. When the holes are small, the waves over a broad range of
frequencies are almost fully reflected. However, we show the existence of a
resonance frequency at which the wave is almost fully transmitted, even for
very small holes. This resonance scattering, which is known as tunneling effect
in quantum mechanics, is demonstrated in a constructive way by rather
elementary tools, in contrast to commonly used abstract methods such as
searching for complex-valued poles of the scattering matrix or non-stationary
scattering theory. In particular, we derived an explicit equation that
determines the resonance frequency. The employed elementary tools make the
paper accessible to non-experts and educationally appealing.",2001.07060v1
2020-05-28,Extreme quantum nonlinearity in superfluid thin-film surface waves,"We show that highly confined superfluid films are extremely nonlinear
mechanical resonators, offering the prospect to realize a mechanical qubit.
Specifically, we consider third-sound surface waves, with nonlinearities
introduced by the van der Waals interaction with the substrate. Confining these
waves to a disk, we derive analytic expressions for the cubic and quartic
nonlinearities and determine the resonance frequency shifts they introduce. We
predict single-phonon shifts that are three orders of magnitude larger than in
current state-of-the-art nonlinear resonators. Combined with the exquisitely
low intrinsic dissipation of superfluid helium and the strongly suppressed
acoustic radiation loss in phononic crystal cavities, we predict that this
could allow blockade interactions between phonons as well as
two-level-system-like behavior. Our work provides a new pathway towards extreme
mechanical nonlinearities, and towards quantum devices that use mechanical
resonators as qubits.",2005.13919v2
2020-05-29,"Semicylindrical microresonator: excitation, modal structure, and Q factor","The semicylindrical microresonator with relatively simple excitation with a
plane wave is studied. The resonator is formed on the base of the
dielectric/metal/dielectric structure, where the wave energy penetrates into
resonator through a thin metal layer and stored in a semicylindrical dielectric
with high permittivity. The proposed microresonator combines features of
Fabry-Perot and Whispering gallery mode resonators. Dependence of radiation
losses on the radius and materials are estimated by theoretical analysis, while
excitation by a plane wave is shown via numerical analysis. The quality
Q-factor of the resonator can achieve up to 104, at a radius of a semicylinder
of several microns.",2005.14527v1
2020-12-29,Impact of Band Structure on Wave Function Dissipation in Field Emission Resonance,"We demonstrated on Ag(111) and Ag(100) surfaces that the reciprocal of the
field emission resonance (FER) linewidth, which is proportional to the mean
lifetime of resonant electrons in FER, may vary with the electric field. The
variation on Ag(111) was nearly smooth, whereas that on Ag(100) was sporadic
and fluctuated remarkably. This drastic difference can be explained through
their dissimilar projected bulk band structures and the ensemble interpretation
of quantum mechanics, according to which all resonant electrons are governed by
a single wave function. Ag(100) has an energy gap above its vacuum level,
whereas Ag(111) does not. Consequently, the dissipation rate of the wave
function, which is relevant to the FER linewidth, on Ag(111) was almost stable,
whereas that on Ag(100) fluctuated. The fluctuation revealed that the quantum
trapping effect and surface dipole layer on Ag(100) surface can be investigated
through FER.",2012.14646v1
2022-02-13,Approximating transmission and reflection spectra near isolated nondegenerate resonances,"A linear scattering problem for which incoming and outgoing waves are
restricted to a finite number of radiation channels can be precisely described
by a frequency-dependent scattering matrix. The entries of the scattering
matrix, as functions of the frequency, give rise to the transmission and
reflection spectra. To find the scattering matrix rigorously, it is necessary
to solve numerically the partial differential equations governing the relevant
waves. In this paper, we consider resonant structures with an isolated
nondegenerate resonant mode of complex frequency $\omega_\star$, and show that
for real frequencies near $\omega_0 = \mbox{Re}(\omega_\star)$, the
transmission and reflection spectra can be approximated using only the
scattering matrix at $\omega_0$ and information about the resonant mode. We
also present a revised temporal coupled-mode theory that produces the same
approximate formulas for the transmission and reflection spectra. Numerical
examples for diffraction of plane waves by periodic structures are presented to
validate our theory.",2202.06324v1
2022-09-14,Relativistic Topological Waves from Cherenkov and Doppler Resonances in Self-Magnetized Laser Plasmas,"Strong magnetic fields at plasma-plasma interfaces can be naturally produced
in laser-plasma interactions. Using theoretical analysis and fully
three-dimensional particle-in-cell simulations, we demonstrate that
relativistic topological waves can be generated via Cherenkov and Doppler
resonances in the interaction of intense femtosecond laser pulses with
near-critical-density plasmas. At the self-magnetized plasma-plasma interface,
a new slow-wave branch appears. Its phase velocity is much smaller than the
group velocity of the laser pulse and the electron beam velocity. Therefore,
the Cherenkov resonance condition can be easily satisfied. Furthermore, since
electrons undergo betatron oscillations, Doppler resonances may also occur and
are responsible for the excitation of several frequency-shifted branches
observed in our simulations. After the passage of the laser pulse, we observe a
fast remnant mode with relativistic amplitude and frequency close to the local
plasma frequency. This mode continues to accelerate electrons further for many
tens of laser periods even after the laser pulse has left the plasma.",2209.06685v1
2022-12-02,Inverse resonance problem for Love seismic surface waves,"In this paper we solve an inverse resonance problem for the half-solid with
vanishing stresses on the surface: Lamb's problem. Using a semi-classical
approach we are able to simplify this three-dimensional problem of the elastic
wave equation for the half-solid as a Schr\""odinger equation with Robin
boundary conditions on the half-line. We obtain asymptotic values on the number
and the location of the resonances with respect to the wave number. Moreover,
we prove that the mapping from real compactly supported potentials to the Jost
functions in a suitable class of entire functions is one-to-one and onto and we
produce an algorithm in order to retrieve the shear modulus from the
eigenvalues and resonances.",2212.01075v2
2022-12-15,Resonant and off-resonant magnetoacoustic waves in epitaxial Fe$_3$Si/GaAs hybrid structures,"Surface acoustic waves (SAWs) provide an efficient dynamical coupling between
strain and magnetization in micro/nano-metric devices. Using a hybrid device
composed of a piezoelectric, GaAs, and a ferromagnetic Heusler alloy thin film,
Fe$_3$Si, we are able to quantify the amplitude of magnetoacoustic waves
generated with SAWs via magnetic imaging in an X-ray photoelectron microscope.
The cubic anisotropy of the sample together with a low damping coefficient
allows for the observation of resonant and non-resonant magnetoelastic
coupling. Additionally, via micromagnetic simulation, we verify the
experimental behavior and quantify the magnetoelastic shear strain component in
Fe$_3$Si that appears to be very large ($b_2=14\times 10^6$ J/m$^3$), much
larger than the one found in Nickel.",2212.07994v1
2023-05-24,Time-reversal Invariance Violation and Quantum Chaos Induced by Magnetization in Ferrite-Loaded Resonators,"We investigate the fluctuation properties in the eigenfrequency spectra of
flat cylindrical microwave cavities that are homogeneously filled with
magnetized ferrite. These studies are motivated by experiments in which only
small pieces of ferrite were embedded in the cavity and magnetized with an
external static magnetic field to induce partial time-reversal (T ) invariance
violation. We use two different shapes of the cavity, one exhibiting an
integrable wave dynamics, the other one a chaotic one. We demonstrate that in
the frequency region where only transverse-magnetic modes exist, the
magnetization of the ferrites has no effect on the wave dynamics and does not
induce T -invariance violation whereas it is fully violated above the cutoff
frequency of the first transverse-electric mode. Above all, independently of
the shape of the resonator, it induces a chaotic wave dynamics in that
frequency range in the sense that for both resonator geometries the spectral
properties coincide with those of quantum systems with a chaotic classical
dynamics and same invariance properties under application of the generalized T
operator associated with the resonator geometry.",2305.14753v1
2024-04-08,A birdcage resonant antenna for helicon wave generation in TORPEX,"A birdcage resonant helicon antenna is designed, mounted and tested in the
toroidal device TORPEX. The birdcage resonant antenna is an alternative to the
usual Boswell or half-helical antenna designs commonly used for $\sim$ 10 cm
diameter helicon sources in low temperature plasma devices. The main advantage
of the birdcage antenna lies in its resonant nature, which makes it easily
operational even at large scales, an appealing feature for the TORPEX device
whose poloidal cross section is 40 cm in diameter. With this antenna helicon
waves are shown to be launched and sustained throughout the whole torus of
TORPEX. The helicon waves can be launched at low power on a pre-existing
magnetron-generated plasma with little effect on the density profiles. The
birdcage antenna can also be used alone to produce plasma, which removes the
constraint of a narrow range of applied magnetic fields required by the
magnetron, opening the way to a new range of studies on TORPEX with the
external magnetic field as a control parameter.",2404.05441v1
2004-10-08,Influence of bounce resonance effects on the cyclotron wave instabilities in dipole magnetospheric plasmas with anisotropic temperature,"In this paper, we derive the dispersion equations for field-aligned cyclotron
waves in an axisymmetric dipole magnetospheric plasmas with both the
bi-Maxwellian and bi-Lorentzian distribution functions. To evaluate the
contribution of trapped particles to the transverse current density components
the Vlasov equation is solved using a standard method of switching to new
variables associated with conservation integrals; new time-like variable is
introduced (instead of the geomagnetic latitude angle) to describe the
bounce-motion of trapped particles along the geomagnetic field; the perturbed
electric field and current density components are Fourier-decomposed over the
length of the geomagnetic field lines. As a result, the transverse permittivity
elements are expressed by summation of bounce-resonant terms including the
double integration in velocity space, the resonant denominators, and the
corresponding phase coefficients. Due to geomagnetic field nonuniformity, the
wave-particle resonance conditions in magnetospheric plasmas are entirely
different from ones in the straight magnetic field; the all spectrum of the
electric field is present in the given current density harmonic; the left- and
right-hand polarized waves are coupled. To have some analogy with the linear
theory of cyclotron waves in the straight magnetic field, we assume that the
n-th harmonic of the electric field gives the main contribution to the n-th
harmonic of the current density, and the connection of the left- and right-hand
polarized waves is small. In this case, the dispersion equations for cyclotron
waves have the simplest form and are suitable to analyze the instabilities of
both the electron- and ion-cyclotron waves accounting for the bounce resonance
effects.",0410059v1
2021-08-13,Kronoseismology V: A Panoply of Waves in Saturn's C Ring Driven by High-Order Internal Planetary Oscillations,"Saturn's rings act as a system of innumerable test particles that are
remarkably sensitive to periodic disturbances in the planet's gravitational
field. We identify 15 additional density and bending waves in Saturn's C ring
driven by the planet's internal normal mode oscillations. Taking advantage of a
highly accurate absolute radius scale for the rings, we are able to detect
weak, high-wavenumber (up to m=14) waves with km-scale radial wavelengths. From
a systematic scan of the entire C ring, we report the discovery and
identification of 11 new Outer Lindblad Resonances (OLRs), two counterpart
inner Lindblad resonances (ILRs), and two new Outer Vertical Resonances (OVRs).
The close agreement of the observed resonance locations and wave rotation rates
with the predictions of models of Saturn's interior suggests that all of the
new waves are driven by Saturnian f-mode oscillations. As classified by their
spherical harmonic shapes, the modes in question range in azimuthal wavenumber
from m=8 to 14, with associated resonance orders l-m ranging from 0 to 8, where
l is the overall angular wavenumber of the mode. Our suite of detections for
l-m=4 is now complete from m=8 to m=14. Curiously, detections with l-m=2 are
less common. These newly-identified non-sectoral waves sample latitudinal as
well as radial structure within the planet and may thus provide valuable
constraints on Saturn's differential rotation. Allowing for the fact that the
two ILR-type waves appear to be due to the same normal modes as two of the
OLR-type waves, the 13 additional modes identified here bring to 34 the number
of distinct f-modes suitable for constraining interior models.",2108.06362v1
2002-03-29,Magnetic Order in YBa$_2$Cu$_3$O$_{6+x}$ Superconductors,"Polarized and unpolarized neutron diffraction has been used to search for
magnetic order in YBa$_2$Cu$_3$O$_{6+x}$ superconductors. Most of the
measurements were made on a high quality crystal of YBa$_2$Cu$_3$O$_{6.6}$. It
is shown that this crystal has highly ordered ortho-II chain order, and a sharp
superconducting transition. Inelastic scattering measurements display a very
clean spin-gap and pseudogap with any intensity at 10 meV being 50 times
smaller than the resonance intensity. The crystal shows a complicated magnetic
order that appears to have three components. A magnetic phase is found at high
temperatures that seems to stem from an impurity with a moment that is in the
$a$-$b$ plane, but disordered on the crystal lattice. A second ordering occurs
near the pseudogap temperature that has a shorter correlation length than the
high temperature phase and a moment direction that is at least partly along the
c-axis of the crystal. Its moment direction, temperature dependence, and Bragg
intensities suggest that it may stem from orbital ordering of the $d$-density
wave (DDW) type. An additional intensity increase occurs below the
superconducting transition. The magnetic intensity in these phases does not
change noticeably in a 7 Tesla magnetic field aligned approximately along the
c-axis. Searches for magnetic order in YBa$_2$Cu$_3$O$_{7}$ show no signal
while a small magnetic intensity is found in YBa$_2$Cu$_3$O$_{6.45}$ that is
consistent with c-axis directed magnetic order. The results are contrasted with
other recent neutron measurements.",0204002v1
2004-03-28,Fully polarized states and decoherence,"The aim of this review is to show how ``ferromagnetic'' states, that is,
states having a fully polarization, can produce intrinsic decoherence by
unitary evolution. This effect can give an understanding of recent experiments
on mesoscopic devices as quantum point contacts showing the 0.7 conductance
anomaly and the wide number of data about saturation of dephasing time observed
at very low temperatures, as a fully polarized two dimensional electron gas.
But similar effects can be seen in different area of physics as for example the
Dicke model describing the interaction of two-level systems with a radiation
mode. In this case one can show that decoherence is intrinsic and remove a
Schr\""odinger cat state leaving a single coherent state, collapsing the wave
function in the thermodynamic limit. So, saturation of dephasing time at low
temperatures in mesoscopic devices can be understood by a fully polarized two
dimensional electron gas that, by an exchange model, can be reduced to a
generalized form of the Dicke Hamiltonian and where the quasiparticles are spin
excitations interacting with magnons. In this way, one can see that several
experiments on nanowires and quantum dots can be satisfactorily explained. The
existence of intrinsic decoherence in the thermodynamic limit could have deep
implications in fundamental problems like quantum measurement and
irreversibility. Recent experiments with cavities with a large number of
photons and with nuclear magnetic resonance in organic molecular crystals give
a first strong support to this view.",0403678v1
2007-04-28,Atomic data from the Iron Project. LXIV. Radiative transition rates and collision strengths for Ca II,"This work reports radiative transition rates and electron impact excitation
rate coefficients for levels of the n= 3, 4, 5, 6, 7, 8 configurations of Ca
II. The radiative data were computed using the Thomas-Fermi-Dirac central
potential method in the frozen core approximation and includes the polarization
interaction between the valence electron and the core using a model potential.
This method allows for configuration interactions (CI) and relativistic effects
in the Breit-Pauli formalism. Collision strengths in LS-coupling were
calculated in the close coupling approximation with the R-matrix method. Then,
fine structure collision strengths were obtained by means of the
intermediate-coupling frame transformation (ICFT) method which accounts for
spin-orbit coupling effects. We present extensive comparisons with the most
recent calculations and measurements for Ca II as well as a comparison between
the core polarization results and the ""unpolarized"" values. We find that core
polarization affects the computed lifetimes by up to 20%. Our results are in
very close agreement with recent measurements for the lifetimes of metastable
levels. The present collision strengths were integrated over a Maxwellian
distribution of electron energies and the resulting effective collision
strengths are given for a wide range of temperatures. Our effective collision
strengths for the resonance transitions are within ~11% from previous values
derived from experimental measurements, but disagree with latter computations
using the distorted wave approximation.",0704.3807v1
2008-09-03,Phase transition and anomalous electronic behavior in layered dichalcogenide CuS (covellite) probed by NQR,"Nuclear quadrupole resonance (NQR) on copper nuclei has been applied for
studies of the electronic properties of quasi-two-dimensional low-temperature
superconductor CuS (covellite) in the temperature region between 1.47 and 290
K. Two NQR signals corresponding to two non-equivalent sites of copper in the
structure, Cu(1) and Cu(2), has been found. The temperature dependences of
copper quadrupole frequencies, line-widths and spin-lattice relaxation rates,
which so far had never been investigated so precisely for this material,
altogether demonstrate the structural phase transition near 55 K, which
accompanies transformations of electronic spectrum not typical for simple
metals. The analysis of NQR results and their comparison with literature data
show that the valence of copper ions at both sites is intermediate in character
between monovalent and divalent states with the dominant of the former. It has
been found that there is a strong hybridization of Cu(1) and Cu(2) conduction
bands at low temperatures, indicating that the charge delocalization between
these ions takes place even in 2D regime. Based on our data, the occurrence of
energy gap, charge fluctuations and charge-density waves, as well as the nature
of phase transition in CuS are discussed. It is concluded that some physical
properties of CuS are similar to those of high-temperature superconductors
(HTSC) in normal state.",0809.0560v1
2009-02-06,r-modes and mutual friction in rapidly rotating superfluid neutron stars,"We develop a new perturbative framework for studying the r-modes of rotating
superfluid neutron stars. Our analysis accounts for the centrifugal deformation
of the star, and considers the two-fluid dynamics at linear order in the
perturbed velocities. Our main focus is on a simple model system where the
total density profile is that of an $n=1$ polytrope. We derive a partially
analytic solution for the superfluid analogue of the classical r-mode. This
solution is used to analyse the relevance of the vortex mediated mutual
friction damping, confirming that this dissipation mechanism is unlikely to
suppress the gravitational-wave driven instability in rapidly spinning
superfluid neutron stars. Our calculation of the superfluid r-modes is
significantly simpler than previous approaches, because it decouples the r-mode
from all other inertial modes of the system. This leads to the results being
clearer, but it also means that we cannot comment on the relevance of potential
avoided crossings (and associated ""resonances"") that may occur for particular
parameter values. Our analysis of the mutual friction damping differs from
previous studies in two important ways. Firstly, we incorporate realistic
pairing gaps which means that the regions of superfluidity in the star's core
vary with temperature. Secondly, we allow the mutual friction parameters to
take the whole range of permissible values rather than focussing on a
particular mechanism. Thus, we consider not only the weak drag regime, but also
the strong drag regime where the fluid dynamics is significantly different.",0902.1149v1
2009-04-08,Effects of cobalt doping and three-dimensionality in $BaFe_2As_2$,"We investigate the dual roles of a cobalt impurity in the Ba-122
ferropnictide superconductor in the state with coexisting collinear spin
density wave (SDW) order as a dopant and as a scattering center, using first
principles electronic structure methods. The Co atom is found to dope the FeAs
plane where it is located with a single delocalized electron as expected, but
also induces a strong perturbation of the SDW ground state of the system. This
in turn induces a stripe-like modulation of the density of states in nearby
planes which may be observable in STM experiments. The defect is found to have
an intermediate strength nonmagnetic scattering potential with a range of
roughly 1 Angstrom, and the Co gives rise to a smaller but longer range
magnetic scattering potential. The impurity potential in both channels is
highly anisotropic, reflecting the broken symmetry of the SDW ground state. We
give values for the effective Co potentials for each d orbital on the impurity
and nearby sites. The calculation also shows a clear local resonance comprised
of Co states about 200meV above the Fermi level, in quantitative agreement with
a recent report from STM. Finally, we discuss the issue of the effective
dimensionality of the 122 materials, and show that the hybridization of the
out-of-phase As atoms leads to a higher density of states between the FeAs
planes relative to the 1111 counterparts.",0904.1257v2
2012-12-07,Theory of Attosecond Transient Absorption Spectroscopy of Krypton for Overlapping Pump and Probe Pulses,"We present the first fully ab initio calculations for attosecond transient
absorption spectroscopy of atomic krypton with overlapping pump and probe
pulses. Within the time-dependent configuration interaction singles (TDCIS)
approach, we describe the pump step (strong-field ionization using a
near-infrared pulse) as well as the probe step (resonant electron excitation
using an extreme- ultraviolet pulse) from first principles. We extent our TDCIS
model and account for the spin-orbit splitting of the occupied orbitals. We
discuss the spectral features seen in a recent attosecond transient absorption
experiment [A. Wirth et al., Science 334, 195 (2011)]. Our results support the
concept that the transient absorption signal can be directly related to the
instantaneous hole population even during the ionizing pump pulse. Furthermore,
we find strong deformations in the absorption lines when the overlap of pump
and probe pulses is maximum. These deformations can be described by relative
phase shifts in the oscillating ionic dipole. We discuss possible mechanisms
contributing to these phase shifts. Our finding suggests that the
non-perturbative laser dressing of the entire N -electron wave function is the
main contributor.",1212.1589v1
2014-08-25,Measurements of the exchange stiffness of YIG films by microwave resonance techniques,"Measurements of the exchange stiffness $D$ and the exchange constant $A$ of
Yttrium Iron Garnet (YIG) films are presented. The YIG films with thicknesses
from 0.9 $\mu$m to 2.6 $\mu$m were investigated with a microwave setup in a
wide frequency range from 5 to 40 GHz. The measurements were performed when the
external static magnetic field was applied in-plane and out-of-plane. The
method of Schreiber and Frait, based on the analysis of the perpendicular
standing spin wave (PSSW) mode frequency dependence on the applied out-of-plane
magnetic field, was used to obtain the exchange stiffness $D$. This method was
modified to avoid the influence of internal magnetic fields during the
determination of the exchange stiffness. Furthermore, the method was adapted
for in-plane measurements as well. The results obtained using all methods are
compared and values of $D$ between $(5.18\pm0.01) \cdot 10^{-17}$T$\cdot$m$^2$
and $(5.34\pm0.02) \cdot 10^{-17}$ T$\cdot$m$^2$ were obtained for different
thicknesses. From this the exchange constant was calculated to be $A=(3.65 \pm
0.38)~$pJ/m.",1408.5772v1
2017-05-02,Amplitude-dependent topological edge states in nonlinear phononic lattices,"This work investigates the effect of nonlinearities on topologically
protected edge states in one and two-dimensional phononic lattices. We first
show that localized modes arise at the interface between two spring-mass chains
that are inverted copies of each other. Explicit expressions derived for the
frequencies of the localized modes guide the study of the effect of cubic
nonlinearities on the resonant characteristics of the interface which are shown
to be described by a Duffing-like equation. Nonlinearities produce
amplitude-dependent frequency shifts, which in the case of a softening
nonlinearity cause the localized mode to migrate to the bulk spectrum. The case
of a hexagonal lattice implementing a phononic analogue of a crystal exhibiting
the quantum spin Hall effect is also investigated in the presence of weakly
nonlinear cubic springs. An asymptotic analysis provides estimates of the
amplitude dependence of the localized modes, while numerical simulations
illustrate how the lattice response transitions from bulk-to-edge
mode-dominated by varying the excitation amplitude. In contrast with the
interface mode of the first example studies, this occurs both for hardening and
softening springs. The results of this study provide a theoretical framework
for the investigation of nonlinear effects that induce and control
topologically protected wave-modes through nonlinear interactions and amplitude
tuning.",1705.01118v2
2020-08-21,Theory of polariton-electron interactions in semiconductor microcavities,"We develop a microscopic description of an electron-doped two-dimensional
semiconductor embedded in a microcavity. Specifically, we investigate the
interactions between exciton-polaritons and electrons for the case where the
interactions between charges are strongly screened and the system is spin
polarized. As a starting point, we obtain an analytic expression for the
exciton-polariton wave function, and we relate the microscopic parameters of
the light-matter system to experimentally measurable quantities, such as the
Rabi coupling and the cavity photon frequency. We then derive the
polariton-electron interaction within the standard Born approximation and
compare it with the exact polariton-electron scattering $T$ matrix that we
obtain from a diagrammatic approach that has proven highly successful in the
context of nuclear physics and ultracold atomic gases. In particular, we show
that the Born approximation provides an upper bound on the polariton-electron
coupling strength at vanishing momentum. Using our exact microscopic
calculation, we demonstrate that polariton-electron scattering can be strongly
enhanced compared to the exciton-electron case, which is the opposite of that
expected from the Born approximation. We furthermore expose a resonance-like
peak at scattering momenta near the polariton inflection point, whose size is
set by the strength of the light-matter coupling. Our results arise from the
non-Galilean nature of the polariton system and should thus be applicable to a
range of semiconductor microcavities such as GaAs quantum wells and atomically
thin materials.",2008.09292v2
2017-02-27,Ubiquitous formation of bulk Dirac cones and topological surface states from a single orbital manifold in transition-metal dichalcogenides,"Transition-metal dichalcogenides (TMDs) are renowned for their rich and
varied properties. They range from metals and superconductors to strongly
spin-orbit-coupled semiconductors and charge-density-wave systems, with their
single-layer variants one of the most prominent current examples of
two-dimensional materials beyond graphene. Their varied ground states largely
depend on the transition metal d-electron-derived electronic states, on which
the vast majority of attention has been concentrated to date. Here, we focus on
the chalcogen-derived states. From density-functional theory calculations
together with spin- and angle- resolved photoemission, we find that these
generically host type-II three-dimensional bulk Dirac fermions as well as
ladders of topological surface states and surface resonances. We demonstrate
how these naturally arise within a single p-orbital manifold as a general
consequence of a trigonal crystal field, and as such can be expected across a
large number of compounds. Already, we demonstrate their existence in six
separate TMDs, opening routes to tune, and ultimately exploit, their
topological physics.",1702.08177v2
2019-01-20,Terahertz Strong-Field Physics without a Strong External Terahertz Field,"Traditionally, strong-field physics explores phenomena in matter (atoms,
molecules, and solids) driven by an extremely strong laser field
nonperturbatively. However, even in the complete absence of an external
electromagnetic field, strong-field phenomena can arise when matter strongly
couples with the zero-point field of the quantum vacuum state, i.e.,
fluctuating electromagnetic waves whose expectation value is zero. Some of the
most striking examples of this occur in a cavity setting, in which an ensemble
of two-level atoms resonantly interacts with a single photonic mode of vacuum
fields, producing vacuum Rabi splitting. In particular, the nature of the
matter-vacuum-field coupled system fundamentally changes when the coupling rate
(equal to one half of the vacuum Rabi splitting) becomes comparable to, or
larger than, the resonance frequency. In this so-called ultrastrong coupling
regime, a non-negligible number of photons exist in the ground state of the
coupled system. Furthermore, the coupling rate can be cooperatively enhanced
(via so-called Dicke cooperativity) when the matter is comprised of a large
number of identical two-level particles, and a quantum phase transition is
predicted to occur as the coupling rate reaches a critical value. Low-energy
electronic or magnetic transitions in many-body condensed matter systems with
large dipole moments are ideally suited for searching for these predicted
phenomena. Here, we discuss two condensed matter systems that have shown
cooperative ultrastrong interactions in the terahertz frequency range: a
Landau-quantized two-dimensional electron gas interacting with
high-quality-factor cavity photons, and an Er$^{3+}$ spin ensemble interacting
with Fe$^{3+}$ magnons in ErFeO$_3$.",1901.06749v1
2019-10-30,Modal analysis of a spinning disk in a dense fluid as a model for high head hydraulic turbines,"In high head Francis turbines and pump-turbines in particular, Rotor Stator
Interaction (RSI) is an unavoidable source of excitation that needs to be
predicted accurately. Precise knowledge of turbine dynamic characteristics,
notably the variation of the rotor natural frequencies with rotation speed and
added mass of the surrounding water, is essential to assess potential resonance
and resulting amplification of vibrations. In these machines, the disk-like
structures of the runner crown and band as well as the head cover and bottom
ring give rise to the emergence of diametrical modes and a mode split
phenomenon for which no efficient prediction method exists to date. Fully
coupled Fluid-Structure Interaction (FSI) methods are too computationally
expensive; hence, we seek a simplified modelling tool for the design and the
expected-life prediction of these turbines. We present the development of both
an analytical modal analysis based on the assumed mode approach and potential
flow theory, and a modal force Computational Fluid Dynamics (CFD) approach for
rotating disks in dense fluid. Both methods accurately predict the natural
frequency split as well as the natural frequency drift within 7.9% of the
values measured experimentally. The analytical model explains how mode split
and drift are respectively caused by linear and quadratic dependence of the
added mass with relative circumferential velocity between flexural waves and
fluid rotation.",1910.14001v2
2020-01-23,Theoretical methods for ultrastrong light-matter interactions,"This article reviews theoretical methods developed in the last decade to
understand cavity quantum electrodynamics in the ultrastrong-coupling regime,
where the strength of the light-matter interaction becomes comparable to the
photon frequency. Along with profound modifications of fundamental quantum
optical effects giving rise to a rich phenomenology, this regime introduces
significant theoretical challenges. One of the most important is the break-down
of the rotating-wave approximation which neglects all non-resonant terms in
light-matter interaction Hamiltonians. Consequently, a large part of the
quantum optical theoretical framework has to be revisited in order to
accurately account for all interaction terms in this regime. We give in this
article a broad overview of the recent progress, ranging from analytical
estimate of ground-state properties to proper derivations of master equations
and computation of photodetection signals. For each aspect of the theory, the
basic principles of the methods are illustrated on paradigmatic models such as
quantum Rabi and spin-boson models. In this spirit, most of the article is
devoted to effective models, relevant for the various experimental platforms in
which the ultrastrong coupling has been reached, such as semiconductor
microcavities and superconducting circuits. The validity of these models is
discussed in the last part of the article, where we address recent debates on
fundamental issues related to gauge invariance in the ultrastrong-coupling
regime.",2001.08715v2
2022-02-15,Interplay of leakage radiation and protection in topological photonic crystal cavities,"The introduction of topological concepts to the design of photonic crystal
cavities holds great promise for applications in integrated photonics due to
the prospect of topological protection. This study examines the signatures of
topological light confinement in the leakage radiation of two-dimensional
topological photonic crystal cavities. The cavities are implemented in an
all-dielectric platform that features the photonic quantum spin Hall effect at
telecom wavelengths and supports helical edge states that are weakly coupled to
the radiation continuum. The modes of resonators scaling down to single point
defects in the surrounding bulk lattice are characterized via spectral position
and multipolar nature of the eigenstates. The mode profiles in real and
momentum space are mapped using far field imaging and Fourier
spectropolarimetry, revealing how certain properties of the cavity modes
reflect on their origin in the topological bandstructure. This includes
band-inversion-induced confinement and inverted scaling of mode spectra for
trivial and topological defect cavities. Furthermore, hallmarks of topological
protection in the loss rates are demonstrated, which are largely unaffected by
cavity shape and size. The results constitute an important step toward the use
of radiative topological cavities for on-chip confinement of light, control of
emitted wave fronts, and enhancing light-matter interactions.",2202.07620v2
2022-06-21,alpha-cluster structure of 18Ne,"In this work we study alpha-clustering in 18Ne and compare it with what is
known about clustering in the mirror nucleus 18O. The excitation function of
18Ne was measured in inverse kinematics from the resonant elastic scattering
reaction of 14O on 4He in the excitation energy range from 8 to 17 MeV, using
the active target TexAT. The analysis was performed using a multi-channel
R-matrix approach. Detailed spectroscopic information is obtained from the
R-matrix analysis: excitation energy of the states, spin and parity as well as
partial alpha and total widths. This information is compared with theoretical
models and previous data. Clustering structures appear to be robust and mostly
isospin symmetric. A good correspondence was found between the levels in 18O
and 18Ne. We carried out an extensive shell model analysis of the experimental
data. This comparison suggests that strongly clustered states remain organized
in relation to the corresponding reaction channel identified by the number of
nodes in the relative alpha plus core wave function. The agreement between
theory and experiment is very good and especially useful when it comes to
understanding the clustering strength distribution. The comparison of the
experimental data with theory shows that certain states, especially at high
excitation energies, are significantly more clustered than predicted. This
indicates that the structure of these states is collective and is aligned
towards the corresponding alpha reaction channel.",2206.10659v2
2022-12-02,Nonlinear behaviour of the nonradiative exciton reservoir in quantum wells,"Excitons and free charge carriers with large wave vectors form a nonradiative
reservoir, which can strongly affect properties of bright excitons due to the
exciton-exciton and exciton-carrier interactions. In the present work, the
dynamics of quasiparticles in the reservoir at different areal densities is
experimentally studied in a GaAs/AlGaAs quantum well using a time-resolved
reflectance spectroscopy of nonradiative broadening of exciton resonances. The
population of the reservoir is controlled either by the excitation power or by
the temperature of the structure under study. The dynamics is quantitatively
analyzed in the framework of the model developed earlier [Kurdyubov et al.,
Phys. Rev. B {\bf 104}, 035414 (2021)]. The model considers several dynamic
processes, such as scattering of photoexcited excitons into the reservoir,
dissociation of excitons into free charge carriers and the reverse process,
carrier-induced exciton scattering into the light cone depleting the reservoir,
thermally activated nonradiative losses of charge carriers. We have found that
competition of these processes leads to highly nonlinear dynamics of reservoir
excitons, although their density is far below the exciton Mott transition
densities. Characteristic rates of the processes and their dependencies on the
excitation power and the temperature are determined.",2212.01107v1
2023-07-05,Femtoscopy of $D$ mesons and light mesons upon unitarized effective field theories,"Hadron femtoscopy has turned into a powerful tool for accessing space-time
information of heavy-ion collisions as well as for studying final-state
interactions of hadrons. Recently, heavy-flavor femtoscopy has become feasible
using the ALICE detector at the LHC. We compute the correlation function of $D$
mesons and light mesons using an off-shell $T$-matrix approach to access the
two-meson wave function, and predict the correlation functions involving
charged $D^+, D^{*+},D_s^+$ and $D_s^{*+}$ with $\pi^\pm$ and $K^\pm$. From the
obtained results -- all of them accessible in $p+p$ collision experiments -- we
point up the case of $D^+ \pi^-$, which is sensitive to the lower state of the
two-pole $D_0^* (2300)$ system. The presence of such poles imprints a depletion
on the correlation function, which could potentially be detected in
experiments. While preliminary ALICE data do not show evidence of this effect,
we suggest to look into the $D_s^+ K^-$ system to explore the higher pole of
the $D_0^* (2300)$, as the depletion in the correlation function is more
pronounced. Using heavy-quark spin symmetry we also propose exploring the
effect of the two poles of the $D_1(2430)$ and predict similar structures in
the correlation functions of the $D^{*+} \pi^-$ and $D_s^{*+} K^-$ pairs.",2307.02102v2
2024-01-09,Microwave magnetic excitations in U-type hexaferrite Sr$_4$CoZnFe$_{36}$O$_{60}$ ceramics,"Microwave (MW) spectra of ferrimagnetic U-hexaferrite
Sr$_4$CoZnFe$_{36}$O$_{60}$ ceramics were studied using several experimental
techniques from 100 MHz to 50 GHz at temperatures between 10 and 390 K. They
revealed 9 excitations, which exhibit remarkable temperature dependences near
the magnetic phase transitions at 145 K and 305 K. Some of them also change
under the application of a weak bias magnetic field at room temperature. Three
lowest-frequency modes seen between 200 MHz and 3 GHz were assigned to the
dynamics of the magnetic domains. The mode attributed to the natural
ferromagnetic resonance exhibits a dramatic critical slowing-down from 25 GHz
at 390 K to 5 GHz near the 305 K phase transition, and again a hardening to ~11
GHz on further cooling. The higher-frequency excitations are most likely spin
wave (magnon) modes arising from the complex ferrimagnetic structure of
Sr$_4$CoZnFe$_{36}$O$_{60}$. The high sensitivity of the MW spectra to the weak
magnetic bias field $H$ < 700 Oe at room temperature is shown to be caused by
the transformation of the polydomain magnetic structure in randomly oriented
ceramic grains to a monodomain one. The MW response measured above 2 GHz using
coplanar and microstrip lines with different electromagnetic field distribution
and sample coupling revealed the same excitations with similar temperature and
bias field dependences. It confirms the reliability of the results and proves
the effectiveness of the used MW techniques.",2401.04678v1
2024-02-21,Multi-step topological transitions among meron and skyrmion crystals in a centrosymmetric magnet,"Topological swirling spin textures, such as skyrmions and merons, have
recently attracted much attention as a unique building block for high-density
magnetic information devices. The controlled transformation among different
types of such quasi-particles is an important challenge, while it was
previously achieved only in a few non-centrosymmetric systems characterized by
Dzyaloshinskii-Moriya interaction. Here, we report an experimental discovery of
multi-step topological transitions among a variety of meron and skyrmion
crystal states in a centrosymmetric magnet GdRu$_2$Ge$_2$. By performing the
detailed magnetic structure analysis based on resonant X-ray and neutron
scattering experiments as well as electron transport measurements, we have
found that this compound hosts periodic lattice of elliptic skyrmions,
meron/anti-meron pairs, and circular skyrmions as a function of external
magnetic field. The diameter of these objects is as small as 2.7 nm, which is
almost two orders of magnitude smaller than typical non-centrosymmetric
magnets. Such an intricate manner of topological magnetic transitions are well
reproduced by a theoretical model considering the competition between RKKY
interactions at inequivalent wave vectors. The present findings demonstrate
that even a simple centrosymmetric magnet with competing interactions can be a
promising material platform to realize a richer variety of nanometric magnetic
quasi-particles with distinctive symmetry and topology, whose stability may be
tunable by various external stimuli.",2402.13751v1
2006-02-24,Magnetization dynamics in dysprosium orthoferrites via inverse Faraday effect,"The ultrafast non-thermal control of magnetization has recently become
feasible in canted antiferromagnets through photomagnetic instantaneous pulses
[A.V. Kimel {\it et al.}, Nature {\bf 435}, 655 (2005)]. In this experiment
circularly polarized femtosecond laser pulses set up a strong magnetic field
along the wave vector of the radiation through the inverse Faraday effect,
thereby exciting non-thermally the spin dynamics of dysprosium orthoferrites. A
theoretical study is performed by using a model for orthoferrites based on a
general form of free energy whose parameters are extracted from experimental
measurements. The magnetization dynamics is described by solving coupled
sublattice Landau-Lifshitz-Gilbert equations whose damping term is associated
with the scattering rate due to magnon-magnon interaction. Due to the inverse
Faraday effect and the non-thermal excitation, the effect of the laser is
simulated by magnetic field Gaussian pulses with temporal width of the order of
hundred femtoseconds. When the field is along the z-axis, a single resonance
mode of the magnetization is excited. The amplitude of the magnetization and
out-of-phase behavior of the oscillations for fields in z and -z directions are
in good agreement with the cited experiment. The analysis of the effect of the
temperature shows that magnon-magnon scattering mechanism affects the decay of
the oscillations on the picosecond scale. Finally, when the field pulse is
along the x-axis, another mode is excited, as observed in experiments. In this
case the comparison between theoretical and experimental results shows some
discrepancies whose origin is related to the role played by anisotropies in
orthoferrites.",0602593v1
2004-01-07,Exotic Meson Production in the $f_{1}(1285)π^{-}$ System observed in the Reaction $π^{-} p \to ηπ^{+}π^{-}π^{-} p$ at 18 GeV/c,"This letter reports results from the partial wave analysis of the
$\pi^{-}\pi^{-}\pi^{+}\eta$ final state in $\pi^{-}p$ collisions at 18GeV/c.
Strong evidence is observed for production of two mesons with exotic quantum
numbers of spin, parity and charge conjugation, $J^{PC} = 1^{-+}$ in the decay
channel $f_{1}(1285)\pi^{-}$. The mass $M = 1709 \pm 24 \pm 41$ MeV/c^2 and
width $\Gamma = 403 \pm 80 \pm 115$ MeV/c^2 of the first state are consistent
with the parameters of the previously observed $\pi_{1}(1600)$. The second
resonance with mass $M = 2001 \pm 30 \pm 92$ MeV/c^2 and width $\Gamma = 333
\pm 52 \pm 49$ MeV/c^2 agrees very well with predictions from theoretical
models. In addition, the presence of $\pi_{2}(1900)$ is confirmed with mass $M
= 2003 \pm 88 \pm 148$ MeV/c^2 and width $\Gamma = 306 \pm 132 \pm 121$ MeV/c^2
and a new state, $a_{1}(2096)$, is observed with mass $M = 2096 \pm 17 \pm 121$
MeV/c^2 and width $\Gamma = 451 \pm 41 \pm 81$ MeV/c^2. The decay properties of
these last two states are consistent with flux tube model predictions for
hybrid mesons with non-exotic quantum numbers.",0401004v2
1993-09-20,Vector Color Transparency,"Color transparency (CT) in high momentum transfer $(e,e' \vec p)$ reactions
is explored. The spin of the proton and photon are treated explicitly, hence
the name ``Vector CT"". The Dirac distorted wave impulse approximation is used
as a starting point; then CT effects are embedded. A hadronic basis is used to
describe the struck proton as a wavepacket of physical baryon resonances. The
effects of the wavepacket expansion on the normal component of the ejectile
polarization, which vanishes in the limit of full CT, are investigated. This
formalism is also applied to study CT effects in total cross sections,
individual separated nuclear response functions, Fermi motion of the initial
nucleon, non-zero size of the initial wavepacket and the effects of
relativistic lower components. We show that including CT reduces the violations
of current conservation (CC), a typical problem in calculations of this kind.
The energy dependence of the normal polarization in $(e,e' \vec p)$ reactions
is found to be slow. However, a measurement of the normal transverse response
in a heavy nucleus, such as $^{208}Pb$ seems to afford the opportunity to see
CT at quite low momentum transfers. The effects of Fermi motion are
investigated, and choosing the momentum of the struck nucleon to be large leads
to significant violations of CC.",9309022v1
1994-04-05,Theory of parity violation in compound nuclear states; one particle aspects,"In this work we formulate the reaction theory of parity violation in compound
nuclear states using Feshbach's projection operator formalism. We derive in
this framework a complete set of terms that contribute to the longitudinal
asymmetry measured in experiments with polarized epithermal neutrons. We also
discuss the parity violating spreading width resulting from this formalism. We
then use the above formalism to derive expressions which hold in the case when
the doorway state approximation is introduced. In applying the theory we limit
ourselves in this work to the case when the parity violating potential and the
strong interaction are one-body. In this approximation, using as the doorway
the giant spin-dipole resonance and employing well known optical potentials and
a time-reversal even, parity odd one-body interaction we calculate or estimate
the terms we derived. In our calculations we explicitly orthogonalize the
continuum and bound wave functions. We find the effects of orthogonalization to
be very important. Our conclusion is that the present one-body theory cannot
explain the average longitudinal asymmetry found in the recent polarized
neutron experiments. We also confirm the discrepancy, first pointed out by
Auerbach and Bowman, that emerges, between the calculated average asymmetry and
the parity violating spreading width, when distant doorways are used in the
theory.",9404003v1
2008-10-28,Ensemble Control of Finite Dimensional Time-Varying Linear Systems,"In this article, we investigate the problem of simultaneously steering an
uncountable family of finite dimensional time-varying linear systems. We call
this class of control problems Ensemble Control, a notion coming from the study
of spin dynamics in Nuclear Magnetic Resonance (NMR) spectroscopy and imaging
(MRI). This subject involves controlling a continuum of parameterized dynamical
systems with the same open-loop control input. From a viewpoint of mathematical
control theory, this class of problems is challenging because it requires
steering a continuum of dynamical systems between points of interest in an
infinite dimensional state space by use of the same control function. The
existence of such a control raises fundamental questions of ensemble
controllability. We derive the necessary and sufficient controllability
conditions and an accompanying analytical optimal control law for ensemble
control of time-varying linear systems. We show that ensemble controllability
is in connection with singular values of the operator characterizing the system
dynamics. In addition, we study the problem of optimal ensemble control of
harmonic oscillators to demonstrate our main results. We show that the optimal
solutions are pertinent to the study of time-frequency limited signals and
prolate spheroidal wave functions. A systematic study of ensemble control
systems has immediate applications to systems with parameter uncertainties as
well as to broad areas of quantum control systems as arising in coherent
spectroscopy and quantum information processing. The new mathematical
structures appearing in such problems are an excellent motivation for new
developments in control theory.",0810.5116v2
2009-04-14,Neutron scattering patterns show Superconductivity in FeTe0.5Se0.5 likely results from itinerant electron fluctuations,"The discovery of the Fe pnictide superconductors generated great interest as
the structure consists of planes of a magnetic material quite similar to the
cuprate superconductors. Fe(Te0.5Se0.5) is a particularly simple system whose
planes are isostructural to the FeAs layers found in the originally discovered
superconductors of this type. We report here neutron scattering measurements on
this material that provide an understanding of the superconductivity. Since the
information about the Fermi surface is available both from photoemission and
band structure calculations for FeTe, FeSe and other related materials the
neutron spectra can be used to see if the itinerant electron picture is valid.
The results are consistent with a picture where there are both electron and
hole Fermi surfaces that make exact (pi,pi) transitions possible. This would
normally favor either a spin or charge density wave state. However, our
measurements show the extent of the region where (pi,pi) transitions take place
and demonstrate that there are a much larger number of transitions near pi,pi).
The near (pi,pi) transitions are observed both above and below Tc and are
expected to be strongly pairing. The superconductivity can be attributed to
these excitations while the exactly (pi,pi) transitions produce the narrow
resonance excitation that appears below Tc.",0904.2178v1
2013-06-04,Majorana bound states in d-wave superconductor-based hybrid systems,"For the search of Majorana fermions, we propose to employ a ramp-type
Josephson edge junction between a normal metal such as Au, Ag or alloys of
heavy metals and a topologically-trivial dx2-y2 wave high-Tc superconductor
YBa2Cu3O7. The success in forming the elusive zero-energy Majorana bound states
(MBS) at the junction relies crucially upon the strength of the Rashba
spin-orbit coupling (RSOC) at the metal/superconductor interface, the tunneling
direction, and the interface quality which includes a near zero tunnel barrier
height. When these junction conditions are collectively satisfied, definitive
signatures of Majorana fermions will emerge. After inspecting a vast amount of
published data of junctions that are close to what we have proposed, we were
able to find: 1) angular resonant Andreev reflection, and 2) quantized zero
bias normalized differential conductance peak (ZBCP), as possible evidence for
MBS formed at the junction interface. Encouraged by these findings, we have
designed a MBS-supporting d-wave superconductor based pi-loop heterostructure
as a qubit platform. Such pi-loops are characterized by a doubly degenerate
half flux quantum vortex (HQV) and are topologically protected by a parity
effect arising from an odd number of sign changes of the supercurrent
circulating in the loop. The topological protection is further enhanced by the
formation of RSOC induced Majorana bound states at the Josephson junction
interface. The proposed MBS-plus-HQV qubit platform will be useful for
demonstrating non-Abelian exchange statistics and for building a prototype
topological quantum computer.",1306.0652v2
2013-10-03,Quantum correlations in the 1-D driven dissipative transverse field XY model,"We study the non-equilibrium steady state (NESS) of a driven dissipative
one-dimensional system near a critical point, and explore how the quantum
correlations compare to the known critical behavior in the ground state. The
model we study corresponds to a cavity array driven parametrically at a two
photon resonance, equivalent in a rotating frame to a transverse field
anisotropic XY model [C. E. Bardyn and A. Imamo\u{g}lu, Phys. Rev. Lett {\bf
109} 253606 (2012)]. Depending on the sign of transverse field, the steady
state of the open system can be either related to the ground state or to the
maximum energy state. In both cases, many properties of the entanglement are
similar to the ground state, although no critical behavior occurs. As one
varies from the Ising limit to the isotropic XY limit, entanglement range
grows. The isotropic limit of the NESS is however singular, with simultaneously
diverging range and vanishing magnitude of entanglement. This singular limiting
behavior is quite distinct from the ground state behavior, it can however be
understood analytically within spin-wave theory.",1310.0964v2
2014-03-27,"Proton widths of the low-lying 16F states from the 15N(7Li, 6Li)16N reaction","All the 16F levels are unbound by proton emission. To date the four low-lying
16F levels below 1 MeV have been experimentally identified with well
established spin-parity values and excitation energies with an accuracy of 4 -
6 keV. However, there are still considerable discrepancies for their level
widths. The present work aims to explore these level widths through an
independent method. The angular distributions of the 15N(7Li, 6Li)16N reaction
leading to the first four states in 16N were measured using a high-precision
Q3D magnetic spectrograph. The neutron spectroscopic factors and the asymptotic
normalization coefficients for these states in 16N were then derived based on
distorted wave Born approximation analysis. The proton widths of the four
low-lying resonant states in 16F were obtained according to charge symmetry of
strong interaction.",1403.6912v1
2014-04-21,RVB superconductors with fermionic projected entangled pair states,"We construct a family of simple fermionic projected entangled pair states
(fPEPS) on the square lattice with bond dimension $D=3$ which are exactly
hole-doped resonating valence bond (RVB) wavefunctions with short-range singlet
bonds. Under doping the insulating RVB spin liquid evolves immediately into a
superconductor with mixed $d+is$ pairing symmetry whose pair amplitude grows as
the square-root of the doping. The relative weight between $s$-wave and
$d$-wave components can be controlled by a single variational parameter $c$. We
optimize our ansatz w.r.t. $c$ for the frustrated $t-J_1-J_2$ model (including
both nearest and next-nearest neighbor antiferromagnetic interactions $J_1$ and
$J_2$, respectively) for $J_2\simeq J_1/2$ and obtain an energy very close to
the infinite-PEPS state (using full update optimization and same bond
dimension). The orbital symmetry of the optimized RVB superconductor has
predominant d-wave character, although we argue a residual (complex s-wave)
time reversal symmetry breaking component should always be present. Connections
of the results to the physics of superconducting cuprates and pnictides are
outlined.",1404.5268v2
2014-11-28,Hidden charm and bottom molecular states,"We investigate heavy quark symmetries for heavy light meson-antimeson systems
in a contact-range effective field theory. In the SU(3) light flavor limit, the
leading order Lagrangian respecting heavy quark spin symmetry contains four
independent counter-terms. Neglecting $1/m_Q$ corrections, three of these low
energy constants can be determ1ined by theorizing a molecular description of
the $X(3872)$ and $Z_b(10610)$ states. Thus, we can predict new hadronic
molecules, in particular the isovector charmonium partners of the $Z_b(10610)$
and the $Z_b(10650)$ states. We also discuss hadron molecules composed of a
heavy meson and a doubly-heavy baryon, which would be related to the heavy
meson-antimeson molecules thanks to the heavy antiquark-diquark symmetry.
Finally, we also study the $X(3872) \to D^0\bar D^0\pi^0$ decay, which is not
only sensitive to the short distance part of the $X(3872)$ molecular wave
function, as the $J/\psi\pi\pi$ and $J/\psi3\pi$ $X(3872)$ decay modes are, but
it is also affected by the long-distance structure of the resonance.
Furthermore, this decay might provide some information on the interaction
between the $D\bar D$ charm mesons.",1411.7828v1
2015-01-20,Pairing versus quarteting coherence length,"We systematically analyse the coherence length in even-even nuclei. The
pairing coherence length in the spin-singlet channel for the effective density
dependent delta (DDD) and Gaussian interaction is estimated. We consider in our
calculations bound states as well as narrow resonances. It turns out that the
pairing gaps given by the DDD interaction are similar to those of the Gaussian
potential if one renormalizes the radial width to the nuclear radius. The
correlations induced by the pairing interaction have in all considered cases a
long range character inside the nucleus and decrease towards the surface. The
mean coherence length is larger than the geometrical radius for light nuclei
and approaches this value for heavy nuclei. The effect of the temperature and
states in continuum is investigated. Strong shell effects are evidenced,
especially for protons. We generalize this concept to quartets by considering
similar relations, but between proton and neutron pairs. The quartet coherence
length has a similar shape, but with larger values on the nuclear surface. We
evidence the important role of proton-neutron correlations by estimating the
so-called alpha coherence length, which takes into account the overlap with the
proton-neutron part of the $\alpha$-particle wave function. It turns out that
it does not depend on the nuclear size and has a value comparable to the free
$\alpha$-particle radius. We have shown that pairing correlations are mainly
concentrated inside the nucleus, while quarteting correlations are connected to
the nuclear surface.",1501.04984v1
2015-06-08,Experimental study of $η$ meson photoproduction reaction at MAMI,"New data for the differential cross sections, polarization observables $T$,
$F$, and $E$ in the reaction of $\eta$ photoproduction on proton from the
threshold up to a center-of-mass energy of W=1.9 GeV are presented. The data
were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged
photon facility of the Mainz Microtron MAMI. The polarization measurements were
made using a frozen-spin butanol target and circularly polarized photon beam.
The results are compared to existing experimental data and different PWA
predictions. The data solve a long-standing problem related the angular
dependence of older $T$ data close to threshold. The unexpected relative phase
motion between $s$- and $d$-wave amplitudes required by the old data is not
confirmed. At higher energies, all model predictions fail to reproduce the new
polarization data indicating a significant impact on our understanding of the
underlying dynamics of $\eta$ meson photoproduction. Furthermore, we present a
fit of the new data and existing data from GRAAL for $\Sigma$ asymmetry based
on an expansion in terms of associated Legendre polynomials. A Legendre
decomposition shows the sensitivity to small partial-wave contributions. The
sensitivity of the Legendre coefficients to the nucleon resonance parameters is
shown using the $\eta$MAID isobar model.",1506.02546v1
2015-11-06,Doublon dynamics and polar molecule production in an optical lattice,"Ultracold polar molecules provide an excellent platform to study quantum
many-body spin dynamics, which has become accessible in the recently realized
low entropy quantum gas of polar molecules in an optical lattice. To obtain a
detailed understanding for the molecular formation process in the lattice, we
prepare a density distribution where lattice sites are either empty or occupied
by a doublon composed of a bosonic atom interacting with a fermionic atom. By
letting this disordered, out-of-equilibrium system evolve from a well-defined
initial condition, we observe clear effects on pairing that arise from
inter-species interactions, a higher partial wave Feshbach resonance, and
excited Bloch-band population. When only the lighter fermions are allowed to
tunnel in the three-dimensional (3D) lattice, the system dynamics can be well
described by theory. However, in a regime where both fermions and bosons can
tunnel, we encounter correlated dynamics that is beyond the current capability
of numerical simulations. Furthermore, we show that we can probe the
microscopic distribution of the atomic gases in the lattice by measuring the
inelastic loss of doublons. These techniques realize tools that are generically
applicable to heteronuclear diatomic systems in optical lattices and can shed
light on molecule production as well as dynamics of a Bose-Fermi mixture.",1511.02225v1
2017-08-30,Suppression of the antiferromagnetic order when approaching the superconducting state in a phase-separated crystal of K$_x$Fe$_{2-y}$Se$_2$,"We have combined elastic and inelastic neutron scattering techniques,
magnetic susceptibility and resistivity measurements to study single-crystal
samples of K$_x$Fe$_{2-y}$Se$_2$, which contain the superconducting phase that
has a transition temperature of $\sim$31 K. In the inelastic neutron scattering
measurements, we observe both the spin-wave excitations resulting from the
block antiferromagnetic ordered phase and the resonance that is associated with
the superconductivity in the superconducting phase, demonstrating the
coexistence of these two orders. From the temperature dependence of the
intensity of the magnetic Bragg peaks, we find that well before entering the
superconducting state, the development of the magnetic order is interrupted, at
$\sim$42 K. We consider this result to be evidence for the physical separation
of the antiferromagnetic and superconducting phases; the suppression is
possibly due to the proximity effect of the superconducting fluctuations on the
antiferromagnetic order.",1708.09115v1
2019-11-21,Low damping and microstructural perfection of sub-40nm-thin yttrium iron garnet films grown by liquid phase epitaxy,"The field of magnon spintronics is experiencing an increasing interest in the
development of solutions for spin-wave-based data transport and processing
technologies that are complementary or alternative to modern CMOS
architectures. Nanometer-thin yttrium iron garnet (YIG) films have been the
gold standard for insulator-based spintronics to date, but a potential process
technology that can deliver perfect, homogeneous large-diameter films is still
lacking. We report that liquid phase epitaxy (LPE) enables the deposition of
nanometer-thin YIG films with low ferromagnetic resonance losses and
consistently high magnetic quality down to a thickness of 20 nm. The obtained
epitaxial films are characterized by an ideal stoichiometry and perfect film
lattices, which show neither significant compositional strain nor geometric
mosaicity, but sharp interfaces. Their magneto-static and dynamic behavior is
similar to that of single crystalline bulk YIG. We found, that the Gilbert
damping coefficient alpha is independent of the film thickness and close to 1 x
10-4, and that together with an inhomogeneous peak-to-peak linewidth broadening
of delta H0|| = 0.4 G, these values are among the lowest ever reported for YIG
films with a thickness smaller than 40 nm. These results suggest, that
nanometer-thin LPE films can be used to fabricate nano- and micro-scaled
circuits with the required quality for magnonic devices. The LPE technique is
easily scalable to YIG sample diameters of several inches.",1911.09400v1
2017-10-06,Investigation of the interfacial Dzyaloshinskii-Moriya interaction sign in Ir/Co2FeAl systems by Brillouin light scattering,"Co2FeAl (CFA) ultrathin films, of various thicknesses (0.9 nm<tCFA<1.8 nm),
have been grown by sputtering on Si substrates, using Ir as a buffer layer. The
magnetic properties of the structures have been studied by vibrating sample
magnetometry (VSM), miscrostrip ferromagnetic resonance (MS-FMR) and Brillouin
light scattering (BLS) in the Damon-Eshbach geometry. VSM characterizations
show that films are mostly in-plane magnetized and the perpendicular saturating
field increases with decreasing CFA thickness suggesting the existence of
interface anisotropy. The presence of magnetic dead layers of 0.44 nm has been
detected by VSM. The MS-FMR with perpendicular applied magnetic field has been
used to determine the gyromagnetic factor. The BLS measurements reveal a
pronounced nonreciprocal spin waves propagation, due to the interfacial
Dzyaloshinskii-Moriya interaction (DMI) induced by Ir interface with CFA, which
increases with decreasing CFA thickness. The DMI sign has been found to be the
same (negative) as that of Pt/Co, in contrast to the ab-initio calculation on
Ir/Co. The thickness dependence of the effective DMI constant shows the
existence of two regimes similarly to that of the perpendicular anisotropy
constant. The DMI constant Ds was estimated to be -0.37 pJ/m for the thickest
samples where a linear thickness dependence of the effective DMI constant has
been observed.",1710.02433v1
2019-09-24,Photoproduction of the $Λ$(1520) hyperon with a 9 GeV photon beam at GlueX,"The GlueX experiment is located at the Thomas Jefferson National Accelerator
Facility (JLab) in Newport News, VA, USA. It features a hermetic 4$\pi$
detector with excellent tracking and calorimetry capabilities. Its 9 GeV
linearly polarized photon beam is produced from the 12 GeV electron beam,
delivered by JLab's Continuous Electron Beam Accelerator Facility (CEBAF), via
bremsstrahlung on a thin diamond and is incident on a LH2 target. GlueX
recently finished its first data taking period and published first results. The
main goal of GlueX is to measure gluonic excitations of mesons. These so-called
hybrid or exotic mesons are predicted by Quantum Chromodynamics (QCD) but
haven't been experimentally confirmed yet. They can have quantum numbers not
accessible by ordinary quark-antiquark pairs which helps in identifying them
using partial wave analysis techniques. The search for exotic mesons requires a
very good understanding of photoproduction processes in a wide range of final
states, one of them being $pK^{+}K^{-}$ which contains many meson and baryon
reactions. The $\Lambda$(1520) is a prominent hyperon resonance in this final
state and is the subject of this presentation. This talk will give an
introduction to the GlueX experiment and show preliminary results for the
photoproduction of the $\Lambda$(1520) hyperon. The measurement of important
observables like the photon beam asymmetry and spin-density matrix elements
will be discussed and an outlook to possible measurements of further hyperon
states in the $pK^{+}K^{-}$ final state will be given.",1909.10877v2
2019-12-19,Unravelling competing microscopic interactions at a phase boundary: a single crystal study of the metastable antiferromagnetic pyrochlore Yb$_{2}$Ge$_{2}$O$_{7}$,"We report inelastic neutron scattering measurements from our newly
synthesized single crystals of the structurally metastable antiferromagnetic
pyrochlore Yb$_{2}$Ge$_{2}$O$_{7}$. We determine the four symmetry-allowed
nearest-neighbor anisotropic exchange parameters via fits to linear spin wave
theory supplemented by fits of the high-temperature specific heat. The exchange
parameters so-determined are strongly correlated to the values determined for
the $g$-tensor components, as previously observed for the related Yb pyrochlore
Yb$_{2}$Ti$_{2}$O$_{7}$. To address this issue, we directly determined the
$g$-tensor from electron paramagnetic resonance of 1% Yb-doped
Lu$_{2}$Ge$_{2}$O$_{7}$, thus enabling an unambiguous determination of the
exchange parameters. Our results show that Yb$_{2}$Ge$_{2}$O$_{7}$ resides
extremely close to the classical phase boundary between an antiferromagnetic
$\Gamma_5$ phase and a splayed ferromagnet phase. By juxtaposing our results
with recent ones on Yb$_{2}$Ti$_{2}$O$_{7}$, our work illustrates that the Yb
pyrochlore oxides represent ideal systems for studying quantum magnets in close
proximity to classical phase boundaries.",1912.09448v2
2021-12-08,Dark discrete breather modes in monoaxial chiral helimagnet with easy-plane anisotropy,"Nonlinearity and discreteness are two pivotal factors for an emergence of
discrete breather excitations in various media. We argue that these
requirements are met in the forced ferromagnetic phase of the monoaxial chiral
helimagnet CrNb$_3$S$_6$ due to specific domain structure of the compound. The
stationary, time-periodic breather modes appear as the discrete breather
lattice solutions whose period mismatches with a system size. Thanks to
easy-plane single-ion anisotropy intrinsic to CrNb$_3$S$_6$, these modes are of
the dark type with frequencies lying within the linear spin-wave band, close to
its bottom edge. They represent cnoidal states of magnetization, similar to the
well-known soliton lattice ground state, with differing but limited number of
embedded $2\pi$-kinks. Linear stability of these dark breather modes is
verified by means of the Floquet analysis. Their energy controlled by two
parameters, namely the breather lattice period and amplitude, falls off
linearly with a growth of the kink number. These results may pave a new path to
design spintronic resonators on the base of chiral helimagnets.",2112.04341v1
2022-04-28,Multi-wavelength magnetic coding of helical luminescence in ferromagnetic 2D layered CrI3,"Two-dimensional (2D) van der Waals (vdW) ferromagnets have opened new avenues
for manipulating spin at the limits of single or few atomic layers, and for
creating unique magneto-exciton devices through the coupling of long-range
ferromagnetic (FM) orders and excitons. However, 2D vdW ferromagnets explored
so far have rarely possessed exciton behaviors; to date, FM CrI3 have been
recently revealed to show ligand-field photoluminescence correlated with FM
ordering, but typically with a broad emission peak. Alternatively, many-body
excitons have been observed in antiferromagnetic (AFM) NiPS3, but the coupling
of excitons with AFM orders is exponentially more difficult, owing to extremely
high coercivity. Here, we report a straightforward approach to realize strong
coupling of narrow helical emission and FM orders at a low magnetic field in
CrI3 through a relatively simple microsphere cavity. We show that the resonant
whispering-gallery-modes (WGM) of SiO2 microspheres give rising to a series of
strong oscillation helical emissions with a full width at half-maximum (FWHM)
of ~5 nm under continuous wave excitation. Reversible magnetic control and
coding of helical luminescence with multiwavelength is realized in the range of
950-1100 nm. This work enables plenty of opportunities for creating magnetic
encoding lasing for photonic integrated chips.",2204.13318v1
2022-08-22,Crossover from Fermi Arc to Full Fermi Surface,"The Fermi surface as a contour of the gapless quasiparticle excitation in
momentum space is studied based on a mean-field theory of the doped Mott
insulator, where the underlying pseudogap phase is characterized by a
two-component resonating-valence-bond (RVB) order that vanishes in the
overdoping at $\delta>\delta^*$. Here the quasiparticle emerges as a
``collective'' mode and a Fermi arc is naturally present in the pseudogap
regime, while a full Fermi surface is recovered at $\delta>\delta^*$. The area
enclosed by the gapless quasiparticle contour still satisfies the Luttinger
volume in both cases, and the ``Fermi arc'' at $\delta<\delta^*$ is actually
due to a significant reduction of the spectral weight caused by a quasiparticle
fractionalization in the antinodal region. The endpoints of the Fermi arcs
exhibit enhanced density of states or ``hotspots'', which can further give rise
to a charge-density-wave-like quasiparticle interference pattern. At the
critical doping $\delta^*$, the fractionalized spin excitations become gapless
and incoherent which is signaled by a divergent specific heat. At
$\delta>\delta^*$, the quasiparticle excitation restores the coherence over the
full Fermi surface, but the fractionalization still persists at a higher
energy/temperature which may be responsible for a strange metal behavior.
Different mechanisms for the Fermi arc and experimental comparisons are briefly
discussed.",2208.10519v2
2022-09-15,Emergent charge order and unconventional superconductivity in pressurized kagome superconductor CsV3Sb5,"The discovery of multiple electronic orders in kagome superconductors AV3Sb5
(A = K, Rb, Cs) provides a promising platform for exploring unprecedented
emergent physics. Under moderate pressure (< 2.2 GPa), the triple-Q charge
density wave (CDW) order is monotonically suppressed by pressure, while the
superconductivity displays a two-dome-like behavior, suggesting an unusual
interplay between superconductivity and CDW order. Given that time-reversal
symmetry breaking and electronic nematicity have been revealed inside the
triple-Q CDW phase, understanding this CDW order and its interplay with
superconductivity becomes one of the core questions in AV3Sb5. Here, we report
the evolution of CDW and superconductivity with pressure in CsV3Sb5 by 51V
nuclear magnetic resonance measurements. An emergent CDW phase, ascribed to a
possible stripe-like CDW order with a unidirectional 4a0 modulation, is
observed between Pc1 ~ 0.58 GPa and Pc2 ~ 2.0 GPa, which explains the
two-dome-like superconducting behavior under pressure. Furthermore, the nuclear
spin-lattice relaxation measurement reveals evidence for pressure-independent
charge fluctuations above the CDW transition temperature and unconventional
superconducting pairing above Pc2. Our results not only shed new light on the
interplay of superconductivity and CDW but also reveal novel electronic
correlation effects in kagome superconductors AV3Sb5.",2209.07340v1
2023-08-08,Chiral Optical Nano-Cavity with Atomically Thin Mirrors,"A fundamental requirement for photonic technologies is the ability to control
the confinement and propagation of light. Widely utilized platforms include
two-dimensional (2D) optical microcavities in which electromagnetic waves are
confined between either metallic or multi-layer dielectric distributed Bragg
reflectors. However, the fabrication complexities of thick Bragg reflectors and
high losses in metallic mirrors have motivated the quest for efficient and
compact mirrors. Recently, 2D transition metal dichalcogenides hosting tightly
bound excitons with high optical quality have emerged as promising atomically
thin mirrors. In this work, we propose and experimentally demonstrate a
sub-wavelength 2D nano-cavity using two atomically thin mirrors with degenerate
resonances. Remarkably, we show how the excitonic nature of the mirrors enables
the formation of chiral and tunable optical modes upon the application of an
external magnetic field. Moreover, temperature-dependent reflectance
measurements indicate robustness and tunability up to $\approx\!100$ K for the
device. Our work establishes a new regime for engineering intrinsically chiral
sub-wavelength optical cavities and opens avenues for realizing spin-photon
interfaces and exploring chiral many-body cavity electrodynamics.",2308.04574v1
2023-12-12,Kondo coherence versus superradiance in THz radiation-driven heavy-fermion systems,"In strongly correlated systems such as heavy-fermion materials, the coherent
superposition of localized and mobile spin states leads to the formation of
Kondo resonant states, which on a dense, periodic array of Kondo ions develop
lattice coherence. Characteristically, these quantum-coherent superposition
states respond to a terahertz (THz) excitation by a delayed THz pulse on the
scale of the material's Kondo energy scale and, hence, independent of the
pump-light intensity. However, delayed response is also typical for
superradiance in an ensemble of excited atoms. In this case, quantum coherence
is established by the coupling to an external, electromagnetic mode and, hence,
dependent on the pump-light intensity. In the present work, we investigate the
physical origin of the delayed pulse, i.e., inherent, correlation-induced
versus light-induced coherence, in the prototypical heavy-fermion compound
CeCu_5.9Au_0.1. We study the delay, duration and amplitude of the THz pulse at
various temperatures in dependence on the electric-field strength of the
incident THz excitation, ranging from 0.3 to 15.2 kV/cm. We observe a robust
delayed response at approximately 6 ps with an amplitude proportional to the
amplitude of the incident THz wave. This is consistent with theoretical
expectation for the Kondo-like coherence and thus provides compelling evidence
for the dominance of condensed-matter versus optical coherence in the
heavy-fermion compound.",2312.06931v1
2024-02-04,Untangle charge-order dependent bulk states from surface effects in a topological kagome metal ScV$_6$Sn$_6$,"Kagome metals with charge density wave (CDW) order exhibit a broad spectrum
of intriguing quantum phenomena. The recent discovery of the novel kagome CDW
compound ScV$_6$Sn$_6$ has spurred significant interest. However, understanding
the interplay between CDW and the bulk electronic structure has been obscured
by a profusion of surface states and terminations in this quantum material.
Here, we employ photoemission spectroscopy and potassium dosing to elucidate
the complete bulk band structure of ScV$_6$Sn$_6$, revealing multiple van Hove
singularities near the Fermi level. We surprisingly discover a robust
spin-polarized topological Dirac surface resonance state at the M point within
the two-fold van Hove singularities. Assisted by the first-principle
calculations, the temperature dependence of the $k_z$- resolved ARPES spectrum
provides unequivocal evidence for the proposed
$\sqrt{3}$$\times$$\sqrt{3}$$\times3$ charge order over other candidates. Our
work not only enhances the understanding of the CDW-dependent bulk and surface
states in ScV$_6$Sn$_6$ but also establishes an essential foundation for
potential manipulation of the CDW order in kagome materials.",2402.02341v1
2024-03-22,"Spectrum of $S$- and $P$-wave $cc\bar{q}\bar{q}'$ $(\bar{q},\bar{q}' = \bar{u}, \bar{d}, \bar{s})$ systems in a chiral SU(3) quark model","Inspired by the resonance $T_{cc}^+(3875)$ recently observed by the LHCb
Collaboration, we systematically explore the $S$- and $P$-wave
$cc\bar{q}\bar{q}'$ $(\bar{q},\bar{q}' = \bar{u}, \bar{d}, \bar{s})$ systems in
a chiral SU(3) quark model. The Hamiltonian contains the kinetic energy, the
one-gluon-exchange (OGE) potential, the confinement potential, and the
one-boson-exchange (OBE) potential stemming from the coupling of quark and
chiral fields. The Schr\""odinger equation is solved by use of the variational
method with the spacial trial wave functions chosen as Gaussian functions. It
is found that the lowest state has a mass $3879$ MeV, isospin and spin-parity
$IJ^P=01^+$, and quark constituent $cc\bar{u}\bar{d}$, in agreement with the
experimentally observed $T_{cc}^+(3875)$. This state is approximately at the
calculated $DD^\ast$ threshold, and has a root-mean-square radius about $0.48$
fm. These demonstrates that the $T_{cc}^+(3875)$ can be accommodated as a
stable and compact tetraquark sate in the chiral SU(3) quark model. All the
other $S$- and $P$-wave $cc\bar{q}\bar{q}'$ $(\bar{q},\bar{q}' = \bar{u},
\bar{d}, \bar{s})$ states lie about one hundred to few hundreds MeV higher than
the corresponding meson-meson thresholds, and thus are not suggested to be
candidates of stable and compact tetraquark states due to their fall-apart
decays to two mesons.",2403.15187v1
2024-04-07,Element-specific ultrafast lattice dynamics in FePt nanoparticles,"Light-matter interaction at the nanoscale in magnetic alloys and
heterostructures is a topic of intense research in view of potential
applications in high-density magnetic recording. While the element-specific
dynamics of electron spins is directly accessible to resonant x-ray pulses with
femtosecond time structure, the possible element-specific atomic motion remains
largely unexplored. We use ultrafast electron diffraction to probe the temporal
evolution of lattice Bragg peaks of FePt nanoparticles embedded in a carbon
matrix following excitation by an optical femtosecond laser pulse. The
diffraction interference between Fe and Pt sublattices enables us to
demonstrate that the Fe mean-square vibration amplitudes are significantly
larger that those of Pt as expected from their different atomic mass. Both are
found to increase as energy is transferred from the laser-excited electrons to
the lattice. Contrary to this intuitive behavior, we observe a laser-induced
lattice expansion that is larger for Pt than for Fe atoms during the first
picosecond after laser excitation. This effect points to the strain-wave driven
lattice expansion with the longitudinal acoustic Pt motion dominating that of
Fe.",2404.04980v2
2012-04-12,Quantum Decoherence of the Central Spin in a Sparse System of Dipolar Coupled Spins,"The central spin decoherence problem has been researched for over 50 years in
the context of both nuclear magnetic resonance and electron spin resonance.
Until recently, theoretical models have employed phenomenological stochastic
descriptions of the bath-induced noise. During the last few years, cluster
expansion methods have provided a microscopic, quantum theory to study the
spectral diffusion of a central spin. These methods have proven to be very
accurate and efficient for problems of nuclear-induced electron spin
decoherence in which hyperfine interactions with the central electron spin are
much stronger than dipolar interactions among the nuclei. We provide an
in-depth study of central spin decoherence for a canonical scale-invariant
all-dipolar spin system. We show how cluster methods may be adapted to treat
this problem in which central and bath spin interactions are of comparable
strength. Our extensive numerical work shows that a properly modified cluster
theory is convergent for this problem even as simple perturbative arguments
begin to break down. By treating clusters in the presence of energy detunings
due to the long-range (diagonal) dipolar interactions of the surrounding
environment and carefully averaging the effects over different spin states, we
find that the nontrivial flip-flop dynamics among the spins becomes effectively
localized by disorder in the energy splittings of the spins. This localization
effect allows for a robust calculation of the spin echo signal in a dipolarly
coupled bath of spins of the same kind, while considering clusters of no more
than 6 spins. We connect these microscopic calculation results to the existing
stochastic models. We, furthermore, present calculations for a series of
related problems of interest for candidate solid state quantum bits including
donors and quantum dots in silicon as well as nitrogen-vacancy centers in
diamond.",1204.2834v2
2005-01-31,Leading Wave as a Component of the Spiral Pattern of the Galaxy,"The spiral pattern of the Galaxy identified by analyzing the kinematics of
young stars within 3 kpc of the Sun is Fourier decomposed into spiral
harmonics. The spiral pattern of the Galaxy is shown to be representable as a
superposition of trailing and leading waves with interarm distances of
1.8(+/-0.4) kpc and 4(+/-2) kpc, respectively. Shock waves are probably present
only in the portions of the trailing spiral pattern where it crosses the crest
of the leading wave. The small interarm distance of the trailing spiral wave
(1.8 kpc) can be explained by its evolution - by the decrease in the interarm
distance as the wave is displaced toward the inner Lindblad resonance. The
Carina arm may be part of this resonance ring.",0501673v1
1997-08-21,Amplitude equations for coupled electrostatic waves in the limit of weak instability,"We consider the simplest instabilities involving multiple unstable
electrostatic plasma waves corresponding to four-dimensional systems of mode
amplitude equations. In each case the coupled amplitude equations are derived
up to third order terms. The nonlinear coefficients are singular in the limit
in which the linear growth rates vanish together. These singularities are
analyzed using techniques developed in previous studies of a single unstable
wave. In addition to the singularities familiar from the one mode problem,
there are new singularities in coefficients coupling the modes. The new
singularities are most severe when the two waves have the same linear phase
velocity and satisfy the spatial resonance condition $k_2=2k_1$. As a result
the short wave mode saturates at a dramatically smaller amplitude than that
predicted for the weak growth rate regime on the basis of single mode theory.
In contrast the long wave mode retains the single mode scaling. If these
resonance conditions are not satisfied both modes retain their single mode
scaling and saturate at comparable amplitudes.",9708004v1
2001-12-26,Stationary states of Jaynes-Cummings model with atomic center-of-mass quantum motion: direct comparison of standing-wave and counterpropagating-waves cases,"The eigenstate problem of the Jaynes-Cummings model on the basis of complete
Hamiltonian, including the center-of -mass kinetic energy operator, is treated.
The energy spectrum and wave functions in standing-wave (SW)- and
counterpropagating waves (CPW)- cases are calculated and compared with each
other. It is shown that in CPW-case i) the atomic momentum distribution is
asymmetric and somewhat narrower in general; ii) the concept of quasimomentum
is not applicable and instead the ordinary momentum concerns the problem; iii)
atomic and photonic state distributions are self-consistent, and, in
consequence iiii) mean number of photons in the counterpropagating traveling
waves and mean atomic momentum match. Explicit analytic expressions for energy
eigenvalues and eigenfunctions are found in Tavis -Cummings-type approximation
[Phys. Rev. 170, 379(1968)] and is pointed, that it implies only the
bounded-like states for atomic center-of-mass motion. It is also shown that if
the recoil energy is taken into account, the Doppleron resonance is split into
two branches, one of which diverges to Bragg-like resonance in the high-order
range.",0112164v1
2004-09-10,Quantum shutter approach to tunneling time scales with wave packets,"The quantum shutter approach to tunneling time scales (G. Garc\'{\i
}a-Calder\'{o}n and A. Rubio, Phys. Rev. A \textbf{55}, 3361 (1997)), which
uses a cutoff plane wave as the initial condition, is extended in such a way
that a certain type of wave packet can be used as the initial condition. An
analytical expression for the time evolved wave function is derived. The
time-domain resonance, the peaked structure of the probability density (as the
function of time) at the exit of the barrier, originally found with the cutoff
plane wave initial condition, is studied with the wave packet initial
conditions. It is found that the time-domain resonance is not very sensitive to
the width of the packet when the transmission process is in the tunneling
regime.",0409060v3
2007-08-30,Resonant Atom Traps for Electromagnetic Waves,"Exitation of atomic levels due to interaction with electromagnetic waves has
been the subject of numerous works, both experimental and theoretical. This
topic became of interest in accelerator physics in relation to high efficiency
charge exchange injection into rings for high beam power applications. Taking
equations of resonant atom-wave interaction equations as a basis, this paper
shows that there exist some interesting phenomena which lead to the existence
of trapped electomagnetic waves (photon traps) in a medium that consists of
atoms with transition frequencies in proximity to the wave frequency. These
traps may exist in random and periodic lattices, and may have very low loss
rate. The atomic medium can serve as an excellent wavegiude or tool to form and
transmit electromagnetic waves for applications to accelerators and to
electromagnetic devices in general, where high pressure gas use is acceptable.
In addition, such traps in gases may accumulate substantial energy for a long
period of time, leading to the possibility of creating objects similar (or
equivalent) to ball lightning.",0708.4055v1
2009-06-26,Transient effects and reconstruction of the energy spectra in the time evolution of transmitted Gaussian wave packets,"We derive an exact analytical solution to the time-dependent Schr\""odinger
equation for transmission of a Gaussian wave packet through an arbitrary
potential of finite range. We consider the situation where the initial Gaussian
wave packet is sufficiently broad in momentum space to guarantee that the
resonance structure of the system is included in the dynamical description. We
demonstrate that the transmitted wave packet exhibits a transient behavior
which at very large distances and long times may be written as the free
evolving Gaussian wave packet solution times the transmission amplitude of the
system and hence it reproduces the resonance spectra of the system. This is a
novel result that predicts the ultimate fate of the transmitted Gaussian wave
packet. We also prove that at a fixed distance and very long times the solution
goes as $t^{-3/2}$ which extends to arbitrary finite range potentials previous
analysis on this issue. Our results are exemplified for single and multibarrier
systems.",0906.4994v2
2011-03-14,"Poles, the only true resonant-state signals, are extracted from a worldwide collection of partial wave amplitudes using only one, well controlled pole-extraction method","Each and every energy dependent partial-wave analysis is parameterizing the
pole positions in a procedure defined by the way how the continuous energy
dependence is implemented. These pole positions are, henceforth, inherently
model dependent. To reduce this model dependence, we use only one,
coupled-channel, unitary, fully analytic method based on the isobar
approximation to extract the pole positions from the each available member of
the worldwide collection of partial wave amplitudes which are understood as
nothing more but a good energy dependent representation of genuine experimental
numbers assembled in a form of partial-wave data. In that way, the model
dependence related to the different assumptions on the analytic form of the
partial-wave amplitudes is avoided, and the true confidence limit for the
existence of a particular resonant state, at least in one model, is
established. The way how the method works, and first results are demonstrated
for the S11 partial wave.",1103.2653v1
2011-03-17,Heating of ions by low-frequency Alfvén waves in partially ionized plasmas,"In the solar atmosphere, the chromospheric and coronal plasmas are much
hotter than the visible photosphere. The heating of the solar atmosphere,
including the partially ionized chromosphere and corona, remains largely
unknown. In this paper we demonstrate that the ions can be substantially heated
by Alfv\'{e}n waves with very low frequencies in partially ionized low beta
plasmas. This differs from other Alfv\'{e}n wave related heating mechanisms
such as ion-neutral collisional damping of Alfv\'{e}n waves and heating
described by previous work on resonant Alfv\'{e}n wave heating. In this paper,
we find that the non-resonant Alfv\'{e}n wave heating is less efficient in
partially ionized plasmas than when there are no ion-neutral collisions, and
the heating efficiency depends on the ratio of the ion-neutral collision
frequency to the ion gyrofrequency.",1103.3328v1
2011-12-27,Conversion of terahertz wave polarization at the boundary of a layered superconductor due to the resonance excitation of oblique surface waves,"We predict a complete TM-TE transformation of the polarization of terahertz
electromagnetic waves reflected from a strongly anisotropic boundary of a
layered superconductor. We consider the case when the wave is incident on the
superconductor from a dielectric prism separated from the sample by a thin
vacuum gap. The physical origin of the predicted phenomenon is similar to the
Wood anomalies known in optics, and is related to the resonance excitation of
the oblique surface waves. We also discuss the dispersion relation for these
waves, propagating along the boundary of the superconductor at some angle with
respect to the anisotropy axis, as well as their excitation by the
attenuated-total-reflection method.",1112.5924v1
2012-01-24,Measuring the phase of the scattering amplitude with vortex beams,"We show that colliding vortex beams instead of (approximate) plane waves can
lead to a direct measurement of how the overall phase of the plane wave
scattering amplitude changes with the scattering angle. Since vortex beams are
coherent superpositions of plane waves with different momenta, their scattering
amplitude receives contributions from plane wave amplitudes with distinct
kinematics. These contributions interfere, leading to the measurement of their
phase difference. Although interference exists for any generic wave packet
collision, we show that using vortex beams dramatically enhances sensitivity to
the phase in comparison with non-vortex beams. Since the overall phase is
inaccessible in a plane wave collision, this measurement would be of great
importance for a number of topics in hadronic physics, for example, meson
production in the resonance region, physics of nucleon resonances, and small
angle elastic hadron scattering.",1201.5040v2
2012-02-21,Wave functions of composite hadron states and relationship to couplings of scattering amplitudes for general partial waves,"In this paper we present the connection between scattering amplitudes in
momentum space and wave functions in coordinate space, generalizing previous
work done for s-waves to any partial wave. The relationship to the wave
function of the residues of the scattering amplitudes at the pole of bound
states or resonances is investigated in detail. A sum rule obtained for the
couplings provides a generalization to coupled channels, any partial wave and
bound or resonance states, of Weinberg's compositeness condition, which was
only valid for weakly bound states in one channel and s-wave. An example,
requiring only experimental data, is shown for the $\rho$ meson indicating that
it is not a composite particle of $\pi \pi$ but something else.",1202.4607v3
2012-11-05,Ultralow frequency acoustic resonances and its potential for mitigating tsunami wave formation,"Bubbles display astonishing acoustical properties since they are able to
absorb and scatter large amounts of energy coming from waves whose wavelengths
are two orders of magnitude larger than the bubble size. Thus, as the
interaction distance between bubbles is much larger than the bubble size,
clouds of bubbles exhibit collective oscillations which can scatter acoustic
waves three orders magnitude larger than the bubble size. Here we propose
bubble based systems which resonate at frequencies that match the time scale
relevant for seismogenic tsunami wave generation and may mitigate the
devastating effects of tsunami waves. Based on a linear approximation, our
na\""ive proposal may open new research paths towards the mitigation of tsunami
waves generation.",1211.1070v1
2013-06-12,Alternate islands of multiple isochronous chains in wave-particle interactions,"We analyze the dynamics of a relativistic particle moving in a uniform
magnetic field and perturbed by a standing electrostatic wave. We show that a
pulsed wave produces an infinite number of perturbative terms with the same
winding number, which may generate islands in the same region of phase space.
As a consequence, the number of isochronous island chains varies as a function
of the wave parameters. We observe that in all the resonances, the number of
chains is related to the amplitude of the various resonant terms. We determine
analytically the position of the periodic points and the number of island
chains as a function of the wave number and wave period. Such information is
very important when one is concerned with regular particle acceleration, since
it is necessary to adjust the initial conditions of the particle to obtain the
maximum acceleration.",1306.2682v3
2015-04-25,Adiabatic asymmetric scattering of atoms in the field of a standing wave,"A model of the asymmetric coherent scattering process (caused by initial
atomic wave-packet splitting in the momentum space) taking place at the large
detuning and adiabatic course of interaction for an effective two-state system
interacting with a standing wave of laser radiation is discussed. We show that
the same form of initial wave-packet splitting may lead to different, in
general, diffraction patterns for opposite, adiabatic and resonant, regimes of
the standing-wave scattering. We show that the scattering of the Gaussian wave
packet in the adiabatic case presents refraction (a limiting form of the
asymmetric scattering) in contrast to the bi-refringence (the limiting case of
the high-order narrowed scattering) occurring in the resonant scattering.",1504.06675v1
2015-08-23,Weak and strong interactions between dark solitons and dispersive waves,"The effect of mutual interaction between dark solitons and dispersive waves
is investigated numerically and analytically. The condition of the resonant
scattering of dispersive waves on dark solitons is derived and compared against
the results of numerical simulations. It is shown that the interaction with
intense dispersive waves affects the dynamics of the soltons strongly changing
their frequencies and accelerating or decelerating the solitons. It is also
demonstrated that two dark solitons can form a cavity for dispersive weaves
bouncing between the two dark solitons. The differences of the resonant
scattering of the dispersive waves on the dark and bright solitons are
discussed. In particular we demonstrate that two dark solitons and dispersive
wave bouncing in between them create solitonic cavity with convex ""mirrors""
unlike the concave ""mirror"" in case of the bright solitons.",1508.05596v1
2016-09-07,Proton heating by pick-up ion driven cyclotron waves in the outer heliosphere: Hybrid expanding box simulations,"Using one-dimensional hybrid expanding box model we investigate properties of
the solar wind in the outer heliosphere. We assume a proton-electron plasma
with a strictly transverse ambient magnetic field and, beside the expansion, we
take into account influence of a continuous injection of cold pick-up protons
through the charge-exchange process between the solar wind protons and hydrogen
of interstellar origin. The injected cold pick-up protons form a ring
distribution function that rapidly becomes unstable and generate Alfv\'en
cyclotron waves. The Alfv\'en cyclotron waves scatter pick-up protons to a
spherical shell distribution function that thickens over that time owing to the
expansion-driven cooling. The Alf\'ven cyclotron waves heat solar wind protons
in the perpendicular direction (with respect to the ambient magnetic field)
through the cyclotron resonance. At later times, the Alfv\'en cyclotron waves
become parametrically unstable and the generated ion acoustic waves heat
protons in the parallel direction through the Landau resonance. The resulting
heating of the solar wind protons is efficient on the expansion time scale.",1609.01955v1
2017-12-22,Shaping electron wave functions in a carbon nanotube with a parallel magnetic field,"A magnetic field, through its vector potential, usually causes measurable
changes in the electron wave function only in the direction transverse to the
field. Here we demonstrate experimentally and theoretically that in carbon
nanotube quantum dots, combining cylindrical topology and bipartite hexagonal
lattice, a magnetic field along the nanotube axis impacts also the longitudinal
profile of the electronic states. With the high (up to 17T) magnetic fields in
our experiment the wave functions can be tuned all the way from ""half-wave
resonator"" shape, with nodes at both ends, to ""quarter-wave resonator"" shape,
with an antinode at one end. This in turn causes a distinct dependence of the
conductance on the magnetic field. Our results demonstrate a new strategy for
the control of wave functions using magnetic fields in quantum systems with
nontrivial lattice and topology.",1712.08545v5
2017-05-18,Fluid-loaded metasurfaces,"We consider wave propagation along fluid-loaded structures which take the
form of an elastic plate augmented by an array of resonators forming a
metasurface, that is, a surface structured with sub-wavelength resonators. Such
surfaces have had considerable recent success for the control of wave
propagation in electromagnetism and acoustics, by combining the vision of
sub-wavelength wave manipulation, with the design, fabrication and size
advantages associated with surface excitation. We explore one aspect of recent
interest in this field: graded metasurfaces, but within the context of
fluid-loaded structures.
  Graded metasurfaces allow for selective spatial frequency separation and are
often referred to as exhibiting rainbow trapping. Experiments, and theory, have
been developed for acoustic, electromagnetic, and even elastic, rainbow devices
but this has not been approached for fluid-loaded structures that support
surface waves coupled with the acoustic field in a bulk fluid. This surface
wave, coupled with the fluid, can be used to create an additional effect by
designing a metasurface to mode convert from surface to bulk waves. We
demonstrate that sub-wavelength control is possible and that one can create
both rainbow trapping and mode conversion phenomena for a fluid-loaded elastic
plate model.",1705.08407v1
2019-02-21,The energy cascade of surface wave turbulence: toward identifying the active wave coupling,"We investigate experimentally turbulence of surface gravity waves in the
Coriolis facility in Grenoble by using both high sensitivity local probes and a
time and space resolved stereoscopic reconstruction of the water surface. We
show that the water deformation is made of the superposition of weakly
nonlinear waves following the linear dispersion relation and of bound waves
resulting from non resonant triadic interaction. Although the theory predicts a
4-wave resonant coupling supporting the presence of an inverse cascade of wave
action, we do not observe such inverse cascade. We investigate 4-wave coupling
by computing the tricoherence i.e. 4-wave correlations. We observed very weak
values of the tricoherence at the frequencies excited on the linear dispersion
relation that are consistent with the hypothesis of weak coupling underlying
the weak turbulence theory.",1902.08013v1
2019-03-12,Probing GHz Gravitational Waves with Graviton-magnon Resonance,"A novel method for extending frequency frontier in gravitational wave
observations is proposed. It is shown that gravitational waves can excite a
magnon. Thus, gravitational waves can be probed by a graviton-magnon detector
which measures resonance fluorescence of magnons. Searching for gravitational
waves with a wave length $\lambda$ by using a ferromagnetic sample with a
dimension $l$, the sensitivity of the graviton-magnon detector reaches spectral
densities, around $5.4 \times 10^{-22} \times (\frac{l}{\lambda /2\pi})^{-2} \
[{\rm Hz}^{-1/2}]$ at 14 GHz and $8.6 \times 10^{-21} \times (\frac{l}{\lambda
/2\pi})^{-2} \ [{\rm Hz}^{-1/2}]$ at 8.2 GHz, respectively.",1903.04843v4
2021-02-19,Quantum plasmon enhanced nonlinear wave mixing in graphene nanoflakes,"A distant-neighbor quantum-mechanical method is used to study the nonlinear
optical wave mixing in graphene nanoflakes (GNFs), including sum- and
difference-frequency generation, as well as four-wave mixing. Our analysis
shows that molecular-scale GNFs support quantum plasmons in the visible
spectrum region, and significant enhancement of nonlinear optical wave mixing
is achieved. Specifically, the second- and third-order wave-mixing
polarizabilities of GNFs are dramatically enhanced, provided that one (or more)
of the input or output frequencies coincide with a quantum plasmon resonance.
Moreover, by embedding a cavity into hexagonal GNFs, we show that one can break
the structural inversion symmetry and enable otherwise forbidden second-order
wave mixing, which is found to be enhanced by the quantum plasmon resonance
too. This study reveals that the molecular-sized graphene could be used in the
quantum regime for nanoscale nonlinear optical devices and ultrasensitive
molecular sensors.",2102.09843v3
2021-02-23,Scattering Problems via Real-time Wave Packet Scattering,"In this paper, we use a straightforward numerical method to solve scattering
models in one-dimensional lattices based on a tight-binding band structure. We
do this by using the wave packet approach to scattering, which presents a more
intuitive physical picture than the traditional plane wave approach. Moreover,
a general matrix diagonalization method that is easily accessible to
undergraduate students taking a first course in quantum mechanics is used.
Beginning with a brief review of wave packet transport in the continuum limit,
comparisons are made with its counterpart in a lattice. The numerical results
obtained through the diagonalization method are then benchmarked against
analytic results. The case of a resonant dimer is investigated in the lattice,
and several resonant values of the mean wave packet momentum are identified.
The transmission coefficients obtained for a plane wave incident on a step
potential and rectangular barrier are compared by investigating an equivalent
scenario in a lattice. Lastly, we present several short simulations of the
scattering process which emphasize how a simple methodology can be used to
visualize some remarkable phenomena.",2103.01027v2
2021-03-16,Rotation-translation coupling of a double-headed brownian motor in a traveling-wave potential,"Considering a double-headed Brownian motor moving with both translational and
rotational degrees of freedom, we investigate the directed transport properties
of the system in a traveling-wave potential. It is found that the traveling
wave provides the essential condition of the directed transport for the system,
and at an appropriate angular frequency, the positive current can be optimized.
A general current reversal appears by modulating the angular frequency of the
traveling wave, noise intensity, external driving force and the rod length. By
transforming the dynamical equation in traveling-wave potential into that in a
tilted potential, the mechanism of current reversal is analyzed. For both cases
of Gaussian and Levy noises, the currents show similar dependence on the
parameters. Moreover, the current in the tilted potential shows a typical
stochastic resonance effect. The external driving force has also a
resonance-like effect on the current in the tilted potential. But the current
in the traveling-wave potential exhibits the reverse behaviors of that in the
tilted potential. Besides, the currents obviously depend on the stability index
of the Levy noise under certain conditions.",2103.09109v1
2022-08-25,Path integral action for a resonant detector of gravitational waves in the generalized uncertainty principle framework,"The Heisenberg uncertainty principle gets modified by the introduction of an
observer independent minimal length. In this work we have considered the
resonant gravitational wave detector in the modified uncertainty principle
framework where we have used the position momentum uncertainty relation with a
quadratic order correction only. We have then used the path integral approach
to calculate an action for the bar detector in presence of a gravitational wave
and then derived the Lagrangian of the system leading to the equation of motion
for the configuration-space position coordinate in one dimension. We then find
a perturbative solution for the coordinate of the detector for a circularly
polarized gravitational wave leading to a classical solution of the same for
given initial conditions. Using this classical form of the coordinate of the
detector, we finally obtain the classical form of the on-shell action
describing the harmonic oscillator-gravitational wave system. Finally, we have
obtained the free particle propagator containing the quantum fluctuation term
considering gravitational wave interaction.",2208.12162v1
2023-04-17,Derivation of a generalized quasi-geostrophic approximation for inviscid flows in a channel domain: The fast waves correction,"This paper is devoted to investigating the rotating Boussinesq equations of
inviscid, incompressible flows with both fast Rossby waves and fast internal
gravity waves. The main objective is to establish a rigorous derivation and
justification of a new generalized quasi-geostrophic approximation in a channel
domain with no normal flow at the upper and lower solid boundaries, taking into
account the resonance terms due to the fast and slow waves interactions. Under
these circumstances, We are able to obtain uniform estimates and compactness
without the requirement of either well-prepared initial data (as in [10]) or
domain with no boundary (as in [17]). In particular, the nonlinear resonances
and the new limit system, which takes into account the fast waves correction to
the slow waves dynamics, are also identified without introducing Fourier series
expansion. The key ingredient includes the introduction of (full) generalized
potential vorticity.",2304.08303v1
2006-08-03,Two interacting spins in external fields. Four-level systems,"In the present article, we consider the so-called two-spin equation that
describes four-level quantum systems. Recently, these systems attract attention
due to their relation to the problem of quantum computation. We study general
properties of the two-spin equation and show that the problem for certain
external backgrounds can be identified with the problem of one spin in an
appropriate background. This allows one to generate a number of exact solutions
for two-spin equations on the basis of already known exact solutions of the
one-spin equation. Besides, we present some exact solutions for the two-spin
equation with an external background different for each spin but having the
same direction. We study the eigenvalue problem for a time-independent spin
interaction and a time-independent external background. A possible analogue of
the Rabi problem for the two-spin equation is defined. We present its exact
solution and demonstrate the existence of magnetic resonances in two specific
frequencies, one of them coinciding with the Rabi frequency, and the other
depending on the rotating field magnitude. The resonance that corresponds to
the second frequency is suppressed with respect to the first one.",0608036v1
2013-04-10,Magnetization and spin dynamics of the spin S=1/2 hourglass nanomagnet Cu5(OH)2(NIPA)4*10H2O,"We report a combined experimental and theoretical study of the spin S=1/2
nanomagnet Cu5(OH)2(NIPA)4*10H2O (Cu5-NIPA). Using thermodynamic, electron spin
resonance and 1H nuclear magnetic resonance measurements on one hand, and ab
initio density-functional band-structure calculations, exact diagonalizations
and a strong coupling theory on the other, we derive a microscopic magnetic
model of Cu5-NIPA and characterize the spin dynamics of this system. The
elementary five-fold Cu2+ unit features an hourglass structure of two
corner-sharing scalene triangles related by inversion symmetry. Our microscopic
Heisenberg model comprises one ferromagnetic and two antiferromagnetic exchange
couplings in each triangle, stabilizing a single spin S=1/2 doublet ground
state (GS), with an exactly vanishing zero-field splitting (by Kramer's
theorem), and a very large excitation gap of \Delta~68 K. Thus, Cu5-NIPA is a
good candidate for achieving long electronic spin relaxation (T1) and coherence
(T2) times at low temperatures, in analogy to other nanomagnets with low-spin
GS's. Of particular interest is the strongly inhomogeneous distribution of the
GS magnetic moment over the five Cu2+ spins. This is a purely
quantum-mechanical effect since, despite the non-frustrated nature of the
magnetic couplings, the GS is far from the classical collinear ferrimagnetic
configuration. Finally, Cu5-NIPA is a rare example of a S=1/2 nanomagnet
showing an enhancement in the nuclear spin-lattice relaxation rate 1/T1 at
intermediate temperatures.",1304.2826v1
2013-07-23,Harnessing nuclear spin polarization fluctuations in a semiconductor nanowire,"Soon after the first measurements of nuclear magnetic resonance (NMR) in a
condensed matter system, Bloch predicted the presence of statistical
fluctuations proportional to $1/\sqrt{N}$ in the polarization of an ensemble of
$N$ spins. First observed by Sleator et al., so-called ""spin noise"" has
recently emerged as a critical ingredient in nanometer-scale magnetic resonance
imaging (nanoMRI). This prominence is a direct result of MRI resolution
improving to better than 100 nm^3, a size-scale in which statistical spin
fluctuations begin to dominate the polarization dynamics. We demonstrate a
technique that creates spin order in nanometer-scale ensembles of nuclear spins
by harnessing these fluctuations to produce polarizations both larger and
narrower than the natural thermal distribution. We focus on ensembles
containing ~10^6 phosphorus and hydrogen spins associated with single InP and
GaP nanowires (NWs) and their hydrogen-containing adsorbate layers. We monitor,
control, and capture fluctuations in the ensemble's spin polarization in
real-time and store them for extended periods. This selective capture of large
polarization fluctuations may provide a route for enhancing the weak magnetic
signals produced by nanometer-scale volumes of nuclear spins. The scheme may
also prove useful for initializing the nuclear hyperfine field of electron spin
qubits in the solid-state.",1307.6007v1
2016-06-15,Quantum Computing with Acceptor Spins in Silicon,"The states of a boron acceptor near a Si/SiO2 interface, which bind two
low-energy Kramers pairs, have exceptional properties for encoding quantum
information and, with the aid of strain, both heavy hole and light hole-based
spin qubits can be designed. Whereas a light-hole spin qubit was introduced
recently [Phys. Rev. Lett. 116, 246801 (2016)], here we present analytical and
numerical results proving that a heavy-hole spin qubit can be reliably
initialised, rotated and entangled by electrical means alone. This is due to
strong Rashba-like spin-orbit interaction terms enabled by the interface
inversion asymmetry. Single qubit rotations rely on electric-dipole spin
resonance (EDSR), which is strongly enhanced by interface-induced spin-orbit
terms. Entanglement can be accomplished by Coulomb exchange, coupling to a
resonator, or spin-orbit induced dipole-dipole interactions. By analysing the
qubit sensitivity to charge noise, we demonstrate that interface-induced
spin-orbit terms are responsible for sweet spots in the dephasing time T2* as a
function of the top gate electric field, which are close to maxima in the EDSR
strength, where the EDSR gate has high fidelity. We show that both qubits can
be described using the same starting Hamiltonian, and by comparing their
properties we show that the complex interplay of bulk and interface-induced
spin-orbit terms allows a high degree of electrical control and makes acceptors
potential candidates for scalable quantum computation in Si.",1606.04697v1
2019-06-18,Nuclear magnetic resonance spectroscopy with a superconducting flux qubit,"We theoretically analyze the performance of the nuclear magnetic resonance
(NMR) spectroscopy with a superconducting flux qubit (FQ). Such NMR with the FQ
is attractive because of the possibility to detect the relatively small number
of nuclear spins in a local region ($\sim\mu$m) with low temperatures ($\sim$
mK) and low magnetic fields ($\sim$ mT), in which other types of quantum
sensing schemes cannot easily access. A sample containing nuclear spins is
directly attached on the FQ, and the FQ is used as a magnetometer to detect
magnetic fields from the nuclear spins. Especially, we consider two types of
approaches to NMR with the FQ. One of them is to use spatially inhomogeneous
excitations of the nuclear spins, which are induced by a spatially asymmetric
driving with radio frequency~(RF) pulses. Such an inhomogeneity causes a change
in the DC magnetic flux penetrating a loop of the FQ, which can be detected by
a standard Ramsey measurement on the FQ. The other approach is to use a
dynamical decoupling on the FQ to measure AC magnetic fields induced by Larmor
precession of the nuclear spins. In this case, neither a spin excitation nor a
spin polarization is required since the signal comes from fluctuating magnetic
fields of the nuclear spins. We calculate the minimum detectable density
(number) of the nuclear spins for the FQ with experimentally feasible
parameters. We show that the minimum detectable density (number) of the nuclear
spins with these approaches is around $10^{21}$ /cm$^3$ ($10^8$) with an
accumulation time of a second.",1906.07386v1
2020-09-29,High-fidelity single-shot readout of single electron spin in diamond with spin-to-charge conversion,"High fidelity single-shot readout of qubits is a crucial component for
fault-tolerant quantum computing and scalable quantum networks. In recent
years, the nitrogen-vacancy (NV) center in diamond has risen as a leading
platform for the above applications. The current single-shot readout of the NV
electron spin relies on resonance fluorescence method at cryogenic temperature.
However, the the spin-flip process interrupts the optical cycling transition,
therefore, limits the readout fidelity. Here, we introduce a spin-to-charge
conversion method assisted by near-infrared (NIR) light to suppress the
spin-flip error. This method leverages high spin-selectivity of cryogenic
resonance excitation and high flexibility of photonionization. We achieve an
overall fidelity $>$ 95% for the single-shot readout of an NV center electron
spin in the presence of high strain and fast spin-flip process. With further
improvements, this technique has the potential to achieve spin readout fidelity
exceeding the fault-tolerant threshold, and may also find applications on
integrated optoelectronic devices.",2009.14172v1
2008-06-28,Spin-dependent scattering in a silicon transistor,"The scattering of conduction electrons off neutral donors depends sensitively
on the relative orientation of their spin states. We present a theory of
spin-dependent scattering in the two dimensional electron gas (2DEG) of field
effect transistors. Our theory shows that the scattering mechanism is dominated
by virtual transitions to negatively ionized donor levels. This effect
translates into a source-drain current that always gets reduced when donor
spins are at resonance with a strong microwave field. We propose a model for
donor impurities interacting with conduction electrons in a silicon transistor,
and compare our explicit numerical calculations to electrically detected
magnetic resonance (EDMR) experiments. Remarkably, we show that EDMR is optimal
for donors placed into a sweet spot located at a narrow depth window quite far
from the 2DEG interface. This allows significant optimization of spin signal
intensity for the minimal number of donors placed into the sweet spot, enabling
the development of single spin readout devices. Our theory reveals an
interesting dependence on conduction electron spin polarization p_c. As p_c
increases upon spin injection, the EDMR amplitude first increases as p_{c}^{2},
and then saturates when a polarization threshold p_T is reached. These results
show that it is possible to use EDMR as an in-situ probe of carrier spin
polarization in silicon and other materials with weak spin-orbit coupling.",0806.4638v3
2020-10-23,Room Temperature Coherent Control of Spin Defects in hexagonal Boron Nitride,"Optically active defects in solids with accessible spin states are promising
candidates for solid state quantum information and sensing applications. To
employ these defects as quantum building blocks, coherent manipulation of their
spin state is required. Here we realize coherent control of ensembles of boron
vacancy (V$_B^-$) centers in hexagonal boron nitride (hBN). Specifically, by
applying pulsed spin resonance protocols, we measure spin-lattice relaxation
time ($T_1$) of 18 $\mu$s and spin coherence time ($T_2$) of 2 $\mu$s at room
temperature. The spin-lattice relaxation time increases by three orders of
magnitude at cryogenic temperature. Furthermore, employing a two- and
three-pulse electron spin-echo envelope modulation (ESEEM) we separate the
quadrupole and hyperfine interactions with the surrounding nuclei. Finally, by
applying a method to decouple the spin state from its inhomogeneous nuclear
environment - a ""hole-burning"" - the spectral optically detected magnetic
resonance linewidth is significantly reduced to several tens of kHz, thus
extending the spin coherence time by a factor of three. Our results are
important for employment of van der Waals materials for quantum technologies,
specifically in the context of using hBN as a high-resolution quantum sensor
for hybrid quantum systems including 2D heterostructures, nanoscale devices and
emerging atomically thin magnets.",2010.12513v1
2022-08-31,Single spin Landau-Zener-Stückelberg-Majorana interferometry of Zeeman-split states with strong spin-orbit interaction in a double quantum dot,"Single spin state evolution induced by the
Landau-Zener-St\""uckelberg-Majorana (LZSM) interference in a Zeeman-spit four
level system in a periodically driven double quantum dot is studied
theoretically by the Floquet stroboscopic method. An interplay between
spin-conserving and spin-flip tunneling processes with the Electric Dipole Spin
Resonance (EDSR) that is induced in an individual dot and enhanced by the LZSM
multiple level crossings with the neighboring quantum dot is investigated as a
function of the microwave (MW) frequency, driving amplitude, interdot detuning,
and magnetic field. A number of special points in the parameter space are
identified, out of which where all the three features are merged. Under this
triple-crossing resonance condition the interdot tunneling is combined with a
fast spin evolution in each dot at the EDSR frequency. Harmonics of the EDSR
are revealed in the spin-dependent tunneling maps versus variable magnetic
field and MW frequency. The results are applicable for both electron and hole
systems with strong spin-orbit interaction and may be useful for developing new
time-efficient schemes of the spin control and readout in qubit devices.",2208.14965v3
2022-12-17,Electronic Density of States of a $U\left(1\right)$ Quantum Spin Liquid with Spinon Fermi Surface. II. Zeeman Magnetic Field Effects,"The Zeeman effect lowers the energy of electrons with spin states which are
anti-parallel to the applied magnetic field but lifts that of spin parallel
states. In quantum spin liquids where the spin and charge degrees of freedom
are fractionalized, anomalous Zeeman response may be expected. In the case of
spin liquids with spinon Fermi surface, the threshold energy to excite an
electronic state is found to exhibit no Zeeman shift. This is specific to the
spinon Fermi surface case. In contrast, other gapped spin liquids are expected
to exhibit the standard Zeeman shift at the band edge even though they also
exhibit spin-charge fractionalization. When gauge field fluctuations are
included, we find that the Zeeman shift of the electronic states gets affected
by the gauge field induced binding. In the electronic density of states
spectra, weak gauge binding induces band edge resonance peaks which exhibit the
Zeeman shift in the same direction as that in the standard Zeeman effect, but
the shift is reduced as the binding potential increases. With further increase
in the binding potential the resonance becomes true in-gap bound states and
eventually the shift direction reverses so it is opposite to the standard
Zeeman effect. We propose that one can perform spin polarized scanning
tunneling microscope measurements as a test of the spinon Fermi sea ground
state in quantum spin liquid candidate materials.",2212.08768v3
2023-02-09,Spin-dependent recombination mechanisms for quintet bi-excitons generated through singlet fission,"We investigate the physical mechanisms for spin-dependent recombination of a
strongly bound pair of triplet excitons generated by singlet fission and
forming a spin quintet (total spin of two) bi-exciton. For triplet excitons the
spin-dependent recombination pathways can involve intersystem crossing or
triplet-triplet annihilation back to the singlet ground state. However the
modeling of spin-dependent recombination for quintets is still an open
question. Here we introduce two theoretical models and compare their
predictions with the broadband optically detected magnetic resonance spectrum
of a long lived quintet bi-exciton with known molecular structure. This
spectrum measures the change in the fluorescence signal induced by microwave
excitation of each of the ten possible spin transitions within the quintet
manifold as function of the magnetic field. While most of the experimental
features can be reproduced for both models, the behavior of some of the
transitions is only consistent with the quintet spin-recombination model
inspired by triplet intersystem crossing which can reproduce accurately the
experimental two-dimensional spectrum with a small number of kinetic
parameters. Thus quantitative analysis of the broadband optically detected
magnetic resonance signal enables quantitative understanding of the dominant
spin-recombination processes and estimation of the out-of equilibrium spin
populations.",2302.04678v2
2024-04-08,Effect of collective spin excitation on electronic transport in topological spin texture,"We develop an efficient real-time simulation method for the spin-charge
coupled system in the velocity gauge. This method enables us to compute the
real-time simulation for the two-dimensional system with the complex spin
texture. We focus on the effect of the collective excitation of the localized
spins on the electronic transport properties of the non-trivial topological
state in real space. To investigate this effect, we calculate the linear
optical conductivity by calculating the real-time evolution of the Kondo
lattice model on the triangular lattice, which hosts an all-in/all-out magnetic
structure. In the linear conductivity spectra, we observe multiple peaks below
the bandgap regime, attributed to the resonant contributions of collective
modes similar to the skyrmionic system, alongside broadband modifications
resulting from off-resonant spin dynamics. The result shows that the collective
excitation, similar to the skyrmionic system, influences the optical response
of the electron systems based on symmetry analysis. We elucidate the
interference between the contributions from the different spin excitations to
the optical conductivity in the multiple spin texture, pointing out the
mode-dependent electrical activity. We show the complex interplay between the
complex spin texture and the itinerant electrons in the two-dimensional
spin-charge coupled system.",2404.05204v1
1999-11-30,Anomalous resonance phenomena of solitary waves with internal modes,"We investigate the non-parametric, pure ac driven dynamics of nonlinear
Klein-Gordon solitary waves having an internal mode of frequency $\Omega_i$. We
show that the strongest resonance arises when the driving frequency
$\delta=\Omega_i/2$, whereas when $\delta=\Omega_i$ the resonance is weaker,
disappearing for nonzero damping. At resonance, the dynamics of the kink center
of mass becomes chaotic. As we identify the resonance mechanism as an {\em
indirect} coupling to the internal mode due to its symmetry, we expect similar
results for other systems.",9911487v1
2003-11-06,Cyclotron resonance of correlated electrons in semiconductor heterostructures,"The cyclotron resonance absorption of two-dimensional electrons in
semiconductor heterostructures in high magnetic fields is investigated. It is
assumed that the ionized impurity potential is a dominant scattering mechanism,
and the theory explicitly takes the Coulomb correlation effect into account
through the Wigner phonons. The cyclotron resonance linewidth is in
quantitative agreement with the experiment in the Wigner crystal regime at
T=4.2K. Similar to the cyclotron resonance theory of the charge density waves
pinned by short-range impurities, the present results for the long-range
scattering also show the doubling of the resonance peaks. However, unlike the
case of the charge density waves, our theory gives the pinning mode independent
of the bulk compressibility of the substrate materials.",0311134v1
2004-04-29,Resonant Interactions in Rotating Homogeneous Three-dimensional Turbulence,"Direct numerical simulations of three-dimensional (3D) homogeneous turbulence
under rapid rigid rotation are conducted to examine the predictions of resonant
wave theory for both small Rossby number and large Reynolds number. The
simulation results reveal that there is a clear inverse energy cascade to the
large scales, as predicted by 2D Navier-Stokes equations for resonant
interactions of slow modes. As the rotation rate increases, the
vertically-averaged horizontal velocity field from 3D Navier-Stokes converges
to the velocity field from 2D Navier-Stokes, as measured by the energy in their
difference field. Likewise, the vertically-averaged vertical velocity from 3D
Navier-Stokes converges to a solution of the 2D passive scalar equation. The
energy flux directly into small wave numbers in the $k_z=0$ plane from
non-resonant interactions decreases, while fast-mode energy concentrates closer
to that plane. The simulations are consistent with an increasingly dominant
role of resonant triads for more rapid rotation.",0404055v1
1999-06-08,Resonances and Off-Shell Characteristics of Effective Interactions,"The importance of including experimental resonances in constructing effective
inter-cluster interactions has been investigated. For this, we first address
the question of how to obtain the analytical properties of the Jost function in
regions of physical interest on the complex k-plane when the potential is given
in a tabular form. We then employ the Marchenko inverse scattering method to
construct, numerically, phase equivalent local potentials supporting the same
bound state(s) but having different resonance spectra which affect the
off-shell characteristics of the corresponding scattering amplitudes. This
implies that the inclusion of the experimental resonances in constructing a
potential would change its shape, strength, and range which in turn would
modify the bound and scattering wave functions in the interior region. This is
expected to have important consequences in calculations of transition
amplitudes in nuclear reaction theories, which strongly depend on the behaviour
of the wave functions at short distances. The influence of Supersymmetric
Transformations on the position and movement of resonances has also been
investigated.",9906020v1
2003-08-23,Model Dependence of the Properties of S11 Baryon Resonances,"The properties of baryon resonances are extracted from a complicated process
of fitting sophisticated, empirical models to data. The reliability of this
process comes from the quality of data and the robustness of the models
employed. With the large of amount of data coming from recent experiments, this
is an excellent time for a study of the model dependence of this extraction
process. A test case is chosen where many theoretical details of the model are
required, the S11 partial wave. The properties of the two lowest N* resonances
in this partial wave are determined using various models of the resonant and
non-resonant amplitudes.",0308066v2
2003-11-18,Near-field enhancement and imaging in double planar polariton-resonant structures,"It is shown that a system of two coupled planar material sheets possessing
surface mode (polariton) resonances can be used for the purpose of evanescent
field restoration and, thus, for the sub-wavelength near-field imaging. The
sheets are placed in free space so that they are parallel and separated by a
certain distance. Due to interaction of the resonating surface modes
(polaritons) of the sheets an exponential growth in the amplitude of an
evanescent plane wave coming through the system can be achieved. This effect
was predicted earlier for backward-wave (double-negative or Veselago) slab
lenses. The alternative system considered here is proved to be realizable at
microwaves by grids or arrays of resonant particles. The necessary
electromagnetic properties of the resonating grids and the particles are
investigated and established. Theoretical results are supported by microwave
experiments that demonstrate amplification of evanescent modes.",0311089v1
2004-07-15,Superconducting Phase Qubit Coupled to a Nanomechanical Resonator: Beyond the Rotating-Wave Approximation,"We consider a simple model of a Josephson junction phase qubit coupled to a
solid-state nanoelectromechanical resonator. This and many related
qubit-resonator models are analogous to an atom in an electromagnetic cavity.
When the systems are weakly coupled and nearly resonant, the dynamics is
accurately described by the rotating-wave approximation (RWA) or the
Jaynes-Cummings model of quantum optics. However, the desire to develop faster
quantum-information-processing protocols necessitates approximate, yet analytic
descriptions that are valid for more strongly coupled qubit-resonator systems.
Here we present a simple theoretical technique, using a basis of dressed
states, to perturbatively account for the leading-order corrections to the RWA.
By comparison with exact numerical results, we demonstrate that the method is
accurate for moderately strong coupling, and provides a useful theoretical tool
for describing fast quantum information processing. The method applies to any
quantum two-level system linearly coupled to a harmonic oscillator or
single-mode boson field.",0407106v1
2004-07-16,Rigorous derivation of coherent resonant tunneling time and velocity in finite periodic systems,"The velocity $v_{res}$ of resonant tunneling electrons in finite periodic
structures is analytically calculated in two ways. The first method is based on
the fact that a transmission of unity leads to a coincidence of all still
competing tunneling time definitions. Thus, having an indisputable resonant
tunneling time $\tau_{res},$ we apply the natural definition
$v_{res}=L/\tau_{res}$ to calculate the velocity. For the second method we
combine Bloch's theorem with the transfer matrix approach to decompose the wave
function into two Bloch waves. Then the expectation value of the velocity is
calculated. Both different approaches lead to the same result, showing their
physical equivalence. The obtained resonant tunneling velocity $v_{res}$ is
smaller or equal to the group velocity times the magnitude of the complex
transmission amplitude of the unit cell. Only at energies where the unit cell
of the periodic structure has a transmission of unity $v_{res}$ equals the
group velocity. Numerical calculations for a GaAs/AlGaAs superlattice are
performed. For typical parameters the resonant velocity is below one third of
the group velocity.",0407134v1
2007-06-26,Resonant and Near-Resonant Internal Wave Interactions,"We report evaluations of a resonant kinetic equation that suggest the slow
time evolution of the Garrett and Munk spectrum is {\em not}, in fact, slow.
Instead nonlinear transfers lead to evolution time scales that are smaller than
one wave period at high vertical wavenumber. Such values of the transfer rates
are inconsistent with conventional wisdom that regards the Garrett and Munk
spectrum as an approximate stationary state and puts the self-consistency of a
resonant kinetic equation at a serious risk. We explore possible reasons for
and resolutions of this paradox. Inclusion of near-resonant interactions
decreases the rate at which the spectrum evolves. This leads to improved
self-consistency of the kinetic equation.",0706.3712v4
2008-03-01,Spatial coherence resonance on diffusive and small-world networks of Hodgkin-Huxley neurons,"Spatial coherence resonance in a spatially extended system that is locally
modeled by Hodgkin-Huxley (HH) neurons is studied in this paper. We focus on
the ability of additive temporally and spatially uncorrelated Gaussian noise to
extract a particular spatial frequency of excitatory waves in the medium,
whereby examining also the impact of diffusive and small-world network topology
determining the interactions amongst coupled HH neurons. We show that there
exists an intermediate noise intensity that is able to extract a characteristic
spatial frequency of the system in a resonant manner provided the latter is
diffusively coupled, thus indicating the existence of spatial coherence
resonance. However, as the diffusive topology of the medium is relaxed via the
introduction of shortcut links introducing small-world properties amongst
coupled HH neurons, the ability of additive Gaussian noise to evoke ordered
excitatory waves deteriorates rather spectacularly, leading to the decoherence
of the spatial dynamics and with it related absence of spatial coherence
resonance. In particular, already a minute fraction of shortcut links suffices
to substantially disrupt coherent pattern formation in the examined system.",0803.0070v1
2011-10-19,Continuous-wave Cascaded-Harmonic Generation and Multi-Photon Raman Lasing in Lithium Niobate Whispering-Gallery Resonators,"We report experimental demonstration of continuous-wave cascaded-harmonic
generation and Raman lasing in a millimeter-scale lithium niobate
whispering-gallery resonator pumped at a telecommunication-compatible infrared
wavelength. Intensity enhancement through multiple recirculations in the
whispering-gallery resonator and quasi phase-matching through a nonuniform
crystal poling enable simultaneous cascaded-harmonic generation up to the
fourth-harmonic accompanied by stimulated Raman, two-photon, three-photon, and
four-photon Raman scattering corresponding the molecular vibrational
wavenumbers 632 cm-1 and 255 cm-1 in z-cut lithium niobate at pump power levels
as low as 200mW. We demonstrate simultaneous cascaded-harmonic generation and
Raman lasing by observing the spectrum of the scattered light from the
resonator and by capturing the image of the decoupled light from the resonator
on a color CCD camera.",1110.4394v1
2012-02-21,Extremely Low-Loss Acoustic Phonons in a Quartz Bulk Acoustic Wave Resonator at Millikelvin Temperature,"Low-loss, high frequency acoustic resonators cooled to millikelvin
temperatures are a topic of great interest for application to hybrid quantum
systems. When cooled to 20 mK, we show that resonant acoustic phonon modes in a
Bulk Acoustic Wave (BAW) quartz resonator demonstrate exceptionally low loss
(with $Q$-factors of order billions) at frequencies of 15.6 and 65.4 MHz, with
a maximum $f.Q$ product of 7.8$\times10^{16}$ Hz. Given this result, we show
that the $Q$-factor in such devices near the quantum ground state can be four
orders of magnitude better than previously attained. Such resonators possess
the low losses crucial for electromagnetic cooling to the phonon ground state,
and the possibility of long coherence and interaction times of a few seconds,
allowing multiple quantum gate operations.",1202.4556v2
2012-04-24,Parametric four-wave mixing toolbox for superconducting resonators,"We study a superconducting circuit that can act as a toolbox to generate
various Bogoliubov-linear and nonlinear quantum operations on the microwave
photon modes of superconducting resonators within one single circuit. The
quantum operations are generated by exploring dispersive four-wave mixing (FWM)
processes involving the resonator modes. Different FWM geometries can be
realized by adjusting the circuit parameters and by applying appropriate
microwave drivings. We illustrate this scheme using a circuit made of two
superconducting qubits that couple with each other. Each qubit couples with one
superconducting resonator. We also discuss main quantum errors in this scheme
and study the fidelity of the quantum operations by numerical simulation. Our
scheme provides a practical approach to realize quantum information protocols
on superconducting resonators.",1204.5450v2
2013-03-04,Exact conservation and breaking of pseudospin symmetry in single particle resonant states,"In this contribution we present some results on the study of pseudospin
symmetry (PSS) in single particle resonant states. The PSS is a relativistic
dynamical symmetry connected with the small component of the nucleon Dirac wave
function. Many efforts have been made to study this symmetry in bound states.
We recently gave a rigorous justification of the PSS in single particle
resonant states by examining the zeros of Jost functions corresponding to the
small components of the radial Dirac wave functions and phase shifts of
continuum states [1, Phys. Rev. Lett. 109 (2012) 072501]. We have shown that
the PSS in single particle resonant states in nuclei is conserved when the
attractive scalar and repulsive vector potentials have the same magnitude but
opposite sign. Examples of exact conservation and breaking of this symmetry in
single particle resonances are given for spherical square-well and Woods-Saxon
potentials.",1303.0630v1
2013-03-21,Resonance phenomena in the interaction of a many-photon wave packet and a qubit,"We demonstrate that a highly excited quantum electromagnetic mode strongly
interacting with a single qubit exhibits several distinct resonances in
addition to the Bloch-Siegert resonance condition that arises in the
interaction with classical radiation. The resonance phenomena are associated
with non-classical effects: Collapse of Rabi oscillations, splitting of the
photon wave packet, and field-qubit entanglement. The analysis is based on a
semiclassical phase-space flow of 2-by-2 matrices and becomes exact when the
photon number tends to infinity. The flow equations are solved perturbatively
and numerically, showing that the resonant detuning of the field and qubit
frequencies lie on two branches in the leading order, that further split into
distinct curves in higher orders.",1303.5256v1
2014-04-24,The composite nature of the $Λ(1520)$ resonance,"Recently, the Weinberg compositeness condition of a bound state was
generalized to account for resonant states and higher partial waves. We apply
this extension to the case of the $\Lambda(1520)$ resonance and quantify the
weight of the meson-baryon components in contrast to other possible genuine
building blocks. This resonance was theoretically obtained from a coupled
channels analysis using the s-waves $\pi\Sigma^*$, $K\Xi^*$ and the d-waves
$\bar{K}N$ and $\pi\Sigma$ channels applying the techniques of the chiral
unitary approach. We obtain that this resonance is essentially dynamically
generated from these meson-baryon channels, leaving room for only $15 \%$
weight of other kind of components into its wave function.",1404.6128v2
2014-10-03,Vortices at the magnetic equator generated by hybrid Alfven resonant waves,"We performed three-dimensional magnetohydrodynamic simulations of shear
Alfven waves in a full field line system with magnetosphere-ionosphere coupling
and plasma non-uniformities. Feedback instability of the Alfven resonant modes
showed various nonlinear features under the field line cavities: i) a secondary
flow shear instability occurs at the magnetic equator, ii) trapping of the
ionospheric Alfven resonant modes facilitates deformation of field-aligned
current structures, and iii) hybrid Alfven resonant modes grow to cause
vortices and magnetic oscillations around the magnetic equator. Essential
features in the initial brightening of auroral arc at substorm onsets could be
explained by the dynamics of Alfven resonant modes, which are the nature of the
field line system responding to a background rapid change.",1410.0764v1
2014-12-05,Resonant and non-resonant whistlers-particle interaction in the radiation belts,"We study the wave-particle interactions between lower band chorus whistlers
and an anisotropic tenuous population of relativistic electrons. We present the
first direct comparison of first-principle Particle-in-Cell (PIC) simulations
with a quasi-linear diffusion code, in this context. In the PIC approach, the
waves are self-consistently generated by a temperature anisotropy instability
that quickly saturates and relaxes the system towards marginal stability. We
show that the quasi-linear diffusion and PIC results have significant
quantitative mismatch in regions of energy/pitch angle where the resonance
condition is not satisfied. Moreover, for pitch angles close to the loss cone
the diffusion code overestimates the scattering, particularly at low energies.
This suggest that higher order nonlinear theories should be taken in
consideration in order to capture non-resonant interactions, resonance
broadening, and to account for scattering at angles close to $90^\circ$.",1412.2008v1
2015-10-20,Complex contact-based dynamics of microsphere monolayers revealed by resonant attenuation of surface acoustic waves,"Contact-based vibrations play a critical role in the dynamics of granular
materials. Significant insights into vibrational granular dynamics have been
obtained with reduced-dimensional systems containing macroscale particles. We
study contact-based vibrations of a two-dimensional monolayer of micron-sized
spheres on a solid substrate. Measurements of the resonant attenuation of
laser-generated surface acoustic waves reveal three collective vibrational
modes involving both displacements and rotations of the microspheres. To
identify the modes, we tune the interparticle stiffness, which shifts the
frequency of the horizontal-rotational resonances while leaving the vertical
resonance unaffected. From the measured contact resonance frequencies we
determine both particle-substrate and interparticle contact stiffnesses and
find that the former is an order of magnitude larger than the latter. This
study paves the way for investigating complex contact-based dynamics of
microgranular media, demonstrates a novel acoustic metamaterial, and yields a
new approach to studying micro- to nanoscale contact mechanics in multiparticle
networks.",1510.05975v1
2016-01-06,Properties of wideband resonant reflectors under fully conical light incidence,"Applying numerical modeling coupled with experiments, we investigate the
properties of wideband resonant reflectors under fully conical light incidence.
We show that the wave vectors pertinent to resonant first-order diffraction
under fully conical mounting vary less with incident angle than those
associated with reflectors in classical mounting. Therefore, as the evanescent
diffracted waves drive the leaky modes responsible for the resonance effects,
fully-conical mounting imbues reflectors with larger angular tolerance than
their classical counterparts. We quantify the angular-spectral performance of
representative resonant wideband reflectors in conic and classic mounts by
numerical calculations with improved spectra found for fully conic incidence.
Moreover, these predictions are verified experimentally for wideband reflectors
fashioned in crystalline and amorphous silicon in distinct spectral regions
spanning the 1200-1600-nm and 1600-2400-nm spectral bands. These results will
be useful in various applications demanding wideband reflectors that are
efficient and materially sparse.",1601.01333v1
2017-09-21,Limitations of rotating-wave approximation in magnetic resonance: Characterization and elimination of the Bloch-Siegert shift in magneto-optics,"We present investigations of radio-frequency resonances observed in a
rubidium vapor. With measurements of a systematic shift of radio-frequency
resonances, induced by an off-resonance component of an oscillating field (the
Bloch-Siegert shift), we demonstrate limitations of the rotating-wave
approximation. Experimental results are supported with numerical calculations,
reproducing all features of the observed signals. Based on the studies, we
develop experimental scheme free from the problem. By liberating the
measurements from a systematic error (the resonance shift), the new approach
will increase accuracy of spectroscopic measurements and magnetic-field
detection.",1709.07194v3
2017-12-28,Ultrathin wave plates based on bi-resonant silicon Huygens' metasurfaces,"An all-dielectric Huygens metasurface supporting electric and magnetic
resonances is a promising platform for a variety of optical applications that
require a combination of extremely high transmission and broad-range control of
the phase of the transmitted light. A highly efficient wave plate is one
example of such an application. In combination with high spectral selectivity
and strong optical energy concentration, such phase plates are desirable for
precision sensing and high efficiency nonlinear optics. We propose a novel
approach to realizing such ultra-thin optical plates: an anisotropic
Fano-resonant optical metasurface (AFROM) employing the combination of a
spectrally sharp electric and a relatively broadband magnetic resonance. The
phase shift coverage approaching 2{\pi} is achieved through judicious choice of
the geometric parameters of a complex unit cell. A new methodology based on
eigenvalue simulations of leaky magnetic/electric resonances enables rapid
computational design of such metasurfaces.",1712.10064v1
2018-09-14,Topological Fano Resonances,"The Fano resonance is a widespread wave scattering phenomenon associated with
a peculiar asymmetric and ultra-sharp line shape, which has found applications
in a large variety of prominent optical devices. While its substantial
sensitivity to geometrical and environmental changes makes it the cornerstone
of efficient sensors, it also renders the practical realization of Fano-based
systems extremely challenging. Here, we introduce the concept of topological
Fano resonance, whose ultra-sharp asymmetric line shape is guaranteed by design
and protected against geometrical imperfections, yet remaining sensitive to
external parameters. We report the experimental observation of such resonances
in an acoustic system, and demonstrate their inherent robustness to geometrical
disorder. Such topologically-protected Fano resonances, which can also be found
in microwave, optical and plasmonic systems, open up exciting frontiers for the
generation of various reliable wave-based devices including low-threshold
lasers, perfect absorbers, ultrafast switches or modulators, and highly
accurate interferometers, by circumventing the performance degradations caused
by inadvertent fabrication flaws.",1809.05389v1
2019-11-22,Resonant field enhancement near bound states in the continuum on periodic structures,"On periodic structures sandwiched between two homogeneous media, a bound
state in the continuum (BIC) is a guided Bloch mode with a frequency within the
radiation continuum. BICs are useful, since they give rise to high
quality-factor ($Q$-factor) resonances that enhance local fields for
diffraction problems with given incident waves. For any BIC on a periodic
structure, there is always a surrounding family of resonant modes with
$Q$-factors approaching infinity. We analyze field enhancement around BICs
using analytic and numerical methods. Based on a perturbation method, we show
that field enhancement is proportional to the square-root of the $Q$-factor,
and it depends on the adjoint resonant mode and its coupling efficiency with
incident waves. Numerical results are presented to show different asymptotic
relations between the field enhancement and the Bloch wavevector for different
BICs. Our study provides a useful guideline for applications relying on
resonant enhancement of local fields.",1911.10058v1
2019-06-18,Atomic Resonant Single-Mode Squeezed Light from Four-Wave Mixing through Feedforward,"Squeezed states of light have received renewed attention due to their
applicability to quantum-enhanced sensing. To take full advantage of their
reduced noise properties to enhance atomic-based sensors, it is necessary to
generate narrowband near or on atomic resonance single-mode squeezed states of
light. We have previously generated bright two-mode squeezed states of light,
or twin beams, that can be tuned to resonance with the D1 line of $^{87}$Rb
with a non-degenerate four-wave mixing (FWM) process in a double-lambda
configuration in a $^{85}$Rb vapor cell. Here we report on the use of
feedforward to transfer the amplitude quantum correlations present in the twin
beams to a single beam for the generation of single-mode amplitude squeezed
light. With this technique we obtain a single-mode squeezed state with a
squeezing level of $-2.9\pm0.1$ dB when it is tuned off-resonance and a level
of $-2.0\pm 0.1$ dB when it is tuned on resonance with the D1 $F=2$ to $F'=2$
transition of $^{87}$Rb.",1906.07666v1
2017-10-12,Resonant Mode Conversion of the Second Sound to the First Sound in Liquid Helium II,"The experimentally observed disappearance below T = 0.5K of the second sound
in liquid He II as a separate wave mode and its subsequent propagation at the
speed of the first sound (Peshkov [3]) may be interpreted as a resonant mode
conversion of the second sound to the first sound. Near the resonant mode
coupling point T = T*, where the frequencies of the two waves become equal, the
anomalous effect of entropy changes on the first sound and density changes on
the second sound, though generally small, become significant. This leads to the
resonant mode coupling of the first sound and the second sound and forces them
to lose their identities and hence pave the way for the resonant mode
conversion of the second sound to the first sound. We give a theoretical
framework for this proposition and an estimate for the fraction of the second
sound that is mode-converted to the first sound.",1710.04593v2
2020-09-28,Metasurface Reflector with Real-Time Independent Magnitude and Phase Control,"A novel metasurface unit cell architecture is proposed to enable independent
control of the reflection magnitude and phase at a desired operation frequency,
while maintaining linear polarization of the incoming fields. The proposed
structure is based on a coupled-resonator configuration where a Dipole Ring
Resonator (DRR) is loaded with a tunable lumped resistive element (e.g. PIN
diode) and Split Ring Resonator (SRR) loaded with a lumped tunable capacitor
(e.g. varactor diode), are interleaved. The surface is next operated around one
of the coupled resonant frequency, where an independent tuning of the lumped
capacitance and resistance elements enable a wide coverage of reflection
amplitude-phase, which is significantly larger than what would have been
achievable using a single resonator configuration. An insightful equivalent
circuit model is further developed for investigating the amplitude-phase
characteristics of a uniform surface as a function of variable resistance and
capacitance, which is next confirmed using full-wave simulations. Finally,
using a variety of full-wave examples, the usefulness of simultaneous and
independent amplitude-phase control is demonstrated, including cases of
variable pattern gain with beam tilting and multi-beam pattern realization,
which otherwise would not be possible using either amplitude or phase control
only.",2009.13369v1
2008-06-26,Electromagnetically-Induced-Transparency-Like Effect in the Degenerate Triple-Resonant Optical Parametric Amplifier,"We investigate experimentally the absorptive and dispersive properties of
triple-resonant optical parametric amplifier OPA for the degenerate subharmonic
field. In the experiment, the subharmonic field is utilized as the probe field
and the harmonic wave as the pump field. We demonstrate that EIT-like effect
can be simulated in the triple-resonant OPA when the cavity line-width for the
harmonic wave is narrower than that for the subharmonic field. However, this
phenomenon can not be observed in a double-resonant OPA. The narrow
transparency window appears in the reflected field. Especially, in the measured
dispersive spectra of triple-resonant OPA, a very steep variation of the
dispersive profile of the subharmonic field is observed, which can result in a
slow light as that observed in atomic EIT medium.",0806.4218v1
2019-01-24,Rapid falling of an orbiting moon to its parent planet due to tidal-seismic resonance,"Tidal force plays an important role in the evolution of the planet-moon
system. The tidal force of a moon can excite seismic waves in the planet it is
orbiting. A tidal-seismic resonance is expected when a tidal force frequency
matches a free-oscillation frequency of the planet. Here we show that when the
moon is close to the planet, the tidal-seismic resonance can cause
large-amplitude seismic waves, which can change the shape of the planet and in
turn exert a negative torque on the moon to cause it to fall rapidly toward the
planet. We postulate that the tidal-seismic resonance may be an important
mechanism which can accelerate planet accretion process. On the other hand,
tidal-seismic resonance effect can also be used to interrogate planet interior
by long term tracking of the orbital change of the moon.",1901.08561v1
2019-04-18,On spurious solutions encountered in Helmholtz scattering resonance computations in R^d with applications to nano-photonics and acoustics,"In this paper, we consider a sorting scheme for potentially spurious
scattering resonant pairs in one- and two-dimensional electromagnetic problems
and in three-dimensional acoustic problems. The novel sorting scheme is based
on a Lippmann-Schwinger type of volume integral equation and can, therefore, be
applied to structures with graded materials as well as to configurations
including piece-wise constant material properties. For TM/TE polarized
electromagnetic waves and for acoustic waves, we compute first approximations
of scattering resonances with finite elements. Then, we apply the novel sorting
scheme to the computed eigenpairs and use it to mark potentially spurious
solutions in electromagnetic and acoustic scattering resonances computations at
a low computational cost. Several test cases with Drude-Lorentz dielectric
resonators as well as with graded material properties are considered.",1904.08812v3
2019-04-20,Hybridization-induced resonances with high quality factor in a plasmonic concentric ring-disk nanocavity,"Plasmonic resonators have drawn more attention due to the ability to confine
light into subwavelength scale. However, they always suffer from a low quality
(Q) factor owing to the intrinsic loss of metal. Here, we numerically propose a
plasmonic resonator with ultra-high Q factor based on plasmonic
metal-insulator-metal (MIM) waveguide structures. The resonator consists of a
disk cavity surrounded by a concentric ring cavity, possessing an ultra-small
volume. Arising from the plasmon hybridization between plasmon modes in the
disk and ring cavity, the induced bonding hybridized modes have ultra-narrow
full wave at half maximum (FWHM) as well as ultra-high Q factors. The FWHM can
be nearly 1 nm and Q factor can be more than 400. Furthermore, such device can
act as a refractive index sensor with ultra-high figure of merit (FOM). This
work provides a novel approach to design plasmonic high-Q-factor resonators,
and has potential on-chip applications such as filters, sensors and nanolasers.",1904.09437v1
2019-08-12,Triple-Poles Complementary Split Ring Resonator for Sensing Diabetics Glucose Levels at cm-Band,"Microwave sensors are very promising for sensing the blood glucose levels
non-invasively for their non-ionizing nature, miniaturized sizing, and low
health risks for diabetics. All these features offer the possibility for
realizing a portable non-invasive glucose sensor for monitoring glucose levels
in real time. In this article, we propose a triple poles complementary split
ring resonator (CSRR) produced on a FR4 substrate in microstrip technology in
the cm-wave band (1-6 GHz). The proposed bio-sensor can detect the small
variations in the dielectric properties (relative permittivity and dielectric
losses) of glucose in the blood mimicking aqueous solutions due their intense
interaction with the electromagnetic field at harmonic resonances. The
resonator exhibits higher sensitivity performance at the different resonances
compared to the single and double-poles counterparts as demonstrated by
simulations in a 3D full-wave EM solver.",1908.07407v1
2019-12-10,AlN Combined Overtone Resonators for the 5G mmWave Spectrum,"This work presents a new acoustic MEMS resonator technology, dubbed Aluminum
Nitride (AlN) Combined Overtone Resonator (COR), capable of addressing the
filter requirements for the 5G mmWave spectrum in the 6-40GHz range. The COR
exploits the multimodal excitation of two higher-order Lamb waves (2nd and 3rd
order Asymmetrical Lamb Waves) in a suspended thin-film AlN plate to transduce
a 2-dimensional vibration mode with high electromechanical coupling coefficient
kt2 (up to 1.9%) and quality factor Q >1100 at twice the frequency of a
fundamental thickness-extensional mode in the same structure. Analytical and
finite-element method (FEM) models are developed to describe the working
principle of the COR technology and predict the achievable kt2, Q and
lithographic frequency tunability. An 8.8 GHz COR prototype was fabricated
showing a high kt2~0.3% (using a simple top-electrode-only configuration with a
2-mask process) and a groundbreaking Q~1100 which is the highest ever achieved
among piezoelectric resonators above 6 GHz. The f-Q product ~1x10e13 is the
highest among all demonstrated piezoelectric resonators with metallic coverage
>50%. Additionally, the capability of the COR technology to deliver contiguous
filters with bandwidths between 355 and 592 MHz (aggregated BW>2GHz) in the
mmWave spectrum, with relaxed lithographic requirements, is demonstrated by
FEM.",1912.04515v1
2020-01-14,Experimental realization of optimal energy storage in resonators embedded in scattering media,"The ability to enhance light-matter interactions by increasing the energy
stored in optical resonators is inherently dependent on their coupling to the
incident wavefront. In practice, weak coupling may result from resonators'
irregular shapes and/or the scrambling of waves in the surrounding scattering
environment. Here, we present a non-invasive wavefront shaping technique
providing optimal coupling to resonators. The coherent control of the incident
wavefront relies on the lengthening of delay times of waves efficiently
exciting the resonator. We demonstrate our concept in microwave experiments by
injecting in-situ optimal wavefronts that maximize the energy stored in
multiple high-permittivity dielectric scatterers and extended leaky cavities
embedded in a complex environment. We expect our framework to find important
applications in the enhancement of light-matter interactions in photonic
materials as well as to enhance energy harvesting.",2001.04658v1
2020-10-23,Resonances in hyperbolic dynamics,"The study of wave propagation outside bounded obstacles uncovers the
existence of resonances for the Laplace operator, which are complex-valued
generalized eigenvalues, relevant to estimate the long time asymptotics of the
wave. In order to understand distribution of these resonances at high
frequency, we employ semiclassical tools, which leads to considering the
classical scattering problem, and in particular the set of trapped
trajectories. We focus on ""chaotic"" situations, where this set is a hyperbolic
repeller, generally with a fractal geometry. In this context, we derive fractal
Weyl upper bounds for the resonance counting; we also obtain dynamical criteria
ensuring the presence of a resonance gap. We also address situations where the
trapped set is a normally hyperbolic submanifold, a case which can help
analyzing the long time properties of (classical) Anosov contact flows through
semiclassical methods.",2010.12385v1
2022-05-18,Graviton to Photon Conversion via Parametric Resonance,"We study the parametric resonance excitation of the electromagnetic field by
a gravitational wave. We show that there is narrow band resonance. For an
electromagnetic field in the vacuum the resonance occurs only in the second
band, and its strength is thus suppressed by two powers of amplitude of the
gravitational wave. On the other hand, in the case of an electromagnetic field
in a medium with the speed of light smaller than 1 (in natural units), there is
a band of Fourier modes which undergo resonance in the first band.",2205.08767v3
2022-10-15,Elastic Wave Scattering off a Single and Double Array of Periodic Defects,"Elastic waves scattering off a periodic single and double array of thin
cylindrical defects is considered for isotropic materials. An analytical
expression for the scattering matrix is obtained by means of the
Lippmann-Schwinger formalism and analyzed in the long wavelength limit using
Schloemilch series in order to obtain explicit expressions for the poles of the
scattering matrix. The latter is then used to prove that for a specific curve
in the space of physical and geometric parameters, the scattering is dominated
by resonances, and the width of the resonances in the shear mode parallel to
the cylinders has a global minimum in parameter space. This a feature is not
observed in similar photonic or acoustic systems. The resonances in shear and
compression modes that are coupled in the plane perpendicular to the cylinders
due to the normal traction boundary condition are studied for the double array.
The analytical dependence of the width of these resonances on physical and
geometrical parameters is exploited to prove the existence of resonances with
the vanishing width, known as Bound States in the Continuum (BSC). Spectral
characteristics of BSC are explicitly found in terms of the Bloch phase and
group velocities of elastic modes.",2210.08177v1
2022-11-12,Broadband Four-Wave Mixing Enhanced by Plasmonic Surface Lattice Resonance and Localized Surface Plasmon Resonance in an Azimuthally Chirped Grating,"Plasmonic enhancement of nonlinear light-matter interaction can be achieved
via dedicated optimization of resonant plasmonic modes that are spectrally
matched to the different wavelengths involved in the particular nonlinear
optical process. In this work, we investigate the generation and enhancement of
broadband four-wave mixing (FWM) in a plasmonic azimuthally chirped grating
(ACG). The azimuthally varying grating periodicity in an ACG offers a
well-defined channel to mediate the near field and the far field over a broad
range of wavelengths. However, the particular mechanism responsible for field
enhancement in such a platform depends on the interplay between the effects
manifested by both the groove geometry and the grating's periodicity. This work
delineates the collective contribution of groove geometry-dependent localized
surface plasmon resonance (LSPR) and periodicity-dependent plasmonic surface
lattice resonance (PSLR) over a broad range of wavelengths to bring into effect
the enhancement of broadband FWM in an ACG.",2211.06647v1
2022-12-05,Explanation of Y(4630) as hadronic resonant state,"After Y(4630) is discovered, theorists have given various explanations. We
find that if Y(4630) is interpreted as the D-wave resonant state of $\Lambda_c
\bar {\Lambda}_c$ system, the particle mass, decay width and all quantum
numbers are consistent with experimental observations. We use the Bonn
approximation to get the interaction potential of one boson exchange model,
then extend the complex scaling method (CSM) to calculate the bound and
resonant states. The results indicate that the $\Lambda_c \bar{\Lambda}_c$
system can form not only the bound state of S wave, but also the resonant state
of the high angular momentum, and the $^3D_1$ wave resonant state can explain
the structure of Y(4630) very well.",2212.02218v1
2023-04-05,Multiphoton resonance band and Bloch-Siegert shift in a bichromatically driven qubit,"We study the resonance and dynamics of a qubit exposed to a strong aperiodic
bichromatic field by using a periodic counter-rotating hybridized rotating wave
(CHRW) Hamiltonian, which is derived from the original Hamiltonian with the
unitary transformations under a reasonable approximation and enables the
application of the Floquet theory. It is found that the consistency between the
CHRW results and numerically exact generalized-Floquet-theory (GFT) results in
the valid regime of the former while the widely used rotating-wave
approximation (RWA) breaks down. We illustrate that the resonance exhibits band
structure and the Bloch-Siegert shifts induced by the counter-rotating
couplings of the bichromatic field become notable at the multiphoton resonance
band. In addition, the CHRW method is found to have a great advantage of
efficiency over the GFT approach particularly in the low beat-frequency case
where the latter converges very slowly. The present CHRW method provides a
highly efficient way to calculate the resonance frequency incorporating the
Bloch-Siegert shift and provides insights into the effects of the
counter-rotating couplings of the bichromatic field in the strong-driving
regimes.",2304.02676v1
2023-05-03,$Σ$ Resonances from a Neural Network-based Partial Wave Analysis on $K^-p$ Scattering,"We implement a convolutional neural network to study the $\Sigma$ hyperons
using experimental data of the $K^-p\to\pi^0\Lambda$ reaction. The averaged
accuracy of the NN models in resolving resonances on the test data sets is
${\rm 98.5\%}$, ${\rm 94.8\%}$ and ${\rm 82.5\%}$ for one-, two- and
three-additional-resonance case. We find that the three most significant
resonances are $1/2^+$, $3/2^+$ and $3/2^-$ states with mass being ${\rm
1.62(11)~GeV}$, ${\rm 1.72(6)~GeV}$ and ${\rm 1.61(9)~GeV}$, and probability
being $\rm 100(3)\%$, $\rm 72(24)\%$ and $\rm 98(52)\%$, respectively, where
the errors mostly come from the uncertainties of the experimental data. Our
results support the three-star $\Sigma(1660)1/2^+$, the one-star
$\Sigma(1780)3/2^+$ and the one-star $\Sigma(1580)3/2^-$ in PDG. The ability of
giving quantitative probabilities in resonance resolving and numerical
stability make NN potentially a life-changing tool in baryon partial wave
analysis, and this approach can be easily extended to accommodate other
theoretical models and/or to include more experimental data.",2305.01852v1
2023-06-30,Controlling photons by phonons via giant atom in a waveguide QED setup,"We investigate the single photon scattering in a phonon-photon hybrid system
in the waveguide QED scheme. In our consideration, an artificial giant atom,
which is dressed by the phonons in a surface acoustic wave resonator, interacts
with a coupled resonator waveguide (CRW) nonlocally via two connecting sites.
Together with the interference effect by the nonlocal coupling, the phonon
serves as a controller to the transport of the photon in the waveguide. On the
one hand, the coupling strength between the giant atom and the surface acoustic
wave resonator modulates the width of the transmission valley or window in the
near resonant regime. On the other hand, the two reflective peaks induced by
the Rabi splitting degrade into a single one when the giant atom is large
detuned from the surface acoustic resonator, which implies an effective
dispersive coupling. Our study paves the way for the potential application of
giant atoms in the hybrid system.",2306.17444v1
2023-09-06,Millimeter Wave Thin-Film Bulk Acoustic Resonator in Sputtered Scandium Aluminum Nitride,"This work reports a millimeter wave (mmWave) thin-film bulk acoustic
resonator (FBAR) in sputtered scandium aluminum nitride (ScAlN). This paper
identifies challenges of frequency scaling sputtered ScAlN into mmWave and
proposes a stack and new fabrication procedure with a sputtered Sc0.3Al0.7N on
Al on Si carrier wafer. The resonator achieves electromechanical coupling (k2)
of 7.0% and quality factor (Q) of 62 for the first-order symmetric (S1) mode at
21.4 GHz, along with k2 of 4.0% and Q of 19 for the third-order symmetric (S3)
mode at 55.4 GHz, showing higher figures of merit (FoM, k2xQ) than reported
AlN/ScAlN-based mmWave acoustic resonators. The ScAlN quality is identified by
transmission electron microscopy (TEM) and X-ray diffraction (XRD), identifying
the bottlenecks in the existing piezoelectric-metal stack. Further improvement
of ScAlN/AlN-based mmWave acoustic resonators calls for better crystalline
quality from improved thin-film deposition methods.",2309.03135v1
2023-11-09,38.7 GHz Thin Film Lithium Niobate Acoustic Filter,"In this work, a 38.7 GHz acoustic wave ladder filter exhibiting insertion
loss (IL) of 5.63 dB and 3-dB fractional bandwidth (FBW) of 17.6% is
demonstrated, pushing the frequency limits of thin-film piezoelectric acoustic
filter technology. The filter achieves operating frequency up to 5G millimeter
wave (mmWave) frequency range 2 (FR2) bands, by thinning thin-film LiNbO3
resonators to sub-50 nm thickness. The high electromechanical coupling (k2) and
quality factor (Q) of first-order antisymmetric (A1) mode resonators in 128
Y-cut lithium niobate (LiNbO3) collectively enable the first acoustic filters
at mmWave. The key design consideration of electromagnetic (EM) resonances in
interdigitated transducers (IDT) is addressed and mitigated. These results
indicate that thin-film piezoelectric resonators could be pushed to 5G FR2
bands. Further performance enhancement and frequency scaling calls for better
resonator technologies and EM-acoustic filter co-design.",2311.05712v1
2023-11-28,Gravitational Wave Detection and Low-Noise Sapphire Oscillators,"This thesis describes the development of an ultra-low noise sapphire
resonator oscillator that is tunable over X-band. While undertaking this task
the author has explained some interesting and very useful phenomena in regards
to the design and understanding of multi-mode resonant cavities and
oscillators. The oscillator was constructed to operate as the pump oscillator
in the superconducting parametric transducer system, attached to a 1.5-tonne
niobium resonant bar gravitational wave detector. The effects of incorporating
the pump oscillator with the parametric transducer and resonant bar system are
analyzed to enable prediction of the detector sensitivity. The detector was the
first massive precision optomechanical system ever built. With the resurgence
in interest in resonant detectors, this thesis has important work on multi-mode
acoustic systems, coupled to a highly sensitive parametric transducer relevant
for many fields of research today.",2311.16426v1
2004-06-13,"Condensation, excitation, pairing, and superfluid density in high-$T_{c}$ superconductors: magnetic resonance mode as a roton analogue and a possible spin-mediated pairing","To find out a primary determing factor of $T_{c}$ and a pairing mechanism in
high-$T_{c}$ cuprates, we combine the muon spin relaxation results on
$n_{s}/m^{*}$ (superconducting carrier density / effective mass), accumulated
over the last 15 years, with the results from neutron and Raman scattering,
STM, specific heat, Nernst effect and ARPES measurements. We identify the
neutron magnetic resonance mode as an analogue of roton minimum in the
superfluid $^{4}$He, and argue that $n_{s}/m^{*}$ and the resonance mode energy
$\hbar\omega_{res}$ play a primary role in determining $T_{c}$ in the
underdoped region. We propose a picture that roton-like excitations in the
cuprates appear as a coupled mode, which has the resonance mode for spin and
charge responses at different momentum transfers but the same energy transfers,
as detected respectively, by the neutron S=1 mode and the Raman S=0 A1$_{g}$
mode. We shall call this as the ``hybrid spin/charge roton''. After discussing
the role of dimensionality in condensation, we propose a generic phase diagram
of the cuprates with spatial phase separation in the overdoped region as a
special case of the BE-BCS crossover conjecture where the superconducting
coupling is lost rapidly in the overdoped region. Using a microscopic model of
charge motion resonating with antiferomagnetic spin fluctuations, we propose a
possibility that the hybrid spin/charge roton and higher-energy spin
fluctuations mediate the superconducting pairing. In this model, the resonance
modes can be viewed as a meson-analogue and the ``dome'' shape of the phase
diagram can be understood as a natural consequence of departure from the
competing Mott insulator ground state via carrier doping.",0406301v1
2011-07-01,Local Runup Amplification By Resonant Wave Interactions,"Until now the analysis of long wave runup on a plane beach has been focused
on finding its maximum value, failing to capture the existence of resonant
regimes. One-dimensional numerical simulations in the framework of the
Nonlinear Shallow Water Equations (NSWE) are used to investigate the Boundary
Value Problem (BVP) for plane and non-trivial beaches. Monochromatic waves, as
well as virtual wave-gage recordings from real tsunami simulations, are used as
forcing conditions to the BVP. Resonant phenomena between the incident
wavelength and the beach slope are found to occur, which result in enhanced
runup of non-leading waves. The evolution of energy reveals the existence of a
quasi-periodic state for the case of sinusoidal waves, the energy level of
which, as well as the time required to reach that state, depend on the incident
wavelength for a given beach slope. Dispersion is found to slightly reduce the
value of maximum runup, but not to change the overall picture. Runup
amplification occurs for both leading elevation and depression waves.",1107.0304v2
2021-02-05,The role of resonant plasma instabilities in the evolution of blazar induced pair beams,"The fate of relativistic pair beams produced in the intergalactic medium by
very high energy emission from blazars remains controversial in the literature.
The possible role of resonance beam plasma instability has been studied both
analytically and numerically but no consensus has been reached. In this paper,
we thoroughly analyze the development of this type of instability. This
analysis takes into account that a highly relativistic beam loses energy only
due to interactions with the plasma waves propagating within the opening angle
of the beam (we call them parallel waves), whereas excitation of oblique waves
results merely in an angular spreading of the beam, which reduces the
instability growth rate. For parallel waves, the growth rate is a few times
larger than for oblique ones, so they grow faster than oblique waves and drain
energy from the beam before it expands. However, the specific property of
extragalactic beams is that they are extraordinarily narrow; the opening angle
is only $\Delta\theta\sim 10^{-6}-10^{-5}$. In this case, the width of the
resonance for parallel waves, $\propto\Delta\theta^2$, is too small for them to
grow in realistic conditions. We perform both analytical estimates and
numerical simulations in the quasilinear regime. These show that for
extragalactic beams, the growth of the waves is incapable of taking a
significant portion of the beam's energy. This type of instability could at
best lead to an expansion of the beam by some factor but the beam's energy
remains nearly intact.",2102.03190v1
2019-07-25,Experimental study of the non-linear saturation of the elliptical instability: inertial wave turbulence versus geostrophic turbulence,"In this paper, we present an experimental investigation of the turbulent
saturation of the flow driven by parametric resonance of inertial waves in a
rotating fluid. In our set-up, a half-meter wide ellipsoid filled with water is
brought to solid body rotation, and then undergoes sustained harmonic
modulation of its rotation rate. This triggers the exponential growth of a pair
of inertial waves via a mechanism called the libration-driven elliptical
instability. Once the saturation of this instability is reached, we observe a
turbulent state for which energy is injected into the resonant inertial waves
only. Depending on the amplitude of the rotation rate modulation, two different
saturation states are observed. At large forcing amplitudes, the saturation
flow mainly consists of a steady, geostrophic anticyclone. Its amplitude
vanishes as the forcing amplitude is decreased while remaining above the
threshold of the elliptical instability. Below this secondary transition, the
saturation flow is a superposition of inertial waves which are in weakly
non-linear resonant interaction, a state that could asymptotically lead to
inertial wave turbulence. In addition to being a first experimental observation
of a wave-dominated saturation in unstable rotating flows, the present study is
also an experimental confirmation of the model of Le Reun et al, PRL (2017) who
introduced the possibility of these two turbulent regimes. The transition
between these two regimes and their relevance to geophysical applications are
finally discussed.",1907.10907v3
2023-07-01,Existence and Instability of Standing Wave for the Two-wave Model with Quadratic Interaction,"In this paper, we establish the existence and instability of standing wave
for a system of nonlinear Schr\""{o}dinger equations arising in the two-wave
model with quadratic interaction in higher space dimensions under mass
resonance conditions. Here, we eliminate the limitation for the relationship
between complex constants $a_{1}$ and $a_{2}$ given in \cite{HOT}, and consider
arbitrary real positive constants $a_{1}$ and $a_{2}$. First of all, according
to the conservation identities for mass and energy, using the so-called virial
type estimate, we obtain that the solution for the Cauchy problem under
consideration blows up in finite time in $H^{1}(\mathbb{R}^{N})\times
H^{1}(\mathbb{R}^{N})$ with space dimension $N\geq 4$. Next, for space
dimension $N$ with $4<N<6$, we establish the existence of the ground state
solution for the elliptic equations corresponding to the nonlinear
Schr\""{o}dinger equations under the frequency and mass resonance by adopting
variational method, and further achieve the exponential decay at infinity for
the ground state. This implies the existence of standing wave for the nonlinear
Schr\""{o}dinger equaitons under consideration. Finally, by defining another
constrained minimizing problems for a pair of complex-valued functions, a
suitable manifold, referring to the characterization of the standing wave,
making appropriate scaling and adopting virial type estimate, we attain the
instability of the standing wave for the equations under frequency and mass
resonance in space dimension $N$ with $4<N<6$ by virtue of the conservations of
mass and energy. Here, we adopt the equivalence of two constrained minimizing
problems defined for pairs of complex-valued and real-valued functions $(u,v)$,
respectively, when $(u,v)$ is a pair of real-valued functions.",2307.00242v1
2024-03-05,Soliton Frequency Combs in Elastomer Membrane-Cavity Optomechanics,"Solitons, arising from nonlinear wave-matter interactions, stand out for
their intrinsic stability during wave propagation and exceptional spectral
characteristics. Their applications span diverse physical systems, including
telecommunications, atomic clocks, and precise measurements. In recent years,
significant strides have been made in developing cavity-optomechanics based
approaches to generate optical frequency combs (FCs). In this study, we present
an innovative approach, never explored before, that leverages elastomer
membrane (EM)-cavity optomechanics to achieve the generation of soliton FCs, a
highly sought-after phenomenon in the realm of nonlinear wave-matter
interactions. Our method represents a significant breakthrough due to its
streamlined simplicity, relying on a single continuous-wave (CW) laser pump and
an externally applied acoustic wave exciting an EM-cavity, which gives rise to
phonons, quantized vibrational energy states intrinsic to the elastomer's
crystalline lattice structure. The mechanical resonator and electromagnetic
cavity resonance are parametrically coupled within the microwave frequency
range, collectively orchestrate the process of soliton FCs formation with
remarkable efficiency. Numerical simulations and experimental observations
demonstrate the emergence of multiple stable localized opto-mechanical wave
packets, characterized by a narrow pulses time-domain response. Crucially, by
setting the acoustic wave frequency to match the natural frequency of the EM
resonator, the solitons' teeth are precisely spaced, and the EM's motion is
significantly amplified, giving rise to a Kerr medium. The successful
realization of optomechanical stable solitons represents a monumental
advancement with transformative potential across various fields, including
quantum computing and spectroscopy.",2403.03160v2
2011-11-14,Importance of including small body spin effects in the modelling of intermediate mass-ratio inspirals. II Accurate parameter extraction of strong sources using higher-order spin effects,"We improve the numerical kludge waveform model introduced in [1] in two ways.
We extend the equations of motion for spinning black hole binaries derived by
Saijo et al. [2] using spin-orbit and spin-spin couplings taken from
perturbative and post-Newtonian (PN) calculations at the highest order
available. We also include first-order conservative self-force corrections for
spin-orbit and spin-spin couplings, which are derived by comparison to PN
results. We generate the inspiral evolution using fluxes that include the most
recent calculations of small body spin corrections, spin-spin and spin-orbit
couplings and higher-order fits to solutions of the Teukolsky equation. Using a
simplified version of this model in [1], we found that small body spin effects
could be measured through gravitational wave observations from
intermediate-mass ratio inspirals (IMRIs) with mass ratio eta ~ 0.001, when
both binary components are rapidly rotating. In this paper we study in detail
how the spin of the small/big body affects parameter measurement using a
variety of mass and spin combinations for typical IMRIs sources. We find that
for IMRI events of a moderately rotating intermediate mass black hole (IMBH) of
ten thousand solar masses, and a rapidly rotating central supermassive black
hole (SMBH) of one million solar masses, gravitational wave observations made
with LISA at a fixed signal-to-noise ratio (SNR) of 1000 will be able to
determine the inspiralling IMBH mass, the central SMBH mass, the SMBH spin
magnitude, and the IMBH spin magnitude to within fractional errors of ~0.001,
0.001, 0.0001, and 9%, respectively. LISA can also determine the location of
the source in the sky and the SMBH spin orientation to within ~0.0001
steradians. We show that by including conservative corrections up to 2.5PN
order, systematic errors no longer dominate over statistical errors for IMRIs
with typical SNR ~1000.",1111.3243v3
2012-11-05,Tides in rotating barotropic fluid bodies: the contribution of inertial waves and the role of internal structure,"We discuss the linear response to low-frequency tidal forcing of fluid bodies
that are slowly and uniformly rotating, are neutrally stratified and may
contain a solid or fluid core. This problem may be regarded as a simplified
model of astrophysical tides in convective regions of stars and giant planets.
The response can be separated into non-wavelike and wavelike parts, where the
former is related instantaneously to the tidal potential and the latter may
involve resonances or other singularities. The imaginary part of the potential
Love number of the body, which is directly related to the rates of energy and
angular momentum exchange in the tidal interaction and to the rate of
dissipation of energy, may have a complicated dependence on the tidal
frequency. However, a certain frequency-average of this quantity is independent
of the dissipative properties of the fluid and can be determined by means of an
impulse calculation. The result is a strongly increasing function of the size
of the core when the tidal potential is a sectoral harmonic, especially when
the body is not strongly centrally condensed. However, the same is not true for
tesseral harmonics, which receive a richer response and may therefore be
important in determining tidal evolution even though they are usually
subdominant in the expansion of the tidal potential. We also discuss
analytically the low-frequency response of a slowly rotating homogeneous fluid
body to tidal potentials proportional to spherical harmonics of degrees less
than five. Tesseral harmonics of degrees greater than two, such as are present
in the case of a spin-orbit misalignment, can resonate with inertial modes of
the full sphere, leading to an enhanced tidal interaction.",1211.0837v1
2015-04-24,Signatures of indirect K-edge resonant inelastic x-ray scattering on magnetic excitations in triangular lattice antiferromagnet,"We compute the K-edge indirect resonant inelastic x-ray scattering (RIXS)
spectrum of a triangular lattice antiferromagnet in its ordered coplanar 3-
sublattice 120 degree magnetic state. By considering the first order
self$-$energy corrections to the spin wave spectrum, magnon decay rate,
bimagnon interactions within the ladder approximation Bethe-Salpeter scheme,
and the effect of three-magnon contributions up to 1/S- order we find that the
RIXS spectra is non-trivially affected. For a purely isotropic triangular
lattice model, the peak splitting mechanism and the appearance of a multipeak
RIXS structure is primarily dictated by the damping of magnon modes. At a
scattering wavevector corresponding to the zone center \Gamma point and at the
roton point q=M, where the magnon decay rate is zero, a stable single peak
forms. At the $\Gamma$ point, the contribution is purely trimagnon at the 1/S
level and occurs approximately at the trimagnon energy of 6JS. The roton peak
occurs at a lower energy of 4JS. The K-edge single peak RIXS spectra at the
roton momentum can be utilized as an experimental signature to detect the
presence of roton excitations. A unique feature of the triangular lattice
K-edge RIXS spectra is the nonvanishing RIXS intensity at both the zone center
$\Gamma$ point and the antiferromagnetic wavevector K point. This result is in
sharp contrast to the vanishing K-edge RIXS intensity of the collinear magnetic
phases on the square lattice. We find that including XXZ anisotropy leads to
additional peak splitting, including at the roton scattering wavevector where
the single peak destabilizes towards a two-peak structure. The observed
splitting is consistent with our earlier theoretical prediction of the effects
of spatial anisotropy on the RIXS spectra of a frustrated quantum magnet [Luo,
Datta, and Yao, Phys. Rev. B 89, 165103 (2014)].",1504.06609v1
2022-02-28,Differential cross sections and photon beam asymmetries of $η$ photoproduction on the proton at $E_γ$ = 1.3-2.4 GeV,"We have carried out exclusive measurements for the photoproduction of an
$\eta$ meson from a proton target with an egg-shaped calorimeter made of BGO
crystals (BGOegg) and forward charged-particle detectors at the SPring-8 LEPS2
beamline. The differential cross sections and photon beam asymmetries of the
$\gamma p \to \eta p$ reaction are measured in a center-of-mass energy ($W$)
range of $1.82$-$2.32$ GeV and a polar angle range of $-1.0 <
\cos{\theta^{\eta}_{\mathrm{c.m.}}} < 0.6$. The reaction is identified by
selecting a proton and two $\gamma$'s produced by an $\eta$-meson decay. The
kinematic fit method was employed to select the reaction candidate with the
confidence level larger than $1$\%. A bump structure at $W$ = $2.0$-$2.3$ GeV
in the differential cross section is confirmed at extremely backward $\eta$
polar angles, where the existing data are inconsistent with each other. This
bump structure is likely associated with high-spin resonances that couple with
$s\bar{s}$ quarks. The results of the photon beam asymmetries in a wide $\eta$
polar angle range are new for the photon beam energies exceeding $2.1$ GeV.
These results are not reproduced by the existing partial wave analyses. They
provide an additional constraint to nucleon resonance studies at high energies.",2202.13688v1
2014-04-18,"Hydrodynamic and kinetic models for spin-1/2 electron-positron quantum plasmas: Annihilation interaction, helicity conservation, and wave dispersion in magnetized plasmas","We discuss complete theory of spin-1/2 electron-positron quantum plasmas,
when electrons and positrons move with velocities mach smaller than the speed
of light. We derive a set of two fluid quantum hydrodynamic equations
consisting of the continuity, Euler, spin (magnetic moment) evolution equations
for each species. We explicitly include the Coulomb, spin-spin, Darwin and
annihilation interactions. The annihilation interaction is the main topic of
the paper. We consider contribution of the annihilation interaction in the
quantum hydrodynamic equations and in spectrum of waves in magnetized
electron-positron plasmas. We consider propagation of waves parallel and
perpendicular to an external magnetic field. We also consider oblique
propagation of longitudinal waves. We derive set of quantum kinetic equations
for electron-positron plasmas with the Darwin and annihilation interactions. We
apply the kinetic theory for the linear wave behavior in absence of external
fields. We calculate contribution of the Darwin and annihilation interactions
in the Landau damping of the Langmuir waves. We should mention that the
annihilation interaction does not change number of particles in the system. It
does not related to annihilation itself, but it exists as a result of
interaction of an electron-positron pair via conversion of the pair into
virtual photon. A pair of the non-linear Schrodinger equations for
electron-positron plasmas including the Darwin and annihilation interactions.
Existence of conserving helicity in electron-positron quantum plasmas of
spinning particles with the Darwin and annihilation interactions is
demonstrated. We show that annihilation interaction plays an important role in
quantum electron-positron plasmas giving contribution of the same magnitude as
the spin-spin interaction.",1404.4899v1
2014-11-19,Variational Monte Carlo Method in the Presence of Spin-Orbit Interaction and Its Application to the Kitaev and Kitaev-Heisenberg Model,"We propose an accurate variational Monte Carlo method applicable in the
presence of the strong spin-orbit interaction. Our variational wave functions
consist of generalized Pfaffian-Slater wave functions that involve mixtures of
singlet and triplet Cooper pairs, Jastrow-Gutzwiller-type pro- jections, and
quantum number projections. The generalized wave functions allow any symmetry
breaking states, ranging from magnetic and/or charge ordered states to
superconducting states and their fluctuations, on equal footing without any ad
hoc ansatz for variational wave functions. We de- tail our optimization scheme
for the generalized Pfaffian-Slater wave functions with complex-number
variational parameters. Generalized quantum number projections are also
introduced, which im- poses the conservation of not only spin and momentum
quantum numbers but also Wilson loops. As a demonstration of the capability of
the present variational Monte Carlo method, the accuracy and efficiency of the
present method is tested for the Kitaev and Kitaev-Heisenberg models. The
Kitaev model serves as a critical benchmark of the present method: The exact
ground state of the model is a typical gapless quantum spin liquid far beyond
the applicability range of simple mean-field wave functions. The newly
introduced quantum number projections precisely reproduce the ground state
degeneracy of the Kitaev spin liquids, in addition to their ground state
energy. Our framework offers accurate solutions for the systems where strong
electron correlation and spin-orbit interaction coexist.",1411.5198v2
2018-06-21,"Flat Bands, Indirect Gaps, and Unconventional Spin-Wave Behavior Induced by a Periodic Dzyaloshinskii-Moriya Interaction","Periodically patterned metamaterials are known for exhibiting wave properties
similar to the ones observed in electronic band structures in crystal lattices.
In particular, periodic ferromagnetic materials are characterized by the
presence of bands and bandgaps in their spin-wave spectrum at tunable GHz
frequencies. Recently, the fabrication of magnets hosting Dzyaloshinskii-Moriya
interactions has been pursued with high interest since properties such as the
stabilization of chiral spin textures and nonreciprocal spin-wave propagation
emerge from this antisymmetric exchange coupling. In this context, to further
engineer the magnon band structure, we propose the implementation of magnonic
crystals with periodic Dzyaloshinskii-Moriya interactions, which can be
obtained, for instance, via patterning of periodic arrays of heavy-metals wires
on top of an ultrathin magnetic film. We demonstrate through theoretical
calculations and micromagnetic simulations that such systems show an unusual
evolution of the standing spin waves around the gaps in areas of the film that
are in contact with the heavy-metal wires. We also predict the emergence of
indirect gaps and flat bands and, effects that depend on the strength of the
Dzyaloshinskii-Moriya interaction. This study opens new routes towards
engineered metamaterials for spin-wave-based devices.",1806.08333v2
2014-06-23,Role of electron-phonon interaction in a magnetically driven mechanism for superconductivity,"We use the renormalization group method to examine the effect of phonon
mediated interaction on d-wave superconductivity, as driven by spin
fluctuations in a quasi-one-dimensional electron system. The influence of a
tight-binding electron-phonon interaction on the spin-density-wave and d-wave
superconducting instability lines is calculated for arbitrary temperature,
phonon frequency and antinesting of the Fermi surface.The domain of
electron-phonon coupling strength where spin-density-wave order becomes
unstable against the formation of a bond-order-wave or Peierls state is
determined at weak antinesting. We show the existence of a positive isotope
effect for spin-density-wave and d-wave superconducting critical temperatures
which scales with the antinesting distance from quantum critical point where
the two instabilities merge. We single out a low phonon frequency zone where
the bond-oder-wave ordering gives rise to triplet f-wave superconductivity
under nesting alteration, with both orderings displaying a negative isotope
effect. We also study the electron-phonon strengthening of spin fluctuations at
the origin of extended quantum criticality in the metallic phase above
superconductivity. The impact of our results on quasi-one-dimensional organic
conductors like the Bechgaard salts where a Peierls distortion is absent and
superconductivity emerges near a spin-density-wave state under pressure is
emphasized.",1406.6086v2
2023-06-28,Suppression of the spin waves nonreciprocity due to interfacial Dzyaloshinskii Moriya interaction by lateral confinement in magnetic nanostructures,"Despite the huge recent interest towards chiral magnetism related to the
interfacial Dzyaloshinskii Moriya interaction (iDMI) in layered systems, there
is a lack of experimental data on the effect of iDMI on the spin waves
eigenmodes of laterally confined nanostructures. Here we exploit Brillouin
Light Scattering (BLS) to analyze the spin wave eigenmodes of non-interacting
circular and elliptical dots, as well as of long stripes, patterned starting
from a Pt(3.4 nm)/CoFeB(0.8 nm) bilayer, with lateral dimensions ranging from
100 nm to 400 nm. Our experimental results, corroborated by micromagnetic
simulations based on the GPU-accelerated MuMax3 software package, provide
evidence for a strong suppression of the frequency asymmetry between
counter-propagating spin waves (corresponding to either Stokes or anti-Stokes
peaks in BLS spectra), when the lateral confinement is reduced from 400 nm to
100 nm, i.e. when it becomes lower than the light wavelength. Such an evolution
reflects the modification of the spin wave character from propagating to
stationary and indicates that the BLS based method of quantifying the i-DMI
strength from the frequency difference of counter propagating spin waves is not
applicable in the case of magnetic elements with lateral dimension below about
400 nm.",2306.16310v1
2024-03-20,All-magnonic repeater based on bistability,"Bistability, a universal phenomenon found in diverse fields such as biology,
chemistry, and physics, describes a scenario in which a system has two stable
equilibrium states and resets to one of the two states. The ability to switch
between these two states is the basis for a wide range of applications,
particularly in memory and logic operations. Here, we present a universal
approach to achieve bistable switching in magnonics, the field processing data
using spin waves. As an exemplary application, we use magnonic bistability to
experimentally demonstrate the still missing magnonic repeater. A pronounced
bistable window is observed in a 1um wide magnonic conduit under an external rf
drive characterized by two magnonic stable states defined as low and high
spin-wave amplitudes. The switching between these two states is realized by
another propagating spin wave sent into the rf driven region. This magnonic
bistable switching is used to design the magnonic repeater, which receives the
original decayed and distorted spin wave and regenerates a new spin wave with
amplified amplitude and normalized phase. Our magnonic repeater is proposed to
be installed at the inputs of each magnonic logic gate to overcome the
spin-wave amplitude degradation and phase distortion during previous
propagation and achieve integrated magnonic circuits or magnonic neuromorphic
networks.",2403.13276v1
2011-08-15,Search for Narrow Nucleon Resonance in $γp\to ηp$,"Results of a partial wave analysis of new high-statistics data on $\gamma
p\to p\eta$ from MAMI are presented. A fit using known broad resonances and
only standard background amplitudes can not describe the relatively narrow
peaking structure in the cross section in the mass region of 1660-1750 MeV
which follows a minimum. An improved description of the data can be reached by
either assuming the existence of a narrow resonance at a mass of about 1700 MeV
with small photo-coupling or by a threshold effect. In the latter case the
observed structure is explained by a strong (resonant or non-resonant) $\gamma
p\to\omega p$ coupling in the $S_{11}$ partial wave. When the beam asymmetry
data, published by part of the GRAAL collaboration, are included in the fit,
the solution with a narrow $P_{11}$ state is slightly preferred. In that fit,
mass and width of the hypothetical resonance are determined to $M\sim$1694 MeV
and $\Gamma\sim 40$ MeV, respectively, and the photo-coupling to $\sqrt{{\rm
Br}_{\eta N}} A_{1/2}^p \sim 2.6\cdot 10^{-3}$ GeV$^{-1/2}$. High precision
measurements of the target asymmetry and $F$-observable are mandatory to
establish the possible existence of such a narrow state and to provide the
necessary information to define which partial wave is responsible for the
structure observed in the data.",1108.3010v2
2013-04-13,Universality in s-wave and higher partial wave Feshbach resonances: an illustration with a single atom near two scattering centers,"It is well-known that cold atoms near s-wave Feshbach resonances have
universal properties that are insensitive to the short-range details of the
interaction. What is less known is that atoms near higher partial wave Feshbach
resonances also have remarkable universal properties. We illustrate this with a
single atom interacting resonantly with two fixed static centers. At a Feshbach
resonance point with orbital angular momentum $L\ge1$, we find $2L+1$ shallow
bound states whose energies behave like $1/R^{2L+1}$ when the distance $R$
between the two centers is large. We then compute corrections to the binding
energies due to other parameters in the effective range expansions. For
completeness we also compute the binding energies near s-wave Feshbach
resonances, taking into account the corrections. Afterwards we turn to the
bound states at large but finite scattering volumes. For p-wave and higher
partial wave resonances, we derive a simple formula for the energies in terms
of a parameter called ""proximity parameter"". These results are applicable to a
free atom interacting resonantly with two atoms that are localized to two
lattice sites of an optical lattice, and to one light atom interacting with two
heavy ones in free space. Modifications of the low energy physics due to the
long range Van der Waals potential are also discussed.",1304.3791v2
2015-03-24,A mathematical study of meteo and landslide tsunamis : The Proudman resonance,"In this paper, we want to understand the Proudman resonance. It is a resonant
respond in shallow waters of a water body on a traveling atmospheric
disturbance when the speed of the disturbance is close to the typical water
wave velocity. We show here that the same kind of resonance exists for
landslide tsunamis and we propose a mathematical approach to investigate these
phenomena based on the derivation, justification and analysis of relevant
asymptotic models. This approach allows us to investigate more complex
phenomena that are not dealt with in the physics literature such as the
influence of a variable bottom or the generalization of the Proudman resonance
in deeper waters. First, we prove a local well-posedness of the water waves
equations with a moving bottom and a non constant pressure at the surface
taking into account the dependence of small physical parameters and we show
that these equations are a Hamiltonian system (which extend the result of
Zakharov [33]). Then, we justify some linear asymptotic models in order to
study the Proudman resonance and submarine landslide tsunamis; we study the
linear water waves equations and dispersion estimates allow us to investigate
the amplitude of the sea level. To complete these asymptotic models, we add
some numerical simulations.",1503.07028v2
2016-02-22,Microwave dynamics of high aspect ratio superconducting nanowires studied using self-resonance,"We study the microwave impedance of extremely high aspect ratio (length/width
~ 5,000) superconducting niobium nitride nanowires. The nanowires are
fabricated in a compact meander geometry that is in series with the center
conductor of a 50 ohm coplanar waveguide transmission line. The transmission
coefficient of the sample is measured up to 20 GHz. At high frequency, a peak
in the transmission coefficient is seen. Numerical simulations show that this
is a half-wave resonance along the length of the nanowire, where the nanowire
acts as a high impedance, slow wave transmission line. This resonance sets the
upper frequency limit for these nanowires as inductive elements. Fitting
simulations to the measured resonance enables a precise determination of the
nanowire's complex sheet impedance at the resonance frequency. The real part is
a measure of dissipation, while the imaginary part is dominated by kinetic
inductance. We characterize the dependence of the sheet resistance and sheet
inductance on both temperature and current and compare the results to recent
theoretical predictions for disordered superconductors. These results can aid
in the understanding of high frequency devices based on superconducting
nanowires. They may also lead to the development of novel superconducting
devices such as ultra-compact resonators and slow-wave structures.",1602.06895v3
2017-11-27,Recent Results on Light-Meson Spectroscopy from COMPASS,"The main goal of the spectroscopy program at COMPASS is to explore the
light-meson spectrum below about $2\,\text{GeV}/c^2$ in diffractive production.
Our flagship channel is the decay into three charged pions: $p + \pi^-\to
\pi^-\pi^-\pi^+ + p_\text{recoil}$, for which COMPASS has acquired the so far
world's largest dataset of roughly $50\,\text{M}$ exclusive events using an
$190\,\text{GeV}/c$ $\pi^-$ beam. Based on this dataset, we performed an
extensive partial-wave analysis. In order to extract the resonance parameters
of the $\pi_J$ and $a_J$ states that appear in the $\pi^-\pi^-\pi^+$ system, we
performed the so far largest resonance-model fit, using Breit-Wigner resonances
and non-resonant contributions.
  This method in combination with the high statistical precision of our
measurement allows us to study ground and excited states. We have found an
evidence of the $a_1(1640)$ and $a_2(1700)$ in our data, which are the first
excitations of the $a_1(1260)$ and $a_2(1320)$, respectively. The relative
strength of the excited states with respect to the corresponding ground state
is larger in the $f_2(1270)\,\pi$ decay mode compared to the $\rho(770)\,\pi$
decay mode. We also study the spectrum of $\pi_2$ states in our data.
Therefore, we simultaneously describe four $J^{PC}=2^{-+}$ waves in the
resonance-model fit by using three $\pi_2$ resonances, the $\pi_2(1670)$, the
$\pi_2(1880)$, and the $\pi_2(2005)$. Within the limits of our model, we can
conclude that the $\pi_2(2005)$ is required to describe all four $2^{-+}$ waves
properly.",1711.09782v2
2019-07-23,Resonant high-energy bremsstrahlung of ultrarelativistic electrons in the field of a nucleus and an electromagnetic wave,"The actual theoretical research investigates the resonant spontaneous
bremsstrahlung (RSB) of ultrarelativistic electrons under the condition of
scattering on a nucleus in the field of a weak electromagnetic wave. The
progression of the functional mechanism indicates the transformation of the
intermediate virtual electron into the real particle state. As a result, the
initial second order process with accordance to the fine structure constant in
the light field productively splits into two consequent first order formations:
the laser-stimulated Compton effect and the laser-assisted scattering of an
electron on a nucleus. It is important to emphasize that the resonance
escalation possesses a possibility to develop within two reaction channels.
Therefore, the first channel - delineates the occurrence that correlates to the
spontaneous photon emission by an electron with subsequent scattering on a
nucleus. The second channel - illustrates the configuration corresponding to
the electron scattering on a nucleus with consecutive spontaneous photon
emission in the wave field. Moreover, the spontaneous photon radiation angle
allocates a single-valued dependency with the resonant frequency for the first
channel in contrast to the second displacement that categorizes a composite
area with three various resonant frequency magnitudes for the particular
emission angle diapason. The project data analysis proposes that the reaction
channels do not interfere within the whole range of observation. To summarize,
the investigation calculates that the particular cross-section within the
resonant ambience significantly exceeds the according cross-section in the
approximation of an external field absence. In conclusion, numerous scientific
facilities with specialization in pulsed laser radiation (SLAC, FAIR, XFEL,
ELI, XCELS) may experimentally validate the computational estimations.",1907.10431v1
2023-02-06,Heterogeneous integration of superconducting thin films and epitaxial semiconductor heterostructures with Lithium Niobate,"We report on scalable heterointegration of superconducting electrodes and
epitaxial semiconductor quantum dots on strong piezoelectric and optically
nonlinear lithium niobate. The implemented processes combine the
sputter-deposited thin film superconductor niobium nitride and III-V compound
semiconductor membranes onto the host substrate. The superconducting thin film
is employed as a zero-resistivity electrode material for a surface acoustic
wave resonator with internal quality factors $Q \approx 17000$ representing a
three-fold enhancement compared to identical devices with normal conducting
electrodes. Superconducting operation of $\approx 400\,\mathrm{MHz}$ resonators
is achieved to temperatures $T>7\,\mathrm{K}$ and electrical radio frequency
powers $P_{\mathrm{rf}}>+9\,\mathrm{dBm}$. Heterogeneously integrated single
quantum dots couple to the resonant phononic field of the surface acoustic wave
resonator operated in the superconducting regime. Position and frequency
selective coupling mediated by deformation potential coupling is validated
using time-integrated and time-resolved optical spectroscopy. Furthermore,
acoustoelectric charge state control is achieved in a modified device geometry
harnessing large piezoelectric fields inside the resonator. The hybrid quantum
dot - surface acoustic wave resonator can be scaled to higher operation
frequencies and smaller mode volumes for quantum phase modulation and
transduction between photons and phonons via the quantum dot. Finally, the
employed materials allow for the realization of other types of optoelectronic
devices, including superconducting single photon detectors and integrated
photonic and phononic circuits.",2302.02712v2
1998-12-08,MHD waves as a source of matter density fluctuations within solar interior,"It is shown that in the presence of a background magnetic field within solar
interior a cavity for low frequency MHD eigen modes (with periods 1-10 days)
near equatorial plane can arise. The lower boundary of the cavity coincides
with the centre of the Sun while the upper one corresponds to the Alfven
resonant layer where high accumulation of wave energy takes place. The
localization and the width of the Alfven resonance layer are determined by: (i)
the node number of eigen modes n = 1, 2,..., (ii) by the angle of oblique
propagation of waves with respect to the magnetic field, and (iii) by a low
magnitude of the background magnetic field itself, B=1-100 G. The amplitude of
eigen oscillations in a resonant layer determines the density fluctuation value
that is restricted through the imaginary part of eigen frequences. For large
node numbers n>>1 there appear many narrow resonant layers where a neutrino
propagates through a large density fluctuation \delta\rho/\rho with the
oscillation length that is much bigger than the width of a resonant layer. It
is shown that neutrino crosses many such bumps on the exponential background
profile that motivates to consider these MHD waves as a plausible matter noise
for the MSW solution to the Solar Neutrino Problem (SNP).",9812149v2
2006-03-17,Turbulence and particle acceleration in collisionless supernovae remnant shocks: I-Anisotropic spectra solutions,"This paper investigates the nature of the MHD turbulence excited by the
streaming of accelerated cosmic rays in a shock wave precursor. The two
recognised regimes (non-resonant and resonant) of the streaming instability are
taken into account. We show that the non-resonant instability is very efficient
and saturates through a balance between its growth and non-linear transfer. The
cosmic-ray resonant instability then takes over and is quenched by advection
through the shock. The level of turbulence is determined by the non-resonant
regime if the shock velocity $V_{\rm sh}$ is larger than a few times $\xi_{\rm
CR} c$, where $\xi_{\rm CR}$ is the ratio of the cosmic-ray pressure to the
shock kinetic energy. The instability determines the dependence of the spectrum
with respect to $k_\parallel$ (wavenumbers along the shock normal). The
transverse cascade of Alfv\'en waves simultaneously determines the dependence
in $k_{\perp}$. We also study the redistribution of turbulent energy between
forward and backward waves, which occurs through the interaction of two
Alfv\'en and one slow magneto-sonic wave. Eventually the spectra at the longest
wavelengths are found almost proportional to $k_{\parallel}^{-1}$. Downstream,
anisotropy is further enhanced through the compression at shock crossing.",0603461v1
2000-08-04,Stability of the Ground State of a Harmonic Oscillator in a Monochromatic Wave,"Classical and quantum dynamics of a harmonic oscillator in a monochromatic
wave is studied in the exact resonance and near resonance cases. This model
describes, in particular, a dynamics of a cold ion trapped in a linear ion trap
and interacting with two lasers fields with close frequencies. Analytically and
numerically a stability of the ``classical ground state'' (CGS) -- the vicinity
of the point ($x=0, p=0$) -- is analyzed. In the quantum case, the method for
studying a stability of the quantum ground state (QGS) is suggested, based on
the quasienergy representation. The dynamics depends on four parameters: the
detuning from the resonance, $\delta=\ell-\Omega/\omega$, where $\Omega$ and
$\omega$ are, respectively, the wave and the oscillator's frequencies; the
positive integer (resonance) number, $\ell$; the dimensionless Planck constant,
$h$, and the dimensionless wave amplitude, $\epsilon$. For $\delta=0$, the CGS
and the QGS are unstable for resonance numbers $\ell=1, 2$. For small
$\epsilon$, the QGS becomes more stable with increasing $\delta$ and decreasing
$h$. When $\epsilon$ increases, the influence of chaos on the stability of the
QGS is analyzed for different parameters of the model, $\ell$, $\delta$ and
$h$.",0008005v2
2008-11-28,The Effect of Random Surface Inhomogeneities on Microresonator Spectral Properties: Theory and Modeling at Millimeter Wave Range,"The influence of random surface inhomogeneities on spectral properties of
open microresonators is studied both theoretically and experimentally. To solve
the equations governing the dynamics of electromagnetic fields the method of
eigen-mode separation is applied previously developed with reference to
inhomogeneous systems subject to arbitrary external static potential. We prove
theoretically that it is the gradient mechanism of wave-surface scattering
which is the highly responsible for non-dissipative loss in the resonator. The
influence of side-boundary inhomogeneities on the resonator spectrum is shown
to be described in terms of effective renormalization of mode wave numbers
jointly with azimuth indices in the characteristic equation. To study
experimentally the effect of inhomogeneities on the resonator spectrum, the
method of modeling in the millimeter wave range is applied. As a model object
we use dielectric disc resonator (DDR) fitted with external inhomogeneities
randomly arranged at its side boundary. Experimental results show good
agreement with theoretical predictions as regards the predominance of the
gradient scattering mechanism. It is shown theoretically and confirmed in the
experiment that TM oscillations in the DDR are less affected by surface
inhomogeneities than TE oscillations with the same azimuth indices. The DDR
model chosen for our study as well as characteristic equations obtained
thereupon enable one to calculate both the eigen-frequencies and the Q-factors
of resonance spectral lines to fairly good accuracy. The results of
calculations agree well with obtained experimental data.",0811.4734v1
2012-10-03,Revisiting 1-Dimensional Double-Barrier Tunneling in Quantum Mechanics,"This paper revisited quantum tunneling dynamics through a square
double-barrier potential. We emphasized the similarity of tunneling dynamics
through double-barrier and that of optical Fabry--P$\acute{e}$rot (FP)
interferometer. Based on this similarity, we showed that the well-known
resonant tunneling can also be interpreted as a result of matter multi-wave
interference, analogous to that of FP interferometer. From this analogy, we
also got an analytical finesse formula of double-barrier. Compared with that
obtained numerically for a specific barrier configuration, we found that this
formula works well for resonances at ""deep tunneling region"". Besides that, we
also calculated standing wave spectrum inside the well of double barriers and
phase time of double-barrier tunneling. The wave number spectrums of standing
wave and phase time show another points of view on resonance. From
semi-numerical calculations, we interpreted the peak of phase time at resonance
as resonance life time, which coincides at least in order of magnitude with
that obtained from uncertainty principle. Not to our surprise, phase time of
double-barrier tunneling also saturates at long barrier length limit
$l\rightarrow\infty$ as that of tunneling through a single barrier, and the
limits are the same.",1210.0970v2
2014-11-01,Extraordinary focusing of sound above a soda can array without time reversal,"Recently, Lemoult et al. [Phys. Rev. Lett. 107, 064301 (2011)] used time
reversal to focus sound above an array of soda cans into a spot much smaller
than the acoustic wavelength in air. In this study, we show that equally sharp
focusing can be achieved without time reversal, by arranging transducers around
a nearly circular array of soda cans. The size of the focal spot at the center
of the array is made progressively smaller as the frequency approaches the
Helmholtz resonance frequency of a can from below, and, near the resonance,
becomes smaller than the size of a single can. We show that the locally
resonant metamaterial formed by soda cans supports a guided wave at frequencies
below the Helmholtz resonance frequency. The small focal spot results from a
small wavelength of this guided wave near the resonance in combination with a
near field effect making the acoustic field concentrate at the opening of a
can. The focusing is achieved with propagating rather than evanescent waves. No
sub-diffraction-limited focusing is observed if the diffraction limit is
defined with respect to the wavelength of the guided mode in the metamaterial
medium rather than the wavelength of the bulk wave in air.",1411.1016v2
2017-12-27,Resonant parametric interference effect in spontaneous bremsstrahlung of an electron in the field of a nucleus and two pulsed laser waves,"Resonant spontaneous bremsstrahlung of an electron scattered by a nucleus in
the field of two moderately strong pulsed laser waves is studied theoretically.
The process is studied in detail within the interference kinematic region. This
region is determined by scattering of particles in the same plane at
predetermined angles, at that stimulated absorption and emission of photons of
external pulsed waves by an electron occurs in correlated manner. The
correspondence between the emission angle and the final-electron energy is
established in the kinematic region where the resonant parametric interference
effect is manifested. The resonant differential cross section of ENSB process
with simultaneous registration of both emission angles of the spontaneous
photon and the scattered electron, can exceed by 4-5 orders of magnitude the
corresponding cross section in the absence of an external field. It was shown
for nonrelativistic electrons that the resonant cross section of ENSB in the
field of two pulsed laser waves within the interference region in two order of
magnitude may exceed corresponding cross section in the Bunkin-Fedorov
kinematic region. The obtained results may be experimentally verified, for
example, by scientific facilities at sources of pulsed laser radiation (SLAC,
FAIR, XFEL, ELI).",1712.09525v1
2018-05-24,Effective medium description of the resonant elastic-wave response at the periodically-uneven boundary of a half-space,"A periodically-uneven (in one horizontal direction) stress-free boundary
covering a linear, isotropic, homogeneous, lossless solid half space is
submitted to a vertically-propagating shear-horizontal plane, body wave. The
rigorous theory of this elastodynamic scattering problem is given and the means
by which it can be numerically solved are outlined. At quasi-static
frequencies, the solution is obtained from one linear equation in one unknown.
At higher, although still low, frequencies, a suitable approximation of the
solution is obtained from a system of two linear equations in two unknowns.
This solution is shown to be equivalent to that of the problem of a
vertically-propagating shear-horizontal plane body wave traveling in the same
solid medium as before, but with a linear, homogeneous, isotropic layer
replacing the previous uneven boundary. The thickness of this layer is equal to
the vertical distance between the extrema of the boundary uneveness and the
effective body wave velocity therein is equal to that of the underlying solid,
but the effective shear modulus of the layer, whose expression is given in
explicit algebraic form, is different from that of the underlying solid,
notably by the fact that it is dispersive and lossy. It is shown that this
dispersive, lossy effective layer, overriding the nondispersive, lossless solid
half space, gives rise to two distinctive features of low-frequency response: a
Love mode resonance and a Fixed-base shear wall pseudo-resonance. This model of
effective layer with dispersive, lossy properties, enables simple explanations
of how the low-frequency resonance and pseudo-resonance vary with the geometric
parameters (and over a wide range of the latter) of the uneven boundary.",1805.09823v1
2018-10-26,Birkhoff normal form and long time existence for periodic gravity water waves,"We consider the gravity water waves system with a periodic one-dimensional
interface in infinite depth, and prove a rigorous reduction of these equations
to Birkhoff normal form up to degree four. This proves a conjecture of
Zakharov-Dyachenko [55] suggested by the formal Birkhoff integrability of the
water waves Hamiltonian truncated at order four. As a consequence, we also
obtain a long-time stability result: periodic perturbations of a flat interface
that are of size $\varepsilon$ in a sufficiently smooth Sobolev space lead to
solutions that remain regular and small up to times of order
$\varepsilon^{-3}$. This time scale is expected to be optimal. Main
difficulties in the proof are the presence of non-trivial resonant four-waves
interactions, the so-called Benjamin-Feir resonances, the small divisors
arising from near-resonances and the quasilinear nature of the equations. Some
of the main ingredients that we use are: (1) a reduction procedure to constant
coefficient operators up to smoothing remainders, that, together with the
verification of key algebraic cancellations of the system, implies the
integrability of the equations at non-negative orders; (2) a
Poincar\'e-Birkhoff normal form of the smoothing remainders that deals with
near-resonances; (3) an a priori algebraic identification argument of the above
Poincar\'e- Birkhoff normal form equations with the formal Hamiltonian
computations of [55, 19, 27, 17], that allows us to handle the Benjamin-Feir
resonances.",1810.11549v2
2014-06-25,"Surface acoustic wave driven ferromagnetic resonance in (Ga,Mn)(As,P) epilayers","Interdigitated transducers were used to generate and detect surface acoustic
waves on a thin layer of (Ga,Mn)(As,P). The out-of-plane uniaxial magnetic
anisotropy of this dilute magnetic semiconductor is very sensitive to the
strain of the layer, making it an ideal test material for the dynamic control
of magnetization via magneto-striction. The time-domain measurement of the
amplitude and phase of the transmitted SAW during magnetic field sweeps
indicated a clear resonant behavior at a field close to the one calculated to
give a precession frequency equal to the SAW frequency. A resonance was
observed from 5K to 85K, just below the Curie temperature of the layer. A full
analytical treatment of the coupled magnetization/acoustic dynamics showed that
the magneto-strictive coupling modifies the elastic constants of the material
and accordingly the wave-vector solution to the elastic wave equation. The
shape and position of the resonance were well reproduced by the calculations,
in particular the fact that velocity (phase) variations resonated at lower
fields than the acoustic attenuation variations.",1406.6483v1
2020-09-23,Quantum frequency conversion based on resonant four-wave mixing,"Quantum frequency conversion (QFC), a critical technology in photonic quantum
information science, requires that the quantum characteristics of the
frequency-converted photon must be the same as the input photon except for the
color. In nonlinear optics, the wave mixing effect far away from the resonance
condition is often used to realize QFC because it can prevent the vacuum field
reservoir from destroying the quantum state of the converted photon
effectively. Under conditions far away from resonance, experiments typically
require strong pump light to generate large nonlinear interactions to achieve
high-efficiency QFC. However, strong pump light often generates additional
noise photons through spontaneous Raman or parametric conversion processes.
Herein, we theoretically study another efficient QFC scheme based on a resonant
four-wave mixing system. Due to the effect of electromagnetically induced
transparency (EIT), this resonant QFC scheme can greatly suppress vacuum field
noise at low light levels; consequently, the converted photon can inherit the
quantum state of the input photon with high fidelity. Our research demonstrates
that if the conversion efficiency of the EIT-based QFC is close to 100%, the
wave function and quadrature variance of the converted photon are almost the
same as the input probe photon.",2009.11021v2
2021-04-05,Two-body wave functions and compositeness from scattering amplitudes: II. Application to the physical $N ^{\ast}$ and $Δ^{\ast}$ resonances,"The meson-baryon molecular components for the $N^{\ast}$ and $\Delta ^{\ast}$
resonances are investigated in terms of the compositeness, which is defined as
the norm of the two-body wave function from the meson-baryon scattering
amplitudes. The scattering amplitudes are constructed in a $\pi N$-$\eta
N$-$\sigma N$-$\rho N$-$\pi \Delta$ coupled-channels problem in a meson
exchange model together with several bare $N^{\ast}$ and $\Delta ^{\ast}$
states, and parameters are fitted so as to reproduce the on-shell $\pi N$
partial wave amplitudes up to the center-of-mass energy 1.9 GeV with the
orbital angular momentum $L \le 2$. As a result, the Roper resonance $N (1440)$
is found to be dominated by the $\pi N$ and $\sigma N$ molecular components
while the bare-state contribution is small. The squared wave functions in
coordinate space imply that both in the $\pi N$ and $\sigma N$ channels the
separation between the meson and baryon is about more than 1 fm for the $N
(1440)$ resonance. On the other hand, dominant meson-baryon molecular
components are not observed in any other $N^{\ast}$ and $\Delta ^{\ast}$
resonances in the present model, although they have some fractions of the
meson-baryon clouds.",2104.01962v2
2022-07-28,Quasi-resonant diffusion of wave packets in one-dimensional disordered mosaic lattices,"We investigate numerically the time evolution of wave packets incident on
one-dimensional semi-infinite lattices with mosaic modulated random on-site
potentials, which are characterized by the integer-valued modulation period
$\kappa$ and the disorder strength $W$. For Gaussian wave packets with the
central energy $E_0$ and a small spectral width, we perform extensive numerical
calculations of the disorder-averaged time-dependent reflectance, $\langle
R(t)\rangle$, for various values of $E_0$, $\kappa$, and $W$. We find that the
long-time behavior of $\langle R(t)\rangle$ obeys a power law of the form
$t^{-\gamma}$ in all cases. In the presence of the mosaic modulation, $\gamma$
is equal to 2 for almost all values of $E_0$, implying the onset of the
Anderson localization, while at a finite number of discrete values of $E_0$
dependent on $\kappa$, $\gamma$ approaches 3/2, implying the onset of the
classical diffusion. This phenomenon is independent of the disorder strength
and arises in a quasi-resonant manner such that $\gamma$ varies rapidly from
3/2 to 2 in a narrow energy range as $E_0$ varies away from the quasi-resonance
values. We deduce a simple analytical formula for the quasi-resonance energies
and provide an explanation of the delocalization phenomenon based on the
interplay between randomness and band structure and the node structure of the
wave functions. We explore the nature of the states at the quasi-resonance
energies using a finite-size scaling analysis of the average participation
ratio and find that the states are neither extended nor exponentially
localized, but ciritical states..",2207.13906v2
2000-01-08,Gravitational Waves from Low-Mass X-ray Binaries: a Status Report,"We summarize the observations of the spin periods of rapidly accreting
neutron stars. If gravitational radiation is responsible for balancing the
accretion torque at the observed spin frequencies of ~300 Hz, then the
brightest of these systems make excellent gravitational wave sources for
LIGO-II and beyond. We review the recent theoretical progress on two mechanisms
for gravitational wave emission: mass quadrupole radiation from deformed
neutron star crusts and current quadrupole radiation from r-mode pulsations in
neutron star cores.",0001129v1
2000-07-19,Scattering of Dirac Waves off Kerr Black Holes,"Chandrasekhar separated the Dirac equation for spinning and massive particles
in Kerr geometry into radial and angular parts. Here we solve the complete wave
equation and find out how the Dirac wave scatters off Kerr black holes. The
eigenfunctions, eigenvalues and reflection and transmission co-efficients are
computed. We compare the solutions with several parameters to show how a
spinning black hole distinguishes mass and energy of incoming waves. Very close
to the horizon the solutions become independent of the particle parameters
indicating an universality of the behaviour.",0007277v1
2000-05-16,Coexistent States of Charge Density Wave and Spin Density Wave in One-Dimensional Systems with the Inter-site Coulomb Interaction under the Electron Filling Control,"The coexistent state of the spin density wave (SDW) and the charge density
wave (CDW) in the one-dimensional systems is studied by the mean field
approximation at T=0 in various electron-filling cases. We find that the
coexistent state of SDW and CDW is stabilized when the on-site and the
inter-site Coulomb interactions have the values estimated for the organic
conductors. The ground state energies have cusp-like minima at 1/4, 3/8, 5/12,
7/16, 7/20 and 9/20-fillings.",0005256v1
2003-10-31,Conversion of dislocation oscillation waves to spin ones in the vicinity of OPT temperatures,"Dislocation waves in magnetic crystals in the vicinity of orientation phase
transition (OPT) temperatures are considered in a frame of the field theory of
the defects. The singularities of the dislocation flows, elastic deformations
and magnetization occur if the magnetic subsystem is inhomogeneous and the
dispersion of the media is not taken into account. Media dispersion causes a
regularity of these parameters and a conversion of the spin wave to the
dislocation wave.",0310762v1
2003-11-12,Hartree-Fock energy of a density wave in a spin polarized two-dimensional electron gas,"We calculate the Hartree-Fock energy of a density-wave in a spin polarized
two-dimensional electron gas using a short-range repulsive interaction. We find
that the stable ground state for a short-range potential is always either the
paramagnetic state or the uniform ferromagnetic state. The energy of a
density-wave state is, however, reduced by a factor proportional to (1 -
zeta^2), where zeta is the polarization of the electron gas. Since this
situation occurs in the most unfavorable conditions (short-range repulsive
interaction) it is therefore conceivable that by including higher order
many-body corrections to the interaction a density-wave ground state is indeed
found to be stable.",0311292v1
2005-02-25,Triplet superconducting pairing and density-wave instabilities in organic conductors,"Using a renormalization group approach, we determine the phase diagram of an
extended quasi-one-dimensional electron gas model that includes interchain
hopping, nesting deviations and both intrachain and interchain repulsive
interactions. We find a close proximity of spin-density- and
charge-density-wave phases, singlet d-wave and triplet f-wave superconducting
phases. There is a striking correspondence between our results and recent
puzzling experimental findings in the Bechgaard salts, including the
coexistence of spin-density-wave and charge-density-wave phases and the
possibility of a triplet pairing in the superconducting phase.",0502614v2
2003-02-12,Detectability of Gravitational Waves from SN 1987A,"We discuss the potential for detection of gravitational waves from a rapidly
spinning neutron star produced by supernova 1987A taking the parameters claimed
by Middleditch et al. (2000) at face value. Asssuming that the dominant
mechanism for spin down is gravitational waves emitted by a freely precessing
neutron star, it is possible to constrain the wobble angle, the effective
moment of inertai of the precessing crust and the crust cracking stress limit.
Our analysis, suggests that, if the interpretation of the Middleditch data is
correct, the compact remnant of SN 1987A may well provide a reliable and
predictable source of gravitational waves well within the capability of LIGO
II.",0302050v1
1997-06-20,Time development of a wave packet and the time delay,"A one-dimensional scattering problem off a $\delta$-shaped potential is
solved analytically and the time development of a wave packet is derived from
the time-dependent Schr\""odinger equation. The exact and explicit expression of
the scattered wave packet supplies us with interesting information about the
""time delay"" by potential scattering in the asymptotic region. It is
demonstrated that a wave packet scattered by a spin-flipping potential can give
us quite a different value for the delay times from that obtained without
spin-degrees of freedom.",9706048v1
2009-08-29,Cavity-Mediated Strong Matter Wave Bistability in a Spin-1 Condensate,"We study matter wave bistability in a spin-1 Bose-Einstein condensate
dispersively coupled to a unidirectional ring cavity. A unique feature is that
the population exchange among different modes of matter fields are accomplished
via the spin-exchange collisions. We show that the interplay between the atomic
spin mixing and the cavity light field can lead to a strong matter wave
nonlinearity, making matter wave bistability in a cavity at the single-photon
level achievable.",0908.4333v1
2011-02-02,Skyrmion-antiSkyrmion pairs in Ultracold Atomic Gases,"We study theoretically the dynamics of two-component Bose-Einstein
condensates in two dimensions, which admit topological excitations related to
the Skyrmions of nuclear physics. We show that there exists a branch of
uniformly propagating solitary waves characterised by a conserved momentum.
These excitations exhibit a cross-over from spatially extended spin-wave states
at low momentum to a localised ""spin-wave droplet"" at intermediate momentum; at
still higher momentum, the configuration evolves continuously into a
Skyrmion-antiSkyrmion pair. We discuss how these solitary waves can be
generated and studied in experiment.",1102.0340v1
2014-05-15,Radiative corrections to the Coulomb law and model of dense quantum plasmas: Dispersion of waves in magnetized quantum plasmas,"Two kinds of the quantum electrodynamic radiative corrections to
electromagnetic interaction and their influence on properties of highly dense
quantum plasmas are considered. Linear radiative correction to the Coulomb
interaction are considered. Its contribution in the spectrum of the Langmuir
waves is presented. The second kind of the radiative corrections is related to
nonlinearity of the Maxwell equations for strong electromagnetic field. Its
contribution in spectrum of transverse waves of magnetized plasmas is briefly
discussed. At consideration of the Langmuir wave spectrum we included effect of
different distribution of the spin-up and spin-down electrons revealing in a
shift of the Fermi pressure.",1405.3914v1
2018-11-06,Parametrically squeezed states of microwave magnons in yttrium iron garnet films,"We demonstrate theoretically, and confirm experimentally, that nonlinear spin
waves excited in thin yttrium iron garnet films are good candidates for
squeezing vacuum quantum noise. The experimental demonstration is in the form
of a measurement of spin-wave induced modulation instability (IMI) conducted in
the classical regime. The experiment evidences strong phase locking of an idler
wave parametrically generated in the film with a deterministic small-signal
wave launched into the film from an external source. The theory predicts that
the same behaviour will be observed for vacuum quantum noise, resulting in
squeezing of the noise.",1811.02104v1
2018-07-17,A Luneburg lens for spin waves,"We report on the theory of a Luneburg lens for forward-volume magnetostatic
spin waves, and verify its operation via micromagnetic modelling. The lens
converts a plane wave to a point source (and vice versa) by a designed graded
index, realised here by either modulating the thickness or the saturation
magnetization in a circular region. We find that the lens enhances the wave
amplitude by 5 times at the lens focus, and 47% of the incident energy arrives
in the focus region. Furthermore, small deviations in the profile can still
result in good focusing, if the lens index is graded smoothly.",1807.06705v1
2019-02-18,The quantum theory and topological features of photon,"In this paper, we have proposed the spinor wave equation of free and non-free
photon. On this basis, we given the spin operators and spin wave functions of
photon, and calculated the wave function of photon in vacuum and medium. In
addition, we have given the quantum Berry phase and Chern number with the
photon wave function, which can be used to studied the quantum topological
features of photon in one-dimensional period medium.",1902.06596v1
2021-03-03,The studies on phonons and magnons in (Ni80Fe20/Au/Co/Au) multilayers of different number of repetitions,"In Ni80Fe20/Au/Co/Au deposited on silicon substrate the interaction between
spin waves and surface acoustic waves is observed by Brillion light scattering
spectroscopy. We show that by changing the number of receptions in the
multilayer we can tune the dispersion of surface acoustic waves (SAWs) not
affecting significantly fundamentals spin wave (SW) mode. As a result, we can
control (activate or deactivate) the magnetoelastic interaction between
fundamental SW mode and SAWs by the thickness of the magnetostrictive
multilayer.",2103.02686v2
2023-03-06,Leaky Wave Antenna by Spin Photonic Topological Insulators Using 30-degree rhombic unit cell,"A new spin photonic topological insulator model with a 30-degree rhombic unit
cell is presented and analyzed. Topological band gaps and the robustness
against the defects are shown. The edge modes are studied via full-wave
simulation of a ribbon of unit cells. By using the structure in the fast wave
region, a leaky wave antenna is proposed with a gain of 18.2dB.",2303.07117v2
1994-08-19,Spin dynamics of the doped t-J model,"We present a new method for studying the low energy excitations in finite
cluster systems and apply it to clarify the nature of the low energy spin
excitations in the moderately doped t-J model.
  We find that the character of the low energy spin excitations changes within
the Brillouin zone, with the dominant excitation for momentum transfer (pi,pi)
being a spin wave-like collective mode.
  Spin excitations with momentum transfer different from (pi,pi) have
particle-hole character. We give an explicit construction of a low energy
collective spin mode in a system with `almost broken symmetry' and demonstrate
its validity by explicit numerical check.",9408057v1
1995-05-26,A Spin Model for Investigating Chirality,"Spin chirality has generated great interest recently both from possible
applications to flux phases and intrinsically, as an example of a several-site
magnetic order parameter that can be long-ranged even where simpler order
parameters are not. Previous work (motivated by the flux phases) has focused on
antiferromagnetic chiral order; we construct a model in which the chirality
orders ferromagnetically and investigate the model's behavior as a function of
spin. Enlisting the aid of exact diagonalization, spin-waves, perturbation
theory, and mean fields, we conclude that the model likely has long-ranged
chiral order for spins 1 and greater and no non-trivial chiral order for spin
1/2.",9505143v1
1997-07-15,Alternating spin chains with singlet ground states,"We investigate low-energy properties of the alternating spin chain model
composed of spin $s_1$ and $s_2$ with a singlet ground state. After examining
the spin-wave spectrum in detail, we map low-energy spin excitations to the
O(3) non-linear sigma model in order to take into account quantum fluctuations.
Analyzing the topological term in the resulting sigma model, we discuss how the
massless or massive excitations are developed, especially according to the
topological nature of the alternating spin system.",9707148v1
1998-10-30,Two-Dimensional Quantum Spin Systems with Ladder and Plaquette Structure,"We investigate low-energy properties of two-dimensional quantum spin systems
with the ladder and plaquette structures, which are described by a generalized
antiferromagnetic Heisenberg model with both of the bond and spin alternations.
By exploiting a non-linear $\sigma$ model technique and a modified spin wave
approach, we evaluate the spin gap and the spontaneous magnetization to discuss
the quantum phase transition between the ordered and disordered states. We
argue how the spin-gapped phase is driven to the antiferromagnetic phase in the
phase diagram.",9810414v1
1999-05-19,Oscillation modes of two-dimensional nanostructures within the time-dependent local-spin-density approximation,"We apply the time-dependent local-spin-density approximation as general
theory to describe ground states and spin-density oscillations in the linear
response regime of two-dimensional nanostructures of arbitrary shape. For this
purpose, a frequency analysis of the simulated real-time evolution is
performed. The effect on the response of the recently proposed spin-density
waves in the ground state of certain parabolic quantum dots is considered. They
lead to the prediction of a new class of excitations, soft spin-twist modes,
with energies well below that of the spin dipole oscillation.",9905288v2
1999-07-23,Spin relaxation in semiconductor quantum dots,"We have studied the physical processes responsible for the spin -flip in GaAs
quantum dots. We have calculated the rates for different mechanisms which are
related to spin-orbit coupling and cause a spin-flip during the inelastic
relaxation of the electron in the dot both with and without a magnetic field.
We have shown that the zero-dimensional character of the problem when electron
wave functions are localized in all directions leads to freezing out of the
most effective spin-flip mechanisms related to the absence of the inversion
centers in the elementary crystal cell and at the heterointerface and, as a
result, to unusually low spin-flip rates.",9907367v1
2001-08-01,Order from disorder: Quantum spin gap in magnon spectra of LaTiO_3,"A theory of the anisotropic superexchange and low energy spin excitations in
a Mott insulator with t_{2g} orbital degeneracy is presented. We observe that
the spin-orbit coupling induces frustrating Ising-like anisotropy terms in the
spin Hamiltonian, which invalidate noninteracting spin wave theory. The
frustration of classical states is resolved by an order from disorder
mechanism, which selects a particular direction of the staggered moment and
generates a quantum spin gap. The theory explains well the observed magnon gaps
in LaTiO_3. As a test case, a specific prediction is made on the splitting of
magnon branches at certain momentum directions.",0108016v2
2001-08-11,Spin dynamics from time-dependent spin density-functional theory,"We derive the spin-wave dynamics of a magnetic material from the
time-dependent spin density functional theory in the linear response regime.
The equation of motion for the magnetization includes, besides the static spin
stiffness, a ""Berry curvature"" correction and a damping term. A gradient
expansion scheme based on the homogeneous spin-polarized electron gas is
proposed for the latter two quantities, and the first few coefficients of the
expansion are calculated to second order in the Coulomb interaction.",0108193v1
2003-05-19,Spin-phonon interaction and band effects in the high-T_C superconductor HgBa_2CuO_4,"Band calculations show that a stripe-like anti-ferromagnetic spin wave is
enforced by a 'half-breathing' phonon distortion within the CuO plane of
HgBa_2CuO_4. This spin-phonon coupling is increased further by shear distortion
and by increased distance between Cu and apical oxygens. The effects from
spin-phonon coupling are consistent with many observations in high-T_C
materials. Spin-phonon coupling can be important for the mechanism of spin
fluctuations and superconductivity, although the effects are quantitatively
weak when using the local density potential.",0305438v1
2003-06-23,Normal-superfluid interaction dynamics in a spinor Bose gas,"Coherent behavior of spinor Bose-Einstein condensates is studied in the
presence of a significant uncondensed (normal) component. Normal-superfluid
exchange scattering leads to a near-perfect local alignment between the spin
fields of the two components. Through this spin locking, spin-domain formation
in the condensate is vastly accelerated as the spin populations in the
condensate are entrained by large-amplitude spin waves in the normal component.
We present data evincing the normal-superfluid spin dynamics in this regime of
complicated interdependent behavior.",0306584v1
2003-07-01,Spin clustering and ferromagnetic couplings in a dilute magnetic semiconductor,"Ferromagnetic couplings in spin clusters are shown to be strongly enhanced
compared to those for an ordered impurity arrangement, even for the same spin
separation and hole doping. The consequent energy-enhancement of the
cluster-localized spin-wave modes indicates a potentially significant role of
positional Mn disorder in enhancing $T_{\rm C}$. Within a simple model
involving two spin-excitation energy scales corresponding to weakly and
strongly coupled spins, the temperature dependence of magnetization is found to
be in good agreement with the SQUID magnetization data for Ga$_{1-x}$Mn$_x$As.",0307009v1
2003-11-05,Spin nematics in the bilinear-biquadratic S=1 spin chain,"We report the existence of an extended critical, nondimerized region in the
phase diagram of the bilinear-biquadratic spin-one chain. The dominant power
law correlations are ferroquadrupolar, i.e. spin nematic in character. Another
known critical region is also characterized by dominant quadrupolar
correlations, although with a different wave vector. Our results show that spin
nematic correlations play an important role in quantum magnets with spin S >= 1
in regions between antiferromagnetic and ferromagnetic phases.",0311082v1
2004-10-01,Spin interferometry with electrons in nanostructures: A road to spintronic devices,"The wave nature of electrons in semiconductor nanostructures results in
spatial interference effects similar to those exhibited by coherent light. The
presence of spin-orbit coupling renders interference in spin space and in real
space interdependent, making it possible to manipulate the electron's spin
state by addressing its orbital degree of freedom. This suggests the utility of
electronic analogs of optical interferometers as blueprints for new spintronics
devices. We demonstrate the usefulness of this concept using the Mach-Zehnder
interferometer as an example. Its spin-dependent analog realizes a
spin-controlled field-effect transistor without magnetic contacts and may be
used as a quantum logical gate.",0410008v1
2004-10-29,How many electrons are needed to flip a local spin?,"Considering the spin of a local magnetic atom as a quantum mechanical
operator, we illustrate the dynamics of a local spin interacting with a
ballistic electron represented by a wave packet. This approach improves the
semi-classical approximation and provides a complete quantum mechanical
understanding for spin transfer phenomena. Sending spin-polarized electrons
towards a local magnetic atom one after another, we estimate the minimum number
of electrons needed to flip a local spin.",0410775v1
2005-08-30,Effects of spin current on ferromagnets,"When a spin-polarized current flows through a ferromagnet, the local
magnetization receives a spin torque. Two consequences of this spin torque are
studied. First, the uniformly magnetized ferromagnet becomes unstable if a
sufficiently large current is applied. The characteristics of the instability
include spin wave generation and magnetization chaos. Second, the spin torque
has profound effects on the structure and dynamics of the magnetic domain wall.
A detail analysis on the domain wall mass, kinetic energy and wall depinning
threshold is given.",0508735v1
2006-08-28,Inverse Spin Hall Effect by Spin Injection,"Motivated by a recent experiment[Nature {\bf 442}, 176 (2006)], we present a
quantitative microscopic theory to investigate the inverse spin-Hall effect
with spin injection into aluminum considering both intrinsic and extrinsic
spin-orbit couplings using the orthogonalized-plane-wave method. Our
theoretical results are in good agreement with the experimental data. It is
also clear that the magnitude of the anomalous Hall resistivity is mainly due
to contributions from extrinsic skew scattering, while its spatial variation is
determined by the intrinsic spin-orbit coupling.",0608594v2
2001-01-03,Collision of spinning black holes in the close limit,"In this paper we consider the collision of spinning holes using first order
perturbation theory of black holes (Teukolsky formalism). With these results
(along with ones, we published in the past) one can predict the properties of
the gravitational waves radiated from the late stage inspiral of two spinning,
equal mass black holes. Also we note that the energy radiated by the head-on
collision of two spinning holes with spins (that are equal and opposite)
aligned along the common axis is more than the case in which the spins are
perpendicular to the axis of the collision.",0101015v1
2000-07-06,Spin Structure of Many-Body Systems with Two-Body Random Interactions,"We investigate the spin structure of many-fermion systems with a
spin-conserving two-body random interaction. We find a strong dominance of
spin-0 ground states and considerable correlations between energies and wave
functions of low-lying states with different spin, but no indication of
pairing. The spectral densities exhibit spin-dependent shapes and widths, and
depend on the relative strengths of the spin-0 and spin-1 couplings in the
two-body random matrix. The spin structure of low-lying states can largely be
explained analytically.",0007013v1
2003-09-19,Spatial Localization and Relativistic Transformation of Quantum Spins,"The purity of a reduced state for spins that is pure in the rest frame will
most likely appear to degrade because spin and momentum become mixed when
viewed by a moving observer. We show that such a boost-induced decrease in spin
purity observed in a moving reference frame is intrinsically related to the
spatial localization properties of the wave package observed in the rest frame.
Furthermore, we prove that, for any localized pure state with separable spin
and momentum in the rest frame, its reduced density matrix for spins inevitably
appears to be mixed whenever viewed from a moving reference frame.",0309144v2
2004-06-02,Entanglement of electron spins in superconductors,"We investigate entanglement of two electron spins forming Cooper pairs in an
s-wave superconductor. The two-electron space-spin density matrix is obtained
from the BCS ground state using a two-particle Green's function. It is
demonstrated that a two spin state is not given by a spin singlet state but by
a Werner state. It is found that the entanglement length, within which two
spins are entangled, is not the order of the coherence length but the order of
the Fermi wave length.",0406013v1
2007-05-29,Parametric spin excitations in lateral quantum dots,"In this work, the spin dynamics of a single electron under parametric
modulation of a lateral quantum dot's electrostatic potential in the presence
of spin-orbit coupling is investigated. Numerical and theoretical calculations
demonstrate that, by squeezing and/or moving the electron's wave function, spin
rotations with Rabi frequencies on the order of tens of megahertz can be
achieved with experimentally accessible parameters in both parabolic and square
lateral quantum dots. Applications of parametric excitations for determining
spin-orbit coupling parameters and for increasing the spin polarization in the
electronic ground are demonstrated.",0705.4231v2
2007-10-16,Influences of an impurity on the transport properties of one-dimensional antisymmetric spin filter,"The influences of an impurity on the spin and the charge transport of
one-dimensional antisymmetric spin filter are investigated using bosonization
and Keldysh formulation and the results are highlighted against those of
spinful Luttinger liquids. Due to the dependence of the electron spin
orientation on wave number the spin transport is not affected by the impurity,
while the charge transport is essentially identical with that of spinless
one-dimensional Luttinger liquid.",0710.3088v1
2008-05-09,"Spin dynamics in (III,Mn)V ferromagnetic semiconductors: the role of correlations","We address the role of correlations between spin and charge degrees of
freedom on the dynamical properties of ferromagnetic systems governed by the
magnetic exchange interaction between itinerant and localized spins. For this
we introduce a general theory that treats quantum fluctuations beyond the
Random Phase Approximation based on a correlation expansion of the Green's
function equations of motion. We calculate the spin susceptibility, spin--wave
excitation spectrum, and magnetization precession damping. We find that
correlations strongly affect the magnitude and carrier concentration dependence
of the spin stiffness and magnetization Gilbert damping.",0805.1320v2
2009-05-15,Spin polarization of half-quantum vortex in systems with equal spin pairing,"We present a variational analysis for a half-quantum vortex (HQV) in the
equal-spin-pairing superfluid state which, under suitable conditions, is
believed to be realized in Sr2RuO4 and 3He-A. Our approach is based on a
description of the HQV in terms of a BCS-like wave function with a
spin-dependent boost. We predict a novel feature: the HQV, if stable, should be
accompanied by a non-zero spin polarization. Such a spin polarization would
exist in addition to the one induced by the Zeeman coupling to the external
field and hence may serve as an indicator in experimental search for HQV.",0905.2631v1
2009-10-30,Gravitational waveforms from unequal-mass binaries with arbitrary spins under leading order spin-orbit coupling,"The paper generalizes the structure of gravitational waves from orbiting
spinning binaries under leading order spin-orbit coupling, as given in the work
by K\""onigsd\""orffer and Gopakumar [PRD 71, 024039 (2005)] for single-spin and
equal-mass binaries, to unequal-mass binaries and arbitrary spin
configurations. The orbital motion is taken to be quasi-circular and the
fractional mass difference is assumed to be small against one. The emitted
gravitational waveforms are given in analytic form.",0910.5931v2
2010-03-22,Dynamical central peak and spinon deconfinement in frustrated spin chains,"Studying the dynamical spin structure factor in frustrated spin chains with
spontaneously dimerized ground state we show that besides the gapped spin-wave
excitations there appears at finite temperatures also a sharp central peak. The
latter can be attributed to deconfined spinons, accounted well within the
variational approach. The central peak remains well pronounced within the local
spin dynamics and may be relevant for experiments on materials with 1D
frustrated spin chains.",1003.4232v1
2010-05-24,Application of entanglement conditions to spin systems,"There have been numerous studies of entanglement in spin systems. These have
usually focussed on examining the entanglement between individual spins or
determining whether the state of the system is completely separable. Here we
present conditions that allow us to determine whether blocks of spins are
entangled. We show that sometimes these conditions can detect entanglement
better than conditions involving individual spins. We apply these conditions to
study entanglement in spin wave states, both when there are only a few magnons
present and also at finite temperature.",1005.4448v1
2013-03-07,Thickness dependence of the degree of spin polarization of the electrical current in permalloy thin films,"Spin-polarized electrical transport is investigated in $
Al_{2}O_{3}/Ni_{80}Fe_{20}/Al_{2}O_{3}$ thin films for permalloy thickness
between 6 and 20nm. The degree of spin-polarization of the current flowing in
the plane of the film is measured through the current induced spin wave Doppler
shift. We find that it decreases as the film thickness decreases, from 0.72 at
20nm to 0.46 at 6nm. This decrease is attributed to a spin depolarization
induced by the film surfaces. A model is proposed which takes into account the
contributions of the different sources of electron scattering (alloy disorder,
phonons, thermal magnons, grain boundaries, film surfaces) to the measured
spin-dependent resistivities.",1303.1692v1
2013-08-26,Ferromagnetic spin-orbital liquid of dipolar fermions in zigzag lattices,"Two-component dipolar fermions in zigzag optical lattices allow for the
engineering of spin-orbital models. We show that dipolar lattice fermions
permit the exploration of a regime typically unavailable in solid-state
compounds that is characterized by a novel spin-liquid phase with a finite
magnetization and spontaneously broken SU(2) symmetry. This peculiar spin
liquid may be understood as a Luttinger liquid of composite particles
consisting of bound states of spin waves and orbital domain walls moving in an
unsaturated ferromagnetic background. In addition, we show that the system
exhibits a boundary phase transitions involving non-local entanglement of edge
spins.",1308.5519v1
2013-09-02,Proposal for a local heating driven spin current generator,"We propose a two-terminal spin-orbit interferometer with a hot molecule
inserted in one of its arms to generate pure spin currents. Local heating is
achieved by coupling the vibrational modes of the molecule to a third
(phononic) reservoir. We show that this spin calorimetric effect is due to the
combined influence of spin-dependent wave interference and inelastic
scattering. Remarkably, the device converts heat flow into spin-polarized
current even without applying any voltage or temperature difference to the
electronic terminals.",1309.0366v1
2021-04-05,Thermal Hall Effect of Chiral Spin Fluctuations,"Using a two-dimensional square lattice Heisenberg model with a Rashba-type
Dzyaloshinskii-Moriya interaction, we demonstrate that chiral spin fluctuations
can give rise to a thermal Hall effect in the absence of any static spin
texture or momentum space topology. It is shown by means of Monte Carlo and
stochastic spin dynamics simulations that the thermal Hall response is finite
at elevated temperature outside of the linear spin wave regime and consistent
with the presence of thermal fluctuation-induced nontrivial topology. Our
result suggests that the high-fluctuation phases outside of the conventional
regime of magnonics may yet be a promising area of exploration for spin-based
electronics.",2104.02168v1
2003-12-29,"Spin-Orbit Ordering, Momentum Space Coexistence, and Cuprate Superconductivity","Motivated by the energetic advantage of achieving coherent enhancement of
effective spin-dependent interactions through approximate nesting, we propose
specific forms of spin ordering, whose form varies over the Fermi surface, for
the cuprate superconductors. Competing ""spin-orbit"" orderings involving order
parameters in spatial $d_{x^2-y^2}$ and $d_{xy}$ waves at commensurate and
incommensurate wavevectors, phase separated in momentum space, support behavior
suggestive of observed phenomena. The $d_{xy}$ spin-orbit fluctuation induces
an effective interaction that favors $d_{x^2-y^2}$-wave pairing, as required
for the observed superconductivity. Anisotropic spin susceptibility is a
crucial prediction of our mechanism.",0312685v1
2008-07-16,Upper and lower limits on the Crab pulsar's astrophysical parameters set from gravitational wave observations by LIGO: braking index and energy considerations,"The Laser Interferometer Gravitational Observatory (LIGO) has recently
reached the end of its fifth science run (S5), having collected more than a
year worth of data. Analysis of the data is still ongoing but a positive
detection of gravitational waves, while possible, is not realistically expected
for most likely sources. This is particularly true for what concerns
gravitational waves from known pulsars. In fact, even under the most optimistic
(and not very realistic) assumption that all the pulsar's observed spin-down is
due to gravitational waves, the gravitational wave strain at earth from all the
known isolated pulsars (with the only notable exception of the Crab pulsar)
would not be strong enough to be detectable by existing detectors. By August
2006, LIGO had produced enough data for a coherent integration capable to
extract signal from noise that was weaker than the one expected from the Crab
pulsar's spin-down limit. No signal was detected, but beating the spin-down
limit is a considerable achievement for the LIGO Scientific Collaboration
(LSC). It is customary to translate the upper limit on strain from a pulsar
into a more astrophysically significant upper limit on ellipticity. Once the
spin-down limit has been beaten, it is possible to release the constraint that
all the spin-down is due to gravitational wave emission. A more complete model
with diverse braking mechanisms can be used to set limits on several
astrophysical parameters of the pulsar. This paper shows possible values of
such parameters for the Crab pulsar given the current limit on gravitational
waves from this neutron star.",0807.2485v1
2010-08-10,Numerical study of the spin-1/2 Heisenberg antiferromagnet on a 48-site triangular lattice,"We numerically study the magnetization and the dispersion relation of a
frustrated quantum spin system. Our method, which is named the stochastic state
selection method, is a kind of Monte Carlo method to give eigenstates of the
system through statistical averaging processes.
  Using the stochastic state selection method with some constraints, we make a
successful study of the spin-1/2 Heisenberg antiferromagnet on a 48-site
triangular lattice. We calculate the sublattice magnetization and the static
structure function in the ground state. Our result on the sublattice
magnetization is consistent with the value given by the linear spin wave
theory. This adds an evidence for the analysis based on the spontaneous
symmetry breaking of the semi-classical Neel order in the ground state.
  We also evaluate the low-lying one magnon spectra of the model with all wave
vectors available on a 48-site triangular lattice. We find that at the ordering
wave vector there is a Goldstone mode, which is in good agreement with the
result from the spin wave analysis. The magnon spectra with other wave vectors,
however, are quite different from results obtained by the linear spin wave
theory. We observe a flat dispersion relation with a strong downward
renormalization. Our results are compatible with those recently reported in the
series expansion study and in the order 1/S calculation of the spin wave
analysis.",1008.1612v1
2014-09-24,Angular Momentum Transport via Internal Gravity Waves in Evolving Stars,"Recent asteroseismic advances have allowed for direct measurements of the
internal rotation rates of many sub-giant and red giant stars. Unlike the
nearly rigidly rotating Sun, these evolved stars contain radiative cores that
spin faster than their overlying convective envelopes, but slower than they
would in the absence of internal angular momentum transport. We investigate the
role of internal gravity waves in angular momentum transport in evolving low
mass stars. In agreement with previous results, we find that convectively
excited gravity waves can prevent the development of strong differential
rotation in the radiative cores of Sun-like stars. As stars evolve into
sub-giants, however, low frequency gravity waves become strongly attenuated and
cannot propagate below the hydrogen burning shell, allowing the spin of the
core to decouple from the convective envelope. This decoupling occurs at the
base of the sub-giant branch when stars have surface temperatures of roughly
5500 K. However, gravity waves can still spin down the upper radiative region,
implying that the observed differential rotation is likely confined to the deep
core near the hydrogen burning shell. The torque on the upper radiative region
may also prevent the core from accreting high-angular momentum material and
slow the rate of core spin-up. The observed spin-down of cores on the red giant
branch cannot be totally attributed to gravity waves, but the waves may enhance
shear within the radiative region and thus increase the efficacy of
viscous/magnetic torques.",1409.6835v1
2019-06-12,Frequency-Division Multiplexing in Magnonic Logic Networks Based on Caustic-Like Spin-Wave Beams,"Wave-based data processing by spin waves and their quanta, magnons, is a
promising technique to overcome the challenges which CMOS-based logic networks
are facing nowadays. The advantage of these quasi-particles lies in their
potential for the realization of energy efficient devices on the micro- to
nanometer scale due to their charge-less propagation in magnetic materials. In
this paper, the frequency dependence of the propagation direction of
caustic-like spin-wave beams in microstructured ferromagnets is studied by
micromagnetic simulations. Based on the observed alteration of the propagation
angle, an approach to spatially combine and separate spin-wave signals of
different frequencies is demonstrated. The presented magnetic structure
constitutes a prototype design of a passive circuit enabling frequency-division
multiplexing in magnonic logic networks. It is verified that spin-wave signals
of different frequencies can be transmitted through the device simultaneously
without any interaction or creation of spurious signals. Due to the wave-based
approach of computing in magnonic networks, the technique of frequency-division
multiplexing can be the basis for parallel data processing in single magnonic
devices, enabling the multiplication of the data throughput.",1906.04993v2
2021-04-14,Finite-element dynamic-matrix approach for spin-wave dispersions in magnonic waveguides with arbitrary cross section,"We present a numerical approach to efficiently calculate spin-wave
dispersions and spatial mode profiles in magnetic waveguides of arbitrarily
shaped cross section with any non-collinear equilibrium magnetization which is
translationally invariant along the waveguide. Our method is based on the
propagating-wave dynamic-matrix approach by Henry et al. and extends it to
arbitrary cross sections using a finite-element method. We solve the linearized
equation of motion of the magnetization only in a single waveguide cross
section which drastically reduces computational effort compared to common
three-dimensional micromagnetic simulations. In order to numerically obtain the
dipolar potential of individual spin-wave modes, we present a plane-wave
version of the hybrid finite-element/boundary-element method by Frekdin and
Koehler which, for the first time, we extend to a modified version of the
Poisson equation. Our method is applied to several important examples of
magnonic waveguides including systems with surface curvature, such as magnetic
nanotubes, where the curvature leads to an asymmetric spin-wave dispersion. In
all cases, the validity of our approach is confirmed by other methods. Our
method is of particular interest for the study of curvature-induced or
magnetochiral effects on spin-wave transport but also serves as an efficient
tool to investigate standard magnonic problems.",2104.06943v1
2020-01-24,Dynamics of Spiral Spin Waves in Magnetic Nano-patches: Influence of Thickness and Shape,"We explore the dynamics of spiral spin waves in Permalloy nano-elements with
variable aspect ratio of geometric dimensions, and their potential use as
improved spin wave emitters with no or little biasing field required. Numerical
results show that above a certain thickness, propagating spiral waves can be
obtained in circular and square shaped elements in a flux closure state.
VNA-FMR experiments on 20 nm (thin) and 80 nm (thick) samples confirm two type
of spectra corresponding to different dispersions for thinner and thicker
elements. We show that, for the thicker films, the vortex core region acts as a
source of large amplitude spiral spin waves, which dominate over other modes.
In case of the thinner elements, these modes are critically damped. For
different shapes of the patch, we show that a rich collection of confined
propagating modes can also be excited, modifying the final wave front and
enriching the potential of the nano-dot as a spin wave emitter. We give an
explanation for the intense spiral modes from the perspective of a balance of
dipolar and exchange energies in the sample.",2001.09053v1
2022-03-10,"Momentum, angular momentum, and spin of waves in an isotropic collisionless plasma","We examine the momentum and angular momentum (including spin) properties of
linear waves, both longitudinal (Langmuir) and transverse (electromagnetic), in
an isotropic nonrelativistic collisionless electron plasma. We focus on
conserved quantities associated with the translational and rotational
invariance of the wave fields with respect to the homogeneous medium; these are
sometimes called pseudo-momenta. There are two types of the momentum and
angular momentum densities: (i) the kinetic ones associated with the energy
flux density and the symmetrized (Belinfante) energy-momentum tensor and (ii)
the canonical ones associated with the conserved Noether currents and canonical
energy-momentum tensor. We find that the canonical momentum and spin densities
of Langmuir waves are similar to those of sound waves in fluids or gases; they
are expressed via the electron velocity field. In turn, the momentum and spin
densities of electromagnetic waves can be written either in the forms known for
free-space electromagnetic fields, involving only the electric field, or in the
dual-symmetric forms involving both electric and magnetic fields, as well as
the effective permittivity of plasma. We derive these properties both within
the phenomenological macroscopic approach and microscopic Lagrangian field
theory for the coupled electromagnetic fields and electrons. Finally, we
explore implications of the canonical momentum and spin densities in transport
and electrodynamic phenomena: the Stokes drift, the wave-induced magnetization
(inverse Faraday effect), etc.",2203.05240v2
2011-01-27,Magnetic excitations in one-dimensional spin-orbital models,"We study the dynamics and thermodynamics of one-dimensional spin-orbital
models relevant for transition metal oxides. We show that collective spin,
orbital, and combined spin-orbital excitations with infinite lifetime can
exist, if the ground state of both sectors is ferromagnetic. Our main focus is
the case of effectively ferromagnetic (antiferromagnetic) exchange for the spin
(orbital) sector, respectively, and we investigate the renormalization of spin
excitations via spin-orbital fluctuations using a boson-fermion representation.
We contrast a mean-field decoupling approach with results obtained by treating
the spin-orbital coupling perturbatively. Within the latter self-consistent
approach we find a significant increase of the linewidth and additional
structures in the dynamical spin structure factor as well as Kohn anomalies in
the spin-wave dispersion caused by the scattering of spin excitations from
orbital fluctuations. Finally, we analyze the specific heat c(T) by comparing a
numerical solution of the model obtained by the density-matrix renormalization
group with perturbative results. At low temperatures T we find numerically c(T)
T pointing to a low-energy effective theory with dynamical critical exponent
z=1.",1101.5301v1
2011-05-21,Quantum states and linear response in dc and electromagnetic fields for charge current and spin polarization of electrons at Bi/Si interface with giant spin-orbit coupling,"An expansion of the nearly free-electron model constructed by Frantzeskakis,
Pons and Grioni [Phys. Rev. B {\bf 82}, 085440 (2010)] describing quantum
states at Bi/Si(111) interface with giant spin-orbit coupling is developed and
applied for the band structure and spin polarization calculation, as well as
for the linear response analysis for charge current and induced spin caused by
dc field and by electromagnetic radiation. It is found that the large
spin-orbit coupling in this system may allow resolving the spin-dependent
properties even at room temperature and at realistic collision rate. The
geometry of the atomic lattice combined with spin-orbit coupling leads to an
anisotropic response both for current and spin components related to the
orientation of the external field. The in-plane dc electric field produces only
the in-plane components of spin in the sample while both the in-plane and
out-of-plane spin components can be excited by normally propagating
electromagnetic wave with different polarizations.",1105.4215v1
2013-04-17,Universal spin dynamics in two-dimensional Fermi gases,"Harnessing spins as carriers for information has emerged as an elegant
extension to the transport of electrical charges. The coherence of such spin
transport in spintronic circuits is determined by the lifetime of spin
excitations and by spin diffusion. Fermionic quantum gases are a unique system
to study the fundamentals of spin transport from first principles since
interactions can be precisely tailored and the dynamics is on time scales which
are directly observable. In particular at unitarity, spin transport is dictated
by diffusion and is expected to reach a universal, quantum-limited diffusivity
on the order of hbar/m. Here, we study the non-equilibrium dynamics of a
two-dimensional Fermi gas following a quench into a metastable, transversely
polarized spin state. Using the spin-echo technique, we measure the yet lowest
transverse spin diffusion constant of 0.25(3) hbar/m. For weak interactions, we
observe a coherent collective transverse spin-wave mode that exhibits mode
softening when approaching the hydrodynamic regime.",1304.4980v1
2015-07-15,Spin photonics and spin-photonic devices with dielectric metasurfaces,"Dielectric metasurfaces with spatially varying birefringence and high
transmission efficiency can exhibit exceptional abilities for controlling the
photonic spin states. We present here some of our works on spin photonics and
spin-photonic devices with metasurfaces. We develop a hybrid-order Poincare
sphere to describe the evolution of spin states of wave propagation in the
metasurface. Both the Berry curvature and the Pancharatnam-Berry phase on the
hybrid-order Poincare sphere are demonstrated to be proportional to the
variation of total angular momentum. Based on the spin-dependent property of
Pancharatnam-Berry phase, we find that the photonic spin Hall effect can be
observed when breaking the rotational symmetry of metasurfaces. Moreover, we
show that the dielectric metasurfaces can provide great flexibility in the
design of novel spin-photonic devices such as spin filter and spin-dependent
beam splitter.",1507.04064v2
2017-09-01,Scaling of the Rashba spin-orbit torque in magnetic domain walls,"Spin-orbit torque in magnetic domain walls was investigated by solving the
Pauli-Schr\""{o}dinger equation for the itinerant electrons. The Rashba
interaction considered is derived from the violation of inversion symmetry at
interfaces between ferromagnets and heavy metals. In equilibrium, the Rashba
spin-orbit interaction gives rise to a torque corresponding to the
Dzyaloshinskii-Moriya interaction. When there is a current flowing, the
spin-orbit torque experienced by the itinerant electrons in short domain walls
has both field-like and damping-like components. However, when the domain wall
width is increased, the damping-like component, which is the counterpart of the
non-adiabatic spin transfer torque, decreases rapidly at the domain wall
center. In contrast to the non-adiabatic spin transfer torque, the damping-like
spin-orbit torque does not approach to zero far away from the domain wall
center, even in the adiabatic limit. The scattering of spin-up and spin-down
wave functions, which is caused by the Rashba spin-orbit interaction and the
spatial variation of magnetization profile in the domain wall, gives rise to
the finite damping-like spin-orbit torque.",1709.00187v3
2019-11-06,High spin mixing conductance and spin interface transparency at $Co_2Fe_{0.4}Mn_{0.6}Si$ Heusler alloy and Pt interface,"Ferromagnetic materials exhibiting low magnetic damping ($\alpha$) and
moderately high saturation magnetization are required from the viewpoints of
generation, transmission and detection of spin wave. Since spin-to-charge
conversion efficiency is another important parameter, high spin mixing
conductance ($g_{r}^{\uparrow \downarrow}$) is the key for efficient
spin-to-charge conversion. Full Heusler alloys e.g. $Co_2Fe_{0.4}Mn_{0.6}Si$
(CFMS), which are predicted to be 100$\%$ spin polarized, possess low $\alpha$.
However, the $g_{r}^{\uparrow \downarrow}$ at the interface between CFMS and a
paramagnet has not fully been understood. Here, we report the investigations of
spin pumping and inverse spin Hall effect in $CFMS/Pt$ bilayers. Damping
analysis indicates the presence of significant spin pumping at the interface of
CFMS and Pt, which is also confirmed by the detection of inverse spin Hall
voltage. We show that in CFMS/Pt the $g_{r}^{\uparrow \downarrow}$
(1.77$\times$10$^{20}$m$^{-2}$) and interface transparency (84$\%$) are higher
compared to values reported for other ferromagnet/heavy metal systems.",1911.02230v1
2014-06-04,Long-lived spin plasmons in a spin-polarized two-dimensional electron gas,"Collective charge-density modes (plasmons) of the clean two-dimensional
unpolarized electron gas are stable, for momentum conservation prevents them
from decaying into single-particle excitations. Collective spin-density modes
(spin plasmons) possess no similar protection and rapidly decay by production
of electron-hole pairs. Nevertheless, if the electron gas has a sufficiently
high degree of spin polarization ($P>1/7$, where $P$ is the ratio of the
equilibrium spin density and the total electron density, for a parabolic
single-particle spectrum) we find that a long-lived spin-plasmon---a collective
mode in which the densities of up and down spins oscillate with opposite
phases---can exist within a ""pseudo gap"" of the single-particle excitation
spectrum. The ensuing collectivization of the spin excitation spectrum is quite
remarkable and should be directly visible in Raman scattering experiments. The
predicted mode could dramatically improve the efficiency of coupling between
spin-wave-generating devices, such as spin-torque oscillators.",1406.0986v2
2018-12-10,A Spin-Optical Nano Device,"The photon spin is an important resource for quantum information processing
as is the electron spin in spintronics. However, for subwavelength confined
optical excitations, polarization as a global property of a mode cannot be
defined. Here, we show that any polarization state of a plane-wave photon can
reversibly be mapped to a pseudo-spin embodied by the two fundamental modes of
a subwavelength plasmonic two-wire transmission line. We design a device in
which this pseudo-spin evolves in a well-defined fashion throughout the device
reminiscent of the evolution of photon polarization in a birefringent medium
and the behaviour of electron spins in the channel of a spin field-effect
transistor. The significance of this pseudo-spin is enriched by the fact that
it is subject to spin-orbit locking. Combined with optically active materials
to exert external control over the pseudo-spin precession, our findings could
enable spin-optical transistors, i.e. the routing and processing of quantum
information with light on a subwavelength scale.",1812.03721v1
2019-05-19,Persistent spin helix in Rashba-Dresselhaus ferroelectric CsBiNb2O7,"Ferroelectric Rashba semiconductors (FERSC) are a novel class of
multifunctional materials showing a giant Rashba spin splitting which can be
reversed by switching the electric polarization. Although they are excellent
candidates as channels in spin field effect transistors, the experimental
research has been limited so far to semiconducting GeTe, in which ferroelectric
switching is often prevented by heavy doping and/or large leakage currents.
Here, we report that CsBiNb2O7, a layered perovskite of Dion-Jacobson type, is
a robust ferroelectric with sufficiently strong spin-orbit coupling and spin
texture reversible by electric field. Moreover, we reveal that its topmost
valence band's spin texture is quasi-independent from the momentum, as a result
of the low symmetry of its ferroelectric phase. The peculiar spin polarization
pattern in the momentum space may yield the so-called ""persistent spin helix"",
a specific spin-wave mode which protects the spin from decoherence in diffusive
transport regime, potentially ensuring a very long spin lifetime in this
material.",1905.07744v2
2017-03-27,Spin-incoherent Luttinger liquid of one-dimensional spin-1 Tonks-Girardeau Bose gas: Spin-dependent properties,"Spin-incoherent Luttinger liquid (SILL) is a different universal class from
the Luttinger liquid.\ This difference results from the spin incoherence of the
system when the thermal energy of the system is higher than the spin excitation
energy.\ We consider one-dimensional spin-$1$ Bose gas in the SILL regime and
investigate its spin-dependent many-body properties.\ In Tonks-Girardeau limit,
we are able to write down the general wave functions in a harmonic trap.\ We
numerically calculate the spin-dependent (spin-plus, minus, and $0$) momentum
distributions in the sector of zero magnetization which allows to demonstrate
the most significant spin-incoherent feature compared to the spinless or
spin-polarized case.\ In contrast to the spinless Bose gas, the momentum
distributions are broadened and in the large momentum limit follow the same
asymptotic $1/p^4$ dependence but with reduced coefficients.\ While the density
matrices and momentum distributions differ between different spin components
for small $N$, at large $N$ they approach each other.\ We show these by
analytic arguments and numerical calculations up to $N$ $=$ $16$.",1703.08949v1
2021-09-01,Triplon current generation in solids,"A triplon refers to a fictitious particle that carries angular momentum $S =
1$ corresponding to the elementary excitation in a broad class of quantum
dimerized spin systems. Such systems without magnetic order have long been
studied as a testing ground for quantum properties of spins. Although triplons
have been found to play a central role in thermal and magnetic properties in
dimerized magnets with singlet correlation, a spin angular momentum flow
carried by triplons, a triplon current, has not been detected yet. Here we
report spin Seebeck effects induced by a triplon current: triplon spin Seebeck
effect, using a spin-Peierls system CuGeO$_3$. The result shows that the
heating-driven triplon transport induces spin current whose sign is positive,
opposite to the spin-wave cases in magnets. The triplon spin Seebeck effect
persists far below the spin-Peierls transition temperature, being consistent
with a theoretical calculation for triplon spin Seebeck effects.",2109.00352v1
2022-11-24,Elastic Valley Spin Controlled Chiral Coupling in Topological Valley Phononic Crystals,"Distinct from the phononic valley pseudo-spin, the real physical spin of
elastic waves adds a novel tool-kit capable of envisaging the valley-spin
physics of topological valley phononic crystals from a local viewpoint. Here,
we report the observation of local elastic valley spin as well as the hidden
elastic spin-valley locking mechanism overlooked before. We demonstrate that
the selective one-way routing of valley phonon states along the topological
interface can be reversed by imposing the elastic spin meta-source at different
interface locations with opposite valley-spin correspondence. We unveil the
physical mechanism of selective directionality as the elastic spin controlled
chiral coupling of valley phonon states, through both analytical theory and
experimental measurement of the opposite local elastic spin density at
different interface locations for different transport directions. The elastic
spin of valley topological edge phonons can be extended to other topological
states and offers new tool to explore topological metamaterials.",2211.15389v1
2012-08-06,Microscopic theory for the Doppler velocimetry of spin propagation in semiconductor quantum wells,"We provide a microscopic theory for the Doppler velocimetry of spin
propagation in the presence of spatial inhomogeneity, driving electric field
and the spin orbit coupling in semiconductor quantum wells in a wide range of
temperature regime based on the kinetic spin Bloch equation. It is analytically
shown that under an applied electric field, the spin density wave gains a
time-dependent phase shift $\phi(t)$. Without the spin-orbit coupling, the
phase shift increases linearly with time and is equivalent to a normal Doppler
shift in optical measurements. Due to the joint effect of spin-orbit coupling
and the applied electric field, the phase shift behaviors differently at the
early and the later stages. At the early stage, the phase shifts are the same
with or without the spin-orbit coupling. While at the later stage, the phase
shift deviates from the normal Doppler one when the spin-orbit coupling is
present. The crossover time from the early normal Doppler behavior to the
anomalous one at the later stage is inversely proportional to the spin
diffusion coefficient, wave vector of the spin density wave and the spin-orbit
coupling strength. In the high temperature regime, the crossover time becomes
large as a result of the decreased spin diffusion coefficient. The analytic
results capture all the quantitative features of the experimental results,
while the full numerical calculations agree quantitatively well with the
experimental data obtained from the Doppler velocimetry of spin propagation
[Yang {\it et al.}, Nat. Phys. {\bf 8}, 153 (2012)]. We further predict that
the coherent spin precession, originally thought to be broken down at high
temperature, is robust up to the room temperature for narrow quantum wells. We
point out that one has to carry out the experiments longer to see the effect of
the coherent spin precession at higher temperature due to the larger crossover
time.",1208.1081v2
2016-02-09,Characterizing the parent Hamiltonian for a complete set of orthogonal wave functions: An inverse quantum problem,"We study the inverse problem of constructing an appropriate Hamiltonian from
a physically reasonable set of orthogonal wave functions for a quantum spin
system. Usually, we are given a local Hamiltonian and try to characterize the
relevant wave functions and energies (the spectrum) of the system. Here, we
take the opposite approach; starting from a collection of orthogonal wave
functions, our goal is to characterize the associated parent Hamiltonian, to
see how the wave functions and the energy values determine the structure of the
parent Hamiltonian. Specifically, we obtain (quasi) local Hamiltonians by a
complete set of (multilayer) product states and a local mapping of the energy
values to the wave functions. On the other hand, a complete set of tree wave
functions (having a tree structure) results to nonlocal Hamiltonians and
operators which flip simultaneously all the spins in a single branch of the
tree graph. We observe that even for a given set of wave functions, the energy
spectrum can significantly change the nature of interactions in the
Hamiltonian. These effects can be exploited in a quantum engineering problem
optimizing an objective functional of the Hamiltonian.",1602.03120v2
2016-12-19,Extending geometrical optics: A Lagrangian theory for vector waves,"Even when neglecting diffraction effects, the well-known equations of
geometrical optics (GO) are not entirely accurate. Traditional GO treats wave
rays as classical particles, which are completely described by their
coordinates and momenta, but vector-wave rays have another degree of freedom,
namely, their polarization. The polarization degree of freedom manifests itself
as an effective (classical) ""wave spin"" that can be assigned to rays and can
affect the wave dynamics accordingly. A well-known manifestation of
polarization dynamics is mode conversion, which is the linear exchange of
quanta between different wave modes and can be interpreted as a rotation of the
wave spin. Another, less-known polarization effect is the polarization-driven
bending of ray trajectories. This work presents an extension and reformulation
of GO as a first-principle Lagrangian theory, whose effective-gauge Hamiltonian
governs the aforementioned polarization phenomena simultaneously. As an
example, the theory is applied to describe the polarization-driven divergence
of right-hand and left-hand circularly polarized electromagnetic waves in
weakly magnetized plasma.",1612.06184v2
2001-12-12,Quantum Effects and Broken Symmetries in Frustrated Antiferromagnets,"We investigate the interplay between frustration and zero-point quantum
fluctuations in the ground state of the triangular and $J_1{-}J_2$ Heisenberg
antiferromagnets, using finite-size spin-wave theory, exact diagonalization,
and quantum Monte Carlo methods. In the triangular Heisenberg antiferromagnet,
by performing a systematic size-scaling analysis, we have obtained strong
evidences for a gapless spectrum and a finite value of the thermodynamic order
parameter, thus confirming the existence of long-range N\'eel order.The good
agreement between the finite-size spin-wave results and the exact and quantum
Monte Carlo data also supports the reliability of the spin-wave expansion to
describe both the ground state and the low-energy spin excitations of the
triangular Heisenberg antiferromagnet. In the $J_1{-}J_2$ Heisenberg model, our
results indicate the opening of a finite gap in the thermodynamic excitation
spectrum at $J_2/J_1 \simeq 0.4$, marking the melting of the antiferromagnetic
N\'eel order and the onset of a non-magnetic ground state. In order to
characterize the nature of the latter quantum-disordered phase we have computed
the susceptibilities for the most important crystal symmetry breaking
operators. In the ordered phase the effectiveness of the spin-wave theory in
reproducing the low-energy excitation spectrum suggests that the uniform spin
susceptibility of the model is very close to the linear spin-wave prediction.",0112207v1
1997-10-31,Non-precessional spin-orbit effects on gravitational waves from inspiraling compact binaries to second post-Newtonian order,"We derive all second post-Newtonian (2PN), non-precessional effects of spin-
orbit coupling on the gravitational wave forms emitted by an inspiraling binary
composed of spinning, compact bodies in a quasicircular orbit. Previous post-
Newtonian calculations of spin-orbit effects (at 1.5PN order) relied on a fluid
description of the spinning bodies. We simplify the calculations by introducing
into post-Newtonian theory a delta-function description of the influence of the
spins on the bodies' energy-momentum tensor. This description was recently used
by Mino, Shibata, and Tanaka (MST) in Teukolsky-formalism analyses of particles
orbiting massive black holes, and is based on prior work by Dixon. We compute
the 2PN contributions to the wave forms by combining the MST energy-momentum
tensor with the formalism of Blanchet, Damour, and Iyer for evaluating the
binary's radiative multipoles, and with the well-known 1.5PN order equations of
motion for the binary. Our results contribute at 2PN order only to the
amplitudes of the wave forms. The secular evolution of the wave forms' phase,
the quantity most accurately measurable by LIGO, is not affected by our results
until 2.5PN order, at which point other spin-orbit effects also come into play.
We plan to evaluate the entire 2.5PN spin-orbit contribution to the secular
phase evolution in a future paper, using the techniques of this paper.",9710134v1
2000-10-18,The phase of a quantum mechanical particle in curved spacetime,"We investigate the quantum mechanical wave equations for free particles of
spin 0,1/2,1 in the background of an arbitrary static gravitational field in
order to explicitly determine if the phase of the wavefunction is $S/\hbar =
\int p_{\mu} dx^{\mu} / \hbar$, as is often quoted in the literature. We work
in isotropic coordinates where the wave equations have a simple managable form
and do not make a weak gravitational field approximation. We interpret these
wave equations in terms of a quantum mechanical particle moving in medium with
a spatially varying effective index of refraction. Due to the first order
spatial derivative structure of the Dirac equation in curved spacetime, only
the spin 1/2 particle has \textit{exactly} the quantum mechanical phase as
indicated above. The second order spatial derivative structure of the spin 0
and spin 1 wave equations yield the above phase only to lowest order in
$\hbar$. We develop a WKB approximation for the solution of the spin 0 and spin
1 wave equations and explore amplitude and phase corrections beyond the lowest
order in $\hbar$. For the spin 1/2 particle we calculate the phase appropriate
for neutrino flavor oscillations.",0010065v1
2010-10-13,Electric-field control of spin waves at room temperature in multiferroic BiFeO3,"To face the challenges lying beyond current CMOS-based technology, new
paradigms for information processing are required. Magnonics proposes to use
spin waves to carry and process information, in analogy with photonics that
relies on light waves, with several advantageous features such as potential
operation in the THz range and excellent coupling to spintronics. Several
magnonic analog and digital logic devices have been proposed, and some
demonstrated. Just as for spintronics, a key issue for magnonics is the large
power required to control/write information (conventionally achieved through
magnetic fields applied by strip lines, or by spin transfer from large
spin-polarized currents). Here we show that in BiFeO3, a room-temperature
magnetoelectric material, the spin wave frequency (>600 GHz) can be tuned
electrically by over 30%, in a non-volatile way and with virtually no power
dissipation. Theoretical calculations indicate that this effect originates from
a linear magnetoelectric effect related to spin-orbit coupling induced by the
applied electric field. We argue that these properties make BiFeO3 a promising
medium for spin wave generation, conversion and control in future magnonics
architectures.",1010.2678v1
2021-05-12,Coherent spin-wave transport in an antiferromagnet,"Magnonics is a research field complementary to spintronics, in which the
quanta of spin waves (magnons) replace electrons as information carriers,
promising less energy dissipation. The development of ultrafast nanoscale
magnonic logic circuits calls for new tools and materials to generate coherent
spin waves with frequencies as high, and wavelengths as short, as possible.
Antiferromagnets can host spin waves at THz frequencies and are therefore seen
as a future platform for the fastest and the least dissipative transfer of
information. However, the generation of short-wavelength coherent propagating
magnons in antiferromagnets has so far remained elusive. Here we report the
efficient emission and detection of a nanometer-scale wavepacket of coherent
propagating magnons in antiferromagnetic DyFeO3 using ultrashort pulses of
light. The subwavelength nanoscale confinement of the laser field due to large
absorption creates a strongly non-uniform spin excitation profile, thereby
enabling the propagation of a broadband continuum of coherent THz spin waves.
The wavepacket features magnons with detected wavelengths down to 125 nm and
supersonic velocities up to 13 km/s that propagate over macroscopic distances.
The long-sought source of coherent short-wavelength spin carriers demonstrated
here opens up new prospects for THz antiferromagnetic magnonics and coherence
mediated logic devices at THz frequencies.",2105.05886v1
2001-09-07,"Double quantum dots: interdot interactions, co-tunneling, and Kondo resonances without spin","We show that through an interdot off-site electron correlation in a double
quantum-dot (DQD) device, Kondo resonances emerge in the local density of
states without the electron spin-degree of freedom. We identify the physical
mechanism behind this phenomenon: rather than forming a spin singlet in the
device as required in the conventional Kondo physics, we found that exchange of
electron position between the two quantum dots, together with the off-site
Coulomb interaction, are sufficient to induce the Kondo resonance. Due to
peculiar co-tunneling events, the Kondo resonance in one dot may be pinned at
the chemical potential of the other one.",0109145v1
2002-11-20,Polarized Magnetic Wire Induced by Tunneling Through a Magnetic Impurity,"Using the zero mode method we compute the conductance of a wire consisting of
a magnetic impurity coupled to two Luttinger liquid leads characterized by the
Luttinger exponent $\alpha(\leq 1)$. We find for resonance conditions, in which
the Fermi energy of the leads is close to a single particle energy of the
impurity, the conductance as a function of temperature is $G \sim \frac{e^2}{h}
(T/T_F)^{2(\alpha-2)}$, whereas for off-resonance conditions the conductance is
$G \sim \frac{e^2}{h} (T/T_F)^{2(\alpha-1)}$. By applying a gate voltage and/or
a magnetic field, one of the spin components can be in resonance while the
other is off-resonance causing a strong asymmetry between the spin-up and
spin-down conductances.",0211447v1
2003-02-24,Effects of a Collective Spin Resonance Mode on the STM Spectra of D-Wave Superconductors,"A high-energy spin resonance mode is known to exist in many high-temperature
superconductors. Motivated by recent scanning tunneling microscopy (STM)
experiments in superconducting Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$, we study the
effects of this resonance mode on the local density of states (LDOS). The
coupling between the electrons in a d-wave superconductor and the resonance
mode produces high-energy peaks in the LDOS, which displays a two-unit-cell
periodic modulation around a nonmagnetic impurity. This suggests a new means to
not only detect the dynamical spin collective mode but also study its coupling
to electronic excitations.",0302494v3
2004-06-01,Quantum interference in resonant tunneling and single spin measurements,"We consider the resonant tunneling through a multi-level system. It is
demonstrated that the resonant current displays quantum interference effects
due to a possibility of tunneling through different levels. We show that the
interference effects are strongly modulated by a relative phase of states
carrying the current. This makes it possible to use these effects for measuring
the phase difference between resonant states in quantum dots. We extend our
model for a description of magnetotransport through the Zeeman doublets. It is
shown that, due to spin-flip transitions, the quantum interference effects
generate a distinct peak in the shot-noise power spectrum at the frequency of
Zeeman splitting. This mechanism explains modulation in the tunneling current
at the Larmor frequency observed in scanning tunneling microscope experiments
and can be utilized for a single spin measurement.",0406010v3
2005-12-24,"Doping Dependence of Bilayer Resonant Spin Excitations in $\bf (Y,Ca)Ba_2Cu_3O_{6+x}$","Resonant magnetic modes with odd and even symmetries were studied by
inelastic neutron scattering experiments in the bilayer high-$T_c$
superconductor $\rm Y_{1-x}Ca_{x}Ba_2Cu_3O_{6+y}$ over a wide doping range. The
threshold of the spin excitation continuum in the superconducting state,
deduced from the energies and spectral weights of both modes, is compared with
the superconducting d-wave gap, measured on the same samples by electronic
Raman scattering in the $B_{1g}$ symmetry. Above a critical doping level of
$\delta \simeq 0.19$, both mode energies and the continuum threshold coincide.
We find a simple scaling relationship between the characteristic energies and
spectral weights of both modes, which indicates that the resonant modes are
bound states in the superconducting energy gap, as predicted by the
spin-exciton model of the resonant mode.",0512634v1
2006-10-03,Tunneling anisotropic magnetoresistance driven by resonant surface states: First-principles calculations of Fe(001) surface,"Fully-relativistic first-principles calculations of the Fe(001) surface
demonstrate that resonant surface (interface) states may produce sizeable
tunneling anisotropic magnetoresistance in magnetic tunnel junctions with a
single magnetic electrode. The effect is driven by the spin-orbit coupling. It
shifts the resonant surface band via the Rashba effect when the magnetization
direction changes. We find that spin-flip scattering at the interface is
controlled not only by the strength of the spin-orbit coupling, but depends
strongly on the intrinsic width of the resonant surface states.",0610061v2
2006-04-11,Effect of Electric and Magnetic Fields on Spin Dynamics in the Resonant Electric Dipole Moment Experiment,"A buildup of the vertical polarization in the resonant electric dipole moment
(EDM) experiment [Y. F. Orlov, W. M. Morse, and Y. K. Semertzidis, Phys. Rev.
Lett. 96, 214802 (2006)] is affected by a horizontal electric field in the
particle rest frame oscillating at a resonant frequency. This field is defined
by the Lorentz transformation of an oscillating longitudinal electric field and
a uniform vertical magnetic one. The effect of a longitudinal electric field is
significant, while the contribution from a magnetic field caused by forced
coherent longitudinal oscillations of particles is dominant. The effect of
electric field on the spin dynamics was not taken into account in previous
calculations. This effect is considerable and leads to decreasing the EDM
effect for the deuteron and increasing it for the proton. The formula for
resonance strengths in the EDM experiment has been derived. The spin dynamics
has been calculated.",0604095v2
2003-09-23,"Single-spin asymmetries of $d(γ,π)NN$ in the first resonance region","Incoherent photoproduction of pions on the deuteron in the first resonance
region is investigated with special emphasis on single-spin asymmetries. For
the elementary pion production operator an effective Lagrangian model which
includes the standard pseudovector Born terms and a resonance contribution from
the $\Delta$(1232)-excitation is used. Single-spin asymmetries, both for
charged and neutral pion photoproduction on the deuteron, are analyzed and
calculated for the first time in the first resonance region. The linear photon
asymmetry $\Sigma$, vector target asymmetry $T_{11}$ and tensor target
asymmetries $T_{20}$, $T_{21}$, and $T_{22}$ for the reaction $d(\gamma,\pi)NN$
are predicted for forthcoming experiments.",0309061v2
2004-08-12,Sub-collision hyperfine structure of nonlinear-optical resonance with field scanning,"Some experimental evidences for methane are produced that the simple
transition from frequency scanning of nonlinear-optical resonances to magnetic
one may be accompanied with transition from sub-Doppler collisionally broadened
structure to sub-collision hyperfine one. It is conditioned by nonlinearity of
splitting of hyperfine sublevel for molecules in the adiabatically varied
magnetic field and respectively breaking the analogy of magnetic and frequency
scannings. The exact calculation of the resonance structure is considered for
molecules with only one spin subsystem. The approximately spin-additive
calculation of the structure is given for sufficiently fast rotating molecules
with greater number of spin subsystems. Within the same approximation an
example of hyperfine doubling in the magnetic and electric spectra of
nonlinear-optical resonance is considered for fluoromethane.",0408052v1
2005-07-05,Stiff spinning torus of electromagnetic two-body motion,"We study an orbit of the electromagnetic two-body problem that involves a
fast (stiff) spinning motion about a circular orbit. We give a multiscale
method of solution that solves for the fast timescale first. The solvability
condition of the asymptotic expansion demands resonances for the fast dynamics.
The stiff resonant tori are found precisely in the atomic magnitude and agree
with many features of the Bohr atom in quantitative and qualitative detail; We
calculate every first emission line of the first 13 observable spectroscopic
series of hydrogen within a few percent deviation. The resonant orbits have
angular momenta that are approximate multiples of Planck's constant and the
emitted frequencies are given by a difference of two linear eigenvalues. This
Lorentz-invariant two-body dynamics exhibts the phenomenon of resonant
dissipation, i.e., the metastable dynamics radiates the center-of-mass energy
while the particles perform fast spinning oscillations of small amplitude about
a circular orbit, a collective radiative recoil.",0507033v3
2008-03-13,Excitation transfer in two two-level systems coupled to an oscillator,"We consider a generalization of the spin-boson model in which two different
two-level systems are coupled to an oscillator, under conditions where the
oscillator energy is much less than the two-level system energies, and where
the oscillator is highly excited. We find that the two-level system transition
energy is shifted, producing a Bloch-Siegert shift in each two-level system
similar to what would be obtained if the other were absent. At resonances
associated with energy exchange between a two-level system and the oscillator,
the level splitting is about the same as would be obtained in the spin-boson
model at a Bloch-Siegert resonance. However, there occur resonances associated
with the transfer of excitation between one two-level system and the other, an
effect not present in the spin-boson model. We use a unitary transformation
leading to a rotated system in which terms responsible for the shift and
splittings can be identified. The level splittings at the anticrossings
associated with both energy exchange and excitation transfer resonances are
accounted for with simple two-state models and degenerate perturbation theory
using operators that appear in the rotated Hamiltonian.",0803.1906v1
2008-09-06,Determination of magnetic order of the rare-earth ions in multiferroic TbMn2O5,"We have employed resonant x-ray magnetic scattering to specifically probe the
magnetic order of the rare-earth ions in multiferroic $\mathrm{TbMn_2O_5}$. Two
energy resonances were observed, one originated from the E1-E1 dipolar
transition and the other from the E2-E2 quadrupolar transition. These
resonances directly probe the valence 5d band and the partially occupied 4f
band, respectively. First, full polarization analysis, which is a measurement
of the scattered polarization as a function of incident polarization, confirmed
a spin polarization of the terbium valence states (probed by the E1-E1
transition) by the $\mathrm{Mn^{4+}}$ spin density in the commensurate phase.
Second, full polarization analysis data were collected in the low-temperature
incommensurate and commensurate phases when tuned to the E2-E2 resonance. By
employing a least-squares fitting procedure, the spin orientations of the
terbium ion sublattice were refined.",0809.1167v1
2009-08-03,Evidence for the existence of Kondo coupled resonant modes in heavy fermions,"Electron Spin Resonance (ESR) can microscopically probe both conduction
electrons (ce) and local moment (LM) spin systems in different materials. A ce
spin resonance (CESR) is observed in metallic systems based on light elements
or with enhanced Pauli susceptibility. LM ESR is frequently seen in compounds
with paramagnetic ions and localized d or f electrons. Here we report a
remarkable and unprecedented ESR signal in the heavy fermion (HF)
superconductor beta-YbAlB4[1] which behaves as a CESR at high temperatures and
acquires characteristics of the Yb3+ LM ESR at low temperature. This dual
behavior in same ESR spectra strikes as an in situ unique observation of the
Kondo quasiparticles giving rise to a new ESR response called Kondo coupled
resonant mode (KCRM). The proximity to a quantum critical point (QCP) may favor
the observation of a KCRM and its dual character in beta-YbAlB4 may unveil the
4f-electrons nature at the QCP.",0908.0044v1
2009-09-10,Resonant and Kondo tunneling through molecular magnets,"Transport through molecular magnets is studied in the regime of strong
coupling to the leads. We consider a resonant-tunneling model where the
electron spin in a quantum dot or molecule is coupled to an additional local,
anisotropic spin via exchange interaction. The two opposite regimes dominated
by resonant tunneling and by Kondo transport, respectively, are considered. In
the resonant-tunneling regime, the stationary state of the impurity spin is
calculated for arbitrarily strong molecule-lead coupling using a
master-equation approach, which treats the exchange interaction perturbatively.
We find that the characteristic fine structure in the differential conductance
persists even if the hybridization energy exceeds thermal energies. Transport
in the Kondo regime is studied within a diagrammatic approach. We show that
magnetic anisotropy gives rise to a splitting of the Kondo peak at low bias
voltages.",0909.1956v2
2009-10-24,Spin-torque driven ferromagnetic resonance in a nonlinear regime,"Spin-valve based nanojunctions incorporating Co|Ni multilayers with
perpendicular anisotropy were used to study spin-torque driven ferromagnetic
resonance (ST-FMR) in a nonlinear regime. Perpendicular field swept resonance
lines were measured under a large amplitude microwave current excitation, which
produces a large angle precession of the Co|Ni layer magnetization. With
increasing rf power the resonance lines broaden and become asymmetric, with
their peak shifting to lower applied field. A nonhysteretic step jump in ST-FMR
voltage signal was also observed at high powers. The results are analyzed in in
terms of the foldover effect of a forced nonlinear oscillator and compared to
macrospin simulations. The ST-FMR nonhysteretic step response may have
applications in frequency and amplitude tunable nanoscale field sensors.",0910.4678v1
2010-03-09,Anisotropic Neutron Spin Resonance in Superconducting BaFe$_{1.9}$Ni$_{0.1}$As$_2$,"We use polarized inelastic neutron scattering to show that the neutron spin
resonance below $T_c$ in superconducting BaFe$_{1.9}$Ni$_{0.1}$As$_2$ ($T_c=20$
K) is purely magnetic in origin. Our analysis further reveals that the
resonance peak near 7~meV only occurs for the planar response. This challenges
the common perception that the spin resonance in the pnictides is an isotropic
triplet excited state of the singlet Cooper pairs, as our results imply that
only the $S_{001}=\pm1$ components of the triplet are involved.",1003.1926v2
2010-08-18,Parameter dependence of resonant spin torque magnetization reversal,"We numerically study ultra fast resonant spin torque (ST) magnetization
reversal in magnetic tunnelling junctions (MTJ) driven by current pulses having
a direct current (DC) and a resonant alternating current (AC) component. The
precessional ST dynamics of the single domain MTJ free layer cell are modelled
in the macro spin approximation. The energy efficiency, reversal time, and
reversal reliability are investigated under variation of pulse parameters like
direct and AC current amplitude, AC frequency and AC phase. We find a range of
AC and direct current amplitudes where robust resonant ST reversal is obtained
with faster switching time and reduced energy consumption per pulse compared to
purely direct current ST reversal. However for a certain range of AC and direct
current amplitudes a strong dependence of the reversal properties on AC
frequency and phase is found. Such regions of unreliable reversal must be
avoided for ST memory applications.",1008.3060v1
2010-09-05,Study of Efimov physics in two nuclear-spin sublevels of 7Li,"Efimov physics in two nuclear-spin sublevels of bosonic lithium is studied
and it is shown that the positions and widths of recombination minima and
Efimov resonances are identical for both states within the experimental errors
which indicates that the short-range physics is nuclear-spin independent. We
also find that the Efimov features are universally related across Feshbach
resonances. These results crucially depend on careful mapping between the
scattering length and the applied magnetic field which we achieve by
characterization of the two broad Feshbach resonances in the different states
by means of rf-spectroscopy of weakly bound molecules. By fitting the binding
energies numerically with a coupled channels calculation we precisely determine
the absolute positions of the Feshbach resonances and the values of the singlet
and triplet scattering lengths.",1009.0926v1
2010-10-29,Spin anisotropy of the resonance in superconducting FeSe0.5Te0.5,"We have used polarized-neutron inelastic scattering to resolve the spin
fluctuations in superconducting FeSe0.5Te0.5 into components parallel and
perpendicular to the layers. A spin resonance at an energy of 6.5 meV is
observed to develop below T_c in both fluctuation components. The resonance
peak is anisotropic, with the in-plane component slightly larger than the
out-of-plane component. Away from the resonance peak the magnetic fluctuations
are isotropic in the energy range studied. The results are consistent with a
dominant singlet pairing state with s^{\pm} symmetry, with a possible minority
component of different symmetry.",1010.6204v2
2012-05-10,Dipolar broadening of nuclear spin resonance under dynamical pumping,"We study the polarisation dependence of the homogeneously broadened nuclear
spin resonance in a crystal. We employ a combinatorial method to restrict the
nuclear states to a fixed polarisation and show that the centre of the
resonance is shifted linearly with the nuclear polarisation by up to the zero
polarisation line width. The width shrinks from its maximum value at zero
polarisation to zero at full polarisation. This suggests to use the line shape
as a direct measure of nuclear polarisation reached under dynamical pumping. In
the limit of single quantum of excitation above the fully ferromagnetic state,
we provide an explicit solution to the problem of nuclear spin dynamics which
links a bound on the fastest decay rate to the observable width of the
resonance line.",1205.2189v1
2012-06-15,Charmed baryon resonances with heavy-quark spin symmetry,"Charmed baryon resonances that are generated dynamically are studied within a
unitary baryon-meson coupled-channel model, which incorporates heavy-quark spin
symmetry. The extension of the SU(3) Weinberg-Tomozawa chiral Lagrangian to
SU(8) spin-flavor symmetry plus a suitable symmetry breaking is used. The model
produces resonances with negative parity from s-wave interaction of
pseudoscalar and vector mesons with $1/2^+$ and $3/2^+$ baryons. Some of our
dynamically generated states can be readily assigned to resonances found
experimentally, while others do not have a straightforward identification and
require the compilation of more data and also refinements of the model.",1206.3444v1
2012-06-23,Scanning tunneling spectroscopy and Dirac point resonances due to a single Co adatom on gated graphene,"Based on the standard tight-binding model of the graphene $\pi$-band
electronic structure, the extended H\""uckel model for the adsorbate and
graphene carbon atoms, and spin splittings estimated from density functional
theory (DFT), the Dirac point resonances due to a single cobalt atom on
graphene are studied. The relaxed geometry of the magnetic adsorbate and the
graphene is calculated using DFT. The system shows strong spin polarization in
the vicinity of the graphene Dirac point energy for all values of the gate
voltage, due to the spin-splitting of Co 3d orbitals. We also model the
differential conductance spectra for this system that have been measured in the
scanning tunneling microscopy (STM) experiments of Brar {\em et al.} [Nat.
Phys. {\bf 7}, 43 (2011)]. We interpret the experimentally observed behavior of
the S-peak in the STM differential conductance spectrum as evidence of
tunneling between the STM tip and a cobalt-induced Dirac point resonant state
of the graphene, via a Co 3d orbital. The cobalt ionization state which is
determined by the energy position of the resonance can be tuned by gate
voltage, similar to that seen in the experiment.",1206.5363v1
2013-03-14,Hybrid Electron Spin Resonance and Whispering Gallery Mode Resonance Spectroscopy of Fe3+ in Sapphire,"The development of a new era of quantum devices requires an understanding of
how paramagnetic dopants or impurity spins behave in crystal hosts. Here, we
describe a new spectroscopic technique which uses traditional Electron Spin
Resonance (ESR) combined with the measurement of a large population of
electromagnetic Whispering Gallery (WG) modes. This allows the characterization
of the physical parameters of paramagnetic impurity ions in the crystal at low
temperatures. We present measurements of two ultra-high purity sapphires cooled
to 20 mK in temperature, and determine the concentration of Fe3+ ions and their
frequency sensitivity to a DC magnetic field. Our method is different to ESR in
that it is possible to track the resonant frequency of the ion from zero
applied magnetic field to any arbitrary value, allowing excellent measurement
precision. This high precision reveals anisotropic behaviour of the Zeeman
splitting, which has not been previously reported. In both crystals, each
Zeeman component demonstrates a different g-factor.",1303.3340v1
2013-04-17,Odd-parity dynamically generated baryon resonances with beauty flavor,"We study baryon resonances with heavy flavor in a molecular approach, thus as
dynamically generated by baryon-meson scattering. This is accomplished by using
a unitary coupled-channel model taking, as bare interaction, the extension of
the Weinberg-Tomozawa SU(3) Lagrangian. A special attention is payed to the
inclusion of heavy-quark spin symmetry and to the study of the generated baryon
resonances that complete the heavy-quark spin multiplets. Our model reproduces
the \Lambda_b(5912) and \Lambda_b(5920) baryons, which were recently observed
by the LHCb collaboration. According to our analysis, these two states are
heavy-quark spin symmetric partners. We also make predictions for few \Xi_b
baryon resonances, which belong to the same SU(3)xHQSS multiplets as the
\Lambda_b particles.",1304.4747v1
2013-08-21,Effective Hamiltonians for quasi-one-dimensional Fermi gases with spin-orbit coupling,"We derive one-dimensional effective Hamiltonians for spin-orbit coupled Fermi
gases confined in quasi-one-dimensional trapping potentials. For energy regime
around the two-body bound state energy, the effective Hamiltonian takes a
two-channel form, where the population in transverse excited levels are
described by dressed molecules in the closed channel. For energy regime
slightly above the continuum threshold, the effective Hamiltonian takes a
single-channel form, where low-energy physics is governed by the
one-dimensional interacting strength determined by three-dimensional scattering
length and transverse confinement. We further discuss the effect of spin-orbit
coupling and effective Zeeman field on the position of confinement-induced
resonances, and show that these resonances can be understood as Feshbach
resonances between the threshold of the transverse ground state and the
two-body bound state associated with the transverse excited states. We expect
that the shift of confinement-induced resonances can be observed under present
experimental technology at attainable temperatures.",1308.4511v1
2013-09-06,Y(4260) and Y(4360) as mixed hadrocharmonium,"Recent BESIII data indicate a significant rate of the process $e^+e^- \to h_c
\pi^+ \pi^-$ at the Y(4260) and Y(4360) resonances, implying a substantial
breaking of the heavy quark spin symmetry. We consider these resonances within
the picture of hadrocharmonium, i.e. of (relatively) compact charmonium
embedded in a light quark mesonic excitation. We suggest that the resonances
Y(4260) and Y(4360) are a mixture, with mixing close to maximal, of two states
of hadrochamonium, one containing a spin-triplet $c \bar c$ pair and the other
containing a spin-singlet heavy quark pair. We argue that this model is in a
reasonable agreement with the available data and produces distinctive and
verifiable predictions for the energy dependence of the production rate in
$e^+e^-$ annihilation of the final states $J/\psi \pi \pi$, $\psi' \pi \pi$ and
$h_c \pi \pi$, including the pattern of interference between the two
resonances.",1309.1681v3
2013-11-22,Specific features of electron spin resonance in quasi-1D magnet β-TeVO4,"The angular and temperature dependences of single crystal ESR spectra at
X-band frequency of quasi 1D spin 1/2 antiferromagnetic zigzag chain system
{\beta}-TeVO4 are reported. Two resonance components in the ESR spectrum have
been detected: a weak narrow resonance on the top of the extremely broad
signal. The narrow line might be due to an impurity, the characteristics of the
broad absorption do not correlate with a picture of the typical behavior for
the V4+ ions (S = 1/2) with a square pyramidal environment. It was found that
at low temperatures the divergence of the spin susceptibility and linewidth of
the observed excitations can be due to a realization of three dimensional
magnetic ordering.",1311.5754v1
2014-01-21,Multiple-Channel Scattering Resonance of One-Dimensional Ultracold Spinor Bosons,"So far the interaction of ultacold atoms can only be tuned within one
particular scattering channel near a resonance, where the spinor structure of
atomic isotopes is destroyed due to the typically large magnetic field. In this
Letter, we propose a scheme to realize {\it multiple-channel scattering
resonance} (MCSR) of ultracold bosons in one-dimension while still keeping
their spinor structure. The MCSR refers to a simultaneous scattering resonance
among all different scattering channels, including those breaking SU(2) and
SO(2) spin rotation symmetries. Essential ingredients for MCSR include the 3D
interactions, the confinement potential and a spin-flipping field. Near MCSR a
many-body spinor system exhibits exotic spin density distributions and pair
correlations, which are significantly different from those near a
single-channel resonance.",1401.5131v2
2014-07-19,Interferometric resonance signatures of Majorana bound states,"We calculate the current noise power spectrum in a nanoscopic interferometer
consisting of a Majorana bound state (MBS) and a localized spin. We show that
for large voltage (though less than the superconducting gap) several strong
resonance peaks appear at frequencies that depend on the Zeeman splitting of
the localized spin and on its tunneling to the localized spin. We also evaluate
the differential conductance and find the unitary limit peak $2e^2/h$ at zero
voltage as well as peaks at voltages corresponding to the resonances. We
propose that detection of the resonances and related peaks in the differential
conductance provide a strong support for the presence of an MBS.",1407.5179v3
2014-11-24,Enhancement of Spin-transfer torque switching via resonant tunneling,"We propose the use of resonant tunneling as a route to enhance the
spin-transfer torque switching characteristics of magnetic tunnel junctions.
The proposed device structure is a resonant tunneling magnetic tunnel junction
based on a MgO-semiconductor heterostructure sandwiched between a fixed magnet
and a free magnet. Using the non-equilibrium Green's function formalism coupled
self consistently with the Landau-Lifshitz-Gilbert-Slonczewski equation, we
demonstrate enhanced tunnel magneto-resistance characteristics as well as lower
switching voltages in comparison with traditional trilayer devices. Two device
designs based on MgO based heterostructures are presented, where the physics of
resonant tunneling leads to an enhanced spin transfer torque thereby reducing
the critical switching voltage by up to 44%. It is envisioned that the
proof-of-concept presented here may lead to practical device designs via
rigorous materials and interface studies.",1411.6454v1
2015-10-12,Resonance-inclined optical nuclear spin polarization of liquids in diamond structures,"Dynamic nuclear polarization (DNP) of molecules in a solution at room
temperature has potential to revolutionize nuclear magnetic resonance
spectroscopy and imaging. The prevalent methods for achieving DNP in solutions
are typically most effective in the regime of small interaction correlation
times between the electron and nuclear spins, limiting the size of accessible
molecules. To solve this limitation, we design a mechanism for DNP in the
liquid phase that is applicable for large interaction correlation times.
Importantly, while this mechanism makes use of a resonance condition similar to
solid-state DNP, the polarization transfer is robust to a relatively large
detuning from the resonance due to molecular motion. We combine this scheme
with optically polarized nitrogen vacancy (NV) center spins in nanodiamonds to
design a setup that employs optical pumping and is therefore not limited by
room temperature electron thermal polarisation. We illustrate numerically the
effectiveness of the model in a flow cell containing nanodiamonds immobilized
in a hydrogel, polarising flowing water molecules 4700-fold above thermal
polarisation in a magnetic field of 0.35 T, in volumes detectable by current
NMR scanners.",1510.03256v1
2015-10-22,Effective resonant stability of Mercury,"Mercury is the unique known planet that is situated in a 3:2 spin-orbit
resonance nowadays. Observations and models converge to the same conclusion:
the planet is presently deeply trapped in the resonance and situated at the
Cassini state $1$, or very close to it. We investigate the complete non-linear
stability of this equilibrium, with respect to several physical parameters, in
the framework of Birkhoff normal form and Nekhoroshev stability theory. We use
the same approach adopted for the 1:1 spin-orbit case with a peculiar attention
to the role of Mercury's non negligible eccentricity. The selected parameters
are the polar moment of inertia, the Mercury's inclination and eccentricity and
the precession rates of the perihelion and node. Our study produces a bound to
both the latitudinal and longitudinal librations (of 0.1 radians) for a long
but finite time (greatly exceeding the age of the solar system). This is the
so-called effective stability time. Our conclusion is that Mercury, placed
inside the 3:2 spin-orbit resonance, occupies a very stable position in the
space of these physical parameters, but not the most stable possible one.",1510.06543v1
2015-10-30,On the rotation of co-orbital bodies in eccentric orbits,"We investigate the resonant rotation of co-orbital bodies in eccentric and
planar orbits. We develop a simple analytical model to study the impact of the
eccentricity and orbital perturbations on the spin dynamics. This model is
relevant in the entire domain of horseshoe and tadpole orbit, for moderate
eccentricities. We show that there are three different families of spin-orbit
resonances, one depending on the eccentricity, one depending on the orbital
libration frequency, and another depending on the pericenter's dynamics. We can
estimate the width and the location of the different resonant islands in the
phase space, predicting which are the more likely to capture the spin of the
rotating body. In some regions of the phase space the resonant islands may
overlap, giving rise to chaotic rotation.",1510.09165v2
2015-12-07,Angular dependent micro-ESR characterization of a locally doped Gd3+:Al2O3 system,"Interfacing rare-earth doped crystals with superconducting circuit
architectures provides an attractive platform for quantum memory and transducer
devices. Here we present the detailed characterization of such a hybrid system:
a locally implanted rare-earth Gd$^{3+}$ in Al$_2$O$_3$ spin system coupled to
a superconducting micro-resonator.
  We investigate the properties of the implanted spin system through angular
dependent micro-resonator electron spin resonance (micro-ESR) spectroscopy. We
find, despite the high energy near-surface implantation, the resulting
micro-ESR spectra to be in excellent agreement with the modelled Hamiltonian,
supporting the integration of dopant ions into their relevant lattice sites
whilst maintaining crystalline symmetries. Furthermore, we observe clear
contributions from individual microwave field components of our
micro-resonator, emphasising the need for controllable local implantation.",1512.02270v1
2016-06-07,Resonant Raman scattering theory for Kitaev models and their Majorana fermion boundary modes,"We study the inelastic light scattering response in two- (2D) and
three-dimensional (3D) Kitaev spin-liquid models with \ms band structures in
the symmetry classes BDI and D leading to protected gapless surface modes. We
present a detailed calculation of the resonant Raman/Brillouin scattering
vertex relevant to iridate and ruthenate compounds whose low-energy physics is
believed to be proximate to these spin-liquid phases. In the symmetry class
BDI, we find that while the resonant scattering on thin films can detect the
gapless boundary modes of spin liquids, the non-resonant processes do not
couple to them. For the symmetry class D, however, we find that the coupling
between both types of light-scattering processes and the low-energy surface
states is strongly suppressed. Additionally, we describe the effect of weak
time-reversal symmetry breaking perturbations on the bulk Raman response of
these systems.",1606.02189v1
2016-10-14,Magnetic resonances of multiferroic TbFe$_3$(BO$_3$)$_4$,"Low-energy magnetic excitations of the easy-axis antiferromagnet
TbFe$_3$(BO$_3$)$_4$ are investigated by far-infrared absorption and reflection
spectroscopy in high magnetic fields up to 30 T. The observed field dependence
of the resonance frequencies and the magnetization are reproduced by a
mean-field spin model for magnetic fields applied both along and perpendicular
to the easy axis. Based on this model we determined the full set of magnetic
interactions, including Fe-Fe and Fe-Tb exchange interactions, single-ion
anisotropy for Tb ions and $g$-factors, which describe the ground-state spin
texture and the low-energy spin excitations of TbFe$_3$(BO$_3$)$_4$. Compared
to earlier studies we allow a small canting of the nearly Ising-like Tb moments
to achieve a quantitative agreement with the magnetic susceptibility
measurements. The additional high energy magnetic resonance lines observed,
besides the two resonances expected for a two-sublattice antiferromagnet,
suggest a more complex six-sublattice magnetic ground state for
TbFe$_3$(BO$_3$)$_4$.",1610.04455v1
2018-03-28,Advanced Optimal Control Methods for Spin Systems,"Work within this thesis advances optimal control algorithms for application
to magnetic resonance systems. Specifically, presenting a quadratically
convergent version of the gradient ascent pulse engineering method. The work is
formulated in a superoperator representation of the Liouville-von Neumann
equation.
  A Newton-grape method is developed using efficient calculation of analytical
second directional derivatives. The method is developed to scale with the same
complexity as methods that use only first directional derivatives.
  Algorithms to ensure a well-conditioned and positive definite matrix of
second directional derivatives are used so the sufficient conditions of
gradient-based numerical optimisation are met.
  A number of applications of optimal control in magnetic resonance are
investigated: solid-state nuclear magnetic resonance, magnetisation-to-singlet
pulses, and electron spin resonance experiments.",1803.10432v3
2018-05-10,Broadband optomechanical transduction of nanomagnetic spin modes,"The stable vortex state that occurs in micron-scale magnetic disks is one of
the most interesting and potentially useful phenomenon in nanomagnetism. A
variety of tools have been applied to study the vortex state, and collective
spin excitations corresponding to harmonic motion of the vortex, but to-date
these tools have measured either strongly driven vortex resonances or have been
unable to simultaneously measure static properties such as the magnetization.
Here we show that by combining the sensitivity of cavity optomechanics with the
technique of torque mixing resonance spectroscopy, we are able to measure the
magnetization, in-plane susceptibility, and spin resonances of individual
vortices in the low-drive limit. These measurements elucidate the complex
behavior of the vortex as it moves through the pinning landscape of the disk.
Furthermore, we observe gyrotropic resonances as high as 1.1 GHz, suggesting
the use of engineering defects for applications such as microwave-to-optical
wavelength conversion.",1805.04186v1
2018-11-11,Reconstruction of the DOS at the end of a S/F bilayer,"Influence of a nonmagnetic surface on the density of states in a spin-split
superconductor, which is realized on the basis of a S/F bilayer, is
investigated. It is demonstrated that if the ferromagnet magnetization has a
defect in the form of a domain wall in the vicinity of the surface, the
superconducting density of states is reconstructed manifesting the spin-split
Andreev resonances. Formation of these resonances is not connected to any
superconducting order parameter inhomogeneities. Andreev reflection processes
forming the resonances occur at the inhomogeneity of the spin-split gap
generated by the domain wall. These resonances can be used as a spectroscopic
probe of a domain wall presence and motion.",1811.04373v2
2018-10-09,Tunable amplification and cooling of a diamond resonator with a microscope,"Controlling the dynamics of mechanical resonators is central to many quantum
science and metrology applications. Optomechanical control of diamond
resonators is attractive owing to diamond's excellent physical properties and
its ability to host electronic spins that can be coherently coupled to
mechanical motion. Using a confocal microscope, we demonstrate tunable
amplification and damping of a diamond nanomechanical resonator's motion.
Observation of both normal mode cooling from room temperature to 80K, and
amplification into self--oscillations with $60\,\mu\text{W}$ of optical power
is observed via waveguide optomechanical readout. This system is promising for
quantum spin-optomechanics, as it is predicted to enable optical control of
stress-spin coupling with rates of $\sim$ 1 MHz (100 THz) to ground (excited)
states of diamond nitrogen vacancy centers.",1810.04196v2
2018-10-27,Microwave control of thermal magnon spin transport,"We observe that an rf microwave field strongly influences the transport of
incoherent thermal magnons in yttrium iron garnet. Ferromagnetic resonance in
the nonlinear regime suppresses thermal magnon transport by 95%. The transport
is also modulated at non-resonant conditions in two cases, both related to the
magnon band minimum. Firstly, a strong enhancement of the nonlocal signal
appears at a static magnetic field below the resonance condition. This increase
only occurs at one field polarity and can be as large as 800%. We attribute
this effect to magnon kinetic processes, which give rise to band-minimum
magnons and high-energy chiral surface modes. Secondly, the signal increases at
a static field above the resonance condition, where the rf frequency coincides
with the magnon band minimum. Our study gives insight into the interplay
between coherent and incoherent spin dynamics: The rf field modifies the
occupation of relevant magnon states and, via kinetic processes, the magnon
spin transport.",1810.11667v1
2019-08-21,Skyrme Functional with Tensor Terms from ab initio Calculations: Results for the Spin-Orbit Splittings,"A new Skyrme functional including tensor terms is presented. The tensor terms
have been determined by fitting the results of relativistic
Brueckner-Hartree-Fock (RBHF) studies on neutron-proton drops. Unlike all
previous studies, where the tensor terms were usually determined by fitting to
experimental data of single-particle levels, the pseudodata calculated by RBHF
does not contain beyond mean-field effect such as the particle-vibration
coupling and, therefore, can provide information on the tensor term without
ambiguities. The obtained new functional, named SAMi-T, can describe well
ground-state properties such as binding energies, radii, spin-orbit splittings
and, at the same time, the excited state properties such as those of the Giant
Monopole Resonance (GMR), Giant Dipole Resonance (GDR), Gamow-Teller Resonance
(GTR), and Spin-Dipole Resonance (SDR).",1908.08090v1
2019-09-18,Ferromagnetic resonance with magnetic phase selectivity by means of resonant elastic x-ray scattering on a chiral magnet,"Cubic chiral magnets, such as Cu$_{2}$OSeO$_{3}$, exhibit a variety of
non-collinear spin textures, including a trigonal lattice of spin whirls,
so-called skyrmions. Using magnetic resonant elastic x-ray scattering (REXS) on
a crystalline Bragg peak and its magnetic satellites while exciting the sample
with magnetic fields at GHz frequencies, we probe the ferromagnetic resonance
modes of these spin textures by means of the scattered intensity. Most notably,
the three eigenmodes of the skyrmion lattice are detected with large
sensitivity. As this novel technique, which we label REXS-FMR, is carried out
at distinct positions in reciprocal space, it allows to distinguish
contributions originating from different magnetic states, providing information
on the precise character, weight and mode mixing as a prerequisite of tailored
excitations for applications.",1909.08293v2
2020-02-19,Single DNA Electron Spin Resonance Spectroscopy in Aqueous Solutions,"Magnetic resonance spectroscopy of single biomolecules under
near-physiological conditions may substantially advance understanding of
biological function, yet remains very challenging. Here we use nitrogen-vacancy
centers in diamonds to detect electron spin resonance spectra of individual,
tethered DNA duplexes labeled with a nitroxide spin label in aqueous buffer
solutions at ambient temperatures. This paves the way for magnetic resonance
studies on single biomolecules and their inter-molecular interactions in a
native-like environment.",2002.08425v1
2020-02-20,Optical Magnetometer: Quantum Resonances at pumping repetition rate of 1/n of the Larmor frequency,"The response of a SERF atomic magnetometer to a repetitive short-pulsed pump
was investigated. Quantum sub-resonances at a repetition rate of $1/n$ of the
Larmor frequency of the magnetic field inside the shield are experimentally
observed and theoretically explained. This is a type of synchronization
phenomenon. Investigations in single alkali atoms cells as well as mixed alkali
atoms of K and Rb are presented. In the later, one species is pumped while the
probe is on the other specie polarized by spin exchange. The effect of spin
destruction, spin exchange and collisions are studied in order to account for
the width of the resonances. Quantum calculations of a three levels $\Lambda$
model for this phenomenon exhibit a dip at the resonance frequency in the
absorption spectrum for both cases of pulsed and CW pump modes and an evidence
for EIT.",2002.08631v4
2020-10-08,Oscillatory magnetic fields for neutron resonance spin-echo spectroscopy,"The generation of high frequency oscillatory magnetic fields represents a
fundamental component underlying the successful implementation of neutron
resonant spin-echo spectrometers, a class of instrumentation critical for the
high-resolution extraction of dynamical excitations (structural and magnetic)
in materials. In this paper, the setup of the resonant circuits at the
longitudinal resonant spin-echo spectrometer RESEDA is described in
comprehensive technical detail. We demonstrate that these circuits are capable
of functioning at frequencies up to 3.6 MHz and over a broad bandwidth down to
35 kHz using a combination of signal generators, amplifiers, impedance matching
transformers, and a carefully designed cascade of tunable capacitors and
customized coils.",2010.04161v2
2020-12-04,Nutation in antiferromagnetic resonance,"The effect of inertial spin dynamics is compared between ferromagnetic,
antiferromagnetic and ferrimagnetic systems. The linear response to an
oscillating external magnetic field is calculated within the framework of the
inertial Landau--Lifshitz--Gilbert equation using analytical theory and
computer simulations. Precession and nutation resonance peaks are identified,
and it is demonstrated that the precession frequencies are reduced by the spin
inertia, while the lifetime of the excitations is enhanced. The interplay
between precession and nutation is found to be the most prominent in
antiferromagnets, where the timescale of the exchange-driven sublattice
dynamics is comparable to inertial relaxation times. Consequently,
antiferromagnetic resonance techniques should be better suited for the search
for intrinsical inertial spin dynamics on ultrafast timescales than
ferromagnetic resonance.",2012.02790v3
2023-03-01,"Proton \textit{s}-resonance states of $^{12}$C and $^{14,15}$O within the Skyrme Hartree-Fock mean-field framework","The excitation functions of proton elastic scattering on $^{12}$C and
$^{14,15}$O nuclei at the energies near the proton-emission threshold are
calculated using the Skyrme Hartree-Fock (SHF) in continuum approach. For each
excitation function, the first resonance is identified as the $s$-state
resonance of the mean-field theory. For $^{15}$O, whose ground-state spin is
nonzero, the $s$-state resonance splits into two resonances via the spin-spin
component of the optical potential. With a slight adjustment of the strength of
central potential, which is obtained from the SHF in continuum approach, the
excitation functions of proton elastic scattering for the three nuclei can be
explained with high accuracy. The proposed framework can provide a practical
method to explain nuclear scattering at the energies near the proton-emission
threshold with minimal experimental input.",2303.00472v1
2023-03-23,New Resonances of Supernova Neutrinos in Twisting Magnetic Fields,"We investigate the effect of resonant spin conversion of the neutrinos
induced by the geometrical phase in a twisting magnetic field. We find that the
geometrical phase originating from the rotation of the transverse magnetic
field along the neutrino trajectory can trigger a new resonant spin conversion
of Dirac neutrinos inside the supernova, even if there were no such transitions
in the fixed-direction field case. We have shown that even though resonant spin
conversion is too weak to affect solar neutrinos, it could have a remarkable
consequence on supernova neutronization bursts where very intense magnetic
fields are quite likely. We demonstrate how the flavor composition at Earth can
be used as a probe to establish the presence of non-negligible magnetic
moments, potentially down to $10^{-15}~\mu_B$ in upcoming neutrino experiments
like the Deep Underground Neutrino Experiment (DUNE), and the Hyper-Kamiokande
(HK). Possible implications are analyzed.",2303.13572v2
2023-06-21,Spin Partners of the $B^{(*)}\bar{B}^{(*)}$ resonances with a different approach than the Breit-Wigner parameterization,"In general, resonances are obtained by the Breit-Wigner parameterization.
However, it is not entirely appropriate to use this parameterization with
near-threshold resonances such as the $Z_b(10610)$ and the $Z_b(10650)$, as
Breit-Wigner does not contain the threshold effect. To eliminate this defect, a
recently proposed alternative distribution, the Sill, is used to predict
possible heavy quark spin symmetry partners of the $Z_b(10610)$ and the
$Z_b(10650)$. With the Sill values of the $Z_b(10650)$ and the $Z_b(10610)$
states, assuming these exotics generate molecular states consisting of contact
and a pion exchange potential, heavy quark spin symmetry partners are examined
with $S$ and $D$-wave contributions. In the light of the Sill type resonance
approach, all the partners are found as bound states.",2306.12403v1
2023-08-03,Bichromatic Rabi control of semiconductor qubits,"Electrically-driven spin resonance is a powerful technique for controlling
semiconductor spin qubits. However, it faces challenges in qubit addressability
and off-resonance driving in larger systems. We demonstrate coherent
bichromatic Rabi control of quantum dot hole spin qubits, offering a
spatially-selective approach for large qubit arrays. By applying simultaneous
microwave bursts to different gate electrodes, we observe multichromatic
resonance lines and resonance anticrossings that are caused by the ac Stark
shift. Our theoretical framework aligns with experimental data, highlighting
interdot motion as the dominant mechanism for bichromatic driving.",2308.01720v1
2023-09-16,Spin dependence in the $p$-wave resonance of ${^{139}\vec{\rm{La}}+\vec{n}}$,"We measured the spin dependence in a neutron-induced $p$-wave resonance by
using a polarized epithermal neutron beam and a polarized nuclear target. Our
study focuses on the 0.75~eV $p$-wave resonance state of $^{139}$La+$n$, where
largely enhanced parity violation has been observed. We determined the partial
neutron width of the $p$-wave resonance by measuring the spin dependence of the
neutron absorption cross section between polarized $^{139}\rm{La}$ and
polarized neutrons. Our findings serve as a foundation for the quantitative
study of the enhancement effect of the discrete symmetry violations caused by
mixing between partial amplitudes in the compound nuclei.",2309.08905v1
2023-12-17,Hadronic decay of exotic mesons consisting of four charm quarks,"In 2020, a di-$J/\psi$ resonance centered at around 6.9 $\mathrm{GeV}$ was
discovered by the LHCb Collaboration, and was later confirmed by the ATLAS and
CMS Collaborations. In addition to the 6.9-$\mathrm{GeV}$ resonance, its low
energy counterpart centered at around 6552 $\mathrm{MeV}$ was also observed by
the CMS Collaboration. In this paper, we calculate the inclusive decay width of
such exotic mesons into light hadrons and into open charms, respectively,
assuming them as either genuine tetraquarks or molecules composed of two
$J/\psi$'s. Since the spins of these resonances have not yet been
experimentally measured, regarding them as S-wave bound states, we consider all
possible spin configurations, namely spin-0 and spin-2, that decay exclusively
into double $J/\psi$, and find that the ratio ($\mathcal{R}$) of the decay
width for the light-hadron final states to that for the charmed final states
differs significantly among different spin configurations, which can help to
explore the nature of the observed di-$J/\psi$ resonances and fix the mixing
angle for the $J^{PC}=0^{++}$ tetraquark.",2312.10850v1
1996-10-21,Geometro-Stochastically Quantized Fields with Internal Spin Variables,"The use of internal variables for the description of relativistic particles
with arbitrary mass and spin in terms of scalar functions is reviewed and
applied to the stochastic phase space formulation of quantum mechanics.
Following Bacry and Kihlberg a four-dimensional internal spin space $\bar S$ is
chosen possessing an invariant measure and being able to represent integer as
well as half integer spins. $\bar S$ is a homogeneous space of the group $SL(2,
C)$ parametrized in terms of spinors $\a\in C_2$ and their complex conjugates
$\bar\a$. The generalized scalar quantum mechanical wave functions may be
reduced to yield irreducible components of definite physical mass and spin
$[m,s]$, with $m\ge 0$ and $s=0, 1/2, 1, 3/2 ...$, with spin described in terms
of the usual $(2s+1)$-component fields. Viewed from the internal space
description of spin this reduction amounts to a restriction of the variable
$\a$ to a compact subspace of $\bar S$, i.e. a ``spin shell'' $S^2_{r=2s}$ of
radius $r=2s$ in $ C_2$. This formulation of single particles or single
antiparticles of type $[m,s]$ is then used to study the geometro- stochastic
(i.e. quantum) propagation of amplitudes for arbitrary spin on a curved
background space-time possessing a metric and axial vector torsion treated as
external fields. A Poincar\'e gauge covariant path integral-like representation
for the probability amplitude (generalized wave function) of a particle with
arbitrary spin is derived satisfying a second order wave equation on the
Hilbert bundle constructed over curved space-time. The implications for the
stochastic nature of polarization effects in the presence of gravitation are
pointed out and the extension to Fock bundles of bosonic and fermionic type is
briefly mentioned.",9610046v1
2012-10-24,An effectual template bank for the detection of gravitational waves from inspiralling compact binaries with generic spins,"We report the construction of a three-dimensional template bank for the
search for gravitational waves from inspiralling binaries consisting of
spinning compact objects. The parameter space consists of two dimensions
describing the mass parameters and one ""reduced-spin"" parameter, which
describes the secular (non-precessing) spin effects in the waveform. The
template placement is based on an efficient stochastic algorithm and makes use
of the semi-analytical computation of a metric in the parameter space. We
demonstrate that for ""low-mass"" ($m_1 + m_2 \lesssim 12\,M_\odot$) binaries,
this template bank achieves effective fitting factors $\sim0.92$--$0.99$
towards signals from generic spinning binaries in the advanced detector era
over the entire parameter space of interest (including binary neutron stars,
binary black holes, and black hole-neutron star binaries). This provides a
powerful and viable method for searching for gravitational waves from generic
spinning low-mass compact binaries. Under the assumption that spin magnitudes
of black-holes [neutron-stars] are uniformly distributed between 0--0.98 [0 --
0.4] and spin angles are isotropically distributed, the expected improvement in
the average detection volume (at a fixed signal-to-noise-ratio threshold) of a
search using this reduced-spin bank is $\sim20-52\%$, as compared to a search
using a non-spinning bank.",1210.6666v2
2021-10-26,Understanding how fast black holes spin by analysing data from the second gravitational-wave catalogue,"The Advanced LIGO and Virgo detectors have now observed approximately 50
black-hole-binary mergers, from which we can begin to infer how rapidly
astrophysical black holes spin. The LIGO-Virgo Collaboration (LVC) analysis of
detections up to the end of the first half of the third observing run (O3a)
appeared to uncover a distribution of spin magnitudes that peaks at $\sim$0.2.
This is surprising: is there a black-hole formation mechanism that prefers a
particular, non-zero spin magnitude, or could this be the cumulative effect of
multiple formation processes? We perform an independent analysis of the most
recent gravitational-wave catalogue, and find that (a) the support for the LVC
spin-magnitude is tenuous; in particular, adding or removing just one signal
from the catalogue can remove the statistical preference for this distribution,
and (b) we find potential evidence for two spin sub-populations in the observed
black holes; one with extremely low spins and one with larger spin magnitudes.
We make the connection that these spin sub-populations could be correlated with
the mass of the binary, with more massive binaries preferring larger spin
magnitudes, and argue that this may provide evidence for hierarchical mergers
in the second gravitational-wave catalogue.",2110.13542v2
2017-03-20,Hierarchical analysis of gravitational-wave measurements of binary black hole spin-orbit misalignments,"Binary black holes may form both through isolated binary evolution and
through dynamical interactions in dense stellar environments. The formation
channel leaves an imprint on the alignment between the black hole spins and the
orbital angular momentum. Gravitational waves from these systems directly
encode information about the spin--orbit misalignment angles, allowing them to
be (weakly) constrained. Identifying sub-populations of spinning binary black
holes will inform us about compact binary formation and evolution. We simulate
a mixed population of binary black holes with spin--orbit misalignments
modelled under a range of assumptions. We then develop a hierarchical analysis
and apply it to mock gravitational-wave observations of these populations.
Assuming a population with dimensionless spin magnitudes of $\chi = 0.7$, we
show that tens of observations will make it possible to distinguish the
presence of subpopulations of coalescing binary black holes based on their spin
orientations. With $100$ observations it will be possible to infer the relative
fraction of coalescing binary black holes with isotropic spin directions
(corresponding to dynamical formation in our models) with a fractional
uncertainty of $\sim 40\%$. Meanwhile, only $\sim 5$ observations are
sufficient to distinguish between extreme models---all binary black holes
either having exactly aligned spins or isotropic spin directions.",1703.06873v2
2021-11-26,The effect of spin mismodeling on gravitational-wave measurements of the binary neutron star mass distribution,"The binary neutron star (BNS) mass distribution measured with
gravitational-wave observations has the potential to reveal information about
the dense matter equation of state, supernova physics, the expansion rate of
the universe, and tests of General Relativity. As most current
gravitational-wave analyses measuring the BNS mass distribution do not
simultaneously fit the spin distribution, the implied population-level spin
distribution is the same as the spin prior applied when analyzing individual
sources. In this work, we demonstrate that introducing a mismatch between the
implied and true BNS spin distributions can lead to biases in the inferred mass
distribution. This is due to the strong correlations between the measurements
of the mass ratio and spin components aligned with the orbital angular momentum
for individual sources. We find that applying a low-spin prior which excludes
the true spin magnitudes of some sources in the population leads to
significantly overestimating the maximum neutron star mass and underestimating
the minimum neutron star mass at the population level with as few as six BNS
detections. The safest choice of spin prior that does not lead to biases in the
inferred mass distribution is one which allows for high spin magnitudes and
tilts misaligned with the orbital angular momentum.",2111.13619v2
2022-06-22,Probing Laser-Induced Spin-Current Generation in Synthetic Ferrimagnets Using Spin Waves,"Several rare-earth transition-metal ferrimagnetic systems exhibit all-optical
magnetization switching upon excitation with a femtosecond laser pulse.
Although this phenomenon is very promising for future opto-magnetic data
storage applications, the role of non-local spin transport in these systems is
scarcely understood. Using Co/Gd and Co/Tb bilayers we isolate the contribution
of the rare-earth materials to the generated spin currents by using the
precessional dynamics they excite in an adjacent ferromagnetic layer as a
probe. By measuring THz standing spin-waves as well as GHz homogeneous
precessional modes, we probe both the high- and low-frequency components of
these spin currents. The low-frequency homogeneous mode indicates a significant
contribution of Gd to the spin current, but not from Tb, consistent with the
difficulty in achieving all-optical switching in Tb-containing systems.
Measurements on the THz frequency spin waves reveal the inability of the
rare-earth generated spin currents to excite dynamics at the sub-ps timescale.
We present modelling efforts using the $s$-$d$ model, which effectively
reproduce our results and allow us to explain the behavior in terms of the
temporal profile of the spin current.",2206.10934v1
2023-10-06,Effective-One-Body Numerical-Relativity waveform model for Eccentric spin-precessing binary black hole coalescence,"Waveform models are important to gravitational wave data analysis. People
recently pay much attention to the waveform model construction for eccentric
binary black hole coalescence. Several Effective-One-Body Numerical-Relativity
waveform models of eccentric binary black hole coalescence have been
constructed. But none of them can treat orbit eccentricity and spin-precessing
simultaneously. The current paper focuses on this problem. The authors
previously have constructed waveform model for spin-aligned eccentric binary
black hole coalescence $\texttt{SEOBNRE}$. Here we extend such waveform model
to describe eccentric spin-precessing binary black hole coalescence. We
calculate the 2PN orbital radiation-reaction forces and the instantaneous part
of the decomposed waveform for a general spinning precessing binary black hole
system in effective-one-body (EOB) coordinates. We implement these results
based on our previous $\texttt{SEOBNRE}$ waveform model. We have also compared
our model waveforms to both SXS and RIT numerical relativity waveforms. We find
good consistency between our model and numerical relativity. Based on our new
waveform model, we analyze the impact of the non-perpendicular spin
contributions on waveform accuracy. We find that the non-perpendicular spin
contributions primarily affect the phase of the gravitational waveforms. For
the current gravitational wave detectors, this contribution is not significant.
The future detectors may be affected by such non perpendicular spin
contributions. More importantly our $\texttt{SEOBNRE}$ waveform model, as the
first theoretical waveform model to describe eccentric spin-precessing binary
black hole coalescence, can help people to analyze orbit eccentricity and spin
precession simultaneously for gravitational wave detection data.",2310.04552v1
2002-08-08,Stability of Rossby waves in the beta-plane approximation,"Floquet theory is used to describe the unstable spectrum at large scales of
the beta-plane equation linearized about Rossby waves. Base flows consisting of
one to three Rossby wave are considered analytically using continued fractions
and the method of multiple scales, while base flow with more than three Rossby
waves are studied numerically. It is demonstrated that the mechanism for
instability changes from inflectional to triad resonance at an O(1) transition
Rhines number Rh, independent of the Reynolds number. For a single Rossby wave
base flow, the critical Reynolds number Re^c for instability is found in
various limits. In the limits Rh --> infinity and k --> 0, the classical value
Re^c = sqrt(2) is recovered. For Rh --> 0 and all orientations of the Rossby
wave except zonal and meridional, the base flow is unstable for all Reynolds
numbers; a zonal Rossby wave is stable, while a meridional Rossby wave has
critical Reynolds number Re^c = sqrt(2). For more isotropic base flows
consisting of many Rossby waves (up to forty), the most unstable mode is purely
zonal for 2 <= Rh < infinity and is nearly zonal for Rh = 1/2, where the
transition Rhines number is again O(1), independent of the Reynolds number and
consistent with a change in the mechanism for instability from inflectional to
triad resonance.",0208032v1
2014-10-15,A comparison of weak-turbulence and PIC simulations of weak electron-beam plasma interaction,"Quasilinear theory has long been used to treat the problem of a weak electron
beam interacting with plasma and generating Langmuir waves. Its extension to
weak-turbulence theory treats resonant interactions of these Langmuir waves
with other plasma wave modes, in particular ion-sound waves. These are strongly
damped in plasma of equal ion and electron temperatures, as sometimes seen in,
for example, the solar corona and wind. Weak turbulence theory is derived in
the weak damping limit, with a term describing ion-sound wave damping then
added. In this paper we use the EPOCH particle-in-cell code to numerically test
weak turbulence theory for a range of electron-ion temperature ratios. We find
that in the cold ion limit the results agree well, but increasing ion
temperature the three-wave resonance becomes broadened in proportion to the
ion-sound wave damping rate. This may be important in, for example, the theory
of solar radio bursts, where the spectrum of Langmuir waves is critical.
Additionally we establish lower limits on the number of simulation particles
needed to accurately reproduce the electron and wave distributions in their
saturated states, and to reproduce their intermediate states and time
evolution.",1410.4046v2
2015-12-03,Magnetospheric ULF waves driven by external sources,"The multi-spacecraft missions (Cluster and THEMIS) observations allowed to
collect large data base for Ultra Low Frequency (ULF) waves properties, their
localization, and sources. Mainly here we focused on these recent results.
Studying of the source and characteristics of ULF waves can help in the
understanding of the interaction and energy transport from solar wind to the
magnetosphere. Here we present peculiarities of ULF waves generated by
different solar wind phenomenon: surface magnetopause instability,
magnetosphere cavity modes and solar wind dynamic pressure sudden impulses (SI)
penetration into the magnetosphere. Permanent observations of ULF waves involve
existence of the permanent source and, as the previous studies showed, the
contributions to Pc4-Pc5 ULF wave power from the external sources are larger
than the contribution from internal magnetosphere sources. The Kelvin-Helmholtz
instability (KHI) can generate on the magnetosphere flanks classical ULF
resonant waves with spatially localized amplitude maximum. As observations show
the constraint satisfaction of KHI development is quite rare. SI in solar wind
dynamic pressure generate ULF waves with different polarization and frequency
close to the frequency of the local field line resonance (FLR). Wide range of
temporal and amplitude characteristics of solar wind dynamics can generate
magnetosphere cavity modes and magnetosonic perturbations which penetrate
through the magnetosphere and can couple with the local FLR modes. The observed
dependence of ULF waves properties on their localization are well correspond to
these sources and their occurrence.",1512.00919v1
2018-06-04,Density Waves and the Viscous Overstability in Saturn's Rings,"This paper addresses resonantly forced spiral density waves in a dense
planetary ring which is close to the threshold for viscous overstability. We
solve numerically the hydrodynamical equations for a dense, axisymmetric thin
disk in the vicinity of an inner Lindblad resonance with a perturbing
satellite. The spiral shape of a density wave is taken into account through a
suitable approximation of the advective terms arising from the fluid orbital
motion. This paper is a first attempt to model the co-existence of resonantly
forced density waves and short-scale axisymmetric overstable wavetrains in
Saturn's rings by conducting large-scale hydrodynamical integrations. These
integrations reveal that the two wave types undergo complex interactions, not
taken into account in existing models for the damping of density waves. In
particular it is found that, depending on the relative magnitude of both wave
types, the presence of viscous overstability can lead to a damping of an
unstable density wave and vice versa. The damping of viscous overstability by a
density wave is investigated further by employing a simplified model of an
axisymmetric ring perturbed by a nearby Lindblad resonance. A linear
hydrodynamic stability analysis as well as local N-body simulations of this
model system are performed and support the results of our large-scale
hydrodynamical integrations.",1806.01211v3
2019-01-15,On the normal form of synchronization and resonance between vorticity waves in shear flow instability,"A central mechanism of linearised two dimensional shear instability can be
described in terms of a nonlinear, action-at-a-distance, phase-locking
resonance between two vorticity waves which propagate counter to their local
mean flow as well as counter to each other. Here we analyze the prototype of
this interaction as an autonomous, nonlinear dynamical system. The wave
interaction equations can be written in a generalized Hamiltonian action-angle
form. The pseudo-energy serves as the Hamiltonian of the system, the action
coordinates are the contribution of the vorticity waves to the wave-action, and
the angles are the phases of the vorticity waves. The term ""generalized
action-angle"" emphasizes that the action of each wave is generally time
dependent, which allows instability. The synchronization mechanism between the
wave phases depends on the cosine of their relative phase, rather than the sine
as in the Kuramoto model. The unstable normal modes of the linearised dynamics
correspond to the stable fixed points of the dynamical system and vice versa.
Furthermore, the normal form of the wave interaction dynamics reveals a new
type of inhomogeneous bifurcation -- annihilation of a pair of stable and
unstable fixed points yields the emergence of two neutral center fixed points
of opposite circulation.",1901.04905v2
2006-10-10,Frequency Evolution of the Gravitational Waves for Compact Binaries,"We present here a complete list of contributions to the gravitational wave
frequency evolution from compact binaries on circular orbits up to the second
post-Newtonian order by including the interaction of magnetic dipole moments,
quadrupole-monopole interactions together with the spin-orbit, the spin-spin
and the self-interaction spin contributions. We apply our results to the
Manchester et al. model of the J0737-3039A-B double pulsar.",0610290v1
1995-03-09,Spin Dynamics of the Triangular Heisenberg Antiferromagnet: A Schwinger Boson Approach,"We have analyzed the two-dimensional antiferromagnetic Heisenberg model on
the triangular lattice using a Schwinger boson mean-field theory. By expanding
around a state with local $120^\circ$ order, we obtain, in the limit of
infinite spin, results for the excitation spectrum in complete agreement with
linear spin wave theory (LSWT). In contrast to LSWT, however, the modes at the
ordering wave vectors acquire a mass for finite spin. We discuss the origin of
this effect.",9503048v1
1996-02-05,Spin Excitation Spectrum of La$_{1-x}A_x$MnO$_3$,"As an effective model to describe perovskite-type manganates (La,$A$)MnO$_3$,
the double-exchange model on a cubic lattice is investigated. Spin excitation
spectrum of the model in the ground state is studied using the spin wave
approximation. Spin wave dispersion relation observed in the inelastic neutron
scattering experiment of La$_{0.7}$Pb$_{0.3}$MnO$_3$ is reproduced. Effective
values for the electron bandwidth as well as Hund's coupling is estimated from
the data.",9602017v1
1996-04-23,Dynamics of coupled quantum spin chains,"Static and dynamical properties of weakly coupled antiferromagnetic spin
chains are treated using a mean--field approximation for the interchain
coupling and exact results for the resulting effective one--dimensional
problem. Results for staggered magnetization, N\'eel temperature and spin wave
excitations are in agreement with experiments on $\rm KCuF_3$. The existence of
a narrow longitudinal mode is predicted. The results are in agreement with
general scaling arguments, contrary to spin wave theory.",9604144v2
1996-10-14,Low Temperature Properties of Quantum Antiferromagnetic Chains with Alternating Spins S=1 and 1/2,"We study the low-temperature properties of S=1 and 1/2 alternating spin
chains with antiferromagnetic nearest-neighbor exchange couplings using
analytical techniques as well as a quantum Monte Carlo method. The spin-wave
approach predicts two different low-lying excitations, which are gapped and
gapless, respectively. The structure of low-lying levels is also discussed by
perturbation theory in the strength of the Ising anisotropy. These analytical
findings are compared with the results of quantum Monte Carlo calculations and
it turns out that spin-wave theory well describes the present system. We
conclude that the quantum ferrimagnetic chain exhibits both ferromagnetic and
antiferromagnetic aspects.",9610109v1
1999-08-31,Linear spin and orbital wave theory for undoped manganites,"We present a linear spin and orbital wave theory to account for the spin and
orbital orderings observed experimentally in undoped manganite. It is found
that the anisotropy of the magnetic structure is closely related to the orbital
ordering, and the Jahn-Teller effect stabilizes the orbital ordering. The phase
diagram and the low energy excitation spectra for both spin and orbital
orderings are obtained. The calculated critical temperatures can be
quantitatively comparable to the experimental data.",9908464v1
1999-10-04,Longitudinal magnetic excitations in classical spin systems,"Using spin dynamics simulations we predict the splitting of the longitudinal
spin wave peak in all antiferromagnets with single site anisotropy into two
peaks separated by twice the energy gap at the Brillouin zone center. This
phenomenon has yet to be observed experimentally but can be easily investigated
through neutron scattering experiments on MnF$_2$ and FeF$_2$. We have also
determined that for all classical Heisenberg models the longitudinal
propagative excitations are entirely multiple spin-wave in nature.",9910031v1
2000-01-31,Magnon dispersions in quantum Heisenberg ferrimagnetic chains at zero temperature,"Within the Dyson-Maleev boson formalism, we study the zero-temperature magnon
dispersions in a family of one-dimensional quantum Heisenberg ferrimagnets
composed of two different spins $(S_1,S_2)$ in the elementary cell. It is shown
that the spin-wave theory can produce precise quantitative results for the
low-energy excitations. The spin-stiffness constant $\rho_s$ and the optical
magnon gap $\Delta$ of different $(S_1,S_2)$ ferrimagnetic systems are
calculated, respectively, to second and third order in the quasiparticle
interaction. The spin-wave results are compared with available numerical
estimates.",0001441v1
2001-11-28,Spin Excitations in La2CuO4: Consistent Description by Inclusion of Ring-Exchange,"We consider the square lattice Heisenberg antiferromagnet with plaquette ring
exchange and a finite interlayer coupling leading to a consistent description
of the spin-wave excitation spectrum in La2CuO4. The values of the in-plane
exchange parameters, including ring-exchange J_{\Box}, are obtained
consistently by an accurate fit to the experimentally observed in-plane
spin-wave dispersion, while the out-of-plane exchange interaction is found from
the temperature dependence of the sublattice magnetization at low temperatures.
The fitted exchange interactions J=151.9 meV and J_{\Box}=0.24 J give values
for the spin stiffness and the Neel temperature in excellent agreement with the
experimental data.",0111533v1
2002-11-15,Collective modes in unconventional density waves,"We have investigated the collective modes of unconventional charge and spin
density waves (UCDW, USDW) in quasi-one dimensional systems in random phase
approximation. The density correlator regains its normal state form due to the
phase degree of freedom of the condensate. The possible effect of impurities is
also discussed. From this, the current-current correlation function is
evaluated through charge conservation. The spin susceptibility of USDW remains
anisotropic an spite of the lack of any periodic modulation of the spin
density. In UCDW, the spin response gets weaker in all three directions as the
temperature is lowered.",0211316v1
2003-06-07,Microscopic Wave Functions of Spin Singlet and Nematic Mott States of Spin-One Bosons in High Dimensional Bipartite Lattices,"We present microscopic wave functions of spin singlet Mott insulating states
and nematic Mott insulating states. We also investigate quantum phase
transitions between the spin singlet Mott phase and the nematic Mott phase in
both large-N limit and small-N limit (N being the number of particles per site)
in high dimensional bipartite lattices. In the mean field approximation
employed in this article we find that phase transitions are generally weakly
first order.",0306198v2
2004-02-25,Spin Dynamics of a Canted Antiferromagnet in a Magnetic Field,"The spin dynamics of a canted antiferromagnet with a quadratic spin-wave
dispersion near $\vq =0$ is shown to possess a unique signature. When the
anisotropy gap is negligible, the spin-wave stiffness $\dsw (\vq, B) =
(\omega_{\vq}-B)/q^2$ depends on whether the limit of zero field or zero
wavevector is taken first. Consequently, $\dsw $ is a strong function of
magnetic field at a fixed wavevector. Even in the presence of a sizeable
anisotropy gap, the field dependence of both $\dsw $ and the gap energy
distinguishes a canted antiferromagnet from a phase-separated mixture
containing both ferromagnetic and antiferromagnetic regions.",0402633v2
2004-06-21,"Magnetic susceptibility, exchange interactions and spin-wave spectra in the local spin density approximation","Starting from exact expression for the dynamical spin susceptibility in the
time-dependent density functional theory a controversial issue about exchange
interaction parameters and spin-wave excitation spectra of itinerant electron
ferromagnets is reconsidered. It is shown that the original expressions for
exchange integrals based on the magnetic force theorem (J. Phys. F14 L125
(1984)) are optimal for the calculations of the magnon spectrum whereas static
response function is better described by the ``renormalized'' magnetic force
theorem by P. Bruno (Phys. Rev. Lett. 90, 087205 (2003)). This conclusion is
confirmed by the {\it ab initio} calculations for Fe and Ni.",0406488v1
2005-02-22,Dynamics of weakly coupled random antiferromagnetic quantum spin chains,"We study the low-energy collective excitations and dynamical response
functions of weakly coupled random antiferromagnetic spin-1/2 chains. The
interchain coupling leads to Neel order at low temperatures. We use the
real-space renormalization group technique to tackle the intrachain couplings
and treat the interchain couplings within the Random Phase Approximation (RPA).
We show that the system supports collective spin wave excitations, and
calculate the spin wave velocity and spectra weight within RPA. Comparisons
will be made with inelastic neutron scattering experiments
quasi-one-dimensional disordered spin systems such as doped CuGeO$_3$",0502530v2
2005-04-12,Spin-charge separation in cold Fermi-gases: a real time analysis,"Using the adaptive time-dependent density-matrix renormalization group method
for the 1D Hubbard model, the splitting of local perturbations into separate
wave packets carrying charge and spin is observed in real-time. We show the
robustness of this separation beyond the low-energy Luttinger liquid theory by
studying the time-evolution of single particle excitations and density wave
packets. A striking signature of spin-charge separation is found in 1D cold
Fermi gases in a harmonic trap at the boundary between liquid and
Mott-insulating phases. We give quantitative estimates for an experimental
observation of spin-charge separation in an array of atomic wires.",0504299v2
2006-06-30,Spin-Wave Lifetimes Throughout the Brillouin Zone,"We use a neutron spin-echo method with $\mu$eV resolution to determine the
lifetimes of spin waves in the prototypical antiferromagnet MnF$_2$ over the
entire Brillouin zone. A theory based on the interaction of magnons with
longitudinal spin fluctuations provides an excellent, parameter-free
description of the data, except at the lowest momenta and temperatures. This is
surprising, given the prominence of alternative theories based on magnon-magnon
interactions in the literature. The results and technique open up a new avenue
for the investigation of fundamental concepts in magnetism. The technique also
allows measurement of the lifetimes of other elementary excitations (such as
lattice vibrations) throughout the Brillouin zone.",0606814v1
2000-09-20,Gravitational waves and spinning test particles,"The motion of a classical spinning test particle in the field of a weak plane
gravitational wave is studied. It is found that the characteristic dimensions
of the particle's orbit is sensitive to the ratio of the spin to the mass of
the particle. The results are compared with the corresponding motion of a
particle without spin.",0009070v1
2005-10-25,Beam Splitter for Spin Waves in Quantum Spin Network,"We theoretically design and analytically study a controllable beam splitter
for the spin wave propagating in a star-shaped (e.g., a $Y$-shaped beam) spin
network. Such a solid state beam splitter can display quantum interference and
quantum entanglement by the well-aimed controls of interaction on nodes. It
will enable an elementary interferometric device for scalable quantum
information processing based on the solid system.",0510194v3
2007-04-26,Coupling of phonons and spin waves in triangular antiferromagnet,"We investigate the influence of the spin-phonon coupling in the triangular
antiferromagnet where the coupling is of the exchange-striction type. The
magnon dispersion is shown to be modified significantly at wave vector (2pi,0)
and its symmetry-related points, exhibiting a roton-like minimum and an
eventual instability in the dispersion. Various correlation functions such as
equal-time phonon correlation, spin-spin correlation, and local magnetization
are calculated in the presence of the coupling.",0704.3510v2
2007-09-17,Magnetic order and spin fluctuations in low-dimensional insulating systems,"The current theoretical and experimental situations are reviewed for
low-dimensional insulating systems with a low magnetic transition temperature
TM and pronounced short-range magnetic order above this temperature. Both the
standard and self-consistent spin-wave theories are shown to be insufficient to
quantitatively describe the experimental data on these systems.
Field-theoretical approaches taking into account the contribution of the
spin-fluctuation excitations (neglected in the spin-wave theories) to the
thermodynamic properties of ferro- and antiferromagnets are discussed.",0709.2690v1
2008-04-30,Phase diagram of the t-U-J1-J2 chain at half filling,"We investigate the half-filled Hubbard chain with additional nearest- and
next-nearest-neighbor spin exchange, J1 and J2, using bosonization and the
density-matrix renormalization group. For J2 = 0 we find a spin-density-wave
phase for all positive values of the Hubbard interaction U and the Heisenberg
exchange J1. A frustrating spin exchange J2 induces a bond-order-wave phase.
For some values of J1, J2 and U, we observe a spin-gapped metallic Luther-Emery
phase.",0804.4810v1
2008-07-03,Zero-size objects in Riemann-Cartan spacetime,"We use the conservation law of the stress-energy and spin tensors to study
the motion of massive zero-size objects in Riemann-Cartan geometry. The
resultant world line equations turn out to exhibit a novel spin-curvature
coupling. In particular, the spin of the Dirac particle does not couple to the
background curvature. This is a consequence of its truly zero size which
consistently rules out the orbital degrees of freedom. As a test of
consistency, the wave packet solution of the free Dirac equation is considered.
It is shown that the wave packet spin and orbital angular momentum disappear
simultaneously in the zero-size limit.",0807.0596v1
2009-02-20,Properties of high-$T_c$ copper oxides from band models of spin-phonon coupling,"The mechanism of spin-phonon coupling (SPC) and possible consequencies for
the properties of high-$T_C$ copper oxides are presented. The results are based
on ab-initio LMTO band calculations and a nearly free-electron (NFE) model of
the band near $E_F$. Many observed properties are compatible with SPC, as for
the relation between doping and $\vec{q}$ for spin excitations and their energy
dependence. The main pseudogap is caused by SPC and waves along [1,0,0], but it
is suggested that secondary waves, generated along [1,1,0], contribute to a
'waterfall' structure. Conditions for optimal $T_C$, and the possiblities for
spin enhancement at the surface are discussed.",0902.3580v1
2009-07-13,Low Temperature Limit of Stability of Coherent Precession of Spin in the Superfluid 3He-B,"It is shown that instability of homogeneous precession is caused by combined
effect of anisotropy of spin wave velocities and dipole interaction. In the
principal order on the ratio of the Leggett frequency to the Larmor frequency
the increments of growth of spin wave amplitudes are found. The magnitude of
the maximum increment for all deviation angles of spin from its equilibrium
orientation is calculated. The estimation is made of the minimum temperature
down to which the precession is stable.",0907.2119v1
2010-02-16,ADM canonical formulation with spin and application to post-Newtonian approximations,"Recently, different methods succeeded in calculating the spin dynamics at
higher orders in the post-Newtonian (PN) approximation. This is an essential
step toward the determination of more accurate templates for gravitational
waves, to be used in future gravitational wave astronomy. We focus on the
extension of the ADM canonical formalism to spinning binary black holes. Using
the global Poincare invariance of asymptotically flat spacetimes as the most
important guiding consistency condition, this extension can be constructed
order by order in the PN approximation. We were able to reach a high order both
in the spin power and the PN counting.",1002.3057v1
2010-10-17,Exact solution for large amplitude circularly polarized electromagnetic waves in incompressible spin quantum Hall magnetohydrodynamics,"It is shown that incompressible spin quantum Hall magnetohydrodynamics allows
an exact solution for the propagation of a circularly polarized electromagnetic
wave. The solution is obtained assuming a condition between the fluid velocity
and the magnetic field which eliminates the nonlinear terms in Maxwell
equations. As a result of the coupling with spin, the propagation mode depends
on the amplitude of the magnetic field. From the full solution, the limits of
small and large wavenumber are studied obtaining linear and a nonlinear
spin-modified modes.",1010.3452v1
2011-01-18,Magnetic Excitations in the Site-Centered Stripe Phase: Spin Wave Theory of Coupled Three-Leg Ladders,"The success of models of coupled two-leg spin ladders in describing the
magnetic excitation spectrum of La_{2-x}Ba_xCuO_4 had been interpreted
previously as evidence for bond-centered stripes. In a recent article, however,
we have determined the magnetic coupling induced by the charge stripes between
bond- or site-centered spin stripes modeled by two- or three-leg ladders,
respectively. We found that only the site-centered models order. We further
indicated excellent agreement of a fully consistent analysis of coupled
three-leg ladders using a spin wave theory of bond with the experimental data.
Here, we provide a full and detailed account of this analysis.",1101.3434v1
2011-08-05,One-dimensional physics in transition-metal nanowires: Phases and elementary excitations,"We used the Hartree-Fock approximation to classify the electronic phases that
might occur in a transition metal nanowire. The important features of this
situation are orbital degeneracy (or near-degeneracy) and interactions favoring
locally high-spin configurations. In this circumstance, spin density wave and
triplet superconductivity states are favored. If the interactions favor locally
low-spin configurations as in the previously studied spin ladder systems,
orbital density wave and singlet superconductivity are observed.",1108.1389v1
2012-03-07,Anomalous Behavior of Spin Systems with Dipolar Interactions,"We study the properties of spin systems realized by cold polar molecules
interacting via dipole-dipole interactions in two dimensions. Using a spin wave
theory, that allows for the full treatment of the characteristic long-distance
tail of the dipolar interaction, we find several anomalous features in the
ground state correlations and the spin wave excitation spectrum, which are
absent in their counterparts with short range interaction. The most striking
consequence is the existence of true long-range order at finite temperature for
a two-dimensional phase with a broken U(1) symmetry.",1203.1624v2
2013-03-10,Spin Dynamics of Trimers on a Distorted Kagomé Lattice,"We treat the ground state, elementary excitations, and neutron scattering
cross section for a system of trimers consisting of three tightly bound spins
1/2 on a distorted Kagom\'e lattice, subject to isotropic nearest neighbor
(usually antiferromagnetic) Heisenberg interactions. The interactions between
trimers are assumed to be weak compared to the intra trimer interactions. We
compare the spin-wave excitation spectrum of trimers with that obtained from
standard spin-wave theory and attribute the differences at low energy to the
fact that the trimer formulation includes exactly the effects of intra-trimer
zero point motion. Application to existing systems is briefly discussed.",1303.2320v1
2014-10-08,$\mathbb Z_2$ slave-spin theory of a strongly correlated Chern insulator,"We calculate the phase diagram of the topological honeycomb model in the
presence of strong interactions. We concentrate on half filling and employ a
${\mathbb Z}_{2}$ slave-spin method to find a band insulator with staggered
density, a spin-density-wave and a Mott insulating phase. Both the band
insulator and the spin-density wave come in various topological varieties.
Finally, we calculate the response function relevant for lattice modulation
spectroscopy with cold atomic gases in optical lattices.",1410.2001v1
2015-01-26,"Illustration of spin-half wave-functions, and other fractional-spin structures","We provide an illustration of a geometric structure that exhibits the
spin-half wave-function characteristics, namely that its full rotation displays
a phase inversion. We show that general fractional-spin geometric structures
are possible, along with sketchy discussions concerning group-theoretical and
quantum descriptions, as well as pose some queries. Synthesis of a
$(PF_3)_n$-chain polymer in the form of a twisted ring is proposed as a
realization of a quazi-spin-1/3 structure.",1501.06292v1
2018-10-10,The geometro-hydrodynamical formalism of quantum spinning particle,"We present the development of the realistic geometro-hydrodynamical formalism
of quantum mechanics for the spinning particle, that involves the vortical
flows and is based on the idea, that the spinor wave represents a new type of
physical field, propagating in space-time and influencing the corpuscule
embedded in the wave. We assume that this new field created by the intrinsic
spin of the particle and can produce new intrinsic forces and torques affecting
the particle with spin. We derive and discuss physical effects of this field.",1810.04716v1
2021-10-13,Spin elastodynamic motive force,"The spin-motive force (SMF) in a simple ferromagnetic monolayer caused by a
surface acoustic wave is studied theoretically via spin-vorticity coupling
(SVC). The SMF has two mechanisms. The first is the SVC-driven SMF, which
produces the first harmonic electromotive force, and the second is the
interplay between the SVC and the magentoelastic coupling, which produces the
d.c. and second harmonic electromotive forces. We show that these electric
voltages induced by a Rayleigh-type surface acoustic wave can be detected in
polycrystalline nickel. No sophisticated device structures, non-collinear
magnetic structures, or strong spin-orbit materials are used in our approach.
Consequently, it is intended to broaden the spectrum of SMF applications
considerably.",2110.06552v1
2008-06-19,Dirac particle in gravitational field,"Classical dynamics of spinning zero-size objects in an external gravitational
field is derived from the conservation law of the stress-energy and spin
tensors. The resulting world line equations differ from those in the existing
literature. In particular, the spin of the Dirac particle does not couple to
the background curvature. As a check of consistency, the wave packet solution
of the free Dirac equation is considered. The resulting equations are shown to
include a constraint that relates the wave packet spin to its orbital angular
momentum. In the zero-size limit, both contributions to the total angular
momentum disappear simultaneously.",0806.3228v1
2008-06-25,Spin polarized transport driven by square voltage pulses in a quantum dot system,"We calculate current, spin current and tunnel magnetoresistance (TMR) for a
quantum dot coupled to ferromagnetic leads in the presence of a square wave of
bias voltage. Our results are obtained via time-dependent nonequilibrium Green
function. Both parallel and antiparallel lead magnetization alignments are
considered. The main findings include a wave of spin accumulation and spin
current that can change sign as the time evolves, spikes in the TMR signal and
a TMR sign change due to an ultrafast switch from forward to reverse current in
the emitter lead.",0806.4193v1
2016-11-05,Magnonic analog of relativistic Zitterbewegung in an antiferromagnetic spin chain,"We theoretically investigate the spin wave (magnon) excitations in a
classical antiferromagnetic spin chain with easy-axis anisotropy. We obtain a
Dirac-like equation by linearizing the Landau- Lifshitz-Gilbert equation in
this antiferromagnetic system, in contrast to the ferromagnetic system in which
a Schr\""{o}dinger equation is derived. The Hamiltonian operator in the
Dirac-like equation is a pseudo-Hermitian. We compute and demonstrate the
relativistic Zitterbewegung (trembling motion) in the antiferromagnetic spin
chain by measuring the expectation values of the wave packet position.",1611.01512v2
2020-10-05,Localized excitations and scattering of spin waves in ferromagnetic chains containing magnetic nanoclusters,"The spectrum of localized excitations in an anisotropic one-dimensional
ferromagnet containing a spin cluster of arbitrary size is found exactly within
the framework of the discrete Takeno-Homma model. The boundaries of stability
of spin nanoclusters are determined, depending on their size, and the exchange
and the anisotropy parameter of the ferromagnet. The problem of the spin waves
scattering against nanoclusters is solved and explicit analytical expressions
for their reflection and transmission coefficients are obtained. A model of a
metamaterial consisting of weakly interacting magnetic molecular nanoclusters
and possessing revealed dynamic properties is proposed.",2010.01861v1
2022-09-28,Unidirectional magnetic coupling,"We show that interlayer Dzyaloshinskii-Moriya interaction in combination with
non-local Gilbert damping gives rise to unidirectional magnetic coupling. That
is, the coupling between two magnetic layers -- say the left and right layer --
is such that dynamics of the left layer leads to dynamics of the right layer,
but not vice versa. We discuss the implications of this result for the magnetic
susceptibility of a magnetic bilayer, electrically-actuated spin-current
transmission, and unidirectional spin-wave packet generation and propagation.
Our results may enable a route towards spin-current and spin-wave diodes and
further pave the way to design spintronic devices via reservoir engineering.",2209.14179v1
2024-03-15,Chiral-stress-energy-momentum tensor for covariant description of spin and torque densities of light,"The measurement of the spin angular momentum of circularly polarized light by
Beth [Phys. Rev. 50, 115 (1936)] can be explained by using a microscopic torque
density. However, the experiment does not resolve the space- and time-dependent
evolution of the spin density of light and the wave plate and the covariant
form of the microscopic torque density. Here we focus on the covariant
description of the helicity, spin, and torque densities of light in materials
using the chiral-stress-energy-momentum tensor. We also perform simulations of
Gaussian light pulses in quarter-wave-plate geometries made of birefringent and
dielectric materials.",2403.10466v1
2005-09-25,Gravitational wave detection by a spherical antenna: the angular sensitivity of resonators in the TIGA configuration and its variation with sidereal time and galactic longitude,"Experimental projects using spherical antennas to detect gravitational waves
are nowdays a concrete reality. The main purpose of this paper is to give a
possible way of interpreting output data from such a system. Responses of the
five fundamental quadrupole modes and of the six resonators in TIGA
collocations are shown as a function of the incoming direction of the incident
wave. Then, for a source lying in the galactic plane, sidereal time and
galactic longitude dependence is given. Thus, once a candidate source of
gravitational waves is considered, we can exactly predict the resonators'
response as a function of time.",0509095v2
2005-10-17,Phase effects in neutrino conversions during a supernova shock wave,"Neutrinos escaping from a core collapse supernova a few seconds after bounce
pass through the shock wave, where they may encounter one or more resonances
corresponding to $\Delta m^2_{\rm atm}$. The neutrino mass eigenstates in
matter may stay coherent between these multiple resonances, giving rise to
oscillations in the survival probabilities of neutrino species. We provide an
analytical approximation to these inevitable phase effects, that relates the
density profile of the shock wave to the oscillation pattern. The phase effects
are present only if the multiple resonances encountered by neutrinos are
semi-adiabatic, which typically happens for $10^{-5} \lsim \sin^2 \theta_{13}
\lsim 10^{-3}$. The observability of these oscillations is severely limited by
the inability of the detectors to reconstruct the neutrino energy faithfully.
For typical shock wave profiles, the detection of these phase effects seems
rather unlikely. However, if the effects are indeed identified in the $\nuebar$
spectra, they would establish inverted hierarchy and a nonzero value of
$\theta_{13}$.",0510219v3
2002-10-01,Quantum chaos in optical systems: The annular billiard,"We study the dielectric annular billiard as a quantum chaotic model of a
micro-optical resonator. It differs from conventional billiards with hard-wall
boundary conditions in that it is partially open and composed of two dielectric
media with different refractive indices. The interplay of reflection and
transmission at the different interfaces gives rise to rich dynamics of
classical light rays and to a variety of wave phenomena. We study the ray
propagation in terms of Poincare surfaces of section and complement it with
full numerical solutions of the corresponding wave equations. We introduce and
develop an S-matrix approach to open optical cavities which proves very
suitable for the identification of resonances of intermediate width that will
be most important in future applications like optical communication devices. We
show that the Husimi representation is a useful tool in characterising
resonances and establish the ray-wave correspondence in real and phase space.
While the simple ray picture provides a good qualitative description of certain
system classes, only the wave description reveals the quantitative details.",0210002v1
2006-03-13,Resonant coupling between bulk waves and guided modes in a dielectric slab with a thick holographic grating,"What we believe to be a new type of resonant coupling of an incident bulk
wave into guided modes of a slab with a thick holographic grating is shown to
occur in the presence of strong frequency detunings of the Bragg condition.
This happens through the reflection of the strongly noneigen +1 diffracted
order with the slab-grating boundaries, the resultant reflected waves forming a
guided slab mode. Rigorous coupled-wave analysis is used for the numerical
analysis of the predicted resonant effects. Possible applications include
enhanced options for the design of multiplexing and demultiplexing systems,
optical signal-processing devices, optical sensors, and measurement techniques.",0603096v1
2006-07-12,Evanescent wave interference and the total transparency of a warm high-density plasma slab,"It is shown that an overcritical density plasma slab can be totally
transparent to a \textit{p}-polarized obliquely incident electromagnetic wave.
High transparency is achieved due to the interference of the evanescent waves
in the subcritical region. The transmission coefficient has the resonant
character due to the excitation of a plasma surface mode (plasmon-polariton).
It is crucial that two evanescent waves have certain phase shift to provide
non-zero energy flux through non-transparent region. The required phase shift
is obtained at the exact resonance and corresponds to the absolute
transparency. In a warm plasma case, the excitation of the propagating
longitudinal (electrostatic) modes becomes possible. We demonstrate that these
longitudinal excitations facilitate the total transparency of an opaque plasma
slab creating additional resonances in the transmission property of the system.",0607125v1
2007-12-17,Parametric Resonance and Cosmological Gravitational Waves,"We investigate the production of gravitational waves due to quantum
fluctuations of the vacuum during the transition from the inflationary to the
radiation-dominated eras of the universe, assuming this transition to be
dominated by the phenomenon of parametric resonance. The energy spectrum of the
gravitational waves is calculated using the method of continuous Bogoliubov
coefficients, which avoids the problem of overproduction of gravitons at large
frequencies. We found, on the sole basis of the mechanism of quantum
fluctuations, that the resonance field leaves no explicit and distinctive
imprint on the gravitational-wave energy spectrum, apart an overall upward or
downward translation. Therefore, the main features in the spectrum are due to
the inflaton field, which leaves a characteristic imprint at frequencies of the
order of MHz/GHz.",0712.2697v1
2008-05-23,Hydrodynamical Simulations of the Barred Spiral Galaxy NGC 6782,"NGC 6782 is an early-type barred spiral galaxy exhibiting a rich and complex
morphology with multiple ring patterns. To provide a physical understanding of
its structure and kinematical properties, two-dimensional hydrodynamical
simulations have been carried out. Numerical calculations reveal that the
striking features in NGC 6782 can be reproduced provided that the gas flow is
governed by the gravitational potential associated with a slowly rotating
strong bar. In particular, the response of the gaseous disk to the bar
potential leads to the excitation of spiral density waves at the inner Lindblad
resonance giving rise to the appearance of a nearly circular nuclear ring with
a pair of dust lanes. For a sufficiently strong bar potential, the inner 4:1
spiral density waves are also excited. The interaction of the higher harmonic
waves with the waves excited at the inner Lindblad resonance and confined by
the outer Lindblad resonance results in the observed diamond-shaped (or pointy
oval) inner ring structure. The overall gas morphology and kinematical features
are both well reproduced by the model provided that the pattern speed of the
bar is $\sim 25$ km s$^{-1}$ kpc$^{-1}$.",0805.3613v1
2008-10-21,Electromagnetic radiation and resonance phenomena in quantum mechanics,"It is demonstrated that, if one remains in the framework of quantum mechanics
taken alone, stationary states (energy eigenstates) are in no way singled out
with respect to nonstationary ones, and moreover the stationary states would be
difficult if possible to realize in practice. Owing to the nonstationary states
any quantum system can absorb or emit energy in arbitrary continuous amounts.
The peculiarity of the stationary states appears only if electromagnetic
radiation that must always accompany nonstationary processes in real systems is
taken into account. On the other hand, when the quantum system absorbs or emits
energy in the form of a wave the determining role is played by resonance
interaction of the system with the wave. Here again the stationary states
manifest themselves. These facts and influence of the resonator upon the
incident wave enable one to explain all effects ascribed to manifestation of
the corpuscular properties of light (the photoelectric effect, the Compton
effect etc.) solely on a base of the wave concept of light.",0810.3773v3
2010-09-13,Ray model and ray-wave correspondence in coupled optical microdisks,"We introduce a ray model for coupled optical microdisks, in which we select
coupling-efficient rays among the splitting rays. We investigate the resulting
phase-space structure and report island structures arising from the
ray-coupling between the two microdisks. We find the microdisks's refractive
index to influence the phase-space structure and calculate the stability and
decay rates of the islands. Turning to ray-wave correspondence, we find many
resonances to be directly related to the presence of these islands. We study
the relation between the (ray-picture originating) island structures and the
(wave-picture originating) spectral properties of resonances, especially the
leakiness of the resonances which is represented as the imaginary part of the
complex wave vector.",1009.2332v1
2010-10-21,Polarization modulation by tunable electromagnetic metamaterial reflector/absorber,"We propose a polarization modulation scheme of electromagnetic (EM) waves
through reflection of a tunable metamaterial reflector/absorber. By
constructing the metamaterial with resonant unit cells coupled by diodes, we
demonstrate that the EM reflections for orthogonal polarized incident waves can
be tuned independently by adjusting the bias voltages on the corresponding
diodes. Owing to this feature, the reflected EM waves can be electrically
controlled to a linear polarization with continuously tunable azimuth angle
from 0o to 90o at the resonant frequency, or an elliptical polarization with
tunable azimuth angle of the major axis when off the resonant frequency. The
proposed property has been verified through both numerical simulations and
experimental measurements at microwave band, which enables us to electrically
modulate the polarization state of EM waves flexibly.",1010.4378v1
2011-08-05,New experiments on the study of the electric activity of He II at the excitation of second-sound waves,"We present the results of new experiments on the observation of the electric
response of superfluid helium (He II) at the excitation of second-sound waves
in it. We used an acoustic resonator with dielectric case, in which the
measurements of the electric and thermal signals were carried on simultaneously
due to the disposition of a measuring electrode and a bolometer on the face
wall. We measured the potential differences between the face electrodes, as
well as between ring metallic electrodes disposed along the resonator case
which were insulated from one another and from helium. It is shown that the
distribution of the electric potential along the resonator coincides with that
of the temperature in a standing second-sound wave. It is established that the
ratio {\Delta}T/{\Delta}U in a second-sound wave is a constant equal to
2.3{\cdot}10^(4) K/V in the whole regions of temperatures, frequencies, and
heat flow powers under study.",1108.1272v1
2011-10-24,Water waves over a rough bottom in the shallow water regime,"This is a study of the Euler equations for free surface water waves in the
case of varying bathymetry, considering the problem in the shallow water
scaling regime. In the case of rapidly varying periodic bottom boundaries this
is a problem of homogenization theory. In this setting we derive a new model
system of equations, consisting of the classical shallow water equations
coupled with nonlocal evolution equations for a periodic corrector term. We
also exhibit a new resonance phenomenon between surface waves and a periodic
bottom. This resonance, which gives rise to secular growth of surface wave
patterns, can be viewed as a nonlinear generalization of the classical Bragg
resonance. We justify the derivation of our model with a rigorous mathematical
analysis of the scaling limit and the resulting error terms. The principal
issue is that the shallow water limit and the homogenization process must be
performed simultaneously. Our model equations and the error analysis are valid
for both the two- and the three-dimensional physical problems.",1110.5155v1
2012-04-10,Resonant behaviour of an oscillating wave energy converter in a channel,"A mathematical model is developed to study the behaviour of an oscillating
wave energy converter in a channel. During recent laboratory tests in a wave
tank, peaks in the hydrodynamic actions on the converter occurred at certain
frequencies of the incident waves. This resonant mechanism is known to be
generated by the transverse sloshing modes of the channel. Here the influence
of the channel sloshing modes on the performance of the device is further
investigated. Within the framework of a linear inviscid potential-flow theory,
application of the Green theorem yields a hypersingular integral equation for
the velocity potential in the fluid domain. The solution is found in terms of a
fast-converging series of Chebyshev polynomials of the second kind. The
physical behaviour of the system is then analysed, showing sensitivity of the
resonant sloshing modes to the geometry of the device, that concurs in
increasing the maximum efficiency. Analytical results are validated with
available numerical and experimental data.",1204.2164v1
2013-04-10,Current Sheets and Collisionless Damping in Kinetic Plasma Turbulence,"We present the first study of the formation and dissipation of current sheets
at electron scales in a wave-driven, weakly collisional, 3D kinetic turbulence
simulation. We investigate the relative importance of dissipation associated
with collisionless damping via resonant wave-particle interactions versus
dissipation in small-scale current sheets in weakly collisional plasma
turbulence. Current sheets form self-consistently from the wave-driven
turbulence, and their filling fraction is well correlated to the electron
heating rate. However, the weakly collisional nature of the simulation
necessarily implies that the current sheets are not significantly dissipated
via Ohmic dissipation. Rather, collisionless damping via the Landau resonance
with the electrons is sufficient to account for the measured heating as a
function of scale in the simulation, without the need for significant Ohmic
dissipation. This finding suggests the possibility that the dissipation of the
current sheets is governed by resonant wave-particle interactions and that the
locations of current sheets correspond spatially to regions of enhanced
heating.",1304.2958v2
2014-11-16,Tunneling and mode conversion of fast magnetosonic waves in the magnetospheres of Earth and Mercury,"Narrow-band linearly polarized waves, having a resonant structure and a peak
frequency between the local cyclotron frequency of protons and heavy ions, have
been detected in the magnetospheres of Earth and of Mercury. Some of these wave
events have been suggested to be driven by linear mode conversion (MC) of the
fast magnetosonic waves at the ion-ion hybrid (IIH) resonances. Since the
resonant IIH frequency is linked to the plasma composition, solving the inverse
problem allows one to infer the concentration of the heavy ions from the
measured frequency spectra. In this paper, we identify the conditions when the
MC efficiency is maximized in the magnetospheric plasmas and discuss how this
can be applied for estimating the heavy ion concentration in the magnetospheres
of Earth and Mercury.",1411.4254v1
2015-02-06,Traveling waves for the Mass in Mass model of granular chains,"In the present work, we consider the mass in mass (or mass with mass) system
of granular chains, namely a granular chain involving additionally an internal
resonator. For these chains, we rigorously establish that under suitable
""anti-resonance"" conditions connecting the mass of the resonator and the speed
of the wave, bell-shaped traveling wave solutions continue to exist in the
system, in a way reminiscent of the results proven for the standard granular
chain of elastic Hertzian contacts. We also numerically touch upon settings
where the conditions do not hold, illustrating, in line also with recent
experimental work, that non-monotonic waves bearing non-vanishing tails may
exist in the latter case.",1502.01995v1
2015-03-28,A Mechanical Analog of the Two-bounce Resonance of Solitary Waves: Modeling and Experiment,"We describe a simple mechanical system, a ball rolling along a
specially-designed landscape, that mimics the dynamics of a well known
phenomenon, the two-bounce resonance of solitary wave collisions, that has been
seen in countless numerical simulations but never in the laboratory. We provide
a brief history of the solitary wave problem, stressing the fundamental role
collective-coordinate models played in understanding this phenomenon. We derive
the equations governing the motion of a point particle confined to such a
surface and then design a surface on which to roll the ball, such that its
motion will evolve under the same equations that approximately govern solitary
wave collisions. We report on physical experiments, carried out in an
undergraduate applied mathematics course, that seem to verify one aspect of
chaotic scattering, the so-called two-bounce resonance.",1503.08315v1
2016-02-15,Shear to longitudinal mode conversion via second harmonic generation in a two-dimensional microscale granular crystal,"Shear to longitudinal mode conversion via second harmonic generation is
studied theoretically and computationally for plane waves in a two-dimensional,
adhesive, hexagonally close-packed microscale granular medium. The model
includes translational and rotational degrees of freedom, as well as normal and
shear contact interactions. We consider fundamental frequency plane waves in
all three linear modes, which have infinite spatial extent and travel in one of
the high-symmetry crystal directions. The generated second harmonic waves are
longitudinal for all cases. For the lower transverse-rotational mode, an
analytical expression for the second harmonic amplitude, which is derived using
a successive approximations approach, reveals the presence of particular
resonant and antiresonant wave numbers, the latter of which is prohibited if
rotations are not included in the model. By simulating a lattice with adhesive
contact force laws, we study the effectiveness of the theoretical analysis for
non-resonant, resonant, and antiresonant cases. This work is suitable for the
analysis of microscale and statically compressed macroscale granular media, and
should inspire future studies on nonlinear two- and three-dimensional granular
systems in which interparticle shear coupling and particle rotations play a
significant role.",1602.04587v1
2016-10-04,The spectrum of light isovector mesons with $C=+1$ from the COMPASS experiment,"Based on the largest event sample of diffractively produced
$\pi^-\pi^-\pi^+$, obtained by a pion beam of $190~\rm{GeV/c}$ momentum, the
COMPASS collaboration has performed the most advanced partial wave analysis on
multi-body final states, using the isobar model. The large number of waves
included in the analysis reduces truncation effects. We have used fourteen out
of a total of eighty-eight waves, to extract resonance parameters for eleven
light meson candidates, most of them observed previously. The coherence of the
analysis and the large variety of systematic studies has allowed to determine
mass and width of most $a_{J}$ and $\pi_{J}$ states with six different values
of $J^{PC}$ below a mass of $2.1~\rm{GeV/c^2}$, with high confidence. We
exploited that the production rates of resonant and non-resonant contributions
in these fourteen waves vary differently with the four-momentum transfer
squared in the reaction. In addition, we have performed the first isobar-freed
analysis in diffraction, from which we have determined the shape of the
$[\pi\pi]_{S-wave}$ isobar for different $J^{PC}$ of the $3\pi$ system.",1610.01231v1
2019-11-25,Emulating tightly bound electrons in crystalline solids using mechanical waves,"Solid state physics deals with systems composed of atoms with strongly bound
electrons. The tunneling probability of each electron is determined by
interactions that typically extend to neighboring sites, as their corresponding
wave amplitudes decay rapidly away from an isolated atomic core. This kind of
description is essential to material science, and it rules the electronic
transport properties of metals, insulators and other condensed matter systems.
The corresponding phenomenology is well captured by tight-binding models, where
the electronic band structure emerges from atomic orbitals of isolated atoms
plus their coupling to neighboring sites in a cristal. In this work, a
mechanical system that emulates dynamically a tightly bound electron is built.
This is done by connecting mechanical resonators via locally periodic aluminum
bars acting as couplers. When the frequency of a particular resonator lies
within the frequency gap of a coupler, the vibrational wave amplitude imitates
a bound electron orbital. The localization of the wave at the resonator site
and its exponential decay along the coupler are experimentally verified. The
quantum dynamical tight-binding model and frequency measurements in mechanical
structures show an excellent agreement.",1911.11272v1
2018-11-25,Electro-opto-mechanical radio-frequency oscillator driven by guided acoustic waves in standard single-mode fiber,"An opto-electronic radio-frequency oscillator that is based on forward
scattering by the guided acoustic modes of a standard single-mode optical fiber
is proposed and demonstrated. An optical pump wave is used to stimulate
narrowband, resonant guided acoustic modes, which introduce phase modulation to
a co-propagating optical probe wave. The phase modulation is converted to an
intensity signal at the output of a Sagnac interferometer loop. The intensity
waveform is detected, amplified and driven back to modulate the optical pump.
Oscillations are achieved at a frequency of 319 MHz, which matches the
resonance of the acoustic mode that provides the largest phase modulation of
the probe wave. Oscillations at the frequencies of competing acoustic modes are
suppressed by at least 40 dB. The linewidth of the acoustic resonance is
sufficiently narrow to provide oscillations at a single longitudinal mode of
the hybrid cavity. Competing longitudinal modes are suppressed by at least 38
dB as well. Unlike other opto-electronic oscillators, no radio-frequency
filtering is required within the hybrid cavity. The frequency of oscillations
is entirely determined by the fiber opto-mechanics.",1902.05367v1
2019-06-17,Controlling acoustic waves using magnetoelastic Fano resonances,"We propose and analyze theoretically a class of energy-efficient
magneto-elastic devices for analogue signal processing. The signals are carried
by transverse acoustic waves while the bias magnetic field controls their
scattering from a magneto-elastic slab. By tuning the bias field, one can alter
the resonant frequency at which the propagating acoustic waves hybridize with
the magnetic modes, and thereby control transmission and reflection
coefficients of the acoustic waves. The scattering coefficients exhibit
Breit-Wigner/Fano resonant behaviour akin to inelastic scattering in atomic and
nuclear physics. Employing oblique incidence geometry, one can effectively
enhance the strength of magnetoelastic coupling, and thus countermand the
magnetic losses due to the Gilbert damping. We apply our theory to discuss
potential benefits and issues in realistic systems and suggest further routes
to enhance performance of the proposed devices.",1906.07297v2
2016-12-20,Resonant Scattering and Microscopic Model of Spinless Fermi Gases in One-dimensional Optical Lattices,"We study the effective Bloch-wave scattering of a spinless Fermi gas in
one-dimensional (1D) optical lattices. By tuning the odd-wave scattering
length, we find multiple resonances of Bloch-waves scattering at the bottom
(and the top) of the lowest band, beyond which an attractive (and a repulsive)
two-body bound state starts to emerge. These resonances exhibit comparable
widths in the deep lattice limit, and the finite interaction range plays an
essential role in determining their locations. Based on the exact two-body
solutions, we construct an effective microscopic model for the low-energy
scattering of fermions. The model can reproduce not only the scattering
amplitudes of Bloch-waves at the lowest band bottom/top, but also the
attractive/repulsive bound states within a reasonably large energy range
below/above the band. These results lay the foundation for quantum simulating
topological states in cold Fermi gases confined in 1D optical lattices.",1612.06487v2
2018-04-11,Local sunspot oscillations and umbral dots,"Data analysis of sunspot oscillation based on 6-hr SDO run of observation
showed that low frequency (0.2 < ! < 1 mHz) oscillations are local similar to
three and five minute oscillations. The oscillations in the sunspot are
concentrated in cells of a few arcsec, each of which has its own oscillation
spectrum. The analysis of two scenario for sunspot oscillations leads to
conclusion that local sunspot oscillations occur due to subphotospheric
resonator for slow mhd waves. Empirical models of sunspot atmosphere and the
theory of slow waves in thin magnetic flux tubes is applied to the modeling of
subphotospheric resonator. Spectrum of local oscillations consists of a great
number of lines. This kind of spectrum can occur only if the subphospheric
resonator is a magnetic tube with a rather weak magnetic field.Magnetic tubes
of this sort are umbral dots that appear due to the convective tongues in the
monolithic sunspots. The interrelation of local oscillations with umbral dots
and wave fronts of traveling waves in sunspots is discussed.",1804.03874v1
2021-08-26,Molecular orbitals of an elastic artificial benzene,"Benzene, a hexagonal molecule with formula C$_6$H$_6$, is one of the most
important aromatic hydrocarbons. Its structure arises from the $sp^{2}$
hybridization from which three in-plane $\sigma$-bonds are formed. A fourth
$\pi$-orbital perpendicular to the molecular plane combines with those arising
from other carbon atoms to form $\pi$-bonds, very important to describe the
electronic properties of benzene. Here this $\pi$-system is emulated with
elastic waves. The design and characterization of an artificial mechanical
benzene molecule, composed of six resonators connected through finite phononic
crystals, is reported. The latter structures trap the vibrations in the
resonators and couple them through evanescent waves to neighboring resonators
establishing a tight-binding regime for elastic waves. Our results show the
appearance of a spectrum and wave amplitudes reminiscent of that of benzene.
Finite element simulations and experimental data show excellent agreement with
the H\""uckel model for benzene.",2108.12027v1
2017-03-23,Molecular Hydrogen: a benchmark system for Near Threshold Resonances at higher partial waves,"Benchmark reactions involving molecular hydrogen, such as H$_2$+D or
H$_2$+Cl, provide the ideal platforms to investigate the effect of Near
Threshold Resonances (NTR) on scattering processes. Due to the small reduced
mass of those systems, shape resonances due to particular partial waves can
provide features at scattering energies up to a few Kelvins, reachable in
recent experiments. We explore the effect of NTRs on elastic and inelastic
scattering for higher partial waves $\ell$ in the case of H$_2$+Cl for $s$-wave
and H$_2$+D for $p$-wave scattering, and find that NTRs lead to a different
energy scaling of the cross sections as compared to the well known Wigner
threshold regime. We give a theoretical analysis based on Jost functions for
short range interaction potentials. To explore higher partial waves, we adopt a
three channel model that incorporates all key ingredients, and explore how the
NTR scaling is affected by $\ell$. A short discussion on the effect of the
long-range form of the interaction potential is also provided.",1703.07913v1
2019-01-10,A reaction network approach to the theory of acoustic wave turbulence,"We propose a new approach to study the long time dynamics of the wave kinetic
equation in the statistical description of acoustic turbulence. The approach is
based on rewriting the discrete version of the wave kinetic equation in the
form of a chemical reaction network, then employing techniques used to study
the Global Attractor Conjecture to investigate the long time dynamics of the
newly obtained chemical system. We show that the solution of the chemical
system converges to an equilibrium exponentially in time. In addition, a
resonance broadening modification of the acoustic wave kinetic equation is also
studied with the same technique. For the near-resonance equation, if the
resonance broadening frequency is larger than a threshold, the solution of the
system goes to infinity as time evolves.",1901.03005v2
2019-01-10,Effect of Inhomogeneous magnetic field on Plasma generation in a low magnetic field helicon discharge,"The ionization efficiency of helicon plasma discharge is explored by changing
the low axial magnetic field gradients near the helicon antenna. The highest
plasma density is found for a most possible diverging field near the antenna by
keeping the other operating condition constant. Measurement of axial wave
number together with estimated radial wavenumber suggests the oblique mode
propagation of helicon wave along the resonance cone boundary. Propagation of
helicon wave near the resonance cone angle boundary can excite electrostatic
fluctuations which subsequently can deposit energy in the plasma. This process
has been shown to be responsible for peaking in density in low field helicon
discharges, where the helicon wave propagates at an angle with respect to the
applied uniform magnetic field. The increased efficiency can be explained on
the basis of multiple resonances for multimode excitation by the helicon
antenna due to the availability of a broad range of magnetic field values in
the near field of the antenna when a diverging magnetic field is applied in the
source.",1901.03015v1
2019-08-19,Linear unstable whistler eigenmodes excited by a finite electron beam,"Electron beam-generated whistler waves are widely found in the Earth's space
plasma environment and are intricately involved in a number of phenomena. Here
we study the linear growth of whistler eigenmodes excited by a finite gyrating
electron beam, to facilitate the interpretation of relevant experiments on
beam-generated whistler waves in the Large Plasma Device at UCLA. A linear
instability analysis for an infinite gyrating beam is first performed. It is
shown that whistler waves are excited through a combination of cyclotron
resonance, Landau resonance and anomalous cyclotron resonance, consistent with
our experimental results. By matching the whistler eigenmodes inside and
outside the beam at the boundary, a linear growth rate is obtained for each
wave mode and the corresponding mode structure is constructed. These eigenmodes
peak near the beam boundary, leak out of the beam region and decay to zero far
away from the beam.",1908.06961v1
2019-09-21,Resonant absorption of kink oscillations in coronal flux tubes with continuous magnetic twist,"There are observational evidences for the existence of twisted magnetic field
in the solar corona. Here, we have investigated resonant damping of the
magnetohydrodynamic (MHD) kink waves in magnetic flux tubes. A realistic model
of the tube with continuous magnetic twist and radially inhomogeneous density
profile has been considered. We have obtained the dispersion relation of the
kink wave using the solution to the linear MHD equations outside the density
inhomogeneity and the appropriate connection formula to the solutions across
the thin transitional boundary layer. The dependence of the oscillation
frequency and damping rate of the waves on the twist parameter and longitudinal
wavenumber has been investigated. For the flux tube parameters considered in
this paper, we obtain rapid damping of the kink waves comparable to the
observations. In order to justify this rapid damping, depending on the sign of
the azimuthal kink mode number, $m=+1$ or $m=-1$, the background magnetic field
must have left handed or right handed twisted profile, respectively. For the
model considered here, the resonant absorption occurs only when the twist
parameter is in a range specified by the density contrast.",1909.09787v1
2020-05-18,Generalized uncertainty principle in resonant detectors of gravitational waves,"With the direct detection of gravitational waves by advanced LIGO detector, a
new ""window"" to quantum gravity phenomenology has been opened. At present,
these detectors achieve the sensitivity to detect the length variation ($\delta
L$), $\mathcal{O} \approx 10^{-17}-10^{-21}$ meter. Recently a more stringent
upperbound on the dimensionless parameter $\beta_0$, bearing the effect of
generalized uncertainty principle has been given which corresponds to the
intermediate length scale $l_{im}= \sqrt{\beta_0} l_{pl} \sim 10^{-23} m$.
Hence the flavour of the generalized uncertainty principle can be realised by
observing the response of the vibrations of phonon modes in such resonant
detectors in the near future. In this paper, therefore, we calculate the
resonant frequencies and transition rates induced by the incoming gravitational
waves on these detectors in the generalized uncertainty principle framework. It
is observed that the effects of the generalized uncertainty principle bears its
signature in both the time independent and dependent part of the gravitational
wave-harmonic oscillator Hamiltonian. We also make an upper bound estimate of
the GUP parameter.",2005.09454v2
2023-01-02,A multiple scattering formulation for elastic wave propagation in space-time modulated metamaterials,"Space-time modulation of material parameters offers new possibilities for
manipulating elastic wave propagation by exploiting time-reversal symmetry
breaking. Here we propose and validate a general framework based on the
multiple scattering theory to model space-time modulated elastic metamaterials,
namely elastic waveguides equipped with modulated resonators. The formulation
allows to consider an arbitrary distribution of resonators with a generic
space-time modulation profile and compute the wavefield within and outside the
resonators' region. Additionally, under appropriate assumptions, the same
framework can be exploited to predict the waveguide dispersion relation. We
demonstrate the capabilities of our formulation by revisiting the dynamics of
two representative space-time modulated systems, e.g. the non-reciprocal
propagation of (i) flexural waves along a metabeam and (ii) surface acoustic
waves along a metasurface. Given its flexibility, the proposed method can pave
the way towards the design of novel devices able to realize unidirectional
transport of elastic energy for vibration isolation, signal processing and
energy harvesting purposes.",2301.00874v1
2023-02-21,Ponderomotive Recoil for Electromagnetic Waves,"When waves damp or amplify on resonant particles in a plasma, the nonresonant
particles experience a recoil force that conserves the total momentum between
the particles and electromagnetic fields. This force is important to
understand, as it can completely negate current drive and rotation drive
mechanisms that are predicted on the basis of only the resonant particles.
Here, the existing electrostatic theory of this recoil force is extended to
electromagnetic waves. While the result bears close similarity to historical
fluid theories of laser-plasma interactions, it now incorporates both resonant
and nonresonant particles, allowing momentum conservation to be
self-consistently proven. Furthermore, the result is shown to be generally
valid for kinetic plasmas, which is verified through single-particle hot-plasma
simulations. The new form of the force provides physical insight into the
nature of the generalized Minkowski (plasmon) momentum of geometrical optics,
which is shown to correspond to the momentum gained by the field and
nonresonant particles as the wave is self-consistently ramped up from vanishing
amplitude.",2302.11029v1
2023-08-22,Resonant detectors of gravitational wave in the linear and quadratic generalized uncertainty principle framework,"In this work, we consider a resonant bar detector of gravitational wave in
the generalized uncertainty principle (GUP) framework with linear and quadratic
momentum uncertainties. The phonon modes in these detectors vibrate due to the
interaction with the incoming gravitational wave. In this uncertainty principle
framework, we calculate the resonant frequencies and transition rates induced
by the incoming gravitational waves on these detectors. We observe that the
energy eigenstates and the eigenvalues get modified by the GUP parameters. We
also observe non-vanishing transition probabilities between two adjacent energy
levels due to the existence of the linear order momentum correction in the
generalized uncertainty relation which was not present in the quadratic GUP
analysis [\href{http://dx.doi.org/10.1088/1361-6382/abac45}{Class. Quantum
Grav. 37 (2020) 195006}]. We finally obtain bounds on the dimensionless GUP
parameters using the form of the transition rates obtained during this
analysis.",2308.11215v1
2023-10-10,A Mössbauer Scheme to Probe Gravitational Waves,"Under the local gravitational field, perturbations from high-frequency
gravitational waves can cause a vertical shift of the M\""ossbauer resonance
height. Considering a stationary scheme with the $^{109}$Ag isotope, we
demonstrate that the extremely high precision of M\""ossbauer resonance allows
for competitive gravitational wave sensitivity from KHz up to above MHz
frequencies. M\""ossbauer resonance can offer a novel and small-sized
alternative in the quest of multi-band gravitational wave searches. The
presence of the static gravitational field plays essential role in the
detection mechanism, isotope selection and sensitivity forecast. The proposed
stationary scheme's sensitivity has the potential of significant improvement in
a low-gravity environment.",2310.06607v1
2024-02-01,Helmholtz quasi-resonances are unstable under most single-signed perturbations of the wave speed,"We consider Helmholtz problems with a perturbed wave speed, where the
single-signed perturbation is governed by a parameter $z$. Both the wave speed
and the perturbation are allowed to be discontinuous (modelling a penetrable
obstacle). We show that, for any frequency, for most values of $z$, the
solution operator is polynomially bounded in the frequency.
  This solution-operator bound is most interesting for Helmholtz problems with
strong trapping; recall that here there exist a sequence of real frequencies,
tending to infinity, through which the solution operator grows
superalgebraically, with these frequencies often called
$\textit{quasi-resonances}$. The result of this paper then shows that, at every
quasi-resonance, the superalgebraic growth of the solution operator does not
occur for most single-signed perturbations of the wave speed, i.e.,
quasi-resonances are unstable under most such perturbations.",2402.00843v2
2024-03-19,Investigating Millimeter-Wave Thin-film Superconducting Resonators: A Study Using Tunnel Junction Detectors,"Investigations into the propagation characteristics, specifically loss and
wave velocity, of superconducting coplanar waveguides and microstrip lines were
conducted at a 2 mm wavelength. This was achieved through the measurement of
on-chip half-wavelength resonators, employing
superconductor-insulator-superconductor tunnel junctions as detectors. A
continuous wave millimeter wave probe signal was introduced to the chip via a
silicon membrane-based orthomode transducer. This setup not only facilitated
the injection of the probe signal but also provided a reference path essential
for differential measurements. The observed resonance frequencies aligned
closely with theoretical predictions, exhibiting a discrepancy of only several
percent. However, the measured losses significantly exceeded those anticipated
from quasi-particle loss mechanisms, suggesting the presence of additional loss
factors. Notably, the measurement results revealed that the tangential loss
attributable to the dielectric layer, specifically silicon dioxide, was
approximately $\rm{7\pm 2 \times 10^{-3}}$. This factor emerged as the dominant
contributor to overall loss at temperatures around 4 K.",2403.12342v1
2006-08-22,Propeller activated resonances and the fate of short period cataclysmic variables,"We show that the combination of a weak magnetic propeller and accretion disc
resonances can effectively halt accretion in short period cataclysmic variables
for large fractions of their lifetimes. This may help to explain the
discrepancy between the observed and predicted orbital period distributions of
cataclysmic variables at short periods. Orbital resonances cause the disc to
become eccentric, allowing material to fall back onto the donor star or out of
the system. A weak magnetic field on a rapidly spinning primary star propels
disc material outwards, allowing it to access these resonances. Numerical and
analytic calculations show that this state can be long lived (~10^11 yr). This
is because the magnetic propeller is required only to maintain access to the
resonances, and not to push matter out of the Roche lobe, so that the spin down
time-scale is much longer than for a classical propeller model.",0608458v1
2002-07-02,Decay of an ultracold fermionic lithium gas near a Feshbach resonance,"We studied the magnetic field dependence of the inelastic decay of an
ultracold, optically trapped 6-Li gas of different spin compositions. The spin
mixture of the two lowest hyperfine states showed two decay resonances at 550 G
and 680 G due to two-body collisions, close to the predicted Feshbach resonance
of the elastic s-wave collisions at 800 G. The rapid decay near Feshbach
resonances found in bosonic gases was found to be suppressed by the Pauli
exclusion principle. The observed lifetimes of several hundred milliseconds are
much longer than the expected time for Cooper pair formation and the phase
transition to superfluidity in the vicinity of the Feshbach resonance.",0207046v3
2004-09-02,ESR spectrometer with a loop-gap resonator for cw and time resolved studies in a superconducting magnet,"The design and performance of an electron spin resonance spectrometer
operating at 3 and 9 GHz microwave frequencies combined with a 9 T
superconducting magnet is described. The probehead contains a compact two-loop,
one gap resonator and is embedded in the variable temperature insert of the
magnet enabling measurements in the 0- 9 T magnetic field and 1.5-400 K\
temperature range. The spectrometer allows studies on systems where resonance
occurs at fields far above the $g$ $\approx 2$ paramagnetic condition such as
in strongly interacting spin systems. The low quality factor of the resonator
allows time resolved experiments such as e.g. longitudinally detected ESR. We
demonstrate the performance of the spectrometer on the MgB$_{2}$ superconductor
and the RbC$_{60}$ conducting alkaline fulleride polymer.",0409051v1
2001-11-23,First Measurement of the Double Spin Asymmetry in $\vec{e}\vec{p}\to e' π^+ n$ in the Resonance Region,"The double spin asymmetry in the $\vec{e}\vec{p}\to e' \pi^+ n$ reaction has
been measured for the first time in the resonance region for four-momentum
transfer $Q^2=0.35-1.5$ GeV$^2$. Data were taken at Jefferson Lab with the CLAS
detector using a 2.6 GeV polarized electron beam incident on a polarized solid
NH$_3$ target. Comparison with predictions of phenomenological models shows
strong sensitivity to resonance contributions. Helicity-1/2 transitions are
found to be dominant in the second and third resonance regions. The measured
asymmetry is consistent with a faster rise with $Q^2$ of the helicity asymmetry
$A_1$ for the $F_{15}(1680)$ resonance than expected from the analysis of the
unpolarized data.",0111074v2
2006-09-08,Photorecombination of berylliumlike Ti18+: Hyperfine quenching of dielectronic resonances,"The photorecombination spectrum of 48Ti18+ was measured employing the merged
electron-ion beams technique at a heavy-ion storage ring. The experimental
electron-ion collision energy range 0-80 eV comprises all dielectronic
recombination (DR) resonances associated with 2s->2p (Delta N =0) core
excitations as well as trielectronic recombination (TR) resonances that involve
2s2->2p2 core double-excitations. At low collision energies DR resonances are
observed that are associated with the excitation of metastable 2s2p 3P0 primary
ions with nearly infinite lifetime for the isotope 48Ti with zero nuclear spin.
For the isotope 47Ti with nonzero nuclear spin hyperfine quenching of these
resonances occurs. The procedure for obtaining the associated time constant
from a recombination measurement is outlined.",0609072v1
2009-08-06,Resonance as a probe of the electron superconducting gap in BaFe1.9Ni0.1As2,"The discovery of high-transition temperature (high-Tc) superconductivity near
antiferromagnetism in iron arsenides raised the possibility of an
unconventional superconducting mechansim1-8. The observation of clear Fermi
surfaces and nodeless superconducting gaps by angle resolved photoemission9-12
suggests that electron pairing in these materials may be mediated by
quasiparticle excitations between sign reversed hole and electron Fermi
pockets5-8. Although the presence of a 'resonance' in the spin excitation
spectrum found by inelastic neutron scattering13-17 is consistent with this
picture18-20, there has been no direct evidence connecting the resonance to the
superconducting gap energy. Here we show that for the optimally electron doped
BaFe1.9Ni0.1As2 (Tc =20 K, Fig. 1c) iron arsenide superconductor, application
of a magnetic field that suppresses the superconductivity and superconducting
gap energy also reduces the intensity and energy of the resonance. These
results suggest that the energy of the resonance is proportional to the
electron pairing energy, and thus indicate that spin fluctuations are
intimately related to the mechanism of superconductivity in iron arsenides.",0908.0954v1
2010-01-09,Wide spin resonance with an rf-bunched proton beam,"We recently used an rf solenoid to study the widths of rf spin resonances
with both unbunched and bunched beams of 2.1 GeV_c polarized protons stored in
the COSY synchrotron. A map, with unbunched beam at different fixed rf-solenoid
frequencies, showed a very shallow possible depolarization dip at the
resonance. Next we made frequency sweeps of 400Hz, centered at similar
frequencies, which greatly enhanced the dip. But, with a bunched proton beam,
both the fixed-frequency and frequency-sweep techniques produced similar maps,
and both bunched maps showed full beam depolarization over a wide region.
Moreover, both were more than twice as wide as the unbunched dip. This widening
of the proton resonance due to bunching is exactly opposite to the recently
observed narrowing of deuteron resonances due to bunching.",1001.1456v1
2011-03-25,Lasing and transport in a quantum dot-resonator circuit,"We study a double quantum dot system coherently coupled to an electromagnetic
resonator. A current through the dot system can create a population inversion
in the dot levels and, within a narrow resonance window, a lasing state in the
resonator. The lasing state correlates with the transport properties. On one
hand, this allows probing the lasing state via a current measurement. On the
other hand, the resulting narrow current peak allows resolving small
differences in the dot properties, e.g., a small difference in the Zeeman
splittings of the two dots. For realistic situations relaxation processes have
pronounced consequences. Remarkably, they may even enhance the resolution
between different spin states by releasing a trapped population in the
off-resonant spin channel.",1103.5051v2
2011-07-19,Quantum resonant effect of the strongly-driven spin-boson model,"In this paper we discuss both analytically and numerically the rich quantum
dynamics of the spin-boson model driven by a time-independent field of photon.
Interestingly, we predict a new Rabi oscillation, whose period is inversely
proportional to the driving amplitude. More surprisingly, some nonzero resonant
peaks are found for some special values of the \emph{strong} driving regime.
Moreover, for the different resonant positions, the peaks have different
values. Thus, an important application of this resonance effect is to realize
the precision measurement of the relative parameters in experiment. We also
illustrate that this resonant effect arises from the interference of the
nontrivial periodic phase factors induced by the evolution of the coherent
states in two different subspaces. Our predictions may be, in principle,
observed in the solid-state cavity quantum electrodynamics with the ultrastrong
coupling if the driving magnitude of the photon field is sufficiently large.",1107.3634v1
2011-12-22,Magnetic field induced Fabry-Pérot resonances in helical edge states,"We study electronic transport across a helical edge state exposed to a
uniform magnetic ({$\vec B$}) field over a finite length. We show that this
system exhibits Fabry-P\'erot type resonances in electronic transport. The
intrinsic spin anisotropy of the helical edge states allows us to tune these
resonances by changing the direction of the {$\vec B$} field while keeping its
magnitude constant. This is in sharp contrast to the case of non-helical one
dimensional electron gases with a parabolic dispersion, where similar
resonances do appear in individual spin channels ($\uparrow$ and $\downarrow$)
separately which, however, cannot be tuned by merely changing the direction of
the {$\vec B$} field. These resonances provide a unique way to probe the
helical nature of the theory.",1112.5400v2
2012-12-23,Sidebands in Optically Detected Magnetic Resonance Signals of Nitrogen Vacancy Centers in Diamond,"We study features in the optically detected magnetic resonance (ODMR) signals
associated with negatively charged nitrogen-vacancy (NV) centers coupled to
other paramagnetic impurities in diamond. Our results are important for
understanding ODMR line shapes and for optimization of devices based on NV
centers. We determine the origins of several side features to the unperturbed
NV magnetic resonance by studying their magnetic field and microwave power
dependences. Side resonances separated by around 130 MHz are due to hyperfine
coupling between NV centers and nearest-neighbor C-13 nuclear spins. Side
resonances separated by approximately {40, 260, 300} MHz are found to originate
from simultaneous spin flipping of NV centers and single substitutional
nitrogen atoms. All results are in agreement with the presented theoretical
calculations.",1212.5746v3
2013-04-29,The prospects of forming ultracold molecules in $^2Σ$ states by magnetoassociation of alkali-metal atoms with Yb,"We explore the feasibility of producing ultracold diatomic molecules with
nonzero electric and magnetic dipole moments by magnetically associating two
atoms, one with zero electron spin and one with nonzero spin. Feshbach
resonances arise through the dependence of the hyperfine coupling on
internuclear distance. We survey the Feshbach resonances in diatomic systems
combining the nine stable alkali-metal isotopes with those of Yb, focussing on
the illustrative examples of RbYb and CsYb. We show that the resonance widths
may expressed as a product of physically comprehensible terms in the framework
of Fermi's Golden Rule. The resonance widths depend strongly on the background
scattering length, which may be adjusted by selecting the Yb isotope, and on
the hyperfine coupling constant and the magnetic field. In favorable cases the
resonances may be over 100 mG wide.",1304.7674v1
2014-07-18,Coupling of a locally implanted rare-earth ion ensemble to a superconducting micro-resonator,"We demonstrate the coupling of rare-earth ions locally implanted in a
substrate (Gd$^{3+}$ in Al$_{2}$O$_{3}$) to a superconducting NbN
lumped-element micro-resonator. The hybrid device is fabricated by a controlled
ion implantation of rare-earth ions in well-defined micron-sized areas, aligned
to lithographically defined micro-resonators. The technique does not degrade
the internal quality factor of the resonators which remain above $10^{5}$.
Using microwave absorption spectroscopy we observe electron-spin resonances in
good agreement with numerical modelling and extract corresponding coupling
rates of the order of $1$ MHz and spin linewidths of $50 - 65$ MHz.",1407.5064v4
2016-04-23,Telling the spin of the di-photon resonance,"We argue that the spin of the 750 GeV resonance can be determined at the
99.7% confidence level in the di-photon channel with as few as 10 fb$^{-1}$ of
luminosity. This result is true if the resonance is produced by gluon fusion
(independently of the selection cuts) while an appropriate choice of selection
cuts is needed if quark production is sub-dominantly present--which is the case
of the Kaluza-Klein gravitational excitation under the hypothesis of a spin-2
resonance. A proportionally larger luminosity is required if the model for the
spin-2 resonance includes a dominant production by quarks or in the absence of
an efficient separation of the signal from the background.",1604.06948v1
2017-12-29,Resonant pinning spectroscopy with spin-vortex pairs,"Vortex pairs in magnetic nanopillars with strongly coupled cores and pinning
of one of the cores by a morphological defect, are used to perform resonant
pinning spectroscopy, in which a microwave excitation applied to the nanopillar
produces pinning or depinning of the cores only when the excitation is in
resonance with the rotational or gyrational eigenmodes of the specific initial
state of the core-core pair. The shift in the eigenmode frequencies between the
pinned and depinned states is determined experimentally and explained
theoretically, and illustrates the potential for multi-core spin-vortex memory
with resonant writing of information on to various stable vortex pair states.
Further, it is shown how the same resonant spectroscopy techniques applied to a
vortex pair can be used as a sensitive nanoscale probe for characterizing
morphological defects in magnetic films.",1712.10162v2
2017-06-13,Jet-associated resonance spectroscopy,"We present a model-independent study aimed at characterizing the nature of
possible resonances in the jet-photon or jet-$Z$ final state at hadron
colliders. Such resonances are expected in many models of compositeness and
would be a clear indication of new physics. At leading order, in the narrow
width approximation, the matrix elements are parameterized by just a few
constants describing the coupling of the various helicities to the resonance.
We present the full structure of such amplitudes up to spin two and use them to
simulate relevant kinematic distributions that could serve to constrain the
coupling structure. This also generalizes the signal generation strategy that
is currently pursued by ATLAS and CMS to the most general case in the
considered channels. While the determination of the P/CP properties of the
interaction seems to be out of reach within this framework, there is a wealth
of information to be gained about the spin of the resonance and the relative
couplings of the helicities.",1706.04242v2
2018-04-26,Resonant reflection of interacting electrons from an impurity in a quantum wire: interplay of Zeeman and spin-orbit effects,"A single-channel quantum wire with two well-separated Zeeman subbands and in
the presence of a weak spin-orbit coupling is considered. An impurity level
which is split off the upper subband is degenerate with the continuum of the
lower subband. We show that, when the Fermi level lies in the vicinity of the
impurity level, the transport is completely blocked. This is the manifestation
of the effect of resonant reflection and can be viewed as resonant tunneling
between left-moving and right-moving electrons via the impurity level. We
incorporate electron-electron interactions and study their effect on the shape
of the resonant-reflection profile. This profile becomes a two-peak structure,
where one peak is caused by resonant reflection itself, while the origin of the
other peak is reflection from the Friedel oscillations of the electron density
surrounding the impurity.",1804.10283v1
2021-08-24,Higher-order ferromagnetic resonances in periodic arrays of synthetic-antiferromagnet nanodiscs,"We investigate spin dynamics in nanodisc arrays of synthetic-antiferromagnets
(SAF) made of Py/NiCu/Py trilayers, where the NiCu spacer undergoes a Curie
transition at about 200 K. The observed ferromagnetic resonance spectra have
three distinct resonance modes at room temperature, which are fully recreated
in our micromagnetic simulations showing also how the intra-SAF asymmetry can
be used to create and control the higher-order resonances in the structure.
Below the Curie temperature of the spacer, the system effectively transitions
into a single-layer nanodisc array with only two resonance modes. Our results
show how multi-layering of nano-arrays can add tunable GHz functionality
relevant for such rapidly developing fields as magnetic meta-materials,
magnonic crystals, arrays of spin-torque oscillators and neuromorphic
junctions.",2108.10581v1
2021-10-25,"Spin relaxation, Josephson effect and Yu-Shiba-Rusinov states in superconducting bilayer graphene","Bilayer graphene has two non-equivalent sublattices and, therefore, the same
adatom impurity can manifest in spectrally distinct ways-sharp versus broad
resonances near the charge neutrality-depending on the sublattice it adsorbs
at. Employing Green's function analytical methods and the numerical Kwant
package we investigate the spectral and transport interplay between the
resonances and superconducting coherence induced in bilayer graphene by
proximity to an s-wave superconductor. Analyzing doping and temperature
dependencies of quasi-particle spin-relaxation rates, energies of
Yu-Shiba-Rusinov states, Andreev spectra and the supercurrent characteristics
of Josephson junctions we find unique superconducting signatures discriminating
between resonant and off-resonant regimes. Our findings are in certain aspects
going beyond the superconducting bilayer graphene and hold for generic s-wave
superconductors functionalized by the resonant magnetic impurities.",2110.12998v2
2017-01-31,Spin anisotropic interactions of lower-polaritons in the vicinity of polaritonic Feshbach resonance,"We determine experimentally the spinor interaction constants of
lower-polaritons $\alpha_1$ and $\alpha_2$ using resonant pump-probe
spectroscopy with a spectrally narrow pump pulse. Our experimental findings are
analyzed with the Bogoliubov-like theory and mean-field two channel model based
on the lower-polariton and biexciton basis. We find an enhancement of the
attractive interaction and dissipative nonlinearity of lower-polaritons with
anti-parallel spins in the vicinity of the biexciton resonance when the energy
of two lower-polaritons approaches energetically that of the biexciton. These
observations are consistent with the existence of a scattering resonance
between lower-polaritons and biexcitons (polaritonic Feshbach resonance).",1701.09113v2
2019-04-01,Charmed dibaryon resonances in the potential quark model,"Charmed dibaryon states with the spin-parity $J^{\pi}=0^+$, $1^+$, and
$2^+$are predicted for the two-body $Y_cN$ ($=\Lambda_c$, $\Sigma_c$, or
$\Sigma^*_c$) systems. We employ the complex scaling method for the coupled
channel Hamiltonian with the $Y_cN$-CTNN potentials, which were proposed in our
previous study. We find four sharp resonance states near the $\Sigma_c N$ and
$\Sigma^*_c N$ thresholds. From the analysis of the binding energies of partial
channel systems, we conclude that these resonance states are Feshbach
resonances. We compare the results with the $Y_c N$ resonance states in the
heavy quark limit, where the $\Sigma_c N$ and $\Sigma^*_c N$ thresholds are
degenerate, and find that they form two pairs of the heavy-quark doublets in
agreement with the heavy quark spin symmetry.",1904.00586v1
2021-06-22,Doubly Heavy Tetraquark Resonant States,"Spectrum of the doubly heavy tetraquarks, $bb\bar q\bar q$, is studied in a
constituent quark model. Four-body problem is solved in a variational method
where the real scaling technique is used to identify resonant states above the
fall-apart decay thresholds. In addition to the two bound states that were
reported in the previous study we have found several narrow resonant states
above the $BB^*$ and $B^*B^*$ thresholds. Their structures are studied and are
interpreted by the quark dynamics. A narrow resonance with spin-parity
$J^P=1^+$ is found to be a mixed state of a compact tetraquark and a $B^*B^*$
scattering state. This is driven by a strong color Coulombic attraction between
the $bb$ quarks. Negative-parity excited resonances with $J^P=0^-$, $1^-$ and
$2^-$ form a triplet under the heavy-quark spin symmetry. It turns out that
they share a similar structure to the $\lambda$-mode of a singly heavy baryon
as a result of the strongly attractive correlation for the doubly heavy
diquark.",2106.11868v1
2023-03-28,Exploring terahertz-scale exchange resonances in synthetic ferrimagnets with ultrashort optically induced spin currents,"Using spin currents generated by fs laser pulses, we demonstrate excitation
of GHz ferromagnetic resonance and THz ferrimagnetic exchange resonances in
Co/Gd/Co/Gd multilayers by time-resolved magneto-optic Kerr effect
measurements. Varying the Gd layer thickness allows for a tuning of the
resonance spectrum by manipulating the total angular momentum and strength of
effective exchange fields between the antiferromagnetically coupled layers.
Close to the compensation point of angular momentum, a minimum in the frequency
of the exchange-dominated mode and a maximum in the frequency of the
ferromagnetic resonance mode is observed. Finally, to gain better understanding
of the excitation mechanism, we analyze the anomalous variation in the measured
exchange mode amplitude as a function of its frequency. A peak in this
amplitude in the vicinity of the compensation point of angular momentum is
explained using a macrospin model, taking nonlinear effects at finite
precession amplitudes into account.",2303.15985v2
2009-11-13,Two-resonator circuit QED: Dissipative Theory,"We present a theoretical treatment for the dissipative two-resonator circuit
quantum electrodynamics setup referred to as quantum switch. There, switchable
coupling between two superconducting resonators is mediated by a
superconducting qubit operating in the dispersive regime, where the qubit
transition frequency is far detuned from those of the resonators. We derive an
effective Hamiltonian for the quantum switch beyond the rotating wave
approximation and study the dissipative dynamics within a Bloch-Redfield
quantum master equation approach. We derive analytically how the qubit affects
the quantum switch even if the qubit has no dynamics, and we estimate the
strength of this influence. The analytical results are corroborated by
numerical calculations, where coherent oscillations between the resonators, the
decay of coherent and Fock states, and the decay of resonator-resonator
entanglement are studied. Finally, we suggest an experimental protocol for
extracting the damping constants of qubit and resonators by measuring the
quadratures of the resonator fields.",0911.2657v4
2013-07-24,A census of transient orbital resonances encountered during binary inspiral,"Transient orbital resonances have recently been identified as potentially
important to the inspiral of small bodies into large black holes. These
resonances occur as the inspiral evolves through moments in which two
fundamental orbital frequencies, $\Omega_\theta$ and $\Omega_r$, are in a small
integer ratio to one another. Previous work has demonstrated that a binary's
parameters are ""kicked"" each time the inspiral passes through a resonance,
changing the orbit's characteristics relative to a model that neglects resonant
effects. In this paper, we use exact Kerr geodesics coupled to an accurate but
approximate model of inspiral to survey orbital parameter space and estimate
how commonly one encounters long-lived orbital resonances. We find that the
most important resonances last for a few hundred orbital cycles at mass ratio
$10^{-6}$, and that resonances are almost certain to occur during the time that
a large mass ratio binary would be a target of gravitational-wave observations.
Resonances appear to be ubiquitous in large mass ratio inspiral, and to last
long enough that they are likely to affect binary evolution in observationally
important ways.",1307.6483v2
2017-09-30,Multiple critical coupling and sensing in a microresonator-waveguide system,"We study the optical transmission of a waveguide that is side-coupled to a
high-$Q$ circular microresonator. The coupling is critical if the intrinsic
resonator losses equate the coupling losses to the waveguide. When this
happens, the transmittance of the waveguide displays resonance dips with
maximal depth as the frequency is swept through the resonators resonances. We
show that multiple configurations, parameterised by the minimal distance
between the resonator and the waveguide, can lead to critical coupling. Indeed,
for a sufficiently large resonator radius, the flow of power between the
waveguide and the resonator can change sign several times within a single pass.
This leads to an oscillatory coupling parameter as a function of the separation
distance. As a result, multiple geometrical configurations can lead to critical
coupling, even if the waveguide lies in the equatorial plane of the resonator.
These results are explained using coupled-mode theory and full wave numerical
simulations. In the vicinity of secondary or higher-order critical coupling,
the depth of the transmittance dip is very sensitive to the environment. We
discuss how this effect can be exploited for sensing purpose. Alternatively, by
actively controlling the environment in the secondary critical configuration,
the waveguide/resonator system can be driven as an optical switch.",1710.00178v1
2021-04-07,Importance of tidal resonances in extreme-mass-ratio inspirals,"Extreme mass ratio inspirals (EMRIs) will be important sources for future
space-based gravitational-wave detectors. In recent work, tidal resonances in
binary orbital evolution induced by the tidal field of nearby stars or black
holes have been identified as being potentially significant in the context of
extreme mass-ratio inspirals. These resonances occur when the three orbital
frequencies describing the orbit are commensurate. During the resonance, the
orbital parameters of the small body experience a jump leading to a shift in
the phase of the gravitational waveform. In this paper, we treat the tidal
perturber as stationary and restricted to the equatorial plane, and present a
first study of how common and important such resonances are over the entire
orbital parameter space. We find that a large proportion of inspirals encounter
a low-order resonance in the observationally important regime. While the
instantaneous effect of a tidal resonance is small, its effect on the
accumulated phase of the gravitational waveform of an EMRI system can be
significant due to its many cycles in band; we estimate that the effect is
detectable for a significant fraction of sources. We also provide fitting
formulae for the induced change in the constants of motion of the orbit due to
the tidal resonance for several low-order resonances.",2104.03422v2
2020-06-29,Imaging and Spectroscopy of Domains of the Cellular Membrane by Photothermal-Induced Resonance,"We use photothermal induced resonance (PTIR) imaging and spectroscopy, in
resonant and non-resonant mode, to study the cytoplasmic membrane and surface
of intact cells. Non-resonant PTIR images apparently provide rich details of
the cell surface. However we show that non-resonant image contrast does not
arise from the infrared absorption of surface molecules and is instead
dominated by the mechanics of tip-sample contact. In contrast, spectra and
images of the cellular surface can be selectively obtained by tuning the
pulsing structure of the laser to restrict thermal wave penetration to the
surface layer. Resonant PTIR images reveal surface structures and domains that
range in size from about 20 nm to 1 um and are associated to the cytoplasmic
membrane and its proximity. Resonant PTIR spectra of the cell surface are
comparable to far-field IR spectra and provide the first selective measurement
of the IR absorption spectrum of the cellular membrane of an intact cell. In
resonant PTIR images, signal intensity, and therefore contrast, can be ascribed
to a variety of factors, including mechanical, thermodynamic and spectroscopic
properties of the cellular surface. While PTIR images are difficult to
interpret in terms of spectroscopic absorption, they are easy to collect and
provide unique contrast mechanisms without any exogenous labeling. As such they
provide a new paradigm in cellular imaging and membrane biology and can be used
to address a range of critical questions, from the nature of membrane lipid
domains to viral membrane fusion.",2006.16306v1
2022-08-29,Multi Spectral Switchable Infra-Red Reflectance Resonances in Highly Subwavelength Partially Oxidized Vanadium Thin Films,"Phase transition materials are promising for realization of switchable
optics. In this work, we show reflectance resonances in the near-infrared and
long-wave infrared wavelengths in highly subwavelength partially oxidized
Vanadium thin films. These partially oxidized films consist of a multilayer of
Vanadium dioxide and Vanadium as shown using Raman spectroscopy and four-probe
measurements. As Vanadium dioxide is a phase transition material that shows
insulator to metal phase transition at 68 C, the observed infra-red resonances
can be switched with temperature into a high-reflectance state. The wavelength
of these resonances are passively tunable as a function of the oxidation
duration. The obtained reflectance resonance at near-infrared wavelength red
shifts from 1.78 um to 2.68 um with increasing oxidation duration while the
long-wavelength infrared resonance blue shifts from 12.68 um to 9.96 um. To
find the origin of the reflectance resonances, we model the reflectance spectra
as a function of the oxidation duration using the transfer matrix method. The
presented model captures the dual reflectance resonances reasonably well. These
passive wavelength-tunable and switchable resonances with easy to fabricate
lithography-free multilayer structure will be useful for multispectral
applications such as camouflage, spectral selective microbolometer, and thermal
management.",2208.13458v1
2023-05-09,Direct Measurement of A Spatially Varying Thermal Bath Using Brownian Motion,"Micro-mechanical resonator performance is fundamentally limited by the
coupling to a thermal environment. The magnitude of this thermodynamical effect
is typically considered in accordance with a physical temperature, assumed to
be uniform across the resonator's physical span. However, in some
circumstances, e.g. quantum optomechanics or interferometric gravitational wave
detection, the temperature of the resonator may not be uniform, resulting in
the resonator being thermally linked to a spatially varying thermal bath. In
this case, the link of a mode of interest to its thermal environment is less
straightforward to understand. Here, we engineer a distributed bath on a
germane optomechanical platform -- a phononic crystal -- and utilize both
highly localized and extended resonator modes to probe the spatially varying
bath in entirely different bath regimes. As a result, we observe striking
differences in the modes' Brownian motion magnitude. From these measurements we
are able to reconstruct the local temperature map across our resonator and
measure nanoscale effects on thermal conductivity and radiative cooling. Our
work explains some thermal phenomena encountered in optomechanical experiments,
e.g. mode-dependent heating due to light absorption. Moreover, our work
generalizes the typical figure of merit quantifying the coupling of a resonator
mode to its thermal environment from the mechanical dissipation to the overlap
between the local dissipation and the local temperature throughout the
resonator. This added understanding identifies design principles that can be
applied to performance of micro-mechanical resonators.",2305.05616v1
2023-12-20,Flux coupled tunable superconducting resonator,"We present a design and implementation of frequency-tunable superconducting
resonator. The resonance frequency tunability is achieved by flux-coupling a
superconducting LC-loop to a current-biased feedline; the resulting screening
current leads to a change of the kinetic inductance and shift in the resonance
frequency. The thin film aluminum resonator consists of an interdigitated
capacitor and thin line inductors forming a closed superconducting loop. The
magnetic flux from the nearby current feedline induces Meissner shielding
currents in the resonator loop leading to change in the kinetic part of the
total inductance of the resonator. We demonstarte continuous frequency tuning
within 160 MHz around the resonant frequency of 2.7 GHz. We show that: (1)
frequency upconversion is achieved when kHz AC modulation signal is
superimposed onto the DC bias resulting in sidebands to the resonator tone; (2)
three-wave mixing is attained by parametrically pumping the nonlinear kinetic
inductance using a strong RF pump signal in the feedline. The simple
architecture is amenable to large array multiplexing and on-chip integration
with other circuit components. The concept could be applied in flux
magnetometers, upconverters, and parametric amplifiers operating above 4 Kelvin
cryogenic temperatures when alternative high critical temperature material with
high kinetic inductance is used.",2312.12755v1
2023-06-20,Dynamical nuclear spin polarization in a quantum dot with an electron spin driven by electric dipole spin resonance,"We analyze the polarization of nuclear spins in a quantum dot induced by a
single-electron spin that is electrically driven to perform coherent Rabi
oscillations. We derive the associated nuclear-spin polarization rate and
analyze its dependence on the accessible control parameters, especially the
detuning of the driving frequency from the electron Larmor frequency. The
arising nuclear-spin polarization is related to the Hartmann-Hahn effect known
from the NMR literature with two important differences. First, in quantum dots
one typically uses a micro magnet, leading to a small deflection of the
quantization axes of the electron and nuclear spins. Second, the electric
driving wiggles the electron with respect to the atomic lattice. The two
effects, absent in the traditional Hartmann-Hahn scenario, give rise to two
mechanisms of nuclear-spin polarization in gated quantum dots. The arising
nuclear-spin polarization is a resonance phenomenon, achieving maximal
efficiency at the resonance of the electron Rabi and nuclear Larmor frequency
(typically a few or a few tens of MHz). As a function of the driving frequency,
the polarization rate can develop sharp peaks and reach large values at them.
Since the nuclear polarization is experimentally detected as changes of the
electron Larmor frequency, we often convert the former to the latter in our
formulas and figures. In these units, the polarization can reach hundreds of
MHz/s in GaAs quantum dots and at least tens of kHz/s in Si quantum dots. We
analyze possibilities to exploit the resonant polarization effects for
achieving large nuclear polarization and for stabilizing the Overhauser field
through feedback.",2306.11253v2
2012-10-07,Complete classification of discrete resonant Rossby/drift wave triads on periodic domains,"We consider the set of Diophantine equations that arise in the context of the
barotropic vorticity equation on periodic domains, when nonlinear wave
interactions are studied to leading order in the amplitudes. The solutions to
this set of Diophantine equations are of interest in atmosphere (Rossby waves)
and Tokamak plasmas (drift waves), because they provide the values of the
spectral wavevectors that interact resonantly via three-wave interactions.
These come in ""triads"", i.e., groups of three wavevectors.
  We provide the full solution to the Diophantine equations in the case of
infinite Rossby deformation radius. The method is completely new, and relies on
mapping the unknown variables to rational points on quadratic forms of
""Minkowski"" type. Classical methods invented centuries ago by Fermat, Euler,
Lagrange and Minkowski, are used to classify all solutions to our original
Diophantine equations, thus providing a computational method to generate
numerically all the resonant triads in the system. Our method has a clear
computational advantage over brute-force numerical search: on a 10000^2 grid,
the brute-force search would take 15 years using optimised C++ codes, whereas
our method takes about 40 minutes.
  The method is extended to generate quasi-resonant triads, which are defined
by relaxing the resonant condition on the frequencies, allowing for a small
mismatch. Quasi-resonances are robust with respect to physical perturbations,
unlike exact resonances. Therefore, the new method is really valuable in
practical terms. We show that the set of quasi-resonances form an intricate
network of clusters of connected triads, whose structure depends on the value
of the allowed mismatch. We provide some quantitative comparison between the
clusters' structure and the onset of fully nonlinear turbulence in the
barotropic vorticity equation, and provide perspectives for new research.",1210.2036v2
2014-11-10,Comprehensive analysis of the wave function of a hadronic resonance and its compositeness,"We develop a theoretical framework to investigate the two-body composite
structure of a resonance as well as a bound state from its wave function. For
this purpose, we introduce both one-body bare states and two-body scattering
states, and define the compositeness as a fraction of the contribution of the
two-body wave function to the normalization of the total wave function. Writing
down explicitly the wave function for a resonance state obtained with a general
separable interaction, we formulate the compositeness in terms of the position
of the resonance pole, the residue of the scattering amplitude at the pole and
the derivative of the Green function of the free two-body scattering system. At
the same time, our formulation provides the elementariness expressed with the
resonance properties and the two-body effective interaction, and confirms the
sum rule showing that the summation of the compositeness and elementariness
gives unity. In this formulation the Weinberg's relation for the scattering
length and effective range can be derived in the weak binding limit. The
extension to the resonance states is performed with the Gamow vector, and a
relativistic formulation is also established. As its applications, we study the
compositeness of the $\Lambda (1405)$ resonance and the light scalar and vector
mesons described with refined amplitudes in coupled-channel models with
interactions up to the next to leading order in chiral perturbation theory. We
find that $\Lambda (1405)$ and $f_{0}(980)$ are dominated by the $\bar{K} N$
and $K \bar{K}$ composite states, respectively, while the vector mesons $\rho
(770)$ and $K^{\ast} (892)$ are elementary. We also briefly discuss the
compositeness of $N (1535)$ and $\Lambda (1670)$ obtained in a leading-order
chiral unitary approach.",1411.2308v4
1993-01-26,Order of Two-Dimensional Isotropic Dipolar Antiferromagnets,"The question of the existence of order in two-dimensional isotropic dipolar
Heisenberg antiferromagnets is studied. It is shown that the dipolar
interaction leads to a gap in the spin-wave energy and a nonvanishing order
parameter. The resulting finite N\'eel-temperature is calculated for a square
lattice by means of linear spin-wave theory.",9301033v1
1994-10-07,Crossover from Spin-Density-Wave to Neel-like Ground state,"The characterization and evolution of a Spin Density Wave into the Quantum
Neel ground state is considered in the context of a weak coupling theory of the
half-filled Hubbard model. Magnetic properties obtained from this weak coupling
approach in one dimension compare favorably with exact results from Bethe
ansatz (BA). A study of the evolution of several length scales from weak to
strong coupling is also presented.",9410019v1
1994-10-19,Spin Wave Frequency and Critical Dynamics of Ferromagnets Below T_C,"Employing mode-coupling theory we show that the amplitude of the spin wave
frequency scaling function for the isotropic Heisenberg Hamiltonian is
universal. Theoretical and experimental values for Fe, Ni, Co, EuO, and EuS
agree quite well. Recent measurements of the longitudinal line width in Ni are
explained quantitatively.",9410073v1
1997-03-25,"Spin waves and phase diagram of one-dimensional, dipolar antiferromagnets","We report on the properties of a dipolar, antiferromagnetic chain in the
framework of linear spin-wave theory. The phase diagram is calculated for an
arbitrary ratio of dipolar interaction to exchange interaction and for fields
both parallel and perpendicular to the chain direction. The calculated
magnetization is compared with experimental measurements for RbMnBr_3, a quasi
one-dimensional antiferromagnet.",9703218v1
1998-12-15,Spinon Superconductivity and Superconductivities Mediated by Spin-Waves and Phonons in Cuprates,"The disclosure of spinon superconductivity and superconductivity mediated by
spin-waves in hole-doped Bi2212 cuprate raises the question about the origin of
the superconductivity in other cuprates and specially in an electron-doped NCCO
cuprate.",9812245v2
2000-04-18,Topological Defects in Spin Density Waves,"The rich order parameter of Spin Density Waves allows for unusual object of a
complex topological nature: a half-integer dislocation combined with a
semi-vortex of a staggered magnetization. It becomes energetically preferable
to ordinary dislocation due to enhanced Coulomb interactions in the
semiconducting regime. Generation of these objects changes e.g. the narrow band
noise frequency.",0004313v1
2002-01-10,Spin wave dispersion in La2CuO4,"We calculate the antiferromagnetic spin wave dispersion in the half-filled
Hubbard model for a two-dimensional square lattice and find it to be in
excellent agreement with recent high-resolution inelastic neutron scattering
performed on La2CuO4 [Phys. Rev. Lett. 86, 5377 (2001)].",0201151v2
2002-05-07,Spin-wave spectrum in La2CuO4 -- double occupancy and competing interaction effects,"The recently observed spin-wave energy dispersion along the AF zone boundary
in La2CuO4 is discussed in terms of double occupancy and competing interaction
effects in the $t-t'$ Hubbard model on a square lattice.",0205117v1
2005-01-28,Magnetic Phase Transition in FeRh,"Density functional calculations are performed to investigate the phase
transition in FeRh alloy. The effective exchange coupling, the critical
temperature of magnetic phase transition and the adiabatic spin wave spectrum
have been obtained. Different contributions to the free energy of different
phases are estimated. It has been found that the antiferro-ferromagnetic
transition in FeRh occurs mostly due to the spin wave excitations.",0501701v1
2005-10-10,Recent results on energy relaxation in disordered charge and spin density waves,"We briefly review different approaches used recently to describe collective
effects in the strong pinning model of disordered charge and spin density
waves, in connection with the CRTBT very low temperature heat relaxation
experiments.",0510217v1
2005-10-30,Domain instability during precessional magnetization reversal,"Spin wave equations in the non-equilibrium precessing state of a
ferromagnetic system are found. They show a spin-wave instability towards
growing domains of stable magnetization. Precession of the uniform
magnetization mode is described by the Landau Lifshitz equation with the
exponentially growing in time effective Gilbert dissipation constant that could
have both signs. On the developed stages of the domain instability a
non-stationary picture of domain chaos is observed.",0510817v1
2002-08-25,Spinning particles in gravitational wave spacetime,"The dynamics of pseudo-classical spinning particles in spacetime of
gravitational plane waves of general polarization and harmonic profile is
studied. The resulting equations of motion are solved exactly and the results
are compared with those of the other approaches. The relative accelerations of
nearby particles is also calculated.",0208072v1
2005-10-20,Charged particles with spin in a gravitational wave and a uniform magnetic field,"We study the motion of a pseudo-classical charged particle with spin in the
space-time of a gravitational pp wave in the presence of a uniform magnetic
field.",0510094v2
2006-01-13,Symmetric discrete quotients of supersymmetric Hpp-waves and spin structures,"We explore the importance of the choice of spin structure in determining the
amount of supersymmetry preserved by a symmetric M-theory background
constructed by quotienting a supersymmetric Hpp-wave with a discrete subgroup
in the centraliser of its isometry group.",0601087v1
2007-10-01,Next to leading order gravitational wave emission and dynamical evolution of compact binary systems with spin,"Compact binary systems with spinning components are considered. Finite size
effects due to rotational deformation are taken into account. The dynamical
evolution and next to leading order gravitational wave forms are calculated,
taking into account the orbital motion up to the first post-Newtonian
approximation.",0710.0258v2
2009-03-01,Excitonic spin density wave state in iron pnictides,"We examine the appearance of a spin density wave in the FeAs parent compounds
due to an excitonic instability. Using a realistic four-band model, we show
that the magnetic state depends very sensitively upon the details of the band
structure. We demonstrate that an orthorhombic distortion of the crystal
enhances the stability of the antiferromagnetic order.",0903.0124v1
2010-10-13,"Comment on ""Composite excitation of Josephson phase and spin waves in ferromagnetic Josephson junctions"" (S.Hikino, M.Mori, S.Takahashi, and S.Maekawa, arXiv:1009.3551)","We clarify the applicability of the quasistatic approximation used in Ref.
[\onlinecite{VE}], where coupled spin and Josephson plasma waves have been
predicted to exist in SIFS Josephson junctions. We show, contrary to the claim
of the authors of Ref. [\onlinecite{Maekawa}], that this approximation is very
accurate in realistic systems studied experimentally.",1010.2680v1
2020-12-04,Spin Wave Electromagnetic Nonlinear Interaction to Move RF Limiter Frequency Range to Higher Frequencies,"It is shown here that the usual operating frequencies for RF limiters, in the
nominal 5, 11 or 15 GHz center frequencies, can be lifted up into the much
higher frequencies of the 40 to 60 GHz range by a new formula developed from
fundamental spin wave electromagnetic interactions in magnetic material
characterized by a magnetization M.",2012.05687v1
2000-06-19,Dynamic Fano Resonance of Quasienergy Excitons in Superlattices,"The dynamic Fano resonance (DFR) between discrete quasienergy excitons and
sidebands of their ionization continua is predicted and investigated in dc- and
ac-driven semiconductor superlattices. This DFR, well controlled by the ac
field, delocalizes the excitons and opens an intrinsic decay channel in
nonlinear four-wave mixing signals.",0006276v1
2001-07-26,Frequency-dependent rigidity in large-scale interferometric gravitational-wave detectors,"Electromagnetic rigidity which exists in large-scale optical resonators if
pumping frequency is detuned from the eigenfrequency of resonator have
sophisticated spectral dependence which allows to obtain sensitivity better
than the Standard Quantum Limits both for the free test mass and the harmonic
oscillator.",0107084v2
2000-12-25,Propagation and interaction of extremely short electromagnetic pulses in non-linear media,"Propagation of the extremely short electromagnetic pulse in non-linear
dielectric media without the slowly varying envelope approximation is
discussed. The models under consideration take into account both resonant and
not-resonant excitations of non-linear medium, and polarisation states of
electromagnetic wave. Steady state solutions of the relevant equations are
presented for certain of these models.",0012054v1
1998-06-02,Qualitative analysis on the existence of bound excited states and low-lying resonances of the dipositronium,"Symmetry has imposed very strong constraints on the structures of internal
wave functions and on the accessibility of outgoing channels. Based on symmetry
consideration, the existence of a number of bound excited states and low-lying
resonances has been suggested.",9806005v1
2004-04-15,Manipulating the scattering length of a Bose - Einstein condensate in an amplitude - modulated optical lattice,"The scattering length in a BEC confined in an amplitude - modulated optical
lattice can be manipulated by the modulation strength. Two standing laser waves
of main and sideband frequencies of an optical lattice induce a Raman
transition; due to resonant Raman driving the effective scattering length
depends on the modulation strength and the detuning from resonance and can be
tuned to a given value.",0404077v1
2005-06-06,The Sagnac effect in Coupled-Resonator Slow-Light Waveguide Structures,"We study the effect of rotation on the propagation of electromagnetic waves
in slow-light waveguide structures consisting of coupled micro-ring resonators.
We show that such configurations exhibit new a type of the Sagnac effect which
can be used for the realization of highly-compact integrated rotation sensors
and gyroscopes.",0506039v1
1998-07-03,Entanglement Induced Radiation Processes Which are First Order in Weak Field,"Nonlinear processes of light scattering on a two-level system near resonance
are considered. The problem is reduced to the emission and absorption of an
entangled system, formed by a strong resonant field and a two-level system,
having a non-factorizing wave function.",9807011v1
2001-06-13,Relativistic Quantum Theory of Cyclotron Resonance in a Medium,"In this paper the relativistic quantum theory of cyclotron resonance in an
arbitrary medium is presented. The quantum equation of motion for charged
particle in the field of plane electromagnetic wave and uniform magnetic field
in a medium is solved in the eikonal approximation. The probabilities of
induced multiphoton transitions between Landau levels in strong laser field is
calculated.",0106074v1
2005-09-01,Entanglement in resonant photon scattering,"Single--photon which is initially uncorrelated with atom, will evolve to be
entangled with the atom on their continuous kinetic variables in the process of
resonant scattering. We find the relations between the entanglement and their
physical control parameters, which indicates that high entanglement can be
reached by broadening the scale of the atomic wave or squeezing the linewidth
of the incident single--photon pulse.",0509003v2
2006-08-01,Classical search algorithm with resonances in $\sqrt{N}$ cycles,"In this work we use the wave equation to obtain a classical analog of the
quantum search algorithm and we verify that the essence of search algorithms
resides in the establishment of resonances between the initial and the serched
states. In particular we show that, within a set of $N$ vibration modes, it is
possible to excite the searched mode in a number of steps proportional to
$\sqrt N$.",0608019v1
2009-07-22,Spreading of the conception of permanent resonance to wave motions over lattices,"Discovered by us [1] special (permanent) resonance mechanism of spectral zone
creation in periodic structures is generalized to the case of discrete space
lattices and finite difference Schroedinger equation with local V(n) and
minimally nonlocal U(n). It would be interesting to generalize the periodicity
formalism to the multidiagonal finite-difference potentials.",0907.3788v1
2010-01-23,Fano Resonances in High-Tc Superconducting Metamaterial,"We demonstrate a millimeter-wave range metamaterial fabricated from cuprate
superconductor. Two complementary metamaterial structures have been studied,
which exhibit Fano resonances emerging from the collective excitation of
interacting magnetic and electric dipole modes.",1001.4154v1
2010-11-11,Quantized open chaotic systems,"Two different ""wave chaotic"" systems, involving complex eigenvalues or
resonances, can be analyzed using common semiclassical methods. In particular,
one obtains fractal Weyl upper bounds for the density of resonances/eigenvalues
near the real axis, and a classical dynamical criterion for a spectral gap.",1011.2557v2
2012-01-14,Time Delay Plot for Pion-Nucleon Elastic Scattering,"We evaluated the time delay plot in the established region of the Delta(1232)
resonance through the use of elastic scattering phase shift analysis of the
partial wave amplitude P33. The pole position and width of the Delta(1232)
resonance were obtained and found in agreement with earlier calculations.",1201.3044v1
2012-02-07,Resonant laser tunnelling,"We propose an experiment involving a gaussian laser tunneling through a twin
barrier dielectric structure. Of particular interest are the conditions upon
the incident angle for resonance to occur. We provide some numerical
calculations for a particular choice of laser wave length and dielectric
refractive index which confirm our expectations.",1202.1474v1
2013-10-21,Final comment to the results of Bustamante et al. on discrete Rossby/drift wave resonant and quasi-resonant triads,"In this final note we demonstrate that the authors of manuscripts
arXiv:1210.2036, arXiv:1309.0405 and arXiv:1309.5513 use mathematical notations
and notions sometimes in the standard meaning and sometimes in a sense which
differs from the standard. As this specific use is not defined beforehand, the
authors' statements are self-contradictory which makes any further scientific
discussion meaningless.",1310.5625v1
2014-08-04,Quantum statistics of four-wave mixing by a non-linear resonant microcavity,"We analyse the correlation and spectral properties of two-photon states
resonantly transmitted by a non-linear optical microcavity. We trace the
correlation properties of transmitted two-photon states to the decay spectrum
of multi-photon resonances in the non-linear microcavity.",1408.0783v1
2016-02-17,Telegraph equations for the case of a waveguide with moving boundary,"Telegraph equation describing the compression of electromagnetic waves in a
waveguide (resonator) with moving boundary are derived. It is shown that the
character of oscillations of the compressed electromagnetic field depends on
the parameters of the resonator, and under certain conditions, the oscillations
of voltage (current) yield the exponential growth, leading to a noticeable
change in the radiation losses.",1602.05417v1
2021-02-25,Localized structures in dispersive and doubly resonant optical parametric oscillators,"We study temporally localized structures in doubly resonant degenerate
optical parametric oscillators in the absence of temporal walk-off. We focus on
states formed through the locking of domain walls between the zero and a
non-zero continuous wave solution. We show that these states undergo collapsed
snaking and we characterize their dynamics in the parameter space.",2102.12864v1
2021-10-12,Existence of resonances for Schrodinger operators on hyperbolic space,"We prove existence results and lower bounds for the resonances of
Schr\""odinger operators associated to smooth, compactly support potentials on
hyperbolic space. The results are derived from a combination of heat and wave
trace expansions and asymptotics of the scattering phase.",2110.06370v3
2020-07-07,Superradiance by ferroelectrics in cavity resonators,"A theory is presented showing that, under appropriate conditions, a
ferroelectric in a cavity resonator can emit superradiant pulses. Initially,
the ferroelectric has to be prepared in a nonequilibrium state from which it
relaxes emitting a coherent pulse in the infrared region. Polarization dipolar
waves play the role of the triggering mechanism initiating the beginning of the
process.",2007.03300v1
1994-03-11,The hole-hole superconducting pairing in t-J model induced by the long-range spin-wave exchange,"Long-range $(r \sim p_F^{-1} \gg lattice \ spacing)$ spin-wave exchange
produces a very strong pairing of the holes. The different symmetry solutions
of BCS-type equation for the superconducting gap $\Delta$ are found. The most
strong pairing corresponds to $d$-wave symmetry. The physical reasons for the
strong pairing are: 1)large velocity of the spin-wave, 2) a ``collapse'' effect
in the attractive potential (-1/r^2) describing the interaction between two
holes induced by spin-wave exchange. 3)strongly asymmetric hole dispersion. At
concentration of the holes $\delta \sim 0.01-0.3$ we get $\Delta \sim T_c \sim
\epsilon_F$. At very low concentration of the holes the many-body wave function
of the ground state decays into the product of two-hole bound states.",9403045v1
2000-03-29,Role of Phase Variables in Quarter-Filled Spin Density Wave States,"Several kinds of spin density wave (SDW) states with both quarter-filled band
and dimerization are reexamined for a one-dimensional system with on-site,
nearest-neighbor and next-nearest-neighbor repulsive interactions, which has
been investigated by Kobayashi et al. (J. Phys. Soc. Jpn. 67 (1998) 1098).
Within the mean-field theory, the ground state and the response to the density
variation are calculated in terms of phase variables, $\theta$ and $\phi$,
where $\theta$ expresses the charge fluctuation of SDW and $\phi$ describes the
relative motion between density wave with up spin and that with down spin
respectively. It is shown that the exotic state of coexistence of 2k_F-SDW and
2k_F-charge density wave (CDW) is followed by 4k_F-SDW but not by 4k_F-CDW
where k_F denotes a Fermi wave vector. The harmonic potential with respect to
the variation of $\theta$ and/or $\phi$ disappears for the interactions, which
lead to the boundary between the pure 2k_F-SDW state and the corresponding
coexistent state.",0003464v1
1999-10-20,Signature of chaos in gravitational waves from a spinning particle,"A spinning test particle around a Schwarzschild black hole shows a chaotic
behavior, if its spin is larger than a critical value. We discuss whether or
not some peculiar signature of chaos appears in the gravitational waves emitted
from such a system. Calculating the emitted gravitational waves by use of the
quadrupole formula, we find that the energy emission rate of gravitational
waves for a chaotic orbit is about 10 times larger than that for a circular
orbit, but the same enhancement is also obtained by a regular ""elliptic"" orbit.
A chaotic motion is not always enhance the energy emission rate maximally. As
for the energy spectra of the gravitational waves, we find some characteristic
feature for a chaotic orbit. It may tell us how to find out a chaotic behavior
of the system. Such a peculiar behavior, if it will be found, may also provide
us some additional informations to determine parameters of a system such as a
spin.",9910064v1
2003-04-17,Spin Waves as Metric in a Kinetic Space-Time,"1) A wave equation is derived from the kinetic equations governing media with
rotational as well as translational degrees of freedom. In this wave the
fluctuating quantity is a vector, the bulk spin. The transmission is similar to
compressive waves but propagation is possible even in the limit of
incompressibility, where such disturbances could become dominant. 2) In this
context a kinetic theory of space-time is introduced, in which hypothetical
constituents of the space-time manifold possess such a rotational degree of
freedom (spin). Physical fields (i.e. electromagnetic or gravitational) in such
a theory are represented as moments of a statistical distribution of these
constituents. The spin wave equation from 1) is treated as a candidate for
governing light and metric. Such a theory duplicates to first order Maxwell's
equations of electromagnetism, Schrodinger's equation for the electron, and the
Lorentz transformations of special relativity. Slight deviations from the
classical approach are predicted and should be experimentally verifiable.",0304063v5
1997-02-21,New mechanism of collapse and revival in wave packet dynamics due to spin-orbit interaction,"The article discusses the properties of time evolution of wave packets in a
few systems. Dynamics of wave packet motion for Rydberg atoms with the
hierarchy of collapses and revivals is briefly reviewed. The main part of the
paper focuses on the new mechanism of quantum reccurrences in wave packet
dynamics. This mechanism can occur (in principle) in any physical system with
strong enough spin-orbit interaction. We discuss here the SPIN_ORBIT PENDULUM
effect that consists in different motions of subpackets possessing different
spin fields and results in oscillations of a fraction of average angular
momentum between spin and ordinary subspaces. The evolution of localized wave
packet into toroidal objects and backwards (for other class of initial
conditions) is also subject to discussion.",9702044v1
2007-11-15,Electromagnetic wave-particle with spin and magnetic moment,"An axisymmetric static solution of a nonlinear electrodynamics is considered
as a massive charged particle with spin and magnetic moment. A linearization of
the nonlinear electrodynamics around the static solution is investigated. The
appropriate problem for linear waves around the static solution is considered.
This wave part of the particle solution is considered to provide the
appropriate wave properties for the particle. It has been found that the right
(experimentally proved) formula for frequency of this wave appears
theoretically for the static solution with ring singularity.",0711.2499v1
2010-09-07,Critical Correlations for Short-Range Valence-Bond Wave Functions on the Square Lattice,"We investigate the arguably simplest $SU(2)$-invariant wave functions capable
of accounting for spin-liquid behavior, expressed in terms of nearest-neighbor
valence-bond states on the square lattice and characterized by different
topological invariants. While such wave-functions are known to exhibit
short-range spin correlations, we perform Monte Carlo simulations and show that
four-point correlations decay algebraically with an exponent $1.16(4)$. This is
reminiscent of the {\it classical} dimer problem, albeit with a slower decay.
Furthermore, these correlators are found to be spatially modulated according to
a wave-vector related to the topological invariants. We conclude that a
recently proposed spin Hamiltonian that stabilizes the here considered
wave-function(s) as its (degenerate) ground-state(s) should exhibit gapped spin
and gapless non-magnetic excitations.",1009.1307v2
2011-10-19,Spin Waves in 2D ferromagnetic square lattice stripe,"In this work, the area and edges spin wave calculations were carried out
using the Heisenberg Hamiltonian and the tridiagonal method for the 2D
ferromagnetic square lattice stripe, where the SW modes are characterized by a
1D in-plane wave vector $q_x$. The results show a general and an unexpected
feature that the area and edge spin waves only exist as optic modes. This
behavior is also seen in 2D Heisenberg antiferromagnetic square lattice. This
absence of the acoustic modes in the 2D square lattice is explained by the fact
that the geometry constrains for NN exchange inside the square lattice allow
only optical modes. We suggest that this unexpected behavior of spin waves in
the 2D square lattice may be useful in realizing an explanation for HTS.",1110.4369v1
2012-02-15,Self-consistent spin waves in magnetized BEC,"We obtain equations of quantum hydrodynamic (QHD) for magnetized spin-1
neutral Bose-Einstein condensate (BEC). System of QHD equations contains the
equation of magnetic moment evolution (an analog of the Bloch equation). We
account spin-spin interaction along with the short range interaction. We
consider self-consistent field approximation of QHD equations. Starting from
QHD equation we derive the Gross-Pitaevskii equation for magnetized BEC. We
show that Gross-Pitaevskii equation exists under condition that the magnetic
moment direction is not change. Using obtained QHD equations we study the
dispersion of collective excitation. As in electrically polarized BEC [P. A.
Andreev, L. S. Kuz'menkov, arXiv: 1201.2440], in the magnetically polarized BEC
there is second wave mode (polarization mode or spin wave), in addition to the
Bogoliubov's mode. Second wave solution appears due to the magnetic moment
evolution. The influence of magnetization on dispersion of Bogoliubov's mode is
found. We found strong difference of dispersion properties of waves in
magnetized BEC from electrically polarized BEC.",1202.3398v1
2013-05-06,The Pilot-Wave Perspective on Spin,"The alternative pilot-wave theory of quantum phenomena -- associated
especially with Louis de Broglie, David Bohm, and John Bell -- reproduces the
statistical predictions of ordinary quantum mechanics, but without recourse to
special \emph{ad hoc} axioms pertaining to measurement. That (and how) it does
so is relatively straightforward to understand in the case of position
measurements and, more generally, measurements whose outcome is ultimately
registered by the position of a pointer. Despite a widespread belief to the
contrary among physicists, the theory can also account successfully for
phenomena involving spin. The main goal of the paper is to explain how the
pilot-wave theory's account of spin works. Along the way, we provide
illuminating comparisons between the orthodox and pilot-wave accounts of spin
and address some puzzles about how the pilot-wave theory relates to the
important theorems of Kochen and Specker and Bell.",1305.1280v2
2015-04-14,Vestigial chiral and charge orders from bidirectional spin-density waves: Application to the iron-based superconductors,"Recent experiments in optimally hole-doped iron arsenides have revealed a
novel magnetically ordered ground state that preserves tetragonal symmetry,
consistent with either a charge-spin density wave (CSDW), which displays a
non-uniform magnetization, or a spin-vortex crystal (SVC), which displays a
non-collinear magnetization. Here we show that, similarly to the partial
melting of the usual stripe antiferromagnet into a nematic phase, either of
these phases can also melt in two stages. As a result, intermediate
paramagnetic phases with vestigial order appears: a checkerboard charge
density-wave for the CSDW ground state, characterized by an Ising-like order
parameter, and a remarkable spin-vorticity density-wave for the SVC ground
state -- a triplet d-density wave characterized by a vector chiral order
parameter. We propose experimentally detectable signatures of these phases,
show that their fluctuations can enhance the superconducting transition
temperature, and discuss their relevance to other correlated materials.",1504.03656v3
2015-05-04,Composite spin and quadrupole wave in the ordered phase of Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$,"The hidden ordered state of the frustrated pyrochlore oxide
Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$ is possibly one of the two electric multipolar,
or quadrupolar, states of the effective pseudospin-1/2 Hamiltonian derived from
crystal-field ground state doublets of non-Kramers Tb$^{3+}$ ions. These
long-range orders are antiparallel or parallel alignments of transverse
pseudospin components representing electric quadrupole moments, which cannot be
observed as magnetic Bragg reflections by neutron scattering. However
pseudospin waves of these states are composite waves of the magnetic-dipole and
electric-quadrupole moments, and can be partly observed by inelastic magnetic
neutron scattering. We calculate these spin-quadrupole waves using linear
spin-wave theory and discuss previously observed low-energy magnetic excitation
spectra of a polycrystalline sample with $x = 0.005$ ($T_{\text{c}} = 0.5 $ K).",1505.00503v5
2015-09-03,Spin effects in Kapitza-Dirac scattering at light with elliptical polarization,"The Kapitza-Dirac effect, which refers to electron scattering at standing
light waves, is studied in the Bragg regime with counterpropagating
elliptically polarized electromagnetic waves with the same intensity,
wavelength, and degree of polarization for two different setups. In the first
setup, where the electric-field components of the counterpropagating waves have
the same sense of rotation, we find distinct spin effects. The spins of the
scattered electrons and of the nonscattered electrons, respectively, precess
with a frequency that is of the order of the Bragg-reflection Rabi frequency.
When the electric-field components of the counterpropagating waves have an
opposite sense of rotation, which is the second considered setup, the standing
wave has linear polarization, and no spin effects can be observed. Our results
are based on numerical solutions of the time-dependent Dirac equation and the
analytical solution of a relativistic Pauli equation, which accounts for the
leading relativistic effects.",1509.01150v2
2016-02-24,Exchange stiffness in ultrathin perpendicularly-magnetized CoFeB layers determined using spin wave spectroscopy,"We measure the frequencies of spin waves in nm-thick perpendicularly
magnetized FeCoB systems, and model the frequencies to deduce the exchange
stiffness of this material in the ultrathin limit. For this, we embody the
layers in magnetic tunnel junctions patterned into circular nanopillars of
diameters ranging from 100 to 300 nm and we use magneto-resistance to determine
which rf-current frequencies are efficient in populating the spin wave modes.
Micromagnetic calculations indicate that the ultrathin nature of the layer and
the large wave vectors used ensure that the spin wave frequencies are
predominantly determined by the exchange stiffness, such that the number of
modes in a given frequency window can be used to estimate the exchange. For 1
nm layers the experimental data are consistent with an exchange stiffness A= 20
pJ/m, which is slightly lower that its bulk counterpart. The thickness
dependence of the exchange stiffness has strong implications for the numerous
situations that involve ultrathin films hosting strong magnetization gradients,
and the micromagnetic description thereof.",1602.07421v1
2016-09-23,Spin waves in rings of classical magnetic dipoles,"We theoretically and numerically investigate spin waves that occur in systems
of classical magnetic dipoles that are arranged at the vertices of a regular
polygon and interact solely via their magnetic fields. There are certain
limiting cases that can be analyzed in detail. One case is that of spin waves
as infinitesimal excitations from the system's ground state, where the
dispersion relation can be determined analytically. The frequencies of these
infinitesimal spin waves are compared with the peaks of the Fourier transform
of the thermal expectation value of the autocorrelation function calculated by
Monte Carlo simulations. In the special case of vanishing wave number an exact
solution of the equations of motion is possible describing synchronized
oscillations with finite amplitudes. Finally, the limiting case of a dipole
chain with $N\longrightarrow \infty$ is investigated and completely solved.",1609.07264v2
2012-09-17,Nonlinear emission of spin-wave caustics from an edge mode of a micro-structured Co2Mn0.6Fe0.4Si waveguide,"Magnetic Heusler materials with very low Gilbert damping are expected to show
novel magnonic transport phenomena. We report nonlinear generation of higher
harmonics leading to the emission of caustic spin-wave beams in a low-damping,
micro-structured Co2Mn0.6Fe0.4Si Heusler waveguide. The source for the higher
harmonic generation is a localized edge mode formed by the strongly
inhomogeneous field distribution at the edges of the spin-wave waveguide. The
radiation characteristics of the propagating caustic waves observed at twice
and three times the excitation frequency are described by an analytical
calculation based on the anisotropic dispersion of spin waves in a magnetic
thin film.",1209.3669v2
2018-02-01,Theory of spin and lattice wave dynamics excited by focused laser pulses,"We develop a theory of the spin wave dynamics excited by ultrafast focused
laser pulses in a magnetic film. We take into account both volume and surface
spin wave modes in the presence of applied, dipolar and magnetic anisotropy
fields and include the dependence on laser spot exposure size and magnetic
damping. We show that the sound waves generated by local heating by an
ultrafast focused laser pulse can excite a wide spectrum of spin waves (on top
of a dominant magnon-phonon contribution). Good agreement with recent
experiments supports the validity of the model.",1802.00178v2
2020-08-10,Evidence of pair-density wave in doping Kitaev spin liquid on the honeycomb lattice,"We study the effects of doping the Kitaev model on the honeycomb lattice
where the spins interact via the bond-directional interaction $J_K$, which is
known to have a quantum spin liquid as its exact ground state. The effect of
hole doping is studied within the $t$-$J_K$ model on a three-leg cylinder using
density-matrix renormalization group. Upon light doping, we find that the
ground state of the system has quasi-long-range charge-density-wave
correlations but short-range single-particle correlations. The dominant pairing
channel is the even-parity superconducting pair-pair correlations with
$d$-wave-like symmetry, which oscillate in sign as a function of separation
with a period equal to that of the spin-density wave and two times the
charge-density wave. Although these correlations fall rapidly (possibly
exponentially) at long distances, this is never-the-less the first example
where a pair-density wave is the strongest SC order on a bipartite lattice. Our
results may be relevant to ${\rm Na_2IrO_3}$ and $\alpha$-${\rm RuCl_3}$ upon
doping.",2008.03858v1
2004-05-05,Spin waves in a Bose Ferromagnet,"It is shown that the ferromagnetic transition takes place always above
Bose-Einstein condensation in ferromagnetically coupled spinor Bose gases. We
describe the Bose ferromagnet within Ginzburg-Landau theory by a ""two-fluid""
model below Bose-Einstein condensation. Both the Bose condensate and the normal
phase are spontaneously magnetized. As a main result we show that spin waves in
the two fluids are coupled together so as to produce only one mixed spin-wave
mode in the coexisting state. The long wavelength spectrum is quadratic in the
wave vector ${\bf k}$, consistent with usual ferromagnetism theory, and the
spin-wave stiffness coefficient $c_s$ includes contributions from both the two
phases, implying the ""two-fluid"" feature of the system. $c_s$ can show a sharp
bend at the Bose-Einstein condensation temperature.",0405094v1
2017-03-16,All-Angle Collimation for Spin Waves,"We studied the effect of collimation for monochromatic beams of spin waves,
resulting from the refraction at the interface separating two magnetic
half-planes. The collimation was observed in broad range of the angles of
ncidence for homogenous Co and Py half-planes, due to significant intrinsic
anisotropy of spin wave propagation in these materials. The effect exists for
the sample saturated by in plane magnetic field tangential to the interface.
The collimation for all possible angles of incidence was found in the system
where the incident spin wave is refracted on the interface between homogeneous
and periodically patterned layers of YIG. The refraction was investigated by
the analysis of isofrequency dispersion contours of both pairs materials, i.e.,
uniform YIG/patterned YIG and Co/Py, which are calculated with the aid of the
plane wave method. Besides, the refraction in Co/Py system was studied using
micromagnetic simulations.",1703.05548v1
2019-10-25,Twisted magnon as a magnetic tweezer,"Wave fields with spiral phase dislocations carrying orbital angular momentum
(OAM) have been realized in many branches of physics, such as for photons,
sound waves, electron beams, and neutrons. However, the OAM states of magnons
(spin waves)$-$the building block of modern magnetism$-$and particularly their
implications have yet to be addressed. Here, we theoretically investigate the
twisted spin-wave generation and propagation in magnetic nanocylinders. The OAM
nature of magnons is uncovered by showing that the spin-wave eigenmode is also
the eigenstate of the OAM operator in the confined geometry. Inspired by
optical tweezers, we predict an exotic ""magnetic tweezer"" effect by showing
skyrmion gyrations under twisted magnons in exchange coupled
nanocylinder$|$nanodisk heterostructure, as a practical demonstration of
magnonic OAM to manipulate topological spin defects. Our study paves the way
for the emerging magnetic manipulations by harnessing the OAM degree of freedom
of magnons.",1910.11528v2
2021-01-28,Néel domain wall as a tunable filter for optically excited magnetostatic waves,"We present a concept of a tunable optical excitation of spin waves and
filtering their spectra in a ferromagnetic film with 180$^{\circ}$ N\'eel
domain wall. We show by means of micromagnetic simulation that the fluence of
the femtosecond laser pulse and its position with respect to the domain wall
affect the frequencies of the excited spin waves, and the presence of the
domain wall plays crucial role in control of the spin waves' spectrum. The
predicted effects are understood by analyzing the changes of the spin waves'
dispersion under the impact of the laser pulse.",2101.11931v3
2022-11-10,High wave vector non-reciprocal spin wave beams,"We report unidirectional transmission of micron-wide spin waves beams in a 55
nm thin YIG. We downscaled a chiral coupling technique implementing Ni80Fe20
nanowires arrays with different widths and lattice spacing to study the
non-reciprocal transmission of exchange spin waves down to lambda = 80 nm. A
full spin wave spectroscopy analysis of these high wavevector coupled-modes
shows some difficulties to characterize their propagation properties, due to
both the non-monotonous field dependence of the coupling efficiency, and also
the inhomogeneous stray field from the nanowires.",2211.05514v2
2023-04-11,Sensitive detection of millimeter wave electric field by driving trapped surface-state electrons,"Sensitive detection of electromagnetic wave electric field plays an important
role for electromagnetic communication and sensing. Here, we propose a quantum
sensor to sensitively detect the electric field of the millimeter (mm) wave.
The quantum sensor consists of many surface-state electrons trapped
individually on liquid helium by a scalable electrode-network at the bottom of
the helium film. On such a chip, each of the trapped electrons can be
manipulated by the biased dc-current to deliver the strong spin-orbit
couplings. The mm wave signal to be detected is applied to non-dispersively
drive the orbital states of the trapped electrons, just resulting in the Stark
shifts of the dressed spin-orbital states. As a consequence, the electric field
of the applied mm wave could be detected sensitively by using the spin-echo
interferometry of the long-lived spin states of the electrons trapped on liquid
helium. The reasonable accuracy of the detection and also the feasibility of
the proposal are discussed.",2304.05154v1
2023-06-09,Ordering in SU(4)-symmetric model of AA bilayer graphene,"We examine possible ordered states of AA stacked bilayer graphene arising due
to electron-electron coupling. We show that under certain assumptions the
Hamiltonian of the system possesses an SU(4) symmetry. The multicomponent order
parameter is described by a $4\times4$ matrix $\hat{Q}$, for which a mean-field
self-consistency equation is derived. This equation allows Hermitian and
non-Hermitian solutions. Hermitian solutions can be grouped into three
topologically-distinct classes. First class corresponds to the charge density
wave. Second class includes spin density wave, valley density wave, and
spin-valley density wave. An ordered state in the third class is a combination
of all the aforementioned density-wave types. For anti-Hermitian $\hat{Q}$ the
ordered states are characterized by spontaneous inter-layer loop currents
flowing in the bilayer. Depending on the topological class of the solution
these currents can carry charge, spin, valley, and spin-valley quanta. We also
discuss the special case when matrix $\hat{Q}$ is not Hermitian and not
anti-Hermitian. Utility and weak points of the proposed SU(4)-based
classification scheme of the ordered states are analyzed.",2306.05796v2
2023-06-28,Chern insulating state with double-$Q$ ordering wave vectors at the Brillouin zone boundary,"Magnetic multiple-$Q$ states consisting of multiple spin density waves are a
source of unconventional topological spin textures, such as skyrmion and
hedgehog. We theoretically investigate a topologically nontrivial double-$Q$
state with a net spin scalar chirality on a two-dimensional square lattice. We
find that a double-$Q$ spiral superposition of the ordering wave vectors
located at the Brillouin zone boundary gives rise to unconventional noncoplanar
spin textures distinct from the skyrmion crystal. We show that such a
double-$Q$ state is stabilized by the interplay among the easy-axis anisotropic
interaction, high-harmonic wave-vector interaction, and external magnetic
field. Furthermore, the obtained double-$Q$ state becomes a Chern insulating
state with a quantum Hall conductivity when the Fermi level is located in the
band gaps. Our present results provide another platform to realize topological
magnetic states other than skyrmion crystals by focusing on the symmetry of
constituent ordering wave vectors in momentum space.",2306.15854v1
2008-04-17,"A study of the quantum classical crossover in the spin dynamics of the 2D S=5/2 antiferromagnet Rb2MnF4: neutron scattering, computer simulations, and analytic theories","We report comprehensive inelastic neutron scattering measurements of the
magnetic excitations in the 2D spin-5/2 Heisenberg antiferromagnet Rb2MnF4 as a
function of temperature from deep in the Neel ordered phase up to paramagnetic,
0.13 < kBT/4JS < 1.4. Well defined spin-waves are found for wave-vectors larger
than the inverse correlation length $\eta^{-1}$ for temperatures up to near the
Curie-Weiss temperature, $\Theta_{CW}$. For wave-vectors smaller than
$\eta^{-1}$, relaxational dynamics occurs. The observed renormalization of
spin-wave energies, and evolution of excitation line-shapes, with increasing
temperature are quantitatively compared with finite-temperature spin-wave
theory, and computer simulations for classical spins. Random phase
approximation calculations provide a good description of the low-temperature
renormalisation of spin-waves. In contrast, lifetime broadening calculated
using the first Born approximation shows, at best, modest agreement around the
zone boundary at low temperatures. Classical dynamics simulations using an
appropriate quantum-classical correspondence were found to provide a good
description of the intermediate- and high-temperature regimes over all
wave-vector and energy scales, and the crossover from quantum to classical
dynamics observed around $\Theta_{CW}/S$, where the spin S=5/2. A
characterisation of the data over the whole wave-vector/energy/temperature
parameter space is given. In this, $T^2$ behaviour is found to dominate the
wave-vector and temperature dependence of the line widths over a large
parameter range, and no evidence of hydrodynamic behaviour or dynamical scaling
behaviour found within the accuracy of the data sets.",0804.2901v2
2001-01-05,"Comment on ""Gravity Waves, Chaos, and Spinning Compact Binaries""","In this comment, I argue that chaotic effects in binary black hole inspiral
will not strongly impact the detection of gravitational waves from such
systems.",0101024v1
2009-09-23,Wave-particle duality and the Hamilton action,"The Hamilton-Jacobi equation of relativistic quantum mechanics is revisited.
The equation is shown to permit solutions in the form of breathers
(oscillating/spinning solitons), displaying simultaneous particle-like and
wave-like behaviour.",0909.4195v1
2014-10-21,Electromagnetic space-time crystals. III. Dispersion relations for partial solutions,"Partial solutions of the Dirac equation describing an electron motion in
electromagnetic crystals created by plane waves with linear and circular
polarizations are treated. It is shown that the electromagnetic crystal formed
by circularly polarized waves possesses the spin birefringence.",1410.5536v1
2017-07-01,Intrinsic translational symmetry breaking in a doped Mott insulator,"A central issue of Mott physics, with symmetries being fully retained in the
spin background, concerns the charge excitation. In a two-leg spin ladder with
spin gap, an injected hole can exhibit either a Bloch wave or a density wave by
tuning the ladder anisotropy through a `quantum critical point' (QCP). The
nature of such a QCP has been a subject of recent studies by density matrix
renormalization group (DMRG). In this paper, we reexamine the ground state of
the one doped hole, and show that a two-component structure is present in the
density wave regime in contrast to the single component in the Bloch wave
regime. In the former, the density wave itself is still contributed by a
standing-wave-like component characterized by a quasiparticle spectral weight
$Z$ in a finite-size system. But there is an additional charge incoherent
component emerging, which intrinsically breaks the translational symmetry
associated with the density wave. The partial momentum is carried away by
neutral spin excitations. Such an incoherent part does not manifest in the
single-particle spectral function, directly probed by the angle-resolved
photoemission spectroscopy (ARPES) measurement, however it is demonstrated in
the momentum distribution function. The Landau's one-to-one correspondence
hypothesis for a Fermi liquid breaks down here. The microscopic origin of this
density wave state as an intrinsic manifestation of the doped Mott physics will
be also discussed.",1707.00068v2
2005-01-05,Post-Newtonian accurate parametric solution to the dynamics of spinning compact binaries in eccentric orbits: The leading order spin-orbit interaction,"We derive Keplerian-type parametrization for the solution of post-Newtonian
(PN) accurate conservative dynamics of spinning compact binaries moving in
eccentric orbits. The PN accurate dynamics that we consider consists of the
third post-Newtonian accurate conservative orbital dynamics influenced by the
leading order spin effects, namely the leading order spin-orbit interactions.
The orbital elements of the representation are explicitly given in terms of the
conserved orbital energy, angular momentum and a quantity that characterizes
the leading order spin-orbit interactions in Arnowitt, Deser, and Misner-type
coordinates. Our parametric solution is applicable in the following two
distinct cases: (i) the binary consists of equal mass compact objects, having
two arbitrary spins, and (ii) the binary consists of compact objects of
arbitrary mass, where only one of them is spinning with an arbitrary spin. As
an application of our parametrization, we present gravitational wave
polarizations, whose amplitudes are restricted to the leading quadrupolar
order, suitable to describe gravitational radiation from spinning compact
binaries moving in eccentric orbits. The present parametrization will be
required to construct `ready to use' reference templates for gravitational
waves from spinning compact binaries in inspiralling eccentric orbits. Our
parametric solution for the post-Newtonian accurate conservative dynamics of
spinning compact binaries clearly indicates, for the cases considered, the
absence of chaos in these systems. Finally, we note that our parametrization
provides the first step in deriving a fully second post-Newtonian accurate
`timing formula', that may be useful for the radio observations of relativistic
binary pulsars like J0737-3039.",0501011v1
2008-04-02,Spin-stiffness of anisotropic Heisenberg model on square lattice and possible mechanism for pinning of the electronic liquid crystal direction in YBCO,"Using series expansions and spin-wave theory we calculate the spin-stiffness
anisotropy $\rho_{sx}/\rho_{sy}$ in Heisenberg models on the square lattice
with anisotropic couplings $J_x,J_y$. We find that for the weakly anisotropic
spin-half model ($J_x\approx J_y$), $\rho_{sx}/\rho_{sy}$ deviates
substantially from the naive estimate $\rho_{sx}/\rho_{sy} \approx J_x/J_y$. We
argue that this deviation can be responsible for pinning the electronic liquid
crystal direction, a novel effect recently discovered in YBCO. For
completeness, we also study the spin-stiffness for arbitrary anisotropy
$J_x/J_y$ for spin-half and spin-one models. In the limit of $J_y/J_x\to 0$,
when the model reduces to weakly coupled chains, the two show dramatically
different behavior. In the spin-one model, the stiffness along the chains goes
to zero, implying the onset of Haldane-gap phase, whereas for spin-half the
stiffness along the chains increases monotonically from a value of $0.18 J_x$
for $J_y/J_x=1$ towards $0.25 J_x$ for $J_y/J_x\to 0$. Spin-wave theory is
extremely accurate for spin-one but breaks down for spin-half presumably due to
the onset of topological terms.",0804.0400v1
2008-08-12,Renormalized 2PN spin contributions to the accumulated orbital phase for LISA sources,"We give here a new third post-Newtonisn (3PN) spin-spin contribution (in the
PN parameter $\epsilon $) to the accumulated orbital phase of a compact binary,
arising from the spin-orbit precessional motion of the spins. In the equal mass
case this contribution vanishes, but LISA sources of merging supermassive
binary black holes have typically a mass ratio of 1:10. For such non-equal
masses this 3PN correction is periodic in time, with period approximately
$\epsilon ^{-1}$ times larger than the period of gravitational waves. We derive
a renormalized and simpler expression of the spin-spin coefficient at 2PN, as
an average over the time-scale of this period of the combined 2PN and 3PN
contribution. We also find that for LISA sources the quadrupole-monopole
contribution to the phase dominates over the spin-spin contribution, while the
self-spin contribution is negligible even for the dominant spin. Finally we
define a renormalized total spin coefficient $\bar{\sigma}$ to be employed in
the search for gravitational waves emitted by LISA sources.",0808.1704v2
2019-06-12,Binary neutron star mergers: Effects of spin and post-merger dynamics,"Spin can have significant effects on the electromagnetic transients
accompanying binary neutron star mergers. The measurement of spin can provide
important information about binary formation channels. In the absence of a
strong neutron star spin prior, the degeneracy of spin with other parameters
leads to significant uncertainties in their estimation, in particular limiting
the power of gravitational waves to place tight constraints on the nuclear
equation of state. Thus detailed studies of highly spinning neutron star
mergers are essential to understand all aspects of multimessenger observation
of such events. We perform a systematic investigation of the impact of neutron
star spin---considering dimensionless spin values up to $a_{\rm NS}=0.33$---on
the merger of equal mass, quasicircular binary neutron stars using fully
general-relativistic simulations. We find that the peak frequency of the
post-merger gravitational wave signal is only weakly influenced by the neutron
star spin, with cases where the spin is aligned (antialigned) with the orbital
angular momentum giving slightly lower (higher) values compared to the
irrotational case. We find that the one-arm instability arises in a number of
cases, with some dependence on spin. Spin has a pronounced impact on the mass,
velocity, and angular distribution of the dynamical ejecta, and the mass of the
disk that remains outside the merger remnant. We discuss the implications of
these findings on anticipated electromagnetic signals, and on constraints that
have been placed on the equation of state based on multimessenger observations
of GW170817.",1906.05288v2
2016-03-08,Searching for Gravitational Waves from Compact Binaries with Precessing Spins,"Current searches for gravitational waves from compact-object binaries with
the LIGO and Virgo observatories employ waveform models with spins aligned (or
anti-aligned) with the orbital angular momentum. Here, we derive a new
statistic to search for compact objects carrying generic (precessing) spins.
Applying this statistic, we construct banks of both aligned- and generic-spin
templates for binary black holes and neutron-star--black-hole binaries, and
compare the effectualness of these banks towards simulated populations of
generic-spin systems. We then use these banks in a pipeline analysis of
Gaussian noise to measure the increase in background incurred by using generic-
instead of aligned-spin banks. Although the generic-spin banks have a factor of
ten to twenty more templates than the aligned-spin banks, we find an overall
improvement in signal recovery at fixed false-alarm rate for systems with
high-mass ratio and highly precessing spins ---up to 60\% for
neutron-star--black-hole mergers. This gain in sensitivity comes at a small
loss of sensitivity ($\lesssim$4\%) for systems that are already well-covered
by aligned-spin templates. Since the observation of even a single binary merger
with misalinged spins could provide unique astrophysical insights into the
formation of these sources, we recommend that the method described here be
developed further to mount a viable search for generic-spin binary mergers in
LIGO/Virgo data.",1603.02444v2
2017-06-23,Ferroic collinear multilayer magnon spin valve,"Information transport and processing by pure magnonic spin currents in
insulators is a promising alternative to conventional charge-current driven
spintronic devices. The absence of Joule heating as well as the reduced spin
wave damping in insulating ferromagnets has been suggested to enable the
implementation of efficient logic devices. After the proof of concept for a
logic majority gate based on the superposition of spin waves has been
successfully demonstrated, further components are required to perform complex
logic operations. A key component is a switch that corresponds to a
conventional magnetoresistive spin valve. Here, we report on magnetization
orientation dependent spin signal detection in collinear magnetic multilayers
with spin transport by magnonic spin currents. We find in Y3Fe5O12|CoO|Co
tri-layers that the detected spin signal depends on the relative alignment of
Y3Fe5O12 and Co. This demonstrates a spin valve behavior with an effect
amplitude of 120% in our systems. We demonstrate the reliability of the effect
and investigate the origin by both temperature and power dependent
measurements, showing that spin rectification effects and a magnetic layer
alignment dependent spin transport effect result in the measured signal.",1706.07592v1
2022-04-22,Inducing spin-order with an impurity: phase diagram of the magnetic Bose polaron,"We investigate the formation of magnetic Bose polaron, an impurity atom
dressed by spin-wave excitations, in a one-dimensional spinor Bose gas. In
terms of an effective potential model the impurity is strongly confined by the
host excitations which can even overcome the impurity-medium repulsion leading
to a self-localized quasi-particle state. The phase diagram of the attractive
and self-bound repulsive magnetic polaron, repulsive non-magnetic (Fr{\""
o}hlich-type) polaron and impurity-medium phase-separation regimes is explored
with respect to the Rabi-coupling between the spin components, spin-spin
interactions and impurity-medium coupling. The residue of such magnetic
polarons decreases substantially in both strong attractive and repulsive
branches with strong impurity-spin interactions, illustrating significant
dressing of the impurity. The impurity can be used to probe and maneuver the
spin polarization of the magnetic medium while suppressing ferromagnetic
spin-spin correlations. It is shown that mean-field theory fails as the spinor
gas approaches immiscibility since the generated spin-wave excitations are
prominent. Our findings illustrate that impurities can be utilized to generate
controllable spin-spin correlations and magnetic polaron states which can be
realized with current cold atom setups.",2204.10960v1
2022-08-04,Numerical-relativity surrogate modeling with nearly extremal black-hole spins,"Numerical relativity (NR) simulations of binary black hole (BBH) systems
provide the most accurate gravitational wave predictions, but at a high
computational cost -- especially when the black holes have nearly extremal
spins (i.e. spins near the theoretical upper limit) or very unequal masses.
Recently, the technique of Reduced Order Modeling (ROM) has enabled the
construction of surrogate models trained on an existing set of NR waveforms.
Surrogate models enable the rapid computation of the gravitational waves
emitted by BBHs. Typically these models are used for interpolation to compute
gravitational waveforms for BBHs with mass ratios and spins within the bounds
of the training set. Because simulations with nearly extremal spins are so
technically challenging, surrogate models almost always rely on training sets
with only moderate spins. In this paper, we explore how well surrogate models
can extrapolate to nearly extremal spins when the training set only includes
moderate spins. For simplicity, we focus on one-dimensional surrogate models
trained on NR simulations of BBHs with equal masses and equal, aligned spins.
We assess the performance of the surrogate models at higher spin magnitudes by
calculating the mismatches between extrapolated surrogate model waveforms and
NR waveforms, by calculating the differences between extrapolated and NR
measurements of the remnant black-hole mass, and by testing how the surrogate
model improves as the training set extends to higher spins. We find that while
extrapolation in this one-dimensional case is viable for current detector
sensitivities, surrogate models for next-generation detectors should use
training sets that extend to nearly extremal spins.",2208.02927v1
2000-07-11,"Classifying Reported and ""Missing"" Resonances According to Their P and C Properties","The Hilbert space H^3q of the three quarks with one excited quark is
decomposed into Lorentz group representations. It is shown that the quantum
numbers of the reported and ``missing'' resonances fall apart and populate
distinct representations that differ by their parity or/and charge conjugation
properties. In this way, reported and ``missing'' resonances become
distinguishable. For example, resonances from the full listing reported by the
Particle Data Group are accommodated by Rarita-Schwinger (RS) type
representations (k/2,k/2)*[(1/2,0)+(0,1/2)] with k=1,3, and 5, the highest spin
states being J=3/2^-, 7/2^+, and 11/2^+, respectively. In contrast to this,
most of the ``missing'' resonances fall into the opposite parity RS fields of
highest-spins 5/2^-, 5/2^+, and 9/2^+, respectively. Rarita-Schwinger fields
with physical resonances as lower-spin components can be treated as a whole
without imposing auxiliary conditions on them. Such fields do not suffer the
Velo-Zwanziger problem but propagate causally in the presence of
electromagnetic fields. The pathologies associated with RS fields arise
basically because of the attempt to use them to describe isolated spin-J=k+1/ 2
states, rather than multispin-parity clusters. The positions of the observed RS
clusters and their spacing are well explained trough the interplay between the
rotational-like (k/2)(k/2 +1)-rule and a Balmer-like -(k+1)^{-2}-behavior.",0007022v1
2012-06-26,Resonant Compton Upscattering in High Field Neutron Stars,"The extremely efficient process of resonant Compton upscattering by
relativistic electrons in high magnetic fields is believed to be a leading
emission mechanism of high field pulsars and magnetars in the production of
intense X-ray radiation. New analytic developments for the Compton scattering
cross section using Sokolov & Ternov (S&T) states with spin-dependent resonant
widths are presented. These new results display significant numerical
departures from both the traditional cross section using spin-averaged widths,
and also from the spin-dependent cross section that employs the Johnson &
Lippmann (J&L) basis states, thereby motivating the astrophysical deployment of
this updated resonant Compton formulation. Useful approximate analytic forms
for the cross section in the cyclotron resonance are developed for S&T basis
states. These calculations are applied to an inner magnetospheric model of the
hard X-ray spectral tails in magnetars, recently detected by RXTE and INTEGRAL.
Relativistic electrons cool rapidly near the stellar surface in the presence of
intense baths of thermal X-ray photons. We present resonant Compton cooling
rates for electrons, and the resulting photon spectra at various magnetospheric
locales, for magnetic fields above the quantum critical value. These
demonstrate how this scattering mechanism has the potential to produce the
characteristically flat spectral tails observed in magnetars.",1206.5957v1
2013-01-21,"Interatomic potentials, electric properties, and spectroscopy of the ground and excited states of the Rb_2 molecule: Ab initio calculations and effect of a non-resonant field","We formulate the theory for a diatomic molecule in a spatially degenerate
electronic state interacting with a non-resonant laser field and investigate
its rovibrational structure in the presence of the field. We report on
\textit{ab initio} calculations employing the double electron attachment
intermediate Hamiltonian Fock space coupled cluster method restricted to single
and double excitations for all electronic states of the Rb$_2$ molecule up to
$5s+5d$ dissociation limit of about 26.000$\,$cm$^{-1}$. In order to correctly
predict the spectroscopic behavior of Rb$_2$, we have also calculated the
electric transition dipole moments, non-adiabatic coupling and spin-orbit
coupling matrix elements, and static dipole polarizabilities, using the
multireference configuration interaction method. When a molecule is exposed to
strong non-resonant light, its rovibrational levels get hybridized. We study
the spectroscopic signatures of this effect for transitions between the
X$^1\Sigma_g^+$ electronic ground state and the A$^1\Sigma_u^+$ and b$^3\Pi_u$
excited state manifold. The latter is characterized by strong perturbations due
to the spin-orbit interaction. We find that for non-resonant field strengths of
the order $10^9$W/cm$^2$, the spin-orbit interaction and coupling to the
non-resonant field become comparable. The non-resonant field can then be used
to control the singlet-triplet character of a rovibrational level.",1301.4966v2
2023-01-10,"Variable bandwidth, high efficiency microwave resonator for control of spin-qubits in nitrogen-vacancy centers","Nitrogen-Vacancy (NV) centers in diamond are attractive tools for sensing and
quantum information. Realization of this potential requires effective tools for
controlling the spin degree of freedom by microwave (mw) magnetic fields. In
this work we present a planar microwave resonator optimized for
microwave-optical double resonance experiments on single nitrogen-vacancy (NV)
centers in diamond. It consists of a piece of wide microstrip line which is
symmetrically connected to two 50 $\Omega$ microstrip feed lines. In the center
of the resonator, an $\Omega$-shaped loop focuses the current and the mw
magnetic field. It generates a relatively homogeneous magnetic field over a
volume of 0.07mm$^2\times$0.1mm. It can be operated at 2.9 GHz in both
transmission and reflection modes with bandwidths of 1000 MHz and 400 MHz,
respectively. The high power-to-magnetic field conversion efficiency allows to
produce $\pi$-pulses with a duration of 50 ns with only about 200 mW and 50 mW
microwave power in transmission and reflection, respectively. The transmission
mode also offers capability for efficient radio frequency excitation. The
resonance frequency can be tuned between 1.3 GHz and 6 GHz by adjusting the
length of the resonator. This will be useful for experiments on NV-centers at
higher external magnetic fields and on different types of optically active spin
centers.",2301.03911v2
1999-10-21,Effective action and collective modes in quasi-one-dimensional spin-density-wave systems,"We derive the effective action describing the long-wavelength low-energy
collective modes of quasi-one-dimensional spin-density-wave (SDW) systems,
starting from the Hubbard model within weak coupling approximation. The
effective action for the spin-wave mode corresponds to an anisotropic
non-linear sigma model together with a Berry phase term. We compute the spin
stiffness and the spin-wave velocity. We also obtain the effective action for
the sliding mode (phason) taking into account the density fluctuations from the
outset and in presence of a weak external electromagnetic field. This leads to
coupled equations for the phase of the SDW condensate and the charge density
fluctuations. We also calculate the conductivity and the density-density
correlation function.",9910343v2
2005-02-09,Weak ferromagnetism and spiral spin structures in honeycomb Hubbard planes,"Within the Hartree Fock- RPA analysis, we derive the spin wave spectrum for
the weak ferromagnetic phase of the Hubbard model on the honeycomb lattice.
Assuming a uniform magnetization, the polar (optical) and acoustic branches of
the spin wave excitations are determined. The bipartite lattice geometry
produces a q-dependent phase difference between the spin wave amplitudes on the
two sub-lattices. We also find an instability of the uniform weakly magnetized
configuration to a weak antiferromagnetic spiraling spin structure, in the
lattice plane, with wave vector Q along the Gamma-K direction, for electron
densities n>0.6. We discuss the effect of diagonal disorder on both the
creation of electron bound states, enhancement of the density of states, and
the possible relevance of these effects to disorder induced ferromagnetism, as
observed in proton irradiated graphite.",0502249v2
2006-01-20,Spin Structure Factor of the Frustrated Quantum Magnet Cs_2CuCl_4,"The ground state properties and neutron structure factor for the
two-dimensional antiferromagnet on the triangular lattice, with uni-directional
anisotropy in the nearest-neighbor exchange couplings and a weak
Dzyaloshinskii-Moriya (DM) interaction, are studied. This Hamiltonian has been
used to interpret neutron scattering measurements on the spin 1/2 spiral
spin-density-wave system, Cs_2CuCl_4, [R. Coldea, et al., Phys. Rev. B 68,
134424 (2003)]. Calculations are performed using a 1/S expansion, taking into
account interactions between spin-waves. The ground state energy, the shift of
the ordering wave-vector, Q, and the local magnetization are all calculated to
order 1/S^2. The neutron structure factor, obtained using anharmonic spin-wave
Green's functions to order 1/S, is shown to be in reasonable agreement with
published neutron data, provided that slightly different parameters are used
for the exchange and DM interactions than those inferred from measurements in
high magnetic field.",0601486v1
2006-09-04,Magnetization reversal and nonexponential relaxation via instabilities of internal spin waves in nanomagnets,"A magnetic particle with atomic spins ordered in an unstable direction is an
example of a false vacuum that decays via excitation of internal spin waves.
Coupled evolution of the particle's magnetization (or the vacuum state) and
spin waves, considered in the time-dependent vacuum frame, leads to a peculiar
relaxation that is very fast at the beginning but slows down to a
nonexponential long tail at the end. The two main scenarios are linear and
exponential spin-wave instabilities. For the former, the longitudinal and
transverse relaxation rates have been obtained analytically. Numerical
simulations show that the particle's magnetization strongly decreases in the
middle of reversal and then recovers.",0609074v2
2007-09-04,Soft Spin Wave Near nu=1: Evidence for a Magnetic Instability in Skyrmion Systems,"The ground state of the two dimensional electron gas near $\nu$=1 is
investigated by inelastic light scattering measurements carried down to very
low temperatures. Away from $\nu$=1, the ferromagnetic spin wave collapses and
a new low-energy spin wave emerges below the Zeeman gap. The emergent spin wave
shows soft behavior as its energy increases with temperature and reaches the
Zeeman energy for temperatures above 2 K. The observed softening indicates an
instability of the two dimensional electron gas towards a magnetic order that
breaks spin rotational symmetry. We discuss our findings in light of the
possible existence of a Skyrme crystal.",0709.0541v2
2009-03-24,Nematicity as a route to a magnetic field-induced spin density wave order; application to the high temperature cuprates,"The electronic nematic order characterized by broken rotational symmetry has
been suggested to play an important role in the phase diagram of the high
temperature cuprates. We study the interplay between the electronic nematic
order and a spin density wave order in the presence of a magnetic field. We
show that a cooperation of the nematicity and the magnetic field induces a
finite coupling between the spin density wave and spin-triplet staggered flux
orders. As a consequence of such a coupling, the magnon gap decreases as the
magnetic field increases, and it eventually condenses beyond a critical
magnetic field leading to a field-induced spin density wave order. Both
commensurate and incommensurate orders are studied, and the experimental
implications of our findings are discussed.",0903.3993v2
2009-10-03,Non-collinear spin-spiral phase for the uniform electron gas within Reduced-Density-Matrix-Functional Theory,"The non-collinear spin-spiral density wave of the uniform electron gas is
studied in the framework of Reduced-Density-Matrix-Functional Theory. For the
Hartree-Fock approximation, which can be obtained as a limiting case of
Reduced-Density-Matrix-Functional Theory, Overhauser showed a long time ago
that the paramagnetic state of the electron gas is unstable with respect to the
formation of charge or spin density waves. Here we not only present a detailed
numerical investigation of the spin-spiral density wave in the Hartree-Fock
approximation but also investigate the effects of correlations on the
spin-spiral density wave instability by means of a recently proposed
density-matrix functional.",0910.0534v1
2010-07-19,Spin waves in zigzag graphene nanoribbons and the stability of edge ferromagnetism,"We study the low energy spin excitations of zigzag graphene nanoribbons of
varying width. We find their energy dispersion at small wave vector to be
dominated by antiferromagnetic correlations between the ribbon's edges, in
accrodance with previous calculations. We point out that spin wave lifetimes
are very long due to the semi-conducting nature of the electrically neutral
nanoribbons. However, application of very modest gate voltages cause a
discontinuous transition to a regime of finite spin wave lifetime. By further
increasing doping the ferromagnetic alignments along the edge become unstable
against transverse spin fluctuations. This makes the experimental detection of
ferromagnetism is this class of systems very delicate, and poses a difficult
challenge to the possible uses of these nanoribbons as basis for spintronic
devices.",1007.3285v2
2011-02-17,A-phase origin in B20 helimagnets,"A-phase origin in cubic helimagnets ($M n S i,F e G e$ etc) is explained. It
is shown that its upper bound is a result of the spin-wave instability at
$H_\perp>\sqrt{8/3}\Delta=H_{A2}$ where $H_\perp$ are the magnetic field
perpendicular to the helix axis $\m k$ and $\Delta$ the spin-wave gap
respectively. The last appears due to the spin-wave interaction if one takes
into account that the Dzyaloshinskii-Moriya interaction acts between different
spins. The infra-red divergences (IRD) in the 1/S series for the magnetic
energy at $H_\perp\to H_{A2}$ are responsible for the lower A-phase boundary
$H_{A1}$. It is shown that the A-phase exists at all $T<T_C$ but if $T\ll T_C$
it is very narrow and can not be observed. However in the critical region just
below $T_C$ its width increasing strongly. Preliminary estimations demonstrate
semi-quantitative agreement with the existing experimental data.
  The existence of the spin-wave gap is a crucial point of our consideration.
In Appendix A we present its derivation in more transparent form than in
previous publication.",1102.3524v1
2011-03-09,Magnetization and magnon excitation energies of the magnetic semiconductors EuTe and EuO on the basis of the renormalized spin wave theory,"We present analytic expressions for the temperature dependent magnetization
and magnon dispersion relation of the antiferromagnetic (AFM) EuTe and the
ferromagnetic (FM) EuO. These bulk semiconductors represent concentrated spin
systems for which the interaction between magnons has to be taken into account.
We do this using the renormalized spin wave theory. A higher order Green's
function according to Tjablikov is used for their description. As a result, we
obtain a modified Bloch- T3/2 law, for low temperatures and high magnetic
fields. A full analytic expression is given for the sublattice magnetization of
the AFM EuTe (B0=0), with a N\'eel temperature of TN = 9.81 K. The
magnetization curves {\sigma}N(T) of EuO (for 0 \leq T \leq 0.68TC) and
{\sigma}R(T) (for 0.82TC < T < TC) agree well with experiment. The spin wave
excitation energy perfectly matches experimental data from inelastic neutron
scattering. In the case of EuTe the magnon excitation energies exhibit a
characteristic maximum. For q = 0, an energy gap Eg occurs in the spin wave
spectrum, a consequence of the AFM exchange interaction J2(T). Such energy gaps
exist in the spectrum of magnon excitation energies only in systems with AFM
interactions.",1103.1831v1
2011-05-31,Topological Entanglement Entropy of Z2 Spin liquids and Lattice Laughlin states,"We study entanglement properties of candidate wave-functions for SU(2)
symmetric gapped spin liquids and Laughlin states. These wave-functions are
obtained by the Gutzwiller projection technique. Using Topological Entanglement
Entropy \gamma\ as a tool, we establish topological order in chiral spin liquid
and Z2 spin liquid wave-functions, as well as a lattice version of the Laughlin
state. Our results agree very well with the field theoretic result \gamma =log
D where D is the total quantum dimension of the phase. All calculations are
done using a Monte Carlo technique on a 12 times 12 lattice enabling us to
extract \gamma\ with small finite size effects. For a chiral spin liquid
wave-function, the calculated value is within 4% of the ideal value. We also
find good agreement for a lattice version of the Laughlin \nu =1/3 phase with
the expected \gamma=log \sqrt{3}.",1106.0015v3
2011-07-11,Coherent manipulation of spin wave vector for polarization of photons in an atomic ensemble,"We experimentally demonstrate the manipulation of two-orthogonal components
of a spin wave in an atomic ensemble. Based on Raman two-photon transition and
Larmor spin precession induced by magnetic field pulses, the coherent rotations
between the two components of the spin wave is controllably achieved.
Successively, the two manipulated spin-wave components are mapped into two
orthogonal polarized optical emissions, respectively. By measuring Ramsey
fringes of the retrieved optical signals, the \pi/2-pulse fidelity of ~96% is
obtained. The presented manipulation scheme can be used to build an arbitrary
rotation for qubit operations in quantum information processing based on atomic
ensembles.",1107.1914v1
2013-04-22,Magnetic anisotropic energy gap and low energy spin wave excitation in antiferromagnetic block phase of K2Fe4Se5,"Neutron scattering experiments were performed to investigate magnetic order
and magnetic excitations in ternary iron chalcogenide K2Fe4Se5. The formation
of a superlattice structure below 580 K together with the decoupling between
the Fe-vacancy order-disorder transition and the antiferromagnetic order
transition appears to be a common feature in the A2Fe4Se5 family. The study of
spin dynamics of K2Fe4Se5 reveals two distinct energy gaps at the magnetic
Brillouin zone center, which indicates the presence of magnetic anisotropy and
the decrease of local symmetry due to electronic and orbital anisotropy. The
low-energy spin wave excitations of K2Fe4Se5 can be properly described by
linear spin wave theory within a Heisenberg model. Compared to iron pnictides,
K2Fe4Se5 exhibits a more two-dimensional magnetism as characterized by large
differences not only between out-of-plane and in-plane spin wave velocities,
but also between out-of-plane and in-plane exchange interactions.",1304.5950v1
2013-08-29,Control of Propagating Spin Waves via Spin Transfer Torque in a Metallic Bilayer Waveguide,"We investigate the effect of a direct current on propagating spin waves in a
CoFeB/Ta bilayer structure. Using the micro-Brillouin light scattering
technique, we observe that the spin wave amplitude may be attenuated or
amplified depending on the direction of the current and the applied magnetic
field. Our work suggests an effective approach for electrically controlling the
propagation of spin waves in a magnetic waveguide and may be useful in a number
of applications such as phase locked nano-oscillators and hybrid information
processing devices.",1308.6357v2
2013-11-21,Wave patterns generated by a flow of two-component Bose-Einstein condensate with spin-orbit interaction past a localized obstacle,"It is shown that spin-orbit interaction leads to drastic changes in wave
patterns generated by a flow of two-component Bose-Einstein condensate (BEC)
past an obstacle. The combined Rashba and Dresselhaus spin-orbit interaction
affects in different ways two types of excitations---density and polarization
waves---which can propagate in a two-component BEC. We show that the density
and polarization ""ship wave"" patterns rotate in opposite directions around the
axis located at the obstacle position and the angle of rotation depends on the
strength of spin-orbit interaction. This rotation is accompanied by narrowing
of the Mach cone. The influence of spin-orbit coupling on density solitons and
polarization breathers is studied numerically.",1311.5387v1
2013-12-19,Gravitational waves from spinning compact object binaries: New post-Newtonian results,"We report on recent results obtained in the post-Newtonian framework for the
modelling of the gravitational waves emitted by binary systems of spinning
compact objects (black holes and/or neutron stars). These new results are
obtained at the spin-orbit (linear-in-spin) level and solving Einstein's field
equations iteratively in harmonic coordinates as well as the multipolar
post-Newtonian formalism. The dynamics of the binary was tackled at the
next-to-next-to-leading order, corresponding to the 3.5 post-Newtonian (PN)
order for maximally spinning objects, and the result is found to be consistent
with a previously obtained reduced Hamiltonian in the ADM approach. The
corresponding contribution to the energy flux emitted by the binary was
obtained at the 3.5PN order, as well as the next-to-leading 4PN tail
contribution to this flux, an imprint of the non-linearity in the propagation
of the wave. These new terms can be used to build more accurate PN templates
for the next generation of gravitational wave detectors. We give an
illustrative estimate of the quantitative relevance of the new terms in the
orbital phasing of the binary.",1312.5375v1
2014-02-25,Linear spin wave theory for single-Q incommensurate magnetic structures,"Linear spin wave theory provides the leading term in the calculation of the
excitation spectra of long-range ordered magnetic systems as a function of
$1/\sqrt{S}$. This term is acquired using the Holstein-Primakoff approximation
of the spin operator and valid for small $\delta S$ fluctuations of the ordered
moment. We propose an algorithm that allows magnetic ground states with general
moment directions and single-Q incommensurate ordering wave vector using a
local coordinate transformation for every spin and a rotating coordinate
transformation for the incommensurability. Finally we show, how our model can
determine the spin wave spectrum of the magnetic C-site langasites with
incommensurate order.",1402.6069v4
2015-04-01,Direct observation and imaging of a spin-wave soliton with $p-$like symmetry,"The prediction and realization of magnetic excitations driven by electrical
currents via the spin transfer torque effect, enables novel magnetic
nano-devices where spin-waves can be used to process and store information. The
functional control of such devices relies on understanding the properties of
non-linear spin-wave excitations. It has been demonstrated that spin waves can
show both an itinerant character, but also appear as localized solitons. So
far, it was assumed that localized solitons have essentially cylindrical,
$s-$like symmetry. Using a newly developed high-sensitivity time-resolved
magnetic x-ray microscopy, we instead observe the emergence of a novel
localized soliton excitation with a nodal line, i.e. with $p-$like symmetry.
Micromagnetic simulations identify the physical mechanism that controls the
transition from $s-$ to $p-$like solitons. Our results suggest a potential new
pathway to design artificial atoms with tunable dynamical states using
nanoscale magnetic devices.",1504.00144v1
2015-05-07,Flat-band ferromagnetism in a topological Hubbard model,"We study the flat-band ferromagnetic phase of a topological Hubbard model
within a bosonization formalism and, in particular, determine the spin-wave
excitation spectrum. We consider a square lattice Hubbard model at 1/4-filling
whose free-electron term is the \pi-flux model with topologically nontrivial
and nearly flat energy bands. The electron spin is introduced such that the
model either explicitly breaks time-reversal symmetry (correlated flat-band
Chern insulator) or is invariant under time-reversal symmetry (correlated
flat-band $Z_2$ topological insulator). We generalize for flat-band Chern and
topological insulators the bosonization formalism [Phys. Rev. B 71, 045339
(2005)] previously developed for the two-dimensional electron gas in a uniform
and perpendicular magnetic field at filling factor \nu=1. We show that, within
the bosonization scheme, the topological Hubbard model is mapped into an
effective interacting boson model. We consider the boson model at the harmonic
approximation and show that, for the correlated Chern insulator, the spin-wave
excitation spectrum is gapless while, for the correlated topological insulator,
gapped. We briefly comment on the possible effects of the boson-boson
(spin-wave--spin-wave) coupling.",1505.01685v1
2015-08-09,Spin contamination and noncollinearity in general complex Hartree-Fock wave functions,"An expression for the square of the spin operator expectation value,
\textless{} S^2\textgreater{}, is obtained for a general complex Hartree-Fock
(GCHF) wave function and decomposed into four contributions: The main one whose
expression is formally identical to the restricted (open-shell) Hartree-Fock
expression. A spin contamination one formally analogous to that found for spin
unrestricted Hartree-Fock wave functions. A noncollinearity contribution
related to the fact that the wave function is not an eigenfunction of the
spin-S\_z operator. A perpendicularity contribution related to the fact that
the spin density is not constrained to be zero in the xy-plane. All these
contributions are evaluated and compared for the H\_2O^+ system. The
optimization of the collinearity axis is also considered.",1508.02058v2
2017-12-09,Magnonic waveguide based on exchange-spring magnetic structure,"We propose to use a soft/hard exchange-spring coupling bilayer magnetic
structure to introduce a narrow channel for spin-wave propagation. We show by
micromagnetic simulations that broad-band Damon-Eshbach geometry spin waves can
be strongly localized into the channel and propagate effectively with a proper
high group velocity. The beamwidth of the bound mode spin waves is almost
independent from the frequency and is smaller than 24nm. For a low-frequency
excitation, we further investigate the appearance of two other spin beams in
the lateral of the channel. In contrast to a domain wall, the channel formed by
exchange-spring coupling can be easier to realize in experimental scenarios and
holds stronger immunity to surroundings. This work is expected to open new
possibilities for energy-efficient spin-wave guiding as well as to help shape
the field of beam magnonics.",1712.03392v1
2018-07-30,Topological spin excitations in honeycomb ferromagnet CrI$_3$,"In two dimensional honeycomb ferromagnets, bosonic magnon quasiparticles
(spin waves) may either behave as massless Dirac fermions or form topologically
protected edge states. The key ingredient defining their nature is the
next-nearest neighbor Dzyaloshinskii-Moriya (DM) interaction that breaks the
inversion symmetry of the lattice and discriminates chirality of the associated
spin-wave excitations. Using inelastic neutron scattering, we find that spin
waves of the insulating honeycomb ferromagnet CrI$_3$ ($T_C=61$ K) have two
distinctive bands of ferromagnetic excitations separated by a $\sim$4 meV gap
at the Dirac points. These results can only be understood by considering a
Heisenberg Hamiltonian with DM interaction, thus providing experimental
evidence that spin waves in CrI$_3$ can have robust topological properties
useful for dissipationless spintronic applications.",1807.11452v3
2018-02-26,Unusual spin-wave dynamics in core-shell magnetic nanodisks,"We investigated the spin dynamics of a vortex state in a core-shell magnetic
nanodisk driven by an oscillating field applied perpendicular to the disk plane
by means of micromagnetic simulations. The nanodisk comprises a Py (Fe0.2Ni0.8)
core of 100 nm in radius, surrounded by a 50 nm thick Fe shell. Fourier
transform analyses show that the Py core and the Fe shell dominate spin-wave
oscillation at the fundamental and higher order radial modes, respectively. For
oscillating driving field tuned to the fundamental eigenfrequency, the Py/Fe
interface effectively confines spin-wave excitation in the Py core region. This
effect leads to significantly more rapid vortex core (VC) reversal in
comparison to homogeneous disks. Our work demonstrates that the higher order
modes can drive much faster VC reversal than the fundamental mode, in sharp
contrast to the results obtained in homogeneous disks. With excitation levels
up to 30 mT, we find strong nonlinear spin-wave dynamics in the system, which
results in mode frequency redshifting, therefore the observation of the most
rapid VC reversals below eigenfrequencies and VC switching in wide ranges of
frequencies.",1802.09181v1
2018-12-20,Tunable Angle Dependent Magnetization Dynamics in Ni80Fe20 Nano-cross Structures of Varying Size,"We demonstrate a large angular dependence of magnetization dynamics in
Ni80Fe20 nano-cross arrays of varying sizes. By subtle variation of the
azimuthal angle of an in-plane bias magnetic field, the spin configuration and
the ensuing spin-wave dynamics, including mode softening, mode splitting, mode
crossover and mode merging, can be drastically varied to the extent that a
frequency minimum corresponding to mode softening converts to a mode crossover,
various mode splitting and mode crossover disappear and additional mode
splitting appears. Numerically simulated spin-wave spectra and phase profiles
revealed the nature of various spin-wave modes and the origin of above
variation of the dynamics with bias-field angle. All of these above
observations are further modified with the variation of dimensions of the
nano-cross. The numerically calculated magnetostatic field distributions
further supports the variation of dynamics with bias-field angle. These results
open a new avenue for engineering the nano-cross based magnetic devices such as
magnetic storage, spin-wave logic and on-chip data communication devices.",1812.08393v1
2016-12-08,Damped spin-wave excitations in the itinerant antiferromagnet $γ$-Fe$_{0.7}$Mn$_{0.3}$,"The collective spin-wave excitations in the antiferromagnetic state of
$\gamma$-Fe$_{0.7}$Mn$_{0.3}$ were investigated using the inelastic neutron
scattering technique. The spin excitations remain isotropic up to the high
excitation energy, ${\hbar\omega}= 78$ meV. The excitations gradually become
broad and damped above 40 meV. The damping parameter ${\gamma}$ reaches 110(16)
meV at ${\hbar\omega} = 78$ meV, which is much larger than that for other
metallic compounds, e.g., CaFe$_2$As$_2$ (24 meV),
La$_{2-2x}$Sr$_{1+2x}$Mn$_2$O$_7$ ($52-72$ meV), and Mn$_{90}$Cu$_{10}$ (88
meV). In addition, the spin-wave dispersion shows a deviation from the relation
$({\hbar\omega})^2 = c^2q^2 + {\Delta}^2$ above 40 meV. The group velocity
above this energy increases to 470(40) meV{\AA}, which is higher than that at
the low energies, $c = 226(5)$ meV{\AA}. These results could suggest that the
spin-wave excitations merge with the continuum of the individual particle-hole
excitations at 40 meV.",1612.02515v2
2017-02-26,Magnon-photon coupling in antiferromagnets,"Magnon-photon coupling in antiferromagnets has many attractive features that
do not exist in ferro- or ferrimagnets. We show quantum-mechanically that, in
the absence of an external field, one of the two degenerated spin wave bands
couples with photons while the other does not. The photon mode anticrosses with
the coupled spin waves when their frequencies are close to each other. Similar
to its ferromagnetic counterpart, the magnon-photon coupling strength is
proportional to the square root of number of spins $\sqrt{N}$ in
antiferromagnets. An external field removes the spin wave degeneracy and both
spin wave bands couple to the photons, resulting in two anticrossings between
the magnons and photons. Two transmission peaks were observed near the
anticrossing frequency. The maximum damping that allows clear discrimination of
the two transmission peaks is proportional to $\sqrt{N}$ and it's well below
the damping of antiferromagnetic insulators. Therefore the strong magnon-photon
coupling can be realized in antiferromagnets and the coherent information
transfer between the photons and magnons is possible.",1702.07977v1
2017-06-02,Coherent Terahertz Spin-Wave Emission Associated with Ferrimagnetic Domain Wall Dynamics,"We theoretically study the dynamics of ferrimagnetic domain walls in the
presence of Dzyaloshinskii-Moriya interaction. We find that an application of a
DC magnetic field can induce terahertz spin-wave emission by driving
ferrimagnetic domain walls, which is not possible for ferromagnetic or
antiferromagnetic domain walls. Dzyaloshinskii-Moriya interaction is shown to
facilitate the teraherz spin-wave emission in wide ranges of net angular
momentum by increasing the Walkerbreakdown field. Moreover, we show that
spin-orbit torque combined with Dzyaloshinskii-Moriya interaction also drives a
fast ferrimagnetic domain wall motion with emitting terahertz spin-waves in
wide ranges of net angular momentum.",1706.00549v1
2021-08-08,Shock-wave-like emission of spin waves induced by interfacial Dzyaloshinskii-Moriya interaction,"We investigated spin wave (SW) propagation and emission in thin film systems
with strong interfacial Dzyaloshinskii-Moriya interaction (DMI) utilizing
micromagnetic simulation. The effect of DMI on SW propagation is analogous to
the flow of magnetic medium leading to the spin Doppler effect, and a
spin-polarized current can enhance or suppress it. It is demonstrated that, for
a Doppler velocity exceeding a critical value, a shock-wave-like emission of
SWs with a cone-shape emerges from a magnetically irregular point as the cone
apex. The cone angle is quantitatively determined by the DMI-induced Doppler
velocity. Combining the interfacial DMI and the spin-polarized current, a
constant SW emission by a static source is demonstrated, which provides a
promising route to efficiently generate SWs with tunable frequency.",2108.03686v1
2019-10-25,Nutation Wave as a Platform for Ultrafast Spin Dynamics in Ferromagnets,"At short time scales the inertia term becomes relevant for the magnetization
dynamics of ferromagnets and leads to nutation for the magnetization vector.
For the case of spatially extended magnetic systems, for instance Heisenberg
spin chains with isotropic spin-exchange interaction, this leads to the
appearance of a novel collective excitation, the ""nutation wave"", whose
properties are elucidated by analytic arguments and numerical studies. The
one--particle excitations can be identified as relativistic massive particles.
These particles, the ""nutatons"", acquire their mass via the Brout-Englert-Higgs
mechanism, through the interaction of the wave with an emergent topological
gauge field. This spin excitation would appear as a peak in the spectrum of the
scattering structure factor in inelastic neutron scattering experiments. The
high frequency and speed of the nutation wave can open new paths for realizing
ultrafast spin dynamics.",1910.11897v3
2020-05-21,Non-Hermitian coherent coupling of nanomagnets by exchange spin waves,"Non-Hermitian physics has recently attracted much attention in optics and
photonics. Less explored is non-Hermitian magnonics that provides opportunities
to take advantage of the inevitable dissipation of magnons or spin waves in
magnetic systems. Here we demonstrate non-Hermitian coherent coupling of two
distant nanomagnets by fast spin waves with sub-50 nm wavelengths. Magnons in
two nanomagnets are unidirectionally phase-locked with phase shifts controlled
by magnon spin torque and spin-wave propagation. Our results are attractive for
analog neuromorphic computing that requires unidirectional information
transmission.",2005.10452v1
2020-05-22,Dipolar spin waves in uniaxial easy-axis antiferromagnets: A natural topological nodal-line semimetal,"The existence of the magnetostatic surface spin waves in ferromagnets, known
as Damon-Eshbach mode, was recently demonstrated to originate from the topology
of the dipole-dipole interaction. In this work, we study the topological
characteristics of magnons in easy-axis antiferromagnets with uniaxial
anisotropy. The dipolar spin waves are found to be, driven by the dipole-dipole
interaction, in a topological nodal-line semimetal phase, which hosts
Damon-Eshbach-type surface modes due to the bulk-edge correspondence. The long
wavelength character of dipolar spin waves makes our proposal valid for any
natural uniaxial easy-axis antiferromagnet, and thus enriches the candidates of
topological magnonic materials. In contrast to the nonreciprocal property in
ferromagnetic case, the surface modes with opposite momentum coexist at each
surface, but with different chiralities. Such a chirality-momentum or
spin-momentum locking, similar to that of electronic surface states in
topological insulators, offers the opportunity to design novel chirality-based
magnonic devices in antiferromagnets.",2005.10971v1
2023-04-21,Magnetic Structures and Spin-wave Excitations in Rare-Earth Iron Garnets near the Compensation Temperature,"We introduce a simple model for the ferrimagnetic non-collinear ``magnetic
umbrella"" states of rare-earth iron garnets (REIG), common when the rare-earth
moments have non-zero orbital angular momentum. The spin-wave excitations are
calculated within linear spin wave theory and temperature effects via
mean-field theory. This could be used to determine the magnetic polarization of
each mode and thereby the spin currents generated by thermal excitations
including the effects of mixed chirality. The spectra reproduce essential
features seen in more complete models, with hybridization between the rare
earth crystal field excitations and the propagating mode on the iron moments.
By the symmetry of the model, only one rare earth mode hybridizes, inducing a
gap at zero wave number and level repulsion at finite frequency. At the
compensation point, the hybridization gap closes and finally, as we approach
the N\'eel temperature, the hybridization gap appears to reopen. The chirality
of the lowest mode changes its sign around the frequency at which the level
repulsion occurs. This is important to estimate the spin current generation in
REIGs.",2304.10695v1
2023-10-01,Spin and orbital angular momenta of electromagnetic waves in classical and quantum electrodynamics,"A plane, monochromatic electromagnetic wave propagating in free space can
have a certain amount of spin angular momentum but cannot possess any orbital
angular momentum. Even the spin angular momentum of the plane-wave is difficult
to evaluate without resort to certain mathematical limit arguments. Both spin
and orbital angular momenta can be computed for a wavepacket of finite duration
and finite cross-sectional area using standard methods of classical
electrodynamics. Extending these results to finite wavepackets in quantum
electrodynamics requires subtle arguments in conjunction with the multimodal
structure of the wavepacket. This paper presents some of the nuances of
classical as well as quantum-optical methods for analyzing the spin and orbital
angular momenta of electromagnetic waves.",2310.00575v1
2024-01-16,Spin Waves in Ferrimagnets near the Angular Magnetization Compensation Temperature: A Micromagnetic Study,"Spin wave propagation along a ferrimagnetic strip with out-of-plane
magnetization is studied by means of micromagnetic simulations. The
ferrimagnetic material is considered as formed by two antiferromagnetically
coupled sublattices. Two critical temperatures can be defined for such systems:
that of magnetization compensation and that of angular momentum compensation,
both different due to distinct Land\'e factors for each sub-lattice. Spin waves
in the strip are excited by a spin current injected at one of its edges. The
obtained dispersion diagrams show exchange-dominated forward volume spin waves.
For a given excitation frequency, N\'eel vector describes highly eccentric
orbits, the eccentricity depending on temperature, whose semi-major axis are
oriented differently at distinct locations on the FiM strip.",2401.08235v1
2011-05-25,Gravito-electromagnetic resonances,"The interaction between gravitational and electromagnetic radiation has a
rather long research history. It is well known, in particular, that
gravity-wave distortions can drive propagating electromagnetic signals. Since
forced oscillations provide the natural stage for resonances to occur,
gravito-electromagnetic resonances have been investigated as a means of more
efficient gravity-wave detection methods. In this report, we consider the
coupling between the Weyl and the Maxwell fields on a Minkowski background,
which also applies to astrophysical environments where gravity is weak, at the
second perturbative level. We use covariant methods that describe gravitational
waves via the transverse component of the shear, instead of pure-tensor metric
perturbations. The aim is to calculate the properties of the electromagnetic
signal, which emerges from the interaction of its linear counterpart with an
incoming gravitational wave. Our analysis shows how the wavelength and the
amplitude of the gravitationally driven electromagnetic wave vary with the
initial conditions. More specifically, for certain initial data, the amplitude
of the induced electromagnetic signal is found to diverge. Analogous,
diverging, gravito-electromagnetic resonances were also reported in cosmology.
Given that, we extend our Minkowski-space study to cosmology and discuss
analogies and differences in the physics and in the phenomenology of the
Weyl-Maxwell coupling between the aforementioned two physical environments.",1105.5103v2
2018-03-30,Ioffe-Regel criterion of Anderson localization in the model of resonant point scatterers,"We establish a phase diagram of a model in which scalar waves are scattered
by resonant point scatterers pinned at random positions in the free
three-dimensional (3D) space. A transition to Anderson localization takes place
in a narrow frequency band near the resonance frequency provided that the
number density of scatterers $\rho$ exceeds a critical value $\rho_c \simeq
0.08 k_0^{3}$, where $k_0$ is the wave number in the free space. The
localization condition $\rho > \rho_c$ can be rewritten as $k_0 \ell_0 < 1$,
where $\ell_0$ is the on-resonance mean free path in the independent-scattering
approximation. At mobility edges, the decay of the average amplitude of a
monochromatic plane wave is not purely exponential and the growth of its phase
is nonlinear with the propagation distance. This makes it impossible to define
the mean free path $\ell$ and the effective wave number $k$ in a usual way. If
the latter are defined as an effective decay length of the intensity and an
effective growth rate of the phase of the average wave field, the Ioffe-Regel
parameter $(k\ell)_c$ at the mobility edges can be calculated and takes values
from 0.3 to 1.2 depending on $\rho$. Thus, the Ioffe-Regel criterion of
localization $k\ell < (k\ell)_c = \mathrm{const} \sim 1$ is valid only
qualitatively and cannot be used as a quantitative condition of Anderson
localization in 3D.",1803.11479v2
2016-12-28,Temporal Solitons in Microresonators driven by Optical Pulses,"Continuous-wave laser driven Kerr-nonlinear, optical microresonators have
enabled a variety of novel applications and phenomena including the generation
of optical frequency combs, ultra-low noise microwaves, as well as, ultra-short
optical pulses. In this work we break with the paradigm of the continuous-wave
optical drive and use instead periodic, pico-second optical pulses. We observe
the deterministic generation of stable femtosecond dissipative cavity solitons
on-top of the resonantly enhanced driving pulse. Surprisingly, the soliton
pulse locks to the driving pulse enabling direct all-optical control of both
the soliton's repetition rate and carrier-envelope offset frequency without the
need for any actuation on the microresonator. When compared to both
continuous-wave driven microresonators and non-resonant pulsed supercontinuum
generation, this new approach is substantially more efficient and can yield
broadband frequency combs at femto-Joule driving pulse energies and average
laser powers significantly below the parametric threshold power of
continuous-wave driven microresonators. The presented results bridge the fields
of continuous-wave driven resonant and pulse-driven non-resonant nonlinear
optics. They enables micro-photonic pulse compression, ultra-efficient low
noise frequency comb and resonant supercontinuum generation for applications
including optical data transfer and optical spectroscopy. From a scientific
perspective the results open a new horizon for nonlinear photonics driven by
temporally and spectrally structured light.",1612.08993v1
2019-08-06,Mitigation of seismic waves: metabarriers and metafoundations bench tested,"The article analyses two potential metamaterial designs, the metafoundation
and the metabarrier, capable to attenuate seismic waves on buildings or
structural components in a frequency band between 3.5 to 8 Hz. The
metafoundation serves the dual purpose of reducing the seismic response and
supporting the superstructure. Conversely the metabarrier surrounds and shields
the structure from incoming waves. The two solutions are based on a cell layout
of local resonators whose dynamic properties are tuned using finite element
simulations combined with Bloch-Floquet boundary conditions. To enlarge the
attenuation band, a graded design where the resonant frequency of each cell
varies spatially is employed. If appropriately enlarged or reduced, the
metamaterial designs could be used to attenuate lower frequency seismic waves
or groundborne vibrations respectively. A sensitivity analysis over various
design parameters including size, number of resonators, soil type and source
directivity, carried out by computing full 3D numerical simulations in time
domain for horizontal shear waves is proposed. Overall, the metamaterial
solutions discussed here can reduce the spectral amplification of the
superstructure between approx. 15 to 70% depending on several parameters
including the metastructure size and the properties of the soil. Pitfalls and
advantages of each configuration are discussed in detail. The role of damping,
crucial to avoid multiple resonant coupling, and the analogies between graded
metamaterials and tuned mass dampers is also investigated.",1908.02056v2
2020-01-28,A Self-Matched Leaky-Wave Antenna for Ultrahigh-Field MRI with Low SAR,"The technology of magnetic resonance imaging is developing towards higher
magnetic fields to improve resolution and contrast. However, whole-body imaging
at 7 T or even higher fields remains challenging due to wave interference,
tissue inhomogneities and high RF power deposition. Nowadays, proper RF
excitation of a human body in prostate and cardiac MRI is only possible to
achieve by using phased arrays of antennas attached to the body (so-called
surface coils). Due to safety concerns, the design of such coils aims to
minimize the local specific absorption rate (SAR) keeping the highest possible
RF signal in the region of interest. All previously demonstrated approaches
were based on resonant structures such as e. g.dipoles, capacitively-loaded
loops, TEM-line sections. In this study, we show that there is a better
compromise between the transmit signal and the local SAR using non-resonant
surface coils due to weaker RF near fields in the close proximity of their
conductors. With this aim, we propose and experimentally demonstrate a first
leaky-wave surface coil implemented as a periodically-slotted microstrip
transmission line. Due to its non-resonant radiation, the proposed coil induces
only slightly over half the peak local SAR compared to a state-of-the-art
dipole coil, but has the same transmit efficiency in prostate imaging at 7 T.
Unlike other coils, the leaky-wave coil intrinsically matches its input
impedance to the averaged wave impedance of body tissues in a broad frequency
range, which makes it very attractive for future clinical applications of 7 T
MRI.",2001.10410v1
2021-03-06,The Solution of the Long-Wave Equation for Various Nonlinear Depth and Breadth Profiles in the Power-Law Form,"Long waves bring many important challenges in the ocean and coastal
engineering, including but are not limited to harbor resonance and run-up.
Therefore, understanding and modeling their dynamics is crucially important.
Although their dynamics over various types of geometries are well-studied in
the literature, the study of the geometries with power-law variations remains
an open problem in this setting. With this motivation, in this paper, we derive
the exact analytical solutions of the long-wave equation over nonlinear depth
and breadth profiles having power-law forms given by $h(x)=c_1 x^a$ and
$b(x)=c_2 x^c$, where the parameters $c_1, c_2, a, c$ are some constants. We
show that for these types of power-law forms of depth and breadth profiles, the
long-wave equation admits solutions in terms of Bessel functions and
Cauchy-Euler series. We also derive the seiching periods and resonance
conditions for these forms of depth and breadth variations. Our results can be
used to investigate the long-wave dynamics and their envelope characteristics
over equilibrium beach profiles, the effects of nonlinear harbor entrances and
angled nonlinear seawall breadth variations in the power-law forms on these
dynamics, and the effects of reconstruction, geomorphological changes,
sedimentation, and dredging to harbor resonance, to the shift in resonance
periods and to the seiching characteristics in lakes and barrages.",2103.04153v2
2023-09-12,Non-reciprocal absorption and zero reflection in physically separated dual photonic resonators by traveling-wave-induced indirect coupling,"We experimentally explored novel behaviors of non-reciprocal absorption and
almost zero reflection in a dual photon resonator system, which is physically
separated and composed of two inverted split ring resonators (ISRRs) with
varying inter-distances. We also found that an
electromagnetically-induced-transparency (EIT)-like peak at a specific
inter-distance of d = 18 mm through traveling waves flowing along a shared
microstrip line to which the dual ISRRs are dissipatively coupled. With the aid
of CST-simulations and analytical modeling, we found that destructive and/or
constructive interferences in traveling waves, indirectly coupled to each ISRR,
result in a traveling-wave-induced transparency peak within a narrow window.
Furthermore, we observed not only strong non-reciprocal responses of
reflectivity and absorptivity at individual inter-distances exactly at the
corresponding EIT-like peak positions, but also nearly zero reflection and
almost perfect absorption for a specific case of d = 20 mm. Finally, the
unidirectional absorptions with zero reflection at d = 20 mm are found to be
ascribed to a non-Hermitian origin. This work not only provides a better
understanding of traveling-wave-induced indirect coupling between two photonic
resonators without magnetic coupling, but also suggests potential implications
for the resulting non-reciprocal behaviors of absorption and reflection in
microwave circuits and quantum information devices.",2309.06035v1
2001-04-25,"Electron Spin Resonance of Ni-doped CuGeO$_3$ in the paramagnetic, spin-Peierls and antiferromagnetic states: Comparison with non-magnetic impurities","We have performed Electron Spin Resonance measurements on single crystals of
the doped spin-Peierls compounds CuGe$_{1-y}$Si$_y$O$_3$ and
Cu$_{1-x}$M$_x$GeO$_3$ with M = Zn, Mg, Ni ($x, y\leq 0.1$). The first part of
our experiments was performed in the paramagnetic and spin-Peierls phases at
9.5, 95 and 190 GHz. All non-magnetic impurities (Si, Zn and Mg) were found to
hardly affect the position and linewidth of the single line resonance, in spite
of the moment formation due to the broken chains. In contrast to Si, Zn and
Mg-doping, the presence of Ni (S = 1) at low concentration induces a
spectacular shift towards high fields of the ESR line (up to 40% for x=0.002),
together with a large broadening. This shift is strictly proportional to the
ratio of Ni to Cu susceptibilities: Hence it is strongly enhanced below the
spin-Peierls transition. We interpret this shift and the broadening as due to
the exchange field induced by the Ni ions onto the strongly exchange coupled Cu
spins. Second, the antiferromagnetic resonance was investigated in Ni-doped
samples. The frequency vs magnetic field relation of the resonance is well
explained by the classical theory with orthorhombic anisotropy, with $g$ values
remarkably reduced, in accordance with the study of the spin-Peierls and
paramagnetic phases. The easy, second-easy, and hard axes are found to be $a$,
$c$, and $b$ axes, respectively. These results, which are dominated by the
single ion anisotropy of Ni$^{2+}$, are discussed in comparison with those in
the Zn- and Si-doped CuGeO$_3$.",0104498v2
2012-10-10,Bodily tides near the 1:1 spin-orbit resonance. Correction to Goldreich's dynamical model,"Spin-orbit coupling is often described in the ""MacDonald torque"" approach
which has become the textbook standard. Within this method, a concise
expression for the additional tidal potential, derived by MacDonald (1964; Rev.
Geophys. 2, 467), is combined with an assumption that the Q factor is
frequency-independent (i.e., that the geometric lag angle is constant in time).
This makes the approach unphysical because MacDonald's derivation of the said
formula was implicitly based on keeping the time lag frequency-independent,
which is equivalent to setting Q to scale as the inverse tidal frequency. The
contradiction requires the MacDonald treatment of both non-resonant and
resonant rotation to be rewritten.
  The non-resonant case was reconsidered by Efroimsky & Williams (2009; CMDA
104, 257), in application to spin modes distant from the major
commensurabilities. We continue this work by introducing the necessary
alterations into the MacDonald-torque-based model of falling into a 1:1
resonance. (For the original version of the model, see Goldreich 1966; AJ 71,
1.)
  We also study the effect of the triaxiality on both circulating and librating
rotation near the synchronous state. Circulating rotation may evolve toward the
libration region or toward a spin rate larger than synchronous
(pseudosynchronous spin). Which behaviour depends on the eccentricity, the
triaxiality of the primary, and the mass ratio of the secondary and primary
bodies. The spin evolution will always stall for the oblate case. For
small-amplitude librations, expressions are derived for the libration
frequency, damping rate, and average orientation.
  However, the stability of pseudosynchronous spin hinges upon the dissipation
model. Makarov and Efroimsky (2012; arXiv:1209.1616) have found that a more
realistic dissipation model than the corrected MacDonald torque makes
pseudosynchronous spin unstable.",1210.2923v3
2021-08-02,"Dynamics of Colombo's Top: Tidal Dissipation and Resonance Capture, With Applications to Oblique Super-Earths, Ultra-Short-Period Planets and Inspiraling Hot Jupiters","We present a comprehensive theoretical study on the spin evolution of a
planet under the combined effects of tidal dissipation and gravitational
perturbation from an external companion. Such a ""spin + companion"" system
(called Colombo's top) appears in many [exo]planetary contexts. The competition
between the tidal torque (which drives spin-orbit alignment and
synchronization) and the gravitational torque from the companion (which drives
orbital precession of the planet) gives rise to two possible spin equilibria
(""Tidal Cassini Equilibria"", tCE) that are stable and attracting: the ""simple""
tCE1, which typically has a low spin obliquity, and the ""resonant"" tCE2, which
can have a significant obliquity. The latter arises from a spin-orbit resonance
and can be broken when the tidal alignment torque is stronger than the
precessional torque from the companion. We characterize the long-term evolution
of the planetary spin (both magnitude and obliquity) for an arbitrary initial
spin orientation, and develop a new theoretical method to analytically obtain
the probability of resonance capture driven by tidal dissipation. Applying our
general theoretical results to exoplanetary systems, we find that a super-Earth
(SE) with an exterior companion can have a substantial probability of being
trapped in the high-obliquity tCE2, assuming that SEs have a wide range of
primordial obliquities. We also evaluate the recently proposed ""obliquity tide""
scenarios for the formation of ultra-short-period Earth-mass planets and for
the orbital decay of hot Jupiter WASP-12b. We find in both cases that the
probability of resonant capture into tCE2 is generally low and that such a
high-obliquity state can be easily broken by the required orbital decay.",2108.01082v2
1998-02-13,The Matrix Product Approach to Quantum Spin Ladders,"We present a manifestly rotational invariant formulation of the matrix
product method valid for spin chains and ladders. We apply it to 2 legged spin
ladders with spins 1/2, 1 and 3/2 and different magnetic structures labelled by
the exchange coupling constants, which can be ferromagnetic or
antiferromagnetic along the legs and the rungs of the ladder We compute ground
state energy densities, correlation lengths and string order parameters. We
present numerical evidence of the duality properties of the 3 different non
ferromagnetic spin 1/2 ladders. We show that the long range topological order
characteristic of isolated spin 1 chains is broken by the interchain coupling.
The string order correlation function decays exponentially with a finite
correlation length that we compute. A physical picture of the spin 1 ladder is
given in terms of a collection of resonating spin 1 chains. Finally for ladders
with spin equal or greater than 3/2 we define a class of AKLT states whose
matrix product coefficients are given by 9-j symbols.",9802150v1
2001-07-02,Thermodynamics and Spin Tunneling Dynamics in Ferric Wheels with Excess Spin,"We study theoretically the thermodynamic properties and spin dynamics of a
class of magnetic rings closely related to ferric wheels, antiferromagnetic
ring systems, in which one of the Fe (III) ions has been replaced by a dopant
ion to create an excess spin. Using a coherent-state spin path integral
formalism, we derive an effective action for the system in the presence of a
magnetic field. We calculate the functional dependence of the magnetization and
tunnel splitting on the magnetic field and show that the parameters of the spin
Hamiltonian can be inferred from the magnetization curve. We study the spin
dynamics in these systems and show that quantum tunneling of the Neel vector
also results in tunneling of the total magnetization. Hence, the spin
correlation function shows a signature of Neel vector tunneling, and electron
spin resonance (ESR) techniques or AC susceptibility measurements can be used
to measure both the tunneling and the decoherence rate. We compare our results
with exact diagonalization studies on small ring systems. Our results can be
easily generalized to a wide class of nanomagnets, such as ferritin.",0107025v1
2003-03-10,Rashba-effect-induced spin dephasing in n-typed InAs quantum wells,"We perform a many-body investigation of the spin dephasing in $n$-typed InAs
quantum wells under moderate magnetic fields in the Voigt configuration by
constructing and numerically solving the kinetic Bloch equations. We obtain the
spin dephasing time due to the Rashba effect together with the spin conserving
scattering such as the electron-phonon, the electron-nonmagnetic impurity as
well as the electron-electron Coulomb scattering. By varying the initial spin
polarization, temperature, impurity density, applied magnetic field and the
interface electric field, we are able to study the spin dephasing time under
various conditions. For the electron density and quantum well width we study,
the many-body effect dominates the spin dephasing. Moreover, we find an
anomalous resonance peak in the spin dephasing time for high initial spin
polarization under moderate magnetic fields.",0303169v1
2005-09-05,Spin dynamics in HTSC cuprates: The singlet--correlated band (or t-J-V) model and its applications,"So far calculations of the spin susceptibility in the superconducting state
of cuprates have been performed in the framework of weak-coupling
approximations. However, it is known that cuprates belong to Mott-Hubbard doped
materials where electron correlations are important. In this paper an
analytical expression for the spin susceptibility in the superconducting state
of cuprates is derived within the singlet-correlated band model, which takes
into account strong correlations. The expression of the spin susceptibility is
evaluated using values for the hopping parameters adapted to measurements of
the Fermi surface of the materials YBa2Cu3O7 and Bi2Sr2CaCu2O8. We show that
the available experimental data which are directly related to the spin
susceptibility can be explained consistently within one set of model parameters
for each material. These experiments include the magnetic resonance peak
observed by inelastic neutron scattering and the temperature dependence of the
NMR spin shift, spin-spin and spin-lattice relaxation rates in the
superconducting state.",0509110v1
2005-11-16,Magnetization and spin-spin energy diffusion in the XY model: a diagrammatic approach,"It is shown that the diagrammatic cluster expansion technique for equilibrium
averages of spin operators may be straightforwardly extended to the calculation
of time-dependent correlation functions of spin operators. We use this
technique to calculate exactly the first two non-vanishing moments of the
spin-spin and energy-energy correlation functions of the XY model with
arbitrary couplings, in the long-wavelength, infinite temperature limit
appropriate for spin diffusion. These moments are then used to estimate the
magnetization and spin-spin energy diffusion coefficients of the model using a
phenomenological theory of Redfield. Qualitative agreement is obtained with
recent experiments measuring diffusion of dipolar energy in calcium fluoride.",0511399v1
2007-01-25,Polynomially scaling spin dynamics simulation algorithm based on adaptive state space restriction,"The conventional spin dynamics simulations are performed in direct products
of state spaces of individual spins. In a general system of n spins, the total
number of elements in the state basis is >4^n. A system propagation step
requires an action by an operator on the state vector and thus requires >4^2n
multiplications. It is obvious that with current computers there is no way
beyond about ten spins, and the calculation complexity scales exponentially
with the spin system size.
  We demonstrate that a polynomially scaling algorithm can be obtained if the
state space is reduced by neglecting unimportant or unpopulated spin states.
The class of such states is surprisingly wide. In particular, there are
indications that very high multi-spin orders can be dropped completely, as can
all the orders linking the spins that are remote on the interaction graph.
  The computational cost of the propagation step for a ktuples-restricted
densely connected n-spin system with k<<n is O(n^2k). In cases of favourable
interaction topologies (narrow graphs, e.g. in protein NMR) the asymptotic
scaling is linear.",0701294v1
2008-01-07,Magnetization reversal driven by spin-injection : a mesoscopic spin-transfer effect,"A mesoscopic description of spin-transfer effect is proposed, based on the
spin-injection mechanism occurring at the junction with a ferromagnet. The
effect of spin-injection is to modify locally, in the ferromagnetic
configuration space, the density of magnetic moments. The corresponding
gradient leads to a current-dependent diffusion process of the magnetization.
In order to describe this effect, the dynamics of the magnetization of a
ferromagnetic single domain is reconsidered in the framework of the
thermokinetic theory of mesoscopic systems. Assuming an Onsager
cross-coefficient that couples the currents, it is shown that spin-dependent
electric transport leads to a correction of the Landau-Lifshitz-Gilbert
equation of the ferromagnetic order parameter with supplementary diffusion
terms. The consequence of spin-injection in terms of activation process of the
ferromagnet is deduced, and the expressions of the effective energy barrier and
of the critical current are derived. Magnetic fluctuations are calculated: the
correction to the fluctuations is similar to that predicted for the activation.
These predictions are consistent with the measurements of spin-transfer
obtained in the activation regime and for ferromagnetic resonance under
spin-injection.",0801.1019v1
2008-04-09,Quenching Spin Decoherence in Diamond through Spin Bath Polarization,"We experimentally demonstrate that the decoherence of a spin by a spin bath
can be completely eliminated by fully polarizing the spin bath. We use electron
paramagnetic resonance at 240 gigahertz and 8 Tesla to study the spin coherence
time $T_2$ of nitrogen-vacancy centers and nitrogen impurities in diamond from
room temperature down to 1.3 K. A sharp increase of $T_2$ is observed below the
Zeeman energy (11.5 K). The data are well described by a suppression of the
flip-flop induced spin bath fluctuations due to thermal spin polarization.
$T_2$ saturates at $\sim 250 \mu s$ below 2 K, where the spin bath polarization
is 99.4 %.",0804.1537v1
2008-07-04,Quantum interference and spin polarization on Rashba double quantum dots,"We report on the quantum interference and spin accumulation on double quantum
dots with Rashba spin-orbit coupling and electron-electron interaction, based
on the Keldysh nonequilibrium Green function formalism. It is shown that Rashba
spin-orbit interaction can strongly affect the conductance spectrum. By
gradually increasing the Rashba parameter from zero, Fano resonances in strong
overlap regime continuously evolve to resolve antiresonances. This transition
is ascribed to the phase shift of couplings between molecular states and the
lead due to spin precession. We also show that both bias and Rashba effect
strengthen the induced spin polarization in this device. For particular energy
position, up- and down-spin electron occupation can intersect to form a
crossing point. Spin polarization on different side of this point has opposite
sign in consequence. The magnitude and direction of spin polarization are
therefore controllable by tuning the dot levels and the Rashba parameter
through gates.",0807.0670v1
2008-09-23,Electrical detection of spin pumping: dc voltage generated by ferromagnetic resonance at ferromagnet/nonmagnet contact,"We describe electrical detection of spin pumping in metallic nanostructures.
In the spin pumping effect, a precessing ferromagnet attached to a normal-metal
acts as a pump of spin-polarized current, giving rise to a spin accumulation.
The resulting spin accumulation induces a backflow of spin current into the
ferromagnet and generates a dc voltage due to the spin dependent conductivities
of the ferromagnet. The magnitude of such voltage is proportional to the
spin-relaxation properties of the normal-metal. By using platinum as a contact
material we observe, in agreement with theory, that the voltage is
significantly reduced as compared to the case when aluminum was used.
Furtheremore, the effects of rectification between the circulating rf currents
and the magnetization precession of the ferromagnet are examined. Most
significantly, we show that using an improved layout device geometry these
effects can be minimized.",0809.3859v1
2009-04-03,Ultrafast optical spin echo for electron spins in semiconductors,"Spin-based quantum computing and magnetic resonance techniques rely on the
ability to measure the coherence time, T2, of a spin system. We report on the
experimental implementation of all-optical spin echo to determine the T2 time
of a semiconductor electron-spin system. We use three ultrafast optical pulses
to rotate spins an arbitrary angle and measure an echo signal as the time
between pulses is lengthened. Unlike previous spin-echo techniques using
microwaves, ultrafast optical pulses allow clean T2 measurements of systems
with dephasing times T2* fast in comparison to the timescale for microwave
control. This demonstration provides a step toward ultrafast optical dynamic
decoupling of spin-based qubits.",0904.0632v1
2009-06-19,Spin Filtering in a Nonuniform Quantum Wire with Rashba Spin-Orbit Interaction,"We investigate theoretically the spin-polarized electron transport for a
wide-narrow-wide (WNW) quantum wire under the modulation of Rashba spin-orbit
interaction (SOI). The influence of both the structure of the quantum wire and
the interference between different pairs of subbands on the spin-polarized
electron transport is taken into account simultaneously via the spin-resolved
lattice Green function method. It is found that a very large vertical
spin-polarized current can be generated by the SOI-induced effective magnetic
field at the structure-induced Fano resonance even in the presence of strong
disorder. Furthermore, the magnitude of the spin polarization can be tuned by
both the Rashba SOI strength and structural parameters. Our results may provide
an effective way to design a spin filter device without containing any magnetic
materials or applying a magnetic field.",0906.3561v1
2009-09-14,"""Listening"" to the spin noise of conduction electrons in bulk n:GaAs","We report a comprehensive study of stochastic electron spin fluctuations --
spin noise -- in lightly doped ($n$-type) bulk GaAs, which are measured using
sensitive optical magnetometry based on off-resonant Faraday rotation.
Frequency spectra of electron spin noise are studied as a function of electron
density, magnetic field, temperature, probe laser wavelength and intensity, and
interaction volume. Electron spin lifetimes $\tau_s$ are inferred from the
width of the spin noise spectra, and are compared with direct measurements of
$\tau_s$ using conventional Hanle effect methods. Both methods reveal a strong
and similar dependence of $\tau_s$ on the wavelength and intensity of the probe
laser, highlighting the undesired influence of sub-bandgap absorption effects
on the nominally `non-perturbative' spin noise measurements. As a function of
temperature, the spin noise power increases approximately linearly from 1.5 K
to 30 K, as expected for degenerate electrons obeying Fermi-Dirac statistics,
but with an additional zero-temperature offset. Finally, as the cross-sectional
area of the probe laser shrinks and fewer electrons are probed, the measured
Faraday rotation fluctuations due to electron spin noise are shown to increase,
as expected.",0909.2680v1
2010-08-11,Gaussian approximation and single-spin measurement in OSCAR MRFM with spin noise,"A promising technique for measuring single electron spins is magnetic
resonance force microscopy (MRFM), in which a microcantilever with a permanent
magnetic tip is resonantly driven by a single oscillating spin. If the quality
factor of the cantilever is high enough, this signal will be amplified over
time to the point that it can be detected by optical or other techniques. An
important requirement, however, is that this measurement process occur on a
time scale short compared to any noise which disturbs the orientation of the
measured spin. We describe a model of spin noise for the MRFM system, and show
how this noise is transformed to become time-dependent in going to the usual
rotating frame. We simplify the description of the cantilever-spin system by
approximating the cantilever wavefunction as a Gaussian wavepacket, and show
that the resulting approximation closely matches the full quantum behavior. We
then examine the problem of detecting the signal for a cantilever with thermal
noise and spin with spin noise, deriving a condition for this to be a useful
measurement.",1008.2012v1
2011-01-18,Generating Entanglement and Squeezed States of Nuclear Spins in Quantum Dots,"Entanglement generation and detection are two of the most sought-after goals
in the field of quantum control. Besides offering a means to probe some of the
most peculiar and fundamental aspects of quantum mechanics, entanglement in
many-body systems can be used as a tool to reduce fluctuations below the
standard quantum limit. For spins, or spin-like systems, such a reduction of
fluctuations can be realized with so-called squeezed states. Here we present a
scheme for achieving coherent spin squeezing of nuclear spin states in
few-electron quantum dots. This work represents a major shift from earlier
studies in quantum dots, which have explored classical ""narrowing"" of the
nuclear polarization distribution through feedback involving stochastic spin
flips. In contrast, we use the nuclear-polarization-dependence of the electron
spin resonance (ESR) to provide a non-linearity which generates a non-trivial,
area-preserving, ""twisting"" dynamics that squeezes and stretches the nuclear
spin Wigner distribution without the need for nuclear spin flips.",1101.3370v2
2011-02-17,Designing spin-spin interactions with one and two dimensional ion crystals in planar micro traps,"We discuss the experimental feasibility of quantum simulation with trapped
ion crystals, using magnetic field gradients. We describe a micro structured
planar ion trap, which contains a central wire loop generating a strong
magnetic gradient of about 20 T/m in an ion crystal held about 160 \mu m above
the surface. On the theoretical side, we extend a proposal about spin-spin
interactions via magnetic gradient induced coupling (MAGIC) [Johanning, et al,
J. Phys. B: At. Mol. Opt. Phys. 42 (2009) 154009]. We describe aspects where
planar ion traps promise novel physics: Spin-spin coupling strengths of
transversal eigenmodes exhibit significant advantages over the coupling schemes
in longitudinal direction that have been previously investigated. With a chip
device and a magnetic field coil with small inductance, a resonant enhancement
of magnetic spin forces through the application of alternating magnetic field
gradients is proposed. Such resonantly enhanced spin-spin coupling may be used,
for instance, to create Schr\""odinger cat states. Finally we investigate
magnetic gradient interactions in two-dimensional ion crystals, and discuss
frustration effects in such two-dimensional arrangements.",1102.3645v2
2011-04-19,Spin relaxation mechanism in Silver nanowires covered with MgO protection layer,"Spin-flip mechanism in Ag nanowires with MgO surface protection layers has
been investigated by means of nonlocal spin valve measurements using
Permalloy/Ag lateral spin valves. The spin flip events mediated by surface
scattering are effectively suppressed by the MgO capping layer. The spin
relaxation process was found to be well described in the framework of
Elliott-Yafet mechanism and then the probabilities of spin-filp scattering for
phonon or impurity mediated momentum scattering is precisely determined in the
nanowires. The temperature dependent spin-lattice relaxation follows the
Bloch-Gr\""uneisen theory and falls on to a universal curve for the monovalent
metals as in the Monod and Beuneu scaling determined from the conduction
electron spin resonance data for bulk.",1104.3718v2
2011-05-13,Consistent interactions for high-spin fermion fields,"We address the issue of consistent interactions for off-shell fermion fields
of arbitrary spin. These interactions play a crucial role in the quantum
hadrodynamical description of high-spin baryon resonances in hadronic
processes. The Rarita-Schwinger description of high-spin fermion fields
involves unphysical degrees of freedom, associated with their lower-spin
content. These enter the interaction if not eliminated outright. The invariance
condition of the interaction under the unconstrained Rarita-Schwinger gauge
removes the lower-spin content of the fermion propagator and leads to a
consistent description of the interaction. We develop the most general,
consistent interaction structure for high-spin fermions. We find that the power
of the momentum dependence of a consistent interaction rises with the spin of
the fermion field. This leads to unphysical structures in the energy dependence
of the computed cross sections when the short-distance physics is cut off with
standard hadronic form factors. A novel, spin-dependent hadronic form factor is
proposed that suppresses the unphysical artifacts.",1105.2688v3
2011-09-03,Measurement of heavy-hole spin dephasing in (InGa)As quantum dots,"We measure the spin dephasing of holes localized in self-assembled (InGa)As
quantum dots by spin noise spectroscopy. The localized holes show a distinct
hyperfine interaction with the nuclear spin bath despite the p-type symmetry of
the valence band states. The experiments reveal a short spin relaxation time
{\tau}_{fast}^{hh} of 27 ns and a second, long spin relaxation time
{\tau}_{slow}^{hh} which exceeds the latter by more than one order of
magnitude. The two times are attributed to heavy hole spins aligned
perpendicular and parallel to the stochastic nuclear magnetic field. Intensity
dependent measurements and numerical simulations reveal that the long
relaxation time is still obscured by light absorption, despite low laser
intensity and large detuning. Off-resonant light absorption causes a
suppression of the spin noise signal due to the creation of a second hole
entailing a vanishing hole spin polarization.",1109.0610v2
2011-09-18,Nuclear Spin Dynamics of Ionized Phosphorus Donors in Silicon,"We demonstrate the coherent control and electrical readout of the nuclear
spins of ionized phosphorus donors in natural silicon. By combining pulsed
illumination with coherent electron spin manipulation, we selectively ionize
the donor depending on its nuclear spin state, exploiting a spin-dependent
recombination process via a spin pair at the Si/SiO2 interface. The
nuclear-spin coherence time of the ionized donor is 18 ms, two orders of
magnitude longer than in the neutral donor state, rendering the ionized donor a
potential resource as a quantum memory. The presented experimental techniques
allow for spectroscopy of ionized-donor nuclear spins, increase the sensitivity
of electrically detected electron nuclear double resonance by more than two
orders of magnitude, and give experimental access to the lifetime of parallel
electron spin pairs.",1109.3864v2
2011-11-15,Spin Coherence During Optical Excitation of a Single NV Center in Diamond,"We examine the quantum spin state of a single nitrogen-vacancy (NV) center in
diamond at room temperature as it makes a transition from the orbital
ground-state (GS) to the orbital excited-state (ES) during non-resonant optical
excitation. While the fluorescence read-out of NV-center spins relies on
conservation of the longitudinal spin projection during optical excitation, the
question of quantum phase preservation has not been examined. Using Ramsey
measurements and quantum process tomography, we establish limits on NV center
spin decoherence induced during optical excitation. Treating the optical
excitation and ES spin precession as a quantum process, we measure a process
fidelity of F=0.87\pm0.03, which includes ES spin dephasing during measurement.
Extrapolation to the moment of optical excitation yields F\approx0.95. This
result demonstrates that ES spin interactions may be used as a resource for
quantum control because the quantum spin state can survive incoherent orbital
transitions.",1111.3687v1
2012-03-26,Measuring central-spin interaction with a spin bath by pulsed ENDOR: Towards suppression of spin diffusion decoherence,"We present pulsed electron-nuclear double resonance (ENDOR) experiments which
enable us to characterize the coupling between bismuth donor spin qubits in Si
and the surrounding spin bath of 29Si impurities which provides the dominant
decoherence mechanism (nuclear spin diffusion) at low temperatures (< 16 K).
Decoupling from the spin bath is predicted and cluster correlation expansion
simulations show near-complete suppression of spin diffusion, at optimal
working points. The suppression takes the form of sharply peaked divergences of
the spin diffusion coherence time, in contrast with previously identified
broader regions of insensitivity to classical fluctuations. ENDOR data suggest
that anisotropic contributions are comparatively weak, so the form of the
divergences is largely independent of crystal orientation.",1203.5607v4
2012-04-29,Sensing remote nuclear spins,"Sensing single nuclear spins is a central challenge in magnetic resonance
based imaging techniques. Although different methods and especially diamond
defect based sensing and imaging techniques in principle have shown sufficient
sensitivity, signals from single nuclear spins are usually too weak to be
distinguished from background noise. Here, we present the detection and
identification of remote single C-13 nuclear spins embedded in nuclear spin
baths surrounding a single electron spins of a nitrogen-vacancy centre in
diamond. With dynamical decoupling control of the centre electron spin, the
weak magnetic field ~10 nT from a single nuclear spin located ~3 nm from the
centre with hyperfine coupling as weak as ~500 Hz is amplified and detected.
The quantum nature of the coupling is confirmed and precise position and the
vector components of the nuclear field are determined. Given the distance over
which nuclear magnetic fields can be detected the technique marks a firm step
towards imaging, detecting and controlling nuclear spin species external to the
diamond sensor.",1204.6513v1
2013-02-19,Optical spin orientation and depolarization in Ge,"Optical spin orientation and depolarization phenomena in semiconductors are
of overwhelming importance for the development of spin-optoelectronics. In this
paper we employ Ge-based spin-photodiodes to investigate the room temperature
spectral dependence of optical spin orientation in Germanium, in the range
400-1550 nm, and the photo-carrier spin relaxation phenomena. Apart from the
maximum in the spin polarization of photo-carriers for photon energy resonant
with the direct gap (1550 nm), we experimentally demonstrate the presence of a
second sizable peak at 530 nm due to photo-generation far away from the center
of the Brillouin zone, within the L valleys. Furthermore, our data indicate
that the equivalent the spin lifetime of holes in Ge is in the order of 5-10
ps, meaning that the spin diffusion length for holes at room temperature is
larger than expected, in the order of 150-220 nm.",1302.4675v1
2013-02-27,Optimization of the yttrium iron garnet/platinum interface for spin pumping-based applications,"The dependence of the spin pumping efficiency and the spin mixing conductance
on the surface processing of yttrium iron garnet (YIG) before the platinum (Pt)
deposition has been investigated quantitatively. The ferromagnetic resonance
driven spin pumping injects a spin polarized current into the Pt layer, which
is transformed into an electromotive force by the inverse spin Hall effect. Our
experiments show that the spin pumping effect indeed strongly depends on the
YIG/Pt interface condition. We measure an enhancement of the inverse spin Hall
voltage and the spin mixing conductance of more than two orders of magnitude
with improved sample preparation.",1302.6697v1
2013-06-11,Decay of spin coherences in one-dimensional spin systems,"Strategies to protect multi-qubit states against decoherence are difficult to
formulate because of their complex many-body dynamics. A better knowledge of
the decay dynamics would help in the construction of decoupling control
schemes. Here we use solid-state nuclear magnetic resonance techniques to
experimentally investigate the decay of coherent multi-spin states in linear
spin chains. Leveraging on the quasi-one-dimensional geometry of Fluorapatite
crystal spin systems, we can gain a deeper insight on the multi-spin states
created by the coherent evolution, and their subsequent decay, than it is
possible in 3D systems. We are then able to formulate an analytical model that
captures the key features of the decay. We can thus compare the decoherence
behavior for different initial states of the spin chain and link their decay
rate to the state characteristics, in particular their coherence and long-range
correlation among spins. Our experimental and theoretical study shows that the
spin chains undergo a rich dynamics, with a slower decay rate than for the 3D
case, and thus might be more amenable to decoupling techniques.",1306.2620v1
2014-03-03,Faraday rotation echo spectroscopy and detection of quantum fluctuations,"Central spin decoherence is useful for detecting many-body physics in
environments and moreover, the spin echo control can remove the effects of
static thermal fluctuations so that the quantum fluctuations are revealed. The
central spin decoherence approach, however, is feasible only in some special
configurations and often requires uniform coupling between the central spin and
individual spins in the baths, which are very challenging in experiments. Here,
by making analogue between central spin decoherence and depolarization of
photons, we propose a scheme of Faraday rotation echo spectroscopy (FRES) for
studying quantum fluctuations in interacting spin systems. The echo control of
the photon polarization is realized by flipping the polarization with a
birefringence crystal. The FRES, similar to spin echo in magnetic resonance
spectroscopy, can suppress the effects of the static magnetic fluctuations and
therefore reveal dynamical magnetic fluctuations. We apply the scheme to a
rare-earth compound LiHoF4 and calculate the echo signal, which is related to
the quantum fluctuations of the system. We observe enhanced signals at the
phase boundary. The FRES should be useful for studying quantum fluctuations in
a broad range of spin systems, including cold atoms, quantum dots, solid-state
impurities, and transparent magnetic materials.",1403.0420v1
2014-03-27,Resonant optical control of the electrically-induced spin polarization by periodic excitation,"We show that the electron spin polarization generated by an electrical
current may have its direction controlled and magnitude amplified by periodic
optical excitation. The electrical and optical spin control methods were
combined and implemented in a two-dimensional electron gas. By Kerr rotation in
an external transverse magnetic field, we demonstrate unexpected long-lived
coherent spin oscillations of the current-induced signal in a system with large
spin-orbit interaction. Using a single linearly polarized pulse for spin
manipulation and detection, we found a strong dependence on the pulse optical
power and sample temperature indicating the relevance of the hole spin in the
electron spin initialization. The signal was mapped in a Hall bar as function
of the position relative to the injection contact. Finally, the presence of an
in-plane spin polarization was directly verified by rotating the experimental
geometry.",1403.7176v2
2014-04-23,Semiclassical spin-spin dynamics and feedback control in transport through a quantum dot,"We present a theory of magnetotransport through an electronic orbital, where
the electron spin interacts with a (sufficiently) large external spin via an
exchange interaction. Using a semiclassical approximation, we derive a set of
equations of motions for the electron density matrix and the mean value of the
external spin that turns out to be highly nonlinear. The dissipation via the
electronic leads is implemented in terms of a quantum master equation that is
combined with the nonlinear terms of the spin-spin interaction. With an
anisotropic exchange coupling a variety of dynamics is generated, such as
self-sustained oscillations with parametric resonances or even chaotic
behavior. Within our theory we can integrate a Maxwell-demon-like closed-loop
feedback scheme that is capable of transporting particles against an applied
bias voltage and that can be used to implement a spin filter to generate
spin-dependent oscillating currents of opposite directions.",1404.5831v3
2014-05-07,Probing individual split Cooper-pairs using the spin qubit toolkit,"A superconductor is a natural source of spin-entangled spatially separated
electron pairs. Although the first Cooper-pair splitter devices have been
realized recently, an experimental confirmation of the spin state and the
entanglement of the emitted electron pairs is lacking up to now. In this paper
a method is proposed to confirm the spin-singlet character of individual split
Cooper pairs. Two quantum dots (QDs), each of them holding one spin-prepared
electron, serve as the detector of the spin state of a single Cooper pair that
is forced to split when it tunnels out from the superconductor to the QDs. The
number of charges on the QDs, measured at the end of the procedure, carries
information on the spin state of the extracted Cooper pair. The method relies
on the experimentally established toolkit of QD-based spin qubits: resonant
spin manipulation, Pauli blockade, and charge measurement.",1405.1567v1
2014-10-22,Spin current generation from sputtered Y3Fe5O12 films,"Spin current injection from sputtered yttrium iron garnet (YIG) films into an
adjacent platinum layer has been investigated by means of the spin pumping and
the spin Seebeck effects. Films with a thickness of 83 and 96 nanometers were
fabricated by on-axis magnetron rf sputtering at room temperature and
subsequent post-annealing. From the frequency dependence of the ferromagnetic
resonance linewidth, the damping constant has been estimated to be
$(7.0\pm1.0)\times 10^{-4}$. Magnitudes of the spin current generated by the
spin pumping and the spin Seebeck effect are of the same order as values for
YIG films prepared by liquid phase epitaxy. The efficient spin current
injection can be ascribed to a good YIG|Pt interface, which is confirmed by the
large spin-mixing conductance $(2.0\pm0.2)\times 10^{18}$ m$^{-2}$.",1410.5987v1
2014-11-12,Dependence of the Efficiency of Spin Hall Torque on the Transparency of Pt-Ferromagnetic Layer Interfaces,"We report that spin current transport across Pt-ferromagnet (FM) interfaces
is strongly dependent on the type and the thickness of the FM layer and on
post-deposition processing protocols. By employing both harmonic voltage
measurements and spin-torque ferromagnetic resonance measurements, we find that
the efficiency of the Pt spin Hall effect in exerting a damping-like spin
torque on the FM ranges from < 0.05 to > 0.10 under different interfacial
conditions. We also show that the temperature dependence of the spin torque
efficiencies for both the damping-like torque and field-like torque is
dependent upon the details of the Pt-FM interface. The ""internal"" spin Hall
angle of the Pt thin films used in this study, after taking the interfacial
spin transmission factor into account, is estimated to be ~ 0.20. This suggests
that a careful engineering of Pt-FM interfaces can improve the spin-Hall-torque
efficiency of Pt-based spintronic devices.",1411.3379v1
2014-11-19,Dynamical spin injection at a quasi-one-dimensional ferromagnet-graphene interface,"We present a study of dynamical spin injection from a three-dimensional
ferromagnet into two-dimensional single-layer graphene. Comparative
ferromagnetic resonance (FMR) studies of ferromagnet/graphene strips buried
underneath the central line of a coplanar waveguide show that the FMR linewidth
broadening is the largest when the graphene layer protrudes laterally away from
the ferromagnetic strip, indicating that the spin current is injected into the
graphene areas away from the area directly underneath the ferromagnet being
excited. Our results confirm that the observed damping is indeed a signature of
dynamical spin injection, wherein a pure spin current is pumped into the
single-layer graphene from the precessing magnetization of the ferromagnet. The
observed spin pumping efficiency is difficult to reconcile with the expected
backflow of spins according to the standard spin pumping theory and the
characteristics of graphene, and constitutes an enigma for spin pumping in
two-dimensional structures.",1411.5339v2
2015-03-26,Longitudinal and transversal spin dynamics of donor-bound electrons in fluorine-doped ZnSe: spin inertia versus Hanle effect,"The spin dynamics of the strongly localized, donor-bound electrons in
fluorine-doped ZnSe epilayers is studied by pump-probe Kerr rotation
techniques. A method exploiting the spin inertia is developed and used to
measure the longitudinal spin relaxation time, $T_1$, in a wide range of
magnetic fields, temperatures, and pump densities. The $T_1$ time of the
donor-bound electron spin of about 1.6 $\mu$s remains nearly constant for
external magnetic fields varied from zero up to 2.5 T (Faraday geometry) and in
a temperature range $1.8-45$ K. The inhomogeneous spin dephasing time,
$T_2^*=8-33$ ns, is measured using the resonant spin amplification and Hanle
effects under pulsed and steady-state pumping, respectively. These findings
impose severe restrictions on possible spin relaxation mechanisms.",1503.07684v1
2016-08-01,Extended pump-probe Faraday rotation spectroscopy of the submicrosecond electron spin dynamics in n-type GaAs,"We develop an extended pump-probe Faraday rotation technique to study the
submicrosecond electron spin dynamics with picosecond time resolution in a wide
range of magnetic fields. The electron spin dephasing time $T_2^*$ and the
longitudinal spin relaxation time $T_1$, both approaching $250$ ns in weak
fields, are measured thereby in $n$-type bulk GaAs. By tailoring the pump pulse
train through increasing the contained number of pulses, the buildup of
resonant spin amplification is demonstrated for the electron spin polarization.
The spin precession amplitude in high magnetic fields applied in the Voigt
geometry shows a non-monotonic dynamics deviating strongly from a
mono-exponential decay and revealing slow beatings. The beatings indicate a two
spin component behavior with a $g$-factor difference of $\Delta g \sim
4\times10^{-4}$, much smaller than the $\Delta g$ expected for free and
donor-bound electrons. This $g$-factor variation indicates efficient, but
incomplete spin exchange averaging.",1608.00314v4
2016-09-24,Field-like spin orbit torque in ultra-thin polycrystalline FeMn films,"Field-like spin orbit torque in FeMn/Pt bilayers with ultra-thin
polycrystalline FeMn has been characterized through planar Hall effect
measurements. A large effective field is obtained for FeMn in the thickness
range of 2 to 5 nm. The experimental observations can be reasonably accounted
for by using a macro-spin model under the assumption that the FeMn layer is
composed of two spin sublattices with unequal magnetizations. The large
effective field corroborates the spin Hall origin of the effective field
considering the much smaller uncompensated net moments in FeMn as compared to
NiFe. The effective absorption of spin current by FeMn is further confirmed by
the fact that spin current generated by Pt in NiFe/FeMn/Pt trilayers can only
travel through the FeMn layer with a thickness of 1 to 4 nm. By quantifying the
field-like effective field induced in NiFe, a spin diffusion length of 2 nm is
estimated in FeMn, in consistence with values reported in literature by
ferromagnetic resonance and spin-pumping experiments.",1609.07564v1
2016-10-22,Enhanced spin-orbit torque via modulation of spin current absorption,"The magnitude of spin-orbit torque (SOT), exerted to a ferromagnet (FM) from
an adjacent heavy metal (HM), strongly depends on the amount of spin currents
absorbed in the FM. We exploit the large spin absorption at the Ru interface to
manipulate the SOTs in HM/FM/Ru multilayers. While the FM thickness is smaller
than its spin dephasing length of 1.2 nm, the top Ru layer largely boosts the
absorption of spin currents into the FM layer and substantially enhances the
strength of SOT acting on the FM. Spin-pumping experiments induced by
ferromagnetic resonance support our conclusions that the observed increase in
the SOT efficiency can be attributed to an enhancement of the spin-current
absorption. A theoretical model that considers both reflected and transmitted
mixing conductances at the two interfaces of FM is developed to explain the
results.",1610.06989v1
2017-07-09,Nuclear spin cooling by helicity-alternated optical pumping at weak magnetic fields in $n$-GaAs,"The spin dynamics of localized donor-bound electrons interacting with the
nuclear spin ensemble in $n$-doped GaAs epilayers is studied using nuclear spin
polarization by light with modulated circular polarization. We show that the
observed build-up of the nuclear spin polarization is a result of competition
between nuclear spin cooling and nuclear spin warm-up in the oscillating Knight
field. The developed model allows us to explain the dependence of nuclear spin
polarization on the modulation frequency and to estimate the equilibration time
of the nuclear spin system that appears to be shorter than the transverse
relaxation time $T_2$ determined from nuclear magnetic resonance.",1707.02658v2
2017-09-18,"Spin-selectable, region-tunable negative differential resistance in graphene double ferromagnetic barriers","We propose a graphene device that can generate spin-dependent negative
differential resistance (NDR). The device is composed of a sufficiently wide
and short graphene and two gated EuO strips deposited on top of it. This scheme
avoids graphene edge tailors required by previous proposals. More importantly,
we find clear significant of a spin selectivity and a region tunability in the
spin-dependent NDR: by changing the top gates of the device, NDR for spin up
only, spin down only, or both spins (occurring sequentially) can be
respectively realized; meanwhile, the central position of the NDR region in
each case can be monotonously tuned in a wide range of bias voltage. These
remarkable features are attributed to a gate controllability of the
spin-dependent resonant levels in the device hence their deviations from the
Fermi energy and Dirac point in the source electrode, respectively. They add a
spin and a bias degree of freedom to conventional NDR-based devices, which
paves a way for designing a whole new class of NDR circuits.",1709.06038v2
2018-06-08,Optically-detected long-lived spin coherence in multilayer systems: Double and triple quantum wells,"In this contribution, we investigated the spin coherence of high-mobility
dense two-dimensional electron gases confined in multilayer systems. The
dynamics of optically-induced spin polarization was experimentally studied
employing the time-resolved Kerr rotation and resonant spin amplification
techniques. For both the double and triple quantum wells doped beyond the
metal-insulator transition, where the spin coherence is greatly suppressed, we
found remarkably long spin lifetimes limited by the Dyakonov-Perel mechanism
and spin hopping process between the donor sites as well as the spread of
ensemble g-factor. The double quantum well structure yields a spin lifetime of
6.25 ns at T = 5 K while the triple quantum well shows a spin lifetime
exceeding 25 ns at T = 8 K.",1806.03092v1
2018-10-26,Superfluid Transport in Quantum Spin Chains,"Spin superfluids enable long-distance spin transport through classical
ferromagnets by developing topologically stable magnetic textures. For small
spins at low dimensions, however, the topological protection suffers from
strong quantum fluctuations. We study the remanence of spin superfluidity
inherited from the classical magnet by considering the two-terminal spin
transport through a finite spin-1/2 magnetic chain with planar exchange. By
fermionizing the system, we recast the spin-transport problem in terms of
quasiparticle transmission through a superconducting region. We show that the
topological underpinnings of a semiclassical spin superfluid relate to the
topological superconductivity in the fermionic representation. In particular,
we find an efficient spin transmission through the magnetic region of a
characteristic resonant length, which can be related to the properties of the
boundary Majorana zero modes.",1810.11470v1
2019-06-07,Angle resolved relaxation of spin currents by antiferromagnets in spin valves,"We observe and analyze tunable relaxation of a pure spin current by an
antiferromagnet in spin-valves. This is achieved by carefully controlling the
angle between a resonantly excited ferromagnetic layer pumping the spin current
and the N\'eel vector of the antiferromagnetic layer. The effect is observed as
an angle-dependent spin-pumping contribution to the ferromagnetic resonance
linewidth. An interplay between spin-mixing conductance and, often disregarded,
longitudinal spin conductance is found to underlie our observations, which is
in agreement with a recent prediction for related ferromagnetic spin valves.",1906.03124v3
2020-04-17,Spectroscopic signatures of next-nearest-neighbor hopping in the charge and spin dynamics of doped one-dimensional antiferromagnets,"We study the impact of next-nearest-neighbor (nnn) hopping on the low-energy
collective excitations of strongly correlated doped antiferromagnetic cuprate
spin chains. Specifically, we use exact diagonalization and the density matrix
renormalization group method to study the single-particle spectral function,
the dynamical spin and charge structure factors, and the Cu $L$-edge resonant
inelastic x-ray scattering (RIXS) intensity of the doped $t$-$t^\prime$-$J$
model for a set of $t^\prime$ values. We find evidence for the breakdown of
spin-charge separation as $|t^\prime|$ increases and identify its fingerprints
in the dynamical response functions. The inclusion of nnn hopping couples the
spinon and holon excitations, resulting in the formation of a spin-polaron,
where a ferromagnetic spin polarization cloud dresses the doped carrier. The
spin-polaron manifests itself as additional spectral weight in the dynamical
correlation functions, which appear simultaneously in the spin- and
charge-sensitive channels. We also demonstrate that RIXS can provide a unique
view of the spin-polaron, due to its sensitivity to both the spin and charge
degrees of freedom.",2004.08435v1
2020-04-20,"Optical detection of electron spin dynamics driven by fast variations of a magnetic field: a simple method to measure $T_1$, $T_2$, and $T_2^*$ in semiconductors","We develop a simple method for measuring the electron spin relaxation times
$T_1$, $T_2$ and $T_2^*$ in semiconductors and demonstrate its exemplary
application to $n$-type GaAs. Using an abrupt variation of the magnetic field
acting on electron spins, we detect the spin evolution by measuring the Faraday
rotation of a short laser pulse. Depending on the magnetic field orientation,
this allows us to measure either the longitudinal spin relaxation time $T_1$ or
the inhomogeneous transverse spin dephasing time $T_2^*$. In order to determine
the homogeneous spin coherence time $T_2$, we apply a pulse of an oscillating
radiofrequency (rf) field resonant with the Larmor frequency and detect the
subsequent decay of the spin precession. The amplitude of the rf-driven spin
precession is significantly enhanced upon additional optical pumping along the
magnetic field.",2004.09408v1
2016-03-02,Spin Manipulation in Graphene by Chemically-Induced Sublattice Pseudospin Polarization,"Spin manipulation is one of the most critical challenges to realize
spin-based logic devices and spintronic circuits. Graphene has been heralded as
an ideal material to achieve spin manipulation but so far new paradigms and
demonstrators are limited. Here we show that certain impurities such as
fluorine ad-atoms, which locally break sublattice symmetry without the
formation of strong magnetic moment, could result in a remarkable variability
of spin transport characteristics. The impurity resonance level is found to be
associated with a long range sublattice pseudospin polarization, which by
locally decoupling spin and pseudospin dynamics, provokes a huge spin lifetime
electron-hole asymmetry. In the dilute impurity limit, spin lifetimes could be
tuned electrostatically from hundred picoseconds to several nanoseconds,
providing a protocol to chemically engineer an unprecedented spin device
functionality.",1603.00834v1
2016-12-14,How to control Spin-Seebeck current in a metal-quantum dot-magnetic insulator junction,"The control of the spin-Seebeck current is still a challenging task for the
development of spin caloritronic devices. Here, we construct a spin-Seebeck
device by inserting a strongly correlated quantum dot (QD) between the metal
lead and magnetic insulator. Using the slave-particle approach and non-crossing
approximation, we find that the spin-Seebeck effect increases significantly
when the energy level of the QD locates near the Fermi level of the metal lead
due to the enhancement of spin flipping and occurrences of quantum resonance.
Since this can be easily realized by applying a gate voltage in experiments,
the spin-Seebeck device proposed here can also work as a thermovoltaic
transistor. Moreover, the optimal correlation strength and the energy level
position of the QD are discussed to maximize the spin-Seebeck current as
required for applications in controllable spin caloritronic devices.",1612.05595v1
2016-12-29,Spin-Pairing Correlations and Spin Polarization of Majorana Bound States in Two-Dimensional Topological Insulator Systems,"We demonstrate that zero-energy Majorana bound state, in the ferromagnetic
insulator (FI)-superconductor (SC) junction formed on the edge of
two-dimensional topological insulator, exhibits three types of spin-triplet
pairing correlations and its spin polarization direction is position
independent in ferromagnetic insulator. When an electron is injected with a
spin (anti-)parallel to this direction, equal-spin Andreev reflection exhibits
the widest (narrowest) resonance peak. Similar behaviour is found when the
coupling between two Majorana bound states in a FI-SC-FI junction is invoked,
though an additional weak spin-singlet pairing correlation is generated. These
signatures can readily facilitate the experimental detection of spin-triplet
correlations and spin polarization of Majorana bound states.",1612.09127v1
2020-09-11,Spin entanglement via STM current,"We consider a system of two spins under a scanning tunneling microscope bias
and derive its master equation. We find that the tunneling elements to the
electronic contacts (tip and substrate) generate an exchange interaction
between the spins, as well as a Dzyaloshinskii-Moriya interaction in the
presence of spin-orbit coupling. The tunnel current spectrum then shows
additional lines compared to conventional spin resonance experiments. When the
spins have degenerate Larmor frequencies and equal tunneling amplitudes
(without spin-orbit), there is a dark state with vanishing decay rate. The
coupling to the electronic environment generates significant spin-spin
entanglement via the dark state, even if the initial state is non-entangled.",2009.05452v2
2020-11-03,Intensity equations for birefringent spin lasers,"Semiconductor spin lasers are distinguished from their conventional
counterparts by the presence of spin-polarized carriers. The transfer of
angular momentum of the spin-polarized carriers to photons provides important
opportunities for the operation of lasers. With the injection of spin-polarized
carriers, which lead to the circularly polarized light, the polarization of the
emitted light can be changed an order of magnitude faster than its intensity.
This ultrafast operation of spin lasers relies on a large birefringence,
usually viewed as detrimental in spin and conventional lasers. We introduce a
transparent description of spin lasers using intensity equations, which
elucidate the influence of birefringence on the intensity and polarization
modulation of lasers. While intensity modulation is independent of
birefringence, for polarization modulation an increase in birefringence
directly increases the resonant frequency. Our results for dynamical operation
of lasers provide a guide for their spin-dependent response and spintronic
applications beyond magnetoresistance.",2011.01486v1
2021-02-24,Realization of exciton-mediated optical spin-orbit interaction in organic microcrystalline resonators,"The ability to control the spin-orbit interaction of light in optical
microresonators is of fundamental importance for future photonics. Organic
microcrystals, due to their giant optical anisotropy, play a crucial role in
spin-optics and topological photonics. Here we realize controllable and
wavelength-dependent Rashba-Dresselhaus spin-orbit interaction, attributed to
the anisotropic excitonic response in an optical microcavity filled with an
organic microcrystalline. We also investigate the transition of the spin-orbit
interaction from dominant photonic type caused by the splitting of the
transverse-electric and transverse-magnetic modes to spin-orbit interaction of
the Rashba-Dresselhaus type. The interplay of the two allows us to engineer the
spin-orbit interaction of light in organic microcavities, which besides its
fundamental interest promises applications in spin-controlled on-chip
integrated nanophotonic elements, towards exploiting non-magnetic and low-cost
spin-photonic devices.",2102.12200v1
2021-08-03,Atomic scale control of spin current transmission at interfaces,"Spin transmission at ferromagnet/heavy metal interfaces is of vital
importance for many spintronic devices. Usually the spin current transmission
is limited by the spin mixing conductance and loss mechanisms such as spin
memory loss. In order to understand these effects, we study the interface
transmission when an insulating interlayer is inserted between the ferromagnet
and the heavy metal. For this we measure the inverse spin Hall voltage
generated from optically injected spin current pulses as well as the magnitude
of the spin pumping using ferromagnetic resonance. From our results we conclude
that significant spin memory loss only occurs for 5d metals with less than half
filled d-shell.",2108.01770v1
2017-01-02,Important role of magnetization precession angle measurement in inverse spin Hall effect induced by spin pumping,"Here, we investigate spin Hall angle of Pt in Ni80Fe20/Pt bilayer system by
using a broadband spin pumping and inverse spin Hall effect measurement. An
out-of-plane excitation geometry with application of external magnetic field
perpendicular to the charge current direction is utilized in order to suppress
unwanted galvanomagnetic effects. Magnetization precession angle on
ferromagnetic resonance for wide excitation frequency range (4-14 GHz) is
estimated from the rectification voltage of anisotropic magnetoresistance (AMR)
and a conventional method of using microwave power in a coplanar waveguide. A
marked difference in the precession angle profiles for the different methods is
observed, resulting in the large variation in estimated values of spin current
density at Ni80Fe20/Pt interface. The frequency dependence of the spin current
density estimated using AMR effect is found to be similar to that of the
inverse spin Hall voltage. We obtain the frequency-invariant spin Hall angle of
0.067.",1701.00412v1
2017-01-24,Coherent control of the silicon-vacancy spin in diamond,"Spin impurities in diamond have emerged as a promising building block in a
wide range of solid-state-based quantum technologies. The negatively charged
silicon-vacancy centre combines the advantages of its high-quality photonic
properties with a ground-state electronic spin, which can be read out
optically. However, for this spin to be operational as a quantum bit, full
quantum control is essential. Here, we report the measurement of optically
detected magnetic resonance and the demonstration of coherent control of a
single silicon-vacancy centre spin with a microwave field. Using Ramsey
interferometry, we directly measure a spin coherence time, T2*, of 115 +/- 9 ns
at 3.6 K. The temperature dependence of coherence times indicates that
dephasing and decay of the spin arise from single phonon-mediated excitation
between orbital branches of the ground state. Our results enable the
silicon-vacancy centre spin to become a controllable resource to establish
spin-photon quantum interfaces.",1701.06848v1
2019-08-14,Quantum trajectories in spin-exchange collisions reveal the nature of spin-noise correlations in multi-species alkali vapors,"Spin-exchange collisions in alkali vapors have been at the basis of several
fundamental and applied investigations, like nuclear structure studies and
tests of fundamental symmetries, ultra-sensitive atomic magnetometers, magnetic
resonance and bio-magnetic imaging. Spin-exchange collisions cause loss of spin
coherence, and concomittantly produce spin noise, both phenomena being central
to quantum metrology. We here develop the quantum trajectory picture of
spin-exchange collisions, consistent with their long-standing ensemble
description using density matrices. We then use quantum trajectories to reveal
the nature of spin-noise correlations that spontaneously build up in
multi-species atomic vapors, frequently utilized in the most sensitive spin
measurements.",1908.05194v3
2020-06-10,Atomic-scale spin-polarization maps using functionalized superconducting probes,"A scanning tunneling microscope (STM) with a magnetic tip that has a
sufficiently strong spin-polarization can be used to map the sample's spin
structure down to the atomic scale but usually lacks the possibility to
absolutely determine the value of the sample's spin-polarization. Magnetic
impurities in superconducting materials give rise to pairs of perfectly, i.e.
100% spin-polarized sub-gap resonances. In this work, we functionalize the apex
of a superconducting Nb STM-tip with such impurity states by attaching Fe atoms
to probe the spin-polarization of atom-manipulated Mn nanomagnets on a Nb(110)
surface. By comparison with spin-polarized STM measurements of the same
nanomagnets using Cr bulk tips we demonstrate an extraordinary spin-sensitivity
and the possibility to measure the sample's spin-polarization values
quantitatively with our new functionalized probes.",2006.05770v1
2020-06-29,Electronic charge transfer driven by spin cycloidal structure,"Muon spin rotation and resonant soft X-ray scattering experiments on
prototype multiferroics RMn2O5 (R = Y, Sm) are used to demonstrate that the
local electric displacements are driven by the spin-current (SC) mechanism.
Small local electric displacements were evaluated by observing spin
polarization at ligand O ions, for which implanted muons served as an extremely
sensitive probe. Our results for YMn2O5 provide evidence that the spin
polarization of O ions forming a spin cycloid chain with Mn spins increases in
proportion to the vector spin chirality (Si x Sj ) of the Mn ions. This
relationship strongly indicates that the charge transfer between O and Mn ions
is driven by the SC mechanism, which leads to the ferroelectricity accompanying
O spin polarization.",2006.15834v2
2021-12-16,Towards exact predictions of spin-phonon relaxation times: an ab initio implementation of open quantum systems theory,"Spin-phonon coupling is the main drive of spin relaxation and decoherence in
solid-state semiconductors at finite temperature. Controlling this interaction
is a central problem for many disciplines, ranging from magnetic resonance to
quantum technologies. Spin relaxation theories have been developed for almost a
century but often employ a phenomenological description of phonons and their
coupling to spin, resulting in a non-predictive tool and hindering our detailed
understanding of spin dynamics. Here we combine fourth-order time-local quantum
master equations with advanced electronic structure methods and perform
predictions of spin-phonon relaxation time for a series of solid-state
coordination compounds based on both transition metals and lanthanide Kramers
ions. The agreement between experiments and simulations demonstrates that an
accurate, universal and fully ab initio implementation of spin relaxation
theory is possible, thus paving the way to a systematic study of spin-phonon
relaxation in solid-state materials.",2112.09236v1
2022-02-18,"Electron spins interaction in the spin-Peierls phase of the organic spin chain (o -DMTTF) 2 X (X = Cl, Br, I)","We investigate the electron spin resonance of the organic spin-Peierls chain
(o-DMTTF)2X with X = Cl, Br and I. We describe the temperature dependence of
the spin gap during the phase transition and quantify the dimerization
parameter $\delta$. At the lowest temperatures, the susceptibility is governed
by defects in the spin dimerized chain. Such strongly correlated defects are
the consequence of breaks in the translational symmetry of the chain. In the
vicinity of the defects the spins are polarized antiferomagnetically forming a
magnetic soliton: a spin 1 2 quasi-particle of size ruled by $\delta$ pinned to
the defects. For (o-DMTTF)2Br and (o-DMTTF)2Cl, we show that the one-half of
the total number of solitons are in isolation (as singles) whereas the other
half form pairs (soliton dimers)with a strong magnetic coupling. The Rabi
oscillations of both the single-soliton and the soliton-dimer are observed,
which is a prerequisite in the context of quantum information.",2202.09071v1
2022-03-26,Nonequilibrium dynamics in a spin valve with noncollinear magnetization,"We utilize a hybrid quantum-classical equation of motion approach to
investigate the spin dynamics and spin-transfer torque in a spin valve under
bias voltage. We show that the interplay between localized classical magnetic
moments and conduction electrons induces a complex effective exchange coupling
between the magnetic layers. This leads to a declination of magnetizations from
layers anisotropy axes even in equilibrium. Introducing a finite bias voltage
triggers spin currents and related spin-transfer torques which further tilt the
magnetizations and govern the relaxation processes of the spin dynamics.
Analyzing different scenarios of the applied bias voltage, we show that
symmetric and asymmetric voltage drops can lead to relaxation times of the spin
dynamics that differ by several orders of magnitude at comparable charge
currents. In both cases we observe resonant features, where the relaxation is
boosted whenever the chemical potential of the leads matches the maxima in the
density of the states of the spin-valve electrons.",2203.14068v2
2022-04-04,Inverse Orbital Torque via Spin-Orbital Entangled States,"While current-induced torque by orbital current has been experimentally found
in various structures, evidence for its reciprocity has been missing so far.
Here, we report experimental evidence of strong inverse orbital torque in
YIG/Pt/CuOx (YIG = Y3Fe5O12) mediated by spin-orbital entangled electronic
states in Pt. By injecting spin current from YIG to Pt by the spin pumping via
ferromagnetic resonance and by the spin Seebeck effect, we find a pronounced
inverse spin Hall effect-like signal. While a part of the signal is explained
as due to the inverse spin-orbital Hall effect in Pt, we also find substantial
increase of the signal in YIG/Pt/CuOx structures compared to the signal in
YIG/Pt. We attribute this to the inverse orbital Rashba-Edelstein effect at
Pt/CuOx interface mediated by the spin-orbital entangled states in Pt. Our work
paves the way toward understanding of spin-orbital entangled physics in
nonequilibrium and provides a way for electrical detection of the orbital
current in orbitronic device applications.",2204.01825v2
2022-09-25,Suppressing the decoherence of alkali-metal spins at low magnetic fields,"Interactions of electron spins with rotational degrees of freedom during
collisions or with external fields are fundamental processes that limit the
coherence time of spin gases. We experimentally study the decoherence of warm
cesium spins dominated by spin rotation-interaction during binary collisions
with N$_2$ molecules or by absorption of near-resonant light. We report an
order of magnitude suppression of the spin decoherence rate by either of those
processes at low magnetic fields. We find that the excess decoherence at higher
magnetic fields originates from an asynchronous Larmor precession, which is a
mechanism that universally affects all alkali atoms, and can yet be suppressed
at low magnetic-fields. This work extends the widely-used regime of
Spin-Exchange Relaxation Free (SERF), which provides protection from
decoherence by random spin-conservative processes, now for random processes
which do not conserve but rather destruct electron spins.",2209.12236v1
2023-05-16,Terahertz spin conductance probes of coherent and incoherent spin tunneling through MgO tunnel junctions,"We study femtosecond spin currents through MgO tunneling barriers in CoFeB(2
nm)|MgO($d$)|Pt(2 nm) stacks by terahertz emission spectroscopy. To obtain
transport information independent of extrinsic experimental factors, we
determine the complex-valued spin conductance $\tilde{G}_d (\omega)$ of the MgO
layer (thickness d= 0-6 {\AA} over a wide frequency range $(\omega/2\pi=$ 0.5-8
THz). In the time $(t)$ domain,$ G_d (t)$ has an instantaneous and delayed
component that point to (i) spin transport through Pt pinholes in MgO, (ii)
coherent spin tunneling and (iii) incoherent resonant spin tunneling mediated
by defect states in MgO. A remarkable signature of (iii) is its relaxation time
that grows monotonically with $d$ to as much as 270 fs at $d= 6$ {\AA}, in full
agreement with an analytical model. Our results indicate that terahertz spin
conductance spectroscopy will yield new and relevant insights into ultrafast
spin transport for a wide range of materials.",2305.09074v2
2023-06-14,Coherent scattering from coupled two level systems,"We study the resonance fluorescence properties of an optically active spin
1/2 system, elucidating the effects of a magnetic field on the coherence of the
scattered light. We derive a master equation model for this system that
reproduces the results of a two level system (TLS) while also being applicable
to a spin system with ground state coupling. This model is then solved
analytically in the weak excitation regime. The inclusion of spin dynamics in
our model alters the properties of the coherently scattered light at a
fundamental level. For a TLS the coherence properties are known to be
determined by the input laser. We show that spin scattered light inherits the
coherence properties of the spin. This mapping allows us to measure spin
dynamics and coherence time through direct measurement of the scattered fields.
Furthermore, we show the ability to resolve sub-natural linewidth zeeman
splittings. Along with representing an invaluable tool for spin spectroscopy
understanding the coherence properties of the spin-scattered field will be
vital for spin-photon based quantum technologies.",2306.08439v1
2023-08-30,Magnetization and Polarization of Coupled Nuclear Spin Ensembles,"In magnetic resonance, the bulk magnetization of a sample that is being
measured is typically defined as a quantity proportional to spin polarization.
The fact that all spins of the same type contribute equally to measurable
signals is considered obvious. By focusing on nuclear spin ensembles, we prove
the high-field theorem for a general case of spin-I: grouping of spins in
molecules does not affect the total measurable NMR signal given thermal
equilibrium at high field ($\hbar \gamma B_0 \gg |H_{int}|$, where $|H_{int}|$
is the characteristic amplitude of internal spin-spin interactions). We
demonstrate this first by analyzing equations for spin magnetization and then
for a general case using the density matrix formalism. We exemplify the theorem
implications by predicting NMR signal intensities for ensembles of molecules
containing single, two, and three spins. The theorem is not applied in more
intricate situations, such as zero- to ultralow-field conditions and far from
thermodynamic equilibrium. Considering the populations of rotation levels, the
thermal equilibrium polarization at HF and low temperature for H2 gas
illustrate one of the intricate cases.",2308.15837v1
2023-09-06,Topological spin texture and d-vector rotation in spin-triplet superconductors: A case of UTe2,"A novel spin texture formed by Cooper pair spins is found theoretically with
a phase string attached by half-quantized vortices at both ends in a unit cell
and characterized by its topologically rich vortex structure in a spin-triplet
pairing. It is stable at an intermediate field region sandwiched by two
conventional singular vortex phases below and above it. The d-vector direction
of this spin texture is tilted from the principal crystal axes, whose spin
susceptibility is neither the normal Pauli one \c{hi}N nor zero, describing
microscopically the process of the d-vector rotation phenomena observed
recently in UTe2. We compare the spin texture and singular vortex state in
relation to the quasi-particle structure with Majorana zero modes for STM, the
nuclear spin resonance spectral line width for NMR and {\mu}SR, and the vortex
form factors for SANS to facilitate the identification of the pairing symmetry
in UTe2.",2309.02918v1
2024-02-16,Spin projection noise and the magnetic sensitivity of optically pumped magnetometers,"Present protocols for obtaining the ultimate magnetic sensitivity of
optically pumped magnetometers (OPMs) utilizing alkali-metal ensembles rely on
uncorrelated atoms in stretched states. A new approach for calculating the spin
projection noise (SPN)-limited signal to noise ratio (SNR) and the magnetic
sensitivity of OPMs is proposed. Our model is based solely on the mean-field
density matrix dynamics and in contrast to previous models, it applies to both
low and high field regimes, it takes into account the degree of spin
polarization, the intra- and interhyperfine correlations, the decoherence
processes, the atom-light coupling and the effects of the spin dynamics on the
spin-noise spectra. Fine tuning of the probe frequency allow us to explore
different hyperfine states and ground-state correlations. Especially in the
spin-exchange-relaxation-free (SERF) regime, alongside the magnetic resonance
narrowing and the increased number density, hallmarks of SERF magnetometers, we
report on a new SERF feature; the reduction of spin-projection noise at the
spin precession frequency as a consequence of strongly-correlated hyperfine
spins that attenuate and redistribute SPN when properly probed.",2402.10746v2
2001-03-05,Kondo resonant spectra in coupled quantum dots,"The Kondo effect in coupled quantum dots is investigated from the viewpoint
of transmission spectroscopy using the slave-boson formalism of the Anderson
model. The antiferromagnetic spin-spin coupling $J$ between the dots is taken
into account. Conductance $G$ through the dots connected in a series is
characterized by the competition between the dot-dot tunneling coupling $V_{C}$
and the level broadening $\Delta$ in the dots (dot-lead coupling). When
$V_{C}/\Delta < 1$, the Kondo resonance is formed between each dot and lead,
which is replaced by a spin-singlet state in the dots at low gate voltages. The
gate voltage dependence of $G$ has a sharp peak of $2 e^2/h$ in height in the
crossover region between the Kondo and spin-singlet states. The sharp peak of
$G$ survives when the energy levels are different between the dots. When $V_{C}
/ \Delta > 1$, the ""molecular levels"" between the Kondo resonant states appear;
the Kondo resonant peaks are located below and above the Fermi level in the
leads at low gate voltages. The gate voltage dependence of $G$ has a broad
peak, which is robust against $J$. The broad peak splits into two peaks when
the energy levels are different, reflecting the formation of the asymmetric
molecular levels between the Kondo resonant states.",0103093v1
2016-07-18,Robust Upward Dispersion of the Neutron Spin Resonance in the Heavy Fermion Superconductor Ce$_{1-x}$Yb$_{x}$CoIn$_5$,"The neutron spin resonance is a collective magnetic excitation that appears
in copper oxide, iron pnictide, and heavy fermion unconventional
superconductors. Although the resonance is commonly associated with a
spin-exciton due to the $d$($s^{\pm}$)-wave symmetry of the superconducting
order parameter, it has also been proposed to be a magnon-like excitation
appearing in the superconducting state. Here we use inelastic neutron
scattering to demonstrate that the resonance in the heavy fermion
superconductor Ce$_{1-x}$Yb$_{x}$CoIn$_5$ with $x=0,0.05,0.3$ has a ring-like
upward dispersion that is robust against Yb-doping. By comparing our
experimental data with random phase approximation calculation using the
electronic structure and the momentum dependence of the $d_{x^2-y^2}$-wave
superconducting gap determined from scanning tunneling microscopy for
CeCoIn$_5$, we conclude the robust upward dispersing resonance mode in
Ce$_{1-x}$Yb$_{x}$CoIn$_5$ is inconsistent with the downward dispersion
predicted within the spin-exciton scenario.",1607.05326v1
2016-07-25,Optically Detected Ferromagnetic Resonance in Metallic Ferromagnets via Nitrogen Vacancy Centers in Diamond,"We report quantitative measurements of optically detected ferromagnetic
resonance (ODFMR) of ferromagnetic thin films that use nitrogen-vacancy (NV)
centers in diamonds to transduce FMR into a fluorescence intensity variation.
To uncover the mechanism responsible for these signals, we study ODFMR as we 1)
vary the separation of the NV centers from the ferromagnet (FM), 2) record the
NV center longitudinal relaxation time $T_1$ during FMR, and 3) vary the
material properties of the FM. Based on the results, we propose the following
mechanism for ODFMR. Decay and scattering of the driven, uniform FMR mode
results in spinwaves that produce fluctuating dipolar fields in a spectrum of
frequencies. When the spinwave spectrum overlaps the NV center ground-state
spin resonance frequencies, the dipolar fields from these resonant spinwaves
relax the NV center spins, resulting in an ODFMR signal. These results lay the
foundation for an approach to NV center spin relaxometry to study FM dynamics
without the constraint of directly matching the NV center spin-transition
frequency to the magnetic system of interest, thus enabling an alternate
modality for scanned-probe magnetic microscopy that can sense ferromagnetic
resonance with nanoscale resolution.",1607.07485v1
2016-03-01,Magnetic field dependence of the neutron spin resonance in CeB6,"In zero magnetic field, the famous neutron spin resonance in the f-electron
superconductor CeCoIn5 is similar to the recently discovered exciton peak in
the non-superconducting CeB6. Magnetic field splits the resonance in CeCoIn5
into two components, indicating that it is a doublet. Here we employ inelastic
neutron scattering (INS) to scrutinize the field dependence of spin
fluctuations in CeB6. The exciton shows a markedly different behavior without
any field splitting. Instead, we observe a second field-induced magnon whose
energy increases with field. At the ferromagnetic zone center, however, we find
only a single mode with a non-monotonic field dependence. At low fields, it is
initially suppressed to zero together with the antiferromagnetic order
parameter, but then reappears at higher fields inside the hidden-order phase,
following the energy of an electron spin resonance (ESR). This is a unique
example of a ferromagnetic resonance in a heavy-fermion metal seen by both ESR
and INS consistently over a broad range of magnetic fields.",1603.00383v2
2020-06-23,"Potential model prediction of fully-heavy tetraquarks $QQ\bar{Q}\bar{Q}$ ($Q=c, b$)","The fully-heavy tetraquark states $QQ\bar{Q}\bar{Q}$ ($Q=c, b$) are
systematically investigated by means of a nonrelativistic potential model. The
model is based on the lattice QCD study of the two-body $Q\bar{Q}$ interaction,
which exhibits a spin-independent Cornell potential along with a spin-spin
interaction. The four-body problem is implemented with a highly accurate
computational approach, the Gaussian expansion method. The complex scaling
method is also employed so that the bound, resonance, and scattering states can
be treated on the same footing. Complete set of the four-body configurations,
including meson-meson, diquark-antidiquark, and K-type configurations, as well
as their couplings, are considered for spin-parity quantum numbers
$J^{PC}=0^{++}$, $1^{+-}$, and $2^{++}$ in the $S$-wave channel. No $S$-wave
bound state is found either in the fully-charm tetraquark system or in the
fully-bottom one. However, several narrow resonances, with widths less than 10
MeV in two-meson strong decay, are found in both of these two systems. For the
fully-charm case, the recently reported resonance structures between 6.2 and
7.2 GeV in the di-$J/\psi$ invariant spectrum by the LHCb collaboration, can be
well identified in our calculation. For the fully-bottom case, resonances with
masses between 18.9 and 19.6 GeV are found. The predicted resonances can be
further examined in future experiments.",2006.13756v4
2018-04-09,Discrete resonant Rossby/drift wave triads: an explicit parameterisation and a fast direct numerical search algorithm,"We report results on the explicit parameterisation of discrete Rossby-wave
resonant triads of the Charney-Hasegawa-Mima equation in the small-scale limit
(i.e. large Rossby deformation radius), following up from our previous solution
in terms of elliptic curves (Bustamante and Hayat, 2013). We find an explicit
parameterisation of the discrete resonant wavevectors in terms of two rational
variables. We show that these new variables are restricted to a bounded region
and find this region explicitly. We argue that this can be used to reduce the
complexity of a direct numerical search for discrete triad resonances. Also, we
introduce a new direct numerical method to search for discrete resonances. This
numerical method has complexity ${\mathcal{O}}(N^3)$, where $N$ is the largest
wavenumber in the search. We apply this new method to find all discrete
irreducible resonant triads in the wavevector box of size $5000$, in a
calculation that took about $10.5$ days on a $16$-core machine. Finally, based
on our method of mapping to elliptic curves, we discuss some dynamical
implications regarding the spread of quadratic invariants across scales via
resonant triad interactions, in the form of sharp bounds on the size of the
interacting wavevectors.",1804.03092v1
2021-05-19,Orbital Decay of Short-Period Exoplanets via Tidal Resonance Locking,"A large fraction of known exoplanets have short orbital periods where tidal
excitation of gravity waves within the host star causes the planets' orbits to
decay. We study the effects of tidal resonance locking, in which the planet
locks into resonance with a tidally excited stellar gravity mode. Because a
star's gravity mode frequencies typically increase as the star evolves, the
planet's orbital frequency increases in lockstep, potentially causing much
faster orbital decay than predicted by other tidal theories. Due to nonlinear
mode damping, resonance locking in Sun-like stars likely only operates for
low-mass planets ($M \lesssim 0.1 \, M_{\rm Jup}$), but in stars with
convective cores it can likely operate for all planetary masses. The orbital
decay timescale with resonance locking is typically comparable to the star's
main-sequence lifetime, corresponding to a wide range in effective stellar
quality factor ($10^3 \lesssim Q' \lesssim 10^9$), depending on the planet's
mass and orbital period. We make predictions for several individual systems and
examine the orbital evolution resulting from both resonance locking and
nonlinear wave dissipation. Our models demonstrate how short-period massive
planets can be quickly destroyed by nonlinear mode damping, while short-period
low-mass planets can survive, even though they undergo substantial inward tidal
migration via resonance locking.",2105.09335v2
2022-10-19,Spectral engineering of integrated photonic filters using mode splitting in silicon nanowire integrated standing-wave resonators,"Mode splitting induced by coherent optical mode interference in coupled
resonant cavities is a key phenomenon in photonic resonators that can lead to
powerful and versatile filtering functions, in close analogy to
electromagnetically-induced-transparency, Autler-Townes splitting, Fano
resonances, and dark states. It can not only break the dependence between
quality factor, free spectral range, and physical cavity length, but can also
lead to group delay response and mode interactions that are useful for
enhancing light-material interaction and dispersion engineering in nonlinear
optics. In this work, we investigate mode splitting in standing-wave (SW)
resonators implemented by cascaded Sagnac loop reflectors (CSLRs) and
demonstrate its use for engineering the spectral profile of integrated photonic
filters. By changing the reflectivity of the Sagnac loop reflectors (SLRs) and
the phase shifts along the connecting waveguides, we tailor mode splitting in
the CSLR resonators to achieve a wide range of filter shapes for diverse
applications including enhanced light trapping, flat-top filtering, Q factor
enhancement, and signal reshaping. We present the theoretical designs and
compare the performance of CSLR resonators with three, four, and eight SLRs
fabricated in silicon-on-insulator nanowires. We achieve high performance and
versatile filter shapes via diverse mode splitting that agree well with theory.
The experimental results confirm the effectiveness of our approach towards
realizing integrated multi-functional SW filters for flexible spectral
engineering.",2210.10224v1
2017-08-16,Optical absorption preceding resonant double photoionization of aromatic hydrocarbons hydrocarbons,"We analyze resonances in the double photoionization of a variety of aromatic
hydrocarbons. The resonances reflect the breakup of quasi-bound electron pairs.
The basic premise of this paper is that there is a direct connection between
the quasi-bound pairs and resonant peaks in the optical absorption that are
associated with doubly occupied sites on the perimeter and inside the perimeter
of the molecule. The optical absorption leading to the high-energy resonance
(approximately 40 eV), calculated from a many-site one-dimensional Hubbard
model, has a peak at U, the electrostatic interaction energy for two electrons
with antiparallel spins on the same carbon atom. In the model, there are also
two satellites whose separation from the main resonance is approximately +/-10
eV suggesting that unresolved satellite structure may be contributing to the
linewidth of the resonant peak. The low energy resonances (approximately 10 eV)
involve carbon atoms located inside the perimeter, a configuration present only
in pyrene and coronene (among the hydrocarbons studied). In the case of pyrene,
which has two carbon atoms inside the perimeter, we employ a two-site Hubbard
model to characterize the absorption leading to the quasi-bound state. A brief
analysis of the double photoionization resonance of the heterocyclic inorganic
molecule 1,3,5-triazine presented. We also discuss recent results for the
double photoionization of the cyclic inorganic molecule tribromoborazine and
the organic molecules furan, pyrrole, selenophene, and thiophene where the 2+
ion concentration varies linearly with the difference between the photon energy
and the threshold energy. A theory for the linear behavior is outlined.",1708.05049v1
2023-12-22,Interference of resonances in two-proton emission of $^{16}$Ne,"The $^{16}$Ne nucleus is a two-proton ($2p$) emitter, where an interference
of two resonances is expected since its core-proton subsystem,
$^{15}$F$=^{14}$O$+p$, has separate resonances in the $s_{1/2}$ and $d_{5/2}$
channels. We theoretically investigate the $2p$ emission from the unbound
$0^{+}$ state of $^{16}$Ne. To investigate the $2p$-emitting process, we
perform the time-dependent calculations based on the three-body model of
$^{14}$O$+p+p$. By evaluating the survival probability, a deviation from the
exponential decay is obtained. In correspondence, the $2p$-energy spectrum of
$^{16}$Ne is not of the single resonance, but an interference of the main
narrow and the second broad resonances is obtained. In time-dependent
calculations, the sequential $1p$-$1p$ emission from $^{16}$Ne is relatively
dominant as long as the manifest $s_{1/2}$ resonance in $^{15}$F exists. The
diproton-correlating emission becomes active only if the $s_{1/2}$ resonance is
broad. As conclusion, the $2p$ emission of $^{16}$Ne is one example of the
multi-resonance interference in open-quantum systems. The $s_{1/2}$
intermediate resonance is essential to realize this interference, and induces
the sequential emission. The $2p$-decaying state is predicted to have the
spin-singlet entanglement independently of whether the emission is sequential
or correlating.",2312.15017v2
2011-02-09,Observation of second-harmonic generation induced by pure spin currents,"Extensive efforts are currently being devoted to developing a new electronic
technology, called spintronics, where the spin of electrons is explored to
carry information. [1,2] Several techniques have been developed to generate
pure spin currents in many materials and structures. [3-10] However, there is
still no method available that can be used to directly detect pure spin
currents, which carry no net charge current and no net magnetization.
Currently, studies of pure spin currents rely on measuring the induced spin
accumulation with optical techniques [5, 11-13] or spin-valve configurations.
[14-17] However, the spin accumulation does not directly reflect the spatial
distribution or temporal dynamics of the pure spin current, and therefore
cannot monitor the pure spin current in a real-time and real-space fashion.
This imposes severe constraints on research in this field. Here we demonstrate
a second-order nonlinear optical effect of the pure spin current. We show that
such a nonlinear optical effect, which has never been explored before, can be
used for the non-invasive, non-destructive, and real-time imaging of pure spin
currents. Since this detection scheme does not rely on optical resonances, it
can be generally applied in a wide range of materials with different electronic
bandstructures. Furthermore, the control of nonlinear optical properties of
materials with pure spin currents may have potential applications in photonics
integrated with spintronics.",1102.1784v1
2013-05-01,Ballistic spin transport in exciton gases,"Traditional spintronics relies on spin transport by charge carriers, such as
electrons in semiconductor crystals. This brings several complications: the
Pauli principle prevents the carriers from moving with the same speed; Coulomb
repulsion leads to rapid dephasing of electron flows. Spin-optronics is a
valuable alternative to traditional spintronics. In spin-optronic devices the
spin currents are carried by electrically neutral bosonic quasi-particles:
excitons or exciton-polaritons. They can form highly coherent quantum liquids
and carry spins over macroscopic distances. The price to pay is a finite
life-time of the bosonic spin carriers. We present the theory of exciton
ballistic spin transport which may be applied to a range of systems where
bosonic spin transport has been reported, in particular, to indirect excitons
in coupled GaAs/AlGaAs quantum wells. We describe the effect of spin-orbit
interaction of electrons and holes on the exciton spin, account for the Zeeman
effect induced by external magnetic fields, long range and short range exchange
splittings of the exciton resonances. We also consider exciton transport in the
non-linear regime and discuss the definitions of exciton spin current,
polarization current and spin conductivity.",1305.0133v3
2013-05-10,Polytype control of spin qubits in silicon carbide,"Crystal defects can confine isolated electronic spins and are promising
candidates for solid-state quantum information. Alongside research focusing on
nitrogen vacancy centers in diamond, an alternative strategy seeks to identify
new spin systems with an expanded set of technological capabilities, a
materials driven approach that could ultimately lead to ""designer"" spins with
tailored properties. Here, we show that the 4H, 6H and 3C polytypes of SiC all
host coherent and optically addressable defect spin states, including spins in
all three with room-temperature quantum coherence. The prevalence of this spin
coherence shows that crystal polymorphism can be a degree of freedom for
engineering spin qubits. Long spin coherence times allow us to use double
electron-electron resonance to measure magnetic dipole interactions between
spin ensembles in inequivalent lattice sites of the same crystal. Together with
the distinct optical and spin transition energies of such inequivalent spins,
these interactions provide a route to dipole-coupled networks of separately
addressable spins.",1305.2445v1
2018-05-07,Electrically controlled long-distance spin transport through an antiferromagnetic insulator,"Spintronics uses spins, the intrinsic angular momentum of electrons, as an
alternative for the electron charge. Its long-term goal is in the development
of beyond-Moore low dissipation technology devices. Recent progress
demonstrated the long-distance transport of spin signals across ferromagnetic
insulators. Antiferromagnetically ordered materials are however the most common
class of magnetic materials with several crucial advantages over ferromagnetic
systems. In contrast to the latter, antiferromagnets exhibit no net magnetic
moment, which renders them stable and impervious to external fields. In
addition, they can be operated at THz frequencies. While fundamentally their
properties bode well for spin transport, previous indirect observations
indicate that spin transmission through antiferromagnets is limited to short
distances of a few nanometers. Here we demonstrate the long-distance, over tens
of micrometers, propagation of spin currents through hematite (\alpha-Fe2O3),
the most common antiferromagnetic iron oxide, exploiting the spin Hall effect
for spin injection. We control the spin current flow by the interfacial
spin-bias and by tuning the antiferromagnetic resonance frequency with an
external magnetic field. This simple antiferromagnetic insulator is shown to
convey spin information parallel to the compensated moment (N\'eel order) over
distances exceeding tens of micrometers. This newly-discovered mechanism
transports spin as efficiently as the net magnetic moments in the best-suited
complex ferromagnets. Our results pave the way to ultra-fast, low-power
antiferromagnet-insulator-based spin-logic devices that operate at room
temperature and in the absence of magnetic fields.",1805.02451v1
2019-02-01,Photoinduced Rashba spin to charge conversion via interfacial unoccupied state,"At interfaces with inversion symmetry breaking, Rashba effect couples the
motion of electrons to their spin; as a result, spin-charge interconversion
mechanism can occur. These interconversion mechanisms commonly exploit Rashba
spin splitting at the Fermi level by spin pumping or spin torque ferromagnetic
resonance. Here, we report evidence of significant photoinduced spin to charge
conversion via Rashba spin splitting in an unoccupied state above the Fermi
level at the Cu(111)/$\alpha$-Bi$_{2}$O$_{3}$ interface. We predict an average
Rashba coefficient of $1.72\times 10^{-10}eV.m$ at 1.98 eV above the Fermi
level, by fully relativistic first-principles analysis of the interfacial
electronic structure with spin orbit interaction. We find agreement with our
observation of helicity dependent photoinduced spin to charge conversion
excited at 1.96 eV at room temperature, with spin current generation of
$J_{s}=10^{6}A/m^{2}$. The present letter shows evidence of efficient
spin-charge conversion exploiting Rashba spin splitting at excited states,
harvesting light energy without magnetic materials or external magnetic fields.",1902.00237v2
2017-10-04,Possible evidence for spin-transfer torque induced by spin-triplet supercurrent,"Cooper pairs in superconductors are normally spin singlet. Nevertheless,
recent studies suggest that spin-triplet Cooper pairs can be created at
carefully engineered superconductor-ferromagnet interfaces. If Cooper pairs are
spin-polarized they would transport not only charge but also a net spin
component, but without dissipation, and therefore minimize the heating effects
associated with spintronic devices. Although it is now established that triplet
supercurrents exist, their most interesting property - spin - is only inferred
indirectly from transport measurements. In conventional spintronics, it is well
known that spin currents generate spin-transfer torques that alter
magnetization dynamics and switch magnetic moments. The observation of similar
effects due to spin-triplet supercurrents would not only confirm the net spin
of triplet pairs but also pave the way for applications of superconducting
spintronics. Here, we present a possible evidence for spin-transfer torques
induced by triplet supercurrents in superconductor/ferromagnet/superconductor
(S/F/S) Josephson junctions. Below the superconducting transition temperature
T_c, the ferromagnetic resonance (FMR) field at X-band (~ 9.0 GHz) shifts
rapidly to a lower field with decreasing temperature due to the spin-transfer
torques induced by triplet supercurrents. In contrast, this phenomenon is
absent in ferromagnet/superconductor (F/S) bilayers and
superconductor/insulator/ferromagnet/superconductor (S/I/F/S) multilayers where
no supercurrents pass through the ferromagnetic layer. These experimental
observations are discussed with theoretical predictions for ferromagnetic
Josephson junctions with precessing magnetization.",1710.01534v1
2021-03-16,Large Spin-to-Charge Conversion in Ultrathin Gold-Silicon Multilayers,"Investigation of the spin Hall effect in gold has triggered increasing
interest over the past decade, since gold combines the properties of a large
bulk spin diffusion length and strong interfacial spin-orbit coupling. However,
discrepancies between the values of the spin Hall angle of gold reported in the
literature have brought into question the microscopic origin of the spin Hall
effect in Au. Here, we investigate the thickness dependence of the spin-charge
conversion efficiency in single Au films and ultrathin Au/Si multilayers by
non-local transport and spin-torque ferromagnetic resonance measurements. We
show that the spin-charge conversion efficiency is strongly enhanced in
ultrathin Au/Si multilayers, reaching exceedingly large values of 0.99 +/- 0.34
when the thickness of the individual Au layers is scaled down to 2 nm. These
findings reveal the coexistence of a strong interfacial spin-orbit coupling
effect which becomes dominant in ultrathin Au, and bulk spin Hall effect with a
relatively low bulk spin Hall angle of 0.012 +/- 0.005. Our experimental
results suggest the key role of the Rashba-Edelstein effect in the
spin-to-charge conversion in ultrathin Au.",2103.08876v1
2022-01-12,Light and microwave driven spin pumping across FeGaB-BiSb interface,"3-D topological insulators (TI) with large spin Hall conductivity have
emerged as potential candidates for spintronic applications. Here, we report
spin to charge conversion in bilayers of amorphous ferromagnet (FM)
Fe_{78}Ga_{13}B_{9} (FeGaB) and 3-D TI Bi_{85}Sb_{15} (BiSb) activated by two
complementary techniques: spin pumping and ultrafast spin-current injection. DC
magnetization measurements establish the soft magnetic character of FeGaB
films, which remains unaltered in the heterostructures of FeGaB-BiSb. Broadband
ferromagnetic resonance (FMR) studies reveal enhanced damping of precessing
magnetization and large value of spin mixing conductance (5.03 x 10^{19}
m^{-2}) as the spin angular momentum leaks into the TI layer. Magnetic field
controlled bipolar dc voltage generated across the TI layer by inverse spin
Hall effect is analyzed to extract the values of spin Hall angle and spin
diffusion length of BiSb. The spin pumping parameters derived from the
measurements of the femtosecond light-pulse-induced terahertz emission are
consistent with the result of FMR. Kubo-Bastin formula and tight-binding model
calculations shed light on the thickness-dependent spin-Hall conductivity of
the TI films, with predictions that are in remarkable agreement with the
experimental data. Our results suggest that room temperature deposited
amorphous and polycrystalline heterostructures provide a promising platform for
creating novel spin orbit torque devices.",2201.04686v1
2022-01-31,Tuning spin-orbit torques across the phase transition in VO$_2$/NiFe heterostructure,"The emergence of spin-orbit torques as a promising approach to
energy-efficient magnetic switching has generated large interest in material
systems with easily and fully tunable spin-orbit torques. Here, current-induced
spin-orbit torques in VO$_2$/NiFe heterostructures were investigated using
spin-torque ferromagnetic resonance, where the VO$_2$ layer undergoes a
prominent insulator-metal transition. A roughly two-fold increase in the
Gilbert damping parameter, $\alpha$, with temperature was attributed to the
change in the VO$_2$/NiFe interface spin absorption across the VO$_2$ phase
transition. More remarkably, a large modulation ($\pm$100%) and a sign change
of the current-induced spin-orbit torque across the VO$_2$ phase transition
suggest two competing spin-orbit torque generating mechanisms. The bulk spin
Hall effect in metallic VO$_2$, corroborated by our first-principles
calculation of spin Hall conductivity, $\sigma_{SH} \approx 10^4
\frac{\hbar}{e} \Omega^{-1} m^{-1}$, is verified as the main source of the
spin-orbit torque in the metallic phase. The self-induced/anomalous torque in
NiFe, of the opposite sign and a similar magnitude to the bulk spin Hall effect
in metallic VO$_2$, could be the other competing mechanism that dominates as
temperature decreases. For applications, the strong tunability of the torque
strength and direction opens a new route to tailor spin-orbit torques of
materials which undergo phase transitions for new device functionalities.",2201.12984v1
2024-04-04,Waveguide QED at the onset of spin-spin correlations,"We experimentally explore the competition between light-mediated and direct
matter-matter interactions in waveguide quantum electrodynamics. For this, we
couple a superconducting line to a model magnetic material, made of organic
free radical DPPH molecules with a spin $S=1/2$ and a $g_{S}$ factor very close
to that of a free electron. The microwave transmission has been measured in a
wide range of temperatures ($0.013$ K $\leq T \leq 2$ K), magnetic fields
($0\leq B \leq 0.5$ T) and frequencies ($0 \leq \omega/2 \pi \leq 14$ GHz). We
find that molecules belonging to the crystal sublattice B form one-dimensional
spin chains. Temperature then controls intrinsic spin correlations along the
chain in a continuous and monotonic way. In the paramagnetic region ($T > 0.7$
K), the microwave transmission shows evidences for the collective coupling of
quasi-identical spins to the propagating photons, with coupling strengths that
reach values close to the dissipation rates. As $T$ decreases, the growth of
intrinsic spin correlations, combined with the anisotropy in the spin-spin
exchange constants, break down the collective spin-photon coupling. In this
regime, the temperature dependence of the spin resonance visibility reflects
the change in the nature of the dominant spin excitations, from single spin
flips to bosonic magnons, which is brought about by the magnetic correlation
growth.",2404.03727v1
2009-03-26,Emergence of the persistent spin helix in semiconductor quantum wells,"According to Noethers theorem, for every symmetry in nature there is a
corresponding conservation law. For example, invariance with respect to spatial
translation corresponds to conservation of momentum. In another well-known
example, invariance with respect to rotation of the electrons spin, or SU(2)
symmetry, leads to conservation of spin polarization. For electrons in a solid,
this symmetry is ordinarily broken by spin-orbit coupling, allowing spin
angular momentum to flow to orbital angular momentum. However, it has recently
been predicted that SU(2) can be achieved in a two-dimensional electron gas,
despite the presence of spin-orbit coupling. The corresponding conserved
quantities include the amplitude and phase of a helical spin density wave
termed the persistent spin helix. SU(2) is realized, in principle, when the
strength of two dominant spin-orbit interactions, the Rashba (strength
parameterized by \alpha) and linear Dresselhaus (\beta_1), are equal. This
symmetry is predicted to be robust against all forms of spin-independent
scattering, including electron-electron interactions, but is broken by the
cubic Dresselhaus term (\beta_3) and spin-dependent scattering. When these
terms are negligible, the distance over which spin information can propagate is
predicted to diverge as \alpha approaches \beta_1. Here we observe
experimentally the emergence of the persistent spin helix in GaAs quantum wells
by independently tuning \alpha and \beta_1. Using transient spin-grating
spectroscopy, we find a spin-lifetime enhancement of two orders of magnitude
near the symmetry point.........",0903.4709v2
2014-08-20,Coherent transport and manipulation of spins in indirect exciton nanostructures,"We report on the coherent control and transport of indirect exciton (IX)
spins in GaAs double quantum well (DQW) nanostructures. The spin dynamics was
investigated by optically generating spins using a focused, circularly
polarized light spot and by probing their spatial distribution using spatially
and polarization resolved photoluminescence spectroscopy. Optically injected
exciton spins precess while diffusing over distances exceeding 20 {\mu}m from
the excitation spot with a spatial precession frequency that depends on the
spin transport direction as well as on the bias applied across the DQW
structure. This behavior is attributed to the spin precession in the effective
magnetic field induced by the spin-orbit interaction. From the dependence of
the spin dynamics on the transport direction, bias and external magnetic fields
we directly determined the Dresselhaus and Rashba spin splitting coefficients
for the structure. The precession dynamics is essentially independent on the IX
density, thus indicating that the long spin lifetimes are not associated with
IX collective effects. The latter, together with the negligible contribution of
holes to the spin dynamics, are rather attributed to spatial separation of the
electron and hole wave functions by the electric field, which reduces the
electron-hole exchange interaction. Coherent spin precession over long
transport distances as well as the control of the spin vector using electric
and magnetic fields open the way for the application of IX spins in the quantum
information processing.",1408.4547v1
2002-04-18,"Ballistic spin transport through electronic stub tuners: spin precession, selection, and square-wave transmission","Ballistic spin transport is studied through electronic tuners with double
stubs attached to them. The spins precess due to the spin-orbit interaction.
Injected polarized spins can exit the structure polarized in the opposite
direction. A nearly square-wave spin transmission, with values 1 and 0, can be
obtained using a periodic system of symmetric stubs and changing their length
or width. The gaps in the transmission can be widened using asymmetric stubs.
An additional modulation is obtained upon combining stub structures with
different values of the spin-orbit strength.",0204391v1
1992-11-19,Spin effects in the inspiral of coalescing compact binaries,"We derive the contributions of spin-orbit and spin-spin coupling to the
gravitational radiation from coalescing binary systems of spinning compact
objects. We calculate spin effects in the symmetric, trace-free radiative
multipoles that determine the gravitational waveform, and the rate of energy
loss. Assuming a balance between energy radiated and orbital energy lost, we
determine the spin effects in the evolution of the orbital frequency and
orbital radius. Assuming that a laser interferometric gravitational observatory
can track the gravitational-wave frequency (twice the orbital frequency) as it
sweeps through its sensitive bandwidth between about 10 Hz and one kHz, we
estimate the accuracy with which the spins of the component bodies can be
determined from the gravitational-wave signal.",9211025v1
2007-08-29,Spin-charge separation in a strongly correlated spin-polarized chain,"We combine the first-quantized path-integral formalism and bosonization to
develop a phenomenological theory for spin-charge coupled dynamics in
one-dimensional (1D) ferromagnetic systems with strong interparticle repulsion,
at low temperatures. We assume an effective spin-charge separation and retain
the standard Luttinger-liquid plasmon branch, which is explicitly coupled to a
ferromagnetic spin-wave texture with a quadratic dispersion. The dynamic spin
structure severely suppresses the plasmon peak in the single-particle
propagator, in both fermionic and bosonic systems. Our analysis provides an
effective theory for the new universality class of 1D ferromagnetic systems,
capturing both the trapped spin and propagating spin-wave regimes of the
long-time behavior.",0708.4012v4
2008-11-14,Hall Effect of Spin Waves in Frustrated Magnets,"We examine a possible spin Hall effect for localized spin systems with no
charge degrees of freedom. In this scenario, a longitudinal magnetic field
gradient induces a transverse spin current carried by spin wave excitations
with an anomalous velocity which is associated with the Berry curvature raised
by spin chirality, in analogy with anomalous Hall effects in itinerant electron
systems. Our argument is based on a semiclassical equations of motion
applicable to general spin systems. Also, a microscopic model of frustrated
magnets which exhibits the anamalous spin Hall effect is presented.",0811.2263v6
2009-09-14,Collective modes of a helical liquid,"We study low energy collective modes and transport properties of the ""helical
metal"" on the surface of a topological insulator. At low energies, electrical
transport and spin dynamics at the surface are exactly related by an operator
identity equating the electric current to the in-plane components of the spin
degrees of freedom. From this relation it follows that an undamped spin wave
always accompanies the sound mode in the helical metal -- thus it is possible
to `hear' the sound of spins. In the presence of long range Coulomb
interactions, the surface plasmon mode is also coupled to the spin wave, giving
rise to a hybridized ""spin-plasmon"" mode. We make quantitative predictions for
the spin-plasmon in ${\rm Bi}_2{\rm Se}_3$, and discuss its detection in a
spin-grating experiment.",0909.2477v2
2010-07-08,Spin induced multipole moments for the gravitational wave flux from binary inspirals to third Post-Newtonian order,"Using effective field theory techniques we calculate the source multipole
moments needed to obtain the spin contributions to the power radiated in
gravitational waves from inspiralling compact binaries to third Post-Newtonian
order (3PN). The multipoles depend linearly and quadratically on the spins and
include both spin(1)spin(2) and spin(1)spin(1) components. The results in this
paper provide the last missing ingredient required to determine the phase
evolution to 3PN including all spin effects which we will report in a separate
paper.",1007.1312v2
2011-08-14,Observation of non-conventional spin waves in composite fermion ferromagnets,"We find unexpected low energy excitations of fully spin-polarized
composite-fermion ferromagnets in the fractional quantum Hall liquid, resulting
from a complex interplay between a topological order manifesting through new
energy levels and a magnetic order due to spin polarization. The lowest energy
modes, which involve spin reversal, are remarkable in displaying unconventional
negative dispersion at small momenta followed by a deep roton minimum at larger
momenta. This behavior results from a nontrivial mixing of spin-wave and
spin-flip modes creating a spin-flip excitonic state of composite-fermion
particle-hole pairs. The striking properties of spin-flip excitons imply highly
tunable mode couplings that enable fine control of topological states of
itinerant two-dimensional ferromagnets.",1108.2901v1
2012-04-15,Classical Aspects of Higher Spin Topologically Massive Gravity,"We study the classical solutions of three dimensional topologically massive
gravity (TMG) and its higher spin generalization, in the first order
formulation. The action of higher spin TMG has been proposed in arXiv:1110.5113
to be of a Chern-Simons-like form. The equations of motion are more complicated
than the ones in pure higher spin AdS$_3$ gravity, but are still tractable. As
all the solutions in higher spin gravity are automatically the solutions of
higher spin TMG, we focus on other solutions. We manage to find the AdS pp-wave
solutions with higher spin hair, and find that the nonvanishing higher spin
fields may or may not modify the pp-wave geometry. In order to discuss the
warped spacetime, we introduce the notion of special Killing vector, which is
defined to be the symmetry on the frame-like fields. We reproduce various
warped spacetimes of TMG in our framework, with the help of special Killing
vectors.",1204.3282v2
2012-08-20,Reversal and Termination of Current-Induced Domain Wall Motion via Magnonic Spin-Transfer Torque,"We investigate the domain wall dynamics of a ferromagnetic wire under the
combined influence of a spin-polarized current and magnonic spin-transfer
torque generated by an external field, taking also into account Rashba
spin-orbit coupling interactions. It is demonstrated that current-induced
motion of the domain wall may be completely reversed in an oscillatory fashion
by applying a magnonic spin-transfer torque as long as the spin-wave velocity
is sufficiently high. Moreover, we show that the motion of the domain wall may
be fully terminated by means of the generation of spin-waves, suggesting the
possibility to pin the domain-walls to predetermined locations. We also discuss
how strong spin-orbit interactions modify these results.",1208.4108v1
2013-07-19,Waves in the unseen : theory of spin excitations in a quantum spin nematic,"The idea that a quantum magnet could act like a liquid crystal, breaking
spin-rotation symmetry without breaking time-reversal symmetry, holds an
abiding fascination. However, the very fact that spin nematic states do not
break time-reversal symmetry renders them ""invisible"" to the most common probes
of magnetism - they do not exhibit magnetic Bragg peaks, a static splitting of
lines in NMR spectra, or oscillations in muSR. Nonetheless, as a consequence of
breaking spin-rotation symmetry, spin-nematic states do possess a
characteristic spectrum of dispersing excitations which could be observed in
experiment. With this in mind, we develop a symmetry-based description of
long-wavelength excitations in a spin-nematic state, based on an SU(3)
generalisation of the quantum non-linear sigma model. We use this field theory
to make explicit predictions for inelastic neutron scattering, and argue that
the wave-like excitations it predicts could be used to identify the symmetries
broken by the otherwise unseen spin-nematic order.",1307.5131v2
2013-08-16,Quantum kinetics of spinning neutral particles: General theory and Spin wave dispersion,"Plasma physics give an example of physical system of particles with the long
range interaction. At small velocity of particles we can consider the plasma
approximately as a system of particles with the Coulomb interaction. The
Coulomb interaction is isotropic. Systems of spinning neutral particles have
long-range anisotropic interparticle interaction. So, they can reveal more
reach properties than plasma. Furthermore for studying of systems of spinning
particles we can develop kinetic and hydrodynamic methods analogous to used for
the plasma. We derive kinetic equations by a new method, which is the
generalization of the many-particle quantum hydrodynamics. Obtained set of
kinetic equations is truncated, so we have closed set of two equations. One of
them is the kinetic equation for quantum distribution function. The second
equation is the equation for the spin-distribution. Which describes the spin
kinetic evolution and gives contribution in time evolution of the distribution
function. Our method allows to obtain equations as for three dimensional system
of particles and for low dimensional systems. So, we consider spin waves in
three- and two dimensional systems of neutral spinning particles.",1308.3715v1
2014-02-17,Incommensurate spin density wave as a signature of spin-orbit coupling,"Close to half filling and in the limit of strong interactions the Hubbard
model leads a spin Hamiltonian. In its original isotropic form this is the
Heisenberg model with antiferromagnetic coupling $J$. On a square lattice there
is no frustration and the ground state is a classical antiferromagnet denoted
by the commensurate order vector ${\bf Q}=(\pi,\pi)$. In this work we show that
the inclusion of spin orbit coupling (SOC) in the fermionic Hubbard model on a
square lattice leads to an incommensurate spin density wave (ISDW) in the
strong interactions limit at half filling. In this limit the Hubbard model
leads to a non-diagonal and anisotropic spin Hamiltonian which exhibits the
incommensurate spin order as its classical ground state. We note that an ISDW
can be found in systems regardless of spin orbit-coupling due to nesting and
lattice distortion. These effects, however, can usually be recognized by
experimental probes.",1402.4093v1
2014-11-30,Quantum Theory of Helimagnetic Thin Films,"We study properties of a helimagnetic thin film with quantum Heisenberg spin
model by using the Green's function method. Surface spin configuration is
calculated by minimizing the spin interaction energy. It is shown that the
angles between spins near the surface are strongly modified with respect to the
bulk configuration. Taking into account this surface spin reconstruction, we
calculate self-consistently the spin-wave spectrum and the layer magnetizations
as functions of temperature up to the disordered phase. The spin-wave spectrum
shows the existence of a surface-localized branch which causes a low surface
magnetization. We show that quantum fluctuations give rise to a crossover
between the surface magnetization and interior-layer magnetizations at low
temperatures. We calculate the transition temperature and show that it depends
strongly on the helical angle. Results are in agreement with existing
experimental observations on the stability of helical structure in thin films
and on the insensitivity of the transition temperature with the film thickness.
We also study effects of various parameters such as surface exchange and
anisotropy interactions. Monte Carlo simulations for the classical spin model
are also carried out for comparison with the quantum theoretical result.",1412.0184v1
2015-09-11,Non-perturbative Correlation Effects in Diluted Magnetic Semiconductors,"The effects of carrier-impurity correlations due to a Kondo-like spin-spin
interaction in diluted magnetic semiconductors are investigated. These
correlations are not only responsible for a transfer of spins between the
carriers and the impurities, but also produce non-perturbative effects in the
spin dynamics such as renormalization of the precession frequency of the
carrier spins, which can reach values of several percent in CdMnTe quantum
wells. In two-dimensional systems, the precession frequency renormalization for
a single electron spin with defined wave vector shows logarithmic divergences
similar to those also known from the Kondo problem in metals. For smooth
electron distributions, however, the divergences disappear due to the
integrability of the logarithm. A possible dephasing mechanism caused by the
wave-vector dependence of the electron spin precession frequencies is found to
be of minor importance compared to the spin transfer from the carrier to the
impurity system. In the Markov limit of the theory, a quasi-equilibrium
expression for the carrier-impurity correlation energy can be deduced
indicating the formation of strongly correlated carrier-impurity states for
temperatures in the mK range.",1509.03442v1
2017-02-22,Is spin superfluidity possible in YIG films?,"Recently it was suggested that stationary spin supercurrents (spin
superfluidity) are possible in the magnon condensate observed in
yttrium-iron-garnet (YIG) magnetic films under strong external pumping. Here we
analyze this suggestion. From topology of the equilibrium order parameter in
YIG one must not expect energetic barriers making spin supercurrents
metastable. However some small barriers of dynamical origin are possible
nevertheless. The critical phase gradient (analog of the Landau critical
velocity in superfluids) is proportional to intensity of the coherent spin wave
(number of condensed magnons). The conclusion is that although spin
superfluidity in YIG films is possible in principle, the published claim of its
observation is not justified.
  The analysis revealed that the widely accepted spin-wave spectrum in YIG
films with magnetostatic and exchange interaction required revision. This led
to revision of non-linear corrections, which determine stability of the magnon
condensate with and without spin supercurrents.",1702.06994v2
2021-04-30,Unstable binary black-hole spins: post-Newtonian theory and numerical relativity,"Spin precession occurs in binary black holes whose spins are misaligned with
the orbital angular momentum. Otherwise, the spin configuration is constant and
the subsequent binary dynamics and gravitational-wave emission are much
simpler. We summarize a series of works which has shown that, while three of
the aligned configurations are stable equilibria, the `up-down' configuration,
in which the heavier (lighter) black hole is (anti) aligned with the orbital
angular momentum, is unstable when perturbed; at a critical point in the
inspiral the black hole spins begin to tilt wildly as precession takes over. We
present two equivalent approaches to derive the instability onset based on
multitimescale post-Newtonian techniques, and point out that the instability
has a predictable endpoint. Finally, we demonstrate the presence of this
precessional instability in the strong-field regime of numerical relativity
with simulations of aligned-spin binaries lasting $\sim100$ orbits before
merger. The spins of up-down systems can tilt by $\sim90^\circ$, leaving a
notable imprint in the emitted gravitational-wave signals and providing a
possible mechanism to form precessing systems in astrophysical environments
from which sources are preferentially born with (anti) aligned spins.",2104.15011v1
2021-10-24,Spin dynamics in the skyrmion-host lacunar spinel GaV4S8,"In the lacunar spinel GaV4S8, the interplay of spin, charge, and orbital
degrees of freedom produces a rich phase diagram that includes an unusual
Neel-type skyrmion phase composed of molecular spins. To provide insight into
the interactions underlying this complex phase diagram, we study the spin
excitations in GaV4S8 through inelastic neutron scattering measurements on
polycrystalline and single-crystal samples. Using linear spin-wave theory, we
describe the spin-wave excitations using a model where V4 clusters decorate an
FCC lattice. The effective cluster model includes a ferromagnetic interaction
and a weaker antisymmetric Dzyaloshinskii-Moriya (DM) interaction between the
neighboring molecular spins. Our work clarifies the spin interactions in GaV4S8
and supports the picture of interacting molecular clusters.",2110.12322v2
2020-01-18,Giant photonic spin Hall effect near the Dirac points,"The origin of spin-orbit interaction of light at a conventional optical
interface lies in the transverse nature of the photon polarization: The
polarizations associated with the plane-wave components experience slightly
different rotations in order to satisfy the transversality after reflection or
refraction. Recent advances in topological photonic materials provide crucial
opportunities to reexamine the spin-orbit interaction of light at the unique
optical interface. Here, we establish a general model to describe the
spin-orbit interaction of light in the photonic Dirac metacrystal. We find a
giant photonic spin Hall effect near the Dirac points when a Gaussian beam
impinges at the interface of the photonic Dirac metacrystal. The giant photonic
spin Hall effect is attribute to the strong spin-orbit interaction of light,
which manifests itself as the large polarization rotations of different
plane-wave components. We believe that these results may provide insight into
the fundamental properties of the spin-orbit interaction of light in the
topological photonic systems.",2001.06609v1
2020-07-07,Unidirectional spin transport of a spin-orbit-coupled atomic matter wave using a moving Dirac $δ$-potential well,"We study the transport of a spin-orbit-coupled atomic matter wave using a
moving Dirac $\delta$-potential well. In a spin-orbit-coupled system, bound
states can be formed in both ground and excited energy levels with a Dirac
$\delta$ potential. Because Galilean invariance is broken in a
spin-orbit-coupled system, moving of the potential will induce a
velocity-dependent effective detuning. This induced detuning breaks the spin
symmetry and makes the ground-state transporting channel be spin-$\uparrow$
($\downarrow$) favored while makes the excited-state transporting channel be
spin-$\downarrow$ ($\uparrow$) favored for a positive-direction
(negative-direction) transporting. When the $\delta$-potential well moves at a
small velocity, both the ground-state and the excited-state channels contribute
to the transportation, and thus both the spin components can be efficiently
transported. However, when the moving velocity of the $\delta$-potential well
exceeds a critical value, the induced detuning is large enough to eliminate the
excited bound state, and makes the ground bound state the only transporting
channel, in which only the spin-$\uparrow$ ($\downarrow$) component can be
efficiently transported in a positive (negative) direction. This work
demonstrates a prototype of unidirectional spin transport.",2007.03147v1
1997-11-25,Nonlinear Spin Dynamics in Nuclear Magnets,"A method is developed for solving nonlinear systems of differential, or
integrodifferential, equations with stochastic fields. The method makes it
possible to give an accurate solution for an interesting physical problem: What
are the peculiarities of nonlinear spin dynamics in nonequilibrium nuclear
magnets coupled with a resonator? Evolution equations for nuclear spins are
derived basing on a Hamiltonian with dipole interactions. The ensemble of spins
is coupled with a resonator electric circuit. Seven types of main relaxation
regimes are found: free induction, collective induction, free relaxation,
collective relaxation, weak superradiance, pure superradiance, and triggered
superradiance. The initial motion of spins can be originated by two reasons,
either by an imposed initial coherence or by local spin fluctuations due to
nonsecular dipole interactions. The relaxation regimes caused by the second
reason cannot be described by the Bloch equations. Numerical estimates show
good agreement with experiment.",9711259v1
1999-01-28,From Magnons to the Resonance Peak: Spin Dynamics in High-T_C Superconducting Cuprates by Inelastic Neutron Scattering,"The spin dynamics of high temperature superconductors measured by inelastic
neutron scattering is reviewed. The spin susceptibility evolves a lot with
increasing doping from the undoped insulating state to the overdoped metallic
state. In the superconducting state, a strong magnetic resonance peak occurs in
the spin excitation spectrum whose energy is proportional to the
superconducting temperature. In underdoped and optimally doped regimes, normal
state antiferromagnetic fluctuations are observed, proving the existence of
strong electronic correlations in cuprates. They are characterized by a spin
pseudo-gap. In contrast, these dynamical spin correlations vanish in overdoped
samples.",9901333v2
2000-09-25,An Electron Spin Resonance Selection Rule for Spin-Gapped Systems,"The direct electron spin resonance (ESR) absorption between a singlet ground
state and the triplet excited states of spin gap systems is investigated. Such
an absorption, which is forbidden by the conservation of the total spin quantum
number in isotropic Hamiltonians, is allowed by the Dzyaloshinskii-Moriya
interaction. We show a selection rule in the presence of this interaction,
using the exact numerical diagonalization of the finite cluster of the
quasi-one-dimensional bond-alternating spin system. The selection rule is also
modified into a suitable form in order to interpret recent experimental results
on CuGeO$_3$ and NaV$_2$O$_5$.",0009385v1
2003-05-16,Spin-orbit coupling and electron spin resonance for interacting electrons in carbon nanotubes,"We review the theoretical description of spin-orbit scattering and electron
spin resonance in carbon nanotubes. Particular emphasis is laid on the effects
of electron-electron interactions. The spin-orbit coupling is derived, and the
resulting ESR spectrum is analyzed both using the effective low-energy field
theory and numerical studies of finite-size Hubbard chains and two-leg Hubbard
ladders. For single-wall tubes, the field theoretical description predicts a
double peak spectrum linked to the existence of spin-charge separation. The
numerical analysis basically confirms this picture, but also predicts
additional features in finite-size samples.",0305388v2
2003-10-14,Spin resonance peak in Na$_{x}$CoO$_{2}\cdot y$H$_{2}$O superconductors: A probe of the pairing symmetry,"Motivated by the recent discovery of superconductivity in layered
Na$_{x}$CoO$_{2}\cdot y$H$_{2}$O compound, we investigate theoretically the
spin dynamics in the superconducting state with three possible $p_{x}+ip_{y}$-,
$d+id'$-, and $f$-wave pairing symmetries in two-dimensional triangular
lattices. We find that a spin resonance peak, which is elaborated to have a
close relevance to the relative phase of the gap function and the geometry of
the Fermi surface, appears in both in-plane and out-of-plane components of the
spin susceptibility $\chi$ for the spin-singlet $d+id'$-wave pairing, while
only in the out-of-plane(in-plane) component of $\chi$ for the spin-triplet
$p_{x}+ip_{y}$-wave ($f$-wave) pairing. Because the pairing symmetry in this
compound is still hotly debated at present, this distinct feature may be used
to probe or determine it unambiguously with future neutron scattering
experiments.",0310308v1
2005-09-19,Enhancement of Spin Coherence using Q-factor Engineering in Semiconductor Microdisk Lasers,"Semiconductor microcavities offer unique means of controlling light-matter
interactions, which have led to the development of a wide range of applications
in optical communications and inspired proposals for quantum information
processing and computational schemes. Studies of spin dynamics in microcavities
- a new and promising research field - have revealed novel effects such as
polarization beats, stimulated spin scattering, and giant Faraday rotation.
Here, we study the electron spin dynamics in optically-pumped GaAs microdisk
lasers with quantum wells (QWs) and interface-fluctuation quantum dots (QDs) in
the active region. In particular, we address the question of how the electron
spin dynamics are modified by the stimulated emission in the disks, and observe
an enhancement of the spin lifetime when the optical excitation is in resonance
with a high quality (Q ~ 5000) lasing mode. This resonant enhancement, contrary
to what is expected from the Purcell effect observed in the cavities, is then
manipulated by altering the cavity design and dimensions.",0509500v1
2006-06-03,Sign changes and resonance of intrinsic spin Hall effect in two-dimensional hole gas,"The intrinsic spin Hall conductance shows rich sign changes by applying a
perpendicular magnetic field in a two-dimensional hole gas. Especially, a
notable sign changes can be achieved by adjusting the characteristic length of
the Rashba coupling and hole density at moderate magnetic fields. This sign
issue may be easily realized in experiments. The oscillations of the intrinsic
spin Hall conductance as a function of 1/$B$ is nothing else but Shubnikov-de
Haas oscillations, and the additional beatings can be quantitatively related to
the value of the spin-orbit coupling parameter. The Zeeman splitting is too
small to introduce effective degeneracy between different Landau levels in a
two-dimensional hole gas, and the resonant intrinsic spin Hall conductance
appears in high hole density and strong magnetic field due to the transition
between mostly spin-$-{1/2}$ holes and spin-3/2 holes is confirmed. Two likely
ways to establish intrinsic spin Hall effect in experiments and a possible
application are suggested.",0606089v2
2006-07-25,Transport and recombination through weakly coupled localized spin pairs in semiconductors during coherent spin excitation,"Semi-analytical predictions for the transients of spin-dependent transport
and recombination rates through localized states in semiconductors during
coherent electron spin excitation are made for the case of weakly spin-coupled
charge carrier ensembles. The results show that the on-resonant Rabi frequency
of electrically or optically detected spin-oscillation doubles abruptly as the
strength of the resonant microwave field gamma B_1 exceeds the Larmor frequency
separation within the pair of charge carrier states between which the transport
or recombination transition takes place. For the case of a Larmor frequency
separation of the order of gamma B_1 and arbitrary excitation frequencies, the
charge carrier pairs exhibit four different nutation frequencies. From the
calculations, a simple set of equations for the prediction of these frequencies
is derived.",0607627v1
2006-10-03,Theory of nonlinear optical spectroscopy of electron spin coherence in quantum dots,"We study in theory the generation and detection of electron spin coherence in
nonlinear optical spectroscopy of semiconductor quantum dots doped with single
electrons. In third-order differential transmission spectra, the inverse width
of the ultra-narrow peak at degenerate pump and probe frequencies gives the
spin relaxation time ($T_1$), and that of the Stoke and anti-Stoke spin
resonances gives the effective spin dephasing time due to the inhomogeneous
broadening ($T_2^*$). The spin dephasing time excluding the inhomogeneous
broadening effect ($T_2$) is measured by the inverse width of ultra-narrow
hole-burning resonances in fifth-order differential transmission spectra.",0610075v1
2003-12-01,Preparing high purity initial states for nuclear magnetic resonance quantum computing,"Here we demonstrate how para-hydrogen can be used to prepare a two-spin
system in an almost pure state which is suitable for implementing nuclear
magnetic resonance (NMR) quantum computation. A 12ns laser pulse is used to
initiate a chemical reaction involving pure para-hydrogn (the nuclear spin
singlet of H2). The product, formed on the microsecond timescale, contains a
hydrogen derived two-spin system with an effective spin-state purity of 0.916.
To achieve a comparable result by direct cooling would require an unmanageable
(in the liquid state) effective spin temperature of 6.4mK or an impractical
magnetic field of 0.45MT at room temperature. The resulting spin state has an
entanglement of formation of 0.822 and cannot be described by local hidden
variable models.",0312014v4
2006-08-29,Room-temperature manipulation and decoherence of a single spin in diamond,"We report on room-temperature coherent manipulation of the spin of a single
nitrogen-vacancy center in diamond and a study of its coherence as a function
of magnetic field. We use magnetic resonance to induce Rabi nutations, and
apply a Hahn spin echo to remove the effect of low-frequency dephasing. A sharp
rise in the decoherence rate is observed at magnetic fields where the
nitrogen-vacancy center spin couples resonantly to substitutional nitrogen
spins via the magnetic dipolar coupling. Finally, we find evidence that away
from these energy resonances spin flips of nitrogen electrons are the main
source of decoherence.",0608233v2
2007-06-11,Theory of Neutron Scattering in High-T$_c$ Cuprates: Two Component Spin-Fermion Model,"Recent neutron scattering experiments have revealed that the generic form of
the magnetic excitations in the high-Tc cuprates of wide range of doping has
the so-called ""hourglass"" shape; it features both upward and downward
excitations at the incommensurate (IC) momenta spanning from the resonance peak
at the commensurate momentum $(\pi,\pi)$. We propose the two-component
spin-fermion model as a minimal phenomenological model which has both local
spins and itinerant fermions as independent degrees of freedom. Our
calculations of the dynamic spin correlation function provide good agreement
with experiments and show: (1) the upward dispersion branch of magnetic
excitations is mostly due to the local spin excitations; (2) the downward
dispersion branch is from collective spin excitations of fermions; (3) the
resonance mode is a mixture of both degrees of freedom.",0706.1387v2
2009-05-11,"Hyperfine interaction mediated exciton spin relaxation in (In,Ga)As quantum dots","The population dynamics of dark and bright excitons in (In,Ga)As/GaAs quantum
dots is studied by two-color pump-probe spectroscopy in an external magnetic
field. With the field applied in Faraday geometry and at T<20 K, the dark
excitons decay on a ten nanoseconds time scale unless the magnetic field
induces a resonance with a bright exciton state. At these crossings their
effective lifetime is drastically shortened due to spin flips of either
electron or hole by which the dark excitons are converted into bright ones. Due
to the quasielastic character we attribute the origin of these flips to the
hyperfine interaction with the lattice nuclei. We compare the exciton spin
relaxation times in the two resonances and find that the spin flip involving an
electron is approximately 25 times faster than the one of the hole. A
temperature increase leads to a considerable, nonmonotonic decrease of the dark
exciton lifetime. Here phonon-mediated spin flips due to the spin-orbit
interaction gradually become more important.",0905.1586v2
2009-07-06,Skyrme-Rpa Description of Spin-Flip M1 Giant Resonance,"The spin-flip M1 giant resonance is explored in the framework of Random Phase
Approximation on the basis of the Skyrme energy functional. A representative
set of eight Skyrme parameterizations (SkT6, SkM*, SLy6, SG2, SkO, SkO', SkI4,
and SV-bas) is used. Light and heavy, spherical and deformed nuclei ($^{48}$Ca,
$^{158}$Gd, $^{208}$Pb, and $^{238}$U) are considered. The calculations show
that spin densities play a crucial role in forming the collective shift in the
spectrum. The interplay of the collective shift and spin-orbit splitting
determines the quality of the description. None of the considered Skyrme
parameterizations is able to describe simultaneously the M1 strength
distribution in closed-shell and open-shell nuclei. It is found that the
problem lies in the relative positions of proton and neutron spin-orbit
splitting. Necessity to involve the tensor and isovector spin-orbit interaction
is called for.",0907.0923v1
2009-07-12,Why could Electron Spin Resonance be observed in a heavy fermion Kondo lattice?,"We develop a theoretical basis for understanding the spin relaxation
processes in Kondo lattice systems with heavy fermions as experimentally
observed by electron spin resonance (ESR). The Kondo effect leads to a common
energy scale that regulates a logarithmic divergence of different spin kinetic
coefficients and supports a collective spin motion of the Kondo ions with
conduction electrons. We find that the relaxation rate of a collective spin
mode is greatly reduced due to a mutual cancelation of all the divergent
contributions even in the case of the strongly anisotropic Kondo interaction.
The contribution to the ESR linewidth caused by the local magnetic field
distribution is subject to motional narrowing supported by ferromagnetic
correlations. The developed theoretical model successfully explains the ESR
data of YbRh2Si2 in terms of their dependence on temperature and magnetic
field.",0907.2074v2
2009-12-10,Coupled-channel calculation of bound and resonant spectra of Lambda-9Be and Lambda-13C hypernuclei,"A Multi-Channel Algebraic Scattering (MCAS) approach has been used to analyze
the spectra of two hyper-nuclear systems, Lambda-9Be and Lambda-13C. The
splitting of the two odd-parity excited levels (1/2^- and 3/2^-) at 11 MeV
excitation in Lambda-13C is driven mainly by the weak Lambda-nucleus spin-orbit
force, but the splittings of the 3/2^+ and 5/2^+ levels in both Lambda-9Be and
Lambda-13C have a different origin. These cases appear to be dominated by
coupling to the collective 2+ states of the core nuclei. Using simple
phenomenological potentials as input to the MCAS method, the observed splitting
and level ordering in Lambda-9Be is reproduced with the addition of a weak
spin-spin interaction acting between the hyperon and the spin of the excited
target. With no such spin-spin interaction, the level ordering in Lambda-9Be is
inverted with respect to that currently observed. In both hyper-nuclei, our
calculations suggest that there are additional low-lying resonant states in the
Lambda-nucleus continua.",0912.1970v1
2010-01-22,Spin-flip M1 giant resonance as a challenge for Skyrme forces,"Despite a great success of the Skyrme mean-field approach in exploration of
nuclear dynamics, it seems to fail in description of the spin-flip M1 giant
resonance. The results for different Skyrme parameterizations are contradictory
and poorly agree with experiment. In particular, there is no parameterization
which simultaneously describes the one-peak gross structure of M1 strength in
doubly magic nuclei and two-peak structure in heavy deformed nuclei. The reason
of this mismatch could lie in an unsatisfactory treatment of spin correlations
and spin-orbit interaction. We discuss the present status of the problem and
possible ways of its solution. In particular, we inspect i) the interplay of
the collective shift and spin-orbit splitting, ii) the isovector M1 response
versus isospin-mixed responses, and iii) the role of tensor and isovector
spin-orbit interaction.",1001.3965v1
2010-03-02,Inelastic neutron scattering and frequency domain magnetic resonance studies of S=4 and S=12 Mn$_6$ single-molecule magnets,"We investigate the magnetic properties of three Mn$_6$ single molecule
magnets by means of inelastic neutron scattering and frequency domain magnetic
resonance spectroscopy. The experimental data reveal that small structural
distortions of the molecular geometry produce a significant effect on the
energy level diagram and therefore on the magnetic properties of the molecule.
We show that the giant spin model completely fails to describe the spin level
structure of the ground spin multiplets. We analyze theoretically the spin
Hamiltonian for the low spin Mn$_6$ molecule (S=4) and we show that the excited
$S$ multiplets play a key role in determining the effective energy barrier for
the magnetization reversal, in analogy to what was previously found for the two
high spin Mn6 (S=12) molecules [S. Carretta et al., Phys. Rev. Lett. 100,
157203 (2008)].",1003.0537v1
2010-04-21,Magnetic strong coupling in a spin-photon system and transition to classical regime,"We study the energy level structure of the Tavis-Cumming model applied to an
ensemble of independent magnetic spins $s=1/2$ coupled to a variable number of
photons. Rabi splittings are calculated and their distribution is analyzed as a
functin of photon number $n_{\rm max}$ and spin system size $N$. A sharp
transition in the distribution of the Rabi frequency is found at $n_{\rm
max}\approx N$. The width of the Rabi frequency spectrum diverges as $\sqrt{N}$
at this point. For increased number of photons $n_{\rm max}>N$, the Rabi
frequencies converge to a value proportional to $\sqrt{n_{\rm max}}$. This
behavior is interpreted as analogous to the classical spin resonance mechanism
where the photon is treated as a classical field and one resonance peak is
expected. We also present experimental data demonstrating cooperative, magnetic
strong coupling between a spin system and photons, measured at room
temperature. This points towards quantum computing implementation with magnetic
spins, using cavity quantum-electrodynamics techniques.",1004.3605v2
2010-05-03,Electron transport in waveguides with spatially modulated strengths of the Rashba and Dresselhaus terms of the spin-orbit interaction,"We study electron transport through waveguides (WGs) in which the strengths
of the Rashba ($\alpha$) and Dresselhaus ($\beta$) terms of the spin-orbit
interaction (SOI) vary in space. Subband mixing, due to lateral confinement, is
taken into account only between the two first subbands. For sufficiently narrow
WGs the transmission $T$ exhibits a square-like shape as a function of $\alpha$
or $\beta$. Particular attention is paid to the case of equal SOI strengths,
$\alpha=\beta$, for which spin-flip processes are expected to decrease. The
transmission exhibits resonances as a function of the length of a SOI-free
region separating two regions with SOI present, that are most pronounced for
$\alpha=\beta$. The sign of $\alpha$ strongly affects the spin-up and spin-down
transmissions. The results show that the main effect of subband mixing is to
shift the transmission resonances and to decrease the transmission from one
spin state to another. The effect of possible band offsets between regions that
have different SOI strengths and effective masses is also discussed.",1005.0309v1
2010-06-10,Antiferromagnetically spin polarized oxygen observed in magneto-electric TbMn2O5,"We report the direct measurement of antiferromagnetic spin polarization at
the oxygen sites in the multiferroic TbMn2O5, through resonant soft x-ray
magnetic scattering. This supports recent theoretical models suggesting that
the oxygen spin polarization is key to the magnetoelectric coupling mechanism.
The spin polarization is observed through a resonantly enhanced diffraction
signal at the oxygen K edge at the commensurate antiferromagnetic wavevector.
Using the fdmnes code we have accurately reproduced the experimental data. We
have established that the resonance arises through the spin polarization on the
oxygen sites hybridized with the square based pyramid Mn3+ ions. Furthermore we
have discovered that the position of the Mn3+ ion directly influences the
oxygen spin polarization.",1006.1992v1
2011-01-11,Analog of Electromagnetically Induced Transparency Effect for Two Nano/Micro-mechanical Resonators Coupled With Spin Ensemble,"We study a hybrid nano-mechanical system coupled to a spin ensemble as a
quantum simulator to favor a quantum interference effect, the
electromagnetically induced transparency (EIT). This system consists of two
nano-mechanical resonators (NAMRs), each of which coupled to a nuclear spin
ensemble. It could be regarded as a crucial element in the quantum network of
NAMR arrays coupled to spin ensembles. Here, the nuclear spin ensembles behave
as a long-lived transducer to store and transfer the NAMRs' quantum
information. This system shows the analog of EIT effect under the driving of a
probe microwave field. The double-EIT phenomenon emerges in the large $N$ (the
number of the nuclei) limit with low excitation approximation, because the
interactions between the spin ensemble and the two NAMRs are reduced to the
coupling of three harmonic oscillators. Furthermore, the group velocity is
reduced in the two absorption windows.",1101.2115v1
2011-02-10,Stimulated emission and absorption of photons in magnetic point contacts: toward metal-based spin-lasers,"Point contacts between high anisotropy ferromagnetic SmCo5 and normal metal
Cu are used to achieve a strong spin-population inversion in the contact core.
Subjected to microwave irradiation in resonance with the Zeeman splitting in
Cu, the inverted spin-population relaxes through stimulated spin-flip photon
emission, detected as peaks in the point contact resistance. Resonant spin-flip
photon absorption is detected as resistance minima, corresponding to sourcing
the photon field energy into the electrical circuit. These results demonstrate
fundamental mechanisms that are potentially useful for designing metallic
spin-based lasers.",1102.2167v1
2011-05-07,Field Tuning the G-Factor in InAs Nanowire Double Quantum Dots,"We study the effects of magnetic and electric fields on the g-factors of
spins confined in a two-electron InAs nanowire double quantum dot. Spin
sensitive measurements are performed by monitoring the leakage current in the
Pauli blockade regime. Rotations of single spins are driven using
electric-dipole spin resonance. The g-factors are extracted from the spin
resonance condition as a function of the magnetic field direction, allowing
determination of the full g-tensor. Electric and magnetic field tuning can be
used to maximize the g-factor difference and in some cases altogether quench
the EDSR response, allowing selective single spin control.",1105.1462v2
2011-05-26,Bloch-oscillations of exciton-polaritons and photons for the generation of an alternating terahertz spin current,"We analyze theoretically the spin dynamics of exciton-polaritons and photons
during their Bloch oscillations in a one-dimensional microwire. The wire
geometry induces an energy splitting between the longitudinal and transverse
electric polarized eigenmodes. We show analytically that a synchronized regime
between the Bloch oscillations in space and the precession of the pseudospin
can be achieved. This synchronization results in the formation of a THz
alternating spin current which can be extracted out of the confinement region
by the Landau-Zener tunneling towards the second allowed miniband. Finally we
show how the spin signal can be maintained despite of the lifetime of the
particles for the case of exciton-polaritons both in a resonant and non
resonant pumping schemes. The structure therefore acts as a Spin-optronic
device able to convert the polarization and emit spin polarized pulses.",1105.5278v1
2011-06-15,Proposal for detecting spin-chirality terms in Mott insulators via resonant inelastic x-ray scattering,"We consider the question of whether resonant inelastic x-ray scattering
(RIXS) can be used to detect many-body excitations that are coupled to the
spin-chirality terms S_i . (S_j x S_k) in a Mott insulator. We find that while
the spin-chirality terms are in general absent in the usual experimental setups
of RIXS, there are prospects of realizing such terms if one considers instead
the scattering near a pre-edge. We then perform detailed analyses for the
square and the kagome lattices, and brief analyses for the triangular and the
honeycomb lattices, in which we show that the spin-chirality terms are indeed
present in all the above lattices, but that they occur at a higher order in our
expansion for the kagome and the honeycomb lattices. The merit of using RIXS in
addition to Raman spectroscopy to detect excitations that are coupled to the
spin-chirality terms is also briefly discussed in the context of the emergent
gauge boson in the U(1) Dirac spin liquid.",1106.3108v2
2011-10-29,Mechanism of half-frequency electric dipole spin resonance in double quantum dots: Effect of nonlinear charge dynamics inside the singlet manifold,"Electron dynamics in quantum dots manifests itself in spin-flip spectra
through electric dipole spin resonance (EDSR). Near a neutrality point
separating two different singlet charged states of a double quantum dot, charge
dynamics inside a $2\times2$ singlet manifold can be described by a
1/2-pseudospin. In this region, charge dynamics is highly nonlinear and
strongly influenced by flopping its soft pseudospin mode. As a result, the
responses to external driving include first and second harmonics of the driving
frequency and their Raman satellites shifted by the pseudospin frequency. In
EDSR spectra of a spin-orbit couplet doublet dot, they manifest themselves as
charge satellites of spin-flip transitions. The theory describes gross features
of the anomalous half-frequency EDSR in spin blockade spectra [Laird et al.,
Semicond. Sci. Techol. {\bf 24}, 064004 (2009)].",1110.6569v2
2011-11-05,Coherent storage of photoexcited triplet states using 29Si nuclear spins in silicon,"Pulsed electron paramagnetic resonance spectroscopy of the photoexcited,
metastable triplet state of the oxygen-vacancy center in silicon reveals that
the lifetime of the ms = \pm1 sub-levels differ significantly from that of the
ms =0 state. We exploit this significant difference in decay rates to the
ground singlet state to achieve nearly ~100% electron spin polarization within
the triplet. We further demonstrate the transfer of a coherent state of the
triplet electron spin to, and from, a hyperfine-coupled, nearest-neighbor 29Si
nuclear spin. We measure the coherence time of the 29 Si nuclear spin employed
in this operation and find it to be unaffected by the presence of the triplet
electron spin and equal to the bulk value measured by nuclear magnetic
resonance.",1111.1344v1
2012-01-18,Crossover from coherent to incoherent scattering in spin-orbit dominated Sr2IrO4,"Strong spin-orbit interaction in the two dimensional compound Sr2IrO4 leads
to the formation of Jeff=1/2 isospins with unprecedented dynamics. In Raman
scattering a continuum attributed to double spin scattering is observed. With
higher excitation energy of the incident Laser this signal crosses over to an
incoherent background. The characteristic energy scale of this cross over is
identical to that of intensity resonance effects in phonon scattering. It is
related to exciton-like orbital excitations that are also evident in resonant
X-Ray scattering. The crossover and evolution of incoherent excitations are
proposed to be due to their coupling to spin excitations. This signals a
spin-orbit induced entanglement of spin, lattice and charge degrees of freedoms
in Sr2IrO4.",1201.3841v1
2012-10-21,Spin-dependent exciton quenching and intrinsic spin coherence in CdSe/CdS nanocrystals,"Large surface to volume ratios of semiconductor nanocrystals cause
susceptibility to charge trapping, which can modify luminescence yields and
induce single-particle blinking. Optical spectroscopies cannot differentiate
between bulk and surface traps in contrast to spin-resonance techniques, which
in principle avail chemical information on such trap sites. Magnetic resonance
detection via spin-controlled photoluminescence enables the direct observation
of interactions between emissive excitons and trapped charges. This approach
allows the discrimination of two functionally different trap states in CdSe/CdS
nanocrystals underlying the fluorescence quenching and thus blinking
mechanisms: a spin-dependent Auger process in charged particles; and a
charge-separated state pair process, which leaves the particle neutral. The
paramagnetic trap centers offer control of energy transfer from the wide-gap
CdS to the narrow-gap CdSe, i.e. light harvesting within the heterostructure.
Coherent spin motion within the trap states of the CdS arms of nanocrystal
tetrapods is reflected by spatially remote luminescence from CdSe cores with
surprisingly long coherence times of >300 ns at 3.5 K.",1210.5684v1
2013-01-28,Spin filter effect at room temperature in GaN/GaMnN ferromagnetic resonant tunneling diode,"We have investigated the spin current polarization without the external
magnetic field in the resonant tunneling diode with the emitter and quantum
well layers made from the ferromagnetic GaMnN. For this purpose we have applied
the self-consistent Wigner-Poisson method and studied the spin-polarizing
effect of the parallel and antiparallel alignment of the magnetization in the
ferromagnetic layers. The results of our calculations show that the
antiparallel magnetization is much more advantageous for the spin filter
operation and leads to the full spin current polarization at low temperatures
and 35 % spin polarization of the current at room temperature.",1301.6544v1
2013-02-07,Quantum bath-driven decoherence of mixed spin systems,"The decoherence of mixed electron-nuclear spin qubits is a topic of great
current importance, but understanding is still lacking: while important
decoherence mechanisms for spin qubits arise from quantum spin bath
environments with slow decay of correlations, the only analytical framework for
explaining observed sharp variations of decoherence times with magnetic field
is based on the suppression of classical noise. Here we obtain a general
expression for decoherence times of the central spin system which exposes
significant differences between quantum-bath decoherence and decoherence by
classical field noise. We perform measurements of decoherence times of bismuth
donors in natural silicon using both electron spin resonance (ESR) and nuclear
magnetic resonance (NMR) transitions, and in both cases find excellent
agreement with our theory across a wide parameter range. The universality of
our expression is also tested by quantitative comparisons with previous
measurements of decoherence around `optimal working points' or `clock
transitions' where decoherence is strongly suppressed. We further validate our
results by comparison to cluster expansion simulations.",1302.1709v4
2013-08-16,Persistent spin excitations in doped antiferromagnets revealed by resonant inelastic light scattering,"How coherent quasiparticles emerge by doping quantum antiferromagnets is a
key question in correlated electron systems, whose resolution is needed to
elucidate the phase diagram of copper oxides. Recent resonant inelastic X-ray
scattering (RIXS) experiments in hole-doped cuprates have purported to measure
high-energy collective spin excitations that persist well into the overdoped
regime and bear a striking resemblance to those found in the parent compound,
challenging the perception that spin excitations should weaken with doping and
have a diminishing effect on superconductivity. Here we show that RIXS at the
Cu L3-edge indeed provides access to the spin dynamical structure factor once
one considers the full influence of light polarization. Further we demonstrate
that high-energy spin excitations do not correlate with the doping dependence
of Tc, while low-energy excitations depend sensitively on doping and show
ferromagnetic correlations. This suggests that high-energy spin excitations are
marginal to pairing in cuprate superconductors.",1308.3717v2
2013-10-16,Terahertz out-of-plane resonances due to spin-orbit coupling,"A microscopic kinetic theory is developed which allows to investigate
non-Abelian SU(2) systems interacting with meanfields and spin-orbit coupling
under magnetic fields in one, two, and three dimensions. The coupled kinetic
equations for the scalar and spin components are presented and linearized with
respect to an external electric field. The dynamical classical and quantum Hall
effect are described in this way as well as the anomalous Hall effect where a
new symmetric dynamical contribution to the conductivity is presented. The
coupled density and spin response functions to an electric field are derived
including arbitrary magnetic fields. The magnetic field induces a staircase
structure at frequencies of the Landau levels. It is found that for linear
Dresselhaus and Rashba spin-orbit coupling a dynamical out-of-plane spin
response appears at these Landau level frequencies establishing terahertz
resonances.",1310.4405v1
2013-12-21,Optically Detected Cross-Relaxation Spectroscopy of Electron Spins in Diamond,"The application of magnetic resonance (MR) spectroscopy at progressively
smaller length scales may eventually permit ""chemical imaging"" of spins at the
surfaces of materials and biological complexes. In particular, the negatively
charged nitrogen-vacancy (NV-) centre in diamond has been exploited as an
optical transducer for nanoscale nuclear magnetic resonance. However, the
spectra of detected spins are generally broadened by their interaction with
proximate paramagnetic NV- centres through coherent and incoherent mechanisms.
Here we demonstrate a detection technique that can resolve the spectra of
electron spins coupled to NV- centres, namely substitutional nitrogen (NS) and
neutral nitrogen-vacancy (NV0) centres in diamond, through optically detected
cross-relaxation. The hyperfine spectra of these spins are a unique chemical
identifier, suggesting the possibility, in combination with recent results in
diamonds harbouring shallow NV- implants, that the spectra of spins external to
the diamond can be similarly detected.",1312.6313v1
2014-02-25,A quantum mechanical NMR simulation algorithm for protein-scale spin systems,"Nuclear magnetic resonance spectroscopy is one of the few remaining areas of
physical chemistry for which polynomially scaling simulation methods have not
so far been available. Here, we report such a method and illustrate its
performance by simulating common 2D and 3D liquid state NMR experiments
(including accurate description of spin relaxation processes) on isotopically
enriched human ubiquitin - a protein containing over a thousand nuclear spins
forming an irregular polycyclic three-dimensional coupling lattice. The
algorithm uses careful tailoring of the density operator space to only include
nuclear spin states that are populated to a significant extent. The reduced
state space is generated by analyzing spin connectivity and decoherence
properties: rapidly relaxing states as well as correlations between
topologically remote spins are dropped from the basis set. In the examples
provided, the resulting reduction in the quantum mechanical simulation time is
by many orders of magnitude.",1402.6139v1
2015-01-22,Incoherent excitation and switching of spin states in exciton-polariton condensates,"We investigate, theoretically and numerically, the spin dynamics of a
two-component exciton-polariton condensate created and sustained by
non-resonant spin-polarized optical pumping of a semiconductor microcavity.
Using the open-dissipative mean-field model, we show that the existence of well
defined phase-locked steady states of the condensate may lead to efficient
switching and control of spin (polarization) states with a non-resonant
excitation. Spatially inhomogeneous pulsed excitations can cause symmetry
breaking in the pseudo-spin structure of the condensate and lead to formation
of non-trivial spin textures. Our model is universally applicable to two weakly
coupled polariton condensates, and therefore can also describe the behaviour of
condensate populations and phases in 'double-well' type potentials.",1501.05355v1
2015-02-25,Observation of a phononic Mollow triplet in a hybrid spin-nanomechanical system,"Reminiscent of the bound character of a qubit's dynamics confined on the
Bloch sphere, the observation of a Mollow triplet in the resonantly driven
qubit fluorescence spectrum represents one of the founding signatures of
Quantum Electrodynamics. Here we report on its observation in a hybrid
spin-nanomechanical system, where a Nitro-gen Vacancy spin qubit is
magnetically coupled to the vibrations of a Silicon Carbide nanowire. A
resonant microwave field turns the originally parametric hybrid interac-tion
into a resonant process, where acoustic phonons are now able to induce
transitions between the dressed qubit states, leading to synchronized
spin-oscillator dynamics. We further explore the vectorial character of the
hybrid coupling to the bidimensional de-formations of the nanowire. The
demonstrated microwave assisted synchronization of the spin-oscillator dynamics
opens novel perspectives for the exploration of spin-dependent forces, the
key-ingredient for quantum state transfer.",1502.07071v1
2015-05-07,Electronic spin susceptibilities and superconductivity in HgBa$_{2}$CuO$_{4+δ}$ from nuclear magnetic resonance,"Nuclear magnetic resonance (NMR) experiments on single crystals of
HgBa$_{2}$CuO$_{4+\delta}$ are presented that identify two distinct
temperature-dependent spin susceptibilities: one is due to a spin component
that is temperature-dependent above the critical temperature for
superconductivity ($T_{\rm c}$) and reflects pseudogap behavior; the other is
Fermi-liquid-like in that it is temperature independent above $T_{\rm c}$ and
vanishes rapidly below $T_{\rm c}$. In addition, we demonstrate the existence
of a third, hitherto undetected spin susceptibility: it is temperature
independent at higher temperatures, vanishes at lower temperatures (below
$T_0\neq T_{\rm c}$), and changes sign near optimal doping. This susceptibility
either arises from the coupling between the two spin components, or it could be
given by a distinct third spin component.",1505.01725v1
2015-06-26,Spin-dependent coherent transport in a double quantum dot system,"We study spin-resolved resonant tunneling in a system of two quantum dots
sandwiched between doped quantum wells. In the coherent (Dicke) regime, i.e.,
when quantum dot separation is smaller than the Fermi wavelength in a
two-dimensional electron gas in quantum wells, application of an in-plane
magnetic field leads to a pronounced spin-resolved structure of the conductance
peak lineshape even for very small Zeeman splitting of the quantum dots'
resonant levels. In the presence of electron-gas spin-orbit coupling, this
spin-resolved structure gets washed out due to Fermi surface deformation in the
momentum space. We also show that Aharonov-Bohm flux penetrating the area
enclosed by electron tunneling pathways completely destroys conductance spin
structure.",1506.08214v2
2015-10-13,Spin liquid phases of Mott insulating ultracold bosons,"Mott insulating ultracold gases posses a unique whole-atom exchange
interaction which enables large quantum fluctuations between the Zeeman
sublevels of each atom. By strengthening this interaction---either through the
use of large-spin atoms, or by tuning the particle-particle interactions via
optical Feshbach resonance---one may enhance fluctuations and facilitate the
appearance of the long sought-after quantum spin liquid phase---all in the
highly tunable environment of cold atoms. To illustrate the relationship
between the spin magnitude, interaction strength, and resulting magnetic
phases, we present and solve a mean field theory for bosons optically confined
to the one particle-per-site Mott state, using both analytic and numerical
methods. We find on a square lattice with bosons of hyperfine spin $f>2$, that
making the repulsive s-wave scattering length through the singlet channel
small---relative to the higher-order scattering channels---accesses a
short-range resonating valence bond (s-RVB) spin liquid phase.",1510.03851v1
2015-10-22,Electron spin control of optically levitated nanodiamonds in vacuum,"Electron spins of diamond nitrogen-vacancy (NV) centers are important quantum
resources for nanoscale sensing and quantum information. Combining NV spins
with levitated optomechanical resonators will provide a hybrid quantum system
for novel applications. Here we optically levitate a nanodiamond and
demonstrate electron spin control of its built-in NV centers in low vacuum. We
observe that the strength of electron spin resonance (ESR) is enhanced when the
air pressure is reduced. To better understand this system, we investigate the
effects of trap power and measure the absolute internal temperature of
levitated nanodiamonds with ESR after calibration of the strain effect. We also
observe that oxygen and helium gases have different effects on both the
photoluminescence and the ESR contrast of nanodiamond NV centers, indicating
potential applications of NV centers in oxygen gas sensing. Our results pave
the way towards a levitated spin-optomechanical system for studying macroscopic
quantum mechanics.",1510.06715v2
2015-11-16,Electron paramagnetic resonance spectroscopy using a dc-SQUID magnetometer directly coupled to an electron spin ensemble,"We demonstrate electron spin polarization detection and electron paramagnetic
resonance (EPR) spectroscopy using a direct current superconducting quantum
interference device (dc-SQUID) magnetometer. Our target electron spin ensemble
is directly glued on the dc-SQUID magnetometer that detects electron spin
polarization induced by a external magnetic field or EPR in micrometer-sized
area. The minimum distinguishable number of polarized spins and sensing volume
of the electron spin polarization detection and the EPR spectroscopy are
estimated to be $\sim$$10^6$ and $\sim$$10^{-10}$ $\mathrm{cm}^{3}$ ($\sim$0.1
pl), respectively.",1511.04832v1
2016-01-08,Detecting the orbital character of the spin fluctuation in the Iron-based superconductors with the resonant inelastic X-ray scattering spectroscopy,"The orbital distribution of the spin fluctuation in the iron-based
superconductors(IBSs) is the key information needed to understand the
magnetism, superconductivity and electronic nematicity in these multi-orbital
systems. In this work, we propose that the resonant inelastic X-ray
scattering(RIXS) technique can be used to probe selectively the spin
fluctuation on different Fe $3d$ orbitals. In particular, the spin fluctuation
on the three $t_{2g}$ orbitals, namely, the $3d_{xz}$, $3d_{yz}$ and the
$3d_{xy}$ orbital, can be selectively probed in the $\sigma\rightarrow\pi'$
scattering geometry by aligning the direction of the outgoing photon in the
$y$, $x$ and $z$ direction. Such orbital-resolved information on the spin
fluctuation is invaluable for the study of the orbital-selective physics in the
IBSs and can greatly advance our understanding on the relation between orbital
ordering and spin nematicity in the IBSs and the orbital-selective pairing
mechanism in these multi-orbital systems.",1601.01809v3
2016-05-11,Resonant inelastic X-ray scattering response of the Kitaev honeycomb model,"We calculate the resonant inelastic X-ray scattering (RIXS) response of the
Kitaev honeycomb model, an exactly solvable quantum-spin-liquid model with
fractionalized Majorana and flux excitations. We find that the fundamental RIXS
channels, the spin-conserving (SC) and the non-spin-conserving (NSC) ones, do
not interfere and give completely different responses. SC-RIXS picks up
exclusively the Majorana sector with a pronounced momentum dispersion, whereas
NSC-RIXS also creates immobile fluxes, thereby rendering the response only
weakly momentum dependent, as in the spin structure factor measured by
inelastic neutron scattering. RIXS can therefore pick up the fractionalized
excitations of the Kitaev spin liquid separately, making it a sensitive probe
to detect spin-liquid character in potential material incarnations of the
Kitaev honeycomb model.",1605.03272v2
2017-12-13,Mobile bound states of Rydberg excitations in a lattice,"Spin lattice models play central role in the studies of quantum magnetism and
non-equilibrium dynamics of spin excitations -- magnons. We show that a spin
lattice with strong nearest-neighbor interactions and tunable long-range
hopping of excitations can be realized by a regular array of laser driven
atoms, with an excited Rydberg state representing the spin-up state and a
Rydberg-dressed ground state corresponding to the spin-down state. We find
exotic interaction-bound states of magnons that propagate in the lattice via
the combination of resonant two-site hopping and non-resonant second-order
hopping processes. Arrays of trapped Rydberg-dressed atoms can thus serve as a
flexible platform to simulate and study fundamental few-body dynamics in spin
lattices.",1712.04713v1
2018-05-10,Understanding Spin Configuration in the Geometrically Frustrated Magnet TbB$_{4}$: a Resonant Soft X-ray Scattering Study,"The frustrated magnet has been regarded as a system that could be a promising
host material for the quantum spin liquid (QSL). However, it is difficult to
determine the spin configuration and the corresponding mechanism in this
system, because of its geometrical frustration (i.e., crystal structure and
symmetry). Herein, we systematically investigate one of the geometrically
frustrated magnets, the TbB$_{4}$ compound. Using resonant soft x-ray
scattering (RSXS), we explored its spin configuration, as well as Tb's
quadrupole. Comprehensive evaluations of the temperature and photon energy /
polarization dependences of the RSXS signals reveal the mechanism of spin
reorientation upon cooling down, which is the sophisticated interplay between
the Tb spin and the crystal symmetry rather than its orbit (quadrupole). Our
results and their implications would further shed a light on the search for
possible realization of QSL.",1805.04209v1
2018-05-15,Spin-orbit coupling and electric-dipole spin resonance in a nanowire double quantum dot,"We study the electric-dipole transitions for a single electron in a double
quantum dot located in a semiconductor nanowire. Enabled by spin-orbit coupling
(SOC), electric-dipole spin resonance (EDSR) for such an electron can be
generated via two mechanisms: the SOC-induced intradot pseudospin states mixing
and the interdot spin-flipped tunneling. The EDSR frequency and strength are
determined by these mechanisms together. For both mechanisms the
electric-dipole transition rates are strongly dependent on the external
magnetic field. Their competition can be revealed by increasing the magnetic
field and/or the interdot distance for the double dot. To clarify whether the
strong SOC significantly impact the electron state coherence, we also calculate
relaxations from excited levels via phonon emission. We show that spin-flip
relaxations can be effectively suppressed by the phonon bottleneck effect even
at relatively low magnetic fields because of the very large $g$-factor of
strong SOC materials such as InSb.",1805.05541v1
2018-11-03,Resonant optical spin initialization and readout of single silicon vacancies in 4H-SiC,"The silicon monovacancy in 4H-SiC is a promising candidate for solid-state
quantum information processing. We perform high-resolution optical spectroscopy
on single V2 defects at cryogenic temperatures. We find favorable low
temperature optical properties that are essential for optical readout and
coherent control of its spin and for the development of a spin-photon
interface. The common features among individual defects include two narrow,
nearly lifetime-limited optical transitions that correspond to $m_s{=}\pm 3/2$
and $m_s{=}\pm 1/2$ spin states with no discernable zero-field splitting
fluctuations. Initialization and readout of the spin states is characterized by
time-resolved optical spectroscopy under resonant excitation of these
transitions, showing significant differences between the $\pm 3/2$ and $\pm
1/2$ spin states. These results are well-described by a theoretical model that
strengthens our understanding of the quantum properties of this defect.",1811.01293v2
2017-05-29,The neutral silicon-vacancy center in diamond: spin polarization and lifetimes,"We demonstrate optical spin polarization of the neutrally-charged
silicon-vacancy defect in diamond ($\mathrm{SiV^{0}}$), an $S=1$ defect which
emits with a zero-phonon line at 946 nm. The spin polarization is found to be
most efficient under resonant excitation, but non-zero at below-resonant
energies. We measure an ensemble spin coherence time $T_2>100~\mathrm{\mu s}$
at low-temperature, and a spin relaxation limit of $T_1>25~\mathrm{s}$. Optical
spin state initialization around 946 nm allows independent initialization of
$\mathrm{SiV^{0}}$ and $\mathrm{NV^{-}}$ within the same optically-addressed
volume, and $\mathrm{SiV^{0}}$ emits within the telecoms downconversion band to
1550 nm: when combined with its high Debye-Waller factor, our initial results
suggest that $\mathrm{SiV^{0}}$ is a promising candidate for a long-range
quantum communication technology.",1705.10205v1
2018-07-24,Exciton spin relaxation in InAs/InGaAlAs/InP(001) quantum dashes emitting near 1.55 μm,"Exciton spin and related optical polarization in self-assembled
InAs/In$_{0.53}$Ga$_{0.23}$Al$_{0.24}$As/InP(001) quantum dashes emitting at
1.55 {\mu}m are investigated by means of polarization- and time-resolved
photoluminescence, as well as photoluminescence excitation spectroscopy, at
cryogenic temperature. We investigate the influence of highly non-resonant and
quasi-resonant optical spin pumping conditions on spin polarization and spin
memory of the quantum dash ground state. We show that a spin pumping scheme,
utilizing the longitudinal-optical-phonon-mediated coherent scattering process,
can lead to the polarization degree above 50%. We discuss the role of intrinsic
asymmetries in the quantum dash that influence values of the degree of
polarization and its time evolution.",1807.09143v1
2018-10-29,Optimized electrical control of a Si/SiGe spin qubit in the presence of an induced frequency shift,"Electron spins confined in quantum dots are an attractive system to realize
high-fidelity qubits owing to their long coherence time. With the prolonged
spin coherence time, however, the control fidelity can be limited by systematic
errors rather than decoherence, making characterization and suppression of
their influence crucial for further improvement. Here we report that the
control fidelity of Si/SiGe spin qubits can be limited by the microwave-induced
frequency shift of electric dipole spin resonance and it can be improved by
optimization of control pulses. As we increase the control microwave amplitude,
we observe a shift of the qubit resonance frequency, in addition to the
increasing Rabi frequency. We reveal that this limits control fidelity with a
conventional amplitude-modulated microwave pulse below 99.8%. In order to
achieve a gate fidelity > 99.9%, we introduce a quadrature control method, and
validate this approach experimentally by randomized benchmarking. Our finding
facilitates realization of an ultra-high fidelity qubit with electron spins in
quantum dots.",1810.12040v1
2018-10-30,Constant-adiabaticity RF-pulses for generating long-lived singlet spin states in NMR,"A method is implemented to perform ""fast"" adiabatic variation of the spin
Hamiltonian by imposing the constant adiabaticity condition. The method is
applied to improve the performance of singlet-state Nuclear Magnetic Resonance
(NMR) experiments, specifically, for efficient generation and readout of the
singlet spin order in coupled spin pairs by applying adiabatically ramped
RF-fields. Test experiments have been performed on a specially designed
molecule having two strongly coupled C-13 spins and on selectively isotopically
labelled glycerol having two pairs of coupled protons. Optimized RF-ramps show
improved performance in comparison, for example, to linear ramps. We expect
that the methods described here are useful, not only for singlet-state NMR
experiments, but also for other experiments in magnetic resonance, which
utilize adiabatic variation of the spin Hamiltonian.",1810.12697v1
2016-03-09,Electric dipole spin resonance in systems with a valley dependent g-factor,"In this theoretical study we qualitatively and quantitatively investigate the
electric dipole spin resonance (EDSR) in a single Si/SiGe quantum dot in the
presence of a magnetic field gradient, e.g., produced by a ferromagnet. We
model a situation in which the control of electron spin states is achieved by
applying an oscillatory electric field, inducing real-space oscillations of the
electron inside the quantum dot. One of the goals of our study is to present a
microscopic theory of valley dependent $g$-factors in Si/SiGe quantum dots and
investigate how valley relaxation combined with a valley dependent $g$-factor
leads to a novel electron spin dephasing mechanism. Furthermore, we discuss the
interplay of spin and valley relaxations in Si/SiGe quantum dots. Our findings
suggest that the electron spin dephases due to valley relaxation, and are in
agreement with recent experimental studies [Nature Nanotechnology 9, 666-670
(2014)].",1603.02829v1
2017-06-20,Tuning an effective spin chain of three strongly interacting one-dimensional fermions with the transversal confinement,"Strongly interacting one-dimensional fermions form an effective spin chain in
the absence of an external lattice potential. We show that the exchange
coefficients of such a chain may be locally tuned by properly tailoring the
transversal confinement. In particular, in the vicinity of a
confinement-induced resonance (CIR) the exchange coefficients may have
simultaneously opposite ferromagnetic and antiferromagnetic characters at
different locations along the trap axis. Moreover, the local exchanges may be
engineered to induce avoided crossings between spin states at the CIR, and
hence a ramp across the resonance may be employed to create different spin
states and to induce spin dynamics in the chain. We show that such unusual spin
chains have already been realized in the experiment of Murmann et al. [Phys.
Rev. Lett. 115, 215301 (2015)].",1706.06513v2
2020-03-06,g-tensor resonance in double quantum dots with site-dependent g-tensors,"Pauli spin blockade (PSB) has long been an important tool for spin read-out
in double quantum dot (DQD) systems with interdot tunneling $t$. In this paper
we show that the blockade is lifted if the two dots experience distinct
effective magnetic fields caused by site-dependent g-tensors $g_L$ and $g_R$
for the left and right dot, and that this effect can be more pronounced than
the leakage current due to the spin-orbit interaction (SOI) via spin-flip
tunneling and the hyperfine interaction (HFI) of the electron spin with the
host nuclear spins. Using analytical results obtained in special parameter
regimes, we show that information about both the out-of-plane and in-plane
g-factors of the dots can be inferred from characteristic features of the
magneto-transport curve. For a symmetric DQD, we predict a pronounced maximum
in the leakage current at the characteristic out-of-plane magnetic field $B^* =
t/ \mu_B \sqrt{g_z^L g_z^R}$ which we term the g-tensor resonance of the
system. Moreover, we extend the results to contain the effects of strong SOI
and argue that in this more general case the leakage current carries
information about the g-tensor components and SOI of the system.",2003.03102v1
2020-09-25,Spin-selective resonant tunneling induced by Rashba spin-orbit interaction in semiconductor nanowire,"We consider a single electron confined within a quantum wire in a system of
two electrostatically-induced QDs defined by nearby gates. The time-varying
electric field, of single GHz frequency, perpendicular to the quantum wire, is
used to induce the Rashba coupling and enable spin-dependent resonant tunneling
of the electron between two adjacent potential wells with fidelity over 99.5%.
This effect can be used for the high fidelity all-electrical electron-spin
initialization or readout in the spin-based quantum computer. In contrast to
other spin initialization methods, our technique can be performed adiabatically
without increase in the energy of the electron. Our simulations are supported
by a realistic self-consistent time-dependent Poisson-Schroedinger
calculations.",2009.12439v2
2021-04-06,Spin-orbit enabled quantum transport channels in a two-hole double quantum dot,"We analyze experimentally and theoretically the transport spectra of a gated
lateral GaAs double quantum dot containing two holes. The strong spin-orbit
interaction present in the hole subband lifts the Pauli spin blockade and
allows to map out the complete spectra of the two-hole system. By performing
measurements in both source-drain voltage directions, at different detunings
and magnetic fields, we carry out quantitative fitting to a Hubbard two-site
model accounting for the tunnel coupling to the leads and the spin-flip
relaxation process. We extract the singlet-triplet gap and the magnetic field
corresponding to the singlet-triplet transition in the double-hole ground
state. Additionally, at the singlet-triplet transition we find a resonant
enhancement (in the blockaded direction) and suppression of current (in the
conduction direction). The current enhancement stems from the multiple
resonance of two-hole levels, opening several conduction channels at once. The
current suppression arises from the quantum interference of spin-conserving and
spin flipping tunneling processes.",2104.02568v1
2008-06-11,Excited-state spectroscopy using single-spin manipulation in diamond,"We use single-spin resonant spectroscopy to study the spin structure in the
orbital excited-state of a diamond nitrogen-vacancy center at room temperature.
We find that the excited state spin levels have a zero-field splitting that is
approximately half of the value of the ground state levels, a g-factor similar
to the ground state value, and a hyperfine splitting ~20x larger than in the
ground state. In addition, the width of the resonances reflects the electronic
lifetime in the excited state. We also show that the spin-splitting can
significantly differ between NV centers, likely due to the effects of local
strain, which provides a pathway to control over the spin Hamiltonian and may
be useful for quantum information processing.",0806.1939v1
2019-01-07,Stabilisation of an optical transition energy via nuclear Zeno dynamics in quantum dot-cavity systems,"We investigate the effect of nuclear spins on the phase shift and
polarisation rotation of photons scattered off a quantum dot-cavity system. We
show that as the phase shift depends strongly on the resonance energy of an
electronic transition in the quantum dot, it can provide a sensitive probe of
the quantum state of nuclear spins that broaden this transition energy. By
including the electron-nuclear spin coupling at a Hamiltonian level within an
extended input-output formalism, we show how a photon scattering event acts as
a nuclear spin measurement, which when rapidly applied leads to an inhibition
of the nuclear spin dynamics via the quantum Zeno effect, and a corresponding
stabilisation of the optical resonance. We show how such an effect manifests in
the intensity autocorrelation $g^{(2)}(\tau)$ of scattered photons, whose
long-time bunching behaviour changes from quadratic decay for low photon
scattering rates (weak laser intensities), to ever slower exponential decay for
increasing laser intensities as optical measurements impede the nuclear spin
evolution.",1901.01962v2
2019-04-30,Electric-field control and noise protection of the flopping-mode spin qubit,"We propose and analyze a novel ""flopping-mode"" mechanism for electric dipole
spin resonance based on the delocalization of a single electron across a double
quantum dot confinement potential. Delocalization of the charge maximizes the
electronic dipole moment compared to the conventional single dot spin resonance
configuration. We present a theoretical investigation of the flopping-mode spin
qubit properties through the crossover from the double to the single dot
configuration by calculating effective spin Rabi frequencies and single-qubit
gate fidelities. The flopping-mode regime optimizes the artificial spin-orbit
effect generated by an external micromagnet and draws on the existence of an
externally controllable sweet spot, where the coupling of the qubit to charge
noise is highly suppressed. We further analyze the sweet spot behavior in the
presence of a longitudinal magnetic field gradient, which gives rise to a
second order sweet spot with reduced sensitivity to charge fluctuations.",1904.13117v2
2019-10-27,Stochastic thermodynamics of an electron-spin-resonance quantum dot system,"We present a stochastic thermodynamics analysis of an electron-spin-resonance
pumped quantum dot device in the Coulomb-blocked regime, where a pure spin
current is generated without an accompanying net charge current. Based on a
generalized quantum master equation beyond secular approximation, quantum
coherences are accounted for in terms of an effective average spin in the
Floquet basis. Elegantly, this effective spin undergoes a precession about an
effective magnetic field, which originates from the non-secular treatment and
energy renormalization. It is shown that the interaction between effective spin
and effective magnetic field may have the dominant roles to play in both energy
transport and irreversible entropy production. In the stationary limit, the
energy and entropy balance relations are also established based on the theory
of counting statistics.",1910.12275v1
2020-10-27,Searching spin-mass interaction using a diamagnetic levitated magnetic resonance force sensor,"Axion-like particles (ALPs) are predicted to mediate exotic interactions
between spin and mass. We propose an ALP-searching experiment based on the
levitated micromechanical oscillator, which is one of the most sensitive
sensors for spin-mass forces at a short distance. The proposed experiment tests
the spin-mass resonant interaction between the polarized electron spins and a
diamagnetically levitated microsphere. By periodically flipping the electron
spins, the contamination from nonresonant background forces can be eliminated.
The levitated microoscillator can prospectively enhance the sensitivity by
nearly $10^3$ times over current experiments for ALPs with mass in the range 4
meV to 0.4 eV.",2010.14199v3
2020-12-07,Nuclear magnetic resonance spectroscopy of nonequilibrium steady states in quantum dots,"The optically induced polarization of localized electron spins in an ensemble
of quantum dots (QDs) dephases due to the interaction with the surrounding
nuclear spins. Despite this dephasing, the spins in the QDs can be controlled
to respond coherently by applying periodic laser pulses, leading to a revival
of the spin polarization before each pulse. This effect, known as spin mode
locking, strongly depends on an emerging selection of certain polarizations of
the nuclear spin bath which is driven to a steady state far from equilibrium.
We investigate the influence of the nuclear composition in In$_x$Ga$_{1-x}$As
QDs on this nonequilibrium behavior and demonstrate that nuclear magnetic
resonances (NMR) appear as very sharp minima in the magnetic field dependence
of the revival amplitude. This suggests a novel kind of NMR spectroscopy.",2012.03607v2
2021-03-17,Spin Resonance Amplitude and Frequency of a Single Atom on a Surface in a Vector Magnetic Field,"We used electron spin resonance (ESR) combined with scanning tunneling
microscopy (STM) to measure hydrogenated Ti (spin-1/2) atoms at low-symmetry
binding sites on MgO in vector magnetic fields. We found strongly anisotropic
g-values in all three spatial directions. Interestingly, the amplitude and
lineshape of the ESR signals are also strongly dependent on the angle of the
field. We conclude that the Ti spin is aligned along the magnetic field, while
the tip spin follows its strong magnetic anisotropy. Our results show the
interplay between the tip and surface spins in determining the ESR signals and
highlight the precision of ESR-STM to identify the single atom's spin states.",2103.09582v1
2021-05-24,Spin pumping of two-dimensional electron gas with Rashba and Dresselhaus spin-orbit interactions,"We theoretically consider spin pumping in a junction between a ferromagnetic
insulator (FI) and a two-dimensional electron gas (2DEG) in which the Rashba
and Dresselhaus spin-orbit interactions coexist. Using second-order
perturbation theory, we derive an increase in linewidth in the case of an
interfacial exchange coupling in a ferromagnetic resonance (FMR) experiment. We
clarify how the enhancement of Gilbert damping depends on the resonant
frequency and spin orientation of the FI. We show that this setup of an FMR
experiment can provide information on the spin texture of 2DEG at the Fermi
surface.",2105.11193v3
2021-05-26,Coupling spin defects in hexagonal boron nitride to monolithic bullseye cavities,"Color centers in hexagonal boron nitride (hBN) are becoming an increasingly
important building block for quantum photonic applications. Herein, we
demonstrate the efficient coupling of recently discovered spin defects in hBN
to purposely designed bullseye cavities. We show that the all monolithic hBN
cavity system exhibits an order of magnitude enhancement in the emission of the
coupled boron vacancy spin defects. In addition, by comparative finite
difference time domain modelling, we shed light on the emission dipole
orientation, which has not been experimentally demonstrated at this point.
Beyond that, the coupled spin system exhibits an enhanced contrast in optically
detected magnetic resonance readout and improved signal to noise ratio. Thus,
our experimental results supported by simulations, constitute a first step
towards integration of hBN spin defects with photonic resonators for a scalable
spin photon interface.",2105.12317v1
2022-01-05,Electrical readout microwave-free sensing with diamond,"While nitrogen-vacancy (NV-) centers have been extensively investigated in
the context of spin-based quantum technologies, the spin-state readout is
conventionally performed optically, which may limit miniaturization and
scalability. Here, we report photoelectric readout of ground-state
cross-relaxation features, which serves as a method for measuring electron spin
resonance spectra of nanoscale electronic environments and also for
microwave-free sensing. As a proof of concept, by systematically tuning NV
centers into resonance with the target electronic system, we extracted the
spectra for the P1 electronic spin bath in diamond. Such detection may enable
probing optically inactive defects and the dynamics of local spin environment.
We also demonstrate a magnetometer based on photoelectric detection of the
ground-state level anticrossings (GSLAC), which exhibits a favorable detection
efficiency as well as magnetic sensitivity. This approach may offer potential
solutions for determining spin densities and characterizing local environment.",2201.01801v1
2022-01-18,Terahertz electron paramagnetic resonance generalized spectroscopic ellipsometry: The magnetic response of the nitrogen defect in 4H-SiC,"We report on terahertz (THz) electron paramagnetic resonance generalized
spectroscopic ellipsometry (THz-EPR-GSE). Measurements of the field and
frequency dependencies of the magnetic response due to the spin transitions
associated with the nitrogen defect in 4H-SiC are shown as an example.
THz-EPR-GSE dispenses with the need of a cavity, permits independently scanning
field and frequency parameters, and does not require field or frequency
modulation. We investigate spin transitions of hexagonal ($h$) and cubic ($k$)
coordinated nitrogen including coupling with its nuclear spin (I=1), and we
propose a model approach for the magnetic susceptibility to account for the
spin transitions. From the THz-EPR-GSE measurements we can fully determine the
polarization properties of the spin transitions and we obtain $g$ and hyperfine
splitting parameters using magnetic field and frequency dependent Lorentzian
oscillator lineshape functions. We propose frequency-scanning THz-EPR-GSE as a
new and versatile method to study properties of spins in solid state materials.",2201.06695v1
2022-03-31,Fully tunable longitudinal spin-photon interactions in Si and Ge quantum dots,"Spin qubits in silicon and germanium quantum dots are promising platforms for
quantum computing, but entangling spin qubits over micrometer distances remains
a critical challenge. Current prototypical architectures maximize transversal
interactions between qubits and microwave resonators, where the spin state is
flipped by nearly resonant photons. However, these interactions cause
back-action on the qubit, that yield unavoidable residual qubit-qubit couplings
and significantly affect the gate fidelity. Strikingly, residual couplings
vanish when spin-photon interactions are longitudinal and photons couple to the
phase of the qubit. We show that large longitudinal interactions emerge
naturally in state-of-the-art hole spin qubits. These interactions are fully
tunable and can be parametrically modulated by external oscillating electric
fields. We propose realistic protocols to measure these interactions and to
implement fast and high-fidelity two-qubit entangling gates. These protocols
work also at high temperatures, paving the way towards the implementation of
large-scale quantum processors.",2203.17163v1
2022-07-21,Influence of nonuniform magnetization reorientation on spin-orbit torque measurements,"Measurements of spin-orbit torques in a ferromagnetic/nonmagnetic multilayer
are typically based on an assumption that the entire ferromagnetic layer
uniformly responds to the spin-orbit torque. This assumption breaks down when
the thickness of the ferromagnetic layer is comparable to the dynamic exchange
coupling length, which can be as short as a few nanometers in certain
measurement geometries. The nonuniform magnetization reorientation coupled with
nonuniform contribution of each magnetic sublayer to the magnetoresistance or
the Kerr effect may impact the accuracy in the extrapolation of spin-orbit
torque, particularly if a thick ferromagnetic layer is used. In this paper, we
use numerical models to investigate such an impact in three different
techniques: the magneto-optic-Kerr-effect method, the second-harmonic method
and the spin torque ferromagnetic resonance method. We show that the
second-harmonic and magneto-optic-Kerr-effect methods are prone to be
influenced by the nonuniform magnetization reorientation, while the spin torque
ferromagnetic resonance method is much less impacted.",2207.10349v1
2022-10-10,Strong coupling of a Gd$^{3+}$ multilevel spin system to an on-chip superconducting resonator,"We report the realization of a strong coupling between a Gd$^{3+}$ spin
ensemble hosted in a scheelite (CaWO$_4$) single crystal and the resonant mode
of a coplanar stripline superconducting cavity leading to a large separation of
spin-photon states of 146 MHz. The interaction is well described by the Dicke
model and the crystal-field Hamiltonian of the multilevel spin system. We
observe a change of the crystal-field parameters due to the presence of photons
in the cavity that generates a significant perturbation of the crystal ground
state. Using finite-element calculations, we numerically estimate the cavity
sensing volume as well as the average spin-photon coupling strength of
$g_0\approx$ 620 Hz. Lastly, the dynamics of the spin-cavity states are
explored via pulsed measurements by recording the cavity ring-down signal as a
function of pulse length and amplitude. The results indicate a potential method
to initialize this multilevel system in its ground state via an active cooling
process.",2210.05053v2
2023-06-21,Room temperature optically detected magnetic resonance of single spins in GaN,"Optically detected magnetic resonance (ODMR) is an efficient mechanism to
readout the spin of solid-state color centers at room temperature, thus
enabling spin-based quantum sensors of magnetic field, electric field, and
temperature with high sensitivity and broad commercial applicability. The
mechanism of room temperature ODMR is based on spin-dependent relaxation
between the optically excited states to the ground states, and thus it is an
intrinsic property of a defect center. In this work we report that two distinct
defect types exist in GaN based on their ODMR signatures. One group has small
negative ODMR based on a spin in a metastable state. The second group has large
(up to $\sim$30\%) positive ODMR contrast based on ground-state spin. Because
GaN is a mature semiconductor with well-developed electronic technologies
already developed, this defect platform is promising for integrated quantum
sensing applications.",2306.12337v1
2023-10-25,Two-qubit logic between distant spins in silicon,"Direct interactions between quantum particles naturally fall off with
distance. For future-proof qubit architectures, however, it is important to
avail of interaction mechanisms on different length scales. In this work, we
utilize a superconducting resonator to facilitate a coherent interaction
between two semiconductor spin qubits 250 $\mu$m apart. This separation is
several orders of magnitude larger than for the commonly employed direct
interaction mechanisms in this platform. We operate the system in a regime
where the resonator mediates a spin-spin coupling through virtual photons. We
report anti-phase oscillations of the populations of the two spins with
controllable frequency. The observations are consistent with iSWAP oscillations
and ten nanosecond entangling operations. These results hold promise for
scalable networks of spin qubit modules on a chip.",2310.16805v1
2023-11-14,Temperature Dependence of Spin Pumping in Ni81Fe19/NbN Bilayer Thin Films,"We present a comprehensive study of broadband spin pumping utilizing the
inverse spin Hall effect phenomena in bilayer samples comprising Ni81Fe19 (15
nm) and NbN (with NbN thickness varying from 20 nm to 140 nm), conducted over a
temperature and frequency range spanning from 300 K to 4 K and 2 GHz to 12 GHz,
respectively. Our investigations reveal a systematic shift in ferromagnetic
resonance fields, amplitude, and line widths as functions of both frequency and
temperature. Notably, we observed a temperature-dependent increase in the spin
Hall angle value, surpassing previously reported values. Furthermore, our
results demonstrate a pronounced temperature dependence in the inverse spin
Hall effect voltage, exhibiting a significant reduction below the Tc. This
reduction in inverse spin Hall effect voltage is accompanied by an increase in
the linewidth of the ferromagnetic resonance mode.",2311.08257v1
2024-02-02,Theory of acoustic-phonon involved exciton spin flip in perovskite semiconductors,"We present a theory of the acoustic phonon assisted spin-flip Raman
scattering (SFRS), or resonant photoluminescence with the spin flip of a
photoexcited exciton localized in a bulk cubic-phase perovskite semiconductor.
We consider the spin-flip transitions between the ground-state exciton spin
sublevels in external magnetic field B and discuss the variation of their
probability rate and polarization selection rules with the increase of B. The
transitions are treated as two-quantum processes with the virtual to and fro
transfer of the electron in the electron-hole pair between the bottom and first
excited conduction bands. The transfer occurs due to both the electron-hole
exchange interaction and the electron-phonon interaction. The theoretical
results allow one to distinguish the phonon assisted Raman scattering from (a)
the resonant Raman scattering with the combined spin flip of the localized
resident electron and hole and (b) the biexciton-mediated SFRS analyzed
previously.",2402.01556v1
2007-12-31,"Spin dynamics and spin freezing behavior in the two-dimensional antiferromagnet NiGa$_{2}$S$_{4}$ revealed by Ga-NMR, NQR and $μ$SR measurements","We have performed $^{69,71}$Ga nuclear magnetic resonance (NMR) and nuclear
quadrupole resonance (NQR) and muon spin rotation/resonance on the quasi
two-dimensional antiferromagnet (AFM) NiGa$_2$S$_4$, in order to investigate
its spin dynamics and magnetic state at low temperatures. Although there exists
only one crystallographic site for Ga in NiGa$_2$S$_4$, we found two distinct
Ga signals by NMR and NQR. The origin of the two Ga signals is not fully
understood, but possibly due to stacking faults along the c axis which induce
additional broad Ga NMR and NQR signals with different local symmetries. We
found the novel spin freezing occurring at $T_{\rm f}$, at which the specific
heat shows a maximum, from a clear divergent behavior of the nuclear
spin-lattice relaxation rate $1/T_{1}$ and nuclear spin-spin relaxation rate
$1/T_{2}$ measured by Ga-NQR as well as the muon spin relaxation rate
$\lambda$. The main sharp NQR peaks exhibit a stronger tendency of divergence,
compared with the weak broader spectral peaks, indicating that the spin
freezing is intrinsic in NiGa$_2$S$_4$. The behavior of these relaxation rates
strongly suggests that the Ni spin fluctuations slow down towards $T_{\rm f}$,
and the temperature range of the divergence is anomalously wider than that in a
conventional magnetic ordering. A broad structureless spectrum and
multi-component $T_1$ were observed below 2 K, indicating that a static
magnetic state with incommensurate magnetic correlations or inhomogeneously
distributed moments is realized at low temperatures. However, the wide
temperature region between 2 K and $T_{\rm f}$, where the NQR signal was not
observed, suggests that the Ni spins do not freeze immediately below $T_{\rm
f}$, but keep fluctuating down to 2 K with the MHz frequency range.",0801.0190v1
2007-01-04,Spin-modulated quasi-1D antiferromagnet LiCuVO_4,"We report on magnetic resonance studies within the magnetically ordered phase
of the quasi-1D antiferromagnet LiCuVO_4. Our studies reveal a spin
reorientational transition at a magnetic field H_c1 ~ 25 kOe applied within the
crystallographical (ab)-plane in addition to the recently observed one at H_c2
\~75 kOe [ M.G. Banks et al., cond-mat/0608554 (2006)]. Spectra of the
antiferromagnetic resonance (AFMR) along low-frequency branches can be
described in the frame of a macroscopic theory of exchange-rigid planar
magnetic structures. These data allow to obtain the anisotropy of the exchange
interaction together with a constant of the uniaxial anisotropy. Spectra of 7Li
nuclear magnetic resonance (NMR) show that, within the magnetically ordered
phase of LiCuVO_4 in the low-field range H < H_c1, a planar spiral spin
structure is realized with the spins lying in the (ab)-plane in agreement with
neutron scattering studies of B.J. Gibson et al. [Physica B Vol. 350, 253
(2004)]. Based on NMR spectra simulations, the transition at H_c1 can well be
described as a spin-flop transition, where the spin plane of the magnetically
ordered structure rotates to be perpendicular to the direction of the applied
magnetic field. For H > H_c2 ~ 75 kOe, our NMR spectra simulations show that
the magnetically ordered structure exhibits a modulation of the spin
projections along the direction of the applied magnetic field H.",0701083v1
2009-07-21,Normal-State Spin Dynamics and Temperature-Dependent Spin Resonance Energy in an Optimally Doped Iron Arsenide Superconductor,"The proximity of superconductivity and antiferromagnetism in the phase
diagram of iron arsenides, the apparently weak electron-phonon coupling and the
""resonance peak"" in the superconducting spin excitation spectrum have fostered
the hypothesis of magnetically mediated Cooper pairing. However, since most
theories of superconductivity are based on a pairing boson of sufficient
spectral weight in the normal state, detailed knowledge of the spin excitation
spectrum above the superconducting transition temperature Tc is required to
assess the viability of this hypothesis. Using inelastic neutron scattering we
have studied the spin excitations in optimally doped BaFe1.85Co0.15As2 (Tc = 25
K) over a wide range of temperatures and energies. We present the results in
absolute units and find that the normal state spectrum carries a weight
comparable to underdoped cuprates. In contrast to cuprates, however, the
spectrum agrees well with predictions of the theory of nearly antiferromagnetic
metals, without complications arising from a pseudogap or competing
incommensurate spin-modulated phases. We also show that the temperature
evolution of the resonance energy follows the superconducting energy gap, as
expected from conventional Fermi-liquid approaches. Our observations point to a
surprisingly simple theoretical description of the spin dynamics in the iron
arsenides and provide a solid foundation for models of magnetically mediated
superconductivity.",0907.3632v1
2012-07-07,Analytical description of spin-Rabi oscillation controlled electronic transitions rates between weakly coupled pairs of paramagnetic states with S=1/2,"We report on an analytical description of spin-dependent electronic
transition rates which are controlled by a radiation induced spin-Rabi
oscillation of weakly spin-exchange and spin-dipolar coupled paramagnetic
states (S=1/2). The oscillation components (the Fourier content) of the net
transition rates within spin-pair ensembles are derived for randomly
distributed spin resonances with account of a possible correlation between the
two distributions that correspond to the two individual pair partners. The
results presented here show that when electrically or optically detected Rabi
spectroscopy is conducted under an increasing driving field B_ 1, the Rabi
spectrum evolves from a single resonance peak at s=\Omega_R, where
\Omega_R=\gamma B_1 is the Rabi frequency (\gamma is the gyromagnetic ratio),
to three peaks at s= \Omega_R, s=2\Omega_R, and at low s<< \Omega_R. The
crossover between the two regimes takes place when \Omega_R exceeds the
expectation value \delta_0 of the difference of the Zeeman energies within the
pairs, which corresponds to the broadening of the magnetic resonance lines in
the presence of disorder caused by hyperfine field or distributions of Lande
g-factors. We capture this crossover by analytically calculating the shapes of
all three peaks at arbitrary relation between \Omega_R and \delta_0. When the
peaks are well-developed their widths are \Delta s ~ \delta_0^2/\Omega_R.",1207.1754v1
2016-08-29,Resonant optical spectroscopy and coherent control of Cr4+ spin ensembles in SiC and GaN,"Spins bound to point defects are increasingly viewed as an important resource
for solid-state implementations of quantum information technologies. In
particular, there is a growing interest in the identification of new classes of
defect spin that can be controlled optically. Here we demonstrate ensemble
optical spin polarization and optically detected magnetic resonance (ODMR) of
the S = 1 electronic ground state of chromium (Cr4+) impurities in silicon
carbide (SiC) and gallium nitride (GaN). Spin polarization is made possible by
the narrow optical linewidths of these ensembles (< 8.5 GHz), which are similar
in magnitude to the ground state zero-field spin splitting energies of the ions
at liquid helium temperatures. We therefore are able to optically resolve
individual spin sublevels within the ensembles at low magnetic fields using
resonant excitation from a cavity-stabilized, narrow-linewidth laser.
Additionally, these near-infrared emitters possess exceptionally weak phonon
sidebands, ensuring that > 73% of the overall optical emission is contained
with the defects zero-phonon lines. These characteristics make this
semiconductor-based, transition metal impurity system a promising target for
further study in the ongoing effort to integrate optically active quantum
states within common optoelectronic materials.",1608.08255v1
2018-10-13,Dynamics of spin-orbit-coupled cold atomic gases in a Floquet lattice with an impurity,"In this study, we have studied the quantum tunneling of a single
spin-orbit-coupled atom held in a periodically modulated optical lattice with
an impurity. At the pseudocollapse points of quasienergy bands, where the
dynamical localization takes place globally, two types of local second-order
tunneling processes appear beyond expectation between the two nearest-neighbor
sites of the impurity with the spin unchanged and with impurity site population
negligible all the time, when the impurity potential is far off-resonant with
the driving field. Though tunneling behaviors of the two types seem to be the
same, they are believed to involve two distinct mechanisms: one is related to
spin-independent process, while the other is to spin-dependent tunneling
process. The two types of second-order processes can be identified by means of
resonant tunneling with or without spin-flipping by tuning the impurity
potential to be in resonance with the driving field. In the Floquet picture,
the second-order processes are manifested as subtle and fine avoided crossings
of quasienergy spectrums near the pseudocollapse region. These results are
confirmed analytically on the basis of effective three-site model and
multiple-time-scale asymptotic perturbative method, and may be exploited for
engineering the spin-dependent quantum transport in realistic experiments.",1810.05854v1
2018-02-09,A T-shaped double quantum dot system as a Fano interferometer: interplay of coherence and correlation upon spin currents,"Based on Keldysh non-equilibrium Green function method, we have investigated
spin current production in a hybrid T-shaped device, consisting of a central
quantum dot connected to the leads and a side dot which only couples to the
central dot. The topology of this structure allows for quantum interference of
the different paths that go across the device, yielding Fano resonances in the
spin dependent transport properties. Correlation effects are taken into account
at the central dot and handled within a mean field approximation. Its interplay
with the Fano effect is analyzed in the strong coupling regime. Non-vanishing
spin currents are only obtained when the leads are ferromagnetic, the current
being strongly dependent on the relative orientation of the lead polarizations.
We calculate the conductance (spin and charge) by numerically differentiating
the current, and a rich structure is obtained as a manifestation of quantum
coherence and correlation effects. Increase of the Coulomb interaction produces
localization of states at the side dot, largely suppressing Fano resonances.
The interaction is also responsible for the negative values of the spin
conductance in some regions of the voltage near resonances, effect which is the
spin analog of the Esaki tunnel diode. We also analyze control of the currents
via gate voltages applied to the dots, possibility which is interesting for
practical operations.",1802.03439v1
2017-02-07,Resonant spin transfer torque nano-oscillators,"Spin transfer torque nano-oscillators are potential candidates for replacing
the traditional inductor based voltage controlled oscillators in modern
communication devices. Typical oscillator designs are based on trilayer
magnetic tunnel junctions which are disadvantaged by low power outputs and poor
conversion efficiencies. In this letter, we theoretically propose to use
resonant spin filtering in pentalayer magnetic tunnel junctions as a possible
route to alleviate these issues and present device designs geared toward a high
microwave output power and an efficient conversion of the d.c. input power. We
attribute these robust qualities to the resulting non-trivial spin current
profiles and the ultra high tunnel magnetoresistance, both arising from
resonant spin filtering. The device designs are based on the nonequilibrium
Green's function spin transport formalism self-consistently coupled with the
stochastic Landau-Lifshitz-Gilbert-Slonczewski's equation and the Poisson's
equation. We demonstrate that the proposed structures facilitate oscillator
designs featuring a large enhancement in microwave power of around $775\%$ and
an efficiency enhancement of over $1300\%$ in comparison with typical trilayer
designs. We also rationalize the optimum operating regions via an analysis of
the dynamic and static device resistances. This work sets stage for pentalyer
spin transfer torque nano-oscillator device designs that extenuate most of the
issues faced by the typical trilayer designs.",1702.01869v1
2021-10-04,Separation of Artifacts from Spin-Torque Ferromagnetic Resonance Measurements of Spin-Orbit Torque for the Low-Symmetry van der Waals Semi-Metal ZrTe$_\textbf{3}$,"We measure spin-orbit torque generated by exfoliated layers of the
low-symmetry semi-metal ZrTe$_3$ using the spin-torque ferromagnetic resonance
(ST-FMR) technique. When the ZrTe$_3$ has a thickness greater than about 10 nm,
artifacts due to spin pumping and/or resonant heating can cause the standard
ST-FMR analysis to overestimate the true magnitude of the torque efficiency by
as much as a factor of 30, and to indicate incorrectly that the spin-orbit
torque depends strongly on the ZrTe$_3$ layer thickness. Artifact-free
measurements can still be achieved over a substantial thickness range by the
method developed recently to detect ST-FMR signals in the Hall geometry as well
as the longitudinal geometry. ZrTe$_3$/Permalloy samples generate a
conventional in-plane anti-damping spin torque efficiency
$\xi_{||}^{\text{DL}}$ = 0.014 $\pm$ 0.004, and an unconventional in-plane
field-like torque efficiency $|\xi_{||}^{\text{FL}}|$ = 0.003 $\pm$ 0.001. The
out-of-plane anti-damping torque is negligible. We suggest that artifacts
similarly interfere with the standard ST-FMR analysis for other van der Waals
samples thicker than about 10 nm.",2110.01720v2
2019-07-17,Spin Measurements of NV Centers Coupled to a Photonic Crystal Cavity,"Nitrogen-vacancy (NV) centers feature outstanding properties like a spin
coherence time of up to one second as well as a level structure offering the
possibility to initialize, coherently manipulate and optically read-out the
spin degree of freedom of the ground state. However, only about three percent
of their photon emission are channeled into the zero phonon line (ZPL),
limiting both the rate of indistinguishable single photons and the
signal-to-noise ratio (SNR) of coherent spin-photon interfaces. We here report
on the enhancement of the SNR of the optical spin read-out achieved by tuning
the mode of a two-dimensional photonic crystal (PhC)cavity into resonance with
the NV-ZPL. PhC cavities are fabricated by focused ion beam (FIB) milling in
thin reactive ion (RIE) etched ultrapure single crystal diamond membranes
featuring modes with Q-factors of up to 8250 at mode volumes below one cubic
wavelength. NV centers are produced in the cavities in a controlled fashion by
a high resolution atomic force microscope (AFM) implantation technique. On
cavity resonance we observe a lifetime shortening from 9.0ns to 8.0ns as well
as an enhancement of the ZPL emission by almost one order of magnitude.
Although on resonance the collection efficiency of ZPL photons and the
spin-dependent fluorescence contrast are reduced, the SNR of the optical spin
read-out is almost tripled for the cavity-coupled NV centers.",1907.07602v1
2019-08-28,Tilting Ice Giants with a Spin-Orbit Resonance,"Giant collisions can account for Uranus's and Neptune's large obliquities,
yet generating two planets with widely different tilts and strikingly similar
spin rates is a low-probability event. Trapping into a secular spin-orbit
resonance, a coupling between spin and orbit precession frequencies, is a
promising alternative, as it can tilt the planet without altering its spin
period. We show with numerical integrations that if Uranus harbored a massive
circumplanetary disk at least three times the mass of its satellite system
while it was accreting its gaseous atmosphere, then its spin precession rate
would increase enough to resonate with its own orbit, potentially driving the
planet's obliquity to 70${^\circ}$. We find that the presence of a massive disk
moves the Laplace radius significantly outward from its classical value,
resulting in more of the disk contributing to the planet's pole precession.
Although we can generate tilts greater than 70${^\circ}$ only rarely and cannot
drive tilts beyond 90${^\circ}$, a subsequent collision with an object about
$0.5\,M_{\oplus}$ could tilt Uranus from 70${^\circ}$ to 98${^\circ}$.
Minimizing the masses and number of giant impactors from two or more to just
one increases the likelihood of producing Uranus's spin states by about an
order of magnitude. Neptune, by contrast, needs a less massive disk to explain
its 30${^\circ}$ tilt, eliminating the need for giant collisions altogether.",1908.10969v4
2021-07-20,"Magnetic topology in coupled binaries, spin-orbital resonances, and flares","We consider topological configurations of the magnetically coupled spinning
stellar binaries (e.g., merging neutron stars or interacting star-planet
systems). We discuss conditions when the stellar spins and the orbital motion
nearly `compensate' each other, leading to very {\it slow} overall winding of
the coupled magnetic fields; slowly winding configurations allow gradual
accumulation of magnetic energy, that is eventually released in a flare when
the instability threshold is reached. We find that this slow winding can be
global and/or local. We describe the topology of the relevant space
$\mathbb{F}=T^1S^2$ as the unit tangent bundle of the two-sphere and find
conditions for slowly winding configurations in terms of magnetic moments,
spins and orbital momentum. These conditions become ambiguous near the
topological bifurcation points; in certain cases they also depend on the
relative phases of the spin and orbital motions. In the case of merging
magnetized neutron stars, if one of the stars is a millisecond pulsar, spinning
at $\sim$ 10 msec, the global resonance $\omega_1+\omega_2= 2 \Omega$
(spin-plus beat is two times the orbital period) occurs approximately a second
before the merger; the total energy of the flare can be as large as $10\%$ of
the total magnetic energy, producing bursts of luminosity $\sim 10^{44}$ erg
s$^{-1}$. Higher order local resonances may have similar powers, since the
amount of involved magnetic flux tubes may be comparable to the total connected
flux.",2107.09702v3
2021-07-30,Coherent control of electron spin qubits in silicon using a global field,"Silicon spin qubits promise to leverage the extraordinary progress in silicon
nanoelectronic device fabrication over the past half century to deliver
large-scale quantum processors. Despite the scalability advantage of using
silicon technology, realising a quantum computer with the millions of qubits
required to run some of the most demanding quantum algorithms poses several
outstanding challenges, including how to control so many qubits simultaneously.
Recently, compact 3D microwave dielectric resonators were proposed as a way to
deliver the magnetic fields for spin qubit control across an entire quantum
chip using only a single microwave source. Although spin resonance of
individual electrons in the globally applied microwave field was demonstrated,
the spins were controlled incoherently. Here we report coherent Rabi
oscillations of single electron spin qubits in a planar SiMOS quantum dot
device using a global magnetic field generated off-chip. The observation of
coherent qubit control driven by a dielectric resonator establishes a credible
pathway to achieving large-scale control in a spin-based quantum computer.",2107.14622v2
2021-09-07,Exploring tidal obliquity variations with SMERCURY-T,"We introduce our new code, SMERCURY-T, which is based on existing codes
SMERCURY (Lissauer et al. 2012) and Mercury-T (Bolmont et al. 2015). The result
is a mixed-variable symplectic N-body integrator that can compute the orbital
and spin evolution of a planet within a multi-planet system under the influence
of tidal spin torques from its star. We validate our implementation by
comparing our experimental results to that of a secular model. As we
demonstrate in a series of experiments, SMERCURY-T allows for the study of
secular spin-orbit resonance crossings and captures for planets within complex
multi-planet systems. These processes can drive a planet's spin state to evolve
along vastly different pathways on its road toward tidal equilibrium, as tidal
spin torques dampen the planet's spin rate and evolve its obliquity.
Additionally, we show the results of a scenario that exemplifies the crossing
of a chaotic region that exists as the overlap of two spin-orbit resonances.
The test planet experiences violent and chaotic swings in its obliquity until
its eventual escape from resonance as it tidally evolves. All of these
processes are and have been important over the obliquity evolution of many
bodies within the Solar System and beyond, and have implications for planetary
climate and habitability. SMERCURY-T is a powerful and versatile tool that
allows for further study of these phenomena.",2109.03347v1
2022-04-12,Spinsim: a GPU optimized python package for simulating spin-half and spin-one quantum systems,"The Spinsim python package simulates spin-half and spin-one quantum
mechanical systems following a time dependent Shroedinger equation. It makes
use of numba.cuda, which is an LLVM (Low Level Virtual Machine) compiler for
Nvidia Cuda compatible systems using GPU parallelization. Along with other
optimizations, this allows for speed improvements from 3 to 4 orders of
magnitude while staying just as accurate, compared to industry standard
packages. It is available for installation on PyPI, and the source code is
available on github. The initial use-case for the Spinsim will be to simulate
quantum sensing-based ultracold atom experiments for the Monash University
School of Physics \& Astronomy spinor Bose-Einstein condensate (spinor BEC)
lab, but we anticipate it will be useful in simulating any range of spin-half
or spin-one quantum systems with time dependent Hamiltonians that cannot be
solved analytically. These appear in the fields of nuclear magnetic resonance
(NMR), nuclear quadrupole resonance (NQR) and magnetic resonance imaging (MRI)
experiments and quantum sensing, and with the spin-one systems of nitrogen
vacancy centres (NVCs), ultracold atoms, and BECs.",2204.05586v1
2022-07-04,Long-distance coupling of spin qubits via topological magnons,"We consider two distant spin qubits in quantum dots, both coupled to a
two-dimensional topological ferromagnet hosting chiral magnon edge states at
the boundary. The chiral magnon is used to mediate entanglement between the
spin qubits, realizing a fundamental building block of scalable quantum
computing architectures: a long-distance two-qubit gate. Previous proposals for
long-distance coupling with magnons involved off-resonant coupling, where the
detuning of the spin-qubit frequency from the magnonic band edge provides
protection against spontaneous relaxation. The topological magnon mode, on the
other hand, lies in-between two magnonic bands far away from any bulk magnon
resonances, facilitating strong and highly tuneable coupling between the two
spin qubits. Even though the coupling between the qubit and the chiral magnon
is resonant for a wide range of qubit splittings, we find that the
magnon-induced qubit relaxation is vastly suppressed if the coupling between
the qubit and the ferromagnet is antiferromagnetic. A fast and high-fidelity
long-distance coupling protocol is presented capable of achieving spin-qubit
entanglement over micrometer distances with $1\,$MHz gate speed and up to
$99.9\%$ fidelities. The resulting spin-qubit entanglement may be used as a
probe for the long-sought detection of topological edge magnons.",2207.01264v1
2023-12-21,Electric dipole spin resonance in single and two electron quantum dot defined in two-dimensional electron gas at the SrTiO$_3$/LaAlO$_3$ interface,"We investigate the energy spectrum of a single and two electron quantum dot
(QD) embedded in two dimensional electron gas at the interface between
SrTiO$_3$ and LaAlO$_3$, in the presence of the external magnetic field. For
this purpose the three band model of $3d$-electrons defined on the square
lattice of Ti ions was utilized. We demonstrate that, for the weak parabolic
confinement potential, the low energy spectrum is sufficiently well described
by the effective Hamiltonian reduced to the one $d_{xy}$ orbital with the
spin-orbit interaction originating from the coupling to the $d_{xz}$, $d_{yz}$
bands. This is not the case for stronger confinement where contribution of the
states related to the $d_{xz/yz}$ orbital is relevant. Based on the time
depended calculations we discuss in details the manipulation of the electron
spin in QD by external AC voltages, in the context of the electric dipole spin
resonance. The allowed and forbidden transitions are discussed in details with
respect to the parity selection rule. Our calculations show that for a single
electron QD the spin-flip in the ground-state has a character of a Rabi
resonance while for two electrons the singlet-triplet transition is forbidden
by the parity symmetry. For the two electrons QD, we demonstrate that the
spin-flip transition can still be accomplished via a second-order, two-photon
process that has a two-state Rabi character for low AC field amplitude. The
violation of the parity symmetry on the spin-flip transitions is also analyzed.",2312.13862v2
2019-12-05,Ion Scale Electromagnetic Waves in the Inner Heliosphere,"Understanding the physical processes in the solar wind and corona which
actively contribute to heating, acceleration, and dissipation is a primary
objective of NASA's Parker Solar Probe (PSP) mission. Observations of coherent
electromagnetic waves at ion scales suggests that linear cyclotron resonance
and non-linear processes are dynamically relevant in the inner heliosphere. A
wavelet-based statistical study of coherent waves in the first perihelion
encounter of PSP demonstrates the presence of transverse electromagnetic waves
at ion resonant scales which are observed in 30-50\% of radial field intervals.
Average wave amplitudes of approximately 4 nT are measured, while the mean
duration of wave events is of order 20 seconds; however long duration wave
events can exist without interruption on hour-long timescales. Though ion scale
waves are preferentially observed during intervals with a radial mean magnetic
field, we show that measurement constraints, associated with single spacecraft
sampling of quasi-parallel waves superposed with anisotropic turbulence, render
the measured quasi-parallel ion-wave spectrum unobservable when the mean
magnetic field is oblique to the solar wind flow; these results imply that the
occurrence of coherent ion-scale waves is not limited to a radial field
configuration. The lack of strong radial scaling of characteristic wave
amplitudes and duration suggests that the waves are generated {\em{in-situ}}
through plasma instabilities. Additionally, observations of proton distribution
functions indicate that temperature anisotropy may drive the observed ion-scale
waves.",1912.02361v1
2004-06-03,Phase diagram of the half-filled two-dimensional SU(N) Hubbard-Heisenberg model: a quantum Monte Carlo study,"We investigate the phase diagram of the half-filled SU(N) Hubbard-Heisenberg
model with hopping t, exchange J and Hubbard U, on a square lattice. In the
large-N limit, and as a function of decreasing values of t/J, the model shows a
transition from a d-density wave state to a spin dimerized insulator. A similar
behavior is observed at N=6 whereas at N=2 a spin density wave insulating
ground state is stabilized. The N=4 model, has a d-density wave ground state at
large values of t/J which as a function of decreasing values of t/J becomes
unstable to an insulating state with no apparent lattice and spin broken
symmetries. In this state, the staggered spin-spin correlations decay as a
power-law,resulting in gapless spin excitations at q = (pi,pi). Furthermore,
low lying spin modes with small spectral weight are apparent around the wave
vectors q = (0,pi) and q = (pi,0). This gapless spin liquid state is equally
found in the SU(4) Heisenberg model in the self-adjoint antisymmetric
representation. An interpretation of this state in terms of a pi-flux phase is
offered. Our results stem from projective (T=0) quantum Monte-Carlo simulations
on lattice sizes ranging up to 24 X 24.",0406074v1
1995-08-04,The spin of the nucleon in its rest system,"The spin dependent structure functions, g$_{1p}$ of the proton and g$_{1n}$
of the neutron, calculated in the nucleon rest frame using a relativistic quark
model wave function, are compared with recent experiments.",9508228v1
2009-04-10,Template banks to search for compact binaries with spinning components in gravitational wave data,"Gravitational waves from coalescing compact binaries are one of the most
promising sources for detectors such as LIGO, Virgo and GEO600. If the
components of the binary posess significant angular momentum (spin), as is
likely to be the case if one component is a black hole, spin-induced precession
of a binary's orbital plane causes modulation of the gravitational-wave
amplitude and phase. If the templates used in a matched-filter search do not
accurately model these effects then the sensitivity, and hence the detection
rate, will be reduced. We investigate the ability of several search pipelines
to detect gravitational waves from compact binaries with spin. We use the
post-Newtonian approximation to model the inspiral phase of the signal and
construct two new template banks using the phenomenological waveforms of
Buonanno, Chen and Vallisneri. We compare the performance of these template
banks to that of banks constructed using the stationary phase approximation to
the non-spinning post-Newtonian inspiral waveform currently used by LIGO and
Virgo in the search for compact binary coalescence. We find that, at the same
false alarm rate, a search pipeline using phenomenological templates is no more
effective than a pipeline which uses non-spinning templates. We recommend the
continued use of the non-spinning stationary phase template bank until the
false alarm rate associated with templates which include spin effects can be
substantially reduced.",0904.1715v1
2019-05-06,Direct Visualization of Spatial inhomogeneity of Spin Stripes Order in La1.72Sr0.28NiO4,"In several strongly correlated electron systems, defects, charge and local
lattice distortions are found to show complex inhomogeneous spatial
distributions. There is growing evidence that such inhomogeneity plays a
fundamental role in unique functionality of quantum complex materials.
La1.72Sr0.28NiO4 is a prototypical strongly correlated material showing spin
striped order associated with lattice and charge modulations. In this work we
present the spatial distribution of the spin organization by applying micro
X-ray diffraction to La1.72Sr0.28NiO4, mapping the spin-density-wave order
below the 120K onset temperature. We find that the spin-density-wave order
shows the formation of nanoscale puddles with large spatial fluctuations. The
nano-puddle density changes on the microscopic scale forming a multiscale phase
separation extending from nanoscale to micron scale with scale-free
distribution. Indeed spin-density-wave striped puddles are disconnected by
spatial regions with different stripe orientation or negligible
spin-density-wave order. The present work highlights the complex nanoscale
phase separation of spin stripes in nickelate perovskites and opens the
question of the energetics at domain interfaces",1905.02124v2
2017-03-14,Waveform measurement of charge- and spin-density wave packets in a Tomonaga-Luttinger liquid,"In contrast to a free electron system, a Tomonaga-Luttinger (TL) liquid in a
one dimensional (1D) electron system hosts charge and spin excitations as
independent entities. When an electron wave packet is injected into a TL
liquid, it transforms into wave packets carrying either charge or spin that
propagate at different group velocities and move away from each other. This
process, known as spin-charge separation, is the hallmark of TL physics. While
the existence of these TL eigenmodes has been identified in momentum- or
frequency-resolved measurements, their waveforms, which are a direct
manifestation of 1D electron dynamics, have been long awaited to be measured.
In this study, we present a time domain measurement for the
spin-charge-separation process in an asymmetric chiral TL liquid comprising
quantum Hall (QH) edge channels. We measure the waveforms of both charge and
spin excitations by combining a spin filter with a time-resolved charge
detector. Spatial separation of charge- and spin-wave packets over a distance
exceeding 200 um was confirmed. In addition, we found that the 1D electron
dynamics can be controlled by tuning the electric environment. These
experimental results provide fundamental information about non-equilibrium
phenomena in actual 1D electron systems.",1703.04833v1
2019-07-17,Neutron Scattering Study of Magnetic Anisotropy in a Tetragonal Antiferromagnet Bi$_2$CuO$_4$,"We present a comprehensive study of magnon excitations in the tetragonal
easy-plane anti-ferromagnet Bi$_2$CuO$_4$ using inelastic neutron scattering
and spin wave analyses. The nature of low energy magnons, and hence the
anisotropy in this material, has been controversial. We show unambiguously that
the low energy magnon spectrum consists of a gapped and a gapless mode, which
we attribute to out-of-plane and in-plane spin fluctuations, respectively. We
modelled the observed magnon spectrum using linear spin wave analysis of a
minimal anisotropic spin model motivated by the lattice symmetry. By studying
the magnetic field dependence of the (1, 0, 0) Bragg peak intensity and the
in-plane magnon intensity, we observed a spin-flop transition in the $ab$ plane
at $\sim0.4$~T which directly indicates the existence of a small in-plane
anisotropy that is classically forbidden. It is only by taking into account
magnon zero-point fluctuations beyond the linear spin wave approximation, we
could explain this in-plane anisotropy and its magnitude, the latter of which
is deduced from critical field of the spin-flop transition. The microscopic
origins of the observed anisotropic interactions are also discussed. We found
that our data is inconsistent with a large Dzyaloshinskii-Moriya interaction,
which suggests a potential departure of Bi$_2$CuO$_4$ from the conventional
theories of magnetic anisotropy for other cuprates.",1907.07784v2
2016-04-27,Slow waves in locally resonant metamaterials line defect waveguides,"In the past decades, many efforts have been devoted to the temporal
manipulation of waves, especially focusing on slowing down their propagation.
In electromagnetism, from microwave to optics, as well as in acoustics or for
elastic waves, slow wave propagation indeed largely benefits both applied and
fundamental physics. It is for instance essential in analog signal computing
through the design of components such as delay lines and buffers, and it is one
of the prerequisite for increased wave/matter interactions. Despite the
interest of a broad community, researches have mostly been conducted in optics
along with the development of wavelength scaled structured composite media,
that appear promising candidates for compact slow light components. Yet their
minimum structural scale prevents them from being transposed to lower
frequencies where wavelengths range from sub-millimeter to meters. In this
article, we propose to overcome this limitation thanks to the deep
sub-wavelength scale of locally resonant metamaterials. In our approach,
implemented here in the microwave regime, we show that introducing coupled
resonant defects in such composite media allows the creation of deep
sub-wavelength waveguides. We experimentally demonstrate that waves, while
propagating in such waveguides, exhibit largely reduced group velocities. We
qualitatively explain the mechanism underlying this slow wave propagation and
first experimentally demonstrate, then numerically verify, how it can be taken
advantage of to tune the velocity, achieving group indices ng as high as 227
over relatively large bandwidths. We conclude by highlighting the three
beneficial consequences of our line defect slow wave waveguides in locally
resonant metamaterials: the deep sub-wavelength scale, the very large group
indices and the fact that slow wave propagation does not occur at the expense
of drastic bandwidth reductions.",1604.08117v2
2003-05-30,The Secular Evolution of the Primordial Kuiper Belt,"A model that computes the secular evolution of a gravitating disk-planet
system is developed. The disk is treated as a set of gravitating rings, with
the rings'/planets' time-evolution governed by the classical Laplace-Lagrange
solution for secular evolution but modified to account for the disk's finite
thickness h. This system's Lagrange planetary equations yield a particular
class of spiral wave solutions, usually denoted as apsidal density waves and
nodal bending waves. There are two varieties of apsidal waves:long waves and
short waves. Planets typically launch long density waves at the disk's nearer
edge or else at a secular resonance in the disk, and these waves ultimately
reflect downstream at a more distant disk edge or else at a Q-barrier in the
disk, whereupon they return as short density waves. Planets also launch nodal
bending waves, and these have the property that they can stall in the disk,
that is, their group velocity plummets to zero upon approaching a disk region
too thick to support the continued propagation of bending waves. The rings
model is used to compute the secular evolution of a Kuiper Belt having a
variety of masses, and it is shown that the early massive Belt was very
susceptible to the propagation of low-amplitude apsidal and nodal waves
launched by the giant planets.",0305602v1
2006-01-23,Small divisor problem in the theory of three-dimensional water gravity waves,"We consider doubly-periodic travelling waves at the surface of an infinitely
deep perfect fluid, only subjected to gravity $g$ and resulting from the
nonlinear interaction of two simply periodic travelling waves making an angle
$2\theta $ between them. \newline Denoting by $\mu =gL/c^{2}$ the dimensionless
bifurcation parameter ($L$ is the wave length along the direction of the
travelling wave and $c$ is the velocity of the wave), bifurcation occurs for
$\mu =\cos \theta$. For non-resonant cases, we first give a large family of
formal three-dimensional gravity travelling waves, in the form of an expansion
in powers of the amplitudes of two basic travelling waves. ""Diamond waves"" are
a particular case of such waves, when they are symmetric with respect to the
direction of propagation.\newline \emph{The main object of the paper is the
proof of existence} of such symmetric waves having the above mentioned
asymptotic expansion. Due to the \emph{occurence of small divisors}, the main
difficulty is the inversion of the linearized operator at a non trivial point,
for applying the Nash Moser theorem. This operator is the sum of a second order
differentiation along a certain direction, and an integro-differential operator
of first order, both depending periodically of coordinates. It is shown that
for almost all angles $\theta $, the 3-dimensional travelling waves bifurcate
for a set of ""good"" values of the bifurcation parameter having asymptotically a
full measure near the bifurcation curve in the parameter plane $(\theta ,\mu
).$",0601551v1
2017-07-17,The First Ionization Potential Effect from the Ponderomotive Force: On the Polarization and Coronal Origin of the Alfven Waves,"We investigate in more detail the origin of chromospheric Alfven waves that
give rise to the separation of ions and neutrals, the First Ionization
Potential Effect (FIP), through the action of the ponderomotive force. In open
field regions, we model the dependence of fractionation on the plasma upflow
velocity through the chromosphere for both shear (or planar) and torsional
Alfven waves of photospheric origin. These differ mainly through their
parametric coupling to slow mode waves. Shear Alfven waves appear to reproduce
observed fractionations for a wider range of model parameters, and present less
of a ""fine-tuning"" problem than do torsional waves. In closed field regions, we
study the fractionations produced by Alfven waves with photospheric and coronal
origins. Waves with a coronal origin, at or close to resonance with the coronal
loop, offer a significantly better match to observed abundances than do
photospheric waves, with shear and torsional waves in such a case giving
essentially indistinguishable fractionations. Such coronal waves are likely the
result of a nanoflare coronal heating mechanism, that as well as heating
coronal plasmas releases Alfven waves that can travel down to loop footpoints
and cause FIP fractionation through the ponderomotive force as they reflect
from the chromosphere back into the corona.",1707.05378v1
2020-02-21,Quasi-periodic traveling gravity-capillary waves,"We present a numerical study of spatially quasi-periodic traveling waves on
the surface of an ideal fluid of infinite depth. This is a generalization of
the classic Wilton ripple problem to the case when the ratio of wave numbers
satisfying the dispersion relation is irrational. We propose a conformal
mapping formulation of the water wave equations that employs a quasi-periodic
variant of the Hilbert transform to compute the normal velocity of the fluid
from its velocity potential on the free surface. We develop a Fourier
pseudo-spectral discretization of the traveling water wave equations in which
one-dimensional quasi-periodic functions are represented by two-dimensional
periodic functions on the torus. This leads to an overdetermined nonlinear
least squares problem that we solve using a variant of the Levenberg-Marquardt
method. We investigate various properties of quasi-periodic traveling waves,
including Fourier resonances, time evolution in conformal space on the torus,
asymmetric wave crests, capillary wave patterns that change from one gravity
wave trough to the next without repeating, and the dependence of wave speed and
surface tension on the amplitude parameters that describe a two-parameter
family of waves.",2002.09487v2
2022-07-17,Phase convergence and crest enhancement of modulated wave trains,"The Akhmediev breather (AB) solution of the nonlinear Schr$\""{o}$dinger
equation (NLSE) shows that the maximum crest height of modulated wave trains
reaches triple the initial amplitude as a consequence of nonlinear long-term
evolution. Several fully nonlinear numerical studies have indicated that the
amplification can exceed 3, but its physical mechanism has not been clarified.
This study shows that spectral broadening, bound-wave production, and phase
convergence are essential to crest enhancement beyond the AB solution. The
free-wave spectrum of modulated wave trains broadens owing to nonlinear
quasi-resonant interaction. This enhances bound-wave production at high
wavenumbers. The phases of all the wave components nearly coincide at peak
modulation and enhance amplification. We find that the phase convergence
observed in linear-focusing waves can also occur due to nonlinear wave
evolution. These findings are obtained by numerically investigating the
modulated wave trains using the higher-order spectral method (HOSM) up to the
fifth order, which allows investigations of nonlinearity and spectral bandwidth
beyond the NLSE framework. Moreover, we confirm the crest enhancement through a
tank experiment wherein waves are generated in the transition region from
non-breaking to breaking. Owing to strong nonlinearity, the maximum crest
height observed in the tank begins to exceed the HOSM prediction at an initial
wave steepness of 0.10.",2207.08176v1
2023-03-02,Internal gravity waves in stratified flows with and without vortical modes,"The comprehension of stratified flows is important for geophysical and
astrophysical applications. The Weak Wave Turbulence theory aims to provide a
statistical description of internal gravity waves propagating in the bulk of
such flows. However, internal gravity waves are usually perturbed by other
structures present in stratified flow, namely the shear modes and the vortical
modes. In order to check whether a weak internal gravity wave turbulence regime
can occur, we perform direct numerical simulations of stratified turbulence
without shear modes, and with or without vortical modes at various Froude and
buoyancy Reynolds numbers. We observe that removing vortical modes naturally
helps to have a better overall balance between poloidal kinetic energy,
involved in internal gravity waves, and potential energy. However, conversion
between kinetic energy and potential energy does not necessarily show
fluctuations around zero in our simulations, as we would expect for a system of
weak waves. A spatiotemporal analysis reveals that removing vortical modes
helps to concentrate the energy around the wave frequency, but it is not enough
to observe a weak wave turbulence regime. Yet, we observe that internal gravity
waves whose frequency are large compared to the eddy turnover time are present,
and we also find evidences for slow internal gravity waves interacting by
Triadic Resonance Instabilities in our strongly stratified flows simulations.
Finally, we propose conditions that should be fulfilled in order to observe a
weak internal gravity waves turbulence regime in real flows.",2303.01570v3
2024-03-22,Generation of narrow beams of super high-energy gamma quanta in the resonant inverse Compton-effect in the field of a strong x-ray wave,"The article presents a theoretical study of Oleinik resonances in the process
of scattering a gamma quantum by an ultrarelativistic electron in the field of
a strong electromagnetic wave. It is shown that under resonant conditions, the
scattering channels of the reaction effectively split into two first-order
processes according to a fine structure constant such as the external
field-stimulated Compton effect. And the annihilation channel of the reaction
effectively decays into direct and reverse the external field-stimulated
Breit-Wheeler processes. The significant dependence of the resonant energy of
final particles and resonant cross sections on the outgoing angles of the final
gamma quantum, the number of absorbed and emitted photons of the wave, as well
as the characteristic quantum parameters of the problem is shown. These quantum
parameters are determined by the ratio of the initial particle energies to the
characteristic energies of the Compton effect and the Breit-Wheeler process. An
unambiguous relationship between the outgoing angles of final electrons and
gamma quanta has been obtained, which qualitatively distinguishes the resonant
process from the non-resonant one. The cases when the energy of the initial
electrons significantly exceeds the energy of the initial gamma quanta have
been studied. The conditions under which the energy of high-energy initial
electrons is converted into the energy of final gamma quanta are obtained. At
the same time, the resonant differential cross-section of such a process
significantly (by several orders of magnitude) exceeds the corresponding
non-resonant cross-section. This theoretical study predicts a number of new
physical effects that may explain the high-energy fluxes of gamma quanta born
near neutron stars and magnetars.",2403.15519v2
2020-03-11,Phase mixing and wave heating in a complex coronal plasma,"Aims. We investigate the formation of small scales and the dissipation of MHD
wave energy through non-linear interactions of counter-propagating, phase-mixed
Alfvenic waves in a complex magnetic field. Methods. We conducted fully 3-D,
non-ideal MHD simulations of transverse waves in complex magnetic fields.
Continuous wave drivers were imposed on the foot points of magnetic field lines
and the system was evolved for several Alfven travel times. Phase-mixed waves
were allowed to reflect off the upper boundary and the interactions between the
resultant counter-streaming wave packets were analysed. Results. The complex
nature of the background magnetic field encourages the development of phase
mixing, leading to a growth in currents and vorticities. Counter-propagating
phase-mixed waves induce a cascade of energy to small scales and result in more
efficient energy dissipation. This effect is enhanced in simulations with more
complex magnetic fields. High-frequency drivers excite localised field line
resonances and produce efficient wave heating. However, this relies on the
formation of large amplitude oscillations on resonant field lines. Drivers with
smaller frequencies than the fundamental frequencies of field lines are not
able to excite resonances and thus do not inject sufficient Poynting flux to
power coronal heating. Even in the case of high-frequency oscillations, the
rate of dissipation is likely too slow to balance coronal energy losses, even
within the quiet Sun. Conclusions. For the generalised phase-mixing presented
here, complex background field structures enhance the rate of wave energy
dissipation. However, it remains difficult for realistic wave drivers to inject
sufficient Poynting flux to heat the corona. Indeed, significant heating only
occurs in cases which exhibit amplitudes that are much larger than those
currently observed in the solar atmosphere.",2003.05226v1
2004-10-19,MHD tidal waves on a spinning magnetic compact star,"In an X-ray binary system, the companion star feeds the compact neutron star
with plasma materials via accretions. The spinning neutron star is likely
covered with a thin ""magnetized ocean"" and may support {\it magnetohydrodynamic
(MHD) tidal waves}. While modulating the thermal properties of the ocean, MHD
tidal waves periodically shake the base of the stellar magnetosphere that traps
energetic particles, including radiating relativistic electrons. For a radio
pulsar, MHD tidal waves in the stellar surface layer may modulate radio
emission processes and leave indelible signatures on timescales different from
the spin period. Accretion activities are capable of exciting these waves but
may also obstruct or obscure their detections meanwhile. Under fortuitous
conditions, MHD tidal waves might be detectable and offer valuable means to
probe properties of the underlying neutron star. Similar situations may also
occur for a cataclysmic variable -- an accretion binary system that contains a
rotating magnetic white dwarf. This Letter presents the theory for MHD tidal
waves in the magnetized ocean of a rotating degenerate star and emphasizes
their potential diagnostics in X-ray and radio emissions.",0410428v1
2002-06-04,Delocalization and spin-wave dynamics in ferromagnetic chains with long-range correlated random exchange,"We study the one-dimensional quantum Heisenberg ferromagnet with exchange
couplings exhibiting long-range correlated disorder with power spectrum
proportional to $1/k^{\alpha}$, where $k$ is the wave-vector of the modulations
on the random coupling landscape. By using renormalization group, integration
of the equations of motion and exact diagonalization, we compute the spin-wave
localization length and the mean-square displacement of the wave-packet. We
find that, associated with the emergence of extended spin-waves in the
low-energy region for $\alpha > 1$, the wave-packet mean-square displacement
changes from a long-time super-diffusive behavior for $\alpha <1$ to a
long-time ballistic behavior for $\alpha > 1$. At the vicinity of $\alpha =1$,
the mobility edge separating the extended and localized phases is shown to
scale with the degree of correlation as $E_c\propto (\alpha -1)^{1/3}$.",0206038v1
1999-05-15,Electromagnetic radiation of the travelling spin wave propagating in an antiferromagnetic plate. Exact solution,"The exact solution of radiation problem of a spin wave travelling in an
antiferromagnetic (AFM) plate was found. The spin wave with in-plane
oscillations of antiferromagnetism vector was considered. In this case the
magnetization vector is oscillating being perpendicular to the AFM plate and
depends on time and plane coordinates as travelling wave does. This model
allows to obtain exact analytical expression for Hertzian vector and,
consequently, the retarded potentials and field strengths as well. It is shown
that expressions obtained describe Cherenkov radiation caused by the travelling
wave. The radiated electromagnetic wave is the TEM type if a phase velocity
exceeds the speed of light. Otherwise electric and magnetic field values
exponentially decrease in the direction normal to the plate. The energy losses
were evaluated also.",9905036v1
2009-12-03,Partial-wave contributions to pairing in nuclei,"We present a detailed study of partial-wave contributions of nuclear forces
to pairing in nuclei. For T=1, J=0 pairing, partial waves beyond the standard
1S0 channel play an interesting role for the pair formation in nuclei. The
additional contributions are dominated by the repulsive 3P1 partial wave. Their
effects, and generally spin-triplet nuclear forces between paired nucleons, are
influenced by the interplay of spin-orbit partners. We explore the impact of
including partial waves beyond the 1S0 channel on neutron-neutron pairing gaps
in semi-magic isotopic chains. In addition, we show that nuclear forces favor
T=1, J=0 over T=0, J=1 pairing, except in low-j orbitals. This is in contrast
to the free-space motivation that suggests the formation of deuteron-like T=0
pairs in N=Z nuclei. The suppression of T=0 pairing is because the 3S1 strength
is distributed on spin-orbit partners and because of the effects of the
repulsive 1P1 channel and of D waves.",0912.0697v1
2012-08-13,Ground state of spin-1 Bose-Einstein condensates with spin-orbit coupling in a Zeeman field,"We systematically investigate the weakly trapped spin-1 Bose-Einstein
condensates with spin-orbit coupling in an external Zeeman field. We find that
the mean-field ground state favors either a magnetized standing wave phase or
plane wave phase when the strength of Zeeman field is below a critical value
related to the strength of spin-orbit coupling. Zeeman field can induce the
phase transition between standing wave and plane wave phases, and we determine
the phase boundary analytically and numerically. The magnetization of these two
phases responds to the external magnetic field in a very unique manner, the
linear Zeeman effect magnetizes the standing wave phase along the direction of
the magnetic field, but the quadratic one demagnetizes the plane wave phase.
When the strength of Zeeman field surpasses the critical value, the system is
completely polarized to a ferromagnetic state or polar state with zero
momentum.",1208.2514v1
2013-08-23,Impact of eddy currents on the dispersion relation of surface spin waves in thin conducting magnetic films,"We propose a rigorous solution to a long-standing problem of the impact of
eddy currents on the dispersion relation of surface spin waves propagating in
thin conducting magnetic films. Our results confirm the prediction of the
Almeida-Mill's exchange-free theory that the inclusion of the eddy current
contribution results in a deviation of the dispersion curve for the fundamental
mode from the Damon-Eshbach law and a substantial linewidth broadening in a
large wave vector range. We show that the decrease in the spin wave frequency
is due to an increase in the in-plane component of the dynamic magnetic field
within the conducting film. The decrease in the frequency is accompanied by a
drastic change in the asymmetry of the modal profiles for the waves. This
effect is not observable in magneto-insulating films and therefore it is
unambiguously attributed to eddy currents that appear in conducting films only.
We also show that the wave vector range in which eddy currents affect the
dispersion curve is strongly correlated with the value of the film
conductivity. This result holds for conducting films with the thickness 10-100
nm, which are considered promising for future magnonic and spintronic
applications.",1308.5040v1
2016-06-09,Snell's Law for Spin Waves,"We report the experimental observation of Snell's law for magneto-static spin
waves in thin ferromagnetic Permalloy films by imaging incident, refracted and
reflected waves. We use a thickness step as the interface between two media
with different dispersion relation. Since the dispersion relation for
magneto-static waves in thin ferromagnetic films is anisotropic, deviations
from the isotropic Snell's law known in optics are observed for incidence
angles larger than 25\textdegree{} with respect to the interface normal between
the two magnetic media. Furthermore, we can show that the thickness step
modifies the wavelength and the amplitude of the incident waves. Our findings
open up a new way of spin wave steering for magnonic applications.",1606.02895v1
2016-10-27,Observation of Self-Cavitating Envelope Dispersive Shock Waves in Yttrium Iron Garnet Thin Films,"The formation and properties of envelope dispersive shock wave (DSW)
excitations from repulsive nonlinear waves in a magnetic film are studied.
Experiments involve the excitation of a spin-wave step pulse in a low-loss
magnetic Y$_3$Fe$_5$O$_{12}$ thin film strip, in which the spin-wave amplitude
increases rapidly, realizing the canonical Riemann problem of shock theory.
Under certain conditions, the envelope of the spin-wave pulse evolves into a
DSW that consists of an expanding train of nonlinear oscillations with
amplitudes increasing from front to back, terminated by a black soliton. The
onset of DSW self-cavitation, indicated by a point of zero power and a
concomitant 180 phase jump, is observed for sufficiently large steps,
indicative of the bidirectional dispersive hydrodynamic nature of the DSW. The
experimental observations are interpreted with theory and simulations of the
nonlinear Schr\""odinger equation.",1610.08846v3
2022-11-21,Spin Hall effect of radiofrequency waves in magnetized plasmas,"In inhomogeneous media, electromagnetic-wave rays deviate from the
trajectories predicted by the leading-order geometrical optics. This effect,
called the spin Hall effect of light, is typically neglected in ray-tracing
codes used for modeling waves in plasmas. Here, we demonstrate that the spin
Hall effect can be significant for radiofrequency waves in toroidal magnetized
plasmas whose parameters are in the ballpark of those used in fusion
experiments. For example, an electron-cyclotron wave beam can deviate by as
large as ten wavelengths ($\sim 0.1\,\text{m}$) relative to the lowest-order
ray trajectory in the poloidal direction. We calculate this displacement using
gauge-invariant ray equations of extended geometrical optics, and we also
compare our theoretical predictions with full-wave simulations.",2211.11705v5
2022-12-19,Confined phase singularities reveal the spin-to-orbital angular momentum conversion of sound waves,"We identify an acoustic process in which the conversion of angular momentum
between its spin and orbital form takes place. The interaction between an
evanescent wave propagating at the interface of two immiscible fluids and an
isolated droplet is considered. The elliptical motion of the fluid supporting
the incident wave is associated with a simple state of spin angular momentum, a
quantity recently introduced for acoustic waves in the literature. We
experimentally observe that this field predominantly forces a directional wave
transport circling the droplet's interior, revealing the existence of confined
phase singularities. The circulation of the phase, around a singular point, is
characteristic of angular momentum in its orbital form, thereby demonstrating
the conversion mechanism. The numerical and experimental observations presented
in this work have implications for the fundamental understanding of the angular
momentum of acoustic waves, and for applications such as particle manipulation
with radiation forces or torques, acoustic sensing and imaging.",2212.09439v2
2023-01-03,"Caustic spin wave beams in soft, thin films: properties and classification","In the context of wave propagation, caustics are usually defined as the
envelope of a finite-extent wavefront; folds and cusps in a caustic result in
enhanced wave amplitudes. Here, we tackle a related phenomenon, namely the
existence of well-defined beams originating solely from the geometric
properties of the corresponding dispersion relation. This directional emission,
termed caustic beam, is enabled by a stationary group velocity direction, and
has been observed first in the case of phonons. We propose an overview of this
""focusing"" effect in the context of spin waves excited in soft, thin
ferromagnetic films. Based on an analytical dispersion relation, we provide
tools for a systematic survey of caustic spin wave beams. Our theoretical
approach is validated by time-resolved microscopy experiments using the
magneto-optical Kerr effect. Then, we identify two cases of particular interest
both from fundamental and applicative perspectives. Indeed, both of them enable
broadband excitations (in terms of wave vectors) to result in narrowband beams
of low divergence.",2301.01220v1
2021-12-30,Topological materials for full-vector elastic waves,"Elastic wave manipulation is important in a wide variety of scales in
applications including information processing in tiny elastic devices and noise
control in big solid structures. The recent emergence of topological materials
opens a new avenue toward modulating elastic waves in solids. However, because
of the full-vector feature, and the complicated couplings of the longitudinal
and transverse components of elastic waves, manipulating elastic waves is
generally difficult, compared with manipulating acoustic waves (scalar waves)
and electromagnetic waves (vectorial waves but transverse only). Up to date,
topological materials, including insulators and semimetals, have been realized
for acoustic and electromagnetic waves. Although topological materials of
elastic waves have also been reported, the topological edge modes observed all
lie on the domain wall. A natural question can be asked: whether there exists
an elastic metamaterial with the topological edge modes on its own boundary
only? Here, we report a 3D metal-printed bilayer metamaterial, insulating
topologically the elastic waves. By introducing the chiral interlayer
couplings, the spin-orbit couplings for elastic waves are induced, which give
rise to nontrivial topological properties. The helical edge states with the
vortex feature are demonstrated on the boundary of the single topological
phase. We further show a heterostructure of the metamaterial, which exhibits
tunable edge transport. Our work may have potential in devices based on elastic
waves in solids.",2201.04950v1
2006-11-21,Exceptional and non-exceptional contributions to the radiative πdecay,"We have studied the spin-one resonance dominated form factors governing the
radiative decay of the \pi, within the framework of resonance chiral theory. We
obtain predictions for their value at zero momentum transfer and also a
description of their q^2 dependence.",0611282v1
2004-01-12,Giant dipole resonance with exact treatment of thermal fluctuations,"The shape fluctuations due to thermal effects in the giant dipole resonance
(GDR) observables are calculated using the exact free energies evaluated at
fixed spin and temperature. The results obtained are compared with Landau
theory calculations done by parameterizing the free energy. The Landau theory
is found to be insufficient when the shell effects are dominating.",0401020v1
1997-04-07,A Greenberger-Horne-Zeilinger experiment for mixed states,"This paper shows how the Greenberger-Horne-Zeilinger experiment, which
demonstrates the nonlocal nature of quantum mechanics, can be performed using
nuclear magnetic resonance on spins in molecules at finite temperature. The use
of nuclear magnetic resonance techniques allows the experiment to uncover the
nonlocality not just of special GHZ states, but of arbitrary three particle
states.",9704013v1
2000-03-18,A Magnetic Resonance Force Microscopy Quantum Computer with Tellurium Donors in Silicon,"We propose a magnetic resonance force microscopy (MRFM)-based nuclear spin
quantum computer using tellurium impurities in silicon. This approach to
quantum computing combines the well-developed silicon technology with expected
advances in MRFM.",0003076v1
2010-02-28,Deflagration with quantum and dipolar effects in a model of a molecular magnet,"Combination of the thermal effet in magnetic deflagration with resonance spin
tunneling controlled by the dipole-dipole interaction in molecular magnets
leads to the increase of the deflagration speed in the dipolar window near
tunneling resonances.",1003.0208v1
2012-08-05,Bottomonium and Bottomonium-like States and Decays at Belle,"Recent results from the Belle experiment are presented. We report the results
of the first observation of P-wave spin-singlet Bottomonium states, observation
of two charged Bottomonium-like resonances and the first observation of the
radiative transition hb(1P)\rightarrow{\eta}b(1S){\gamma} at the Y(5S)
resonance region.",1208.1050v1
2012-10-01,A Quantum Mechanical Review of Magnetic Resonance Imaging,"In this paper, we review the quantum mechanics of magnetic resonance imaging
(MRI). We traverse its hierarchy of scales from the spin and orbital angular
momentum of subatomic particles to the ensemble magnetization of tissue. And we
review a number of modalities used in the assessment of acute ischemic stroke
and traumatic brain injury.",1210.0946v1
2015-05-18,Magnetic Resonance Lithography with Nanometer Resolution,"We propose an approach for super-resolution optical lithography which is
based on the inverse of magnetic resonance imaging (MRI). The technique uses
atomic coherence in an ensemble of spin systems whose final state population
can be optically detected. In principle, our method is capable of producing
arbitrary one and two dimensional high-resolution patterns with high contrast.",1505.04496v1
2012-09-28,Feshbach resonance: a one dimensional example,"We present a simple one-dimensional example of a spin 1/2 particle submitted
to a delta-type potential which interacs differently with the two components of
the wavefunction and to an external magnetic field. It has two coupled
channels, admits a closed solution and features the Feshbach resonance
phenomenon by proper tunning of the magnetic field.",1209.6441v1
1997-06-27,High-field Electron Spin Resonance of Cu_{1-x}Zn_{x}GeO_{3},"High-Field Electron Spin Resonance measurements were made on powder samples
of Cu_{1-x}Zn_{x}GeO_{3} (x=0.00, 0.01, 0.02, 0.03 and 0.05) at different
frequencies (95, 110, 190, 220, 330 and 440 GHz) at low temperatures. The
spectra of the doped samples show resonances whose positions are dependent on
Zn concentration, frequency and temperature. The analysis of intensity
variation of these lines with temperature allows us to identify them as
originating in transitions within states situated inside the Spin Peierls gap.
A qualitative explanation of the details of the spectra is possible if we
assume that these states in the gap are associated with ""loose"" spins created
near the Zn impurities, as recently theoreticaly predicted. A new phenomenon of
quenching of the ESR signal across the Dimerized to Incommensurate
phase-boundary is observed.",9706286v1
1998-06-28,Magnetic Resonance of the Intrinsic Defects of the Spin-Peierls Magnet CuGeO3,"ESR of the pure monocrystals of CuGeO3 is studied in the frequency range 9-75
GHz and in the temperature interval 1.2-25 K. The splitting of the ESR line
into several spectral components is observed below 5 K, in the temperature
range where the magnetic susceptibility is suppressed by the spin-Peierls
dimerization. The analysis of the magnetic resonance signals allows one to
separate the signals of the S=1/2- and S=1 defects of the spin-Peierls phase.
The value of g-factor of these signals is close to that of the Cu-ion. The
additional line of the magnetic resonance is characterized by an anomalous
value of the g-factor and by the threshold-like increase of the microwave
susceptibility when the microwave power is increasing. The ESR signals are
supposingly attributed to two types of the planar magnetic defects, arising at
the boundaries of the domains of the spin-Peierls state with the different
values of the phase of the dimerization.",9806347v2
2000-02-18,Coupling to spin fluctuations from conductivity scattering rates,"A recent analysis of optical conductivity data which has provided strong
evidence for coupling of the charge carriers to the 41 meV spin resonance, seen
in the superconducting state of optimally doped Y123, is extended to other
systems. We find that the corresponding spin resonance is considerably broader
in Tl2201 and Y124 than it is in Bi2212. On the other hand, in overdoped Tl2201
with T_c = 23 K no resonance forms. A more specific interpretation of the
optical data in terms of a spin fluctuation exchange mechanism of
superconductivity gives an underlying effective spectral density which is
strongly temperature dependent and which contains important feedback effects
that further stabilize superconductivity as the temperature is reduced.",0002283v2
2000-10-04,The Resonance Peak in Sr$_2$RuO$_4$: Signature of Spin Triplet Pairing,"We study the dynamical spin susceptibility, $\chi({\bf q}, \omega)$, in the
normal and superconducting state of Sr$_2$RuO$_4$. In the normal state, we find
a peak in the vicinity of ${\bf Q}_i\simeq (0.72\pi,0.72\pi)$ in agreement with
recent inelastic neutron scattering (INS) experiments. We predict that for spin
triplet pairing in the superconducting state a {\it resonance peak} appears in
the out-of-plane component of $\chi$, but is absent in the in-plane component.
In contrast, no resonance peak is expected for spin singlet pairing.",0010067v2
2004-02-11,Dispersion Anomalies in Cuprate Superconductors,"We argue that the shape of the dispersion along the nodal and antinodal
directions in the cuprates can be understood as a consequence of the
interaction of the electrons with collective spin excitations. In the normal
state, the dispersion displays a crossover at an energy where the decay into
spin fluctuations becomes relevant. In the superconducting state, the antinodal
dispersion is strongly affected by the spin resonance and displays an S-shape
whose magnitude scales with the resonance intensity. For nodal fermions,
relevant spin excitations do not have resonance behavior, rather they are
better characterized as a gapped continuum. As a consequence, the S-shape
becomes a kink, and superconductivity does not affect the dispersion as
strongly. Finally, we note that optical phonons typically lead to a temperature
independent S-shape, in disagreement with the observed dispersion.",0402304v1
2004-11-24,Effect of spin-orbit coupling on zero-conductance resonances in asymmetrically coupled one-dimensional rings,"The influence of Rashba spin-orbit coupling on zero conductance resonances
appearing in one dimensional ring asymmetrically coupled to two leads is
investigated. For this purpose, the transmission function of the corresponding
one-electron scattering problem is derived analytically and analyzed in the
complex energy plane with focus on the zero-pole structure characteristic of
transmission (anti)resonances. The lifting of real conductance zeros due to
spin-orbit coupling in the asymmetric Aharonov-Casher (AC) ring is related to
the breaking of spin reversal symmetry in analogy to the time-reversal symmetry
breaking in the asymmetric Aharonov-Bohm (AB) ring.",0411620v2
2006-01-31,Spin-lattice interaction in the quasi one-dimensional helimagnet LiCu_2O_2,"The field dependence of the electron spin resonance in a helimagnet,
LiCu_2O_2, was investigated for the first time. In the paramagnetic state a
broad resonance line was observed corresponding to a g-factor of 2.3. In the
critical regime around the paramagnetic to helimagnetic phase transition the
resonance broadens and shifts to higher frequencies. A narrow signal is
recovered at low temperature, corresponding to a spin gap of 1.5 meV in zero
field. A comprehensive model of the magnons is presented, using exchange
parameters from neutron scattering (T. Masuda et al,
  Phys. Rev. B 72, 014405), and the spin anisotropy determined here. The role
of the quantum fluctuations is discussed.",0601701v1
2006-10-02,g-Factor Tuning and Manipulation of Spins by an Electric Current,"We investigate the Zeeman splitting of two-dimensional electrons in an
asymmetric silicon quantum well, by electron-spin-resonance (ESR) experiments.
Applying a small dc current we observe a shift in the resonance field due to
the additional current-induced Bychkov-Rashba (BR) type of spin-orbit (SO)
field. This finding demonstrates SO coupling in the most straightforward way:
in the presence of a transverse electric field the drift velocity of the
carriers imposes an effective SO magnetic field. This effect allows selective
tuning of the g-factor by an applied dc current. In addition, we show that an
ac current may be used to induce spin resonance very efficiently.",0610046v1
1996-04-09,Effects Of The Quantity $σ_{TS}$ On The Spin Structure Functions Of Nucleons In The Resonance Region,"In this paper, we investigate the effects of the quantity $\sigma_{TS}$ on
the spin-structure functions of nucleons in the resonance region. The Schwinger
sum rule for the spin structure function $g_2(x,Q^2)$ at the real photon limit
is derived for the nucleon treated as a composite system, and it provides a
crucial constraint on the longitudinal transition operator which has not been
treated consistently in the literature. The longitudinal amplitude $S_{\frac
12}$ is evaluated in the quark model with the transition operator that
generates the Schwinger sum rule. The numerical results of the quantity
$\sigma_{TS}$ are presented for both spin structure functions $g_1(x,Q^2)$ and
$g_2(x,Q^2)$ in the resonance region. Our results show that this quantity
  plays an important role in the low $Q^2$ region, which can be tested in the
future experiments at CEBAF.",9604274v1
2001-11-21,Measurement of parity-nonconserving rotation of neutron spin in the 0.734-eV p-wave resonance of $^{139}La$,"The parity nonconserving spin rotation of neutrons in the 0.734-eV p-wave
resonance of $^{139}La$ was measured with the neutron transmission method. Two
optically polarized $^3He$ cells were used before and behind a a 5-cm long
$^{139}La$ target as a polarizer and an analyzer of neutron spin. The rotation
angle was carefully measured by flipping the direction of $^3He$ polarization
in the polarizer in sequence. The peak-to-peak value of the spin rotation was
found to be $ (7.4 \pm 1.1) \times 10^{-3} $ rad/cm which was consistent with
the previous experiments. But the result was statisticallly improved. The s-p
mixing model gives the weak matrix element as $xW = (1.71 \pm 0.25)$ meV. The
value agrees well with the one deduced from the parity-nonconserving
longitudinal asymmetry in the same resonance.",0111018v1
2007-05-24,Separation of Bell states,"The four Bell states can be represented by separable coherent states which
are products of individual non-hermitian spin operators. In the absence of
interactions, the non-hermitian states are predicted to form a new quantum
state of spin magnitude 1/sqrt(2) rather than 1/2. Properties of these states
show that an isolated spin is a resonance state with zero net angular momentum,
consistent with a point particle. In addition, the Bell states are shown to
take on the identical mathematical form when the two spins are bound (local) or
unbound (non-local). The bound Bell states are resonances between four states.
When the separate, they do so from only one of its resonance states and their
ensemble average defines the unbound Bell states. The bound and unbound Bell
states have the same mathematical form due to the persistence of the
rotationally invariance of sigma(1)dot sigma(2).",0705.3657v5
2009-08-21,High precision beam momentum determination in a synchrotron using a spin resonance method,"In order to measure the mass of the eta meson with high accuracy using the
d+p -> 3He+eta reaction, the momentum of the circulating deuteron beam in the
Cooler Synchrotron COSY of the Forschungszentrum Juelich has to be determined
with unprecedented precision. This has been achieved by studying the spin
dynamics of the polarized deuteron beam. By depolarizing the beam through the
use of an artificially induced spin resonance, it was possible to evaluate its
momentum p with a precision of dp/p < 10-4 for a momentum of roughly 3 GeV/c.
Different possible sources of error in the application of the spin resonance
method are discussed in detail and its possible use during a standard
experiment is considered.",0908.3103v2
2010-04-06,Electron spin resonance in S=1/2 antiferromagnets at high temperature,"We study the electron spin resonance (ESR) of low-dimensional spin systems at
high temperature, and test the Kubo-Tomita theory of exchange narrowing. In
finite-size systems (molecular magnets), we found a double-peak resonance which
strongly differs from the usual Lorentzian. For infinite systems, we have
predictions for the linewidth and lineshape as a function of the anisotropy
strength. For this, we have used an interpolation between a non-perturbative
calculation of the memory function at short times (exact diagonalization) and
the hydrodynamic spin-diffusion at long times. We show that the
Dzyaloshinskii-Moriya anisotropies generally induce a much larger linewidth
than the exchange anisotropies in two dimensions, contrary to the
one-dimensional case.",1004.0839v1
2010-08-19,Decay of Rabi oscillations induced by magnetic dipole interactions in diluted paramagnetic solids,"Decay of Rabi oscillations of equivalent spins diluted in diamagnetic solid
matrix and coupled by magnetic dipole interactions is studied. It is shown that
these interactions result in random shifts of spin transient nutation
frequencies and thus lead to the decay of the transient signal. Averaging over
random spatial distribution of spins within the solid and over their spectral
positions within magnetic resonance line, we obtain analytical expressions for
the decay of Rabi oscillations. The rate of the decay in the case when the
half-width of magnetic resonance line exceeds Rabi frequency is found to depend
on the intensity of resonant microwave field and on the spin concentration. The
results are compared with the literature data for E1' centers in glassy silica
and [AlO4] centers in quartz.",1008.3337v1
2010-09-27,"Multicolored quantum dimer models, resonating valence-bond states, color visons, and the triangular-lattice t_2g spin-orbital system","The spin-orbital model for triply degenerate t_2g electrons on a triangular
lattice has been shown to be dominated by dimers: the phase diagram contains
both strongly resonating, compound spin-orbital dimer states and quasi-static,
spin-singlet valence-bond (VB) states. To elucidate the nature of the true
ground state in these different regimes, the model is mapped to a number of
quantum dimer models (QDMs), each of which has three dimer colors. The generic
multicolored QDM, illustrated for the two- and three-color cases, possesses a
topological color structure, ""color vison"" excitations, and broad regions of
resonating VB phases. The specific models are analyzed to gain further insight
into the likely ground states in the superexchange and direct-exchange limits
of the electronic Hamiltonian, and suggest a strong tendency towards VB order
in all cases.",1009.5140v1
2010-11-26,Modes of magnetic resonance of S=1 dimer chain compound NTENP,"The spin dynamics of a quasi one dimensional $S=1$ bond alternating spin-gap
antiferromagnet Ni(C$_9$H$_{24}$N$_4$)NO$_2$(ClO$_4$) (abbreviated as NTENP) is
studied by means of electron spin resonance (ESR) technique. Five modes of ESR
transitions are observed and identified: transitions between singlet ground
state and excited triplet states, three modes of transitions between spin
sublevels of collective triplet states and antiferromagnetic resonance
absorption in the field-induced antiferromagnetically ordered phase.
Singlet-triplet and intra-triplet modes demonstrate a doublet structure which
is due to two maxima in the density of magnon states in the low-frequency
range. A joint analysis of the observed spectra and other experimental results
allows to test the applicability of the fermionic and bosonic models. We
conclude that the fermionic approach is more appropriate for the particular
case of NTENP.",1011.5742v1
2011-05-11,Spin-Orbit Coupled Fermi Gases across a Feshbach Resonance,"In this letter we study both ground state properties and the superfluid
transition temperature of a spin-1/2 Fermi gas across a Feshbach resonance with
a synthetic spin-orbit coupling, using mean-field theory and exact solution of
two-body problem. We show that a strong spin-orbit coupling can significantly
enhance the pairing gap for 1/(k_F a_s)<=0 due to increased density-of-state.
Strong spin-orbit coupling also significantly enhances the superfluid
transition temperature when 1/(k_F a_s)<=0, while suppresses it slightly when
1/(k_F a_s)>0. The universal interaction energy and pair size at resonance are
also discussed.",1105.2250v3
2011-08-23,Resonant X-Ray Diffraction Study of Strongly Spin-Orbit-Coupled Mott Insulator CaIrO3,"We performed resonant x-ray diffraction experiments at the $L$ absorption
edges for the post-perovskite-type compound CaIrO$_{3}$ with $(t_{2g})^5$
electronic configuration. By observing the magnetic signals, we could clearly
see that the magnetic structure was a striped order with an antiferromagnetic
moment along the c-axis and that the wavefunction of a $t_{2g}$ hole is
strongly spin-orbit entangled, the $J_{\rm eff} =1/2$ state. The observed spin
arrangement is consistent with theoretical work predicting a unique
superexchange interaction in the $J_{\rm eff} =1/2$ state and points to the
universal importance of the spin-orbit coupling in Ir oxides, irrespective of
the local coordination and lattice topology. We also propose that the
non-magnetic resonant scattering is a powerful tool for unraveling an orbital
state even in a metallic iridate.",1108.4523v1
2011-10-25,Dynamic nuclear spin polarization in resonant laser spectroscopy of a quantum dot,"Resonant optical excitation of lowest-energy excitonic transitions in
self-assembled quantum dots lead to nuclear spin polarization that is
qualitatively different from the well known optical orientation phenomena. By
carrying out a comprehensive set of experiments, we demonstrate that nuclear
spin polarization manifests itself in quantum dots subjected to finite external
magnetic field as locking of the higher energy Zeeman transition to the driving
laser field, as well as the avoidance of the resonance condition for the lower
energy Zeeman branch. We interpret our findings on the basis of dynamic nuclear
spin polarization originating from non-collinear hyperfine interaction and find
an excellent agreement between the experimental results and the theoretical
model.",1110.5524v1
2012-07-12,Medium effects close to s- and p-wave Feshbach resonances in atomic Fermi gases,"Many-body effects may influence properties, such as scattering parameters,
nature of pairing, etc., close to a Feshbach resonance in the fermion BEC-BCS
crossover problem. We study effects such as these using a tractable
crossing-symmetric approach. This method allow us to include quantum
fluctuations, such as, density, current, spin, spin-current and the
higher-order fluctuations in a self-consistent fashion. The underlying fermion
interaction is reflected in the ""driving"" term. We perform calculations here on
both Bose-Einstein condensate (BEC) and BCS sides, and taking the driving term
to be finite range, and of arbitrary strength. These are related to two-body
singlet and triplet scattering parameters, and can be connected with
experimental s- and p-wave Feshbach resonances. We include the $\ell=0$ density
and spin fluctuations, as well as $\ell=1$ current and spin-current
fluctuations. We calculate renormalized scattering amplitudes, pairing
amplitudes, nature of pairing, etc., on both the BEC and BCS sides. We then
compare our results qualitatively with experiments.",1207.2856v1
2012-08-02,Generating entanglement with low Q-factor microcavities,"We propose a method of generating entanglement using single photons and
electron spins in the regime of resonance scattering. The technique involves
matching the spontaneous emission rate of the spin dipole transition in bulk
dielectric to the modified rate of spontaneous emission of the dipole coupled
to the fundamental mode of an optical microcavity. We call this regime
resonance scattering where interference between the input photons and those
scattered by the resonantly coupled dipole transition result in a reflectivity
of zero. The contrast between this and the unit reflectivity when the cavity is
empty allow us to perform a non demolition measurement of the spin and to non
deterministically generate entanglement between photons and spins. The chief
advantage of working in the regime of resonance scattering is that the required
cavity quality factors are orders of magnitude lower than is required for
strong coupling, or Purcell enhancement. This makes engineering a suitable
cavity much easier particularly in materials such as diamond where etching high
quality factor cavities remains a significant challenge.",1208.0455v1
2012-12-17,Heavy-quark spin symmetry for charmed and strange baryon resonances,"We study charmed and strange baryon resonances that are generated dynamically
by a unitary baryon-meson coupled-channels model which incorporates heavy-quark
spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa
chiral Lagrangian to SU(8) spin-flavor symmetry plus a suitable symmetry
breaking. The model generates resonances with negative parity from the s-wave
interaction of pseudoscalar and vector mesons with 1/2+ and 3/2+ baryons in all
the isospin, spin, and strange sectors with one, two, and three charm units.
Some of our results can be identified with experimental data from several
facilities, such as the CLEO, Belle, or BaBar Collaborations, as well as with
other theoretical models, whereas others do not have a straightforward
identification and require the compilation of more data and also a refinement
of the model.",1212.3943v2
2013-01-30,Influence of MgO tunnel barrier thickness on spin-transfer ferromagnetic resonance and torque in magnetic tunnel junctions,"Spin-transfer ferromagnetic resonance (ST-FMR) in symmetric magnetic tunnel
junctions (MTJs) with a varied thickness of the MgO tunnel barrier (0.75 nm <
$t_{MgO}$ < 1.05 nm) is studied using the spin-torque diode effect. The
application of an RF current into nanosized MTJs generates a DC mixing voltage
across the device when the frequency is in resonance with the resistance
oscillations arising from the spin transfer torque. Magnetization precession in
the free and reference layers of the MTJs is analyzed by comparing ST-FMR
signals with macrospin and micromagnetic simulations. From ST-FMR spectra at
different DC bias voltage, the in-plane and perpendicular torkances are
derived. The experiments and free-electron model calculations show that the
absolute torque values are independent of tunnel barrier thickness. The
influence of coupling between the free and reference layer of the MTJs on the
ST-FMR signals and the derived torkances are discussed.",1301.7186v1
2013-02-04,Many-body \textit{T}-matrix theory of a strongly interacting spin-orbit coupled Fermi gas: Momentum-resolved radio-frequency spectroscopy and fermionic pairing,"Interacting Fermi gases with spin-orbit coupling are responsible for many
intriguing phenomena such as topological superfluids and Majorana fermions.
Here we characterize theoretically fermionic pairing in a strongly interacting
spin-orbit coupled Fermi gas, by using momentum-resolved radio-frequency
spectroscopy. We develop a strong-coupling $T$-matrix theory and present a
phase diagram near the unitary resonance limit. A smooth transition from atomic
to molecular responses in the momentum-resolved spectroscopy is predicted, with
a clear signature of anisotropic pairing at and below resonance. Our prediction
with many-body pairing can be directly tested in a spin-orbit coupled Fermi gas
of $^{40}$K or $^{6}$Li atoms near broad Feshbach resonances.",1302.0559v2
2013-07-03,ESR of the quasi-two-dimensional antiferromagnet with a triangular lattice CuCrO2,"Using electron-spin-resonance (ESR) technique we investigate the magnetic
structure of CuCrO2, quasi-two-dimensional antiferromagnet with weakly
distorted triangular lattice. Resonance frequencies and the excitation
conditions in CuCrO2 at low temperatures are well described in the frame of
cycloidal spin structure, defined by two susceptibilities parallel and
perpendicular to the spin plane and by a biaxial crystal-field anisotropy. In
agreement with the calculations, the character of the eigenmodes changes
drastically at the spin-flop transition. The splitting of the observed modes
can be well attributed to the resonances from different domains. The domain
structure in CuCrO2 can be controlled by annealing of the sample in magnetic
field.",1307.0955v2
2014-07-23,Resolving single molecule structures with nitrogen-vacancy centers in diamond,"We present two-dimensional nuclear magnetic resonance spectroscopy protocols
based on nitrogen-vacancy (NV) centers in diamond as efficient quantum sensors
of protein structure. Continuous microwave driving fields are used to achieve
Hartmann-Hahn resonances between NV spin sensor and proximate nuclei for
selective control of nuclear spins and measurement of their polarization. Our
protocols take advantage of the strong coupling between the NV sensor and the
nuclei, thus facilitating coherence control of nuclear spins and relax the
requirement of nuclear spin polarization. We dramatically reduce the
experimental effort by employing a singular value thresholding matrix
completion algorithm from signal processing to regain the resolution of protein
structure based on sub-sampled data from NV based single molecule nuclear
magnetic resonance spectroscopy. As an illustration, we demonstrate the power
of this approach by identifying the nitrogen-Hydrogen interaction peak in an
Alanine spectrum based on merely 5% of the sample data.",1407.6262v1
2015-02-09,Collective nature of spin excitations in superconducting cuprates probed by resonant inelastic x-ray scattering,"We used resonant inelastic x-ray scattering (RIXS) with and without analysis
of the scattered photon polarization, to study dispersive spin excitations in
the high temperature superconductor YBa2Cu3O6+x over a wide range of doping
levels (0.1 < x < 1). The excitation profiles were carefully monitored as the
incident photon energy was detuned from the resonant condition, and the spin
excitation energy was found to be independent of detuning for all x. These
findings demonstrate that the largest fraction of the spin-flip RIXS profiles
in doped cuprates arises from magnetic collective modes, rather than from
incoherent particle-hole excitations as recently suggested theoretically
[Benjamin et al. Phys. Rev. Lett. 112, 247002(2014)]. Implications for the
theoretical description of the electron system in the cuprates are discussed.",1502.02583v1
2015-02-28,Interaction of Strain and Nuclear Spins in Silicon: Quadrupolar Effects on Ionized Donors,"The nuclear spins of ionized donors in silicon have become an interesting
quantum resource due to their very long coherence times. Their perfect
isolation, however, comes at a price, since the absence of the donor electron
makes the nuclear spin difficult to control. We demonstrate that the
quadrupolar interaction allows us to effectively tune the nuclear magnetic
resonance of ionized arsenic donors in silicon via strain and determine the two
nonzero elements of the S tensor linking strain and electric field gradients in
this material to $S_{11}=1.5\times10^{22}$ V/m$^2$ and $S_{44}=6\times 10^{22}$
V/m$^2$. We find a stronger benefit of dynamical decoupling on the coherence
properties of transitions subject to first-order quadrupole shifts than on
those subject to only second-order shifts and discuss applications of
quadrupole physics including mechanical driving of magnetic resonance, cooling
of mechanical resonators, and strain-mediated spin coupling.",1503.00133v2
2015-04-06,Spin Pumping in Electrodynamically Coupled Magnon-Photon Systems,"We use electrical detection, in combination with microwave transmission, to
investigate both resonant and non-resonant magnon-photon coupling at room
temperature. Spin pumping in a dynamically coupled magnon-photon system is
found to be distinctly different from previous experiments. Characteristic
coupling features such as modes anti-crossing, line width evolution, peculiar
line shape, and resonance broadening are systematically measured and
consistently analyzed by a theoretical model set on the foundation of classical
electrodynamic coupling. Our experimental and theoretical approach pave the way
for pursuing microwave coherent manipulation of pure spin current via the
combination of spin pumping and magnon-photon coupling.",1504.01335v1
2015-05-05,Spin pumping from a ferromagnet into a hopping insulator: the role of resonant absorption of magnons,"Motivated by recent experiments on spin pumping from a ferromagnet into
organic materials in which the charge transport is due to hopping, we study
theoretically the generation and propagation of spin current in a hopping
insulator. Unlike metals, the spin polarization at the boundary with
ferromagnet is created as a result of magnon absorption within pairs of
localized states and it spreads following the current-currying resistor network
(although the charge current is absent). We consider a classic resonant
mechanism of the ac absorption in insulators and adapt it to the absorption of
magnons. A strong enhancement of pumping efficiency is predicted when the
Zeeman splitting of the localized states in external magnetic field is equal to
the frequency of ferromagnetic resonance. Under this condition the absorption
of a magnon takes place within individual sites.",1505.01211v1
2016-01-11,Light Quark Spin Symmetry in $Z_b$ Resonances?,"It is argued that the recent Belle data, consistent with no activity in the
spectrum of the $B^* \bar B + B \bar B^*$ pairs at the mass of the $Z_b(10650)$
resonance, imply that the part of the interaction between heavy mesons that
depends on the total spin of the light quark and antiquark is strongly
suppressed. In particular this part appears to be significantly weaker than can
be inferred from pion exchange. If confirmed by future more detailed data, the
symmetry with respect to the light quark spins, in combination with the heavy
quark spin symmetry, would imply existence of four additional $I^G=1^-$
resonances at the thresholds for heavy meson-antimeson pairs.",1601.02540v1
2017-12-16,High pressure electron spin resonance of the endohedral fullerene $^{15}\mathrm{N@C}_{60}$,"We measure the electron spin resonance spectrum of the endohedral fullerene
molecule $^{15}\mathrm{N@C}_{60}$ at pressures ranging from atmospheric
pressure to 0.25 GPa, and find that the hyperfine coupling increases linearly
with pressure. We present a model based on van der Waals interactions, which
accounts for this increase via compression of the fullerene cage and consequent
admixture of orbitals with a larger hyperfine coupling. Combining this model
with theoretical estimates of the bulk modulus, we predict the pressure shift
and compare it to our experimental results, finding fair agreement given the
spread in estimates of the bulk modulus. The spin resonance linewidth is also
found to depend on pressure. This is explained by considering the
pressure-dependent viscosity of the solvent, which modifies the effect of
dipolar coupling between spins within fullerene clusters.",1712.05991v1
2018-03-16,Revealing weak spin-orbit coupling effects on charge carriers in a $π$-conjugated polymer,"We measure electrically detected magnetic resonance (EDMR) on organic
light-emitting diodes (OLEDs) made of the polymer
poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) at room
temperature and high magnetic fields, where spectral broadening of the
resonance due to spin-orbit coupling (SOC) exceeds that due to the local
hyperfine fields. Density-functional-theory calculations on an open-shell model
of the material reveal g-tensors of charge-carrier spins in the lowest
unoccupied (electron) and highest occupied (hole) molecular orbitals. These
tensors are used for simulations of magnetic resonance line-shapes. Besides
providing the first quantification and direct observation of SOC effects on
charge-carrier states in these weakly SO-coupled hydrocarbons, this procedure
demonstrates that spin-related phenomena in these materials are fundamentally
monomolecular in nature.",1803.06052v1
2018-09-17,Efimov Enhanced Kondo Effect in Alkaline and Alkaline-Earth Atomic Gas Mixture,"Recent experiment has observed Feshbach resonances between alkaline and
alkaline-earth atoms. These Feshbach resonances are insensitive to the nuclear
spin of alkaline-earth atoms. Ultilizing this feature, we propose to take this
system as a candidate to perform quantum simulation of the Kondo effect. An
alkaline atom can form a molecule with an alkaline-earth atom with different
nuclear spins, which plays the role of spin-exchange scattering responsible for
the Kondo effect. Furthermore, we point out that the existence of three-body
bound state and atom-molecule resonance due to the Efimov effect can enhance
this spin-exchange scattering, and therefore enhance the Kondo effect. We
discuss this mechanism first with a three-body problem in free space, and then
demonstrate that the same mechanism still holds when the alkaline atom is
localized by an external trap and becomes an impurity embedded in the
alkaline-earth atomic gases.",1809.06340v1
2018-09-26,Echo trains in pulsed electron spin resonance of a strongly coupled spin ensemble,"We report on a novel dynamical phenomenon in electron spin resonance
experiments of phosphorus donors. When strongly coupling the paramagnetic
ensemble to a superconducting lumped element resonator, the coherent exchange
between these two subsystems leads to a train of periodic, self-stimulated
echos after a conventional Hahn echo pulse sequence. The presence of these
multi-echo signatures is explained using a simple model based on spins rotating
on the Bloch sphere, backed up by numerical calculations using the
inhomogeneous Tavis-Cummings Hamiltonian.",1809.10116v3
2020-04-27,Optically detected magnetic resonance in neutral silicon vacancy centers in diamond via bound exciton states,"Neutral silicon vacancy (SiV0) centers in diamond are promising candidates
for quantum networks because of their excellent optical properties and long
spin coherence times. However, spin-dependent fluorescence in such defects has
been elusive due to poor understanding of the excited state fine structure and
limited off-resonant spin polarization. Here we report the realization of
optically detected magnetic resonance and coherent control of SiV0 centers at
cryogenic temperatures, enabled by efficient optical spin polarization via
previously unreported higher-lying excited states. We assign these states as
bound exciton states using group theory and density functional theory. These
bound exciton states enable new control schemes for SiV0 as well as other
emerging defect systems.",2004.12544v2
2017-10-02,Chirp Mixing,"In this paper, we develop the theory of chirp mixing. The working principle
is simple, given coupled homonuclear spins with offsets in range [-B, B], we
adiabatically sweep through the resonances. This achieves cross polarization
between the z magnetization of the coupled spins. We repeat this basic
operation many times with a supercycle to achieve appropriate mixing time. When
we sweep through the resonances, midway between the resonances of the coupled
spin I and S, the effective field seen by two spins is the same and hence they
precess at same frequency around their effective fields. This means the
coupling, which normally gets averaged due to the chemical shift difference is
no more averaged for a short time and we get mixing. In this paper, we develop
these basic ideas. By virtue of its design, the chirp mixing is much more
broadband compared to state of the art methods. The proposed methodology is
demonstrated on 13C mixing in a sample of Alanine.",1710.00488v2
2020-11-16,The multichannel nature of three-body recombination for ultracold $^{39}$K,"We develop a full multichannel spin model in momentum space to investigate
three-body recombination of identical alkali-metal atoms colliding in a
magnetic field. The model combines the exact three-atom spin structure and
realistic pairwise atom-atom interactions. By neglecting the interaction
between two particles when the spectating particle is not in its initial spin
state we arrive at an approximate model. With this approximate model we achieve
excellent agreement with the recent precise measurement of the ground Efimov
resonance position in potassium-39 close to 33.58 G [Chapurin $et$ $al$., Phys.
Rev. Lett. 123, 233402 (2019)]. We analyze the limitations of our approximation
by comparing to the numerical results for the full system and find that it
breaks down for Feshbach resonances at larger magnetic fields in the same spin
channel. There the relevant three-body closed channel thresholds are much
closer to the open channel threshold, which enhances the corresponding
multichannel couplings. Therefore the neglected components of the interaction
should be included for those Feshbach resonances.",2011.07943v1
2021-08-13,Optical signatures of the coupled spin-mechanics of a levitated magnetic microparticle,"We propose a platform that combines the fields of cavity optomagnonics and
levitated optomechanics in order to control and probe the coupled
spin-mechanics of magnetic dielectric particles. We theoretically study the
dynamics of a levitated Faraday-active dielectric microsphere serving as an
optomagnonic cavity, placed in an external magnetic field and driven by an
external laser. We find that the optically driven magnetization dynamics
induces angular oscillations of the particle with low associated damping.
Further, we show that the magnetization and angular motion dynamics can be
probed via the power spectrum of the outgoing light. Namely, the characteristic
frequencies attributed to the angular oscillations and the spin dynamics are
imprinted in the light spectrum by two main resonance peaks. Additionally, we
demonstrate that a ferromagnetic resonance setup with an oscillatory
perpendicular magnetic field can enhance the resonance peak corresponding to
the spin oscillations and induce fast rotations of the particle around its
anisotropy axis.",2108.06214v1
2019-12-27,Gigantic spin-noise gain enables magnetic resonance spectroscopy of impurity crystals,"Spin noise spectroscopy is a method of magnetic resonance widely used,
nowadays, in atomic and semiconductor research. Classical objects of the EPR
spectroscopy - dielectrics with paramagnetic impurities - seemed to be
unsuitable for this technique because of large widths of allowed optical
transitions and, therefore, low specific Faraday rotation (FR). We show,
however, that the FR noise detected at the wavelength of a weak optical
transition (with low regular FR) may increase by many orders of magnitude as
its homogeneous width decreases. This spin-noise gain effect, numerically
described by the ratio of the inhomogeneous linewidth to homogeneous, relates
primarily to forbidden intraconfigurational transitions of impurity ions with
unfilled inner electronic shells. Specifically, for the f-f transitions of
rare-earth ions in crystals, this factor may reach 10$^8$. In this paper, we
report on the first successful application of spin noise spectroscopy for
detecting magnetic resonance of rare-earth ions in crystals.",1912.12100v1
2021-12-06,Excited-state spectroscopy of spin defects in hexagonal boron nitride,"We used optically detected magnetic resonance (ODMR) technique to directly
probe electron-spin resonance transitions in the excited state of
negatively-charged boron vacancy (VB-) defects in hexagonal boron nitride (hBN)
at room temperature. The data showed that the excited state has a zero-field
splitting of ~ 2.1 GHz, a g factor similar to the ground state and two types of
hyperfine splitting ~ 90 MHz and ~ 18.8 MHz respectively. Pulsed ODMR
experiments were conducted to further verify observed resonant peaks
corresponding to spin transitions in the excited state. In addition, negative
peaks in photoluminescence and ODMR contrast as a function of magnetic field
magnitude and angle at level anti-crossing were observed and explained by
coherent spin precession and anisotropic relaxation. This work provided
significant insights for studying the structure of VB- excited states, which
might be used for quantum information processing and nanoscale quantum sensing.",2112.02912v1
2022-05-20,Quantum Heterodyne Sensing of Nuclear Spins via Double Resonance,"Nanoscale nuclear magnetic resonance (NMR) signals can be measured through
hyperfine interaction to paramagnetic electron sensor spins. A heterodyne
approach is widely used to overcome the electron spin lifetime limit in
spectral resolution. It uses a series of modified Hahn echo pulse sequences
applied coherently with precession signal resulting in a subsampled NMR signal.
Due to challenges with applying high electron Rabi frequencies its application
is limited to low fields, thus the full potential of the method is not yet
exploited at high magnetic fields, beneficial for NMR. Here we present
heterodyne detection utilizing a series of phase coherent electron nuclear
double resonance sensing blocks which extends nanoscale NMR protocols to
arbitrary magnetic fields. We demonstrate this principle on a single NV center,
both with an intrinsic $^{14}$N and a weekly coupled $^{13}$C nuclear spin in
the bath surrounding single NV centres. We compare our protocol to existing
heterodyne protocols and discuss its prospects. This work paves the way towards
high field nanoscale heterodyne NMR protocols with NV centres which is crucial
for reducing sample volumes and improving chemical resolution.",2205.10182v1
2023-08-29,Readout using Resonant Tunneling in Silicon Spin Qubits,"Spin qubit systems are one of the promising candidates for quantum computing.
The quantum dot (QD) arrays are intensively investigated by many researchers.
Because the energy-difference between the up-spin and down-spin states is very
small, the detection of the qubit state is of prime importance in this field.
Moreover, many wires are required to control qubit systems. Therefore, the
integration of qubits and wires is also an important issue. In this study, the
measurement process of QD arrays is theoretically investigated using resonant
tunneling, controlled by a conventional transistor. It is shown that the number
of possible measurements during coherence time can exceed a hundred under the
backaction of the measurements owing to the nonlinear characteristics of
resonant tunneling. It is also discussed to read out the measurement results by
the conventional transistor.",2308.15015v1
1998-11-27,Are the production and decay of a resonance always independent?,"The widely accepted assumption that the decay of a resonance proceeds
independently of its production, quantitatively expressed as a factorizing
formula for the differential cross section in the invariant mass of unpolarized
resonance debris, is put under scrutiny. It is shown that the factorization is
always valid for scalar and pseudoscalar resonances, although the usual version
of the formula is not entirely correct. For resonances with nonzero spins the
factorization does not generally take place. We deal in more detail with the
spin-one case, where we show a condition on the decay matrix element that
ensures the validity of the same factorizing formula as in the spinless case.
This condition is satisfied for rho --> pi pi but not, e.g., for K* --> pi K or
a1 --> pi rho. The formalism is applied also to the case when the resonance is
produced not in two-body collisions but in the decay of a heavier particle or
resonance (chain decay). Application of our formulas to the e+e- production in
one-photon approximation agrees with what is known from quantum electrodynamics
and thus provides another test of their soundness.",9811493v1
2010-10-05,Lindblad resonance torques in relativistic discs: II. Computation of resonance strengths,"We present a fully relativistic computation of the torques due to Lindblad
resonances from perturbers on circular, equatorial orbits on discs around
Schwarzschild and Kerr black holes. The computation proceeds by establishing a
relation between the Lindblad torques and the gravitational waveforms emitted
by the perturber and a test particle in a slightly eccentric orbit at the
radius of the Lindblad resonance. We show that our result reduces to the usual
formula when taking the nonrelativistic limit. Discs around a black hole
possess an m=1 inner Lindblad resonance with no Newtonian Keplerian analogue;
however its strength is very weak even in the moderately relativistic regime
(r/M ~ few tens), which is in part due to the partial cancellation of the two
leading contributions to the resonant amplitude (the gravitoelectric octupole
and gravitomagnetic quadrupole). For equatorial orbits around Kerr black holes,
we find that the m=1 ILR strength is enhanced for retrograde spins and
suppressed for prograde spins. We also find that the torque associated with the
m>=2 inner Lindblad resonances is enhanced relative to the nonrelativistic
case; the enhancement is a factor of 2 for the Schwarzschild hole even when the
perturber is at a radius of 25M.",1010.0759v2
2011-07-28,Discovery in Drell-Yan Processes at the LHC,"We study the Drell-Yan process mediated by a new bosonic resonance at the
LHC. The bosons of spin-0, 1, and 2 with the most general leading-order
couplings to Standard Model fermions and gluons are considered, which provide a
model-independent formulation for future exploration of the resonance
properties, such as its spin, mass and couplings. In the case of neutral
resonances, we demonstrate how the shapes of the kinematical distributions
change as one varies the chiral couplings of the quarks and leptons, and show
how to analyze the couplings by making use of the forward-backward asymmetry.
In the case of charged resonances, we propose a novel technique to effectively
reconstruct the angular distribution in the center-of-mass frame, to a large
extent avoiding the two-fold ambiguity due to the missing neutrino. Similar to
the case of a neutral resonance, the spin information of the resonance can be
extracted unambiguously, and chiral couplings and the asymmetries can be
explored in a statistical manner. With the current LHC data, we present bounds
on the mass and cross section times branching fraction of the new resonance and
estimate the future reach.",1107.5830v1
2011-10-18,Signatures of low-scale string models at the LHC,"Low-scale string models, in which the string scale M_s is of the order of TeV
with large extra dimensions, can solve the problems of scale hierarchy and
non-renormalizable quantum gravity in the standard model. String excited states
of the standard model particles are possibly observed as resonances in the
dijet invariant mass distribution at the LHC. There are two properties to
distinguish whether the resonances are due to low-scale string or some other
""new physics"". One is a characteristic angular distribution in dijet events at
the resonance due to spin degeneracy of string excited states, and the other is
an appearance of the second resonance at a characteristic mass of second string
excited states. We investigate a possibility to observe these evidences of
low-scale string models by Monte Carlo simulations with a reference value of
M_s = 4 TeV at sqrt{s} = 14 TeV. It is shown that spin degeneracy at the dijet
resonance can be observed by looking the chi-distribution with integrated
luminosity of 20 fb^-1. It is shown that the second resonance can be observed
at rather close to the first resonance in the dijet invariant mass distribution
with integrated luminosity of 50 fb^-1. These are inevitable signatures of
low-scale string models.",1110.3976v4
2012-07-04,Bandwidth-Limited Control and Ringdown Suppression in High-Q Resonators,"We describe how the transient behavior of a tuned and matched resonator
circuit and a ringdown suppression pulse may be integrated into an optimal
control theory (OCT) pulse-design algorithm to derive control sequences with
limited ringdown that perform a desired quantum operation in the presence of
resonator distortions of the ideal waveform. Inclusion of ringdown suppression
in numerical pulse optimizations significantly reduces spectrometer deadtime
when using high quality factor (high-Q) resonators, leading to increased
signal-to-noise ratio (SNR) and sensitivity of inductive measurements. To
demonstrate the method, we experimentally measure the free-induction decay of
an inhomogeneously broadened solid-state free radical spin system at high Q.
The measurement is enabled by using a numerically optimized bandwidth-limited
OCT pulse, including ringdown suppression, robust to variations in static and
microwave field strengths. We also discuss the applications of pulse design in
high-Q resonators to universal control of anisotropic-hyperfine coupled
electron-nuclear spin systems via electron-only modulation even when the
bandwidth of the resonator is significantly smaller than the hyperfine coupling
strength. These results demonstrate how limitations imposed by linear response
theory may be vastly exceeded when using a sufficiently accurate system model
to optimize pulses of high complexity.",1207.1139v2
2016-04-28,Universal Symmetry-Protected Resonances in a Spinful Luttinger Liquid,"We study the problem of resonant tunneling through a quantum dot in a spinful
Luttinger liquid. For a range of repulsive interactions, we find that for
symmetric barriers there exist resonances with a universal peak conductance
$2g^* e^2/h$ that are controlled by a non-trivial intermediate fixed point.
This fixed point is also a quantum critical point separating symmetry-protected
topological phases. By tuning the system through resonance, all SPT phases can
be accessed. For a particular interaction strength with Luttinger parameters
$g_\rho=1/3$ and $g_\sigma=1$, we show that the problem is equivalent to a two
channel $SU(3)$ Kondo problem($SU(3)_2$ CFT). At the Toulouse limit, both
problems can be mapped to a quantum Brownian motion model on a Kagome lattice,
which in turn is related to the quantum Brownian motion on a honeycomb lattice
and the three-channel $SU(2)$ Kondo problem($SU(2)_3$ CFT). ""Level-rank
duality"" in the quantum Brownian motion model relating $SU(2)_k$ CFT to
$SU(k)_2$ CFT is also explored. Utilizing the boundary conformal field theory,
the on-resonance conductance of our resonant tunneling problem is calculated as
well as the scaling dimension of the leading relevant operator. This allows us
to compute the scaling behavior of the resonance line-shape as a function of
temperature.",1604.08280v2
2016-05-23,Electron doping evolution of the neutron spin resonance in NaFe$_{1-x}$Co$_{x}$As,"Neutron spin resonance, a collective magnetic excitation coupled to
superconductivity, is one of the most prominent features shared by a broad
family of unconventional superconductors including copper oxides, iron
pnictides, and heavy fermions. In this work, we study the doping evolution of
the resonances in NaFe$_{1-x}$Co$_x$As covering the entire superconducting
dome. For the underdoped compositions, two resonance modes coexist. As doping
increases, the low-energy resonance gradually loses its spectral weight to the
high-energy one but remains at the same energy. By contrast, in the overdoped
regime we only find one single resonance, which acquires a broader width in
both energy and momentum, but retains approximately the same peak position even
when $T_c$ drops by nearly a half compared to optimal doping. These results
suggest that the energy of the resonance in electron overdoped
NaFe$_{1-x}$Co$_x$As is neither simply proportional to $T_c$ nor the
superconducting gap, but is controlled by the multi-orbital character of the
system and doped impurity scattering effect.",1605.06890v1
2020-11-17,Dispersive measurement of a semiconductor double quantum dot via 3D integration of a high-impedance TiN resonator,"Spins in semiconductor quantum dots are a candidate for cryogenic quantum
processors due to their exceptionally long coherence times. One major challenge
to scaling quantum dot spin qubits is the dense wiring requirements, making it
difficult to envision fabricating large arrays of nearest-neighbor-coupled
qubits necessary for error correction. We describe a method to solve this
problem by spacing the qubits out using high-impedance superconducting
resonators with a 2D grid unit cell area of $0.16~\text{mm}^2$ using 3D
integration. To prove the viability of this approach, we demonstrate 3D
integration of a high-impedance TiN resonator coupled to a double quantum dot
in a Si/SiGe heterostructure. Using the resonator as a dispersive gate sensor,
we tune the device down to the single electron regime with an SNR = 5.36
limited by the resonator-dot capacitance. Characterization of the dot and
resonator systems shows such integration can be done while maintaining low
charge noise metrics for the quantum dots and with improved loaded quality
factors for the superconducting resonator ($Q_L = 2.14 \times 10^4$), allowing
for high-sensitivity charge detection and the potential for high fidelity
2-qubit gates. This work paves the way for 2D quantum dot qubit arrays with
cavity mediated interactions.",2011.08759v1
2020-05-29,Electron spin resonance and ferromagnetic resonance spectroscopy in the high-field phase of the van der Waals magnet CrCl$_3$,"We report a comprehensive high-field/high-frequency electron spin resonance
(ESR) study on single crystals of the van der Waals magnet CrCl$_3$. This
material, although being known for quite a while, has received recent
significant attention in a context of the use of van der Waals magnets in novel
spintronic devices. Temperature-dependent measurements of the resonance fields
were performed between 4 and 175 K and with the external magnetic field applied
parallel and perpendicular to the honeycomb planes of the crystal structure.
These investigations reveal that the resonance line shifts from the
paramagnetic resonance position already at temperatures well above the
transition into a magnetically ordered state. Thereby the existence of
ferromagnetic short-range correlations above the transition is established and
the intrinsically two-dimensional nature of the magnetism in the title compound
is proven. To study details of the magnetic anisotropies in the field-induced
effectively ferromagnetic state at low temperatures, frequency-dependent
ferromagnetic resonance (FMR) measurements were conducted at 4 K. The observed
anisotropy between the two magnetic-field orientations is analyzed by means of
numerical simulations based on a phenomenological theory of FMR. These
simulations are in excellent agreement with measured data if the shape
anisotropy of the studied crystal is taken into account, while the
magnetocrystalline anisotropy is found to be negligible in CrCl$_3$. The
absence of a significant intrinsic anisotropy thus renders this material as a
practically ideal isotropic Heisenberg magnet.",2005.14559v1
2023-09-28,Constraining Ultralight Dark Matter through an Accelerated Resonant Search,"Experiments aimed at detecting ultralight dark matter typically rely on
resonant effects, which are sensitive to the dark matter mass that matches the
resonance frequency. In this study, we investigate the nucleon couplings of
ultralight axion dark matter using a magnetometer operating in a nuclear
magnetic resonance (NMR) mode. Our approach involves the use of a $^{21}$Ne
spin-based sensor, which features the lowest nuclear magnetic moment among
noble-gas spins. This configuration allows us to achieve an ultrahigh
sensitivity of 0.73 fT/Hz$^{1/2}$ at around 5 Hz, corresponding to energy
resolution of approximately 1.5$\times
  10^{-23}\,\rm{eV/Hz^{1/2}}$. Our analysis reveals that under certain
conditions it is beneficial to scan the frequency with steps significantly
larger than the resonance width. The analytical results are in agreement with
experimental data and the scan strategy is potentially applicable to other
resonant searches. Further, our study establishes stringent constraints on
axion-like particles (ALP) in the 4.5--15.5 Hz Compton-frequency range coupling
to neutrons and protons, improving on prior work by several-fold. Within a band
around 4.6--6.6 Hz and around 7.5 Hz, our laboratory findings surpass
astrophysical limits derived from neutron-star cooling. Hence, we demonstrate
an accelerated resonance search for ultralight dark matter, achieving an
approximately 30-fold increase in scanning step while maintaining competitive
sensitivity.",2309.16600v1
2020-12-12,Ultrafast spin-currents and charge conversion at 3d-5d interfaces probed by time-domain terahertz spectroscopy,"Spintronic structures are extensively investigated for their spin orbit
torque properties, required for magnetic commutation functionalities. Current
progress in these materials is dependent on the interface engineering for the
optimization of spin transmission. Here, we advance the analysis of ultrafast
spin-charge conversion phenomena at ferromagnetic-transition metal interfaces
due to their inverse spin-Hall effect properties. In particular the intrinsic
inverse spin Hall effect of Pt-based systems and extrinsic inverse spin-Hall
effect of Au:W and Au:Ta in NiFe/Au:(W,Ta) bilayers are investigated. The
spin-charge conversion is probed by complementary techniques -- ultrafast THz
time domain spectroscopy in the dynamic regime for THz pulse emission and
ferromagnetic resonance spin-pumping measurements in the GHz regime in the
steady state -- to determine the role played by the material properties,
resistivities, spin transmission at metallic interfaces and spin-flip rates.
These measurements show the correspondence between the THz time domain
spectroscopy and ferromagnetic spin-pumping for the different set of samples in
term of the spin mixing conductance. The latter quantity is a critical
parameter, determining the strength of the THz emission from spintronic
interfaces. This is further supported by ab-initio calculations, simulations
and analysis of the spin-diffusion and spin relaxation of carriers within the
multilayers in the time domain, permitting to determine the main trends and the
role of spin transmission at interfaces. This work illustrates that time domain
spectroscopy for spin-based THz emission is a powerful technique to probe
spin-dynamics at active spintronic interfaces and to extract key material
properties for spin-charge conversion.",2012.06900v1
1998-11-23,Spin-Wave Excitations of Half-Filled Kondo Lattice Model,"The spin excitations in the antiferromagnetic phase of half-filled Kondo
lattice model are studied by means of the decoupling approximation for spin
Green's function. The spin-wave spectrum is calculated as a function of Kondo
coupling, and this is used to calculate the thermodynamic quantities at low
temperatures. The N\'{e}el temperature of the form
  $T_{\rm N}=0.087{J}^2\ln{(1/J)}$ is obtained for the 3-dimensional case in
the weak-coupling limit. It is pointed out that the ratio of the spin-wave
velocity to the N\'{e}el temperature $v_s/T_{\rm N}$ is enhanced as the Kondo
coupling becomes small, reflecting the long-range nature of effective
interactions between localized spins.",9811316v1
2000-11-28,Spin wave dispersion softening in the ferromagnetic Kondo lattice model for manganites,"Spin dynamics is calculated in the ferromagnetic (FM) state of the
generalized Kondo lattice model taking into account strong on-site correlations
between e_g electrons and antiferromagnetic (AFM) exchange among t_{2g} spins.
Our study suggests that competing FM double-exchange and AFM super-exchange
interaction lead to a rather nontrivial spin-wave spectrum. While spin
excitations have a conventional Dq^2 spectrum in the long-wavelength limit,
there is a strong deviation from the spin-wave spectrum of the isotropic
Heisenberg model close to the zone boundary. The relevance of our results to
the experimental data are discussed.",0011464v1
2005-06-04,Soliton solution of continuum magnetization-equation in conducting ferromagnet with a spin-polarized current,"Exact soliton solutions of a modified Landau-Lifshitz equation for the
magnetization of conducting ferromagnet in the presence of a spin-polarized
current are obtained by means of inverse scattering transformation. From the
analytical solution effects of spin-current on the frequency, wave number, and
dispersion law of spin wave are investigated. The one-soliton solution
indicates obviously current-driven precession and periodic shape-variation as
well. The inelastic collision of solitons by which we mean the shape change
before and after collision appears due to the spin current. We, moreover, show
that complete inelastic collisions can be achieved by adjusting spectrum and
current parameters. This may lead to a potential technique for shape control of
spin wave.",0506103v1
2005-11-09,Current driven magnetization dynamics in helical spin density waves,"A mechanism is proposed for manipulating the magnetic state of a helical spin
density wave using a current. In this paper, we show that a current through a
bulk system with a helical spin density wave induces a spin transfer torque,
giving rise to a rotation of the order parameter.The use of spin transfer
torque to manipulate the magnetization in bulk systems does not suffer from the
obstacles seen for magnetization reversal using interface spin transfer torque
in multilayered systems. We demonstrate the effect by a quantitative
calculation of the current induced magnetization dynamics of Erbium. Finally we
propose a setup for experimental verification.",0511224v2
2006-01-22,Thermodynamic properties of the ferrimagnetic spin chains in the presence of a magnetic field,"We have implemented three approaches to describe the thermodynamic properties
of ferrimagnetic ($S=5/2, s=2$) spin chains. The application of cumulant
expansion has been generalized to the ferrimagnetic chain in the presence of an
external magnetic field. Using cumulants, we have obtained the field dependent
effective Hamiltonian in terms of the classical variables up to the second
order of quantum corrections. Thermodynamic functions, the internal energy, the
specific heat and the magnetic susceptibility are obtained from the effective
Hamiltonian. We have also examined the modified spin wave theory to derive the
same physical properties. Finally, we have studied our model using quantum
Monte Carlo simulation to obtain accurate results. The comparison of the above
results and also the high temperature series expansion shows that cumulant
expansion gives good results for moderate and high temperature regions while
the modified spin wave theory is good for low temperatures. Moreover, the
convergence regions of the cumulant expansion and the modified spin wave theory
overlap each other which propose these two as a set of complement methods to
get the thermodynamic properties of spin models.",0601494v1
2006-02-18,Spin waves in quasi-equilibrium spin systems,"Using the Landau Fermi liquid theory we have discovered a new regime for the
propagation of spin waves in a quasi-equilibrium spin systems. We have
determined the dispersion relation for the transverse spin waves and found that
one of the modes is gapless. The gapless mode corresponds to the precessional
mode of the magnetization in a paramagnetic system in the absence of an
external magnetic field. One of the other modes is gapped which is associated
with the precession of the spin current around the internal field. The gapless
mode has a quadratic dispersion leading to some interesting thermodynamic
properties including a $T^{3/2}$ contribution to the specific heat. We also
show that these modes make significant contributions to the dynamic structure
function.",0602435v1
2006-03-03,Spin-flop transitions and spin-wave gaps in La_2CuO_4,"We study the spin-wave spectrum and the spin-flop transitions in La_2CuO_4 in
a uniform magnetic field at zero temperature. Using the non-linear sigma-model,
we show that a field applied along the orthorhombic b direction leads to a
two-step rotation of the staggered magnetization, first in the bc and then in
the ac plane, until the order parameter is completely aligned along the c axis.
In contrast, for a perpendicular magnetic field, we find a conventional
spin-flop transition induced by the competition between the field and the
interlayer coupling. A comparison with recent measurements of the
field-dependence of the in-plane spin-wave gap shows a beautiful agreement
between theory and experiments.",0603061v2
2007-03-07,Effective action of the weakly doped t-J model and spin-wave excitations in the spin-glass phase of La_{2-x}Sr_xCuO_4,"We derive the low-energy effective field theory of the extended t-J model in
the regime of light doping. The action includes a previously unknown Berry
phase term, which is discussed in detail. We use this effective field theory to
calculate spin-wave excitations in the disordered spin spiral state of
La_{2-x}Sr_xCuO_4 (the spin-glass phase). We predict an excitation spectrum
with two distinct branches: The in-plane mode has the usual linear spin-wave
dispersion and the out-of-plane mode shows non-trivial doping dependent
features. We also calculate the intensities for inelastic neutron scattering in
these modes.",0703172v1
2008-02-29,Numerical Relativity meets Data Analysis: Spinning Binary Black Hole Case,"We present a study of the gravitational waveforms from a series of spinning,
equal-mass black hole binaries focusing on the harmonic content of the waves
and the contribution of the individual harmonics to the signal-to-noise ratio.
The gravitational waves were produced from two series of evolutions with black
holes of initial spins equal in magnitude and anti-aligned with each other. In
one series the magnitude of the spin is varied; while in the second, the
initial angle between the black-hole spins and the orbital angular momentum
varies. We also conduct a preliminary investigation into using these waveforms
as templates for detecting spinning binary black holes. Since these runs are
relativity short, containing about two to three orbits, merger and ringdown, we
limit our study to systems of total mass greater than 50 solar masses. This
choice ensures that our waveforms are present in the ground-based detector band
without needing addition gravitational wave cycles. We find that while the mode
contribution to the signal-to-noise ratio varies with the initial angle, the
total mass of the system caused greater variations in the match.",0802.4427v1
2010-11-16,Photon spin operator and Pauli matrix,"Any polarization vector of a plane wave can be decomposed into a pair of
mutually orthogonal base vectors, known as a polarization basis. Regarding this
decomposition as a quasi-unitary transformation from a three-component vector
to a corresponding two-component spinor, one is led to a representation
formalism for the photon spin. The spin operator $\hat{\boldsymbol \gamma}$
defined on the space of unit spinors, referred to as the Jones space, has only
component along the wave vector and is represented by one of the Pauli matrices
in the commonly used polarization basis. It is deformed by the quasi-unitary
transformation from the spin operator that is defined on the space of unit
polarization vectors, referred to as the Pancharatnam space. On the basis of
this theory, it is shown that the Cartesian components of spin operator
$\hat{\boldsymbol \gamma}$ are mutually commutative and the spin angular
momentum in units of $\hbar$ is exactly the component of the Stokes vector
along the wave vector.",1011.3608v1
2012-01-13,Does a Surface Polariton Have Spin?,"We consider a p-polarized surface electromagnetic wave (a classical surface
polariton) at the interface between the vacuum and a metal or left-handed
medium. We show that the evanescent electromagnetic waves forming the surface
polariton inevitably possess a backward spin energy flow, which, together with
a superluminal orbital energy flow, form the total Poynting vector. This spin
energy flow generates a well-defined (but not quantized) spin angular momentum
of surface polaritons which is orthogonal to the propagation direction. The
spin of evanescent waves arises from the imaginary longitudinal component of
the electric field which makes the polarization effectively elliptical in the
propagation plane. We also examine the connection between the spin and
chirality of evanescent modes.",1201.2746v3
2012-10-09,"Spin Wave Excitations in AFe$_{1.5}$Se$_2$ (A=K, Tl): Analytical Study","We have analytically solved the spin wave excitations for the intercalated
ternary iron-selenide AFe$_{1.5}$Se$_2$ (A=K, Tl) in the $4\times 2$ collinear
antiferromagnetic order. It is found that there are one acoustic branch
(gapless Goldstone mode) and two gapful optical branches of spin wave
excitations with each in double degeneracy. By examining the non-imaginary
excitation frequency condition, we can determine the corresponding phase
boundary. The exchange couplings between Fe moments in AFe$_{1.5}$Se$_2$ are
derived based on the first-principles total energy calculations. The Fe spin is
found to be $S=3/2$ through computing the antiferromagnetic quantum
fluctuation. And it is further found that a very small spin-orientation
anisotropy can remarkably suppress the antiferromagnetic quantum fluctuation.
The spin dynamical structure factors are calculated and discussed in
association with neutron inelastic scattering experiment.",1210.2668v1
2012-11-30,Paramagnetic spin excitations in insulating Rb$_{0.8}$Fe$_{1.6}$Se$_2$,"We use neutron scattering to study temperature dependent spin excitations in
insulating antiferromagnetic (AF) Rb$_{0.8}$Fe$_{1.6}$Se$_2$. In the
low-temperature AF state, spin waves can be accurately described by a local
moment Heisenberg Hamiltonian. On warming to around the Neel temperature of
T_N=500$ K, low-energy (E<30meV) paramagnetic spin excitations form
Lorentzian-like quasielastic peaks centered at the AF wave vectors associated
with spin waves, while high-energy (E>50meV) spin excitations become heavily
damped. Upon further warming to above the structural distortion temperature of
T_s=524K, the entire paramagnetic excitations become overdamped. These results
suggest that AF Rb$_{0.8}$Fe$_{1.6}$Se$_2$ is not a copper-oxide-like Mott
insulator, and has less electron correlations compared with metallic iron
pnictides and iron chalcogenides.",1211.7328v1
2014-01-06,Order by Disorder Spin Wave Gap in the XY Pyrochlore Magnet Er2Ti2O7,"The recent determination of a robust spin Hamiltonian for the
anti-ferromagnetic XY pyrochlore Er2Ti2O7 reveals a most convincing case of the
""order by quantum disorder"" (ObQD) mechanism for ground state selection. This
mechanism relies on quantum fluctuations to remove an accidental symmetry of
the magnetic ground state, and selects a particular ordered spin structure
below T_N=1.2K. The removal of the continuous degeneracy results in an energy
gap in the spectrum of spin wave excitations, long wavelength pseudo-Goldstone
modes. We have measured the ObQD spin wave gap at a zone center in Er2Ti2O7,
using low incident energy neutrons and the time-of-flight inelastic scattering
method. We report a gap of Delta =0.053 +/- 0.006 meV, which is consistent with
upper bounds placed on it from heat capacity measurements and roughly
consistent with theoretical estimate of ~ 0.02 meV, further validating the spin
Hamiltonian that led to that prediction. The gap is observed to vary with
square of the order parameter, and goes to zero for T ~ T_N.",1401.1176v2
2014-03-12,Crossover from spin-waves to diffusive spin excitations in underdoped Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$,"Using inelastic neutron scattering, we show that the onset of
superconductivity in underdoped Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$ coincides
with a crossover from well-defined spin waves to overdamped and diffusive spin
excitations. This crossover occurs despite the presence of long-range stripe
antiferromagnetic order for samples in a compositional range from x=0.04-0.055,
and is a consequence of the shrinking spin-density wave gap and a corresponding
increase in the particle-hole (Landau) damping. The latter effect is captured
by a simple itinerant model relating Co doping to changes in the hot spots of
the Fermi surface. We argue that the overdamped spin fluctuations provide a
pairing mechanism for superconductivity in these materials.",1403.2793v1
2014-04-03,Spin liquid phase in the semiclassical theory of the Heisenberg model on an anisotropic triangular lattice with ring exchange,"We investigate the effect of ring-exchange on the ground-state properties and
magnetic excitations of the $S = 1/2$ Heisenberg model on the anisotropic
triangular lattice with ring-exchange at $T = 0$ using linear spin-wave theory.
Classically, we find stable N\'{e}el, spiral and collinear magnetically ordered
phases. Upon including quantum fluctuations to the model, linear spin-wave
theory shows that ring exchange induces a large quantum disordered region in
the phase diagram, completely wiping out the classically stable collinear
phase. Analysis of the spin-wave spectra for each of these three models
demonstrates that the large spin-liquid phase observed in the full model is a
direct manifestation of competing classical orders. To understand the origin of
these competing phases we introduce models where either the four spin
contributions from ring exchange, or the renormalization of the Heisenberg
terms due to ring exchange are neglected. We find that these two terms favor
rather different physics.",1404.0769v1
2016-07-03,Spin waves and magnetic exchange interactions in the spin ladder compound RbFe$_2$Se$_3$,"We report an inelastic neutron scattering study of the spin waves of the
one-dimensional antiferromagnetic spin ladder compound RbFe$_2$Se$_3$. The
results reveal that the products, $SJ$'s, of the spin $S$ and the magnetic
exchange interactions $J$'s along the antiferromagnetic (leg) direction and the
ferromagnetic (rung) direction are comparable with those for the stripe ordered
phase of the parent compounds of the iron-based superconductors. The
universality of the $SJ$'s implies nearly universal spin wave dynamics and the
irrelevance of the fermiology for the existence of the stripe antiferromagnetic
order among various Fe-based materials.",1607.00639v1
2018-01-10,Spin dynamics and Andreev-Bashkin effect in mixtures of one-dimensional Bose gases,"We investigate the propagation of spin waves in two-component mixtures of
one-dimensional Bose gases interacting through repulsive contact potentials. By
using quantum Monte Carlo methods we calculate static ground-state properties,
such as the spin susceptibility and the spin structure factor, as a function of
both the intra-species and inter-species coupling strength and we determine the
critical parameters for phase separation. In homogeneous mixtures, results of
the velocity of spin waves and of its softening close to the critical point of
phase separation are obtained by means of a sum-rule approach. We quantify the
non-dissipative drag effect, resulting from the Andreev-Bashkin current-current
interaction between the two components of the gas, and we show that in the
regime of strong coupling it causes a significant suppression of the spin-wave
velocity.",1801.03446v2
2018-02-05,Micromagnetic view on ultrafast magnon generation by femtosecond spin current pulses,"In this Article we discuss a micromagnetic modelling approach to describe the
ultrafast spin-transfer torque excitation of coherent and incoherent magnons on
the nanoscale. Implementing the action of a femtosecond spin current pulse
entering an orthogonally magnetized thin ferromagnetic film, we reproduce
recent experimental results and reveal the factors responsible for the unequal
excitation efficiency of various spin waves. Our findings are in an excellent
agreement with the results of an analytical description of spin-wave excitation
based on classical kinetic equations. Furthermore, we suggest an experimental
design allowing for the excitation of laterally propagating spin waves beyond
the optical diffraction limit. Our findings demonstrate that the classical
micromagnetic picture retains its predictive and interpretative power on
femtosecond temporal and nanometer spatial scales.",1802.01305v1
2021-04-22,Spin orbit torque nano-oscillators by dipole field-localized spin wave modes,"We demonstrate a high-quality spin orbit torque nano-oscillator comprised of
spin wave modes confined by the magnetic field by the strongly inhomogeneous
dipole field of a nearby micromagnet. This approach enables variable spatial
confinement and systematic tuning of magnon spectrum and spectral separations
for studying the impact of multi-mode interactions on auto-oscillations. We
find these dipole field-localized spin wave modes exhibit good characteristic
properties as auto-oscillators--narrow linewidth and large amplitude--while
persisting up to room temperature. We find that the linewidth of the
lowest-lying localized mode is approximately proportional to temperature in
good agreement with theoretical analysis of the impact of thermal fluctuations.
This demonstration of a clean oscillator with tunable properties provides a
powerful tool for understanding the fundamental limitations and linewidth
contributions to improve future spin-Hall oscillators.",2104.10838v3
2019-04-22,An overview of the gravitational spin Hall effect,"In General Relativity, the propagation of electromagnetic waves is usually
described by the vacuum Maxwell's equations on a fixed curved background. In
the limit of infinitely high frequencies, electromagnetic waves can be
localized as point particles, following null geodesics. However, at finite
frequencies, electromagnetic waves can no longer be treated as point particles
following null geodesics, and the spin angular momentum of light comes into
play, via the spin-curvature coupling. We will refer to this effect as the
gravitational spin Hall effect of light. Here, we review a series of
theoretical results related to the gravitational spin Hall effect of light, and
we compare the predictions of different models. The analogy with the spin Hall
effect in Optics is also explored, since in this field the effect is well
understood, both theoretically and experimentally.",1904.09963v1
2019-09-18,Micromagnetic Modeling of Telegraphic Mode Jumping in Microwave Spin Torque Oscillators,"The time domain stability of microwave spin torque oscillators (STOs) has
been investigated by systematic micromagnetic simulations. A model based on
internal spin wave reflection at grain boundaries with reduced exchange
coupling was implemented and used to study the oscillator under quasi-stable
operating conditions. Telegraphic mode jumping between two operating
frequencies (23.3 and 24.1 GHz) was observed in the time domain with
characteristic dwell times in the range of 10-100 ns. The oscillating volume
was shown to have a different shape at the distinct operating frequencies. The
shape difference is governed by spin wave reflections at the grain boundaries.
The resulting non-linear behavior of the oscillator was shown to be a
collective effect of spin wave scattering at different locations within a few
spin wavelengths from the nano-contact.",1909.08431v1
2020-10-01,"Spinor wave equation, relativistic condition, and nonlocality of photon spin","The purpose of this paper is to derive the photon spin and to deduce its
properties from a pair of quantum equations for the photon. To this end,
Darwin's equations are reinterpreted so as to meet the need of the quantum
mechanics of the photon. It is found that the photon wavefunction transforms
under Lorentz transformation as a spinor. The relativistic nature of the photon
is expressed through a constraint equation on the wavefunction in such a way
that the wave equation, which takes on the form of the Schr\""{o}dinger
equation, is not Lorentz covariant unless the constraint equation is taken into
account. The wave equation predicts the existence of a kind of spin, an
intrinsic degree of freedom. But the constraint equation makes the spin
nonlocal in the sense that no unique local density exists for the spin in
position space. The nonlocality of the photon spin is a reflection of the
nonlocality of the photon itself.",2010.00241v1
2022-02-08,Spin waves in spin hydrodynamics,"The propagation properties of spin degrees of freedom are analyzed in the
framework of relativistic hydrodynamics with spin based on the de Groot--van
Leeuwen--van Weert definitions of the energy-momentum and spin tensors. We
derive the analytical expression for the spin wave velocity for arbitrary
statistics and show that it goes to half the speed of light in the
ultra-relativistic limit. We find that only the transverse degrees of freedom
propagate, analogously to electromagnetic waves. Finally, we consider the
effect of dissipative corrections and calculate the damping coefficients for
the case of Maxwell-J\""uttner statistics.",2202.03952v2
2022-04-04,Spin-dependent phenomena at chiral temporal interfaces,"Temporally varying electromagnetic media have been extensively investigated
recently to unveil new means for controlling light. However, spin-dependent
phenomena in such media have not been explored thoroughly. Here, we reveal the
existence of spin-dependent phenomena at a temporal interface between chiral
and dielectric media. In particular, we show theoretically and numerically that
due to the material discontinuity in time, linearly polarized light is split
into forward-propagating right-handed and left-handed circularly polarized
waves having different angular frequencies and it the same phase velocities.
This salient effect allows complete temporal separation of the two spin states
of light with high efficiency. In addition, a phenomenon of spin-dependent
gain/loss is observed. Furthermore, we show that when the dielectric medium is
switched again to the original chiral medium, the right- and left-handed
circularly polarized light waves (with different angular frequencies) merge to
form a linearly polarized wave. Our findings extend spin-dependent interactions
of light from space to space-time.",2204.01574v3
2022-04-27,Elastic Spin and Orbital Angular Momenta,"Motivated by recent theoretical and experimental interest in the spin and
orbital angular momenta of elastic waves, we revisit canonical wave momentum,
spin, and orbital angular momentum in isotropic elastic media. We show that
these quantities are described by simple universal expressions, which differ
from the results of [G. J. Chaplain et al., Phys. Rev. Lett. 128, 064301
(2022)] and do not require separation of the longitudinal and transverse parts
of the wavefield. For cylindrical elastic modes, the normalized z-component of
the total (spin+orbital) angular momentum is quantized and equals the azimuthal
quantum number of the mode, while the orbital and spin parts are not quantized
due to the spin-orbit geometric-phase effects. In contrast to the claims of the
above article, longitudinal, transverse, and `hybrid' contributions to the
angular momenta are equally important and cannot be neglected. As another
application of the general formalism, we calculate the transverse spin angular
momentum of a surface Rayleigh wave.",2204.13037v3
2022-12-05,Spin wavepackets in the Kagome ferromagnet Fe$_3$Sn$_2$: propagation and precursors,"The propagation of spin waves in magnetically ordered systems has emerged as
a potential means to shuttle quantum information over large distances.
Conventionally, the arrival time of a spin wavepacket at a distance, $d$, is
assumed to be determined by its group velocity, $v_g$. He we report
time-resolved optical measurements of wavepacket propagation in the Kagome
ferromagnet Fe$_3$Sn$_2$ that demonstrate the arrival of spin information at
times significantly less than $d/v_g$. We show that this spin wave ""precursor""
originates from the interaction of light with the unusual spectrum of
magnetostatic modes in Fe$_3$Sn$_2$. Related effects may have far-reaching
consequences toward realizing long-range, ultrafast spin wave transport in both
ferromagnetic and antiferromagnetic systems.",2212.02498v1
2023-09-07,"Neutron spin echo is a ""quantum tale of two paths''","We describe an experiment that strongly supports a two-path interferometric
model in which the spin-up and spin-down components of each neutron propagate
coherently along spatially separated parallel paths in a typical neutron spin
echo small angle scattering (SESANS) experiment. Specifically, we show that the
usual semi-classical, single-path treatment of Larmor precession of a polarized
neutron in an external magnetic field predicts a damping as a function of the
spin echo length of the SESANS signal obtained with a periodic phase grating
when the transverse width of the neutron wave packet is finite. However, no
such damping is observed experimentally, implying either that the Larmor model
is incorrect or that the transverse extent of the wave packet is very large. In
contrast, we demonstrate theoretically that a quantum-mechanical
interferometric model in which the two mode-entangled (i.e. intraparticle
entangled) spin states of a single neutron are separated in space when they
interact with the grating accurately predicts the measured SESANS signal, which
is independent of the wave packet width.",2309.03987v2
2023-02-06,Accurate calculation of gravitational wave memory,"Gravitational wave memory is an important prediction of general relativity.
The detection of the gravitational wave memory can be used to test general
relativity and to deduce the property of the gravitational wave source.
Quantitative model is important for such detection and signal interpretation.
Previous works on gravitational wave memory always use the energy flux of
gravitational wave to calculate memory. Such relation between gravitational
wave energy and memory has only been validated for post-Newtonian
approximation. The result of numerical relativity about gravitational wave
memory is not confident yet. Accurately calculating memory is highly demanded.
Here we propose a new method to calculate the gravitational wave memory. This
method is based on Bondi-Metzner-Sachs theory. Consequently our method does not
need slow motion and weak field conditions for gravitational wave source. Our
new method can accurately calculate memory if the non-memory waveform is known.
As an example, we combine our method with matured numerical relativity result
about non-memory waveform for binary black hole coalescence. We calculate the
waveform for memory which can be used to aid memory detection and gravitational
wave source understanding. Our calculation result confirms preliminary
numerical relativity result about memory. We find out the dependence of the
memory amplitude to the mass ratio and the spins of the two spin aligned black
holes.",2302.02642v1
2019-01-30,Transverse waves in coronal flux tubes with thick boundaries: The effect of longitudinal flows,"Observations show that transverse magnetohydrodynamic (MHD) waves and flows
are often simultaneously present in magnetic loops of the solar corona. The
waves are resonantly damped in the Alfv\'en continuum because of plasma and/or
magnetic field nonuniformity across the loop. The resonant damping is relevant
in the context of coronal heating, since it provides a mechanism to cascade
energy down to the dissipative scales. It has been theoretically shown that the
presence of flow affects the waves propagation and damping, but most of the
studies rely on the unjustified assumption that the transverse nonuniformity is
confined to a boundary layer much thinner than the radius of the loop. Here we
present a semi-analytic technique to explore the effect of flow on resonant MHD
waves in coronal flux tubes with thick nonuniform boundaries. We extend a
published method, which was originally developed for a static plasma, in order
to incorporate the effect of flow. We allowed the flow velocity to continuously
vary within the nonuniform boundary from the internal velocity to the external
velocity. The analytic part of the method is based on expressing the wave
perturbations in the thick nonuniform boundary of the loop as a Frobenius
series that contains a singular term accounting for the Alfv\'en resonance,
while the numerical part of the method consists of solving iteratively the
transcendental dispersion relation together with the equation for the Alfv\'en
resonance position. As an application of this method, we investigated the
impact of flow on the phase velocity and resonant damping length of MHD kink
waves. We consistently recover results in the thin boundary approximation
obtained in previous studies. We have extended those results to the case of
thick boundaries. We also explored the error associated with the use of the
thin boundary approximation beyond its regime of applicability.",1901.10785v1
2014-04-29,"Comprehensive Amplitude Analysis of $γγ\rightarrow π^+π^-, π^0π^0$ and $\overline{K} K$ below 1.5 GeV","In this paper we perform an amplitude analysis of essentially all published
pion and kaon pair production data from two photon collisions below 1.5 GeV.
This includes all the high statistics results from Belle, as well as older data
from Mark II at SLAC, CELLO at DESY, Crystal Ball at SLAC. The purpose of this
analysis is to provide as close to a model-independent determination of the
$\gamma\gamma$ to meson pair amplitudes as possible. Having data with limited
angular coverage, typically $|\cos \theta| < 0.6-0.8$, and no polarization
information for reactions in which spin is an essential complication, the
determination of the underlying amplitudes might appear an intractable problem.
However, imposing the basic constraints required by analyticity, unitarity, and
crossing-symmetry makes up for the experimentally missing information.
  Final state interactions among the meson pairs are critical to this analysis.
To fix these, we include the latest $\pi\pi\to\pi\pi$, ${\overline K}K$
scattering amplitudes given by dispersive analyses, supplemented in the
${\overline K}K$ threshold region by the recent precision Dalitz plot analysis
from BaBar. With these hadronic amplitudes built into unitarity, we can
constrain the overall description of $\gamma\gamma\to\pi\pi$ and
$\overline{K}K$ datasets, both integrated and differential cross-sections,
including the high statistics charged and neutral pion, as well as $K_sK_s$
data from Belle. Since this analysis invokes coupled hadronic channels, having
data on both $\gamma\gamma\to\pi\pi$ and $\overline{K}K$ reduces the solution
space to essentially a single form. We present the partial wave amplitudes,
show how well they fit all the available data, and give the two photon
couplings of scalar and tensor resonances that appear. These partial waves are
important inputs into forthcoming dispersive calculations of hadronic
light-by-light scattering.",1404.7524v2
2021-12-31,Boltzmann Meets Lorentz: A Surrogate Model for Black Hole Echoes,"The existence of black hole horizons has not been strictly proven
observationally, and indeed it may not be possible to do so. However,
alternatives may be established by the observation of gravitational wave echoes
that probe possible near-horizon structure. These echoes are proposed to be
generated in exotic compact objects that are horizonless and feature a
partially reflecting ""wall"" inside their light rings, creating a cavity in
which gravitational perturbations may echo, while leaking out through the
angular momentum barrier with each pass. The characteristic signature of echoes
is a comb of nearly evenly spaced spectral resonances. While approximately
true, deviations from this simple picture can lead to severe observational
signal losses. In this paper, we explore such subtleties with the latest
results for echo sourcing and geometry. A physically motivated echo model is
then developed as a sum over Lorentzian spectral lines, parametrized by
functions of the horizon frame frequency and the size of the cavity. Our final
spectrum is a function of only the mass and spin of the black hole, as well as
the UV scale of the near-horizon physics. We then apply this model in a search
for echoes in the gravitational wave event with the loudest ringdown signal in
LIGO/Virgo, i.e. GW190521. We interpret our findings as a measurement of the
fractional energy in post-merger echoes equal to $E_{echoes} / E_{GR} = 8.9 \pm
4.5\%$, where the uncertainty range represents the 90% credible region. The
robustness of this result is tested against noise backgrounds and simulated
injections, and we find that a signal persists through modifications to the
model and changes in the data search.",2201.00027v1
2002-05-23,"Creation of nonlocal spin-entangled electrons via Andreev tunneling, Coulomb blockade and resonant transport","We discuss several scenarios for the creation of nonlocal spin-entangled
electrons which provide a source of electronic Einstein-Podolsky-Rosen (EPR)
pairs. The central idea is to exploit the spin correlations naturally present
in superconductors in form of Cooper pairs. We show that nonlocal
spin-entanglement in form of an effective Heisenberg spin interaction is
induced between electron spins residing on two quantum dots with no direct
coupling between them but each of them being tunnel-coupled to the same
superconductor. We then discuss a nonequilibrium setup where mobile and
nonlocal spin-entanglement can be created by coherent injection of two
electrons in an Andreev tunneling process into two spatially separated quantum
dots and subsequently into two Fermi-liquid leads. The current for injecting
two spin-entangled electrons into different leads shows a resonance whereas
tunneling via the same dot into the same lead is suppressed by the Coulomb
blockade effect of the quantum dots. The Aharonov-Bohm oscillations in the
current are shown to contain h/e and h/2e periods. Finally we discuss a
structure consisting of a superconductor weakly coupled to two separate
Luttinger liquid leads. We show that strong correlations again suppress the
coherent subsequent tunneling of two electrons into the same lead, thus
generating again nonlocal spin-entangled electrons.",0205484v1
2011-01-04,Universal Spin Transport in a Strongly Interacting Fermi Gas,"Transport of fermions is central in many fields of physics. Electron
transport runs modern technology, defining states of matter such as
superconductors and insulators, and electron spin, rather than charge, is being
explored as a new carrier of information [1]. Neutrino transport energizes
supernova explosions following the collapse of a dying star [2], and
hydrodynamic transport of the quark-gluon plasma governed the expansion of the
early Universe [3]. However, our understanding of non-equilibrium dynamics in
such strongly interacting fermionic matter is still limited. Ultracold gases of
fermionic atoms realize a pristine model for such systems and can be studied in
real time with the precision of atomic physics [4, 5]. It has been established
that even above the superfluid transition such gases flow as an almost perfect
fluid with very low viscosity [3, 6] when interactions are tuned to a
scattering resonance. However, here we show that spin currents, as opposed to
mass currents, are maximally damped, and that interactions can be strong enough
to reverse spin currents, with opposite spin components reflecting off each
other. We determine the spin drag coeffcient, the spin diffusivity, and the
spin susceptibility, as a function of temperature on resonance and show that
they obey universal laws at high temperatures. At low temperatures, the spin
diffusivity approaches a minimum value set by the ratio of the reduced Planck's
constant to the atomic mass. For repulsive interactions, our measurements
appear to exclude a metastable ferromagnetic state [7-9].",1101.0780v1
2012-10-09,Valley-spin blockade and spin resonance in carbon nanotubes,"Manipulation and readout of spin qubits in quantum dots made in III-V
materials successfully rely on Pauli blockade that forbids transitions between
spin-triplet and spin-singlet states. Quantum dots in group IV materials have
the advantage of avoiding decoherence from the hyperfine interaction by
purifying them with only zero-spin nuclei. Complications of group IV materials
arise from the valley degeneracies in the electronic bandstructure. These lead
to complicated multiplet states even for two-electron quantum dots thereby
significantly weakening the selection rules for Pauli blockade. Only recently
have spin qubits been realized in silicon devices where the valley degeneracy
is lifted by strain and spatial confinement. In carbon nanotubes Pauli blockade
can be observed by lifting valley degeneracy through disorder. In clean
nanotubes, quantum dots have to be made ultra-small to obtain a large energy
difference between the relevant multiplet states. Here we report on
low-disorder nanotubes and demonstrate Pauli blockade based on both valley and
spin selection rules. We exploit the bandgap of the nanotube to obtain a large
level spacing and thereby a robust blockade. Single-electron spin resonance is
detected using the blockade.",1210.2622v1
2015-07-28,Optical Control of Donor Spin Qubits in Silicon,"We show how to achieve optical, spin-selective transitions from the ground
state to excited orbital states of group-V donors (P, As, Sb, Bi) in silicon.
We consider two approaches based on either resonant, far-infrared (IR)
transitions of the neutral donor or resonant, near-IR excitonic transitions.
For far-IR light, we calculate the dipole matrix elements between the
valley-orbit and spin-orbit split states for all the goup-V donors using
effective mass theory. We then calculate the maximum rate and amount of
electron-nuclear spin-polarization achievable through optical pumping with
circularly polarized light. We find this approach is most promising for Bi
donors due to their large spin-orbit and valley-orbit interactions. Using
near-IR light, spin-selective excitation is possible for all the donors by
driving a two-photon $\Lambda$-transition from the ground state to higher
orbitals with even parity. We show that externally applied electric fields or
strain allow similar, spin-selective $\Lambda$-transition to odd-parity excited
states. We anticipate these results will be useful for future spectroscopic
investigations of donors, quantum control and state preparation of donor spin
qubits, and for developing a coherent interface between donor spin qubits and
single photons.",1507.07929v3
2018-11-02,Anatomy of electrical signals and dc-voltage lineshape in spin torque ferromagnetic resonance,"The electrical detection of spin torque ferromagnetic resonance (st-FMR) is
becoming a popular method for measuring the spin-Hall angle of heavy metals
(HM). However, various sensible analysis on the same material with either the
same or different experimental setups yielded different spin-Hall angles with
large discrepancy, indicating some missing ingredients in our current
understanding of st-FMR. Here we carry out a careful analysis of electrical
signals of the st-FMR in a HM/ferromagnet (HM/FM) bilayer with an arbitrary
magnetic anisotropy. The FM magnetization is driven by two radio-frequency (rf)
forces: the rf Oersted field generated by an applied rf electric current and
the so called rf spin-orbit torque from the spin current flowing
perpendicularly from the HM to the FM due to the spin-Hall effect. By using the
universal form of the dynamic susceptibility matrix of magnetic materials at
the st-FMR, the electrical signals originated from the anisotropic
magnetoresistance, anomalous Hall effect and inverse spin-Hall effect are
analysed and dc-voltage lineshape near the st-FMR are obtained.
Angle-dependence of dc-voltage is given for two setups. A way of experimentally
extracting the spin-Hall angle of a HM is proposed.",1811.00810v1
2017-05-03,Current driven second harmonic domain wall resonance in ferromagnetic metal/ nonmagnetic metal bilayer: a field-free method for spin Hall angle measurements,"We study the ac current-driven domain wall motion in bilayer ferromagnetic
metal (FM)/nonmagnetic metal (NM) nanowire. The solution of the modified
Landau-Lifshitz-Gilbert equation including all the spin transfer torques is
used to describe motion of the domain wall in presence of the spin Hall effect.
We show that the domain wall center has second harmonic frequency response in
addition to the known first harmonic excitation. In contrast to the
experimentally observed second harmonic response in harmonic Hall measurements
of spin-orbit torque in magnetic thin films, this second harmonic response
directly originates from spin-orbit torque driven domain wall dynamics. Based
on the spin current generated by domain wall dynamics, the longitudinal spin
motive force generated voltage across the length of the nanowire is determined.
The second harmonic response introduces additionally a new practical field-free
and all-electrical method to probe the effective spin Hall angle for FM/NM
bilayer structures that could be applied in experiments. Our results also
demonstrate the capability of utilizing FM/NM bilayer structure in domain wall
based spin torque signal generators and resonators.",1705.01355v5
2008-06-23,Spin-resolved quantum-dot resonance fluorescence,"In the quest for physically realizable quantum information science (QIS)
primitives, self-assembled quantum dots (QDs) serve a dual role as sources of
photonic (flying) qubits and traps for electron spin; the prototypical
stationary qubit. Here we demonstrate the first observation of spin-selective,
near background-free and transform-limited photon emission from a resonantly
driven QD transition. The hallmark of resonance fluorescence, i.e. the Mollow
triplet in the scattered photon spectrum when an optical transition is driven
resonantly, is presented as a natural way to spectrally isolate the photons of
interest from the original driving field. We go on to demonstrate that the
relative frequencies of the two spin-tagged photon states are tuned independent
of an applied magnetic field via the spin-selective dynamic Stark effect
induced by the very same driving laser. This demonstration enables the
realization of challenging QIS proposals such as heralded single photon
generation for linear optics quantum computing, spin-photon entanglement, and
dipolar interaction mediated quantum logic gates. From a spectroscopy
perspective, the spin-selective dynamic Stark effect tunes the QD spin-state
splitting in the ground and excited states independently, thus enabling
previously inaccessible regimes for controlled probing of mesoscopic spin
systems.",0806.3707v1
2021-01-27,Broad-band spectroscopy of a vanadyl porphyrin: a model electronuclear spin qudit,"We explore how to encode more than a qubit in vanadyl porphyrin molecules
hosting a electronic spin 1/2 coupled to a nuclear spin 7/2. The spin
Hamiltonian and its parameters, as well as the spin dynamics, have been
determined via a combination of electron paramagnetic resonance, heat capacity,
magnetization and on-chip magnetic spectroscopy experiments performed on single
crystals. We find low temperature spin coherence times of micro-seconds and
spin relaxation times longer than a second. For sufficiently strong magnetic
fields (B larger than 0.1 T, corresponding to resonance frequencies of 9 to 10
GHz) these properties make vanadyl porphyrin molecules suitable qubit
realizations. The presence of multiple equispaced nuclear spin levels then
merely provides 8 alternatives to define the 0 and 1 basis states. For lower
magnetic fields (below 0.1 T), and lower frequencies (smaller than 2 GHz), we
find spectroscopic signatures of a sizeable electronuclear entanglement. This
effect generates a larger set of allowed transitions between different
electronuclear spin states and removes their degeneracies. Under these
conditions, we show that each molecule fulfills the conditions to act as a
universal 4-qubit processor or, equivalently, as a d = 16 qudit. These findings
widen the catalogue of chemically designed systems able to implement
non-trivial quantum functionalities, such as quantum simulations and,
especially, quantum error correction at the molecular level.",2101.11650v1
2021-03-17,Spin injection efficiency at metallic interfaces probed by THz emission spectroscopy,"Terahertz (THz) spin-to-charge conversion has become an increasingly
important process for THz pulse generation and as a tool to probe ultrafast
spin interactions at magnetic interfaces. However, its relation to traditional,
steady state, ferromagnetic resonance techniques is poorly understood. Here we
investigate nanometric trilayers of Co/X/Pt (X=Ti, Au or Au0:85W0:15) as a
function of the 'X' layer thickness, where THz emission generated by the
inverse spin Hall effect is compared to the Gilbert damping of the
ferromagnetic resonance. Through the insertion of the 'X' layer we show that
the ultrafast spin current injected in the non-magnetic layer defines a direct
spin conductance, whereas the Gilbert damping leads to an effective spin
mixing-conductance of the trilayer. Importantly, we show that these two
parameters are connected to each other and that spin-memory losses can be
modeled via an effective Hamiltonian with Rashba fields. This work highlights
that magneto-circuits concepts can be successfully extended to ultrafast
spintronic devices, as well as enhancing the understanding of spin-to-charge
conversion processes through the complementarity between ultrafast THz
spectroscopy and steady state techniques.",2103.09557v1
2023-02-28,"Strong-coupling magnetophononics: Self-blocking, phonon-bitriplons, and spin-band engineering","Magnetophononics, the modulation of magnetic interactions by driving
infrared-active lattice excitations, is emerging as a key mechanism for the
ultrafast dynamical control of both semiclassical and quantum spin systems by
coherent light. We demonstrate that, in a quantum magnet with strong
spin-phonon coupling, resonances between the driven phonon and the spin
excitation frequencies exhibit an intrinsic self-blocking effect, whereby only
a fraction of the available laser power is absorbed by the phonon. Using the
quantum master equations governing the nonequilibrium steady states of the
coupled spin-lattice system, we show how self-blocking arises from the
self-consistent alteration of the resonance frequencies. We link this to the
appearance of mutually repelling collective spin-phonon states, which in the
regime of strong hybridization become composites of a phonon and two triplons.
We then identify the mechanism and optimal phonon frequencies by which to
control a global nonequilibrium renormalization of the lattice-driven spin
excitation spectrum and demonstrate that this effect should be observable in
ultrafast THz experiments on a number of known quantum magnetic materials.",2303.00125v1
2023-04-21,Magnetic properties of a spin-orbit entangled Jeff = 1/2 honeycomb lattice,"The interplay between spin-orbit coupling, anisotropic magnetic interaction,
frustration-induced quantum fluctuations and spin correlations can lead to
novel quantum states with exotic excitations in rare-earth-based quantum
magnets. Herein, we present the crystal structure, magnetization, electron spin
resonance (ESR), specific heat, and nuclear magnetic resonance (NMR)
experiments on the polycrystalline samples of Ba9Yb2Si6O24, in which Yb3+ ions
form a perfect honeycomb lattice without detectable anti-site disorder. The
magnetization data reveal antiferromagnetically coupled spin-orbit entangled
Jeff = 1/2 degrees of freedom of Yb3+ ions in the Kramers doublet state. The
ESR measurements reveal that the first excited Kramers doublet is 32.3(7) meV
above the ground state. The specific heat results suggest the absence of any
long-range magnetic order in the measured temperature range. Furthermore, the
29Si NMR results do not indicate any signature of magnetic ordering down to 1.6
K, and the spin-lattice relaxation rate reveals the presence of a field-induced
gap that is attributed to the Zeeman splitting of Kramers doublet state in this
quantum material. Our experiments detect neither spin freezing nor long-range
magnetic ordering down to 1.6 K. The current results suggest the presence of
short-range spin correlations in this spin-orbit entangled Jeff =1/2 rare-earth
magnet on a honeycomb lattice.",2304.10890v2
2023-07-30,Spin dynamics in ordered phases of anisotropic triangular-lattice antiferromagnet Cs2CoBr4,"We study spin dynamics of ordered phases of Cs2CoBr4 in a magnetic field
using electron spin resonance (ESR) technique and theoretical analysis. This
material hosts weakly interacting distorted-triangular-lattice planes of
spin-3/2 Co(2+) ions which can be viewed as spin chains coupled by frustrating
interactions. Strong single-ion anisotropy allows to describe the low-energy
spin dynamics of this system by an effective strongly anisotropic
pseudospin-1/2 model. Our ESR data show up to seven branches of magnetic
resonance in four magnetic phases arising due to subtle interplay of
frustration, low dimensionality and strong anisotropy. In particular, in the
low-field collinear stripe phase, the field evolution of modes lying below 200
GHz is described reasonably good by spectra of spin-1 and spin-0 quasiparticles
which we obtain using the bond-operator technique. These well-defined
excitations can be treated as conventional magnons and bound states of two
magnons, respectively. In contrast, numerous excitations lying above 200 GHz
are not captured by our theory due to pronounced one-dimensional correlations
inside spin chains which govern the spin dynamics at high enough energies. As
it was shown before, these modes can be most naturally interpreted as bound
states of domain walls in individual chains and their sequence resembles the
so-called ""Zeeman ladder"" in anisotropic Ising-like spin chains. Thus, Cs2CoBr4
is a system showing spin-dynamics in ordered state characteristic of both
two-dimensional and one-dimensional magnets.",2307.16251v1
2024-04-09,Excited-State Dynamics and Optically Detected Magnetic Resonance of Solid-State Spin Defects from First Principles,"Optically detected magnetic resonance (ODMR) is an efficient and reliable
method that enables initialization and readout of spin states through
spin-photon interface. In general, high quantum efficiency and large
spin-dependent photoluminescence (PL) contrast are desirable for reliable
quantum information readout. However, reliable prediction of the ODMR contrast
from first-principles requires accurate description of complex spin
polarization mechanisms of spin defects. These mechanisms often include
multiple radiative and nonradiative processes in particular intersystem
crossing (ISC) among multiple excited electronic states. In this work we
present our implementation of the first-principles ODMR contrast, by solving
kinetic master equation with calculated rates from ab initio electronic
structure methods then benchmark the implementation on the case of the
negatively-charged nitrogen vacancy (NV) center in diamond. We show the
importance of correct description of multi-reference electronic states for
accurate prediction of excitation energy, spin-orbit coupling, and the rate of
ISC. Moreover, we underscore the importance of pseudo Jahn-Teller effect for
the spin-orbit coupling, and the dynamical Jahn-Teller effect for
electron-phonon coupling, key factors determining ISC rates and ODMR contrast.
We show good agreement between our first-principles calculations and the
experimental ODMR contrast under magnetic field. We then demonstrate reliable
predictions of magnetic field direction, pump power, and microwave frequency
dependency, as important parameters for ODMR experiments. Our work clarifies
the important excited-state relaxation mechanisms determining ODMR contrast and
provides a predictive computational platform for spin polarization and optical
readout of solid-state quantum defects from first principles.",2404.05917v1
1999-07-10,Spin Tunneling and Phonon-assisted Relaxation in Mn12-acetate,"We present a comprehensive theory of the magnetization relaxation in a
Mn12-acetate crystal in the high-temperature regime (T>1 K), which is based on
phonon-assisted spin tunneling induced by quartic magnetic anisotropy and weak
transverse magnetic fields. The overall relaxation rate as function of the
longitudinal magnetic field is calculated and shown to agree well with
experimental data including all resonance peaks measured so far. The Lorentzian
shape of the resonances, which we obtain via a generalized master equation that
includes spin tunneling, is also in good agreement with recent data. We derive
a general formula for the tunnel splitting energy of these resonances. We show
that fourth-order diagonal terms in the Hamiltonian lead to satellite peaks. A
derivation of the effective linewidth of a resonance peak is given and shown to
agree well with experimental data. In addition, previously unknown spin-phonon
coupling constants are calculated explicitly. The values obtained for these
constants and for the sound velocity are also in good agreement with recent
data. We show that the spin relaxation in Mn12-acetate takes place via several
transition paths of comparable weight. These transition paths are expressed in
terms of intermediate relaxation times, which are calculated and which can be
tested experimentally.",9907154v2
2008-11-10,"Energy-scale phenomenology and pairing via resonant spin-charge motion in FeAs, CuO, heavy-fermion and other exotic superconductors","Muon spin relaxation ($\mu$SR) studies of the ""1111"" and ""122"" FeAs systems
have detected static magnetism with variably sized ordered moments in their
parent compounds. The phase diagrams of FeAs, CuO, organic BEDT,
A$_{3}$C$_{60}$ and heavy-fermion systems indicate competition between static
magnetism and superconductivity, associated with first-order phase transitions
at quantum phase boundaries. In both FeAs and CuO systems, the superfluid
density $n_{s}/m^{*}$ at $T \to 0$ exhibits a nearly linear scaling with
$T_{c}$. Analogous to the roton-minimum energy scaling with the lambda
transition temperature in superfluid $^{4}$He, clear scaling with $T_{c}$ was
also found for the energy of the magnetic resonance mode in cuprates,
(Ba,K)Fe$_{2}$As$_{2}$, CeCoIn$_{5}$ and CeCu$_{2}$Si$_{2}$, as well as the
energy of the superconducting coherence peak observed by angle resolved photo
emission (ARPES) in the cuprates near ($\pi$,0). Both the superfluid density
and the energy of these pair-non-breaking soft-mode excitations determine the
superconducting $T_{c}$ via phase fluctuations of condensed bosons. Combining
these observations and common dispersion relations of spin and charge
collective excitations in the cuprates, we propose a resonant spin charge
motion/coupling, ""traffic-light resonance,"" expected when the charge energy
scale $\epsilon_{F}$ becomes comparable to the spin fluctuation energy scale
$\hbar\omega_{SF}\sim J$, as the process which leads to pair formation in these
correlated electron superconductors.",0811.1546v2
2011-04-11,Discriminating Top-Antitop Resonances using Azimuthal Decay Correlations,"Top-antitop pairs produced in the decay of a new heavy resonance will exhibit
spin correlations that contain valuable coupling information. When the tops
decay, these correlations imprint themselves on the angular patterns of the
final quarks and leptons. While many approaches to the measurement of top spin
correlations are known, the most common ones require detailed kinematic
reconstructions and are insensitive to some important spin interference
effects. In particular, spin-1 resonances with mostly-vector or mostly-axial
couplings to top cannot be easily discriminated from one another without
appealing to mass-suppressed effects or to more model-dependent interference
with continuum Standard Model production. Here, we propose to probe the
structure of a resonance's couplings to tops by measuring the azimuthal angles
of the tops' decay products about the production axis. These angles exhibit
modulations which are typically O(0.1-1), and which by themselves allow for
discrimination of spin-0 from higher spins, measurement of the CP-phase for
spin-0, and measurement of the vector/axial composition for spins 1 and 2. For
relativistic tops, the azimuthal decay angles can be well-approximated without
detailed knowledge of the tops' velocities, and appear to be robust against
imperfect energy measurements and neutrino reconstructions. We illustrate this
point in the highly challenging dileptonic decay mode, which also exhibits the
largest modulations. We comment on the relevance of these observables for
testing axigluon-like models that explain the top quark A_FB anomaly at the
Tevatron, through direct production at the LHC.",1104.2043v2
2017-04-29,Spin-dependent constraints on blind spots for thermal singlino-higgsino dark matter with(out) light singlets,"The LUX experiment has recently set very strong constraints on
spin-independent interactions of WIMP with nuclei. These null results can be
accommodated in NMSSM provided that the effective spin-independent coupling of
the LSP to nucleons is suppressed. We investigate thermal relic abundance of
singlino-higgsino LSP in these so-called spin-independent blind spots and
derive current constraints and prospects for direct detection of spin-dependent
interactions of the LSP with nuclei providing strong constraints on parameter
space. We show that if the Higgs boson is the only light scalar the new LUX
constraints set a lower bound on the LSP mass of about 300 GeV except for a
small range around the half of $Z^0$ boson masses where resonant annihilation
via $Z^0$ exchange dominates. XENON1T will probe entire range of LSP masses
except for a tiny $Z^0$-resonant region that may be tested by the LZ
experiment. These conclusions apply to general singlet-doublet dark matter
annihilating dominantly to $t\bar{t}$. Presence of light singlet
(pseudo)scalars generically relaxes the constraints because new LSP (resonant
and non-resonant) annihilation channels become important. Even away from
resonant regions, the lower limit on the LSP mass from LUX is relaxed to about
250 GeV while XENON1T may not be sensitive to the LSP masses above about 400
GeV.",1705.00227v1
2021-05-14,Fast coherent control of an NV- spin ensemble using a KTaO3 dielectric resonator at cryogenic temperatures,"Microwave delivery to samples in a cryogenic environment can pose
experimental challenges such as restricting optical access, space constraints
and heat generation. Moreover, existing solutions that overcome various
experimental restrictions do not necessarily provide a large, homogeneous
oscillating magnetic field over macroscopic lengthscales, which is required for
control of spin ensembles or fast gate operations in scaled-up quantum
computing implementations. Here we show fast and coherent control of a
negatively charged nitrogen vacancy spin ensemble by taking advantage of the
high permittivity of a KTaO3 dielectric resonator at cryogenic temperatures. We
achieve Rabi frequencies of up to 48 MHz, with the total field-to-power
conversion ratio $C_{\rm P} = $ 9.66 mT/$\sqrt{\rm W}$ ($\approx191$
MHz/$\sqrt{\rm W}$). We use the nitrogen vacancy center spin ensemble to probe
the quality factor, the coherent enhancement, and the spatial distribution of
the magnetic field inside the diamond sample. The key advantages of the
dielectric resonator utilised in this work are: ease of assembly, in-situ
tuneability, a high magnetic field conversion efficiency, a low volume
footprint, and optical transparency. This makes KTaO3 dielectric resonators a
promising platform for the delivery of microwave fields for the control of
spins in various materials at cryogenic temperatures.",2105.06781v2
2022-11-21,In-situ amplification of spin echoes within a kinetic inductance parametric amplifier,"The use of superconducting micro-resonators in combination with
quantum-limited Josephson parametric amplifiers has in recent years lead to
more than four orders of magnitude improvement in the sensitivity of pulsed
Electron Spin Resonance (ESR) measurements. So far, the microwave resonators
and amplifiers have been designed as separate components, largely due to the
incompatibility of Josephson junction-based devices with even moderate magnetic
fields. This has led to complex spectrometers that operate under strict
environments, creating technical barriers for the widespread adoption of the
technique. Here we circumvent this issue by inductively coupling an ensemble of
spins directly to a weakly nonlinear microwave resonator, which is engineered
from a magnetic field-resilient thin superconducting film. We perform pulsed
ESR measurements with a $1$~pL effective mode volume and amplify the resulting
spin signal using the same device, ultimately achieving a sensitivity of $2.8
\times 10^3$ spins in a single-shot Hahn echo measurement at a temperature of
400 mK. We demonstrate the combined functionalities at fields as large as
254~mT, highlighting the technique's potential for application under more
conventional ESR operating conditions.",2211.11333v2
2023-05-25,Stability Improvement of Nuclear Magnetic Resonance Gyroscope with Self-Calibrating Parametric Magnetometer,"In this paper, we study the stability of nuclear magnetic resonance gyroscope
(NMRG), which employs Xe nuclear spins to measure inertial rotation rate. The
Xe spin polarization is sensed by an in-situ Rb-magnetometer. The
Rb-magnetometer works in a parametric oscillation mode (henceforth referred to
as the Rb parametric magnetometer, or Rb-PM), in which the Larmor frequency of
the Rb spins is modulated and the transverse components of Xe nuclear spin
polarization are measured. As the measurement output of the Rb-PM, the phase of
the Xe nuclear spin precession is eventually converted to the Xe nuclear
magnetic resonance (NMR) frequencies and the inertial rotation rate. Here we
provide a comprehensive study of the NMR phase measured by the Rb-PM, and
analyze the influence of various control parameters, including the DC magnetic
field, the frequency and phase of the modulation field, and the Rb resonance
linewidth, on the stability of the NMR phase. Based on these analysis, we
propose and implement a self-calibrating method to compensate the NMR phase
drift during the Rb-PM measurement. With the self-calibrating Rb-PM, we
demonstrate a significant improvement of the bias stability of NMRG.",2305.15847v1
2010-02-09,Searching for gravitational waves emitted by binaries with spinning components,"In this thesis we consider the data analysis problem of detecting
gravitational waves emitted by inspiraling binary systems. Detection of
gravitational waves will open a new window on the Universe enabling direct
detection of systems such as binary black holes for the first time. In the
first Chapter we show how gravitational waves are derived from Einstein's
General theory of Relativity and discuss the emission of gravitational waves
from inspiraling binaries and how this radiation may be detected using laser
interferometers. Around two thirds of stars inhabit binary systems. As they
orbit each other they will emit both energy and angular momentum in the form of
gravitational waves which will inevitably lead to their inspiral and eventual
merger. To date, searches for gravitational waves emitted during the inspiral
of binary systems have concentrated on systems with non-spinning components. In
Chapter 2 we detail the first dedicated search for binaries consisting of
spinning stellar mass compact objects. We analysed 788 hours of data collected
during the third science run (S3) of the LIGO detectors, no detection of
gravitational waves was made and we set an upper limit on the rate of
coalescences of stellar mass binaries. The inspiral of stellar mass compact
objects into super massive black holes will radiate gravitational waves at
frequencies detectable by the planned space-based LISA mission. In Chapter 3 we
describe the development and testing of a computationally cheap method to
detect the loudest few extreme mass ratio inspiral events that LISA will be
sensitive to.",1002.1876v1
2023-08-07,Inhomogeneous high temperature melting and decoupling of charge density waves in spin-triplet superconductor UTe2,"Periodic spatial modulations of the superfluid density, or pair density
waves, have now been widely detected in unconventional superconductors, either
as the primary or the secondary states accompanying charge density waves.
Understanding how these density waves emerge, or conversely get suppressed by
external parameters, provides an important insight into their nature. Here we
use spectroscopic imaging scanning tunneling microscopy to study the evolution
of density waves in the heavy fermion spin-triplet superconductor UTe2 as a
function of temperature and magnetic field. We discover that charge
modulations, composed of three different wave vectors gradually weaken but
persist to a surprisingly high temperature T_CDW ~ 10-12 K. By tracking the
local amplitude of modulations, we find that these modulations become spatially
inhomogeneous, and form patches that shrink in size with higher temperature or
with applied magnetic field. Interestingly, one of the density wave vectors
along the mirror symmetry has a slightly different temperature onset, thus
revealing an unexpected decoupling of the three-component CDW state.
Importantly, T_CDW determined from our work matches closely to the temperature
scale believed to be related to magnetic fluctuations, providing the first
possible connection between density waves observed by surface probes and bulk
measurements. Combined with magnetic field sensitivity of the modulations, this
could point towards an important role of spin fluctuations or short-range
magnetic order in the formation of the primary charge density wave.",2308.03721v1
2001-10-12,On Rossby waves and vortices with differential rotation,"We present a simplified model for linearized perturbations in a fluid with
both differential rotation and differential vorticity. Without the latter the
model reduces to the classical Shearing Sheet used in the description of spiral
density waves in astrophysical disks. Without the former it reduces to the
$\beta$-plane approximation, used in the description of Rossby waves.
  Retaining both, our model allows one in general to discuss the coupling
between density waves and Rossby waves, resulting in what is known as the
``corotation resonance'' for density waves.
  Here we derive, as a first application of this model, the properties of
Rossby waves in a differentially rotating disk. We find that their propagation
is quenched by differential rotation: after a limited number of oscillations, a
Rossby wave collapses to a singular vortex, as fluid elements are sheared apart
by differential rotation. In a keplerian disk, this number of oscillations is
always lower than one. We also describe how, in a similar manner, a vortex is
sheared in a very short time.",0110298v1
2003-11-17,Wave damping by MHD turbulence and its effect upon cosmic ray propagation in the ISM,"Cosmic rays scatter off magnetic irregularities (Alfven waves) with which
they are resonant, that is waves of wavelength comparable to their gyroradii.
These waves may be generated either by the cosmic rays themselves, if they
stream faster than the Alfven speed, or by sources of MHD turbulence. Waves
excited by streaming cosmic rays are ideally shaped for scattering, whereas the
scattering efficiency of MHD turbulence is severely diminished by its
anisotropy. We show that MHD turbulence has an indirect effect on cosmic ray
propagation by acting as a damping mechanism for cosmic ray generated waves.
The hot (``coronal'') phase of the interstellar medium is the best candidate
location for cosmic ray confinement by scattering from self-generated waves. We
relate the streaming velocity of cosmic rays to the rate of turbulent
dissipation in this medium, for the case in which turbulent damping is the
dominant damping mechanism. We conclude that cosmic rays with up to 10^2 GeV
could not stream much faster than the Alfven speed, but that 10^6 GeV cosmic
rays would stream unimpeded by self-generated waves unless the coronal gas were
remarkably turbulence-free.",0311400v1
2001-09-25,Weak magnetohydrodynamic turbulence of magnetized plasma,"Weak turbulence of magnetohydrodynamic (MHD) waves in strongly magnetized
plasma is studied when the thermal pressure is less than the magnetic field
pressure. In this situation the main nonlinear mechanism is the resonance
scattering of fast magneto-acoustic and Alfvenic waves on slow magneto-acoustic
waves. As a result, the former waves serve as the high-frequency waves with
respect to the latter ones so that the total number of HF waves - an adiabatic
invariant - conserves additionally. In the weak turbulence regime this
invariant is shown to generate the Kolmogorov type spectrum with a constant
flux of HF waves towards large-scale region. In the short-wave region another
Kolmogorov spectrum can be realized with a constant energy flux. The explicit
angle dependences for both types of turbulent spectra are found for the
propagation angles close to the direction of a mean magnetic field.",0109066v1
2011-07-15,Adiabatic nonlinear waves with trapped particles: I. General formalism,"A Lagrangian formalism is developed for a general nondissipative
quasiperiodic nonlinear wave with trapped particles in collisionless plasma.
The adiabatic time-averaged Lagrangian density $\mcc{L}$ is expressed in terms
of the single-particle oscillation-center Hamiltonians; once those are found,
the complete set of geometrical-optics equations is derived without referring
to the Maxwell-Vlasov system. The number of trapped particles is assumed fixed;
in particular, those may reside close to the bottom of the wave trapping
potential, so they never become untrapped. Then their contributions to the wave
momentum and the energy flux depend mainly on the trapped-particle density, as
an independent parameter, and the phase velocity rather than on the wave
amplitude $a$ explicitly; hence, $\mcc{L}$ acquires $a$-independent terms.
Also, the wave action is generally not conserved, because it can be exchanged
with resonant oscillations of the trapped-particle density. The corresponding
modification of the wave envelope equation is found explicitly, and the new
action flow velocity is derived. Applications of these results are left to the
other two papers of the series, where specific problems are addressed
pertaining to properties and dynamics of waves with trapped particles.",1107.3071v2
2011-07-23,"Schrodinger's Hat: Electromagnetic, acoustic and quantum amplifiers via transformation optics","The advent of transformation optics and metamaterials has made possible
devices producing extreme effects on wave propagation. Here we give theoretical
designs for devices, Schr\""odinger hats, acting as invisible concentrators of
waves. These exist for any wave phenomenon modeled by either the Helmholtz or
Schr\""odinger equations, e.g., polarized waves in EM, pressure waves in
acoustics and matter waves in QM, and occupy one part of a parameter space
continuum of wave-manipulating structures which also contains standard
transformation optics based cloaks, resonant cloaks and cloaked sensors. For EM
and acoustic Schr\""odinger hats, the resulting centralized wave is a localized
excitation. In QM, the result is a new charged quasiparticle, a \emph{quasmon},
which causes conditional probabilistic illusions. We discuss possible solid
state implementations.",1107.4685v1
2013-12-23,Tunable lattice Induced Opacity in atom-lattice interaction,"A lattice-induced opacity is identified in the scattering process of a
normally-incident matter wave from a two dimensional lattice of atoms. This
system can be treated as an analogue of a confinement induced resonance.
Specifically by modifying the s-wave scattering length between atoms in the
incident matter wave and the lattice-confined atoms, the transmission of the
matter wave can be tuned controllably from zero to one. Based on this, we
propose a possible scheme for a matter wave transistor. When the transmission
of the matter wave is tuned to zero, a matter wave cavity can be formed by
placing two such lattice planes of atoms parallel to one another. At higher
kinetic energies, the two dimensional lattice of atoms can also serve as a
matter wave beam splitter and a wave plate.",1312.6666v1
2014-04-08,Slow-light Airy wave packets and their active control via electromagnetically induced transparency,"We propose a scheme to generate (3+1)-dimensional slow-light Airy wave
packets in a resonant $\Lambda$-type three-level atomic gas via
electromagnetically induced transparency. We show that in the absence of
dispersion the Airy wave packets formed by a probe field consist of two Airy
wave packets accelerated in transverse directions and a longitudinal Gaussian
pulse with a constant propagating velocity lowered to $10^{-5}\,c$ ($c$ is the
light speed in vacuum). We also show that in the presence of dispersion it is
possible to generate another type of slow-light Airy wave packets consisting of
two Airy beams in transverse directions and an Airy wave packet in the
longitudinal direction. In this case, the longitudinal velocity of the Airy
wave packet can be further reduced during propagation. Additionally, we further
show that the transverse accelerations (or bending) of the both types of
slow-light Airy wave packets can be completely eliminated and the motional
trajectories of them can be actively manipulated and controlled by using a
Stern-Gerlach gradient magnetic field.",1404.2021v1
2015-03-08,Elastic Waves Scattering without Conversion in Metamaterials with Simultaneous Zero Indices for Longitudinal and Transverse waves,"We theoretically investigate elastic waves propagating in metamaterials with
simultaneous zero indices for both the longitudinal and transverse waves. With
scattering objects (here cylinders) present in the metamaterials slabs, while
the elastic waves can mostly transmit through the metamaterials slabs
perfectly, exhibiting the well-known cloaking effect of zero index
metamaterials, they nevertheless become totally blocked at resonances,
indicating strong elastic waves scattering by the objects in the cases.
However, despite the occurrence of the elastic waves scattering, there is,
counter-intuitively, no mode conversion between the longitudinal and transverse
waves in the process, completely in contrast with that in conventional elastic
media. A design of two-dimensional phononic crystal with these peculiar
properties is presented.",1503.02270v2
2015-10-27,Travelling wave solutions of multisymplectic discretizations of semi-linear wave equations,"How well do multisymplectic discretisations preserve travelling wave
solutions? To answer this question, the 5-point central difference scheme is
applied to the semi-linear wave equation. A travelling wave ansatz leads to an
ordinary difference equation, whose solutions correspond to the numerical
scheme and can be compared to travelling wave solutions of the corresponding
PDE. For a discontinuous nonlinearity the difference equation is solved
exactly. For continuous nonlinearities the difference equation is solved using
a Fourier series, and resonances that depend on the grid-size are revealed for
a smooth nonlinearity. In general, the infinite dimensional functional
equation, which must be solved to get the travelling wave solutions, is
intractable, but backward error analysis proves to be a powerful tool, as it
provides a way to study the solutions of the equation through a simple ODE that
describes the behavior to arbitrarily high order. A general framework for using
backward error analysis to analyze preservation of travelling waves for other
equations and discretisations is presented. Then, the advantages that
multisymplectic methods have over other methods are briefly highlighted.",1510.07765v1
2016-07-04,Corrugation of relativistic magnetized shock waves,"As a shock front interacts with turbulence, it develops corrugation which
induces outgoing wave modes in the downstream plasma. For a fast shock wave,
the incoming wave modes can either be fast magnetosonic waves originating from
downstream, outrunning the shock, or eigenmodes of the upstream plasma drifting
through the shock. Using linear perturbation theory in relativistic MHD, this
paper provides a general analysis of the corrugation of relativistic magnetized
fast shock waves resulting from their interaction with small amplitude
disturbances. Transfer functions characterizing the linear response for each of
the outgoing modes are calculated as a function of the magnetization of the
upstream medium and as a function of the nature of the incoming wave.
Interestingly, if the latter is an eigenmode of the upstream plasma, we find
that there exists a resonance at which the (linear) response of the shock
becomes large or even diverges. This result may have profound consequences on
the phenomenology of astrophysical relativistic magnetized shock waves.",1607.00768v1
2016-07-24,Nanoptera in a Period-2 Toda Chain,"We study asymptotic solutions to a singularly-perturbed, period-2 Toda
lattice and use exponential asymptotics to examine `nanoptera', which are
nonlocal solitary waves with constant-amplitude, exponentially small wave
trains. With this approach, we isolate the exponentially small,
constant-amplitude waves, and we elucidate the dynamics of these waves in terms
of the Stokes phenomenon. We find a simple asymptotic expression for the waves,
and we study configurations in which these waves vanish, producing localized
solitary-wave solutions. In the limit of small mass ratio, we derive a simple
anti-resonance condition for the manifestation these wave-free solutions.",1607.07065v2
2017-09-19,Dominant Resonance in Parametric Subharmonic Instability of Internal Waves,"Parametric Subharmonic Instability (PSI) is one of the most important
mechanisms that transfer energy from tidally-generated long internal waves to
short steep waves. Breaking of these short waves results in diapycnal mixing
through which oceanic abyssal stratification is maintained. It has long been
believed that PSI is strongest between a primary internal wave and perturbative
waves of half the frequency of the primary wave. Here, we rigorously show that
this is not the case. Specifically, we show that neither the initial growth
rate nor the maximum long-term amplification occur at the half frequency, and
demonstrate that the dominant subharmonic waves have much longer wavelengths
than previously thought.",1709.06250v2
2018-09-06,Confinement effects on gravity-capillary wave turbulence,"The statistical properties of a large number of weakly nonlinear waves can be
described in the framework of the Weak Turbulence Theory. The theory is based
on the hypothesis of an asymptotically large system. In experiments, the
systems have a finite size and the predictions of the theory may not apply
because of the presence of discrete modes rather than a continuum of free
waves. Our study focusses on the case of waves at the surface of water at
scales close to the gravity-capillarity crossover (of order 1~cm). Wave
turbulence has peculiar properties in this regime because 1D resonant
interactions can occur as shown by Aubourg \& Mordant. Here we investigate the
influence of the confinement on the properties of wave turbulence by reducing
gradually the size of our wave tank along one of its axis, the size in the
other direction being unchanged. We use space-time resolved profilometry to
reconstruct the deformed surface of water. We observe an original regime of
coexistence of weak wave turbulence along the length of the vessel and discrete
turbulence in the confined direction.",1809.01850v1
2018-09-13,"Scattering of scalar, electromagnetic and gravitational waves from binary systems","The direct detection of gravitational waves crowns decades of efforts in the
modelling of sources and of increasing detectors' sensitivity. With future
third-generation Earth-based detectors or space-based observatories,
gravitational-wave astronomy will be at its full bloom. Previously
brushed-aside questions on environmental or other systematic effects in the
generation and propagation of gravitational waves are now begging for a
systematic treatment. Here, we study how electromagnetic and gravitational
radiation is scattered by a binary system. Scattering cross-sections,
resonances and the effect of an impinging wave on a gravitational-bound binary
are worked out for the first time. The ratio between the scattered-wave
amplitude and the incident wave can be of order $10^{-5}$ for known pulsars,
bringing this into the realm of future gravitational-wave observatories. For
currently realistic distribution of compact-object binaries, the interaction
cross-section is too small to be of relevance.",1809.05108v1
2018-12-03,A piezo-metastructure with bistable circuit shunts for adaptive nonreciprocal wave transmission,"In this paper, we present a piezo-metastructure shunted with bistable
circuits to achieve adaptive nonreciprocal elastic wave transmission. Static
properties of the bistable circuit are first investigated, followed by
numerical investigation of wave transmission characteristics on the nonlinear
piezo-metastructure. Both the local-resonance bandgap and the bandgap
transmission phenomenon, also known as supratransmission, are explored and
investigated. By introducing circuit asymmetry, the supratransmission
thresholds, critical excitation amplitudes to enable bandgap transmission, are
found at different levels for the different wave transmission directions and
hence creating an excitation amplitude range within which nonreciprocal wave
transmission can be facilitated. Effect of the asymmetry factor on
nonreciprocity properties is subsequently analyzed and the trade-offs between
the forward transmission amplitude and the range of excitation with
nonreciprocity are identified. Additionally, it is demonstrated that wave
transmission characteristics of the proposed nonlinear piezo-metastructure can
be adaptively tuned by conveniently adjusting stable equilibria of the bistable
circuit. Lastly, the observed wave transmission properties are further
corroborated by experimental investigations. Overall, the results illustrate a
novel means to manipulate unidirectional elastic wave transmission using a
nonlinear piezo-metastructure.",1812.00517v1
2019-03-07,Three-wave interactions in magnetized warm-fluid plasmas: general theory with evaluable coupling coefficient,"Resonant three-wave coupling is an important mechanism via which waves
interact in a nonlinear medium. When the medium is a magnetized warm-fluid
plasma, a previously-unknown formula for the coupling coefficients is derived
by solving the fluid-Maxwell's equations to second order using multiscale
perturbative expansions. The formula is not only general but also evaluable,
whereby numerical values of the coupling coefficient can be determined for any
three resonantly interacting waves propagating at arbitrary angles. As one
example, coupling coefficient governing laser scattering is evaluated. In
conditions relevant to magnetized inertial confinement fusion experiments,
lasers scatter from magnetized plasma waves and the growth rates are modified
at oblique angles. As another example, coupling coefficient between two
Alfv\'en waves via a sound wave is evaluated. In conditions relevant to solar
corona, the decay of a parallel Alfv\'en wave only slightly prefers exact
backward geometry.",1903.02745v1
2021-08-20,Direct Evidence of a Dual Cascade in Gravitational Wave Turbulence,"We present the first direct numerical simulation of gravitational wave
turbulence. General relativity equations are solved numerically in a periodic
box with a diagonal metric tensor depending on two space coordinates only,
$g_{ij} \equiv g_{ii}(x,y,t) \delta_{ij}$, and with an additional small-scale
dissipative term. We limit ourselves to weak gravitational waves and to a
freely decaying turbulence. We find that an initial metric excitation at
intermediate wavenumber leads to a dual cascade of energy and wave action. When
the direct energy cascade reaches the dissipative scales, a transition is
observed in the temporal evolution of energy from a plateau to a power-law
decay, while the inverse cascade front continues to propagate toward low
wavenumbers. The wavenumber and frequency-wavenumber spectra are found to be
compatible with the theory of weak wave turbulence and the characteristic
time-scale of the dual cascade is that expected for four-wave resonant
interactions. The simulation reveals that an initially weak gravitational wave
turbulence tends to become strong as the inverse cascade of wave action
progresses with a selective amplification of the fluctuations $g_{11}$ and
$g_{22}$.",2108.09158v1
2019-07-08,Perfect conversion of a TM surface-wave into a TM leaky-wave by an isotropic periodic metasurface printed on a grounded dielectric slab,"This paper presents an exact solution for a perfect conversion of a
TM-polarized surface wave (SW) into a TM-polarized leaky-wave (LW) using a
reciprocal and lossless penetrable metasurface (MTS) characterized by a scalar
sheet impedance, located on a grounded slab. In contrast to known realizations
of leaky-wave antennas, the optimal surface reactance modulation which is found
here ensures the absence of evanescent higher-order modes of the field
Floquet-wave expansion near the radiating surface. Thus, all the energy carried
by the surface wave is used for launching the single inhomogeneous plane wave
into space without accumulation of reactive energy in the higher-order modes.
It is shown that the resulting penetrable MTS exhibits variation from an
inductive to a capacitive reactance passing through a resonance. The present
formulation complements a previous paper of the authors in which a perfect
conversion from TM-polarized SW to TE-polarized LW was found for impenetrable
boundary conditions. Here, the solution takes into account the grounded slab
dispersion and it is convenient for practical implementation.",1907.03646v2
2020-12-03,Low-dimensional chaos in the single wave model for self-consistent wave-particle Hamiltonian,"We analyze nonlinear aspects of the self-consistent wave-particle interaction
using Hamiltonian dynamics in the single wave model, where the wave is modified
due to the particle dynamics. This interaction plays an important role in the
emergence of plasma instabilities and turbulence. The simplest case, where one
particle (N = 1) is coupled with one wave (M = 1), is completely integrable,
and the nonlinear effects reduce to the wave potential pulsating while the
particle either remains trapped or circulates forever. On increasing the number
of particles (N = 2, M = 1), integrability is lost and chaos develops. Our
analyses identify the two standard ways for chaos to appear and grow (the
homoclinic tangle born from a separatrix, and the resonance overlap near an
elliptic fixed point). Moreover, a strong form of chaos occurs when the energy
is high enough for the wave amplitude to vanish occasionally.",2012.02139v5
2020-12-24,Experimental self-generation of axisymmetric internal wave super-harmonics,"In this paper, we present an experimental study of weakly non-linear
interaction of axisymmetric internal gravity waves in a resonant cavity,
supported by theoretical considerations. Contrary to plane waves in Cartesian
coordinates, for which self-interacting terms are null in a linear
stratifiation, the non-linear self-interaction of an internal wave mode in
axisymmetric geometry is found to be efficient at producing super-harmonics,
i.e. waves whose frequencies are integer multiples of the excitation frequency.
Due to the range of frequencies tested in our experiments, the first harmonic
frequency is below the cut-off imposed by the stratification so the lowest
harmonic created can always propagate. The study shows that the super-harmonic
wave field is a sum of standing waves satisfying both the dispersion relation
for internal waves and the boundary conditions imposed by the cavity walls,
while conserving the axisymmetry.",2012.13047v1
2021-11-29,Observations of rapidly growing whistler waves in front of space plasma shock,"Whistler mode wave is a fundamental perturbation of electromagnetic fields
and plasmas in various environments including planetary space, laboratory and
astrophysics. The origin and evolution of the waves are a long-standing
question due to the limited instrumental capability in resolving highly
variable plasma and electromagnetic fields. Here, we analyse data with the high
time resolution from the multi-scale magnetospheric spacecraft in the weak
magnetic environment (i.e., foreshock) enabling a relatively long gyro-period
of whistler mode wave. Moreover, we develop a novel approach to separate the
three-dimensional fluctuating electron velocity distributions from their
background, and have successfully captured the coherent resonance between
electrons and electromagnetic fields at high frequency, providing the resultant
growth rate of unstable whistler waves. Regarding the energy origin for the
waves, the ion distributions are found to also play crucial roles in
determining the eigenmode disturbances of fields and electrons. The
quantification of wave growth rate can significantly advance the understandings
of the wave evolution and the energy conversion with particles.",2111.14832v1
2023-01-20,Alfvén wave experiments with liquid rubidium in a pulsed magnetic field,"Magnetic fields are key ingredients for heating the solar corona to
temperatures of several million Kelvin. A particularly important region with
respect to this is the so-called magnetic canopy below the corona, where sound
and Alfv\'en waves have roughly the same speed and can, therefore, easily
transform into each other. We present the results of an Alfv\'en-wave
experiment with liquid rubidium carried out in a pulsed field of up to 63 T. At
the critical point of 54 T, where the speeds of Alfv\'en waves and sound
coincide, a new 4 kHz signal appears in addition to the externally excited 8
kHz torsional wave. This emergence of an Alfv\'en wave with a doubled period is
in agreement with the theoretical predictions of a parametric resonance between
the two wave types. We also present preliminary results from numerical
simulations of Alfv\'en and magneto-sonic waves using a compressible MHD code.",2301.08463v1
2006-12-01,Tidal dissipation within hot Jupiters: a new appraisal,"Eccentricity or obliquity tides have been proposed as the missing energy
source that may explain the anomalously large radius of some transiting ``hot
Jupiters''. To maintain a non-zero and large obliquity, it was argued that the
planets can be locked in a Cassini state, i.e. a resonance between spin and
orbital precessions. We compute the tidal heating within ``inflated'' close-in
giant planets with a non-zero eccentricity or obliquity. We further inspect
whether the spin of a ``hot Jupiter'' could have been trapped and maintained in
a Cassini state during its early despinning and migration. We estimate the
capture probability in a spin-orbit resonance between $\sim$ 0.5 AU (a distance
where tidal effects become significant) and 0.05 AU for a wide range of secular
orbital frequencies and amplitudes of gravitational perturbations. Numerical
simulations of the spin evolution are performed to explore the influence of
tidal despinning and migration processes on the resonance stability. We find
that tidal heating within a non-synchronous giant planet is about twice larger
than previous estimates based on the hypothesis of synchronization. Chances of
capture in a spin-orbit resonance are very good around 0.5 AU but they decrease
dramatically with the semi-major axis. Furthermore, even if captured, both
tidal despinning and migration processes cause the tidal torque to become large
enough that the obliquity ultimately leaves the resonance and switches to near
$0^{\circ}$. Locking a ``hot Jupiter'' in an isolated spin-orbit resonance is
unlikely at 0.05 AU but could be possible at larger distances. Another
mechanism is then required to maintain a large obliquity and create internal
heating through obliquity tides",0612044v1
2002-03-05,Study On Planar Whispering Gallery Dielectric Resonators. II. A Multiple-Band Device,"The basic theory underlying the realization of simple multiple-band
non-homogeneous dielectric resonators, whose spectral response is the overlap
of single-resonator frequency bands, is developed exploiting a general approach
discussed in the previous companion paper. The limit frequencies of the
proposed devices, given only by the dielectric properties of the involved
materials, can differ in principle by several decades. Experimental
confirmations have been obtained on a composite structure built up with teflon
and polyethylene; as predicted by the theory, the overall band includes
frequencies which range about from 20 GHz to more than 400 GHz, when high
frequency resonances are selectively excited. The localization of the higher
frequency radiation between the positive steps of the dielectric constant,
which is the basic properties of these non-homogeneous resonators, has been
experimentally verified by mapping the electromagnetic field intensity.
Possible applications of multiple-band Whispering Gallery dielectric resonators
are finally outlined.",0203010v1
2000-11-09,Dynamical analysis of the buildup process near resonance,"The time evolution of the buildup process inside a double-barrier system for
off-resonance incidence energies is studied by considering the analytic
solution of the time dependent Schr\""{o}dinger equation with cutoff plane wave
initial conditions. We show that the buildup process exhibits invariances under
arbitrary changes on the system parameters, which can be successfully described
by a simple and easy-to-use one-level formula. We find that the buildup of the
off-resonant probability density is characterized by an oscillatory pattern
modulated by the resonant case which governs the duration of the transient
regime. This is evidence that off-resonant and resonant tunneling are two
correlated processes, whose transient regime is characterized by the same
transient time constant of two lifetimes.",0011032v1
2008-05-26,Split ring resonator-coupled enhanced transmission through a single subwavelength aperture,"We report the enhanced transmission of electromagnetic waves through a single
subwavelength aperture by making use of the resonance behavior of a split ring
resonator (SRR) at microwave frequencies. By placing a single SRR at the
near-field of the aperture, strongly localized electromagnetic fields are
effectively coupled to the aperture with a radius that is twenty times smaller
than the resonance wavelength. We obtained 740-fold transmission enhancement by
exciting the electric resonance of SRR. A different coupling mechanism, through
the magnetic resonance of SRR, is also verified to yield enhanced transmission.
Good agreement is obtained between the microwave measurements and numerical
simulations.",0805.3907v1
2010-09-26,Optical and modal features of hemielliptic dielectric lenses,"Any dielectric lens has a finite closed boundary and therefore is, in fact,
an open dielectric resonator capable of supporting resonant modes whose
Q-factor depends of the lens parameters (size, shape, and material). The
hemielliptic lens, that is an essential building block of many mm-wave and THz
antennas, is not an exception: it supports the so-called halfbowtie (HBT)
resonances that can strongly affect performance of such antennas. In this paper
we illustrate the interplay between the optical and modal features in the
electromagnetic behaviour of hemielliptic lenses and highlight the drastic
influence of the HBT resonances on radiation characteristics of lens antennas.
We also discuss the difficulties associated with accurate description of the
resonant phenomena in compact-size hemielliptic lenses with conventional
techniques and provide recommendations on how to minimize the parasitic impact
of HBT resonances on the antenna performance.",1009.5114v2
2010-12-08,Elementary excitations in charge-tunable InGaAs quantum dots studied by resonant Raman and resonant photoluminescence spectroscopy,"We report on resonant optical spectroscopy of self-assembled InGaAs quantum
dots in which the number of electrons can accurately be tuned to N=0,1,2 by an
external gate voltage. Polarization, wave vector and magnetic field dependent
measurements enable us to clearly distinguish between resonant Raman and
resonant photoluminescence processes. The Raman spectra for N=1 and 2 electrons
considerably differ from each other. In particular, for N=2, the quantum-dot
He, the spectra exhibit both singlet and triplet transitions reflecting the
elementary many-particle interaction. Also the resonant photoluminescence
spectra are significantly changing by varying the number of electrons in the
QDs. For N=1 we observe strong polaronic effects which are suppressed for N=2.",1012.1762v1
2011-01-04,Plasmonically induced transparent magnetic resonance in a metallic metamaterial composed of asymmetric double bars,"We demonstrate that the trapped magnetic resonance mode can be induced in an
asymmetric double-bar structure for electromagnetic waves normally incident
onto the double-bar plane, which mode otherwise cannot be excited if the double
bars are equal in length. By adjusting the structural geometry, the trapped
magnetic resonance becomes transparent with little resonance absorption when it
happens in the dipolar resonance regime, a phenomenon so-called plasmonic
analogue of electromagnetically induced transparency. Accordingly, the
additional magnetic resonance by introducing asymmetry is explained as a result
of nonlinear plasmon coupling.",1101.0739v1
2011-08-08,Coupling Bright and Dark Plasmonic Lattice Resonances,"We demonstrate the coupling of bright and dark Surface Lattice Resonances
(SLRs), which are collective Fano resonances in 2D plasmonic crystals. As a
result of this coupling, a frequency stop-gap in the dispersion relation of
SLRs is observed. The different field symmetries of the low and high frequency
SLR bands lead to pronounced differences in their coupling to free space
radiation. Standing waves of very narrow spectral width compared to localized
surface plasmon resonances are formed at the high frequency band edge, while
subradiant damping onsets at the low frequency band edge leading the resonance
into darkness. We introduce a coupled oscillator analog to the plasmonic
crystal, which serves to elucidate the physics of the coupled plasmonic
resonances and to estimate very high quality factors (Q>700) for SLRs, which
are the highest known for any 2D plasmonic crystal.",1108.1620v1
2012-02-03,Asymptotics of the resonances for a continuously stratified layer,"Ultrasound wave propagation in a nonhomogeneous linearly elastic layer of
constant thickness is considered. The resonances for the corresponding acoustic
propagator are studied. It is shown that the distribution of the resonances
depends on the smoothness of the coefficients. Namely, if the coefficients have
jump discontinuities at the boundaries, then the resonances are asymptotically
distributed along a straight line parallel to the real axis on the unphysical
sheet of the complex frequency plane. In the contrary, if the coefficients are
continuous, then it is shown that the resonances are asymptotically distributed
along a logarithmic curve.
  The spacing between two successive resonances turns out to be sensitive to
articular cartilage degeneration. The application of the obtained results to
ultrasound testing of articular cartilage is discussed.",1202.0665v1
2012-02-14,Quantum resonant effects in the delta-kicked rotor revisited,"We review the theoretical model and experimental realization of the atom
optics $\delta-$kicked rotor (AOKR), a paradigm of classical and quantum chaos.
We have performed a number of experiments with an all-optical Bose-Einstein
condensate (BEC) in a periodic standing wave potential in an AOKR system. We
discuss results of the investigation of the phenomena of quantum resonances in
the AOKR. An interesting feature of the momentum distribution of the atoms
obtained as a result of short pulses of light, is the variance of the momentum
distribution or the kinetic energy $<p^{2}>/2m$ in units of the recoil energy
$E_{rec} = \hbar \omega_{rec}$. The energy of the system is examined as a
function of pulse period for a range of kicks that allow the observation of
quantum resonances. In particular we study the behavior of these resonances for
a large number of kicks. Higher order quantum resonant effects corresponding to
the fractional Talbot time of (1/4)$T_{T}$ and (1/5)$T_{T}$ for five and ten
kicks have been observed. Moreover, we describe the effect of the initial
momentum of the atoms on quantum resonances in the AOKR.",1202.3166v1
2012-10-01,Interplay between the 0+_2 resonance and the nonresonant continuum of the drip-line two-neutron halo nucleus 22C,"The breakup cross section (BUX) of 22C by 12C at 250 MeV/nucleon is evaluated
by the continuum-discretized coupled-channels method incorporating the
cluster-orbital shell model (COSM) wave functions. Contributions of the
low-lying 0+_2 and 2+_1 resonances predicted by COSM to the BUX are
investigated. The 2+_1 resonance gives a narrow peak in the BUX, as in usual
resonant reactions, whereas the 0+_2 resonant cross section has a peculiar
shape due to the coupling to the nonresonant continuum, i.e., the Fano effect.
By changing the scattering angle of 22C after the breakup, a variety of shapes
of the 0+_2 resonant cross sections is obtained. Mechanism of the appearance of
the sizable Fano effect in the breakup of 22C is discussed.",1210.0277v1
2013-03-15,Broadband second harmonic generation in whispering gallery mode resonators,"Optical frequency conversion processes in nonlinear materials are limited in
wavelength by the accessible phase matching and the required high pump powers.
In this letter, we report a novel broadband phase matching (PM) technique in
high quality factor (Q) whispering gallery mode (WGM) resonators made of
birefringent crystalline materials. This technique relies on two interacting
WGMs, one with constant and the other with spatially oscillating phase
velocity. Thus, phase matching occurs cyclically. The technique can be
implemented with a WGM resonator with its disk plane parallel to the optic axis
of the crystal. With a single beta barium borate (BBO) resonator in that
configuration, we experimentally demonstrated efficient second harmonic
generation (SHG) to harmonic wavelengths from 780 nm in the near infrared to
317 nm in the ultraviolet (UV). The observed SHG conversion efficiency is as
high as 4.6% (mW)-1. This broadband PM technique opens a new way for nonlinear
optics applications in WGM resonators. This work is also the first reported
continuous wave UV generation by direct SHG in a WGM resonator",1303.3814v1
2013-09-20,Implementation of a Quantum Metamaterial,"Manipulating the propagation of electromagnetic waves through sub-wavelength
sized artificial structures is the core function of metamaterials. Resonant
structures, such as split ring resonators, play the role of artificial ""atoms""
and shape the magnetic response. Superconducting metamaterials moved into the
spotlight for their very low ohmic losses and the possibility to tune their
resonance frequency by exploiting the Josephson inductance. Moreover, the
nonlinear nature of the Josephson inductance enables the fabrication of truly
artificial atoms. Arrays of such superconducting quantum two-level systems
(qubits) can be used for the implementation of a quantum metamaterial. Here, we
perform an experiment in which 20 superconducting flux qubits are embedded into
a single microwave resonator. The phase of the signal transmitted through the
resonator reveals the collective resonant coupling of up to 8 qubits. Quantum
circuits of many artificial atoms based on this proof-of-principle experiment
offer a wide range of prospects, from detecting single microwave photons to
phase switching, quantum birefringence and superradiant phase transitions.",1309.5268v1
2013-09-24,Double Fano resonances in a composite metamaterial possessing tripod plasmonic resonances,"By embedding four-rod resonators inside double-split ring resonators
superlattice, a planar composite metamaterial possessing tripod plasmonic
resonances is fabricated. Double Fano resonances are observed where a common
subradiant driven oscillator is coupled with two superradiant oscillators. As a
classical analogue of four-level tripod atomic system, the transmission
spectrum of the composite metamaterial exhibits a double Fano-based coherent
effect. Transfer of absorbed power between two superradiant oscillators is
controlled by manipulating two coupling strengths conjugated through the
polarization angle of a normally incident electromagnetic wave.",1309.6219v2
2014-01-28,Coherent versus incoherent excitation dynamics in dissipative many-body Rydberg systems,"We study the impact of dephasing on the excitation dynamics of a cloud of
ultracold two-level Rydberg atoms for both resonant and off-resonant laser
excitation, using the wave function Monte Carlo (MCWF) technique. We find that
while for resonant laser driving, dephasing mainly leads to an increase of the
Rydberg population and a decrease of the Mandel Q parameter, at off-resonant
driving strong dephasing toggles between direct excitation of pairs of atoms
and subsequent excitation of single atoms, respectively. These two excitation
mechanisms can be directly quantified via the pair correlation function, which
shows strong suppression of the two-photon resonance peak for strong dephasing.
Consequently, qualitatively different dynamics arise in the excitation
statistics for weak and strong dephasing in off-resonant excitation. Our
findings show that time-resolved excitation number measurements can serve as a
powerful tool to identify the dominating process in the system's excitation
dynamics.",1401.7260v1
2014-02-14,Multiresonance and chaotic behavior analysis for polarization in material modeled by multifrequency excitations duffing oscillator,"This paper considers nonlinear dynamics of polarization oscillations when
some materials when they are subjected to the action of an electromagnetic wave
modeled by multifrequency forced Duffing equation. Multiresonance and chaotic
behavior are analysed. For analysis of the case of resonance, the method of
multiple scales is used and it has been found from the equation of the
amplitudes for each of the possible resonance system. Possible resonances are
inter alia the resonances or sub superharmonic, the primary resonance and other
resonances called secondary. The phenomena of amplitude jump and hysteresis for
polarization were observed and analyzed. Finally, the study of chaotic behavior
for polarization was made by numerical simulation using the Runge- Kutta fourth
order.",1402.3420v1
2014-12-29,Perfect and broadband acoustic absorption by critical coupling,"We experimentally and analytically report broadband and narrowband perfect
absorption in two different acoustic waveguide-resonator geometries by the
mechanism of critical coupling. In the first geometry the resonator (a
Helmholtz resonator) is side-loaded to the waveguide and it has a moderate
quality factor. In the second geometry the resonator (a viscoelastic porous
plate) is in-line loaded and it contains two resonant modes with low quality
factor. The interplay between the energy leakage of the resonant modes into the
waveguide and the inherent losses of the system reveals a perfect and a
broadband nearly perfect absorption. The results shown in this work can
motivate relevant research for the design of broadband perfect absorbers in
other domains of wave physics.",1501.00191v1
2015-02-04,Hybridization and the origin of the Fano resonances in symmetric nanoparticle trimers,"We study the light scattering by plasmonic and dielectric symmetric trimers
to investigate the existence of polarization-independent Fano resonances.
Plasmonic hybridization theory is revealed to hide simple physics, and we
instead provide a simplified model for hybridization to derive a plasmonic
trimer's eigenmodes analytically. This approach is demonstrated to accurately
recreate full wave simulations of plasmonic trimers and their Fano resonances.
We are subsequently able to deduce the grounds for modal interference in
plasmonic trimers and the related formation of Fano resonances. However, by
taking advantage of the generality of our simplified hybridization approach, we
are also able to investigate the eigenmodes of all-dielectric trimers. We show
that bianisotropic coupling channels between high-index dielectric
nanoparticles are able to increase the capacity for Fano resonances, even at
normal incidence. We finally provide the first experimental measurements of
sharp, polarization-independent Fano resonances from a symmetric all-dielectric
trimer, with very good agreement to the predicted response from our simplified
hybridization theory.",1502.01308v2
2015-05-11,Creating and Probing Electron Whispering Gallery Modes in Graphene,"Designing high-finesse resonant cavities for electronic waves faces
challenges due to short electron coherence lengths in solids. Previous
approaches, e.g. the seminal nanometer-sized quantum corrals, depend on careful
positioning of adatoms at clean surfaces. Here we demonstrate an entirely
different approach, inspired by the peculiar acoustic phenomena in whispering
galleries. Taking advantage of graphene's unique properties, namely
gate-tunable light-like carriers, we create Whispering Gallery Mode (WGM)
resonators defined by circular pn-junctions, induced by a scanning tunneling
probe. We can tune the resonator size and the carrier concentration under the
probe in a back-gated graphene device over a wide range, independently and in
situ. The confined modes, revealed through characteristic resonances in the
tunneling spectrum, originate from Klein scattering at pn junction boundaries.
The WGM-type confinement and resonances are a new addition to the quantum
electron-optics toolbox, paving the way to real-world electronic lenses and
resonators.",1505.02732v1
2015-10-01,Imaging resonances in low-energy NO-He inelastic collisions,"In molecular collisions, resonances occur at specific energies where the
colliding particles temporarily form quasi-bound complexes, resulting in rapid
variations in the energy dependence of scattering cross sections.
Experimentally, it has proven challenging to observe such scattering
resonances, especially in differential cross sections. We report the
observation of resonance fingerprints in the state-to-state differential cross
sections for inelastic NO-He collisions in the 13 to 19 cm$^{-1}$ energy range
with 0.3 cm$^{-1}$ resolution. The observed structures were in excellent
agreement with quantum scattering calculations. They were analyzed by
separating the resonance contributions to the differential cross sections from
the background through a partitioning of the multichannel scattering matrix.
This revealed the partial wave composition of the resonances, and their
evolution during the collision.",1510.00299v1
2015-10-01,Cavity-coupled guided resonances with high quality factors in photonic crystal heterostructures,"We study the optical characteristics of a photonic crystal (PhC)
heterostructure cavity consisting of two-dimensional monolayer PhC, sandwiched
between two identical passive multilayers. In the range of stopband of the
multilayer, guided resonance of the sandwiched PhC are excited by the
evanescent waves of the multilayer stack and the quality factor of these
cavity-coupled guided resonances is about 10e6. The calculated field
distribution facilitates the distinction between the cavity defect modes and
the coupled guided resonances of the proposed design. The line shapes of the
resonances are explained using a theoretical model. Significant decrease in the
lasing threshold is observed for these resonant modes in comparison to the
defect modes. These results will find use in designing compact PhC-based
ultra-low threshold lasers and narrow band filters.",1510.00348v1
2016-08-23,Resonant Response in Mechanically Tunable Metasurface based on Crossed Metallic Gratings with Controllable Crossing Angle,"We report on a new class of mechanically tunable planar metamaterials
comprising resonating units formed by crossed metallic strip gratings. We
observe a resonant response in transmission spectra of a linearly polarized
wave passing through the system of crossed gratings. Each grating consists of
an array of parallel metallic strips located on the top of a dielectric
substrate. It is revealed that the resonant position appears to be dependent on
the angle of gratings crossing. It is found out both theoretically and
experimentally that the resonant shift on the frequency scale appears as a
result of increasing in the length of the resonating portion of the
parallelogram periodic cell formed by the crossed metallic strips with
decreasing crossing angle and the proposed design can be used in new types of
planar metamaterials and filters.",1608.06629v2
2017-07-31,Giant resonance and anomalous quality factor scaling in coupled resonator optical waveguides at the degenerate band edge,"We propose a novel scheme for enhancing the quality factor of coupled
resonators optical waveguides (CROWs) when operating near a degenerate band
edge (DBE). A DBE is a four-mode exceptional point of degeneracy (EPD)
occurring when four Bloch eigenmodes coalesce providing a resonance condition
with a giant enhancement in fields. We report an unprecedented scaling law of
quality factor of CROWs when operating at the DBE, even in the presence of
losses and structural perturbations. Remarkably, the Q factor of the proposed
CROW can be engineered to exceed that of a single ring resonator having a
diameter equal to the CROW length, hence having an overall strong area
reduction. The findings reported in this letter are critical for enhancing
fields amplitudes to giant levels and the Q factor of ring resonators and are
very beneficial for various applications including four wave mixing, Q
switching, lasers, and highly sensitive sensors.",1707.09737v1
2018-05-09,Solvable cubic resonant systems,"Weakly nonlinear analysis of resonant PDEs in recent literature has generated
a number of resonant systems for slow evolution of the normal mode amplitudes
that possess remarkable properties. Despite being infinite-dimensional
Hamiltonian systems with cubic nonlinearities in the equations of motion, these
resonant systems admit special analytic solutions, which furthermore display
periodic perfect energy returns to the initial configurations. Here, we
construct a very large class of resonant systems that shares these properties
that have so far been seen in specific examples emerging from a few standard
equations of mathematical physics (the Gross-Pitaevskii equation, nonlinear
wave equations in Anti-de Sitter spacetime). Our analysis provides an
additional conserved quantity for all of these systems, which has been
previously known for the resonant system of the two-dimensional
Gross-Pitaevskii equation, but not for any other cases.",1805.03634v2
2018-04-24,Silicon photonic filters based on cascaded Sagnac loop resonators,"We demonstrate advanced integrated photonic filters in silicon-on-insulator
(SOI) nanowires implemented by cascaded Sagnac loop reflector (CSLR)
resonators. We investigate mode splitting in these standing-wave (SW)
resonators and demonstrate its use for engineering the spectral profile of
on-chip photonic filters. By changing the reflectivity of the Sagnac loop
reflectors (SLRs) and the phase shifts along the connecting waveguides, we
tailor mode splitting in the CSLR resonators to achieve a wide range of filter
shapes for diverse applications including enhanced light trapping, flat-top
filtering, Q factor enhancement, and signal reshaping. We present the
theoretical designs and compare the CSLR resonators with three, four, and eight
SLRs fabricated in SOI. We achieve versatile filter shapes in the measured
transmission spectra via diverse mode splitting that agree well with theory.
This work confirms the effectiveness of using CSLR resonators as integrated
multi-functional SW filters for flexible spectral engineering.",1805.05405v1
2018-07-19,Clarifying the relationship between efficiency and resonance for flexible inertial swimmers,"We study a linear inviscid model of a passively flexible swimmer, calculating
its propulsive performance, eigenvalues, and eigenfunctions with an eye towards
clarifying the relationship between efficiency and resonance. The frequencies
of actuation and stiffness ratios we consider span a large range, while the
mass ratio is mostly fixed to a low value representative of swimmers. We
present results showing how the trailing edge deflection, thrust coefficient,
power coefficient, and efficiency vary in the stiffness-frequency plane. The
trailing edge deflection, thrust coefficient, and power coefficient show sharp
ridges of resonant behaviour for mid-to-high frequencies and stiffnesses,
whereas the efficiency does not show resonant behaviour anywhere. For low
frequencies and stiffnesses, the resonant peaks smear together and the
efficiency is high. In this region, flutter modes emerge, inducing travelling
wave kinematics which make the swimmer more efficient. We also consider the
effects of a finite Reynolds number in the form of streamwise drag. The drag
adds an offset to the net thrust produced by the swimmer, causing resonant
peaks to appear in the efficiency (as observed in experiments in the
literature).",1807.07499v1
2018-02-22,Electric quadrupole and magnetic dipole coupling in plasmonic nanoparticle arrays,"Collective resonances in plasmonic nanoparticle arrays with electric dipole
moment oriented along the lattice wave propagation are theoretically
investigated. The role of electric quadrupole (EQ) and magnetic dipole (MD)
moments of gold nanoparticles in the resonant features of the arrays is
analyzed. We perform both semi-analytical calculations of coupled multipole
equations and rigorous numerical simulations varying contributions of the
electric and magnetic multipoles by changing particle size and shape (spheres
and disks). The arrays in homogeneous and non-homogeneous environments are
considered. We find that even very weak non-resonant EQ and MD moments of a
single particle are significantly enhanced in the periodic lattice at the
wavelength of collective (lattice) resonance excitation. Importantly, we show
that in the infinite arrays, the EQ and MD moments of nanoparticles are coupled
and affect each other resonant contributions. We also demonstrate that at the
lattice-resonance wavelength, the enhanced EQ and MD moments have contributions
to reflection comparable to the dipole one resulting in a significant decrease
of reflection and providing the satisfaction of the generalized Kerker
condition for reflection suppression.",1802.07960v1
2019-02-26,Unconventional Cavity Optomechanics: Nonlinear Control of Phonons in the Acoustic Quantum Vacuum,"We study unconventional cavity optomechanics and the acoustic analogue of
radiation pressure to show the possibility of nonlinear coherent control of
phonons in the acoustic quantum vacuum. Specifically, we study systems where a
quantized optical field effectively modifies the frequency of an acoustic
resonator. We present a general method to enhance such a nonlinear interaction
by employing an intermediate qubit. Compared with conventional optomechanical
systems, the roles of mechanical and optical resonators are interchanged, and
the boundary condition of the phonon resonator can be modulated with an
ultrahigh optical frequency. These differences allow to test some quantum
effects with parameters which are far beyond the reach of conventional cavity
optomechanics. Based on this novel interaction form, we show that various
nonclassical quantum effects can be realized. Examples include an effective
method for modulating the resonance frequency of a phonon resonator (e.g., a
surface-acoustic-wave resonator), demonstrating mechanical parametric
amplification, and the dynamical Casimir effect of phonons originating from the
acoustic quantum vacuum. Our results demonstrate that unconventional
optomechanics offers a versatile hybrid platform for quantum engineering of
nonclassical phonon states in quantum acoustodynamics.",1902.09910v2
2019-06-28,Multiple scattering enabled superdirectivity from a subwavelength ensemble of resonators,"An ensemble of resonators arranged on a sub-wavelength scale is usually
considered as a bulk effective medium, known as a metamaterial, and can offer
unusual macroscopic properties. Here, we take a different approach and limit
ourselves to the study of only a few number of such elementary components and
demonstrate that it still offers uncommon opportunities. Typically, thanks to
the multiple scattering and the phase shift that the resonances offer, we
observe fields that vary at scales completely independent of the wavelength in
freespace. By smartly tuning the resonance frequencies, we can design at will
the complex current distribution in those resonators. This way, we design a
superdirective antenna, {\it ie.} an antenna that is surprisingly more
directive than its size would foreshadow. This approach is verified numerically
and experimentally in the context of microwaves, but this applies to any
wave-field where sub-wavelength resonators exist.",1906.12301v1
2016-12-23,"Parametric oscillation, frequency mixing and injection locking of strongly coupled nanomechanical resonator modes","We study locking phenomena of two strongly coupled, high-quality factor
nanomechanical resonator modes subject to a common parametric drive at a single
drive frequency. By controlled dielectric gradient forces we tune the resonance
frequencies of the flexural in-plane and out-of-plane oscillation of the high
stress silicon nitride string through their mutual avoided crossing. For the
case of the strong common parametric drive signal-idler generation via
parametric oscillation is observed, analogously to the framework of nonlinear
optical effects in an optical parametric oscillator. Frequency tuning of the
signal and idler resonances is demonstrated. When the resonance frequencies of
signal and idler get closer to each other, partial injection locking, injection
pulling and complete injection locking to half of the drive frequency occurs
depending on the pump strength. Furthermore, satellite resonances,
symmetrically off-set from signal and idler by their beat-note, are observed
which can be attributed to degenerate four-wave-mixing in the highly nonlinear
mechanical oscillations.",1612.07955v1
2017-02-22,Microplasma generation by slow microwave in an electromagnetically induced transparency-like metasurface,"Microplasma generation using microwaves in an electromagnetically induced
transparency (EIT)-like metasurface composed of two types of radiatively
coupled cut-wire resonators with slightly different resonance frequencies is
investigated. Microplasma is generated in either of the gaps of the cut-wire
resonators as a result of strong enhancement of the local electric field
associated with resonance and slow microwave effect. The threshold microwave
power for plasma ignition is found to reach a minimum at the EIT-like
transmission peak frequency, where the group index is maximized. A pump-probe
measurement of the metasurface reveals that the transmission properties can be
significantly varied by varying the properties of the generated microplasma
near the EIT-like transmission peak frequency and the resonance frequency. The
electron density of the microplasma is roughly estimated to be of order
$1\times 10^{10}\,\mathrm{cm}^{-3}$ for a pump power of $15.8\,\mathrm{W}$ by
comparing the measured transmission spectrum for the probe wave with the
numerically calculated spectrum. In the calculation, we assumed that the plasma
is uniformly generated in the resonator gap, that the electron temperature is
$2\,\mathrm{eV}$, and that the elastic scattering cross section is $20 \times
10^{-16}\,\mathrm{cm}^2$.",1702.06750v1
2018-04-22,Resonant Hamiltonian systems associated to the one-dimensional nonlinear Schrödinger equation with harmonic trapping,"We study two resonant Hamiltonian systems on the phase space $L^2(\mathbb{R}
\rightarrow \mathbb{C})$: the quintic one-dimensional continuous resonant
equation, and a cubic resonant system that has appeared in the literature as a
modified scattering limit for an NLS equation with cigar shaped trap. We prove
that these systems approximate the dynamics of the quintic and cubic
one-dimensional NLS with harmonic trapping in the small data regime on long
times scales. We then pursue a thorough study of the dynamics of the resonant
systems themselves. Our central finding is that these resonant equations fit
into a larger class of Hamiltonian systems that have many striking dynamical
features: non-trivial symmetries such as invariance under the Fourier transform
and the flow of the linear Scr\""odinger equation with harmonic trapping, a
robust wellposedness theory, including global wellposedness in $L^2$ and all
higher $L^2$ Sobolev spaces, and an infinite family of orthogonal, explicit
stationary wave solutions in the form of the Hermite functions.",1804.08190v1
2020-11-18,Coherence Resonance and Stochastic Resonance in an Excitable Semiconductor Superlattice,"Collective electron transport causes a weakly coupled semiconductor
superlattice under dc voltage bias to be an excitable system with $2N+2$
degrees of freedom: electron densities and fields at $N$ superlattice periods
plus the total current and the field at the injector. External noise of
sufficient amplitude induces regular current self-oscillations (coherence
resonance) in states that are stationary in the absence of noise. Numerical
simulations show that these oscillations are due to the repeated nucleation and
motion of charge dipole waves that form at the emitter when the current falls
below a critical value. At the critical current, the well-to-well tunneling
current intersects the contact load line. We have determined the
device-dependent critical current for the coherence resonance from experiments
and numerical simulations. We have also described through numerical simulations
how a coherence resonance triggers a stochastic resonance when its oscillation
mode becomes locked to a weak ac external voltage signal. Our results agree
with the experimental observations.",2011.09327v1
2017-04-19,Substrate Effect on Plasmonic Cube Dimers: Reversal of Optical Binding Force Induced by Strong Fano Resonance,"The behavior of Fano resonance and the reversal of near field optical binding
force of dimers over different substrates have not been studied so far. In this
work, we observe that if the closely located plasmonic cube homodimers over
glass or high permittivity dielectric substrate are illuminated with plane wave
polarized parallel to dimer axis, no reversal of optical binding force occurs.
But if we apply the same set-up over a plasmonic substrate, stable Fano
resonance occurs along with the reversal of near field binding force. It is
observed that during such Fano resonance stronger coupling occurs between the
dimers and plasmonic substrate along with the strong enhancement of the
substrate current. Such near field binding force reversals of plasmonic cube
dimers have been explained based on the observed unusual behavior of optical
Lorentz force during the induced stronger Fano resonance and the dipole-dipole
resonance. Although previously reported reversals of near field optical binding
forces were highly sensitive to particle size/shape (i.e. for heterodimers) and
inter-particle distance, our configuration provides much relaxation of those
parameters and hence should be verified experimentally with simpler
experimental set-ups.",1704.05633v1
2019-10-16,Relativistic Mean Motion Resonance,"Mean motion resonances are commonly seen in planetary systems, e.g., in the
formation of orbital structure of Jupiter's moons and the gaps in the rings of
Saturn. In this work we study their effects in fully relativistic systems. We
consider a model problem with two stellar mass black holes orbiting around a
supermassive black hole. By adopting a two time-scale expansion technique and
averaging over the fast varying orbital variables, we derive the effective
Hamiltonian for the slowly varying dynamical variables. The formalism is
illustrated with a n'_phi : n'_r : n_phi= 2:1:-2 resonance in Schwarzschild
spacetime, which naturally becomes the 3:2 resonance widely studied in the
Newtonian limit. We also derive the multi-body Hamiltonian in the
post-Newtonian regime, where the radial and azimuthal frequencies are different
because of the post-Newtonian precession. The capture and breaking conditions
for these relativistic mean motion resonances are also discussed. In
particular, pairs of stellar mass black holes surrounding the supermassive
black hole could be locked into resonances as they enter the LISA band, and
this would affect their gravitational wave waveforms.",1910.07337v1
2020-07-17,Giant resonant enhancement of optical binding of dielectric disks,"Two-parametric variation over the aspect ratio of each disk and distance
between disks gives rise to numerous events of avoided crossing of resonances
of individual disks. For these events the hybridized anti-bonding resonant
modes can acquire a morphology close to the Mie resonant mode with high orbital
momentum of equivalent sphere. The $Q$ factor of such resonance can exceed the
$Q$ factor of isolated disk by two orders in magnitude. We show that dual
incoherent counter propagating coaxial Bessel beams with power $1mW/\mu m^2$
with frequency resonant to such a anti-bonding modes result in unprecedented
optical binding forces up to decades of nano Newtons for silicon micron size
disks. We show also that a magnitude and sign of optical forces strongly depend
on the longitudinal wave vector of the Bessel beams.",2007.08721v1
2020-07-26,Unveiling shape resonances in H + HF collisions at cold energies,"Resonances are associated with the trapping of an intermolecular complex, and
are characterized by a series of quantum numbers such as the total angular
momentum and the parity, representative of a specific partial wave. Here we
show how at cold temperatures the rotational quenching of HF(j=1,2) with H is
strongly influenced by the presence of manifolds of resonances arising from the
combination of a single value of the orbital angular momentum with different
total angular momentum values. These resonances give rise up to a two-fold
increase in the thermal rate coefficient at the low temperatures characteristic
of the interstellar medium. Our results show that by selecting the relative
geometry of the reactants by alignment of the HF rotational angular momentum,
it is possible to decompose the resonance peak, disentangling the contribution
of different total angular momenta to the resonance.",2007.13088v1
2021-06-01,Effect of symmetry defect on the edge resonance of semi-infinite FGM plates,"The effect of asymmetric functionally graded material on the edge resonance
and the Fano resonance in semi-infinite FGM plates are reported in this work.
The edge resonance is weakened by the material perturbation and the complete
mode conversion is illustrated with incident $S_0$ mode. The Fano resonance
occurs on the reflected $A_0$ mode as a result of interference between the
resonance and direct scattering with incident $A_0$ mode. A hybrid analytical
model based on the collocation discretization and the modal decomposition of
the elastic field is developed to analyze the scattering properties of the
semi-infinite plates. The Fano line-shape is discussed in detail. The results
show that the Fano line shape is sensitive to the volume fraction, which is
beneficial for the quantitative guided wave application.",2106.00642v1
2022-01-27,Multi-photon Atom Interferometry via cavity-enhanced Bragg Diffraction,"We present a novel atom interferometer configuration that combines large
momentum transfer with the enhancement of an optical resonator for the purpose
of measuring gravitational strain in the horizontal directions. Using Bragg
diffraction and taking advantage of the optical gain provided by the resonator,
we achieve momentum transfer up to $8\hbar k$ with mW level optical power in a
cm-sized resonating waist. Importantly, our experiment uses an original
resonator design that allows for a large resonating beam waist and eliminates
the need to trap atoms in cavity modes. We demonstrate inertial sensitivity in
the horizontal direction by measuring the change in tilt of our resonator. This
result paves the way for future hybrid atom/optical gravitational wave
detectors. Furthermore, the versatility of our method extends to a wide range
of measurement geometries and atomic sources, opening up new avenues for the
realization of highly sensitive inertial atom sensors.",2201.11693v4
2022-04-19,Resonant and non-resonant integrated third order parametric down-conversion,"Third order parametric down-conversion describes a class of nonlinear
processes in which a pump photon can be down-converted into triplets of
photons. It has been identified as a source of non-classical light, with
capabilities beyond those offered by better-established processes such as
spontaneous four-wave mixing. Here we discuss the implementation of TOPDC in
integrated photonic systems. We derive equations for the rates of TOPDC in a
non-resonant (waveguide) and resonant (microring) platform, such that the
scaling with experimental parameters can be plainly seen. We find that
generally non-resonant platforms should be pursued for spontaneous TOPDC
(SpTOPDC), whereas resonant platforms are more suitable for stimulated TOPDC
(StTOPDC). We present a sample calculation for TOPDC rates in sample systems
with conservative and accessible parameters. We find that StTOPDC should be
observable with the current fabrication technology, and that with some progress
in the design of TOPDC platforms, integrated SpTOPDC too could be demonstrated
in the near term.",2204.09159v2
2022-10-27,Resonant modal approximation of time-domain elastic scattering from nano-bubbles in elastic materials,"This paper is devoted to establishing the resonant modal expansion of the
low-frequency part of the scattered field for acoustic bubbles embedded in
elastic materials in the time domain. Due to the nano-bubble with damping,
Minnaert resonance can be induced at certain discrete resonant frequencies,
which forms the fundamental basis of effectively constructing elastic
metamaterials via the composite material theory. There are two major
contributions in this work. First, we ansatz a special form of the density,
approximate the incident field with a finite number of modes, and then obtain
an expansion with a finite number of modes for the acoustic-elastic wave
scattering in the time-harmonic regime. Second, we show that the low-frequency
part of the scattered field in the time domain can be well approximated by
using the resonant modal expansion with sharp error estimates. Interestingly,
we find that the $0$-th mode is the main contribution to the resonant modal
expansion.",2210.15352v2
2022-12-12,Glueballs in Radiative $J/ψ$ Decays,"The scalar glueball is observed in a coupled-channel analysis of the $S$-wave
amplitude from BESIII data on radiative $J/\psi$ decays and further data. Ten
scalar isoscalar resonances were required to fit the data. Five of them were
interpreted as mainly-singlet, five as mainly-octet resonances in SU(3). The
yield of resonances showed a striking peak with properties expected from a
scalar glueball. The $D$ wave amplitude in the BESIII data on radiative
$J/\psi$ decays reveales a high-mass structure which can be described by a
single Breit-Wigner or by the sum of three $\phi\phi$ resonances interpreted as
tensor glueballs a long time ago. The structure - and further tensor resonances
observed in radiative $J/\psi$ decays - are tentatively interpreted as tensor
glueball. In $J/\psi$ decays into $\gamma\pi^0\pi^0\eta'$ several resonances
are reported. The possibility is discussed that the pseudoscalar glueball might
be hidden in these data.",2212.06214v1
2022-12-22,High-Q guided-mode resonance of a crossed grating with near-flat dispersion,"Guided-mode resonances in diffraction gratings are manifested as peaks (dips)
in reflection (transmission) spectra. Smaller resonance line widths (higher
Q-factors) ensure stronger light-matter interactions and are beneficial for
field-dependent physical processes. However, strong angular and spectral
dispersion are inherent to such high-Q resonances. We demonstrate that a class
of high-Q resonant modes (Q-factor >1000) exhibiting extraordinarily weak
dispersion can be excited in crossed gratings simultaneously with the modes
with well-known nearly linear dispersion. Furthermore, we show that the
polarization of the incoming light can be adjusted to engineer the dispersion
of these modes, and strong to near-flat dispersion or vice-versa can be
achieved by switching between two mutually orthogonal linear polarization
states. We introduce a semi-analytical model to explain the underlying physics
behind these observations and perform full-wave numerical simulations and
experiments to support our theoretical conjecture. The results presented here
will benefit all applications that rely on resonances in free-space-coupled
geometries.",2212.12059v1
2023-01-20,Renormalization view on resonance proliferation between many-body localized phases,"Topology and many-body localization (MBL) have opened new avenues for
preserving quantum information at finite energy density. Resonant
delocalization plays a crucial role in destabilizing these phenomena. In this
work, we study the statistical properties of many-body resonances in a
disordered interacting Ising model - which can host symmetry protected
topological order - using a Clifford circuit encoding of the real space
renormalization group which allows the resonant properties of the wave
functions to be efficiently characterized. Our findings show that both the
trivial and topologically ordered MBL phases remain stable to the resonances,
but in the vicinity of the transition between them localization is destabilized
by resonance proliferation. Diverging susceptibility towards the development of
an avalanche instability suggests an intervening ergodic phase. We are also
able to access the local integrals of motion in the MBL phases and identify the
topological edge-mode operators in the ordered phase. Our results have
important implications for the stability of MBL and phase transitions between
distinct MBL phases with and without symmetries.",2301.08738v3
2023-04-17,Identification and Mitigation of Conducting Package Losses for Quantum Superconducting Devices,"Low-loss superconducting rf devices are required when used for quantum
computation. Here, we present a series of measurements and simulations showing
that conducting losses in the packaging of our superconducting resonator
devices affect the maximum achievable internal quality factors (Qi) for a
series of thin-film Al quarter-wave resonators with fundamental resonant
frequencies varying between 4.9 and 5.8 GHz. By utilizing resonators with
different widths and gaps, different volumes of the stored electromagnetic
energy were sampled thus affecting Qi. When the backside of the sapphire
substrate of the resonator device is adhered to a Cu package with a conducting
silver glue, a monotonic decrease in the maximum achievable Qi is found as the
electromagnetic sampling volume is increased. This is a result of induced
currents in large surface resistance regions and dissipation underneath the
substrate. By placing a hole underneath the substrate and using superconducting
material for the package, we decrease the ohmic losses and increase the maximum
Qi for the larger size resonators.",2304.08629v2
2023-04-19,Characteristic modes of thick brane model: resonances and quasinormal modes,"In this work, we investigate the gravitational quasinormal modes (QNMs) and
the gravitational resonances of a thick brane model. We use the asymptotic
iteration and shooting methods to obtain the quasinormal frequencies (QNFs) of
the brane. On the other hand, we investigate the resonances and their evolution
numerically. The results show that the oscillations of the resonances equal (up
to numerical error) to the real parts of the QNFs, while the damping rates of
the resonances equal to the imaginary parts of the QNFs. The QNMs and
resonances, both of them can be regarded as the characteristic modes of the
thick brane, are closely related with each other. In addition, the lifetime of
these QNMs could be very long, perhaps they might be detected in future
accelerator or gravitational wave detector.",2304.09363v2
2023-07-25,Topological dissipative Kerr soliton combs in a valley photonic crystal resonator,"Topological phases have become an enabling role in exploiting new
applications of nonlinear optics in recent years. Here we theoretically propose
a valley photonic crystal resonator emulating topologically protected
dissipative Kerr soliton combs. It is shown that topological resonator modes
can be observed in the resonator. Moreover, we also simulate the dynamic
evolution of the topological resonator with the injection of a continuous-wave
pump laser. We find that the topological optical frequency combs evolve from
Turing rolls to chaotic states, and eventually into single soliton states. More
importantly, such dissipative Kerr soliton combs generated in the resonator are
inborn topologically protected, showing robustness against sharp bends and
structural disorders. Our design supporting topologically protected dissipative
Kerr soliton combs could be implemented experimentally in on-chip
nanofabricated photonic devices.",2307.13233v1
2023-08-03,Tuning of resonant doublets in coupled optical cavities,"The mode profile of a coupled optical cavity often exhibits a resonant
doublet, which arises from the strong coupling between its sub-cavities.
Traditional readout methods rely on setting fields of different frequencies to
be resonant in either sub-cavity, which is challenging in the case of strong
coupling. In this regime, the coupled cavity behaves as a single resonator, and
a field must be resonant in all its parts. Consequently, specialized sensing
schemes are necessary to control strongly coupled cavities. To address this
issue, we propose a novel technique for the relative measurement of the degrees
of freedom of a strongly coupled cavity. Our approach enables simultaneous
frequency stabilization and fine-tuning of frequency splitting in the resonant
doublet. Overall, our proposed technique offers a promising solution to control
the properties of coupled cavities, facilitating advanced applications in the
fields of gravitational-wave detection, quantum cavity optomechanics, and other
related areas.",2308.02574v1
2012-03-30,Using effective field theory to analyse low-energy Compton scattering data from protons and light nuclei,"Compton scattering provides important insight into the structure of the
nucleon. For photons up to about 300 MeV, it is parameterised by six dynamical
dipole polarisabilities which characterise the response of the nucleon to a
monochromatic photon of fixed frequency and multipolarity. Their zero-energy
limit yields the well-known static electric and magnetic dipole
polarisabilities \alpha and \beta, and the four dipole spin polarisabilities.
Chiral Effective Field Theory (ChiEFT) describes nucleon, deuteron and 3-He
Compton scattering, using consistent nuclear currents, rescattering and wave
functions. It can thus also be used to extract useful information on the
neutron amplitude from Compton scattering on light nuclei. We summarise past
work in ChiEFT on all of these reactions and compare with other theoretical
approaches. We also discuss all proton experiments up to about 400 MeV, as well
as the three modern elastic deuteron data sets, paying particular attention to
precision and accuracy of each set. Constraining the Delta(1232) parameters
from the resonance region, we then perform new fits to the proton data up to
omega(lab)=170 MeV, and a new fit to the deuteron data. After checking in each
case that a two-parameter fit is compatible with the respective Baldin sum
rules, we obtain, using the sum-rule constraints in a one-parameter fit,
\alpha=10.7\pm0.3(stat)\pm0.2(Baldin)\pm0.8(theory),
\beta=3.1\mp0.3(stat)\pm0.2(Baldin)\pm0.8(theory), for the proton
polarisabilities, and \alpha =10.9\pm 0.9(stat)\pm0.2(Baldin)\pm0.8(theory),
\beta =3.6\mp 0.9(stat)\pm0.2(Baldin)\pm0.8(theory), for the isoscalar
polarisabilities, each in units of 10^(-4) fm^3. We discuss plans for polarised
Compton scattering, their promise as tools to access spin polarisabilities, and
other future avenues for theoretical and experimental investigation.",1203.6834v2
2015-08-06,Steady state relativistic stellar dynamics around a massive black hole,"A massive black hole (MBH) consumes stars whose orbits evolve into the small
phase-space volume of unstable orbits, the ""loss-cone"", which take them
directly into the MBH, or close enough to interact strongly with it. The
resulting phenomena: tidal heating and tidal disruption, binary capture and
hyper-velocity star ejection, gravitational wave (GW) emission by inspiraling
compact remnants, or hydrodynamical interactions with an accretion disk, are of
interest as they can produce observable signatures and thereby reveal the
existence of the MBH, affect its mass and spin evolution, probe strong gravity,
and provide information on stars and gas near the MBH. The continuous loss of
stars and the processes that resupply them shape the central stellar
distribution. We investigate relativistic stellar dynamics near the loss-cone
of a non-spinning MBH in steady-state analytically and by Monte Carlo
simulations of the diffusion of the orbital parameters. These take into account
Newtonian mass precession due to enclosed stellar mass, in-plane precession due
to general relativity, dissipation by GW, uncorrelated two-body relaxation,
correlated resonant relaxation (RR) and adiabatic invariance due to secular
precession, using a rigorously derived description of correlated post-Newtonian
dynamics in the diffusion limit. We argue that general maximal entropy
considerations strongly constrain orbital diffusion in steady-state,
irrespective of the relaxation mechanism. We identify the exact phase-space
separatrix between plunges and inspirals, predict their steady-state rates, and
verify they are robust under a wide range of assumptions. We derive the
dependence of the rates on the mass of the MBH, show that the contribution of
RR is small, and discuss special cases where unquenched RR in restricted
volumes of phase-space may affect the steady-state substantially.",1508.01390v2
2015-11-16,Electric quadrupole interaction in cubic BCC alpha-Fe,"Moessbauer transmission spectra for the 14.41-keV resonant line in 57Fe have
been collected at room temperature by using 57Co(Rh) commercial source and
alpha-Fe strain-free single crystal as an absorber. The absorber was magnetized
to saturation in the absorber plane perpendicular to the gamma-ray beam axis
applying small external magnetic field. Spectra were collected for various
orientations of the magnetizing field, the latter lying close to the [110]
crystal plane. A positive electric quadrupole coupling constant was found
practically independent on the field orientation. One obtains the following
value Vzz=+1.61(4)x10^19 V/m^2 for the (average) principal component of the
electric field gradient (EFG) tensor under assumption that the EFG tensor is
axially symmetric and the principal axis is aligned with the magnetic hyperfine
field acting on the 57Fe nucleus. The nuclear spectroscopic electric quadrupole
moment for the first excited state of the 57Fe nucleus was adopted as +0.17 b.
Similar measurement was performed at room temperature using as-rolled
polycrystalline alpha-Fe foil of high purity in the zero external field.
Corresponding value for the principal component of the EFG was found as
Vzz=+1.92(4)x10^19 V/m^2. Hence, it seems that the origin of the EFG is
primarily due to the local (atomic) electronic wave function distortion caused
by the spin-orbit interaction between effective electronic spin S and
incompletely quenched electronic angular momentum L. It seems as well that the
lowest order term proportional to the product L.LAMBDA.S dominates, as no
direction dependence of the EFG principal component is seen. The lowest order
term is isotropic for a cubic symmetry as one has LAMBDA=lambda.1 for cubic
systems with the symbol 1 denoting unit operator and lambda being the coupling
parameter.",1511.04933v4
2016-01-04,Dynamics of a Qubit in a High-Impedance Transmission Line from a Bath Perspective,"We investigate quantum dynamics of a generic model of light-matter
interaction in the context of high impedance waveguides, focusing on the
behavior of the emitted photonic states, in the framework of the spin-boson
model Quantum quenches as well as scattering of an incident coherent pulse are
studied using two complementary methods. First, we develop an approximate
ansatz for the electromagnetic waves based on a single multimode coherent state
wavefunction; formally, this approach combines ideas from adiabatic
renormalization, the Born-Markov approximation, and input-output theory.
Second, we present numerically exact results for scattering of a weak intensity
pulse by using NRG calculations. NRG provides a benchmark for any linear
response property throughout the ultra-strong coupling regime. We find that in
a sudden quantum quench, the coherent state approach produces physical
artifacts, such as improper relaxation to the steady state. These previously
unnoticed problems are related to the simplified form of the ansatz that
generates spurious correlations within the bath. In the scattering problem, NRG
is used to find the transmission and reflection of a single photon, as well as
the inelastic scattering of that single photon. Simple analytical formulas are
established and tested against the NRG data that predict quantitatively the
transport coefficients for up to moderate environmental impedance. These
formulas resolve pending issues regarding the presence of inelastic losses in
the spin-boson model near absorption resonances, and could be used for
comparison to experiments in Josephson waveguide QED. Finally, the scattering
results using the coherent state wavefunction approach are compared favorably
to the NRG results for very weak incident intensity. We end our study by
presenting results at higher power where the response of the system is
nonlinear.",1601.00531v2
2017-11-21,Complementary views on electron spectra: From Fluctuation Diagnostics to real space correlations,"We study the relation between the microscopic properties of a many-body
system and the electron spectra, experimentally accessible by photoemission. In
a recent paper [Phys. Rev. Lett. 114, 236402 (2015)], we introduced the
""fluctuation diagnostics"" approach, to extract the dominant wave vector
dependent bosonic fluctuations from the electronic self-energy. Here, we first
reformulate the theory in terms of fermionic modes, to render its connection
with resonance valence bond (RVB) fluctuations more transparent. Secondly, by
using a large-U expansion, where U is the Coulomb interaction, we relate the
fluctuations to real space correlations. Therefore, it becomes possible to
study how electron spectra are related to charge, spin, superconductivity and
RVB-like real space correlations, broadening the analysis of an earlier work
[Phys. Rev. B 89, 245130 (2014)]. This formalism is applied to the pseudogap
physics of the two-dimensional Hubbard model, studied in the dynamical cluster
approximation. We perform calculations for embedded clusters with up to 32
sites, having three inequivalent K-points at the Fermi surface. We find that as
U is increased, correlation functions gradually attain values consistent with
an RVB state. This first happens for correlation functions involving the
antinodal point and gradually spreads to the nodal point along the Fermi
surface. Simultaneously a pseudogap opens up along the Fermi surface. We relate
this to a crossover from a Kondo-like state to an RVB-like localized cluster
state and to the presence of RVB and spin fluctuations. These changes are
caused by a strong momentum dependence in the cluster bath-couplings along the
Fermi surface. We also show, from a more algorithmic perspective, how the
time-consuming calculations in fluctuation diagnostics can be drastically
simplified.",1711.07671v1
2019-06-14,Optically and electrically excited intermediate electronic states in donor:acceptor based OLEDs,"Thermally activated delayed fluorescence (TADF) emitters consisting of donor
and acceptor molecules are potentially highly interesting for
electroluminescence (EL) applications. Their strong fluorescence emission is
considered to be due to reverse intersystem crossing (RISC), in which
energetically close triplet and singlet charge transfer (CT) states, also
called exciplex states, are involved. In order to distinguish between different
mechanisms and excited states involved, temperature-dependent spin-sensitive
measurements on organic light-emitting diodes (OLEDs) and thin films are
essential. In our work we apply continuous wave (cw) and time-resolved (tr)
photoluminescence (PL) spectroscopy as well as spin-sensitive EL and PL
detected magnetic resonance to films and OLED devices made of three different
donor:acceptor combinations. Our results clearly show that triplet exciplex
states are formed and contribute to delayed fluorescence (DF) via RISC in both
electrically driven OLEDs and optically excited films. In the same sample set
we also found molecular triplet excitons, which occurred only in PL experiments
under optical excitation and for some material systems only at low
temperatures. We conclude that in all investigated molecular systems exciplex
states formed at the donor:acceptor interface are responsible for TADF in OLEDs
with distinct activation energies. Molecular (local) triplet exciton states are
also detectable, but only under optical excitation, while they are not found in
OLEDs when excited states are generated electrically. We believe that the
weakly bound emissive exciplex states and the strongly bound non-emissive
molecular triplet excited states coexist in the TADF emitters, and it is
imperative to distinguish between optical and electrical generation paths as
they may involve different intermediate excited states.",1906.06073v3
2019-10-11,"Low-Damping Ferromagnetic Resonance in Electron-Beam Patterned, High-$Q$ Vanadium Tetracyanoethylene Magnon Cavities","Integrating patterned, low-loss magnetic materials into microwave devices and
circuits presents many challenges due to the specific conditions that are
required to grow ferrite materials, driving the need for flip-chip and other
indirect fabrication techniques. The low-loss ($\alpha = 3.98 \pm 0.22 \times
10^{-5}$), room-temperature ferrimagnetic coordination compound vanadium
tetracyanoethylene ($\mathrm{V[TCNE]}_x$) is a promising new material for these
applications that is potentially compatible with semiconductor processing. Here
we present the deposition, patterning, and characterization of
$\mathrm{V[TCNE]}_x$ thin films with lateral dimensions ranging from 1 micron
to several millimeters. We employ electron-beam lithography and liftoff using
an aluminum encapsulated poly(methyl methacrylate), poly(methyl
methacrylate-methacrylic acid) copolymer bilayer (PMMA/P(MMA-MAA)) on sapphire
and silicon. This process can be trivially extended to other common
semiconductor substrates. Films patterned via this method maintain low-loss
characteristics down to 25 microns with only a factor of 2 increase down to 5
microns. A rich structure of thickness and radially confined spin-wave modes
reveals the quality of the patterned films. Further fitting, simulation, and
analytic analysis provides an exchange stiffness, $A_{ex} = 2.2 \pm 0.5 \times
10^{-10}$ erg/cm, as well as insights into the mode character and surface spin
pinning. Below a micron, the deposition is non-conformal, which leads to
interesting and potentially useful changes in morphology. This work establishes
the versatility of $\mathrm{V[TCNE]}_x$ for applications requiring highly
coherent magnetic excitations ranging from microwave communication to quantum
information.",1910.05325v1
2020-10-06,Detecting resonant tidal excitations of Rossby modes in coalescing neutron-star binaries with third-generation gravitational-wave detectors,"Rossby modes (r-modes) of rotating neutron stars can be excited by the
gravitomagnetic forces in coalescing binary systems. The previous study by
Flanagan and Racine [Phys. Rev. D 75, 044001 (2007)] showed that this kind of
dynamical tide (DT) can induce phase shifts of 0.1 rad on gravitational
waveforms, which is detectable by third-generation (3G) detectors. In this
paper, we study the impact of this DT on measuring neutron-star parameters in
the era of 3G detectors. We incorporate two universal relations among neutron
star properties predicted by different equations of state: (i) the well-known
I-Love relation between momentum of inertia and (f-mode) tidal Love number, and
(ii) a relation between the r-mode overlap and tidal Love number, which is
newly explored in this paper. We find that r-mode DT will provide rich
information about slowly rotating neutron stars with frequency ranging from 10
to 100 Hz. For a binary neutron star system (with a signal-to-noise ratio
around 1500 in the Cosmic Explorer), the spin frequency of each individual
neutron star can be constrained to 6% (fractional error) in the best-case
scenario. The degeneracy between the Love numbers of individual neutron stars
is dramatically reduced: each individual Love number can be constrained to
around 20% in the best case, while the fractional error for both symmetric and
anti-symmetric Love numbers are reduced by factors of around 300. Furthermore,
DT also allows us to measure the spin inclination angles of the neutron stars,
to 0.09 rad in the best case, and thus place constraints on NS natal kicks and
supernova explosion models. Besides parameter estimation, we have also
developed a semi-analytic method that accurately describes detailed features of
the binary evolution that arise due to the DT.",2010.03066v2
2022-01-24,Selective Trapping of Hexagonally Warped Topological Surface States in a Triangular Quantum Corral,"The surface of a three-dimensional topological insulator (TI) hosts
two-dimensional massless Dirac fermions (DFs), the gapless and spin-helical
nature of which yields many exotic phenomena, such as the immunity of
topological surface states (TSS) to back-scattering. This leads to their high
transmission through surface defects or potential barriers. Quantum corrals,
previously elaborated on metal surfaces, can act as nanometer-sized electronic
resonators to trap Schr\""odinger electrons by quantum confinement. It is thus
intriguing, concerning their peculiar nature, to put the Dirac electrons of TSS
to the test in similar circumstances. Here, we report the behaviors of TSS in a
triangular quantum corral (TQC) fabricated by epitaxially growing Bi bilayer
nanostructures on the surfaces of Bi2Te3 films. Unlike a circular corral, the
TQC is supposed to be totally transparent for DFs. By mapping the electronic
structure of TSS inside TQCs through a low-temperature scanning tunneling
microscope in the real space, both the trapping and de-trapping behaviors of
the TSS electrons are observed. The selection rules are found to be governed by
the geometry and spin texture of the constant energy contour of TSS upon the
strong hexagonal warping in Bi2Te3. Careful analysis of the quantum
interference patterns of quasi-bound states yields the corresponding wave
vectors of trapped TSS, through which two trapping mechanisms favoring momenta
in different directions are uncovered. Our work indicates the extended nature
of TSS and elucidates the selection rules of the trapping of TSS in the
presence of a complicated surface state structure, giving insights into the
effective engineering of DFs in TIs.",2201.09440v1
1999-04-03,Chaos as a basis of new principle for detecting the gravitational waves,"A particular example of chaos can be conceived in the interaction of
non-linear oscillator with a harmonic gravitational wave. When we replace the
linear potential forces by the therm SIN(x), the type of solution becomes
subject to external perturbation. Although the perturbation produced by the
gravitational wave is weak the standard estimations allow to predict the
appearance of chaos at definite range of parameters. This qualitative change in
the character of motion immediately detects the fact of impact with
gravitational wave. Another advantage relates to a broad range of frequencies
so that the narrow resonance band is not required.",9904010v2
2003-09-11,A simple theory for the Raman spike,"The classical stimulated Raman scattering system describing resonant
interaction between two electromagnetic waves and a fast relaxing medium wave
is studied by introducting a systematic perturbation approach in powers of the
relaxation time. We separate amplitude and phase effects for these complex
fields. The analysis of the former shows the existence of a stagnation distance
after which monotonous energy transfer begins from one electromagnetic wave to
the other and this quantity is calculated. Concerning phase effects we give the
conditions for the formation of a Raman spike from an initial fast and large
phase jump in one of the waves. The spike evolution and width estimated from
the reduced model agree with the results from numerical simulations of the
original system.",0309038v1
2006-10-25,Multicomponent integrable wave equations I. Darboux-Dressing Transformation,"The Darboux-Dressing Transformations are applied to the Lax pair associated
to systems of coupled nonlinear wave equations in the case of boundary values
which are appropriate to both bright and dark soliton solutions. The general
formalism is set up and the relevant equations are explicitly solved. Several
instances of multicomponent wave equations of applicative interest, such as
vector nonlinear Schroedinger-type equations and three resonant wave equations
are considered.",0610061v1
2007-02-26,A possible mechanism of generation of extreme waves in shallow water,"We consider a mechanism of generation of huge waves by multi-soliton resonant
interactions. A non-stationary wave amplification phenomenon is found in some
exact solutions of the Kadomtsev-Petviashvili (KP) equation. The mechanism
proposed here explains the character of extreme waves and of those in Tsunami.",0702052v1
2003-03-20,Ray helicity: a geometric invariant for multi-dimensional resonant wave conversion,"For a multicomponent wave field propagating into a multidimensional
conversion region, the rays are shown to be helical, in general. For a
ray-based quantity to have a fundamental physical meaning it must be invariant
under two groups of transformations: congruence transformations (which shuffle
components of the multi-component wave field) and canonical transformations
(which act on the ray phase space). It is shown that for conversion between two
waves there is a new invariant not previously discussed: the intrinsic helicity
of the ray.",0303086v1
2004-02-13,Ion energy balance during fast wave heating in TORE SUPRA,"Direct coupling of the fast magnetosonic wave to the electrons has been
studied on the tokamak TORE SUPRA. Preliminary experiments were dedicated to
optimise the scenario for Fast Wave Electron Heating (FWEH) and Current Drive
(FWCD). In a first part, thermal kinetic and diamagnetic energy are compared
when fast wave is applied to the plasma in two different regimes: 1/ the
minority hydrogen heating scenario (ICRH), 2/ the direct electron damping.
Effects of ion resonant layers, marginally present in the plasma in the later
regime (FWEH), is then presented and discussed.",0402067v1
2006-02-14,Nonlinear interaction between three kinetic Alfvén waves,"Using Hall-MHD theory, we focus on the resonant interaction between three
kinetic Alfv\'{e}n waves. We thus derive three coupled equations which govern
this process. It turns out that these equations contain the same coupling
coefficient, directly showing that they satisfy the Manley-Rowe relations. The
coupling coefficient can be written in a comparatively very simple form, that
has not been deduced before. The decay rate, when a pump kinetic Alfv\'{e}n
wave decays into two similar Alfv\'{e}n waves, is therefore easily estimated
for plasmas of astrophysical interest.",0602090v1
2006-02-17,Surface wave generation and propagation on metallic subwavelength structures measured by far-field interferometry,"Transmission spectra of metallic films or membranes perforated by arrays of
subwavelength slits or holes have been widely interpreted as resonance
absorption by surface plasmon polaritons (SPPs). Alternative interpretations
involving evanescent waves diffracted on the surface have also been proposed.
These two approaches lead to divergent predictions for some surface wave
properties. Using far-field interferometry, we have carried out a series of
measurements on elementary one-dimensional (1-D) subwavelength structures with
the aim of testing key properties of the surface waves and comparing them to
predictions of these two points of view.",0602119v1
1999-12-13,Generation of continuous-wave THz radiation by use of quantum interference,"We propose a scheme for generation of continuous-wave THz radiation. The
scheme requires a medium where three discrete states in a $\Lambda $
configuration can be selected, with the THz-frequency transition between the
two lower metastable states. We consider the propagation of three-frequency
continuous-wave electromagnetic (e.m.) radiation through a $\Lambda $ medium.
Under resonant excitation, the medium absorption can be strongly reduced due to
quantum interference of transitions, while the nonlinear susceptibility is
enhanced. This leads to very efficient energy transfer between the e.m. waves
providing a possibility for THz generation. We demonstrate that the photon
conversion efficiency is approaching unity in this technique.",9912062v1
2007-04-28,Superconducting antenna for detection of gravitational waves,"Combining the principle of magnetic flux quantization inside a
superconducting loop and existence of rigid platforms (i.e., solids,
non-deformable under the action of gravitational waves) a design for
gravitational wave antenna is suggested. This design could yield a non-resonant
detector, with modest sizes and capability to generate detectable signals for
gravitational waves from astrophysical sources.",0704.3804v2
2009-04-16,Optical wave turbulence and condensation of light,"In an optical experiment, we report a wave turbulence regime that, starting
with weakly nonlinear waves with randomized phases, shows an inverse cascade of
photons towards the lowest wavenumbers. We show that the cascade is induced by
a six-wave resonant interaction process and is characterized by increasing
nonlinearity. At low wavenumbers the nonlinearity becomes strong and leads to
modulational instability developing into solitons, whose number is decreasing
further along the beam.",0904.2552v2
2009-07-10,Multicomponent integrable wave equations II: Soliton solutions,"The Darboux Dressing Transformations developed in our previous paper
(Multicomponent integrable wave equations I. Darboux-Dressing Transformation,
J. Phys. A: Math. Theor. 40, 961-977, 2007) are here applied to construct
soliton solutions for a class of boomeronic type equations. The vacuum (i.e.
vanishing) solution and the generic plane wave solution are both dressed to
yield one soliton solutions. The formulae are specialised to the particularly
interesting case of the resonant interaction of three waves, a well-known model
which is of boomeronic type. For this equation a novel solution which describes
three locked dark pulses (simulton) is introduced.",0907.1822v1
2009-12-21,Optical transition radiation in presence of acoustic waves,"Transition radiation from relativistic electrons is investigated in an
ultrasonic superlattice excited in a finite thickness plate. In the
quasi-classical approximation formulae are derived for the vector potential of
the electromagnetic field and for the spectral-angular distribution of the
radiation intensity. The acoustic waves generate new resonance peaks in the
spectral and angular distribution of the radiation intensity. The heights of
the peaks can be tuned by choosing the parameters of the acoustic wave.",0912.4111v2
2010-01-03,Interaction of linear waves and moving Josephson vortex lattices in layered superconductors,"A general phenomenological theory describing dynamics of Josephson vortices
coupled to wide class of linear waves in layered high-T$_c$ superconductors is
developed. The theory is based on hydrodynamic long wave approximation and
describes interaction of vortices with electromagnetic, electronic and phonon
degrees of freedom on an equal footing. In the limiting cases the proposed
theory degenerates to simple models considered earlier. In the framework of the
suggested model we undertook the numerical simulation of resistive state in
layered superconductors placed in external magnetic field and demonstrate
excitation of linear waves of various origin by a moving vortex lattice,
manifesting in existence of resonances on current-voltage characteristics.",1001.0302v1
2010-10-06,Additional Light Waves in Hydrodynamics and Holography,"We study the phenomenon of additional light waves (ALWs), observed in crystal
optics: two or more electromagnetic waves with the same polarization, but
different refractive index, propagate simultaneously in a isotropic medium. We
show that ALWs are common in relativistic hydrodynamics, and in particular in
strongly coupled systems that admit a dual gravitational description, where the
ALWs are dual to quasi normal modes in the AdS gravity. We study both the
transverse and the longitudinal light wave propagation. In the longitudinal
channel we find a transition between regimes with different number of excitonic
resonances which resembles the transition to standard optics observed in
crystals.",1010.1297v1
2012-02-26,Properties of ion-cyclotron waves in the open solar corona,"Remote observations of coronal holes have strongly implicated the resonant
interactions of ion-cyclotron waves with ions as a principal mechanism for
plasma heating and acceleration of the fast solar wind. In order to study these
waves, a WKB (Wentzel-Kramers-Brillouin) linear perturbation analysis is used
in the work frame of the collisionless multi-fluid model where we consider in
addition to the protons a second ion component made of alpha particles. We
consider a non-uniform background plasma describing a funnel region in the open
coronal holes and we use the ray tracing Hamiltonian type equations to compute
the ray path of the waves and the spatial variation of their properties.",1202.5742v1
2012-07-30,"""Gradient marker"" - a universal wave pattern in inhomogeneous continuum","Wave transport in a media with slow spatial gradient of its characteristics
is found to exhibit a universal wave pattern (""gradient marker"") in a vicinity
of the maxima/minima of the gradient. The pattern is common for optics, quantum
mechanics and any other propagation governed by the same wave equation. Derived
analytically in adiabatic limit, it has an elegantly simple yet nontrivial
single-cycle profile, which is found in perfect agreement with numerical
simulations for specific examples. We also found resonant states in continuum
in the case of quantum wells, and formulated criterium for their existence.",1207.6807v1
2013-02-13,Velocity selective trapping of atoms in a frequency-modulated standing laser wave,"The wave function of a moderately cold atom in a stationary near-resonant
standing light wave delocalizes very fast due to wave packet splitting.
However, we show that frequency modulation of the field may suppress packet
splitting for some atoms having specific velocities in a narrow range. These
atoms remain localized in a small space for a long time. We propose that in a
real experiment with cold atomic gas this effect may decrease the velocity
distribution of atoms (the field traps the atoms with such specific velocities
while all other atoms leave the field)",1302.2970v2
2013-05-25,Soliton interaction mediated by cascaded four wave mixing with dispersive waves,"We demonstrate that trapping of dispersive waves between two optical solitons
takes place when resonant scattering of the waves on the solitons leads to
nearly perfect reflections. The momentum transfer from the radiation to
solitons results in their mutual attraction and a subsequent collision. The
spectrum of the trapped radiation can either expand or shrink in the course of
the propagation, which is controlled by arranging either collision or
separation of the solitons.",1305.5909v1
2013-11-23,Enhanced propagation of photon density waves in random amplifying media,"We demonstrate enhanced wave-like character of diffuse photon density waves
(DPDW) in an amplifying random medium. The amplifying nature makes it
contingent to choose the wave solution that grows inside the amplifying medium,
and has a propagation vector pointing opposite to the growth direction. This
results in negative refraction of the DPDW at an absorbing-amplifying random
medium interface as well as the possibility of supporting ""anti""-surface-like
modes at the interface. A slab of amplifying random medium sandwiched between
two absorbing random media supports waveguide resonances that can be utilized
to extend the imaging capabilities of DPDW.",1311.5985v1
2016-01-30,Breather-to-soliton and rogue wave-to-soliton transitions in a resonant erbium-doped fiber system with higher-order effects,"Under investigation in this paper is the higherorder nonlinear Schrodinger
and Maxwell-Bloch (HNLSMB) system which describes the wave propagation in an
erbium-doped nonlinear fiber with higher-order effects including the
fourth-order dispersion and quintic nonKerr nonlinearity. The breather and
rogue wave (RW) solutions are shown that they can be converted into various
soliton solutions including the multipeak soliton, periodic wave, antidark
soliton, M-shaped soliton, and W-shaped soliton. In addition, under different
values of higher-order effect, the locus of the eigenvalues on the complex
plane which converts breathers or RWs into solitons is calculated.",1602.00077v1
2017-09-24,On the wave turbulence theory for stratified flows in the ocean,"After the pioneering work of Garrett and Munk, the statistics of oceanic
internal gravity waves has become a central subject of research in
oceanography. The time evolution of the spectral energy of internal waves in
the ocean can be described by a near-resonance wave turbulence equation, of
quantum Boltzmann type. In this work, we provide the first rigorous
mathematical study for the equation by showing the global existence and
uniqueness of strong solutions.",1709.08266v3
2017-11-26,Response solutions for wave equations with variable wave speed and periodic forcing,"We consider a model of nonlinear wave equations with periodically varying
wave speed and periodic external forcing. By imposing non-resonance conditions
on the frequency, we establish the existence of the response solutions (i.e.,
periodic solutions with the same frequency as the forcing) for such a model in
a Cantor set of asymptotically full measure. The proof relies on a
Lyapunov--Schmidt reduction together with the Nash--Moser iteration.",1711.09437v2
2017-05-05,Dykes for filtering ocean waves using c-shaped vertical cylinders,"The present study investigates a way to design dykes which can filter the
wavelengths of ocean surface waves. This offers the possibility to achieve a
structure that can attenuate waves associated with storm swell, without
affecting coastline in other conditions. Our approach is based on low frequency
resonances in metamaterials combined with Bragg frequencies for which waves
cannot propagate in periodic lattices.",1705.02132v1
2014-06-23,Global analysis of a model for capillary water waves in 2D,"In this paper we prove a global regularity result for a quadratic quasilinear
model associated to the water waves system with surface tension and no gravity
in dimension two (the capillary waves system). The model we consider here
retains most of the difficulties of the full capillary water waves system,
including the delicate time-resonance structure and modified scattering. It is
slightly simpler, however, at the technical level and our goal here is to
present our method in this simplified situation. The full system is the subject
of a forthcoming paper.",1406.6042v2
2017-06-25,Sub-wavelength focusing of acoustic waves in bubbly media,"The purpose of this paper is to investigate acoustic wave scattering by a
large number of bubbles in a liquid at frequencies near the Minnaert resonance
frequency. This bubbly media has been exploited in practice to obtain
super-focusing of acoustic waves. Using layer potential techniques we derive
the scattering function for a single spherical bubble excited by an incident
wave in the low frequency regime. We then derive the point scatter
approximation for multiple scattering by N bubbles. We describe several
numerical experiments based on the point scatterer approximation that
demonstrate the possibility of achieving super-focusing using bubbly media.",1706.08113v1
2020-11-24,Time Quasi-Periodic Traveling Gravity Water Waves in Infinite Depth,"We present the recent result [8] concerning the existence of quasi-periodic
in time traveling waves for the 2d pure gravity water waves system in infinite
depth. We provide the first existence result of quasi-periodic water waves
solutions bifurcating from a completely resonant elliptic fixed point. The
proof is based on a Nash-Moser scheme, Birkhoff normal form methods and
pseudo-differential calculus techniques. We deal with the combined problems of
small divisors and the fully-nonlinear nature of the equations.",2011.12794v1
2021-04-13,Magnetless Reflective Gyrotropic Spatial Isolator Metasurface,"We present the concept of a magnetless Reflective Gyrotropic Spatial Isolator
(RGSI) metasurface. This is a birefringent metasurface that reflects vertically
polarized incident waves into a horizontally polarized waves, and absorbs
horizontally polarized incident waves, hence providing isolation between the
two orthogonal polarization. We first synthesize the metasurface using surface
susceptibility-based Generalized Sheet Transition Conditions~(GSTCs). We then
propose a mirror-backed metaparticle implementation of this metasurface, where
transistor-loaded resonators provide the desired magnetless nonreciprocal
response. Finally, we demonstrate the metasurface by full-wave simulation
results. The proposed RGSI metasurface may be used in various electromagnetic
applications, and may also serve as a step towards more sophisticated
magnetless nonreciprocal metasurface systems.",2104.09300v1
2021-10-22,Wide elastic wave bandgap metamaterial with single phase constituent,"Accomplishing a wide elastic wave bandgap with single phase constituent is of
primary interest in developing phononic metamaterials. In the present article,
exploiting spatial periodicity, a single phase lattice is configured towards
achieving a large frequency bandgap in sonic range. Numerical simulations
reveal the presence of a comprehensive bandgap of 18 kHz in the 2 to 22 kHz
range with systematically localizing the same constituent material in the
lattice. Bloch wave modes unravel the involvement of dipole, monopole, and
quadrupole resonances for wide and connected bandgaps. The existence of salient
bandgaps is experimentally validated by analyzing the mechanical wave
transmission.",2110.11690v1
2008-06-09,On Electromagnetic Wave Interaction with Dense Resonant Atom Medium,"The excitation of atomic levels due to interaction with electromagnetic waves
became of interest in accelerator physics in relation to high efficiency charge
exchange injection into rings for high beam power applications. Usually, the
beam density is so small that its influence on the wave is completely
neglected. Here we consider the case of dense beams - the beam dimensions are
large as compared to light reflection length. This paper shows that the waves
can be trapped in the medium under these conditions. Moreover, the atoms with
induced dipole moments start to interact strongly with each other, leading to
possibility to create some atomic patterns when the medium is relatively cold.",0806.1526v1
2016-11-14,Shortcut to adiabatic control of soliton matter waves by tunable interaction,"We propose a method for shortcut to adiabatic control of soliton matter waves
in harmonic traps. The tunable interaction controlled by Feshbach resonance is
inversely designed to achieve fast compression of soliton matter waves but
within a short time, as compared to the conventional adiabatic compression.
These results pave the way to control the nonlinear dynamics for matter waves
and optical solitons by using shortcuts to adiabaticity.",1611.04371v1
2020-10-29,Mode Conversion and Period Doubling at Plasma-$β$ Unity in an Alfvén-Wave Experiment with Liquid Rubidium,"We report Alfv\'en-wave experiments with liquid rubidium at the Dresden High
Magnetic Field Laboratory (HLD). Reaching up to 63 T, the pulsed magnetic field
exceeds the critical value of 54 T at which the Alfv\'en speed becomes equal to
the sound speed (plasma-$\beta$ unity). At this threshold we observe a period
doubling of an applied 8 kHz CW excitation, a clear footprint for a parametric
resonance between magnetosonic waves and Alfv\'en waves.",2010.15565v1
2022-09-07,Solitary wave interactions with a periodic forcing: the extended Korteweg-de Vries framework,"The aim of this work is to study numerically the interaction of large
amplitude solitary waves with an external periodic forcing using the forced
extended Korteweg-de Vries equation (feKdV). Regarding these interactions, we
find that a solitary wave can bounce back and forth remaining close to its
initial position when the forcing and the solitary wave are near resonant or it
can move away from its initial position without reversing their direction.
Additionally, we verify that the numerical results agree well within the
asymptotic approximation for broad the forcings.",2209.03085v1
2023-07-24,On the transverse stability of smooth solitary waves in a two-dimensional Camassa-Holm equation,"We consider the propagation of smooth solitary waves in a two-dimensional
generalization of the Camassa--Holm equation. We show that transverse
perturbations to one-dimensional solitary waves behave similarly to the KP-II
theory. This conclusion follows from our two main results: (i) the double
eigenvalue of the linearized equations related to the translational symmetry
breaks under a transverse perturbation into a pair of the asymptotically stable
resonances and (ii) small-amplitude solitary waves are linearly stable with
respect to transverse perturbations.",2307.12821v1
2015-05-11,Black hole spin inferred from 3:2 epicyclic resonance model of high-frequency quasi-periodic oscillations,"Estimations of black hole spin in the three Galactic microquasars GRS
1915+105, GRO J1655-40, and XTE J1550-564 have been carried out based on
spectral and timing X-ray measurements and various theoretical concepts. Among
others, a non-linear resonance between axisymmetric epicyclic oscillation modes
of an accretion disc around a Kerr black hole has been considered as a model
for the observed high-frequency quasi-periodic oscillations (HF QPOs).
Estimates of spin predicted by this model have been derived based on the
geodesic approximation of the accreted fluid motion. Here we assume accretion
flow described by the model of a pressure-supported torus and carry out related
corrections to the mass-spin estimates. We find that for dimensionless black
hole spin a<0.9, the resonant eigenfrequencies are very close to those
calculated for the geodesic motion. Their values slightly grow with increasing
torus thickness. These findings agree well with results of a previous study
carried out in the pseudo-Newtonian approximation. The situation becomes
different for a>0.9, in which case the resonant eigenfrequencies rapidly
decrease as the torus thickness increases. We conclude that the assumed
non-geodesic effects shift the lower limit of the spin, implied for the three
microquasars by the epicyclic model and independently measured masses, from
a~0.7 to a~0.6. Their consideration furthermore confirms compatibility of the
model with the rapid spin of GRS 1915+105 and provides highly testable
predictions of the QPO frequencies. Individual sources with a moderate spin
(a<0.9) should exhibit a smaller spread of the measured 3:2 QPO frequencies
than sources with a near-extreme spin (a~1). This should be further examined
using the large amount of high-resolution data expected to become available
with the next generation of X-ray instruments, such as the proposed Large
Observatory for X-ray Timing (LOFT).",1505.02712v1
2005-02-01,Can Frustration Preserve a Quasi-Two-Dimensional Spin Fluid?,"Using spin-wave theory, we show that geometric frustration fails to preserve
a two-dimensional spin fluid. Even though frustration can remove the interlayer
coupling in the ground-state of a classical anti-ferromagnet, spin layers
innevitably develop a quantum-mechanical coupling via the mechanism of ``order
from disorder''. We show how the order from disorder coupling mechanism can be
viewed as a result of magnon pair tunneling, a process closely analogous to
pair tunneling in the Josephson effect. In the spin system, the Josephson
coupling manifests itself as a a biquadratic spin coupling between layers, and
for quantum spins, these coupling terms are as large as the inplane coupling.
An alternative mechanism for decoupling spin layers occurs in classical XY
models in which decoupled ""sliding phases"" of spin fluid can form in certain
finely tuned conditions. Unfortunately, these finely tuned situations appear
equally susceptible to the strong-coupling effects of quantum tunneling,
forcing us to conclude that in general, geometric frustration cannot preserve a
two-dimensional spin fluid.",0502003v2
2005-11-11,The time dependence of muon spin relaxation spectra and spin correlation functions,"The existing theory of the microscopic interpretation of the dynamical
contribution to zero-field muon depolarization spectra in a longitudinal
geometry is developed. The predicted relaxation of the muon depolarization is
calculated from two forms of the spin correlation function. First, when the
spin correlation function has an exponential form with a single wave vector
dependent relaxation rate is considered, it is shown that this form of the spin
correlation function reproduces the slow and fast fluctuation limits of
stochastic spin theory regardless of the choice of microscopic spin model.
Second, if the spin correlation function is a homogeneous scaling function
(such as a power-law decay with time), as suggested by the mode-coupling theory
of spin dynamics, this results in a stretched exponential relaxation of the
muon spectra. For simple spin diffusion, the muon spectra are shown to be relax
with a root-exponential form.",0511288v1
2010-06-15,Non-magnetic Stern-Gerlach Experiment from Electron Diffraction,"Using the wave nature of the electrons, we demonstrate that a transverse spin
current can be generated simply by the diffraction through a single slit in the
spin-orbital coupling system of the two-dimensional electron gas. The
diffracted electron picks up the transverse momentum. The up spin electron goes
one way and the down spin electron goes the other, producing the coherent spin
current. In the system of spin-orbital coupling $\sim10^{-13}$ eV$\cdot$m, the
\emph{out-of-plane} component of the spin of the electron can be generated up
to 0.42 $\hbar$. Based on this effect, a novel device of grating to distill
spin is designed. Two first diffraction peaks of electron carry different
spins, duplicating the non-magnetic version of Stern-Gerlach experiment. The
direction of the spin current can be controlled by the gate voltage with low
energy cost.",1006.2872v1
2010-11-23,Spin Period Evolution of Recycled Pulsar in Accreting Binary,"We investigate the spin-period evolutions of recycled pulsars in binary
accreting systems. Taking both the accretion induced field decay and spin-up
into consideration, we calculate their spin-period evolutions influenced by the
initial magnetic-field strengths, initial spin-periods and accretion rates,
respectively. The results indicate that the minimum spin-period (or maximum
spin frequency) of millisecond pulsar (MSP) is independent of the initial
conditions and accretion rate when the neutron star (NS) accretes $\sim>
0.2\ms$. The accretion torque with the fastness parameter and gravitational
wave (GW) radiation torque may be responsible for the formation of the minimum
spin-period (maximum spin frequency). The fastest spin frequency (716 Hz) of
MSP can be inferred to associate with a critical fastness parameter about
$\omega_{c}=0.55$. Furthermore, the comparisons with the observational data are
presented in the field-period ($B-P$) diagram.",1011.5013v1
2014-12-18,Spinor Bose gas in an elongated trap,"We examine a spinor Bose gas confined by an elongated trap. Since a
spin-independent energy is much higher than a spin-dependent energy in alkali
species, the system exhibits different properties by changing a radial
confinement. We show that if a spin-dependent coupling is positive, a
spin-liquid condensate, which breaks the charge U(1) symmetry but preserves the
spin rotational symmetry, can be realized in an intermediate confinement
regime. Properties of the spin-liquid condensate are visible if a temperature
is lower than a spin gap to characterize the spin-disorder property. If a
temperature is higher than the gap but lower than a spin-dependent coupling, on
the other hand, a regime in which a spin sector is described by a semiclassical
wave emerges. A characterization in each regime by means of correlation
functions and topological solitons is also discussed.",1412.6066v2
2015-02-13,Spin Dynamics with Inertia in Metallic Ferromagnets,"Non-adiabatic contribution of environmental degrees of freedom yields
effective inertia of spin in effective spin dynamics. In this paper, we study
several aspects of the inertia of spin in metallic ferromagnets. (i) a concrete
expression of the spin inertia $m_s$: $m_s=\hbar S_c/(2g_{\rm sd})$, where
$S_c$ is the spin polarization of conduction electrons and $g_{\rm sd}$ is the
$sd$ coupling constant. (ii) dynamical behavior of spin with inertia, discussed
from viewpoints of a spinning top and of a particle on a sphere. (iii) behavior
of spin waves and domain walls in the presence of inertia, and behavior of spin
with inertia in the case of a time-dependent magnetic field.",1502.04107v2
2015-05-06,Reexamination of the Elliott-Yafet spin-relaxation mechanism,"We analyze spin-dependent carrier dynamics due to incoherent electron-phonon
scattering, which is commonly referred to as Elliott-Yafet (EY) spin-relaxation
mechanism. For this mechanism one usually distinguishes two contributions: (1)
from the electrostatic interaction together with spin-mixing in the wave
functions, which is often called the Elliott contribution, and (2) the
phonon-modulated spin-orbit interaction, which is often called the Yafet or
Overhauser contribution. By computing the reduced electronic density matrix, we
improve Yafet's original calculation, which is not valid for pronounced spin
mixing as it equates the pseudo-spin polarization with the spin polarization.
The important novel quantity in our calculation is a torque operator that
determines the spin dynamics. The contribution (1) to this torque vanishes
exactly. From this general result, we derive a modified expression for the
Elliott-Yafet spin relaxation time.",1505.01432v2
2015-07-22,Observation of correlated spin-orbit order in a strongly anisotropic quantum wire system,"Quantum wires with spin-orbit coupling provide a unique opportunity to
simultaneously control the coupling strength and the screened Coulomb
interactions where new exotic phases of matter can be explored. Here we report
on the observation of an exotic spin-orbit density wave in Pb-atomic wires on
Si(557) surfaces by mapping out the evolution of the modulated spin-texture at
various conditions with spin- and angle-resolved photoelectron spectroscopy.
The results are independently quantified by surface transport measurements. The
spin polarization, coherence length, spin dephasing rate, and the associated
quasiparticle gap decrease simultaneously as the screened Coulomb interaction
decreases with increasing excess coverage, providing a new mechanism for
generating and manipulating a spin-orbit entanglement effect via electronic
interaction. Despite clear evidence of spontaneous spin-rotation symmetry
breaking and modulation of spin-momentum structure as a function of excess
coverage, the average spin-polarization over the Brillouin zone vanishes,
indicating that time-reversal symmetry is intact as theoretically predicted.",1507.06152v1
2015-07-23,Minimal Model of Spin-Transfer Torque and Spin Pumping caused by Spin Hall Effect,"In the normal metal/ferromagnetic insulator bilayer (such as
Pt/Y$_{3}$Fe$_{5}$O$_{12}$) and the normal metal/ferromagnetic metal/oxide
trilayer (such as Pt/Co/AlO$_{x}$) where spin injection and ejection are
achieved by the spin Hall effect in the normal metal, we propose a minimal
model based on quantum tunneling of spins to explain the spin-transfer torque
and spin pumping caused by the spin Hall effect. The ratio of their
damping-like to field-like component depends on the tunneling wave function
that is strongly influenced by generic material properties such as interface
$s-d$ coupling, insulating gap, and layer thickness, yet the spin relaxation
plays a minor role. The quantified result renders our minimal model an
inexpensive tool for searching for appropriate materials.",1507.06447v2
2016-04-06,Strong spin-orbit fields and Dyakonov-Perel spin dephasing in supported metallic films,"Spin dephasing by the Dyakonov-Perel mechanism in metallic films deposited on
insulating substrates is revealed, and quantitatively examined by means of
density functional calculations combined with a kinetic equation. The
surface-to-substrate asymmetry, probed by the metal wave functions in thin
films, is found to produce strong spin-orbit fields and a fast Larmor
precession, giving a dominant contribution to spin decay over the Elliott-Yafet
spin relaxation up to a thickness of 70 nm. The spin dephasing is oscillatory
in time with a rapid (sub-picosecond) initial decay. However, parts of the
Fermi surface act as spin traps, causing a persistent tail signal lasting 1000
times longer than the initial decay time. It is also found that the decay
depends on the direction of the initial spin polarization, resulting in a
spin-dephasing anisotropy of 200% in the examined cases.",1604.01559v1
2016-04-21,Electron spin filter and polarizer in a standing light wave,"We demonstrate the theoretical feasibility of spin-dependent diffraction and
spin-polarization of an electron in two counter-propagating, circularly
polarized laser beams. The spin-dynamics appears in a two-photon process of the
Kapitza-Dirac effect in the Bragg regime. We show the spin-dependence of the
diffraction process by comparison of the time-evolution of a spin-up and
spin-down electron in a relativistic quantum simulation. We further discuss the
spin properties of the scattering by studying an analytically approximated
solution of the time-evolution matrix. A classification scheme in terms of
unitary or non-unitary propagation matrices is used for establishing a
generalized and spin-independent description of the spin properties in the
diffraction process.",1604.06201v5
2017-07-27,Are the observed black hole mergers spins consistent with field binary progenitors?,"One of the puzzles in the recent observations of gravitational waves from
binary black hole mergers is the observed low (projected) spins of the
progenitor black holes. In two of the four events, GW150914, and the recent
GW170104, the observed spins are most likely negative (but consistent with
zero). In the third case LVT151012 it is practically zero and only in the forth
case, GW151226, the spin is positive but low. These observations are puzzling
within the field binary scenario in which positive higher spins are expected.
Considering the most favorable Wolfe Rayet (WR) progenitors we estimate the
expected spin distribution for different evolution scenarios and compare it to
the observations. With typical parameters one expects a significant fraction
($\ge 25\%$) of the mergers to have high effective spin values. However due to
uncertainties in the outcome of the common envelope phase (typical separation
and whether the stars are rotating or not) and in the late stages of massive
star evolution (the strength of the winds) one cannot rule our scenarios in
which the expected spins are low. While observations of high effective spin
events will support this scenario, further observations of negative spin events
would rule it out.",1707.08978v1
2008-06-27,Controllable spin-current blockade in a Hubbard chain,"We investigate the spin/charge transport in a one-dimensional strongly
correlated system by using the adaptive time-dependent density-matrix
renormalization group method. The model we consider is a non-half-filled
Hubbard chain with a bond of controllable spin-dependent electron hoppings,
which is found to cause a blockade of spin current with little influence on
charge current. We have considered (1) the spread of a wave packet of both spin
and charge in the Hubbard chain and (2) the spin and charge currents induced by
a spin-dependent voltage bias that is applied to the ideal leads attached at
the ends of this Hubbard chain. It is found that the spin-charge separation
plays a crucial role in the spin-current blockade, and one may utilize this
phenomenon to observe the spin-charge separation directly.",0806.4494v1
2021-06-14,Quantum spin liquid in an RKKY-coupled two-impurity Kondo system,"We consider a 2-impurity Kondo system with spin-exchange coupling within the
conduction band. Our numerical renormalization group calculations show that for
strong intraband spin correlations the competition of these correlations with
Kondo spin screening stabilizes a metallic spin-liquid phase of the localized
spins without geometric frustration. For weak Kondo coupling the spin liquid
and the Kondo singlet phase are separated by two quantum phase transitions and
an intermediate RKKY spin-dimer phase, while beyond a critical coupling they
are connected by a crossover. The results suggest how a quantum spin liquid may
be realized in heavy-fermion systems near a spin-density wave instability.",2106.07519v3
2021-12-06,Unified formulation of interfacial magnonic pumping from non-collinear magnets,"We establish a general formulation for spin current pumped by magnons at the
interface between a normal metal and a magnetic insulator, valid for any
non-collinear magnetic configuration in the linear spin wave regime. This
current is generated by driving the system in a non-equilibrium state, covering
setups such as thermal spin injection (spin Seebeck effect) or spin voltage by
irradiation of the insulator (spin pumping). We illustrate the formula in the
special case of a honeycomb topological ferromagnet, for simplicity, and cover
both the spin Seebeck and spin-pumping setups. We show how the topological
parameters influence the spin current and propose a way to obtain a
contribution mainly from the topological edge magnons in the spin pumping case.",2112.02946v1
2024-02-06,The spin alignment of rho mesons in a pion gas,"We study the spin alignment of neutral rho mesons in a pion gas using spin
kinetic or Boltzmann equations. The $\rho\pi\pi$ coupling is given by the
chiral effective theory. The collision terms at the leading and next-to-leading
order in spin Boltzmann equations are derived. The evolution of the spin
density matrix of the neutral rho meson is simulated with different initial
conditions. The numerical results show that the interaction of pions and
neutral rho mesons creates very small spin alignment in the central rapidity
region if there is no rho meson in the system at the initial time. Such a small
spin alignment in the central rapidity region will decay rapidly toward zero in
later time. If there are rho mesons with a sizable spin alignment at the
initial time the spin alignment will also decrease rapidly. We also considered
the effect on $\rho_{00}$ from the elliptic flow of pions in the blast wave
model. With vanishing spin alignment at the initial time, the deviation of
$\rho_{00}$ from 1/3 is positive but very small.",2402.03672v1
1999-01-14,Gravitational waves from a test particle scattered by a neutron star: Axial mode case,"Using a metric perturbation method, we study gravitational waves from a test
particle scattered by a spherically symmetric relativistic star. We calculate
the energy spectrum and the waveform of gravitational waves for axial modes.
Since metric perturbations in axial modes do not couple to the matter fluid of
the star, emitted waves for a normal neutron star show only one peak in the
spectrum, which corresponds to the orbital frequency at the turning point,
where the gravitational field is strongest. However, for an ultracompact star
(the radius $R \lesssim 3M$), another type of resonant periodic peak appears in
the spectrum. This is just because of an excitation by a scattered particle of
axial quasinormal modes, which were found by Chandrasekhar and Ferrari. This
excitation comes from the existence of the potential minimum inside of a star.
We also find for an ultracompact star many small periodic peaks at the
frequency region beyond the maximum of the potential, which would be due to a
resonance of two waves reflected by two potential barriers (Regge-Wheeler type
and one at the center of the star). Such resonant peaks appear neither for a
normal neutron star nor for a Schwarzschild black hole. Consequently, even if
we analyze the energy spectrum of gravitational waves only for axial modes, it
would be possible to distinguish between an ultracompact star and a normal
neutron star (or a Schwarzschild black hole).",9901040v2
2001-11-16,Resonances and superlattice pattern stabilization in two-frequency forced Faraday waves,"We investigate the role weakly damped modes play in the selection of Faraday
wave patterns forced with rationally-related frequency components m*omega and
n*omega. We use symmetry considerations to argue for the special importance of
the weakly damped modes oscillating with twice the frequency of the critical
mode, and those oscillating primarily with the ""difference frequency""
|n-m|*omega and the ""sum frequency"" (n+m)*omega. We then perform a weakly
nonlinear analysis using equations of Zhang and Vinals (1997, J. Fluid Mech.
336) which apply to small-amplitude waves on weakly inviscid, semi-infinite
fluid layers. For weak damping and forcing and one-dimensional waves, we
perform a perturbation expansion through fourth order which yields analytical
expressions for onset parameters and the cubic bifurcation coefficient that
determines wave amplitude as a function of forcing near onset. For stronger
damping and forcing we numerically compute these same parameters, as well as
the cubic cross-coupling coefficient for competing waves travelling at an angle
theta relative to each other. The resonance effects predicted by symmetry are
borne out in the perturbation results for one spatial dimension, and are
supported by the numerical results in two dimensions. The difference frequency
resonance plays a key role in stabilizing superlattice patterns of the SL-I
type observed by Kudrolli, Pier and Gollub (1998, Physica D 123).",0111039v2
2009-04-17,On electromagnetic instabilities at ultra-relativistic shock waves,"(Abridged) This paper addresses the issue of magnetic field generation in a
relativistic shock precursor through micro-instabilities. The level of
magnetization of the upstream plasma turns out to be a crucial parameter,
notably because the length scale of the shock precursor is limited by the
Larmor rotation of the accelerated particles in the background magnetic field
and by the speed of the shock wave. We discuss in detail and calculate the
growth rates of the following beam plasma instabilities seeded by the
accelerated and reflected particle populations: for an unmagnetized shock, the
Weibel and filamentation instabilities, as well as the Cerenkov resonant
longitudinal and oblique modes; for a magnetized shock, the Weibel instability
and the resonant Cerenkov instabilities with the longitudinal electrostatic
modes, as well as the Alfven, Whisler and extraordinary modes. All these
instabilities are generated upstream, then they are transmitted downstream. The
modes excited by Cerenkov resonant instabilities take on particular importance
with respect to the magnetisation of the downstream medium since, being plasma
eigenmodes, they have a longer lifetime than the Weibel modes. We discuss the
main limitation of the wave growth associated with the length of the precursor
and the magnetisation of the upstream medium for both oblique and parallel
shock waves. We also characterize the proper conditions to obtain Fermi
acceleration. We recover some results of most recent particle-in-cell
simulations and conclude with some applications to astrophysical cases of
interest, pulsar winds and gamma-ray burst external shock waves in particular.
(Abridged)",0904.2657v2
2017-07-19,Toward Microphononic Circuits on Chip: An Evaluation of Components based on High-Contrast Evanescent Confinement of Acoustic Waves,"We investigate the prospects for micron-scale acoustic wave components and
circuits on chip in solid planar structures that do not require suspension. We
leverage evanescent guiding of acoustic waves by high slowness contrast
materials readily available in silicon complementary metal-oxide semiconductor
(CMOS) processes. High slowness contrast provides strong confinement of GHz
frequency acoustic fields in micron-scale structures. We address the
fundamental implications of intrinsic material and radiation losses on
operating frequency, bandwidth, device size and as a result practicality of
multi-element microphononic circuits based on solid embedded waveguides. We
show that a family of acoustic components based on evanescently guided acoustic
waves, including waveguide bends, evanescent couplers, Y-splitters, and
acoustic-wave microring resonators, can be realized in compact, micron-scale
structures, and provide basic scaling and performance arguments for these
components based on material properties and simulations. We further find that
wave propagation losses are expected to permit high quality factor (Q),
narrowband resonators and propagation lengths allowing delay lines and the
coupling or cascading of multiple components to form functional circuits, of
potential utility in guided acoustic signal processing on chip. We also address
and simulate bends and radiation loss, providing insight into routing and
resonators. Such circuits could be monolithically integrated with electronic
and photonic circuits on a single chip with expanded capabilities.",1707.06280v1
2019-06-14,Resonant Decay of Gravitational Waves into Dark Energy,"We study the decay of gravitational waves into dark energy fluctuations
$\pi$, taking into account the large occupation numbers. We describe dark
energy using the effective field theory approach, in the context of generalized
scalar-tensor theories. When the $m_3^3$ (cubic Horndeski) and $\tilde m_4^2$
(beyond Horndeski) operators are present, the gravitational wave acts as a
classical background for $\pi$ and modifies its dynamics. In particular, $\pi$
fluctuations are described by a Mathieu equation and feature instability bands
that grow exponentially. Focusing on the regime of small gravitational-wave
amplitude, corresponding to narrow resonance, we calculate analytically the
produced $\pi$, its energy and the change of the gravitational-wave signal. The
resonance is affected by $\pi$ self-interactions in a way that we cannot
describe analytically. This effect is very relevant for the operator $m_3^3$
and it limits the instability. In the case of the $\tilde m_4^2$ operator
self-interactions can be neglected, at least in some regimes. The modification
of the gravitational-wave signal is observable for $3 \times 10^{-20} \lesssim
\alpha_{\rm H} \lesssim 10^{-17}$ with a LIGO/Virgo-like interferometer and for
$10^{-16} \lesssim \alpha_{\rm H} \lesssim 10^{-10}$ with a LISA-like one.",1906.07015v2
2013-04-11,Intrinsic Spin Hall Effect at Oxide Interfaces: a Simple Model,"An asymmetric triangular potential well provides the simplest model for the
confinement of mobile electrons at the interface between two insulating oxides,
such as LaAlO_3 and SrTiO_3 (LAO/STO). These electrons have been recently shown
to exhibit a large spin-orbit coupling of the Rashba type, i.e., linear in the
in-plane momentum. In this paper we study the intrinsic spin Hall effect due to
Rashba coupling in an asymmetric triangular potential well. Besides splitting
each subband into two branches of opposite helicity, the spin-orbit interaction
causes the wave function in the direction perpendicular to the plane of the
quantum well (the z direction) to depend on the in-plane wave vector k. In
contrast to the extreme asymmetric case, i.e., the wedge-shaped quantum well,
for which the intrinsic spin Hall effect vanishes due to vertex corrections, we
find that the asymmetric well supports a non-vanishing intrinsic spin Hall
conductivity, which increases in magnitude as the well becomes more symmetric.
The spin Hall conductivity is found to be proportional to the square of the
spin-orbit coupling constant and, in the limit of low carrier density, depends
only on the effective mass renormalization associated with the k-dependence of
the wave functions in the z direction. Its origin lies in the non-vanishing
matrix elements of the spin current between subbands corresponding to different
states of quantized motion perpendicular to the plane of the well.",1304.3476v2
2016-08-03,Coupling a Surface Acoustic Wave to an Electron Spin in diamond via a Dark State,"The emerging field of quantum acoustics explores interactions between
acoustic waves and artificial atoms and their applications in quantum
information processing. In this experimental study, we demonstrate the coupling
between a surface acoustic wave (SAW) and an electron spin in diamond by taking
advantage of the strong strain coupling of the excited states of a nitrogen
vacancy center, while avoiding the short lifetime of these states. The SAW-spin
coupling takes place through a lamda-type three-level system where two ground
spin states couple to a common excited state through a phonon-assisted as well
as a direct dipole optical transition. Both coherent population trapping and
optically-driven spin transitions have been realized. The coherent population
trapping demonstrates the coupling between a SAW and an electron spin coherence
through a dark state. The optically-driven spin transitions, which resemble the
sideband transitions in a trapped ion system, can enable the quantum control of
both spin and mechanical degrees of freedom and potentially a trapped-ion-like
solid state system for applications in quantum computing. These results
establish an experimental platform for spin-based quantum acoustic, bridging
the gap between spintronics and quantum acoustics.",1608.01356v1
2017-06-05,Distinguishing Spin-Aligned and Isotropic Black Hole Populations With Gravitational Waves,"The first direct detections of gravitational waves from merging binary black
holes open a unique window into the binary black hole formation environment.
One promising environmental signature is the angular distribution of the black
hole spins; systems formed through dynamical interactions among already-compact
objects are expected to have isotropic spin orientations whereas binaries
formed from pairs of stars born together are more likely to have spins
preferentially aligned with the binary orbital angular momentum. We consider
existing gravitational wave measurements of the binary effective spin, the
best-measured combination of spin parameters, in the four likely binary black
hole detections GW150914, LVT151012, GW151226, and GW170104. If binary black
hole spin magnitudes extend to high values we show that the data exhibit a
$2.4\sigma$ ($0.015$ odds ratio) preference for an isotropic angular
distribution over an aligned one. By considering the effect of 10 additional
detections, we show that such an augmented data set would enable in most cases
a preference stronger than $5\sigma$ ($2.9 \times 10^{-7}$ odds ratio). The
existing preference for either an isotropic spin distribution or low spin
magnitudes for the observed systems will be confirmed (or overturned)
confidently in the near future.",1706.01385v2
2020-06-12,Spin Excitations and Spin Wave Gap in the Ferromagnetic Weyl Semimetal Co$_3$Sn$_2$S$_2$,"We report a comprehensive neutron scattering study on the spin excitations in
the magnetic Weyl semimetal Co$_3$Sn$_2$S$_2$ with quasi-two-dimensional
structure. Both in-plane and out-of-plane dispersions of the spin waves are
revealed in the ferromagnetic state, similarly dispersive but damped spin
excitations persist into the paramagnetic state. The effective exchange
interactions have been estimated by a semi-classical Heisenberg model to
consistently reproduce the experimental $T_C$ and spin stiffness. However, a
full spin wave gap below $E_g=2.3$ meV is observed at $T=4$ K, much larger than
the estimated magnetic anisotropy energy ($\sim0.6$ meV), while its temperature
dependence indicates a significant contribution from the Weyl fermions. These
results suggest that Co$_3$Sn$_2$S$_2$ is a three-dimensional correlated system
with large spin stiffness, and the low-energy spin dynamics could interplay
with the topological electron states.",2006.07339v2
2022-09-06,The population properties of spinning black holes using Gravitational-wave Transient Catalog 3,"Binary black holes formed via different pathways are predicted to have
distinct spin properties. Measuring these properties with gravitational waves
provides an opportunity to unveil the origins of binary black holes. Recent
work draws conflicting conclusions regarding the spin distribution observed by
LIGO--Virgo--KAGRA (LVK). Some analyses suggest that a fraction of the observed
black-hole spin vectors are significantly misaligned (by $>90^\circ$) relative
to the orbital angular momentum. This has been interpreted to mean that some
binaries in the LVK dataset are assembled dynamically in dense stellar
environments. Other analyses find support for a sub-population of binaries with
negligible spin and no evidence for significantly misaligned spin -- a result
consistent with the field formation scenario. In this work, we study the spin
properties of binary black holes in the third LVK gravitational-wave transient
catalog. We find that there is insufficient data to resolve the existence of a
sub-population of binaries with negligible black-hole spin (the presence of
this sub-population is supported by a modest Bayes factor of 1.7). We find
modest support for the existence of mergers with extreme spin tilt angles $>
90^\circ$ (the presence of extreme-tilt binaries is favored by a Bayes factor
of 10.1). Only one thing is clear: at least some of the LVK binaries formed in
the field. At most $89\%$ of binaries are assembled dynamically (99\%
credibility), though, the true branching fraction could be much lower, even
negligible.",2209.02206v2
2004-09-02,Excitation of Disk Oscillations by Warps: A Model of kHz QPOs,"The amplification of disk oscillations resulting from non-linear resonant
couplings between the oscillations and a warp is examined. The disks are
geometrically thin and general relativistic with non-rotating central objects.
By using a Lagrangian formulation, a general stability criterion is derived.
The criterion is applied to horizontal and vertical resonances of g-mode
oscillations and to horizontal resonances of p-mode oscillations. The results
of analyses show that g-mode oscillations (including p-mode oscillations of
$n=0$) are amplified by horizontal resonances with the warp. Other modes of
oscillations with other resonances are all damped by resonances. The amplified
g-mode oscillations are located around the radius $4r_{\rm g}$, the radius of
the epicyclic frequency being maximum, i.e., $\kappa_{\rm max}$. The
frequencies of amplified oscillations are harmonics of $\kappa_{\rm max}$, and
well explain the 2 : 3 pairs of observed QPOs for reasonable masses (and spins)
of the central objects.",0409051v2
2004-10-07,Boson-Fermion Resonance Model in One Dimension,"We discuss the BCS-BEC crossover for one-dimensional spin 1/2 fermions at
zero temperature using the Boson-Fermion resonance model in one dimension. We
show that in the limit of a broad resonance, this model is equivalent to an
exactly solvable single channel model, the so-called modified Gaudin-Yang
model. We argue that the one-dimensional crossover may be realized either via
the combination of a Feshbach resonance and a confinement induced resonance or
using direct photo-association in a two-component Fermi gas with effectively
one-dimensional dynamics. In both cases, the system may be driven from a
BCS-like state through a molecular Tonks-Girardeau gas close to resonance to a
weakly interacting Bose gas of dimers.",0410183v1
2007-02-20,Impurity resonant state in d-wave superconductors: in favor of a Kondo-like response,"We investigate the impurity resonant state induced by non-magnetic impurities
in d-wave cuprate superconductors in two different impurity models: (i) in a
pure potential scattering model within the T-matrix approach and (ii) in a
Bose-Fermi Kondo model within the large-N formalism. We modify the
superconducting host to resemble the nanoscale electronic inhomogeneities seen
in the scanning tunneling microscopy (STM) spectra (i.e., the small- and
large-gap domains) and study how this influences the impurity resonance. In the
pure potential scattering model the resonant state is found to be a rather
robust feature appearing in all host domains. On the other hand, in the
Kondo-like model the impurity resonance can appear in the small-gap regions of
the host and be completely suppressed in the large-gap regions; this is in
agreement with the STM experimental data for Zn-doped BSCCO. Our results imply
that the Kondo spin dynamics of the impurity moment is the origin of the
impurity resonant state in d-wave superconductors, rather than the pure
potential scattering.",0702457v1
2000-06-12,Searching for Narrow Graviton Resonances with the ATLAS Detector at the Large Hadron Collider,"A spectrum of massive graviton states is present in several recent
theoretical models that include extra space dimensions. In some such models the
graviton states are well separated in mass, and can be detected as resonances
in collider experiments. The ability of the ATLAS detector at the Large Hadron
Collider to identify such states and measure their properties is considered, in
the case that the resonances are narrow compared to the experimental
resolution. The discovery limits for the detection of the decay mode G->e+e-
are derived. The angular distribution of the lepton pair is used to determine
the spin of the intermediate state. In one specific model, the resonance can be
detected up to a graviton resonance mass of 2080 GeV, while the angular
distribution favours a spin-2 hypothesis over a spin-1 hypothesis at 90%
confidence for resonance masses up to 1720 GeV.",0006114v2
2008-10-27,Investigation of resonant and transient phenomena in Josephson junction flux qubits,"We present an analytical and computational study of resonances and transient
responses in a classical Josephson junction system. A theoretical basis for
resonances in a superconducting loop with three junctions is presented,
outlining both the direct relationship between the dynamics of single- and
multi-junction systems, and the direct relationships between observations of
the classical counterparts to Rabi oscillations, Ramsey fringes, and spin echo
oscillations in this class of systems. We show simulations data along with
analytical analyses of the classical model, and the results are related to
previously reported experiments conducted on three junction loops. We further
investigate the effect of off-resonant microwave perturbations to, e.g., the
Rabi-type response of the Josephson system, and we relate this response back to
the nonlinear and multi-valued resonance behavior previously reported for a
single Josephson junction. The close relationships between single and
multi-junction behavior demonstrates the underlying dynamical mechanism for a
whole class of classical counterparts to expected quantum mechanical
observations in a variety of systems; namely the resonant and transient
behavior of a particle in an anharmonic potential well with subsequent escape.",0810.4731v2
2010-08-30,A closer look at string resonances in dijet events at the LHC,"The first string excited state can be observed as a resonance in dijet
invariant mass distributions at the LHC, if the scenario of low-scale string
with large extra dimensions is realized. A distinguished property of the dijet
resonance by string excited states from that the other ""new physics"" is that
many almost degenerate states with various spin compose a single resonance
structure. It is examined that how we can obtain evidences of low-scale string
models through the analysis of angular distributions of dijet events at the
LHC. Some string resonance states of color singlet can obtain large mass shifts
through the open string one-loop effect, or through the mixing with closed
string states, and the shape of resonance structure can be distorted. Although
the distortion is not very large (10% for the mass squared), it might be able
to observe the effect at the LHC, if gluon jets and quark jets could be
distinguished in a certain level of efficiency.",1008.4989v2
2011-11-28,"Bayesian inference of the resonance content of p(gamma,K^+)Lambda","A Bayesian analysis of the world's p(gamma,K^+)Lambda data is presented. From
the proposed selection of 11 resonances, we find that the following nucleon
resonances have the highest probability of contributing to the reaction:
S11(1535), S11(1650), F15(1680), P13(1720), D13(1900), P13(1900), P11(1900),
and F15(2000). We adopt a Regge-plus-resonance framework featuring consistent
couplings for nucleon resonances up to spin J=5/2. We evaluate all possible
combinations of 11 candidate resonances. The best model is selected from the
2048 model variants by calculating the Bayesian evidence values against the
world's p(gamma,K^+)Lambda data.",1111.6511v2
2012-11-09,Observation of interspecies Li-Cs Feshbach resonances,"We report on the observation of nineteen interspecies Feshbach resonances in
an optically trapped ultracold Bose-Fermi mixture of ^{133}Cs and ^{6}Li in the
two energetically lowest spin states. We assign the resonances to s- and p-wave
molecular channels by a coupled-channels calculation, resulting in an accurate
determination of LiCs ground state potentials. Fits of the resonance position
based on the undressed Asymptotic Bound State model do not provide the same
level of accuracy as the coupled-channels calculation. Several broad s-wave
resonances provide prospects to create fermionic LiCs molecules with a large
dipole moment via Feshbach association followed by stimulated Raman passage.
Two of the s-wave resonances overlap with a zero crossing of the Cs scattering
length which offers prospects for the investigation of polarons in an ultracold
Li-Cs mixture.",1211.2139v2
2012-12-21,Feshbach resonances in ultracold 85Rb,"We present 17 experimentally confirmed Feshbach resonances in optically
trapped 85Rb. Seven of the resonances are in the ground-state channel (f,m_f) =
(2,+2)+(2,+2), and nine are in the excited-state channel (2,-2)+(2,-2). We find
a wide resonance at high field in each of the two channels, offering new
possibilities for the formation of larger 85Rb condensates and studies of
few-body physics. A detailed coupled-channels analysis is presented to
characterize the resonances, and also provides an understanding of the
inelastic losses observed in the excited-state channel. In addition we have
confirmed the existence of one narrow resonance in a (2,+2)+(3,+3) spin
mixture.",1212.5446v1
2014-11-25,Optimization of Coplanar Waveguide Resonators for ESR Studies on Metals,"We present simulations and analytic calculations of the electromagnetic
microwave fields of coplanar waveguide (CPW) resonators in the vicinity of
highly conducting metallic samples. The CPW structures are designed with the
aim of investigating electron spin resonance (ESR) in metallic heavy-fermion
systems, in particular YbRh$_2$Si$_2$, close to the quantum critical point.
Utilizing CPW resonators for ESR experiments allows for studies at mK
temperatures and a wide range of freely selectable frequencies. It is therefore
of great interest to evaluate the performance of resonant CPW structures with
nearby metallic samples. Here we study the microwave fields at the sample
surface as a function of sample distance from the waveguide structure and
analyze the implications of the sample on the performance of the resonator. The
simulation results reveal an optimum sample distance for which the microwave
magnetic fields at the sample are maximized and thus best suited for ESR
studies.",1411.6858v1
2014-12-15,Attosecond time delay in the photoionization of Mn in the region of the $3p \rightarrow 3d$ giant resonance,"The initial insight into time delay in Mn photoionization in the region of
the $3p \to 3d$ giant autoionization resonance is gained in the framework of
the ""spin-polarized"" random phase approximation with exchange. The dramatic
effect of the giant autoionization resonance on time delay of photoemission
from the $3d$ and $4s$ valence subshells of the Mn atom is unraveled. Strong
sensitivity of the time delay of the $4s$ photoemission to the final-state term
of the ion-remainder [${\rm Mn^{+}}(4s^{1},$$^{5}S)$ vs.~${\rm
Mn^{+}}(4s^{1},$$^{7}S)$] is discovered. It is shown that photoionization time
delay in the autoionizing resonance region is explicitly associated with the
resonance lifetime, which can, thus, be directly measured in attosecond time
delay experiments. Similar features are expected to emerge in photoionization
time delays of other transition-metal and rare-earth atoms with half-filed
subshells that possess giant autoionization resonances as well.",1412.4730v2
2015-01-19,The twofold emergence of the $a_1$ axial vector meson in high energy hadronic production,"The high statistics COMPASS results on diffractive dissociation $\pi N
\rightarrow \pi \pi \pi N$ suggest that the isospin $I=1$ spin-parity $J^{PC}=
1^{++}$ $a_1(1260)$ resonance could be split into two states: $a_1(1260)$
decaying into an S-wave $\rho\pi$ system, and $a_1^\prime(1420)$ decaying into
a P-wave $f_0(980)\pi$ system. We analyse the reaction by incorporating our
previous treatment of resonant re-scattering corrections in the Drell-Deck
forward production process. Our results show that the COMPASS results are fully
consistent with the existence of a single axial-vector $a_1$ resonance. The
characteristic structure of the production process, which differs in the two
orbital angular momentum states, plays a crucial role in this determination.
Provided the theoretical analysis of the reaction is done in a consistent
manner, this single resonance produces two peaks at different locations in the
two channels, with a rapid increase of the phase difference between their
amplitudes arising mainly from the structure of the production process itself,
and not from a dynamical resonance effect. In addition, this analysis clarifies
questions related to the mass, width, and decay rates of the $a_1$ resonance.",1501.04643v1
2016-04-19,Resonance fluorescence and laser spectroscopy of three-dimensionally confined excitons in monolayer WSe$_2$,"Resonant optical excitation of few-level quantum systems enables coherent
quantum control, resonance fluorescence, and direct characterization of
dephasing mechanisms. Experimental demonstrations have been achieved in a
variety of atomic and solid-state systems. An alternative but intriguing
quantum photonic platform is based on single layer transition metal
chalcogenide semiconductors, which exhibit a direct band-gap with optically
addressable exciton valley-pseudospins in a uniquely two-dimensional form. Here
we perform resonance and near-resonance excitation of three-dimensionally
confined excitons in monolayer WSe$_2$ to reveal near ideal single photon
fluorescence with count rates up to 3 MHz and uncover a weakly-fluorescent
exciton state ~ 5 meV blue-shifted from the ground-state exciton. We perform
high-resolution photoluminescence excitation spectroscopy of the localized
excitons, providing important information to unravel the precise nature of the
quantum states. Successful demonstration of resonance fluorescence paves the
way to probe the localized exciton coherence. Moreover, these results yield a
route for investigations of the spin and valley coherence of confined excitons
in two-dimensional semiconductors.",1604.05522v1
2016-05-01,750 GeV diphoton resonance and electric dipole moments,"We examine the implication of the recently observed 750 GeV diphoton excess
for the electric dipole moments of the neutron and electron. If the excess is
due to a spin zero resonance which couples to photons and gluons through the
loops of massive vector-like fermions, the resulting neutron electric dipole
moment can be comparable to the present experimental bound if the CP-violating
angle {\alpha} in the underlying new physics is of O(10^{-1}). An electron EDM
comparable to the present bound can be achieved through a mixing between the
750 GeV resonance and the Standard Model Higgs boson, if the mixing angle
itself for an approximately pseudoscalar resonance, or the mixing angle times
the CP-violating angle {\alpha} for an approximately scalar resonance, is of
O(10^{-3}). For the case that the 750 GeV resonance corresponds to a composite
pseudo-Nambu-Goldstone boson formed by a QCD-like hypercolor dynamics confining
at \Lambda_HC, the resulting neutron EDM can be estimated with \alpha ~ (750
GeV / \Lambda_HC)^2\theta_HC, where \theta_HC is the hypercolor vacuum angle.",1605.00206v1
2017-09-05,Feshbach Loss Spectroscopy in an Ultracold $^{23}$Na and $^{40}$K Mixture,"We perform Feshbach spectroscopy in an ultracold mixture of $^{23}$Na and
$^{40}$K with different spin-state combinations. We have observed 24 new
interspecies Feshbach resonances at magnetic field up to 350 G. A full
coupled-channel calculation is performed to assign these resonances. Among
them, 12 resonances are identified as d-wave Feshbach resonances. These d-wave
Feshbach resonances are about 5 G systematically smaller than the predications
based on previous model potential. Taking into account these new experimental
results, we improve the Born-Oppenheimer potentials between Na and K, and
achieve good agreement between the theory and experiment for all the observed
Feshbach resonances.",1709.01260v1
2018-01-23,Photo- and electroproduction of $K^{+}Λ$ with unitarity-restored isobar model,"Exploiting the isobar model, kaon photo- and electroproduction on the proton
in the resonance region comes under scrutiny. An upgrade of our previous model,
comprising higher-spin nucleon and hyperon exchanges in the consistent
formalism, was accomplished by implementing energy-dependent widths of nucleon
resonances, which leads to a different choice of hadron form factor with much
softer values of cutoff parameter for the resonant part. For a reliable
description of electroproduction, the necessity of including longitudinal
couplings of nucleon resonances to virtual photons was revealed. We present a
new model whose free parameters were adjusted to photo- and electroproduction
data and which provides a reliable overall description of experimental data in
all kinematic regions. The majority of nucleon resonances chosen in this
analysis coincide with those selected in our previous analysis and also in the
Bayesian analysis with the Regge-plus-resonance model as the states
contributing to this process with the highest probability.",1801.07466v2
2018-10-30,Ultrasensitive Displacement Noise Measurement of Carbon Nanotube Mechanical Resonators,"Mechanical resonators based on a single carbon nanotube are exceptional
sensors of mass and force. The force sensitivity in these ultra-light
resonators is often limited by the noise in the detection of the vibrations.
Here, we report on an ultra-sensitive scheme based on a RLC resonator and a
low-temperature amplifier to detect nanotube vibrations. We also show a new
fabrication process of electromechanical nanotube resonators to reduce the
separation between the suspended nanotube and the gate electrode down to $\sim
150$~nm. These advances in detection and fabrication allow us to reach
$0.5~\mathrm{pm}/\sqrt{\mathrm{Hz}}$ displacement sensitivity. Thermal
vibrations cooled cryogenically at 300~mK are detected with a signal-to-noise
ratio as high as 17~dB. We demonstrate $4.3~\mathrm{zN}/\sqrt{\mathrm{Hz}}$
force sensitivity, which is the best force sensitivity achieved thus far with a
mechanical resonator. Our work is an important step towards imaging individual
nuclear spins and studying the coupling between mechanical vibrations and
electrons in different quantum electron transport regimes.",1810.12797v1
2016-03-12,Evidence for Some New Hyperon Resonances -- to be Checked by $K_L$ Beam Experiments,"Quenched and unquenched quark models predict very different patterns for the
spectrum of the low excited hyperon states. Evidence is accumulating for the
existence of some new hyperon resonances, such as a $\Sigma^*$ of spin-parity
$J^P=1/2^-$ around 1400 MeV instead of 1620 MeV as listed in PDG, a new
$\Sigma(1540)3/2^-$ resonance, a new narrow $\Lambda(1670)3/2^-$ resonance and
a new $\Lambda(1680)3/2^+$ resonance. All these new hyperon resonances fit in
the predicted pattern of the unquenched quark models very well. It is extremely
important to check and establish the spectrum of these low excited hyperon
states by the proposed $K_L$ beam experiments at JLAB.",1603.03927v1
2019-05-28,Magnetic Feshbach resonances in ultracold collisions between Cs and Yb atoms,"We investigate magnetically tunable Feshbach resonances in ultracold
collisions between ground-state Yb and Cs atoms, using coupled-channel
calculations based on an interaction potential recently determined from
photoassociation spectroscopy. We predict resonance positions and widths for
all stable isotopes of Yb, together with resonance decay parameters where
appropriate. The resonance patterns are richer and more complicated for
fermionic Yb than for spin-zero isotopes, because there are additional level
splittings and couplings due to scalar and tensorial Yb hyperfine interactions.
We examine collisions involving Cs atoms in a variety of hyperfine states, and
identify resonances that appear most promising for experimental observation and
for magnetoassociation to form ultracold CsYb molecules.",1905.11977v1
2021-10-13,The $Ω_{cc}$ resonances with negative parity in the chiral constituent quark model,"Spectrum of the low-lying $\Omega_{cc}$ resonances with negative parity,
which are assumed to be dominated by $sccq\bar{q}$ pentaquark components, is
investigated using the chiral constituent quark model. Energies of the
$\Omega_{cc}$ resonances are obtained by considering the hyperfine interaction
between quarks by exchanging Goldstone boson. Possible $sccq\bar{q}$
configurations with spin-parity $1/2^{-}$, $3/2^{-}$ and $5/2^{-}$ are taken
into account. Numerical results show that the lowest $\Omega_{cc}$ resonances
with negative parity may lie at $4050 \pm 100$ MeV. In addition, the
transitions of the $\Omega_{cc}$ resonance to a pseudoscalar meson and a ground
baryon state are also investigated within the chiral Lagrangian approach. We
expect that these $\Omega_{cc}$ resonances could be observed in the
$\bar{D}\Xi_{c}$ channel by future experiments.",2110.06408v2
2022-01-25,Strong decays of multi-strangeness baryon resonances in the quark model,"Decay properties of multi-strangeness $\Xi$ and $\Omega$ baryon resonances
are investigated within the constituent quark model by including relativistic
corrections. The strong decay widths of various $\Xi$ and $\Omega$ resonances
are computed and tested for internal quark configurations to pin down their
spin-parity ($J^P$) quantum numbers and internal structures. We found that the
Roper-like resonances in the multi-strangeness sector have large decay widths
bearing resemblances to their siblings in light and heavy baryon sectors. In
addition, we obtained the decay ratio for the $\Omega(2012)$ as
$\Gamma{(\Omega\to \Xi \bar{K} \pi)} / \Gamma{(\Omega\to \Xi \bar{K})}=4.5\%$,
which is consistent with the experimental data when $J^P=3/2^-$ is assigned.
This observation holds the possibility that the $\Omega(2012)$ could naturally
be explained as a three-quark state in the quark model. The decays of other
low-lying $\Xi$ and $\Omega$ resonances are systematically analyzed, which
would be useful to unveil the structure of these resonances in future
experiments.",2201.10427v1
2022-02-09,Weak pion-production and the second resonance region,"In this work we report the calculation of the total cross section for
pion-production by the dispersion of neutrinos on nucleons. We use a consistent
formalism for the intermediate resonance states of spin $3/2$ , taking care on
the conditions imposed by the invariance on contact transformations and using
the Sachs parametrization for the form factors. In addition, we incorporate
states in the second resonance region up to 1.6 GeV and implement different
approaches for all the dressed resonance propagators. In addition to the
$\Delta$(1232), we include the N$^*$(1440),N$^*$(1535)and N$^*$(1520) resonance
contributions, and it is shown that this inclusion improve the description of
the total cross section regards a model where only the $\Delta$(1230) resonance
is considered. Also results for antineutrinos are properly described.",2202.04760v1
2022-03-15,On-chip ultra-compact hexagonal boron nitride topological ring-resonator in visible region,"Ultra-compact topological ring-resonators with chirality are important
devices for quantum optics. However, there are limited demonstrations of chiral
resonators, especially in the visible region. We proposed a topological
photonic ring-resonator based on hexagonal boron nitride (hBN) valley photonic
crystal (VPC). The spin-valley locking effect in VPC allows achieving robust
unidirectional transmission of edge states in the visible region (600 nm-650
nm). As a result, a high quality factor (679.3) with a free spectral range of
15.2 nm in the visible region can be achieved in a hBN all-pass filter with a
compact size. In addition, we investigated the transmission properties of hBN
ring-resonators with different shapes and combinations, confirming the
flexibility of designing topological ring-resonators based on this principle.
This design can be readily integrated with quantum photonic chips for broad
applications.",2203.07602v1
2023-02-28,Deeply-virtual Compton process $e^- N \to e^- γπN$ to study nucleon to resonance transitions,"We study the deeply-virtual Compton scattering (DVCS) process $e^- N \to e^-
\gamma \pi N$ involving the transition between a nucleon and a nucleon
resonance in the $\pi N$ system, within the framework of generalized parton
distributions (GPDs). For the four lowest-lying nucleon resonances,
$\Delta(1232)$, $P_{11}(1440)$, $D_{13}(1520)$, and $S_{11}(1535)$, we express
the DVCS amplitude in the Bjorken limit in terms of corresponding
nucleon-to-resonance GPDs. Building upon the knowledge of the well studied
electromagnetic nucleon-to-resonance transition form factors, which map the
quark charge densities in transverse position space, the corresponding GPDs
will open the prospect to also access the longitudinal momentum distributions
of quarks in the transition. We provide estimates for cross sections and
beam-spin asymmetries in the first and second $\pi N$ resonance regions in the
kinematics of forthcoming CLAS12 data from Jefferson Lab.",2303.00119v1
2023-05-02,Combined effect of mutually frequency-detuned strong and weak drives on a two-level system: Envelope of the Rabi oscillations,"Near-resonant ac-drive acting on a two-level system induces the Rabi
oscillations of the level occupations. It is shown that additional weak drive
properly frequency-detuned from the primary drive causes a resonant response.
This response manifests itself in the emergence of the envelope of the
oscillations. At resonance, the inverse period of the envelope is proportional
to the amplitude of the weak drive. The resonant condition reads: difference of
frequencies between the two drives is equal to the ac-splitting of quasilevels
in the field of the strong drive. Technically, the resonance can be inferred
from the analogy between the equations for the time-evolution of the spin
amplitude and the Mathieu equation, which describes e.g. the parametric
resonance.",2305.01136v1
2001-10-15,Persistent Currents in Charge-density Wave Systems,"The inductive exchange of carriers between closed Fermi surface sections
subject to Landau quantization and open Fermi surface sections subject to
charge-density wave (or spin-density wave) formation is shown to give rise to
persistent currents. This mechanism may explain recent experimental data in
certain organic conductors in high magnetic fields.",0110278v1
2003-02-16,New Zero-Resistance States in Heterostructures: Anderson-Brinkman-Phillips Charge Density Waves and New States,"Recently, observed zero-resistance states are interpreted by
Anderson-Brinkman and Phillips as charge density waves. We point out the
existence of charge-density waves, superconducting states and new states
including a state of zero charge and finite spin.",0302320v1
2006-05-02,Waves in the Griffiths-Podolsky Metric,"Perturbations form an important section of black hole analyses. This paper
deals with the effect of perturbations as in the delineation of waves that
occur. It makes use of the spin coefficients from [3] to represent the general
equations of waves in an accelerating black hole proposed in [2].",0605020v2
2007-01-23,Spin Angular Momentum Imparted by Gravitational Waves,"Following the demonstration that gravitational waves impart linear momentum,
it is argued that if they are polarized they should impart angular momentum to
appropriately placed 'test rods' in their path. A general formula for this
angular momentum is obtained and used to provide expressions for the angular
momentum imparted by plane and cylindrical gravitational waves.",0701126v1
2007-03-01,Localized Asymmetric Atomic Matter Waves in Two-Component Bose-Einstein Condensates Coupled with Two Photon Microwave Field,"We investigate localized atomic matter waves in two-component Bose-Einstein
condensates coupled by the two photon microwave field. Interestingly, the
oscillations of localized atomic matter waves will gradually decay and finally
become non-oscillating behavior even if existing coupling field. In particular,
atom numbers occupied in two different hyperfine spin states will appear
asymmetric occupations after some time evolution.",0703001v1
2006-06-29,Quantum wave equations and non-radiating electromagnetic sources,"A connection between classical non-radiating sources and free-particle wave
equations in quantum mechanics is rigorously made. It is proven that
free-particle wave equations for all spins have currents which can be defined
which are non-radiating electromagnetic sources. It is also proven that the
advanced and retarded fields are exactly equal for these sources. Implications
of these results are discussed.",0606245v2
2017-06-06,Driven spin wave modes in XY ferromagnet: Nonequilibrium phase transition,"The dynamical responses of XY ferromagnet driven by linearly polarised
propagating and standing magnetic field wave have been studied by Monte Carlo
simulation in three dimensions. In the case of propagating magnetic field wave
(with specified amplitude, frequency and the wavelength), the low temperature
dynamical mode is a propagating spin wave and the system becomes structureless
(or random) in the high temperature. A dynamical symmetry breaking phase
transition is observed at a finite (nonzero) temperature. This symmetry
breaking is confirmed by studying the statistical distribution of the angle of
the spin vector. The dynamic nonequilibrium transition temperature was found to
decrease as the amplitude of the propagating magnetic field wave increased. A
comprehensive phase boundary is drawn in the plane formed by temperature and
amplitude of propagating field wave. The phase boundary was observed to shrink
(in the low temperature side) for longer wavelength of the propagating magnetic
wave. In the case of standing magnetic field wave, the low temperature
excitation is a standing spin wave which becomes structureless (or random) in
the high temperature. Here also, like the case of propagating magnetic wave, a
dynamical symmetry breaking nonequilibrium phase transition was observed. A
comprehensive phase boundary is drawn. Unlike the case of propagating magnetic
wave, the phase boundary does not show any systematic variation with the
wavelength of the standing magnetic field wave. In the limit of vanishingly
small amplitude of the field, the phase boundaries approach the recent Monte
Carlo estimate of equilibrium transition temperature.",1706.01619v6
2021-01-30,Pair density wave solution for self-consistent model,"In the t-U-V Hubbard model on the square lattice we found self-consistent
analytic solution for the ground state with coexisting d-wave symmetric bond
ordered pair density wave (PDW) and spin (SDW) or charge (CDW) density waves,
as observed in some high-temperature superconductors. In particular, the
solution gives the same periodicity for CDW and PDW, and a pseudogap in the
fermi-excitation spectrum.",2102.00144v1
2019-09-08,Holographic charge density wave from D2-D8,"We have considered D2-D8 model and obtain a numerical solution that exhibits
spatially modulated phases corresponding to a charge density wave and a spin
density wave. We have analysed behavior of the free energy density for
different values of the chemical potential and the magnetic field.",1909.03458v2
2021-12-25,Relativistic electron wave packets featuring persistent quantum backflow,"Closed-form, normalizable solutions of Dirac's equation propagating within a
semi-infinite cylindrical waveguide are obtained in terms of ordinary and
modified Bessel functions. These relativistic wave packets induce quantum
backflow on a cross-section of the cylinder at practically any distance along
the waveguide, becoming spin-polarized in the nonrelativistic limit. The
predicted backflow is stable in time and is manifest regardless of the initial
wave function.",2112.13180v1
2022-12-09,Measurement-Induced State Transitions in a Superconducting Qubit: Within the Rotating Wave Approximation,"Superconducting qubits typically use a dispersive readout scheme, where a
resonator is coupled to a qubit such that its frequency is qubit-state
dependent. Measurement is performed by driving the resonator, where the
transmitted resonator field yields information about the resonator frequency
and thus the qubit state. Ideally, we could use arbitrarily strong resonator
drives to achieve a target signal-to-noise ratio in the shortest possible time.
However, experiments have shown that when the average resonator photon number
exceeds a certain threshold, the qubit is excited out of its computational
subspace in a process we refer to as a measurement-induced state transition
(MIST). These transitions degrade readout fidelity, and constitute leakage
which precludes further operation of the qubit in, for example, error
correction. Here we study these transitions experimentally with a transmon
qubit by measuring their dependence on qubit frequency, average resonator
photon number, and qubit state, in the regime where the resonator frequency is
lower than the qubit frequency. We observe signatures of resonant transitions
between levels in the coupled qubit-resonator system that exhibit noisy
behavior when measured repeatedly in time. We provide a semi-classical model of
these transitions based on the rotating wave approximation and use it to
predict the onset of state transitions in our experiments. Our results suggest
the transmon is excited to levels near the top of its cosine potential
following a state transition, where the charge dispersion of higher transmon
levels explains the observed noisy behavior of state transitions. Moreover, we
show that occupation in these higher energy levels poses a major challenge for
fast qubit reset.",2212.05097v2
2023-03-20,Enhanced Blackhole mergers in AGN discs due to Precession induced resonances,"Recent studies have shown that AGN discs can host sources of gravitational
waves. Compact binaries can form and merge in AGN discs through their
interactions with the gas and other compact objects in the disc. It is also
possible for the binaries to shorten the merging timescale due to eccentricity
excitation caused by perturbations from the supermassive blackhole (SMBH). In
this paper we focus on effects due to precession-induced (eviction-like)
resonances, where nodal and apsidal precession rates of the binary is
commensurable with the mean motion of the binary around the SMBH. We focus on
intermediate mass black hole (IMBH)-stellar mass black hole (SBH) binaries, and
consider binary orbit inclined from the circum-IMBH disk which leads to the
orbital $J_2$ precession. We show that if a binary is captured in these
resonances and is migrating towards the companion, it can undergo large
eccentricity and inclination variations. We derive analytical expressions for
the location of fixed points, libration timescale and width for these
resonances, and identified two resonances in the near coplanar regime (the
evection and eviction resonances) as well as two resonances in the near polar
regime that can lead to mergers. We also derive analytical expressions for the
maximum eccentricity that a migrating binary can achieve for given initial
conditions. Specifically, the maximum eccentricity can reach 0.9 when captured
in these resonances before orbital decay due to gravitational wave emission
dominates, and the capture is only possible for slow migration ($\sim 10$ Myr)
2-3 order of magnitude longer than the resonance libration timescale. We also
show that capture into multiple resonances is possible, and can further excite
eccentricities.",2303.12539v2
2010-04-28,Bar-mode instability of rapidly spinning black hole in higher dimensions: Numerical simulation in general relativity,"Numerical-relativity simulation is performed for rapidly spinning black holes
(BHs) in a higher-dimensional spacetime of special symmetries for the
dimensionality $6 \leq d \leq 8$. We find that higher-dimensional BHs, spinning
rapidly enough, are dynamically unstable against nonaxisymmetric bar-mode
deformation and spontaneously emit gravitational waves, irrespective of $d$ as
in the case $d=5$ \cite{SY09}. The critical values of a nondimensional spin
parameter for the onset of the instability are $q:=a/\mu^{1/(d-3)} \approx
0.74$ for $d=6$, $\approx 0.73$ for $d=7$, and $\approx 0.77$ for $d=8$ where
$\mu$ and $a$ are mass and spin parameters. Black holes with a spin smaller
than these critical values ($q_{\rm crit}$) appear to be dynamically stable for
any perturbation. Longterm simulations for the unstable BHs are also performed
for $d=6$ and 7. We find that they spin down as a result of gravitational-wave
emission and subsequently settle to a stable stationary BH of a spin smaller
than $q_{\rm crit}$. For more rapidly spinning unstable BHs, the timescale, for
which the new state is reached, is shorter and fraction of the spin-down is
larger. Our findings imply that a highly rapidly spinning BH with $q > q_{\rm
crit}$ cannot be a stationary product in the particle accelerators, even if it
would be formed as a consequence of a TeV-gravity hypothesis. Its implications
for the phenomenology of a mini BH are discussed.",1004.4970v1
2013-06-20,"Magnetic orders, excitations, and phase transitions in Fe_1+yTe","We study the magnetic properties of Fe_1+y Te, a parent compound of the
iron-based high-temperature superconductors. Motivated by recent neutron
scattering experiments, we show that a spin-1 exchange model, supplemented by a
single-ion spin anisotropy, accounts well for the experimentally observed low
temperature magnetic phase diagram, that exhibits a commensurate bicollinear
order at low Fe dopings (y < 0.12) and an incommensurate spin-spiral order at
high Fe dopings (y > 0.12). We suggest that the commensurate-incommensurate
transition at y = 0.12 is due to the competition between the exchange
interaction and the local spin anisotropy. At low Fe dopings, the single-ion
spin anisotropy is strong and pins the spins along the easy axis, which,
together with the spatially anisotropic exchanges, induces a unusual
bicollinear commensurate magnetic order. The low-energy spin-wave excitation is
gapped due to the explict breaking of spin-rotational symmetry by the local
spin anisotropy. At high Fe dopings, the single-ion anisotropy is weak, and the
exchange favors an incommensurate coplanar state. The incommensurate magnetic
wavevector averages out the spin anisotropy so that a gapless low-energy
spin-wave excitation is obtained. We also analyze the low-energy hydrodynamic
model and use it to describe the magneto-structural transition and the static
and dynamical spin structure factors across the magnetic ordering transitions.",1306.4730v2
2016-09-22,Magnetization oscillations and waves driven by pure spin currents,"Recent advances in the studies of pure spin currents - flows of angular
momentum (spin) not accompanied by the electric currents - have opened new
horizons for the emerging technologies based on the electron's spin degree of
freedom, such as spintronics and magnonics. The main advantage of pure spin
current, as compared to the spin-polarized electric current, is the possibility
to exert spin transfer torque on the magnetization in thin magnetic films
without electrical current flow through the material. In addition to minimizing
Joule heating and electromigration effects, this characteristic enables the
implementation of spin torque devices based on the low-loss insulating magnetic
materials, and offers an unprecedented geometric flexibility. Here we review
the recent experimental achievements in investigations of magnetization
oscillations excited by pure spin currents in different magnetic nanosystems
based on metallic and insulating magnetic materials. We discuss the spectral
properties of spin-current nano-oscillators, and relate them to the spatial
characteristics of the excited dynamic magnetic modes determined by the
spatially-resolved measurements. We also show that these systems support
locking of the oscillations to external microwave signals, as well as their
mutual synchronization, and can be used as efficient nanoscale sources of
propagating spin waves.",1609.06899v1
2018-06-19,Spin-Precessing Black Hole Binaries in Dynamical Chern-Simons Gravity,"Gravitational waves from spin-precessing binaries exhibit amplitude
oscillations that provide an invaluable method to extract the spins of the
inspiraling compact objects. The spin-spin and spin-orbit interactions that
cause this effect are sensitive to the fundamental nature of gravity, which
will allow us to constrain modified theories of gravity using gravitational
wave observations of precessing binaries. We here consider precessing black
hole binaries in dynamical Chern-Simons gravity, an effective theory of gravity
that enhances parity violating interactions. We model the black holes as
modified point particles using effective field theory, and derive the
spin-precession equations for a binary system by working within the
post-Newtonian formalism. We find that the spin-spin and quadrupole-monopole
interactions of General Relativity are modified due to an interaction between
the scalar dipoles of the two black holes and the modified black hole
quadrupole as a result of the violation of the no hair theorems. These
modifications enter the precession equations at leading post-Newtonian order.
We further show that these precession equations admit seven constants of motion
when neglecting radiation reaction, with only the mass-weighted effective spin
being modified from General Relativity. We discuss how these may be used to
reduce the precession equations to quadrature and the possibility of
constructing analytic Fourier domain waveforms for generic spin-precessing
binaries in dCS gravity.",1806.07431v2
2021-03-23,Spin excitations in metallic kagome lattice FeSn and CoSn,"In two-dimensional (2D) metallic kagome lattice materials, destructive
interference of electronic hopping pathways around the kagome bracket can
produce nearly localized electrons, and thus electronic bands that are flat in
momentum space. When ferromagnetic order breaks the degeneracy of the
electronic bands and splits them into the spin-up majority and spin-down
minority electronic bands, quasiparticle excitations between the spin-up and
spin-down flat bands should form a narrow localized spin-excitation Stoner
continuum coexisting with well-defined spin waves in the long wavelengths. Here
we report inelastic neutron scattering studies of spin excitations in 2D
metallic Kagome lattice antiferromagnetic FeSn and paramagnetic CoSn, where
angle resolved photoemission spectroscopy experiments found spin-polarized and
nonpolarized flat bands, respectively, below the Fermi level. Although our
initial measurements on FeSn indeed reveal well-defined spin waves extending
well above 140 meV coexisting with a flat excitation at 170 meV, subsequent
experiments on CoSn indicate that the flat mode actually arises mostly from
hydrocarbon scattering of the CYTOP-M commonly used to glue the samples to
aluminum holder. Therefore, our results established the evolution of spin
excitations in FeSn and CoSn, and identified an anomalous flat mode that has
been overlooked by the neutron scattering community for the past 20 years.",2103.12873v3
2021-11-04,Apples and Oranges: Comparing black holes in X-ray binaries and gravitational-wave sources,"The component black holes (BHs) observed in gravitational-wave (GW) binary
black hole (BBH) events tend to be more massive and slower spinning than those
observed in black hole X-ray binaries (BH-XRBs). Without modeling their
evolutionary histories, we investigate whether these apparent tensions in the
BH populations can be explained by GW observational selection effects alone. We
find that this is indeed the case for the discrepancy between BH masses in BBHs
and the observed high-mass X-ray binaries (HMXBs), when we account for
statistical uncertainty from the small sample size of just three HMXBs. On the
other hand, the BHs in observed low-mass X-ray binaries (LMXBs) are
significantly lighter than the astrophysical BBH population, but this may just
be due to a correlation between component masses in a binary system. Given
their light stellar companions, we expect light BHs in LMXBs. The observed
spins in HMXBs and LMXBs, however, are in tension with the inferred BBH spin
distribution at the $>99.9\%$ level. We discuss possible scenarios behind the
significantly larger spins in observed BH-XRBs. One possibility is that a small
subpopulation (conservatively $<30\%$) of BBHs have rapidly spinning primary
components, indicating that they may have followed a similar evolutionary
pathway to the observed HMXBs. In LMXBs, it has been suggested that BHs can
spin up by accretion. If LMXB natal spins follow the BBH spin distribution, we
find LMXBs must gain an average dimensionless spin of $0.47^{+0.10}_{-0.11}$,
but if their natal spins follow the observed HMXB spins, the average spinup
must be $<0.03$.",2111.02935v2
2024-02-23,Spin Doctors: How to diagnose a hierarchical merger origin,"Gravitational-wave observations provide the unique opportunity of studying
black hole formation channels and histories -- but only if we can identify
their origin. One such formation mechanism is the dynamical synthesis of black
hole binaries in dense stellar systems. Given the expected isotropic
distribution of component spins of binary black hole in gas-free dynamical
environments, the presence of anti-aligned or in-plane spins with respect to
the orbital angular momentum is considered a tell-tale sign of a merger's
dynamical origin. Even in the scenario where birth spins of black holes are
low, hierarchical mergers attain large component spins due to the orbital
angular momentum of the prior merger. However, measuring such spin
configurations is difficult. Here, we quantify the efficacy of the spin
parameters encoding aligned-spin ($\chieff$) and in-plane spin ($\chip$) at
classifying such hierarchical systems. Using Monte Carlo cluster simulations to
generate a realistic distribution of hierarchical merger parameters from
globular clusters, we can infer mergers' $\chieff$ and $\chip$. The cluster
populations are simulated using Advanced LIGO-Virgo sensitivity during the
detector network's third observing period and projections for design
sensitivity. Using a ""likelihood-ratio""-based statistic, we find that $\sim2\%$
of the recovered population by the current gravitational-wave detector network
has a statistically significant $\chip$ measurement, whereas no $\chieff$
measurement was capable of confidently determining a system to be anti-aligned
with the orbital angular momentum at current detector sensitivities. These
results indicate that measuring spin-precession through $\chip$ is a more
detectable signature of a hierarchical mergers and dynamical formation than
anti-aligned spins.",2402.15066v1
2018-11-23,Weakly non-linear transient waves on a shear current: Ring waves and skewed Langmuir rolls,"We investigate the weakly nonlinear dynamics of transient gravity waves at
infinite depth under the influence of a shear current varying linearly with
depth. An analytical solution is permitted via integration of the Euler
equations. Although similar problems were investigated in the 1960's and 70's
for special cases of resonance, this is to our knowledge the first general wave
interaction (mode coupling) solution derived to second order with a shear
current present. Wave interactions are integrable in a spectral convolution to
yield the second order dynamics of initial value problems.
  To second order, irrotational wave dynamics interacts with the background
vorticity field in a way that creates new vortex structures. A notable example
is the large parallel vortices which drive Langmuir circulation as oblique
plane waves interact with an ocean current. We also investigate the effect on
wave pairs which are misaligned with the shear current. In contrast to a
conjecture by Leibovich (1983) we find similar, but skewed, vortex structures
in every case except when the mean wave direction is perpendicular to the
direction of the current. Similar nonlinear wave-shear interactions are found
to also generate near-field vortex structures in the Cauchy-Poisson problem
with an initial surface elevation. These interactions create further groups of
dispersive ring waves in addition to those present in linear theory.
  The second order solution is derived in a general manner which accommodates
any initial condition through mode coupling over a continuous wave spectrum. It
is therefore applicable to a range of problems including special cases of
resonance. As a by--product of the general theory, a simple expression for the
Stokes drift due to a monochromatic wave propagating at oblique angle with a
current of uniform vorticity is derived, for the first time to our knowledge.",1811.09396v1
2020-03-21,Narrowband large amplitude whistler-mode waves in the solar wind and their association with electrons: STEREO waveform capture observations,"Large amplitude whistler waves at frequencies of 0.2 to 0.4 times electron
cyclotron frequency are frequently observed in the solar wind. The waves are
obliquely propagating close to the resonance cone, with significant electric
fields parallel to the background magnetic field, enabling strong interactions
with electrons. Propagation angles are distinctly different from whistlers
usually observed in the solar wind, and amplitudes are significantly larger.
Waves occur most often in association with stream interaction regions (SIRs),
and are often close-packed. 68 percent of the 54 SIRs had narrowband whistler
groups; 33 percent of the nine interplanetary coronal mass ejections had
coherent groups. Although wave occurrence as a function of the electron
temperature anisotropy and parallel beta is constrained by the thresholds for
the whistler temperature anisotropy and firehose instabilities, neither is
consistent with observed wave properties. We show for the first time that
comparisons of wave data to thresholds for the electron beam driven instability
(beam speed greater than twice the electron Alfven speed) and to the whistler
heat flux fan instability indicate that either might destabilize the narrowband
waves. In contrast, the less coherent waves, on average, are associated with
zero or near zero heat flux and much higher electron Alfven speeds, without
higher energy beams. This suggests that the less coherent waves may be more
effective in regulating the electron heat flux, or that the scattering and
energization of solar wind electrons by the narrowband waves results in
broadening of the waves. The highly oblique propagation and large amplitudes of
both the narrowband and less coherent whistlers enable resonant interactions
with electrons over a broad energy range, and, unlike parallel whistlers does
not require that the electrons and waves counter-propagate.",2003.09659v2
2021-02-26,Microscopic analysis of low-energy spin and orbital magnetic dipole excitations in deformed nuclei,"A low-energy magnetic dipole $(M1)$ spin-scissors resonance (SSR) located
just below the ordinary orbital scissors resonance (OSR) was recently predicted
in deformed nuclei within the Wigner Function Moments (WFM) approach. We
analyze this prediction using fully self-consistent Skyrme Quasiparticle Random
Phase Approximation (QRPA) method. Skyrme forces SkM*, SVbas and SG2 are
implemented to explore SSR and OSR in $^{160,162,164}$Dy and $^{232}$Th.
Accuracy of the method is justified by a good description of M1 spin-flip giant
resonance. The calculations show that isotopes $^{160,162,164}$Dy indeed have
at 1.5-2.4 MeV (below OSR) $I^{\pi}K=1^+1$ states with a large $M1$ spin
strength ($K$ is the projection of the total nuclear moment to the symmetry
z-axis). These states are almost fully exhausted by $pp[411\uparrow,
411\downarrow]$ and $nn[521\uparrow, 521\downarrow]$ spin-flip configurations
corresponding to $pp[2d_{3/2}, 2d_{5/2}]$ and $nn[2f_{5/2}, 2f_{7/2}]$
structures in the spherical limit. So the predicted SSR is actually reduced to
low-orbital (l=2,3) spin-flip states. Following our analysis and in
contradiction with WFM spin-scissors picture, deformation is not the principle
origin of the low-energy spin $M1$ states but only a factor affecting their
features. The spin and orbital strengths are generally mixed and exhibit the
interference: weak destructive in SSR range and strong constructive in OSR
range. In $^{232}$Th, the $M1$ spin strength is found very small. Two groups of
$I^{\pi}=1^+$ states observed experimentally at 2.4-4 MeV in $^{160,162,164}$Dy
and at 2-4 MeV in $^{232}$Th are mainly explained by fragmentation of the
orbital strength. Distributions of nuclear currents in QRPA states partly
correspond to the isovector orbital-scissors flow but not to spin-scissors one.",2102.13580v2
2010-03-25,Spin superfluidity and magnon BEC,"The spin superfluidity -- superfluidity in the magnetic subsystem of a
condensed matter - is manifested as the spontaneous phase-coherent precession
of spins first discovered in 1984 in 3He-B. This superfluid current of spins -
spin supercurrent - is one more representative of superfluid currents known or
discussed in other systems, such as the superfluid current of mass and atoms in
superfluid 4He; superfluid current of electric charge in superconductors;
superfluid current of hypercharge in Standard Model of particle physics;
superfluid baryonic current and current of chiral charge in quark matter; etc.
Spin superfluidity can be described in terms of the Bose condensation of spin
waves - magnons. We discuss different phases of magnon superfluidity, including
those in magnetic trap; and signatures of magnons superfluidity: (i) spin
supercurrent, which transports the magnetization on a macroscopic distance more
than 1 cm long; (ii) spin current Josephson effect which shows interference
between two condensates; (iii) spin current vortex - a topological defect which
is an analog of a quantized vortex in superfluids, of an Abrikosov vortex in
superconductors, and cosmic strings in relativistic theories; (iv) Goldstone
modes related to the broken U(1) symmetry - phonons in the spin-superfluid
magnon gas; etc. We also touch the topic of spin supercurrent in general
including spin Hall and intrinsic quantum spin Hall effects.",1003.4889v3
2018-09-24,Quantum spin-transfer torque induced nonclassical magnetization dynamics and electron-magnetization entanglement,"The standard spin-transfer torque (STT)---where spin-polarized current drives
dynamics of magnetization viewed as a classical vector---requires
noncollinearity between electron spins carried by the current and magnetization
of a ferromagnetic layer. However, recent experiments [A. Zholud et al., Phys.
Rev. Lett. 119, 257201 (2017)] observing magnetization dynamics in spin valves
at cryogenic temperatures, even when electron spin is collinear to
magnetization, point at overlooked quantum effects in STT which can lead to
highly nonclassical magnetization states. Using fully quantum many-body
treatment, where an electron injected as spin-polarized wave packet interacts
with local spins comprising the anisotropic quantum Heisenberg ferromagnetic
chain, we define quantum STT as any time evolution of local spins due to
initial many-body state not being an eigenstate of electron+local-spins system.
For time evolution caused by injected spin-down electron scattering off local
up-spins, entanglement between electron subsystem and local spins subsystem
takes place leading to decoherence and, therefore, shrinking of the total
magnetization but without rotation from its initial orientation which explains
the experiments. Furthermore, the same processes---entanglement and thereby
induced decoherence---are present also in standard noncollinear geometry,
together with the usual magnetization rotation. This is because STT in quantum
many-body picture is caused only by electron spin-down factor state, and the
only difference between collinear and noncollinear geometries is in relative
size of the contribution of initial many-body state containing such factor
state to superpositions of separable many-body quantum states generated during
time evolution.",1809.09090v1
2019-05-27,Spin-Cooling of the Motion of a Trapped Diamond,"Observing and controlling macroscopic quantum systems has long been a driving
force in research on quantum physics. In this endeavor, strong coupling between
individual quantum systems and mechanical oscillators is being actively
pursued. While both read-out of mechanical motion using coherent control of
spin systems and single spin read-out using pristine oscillators have been
demonstrated, temperature control of the motion of a macroscopic object using
long-lived electronic spins has not been reported. Here, we observe both a
spin-dependent torque and spin-cooling of the motion of a trapped microdiamond.
Using a combination of microwave and laser excitation enables the spin of
nitrogen-vacancy centers to act on the diamond orientation and to cool the
diamond libration via a dynamical back-action. Further, driving the system in
the non-linear regime, we demonstrate bistability and self-sustained coherent
oscillations stimulated by the spin-mechanical coupling, which offers prospects
for spin-driven generation of non-classical states of motion. Such a levitating
diamond operated as a compass with controlled dissipation has implications in
high-precision torque sensing, emulation of the spin-boson problem and probing
of quantum phase transitions. In the single spin limit and employing ultra-pure
nano-diamonds, it will allow quantum non-demolition read-out of the spin of
nitrogen-vacancy centers under ambient conditions, deterministic entanglement
between distant individual spins and matter-wave interferometry.",1905.11509v2
2019-10-16,"Thermal Hall effect, spin Nernst effect, and spin density induced by thermal gradient in collinear ferrimagnets from magnon-phonon interaction","We theoretically study the intrinsic thermal Hall and spin Nernst effect in
collinear ferrimagnets on a honeycomb lattice with broken inversion symmetry.
The broken inversion symmetry allows in-plane Dzyaloshinskii-Moriya interaction
between the nearest neighbors, which does not affect the magnon spectrum in the
linear spin wave theory. However, the Dzyaloshinskii-Moriya interaction can
induce large Berry curvature in the magnetoelastic excitation spectrum through
the magnon-phonon interaction to produce thermal Hall current. Furthermore, we
find that the magnetoelastic excitations transport spin, which is inherited
from the magnon bands. Therefore, the thermal Hall current is accompanied by
spin Nernst current. Because the magnon-phonon interaction does not conserve
the spin, we also study the spin density induced by thermal gradient in the
presence of magnon-phonon interaction. We find that the intrinsic part of the
spin density shows no asymmetric spin accumulation near the boundary of the
system having a stripe geometry. However, because of the magnon-phonon
interaction, we find nonzero total spin density in the system having armchair
edges. The extrinsic part of the spin density, on the other hand, shows
asymmetric spin accumulation near the boundary for both armchair and zigzag
edges because of the magnon-phonon interaction. In addition, we find nonzero
total spin density in the system having zigzag edge.",1910.07206v2
2021-11-07,A correctly scaling rigorously spin-adapted and spin-complete open-shell CCSD implementation for arbitrary high-spin states,"In this paper, we report on a correctly scaling novel coupled cluster singles
and doubles (CCSD) implementation for arbitrary high-spin open-shell states.
The chosen cluster operator is completely spin-free, i.e. employs spatial
substitutions only. It is composed of our recently developed L\""owdin-type
operators (doi: 10.1063/5.0026762), which ensure (1) spin completeness and (2)
spin adaption i.e. spin purity of the CC wave function. In contrast to the
proof-of-concept matrix-representation-based implementation presented there,
the present implementation relies on second quantization and factorized tensor
contractions. The generated singles and doubles operators are embedded in an
equation generation engine. In the latter, Wick's theorem is used to derive
prefactors arising from spin integration directly from the spin-free full
contraction patterns. The obtained Wick terms composed of products of Kronecker
deltas are represented by special non-antisymmetrized Goldstone diagrams.
Identical (redundant) diagrams are identified by solving the underlying graph
isomorphism problem. All non-redundant graphs are then automatically translated
to locally -- one term at a time -- factorized tensor contractions. Finally,
the spin-adapted and spin-complete (SASC) CCS and CCSD variants are applied to
a set of small molecular test systems. Both correlation energies and amplitude
norms hint towards a reasonable convergence of the SASC-CCSD method for a BCH
series truncation of order four. In comparison to spin orbital CCSD, SASC-CCSD
leads to slightly improved correlation energies with differences of up to 0.886
mE_H (0.98% w.r.t. spin orbital CCSD(T)).",2111.04186v1
2023-10-23,Microscopic theory of spin Seebeck effect in antiferromagnets,"We develop a microscopic theory for the spin Seebeck effect (SSE) in N\'eel
and canted phases of antiferromagnetic insulators. We calculate the DC spin
current tunneling from the antiferromagnet to an attached metal, incorporating
the spin-wave theory and the non-equilibrium Green's function approach. Our
result shows a sign change of the spin current at the spin-flop phase
transition between N\'eel and canted phases, which is in agreement with a
recent experiment for the SSE of $\rm Cr_2O_3$ in a semi-quantitative level.
The sign change can be interpreted from the argument based on the density of
states of up- and down-spin magnons, which is related to the polarized-neutron
scattering spectra. The theory also demonstrates that the spin current in the
N\'eel phase is governed by the magnon correlation, while that in the canted
phase consists of two parts: Contributions from not only the magnon dynamics
but also the static transverse magnetization. This result leads to a prediction
that at sufficiently low temperatures, the spin current non-monotonically
changes as a function of magnetic field in the canted phase. Towards a more
unified understanding of the SSE in antiferromagnets, we further discuss some
missing links of theories of SSE: Interface properties, effects of the
transverse spin moment in the canted phase, the spin-orbit coupling in the
metal, etc. Finally, we compare the SSE of antiferromagnets with those of
different magnetic phases such as ferromagnets, ferrimagnets, an
one-dimensional spin liquid, a spin-nematic liquid, and a spin-Peierls
(dimerized) phase.",2310.15292v2
2005-09-06,Rigorous analysis of extremely asymmetrical scattering of electromagnetic waves in slanted periodic gratings,"Extremely asymmetrical scattering (EAS) is a new type of Bragg scattering in
thick, slanted, periodic gratings. It is realised when the scattered wave
propagates parallel to the front boundary of the grating. Its most important
feature is the strong resonant increase in the scattered wave amplitude
compared to the amplitude of the incident wave: the smaller the grating
amplitude, the larger the amplitude of the scattered wave. In this paper,
rigorous numerical analysis of EAS is carried out by means of the enhanced
T-matrix algorithm. This includes investigation of harmonic generation inside
and outside the grating, unusually strong edge effects, fast oscillations of
the incident wave amplitude in the grating, etc. Comparison with the previously
developed approximate theory is carried out. In particular, it is demonstrated
that the applicability conditions for the two-wave approximation in the case of
EAS are noticeably more restrictive than those for the conventional Bragg
scattering. At the same time, it is shown that the approximate theory is
usually highly accurate in terms of description of EAS in the most interesting
cases of scattering with strong resonant increase of the scattered wave
amplitude. Physical explanation of the predicted effects is presented.",0509042v2
2007-06-06,Coronal ion-cyclotron beam instabilities within the multi-fluid description,"Spectroscopic observations and theoretical models suggest resonant
wave-particle interactions, involving high-frequency ion-cyclotron waves, as
the principal mechanism for heating and accelerating ions in the open coronal
holes. However, the mechanism responsible for the generation of the
ion-cyclotron waves remains unclear. One possible scenario is that ion beams
originating from small-scale reconnection events can drive micro-instabilities
that constitute a possible source for the excitation of ion-cyclotron waves. In
order to study ion beam-driven electromagnetic instabilities, the multi-fluid
model in the low-beta coronal plasma is used. While neglecting the electron
inertia this model allows one to take into account ion-cyclotron wave effects
that are absent from the one-fluid MHD model. Realistic models of density and
temperature as well as a 2-D analytical magnetic field model are used to define
the background plasma in the open-field funnel region of a polar coronal hole.
Considering the WKB approximation, a Fourier plane-wave linear mode analysis is
employed in order to derive the dispersion relation. Ray-tracing theory is used
to compute the ray path of the unstable wave as well as the evolution of the
growth rate of the wave while propagating in the coronal funnel. We demonstrate
that, in typical coronal holes conditions and assuming realistic values of the
beam velocity, the free energy provided by the ion beam propagating parallel
the ambient field can drive micro-instabilities through resonant ion-cyclotron
excitation.",0706.0752v2
2014-09-25,Ultraslow Wave Nuclear Burning of Uranium-Plutonium Fissile Medium on Epithermal Neutrons,"For a fissile medium, originally consisting of uranium-238, the investigation
of fulfillment of the wave burning criterion in a wide range of neutron
energies is conducted for the first time, and a possibility of wave nuclear
burning not only in the region of fast neutrons, but also for cold, epithermal
and resonance ones is discovered for the first time.
  For the first time the results of the investigation of the Feoktistov
criterion fulfillment for a fissile medium, originally consisting of
uranium-238 dioxide with enrichments 4.38%, 2.00%, 1.00%, 0.71% and 0.50% with
respect to uranium-235, in the region of neutron energies 0.015-10.0eV are
presented. These results indicate a possibility of ultraslow wave
neutron-nuclear burning mode realization in the uranium-plutonium media,
originally (before the wave initiation by external neutron source) having
enrichments with respect to uranium-235, corresponding to the subcritical
state, in the regions of cold, thermal, epithermal and resonance neutrons.
  In order to validate the conclusions, based on the slow wave neutron-nuclear
burning criterion fulfillment depending on the neutron energy, the numerical
modeling of ultraslow wave neutron-nuclear burning of a natural uranium in the
epithermal region of neutron energies (0.1-7.0eV) was conducted for the first
time. The presented simulated results indicate the realization of the ultraslow
wave neutron-nuclear burning of the natural uranium for the epithermal
neutrons.",1409.7343v2
2016-04-22,Oscillating line source in a shear flow with a free surface: critical layer-like contributions,"The linearized water-wave radiation problem for an oscillating submerged line
source in an inviscid shear flow with a free surface is investigated
analytically at finite, constant depth in the presence of a shear flow varying
linearly with depth. The surface velocity is taken to be zero relative to the
oscillating source, so that Doppler effects are absent. The radiated wave out
from the source is calculated based on Euler's equation of motion with the
appropriate boundary and radiation conditions, and differs substantially from
the solution obtained by assuming potential flow. To wit, an additional wave is
found in the downstream direction in addition to the previously known
dispersive wave solutions; this wave is non-dispersive and we show how it is
the surface manifestation of a critical layer-like flow generated by the
combination of shear and mass flux at the source, passively advected with the
flow. As seen from a system moving at the fluid velocity at the source's depth,
streamlines form closed curves in a manner similar to Kelvin's cat's eye
vortices. A resonant frequency exists at which the critical wave resonates with
the downstream propagating wave, resulting in a downstream wave pattern
diverging linearly in amplitude away from the source.",1604.06672v1
2018-04-20,A Weakly Nonlinear Model for the Damping of Resonantly Forced Density Waves in Dense Planetary Rings,"In this paper we address the stability of resonantly forced density waves in
dense planetary rings.
  Already by Goldreich & Tremaine (1978) it has been argued that density waves
might be unstable, depending on the relationship between the ring's viscosity
and the surface mass density.
  In the recent paper Schmidt et al. (2016) we have pointed out that when -
within a fluid description of the ring dynamics - the criterion for viscous
overstability is satisfied, forced spiral density waves become unstable as
well.
  In this case, linear theory fails to describe the damping, but nonlinearity
of the underlying equations guarantees a finite amplitude and eventually a
damping of the wave.
  We apply the multiple scale formalism to derive a weakly nonlinear damping
relation from a hydrodynamical model.
  This relation describes the resonant excitation and nonlinear viscous damping
of spiral density waves in a vertically integrated fluid disk with density
dependent transport coefficients.
  The model consistently predicts density waves to be (linearly) unstable in a
ring region where the conditions for viscous overstability are met.
  Sufficiently far away from the Lindblad resonance, the surface mass density
perturbation is predicted to saturate to a constant value due to nonlinear
viscous damping.
  The wave's damping lengths of the model depend on certain input parameters,
such as the distance to the threshold for viscous overstability in parameter
space and the ground state surface mass density.",1804.07674v1
2023-05-08,Uncovering and experimental realization of multimodal 3D topological metamaterials for low-frequency and multiband elastic wave control,"Topological metamaterials unlock confined and robust elastic wave control in
mechanical structures. Recent breakthroughs have precipitated the development
of 3D topological mechanical metamaterials, which extend beyond the
conventional 1D and 2D metamaterials to facilitate extraordinary wave
manipulation along 2D planar and layer-dependent elastic waveguides. While
promising, significant research gaps exist that impede the practical
implementation of 3D topological metamaterials. The 3D topological
metamaterials studied thus far are constrained to function in single frequency
bandwidths that are typically in a high-frequency regime, and a comprehensive
experimental investigation remains elusive. In this paper, we address these
research gaps and advance the state of the art through the synthesis and
experimental realization of a 3D topological metamaterial that exploits
multimodal local resonance to enable low-frequency elastic wave control over
multiple distinct frequency bands. The proposed metamaterial is geometrically
configured to create multimodal local resonators whose frequency
characteristics govern the emergence of four unique low-frequency topological
states. Numerical simulations uncover how these topological states can be
employed to achieve polarization-, frequency-, and layer-dependent wave
manipulation in 3D structures. An experimental study results in the attainment
of complete wave fields that unambiguously illustrate 2D topological waveguides
and multi-polarized wave control in a physical testbed. The outcomes from this
work open the door for future research with 3D topological mechanical
metamaterials and reveal the applicability of the proposed metamaterial for
various wave control applications.",2305.04649v1
2006-09-08,Studies on Entanglement in Nuclear and Electron Spin Systems for Quantum Computing,"In this work, we have been working on the concept of quantum entanglement. At
first, we studied the theory of entanglement in its characterization and
measurement, introducing a new scheme for detection of entanglement. The new
approach links molecular-spin entities involving nuclear spins to quantum
computing as more appropriate physical systems of interest. Then, we continued
with the realization of entanglement in experiments. NMR has been the first
choice due to its well approved advantages for quantum computing. NMR, however,
has not been an appropriate system for demonstrating entangled states. Through
a mathematical proof, NMR with low spin polarization has been invalidated for
true implementations of non-local quantum algorithms, particularly supserdense
coding. The point is that high spin polarization is inevitably required to
acquire entanglement while in the current NMR it has been a formidable task to
get highly polarized nuclear spins. In order to acquire high spin polarization,
introducing electron spins can be much effective because of its
three-order-of-magnitude larger gyromagnetic ratio compared to nuclear spins.
Electron Nuclear DOuble Resonance (ENDOR) is spin manipulation technology that
enables us to deal with both electron and nuclear spins. Thus, in this context,
it can be more appropriate device for quantum computing. We emphasize that
(pseudo)entanglement and interconversion between the entangled states have been
realized with ENDOR on extremely stable organic molecular-spin entities. The
required experimental conditions to obtain true quantum entanglement are also
discussed. The appropriate entanglement witness for the corresponding ensemble
quantum computing is introduced and examined.",0609063v3
2007-11-09,Semiconductor Spintronics,"Spintronics refers commonly to phenomena in which the spin of electrons in a
solid state environment plays the determining role. In a more narrow sense
spintronics is an emerging research field of electronics: spintronics devices
are based on a spin control of electronics, or on an electrical and optical
control of spin or magnetism. This review presents selected themes of
semiconductor spintronics, introducing important concepts in spin transport,
spin injection, Silsbee-Johnson spin-charge coupling, and spindependent
tunneling, as well as spin relaxation and spin dynamics. The most fundamental
spin-dependent nteraction in nonmagnetic semiconductors is spin-orbit coupling.
Depending on the crystal symmetries of the material, as well as on the
structural properties of semiconductor based heterostructures, the spin-orbit
coupling takes on different functional forms, giving a nice playground of
effective spin-orbit Hamiltonians. The effective Hamiltonians for the most
relevant classes of materials and heterostructures are derived here from
realistic electronic band structure descriptions. Most semiconductor device
systems are still theoretical concepts, waiting for experimental
demonstrations. A review of selected proposed, and a few demonstrated devices
is presented, with detailed description of two important classes: magnetic
resonant tunnel structures and bipolar magnetic diodes and transistors. In most
cases the presentation is of tutorial style, introducing the essential
theoretical formalism at an accessible level, with case-study-like
illustrations of actual experimental results, as well as with brief reviews of
relevant recent achievements in the field.",0711.1461v1
2009-09-10,Dynamic spin-Hall effect and driven spin helix for linear spin-orbit interactions,"We derive boundary conditions for the electrically induced spin accumulation
in a finite, disordered 2D semiconductor channel. While for DC electric fields
these boundary conditions select spatially constant spin profiles equivalent to
a vanishing spin-Hall effect, we show that an in-plane ac electric field
results in a non-zero ac spin-Hall effect, i.e., it generates a spatially
non-uniform out-of-plane polarization even for linear intrinsic spin-orbit
interactions. Analyzing different geometries in [001] and [110]-grown quantum
wells, we find that although this out-of-plane polarization is typically
confined to within a few spin-orbit lengths from the channel edges, it is also
possible to generate spatially oscillating spin profiles which extend over the
whole channel. The latter is due to the excitation of a driven spin-helix mode
in the transverse direction of the channel. We show that while finite
frequencies suppress this mode, it can be amplified by a magnetic field tuned
to resonance with the frequency of the electric field. In this case, finite
size effects at equal strengths of Rashba- and Dresselhaus SOI lead to an
enhancement of the magnitude of this helix mode. We comment on the relation
between spin currents and boundary conditions.",0909.1892v2
2012-02-17,Electrical injection and detection of spin accumulation in Ge at room temperature,"We inject spin-polarized electrons from an Fe/MgO tunnel barrier contact into
n-type Ge(001) substrates with electron densities 2e16 < n < 8e17 cm-3, and
electrically detect the resulting spin accumulation using three-terminal Hanle
measurements. We observe significant spin accumulation in the Ge up to room
temperature. We observe precessional dephasing of the spin accumulation (the
Hanle effect) in an applied magnetic field for both forward and reverse bias
(spin extraction and injection), and determine spin lifetimes and corresponding
diffusion lengths for temperatures of 225 K to 300 K. The room temperature spin
lifetime increases from {\tau}s = 50 ps to 123 ps with decreasing electron
concentration, as expected from electron spin resonance work on bulk Ge. The
measured spin resistance-area product is in good agreement with values
predicted by theory for samples with carrier densities below the
metal-insulator transition (MIT), but 100x larger for samples above the MIT.
These data demonstrate that the spin accumulation measured occurs in the Ge,
although dopant-derived interface or band states may enhance the measured spin
voltage above the MIT. We estimate the polarization in the Ge to be on the
order of 1%.",1202.3994v1
2013-11-18,Manipulation of the nuclear spin ensemble in a quantum dot with chirped magnetic resonance pulses,"The nuclear spins in nanostructured semiconductors play a central role in
quantum applications. The nuclear spins represent a useful resource for
generating local magnetic fields but nuclear spin noise represents a major
source of dephasing for spin qubits. Controlling the nuclear spins enhances the
resource while suppressing the noise. NMR techniques are challenging: the group
III and V isotopes have large spins with widely different gyromagnetic ratios;
in strained material there are large atom-dependent quadrupole shifts; and
nanoscale NMR is hard to detect. We report NMR on 100,000 nuclear spins of a
quantum dot using chirped radiofrequency pulses. Following polarization, we
demonstrate a reversal of the nuclear spin. We can flip the nuclear spin back
and forth a hundred times.We demonstrate that chirped NMR is a powerful way of
determining the chemical composition, the initial nuclear spin temperatures and
quadrupole frequency distributions for all the main isotopes. The key
observation is a plateau in the NMR signal as a function of sweep rate: we
achieve inversion at the first quantum transition for all isotopes
simultaneously. These experiments represent a generic technique for
manipulating nanoscale inhomogeneous nuclear spin ensembles and open the way to
probe the coherence of such mesoscopic systems.",1311.4295v2
2015-04-29,Role of transparency of platinum-ferromagnet interface in determining intrinsic magnitude of spin Hall effect,"The spin Hall effect (SHE) converts charge current to pure spin currents in
orthogonal directions in materials that have significant spin-orbit
coupling.The efficiency of the conversion is described by the spin Hall Angle
(SHA). The SHA can most readily be inferred by using the generated spin
currents to excite or rotate the magnetization of ferromagnetic films or
nano-elements via spin-transfer torques.Some of the largest spin torque derived
spin Hall angles (ST-SHA) have been reported in platinum. Here we show, using
spin torque ferromagnetic resonance (ST-FMR) measurements, that the
transparency of the Pt-ferromagnet interface to the spin current plays a
central role in determining the magnitude of the ST-SHA. We measure a much
larger ST-SHA in Pt/cobalt (~0.11) compared to Pt/permalloy (~0.05) bilayers
when the interfaces are assumed to be completely transparent. Taking into
account the transparency of these interfaces, as derived from spin-mixing
conductances, we find that the intrinsic SHA in platinum has a much higher
value of 0.19 +- 0.04 as compared to the ST-SHA. The importance of the
interface transparency is further exemplified by the insertion of atomically
thin magnetic layers at the Pt/permalloy interface that we show strongly
modulates the magnitude of the ST-SHA.",1504.07929v1
2016-02-01,Facet-dependent giant spin orbit torque in single crystalline antiferromagnetic Ir-Mn / ferromagnetic permalloy bilayers,"There has been considerable interest in spin-orbit torques for the purpose of
manipulating the magnetization of ferromagnetic (FM) films or nano-elements for
spintronic technologies. Spin-orbit torques are derived from spin currents
created from charge currents in materials with significant spin-orbit coupling
that diffuse into an adjacent FM material. There have been intensive efforts to
search for candidate materials that exhibit large spin Hall angles, i.e.
efficient charge to spin current conversion. Here we report, using spin torque
ferromagnetic resonance, the observation of a giant spin Hall angle of up to
~0.35 in (100) oriented single crystalline antiferromagnetic (AF) IrMn3 thin
films, coupled to ferromagnetic permalloy layers, and a spin Hall angle that is
about three times smaller in (111) oriented films. For the (100) oriented
samples we show that the magnitude of the spin Hall angle can be significantly
changed by manipulating the populations of the various AF domains through field
annealing. Using ab-initio calculations we show that the triangular AF
structure of IrMn3 gives rise to a substantial intrinsic spin Hall conductivity
that is three times larger for the (100) than for the (111) orientations,
consistent with our experimental findings.",1602.00670v1
2017-11-20,Multi-spin-assisted optical pumping of bulk 13C nuclear spin polarization in diamond,"One of the most remarkable properties of the nitrogen-vacancy (NV) center in
diamond is that optical illumination initializes its electronic spin almost
completely, a feature that can be exploited to polarize other spin species in
their proximity. Here we use field-cycled nuclear magnetic resonance (NMR) to
investigate the mechanisms of spin polarization transfer from NVs to 13C spins
in diamond at room temperature. We focus on the dynamics near 51 mT, where a
fortuitous combination of energy matching conditions between electron and
nuclear spin levels gives rise to alternative polarization transfer channels.
By monitoring the 13C spin polarization as a function of the applied magnetic
field, we show 13C spin pumping takes place via a multi-spin cross relaxation
process involving the NV- spin and the electronic and nuclear spins of
neighboring P1 centers. Further, we find that this mechanism is insensitive to
the crystal orientation relative to the magnetic field, although the absolute
level of 13C polarization - reaching up to ~3% under optimal conditions - can
vary substantially depending on the interplay between optical pumping
efficiency, photo-generated carriers, and laser-induced heating.",1711.07576v1
2018-06-08,Transverse spin and transverse momentum in structured optical fields,"It has been recently recognized that in addition to the conventional
longitudinal angular momentum, structured (inhomogeneous) optical fields
exhibit helicity-independent transverse spin angular momentum (SAM) and an
unusual spin (circular polarization)- dependent transverse momentum, the
so-called Belinfante's spin momentum. Such highly nontrivial structure of the
momentum and the spin densities in the structured optical fields (e.g.,
evanescent fields) has led to a number of fundamentally interesting and
intricate phenomena, e.g., the quantum spin Hall effect of light and the
optical spin-momentum locking in surface optical modes similar to that observed
for electrons in topological insulators. In this review, we introduce the basic
concepts and look into the genesis of transverse SAM and transverse spin
momentum in structured light. We then discuss few illustrative examples of
micro and nano optical systems where these illusive entities can be observed.
The studied systems include planar and spherical micro and nano structures. We
also investigate the ways and means of enhancing the elusive extraordinary
spin. In particular, we show that dispersion management leading to avoided
crossing along with perfect absorption mediated by recently discovered coherent
perfect absorption can positively influence the resonant enhancement of the
transverse spin and spin momentum. The role of mode mixing and interference of
neighboring TE and TM scattering modes of diverse micro and nano optical
systems are illustrated with the selected examples. The results demonstrate
possibilities for the enhancement of not only the magnitudes but also the
spatial extent of transverse SAM and the transverse momentum components, which
opens up interesting avenues for experimental detection of these illusive
fundamental entities and may enhance the ensuing spin-based photonic
applications.",1806.03334v2
2018-02-09,Electron Spin Coherences in Rare-Earth Optically Excited States for Microwave to Optical Quantum Transducers,"Efficient and reversible optical to microwave coherent transducers are
required to enable entanglement transfer between superconducting qubits and
light for quantum networks. Rare-earth-doped crystals that possess narrow
optical and spin transitions are a promising way to implement these devices.
Current approaches use ground-state electron spin transitions that have
coherence lifetimes ($T_2$) often limited by spin flip-flop processes and/or
spectral diffusion, even at very low temperatures. Here, we investigate spin
coherence in an optically excited state of an Er$^{3+}$:Y$_2$SiO$_5$ crystal at
temperatures from 1.6 to 3.5 K and under a weak 8.7 mT magnetic field. Spin
coherence and population lifetimes of up to 1.6 $\mu$s and 1.2 ms,
respectively, are measured by 2- and 3-pulse optically-detected spin echo
experiments. Analysis of the dephasing processes suggest that ms $T_2$ can be
reached at lower temperatures for the excited-state spins, whereas ground-state
spin states could be limited to a few $\mu$s due to resonant interactions with
the other Er$^{3+}$ spins in the lattice (spin diffusion). We propose a quantum
transducer scheme with the potential for close to unit efficiency that exploits
the specific advantages offered by the spin states of optically excited
electronic energy levels.",1802.03354v2
2020-08-11,Impact of $\mathcal{T}$-symmetry on spin decoherence and control in a synthetic spin-orbit field,"The electrical control of a spin qubit in a quantum dot relies on spin-orbit
coupling (SOC), which could be either intrinsic to the underlying crystal
lattice or heterostructure, or extrinsic via, for example, a micro-magnet. Here
we show that a key difference between the intrinsic SOC and the synthetic SOC
introduced by a micro-magnet is their symmetry under time reversal.
Specifically, the time-reversal symmetry ($\mathcal{T}$-symmetry) of the
intrinsic SOC leads to not only the traditional van Vleck cancellation known
for spin relaxation, but also vanishing spin dephasing to the lowest order of
SOC, which we term as ""longitudinal spin-orbit field cancellation"". On the
other hand, the synthetic SOC from a micro-magnet breaks the
$\mathcal{T}$-symmetry, therefore eliminates both the ""van Vleck cancellation""
and the ""longitudinal spin-orbit field cancellation"". In other words, the
effective field $\vec\Omega$ experienced by the spin qubit does not depend on
the quantization magnetic field anymore, and a longitudinal component is
allowed for $\vec\Omega$ to the first order of SOC. Consequently, spin
relaxation and dephasing are qualitatively modified compared with the case of
the intrinsic SOC. Furthermore, the fidelity of electric-dipole spin resonance
based on $\vec\Omega$ could be optimized, with potential applications in
spin-based quantum computing.",2008.04671v2
2017-06-22,Observation of anomalous spin-torque generated by a ferromagnet,"In this work we report observation of in-plane current induced out-of-plane
magnetic field driven torque in spin valve structure. Since ferromagnet has
high spin orbit coupling it is expected to be the source of spin-orbit-torque
as it possesses anomalous-Hall-effect (AHE: equivalent to spin Hall effect in
heavy metal). So we have carried out spin-torque ferromagnetic resonance
(ST-FMR) experiment in a spin valve (consists of a fixed magnet and a free
magnet which are separated by Cu spacer), passing in-plane radio frequency
current and measuring DC voltage. Our experimental results eventually indicate
that spin torque exerted on the free magnet is not caused due to the spin
current injection by the fixed magnet owing to its AHE, but it is originated
from in-plane current driven out-of plane effective magnetic field. This is new
class of spin torque which is completely different from Slonczewski-spin
transfer torque and Rashba like field like torque. The effective out-of plane
magnetic field depends on the direction of current (in-plane) and magnetization
(in-plane) of the pinned layer. One possible mechanism behind this
unconventional torque could be intefacial spin-scattering which is also origin
of current in-plane GMR effect. Most importantly this effective out-of plane
torque can be useful to switch out-of plane magnetic bits in spintronic memory
application.",1706.07245v1
2022-07-06,Robust millisecond coherence times of erbium electron spins,"Erbium-doped solids are prime candidates for optical quantum communication
networks due to erbium's telecom C-band emission. A long-lived electron spin of
erbium with millisecond coherence time is highly desirable for establishing
entanglement between adjacent quantum repeater nodes while long-term storage of
the entanglement could rely on transferring to erbium's second-long coherence
nuclear spins. Here we report GHz-range electron spin transitions of
$^{167}\mathrm{Er}^{3+}$ in yttrium oxide ($\mathrm{Y_2O_3}$) matrix with
coherence times that are consistently longer than a millisecond. Instead of
addressing field-specific Zero First-Order Zeeman transitions, we probe weakly
mixed electron spins with the field orientation along the lower g-factors.
Using pulsed electron spin resonance spectroscopy, we find paramagnetic
impurities are the dominant source of decoherence, and by polarizing them we
achieve a Hahn echo spin $\mathrm{T_2}$ up to 1.46 ms, and a coherence time up
to 7.1 ms after dynamical decoupling. These coherence lifetimes are among the
longest found in crystalline hosts especially those with nuclear spins. We
further enhance the coherence time beyond conventional dynamical decoupling,
using customized sequences to simultaneously mitigate spectral diffusion and
Er-Er dipolar interactions. Despite nuclear and impurity spins in the host,
this work shows that long-lived erbium spins comparable to non-nuclear spin
hosts can be achieved. Our study not only establishes $^{167}\mathrm{Er}^{3+}$:
$\mathrm{Y_2 O_3}$ as a significantly promising quantum memory platform but
also provides a general guideline for engineering long-lived erbium spins in a
variety of host materials for quantum technologies.",2207.02708v1
2022-09-01,Spin-dependent metastable He ($2^3S$) atom scattering from ferromagnetic surfaces: Potential application to polarized-gas production,"A spin-polarized triplet metastable helium (He*) beam has been used as a
probe for surface magnetism, but changes in the spin state during scattering
from a surface remain unclear. In the present study, we explored this issue by
constructing an apparatus that allows us to direct a spin-polarized He* beam to
a surface and measure the spin polarization of He* scattered from the surface.
Magnetic hexapoles were used for both the beam polarization and the spin
analysis. The results of the spin-dependent He* scattering experiments on clean
Fe$_3$O$_4$(100), H-terminated Fe$_3$O$_4$(100), benzene-adsorbed
Fe$_3$O$_4$(100), and non-magnetic Cu(100) surfaces indicated that although the
spin direction of He* was mostly preserved during scattering from these
surfaces, spin-flop scattering of surviving He* occurred with a probability up
to approximately 0.1. Our results showed that the survival probability was
higher when the spins of He* and the Fe$_3$O$_4$(100) film were parallel, which
can be understood based on the lower He* resonance ionization rate for this
spin orientation. Based on our findings, we estimate that a non-polarized He*
gas becomes 10% spin-polarized after a single collision with a clean
Fe$_3$O$_4$(100) surface.",2209.00254v2
2023-09-07,Coherent spin dynamics between electron and nucleus within a single atom,"The nuclear spin, being much more isolated from the environment than its
electronic counterpart, enables quantum experiments with prolonged coherence
times and presents a gateway towards uncovering the intricate dynamics within
an atom. These qualities have been demonstrated in a variety of nuclear spin
qubit architectures, albeit with limited control over the direct environment of
the nuclei. As a contrasting approach, the combination of electron spin
resonance (ESR) and scanning tunnelling microscopy (STM) provides a bottom-up
platform to study the fundamental properties of nuclear spins of single atoms
on a surface. However, access to the time evolution of these nuclear spins, as
was recently demonstrated for electron spins, remained a challenge. Here, we
present an experiment resolving the nanosecond coherent dynamics of a
hyperfine-driven flip-flop interaction between the spin of an individual
nucleus and that of an orbiting electron. We use the unique local
controllability of the magnetic field emanating from the STM probe tip to bring
the electron and nuclear spins in tune, as evidenced by a set of avoided level
crossings in ESR-STM. Subsequently, we polarize both spins through scattering
of tunnelling electrons and measure the resulting free evolution of the coupled
spin system using a DC pump-probe scheme. The latter reveals a complex pattern
of multiple interfering coherent oscillations, providing unique insight into
the atom's hyperfine physics. The ability to trace the coherent hyperfine
dynamics with atomic-scale structural control adds a new dimension to the study
of on-surface spins, offering a pathway towards dynamic quantum simulation of
low-dimensional magnonics.",2309.03749v1
2024-02-06,Magnon mediated spin pumping by coupled ferrimagnetic garnets heterostructure,"Spin pumping has significant implications for spintronics, providing a
mechanism to manipulate and transport spins for information processing.
Understanding and harnessing spin currents through spin pumping is critical for
the development of efficient spintronic devices. The use of a magnetic
insulator with low damping, enhances the signal-to-noise ratio in crucial
experiments such as spin-torque ferromagnetic resonance (FMR) and spin pumping.
A magnetic insulator coupled with a heavy metal or quantum material offers a
more straight forward model system, especially when investigating spin-charge
interconversion processes to greater accuracy. This simplicity arises from the
absence of unwanted effects caused by conduction electrons unlike in
ferromagnetic metals. Here, we investigate the spin pumping in coupled
ferrimagnetic (FiM) Y3Fe5O12 (YIG)/Tm3Fe5O12 (TmIG) bilayers combined with
heavy-metal (Pt) using the inverse spin Hall effect (ISHE). It is observed that
magnon transmission occurs at both of the FiMs FMR positions. The enhancement
of spin pumping voltage (Vsp) in the FiM garnet heterostructures is attributed
to the strong interfacial exchange coupling between FiMs. The modulation of Vsp
is achieved by tuning the bilayer structure. Further, the spin mixing
conductance for these coupled systems is found to be 10^18 m^-2. Our findings
describe a novel coupled FiM system for the investigation of magnon coupling
providing new prospects for magnonic devices.",2402.03734v1
2024-02-22,Spin-dependent edge states in two-dimensional Dirac materials with a flat band,"The phenomenon of spin-dependent quantum scattering in two-dimensional (2D)
pseudospin-1/2 Dirac materials leading to a relativistic quantum chimera was
recently uncovered. We investigate spin-dependent Dirac electron optics in 2D
pseudospin-1 Dirac materials, where the energy-band structure consists of a
pair of Dirac cones and a flat band. In particular, with a suitable combination
of external electric fields and a magnetic exchange field, electrons with a
specific spin orientation (e.g., spin-down) can be trapped in a class of
long-lived edge modes, generating resonant scattering. The spin-dependent edge
states are a unique feature of flat-band Dirac materials and have no classical
correspondence. However, electrons with the opposite spin (i.e., spin up)
undergo conventional quantum scattering with a classical correspondence, which
can be understood in the framework of Dirac electron optics. A consequence is
that the spin-down electrons produce a large scattering probability with broad
scattering angle distribution in both near- and far-field regions, while the
spin-up electrons display the opposite behavior. Such characteristically
different behaviors of the electrons with opposite spins lead to spin
polarization that can be as high as nearly 100%.",2402.14248v1
2020-11-03,Controlling directed atomic motion and second-order tunneling of a spin-orbit-coupled atom in optical lattices,"We theoretically explore the tunneling dynamics for the tight-binding (TB)
model of a single spin-orbit-coupled atom trapped in an optical lattice
subjected to lattice shaking and to time-periodic Zeeman field. By means of
analytical and numerical methods, we demonstrate that the spin-orbit (SO)
coupling adds some new results to the tunneling dynamics in both multiphoton
resonance and far-off-resonance parameter regimes. When the driving frequency
is resonant with the static Zeeman field (multi-photon resonances), we obtain
an unexpected new dynamical localization (DL) phenomenon where the single
SO-coupled atom is restricted to making perfect two-site Rabi oscillation
accompanied by spin flipping.By using the unconventional DL phenomenon, we are
able to generate a ratchetlike effect which enables directed atomic motion
towards different directions and accompanies periodic spin-flipping under the
action of SO coupling. For the far-off-resonance case, we show that by
suppressing the usual inter-site tunneling alone, it is possible to realize a
type of spin-conserving second-order tunneling between next-nearest-neighboring
sites, which is not accessible in the conventional lattice system without SO
coupling. We also show that simultaneous controls of the usual inter-site
tunneling and the SO-coupling-related second-order-tunneling are necessary for
quasienergies flatness (collapse) and completely frozen dynamics to exist.
These results may be relevant to potential applications such as spin-based
quantum information processing and design of novel spintronics devices.",2011.01399v2
2001-01-26,Approach to the metal-insulator transition in La(1-x)CaxMnO3 (0<x<.2): magnetic inhomogeneity and spin wave anomaly,"We describe the evolution of the static and dynamic spin correlations of
La$_{1-x}$Ca$_x$MnO$_3$, for x=0.1, 0.125 and 0.2, where the system evolves
from the canted magnetic state towards the insulating ferromagnetic state,
approaching the metallic transition (x=0.22).
  In the x=0.1 sample, the observation of two spin wave branches typical of two
distinct types of magnetic coupling, and of a modulation in the elastic diffuse
scattering characteristic of ferromagnetic inhomogeneities, confirms the static
and dynamic inhomogeneous features previously observed at x$<$0.1. The
anisotropic q-dependence of the intensity of the low-energy spin wave suggests
a bidimensionnal character for the static inhomogeneities. At x=0.125, which
corresponds to the occurence of a ferromagnetic and insulating state, the two
spin wave branches reduce to a single one, but anisotropic. At this
concentration, an anomaly appears at {\bf q$_0$}=(1.25,1.25,0), that could be
related to an underlying periodicity, as arising from (1.5,1.5,0)
superstructures.
  At x=0.2, the spin-wave branch is isotropic. In addition to the anomaly
observed at q$_0$, extra magnetic excitations are observed at larger q, forming
an optical branch. The two dispersion curves suggest an anti-crossing behavior
at some {\bf q$_0$'} value, which could be explained by a folding due to an
underlying perodicity involving four cubic lattice spacings.",0101414v1
2017-08-29,Spin wave damping arising from phase coexistence below $T_c$ in colossal magnetoresistive La$_{0.7}$Ca$_{0.3}$MnO$_3$,"While the spin dynamics of La$_{0.7}$Ca$_{0.3}$MnO$_3$ in the ferromagnetic
phase are known to be unconventional, previous measurements have yielded
contradictory results regarding the damping of spin wave excitations. Neutron
spectroscopy measurements on a sample with a transition temperature of
$T_c$=257 K, higher than most single crystals, unambiguously reveal an
anomalous increase in spin wave damping for excitations approaching the
Brillouin zone boundary along the [$100$] direction that cannot be explained as
an artifact due to a noninteracting phonon branch. Spin waves throughout the
($HK0$) plane display a common trend where the spin wave damping is dependent
upon the excitation energy, increasing for energies above roughly 15 meV and
reaching a full width at half maximum of at least 20 meV. The results are
consistent with a model of intrinsic spatial inhomogeneity with phase separated
regions approximately 18 {\AA} in size persisting over a large range of
temperatures below $T_c$.",1708.08960v2
2018-08-01,Raman fingerprint of two terahertz spin wave branches in a two-dimensional honeycomb Ising ferromagnet,"Two-dimensional (2D) magnetism has been long sought-after and only very
recently realized in atomic crystals of magnetic van der Waals materials. So
far, a comprehensive understanding of the magnetic excitations in such 2D
magnets remains missing. Here we report polarized micro-Raman spectroscopy
studies on a 2D honeycomb ferromagnet CrI3. We show the definitive evidence of
two sets of zero-momentum spin waves at frequencies of 2.28 terahertz (THz) and
3.75 THz, respectively, that are three orders of magnitude higher than those of
conventional ferromagnets. By tracking the thickness dependence of both spin
waves, we reveal that both are surface spin waves with lifetimes an order of
magnitude longer than their temporal periods. Our results of two branches of
high-frequency, long-lived surface spin waves in 2D CrI3 demonstrate intriguing
spin dynamics and intricate interplay with fluctuations in the 2D limit, thus
opening up opportunities for ultrafast spintronics incorporating 2D magnets.",1808.00168v3
2019-02-27,Anomalous phase ordering of a quenched ferromagnetic superfluid,"Coarsening dynamics, the canonical theory of phase ordering following a
quench across a symmetry breaking phase transition, is thought to be driven by
the annihilation of topological defects. Here we show that this understanding
is incomplete. We simulate the dynamics of an isolated spin-1 condensate
quenched into the easy-plane ferromagnetic phase and find that the mutual
annihilation of spin vortices does not take the system to the equilibrium
state. A nonequilibrium background of long wavelength spin waves remain at the
Berezinskii-Kosterlitz-Thouless temperature, an order of magnitude hotter than
the equilibrium temperature. The coarsening continues through a second much
slower scale invariant process with a length scale that grows with time as
$t^{1/3}$. This second regime of coarsening is associated with spin wave energy
transport from low to high wavevectors, bringing about the the eventual
equilibrium state. Because the relevant spin waves are noninteracting, the
transport occurs through a dynamic coupling to other degrees of freedom of the
system. The transport displays features of a spin wave energy cascade,
providing a potential profitable connection with the emerging field of spin
wave turbulence. Strongly coupling the system to a reservoir destroys the
second regime of coarsening, allowing the system to thermalise following the
annihilation of vortices.",1902.10792v4
2021-08-23,High-accuracy simulations of highly spinning binary neutron star systems,"With an increasing number of expected gravitational-wave detections of binary
neutron star mergers, it is essential that gravitational-wave models employed
for the analysis of observational data are able to describe generic compact
binary systems. This includes systems in which the individual neutron stars are
millisecond pulsars for which spin effects become essential. In this work, we
perform numerical-relativity simulations of binary neutron stars with aligned
and anti-aligned spins within a range of dimensionless spins of $\chi \sim
[-0.28,0.58]$. The simulations are performed with multiple resolutions, show a
clear convergence order and, consequently, can be used to test existing
waveform approximants. We find that for very high spins gravitational-wave
models that have been employed for the interpretation of GW170817 and GW190425
are not capable of describing our numerical-relativity dataset. We verify
through a full parameter estimation study in which clear biases in the estimate
of the tidal deformability and effective spin are present. We hope that in
preparation of the next gravitational-wave observing run of the Advanced LIGO
and Advanced Virgo detectors our new set of numerical-relativity data can be
used to support future developments of new gravitational-wave models.",2108.10429v1
2019-10-04,Spin-wave directional anisotropies in antiferromagnetic Ba$_{3}$NbFe$_{3}$Si$_{2}$O$_{14}$,"Ba$_{3}$NbFe$_{3}$Si$_{2}$O$_{14}$ (langasite) is structurally and
magnetically single domain chiral with the magnetic helicity induced through
competing symmetric exchange interactions. Using neutron scattering, we show
that the spin-waves in antiferromagnetic langasite display directional
anisotropy. On applying a time reversal symmetry breaking magnetic field along
the $c$-axis, the spin wave energies differ when the sign is reversed for
either the momentum transfer $\pm$ $\vec{Q}$ or applied magnetic field $\pm$
$\mu_{0}$H. When the field is applied within the crystallographic $ab$-plane,
the spin wave dispersion is directionally \textit{isotropic} and symmetric in
$\pm$ $\mu_{0}$H. However, a directional anisotropy is observed in the spin
wave intensity. We discuss this directional anisotropy in the dispersion in
langasite in terms of a field induced precession of the dynamic unit cell
staggered magnetization. Directional anisotropy, or often referred to as non
reciprocal responses, can occur in antiferromagnetic phases in the absence of
the Dzyaloshinskii-Moriya interaction or other effects resulting from
spin-orbit coupling.",1910.01977v2
2020-01-31,Temperature dependence of spin pinning and spin-wave dispersion in nanoscopic ferromagnetic waveguides,"The field of magnonics attracts significant attention due to the possibility
of utilizing information coded into the spin-wave phase or amplitude to perform
computation operations on the nanoscale. Recently, spin waves were investigated
in Yttrium Iron Garnet (YIG) waveguides with widths ranging down to 50 nm and
aspect ratios thickness over width approaching unity. A critical width was
found, below which the exchange interaction suppresses the dipolar pinning
phenomenon and the system becomes unpinned. Here we continue these
investigations and analyse the pinning phenomenon and spin-wave dispersions as
a function of temperature, thickness and material of choice. Higher order
modes, the influence of a finite wavevector along the waveguide and the impact
of the pinning phenomenon on the spin-wave lifetime are discussed as well as
the influence of a trapezoidal cross section and edge roughness of the
waveguides. The presented results are of particular interest for potential
applications in magnonic devices and the incipient field of quantum magnonics
at cryogenic temperatures.",2002.00003v1
2021-09-30,Selection rules and dynamic magnetoelectric effect of the spin waves in multiferroic BiFeO$_3$,"We report the magnetic field dependence of the THz absorption and
non-reciprocal directional dichroism spectra of BiFeO$_3$ measured on the three
principal crystal cuts for fields applied along the three principal directions
of each cut. From the systematic study of the light polarization dependence we
deduced the optical selection rules of the spin-wave excitations. Our THz data,
combined with small-angle neutron scattering results showed that i) an in-plane
magnetic field rotates the $\mathbf{q}$ vectors of the cycloids perpendicular
to the magnetic field, and ii) the selection rules are mostly determined by the
orientation of the $\mathbf{q}$ vector with respect to the electromagnetic
fields. We observed a magnetic field history dependent change in the strength
and the frequency of the spin-wave modes, which we attributed to the change of
the orientation and the length of the cycloidal $\mathbf{q}$ vector,
respectively. Finally, we compared our experimental data with the results of
linear spin-wave theory that reproduces the magnetic field dependence of the
spin-wave frequencies and most of the selection rules, from which we identified
the spin-polarization coupling terms relevant for the optical magnetoelectric
effect.",2109.14990v1
2022-09-29,Spin Dynamics in Patterned Magnetic Multilayers with Perpendicular Magnetic Anisotropy,"The magnetization dynamics in nanostructures has been extensively studied in
the last decades, and nanomagnetism has evolved significantly over that time,
discovering new effects, developing numerous applications, and identifying
promising new directions. This includes magnonics, an emerging research field
oriented on the study of spin-wave dynamics and their applications. In this
context, thin ferromagnetic films with perpendicular magnetic anisotropy (PMA)
offer interesting opportunities to study spin waves, in particular, due to
out-of-plane magnetization in remanence or at relatively weak external magnetic
fields. This is the only magnetization configuration offering isotropic
in-plane spin-wave propagation within the sample plane, the forward volume
magnetostatic spin-wave geometry. The isotropic dispersion relation is highly
important in designing signal-processing devices, offering superior prospects
for direct replicating various concepts from photonics into magnonics.
Analogous to photonic or phononic crystals, which are the building blocks of
optoelectronics and phononics, magnonic crystals are considered as key
components in magnonics applications. Arrays of nanodots and structured
ferromagnetic thin films with a periodic array of holes, popularly known as
antidot lattices based on PMA multilayers have been recently studied. Novel
magnonic properties related to propagating spin-wave modes, exploitation of the
band gaps, and confined modes, were demonstrated. Also, the existence of
nontrivial magnonic band topologies has been shown. Moreover, the combination
of PMA and Dzyaloshinskii-Moriya interaction leads to the formation of chiral
magnetization states, including N\'eel domain walls, skyrmions, and skyrmionium
states.",2209.14824v2
2022-11-03,Spin-orbit and exchange proximity couplings in graphene/1T-TaS$_2$ heterostructure triggered by a charge density wave,"Proximity-induced fine features and spin-textures of the electronic bands in
graphene-based van der Waals heterostructures can be explored from the point of
tailoring a twist angle. Here we study spin-orbit coupling and exchange
coupling engineering of graphene states in the proximity of 1T-TaS$_2$ not
triggering the twist, but a charge density wave in 1T-TaS$_2$-a realistic
low-temperature phase. Using density functional theory and effective model we
found that the emergence of the charge density wave in 1T-TaS$_2$ significantly
enhances Rashba spin-orbit splitting in graphene and tilts the spin texture by
a significant Rashba angle-in a very similar way as in the conventional
twist-angle scenarios. Moreover, the partially filled Ta $d$-band in the charge
density wave phase leads to the spontaneous emergence of the in-plane magnetic
order that transgresses via proximity from 1T-TaS$_2$ to graphene, hence,
simultaneously superimposing along the spin-orbit also the exchange coupling
proximity effect. To describe this intricate proximity landscape we have
developed an effective model Hamiltonian and provided a minimal set of
parameters that excellently reproduces all the spectral features predicted by
the first-principles calculations. Conceptually, the charge density wave
provides a highly interesting knob to control the fine features of electronic
states and to tailor the superimposed proximity effects-a sort of twistronics
without twist.",2211.02153v2
2023-01-30,Transverse spin angular momentum of space-time surface plasmon polariton wave packet,"In addition to longitudinal spin angular momentum (SAM) along the axis of
propagation of light, spatially structured electromagnetic fields such as
evanescent waves and focused beams have recently been found to possess
transverse SAM in the direction perpendicular to the axis of propagation. In
particular, the SAM of SPPs with spatial structure has been extensively studied
in the last decade after it became clear that evanescent fields with spatially
structured energy flow generate threedimensional spin texture. Here we present
numerical calculations of the space-time surface plasmon polariton (ST-SPP)
wave packet, a plasmonic bullet that propagates at an arbitrary group velocity
while maintaining its spatial distribution. ST-SPP wave packets with complex
spatial structure and energy flow density distribution determined by the group
velocity are found to propagate with accompanying three-dimensional spin
texture and finite topological charge density. Furthermore, the spatial
distribution of the spin texture and topological charge density determined by
the spatial structure of the SPP is controllable, and the deformation
associated with propagation is negligible. ST-SPP wave packets, which can
stably transport customizable three-dimensional spin textures and topological
charge densities, can be excellent subjects of observation in studies of
spinphotonics and optical topological materials.",2301.12654v2
2023-07-18,Proton 0.01 MeV resonance width and low-energy $S$-factor of p+10B fusion,"{\bf{Purpose}:} In this paper, the proton resonance width of the
near-threshold resonance is calculated using two different approaches. The
values of the proton width are used to calculate the low-energy $S$-factor. \\
{\bf{Method:}} First, the proton resonance width is estimated using the mirror
symmetry of the resonance $ {}^{11}{\rm C}(E_{x}=8.70\, {\rm
MeV};\,\frac{5}{2}^{+})$ and the mirror bound state ${}^{11}{\rm
B}(E_{x}=9.272\, {\rm MeV};\,\frac{5}{2}^{+})$. In the second approach, this
width is estimated using the $R$-matrix definition of the observable resonance
width, which is expressed in terms of the $p-{}^{10}{\rm B}$ resonant wave
function calculated in the potential approach and the spectroscopic factor. \\
{\bf{Results}:} Depending on the method chosen, the calculated proton resonance
width varies from $\,1.03 \times 10^{-19}\,$MeV to $\,2.96 \times
10^{-19}\,$MeV. The role of the near-threshold resonance is determined using
fitting of two low-energy $S$-factors from direct measurements [C. Angulo {\it
et al.}, Z. Phys. A {\bf 345}, 333 (1993)] and from the indirect Trojan horse
method (THM) [ A. Cvetinovi\'c {\it et al.}, Phys. Rev. C {\bf 97}, 065801
(2018)]. Within the framework of the $R$-matrix method using the determined
proton resonance widths and the modified THM parameters for six low-lying
resonances, the low-energy $S$-factors were calculated and compared with the
corresponding experimental $S$-factors. The closest agreement with the data is
achieved with the proton resonance widths $1.0 \times 10^{-19}$ MeV when
fitting the $S$-factor from the THM indirect measurements, and $\,1.68 \times
10^{-19}\,$ MeV and $\,2.5 \times 10^{-19}\,$ MeV when fitting the $S$-factor
from [Angulo {\it et al}, Z. Phys. A {\bf 345}, 333 (1993)].\",2307.08963v2
2005-12-14,Quantum theory for electron spin decoherence induced by nuclear spin dynamics in semiconductor quantum computer architectures: Spectral diffusion of localized electron spins in the nuclear solid-state environment,"We consider the decoherence of a single localized electron spin due to its
coupling to the lattice nuclear spin bath in a semiconductor quantum computer
architecture. In the presence of an external magnetic field and at low
temperatures, the dominant decoherence mechanism is the spectral diffusion of
the electron spin resonance frequency due to the temporally fluctuating random
magnetic field associated with the dipolar interaction induced flip-flops of
nuclear spin pairs. The electron spin dephasing due to this random magnetic
field depends intricately on the quantum dynamics of the nuclear spin bath,
making the coupled decoherence problem difficult to solve. We provide a
formally exact solution of this non-Markovian quantum decoherence problem which
numerically calculates accurate spin decoherence at short times, which is of
particular relevance in solid-state spin quantum computer architectures. A
quantum cluster expansion method is developed, motivated, and tested for the
problem of localized electron spin decoherence due to dipolar fluctuations of
lattice nuclear spins. The method is presented with enough generality for
possible application to other types of spin decoherence problems. We present
numerical results which are in quantitative agreement with electron spin echo
measurements in phosphorus doped silicon. We also present spin echo decay
results for quantum dots in GaAs which differ qualitatively from that of the
phosphorus doped silicon system. Our theoretical results provide the ultimate
limit on the spin coherence (at least, as characterized by Hahn spin echo
measurements) of localized electrons in semiconductors in the low temperature
and the moderate to high magnetic field regime of interest in scalable
semiconductor quantum computer architectures.",0512323v3
2016-02-25,Electronic Spin Transport in Dual-Gated Bilayer Graphene,"The elimination of extrinsic sources of spin relaxation is key in realizing
the exceptional intrinsic spin transport performance of graphene. Towards this,
we study charge and spin transport in bilayer graphene-based spin valve devices
fabricated in a new device architecture which allows us to make a comparative
study by separately investigating the roles of substrate and polymer residues
on spin relaxation. First, the comparison between spin valves fabricated on
SiO2 and BN substrates suggests that substrate-related charged impurities,
phonons and roughness do not limit the spin transport in current devices. Next,
the observation of a 5-fold enhancement in spin relaxation time in the
encapsulated device highlights the significance of polymer residues on spin
relaxation. We observe a spin relaxation length of ~ 10 um in the encapsulated
bilayer with a charge mobility of 24000 cm2/Vs. The carrier density dependence
of spin relaxation time has two distinct regimes; n<4 x 1012 cm-2, where spin
relaxation time decreases monotonically as carrier concentration increases, and
n>4 x 1012 cm-2, where spin relaxation time exhibits a sudden increase. The
sudden increase in the spin relaxation time with no corresponding signature in
the charge transport suggests the presence of a magnetic resonance close to the
charge neutrality point. We also demonstrate, for the first time, spin
transport across bipolar p-n junctions in our dual-gated device architecture
that fully integrates a sequence of encapsulated regions in its design. At low
temperatures, strong suppression of the spin signal was observed while a
transport gap was induced, which is interpreted as a novel manifestation of
impedance mismatch within the spin channel.",1602.07817v2
2001-11-15,Temperature Isotropization in Solar Flare Plasmas due to the Electron Firehose Instability,"The isotropization process of a collisionless plasma with an electron
temperature anisotropy along an external magnetic field ($T_\| ^e\gg
T_\perp^e$, $\|$ and $\perp$ with respect to the background magnetic field) and
isotropic protons is investigated using a particle-in-cell(PIC) code.
Restricting wave growth mainly parallel to the external magnetic field, the
isotropization mechanism is identified to be the Electron Firehose Instability
(EFI). The free energy in the electrons is first transformed into left-hand
circularly polarized transverse low-frequency waves by a non-resonant
interaction. Fast electrons can then be scattered towards higher perpendicular
velocities by gyroresonance, leading finally to a complete isotropization of
the velocity distribution. During this phase of the instability, Langmuir waves
are generated which may lead to the emission of radio waves. A large fraction
of the protons is resonant with the left-hand polarized electromagnetic waves,
creating a proton temperature anisotropy $T_\|^p < T_\perp^p$. The parameters
of the simulated plasma are chosen compatible to solar flare conditions. The
results indicate the significance of this mechanism in the particle
acceleration context: The EFI limits the anisotropy of the electron velocity
distribution, and thus provides the necessary condition for further
acceleration. It enhances the pitch-angle of the electrons and heats the ions.",0111303v1
2002-05-06,New mechanism of pulsar radio emission,"It is shown that pulsar radio emission can be generated effectively through a
streaming motion in the polar-cap regions of a pulsar magnetosphere causing
nonresonant growth of waves that can escape directly. As in other beam models,
a relatively low-energy high-density beam is required. The instability
generates quasi-transverse waves in a beam mode at frequencies that can be well
below the resonant frequency. As the waves propagate outward growth continues
until the height at which the wave frequency is equal to the resonant
frequency. Beyond this point the waves escape in a natural plasma mode (L-O
mode). This one-step mechanism is much more efficient than previously widely
considered multi-step mechanisms.",0205069v1
2005-04-21,Effect of spatial-time dispersion on the propagation of electromagnetic waves in photonic crystals,"We study the influence of the space and time dispersion on the frequency
dependence of the wave vectors of electromagnetic waves propagating in
three-dimensional photonic crystals. Two types of structures are considered:
media with weak periodic modulation of the permittivity, and photonic crystals
composed of the periodically arranged identical resonant dielectric particles.
It is shown that in these systems, in contrast to electrons in solid crystals,
different types of excitations exist. For example, a peculiar kind of
polaritons arises in the photonic crystals due to the interaction of the
electromagnetic field, eigenoscillations of the dielectric medium, and Debye
resonance. The widths of the transparency zones and of the band gaps have been
calculated as functions of the frequency and of the parameters of the media. It
is shown that in the photonic crystals with dispersion, the number of
transparency bands is larger than in non-dispersive systems, and the width of
the gaps in the frequency spectrum of photons depends on the wave vector. The
interaction of different types of waves deforms the Brillouin zone, so that it
may not have a plane boundary (for example, a sphere), in which case the
classical Bragg condition does not hold.",0504556v2
2005-06-14,Dressed state approach to matter wave mixing of bosons,"A dressed state approach to mixing of bosonic matter waves is presented. Two
cases are studied using this formalism. In the first, two macroscopically
populated modes of atoms (two-wave mixing) are coupled through the presence of
light. In the second case, three modes of Bogoliubov quasiparticles (three-wave
mixing) are coupled through s-wave interaction. In both cases wave mixing
induces oscillations in the population of the different modes that decay due to
interactions. Analytic expressions for the dressed basis spectrum and the
evolution of the mode populations in time are derived both for resonant mixing
and non-resonant mixing. Oscillations in the population of a given mode are
shown to lead to a splitting in the decay spectrum of that mode, in analogy to
the optical Autler-Townes splitting in the decay spectrum of a strongly driven
atom. These effects cannot be described by a mean-field approximation.",0506318v1
2007-01-29,Local density of states and Friedel oscillations around a non-magnetic impurity in unconventional density wave,"We present a mean-field theoretical study on the effect of a single
non-magnetic impurity in quasi-one dimensional unconventional density wave. The
local scattering potential is treated within the self-consistent $T$-matrix
approximation. The local density of states around the impurity shows the
presence of resonant states in the vicinity of the Fermi level, much the same
way as in $d$-density waves or unconventional superconductors. The assumption
for different forward and backscattering, characteristic to quasi-one
dimensional systems in general, leads to a resonance state that is double
peaked in the pseudogap. The Friedel oscillations around the impurity are also
explored in great detail, both within and beyond the density wave coherence
length $\xi_0$. Beyond $\xi_0$ we find power law behavior as opposed to the
exponential decay of conventional density wave. The entropy and specific heat
contribution of the impurity are also calculated for arbitrary scattering
strengths.",0701732v1
1995-12-27,Integral Transform Technique for Meson Wave Functions,"In a recent paper [1] we have proposed a new approach for extracting the wave
function of the $\pi$-meson $\varphi_{\pi}(x)$ and the masses and
  wave functions of its first resonances from the new QCD sum rules for
non-diagonal correlators obtained in [2]. Here, we test our approach using an
exactly solvable toy model as an illustrating example. We demonstrate the
validity of the method and suggest a pure algebraic procedure for extracting
the masses and wave functions relating to the case under investigation. We also
explore the stability of the procedure under perturbations of the theoretical
part of the sum rule. In application to the pion case, this results not only in
the mass and wave function of the first resonance ($\pi'$), but also in the
estimation of $\pi''$-mass.",9512432v2
2003-10-05,Non-steady-state extremely asymmetrical scattering of waves in periodic gratings,"Extremely asymmetrical scattering (EAS) is a highly resonant type of Bragg
scattering with a strong resonant increase of the scattered wave amplitude
inside and outside the grating. EAS is realized when the scattered wave
propagates parallel to the grating boundaries. We present a rigorous algorithm
for the analysis of non-steady-state EAS, and investigate the relaxation of the
incident and scattered wave amplitudes to their steady-state values.
Non-steady-state EAS of bulk TE electromagnetic waves is analyzed in narrow and
wide, slanted, holographic gratings. Typical relaxation times are determined
and compared with previous rough estimations. Physical explanation of the
predicted effects is presented.",0310023v1
2006-07-31,Dynamic radiation force of acoustic waves on solid elastic spheres,"The present study concerns the dynamic radiation force on solid elastic
spheres exerted by a plane wave with two frequencies (bichromatic wave)
considering the nonlinearity of the fluid. Our approach is based on solving the
wave scattering for the sphere in the quasilinear approximation within the
preshock wave range. The dynamic radiation force is then obtained by
integrating the component of the momentum flux tensor at the difference of the
primary frequencies over the boundary of the sphere. Results reveal that
effects of the nonlinearity of the fluid plays a major role in dynamic
radiation force leading it to a parametric amplification regime. The developed
theory is used to calculate the dynamic radiation force on three different
solid spheres (aluminium, silver, and tungsten). Resonances are observed in the
spectrum of the force on the spheres. They have larger amplitude and better
shape than resonances present in static radiation force.",0607295v1
2003-01-30,Dynamic effects of electromagnetic wave on a damped two-level atom,"We studied the dynamic effects of an electromagnetic(EM) wave with circular
polarization on a two-level damped atom. The results demonstrate interesting ac
Stark split of energy levels of damped atom. The split levels have different
energies and lifetimes, both of which depend on the interaction and the damping
rate of atom. When the frequency of the EM wave is tuned to satisfy the
resonance condition in the strong coupling limit, the transition probability
exhibits Rabi oscillation. Momentum transfer between atom and EM wave shows
similar properties as the transition probability under resonance condition. For
a damped atom interacting with EM field, there exists no longer stable state.
More importantly, if the angular frequency of the EM wave is tuned the same as
the atomic transition frequency and its amplitude is adjusted appropriately
according to the damping coefficients, we can prepare a particular 'Dressed
State' of the coupled system between atom and EM field and can keep the system
coherently in this 'Dressed state' for a very long time. This opens another way
to prepare coherent atomic states.",0301166v1
2008-01-09,A Diffractive Study of Parametric Process in Nonlinear Photonic Crystals,"We report a general description of quasi-phase-matched parametric process in
nonlinear photonic crystals (NLPC) by extending the conventional X-ray
diffraction theory in solids. Under the virtual wave approximation,
phase-matching resonance is equivalent to the diffraction of the scattered
virtual wave. Hence a modified NLPC Ewald construction can be built up, which
illustrates the nature of the accident for the diffraction of the virtual wave
in NLPC and further reveals the complete set of diffractions of the virtual
wave for both of the air-dielectric and dielectric-dielectric contacts. We show
the two basic linear sequences, the anti-stacking and para-stacking linear
sequences, in one-dimension (1D) NLPC and present a general rule for multiple
phase-matching resonances in 1D NLPC. The parameters affecting the NLPC
structure factor are investigated, which indicate that not only the Ewald
construction but also the relative NLPC atom size together determine whether a
diffraction of the virtual wave can occur in 2D NLPC. The results also show
that 1D NLPC is a better choice than 2D NLPC for a single parametric process.",0801.1456v1
2008-09-05,Matter-wave cavity gravimeter,"We propose a gravimeter based on a matter-wave resonant cavity loaded with a
Bose-Einstein condensate and closed with a sequence of periodic Raman pulses.
The gravimeter sensitivity increases quickly with the number of cycles
experienced by the condensate inside the cavity. The matter wave is refocused
thanks to a spherical wave-front of the Raman pulses. This provides a
transverse confinement of the condensate which is discussed in terms of a
stability analysis. We develop the analogy of this device with a resonator in
momentum space for matter waves.",0809.1054v2
2010-07-07,Observational evidence of resonantly damped propagating kink waves in the solar corona,"In this Letter we establish clear evidence for the resonant absorption
damping mechanism by analyzing observational data from the novel Coronal
Multi-Channel Polarimeter (CoMP). This instrument has established that in the
solar corona there are ubiquitous propagating low amplitude ($\approx$1 km
s$^{-1}$) Alfv\'{e}nic waves with a wide range of frequencies. Realistically
interpreting these waves as the kink mode from magnetohydrodynamic (MHD) wave
theory, they should exhibit a frequency dependent damping length due to
resonant absorption, governed by the TGV relation showing that transversal
plasma inhomogeneity in coronal magnetic flux tubes causes them to act as
natural low-pass filters. It is found that observed frequency dependence on
damping length (up to about 8 mHz) can be explained by the kink wave
interpretation and furthermore, the spatially averaged equilibrium parameter
describing the length scale of transverse plasma density inhomogeneity over a
system of coronal loops is consistent with the range of values estimated from
TRACE observations of standing kink modes.",1007.1080v1
2011-02-03,High speed imaging of traveling waves in a granular material during silo discharge,"We report experimental observations of sound waves in a granular material
during resonant silo discharge called silo music. The grain motion was tracked
by high speed imaging while the resonance of the silo was detected by
accelerometers and acoustic methods. The grains do not oscillate in phase at
neighboring vertical locations, but information propagates upward in this
system in the form of sound waves. We show that the wave velocity is not
constant throughout the silo, but considerably increases towards the lower end
of the system, suggesting increased pressure in this region, where the flow
changes from cylindrical to converging flow. In the upper part of the silo the
wave velocity matches the sound velocity measured in the same material when
standing (in the absence of flow). Grain oscillations show a stick-slip
character only in the upper part of the silo.",1102.0724v1
2011-12-17,Experimental evidence of a triadic resonance of plane inertial waves in a rotating fluid,"Plane inertial waves are generated using a wavemaker, made of oscillating
stacked plates, in a rotating water tank. Using particle image velocimetry, we
observe that, after a transient, the primary plane wave is subject to a
subharmonic instability and excites two secondary plane waves. The measured
frequencies and wavevectors of these secondary waves are in quantitative
agreement with the predictions of the triadic resonance mechanism. The
secondary wavevectors are found systematically more normal to the rotation axis
than the primary wavevector: this feature illustrates the basic mechanism at
the origin of the energy transfers towards slow, quasi two-dimensional, motions
in rotating turbulence.",1112.4053v1
2012-02-02,Mechanism of destruction of transport barriers in geophysical jets with Rossby waves,"The mechanism of destruction of a central transport barrier in a dynamical
model of a geophysical zonal jet current in the ocean or the atmosphere with
two propagating Rossby waves is studied. We develop a method for computing a
central invariant curve which is an indicator of existence of the barrier.
Breakdown of this curve under a variation of the Rossby wave amplitudes and
onset of chaotic cross-jet transport happen due to specific resonances
producing stochastic layers in the central jet. The main result is that there
are resonances breaking the transport barrier at unexpectedly small values of
the amplitudes that may have serious impact on mixing and transport in the
ocean and the atmosphere. The effect can be found in laboratory experiments
with azimuthal jets and Rossby waves in rotating tanks under specific values of
the wave numbers that are predicted in the theory.",1202.0352v1
2014-09-27,Modulation instability in nonlinear positive-negative index waveguide array,"Modulation instability in a nonlinear optical waveguide array with
alternating positive and negative refractive indices is investigated
analytically. Particular solutions of a system of coupled nonlinear equations
are found. These solutions describe propagation of the continuum backward and
forward waves in longitudinal direction of considered system. Instability of
these waves is investigated with a linear stability analysis. A gain spectrum
depending on different parameters of considered system: electromagnetic field
power and ratio of the backward to forward wave amplitude, is studied
analytically and numerically. It was shown that in case of Bragg resonance the
continuum waves are stable. If nonlinearity assists at one kind of waveguides
only and another one is linear one then the modulation instability does not
occur. Out of Bragg resonance in defocusing waveguides the instability of the
continuum waves is reduced.",1409.7846v1
2015-01-10,Subwavelength edge detection through trapped resonances in waveguides,"Lenses that can collect the perfect image of an object must restore
propagative and evanescent waves. However, for efficient information transfer,
e.g., in compressed sensing, it is often desirable to detect only the fast
spatial variations of the wave field (carried by evanescent waves), as the one
created by edges or small details. Image processing edge detection algorithms
perform such operation but they add time and complexity to the imaging process.
Here, we present a new subwavelength approach that generates an image of only
those components of the acoustic field that are equal to or smaller than the
operating wavelength. The proposed technique converts evanescent waves into
propagative waves exciting trapped resonances in a waveguide, and it uses
periodicity to attenuate the propagative components. This approach achieves
resolutions about an order of magnitude smaller than the operating wavelength
and makes it possible to visualize independently edges aligned along different
directions.",1501.02406v1
2015-08-27,The Effect of Vertical Temperature Gradient on the Propagation of Three-dimensional Waves in a Protoplanetary Disk,"Excitation and propagation of waves in a thermally stratified disk with an
arbitrary vertical temperature profile are studied. Previous analytical studies
of three-dimensional waves had been focused on either isothermal or polytropic
vertical disk structures. However, at the location in a protoplanetary disk
where the dominant heating source is stellar irradiation, the temperature
gradient may become positive in the vertical direction. We extend the analysis
to study the effects of the vertical temperature structure on the waves that
are excited at the Lindblad resonances. For a hotter disk atmosphere, the
$f$-mode contributes less to the torque and remains confined near the midplane
as it propagates away from the resonances. On the other hand, the excitation of
the $g$-modes is stronger. As they propagate, they channel to the top of disk
atmosphere and their group velocities decrease. The differences compared to
previous studies may have implications in understanding the wave dynamics in a
realistic disk structure.",1508.06833v1
2015-12-03,Dynamics of solitons in multicomponent long wave-short wave resonance interaction system,"In this paper, we study the formation of solitons, their propagation and
collision behaviour in an integrable multicomponent (2+1)-dimensional long
wave-short wave resonance interaction ($M$-LSRI) system. First, we briefly
revisit our earlier results on the dynamics of bright solitons and demonstrate
the fascinating energy exchange collision of bright solitons appearing in the
short-wave components of the $M$-LSRI system. Then, we explicitly construct the
exact one- and two- multicomponent dark soliton solutions of the $M$-LSRI
system by using the Hirota's direct method and explore its propagation
dynamics. Also, we study the features of dark soliton collisions.",1512.01034v1
2016-02-19,Broadband wide-angle absorption enhancement due to mode conversion in cold unmagnetized plasmas with periodic density variations,"We study theoretically the mode conversion and the associated resonant
absorption of p-polarized electromagnetic waves into longitudinal plasma
oscillations in cold, unmagnetized and stratified plasmas with periodic spatial
density variations. We consider sinusoidal density configurations for which the
frequency band where mode conversion occurs is well included within a
transmission band of the one-dimensional plasma photonic crystal. We calculate
the mode conversion coefficient, which measures the fraction of the
electromagnetic wave energy absorbed into the plasma, and the spatial
distribution of the magnetic field intensity for various values of the wave
frequency and the incident angle using the invariant imbedding theory of mode
conversion. We find that the absorption is greatly enhanced over a wide range
of frequency and incident angle due to the interplay between the mode
conversion and the photonic band structure. The enhancement occurs because for
frequencies within a transmission band, the wave reflection is strongly
suppressed and the waves penetrate more deeply into the inhomogeneous region,
thereby increasing the possibility for them to reach many resonance points
where the dielectric permittivity vanishes.",1602.06020v1
2016-08-18,Vector soliton of the Love wave in ZnO/LiNbO_{3} structure,"A theory of an acoustic vector soliton of the Love wave is constructed. The
nonlinear Love wave propagating along the interface between of a plane surface
layer and the elastic semi-space under the condition of acoustic self-induced
transparency is investigated. A thin resonance transition layer containing
paramagnetic impurity atoms or semiconductor quantum dots sandwiched between
these two connected media. Explicit analytical expressions for the profile and
parameters of the Love vector soliton are obtained. It is shown that the
properties of the nonlinear Love wave depends on the parameters of the
transition resonance layer, the connected elastic media and the transverse
structure of the Love mode. Numerical investigations of the Love vector soliton
is executed for the parameters of the layered structure ZnO/LiNbO_{3} and
surface acoustic waves which can be reached in current experiments.",1608.05349v1
2016-08-01,Radiation from structured-ring resonators,"We investigate the scalar-wave resonances of systems composed of identical
Neumann-type inclusions arranged periodically around a circular ring. Drawing
on natural similarities with the undamped Rayleigh-Bloch waves supported by
infinite linear arrays, we deduce asymptotically the exponentially small
radiative damping in the limit where the ring radius is large relative to the
periodicity. In our asymptotic approach, locally linear Rayleigh-Bloch waves
that attenuate exponentially away from the ring are matched to a ring-scale
WKB-type wave field. The latter provides a descriptive physical picture of how
the mode energy is transferred via tunnelling to a circular
evanescent-to-propagating transition region a finite distance away from the
ring, from where radiative grazing rays emanate to the far field. Excluding the
zeroth-order standing-wave modes, the position of the transition circle
bifurcates with respect to clockwise and anti-clockwise contributions,
resulting in striking spiral wavefronts.",1608.06477v1
2016-10-26,Single-mode dispersive waves and soliton microcomb dynamics,"Dissipative Kerr solitons are self-sustaining optical wavepackets in
resonators. They use the Kerr nonlinearity to both compensate dispersion and to
offset optical loss. Besides providing insights into nonlinear resonator
physics, they can be applied in frequency metrology, precision clocks, and
spectroscopy. Like other optical solitons, the dissipative Kerr soliton can
radiate power in the form of a dispersive wave through a process that is the
optical analogue of Cherenkov radiation. Dispersive waves typically consist of
an ensemble of optical modes. A limiting case is demonstrated in which the
dispersive wave is concentrated into a single cavity mode. In this limit, its
interaction with the soliton is shown to induce bistable behavior in the
spectral and temporal properties of the soliton. Also, an operating point of
enhanced repetition-rate stability is predicted and observed. The single-mode
dispersive wave can therefore provide quiet states of soliton comb operation
useful in many applications.",1610.08145v1
2017-09-05,Bloch oscillations and resonant radiation of light propagating in arrays of nonlinear fibers with high-order dispersion,"Bloch oscillations of spatio-temporal light wave packets in arrays of
nonlinear fibers with high-order dispersion are studied. The light wave
experiences discrete spatial diffraction along the waveguide array coordinate
together with continuous temporal dispersion including higher order terms. When
a gradient in the waveguide light confinement strength is considered, the wave
packet features robust long-lived Bloch oscillations with temporal and spatial
spreading in the presence of a Kerr nonlinearity. The effect of the spatial
Bloch oscillations on the emission of the dispersive radiation by the solitary
wave is studied. It is shown that Bloch oscillations result in the generation
of new frequencies. The condition of resonant emission of dispersive waves is
derived and it is demonstrated that it matches very well with the results of
direct numerical simulations.",1709.01504v1
2017-11-29,Entanglement studies of resonating valence bonds on the frustrated square lattice,"We study a short-range resonating valence bond (RVB) wave function with
diagonal links on the square lattice that permits sign-problem free wave
function Monte-Carlo studies. Special attention is given to entanglement
properties, in particular, the study of minimum entropy states (MES) according
to the method of Zhang et. al. [Physical Review B {\bf 85}, 235151 (2012)]. We
provide evidence that the MES associated with the RVB wave functions can be
lifted from an associated quantum dimer picture of these wave functions, where
MES states are certain linear combinations of eigenstates of a 't Hooft
""magnetic loop""-type operator. From this identification, we calculate a value
consistent with $\ln(2)$ for the topological entanglement entropy directly for
the RVB states via wave function Monte-Carlo. This corroborates the
$\mathbb{Z}_{2}$ nature of the RVB states. We furthermore define and elaborate
on the concept of a ""pre-Kasteleyn"" orientation that may be useful for the
study of lattices with non-planar topology in general.",1711.10717v1
2017-05-17,Two-dimensional optical plasmons with mixed polarization on anisotropic resonant metasurface,"Optical metasurfaces have great potential to form the platform for
manipulation of surface waves. A plethora of advanced surface-wave phenomena
utilizing negative refraction, self-collimation and channeling of 2D waves can
be realized through on-demand engineering of dispersion properties of a
periodic metasurface. In this letter, we report on the first-time direct
experimental polarization-resolved measurement of dispersion of 2D optical
plasmons supported by an anisotropic metasurface. We demonstrate that a
subdiffractive array of strongly coupled resonant anisotropic plasmonic
nanoparticles supports unusual optical surface waves with mixed TE- and TM-like
polarizations. With the assistance of numerical simulations we identify dipole
and quadrupole dispersion bands. The shape of isofrequency contours changes
drastically with frequency exhibiting nontrivial transformations of their
curvature and topology that is consistently confirmed by the experimental data.
By revealing polarization degree of freedom for surface waves, our results open
new routes for designing of planar on-chip devices for surface photonics.",1705.06078v1
2019-02-07,Anomalous quantum Hall effect of light in Bloch-wave modulated photonic crystals,"Effective magnetic fields have enabled unprecedented manipulation of neutral
particles including photons. In most studied cases, the effective gauge fields
are defined through the phase of mode coupling between spatially discrete
elements, such as optical resonators and waveguides in the case for photons.
Here, in the paradigm of Bloch-wave modulated photonic crystals, we show
creation of effective magnetic fields for photons in conventional dielectric
continua for the first time, via Floquet band engineering. By controlling the
phase and wavevector of Bloch waves, we demonstrated anomalous quantum Hall
effect for light with distinct topological band features due to delocalized
wave interference. Based on a cavity-free architecture, in which Bloch-wave
modulations can be enhanced using guided-resonances in photonic crystals, the
study here opens the door to the realization of effective magnetic fields at
large scales for optical beam steering and topological light-matter phases with
broken time-reversal symmetry.",1902.02887v1
2020-03-25,THz amplification via a Raman scattering,"A THz light amplifier and the corresponding methods are proposed, based on
the Raman interaction between a THz light and visible light lasers. Two lasers,
with their frequencies differing by that of a Langmuir wave, counter-propagate
inside a background plasma, exciting a rather strong Langmuir wave. The THz
light amplification occurs through the non-resonant Raman scattering between
the THz light and one of the lasers in the presence of the mentioned Langmuir
wave. It is normally the case that the non-resonant scattering does not
exchange the energy between E \&M fields but the author demonstrates that it is
possible under the pre-exciting Langmuir wave. In the presence of a
pre-existing Langmuir wave, the ponderomotive density perturbation between the
THz light and the visible-light laser is induced with the phase suitable for
transferring the energy from the visible light laser to the THz light. The
condition for achieving the favorable phase and the amplification strength,
when the condition is met, is estimated as an mathematical formula. The gain is
as high as or even higher than 100 per centimeter.",2004.11125v1
2020-03-31,Dynamical density wave order in an atom-cavity system,"We theoretically and experimentally explore the emergence of a dynamical
density wave order in a driven dissipative atom-cavity system. A Bose-Einstein
condensate is placed inside a high finesse optical resonator and pumped
sideways by an optical standing wave. The pump strength is chosen to induce a
stationary superradiant checkerboard density wave order of the atoms stabilized
by a strong intracavity light field. We show theoretically that, when the pump
is modulated with sufficient strength at a frequency $\omega_{d}$ close to a
systemic resonance frequency $\omega_{>}$, a dynamical density wave order
emerges, which oscillates at the two frequencies $\omega_{>}$ and $\omega_{<} =
\omega_{d} - \omega_{>}$. This order is associated with a characteristic
momentum spectrum, also found in experiments in addition to remnants of the
oscillatory dynamics presumably damped by on-site interaction and heating, not
included in the calculations. The oscillating density grating, associated with
this order, suppresses pump-induced light scattering into the cavity. Similar
mechanisms might be conceivable in light-driven electronic matter.",2003.14135v2
2021-08-31,Space-time wave localization in electromechanical metamaterial beams with programmable defects,"A flexible wave localization is investigated using a spatial-temporal
modulation of point defects along the periodic array of electromechanical local
resonators of a piezoelectric bimorph beam. By changing the electrical
resonance of subsequent unit cells through a smooth and synchronized strategy,
a point defect is moved along the metastructure, which properly transfers the
vibration energy between the unit cells as well as perfectly induces wave
localization according to the final defect position. This wave manipulation by
programmable defects is also applied to a two-dimensional triangular lattice
composed by piezoelectric metamaterial beams, which illustrates the potential
and versatility of the proposed strategy in more complex systems. Therefore,
this work opens new possibilities for programmable wave localization and
manipulation using smart electromechanical metamaterials with applications that
may involve guiding, sensing, monitoring and harvesting.",2108.13742v1
2016-11-27,Edge waves in plates with resonators: An elastic analogue of the quantum valley Hall effect,"We investigate elastic periodic structures characterized by topologically
nontrivial bandgaps supporting backscattering suppressed edge waves. These edge
waves are topologically protected and are obtained by breaking inversion
symmetry within the unit cell. Examples for discrete one and two-dimensional
lattices elucidate the concept and illustrate parallels with the quantum valley
Hall effect. The concept is implemented on an elastic plate featuring an array
of resonators arranged according to a hexagonal topology. The resulting
continuous structures have non-trivial bandgaps supporting edge waves at the
interface between two media having different topological invariants. The
topological properties of the considered configurations are predicted by unit
cell and finite strip dispersion analyses. Numerical simulations on finite
structures demonstrate edge wave propagation for excitation at frequencies
belonging to the bulk bandgaps. The considered plate configurations define a
framework for the implementation of topological concepts on continuous elastic
structures of potential engineering relevance.",1611.08919v2
2017-01-12,Asymptotic Linear Stability of the Benney-Luke equation in 2D,"In this paper, we study transverse linear stability of line solitary waves to
the $2$-dimensional Benney-Luke equation which arises in the study of small
amplitude long water waves in $3$D. In the case where the surface tension is
weak or negligible, we find a curve of resonant continuous eigenvalues near
$0$. Time evolution of these resonant continuous eigenmodes is described by a
$1$D damped wave equation in the transverse variable and it gives a linear
approximation of the local phase shifts of modulating line solitary waves. In
exponentially weighted space whose weight function increases in the direction
of the motion of the line solitary wave, the other part of solutions to the
linearized equation decays exponentially as $t\to\infty$.",1701.03390v1
2017-03-13,Gas dynamics in strong centrifugal fields,"Dynamics of waves generated by scopes in gas centrifuges (GC) for isotope
separation is considered. The centrifugal acceleration in the GC reaches values
of the order of $10^6$g. The centrifugal and Coriolis forces modify essentially
the conventional sound waves. Three families of the waves with different
polarisation and dispersion exist in these conditions. Dynamics of the flow in
the model GC Iguasu is investigated numerically. Comparison of the results of
the numerical modelling of the wave dynamics with the analytical predictions is
performed. New phenomena of the resonances in the GC is found. The resonances
occur for the waves polarized along the rotational axis having the smallest
dumping due to the viscosity.",1703.04451v1
2019-01-11,Three-wave interactions among surface gravity waves in a cylindrical container [DOI],"The motion of a container filled with fluid perturbs the free surface and may
result in spilling. In practice, most of the energy is localized in the modes
of lowest frequencies (the gravest modes), and sloshing can be predicted once
the dynamics of these modes is known. In this Rapid Communication, we
investigate the nonlinear interactions between such grave modes in a
cylindrical container. We first show that energy can be transferred from modes
to modes with three-wave interactions: we derive the resonance conditions and
characterize the early stage of this interaction. This result strongly
contrasts with resonant interactions between surface gravity waves in extended
domains such as the ocean, which involve at least four waves and are thus less
efficient. An experiment is then performed to provide evidence of these
nonlinear interactions.",1901.03549v1
2020-05-17,Quasi-periodic traveling waves on an infinitely deep fluid under gravity,"We consider the gravity water waves system with a periodic one-dimensional
interface in infinite depth and we establish the existence and the linear
stability of small amplitude, quasi-periodic in time, traveling waves. This
provides the first existence result of quasi-periodic water waves solutions
bifurcating from a \emph{completely resonant} elliptic fixed point. The proof
is based on a Nash-Moser scheme, Birkhoff normal form methods and
pseudo-differential calculus techniques. We deal with the combined problems of
\emph{small divisors} and the \emph{fully-nonlinear} nature of the equations.
The lack of parameters, like the capillarity or the depth of the ocean, demands
a refined \emph{nonlinear} bifurcation analysis involving several non-trivial
resonant wave interactions, as the well-known ""Benjamin-Feir resonances"". We
develop a novel normal form approach to deal with that. Moreover, by making
full use of the Hamiltonian structure, we are able to provide the existence of
a wide class of solutions which are free from restrictions of parity in the
time and space variables.",2005.08280v3
2021-01-11,Detection of Gravitational Waves using Parametric Resonance in Bose-Einstein Condensates,"An interesting proposal for detecting gravitational waves involves quantum
metrology of Bose-Einstein condensates (BECs). We consider a forced modulation
of the BEC trap, whose frequency matches that of an incoming continuous
gravitational wave. The trap modulation induces parametric resonance in the
BEC, which in turn enhances sensitivity of the BEC to gravitational waves. We
find that such a BEC detector could potentially be used to detect gravitational
waves across several orders of magnitude in frequency, with the sensitivity
depending on the speed of sound, size of the condensate, and frequency of the
phonons. We outline a possible BEC experiment and discuss the current
technological limitations. We also comment on the potential noise sources as
well as what is necessary for such a detector to become feasible.",2101.03691v2
2021-03-29,The influence of adsorbed atoms concentration on the temperature coefficient of resonant frequency of the quasi-Rayleigh wave,"Within the model of self-consistent connection of quasi-Rayleigh wave with
adsorbed atoms, a method of constructing a new class of radiometric sensors of
the temperature and concentration of adsorbed atoms on the surface acoustic
waves is proposed. Based on the developed theory of the dispersion and acoustic
mode width of a quasi-Rayleigh wave on the adsorbed surface of monocrystals
with a Zinc blende structure, the temperature coefficient of the resonant
frequency of the surface acoustic wave is calculated depending on the
temperature and on the concentration of adsorbed atoms.",2103.15499v1
2021-05-05,Utilizing the Hamiltonian dynamics to study resonant interactions of whistler-mode waves and electrons in the solar wind,"The role of large amplitude whistler waves in the energization and scattering
of solar wind electrons has long been an interesting problem in Space Physics.
To study this wave-particle interaction, we developed a vectorized test
particle simulation with a variational calculation of the Lyapunov exponents.
From using secular perturbation theory on this Hamiltonian system of wave and
particle, we confirmed that the pitch angle diffusion of the particle was along
the constant Hamiltonian surface and that it was driven by the interaction with
the resonance surfaces. We also showed that oblique whistlers could efficiently
scatter field-aligned strahl electrons into the halo population in the solar
wind. We demonstrated through simulation that these waves were capable of
generating horn-like features in the velocity distribution function, similar to
recent PIC simulation results in the literature.",2105.02265v1
2021-12-01,Soliton self-compression and resonant dispersive wave emission in higher-order modes of a hollow capillary fibre,"We investigate soliton self-compression and ultraviolet resonant dispersive
wave emission in the higher-order modes of a gas-filled hollow capillary fibre.
Our simple analytical scaling rules predict shorter required waveguides and
different energy scales when moving from the fundamental to higher-order modes.
Experimentally, we demonstrate soliton self-compression and ultraviolet
dispersive wave emission in the double-lobe LP$_{11}$ mode of an argon-filled
hollow capillary fibre, which we excite by coupling into the fibre at oblique
incidence. We observe the generation of ultraviolet dispersive waves which are
frequency-shifted and more narrowband as compared to fundamental-mode
generation due to the stronger modal dispersion, and a suppression of the
supercontinuum between the dispersive wave and the pump pulse. With numerical
simulations, we confirm the predictions of our scaling rules and find that the
use of higher-order modes can suppress photoionisation and plasma effects even
while allowing for much higher pulse energy to be used in the self-compression
process. Our results add another degree of freedom for the design of
hollow-waveguide systems to generate sub-cycle field transients and tuneable
ultrashort laser pulses.",2112.00369v1
2021-12-24,Nematic dispersive shock waves from nonlocal to local,"The structure of optical dispersive shock waves in nematic liquid crystals is
investigated as the power of the optical beam is varied, with six regimes
identified, which complements previous work pertinent to low power beams only.
It is found that the dispersive shock wave structure depends critically on the
input beam power. In addition, it is known that nematic dispersive shock waves
are resonant and the structure of this resonant is also critically dependent on
the beam power. Whitham modulation theory is used to find solutions for the six
regimes with the existence intervals for each identified. These dispersive
shock wave solutions are compared with full numerical solutions of the nematic
equations and excellent agreement is found.",2112.13114v1
2022-06-16,Nonresonant scattering of relativistic electrons by electromagnetic ion cyclotron waves in Earth's radiation belts,"Electromagnetic ion cyclotron waves are expected to pitch-angle scatter and
cause atmospheric precipitation of relativistic ($> 1$ MeV) electrons under
typical conditions in Earth's radiation belts. However, it has been a
longstanding mystery how relativistic electrons in the hundreds of keV range
(but $<1$ MeV), which are not resonant with these waves, precipitate
simultaneously with those $>1$ MeV. We demonstrate that, when the wave packets
are short, nonresonant interactions enable such scattering of $100$s of keV
electrons by introducing a spread in wavenumber space. We generalize the
quasi-linear diffusion model to include nonresonant effects. The resultant
model exhibits an exponential decay of the scattering rates extending below the
minimum resonant energy depending on the shortness of the wave packets. This
generalized model naturally explains observed nonresonant electron
precipitation in the hundreds of keV concurrent with $>1$ MeV precipitation.",2206.08483v2
2022-07-01,Whistler Waves As a Signature of Converging Magnetic Holes in Space Plasmas,"Magnetic holes are plasma structures that trap a large number of particles in
a magnetic field that is weaker than the field in its surroundings. The
unprecedented high time-resolution observations by NASA's Magnetospheric
Multi-Scale (MMS) mission enable us to study the particle dynamics in magnetic
holes in the Earth's magnetosheath in great detail. We reveal the local
generation mechanism of whistler waves by a combination of Landau-resonant and
cyclotron-resonant wave-particle interactions of electrons in response to the
large-scale evolution of a magnetic hole. As the magnetic hole converges, a
pair of counter-streaming electron beams form near the hole's center as a
consequence of the combined action of betatron and Fermi effects. The beams
trigger the generation of slightly-oblique whistler waves. Our conceptual
prediction is supported by a remarkable agreement between our observations and
numerical predictions from the Arbitrary Linear Plasma Solver (ALPS). Our study
shows that wave-particle interactions are fundamental to the evolution of
magnetic holes in space and astrophysical plasmas.",2207.00273v1
2022-10-11,Linear and Nonlinear Disturbance Evolution on the Frustum of Hypersonic Ogive-Cylinders,"Aspects of transition mechanisms on a $14^{\circ}$ sharp-nosed ogive-cylinder
at Mach~$6$ are elucidated by considering linear and nonlinear disturbance
evolution of freestream stochastic and wave packet forcing at different
locations downstream of the ogive-cylinder junction. The spectral response of
the stochastic forcing displays favorable agreement with experimental
observations from AFRL on which the configuration is based. Intermittent wave
packets are generated from small-amplitude continuous freestream pressure
forcing. Linear wave packet evolution reveals that Mack modes are the dominant
primary instabilities, followed by relatively weaker first-mode waves. The
non-linear wavepacket displays a three-legged wall pressure perturbation
signature, which is traced to spanwise curvature effects, and fundamental
resonance is the dominant secondary instability mechanism. At higher amplitudes
of excitation, weak signatures of sub-harmonic and oblique resonance phenomena
are identified. Downstream placement of the small-amplitude disturbance
diminishes receptivity of first-mode waves; however, with high-amplitude
forcing, the location of actuation does not significantly vary the disturbance
evolution signature or the secondary instability mechanisms.",2210.05069v1
2023-04-12,Understanding oscillons: standing waves in a ball,"Oscillons are localised long-lived pulsating states in the three-dimensional
$\phi^4$ theory. We gain insight into the spatio-temporal structure and
bifurcation of the oscillons by studying time-periodic solutions in a ball of a
finite radius. A sequence of weakly localised {\it Bessel waves} -- nonlinear
standing waves with the Bessel-like $r$-dependence -- is shown to extend from
eigenfunctions of the linearised operator. The lowest-frequency Bessel wave
serves as a starting point of a branch of periodic solutions with exponentially
localised cores and small-amplitude tails decaying slowly towards the surface
of the ball. A numerical continuation of this branch gives rise to the
energy-frequency diagram featuring a series of resonant spikes. We show that
the standing waves associated with the resonances are born in the
period-multiplication bifurcations of the Bessel waves with higher frequencies.
The energy-frequency diagram for a sufficiently large ball displays sizeable
intervals of stability against spherically-symmetric perturbations.",2304.05911v1
2023-06-21,Phononic graded meta-MEMS for elastic wave amplification and filtering,"Inspired by recent graded metamaterials designs, we create phononic arrays of
micro-resonators for frequency signal amplification and wave filtering.
Leveraging suspended waveguides on a thick silicon substrate, we hybridize
surface Rayleigh and Lamb flexural waves to effectively achieve phononic signal
control along predefined channels. The guided waves are then spatially
controlled using a suitable grading of the micro-resonators, which provide high
signal-to-noise ratio and simultaneously create phononic delay-lines. The
proposed device can be used for sensing, wave filtering or energy harvesting.",2306.12076v1
2023-08-14,Comment on `Painlevé Integrability and Multi-wave pattern for (2+1) dimensional Long wave-Short wave Resonance Interaction system',"In the paper by Sivatharani et al [1], the authors make a tall claim about
the integrability of a 2 component (2+1) dimensional Long wave Short wave
Resonance Interaction (2C(2+1)LSRI) equation with mixed sign which was already
claimed to be non integrable and hence known not to satisfy Painlev\'e [2]
property which the authors show to pass Painlev\'e test. We have categorically
shown how the system does not pass Painlev\'e test and hence non-integrable
reinforcing the claim made by Maruno et al [2]. The authors claim to derive the
solutions of 2C(2+1)LSRI equation which ironically do not satisfy the equation.
To top it all, the authors claim to have generated lumps and dromions which
again defy their very own definition.",2308.07043v1
2023-09-26,Comparison of $\bar{\hbox{N}}\hbox{N}$ optical models,"We compare the strong part of the $\bar{\hbox{N}}\hbox{N}$ interaction
obtained by the Nijmegen partial wave analysis and the results of some of the
most popular $\bar{\hbox{N}}\hbox{N}$ optical potentials in configuration
space. We have found severe discrepancies in most of the partial waves,
especially above $p_{Lab}$=400 MeV/c where the partial wave analysis displays a
resonant-like structure in the $^{31}$S$_0$ and $^{33}$P$_0$ waves. Some
theoretical difficulties to interpret this behaviour in terms of dynamical
resonances are pointed pout and an alternative explanation is suggested. A much
better stability is observed in the low energy parameters, apart from some
discrepancies due to the presence of near-threshold quasi-bound states in
particular waves. Large deviations have also been found between the
corresponding potentials, at short and medium-range ($r\gtrsim 1$ fm)
distances.",2309.14831v1
2023-10-19,Locally Resonant Metagrating by Elastic Impedance Modulation,"The optical and acoustic metagratings have addressed the limitations of
low-efficiency wave manipulation and high-complexity fabrication of
metamaterials and metasurfaces. In this research, we introduce the concept of
elastic metagrating and present the theoretical and experimental demonstration
of locally resonant elastic metagrating (LREM). Remarkably, the LREM, with
dimensions two orders of magnitude smaller than the relevant wavelength,
overcomes the size limitations of conventional metagratings and offers a unique
design paradigm for highly efficient wave manipulation with an extremely
compact structure in elastic wave systems. Based on a distinctive elastic
impedance engineering with hybridization of intrinsic evanescent waves, the
proposed LREM achieves wide-angle perfect absorption. This tackles a
fundamental challenge faced by all elastic metastructures designed for wave
manipulation, which consists in the unavoidable vibration modes in finite
structures hindering their implementations in real-world applications.",2310.12756v1
2023-10-25,Optimal control for manipulating vibrational wave packets through polarizability interactions induced by non-resonant laser pulses,"On the basis of optimal control theory, we numerically study how to optimally
manipulate molecular vibrational dynamics by using cycle-averaged
polarizability interactions induced by mildly intense non-resonant laser (NR)
pulses. As the essential elements to be controlled are the probability
amplitudes, namely, the populations and the relative phases of the vibrational
eigenstates, we consider three fundamental control objectives: selective
population transfer, wave packet shaping that requires both population control
and relative-phase control, and wave packet deformation suppression that solely
requires relative-phase control while avoiding population redistribution. The
non-trivial control of wave packet deformation suppression is an extension of
our previous study on wave packet spreading suppression. Focusing on the
vibrational dynamics in the B state of I2 as a case study, we adopt optimal
control simulations and model analyses under the impulsive excitation
approximation to systematically examine how to achieve the control objectives
with shaped NR pulses. Optimal solutions are always given by NR pulse trains,
in which each pulse interval and each pulse intensity are adjusted to cooperate
with the vibrational dynamics to effectively utilize the quantum interferences
to realize the control objectives with high probability.",2310.16440v1
2013-01-14,Polarised Electromagnetic wave propagation through the ferromagnet: Phase boundary of dynamic phase transition,"The dynamical responses of ferromagnet to the propagating electromagnetic
field wave passing through it are modelled and studied here by Monte Carlo
simulation in two dimensional Ising ferromagnet. Here, the electromagnetic wave
is linearly polarised in such a way that the direction of magnetic field is
parallel to that of the magnetic momemts (spins). The coherent propagating mode
of spin-clusters is observed. The time average magnetisation over the full
cycle (time) of the field defines the order parameter of the dynamic
transition. Depending on the value of the temperature and the amplitude of the
propagating magnetic field wave, a dynamical phase transition is observed. The
dynamic transition was detected by studying the temperature dependences of the
dynamic order parameter, the variance of the dynamic order parameter, the
derivative of the dynamic order parameter and the dynamic specific heat. The
phase boundaries of the dynamic transitions were drawn for two different values
of the wave lengths of the propagating magnetic field wave. The phase boundary
was observed to shrink (inward) for lower speed of propagation of the EM wave.
The divergence of the releavant length scale was observed at the transition
point.",1301.3071v2
2016-02-18,Atom-light superposition oscillation and Ramsey-like atom-light interferometer,"Coherent wave splitting is crucial in interferometers. Normally, the waves
after this splitting are of the same type. But recent progress in interaction
between atom and light has led to the coherent conversion of photon to atomic
excitation. This makes it possible to split an incoming light wave into a
coherent superposition state of atom and light and paves the way for an
interferometer made of different types of waves. Here we report on a Rabi-like
coherent-superposition oscillation observed between atom and light and a
coherent mixing of light wave with excited atomic spin wave in a Raman process.
We construct a new kind of hybrid interferometer based on the atom-light
coherent superposition state. Interference fringes are observed in both optical
output intensity and atomic output in terms of the atomic spin wave strength
when we scan either or both of the optical and atomic phases. Such a hybrid
interferometer can be used to interrogate atomic states by optical detection
and will find its applications in precision measurement and quantum control of
atoms and light.",1602.05685v1
2021-06-10,Steering visible Dyakonov surface waves at the hyperbolic metasurface,"Dyakonov surface wave existing at the interface with anisotropy offers a
promising way of guiding light in two-dimension with almost no loss. However,
predicted decades ago, the experimental demonstration of the Dyakonov surface
wave seems always challenging for the weak anisotropic indices from the natural
materials. Here we experimentally demonstrated a Dyakonov surface wave mode
propagating in a hyperbolic metasurface at the visible frequency. Dyakonov
surface waves at the two surfaces of the metasurface can be supported
simultaneously by the hyperbolic anisotropy and form a Dyakonov typed mode with
low loss and a large allowed angle band. A detailed theoretical analysis and
numerical simulations prove that the electric field of such a surface wave mode
shows transverse spin, whose direction is determined by the orientations of the
hyperbolic anisotropy and surface normal, based on which we experimentally
observed the photonic spin Hall effect of the surface wave mode in our
metasurface.",2106.05699v1
1993-09-02,"MATTERS OF GRAVITY, a newsletter for the gravity community, number 2","Table of contents:
  Editorial 1
  Correspondents 3
  Some recent work in general relativistic Astrophysics 4
  Two dimensional black holes 6
  Resonant-mass gravitational wave detectors: an update 8
  Universality and scaling in gravitational collapse 9
  Gravitational Wave memories upgraded 11
  Conference report: quantum aspects of black holes 13
  Conference report: knots and quantum gravity 14
  Conference report: deterministic chaos in GR 17",9309003v1
2000-05-19,Detection of Scalar Gravitational Waves,"In this talk I review recent progresses in the detection of scalar
gravitational waves. Furthermore, in the framework of the Jordan-Brans-Dicke
theory, I compute the signal to noise ratio for a resonant mass detector of
spherical shape and for binary sources and collapsing stars. Finally I compare
these results with those obtained from laser interferometers and from
Einsteinian gravity.",0005089v1
2000-11-07,Scattering by Black Holes,"This is a chapter on Black-hole Scattering that was commissioned for an
Encyclopaedia on Scattering edited by Pike and Sabatier, to be published by
Academic Press. The chapter surveys wave propagation in black-hole spacetimes,
diffraction effects in wave scattering, resonances, quasinormal modes and
related topics.",0011025v2
2004-10-29,Forced vibrations of wave equations with non-monotone nonlinearities,"We prove existence and regularity of periodic in time solutions of completely
resonant nonlinear forced wave equations with Dirichlet boundary conditions for
a large class of non-monotone forcing terms. Our approach is based on a
variational Lyapunov-Schmidt reduction. It turns out that the infinite
dimensional bifurcation equation exhibits an intrinsic lack of compactness. We
solve it via a minimization argument and a-priori estimate methods inspired to
regularity theory of Rabinowitz",0410619v1
2005-12-02,Periodic solutions of wave equations for asymptotically full measure sets of frequencies,"We prove existence and multiplicity of small amplitude periodic solutions of
the completely resonant wave equation u_tt - u_xx + f(x,u)=0 with Dirichlet
boundary conditions where f(x,u)=a_2 u^2 + a_3(x) u^3 + O(u^4) or f(x,u)= a_4
u^4 + O(u^5) for a Cantor-like set of frequencies omega of asymptotically full
measure at omega=1.",0512053v1
2005-07-20,Discreteness and its effect on the water-wave turbulence,"We perform numerical simulations of the dynamical equations for free water
surface in finite basin in presence of gravity. Wave Turbulence (WT) is a
theory derived for describing statistics of weakly nonlinear waves in the
infinite basin limit. Its formal applicability condition on the minimal size of
the computational basin is impossible to satisfy in present numerical
simulations, and the number of wave resonances is significantly depleted due to
the wavenumber discreteness. The goal of this paper will be to examine which WT
predictions survive in such discrete systems with depleted resonances and which
properties arise specifically due to the discreteness effects. As in
\cite{DKZ,onorato,naoto}, our results for the wave spectrum agree with the
Zakharov-Filonenko spectrum predicted within WT. We also go beyond finding the
spectra and compute probability density function (PDF) of the wave amplitudes
and observe an anomalously large, with respect to Gaussian, probability of
strong waves which is consistent with recent theory \cite{clnp,cln}. Using a
simple model for quasi-resonances we predict an effect arising purely due to
discreteness: existence of a threshold wave intensity above which turbulent
cascade develops and proceeds to arbitrarily small scales. Numerically, we
observe that the energy cascade is very ``bursty'' in time and is somewhat
similar to sporadic sandpile avalanches. We explain this as a cycle: a cascade
arrest due to discreteness leads to accumulation of energy near the forcing
scale which, in turn, leads to widening of the nonlinear resonance and,
therefore, triggering of the cascade draining the turbulence levels and
returning the system to the beginning of the cycle. ~",0507054v5
1996-06-24,Ambiguities in the partial-wave analysis of pseudoscalar-meson photoproduction,"Ambiguities in pseudoscalar-meson photoproduction, arising from incomplete
experimental data, have analogs in pion-nucleon scattering. Amplitude
ambiguities have important implications for the problems of amplitude
extraction and resonance identification in partial-wave analysis. The effect of
these ambiguities on observables is described. We compare our results with
those found in earlier studies.",9606052v1
1998-06-17,Effective field theory of resonant 2-level atoms,"The phenomenological two-level atom is re-analysed using the methods of
effective field theory. By presenting the Dicke-Jaynes-Cummings model in real
space, an exact diagonalization is accomplished going beyond the rotating wave
approximation. The meaning of the symmetries and conserved quantities in the
theory is discussed and the model is related to non-equilibrium field theory.
The structure of the solution raises a question about the rotating wave
approximation in quantum mechanics.",9806057v1
2002-09-25,Dynamical suppression of radiative decay via atomic deflection by a standing light wave,"We consider the radiative decay of atoms scattered by a resonant standing
light wave. Scattering is shown to suppress the Rabi oscillations and to slow
down the atomic radiative decay giving rise to a power law behavior of the
time-dependent level populations rather than the exponential one.",0209134v1
2007-04-26,Low frequency dispersive estimates for the wave equation in higher dimensions,"We prove dispersive estimates at low frequency in dimensions n greater or
equal to 4 for the wave equation for a very large class of real-valued
potentials, provided the zero is neither an eigenvalue nor a resonance.",0704.3556v4
2008-04-20,Fano-Type Resonance of Waves in Periodic Slabs,"We investigate Fano-type anomalous transmission of energy of plane waves
across lossless slab scatterers with periodic structure in the presence of
non-robust guided modes. Our approach is based on rigorous analytic
perturbation of the scattering problem near a guided mode and applies to very
general structures, continuous and discrete.",0804.3148v1
2009-06-29,Global Solutions for the Gravity Water Waves Equation in Dimension 3,"We show existence of global solutions for the gravity water waves equation in
dimension 3, in the case of small data. The proof combines energy estimates,
which yield control of L^2 related norms, with dispersive estimates, which give
decay in L^\infty. To obtain these dispersive estimates, we use an analysis in
Fourier space; the study of space and time resonances is then the crucial
point.",0906.5343v1
2010-05-12,Continuous-wave spontaneous lasing in mercury pumped by resonant two-photon absorption,"The first continuous-wave two-photon absorption laser-induced stimulated
emission (CTALISE) is demonstrated. The 7^1S-6^1P transition in mercury at
1014nm wavelength is used and selective lasing of different isotopes is
observed.",1005.2098v2
2011-02-21,Global Strichartz estimates for the wave equation with a time-periodic non-trapping metric,"We obtain global Strichartz estimates for the solution $u$ of the wave
equation $\partial_t^2 u-\Div_x(a(t,x)\nabla_xu)=0$ with time-periodic metric
$a(t,x)$ equal to 1 outside a compact set with respect to $x$. We assume
$a(t,x)$ is a non-trapping perturbation and moreover, we suppose that there are
no resonances $z_j\in\mathbb{C}$ with $|z_j|\geq1$.",1102.4169v1
2011-05-01,Ultrabright Backward-wave Biphoton Source,"We calculate the properties of a biphoton source based on resonant
backward-wave spontaneous parametric down-conversion. We show that the
biphotons are generated in a single longitudinal mode having a subnatural
linewidth and a Glauber correlation time exceeding 65 ns.",1105.0144v1
2012-10-04,Global existence for capillary water waves,"Consider the capillary water waves equations, set in the whole space with
infinite depth, and consider small data (i.e. sufficiently close to zero
velocity, and constant height of the water). We prove global existence and
scattering. The proof combines in a novel way the energy method with a cascade
of energy estimates, the space-time resonance method and commuting vector
fields.",1210.1601v1
2012-12-10,Explicit formulas for the Schroedinger wave operators in R^2,"In this note, we derive explicit formulas for the Schroedinger wave operators
in R^2 under the assumption that 0-energy is neither an eigenvalue nor a
resonance. These formulas justify the use of a recently introduced topological
approach of scattering theory to obtain index theorems.",1212.2230v1
2014-12-05,Numerical investigation of acoustic solitons,"Acoustic solitons can be obtained by considering the propagation of large
amplitude sound waves across a set of Helmholtz resonators. The model proposed
by Sugimoto and his coauthors has been validated experimentally in previous
works. Here we examine some of its theoretical properties: low-frequency
regime, balance of energy, stability. We propose also numerical experiments
illustrating typical features of solitary waves.",1412.1985v1
2015-06-05,Decay estimates for the wave equation in two dimensions,"We establish Strichartz estimates (both reversed and some direct ones),
pointwise decay estimates, and weighted decay estimates for the linear wave
equation in dimension two with an almost scaling-critical potential, in the
case when there is no resonance or eigenvalue at the edge of the spectrum.
  We also prove some simple nonlinear applications.",1506.01832v2
2019-05-31,Energy transfer model and large periodic boundary value problem for the quintic nonlinear Schrodinger equations,"We study a dynamics and energy exchanges between a linear oscillator and a
nonlinear interaction state for the one dimensional, quintic nonlinear
Schrodinger equation. Grebert and Thomann proved that there exist solutions
with initial data built on four Fourier modes, that confirms the conservative
exchange of wave energy. Captured multi resonance in multiple Fourier modes, we
simulate a similar energy exchange in long-period waves.",1905.13680v1
2008-12-28,Orbital resonances in discs around braneworld Kerr black holes,"Rotating black holes in the brany universe of the Randall-Sundrum type are
described by the Kerr geometry with a tidal charge b representing the
interaction of the brany black hole and the bulk spacetime. For b<0 rotating
black holes with dimensionless spin a>1 are allowed. We investigate the role of
the tidal charge b in the orbital resonance model of QPOs in black hole
systems. The orbital Keplerian, the radial and vertical epicyclic frequencies
of the equatorial, quasicircular geodetical motion are given and their radial
profiles are discussed. The resonant conditions are given in three
astrophysically relevant situations: for direct (parametric) resonances, for
the relativistic precession model, and for some trapped oscillations of the
warped discs, with resonant combinational frequencies. It is shown, how b could
influence matching of the observational data indicating the 3:2 frequency ratio
observed in GRS 1915+105 microquasar with prediction of the orbital resonance
model; limits on allowed range of the black hole parameters a and b are
established. The ""magic"" dimensionless black hole spin enabling presence of
strong resonant phenomena at the radius where \nu_K:\nu_{\theta}:\nu_r=3:2:1 is
determined in dependence on b. Such strong resonances could be relevant even in
sources with highly scattered resonant frequencies, as those expected in Sgr
A*. The specific values of a and b are given also for existence of specific
radius where \nu_K:\nu_{\theta}:\nu_r=s:t:u with 5>=s>t>u being small natural
numbers. It is shown that for some ratios such situation is impossible in the
field of black holes. We can conclude that analysing the microquasars
high-frequency QPOs in the framework of orbital resonance models, we can put
relevant limits on the tidal charge of brany Kerr black holes.",0812.5066v1
1994-06-27,Quantum Phase Transition in the Frustrated Heisenberg Antiferromagnet,"Using the J_1-J_2 model, we present a description of quantum phase transition
from Neel ordered to the spin-liquid state based on the modified spin wave
theory. The general expression for the gap in the spectrum in the spin-liquid
phase is presented.",9406106v2
1996-02-15,Spectral properties of Luther-Emery systems,"We calculate the spectral function of the Luther-Emery model which describes
one-dimensional fermions with gapless charge and gapped spin degrees of
freedom. We find a true singularity with interaction dependent exponents on the
gapped spin dispersion and a finite maximum depending on the magnitude of the
spin gap, on a shifted charge dispersion. We apply these results to
photoemission experiments on charge density wave systems and discuss the
spectral properties of a one-dimensional Mott insulator.",9602087v1
1998-07-22,Spin excitations in ferromagnetic manganites,"An effective one-band Hamiltonian for colossal-magnetoresistance (CMR)
manganites is constructed and the spin excitations are determined. Fitting the
experimental data by the derived spin-wave dispersion gives an e_g -electron
hopping amplitude of about 0.2 eV in agreement with LDA band calculations.",9807294v1
2001-08-05,Low Energy Behaviour of XXZ Antiferromagnetic Spin Chain,"Zero temperature phase diagram of XXZ spin chain in external magnetic field
is investigated at low energies using path integral approach.It has been shown
by spin wave analysis and then by nonlinear sigma model transformation that
below some critical field the system undergoes quantum Kosterlitz-Thouless
phase transition.Above that critical field for low anisotropies the system is
saturated while at strong anisotropy the system has Ising antiferromagnetic
order.",0108086v1
2003-01-30,"The Mixed Spin S=(1/2,1) XXZ Ferrimagnet at Zero Temperature","Linked cluster series expansions about the Ising limit are used to study
ground state preperties, viz. ground state energy, magnetization and excitation
spectra, for mixed spin S=(1/2,1) quantum ferrimagnets on simple bipartite
lattices in 1, 2, and 3-dimensions. Results are compared to second-order spin
wave theory and, in general, excellent agreement is obtained.",0301580v1
2005-11-11,Spin current as a response to external stress,"It is theoretically predicted that a traveling shear wave will create a spin
current in certain direct-gap (for example III-V compound) semiconductors with
contributions from both the valence bands and the conduction band (for
$n$-doped semiconductors). We show that this spin-current is a property of the
Fermi-Dirac sea, and is controlled by a geometric phase accumulated by the
strain-induced Rashba parameters in a cycle.",0511270v1
1997-03-25,Post-Newtonian Approximation for Spinning Particles,"Using an energy-momentum tensor for spinning particles due to Dixon and
Bailey-Israel, we develop the post-Newtonian approximation for N spinning
particles in a self-contained manner. The equations of motion are derived
directly from this energy-momentum tensor. Following the formalism of Epstein-
Wagoner, we also obtain the waveform and the luminosity of the gravitational
wave generated by these particles.",9703071v1
2007-09-06,Spin-gravity coupling and gravity-induced quantum phases,"External gravitational fields induce phase factors in the wave functions of
particles. The phases are exact to first order in the background gravitational
field, are manifestly covariant and gauge invariant and provide a useful tool
for the study of spin-gravity coupling and of the optics of particles in
gravitational or inertial fields. We discuss the role that spin-gravity
coupling plays in particular problems.",0709.0819v1
2009-04-09,Interacting two helical edge modes in quantum spin Hall systems,"We study theoretically the two interacting one-dimensional helical modes at
the edges of the quantum spin Hall systems. A new type of inter-edge correlated
liquid (IECL) without the spin gap is found. This liquid shows the diverging
density wave (DW) and superconductivity (SC) correlations much stronger than
those of the spinfull electrons. Possible experimental observations are also
discussed.",0904.1453v2
2009-12-31,Spin light mode of massive neutrino radiative decay in matter,"Using the exact solutions for the Dirac neutrino wave function in presence of
matter we study the spin light mode in the process of neutrino transition from
initial heavier to final lighter state. The spin light is emitted due to the
neutrino nonzero transitional magnetic moment.",1001.0101v1
2012-11-26,Electron spin motion in the delta-function pulse,"We formulate the Bargman-Michel-Telegdi (BMT) equation for electron spin
motion in a plane wave and in the Dirac delta-function pulse. We compare the
BMT solution with the Wolkow solution of the Dirac equation. The Wolkow
solution for the spin is not identical with the solution following from the BMT .",1211.5889v1
2016-01-29,The B-ring's surface mass density from hidden density waves: Less than meets the eye?,"Saturn's B ring is the most opaque ring in our solar system, but many of its
fundamental parameters, including its total mass, are not well constrained.
Spiral density waves generated by mean-motion resonances with Saturn's moons
provide some of the best constraints on the rings' mass density, but detecting
and quantifying such waves in the B ring has been challenging because of this
ring's high opacity and abundant fine-scale structure. Using a wavelet-based
analyses of 17 occultations of the star gamma Crucis observed by the Visual and
Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft, we are
able to examine five density waves in the B ring. Two of these waves are
generated by the Janus 2:1 and Mimas 5:2 Inner Lindblad Resonances at 96,427 km
and 101,311 km from Saturn's center, respectively. Both of these waves can be
detected in individual occultation profiles, but the multi-profile wavelet
analysis reveals unexpected variations in the pattern speed of the Janus 2:1
wave that might arise from the periodic changes in Janus' orbit. The other
three wave signatures are associated with the Janus 3:2, Enceladus 3:1 and
Pandora 3:2 Inner Lindblad Resonances at 115,959 km, 115,207 km and 108,546 km.
These waves are not visible in individual profiles, but structures with the
correct pattern speeds can be detected in appropriately phase-corrected average
wavelets. Estimates of the ring's surface mass density derived from these five
waves fall between 40 and 140 g/cm^2, even though the ring's optical depth in
these regions ranges from 1.5 to almost 5. This suggests that the total mass of
the B ring is most likely between one-third and two-thirds the mass of Saturn's
moon Mimas.",1601.07955v2
2017-02-07,Dimensionless scaling of heat-release-induced planar shock waves in near-critical CO2,"We performed highly resolved one-dimensional fully compressible Navier-Stokes
simulations of heat-release-induced compression waves in near-critical CO2. The
computational setup, inspired by the experimental setup of Miura et al., Phys.
Rev. E, 2006, is composed of a closed inviscid (one-dimensional) duct with
adiabatic hard ends filled with CO2 at three supercritical pressures. The
corresponding initial temperature values are taken along the pseudo-boiling
line. Thermodynamic and transport properties of CO2 in near-critical conditions
are modeled via the Peng-Robinson equation of state and Chung's Method. A heat
source is applied at a distance from one end, with heat release intensities
spanning the range 10^3-10^11 W/m^2, generating isentropic compression waves
for values < 10^9 W/m^2. For higher heat-release rates such compressions are
coalescent with distinct shock-like features (e.g. non-isentropicity and
propagation Mach numbers measurably greater than unity) and a non-uniform
post-shock state is present due to the strong thermodynamic nonlinearities. The
resulting compression wave intensities have been collapsed via the thermal
expansion coefficient, highly variable in near-critical fluids, used as one of
the scaling parameters for the reference energy. The proposed scaling applies
to isentropic thermoacoustic waves as well as shock waves up to shock strength
2. Long-term time integration reveals resonance behavior of the compression
waves, raising the mean pressure and temperature at every resonance cycle. When
the heat injection is halted, expansion waves are generated, which counteract
the compression waves leaving conduction as the only thermal relaxation
process. In the long term evolution, the decay in amplitude of the resonating
waves observed in the experiments is qualitatively reproduced by using
isothermal boundary conditions.",1702.01832v1
2006-04-10,Polarization Transport of Transverse Acoustic Waves: Berry Phase and Spin Hall Effect of Phonons,"We carry out a detailed analysis of the short-wave (semiclassical)
approximation for the linear equations of the elasticity in a smoothly
inhomogeneous isotropic medium. It is shown that the polarization properties of
the transverse waves are completely analogous to those of electromagnetic waves
and can be considered as spin properties of optical phonons. In particular, the
Hamiltonian of the transverse waves contains an additional term of the phonon
spin-orbit interaction arising from the Berry gauge potential in the momentum
space. This potential is diagonal in the basis of the circularly polarized
waves and corresponds to the field of two `magnetic monopoles' of opposite
signs for phonons of opposite helicities. This leads to the appearance of the
Berry phase in the equation for the polarization evolution and an additional
``anomalous velocity'' term in the ray equations. The anomalous velocity has
the form of the `Lorentz force' caused by the Berry gauge field in momentum
space and gives rise to the transverse transport of waves of opposite
helicities in opposite directions. This is a manifestation of the spin Hall
effect of optical phonons. The effect directly relates to the conservation of
total angular momentum of phonons and also influences reflection from a sharp
boundary (acoustic analogue of the transverse Ferdorov--Imbert shift).",0604248v4
2019-04-10,Optical excitation of propagating magnetostatic waves in an epitaxial Galfenol film by an ultrafast magnetic anisotropy change,"Using a time-resolved optically-pumped scanning optical microscopy technique
we demonstrate the laser-driven excitation and propagation of spin waves in a
20-nm film of a ferromagnetic metallic alloy Galfenol epitaxially grown on a
GaAs substrate. In contrast to previous all-optical studies of spin waves we
employ laser-induced thermal changes of magnetocrystalline anisotropy as an
excitation mechanism. A tightly focused 70-fs laser pulse excites packets of
magnetostatic surface waves with a $e^{-1}$ propagation length of 3.4 $\mu$m,
which is comparable with that of permalloy. As a result, laser-driven
magnetostatic spin waves are clearly detectable at distances up to 10 $\mu$m,
which promotes epitaxial Galfenol films to the limited family of materials
suitable for magnonic devices. A pronounced in-plane magnetocrystalline
anisotropy of the Galfenol film offers an additional degree of freedom for
manipulating the spin waves' parameters. Reorientation of an in-plane external
magnetic field relative to the crystallographic axes of the sample tunes the
frequency, amplitude and propagation length of the excited waves.",1904.05171v2
2020-06-15,Gravitational shock waves and scattering amplitudes,"We study gravitational shock waves using scattering amplitude techniques.
After first reviewing the derivation in General Relativity as an
ultrarelativistic boost of a Schwarzschild solution, we provide an alternative
derivation by exploiting a novel relation between scattering amplitudes and
solutions to Einstein's field equations. We prove that gravitational shock
waves arise from the classical part of a three point function with two massless
scalars and a graviton. The region where radiation is localized has a
distributional profile and it is now recovered in a natural way, thus bypassing
the introduction of singular coordinate transformations as used in General
Relativity. The computation is easily generalized to arbitrary dimensions and
we show how the exactness of the classical solution follows from the absence of
classical contributions at higher loops. A classical double copy between
gravitational and electromagnetic shock waves is also provided and for a
spinning source, using the exponential form of three point amplitudes, we infer
a remarkable relation between gravitational shock waves and spinning ones, also
known as gyratons. Using this property, we infer a family of exact solutions
describing gravitational shock waves with spin. We then compute the phase shift
of a particle in a background of shock waves finding agreement with an earlier
computation by Amati, Ciafaloni and Veneziano for particles in the high energy
limit. Applied to a gyraton, it provides a result for the scattering angle to
all orders in spin.",2006.08283v2
2024-04-16,Reconfigurable spin-wave platform based on interplay between nanodots and waveguide in hybrid magnonic crystal,"We present a hybrid magnonic crystal composed of a chain of nanodots with
strong perpendicular magnetic anisotropy and Dzyaloshinskii-Moriya interaction,
positioned above a permalloy waveguide. The study examines two different
magnetization states in the nanodots: a single-domain state and an egg-shaped
skyrmion state. Due to the dipolar coupling between the dot and the waveguide,
a strongly bound hybrid magnetization texture is formed in the system. Our
numerical results show complex spin-wave spectra, combining the effects of
periodicity, magnetization texture, and hybridization of the propagating waves
in the waveguide with the dot/skyrmion modes. The systems are characterized by
different band gap sizes. For the skyrmion state, the azimuthal modes confined
to the skyrmion domain wall lead to the formation of flat bands at low
frequencies, while at higher frequencies we identify among them modes
interacting with the propagating waves, which can introduce additional
non-Bragg band gaps, as well as isolated modes leading to the formation of
bound states. On the other hand, the system with a single-domain state in
nanodots offers a wide range of frequencies where the spin waves are
predominantly in the waveguide. Thus, the study shows that the proposed hybrid
magnonic crystals have many distinct functionalities, highlighting their
reconfigurable potential, magnon-magnon couplings, mode localization, and bound
states overlapping with the propagating waves. This opens up potential
applications in analog and quantum magnonics, spin-wave filtering, and the
establishment of magnonic neural networks.",2404.10493v1
2018-08-10,Gravitational-Wave Geodesy: A New Tool for Validating Detection of the Stochastic Gravitational-Wave Background,"A valuable target for advanced gravitational-wave detectors is the stochastic
gravitational-wave background. The stochastic background imparts a weak
correlated signal into networks of gravitational-wave detectors, and so
standard searches for the gravitational-wave background rely on measuring
cross-correlations between pairs of widely-separated detectors. Stochastic
searches, however, can be affected by any other correlated effects which may
also be present, including correlated frequency combs and magnetic Schumann
resonances. As stochastic searches become sensitive to ever-weaker signals, it
is increasingly important to develop methods to separate a true astrophysical
signal from other spurious and/or terrestrial signals. Here, we describe a
novel method to achieve this goal -- gravitational-wave geodesy. Just as radio
geodesy allows for the localization of radio telescopes, so too can
observations of the gravitational-wave background be used to infer the
positions and orientations of gravitational-wave detectors. By demanding that a
true observation of the gravitational-wave background yield constraints
consistent with the baseline's known geometry, we demonstrate that we can
successfully validate true observations of the gravitational-wave background
while rejecting spurious signals due to correlated terrestrial effects.",1808.03716v3
2019-12-11,Tailored elastic surface to body wave Umklapp conversion,"Elastic waves guided along surfaces dominate applications in geophysics,
ultrasonic inspection, mechanical vibration, and surface acoustic wave devices;
precise manipulation of surface Rayleigh waves and their coupling with
polarized body waves presents a challenge that offers to unlock the flexibility
in wave transport required for efficient energy harvesting and vibration
mitigation devices. We design elastic metasurfaces, consisting of a graded
array of rod resonators attached to an elastic substrate that, together with
critical insight from Umklapp scattering in phonon-electron systems, allow us
to leverage the transfer of crystal momentum; we mode-convert Rayleigh surface
waves into bulk waves that form tunable beams. Experiments, theory and
simulation verify that these tailored Umklapp mechanisms play a key role in
coupling surface Rayleigh waves to reversed bulk shear and compressional waves
independently, thereby creating passive self-phased arrays allowing for tunable
redirection and wave focusing within the bulk medium.",1912.05373v1
2020-10-23,Possible coexistence of kinetic Alfvén and ion Bernstein modes in sub-ion scale compressive turbulence in the solar wind,"We investigate compressive turbulence at sub-ion scales with measurements
from the Magnetospheric MultiScale Mission. The tetrahedral configuration and
high time resolution density data obtained by calibrating spacecraft potential
allow an investigation of the turbulent density fluctuations in the solar wind
and their three-dimensional structure in the sub-ion range. The wave-vector
associated with the highest energy density at each spacecraft frequency is
obtained by application of the Multi-point signal resonator technique to the
four-point density data. The fluctuations show a strong wave-vector anisotropy
$k_{\perp}\gg k_{\parallel}$ where the parallel and perpendicular symbols are
with respect to the mean magnetic field direction. The plasma frame frequencies
show two populations, one below the proton cyclotron frequency
$\omega<\Omega_{ci}$ consistent with kinetic Alfv\'en wave (KAW) turbulence.
The second component has higher frequencies $\omega > \Omega_{ci}$ consistent
with ion Bernstein wave (IBW) turbulence. Alternatively, these fluctuations may
constitute KAWs that have undergone multiple wave-wave interactions causing a
broadening in the plasma frame frequencies. The scale-dependent kurtosis in
this wave-vector region shows a reduction in intermittency at the small scales
which can also be explained by the presence of wave activity. Our results
suggest that small-scale turbulence exhibits linear-wave properties of kinetic
Alfv\'en and possibly ion-Bernstein/magnetosonic waves. Based on our results,
we speculate that these waves may play a role in describing the observed
reduction in intermittency at sub ion scales.",2010.12240v1
2003-04-17,Antiferromagnetism and d-wave superconductivity in (doped) Mott insulators: A wave function approach,"We propose a class of wave functions that provide a unified description of
antiferromagnetism and d-wave superconductivity in (doped) Mott insulators. The
wave function has a Jastrow form and prohibits double occupancies. In the
absence of holes, the wave function describes antiferromagnetism accurately.
Off diagonal long range order develops at finite doping and the superconducting
order parameter has d-wave symmetry. We also show how nodal quasiparticles and
neutral spin excitations can be constructed from this wave function.",0304388v2
2003-09-24,Orbital Wave and its Observation in Orbital Ordered Titanates and Vanadates,"We present a theory of the collective orbital excitation termed orbital wave
in perovskite titanates and vanadates with the triply degenerate $t_{2g}$
orbitals. The dispersion relations of the orbital waves for the orbital ordered
LaVO$_3$, YVO$_3$ and YTiO$_3$ are examined in the effective spin-orbital
coupled Hamiltonians associated with the Jahn-Teller type couplings. We propose
possible scattering processes for the Raman and inelastic neutron scatterings
from the orbital wave and calculate the scattering spectra for titanates and
vanadates. It is found that both the excitation spectra and the observation
methods of the orbital wave are distinct qualitatively from those for the $e_g$
orbital ordered systems.",0309538v2
2005-03-14,Surface spin waves in superconducting and insulating ferromagnets,"Surface magnetization waves are studied on a semi-infinite magnetic medium in
the perpendicular geometry. Both superconducting and insulating ferromagnets
are considered. Exchange and dipole energies are taken into account, as well as
retardation effects. At large wave vectors, the spectrum for a superconductor
and insulator is the same, though for the former the branch is terminated much
earlier than for the latter due to excitation of plasmons. At small wave
vectors, the surface wave is more robust in the superconductor since it is
separated from the bulk continuum by a finite gap.",0503340v1
1999-06-07,Gravitational waves and massless particle fields,"These notes address the planar gravitational wave solutions of general
relativity in empty space-time, and analyze the motion of test particles in the
gravitational wave field. Next we consider related solutions of the Einstein
equations for the gravitational field accompanied by long-range wave fields of
scalar, spinor and vector type, corresponding to particles of spin s=(0,1/2,1).
The motion of test masses in the combined gravitational and scalar, spinor or
vector wave fields is discussed.",9906026v2
1993-09-17,Generalized Relativistic Meson Wave Function,"We study the most general, relativistic, constituent $q{\overline q}$ meson
wave function within a new covariant framework. We find that by including a
tensor wave function component, a pure valence quark model is now capable of
reproducing not only all static pion data ($f_\pi$, $\langle r_\pi^2 \rangle$)
but also the distribution amplitude, form factor $(F_\pi(Q^2))$, and structure
functions. Further, our generalized spin wave function provides a much better
detailed description of meson properties than models using a simple
relativistic extension of the $S=L=0$ nonrelativistic wave function.",9309284v1
2020-11-20,Confined magnetoelastic waves in thin waveguides,"The characteristics of confined magnetoelastic waves in nanoscale
ferromagnetic magnetostrictive waveguides have been investigated by a
combination of analytical and numerical calculations. The presence of both
magnetostriction and inverse magnetostriction leads to the coupling between
confined spin waves and elastic Lamb waves. Numerical simulations of the
coupled system have been used to extract the dispersion relations of the
magnetoelastic waves as well as their mode profiles.",2011.10326v1
2021-01-11,Relativistic wave--particle duality for spinors,"We propose that relativistic wave--particle duality can be embodied in a
relation $\langle u^i\rangle=\bar{\psi}\gamma^i\psi/\bar{\psi}\psi$, which
determines the mean four-velocity of the fermion particle associated with a
Dirac wave function. We use the Einstein--Cartan theory of gravity with
torsion, which incorporates the spin-orbit interaction in curved spacetime.
This relation is satisfied by a spinor plane wave and it is consistent with the
energy-momentum tensor for particles. We suggest that spacetime guides the
evolution of a wave function, that in turn guides the mean motion of the
associated particle. Consequently, spacetime guides the motion of particles.
The exact motion is limited by the uncertainty principle.",2101.04212v1
2022-06-13,Searches for Continuous-Wave Gravitational Radiation,"Now that detection of gravitational wave signals from the coalescence of
extra-galactic compact binary star mergers has become nearly routine, it is
intriguing to consider other potential gravitational wave signatures. Here we
examine the prospects for discovery of continuous gravitational waves from
fast-spinning neutron stars in our own galaxy and from more exotic sources.
Potential continuous-wave sources are reviewed, search methodologies and
results presented and prospects for imminent discovery discussed.",2206.06447v2
2023-11-12,$L^p$-boundedness of wave operators for fourth order Schrödinger operators with zero resonances on $\mathbb{R}^3$,"Let $H = \Delta^2 + V$ be the fourth-order Schr\""odinger operator on
$\mathbb{R}^3$ with a real-valued fast-decaying potential $V$. If zero is
neither a resonance nor an eigenvalue of $H$, it has recently been shown by
Goldberg and Green \cite{GoGr21} that the wave operators $W_\pm(H, \Delta^2)$
are bounded on $L^p(\mathbb{R}^3)$ for $1 < p < \infty$. Additionally, it has
been proved by the authors in \cite{MWY23} that these wave operators are
unbounded at the endpoints, i.e., for $p=1$ and $p=\infty$.
  In this paper, our primary focus is to further establish the $L^p$-bounds of
$W_\pm(H, \Delta^2)$ that exhibit all types of singularities at the zero energy
threshold. We first prove that $W_\pm(H, \Delta^2)$ are bounded on
$L^p(\mathbb{R}^3)$ for $1 < p < \infty$ in the first kind resonance case. We
then proceed to establish for the second kind resonance case that they are
bounded on $L^p(\mathbb{R}^3)$ for $1 < p < 3$, but not for $3 \le p < \infty$.
  In the third kind resonance case, we show that $W_\pm(H, \Delta^2)$ are
bounded on $L^p(\mathbb{R}^3)$ for $1<p<3$. Remarkably, we can also prove that
$W_\pm(H, \Delta^2)$ remain bounded on $L^p(\mathbb{R}^3)$ for $3\le p<\infty$
if in addition $H$ has a zero eigenvalue, but no $p$-wave zero resonance and
all zero eigenfunctions are orthogonal to $x_ix_jx_kV$ in $L^2(\mathbb{R}^3)$
for all $i,j,k=1,2,3$ with $x=(x_1,x_2,x_3)$ and that, without such additional
conditions, they are unbounded on $L^p(\mathbb{R}^3)$ for $3\le p<\infty$.
  These results precisely delineate all $L^p$-bounds of the wave operators
$W_\pm(H, \Delta^2)$ in $\mathbb{R}^3$ with the exception of the endpoints
$p=1$ and $p=\infty$. As a result, $L^p$-$L^q$ decay estimates are derived for
solutions of fourth-order Schr\""odinger equations and beam equations with zero
resonance singularities.",2311.06763v1
1998-04-14,Resonant production of gamma rays in jolted cold neutron stars,"Acoustic shock waves passing through colliding cold neutron stars can cause
repetitive superconducting phase transitions in which the proton condensate
relaxes to its equilibrium value via coherent oscillations. As a result, a
resonant non-thermal production of gamma rays in the MeV energy range with
power up to 10^(52) erg/s can take place during the short period of time before
the nuclear matter is heated by the shock waves.",9804134v1
2007-01-04,Solar Resonant Diffusion Waves as a Driver of Terrestrial Climate Change,"A theory is described based on resonant thermal diffusion waves in the sun
that appears to explain many details of the paleotemperature record for the
last 5.3 million years. These include the observed periodicities, the relative
strengths of each observed cycle, and the sudden emergence in time for the 100
thousand year cycle. Other prior work suggesting a link between terrestrial
paleoclimate and solar luminosity variations has not provided any specific
mechanism. The particular mechanism described here has been demonstrated
empirically, although not previously invoked in the solar context. The theory
also lacks most of the problems associated with Milankovitch cycles.",0701117v1
1999-03-10,Effects of resonant tunneling in electromagnetic wave propagation through a polariton gap,"We consider tunneling of electromagnetic waves through a polariton band gap
of a 1-D chain of atoms. We analytically show that a defect embedded in the
structure gives rise to the resonance transmission at the frequency of a local
polariton state associated with the defect. Numerical Monte-Carlo simulations
are used to examine properties of the electromagnetic band arising inside the
polariton gap due to finite concentration of defects.",9903172v1
2000-09-11,First experimental evidence of one-dimensional plasma modes in superconducting thin wires,"We have studied niobium superconducting thin wires deposited onto a
SrTiO$_{3}$ substrate. By measuring the reflection coefficient of the wires,
resonances are observed in the superconducting state in the 130 MHz to 4 GHz
range. They are interpreted as standing wave resonances of one-dimensional
plasma modes propagating along the superconducting wire. The experimental
dispersion law, $\omega$ versus $q$, presents a linear dependence over the
entire wave vector range. The modes are softened as the temperature increases
close the superconducting transition temperature. Very good agreement are
observed between our data and the dispersion relation predicted by Kulik and
Mooij and Sch\""on.",0009146v1
2005-07-14,Modeling of Isotropic Backward-Wave Materials Composed of Resonant Spheres,"A possibility to realize isotropic artificial backward-wave materials is
theoretically analyzed. An improved mixing rule for the effective permittivity
of a composite material consisting of two sets of resonant dielectric spheres
in a homogeneous background is presented. The equations are validated using the
Mie theory and numerical simulations. The effect of a statistical distribution
of sphere sizes on the increasing of losses in the operating frequency band is
discussed and some examples are shown.",0507324v1
2006-05-26,Elastic Light Scattering by Semiconductor Quantum Dots,"Elastic light scattering by low-dimensional semiconductor objects is
investigated theoretically. The differential cross section of resonant light
scattering on excitons in quantum dots is calculated. The polarization and
angular distribution of scattered light do not depend on the quantum-dot form,
sizes and potential configuration if light wave lengths exceed considerably the
quantum-dot size. In this case the magnitude of the total light scattering
cross section does not depend on quantum-dot sizes. The resonant total light
scattering cross section is about a square of light wave length if the exciton
radiative broadening exceeds the nonradiative broadening. Radiative broadenings
are calculated.",0605653v1
1999-05-13,Kinetic description of particle interaction with a gravitational wave,"The interaction of charged particles, moving in a uniform magnetic field,
with a plane-polarized gravitational wave is considered using the
Fokker-Planck- Kolmogorov (FPK) approach. By using a stochasticity criterion,
we determine the exact locations in phase space, where resonance overlapping
occurs. We investigate the diffusion of orbits around each primary resonance of
order (m) by deriving general analytical expressions for an effective diffusion
coeficient. A solution to the corresponding diffusion equation (Fokker-Planck
equation) for the static case is found. Numerical integration of the full
equations of motion and subsequent calculation of the diffusion coefficient
verifies the analytical results.",9905044v1
2005-12-11,Challenges in Signal Analysis of Resonant-Mass Gravitational Wave Detectors,"An overview of the main points related to data analysis in resonant-mass
gravitational wave detectors will be presented. Recent developments on the data
analysis system for the Brazilian detector SCHENBERG will be emphasized.",0512063v1
2006-08-23,On the Sensitivity of a Hollow Sphere as a Multi-modal Resonant Gravitational Wave Detector,"We present a numerical analysis to simulate the response of a spherical
resonant gravitational wave detector and to compute its sensitivity. Under the
assump- tion of optimal filtering, we work out the sensitivity curve for a
sphere first taking into account only a single transducer, and then using a
coherent analysis of the whole set of transducers.",0608106v2
1999-05-01,Natural parity resonances in the etha pi+ pi- and omega omega,"Results of the ethapi+pi- and omegaomega final state partial wave
analysis(PWA) are presented. The mass-independent and the mass-dependent PWA
were performed. The ethapi+pi- system PWA results in the observation of the
resonances in the JPC=1--,3--,2++ and 4++ waves. The results of the omegaomega
system PWA confirms the existence of the f2(1565) and f4(2050). The f2(1950) is
observed. There is evidence for a f4(2300) meson.",9905001v1
2001-01-05,Instabilities in neutrino-plasma density waves,"One examines the interaction and possible resonances between supernova
neutrinos and electron plasma waves. The neutrino phase space distribution and
its boundary regions are analyzed in detail. It is shown that the boundary
regions are too wide to produce non-linear resonant effects. The growth or
damping rates induced by neutrinos are always proportional to the neutrino flux
and $G_{{\rm F}}^{2}$.",0101054v2
2004-12-21,A Rich Example of Geometrically Induced Nonlinearity: From Rotobreathers and Kinks to Moving Localized Modes and Resonant Energy Transfer,"We present an experimentally realizable, simple mechanical system with linear
interactions whose geometric nature leads to nontrivial, nonlinear dynamical
equations. The equations of motion are derived and their ground state
structures are analyzed. Selective ``static'' features of the model are
examined in the context of nonlinear waves including rotobreathers and
kink-like solitary waves. We also explore ``dynamic'' features of the model
concerning the resonant transfer of energy and the role of moving intrinsic
localized modes in the process.",0412051v1
2006-04-06,A reduction of the resonant three-wave interaction to the generic sixth Painleve' equation,"Among the reductions of the resonant three-wave interaction system to
six-dimensional differential systems, one of them has been specifically
mentioned as being linked to the generic sixth Painleve' equation P6. We derive
this link explicitly, and we establish the connection to a three-degree of
freedom Hamiltonian previously considered for P6.",0604011v1
2003-06-20,Negative Parity N* Resonances in an Extended GBE,"In this paper, we calculate the masses and mixing angles of L=1 negative
parity N* resonances in an extended GBE (Goldstone-boson-exchange model) with
harmonic-oscillator wave functions. By using those mixing angles, we get their
photoproduction amplitudes, and compare them with experimental data and the
results of OPE (one-pion-exchange model), OPsE (only pseudoscalar meson
exchange model), and OGE (one-gluon-exchange model). We find that the extended
GBE gives right internal wave functions. It is essential to extend GBE to
include not only pseudoscalar meson exchanges but also vector meson exchanges.",0306055v1
2006-08-30,Phenomenological hadron form factors: shape and relativity,"The use of relativistic quark models with simple parametric wave functions
for the understanding of the electromagnetic structure of nucleons together
with their electromagnetic transition to resonances is discussed. The
implications of relativity in the different ways it can be implemented in a
simple model are studied together with the role played by mixed symmetry
s-state and D-state deformations of the rest frame wave functions of the
nucleon and Delta resonance.",0608076v1
1998-08-19,Diffractive effects in singly-resonant continuous-wave parametric oscillators,"This paper presents a detailed numerical study of the effect of focusing on
the conversion efficiency of low-loss singly-resonant parametric oscillators
with collinear focusing of pump and signal. Results are given for the maximal
pump depletion and for pump power levels required for various amounts of
depletion, as functions of pump and signal confocal parameters, for kI/kP=0.33
and 0.50. It is found that the ratio of pump depletion to maximal depletion as
a function of the ratio of pump power to threshold power agrees with the
plane-wave prediction to within 5%, for a wide range of focusing conditions.
The observed trends are explained as resulting from intensity and phase
dependent mechanisms.",9808026v1
2000-04-11,Theory of acoustic analog of magneto-optic Kerr effect under magnon-phonon resonance,"Theory of the acoustic analog of the polar Kerr effect is developed for an
inclined incidence of the p-type wave on the interface between isotropic
non-magnetic medium and ferromagnetic cubic crystal. Magnetic field dependences
of ellipticity and rotation of the polarization plane of the reflected wave
under magnon-phonon resonance are analysed in a weak-coupling approximation for
interaction of magnetic and elastic subsystems.",0004017v1
2002-11-07,"Advanced configuration of gravitational-wave interferometer on the base of ""sensitive mode"" in ""white-light cavity""","A novel conception of ""sensitive mode"" (SM) is proposed to apply in
gravitational-wave advanced interferometer configuration. The SM is resonant
oscillation of electromagnetic field in ""white-light cavity"", where the
resonance line is broadened without decreasing cavity quality. The frequency of
the SM is greatly susceptible to the change of cavity length, and the SM is
established in a cavity with time constant smaller than a conventional mode.
Due to these advantages the sensitivity and bandwidth of AIC can be increased.",0211032v1
2003-01-31,Bessel-Gauss beam optical resonator,"In a simple picture, a Bessel beam is viewed as a transverse standing wave
formed in the interference region between incoming and outgoing conical waves.
Based on this interpretation we propose an optical resonator that supports
modes that are approximations to Bessel-Gauss beams. The Fox-Li algorithm in
two transverse dimension is applied to confirm the conlcusion",0301082v2
2003-05-12,Local Solutions for Generic Multidimensional Resonant Wave Conversion,"In more than one spatial dimension, resonant linear conversion from one wave
type to another can have a more complex geometry than the familiar 'avoided
crossing' of one-dimensional problems. In previous work we have shown that
helical ray shapes are generic in a mathematical sense. Here we briefly
describe how the local field structure can be computed.",0305047v1
2004-08-31,Resonant modes in triangular dielectric cavities,"The resonant optical modes of a high permittivity dielectric prism with an
equilateral triangular cross section are discussed. Eigenmode solutions of the
scalar Helmholtz equation with Dirichlet boundary conditions, appropriate to a
conducting boundary, are applied for this purpose. The particular plane wave
components present in these modes are analyzed for their total internal
reflection behavior and implied mode confinement when the conducting boundary
is replaced by a sharp dielectric mismatch. Improvement in TIR confinement by
adjusting the longitudinal wavevector $k_z$ is also discussed. For
two-dimensional electromagnetic solutions ($k_z=0$), TE polarization leads to
longer lifetime than TM polarization, assuming that escape of evanescent
boundary waves at the corners is the primary decay process.",0409002v1
2004-09-24,"First observation of generation in the backward wave oscillator with a ""grid"" diffraction grating and lasing of the volume FEL with a ""grid"" volume resonator","First observation of generation in the backward wave oscillator with a ""grid""
diffraction grating and lasing of the volume FEL with a ""grid"" volume resonator
that is formed by a perodic set of metallic threads inside a rectangular
waveguide is considered.",0409125v1
2007-06-04,Decay and non-decay of the local energy for the wave equation in the De Sitter - Schwarzschild metric,"We describe an expansion of the solution of the wave equation in the De
Sitter - Schwarzschild metric in terms of resonances. The main term in the
expansion is due to a zero resonance. The error term decays polynomially if we
permit a logarithmic derivative loss in the angular directions and
exponentially if we permit an small derivative loss in the angular directions.",0706.0350v1
2007-07-03,Detuned Twin-Signal-Recycling for ultra-high precision interferometers,"We propose a new interferometer technique for high precision phase
measurements such as those in gravitational wave detection. The technique
utilizes a pair of optically coupled resonators that provides identical
resonance conditions for the upper as well the lower phase modulation signal
sidebands. This symmetry significantly reduces the noise spectral density in a
wide frequency band compared with single sideband recycling topologies of
current and planned gravitational wave detectors. Furthermore the application
of squeezed states of light becomes less demanding.",0707.0413v1
2007-08-09,Polariton amplification in a multiple-quantum-well resonant photonic crystal,"Based on a microscopic many-particle theory we study the amplification of
polaritons in a multiple-quantum-well resonant photonic crystal. For the
Bragg-spaced multiple quantum wells under investigation we predict that in a
typical pump-probe setup four-wave mixing processes can lead to an unstable
energy transfer from the pump into the probe and the background-free four-wave
mixing directions. We find that under certain excitation conditions this
phase-conjugate oscillation induced instability can lead to a large
amplification of the weak probe pulse.",0708.1300v1
2008-07-09,Resonance-like Goss-Haenchen Shift induced by nano-metal films,"The influence of nano-metal films on the Goos-Haenchen shift (GHS) is
investigated. The films deposited at the total reflecting surface of a perspex
prism/air have a sheet resistance varying between Z = 25 and 3 000 Ohm. A
resonance-like enhancement of the shift and of the absorption is found for TE
polarized waves, when the sheet resistance approaches the value of the vacuum
impedance. For TM waves the influence of the metal films on the GHS is
comparatively weak. The experiments are carried out with microwaves. Keywords:
Goos-Haenchen shift; nano-metallic films, microwaves PACS: 42.25.Bs, 42.25.Gy,
42.50.-p, 73.40.Gk",0807.1537v1
2008-07-15,alpha particle momentum distributions from 12C decaying resonances,"The computed $\alpha$ particle momentum distributions from the decay of
low-lying $^{12}$C resonances are shown. The wave function of the decaying
fragments is computed by means of the complex scaled hyperspherical adiabatic
expansion method. The large-distance part of the wave functions is crucial and
has to be accurately calculated. We discuss energy distributions, angular
distributions and Dalitz plots for the $4^+$, $1^+$ and $4^-$ states of
$^{12}$C.",0807.2375v1
2009-07-20,Qubit-oscillator dynamics in the dispersive regime: analytical theory beyond rotating-wave approximation,"We generalize the dispersive theory of the Jaynes-Cummings model beyond the
frequently employed rotating-wave approximation (RWA) in the coupling between
the two-level system and the resonator. For a detuning sufficiently larger than
the qubit-oscillator coupling, we diagonalize the non-RWA Hamiltonian and
discuss the differences to the known RWA results. Our results extend the regime
in which dispersive qubit readout is possible. If several qubits are coupled to
one resonator, an effective qubit-qubit interaction of Ising type emerges,
whereas RWA leads to isotropic interaction. This impacts on the entanglement
characteristics of the qubits.",0907.3516v1
2009-08-03,Opto-mechanics with surface acoustic wave whispering gallery modes,"A surface acoustic wave (SAW) creates its own high-Q ultra-small volume
whispering gallery modes (WGMs), different from usual bulk acoustic WGMs, in an
optical dielectric WGM resonator. We show that it is possible to realize an
externally controllable, efficient triply-resonant opto-mechanical interaction
between two optical WGMs and the SAW WGM and to use such an interaction in
various sensor applications.",0908.0306v1
2009-11-01,Above-Barrier Reflection of Cold Atoms by Resonant Laser Light within the Gross-Pitaevskii Approximation,"Above-barrier reflection of cold alkali atoms by resonant laser light was
considered analytically within the Gross-Pitaevskii approximation. Correction
for the reflection coefficient because of a weak nonlinearity of the stationary
Schroedinger equation has been derived using multiscale analysis as a form of
perturbation theory. The nonlinearity adds spatial harmonics to linear incident
and reflecting waves. It was shown that the role of nonlinearity increases when
the kinetic energy of an atom is nearly to the height of the potential barrier.
Results are compared to the known numerical derivations for wave functions of
the Gross-Pitaevskii equation with the step potential.",0911.0156v1
2009-12-15,Resonant trapping in the transport of a matter-wave soliton through a quantum well,"We theoretically investigate the scattering of bright solitons in a
Bose-Einstein condensate on narrow attractive potential wells. Reflection,
transmission and trapping of an incident soliton are predicted to occur with
remarkably abrupt transitions upon varying the potential depth. Numerical
simulations of the nonlinear Schroedinger equation are complemented by a
variational collective coordinate approach. The mechanism for nonlinear
trapping is found to rely both on resonant interaction between the soliton and
bound states in the potential well as well as radiation of small amplitude
waves. These results suggest that solitons can be used to probe bound states
that are not accessible through scattering with single atoms.",0912.3019v1
2010-01-02,Triply-resonant Optical Parametric Oscillator by Four-wave Mixing with Rubidium Vapor inside an Optical Cavity,"We present an experimental demonstration of simultaneous above-threshold
oscillations of the Stokes and anti-Stokes fields together with the single
pumping beam with rubidium atoms inside an optical standing-wave cavity. The
triple resonant conditions can be achieved easily by making use of the large
dispersions due to two-photon transitions in the three-level atomic system.
This work provides a way to achieve high efficient nonlinear frequency
conversion and the generated bright Stokes and anti-Stokes cavity output beams
are potential resource for applications in quantum information science.",1001.0291v1
2010-03-02,Resonance Scattering of Waves in Chaotic Systems,"This is a brief overview of RMT applications to quantum or wave chaotic
resonance scattering, focusing mainly on theoretical results obtained via
non-perturbative methods starting from mid-nineties.",1003.0702v1
2010-03-23,Direct observation of mode-coupling instability in two-dimensional plasma crystals,"Dedicated experiments on melting of 2D plasma crystals were carried out. The
melting was always accompanied by spontaneous growth of the particle kinetic
energy, suggesting a universal plasma-driven mechanism underlying the process.
By measuring three principal dust-lattice (DL) wave modes simultaneously, it is
unambiguously demonstrated that the melting occurs due to the resonance
coupling between two of the DL modes. The variation of the wave modes with the
experimental conditions, including the emergence of the resonant (hybrid)
branch, reveals exceptionally good agreement with the theory of mode-coupling
instability.",1003.4479v1
2010-04-03,Dynamics of point Josephson junctions in a microstrip line,"We analyze a new long wave model describing the electrodynamics of an array
of point Josephson junctions in a superconducting cavity. It consists in a wave
equation with Dirac delta function sine nonlinearities. We introduce an adapted
spectral problem whose spectrum gives the resonances in the current-voltage
characteristic curve of any array. Using the associated inner product and
eigenmodes, we establish that at the resonances the solution is described by
two simple ordinary differential equations.",1004.0409v1
2010-05-06,Local diffusion theory of localized waves in open media,"We report a first-principles study of static transport of localized waves in
quasi-one-dimensional open media. We found that such transport, dominated by
disorder-induced resonant transmissions, displays novel diffusive behavior. Our
analytical predictions are entirely confirmed by numerical simulations. We
showed that the prevailing self-consistent localization theory [van Tiggelen,
{\it et. al.}, Phys. Rev. Lett. \textbf{84}, 4333 (2000)] is valid only if
disorder-induced resonant transmissions are negligible. Our findings open a new
direction in the study of Anderson localization in open media.",1005.0951v2
2010-12-15,"Nonlinear Bloch modes, optical switching and Bragg solitons in tightly coupled micro-ring resonator chains","We study nonlinear wave phenomena in coupled ring resonator optical
waveguides in the tight coupling regime. A discrete model for the system
dynamics is put forward and its steady state nonlinear Bloch modes are derived.
The switching behavior of the transmission system is addressed numerically and
the results are explained in the light of this analytical result. We also
present a numerical study on the spontaneous generation of Bragg solitons from
a continuous-wave input.",1012.3286v2
2011-06-02,Self-injection-locked magnetron as an active ring resonator side coupled to a waveguide with a delayed feedback loop,"The theoretical analysis and numerical simulations of the magnetron operation
with a feedback loop were performed assuming that the delay of the
electromagnetic wave propagating in the loop is constant whereas the phase of
the complex feedback reflection coefficient is varied. Results of simulations
showed that by a proper adjustment of values of the time delay and phase of
reflection coefficient that determines phase matching between the waves in the
resonator and feedback loop, one can increase the magnetron's output power
significantly without any other additional measures.",1106.0389v1
2011-11-14,Impedance of the free surface of liquid electrolytes,"A possibility for the observation of so-called structure resonances (SR) in
electrolytes arising due to relative motion of the cluster charged nucleus and
its solvation shell is demonstrated. The discussed method considers the
resonant contribution of the SR to the frequency dependence of the reflection
(transmission) coefficient of the electromagnetic wave interacting with the
free electrolyte surface. Of special interest is the observation of SR for
multiply charged particles in electrolyte providing direct information on the
charge of single cluster. Also important are other not so prominent details of
the wave interaction with mobile charged clusters in electrolyte related to the
formation and complicated nature of the frequency dependence of the charged
cluster associated mass.",1111.3318v1
2011-12-12,Resonance in a driven two-level system: analytical results without the rotating wave approximation,"We consider the problem of two-level system dynamics induced by the
time-dependent field B={a(t)cos\omega t,a(t)sin\omega t,\omega_0}, with a(t)
\sim cn(\nu t,k). The problem is exactly analytically solvable and we propose
the scheme for constructing the solutions. For all field configurations the
resonance conditions are discussed. The explicit solutions for N=1,2 we
obtained coincide at \omega=0 in the proper parameter domain with predictions
of the rotating wave approximation and agree nicely with numerical calculations
beyond it.",1112.2564v1
2012-06-15,Tunable graphene-based polarizer,"It is shown that an attenuated total reflection structure containing a
graphene layer can operate as a tunable polarizer of the electromagnetic
radiation. The polarization angle is controlled by adjusting the voltage
applied to graphene via external gate. The mechanism is based on the resonant
coupling of $p-$polarized electromagnetic waves to the surface
plasmon-polaritons in graphene. The presented calculations show that, at
resonance, the reflected wave is almost 100% $s-$polarized.",1206.3592v1
2013-06-04,Metamaterial Loadings for Waveguide Miniaturization,"We show that a rectangular metallic waveguide loaded with metamaterial
elements consisting of electric-field coupled (ELC) resonators placed at the
side walls can operate well below the cutoff frequency of the respective
unloaded waveguide. The dispersion diagrams indicate that propagating modes in
ELC-loaded waveguides are of forward-type for both TE and TM modes. We also
study the dispersion diagram and transmission characteristics of rectangular
metallic waveguides simultaneously loaded with ELCs and split ring resonators
(SRRs). Such doubly-loaded waveguides can support both forward wave and
backward waves, and provide independent control of the propagation
characteristics for the respective modes.",1306.0928v1
2013-07-25,Optical frequency comb generation from aluminum nitride micro-ring resonator,"Aluminum nitride is an appealing nonlinear optical material for on-chip
wavelength conversion. Here we report optical frequency comb generation from
high quality factor aluminum nitride micro-ring resonators integrated on
silicon substrates. By engineering the waveguide structure to achieve near-zero
dispersion at telecommunication wavelengths and optimizing the phase matching
for four-wave mixing, frequency combs are generated with a single wavelength
continuous-wave pump laser. The Kerr coefficient (n2) of aluminum nitride is
further extracted from our experimental results.",1307.6761v1
2013-08-10,Dipole-induced localized plasmon modes and resonant surface plasmon scattering,"A metal film supports the continuum of propagating surface plasmon waves. The
interaction of these waves with a dipole (nanoparticle) positioned some
distance from the surface of the film can produce well defined localized
plasmon modes whose frequency nonetheless resides inside the continuum. This
leads to the resonant enhancement of scattering of surface plasmons off the
dipole. The maximum of scattering is found to occur when the distance from the
dipole to the surface of the film is equal to one half of the film thickness.
The possibility of controllable plasmon scattering could be advantageous for
the field of nanoplasmonics.",1308.2339v2
2014-01-07,Switching Reciprocity On and Off in a Magneto-Optical X-Ray Scattering Experiment Using Nuclear Resonance of 57Fe Foils,"Reciprocity is when the scattering amplitude of wave propagation satisfies a
symmetry property, connecting a scattering process with an appropriate reversed
one. We report on an experiment using nuclear resonance scattering of
synchrotron radiation, which demonstrates that magneto-optical materials do not
necessarily violate reciprocity. The setting enables to switch easily between
reciprocity and its violation. In the latter case, the exhibited reciprocity
violation is orders of magnitude larger than achieved by previous wave
scattering experiments.",1401.1348v1
2014-03-30,Evidence of giant oscillator strength in the exciton dephasing of CdSe nanoplatelets measured by resonant four-wave mixing,"We measured the intrinsic ground-state exciton dephasing and population
dynamics in colloidal quasi two-dimensional (2D) CdSe nanoplatelets at low
temperature (5-50K) using transient resonant four-wave mixing in heterodyne
detection. Our results indicate that below 20K the exciton dephasing is
lifetime limited, with the exciton population lifetime being as fast as 1ps.
This is consistent with an exciton lifetime given by a fast radiative decay due
to the large in-plane coherence area of the exciton center-of-mass motion in
these quasi 2D systems compared to spherical nanocrystals.",1403.7798v1
2015-02-20,Spontaneous four-wave mixing in lossy microring resonators,"We develop a general Hamiltonian treatement of spontaneous four-wave mixing
in a microring resonator side-coupled to a channel waveguide. The effect of
scattering losses in the ring is included, as well as parasitic nonlinear
effects including self- and cross-phase modulation. A procedure for computing
the output of such a system for arbitrary parameters and pump states is
presented. For the limit of weak pumping an expression for the joint spectral
intensity of generated photon pairs, as well as the singles-to-coincidences
ratio, is derived.",1502.05900v2
2015-04-02,Steering in-plane shear waves with inertial resonators in platonic crystals,"Numerical simulations shed light on control of shear elastic wave propagation
in plates structured with inertial resonators. The structural element is
composed of a heavy core connected to the main freestanding plate through tiny
ligaments. It is shown that such a configuration exhibits a complete band gap
in the low frequency regime. As a byproduct, we further describe the asymmetric
twisting vibration of a single scatterer via modal analysis, dispersion and
transmission loss. This might pave the way to new functionalities such as
focusing and self-collimation in elastic plates.",1504.00487v1
2015-04-20,Nonlinear sub-cyclotron resonance as a formation mechanism for gaps in banded chorus,"An interesting characteristic of magnetospheric chorus is the presence of a
frequency gap at $\omega \simeq 0.5\Omega_e$, where $\Omega_e$ is the electron
cyclotron angular frequency. Recent chorus observations sometimes show
additional gaps near $0.3\Omega_e$ and $0.6\Omega_e$. Here we present a novel
nonlinear mechanism for the formation of these gaps using Hamiltonian theory
and test-particle simulations in a homogeneous, magnetized, collisionless
plasma. We find that an oblique whistler wave with frequency at a fraction of
the electron cyclotron frequency can resonate with electrons, leading to
effective energy exchange between the wave and particles.",1504.05243v1
2016-02-12,Triply-resonant Continuous Wave Parametric Source with a Microwatt Pump,"We demonstrate a nanophotonic parametric light source with a record high
normalized conversion efficiency of $3\times 10^6\, W^{-2}$, owing to
resonantly enhanced four wave mixing in coupled high-Q photonic crystal
resonators. The rate of spontaneously emitted photons reaches 14 MHz.",1602.04833v1
2016-02-18,Emulation of Fabry-Perot and Bragg resonators with temporal optical solitons,"The scattering of weak dispersive waves (DW) on several equally spaced
temporal solitons is studied. It is shown by systematic numerical simulations
that the reflection of the DWs from the soliton trains strongly depends on the
distance between the solitons. The dependence of the reflection and
transmission coefficients on the inter-soliton distance and the frequency of
the incident waves is studied in detail, revealing fascinating quasi-periodic
behavior. The analogy between the observed nonlinear phenomena in temporal
domain and usual Fabry-Perot and Bragg resonators is discussed.",1602.05896v1
2016-04-11,Design study of a beta=0.09 high current superconducting half wave resonator,"There's presently a growing demand for high current proton and deuteron
linear accelerators based on superconducting technology to better support
various fields of science. A \b{eta}=0.09 162.5 MHz high current
superconducting half wave resonator (HWR) has been designed at Peking
University to accelerate 100 mA proton beam or 50 mA deuteron beam after the
RFQ accelerating structure. The detailed electromagnetic design, multipacting
simulation, mechanical analysis of the cavity will be given in this paper.",1604.02799v1
2016-07-26,Ultra-high Q Acoustic Resonance in Superfluid 4He,"We report the measurement of the acoustic quality factor of a gram-scale,
kilo-hertz frequency superfluid resonator, detected through the parametric
coupling to a superconducting niobium microwave cavity. For temperature between
400mK and 50mK, we observe a $T^{-4}$ temperature dependence of the quality
factor, consistent with a 3-phonon dissipation mechanism. We observe Q factors
up to $1.4\cdot10^8$, consistent with the dissipation due to dilute $^3$He
impurities, and expect that significant further improvements are possible.
These experiments are relevant to exploring quantum behavior and decoherence of
massive macroscopic objects, the laboratory detection of continuous wave
gravitational waves from pulsars, and the probing of possible limits to
physical length scales.",1607.07902v1
2017-08-24,Excitation of coupled phononic frequency combs via two-mode parametric three-wave mixing,"This paper builds on the recent demonstration of three-wave mixing based
phononic frequency comb. Here, in this process, an intrinsic coupling between
the drive and resonant frequency leads to a frequency comb of spacing
corresponding to the separation between drive and resonant frequency. Now, in
this paper, we experimentally demonstrate the possibility to further excite
multiple frequency combs with the same external drive through its coupling with
other identical devices. In addition, we also experimentally identify
interesting features associated with such a frequency comb generation process.",1708.07563v2
2017-11-13,Ultra-low power nonlinear optics in a high Q CMOS compatible integrated micro-ring resonator,"We demonstrate efficient, low power, continuous-wave four-wave mixing in the
C-band, using a high index doped silica glass micro ring resonator having a
Q-factor of 1.2 million. A record high conversion efficiency for this kind of
device is achieved over a bandwidth of 20nm. We show theoretically that the
characteristic low dispersion enables phase-matching over a bandwidth > 160nm.",1711.04400v1
2017-11-13,"JOZSO, a renewed version of the computer code GAMOW for calculating broad neutron resonances in phenomenological nuclear potentials","A renewed version of the computer code GAMOW ~\cite{[Ve82]} is given in which
the difficulties in calculating broad neutron resonances are amended. New types
of phenomenological neutron potentials with strict finite range are built in.
Landscape of the S-matrix can be generated on a given domain of the complex
wave number plane and S-matrix poles in the domain are localized. Normalized
Gamow wave functions and trajectories of given poles can be calculated
optionally.",1711.04619v2
2017-11-29,Tailored Raman-resonant four-wave-mixing process,"Nonlinear optical processes are strongly dominated by phase relationships
among electromagnetic fields that are relevant to its optical process. In this
paper, we theoretically and experimentally show, as a typical example, that in
a Raman-resonant four-wave-mixing process, the first anti-Stokes and Stokes
generations can be tailored to a variety of forms by manipulating the phase
relationships among the relevant electromagnetic fields.",1711.10772v1
2018-01-08,Radiation of Channeled Positrons in Ultrasonic Wave,"In the classical approximation, we examine the problem of radiation by
channeled positrons in the field of a longitudinal ultrasonic wave when the
condition of parametric resonance is satisfied. We show that in the case of
planar channeling the intensity of the spectral distribution of the radiation
can be several times larger than when the resonance condition is not satisfied.",1801.10222v2
2018-03-15,Lineshape-asymmetry elimination in weak atomic transitions driven by an intense standing wave field,"Owing to the ac-Stark effect, the lineshape of a weak optical transition in
an atomic beam can become significantly distorted, when driven by an intense
standing wave field. We use an Yb atomic beam to study the lineshape of the 6s2
1S0 -> 5d6s 3D1 transition, which is excited with light circulating in a
Fabry-Perot resonator. We demonstrate two methods to avoid the distortion of
the transition profile. Of these, one relies on the operation of the resonator
in multiple longitudinal modes, and the other in multiple transverse modes.",1803.05884v2
2018-06-21,Stability of Periodic Travelling Wave Solutions to the Kawahara Equation,"We analyse the stability of periodic, travelling-wave solutions to the
Kawahara equation and some of its generalizations. We determine the parameter
regime for which these solutions can exhibit resonance. By examining
perturbations of small-amplitude solutions, we show that generalised resonance
is a mechanism for high-frequency instabilities. We derive a quadratic equation
which fully determines the stability region for these solutions. Focussing on
perturbations of the small-amplitude solutions, we obtain asymptotic results
for how their instabilities develop and grow. Numerical computation is used to
confirm these asymptotic results and illustrate regimes where our asymptotic
analysis does not apply.",1806.08445v1
2017-05-24,Influence of optical nonlinearities on plasma waves in graphene,"A theory of the nonlinear plasma waves in graphene is developed in the
nonperturbative regime. The influence of strong electric fields on the position
and linewidth of plasma resonances in the far-infrared transmission
experiments, as well as on the wavelength and the propagation length in the
scanning near-field optical microscopy experiments is studied. The theory shows
that the fields of order of a few to a few tens of kV/cm should lead to a red
shift and broadening of plasma resonances in the first type and to a reduction
of the wavelength and the propagation length in the second type of experiments.",1705.08999v2
2012-09-19,Continuous-wave backward frequency doubling in periodically poled lithium niobate,"We report on backward second-harmonic-generation in bulk periodically poled
congruent lithium niobate with a 3.2 microns period. A tunable continuous-wave
Ti:sapphire laser allowed us exciting two resonant quasi-phase-matching orders
in the backward configuration. The resonances were also resolved by temperature
tuning and interpolated with standard theory to extract relevant information on
the sample.",1209.4288v1
2014-06-09,Resonantly phase-matched Josephson junction traveling wave parametric amplifier,"We develop a technique to overcome phase-mismatch in Josephson-junction
traveling wave parametric amplifiers in order to achieve high gain over a broad
bandwidth. Using ""resonant phase matching,"" we design a compact superconducting
device consisting of a transmission line with subwavelength resonant inclusions
that simultaneously achieves a gain of 20 dB, an instantaneous bandwidth of 3
GHz, and a saturation power of -98 dBm. Such an amplifier is well-suited to
cryogenic broadband microwave measurements such as the multiplexed readout of
quantum coherent circuits based on superconducting, semiconducting, or
nano-mechanical elements as well as traditional astronomical detectors.",1406.2346v1
2019-02-04,Metasurfaces with Interleaved Electric and Magnetic Resonances for Broadband Arbitrary Group Delay in Reflection,"Metasurfaces impart phase discontinuities on impinging electromagnetic waves
that are typically limited to 0-2$\pi$. Here, we show that they can break free
from this limitation and supply arbitrarily-large phase modulation over
ultra-wide bandwidths. This is achieved by implementing multiple,
properly-arranged resonances in the electric and magnetic sheet admittivities.
We demonstrate metasurfaces that can perfectly reflect a broadband pulse
imparting a prescribed group delay without distorting the pulse shape, opening
new possibilities for temporal control and dispersion engineering across deeply
subwavelength physical scales.",1902.01121v1
2016-03-02,Amplitude analysis of $\bar{K}N$ scattering,"We present the results of a coupled-channel model for $\bar{K}N$ scattering
in the resonance region. The model fulfills unitarity, has the correct
analytical properties for the amplitudes and the partial waves have the right
threshold behavior. The parameters of the model have been established by
fitting single-energy partial waves up to $J=7/2$ and up to 2.15 GeV of
center-of-mass energy. The $\Lambda^*$ and $\Sigma^*$ spectra has been
obtained, providing a comprehensive picture of the $S=-1$ hyperon spectrum. We
use the structure of the hyperon spectrum and Regge phenomenology to gain
insight on the nature of the $\Lambda(1405)$ resonances.",1603.00868v1
2016-03-04,Optical realization of the dissipative quantum oscillator,"An optical realization of the damped quantum oscillator, based on transverse
light dynamics in an optical resonator with slowly-moving mirrors, is
theoretically suggested. The optical resonator setting provides a simple
implementation of the time-dependent Caldirola-Kanai Hamiltonian of the
dissipative quantum oscillator, and enables to visualize the effects of damped
oscillations in the classical (ray optics) limit and wave packet collapse in
the quantum (wave optics) regime.",1603.01364v1
2016-03-18,Modeling of Self-Pumped Singly Resonant Optical Parametric Oscillator,"A model of the steady-state operating, self-pumped singly resonant optical
parametric oscillator (SPSRO) has been developed. The characteristics of quasi
three-level laser gain medium pumped longitudinally have been taken into
account. The characteristics of standing wave cavity, reabsorption losses,
focusing Gaussian beams of the pump laser, fundamental laser and signal wave
have been considered in the analyses. Furthermore, The power characteristics of
threshold and efficiency have been analyzed, employing a Yb3+-doped
periodically poled lithium niobate co-doped with MgO (Yb3+:MgO:PPLN) as the
medium of laser gain and second-order nonlinear crystal.",1603.05840v1
2016-12-12,Spontaneous emission in a quantum system driven by the resonant field beyond the rotating wave approximation,"Quasi-stationary states of the quantum system in the driving resonant field
are considered without rotating wave approximation. Conditions under which the
spontaneous emission could be suppressed in this system are investigated in the
special case when the frequency of the driving field is essentially less than
the frequency of spontaneous emission. It is shown that the characteristic
parameters of the effect are substantially changed in comparison with the
results corresponding to RWA. The real physical system for which the considered
effects could be observed is described.",1612.03688v1
2017-02-09,A waveguide cavity resonator source of squeezing,"We present the generation of continuous-wave optical squeezing from a
titanium-indiffused lithium niobate waveguide resonator. We directly measure
2.9\pm 0.1 dB of single-mode squeezing, which equates to a produced level of
4.9\pm 0.1 dB after accounting for detection losses. This device showcases the
current capabilities of this waveguide architecture and precipitates more
complicated integrated continuous-wave quantum devices in the
continuous-variable regime.",1702.02855v1
2019-03-14,Scattering for the quadratic nonlinear Schrödinger system in $\mathbb{R}^5$ without mass-resonance condition,"We consider the quadratic nonlinear Schr\""{o}dinger system (NLS system)
\begin{align*}\begin{cases} i\partial_t u + \Delta u = v \overline{u}, \\
i\partial_t v+\kappa \Delta v = u^2, \end{cases} \text{ on } I \times
\mathbb{R}^5, \end{align*} where $\kappa>0$. The scattering below the standing
wave solutions for NLS system was obtained by the first author when $\kappa =
1/2$. The condition of $\kappa=1/2$ is called mass-resonance. In this paper, we
prove scattering below the standing wave solutions when $\kappa \neq 1/2$ under
the radially symmetric assumption. Our proof is based on the concentration
compactness and the rigidity by Kenig--Merle. Moreover, we discuss the
concentration compactness and the rigidity for non-radial solutions.",1903.05880v1
2019-05-25,Generating frequency-bin qubits via spontaneous four-wave mixing in a photonic molecule,"A scheme for heralded generation of frequency-bin photonic qubits via
spontaneous four-wave mixing in a system of coupled microring resonators
(photonic molecule) is developed so that the qubit state is fully controlled by
the frequency amplitude of the pump field. It is shown that coupling parameters
of the photonic molecule can be optimized to provide generation of nearly pure
heralded photons. The heralded qubit state does not depend on the microring
resonator mode frequency, thereby allowing to take advantage of frequency
multiplexing for improving efficiency of quantum information processing.",1905.10571v2
2020-03-01,Parametric study of the seismic response of a hill or mountain,"The problem of the response of a cylindrical protuberance of rectangular
shape to a SH seismic plane wave is studied in parametric manner so as to
provide answers to the questions: (i) where and how should one measure this
response, (ii) is the normal-incidence response a valid indication of response
at other incident angles of the seismic plane wave, iii) is it possible to
predict the maximal response without a detailed knowledge of the subsurface
composition, iv) how does the aspect ratio of the protuberance affect the
resonant response, and v) is the resonant wavefield uniformly distributed in
the interior of the protuberance?",2003.00461v1
2020-11-06,Scalar Differential Equations of Thin Film Bulk Acoustic Wave Resonators with Surface Acoustic Impedance for Sensor Application,"We generalize the two-dimensional scalar differential equations for the
thickness-extensional operating modes of thin film bulk acoustic wave
resonators (FBARs) to include the effects of surface impedance so that the
equations can be used to model sensors based on FBARs. A mass sensor is
analyzed as an example to show the effectiveness of the equations obtained. The
mass layer inducer frequency shifts are calculated. It is also found that the
vibration may be confined under the driving electrode or the mass layer. These
are fundamental to mass sensor design.",2011.03251v1
2019-07-30,Electromagnetic Grazing Anomaly: Energy Flux Resonance Behaviour and Brewster Angle Analogy,"The diffraction of electromagnetic waves at the surface periodic structures
accompanied by strong anomalous effects in different diffraction orders is
considered in great detail for high-contrast interfaces. We restrict our
discussion to the TM polarization of the incident wave (the magnetic field is
orthogonal to the plane of incidence) and the simplest geometry when the plane
of incidence is orthogonal to the grating grooves. The most attention is
focused on the strong maxima and minima of the energy flux density accompanying
specific grazing propagation of some diffraction order. Relation to other
anomalies, both Rayleigh and the resonance ones is discussed as well.",1907.13015v1
2019-10-02,"Resolvent estimates, wave decay, and resonance-free regions for star-shaped waveguides","Using coordinates $(x,y)\in \mathbb R\times \mathbb R^{d-1}$, we introduce
the notion that an unbounded domain in $\mathbb R^d$ is star shaped with
respect to $x=\pm \infty$. For such domains, we prove estimates on the
resolvent of the Dirichlet Laplacian near the continuous spectrum. When the
domain has infinite cylindrical ends, this has consequences for wave decay and
resonance-free regions. Our results also cover examples beyond the star-shaped
case, including scattering by a strictly convex obstacle inside a straight
planar waveguide.",1910.01038v2
2020-06-10,Edge modes in active systems of subwavelength resonators,"Wave scattering structures with amplification and dissipation can be modelled
by non-Hermitian systems, opening new ways to control waves at small length
scales. In this work, we study the phenomenon of topologically protected edge
states in acoustic systems with gain and loss. We demonstrate that localized
edge modes appear in a periodic structure of subwavelength resonators with a
defect in the gain/loss distribution, and explicitly compute the corresponding
frequency and decay length. Similarly to the Hermitian case, these edge modes
can be attributed to the winding of the eigenmodes. In the non-Hermitian case,
the topological invariants fail to be quantized, but can nevertheless predict
the existence of localized edge modes.",2006.05719v1
2020-12-11,Nonresonant Diffusion in Alpha Channeling,"The gradient of fusion-born alpha particles that arises in a fusion reactor
can be exploited to amplify waves, which cool the alpha particles while
diffusively extracting them from the reactor. The corresponding extraction of
the resonant alpha particle charge has been suggested as a mechanism to drive
rotation. By deriving a coupled linear-quasilinear theory of alpha channeling,
we show that, for a time-growing wave with a purely poloidal wavevector, a
current in the nonresonant ions cancels the resonant alpha particle current,
preventing the rotation drive but fueling the fusion reaction.",2012.06532v1
2020-12-17,Photonic Lenses with Whispering Gallery Waves at Janus Particles,"We show that electric field on the plane surface of truncated sphere or
cylinders (so called Janus particles) have sharp resonances versus the depth of
removed segment of a sphere or cylinder. These resonances are related to the
excited whispering gallery waves caused by truncation. It is a new mechanism of
the field localization. Optimization of this effect for cylinders permits to
reach a super resolution in the line thickness what can be used for contacting
optical lithography.",2012.09489v1
2020-12-22,How Discrete Spectrum and Resonances Influence the Asymptotics of the Toda Shock Wave,"We rigorously derive the long-time asymptotics of the Toda shock wave in a
middle region where the solution is asymptotically finite gap. In particular,
we describe the influence of the discrete spectrum in the spectral gap on the
shift of the phase in the theta-function representation for this solution. We
also study the effect of possible resonances at the endpoints of the gap on
this phase. This paper is a continuation of research started in
[arXiv:2001.05184].",2012.12371v3
2021-05-13,The wave trace and resonances of the magnetic Hamiltonian with singular vector potentials,"We study leading order singularities of the wave trace of the Aharonov--Bohm
Hamiltonian on $\mathbf{R}^2$ with multiple solenoids under a generic
assumption that no three solenoids are collinear. Then we apply our formula to
get a lower bound of scattering resonances in a logarithmic neighborhood near
the real axis.",2105.06542v2
2021-07-29,Passive underwater acoustic barcodes using Rayleigh wave resonance,"A passive underwater acoustic marker is presented and its feasibility for
underwater recognition, positioning, and navigation is proved by a numerical
method and experimental results. These markers are composed of acrylic elastic
objects designed by backscattering strong peaks associated with the subsonic
Rayleigh wave resonance of a polymer target excited by a broadband pulse, and
having a unique acoustic signature for a selected frequency band, akin to
acoustic barcodes. Therefore, the backscattering response of markers can be
regulated by changing the geometry of elastic objects. These acoustic barcodes
naturally operate in a wider frequency band, and have a longer lifetime and
lower cost, compared with active acoustic markers.",2107.13860v1
2021-11-01,Four-wave mixing Floquet topological soliton,"We consider a topological Floquet insulator realized as a honeycomb array of
helical waveguides imprinted in weakly birefringent medium. The system accounts
for four-wave mixing occurring at a series of resonances arising due to Floquet
phase matching. Under these resonant conditions, the system sustains stable
linearly polarized and metastable elliptically polarized two-component edge
solitons. Coupled nonlinear equations describing evolution of the envelopes of
such solitons are derived.",2111.01293v2
2023-04-25,Time periodic solutions and Nekhoroshev stability to non-linear massive Klein-Gordon equations in Anti-de Sitter,"We prove the existence of time-periodic solutions to non-linear massive
Klein-Gordon equations in Anti-de Sitter as well as their orbital stability
over exponentially long times for certain values of the mass corresponding to
completely resonant spectrum. We analyse the resonant system in the Fourier
space by relying in particular on Zeilberger's algorithm which allows for a
systematic way to derive recurrence formulae for the Fourier coefficients. We
also show that the derivation and analysis of the Fourier systems easily
extends to other semi-linear wave equations such as the co-rotational wave map
equation.",2304.12784v1
2023-05-22,Standing Waves for Schrödinger Equations with Kato-Rellich potentials,"We show the existence of standing waves for the nonlinear Schr\""{o}dinger
equation with Kato-Rellich type potential. We consider both resonant with the
nonlinearity satisfying one of Landesman-Lazer type or sign conditions and
non-resonant case where the linearization at infinity has zero kernel. The
approach relies on the geometric and topological analysis of the parabolic
semiflow associated to the involved elliptic problem. Tail estimates techniques
and spectral theory of unbounded linear operators are used to exploit subtle
compactness properties necessary for use of the Conley index theory due to
Rybakowski.",2305.12877v1
2024-02-06,Probing early phase coarsening in a rapidly quenched Bose gas using off-resonant matter-wave interferometry,"We experimentally investigate the evolution of spatial phase correlations in
a rapidly quenched inhomogeneous Bose gas of rubidium using off-resonant
matter-wave interferometry. We measure the phase coherence length $\ell$ of the
sample and directly probe its increase during the early stage of condensate
growth before vortices are formed. Once the vortices are formed stably in the
quenched condensate, the measured value of $\ell$ is shown to be linearly
proportional to the mean distance between the vortices. These results confirm
the presence of phase coarsening prior to vortex formation, which is crucial
for a quantitative understanding of the resultant defect density in samples
undergoing critical phase transitions.",2402.03742v1
1997-12-03,Resonance Averaged Photoionization Cross Sections for Astrophysical Models,"We present ground state photoionization cross sections of atoms and ions
averaged over resonance structures for photoionization modeling of
astrophysical sources. The detailed cross sections calculated in the
close-coupling approximation using the R-matrix method, with resonances
delineated at thousands of energies, are taken from the Opacity Project
database TOPbase and the Iron Project, including new data for the low
ionization stages of iron Fe I--V. The resonance-averaged cross sections are
obtained by convolving the detailed cross sections with a Gaussian distribution
over the autoionizing resonances. This procedure is expected to minimize errors
in the derived ionization rates that could result from small uncertainties in
computed positions of resonances, while preserving the overall resonant
contribution to the cross sections in the important near threshold regions. The
detailed photoionization cross sections at low photon energies are complemented
by new relativistic distorted-wave calculations for Z<= 12, and from
central-field calculations for Z>12 at high energies, including inner-shell
ionization. The effective cross sections are then represented by a small number
of points that can be readily interpolated linearly for practical applications;
a Fortran subroutine and data are available. The present numerically averaged
cross sections are compared with analytic fits that do not accurately represent
the effective cross sections in regions dominated by resonances.",9712037v1
2010-03-27,Design of Optomechanical Cavities and Waveguides on a Simultaneous Bandgap Phononic-Photonic Crystal Slab,"In this paper we study and design quasi-2D optomechanical crystals,
waveguides, and resonant cavities formed from patterned slabs. Two-dimensional
periodicity allows for in-plane pseudo-bandgaps in frequency where resonant
optical and mechanical excitations localized to the slab are forbidden. By
tailoring the unit cell geometry, we show that it is possible to have a slab
crystal with simultaneous optical and mechanical pseudo-bandgaps, and for which
optical waveguiding is not compromised. We then use these crystals to design
optomechanical cavities in which strongly interacting, co-localized
photonic-phononic resonances occur. A resonant cavity structure formed by
perturbing a ""linear defect"" waveguide of optical and acoustic waves in a
silicon optomechanical crystal slab is shown to support an optical resonance at
wavelength 1.5 micron and a mechanical resonance of frequency 9.5 GHz. These
resonances, due to the simultaneous pseudo-bandgap of the waveguide structure,
are simulated to have optical and mechanical radiation-limited Q-factors
greater than 10^7. The optomechanical coupling of the optical and acoustic
resonances in this cavity due to radiation pressure is also studied, with a
quantum conversion rate, corresponding to the scattering rate of a single
cavity photon via a single cavity phonon, calculated to be 292 kHz.",1003.5265v2
2011-04-14,Resonances from meson-meson scattering in U(3) CHPT,"In this work, the complete one loop calculation of meson-meson scattering
amplitudes within U(3)\otimes U(3) chiral perturbation theory with explicit
resonance states is carried out for the first time. Partial waves are
unitarized from the perturbative calculation employing a non-perturbative
approach based on the N/D method. Once experimental data are reproduced in a
satisfactory way we then study the resonance properties, such as the pole
positions, corresponding residues and their N_C behaviors. The resulting N_C
dependence is the first one in the literature that takes into account the fact
that the \eta_1 becomes the ninth Goldstone boson in the chiral limit for large
N_C. Within this scheme the vector resonances studied, \rho(770), K^*(892) and
\phi(1020), follow an N_C trajectory in agreement with their standard \bar{q}q
interpretation. The scalars f_0(1370), a_0(1450) and K^*(1430) also have for
large N_C a \bar{q}q pole position trajectory and all of them tend to a bare
octet of scalar resonances around 1.4 GeV. The f_0(980) tends asymptotically to
the bare pole position of a singlet scalar resonance around 1 GeV. The \sigma,
\kappa and a_0(980) scalar resonances have a very different N_C behavior. The
case of the \sigma resonance is analyzed with special detail.",1104.2849v2
2011-09-09,Resonances formed by pbar-p and decaying into pizero-pizero-eta for masses 1960 to 2410 MeV,"Data on pbar-b annihilation in flight into pizero-pizero-eta are presented
for nine beam momenta 600 to 1940 MeV/c. The strongest four intermediate states
are found to be f_2(1270)-eta, a_2(1320)-pi, sigma-eta and a_0(980)-pi. Partial
wave analysis is performed mainly to look for resonances formed by pbar-p and
decaying into pizero-pizero-eta through these intermediate states. There is
evidence for the following s-channel I = 0 resonances : two 4^{++} resonances
with mass and width (M,Gamma) at (2044, 208) MeV and (2320+-30, 220+-30) MeV;
three 2^{++} resonances at (2020+-50, 200+-70) MeV, (2240+-40, 170+-50) MeV and
(2370+-50, 320+-50) MeV; two 3^{++} resonances at (2000+-40, 250+-40) MeV and
(2280+-30, 210+-30) MeV; a 1^{++} resonance at (2340+-40, 340+-40) MeV; and two
2^{-+} resonances at (2040+-40, 190+-40) MeV and (2300+-40, 270+-40) MeV.",1109.2086v1
2015-03-03,Evolutionary outcomes for pairs of planets undergoing orbital migration and circularization: second order resonances and observed period ratios in Kepler's planetary systems,"In order to study the origin of the architectures of low mass planetary
systems, we perform numerical surveys of the evolution of pairs of coplanar
planets in the mass range $(1-4)\ \rmn{M}_{\oplus}.$ These evolve for up to
$2\times10^7 \rmn{yr}$ under a range of orbital migration torques and
circularization rates assumed to arise through interaction with a
protoplanetary disc. Near the inner disc boundary, significant variations of
viscosity, interaction with density waves or with the stellar magnetic field
could occur and halt migration, but allow ircularization to continue. This was
modelled by modifying the migration and circularization rates. Runs terminated
without an extended period of circularization in the absence of migration
torques gave rise to either a collision, or a system close to a resonance.
These were mostly first order with a few $\%$ terminating in second order
resonances. Both planetary eccentricities were small $< 0.1$ and all resonant
angles liberated. This type of survey produced only a limited range of period
ratios and cannot reproduce Kepler observations. When circularization alone
operates in the final stages, divergent migration occurs causing period ratios
to increase. Depending on its strength the whole period ratio range between $1$
and $2$ can be obtained. A few systems close to second order commensurabilities
also occur. In contrast to when arising through convergent migration, resonant
trapping does not occur and resonant angles circulate. Thus the behaviour of
the resonant angles may indicate the form of migration that led to near
resonance.",1503.00906v3
2016-12-13,Omni-resonant optical micro-cavity,"Optical cavities are a cornerstone of photonics. They are indispensable in
lasers, optical filters, optical combs and clocks, in quantum physics, and have
enabled the detection of gravitational waves. Cavities transmit light only at
discrete resonant frequencies, which are well-separated in micro-structures.
Despite attempts at the construction of `white-light cavities', the benefits
accrued upon optically interacting with a cavity -- such as resonant field
buildup -- have remained confined to narrow linewidths. Here, we demonstrate
achromatic optical transmission through a planar Fabry-Perot micro-cavity via
angularly multiplexed phase-matching that exploits a bio-inspired grating
configuration. By correlating each wavelength with an appropriate angle of
incidence, a continuous spectrum resonates and the micro-cavity is rendered
transparent. The locus of a single-order 0.7-nm-wide resonance is de-slanted in
spectral-angular space to become a 60-nm-wide achromatic resonance spanning
multiple cavity free-spectral-ranges. This approach severs the link between the
resonance bandwidth and the cavity-photon lifetime, thereby promising resonant
enhancement of linear and nonlinear optical effects over broad bandwidths in
ultrathin devices.",1612.04328v1
2017-04-11,Frequency Response and Resonance of Elastic Hele-Shaw Cells with Application to Mechanical Filters,"We study steady-state oscillations of an elastic Hele-Shaw cell excited by
traveling pressure waves over its upper surface. The fluid within the cell is
bounded by two asymmetric elastic sheets which are connected to a rigid surface
via distributed springs and modeled by the linearized plate theory. Modal
analysis yields the frequency response of the configuration as a function of
three parameters: the fluidic Womersley number and two ratios of elastic stress
to viscous pressure for each of the sheets. These ratios, analogous to the
Capillary number, combine the effects of fluid viscosity and the sheets
inertia, bending and tension. The resonance frequencies of the configuration
include the resonance frequency of the upper sheet, and the resonance frequency
of both sheets with a constraint of constant gap. Near the resonance frequency
of the upper sheet, the fluid pressure is identical in amplitude and phase to
the external excitation. For configurations where both sheets are near
resonance, small changes in frequency yield significant modification of the
fluidic pressure. In addition, a new resonance frequency is observed, related
to the interaction between motion of fluid parallel to the elastic sheets and
relative elastic displacements of the sheets. The ratio of the amplitude of the
fluidic pressure to the external pressure is presented vs. frequency for
several characteristic solid and fluid properties, yielding a bandpass filter
behaviour. For configurations with a rigid lower surface the pressure ratio is
unity at the passband, while for two elastic sheets pressure amplification or
reduction occurs near the resonance frequencies. The results presented here may
allow to utilize elastic Hele-Shaw configurations as protective surfaces and
mechanical filters.",1704.03175v1
2019-07-31,Resonant photoproduction of high-energy electron-positron pairs in the field of a nucleus and a plane electromagnetic wave,"The resonant photoproduction of ultrarelativistic electron-positron pairs
(PPP) in a nuclear field and a weak laser field is theoretically studied. Under
resonance conditions, the intermediate virtual electron (positron) in the laser
field becomes a real particle. As a result, the initial process of the second
order in the fine structure constant in the laser field effectively reduces
into two successive processes of the first order: single-photon production of
electron-positron pair in a laser field (laser-stimulated Breit-Wheeler
process) and laser-assisted process of electron (positron) scattering on a
nucleus. Resonant kinematics of PPP is studied in details. It is shown that for
the considered laser intensities resonance is possible only for the initial
photon energies greater than the characteristic threshold energy. At the same
time, the ultrarelativistic electron and positron propagate in a narrow cone
along the direction of the initial photon momentum. The resonant energy of the
positron (electron) can has two values for each radiation angle which varies
from zero to some maximum value determined by the energy of the initial photon
and the threshold energy. Resonant differential cross section of the studied
process was obtained. It is shown that the resonant differential cross section
of the PPP can significantly exceed the corresponding cross section of the PPP
without an external field. The project calculations may be experimentally
verified by the scientific facilities of pulsed laser radiation (SLAC, FAIR,
XFEL, ELI, XCELS)",1907.13560v1
2020-12-15,Shifting and splitting of resonance lines due to dynamical friction in plasmas,"A quasilinear plasma transport theory that incorporates Fokker-Planck
dynamical friction (drag) and pitch angle scattering is self-consistently
derived from first principles for an isolated, marginally-unstable mode
resonating with an energetic minority species. It is found that drag
fundamentally changes the structure of the wave-particle resonance, breaking
its symmetry and leading to the shifting and splitting of resonance lines. In
contrast, scattering broadens the resonance in a symmetric fashion. Comparison
with fully nonlinear simulations shows that the proposed quasilinear system
preserves the exact instability saturation amplitude and the corresponding
particle redistribution of the fully nonlinear theory. Even in situations in
which drag leads to a relatively small resonance shift, it still underpins
major changes in the redistribution of resonant particles. This novel influence
of drag is equally important in plasmas and gravitational systems. In fusion
plasmas, the effects are especially pronounced for fast-ion-driven
instabilities in tokamaks with low aspect ratio or negative triangularity, as
evidenced by past observations. The same theory directly maps to the resonant
dynamics of the rotating galactic bar and massive bodies in its orbit,
providing new techniques for analyzing galactic dynamics.",2012.08661v2
2021-01-29,Electrokinetic oscillatory flow and energy conversion of viscoelastic fluids in microchannels: a linear analysis,"We study the electrokinetic flow of viscoelastic fluids subjected to an
oscillatory pressure gradient, and particularly focus on the resonance
behaviors in the flow. The governing equations are restricted to linear regime
so that the velocity and streaming potential fields can be solved analytically.
Based on the interaction of viscoelastic shear waves, we explain the mechanism
of resonance, and derive a critical Deborah number Dec = 1/4 which dictates the
occurrence of resonance. Using the Maxwell fluid model, we show that the
resonance enhances electrokinetic effects and results in a dramatic increase of
electrokinetic energy conversion efficiency. However, by applying the Oldroyd-B
fluid model it reveals that the amplification of efficiency is suppressed even
for a very small Newtonian solvent contribution. This may be one of the reasons
that experimental verification regarding the high efficiency predicted by
Bandopadhyay & Chakraborty (Appl. Phys. Lett., vol. 101, 2012, 043905) is
unavailable in the literature. Furthermore, the damping effect of solvent
viscosity is more significant for higher-order resonances. Introducing the
factor of multiple relaxation times, we show that the occurrence of resonances
for the streaming potential field and the flow rate are still dominated by Dec.
For the efficiency in the multi-mode case, the occurrence of resonance is
dominated by the Deborah number De and the mode number N, and the resonance
disappears for small De or large N. In addition, a new type of scaling relation
between the streaming potential field and EDL thickness can be identified at
large De.",2101.12517v1
2021-03-10,Assessing the impact of transient orbital resonances,"One of the primary sources for the future space-based gravitational wave
detector, the Laser Interferometer Space Antenna, are the inspirals of small
compact objects into massive black holes in the centres of galaxies. The
gravitational waveforms from such Extreme Mass Ratio Inspiral (EMRI) systems
will provide measurements of their parameters with unprecedented precision, but
only if the waveforms are accurately modeled. Here we explore the impact of
transient orbital resonances which occur when the ratio of radial and polar
frequencies is a rational number. We introduce a new Effective Resonance Model,
which is an extension of the numerical kludge EMRI waveform approximation to
include the effect of resonances, and use it to explore the impact of
resonances on EMRI parameter estimation. For one-year inspirals, we find that
the few cycle dephasings induced by 3:2 resonances can lead to systematic
errors in parameter estimates, that are up to several times the typical
measurement precision of the parameters. The bias is greatest for 3:2
resonances that occur closer to the central black hole. By regarding them as
unknown model parameters, we further show that observations will be able to
constrain the size of the changes in the orbital parameters across the
resonance to a relative precision of 10% for a typical one-year EMRI
observation with signal-to-noise ratio of 20. Such measurements can be regarded
as tests of fundamental physics, by comparing the measured changes to those
predicted in general relativity.",2103.06306v2
2021-07-18,"Widening, Transition and Coalescence of Local Resonance Band Gaps in Multi-resonator Acoustic Metamaterials: From Unit Cells to Finite Chains","Local resonance band gaps in acoustic metamaterials are widely known for
their strong attenuation yet narrow frequency span. The latter limits the
practical ability to implement subwavelength band gaps for broadband
attenuation and has motivated novel metamaterial designs in recent years. In
this paper, we investigate the behavior of acoustic metamaterials where unit
cells house multiple resonating elements stacked in different configurations,
aimed at instigating a wide array of wave propagation profiles that are
otherwise unattainable. The dispersion mechanics of the multi-resonator
metamaterials are developed using purely analytical expressions which depict
and explain the underlying dynamics of such systems both at the unit cell level
as well as the frequency response of their finite realizations. The framework
reveals the mechanism behind the transition of the lower and upper band gap
bounds in metamaterials with parallel resonators resulting in a significant
band gap widening. The analysis also illustrates the ability of metamaterials
with dual-periodic super cells to exhibit a range of dispersion transitions
culminating in collapsing solutions of acoustic and optic bands, enabling a
coalescence of local resonance band gaps, vanishing resonances, and a number of
intriguing scenarios in between.",2107.08431v4
2022-03-24,The gravitational imprint of an interior-orbital resonance in Jupiter-Io,"At mid-mission perijove 17, NASA's Juno mission has revealed a $7\sigma$
discrepancy between Jupiter's observed high-degree tidal response and the
theoretical equilibrium tidal response, namely the Love number $k_{42}$. Here,
we propose an interpretation for this puzzling disagreement based on an
interior-orbital resonance between internal gravity waves trapped in Jupiter's
dilute core and the orbital motion of Io. We use simple Jupiter models to
calculate a fractional correction $\Delta k_{42}$ to the equilibrium tidal
response that comes from the dynamical tidal response of a $g$-mode trapped in
Jupiter's dilute core. Our results suggest that an extended dilute core
($r\gtrsim0.7R_J$) produces an interior-orbital resonance with Io that modifies
Jupiter's tidal response in $\Delta k_{42}\sim-11\%$, allowing us to fit Juno's
$k_{42}$. In our proposed self-consistent scenario, Jupiter's dilute core
evolves in resonant locking with Io's orbital migration, which allows the
interior-orbital resonance to persist over geological timescales. This scenario
requires a dilute core that becomes smoother or shrinks over time, together
with a $_4^2g_1$ mode ($\ell,m,n=4,2,1$) with resonant tidal dissipation
reaching $Q_4\sim1000$. Jupiter's dilute core evolution path and the
dissipation mechanism for the resonant $_4^2g_1$ mode are uncertain and
motivate future analysis. No other alternative exists so far to explain the
$7\sigma$ discrepancy in Juno $k_{42}$. Our proposed interior-orbital resonance
can be tested by Juno observations of $k_{42}$ tides raised on Jupiter by
Europa as obtained at the end of the extended mission (mid 2025), and by future
seismological observations of Jupiter's $_4^2g_1$ mode oscillation frequency.",2203.13175v1
2000-03-28,Quantum Tunneling and Quantum-Classical Transitions in Large Spin Systems,"We have studied quantum tunneling of large spins in a biaxial spin system and
in a single-axial spin system with a transverse magnetic field. The
asymptotically exact eigenvalues and eigenstates of the spin systems are
obtained by solving the Mathieu equation. When the height $4q$ of energy
barrier formed by the anisotropy and the magnetic field exceeds some critical
values $4q_{1T}(r)$, the ground states and the excited states split due to
tunneling of large spins. We also have presented the phase diagram of these
spin systems in the extremely weak spin-phonon coupling limit. The crossover
from thermal to quantum regime is second order. With further decreasing
temperature, the first order phase transition occurs from a thermally-assisted
resonant tunneling to thermal regime as $q<q_{1T}(s)$. Our theory agrees with
recent experimental observations well.",0003440v1
2002-06-07,Spin-chirality duality in a spin ladder with four-spin cyclic exchange,"Effect of four-spin cyclic exchange on magnetism is studied in the two-leg
S=1/2 ladder. We develop an exact spin-chirality duality transformation, under
which the system is self-dual when the four-spin exchange J_4 is half of the
two-spin exchange. Using the density-matrix renormalization-group method and
the duality relation, we find that the four-spin exchange makes the vector
chirality correlation dominant. A ""chirality short-range
resonating-valence-bond"" phase is identified for the first time at large J_4.",0206102v2
2003-08-25,Initialization of a nuclear spin system over the quantum Hall regime for quantum information processing,"The application of the quantum mechanical properties of physical systems to
realize novel computational schemes and innovative device functions have been
topics of recent interest. Proposals for associated devices are to be found in
diverse branches of physics. Here, we are concerned with the experimental
realization of some elements needed for quantum information processing using
nuclear spin immersed in a confined electronic system in the quantum Hall
regime. Thus, we follow a spin-handling approach that (a) uses the Overhauser
effect in the quantum Hall regime to realize a large nuclear polarization at
relatively high temperatures, (b) detects the nuclear spin state by measuring
the influence of the associated magnetic field on Electron Spin Resonance, and
(c) seeks to apply the electronic spin exciton as the spin transfer mechanism.
Some measurements examining the viability of this approach are shown, and the
utility of the approach for initializing a nuclear spin system at a relatively
high temperature is pointed out",0308501v1
2004-01-29,Rashba spin-orbit coupling and spin relaxation in silicon quantum wells,"Silicon is a leading candidate material for spin-based devices, and
two-dimensional electron gases (2DEGs) formed in silicon heterostructures have
been proposed for both spin transport and quantum dot quantum computing
applications. The key parameter for these applications is the spin relaxation
time. Here we apply the theory of D'yakonov and Perel' (DP) to calculate the
electron spin resonance linewidth of a silicon 2DEG due to structural inversion
asymmetry for arbitrary static magnetic field direction at low temperatures. We
estimate the Rashba spin-orbit coupling coefficient in silicon quantum wells
and find the $T_{1}$ and $T_{2}$ times of the spins from this mechanism as a
function of momentum scattering time, magnetic field, and device-specific
parameters. We obtain agreement with existing data for the angular dependence
of the relaxation times and show that the magnitudes are consistent with the DP
mechanism. We suggest how to increase the relaxation times by appropriate
device design.",0401615v2
2004-04-03,Pumped spin-current and shot noise spectra in a single quantum dot,"We exploit the pumped spin-current and current noise spectra under
equilibrium condition in a single quantum dot connected to two normal leads, as
an electrical scheme for detection of the electron spin resonance (ESR) and
decoherence. We propose spin-resolved quantum rate equations with correlation
functions in Laplace-space for the analytical derivation of the zero-frequency
atuo- and cross-shot noise spectra of charge- and spin-current. Our results
show that in the strong Coulomb blockade regime, ESR-induced spin flip
generates a finite spin-current and the quantum partition noises in the absence
of net charge transport. Moreover, spin shot noise is closely related to the
magnetic Rabi frequency and decoherence and would be a sensitive tool to
measure them.",0404064v3
2004-09-08,Spin-dependent Andreev reflection tunneling through a quantum dot with intradot spin-flip scattering,"We study Andreev reflection (AR) tunneling through a quantum dot (QD)
connected to a ferromagnet and a superconductor, in which the intradot
spin-flip interaction is included. By using the nonequibrium-Green-function
method, the formula of the linear AR conductance is derived at zero
temperature. It is found that competition between the intradot spin-flip
scattering and the tunneling coupling to the leads dominantes resonant
behaviours of the AR conductance versus the gate voltage.A weak spin-flip
scattering leads to a single peak resonance.However, with the spin-flip
scattering strength increasing, the AR conductance will develop into a double
peak resonannce implying a novel structure in the tunneling spectrum of the AR
conductance. Besides, the effect of the spin-dependent tunneling couplings, the
matching of Fermi velocity, and the spin polarization of the ferromagnet on the
AR conductance is eximined in detail.",0409180v1
2004-09-13,DC Spin Current Generation in a Rashba-type Quantum Channel,"We propose and demonstrate theoretically that resonant inelastic scattering
(RIS) can play an important role in dc spin current generation. The RIS makes
it possible to generate dc spin current via a simple gate configuration: a
single finger-gate that locates atop and orients transversely to a quantum
channel in the presence of Rashba spin-orbit interaction. The ac biased
finger-gate gives rise to a time-variation in the Rashba coupling parameter,
which causes spin-resolved RIS, and subsequently contributes to the dc spin
current. The spin current depends on both the static and the dynamic parts in
the Rashba coupling parameter, $\alpha_0$ and $\alpha_1$, respectively, and is
proportional to $\alpha_0 \alpha_1^2$. The proposed gate configuration has the
added advantage that no dc charge current is generated. Our study also shows
that the spin current generation can be enhanced significantly in a double
finger-gate configuration.",0409291v3
2005-12-15,Enhancement of electron spin coherence by optical preparation of nuclear spins,"We study a large ensemble of nuclear spins interacting with a single electron
spin in a quantum dot under optical excitation and photon detection. When a
pair of applied laser fields satisfy two-photon resonance between the two
ground electronic spin states, detection of light scattering from the
intermediate exciton state acts as a weak quantum measurement of the effective
magnetic (Overhauser) field due to the nuclear spins. If the spin were driven
into a coherent population trapping state where no light scattering takes
place, then the nuclear state would be projected into an eigenstate of the
Overhauser field operator and electron decoherence due to nuclear spins would
be suppressed: we show that this limit can be approached by adapting the laser
frequencies when a photon is detected. We use a Lindblad equation to describe
the time evolution of the driven system under photon emission and detection.
Numerically, we find an increase of the electron coherence time from 5 ns to
500 ns after a preparation time of 10 microseconds.",0512362v1
2001-06-18,Algorithmic Cooling and Scalable NMR Quantum Computers,"We present here algorithmic cooling (via polarization-heat-bath)- a powerful
method for obtaining a large number of highly polarized spins in liquid
nuclear-spin systems at finite temperature. Given that spin-half states
represent (quantum) bits, algorithmic cooling cleans dirty bits beyond the
Shannon's bound on data compression, by employing a set of rapidly
thermal-relaxing bits. Such auxiliary bits could be implemented using spins
that rapidly get into thermal equilibrium with the environment, e.g., electron
spins.
  Cooling spins to a very low temperature without cooling the environment could
lead to a breakthrough in nuclear magnetic resonance experiments, and our
``spin-refrigerating'' method suggests that this is possible.
  The scaling of NMR ensemble computers is probably the main obstacle to
building useful quantum computing devices, and our spin-refrigerating method
suggests that this problem can be resolved.",0106093v1
2006-05-20,Polarization and readout of coupled single spins in diamond,"We study the coupling of a single nitrogen-vacancy center in diamond to a
nearby single nitrogen defect at room temperature. The magnetic dipolar
coupling leads to a splitting in the electron spin resonance frequency of the
nitrogen-vacancy center, allowing readout of the state of a single nitrogen
electron spin. At magnetic fields where the spin splitting of the two centers
is the same we observe a strong polarization of the nitrogen electron spin. The
amount of polarization can be controlled by the optical excitation power. We
combine the polarization and the readout in time-resolved pump-probe
measurements to determine the spin relaxation time of a single nitrogen
electron spin. Finally, we discuss indications for hyperfine-induced
polarization of the nitrogen nuclear spin.",0605179v2
2007-07-31,Coherent spin rotations in open driven double quantum dots,"We analyze the charge and spin dynamics in a DC biased double quantum dot
driven by crossed DC and AC magnetic fields. In this configuration, spatial
delocalization due to inter-dot tunnel competes with intra-dot spin rotations
induced by the time dependent magnetic field, giving rise to a complicated time
dependent behavior of the tunnelling current. When the Zeeman splitting has the
same value in both dots and spin flip is negligible, the electrons remain in
the triplet subspace (dark subspace) performing coherent spin rotations and the
current does not flow. This electronic trapping is removed either by finite
spin relaxation or when the Zeeman splitting is different in each quantum dot.
In the first case, our results show that measuring the current will allow to
get information on the spin relaxation time. In the last case, we will show
that applying a resonant bichromatic magnetic field, the electrons become
trapped in a coherent superposition of states and electronic transport is
blocked. Then, manipulating AC magnetic fields, electrons are driven to perform
coherent spin rotations which can be unambiguously detected by direct
measurement of the tunneling current.",0707.4636v2
2008-04-28,Coherent spin relaxation in molecular magnets,"Numerical modelling of coherent spin relaxation in nanomagnets, formed by
magnetic molecules of high spins, is accomplished. Such a coherent spin
dynamics can be realized in the presence of a resonant electric circuit coupled
to the magnet. Computer simulations for a system of a large number of
interacting spins is an efficient tool for studying the microscopic properties
of such systems. Coherent spin relaxation is an ultrafast process, with the
relaxation time that can be an order shorter than the transverse spin dephasing
time. The influence of different system parameters on the relaxation process is
analysed. The role of the sample geometry on the spin relaxation is
investigated.",0804.4368v1
2008-10-07,Coherent Manipulation and Decoherence of S=10 Single-Molecule Magnets,"We report coherent manipulation of S=10 Fe$_{8}$ single-molecule magnets. The
temperature dependence of the spin decoherence time $T_2$ measured by high
frequency pulsed electron paramagnetic resonance indicates that strong spin
decoherence is dominated by Fe$_{8}$ spin bath fluctuations. By polarizing the
spin bath in Fe$_{8}$ single-molecule magnets at magnetic field $B$ = 4.6 T and
temperature $T$ = 1.3 K, spin decoherence is significantly suppressed and
extends the spin decoherence time $T_2$ to as long as 712 ns. A second
decoherence source is likely due to fluctuations of the nuclear spin bath. This
hints that the spin decoherence time can be further extended via isotopic
substitution to smaller magnetic moments.",0810.1254v1
2008-11-03,Collective spin dynamics in magnetic nanomaterials,"Magnetic nanomaterials are considered, formed by magnetic nanomolecules with
high spins. The problem of spin reversal in these materials is analyzed, which
is of interest for the possible use of such materials for quantum information
processing and quantum computing. The fastest spin reversal can be achieved by
coupling the spin sample to a resonant electric circuit and by an appropriate
choice of the system parameters. A principal point is to choose these
parameters so that to organize coherent spin motion. Dynamics of collective
motion is modelled by computer simulations, which confirm the high level of
dynamical coherence of molecular spins in the process of spin reversal.",0811.0267v1
2009-05-13,Spin-dependent dipole excitation in alkali-metal nanoparticles,"We study the spin-dependent electronic excitations in alkali-metal
nanoparticles. Using numerical and analytical approaches, we focus on the
resonances in the response to spin-dependent dipole fields. In the spin-dipole
absorption spectrum for closed-shell systems, we investigate in detail the
lowest-energy excitation, the ""surface paramagnon"" predicted by L. Serra et al.
[Phys. Rev. A 47, R1601 (1993)]. We estimate its frequency from simple
assumptions for the dynamical magnetization density. In addition, we
numerically determine the dynamical magnetization density for all low-energy
spin-dipole modes in the spectrum. Those many-body excitations can be traced
back to particle-hole excitations of the noninteracting system. Thus, we argue
that the spin-dipole modes are not of collective nature. In open-shell systems,
the spin-dipole response to an electrical dipole field is found to increase
proportionally with the ground-state spin polarization.",0905.2076v1
2009-06-22,Theory of the spin relaxation of conduction electrons in silicon,"A realistic pseudopotential model is introduced to investigate the
phonon-induced spin relaxation of conduction electrons in bulk silicon. We find
a surprisingly subtle interference of the Elliott and Yafet processes affecting
the spin relaxation over a wide temperature range, suppressing the significance
of the intravalley spin-flip scattering, previously considered dominant, above
roughly 120 K. The calculated spin relaxation times $T_1$ agree with the spin
resonance and spin injection data, following a $T^{-3}$ temperature dependence.
The valley anisotropy of $T_1$ and the spin relaxation rates for hot electrons
are predicted.",0906.4054v4
2009-06-26,Nonlinear Spin-Charge Dynamics in a Driven Double Quantum Dot,"The coupled nonlinear coordinate and spin dynamics of an electron in a double
quantum dot with spin-orbit interaction is studied semiclassically. The system
is driven by an electric field with the frequency matching the orbital or the
Zeeman resonance in magnetic field. Calculated evolution of the spin state is
crucially sensitive to the irregularities in the spatial motion and the
geometry of the host nanostructure. The resulting spin-flip Rabi frequency has
an unusual dependence on the field amplitude, demonstrating approach to the
chaotic spin motion. In turn, the orbital dynamics depends strongly on the spin
evolution due to the spin-dependent term in the electron velocity.",0906.4854v1
2009-08-31,Hyperfine Interactions and Spin Transport in Ferromagnet-Semiconductor Heterostructures,"Measurements and modeling of electron spin transport and dynamics are used to
characterize hyperfine interactions in Fe/GaAs devices with $n$-GaAs channels.
Ga and As nuclei are polarized by electrically injected electron spins, and the
nuclear polarization is detected indirectly through the depolarization of
electron spins in the hyperfine field. The dependence of the electron spin
signal on injector bias and applied field direction is modeled by a coupled
drift-diffusion equation, including effective fields from both the electronic
and nuclear polarizations. This approach is used to determine the electron spin
polarization independently of the assumptions made in standard transport
measurements. The extreme sensitivity of the electron spin dynamics to the
nuclear spin polarization also facilitates the electrical detection of nuclear
magnetic resonance.",0909.0048v1
2010-04-16,Proposal of a full Bell state analyzer for spin qubits in a double quantum dot,"We propose a scheme for full Bell state measurement of spin qubits in a
double quantum dot. Our scheme consists of Pauli spin-blockade measurements and
biaxial electron-spin resonance. In order to eliminate the average of the
Zeeman fields, the double quantum dot is designed so that the Land\'e g-factors
of first and second dots satisfy g1=g2 with the use of g-factor engineering.
Thus, we can swap one of the three spin-triplet states for the spin-singlet
state without disturbing the other states. Our study shows that the sequential
spin-to-charge conversions enable us to implement the full Bell state
measurement of electron-spin qubits.",1004.2758v1
2010-05-10,Anisotropy of Magnetic Interactions in the Spin-Ladder Compound (C$_5$H$_{12}$N)$_2$CuBr$_4$,"Magnetic excitations in the spin-ladder material (C$_5$H$_{12}$N)$_2$CuBr$_4$
[BPCB] are probed by high-resolution multi-frequency electron spin resonance
(ESR) spectroscopy. Our experiments provide a direct evidence for a biaxial
anisotropy ($\sim 5\%$ of the dominant exchange interaction), that is in
contrast to a fully isotropic spin-ladder model employed for this system
previously. It is argued that this anisotropy in BPCB is caused by spin-orbit
coupling, which appears to be important for describing magnetic properties of
this compound. The zero-field zone-center gap in the excitation spectrum of
BPCB, $\Delta_0/k_{B}=16.5$ K, is detected directly. Furthermore, an ESR
signature of the inter-ladder exchange interactions is obtained. The detailed
characterization of the anisotropy in BPCB completes the determination of the
full spin hamiltonian of this exceptional spin-ladder material and shows ways
to study anisotropy effects in spin ladders.",1005.1474v1
2010-05-14,Perfect state transfers by selective quantum interferences within complex spin networks,"We present a method that implement directional, perfect state transfers
within a branched spin network by exploiting quantum interferences in the
time-domain. That provides a tool to isolate subsystems from a large and
complex one. Directionality is achieved by interrupting the spin-spin coupled
evolution with periods of free Zeeman evolutions, whose timing is tuned to be
commensurate with the relative phases accrued by specific spin pairs. This
leads to a resonant transfer between the chosen qubits, and to a detuning of
all remaining pathways in the network, using only global manipulations. As the
transfer is perfect when the selected pathway is mediated by 2 or 3 spins,
distant state transfers over complex networks can be achieved by successive
recouplings among specific pairs/triads of spins. These effects are illustrated
with a quantum simulator involving 13C NMR on Leucine's backbone; a six-spin
network.",1005.2593v1
2010-06-20,Inter-layer spin diffusion and electric conductivity in the organic conductors κ-ET2-Cl and κ-ET2-Br,"A high frequency (111.2-420 GHz) electron spin resonance study of the
inter-layer (perpendicular) spin diffusion as a function of pressure and
temperature is presented in the conducting phases of the layered organic
compounds, {\kappa}-(BEDT-TTF)2-Cu[N(CN)2]X ({\kappa}-ET2-X), X=Cl or Br. The
resolved ESR lines of adjacent layers at high temperatures and high frequencies
allows for the determination of the inter-layer cross spin relaxation time, Tx
and the intrinsic spin relaxation time, T2 of single layers. In the bad metal
phase spin diffusion is two-dimensional, i.e. spins are not hopping to adjacent
layers within T2. Tx is proportional to the perpendicular resistivity at least
approximately, as predicted in models where spin and charge excitations are
tied together. In {\kappa}-ET2-Cl, at zero pressure Tx increases as the bad
metal-insulator transition is approached. On the other hand, Tx decreases as
the normal metal and superconducting phases are approached with increasing
pressure and/or decreasing temperature.",1006.3939v1
2010-07-26,Fractional spin textures in the frustrated magnet SrCr$_{9p}$Ga$_{12-9p}$O$_{19}$,"We consider the archetypal frustrated antiferromagnet
SrCr$_{9p}$Ga$_{12-9p}$O$_{19}$ in its well-known spin-liquid state, and
demonstrate that a Cr$^{3+}$ spin $S=3/2$ ion in direct proximity to a pair of
vacancies (in disordered $p<1$ samples) is cloaked by a spatially extended spin
texture that encodes the correlations of the parent spin-liquid. In this
spin-liquid regime, the combined object has a magnetic response identical to a
classical spin of length $S/2 = 3/4$, which dominates over the small intrinsic
susceptibility of the pure system. This fractional-spin texture leaves an
unmistakable imprint on the measured $^{71}$Ga nuclear magnetic resonance (NMR)
lineshapes, which we compute using Monte-Carlo simulations and compare with
experimental data.",1007.4507v1
2010-08-24,Low temperature electron-spin relaxation in the crystalline and glassy states of solid ethanol,"X-band electron paramagnetic resonance (EPR) spectroscopy was used to study
the spectral properties of a nitroxide spin probe in ethanol glass and
crystalline ethanol, at 5 - 11.5 K. The different anisotropy of molecular
packing in the two host matrices was evidenced by different rigid limit values
for maximal hyperfine splitting in the signal of the spin probe. The
significantly shorter phase memory time, , for the spin probe dissolved in
crystalline ethanol, as compared to ethanol glass, was discussed in terms of
contribution from spectral diffusion. The effect of low-frequency dynamics was
manifested in the temperature dependence of and in the difference between the
data measured at different spectral positions. This phenomenon was addressed
within the framework of the slow-motional isotropic diffusion model [S. Lee,
and S. Z. Tang, Phys. Rev. B 31, 1308 (1985)] predicting the spin probe
dynamics within the millisecond range, at very low temperatures. The shorter
spin-lattice relaxation time of the spin probe in ethanol glass was interpreted
in terms of enhanced energy exchange between the spin system and the lattice in
the glass matrix due to boson peak excitations.",1008.4032v1
2011-05-25,Spin Relaxation Times of Single-Wall Carbon Nanotubes,"We have measured temperature ($T$)- and power-dependent electron spin
resonance in bulk single-wall carbon nanotubes to determine both the
spin-lattice and spin-spin relaxation times, $T_1$ and $T_2$. We observe that
$T_1^{-1}$ increases linearly with $T$ from 4 to 100 K, whereas $T_2^{-1}$ {\em
decreases} by over a factor of two when $T$ is increased from 3 to 300 K. We
interpret the $T_1^{-1} \propto T$ trend as spin-lattice relaxation via
interaction with conduction electrons (Korringa law) and the decreasing $T$
dependence of $T_2^{-1}$ as motional narrowing. By analyzing the latter, we
find the spin hopping frequency to be 285 GHz. Last, we show that the Dysonian
lineshape asymmetry follows a three-dimensional variable-range hopping behavior
from 3 to 20 K; from this scaling relation, we extract a localization length of
the hopping spins to be $\sim$100 nm.",1105.5095v3
2011-11-22,Spatial Analogue of Quantum Spin Dynamics via Spin-Orbit Interaction,"We map electron spin dynamics from time to space in quantum wires with
spatially uniform and oscillating Rashba spin-orbit coupling. The presence of
the spin-orbit interaction introduces pseudo-Zeeman couplings of the electron
spins to effective magnetic fields. We show that by periodically modulating the
spin-orbit coupling along the quantum wire axis, it is possible to create the
spatial analogue of spin resonance, without the need for any real magnetic
fields. The mapping of time-dependent operations onto a spatial axis suggests a
new mode for quantum information processing in which gate operations are
encoded into the band structure of the material. We describe a realization of
such materials within nanowires at the interface of LaAlO3/SrTiO3
heterostructures.",1111.5311v1
2011-11-30,Theory of the ac spin-valve effect,"The spin-valve complex magnetoimpedance of symmetric ferromagnet/normal
metal/ferromagnet junctions is investigated within the drift-diffusion
(standard) model of spin injection. The ac magnetoresistance---the real part
difference of the impedances of the parallel and antiparallel magnetization
configurations---exhibits an overall damped oscillatory behavior, as an
interplay of the diffusion and spin relaxation times. In wide junctions the ac
magnetoresistance oscillates between positive and negative values, reflecting
resonant amplification and depletion of the spin accumulation, while the line
shape for thin tunnel junctions is predicted to be purely Lorentzian. The ac
spin-valve effect could be a technique to extract spin transport and spin
relaxation parameters in the absence of a magnetic field and for a fixed sample
size.",1111.7244v1
2011-12-12,Spin-blockade effect and coherent control of DNA-damage by free radicals: a proposal on bio-spintronics,"Coherent control of OH-free radicals interacting with the spin-triplet state
of a DNA molecule is investigated. A model Hamiltonian for molecular spin
singlet-triplet resonance is developed. We illustrate that the spin-triplet
state in DNA molecules can be efficiently populated, as the spin-injection rate
can be tuned to be orders of magnitudes greater than the decay rate due to
small spin-orbit coupling in organic molecules. Owing to the nano-second
life-time of OH free radicals, a non-equilibrium free energy barrier induced by
the injected spin triplet state that lasts approximately longer than one-micro
second in room temperature can efficiently block the initial Hydrogen
abstraction and DNA damage. For a direct demonstration of the spin-blockade
effect, a molecular simulation based on an {\em ab-initio} Car-Parrinello
molecular dynamics is deployed.",1112.2733v1
2012-02-28,Spin-chain system as a tunable simulator of frustrated planar magnetism,"At low temperatures, weakly coupled spin chains develop a magnetic order that
reflects the character of gapless spin fluctuations along the chains. Using
nuclear magnetic resonance, we identify and characterize two ordered states in
the gapless region of the antiferromagnetic, Ising-like spin-chain system
BaCo2V2O8, both arising from the incommensurate fluctuations along the chains.
They correspond to the columnar and ferromagnetic ordered states of the
frustrated J1-J2 spin model on a square lattice, where the spins are encoded in
original spin chains. As a result of field-dependent incommensurate
fluctuations and frustrated interchain interaction, J1 can be tuned
continuously with the magnetic field, and its value with respect to a fixed J2
selects the ordered state. Spin-chain systems can thus be used as tunable
simulators of frustrated planar magnetism.",1202.6374v1
2012-05-30,Circuit Quantum Electrodynamics with a Spin Qubit,"Circuit quantum electrodynamics allows spatially separated superconducting
qubits to interact via a ""quantum bus"", enabling two-qubit entanglement and the
implementation of simple quantum algorithms. We combine the circuit quantum
electrodynamics architecture with spin qubits by coupling an InAs nanowire
double quantum dot to a superconducting cavity. We drive single spin rotations
using electric dipole spin resonance and demonstrate that photons trapped in
the cavity are sensitive to single spin dynamics. The hybrid quantum system
allows measurements of the spin lifetime and the observation of coherent spin
rotations. Our results demonstrate that a spin-cavity coupling strength of 1
MHz is feasible.",1205.6767v1
2013-03-16,Magnetoelectric effects and valley controlled spin quantum gates in transition metal dichalcogenide bilayers,"In monolayer group-VI transition metal dichalcogenides (TMDC), charge
carriers have spin and valley degrees of freedom, both associated with magnetic
moments. On the other hand, the layer degree of freedom in multilayers is
associated with electrical polarization. Here, we show that TMDC bilayers offer
an unprecedented platform to realize a strong coupling between the spin, layer
pseudospin, and valley degrees of freedom of holes. Such coupling not only
gives rise to the spin Hall effect and spin circular dichroism in inversion
symmetric bilayer, but also leads to a variety of magnetoelectric effects
permitting quantum manipulation of these electronic degrees of freedom.
Oscillating electric and magnetic fields can both drive the hole spin resonance
where the two fields have valley-dependent interference, making possible a
prototype interplay between the spin and valley as information carriers for
potential valley-spintronic applications. We show how to realize quantum gates
on the spin qubit controlled by the valley bit.",1303.3932v1
2013-04-17,A dual-isotope rubidium comagnetometer to search for anomalous long-range spin-mass (spin-gravity) couplings of the proton,"The experimental concept of a search for a long-range coupling between
rubidium (Rb) nuclear spins and the mass of the Earth is described. The
experiment is based on simultaneous measurement of the spin precession
frequencies for overlapping ensembles of Rb-85 and Rb-87 atoms contained within
an evacuated, antirelaxation-coated vapor cell. Rubidium atoms are
spin-polarized in the presence of an applied magnetic field by synchronous
optical pumping with circularly polarized laser light. Spin precession is
probed by measuring optical rotation of far-off-resonant, linearly polarized
laser light. Simultaneous measurement of Rb-85 and Rb-87 spin precession
frequencies enables suppression of magnetic-field-related systematic effects.
The nuclear structure of the Rb isotopes makes the experiment particularly
sensitive to anomalous spin-dependent interactions of the proton. Experimental
sensitivity and a variety of systematic effects are discussed, and initial data
are presented.",1304.4660v1
2013-05-07,High-Resolution Correlation Spectroscopy of 13C Spins Near a Nitrogen-Vacancy Center in Diamond,"Spin complexes comprising the nitrogen-vacancy (NV) center and neighboring
spins are being considered as a building block for a new generation of
spintronic and quantum information processing devices. Because assembling
identical spin clusters is difficult, new strategies are in order to determine
individual node structures with the highest precision. Here we use a pulse
protocol to monitor the time evolution of the 13C ensemble in the vicinity of a
NV center. We observe long-lived time correlations in the nuclear spin
dynamics, limited by NV spin-lattice relaxation. We use the host 14N spin as a
quantum register, and demonstrate that hyperfine-shifted resonances can be
separated upon proper NV initialization. Intriguingly, we find that the
amplitude of the correlation signal exhibits a sharp dependence on the applied
magnetic field. We discuss this observation in the context of the
quantum-to-classical transition proposed recently to explain the field
dependence of the spin cluster dynamics.",1305.1536v1
2013-05-28,Spin fluctuations with two-dimensional XY behavior in a frustrated S = 1/2 square-lattice ferromagnet,"The spin dynamics of the layered square-lattice vanadate Pb2VO(PO4)2 is
investigated by electron spin resonance at various magnetic fields and at
temperatures above magnetic ordering. The linewidth divergence towards low
temperatures seems to agree with isotropic Heisenberg-type spin exchange
suggesting that the spin relaxation in this quasi-two dimensional compound is
governed by low-dimensional quantum fluctuations. However, a weak easy- plane
anisotropy of the g factor points to the presence of a planar XY type of
exchange. Indeed, we found that the linewidth divergence is described best by
XY-like spin fluctuations which requires a single parameter only. Therefore,
ESR-probed spin dynamics could establish Pb2VO(PO4)2 as the first frustrated
square lattice system with XY-inherent spin topological fluctuations.",1305.6518v1
2013-06-27,High temperature collective spin-photon coupling in a microwave cavity,"An ensemble of N identical noninteracting spins being in thermal equilibrium
and coupled to the resonant mode of a lossless microwave cavity is studied at
arbitrary temperature T. Near T = 0 the system is known to be in a coupled
spin-photon state that manifests itself by the splitting of the cavity mode
(vacuum Rabi splitting). The cavity emission spectrum is simulated for
arbitrary T. It is shown that the spin-photon coherence can be partially
preserved for T < w sqrt{N}/2, where w is the spin excitation energy, even in
case when the spins are randomly directed. The calculations corroborate recent
room-temperature observations of the collective coupling between the microwave
cavity mode and the electron spin ensemble (NV centers in diamond, DPPH, Fe8
nanomagnets). At higher T, as a consequence of thermal excitations within the
spin ensemble, the two lines of the emission spectrum merge into a narrow line
with broad wings.",1306.6425v1
2013-10-22,Control of Majorana Edge Modes by a g-factor Engineered Nanowire Spin Transistor,"We propose the manipulation of Majorana edge states via hybridization and
spin currents in a nanowire spin transistor. The spin transistor is based on a
heterostructure nanowire comprising of semiconductors with large and small
g-factors that form the topological and non-topological regions respectively.
The hybridization of bound edge states results in spin currents and
$4\pi$-periodic torques, as a function of the relative magnetic field angle --
an effect which is dual to the fractional Josephson effect. We establish
relation between torques and spin-currents in the non-topological region where
the magnetic field is almost zero and spin is conserved along the spin-orbit
field direction. The angular momentum transfer could be detected by sensitive
magnetic resonance force microscopy techniques.",1310.5847v1
2014-08-27,Control of vibrational states by spin-polarized transport in a carbon nanotube resonator,"We study spin-dependent transport in a suspended carbon nanotube quantum dot
in contact with two ferromagnetic leads and with the dot's spin coupled to the
flexural mechanical modes. The spin-vibration interaction induces spin-flip
processes between the two energy levels of the dot. This interaction arises
from the spin-orbit coupling or a magnetic field gradient. The inelastic
vibration-assisted spin flips give rise to a mechanical damping and, for an
applied bias voltage, to a steady nonequilibrium occupation of the harmonic
oscillator. We analyze these effects as function of the energy-level separation
of the dot and the magnetic polarization of the leads. Depending on the
magnetic configuration and the bias-voltage polarity, we can strongly cool a
single mode or pump energy into it. In the latter case, we find that within our
approximation, the system approaches eventually a regime of mechanical
instability. Furthermore, owing to the sensitivity of the electron transport to
the spin orientation, we find signatures of the nanomechanical motion in the
current-voltage characteristic. Hence, the vibrational state can be read out in
transport measurements.",1408.6357v3
2014-09-17,Momentum resolved spin dynamics of bulk and surface excited states in the topological insulator $\mathrm{Bi_{2}Se_{3}}$,"The prospective of optically inducing a spin polarized current for spintronic
devices has generated a vast interest in the out-of-equilibrium electronic and
spin structure of topological insulators (TIs). In this Letter we prove that
only by measuring the spin intensity signal over several order of magnitude in
spin, time and angle resolved photoemission spectroscopy (STAR-PES) experiments
is it possible to comprehensively describe the optically excited electronic
states in TIs materials. The experiments performed on $\mathrm{Bi_{2}Se_{3}}$
reveal the existence of a Surface-Resonance-State in the 2nd bulk band gap
interpreted on the basis of fully relativistic ab-initio spin resolved
photoemission calculations. Remarkably, the spin dependent relaxation of the
hot carriers is well reproduced by a spin dynamics model considering two
non-interacting electronic systems, derived from the excited surface and bulk
states, with different electronic temperatures.",1409.5018v1
2014-09-29,Effectiveness of classical spin simulations for describing NMR relaxation of quantum spins,"We investigate the limits of effectiveness of classical spin simulations for
predicting free induction decays (FIDs) measured by solid-state nuclear
magnetic resonance (NMR) on systems of quantum nuclear spins. The specific
limits considered are associated with the range of interaction, the size of
individual quantum spins and the long-time behavior of the FID signals. We
compare FIDs measured or computed for lattices of quantum spins (mainly spins
1/2) with the FIDs computed for the corresponding lattices of classical spins.
Several cases of excellent quantitative agreement between quantum and classical
FIDs are reported along with the cases of gradually decreasing quality of the
agreement. We formulate semi-empirical criteria defining the situations, when
classical simulations are expected to accurately reproduce quantum FIDs. Our
findings indicate that classical simulations may be a quantitatively accurate
tool of first principles calculations for a broad class of macroscopic systems,
where individual quantum microscopic degrees of freedom are far from the
classical limit.",1409.8564v1
2014-11-03,Signatures of Majorana Zero Modes in Spin-Resolved Current Correlations,"We consider a normal lead coupled to a Majorana bound state. We show that the
spin-resolved current correlations exhibit unique features which distinguish
Majorana bound states from other low-energy resonances. In particular, the
spin-up and spin-down currents from a Majorana bound state are anti-correlated
at low bias voltages, and become uncorrelated at higher voltages. This behavior
is independent of the exact form of coupling to the lead, and of the direction
of the spin polarization. In contrast, an ordinary low-energy Andreev bound
state gives rise to a positive correlation between the spin-up and spin-down
currents, and this spin-resolved current-current correlation approaches a
non-zero constant at high bias voltages. We discuss experimental setups in
which this effect can be measured.",1411.0673v2
2014-11-25,Fast Electrical Control of Single Electron Spins in Quantum Dots with Vanishing Influence from Nuclear Spins,"We demonstrate fast universal electrical spin manipulation with inhomogeneous
magnetic fields. With fast Rabi frequency up to 127 MHz, we leave the
conventional regime of strong nuclear-spin influence and observe a spin-flip
fidelity > 96%, a distinct chevron Rabi pattern in the spectral-time domain,
and spin resonance linewidth limited by the Rabi frequency, not by the
dephasing rate. In addition, we establish fast z-rotations up to 54 MHz by
directly controlling the spin phase. Our findings will significantly facilitate
tomography and error correction with electron spins in quantum dots.",1411.6738v1
2015-01-28,Universal spin-triplet superconducting correlations of Majorana fermions,"We establish that Majorana fermions on the boundary of topological
superconductors have only spin-triplet superconducting correlations independent
of whether the bulk superconducting gap is spin singlet or triplet. This is
universal for time-reversal broken (respected) topological superconductors
(TSCs) with an odd number of (pairs of) Majorana fermions on the boundary.
Consequently, resonant Andreev reflection induced by Majorana fermions only
occurs in spin-triplet channels and always injects spin-triplet Cooper pairs
into the leads. This spin-triplet condensate results in a spin-orbit coupling
(SOC) controlled oscillatory critical current without a $0$-$\pi$ transition in
the TSC/SOC-semiconductor/TSC Josephson junction. The observation of this
unique current-phase relation can serve as the definitive signal for Majorana
fermions. Our study shows a technique for manipulating Majorana fermions based
on their spin-triplet superconducting correlations.",1501.07273v2
2015-07-30,Hierarchical spin-orbital polarisation of a giant Rashba system,"The Rashba effect is one of the most striking manifestations of spin-orbit
coupling in solids, and provides a cornerstone for the burgeoning field of
semiconductor spintronics. It is typically assumed to manifest as a
momentum-dependent splitting of a single initially spin-degenerate band into
two branches with opposite spin polarisation. Here, combining
polarisation-dependent and resonant angle-resolved photoemission measurements
with density-functional theory calculations, we show that the two ""spin-split""
branches of the model giant Rashba system BiTeI additionally develop disparate
orbital textures, each of which is coupled to a distinct spin configuration.
This necessitates a re-interpretation of spin splitting in Rashba-like systems,
and opens new possibilities for controlling spin polarisation through the
orbital sector.",1507.08588v1
2015-08-26,Spin Polarization Enhanced by Spin-Triplet Pairing in Sr$_2$RuO$_4$ Probed by NMR,"We report a novel phenomenon intimately related to the spin-triplet
superconductivity. It is well known that the spin susceptibility decreases
below the superconducting transition temperature in almost all superconductors
because of spin-singlet pair formation, while it may remain unchanged in a
handful of spin-triplet exceptions. Here we report the observation in
Sr$_2$RuO$_4$ with nuclear magnetic resonance (NMR) that the spin
susceptibility originating from the Ru-4$d$ electron slightly $increases$ by
$\sim 2 $\% of total and becomes inhomogeneous in the superconducting state.
These are reasonably explained if the electron pairs form the
equal-spin-pairing (ESP) in the mixed state. A similar phenomenon was predicted
for superfluid $^3$He forty years ago, but had never been demonstrated in any
superconductor.",1508.06421v1
2015-10-17,Direct evidence for minority spin gap in the Co2MnSi Heusler alloy,"Half Metal Magnets are of great interest in the field of spintronics because
of their potential full spin-polarization at the Fermi level and low
magnetization damping. The high Curie temperature and predicted 0.7eV minority
spin gap make the Heusler alloy Co2MnSi very promising for applications.We
investigated the half-metallic magnetic character of this alloy using
spin-resolved photoemission, ab initio calculation and ferromagnetic resonance.
At the surface of Co2MnSi, a gap in the minority spin channel is observed,
leading to 100% spin polarization. However, this gap is 0.3 eV below the Fermi
level and a minority spin state is observed at the Fermi level. We show that a
minority spin gap at the Fermi energy can nevertheless be recovered either by
changing the stoichiometry of the alloy or by covering the surface by Mn, MnSi
or MgO. This results in extremely small damping coefficients reaching values as
low as 7x 10-4.",1510.05085v1
2015-10-26,Magnetic field induced anisotropy of $^{139}\mathrm{La}$ spin-lattice relaxation rates in stripe ordered ${\mathrm{La}}_{1.875}{\mathrm{Ba}}_{0.125}{\mathrm{CuO}}_{4}$,"We report $^{139}$La nuclear magnetic resonance studies performed on a
La$_{1.875}$Ba$_{0.125}$CuO$_4$ single crystal. The data show that the
structural phase transitions (high-temperature tetragonal $\rightarrow$
low-temperature orthorhombic $\rightarrow$ low-temperature tetragonal phase)
are of the displacive type in this material. The $^{139}$La spin-lattice
relaxation rate $T_1^{-1}$ sharply upturns at the charge-ordering temperature
$T_\text{CO}$ = 54 K, indicating that charge order triggers the slowing down of
spin fluctuations. Detailed temperature and field dependencies of the
$T_1^{-1}$ below the spin-ordering temperature $T_\text{SO}$ = 40 K reveal the
development of enhanced spin fluctuations in the spin-ordered state for $H
\parallel [001]$, which are completely suppressed for large fields along the
CuO$_2$ planes. Our results shed light on the unusual spin fluctuations in the
charge and spin stripe ordered lanthanum cuprates.",1510.07529v1
2016-10-05,Prominent role of spin-orbit coupling in FeSe,"In most existing theories for iron-based superconductors, spin-orbit coupling
(SOC) has been assumed insignificant. Even though recent experiments have
revealed an influence of SOC on the electronic band structure, whether SOC
fundamentally affects magnetism and superconductivity remains an open question.
Here we use spin-polarised inelastic neutron scattering to show that collective
low-energy spin fluctuations in the orthorhombic (or ""nematic"") phase of FeSe
possess nearly no in-plane component. Such spin-space anisotropy can only be
caused by SOC. It is present over an energy range greater than the
superconducting gap 2$\Delta _\mathrm{sc}$ and gets fully inherited in the
superconducting state, resulting in a distinct $c$-axis polarised ""spin
resonance"". Our result demonstrates the importance of SOC in defining the
low-energy spin excitations in FeSe, which helps to elucidate the nearby
magnetic instabilities and the debated interplay between spin and orbital
degrees of freedom. The prominent role of SOC also implies a possible unusual
nature of the superconducting state.",1610.01277v1
2016-10-27,Purification of an unpolarized spin ensemble into entangled singlet pairs,"Dynamical polarization of nuclear spin ensembles is of central importance for
magnetic resonance studies, precision sensing and for applications in quantum
information theory. Here we propose a scheme to generate long-lived singlet
pairs in an unpolarized nuclear spin ensemble which is dipolar coupled to the
electron spins of a Nitrogen Vacancy center in diamond. The quantum mechanical
back-action induced by frequent spin-selective readout of the NV centers allows
the nuclear spins to pair up into maximally entangled singlet pairs.
Counterintuitively, the robustness of the pair formation to dephasing noise
improves with increasing size of the spin ensemble. We also show how the paired
nuclear spin state allows for enhanced sensing capabilities of NV centers in
diamond.",1610.08886v2
2017-11-09,Room Temperature Giant Charge-to-Spin Conversion at SrTiO3/LaAlO3 Oxide Interface,"Two-dimensional electron gas (2DEG) formed at the interface between SrTiO3
(STO) and LaAlO3 (LAO) insulating layer is supposed to possess strong Rashba
spin-orbit coupling. To date, the inverse Edelstein effect (i.e. spin-to-charge
conversion) in the 2DEG layer is reported. However, the direct effect of
charge-to-spin conversion, an essential ingredient for spintronic devices in a
current induced spin-orbit torque scheme, has not been demonstrated yet. Here
we show, for the first time, a highly efficient spin generation with the
efficiency of ~6.3 in the STO/LAO/CoFeB structure at room temperature by using
spin torque ferromagnetic resonance. In addition, we suggest that the spin
transmission through the LAO layer at high temperature range is attributed to
the inelastic tunneling via localized states in the LAO band gap. Our findings
may lead to potential applications in the oxide insulator based spintronic
devices.",1711.03268v1
2018-01-23,Density and $T_1$ of surface and bulk spins in diamond in high magnetic field gradients,"We report on surface and bulk spin density measurements of diamond, using
ultra-sensitive magnetic force microscopy with magnetic field gradients up to
0.5 T/$\mu$m. At temperatures between 25 and 800 mK, we measure the shifts in
the resonance frequency and quality factor of a cantilever with a micromagnet
attached to it. A recently developed theoretical analysis allows us to extract
a surface spin density of 0.072 spins/nm$^2$ and a bulk spin density of 0.4 ppm
from this data. In addition, we find an increase of the $T_1$ time of the
surface spins in high magnetic field gradients due to the suppression of spin
diffusion. Our technique is applicable to a variety of samples other than
diamond, and could be of interest for several research fields where surface,
interface or impurity bulk spin densities are an important factor.",1801.07535v1
2018-11-05,Nonadiabatic dynamics and geometric phase of an ultrafast rotating electron spin,"The spin in a rotating frame has attracted a lot of attentions recently, as
it deeply relates to both fundamental physics such as pseudo-magnetic field and
geometric phase, and applications such as gyroscopic sensors. However, previous
studies only focused on adiabatic limit, where the rotating frequency is much
smaller than the spin frequency. Here we propose to use a levitated
nano-diamond with a built-in nitrogen-vacancy (NV) center to study the dynamics
and the geometric phase of a rotating electron spin without adiabatic
approximation. We find that the transition between the spin levels appears when
the rotating frequency is comparable to the spin frequency at zero magnetic
field. Then we use Floquet theory to numerically solve the spin energy
spectrum, study the spin dynamics and calculate the geometric phase under a
finite magnetic field, where the rotating frequency to fulfill the resonant
transition condition could be greatly reduced.",1811.01641v1
2017-05-28,Breakdown of single spin-fluid model in heavily hole-doped superconductor CsFe2As2,"Although Fe-based superconductors are multiorbital correlated electronic
systems, previous nuclei magnetic resonance (NMR) measurement suggests that a
single spin-fluid model is sufficient to describe its spin behavior. Here, we
firstly observed the breakdown of single spin-fluid model in a heavily
hole-doped Fe-based superconductor CsFe2As2 by site-selective NMR measurement.
At high temperature regime, both of Knight shift and nuclei spin-lattice
relaxation at 133Cs and 75As nuclei exhibit distinct temperature-dependent
behavior, suggesting the breakdown of single spin-fluid model in CsFe2As2. This
is ascribed to the coexistence of both localized and itinerant spin degree of
freedom at 3d orbits, which is consistent with orbital-selective Mott phase.
However, single spin-fluid behavior is gradually recovered by developing a
coherent state among 3d orbits with decreasing temperature. A Kondo liquid
scenario is proposed for the low-temperature coherent state. The present work
sets strong constraint on the theoretical model for Fe-based superconductors.",1705.09885v1
2018-10-01,Determination of spin Hall angle in heavy metal/CoFeB-based heterostructures with interfacial spin-orbit fields,"Magnetization dynamics in W/CoFeB, CoFeB/Pt and W/CoFeB/Pt multilayers was
investigated using spin-orbit-torque ferromagnetic resonance (SOT-FMR)
technique. An analytical model based on magnetization dynamics due to SOT was
used to fit heavy metal (HM) thickness dependence of symmetric and
antisymmetric components of the SOT-FMR signal. The analysis resulted in a
determination of the properties of HM layers, such as spin Hall angle and spin
diffusion length. The spin Hall angle of -0.36 and 0.09 has been found in the
W/CoFeB and CoFeB/Pt bilayers, respectively, which add up in the case of
W/CoFeB/Pt trilayer. More importantly, we have determined effective interfacial
spin-orbit fields at both W/CoFeB and CoFeB/Pt interfaces, which are shown to
cancel Oersted field for particular thicknesses of the heavy metal layers,
leading to pure spin-current-induced dynamics and indicating the possibility
for a more efficient magnetization switching.",1810.00641v1
2018-12-03,Spin decoherence independent of antiferromagnetic order in IrMn,"We investigate the impact of pinned antiferromagnetic order on the
decoherence of spin current in polycrystalline IrMn. In NiFe/Cu/IrMn/CoFe
multilayers, we coherently pump an electronic spin current from NiFe into IrMn,
whose antiferromagnetic order is globally pinned by static exchange-bias
coupling with CoFe. We observe no anisotropic spin decoherence with respect to
the orientation of the pinned antiferromagnetic order. We also observe no
difference in spin decoherence for samples with and without pinned
antiferromagnetic order. Moreover, although there is a pronounced resonance
linewidth increase in NiFe that coincides with the switching of IrMn/CoFe, we
show that this is not indicative of anisotropic spin decoherence in IrMn. Our
results demonstrate that the decoherence of electron-mediated spin current is
remarkably insensitive to the magnetization state of the antiferromagnetic IrMn
spin sink.",1812.00702v1
2020-04-23,Nanoscale Detection of Magnon Excitations with Variable Wavevectors Through a Quantum Spin Sensor,"We report the optical detection of magnons with a broad range of wavevectors
in magnetic insulator Y3Fe5O12 thin films by proximate nitrogen-vacancy (NV)
single-spin sensors. Through multi-magnon scattering processes, the excited
magnons generate fluctuating magnetic fields at the NV electron spin resonance
frequencies, which accelerate the relaxation of NV spins. By measuring the
variation of the emitted spin-dependent photoluminescence of the NV centers,
magnons with variable wavevectors up to ~ 5 x 10^7 m-1 can be optically
accessed, providing an alternative perspective to reveal the underlying spin
behaviors in magnetic systems. Our results highlight the significant
opportunities offered by NV single-spin quantum sensors in exploring nanoscale
spin dynamics of emergent spintronic materials.",2004.11067v1
2016-03-26,Direct coupling between charge current and spin polarization by extrinsic mechanisms in graphene,"Spintronics---the all-electrical control of the electron spin for quantum or
classical information storage and processing---is one of the most promising
applications of the two-dimensional material graphene. Although pristine
graphene has negligible spin-orbit coupling (SOC), both theory and experiment
suggest that SOC in graphene can be substantially enhanced by extrinsic means,
such as functionalization by adatom impurities. We present a theory of
transport in graphene that accounts for the full spin-coherent dynamics of the
carriers, including hitherto-neglected spin precession processes during
resonant scattering with dilute impurities. We identify a novel ""anisotropic
spin precession scattering"" process, specific to two dimensions and extrinsic
SOC, which contributes to a large current-induced spin polarization in
graphene. The theory also yields a comprehensive description of the spin
relaxation mechanisms in impurity-decorated graphene: the Elliot-Yafet and
Dyakonov-Perel relaxation rates are both present, and we find that the latter
can dominate for some choices of carrier density and impurity strength. This
provides theoretical foundations for designing future graphene-based integrated
spintronic devices.",1603.08107v2
2017-02-13,Inter-valley dark trion states with spin lifetimes of 150 ns in WSe$_2$,"We demonstrate long trion spin lifetimes in a WSe$_2$ monolayer of up to 150
ns at 5 K. Applying a transverse magnetic field in time-resolved Kerr-rotation
measurements reveals a complex composition of the spin signal of up to four
distinct components. The Kerr rotation signal can be well described by a model
which includes inhomogeneous spin dephasing and by setting the trion spin
lifetimes to the measured excitonic recombination times extracted from
time-resolved reflectivity measurements. We observe a continuous shift of the
Kerr resonance with the probe energy, which can be explained by an
adsorbate-induced, inhomogeneous potential landscape of the WSe$_2$ flake. A
further indication of extrinsic effects on the spin dynamics is given by a
change of both the trion spin lifetime and the distribution of g-factors over
time. Finally, we detect a Kerr rotation signal from the trion's higher-energy
triplet state when the lower-energy singlet state is optically pumped by
circularly polarized light. We explain this by the formation of dark trion
states, which are also responsible for the observed long trion spin lifetimes.",1702.03712v1
2017-06-27,Optical and spin properties of a single praseodymium ion in a crystal,"The investigation of single atoms in solids, with both optical and nuclear
spin access is of particularly interest with applications ranging from
nanoscale sensing to quantum computation. Here, we study the optical and spin
properties of single praseodymium ions in an yttrium aluminum garnet (YAG)
crystal at cryogenic temperature. The single nuclear spin of single
praseodymium ions is detected through a background-free optical upconverting
readout technique. Single ions show stable photoluminescence (PLE) with
spectrally resolved hyperfine splitting of the praseodymium ground state. Based
on this measurement, optical Rabi and optically detected magnetic resonance
(ODMR) measurements are performed to study the spin coherence properties. Our
results reveal that the spin coherence time of single praseodymium nuclear
spins is limited by the strong spin-phonon coupling at experimental
temperature.",1706.08736v2
2017-10-10,Co-tunneling spin blockade observed in a three-terminal triple quantum dot,"We prepare a triple quantum dot with a separate contact lead to each dot to
study Pauli spin blockade in the tunnel-coupled three dots in a row. We measure
the tunneling current flowing between the center dot and either the left or
right dot with the left and right leads as a common source and the center lead
as a drain. In the biased stability diagram, we establish Pauli spin blockade
in the respective neighboring dots, with features similarly obtained in double
quantum dot systems. We further realize Pauli spin blockade with two different
conditions by tuning the inter-dot coupling gates: strong and weak inter-dot
tunnel coupling regimes. In the strong-coupling regime we observe significant
suppression of co-tunneling through the respective double dots due to Pauli
spin blockade. We reveal the influence from the third dot in the triple dot
device on this co-tunneling Pauli spin blockade and clarify that the
co-tunneling Pauli spin blockade is lifted by the resonant coupling of excited
states to the third dot level as well as spin exchange of the left and right
dots with the adjacent reservoir.",1710.03378v1
2017-10-13,Optical holonomic single quantum gates with a geometric spin under a zero field,"Realization of fast fault-tolerant quantum gates on a single spin is the core
requirement for solid-state quantum-information processing. As polarized light
shows geometric interference, spin coherence is also geometrically controlled
with light via the spin-orbit interaction. Here, we show that a geometric spin
in a degenerate subspace of a spin-1 electronic system under a zero field in a
nitrogen vacancy center in diamond allows implementation of optical
non-adiabatic holonomic quantum gates. The geometric spin under quasi-resonant
light exposure undergoes a cyclic evolution in the spin-orbit space, and
acquires a geometric phase or holonomy that results in rotations about an
arbitrary axis by any angle defined by the light polarization and detuning.
This enables universal holonomic quantum gates with a single operation. We
demonstrate a complete set of Pauli quantum gates using the geometric spin
preparation and readout techniques. The new scheme opens a path to holonomic
quantum computers and repeaters.",1710.04885v1
2019-03-03,Near-Unity Spin Hall Ratio in Ni$_x$Cu$_{1-x}$ Alloys,"We report a large spin Hall effect in the 3$d$ transition metal alloy
Ni$_x$Cu$_{1-x}$ for $x\in\left\{ 0.3,0.75\right\} $, detected via the
ferromagnetic resonance of a Permalloy (Py = Ni$_{80}$Fe$_{20}$) film deposited
in a bilayer with the alloy. A thickness series at $x$ = 0.6, for which the
alloy is paramagnetic at room temperature, allows us to determine the spin Hall
ratio $\theta_{\rm{SH}}\approx1$, spin diffusion length $\lambda_{\rm{s}}$,
spin mixing conductance $G_{\uparrow\downarrow}$, and damping
$\alpha_{\rm{SML}}$ due to spin memory loss . We compare our results with
similar experiments on Py/Pt bilayers measured using the same method. Ab initio
band structure calculations with disorder and spin-orbit coupling suggest an
intrinsic spin Hall effect in Ni$_x$Cu$_{1-x}$ alloys, although the experiments
here cannot distinguish between extrinsic and intrinsic mechanisms.",1903.00910v2
2019-03-22,Exceptional points in classical spin dynamics,"Non-conservative physical systems admit a special kind of spectral
degeneracy, known as exceptional point (EP), at which eigenvalues and
eigenvectors of the corresponding non-Hermitian Hamiltonian coalesce. Dynamical
parametric encircling of the EP can lead to non-adiabatic evolution associated
with a state flip, a sharp transition between the resonant modes. Physical
consequences of the dynamical encircling of EPs in open dissipative systems
have been explored in optics and photonics. Building on the recent progress in
understanding the parity-time (PT)-symmetric dynamics in spin systems, we use
topological properties of EPs to implement chiral non-reciprocal transmission
of a spin through the material with non-uniform magnetization, like helical
magnet. We consider an exemplary system, spin-torque-driven single spin
described by the time-dependent non-Hermitian Hamiltonian. We show that
encircling individual EPs in parameter space results in non-reciprocal spin
dynamics and find the range of optimal protocol parameters for high-efficiency
asymmetric spin filter based on this effect. Our findings offer a platform for
non-reciprocal spin devices for spintronics and magnonics.",1903.09729v2
2020-03-28,Spin transport and dynamic properties of two-dimensional spin-momentum locked states,"Materials with spin-momentum locked surface or interface states provide an
interesting playground for studying physics and application of charge-spin
current conversion. To characterize their non-equilibrium magnetic and
transport properties in the presence of a time-dependent external magnetic
field and a spin injection from a contact, we introduce three macroscopic
variables: a vectorial helical magnetization, a scaler helical magnetization,
and the conventional magnetization. We derive a set of closed dynamic equations
for these variables by using the spinor Boltzmann approach with the collision
terms consistent with the symmetry of spin-momentum locked states. By solving
the dynamic equations, we predict several intriguing magnetic and transport
phenomena which are experimentally accessible, including magnetic resonant
response to an AC applied magnetic field, charge-spin conversion, and spin
current induced by the dynamics of helical magnetization.",2003.12700v1
2020-11-27,Experimental Detection of the Correlation Rényi Entropy in the Central Spin Model,"We propose and experimentally measure an entropy that quantifies the volume
of correlations among qubits. The experiment is carried out on a nearly
isolated quantum system composed of a central spin coupled and initially
uncorrelated with 15 other spins. Due to the spin-spin interactions,
information flows from the central spin to the surrounding ones forming
clusters of multi-spin correlations that grow in time. We design a nuclear
magnetic resonance experiment that directly measures the amplitudes of the
multi-spin correlations and use them to compute the evolution of what we call
correlation R\'enyi entropy. This entropy keeps growing even after the
equilibration of the entanglement entropy. We also analyze how the saturation
point and the timescale for the equilibration of the correlation R\'enyi
entropy depend on the system size.",2011.13948v1
2021-10-05,Fractional spin excitations and conductance in the spiral staircase Heisenberg ladder,"We investigate theoretically the spiral staircase Heisenberg spin-$1/2$
ladder in the presence of antiferromagnetic long-range spin interactions and a
uniform magnetic field. As a special case we also consider the Kondo necklace
model. If the magnetizations of the two chains forming the ladder satisfy a
certain resonance condition, involving interchain couplings as perturbations,
the system is in a partially gapped magnetic phase hosting excitations
characterized by fractional spins, whose values can be changed by the magnetic
field. We show that these fractional spin excitations can be probed by spin
currents in a transport setup with a spin conductance that reveals the
fractionalized spin. In some special cases, the spin conductance reaches
universal values in units of $(g\mu_B)^2/h$, where $g$ is the $g$-factor,
$\mu_B$ the Bohr magneton, and $h$ the Planck constant. We obtain our results
with the help of bosonization and numerical density matrix renormalization
group methods.",2110.02130v2
2021-10-06,Dissipation-assisted preparation of steady spin-squeezed states of SiV centers,"We propose an efficient scheme for generating spin-squeezed states at steady
state in a spin-mechanical hybrid system, where an ensemble of SiV centers are
coupled to a strongly damped nanomechanical resonator. We show that,there
exists a collective steady state in the system, which is exactly formed by the
collective spin states plus the zero excitation state of the mechanical mode.
The generation of the steady spin-squeezed state is based on a dissipative
quantum dynamical process in which the mechanical dissipation plays a positive
role but without destroying the target state. We demonstrate that the
spin-squeezed steady state can be deterministically prepared via dissipative
means, with the optimal spin squeezing up to 4/N in the ideal case, where N is
the number of spins. This work provides a promising platform for quantum
information processing and quantum metrology.",2110.02837v1
2008-06-17,Effect of environmental spins on Landau-Zener transitions,"Landau-Zener (LZ) transitions of a two-level system (e. g., electronic spin
in molecular magnets) coupled to one or many environmental spins (e. g.,
nuclear spins) are studied. For rather general interactions the LZ problem is
reduced to that of a Landau-Zener grid. It is shown analytically that
environmental spins initially in their ground state do not influence the
staying probability P. This changes if they are prepared in a statistical
ensemble. For a more specific model with environmental spins in a transverse
field, LZ transitions are studied in the case of well-separated resonances in
the LZ grid. The full evolution of the system is described as a succession of
elemenary transitions at avoided crossings and free evolution between them. If
the environmental spins are strongly coupled to the central spin, their effect
on P is weak. In other cases LZ transitions are strongly suppressed and P is
decreasing very slowly with the sweep-rate parameter epsilon ~ 1/v, v being the
energy sweep rate.",0806.2830v1
2017-04-20,Dynamics of a j=3/2 quantum spin liquid,"We study a spin-orbital model for 4$d^{1}$ or 5$d^{1}$ Mott insulators in
ordered double perovskites with strong spin-orbit coupling. This model is
conveniently written in terms of pseudospin and pseudo-orbital operators
representing multipoles of the effective $j=3/2$ angular momentum. Similarities
between this model and the effective theories of Kitaev materials motivate the
proposal of a chiral spin-orbital liquid with Majorana fermion excitations. The
thermodynamic and spectroscopic properties of this quantum spin liquid are
characterized using parton mean-field theory. The heat capacity, spin-lattice
relaxation rate, and dynamic structure factor for inelastic neutron scattering
are calculated and compared with the experimental data for the spin liquid
candidate Ba$_{2}$YMoO$_{6}$. Moreover, based on a symmetry analysis, we
discuss the operators involved in resonant inelastic X-ray scattering (RIXS)
amplitudes for double perovskite compounds. In general, the RIXS cross sections
allow one to selectively probe pseudospin and pseudo-orbital degrees of
freedom. For the chiral spin-orbital liquid in particular, these cross sections
provide information about the spectrum for different flavors of Majorana
fermions.",1704.06134v3
2019-09-24,Manipulation of Inverse Spin Hall Effect in Palladium by Absorption of Hydrogen Gas,"The spintronic properties of a palladium thin film have been investigated in
the presence of hydrogen gas in cobalt/palladium bilayers. Measurements of the
inverse spin Hall Effect (ISHE) using cavity ferromagnetic resonance allow
estimations of the spin Hall conductivity and spin diffusion length in both
nitrogen and hydrogen gas atmospheres. Unwanted spin rectification effects are
removed using a simple method of inverting the spin current direction with
respect to the measurement setup. Absorption of hydrogen gas in the Pd layer at
just 3% concentration results in a reduced ISHE voltage amplitude and bilayer
resistance. Fitting the ISHE voltage against the Pd layer thickness
demonstrates that the spin diffusion length decreases by 23% in the presence of
a hydrogen gas. On the other hand, the results indicate that there is no
significant change in the spin Hall conductivity of Pd due to hydrogen
absorption.",1909.10661v1
2020-06-11,Observation of a strongly ferromagnetic spinor Bose-Einstein condensate,"We report the observation of strongly ferromagnetic $F=1$ spinor
Bose-Einstein condensates of $^7$Li atoms. The condensates are generated in an
optical dipole trap without using magnetic Feshbach resonances, so that the
condensates have internal spin degrees of freedom. Studying the non-equilibrium
spin dynamics, we have measured the ferromagnetic spin interaction energy and
determined the $s$-wave scattering length difference among total spin $f$
channels to be $a_{f=2}-a_{f=0} =-18(3)$ Bohr radius. This strong
collision-channel dependence leads to a large variation in the condensate size
with different spin composition. We were able to excite a radial monopole mode
after a spin-flip transition between the $|m_F=0\rangle$ and $|m_F=1\rangle$
spin states. From the experiments, we estimated the scattering length ratio
$a_{f=2}/a_{f=0}=0.27(6)$, and determined $a_{f=2}$ = 7(2) and $a_{f=0}$ =
25(5) Bohr radii, respectively. The results indicate the spin-dependent
interaction energy of our system is as large as 46$\%$ of the condensate
chemical potential.",2006.06228v1
2020-12-06,Femtosecond Laser Writing of Spin Defects in Hexagonal Boron Nitride,"Optically active spin defects in wide-bandgap materials have many potential
applications in quantum information and quantum sensing. Spin defects in
two-dimensional layered van der Waals materials are just emerging to be
investigated. Here we demonstrate that optically-addressable spin ensembles in
hexagonal boron nitride (hBN) can be generated by femtosecond laser
irradiation. We observe optically detected magnetic resonance (ODMR) of hBN
spin defects created by laser irradiation. We show that the creation of spin
defects in hBN is strongly affected by the pulse energy of the femtosecond
laser. When the laser pulse number is less than a few thousand, the pulse
number only affects the density of defects but not the type of defects. With
proper laser parameters, spin defects can be generated with a high probability
of success. Our work provides a convenient way to create spin defects in hBN by
femtosecond laser writing, which shows promising prospects for quantum
technologies.",2012.03207v2
2021-05-12,Probing Strong Coupling between a Microwave Cavity and a Spin Ensemble with Raman Heterodyne Spectroscopy,"Raman heterodyne spectroscopy is a powerful tool for characterizing the
energy and dynamics of spins. The technique uses an optical pump to transfer
coherence from a spin transition to an optical transition where the coherent
emission is more easily detected.
  Here Raman heterodyne spectroscopy is used to probe an isotopically purified
ensemble of erbium dopants, in a yttrium orthosilicate (Y$_2$SiO$_5$) crystal
coupled to a microwave cavity. Because the erbium electron spin transition is
strongly coupled to the microwave cavity, we observed Raman heterodyne signals
at the resonant frequencies of the hybrid spin-cavity modes (polaritons) rather
than the bare erbium spin transition frequency. Using the coupled system, we
made saturation recovery measurements of the ground state spin relaxation time
T$_1$ = 10$\pm$3 seconds, and also observed Raman heterodyne signals using an
excited state spin transition. We discuss the implications of these results for
efforts towards converting microwave quantum states to optical quantum states.",2105.05387v1
2021-06-08,One-directional polarization transport in electron/nuclear spin chains with loss and gain,"Understanding the joint dynamics of electron and nuclear spins is central to
core concepts in solid-state magnetic resonance - such as spin-lattice
relaxation and dynamic nuclear polarization - but a generalization that
capitalizes on competing polarization loss and gain channels is still lacking.
Here, we theoretically study the non-Hermitian dynamics of hybrid
electron/nuclear spin systems in the simultaneous presence of electron spin
pumping and spin-lattice relaxation. Focusing on periodic, one-dimensional
chains, we find that by adjusting the electron spin pumping to a critical
level, it is possible to steer the flow of nuclear polarization to create
site-dependent distributions where either end of the array polarizes in
opposite ways, irrespective of the initial state. By contrast, we show that
ring-like patterns - where the limit nuclear polarization is uniform - exhibit
a non-decaying, externally-driven nuclear spin current. Interestingly, cyclic
magnetic field modulation can render these processes largely robust to defects
in the chain, a response featuring some interesting similarities - and
differences - with recent findings in other non-Hermitian physical platforms.",2106.04326v1
2021-06-28,The emergent linear Rashba spin-orbit coupling offering the fast manipulation of hole-spin qubits in germanium,"The electric dipole spin resonance (EDSR) combining strong spin-orbit
coupling (SOC) and electric-dipole transitions facilitates fast spin control in
a scalable way, which is the critical aspect of the rapid progress made
recently in germanium (Ge) hole-spin qubits. However, a puzzle is raised
because centrosymmetric Ge lacks the Dresselhaus SOC, a key element in the
initial proposal of the hole-based EDSR. Here, we demonstrate that the recently
uncovered finite k-linear Rashba SOC of 2D holes offers fast hole spin control
via EDSR with Rabi frequencies in excellent agreement with experimental results
over a wide range of driving fields. We also suggest that the Rabi frequency
can reach 500 MHz under a higher gate electric field or multiple GHz in a
replacement by [110]oriented wells. These findings bring a deeper understanding
for hole-spin qubit manipulation and offer design principles to boost the gate
speed.",2106.14684v2
2021-07-21,Dynamics of two ferromagnetic insulators coupled by superconducting spin current,"A conventional superconductor sandwiched between two ferromagnets can
maintain coherent equilibrium spin current. This spin supercurrent results from
the rotation of odd-frequency spin correlations induced in the superconductor
by the magnetic proximity effect. In the absence of intrinsic magnetization,
the superconductor cannot maintain multiple rotations of the triplet component
but instead provides a Josephson type weak link for the spin supercurrent. We
determine the analogue of the current-phase relation in various circumstances
and show how it can be accessed in experiments on dynamic magnetization. In
particular, concentrating on the magnetic hysteresis and the ferromagnetic
resonance response, we show how the spin supercurrent affects the
nonequilibrium dynamics of magnetization which depends on a competition between
spin supercurrent mediated static exchange contribution and a dynamic spin
pumping contribution. Depending on the outcome of this competition, a mode
crossing in the system can either be an avoided crossing or mode locking.",2107.09959v2
2021-12-09,Electronic control and switching of entangled spin state using anisotropy and exchange in the three-particle paradigm,"We explore the control and switching of the entangled spin states of
multi-spin particle qubit coupled to an electron using a three-particle spin
model described by $S_i$ ($i=1,2,3$), in which $S_1=\tfrac{1}{2}$ is an
electron and $S_{2,3}$ can have any spin with both exchange coupling and
magnetic anisotropy. We derive a general formula for the existence of a
switching (DJ) resonance for any spin $S_{2,3}$. We further contrast the
entanglement switching mechanisms for the $S_{2,3}=\tfrac{1}{2}$ and
$S_{2,3}=1$ spin models. We find that while the onsite magnetic anisotropy in
the case of $S_{2,3}>\tfrac{1}{2}$ allows full control of their spin states via
interaction with $S_1$, in order to achieve acceptable control of a Bloch
vector within the $S_{2,3}=\tfrac{1}{2}$ model, additional mechanisms, such as
anisotropic exchange coupling, are required.",2112.05223v2
2021-12-30,Electrical manipulation of a hole `spin'-orbit qubit in nanowire quantum dot: the nontrivial magnetic field effects,"Strong `spin'-orbit coupled one-dimensional hole gas is achievable in a Ge
nanowire in the presence of a strong magnetic field. The strong magnetic field
lifts the two-fold degeneracy in the hole subband dispersions, so that the
effective low-energy subband dispersion exhibits strong `spin'-orbit coupling.
Here, we study the electrical `spin' manipulation in a Ge nanowire quantum dot
for both the lowest and second lowest hole subband dispersions. Using a finite
square well to model the quantum dot confining potential, we calculate exactly
the level splitting of the `spin'-orbit qubit and the Rabi frequency in the
electric-dipole `spin' resonance. The `spin'-orbit coupling modulated
longitudinal $g$-factor $g_{\rm so}$ is not only non-vanishing but also
magnetic field dependent. Moreover, the `spin'-orbit couplings of the lowest
and second lowest subband dispersions have opposite magnetic dependences, so
that the results for these two subband dispersions are totally different.",2112.14899v3
2022-01-14,An Anderson impurity interacting with the helical edge states in a quantum spin Hall insulator,"Using the natural orbitals renormalization group (NORG) method, we have
investigated the screening of the local spin of an Anderson impurity
interacting with the helical edge states in a quantum spin Hall insulator. We
find that there is a local spin formed at the impurity site and the local spin
is completely screened by electrons in the quantum spin Hall insulator.
Meanwhile, the local spin is screened dominantly by a single active natural
orbital. We then show that the Kondo screening mechanism becomes transparent
and simple in the framework of natural orbitals formalism. We project the
active natural orbital respectively into real space and momentum space to
characterize its structure. And we confirm the spin-momentum locking property
of the edge states based on the occupancy of a Bloch state in the edge to which
the impurity couples. Furthermore, we study the dynamical property of the
active natural orbital represented by the local density of states, from which
we observe the Kondo resonance peak.",2201.05308v1
2022-01-27,Effect of vertex corrections on the enhancement of Gilbert damping in spin pumping into a two-dimensional electron gas,"We theoretically consider the effect of vertex correction on spin pumping
from a ferromagnetic insulator (FI) into a two-dimensional electron gas (2DEG)
in which the Rashba and Dresselhaus spin-orbit interactions coexist. The
Gilbert damping in the FI is enhanced by elastic spin-flipping or magnon
absorption. We show that the Gilbert damping due to elastic spin-flipping is
strongly enhanced by the vertex correction when the ratio of the two spin-orbit
interactions is near a special value at which the spin relaxation time diverges
while that due to magnon absorption shows only small modification. We also show
that the shift in the resonant frequency due to elastic spin-flipping is
strongly enhanced in a similar way as the Gilbert damping.",2201.11498v3
2022-03-09,Mapping single electron spins with magnetic tomography,"Mapping the positions of single electron spins is a highly desired capability
for applications such as nanoscale magnetic resonance imaging and quantum
network characterization. Here, we demonstrate a method based on rotating an
external magnetic field to identify the precise location of single electron
spins in the vicinity of a quantum spin sensor. We use a nitrogen-vacancy
center in diamond as a quantum sensor and modulate the dipolar coupling to a
proximate electron spin in the crystal by varying the magnetic field vector.
The modulation of the dipolar coupling contains information on the coordinates
of the spin, from which we extract its position with an uncertainty of
0.9\,\AA. We show that the method can be used to locate electron spins with
nanometer precision up to 10\,nm away from the sensor. We discuss the method's
applicability to mapping hyperfine coupled electron spins, and show it may be
applied to locating nitroxide radicals. The magnetic tomography method can be
utilized for distance measurements for studying the structure of individual
molecules.",2203.04892v2
2022-08-20,Unravelling the contributions to spin-lattice relaxation in Kramers single-molecule magnets,"The study of how spin interacts with lattice vibrations and relaxes to
equilibrium provides unique insights on its chemical environment and the
relation between electronic structure and molecular composition. Despite its
importance for several disciplines, ranging from magnetic resonance to quantum
technologies, a convincing interpretation of spin dynamics in crystals of
magnetic molecules is still lacking due to the challenging experimental
determination of the correct spin relaxation mechanism. We apply ab initio spin
dynamics to a series of twelve coordination complexes of Co(II) and Dy(III)
ions selected among $\sim$240 compounds that largely cover the literature on
single-molecule magnets and well represent different regimes of spin
relaxation. Simulations reveal that the Orbach spin relaxation rate of known
compounds mostly depends on the ions' zero-field splitting and little on the
details of molecular vibrations. Raman relaxation is instead found to be also
significantly affected by the features of low-energy phonons. These results
provide a complete understanding of the factors limiting spin lifetime in
single-molecule magnets and revisit years of experimental investigations by
making it possible to transparently distinguish Orbach and Raman relaxation
mechanisms.",2208.09674v1
2022-08-24,Room-temperature coherent optical manipulation of single-hole spins in solution-grown perovskite quantum dots,"Manipulation of solid-state spin coherence is an important paradigm for
quantum information processing. Current systems either operate at very low
temperatures or are difficult to scale-up. Developing low-cost, scalable
materials whose spins can be coherently manipulated at room temperature is thus
highly-attractive for a sustainable future of quantum information science. Here
we report ambient-condition all-optical initialization, manipulation and
readout of single-hole spins in an ensemble of solution-grown CsPbBr3
perovskite QDs. Single-hole spins are obtained by sub-picosecond electron
scavenging following a circularly-polarized femtosecond-pulse excitation. A
transversal magnetic field induces spin precession, and a second off-resonance
femtosecond-pulse coherently rotates hole spins via strong light-matter
interaction. These operations accomplish nearly complete quantum-state control
of single-hole spins at room temperature.",2208.11614v1
2022-10-30,Using parity-nonconserving spin-spin coupling to measure the Tl nuclear anapole moment in a TlF molecular beam,"An experiment utilizing a TlF molecular beam is being developed by the
CeNTREX collaboration to search for hadronic interactions that violate both
time-reversal (T) and parity (P) invariance. Here we propose to use the same
beam to look for a T-invariance conserving but P-nonconserving (PNC) effect
induced by the anapole moment of the Tl nucleus, via a vector coupling of the
two nuclear spins in TlF. To measure the nuclear anapole moment, the dc
electric and magnetic fields in CeNTREX are replaced by rf fields resonant with
a nuclear spin flip transition. We adapt the relativistic coupled cluster
method in a combination with relativistic density functional theory for the
calculation of the molecular PNC spin-spin vector coupling constant that links
the experimental signal with the anapole moment. The value of the P-conserving
spin-spin coupling constant calculated within the same approach is found to be
in good agreement with available experimental data.",2210.16910v2
2022-12-07,Mechanism of Spin Scattering in Ta investigated by Scanning Inverse Spin Hall Effect Meters,"In this work, a scanning inverse spin Hall effect measurement system based on
a shorted coaxial resonator has been built, which provides a high throughput
method to characterize spin transport properties. The spin diffusion length of
Ta at room temperature is determined via automatic measurements of Py/Ta
bilayer strips with different thicknesses of Ta. The results show that the spin
diffusion length is about 4 nm with a conductivity of about 7.5E5
{\Omega}-1m-1, which leads to the conclusion that the intrinsic mechanism of
spin relaxation of Ta is the Elliott-Yafet interactions. The setup developed in
this work provides a convenient, efficient, and non-destructive way to obtain
the spin and electron transportation characteristics of the spintronic
materials, which will fertilize this community by developing new materials and
figuring out their mechanism.",2212.03556v1
2023-04-21,Theory of absorption in a frustrated spin gap system ${\rm SrCu_2(BO_3)_2}$,"We achieve a comprehensive understanding of the magnetic excitations observed
by electric spin resonance and far-infrared spectroscopy in a frustrated spin
gap system ${\rm SrCu_2(BO_3)_2}$ by considering the effects of magnetoelectric
couplings and Dzyaloshinskii-Moriya interactions in the Shastry-Sutherland
model. The transitions from the dimer singlet ground state to the triplon and
the bound states of two triplons are electroactive through the magnetoelectric
couplings, even in the Shastry-Sutherland Heisenberg model. The results
indicate that an electro-triplon and a novel electroactive magnetic excitation,
as with an electromagnon in the multiferroics, can be realized in the
conventional spin-gapped singlet and anomalous spin-liquid states. Clarifying
these electroactive magnetic excitations in various spin systems will help
analyze a broad range of quantum magnets, {\it e.g.}, quantum spin liquids and
spin nematics.",2304.10823v1
2023-05-10,Collisionless dynamics of superconducting gap excited by spin-splitting field,"We study the coherent dynamic interaction of a time-dependent spin-splitting
field with the homogeneous superconducting order parameter $\Delta(t)$ mediated
by spin-orbit coupling using the time-dependent Bogoliubov-de Gennes theory. In
the first part of the work we show that linear response of the superconductor
is strongly affected by the Zeeman field and spin-flip processes, giving rise
to multiple resonant frequencies of the superconducting Higgs modes. These
modes can be excited either by a quench, or by an additional non-stationary
component of the spin-splitting field, which couples linearly to the Higgs
modes. In the second part, we analyze the nonadiabatic dynamics of
quasiparticle states arising from the intersection of spectral branches from
different spin subbands, which can be provoked by a linearly growing Zeeman
field. We provide insights into the dependence of the order parameter
$\Delta(t)$ on this field and interference effects caused by tunneling of
states at the avoided crossing points. We also show that since the nonadiabatic
tunneling is related to spin-flip processes, the quasiparticle gas experiences
a dynamic magnetization that contributes to its spin susceptibility.",2305.06201v1
2023-05-16,Antiferromagnetic spin fluctuations and unconventional superconductivity in topological superconductor candidate YPtBi revealed by $^{195}$Pt-NMR,"We report $^{195}$Pt nuclear magnetic resonance (NMR) measurements on
topological superconductor candidate YPtBi which has the broken inversion
symmetry and topological non-trivial band structures due to the strong
spin-orbit coupling(SOC). In the normal state, we find that Knight shift $K$ is
field- and temperature-independent, suggesting that the contribution from the
topological bands is very small at low temperatures. However, the spin-lattice
relaxation rate 1/$T_1$ divided by temperature ($T$), 1/$T_1T$, increases with
decreasing $T$, implying the existence of antiferromagnetic spin fluctuations.
In the superconducting state, no Hebel-Slichter coherence peak is seen below
$T_{\rm c}$ and 1/$T_1$ follows $T^{3}$ variation, indicating the
unconventional superconductivity. The finite spin susceptibility at
zero-temperature limit and the anomalous increase of the NMR line width below
$T_{\rm c}$ point to a mixed state of spin-singlet and spin-triplet(or
spin-septet) pairing.",2305.09437v1
2023-05-23,Theory of inverse Rashba-Edelstein effect induced by spin pumping into a two-dimensional electron gas,"The inverse Rashba-Edelstein effect (IREE) in a two-dimensional electron gas
(2DEG) induced by spin pumping from an adjacent ferromagnetic insulator (FI) is
investigated theoretically. In particular, spin and current densities in the
2DEG in which both Rashba and Dresselhaus spin-orbit interactions coexist are
formulated, and their dependencies on ferromagnetic resonance frequency and
orientation of the spin in the FI are clarified. It is shown that spin density
diverges when the ratio between the Rashba and Dresselhaus spin-orbit
interactions approaches unity, while current density stays finite there. These
results can be applied for evaluating spin splitting on the Fermi surface in a
2DEG and designing spintronic devices using IREE.",2305.13953v3
2023-07-24,Super narrow peaks in excitation spectrum of alkali spin polarization: non-adiabatic case of spin dynamics,"We theoretically describe the phenomenon of non-adiabatic spin dynamics,
which occurs in a gas cell filled by alkali vapor in presence of a strong
alternating magnetic field and pump light. Steep increase of the spin
polarization occurs if frequency of the magnetic field is equal to the certain
value. Although, the observable effect relies on the periodic field that
consists of two perpendicular components defined by harmonics with the same
amplitudes and different frequencies. Considered spin effect cannot be
explained by a resonance, because the own Larmor frequency of spin precession
is absent without a constant component of magnetic field. Moreover, there are
some clearly visible peaks in the excitation spectrum of spin polarization, and
they are super narrow in comparison to relaxation rate. Detailed analysis
according to proposed quantum model results in the reasoning of the effect via
qualitative properties of non-adiabatic dynamics of atomic spin.",2307.12647v2
2023-08-22,Observation of Current-induced Nonlinear Spin Polarization in Pt-Py Bilayers,"We experimentally observe nonlinear spin polarization in metallic bilayers of
platinum and permalloy by means of spin-torque ferromagnetic resonance (ST-FMR)
with the spin-Hall effects. The ST-FMR results under massive dc current
injection contain striking features, which are not caused by extrinsic Joule
heating, but by intrinsic nonlinear spin polarization. The emergence of
nonlinear spin polarization is consistent with observation of unidirectional
spin-Hall magnetoresistance due to magnon generation/annihilation. Moreover,
the magnon generation (annihilation) leads to effective magnetization shrinkage
(expansion) revealed by the ST-FMR measurements. The present study paves a way
to spin-Hall effect based nonlinear spintronic devices as well as
6th-generation mobile communication light sources.",2308.11156v2
2023-09-25,Fast coherent control of nitrogen-14 spins associated with nitrogen-vacancy centers in diamonds using dynamical decoupling,"A nitrogen-vacancy (NV) center in a diamond enables the access to an electron
spin, which is expected to present highly sensitive quantum sensors. Although
exploiting a nitrogen nuclear spin improves the sensitivity, manipulating it
using a resonant pulse requires a long gate time owing to its small
gyromagnetic ratio. Another technique to control nuclear spins is a conditional
rotation gate based on dynamical decoupling, which is faster but unavailable
for nitrogen spins owing to the lack of transverse hyperfine coupling with the
electron spin. In this study, we generated effective transverse coupling by
applying a weak off-axis magnetic field. An effective coupling depends on the
off-axis field; the conditional rotation gate on the nitrogen-14 spins of an NV
center was demonstrated within 4.2 {\mu}s under an 1.8% off-axis field and a
longitudinal field of approximately 280 mT. We estimated that a population
transfer from the electron to nitrogen spins can be implemented with 8.7
{\mu}s. Our method is applicable to an ensemble of NV centers, in addition to a
single NV center.",2309.14278v1
2023-09-27,Direct Sensing of Remote Nuclei: Expanding the Reach of Cross-Effect Dynamic Nuclear Polarization,"Dynamic Nuclear Polarization (DNP) has revolutionized the field of
solid-state NMR spectroscopy by significantly enhancing the sensitivity of
nuclear magnetic resonance experiments. Conventionally, cross effect DNP relies
on biradicals to transfer polarization from coupled electron spins to nearby
nuclear spins and subsequent relay to target nuclei via spin diffusion
mechanism. However, the direct transfer of polarization to distant nuclei
remains a significant challenge, limiting its applicability in various
contexts. In this work, we propose a novel biradical design concept that
involves a very strong electron-electron coupling, with a magnitude of hundreds
of MHz, which enables efficient direct polarization transfer from electron
spins to nuclear spins over much longer distances, exceeding 2.0 nm. We discuss
the potential of this tailored biradicals in scenarios where conventional spin
diffusion mechanisms are inefficient or when direct nuclear spin sensing
through electron spin interactions is desired. Our study presents a promising
avenue for expanding the scope of cross effect DNP in solid-state NMR
spectroscopy and opens new opportunities for investigating a wide range of
biological and material systems. Our research also provides insight into the
DNP buildup time of commercially available biradicals.",2309.15653v1
2023-10-16,Generation and detection of spin current in iridate/manganite heterostructures,"The present study focuses on experimental investigations of spin current
across the interface of an iridate/manganite heterostructure
(SrIrO3/La0.7Sr0.3MnO3) consisting of oxide epitaxial films with nanometer
thickness. Pure spin current is induced by microwave irradiation in the GHz
frequency band, specifically under conditions of ferromagnetic resonance. The
detection of spin current is achieved through the inverse spin-Hall effect,
which measures the charge current arising on the electrically conductive SrIrO3
film with strong spin-orbit interaction. To quantify the efficiency of spin
current conversion to charge current, the angular dependences of spin
magnetoresistance of the iridate/manganite interface are measured, thereby
determining the spin- Hall angle.",2310.10297v1
2023-10-17,Direct measurement of spin-flip rates in single-electron tunneling,"Spin-flips are one of the limiting factors for spin-based information
processing. We demonstrate a transport approach for determining the spin-flip
rates of a self-assembled InAs double quantum dot occupied by a single
electron. In such devices, different Land\'e factors lead to an inhomogeneous
Zeeman splitting, so that the two spin channels can never be at resonance
simultaneously, leading to a spin blockade at low temperatures. This blockade
is analyzed in terms of spin flips for different temperatures and magnetic
fields. Our results are in good agreement with a quantum master equation that
combines the dot-lead couplings with ohmic dissipation stemming from spin-flip
cotunneling.",2310.11259v2
2023-10-18,Chiral spin textures creation and dynamics in a rectangular nanostructure,"Controlled creation of stable chiral spin textures is required to use them as
an energy-efficient information carrier in spintronics. Here we have studied
the stable creation of isolated chiral spin texture (skyrmion and antiskyrmion)
and its pair through the magnetization reversal of a rectangular nanostructure
using spin-polarized currents. An isolated spin texture is created through a
negative current pulse. Dynamics of the stable spin texture are explored under
external magnetic fields, and the resonant frequencies are calculated. A stable
skyrmion pair is created using an asymmetric current pulse, and their
interaction is studied using the Thiele equation. The stability of isolated or
paired spin texture depends on the DMI strength, spin-polarized current
density, and pulse duration. In addition, the stability of the skyrmion pair
depends on their initial separation, and a threshold for the separation between
skyrmions of 78 nm is observed.",2310.12129v1
2023-12-21,Generation of femtosecond spin-polarized current pulses at Fe/MgO interface by quasi-static voltage,"The generation of short spin-current pulses is essential for fast spintronic
devices. So far, spin current pulses are generated by femtosecond laser pulses
which drive spins from a ferromagnetic metal layer. However, the need for
miniaturization, simplicity and energy efficiency favour electric-field control
of spintronic devices over optic or thermal control. Here, we combine ab initio
calculations of electronic density of states at MgO/Fe interface with
continuous model for charge transport to investigate the dynamics of the
spin-dependent potential. We demonstrate that the voltage-driven instability of
the electronic band structure due to the electronic resonant states at the
Fe/MgO interface results in the generation of the femtosecond spin-polarized
current pulse with the spin polarization up to P=700% that propagates from the
interface to the bulk. The dynamics of the current pulses driven by the Stoner
instability depends neither on the dielectric relaxation time nor on the
details of how the instability is achieved by changing the voltage, i.e. as
long as the voltage changes are slow (quasi-static) with respect to the time
determined by the spin diffusion constant, being of the order of fs.The
presence of the instability may be detected by transport or magnetic
measurements.",2312.13698v1
2023-12-29,Quantum-grade nanodiamonds for ultrabright spin detection in live cells,"Optically accessible spin-active nanomaterials are promising as quantum
nanosensors for probing biological samples. However, achieving bioimaging-level
brightness and high-quality spin properties for these materials is challenging
and hinders their application in quantum biosensing. Here, we demonstrate
ultrabright fluorescent nanodiamonds (NDs) containing 0.6-1.3-ppm
nitrogen-vacancy (NV) centers by spin-environment engineering via enriching
spin-less 12C-carbon isotopes and reducing substitutional nitrogen spin
impurities. The NDs, readily introduced into cultured cells, exhibited
substantially narrow optically detected magnetic resonance (ODMR) spectra,
requiring 16-times less microwave excitation power to give an ODMR depth
comparable to that of conventional type-Ib NDs. They show average
spin-relaxation times of T1 = 0.68 ms and T_2 = 1.6 us (1.6 ms and 2.7 us
maximum) that were 5- and 11-fold longer than those of type-Ib, respectively.
The bulk-like NV spin properties and bright fluorescence demonstrated in this
study significantly improve the sensitivity of ND-based quantum sensors for
biological applications.",2312.17603v2
2024-01-10,Narrowly avoided spin-nematic phase in BaCdVO(PO$_4$)$_2$: NMR evidence,"We present a $^{31}$P nuclear magnetic resonance (NMR) investigation of
BaCdVO(PO$_4$)$_2$ focusing on the nearly saturated regime between
$\mu_0H_{c1}$ = 4.05 T and $\mu_0H_{c2}$ = 6.5 T, used to be considered as a
promising candidate for a spin-nematic phase. NMR spectra establish the absence
of any dipolar order there, whereas the weak field dependence of the
magnetization above $H_{c1}$ is accounted for by Dzyaloshinskii-Moriya
interaction terms. The low-energy spin dynamics (fluctuations), measured by
nuclear spin-lattice relaxation rate ($T_1^{-1}$), confirms the continuity of
this phase and the absence of any low-temperature phase transition.
Unexpectedly, the spin dynamics above $H_{c1}$ is largely dominated by
two-magnon processes, which is expected above the saturation field of a
spin-nematic phase, but not inside. This shows that BaCdVO(PO$_4$)$_2$ is
indeed close to a spin-nematic instability, however, this phase is not
stabilized. We thus confirm recent theoretical predictions that the
spin-nematic phase can be stabilized, at most, in an extremely narrow field
range close to saturation or is rather narrowly avoided [Jiang et al., Phys.
Rev. Lett. 130, 116701 (2023)].",2401.05269v1
2024-03-04,Multidimensional spectroscopy of nuclear spin clusters in diamond,"Optically active spin defects in solids offer promising platforms to
investigate nuclear spin clusters with high sensitivity and atomic-site
resolution. To leverage near-surface defects for molecular structure analysis
in chemical and biological contexts using nuclear magnetic resonance (NMR),
further advances in spectroscopic characterization of nuclear environments are
essential. Here, we report Fourier spectroscopy techniques to improve
localization and mapping of the testbed $^{13}\mathrm{C}$ nuclear spin
environment of individual, shallow nitrogen-vacancy centers at room
temperature. We use multidimensional spectroscopy, well-known from classical
NMR, in combination with weak measurements of single-nuclear-spin precession.
We demonstrate two examples of multidimensional NMR: (i) improved nuclear spin
localization by separate encoding of the two hyperfine components along
spectral dimensions and (ii) spectral editing of nuclear-spin pairs, including
measurement of internuclear coupling constants. Our work adds important tools
for the spectroscopic analysis of molecular structures by single-spin probes.",2403.02114v1
2024-03-21,Realizing topological quantum magnets with atomic spins on surfaces,"Artificial quantum systems have emerged as indispensable platforms to realize
exotic topological matter in a well-controlled manner. Here, we demonstrate
topological quantum Heisenberg spin lattices, engineered with spin chains and
two-dimensional spin arrays using spin 1/2 atoms on insulating films in a
scanning tunnelling microscope (STM). We engineered with atomic precision both
topological and trivial phases of the quantum spin model, realizing first- and
second-order topological quantum magnets. Their many-body excitations were
probed by single-atom electron spin resonance with ultrahigh energy resolution.
The atomically-localized magnetic field of the STM tip allows us to directly
visualize various topological bound modes including topological edge states,
topological defects, and higher-order corner modes. Our results provide an
important bottom-up approach to simulating exotic quantum many-body phases of
interacting spins.",2403.14145v1
2024-03-26,Nuclear spin-spin interactions in CdTe probed by zero and ultra-low-field optically detected NMR,"Nuclear magnetic resonance (NMR) is particularly relevant for studies of
internuclear spin coupling at zero and ultra-low fields (ZULF), where spin-spin
interactions dominate over Zeeman ones. Here we report on ZULF NMR in CdTe. In
this semiconductor all magnetic isotopes have spin $I = 1/2$, so that
internuclear interactions are never overshadowed by quadrupole effects. Our
experiments rely on warm-up spectroscopy, a technique that combines optical
pumping, additional cooling via adiabatic demagnetisation, and detection of the
oscillating magnetic field-induced warm-up of the nuclear spin system via Hanle
effect. We show that NMR spectra exhibit a rich fine structure, consistent with
the low abundance of magnetic isotopes in CdTe, their zero quadrupole moments,
as well as direct and indirect interactions between them. A model assuming that
the electromagnetic radiation is absorbed by nuclear spin clusters composed of
up to 5 magnetic isotopes allows us to reproduce the shape of a major part of
the measured spectra.",2403.17593v1
2024-04-11,Dynamical Reorientation of Spin Multipoles in Silicon Carbide by Transverse Magnetic Fields,"The long-lived and optically addressable high-spin state of the negatively
charged silicon vacancy ($\mathrm{V_{Si}}$) in silicon carbide makes it a
promising system for applications in quantum technologies. Most studies of its
spin dynamics have been performed in external magnetic fields applied along the
symmetry axis. Here, we find that the application of weak magnetic fields
perpendicular to the symmetry axis leads to nontrivial behavior caused by
dynamical reorientation of the $\mathrm{V_{Si}}$ spin multipole under optical
excitation. Particularly, we observe the inversion of the quadrupole spin
polarization in the excited state and appearance of the dipole spin
polarization in the ground state. The latter is much higher than thermal
polarization and cannot be induced solely by optical excitation. Our
theoretical calculations reproduce well all sharp features in the spin
resonance spectra, and shine light on the complex dynamics of spin multipoles
in these kinds of solid-state systems.",2404.07915v1
2020-03-14,Enhanced longevity of the spin helix in low-symmetry quantum wells,"In a semiconductor, collective excitations of spin textures usually decay
rather fast due to D'yakonov-Perel' spin relaxation. The latter arises from
spin-orbit coupling, which induces wave-vector-dependent spin rotations that,
in conjunction with random disorder scattering, generate spin decoherence.
However, symmetries occurring under certain conditions can prevent the
relaxation of particular homogeneous and inhomogeneous spin textures. The
inhomogeneous spin texture, termed as persistent spin helix, is especially
appealing as it enables us to manipulate the spin orientation while retaining a
long spin lifetime. Recently, it was predicted that such symmetries can be
realized in zinc-blende two-dimensional electron gases if at least two
growth-direction Miller indices agree in modulus and the coefficients of the
Rashba and linear Dresselhaus spin-orbit couplings are suitably matched [PRL
117, 236801 (2016)]. In the present paper, we systematically analyze the impact
of the symmetry-breaking cubic Dresselhaus spin-orbit coupling, which
generically coexists in these systems, on the stability of the emerging spin
helices with respect to the growth direction. We find that, as an interplay
between orientation and strength of the effective magnetic field induced by the
cubic Dresselhaus terms, the spin relaxation is weakest for a low-symmetry
growth direction that can be well approximated by a [225] lattice vector. These
quantum wells yield a 30\% spin-helix lifetime enhancement compared to
[001]-oriented electron gases and, remarkably, require a negligible Rashba
coefficient. The rotation axis of the corresponding spin helix is only slightly
tilted out of the quantum-well plane. This makes the experimental study of the
spin-helix dynamics readily accessible for conventional optical spin
orientation measurements where spins are excited and detected along the
quantum-well growth direction.",2003.06544v2
2020-01-17,Thermal spin transport and spin in thermoelectrics,"This article reviews the principles that govern the combined transport of
spin, heat, and charge. The extensive thermodynamic quantity associated with
spin transport is the magnetization; its Onsager-conjugate force is in general
the derivative of the free energy with respect to the magnetization. Spins are
carried in one of two ways: (1) by spin-polarized free electrons in magnetic
metals and doped semiconductors, or (2) by spin waves (magnons) that reside on
localized electrons on unfilled d- or f-shells of transition metal or
rare-earth elements. The paper covers both cases in separate chapters. In both
cases, it is possible to define a spin chemical potential whose gradient is the
more practical conjugate force to spin transport. The paper further describes
the anomalous Hall, spin Hall, and inverse spin Hall effects in magnetic and
non-magnetic solids with strong spin-orbit coupling because these effects are
used to generate and measure spin fluxes. Spin transport across interfaces is
described next, and includes spin pumping and spin transfer torque. The final
chapter then puts all these concepts together to describe the spin-Seebeck,
spin-Peltier, and magnon-drag effects, which exist in ferromagnetic,
antiferromagnetic, and even paramagnetic solids. Magnon-drag, in particular, is
a high-temperature effect that boosts the thermopower of metals by an order of
magnitude and that of semiconductors by a factor of 2 or 3 above the electronic
diffusion thermopower. This is the only example where a spin-driven effect is
larger than a charge-driven effect. Magnon drag leads a simple binary
paramagnetic semiconductor, MnTe, to have zT > 1 without optimization. This
shows how adding spin as an additional design parameter in thermoelectrics
research is a new and promising approach toward the quest for high-zT
materials.",2001.06366v1
1996-07-11,Exact results for resonating valence bonds states on 2D (narrow) systems,"It is shown that the problem of calculating spin-spin correlation functions,
in the dimers RVB states, on a possibly diluted 2D square lattice, can be
formulated in terms of a transfer matrix. The transfer matrix is used for exact
numerical calculations of spin-spin correlation functions on ladders up to four
units wide.",9607076v2
1997-10-29,Relaxation Regimes of Spin Maser,"Spin relaxation in a microscopic model of spin maser is studied
theoretically. Seven qualitatively different regimes are found: free induction,
collective induction, free relaxation, collective relaxation, weak
superradiance, pure superradiance, and triggered superradiance. The initiation
of relaxation can be originated either by an imposed initial coherence or by
local spin fluctuations due to nonsecular dipole interactions. The Nyquist
noise of resonator does not influence processes in macroscopic samples. The
relaxation regimes not initiated by an imposed coherence cannot be described by
the standard Bloch equations.",9710311v1
1999-05-18,Spin-orbit scattering in d-wave superconductors,"When non-magnetic impurities are introduced in a d-wave superconductor, both
thermodynamic and spectral properties are strongly affected if the impurity
potential is close to the strong resonance limit. In addition to the scalar
impurity potential, the charge carriers are also spin-orbit coupled to the
impurities. Here it is shown that (i) close to the unitarity limit for the
impurity scattering, the spin-orbit contribution is of the same order of
magnitude than the scalar scattering and cannot be neglected, (ii) the
spin-orbit scattering is pair-breaking and (iii) induces a small id_xy
component to the off-diagonal part of the self-energy.",9905262v1
2000-01-10,SIN and SIS tunneling in cuprates,"We calculate the SIN and SIS tunneling conductances for the spin-fermion
model. We argue that at strong spin-fermion coupling, relevant to cuprates,
both conductances have dip features near the threshold frequencies when a
tunneling electron begin emitting propagating spin excitation. We argue that
the resonance spin frequency measured in neutron scattering can be inferred
from the tunneling data by analyzing the derivatives of SIN and SIS
conductances.",0001125v1
2000-09-21,Dynamics of spin correlations in the spin-1/2 isotropic XY chain in a transverse field,"Dynamic xx spin pair correlation functions for the isotropic spin-1/2 XY
chain are calculated numerically for long open chains in the presence of a
transverse magnetic field at finite temperature. As an application we discuss
the temperature dependence of the spin-spin relaxation time in PrCl_3.",0009334v1
2000-10-10,Optical manipulation of nuclear spin by a two-dimensional electron gas,"Conduction electrons are used to optically polarize, detect and manipulate
nuclear spin in a (110) GaAs quantum well. Using optical Larmor magnetometry,
we find that nuclear spin can be polarized along or against the applied
magnetic field, depending on field polarity and tilting of the sample with
respect to the optical pump beam. Periodic optical excitation of the
quantum-confined electron spin reveals a complete spectrum of optically-induced
and quadrupolar-split nuclear resonances, as well as evidence for delta m = 2
transitions.",0010139v1
2001-07-10,Spin Dynamics near the Superconductor-to-Insulator Transition in Impurity-Doped YBa2Cu4O8,"We studied low-frequency spin dynamics near the impurity-induced
superconductor-to-insulator transition for underdoped high-Tc superconductor
YBa2(Cu1-xMx)4O8 (M=Ni, Zn) using the Cu nuclear quadrupole resonance (NQR)
spin-echo technique. We observed remarkable suppression of the normal-state
pseudo spin-gap and a loss of Cu NQR spectrum intensity at low temperatures
around the critical impurity concentration.",0107187v1
2002-10-02,Local Magnetic Susceptibility of the Positive Muon in the Quasi 1D S=1/2 Antiferromagnet KCuF$_3$,"We report muon spin rotation measurements of the local magnetic
susceptibility around a positive muon in the paramagnetic state of the quasi
one-dimensional spin 1/2 antiferromagnet KCuF$_3$. Signals from two distinct
sites are resolved which have a temperature dependent frequency shift which is
different than the magnetic susceptibility. This difference is attributed to a
muon induced perturbation of the spin 1/2 chain.",0210060v1
2002-11-13,Test for Pairing Symmetry Based on Spin Fluctuations in Organic Superconductors $κ$-(BEDT-TTF)$_{2}$X,"We propose that the superconducting pairing symmetry of organic
superconductors $\kappa$-(BEDT-TTF)$_{2}$X can be determined by measuring the
position in momentum space of the incommensurate peaks of the spin
susceptibility. We show that the positions of these peaks are uniquely
determined by the symmetry of the superconducting state and the geometry of
Fermi surface. Based on the effective Hubbard model on an anisotropic
triangular lattice, we demonstrate the different incommensurate patters of spin
responses for $d_{x^{2}-y^{2}}$- and $d_{xy}$-like pairing states. In addition,
we predict the nonexistence of the spin resonance mode in this compound, which
is an important feature in high-$T_{c}$ superconductors.",0211256v1
2003-02-17,Theory of spin density profile in the magnetization plateaus of SrCu_2(BO_3)_2,"The two-dimensional spin-gap system ${\rm SrCu_2(BO_3)_2}$ shows unique
physical properties due to the low-dimensionality character and the strong
quantum fluctuations. Experimentally, 1/8-, 1/4-, and 1/3-plateaus have been
observed in the magnetization curve under magnetic fields up to 70 Tesla, and
the 1/2-plateau is expected to be stabilized at higher magnetic fields. We
argue that spin-lattice effects are necessary to describe the superstructures
at the plateaus, and we propose a simple microscopic model of spins interacting
adiabatically with the lattice to reproduce the main features of the recent
experimental results by nuclear magnetic resonance.",0302332v1
2003-03-01,Electron Spin-Relaxation Times of Phosphorus Donors in Silicon,"Pulsed electron paramagnetic resonance measurements of donor electron spins
in natural phosphorus-doped silicon (Si:P) and isotopically-purified 28Si:P
show a strongly temperature-dependent longitudinal relaxation time, T1, due to
an Orbach process with DeltaE = 126 K. The 2-pulse echo decay is exponential in
28Si:P, with the transverse relaxation (decoherence) time, T2, controlled by
the Orbach process above ~12 K and by instantaneous diffusion at lower
temperatures. Spin echo experiments with varying pulse turning angles show that
the intrinsic T2 of an isolated spin in 28Si:P is ~60 ms at 7 K.",0303006v1
2003-05-23,A realization of Yangian and its applications to the bi-spin system,"Yangian $Y(sl(2))$ is realized in the bi-spin system coupled with a
time-dependent external magnetic field. It is shown that $Y(sl(2))$ generators
can describe the transitions between the ``spin triplet'' and the ``spin
singlet'' that evolve with time. Furthermore, new transition operators between
the states with Berry phase factor and those between the states of Nuclear
Magnetic Resonance (NMR) are presented.",0305550v1
2004-02-10,Spin-lattice NMR relaxation by anomalous translational diffusion,"A model-free theoretical framework for a phenomenological description of
spin-lattice relaxation by anomalous translational diffusion in inhomogeneous
systems based on the fractional diffusion equation is developed. The dependence
of the spin-lattice relaxation time on the size of the pores in porous glass
Vycor is experimentally obtained and found to agree well with our theoretical
predictions. We obtain nonmonotonic behavior of the translational spin-lattice
relaxation rate constant (it passes through a maximum) with the variation of
the parameter referring to the extent of inhomogeneity of the system.",0402274v2
2004-02-12,Impurity-induced tuning of quantum well states in spin-dependent resonant tunneling,"We report exact model calculations of the spin-dependent tunneling in double
magnetic tunnel junctions in the presence of impurities in the well. We show
that the impurity can tune selectively the spin channels giving rise to a wide
variety of interesting and novel transport phenomena. The tunneling
magnetoresistance, the spin polarization and the local current can be
dramatically enhanced or suppressed by impurities. The underlying mechanism is
the impurity-induced shift of the quantum well states (QWS) which depends on
the impurity potential, impurity position and the symmetry of the QWS.",0402324v1
2004-04-21,Spin state readout by quantum jump technique: for the purpose of quantum computing,"Utilizing the Pauli-blocking mechanism we show that shining circular
polarized light on a singly-charged quantum dot induces spin dependent
fluorescence. Employing the quantum-jump technique we demonstrate that this
resonance luminescence, due to a spin dependent optical excitation, serves as
an excellent readout mechanism for measuring the spin state of a single
electron confined to a quantum dot.",0404494v1
2004-04-24,Spin and Charge Pumping by Ferromagnetic-Superconductor Order Parameters,"We study transport in ferromagnetic-superconductor/normal-metal systems. It
is shown that charge and spin currents are pumped from ferromagnetic
superconductors into adjacent normal metals by adiabatic changes in the order
parameters induced by external electromagnetic fields. Spin and charge pumping
identify the symmetry of the superconducting order parameter, e.g., singlet
pairing or triplet pairing with opposite or equal spin pairing. Consequences
for ferromagnetic-resonance experiments are discussed.",0404591v2
2004-04-26,Spin filtering through a double-bend structure,"We propose a simple scheme for the spin filter by studying the coherent
transport of electrons through a double-bend structure in a quantum wire with a
weak lateral magnetic potential which is much weaker than the Fermi energy of
the leads. {\em Extremely large} spin polarized current in the order of {\em
micro-Ampere} can be obtained because of the strong resonant behavior from the
double bends. Further study suggests the roubustness of this spin filter.",0404605v1
2005-01-03,Electron Spin-Lattice Relaxation of doped Yb3+ ions in YBa2Cu3Ox,"The electron spin-lattice relaxation (SLR) times T1 of Yb3+&#135; ions were
measured from the temperature dependence of electron spin resonance linewidth
in Y0.99Yb0.01Ba2Cu3Ox with different oxygen contents. Raman relaxation
processes dominate the electron SLR. Derived from the temperature dependence of
the SLR rate, the Debye temperature (Td) increases with the critical
temperature Tc and oxygen content x. Keywords: EPR; ESR; Electron spin-lattice
relaxation; Debye temperature; Critical temperature",0501017v1
2005-11-28,Spin susceptibility of underdoped cuprates: the case of Ortho-II YBa_2Cu_3O_{6.5},"Recent inelastic neutron scattering measurements found that the spin
susceptibility of detwinned and highly ordered ortho-II YBa_2Cu_3O_{6.5}
exhibits, in both the normal and superconducting states, one-dimensional
incommensurate modulations at low energies which were interpreted as a
signature of dynamic stripes. We propose an alternative model based on
quasiparticle transitions between the arcs of a truncated Fermi surface. Such
transitions are resonantly enhanced by scattering to the triplet spin
resonance. We show that the anisotropy in the experimental spin response is
consistent with this model if the gap at the saddle points is anisotropic.",0511661v1
2006-01-13,Spin tunneling through an indirect barrier,"Spin-dependent tunneling through an indirect bandgap barrier like the
GaAs/AlAs/GaAs heterostructure along [001] direction is studied by the
tight-binding method. The tunneling is characterized by the proportionality of
the Dresselhaus Hamiltonians at $\Gamma $ and $X$ points in the barrier and by
Fano resonances. The present results suggest that large spin polarization can
be obtained for energy windows that exceed significantly the spin splitting. We
also formulate two conditions that are necessary for the existence of energy
windows with large polarization.",0601297v1
2006-03-27,Visualizing high-temperature spin dynamics in La1-xCaxMnO3 from a mapping of EPR linewidth and g factor,"This paper presents an analysis of electron paramagnetic resonance
parameters, i.e., g factor, linewidth, and intensity on powder samples of
La1-xCaxMnO3 at the commensurate carrier concentrations of x = N/8 (N = 1, 2,
3, 4, 5, 6, and 7). We demonstrate that the mapping of EPR parameters offers a
powerful tool to investigate high-temperature spin dynamics in the phase
diagram of colossal magnetoresistance (CMR) manganites. Our results convince
that the spin-spin relaxation mechanism should dominate the high-temperature
paramagnetic regime in CMR manganites.",0603705v2
2006-09-13,Nonlinear Rashba Model and Spin Relaxation in Quantum Wells,"We find that the Rashba spin splitting is intrinsically a nonlinear function
of the momentum, and the linear Rasha model may overestimate it significantly,
especially in narrow-gap materials. A nonlinear Rashba model is proposed, which
is in good agreement with the numerical results from the eight-band kp theory.
Using this model, we find pronounced suppression of the D'yakonov-Perel' spin
relaxation rate at large electron densities, and a non-monotonic dependence of
the resonance peak position of electron spin lifetime on the electron density
in [111]-oriented quantum wells, both in qualitative disagreement with the
predictions of the linear Rashba model.",0609311v1
2006-10-01,Odd-frequency pairing and Josephson effect at superconducting interfaces,"We demonstrate that, quite generally, the spin-singlet even-parity
(spin-triplet odd-parity) pair potential in a superconductor induces the
odd-frequency pairing component with spin-singlet odd-parity (spin-triplet
even-parity) near interfaces. The magnitude of the induced odd-frequency
component is enhanced in the presence of the midgap Andreev resonant state due
to the sign change of the anisotropic pair potential at the interface. The
Josephson effect should therefore occur between odd- and even-frequency
superconductors, contrary to the standard wisdom. A method to probe the
odd-frequency superconductors is proposed.",0610017v3
2007-02-09,Spin-dependent transport properties in GaMnAs-based spin hot-carrier transistors,"We have investigated the spin-dependent transport properties of GaMnAs-based
three-terminal semiconductor spin hot-carrier transistor (SSHCT) structures.
The emitter-base bias voltage VEB dependence of the collector current IC,
emitter current IE, and base current IB shows that the current transfer ratio
alpha (= IC / IE) and the current gain beta (= IC / IB) are 0.8-0.95 and 1-10,
respectively, which means that GaMnAs-based SSHCTs have current amplifiability.
In addition, we observed an oscillatory behavior of the tunneling
magnetoresistance (TMR) ratio with the increasing bias, which can be explained
by the resonant tunneling effect in the GaMnAs quantum well.",0702239v1
2003-06-27,New effects in neutrino oscillations in matter and electromagnetic fields,"Within the recently developed Lorentz invariant approach to neutrino spin and
flavour oscillations the following four new effects are discussed: 1) neutrino
spin oscillations in different electromagnetic field configurations, 2)
neutrino spin precession and oscillations stimulated by weak interaction with
background matter without presence of electromagnetic fields, 3) the
significant shift of neutrino spin and flavour oscillation resonances by matter
moving with relativistic speed, if compared with the case of non-moving matter,
4) the new mechanism of electromagnetic radiation by neutrino moving in
background matter and/or electromagnetic fields.",0306280v1
2001-05-25,Spin-vibrational 1+ states in 140Ce,"The properties of collective I^$\Pi$=1+ states in double even semimagic
nucleus 140Ce are investigated in random phase approximation(RPA). The
calculation of the B(M1) strength, elastic gamma-scattering cross section
$\sigma_(gamma)(\omega)$ and gamma-decay width $\Sigma_(gamma)(\omega_i)$ show
that in 140Ce the isovector spin-spin interactions concenrate the main strength
of M1 transition at energy 7.89 MeV where the isovector spin-flip magnetic
resonance may appear. The predisctions are consistent with the observed M1
strength in 140Ce which is seen to be concentrated within a range of about 0.8
MeV centered at an excitation of 7.95 MeV.",0105065v1
2003-06-18,Generation of Superposition Spin States in an Atomic Ensemble,"A method for generating a mesoscopic superposition state of the collective
spin variable of a gas of atoms is proposed. The state consists of a
superposition of the atomic spins pointing in two slightly different
directions. It is obtained by using off resonant light to carry out Quantum Non
Demolition Measurements of the spins. The relevant experimental conditions,
which require very dense atomic samples, can be realized with presently
available techniques. Long-lived atomic superposition states may become useful
as an off-line resource for quantum computing with otherwise linear operations.",0306121v1
2005-09-18,The ultra-sensitive electrical detection of spin Rabi oscillation at paramagnetic defects,"A short review of the pulsed electrically detected magnetic resonance (pEDMR)
experiment is presented. PEDMR allows the highly sensitive observation of
coherent electron spin motion of charge carriers and defects in semiconductors
by means of transient current measurements. The theoretical foundations, the
experimental implementation, its sensitivity and its potential with regard to
the investigation of electronic transitions in semiconductors are discussed.
For the example of the P_b center at the crystalline silicon (111) to silicon
dioxide interface it is shown experimentally how one can detect spin
Rabi-oscillation, its dephasing, coherence decays and spin-coupling effects.",0509120v1
2005-12-12,Fast polarimetry system for the application to spin quantum non-demolition measurement,"We report the development of a fast pulse polarimeter for the application to
quantum non-demolition measurement of atomic spin (Spin QND). The developed
system was tunable to the atomic resonance of ytterbium atom and has narrow
laser linewidth suitable for spin QND. Using the developed polarimeter, we
successfully demonstrated the measurement of the vacuum noise, with 10^6 to
10^7 photon number per pulse.",0512089v2
2007-07-13,Multiphoton antiresonance in large-spin systems,"We study nonlinear response of a spin $S>1/2$ with easy-axis anisotropy. The
response displays sharp dips or peaks when the modulation frequency is
adiabatically swept through multiphoton resonance. The effect is a consequence
of a special symmetry of the spin dynamics in a magnetic field for the
anisotropy energy $\propto S_z^2$. The occurrence of the dips or peaks is
determined by the spin state. Their shape strongly depends on the modulation
amplitude. Higher-order anisotropy breaks the symmetry, leading to sharp steps
in the response as function of frequency. The results bear on the dynamics of
molecular magnets in a static magnetic field.",0707.2107v1
2007-07-27,Leakage-induced decoherence during single electron spin manipulation in a double quantum dot,"Coherent single electron spin oscillation in a double quantum dot system
driven by a magnetic electron spin resonance field is studied theoretically
using a Bloch-type rate equation approach. The oscillation frequency and
relaxation time obtained using typical model parameters are consistent with
experiment findings. The dominant decoherence mechanism is identified to be a
leakage current through a Coulomb blockade barrier at a quantum dot during the
spin manipulation. Nuclear field fluctuations which induce a long relaxation
time are found to contribute only negligibly to the decoherence despite an
earlier suggestion.",0707.4040v1
2007-10-06,Spin Anisotropy in ZnCu_3(OH)_6Cl_2,"The spin anisotropic exchange interaction is suggested to contribute
significantly to the abnormal upturn of the magnetic susceptibility in the
ZnCu$_3$(OH)$_6$Cl$_2$. The saturation of the magnetic susceptibility below 300
mK observed in the muon spin resonance ($\mu$SR) experiment is the quantum
effect of the spin flipping process.",0710.1334v3
2007-11-26,Kondo Resonance in the Presence of Spin-Polarized Currents,"We propose an improved method of the equation of motion approach to study the
Kondo problem in spin-dependent non-equilibrium conditions. We find that the
previously introduced additional renormalization for non-equilibrium Kondo
effects is not required when we use a proper decoupling scheme. Our improved
formulation is then applied to address the spin-split Kondo peaks when a spin
current injects into a Kondo system.",0711.4121v1
2008-01-18,Selective Spin Injection Controlled by Electrical way in Ferromagnet/Quantum Dot/Semiconductor system,"Selective and large polarization of current injected into semiconductor (SC)
is predicted in Ferromagnet (FM)/Quantum Dot (QD)/SC system by varying the gate
voltage above the Kondo temperature. In addition, spin-dependent Kondo effect
is also revealed below Kondo temperature. It is found that Kondo resonances for
up spin state is suppressed with increasing of the polarization P of the FM
lead. While the down one is enhanced. The Kondo peak for up spin is disappear
at P=1.",0801.2922v1
2008-01-30,Enhanced thermal stability and spin-lattice relaxation rate of N@C60 inside carbon nanotubes,"We studied the temperature stability of the endohedral fullerene molecule,
N@C60, inside single-wall carbon nanotubes using electron spin resonance
spectroscopy. We found that the nitrogen escapes at higher temperatures in the
encapsulated material as compared to its pristine, crystalline form. The
temperature dependent spin-lattice relaxation time, T_1, of the encapsulated
molecule is significantly shorter than that of the crystalline material, which
is explained by the interaction of the nitrogen spin with the conduction
electrons of the nanotubes.",0801.4783v1
2008-07-15,Dynamics of dissipative coupled spins: decoherence and relaxation,"We study the reduced dynamics of interacting spins, each coupled to its own
bath of bosons. We derive the solution in analytic form in the white-noise
limit and analyze the rich behaviors in diverse limits ranging from weak
coupling and/or low temperature to strong coupling and/or high temperature. We
also view the one spin as being coupled to a spin-boson environment and
consider the regimes in which it is effectively nonlinear, and in which it can
be regarded as a resonant bosonic environment.",0807.2342v1
2008-10-24,Polarization and entanglement in spin systems,"We established important relationships between entanglement measures and the
order parameter (spin polarization) in nuclear spin systems controlled by the
nuclear magnetic resonance (NMR) technique. Since spin polarization can be
easily manipulated by the NMR technique, experimentalists are presented with an
opportunity to study the dynamic properties of entanglement, i.e., the creation
and evolution of entangled states. Our approach may constitute the basis for
researching the relations between the entanglement measures and measurable
parameters of order in other quantum systems.",0810.4388v1
2008-11-25,Theory of electric field induced one-magnon resonance in cycloidal spin magnets,"We propose a new mechanism to induce a novel one-magnon excitation by the
electric component of light in cycloidal spin states, i.e. so called
electromagnon process. We calculated optical spectra in the cycloidal spin
structures as observed in multiferroic perovskite manganites RMnO3 where novel
magnetic excitations induced by oscillating electric fields are observed. When
symmetric spin-dependent electric polarizations are introduced, we have light
absorptions at terahertz frequencies with one- and two-magnon excitations
driven by the electric component of light. Our results show that some parts of
optical spectra observed experimentally at terahertz frequencies are one-magnon
excitation absorptions.",0811.4082v1
2009-03-13,Spin-Exchange-Relaxation-Free Magnetometry Using Elliptically-Polarized Light,"Spin-exchange relaxation free alkali-metal magnetometers typically operate in
the regime of high optical density, presenting challenges for simple and
efficient optical pumping and detection. We describe a high-sensitivity Rb
magnetometer using a single elliptically-polarized off-resonant laser beam.
Circular component of the light creates relatively uniform spin polarization
while the linear component is used to measure optical rotation generated by the
atoms. Modulation of the atomic spin direction with an oscillating magnetic
field shifts the detected signal to high frequencies. Using a fiber-coupled DFB
laser we achieve magnetic field sensitivity of 7 fT/$\sqrt{% \mathrm{Hz}}$ with
a miniature $5\times5\times5$ mm Rb vapor cell.",0903.2447v1
2009-04-22,Current-induced nuclear-spin activation in a two-dimensional electron gas,"Electrically detected nuclear magnetic resonance was studied in detail in a
two-dimensional electron gas as a function of current bias and temperature. We
show that applying a relatively modest dc-current bias, I_dc ~ 0.5 microAmps,
can induce a re-entrant and even enhanced nuclear spin signal compared with the
signal obtained under similar thermal equilibrium conditions at zero current
bias. Our observations suggest that dynamic nuclear spin polarization by small
current flow is possible in a two-dimensional electron gas, allowing for easy
manipulation of the nuclear spin by simple switching of a dc current.",0904.3405v1
2009-05-08,Hyperfine tensors of nitrogen-vacancy center in diamond from \emph{ab initio} calculations,"We determine and analyze the charge and spin density distributions of
nitrogen-vacancy (N-V) center in diamond for both the ground and excited states
by \emph{ab initio} supercell calculations. We show that the hyperfine tensor
of $^{15}$N nuclear spin is negative and strongly anisotropic in the excited
state, in contrast to previous models used extensively to explain electron spin
resonance measurements. In addition, we detect a significant redistribution of
the spin density due to excitation that has serious implications for the
quantum register applications of N-V center.",0905.1169v1
2009-06-04,Quark-Hadron Duality in Neutron Spin-Structure and g_2 moments at intermediate Q**2,"Jefferson Lab experiment E01-012 measured the He-3 spin-structure functions
and virtual photon asymmetries in the resonance region in the momentum transfer
range 1.0<Q**2<4.0(GeV/c)**2. Our data, when compared with existing deep
inelastic scattering data, were used to test quark-hadron duality in g_1 and
A_1 for He-3 and the neutron. In addition, preliminary results on the He-3
spin-structure function g_2, on the Burkhardt-Cottingham sum rule and on higher
twist effects through the x**2-weighted moment d_2 of the neutron were
presented.",0906.0928v1
2009-09-15,The effective spin concept to analyze coherent charge transport in mesoscopic systems,"An effective spin concept is introduced to examine the mathematical and
physical analogy between phase coherent charge transport in mesoscopic systems
and quantum operations on spin based qubits. When coupled with the Bloch sphere
concept, this isomorphism allows formulation of transport problems in a
language more familiar to researchers in the field of spintronics and quantum
computing. We exemplify the synergy between charge tunneling and spin qubit
unitary operations by recasting well-known problems of tunneling through a
delta scatterer, a resonant tunneling structure, a superlattice structure, and
arrays of elastic scatterers, in terms of specific unitary operations
(rotations) of a spinor on the Bloch sphere.",0909.2892v1
2010-04-01,Phenomenological Model of Longitudinal Spin Fluctuations in Itinerant Antiferromagnets,"We present the phenomenological analysis of the spectrum of longitudinal spin
fluctuations in isotropic itinerant electron antiferromagnets with account of
spin anharmonicity giving rise to coupling of transverse and longitudinal
normal modes. The spectrum consists of a quasielastic part forming a central
peak or a dip, depending on temperature and the Landau relaxation rate. Effects
of spin fluctuation coupling also give rise to an inelastic part of the
spectrum which has a form of resonances or antiresonances near the magnon
frequencies related to non-propagating longitudinal excitations.",1004.0136v1
2010-05-17,QND Measurement of Large-Spin Ensembles by Dynamical Decoupling,"Quantum non-demolition (QND) measurement of collective variables by
off-resonant optical probing has the ability to create entanglement and
squeezing in atomic ensembles. Until now, this technique has been applied to
real or effective spin one-half systems. We show theoretically that the
build-up of Raman coherence prevents the naive application of this technique to
larger spin atoms, but that dynamical decoupling can be used to recover the
ideal QND behavior. We experimentally demonstrate dynamical decoupling by using
a two-polarization probing technique. The decoupled QND measurement achieves a
sensitivity 5.7(6) dB better than the spin projection noise.",1005.2807v1
2010-06-28,Eliashberg Analysis of Optical Spectra Reveals Strong Coupling of Charge Carriers to Spin Fluctuations in Superconducting Iron Pnictides,"The temperature and frequency dependences of the optical conductivity of Co
and Ni-doped BaFe2As2 are analyzed and the electron-boson spectral density
a2F(w) extracted using Eliashberg's formalism. The characteristic energy of a
large peak in the spectrum around 10 meV coincide with the resonance peak in
the spin excitation spectra, giving compelling evidence that in iron-based
superconductors spin fluctuations strongly couple to the charge carriers and
mediate superconductivity. In addition the spectrum is found to evolve with
temperature towards a less structured background at higher energies as in the
spin susceptibility.",1006.5468v1
2011-04-28,Spin and Orbital Characters of Excitations in Iron Arsenide Superconductors Revealed by Simulated Fe L-Edge RIXS,"We theoretically examine the orbital excitations coupled to the spin degree
of freedom in the parent state of the iron-arsenide superconductor, based on
the calculation in a five-band itinerant model. The calculated Fe $L_3$-edge
resonant inelastic x-ray scattering (RIXS) spectra disclose the presence of
spin-flip excitations involving several specific orbitals. Magnon excitations
predominantly composed of a single orbital component can be seen in
experiments, although its spectral weight is smaller than spin-flipped
interorbital high-energy excitations. The detailed polarization and momentum
dependence is also discussed with predictions for the experiments.",1104.5424v2
2011-07-04,Minimization of the Switching Time of a Synthetic Free Layer in Thermally Assisted Spin Torque Switching,"We theoretically studied the thermally assisted spin torque switching of a
synthetic free layer and showed that the switching time is minimized if the
condition H_J=|H_s|/(2 alpha) is satisfied, where H_J, H_s and alpha are the
coupling field of two ferromagnetic layers, the amplitude of the spin torque,
and the Gilbert damping constant. We also showed that the coupling field of the
synthetic free layer can be determined from the resonance frequencies of the
spin-torque diode effect.",1107.0753v2
2011-07-14,Coherent control of two nuclear spins using the anisotropic hyperfine interaction,"We demonstrate coherent control of two nuclear spins mediated by the magnetic
resonance of a hyperfine-coupled electron spin. This control is used to create
a double nuclear coherence in one of the two electron spin manifolds, starting
from an initial thermal state, in direct analogy to the creation of an
entangled (Bell) state from an initially pure unentangled state. We identify
challenges and potential solutions to obtaining experimental gate fidelities
useful for quantum information processing in this type of system.",1107.2884v2
2011-08-09,Evidence for spin memory in the electron phase coherence in graphene,"We measure the dependence of the conductivity of graphene as a function of
magnetic field, temperature and carrier density and discover a saturation of
the dephasing length at low temperatures that we ascribe to spin memory
effects. Values of the spin coherence length up to eight microns are found to
scale with the mean free path. We consider different origins of this effect and
suggest that it is controlled by resonant states that act as magnetic-like
defects. By varying the level of disorder, we demonstrate that the spin
coherence length can be tuned over an order of magnitude.",1108.2067v1
2011-09-19,Storage and Retrieval of a Microwave Field in a Spin Ensemble,"We report the storage and retrieval of a small microwave field from a
superconducting resonator into collective excitations of a spin ensemble. The
spins are nitrogen-vacancy centers in a diamond crystal. The storage time of
the order of 30 ns is limited by inhomogeneous broadening of the spin ensemble.",1109.3960v1
2011-09-22,Probing the spin states of three interacting electrons in quantum dots,"We observe a low-lying sharp spin mode of three interacting electrons in an
array of nanofabricated AlGaAs/GaAs quantum dots by means of resonant inelastic
light scattering. The finding is enabled by a suppression of the inhomogeneous
contribution to the excitation spectra obtained by reducing the number of
optically-probed quantum dots. Supported by configuration-interaction
calculations we argue that the observed spin mode offers a direct probe of
Stoner ferromagnetism in the simplest case of three interacting spin one-half
fermions.",1109.4758v1
2011-10-24,Spin-orbital Kondo effect in a parallel double quantum dot,"Transport properties of the two-orbital Kondo effect involving both spin and
orbital (pseudospin) degrees of freedom were examined in a parallel double
quantum dot with a sufficient interdot Coulomb interaction and negligibly small
interdot tunneling. The Kondo effect was observed at the interdot Coulomb
blockade region with degeneracies of both spin and orbital degrees of freedom.
When the orbital degeneracy is lifted by applying a finite detuning, the Kondo
resonance exhibits a triple-peak structure, indicating that both spin and
orbital contributions are involved.",1110.5130v1
2012-06-15,Optical control of the spin state of two Mn atoms in a quantum dot,"We report on the optical spectroscopy of the spin of two magnetic atoms (Mn)
embedded in an individual quantum dot interacting with either a single
electron, a single exciton and single trion. As a result of their interaction
to a common entity, the Mn spins become correlated. The dynamics of this
process is probed by time resolved spectroscopy, that permits to determine the
optical orientation time in the range of a few tens of $ns$. In addition, we
show that the energy of the collective spin states of the two Mn atoms can be
tuned through the optical Stark effect induced by a resonant laser field.",1206.3491v1
2012-10-18,Enhanced Inverse Spin-Hall Effect in Ultrathin Ferromagnetic/Normal Metal Bilayers,"We measure electrically detected ferromagnetic resonance in microdevices
patterned from ultra-thin Co/Pt bilayers. Spin pumping and rectification
voltages are observed and distinguished via their angular dependence. The
spin-pumping voltage shows an unexpected increase as the cobalt thickness is
reduced below 2 nm. This enhancement allows more efficient conversion of spin
to charge current and motivates a theory modelling the dependence of impurity
scattering on surface roughness.",1210.5230v1
2012-11-12,Spin polarization and magnetoresistance through a ferromagnetic barrier in bilayer graphene,"We study spin dependent transport through a magnetic bilayer graphene
nanojunction configured as two dimensional normal/ferromagnetic/normal
structure where the gate-voltage is applied on the layers of ferromagnetic
graphene. Based on the fourband Hamiltonian, conductance is calculated by using
Landauer Butikker formula at zero temperature. For parallel configuration of
the ferromagnetic layers of bilayer graphene, the energy band structure is
metallic and spin polarization reaches to its maximum value close to the
resonant states, while for antiparallel configuration, the nanojunction behaves
as a semiconductor and there is no spin filtering. As a result, a huge
magnetoresistance is achievable by altering the configurations of ferromagnetic
graphene especially around the band gap.",1211.2701v1
2012-11-29,Pumping $ac$ Josephson current in the Single Molecular Magnets by spin nutation,"We demonstrate that an {\it ac} Josephson current is pumped through the
Single Molecular Magnets (SMM) by the spin nutation. The spin nutation is
generated by applying a time dependent magnetic field to the SMM. We obtain the
flowing charge current through the junction by working in the tunneling limit
and employing Green's function technique. At the resonance conditions some
discontinuities and divergencies are appeared in the normal and Josephson
currents, respectively. Such discontinuities and divergencies reveal themselves
when the absorbed/emitted energy, owing to the interaction of the
quasiparticles with the spin dynamics are in the range of the superconducting
gap.",1211.6879v1
2012-12-18,Spin system trajectory analysis under optimal control pulses,"Several methods are proposed for the analysis, visualization and
interpretation of high-dimensional spin system trajectories produced by quantum
mechanical simulations. It is noted that expectation values of specific
observables in large spin systems often feature fast, complicated and
hard-to-interpret time dynamics and suggested that populations of carefully
selected subspaces of states are much easier to analyze and interpret. As an
illustration of the utility of the proposed methods, it is demonstrated that
the apparent ""noisy"" appearance of many optimal control pulses in NMR and EPR
spectroscopy is an illusion - the underlying spin dynamics is shown to be
smooth, orderly and very tightly controlled.",1212.4454v1
2013-06-18,Ultrasensitive Detection of Majorana Fermions via Spin-based Optomechanics with Carbon Nanotubes,"We propose a novel optical method to detect the existence of Majorana
fermions at the ends of the semiconductor nanowire via the coupling to an
electron spin trapped on a carbon nanotube resonator under the control of a
strong pump field and a weak probe field. The coupling strength of Majorana
fermion to the spin in the carbon nanotube and the decay rate of the Majorana
fermion can be easily measured from the probe absorption spectrum via
manipulating the spin-mechanical coupling in the suspended\ carbon nanotube.
The scheme proposed here will open a good perspective for its applications in
all-optical controlled Majorana fermion-based quantum computation and quantum
information processing.",1306.4102v1
2014-02-13,Inhomogeneous slowing down of spin fluctuations induced by charge stripe order in 1/8-doped lanthanum cuprates,"We report $^{139}$La nuclear magnetic resonance (NMR) measurements on
La$_{2-x}$Sr$_x$CuO$_4$ ($0.07\leq x \leq 0.15$) and La$_{2-x}$Ba$_x$CuO$_4$
($x=1/8$) single crystals, focusing on the spin freezing observed in 1/8-doped
lanthanum cuprates. Charge stripe order seems to induce the inhomogeneous
slowing down of spin fluctuations toward spin order and compete with
superconductivity.",1402.3077v3
2014-03-18,31P NMR Investigation of the Superconductor LiFeP (Tc = 5 K),"We investigate the static and dynamic spin susceptibility of the 111 type
Fe-based superconductor LiFeP with Tc ~ 5 K through the measurement of Knight
shift 31K and the spin-lattice relaxation rate 1/T1 at 31P site by nuclear
magnetic resonance. The constant 31K, small magnitudes of 1/T1T, along with the
resistivity rho ~ T^2 all point to the weak spin correlations in LiFeP. 1/T1T
display small enhancement toward Tc, indicating that the superconductivity is
intimately correlated with the antiferromagnetic spin fluctuations.",1403.4458v1
2014-09-16,Sensitivity to small perturbations in systems of large quantum spins,"We investigate the sensitivity of nonintegrable large-spin quantum lattices
to small perturbations with a particular focus on the time reversal experiments
known in statistical physics as ""Loschmidt echoes"" and in nuclear magnetic
resonance (NMR) as ""magic echoes"". Our numerical simulations of quantum
spin-$7\frac{1}{2}$ clusters indicate that there is a regime, where Loschmidt
echoes exhibit nearly exponential sensitivity to small perturbations with
characteristic constant approximately equal to twice the value of the largest
Lyapunov exponent of the corresponding classical spin clusters. The above
theoretical results are verifiable by NMR experiments on solids containing
large-spin nuclei.",1409.4763v1
2014-09-22,All optical control of a single electron spin in diamond,"Precise coherent control of the individual electronic spins associated with
atom-like impurities in the solid state is essential for applications in
quantum information processing and quantum metrology. We demonstrate
all-optical initialization, fast coherent manipulation, and readout of the
electronic spin of the negatively charged nitrogen-vacancy (NV$^-$) center in
diamond at T$\sim$7K. We then present the observation of a novel double-dark
resonance in the spectroscopy of an individual NV center. These techniques open
the door for new applications ranging from robust manipulation of spin states
using geometric quantum gates to quantum sensing and information processing.",1409.6372v1
2015-02-24,Spin rectification for collinear and non-collinear magnetization and external magnetic field configurations,"Spin rectification in a single crystal Fe/Au/Fe sandwich is electrically
detected for collinear and non-collinear magnetization and external magnetic
field configurations. The line shape, line width and signal polarity are
analysed. The spin rectication theory has been much extended by taking the
magneto-crystalline anisotropy and shape anisotropy into account, which
explained non-collinear resonances and agrees very well with experimental data.
Thus, a comprehensive understanding of spin rectification in ferromagnetic
metal was demonstrated in this work.",1502.06859v1
2015-04-08,Electron spin polarization by isospin ordering in correlated two-layer quantum Hall systems,"Enhancement of the electron spin polarization in a correlated two-layer
two-dimensional electron system at a total Landau level filling factor of one
is reported. Using resistively detected nuclear magnetic resonance, we
demonstrate that the electron spin polarization of two closely-spaced
two-dimensional electron systems becomes maximized when inter-layer Coulomb
correlations establish spontaneous isospin ferromagnetic order. This
correlation-driven polarization dominates over the spin polarizations of
competing single-layer fractional Quantum Hall states under electron density
imbalances.",1504.02007v1
2015-09-14,Spin measurement using cycling transitions of a two-electron quantum dot molecule,"Two-electron charged self-assembled quantum dot molecules exhibit a
decoherence-avoiding singlet-triplet qubit subspace and an efficient
spin-photon interface. Here, we demonstrate that the cycling transitions
originating from auxiliary ground states in the same system allow for an
efficient optical read-out of a singlet-triplet qubit. By implementing a
spin-selective state transfer to the auxiliary state using a resonant laser
field, we observe an improvement approaching two orders of magnitude in
fidelity as compared to spin measurement by light scattering directly from the
qubit states. Embedding the quantum dot molecule inside a low quality-factor
micro-cavity structure should enable single-shot qubit read-out.",1509.04171v1
2018-06-21,Pulse sequences for controlled 2- and 3-qubit gates in a hybrid quantum register,"We propose and demonstrate a quantum control scheme for hybrid quantum
registers that can reduce the operation time, and therefore the effects of
relaxation, compared to existing implementations. It combines resonant
excitation pulses with periods of free precession under the internal
Hamiltonian of the qubit system. We use this scheme to implement quantum gates
like controlled-NOT operations on electronic and nuclear spins of the
nitrogen-vacancy center in diamond. As a specific application, we transfer
population between electronic and nuclear spin qubits and use it to measure the
Rabi oscillations of a nuclear spin in a system with multiple coupled spins.",1806.08408v1
2018-09-07,Optimal Spin Squeezed Steady State induced by the dynamics of non-hermtian hamiltonians,"In this work, we study the time evolution of a coherent spin state under the
action of a non-hermitian hamiltonian. The hamiltonian is modeled by a one-axis
twisting term plus a Lipkin-type interaction. We show that when the Lipkin
interaction is switched on, depending on the relative values of the coupling
constants, the initial state evolves into a steady squeezed state which
minimizes the Uncertainty Relations, Intelligent Spin State. We apply this
result to look for the generation of an steady intelligent spin state from an
ensemble of nitrogen vacancy colour centers in diamond coupled to a mechanical
resonator.",1809.02683v1
2012-09-12,Coherent spin control by electrical manipulation of the magnetic anisotropy,"High-spin paramagnetic manganese defects in polar piezoelectric zinc oxide
exhibit a simple almost axial anisotropy and phase coherence times of the order
of a millisecond at low temperatures. The anisotropy energy is tunable using an
externally applied electric field. This can be used to control electrically the
phase of spin superpositions and to drive spin transitions with resonant
microwave electric fields.",1209.2745v2
2012-09-19,Dynamical evolution of an inverted spin ensemble in a cavity: Inhomogeneous broadening as a stabilizing mechanism,"We study the evolution of an inverted spin ensemble coupled to a cavity. The
inversion itself presents an inherent instability of the system; however, the
inhomogeneous broadening of spin-resonance frequencies presents a stabilizing
mechanism, and a stability criterion is derived. The detailed behavior of mean
values and variances of the spin components and of the cavity field is
accounted for under both stable and unstable conditions.",1209.4167v1
2018-12-30,Entangling and squeezing atoms by weak measurement,"A weak measurement approach is proposed to entangle and squeeze atoms. We
show that even for very small coupling strength between light and atoms, one
can achieve large squeezing unattainable with normal measurement-based
squeezing. Post-selecting the photons interacting with spins via a weak
off-resonant quantum nondemolition interaction (QND) in a state nearly
orthogonal to its initial state can strengthen the entanglement among
elementary spins and thus enhance spin squeezing. The squeezing process is
probabilistic but the created state is unconditionally determined. Further
control of the post-selection parameter and the detection process can transform
the QND-like spin squeezing into the one-axis-twisting or even
two-axis-twisting type.",1812.11548v1
2017-02-24,Elucidation of the helical spin structure of FeAs,"We present the results of resonant x-ray scattering measurements and
electronic structure calculations on the monoarsenide FeAs. We elucidate
details of the magnetic structure, showing the ratio of ellipticity of the spin
helix is larger than previously thought, at 2.58(3), and reveal both a
right-handed chirality and an out of plane component of the magnetic moments in
the spin helix. We find that electronic structure calculations and analysis of
the spin-orbit interaction are able to qualitatively account for this canting.",1702.07660v1
2018-04-04,Independence of spin-orbit torques from the exchange bias direction in Ni$_{81}$Fe$_{19}$/IrMn bilayers,"We investigated a possible correlation between spin Hall angles and exchange
bias in Ni$_{81}$Fe$_{19}$/IrMn samples by performing spin torque ferromagnetic
resonance measurements. This correlation is probed by patterning of
Ni$_{81}$Fe$_{19}$/IrMn bilayers in different relative orientations with
respect to the exchange bias direction. The measured voltage spectra allow a
quantitative determination of spin Hall angles, which are independent of the
orientation around 2.8\pm0.3%.",1804.01612v1
2019-03-29,Adiabatic population transfer of dressed spin states with quantum optimal control,"We report theoretical studies of adiabatic population transfer using dressed
spin states. Quantum optimal control using the algorithm of Chopped Random
Basis (CRAB) has been implemented in a negatively charged diamond nitrogen
vacancy center that is coupled to a strong and resonant microwave field. We
show that the dressed spin states are highly effective in suppressing effects
of spin dephasing on adiabatic population transfer. The numerical simulation
also demonstrates that CRAB-based quantum optimal control can enable an
efficient and robust adiabatic population transfer.",1903.12651v1
2021-08-02,Trapping the carrier in the spin-locked MoS2 atomic valley by absorption of chiral L-cysteine,"This work, demonstrate enhanced valley contrasting spin-momentum locked
chiral states at van der Waal interface of chiral L-cysteine and
mono-atomically thin MoS2 placed at Si/SiO2 substrate at ambient condition.
Helicity dependent photoluminescence and resonance Raman measurement highlights
spin-locked transitions for chiral L-cysteine modified SL MoS2 at ambient
condition. Selective adsorption of chiral L-cysteine dimer /cystine on
monolayer MoS2, stabilizes the in-plane effective magnetic field due to Si/SiO2
substrate and blocks the intervalley spin relaxation. The observed polarisation
efficiency will be useful for improving the functionality of valley-based light
emitting diode (LEDs) and encoding information in logical devices.",2108.01106v2
2008-06-24,Spin-vortex nucleation in a Bose-Einstein condensate by a spin-dependent rotating trap,"A method to produce a spin-dependent rotating potential using near-resonant
circularly polarized laser beams is proposed. It is shown that half-quantum
vortices are nucleated in a spinor Bose-Einstein condensate with an
antiferromagnetic interaction. In contrast to the vortex nucleation in a scalar
BEC, the spin-vortex nucleation occurs at a low rotation frequency ($\simeq 0.1
\omega_\perp$ with $\omega_\perp$ being the radial trap frequency) in a short
nucleation time $\simeq 50$ ms without dissipation. A method for nondestructive
measurement of half-quantum vortices is discussed.",0806.3840v1
2019-01-29,Electron interferometry and quantum spin Hall phase in silicene,"We discuss devices for detection of the topological insulator phase based on
the two-path electron interference. For that purpose we consider buckled
silicene for which a local energy gap can be opened by vertical electric field
to close one of the paths and for which the quantum spin Hall insulator
conditions are controlled by the Fermi energy. In quantum spin Hall phase the
interference is absent due to the separation of the spin currents and the
conductance of the devices include sharp features related to localized
resonances. In the normal transport conditions the two-path interference
produces a regular Aharonov-Bohm oscillations in the external magnetic field.",1901.10161v1
2021-01-20,Twisted light-induced spin-spin interaction in a chiral helimagnet,"We theoretically investigate how the orbital angular momentum of light can
affect a chiral magnetic order. Here, we consider a metallic chiral helimagnet,
which is under stationary radiation of a resonant optical vortex beam. We
propose a novel interaction between local spins considering microscopic
interactions between an optical vortex and electrons. This vortex-induced
interaction modulates the chiral magnetic order in an entirely different way
than an external magnetic field does. Our spin modulation technique may pave a
route to create a unique topological or chiral structure for future
opto-spintronics devices.",2101.10131v2
2021-11-09,Parametric mechanism of magnetization reversal in FeCoB nanomagnet by a magnetic field of spin-accumulated electrons,"Spin-polarized electrons are accumulated at nanomagnet boundaries due to the
Spin Hall effect. The small magnetic field, which is induced by the spin
accumulation, is able to reverse the nanomagnet magnetization when the
conditions of parametric resonance are met. The features of this parametric
mechanism of magnetization reversal are studied experimentally and
theoretically. It is shown that the efficient parametric magnetization reversal
is possible for both cases when the electron current is modulated at the Larmor
frequency and when the current is not modulated at all.",2111.05438v1
2021-12-22,Observation of quantum phase-synchronization in a nuclear spin-system,"We report an experimental study of phase-synchronization in a pair of
interacting nuclear spins subjected to an external drive in nuclear magnetic
resonance architecture. A weak transition-selective radio-frequency field
applied on one of the spins is observed to cause phase-localization, which is
experimentally established by measuring the Husimi distribution function under
various drive conditions. To this end, we have developed a general
interferometric technique to directly extract values of the Husimi function via
the transverse magnetization of the undriven nuclear spin. We further verify
the robustness of synchronization to detuning in the system by studying the
Arnold tongue behaviour.",2112.12088v2
2022-01-28,Theory of spin-excitation anisotropy in the nematic phase of FeSe obtained from RIXS measurements,"Recent resonant inelastic x-ray scattering (RIXS) experiments have detected a
significant high-energy spin-excitation anisotropy in the nematic phase of the
enigmatic iron-based superconductor FeSe, whose origin remains controversial.
We apply an itinerant model previously used to describe the spin-excitation
anisotropy as measured by neutron scattering measurements, with magnetic
fluctuations included within the RPA approximation. The calculated RIXS cross
section exhibits overall agreement with the RIXS data, including the high
energy spin-excitation anisotropy.",2201.12008v2
2022-07-15,Target normal single-spin asymmetry in inclusive electron-nucleon scattering with two-photon exchange: Analysis using $1/N_c$ expansion,"We calculate the target normal single-spin asymmetry caused by two-photon
exchange in inclusive electron-nucleon scattering in the resonance region. Our
analysis uses the $1/N_c$ expansion of low-energy QCD and combines $N$ and
$\Delta$ intermediate and final states using the contracted $SU(4)$ spin-flavor
symmetry. The normal spin asymmetry obtained in leading-order accuracy in
$1/N_c$ has magnitude $\sim 10^{-2}$ and different sign in $ep$ and $en$
scattering. It can be measured in electron scattering at lab energies $\sim$
0.5-1.5 GeV and provides a clean probe of two-photon exchange dynamics.",2207.07588v1
2023-11-24,Plasmonically engineered nitrogen-vacancy spin readout,"Ultra-precise readout of single nitrogen-vacancy (NV) spins hold promise for
major advancements in quantum sensing and computing technologies. We predict
significant brightness and contrast enhancements in NV spin qubit readout and
optically detected magnetic resonance (ODMR) arising from plasmonic
interaction. We present a rigorous theory verified using existing measurements
in the literature for such predictions. Plasmonic spin readout enhancements
selectively manifest in carefully engineered parameter regions, necessitating
rigorous modelling prior to experimentation.",2311.14266v1
1999-05-20,Spin dynamics simulation of the three-dimensional XY model: Structure factor and transport properties,"We present extensive Monte-Carlo spin dynamics simulations of the classical
XY model in three dimensions on a simple cubic lattice with periodic boundary
conditions. A recently developed efficient integration algorithm for the
equations of motion is used, which allows a substantial improvement of
statistics and large integration times. We find spin wave peaks in a wide range
around the critical point and spin diffusion for all temperatures. At the
critical point we find evidence for a violation of dynamic scaling in the sense
that independent components of the dynamic structure factor S(q,w) require
different dynamic exponents in order to obtain scaling. Below the critical
point we investigate the dispersion relation of the spin waves and the
linewidths of S(q,w) and find agreement with mode coupling theory. Apart from
strong spin wave peaks we observe additional peaks in S(q,w) which can be
attributed to two-spin wave interactions. The overall lineshapes are also
discussed and compared to mode coupling predictions. Finally, we present first
results for the transport coefficient D(q,w) of the out-of-plane magnetization
component at the critical point, which is related to the thermal conductivity
of He4 near the superfluid-normal transition.",9905295v1
2000-12-01,Magnetic and orbital ordering in cuprates and manganites,"The mechanisms of magnetic and orbital interactions due to double exchange
(DE) and superexchange (SE) in transition metal oxides with degenerate e_g
orbitals are presented. Specifically, we study the effective spin-orbital
models derived for the d^9 ions as in KCuF_3, and for the d^4 ions as in
LaMnO_3, for spins S=1/2 and S=2, respectively. Such models are characterized
by three types of elementary excitations: spin waves, orbital waves, and
spin-and-orbital waves. The SE interactions between Cu^{2+} (d^9) ions are
inherently frustrated, which leads to a new mechanism of spin liquid which
operates in three dimensions. The SE between Mn^{3+} (d^4) ions explains the
A-type antiferromagnetic order in LaMnO_3 which coexists with the orbital
order. In contrast, the ferromagnetic metallic phase and isotropic spin waves
observed in doped manganites are explained by DE for degenerate e_g orbitals.
It is shown that although a hole does not couple to spin excitations in
ferromagnetic planes of LaMnO_3, the orbital excitations change the energy
scale for the coherent hole propagation and cause a large redistribution of
spectral weight. Finally, we point out some open problems in the present
understanding of doped manganites.",0012013v1
2005-08-08,Site dilution of quantum spins in the honeycomb lattice,"We discuss the effect of site dilution on both the magnetization and the
density of states of quantum spins in the honeycomb lattice, described by the
antiferromagnetic Heisenberg spin-S model. For this purpose a real-space
Bogoliubov-Valatin transformation is used. In this work we show that for the
S>1/2 the system can be analyzed in terms of linear spin wave theory. For spin
S=1/2, however, the linear spin wave approximation breaks down. In this case,
we have studied the effect of dilution on the staggered magnetization using the
Stochastic Series Expansion Monte Carlo method. Two main results are to be
stressed from the Monte Carlo method: (i) a better value for the staggered
magnetization of the undiluted system, m=0.2677(6); (ii) a finite value of the
staggered magnetization of the percolating cluster at the classical percolation
threshold, showing that there is no quantum critical transition driven by
dilution in the Heisenberg model. In the solution of the problem using linear
the spin wave method we pay special attention to the presence of zero energy
modes. Using a combination of linear spin wave analysis and the recursion
method we were able to obtain the thermodynamic limit behavior of the density
of states for both the square and the honeycomb lattices. We have used both the
staggered magnetization and the density of states to analyze neutron scattering
experiments and Neel temperature measurements on quasi-two- -dimensional
honeycomb systems. Our results are in quantitative agreement with experimental
results on Mn_pZn_{1-p}PS_3 and on the Ba(Ni_pMg_{1-p})_2V_2O_8.",0508204v1
2007-02-01,Intensity of Brillouin light scattering from spin waves in magnetic multilayers with noncollinear spin configurations: Theory and experiment,"The scattering of photons from spin waves (Brillouin light scattering -- BLS)
is a well-established technique for the study of layered magnetic systems. The
information about the magnetic state and properties of the sample is contained
in the frequency position, width, and intensity of the BLS peaks. Previously
[Phys. Rev. B 67, 184404 (2003)], we have shown that spin wave frequencies can
be conveniently calculated within the ultrathin film approach, treating the
intralayer exchange as an effective bilinear interlayer coupling between thin
virtual sheets of the ferromagnetic layers. Here we give the consequent
extension of this approach to the calculation of the Brillouin light scattering
(BLS) peak intensities. Given the very close relation of the BLS cross-section
to the magneto-optic Kerr effect (MOKE), the depth-resolved longitudinal and
polar MOKE coefficients calculated numerically via the usual magneto-optic
formalism can be employed in combination with the spin wave precessional
amplitudes to calculate full BLS spectra for a given magnetic system. This
approach allows an easy calculation of BLS intensities even for noncollinear
spin configurations including the exchange modes. The formalism is applied to a
Fe/Cr/Fe/Ag/Fe trilayer system with one antiferromagnetically coupling spacer
(Cr). Good agreement with the experimental spectra is found for a wide variety
of spin configurations.",0702021v1
2013-11-11,Three-dimensional light-matter interface for collective spin squeezing in atomic ensembles,"We study the three-dimensional nature of the quantum interface between an
ensemble of cold, trapped atomic spins and a paraxial laser beam, coupled
through a dispersive interaction. To achieve strong entanglement between the
collective atomic spin and the photons, one must match the spatial mode of the
collective radiation of the ensemble with the mode of the laser beam while
minimizing the effects of decoherence due to optical pumping. For ensembles
coupling to a probe field that varies over the extent of the cloud, the set of
atoms that indistinguishably radiates into a desired mode of the field defines
an inhomogeneous spin wave. Strong coupling of a spin wave to the probe mode is
not characterized by a single parameter, the optical density, but by a
collection of different effective atom numbers that characterize the coherence
and decoherence of the system. To model the dynamics of the system, we develop
a full stochastic master equation, including coherent collective scattering
into paraxial modes, decoherence by local inhomogeneous diffuse scattering, and
backaction due to continuous measurement of the light entangled with the spin
waves. This formalism is used to study the squeezing of a spin wave via
continuous quantum nondemolition (QND) measurement. We find that the greatest
squeezing occurs in parameter regimes where spatial inhomogeneities are
significant, far from the limit in which the interface is well approximated by
a one-dimensional, homogeneous model.",1311.2328v2
2018-03-23,Direct observation of incommensurate magnetism in Hubbard chains,"The interplay between magnetism and doping is at the origin of exotic
strongly correlated electronic phases and can lead to novel forms of magnetic
ordering. One example is the emergence of incommensurate spin-density waves
with a wave vector that does not match the reciprocal lattice. In one dimension
this effect is a hallmark of Luttinger liquid theory, which also describes the
low energy physics of the Hubbard model. Here we use a quantum simulator based
on ultracold fermions in an optical lattice to directly observe such
incommensurate spin correlations in doped and spin-imbalanced Hubbard chains
using fully spin and density resolved quantum gas microscopy. Doping is found
to induce a linear change of the spin-density wave vector in excellent
agreement with Luttinger theory predictions. For non-zero polarization we
observe a decrease of the wave vector with magnetization as expected from the
Heisenberg model in a magnetic field. We trace the microscopic origin of these
incommensurate correlations to holes, doublons and excess spins which act as
delocalized domain walls for the antiferromagnetic order. Finally, when
inducing interchain coupling we observe fundamentally different spin
correlations around doublons indicating the formation of a magnetic polaron.",1803.08892v1
2020-11-09,Classical many-body chaos with and without quasiparticles,"We study correlations, transport and chaos in a Heisenberg magnet as a
classical model many-body system. By varying temperature and dimensionality, we
can tune between settings with and without symmetry breaking and accompanying
collective modes or quasiparticles. We analyse both conventional and
out-of-time-ordered spin correlators (`decorrelators') to track the spreading
of a spatiotemporally localised perturbation -- the wingbeat of the butterfly
-- as well as transport coefficients and Lyapunov exponents. We identify a
number of qualitatively different regimes. Trivially, at $T=0$, there is no
dynamics at all. In the limit of low temperature, $T=0^+$, integrability
emerges, with infinitely long-lived magnons; here the wavepacket created by the
perturbation propagates ballistically, yielding a lightcone at the spin wave
velocity which thus subsumes the butterfly velocity; inside the lightcone, a
pattern characteristic of the free spin wave spectrum is visible at short
times. On top of this, residual interactionslead to spin wave lifetimes which,
while divergent in this limit, remain finite at any nonzero $T$. At the longest
times, this leads to a `standard' chaotic regime; for this regime, we show that
the Lyapunov exponent is simply proportional to the inverse spin-wave lifetime.
Visibly strikingly, between this and the `short-time' integrable regimes, a
scarred regime emerges: here, the decorrelator is spatiotemporally highly
non-uniform, being dominated by rare and random scattering events seeding
secondary lightcones. As the spin correlation length decreases with increasing
$T$, the distinction between these regimes disappears and at high temperature
the previously studied chaotic paramagnetic regime emerges. For this, we
elucidate how, somewhat counterintuitively, the ballistic butterfly velocity
arises from a diffusive spin dynamics.",2011.04700v1
2019-07-05,Propagation length of antiferromagnetic magnons governed by domain configurations,"The compensated magnetic order and characteristic, terahertz frequencies of
antiferromagnetic materials makes them promising candidates to develop a new
class of robust, ultra-fast spintronic devices. The manipulation of
antiferromagnetic spin-waves in thin films is anticipated to lead to new exotic
phenomena such as spin-superfluidity, requiring an efficient propagation of
spin-waves in thin films. However, the reported decay length in thin films has
so far been limited to a few nanometers. In this work, we achieve efficient
spin-wave propagation, over micrometer distances, in thin films of the
insulating antiferromagnet hematite with large magnetic domains whilst
evidencing much shorter attenuation lengths in multidomain thin films. Through
transport and magnetic imaging, we conclude on the role of the magnetic domain
structure and spin-wave scattering at domain walls to govern the transport. We
manipulate the spin transport by tailoring the domain configuration through
field cycle training. For the appropriate crystalline orientation, zero-field
spin-transport is achieved across micrometers, as required for device
integration.",1907.02751v2
2021-01-29,Dynamically stable negative-energy states induced by spin-transfer torques,"We investigate instabilities of the magnetic ground state in ferromagnetic
metals that are induced by uniform electrical currents, and, in particular, go
beyond previous analyses by including dipolar interactions. These instabilities
arise from spin-transfer torques that lead to Doppler shifted spin waves. For
sufficiently large electrical currents, spin-wave excitations have negative
energy with respect to the uniform magnetic ground state, while remaining
dynamically stable due to dissipative spin-transfer torques. Hence, the uniform
magnetic ground state is energetically unstable, but is not able to dynamically
reach the new ground state. We estimate this to happen for current densities $
j\gtrsim (1-D/D_c)10^{13} \mathrm{A/m^2} $ in typical thin film experiments,
with $ D $ the Dzyaloshinskii-Moriya interaction constant, and $ D_c $ the
Dzyaloshinskii-Moriya interaction that is required for spontaneous formation of
spirals or skyrmions. These current densities can be made arbitrarily small for
ultrathin film thicknesses at the order of nanometers, due to surface- and
interlayer effects. From an analogue gravity perspective, the stable negative
energy states are an essential ingredient to implement event horizons for
magnons -- the quanta of spin waves -- giving rise to e.g. Hawking radiation
and can be used to significantly amplify spin waves in a so-called black-hole
laser.",2101.12544v1
2021-12-17,Combined unitary and symmetric group approach applied to low-dimensional spin systems,"A novel combined unitary and symmetric group approach is used to study the
spin-$\frac{1}{2}$ Heisenberg model and related Fermionic systems in a
spin-adapted representation, using a linearly-parameterised Ansatz for the
many-body wave function. We show that a more compact ground state wave function
representation is obtained when combining the symmetric group, $\mathcal{S}_n$,
in the form of permutations of the underlying lattice site ordering, with the
cumulative spin-coupling based on the unitary group, $\mathrm{U}(n)$. In
one-dimensional systems the observed compression of the wave function is
reminiscent of block-spin renormalization group approaches, and allows us to
study larger lattices (here taken up to 80 sites) with the spin-adapted full
configuration interaction quantum Monte Carlo method, which benefits from the
sparsity of the Hamiltonian matrix and the corresponding sampled eigenstates
that emerge from the reordering. We find that in an optimal lattice ordering
the configuration state function with highest weight already captures with high
accuracy the spin-spin correlation function of the exact ground state wave
function. This feature is found for more general lattice models, such as the
Hubbard model, and ab initio quantum chemical models, in this work exemplified
by a one-dimensional hydrogen chain. We also provide numerical evidence that
the optimal lattice ordering for the unitary group approach is not generally
equivalent to the optimal ordering obtained for methods based on matrix-product
states, such as the density-matrix renormalization group approach.",2112.09594v1
2022-04-05,Single domain stripe order in a high-temperature superconductor,"The coupling of spin, charge and lattice degrees of freedom results in the
emergence of novel states of matter across many classes of strongly correlated
electron materials. A model example is unconventional superconductivity, which
is widely believed to arise from the coupling of electrons via spin
excitations. In cuprate high-temperature superconductors, the interplay of
charge and spin degrees of freedom is also reflected in a zoo of charge and
spin-density wave orders that are intertwined with superconductivity. A key
question is whether the different types of density waves merely coexist or are
indeed directly coupled. Here we use a novel neutron diffraction technique with
superior beam-focusing that allows us to probe the subtle spin-density wave
order in the prototypical high-temperature superconductor La1.88Sr0.12CuO4
under applied uniaxial pressure to demonstrate that it is immediately coupled
with charge-density wave order. Our result shows that suitable models for
high-temperature superconductivity must equally account for charge and spin
degrees of freedom via uniaxial charge-spin stripe fluctuations.",2204.02304v1
2022-10-04,The BKT Transition and its Dynamics in a Spin Fluid,"We study the effect of particle mobility on phase transitions in a spin fluid
in two dimensions. The presence of a phase transition of the BKT universality
class is shown in an off-lattice model of particles with purely repulsive
interaction employing computer simulations. A critical spin wave region $0 < T
< T_{\textrm{BKT}}$ is found with a non-universal exponent $\eta(T)$ that
follows the shape suggested by BKT theory, including a critical value
consistent with $\eta_{\textrm{BKT}} = 1/4$. One can observe a transition from
power-law decay to exponential decay in the static correlation functions at the
transition temperature $T_{\textrm{BKT}}$, which is supported by finite-size
scaling analysis. A critical temperature $T_{\textrm{BKT}} = 0.17(1)$ is
suggested. Investigations into the dynamic aspects of the phase transition are
carried out. The short-time behavior of the incoherent spin autocorrelation
function agrees with the Nelson-Fisher prediction, whereas the long-time
behavior differs from the finite-size scaling known for the static XY model.
Analysis of coherent spin wave dynamics shows that the spin wave peak is a
propagating mode that can be reasonably well fitted by hydrodynamic theory. The
mobility of the particles strongly enhances damping of the spin waves, but the
model lies still within the dynamic universality class of the standard XY
model.",2210.01838v1
2001-11-08,Resonances and Quantum Scattering for the Morse Potential as a Barrier,"Quantum scattering in the presence of a potential valley followed by a
barrier is examined for the case of a Morse potential, for which exact analytic
solutions to the Schr\UNICODE{0xf6}dinger equation are known in terms of
confluent hypergeometric functions. For our application the potential is
characterized by three parameters: the height of the barrier, the distance of
the barrier from the origin of the radial variable $r,$ and a diffuseness
parameter. The wave function, defined in the interval $0\leq r<\infty ,$ is
required to vanish at $r=0,$ and hence represents a radial partial wave for
zero angular momentum. The vanishing at $r=0$ requires a special combination of
hypergeometric functions, and can lead to resonances for incident energies
which occur below the top of the barrier. Numerical values for the analytical
phase shifts are presented in and outside the resonant regions, and the
corresponding properties of the scattering S-matrix are examined in the complex
momentum plane, mainly for pedagogical reasons. The validity of the
Breit-Wigner approximation to the resonant phase shifts is tested, and the
motion of a ''resonant'' wave packet slowly leaking out of the valley region is
also displayed.",0111027v2
2007-05-24,Slow wave resonance in periodic stacks of anisotropic layers,"We consider transmission band edge resonance in periodic layered structures
involving birefringent layers. Previously we have shown that the presence of
birefringent layers with misaligned in-plane anisotropy can dramatically
enhance the performance of the photonic-crystal Fabry-Perot resonator. It
allows to reduce its size by an order of magnitude without compromising on its
performance. The key characteristic of the enhanced photonic-crystal cavity is
that its Bloch dispersion relation displays a degenerate photonic band edge,
rather than only regular ones. This can be realized in specially arranged
stacks of misaligned anisotropic layers. On the down side, the presence of
birefringent layers results in the Fabry-Perot resonance being coupled only
with one (elliptic) polarization component of the incident wave, while the
other polarization component is reflected back to space. In this paper we show
how a small modification of the periodic layered array can solve the above
fundamental problem and provide a perfect impedance match regardless of the
incident wave polarization, while preserving the giant transmission resonance,
characteristic of a degenerate photonic band edge. Both features are of
critical importance for a variety of practical applications, including
antennas, light amplification, optical and microwave filters, etc.",0705.3495v3
2010-02-25,A theory of MHD instability of an inhomogeneous plasma jet,"A problem of the instability of an inhomogeneous axisymmetric plasma jet in a
parallel magnetic field is solved. The jet boundary becomes, under certain
conditions, unstable relative to magnetosonic oscillations (Kelvin-Helmholtz
instability) in the presence of a shear flow at the jet boundary. Because of
its internal inhomogeneity the plasma jet has resonance surfaces, where
conversion takes place between various modes of plasma MHD oscillations.
Propagating in inhomogeneous plasma, fast magnetosonic waves drive the Alfven
and slow magnetosonic oscillations, tightly localized across the magnetic
shells, on the resonance surfaces. MHD oscillation energy is absorbed in the
neighbourhood of these resonance surfaces. The resonance surfaces disappear for
the eigen-modes of slow magnetosonic waves propagating in the jet waveguide.
The stability of the plasma MHD flow is determined by competition between the
mechanisms of shear flow instability on the boundary and wave energy
dissipation because of resonant MHD-mode coupling. The problem is solved
analytically, in the WKB approximation, for the plasma jet with a boundary in
the form of a tangential discontinuity over the radial coordinate. The
Kelvin-Helmholtz instability develops if plasma flow velocity in the jet
exceeds the maximum Alfven speed at the boundary. The stability of the plasma
jet with a smooth boundary layer is investigated numerically for the basic
modes of MHD oscillations, to which the WKB approximation is inapplicable. A
new ""global"" unstable mode of MHD oscillations has been discovered which,
unlike the Kelvin-Helmholtz instability, exists for any, however weak, plasma
flow velocities.",1002.4700v1
2015-06-30,Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. II- Numerical aspects,"Transverse magnetohydrodynamic (MHD) waves are ubiquitous in the solar
atmosphere and may be responsible for generating the Sun's million-degree outer
atmosphere. However, direct evidence of the dissipation process and heating
from these waves remains elusive. Through advanced numerical simulations
combined with appropriate forward modeling of a prominence flux tube, we
provide the observational signatures of transverse MHD waves in prominence
plasmas. We show that these signatures are characterized by thread-like
substructure, strong transverse dynamical coherence, an out-of-phase difference
between plane-of-the-sky motions and LOS velocities, and enhanced line
broadening and heating around most of the flux tube. A complex combination
between resonant absorption and Kelvin-Helmholtz instabilities (KHI) takes
place in which the KHI extracts the energy from the resonant layer and
dissipates it through vortices and current sheets, which rapidly degenerate
into turbulence. An inward enlargement of the boundary is produced in which the
turbulent flows conserve the characteristic dynamics from the resonance,
therefore guaranteeing detectability of the resonance imprints. We show that
the features described in the accompanying paper (Okamoto et al. 2015) through
coordinated Hinode and IRIS observations match well the numerical results.",1506.09108v1
2016-07-05,Symmetry Breaking of Counter-Propagating Light in a Nonlinear Resonator,"Light is generally expected to travel through isotropic media independent of
its direction. This makes it challenging to develop non-reciprocal optical
elements like optical diodes or circulators, which currently rely on
magneto-optical effects and birefringent materials. Here we present
measurements of non-reciprocal transmission and spontaneous symmetry breaking
between counter-propagating light in dielectric microresonators. The symmetry
breaking corresponds to a resonance frequency splitting that allows only one of
two counter-propagating (but otherwise identical) light waves to circulate in
the resonator. Equivalently, the symmetry breaking can be seen as the collapse
of standing waves and transition to travelling waves within the resonator. We
present theoretical calculations to show that the symmetry breaking is induced
by Kerr-nonlinearity-mediated interaction between the counter-propagating
light. This effect is expected to take place in any dielectric ring-resonator
and might constitute one of the most fundamental ways to induce optical
non-reciprocity. Our findings pave the way for a variety of applications
including all optical switching, nonlinear-enhanced rotation sensing, optically
controllable circulators and isolators, optical flip-flops for photonic
memories as well as exceptionally sensitive power and refractive index sensors.",1607.01194v1
2018-05-01,Pulsar giant pulse: coherent instability near light cylinder,"Giant pulses (GPs) are extremely bright individual pulses of radio pulsar. In
microbursts of Crab pulsar, which is an active GP emitter, zebra-pattern-like
spectral structures are observed, which are reminiscent of the `zebra bands'
that are observed in type IV solar radio flares. However, band spacing linearly
increases with the band center frequency of $\sim5-30$\,GHz. In this study, we
propose that the Crab pulsar GP can originate from the coherent instability of
plasma near a light cylinder. Further, the growth of coherent instability can
be attributed to the resonance observed between the cyclotron-resonant-excited
wave and the background plasma oscillation. The particles can be injected into
the closed-field line regions owing to magnetic reconnection near a light
cylinder. These particles introduce a large amount of free energy that further
causes cyclotron-resonant instability, which grows and amplifies radiative
waves at frequencies close to the electron cyclotron harmonics that exhibit
zebra-pattern-like spectral band structures. Further, these structures can be
modulated by the resonance between the cyclotron-resonant-excited wave and the
background plasma oscillation. In this scenario, the band structures of the
Crab pulsar can be well fitted by a coherent instability model, where the
plasma density of a light cylinder should be $\sim10^{13-15}\,\rm{cm^{-3}}$,
with an estimated gradient of $>5.5\times10^5\,\rm{cm^{-4}}$. This process may
be accompanied by high-energy emissions. Similar phenomena are expected to be
detected in other types of GP sources that have magnetic fields of
$\simeq10^6$\,G in a light cylinder.",1805.00139v2
2018-07-26,Resonant interaction of the electron beam with a synchronous wave in controlled magnetrons for high-current superconducting accelerators,"A simplified analytical model of the resonant interaction of the beam of
Larmor electrons drifting in the crossed constant fields of a magnetron with a
synchronous wave providing a phase grouping of the drifting charge was
developed to optimize the parameters of an rf resonant injected signal driving
the magnetrons for management of phase and power of rf sources with a rate
required for superconducting high-current accelerators. The model, which
considers the impact of the rf resonant signal injected into the magnetron on
the operation of the injection-locked tube, substantiates the recently
developed method of fast power control of magnetrons in the range up to 10 dB
at the highest generation efficiency, with low noise, precise stability of the
carrier frequency, and the possibility of wideband phase control. Experiments
with continuous wave 2.45 GHz, 1 kW microwave oven magnetrons have verified the
correspondence of the behavior of these tubes to the analytical model. A proof
of the principle of the novel method of power control in magnetrons, based on
the developed model, was demonstrated in the experiments. The method is
attractive for high-current superconducting rf accelerators. This paper also
discusses vector methods of power control with the rates required for
superconducting accelerators, the impact of the rf resonant signal injected
into the magnetron on the rate of phase control of the injection-locked tubes,
and a conceptual scheme of the magnetron transmitter with highest efficiency
for high-current accelerators.",1807.10237v1
2020-08-06,Resonant gravitational waves in dynamical Chern-Simons-axion gravity,"In this paper, we consider dynamical Chern-Simons gravity with the
identification of the scalar field coupled though the Pontryagin density with
the axion dark matter, and we discuss the effects of the parametric resonance
on gravitational waves (GWs). When we consider GWs in a coherently oscillating
axion cloud, we confirm that significant resonant amplification of GWs occurs
in a narrow frequency band, and the amplification is restricted to the late
epoch after the passage of the incident waves. We also identify the condition
that an axion cloud spontaneously emits GWs. Once we take into account the
randomness of the spatial phase distribution of the axion oscillations, we find
that the amplification is suppressed compared with the coherent case, but
significant amplification of GWs can still occur. We also examine whether or
not the amplification of GWs is possible in the present universe, taking into
account the history of the universe. We find that resonant amplification is
difficult to be tested from GW observations in the standard scenario of the
axion DM model, in which the axion is the dominant component of DM. However,
there is some parameter window in which the resonant amplification of GWs might
be observed, if the axion is subdominant component of DM, and the axion cloud
formation is delayed until the Hubble rate becomes much smaller than the axion
mass.",2008.02764v2
2020-03-09,Resonant and Scattering States in the $α+α$ System from the Non-Localized Cluster Model,"The non-localized cluster model provides a new perspective on nuclear cluster
effects and has been applied successfully to study cluster structures in
various bound states and quasi-bound states (i.e., long-lived resonant states).
In this work, we extend the application scope of the non-localized cluster
model further to resonant and scattering states. Following the $R$-matrix
theory, the configuration space is divided into the interior and exterior
regions by a large channel radius such that the nuclear forces and the
antisymmetrization effects become negligible between clusters in the exterior
region. In the interior region, the picture of non-localized clustering is
realized mathematically by adopting the Brink-Tohsaki-Horiuchi-Schuck-R\""opke
(Brink-THSR) wave functions as the bases to construct the interior wave
functions. The Bloch-Schr\""odinger equation is used to match the interior wave
functions continuously with the asymptotic boundary conditions of the resonant
and scattering states at the channel radius, which leads eventually to
solutions of the problem. As a first test of the formalism, the low-lying
resonant states of ${}^{8}$Be and the phase shifts of the $\alpha+\alpha$
elastic scattering are studied. The numerical results agree well with the
experimental data, which shows the validity of the theoretical framework.",2003.04313v1
2020-01-28,Two-Path Phonon-Interference Resonance Induces a Stop Band in Silicon Crystal Matrix by Embedded Nanoparticles Array,"In this work, we report a new stop-band formation mechanism by performing the
atomistic Green's function calculation and the wave-packet molecular dynamics
simulation for a system with germanium-nanoparticle array embedded in a
crystalline silicon matrix. When only a single nanoparticle is embedded, the
local resonance, induced through destructive interference between two different
phonon wave paths, gives rise to several sharp and significant transmittance
dips. On the other hand, when the number of embedded nanoparticles further
increases to ten, a stop band with complete phonon reflection is formed due to
the two-path resonance Bragg-like phonon interference. The wave packet
simulations further uncover that the stop band originates from the collective
phonon resonances at the embedded nanoparticles. Compared with the traditional
stop-band formation mechanism that is the single-path Bragg reflection, the
resonance mechanism has a significant advantage in not requiring the strict
periodicity in the embedded nanoparticles array. We also demonstrate that the
stop band can significantly suppress thermal conductance in the low-frequency
regime. Our work provides a robust, scalable. and easily modulable stop-band
formation mechanism. which opens a new degree of freedom for phononics-related
heat control.",2001.10321v1
2020-05-26,Broadband Mie-driven random quasi-phase-matching,"High-quality crystals without inversion symmetry are the conventional
platform to achieve optical frequency conversion via three wave-mixing. In bulk
crystals, efficient wave-mixing relies on phase-matching configurations, while
at the micro- and nano-scale it requires resonant mechanisms that enhance the
nonlinear light-matter interaction. These strategies commonly result in
wavelength-specific performances and narrowband applications. Disordered
photonic materials, made up of a random assembly of optical nonlinear crystals,
enable a broadband tunability in the random quasi-phase-matching (RQPM) regime
and do not require high-quality materials. Here, we combine resonances and
disorder by implementing RQPM in Mie-resonant spheres of a few microns realized
by the bottom-up assembly of barium titanate nano-crystals. The measured second
harmonic generation (SHG) reveals a combination of broadband and resonant wave
mixing, in which Mie resonances drive and enhance the SHG, while the disorder
keeps the phase-matching conditions relaxed. This new phase-matching regime can
be described by a random walk in the SHG complex plane whose step lengths
depend on the local field enhancement within the micro-sphere. Our
nano-crystals assemblies provide new opportunities for tailored phase-matching
at the micro-scale, beyond the coherence length of the bulk crystal. They can
be adapted to achieve frequency conversion from the near-ultraviolet to the
infrared ranges, they are low-cost and scalable to large surface areas.",2005.12609v1
2021-09-02,Resonant triad interactions in stably-stratified uniform shear flow,"We investigate exact and near resonant triad interactions (RTI) in a
two-dimensional stably stratified uniform shear flow confined between two
infinite parallel walls in the absence of viscous and diffusive effects. RTI
occur when three interacting waves satisfy the resonance conditions of the form
$k_1 \pm k_2 = k_3$ and $\omega_1 \pm \omega_2 = \omega_3$ with $k_i$ and
$\omega_i$ being the wavenumber and frequency of the ith wave ($i \in
{1,2,3}$), respectively. The linear stability problem is solved analytically,
which gives the eigenfunctions in the form of the modified Bessel functions. It
is identified that an interaction between two primary modes having the same
frequency $\omega$ but different wavenumbers $k_m$ and $k_n$ produces two
different secondary modes: one time-dependent (superharmonic) mode having
frequency $2\omega$ and wavenumber $k_m +k_n$, and the other time-independent
(subharmonic) mode with $\omega = 0$ and wavenumber $k_m - k_n$. The
differential equation governing the spatial amplitude of the superharmonic mode
is solved numerically as well as analytically using the method of variation of
parameters. It turns out that the linear operator associated with the
differential equation of the superharmonic mode is the same as the linear
stability operator and that the solvability condition of the differential
equation is found to be associated with the existence of RTI. The existence of
resonant triad interactions predicted by the dispersion relation, are justified
by showing the divergence of the spatial amplitude of superharmonic mode.
Various cases of wave interactions in a stably stratified shear flow are
analysed in the presence of a resonant triad for various frequencies and linear
stratifications.",2109.00807v1
2005-05-23,Anisotropy of incommensurate spin and charge fluctuations in detwinned YBa$_2$Cu$_3$O$_{6+δ}$,"Motivated by a recent neutron scattering experiment on detwinned
YBa$_2$Cu$_3$O$_{6+\delta}$ superconductor, we examine the frequency and doping
dependence of the anisotropy in the spin and charge fluctuation arising from
the coupling between the plane and the chain. Starting from the two-dimensional
$t$-$t^{'}$-$J$ model and using the random-phase approximation (RPA), we find a
pronounced anisotropy of the incommensurate (IC) peaks in the spin channel,
namely the peak intensity at the $(\pi\pm\delta,\pi)$ direction is stronger
than that at the $(\pi,\pi\pm\delta)$ direction in a wide frequency range from
$\omega=0.2J$ to the resonance frequency $\omega_r=0.35J$. Above the resonance
frequency, the IC peaks reemerge. Their intensities shift to the diagonal
direction and no anisotropy exists along the two diagonal directions. We find
that this anisotropy is robust with respect to the possible variation of the
RPA correction factor and to the dopings. The charge fluctuation is also found
to be incommensurate for all energies considered and peak at $(0,\delta)$ and
$(\delta,0)$. An anisotropy in its IC peak intensity along the $k_x$ and the
$k_y$ direction exists, but in sharp contrast to the spin channel, the maximum
intensity of the IC peak is along the $k_y$ direction. Moreover, the IC peak in
the charge channel exhibits an upward dispersion, in contrast to the downward
dispersion below the spin resonance frequency for the spin IC peak. We explain
these features based on the effect of the plane-chain coupling on the topology
of the Fermi surface.",0505545v1
2013-06-03,Dynamic nuclear polarization in InGaAs/GaAs and GaAs/AlGaAs quantum dots under non-resonant ultra-low power optical excitation,"We study experimentally the dependence of dynamic nuclear spin polarization
on the power of non-resonant optical excitation in two types of individual
neutral semiconductor quantum dots: InGaAs/GaAs and GaAs/AlGaAs. We show that
the mechanism of nuclear spin pumping via second order recombination of
optically forbidden (''dark'') exciton states recently reported in InP/GaInP
quantum dots [Phys. Rev. B 83, 125318 (2011)] is relevant for material systems
considered in this work. In the InGaAs/GaAs dots this nuclear spin polarization
mechanism is particularly pronounced, resulting in Overhauser shifts up to ~80
micro-eV achieved at optical excitation power ~1000 times smaller than the
power required to saturate ground state excitons. The Overhauser shifts
observed at low-power optical pumping in the interface GaAs/AlGaAs dots are
generally found to be smaller (up to ~40 micro-eV). Furthermore in GaAs/AlGaAs
we observe dot-to-dot variation and even sign reversal of the Overhauser shift
which is attributed to dark-bright exciton mixing originating from
electron-hole exchange interaction in dots with reduced symmetry. Nuclear spin
polarization degrees reported in this work under ultra-low power optical
pumping are comparable to those achieved by techniques such as resonant optical
pumping or above-gap pumping with high power circularly polarized light.
Dynamic nuclear polarization via second-order recombination of ''dark''
excitons may become a useful tool in single quantum dot applications, where
manipulation of the nuclear spin environment or electron spin is required.",1306.0469v1
2015-01-05,Heat Bath Algorithmic Cooling with Spins: Review and Prospects,"Application of multiple rounds of Quantum Error Correction (QEC) is an
essential milestone towards the construction of scalable quantum information
processing devices. However, experimental realizations of it are still in their
infancy. The requirements for multiple round QEC are high control fidelity and
the ability to extract entropy from ancilla qubits. Nuclear Magnetic Resonance
(NMR) based quantum devices have demonstrated high control fidelity with up to
12 qubits. On the other hand, the major challenge in the NMR QEC experiment is
to efficiently supply ancilla qubits in highly pure states at the beginning of
each round of QEC. Purification of qubits in NMR, or in other ensemble based
quantum systems can be accomplished through Heat Bath Algorithmic Cooling
(HBAC). It is an efficient method for extracting entropy from qubits that
interact with a heat bath, allowing cooling below the bath temperature. For
practical HBAC, coupled electron-nuclear spin systems are more promising than
conventional NMR quantum processors, since electron spin polarization is about
$10^3$ times greater than that of a proton under the same experimental
conditions. We provide an overview on both theoretical and experimental aspects
of HBAC focusing on spin and magnetic resonance based systems, and discuss the
prospects of exploiting electron-nuclear coupled systems for the realization of
HBAC and multiple round QEC.",1501.00952v1
2017-11-28,Electron paramagnetic resonance spectroscopy using a single artificial atom,"Electron paramagnetic resonance (EPR) spectroscopy is an important technology
in physics, chemistry, materials science, and biology. Sensitive detection with
a small sample volume is a key objective in these areas, because it is crucial,
for example, for the readout of a highly packed spin based quantum memory or
the detection of unlabeled metalloproteins in a single cell. In conventional
EPR spectrometers, the energy transfer from the spins to the cavity at a
Purcell enhanced rate plays an essential role and requires the spins to be
resonant with the cavity, however the size of the cavity (limited by the
wavelength) makes it difficult to improve the spatial resolution. Here, we
demonstrate a novel EPR spectrometer using a single artificial atom as a
sensitive detector of spin magnetization. The artificial atom, a
superconducting flux qubit, provides advantages both in terms of its quantum
properties and its much stronger coupling with magnetic fields. We have
achieved a sensitivity of $\sim$400 spins/$\sqrt{\mathrm{Hz}}$ with a magnetic
sensing volume around $10^{-14} \lambda^3$ (50 femto-liters). This corresponds
to an improvement of two-order of magnitude in the magnetic sensing volume
compared with the best cavity based spectrometers while maintaining a similar
sensitivity as those spectrometers . Our artificial atom is suitable for
scaling down and thus paves the way for measuring single spins on the nanometer
scale.",1711.10148v1
2019-06-24,"Itinerancy-dependent non-collinear spin textures in SrFeO3, CaFeO3, and CaFeO3/SrFeO3 heterostructures probed via resonant x-ray scattering","Non-collinear, multi-q spin textures can give rise to exotic, topologically
protected spin structures such as skyrmions, but the reason for their formation
over simple single-q structures is not well understood. While lattice
frustration and the Dzyaloshinskii-Moriya interaction are known to produce
non-collinear spin textures, the role of electron itinerancy in multi-q
formation is much less studied. Here we investigated the non-collinear, helical
spin structures in epitaxial films of the perovskite oxides SrFeO3 and CaFeO3
using magnetotransport and resonant soft x-ray magnetic diffraction. Metallic
SrFeO3 exhibits features in its magnetoresistance that are consistent with its
recently proposed multi-q structure. Additionally, the magnetic Bragg peak of
SrFeO3 measured at the Fe L edge resonance energy asymmetrically broadens with
decreasing temperature in its multi-q state. In contrast, insulating CaFeO3 has
a symmetric scattering peak with an intensity 10x weaker than SrFeO3. Enhanced
magnetic scattering at O K edge prepeak energies demonstrates the role of a
negative charge transfer energy and the resulting oxygen ligand holes in the
magnetic ordering of these ferrates. By measuring magnetic diffraction of
CaFeO3/SrFeO3 superlattices with thick CaFeO3 layers, we find that the CaFeO3
helical ordering is coherent across 1 unit cell-thick SrFeO3 layers but not 6
unit cell-thick layers. We conclude that insulating CaFeO3 supports only a
simple single-q helical structure in contrast to metallic SrFeO3 that hosts
multi-q structures. Our results provide important insight into the role of
electron itinerancy in the formation of multi-q spin structures.",1906.09998v1
2021-02-02,Anomalous light-induced broadening of the spin-noise resonance in cesium vapor,"We uncover a highly nontrivial dependence of the spin-noise (SN) resonance
broadening induced by the intense probe beam. The measurements were performed
by probing the cell with cesium vapor at the wavelengths of the transition
${6}^2S_{1/2} \leftrightarrow {6}^2P_{3/2}$ ($\mathrm{D}_2$ line) with the
unresolved hyperfine structure of the excited state. The light-induced
broadening of the SN resonance was found to differ strongly at different slopes
of the $\mathrm{D}_2$ line and, generally, varied nonmonotonically with light
power. We discuss the effect in terms of the phenomenological Bloch equations
for the spin fluctuations and demonstrate that the SN broadening behavior
strongly depends on the relation between the pumping and excited-level decay
rates, the spin precession, and decoherence rates. To reconcile the puzzling
experimental results, we propose that the degree of optical perturbation of the
spin-system is controlled by the route of the excited-state relaxation of the
atom or, in other words, that the act of optical excitation of the atom does
not necessarily break down completely its ground-state coherence and continuity
of the spin precession. Spectral asymmetry of the effect, in this case, is
provided by the position of the ""closed"" transition $F = 4 \leftrightarrow F' =
5$ at the short-wavelength side of the line. This hypothesis, however, remains
to be proven by microscopic calculations.",2102.01679v2
2016-11-28,Three-electron spin qubits,"The goal of this article is to review the progress of three-electron spin
qubits from their inception to the state of the art. We direct the main focus
towards the resonant exchange (RX) qubit and the exchange-only qubit, but we
also discuss other qubit implementations using three electron spins. For each
three-spin qubit we describe the qubit model, the physical realization, the
implementations of single-qubit operations, as well as the read-out and
initialization schemes. Two-qubit gates and decoherence properties are
discussed for the RX qubit and the exchange-only qubit, thereby, completing the
list of requirements for a viable candidate qubit implementation for quantum
computation. We start with describing the full system of three electrons in a
triple quantum dot, then discuss the charge-stability diagram and restrict
ourselves to the relevant subsystem, introduce the qubit states, and discuss
important transitions to other charge states. Introducing the various qubit
implementations, we begin with the exchange-only qubit, followed by the
spin-charge qubit, the hybrid qubit, and the RX qubit, discussing for each the
single-qubit operations, read-out, and initialization methods, whereas the main
focus will be on the RX qubit, whose single-qubit operations are realized by
driving the qubit at its resonant frequency in the microwave range similar to
electron spin resonance. Two different types of two-qubit operations are
presented for the exchange-only and the RX qubit which can be divided into
short-ranged and long-ranged interactions. Both of these interaction types can
be expected to be necessary in a large-scale quantum computer. We also take
into account the decoherence of the qubit through the influence of magnetic
noise as well as dephasing due to charge noise.",1611.09106v1
2017-04-03,Spin-Mechanical Scheme with Color Centers in Hexagonal Boron Nitride Membranes,"Recently observed quantum emitters in hexagonal boron nitride (hBN) membranes
have a potential for achieving high accessibility and controllability thanks to
the lower spatial dimension. Moreover, these objects naturally have a high
sensitivity to vibrations of the hosting membrane due to its low mass density
and high elasticity modulus. Here, we propose and analyze a spin-mechanical
system based on color centers in a suspended hBN mechanical resonator. Through
group theoretical analyses and ab-initio calculation of the electronic and spin
properties of such a system, we identify a spin doublet ground state and
demonstrate that a spin-motion interaction can be engineered which enables
ground state cooling of the mechanical resonator. We also present a toolbox for
initialization, rotation, and readout of the defect spin qubit. As a result the
proposed setup presents the possibility for studying a wide range of physics.
To illustrate its assets, we show that a fast and noise resilient preparation
of a multicomponent cat state and a squeezed state of the mechanical resonator
is possible; the latter is achieved by realizing the extremely detuned,
ultrastrong coupling regime of the Rabi model, where a phonon superradiant
phase transition is expected to occur.",1704.00638v2
2019-08-29,Tuning Single-Atom Electron Spin Resonance in a Vector-Magnetic Field,"Spin resonance of single spin centers bears great potential for chemical
structure analysis, quantum sensing and quantum coherent manipulation.
Essential for these experiments is the presence of a two-level spin system
whose energy splitting can be chosen by applying a magnetic field. In recent
years, a combination of electron spin resonance (ESR) and scanning tunneling
microscopy (STM) has been demonstrated as a technique to detect magnetic
properties of single atoms on surfaces and to achieve sub-${\mu}$eV energy
resolution. Nevertheless, up to now the role of the required magnetic fields
has not been elucidated. Here, we perform single-atom ESR on individual Fe
atoms adsorbed on magnesium oxide (MgO), using a 2D vector magnetic field as
well as the local field of the magnetic STM tip in a commercially available
STM. We show how the ESR amplitude can be greatly improved by optimizing the
magnetic fields, revealing in particular an enhanced signal at large in-plane
magnetic fields. Moreover, we demonstrate that the stray field from the
magnetic STM tip is a versatile tool. We use it here to drive the electron spin
more efficiently and to perform ESR measurements at constant frequency by
employing tip-field sweeps. Lastly, we show that it is possible to perform ESR
using only the tip field, under zero external magnetic field, which promises to
make this technique available in many existing STM systems.",1908.11061v1
2019-11-30,Quadrupole Effects on Nuclear Magnetic Resonance Gyroscopes,"Nuclear magnetic resonance gyroscopes that detect rotation as a shift in the
precession frequency of nuclear spins, have attracted a lot of attentions.
Under a feedback-generated drive, the precession frequency is supposed to be
dependent only on the angular momentum and an applied magnetic field. However,
nuclei with spins larger than 1/2, experience electric quadrupole interaction
with electric field gradients at the cell walls. This quadrupole interaction
shifts the precession frequencies of the nuclear spins, which brings inaccuracy
to the rotation measurement as the quadrupole interaction constant $C_q$ is
difficult to precisely measure. In this work, the effects of quadrupole
interaction on nuclear magnetic resonance gyroscopes is theoretically studied.
We find that, when the constant $C_q$ is small compared to the characteristic
decay rate of the system, as the strength of the feedback-driving field
increases, the quadrupole shift monotonically decreases, regardless of the sign
of $C_q$. In large $C_q$ regime, more than one precession frequency exists, and
the nuclear spins may precess with a single frequency or multi-frequencies
depending on initial conditions. In this regime, with large driving amplitudes,
the nuclear spin can restore the single-frequency-precession. These results are
obtained by solving an effective master equation of the nuclear spins in a
rotating frame, from which both the steady-state solutions and dynamics of the
system are shown.",1912.00216v1
2022-01-11,Resonant Precession of Magnetization and Precession -- Induced DC voltages in FeGaB Thin Films,"Measurements of frequency dependent ferromagnetic resonance (FMR) and spin
pumping driven dc voltage (V_{dc}) are reported for amorphous films of
Fe_{78}Ga_{13}B_{9} (FeGaB) alloy to address the phenomenon of self-induced
inverse spin Hall effect (ISHE) in plain films of metallic ferromagnets. The
V_{dc} signal, which is antisymmetric on field reversal, comprises of symmetric
and asymmetric Lorentzians centered around the resonance field. Dominant role
of thin film size effects is seen in setting the magnitude of static
magnetization, V_{dc} and dynamics of magnetization precession in thinner films
(\leq 8 nm). The film thickness dependence of magnetization parameters
indicates the presence of a magnetically disordered region at the
film-substrate interface, which may promote preferential flow of spins
generated by the precessing magnetization towards the substrate. However, the
V_{dc} signal also draws contributions from rectification effects of a \approx
0.4 \% anisotropic magnetoresistance and a large (\approx 54 n\Omega.m)
anomalous Hall resistivity (AHR) of these films which ride over the effect of
spin-orbit coupling driven spin-to-charge conversion near the film-substrate
interface. We have addressed these data in the framework of the existing
theories of electrodynamics of a ferromagnetic film subjected to
radio-frequency field in a coplanar waveguide geometry. Our estimation of the
self-induced ISHE for the sample with 54 n\Omega.m AHR shows that it may
contribute significantly (\approx 90\%) to the measured symmetric voltage. This
study is expected to be very useful for fully understanding the spin pumping
induced dc voltages in metallic ferromagnets with disordered interfaces and
large anomalous Hall effect.",2201.03739v1
1996-06-06,Resonant interactions in Bénard-Marangoni convection in cylindrical containers,"Convection in a cylindrical container of small aspect ratio is studied. It is
known that when, in addition to buoyancy forces, thermocapillarity effects are
taken into account, resonant interactions of two modes may appear. In the case
of 1:2 resonance amplitude equations are derived, showing the existence of a
stable heteroclinic orbit and rotating waves, until now not observed
experimentally.",9605016v1
1999-02-01,Quantum resonances and decay of a chaotic fractal repeller observed using microwaves,"The quantum resonances of classically chaotic n-disk geometries were studied
experimentally utilizing thin 2-D microwave geometries. The experiments yield
the frequencies and widths of low-lying resonances, which are compared with
semiclassical calculations. The longtime or small energy behavior of the
wave-vector auto-correlation gives information about the quantum decay rate,
which is in good agreement with that obtained from classical scattering theory.
The intermediate energy behavior shows non-universal oscillations determined by
periodic orbits.",9902002v2
2001-04-12,Fano and Kondo resonance in electronic current through nanodevices,"Electronic transport through a quantum dot strongly coupled to electrodes is
studied within a model with two conduction channels. It is shown that multiple
scattering and interference of transmitted waves through both channels lead to
Fano resonance associated with Kondo resonance. Interference effects are also
pronouncedly seen in transport through the Aharonov-Bohm ring with the Kondo
dot, where the current characteristics continuously evolve with the magnetic
flux.",0104217v3
2001-06-18,Mechanism of pseudogap probed by a local impurity,"The response to a local strong non-magnetic impurity in the pseudogap phase
is examined in two distinctly different scenarios: phase-fluctuation (PF) of
pairing field and d-density-wave (DDW) order. In the PF scenario, the resonance
state is generally double-peaked near the Fermi level, and is abruptly
broadened by vortex fluctuations slightly above the transition temperature. In
the DDW scenario, the resonance is single-peaked and remains sharp up to
gradual intrinsic thermal broadening, and the resonance energy is analytically
determined to be at minus of the chemical potential.",0106327v4
2001-11-15,Stochastic resonance in a model of opinion formation on small-world networks,"We analyze the phenomenon of stochastic resonance in an Ising-like system on
a small-world network. The system, which is subject to the combined action of
noise and an external modulation, can be interpreted as a stylized model of
opinion formation by imitation under the effects of a ``fashion wave''. Both
the amplitude threshold for the detection of the external modulation and the
width of the stochastic-resonance peak show considerable variation as the
randomness of the underlying small-world network is changed.",0111289v1
2002-05-03,Spatial Solitons and Anderson Localization,"Stochastic (Anderson) localization is the spatial localization of the
wave-function of quantum particles in random media. We show, that a
corresponding phenomenon can stabilize spatial solitons in optical resonators:
spatial solitons in resonators with randomly distorted mirrors are more stable
than in perfect mirror resonators. We demonstrate the phenomenon numerically,
by investigating solitons in lasers with saturable absorber, and analytically
by deriving and analyzing coupled equations of spatially coherent and
incoherent field components.",0205061v2
2003-05-17,Resonant scattering of solitons,"We study the scattering of solitons in the nonlinear Schroedinger equation on
local inhomogeneities which may give rise to resonant transmission and
reflection. In both cases, we derive resonance conditions for the soliton's
velocity. The analytical predictions are tested numerically in regimes
characterized by various time scales. Special attention is paid to intermode
interactions and their effect on coherence, decoherence and dephasing of
plane-wave modes which build up the soliton.",0305410v1
2006-08-01,Coherent magnetotransport spectroscopy in an edge-blocked double quantum wire with window and resonator coupling,"We propose an electronic double quantum wire system that contains a pair of
edge blocking potential and a coupling element in the middle barrier between
two ballistic quantum wires. A window and a resonator coupling control between
the parallel wires are discussed and compared for the enhancement of the
interwire transfer processes in an appropriate magnetic field. We illustrate
the results of the analysis by performing computational simulations on the
conductance and probability density of electron waves in the window and
resonator coupled double wire system.",0608027v1
1998-01-05,Noisy Spherical Resonant Detector of Gravitational Waves: Veto on the Longitudinal Part of the Signal,"The equations of a resonant sphere in interaction with $N$ secondary radial
oscillators (transducers) on its surface have been found in the context of
Lagrangian formalism. It has been shown the possibility to exert a veto against
spurious events measuring the longitudinal component of a signal. Numerical
simulations has been performed, which take into account thermal noise between
resonators and the sphere surface, for a particular configuration of the
transducers.",9801006v1
2005-04-22,Test of constancy of speed of light with rotating cryogenic optical resonators,"A test of Lorentz invariance for electromagnetic waves was performed by
comparing the resonance frequencies of two optical resonators as a function of
orientation in space. In terms of the Robertson-Mansouri-Sexl theory, we obtain
$\beta-\delta-1/2=(+0.5\pm 3\pm 0.7) E-10$, a ten-fold improvement compared to
the previous best results. We also set a first upper limit for a so far unknown
parameter of the Standard Model Extension test theory,
$|(\tilde{\kappa}_{e-})^{ZZ}| < 2\cdot E-14$.",0504109v1
1992-06-03,Resonance Scattering Phase Shifts in a 2-d Lattice Model,"We study a simple 2-d model representing two fields with different mass and a
3-point coupling term. The phase shift in the resonating 2-particle channel is
determined from the energy spectrum obtained in Monte Carlo simulations on
finite lattices. Masses and wave function renormalization constants of the
fields as well as mass and width of the resonance are determined and discussed.
The representation of scattering states in terms of the considered operators is
analysed.",9206004v1
1994-11-29,$τ\to πK ν$ Decay and $πK$ Scattering,"Using chiral low energy theorems and elastic unitarity assumption, the
$\tau\to\pi K \nu $ decay is investigated. The vector and scalar $\pi K$ form
factors are calculated. It is found that the $\pi K$ spectrum is dominated by
the $K^*$ resonance. By measuring the forward-backward asymmetry, it is shown
that the S wave $\pi K$ phase shift can be determined near the $K^{*}$
resonance region. The calculated branching ratio and resonance parameters are
in good agreement with experiments.",9411423v1
1998-12-31,Gamma photons from parametric resonance in neutron stars,"Shock waves in cold nuclear matter, e.g. those induced by a collision of two
neutron stars, can generate a large number of gamma photons via parametric
resonance. We study the resonant production of gamma rays inside a shocked
neutron star and discuss the possible astrophysical consequences of this
phenomenon.",9812534v2
2003-01-13,Variation of the relative yield of charged and neutral B mesons across the Upsilon(4S) resonance,"It is shown that the ratio of the production rates of the pairs (B+ B-) and
(B0 anti-B0) should experience a substantial and rapid variation with energy
within the width of the Upsilon(4S) resonance, crossing the value of one near
the center of the resonance. This behavior is due to an interference of the
rapidly changing with energy Breit-Wigner phase with the phase introduced in
the wave function of charged mesons by their Coulomb interaction.",0301076v1
2006-11-20,Photon - Axion Conversion Cross Sections in a Resonant Cavity,"Photon - axion conversions in the resonant cavity with the lowest mode are
considered in detail by the Feynman diagram method. The differential cross
sections are presented and numerical evaluations are given. It is shown that
there is a resonant conversion for the considered process, in which the
conversion cross sections are much larger than those of the wave guide in the
same conditions. Some estimates for experimental conditions are given from our
results.",0611258v1
2007-01-27,Partial waves and large $N_C$ resonance sum rules,"Using $1/N_C$ expansion and dispersion theory techniques, without relying on
any explicit resonance lagrangian, we generalize the KSRF relation beyond the
leading chiral order. Two sum rules for the low energy constants $L_2$, $L_3$
and a new relation between resonance couplings are derived. A rather detailed
examination to the new relation is also given.",0701232v2
2006-07-24,Above Barrier Dirac Multiple Scattering and Resonances,"We extend an above barrier analysis made with the Schrodinger equation to the
Dirac equation. We demonstrate the perfect agreement between the barrier
results and back to back steps. This implies the existence of multiple (indeed
infinite) reflected and transmitted wave packets. These packets may be well
separated in space or partially overlap. In the latter case interference
effects can occur. For the extreme case of total overlap we encounter
resonances. The conditions under which resonance phenomena can be observed is
discussed and illustrated by numerical calculations.",0607175v1
2004-08-26,Schrödinger operators with complex-valued potentials and no resonances,"In dimension $d\geq 3$, we give examples of nontrivial, compactly supported,
complex-valued potentials such that the associated Schr\""odinger operators have
no resonances. If $d=2$, we show that there are potentials with no resonances
away from the origin. These Schr\""odinger operators are isophasal and have the
same scattering phase as the Laplacian on $\Real^d$. In odd dimensions $d\geq
3$ we study the fundamental solution of the wave equation perturbed by such a
potential. If the space variables are held fixed, it is super-exponentially
decaying in time.",0408052v1
2004-10-20,Fano resonance in quadratic waveguide arrays,"We study resonant light scattering in arrays of channel optical waveguides
where tunable quadratic nonlinearity is introduced as nonlinear defects by
periodic poling of single (or several) waveguides in the array. We describe
novel features of wave scattering that can be observed in this structure and
show that it is a good candidate for the first observation of Fano resonance in
nonlinear optics.",0410041v2
2005-07-14,Enhanced soliton transport in quasi-periodic lattices with short-range aperiodicity,"We study linear transmission and nonlinear soliton transport through
quasi-periodic structures, which profiles are described by multiple modulation
frequencies. We show that resonant scattering at mixed-frequency resonances
limits transmission efficiency of localized wave packets, leading to radiation
and possible trapping of solitons. We obtain an explicit analytical expression
for optimal quasi-periodic lattice profiles, where additional aperiodic
modulations suppress mixed-frequency resonances, resulting in dramatic
enhancement of soliton mobility. Our results can be applied to the design of
photonic waveguide structures, and arrays of magnetic micro-traps for atomic
Bose-Einstein condensates.",0507027v1
2005-01-24,"Physics at ELSA, achievements and future","At ELSA interesting results on baryon resonances have been obtained by the
CB-ELSA, the CBELSA/TAPS and the SAPHIR collaborations. New resonances were
found, in particular a new $\rm D_{15}(2070)$ decaying into $p\eta$, was
recently observed by the CB-ELSA experiment. The availability of a polarized
beam and a polarized target did allow to measure the GDH sum rule up to 2.9
GeV. In the future double polarization experiments will be performed using the
Crystal Barrel detector together with new forward detector components. These
polarization observables will provide important additional information for the
partial wave analyses performed to extract the contributing resonances and
their parameters from the data.",0501024v1
1995-09-04,Updated resonance photo-decay amplitudes to 2 GeV,"We present the results of an energy-dependent and set of single-energy
partial-wave analyses of single-pion photoproduction data. These analyses
extend from threshold to 2 GeV in the laboratory photon energy, and update our
previous analyses to 1.8 GeV. Photo-decay amplitudes are extracted for the
baryon resonances within this energy range. We consider two photoproduction sum
rules and the contributions of two additional resonance candidates found in our
most recent analysis of $\pi N$ elastic scattering data. Comparisons are made
with previous analyses.",9509005v1
1999-04-01,Evidence for the fourth P11 resonance predicted by the constituent quark model,"It is pointed out that the third of five low-lying P11 states predicted by a
constituent quark model can be identified with the third of four states in a
solution from a three-channel analysis by the Zagreb group. This is one of the
so-called ``missing'' resonances, predicted at 1880 MeV. The fit of the Zagreb
group to the pi N -> eta N data is the crucial element in finding this fourth
resonance in the P11 partial wave.",9904005v2
2000-10-18,The NN Phase Shifts <3 GeV and Resonance Features,"Solutions SP00, SM00 and FA00 of nucleon-nucleon (NN) phase shift analyzes by
Arndt et al. are used in optical model studies. The partial waves, single
channels J.leq.7 and coupled channels J.leq.6, are scrutinized. The radial
probability distributions and losses of flux are used to identify the known
Delta and N* resonances as well as anticipated other structures. The energy
interval extends to 3 GeV.",0010058v1
2004-12-21,Monopole and quadrupole polarization effects on the alpha-particle description of $^{8}$Be,"We investigate the effect of monopole and quadrupole modes on the elastic
alpha-alpha resonance structure of $^{8}$Be. To this end we make a fully
microscopic coupled channels calculation with three coupled channels, using the
Algebraic Model. The continuum spectrum and wave functions are analyzed in
terms of the individual channels to understand the nature of the resonances. It
is shown that both monopole and quadrupole modes have a non-negligible effect
on the resonances in the alpha-alpha continuum.",0412086v1
2002-07-25,Collision rates in near-resonant optical lattices,"We present a simple method to calculate the binary collision rate between
atoms in near-resonant optical lattices. The method is based on the Monte Carlo
wave function simulations and the collision rate is obtained by monitoring the
quantum flux beyond the average distance between the atoms. To illustrate the
usefulness of the method, we calculate the collision rates for a wide range of
occupation densities and various modulation depths of the lattice. The method
presented here combined with the semiclassical calculations accounting for
intra-well collisions can simplify the study of the effects of binary
collisions on the dynamics of atomic clouds trapped in near-resonant optical
lattices.",0207105v1
2003-05-27,Effects of boundary roughness on a Q-factor of whispering-gallery-mode lasing microdisk cavities,"We perform numerical studies of the effect of sidewall imperfections on the
resonant state broadening of the optical microdisk cavities for lasing
applications. We demonstrate that even small edge roughness causes a drastic
degradation of high-Q whispering gallery (WG) mode resonances reducing their
Q-values by many orders of magnitude. At the same time, low-Q WG resonances are
rather insensitive to the surface roughness. The results of numerical
simulation obtained using the scattering matrix technique, are analyzed and
explained in terms of wave reflection at a curved dielectric interface combined
with the examination of Poincare surface of sections in the classical ray
picture.",0305111v1
2004-06-07,Efficient excitation of cavity resonances of subwavelength metallic gratings,"One dimensional rectangular metallic gratings enable enhanced transmission of
light for specific resonance frequencies. Two kinds of modes participating to
enhanced transmission have already been demonstrated : (i) waveguide modes and
(ii) surface plasmon polaritons (SPP). Since the original paper of Hessel and
Oliner \cite{hessel} pointing out the existence of (i), no progress was made in
their understanding. We present here a carefull analysis, and show that the
coupling between the light and such resonances can be tremendously improved
using an {\it evanescent} wave. This leads to enhanced localisation of light in
cavities, yielding, in particular, to a very selective light transmission
through these gratings.",0406028v1
2004-11-24,Shape resonances in nested diffraction gratings,"The diffraction problem of a plane wave impinging on a grating formed by
nested cavities is solved by means of the modal method, for $s$ and $p$
polarization modes. The cavities are formed by perfectly conducting sheets that
describe rectangular profiles. The electromagnetic response of the grating is
analyzed, paying particular attention to the generation of resonances within
the structure. The dependence of the resonances on the geometrical parameters
of the grating is studied, and results of far and near field are shown. The
results are checked and compared with those available in the literature for
certain limit cases.",0411223v1
2005-03-31,High-contrast dark resonance on the D2 - line of 87Rb in a vapor cell with different directions of the pump - probe waves,"We propose a novel method enabling to create a high-contrast dark resonance
in the 87Rb vapor D2-line. The method is based on an optical pumping of atoms
into the working states by a two-frequency, linearly-polarized laser radiation
propagating perpendicularly to the probe field. This new scheme is compared to
the traditional scheme involving the circularly-polarized probe beam only, and
significant improvement of the dark resonance parameters is found. Qualitative
considerations are confirmed by numerical calculations.",0503246v2
2005-06-01,Multi-electron giant dipole resonances of atoms in crossed electric and magnetic fields,"Multi-electron giant dipole resonances of atoms in crossed electric and
magnetic fields are investigated. Stationary configurations corresponding to a
highly symmetric arrangement of the electrons on a decentered circle are
derived, and a normal-mode stability analysis is performed. A classification of
the various modes, which are dominated either by the magnetic or Coulomb
interactions, is provided. A six-dimensional wave-packet dynamical study, based
on the MCTDH approach, is accomplished for the two-electron resonances,
yielding in particular lifetimes of more than 0.1 $\mu$s for strong electric
fields.",0506007v1
2005-12-23,Induced radiation processes in single-bubble sonoluminescence,"According to the recent revision of the theory of thermal radiation, thermal
black-body radiation has an induced origin. We show that in single-bubble
sonoluminescence thermal radiation is emitted by a spherical resonator,
coincident with the sonoluminescing bubble itself, instead of the ensemble of
elementary resonators emitting thermal black-body radiation in the case of open
gaseous media. For a given wavelength, the diameter of the resonator is fixed,
and this explains the very high constancy in phase of light flashes from the
sonoluminesing bubble, which is better than the constancy of period of a
driving acoustic wave.",0512228v1
2006-10-03,Enhanced Transmission and Reflection of Femtosecond Pulses by a Single Slit,"We show that a physical mechanism responsible for the enhanced transmission
and reflection of femtosecond pulses by a single subwavelength nanoslit in a
thick metallic film is the Fabry-Perot-like resonant excitation of stationary,
quasistationary and nonstationary waves inside the slit, which leads to the
field enhancement inside and around the slit. The mechanism is universal for
any pulse-scatter system, which supports the stationary resonances. We point
out that there is a pulse duration limit below which the slit does not support
the intraslit resonance.",0610019v1
1999-09-15,Repulsion of Resonance States and Exceptional Points,"Level repulsion is associated with exceptional points which are square root
singularities of the energies as functions of a (complex) interaction
parameter. This is also valid for resonance state energies. Using this concept
it is argued that level anti-crossing (crossing) must imply crossing
(anti-crossing) of the corresponding widths of the resonance states. Further,
itis shown that an encircling of an exceptional point induces a phase change of
one wave function but not of the other. An experimental setup is discussed
where this phase behaviour which differs from the one encountered at a diabolic
point can be observed.",9909047v1
2002-10-26,The quantum mechanical geometric phase of a particle in a resonant vibrating cavity,"We study the general-setting quantum geometric phase acquired by a particle
in a vibrating cavity. Solving the two-level theory with the rotating-wave
approximation and the SU(2) method, we obtain analytic formulae that give
excellent descriptions of the geometric phase, energy, and wavefunction of the
resonating system. In particular, we observe a sudden $\pi$-jump in the
geometric phase when the system is in resonance. We found similar behaviors in
the geometric phase of a spin-1/2 particle in a rotating magnetic field, for
which we developed a geometrical model to help visualize its evolution.",0210182v1
2004-11-15,Electric circuit networks equivalent to chaotic quantum billiards,"We formulate two types of electric RLC resonance network equivalent to
quantum billiards. In the network of inductors grounded by capacitors squared
resonant frequencies are eigenvalues of the quantum billiard. In the network of
capacitors grounded by inductors squared resonant frequencies are given by
inverse eigen values of the billiard. In both cases local voltages play role of
the wave function of the quantum billiard. However as different from quantum
billiards there is a heat power because of resistance of the inductors. In the
equivalent chaotic billiards we derive the distribution of the heat power which
well describes numerical statistics.",0411100v1
2007-06-21,First Order Superfluid to Bose Metal Transition in Systems with Resonant Pairing,"Systems showing resonant superfluidity, driven by an exchange coupling of
strength $g$ between uncorrelated pairs of itinerant fermions and tightly bound
ones, undergo a first order phase transition as $g$ increases beyond some
critical value $g_c$. The superfluid phase for $g \leq g_c$ is characterized by
a gap in the fermionic single particle spectrum and an acoustic sound-wave like
collective mode of the bosonic resonating fermion pairs inside this gap. For
$g>g_c$ this state gives way to a phase uncorrelated bosonic liquid with a
$q^2$ spectrum.",0706.3143v1
2007-10-22,Upper and lower bounds on resonances for manifolds hyperbolic near infinity,"For a conformally compact manifold that is hyperbolic near infinity and of
dimension $n+1$, we complete the proof of the optimal $O(r^{n+1})$ upper bound
on the resonance counting function, correcting a mistake in the existing
literature. In the case of a compactly supported perturbation of a hyperbolic
manifold, we establish a Poisson formula expressing the regularized wave trace
as a sum over scattering resonances. This leads to an $r^{n+1}$ lower bound on
the counting function for scattering poles.",0710.3894v2
2007-11-23,Resonant Fibonacci Quantum Well Structures,"We propose a resonant one-dimensional quasicrystal, namely, a multiple
quantum well (MQW) structure satisfying the Fibonacci-chain rule with the
golden ratio between the long and short inter-well distances. The resonant
Bragg condition is generalized from the periodic to Fibonacci MQWs. A
dispersion equation for exciton-polaritons is derived in the two-wave
approximation, the effective allowed and forbidden bands are found. The
reflection spectra from the proposed structures are calculated as a function of
the well number and detuning from the Bragg condition.",0711.3769v1
2007-12-19,Real stabilization method for nuclear single particle resonances,"We develop the real stabilization method within the framework of the
relativistic mean field (RMF) model. With the self-consistent nuclear
potentials from the RMF model, the real stabilization method is used to study
single-particle resonant states in spherical nuclei. As examples, the energies,
widths and wave functions of low-lying neutron resonant states in $^{120}$Sn
are obtained. These results are compared with those from the scattering phase
shift method and the analytic continuation in the coupling constant approach
and satisfactory agreements are found.",0712.3087v1
2008-05-13,Collisionless Absorption of Intense Laser Beams by Anharmonic Resonance,"Two decades after the invention of chirped pulse amplification the physical
mechanism of collisionless absorption of intense laser radiation in overdense
matter is still not sufficiently well understood. We show that anharmonic
resonance in the self-generated plasma potential of the single plasma layers
(cold plasma model) or of the individual electrons (warm plasma), respectively,
constitutes the leading physical mechanism of collisionless absorption in an
overdense plasma. Analogously to collisions, resonance provides for the finite
phase shift of the free electron current relative to the driving laser field
which is compulsory for energy transfer from the laser beam to any medium. An
efficient new scenario of wave breaking is also indicated.",0805.1815v1
2008-08-12,Resonant Transmission of Electromagnetic Fields through Subwavelength Zero-$ε$ Slits,"We theoretically investigate the transmission of electromagnetic radiation
through a metal plate with a zero-$\epsilon$ metamaterial slit, where the
permittivity tends towards zero over a given bandwidth. Our analytic results
demonstrate that the transmission coefficient can be substantial for a broad
range of slit geometries, including subwavelength widths that are many
wavelengths long. This novel resonant effect has features quite unlike the
Fabry-P\'{e}rot-like resonances that have been observed in conductors with deep
channels. We further reveal that these high impedance ultranarrow
zero-$\epsilon$ channels can have significantly {\it greater} transmission
compared to slits with no wave impedance difference across them.",0808.1635v1
2008-10-28,Free-space Excitation of Resonant Cavities formed from Cloaking Metamaterial,"We propose a new class of resonant electromagnetic structures, and study
their response to free-space illumination. The structures consist of partial
cylindrical shells that have cloaking material properties proposed by Pendry et
al. These metamaterial shells have apertures that allow the propagation of
incident irradiation into an interior resonant cavity. We use full wave
time-harmonic analysis to study the field distribution inside the cavity, and
show that an analogue of Whispering Gallery Modes (WGMs) can be efficiently
excited via free-space illumination.",0810.4961v1
2009-09-10,Optical response of finite-length carbon nanotubes,"Optical response of finite-length metallic carbon nanotubes is calculated
including effects of induced edge charges in a self-consistent manner. The
results show that the main resonance corresponding to excitation of the
fundamental plasmon mode with wave vector $\pi/l$ with $l$ being the tube
length is quite robust and unaffected. This arises because the strong electric
field associated with edge charges is screened and decays rapidly inside the
nanotube. For higher-frequency resonances, the field starts to be mixed and
tends to shift resonances to higher frequencies.",0909.1908v1
2009-10-09,Entanglement and parametric resonance in driven quantum systems,"We study the relationship between entanglement and parametric resonance in a
system of two coupled time-dependent oscillators. As a measure of bipartite
entanglement, we calculate the linear entropy for the reduced density operator,
from which we study the entanglement dynamics. In particular, we find that the
bipartite entanglement increases in time up to a maximal mixing scenario, when
the set of auxiliary dynamical parameters are under parametric resonance.
Moreover, we obtain a closed relationship between the correlations in the
ground state, the localisation of the Wigner function in phase space, and the
localisation of the wave function of the total system.",0910.1600v1
2009-12-11,Magneto-optical Feshbach resonance: Controlling cold collision with quantum interference,"We propose a method of controlling two-atom interaction using both magnetic
and laser fields. We analyse the role of quantum interference between magnetic
and optical Feshbach resonances in controlling cold collision. In particular,
we demonstrate that this method allows us to suppress inelastic and enhance
elastic scattering cross sections. Quantum interference is shown to modify
significantly the threshold behaviour and resonant interaction of ultracold
atoms. Furthermore, we show that it is possible to manipulate not only the
spherically symmetric s-wave interaction but also the anisotropic higher
partial-wave interactions which are particularly important for high temperature
superfluid or superconducting phases of matter.",0912.2170v2
2010-05-19,Emerging beam resonances in atom diffraction from a reflection grating,"We report on the observation of emerging beam resonances, well known as
Rayleigh-Wood anomalies and threshold resonances in photon and electron
diffraction, respectively, in an atom-optical diffraction experiment.
Diffraction of He atom beams reflected from a blazed ruled grating at grazing
incidence has been investigated. The total reflectivity of the grating as well
as the intensities of the diffracted beams reveal anomalies at the Rayleigh
angles of incidence, i.e., when another diffracted beam merges parallel to the
grating surface. The observed anomalies are discussed in terms of the classical
wave-optical model of Rayleigh and Fano.",1005.3467v1
2010-05-28,Electromagnetic and phonon modes for superfluid He-4 with a disk resonator,"We find the distribution of the electromagnetic field inside and outside a
dielectric disk resonator placed in He-II. It is shown that this field consists
of a collection of ""circular"" (c-) photons. The wave function \Psi_c of a
c-phonon for the He-II + disk system is calculated in the zero-order
approximation in interaction. Due to the symmetry of the problem, the structure
of \Psi_c is such that a c-phonon possesses, similarly to a c-photon of the
resonator, a definite energy and an angular momentum with respect to the disk
axis, but it does not possess a definite momentum in the disk plane.",1005.5282v1
2010-09-16,Universal Optical Frequency Comb,"We demonstrate that whispering gallery mode resonators can be utilized to
generate optical frequency combs based on four wave mixing process at virtually
any frequency that lies in the transparency window of the resonator host
material. We show theoretically how the morphology of the resonator can be
engineered to produce a family of spectrally equidistant modes with anomalous
group velocity dispersion appropriate for the comb generation. We present
experimental results for a frequency comb centered at 794 nm to support our
theoretical findings.",1009.3286v1
2010-10-18,Study of the double non linear quantum resonances in diatomic molecules,"We study the quantum dynamics of diatomic molecule driven by a circularly
polarized resonant electric field. We look for a quantum effect due to
classical chaos appearing due to the overlapping of nonlinear resonances
associated to the vibrational and rotational motion. We solve the Schr\""odinger
equation associated with the wave function expanded in term of proper
stationary states, $|n>\otimes|lm>$ (vibrational$\otimes$angular momentum
states). Looking for quantum-classic correspondence, we consider the Liouville
dynamics in the two dimensional phase space defined by the coherent -like state
of vibrational states, and it is found some similarities when the quantum
dynamics is pictured in terms of number and phase operators.",1010.3627v1
2010-10-28,A single fermion in a Bose Josephson Junction,"We consider the tunneling properties of a single fermionic impurity immersed
in a Bose-Einstein condensate in a double-well potential. For strong
boson-fermion interaction, we show the existence of a tunnel resonance where a
large number of bosons and the fermion tunnel simultaneously. We give
analytical expressions for the lineshape of the resonance using degenerate
Brillouin-Wigner theory. We finally compute the time-dependent dynamics of the
mixture. Using the fermionic tunnel resonances as beam splitter for
wave-functions, we construct a Mach-Zehnder interferometer that allows complete
population transfer from one well to the other by tilting the double-well
potential and only taking into account the fermion's tunnel properties.",1010.5979v1
2011-01-07,Interaction of the Electromagnetic p-Wave with Thin Metal Film in the Field of Resonant Frequencies,"It is shown that for thin metallic films thickness of which does not exceed
thickness of skin layer, the problem allows analytical solution. In the field
of resonant frequencies the analysis of dependence of coefficients of
transmission, reflection and absorbtion on an electromagnetic wave is carried
out. Dependence on pitch angle, thickness of the layer and coefficient of
specular reflection and on effective electron collision frequency is carried
out. The formula for contactless determination (calculation) of a thickness of
a film by observable resonant frequencies is deduced.",1101.1453v1
2011-02-08,Space-time resonances,"This article is a short exposition of the space-time resonances method. It
was introduced by Masmoudi, Shatah, and the author, in order to understand
global existence for nonlinear dispersive equations, set in the whole space,
and with small data. The idea is to combine the classical concept of
resonances, with the feature of dispersive equations: wave packets propagate at
a group velocity which depends on their frequency localization. The analytical
method which follows from this idea turns out to be a very general tool.",1102.1695v1
2011-03-22,Resonant Photoelectron Diffraction with circularly polarized light,"Resonant angle scanned x-ray photoelectron diffraction (RXPD) allows the
determination of the atomic and magnetic structure of surfaces and interfaces.
For the case of magnetized nickel the resonant L2 excitation with circularly
polarized light yields electrons with a dichroic signature from which the
dipolar part may be retrieved. The corresponding L2MM and L3MM Auger electrons
carry different angular momenta since their source waves rotate the dichroic
dipole in the electron emission patterns by distinct angles.",1103.4280v1
2011-06-09,Wave approach for the resonances of rectangular and triangular membranes,"This study develops a ray technique for determining the resonance frequencies
of triangular membranes. The technique is demonstrated for homogenous
rectangular and triangular membranes with fixed boundaries. Where possible, the
results are compared with exact calculations. The membrane resonances are
calculated using an equivalent string whose length is proportional to the
reciprocal of the length of closed paths starting from an arbitrary point
within the membrane. Closed paths are ray paths which arrive back at the
starting point going in the same direction.",1106.1829v1
2011-07-29,Sub-kHz-level relative stabilization of an intracavity doubled continuous wave optical parametric oscillator using Pound-Drever-Hall scheme,"We report the relative frequency stabilization of an intracavity frequency
doubled singly resonant optical parametric oscillator on a Fabry-Perot\'etalon.
The red/orange radiation produced by the frequency doubling of the intracavity
resonant idler is stabilized using the Pound-Drever-Hall locking technique. The
relative frequency noise of this orange light, when integrated from 1 Hz to 50
kHz, corresponds to a standard deviation of 700 Hz. The frequency noise of the
pump laser is shown experimentally to be transferred to the non resonant signal
beam.",1107.5906v1
2011-07-30,Electromagnetic response of a metamaterial with field-gradient-induced transparency,"We investigate a dynamically controllable electromagnetically induced
transparency-like metamaterial. The unit structure of the metamaterial consists
of a low-quality-factor resonator and a high-quality-factor resonator. The
field gradient of the incident electromagnetic wave in the transverse direction
induces coupling between these two types of resonators and causes a
transparency phenomenon. We present the simulation and experimental results for
the dynamic control of the electromagnetic response.",1108.0054v1
2011-11-05,Optical antennas as nanoscale resonators,"Recent progress in nanotechnology has enabled us to fabricate subwavelength
architectures that function as antennas for improving the exchange of optical
energy with nanoscale matter. We describe the main features of optical antennas
for enhancing quantum emitters and review designs that increase the spontaneous
emission rate by orders of magnitude from the ultraviolet up to the
near-infrared spectral range. To further explore how optical antennas may lead
to unprecedented regimes of light-matter interaction, we draw a relationship
between metal nanoparticles, radio-wave antennas and optical resonators. Our
analysis points out how optical antennas may function as nanoscale resonators
and how these may offer unique opportunities with respect to state-of-the-art
microcavities.",1111.1302v1
2012-07-04,Coupled $\ell$-wave confinement-induced resonances in cylindrically symmetric waveguides,"A semi-analytical approach to atomic waveguide scattering for harmonic
confinement is developed taking into account all partial waves. As a
consequence $\ell$-wave confinement-induced resonances are formed being coupled
to each other due to the confinement. The corresponding resonance condition is
obtained analytically using the $K$-matrix formalism. Atomic scattering is
described by transition diagrams which depict all relevant processes the atoms
undergo during the collision. Our analytical results are compared to
corresponding numerical data and show very good agreement.",1207.0989v3
2012-10-01,Three-particle decays of light nuclei resonances,"We have studied the three-particle decay of 12C, 9Be and 6Be resonances.
These nuclei have been described as three-body systems by means of the complex
scaled hyperspherical adiabatic expansion method. The short-distance part of
the wave-function is responsible for the energies whereas the information
related to the observable decay properties is contained at large distances,
which must be computed accurately. As an illustration we show the results for
the angular distribution of 9Be and 6Be resonances.",1210.0319v1
2012-12-07,Complex masses of resonances and the Cornell potential,"Physical properties of the Cornell potential in the complex-mass scheme are
investigated. Two exact asymptotic solutions of relativistic wave equation for
the coulombic and linear components of the potential are used to derive the
resonance complex-mass formula. The centered masses and total widths of the
$\rho$-family resonances are calculated.",1212.1737v2
2012-12-21,PT-symmetry with a system of three-level atoms,"We show that a vapor of multilevel atoms driven by far-off resonant laser
beams, with possibility of interference of two Raman resonances, is highly
efficient for creating parity-time (PT) symmetric profiles of the probe-field
refractive index, whose real part is symmetric and imaginary part is
anti-symmetric in space. The spatial modulation of the susceptibility is
achieved by proper combination of standing-wave strong control fields and of
Stark shifts induced by a far-off-resonance laser field. As particular examples
we explore a mixture of isotopes of Rubidium atoms and design a PT-symmetric
lattice and a parabolic refractive index with a linear imaginary part.",1212.5486v1
2013-03-15,A silicon electromechanical photodetector,"Opto-mechanical systems have enabled wide-band optical frequency conversion
and multi-channel all-optical radio frequency amplification. Realization of an
on-chip silicon communication platform is limited by photodetectors needed to
convert optical information to electrical signals for further signal
processing. In this paper we present a coupled silicon micro-resonator, which
converts near-IR optical intensity modulation at 174.2MHz and 1.198GHz into
motional electrical current. This device emulates a photodetector which detects
intensity modulation of continuous wave laser light in the
full-width-at-half-maximum bandwidth of the mechanical resonance. The resonant
principle of operation eliminates dark current challenges associated with
convetional photodetectors.",1303.3900v1
2013-04-03,Slow light enhanced correlated photon pair generation in photonic-crystal coupled-resonator optical waveguides,"We demonstrate the generation of quantum-correlated photon pairs from a Si
photonic-crystal coupled-resonator optical waveguide. A slow-light supermode
realized by the collective resonance of high-Q and small-mode-volume
photonic-crystal cavities successfully enhanced the efficiency of the
spontaneous four-wave mixing process. The generation rate of photon pairs was
improved by two orders of magnitude compared with that of a photonic-crystal
line defect waveguide without a slow-light effect.",1304.0843v1
2013-08-10,Parametric patterns in optical fiber ring nonlinear resonators,"We propose that parametrically excited patterns, also known as Faraday
patterns, can be observed in nonlinear fiber resonators, where the coefficient
of Kerr nonlinearity is periodically varying along the fiber in resonator. We
study the parametric instability analytically on the basis of the Floquet
theory, also numerically, by direct integration of the system. Instead of
classical Faraday wave excitation scenario, where modulation in time causes
formation of patterns in space, here we propose an inverted scenario, where the
modulation in space excites the patterns in time.",1308.2279v1
2013-12-17,Similariton-like Pulses in Synchronously Pumped Singly Resonant Optical Parametric Oscillators,"Similariton-like pulses are found to be formed in synchronously pumped singly
resonant optical parametric oscillators (OPO) by numerical simulation. The
nonlinear coupled-wave equations can be reduced to inhomogeneous nonlinear
Schr\""{o}dinger equation. The signal pulses with parabola-like temporal
intensity profile and linear chirp are presented in OPO. The similariton-like
pulses in OPO have many practical and potential applications.",1312.4651v2
2014-01-24,Restriction Bounds for the Free Resolvent and Resonances in Lossy Scattering,"We establish high energy $L^2$ estimates for the restriction of the free
Green's function to hypersurfaces in $\mathbb{R}^d$. As an application, we
estimate the size of a logarithmic resonance free region for scattering by
potentials of the form $V\otimes \delta_{\Gamma}$, where $\Gamma \subset
\mathbb{R}^d$ is a finite union of compact subsets of embedded hypersurfaces.
In odd dimensions we prove a resonance expansion for solutions to the wave
equation with such a potential.",1401.6243v1
2014-03-20,Waveguide Model for Thick Complementary Split Ring Resonators,"This paper presents a very simple analytical model for the design of
Frequency Selective Surfaces based on Complementary Split Ring Resonators
(CSRR) within the microwave range. Simple expressions are provided for the most
important geometrical parameters of the model, yielding an accurate description
of the CSRR resonance frequency and avoiding full-wave numerical simulations.
Besides, a qualitative description of the band-pass filter behavior of these
structures is described, considering its high quality factor Q.",1403.5139v1
2014-04-13,Invariant sets and connecting orbits for nonlinear evolution equations at resonance,"We study the problem of existence of orbits connecting stationary points for
the nonlinear heat and strongly damped wave equations being at resonance at
infinity. The main difficulty lies in the fact that the problems may have no
solutions for general nonlinearity. To address this question we introduce
geometrical assumptions for the nonlinear term and use them to prove index
formulas expressing the Conley index of associated semiflows. We also prove
that the geometrical assumptions are generalizations of the well known
Landesman- Lazer and strong resonance conditions. Obtained index formulas are
used to derive criteria determining the existence of orbits connecting
stationary points.",1404.3428v2
2014-07-16,Selective engineering of cavity resonance for frequency matching in optical parametric processes,"We propose to selectively engineer a single cavity resonance to achieve
frequency matching for optical parametric processes in high-Q microresonators.
For this purpose, we demonstrate an approach, selective mode splitting (SMS),
to precisely shift a targeted cavity resonance, while leaving other cavity
modes intact. We apply SMS to achieve efficient parametric generation via
four-wave mixing in high-Q silicon microresonators. The proposed approach is of
great potential for broad applications in integrated nonlinear photonics.",1407.4488v1
2014-11-17,Nonstationary photonic jet from dielectric microsphere,"A photonic jet commonly denotes the specific spatially localized region in
the near-field forward scattering of a light wave at a dielectric micron-sized
particle. We present the detailed calculations of the transient response of an
airborne silica microsphere illuminated by a femtosecond laser pulse. The
spatial area constituting the photonic jet is theoretically investigated and
the temporal dynamics of jet dimensions as well as of jet peak intensity is
analyzed. The role of morphology-dependent resonances in jet formation is
highlighted. The evolution scenario of a nonstationary photonic jet generally
consists of the non-resonant and resonant temporal phases. In every phase, the
photonic jet can change its spatial form and intensity.",1411.4870v1
2015-04-30,Synthetic gauge fields for light beams in optical resonators,"A method to realize artificial magnetic fields for light waves trapped in
passive optical cavities with anamorphic optical elements is theoretically
proposed. In particular, when a homogeneous magnetic field is realized, a
highly-degenerate Landau level structure for the frequency spectrum of the
transverse resonator modes is obtained, corresponding to a cyclotron motion of
the optical cavity field. This can be probed by transient excitation of the
passive optical resonator.",1504.08162v1
2015-05-06,Multiple quasi-phase matched resonant radiations induced by modulation instability in dispersion oscillating fibers,"The propagation of a continuous wave in the average anomalous dispersion
region of a dispersion oscillating fiber is investigated numerically and
experimentally. We demonstrate that the train of solitons arising from
modulation instability is strongly affected by the periodic variations of the
fiber dispersion. This leads to the emission of multiple resonant radiations
located on both sides of the spectrum. Numerical simulations confirm the
experimental results and the position of the resonant radiations is well
predicted by means of perturbation theory.",1505.01256v1
2015-07-09,Modification by pion exchange of near threshold resonance line shape in open heavy flavor channel,"The effect of the pion exchange on the line shape of near threshold
bottomoniumlike resonances decaying into an $S$ wave pair of $B^{(*)}$ mesons
is considered. It is pointed out that this effect, parametrically enhanced by
the heavy meson mass, can be of a practical significance in determining the
parameters of the bottomoniumlike resonances such as the known $Z_b(10610)$ and
$Z_b(10650)$ states.",1507.02639v1
2015-12-02,Resonant Anderson localization in segmented wires,"We discuss a model of random segmented wire, with linear segments of 2D wires
joined by circular bends. The joining vertices act as scatterers on the
propagating electron waves. The model leads to resonant Anderson localization
when all segments are of similar length. The resonant behavior is present with
one and also with several propagating modes. The probability distributions
evolve from diffusive to localized regimes when increasing the number of
segments in a similar way for long and short localization lengths. As a
function of the energy a finite segmented wire typically evolves from localized
to diffusive to ballistic behavior in each conductance plateau.",1512.00680v1
2016-08-31,Controlling mode competition by tailoring the spatial pump distribution in a laser: A resonance-based approach,"We introduce a simplified version of the steady-state ab initio laser theory
for calculating the effects of mode competition in continuous wave lasers using
the passive cavity resonances. This new theory harnesses widely available
numerical methods that can efficiently calculate the passive cavity resonances,
with negligible additional computational overhead. Using this theory, we
demonstrate that the pump profile of the laser cavity can be optimized both for
highly multi-mode and single-mode emission. An open source implementation of
this method has been made available.",1608.08985v1
2016-10-19,"Localization, quantum resonances and ratchet acceleration in a periodically-kicked $\mathcal{PT}$-symmetric quantum rotator","We consider wave transport phenomena in a $\mathcal{PT}$-symmetric extension
of the periodically-kicked quantum rotator model and reveal that dynamical
localization assists the unbroken $\mathcal{PT}$ phase. In the delocalized
(quantum resonance) regime, $\mathcal{PT}$ symmetry is always in the broken
phase and ratchet acceleration arises as a signature of unidirectional
non-Hermitian transport. An optical implementation of the periodically-kicked
$\mathcal{PT}$-symmetric Hamiltonian, based on transverse beam propagation in a
passive optical resonator with combined phase and loss gratings, is suggested
to visualize acceleration modes in fractional Talbot cavities.",1610.06007v1
2018-03-17,"500MHz resonant photodetector for high-quantum-effciency, low-noise homodyne measurement","We design and demonstrate a resonant-type differential photodetector for
low-noise quantum homodyne measurement at 500MHz optical sideband with 17MHz of
bandwidth. By using a microwave monolithic amplifier and a discrete voltage
buffer circuit, a low-noise voltage amplifier is realized and applied to our
detector. 12dB of signal-to-noise ratio of the shot noise to the electric noise
is obtained with 5mW of continuous-wave local oscillator. We analyze the
frequency response and the noise characteristics of a resonant photodetector,
and the theoretical model agrees with the shot noise measurement.",1803.06462v2
2018-09-03,State resolved investigation of Förster resonant energy transfer in collisions between polar molecules and Rydberg atoms,"We perform a comprehensive investigation of F\""orster resonant energy
transfer in a room-temperature thermal mixture of ammonia molecules and
rubidium Rydberg atoms. Fully state-resolved measurement of the Rydberg-atom
populations is achieved by combining millimeter-wave state transfer with
state-selective field ionization. This allows aspects of the energy transfer
process such as state dependence, ammonia pressure dependence, and dependence
on the energy resonance condition to be investigated in detail. Our results
pave the way for future quantum experiments combining polar molecules and
Rydberg atoms.",1809.00624v1
2017-05-02,Wavelength conversion of data at gigabit rates via nonlinear optics in an integrated micro-ring resonator,"We present the first system penalty measurements for all-optical wavelength
conversion in an integrated ring resonator. We achieve wavelength conversion
over a range of 27.7nm in the C-band at 2.5 Gb/s by exploiting four wave mixing
in a CMOS compatible, high index glass ring resonator at ~22 dBm average pump
power, obtaining < 0.3 dB system penalty.",1705.00778v1
2014-06-03,Frequency combs from crystalline resonators: influence of cavity parameters on comb dynamics,"We experimentally study the factors that influence the span in frequency
combs derived from the crystalline whispering gallery mode resonators. We
observe that cavity dispersion plays an important role in generation of combs
by cascaded four wave mixing process. We observed combs from the resonators
with anomalous dispersion and nearly zero dispersion at the pump wavelength. In
addition, the comb generation efficiency is found to be affected by the
crossing of modes of different families. The influence of Raman gain is
discussed as well as the role of cavity diameter and pump power. Copyright 2014
California Institute of Technology. Government sponsorship acknowledged.",1406.0790v1
2018-02-15,Direct Measurement of Coating Thermal Noise in Optical Resonators,"The best measurements of space and time currently possible (e.g.
gravitational wave detectors and optical reference cavities) rely on optical
resonators, and are ultimately limited by thermally induced fluctuations in the
reflective coatings which form the resonator. We present measurements of
coating thermal noise in the audio band and show that for a standard ion beam
sputtered coating, the power spectrum of the noise does not have the expected
power-law behavior.",1802.05372v2
2018-12-30,Nonlinear Coupling of Linearly Uncoupled Resonators,"We demonstrate a system composed of two resonators that are coupled solely
through a nonlinear interaction, and where the linear properties of each
resonator can be controlled locally. We show that this class of dynamical
systems has peculiar properties with important consequences for the study of
classical and quantum nonlinear optical phenomena. As an example we discuss the
case of dual-pump spontaneous four-wave mixing.",1812.11484v1
2016-12-03,Ultralight scalars and resonances in black-hole physics,"Ultralight degrees of freedom coupled to matter lead to resonances, which can
be excited when the Compton wavelength of the field equals a dynamical scale in
the problem. For binaries composed of a star orbiting a supermassive black
hole, these resonances lead to a smoking-gun effect: a periastron distance
which {\it stalls}, even in the presence of gravitational-wave dissipation.
This effect, also called a {\it floating orbit}, occurs for generic equatorial
but eccentric orbits and we argue that finite-size effects are not enough to
suppress it.",1612.00978v2
2008-06-13,Resonant Plasmon-Soliton Interaction,"We describe an effective resonant interaction between two localized wave
modes of different nature: a plasmon-polariton at a metal surface and a
self-focusing beam (spatial soliton) in a non-linear dielectric medium.
Propagating in the same direction, they represent an exotic coupled-waveguide
system, where the resonant interaction is controlled by the soliton amplitude.
This non-linear system manifests hybridized plasmon-soliton eigenmodes, mutual
conversion, and non-adiabatic switching, which offer exciting opportunities for
manipulation of plasmons via spatial solitons.",0806.2183v2
2016-11-29,30-Hz relative linewidth watt output power 1.65-$μ$m continuous-wave singly resonant optical parametric oscillator,"We built a 1-watt cw singly resonant optical parametric oscillator operating
at an idler wavelength of 1.65~$\mu$m for application to quantum interfaces.
The non resonant idler is frequency stabilized by side-fringe locking on a
relatively high-finesse Fabry-Perot cavity, and the influence of intensity
noise is carefully analyzed. A relative linewidth down to the sub-kHz level
(about 30 Hz over 2 s) is achieved. A very good long term stability is obtained
for both frequency and intensity.",1611.09659v3
2019-07-03,Optomechanical tension and crumpling of resonant membranes,"We predict that illumination by a plane electromagnetic wave of optically
resonant membranes, such as graphene or monolayers of transition metal
dichalcogenides, directly affects their mechanical tension. The induced
optomechanical tension is anisotropic and, depending on the spectral detuning
from the resonance, can be both positive and negative. In the latter case, it
can overcome the bending rigidity of the membrane leading to transition to the
crumpled phase. The instability caused by optomechanical heating of flexural
vibrations is also considered.",1907.02010v1
2019-12-31,Series Resonant Matrix Converter Topology for EV DC Fast Charging,"In this paper, we presented a matrix converter with a high-frequency DC link
for EV DC fast charging applications. Introducing this topology allows
eliminating electrolytic capacitors in DC link of the converter, which
potentially increases the reliability and power density of the system. The
converter uses bidirectionally blocking three-phase rectifier to generate a
high-frequency square wave voltage for the series resonant LC DC/DC converter,
eliminating one H-bridge in front of the resonant tank. Principles of
high-frequency and low-frequency modulations are described. A low voltage
prototype has been built and tested which demonstrated ZVS soft switching of
all the transistors in the converter. Peak efficiency estimated as 98.0 % for
state-of-the-art switches.",1912.13241v1
2019-11-04,THz graphene W-shaped three-port circulator with dynamical control,"We propose a new graphene-based THz circulator. It consists of a circular
graphene resonator and three graphene nanoribbon waveguides of W-geometry
placed on a dilectric substrate. Surface plasmon-polariton waves propagate in
the waveguides. The nanoribbon excites in the resonator dipole resonance.
Nonreciprocity of the device is defined by nonsymmetry of the conductivity
tensor of the magnetized graphene. The circulator with the central frequency
7.5 THz has the bandwidth 4.25\% for isolation -15 dB, insertion loss -2.5 dB.
Applied DC magnetic field is 0.56T and Fermi energy of graphene
$\epsilon_F=0.15$eV. The Fermi energy allows one to control dynamically the
circulator responses.",2001.10078v1
2020-07-08,$Λ$ and $Σ$ Excitations and the Quark Model,"The spectrum of $\Lambda$ and $\Sigma$ excitations is reviewed taking into
account (nearly) all hyperon resonances which were seen in early analyses or in
one of the recent partial-wave analyses. The spectrum is compared with the old
Isgur-Karl model and the Bonn model. These models allows us to discuss the
SU(3) structure of the observed resonances. The SU(3) decomposition is compared
with SU(6) relations between the different decay modes. Seven $\Lambda$ states
are proposed to be classified as SU(3) singlet states. The hyperon spectrum is
compared with the spectrum of $N$ and $\Delta$ resonances.",2007.04232v1
2020-10-16,Quasinormal Coupled Mode Theory,"Coupled mode theory (CMT) is a powerful framework for decomposing
interactions between electromagnetic waves and scattering bodies into
resonances and their couplings with power-carrying channels. It has widespread
use in few-resonance, weakly coupled resonator systems across nanophotonics,
but cannot be applied to the complex scatterers of emerging importance. We use
quasinormal modes to develop an exact, ab initio generalized coupled mode
theory from Maxwell's equations. This quasinormal coupled mode theory, which we
denote ""QCMT"", enables a direct, mode-based construction of scattering matrices
without resorting to external solvers or data. We consider canonical scattering
bodies, for which we show that a CMT model will necessarily be highly
inaccurate, whereas QCMT exhibits near-perfect accuracy.",2010.08650v2
2022-02-21,Excitation of absorbing exceptional points in the time domain,"We analyze the time-domain dynamics of resonators supporting exceptional
points (EPs), at which both the eigenfrequencies and the eigenmodes associated
with perfect capture of an input wave coalesce. We find that a time-domain
signature of the EP is an expansion of the class of waveforms which can be
perfectly captured. We show that such resonators have improved performance for
storage or transduction of energy. They also can be used to convert between
waveforms within this class. We analytically derive these features and
demonstrate them for several examples of coupled optical resonator systems.",2202.10567v2
2022-03-09,Evidence of ac-Stark-shifted resonances in intense two-color circularly polarized laser fields,"We report on the appearance of a structure at low energies in the
photo-electron momentum distribution of the hydrogen atom exposed to two-color
counter-rotating bi-circular laser fields. These structures, which arise due to
AC-Stark shifted resonances, break the three-fold symmetry, typical for the
$\omega-2\omega$ bi-circular fields. We discuss the physical origin of this
structure in terms of partial-wave interference between direct ionization
channels and a resonant pathway, that passes through the AC-Stark shifted state
and show how the underlying Rydberg state population depend on the field
strength and pulse duration.",2203.04839v1
2022-10-10,Resonances and Eigenvalues for the Constant Mean Curvature Equation,"In this paper we study resonances and eigenvalues for the nonlinear constant
mean curvature eqn. linearized around the bubbles found by Brezis-Coron. This
nonlinear eqn. is also called a H-system eqn. For degree one bubbles(the degree
relates to a certain winding number) we only find resonances. For higher degree
we prove eigenvalues do occur. Our goal is to eventually obtain dispersive
estimates for the wave eqn. associated to the H-systems eqn. in its linear and
non-linear form, a study of which was initiated by Chanillo-Yung.",2210.04580v1
2024-02-19,Exploring Astrophysically-Relevant Superadiabaticity Driven by Non-Resonant Heating in a Laboratory Magnetized Plasma,"The polytropic index of electrons in a magnetized plasma is experimentally
investigated in the presence of external heating and anisotropic work done on
the system by the magnetic field. The measurements clearly demonstrate
localized regions of superadiabatic electrons due to particle acceleration and
energization through non-resonant betatron and Fermi heating processes. In
regions where wave-induced heating through electron cyclotron resonance
dominates, the plasma electrons behave adiabatically. The realization of
superadiabaticity is universal where heating dominates the work done and has
broader implications for energy exchange processes in astrophysically-relevant
plasmas.",2402.11937v1
2001-03-20,Antiferromagnetically coupled alternating spin chains,"The effect of antiferromagnetic interchain coupling in alternating spin
(1,1/2) chains is studied by mean of a spin wave theory and density matrix
renormalization group (DMRG). In particular, two limiting cases are
investigated, the two-leg ladder and its two dimensional (2D) generalization.
Results of the ground state properties like energy, spin gap, magnetizations,
and correlation functions are reported for the whole range of the interchain
coupling $J_{\perp}$. For the 2D case the spin wave results predict a smooth
dimensional crossover from 1D to 2D keeping the ground state always ordered.
For the ladder system, the DMRG results show that any $J_{\perp}>0$ drives the
system to a gapped ground state. Furthermore the behaviour of the correlation
functions closely resemble the uniform spin-1/2 ladder. For $J_{\perp}$ lower
than 0.3, however, the gap behaves quadratically as $\Delta\sim0.6
J^2_{\perp}$. Finally, it is argued that the behaviour of the spin gap for an
arbitrary number of mixed coupled spin chains is analogous to that of the
uniform spin-1/2 chains.",0103424v1
2001-09-10,Dimensional crossover in alternating spin chains,"The effect of antiferromagnetic interchain coupling in alternating spin
(1,1/2) chains is studied by mean of spin wave theory and density matrix
renormalization group(DMRG). Two limiting cases are investigated, the two-leg
ladder and its two dimensional (2D) generalization. For the 2D case, spin wave
approximation predicts a smooth dimensional crossover keeping the ground state
ordered, whereas in the ladder case the DMRG results show a gapped ground state
for any $J_{\perp}>0$. Furthermore, the behavior of the correlation functions
closely resemble the uniform spin-1/2 ladder. However, for small $J_{\perp}$,
the gap behaves quadratically as $\Delta\sim0.6 J^2_{\perp}$. Similarly to
uniform spin chains, it is conjectured an analogous spin gap behavior for an
arbitrary number of mixed spin chains",0109179v1
2003-10-27,Transverse spin dynamics in a spin-polarized Fermi liquid,"The linear equations for transverse spin dynamics in weakly polarised
degenerate Fermi liquid with arbitrary relationship between temperature and
polarization are derived from Landau-Silin phenomenological kinetic equation
with general form of two-particle collision integral. The temperature and
polarization dependence of the spin current relaxation time is established. It
is found in particular that at finite polarization transverse spin wave damping
has a finite value at T=0. The analogy between temperature dependences of spin
waves attenuation and ultrasound absorption in degenerate Fermi liquid at
arbitrary temperature is presented. We also discuss spin-polarized Fermi liquid
in the general context of the Fermi-liquid theory and compare it with ""Fermi
liquid"" with spontaneous magnetization.",0310620v2
2004-02-16,Magnetic excitations in a bond-centered stripe phase: Spin waves far from the semi-classical limit,"Using a spin-only model, we compute spin excitation spectra in a
bond-centered stripe state with long-range magnetic order. We employ a bond
operator formalism, which naturally captures both dimerization and broken spin
symmetry in a unified framework. At low energies, the spin excitations resemble
spin waves, but at higher energies they are very similar to spin-1 excitations
of isolated spin ladders. Our theory does well describe neutron scattering data
[J. M. Tranquada et al., Nature 429, 534 (2004)] on LaBaCuO, pointing towards
bond order in this material.",0402377v2
2004-06-25,Excitations of incoherent spin-waves due to spin-transfer torque,"As predicted by Slonczewski and Berger, the possibility of exciting microwave
oscillations in a nanomagnet by a spin-polarized current has been recently
demonstrated. This observation opens very important perspectives of
applications in RF components. However, some unresolved inconsistencies are
found when interpreting the magnetization dynamics results within the coherent
spin-torque model (CSM). In some cases, the telegraph noise caused by
spin-currents could not be described quantitatively by the CSM. This led to
controversies about the need of an effective magnetic temperature model (ETM).
Here we interpret the experimental results of Kiselev et al. [Nature 425, 380
(2003)] using micromagnetic simulations. We point out the key role played by
incoherent spin-waves excitation due to spin-transfer effects. The incoherence
is caused by the spatial inhomogeneities of the local fields, generating a
distribution of local precession frequencies. It results in telegraph noise at
zero temperature associated with transitions between attraction wells in phase
space.",0406628v3
2005-05-24,Valence-bond-solid order in antiferromagnets with spin-lattice coupling,"We propose that a valence-bond-solid (VBS) order can be stabilized in certain
two-dimensional antiferromagnets due to spin-lattice coupling. In contrast to
the VBS state of the Affleck-Kennedy-Lieb-Tesaki (AKLT) type in which the spin
$2S$ and the lattice coordination $z$ must be commensurate, the spin-lattice
coupling-induced VBS state can occur when $2S$ is not an integer multiple of
$z$. As a concrete example, S=2 spins on the triangular network with $z=6$ is
discussed. Within the Schwinger boson mean-field theory it is shown that the
ground state is given by the $\sqrt{3}\times\sqrt{3}$ modulation of the valence
bond amplitudes for sufficiently strong spin-lattice coupling. Using the
corresponding AKLT wave function, we work out the excitation spectrum for this
state within the single-mode approximation. The calculated spectrum should
provide a new type of collective mode which is distinct from the spin wave
excitations of the magnetically ordered ground state.",0505573v5
1995-07-13,Monte Carlo Study of the Yukawa Coupled Two Spin Ising Model,"We consider a particular 4 state spin system composed of two Ising spins
(~$s_x, \; \sigma_x$~) with independent hopping parameters $\kappa_1,
\kappa_2$, coupled by a bilinear Yukawa term, $y s_x \sigma_x$. The Yukawa term
is solely responsible for breaking the global $ Z_2 \times Z_2$ symmetry down
to $Z_2$. This model is intended as an illustration of general coupled Higgs
system where scalars can arise both as composite and elementary excitations.
For the Ising example in 2d, we give convincing numerical evidence of the
universality of the two spin system with the one spin Ising model, by Monte
Carlo simulations and finite scaling analysis . We also show that as we
approach the phase transition, universality arises by a separation of low mass
spin waves from an extra set of spin waves with an energy gap that diverges as
the correlations length diverges",9507015v1
2007-08-27,Spin dynamics in a one-dimensional ferromagnetic Bose gas,"We investigate the propagation of spin excitations in a one-dimensional (1D)
ferromagnetic Bose gas. While the spectrum of longitudinal spin waves in this
system is sound-like, the dispersion of transverse spin excitations is
quadratic making a direct application of the Luttinger Liquid (LL) theory
impossible. By using a combination of different analytic methods we derive the
large time asymptotic behavior of the spin-spin dynamical correlation function
for strong interparticle repulsion. The result has an unusual structure
associated with a crossover from the regime of trapped spin wave to an open
regime and does not have analogues in known low-energy universality classes of
quantum 1D systems.",0708.3638v2
2007-11-27,Non-linear dynamics and two-dimensional solitons for spin $ S=1$ ferromagnets with biquadratic exchange,"We develop a consistent semiclassical theory of spin dynamics for an
isotropic ferromagnet with a spin $ S=1$ taking into consideration both
bilinear and biquadratic over spin operators exchange interaction. For such
non-Heisenberg magnets, a peculiar class of spin oscillations and waves, for
which the quantum spin expectation value $ {\rm {\bf m}}=<{\rm {\bf S}}>$ does
not change it direction, but changes in length, is presented. Such
``longitudinal'' excitations do not exist in regular magnets, dynamics of which
are described in terms of the Landau-Lifshitz equation or by means of the spin
Heisenberg Hamiltonian. We demonstrate the presence of non-linear uniform
oscillations and waves, as well as self-localized dynamical excitations
(solitons) with finite energy. A possibility of excitation of such oscillations
by ultrafast laser pulse is discussed.",0711.4285v1
2008-01-28,Modulated spin waves and robust quasi-solitons in classical Heisenberg rings,"We investigate the dynamical behavior of finite rings of classical spin
vectors interacting via nearest-neighbor isotropic exchange in an external
magnetic field. Our approach is to utilize the solutions of a continuum version
of the discrete spin equations of motion (EOM) which we derive by assuming
continuous modulations of spin wave solutions of the EOM for discrete spins.
This continuous EOM reduces to the Landau-Lifshitz equation in a particular
limiting regime. The usefulness of the continuum EOM is demonstrated by the
fact that the time-evolved numerical solutions of the discrete spin EOM closely
track the corresponding time-evolved solutions of the continuum equation. Of
special interest, our continuum EOM possesses soliton solutions, and we find
that these characteristics are also exhibited by the corresponding solutions of
the discrete EOM. The robustness of solitons is demonstrated by considering
cases where initial states are truncated versions of soliton states and by
numerical simulations of the discrete EOM equations when the spins are coupled
to a heat bath at finite temperatures.",0801.4262v1
2008-04-04,"Spin-charge coupling in a band ferromagnet: magnon-energy reduction, anomalous softening, and damping","The effects of correlation-induced coupling between spin and charge
fluctuations on spin-wave excitations in a band ferromagnet are investigated by
including self-energy and vertex corrections within a systematic
inverse-degeneracy expansion scheme which explicitly preserves the Goldstone
mode. Arising from the scattering of a magnon into intermediate spin-excitation
states (including both magnon and Stoner excitations) accompanied with charge
fluctuations in the majority spin band, this spin-charge coupling results not
only in a substantial reduction of magnon energies but also in anomalous
softening and significant magnon damping for zone-boundary modes lying within
the Stoner gap. Our results are in good qualitative agreement with recent
spin-wave excitation measurements in colossal magneto-resistive manganites and
ferromagnetic ultrathin films of transition metals.",0804.0680v1
2008-07-10,Spin rotations induced by electron running on closed trajectories in gated semiconductor nanodevices,"A design for a quantum gate performing transformations of a single electron
spin is presented. The spin rotations are performed by the electron going
around the closed loops in a gated semiconductor device. We demonstrate the
operation of NOT, phase-flip and Hadamard quantum gates, i.e. the single-qubit
gates which are most commonly used in the algorithms. The proposed devices
employ the self-focusing effect for the electron wave packet interacting with
the electron gas on the electrodes and the Rashba spin-orbit coupling. Due to
the self-focusing effect the electron moves in a compact wave packet. The
spin-orbit coupling translates the spatial motion of the electron into the
rotations of the spin. The device does not require microwave radiation and
operates using low constant voltages. It is therefore suitable for selective
single-spin rotations in larger registers.",0807.1627v2
2009-01-15,Spin Rotation Technique for Non-Collinear Magnetic Systems: Application to the Generalized Villain Model,"This work develops a new generalized technique for determining the static and
dynamic properties of any non-collinear magnetic system. By rotating the spin
operators into the local spin reference frame, we evaluate the zeroth, first,
and second order terms in a Holstein-Primakoff expansion, and through a Green's
functions approach, we determine the structure factor intensities for the
spin-wave frequencies. To demonstrate this technique, we examine the spin-wave
dynamics of the generalized Villain model with a varying interchain
interaction. The new interchain coupling expands the overall phase diagram with
the realization of two non-equivalent canted spin configurations. The
rotational Holstein-Primakoff expansion provides both analytical and numerical
results for the spin dynamics and intensities of these phases.",0901.2332v2
2009-08-18,Dynamic spin susceptibility in the t-J model,"A relaxation-function theory for the dynamic spin susceptibility in the
$t$--$J$ model is presented. By a sum-rule-conserving generalized mean-field
approximation (GMFA), the two-spin correlation functions of arbitrary range,
the staggered magnetization, the uniform static susceptibility, and the
antiferromagnetic correlation length are calculated in a wide region of hole
doping and temperaturs. A good agreement with available exact diagonalization
(ED) data is found. The correlation length is in reasonable agreement with
neutron-scattering experiments on La_{2-\delta}Sr_\delta)CuO_4. Going beyond
the GMFA, the self-energy is calculated in the mode-coupling approximation. The
spin dynamics at arbitrary frequencies and wave vectors is studied for various
temperatures and hole doping. At low doping a spin-wave-type behavior is found
as in the Heisenberg model, while at higher doping a strong damping caused by
hole hopping occurs, and a relaxation-type spin dynamics is observed in
agreement with the ED results. The local spin susceptibility and its (\omega/T)
scaling behavior are calculated in a reasonable agreement with experimental and
ED data.",0908.2557v2
2011-08-18,"Bands, spin fluctuations and traces of Fermi surfaces in angle-resolved photoemission intensities for high-$T_C$ cuprates","The band structures of pure and hole doped La$_2$CuO$_4$ with
antiferromagnetic (AFM) spin-fluctuations are calculated and compared to
spectral weights of ARPES. It is shown that observations of coexisting Fermi
surface (FS) arcs and closed FS pockets are consistent with modulated AFM spin
fluctuations of varying wave lengths. Large variations of strong spin
fluctuations make the outer part of the FS break diffuse at low doping. This
part of the FS is suppressed at high doping when spin fluctuations are weak.
The resulting superimposed spectral weight has features both from FS arcs and
closed pockets. A connection between results of ARPES, neutron scattering, and
band results for the modulated AFM spin wave state, suggests that spin-phonon
coupling is an important mechanism for the %pseudogap and other properties of
the cuprates.",1108.3775v1
2012-10-03,Waves of spin-current in magnetized dielectrics,"Spin-current is an important physical quantity in present day spintronics and
it might be very usefull in the physics of quantum plasma of spinning
particles. Thus it is important to have an equation of the spin-current
evolution. This equation naturally appears as a part of a set of the quantum
hydrodynamics (QHD) equations. Consequently, we present the set of the QHD
equations derived from the many-particle microscopic Schrodinger equation,
which consists of the continuity equation, the Euler equation, the Bloch
equation and equation of the spin-current evolution. We use these equations to
study dispersion of the collective excitations in the three dimensional samples
of the magnetized dielectrics. We show that dynamics of the spin-current leads
to formation of new type of the collective excitations in the magnetized
dielectrics, which we called spin-current waves.",1210.1090v2
2013-03-24,Spin-Transfer Torques in Helimagnets,"We theoretically investigate current-induced magnetization dynamics in
chiral-lattice helimagnets. Spin-orbit coupling in non-centrosymmetric crystals
induces a reactive spin-transfer torque that has not been previously
considered. We demonstrate how the torque is governed by the crystal symmetry
and acts as an effective magnetic field along the current direction in cubic
B20-type crystals. The effects of the new torque are computed for
current-induced dynamics of spin-spirals and the Doppler shift of spin waves.
In current-induced spin-spiral motion, the new torque tilts the spiral
structure. The spin waves of the spiral structure are initially displaced by
the new torque, while the dispersion relation is unaffected.",1303.5921v2
2014-03-27,Itinerant magnetism in Weyl spin-orbit coupled Fermi gas,"Magnetic ordering of itinerant fermionic systems is at the forefront of
condensed matter physics dating back to Stoner's instability. Spin-orbit
coupling (SOC) which couples two essential ingredients of an itinerant
fermionic system, namely spin and orbital motion, opens up new horizons to this
long-standing problem. Here we report that the itinerant ferromagnetism is
absent in 3D Fermi gas with a Weyl SOC and various itinerant spin density waves
emerge instead, which is deeply rooted in the unique symmetry and spin-momentum
locking effect in spin-orbit coupled systems. What is more appealing is that,
the strong SOC provides a new and efficient mechanism to realize itinerant spin
density waves at extremely weak repulsion---a significant benefit for present
ultra-cold atom experiment. These novel phenomena can be probed by Bragg
spectroscopy, time of flight imaging and {\sl In-Situ } measurements in
ultra-cold atom experiment.",1403.7031v6
2014-07-03,Design local spin models for Gutzwiller-projected parton wave functions,"We introduce a method to design a local spin Hamiltonian to realize a
Gutzwiller-projected parton wave functions (GPWF) as its ground state. For
example, the Dirac spin liquid (DSL) state is quite close to the true ground
state of the spin-1/2 Heisenberg model on kagome lattice. We examine what kind
of perturbations we should add in order to drive the DSL to more stable chiral
spin liquid (CSL), valence bond solid (VBS) or Gutzwiller-projected spin Hall
(GSH) states. We compute the two-body reduced-density-matrices (2-RDM) of GPWFs
for those target states, and compare them to the 2-RDM of the DSL. This allows
us to design local spin models with only two-body interactions that may realize
those interesting target states. Our results agree very well with recent
numerical calculations for CSL on kagome lattice. We also study spin-1 systems
on kagome lattice, and design local spin models that may realize CSL, VBS and
symmetry-protected topological (SPT) states. Our work establishes a directional
guide for further numerical simulations.",1407.0869v1
2014-10-23,Gravitational waves from spinning compact binaries in hyperbolic orbits,"Compact binaries in hyperbolic orbits are plausible gravitational wave (GW)
sources for the upcoming and planned GW observatories. We develop an efficient
prescription to compute post-Newtonian (PN) accurate ready-to-use GW
polarization states for spinning compact binaries, influenced by the dominant
order spin-orbit interactions, in hyperbolic orbits. This is achieved by
invoking the 1.5PN accurate quasi-Keplerian parameterization for the radial
sector of the orbital dynamics. We probe the influences of spins and
gravitational radiation reaction on $h_+$ and $h_{\times}$ during the
hyperbolic passage. It turns out that both polarization states exhibit the
memory effect for GWs from spinning compact binaries in hyperbolic orbits. In
contrast, only cross polarization state exhibits the memory effect for GWs from
non-spinning compact binaries. Additionally, we compute 1PN accurate amplitude
corrected GW polarization states for hyperbolic non-spinning compact binaries
in a fully parametric manner and perform initial comparisons with the existing
waveforms.",1410.6311v3
2015-01-28,Spin Current in Junctions composed of Multi-band Superconductors with a Spin-density Wave,"We calculate a nondissipative spin current and show that it can flow with or
without a charge current. We consider a two-band model which can be applied to
the description of Fe-based pnictides in coexistence regime of
superconductivity and spin-density wave. Using quasiclassical Green's functions
approach and tunneling Hamiltonian method we show that there exists a
possibility to switch off the Josephson current while leaving the spin current
finite. Moreover, it is possible to have the critical Josephson current and the
critical spin current being proportional to each other, thus giving a
possibility to measure the spin current via the Josephson current. The
underlying mechanism is the interfering hopping of electron--hole pairs between
different bands of the superconductors composing the junction. This is an
intrinsic property of the system and provides a unique and natural way to
utilize junctions made solely of pnictides in promising applications in
spintronics devices.",1501.07280v1
2016-02-27,Nonlinear separate spin evolution in degenerate electron-positron-ion plasmas,"The non-linear evolution of spin-electron acoustic, positron-acoustic, and
spin-electron-positron acoustic waves is considered. It is demonstrated that
weakly nonlinear dynamics of each wave leads to the soliton formation.
Altogether, we report on existence of three different solitons. The
spin-electron acoustic soliton known for electron-ion plasmas is described for
electron-positron-ion plasmas for the first time. The existence of the
spin-electron-positron acoustic soliton is reported for the first time. The
positron-acoustic soliton and the spin-electron-positron acoustic soliton arise
as the areas of a positive electric potential. The spin-electron acoustic
soliton behaves as the area of a negative electric potential at the relatively
small positron imbalance $n_{0p}/n_{0e}=0.1$ and as the area of a positive
electric potential at the relatively large positron imbalance
$n_{0p}/n_{0e}=0.5$.",1602.08640v1
2016-04-06,Antiferromagnetic domain wall motion driven by spin-orbit torques,"We theoretically investigate dynamics of antiferromagnetic domain walls
driven by spin-orbit torques in antiferromagnet/heavy metal bilayers. We show
that spin-orbit torques drive antiferromagnetic domain walls much faster than
ferromagnetic domain walls. As the domain wall velocity approaches the maximum
spin-wave group velocity, the domain wall undergoes Lorentz contraction and
emits spin-waves in the terahertz frequency range. The interplay between spin
orbit torques and the relativistic dynamics of antiferromagnetic domain walls
leads to the efficient manipulation of antiferromagnetic spin textures and
paves the way for the generation of high frequency signals in antiferromagnets.",1604.01473v1
2016-04-11,All-Optical Study of Tunable Ultrafast Spin Dynamics in [Co/Pd]-NiFe Systems: The Role of Spin-Twist Structure on Gilbert Damping,"We investigate optically induced ultrafast magnetization dynamics in [Co(0.5
nm)/Pd(1 nm)]x5/NiFe(t) exchange-spring samples with tilted perpendicular
magnetic anisotropy using a time-resolved magneto-optical Kerr effect
magnetometer. The competition between the out-of-plane anisotropy of the hard
layer, the in-plane anisotropy of the soft layer and the applied bias field
reorganizes the spins in the soft layer, which are modified further with the
variation in t. The spin-wave spectrum, the ultrafast demagnetization time, and
the extracted damping coefficient all depend on the spin distribution in the
soft layer, while the latter two also depend on the spin-orbit coupling between
the Co and Pd layers. The spin-wave spectra change from multimode to
single-mode as t increases. At the maximum field reached in this study, H=2.5
kOe, the damping shows a nonmonotonic dependence on t with a minimum at t=7.5
nm. For t<7.5 nm, intrinsic effects dominate, whereas for t>7.5 nm, extrinsic
effects govern the damping mechanisms.",1604.02998v1
2019-03-27,Observing Black Holes Spin,"The spin of a black hole retains the memory of how the black hole grew, and
can be a potent source of energy for powering relativistic jets. To understand
the diagnostic power and astrophysical significance of black hole spin,
however, we must first devise observational methods for measuring spin. Here, I
describe the current state of black hole spin measurements, highlighting the
progress made by X-ray astronomers, as well as the current excitement of
gravitational wave and radio astronomy based techniques. Today's spin
measurements are already constraining models for the growth of supermassive
black holes and giving new insights into the dynamics of stellar core-collapse,
as well as hinting at the physics of relativistic jet production. Future X-ray,
radio, and gravitational wave observatories will transform black hole spin into
a precision tool for astrophysics and test fundamental theories of gravity.",1903.11704v1
2020-11-09,Spin-wave dynamics and symmetry breaking in an artificial spin ice,"Artificial spin ices are periodic arrangements of interacting nanomagnets
successfully used to investigate emergent phenomena in the presence of
geometric frustration. Recently, it has been shown that artificial spin ices
can be used as building blocks for creating functional materials, such as
magnonic crystals, and support a large number of programmable magnetic states.
We investigate the magnetization dynamics in a system exhibiting anisotropic
magnetostatic interactions owing to locally broken structural inversion
symmetry. We find a rich spin-wave spectrum and investigate its evolution in an
external magnetic field. We determine the evolution of individual modes, from
building blocks up to larger arrays, highlighting the role of symmetry breaking
in defining the mode profiles. Moreover, we demonstrate that the mode spectra
exhibit signatures of long-range interactions in the system. These results
contribute to the understanding of magnetization dynamics in spin ices beyond
the kagome and square ice geometries and are relevant for the realization of
reconfigurable magnonic crystals based on spin ices.",2011.04505v2
2017-01-18,Finite Temperature Phases of Two Dimensional Spin-Orbit Coupled Bosons,"We determine the finite temperature phase diagram of two dimensional bosons
with two hyperfine (pseudo-spin) states coupled via Rashba-Dresselhaus
spin-orbit interaction using classical field Monte Carlo calculations. For
anisotropic spin-orbit coupling, we find a transition to a
Berenzinskii-Kosterlitz-Thouless superfluid phase with quasi-long range order.
We show that the spin-order of the quasi-condensate is driven by the anisotropy
of interparticle interaction, favoring either a homogeneous plane wave state or
stripe phase with broken translational symmetry. Both phases show
characteristic behavior in the algebraically decaying spin density correlation
function. For fully isotropic interparticle interaction, our calculations
indicate a fractionalized quasi-condensate where the mean-field degeneracy of
plane wave and stripe phase remains robust against critical fluctuations. In
the case of fully isotropic spin-orbit coupling, the circular degeneracy of the
single particle ground state destroys the algebraic ordered phase in the
thermodynamic limit, but a cross-over remains for finite size systems.",1701.05002v1
2017-03-02,On the nonlinear NMR and magnon BEC in antiferromagnetic materials with coupled electron-nuclear spin precession,"We present a new study of nonlinear NMR and Bose-Einstein Condensation (BEC)
of nuclear spin waves in antiferromagnetic MnCO3 with coupled electron and
nuclear spins. In particular, we show that the observed behaviour of NMR
signals strongly contradicts the conventional description of paramagnetic
ensembles of noninteracting spins based on the phenomenological Bloch
equations. We present a new theoretical description of the coupled
electron-nuclear spin precession, which takes into account an indirect
relaxation of nuclear spins via the electron subsystem. We show that the
magnitude of the nuclear magnetization is conserved for arbitrary large
excitation powers, which is drastically different from the conventional heating
scenario derived from the Bloch equations. This provides strong evidence that
the coherent precession of macroscopic nuclear magnetization observed
experimentally can be identified with BEC of nuclear spin waves with k=0.",1703.00614v2
2019-04-05,First-principles Study of Spin-wave Excitations of 3$d$ Transition Metals with Linear Combination of Pseudo-atomic Orbitals,"We have employed the generalized Bloch theorem to evaluate the spin stiffness
constants of 3$d$ transition metals (bcc-Fe, fcc-Co, and fcc-Ni) within the
linear combination of pseudo-atomic orbitals (LCPAO). The spin stiffness
constants were obtained by fitting the spin-wave energy curve, which relates to
the total energy difference and the spiral vectors. In order to convince the
reliable spin stiffness constants, we also provided the convergences of spin
stiffness constants in terms of the cutoff radius and the number of orbitals.
After observing the specific cutoff radius and the basis orbital, at which the
spin stiffness constant converges, we used those two parameters to compute the
Curie temperature by using the mean field approximation and the random phase
approximation. For the latter approximation, we applied the so-called Debye
approximation, which is intended to reduce very significantly many required
wavevectors to evaluate the Curie temperature. We claimed that our results are
in good agreement with both other calculations and experiments.",1904.02982v1
2020-06-30,Multi-solitons of the half-wave maps equation and Calogero-Moser spin-pole dynamics,"We consider the half-wave maps (HWM) equation which provides a continuum
description of the classical Haldane-Shastry spin chain on the real line. We
present exact multi-soliton solutions of this equation. Our solutions describe
solitary spin excitations that can move with different velocities and interact
in a non-trivial way. We make an ansatz for the solution allowing for an
arbitrary number of solitons, each described by a pole in the complex plane and
a complex spin variable, and we show that the HWM equation is satisfied if
these poles and spins evolve according to the dynamics of an exactly solvable
spin Calogero-Moser (CM) system with certain constraints on initial conditions.
We also find first order equations providing a B\""acklund transformation of
this spin CM system, generalize our results to the periodic HWM equation, and
provide plots that visualize our soliton solutions.",2006.16826v1
2020-10-13,Effects of spin-orbit torque on the ferromagnetic and exchange spin wave modes in ferrimagnetic CoGd alloy,"We use micro-focus Brillouin light scattering spectroscopy to study the
effects of spin-orbit torque on thermal spin waves in almost angular-momentum
compensated ferrimagnetic CoGd alloy films. The spin-orbit torque is produced
by the electric current flowing in the Pt layer adjacent to CoGd. Both the
ferromagnetic and the exchange modes are detected in our measurements. The
intensity and the linewidth of the ferromagnetic mode are modified by the
spin-orbit torque. In contrast, the properties of the exchange mode are
unaffected by the spin-orbit torque. We also find that the frequencies and the
linewidths of both modes are significantly modified by Joule heating, due to
the strong temperature dependence of the magnetic properties of CoGd in the
vicinity of angular momentum compensation point. Our results provide insight
into the mechanisms that can enable the implementation of sub-THz magnetic
nano-oscillators based on ferrimagnetic materials, as well as related effects
in antiferromagnets.",2010.06615v1
2020-10-22,Spin-current version of solar cells in non-centrosymmetric magnetic insulators,"Photovoltaic effect, e.g., solar cells, converts light into DC electric
current. This phenomenon takes place in various setups such as in
noncentrosymmetric crystals and semiconductor pn junctions. Recently, we
proposed a theory for producing DC spin current in magnets using
electromagnetic waves, i.e., the spin-current counterpart of the solar cells.
Our calculation shows that the nonlinear conductivity for the spin current is
nonzero in a variety of noncentrosymmetric magnets, implying that the
phenomenon is ubiquitous in inversion-asymmetric materials with magnetic
excitations. Intuitively, this phenomenon is a bulk photovoltaic effect of
magnetic excitations, where electrons and holes, visible light, and
inversion-asymmetric semiconductors are replaced with magnons or spinons, THz
or GHz waves, and asymmetric magnetic insulators, respectively. We also show
that the photon-driven spin current is shift current type, and as a result, the
current is stable against impurity scattering. This bulk photovoltaic spin
current is in sharp contrast to that of well-known spin pumping that takes
place at the interface between a magnet and a metal.",2010.11795v1
2021-07-27,Spin transport-induced damping of coherent THz spin dynamics in iron,"We study the damping of perpendicular standing spin-waves (PSSWs) in
ultrathin Fe films at frequencies up to 2.4 THz. The PSSWs are excited by
optically generated ultrashort spin current pulses, and probed optically in the
time domain. Analyzing the wavenumber and thickness dependence of the damping,
we demonstrate that at sufficiently large wave vectors $k$ the damping is
dominated by spin transport effects scaling with k^4 and limiting the frequency
range of observable PSSWs. Although this contribution is known to originate in
the spin diffusion, we argue that at moderate and large k a more general
description is necessary and develop a model where the 'transverse spin mean
free path' is the a key parameter, and estimate it to be ~0.5 nm.",2107.12812v2
2021-09-14,Magnon Condensation in Dimerized Antiferromagnets with Spin-Orbit Coupling,"Bose-Einstein condensation (BEC) of triplet excitations triggered by a
magnetic field, sometimes called magnon BEC, in dimerized antiferromagnets
gives rise to a long-range antiferromagnetic order in the plane perpendicular
to the applied magnetic field. To explore the effects of spin-orbit coupling on
magnon condensation, we study a spin model on a distorted honeycomb lattice
with dimerized Heisenberg exchange ($J$ terms) and uniform off-diagonal
exchange ($\Gamma'$ terms) interactions. Via variational Monte Carlo
calculations and spin-wave theory, we find that an out-of-plane magnetic field
can induce different types of long-range magnetic orders, no matter if the
ground state is a non-magnetic dimerized state or an ordered N\'{e}el state.
Furthermore, the critical properties of field-driven phase transitions in the
presence of spin-orbit couplings, as illustrated from spin-wave spectrum and
interpreted by effective field theory, can be different from the conventional
magnon BEC. Our study is helpful to understand the rich phases of spin-orbit
coupled antiferromagnets induced by magnetic fields.",2109.06518v2
2021-11-15,Phase diagram and post-quench dynamics in a double spin-chain system in transverse fields,"We propose and explore the physics of a toy multiferroic model by coupling
two distinct dipolar XXZ models in transverse fields. We determine first the
rich ground-state phase diagram of the model using density matrix
renormalization group techniques. Then, we explore the dynamics of the system
after global and local quenches, using the time-evolving block decimation
algorithm. After a global quench, the system displays decaying coupled
oscillations of the electric and magnetic spins, in agreement with the
Eigenstate Thermalization Hypothesis (ETH) for many-body interacting quantum
systems. Notably, the spin-spin interactions lead to a sizeable quadratic shift
in the oscillation frequency as the inter-chain coupling is increased. Local
quenches lead to a light-cone-like propagation of excitations. In this case,
the inter-chain coupling drives a transfer of energy between the chains that
generates a novel fast spin-wave mode along the 'magnetic' chain at the speed
of the 'electric' spin-wave. This suggests a limited control mechanism for
faster information transfer in magnetic spin chains using electric fields that
harnesses the electric dipoles as intermediaries.",2111.07831v1
2022-05-31,Propagation of spin channel waves,"A mutilated model is constructed to approximate the collision term of spin
Boltzmann equation that incorporates newly appearing collisional invariants
i.e, the total angular momentum. With recourse to degenerate perturbation
theory, the dispersion relations of hydrodynamic modes are formulated, among
which spin modes are responsible for spin equilibration. We find that the
non-locality does not change the sound speed but slows down the propagation of
spin channel waves. The damping rates of spin modes are close to those of
spinless modes over a reasonable parameter value range. The results reveal that
both spin and momentum should be treated simultaneously in a unified transport
framework. In the nonrelativistic limit, the short-wavelength behavior for
normal modes is also explored and there exists a critical point for every
distinct discrete mode over which only quasiparticle modes contribute.",2205.15755v2
2022-07-19,"Magnetic interactions in AB-stacked kagome lattices: magnetic structure, symmetry, and duality","We present the results of an extensive study of the phase diagram and spin
wave excitations for a general spin model on a hexagonal AB-stacked kagome
system. The boundaries of the magnetic phases are determined via a combination
of numerical (Monte Carlo) and analytical (Luttinger-Tisza) methods. We also
determine the phase coexistence regions by considering the instabilities in the
spin wave spectra. Depending on the strength of the spin-orbit coupling (SOC),
some spin and lattice rotations become decoupled, leading to considerably
larger symmetry groups than typical magnetic groups. Thus, we provide a
detailed symmetry description of the magnetic Hamiltonian with negligible,
weak, and intermediate strength of SOC. The spin symmetry in these three cases
has a strong effect on the splittings observed in the spin excitation spectra.
We further identify a number of self-duality transformations that map the
Hamiltonian onto itself. These transformations describe the symmetry of the
parameter space and provide an exact mapping between the properties of
different magnetic orders and lead to accidental degeneracies. Finally, we
discuss the physical relevance of our findings in the context of
$\mathrm{Mn}_3X$ compounds.",2207.09297v1
2022-09-01,Spin contributions to the gravitational-waveform modes for spin-aligned binaries at the 3.5PN order,"We complete the post-Newtonian (PN) prediction at the 3.5PN order for the
spin contributions to the gravitational waveforms emitted by inspiraling
compact binaries, in the case of quasi-circular, equatorial orbits, where both
spins are aligned with the orbital angular momentum. Using results from the
multipolar post-Minkowskian wave generation formalism, we extend previous works
that derived the dynamics and gravitational-wave energy flux and phasing, by
computing the full waveform decomposed in spin-weighted spherical harmonics.
This new calculation requires the computation of multipolar moments of higher
multipolar order, new quadratic-in-spin contributions to the hereditary tail
terms entering at the 3.5PN order, as well as other non-linear interactions
between moments. When specialized to the test-mass limit, our results are
equivalent to those obtained in the literature for the waveform emitted by a
test-mass in equatorial, circular orbits around a Kerr black hole. We also
compute the factorized modes for use in effective-one-body waveform models,
correcting the 2.5PN nonspinning and 3PN quadratic-in-spin terms in the (2,1)
mode used in current models.",2209.00374v2
2022-12-02,Coherent magnon-induced domain wall motion in a magnetic insulator channel,"Advancing the development of spin-wave devices requires high-quality
low-damping magnetic materials where magnon spin currents can propagate
efficiently and interact effectively with local magnetic textures. We show that
magnetic domain walls (DW) can modulate spin-wave transport in perpendicularly
magnetized channels of Bi-doped yttrium-iron-garnet (BiYIG). Conversely, we
demonstrate that the magnon spin current can drive DW motion in the BiYIG
channel device by means of magnon spin-transfer torque. The DW can be reliably
moved over 15 um distances at zero applied magnetic field by a magnon spin
current excited by an RF pulse as short as 1 ns. The required energy for
driving DW motion is orders of magnitude smaller than those reported for
metallic systems. These results facilitate low-switching-energy magnonic
devices and circuits where magnetic domains can be efficiently reconfigured by
magnon spin currents flowing within magnetic channels.",2212.01408v1
2023-05-25,Dynamics of the antiferromagnetic spin ice phase in pyrochlore spinels,"Motivated by the classical spin-nematic state observed in the breathing
pyrochlore spinel LiGa$_{0.95}$In$_{0.05}$Cr$_4$O$_8$, we theoretically discuss
spin dynamics in models of spin-lattice coupling in these materials.
Semiclassical dynamical simulations successfully recover the key features of
inelastic neutron-scattering experiments on
LiGa$_{0.95}$In$_{0.05}$Cr$_4$O$_8$: a broad finite-energy peak alongside a
continuum of scattering near the (200) wave vector that extends from the
elastic line to high energies. To interpret this result, we develop a
small-fluctuation theory for the spin-ice-like nematic ground states, analogous
to linear spin-wave theory for conventionally ordered magnets, which reproduces
the numerical simulation results quantitatively. In particular, we find that
the inelastic peak is well explained by collective modes confined to
ferromagnetic loops of the underlying nematic order. In addition, we find a
sharp, linearly dispersing mode in the dynamical structure factor, which
originates in long-wavelength fluctuations of the nematic director: We believe
identifying this mode will be an interesting target for future experiments on
these materials. We also outline potential future applications of our methods
to both pyrochlore spinels and other spin-nematic systems.",2305.16386v1
2024-01-24,Building a bridge between comparable and extreme mass ratio black hole binaries: a single spin precessing model for the final state,"Modelling the gravitational wave signal from binaries beyond comparable mass
is an important open issue in gravitational wave astronomy. For non-spinning
binaries and when the spins are aligned with the orbital angular momentum, some
first studies concerning the transition between the comparable and extreme mass
ratio regime are already available, which suggest that extreme mass ratio
results at times extrapolate to comparable mass ratios with surprising
precision. Here we study the case of misaligned spins: We present new NR
simulations performed with the Einstein Toolkit code at mass ratios up to 18
and construct a heterogeneous dataset that spans all mass ratios, including
data from NR simulations, numerical approximations to extreme mass ratio
binaries, and data from the geodesic approximation. As a first application we
provide fits for the remnant mass and spin magnitude in single spin precessing
systems, omitting consideration of the in-plane spin orientation. These fits
demonstrate accuracy comparable to the state-of-the-art NRSur7dq4EmriRemnant
model, all while retaining the simplicity and efficiency inherent in previous
phenomenological fits.",2401.13342v2
2024-03-20,Emission of fast-propagating spin waves by an antiferromagnetic domain wall driven by spin current,"Antiferromagnets (AFMs) have great benefits for spintronic applications such
as high frequencies (up to THz), high speeds (up to tens of km/s) of magnetic
excitations, and field-free operation. Advanced devices will require high-speed
propagating spin waves (SWs) as signal carriers, i.e., SWs with high k-vectors,
the excitation of which remains challenging. We show that a domain wall (DW) in
anisotropic AFM driven by the spin current can be a source of such propagating
SWs with high frequencies and group velocities. In the proposed generator, the
spin current, with polarization directed along the easy anisotropy axis,
excites the precession of the N\'eel vector within the DW. The threshold
current is defined by the value of the anisotropy in the hard plane, and the
frequency of the DW precession is tuneable by the strength of the spin current.
We show that the above precession of spins inside the DW leads to robust
emission of high-frequency propagating SWs into the AFM strip with very short
wavelengths comparable to the exchange length, which is hard to achieve by any
other method.",2403.13949v1
2007-08-14,Correlated behavior of conductance and phase rigidity in the transition from the weak-coupling to the strong-coupling regime,"We study the transmission through different small systems as a function of
the coupling strength $v$ to the two attached leads. The leads are identical
with only one propagating mode $\xi^E_C$ in each of them. Besides the
conductance $G$, we calculate the phase rigidity $\rho$ of the scattering wave
function $\Psi^E_C$ in the interior of the system. Most interesting results are
obtained in the regime of strongly overlapping resonance states where the
crossover from staying to traveling modes takes place. The crossover is
characterized by collective effects. Here, the conductance is plateau-like
enhanced in some energy regions of finite length while corridors with zero
transmission (total reflection) appear in other energy regions. This
transmission picture depends only weakly on the spectrum of the closed system.
It is caused by the alignment of some resonance states of the system with the
propagating modes $\xi^E_C$ in the leads. The alignment of resonance states
takes place stepwise by resonance trapping, i.e. it is accompanied by the
decoupling of other resonance states from the continuum of propagating modes.
This process is quantitatively described by the phase rigidity $\rho$ of the
scattering wave function. Averaged over energy in the considered energy window,
$<G>$ is correlated with $1-<\rho>$. In the regime of strong coupling, only two
short-lived resonance states survive each aligned with one of the channel wave
functions $\xi^E_C$. They may be identified with traveling modes through the
system. The remaining $M-2$ trapped narrow resonance states are well separated
from one another.",0708.1910v2
2020-04-16,Mathematical analysis of the acoustic imaging modality using bubbles as contrast agents at nearly resonating frequencies,"We analyze mathematically the acoustic imaging modality using bubbles as
contrast agents. These bubbles are modeled by mass densities and bulk moduli
enjoying contrasting scales. These contrasting scales allow them to resonate at
certain incident frequencies. We consider two types of such contrasts. In the
first one, the bubbles are light with small bulk modulus, as compared to the
ones of the background, so that they generate the Minnaert resonance
(corresponding to a local surface wave). In the second one, the bubbles have
moderate mass density but still with small bulk modulus so that they generate a
sequence of resonances (corresponding to local body waves).
  We propose to use as measurements the far-fields collected before and after
injecting a bubble, set at a given location point in the target domain,
generated at a band of incident frequencies and at a fixed single
backscattering direction. Then, we scan the target domain with such bubbles and
collect the corresponding far-fields. The goal is to reconstruct both the,
variable, mass density and bulk modulus of the background in the target region.
  1. We show that, for each fixed used bubble, the contrasted far-fields reach
their maximum value at, incident, frequencies close to the Minneart resonance
(or the body-wave resonances depending on the types of bubbles we use). Hence,
we can reconstruct this resonance from our data. The explicit dependence of the
Minnaert resonance in terms of the background mass density of the background
allows us to recover it, i.e. the mass density, in a straightforward way.
  2. In addition, this measured contrasted far-fields allow us to recover the
total field at the location points of the bubbles (i.e. the total field in the
absence of the bubbles). A numerical differentiation argument, for instance,
allows us to recover the bulk modulus of the targeted region as well.",2004.07808v1
2021-08-20,Resonant Spontaneous Bremsstrahlung Effect In The Scattering Of Ultrarelativistic Electrons On Nuclei In A Strong Laser Field,"The process of resonant spontaneous bremsstrahlung radiation during the
scattering of ultrarelativistic electrons with energies of the order $\sim 100\
\text{GeV}$ by the nuclei in strong laser fields with intensities up to $I\sim
{{10}^{24}}\ \text{Wc}{{\text{m}}^{\text{-2}}}$ is theoretically studied. Under
resonant conditions, an intermediate electron in the wave field enters the mass
shell. As a result, the initial second-order process by the fine structure
constant is effectively reduced to two first-order processes: laser-stimulated
Compton effect and laser-assisted Mott process. The resonant kinematics for two
reaction channels (A and B) is studied in detail. It is shown that in the
resonant case there is a characteristic parameter that determines a significant
number of absorbed laser photons in the laser-stimulated Compton effect. This
parameter is determined by the parameters of the laser installation, the energy
of the initial electrons and is proportional to the intensity of the laser
wave. An analytical resonant differential cross-section with simultaneous
registration of the frequency and the outgoing angle of a spontaneous
gamma-quantum is obtained. It is shown that the resonant differential
cross-section has the largest value in the region of average laser fields
($I\sim {{10}^{18}}\ \text{Wc}{{\text{m}}^{\text{-2}}}$) and can be of the
order of $\sim {{10}^{18}}$ in units ${{Z}^{2}}\alpha r_{e}^{2}$. With an
increase in the intensity of the laser wave, the value of the resonant
differential cross-section decreases and for the intensity $I\sim {{10}^{24}}\
\text{Wc}{{\text{m}}^{\text{-2}}}$ is of the order of $\sim {{10}^{4}}$ in
units ${{Z}^{2}}\alpha r_{e}^{2}$. The obtained results reveal new features of
spontaneous emission of ultrarelativistic electrons on nuclei in strong laser
fields and can be tested at international laser installations.",2108.10186v1
2017-02-10,Spin memory effect for compact binaries in the post-Newtonian approximation,"The spin memory effect is a recently predicted relativistic phenomenon in
asymptotically flat spacetimes that become nonradiative infinitely far in the
past and future. Between these early and late times, the magnetic-parity part
of the time integral of the gravitational-wave strain can undergo a nonzero
change; this difference is the spin memory effect. Families of freely falling
observers around an isolated source can measure this effect, in principle, and
fluxes of angular momentum per unit solid angle (or changes in superspin
charges) generate the effect. The spin memory effect had not been computed
explicitly for astrophysical sources of gravitational waves, such as compact
binaries. In this paper, we compute the spin memory in terms of a set of
radiative multipole moments of the gravitational-wave strain. The result of
this calculation allows us to establish the following results about the spin
memory: (i) We find that the accumulation of the spin memory behaves in a
qualitatively different way from that of the displacement memory effect for
nonspinning, quasicircular compact binaries in the post-Newtonian
approximation: the spin memory undergoes a large secular growth over the
duration of the inspiral, whereas for the displacement effect this increase is
small. (ii) The rate at which the spin memory grows is equivalent to a
nonlinear, but nonoscillatory and nonhereditary effect in the gravitational
waveform that had been previously calculated for nonspinning, quasicircular
compact binaries. (iii) This rate of build-up of the spin memory could
potentially be detected by future gravitational-wave detectors by carefully
combining the measured waveforms from hundreds of gravitational-wave detections
of compact binaries.",1702.03300v3
2017-11-28,Non-radiating angularly accelerating electron waves,"Accelerating electrons are known to radiate electromagnetic waves, a property
that is central to the concept of many devices, from antennas to synchrotrons.
While the electrodynamics of accelerating charged particles is well understood,
the same is not true for charged matter waves: would a locally accelerating
charged matter wave, like its particle counterpart, radiate? Here we construct
a novel class of matter waves, angular accelerating electron waves, by
superpositions of twisted electrons carrying orbital angular momentum. We study
the electrodynamic behaviour of such accelerating matter waves and reveal the
generation of a solenoidal magnetic field in each component, and an
accelerating electron wave that does not radiate. These novel properties will
have practical impact in spin flipping of qubits for quantum information
processing, have been suggested for control of time dilation and length
contraction, and raise fundamental questions as to the nature of wave-particle
duality in the context of radiating charged matter.",1711.10114v1
2018-03-28,Massless surface wave,"An interface between two media is topologically stable two-dimensional object
where 3D-symmetry breaks which allows for existence of many exotic excitations.
A direct way to explore surface excitations is to investigate their interaction
with the surface waves, such as very well known capillary-gravity waves and
crystallization waves. Helium remains liquid down to absolute zero where bulk
excitations are frozen out and do not mask the interaction of the waves with
the surface states. Here we show the possibility of the new, massless wave
which can propagate along the surface between two different superfluids phases
of $^3$He. The displacement of the surface in this wave occurs due to the
transition of helium atoms from one phase to another, so that there is no flow
of particles as densities of phases are equal. We calculate the dispersion of
the wave in which the inertia is provided by spin supercurrents, and the
restoring force is magnetic field gradient. We calculate the dissipation of the
wave and show the preferable conditions to observe it.",1803.10489v1
2019-12-18,Penetration of wind-generated near-inertial waves into a turbulent ocean,"An idealized storm scenario is examined in which a wind-generated inertial
wave interacts with a turbulent baroclinic quasi-geostrophic flow. The flow is
initialized by spinning up a Eady model with a realistic stratification
profile. The storm is modeled as an initial value problem for a mixed-layer
confined, horizontally-uniform inertial oscillation. The primordial inertial
oscillation then evolves under the effects of advection, refraction, dispersion
and dissipation. Waves feedback onto the flow by modifying its potential
vorticity. In the first few days, refraction dominates and wave energy is
attracted (repelled) by regions of negative (positive) vorticity. Wave energy
is subsequently drained down anticyclonic pipes. This drainage halts as wave
energy encounters weakening vorticity. After a week or two, wave energy
accumulates at the bottom of negative vorticity features, i.e. along
filamentary structures at shallow depths and in larger anticyclones at greater
depths. Wave feedback tends to weaken vortices and thus slow down wave
penetration. This effect, however, is found to be weak even for vigorous
storms.",1912.08323v1
2023-05-11,Searches for continuous gravitational waves from neutron stars: A twenty-year retrospective,"Seven years after the first direct detection of gravitational waves, from the
collision of two black holes, the field of gravitational wave astronomy is
firmly established. A first detection of continuous gravitational waves from
rapidly-spinning neutron stars could be the field's next big discovery. I
review the last twenty years of efforts to detect continuous gravitational
waves using the LIGO and Virgo gravitational wave detectors. I summarise the
model of a continuous gravitational wave signal, the challenges to finding such
signals in noisy data, and the data analysis algorithms that have been
developed to address those challenges. I present a quantitative analysis of 297
continuous wave searches from 80 papers, published from 2003 to 2022, and
compare their sensitivities and coverage of the signal model parameter space.",2305.07106v2
2024-04-11,Vortex-carrying solitary gravity waves of large amplitude,"In this paper, we study two-dimensional traveling waves in finite-depth water
that are acted upon solely by gravity. We prove that, for any supercritical
Froude number (non-dimensionalized wave speed), there exists a continuous
one-parameter family $\mathcal{C}$ of solitary waves in equilibrium with a
submerged point vortex. This family bifurcates from an irrotational uniform
flow, and, at least for large Froude numbers, extends up to the development of
a surface singularity. These are the first rigorously constructed gravity
wave-borne point vortices without surface tension, and notably our formulation
allows the free surface to be overhanging. We also provide a numerical
bifurcation study of traveling periodic gravity waves with submerged point
vortices, which strongly suggests that some of these waves indeed overturn.
Finally, we prove that at generic solutions on $\mathcal{C}$ $\unicode{x2013}$
including those that are large amplitude or even overhanging $\unicode{x2013}$
the point vortex can be desingularized to obtain solitary waves with a
submerged hollow vortex. Physically, these can be thought of as traveling waves
carrying spinning bubbles of air.",2404.08074v1
2021-09-21,Wave Function Identity: A New Symmetry for 2-electron Systems in an Electromagnetic Field,"Stationary-state Schr{\""o}dinger-Pauli theory is a description of electrons
with a spin moment in an external electromagnetic field. For 2-electron systems
as described by the Schr{\""o}dinger-Pauli theory Hamiltonian with a symmetrical
binding potential, we report a new symmetry operation of the electronic
coordinates. The symmetry operation is such that it leads to the equality of
the transformed wave function to the wave function. This equality is referred
to as the Wave Function Identity. The symmetry operation is a two-step process:
an interchange of the spatial coordinates of the electrons whilst keeping their
spin moments unchanged, followed by an inversion. The Identity is valid for
arbitrary structure of the binding potential, arbitrary electron interaction of
the form $w(|{\bf{r}} - {\bf{r}}'|)$, all bound electronic states, and
arbitrary dimensionality. It is proved that the exact wave functions satisfy
the Identity. On application of the permutation operation for fermions to the
identity, it is shown that the parity of the singlet states is even and that of
triplet states odd. As a consequence, it follows that at electron-electron
coalescence, the singlet state wave functions satisfy the cusp coalescence
constraint, and triplet state wave functions the node coalescence condition.
Further, we show that the parity of the singlet state wave functions about all
points of electron-electron coalescence is even, and that of the triplet state
wave functions odd. The Wave Function Identity and the properties on parity,
together with the Pauli principle, are then elucidated by application to the
$2$-dimensional $2$-electron `artificial atoms' or semiconductor quantum dots
in a magnetic field in their first excited singlet $2^{1}S$ and triplet $2^{3}
S$ states.",2109.10338v1
2013-08-13,Dirac dynamical resonance states around Schwarzschild black holes,"Recently, a novel kind of scalar wigs around Schwarzschild black
holes---scalar dynamical resonance states were introduced in [Phys. Rev. D 84,
083008 (2011)] and [Phys. Rev. Lett. 109, 081102 (2012)]. In this paper, we
investigate the existence and evolution of Dirac dynamical resonance states.
First we look for stationary resonance states of a Dirac field around a
Schwarzchild black hole by using the Schr\""{o}dinger-like equations reduced
from the Dirac equation in Schwarzschild spacetime. Then Dirac
pseudo-stationary configurations are constructed from the stationary resonance
states. We use these configurations as initial data and investigate their
numerical evolutions and energy decay. These dynamical solutions are the
so-called ""Dirac dynamical resonance states"". It is found that the energy of
the Dirac dynamical resonance states shows an exponential decay. The decay rate
of energy is affected by the resonant frequency, the mass of Dirac field, the
total angular momentum, and the spin-orbit interaction. In particular, for
ultra-light Dirac field, the corresponding particles can stay around a
Schwarzschild black hole for a very long time, even for cosmological
time-scales.",1308.2863v3
2017-07-06,Improving superconducting resonators in magnetic fields by reduced field-focussing and engineered flux screening,"We experimentally investigate superconducting coplanar waveguide resonators
in external magnetic fields and present two strategies to reduce field-induced
dissipation channels and resonance frequency shifts. One of our approaches is
to significantly reduce the superconducting ground-plane areas, which leads to
reduced magnetic field-focussing and thus to lower effective magnetic fields
inside the waveguide cavity. By this measure, the field-induced losses can be
reduced by more than one order of magnitude in mT out-of-plane magnetic fields.
When these resonators are additionally coupled inductively instead of
capacitively to the microwave feedlines, an intrinsic closed superconducting
loop is effectively shielding the heart of the resonator from magnetic fields
by means of flux conservation. In total, we achieve a reduction of the
field-induced resonance frequency shift by up to two orders of magnitude. We
combine systematic parameter variations on the experimental side with numerical
magnetic field calculations to explain the effects of our approaches and to
support our conclusions. The presented results are relevant for all areas,
where high-performance superconducting resonators need to be operated in
magnetic fields, e.g. for quantum hybrid devices with superconducting circuits
or electron spin resonance detectors based on coplanar waveguide cavities.",1707.01936v1
2018-02-14,Magnetic Field Dependent Microwave Losses in Superconducting Niobium Microstrip Resonators,"We describe an experimental protocol to characterize magnetic field dependent
microwave losses in superconducting niobium microstrip resonators. Our approach
provides a unified view that covers two well-known magnetic field dependent
loss mechanisms: quasiparticle generation and vortex motion. We find that
quasiparticle generation is the dominant loss mechanism for parallel magnetic
fields. For perpendicular fields, the dominant loss mechanism is vortex motion
or switches from quasiparticle generation to vortex motion, depending on
cooling procedures. In particular, we introduce a plot of the quality factor
versus the resonance frequency as a general method for identifying the dominant
loss mechanism. We calculate the expected resonance frequency and the quality
factor as a function of the magnetic field by modeling the complex resistivity.
Key parameters characterizing microwave loss are estimated from comparisons of
the observed and expected resonator properties. Based on these key parameters,
we find a niobium resonator whose thickness is similar to its penetration depth
is the best choice for X-band electron spin resonance applications. Finally, we
detect partial release of the Meissner current at the vortex penetration field,
suggesting that the interaction between vortices and the Meissner current near
the edges is essential to understand the magnetic field dependence of the
resonator properties.",1802.05183v3
2021-03-26,Microwave resonances of magnetic skyrmions in thin film multilayers,"Non-collinear magnets exhibit a rich array of dynamic properties at microwave
frequencies. They can host nanometre-scale topological textures known as
skyrmions, whose spin resonances are expected to be highly sensitive to their
local magnetic environment. Here, we report a magnetic resonance study of an
[Ir/Fe/Co/Pt] multilayer hosting N\'eel skyrmions at room temperature.
Experiments reveal two distinct resonances of the skyrmion phase during
in-plane ac excitation, with frequencies between 6-12 GHz. Complementary
micromagnetic simulations indicate that the net magnetic dipole moment rotates
counterclockwise (CCW) during both resonances. The magnon probability
distribution for the lower-frequency resonance is localised within isolated
skyrmions, unlike the higher-frequency mode which principally originates from
areas between skyrmions. However, the properties of both modes depend
sensitively on the out-of-plane dipolar coupling, which is controlled via the
ferromagnetic layer spacing in our heterostructures. The gyrations of stable
isolated skyrmions reported in this room temperature study encourage the
development of new material platforms and applications based on skyrmion
resonances. Moreover, our material architecture enables the resonance spectra
to be tuned, thus extending the functionality of such applications over a
broadband frequency range.",2103.14524v1
2022-04-04,"Quantum dimer model on fullerenes: resonance, scarring and confinement","The earliest known examples of quantum superposition were found in organic
chemistry -- in molecules that `resonate' among multiple arrangements of
$\pi$-bonds. Small molecules such as benzene resonate among a few bond
arrangements. In contrast, a large system that stretches over a macroscopic
lattice may resonate among an extensive number of configurations. This is
analogous to a quantum spin liquid as described by Anderson's resonating
valence bond (RVB) picture. In this article, we study the intermediate case of
somewhat large molecules, the C$_{20}$ and C$_{60}$ fullerenes. We build a
minimal description in terms of quantum dimer models, allowing for local
resonance processes and repulsion between proximate $\pi$-bonds. This allows us
to characterize ground-states, e.g., with C$_{60}$ forming a superposition of
5828 dimer covers. Despite the large number of contributing dimer covers, the
ground state shows strong dimer-dimer correlations. Going beyond the ground
state, the full spectrum of C$_{60}$ shows many interesting features. Its
Hilbert space is bipartite, leading to spectral reflection symmetry. It has a
large number of protected zero-energy states. In addition, the spectrum
contains many scar-like states, corresponding to localized
dimer-rearrangement-dynamics. Resonance dynamics in QDMs can manifest in the
behaviour of defects, potentially binding defects via an effective attractive
interaction. To test this notion, we introduce pairs of vacancies at all
possible separations. Resonance energy reaches its lowest value when the
vacancies are closest to one another. This suggests confinement of monomers,
albeit within a finite cluster. We discuss qualitative pictures for
understanding bonding in fullerenes and draw connections with results from
quantum chemistry.",2204.01756v1
2022-05-02,Regarding the possibility to observe the LHCb hidden-charm strange pentaquark $P_{cs}(4459)^0$ in antikaon-induced $J/ψ$ meson production on protons and nuclei near the $J/ψ$$Λ$ production threshold,"We study the near-threshold $J/\psi$ meson production on protons and nuclei
by considering incoherent direct non-resonant $K^-p \to {J/\psi}\Lambda$ and
two-step resonant ${K^-}p \to P_{cs}(4459)^0 \to {J/\psi}\Lambda$ charmonium
production processes. We calculate the absolute excitation functions, energy
and momentum distributions for the non-resonant, resonant and for the combined
(non-resonant plus resonant) production of $J/\psi$ mesons off protons as well
as off carbon and tungsten target nuclei at near-threshold incident antikaon
energies by considering these elementary production channels as well as by
assuming the spin-parity assignment of the hidden-charm resonance
$P_{cs}(4459)^0$ with strangeness as $J^P=(3/2)^-$ within six different
scenarios for the branching ratio $Br[P_{cs}(4459)^0 \to {J/\psi}\Lambda]$ of
the decay $P_{cs}(4459)^0 \to {J/\psi}\Lambda$. We show that the combined
observables considered reveal definite sensitivity to these scenarios, which
means that they may be an important tool to provide further evidence for the
existence of the pentaquark $P_{cs}(4459)^0$ resonance and to get valuable
information on its decay rate to the ${J/\psi}\Lambda$ final state. Their
measurements could be performed in the future at the J-PARC Hadron Experimental
Facility.",2205.00728v1
2023-05-07,Photocatalytic oxidation in few-layer Tellurene for loss-invariant integrated photonic resonance trimming,"Two-dimensional materials with unique physicochemical properties promote
photocatalytic activities. As the 2D material composites research studies the
statistical average of complex catalytic behaviors, an integrated photonic
platform allows clean and single flake level photo-catalytic investigations
with precisely quantified photocatalytic activities. In this paper, we track
fluence-dependent photo-oxidation in two-dimensional Tellurene (2D Te) by the
evanescently coupled micro-resonator. Nearly 32 perent of oxidation is achieved
in 10 nm 2D Te flake, compared to only 4.5% oxidation in 30 nm sample, probed
by the resonance shift in silicon microring resonators (MRRs) substrate. The
wider bandgap in the few layers of 2D Te allows faster charge transfer to
adsorbed oxygen for a more efficient photocatalytic redox reaction. The
photo-oxidation in hybrid 2D Te results in an invariant lineshapes of optical
transmission resonance for wavelength trimming (more than 3 times resonance
bandwidth). The low threshold power, near-infrared, and in-waveguide resonance
trimming scheme is compatible with most integrated photonic setups for easy
fixing the nanofabrication-induced random resonance deviation for integrated
photonic circuit applications in wavelength-division-multiplexing systems and
spin qubits quantum computing.",2305.04342v1
2006-04-07,On calculation of elementary particles' masses,"The purpose of present paper is to develop the approach to calculation of the
mass spectra of elementary particles within the framework of the resonance
theory of elementary particles as de Broglie waves",0604063v1
2009-03-06,Dark states of dressed spinor Bose-Einstein condensates of spin-1 atoms,"Dressed states of spinor Bose-Einstein condensates of spin-1 atoms located in
optical cavity of near resonance frequency of excited state of the atom are
investigated. The wave function of dark states are given.",0903.1163v1
2010-03-15,New explicit exact solutions for the Liénard equation and its applications,"In this letter, new exact explicit solutions are obtained for the Li\'enard
equation, and the applications of the results to the generalized
Pochhammer-Chree equation, the Kundu equation and the generalized long-short
wave resonance equations are presented.",1003.2921v1
2011-10-19,Pseudo-Hermitian Quantum Dynamics of Tachyonic Spin-1/2 Particles,"We investigate the spinor solutions, the spectrum and the symmetry properties
of a matrix-valued wave equation whose plane-wave solutions satisfy the
superluminal (tachyonic) dispersion relation E^2 = p^2 - m^2, where E is the
energy, p is the spatial momentum, and m is the mass of the particle. The
equation reads (i gamma^mu partial_mu - gamma^5 m) psi = 0, where gamma^5 is
the fifth current. The tachyonic equation is shown to be CP invariant, and T
invariant. The tachyonic Hamiltonian H_5 = alpha.p + beta gamma^5 m breaks
parity and is non-Hermitian but fulfills the pseudo-Hermitian property H_5(r) =
P H^+_5(-r) P^{-1} = PP H^+_5(-r) PP^{-1} where P is the parity matrix and PP
is the full parity transformation. The energy eigenvalues and eigenvectors
describe a continuous spectrum of plane-wave solutions (which correspond to
real eigenvalues for |p|>=m and evanescent waves, which constitute resonances
and antiresonances with complex-conjugate pairs of resonance eigenvalues (for
|p|<=m) . In view of additional algebraic properties of the Hamiltonian which
supplement the pseudo-Hermiticity, the existence of a resonance energy
eigenvalues E implies that E^*, -E, and -E^* also constitute resonance energies
of H_5.",1110.4171v3
2014-06-17,Softening of Granular Packings with Dynamic Forcing,"We perform numerical simulations of a two-dimensional bidisperse granular
packing subjected to both a static confining pressure and a sinusoidal dynamic
forcing applied by a wall on one edge of the packing. We measure the response
experienced by a wall on the opposite edge of the packing and obtain the
resonant frequency of the packing as the static or dynamic pressures are
varied. Under increasing static pressure, the resonant frequency increases,
indicating a velocity increase of elastic waves propagating through the
packing. In contrast, when the dynamic amplitude is increased for fixed static
pressure, the resonant frequency decreases, indicating a decrease in the wave
velocity. This occurs both for compressional and for shear dynamic forcing, and
is in agreement with experimental results. We find that the average contact
number $Z_c$ at the resonant frequency decreases with increasing dynamic
amplitude, indicating that the elastic softening of the packing is associated
with a reduced number of grain-grain contacts through which the elastic waves
can travel. We image the excitations created in the packing and show that there
are localized disturbances or soft spots that become more prevalent with
increasing dynamic amplitude. Our results are in agreement with experiments on
glass bead packings and earth materials such as sandstone and granite, and may
be relevant to the decrease in elastic wave velocities that has been observed
to occur near fault zones after strong earthquakes, in surficial sediments
during strong ground motion, and in structures during earthquake excitation.",1406.4529v1
2019-02-19,Brewster quasi bound states in the continuum in all-dielectric metasurfaces from single magnetic-dipole resonance meta-atoms,"Bound states in the continuum (BICs) are ubiquitous in many areas of physics,
attracting especial interest for their ability to confine waves with infinite
lifetimes. Metasurfaces provide a suitable platform to realize them in
photonics; such BICs are remarkably robust, being however complex to tune in
frequency-wavevector space.Here we propose a scheme to engineer BICs and
quasi-BICs with single magnetic-dipole resonance meta-atoms. Upon changing the
orientation of the magnetic-dipole resonances, we show that the resulting
quasi-BICs,emerging from the symmetry-protected BIC at normal incidence, become
transparent for plane-wave illumination exactly at the magnetic-dipole angle,
due to a Brewster-like effect. While yielding infinite Q-factors at
normalincidence(canonical BIC), these are termed Brewster quasi-BICs since a
transmission channel is always allowed that slightly widens resonances at
oblique incidences. This is demonstrated experimentally through reflectance
measurements in the microwave regime with high-refractive-index mm-disk
metasurfaces. Such Brewster-inspired configuration is a plausible scenario to
achieve quasi-BICs throughout the electromagnetic spectrum inaccessible through
plane-wave illumination at given angles, which could be extrapolated to other
kind of waves.",1902.07148v2
2020-04-15,Millimeter-Wave Huygens' Transmit-Arrays based on Coupled Metallic Resonators,"A novel Huygens' transmit-array is proposed based on a coupled-resonator
approach where two identical elliptical metallic patches with an elliptical
hole separated by a dielectric substrate has been used to demonstrate
millimeter-wave (mm-Wave) beam-forming for linear polarization. The proposed
structure is simple and compatible with standard Printed Circuit Board (PCB)
processes and utilizes a single dielectric substrate only. It is shown that by
engineering the geometrical dimensions of the resonator, its electric
(even-mode) and magnetic (odd-mode) resonances are excited in a balanced manner
to achieve zero back-scattering in a large bandwidth. This operation principle
of the proposed Huygens' cell is explained in details using both an insightful
equivalent circuit model, as well as full-wave eigenmode analysis. Next, the
proposed Huygens' cell is placed on top of a high gain 2D slot-array antenna,
in its near-field, to engineer its aperture field distribution, where the
resulting Huygens' transmit-array acts as a broadband phase plate. Several
transmit-array prototypes designed around the 60 GHz frequency band are
demonstrated and experimentally characterized in both their near and
far-fields, to achieve difference pattern generation, beam expansion and beam
steering as application examples, in addition to a uniform surface
demonstrating its low-loss performance. Further discussions related to the unit
cell size vs frequency bandwidth trade-offs and future extension to handling
circular polarization are finally provided.",2004.07129v1
2017-06-18,The Auger Effect and Ionization of Inner Atomic Shells,"The Auger effect from inner shells, which arises from resonance excitation of
the valence electron of an atom by a weak electromagnetic wave, is discussed.",1706.06465v2
2020-10-07,Primordial black holes and gravitational waves from resonant amplification during inflation,"We present a new realization of the resonant production of primordial black
holes as well as gravitational waves in a two-stage inflation model consisting
of a scalar field \phi with an axion-monodromy-like periodic structure in the
potential that governs the first stage and another field \chi with a
hilltop-like potential that dominates the second stage. The parametric
resonance seeded by the periodic structure at the first stage amplifies the
perturbations of both fields inside the Hubble radius. While the evolution of
the background trajectory experiences a turn as the oscillatory barrier height
increases, the amplified perturbations of \chi remain as they are and
contribute to the final curvature perturbation. It turns out that the
primordial power spectrum displays a significant resonant peak on small scales,
which can lead to an abundant production of primordial black holes.
Furthermore, gravitational waves are also generated from the resonantly
enhanced field perturbations during inflation, the amplitude of which may be
constrained by future gravitational wave interferometers.",2010.03537v2
2021-05-29,Green's functions of and emission into discrete anisotropic and hyperbolic baths,"In this work, we study wave propagation in generic Hermitian local periodic
baths, and investigate the effects of anisotropy and quasi-breaking of
periodicity on resonant emission into the band of the bath. We asymptotically
decompose the Green's function into long-range travelling waves composed of all
wavevectors (near-)resonant at the emitter frequency, and rapidly decaying
evanescent waves. Our approximation then converges exponentially with
increasing source-receiver separation ${\rho}$ when resonant wavepackets with
group velocity parallel to ${\rho}$ exist. In hyperbolic media this condition
may not be satisfied, and we find that the exponential decay length of
oscillating evanescent waves locally around caustics generally depends as a
power law with exponent 3/2 on the angle made between ${\rho}$ and the caustic.
For ${\rho}$ beyond the caustic we observe that the Green's function can become
almost imaginary, which results in exclusively incoherent emitter-emitter
interactions and allows the simulation of purely dissipative systems with
short-range interactions. Here the interaction length is tunable via the
separation vector of the emitters. We finally probe the hyperbolic dispersion
beyond the previous regimes by applying an artificial gauge field on the
lattice. We find that emission resonant with the corresponding open orbits in
the Brillouin zone is quasi-one dimensional, in contrast to an isotropic
environment. The quasi-1D emission is further topologically protected against
local and global lattice perturbations and periodically refocussing, offering a
robust bi-directional transport of excitations in higher-dimensional media.",2105.14238v3
2022-06-22,The Foldy-Lax approximation is valid for nearly resonating frequencies,"The waves (including acoustic, electromagnetic and elastic ones) propagating
in the presence of a cluster of inhomogeneities undergo multiple interactions
between them. When these inhomogeneities have sub-wavelength sizes, the
dominating field due to the these multiple interactions is the Foldy-Lax field.
This field models the interaction between the equivalent point-like scatterers,
located at the centers of the small inhomogeneities, with scattering
coefficients related to geometrical/material properties of each
inhomogeneities, as polarization coefficients. One of the related questions
left open for a long time is whether we can reconstruct this Foldy-Lax field
from the scattered field measured far away from the cluster of the small
inhomogeneities. This is the Foldy-Lax approximation (or Foldy-Lax paradigm).
In this work, we show that this approximation is indeed valid as soon as the
inhomogeneities enjoy critical scales between their sizes and contrasts. These
critical scales allow them to generate resonances which can be characterized
and computed. The main result here is that exciting the cluster by incident
frequencies which are close to the real parts of these resonances allow us to
reconstruct the Fold-Lax field from the scattered waves collected far away from
the cluster itself (as the farfields). In short, we show that the Foldy-Lax
approximation is valid using nearly resonating incident frequencies. This
results is demonstrated by using, as small inhomogeneities, dielectric
nanoparticles for the 2D TM model of electromagnetic waves and bubbles for the
3D acoustic waves.",2206.10899v1
1992-09-11,Spin liquid phase for the frustrated Quantum Heisenberg Antiferromagnet on a square lattice,"The existance of a spin disordered ground state for the frustrated Quantum
Heisenberg Antiferromagnet on a square lattice is reconsidered. It is argued
that there is a unique action which is continuous through the whole phase
diagram, except at the Lifshitz point, so that the Neel and helicoidal states
can not coexist and there has to be an intermediate spin liquid state. To show
it, a detailed study combining Spin-Wave theory, Schwinger Bosons Mean Field
Theory and a scaling analysis of the appropriate hydrodynamic action is
performed. When done carefully, all these theories agree and strongly support
the existance of the spin liquThe manuscript has eight figures, which are
available upon request to the author. e-mail address is
ferrer@physics.rutgers.edu",9209009v1
1994-05-09,One-Dimensional Kondo Lattice at Half Filling: Charge Properties,"The model of Kondo chain with $M$-fold degenerate band of conduction
electrons of spin 1/2 at half filling interacting with localized spins $S$ is
studied. It is shown that due to the instanton effects the spin sector reveals
itself in optical conductivity. Namely, the density of the charge current at
large wave vector $k \approx \pi$ is proportional to the density of topological
charge of the staggered magnetization. As a consequence, the optical
conductivity at $k = \pi$ would either have a gap equal to three spin gaps (for
$|M - 2S| = $(even) when the spin spectrum is gapful), or show a psedogap
$\sigma(\omega, k = \pi) \sim \omega^2$ for $|M - 2S|$ = (odd).",9405024v1
1997-12-02,Mixed spin ladders with exotic ground states,"We study the ""mixed spin"" isotropic ladder system having S=1 spins on one leg
and S=1/2 spins on the other, with general-type exchange interactions between
spins on neighboring rungs. A set of model Hamiltonians with exact ground
states in the form of a certain matrix product wave function is obtained. We
show that sufficiently strong frustration can lead to exotic singlet ground
states with infinite (exponential) degeneracy. We also list a couple of rather
simple models with nontrivial ground states, including a model with only
bilinear exchange.",9712022v1
1998-03-12,Frustrated quantum Heisenberg ferrimagnetic chains,"We study the ground-state properties of weakly frustrated Heisenberg
ferrimagnetic chains with nearest and next-nearest neighbor antiferromagnetic
exchange interactions and two types of alternating sublattice spins S_1 > S_2,
using 1/S spin-wave expansions, density-matrix renormalization group, and
exact- diagonalization techniques. It is argued that the zero-point spin
fluctuations completely destroy the classical commensurate- incommensurate
continuous transition. Instead, the long-range ferrimagnetic state disappears
through a discontinuous transition to a singlet state at a larger value of the
frustration parameter. In the ferrimagnetic phase we find a disorder point
marking the onset of incommensurate real-space short-range spin-spin
correlations.",9803150v1
1998-10-05,Quantum critical point with competing propagating and diffusive spin excitations,"Feedback effects due to spin fluctuation induced precursors in the fermionic
quasiparticle spectrum are taken into account in the description of a quantum
critical point of itinerant spin systems. A correlation length dependent spin
damping occurs, leading to a dynamical scaling with z\approx 1 which
non-trivially competes with the conventional spin wave behavior. We obtain,
within a one loop renormalization group approach, a quantitative explanation
for the scaling behavior seen in underdoped cuprate superconductors.",9810041v1
1999-09-01,Dynamic spin susceptibility in the t-J model,"Dynamic spin susceptibility is calculated for the t-J model in the
paramagnetic phase by applying the memory function method in terms of the
Hubbard operators. A self-consistent system of equations for the memory
function is obtained within the mode coupling approximation. Both itinerant
hole excitations and localized spin fluctuations give contributions to the
memory function. Spin dynamics have a diffusive character in the hydrodynamic
limit; spin-wave-like excitations are regained in the high-frequency region.",9909019v1
2000-02-01,Rashba spin splitting in two-dimensional electron and hole systems,"In two-dimensional (2D) hole systems the inversion asymmetry induced spin
splitting differs remarkably from its familiar counterpart in the conduction
band. While the so-called Rashba spin splitting of electron states increases
linearly with in-plane wave vector k_|| the spin splitting of heavy hole states
can be of third order in k_|| so that spin splitting becomes negligible in the
limit of small 2D hole densities. We discuss consequences of this behavior in
the context of recent arguments on the origin of the metal-insulator transition
observed in 2D systems.",0002003v1
2001-07-24,Analytical expressions for the spin-spin local-field factor and the spin-antisymmetric exchange-correlation kernel of a two-dimensional electron gas,"We present an analytical expression for the static many-body local field
factor $G_{-}(q)$ of a homogeneous two-dimensional electron gas, which
reproduces Diffusion Monte Carlo data and embodies the exact asymptotic
behaviors at both small and large wave number $q$. This allows us to also
provide a closed-form expression for the spin-antisymmetric exchange and
correlation kernel $K^{-}_{xc}(r)$ which represents a key input for
spin-density functional studies of inhomogeneous electronic systems.",0107501v1
2001-12-29,Longitudinal spin waves in a dilute Bose gas,"We present a kinetic theory for a dilute noncondensed Bose gas of two-level
atoms that predicts the transient spin segregation observed in a recent
experiment. The underlying mechanism driving spin currents in the gas is due to
a mean field effect arising from the quantum interference between the direct
and exchange scattering of atoms in different spin states. We numerically solve
the spin Boltzmann equation, using a one dimensional model, and find excellent
agreement with experimental data.",0112487v1
2003-08-29,Magnetic Order and Dynamics in Stripe-Ordered La2-xSrxNiO4,"We have studied magnetic correlations in several compositions of
stripe-ordered La2-xSrxNiO4. In this paper we show how polarized-neutron
scattering has helped uncover important features of the magnetic ordering and
spin dynamics. In particular, polarization analysis has enabled us (1) to
characterize a spin reorientation transition, (2) to identify anisotropy gaps
in the spin excitation spectrum, and (3) to investigate an anomalous dip in the
spin-wave intensity suggestive of coupling between collective spin and charge
excitations.",0308631v1
2003-10-01,Rashba coupling in quantum dots: exact solution,"We present an analytic solution to the problem of the Rashba spin-orbit
coupling in semiconductor quantum dots. We calculate the exact energy spectrum,
wave-functions, and spin--flip relaxation times. We discuss various effects
inaccessible via perturbation theory. In particular, we find that the effective
gyromagnetic ratio is strongly suppressed by the spin-orbit coupling. The
spin-flip relaxation rate has a maximum as a function of the spin-orbit
coupling and is therefore suppressed in both the weak- and strong coupling
limits.",0310024v2
2005-08-31,Order by disorder and gauge-like degeneracy in quantum pyrochlore antiferromagnet,"The (three-dimensional) pyrochlore lattice antiferromagnet with Heisenberg
spins of large spin length $S$ is a highly frustrated model with an macroscopic
degeneracy of classical ground states. The zero-point energy of (harmonic
order) spin wave fluctuations distinguishes a subset of these states. I derive
an approximate but illuminating {\it effective Hamiltonian}, acting within the
subspace of Ising spin configurations representing the {\it collinear} ground
states. It consists of products of Ising spins around loops, i.e has the form
of a $Z_2$ lattice gauge theory. The remaining ground state entropy is still
infinite but not extensive, being $O(L)$ for system size $O(L^3)$. All these
ground states have unit cells bigger than those considered previously.",0509005v1
2006-06-15,Optical spin pumping of modulation doped electrons probed by a two-color Kerr rotation technique,"We report on optical spin pumping of modulation electrons in CdTe-based
quantum wells with low intrinsic electron density (by 10^10 cm^{-2}). Under
continuous wave excitation, we reach a steady state accumulated spin density of
about 10^8 cm^{-2}. Using a two-color Hanle-MOKE technique, we find a spin
relaxation time of 34 ns for the localized electrons in the nearly unperturbed
electron gas. Independent variation of the pump and probe energies demonstrates
the presence of additional non-localized electrons in the quantum well, whose
spin relaxation time is substantially shorter.",0606419v1
2006-07-04,Scattering induced spin orientation and spin currents in gyrotropic structures,"It is shown that additional contributions both to current-induced spin
orientation and to the spin Hall effect arise in quantum wells due to gyrotropy
of the structures. Microscopically, they are related to basic properties of
gyrotropic systems, namely, linear in the wave vector terms in the matrix
element of electron scattering and in the energy spectrum. Calculation shows
that in high-mobility structures the contribution to the spin Hall current
considered here can exceed the term originated from the Mott skew scattering.",0607074v1
2006-07-08,Harper-Hofstadter problem for 2D electron gas with ${\bf k}$-linear Rashba spin-orbit coupling,"The Harper-Hofstadter problem for two-dimensional electron gas with Rashba
spin-orbit coupling subject to periodic potential and perpendicular magnetic
field is studied analytically and numerically. The butterfly-like energy
spectrum, spinor wave functions as well as the spin density and average spin
polarization are calculated for actual parameters of semiconductor structure.
Our calculations show that in two-dimensional electron gas subject to periodic
potential and uniform magnetic field the effects of energy spectrum splitting
caused by large spin-orbit Rashba coupling can be observed experimentally.",0607216v1
2007-03-08,Spin transverse force and quantum transverse transport,"We present a brief review on spin transverse force, which exerts on the spin
as the electron is moving in an electric field. This force, analogue to the
Lorentz force on electron charge, is perpendicular to the electric field and
spin current carried by the electron. The force stems from the spin-orbit
coupling of electrons as a relativistic quantum effect, and could be used to
understand the Zitterbewegung of electron wave packet and the quantum
transverse transport of electron in a heuristic way.",0703196v1
2001-04-24,Extra Spin-Rotation Coupling Effect in a Radiating Kerr Space-time,"Source-less wave equations are derived for massless scalar, neutrino and
electromagnetic perturbations of a radiating Kerr space-time, and the Hawking
radiation of massless particles with spin $s =0, 1/2$ and 1 in this geometry is
investigated by using a method of the generalized tortoise coordinate
transformation. An extra interaction between the spin of particles and the
rotation of the hole displays in the thermal spectra of Hawking radiation of
massless particles with spin $s = 1/2, 1$ in the evaporating Kerr space-time.
The character of such effect is its obvious dependence on different helicity
states of particles with higher spin.",0104074v1
2006-04-21,The Hyperfine Einstein-Infeld-Hoffmann Potential,"We use recently developed effective field theory techniques to calculate the
third order post-Newtonian correction to the spin-spin potential between two
spinning objects. This correction represents the first contribution to the
spin-spin interaction due to the non-linear nature of general relativity and
will play an important role in forthcoming gravity wave experiments.",0604099v1
1997-12-11,Greybody Factors for Black Holes in Four Dimensions: Particles with Spin,"We compute the emission spectrum of minimally coupled particles with spin
that are Hawking radiated from four dimensional black holes in string theory.
For a range of the black hole parameters the result has a product structure
that may be interpreted in terms of the respective right- and left-moving
thermal correlation functions of an effective string model. For spin-one and
spin-two particles a novel cancellation between contributions to the wave
function is needed to ensure this outcome. The form of the spectra suggests
that the four-dimensional effective string description is ``heterotic'':
particles with spin are emitted from the right-moving sector, only.",9712118v1
2005-09-13,The continuous spin limit of higher spin field equations,"We show that the Wigner equations describing the continuous spin
representations can be obtained as a limit of massive higher-spin field
equations. The limit involves a suitable scaling of the wave function, the mass
going to zero and the spin to infinity with their product being fixed. The
result allows to transform the Wigner equations to a gauge invariant
Fronsdal-like form. We also give the generalisation of the Wigner equations to
higher dimensions with fields belonging to arbitrary representations of the
massless little group.",0509092v2
2005-04-08,Spin as the Basis for Quantum Mechanics: A New Semiclassical Model for Electron Spin,"A simple real-space model for the free-electron wavefunction with spin is
proposed, based on coherent vortices on the scale of h/mc, rotating at mc^2/h.
This reproduces the proper values for electron spin and magnetic moment.
Transformation to a moving reference frame turns this into a wave with the de
Broglie wavelength. The mapping of the real two-dimensional vector phasor to
the complex plane satisfies the Schrodinger equation. This suggests a
fundamental role for spin in quantum mechanics.",0504068v1
2007-06-13,Bispinor Formulation of Spin 3/2 Field Theory,"In this paper, we investigate an alternative formulation for spin 3/2 field
equation. First we will review equation of motion of Dirac and Maxwell, and
then construct the equation for spin 3/2 in the similar fashion. Our method
actually a generalization of relativistic equation of motion based on spin
operator and Hamiltonian similar to Dirac and Maxwell equation in ref. [1] pp.
50. Furthermore, we could not bring the equation to the Klein Gordon limit for
every wave function component in spin 3/2 formalism.",0706.1910v4
2007-12-07,Scattering of Spin-Zero and Spin-Half Particles in Momentum-Helicity Basis,"Scattering of 2 particles of spin 0 and 1/2 is evaluated based on a basis
constructed from the momentum and the helicity states (the momentum-helicity
basis). This shortly called three-dimensional (3D) technique is a good
alternative to the standard partial wave (PW) technique especially for higher
energies, where PW calculations may become not feasible. Taking as input a
simple spin-orbit potential model we calculate as an example the spin averaged
differential cross section and polarization.",0712.1101v1
2008-11-11,"Spin susceptibility, phase diagram, and quantum criticality in the electron-doped high Tc Superconductor Ba[Fe(1-x)Co(x)]2As2","We report a systematic investigation of Ba[Fe(1-x)Co(x)]2As2 based on
transport and 75-As NMR measurements, and establish the electronic phase
diagram. We demonstrate that doping progressively suppresses the uniform spin
susceptibility and low frequency spin fluctuations. The optimum superconducting
phase emerges at x_c~0.08 when the tendency toward spin ordering completely
diminishes. Our findings point toward the presence of a quantum critical point
near x_c between the SDW (spin density wave) and superconducting phases.",0811.1617v1
2008-11-13,Cooling into the Spin-Nematic State for a Spin-1 Bose gase in an optical lattice,"The possibility of adiabatically cooling a spin-1 polar Bose gas to a
spin-nematic phase is theoretically discussed. The relation between the order
parameter of the final spin-nematic phase and the starting temperature of the
spinor Bose gas is obtained both using the mean-field approach for the high
temperature and spin-wave approach for the low temperature. We find that there
exists a good possibility to reach the spin-nematic ordering starting with
spinor antiferromagnetic Bose gases.",0811.2054v1
2008-11-28,Effect of Nonlocal Spin-Transfer Torque on Current-Induced Magnetization Dynamics,"Using the self-consistent model, we present nonlocal spin-transfer effects
caused by the feedback between inhomogeneous magnetization and spin-transfer
torque on the current-induced magnetization dynamics in nanomagnets. The
nonlocal effects can substantially improve the coherence time of precession in
nanomagnets and thus reduce the linewidth of power spectrum. This narrow
linewidth results from the nonlinear damping of spin-waves due to the nonlocal
spin torque which is inherent and thus should be considered in future
experiments.",0811.4649v1
2009-09-15,Critical current density for spin transfer torque switching with composite free layer structure,"Critical current density of composite free layer (CFL) in magnetic tunneling
junction is investigated. CFL consists of two exchange coupled ferromagnetic
layers, where the coupling is parallel or anti-parallel. Instability condition
of the CFL under the spin transfer torque, which is related with critical
current density, is obtained by analytic spin wave excitation model and
confirmed by macro-spin Landau-Lifshitz-Gilbert equation. The critical current
densities for the coupled two identical layers are investigated with various
coupling strengths, and spin transfer torque efficiencies.",0909.2711v1
2009-10-13,Boltzmann theory of magnetoresistance due to a spin spiral,"We studied the magnetoresistance due to a spin spiral by solving the
Boltzmann equation. The scattering rates of conduction electrons are calculated
by using the non-perturbative wave function of the conduction electrons and the
non-equilibrium distribution function is obtained by numerically solving the
Boltzmann equation. These enable us to calculate the resistivity of a
sufficiently thin spin spiral. A magnetoresistance ratio of more than 50% is
predicted for a spin spiral with high spin polarization (>0.8) and a small
period (about 1-2 nm).",0910.2308v2
2010-08-06,Ferromagnetic phases in spin-Fermion systems,"Spin-Fermion systems which obtain their magnetic properties from a system of
localized magnetic moments being coupled to conducting electrons are
considered. The dynamical degrees of freedom are spin-$s$ operators of
localized spins and spin-1/2 Fermi operators of itinerant electrons.
Renormalized spin-wave theory, which accounts for the magnon-magnon
interaction, and its extension are developed to describe the two ferrimagnetic
phases in the system: low temperature phase $0<T<T^{*}$, where all electrons
contribute the ordered ferromagnetic moment, and high temperature phase
$T^{*}<T<T_C$, where only localized spins form magnetic moment. The
magnetization as a function of temperature is calculated. The theoretical
predictions are utilize to interpret the experimentally measured
magnetization-temperature curves of $UGe_2$..",1008.1148v1
2010-10-26,Spin Fidelity for Three-qubit Greenberger-Horne-Zeilinger and W States Under Lorentz Transformations,"Constructing the reduced density matrix for a system of three massive
spin$-\frac{1}{2}$ particles described by a wave packet with Gaussian momentum
distribution and a spin part in the form of GHZ or W state, the fidelity for
the spin part of the system is investigated from the viewpoint of moving
observers in the jargon of special relativity. Using a numerical approach, it
turns out that by increasing the boost speed, the spin fidelity decreases and
reaches to a non-zero asymptotic value that depends on the momentum
distribution and the amount of momentum entanglement.",1010.5330v1
2012-03-27,Spin dynamics in the Kapitza-Dirac effect,"Electron spin dynamics in Kapitza-Dirac scattering from a standing laser wave
of high frequency and high intensity is studied. We develop a fully
relativistic quantum theory of the electron motion based on the time-dependent
Dirac equation. Distinct spin dynamics, with Rabi oscillations and complete
spin-flip transitions, is demonstrated for Kapitza-Dirac scattering involving
three photons in a parameter regime accessible to future high-power X-ray laser
sources. The Rabi frequency and, thus, the diffraction pattern is shown to
depend crucially on the spin degree of freedom.",1204.0239v2
2013-02-14,Spin-Hall Conductivity and Electric Polarization in Metallic Thin Films,"We predict theoretically that, when a normal metallic thin film (without bulk
spin-orbit coupling, such as Cu or Al) is sandwiched by two insulators, two
prominent effects arise due to the interfacial spin-orbit coupling: a giant
spin-Hall conductivity due to the surface scattering and a transverse electric
polarization due to the spin-dependent phase shift in the spinor wave
functions.",1302.3490v2
2013-06-25,Designing a Spin-Seebeck Diode,"Using micromagnetic simulations, we have investigated spin dynamics in a
spin-valve bi-layer in the presence of a thermal gradient. The direction and
the intensity of the gradient allow to excite the spin wave modes of each layer
selectively. This permits to synchronize the magnetization precession of the
two layers and to rectify the flows of energy and magnetization through the
system. Our study yields promising opportunities for applications in spin
caloritronics and nanophononics devices.",1306.5924v2
2014-01-27,Spin chains and classical strings in rotating Rindler-AdS space,"In this paper, we study the spin chain and string excitation in the rotating
Rindler-$AdS_3$ proposed in [12]. We obtain a one-parameter deformed $SL(2)$
spin chain at the fast spin limit. Two-spin GKP-like solutions are studied at
short and long string limits. General ansatz for the giant magnons and the
spiky strings are analyzed in detail for various $\beta$. At last, we explore
its counterpart in analytic continuation and pp-wave limit.",1401.6915v1
2014-03-17,Massive twistor particle with spin generated by Souriau-Wess-Zumino term and its quantization,"We present new model of D=4 relativistic massive particle with spin and we
describe its quantization. The model is obtained by an extension of standard
relativistic phase space description of massive spinless particle by adding new
topological Souriau-Wess-Zumino term which depends on spin fourvector variable.
We describe equivalently our model as given by the free two-twistor action with
suitable constraints. An important tool in our derivation is the spin-dependent
twistor shift, which modifies standard Penrose incidence relations. The
quantization of the model provides the wave function with correct mass and spin
eigenvalues.",1403.4127v1
2019-11-05,Spin chains and classical strings in two parameters $q$-deformed AdS$_3\times$S$^3$,"In this paper, we study the spin chain and string excitation in the
two-parameters $q$-deformed AdS$_3\times$S$^3$ proposed by Hoare. We obtain the
deformed spin chain model at the fast spin limit for choices of deformed
parameters. General ansatz for giant magnons are studied in great detail and
complicated dispersion relation is treated perturbatively. We also study
several types of hanging string solutions and their charges and spins are
analyzed numerically. At last, we explore its pp-wave limit and find its
solution only depends on the difference of deformed parameters.",1911.01567v1
2012-09-20,Quench dynamics in spin crossover induced by high pressure,"In this paper we have studied analytically and numerically dynamics of spin
crossover induced by time-dependent pressure. We show that quasi static
pressure, with a slow dependence on time, yields a spin crossover leading to
transition from the state of quantum system with high spin (HS) to the low spin
(LS). However, a quench dynamics under shock-wave load is more complicated. The
final state of the system depends on the amplitude and pulse velocity,
resulting in the mixture of the HS and LS states.",1209.4567v1
2018-02-21,Spin-fluctuations drive the inverse magnetocaloric effect in Mn5Si3,"Inelastic neutron scattering measurements were performed on single crystals
of the antiferromagnetic compound Mn5Si3 in order to investigate the relation
between the spin dynamics and the magneto-thermodynamic properties. It is shown
that among the two stable antiferromagnetic phases of this compound, the high
temperature one has an unusual magnetic excitation spectrum where propagative
spin-waves and diffuse spin-fluctuations coexist. Moreover, it is evidenced
that the inverse magnetocaloric effect of Mn5Si3, the cooling by adiabatic
magnetization, is associated with field induced spin-fluctuations.",1802.07511v1
2019-02-11,Magnon excitations in $Cs_2CuAl_4O_8$ - a bond alternating S=1/2 spin chain with next nearest neighbor coupling,"A recent density functional theory (DFT) based analysis, complemented with
Quantum Monte Carlo calculations revealed a highly spin-frustrating nature of
the one-dimensional spin-$\frac{1}{2}$ compound $Cs_2CuAl_4O_8$ that comprises
of unique bond alternations and relatively strong next nearest neighbor
interactions. This article gives a brief account on possible magnon excitations
that can appear in the ground state of such systems. We find that the spin
waves obtained on top of coplanar helical reference states show multiple magnon
modes (both acoustic and optical). However, those magnon modes turn out to be
stable only in the absence of bond alternations.",1902.04008v1
2008-06-19,Anomalous Spin Response in Non-centrosymmetric Compounds,"We examine static spin susceptibilities $\chi_{\alpha\beta}({\bf q})$ of spin
components $S_{\alpha}$ and $S_{\beta}$ in the non-centrosymmetric tetragonal
system. These show anomalous momentum dependences like $\chi_{xx}({\bf
q})-\chi_{yy}({\bf q})\sim q_x^2-q_y^2$ and $\chi_{xy}({\bf q})+\chi_{yx}({\bf
q})\sim q_x q_y$, which vanish in centrosymmetric systems. The magnitudes of
the anomalous spin susceptibilities are enhanced by the on-site Coulomb
interaction, especially, around an ordering wave vector. The significant and
anomalous momentum dependences of these susceptibilities are explained by a
group theoretical analysis. As the direct probe of the anomalous spin
susceptibility, we propose a polarized neutron scattering experiment.",0806.3214v1
2019-12-09,Double-$Q$ Chiral Stripe in the $d$-$p$ Model with Strong Spin-Charge Coupling,"We investigate the stability of multiple-$Q$ spiral states in $d$-$p$
electron systems with the strong spin-charge coupling. By using variational
calculations on a square lattice, we find that the double-$Q$ state with the
scalar chirality density wave, which has been studied in the weak spin-charge
coupling regime, becomes the ground state even in the strong spin-charge
coupling regime by considering the effect of the $d$-$p$ hybridization. We also
show that the regions where the double-$Q$ state is stabilized are widely
extended for introducing the antiferromagnetic superexchange interaction
between nearest-neighbor localized spins.",1912.03906v1
2022-02-23,General Spin Sums in Quantum Field Theory,"In Quantum Field Theory, scattering amplitudes are computed from propagators
which, for internal lines, are built upon spin/polarization-sum relationships.
In turn, these are normally constructed upon plane-wave solutions of the free
field equations. A question that may now arise is whether such
spin/polarization-sums can be generalized. In the past, there has been a first
attempt at generalizing spin sums for fermionic fields in terms of the
Michel-Wightman identities. In this paper, we aim to find the most general spin
sums for fermionic fields within the range of QFT.",2203.04087v3
2022-05-30,Fledgling quantum spin Hall effect in pseudo gap phase of Bi2212,"We study the emergence of the quantum spin Hall (QSH) states for the
pseudo-gap (PG) phase of Bi2212 bilayer system, assumed to be D-density
wave(DDW) ordered, starting with a strong Rashba spin-orbit coupling(SOC)
armed, and the time reversal symmetry (TRS) complaint Bloch Hamiltonian. The
presence of strong SOC gives rise to non-trivial, spin-momentum locked spin
texture tunable by electric field. The emergence of quantum anomalous Hall
effect with TRS broken Chiral DDW Hamiltonian of Das Sarma et al. is found to
be possible.",2205.15010v1
2023-06-02,Chiral electrons and spin selectivity at chiral-achiral interfaces,"Chiral molecules can selectively transport electrons of a particular spin
orientation, yet the underlying mechanism remain poorly understood. Here, we
present theoretical evidence that electrons propagating through chiral
materials with screw symmetry exhibit chirality themselves and carry
symmetry-induced pseudo-angular momentum (PAM) which must be characterized by
both spin and orbital components. The chiral electron transport is PAM
polarized, with counterpropagating states exhibiting opposite PAM. At
chiral-achiral interfaces, the PAM polarization is converted to spin
polarization due to wave function matching, thereby establishing a novel
principle for the chiral-induced spin selectivity.",2306.01664v2
2023-07-31,Spin-frame field theory of a three-sublattice antiferromagnet,"We present a nonlinear field theory of a three-sublattice hexagonal
antiferromagnet. The order parameter is the spin frame, an orthogonal triplet
of vectors related to sublattice magnetizations and spin chirality. The
exchange energy, quadratic in spin-frame gradients, has three coupling
constants, only two of which manifest themselves in the bulk. As a result, the
three spin-wave velocities satisfy a universal relation. Vortices generally
have an elliptical shape with the eccentricity determined by the Lam\'e
parameters.",2307.16853v2
2023-08-31,Schwinger boson symmetric spin liquids of Shastry-Sutherland model,"Motivated by recent experimental and numerical evidences of deconfined
quantum critical point and quantum spin-liquid states in spin-$1/2$ Heisenberg
model on Shastry-Sutherland lattice, we studied possible symmetric spin liquid
states and their proximate ordered states under Schwinger boson formalism. We
found a symmetric gapped $Z_2$ spin-liquid state for intermediate model
parameter $0.66 < J_1/J_2 < 0.71$ under mean-field approximation. The Schwinger
boson mean-field picture is partially supported by exact-diagonalization and
self-consistent spin wave theory results.",2308.16563v3
2023-12-13,Cubic action for Spinning Black Holes from massive higher-spin gauge symmetry,"Scattering of two Kerr Black Holes emitting gravitational waves can be
captured by an effective theory of a massive higher-spin field interacting with
the gravitational field. While other compact objects should activate a
multitude of non-minimal interactions it is the black holes that should be
captured by the simplest minimal interaction. Implementing massive higher-spin
symmetry via a string-inspired BRST approach we construct an action that
reproduces the correct cubic amplitude of Arkani-Hamed--Huang--Huang. The same
is achieved for the root-Kerr theory, i.e. for the minimal electromagnetic
interaction of a massive higher-spin field.",2312.08184v1
2012-12-10,An empirical study on a learning path on wave physics focused on energy,"We describe an extracurricular learning path on waves focused on energy
transfer. The advantages of introducing mechanical waves by using the Shive
wave machine and laboratory activities are presented. Laboratories are realized
by inquiry, i.e. students explore waves behavior in qualitative way, guess what
can happen and suddenly test their hypothesis. Recently, we presented some
disciplinary knots that arise usually in empirical investigation, according to
the Model of Educational Reconstruction and discussed methodological choices
made in designing the learning path and preliminary result about its
realization with few, interested and talented pupils. We report the second year
of this learning path performed with the same students that are introduced to
more complex topics such as analogy in wave phenomena and resonance.
Laboratories are described with particular attention for the energy
transformation. We designed the activities in order to propose a complementary
experience compared to what was done in class. Despite resonance is a relevant
phenomenon which runs through almost every branch of physics, many students
have never studied it. Yet, resonance is one of the most striking and
unexpected phenomenon in all physics and it easy to observe but difficult to
understand. Students performed activities in laboratory on several resonant
systems. Our purpose was to outline how it is possible to tune a system or a
device in order to obtain resonance and an efficient energy transfer from
different physical systems, such as a mechanical one and an electrical one.
This year, the final task was to analyze different natural phenomena in order
of choosing one suitable for energy transfer. We present our considerations on
the students' learning process and on the possibility of extend a similar path
in a classroom.",1212.2174v1
2017-11-12,Double plasma resonance instability as a source of solar zebra emission,"The double plasma resonance (DPR) instability plays a basic role in the
generation of solar radio zebras. In the plasma, consisting of the loss-cone
type distribution of hot electrons and much denser and colder background
plasma, this instability generates the upper-hybrid waves, which are then
transformed into the electromagnetic waves and observed as radio zebras. In the
present paper we numerically study the double plasma resonance instability from
the point of view of the zebra interpretation. We use a 3-dimensional
electromagnetic particle-in-cell (3-D PIC) relativistic model. First using the
multi-mode model, we study details of the double plasma resonance instability.
We show how the distribution function of hot electrons changes during this
instability. Then we show that there is a very good agreement between results
obtained by the multi-mode and specific-mode models, which is caused by a
dominance of the wave with the maximal growth rate. Therefore, for computations
in a broad range of model parameters, we use the specific-mode model. We
compute the maximal growth rates of the double plasma resonance instability.
The results are compared with the analytical ones. We find a very good
agreement between numerical and analytical growth rates. We also compute
saturation energies of the upper-hybrid waves in a very broad range of
parameters. We find that the saturation energies of the upper-hybrid waves show
maxima and minima at almost the same values of
$\omega_\mathrm{UH}/\omega_\mathrm{ce}$ as the growth rates. Furthermore, we
find that the saturation energy of the upper-hybrid waves is proportional to
the density of hot electrons. The maximum saturated energy can be up to one
percent of the kinetic energy of hot electrons. All these findings can be used
in the interpretation of solar radio zebras.",1711.04281v1
2005-01-26,High-field ESR studies of the quantum spin magnet CaCu2O3,"We report an electron spin resonance (ESR) study of the s=1/2-Heisenberg
pseudo-ladder magnet CaCu2O3 in pulsed magnetic fields up to 40 T. At
sub-Terahertz frequencies we observe an ESR signal originating from a small
amount of uncompensated spins residing presumably at the imperfections of the
strongly antiferromagnetically correlated host spin lattice. The data give
evidence that these few percent of ''extra'' spin states are coupled strongly
to the bulk spins and are involved in the antiferromagnetic ordering at T_N =
25 K. By mapping the frequency/resonance field diagram we have determined a
small gap for magnetic excitations below T_N of the order of 0.3 - 0.8 meV.
Such a small value of the gap explains the occurrence of the spin-flop
transition in CaCu2O 3 at weak magnetic fields H_{sf} ~ 3 T. Qualitative
changes of the ESR response with increasing the field strength give indications
that strong magnetic fields reduce the antiferromagnetic correlations and may
even suppress the long-range magnetic order in CaCu2O3. ESR data support
scenarios with a significant role of the ''extra'' spin states for the
properties of low-dimensional quantum magnets.",0501647v3
2005-12-05,"Twin spin/charge roton mode and superfluid density: primary determining factors of $T_{c}$ in high-$T_{c}$ superconductors observed by neutron, ARPES, and $μ$SR","In the quest for primary factors which determine the transition temperature
$T_{c}$ of high-$T_{c}$ cuprate superconductors (HTSC), we develop a
phenomenological picture combining experimental results from muon spin
relaxation ($\mu$SR), neutron and Raman scattering, and angle-resolved
photoemission (ARPES) measurements, guided by an analogy with superfluid
$^{4}$He. The 41 meV neutron resonance mode and the ARPES superconducting
coherence peak (SCP) can be viewed as direct observations of spin and charge
soft modes, respectively, appearing near ($\pi,\pi$) and the center of the
Brillouin zone, having identical energy transfers and dispersion relations. We
present a conjecture that the mode energy of this twin spin/charge collective
excitation, as a roton analogue in HTSC, plays a primary role in determining
$T_{c}$, together with the superfluid density $n_{s}/m^{*}$ at $T \to 0$. We
further propose a microscopic model for pairing based on a resonant spin-charge
motion, which explains the extremely strong spin-charge coupling, relevant
energy scales, disappearence of pairing in the overdoped region, and the
contrasting spin-sensitivities of nodal and antinodal charges in HTSC systems.
Comparing collective versus single-particle excitations, pair formation versus
condensation, and local versus long-range phase coherence, we argue that many
fundamental features of HTSC systems, including the region of the Nernst
effect, can be understood in terms of condensation and fluctuation phenomena of
bosonic correlations formed above $T_{c}$.",0512075v1
2007-05-16,"Quantum spin liquid states in the two dimensional kagome antiferromagnets, ZnxCu4-x(OD)6Cl2","A three-dimensional system of interacting spins typically develops static
long-range order when it is cooled. If the spins are quantum (S = 1/2),
however, novel quantum paramagnetic states may appear. The most highly sought
state among them is the resonating valence bond (RVB) state in which every pair
of neighboring quantum spins form entangled spin singlets (valence bonds) and
the singlets are quantum mechanically resonating amongst all the possible
highly degenerate pairing states. Here we provide experimental evidence for
such quantum paramagnetic states existing in frustrated antiferromagnets,
ZnxCu4-x(OD)6Cl2, where the S = 1/2 magnetic Cu2+ moments form layers of a
two-dimensional kagome lattice. We find that in Cu4(OD)6Cl2, where distorted
kagome planes are weakly coupled to each other, a dispersionless excitation
mode appears in the magnetic excitation spectrum below ~ 20 K, whose
characteristics resemble those of quantum spin singlets in a solid state, known
as a valence bond solid (VBS), that breaks translational symmetry. Doping
nonmagnetic Zn2+ ions reduces the distortion of the kagome lattice, and weakens
the interplane coupling but also dilutes the magnetic occupancy of the kagome
lattice. The VBS state is suppressed and for ZnCu3(OD)6Cl2 where the kagome
planes are undistorted and 90% occupied by the Cu2+ ions, the low energy spin
fluctuations in the spin liquid phase become featureless.",0705.2279v1
2009-05-04,$T_1$- and $T_2$-spin relaxation time limitations of phosphorous donor electrons near crystalline silicon to silicon dioxide interface defects,"A study of donor electron spins and spin--dependent electronic transitions
involving phosphorous ($^{31}$P) atoms in proximity of the (111) oriented
crystalline silicon (c-Si) to silicon dioxide (SiO$_{2}$) interface is
presented for [$^{31}$P] = 10$^{15}$ $\mathrm{cm}^{-3}$ and [$^{31}$P] =
10$^{16}$ $\mathrm{cm}^{-3}$ at about liquid $^4$He temperatures ($T = 5$
$\mathrm{K} - 15$ $\mathrm{K}$). Using pulsed electrically detected magnetic
resonance (pEDMR), spin--dependent transitions between the \Phos donor state
and two distinguishable interface states are observed, namely (i) \Pb centers
which can be identified by their characteristic anisotropy and (ii) a more
isotropic center which is attributed to E$^\prime$ defects of the \sio bulk
close to the interface. Correlation measurements of the dynamics of
spin--dependent recombination confirm that previously proposed transitions
between \Phos and the interface defects take place. The influence of these
electronic near--interface transitions on the \Phos donor spin coherence time
$T_2$ as well as the donor spin--lattice relaxation time $T_1$ is then
investigated by comparison of spin Hahn--echo decay measurements obtained from
conventional bulk sensitive pulsed electron paramagnetic resonance and surface
sensitive pEDMR, as well as surface sensitive electrically detected inversion
recovery experiments. The measurements reveal that both $T_2$ and $T_1$ of
\Phos donor electrons spins in proximity of energetically lower interface
states at $T\leq 13$ K are reduced by several orders of magnitude.",0905.0416v1
2012-07-16,Decoherence mechanisms of 209Bi donor electron spins in isotopically pure 28Si,"Bismuth (209Bi) is the deepest Group V donor in silicon and possesses the
most extreme characteristics such as a 9/2 nuclear spin and a 1.5 GHz hyperfine
coupling. These lead to several potential advantages for a Si:Bi donor electron
spin qubit compared to the more common phosphorus donor. Previous studies on
Si:Bi have been performed using natural silicon where linewidths and electron
spin coherence times are limited by the presence of 29Si impurities. Here we
describe electron spin resonance (ESR) and electron nuclear double resonance
(ENDOR) studies on 209Bi in isotopically pure 28Si. ESR and ENDOR linewidths,
transition probabilities and coherence times are understood in terms of the
spin Hamiltonian parameters showing a dependence on field and mI of the 209Bi
nuclear spin. We explore various decoherence mechanisms applicable to the donor
electron spin, measuring coherence times up to 700 ms at 1.7 K at X-band,
comparable with 28Si:P. The coherence times we measure follow closely the
calculated field-sensitivity of the transition frequency, providing a strong
motivation to explore 'clock' transitions where coherence lifetimes could be
further enhanced.",1207.3776v3
2014-08-27,Dynamics of a mesoscopic nuclear spin ensemble interacting with an optically driven electron spin,"The ability to discriminate between simultaneously occurring noise sources in
the local environment of semiconductor InGaAs quantum dots, such as electric
and magnetic field fluctuations, is key to understanding their respective
dynamics and their effect on quantum dot coherence properties. We present a
discriminatory approach to all-optical sensing based on two-color resonance
fluorescence of a quantum dot charged with a single electron. Our measurements
show that local magnetic field fluctuations due to nuclear spins in the absence
of an external magnetic field are described by two correlation times, both in
the microsecond regime. The nuclear spin bath dynamics show a strong dependence
on the strength of resonant probing, with correlation times increasing by a
factor of four as the optical transition is saturated. We interpret the
behavior as motional averaging of both the Knight field of the resident
electron spin and the hyperfine-mediated nuclear spin-spin interaction due to
optically-induced electron spin flips.",1408.6437v2
2015-02-02,Two-axis spin squeezing in two cavities,"Ultracold atoms in an ultrahigh-finesse optical cavity are a powerful
platform to produce spin squeezing since photon of cavity mode can induce
nonlinear spin-spin interaction and thus generate a one-axis twisting
Hamiltonian $H_{\text{OAT}}=qJ_{x}^{2}$, whose corresponding maximal squeezing
factor scales as $N^{-2/3}$, where $N$ is the atomic number. On the contrary,
for the other two-axis twisting Hamiltonian
$H_{\text{TAT}}=q(J_{x}^{2}-J_{y}^{2})$, the maximal squeezing factor scales as
$N^{-1}$, approaching the Heisenberg limit. In this paper, inspired by recent
experiments of cavity-assisted Raman transitions, we propose a scheme, in which
an ensemble of ultracold six-level atoms interacts with two quantized cavity
fields and two pairs of Raman lasers, to realize a tunable two-axis spin
Hamiltonian $%H=q(J_{x}^{2}+\chi J_{y}^{2})+\omega_{0}J_{z}$. For proper
parameters, the above one- and two- axis twisting Hamiltonians are recovered,
and the scaling of $N^{-1}$ of the maximal squeezing factor can occur
naturally. On the other hand, in the two-axis twisting Hamiltonian, spin
squeezing is usually reduced when increasing the effective atomic resonant
frequency $\omega_{0}$. Surprisingly, we find that by combined with the
dimensionless parameter $\chi(>-1)$, the effective atomic resonant frequency
$\omega_{0}$ can enhance spin squeezing largely. These results are benefit for
achieving the required spin squeezing in experiments.",1502.00470v1
2015-05-06,Bipolar polaron pair recombination in P3HT/PCBM solar cells,"The unique properties of organic semiconductors make them versatile base
materials for many applications ranging from light emitting diodes to
transistors. The low spin-orbit coupling typical for carbon-based materials and
the resulting long spin lifetimes give rise to a large influence of the
electron spin on charge transport which can be exploited in spintronic devices
or to improve solar cell efficiencies. Magnetic resonance techniques are
particularly helpful to elucidate the microscopic structure of paramagnetic
states in semiconductors as well as the transport processes they are involved
in. However, in organic devices the nature of the dominant spin-dependent
processes is still subject to considerable debate. Using multi-frequency pulsed
electrically detected magnetic resonance (pEDMR), we show that the
spin-dependent response of P3HT/PCBM solar cells at low temperatures is
governed by bipolar polaron pair recombination involving the positive and
negative polarons in P3HT and PCBM, respectively, thus excluding a unipolar
bipolaron formation as the main contribution to the spin-dependent charge
transfer in this temperature regime. Moreover the polaron-polaron coupling
strength and the recombination times of polaron pairs with parallel and
antiparallel spins are determined. Our results demonstrate that the pEDMR pulse
sequences recently developed for inorganic semiconductor devices can very
successfully be transferred to the study of spin and charge transport in
organic semiconductors, in particular when the different polarons can be
distinguished spectrally.",1505.01411v1
2016-07-14,Spin dynamics of diamond nitrogen-vacancy centres at the ground state level anti-crossing and all-optical low frequency magnetic field sensing,"We investigate the photo-induced spin dynamics of single nitrogen-vacancy
(NV) centres in diamond near the electronic ground state level anti-crossing
(GSLAC), which occurs at an axial magnetic field around 1024 G. Using optically
detected magnetic resonance spectroscopy, we first find that the electron spin
transition frequency can be tuned down to 100 kHz for the \NV{14} centre, while
for the \NV{15} centre the transition strength vanishes for frequencies below
about 2 MHz owing to the GSLAC level structure. Using optical pulses to prepare
and readout the spin state, we observe coherent spin oscillations at 1024 G for
the \NV{14}, which originate from spin mixing induced by residual transverse
magnetic fields. This effect is responsible for limiting the smallest
observable transition frequency, which can span two orders of magnitude from
100 kHz to tens of MHz depending on the local magnetic noise. A similar feature
is observed for the \NV{15} centre at 1024 G. As an application of these
findings, we demonstrate all-optical detection and spectroscopy of
externally-generated fluctuating magnetic fields at frequencies from 8 MHz down
to 500 kHz, using a \NV{14} centre. Since the Larmor frequency of most nuclear
spin species lies within this frequency range near the GSLAC, these results
pave the way towards all-optical, nanoscale nuclear magnetic resonance
spectroscopy, using longitudinal spin cross-relaxation.",1607.04006v1
2017-08-09,Electrically driven electron spin resonance mediated by spin-valley-orbit coupling in a silicon quantum dot,"The ability to manipulate electron spins with voltage-dependent electric
fields is key to the operation of quantum spintronics devices, such as
spin-based semiconductor qubits. A natural approach to electrical spin control
exploits the spin-orbit coupling (SOC) inherently present in all materials. So
far, this approach could not be applied to electrons in silicon, due to their
extremely weak SOC. Here we report an experimental realization of electrically
driven electron-spin resonance in a silicon-on-insulator (SOI) nanowire quantum
dot device. The underlying driving mechanism results from an interplay between
SOC and the multi-valley structure of the silicon conduction band, which is
enhanced in the investigated nanowire geometry. We present a simple model
capturing the essential physics and use tight-binding simulations for a more
quantitative analysis. We discuss the relevance of our findings to the
development of compact and scalable electron-spin qubits in silicon.",1708.02903v2
2018-05-22,FMR-related phenomena in spintronic devices,"Spintronic devices, such as non-volatile magnetic random access memories and
logic devices, have attracted considerable attention as potential candidates
for future high efficient data storage and computing technology. In a heavy
metal or other emerging material with strong spin-orbit coupling (SOC), the
charge currents induce spin currents or spin accumulations via SOC. The
generated spin currents can exert spin-orbit torques (SOTs) on an adjacent
ferromagnet, which opens up a new way to realize magnetization dynamics and
switching of the ferromagnetic layer for spintronic devices. In the SOT scheme,
the charge-to-spin interconversion efficiency (SOT efficiency) is an important
figure of merit for applications. For the effective characterization of this
efficiency, the ferromagnetic resonance (FMR) based methods, such as the spin
transfer torque ferromagnetic resonance (ST-FMR) and the spin pumping, are
common utilized in addition to low frequency harmonic or dc measurements. In
this review, we focus on the ST-FMR measurements for the evaluation of the SOT
efficiency. We provide a brief summary of the different ST-FMR setups and data
analysis methods. We then discuss ST-FMR and SOT studies in various materials,
including heavy metals and alloys, topological insulators, two dimensional (2D)
materials, interfaces with strong Rashba effect, antiferromagnetic materials,
two dimensional electron gas (2DEG) in oxide materials and oxidized nonmagnetic
materials.",1805.08496v1
2014-06-02,Knight shift and nuclear spin relaxation in Fe/n-GaAs heterostructures,"We investigate the dynamically polarized nuclear-spin system in
Fe/\emph{n}-GaAs heterostructures using the response of the electron-spin
system to nuclear magnetic resonance (NMR) in lateral spin-valve devices. The
hyperfine interaction is known to act more strongly on donor-bound electron
states than on those in the conduction band. We provide a quantitative model of
the temperature dependence of the occupation of donor sites. With this model we
calculate the ratios of the hyperfine and quadrupolar nuclear relaxation rates
of each isotope. For all temperatures measured, quadrupolar relaxation limits
the spatial extent of nuclear spin-polarization to within a Bohr radius of the
donor sites and is directly responsible for the isotope dependence of the
measured NMR signal amplitude. The hyperfine interaction is also responsible
for the $2\text{ kHz}$ Knight shift of the nuclear resonance frequency that is
measured as a function of the electron spin accumulation. The Knight shift is
shown to provide a measurement of the electron spin-polarization that agrees
qualitatively with standard spin transport measurements.",1406.0436v2
2019-02-04,Electron Spin Resonance of P Donors in Isotopically Purified Si Detected by Contactless Photoconductivity,"Coherence times of electron spins bound to phosphorus donors have been
measured, using a standard Hahn echo technique, to be up to 20 ms in
isotopically pure silicon with [P]$ = 10^{14}$ cm$^{-3}$ and at temperatures
$\leq 4 $K. Although such times are exceptionally long for electron spins in
the solid state, they are nevertheless limited by donor electron spin-spin
interactions. Suppressing such interactions requires even lower donor
concentrations, which lie below the detection limit for typical electron spin
resonance (ESR) spectrometers. Here we describe an alternative method for
phosphorus donor ESR detection, exploiting the spin-to-charge conversion
provided by the optical donor bound exciton transition. We characterise the
method and its dependence on laser power and use it to measure a coherence time
of $T_2 = 130 $ms for one of the purest silicon samples grown to-date ([P]$ =
5\times 10^{11} $cm$^{-3}$). We then benchmark this result using an alternative
application of the donor bound exciton transition: optically polarising the
donor spins before using conventional ESR detection at 1.7~K for a sample with
[P]$ = 4\times10^{12} $cm$^{-3}$, and measuring in this case a $T_2$ of 350 ms.",1902.01343v3
2019-06-10,Room Temperature Initialisation and Readout of Intrinsic Spin Defects in a Van der Waals Crystal,"Optically addressable spins in widebandgap semiconductors have become one of
the most prominent platforms for exploring fundamental quantum phenomena. While
several candidates in 3D crystals including diamond and silicon carbide have
been extensively studied, the identification of spindependent processes in
atomically thin 2D materials has remained elusive. Although optically
accessible spin states in hBN are theoretically predicted, they have not yet
been observed experimentally. Here, employing rigorous electron paramagnetic
resonance techniques and photoluminescence spectroscopy, we identify
fluorescence lines in hexagonal boron nitride associated with a particular
defect, the negatively charged boron vacancy and determine the parameters of
its spin Hamiltonian. We show that the defect has a triplet ground state with a
zero field splitting of 3.5 GHz and establish that the centre exhibits
optically detected magnetic resonance at room temperature. We also demonstrate
the spin polarization of this centre under optical pumping, which leads to
optically induced population inversion of the spin ground state a prerequisite
for coherent spin manipulation schemes. Our results constitute a leap forward
in establishing two dimensional hBN as a prime platform for scalable quantum
technologies, with extended potential for spin based quantum information and
sensing applications, as our ODMR studies on hBN NV diamonds hybrid structures
show.",1906.03774v1
2017-06-25,Robust electric dipole transition at microwave frequencies for nuclear spin qubits in silicon,"The nuclear spin state of a phosphorus donor ($^{31}$P) in isotopically
enriched silicon-28 is an excellent host to store quantum information in the
solid state. The spin's insensitivity to electric fields yields a solid-state
qubit with record coherence times, but also renders coupling to other quantum
systems very challenging. Here, we describe how to generate a strong electric
dipole ($>100$ Debye) at microwave frequencies for the nuclear spin. This is
achieved by applying a magnetic drive to the spin of the donor-bound electron,
while simultaneously controlling its charge state with electric fields. Under
certain conditions, the microwave magnetic drive also renders the nuclear spin
resonance frequency and electric dipole strongly insensitive to electrical
noise, yielding long ($>1$ ms) dephasing times and robust gate operations. The
nuclear spin could then be strongly coupled to microwave resonators, with a
vacuum Rabi splitting of order 1 MHz, or to other nuclear spins, nearly half a
micrometer apart, via strong electric dipole-dipole interaction. This work
brings the $^{31}$P nuclear qubit into the realm of hybrid quantum systems and
opens up new avenues in quantum information processing.",1706.08095v2
2019-03-07,Readout of a dopant spin in the anisotropic quantum dot with a single magnetic ion,"Owing to exchange interaction between the exciton and magnetic ion, a quantum
dot embedding a single magnetic ion is a great platform for optical control of
individual spin. In particular, a quantum dot provides strong and sharp optical
transitions, which give experimental access to spin states of an individual
magnetic ion. We show, however, that physics of quantum dot excitons also
complicate spin readout and optical spin manipulation in such a system. This is
due to electron-hole exchange interaction in anisotropic quantum dots, which
affects the polarization of the emission lines. One of the consequences is that
the intensity of spectral lines in a single spectrum are not simply
proportional to the population of various spin states of magnetic ion. In order
to provide a solution of the above problem, we present a method of extracting
both the spin polarisation degree of a neutral exciton and magnetic dopant
inside a semiconductor quantum dot in an external magnetic field. Our approach
is experimentally verified on a system of CdSe/ZnSe quantum dot containing a
single Fe$^{2+}$ ion. Both the resonant and non-resonant excitation regimes are
explored resulting in a record high optical orientation efficiency of dopant
spin in the former case. The proposed solutions can be easily expanded to any
other system of quantum dots containing magnetic dopants.",1903.02969v1
2019-05-31,Fingerprints of Kitaev physics in the magnetic excitations of honeycomb iridates,"In the quest for realizations of quantum spin liquids, the exploration of
Kitaev materials - spin-orbit entangled Mott insulators with strong
bond-directional exchanges - has taken center stage. However, in these
materials the local spin-orbital j=1/2 moments typically show long-range
magnetic order at low temperature, thus defying the formation of a spin-liquid
ground state. Using resonant inelastic x-ray scattering (RIXS), we here report
on a proximate spin liquid regime with clear fingerprints of Kitaev physics in
the magnetic excitations of the honeycomb iridates alpha-Li2IrO3 and Na2IrO3.
We observe a broad continuum of magnetic excitations that persists up to at
least 300K, more than an order of magnitude larger than the magnetic ordering
temperatures. We prove the magnetic character of this continuum by an analysis
of the resonance behavior. RIXS measurements of the dynamical structure factor
for energies within the continuum show that dynamical spin-spin correlations
are restricted to nearest neighbors. Notably, these spectroscopic observations
are also present in the magnetically ordered state for excitation energies
above the conventional magnon excitations. Phenomenologically, our data agree
with inelastic neutron scattering results on the related honeycomb compound
RuCl3, establishing a common ground for a proximate Kitaev spin-liquid regime
in these materials.",1905.13590v1
2020-03-02,Cavity quantum electrodynamic readout of a solid-state spin sensor,"Robust, high-fidelity readout is central to quantum device performance.
Overcoming poor readout is an increasingly urgent challenge for devices based
on solid-state spin defects, particularly given their rapid adoption in quantum
sensing, quantum information, and tests of fundamental physics. Spin defects in
solids combine the repeatability and precision available to atomic and
cryogenic systems with substantial advantages in compactness and range of
operating conditions. However, in spite of experimental progress in specific
systems, solid-state spin sensors still lack a universal, high-fidelity readout
technique. Here we demonstrate high-fidelity, room-temperature readout of an
ensemble of nitrogen-vacancy (NV) centers via strong coupling to a dielectric
microwave cavity, building on similar techniques commonly applied in cryogenic
circuit cavity quantum electrodynamics. This strong collective interaction
allows the spin ensemble's microwave transition to be probed directly, thereby
overcoming the optical photon shot noise limitations of conventional
fluorescence readout. Applying this technique to magnetometry, we show magnetic
sensitivity approaching the Johnson-Nyquist noise limit of the system. This
readout technique is viable for the many paramagnetic spin systems that exhibit
resonances in the microwave domain. Our results pave a clear path to achieve
unity readout fidelity of solid-state spin sensors through increased ensemble
size, reduced spin-resonance linewidth, or improved cavity quality factor.",2003.01104v1
2021-02-17,Optically reconfigurable quantum spin-valley Hall effect of light in coupled nonlinear ring resonator lattice,"Scattering immune propagation of light in topological photonic systems may
revolutionarize the design of integrated photonic circuits for information
processing and communications. In optics, various photonic topological circuits
have been developed, which were based on classical emulation of either quantum
spin Hall effect or quantum valley Hall effect. On the other hand, the
combination of both the valley and spin degrees of freedom can lead to a new
kind of topological transport phenomenon, dubbed quantum spin valley Hall
effect (QSVH), which can further expand the number of topologically protected
edge channels and would be useful for information multiplexing. However, it is
challenging to realize QSVH in most known material platforms, due to the
requirement of breaking both the (pseudo-)fermionic time-reversal (T) and
parity symmetries (P) individually, but leaving the combined symmetry S=TP
intact. Here, we propose an experimentally feasible platform to realize QSVH
for light, based on coupled ring resonators mediated by optical Kerr
nonlinearity. Thanks to the inherent flexibility of cross-mode modulation
(XMM), the coupling between the probe light can be engineered in a controllable
way such that spin-dependent staggered sublattice potential emerges in the
effective Hamiltonian. With delicate yet experimentally feasible pump
conditions, we show the existence of spin valley Hall induced topological edge
states. We further demonstrate that both degrees of freedom, i.e., spin and
valley, can be manipulated simultaneously in a reconfigurable manner to realize
spin-valley photonics, doubling the degrees of freedom for enhancing the
information capacity in optical communication systems.",2102.08750v1
2016-11-23,X-ray imaging of spin currents and magnetisation dynamics at the nanoscale,"Understanding how spins move in time and space is the aim of both fundamental
and applied research in modern magnetism. Over the past three decades, research
in this field has led to technological advances that have had a major impact on
our society, while improving the understanding of the fundamentals of spin
physics. However, important questions still remain unanswered, because it is
experimentally challenging to directly observe spins and their motion with a
combined high spatial and temporal resolution. In this article, we present an
overview of the recent advances in X-ray microscopy that allow researchers to
directly watch spins move in time and space at the microscopically relevant
scales. We discuss scanning X-ray transmission microscopy (STXM) at resonant
soft X-ray edges, which is available at most modern synchrotron light sources.
This technique measures magnetic contrast through the X-ray magnetic circular
dichroism (XMCD) effect at the resonant absorption edges, while focusing the
X-ray radiation at the nanometre scale, and using the intrinsic pulsed
structure of synchrotron-generated X-rays to create time-resolved images of
magnetism at the nanoscale. In particular, we discuss how the presence of spin
currents can be detected by imaging spin accumulation, and how the
magnetisation dynamics in thin ferromagnetic films can be directly imaged. We
discuss how a direct look at the phenomena allows for a deeper understanding of
the the physics at play, that is not accessible to other, more indirect
techniques. Finally, we present an overview of the exciting opportunities that
lie ahead to further understand the fundamentals of novel spin physics,
opportunities offered by the appearance of diffraction limited storage rings
and free electron lasers.",1611.07691v2
2022-06-08,Coherent spin dynamics of rare-earth doped crystals in the high-cooperativity regime,"Rare-earth doped crystals have long coherence times and the potential to
provide quantum interfaces between microwave and optical photons. Such
applications benefit from a high cooperativity between the spin ensemble and a
microwave cavity -- this motivates an increase in the rare earth ion
concentration which in turn impacts the spin coherence lifetime. We measure
spin dynamics of two rare-earth spin species, $^{145}$Nd and Yb doped into
Y$_{2}$SiO$_{5}$, coupled to a planar microwave resonator in the high
cooperativity regime, in the temperature range 1.2 K to 14 mK. We identify
relevant decoherence mechanisms including instantaneous diffusion arising from
resonant spins and temperature-dependent spectral diffusion from impurity
electron and nuclear spins in the environment. We explore two methods to
mitigate the effects of spectral diffusion in the Yb system in the
low-temperature limit, first, using magnetic fields of up to 1 T to suppress
impurity spin dynamics and, second, using transitions with low effective
g-factors to reduce sensitivity to such dynamics. Finally, we demonstrate how
the `clock transition' present in the $^{171}$Yb system at zero field can be
used to increase coherence times up to $T_{2} = 6(1)$ ms.",2206.04027v2
2022-06-28,Strong coupling between a photon and a hole spin in silicon,"Spins in semiconductor quantum dots constitute a promising platform for
scalable quantum information processing. Coupling them strongly to the photonic
modes of superconducting microwave resonators would enable fast non-demolition
readout and long-range, on-chip connectivity, well beyond nearest-neighbor
quantum interactions. Here we demonstrate strong coupling between a microwave
photon in a superconducting resonator and a hole spin in a silicon-based double
quantum dot issued from a foundry-compatible MOS fabrication process. By
leveraging the strong spin-orbit interaction intrinsically present in the
valence band of silicon, we achieve a spin-photon coupling rate as high as
330~MHz largely exceeding the combined spin-photon decoherence rate. This
result, together with the recently demonstrated long coherence of hole spins in
silicon, opens a new realistic pathway to the development of circuit quantum
electrodynamics with spins in semiconductor quantum dots.",2206.14082v2
2022-09-06,Temperature- and field angular-dependent helical spin period characterized by magnetic dynamics in a chiral helimagnet $MnNb_3S_6$,"The chiral magnets with topological spin textures provide a rare platform to
explore topology and magnetism for potential application implementation. Here,
we study the magnetic dynamics of several spin configurations on the monoaxial
chiral magnetic crystal $MnNb_3S_6$ via broadband ferromagnetic resonance (FMR)
technique at cryogenic temperature. In the high-field forced ferromagnetic
state (FFM) regime, the obtained frequency f vs. resonance field Hres
dispersion curve follows the well-known Kittel formula for a single FFM, while
in the low-field chiral magnetic soliton lattice (CSL) regime, the dependence
of Hres on magnetic field angle can be well-described by our modified Kittel
formula including the mixture of a helical spin segment and the FFM phase.
Furthermore, compared to the sophisticated Lorentz micrograph technique, the
observed magnetic dynamics corresponding to different spin configurations allow
us to obtain temperature- and field-dependent proportion of helical spin
texture and helical spin period ratio L(H)/L(0) via our modified Kittel
formula. Our results demonstrated that field- and temperature-dependent
nontrivial magnetic structures and corresponding distinct spin dynamics in
chiral magnets can be an alternative and efficient approach to uncovering and
controlling nontrivial topological magnetic dynamics.",2209.02266v1
2022-11-07,Room temperature charge-to-spin conversion from q-2DEG at SrTiO3-based interfaces,"Interfacial two-dimensional electron gas (2DEG), especially the SrTiO3-based
ones at the unexpected interface of insulators, have emerged to be a promising
candidate for efficient charge-spin current interconversion. In this article,
to gain insight into the mechanism of the charge-spin current interconversion
at the oxide-based 2DEG, we focused on conducting interfaces between insulating
SrTiO3 and two types of aluminium-based amorphous insulators, namely SrTiO3/AlN
and SrTiO3/Al2O3, and estimated their charge-spin conversion efficiency,
{\theta}_cs. The two types of amorphous insulators were selected to explicitly
probe the overlooked contribution of oxygen vacancy to the {\theta}_cs. We
proposed a mechanism to explain results of spin-torque ferromagnetic resonance
(ST-FMR) measurements and developed an analysis protocol to reliably estimate
the {\theta}_cs of the oxide based 2DEG. The resultant {\theta}_cs/t, where t
is the thickness of the 2DEG, were estimated to be 0.244 nm-1 and 0.101 nm-1
for the SrTiO3/AlN and SrTiO3/Al2O3, respectively, and they are strikingly
comparable to their crystalline counterparts. Furthermore, we also observe a
large direct current modulation of resonance linewidth in SrTiO3/AlN samples,
confirming its high {\theta}_cs and attesting an oxygen-vacancy-enabled
charge-spin conversion. Our findings emphasize the defects' contribution to the
charge-spin interconversion, especially in the oxide-based low dimensional
systems, and provide a way to create and enhance charge-spin interconversion
via defect engineering.",2211.03383v1
2023-01-27,Realization of valley-spin polarized current via parametric pump in monolayer $\rm MoS_2$,"Monolayer $MoS_2$ is a typical valleytronic material with valley-spin locked
valence bands. We numerically investigate the valley-spin polarized current in
monolayer $\rm MoS_2$ via adiabatic electron pumping. By introducing an
exchange field to break the energy degeneracy of monolayer $MoS_2$, the top of
its valence bands is valley-spin polarized and tunable by the exchange field. A
device with spin-up polarized left lead, spin-down polarized right lead, and
untuned central region is constructed through applying different exchange
fields in the corresponding regions. Then, equal amount of pumped currents with
opposite valley-spin polarization are simultaneously generated in the left and
right leads when periodically varying two pumping potentials. Numerical results
show that the phase difference between the pumping potentials can change the
direction and hence polarization of the pumped currents. It is found that the
pumped current exhibits resonant behavior in the valley-spin locked energy
window, which depends strongly on the system size and is enhanced to resonant
current peaks at certain system lengths. More importantly, the pumped current
periodically oscillates as a function of the system length, which is closely
related to the oscillation of transmission. The effects of other system
parameters, such as the pumping amplitude and the static potential, are also
thoroughly discussed.",2301.11644v1
2023-04-25,Spin-liquid-like state in a square lattice antiferromagnet,"Collective behavior of spins, frustration-induced strong quantum fluctuations
and subtle interplay between competing degrees of freedom in quantum materials
can lead to correlated quantum states with fractional excitations that are
essential ingredients for establishing paradigmatic models and have immense
potential for quantum technologies. Quenched randomness is a new paradigm in
elucidating the emergence of spin-liquidlike states in geometrically frustrated
magnets. Herein, we report magnetization, specific heat, electron spin
resonance, and muon spin resonance studies on a 3d-electron-based square
lattice antiferromagnet Sr3CuTa2O9. In this material, S = 1/2 Cu2+
nearest-neighbor ions constitute a two-dimensional square lattice. The negative
value of Curie-Weiss temperature, obtained from the Curie-Weiss fit of
high-temperature magnetic susceptibility data indicates the presence of
antiferromagnetic interaction between Cu2+ moments. Specific heat data show the
absence of long-range magnetic ordering down to 64 mK despite a reasonably
strong exchange interaction between Cu2+ spins as reflected from a Curie-Weiss
temperature of -27 K. The power-law behavior and the data collapse of specific
heat and magnetization data evince the emergence of a random-singlet state in
Sr3CuTa2O9. The power-law-like spin auto-correlation function and the data
collapse of muon polarization asymmetry with longitudinal field dependence of
t/({\mu}0H){\gamma} further support credence to the presence of a
randomness-induced liquid-like state. Our results suggest that randomness
induced by disorder is a viable route to realize quantum spin liquid-like state
in this square lattice antiferromagnet.",2304.13116v1
2007-11-02,Electric-field controlled spin reversal in a quantum dot with ferromagnetic contacts,"Manipulation of the spin-states of a quantum dot by purely electrical means
is a highly desirable property of fundamental importance for the development of
spintronic devices such as spin-filters, spin-transistors and single-spin
memory as well as for solid-state qubits. An electrically gated quantum dot in
the Coulomb blockade regime can be tuned to hold a single unpaired spin-1/2,
which is routinely spin-polarized by an applied magnetic field. Using
ferromagnetic electrodes, however, the properties of the quantum dot become
directly spin-dependent and it has been demonstrated that the ferromagnetic
electrodes induce a local exchange-field which polarizes the localized spin in
the absence of any external fields. Here we report on the experimental
realization of this tunneling-induced spin-splitting in a carbon nanotube
quantum dot coupled to ferromagnetic nickel-electrodes. We study the
intermediate coupling regime in which single-electron states remain well
defined, but with sufficiently good tunnel-contacts to give rise to a sizable
exchange-field. Since charge transport in this regime is dominated by the
Kondo-effect, we can utilize this sharp many-body resonance to read off the
local spin-polarization from the measured bias-spectroscopy. We show that the
exchange-field can be compensated by an external magnetic field, thus restoring
a zero-bias Kondo-resonance, and we demonstrate that the exchange-field itself,
and hence the local spin-polarization, can be tuned and reversed merely by
tuning the gate-voltage. This demonstrates a very direct electrical control
over the spin-state of a quantum dot which, in contrast to an applied magnetic
field, allows for rapid spin-reversal with a very localized addressing.",0711.0320v1
2017-02-01,Coherent Rabi dynamics of a superradiant spin ensemble in a microwave cavity,"We achieve the strong coupling regime between an ensemble of phosphorus donor
spins in a highly enriched $^{28}$Si crystal and a 3D dielectric resonator.
Spins were polarized beyond Boltzmann equilibrium using spin selective optical
excitation of the no-phonon bound exciton transition resulting in $N$ =
$3.6\cdot10^{13}$ unpaired spins in the ensemble. We observed a normal mode
splitting of the spin ensemble-cavity polariton resonances of 2$g\sqrt{N}$ =
580 kHz (where each spin is coupled with strength $g$) in a cavity with a
quality factor of 75,000 ($\gamma \ll \kappa \approx$ 60 kHz where $\gamma$ and
$\kappa$ are the spin dephasing and cavity loss rates, respectively). The spin
ensemble has a long dephasing time (T$_2^*$ = 9 $\mu$s) providing a wide window
for viewing the dynamics of the coupled spin ensemble-cavity system. The free
induction decay shows up to a dozen collapses and revivals revealing a coherent
exchange of excitations between the superradiant state of the spin ensemble and
the cavity at the rate $g\sqrt{N}$. The ensemble is found to evolve as a single
large pseudospin according to the Tavis-Cummings model due to minimal
inhomogeneous broadening and uniform spin-cavity coupling. We demonstrate
independent control of the total spin and the initial Z-projection of the
psuedospin using optical excitation and microwave manipulation respectively. We
vary the microwave excitation power to rotate the pseudospin on the Bloch
sphere and observe a long delay in the onset of the superradiant emission as
the pseudospin approaches full inversion. This delay is accompanied by an
abrupt $\pi$ phase shift in the peusdospin microwave emission. The scaling of
this delay with the initial angle and the sudden phase shift are explained by
the Tavis-Cummings model.",1702.00504v1
2006-10-17,QPOs in microquasars: the spin problem,"In the Galactic microquasars with double peak kHz quasi-periodic oscillations
(QPOs), the ratio of the two frequencies is 3:2. This supports the suggestion
that double peak kHz QPOs are due to a non-linear resonance between two modes
of accretion disk oscillations. For the microquasars with known mass, we
briefly compare the black hole spin estimates based on the orbital resonance
model with the recently reported spin predictions obtained by fitting the
spectral continua. Results of these two approaches are not in good agreement.
We stress that if the spectral fit estimates are accurate and can be taken as
referential (which is still questionable), the disagreement between the
predicted and referential values would represent a rather generic problem for
any relativistic QPO model, as no spin influence would appear in the observed
1/M scaling of the QPO frequencies. The epicyclic frequencies relevant in these
models are often considered to be equal to those of a test particle motion.
However modifications of the frequencies due to the disc pressure or other
non-geodesic effects may play an important role, and the inaccuracy introduced
in the spin estimates by the test particle approximation could be crucial.",0610497v1
1999-07-13,Nonlinear Spin Dynamics in Ferromagnets with Electron-Nuclear Coupling,"Nonlinear spin motion in ferromagnets is considered with nonlinearity due to
three factors: (i) the sample is prepared in a strongly nonequilibrium state,
so that evolution equations cannot be linearized as would be admissible for
spin motion not too far from equilibrium, (ii) the system considered consists
of interacting electron and nuclear spins coupled with each other via hyperfine
forces, and (iii) the sample is inserted into a coil of a resonant electric
circuit producing a resonator feedback field. Due to these nonlinearities,
coherent motion of spins can develop, resulting in their ultrafast relaxation.
A complete analysis of mechanisms triggering such a coherent motion is
presented. This type of ultrafast coherent relaxation can be used for studying
intrinsic properties of magnetic materials.",9907188v1
2001-07-17,Cu Nuclear Quadrupole Resonance Study of the Spin-Peierls Compound Cu1-xMgxGeO3: A Possibility of Precursory Dimerization,"We report on a zero-field 63Cu nuclear quadrupole resonance (NQR) study of
nonmagnetic Mg impurity substituted Cu1-xMgxGeO3 (single crystals; the
spin-Peierls transition temperature Tsp~14, 13.5, and 11 K for x=0, 0.0043, and
0.020) in a temperature range from 4.2 K to 250 K. We found that below T*~77 K,
Cu NQR spectra are broadened and nonexponential Cu nuclear spin-lattice
relaxation increases for undoped and more remarkably for Mg-doped samples. The
results indicate that random lattice distortion and impurity-induced spins
appear below T*, which we associate with a precursor of the spin-Peierls
transition. Conventional magnetic critical slowing down does not appear down to
4.2 K below Tsp.",0107353v1
2001-12-07,Time Scales of Phonon Induced Decoherence of Semiconductor Spin Qubits,"Decoherence of a shallow donor electron spin in silicon caused by
electron-lattice interaction is studied. We find that there are two time scales
associated with the evolution of the electron spin density matrix: the fast but
incomplete decay due to the interaction with non-resonant phonons followed by
slow relaxation resulting from spin flips accompanied by resonant phonon
emission. We estimate both time scales as well as the magnitude of the initial
drop of coherence for P donor in Si and argue that the approach used is
suitable for evaluation of phonon induced decoherence for a general class of
localized spin states in semiconductors.",0112135v1
2002-06-12,Spin-spin cross-relaxation in single-molecule magnets,"It is shown that dipolar and weak superexchange interactions between the spin
systems of single-molecule magnets (SMM) play an important role in the
relaxation of magnetization. These interactions can reduce or increase resonant
tunneling. The one-body tunnel picture of SMMs is not always sufficient to
explain the measured tunnel transitions. We propose to improve the picture by
including also two-body tunnel transitions such as spin-spin cross-relaxation
(SSCR). A Mn4 SMM is used as a model system to study the SSCR which plays also
an important role for other SMMs like Mn12 or Fe8. At certain external fields,
SSCRs can lead to quantum resonances which can show up in hysteresis loop
measurements as well defined steps. A simple model allows us to explain
quantitatively all observed transitions. Including three-body transitions or
dealing with the many-body problem is beyond the slope of this paper.",0206195v1
2003-05-14,Orbital order in the low-dimensional quantum spin system TiOCl probed by ESR,"We present electron spin resonance data of Ti$^{3+}$ (3$d^1$) ions in single
crystals of the novel layered quantum spin magnet TiOCl. The analysis of the g
tensor yields direct evidence that the d_{xy} orbital from the t_{2g} set is
predominantly occupied and owing to the occurrence of orbital order a linear
spin chain forms along the crystallographic b axis. This result corroborates
recent theoretical LDA+U calculations of the band structure. The temperature
dependence of the parameters of the resonance signal suggests a strong coupling
between spin and lattice degrees of freedom and gives evidence for a transition
to a nonmagnetic ground state at 67 K.",0305317v2
2003-07-28,Optical Detection of Single-Electron Spin Decoherence in a Quantum Dot,"We propose a method based on optically detected magnetic resonance (ODMR) to
measure the decoherence time $T_{2}$ of a single electron spin in a
semiconductor quantum dot. The electron spin resonance (ESR) of a single excess
electron on a quantum dot is probed by circularly polarized laser excitation.
Due to Pauli blocking, optical excitation is only possible for one of the
electron-spin states. The photoluminescence is modulated due to the ESR which
enables the measurement of electron spin decoherence. We study different
possible schemes for such an ODMR setup.",0307669v2
2003-09-19,Quantum Dissipative Dynamics of the Magnetic Resonance Force Microscope in the Single-Spin Detection Limit,"We study a model of a magnetic resonance force microscope (MRFM) based on the
cyclic adiabatic inversion technique as a high-resolution tool to detect single
electron spins. We investigate the quantum dynamics of spin and cantilever in
the presence of coupling to an environment. To obtain the reduced dynamics of
the combined system of spin and cantilever, we use the Feynman-Vernon influence
functional and get results valid at any temperature as well as at arbitrary
system-bath coupling strength. We propose that the MRFM can be used as a
quantum measurement device, i.e., not only to detect the modulus of the spin
but also its direction.",0309456v1
2004-09-10,A study of the deep structure of the energy landscape of glassy polystyrene: the exponential distribution of the energy-barriers revealed by high-field Electron Spin Resonance spectroscopy,"The reorientation of one small paramagnetic molecule (spin probe) in glassy
polystyrene (PS) is studied by high-field Electron Spin Resonance spectroscopy
at two different Larmor frequencies (190 and 285 GHz). The exponential
distribution of the energy-barriers for the rotational motion of the spin probe
is unambigously evidenced at both 240K and 270K. The same shape for the
distribution of the energy-barriers of PS was evidenced by the master curves
provided by previous mechanical and light scattering studies. The breadth of
the energy-barriers distribution of the spin probe is in the range of the
estimates of the breadth of the PS energy-barriers distribution. The evidence
that the deep structure of the energy landscape of PS exhibits the exponential
shape of the energy-barriers distribution agrees with results from
extreme-value statistics and the trap model by Bouchaud and coworkers.",0409258v2
2004-11-10,Dynamical nuclear polarization and nuclear magnetic fields in semiconductor nanostructures,"We investigate the dynamic nuclear polarization from the hyperfine
interaction between nonequilibrium electronic spins and nuclear spins coupled
to them in semiconductor nanostructures. We derive the time and position
dependence of the induced nuclear spin polarization and dipolar magnetic
fields. In GaAs/AlGaAs parabolic quantum wells the nuclear spin polarization
can be as high as 80% and the induced nuclear magnetic fields can approach a
few gauss with an associated nuclear resonance shift of the order of kHz when
the electronic system is 100% spin polarized. These fields and shifts can be
tuned using small electric fields. We discuss the implications of such control
for optical nuclear magnetic resonance experiments in low-dimensional
semiconductor nanostructures.",0411277v1
2004-11-24,Spin-charge mixing effects on resonant tunneling in a polarized Luttinger Liquid,"We investigate spin-charge mixing effect on resonant tunneling in
spin-polarized Tomonaga-Luttinger liquid with double impurities. The mixing
arises from Fermi velocity difference between two spin species due to Zeeman
effect. Zero bias conductance is calculated as a function of gate voltage
$V_{\rm g}$, gate magnetic field $B_{\rm g}$, temperature and magnetic field
applied to the system. Mixing effect is shown to cause rotation of the lattice
pattern of the conductance peaks in $(V_{\rm g},B_{\rm g})$ plane, which can be
observed in experiments. At low temperatures, the contour shapes are classified
into three types, reflecting the fact that effective barrier potential is
renormalized towards ``perfect reflection'', ``perfect transmission'' and
magnetic field induced ``spin-filtering'', respectively.",0411600v3
2005-12-02,Electrically detected electron spin resonance in a high mobility silicon quantum well,"The resistivity change due to electron spin resonance (ESR) absorption is
investigated in a high-mobility two-dimensional electron system formed in a
Si/SiGe heterostructure. Results for a specific Landau level configuration
demonstrate that the primary cause of the ESR signal is a reduction of the spin
polarization, not the effect of electron heating. The longitudinal spin
relaxation time T_1 is obtained to be of the order of 1 ms in an in-plane
magnetic field of 3.55 T. The suppression of the effect of the Rashba fields
due to high-frequency spin precession explains the very long T_1.",0512041v4
2006-02-06,Switching the sign of photon induced exchange interactions in semiconductor microcavities with finite quality factors,"We investigate coupling of localized spins in a semiconductor quantum dot
embedded in a microcavity with a finite quality factor. The lowest cavity mode
and the quantum dot exciton are coupled forming a polariton, whereas excitons
interact with localized spins via exchange. The finite quality of the cavity Q
is incorporated in the model Hamiltonian by adding an imaginary part to the
photon frequency. The Hamiltonian, which treats photons, spins and excitons
quantum mechanically, is solved exactly. Results for a single polariton clearly
demonstrate the existence of a resonance, sharper as the temperature decreases,
that shows up as an abrupt change between ferromagnetic and antiferromagnetic
indirect anisotropic exchange interaction between localized spins. The origin
of this spin-switching finite-quality-factor effect is discussed in detail
remarking on its dependence on model parameters, i.e., light-matter coupling,
exchange interaction between impurities, detuning and quality factor. For
parameters corresponding to the case of a (Cd,Mn)Te quantum dot, the resonance
shows up for Q around 70 and detuning around 10 meV. In addition, we show that,
for such a quantum dot, and the best cavities actually available (quality
factors better than 200) the exchange interaction is scarcely affected.",0602122v1
2006-02-10,Theory of Electric Dipole Spin Resonance in a Parabolic Quantum Well,"A theory of Electric Dipole Spin Resonance (EDSR), that is caused by various
mechanisms of spin-orbit coupling, is developed as applied to free electrons in
a parabolic quantum well. Choosing a parabolic shape of the well has allowed us
to find explicit expressions for the EDSR intensity and its dependence on the
magnetic field direction in terms of the basic parameters of the Hamiltonian.
By using these expressions, we have investigated and compared the effect of
specific mechanisms of spin orbit (SO) coupling and different polarizations of
ac electric field on the intensity of EDSR. Angular dependences of the EDSR
intensity are indicative of the relative contributions of the competing
mechanisms of SO coupling. Our results show that electrical manipulating
electron spins in quantum wells is generally highly efficient, especially by an
in-plane ac electric field.",0602264v1
2006-05-12,Comment on Frequency response and origin of the spin-1/2 photolumines-cence-detected magnetic resonance in a pi-conjugated polymer,"In a recent paper Segal et al. [1] attempted to explain the dynamics of spin
1/2 photoluminescence detected magnetic resonance (PLDMR) in films of a
pi-conjugated polymer, namely a soluble de-rivative of poly(phenylene-vinylene)
[MEH-PPV] using a model (dubbed TPQ), in which the PLDMR is due to spin
dependent triplet-polaron interactions that reduce the polarons density and
consequent quenching of singlet excitons. We studied the full PLDMR and
photoinduced ab-sorption (PA) dynamics of MEH-PPV films as a function of
microwave power at various tempera-tures. We show, firstly, that the TPQ model
is incompatible with the full frequency dependent spin 1/2 PLDMR response;
secondly, it is not in agreement with the spin-1 PLDMR temperature dependence;
thirdly, it predicts a much shorter triplet exciton lifetime than that obtained
experimentally; and fourthly, that is in contradiction with the temperature
dependencies of spin 1/2 PLDMR and triplet exciton PA. In contrast, an
alternative model, namely the spin dependent re-combination of polarons, is
capable of explaining the whole body of experimental results, and in particular
the PLDMR dynamics.",0605322v1
2006-09-01,Spin dynamics of $Yb Rh_2 Si_2$ observed by Electron Spin Resonance,"Below the Kondo temperature $T_{\rm K}$ electron spin resonance (ESR) usually
is not observable from the Kondo-ion itself because the characteristic spin
fluctuation energy results in a huge width of the ESR line. The heavy fermion
metal YbRh$_{2}$Si$_{2}$ seems to be an exceptional case where definite ESR
spectra show characteristic properties of the Kondo-ion Yb$^{3+}$ well
\textit{below} $T_{\rm K}$. We found that the spin dynamics of
YbRh$_{2}$Si$_{2}$, as determined by its ESR relaxation, is spatially
characterized by an anisotropy of the zero temperature residual relaxation
only.",0609020v1
2006-09-11,"Current-driven ferromagnetic resonance, mechanical torques and rotary motion in magnetic nanostructures","We study theoretically the detection and possible utilization of electric
current-induced mechanical torques in ferromagnetic-normal metal
heterostructures that are generated by spin-flip scattering or the absorption
of transverse spin currents by a ferromagnet. To this end, we analyze the DC
voltage signals over a spin valve that is driven by an AC current. In agreement
with recent studies, this ""rectification"", measured as a function of AC
frequency and applied magnetic field, contains important information on the
magnetostatics and --dynamics. Subsequently, we show that the vibrations
excited by spin-transfer to the lattice can be detected as a splitting of the
DC voltage resonance. Finally, we propose a concept for a spin-transfer-driven
electric nanomotor based on integrating metallic nanowires with carbon
nanotubes, in which the current-induced torques generate a rotary motion.",0609258v2
2006-10-31,Resonant magnetoresistance in organic spin-valves,"We investigate theoretically the effects of surface states over the
magnetoresistance of Ni-based organic spin-valves. In particular we perform
{\it ab initio} electronic transport calculations for a benzene-thiolate
molecule chemically attached to a Ni [001] surface and contacted either by Te
to another Ni [001] surface, or terminated by a thiol group and probed by a Ni
STM tip. In the case of S- and Te-bonded molecules we find a large asymmetry in
the spin-currents as a function of the bias, although the $I$-$V$ is rather
symmetric. This leads to a smooth although not monotonic dependence of the
magnetoresistance over the bias. In contrast, in the case of a STM-type
geometry we demonstrate that the spin-current and the magnetoresistance can be
drastically changed with bias. This is the result of a resonance between a
spin-polarized surface state of the substrate and the $d$-shell band-edge of
the tip.",0610866v1
2006-11-21,Resonating Valence Bond States in 2 and 3D: Brief History and Recent Examples,"Resonating Valence Bond states are quantum spin liquids, having low energy
spin-half (spinon) or spin-1 excitations. Although spins are `disordered', they
posses subtle topological orders and some times chiral orders. RVB states are
easily appreciated and seem natural in the quantum fluctuation dominated 1D
world. In 2 and 3D, competing orders such as antiferromagnetism, charge order
or even superconductivity often hide an underlying robust quantum spin liquid
state. Introduction of additional spin interactions or doping of delocalized
charges, or finite temperatures, could frustrate the long range magnetic order
and reveal a robust RVB state. To this extent they are natural in 2D and above.
We present a brief history of insulating RVB states. Then we summarise our own
recent theory of RVB states for 2 and 3D systems, including some newly
synthesised ones: i) boron doped diamond, ii) \nxcob, iii) quasi 2D organic
conductors and iv) a 2D graphene sheet.",0611553v1
2007-01-31,Nuclear Magnetic Resonance Study of Ultrananocrystalline Diamonds,"We report on a nuclear magnetic resonance (NMR) study of ultrananocrystalline
diamond (UNCD) materials produced by detonation technique. Analysis of the 13C
and 1H NMR spectra, spin-spin and spin-lattice relaxation times in purified
UNCD samples is presented. Our measurements show that UNCD particles consist of
a diamond core that is partially covered by a sp2-carbon fullerene-like shell.
The uncovered part of outer diamond surface comprises a number of hydrocarbon
groups that saturate the dangling bonds. Our findings are discussed along with
recent calculations of the UNCD structure. Significant increase in the
spin-lattice relaxation rate (in comparison with that of natural diamond), as
well as stretched exponential character of the magnetization recovery, are
attributed to the interaction of nuclear spins with paramagnetic centers which
are likely fabrication-driven dangling bonds with unpaired electrons. We show
that these centers are located mainly at the interface between the diamond core
and shell.",0701771v1
2007-08-02,Spin-Valley Kondo Effect in Multi-electron Silicon Quantum Dots,"We study the spin-valley Kondo effect of a silicon quantum dot occupied by $%
\mathcal{N}$ electrons, with $\mathcal{N}$ up to four. We show that the Kondo
resonance appears in the $\mathcal{N}=1,2,3$ Coulomb blockade regimes, but not
in the $\mathcal{N}=4$ one, in contrast to the spin-1/2 Kondo effect, which
only occurs at $\mathcal{N}=$ odd. Assuming large orbital level spacings, the
energy states of the dot can be simply characterized by fourfold spin-valley
degrees of freedom. The density of states (DOS) is obtained as a function of
temperature and applied magnetic field using a finite-U equation-of-motion
approach. The structure in the DOS can be detected in transport experiments.
The Kondo resonance is split by the Zeeman splitting and valley splitting for
double- and triple-electron Si dots, in a similar fashion to single-electron
ones. The peak structure and splitting patterns are much richer for the
spin-valley Kondo effect than for the pure spin Kondo effect.",0708.0408v1
2007-09-04,Chaotic dynamics of two 1/2 spin-qubit system in the optical cavity,"Spin systems are one of the most promising candidates for quantum
computation. At the same time control of a system's quantum state during time
evolution is one of the actual problems. It is usually considered that to hold
well-known resonance condition in magnetic resonance is sufficient to control
spin system. But because of nonlinearity of the system, obstructions of control
of system's quantum state may emerge.
  In particular quantum dynamics of two 1/2 spin-qubit system in the optical
cavity is studied in this work. The problem under study is a generalization of
paradigmatic model for Cavity Quantum Electrodynamics of James-Cummings model
in case of interacting spins. In this work it is shown that dynamics is chaotic
when taking into account center-of-mass motion of the qubit and recoil effect.
And besides even in case of zero detuning chaotic dynamics emerges in the
system. It is also shown in this work that because of the chaotic dynamics the
system execute irreversible transition from pure quantum-mechanical state to
mixed one. Irreversibility in its turn is an obstacle for controlling state of
quantum-mechanical system.",0709.0496v1
2007-09-27,Spin-liquid dynamics of pyrochlore magnets Gd2Ti2O7 and Gd2Sn2O7,"The spin-liquid phase of two highly frustrated pyrochlore magnets Gd2Ti2O7
and Gd2Sn2O7 is probed using electron spin resonance in the temperature range
1.3 - 30 K. The deviation of the absorption line from the paramagnetic position
\nu =\gamma H observed in both compounds below the Curie-Weiss temperature
\Theta_CW ~ 10 K, suggests an opening up of a gap in the excitation spectra. On
cooling to 1.3 K (which is above the ordering transition T_N ~ 1.0 K) the
resonance spectrum is transformed into a wide band of excitations with the gap
amounting to \Delta ~ 26 GHz (1.2 K) in Gd2Ti2O7 and 18 GHz (0.8 K) in
Gd2Sn2O7. The gaps increase linearly with the external magnetic field. For
Gd2Ti2O7 this branch co-exists with an additional nearly paramagnetic line
absent in Gd2Sn2O7. These low lying excitations with gaps, which are preformed
in the spin-liquid state, may be interpreted as collective spin modes split by
the single-ion anisotropy.",0709.4379v1
2008-04-29,Spin-magnetophonon level splitting in semimagnetic quantum wells,"Spin-magnetophonon level splitting in a quantum well made of a semimagnetic
wide gap semiconductor is considered. The semimagnetic semiconductors are
characterized by a large effective $g$ factor. The resonance conditions
$\hbar\omega_{\rm LO}=\mu_BgB$ for the spin flip between two Zeeman levels due
to interaction with longitudinal optical phonons can be achieved sweeping
magnetic field $B$. This condition is studied in quantum wells. It is shown
that it leads to a level splitting that is dependent on the electron-phonon
coupling strength as well as on the spin-orbit interaction in this structure.
  We treat in detail the Rashba model for the spin-orbit interaction assuming
that the quantum well lacks inversion symmetry and briefly discuss other
models. The resonant transmission and reflection of light by the well is
suggested as a suitable experimental probe of the level splitting.",0804.4654v1
2008-09-17,Enhanced spin Hall effect by resonant skew scattering in orbital-selective Kondo effect,"The enhanced spin Hall effect in Au metal due to the resonant skew scattering
is studied with first-principles band structure calculations. Especially the
gigantic spin Hall angle $\gamma_S \cong 0.1$ observed recently (T.Seki et al.,
Nature Materials {\bf 7}, 125 (2008)) is attributed to the orbital-dependent
Kondo effect of Fe in the Au host metal, where the $t_{2g}$-orbitals are in the
mixed-valence region while $e_g$-orbitals are in the Kondo limit. The enhanced
spin-orbit interaction by the electron correlation in the $t_{2g}$-orbitals
leads to the gigantic spin Hall effect. Impurities with 5d orbitals are also
discussed.",0809.2921v1
2008-10-06,Testing a possible W and Z structure at the LHC/CERN,"One of the first channels to be experimentally analyzed at the LHC is $ p + p
\longrightarrow l^+ + l ^- + X $. A resonance in this channel would be a clear
indication of a new gauge neutral boson, as proposed in many extended models.
In this paper we call attention to the possibility that the new resonance in
this channel could have spin zero. A new high mass spin zero state could be a
strong indication of the composite nature of the standard model particles. We
have made a comparison between spin zero and spin one for the new hypothetical
heavy gauge particle production and decays and we show some distributions that
can easily identify their spins.",0810.1027v2
2008-12-12,"Spin diffusion and magnetic eigenoscillations confined to single molecular layers in the organic conductors kappa-(BEDT-TTF)_2Cu[N(CN)_2X (X=Cl, Br)","The layered organic compounds, kappa-(BEDT-TTF)_2Cu[N(CN)_2X (X=Cl, Br) are
metals at ambient temperatures. At low temperatures, the Cl compound is a
weakly ferromagnetic Mott insulator while the isostructural Br compound is a
superconductor. We find by conduction electron spin resonance (CESR) and
antiferromagnetic resonance (AFMR) an extreme anisotropy of spin transport and
magnetic interactions in these materials. In the metallic state spin diffusion
is confined to single molecular layers within the spin lifetime of 10^-9 s.
Electrons diffuse several hundreds of nm without hopping to the next molecular
layer. In the magnetically ordered insulating phase of the Cl compound we
observe and calculate the four AFMR modes of the weakly coupled single
molecular layers. The inter-plane exchange field is comparable or less than the
typically 1 mT dipolar field and almost 10^6 times less than the intra-layer
exchange field.",0812.2383v1
2009-01-09,Collective spin excitations in a quantum spin ladder probed by high-resolution Resonant Inelastic X-ray Scattering,"We investigate magnetic excitations in the spin-ladder compound
Sr$_{14}$Cu$_{24}$O$_{41}$ using high-resolution Cu $L_3$-edge Resonant
Inelastic X-ray Scattering (RIXS). Our findings demonstrate that RIXS couples
to collective spin excitations from a quantum spin-liquid ground state. In
contrast to Inelastic Neutron Scattering (INS), the RIXS cross section changes
only moderately over the entire Brillouin Zone (BZ), revealing a high
sensitivity also at small momentum transfers. The two-triplon energy gap is
found to be $100\pm 30$ meV. Our results are supported by calculations within
an effective Hubbard model for a finite-size cluster.",0901.1331v2
2009-04-09,Resonant tunneling-based spin ratchets,"We outline a generic ratchet mechanism for creating directed spin-polarized
currents in ac-driven double well or double dot structures by employing
resonant spin transfer through the system engineered by local external magnetic
fields. We show its applicability to semiconductor nanostructures by
considering coherent transport through two coupled lateral quantum dots, where
the energy levels of the two dots exhibit opposite Zeeman spin splitting. We
perform numerical quantum mechanical calculations for the I-V characteristics
of this system in the nonlinear regime, which requires a self-consistent
treatment of the charge redistribution due to the applied finite bias. We show
that this setting enables nonzero averaged net spin currents in the absence of
net charge transport.",0904.1518v1
2009-06-30,Cooling a magnetic resonance force microscope via the dynamical back-action of nuclear spins,"We analyze the back-action influence of nuclear spins on the motion of the
cantilever of a magnetic force resonance microscope. We calculate the
contribution of nuclear spins to the damping and frequency shift of the
cantilever. We show that, at the Rabi frequency, the energy exchange between
the cantilever and the spin system cools or heats the cantilever depending on
the sign of the high-frequency detuning. We also show that the spin noise leads
to a significant damping of the cantilever motion.",0906.5420v2
2009-12-18,A superconducting cavity bus for single Nitrogen Vacancy defect centres in diamond,"Circuit-QED has demonstrated very strong coupling between individual
microwave photons trapped in a superconducting coplanar resonator and nearby
superconducting qubits. In this work we show how, by designing a novel
interconnect, one can strongly connect the superconducting resonator, via a
magnetic interaction, to a small number (perhaps single), of electronic spins.
By choosing the electronic spin to be within a Nitrogen Vacancy centre in
diamond one can perform optical readout, polarization and control of this
electron spin using microwave and radio frequency irradiation. More
importantly, by utilising Nitrogen Vacancy centres with nearby 13C nuclei,
using this interconnect, one has the potential build a quantum device where the
nuclear spin qubits are connected over centimeter distances via the Nitrogen
Vacancy electronic spins interacting through the superconducting bus.",0912.3586v1
2009-12-30,Pulsed Nuclear Pumping and Spin Diffusion in a Single Charged Quantum Dot,"We report the observation of a feedback process between the nuclear spins in
a single charged quantum dot and its trion transition, driven by a periodic
sequence of optical pulses. The pulse sequence intersperses off-resonant
ultrafast pulses for coherent electron-spin rotation and resonant narrow-band
optical pumping. The feedback manifests as a hysteretic triangle-like pattern
in the free-induction-decay of the single spin. We present a simple,
quasi-analytic numerical model to describe this observation, indicating that
the feedback process results from the countering effects of optical nuclear
pumping and nuclear spin-diffusion inside the quantum dot. This effect allows
dynamic tuning of the electron Larmor frequency to a value determined by the
pulse timing, potentially allowing more complex coherent control operations.",0912.5401v1
2010-04-02,Electron spin coherence and electron nuclear double resonance of Bi donors in natural Si,"Donors in silicon hold considerable promise for emerging quantum
technologies, due to the their uniquely long electron spin coherence times. Bi
donors in silicon differ from P and other Group V donors in several significant
respects: they have the strongest binding energy (70.98 meV), a large nuclear
spin (I = 9/2) and strong hyperfine coupling constant (A = 1475.4 MHz). These
larger energy scales allow a detailed test of theoretical models describing the
spectral diffusion mechanism that is known to govern the electron spin
coherence time (T2e) of P-donors in natural silicon. We report the electron
nuclear double resonance spectra of the Bi donor, across the range 200 MHz to
1.4 GHz, and confirm that coherence transfer is possible between electron and
nuclear spin degrees of freedom at these higher frequencies.",1004.0340v3
2010-07-13,Asymmetric optical nuclear spin pumping in a single uncharged quantum dot,"A highly asymmetric dynamic nuclear spin pumping is observed in a single self
assembled InGaAs quantum dot subject to resonant optical pumping of the neutral
exciton transition leading to a large maximum polarization of 54%. This dynamic
nuclear polarization is found to be much stronger following pumping of the
higher energy Zeeman state. Time-resolved measurements allow us to directly
monitor the buildup of the nuclear spin polarization in real time and to
quantitatively study the dynamics of the process. A strong dependence of the
observed dynamic nuclear polarization on the applied magnetic field is found,
with resonances in the pumping efficiency being observed for particular
magnetic fields. We develop a model that fully accounts for the observed
behaviour, where the pumping of the nuclear spin system is due to
hyperfine-mediated spin flip transitions between the states of the neutral
exciton manifold.",1007.2145v2
2010-09-01,Observation of heavy-hole hyperfine interaction in quantum dots,"We measure the strength and the sign of hyperfine interaction of a heavy-hole
with nuclear spins in single self-assembled quantum dots. Our experiments
utilize the locking of a quantum dot resonance to an incident laser frequency
to generate nuclear spin polarization. By monitoring the resulting Overhauser
shift of optical transitions that are split either by electron or exciton
Zeeman energy with respect to the locked transition using resonance
fluorescence, we find that the ratio of the heavy-hole and electron hyperfine
interactions is -0.09 +/- 0.02 in two QDs. Since hyperfine interactions
constitute the principal decoherence source for spin qubits, we expect our
results to be important for efforts aimed at using heavy-hole spins in
solid-state quantum information processing. The novel spectroscopic technique
we develop also brings new insights to the nuclear-spin mediated locking
mechanism in quantum dots.",1009.0181v1
2011-11-22,Magnetic excitations in L-edge resonant inelastic x-ray scattering from one-dimensional cuprates,"We study the magnetic excitation spectra of L-edge resonant inelastic x-ray
scattering (RIXS) from the spin singlet ground state in one-dimensional undoped
cuprates. Analyzing the transition amplitudes of the magnetic excitations in
the second-order dipole allowed process, we find that the magnetic excitations
are brought about not only on the core-hole site but also on the neighboring
sites. The RIXS spectra are expressed by the one-spin correlation function in
the scattering channel with changing polarization, and the two-spin correlation
function in the scattering channel without changing polarization. The latter
could not be brought about within the so-called UCL approximation. We calculate
these correlation functions on a finite-size ring. An application to the
possible RIXS spectra in Sr_2CuO_3 demonstrates that the contribution of the
two-spin correlation function could be larger than that of the one-spin
correlation function in the \sigma polarization for the momentum transfer
around the zone center.",1111.5078v1
2012-01-09,Manipulating dipolar and spin-exchange interactions in spin-1 Bose-Einstein condensates,"It remains a challenge to independently manipulate the magnetic dipolar and
the spin-exchange interactions, which are entangled in many spin systems,
particularly in spin-1 Bose-Einstein condensates. For this purpose, we put
forward a sequence of rf pulses and the periodic dynamical decoupling sequence
of optical Feshbach resonance pulses to control the dipolar and the
spin-exchange interactions, respectively. Our analytic results and the
numerical simulations demonstrate that either of the two interactions can be
suppressed to make the other dominate the spin dynamics; furthermore, both of
the interactions can be simultaneously suppressed to realize
spinor-condensate-based magnetometers with a higher sensitivity. This
manipulation method may find its wide applications in magnetic resonance and
spintronics.",1201.1779v3
2012-07-24,'Kondo state' and Kondo resonance in a two-dimensional electron gas,"The delicate balance of spin-screening and spin-aligning interactions
determines many of the peculiar properties of dilute magnetic systems. We study
a surface-supported all-organic multi-impurity Kondo spin system at the atomic
scale by low-temperature scanning tunnelling microscopy and -spectroscopy. The
model system consists of spin-1/2 radicals that are aligned in one-dimensional
chains and interact via a ferromagnetic RKKY interaction mediated by the 2DEG
of the supporting substrate. Due to the RKKY-induced enhanced depopulation of
one spin-subband in the 2DEG, we finally succeeded to detect the so far
unobserved 'Kondo state' as opposed to the well-established Kondo resonance.
Its cloud of screening electrons, that are virtually bound to the radicals
below the Kondo temperature, represents the extended exchange hole of the
ferromagnetically polarized spin chain imaged here in real space.",1207.5613v1
2013-05-23,Quantum Phase Transition between Z2 spin liquid and columnar Valence Bond Crystals on a Triangular lattice,"We study the quantum phase transition between the $Z_2$ spin liquid and
valence bond solid (VBS) orders on a triangular lattice. With a fully isotropic
triangular lattice, the transition from a columnar or resonating-plaquette VBS
order can be either first order or there could be two transitions with an
intermediate phase. If the transition splits into two, then the $Z_2$ spin
liquid will first experience a first order $q=3$ Potts transition to a new
nematic $Z_2$ spin liquid that breaks the $2\pi/3$ lattice rotation symmetry
(but retain translation symmetry unlike the VBS states). The second transition
will then take this new nematic $Z_2$ spin liquid to a columnar or
resonating-plaquette VBS state through a second order $3d$ XY$^*$ transition.
On a distorted triangular lattice, the degeneracy between some of the different
columnar VBS orders is lifted, and the phase transition can reduce to a single
$3d$ XY$^*$ transition.",1305.5553v3
2013-05-25,Spin-current induced Kondo-resonance splitting of a single cobalt atom,"We use a low-temperature scanning tunneling microscope to study the interplay
between the Kondo effect of a single-atom contact and a spin current. To this
end, a nickel tip is coated by a thick layer of copper and brought into contact
with a single Co atom adsorbed on a Cu(100) surface. We show that upon contact
the Kondo resonance of Co is spin split and attribute the splitting to the spin
current produced by the nickel tip and flowing across the copper spacer. A
quantitative line shape analysis indicates that the spin polarization of the
junction amounts up to 18%, but decreases when a pristine nickel tip is
directly contacted to the Co atom.",1305.5903v6
2013-06-15,Circuit QED with Hole-Spin Qubits in Ge/Si Nanowire Quantum Dots,"We propose a setup for universal and electrically controlled quantum
information processing with hole spins in Ge/Si core/shell nanowire quantum
dots (NW QDs). Single-qubit gates can be driven through electric-dipole-induced
spin resonance, with spin-flip times shorter than 100 ps. Long-distance
qubit-qubit coupling can be mediated by the cavity electric field of a
superconducting transmission line resonator, where we show that operation times
below 20 ns seem feasible for the entangling square-root-of-iSWAP gate. The
absence of Dresselhaus spin-orbit interaction (SOI) and the presence of an
unusually strong Rashba-type SOI enable precise control over the transverse
qubit coupling via an externally applied, perpendicular electric field. The
latter serves as an on-off switch for quantum gates and also provides control
over the g factor, so single- and two-qubit gates can be operated
independently. Remarkably, we find that idle qubits are insensitive to charge
noise and phonons, and we discuss strategies for enhancing noise-limited gate
fidelities.",1306.3596v2
2013-11-26,Spin noise spectroscopy of a single-quantum-well microcavity,"We report on the first experimental observation of spin noise in a single
semiconductor quantum well embedded into a microcavity. The great
cavity-enhanced sensitivity to fluctuations of optical anisotropy has allowed
us to measure the Kerr rotation and ellipticity noise spectra in the strong
coupling regime. The spin noise spectra clearly show two resonant features: a
conventional magneto-resonant component shifting towards higher frequencies
with magnetic field and an unusual ""nonmagnetic"" component centered at zero
frequency and getting suppressed with increasing magnetic field. We attribute
the first of them to the Larmor precession of free electron spins, while the
second one being presumably due to hyperfine electron-nuclei spin interactions.",1311.6587v2
2014-01-23,The suppression of electron correlations in the collapsed tetragonal phase of CaFe2As2 under ambient pressure demonstrated by 75As NMR-NQR measurements,"The static and the dynamic spin correlations in the low temperature collapsed
tetragonal and the high temperature tetragonal phase in CaFe2As2 have been
investigated by 75As nuclear magnetic resonance (NMR) and nuclear quadrupole
resonance (NQR) measurements.
  Through the temperature (T) dependence of the nuclear spin lattice relaxation
rates (1/T1) and the Knight shifts, although stripe-type antiferromagnetic
(AFM) spin correlations are realized in the high temperature tetragonal phase,
no trace of the AFM spin correlations can be found in the non-superconducting,
low temperature, collapsed tetragonal (cT) phase.
  Given that there is no magnetic broadening in 75As NMR spectra, together with
the T-independent behavior of magnetic susceptibility (x) and the T dependence
of 1/T1Tx, we conclude that Fe spin correlations are completely quenched
statically and dynamically in the non-superconducting cT phase in CaFe2As2.",1401.6191v1
2014-02-13,Unusual spin fluctuations and magnetic frustration in olivine and non-olivine LiCoPO$_4$ detected by $^{31}$P and $^7$Li nuclear magnetic resonance,"We report $^{31}$P and $^{7}$Li nuclear magnetic resonance (NMR) studies in
new non-olivine LiZnPO$_4$-type LiCoPO$_4^\text{tetra}$ microcrystals, where
the Co$^{2+}$ ions are tetrahedrally coordinated. Olivine LiCoPO$_4$, which was
directly transformed from LiCoPO$_4^\text{tetra}$ by an annealing process, was
also studied and compared. The uniform bulk magnetic susceptibility and the
$^{31}$P Knight shift obey the Curie-Weiss law for both materials with a high
spin Co$^{2+}$ ($3d^7$, $S=3/2$), but the Weiss temperature $\Theta$ and the
effective magnetic moment $\mu_\text{eff}$ are considerably smaller in
LiCoPO$_4^\text{tetra}$. The spin-lattice relaxation rate $T_1^{-1}$ reveals a
quite different nature of the spin dynamics in the paramagnetic state of both
materials. Our NMR results imply that strong geometrical spin frustration
occurs in tetrahedrally coordinated LiCoPO$_4$, which may lead to the
incommensurate magnetic ordering.",1402.3082v2
2014-04-29,Establishing the fundamental magnetic interactions in the chiral skyrmionic Mott insulator Cu2OSeO3 by terahertz electron spin resonance,"The recent discovery of skyrmions in Cu$_2$OSeO$_3$ has established a new
platform to create and manipulate skyrmionic spin textures. We use high-field
electron spin resonance (ESR) spectroscopy combining a terahertz free electron
laser and pulsed magnetic fields up to 64 T to probe and quantify its
microscopic spin-spin interactions. Besides providing direct access to the
long-wavelength Goldstone mode, this technique probes also the high-energy part
of the excitation spectrum which is inaccessible by standard low-frequency ESR.
Fitting the behavior of the observed modes in magnetic field to a theoretical
framework establishes experimentally that the fundamental magnetic building
blocks of this skyrmionic magnet are rigid, highly entangled and weakly coupled
tetrahedra.",1404.7319v2
2014-10-14,Magnetic resonance detection of individual proton spins using a quantum reporter network,"We demonstrate a method of magnetic resonance imaging with single
nuclear-spin sensitivity under ambient conditions. It employs a network of
isolated electronic-spin quantum bits (qubits) that act as quantum reporters on
the surface of high purity diamond. The reporter spins are localized with
nanometer-scale uncertainty, and their quantum state is coherently manipulated
and measured optically via a proximal nitrogen-vacancy (NV) color center
located a few nanometers below the diamond surface. The quantum reporter
network is then used for sensing, coherent coupling and imaging individual
proton spins on the diamond surface with angstrom resolution. This approach may
enable direct structural imaging of complex molecules that cannot be accessed
from bulk studies. It realizes a new platform for probing novel materials,
monitoring chemical reactions, and manipulation of complex systems on surfaces
at a quantum level.",1410.3750v1
2015-03-06,Electric-dipole-induced spin resonance in a lateral double quantum dot incorporating two single domain nanomagnets,"On-chip magnets can be used to implement relatively large local magnetic
field gradients in na- noelectronic circuits. Such field gradients provide
possibilities for all-electrical control of electron spin-qubits where
important coupling constants depend crucially on the detailed field
distribution. We present a double quantum dot (QD) hybrid device laterally
defined in a GaAs / AlGaAs het- erostructure which incorporates two single
domain nanomagnets. They have appreciably different coercive fields which
allows us to realize four distinct configurations of the local inhomogeneous
field distribution. We perform dc transport spectroscopy in the Pauli-spin
blockade regime as well as electric-dipole-induced spin resonance (EDSR)
measurements to explore our hybrid nanodevice. Characterizing the two
nanomagnets we find excellent agreement with numerical simulations. By
comparing the EDSR measurements with a second double QD incorporating just one
nanomagnet we reveal an important advantage of having one magnet per QD: It
facilitates strong field gradients in each QD and allows to control the
electron spins individually for instance in an EDSR experi- ment. With just one
single domain nanomagnet and common QD geometries EDSR can likely be performed
only in one QD.",1503.01938v1
2015-06-15,Detection of topological states in two-dimensional Dirac systems by the dynamic spin susceptibility,"We discuss dynamic spin susceptibility (DSS) in two-dimensional (2D) Dirac
electrons with spin-orbit interactions to characterize topological insulators.
The imaginary part of the DSS appears as an absorption rate in response to a
transverse ac magnetic field, just as in an electron spin resonance experiment
for localized spin systems. We found that when the system is in a static
magnetic field, the topological state can be identified by an anomalous
resonant peak of the imaginary part of the DSS as a function of the frequency
of the transverse magnetic field $\omega$. In the absence of a static magnetic
field, the imaginary part of the DSS becomes a continuous function of $\omega$
with a threshold frequency $\omega_{\rm c}$. In this case, the topological and
the trivial phases can also be distinguished by the values of $\omega_{\rm c}$
and by the line shapes. Thus the DSS is an experimentally observable physical
quantity to characterize a topological insulator directly from bulk properties,
without observing a topological transition.",1506.04691v2
2015-07-10,The quantum mechanics correspondence principle for spin systems and its application for some magnetic resonance problems,"Problems of interacting quantum magnetic moments become exponentially complex
with increasing number of particles. As a result, classical equations are often
used but the validity of reduction of a quantum problem to a classical problem
should be justified. In this paper we formulate the correspondence principle,
which shows that the classical equations of motion for a system of dipole
interacting spins have identical form with the quantum equations. The classical
simulations based on the correspondence principle for spin systems provide a
practical tool to study different macroscopic spin physics phenomena. Three
classical magnetic resonance problems in solids are considered as examples -
free induction decay (FID), spin echo and the Pake doublet.",1507.03043v1
2015-10-09,Electron Spin Resonance in a Two-Dimensional Fermi Liquid with Spin-Orbit Coupling,"Electron spin resonance (ESR) is usually interpreted as a single-particle
phenomenon protected from the effect of many-body correlations. We show that
this is not the case in a two-dimensional Fermi liquid (FL) with spin-orbit
coupling (SOC). Depending on whether the magnetic field is below or above some
critical value, ESR in such a system probes up to three collective chiral-spin
modes, augmented by the presence of the field, or the Larmor mode, augmented
both by SOC and FL renormalizations. We argue that ESR can be used as a probe
not only for SOC but also for many-body physics.",1510.02534v2
2016-01-06,All-electrical detection of spin dynamics in magnetic antidot lattices by the inverse spin Hall effect,"The understanding of spin dynamics in laterally confined structures on
sub-micron length scales has become a significant aspect of the development of
novel magnetic storage technologies. Numerous ferromagnetic resonance
measurements, optical characterization by Kerr microscopy and Brillouin light
scattering spectroscopy and x-ray studies were carried out to detect the
dynamics in patterned magnetic antidot lattices. Here, we investigate
Oersted-field driven spin dynamics in rectangular Ni80Fe20/Pt antidot lattices
with different lattice parameters by electrical means and compare them to
micromagnetic simulations. When the system is driven to resonance, a dc voltage
across the length of the sample is detected that changes its sign upon field
reversal, which is in agreement with a rectification mechanism based on the
inverse spin Hall effect. Furthermore, we show that the voltage output scales
linearly with the applied microwave drive in the investigated range of powers.
Our findings have direct implications on the development of engineered
magnonics applications and devices.",1601.01221v1
2016-02-14,Ultra-sensitive nanoscale magnetic field sensors based on resonant spin filtering,"Solid state magnetic field sensors based on magneto-resistance modulation
find direct applications in communication devices, specifically in proximity
detection, rotational reference detection and current sensing. In this work, we
propose sensor structures based on the magneto-resistance physics of resonant
spin-filtering and present device designs catered toward exceptional magnetic
field sensing capabilities. Using the non-equilibrium Green's function spin
transport formalism self consistently coupled to the Poisson's equation, we
present highly-tunable pentalayer magnetic tunnel junction structures that are
capable of exhibiting an ultra-high peak tunnel magneto resistance $(\approx
2500 \%$). We show how this translates to device designs featuring an
ultra-high current sensitivity enhancement of over 300\% in comparison with
typical trilayer MTJ sensors, and a wider tunable range of field sensitivity.
We also demonstrate that a dynamic variation in sensor functionalities with the
structural landscape enables a superior design flexibility over typical
trilayer sensors. An optimal design exhibiting close to a 700\% sensitivity
increase as a result of angle dependent spin filtering is then presented.This
work sets a stage to engineer spintronic building blocks via the design of
functional structures tailored to exhibit ultra-sensitive spin filtering.",1602.04438v1
2016-04-19,Delayed entanglement echo for individual control of a large number of nuclear spins,"Methods for achieving quantum control and detection of individual nuclear
spins by single electrons of solid-state defects play a central role for
quantum information processing and nano-scale nuclear magnetic resonance (NMR).
However, with standard techniques, no more than 8 nuclear spins have been
resolved. Here we develop a method that improves significantly the ability to
spectrally resolve nuclear spins and demonstrate its capabilities with detailed
numerical simulations by using a nitrogen-vacancy (NV) centre as model system.
Based on delayed entanglement control, a technique combining microwave and
radio-frequency (rf) fields, nuclei with resonances in a broad frequency band
can be unambiguously and individually addressed by the sensor electron.
Additionally the spectral resolution can extend beyond the electron spin
relaxation time by using a long-lived qubit memory. Our method greatly
increases the number of useful register qubits accessible to a defect centre
and improves the signals of nano-scale NMR.",1604.05731v1
2016-05-18,Collective Strong Coupling with Homogeneous Rabi Frequencies using a 3D Lumped Element Microwave Resonator,"We design and implement 3D lumped element microwave cavities for the coherent
and uniform coupling to electron spins hosted by nitrogen vacancy centers in
diamond. Our design spatially focuses the magnetic field to a small mode
volume. We achieve large homogeneous single spin coupling rates, with an
enhancement of the single spin Rabi frequency of more than one order of
magnitude compared to standard 3D cavities with a fundamental resonance at
\SI{3}{GHz}. Finite element simulations confirm that the magnetic field
component is homogeneous throughout the entire sample volume, with a RMS
deviation of 1.54\%. With a sample containing $10^{17}$ nitrogen vacancy
electron spins we achieve a collective coupling strength of
$\Omega=\SI{12}{MHz}$, a cooperativity factor $C=27$ and clearly enter the
strong coupling regime. This allows to interface a macroscopic spin ensemble
with microwave circuits, and the homogeneous Rabi frequency paves the way to
manipulate the full ensemble population in a coherent way.",1605.05554v1
2016-07-05,Characterizing Si:P quantum dot qubits with spin resonance techniques,"Quantum dots patterned by atomically precise placement of phosphorus donors
in single crystal silicon have long spin lifetimes, advantages in
addressability, large exchange tunability, and are readily available
few-electron systems. To be utilized as quantum bits, it is important to
non-invasively characterise these donor quantum dots post fabrication and
extract the number of bound electron and nuclear spins as well as their
locations. Here, we propose a metrology technique based on electron spin
resonance (ESR) measurements with the on-chip circuitry already needed for
qubit manipulation to obtain atomic scale information about donor quantum dots
and their spin configurations. Using atomistic tight-binding technique and
Hartree self-consistent field approximation, we show that the ESR transition
frequencies are directly related to the number of donors, electrons, and their
locations through the electron-nuclear hyperfine interaction.",1607.01086v1
2016-07-13,Surface state dominated spin-charge current conversion in topological insulator/ferromagnetic insulator heterostructures,"We report the observation of ferromagnetic resonance-driven spin pumping
signals at room temperature in three-dimensional topological insulator thin
films -- Bi2Se3 and (Bi,Sb)2Te3 -- deposited by molecular beam epitaxy on
yttrium iron garnet thin films. By systematically varying the Bi2Se3 film
thickness, we show that the spin-charge conversion efficiency, characterized by
the inverse Rashba-Edelstein effect length (lambda_IREE), increases
dramatically as the film thickness is increased from 2 quintuple layers,
saturating above 6 quintuple layers. This suggests a dominant role of surface
states in spin and charge interconversion in topological insulator/ferromagnet
heterostructures. Our conclusion is further corroborated by studying a series
of YIG/(BiSb)2Te3 heterostructures. Finally, we use the ferromagnetic resonance
linewidth broadening and the inverse Rashba-Edelstein signals to determine the
effective interfacial spin mixing conductance and lambda_IREE.",1607.03872v1
2017-07-25,Non-equilibrium nuclear spin distribution function in quantum dots subject to periodic pulses,"Electron spin dephasing in a singly charged semiconductor quantum dot can
partially be suppressed by periodic laser pulsing. We propose a semi-classical
approach describing the decoherence of the electron spin polarization governed
by the hyperfine interaction with the nuclear spins as well as the
probabilistic nature of the photon absorption. We use the steady-state Floquet
condition to analytically derive two subclasses of resonance conditions
excellently predicting the peak locations in the part of the Overhauser field
distribution which is projected in the direction of the external magnetic
field. As a consequence of the periodic pulsing, a non-equilibrium distribution
develops as a function of time. The numerical simulation of the coupled
dynamics reveals the influence of the hyperfine coupling constant distribution
onto the evolution of the electron spin polarisation before the next laser
pulse. Experimental indications are provided for both subclasses of resonance
conditions.",1707.07841v1
2017-08-30,Phase-Encoded Hyperpolarized Nanodiamond for Magnetic Resonance Imaging,"Surface-functionalized nanomaterials can act as theranostic agents that
detect disease and track biological processes using hyperpolarized magnetic
resonance imaging (MRI). Candidate materials are sparse however, requiring
spinful nuclei with long spin-lattice relaxation (T1) and spin-dephasing times
(T2), together with a reservoir of electrons to impart hyperpolarization. Here,
we demonstrate the versatility of the nanodiamond material system for
hyperpolarized 13C MRI, making use of its intrinsic paramagnetic defect
centers, hours-long nuclear T1 times, and T2 times suitable for spatially
resolving millimeter-scale structures. Combining these properties, we enable a
new imaging modality that exploits the phase-contrast between spins encoded
with a hyperpolarization that is aligned, or anti-aligned with the external
magnetic field. The use of phase-encoded hyperpolarization allows nanodiamonds
to be tagged and distinguished in an MRI based on their spin-orientation alone,
and could permit the action of specific bio-functionalized complexes to be
directly compared and imaged.",1709.01851v1
2018-05-31,Spin-orbit coupling and resonances in the conductance of quantum wires,"We investigate a possibility of pair electron-electron e-e collisions in a
ballistic wire with spin-orbit coupling and only one populated mode. Unlike in
a spin-degenerate system, a combination of spin-splitting in momentum space
with a momentum-dependent spin-precession opens up a finite phase space for
pair e-e collisions around three distinct positions of the wire's chemical
potential. For a short wire, we calculate corresponding resonant contributions
to the conductance, which have different power-law temperature dependencies,
and, in some cases, vanish if the wire's transverse confinement potential is
symmetric. Our results may explain the recently observed feature at the lower
conductance plateau in InAs wires.",1805.12385v2
2017-05-14,Anomalous thermoelectric properties of a Floquet topological insulator with spin momentum non-orthogonality,"The spin momentum non-orthogonality in 3D topological insulators leads to
modification of the spin texture and brings in an out-of-plane spin
polarization component. Apart from spin texture, the anomalous thermoelectric
properties of these materials are worth studying. In this paper, we have
pointed out that the off resonant light used to irradiate the surface states,
induces a gap, which becomes momentum dependent due to the presence of
non-orthogonal terms in the Hamiltonian. Importantly, to maintain the off
resonant condition of light, the momentum value should satisfy a bound.
Furthermore, the momentum dependent gap causes a topological transition at
higher value of momentum, which is important to analyse the unusual double peak
structure of the Nernst and electrical conductivities.",1705.04948v3
2018-10-13,Spin-torque resonance due to diffusive dynamics at a surface of topological insulator,"We investigate spin-orbit torques on magnetization in an insulating
ferromagnetic (FM) layer that is brought into a close proximity to a
topological insulator (TI). In addition to the well-known field-like spin-orbit
torque, we identify an anisotropic anti-damping-like spin-orbit torque that
originates in a diffusive motion of conduction electrons. This diffusive torque
is vanishing in the limit of zero momentum (i. e. for spatially homogeneous
electric field or current), but may, nevertheless, have a strong effect on
spin-torque resonance at finite frequency provided external field is neither
parallel nor perpendicular to the TI surface. The required electric field
configuration can be created by a grated top gate.",1810.05828v3
2018-12-10,Interactions between non-resonant rf fields and atoms with strong spin-exchange collisions,"We study the interactions between oscillating non-resonant rf fields and
atoms with strong spin-exchange collisions in the presence of a weak dc
magnetic field. We find that the atomic Larmor precession frequency shows a new
functional form to the rf field parameters when the spin-exchange collision
rate is tuned. In the weak rf field amplitude regime, a strong modification of
atomic Larmor frequency appears when the spin-exchange rate is comparable to
the rf field frequency. This new effect has been neglected before due to its
narrow observation window. We compare the experimental results with density
matrix calculations, and explain the data by an underdamped oscillator model.
When the rf field amplitude is large, there is a minimum atomic gyromagnetic
ratio point due to the rf photon dressing, and we find that strong
spin-exchange interactions modify the position of such a point.",1812.03772v2
2020-04-29,Dynamics of Colombo's Top: Generating Exoplanet Obliquities from Planet-Disk Interactions,"Large planetary spin-orbit misalignments (obliquities) may strongly influence
atmospheric circulation and tidal heating in the planet. A promising avenue to
generate obliquities is via spin-orbit resonances, where the spin and orbital
precession frequencies of the planet cross each other as the system evolves in
time. One such mechanism involves a dissipating (mass-losing) protoplanetary
disk that drives orbital precession of an interior planet. We study this
scenario analytically in this paper, and obtain the mapping between the general
initial spin orientation and the final obliquity. We show that (i) under
adiabatic evolution (i.e. the disk dissipates at a sufficiently slow rate), the
final planetary obliquity as a function of the initial spin orientation
bifurcates into distinct tracks governed by interactions with the resonance;
(ii) under nonadiabatic evolution, a broad range of obliquities can be excited.
We obtain analytical expressions for the final obliquities for various regimes
of parameter space. The dynamical system studied in this paper is an example of
""Colombo's top"", and our analysis and results can be adapted to other
applications.",2004.14380v3
2016-03-25,Large spin pumping effect in antisymmetric precession of Ni$_{79}$Fe$_{21}$/Ru/Ni$_{79}$Fe$_{21}$,"In magnetic trilayer structures, a contribution to the Gilbert damping of
ferromagnetic resonance arises from spin currents pumped from one layer to
another. This contribution has been demonstrated for layers with weakly
coupled, separated resonances, where magnetization dynamics are excited
predominantly in one layer and the other layer acts as a spin sink. Here we
show that trilayer structures in which magnetizations are excited
simultaneously, antisymmetrically, show a spin-pumping effect roughly twice as
large. The antisymmetric (optical) mode of antiferromagnetically coupled
Ni$_{79}$Fe$_{21}$(8nm)/Ru/Ni$_{79}$Fe$_{21}$(8nm) trilayers shows a Gilbert
damping constant greater than that of the symmetric (acoustic) mode by an
amount as large as the intrinsic damping of Py ($\Delta
\alpha\simeq\textrm{0.006}$). The effect is shown equally in field-normal and
field-parallel to film plane geometries over 3-25 GHz. The results confirm a
prediction of the spin pumping model and have implications for the use of
synthetic antiferromagnets (SAF)-structures in GHz devices.",1603.07977v1
2017-02-14,A Method for Measurement of Spin-Spin Couplings with sub-mHz Precision Using Zero- to Ultralow-Field Nuclear Magnetic Resonance,"We present a method which allows for the extraction of physical quantities
directly from zero- to ultralow-field nuclear magnetic resonance (ZULF NMR)
data. A numerical density matrix evolution is used to simulate ZULF NMR spectra
of several molecules in order to fit experimental data. The method is utilized
to determine the indirect spin-spin couplings ($J$-couplings) in these, which
is achieved with precision of $10^{-2}$--$10^{-4}$ Hz. The simulated and
measured spectra are compared to earlier research. Agreement and precision
improvement for most of the $J$-coupling estimates are achieved. The
availability of an efficient, flexible fitting method for ZULF NMR enables a
new generation of precision-measurement experiments for spin-dependent
interactions and physics beyond the Standard Model.",1702.04297v2
2017-06-04,Field- and temperature-modulated spin-diode effect in a GMR nanowire with dipolar coupling,"An analytical model of the spin-diode effect induced by resonant
spin-transfer torque in a ferromagnetic bilayer with strong dipolar coupling
provides the resonance frequencies and the lineshapes of the magnetic field
spectra obtained under field or laser-light modulation. The effect of laser
irradiation is accounted for by introducing the temperature dependence of the
saturation magnetization and anisotropy, as well as thermal spin-transfer
torques. The predictions of the model are compared with experimental data
obtained with single Co/Cu/Co spin valves, embedded in nanowires and produced
by electrodeposition. Temperature modulation provides excellent signal-to-noise
ratio. High temperature-modulation frequency is possible because these
nanostructures have a very small heat capacity and are only weakly heat-sunk.
The two forms of modulation give rise to qualitative differences in the spectra
that are accounted for by the model.",1706.01036v1
2019-03-14,Site-selective quantum control in an isotopically enriched 28Si/SiGe quadruple quantum dot,"Silicon spin qubits are a promising quantum computing platform offering long
coherence times, small device sizes, and compatibility with industry-backed
device fabrication techniques. In recent years, high fidelity single-qubit and
two-qubit operations have been demonstrated in Si. Here, we demonstrate
coherent spin control in a quadruple quantum dot fabricated using isotopically
enriched 28Si. We tune the ground state charge configuration of the quadruple
dot down to the single electron regime and demonstrate tunable interdot tunnel
couplings as large as 20 GHz, which enables exchange-based two-qubit gate
operations. Site-selective single spin rotations are achieved using electric
dipole spin resonance in a magnetic field gradient. We execute a resonant-CNOT
gate between two adjacent spins in 270 ns.",1903.05952v1
2021-02-16,Spin-pumping in superconductor-antiferromagnetic insulator bilayers,"We study theoretically spin pumping in bilayers consisting of superconductors
and antiferromagnetic insulators. We consider both compensated and
uncompensated interfaces and include both the regular scattering channel and
the Umklapp scattering channel. We find that at temperatures close to the
critical temperatures and precession frequencies much lower than the gap, the
spin-current is enhanced in superconductors as compared to normal metals.
Otherwise, the spin-current is suppressed. The relevant precession frequencies
where the spin-current in SC/AFI is enhanced compared to NM/AFI is much lower
than the typical resonance frequencies of antiferromagnets, which makes the
detection of this effect experimentally challenging. A possible solution lies
in the shifting of the resonance frequency by a static magnetic field.",2102.08400v2
2021-08-25,High energy spin excitations in the quantum spin liquid candidate Zn-barlowite probed by resonant inelastic x-ray scattering,"A quantum spin liquid is a novel ground state that can support long-range
entanglement between magnetic moments, resulting in exotic spin excitations
involving fractionalized $S=\frac{1}{2}$ spinons. Here, we measure the
excitations in single crystals of the spin liquid candidate Zn-barlowite using
resonant inelastic X-ray scattering. By analyzing the incident polarization and
temperature dependences, we deduce a clear magnetic scattering contribution
forming a broad continuum that surprisingly extends up to $\sim$200 meV
($\sim$14$J$, where $J$ is the magnetic exchange). The excitation spectrum
reveals that significant contributions arise from multiple pairs of spinons
and/or antispinons at high energies.",2108.11506v1
2019-07-18,Understanding the Linewidth of the ESR Spectrum Detected by a Single NV Center in Diamond,"Spectral analysis of electron spin resonance (ESR) is a powerful technique
for various investigations including characterization of spin systems,
measurements of spin concentration, and probing spin dynamics. The
nitrogen-vacancy (NV) center in diamond is a promising magnetic sensor enabling
improvement of ESR sensitivity to the level of a single spin. Therefore,
understanding the nature of NV-detected ESR (NV-ESR) spectrum is critical for
applications to nanoscale ESR. Within this work we investigate the linewidth of
NV-ESR from single substitutional nitrogen centers (called P1 centers). NV-ESR
is detected by a double electron-electron resonance (DEER) technique. By
studying the dependence of the DEER excitation bandwidth on NV-ESR linewidth,
we find that the spectral resolution is improved significantly and eventually
limited by inhomogeneous broadening of the detected P1 ESR. Moreover, we show
that the NV-ESR linewidth can be as narrow as 0.3 MHz.",1907.08156v1
2019-12-09,Strong Spin Squeezing Induced by Weak Squeezing of Light inside a Cavity,"We propose a simple method for generating spin squeezing of atomic ensembles
in a Floquet cavity subject to a weak, detuned two-photon driving. We
demonstrate that {\it the weak squeezing of light inside the cavity can,
counterintuitively, induce strong spin squeezing}. This is achieved by
exploiting the anti-Stokes scattering process of a photon pair interacting with
an atom. Specifically, {\it one photon of the photon pair is scattered into the
cavity resonance by absorbing partially the energy of the other photon whose
remaining energy excites the atom}. The scattering, combined with a Floquet
sideband, provides an alternative mechanism to implement Heisenberg-limited
spin squeezing. Our proposal does {\it not} need multiple classical and
cavity-photon drivings applied to atoms in ensembles, and therefore its
experimental feasibility is greatly improved compared to other cavity-based
schemes. As an example, we demonstrate a possible implementation with a
superconducting resonator coupled to a nitrogen-vacancy electronic-spin
ensemble.",1912.04039v3
2020-02-26,Demonstration of NV-detected ESR spectroscopy at 115 GHz and 4.2 Tesla,"High frequency electron spin resonance (ESR) spectroscopy is an invaluable
tool for identification and characterization of spin systems. Nanoscale ESR
using the nitrogen-vacancy (NV) center has been demonstrated down to the level
of a single spin. However, NV-detected ESR has exclusively been studied at low
magnetic fields, where spectral overlap prevents clear identification of
spectral features. Within this work, we demonstrate NV-detected ESR
measurements of single-substitutional nitrogen impurities in diamond at a NV
Larmor frequency of 115 GHz and the corresponding magnetic field of 4.2 Tesla.
The NV-ESR measurements utilize a double electron-electron resonance sequence
and are performed using both ensemble and single NV spin systems. In the single
NV experiment, chirp pulses are used to improve the population transfer and for
NV-ESR measurements. This work provides the basis for NV-based ESR measurements
of external spins at high magnetic fields.",2002.11845v2
2020-06-07,Sublattice symmetry breaking and ultra low energy excitations in Graphene-on-hBN Heterostructures,"The low-lying states of graphene contain exciting topological properties that
depend on the interplay of different symmetry breaking terms. The corresponding
energy gaps remained unexplored until recently, owing to the low energy scale
of the terms involved (few tens of ueV). These low energy terms include
sublattice splitting, the Rashba and the intrinsic spin-orbit coupling, whose
balance determines the topological properties. In this work, we unravel the
contributions arising from the sublattice and the intrinsic spin orbit
splitting in graphene on hexagonal boron-nitride. Employing
resistively-detected electron spin resonance, we measure a sublattice splitting
of the order of 20E-6 eV, and confirm an intrinsic spin orbit coupling of
approximately 45E-6 eV. The dominance of the latter suggests a topologically
non-trivial state, involving fascinating properties. Electron spin resonance is
a promising route towards unveiling the intriguing band structure at low energy
scales.",2006.04190v1
2021-03-15,"Controlled coherent dynamics of [VO(TPP)], a prototype molecular nuclear qudit with an electronic ancilla","We show that [VO(TPP)] (vanadyl tetraphenylporphyrinate) is a promising
system suitable to implement quantum computation algorithms based on encoding
information in multi-level (qudit) units. Indeed, it embeds an electronic spin
1/2 coupled through hyperfine interaction to a nuclear spin 7/2, both
characterized by remarkable coherence. We demonstrate this by an extensive
broadband nuclear magnetic resonance study, which allow us to characterize the
nuclear spin-Hamiltonian and to measure the spin dephasing time as a function
of the magnetic field. In addition, we combine targeted measurements and
numerical simulations to show that nuclear spin transitions conditioned by the
state of the electronic qubit can be individually addressed and coherently
manipulated by resonant radio-frequency pulses, thanks to the remarkably long
coherence times and the effective quadrupolar coupling induced by the strong
hyperfine coupling. This approach may open new perspectives for developing new
molecular qubit-qudit systems.",2103.08730v1
2021-09-15,Complexes formed in collisions between ultracold alkali-metal diatomic molecules and atoms,"We explore the properties of 3-atom complexes of alkali-metal diatomic
molecules with alkali-metal atoms, which may be formed in ultracold collisions.
We estimate the densities of vibrational states at the energy of atom-diatom
collisions, and find values ranging from 2.2 to 350~K$^{-1}$. However, this
density does not account for electronic near-degeneracy or electron and nuclear
spins. We consider the fine and hyperfine structure expected for such
complexes. The Fermi contact interaction between electron and nuclear spins can
cause spin exchange between atomic and molecular spins. It can drive inelastic
collisions, with resonances of three distinct types, each with a characteristic
width and peak height in the inelastic rate coefficient. Some of these
resonances are broad enough to overlap and produce a background loss rate that
is approximately proportional to the number of outgoing inelastic channels.
Spin exchange can increase the density of states from which laser-induced loss
may occur.",2109.07435v2
2021-12-28,Spin-orbit coupling for close-in planets,"We study the spin evolution of close-in planets in multi-body systems and
present a very general formulation of the spin-orbit problem. This includes a
simple way to probe the spin dynamics from the orbital perturbations, a new
method for computing forced librations and tidal deformation, and general
expressions for the tidal torque and capture probabilities in resonance. We
show that planet-planet perturbations can drive the spin of Earth-size planets
into asynchronous or chaotic states, even for nearly circular orbits. We apply
our results to Mercury and to the KOI-1599 system of two super-Earths in a 3/2
mean motion resonance.",2112.14335v1
2022-01-26,Instability of the ferromagnetic quantum critical point in strongly interacting 2D and 3D electron gases with arbitrary spin-orbit splitting,"In this work we revisit itinerant ferromagnetism in 2D and 3D electron gases
with arbitrary spin-orbit splitting and strong electron-electron interaction.
We identify the resonant scattering processes close to the Fermi surface that
are responsible for the instability of the ferromagnetic quantum critical point
at low temperatures. In contrast to previous theoretical studies, we show that
such processes cannot be fully suppressed even in presence of arbitrary
spin-orbit splitting. A fully self-consistent non-perturbative treatment of the
electron-electron interaction close to the phase transition shows that these
resonant processes always destabilize the ferromagnetic quantum critical point
and lead to a first-order phase transition. Characteristic signatures of these
processes can be measured via the non-analytic dependence of the spin
susceptibility on magnetic field both far away or close to the phase
transition.",2201.10995v1
2022-02-19,"Entangled, Spin-polarized Excitons from Singlet Fission in a Rigid Dimer","Singlet fission, a process that splits a singlet exciton into a biexciton,
has promise in quantum information. We report time-resolved electron
paramagnetic resonance measurements on a molecule, TIPS-BP1$'$, designed to
exhibit strongly state-selective relaxation to specific magnetic spin
sublevels. The resulting optically pumped ""spin polarization"" is a nearly pure
initial state from the ensemble. The long-lived spin coherences modulate the
signal intrinsically, allowing a new measurement scheme that substantially
removes noise and uncertainty in the magnetic resonance spectra. A nonadiabatic
transition theory with a minimal number of spectroscopic parameters allows the
quantitative assignment and interpretation of the spectra. The rigid,
covalently bound dimer, TIPS-BP1$'$, supports persistent spin coherences at
temperatures far higher than those used in conventional quantum hardware.",2202.09678v1
2022-02-24,Phonon thermal Hall effect in a metallic spin ice,"It has become common knowledge that phonons can generate thermal Hall effect
in a wide variety of materials, although the underlying mechanism is still
controversial. We study longitudinal $\kappa_{xx}$ and transverse $\kappa_{xy}$
thermal conductivity in Pr$_2$Ir$_2$O$_7$, which is a metallic analogue of spin
ice. Despite the presence of mobile charge carriers, we find that both
$\kappa_{xx}$ and $\kappa_{xy}$ are dominated by phonons. A $T/H$ scaling of
$\kappa_{xx}$ unambiguously reveals that longitudinal heat current is
substantially impeded by resonant scattering of phonons on paramagnetic spins.
Upon cooling, the resonant scattering is strongly affected by a development of
spin ice correlation and $\kappa_{xx}$ deviates from the scaling in an
anisotropic way with respect to field directions. Strikingly, a set of the
$\kappa_{xx}$ and $\kappa_{xy}$ data clearly shows that $\kappa_{xy}$
correlates with $\kappa_{xx}$ in its response to magnetic field including a
success of the $T/H$ scaling and its failure at low temperature. This
remarkable correlation provides solid evidence that an indispensable role is
played by spin-phonon scattering not only for hindering the longitudinal heat
conduction, but also for generating the transverse response.",2202.12149v1
2022-03-28,Electron-spin spectral diffusion in an erbium doped crystal at millikelvin temperatures,"Erbium-doped crystals offer a versatile platform for hybrid quantum devices
because they combine magnetically-sensitive electron-spin transitions with
telecom-wavelength optical transitions. At the high doping concentrations
necessary for many quantum applications, however, strong magnetic interactions
of the electron-spin bath lead to excess spectral diffusion and rapid
decoherence. Here we lithographically fabricate a 4.4 GHz superconducting
planar micro-resonator on a $\text{CaWO}_{4}$ crystal doped with Er ions at a
concentration of twenty parts per million relative to Ca. Using the microwave
resonator, we characterize the spectral diffusion processes that limit the
electron-spin coherence of Er ions at millikelvin temperatures by applying 2-
and 3-pulse echo sequences. The coherence time shows a strong temperature
dependence, reaching 1.3 ms at 23 mK for an electron-spin transition of
$^{167}\text{Er}$.",2203.15012v1
2022-06-19,Studying triangle singularity through spin observables,"In this work, we study the spin density matrix element $\rho_{00}$ of the
$\phi$ in the decay $J/\psi \rightarrow \eta \pi \phi$. In previous studies, a
band around 1.4 GeV on the $\pi^0\phi$ distribution in Dalitz plot was reported
by the BESIII Collaboration. This structure may be caused by the production of
a resonance or the triangle singularity mechanism. We find that the predictions
of the spin density matrix elements of the final $\phi$ based on these
mechanisms show distinct features. Thus the measurement of the spin density
matrix elements of the $\phi$ in this reaction may offer an alternative way to
study the triangle singularity and to clarify the reaction mechanisms, i.e.
resonance production or kinematic effects. This work also shows the potential
of spin observables in studying kinematic singularities.",2206.09308v2
2022-07-27,Resonant single-shot CNOT in remote double quantum dot spin qubits,"A critical element towards the realization of scalable quantum processors is
non-local coupling between nodes. Scaling connectivity beyond nearest-neighbor
interactions requires the implementation of a mediating interaction often
termed a 'quantum bus'. Cavity photons have long been used as a bus by the
superconducting qubit community, but it has only recently been demonstrated
that spin-based qubits in double quantum dot architectures can reach the strong
coupling regime and exhibit spin-spin interactions via the exchange of real or
virtual photons. Two-qubit gate operations are predicted in the dispersive
regime where cavity loss plays a less prominent role. In this work we propose a
framework for ac-driven quantum gates, in the context of a CNOT operation,
between two non-local single-spin qubits dispersively coupled to a common mode
of a superconducting resonator. We expect gate times near 150 ns and fidelities
above 90% with existing technology.",2207.13588v1
2023-01-18,Coupling spin defects in hexagonal boron nitride to a microwave cavity,"Optically addressable spin defects in hexagonal boron nitride (hBN) have
become a promising platform for quantum sensing. While sensitivity of these
defects are limited by their interactions with the spin environment in hBN,
inefficient microwave delivery can further reduce their sensitivity. Hare, we
design and fabricate a microwave double arc resonator for efficient
transferring of the microwave field at 3.8 GHz. The spin transitions in the
ground state of VB- are coupled to the frequency of the microwave cavity which
results in enhanced optically detected magnetic resonance (ODMR) contrast. In
addition, the linewidth of the ODMR signal further reduces, achieving a
magnetic field sensitivity as low as 42.4 microtesla per square root of hertz.
Our robust and scalable device engineering is promising for future employment
of spin defects in hBN for quantum sensing.",2301.07304v1
2023-04-11,Anomalous spin textures in a 2D topological superconductor induced by point impurities,"Topological superconductors are foreseen as good candidates for the search of
Majorana zero modes, where they appear as edge states and can be used for
quantum computation. In this context, it becomes necessary to study the
robustness and behavior of electron states in topological superconductors when
a magnetic or non-magnetic impurity is present. We focus on scattering
resonances in the bands and on spin texture to know what the spin behavior of
the electrons in the system will be. We find that the scattering resonances
appear outside the superconducting gap, thus providing evidence of topological
robustness. We also find non-trivial and anisotropic spin textures related to
the Dzyaloshinskii-Moriya interaction. The spin textures show a
Ruderman-Kittel-Kasuya-Yosida interaction governed by Friedel oscillations. We
believe that our results are useful for further studies which consider
many-point-impurity scattering or a more structured impurity potential with a
finite range.",2304.05256v1
2023-05-05,Optically driven spin precession in polariton condensates,"External driving of spinor degrees of freedom by magnetic or optical fields
in quantum systems underpin many applications ranging from nuclear magnetic
resonance to coherent state control in quantum computing. Although spinor
polariton condensates are offering a flexible platform for spinoptronic
applications, strong inter-particle interactions limit their spin coherence.
Here, we introduce an all-optically driven spin precession in microcavity
polariton condensates that eliminates depolarisation, through a radio frequency
modulation of a spatially rotating, asymmetric exciton reservoir that both
confines, and actively replenishes the polariton condensate. We realise several
GHz driven spin precession with a macroscopic spin coherence time that is
limited only by the extraneous to the condensate, frequency drift of the
composite pumping sources. Our observations are supported by mean field
modelling and evidence a driven-dissipative quantum fluidic analogue of the
nuclear magnetic resonance effect.",2305.03782v1
2023-11-20,Bulk photovoltaic effect in antiferromagnet: Role of collective spin dynamics,"Inspired by recent advancements in the bulk photovoltaic effect which can
extend beyond the independent particle approximation (IPA), this study delves
into the influence of collective spin dynamics in an antiferromagnetic on
photocurrent generation using a time domain calculation. In the linear and
photocurrent conductivity spectra, we observe peaks below the bandgap regime,
attributed to the resonant contributions of collective modes, alongside
broadband modifications resulting from off-resonant spin dynamics. Notably, the
emergence of spin dynamics allows various types of photocurrent, which are
absent in the IPA framework. Furthermore, we emphasize the importance of energy
scale proximity between electronic and spin degrees of freedom in enabling
efficient feedback between them. These findings offer new avenues for efficient
energy harvesting and optoelectronic applications.",2311.12212v2
2023-12-15,Axion-like Particle Detection in Alkali-Noble-Gas Haloscopes,"Revealing the essence of dark matter (DM) and dark energy is essential for
understanding our universe. Ultralight (rest energy $<$10 eV) bosonic
particles, including pseudoscalar axions and axion-like particles (ALPs) have
emerged among leading candidates to explain the composition of DM and searching
for them has become an important part of precision-measurement science.
Ultrahigh-sensitivity alkali-noble-gas based comagnetometers and magnetometers
are being used as powerful haloscopes, i.e., devices designed to search for DM
present in the galactic halo. A broad variety of such devices include
clock-comparison comagnetometers, self-compensating comagnetometers,
hybrid-spin-resonance magnetometer, spin-exchange-relaxation-free
magnetometers, nuclear magnetic-resonance magnetometers, Floquet magnetometers,
masers, as well as devices like the cosmic axion spin-precession experiment
(CASPEr) using liquid $^{129}$Xe, prepolarized via spin-exchange optical
pumping with rubidium atoms. The combination of alkali metal and noble gas
allows one to take the best advantage of the complementary properties of the
two spin systems. This review summarizes the operational principles,
experimental setups and the successful explorations of new physics using these
haloscopes. Additionally, some limiting factors are pointed out for further
improvement.",2312.09491v2
1995-12-05,Phase Diagram for Charge Density Waves in a Magnetic Field,"The influence of an external magnetic field on a quasi one-dimensional system
with a charge density wave (CDW) instability is treated within the random phase
approximation which includes both CDW and spin density wave correlations. We
show that the CDW is sensitive to both orbital and Pauli effects of the field.
In the case of perfect nesting, the critical temperature decreases monotonously
with the field, and the wave vector of the instability starts to shift above
some critical value of magnetic field. Depending on the ratio between the spin
and charge coupling constants and on the direction of the applied magnetic
field, the wave vector shift is either parallel ($CDW_x$ order) or
perpendicular ($CDW_y$ order) to the most conducting direction. The $CDW_x$
order is a field dependent linear combination of the charge and spin density
waves and is sensible only to the Pauli effect. The wave vector shift in
$CDW_y$ depends on the interchain coupling, but the critical temperature does
not. This order is affected by the confinement of the electronic orbits. By
increasing the relative strength of the orbital effect with respect to the
Pauli effect, one can destroy the $CDW_y$, establishing either a $CDW_x$, or a
$CDW_0$ (corresponding to perfect nesting wave vector). We also show that by
increasing the imperfect nesting parameter, one passes from the regime where
the critical temperature decreases with the field to the regime where it is
initially enhanced by the orbital effect and eventually suppressed by the Pauli
effect. For a bad nesting, the quantized phases of the field-induced CDW
appear.",9512033v1
2019-03-22,Unidirectional Maxwellian Spin Waves,"We develop a unified perspective of unidirectional topological edge waves in
non-reciprocal media. We focus on the inherent role of photonic spin in
non-reciprocal gyroelectric media, ie. magnetized metals or magnetized
insulators. We first review the concept of a Maxwell Hamiltonian in
non-reciprocal media, which immediately reveals that the gyrotropic coefficient
behaves as a photon mass in two dimensions. Similar to the Dirac mass, this
photonic mass opens bandgaps in the energy dispersion of bulk propagating
waves. Within these bulk photonic bandgaps, three distinct classes of
Maxwellian edge waves exist - each arising from subtle differences in boundary
conditions. On one hand, the edge wave solutions are rigorous photonic analogs
of Jackiw-Rebbi electronic edge states. On the other hand, for the exact same
system, they can be high frequency photonic counterparts of the integer quantum
Hall effect, familiar at zero frequency. Our Hamiltonian approach also predicts
the existence of a third distinct class of Maxwellian edge wave exhibiting
topological protection. The Maxwellian edge state in this unique
\textit{quantum gyroelectric phase of matter} necessarily requires a sign
change in gyrotropy arising from non-locality (spatial dispersion). A signature
property of these topological electromagnetic edge states is that they are
oblivious to the contacting medium, ie. they occur at the interface of the
quantum gyroelectric phase and any medium (even vacuum). Furthermore, the
Maxwellian spin waves exhibit photonic spin-1 quantization in exact analogy
with their supersymmetric spin-\sfrac{1}{2} counterparts. The goal of this
paper is to discuss these three foundational classes of edge waves in a unified
perspective while providing in-depth derivations, taking into account
non-locality and various boundary conditions.",1903.09278v1
1993-02-12,Possible Realization of Odd Frequency Pairing in Heavy Fermion Compounds,"Using Majorana Fermions to represent spins we re-examine the Kondo Lattice
model for heavy fermions. The simplest decoupling procedure provides a
realization of odd frequency superconductivity, with resonant pairing and
surfaces of gap zeros. Spin and charge coherence factors vanish linearly with
the energy on the Fermi surface, predicting a linear specific heat, but a $T^3$
NMR relaxation rate. Possible application to heavy fermions is suggested.",9302018v1
2001-04-24,Raman cross section of spin ladders,"We demonstrate that a two-triplet resonance strongly renormalizes the Raman
spectrum of two-leg spin ladders and moreover suggest this to be the origin of
the asymmetry of the magnetic Raman continuum observed in CaV2O5.",0104465v1
2002-12-06,Nuclear Spin Superradiance,"The review of experimental and main theoretical works on the phenomenon of
nuclear spin superradiance is given. The content includes: 1. Introduction, 2.
Experimental Observation, 3. Basic Model, 4. Evolution Equations, 5. Nyquist
Noise, 6. Incoherent Stage, 7. Transient Superradiance, 8. Pulsing
Superradiance, 9. Hyperfine Interactions, 10. Radiation Intensity, 11.
Applications, 12. References",0212139v1
2005-01-06,Spin dependent transport in organic light-emitting diodes,"Electrically Detected Magnetic Resonance (EDMR) was used to study a series of
multilayer organic devices based on aluminum (III) 8-hydroxyquinoline. These
devices were designed to identify the micoscopic origin of different spin
dependent process, i.e. hopping and exciton formation. EDMR is demonstrated to
probe molecular orbitals of charge, and thus indirectly explore interfaces,
exciton formation, charge accumalation and electric fields in operating organic
based devices.",0501122v1
2005-03-01,Low Dimensional Lattice Diffusion in Solids Investigated by Nuclear Spin Echo Measurements,"Lattice diffusion and internal local magnetic field gradients in solids are
investigated by numerical simulation of nuclear mangetic resonance(NMR) spin
echo experiments. The Fourier-spectrum method is employed in order to solve the
Bloch-Torrey equation with arbitrary magnetic field gradients in one- and
two-dimensional lattice restrictions.",0503003v1
1995-11-11,Multipole analysis of spin observables in vector meson photoproduction,"A multipole analysis of vector meson photoproduction is formulated as a
generalization of the pseudoscalar meson case. Expansion of spin observables in
the multipole basis and behavior of these observables near threshold and
resonances are examined.",9511013v1
2001-05-22,Spin structure of the Delta(1232) and inelastic Compton scattering,"Radiative transitions gamma + Delta(1232) -> N^* are discussed in the
nonrelativistic quark model with spin-orbit corrections for the 70-plet L^P=1^-
nucleon resonances N^*. The reaction gamma + N -> gamma + Delta is considered
as a tool to measure some of these transitions. A particular sensitivity to
photoexcitations of S_{11}(1535), D_{13}(1700), and D_{15}(1675) is predicted.",0105056v1
1999-09-29,Light-induced conversion of nuclear spin isomers of molecules,"We report on a new phenomenon of molecular nuclear spin isomers conversion in
the field of resonant laser radiation. It is based on the isomer-selective
optical excitation and the difference of conversion rates for excited and
unexcited molecules. We expect the considerable magnitude of the effect for all
molecules which absorb the radiation of existing lasers.",9909056v1
2000-11-18,New access to very weak interactions in molecules,"It is predicted that nuclear spin conversion in molecules can be efficiently
controlled by strong laser radiation resonant to rovibrational molecular
transition. The phenomenon can be used for substantial enrichment of spin
isomers, or for detection of very weak (10-100 Hz) interactions in molecules.",0011043v1
1998-02-03,Generalized Quantum Control-Not Gate in Two-Spin Ising System,"The physical implementation of the quantum Control-Not gate for a two-spin
system is investigated numerically. The concept of a generalized quantum
Control-Not gate, with arbitrary phase shift, is introduced. It is shown that a
resonant $\pi$-pulse provides a simple example of a generalized quantum
Control-Not gate.",9802013v1
2008-09-12,Quantum spin liquids,"These notes are an introduction to a few selected theoretical ideas in the
field of quantum spin liquids: classical zero modes and breakdown of the 1/S
expansion, the Lieb-Schultz-Mattis-Hastings theorem and Oshikawa's argument,
the short-ranged resonating valence-bond picture, large-N limit (Schwinger
bosons) and Z_2 gauge theory.",0809.2257v1
2008-09-26,Laser Induced Selective Alignment of Water Spin Isomers,"We consider laser alignment of ortho and para spin isomers of water molecules
by using strong and short off-resonance laser pulses. A single pulse is found
to create a distinct transient alignment and antialignment of the isomeric
species. We suggest selective alignment of one isomeric species (leaving the
other species randomly aligned) by a pair of two laser pulses.",0809.4626v1
2019-03-21,Spin relaxation in fluorinated single and bilayer graphene,"We present a joint experiment-theory study on the role of fluorine adatoms in
spin and momentum scattering of charge carriers in dilute fluorinated graphene
and bilayer graphene. The experimental spin-flip and momentum scattering rates
and their dependence on the density of fluorine and carrier doping are obtained
through weak localization and conductivity measurements, respectively, and
suggest the role of fluorine as resonant magnetic impurities. For the estimated
fluorine concentration of a few 100 ppm, the observed spin lifetimes are in the
range of 1-10\,ps. Theoretically, we established tight-binding electronic
structures of fluorinated graphene and bilayer graphene by fitting to density
functional supercell calculations and performed a comprehensive analysis of the
spin-flip and momentum scattering rates within the same devices, aiming to
develop a consistent description of both scattering channels. We find that
resonant scattering in graphene is very sensitive to the precise position of
the resonance level, as well as to the magnitude of the exchange coupling
between itinerant carriers and localized spins. The experimental data point to
the presence of weak spin-flip scatterers that, at the same time, relax the
electron momentum strongly, nearly preserving the electron-hole symmetry. Such
scatterers would exhibit resonance energies much closer to the neutrality point
than what density functional theory predicts in the dilute limit. The inclusion
of a magnetic moment on fluorine adatoms allowed us to qualitatively capture
the carrier density dependence of the experimental rates but predicts a greater
(weaker) spin (momentum) relaxation rate than the measurements. We discuss
possible scenarios that may be responsible for the discrepancies. Our
systematic study exposes the complexities involved in accurately capturing the
behavior of adatoms on graphene.",1903.08973v1
2007-03-29,Nucleon resonances in πN scattering up to energies \sqrt(s) < 2.0 GeV,"A meson-exchange model for pion-nucleon scattering was previously constructed
using a three-dimensional reduction scheme of the Bethe-Salpeter equation for a
model Lagrangian involving \pi, \eta, N, \Delta, \rho, and \sigma fields. We
thereby extend our previous work by including the \eta N channel and all the
\pi N resonances with masses ~ 2 GeV, up to the F waves. The effects of the
\pi\pi N channels are taken into account by introducing an effective width in
the resonance propagators. The extended model gives an excellent fit to both
\pi N phase shifts and inelasticity parameters in all channels up to the F
waves and for energies below 2 GeV. We present a new scheme to extract the
properties of overlapping resonances. The predicted values for the resonance
masses and widths as well as resonance pole positions and residues are compared
to the listing of the Particle Data Group.",0703096v2
2016-08-31,Importance of transient resonances in extreme-mass-ratio inspirals,"The inspiral of stellar-mass compact objects, like neutron stars or
stellar-mass black holes, into supermassive black holes provides a wealth of
information about the strong gravitational-field regime via the emission of
gravitational waves. In order to detect and analyse these signals, accurate
waveform templates which include the effects of the compact object's
gravitational self-force are required. For computational efficiency, adiabatic
templates are often used. These accurately reproduce orbit-averaged
trajectories arising from the first-order self-force, but neglect other
effects, such as transient resonances, where the radial and poloidal
fundamental frequencies become commensurate. During such resonances the flux of
gravitational waves can be diminished or enhanced, leading to a shift in the
compact object's trajectory and the phase of the waveform. We present an
evolution scheme for studying the effects of transient resonances and apply
this to an astrophysically motivated population. We find that a large
proportion of systems encounter a low-order resonance in the later stages of
inspiral; however, the resulting effect on signal-to-noise recovery is small as
a consequence of the low eccentricity of the inspirals. Neglecting the effects
of transient resonances leads to a loss of 4% of detectable signals.",1608.08951v2
2018-07-15,Effects of Distributed Roughness on Crossflow Instability through Generalized Resonance Mechanisms,"Experiments have shown that micron-sized distributed surface roughness can
significantly promote transition in a three-dimensional boundary layer
dominated by crossflow insta- bility. This sensitive effect has not yet been
fully explained physically and mathematically. Unlike past researches focusing
on the receptivity of the boundary layer to surface roughness, or on the local
stability of the modified mean flow, this paper seeks possible inherent
mechanisms by investigating the effects of distributed surface roughness on
crossflow instability through resonant interactions with eigenmodes. A key
observation is that the perturbation induced by roughness with specific
wavenumbers can interact with two eigenmodes (travelling and stationary
vortices) through triadic resonance, or interact with one eigenmode (stationary
vortices) through Bragg scattering. Unlike the usual triadic resonance of
neutral, or nearly neutral, eigenmodes, the present triadic resonance can take
place among modes with O(1) growth rates, provided that these are equal; unlike
the usual Bragg scattering involving neutral waves, crossflow stationary
vortices can also be unstable. For these amplifying waves, the generalized
triadic resonance and Bragg scattering are put forward, and the resulting
corrections to the growth rates are derived by a multiple-scale method. The
analysis is extended to the case where up to four crossflow vortices interact
with each other in the presence of suitable roughness components. The numerical
results for Falkner-Skan-Cooke boundary layers show that roughness with a small
height (a few percent of the local boundary-layer thickness) can change growth
rates substantially (by a more-or-less O(1) amount)....",1807.05468v1
2017-09-22,Optical Wireless Information Transfer with Nonlinear Micromechanical Resonators,"Wireless transfer of information is the basis of modern communication. It
includes cellular, WiFi, Bluetooth and GPS systems, all of which use
electromagnetic radio waves with frequencies ranging from typically 100 MHz to
a few GHz. However, several long-standing challenges with standard radio-wave
wireless transmission still exist, including keeping secure transmission of
data from potential compromise. Here, we demonstrate wireless information
transfer using a line-of-sight optical architecture with a micromechanical
element. In this fundamentally new approach, a laser beam encoded with
information impinges on a nonlinear micromechanical resonator located a
distance from the laser. The force generated by the radiation pressure of the
laser light on the nonlinear micromechanical resonator produces a sideband
modulation signal, which carries the precise information encoded in the subtle
changes in the radiation pressure. Using this, we demonstrate data and image
transfer with one hundred percent fidelity with a single 96 micron by 270
micron silicon resonator element in an optical frequency band. This mechanical
approach relies only on the momentum of the incident photons and is therefore
able to use any portion of the optical frequency banda band that is 10,000
times wider than the radio frequency band. Our line-of-sight architecture using
highly scalable micromechanical resonators offers new possibilities in wireless
communication. Due to their small size, these resonators can be easily arrayed
while maintaining a small form factor to provide redundancy and parallelism.",1710.00664v1
2019-01-25,Phononic band structure engineering for high-Q gigahertz surface acoustic wave resonators on lithium niobate,"Phonons at gigahertz frequencies interact with electrons, photons, and atomic
systems in solids, and therefore have extensive applications in signal
processing, sensing, and quantum technologies. Surface acoustic wave (SAW)
resonators that confine surface phonons can play a crucial role in such
integrated phononic systems due to small mode size, low dissipation, and
efficient electrical transduction. To date, it has been challenging to achieve
high quality (Q) factor and small phonon mode size for SAW resonators at
gigahertz frequencies. Here, we present a methodology to design compact high-Q
SAW resonators on lithium niobate operating at gigahertz frequencies. We
experimentally verify out designs and demonstrate Q factors in excess of
$2\times10^4$ at room temperature ($6\times10^4$ at 4 Kelvin) and mode area as
low as $1.87 \lambda^2$. This is achieved by phononic band structure
engineering, which provides high confinement with low mechanical loss. The
frequency-Q products (fQ) of our SAW resonators are greater than $10^{13}$.
These high-fQ and small mode size SAW resonators could enable applications in
quantum phononics and integrated hybrid systems with phonons, photons, and
solid-state qubits.",1901.09080v2
2019-07-23,Hybrid Integrated Photonics Using Bulk Acoustic Resonators,"Microwave frequency acousto-optic modulation is realized by exciting high
overtone bulk acoustic wave resonances (HBAR resonances) in the photonic stack.
These confined mechanical stress waves transmit exhibit vertically
transmitting, high quality factor (Q) acoustic Fabry Perot resonances that
extend into the Gigahertz domain, and offer stress-optical interaction with the
optical modes of the microresonator. Although HBAR are ubiquitously used in
modern communication, and often exploited in superconducting circuits, this is
the first time they have been incorporated on a photonic circuit based chip.
The electro-acousto-optical interaction observed within the optical modes
exhibits high actuation linearity, low actuation power and negligible
crosstalk. Using the electro-acousto-optic interaction, fast optical resonance
tuning is achieved with sub-nanosecond transduction time. By removing the
silicon backreflection, broadband acoustic modulation at 4.1 and 8.7 GHz is
realized with a 3 dB bandwidth of 250 MHz each. The novel hybrid HBAR
nanophotonic platform demonstrated here, allowing on chip integration of
micron-scale acoustic and photonic resonators, can find immediate applications
in tunable microwave photonics, high bandwidth soliton microcomb stabilization,
compact opto-electronic oscillators, and in microwave to optical conversion
schemes. Moreover the hybrid platform allows implementation of momentum
biasing, which allows realization of on chip non-reciprocal devices such as
isolators or circulators and topological photonic bandstructures.",1907.10177v1
2021-12-20,A place for two-dimensional plasmonics in electromagnetic wave detection,"Plasmons in two-dimensional electron systems (2DES) feature ultra-strong
confinement and are expected to efficiently mediate the interactions between
light and charge carriers. Despite these expectations, the electromagnetic
detectors exploiting 2d plasmon resonance have been so far inferior to their
non-resonant counterparts. Here, we theoretically analyse the origin of these
failures, and suggest a proper niche for 2d plasmonics in electromagnetic wave
detection. We find that a confined 2DES supporting plasmon resonance has an
upper limit of absorption cross-section, which is identical to that of simple
metallic dipole antenna. Small size of plasmonic resonators implies their weak
dipole moments and impeded coupling to free-space radiation. Achieving the
'dipole limit' of absorption cross-section in isolated 2DES is possible either
at unrealistically long carrier momentum relaxation times, or at resonant
frequencies below units of terahertz. We further show that amendment of even
small metal contacts to 2DES promotes the coupling and reduces the fundamental
mode frequency. The contacted resonators can still have deep-subwavelength
size. They can be merged into compact arrays of detectors, where signals from
elements tuned to different frequencies are summed up. Such arrays may find
applications in multi-channel wireless communications, hyper-spectral imaging,
and energy harvesting.",2112.10475v1
2022-01-17,Phase-resolved visualization of radio-frequency standing waves in superconducting spiral resonator for metamaterial applications,"Superconducting microcircuits and metamaterials are promising candidates for
use in new generation cryogenic electronics. Their functionality is largely
justified by the macroscopic distribution of electromagnetic fields in arranged
unit cells, rather than by the microscopic properties of composite materials.
We present a new method for visualizing the spatial structure of penetrating
microwaves with microscopic resolution in planar superconducting macroscopic
resonators as the most important circuit-forming elements of modern
microelectronics. This method uses a low-temperature laser scanning microscope
that examines the phase (i.e., direction) and amplitude of local
radio-frequency currents versus the two-dimensional coordinates of the
superconducting resonant structure under test. Phase-sensitive contrast is
achieved by synchronizing the intensity-modulated laser radiation with the
resonant harmonics of the microwave signal passing through the sample. In this
case, the laser-beam-induced loss in the illuminated area will strongly depend
on the local phase difference between the RF carrier signal and the spatially
temporal structure of the focused laser oscillation. This approach eliminates
the hardware limitations of the existing technique of radio-frequency
microscopy and brings the phase-sensitive demodulation mode to the level
necessary for studying the physics of superconducting metamaterials. The
advantage of the presented method over the previous method of RF laser scanning
microscopy is demonstrated by the example of the formation of standing waves in
a spiral superconducting Archimedean resonator up to the 38th eigenmode
resonance.",2201.06660v1
2024-02-22,Combinatorial split-ring and spiral meta-resonator for efficient magnon-photon coupling,"Developing hybrid materials and structures for electromagnetic wave
engineering has been a promising route towards novel functionalities and
tunabilities in many modern applications and perspectives in new quantum
technologies. Despite its established success in engineering optical light and
terahertz waves, the implementation of meta-resonators operating at the
microwave band is still emerging, especially those that allow for on-chip
integration and size miniaturization, which has turned out crucial to
developing hybrid quantum systems at the microwave band. In this work, we
present a microwave meta-resonator consisting of split-ring and and spiral
resonators, and implement it to the investigation of photon-magnon coupling for
hybrid magnonic applications. We observe broadened bandwidth to the split ring
modes augmented by the additional spiral resonator, and, by coupling the modes
to a magnetic sample, the resultant photon-magnon coupling can be significantly
enhanced to more than ten-fold. Our work suggests that combinatorial, hybrid
microwave resonators may be a promising approach towards future development and
implementation of photon-magnon coupling in hybrid magnonic systems.",2402.15535v2
2021-01-12,The complex interplay between tidal inertial waves and zonal flows in differentially rotating stellar and planetary convective regions I. Free waves,"Quantifying tidal interactions in close-in two-body systems is of prime
interest since they have a crucial impact on the architecture and on the
rotational history of the bodies. Various studies have shown that the
dissipation of tides in either body is very sensitive to its structure and to
its dynamics, like differential rotation which exists in the outer convective
enveloppe of solar-like stars and giant gaseous planets. In particular, tidal
waves may strongly interact with zonal flows at the so-called corotation
resonances, where the wave's Doppler-shifted frequency cancels out. We aim to
provide a deep physical understanding of the dynamics of tidal inertial waves
at corotation resonances, in the presence of differential rotation profiles
typical of low-mass stars and giant planets. By developping an inclined
shearing box, we investigate the propagation and the transmission of free
inertial waves at corotation, and more generally at critical levels, which are
singularities in the governing wave differential equation. Through the
construction of an invariant called the wave action flux, we identify different
regimes of wave transmission at critical levels, which are confirmed with a
one-dimensional three-layer numerical model. We find that inertial waves can be
either fully transmitted, strongly damped, or even amplified after crossing a
critical level. The occurrence of these regimes depends on the assumed profile
of differential rotation, on the nature as well as the latitude of the critical
level, and on wave parameters such as the inertial frequency and the
longitudinal and vertical wavenumbers. Waves can thus either deposit their
action flux to the fluid when damped at critical levels, or they can extract
action flux to the fluid when amplified at critical levels. Both situations
could lead to significant angular momentum exchange between the tidally
interacting bodies.",2101.04656v1
1994-11-01,Cyclotron resonance lineshape in a Wigner crystal,"The cyclotron resonance absorption spectrum in a Wigner crystal is
calculated. Effects of spin-splitting are modelled by substitutional disorder,
and calculated in the coherent potential approximation. Due to the increasing
strength of the dipole-dipole interaction, the results show a crossover from a
double-peak spectrum at small filling factors to a single-peak spectrum at
filling factors $\agt 1/6$. Radiation damping and magnetophonon scattering can
also influence the cyclotron resonance. The results are in very good agreement
with experiments.",9411003v2
1999-11-09,Cooper Pairing in Ultracold K-40 Using Feshbach Resonances,"We point out that the fermionic isotope K-40 is a likely candidate for the
formation of Cooper pairs in an ultracold atomic gas. Specifically, in an
optical trap that simultaneously traps the spin states |9/2,-9/2> and
|9/2,-7/2>, there exists a broad magnetic field Feshbach resonance at B = 196
gauss that can provide the required strong attractive interaction between
atoms. An additional resonance, at B = 191 gauss, could generate p-wave pairing
between identical |9/2,-7/2> atoms. A Cooper-paired degenerate Fermi gas could
thus be constructed with existing ultracold atom technology.",9911132v1
2000-09-22,Resonant tunneling through zero-dimensional impurity states: Effects of a finite temperature,"We have performed temperature dependent tunneling experiments through a
single impurity in an asymmetric vertical double barrier tunneling structure.
In particular in the charging direction we observe at zero magnetic field a
clear shift in the onset voltage of the resonant tunneling current through the
impurity. With a magnetic field applied the shift starts to disappear. The
experimental observations are explained in terms of resonant tunneling through
a spin degenerate impurity level.",0009349v1
2001-10-22,What the resonance peak cannot do,"In certain cuprates, a spin 1 resonance mode is prominent in the magnetic
structure measured by neutron scattering. It has been proposed that this mode
is responsible for significant features seen in other spectroscopies, such as
photoemission and optical absorption, which are sensitive to the charge
dynamics, and even that this mode is the boson responsibile for ``mediating''
the superconducting pairing. We show that its small (measured) intensity and
weak coupling to electron-hole pairs (as deduced from the measured lifetime)
disqualifies the resonant mode from either proposed role.",0110478v1
2002-09-04,Tuning p-wave interactions in an ultracold Fermi gas of atoms,"We have measured a p-wave Feshbach resonance in a single-component, ultracold
Fermi gas of potassium atoms. We have used this resonance to enhance the
normally suppressed p-wave collision cross-section to values larger than the
background s-wave cross-section between potassium atoms in different
spin-states. In addition to the modification of two-body elastic processes, the
resonance dramatically enhances three-body inelastic collisional loss.",0209071v1
2003-04-08,Exploiting environmental resonances to enhance qubit quality factors,"We discuss dephasing times for a two-level system (including bias) coupled to
a damped harmonic oscillator. This system is realized in measurements on
solid-state Josephson qubits. It can be mapped to a spin-boson model with a
spectral function with an approximately Lorentzian resonance. We diagonalize
the model by means of infinitesimal unitary transformations (flow equations),
and calculate correlation functions, dephasing rates, and qubit quality
factors. We find that these depend strongly on the environmental resonance
frequency $\Omega$; in particular, quality factors can be enhanced
significantly by tuning $\Omega$ to lie below the qubit frequency $\Delta$.",0304177v1
2004-08-24,Inelastic light scattering and the off-resonance approximation,"Inelastic (Raman) light scattering intensities for a 42-electron quantum dot
under off-resonance conditions and in different spin and angular momentum
channels are computed in order to test whether final collective states become
the dominant peaks in the process. The results of the calculations set a limit
to the spread use of the off-resonant approximation for the theoretical
description of Raman processes.",0408510v1
2004-09-04,Pure nuclear quadrupole resonance determination of the electric field gradient asymmetry for broad lines (and application to YBa2Cu3O7),"We present an angle dependent nuclear quadrupole resonance (ADNQR) method to
determine the electric field gradient asymmetry parameter eta in systems where
the resonance line is so broad that the radio frequency field can excite only a
portion of the nuclear spins. In this situation the recently developed
spectroscopic methods are not applicable. ADNQR is useful for single crystals
and oriented powders, and, for small eta determines eta^4. Therefore, it can be
used to evaluate fluctuations in eta due to inhomogeneities. We demonstrate the
application of ADNQR experimentally to oriented superconducting YBa2Cu3O7
powder.",0409101v1
2005-05-18,Resonant tunneling magnetoresistance in epitaxial metal-semiconductor heterostructures,"We report on resonant tunneling magnetoresistance via localized states
through a ZnSe semiconducting barrier which can reverse the sign of the
effective spin polarization of tunneling electrons. Experiments performed on
Fe/ZnSe/Fe planar junctions have shown that positive, negative or even its
sign-reversible magnetoresistance can be obtained, depending on the bias
voltage, the energy of localized states in the ZnSe barrier and spatial
symmetry. The averaging of conduction over all localized states in a junction
under resonant condition is strongly detrimental to the magnetoresistance.",0505432v1
2005-12-31,Trapped Fermions across a Feshbach resonance with population imbalance,"We investigate the phase separation of resonantly interacting fermions in a
trap with imbalanced spin populations, both at zero and at finite temperatures.
We directly minimize the thermodynamical potential under the local density
approximation instead of using the gap equation, as the latter may give
unstable solutions. On the BEC side of the resonance, one may cross three
different phases from the trap center to the edge; while on the BCS side or at
resonance, typically only two phases show up. We compare our results with the
recent experiment, and the agreement is remarkable.",0601006v2
2006-06-20,Resonant Tunneling Magneto Resistance in Coupled Quantum Wells,"A three barrier resonant tunneling structure in which the two quantum wells
are formed by a dilute magnetic semiconductor material (ZnMnSe) with a giant
Zeeman splitting of the conduction band is theoretically investigated.
Self-consistent numerical simulations of the structure predict giant
magnetocurrent in the resonant bias regime as well as significant current spin
polarization for a considerable range of applied biases.",0606531v2
1999-09-28,Resonances and higher twist in polarized lepton-nucleon scattering,"We present a detailed analysis of resonance contributions in the context of
higher twist effects in the moments of the proton spin structure function g_1.
For each of these moments, it is found that there exists a characteristic Q^2
region in which (perturbative) higher twist corrections coexist with
(non-perturbative) resonance contribution of comparable magnitude.",9909524v1
1999-10-18,Chiral Symmetry Realization for Even- and Odd-parity Baryon Resonances,"Baryon resonances with even and odd parity are collectively investigated from
the viewpoint of chiral symmetry(ChS). We propose a quartet scheme where
Delta's and N^*'s with even and odd parity form a chiral multiplet. This scheme
gives parameter-free constraints on the baryon masses in the quartet, which are
consistent with observed masses with spin 1/2, 3/2, 5/2. The scheme also gives
selection rules in the one-pion decay: The absence of the parity non-changing
decay N(1720) -> pi Delta(1232) is a typical example which should be confirmed
experimentally to unravel the role of ChS in baryon resonances.",9910375v1
2001-09-07,The Nucleon Structure in the Resonance Region,"Recent results on inclusive and exclusive electroproduction experiments at
Jefferson Lab are discussed. They include measurements of the spin responses
for protons and neutrons in and above the resonance region, exclusive single
and double pion production to measure resonance transition multipoles, and
searches for predicted yet unobserved quark model states. A brief outlook into
the new domain of generalized parton distribution is given as well.",0109004v2
1996-06-20,Pseudoscalar meson photoproduction: from known to undiscovered resonances,"The role of dynamics in spin observables for pseudoscalar meson
photoproduction is investigated using a density matrix approach in a multipole
truncated framework. Extraction of novel rules for $\gamma p \rightarrow \pi^+
n,~ K^+ \Lambda$ and $\eta p$ reactions based on resonance dominance, and on
other broad and reasonable dynamical assumptions, are discussed. Observables
that are particularly sensitive to missing nucleonic resonances predicted by
quark-based approaches, are singled out.",9606042v1
2000-10-18,The GDH sum rule for the Delta isobar: A possible anomaly?,"The GDH sum rule is discussed for the Delta(1232) resonance. It is shown that
apart from ordinary excitations to higher-energy states, the sum rule contains
a large negative contribution due to de-excitation into the nucleon state.
Therefore, a fulfillment of the sum rule assumes a strong coupling of Delta^+
and Delta^0 to resonances of spin 5/2 and higher. Calculations performed in
quark models suggest that D15(1675) may be such a resonance. However, its
strength is found to be not sufficient for bringing the GDH sum rule to a
theoretically expected positive magnitude.",0010060v1
2002-05-19,Effective Lagrangian approach to the omega meson photoproduction near threshold,"We apply the effective Lagrangian approach to investigate the role of the
nucleon resonances in $\omega$ meson photoproduction at energies near the
threshold. The resonant amplitudes are calculated from effective Lagrangians
with the gamma NN* and omega NN* coupling constants fixed by the empirical
helicity amplitudes and the vector meson dominance model. The contributions
from the nucleon resonances are found to be significant in changing the
differential cross sections in a wide interval of t and various spin
observables.",0205052v1
2007-03-14,Nuclear Giant Resonances and Linear Response,"We search for nonlinear effects in nuclear giant resonances (GRs), in
particular the isovector dipole and the isoscalar quadrupole modes. To that
end, we employ a spectral analysis of time-dependent Hartree-Fock (TDHF)
dynamics using Skyrme forces. Based on TDHF calculations over a wide range of
excitation amplitudes, we explore the collectivity and degree of harmonic
motion in these modes. Both GR modes turn out to be highly harmonic in heavy
nuclei from A=100 on. There is no trace of a transition to irregular motion and
multiple resonances are predicted. Slight anharmonicities are seen for light
nuclei, particularly for $^{16}$O. These are mainly caused by the spin-orbit
splitting.",0703044v1
2006-08-22,Fabrication of alignment structures for a fiber resonator by use of deep-ultraviolet lithography,"We present a novel method to mount and align an optical-fiber-based resonator
on the flat surface of an atom chip with ultrahigh precision. The structures
for mounting a pair of fibers, which constitute the fiber resonator, are
produced by a spin-coated SU-8 photoresist technique by use of deep-UV
lithography. The design and production of the SU-8 structures are discussed.
  From the measured finesses we calculate the coupling loss of the SU-8
structures acting as a kind of fiber splice to be smaller than 0.013 dB.",0608216v1
2008-03-12,Analysis of angular distributions in gamma N \to pi0 eta N,"Angular distributions in the final state of pi0-eta photoproduction on
nucleons are considered. As a formal base the familiar isobar model is used in
which the (pi0 eta N) state is a product of the resonance decay into
eta-Delta(1232) and pi-S_{11}(1535) channels. One of the principal assumptions
used is that in the actual energy region the reaction is dominated by a single
resonance state. The developed formalism can serve as a tool for testing spin
and parity of that resonance.",0803.1755v1
2008-03-20,Exotic decay modes of the nucleon resonance $N^*(1535)$ and the $θ^+$ problem,"Baryon resonance state with strangeness $S = +1$ observed in systems $p K^0$
and $n K^+$ is interpreted as a result of the decay $N^{*+} \to p \eta$ of the
well-known resonance $N^*(1535)$ (with spin-parity $j^P = {1/2}^-$ and mass $m
\approx 1.54$ GeV) and the subsequent oscillation $\eta \rightleftarrows K^0$.
It is argued that the latter is noticeably enhanced by the neighbourhood of the
$\eta$ and $K^0$ levels and the gluon exchanges of the ""penguin"" form.",0803.2936v1
2008-07-15,Excited-state spectroscopy of single NV defects in diamond using optically detected magnetic resonance,"Using pulsed optically detected magnetic resonance techniques, we directly
probe electron-spin resonance transitions in the excited-state of single
Nitrogen-Vacancy color centers in diamond. Unambiguous assignment of excited
state fine structure is made, based on changes of NV defect photoluminescence
lifetime. This study provides significant insight into the structure of the
emitting 3E excited state, which is invaluable for the development of
diamond-based quantum information processing.",0807.2379v2
2008-10-27,Alternating current driven instability in magnetic junctions,"An effect is considered of alternating (high-frequency) current on the
spin-valve type magnetic junction configuration. The stability with respect to
small fluctuations is investigated in the macrospin approximation. When the
current frequency is close to the eigenfrequency (precession frequency) of the
free layer, parametric resonance occurs. Both collinear configurations,
antiparallel and parallel ones, can become unstable under resonance conditions.
The antiparallel configuration can become unstable under non-resonant
conditions, also. The threshold current density amplitude is of the order of
the dc current density switching the magnetic junction.",0810.4753v1
2009-06-22,Kondo resonance narrowing in d- and f-electron systems,"By developing a simple scaling theory for the effect of Hund's interactions
on the Kondo effect, we show how an exponential narrowing of the Kondo
resonance develops in magnetic ions with large Hund's interaction. Our theory
predicts an exponential reduction of the Kondo temperature with spin S of the
Hund's coupled moment, a little-known effect first observed in d-electron
alloys in the 1960's, and more recently encountered in numerical calculations
on multi-band Hubbard models with Hund's interactions. We discuss the
consequences of Kondo resonance narrowing for the Mott transition in d-band
materials, particularly iron pnictides, and the narrow ESR linewidth recently
observed in ferromagnetically correlated f-electron materials.",0906.4107v1
2009-07-09,A Tuneable Few Electron Triple Quantum Dot,"In this paper we report on a tuneable few electron lateral triple quantum dot
design. The quantum dot potentials are arranged in series. The device is aimed
at studies of triple quantum dot properties where knowing the exact number of
electrons is important as well as quantum information applications involving
electron spin qubits. We demonstrate tuning strategies for achieving required
resonant conditions such as quadruple points where all three quantum dots are
on resonance. We find that in such a device resonant conditions at specific
configurations are accompanied by novel charge transfer behaviour.",0907.1322v1
2009-07-29,Pinning mode resonance of a Skyrme crystal near Landau level filling factor $ν$=1,"Microwave pinning-mode resonances found around integer quantum Hall effects,
are a signature of crystallized quasiparticles or holes. Application of
in-plane magnetic field to these crystals, increasing the Zeeman energy, has
negligible effect on the resonances just below Landau level filling $\nu=2$,
but increases the pinning frequencies near $\nu=1$, particularly for smaller
quasiparticle/hole densities. The charge dynamics near $\nu=1$, characteristic
of a crystal order, are affected by spin, in a manner consistent with a Skyrme
crystal.",0907.5218v1
2010-02-26,Controlled generation of field squeezing with cold atomic clouds coupled to a superconducting transmission line resonator,"We propose an efficient method for controlled generation of field squeezing
with cold atomic clouds trapped close to a superconducting transmission line
resonator. It is shown that, based on the coherent strong magnetic coupling
between the collective atomic spins and microwave fields in the transmission
line resonator, two-mode or single mode field squeezed states can be generated
through coherent control on the dynamics of the system. The degree of squeezing
and preparing time can be directly controlled through tuning the external
classical fields. This protocol may offer a promising platform for implementing
scalable on-chip quantum information processing with continuous variables.",1002.4953v1
2010-06-05,Molecular structure of highly-excited resonant states in $^{24}$Mg and the corresponding $^8$Be+$^{16}$O and $^{12}$C+$^{12}$C decays,"Exotic $^8$Be and $^{12}$C decays from high-lying resonances in $^{24}$Mg are
analyzed in terms of a cluster model. The calculated quantities agree well with
the corresponding experimental data. It is found that the calculated decay
widths are very sensitive to the angular momentum carried by the outgoing
cluster. It is shown that this property makes cluster decay a powerful tool to
determine the spin as well as the molecular structures of the resonances.",1006.1071v1
2010-07-06,Extraction of the resonance parameters at finite times,"In this paper we propose a model-independent method to extract the resonance
parameters on the lattice directly from the Euclidean 2-point correlation
functions of the field operators at finite times. The method is tested in case
of the two-point function of the Delta-resonance, calculated at one loop in
Small Scale Expansion. Further, the method is applied to a 1+1-dimensional
model with two coupled Ising spins and the results are compared with earlier
ones obtained by using Luescher's approach.",1007.0860v1
2011-05-06,Radio frequency readout of electrically detected magnetic resonance in phosphorus-doped silicon MOSFETs,"We demonstrate radio frequency (RF) readout of electrically detected magnetic
resonance in phosphorus-doped silicon metal-oxide field-effecttransistors
(MOSFETs), operated at liquid helium temperatures. For the first time, the Si:P
hyperfine lines have been observed using radio frequency reflectometry, which
is promising for high-bandwidth operation and possibly time-resolved detection
of spin resonance in donor-based semiconductor devices. Here we present the
effect of microwave (MW) power and MOSFET biasing conditions on the EDMR
signals.",1105.1235v1
2012-03-01,Current-induced resonance in a ferromagnet - antiferromagnet junction,"We calculate the response of a ferromagnet - antiferromagnet junction to a
high-frequency magnetic field as a function of the spin-polarized current
through the junction. Conditions are choused under which the response is zero
in absence of such a current. It is shown that increasing in the current
density leads to proportional increase in the resonance frequency and resonant
absorption. A principal possibility is indicated of using ferromagnet -
antiferromagnet junction as a terahertz radiation detector.",1203.0114v1
2012-05-24,Resonances in 28Si+28Si. I,"A molecular model developed for resonances observed in medium light heavy-ion
collisions is described. At high spins in 28Si+28Si (oblate-oblate system), a
stable dinuclear configuration is found to be equator-equator touching one. The
normal modes around the equilibrium are investigated. These modes are expected
to be the origin of a large number of resonances observed. Furthermore, due to
the axially asymmetric shape of the stable configuration of 28Si+28Si, the
system rotates preferentially around the axis with the largest moment of
inertia, which gives rise to wobbling motion ($K$-mixing). Energy spectra for
the normal modes and for the extended model including the wobbling motion are
given.",1205.5490v1
2013-05-23,Composite or elementary? Probing the nature of the Higgs,"I discuss consequences of electroweak symmetry breaking by strong dynamics,
assuming the existence of a light composite scalar appearing as a
pseudo-Goldstone boson of some global symmetry of the new strongly interacting
sector. In such a scenario, the composite scalar has properties very similar to
the Standard Model Higgs, but the existence of additional resonances with
different spins is also expected. Properties and phenomenology of lightest
spin-1 resonances are considered in a simple general effective Lagrangian
description. The question whether the effects of spin-1 resonances can be
observed at the LHC, shedding light on the nature of the Higgs boson, is
addressed.",1305.5364v1
2013-08-01,Field Theory of the d+t -> n+alpha Reaction Dominated by a 5He* Unstable Particle,"An effective, non-relativistic field theory for low-energy d+t -> n+alpha
reaction is presented. The theory assumes that the reaction is dominated by an
intermediate 5He* unstable spin 3/2+ resonance. It involves two parameters in
the coupling of the d+t and n+alpha particles to the unstable resonant state,
and the resonance energy level -- only three real parameters in all. All
Coulomb corrections to this process are computed. The resultant field theory is
exactly solvable and provides an excellent description of the d+t fusion
process.",1308.0347v1
2013-12-21,Probing the localization length of photo-generated charges in organic materials,"We report a new experimental method to measure the localization length of
photo-generated carriers in an organic donor-acceptor photovoltaic blend by
comparing their dielectric and electron spin-resonance susceptibilities which
are simultaneously measured by monitoring the resonance frequency of a
superconducting resonator. We show that at cryogenic temperatures excitons are
dissociated into long lived states, but that these are confined within a
separation of around $4\;{\rm nm}$. We determine the Debye and recombination
times, showing the coexistence of a fast electrical response corresponding to
delocalized motion, with glass-like recombination kinetics.",1312.6245v1
2014-03-05,Resonant detection of axion mediated forces with Nuclear Magnetic Resonance,"We describe a method based on precision magnetometry that can extend the
search for axion-mediated spin-dependent forces by several orders of magnitude.
By combining techniques used in nuclear magnetic resonance and short-distance
tests of gravity, our approach can substantially improve upon current
experimental limits set by astrophysics, and probe deep into the theoretically
interesting regime for the Peccei-Quinn (PQ) axion. Our method is sensitive to
PQ axion decay constants between 10^9 and 10^12 GeV or axion masses between
10^-6 and 10^-3 eV, independent of the cosmic axion abundance.",1403.1290v1
2015-03-12,Chirp spectroscopy applied to the characterization of Ferromagnetic Resonance in Magnetic Tunnel Junctions,"Magnetic Tunnel Junction devices find use in several applications based on
the exploitation of the Spin-Transfer Torque phenomenon. The Ferromagnetic
Resonance curve is a key characteristic of any Magnetic Tunnel Junctions. It is
usually characterized both experimentally and numerically by performing a lot
of measurements of the magnetic response to a sinusoidal field or current. Here
we propose the use of a chirp signal as excitation signal to reconstruct the
Ferromagnetic resonance curve with a single measurement/simulation. A
micromagnetic comparison of the proposed method with the traditional one is
shown.",1503.03719v1
2015-07-16,Antiferromagentic resonance detected by DC voltages in MnF$_2$/Pt bilayers,"We performed coplanar waveguide-based broadband ferromagnetic resonance
experiments on the antiferromagnetic insulator MnF$_2$, while simultaneously
recording the DC voltage arising in a thin platinum film deposited onto the
MnF$_2$. The antiferromagnetic resonance is clearly reflected in both the
transmission through the waveguide as well as the DC voltage in the Pt strip.
The DC voltage remains largely unaffected by field reversal and thus presumably
stems from microwave rectification and/or heating effects. However, we identify
a small magnetic field orientation dependent contribution, compatible with
antiferromagnetic spin pumping theory.",1507.04490v1
2016-01-23,Nonlinear magnetization dynamics of antiferromagnetic spin resonance induced by intense terahertz magnetic field,"We report on the nonlinear magnetization dynamics of a HoFeO3 crystal induced
by a strong terahertz magnetic field resonantly enhanced with a split ring
resonator and measured with magneto-optical Kerr effect microscopy. The
terahertz magnetic field induces a large change (~40%) in the spontaneous
magnetization. The frequency of the antiferromagnetic resonance decreases in
proportion to the square of the magnetization change. A modified
Landau-Lifshitz-Gilbert equation with a phenomenological nonlinear damping term
quantitatively reproduced the nonlinear dynamics.",1601.06213v1
2016-04-21,Interaction of two magnetic resonance modes in polar phase of superfluid 3He,"We report results of low frequency nuclear magnetic resonance (NMR)
experiments in the superfluid polar phase of 3He which is stabilized by a new
type of ""nematic"" aerogel - nafen. We have found that an interaction between
transverse and longitudinal NMR modes may essentially influence the spin
dynamics. Theoretical formulas for NMR resonant frequencies are derived and
applied for interpretation of the experimental results.",1604.06233v1
2016-05-21,Propagators of resonances and rescatterings of the decay products,"Hadronic resonance propagators which take into account the analytical
properties of decay processes are built in terms of the dispersion relation
technique. Such propagators can describe multi-component systems, for example,
those when quark degrees of freedom create a resonance state, and decay
products correct the corresponding pole by adding hadronic deuteron-like
components. Meson and baryon states are considered, examples of particles with
different spins are presented.",1605.06605v2
2016-06-30,Numeric calculation of antiferromagnetic resonance frequencies for the noncollinear antiferromagnet,"We present an algorithm for the numeric calculation of antiferromagnetic
resonance frequencies for the non-collinear antiferromagnets of general type.
This algorithm uses general exchange symmetry approach \cite{andrmar} and is
applicable for description of low-energy dynamics of an arbitrary noncollinear
spin structure in weak fields. Algorithm is implemented as a MatLab and C++
program codes, which are available for download. Program codes are tested
against some representative analytically solvable cases.",1606.09394v1
2016-09-28,Resonant Enhancement of Second Harmonic Generation by Edge States in Transition Metal Dichalcogenide Monolayers,"We derive a low-energy theory for edge states in transition metal
dichalcogenide monolayers for a two-band $\bm{kp}$-Hamiltonian in case of
uncoupled valleys. In the absence of spin-orbit interaction at the edge, these
states possess a linear dispersion described by a single phenomenological
parameter characterizing the edge structure. Depending on the sign of the
parameter, the edge state spectrum can either cross the band gap or lie outside
of it. In the first case, the presence of edge states leads to resonant
enhancement of the second harmonic generation at frequencies about the half of
the band gap, in agreement with recent experiments. The value of the
phenomenological boundary parameter is extracted from the resonance frequency
position.",1609.08946v1
2017-11-10,GenEx - Exclusive Meson Generator,"Exclusive light meson production processes possible to be measured at RHIC
and LHC accelerators are briefly described. This includes Pomeron and photon
induced continuum of pions and kaons as well as $f_0$ and $\rho^0$ resonant
production. Next, GenEx, a new Monte Carlo generator recently developed in
Cracow, is presented. Its purpose is to generate resonant and non-resonant pion
and kaon production and diffractive Bremsstrahlung. Its future development will
take into account spin (polarization) effects and simulate corrections due to
absorption and re-scattering.",1711.03797v2
2018-06-05,Resonant photoemission with circular polarized light on magnetized LSMO,"We have used resonant photoemission with circular polarized light as a new
tool to obtain information about the electronic structure of half-metals. After
careful sample surface preparation of La0.7Sr0.3MnO3, we have obtained a
dichroic signal for the L2,3 absorption of Mn. Working with a magnetized sample
and circular polarized light we observe a clear effect of the helicity of light
on the position of the resonant Raman-Auger photoelectrons from the Mn 2p3p3d
decay. These results allow us to achieve a rough estimate of the half-metallic
spin half-gap.",1806.01833v1
2018-09-24,Superefficient cascade multiresonator quantum memory,"We propose a cascade scheme of a superefficient broadband quantum memory
consisting of four high-Q ring resonators forming a controllable frequency comb
and interacting with long-lived spin systems and with a common waveguide. Using
the transfer function giving extended matching conditions, the optimization of
all spectroscopic parameters of the system for quantum memory in the resonator
is carried out. It was shown that our quantum memory scheme does not impose
large restrictions on the parameters of losses in resonators and allows to
achieve super high efficiency 99.99 % in a wide frequency range.",1809.08759v2
2017-02-13,Resonant Generation of an Electron-Positron Pair by Two Photons to Excited Landau Levels,"We consider the resonant generation of an electron-positron pair by two
polarized photons to arbitrarily low Landau levels. The resonance occurs when
the energy of one photon exceeds the one-photon generation threshold, and the
energy of the other photon is multiple to the spacing between the levels. The
cross section of the process is determined taking into account the spins of
particles. The order of magnitude of the cross section is the highest when the
magnetic moments of the particles are oriented along the magnetic field.",1702.03693v1
2008-06-09,Quark-Model Identification of Baryon Ground and Resonant States,"We present a new classification scheme of baryon ground states and resonances
into SU(3) flavor multiplets. The scheme is worked out along a covariant
formalism with relativistic constituent quark models and it relies on detailed
investigations of the baryon spectra, the spin-flavor structure of the baryon
eigenstates, the behaviour of their probability density distributions as well
as covariant predictions for mesonic decay widths. The results are found to be
quite independent of the specific types of relativistic constituent quark
models employed. It turns out that a consistent classification requires to
include also resonances that are presently reported from experiment with only
two-star status.",0806.1454v1
2016-11-22,Photons Squeezing Model in a Nonlinear Micro-ring Resonator,"Principally, there are two forms of coupling energy when particle(photon) is
moving around the micro-ring resonator, which is generated by the construction
(creation) and the destruction (annihilation) energies that can disturb the
centre nonlinear microring resonator and lead the system unstable from the
harmonic motion, from which the squeezing state of the particle can occur. The
detected outputs either electrons and their spins or photons can be useful for
the new era of electronic devices and circuits, where the classical
electronics, plasmonic electronics, spintronic electronics and quantum
electronics can be combined and realized.",1611.07520v3
2017-03-04,Structure of 10N in 9C+p resonance scattering,"The structure of exotic nucleus 10N was studied using 9C+p resonance
scattering. Two L=0 resonances were found to be the lowest states in 10N. The
ground state of 10N is unbound with respect to proton decay by 2.2(2) or 1.9(2)
MeV depending on the 2- or 1- spin-parity assignment, and the first excited
state is unbound by 2.8(2) MeV.",1703.01366v1
2019-01-14,Quantum simulation scheme of two-dimensional xy-model Hamiltonian with controllable coupling,"We study a scheme of quantum simulator for two-dimensional xy-model
Hamiltonian. Previously the quantum simulator for a coupled cavity array spin
model has been explored, but the coupling strength is fixed by the system
parameters. In the present scheme several cavity resonators can be coupled with
each other simultaneously via an ancilla qubit. In the two-dimensional Kagome
lattice of the resonators the hopping of resonator photonic modes gives rise to
the tight-binding Hamiltonian which in turn can be transformed to the quantum
xy-model Hamiltonian. We employ the transmon as an ancilla qubit to achieve in
situ controllable xy-coupling strength.",1901.04350v1
2019-09-29,Nonlinear Floquet dynamics of spinor condensates in an optical cavity: Cavity-amplified parametric resonance,"We investigate Floquet dynamics of a cavity-spinor Bose-Einstein condensate
coupling system via periodic modulation of the cavity pump laser. Parametric
resonances are predicted and we show that due to cavity feedback-induced
nonlinearity the spin oscillation can be amplified to all orders of resonance,
thus facilitating its detection. Real-time observation on Floquet dynamics via
cavity output is also discussed.",1909.13191v1
2021-01-07,Microwave directional dichroism resonant with spin excitations in the polar ferromagnet GaV$_4$S$_8$,"We have investigated the directional dichroism of magnetic resonance spectra
in the polar ferromagnet GaV$_4$S$_8$. While four types of structural domains
are energetically degenerated under zero field, the magnetic resonance for each
domain is well separated by applying magnetic fields due to uniaxial magnetic
anisotropy. Consequently, the directional dichroism as large as 20 % is clearly
observed without domain cancellation. The present observation therefore
demonstrates that not only magnetoelectric mono-domain crystals but also
magnetoelectric multi-domain specimens can be used to realize microwave
(optical) diodes owing to the lack of inversion domains.",2101.02411v1
2022-03-02,Observation of microcavity fine structure,"We observe fine structure in the resonance spectra of optical microcavities.
We identify the polarization-resolved modes in the spectrum and find that
resonance frequencies split in accordance with the theoretical prediction. The
observed fine structure is dominantly caused by an optical spin-orbit coupling
and non-paraxial propagation and reflection. Both effects are intrinsic, i.e.
present in an ideal rotation-symmetric system, and scale inversely proportional
to the mirror radius of curvature. For cavities with a small radius of
curvature, the influence of fine structure on the resonance spectrum is
important and unavoidable and should thus be taken into account.",2203.01200v1
2022-09-26,High temperature spectroscopy of nitrogen vacancy centers in diamond,"We study spectroscopy of negatively charged nitrogen-vacancy center in
diamond at high temperatures under high vacuum conditions. Spin resonances are
studied using optical detection of magnetic resonance (ODMR), and optical
spectroscopy is employed to study radiative transitions. Upon increasing the
temperature the intensity of radiative decay in visible and infra-red
decreased. In addition, the ODMR resonance frequencies were decreased, and the
phonon line emission shifted to higher wavelengths. Fitting the measured
intensity of photo-luminescence with the theoretical predictions of the
Mott-Seitz model yields the value of $0.24 \operatorname{eV}$ for the energy
barrier associated with nonradiative decay.",2209.12558v3
2023-04-19,Resonant and polarization effects in the processes of quantum electrodynamics in a strong magnetic field,"The monograph considers resonance and polarization effects in quantum
electrodynamics processes that take place in a strong external magnetic field.
A method for analyzing spin-polarization effects has been developed. The
factorization of process cross sections in resonant conditions and the
representation of these cross sections in the form of Breit-Wigner are
considered. The possibility of testing these effects in modern international
projects to test quantum electrodynamics in strong fields is shown.",2304.09484v1
2003-12-15,Interpreting black hole QPOs,"In all the microquasars with two hHz QPOs, the ratio of the frequencies is
3:2, supporting our suggestion that a non-linear resonance between two modes of
oscillation in the accretion disk plays a role in exciting the observed
modulations of the X-ray flux. We discuss the evidence in favor of this
interpretation, and we relate the black hole spin to the frequencies expected
for various types of resonances that may occur in nearly Keplerian disks in
strong gravity. For those microquasars where the mass of the central X-ray
source is known, the black hole spin can be deduced from a comparison of the
observed and expected frequencies.",0312396v1
1994-03-10,Resonating Valence Bond Theory of Coupled Heisenberg Chains,"Using numerical results from a density matrix renormalization group study as
a guide, we develop a resonating valence bond (RVB) theory for coupled
Heisenberg chains. We argue that simple topological effects mandate a
short-range RVB description of systems with an even number of chains $n_c$,
with a spin gap, short-range correlations, and confinement of topological spin
defects. Odd-$n_c$ systems have long-range RVB ground states, no gap, and
power-law correlations.",9403042v2
1995-11-07,Plaquette Resonating-Valence-Bond Ground State of CaV$_4$O$_9$,"A theoretical model is presented to explain the spin gap observed for
CaV$_4$O$_9$. The underlying lattice of the 1/5-depleted square lattice favors
a formation of plaquette resonating valence bond state. Inclusion of the
frustrating second neighbor interaction enhances this tendency, leading to a
quantum disordered state of a two dimensional spin-1/2 Heisenberg model with a
sufficiently big spin gap compatible with experiments.",9511034v2
1996-11-15,Magnetic Dynamics in Underdoped YBCO: Direct Observation of a Superconducting Gap,"Polarized and unpolarized triple-axis spectrometry has been used to study an
underdoped YBa_2Cu3O6.6. Our results indicate that spin excitations in the
superconducting state are essentially the same as those in the fully doped
material except that the unusual 41 meV resonance is observed at 34.8 meV. The
normal state spin excitations are characterized by a weakly energy-dependent
continuum whose temperature dependence shows the clear signature of a
superconducting gap at Tc. The enhancement at the resonance is accompanied by a
suppression of magnetic fluctuations at both higher and lower energies.",9611123v1
1997-04-29,Stochastic resonance and nonlinear response in a dissipative quantum two-state system,"We study the dynamics of a dissipative two-level, system driven by a
monochromatic ac field, starting from the usual spin-boson Hamiltonian. The
quantum Langevin equations for the spin variables are obtained. The amplitude
of the coherent oscillations in the average position of the particle is studied
in the high temperature limit. The system exhibits quantum stochastic resonance
in qualitative agreement with earlier numerical results.",9704243v1
1998-06-19,Integrable Impurity Model with Spin and Flavour: Model Inspired by Resonant Tunneling in Quantum Dot,"We introduce an integrable impurity model in which both electrons and
impurity have spin and flavour degrees of freedom. This model is a
generalization of the multi-channel Kondo model and closely related with
resonant tunneling through quantum dot. The Hamiltonian is exactly diagonalized
by means of the Bethe ansatz.",9806227v4
2000-06-06,A critical examination of the spin dynamics in high-$T_C$ cuprates,"A critical examination of the spin dynamics in high-$T_C$ cuprates is made on
the light of inelastic neutron scattering results obtained by different groups.
Recent neutron data show that incommensurate magnetic peaks in YBCO belong to
the same excitation as the resonance peak observed at $(\pi/a,\pi/a)$. Being
only observed in the superconducting state, the incommensurability is then
rather difficult to reconcile with a stripe picture. We also discuss the link
between the resonance peak spectral weight and the superconducting condensation
energy.",0006085v2
2000-11-16,Coordinate Representation of the Two-Spinon wavefunction and Spinon Interaction,"By deriving and studying the coordinate representation for the two-spinon
wavefunction, we show that spinon excitations in the Haldane-Shastry model
interact. The interaction is given by a short-range attraction and causes a
resonant enhancement in the two-spinon wavefunction at short separations
between the spinons. We express the spin susceptibility for a finite lattice in
terms of the resonant enhancement, given by the two-spinon wavefunction at zero
separation. In the thermodynamic limit, the spinon attraction turns into the
square-root divergence in the dynamical spin susceptibility.",0011270v1
2000-12-21,Optics with an Atom Laser Beam,"We report on the atom optical manipulation of an atom laser beam. Reflection,
focusing and its storage in a resonator are demonstrated. Precise and versatile
mechanical control over an atom laser beam propagating in an inhomogeneous
magnetic field is achieved by optically inducing spin-flips between atomic
ground states with different magnetic moment. The magnetic force acting on the
atoms can thereby be effectively switched on and off. The surface of the atom
optical element is determined by the resonance condition for the spin-flip in
the inhomogeneous magnetic field. A mirror reflectivity of more than 98% is
measured.",0012398v2
2001-02-26,Correlation of Tunneling Spectra in Bi2Sr2CaCu2O(8+delta) with the Resonance Spin Excitation,"New break-junction tunneling data are reported in Bi2Sr2CaCu2O(8+delta) over
a wide range of hole concentration from underdoped (Tc = 74 K) to optimal doped
(Tc = 95 K) to overdoped (Tc = 48 K). The conductances exhibit sharp dips at a
voltage, Omega/e, measured with respect to the superconducting gap. Clear
trends are found such that the dip strength is maximum at optimal doping and
that Omega scales as 4.9 kTc over the entire doping range. These features link
the dip to the resonance spin excitation and suggest quasiparticle interactions
with this mode are important for superconductivity.",0102475v1
2002-06-10,Magnetic anisotropy of BaCu2Si2O7: theory and antiferromagnetic resonance,"Antiferromagnetic resonance (AFMR) of BaCu2Si2O7 and a microscopic theory of
the magnetic anisotropy of spin 1/2 chain compounds with folded CuO3 geometry
being in good agreement with the available data are presented. The AFMR studies
at 4.2 K show the existence of two gaps (40 and 76 GHz) at zero magnetic field
and of two spin re-orientation transitions for H||c. The microscopic origin of
the two gaps is shown to be Hund's rule coupling which leads to a ""residual
anisotropy"" beyond the compensation of the Dzyaloshinskii-Moriya term by the
symmetric anisotropy which would be valid without Hund's coupling.",0206151v1
2002-11-26,ESR investigation of the spin dynamics in (Gd_{1-x}Y_{x})_2PdSi_{3},"We report electron-spin resonance measurements in polycrystalline samples of
(Gd_{1-x}Y_{x})_2PdSi_{3}. We observe the onset of a broadening of the
linewidth and of a decrease of the resonance field at approximately twice the
Neel temperature in the paramagnetic state, this characteristic temperature
coincides with the electrical resistivity minimum. The high-temperature
behaviour of the linewidth is governed by a strong bottleneck effect.",0211587v1
2002-12-28,Charge Freezing in Zig-zag Chain Cuprates PrBa2Cu4O8 Observed by Cu Nuclear Quadrupole Resonance,"We report nuclear quadrupole resonance (NQR) studies on the chain Cu sites of
PrBa$_{2}$Cu$_{4}$O$_{8}$, a quasi-one-dimensional conductor with a nearly
quarter-filled band. The nuclear spin-lattice relaxation rate $1/T_{1}$ shows a
pronounced peak near 100 K caused by fluctuations of electric field gradient
(EFG). Similar peak was observed for the spin-echo decay rate $1/T_{2}$,
however, at a different temperature near 50 K. These results and broadening of
the NQR spectrum at low temperatures indicate that slow charge fluctuations of
either electronic or ionic origin freeze gradually at low temperatures.",0212621v1
2003-06-11,Random Spin Signal in Magnetic Resonance Force Microscopy,"We study a random magnetic resonance force microscopy (MRFM) signal caused by
the thermal vibrations of high frequency cantilever modes in the oscillating
cantilever-driven adiabatic reversals (OSCAR) technique. We show that the
regular MRFM signal with a characteristic decay time, $\tau_m$, is followed by
a non-dissipative random signal with a characteristic time $\tau_r$. We present
the estimates for the values of $\tau_m$ and $\tau_r$. We argue that this
random MRFM signal can be used for spin detection. It has a ``signature'' of a
sharp peak in its Fourier spectrum.",0306292v1
2003-08-20,Theory for Gossamer and Resonating Valence Bond Superconductivity,"We use an effective Hamiltonian for two-dimensional Hubbard model including
an antiferromagnetic spin-spin coupling term to study recently proposed
gossamer superconductivity. We formulate a renormalized mean field theory to
approximately take into account the strong correlation effect in the partially
projected Gutzwiller wavefucntions. At the half filled, there is a first order
phase transition to separate a Mott insulator at large Coulomb repulsion U from
a gossamer superconductor at small U. Away from the half filled,the Mott
insulator is evolved into an resonating valence bond state, which is
adiabatically connected to the gossamer superconductor.",0308398v1
2003-11-19,Theory of indirect resonant inelastic X-ray scattering,"We express the cross section for indirect resonant inelastic X-ray scattering
in terms of an intrinsic dynamic correlation function of the system that is
studied with this technique. The cross section is a linear combination of the
charge response function and the dynamic longitudinal spin density correlation
function. This result is asymptotically exact for both strong and weak local
core-hole potentials. We show that one can change the relative charge and spin
contribution to the inelastic spectral weight by varying the incident photon
energy.",0311446v1
2004-01-05,Resonance magneto-resistance in double barrier structure with spin-valve,"The conductance and tunnel magneto-resistance (TMR) of the double barrier
magnetic tunnel junction with spin-valve sandwich (F/P/F) inserted between two
insulating barrier, are theoretically investigated. It is shown, that resonant
tunnelling, due to the quantum well states of the electron confined between two
barriers, sharply depends on the mutual orientation of the magnetizations of
ferromagnetic layers F. The calculated optimistic value of TMR exceeds 2000% .",0401006v2
2004-01-31,Resonant magnetic mode in superconducting 2-leg ladders,"The spin dynamics of a doped 2-leg spin ladder is investigated by numerical
techniques. We show that a hole pair-magnon boundstate evolves at finite hole
doping into a sharp magnetic excitation below the two-particle continuum. This
is supported by a field theory argument based on a SO(6)-symmetric ladder.
Similarities and differences with the resonant mode of the high-T$_c$ cuprates
are discussed.",0402011v1
2004-07-27,Selective optical manipulation of the spin state of a single magnetic impurity in a semiconductor quantum dot,"We consider the optical properties of a single magnetic impurity in a
self-assembled quantum dot. We show that using the resonant pumping one can
address and manipulate selectively individual spin states of a magnetic
impurity. The mechanisms of resonant optical polarization of a single impurity
in a quantum dot involve anisotropic exchange interactions and are different to
those in diluted semiconductors. A Mn impurity can act as qubit. The limiting
factors for the qubit manipulation are the electron-hole exchange interaction
and finite temperature.",0407705v1
2005-02-07,Electron paramagnetic resonance detected via magnetization measurements,"Presented are magnetization measurements on a crystal of Fe8 single-molecule
magnets using a Hall probe magnetometer. Irradiation with microwaves at
frequencies of 92 and 110-120 GHz leads to the observation of electron
paramagnetic resonance (EPR) detected via magnetization measurements. A
quantitative analysis of the results are introduced by means of the spin
temperature. It is shown that pulsed microwave experiments allow a better
control over the spin excitation.",0502175v1
2005-08-19,Resonant Tunneling in Truly Axial Symmetry Mn12 Single-Molecule Magnets: Sharp Crossover between Thermally Assisted and Pure Quantum Tunneling,"Magnetization measurements of a truly axial symmetry Mn12-tBuAc molecular
nanomagnet with a spin ground state of S = 10 show resonance tunneling. This
compound has the same magnetic anisotropy as Mn12-Ac but the molecules are
better isolated and the crystals have less disorder and a higher symmetry.
Hysteresis loop measurements at several temperatures reveal a well-resolved
step fine-structure which is due to level crossings of excited states. All step
positions can be modeled by a simple spin Hamiltonian. The crossover between
thermally assisted and pure quantum tunneling can be investigated with
unprecedented detail.",0508437v1
2005-09-09,Quantum trajectory analysis for electrical detection of single-electron spin resonance,"A Monte Carlo simulation on the basis of quantum trajectory approach is
carried out for the measurement dynamics of a single electron spin resonance.
The measured electron, which is confined in either a quantum dot or a defect
trap, is tunnel-coupled to a side reservoir and continuously monitored by a
mesoscopic detector. The simulation not only recovers the observed telegraphic
signal of detector current, but also predicts unique features in the output
power spectrum which are associated with electron dynamics in different
regimes.",0509228v2
2006-01-12,Comment on On the Yield of Singlet Excitons in Organic Light-Emitting Devices: a Double Modulation Photoluminescence-Detected Magnetic Resonance Study,"In a recent Letter Lee et al. studied the spin 1/2 photoluminescence-detected
magnetic resonance (PLDMR) of a soluble derivative of poly-phenylene vinylene
[MEH-PPV] and argued that it originates from the interaction of triplet
excitons with polarons. We show that in MEH-PPV as well as in other conjugated
polymers the spin 1/2 PLDMR does not depend on the triplet exciton density and
thus cannot be associated with triplet excitons.",0601246v1
2006-06-30,Momentum-resolved electron-phonon interaction in lead determined by neutron resonance spin-echo spectroscopy,"Neutron resonance spin-echo spectroscopy was used to monitor the temperature
evolution of the linewidths of transverse acoustic phonons in lead across the
superconducting transition temperature, $T_c$, over an extended range of the
Brillouin zone. For phonons with energies below the superconducting energy gap,
a linewidth reduction of maximum amplitude $\sim 6 \mu$eV was observed below
$T_c$. The electron-phonon contribution to the phonon lifetime extracted from
these data is in satisfactory overall agreement with {\it ab-initio}
lattice-dynamical calculations, but significant deviations are found.",0606816v1
2006-08-10,Gate-controlled nuclear magnetic resonance in an AlGaAs/GaAs quantum Hall device,"We study the resistively detected nuclear magnetic resonance (NMR) in an
AlGaAs/GaAs quantum Hall device with a side gate. The strength of the hyperfine
interaction between electron and nuclear spins is modulated by tuning a
position of the two-dimensional electron systems with respect to the polarized
nuclear spins using the side-gate voltages. The NMR frequency is systematically
controlled by the gate-tuned technique in a semiconductor device.",0608237v1
1999-09-25,On the Resonant Spin Flavor Precession of the Neutrino in the Sun,"This work deals with the possible solution of the solar neutrino problem in
the framework of the resonant neutrino spin-flavor precession scenario. The
event rate results from the solar neutrino experiments as well as the recoil
electron energy spectrum from SuperKamiokande are used to constrain the free
parameters of the neutrino in this model. We consider two kinds of magnetic
profiles inside the sun. For both cases, a static and a twisting field are
discussed.",9909512v1
2004-05-24,Composite Vector Mesons from QCD to the Little Higgs,"We review how the rho meson can be modeled in an effective theory and discuss
the implications of applying this approach to heavier spin-one resonances.
Georgi's vector limit is explored, and its relationship to locality in a
deconstructed extra-dimension is discussed. We then apply the formalism for
rho's to strongly coupled theories of electroweak symmetry breaking, studying
the lightest spin-one techni-rho resonances. Understanding these new particles
in Little Higgs models can shed light on previously incalculable, ultraviolet
sensitive physics, including the mass of the Higgs boson.",0405242v1
2006-04-07,The sum rules for the spin dependent structure functions $g_1$ in the isovector reaction,"In the isovector reaction, the sum rule for the spin dependent function $g_1$
which is related to the cross section of the photoproduction is derived. In the
small $Q^2$ region, the sum rule is dominated by the low energy contribution
and it tightly connects the resonance, the elastic, and the non-resonant
contributions.",0604073v2
2007-01-28,The constraint on the spin dependent structure function $g_1$ at low $Q^2$ through the sum rule corresponding to the moment at $n=0$,"The sum rules for the spin dependent structure function $g_1^{ab}$ in the
null-plane formalism corresponding to the moment at $n=0$ has been transformed
to the sum rule which relates the $g_1^{ab}$ with the cross section of the
isovector photon or the real photon. Based on these sum rules, we argue that
there is a deep connection among the elastic, the resonance, and the
non-resonant contributions, and that it explains why the sign of the
generalized Gerasimov-Drell-Hearn sum changes at very small $Q^2$.",0701236v1
2000-02-09,Polarization phenomena in the reaction NN to NNpi near threshold,"First calculations for spin-dependent observables of the reactions $pp \to
pp\pi^0$, $pp \to pn\pi^+$ and $pp \to d\pi^+$ near threshold are presented,
employing the J\""ulich model for pion production. The influence of resonant
(via the excitation of the $\Delta (1232)$) and non-resonant p-wave pion
production mechanisms on these observables is examined. For the reactions $pp
\to pn\pi^+$ and $pp \to d\pi^+$ nice agreement of our predictions with the
presently available data on spin correlation coefficents is observed whereas
for $pp \to pp\pi^0$ the description of the data is less satisfying.",0002025v1
2003-02-25,Realistic simulations of single-spin nondemolition measurement by magnetic resonance force microscopy,"A requirement for many quantum computation schemes is the ability to measure
single spins. This paper examines one proposed scheme: magnetic resonance force
microscopy, including the effects of thermal noise and back-action from
monitoring. We derive a simplified equation using the adiabatic approximation,
and produce a stochastic pure state unraveling which is useful for numerical
simulations.",0302178v1
2007-07-27,Direct observation of mixing of spin-multiplets in an antiferromagnetic molecular nanomagnet by electron paramagnetic resonance,"High-frequency electron paramagnetic resonance (EPR) studies of the
antiferromagnetic Mn-$[3\times 3]$ molecular grid clearly reveal a breaking of
the $\Delta S = 0$ selection rule, providing direct evidence for the mixing of
spin wavefunctions ($S$-mixing) induced by the comparable exchange and
magneto-anisotropy energy scales within the grid. This finding highlights the
potential utility of EPR for studies of exchange splittings in molecular
nanomagnets, which is normally considered the sole domain of inelastic neutron
scattering, thereby offering improved sensitivity and energy resolution.",0707.4109v1
2007-10-04,Deuteron spin structure functions in the resonance and DIS regions,"We derive relations between spin-dependent nuclear and nucleon g_1 and g_2
structure functions within the nuclear impulse approximation, which are valid
at all Q^2, and in both the resonance and deep inelastic regions. We apply the
formalism to the specific case of the deuteron, which is often used as a source
of neutron structure information, and compare the size of the nuclear
corrections calculated using exact kinematics and using approximations
applicable at large Q^2.",0710.1101v4
2008-05-18,The Aharonov-Bohm-Casher ring-dot as a flux-tunable resonant tunneling diode,"A mesoscopic ring subject to the Rashba spin-orbit interaction and
sequentially coupled to an interacting quantum dot, in the presence of
Aharonov-Bohm flux, is proposed as a flux tunable tunneling diode. The analysis
of the conductance by means of the nonequilibrium Green's function technique,
shows an intrinsic bistability at varying the Aharonov-Bohm flux when 2U > \pi
\Gamma, U being the charging energy on the dot and \Gamma the effective
resonance width. The bistability properties are discussed in connection with
spin-switch effects and logical storage device applications.",0805.2715v1
2008-09-23,Spin structure functions of 3He at finite Q^2,"Using recently derived relations between spin-dependent nuclear and nucleon
g_1 and g_2 structure functions at finite Q^2, we study nuclear effects in 3He
in the nucleon resonance and deep inelastic regions. Comparing the finite-Q^2
results with the standard convolution formulas obtained in the large-Q^2 limit,
we find significant broadening of the effective nucleon momentum distribution
functions, leading to additional suppression of the nuclear g_1 and g_2
structure functions around the resonance peaks.",0809.3998v2
2009-03-22,Spin resonance in chiral helimagnet,"It is suggested that marked features of symmetry breaking mechanism and
elementary excitations in chiral helimagnet come up as visible effects in
electron spin resonance (ESR) profile. Under the magnetic field applied
parallel and perpendicular to the helical axis, elementary excitations are
respectively described by the helimagnon associated with rotational symmetry
breaking and the magnetic kink crystal phonon associated with translational
symmetry breaking. We demonstrate how the ESR spectra distinguish these
excitations.",0903.3699v2
2009-05-14,Single-Spin Microscope with Sub-Nanoscale Resolution Based on Optically Detected Magnetic Resonance,"We summarize our new scanning magnetic 3-D imaging system. This scanning
system uses optically detected magnetic resonance in a single nitrogen vacancy
center in a diamond nanocrystal. The theoretical analysis and the first
experimental demonstrations have proved that this method has single spin
sensitivity and a sub-nanoscale spatial resolution at room temperature.",0905.2361v1
2009-05-25,Electron Spin Resonance investigation of undoped and Li-doped CdWO_4 scintillator crystals,"Electron spin resonance (ESR) spectra of Fe3+ and Mn2+ ions have been studied
in the nominally pure and 0.05% Li-doped single crystals of CdWO4. The
zero-field splitting parameters are determined with a high precision for both
of the impurities. The result suggest that the Li-doping leads to the increase
of the ionic charge of iron from 3+ to 4+ and of manganese, from 1+ to 2+.",0905.4011v1
2009-08-19,Evolution of the spin resonance in CeCoIn$_5$ under magnetic field,"The evolution of the magnetic excitation spectrum of the unconventional
superconductor CeCoIn$_{5}$ was studied by inelastic neutron scattering as a
function of magnetic field applied in the [1, -1, 0] direction. The spin
resonance characteristic of the superconducting states was observed up to about
$H_{c2}$/2 : it is still centered at (1/2, 1/2, 1/2) when the magnetic field
increases while its characteristic energy decreases and its lineshape
substantially broadens.",0908.2688v1
2009-11-04,Theory of Resonant Inelastic X-ray Scattering by Collective Magnetic Excitations,"I present a tractable theory for the Resonant Inelastic X-ray Scattering
(RIXS) spectral function of magnons. The low-energy transition operator is
written as a product of local spin operators times fundamental x-ray absorption
spectra. This leads to simple selection rules for the magnetic cross section.
The scattering cross section linear (quadratic) in spin operators is
proportional to the magnetic circular (linear) dichroic absorption. RIXS is a
novel tool to measure magnetic quasi particles (magnons) and the incoherent
spectral weight, as well as multiple magnons up to very high energy losses, in
small samples, thin films and multilayers, complementary to Neutron scattering.",0911.0706v2
2010-04-03,The incarnation of the Nersesyan-Tsvelik model in (NO)[Cu(NO3)3],"The topology of the magnetic interactions of the copper spins in the
nitrosonium nitratocuprate (NO)[Cu(NO3)3] suggests that it could be a
realization of the Nersesyan-Tsvelik model, whose ground state was argued to be
either a resonating valence bond (RVB) state or a valence bond crystal (VBC).
The measurement of thermodynamic and resonant properties reveals a behavior
inherent to low dimensional spin S = 1/2 systems and provides indeed no
evidence for the formation of long-range magnetic order down to 1.8 K.",1004.0444v1
2010-09-15,Using Superconducting Qubit Circuits to Engineer Exotic Lattice Systems,"We propose an architecture based on superconducting qubits and resonators for
the implementation of a variety of exotic lattice systems, such as spin and
Hubbard models in higher or fractal dimensions and higher-genus topologies.
Spin systems are realized naturally using qubits, while superconducting
resonators can be used for the realization of Bose-Hubbard models. Fundamental
requirements for these designs, such as controllable interactions between
arbitrary qubit pairs, have recently been implemented in the laboratory,
rendering our proposals feasible with current technology.",1009.2888v2
2011-01-11,Observation of quark-hadron duality in gamma*-p helicity cross sections,"Combining data on unpolarized and polarized inclusive proton structure
functions, we perform the first detailed study of quark-hadron duality in
individual helicity-1/2 and 3/2 virtual photoproduction cross sections. We find
that duality is realized more clearly in the helicity-1/2 channel, with duality
violating corrections < 10% over the entire nucleon resonance region, while
larger, < 20% corrections are found in the helicity-3/2 sector. The results are
in general agreement with quark model expectations, and suggest that data above
the Delta resonance region may be used to constrain both spin-averaged and
spin-dependent parton distributions.",1101.2016v1
2011-02-14,Application of Resonance Perturbation Theory to Dynamics of Magnetization in Spin Systems Interacting with Local and Collective Bosonic Reservoirs,"We apply our recently developed resonance perturbation theory to describe the
dynamics of magnetization in paramagnetic spin systems interacting
simultaneously with local and collective bosonic environments. We derive
explicit expressions for the evolution of the reduced density matrix elements.
This allows us to calculate explicitly the dynamics of the macroscopic
magnetization, including characteristic relaxation and dephasing time-scales.
We demonstrate that collective effects (i) do not influence the character of
the relaxation processes but merely renormalize the relaxation times, and (ii)
significantly modify the dephasing times, leading in some cases to a
complicated (time inhomogeneous) dynamics of the transverse magnetization,
governed by an effective time-dependent magnetic field.",1102.2847v1
2012-07-08,Signatures of Non-Standard Electroweak Symmetry Breaking,"This is the write-up of a talk given at the EW session in Moriond (March
2012). I summarize some non-standard electroweak scenarios, and how they
predict the existence of new spin-two resonances. Spin-two resonances, whether
coming from the compactification of extra-dimensions or from a new sector of
strong interactions, exhibit the same interactions with the Standard Model.
This is a consequence of Lorentz and CP invariance, which we assume would be
preserved by the new strong sector. Although this would seem to support the
holographic duality between strongly interacting theories in four-dimensions
and extra-dimensional theories, I show that there is a way to distinguish
between the two sides of the ""duality"", which constitutes an explicit example
of its breakdown.",1207.1912v1
2012-10-31,Adiabatic Continuation between Resonating-Valence-Bond Electron and Spin Liquids,"The Hubbard model in the strong-coupling regime is studied by the
Kondo-lattice theory. If no symmetry is broken at a sufficiently low
temperature in sufficiently low dimensions, an electron liquid is stabilized by
the Fock-type exchange effect of the superexchange interaction. Since the
stabilization mechanism is none other than the resonating-valence-bond (RVB)
mechanism, the electron liquid is none other than an RVB electron liquid. The
RVB electron liquid in the Hubbard model is adiabatically connected to the RVB
spin liquid in the Heisenberg model.",1210.8211v1
2013-04-01,Fulde-Ferrell superfluidity in ultracold Fermi gases with Rashba spin-orbit coupling,"We theoretically investigate the inhomogeneous Fulde-Ferrell (FF)
superfluidity in a three dimensional atomic Fermi gas with Rashba spin-orbit
coupling near a broad Feshbach resonance. We show that within mean-field theory
the FF superfluid state is always more favorable than the standard
Bardeen-Cooper-Schrieffer (BCS) superfluid state when an in-plane Zeeman field
is applied. We present a qualitative finite-temperature phase diagram near
resonance and argue that the predicted FF superfluid is observable with
experimentally attainable temperatures (i.e., $T\sim0.2T_{F}$, where $T_{F}$ is
the characteristic Fermi degenerate temperature).",1304.0387v2
2013-04-11,Electrically-protected resonant exchange qubits in triple quantum dots,"We present a modulated microwave approach for quantum computing with qubits
comprising three spins in a triple quantum dot. This approach includes single-
and two-qubit gates that are protected against low-frequency electrical noise,
due to an operating point with a narrowband response to high frequency electric
fields. Furthermore, existing double quantum dot advances, including robust
preparation and measurement via spin-to-charge conversion, are immediately
applicable to the new qubit. Finally, the electric dipole terms implicit in the
high frequency coupling enable strong coupling with superconducting microwave
resonators, leading to more robust two-qubit gates.",1304.3407v2
2013-07-15,Theory of the Electron Spin Resonance in the Heavy Fermion Metal β-YbAlB4,"The heavy fermion metal \beta-YbAlB4 exhibits a bulk room temperature
conduction electron ESR signal which evolves into an Ising-anisotropic
f-electron signal exhibiting hyperfine features at low temperatures. We develop
a theory for this phenomenon based on the development of resonant scattering
off a periodic array of Kondo centers. We show that the hyperfine structure
arises from the scattering off the Yb atoms with non zero nuclear spin, while
the constancy of the ESR intensity is a consequence of the presence of CEF
excitations of the order of the hybridization strength.",1307.4109v2
2013-10-01,Isoscalar Giant Resonance Strengths in $^{32}$S and possible excitations of superdeformed and $^{28}$Si + $α$ cluster bandheads,"Isoscalar giant resonances and low spin states in $^{32}$S have been measured
with inelastic $\alpha$ scattering at extremely forward angles including zero
degrees at E$_{\alpha}$ = 386 MeV. By applying the multipole decomposition
analysis, various excited states are classified according to their spin and
parities (J$^{\pi}$), and are discussed in relation to the super deformed and
$^{28}$Si + $\alpha$ cluster bands.",1310.0169v1
2014-02-20,Polarization Test of Higgs Spin and Parity,"A polarization test is applied to determine the spin and the parity of the
observed resonance at LHC, which is believed to be the expected ""Higgs""
particle. The test is based on very general principles and is completely
independent of dynamical assumptions. We have also identified a set of
observables that discriminate resonances with $J^P=0^+,0^-, 2^-$ and $2^+$.
Furthermore, the same set can be used to gain useful and important information
on the magnitude of each helicity amplitude contributing to the $gg\rightarrow
\gamma\gamma$ process .",1402.5117v2
2014-04-04,All-optical high-resolution magnetic resonance using a nitrogen-vacancy spin in diamond,"We propose an all-optical scheme to prolong the quantum coherence of a
negatively charged nitrogen-vacancy (NV) center in diamond. Optical control of
the NV spin suppresses energy fluctuations of the $^{3}\text{A}_{2}$ ground
states and forms an energy gap protected subspace. By optical control, the
spectral linewidth of magnetic resonance is much narrower and the measurement
of the frequencies of magnetic field sources has higher resolution. The optical
control also improves the sensitivity of the magnetic field detection and can
provide measurement of the directions of signal sources.",1404.1190v1
2014-05-08,A single quantum dot as an optical thermometer for mK temperatures,"Resonant laser spectroscopy of a negatively charged self-assembled quantum
dot is utilized to measure the temperature of a three dimensional fermionic
reservoir down to 100mK. With a magnetic field applied to the quantum dot the
single charged ground state is split by the Zeeman energy. As the quantum dot
is in tunnel contact with a thermal electron reservoir, a thermal occupation of
the quantum dot spin states is enforced by co-tunneling processes. Resonant
laser induced fluorescence is used in order to measure the thermal quantum dot
spin state population.",1405.1981v1
2014-05-15,Measuring the Spin and Parity of a Resonance in the Diphoton Decay Channel,"We present a way to determine the spin and parity of a resonance produced
through gluon fusion with a decay to a $\gamma\gamma$ pair based on the
transverse momentum and Collins-Soper $\phi$ distribution. This method also
allows one to distinguish between various non-minimal coupling spin-2 scenarios
and can be used in parallel to the `standard' method based on the polar angle
$\theta$.",1405.3875v1
2014-10-28,Resonant Landau-Zener transitions in helical magnetic fields,"The spin-dependent electron transport has been studied in magnetic
semiconductor waveguides (nanowires) in the helical magnetic field. We have
shown that -- apart from the known conductance dip located at the magnetic
field equal to the helical-field amplitude $B_h$ -- the additional conductance
dips (with zero conductance) appear at magnetic field different from $B_h$.
This effect occuring in the non-adiabatic regime is explained as resulting from
the resonant Landau-Zener transitions between the spin-splitted subbands.",1410.7662v1
2015-05-14,Resonant single and multi-photon coherent transitions in a detuned regime,"We performed quantum manipulations of the multi-level spin system S=5/2 of a
Mn$^{2+}$ ion, by means of a two-tone pulse drive. The detuning between the
excitation and readout radio frequency pulses allows one to select the number
of photons involved in a Rabi oscillation as well as increase the frequency of
this nutation. Thus detuning can lead to a resonant multi-photon process. Our
analytical model for a two-photon process as well as a numerical generalization
fit well the experimental findings, with implications in the use of multi-level
spin systems as tunable solid state qubits.",1505.03649v1
2015-10-01,Effect of Geomagnetism on 101Ru Nuclear Quadrupole Resonance Measurements of CeRu2,"We performed 101Ru nuclear quadrupole resonance (NQR) measurements on the
s-wave superconductor CeRu2 and found oscillatory behavior in the spin-echo
amplitude at the +-1/2 <-> +-3/2 transitions but not at the +-3/2 <-> +-5/2
transitions. The modulation disappears in the superconducting state or in a
magnetic shield, which implies a geomagnetic field effect. Our results indicate
that the NQR spin-echo decay curve at the +-1/2 <-> +-3/2 transitions is
sensitive to a weak magnetic field.",1510.00107v1
2016-09-08,Kondo resonance of a Co atom exchange coupled to a ferromagnetic tip,"The Kondo effect of a Co atom on Cu(100) was investigated with a
low-temperature scanning tunneling microscope using a monoatomically sharp
nickel tip. Upon a tip-Co contact, the differential conductance spectra exhibit
a spin-split asymmetric Kondo resonance. The computed ab initio value of the
exchange coupling is too small to suppress the Kondo effect, but sufficiently
large to produce the splitting observed. A quantitative analysis of the line
shape using the numerical renormalization group technique indicates that the
junction spin polarization is weak.",1609.02363v1
2017-07-10,Spontaneous and Superfluid Chiral Edge States in Exciton-Polariton Condensates,"We present a scheme of interaction-induced topological bandstructures based
on the spin anisotropy of exciton-polaritons in semiconductor microcavities. We
predict theoretically that this scheme allows the engineering of topological
gaps, without requiring a magnetic field or strong spin-orbit interaction
(transverse electric-transverse magnetic splitting). Under non-resonant
pumping, we find that an initially topologically trivial system undergoes a
topological transition upon the spontaneous breaking of phase symmetry
associated with polariton condensation. Under resonant coherent pumping, we
find that it is also possible to engineer a topological dispersion that is
linear in wavevector -- a property associated with polariton superfluidity.",1707.02776v1
2017-11-19,Superefficient long-lived multiresonator quantum memory,"In this paper, we propose a scheme of a long-lived broadband superefficient
multiresonator quantum memory in which a common resonator is connected with an
external waveguide and with a system of high-quality miniresonators containing
long-lived resonant electron spin ensembles. The scheme with 4 miniresonators
has been analyzed in details and it was shown that it is possible to store an
input broadband signal field to the electron spin ensembles with quantum
efficiency 99.99%. The considered multiresonator system opens the way to
elaboration of efficient multiqubit quantum memory devices for superconducting
quantum computer.",1711.07014v1
2017-11-20,Electron paramagnetic resonance g-tensors from state interaction spin-orbit coupling density matrix renormalization group,"We present a state interaction spin-orbit coupling method to calculate
electron paramagnetic resonance (EPR) $g$-tensors from density matrix
renormalization group wavefunctions. We apply the technique to compute
$g$-tensors for the \ce{TiF3} and \ce{CuCl4^2-} complexes, a [2Fe-2S] model of
the active center of ferredoxins, and a \ce{Mn4CaO5} model of the S2 state of
the oxygen evolving complex. These calculations raise the prospects of
determining $g$-tensors in multireference calculations with a large number of
open shells.",1711.07195v3
2017-12-08,$^{89}$Y nuclear spin-lattice relaxation in SrY$_2$O$_4$:Ho$^{3+}$ single crystals,"Measurements of 89Y nuclear spin-lattice relaxation in SrY2O4:Ho3+ crystals
for the magnetic field B parallel to the crystal c axis show that 89Y at T < 20
K relaxes due to fluctuating magnetic field created only by Ho13+ transitions
between the ground and the first excited Zeeman sublevels of the 5I8 multiplet.",1712.03041v1
2018-03-22,Transient dynamics of strongly coupled spin vortex pairs: effects of anharmonicity and resonant excitation on inertial switching,"Spin vortices in magnetic nanopillars are used as GHz oscillators, with
frequency however essentially fixed in fabrication. We demonstrate a model
system of a two-vortex nanopillar, in which the resonance frequency can be
changed by an order of magnitude, without using high dc magnetic fields. The
effect is due to switching between the two stable states of the vortex pair,
which we show can be done with low-amplitude fields of sub-ns duration. We
detail the relevant vortex-core dynamics and explain how field anharmonicity
and phase control can be used to enhance the performance.",1803.08413v1
2018-02-22,Chaotic dynamics in spin-vortex pairs,"We report on spin-vortex pair dynamics measured at temperatures low enough to
suppress stochastic core motion, thereby uncovering the highly non-linear
intrinsic dynamics of the system. Our analysis shows that the decoupling of the
two vortex cores is resonant and can be enhanced by dynamic chaos. We detail
the regions of the relevant parameter space, in which the various mechanisms of
the resonant core-core dynamics are activated. We show that the presence of
chaos can reduce the thermally-induced spread in the switching time by up to
two orders of magnitude.",1802.08271v1
2020-04-01,Interaction-induced current asymmetries in resonant transport through interacting quantum-dot spin valves revealed by iterative summation of path integrals,"Resonant tunneling of electrons between two ferromagnets and a quantum dot in
the presence of an externally applied magnetic field reveals a strong gate
dependence in the linear and nonlinear bias regime. This gate dependence
originates from the interplay between Coulomb interactions and spin-dependent
hybridization between the quantum dot and the leads. To take into account
Coulomb interaction strengths of the same order of magnitude as the external
magnetic field and the hybridization strength we adopt the numerically exact
iterative summation of path integrals (ISPI).",2004.00432v1
2016-03-17,Theoretical interpretation of a spin-two diphoton excess,"A spin-two resonance would have couplings to the SM, suppressed via
higher-dimensional operators. Therefore, a sizeable cross-section would
indicate that the scale of additional new phenomena cannot be too far above the
750 GeV mark. Below I present some theoretical arguments to place the resonance
in a wider framework: a manifestation of new extra-dimensions, or a glueball of
a new strong sector. In each case, I identify some conditions the UV theory
must satisfy to accommodate other experimental bounds. Based on those, I draw
correlations with associated phenomena we expect to find in future searches.",1603.05574v1
2021-04-28,Simulation of multiple-quantum NMR dynamics of spin dimer on quantum computer,"Dymanics of spin dimers in multiple quantum NMR experiment is studied on the
5-qubit superconducting quantum processor of IBM {Quantum Experience} for the
both {pure} ground and thermodynamic equilibrium (mixed) initial states. The
work can be considered as a first step towards an application of quantum
computers to solving problems of magnetic resonance. This article is dedicated
to Prof. Klaus M\""obius and Prof. Kev Salikhov on the occasion of their 85th
birthdays.",2104.13777v1
2021-08-09,Temperature Measurement Based on Electron Spin Resonance of Magnetic Nanoparticles,"Magnetic nanoparticles (MNPs) have excellent magnetic-temperature
characteristic. However, current temperature measurement based on MNPs is
interfered by concentration. Utilizing the electron spin resonance (ESR), we
propose a highly sensitive temperature measurement method without concentration
coupling. The anisotropic field is affected by temperature, thus affecting the
g-value. The influence of the MNP concentration, size, and the data analysis
method on temperature estimation are studied. The optimal temperature
sensitivity is achieved with 15-nm MNPs while Gaussian smoothing method allows
an optimal accuracy at Fe concentration of 5 mg/ml with a root mean squared
error of 0.07 K.",2108.03797v2
2003-12-30,Direct perturbation theory on the shift of Electron Spin Resonance,"We formulate a direct and systematic perturbation theory on the shift of the
main paramagnetic peak in Electron Spin Resonance, and derive a general
expression up to second order. It is applied to one-dimensional XXZ and
transverse Ising models in the high field limit, to obtain explicit results
including the polarization dependence for arbitrary temperature.",0312698v2
2019-07-29,Ground state cooling of nanomechanical resonators by electron transport,"We discuss two theoretical proposals for controlling the nonequilibrium
steady state of nanomechanical resonators using quantum electronic transport.
Specifically?, we analyse two approaches to achieve the ground-state cooling of
the mechanical vibration coupled to a quantum dot embedded between (i)
spin-polarised contacts or (ii) a normal metal and a superconducting contact.
Assuming a suitable coupling between the vibrational modes and the charge or
spin of the electrons in the quantum dot, we show that ground-state cooling of
the mechanical oscillator is within the state of the art for suspended carbon
nanotube quantum dots operating as electromechanical devices.",1907.12397v1
2019-08-03,Resonant inelastic x-ray scattering study of $α$-RuCl$_3$: a progress report,"Ru M$_3$-edge resonant inelastic x-ray scattering (RIXS) measurements of
RuCl$_3$ with 27 meV resolution reveals a spin-orbit exciton without noticeable
splitting. We extract values for the spin-orbit coupling constant
($\lambda=154\pm2$ meV) and trigonal distortion field energy
($\left|\Delta\right|<65$ meV) which support the $j_{\rm eff}=1/2$ nature of
RuCl$_3$. We demonstrate the feasibility of M-edge RIXS for $4d$ systems, which
allows ultra high-resolution RIXS of $4d$ systems until instrumentation for
L-edge RIXS improves.",1908.01190v1
2020-07-10,The determination of the spin and parity of a vector-vector system,"We present a construction of the reaction amplitude for the inclusive
production of a resonance decaying to a pair of identical vector particles such
as $J/\psi J/\psi$, $\rho\rho$, $\phi\phi$. The method provides the possibility
of determining the spin and parity of a resonance in a model-independent way.
The methodology is demonstrated using the Standard Model decay of the Higgs
boson to four leptons and through angular correlations in the production and
decays of $J/\psi$ pairs.",2007.05501v2
2021-05-03,Anisotropy-Exchange Resonance as a Mechanism for Entangled State Switching,"We explore the three-particle spin model of an $S_{1}=\frac{1}{2}$ particle
(e.g. a stationary electron) interacting with two spin-coupled $S_{\text{2,3}}$
particles with exchange coupling and magnetic anisotropy. We find that in the
case of $S_{2,3}=1$ particles, the coupled particle entanglement states can be
prepared, controlled, and read by the $S_{1}$ particle. We also find that for
particular resonance conditions of the magnetic anisotropy strength $D$ and
exchange coupling strength $J$, the entanglement state switching behavior is
maximized and is robust against a range of anisotropic application of the
exchange coupling.",2105.01126v1
2021-05-05,Zero-field 29Si nuclear magnetic resonance signature of helimagnons in MnSi,"The low temperature dependence of the nuclear magnetic resonance frequency
and spin-lattice relaxation rate measured in the chiral magnet MnSi by Yasuoka
and coworkers [J. Phys. Soc. Jpn. 85, 073701 (2016)] is interpreted in terms of
helimagnon excitations. The theoretically predicted gapless and anisotropic
dispersion relation which is probed at extremely small energy is experimentally
confirmed. Whenever comparison is possible, the results are found
quantitatively consistent with those of the inelastic neutron scattering and
muon spin rotation and relaxation techniques. Further studies are suggested.",2105.02194v1
2022-01-09,Properties of Gamow-Teller and charge-exchange giant spin-monopole resonances in medium-heavy closed-shell parent nuclei: a semi-microscopic description,"The basic version of the semi-microscopic particle-hole dispersive optical
model is implemented to describe main properties of the Gamow-Teller and
charge-exchange giant spin-monopole resonances in medium-heavy closed-shell
parent nuclei. Calculation results obtained for $^{48}Ca$, $^{90}Zr$,
$^{132}Sn$, and $^{208}Pb$ are compared with available experimental data.",2201.02965v2
2022-06-11,Multi-state interferometric measurement of nonlinear AC Stark shift,"We demonstrate measurement of quadratic AC Stark shifts between Zeeman
sublevels in an $^{87}$Rb Bose--Einstein condensate using a multi-state atomic
interferometer. The interferometer can detect a quadratic shift without being
affected by relatively large state-independent shifts, thereby improving the
measurement precision. We measure quadratic shifts in the total spin $F = 2$
state due to the light being near-resonant to the D$_1$ line. The agreement
between the measured and theoretical detuning dependences of the quadratic
shifts confirms the validity of the measurement. We also present results on the
suppression of nonlinear spin evolution using near-resonant dual-color light
pulses with opposite quadratic shifts.",2206.05465v1
2023-03-14,Magnetic and Structural Properties of 5d Osmate Double Perovskites Probed by Nuclear Magnetic Resonance,"The combined effect of electronic correlation and strong
spin-orbit-coupling(SOC) can give rise to a variety of exotic quantum phases.
Double perovskites provide a simple structure to study the spin-orbit-lattice
entangled states. In this thesis, focusing on the 5d osmate double perovskite
system, we conduct a combination of work including theoretical model
simulation, first-principle calculation, and nuclear magnetic resonance
experiments to understand the fundamental physical properties of this material
system.",2303.07573v1
2023-09-27,Regulating spin dynamics in magnetic nanomaterials,"Magnetic nanomaterials can be used in the construction of devices for
information processing and memory storage. For this purpose, they have to enjoy
two contradictory properties, from one side being able of keeping for long time
magnetization frozen, hence information stored, and from the other side
allowing for quick change of magnetization required for fast erasing of memory
and rewriting new information. Methods of resolving this dilemma are suggested
based on triggering resonance, dynamic resonance tuning, and on quadratic
Zeeman effect. These methods make it possible to realize effective regulation
of spin dynamics in such materials as magnetic nanomolecules and magnetic
nanoclusters.",2309.15568v1
2024-03-27,The effect of cutoff dependence on heavy quark spin symmetry partners,"Hadron spectroscopy is revealed by observing heavy resonances. Among various
explanations of the internal structure of these hadronic states, hadronic
molecules play a unique role. For hadronic molecules, which are associated with
meson-meson or meson-baryon interactions, the $\Lambda$ cutoff is a significant
factor in determining the composite states' binding energies and overall
properties. The cutoff becomes important when it comes to the location of
hadronic molecules' masses because it influences the predictions. From this
perspective, in the light of cutoff dependency, heavy quark spin partners of
near-threshold the $\chi_{c0}(3915)$, $\chi_{c1}(3872)$, $P_c(4440)$, and
$P_c(4457)$ resonances, which are considered as hadronic molecules, are
examined.",2403.18633v1
1992-04-10,Spin Singlet Quantum Hall Effect and Nonabelian Landau-Ginzburg Theory,"We show that the Halperin-Haldane SQHE wave function can be written in the
form of a product of a wave function for charged semions in a magnetic field
and a wave function for the Chiral Spin Liquid of neutral spin-$\12$ semions.
We introduce field-theoretic model in which the electron operators are
factorized in terms of charged spinless semions (holons) and neutral spin-$\12$
semions (spinons). Broken time reversal symmetry and short ranged spin
correlations lead to $SU(2)_{k=1}$ Chern-Simons term in Landau-Ginzburg action
for SQHE phase. We construct appropriate coherent states for SQHE phase and
show the existence of $SU(2)$ valued gauge potential. This potential appears as
a result of ``spin rigidity"" of the ground state against any displacements of
nodes of wave function from positions of the particles and reflects the
nontrivial monodromy in the presence of these displacements. We argue that
topological structure of $SU(2)_{k=1}$ Chern-Simons theory unambiguously
dictates {\it semion} statistics of spinons.",9204002v1
1994-07-08,$J_1-J_2$ Quantum Heisenberg Antiferromagnet: Improved Spin-Wave Theories Versus Exact-Diagonalization Data,"We reconsider the results cocerning the extreme-quantum $S=1/2$
square-lattice Heisenberg antiferromagnet with frustrating diagonal couplings
($J_1-J_2$ model) drawn from a comparison with exact-diagonalization data. A
combined approach using also some intrinsic features of the self-consistent
spin-wave theory leads to the conclusion that the theory strongly overestimates
the stabilizing role of quantum flutcuations in respect to the N\'{e}el phase
in the extreme-quantum case $S=1/2$. On the other hand, the analysis implies
that the N\'{e}el phase remains stable at least up to the limit $J_{2}/J_{1} =
0.49$ which is pretty larger than some previous estimates. In addition, it is
argued that the spin-wave ansatz predicts the existence of a finite range
($J_{2}/J_{1}<0.323$ in the linear spin-wave theory) where the Marshall-Peierls
sigh rule survives the frustrations.",9407042v1
1996-08-21,The effect of magnetic dipolar interactions on the interchain spin wave dispersion in CsNiF_3,"Inelastic neutron scattering measurements were performed on the ferromagnetic
chain system CsNiF_3 in the collinear antiferromagnetic ordered state below T_N
= 2.67K. The measured spin wave dispersion was found to be in good agreement
with linear spin wave theory including dipolar interactions. The additional
dipole tensor in the Hamiltonian was essential to explain some striking
phenomena in the measured spin wave spectrum: a peculiar feature of the
dispersion relation is a jump at the zone center, caused by strong dipolar
interactions in this system. The interchain exchange coupling constant and the
planar anisotropy energy were determined within the present model to be J'/k_B
= -0.0247(12)K and A/k_B = 3.3(1)K. This gives a ratio J/J' \approx 500, using
the previously determined intrachain coupling constant J/k_B = 11.8$. The small
exchange energy J' is of the same order as the dipolar energy, which implies a
strong competition between the both interactions.",9608085v1
1999-03-15,Interplay of spin density wave and superconductivity with different pairing symmetry,"A model study for the coexistence of the spin density wave and
superconductivity is presented. With reference to the recent angle resolved
photo emmission experimental data in high T_c cuprates, presence of the nested
pieces of bands is assumed. The single band Hubbard model, therefore, when
treated within the Hatree-Fock mean field theory leads to a spin density wave
(SDW) ground state. The superconductivity (SC) is assumed to be due to a
generalised attractive potential with a separable form without specifying to
any particular origin. It therefore allows a comparative study of the
coexistence of superconductivity of different order parameter symmetry with the
spin density wave state. We find that the phase diagram, comprising of the
amplitudes of the respective gaps (SC and SDW) Vs. band filling resembles to
that of the high T_c cuprates only when the order parameter of the
superconducting phase has d-wave symmetry. Thermal variation of different order
parameters (e.g, SC and SDW) also show interesting coexistence and reentrance
behaviors that are consistent with experimental observations, specially for the
borocarbides.",9903234v1
2001-02-04,Spin wave specific heat in quasiperiodic Fibonacci structures,"The energy spectra of a variety of collective modes on quasiperiodic
structures exhibit a complex fractal profile. Among the modes that have
attracted particular attention in this context, are the spin wave spectra of
quasiperiodic magnetic multilayers that obey a substitutional sequence of the
Fibonacci type. They are described within the framework of the Heisenberg
theory. In order to have a deep insight on the relevant thermodynamical
implications of the above mentioned energy spectra's fractal profile, we have
performed analytical and numerical calculations of the spin wave specific heat
associated with successive hierarchical sequences of the Fibonacci
quasiperiodic structures. The spectra show interesting oscillatory behavior in
the low-temperature region, which can be traced back to the spin wave's
self-similar energy spectrum.",0102046v1
2001-02-07,Interplay between spin-density-wave and superconducting states in quasi-one-dimensional conductors,"The interference between spin-density-wave and superconducting instabilities
in quasi-one-dimensional correlated metals is analyzed using the
renormalization group method. At the one-loop level, we show how the
interference leads to a continuous crossover from a spin-density-wave state to
unconventional superconductivity when deviations from perfect nesting of the
Fermi surface exceed a critical value. Singlet pairing between electrons on
neighboring stacks is found to be the most favorable symmetry for
superconductivity. The consequences of non uniform spin-density-wave pairing on
the structure of phase diagram within the crossover region is also discussed.",0102139v1
2001-06-18,Low-frequency dynamics of disordered XY spin chains and pinned density waves: from localized spin waves to soliton tunneling,"A long-standing problem of the low-energy dynamics of a disordered XY spin
chain is re-examined. The case of a rigid chain is studied where the quantum
effects can be treated quasiclassically. It is shown that as the frequency
decreases, the relevant excitations change from localized spin waves to
two-level systems to soliton-antisoliton pairs. The linear-response correlation
functions are calculated. The results apply to other periodic glassy systems
such as pinned density waves, planar vortex lattices, stripes, and disordered
Luttinger liquids.",0106350v3
2001-10-16,Analytical and numerical study of hardcore bosons in two dimensions,"We study various properties of bosons in two dimensions interacting only via
onsite hardcore repulsion. In particular, we use the lattice spin-wave
approximation to calculate the ground state energy, the density, the condensate
density and the superfluid density in terms of the chemical potential. We also
calculate the excitation spectrum, $\omega({\bf k})$. In addition, we performed
high precision numerical simulations using the stochastic series expansion
algorithm. We find that the spin-wave results describe extremely well the
numerical results over the {\it whole} density range $0\leq \rho \leq 1$. We
also compare the lattice spin-wave results with continuum results obtained by
summing the ladder diagrams at low density. We find that for $\rho \leq 0.1$
there is good agreement, and that the difference between the two methods
vanishes as $\rho^2$ for $\rho \to 0$. This offers the possibility of obtaining
precise continuum results by taking the continuum limit of the spin-wave
results for all densities. Finaly, we studied numerically the finite
temperature phase transition for the entire density range and compared with low
density predictions.",0110314v1
2002-02-02,Spin Wave Propagation in the Domain State of a Random Field Magnet,"Inelastic neutron scattering with high wave-vector resolution has
characterized the propagation of transverse spin wave modes near the
antiferromagnetic zone center in the metastable domain state of a random field
Ising magnet. A well-defined, long wavelength excitation is observed despite
the absence of long-range magnetic order. Direct comparisons with the spin wave
dispersion in the long-range ordered antiferromagnetic state reveal no
measurable effects from the domain structure. This result recalls analogous
behavior in thermally disordered anisotropic spin chains but contrasts sharply
with that of the phonon modes in relaxor ferroelectrics.",0202038v2
2005-04-04,Theory of Spin-Wave Frequency Gaps in 3D Magnonic Crystals. Application to Manganites,"his study is an investigation of spin wave spectrum in macrostructures
composed of two ferromagnetic materials and showing a 3D periodicity: spherical
ferromagnetic grains disposed in the nodes of a 3D crystal lattice are embedded
in a matrix with different ferromagnetic properties. Frequency ranges forbidden
to spin wave propagation are found in the calculated magnonic spectra. Both the
position and the width of the gaps are found to depend on the magnetic
(exchange and magnetization) contrasts in the composite material, as well as on
its structural parameters (filling fraction, crystal lattice type). Having
applied our theory to interpretation of the existence of a spin wave gap in
doped manganites, recently revealed in neutron scattering experiments by S.
Hennion {\em et al.}, we obtained a good (though approximate) quantitative
agreement with the experimental results. A working hypothesis is proposed on
this basis, supposing that certain manganites can be treated as natural 3D
magnonic crystals.",0504073v1
2005-05-16,Spin Waves in a Periodically Layered Magnetic Nanowire,"We report a simple theoretical derivation of the spectrum and damping of spin
waves in a cylindrical periodically structured magnetic nanowire (cylindrical
magnonic crystal) in the ""effective medium"" approximation. The dependence of
the ""effective"" magnetic parameters upon the individual layer parameters is
shown to be different from the arithmetic average over the volume of the
superlattice. The formulae that are obtained can be applied firstly in the
description of spin wave dispersion in the first allowed band of the structure;
and secondly in the design of a magnonic crystal with band-gaps in an arbitrary
part of the spin wave spectrum.",0505382v1
2005-11-19,Measurement of spin waves and activation volumes in superparamagnetic Fe films on GaAs(100),"Spin wave frequencies are observed in ultra-thin Fe/GaAs(100) films at
temperatures where the spontaneous zero field magnetization is zero. The films
exhibit good cyrstalline structure, and the effect of magnetic anisotropies is
apparent even though no zero field spin wave energy gap exists. An analysis is
given in terms of a superparamagnetic model in which the film is treated as a
network of non-interacting single domain magnetic islands. A spin wave analysis
provides a means to separate measured values of anisotropy parameters from
products involving anisotropy and island volume. In this way, a measure of the
activation volume associated with superparamagnetic islands is obtained for
different Fe film thicknesses. Results suggest that the island lateral area
increases with increasing film thickness.",0511482v1
1992-02-08,Spin Singlet Quantum Hall Effect and Nonabelian Landau-Ginzburg Theory,"In this paper we present a theory of Singlet Quantum Hall Effect (SQHE). We
show that the Halperin-Haldane SQHE wave function can be written in the form of
a product of a wave function for charged semions in a magnetic field and a wave
function for the Chiral Spin Liquid of neutral spin-$\12$ semions. We introduce
field-theoretic model in which the electron operators are factorized in terms
of charged spinless semions (holons) and neutral spin-$\12$ semions (spinons).
Broken time reversal symmetry and short ranged spin correlations lead to
$SU(2)_{k=1}$ Chern-Simons term in Landau-Ginzburg action for SQHE phase. We
construct appropriate coherent states for SQHE phase and show the existence of
$SU(2)$ valued gauge potential. This potential appears as a result of ``spin
rigidity"" of the ground state against any displacements of nodes of wave
function from positions of the particles and reflects the nontrivial monodromy
in the presence of these displacements.",9202029v1
2006-11-10,Eikonal Approximation in AdS/CFT: Conformal Partial Waves and Finite N Four-Point Functions,"We introduce the impact-parameter representation for conformal field theory
correlators of the form A ~ < O_1 O_2 O_1 O_2 >. This representation is
appropriate in the eikonal kinematical regime, and approximates the conformal
partial-wave decomposition in the limit of large spin and dimension of the
exchanged primary. Using recent results on the two-point function < O_1 O_1
>_{shock} in the presence of a shock wave in Anti-de Sitter, and its relation
to the discontinuity of the four-point amplitude A across a kinematical
branch-cut, we find the high spin and dimension conformal partial- wave
decomposition of all tree-level Anti-de Sitter Witten diagrams. We show that,
as in flat space, the eikonal kinematical regime is dominated by the T-channel
exchange of the massless particle with highest spin (graviton dominance). We
also compute the anomalous dimensions of the high-spin O_1 O_2 composites.
Finally, we conjecture a formula re-summing crossed-ladder Witten diagrams to
all orders in the gravitational coupling.",0611123v1
2005-09-30,Macroscopic quantum information channel via the polarization-sensitive interaction between the light and spin subsystems,"We discuss the quantum information channel, which is based on coherent and
polarization sensitive interaction of light and atomic spin waves. We show that
the joint Heisenberg dynamics of the polarization Stokes components of light
and of the angular momenta of atoms has a wave nature and can be properly
described in terms of the macroscopic polariton-type spin wave created in the
sample. The principles of the quantum memory and readout protocols via the wave
coupling of the output time modes in the light subsystem and the output spatial
modes in the spin subsystem are demonstrated.",0509220v1
2007-04-05,Partially disordered state near ferromagnetic transition in MnSi,"The polarized neutron scattering in helimagnetic MnSi at low $T$ reveals
existence of a partially disordered chiral state at ambient pressure in the
magnetic field applied along $<111>$ axis below the first order transition to
the non-chiral ferromagnetic state. This unexpected phenomenon is explained by
the analysis of the spin-wave spectrum. We demonstrate that the square of the
spin-wave gap becomes negative under magnetic field applied along $<111>$ and
$<110>$ but not along the $<100>$ direction. It is a result of competition
between the spin-wave interaction and cubic anisotropy. This negative sign
means an instability of the spin wave spectrum for the helix and leads to a
destruction of the helical order, giving rise to the partially disordered state
below the first order ferromagnetic transition.",0704.0683v1
2007-07-09,"Comment on ""Multiferroicity Induced by Dislocated Spin-Density Waves""","I show that the claims in Phys. Rev. Lett. 98, 257602 by Betouras et al
concerning YMn2O5 are incorect.",0707.1327v1
2007-11-16,Spin waves and local magnetizations on the Penrose tiling,"We consider a Heisenberg antiferromagnet on the Penrose tiling, a
quasiperiodic system having an inhomogeneous Neel-ordered ground state. Spin
wave energies and wavefunctions are studied in the linear spin wave
approximation. A linear dispersion law is found at low energies, as in other
bipartite antiferromagnets, with an effective spin wave velocity lower than in
the square lattice. Spatial properties of eigenmodes are characterized in
several different ways. At low energies, eigenstates are relatively extended,
and show multifractal scaling. At higher energies, states are more localized,
and, depending on the energy, confined to sites of a specified coordination
number. The ground state energy of this antiferromagnet, and local staggered
magnetizations are calculated. Perpendicular space projections are presented in
order to show the underlying simplicity of this ""complex"" ground state. A
simple analytical model, the two-tier Heisenberg star, is presented to explain
the staggered magnetization distribution in this antiferromagnetic system.",0711.2670v3
2007-12-18,Dynamics Of Proton Spin : Role Of $qqq$ Force,"The analytic structure of the $qqq$ wave function, obtained recently in the
high momentum regime of QCD, is employed for the formulation of baryonic
transition amplitudes via quark loops. A new aspect of this study is the role
of a direct ($Y$-shaped, Mercedes-Benz type) $qqq$ force in generating the
$qqq$ wave function. The dynamics is that of a Salpeter-like equation (3D
support for the kernel) formulated covariantly on the light front, a la
Markov-Yukawa Transversality Principle (MYTP) which warrants a 2-way
interconnection between the 3D and 4D Bethe-Salpeter (BSE) forms for 2 as well
as 3 fermion quarks. The dynamics of this 3-body force shows up through a
characteristic singularity in the hypergeometric differential equation for the
3D wave function $\phi$, corresponding to a $negative$ eigenvalue of the spin
operator $i \sigma_1.\sigma_2\times \sigma_3$ which is an integral part of the
$qqq$ force. As a first application of this wave function to the problem of the
proton spin anomaly, the two-gluon contribution to the anomaly yields an
estimate of the right sign, although somewhat smaller in magnitude.
  Keywords: 3bodyforce; proton-spin; 2gluon anomaly; fractional correction
$\theta$",0712.2896v1
2008-04-04,Modification of the thermal spin-wave spectrum in a Ni81Fe19 stripe by a domain wall,"The thermal spin-wave distribution in a Ni81Fe19 stripe with an asymmetric
transverse domain wall has been investigated using Brillouin light scattering
microscopy. Clear evidence has been found that the existence of the domain wall
influences the spin-wave distribution of the thermal modes. The thermal
spin-wave modes are quantized due to the confinement in radial direction. They
vanish near the domain wall and a new mode evolves inside this complex domain
wall structure. This effect is attributed to a change of the effective internal
field in the domain wall region. The experimental results agree well with
static and dynamic micromagnetic simulations.",0804.0734v2
2008-11-03,Dispersion in magnetostatic CoTaZr spin wave-guides,"Magnetostatic spin wave dispersion and loss are measured in micron scale spin
wave-guides in ferromagnetic, metallic CoTaZr. Results are in good agreement
with model calculations of spin wave dispersion and up to three different modes
are identified. Attenuation lengths of the order of 3 microns are several of
orders of magnitude shorter than that predicted from eddy currents in these
thin wires.",0811.0350v2
2009-01-19,Chiral asymmetry of the spin-wave spectra in ultrathin magnetic films,"We raise the possibility that the chiral degeneracy of the magnons in
ultrathin films can be lifted due to the presence of Dzyaloshinskii-Moriya
interactions. By using simple symmetry arguments, we discuss under which
conditions such a chiral asymmetry occurs. We then perform relativistic first
principles calculations for an Fe monolayer on W(110) and explicitly reveal the
asymmetry of the spin-wave spectrum in case of wave-vectors parallel to the
(001) direction. Furthermore, we quantitatively interpret our results in terms
of a simplified spin-model by using calculated Dzyaloshinskii-Moriya vectors.
Our theoretical prediction should inspire experiments to explore the asymmetry
of spin-waves, with a particular emphasis on the possibility to measure the
Dzyaloshinskii-Moriya interactions in ultrathin films.",0901.2671v1
2009-02-13,Anomalous spin-waves and the commensurate-incommensurate magnetic phase transition in LiNiPO4,"Detailed spin-wave spectra of magneto-electric LiNiPO4 have been measured by
neutron scattering at low temperatures in the commensurate (C)
antiferromagnetic (AF) phase with ordering temperature 20.8 K. An anomalous
low-energy mode is observed at the modulation vector of the incommensurate (IC)
AF phase appearing above the 20.8 K. A linear spin-wave model based on
Heisenberg exchange couplings and single ion anisotropies accounts for all the
observed spin-wave dispersions and intensities. Along the b axis an unusually
strong next-nearest-neighbor AF coupling competes with the dominant
nearest-neighbor AF exchange interaction and causes the IC structure.",0902.2288v1
2009-06-19,Bounding the mass of the graviton with gravitational waves: Effect of spin precessions in massive black hole binaries,"Observations of gravitational waves from massive binary black hole systems at
cosmological distances can be used to search for a dependence of the speed of
propagation of the waves on wavelength, and thereby to bound the mass of a
hypothetical graviton. We study the effects of precessions of the spins of the
black holes and of the orbital angular momentum on the process of parameter
estimation using matched filtering of gravitational-wave signals vs.
theoretical template waveforms. For the proposed space interferometer LISA, we
show that precessions, and the accompanying modulations of the gravitational
waveforms, are effective in breaking degeneracies among the parameters being
estimated, and effectively restore the achievable graviton-mass bounds to
levels obtainable from binary inspirals without spin. For spinning, precessing
binary black hole systems of equal masses (10^6 solar masses) at 3 Gpc, the
bounds on the graviton Compton wavelength achievable are of the order of 5 X
10^{16} km.",0906.3602v2
2009-07-22,Fluctuating spin density waves in metals,"Recent work has used a U(1) gauge theory to describe the physics of Fermi
pockets in the presence of fluctuating spin density wave order. We generalize
this theory to an arbitrary band structure and ordering wavevector. The
transition to the large Fermi surface state, without pockets induced by local
spin density wave order, is described by embedding the U(1) gauge theory in a
SU(2) gauge theory. The phase diagram of the SU(2) gauge theory shows that the
onset of spin density wave order in the Fermi liquid occurs either directly, in
the framework discussed by Hertz, or via intermediate non-Fermi liquid phases
with Fermi surfaces of fractionalized excitations. We discuss application of
our results to the phase diagram of the cuprates.",0907.3732v2
2009-08-17,Demonstration of atomic frequency comb memory for light with spin-wave storage,"We present a light-storage experiment in a praseodymium-doped crystal where
the light is mapped onto an inhomogeneously broadened optical transition shaped
into an atomic frequency comb. After absorption of the light the optical
excitation is converted into a spin-wave excitation by a control pulse. A
second control pulse reads the memory (on-demand) by reconverting the spin-wave
excitation to an optical one, where the comb structure causes a photon-echo
type rephasing of the dipole moments and directional retrieval of the light.
This combination of photon echo and spin-wave storage allows us to store
sub-microsecond (450ns) pulses for up to 20 microseconds. The scheme has a high
potential for storing multiple temporal modes in the single photon regime,
which is an important resource for future long-distance quantum communication
based on quantum repeaters.",0908.2309v2
2009-10-04,Zero temperature phases of the frustrated J1-J2 antiferromagnetic spin-1/2 Heisenberg model on a simple cubic lattice,"At zero temperature magnetic phases of the quantum spin-1/2 Heisenberg
antiferromagnet on a simple cubic lattice with competing first and second
neighbor exchanges (J1 and J2) is investigated using the non-linear spin wave
theory. We find existence of two phases: a two sublattice Neel phase for small
J2 (AF), and a collinear antiferromagnetic phase at large J2 (CAF). We obtain
the sublattice magnetizations and ground state energies for the two phases and
find that there exists a first order phase transition from the AF-phase to the
CAF-phase at the critical transition point, pc = 0.28. Our results for the
value of pc are in excellent agreement with results from Monte-Carlo
simulations and variational spin wave theory. We also show that the quartic 1/S
corrections due spin-wave interactions enhance the sublattice magnetization in
both the phases which causes the intermediate paramagnetic phase predicted from
linear spin wave theory to disappear.",0910.0638v2
2009-11-10,Spin-wave propagation in a microstructured magnonic crystal,"Transmission of microwave spin waves through a microstructured magnonic
crystal in the form of a permalloy waveguide of a periodically varying width
was studied experimentally and theoretically. The spin wave characteristics
were measured by spatially-resolved Brillouin light scattering microscopy. A
rejection frequency band was clearly observed. The band gap frequency was
controlled by the applied magnetic field. The measured spin-wave intensity as a
function of frequency and propagation distance is in good agreement with a
model calculation.",0911.1920v1
2010-03-31,Magnonic Crystal with Two-Dimensional Periodicity as a Waveguide for Spin Waves,"We describe a simple method of including dissipation in the spin wave band
structure of a periodic ferromagnetic composite, by solving the Landau-Lifshitz
equation for the magnetization with the Gilbert damping term. We use this
approach to calculate the band structure of square and triangular arrays of Ni
nanocylinders embedded in an Fe host. The results show that there are certain
bands and special directions in the Brillouin zone where the spin wave lifetime
is increased by more than an order of magnitude above its average value. Thus,
it may be possible to generate spin waves in such composites decay especially
slowly, and propagate especially large distances, for certain frequencies and
directions in ${\bf k}$-space.",1003.6092v1
2010-06-26,Spin-Orbit Coupled Spinor Bose-Einstein Condensates,"An effective spin-orbit coupling can be generated in cold atom system by
engineering atom-light interactions. In this letter we study spin-1/2 and
spin-1 Bose-Einstein condensates with Rashba spin-orbit coupling, and find that
the condensate wave function will develop non-trivial structures. From
numerical simulation we have identified two different phases. In one phase the
ground state is a single plane wave, and often we find the system splits into
domains and an array of vortices plays the role as domain wall. In this phase,
time-reversal symmetry is broken. In the other phase the condensate wave
function is a standing wave and it forms spin stripe. The transition between
them is driven by interactions between bosons. We also provide an analytical
understanding of these results and determines the transition point between the
two phases.",1006.5148v4
2010-07-03,"Second-order quantum corrections for the frustrated, spatially anisotropic, spin-1/2 Heisenberg antiferromagnet on a square lattice","The effects of quantum fluctuations due to directional anisotropy and
frustration between nearest neighbors and next-nearest neighbors of the quantum
spin-1/2 Heisenberg antiferromagnet on a square lattice are investigated using
spin-wave expansion. We have calculated the spin-wave energy dispersion in the
entire Brillouin zone, renormalized spin-wave velocities, and the magnetization
up to second order in 1/S expansion for the antiferromagnetic Neel and
collinear antiferromagnetic stripe phases. It is shown that the second-order
corrections become significant with increase in frustration. With these
corrections magnetizations and spin-wave velocities for both the phases become
zero at the quantum critical points as expected from other numerical and
analytical methods. We have shown that the transition between the two ordered
phases are always separated by the disordered paramagnetic phase.",1007.0502v4
2010-09-28,The magnonic limit of domain wall propagation in ferromagnetic nanotubes,"We report a study on the field-driven propagation of vortex-like domain walls
in ferromagnetic nanotubes. This particular geometry gives rise to a special
feature of the static wall configuration, which significantly influences its
dynamics. Unlike domain walls in flat strips, the left-right symmetry of domain
wall propagation is broken. Furthermore, the domain wall velocity is not
limited by the Walker breakdown. Under sufficiently large magnetic fields, the
domain wall velocity reaches the velocity of spin waves (about 1000 m/s) and is
thereafter connected with a direct emission of spin waves. The moving domain
wall maintains its main structure but has characteristic spin-wave tails
attached. The spatial profile of this topological soliton is determined by the
spin-wave dispersion.",1009.5552v1
2011-07-07,Method to characterize spinons as emergent elementary particles,"We develop a technique to directly study spinons (emergent spin S = 1/2
particles) in quantum spin models in any number of dimensions. The size of a
spinon wave packet and of a bound pair (a triplon) are defined in terms of
wave-function overlaps that can be evaluated by quantum Monte Carlo
simulations. We show that the same information is contained in the spin-spin
correlation function as well. We illustrate the method in one dimension. We
confirm that spinons are well defined particles (have exponentially localized
wave packet) in a valence-bond-solid state, are marginally defined (with
power-law shaped wave packet) in the standard Heisenberg critical state, and
are not well defined in an ordered N\'eel state (achieved in one dimension
using long-range interactions).",1107.1439v2
2011-08-16,Magnetic rogue wave in a perpendicular anisotropic ferromagnetic nanowire with spin-transfer torque,"We present the current controlled motion of dynamic soliton embedded in spin
wave background in ferromagnetic nanowire. With the stronger breather character
we get the novel magnetic rogue wave and clarify its formation mechanism. The
generation of magnetic rogue wave is mainly arose from the accumulation of
energy and magnons toward to its central part. We also observe that the
spin-polarized current can control the exchange rate of magnons between
envelope soliton and background, and the critical current condition is obtained
analytically. Even more interesting is that the spin-transfer torque plays the
completely opposite role for the cases of below and above the critical value.",1108.3252v2
2011-10-26,SpinWaves in Ferromagnetic Dots 2D Honeycomb Lattice Stripes,"In this work, the spin wave calculations were carried out using the
Heisenberg Hamiltonian to study the allowed spin waves of zigzag and armchair
edged stripes for ferromagnetic nanodots arrayed in a 2D honeycomb lattice
\cite{Selim2011}. The Hamiltonian is used to construct the $\mathbf{E}$ matrix
which encodes the exchange flow of magnons in the stripes. It is found that the
allowed spin wave modes are the eigenvalues of the $\mathbf{E}$ matrix and
therefore it is used to study the effects of the stripe width, edge exchange,
the edge uniaxial anisotropy, and impurities on the allowed spin waves of
stripes. The obtained results almost coincide with the results of graphene
nanoribbons described by tight binding Hamiltonian for electronic excitations.
Therefore, we suggest the fabrication of the magnetic counterpart to graphene
as a new technology in the field of spintronic devices and magnetic
applications.",1110.5716v1
2011-12-19,About spin electromagnetic wave-particle with ring singularity,"An axisymmetric space-localized solution of nonlinear electrodynamics is
considered as massive charged particle with spin and magnetic moment. The
appropriate solution for nonlinear electrodynamics with ring singularity is
investigated. In view of this problem the system of toroidal waves in linear
electrodynamics is considered. The problem with boundary conditions on the
singular ring of the toroidal coordinate system is investigated. The boundary
conditions are taken taking into account the conformity between the toroidal
and cylindrical waves on the ring. In this case the singular ring looks like
convolute axis of cylindrical system. The appropriate system of wave modes are
obtained in an integral form with the help of source function.",1112.4437v1
2012-04-16,Topological chiral magnonic edge mode in a magnonic crystal,"Topological phases have been explored in various fields in physics such as
spintronics, photonics, liquid helium, correlated electron system and
cold-atomic system. This leads to the recent foundation of emerging materials
such as topological band insulators, topological photonic crystals and
topological superconductors/superfluid. In this paper, we propose a topological
magnonic crystal which provides protected chiral edge modes for magnetostatic
spin waves. Based on a linearized Landau-Lifshitz equation, we show that a
magnonic crystal with the dipolar interaction acquires spin-wave volume-mode
band with non-zero Chern integer. We argue that such magnonic systems are
accompanied by the same integer numbers of chiral spin-wave edge modes within a
band gap for the volume-mode bands. In these edge modes, the spin wave
propagates in a unidirectional manner without being scattered backward, which
implements novel fault-tolerant spintronic devices.",1204.3349v3
2012-11-20,Microscopic magnetic structuring of a spin-wave waveguide by ion implantation in a Ni(81)Fe(19) layer,"We investigate the spin-wave excitation in microscopic waveguides fabricated
by localized Cr+ ion implantation in a ferromagnetic Ni(81)Fe(19) film. We
demonstrate that spin-wave waveguides can be conveniently made by this
technique. The magnetic patterning technique yields an increased damping and a
reduction in saturation magnetization in the implanted regions that can be
extracted from Brillouin light scattering measurements of the spin-wave
excitation spectra. Furthermore, the waveguide performance as well as the
internal field of the waveguide depend on the doping fluence. The results prove
that localized ion implantation is a powerful tool for the patterning of magnon
spintronic devices.",1211.4786v1
2013-01-29,Single-photon-level optical storage in a solid-state spin-wave memory,"A long-lived quantum memory is a firm requirement for implementing a quantum
repeater scheme. Recent progress in solid-state rare-earth-ion-doped systems
justifies their status as very strong candidates for such systems. Nonetheless
an optical memory based on spin-wave storage at the single-photon-level has not
been shown in such a system to date, which is crucial for achieving the long
storage times required for quantum repeaters. In this letter we show that it is
possible to execute a complete atomic frequency comb (AFC) scheme, including
spin-wave storage, with weak coherent pulses of $\bar{n} = 2.5 \pm 0.6$ photons
per pulse. We discuss in detail the experimental steps required to obtain this
result and demonstrate the coherence of a stored time-bin pulse. We show a
noise level of $(7.1 \pm 2.3)10^{-3}$ photons per mode during storage, this
relatively low-noise level paves the way for future quantum optics experiments
using spin-waves in rare-earth-doped crystals.",1301.6924v1
2013-04-26,A micro-structured ion-implanted magnonic crystal,"We investigate spin-wave propagation in a microstructured magnonic-crystal
waveguide fabricated by localized ion implantation. The irradiation caused a
periodic variation in the saturation magnetization along the waveguide. As a
consequence, the spin-wave transmission spectrum exhibits a set of frequency
bands, where spin-wave propagation is suppressed. A weak modification of the
saturation magnetization by 7% is sufficient to decrease the spin-wave
transmission in the band gaps by a factor of 10. These results evidence the
applicability of localized ion implantation for the fabrication of efficient
micron- and nano-sized magnonic crystals for magnon spintronic applications.",1304.7122v1
2013-05-21,Effect of Hole Shape on Spin-Wave Band Structure in One-Dimensional Magnonic Antidot Waveguide,"We present the possibility of tuning the spin-wave band structure,
particularly the bandgaps in a nanoscale magnonic antidot waveguide by varying
the shape of the antidots. The effects of changing the shape of the antidots on
the spin-wave dispersion relation in a waveguide have been carefully monitored.
We interpret the observed variations by analysing the equilibrium magnetic
configuration and the magnonic power and phase distribution profiles during
spin-wave dynamics. The inhomogeneity in the exchange fields at the antidot
boundaries within the waveguide is found to play a crucial role in controlling
the band structure at the discussed length scales. The observations recorded
here will be important for future developments of magnetic antidot based
magnonic crystals and waveguides.",1305.4812v2
2013-05-28,Magnonic band gaps in waveguides with a periodic variation of the saturation magnetization,"We present a micromagnetic analysis of spin-wave propagation in a magnonic
crystal realized as a permalloy spin-wave waveguide with a spatial periodical
variation of its saturation magnetization. Frequency band gaps were clearly
observed in the spin-wave transmission spectra and their origin is traced back
to an overlap of individual band gaps of the fundamental and the higher order
spin-wave width modes. The control of the depth, width and the position in
frequency and space of the rejection band gaps by the width areas with a
reduced magnetization and by the modulation level, are discussed in this study.",1305.6619v1
2014-05-04,Charge and Spin Density Waves observed through their spatial fluctuations by coherent and simultaneous X-ray diffraction,"Spatial uctuations of spin density wave (SDW) and charge density wave (CDW)
in chromium have been compared by combining coherent and simultaneous X-ray
diffraction experiments. Despite their close relationship, spatial fluctuations
of the spin and of the charge density waves display a very different behavior:
the satellite reflection associated to the charge density displays speckles
while the spin one displays an impressive long-range order. This observation is
hardly compatible with the commonly accepted magneto-elastic origin of CDW in
chromium and is more consistent with a purely electronic scenario where CDW is
the second harmonic of SDW. A BCS model taking into account a second order
nesting predicts correctly the existence of a CDW and explains why the CDW is
more sensitive to punctual defects.",1405.0738v2
2014-11-14,Lifetimes of Magnons in Two-Dimensional Diluted Ferromagnetic Systems,"Spin dynamics in low dimensional magnetic systems has been of fundamental
importance for a long time and has currently received an impetus owing to the
emerging field of nanoelectronics. Knowledge of the spin wave lifetimes, in
particular, can be favorable for future potential applications. We investigate
the low-temperature spin wave excitations in two-dimensional disordered
ferromagnetic systems, with a particular focus on the long wavelength magnon
lifetimes. A semi-analytical Green's functions based approach is used to
determine the dynamical spectral functions, for different magnetic impurity
concentrations, from which the intrinsic linewidth is extracted. We obtain an
unambiguous $q^4$ scaling of the magnon linewidth which is ascribed to the
disorder induced damping of the spin waves, thereby settling a longstanding
unresolved issue on the wave-vector dependence. Our findings are also in good
agreement with previous theoretical studies on Heisenberg ferromagnets.
Additionally, we demonstrate the futility of using the low moments associated
with the spectral densities to evaluate the magnon dispersions and lifetimes.",1411.3876v2
2014-11-26,Pattern Recognition with Magnonic Holographic Memory Device,"In this work, we present experimental data demonstrating the possibility of
using magnonic holographic devices for pattern recognition. The prototype
eight-terminal device consists of a magnetic matrix with micro-antennas placed
on the periphery of the matrix to excite and detect spin waves. The principle
of operation is based on the effect of spin wave interference, which is similar
to the operation of optical holographic devices. Input information is encoded
in the phases of the spin waves generated on the several edges of the magnonic
matrix, while the output corresponds to the amplitude of the inductive voltage
produced by the interfering spin waves on the other side of the matrix. The
level of the output voltage depends on the combination of the input phases as
well as on the internal structure of the magnonic matrix. Experimental data
collected for several magnonic matrixes show the unique output signatures in
which maxima and minima correspond to specific input phase patterns.
Potentially, magnonic holographic devices may provide a higher storage density
compare to the optical counterparts due to a shorter wavelength and
compatibility with conventional electronic devices. The challenges and
shortcoming of the magnonic holographic devices are also discussed.",1411.7082v1
2015-01-16,A solid state spin-wave quantum memory for time-bin qubits,"We demonstrate the first solid-state spin-wave optical quantum memory with
on-demand read-out. Using the full atomic frequency comb scheme in a \PrYSO
crystal, we store weak coherent pulses at the single-photon level with a signal
to noise ratio $> 10$. Narrow-band spectral filtering based on spectral hole
burning in a second \PrYSO crystal is used to filter out the excess noise
created by control pulses to reach an unconditional noise level of $(2.0 \pm
0.3) \times10^{-3}$ photons per pulse. We also report spin-wave storage of
photonic time-bin qubits with conditional fidelities higher than a measure and
prepare strategy, demonstrating that the spin-wave memory operates in the
quantum regime. This makes our device the first demonstration of a quantum
memory for time-bin qubits, with on demand read-out of the stored quantum
information. These results represent an important step for the use of
solid-state quantum memories in scalable quantum networks.",1501.03980v2
2015-05-05,Three-dimensional Character of the Magnetization Dynamics in Magnetic Vortex Structures - Hybridization of Flexure Gyromodes with Spin Waves,"Three-dimensional linear spin-wave eigenmodes of a Permalloy disk having
finite thickness are studied by micromagnetic simulations based on the
Landau-Lifshitz-Gilbert equation. The eigenmodes found in the simulations are
interpreted as linear superpositions (hybridizations) of 'approximate'
three-dimensional eigenmodes, which are the fundamental gyromode $G_0$, the
spin-wave modes and the higher-order gyromodes $G_N$ (flexure modes), the
thickness dependence of which is represented by perpendicular standing spin
waves. This hybridization leads to new and surprising dependencies of the mode
frequencies on the disk thickness. The three-dimensional character of the
eigenmodes is essential to explain the recent experimental results on
vortex-core reversal observed in relatively thick Permalloy disks.",1505.01148v2
2015-06-12,Criticality at the Haldane-insulator charge-density-wave quantum phase transition,"Exploiting the entanglement concept within a matrix-product-state based
infinite density-matrix renormalization group approach, we show that the
spin-density-wave and bond-order-wave ground states of the one-dimensional
half-filled extended Hubbard model give way to a symmetry-protected topological
Haldane state in case an additional alternating ferromagnetic spin interaction
is added. In the Haldane insulator the lowest entanglement level features a
characteristic twofold degeneracy. Increasing the ratio between
nearest-neighbor and local Coulomb interaction $V/U$, the enhancement of the
entanglement entropy, the variation of the charge, spin and neutral gaps, and
the dynamical spin/density response signal a quantum phase transition to a
charge-ordered state. Below a critical point, which belongs to the universality
class of the tricritical Ising model with central charge 7/10, the model is
critical with $c=1/2$ along the transition line. Above this point, the
transition between the Haldane insulator and charge-density-wave phases becomes
first order.",1506.04003v2
2015-06-17,Local spin-density-wave order inside vortex cores in multiband superconductors,"Coexistence of antiferromagnetic order with superconductivity in many
families of newly discovered iron-based superconductors has renewed interest to
this old problem. Due to competition between the two types of order, one can
expect appearance of the antiferromagnetism inside the cores of the vortices
generated by the external magnetic field. The structure of a vortex in type II
superconductors holds significant importance from the theoretical and the
application points of view. Here we consider the internal vortex structure in a
two-band s$_\pm$ superconductor near a spin-density-wave instability. We treat
the problem in a completely self-consistent manner within the quasiclassical
Eilenberger formalism. We study the structure of the s$_\pm$ superconducting
order and magnetic field-induced spin-density-wave order near an isolated
vortex. We examine the effect of this spin-density-wave state inside the vortex
cores on the local density of states.",1506.05440v2
2015-12-04,Polarization dependence of nonlinear wave mixing of spinor polaritons in semiconductor microcavities,"The pseudo-spin dynamics of propagating exciton-polaritons in semiconductor
microcavities are known to be strongly influenced by TE-TM splitting. As a
vivid consequence, in the Rayleigh scattering regime, the TE-TM splitting gives
rise to the optical spin Hall effect (OSHE). Much less is known about its role
in the nonlinear optical regime in which four-wave mixing for example allows
the formation of spatial patterns in the polariton density, such that hexagons
and two-spot patterns are observable in the far field. Here we present a
detailed analysis of spin-dependent four-wave mixing processes, by combining
the (linear) physics of TE-TM splitting with spin-dependent nonlinear
processes, i.e., exciton-exciton interaction and fermionic phase-space filling.
Our combined theoretical and experimental study elucidates the complex physics
of the four-wave mixing processes that govern polarization and orientation of
off-axis modes.",1512.01378v1
2016-02-03,Two-dimensional dispersion of magnetostatic volume spin waves,"The dipolar (magnetostatic) interaction dominates the behavior of spin waves
in magnetic films in the long-wavelength regime. In an in-plane magnetized
film, volume modes exist with a negative group velocity (backward volume
magnetostatic spin waves), in addition to the forward surface-localized mode
(Damon-Eshbach). Inside the film of finite thickness $L$, the volume modes have
a nontrivial spatial dependence, and their two-dimensional dispersion relations
$\omega(\mathbf{k})$ can be calculated only numerically. We present explicit
perturbative expressions for the profiles and frequencies of the volume modes,
taking into account an in-plane applied field and uniaxial anisotropy, for the
regimes $\lVert \mathbf{k}L \rVert \gg 1$ and $\lVert \mathbf{k}L \rVert \ll
1$, which together provide a good indication of the behavior of the modes for
arbitrary wavevector $\mathbf{k}$. Moreover, we derive a very accurate
semianalytical expression for the dispersion relation $\omega(\mathbf{k})$ of
the lowest-frequency mode that is straightforward to evaluate using standard
numerical routines. Our results are useful to quickly interpret and control the
excitation and propagation of spin waves in (opto-)magnetic experiments.",1602.01362v1
2016-04-26,Modulated spin helicity stabilized by incommensurate orbital density waves in a quadruple perovskite manganite,"Through a combination of neutron diffraction and Landau theory we describe
the spin ordering in the ground state of the quadruple perovskite manganite
CaMn7O12 - a magnetic multiferroic supporting an incommensurate orbital density
wave that onsets above the magnetic ordering temperature, TN1 = 90 K. The
multi-k magnetic structure in the ground state was found to be a
nearly-constant-moment helix with modulated spin helicity, which oscillates in
phase with the orbital occupancies on the Mn3+ sites via trilinear
magneto-orbital coupling. Our phenomenological model also shows that, above TN2
= 48 K, the primary magnetic order parameter is locked into the orbital wave by
an admixture of helical and collinear spin density wave structures.
Furthermore, our model naturally explains the lack of a sharp dielectric
anomaly at TN1 and the unusual temperature dependence of the electrical
polarisation.",1604.07747v1
2016-07-05,Non-classical correlations between a C-band telecom photon and a stored spin-wave,"Future ground-based quantum information networks will likely use single
photons transmitted through optical fibers to entangle individual network
nodes. To extend communication distances and overcome limitations due to photon
absorption in fibers the concept of quantum repeaters has been proposed. For
that purpose, it is required to achieve quantum correlations between the
material nodes and photons at telecom wavelengths which can be sent over long
distances in optical fibers. Here we demonstrate non-classical correlation
between a frequency converted telecom C-band photon and a spin-wave stored in
an atomic ensemble quantum memory. The photons emitted from the ensemble and
heralding the spin-waves are converted from 780 nm to 1552 nm by means of an
all-solid-state integrated waveguide non-linear device. We show ultra-low noise
operation of the device enabling a high signal to noise ratio of the converted
single photon, leading to a high spin-wave heralding efficiency. The presented
work is an enabling step towards the practical entanglement of remote quantum
memories and the entanglement of quantum systems operating at different
wavelengths.",1607.01350v1
2016-09-27,Sewing Greenberger-Horne-Zeilinger states with a quantum zipper,"A mechanism of a chiral spin wave rotation is introduced to systematically
generate mesoscopic Greenberger-Horne-Zeilinger states.",1609.08589v1
2017-08-21,Micromagnetic simulations of magnetoelastic spin wave excitation in scaled magnetic waveguides,"We study the excitation of spin waves in scaled magnetic waveguides using the
magnetoelastic effect. In uniformly magnetized systems, normal strains parallel
or perpendicular to the magnetization direction do not lead to spin wave
excitation since the magnetoelastic torque is zero. Using micromagnetic
simulations, we show that the nonuniformity of the magnetization in submicron
waveguides due to the effect of the demagnetizing field leads to the excitation
of spin waves for oscillating normal strains both parallel and perpendicular to
the magnetization. The excitation by biaxial normal in-plane strain was found
to be much more efficient than by uniaxial normal out-of-plane strain. For
narrow waveguides with widths of 200\,nm, the excitation efficiency of biaxial
normal in-plane strain was comparable to that of shear strain.",1708.06428v1
2018-03-26,Tunable Snell's law for spin waves in heterochiral magnetic films,"Thin ferromagnetic films with an interfacially induced DMI exhibit nontrivial
asymmetric dispersion relations that lead to unique and useful magnonic
properties. Here we derive an analytical expression for the magnon propagation
angle within the micromagnetic framework and show how the dispersion relation
can be approximated with a comprehensible geometrical interpretation in the
k-space of the propagation of spin waves. We further explore the refraction of
spin waves at DMI interfaces in heterochiral magnetic films, after deriving a
generalized Snell's law tunable by an in-plane magnetic field, that yields
analytical expressions for critical incident angles. The found asymmetric
Brewster angles at interfaces of regions with different DMI strengths,
adjustable by magnetic field, support the conclusion that heterochiral
ferromagnetic structures are an ideal platform for versatile spin-wave guides.",1803.09648v1
2014-06-23,Magnon-Driven Domain-Wall Motion with the Dzyaloshinskii-Moriya Interaction,"We study domain wall (DW) motion induced by spin waves (magnons) in the
presence of Dzyaloshinskii-Moriya interaction (DMI). The DMI exerts a torque on
the DW when spin waves pass through the DW, and this torque represents a linear
momentum exchange between the spin wave and the DW. Unlike angular momentum
exchange between the DW and spin waves, linear momentum exchange leads to a
rotation of the DW plane rather than a linear motion. In the presence of an
effective easy plane anisotropy, this DMI induced linear momentum transfer
mechanism is significantly more efficient than angular momentum transfer in
moving the DW.",1406.5997v2
2014-06-27,Observation of propagating edge spin waves modes,"Broadband magnetization response of equilateral triangular 1000 nm Permalloy
dots has been studied under an in-plane magnetic field, applied parallel
(buckle state) and perpendicular (Y state) to the triangles base. Micromagnetic
simulations identify edge spin waves (E-SWs) in the buckle state as SWs
propagating along the two adjacent edges. These quasi one-dimensional spin
waves emitted by the vertex magnetic charges gradually transform from
propagating to standing due to interference and are weakly affected by dipolar
interdot interaction and variation of the aspect ratio. Spin waves in the Y
state have a two dimensional character. These findings open perspectives for
implementation of the E-SWs in magnonic crystals and thin films.",1406.7186v1
2018-12-13,Spin-Orbital Density Wave and a Mott Insulator in a Two-Orbital Hubbard Model on a Honeycomb Lattice,"Inspired by recent discovery of correlated insulating states in twisted
bilayer graphene (TBG), we study a two-orbital Hubbard model on the honeycomb
lattice with two electrons per unit cell. Based on the real-space density
matrix renormalization group (DMRG) simulation, we identify a metal-insulator
transition around $U_c/t=2.5\sim3$. In the vicinity of $U_c$, we find strong
spin/orbital density wave fluctuations at commensurate wavevectors, accompanied
by weaker incommensurate charge density wave (CDW) fluctuations. The
spin/orbital density wave fluctuations are enhanced with increasing system
sizes, suggesting the possible emergence of long-range order in the two
dimensional limit. At larger $U$, our calculations indicate a possible
nonmagnetic Mott insulator phase without spin or orbital polarization. Our
findings offer new insights into correlated electron phenomena in twisted
bilayer graphene and other multi-orbital honeycomb materials.",1812.05661v3
2019-02-19,Spatial spin-wave modulator for quantum memory assisted adaptive measurements,"Utilization of the spatial degree of freedom vastly enhances informational
capacity of light at the cost of stringent requirements on the processing
devices. Multi-mode quantum memories constitute a viable candidate for quantum
and classical information processing; however, full utilization of the assets
of high-dimensionality requires a flexible processing technique. We employ a
spatially varying ac-Stark effect to perform arbitrary 1D phase modulation of a
coherent spin-wave state stored in a wavevector-multiplexed quantum memory. A
far-field and an interferometric near-field characterizations of the introduced
phase profiles are presented. Additionally, coherence between temporally
separated partial readouts of a single coherent spin-wave state is
demonstrated, offering possible applications in adaptive measurements via
conditional spin-wave modulation.",1902.07255v1
2019-06-19,Edge localization of spin waves in antidot multilayers with perpendicular magnetic anisotropy,"We study the spin-wave dynamics in nanoscale antidot lattices based on Co/Pd
multilayers with perpendicular magnetic anisotropy. Using time-resolved
magneto-optical Kerr effect measurements we demonstrate that the variation of
the antidot shape introduces significant change in the spin-wave spectra,
especially in the lower frequency range. By employing micromagnetic simulations
we show that additional peaks observed in the measured spectra are related to
narrow shell regions around the antidots, where the magnetic anisotropy is
reduced due to the Ga+ ion irradiation during the focused ion beam milling
process of the antidot fabrication. The results point at new possibilities for
exploitation of localized spin waves in out-of-plane magnetized thin films,
which are easily tunable and suitable for magnonics applications.",1906.08109v2
2019-06-21,Goos-Hänchen effect of spin waves at heterochiral interfaces,"We theoretically investigate the Goos-H\""{a}nchen (GH) effect of spin-wave
beams reflected from the interface between two ferromagnetic films with
different Dzyaloshinskii-Moriya interactions (DMIs). The formula of the GH
shift as functions of the incident angle and material parameters is derived
analytically. We show that the GH effect occurs only when spin waves are
totally reflected at the interface and vanishes otherwise. We further explore
the GH shift of spin waves by narrow DMI strips of different widths. It is
found that the induced shift is independent of the strip width down to $10$ nm,
offering a novel approach to measure the DMI strength of ultra-narrow magnetic
strips which is out the scope of current technology. Full micromagnetic
simulations compare well with our theoretical findings. Strong distortion of
edge magnetizations for narrower strips however generates a width dependence of
the GH shift. The results presented in this work are helpful for understanding
the GH effect in chiral magnets and for quantifying the DMI parameter in
magnetic strips of sub-$50$ nm scales.",1906.08999v2
2016-03-03,Cloaking the magnons,"We propose two approaches to cloak the spin waves (magnons) by investigating
magnetization dynamics. One approach is based on a spatially inhomogeneous
anisotropic magnetic moment tensor. The other mechanism is using a spatially
inhomogeneous anisotropic gyromagnetic factor tensor and an inhomogeneous
external magnetic field. For both approaches, the damping tensor is also
inhomogeneous and anisotropic. The magnetic characteristic functions of the
magnetic materials have been theoretically derived for both mechanisms. A
non-magnetic core, which prevents magnons from entering and consequently
distorts the spin wave propagation, can be cloaked by a structured magnetic
shell to redirect the spin wave around the core using the above design
mechanisms. We discuss the feasibility of the proposed mechanisms in an
ensemble of quantum dot molecules and magnetic semiconductors. The proposed
approaches shed light on transformation magnonics, and can be utilized for
future spin-wave lenses, concentrators, low back-scattering waveguides, and
ultimately quantum computing.",1603.01000v1
2016-12-15,Experimental prototype of a spin-wave majority gate,"Featuring low heat dissipation, devices based on spin-wave logic gates
promise to comply with increasing future requirements in information
processing. In this work, we present the experimental realization of a majority
gate based on the interference of spin waves in an Yttrium-Iron-Garnet-based
waveguiding structure. This logic device features a three-input combiner with
the logic information encoded in the phase of the spin waves. We show that the
phase of the output signal represents the majority of the phase of the input
signals. A switching time of about 10 ns in the prototype device provides
evidence for the ability of sub-nanosecond data processing in future
down-scaled devices.",1612.07708v1
2017-10-25,Collective spin waves in arrays of Permalloy nanowires with single-side periodically modulated width,"We have experimentally and numerically investigated the dispersion of
collective spin waves prop-agating through arrays of longitudinally magnetized
nanowires with periodically modulated width. Two nanowire arrays with
single-side modulation and different periodicity of modulation were studied and
compared to the nanowires with homogeneous width. The spin-wave dispersion,
meas-ured up to the third Brillouin zone of the reciprocal space, revealed the
presence of two dispersive modes for the width-modulated NWs, whose amplitude
of magnonic band depends on the modula-tion periodicity, and a set of
nondispersive modes at higher frequency. These findings are different from
those observed in homogeneous width NWs where only the lowest mode exhibits
sizeable dis-persion. The measured spin-wave dispersion has been satisfactorily
reproduced by means of dynam-ical matrix method. Results presented in this work
are important in view of the possible realization of frequency tunable magnonic
device.",1710.09163v1
2018-04-16,Quantum optics of spin waves through ac Stark modulation,"We bring the set of linear quantum operations, important for many fundamental
studies in photonic systems, to the material domain of collective excitations
known as spin waves. Using the ac Stark effect we realize quantum operations on
single excitations and demonstrate a spin-wave analogue of Hong-Ou-Mandel
effect, realized via a beamsplitter implemented in the spin wave domain. Our
scheme equips atomic-ensemble-based quantum repeaters with quantum information
processing capability and can be readily brought to other physical systems,
such as doped crystals or room-temperature atomic ensembles.",1804.05854v2
2019-03-03,Spin wave damping in periodic and quasiperiodic magnonic structures,"We investigated the lifetime of spin wave eigenmodes in periodic and
quasiperiodic sequences of Py and Co wires. Those materials differ
significantly in damping coefficients, therefore, the spatial distribution of
the mode amplitude within the structure is important for the lifetime of
collective spin wave excitations. Modes of the lower frequencies prefer to
concentrate in Py wires, because of the lower FMR frequency for this material.
This inhomogeneous distribution of amplitude of modes (with lower amplitude in
material of higher damping and with higher amplitude in material of lower
damping) is preferable for extending the lifetime of the collective excitations
beyond the volume average of lifetimes for solid materials. We established the
relation between the profile of the mode and its lifetime for periodic and
quasiperiodic structures. We performed also the comparative studies in order to
find the differences resulting from complexity of the structure and enhancement
of localization in quasiperiodic system on the lifetime of spin waves.",1903.00856v1
2019-03-11,Spin waves in thin films and magnonic crystals with Dzyaloshinskii-Moriya interactions,"The influence of the Dzyaloshinskii-Moriya interaction in ultra-thin
ferromagnetic films and chiral magnonic crystals on the behavior of spin waves
is reviewed. During the last decade, it has been shown, both theoretically and
experimentally, that this anisotropic exchange interaction produces
non-reciprocal features on the spin-wave spectrum of a magnetic system, a
phenomenon that occurs both for bulk and interfacial Dzyaloshinskii-Moriya
coupling. More recently, the concept of a chiral magnonic crystal has been
introduced, where the interfacial Dzyaloshinskii-Moriya interaction is
periodic. The effect of this periodicity include additional features such as
flat bands, indirect gaps, and an unusual spin-wave evolution.",1903.04288v2
2019-05-08,Nanoscale spin-wave wake-up receiver,"We present the concept of a passive spin-wave device which is able to
distinguish different radio-frequency pulse trains and validate its
functionality using micromagnetic simulations. The information is coded in the
phase of the individual pulses which are transformed into spin-wave packets.
The device splits every incoming packet into two arms, one of which is coupled
to a magnonic ring which introduces a well-defined time delay and phase shift.
Since the time delay is matched to the pulse repetition rate, adjacent packets
interfere in a combiner which makes it possible to distinguish simple pulse
train patterns by the read-out of the time-integrated spin-wave intensity in
the output. Due to its passive construction, this device may serve as an
energy-efficient wake-up receiver used to activate the main receiver circuit in
power critical IoT applications.",1905.03006v1
2019-05-13,Unmodelled Clustering Methods for Gravitational Wave Populations of Compact Binary Mergers,"The mass and spin distributions of compact binary gravitational-wave sources
are currently uncertain due to complicated astrophysics involved in their
formation. Multiple sub-populations of compact binaries representing different
evolutionary scenarios may be present among sources detected by Advanced LIGO
and Advanced Virgo. In addition to hierarchical modelling, unmodelled methods
can aid in determining the number of sub-populations and their properties. In
this paper, we apply Gaussian mixture model clustering to 1000 simulated
gravitational-wave compact binary sources from a mixture of five
sub-populations. Using both mass and spin as input parameters, we determine how
many binary detections are needed to accurately determine the number of
sub-populations and their mass and spin distributions. In the most difficult
case that we consider, where two sub-populations have identical mass
distributions but differ in their spin, which is poorly constrained by
gravitational-wave detections, we find that ~ 400 detections are needed before
we can identify the correct number of sub-populations.",1905.04825v2
2020-09-17,Spin-wave focusing induced skyrmion generation,"We propose a new method to generate magnetic skyrmions through spin-wave
focusing in chiral ferromagnets.A lens is constructed to focus spin waves by a
curved interface between two ferromagnetic thin films with different
perpendicular magnetic anisotropies. Based on the principle of identical
magnonic path length, we derive the lens contour that can be either elliptical
or hyperbolical depending on the magnon refractive index. Micromagnetic
simulations are performed to verify the theoretical design. It is found that
under proper condition magnetic skyrmions emerge near the focus point of the
lens where the spin-wave intensity has been significantly enhanced. A close
investigation shows that a magnetic droplet first forms and then converts to
the skyrmion accompanying with a change of topological charge. Phase diagram
about the amplitude and duration-time of the exciting field for skyrmion
generation is obtained. Our findings would be helpful for designing novel
spintronic devices combining the advantages of skyrmionics and magnonics.",2009.08091v1
2020-11-02,Spin wave propagation in corrugated waveguides,"Curvature-induced effects allow us to tailor the static and dynamic response
of a magnetic system with a high degree of freedom. We study corrugated
magnonic waveguides deposited on a sinusoidally modulated substrate prepared by
focused electron beam deposition. The surface curvature in films with
thicknesses comparable to the amplitude of modulation locally modifies the
contributions of dipolar and exchange energies and results in an effective
anisotropy term which can be tuned on-demand based on the exact geometry. We
show, by Brillouin light scattering microscopy, that without the presence of an
external magnetic field, spin waves propagate over a distance 10$\times$larger
in the corrugated waveguide than in the planar waveguide. Further, we analyze
the influence of the modulation amplitude on spin-wave propagation and conclude
that for moderate modulation amplitudes, the spin-wave decay length is not
affected. For larger amplitudes, the decay length decreases linearly with
increasing modulation.",2011.01274v1
2020-11-23,Asymmetric spin wave dispersion due to a saturation magnetization gradient,"We demonstrate using micromagnetic simulations and a theoretical model that a
gradient in the saturation magnetization ($M_s$) of a perpendicularly
magnetized ferromagnetic film induces a non-reciprocal spin wave propagation
and, consequently an asymmetric dispersion relation. The $M_s$ gradient adds a
linear potential to the spin wave equation of motion consistent with the
presence of a force. We consider a transformation from an inertial reference
frame in which the $M_s$ is constant to an accelerated reference frame where
the resulting inertial force corresponds to the force from the $M_s$ gradient.
As in the Doppler effect, the frequency shift leads to an asymmetric dispersion
relation. Additionally, we show that under certain circumstances,
unidirectional propagation of spin waves can be achieved which is essential for
the design of magnonic circuits. Our results become more relevant in light of
recent experimental works in which a suitable thermal landscape is used to
dynamically modulate the saturation magnetization.",2011.11148v2
2021-08-02,Spin Wave Computing using pre-recorded magnetization patterns,"We propose a novel type of a spin wave computing device, based on a bilayer
structure which includes a bias layer, made from a hard magnetic material and a
propagation layer, made from a magnetic material with low damping, for example,
Yttrium Garnet (YiG) or Permalloy. The bias layer maintains a stable
pre-recorded magnetization pattern, generating a bias field with a desired
spatial dependence, which in turn sets the equilibrium magnetization inside the
propagation layer. When an external source applies an RF field or spinwave to
the propagation layer, excited spin waves scatter on the magnetization's
inhomogenuities, resulting in a complex interference behavior. One thus has the
ability to adjust spin wave propagation properties simply by altering the
magnetization in the bias layer. We demonstrate that the phenomenon can be
utilized to perform a variety of computational operations, including Fourier
Transform, Vector-Matrix multiplication and Grover search algorithm, with the
operational parameters exceeding conventional designs by orders of magnitude.",2108.00909v1
2016-11-29,Superdirectional Beam of Surface Spin Wave,"The visualized diffraction patterns of surface spin wave excited by
arbitrarily oriented linear transducer are investigated experimentally in the
plane of tangentially magnetized ferrite film for the case where the transducer
length D is much larger than the wavelength L. It is shown experimentally and
theoretically that the angular width of diffracted surface spin wave beam in
anisotropic ferrite film can take values greater or less than L/D and can also
be zero. For the last case superdirectional (nonexpanding) beam of the surface
spin wave is observed experimentally: the smearing of the beam energy along the
film plane is absent and the length of the beam trajectory is maximal (~50 mm).",1611.09595v2
2017-03-20,Spin-wave excitations in the SDW state of doped iron pnictides,"We investigate the spin-wave excitations in the spin-density wave state of
doped iron pnictides within a five-orbital model. We find that the excitations
along ($\pi, 0$)$\rightarrow$($\pi, \pi$) are very sensitive to the doping
whereas they do not exhibit a similar sensitivity along ($0, 0$) $\rightarrow$
($\pi, 0$). Secondly, anisotropy in the excitations around ($\pi, 0$) with an
elliptical shape grows on moving towards the hole-doped region for low energy,
whereas it decreases for the high-energy excitations on the contrary. Thirdly,
spin-wave spectral weight shifts towards the low-energy region on moving away
from zero doping. We find these features to be in qualitative agreement with
the inelastic neutron-scattering measurements for the doped pnictides.",1703.06601v1
2019-01-18,Magnon-Fluxon interaction in a ferromagnet/superconductor heterostructure,"Ferromagnetism and superconductivity are most fundamental phenomena in
condensed matter physics. Entailing opposite spin orders, they share an
important conceptual similarity: Disturbances in magnetic ordering in magnetic
materials can propagate in the form of spin waves (magnons) while magnetic
fields penetrate superconductors as a lattice of magnetic flux quanta
(fluxons). Despite a rich choice of wave and quantum phenomena predicted,
magnon-fluxon coupling has not been observed experimentally so far. Here, we
clearly evidence the interaction of spin waves with a flux lattice in
ferromagnet/superconductor Py/Nb bilayers. We demonstrate that, in this system,
the magnon frequency spectrum exhibits a Bloch-like band structure which can be
tuned by the biasing magnetic field. Furthermore, we observe Doppler shifts in
the frequency spectra of spin waves scattered on a flux lattice moving under
the action of a transport current in the superconductor.",1901.06156v1
2019-09-16,Skyrmions and spin waves in frustrated ferromagnets at low applied magnetic field,"A continuum model of frustrated ferromagnets is analyzed in detail in the
regime of low applied magnetic field, $H_0<1/4$, where the ground state is a
spatially varying conical spiral. By changing variables to a corotating spin
field, the model is reformulated as a gauged sigma model in a fixed background
gauge, allowing the construction of stable isolated Skyrmions, and stable
multi-Skyrmion clusters, which approach the conical ground state at spatial
infinity. Owing to the spatial anisotropy induced by the ground state, these
Skyrmions exhibit only discrete symmetries, and are of neither N\'eel nor Bloch
type. These Skyrmions are continuously connected to the more familar solutions
in the high field regime ($H_0>1/4$), acquiring axial symmetry in the limit
$H_0\rightarrow 1/4$. The propagation of small amplitude spin waves through the
conical ground state is also analyzed and is found to depend strongly on both
$H_0$ and propagation direction relative to the ground state. In contrast to
spin waves in the high field regime ($H_0>1/4$) there is no spectral gap: waves
may propagate with any angular frequency.",1909.07970v2
2019-09-21,Deterministic generation and partial retrieval of a spin-wave excitation in an atomic ensemble,"In this paper, we report a generation of a spin-wave excitation (SWE) with a
near-unity () probability in a given time (~730). Such deterministic generation
relies on a feedback scheme with a millisecond quantum memory. The millisecond
memory is achieved by maximizing the wavelength of the spin wave and storing
the SWE as the magnetic-field-insensitive transition. We then demonstrate
partial retrievals of the spin wave by applying a first read pulse whose area
is smaller than the value of . The remained SWE is fully retrieved by a second
pulse. Anti-correlation function between the detections in the first and second
readouts has been measured, which shows that the partial-retrieval operation on
the SWE is in the quantum regime. The presented experiment represents an
important step towards the realization of the improved DLCZ quantum repeater
protocol proposed in Phys. Rev. A 77, 062301 (2008).",1909.09766v1
2020-01-18,Off-axial focusing of spin-wave lens in the presence of Dzyaloshinskii-Moriya interaction,"We theoretically study the effect of Dzyaloshinskii-Moriya interaction (DMI)
on the focusing of a spin-wave lens that is constructed by a circular interface
between two magnetic films. We analytically derive the generalized Snell's law
in the curved geometry and the position of the focal point which exhibits a
peculiar off-axial focusing behavior. We uncover a strong dependence of the
focal point on both the material parameters and the frequency of incident spin
waves. Full micromagnetic simulations compare well with theoretical
predictions. Our findings would be helpful to manipulate spin waves in chiral
magnets and to design functional magnonic devices.",2001.06604v1
2020-02-11,Sub-micrometer near-field focusing of spin waves in ultrathin YIG films,"We experimentally demonstrate tight focusing of a spin wave beam excited in
extended nanometer-thick films of Yttrium Iron Garnet by a simple microscopic
antenna functioning as a single-slit near-field lens. We show that the focal
distance and the minimum transverse width of the focal spot can be controlled
in a broad range by varying the frequency/wavelength of spin waves and the
antenna geometry. The experimental data are in good agreement with the results
of numerical simulations. Our findings provide a simple solution for
implementation of magnonic nano-devices requiring local concentration of the
spin-wave energy.",2002.04284v1
2021-06-17,Anomalous spin waves in CsFeCl$_{3}$ and RbFeCl$_{3}$,"We investigate magnetic excitations in the $S=1$ easy-plan-type triangular
antiferromagnets CsFeCl$_{3}$ and RbFeCl$_{3}$ through a combination of
inelastic neutron scattering measurements and spin-wave theory calculations
based on an established exchange-coupling Hamiltonian. We show that in either
material the model falls short of providing an adequate description of the
measured intensities and for RbFeCl$_{3}$ even fails to reproduce the measured
dispersion relation. The most striking discrepancy is a very anisotropic
azimuthal intensity distribution in the acoustic spin-wave branches in the
long-wavelength limit, which is incompatible with spin-wave theory on a
fundamental level. The observed anomalies are attributed to long-range dipolar
interactions.",2106.09447v2
2021-09-22,Theory of the dipole-exchange spin wave spectrum in ferromagnetic films with in-plane magnetization revisited,"We present a refinement of the widely accepted spin-wave spectrum that
Kalinikos and Slavin computed for magnetic films with an in-plane magnetization
(1986). The spin wave spectrum that follows from the diagonal approximation in
this theory becomes inaccurate for relatively thick films, as has already been
noted by Kreisel et al. (2009). Rather than solving an integrodifferential
equation which follows from the magnetostatic Green's function, as done by
Kalinikos and Slavin, we impose the exchange and magnetostatic boundary
conditions on bulk spin-wave solutions. This boundary problem has an accurate
analytical solution which is quantitatively different from the commonly used
diagonal theory for magnetic films.",2109.10597v2
2021-09-30,Spin-Wave Quantum Computing with Atoms in a Single-Mode Cavity,"We present a method for network-capable quantum computing that relies on
holographic spin-wave excitations stored collectively in ensembles of qubits.
We construct an orthogonal basis of spin waves in a one-dimensional array and
show that high-fidelity universal linear controllability can be achieved using
only phase shifts, applied in both momentum and position space. Neither
single-site addressability nor high single-qubit cooperativity is required, and
the spin waves can be read out with high efficiency into a single cavity mode
for quantum computing and networking applications.",2109.15252v1
2021-12-21,Nonreciprocal spin-wave dynamics in Pt/Co/W/Co/Pt multilayers,"We present a detailed study of the spin-wave dynamics in single Pt/Co/W and
double Pt/Co/W/Co/Pt ferromagnetic layer systems. The dispersion of spin waves
was measured by wavevector-resolved Brillouin light scattering spectroscopy
while the in-plane and out-of-plane magnetization curves were measured by
alternating gradient field magnetometry. The interfacial Dzyaloshinskii-Moriya
interaction induced nonreciprocal dispersion relation was demonstrated for both
single and double ferromagnetic layers and explicated by numerical simulations
and theoretical formulas. The results indicate the crucial role of the order of
layers deposition on the magnetic parameters. A significant difference between
the perpendicular magnetic anisotropy constant in double ferromagnetic layer
systems conduces to the decline of the interlayer interactions and different
dispersion relations for the spin-wave modes. Our study provides a significant
contribution to the realization of the multifunctional nonreciprocal magnonic
devices based on ultrathin ferromagnetic/heavy-metal layer systems.",2112.11206v1
2022-01-11,All-sky analysis of astrochronometric signals induced by gravitational waves,"We introduce a unified formalism to describe both timing and astrometric
perturbations induced on astrophysical point sources by gravitational waves
using a complex spin field on the sphere. This allows the use of spin-weighted
spherical harmonics to analyse ""astrochronometric"" observables. This approach
simplifies the interpretation and simulation of anisotropies induced in the
observables by gravitational waves. It also allows a simplified derivation of
angular cross-spectra of the observables and their relationship with
generalised Hellings-Downs correlation functions. The spin-weighted formalism
also allows an explicit connection between correlation components and the spin
of gravitational wave polarisations and any presence of chirality. We also
calculate expected signal-to-noise ratios for observables to compare the
utility of timing and deflection observables.",2201.03903v1
2022-04-11,"On the ""old"" and ""new"" relativistic wave equations for the particle having spin s=3/2","Relativistic wave equation of motion without redundant components for the
particle having spin 3/2 has been considered. In order to show the newness a
comparison with the known equations for the spin s=3/2 field is given.
Therefore, the brief review of the relativistic wave equations for the particle
with spin s=3/2 is given. In our equation the wave function for the
particle-antiparticle doublet has only 8 components. The consideration is
carried out both at the level of relativistic quantum mechanics and at the
level of local field theory. The extended Foldy--Wouthuysen transformation,
which gives the operator link between these two levels is suggested.",2204.05167v2
2022-05-05,Spin-wave localization on phasonic defects in one-dimensional magnonic quasicrystal,"We report on the evolution of the spin-wave spectrum under structural
disorder introduced intentionally into one-dimensional magnonic quasicrystal.
We study theoretically a system composed of ferromagnetic strips arranged in a
Fibonacci sequence. We considered several stages of disorder in the form of
phasonic defects, where different rearrangements of strips are introduced. By
transition from the quasiperiodic order towards disorder, we show a gradual
degradation of spin-waves fractal spectra and closing of the frequency gaps. In
particular, the phasonic defects lead to the disappearance of the van Hove
singularities at the frequency gap edges by moving modes into the frequency
gaps and appearing new modes inside the frequency gaps. These modes disperse
and eventually can close the gap, with increasing disorder levels. The work
reveals how the the presence of disorder modifies the intrinsic spin wave
localization existing in undefected magnonic quasicrystals. The paper
contributes to the knowledge of magnonic Fibonacci quasicrystals and opens the
way to study of the phasonic defects in two-dimensional magnonic quasicrystals.",2205.02702v2
2022-07-07,Experimental Demonstration of High-Performance Physical Reservoir Computing with Nonlinear Interfered Spin Wave Multi-Detection,"Physical reservoir computing, which is a promising method for the
implementation of highly efficient artificial intelligence devices, requires a
physical system with nonlinearity, fading memory, and the ability to map in
high dimensions. Although it is expected that spin wave interference can
perform as highly efficient reservoir computing in some micromagnetic
simulations, there has been no experimental verification to date. Herein, we
demonstrate reservoir computing that utilizes multidetected nonlinear spin wave
interference in an yttrium iron garnet single crystal. The subject computing
system achieved excellent performance when used for hand-written digit
recognition, second-order nonlinear dynamical tasks, and nonlinear
autoregressive moving average (NARMA). It is of particular note that normalized
mean square errors (NMSEs) for NARMA2 and second-order nonlinear dynamical
tasks were 1.81x10-2 and 8.37x10-5, respectively, which are the lowest figures
for any experimental physical reservoir so far reported. Said high performance
was achieved with higher nonlinearity and the large memory capacity of
interfered spin wave multi-detection.",2207.03216v1
2022-08-24,Stimulated amplification of propagating spin waves,"Spin-wave amplification techniques are key to the realization of magnon-based
computing concepts. We introduce a novel mechanism to amplify spin waves in
magnonic nanostructures. Using the technique of rapid cooling, we create a
non-equilibrium state in excess of high-energy magnons and demonstrate the
stimulated amplification of an externally seeded, propagating spin wave. Using
an extended kinetic model, we qualitatively show that the amplification is
mediated by an effective energy flux of high energy magnons into the low energy
propagating mode, driven by a non-equilibrium magnon distribution.",2208.11455v2
2022-11-01,Nonlocal optical conductivity of Fermi surface nesting materials,"We investigate the nonlocal optical conductivity of Fermi surface nesting
materials which support charge density waves or spin density waves. The
nonlocal optical conductivity contains information of correlations in electron
fluids which could not be accessed by standard optical probes. Half metal
emerges from doping a charge density wave and similarly spin-valley half metal
emerges from doping a spin density wave. Based on the parabolic band
approximation, we find the Drude peak is shifted to higher frequency and splits
into two peaks in the nonlocal optical conductivity. We attribute this to the
two Fermi velocities in the half-metal or spin-valley half metal states.",2211.00244v1
2022-12-13,Spin wave spectra of single crystal CoPS$_3$,"The spin waves in single crystals of the layered van der Waals
antiferromagnet CoPS$_3$ have been measured using inelastic neutron scattering.
The data show four distinct spin wave branches with large ($\gtrsim 14$ meV)
energy gaps at the Brillouin zone center indicating significant anisotropy. The
data were modelled using linear spin wave theory derived from a Heisenberg
Hamiltonian. Exchange interactions up to the third nearest-neighbour in the
layered planes were required to fit the data with ferromagnetic $J_1 = -1.37$
meV between first neighbours, antiferromagnetic $J_3 = 3.0$ meV between third
neighbours, and a very small $J_2 = 0.09$ meV between second neighbours. A
biaxial single-ion anisotropy was required, with a collinear term $D^x = -0.77$
meV for the axis parallel to the aligned moment direction and a coplanar term
$D^z=6.07$ meV for an axis approximately normal to the layered crystal planes.",2212.06479v1
2023-02-14,"Singlet, Triplet and Pair Density Wave Superconductivity in the Doped Triangular-Lattice Moiré System","Recent experimental progress has established the twisted bilayer transition
metal dichalcogenide (TMD) as a highly tunable platform for studying many-body
physics. Particularly, the homobilayer TMDs under displacement field are
believed to be described by a generalized triangular-lattice Hubbard model with
a spin-dependent hopping phase $\theta$. To explore the effects of $\theta$ on
the system, we perform density matrix renormalization group calculations for
the relevant triangular lattice t-J model. By changing $\theta$ at small hole
doping, we obtain a region of quasi-long-range superconducting order coexisting
with charge and spin density wave within $0<\theta<\pi/3$. The
superconductivity is composed of a dominant spin singlet $d$-wave and a
subdominant triplet $p$-wave pairing. Intriguingly, the $S_z=\pm 1$ triplet
pairing components feature pair density waves. In addition, we find a region of
triplet superconductivity coexisting with charge density wave and
ferromagnetism within $\pi/3<\theta<2\pi/3$, which is related to the former
phase at smaller $\theta$ by a combined operation of spin-flip and gauge
transformation. Our findings provide insights and directions for experimental
search for exotic superconductivity in twisted TMD systems.",2302.06765v3
2023-04-17,Geometric phase and a nonreciprocal spin wave circular polarizer,"We show that spin wave acquires a polarization-dependent geometric phase
along a cyclic trajectory of non-coplanar magnetizations in antiferromagnets.
Specifically, we demonstrate that a cyclic set of 90 degree antiferromagnetic
domain walls simultaneously introduce geometric and dynamic phases to spin
wave, and thus leads to asymmetric magnitude of overall phase for
left-/right-circular components. Based on the polarization-dependent phase, we
propose theoretically and confirm by micromagnetic simulations that, a
Mach-Zehner interferometer with cyclic 90 degree domain walls in one arm and
homogenous domain in the other arm, naturally acts as a spin wave circular
polarizer. Moreover, the circular polarizer has intrinsic nonreciprocity, which
filters opposite polarization in opposite propagation direction.",2304.08071v1
2023-07-14,Gravitational partial-wave absorption from scattering amplitudes,"We study gravitational absorption effects using effective on-shell scattering
amplitudes. We develop an in-in probability-based framework involving plane-
and partial-wave coherent states for the incoming wave to describe the
interaction of the wave with a black hole or another compact object. We connect
this framework to a simplified single-quantum analysis. The basic ingredients
are mass-changing three-point amplitudes, which model the leading absorption
effects and a spectral-density function of the black hole. As an application,
we consider a non-spinning black hole that may start spinning as a consequence
of the dynamics. The corresponding amplitudes are found to correspond to
covariant spin-weighted spherical harmonics, the properties of which we
formulate and make use of. We perform a matching calculation to
general-relativity results at the cross-section level and derive the effective
absorptive three-point couplings. They are found to behave as ${\cal
O}(G_\text{Newton}^{s+1})$, where $s$ is the spin of the outgoing massive
state.",2307.07504v3
2023-12-28,Quantum Weyl-Heisenberg antiferromagnet,"Beginning from the conventional square-lattice nearest-neighbor
antiferromagnetic Heisenberg model, we allow the $J_x$ and $J_y$ couplings to
be anisotropic, with their values depending on the bond orientation. The
emergence of anisotropic, bond-dependent, couplings should be expected to occur
naturally in most antiferromagnetic compounds which undergo structural
transitions that reduce the point-group symmetry at lower temperature. Using
the spin-wave approximation, we study the model in several parameter regimes by
diagonalizing the reduced Hamiltonian exactly, and computing the edge spectrum
and Berry connection vector, which show clear evidence of localized topological
charges. We discover phases that exhibit Weyl-type spin-wave dispersion,
characterized by pairs of degenerate points and edge states, as well as phases
supporting lines of degeneracy. We also identify a parameter regime in which
there is an exotic state hosting gapless linear spin-wave dispersions with
different longitudinal and transverse spin-wave velocities.
  Author email info: prosenberg15@gmail.com and manousakis@gmail.com",2312.17028v1
2023-12-31,Multiplexed entanglement swapping with atomic-ensemble-based quantum memories in the single excitation regime,"Entanglement swapping (ES) between memory repeater links is critical for
establishing quantum networks via quantum repeaters. So far, ES with
atomic-ensemble-based memories has not been achieved. Here, we experimentally
demonstrated ES between two entangled pairs of spin-wave memories via
Duan-Lukin-Cirac-Zoller scheme. With a cloud of cold atoms inserted in a
cavity, we produce non-classically-correlated spin-wave-photon pairs in 12
spatial modes and then prepare two entangled pairs of spin-wave memories via a
multiplexed scheme. Via single-photon Bell measurement on retrieved fields from
two memories, we project the two remaining memories never entangled previously
into an entangled state with the measured concurrence of C = 0.0124(0.003). The
successful probability of ES in our scheme is increased by three times,
compared with that in non-multiplexed scheme. Our presented work shows that the
generation of entanglement (C>0) between the remaining memory ensembles
requires the average cross-correlation function of the spin-wave-photon pairs
to be >30 .",2401.00519v1
2024-03-23,Spatial Control of Hybridization-Induced Spin-Wave Transmission Stop Band,"Spin-wave (SW) propagation close to the hybridization-induced transmission
stop band is investigated within a trapezoid-shaped 200\,nm thick yttrium iron
garnet (YIG) film using time-resolved magneto-optic Kerr effect (TR-MOKE)
microscopy and broadband spin wave spectroscopy, supported by micromagnetic
simulations. The gradual reduction of the effective field within the structure
leads to local variations of the SW dispersion relation and results in a SW
hybridization at a fixed position in the trapezoid where the propagation
vanishes since the SW group velocity approaches zero. By tuning external field
or frequency, spatial control of the spatial stop band position and spin-wave
propagation is demonstrated and utilized to gain transmission control over
several microstrip lines.",2403.15840v1
2008-09-16,Non-Statistical Effects in Neutron Capture,"There have been many reports of non-statistical effects in neutron-capture
measurements. However, reports of deviations of reduced-neutron-width
distributions from the expected Porter-Thomas (PT) shape largely have been
ignored. Most of these deviations have been reported for odd-A nuclides.
Because reliable spin (J) assignments have been absent for most resonances for
such nuclides, it is possible that reported deviations from PT might be due to
incorrect J assignments. We recently developed a new method for measuring spins
of neutron resonances by using the DANCE detector at LANSCE. Measurements made
with a 147Sm sample allowed us to determine spins of almost all known
resonances below 1 keV. Furthermore, analysis of these data revealed that the
reduced-neutron-width distribution was in good agreement with PT for resonances
below 350 eV, but in disagreement with PT for resonances between 350 and 700
eV. Our previous (n,alpha) measurements had revealed that the alpha strength
function also changes abruptly at this energy. There currently is no known
explanation for these two non-statistical effects. Recently, we have developed
another new method for determining the spins of neutron resonances. To
implement this technique required a small change (to record pulse-height
information for coincidence events) to a much simpler apparatus: A pair of C6D6
gamma-ray detectors which we have employed for many years to measure
neutron-capture cross sections at ORELA. Measurements with a 95Mo sample
revealed that not only does the method work very well for determining spins,
but it also makes possible parity assignments. Taken together, these new
techniques at LANSCE and ORELA could be very useful for further elucidation of
non-statistical effects.",0809.2762v1
2002-10-15,Nonthermal Emissions from Particles Accelerated by Turbulence in Clusters of Galaxies,"We consider nonthermal emission from clusters of galaxies produced by
particle acceleration by resonant scattering of Alfv\'{e}n waves driven by
fluid turbulence through the Lighthill mechanism in the intracluster medium. We
assume that the turbulence is driven by cluster mergers. We find that the
resonant Alfv\'{e}n waves can accelerate electrons up to
  \gamma ~10^5 through resonant scattering. We also find that the turbulent
resonant acceleration can give enough energy to electrons to produce the
observed diffuse radio relic emission from clusters if the clusters have a pool
of electrons with \gamma ~10^3.
  This mechanism can also explain the observed hard X-ray emission from
clusters if the magnetic field in a cluster is small enough (~<
  \mu G) or the fluid turbulence spectrum is flatter than the Kolmogorov law.
The fluid turbulence could be observed with Astro-E2 in the regions where
diffuse radio emission is observed. Although non-gravitational heating before
cluster formation (preheating) steepens a relation between radio luminosity and
X-ray temperature, our predicted relation is still flatter than the observed
one.",0210320v1
1999-04-01,Dimer-Type Correlations and Band Crossings in Fibonacci Lattices,"Fibonacci system with both diagonal and off-diagonal disorder is mapped to a
model with dimer type 'defects'. The model exhibit resonance transition
corresponding to zero reflectance condition resulting in extended states in the
system. These Bloch-type states reside on the line of inversion symetry of the
energy spectrum and include states at the band crossings. The resonant states
at the band crossings are related to the harmonics of the sine wave and have
transmission coefficient equal to unity in quasiperiodic limit. This is in
contrast to other resonant states where the transmission coeffiecient
oscillates. An exact renormalization scheme confirms the fact that all resonant
states are Bloch type waves as they are described by trivial attractors of the
renormalization flow.",9904022v1
2002-11-15,Fano resonances with discrete breathers,"A theoretical study of linear wave scattering by time-periodic spatially
localized excitations (discrete breathers (DB)) is presented. We obtain that
the wave propagation is strongly influenced by a local coupling between an open
and closed channels generated by the DB. A peculiar effect of total reflection
occurs due to a Fano resonance when a localized state originating from closed
channels resonates with the open channel. For the discrete nonlinear
Schroedinger chain we provide with an analytical result for the frequency
dependence of the transmission coefficient, including the possibility of
resonant reflection. We extend the analysis to chains of weakly coupled
anharmonic oscillators and discuss the relevance of the effect for electronic
transport spectroscopy of mesoscopic systems.",0211313v1
2003-11-24,Soft x-ray resonant diffraction study of magnetic and orbital correlations in a manganite near half-doping,"We have utilized the resonant x-ray diffraction technique at the Mn L-edge in
order to directly compare magnetic and orbital correlations in the Mn
sub-lattice of Pr0.6Ca0.4MnO3. The resonant line shape is measured below T_OO ~
240 K at the orbital ordering wave vector (0,1/2,0), and below T_N ~ 175 K at
the antiferromagnetic wave vector (1/2,0,0). Comparing the width of the
super-lattice peaks at the two wavevectors, we find that the correlation length
of the magnetism exceeds that of the orbital order by nearly a factor of two.
Furthermore, we observe a large (~ 3 eV) shift in spectral weight between the
magnetic and orbital line shapes, which cannot be explained within the classic
Goodenough picture of a charge-ordered ground state. To explain the large
shift, we calculate the resonant line shapes for orbital and magnetic
diffraction based on a relaxed charge-ordered model.",0311553v1
2004-08-31,Handedness of magnetic-dipolar modes in ferrite disks,"For magnetic-dipolar modes in a ferrite, components of the magnetic flux
density in a helical coordinate system are dependent on both an orientation of
a gyration vector and a sign of a pitch. It gives four types of helical
harmonics for magnetostatic-potential wave functions in a ferrite disk. Because
of the reflection symmetry breaking, coupling between certain types of helical
harmonics takes place in the reflection points. The reflection feature leads to
exhibition of two types of resonances: the ""right"" and ""left"" resonances. These
resonances become coupled for a ferrite disk placed in a homogeneous tangential
RF magnetic field. One also observes such resonance coupling for a ferrite disk
with a symmetrically oriented linear surface electrode, when this ferrite
particle is placed in a homogeneous tangential RF electric field. In a
cylindrical coordinate system handedness of magnetic-dipolar modes in a ferrite
disk is described by spinor wave functions.",0408682v2
2005-02-24,3-mode detection for widening the bandwidth of resonant gravitational wave detectors,"We have implemented a novel scheme of signal readout for resonant
gravitational wave detectors. For the first time, a capacitive resonant
transducer has been matched to the signal amplifier by means of a tuned high Q
electrical resonator. The resulting 3-mode detection scheme widens
significantly the bandwidth of the detector. We present here the results
achieved by this signal readout equipped with a two-stage SQUID amplifier. Once
installed on the AURIGA detector, the one-sided spectral sensitivity obtained
with the detector operated at 4.5 K is better than 10^-20 Hz^-1/2 over 110 Hz
and in good agreement with the expectations.",0502101v1
2004-03-03,Analytic continuation of single-particle resonance energy and wave function in relativistic mean field theory,"Single-particle resonant states in spherical nuclei are studied by an
analytic continuation in the coupling constant (ACCC) method within the
framework of the self-consistent relativistic mean field (RMF) theory. Taking
the neutron resonant state $\nu 1g_{9/2}$ in $^{60}$Ca as an example, we
examine the analyticity of the eigenvalue and eigenfunction for the Dirac
equation with respect to the coupling constant by means of a $\pade$
approximant of the second kind. The RMF-ACCC approach is then applied to
$^{122}$Zr and, for the first time, this approach is employed to investigate
both the energies, widths and wave functions for $l\ne 0$ resonant states close
to the continuum threshold. Predictions are also compared with corresponding
results obtained from the scattering phase shift method.",0403013v1
2004-06-17,Presence of Extra P11 Resonances in Zagreb Analysis Since 1995,"The partial wave T-matrices for the pi N, eta N and pi2 N channels have been
obtained within the framework of the coupled channel model using the pi N
elastic and pi N --> eta N data base as input. It has been shown that for the
P11 partial wave an equally good representation of the experimental data
(namely the T(pi N,pi N) and T(pi N,eta N) T-matrices) can be obtained using
either three, or four poles for the Green function propagator. However, the
three Green function pole solution is not acceptable due to the structure of
the extracted resonances. The two out of four P11 resonances, those lying in
the energy range 1700 MeV < MR < 1800 MeV, are poorly determined, but they seem
to be strongly inelastic. The inclusion of other inelastic channels is needed
to determine masses and widths of missing resonances with greater precision.",0406058v1
2005-12-01,Anatomy of three-body decay III. Energy distributions,"We address the problem of calculating momentum distributions of particles
emerging from the three-body decay of a many-body resonance. We show that these
distributions are determined by the asymptotics of the coordinate-space
complex-energy wave-function of the resonance. We use the hyperspherical
adiabatic expansion method where all lengths are proportional to the
hyperradius. The structures of the resonances are related to different decay
mechanisms. For direct decay all inter-particle distances increase proportional
to the hyperradius at intermediate and large distances. Sequential three-body
decay proceeds via spatially confined quasi-stationary two-body configurations.
Then two particles remain close while the third moves away. The wave function
may contain mixtures which produce coherence effects at small distances, but
the energy distributions can still be added incoherently. Two-neutron halos are
discussed in details and illustrated by the $2^+$ resonance in $^{6}$He. The
dynamic evolution of the decay process is discussed.",0512003v1
2002-02-15,Complex Response Function of Magnetic Resonance Spectrometers,"A vectorial analysis of magnetic resonance spectrometers, based on traveling
wave resonators and including the reference arm and the automatic control of
frequency, has been developed. The proposed model, valid also for stationary
wave resonators, gives the response function of the spectrometer for any
working condition, including scalar detectors with arbitrary response law and
arbitrary excitation frequency. The purely dispersive and purely absorptive
linear responses are discussed in detail for different scalar detectors. The
developed approach allows for optimizing the performances of the spectrometer
and for obtaining the intrinsic lineshape of the sample in a very broad range
of working conditions. More complex setups can be modeled following the
proposed scheme.",0202045v3
2004-10-16,Plasma heating due to X-B mode conversion in a cylindrical ECR plasma system,"Extra Ordinary (X) mode conversion to Bernstein wave near Upper Hybrid
Resonance (UHR) layer plays an important role in plasma heating through
cyclotron resonance. Wave generation at UHR and parametric decay at high power
has been observed during Electron Cyclotron Resonance (ECR) heating experiments
in toroidal magnetic fusion devices. A small linear system with ECR and UHR
layer within the system has been used to conduct experiments on X-B conversion
and parametric decay process as a function of system parameters. Direct probing
{\em in situ} is conducted and plasma heating is evidenced by soft x-ray
emission measurement. Experiments are performed with hydrogen plasma produced
with 160-800 W microwave power at 2.45 GHz of operating frequency at $10^{-3}$
mbar pressure. The axial magnetic field required for ECR is such that the
resonant surface (B = 875 G) is situated at the geometrical axis of the plasma
system. Experimental results will be presented in the paper.",0410112v2
2006-04-04,Vertical beaming of wavelength-scale photonic crystal resonators,"We report that $> 80%$ of the photons generated inside a photonic crystal
slab resonator can be funneled within a small divergence angle of $\pm
30^\circ$. The far-field radiation properties of a photonic crystal slab
resonant mode are modified by tuning the cavity geometry and by placing a
reflector below the cavity. The former method directly shapes the near-field
distribution so as to achieve directional and linearly-polarized far-field
patterns. The latter modification takes advantage of the interference effect
between the original waves and the reflected waves to enhance the
energy-directionality. We find that, regardless of the slab thickness, the
optimum distance between the slab and the reflector closely equals one
wavelength of the resonance under consideration. We have also discussed an
efficient far-field simulation algorithm based on the finite-difference
time-domain method and the near- to far-field transformation.",0604019v2
2000-06-10,Dynamical description of the buildup process in resonant tunneling: Evidence of exponential and non-exponential contributions,"The buildup process of the probability density inside the quantum well of a
double-barrier resonant structure is studied by considering the analytic
solution of the time dependent Schr\""{o}dinger equation with the initial
condition of a cutoff plane wave. For one level systems at resonance condition
we show that the buildup of the probability density obeys a simple charging up
law, $| \Psi (\tau) / \phi | =1-e^{-\tau /\tau_0},$ where $\phi$ is the
stationary wave function and the transient time constant $\tau_0$ is exactly
two lifetimes. We illustrate that the above formula holds both for symmetrical
and asymmetrical potential profiles with typical parameters, and even for
incidence at different resonance energies. Theoretical evidence of a crossover
to non-exponential buildup is also discussed.",0006052v1
2004-07-13,Stark Effect in Lax-Phillips Theory,"The scattering theory of Lax and Phillips, originally developed to describe
resonances associated with classical wave equations, has been recently extended
to apply as well to the case of the Schroedinger equation in the case that the
wave operators for the corresponding Lax-Phillips theory exist. It is known
that the bound state levels of an atom become resonances (spectral
enhancements) in the continuum in the presence of an electric field (in all
space) in the quantum mechanical Hilbert space. Such resonances appear as
states in the extended Lax-Phillips Hilbert space. We show that for a simple
version of the Stark effect, these states can be explicitly computed, and
exhibit the (necessarily) semigroup property of decay in time. The widths and
location of the resonances are those given by the poles of the resolvent of the
standard quantum mechanical form.",0407088v1
2007-08-19,"Unusual Resonators: Plasmonics, Metamaterials, and Random Media","Superresolution, extraordinary transmission, total absorption, and
localization of electromagnetic waves are currently attracting growing
attention. These phenomena are related to different physical objects and are
usually studied within the context of different, sometimes rather
sophisticated, physical approaches. Remarkably, all these seemingly unrelated
phenomena owe their origin to the same underlying physical mechanism - wave
interaction with an open resonator. Here we show that it is possible to
describe all of these effects in a unified way, mapping each system onto a
simple resonator model. Such description provides a thorough understanding of
the phenomena, explains all the main features of their complex behaviour, and
enables to control the system via the resonator parameters: eigenfrequencies,
Q-factors, and coupling coefficients.",0708.2653v3
2007-08-24,Resonant electromagnetic emission from intrinsic Josephson-junction stacks with laterally modulated Josephson critical current,"Intrinsic Josephson-junction stacks realized in mesas fabricated out of
high-temperature superconductors may be used as sources of coherent
electromagnetic radiation in the terahertz range. The major challenge is to
synchronize Josephson oscillations in all junctions in the stack to get
significant radiation out of the crystal edge parallel to the c axis. We
suggest a simple way to solve this problem via artificially prepared lateral
modulation of the Josephson critical current identical in all junctions. In
such a stack phase oscillations excite the in-phase Fiske mode when the
Josephson frequency matches the Fiske-resonance frequency which is set by the
stack lateral size. The powerful almost standing electromagnetic wave is
excited inside the crystal in the resonance. This wave is homogeneous across
the layers meaning that the oscillations are synchronized in all junctions in
the stack. We evaluate behavior of the I-V characteristics and radiated power
near the resonance for arbitrary modulation and find exact solutions for
several special cases corresponding to symmetric and asymmetric modulations of
the critical current.",0708.3269v4
2009-04-01,Nanogap Transducer for Broadband Gravitational Wave Detection,"By changing from a resonant multimode paradigm to a free mass paradigm for
transducers in resonant mass gravitational wave detection, an array of six
spheres can achieve a sensitivity response curve competitive with
interferometers, being as sensitive as GEO600 and TAMA300 in the 3 to 6 kHz
band and more sensitive than LIGO for 50 percent of the 6 to 10 kHz band. We
study how to assemble a klystron resonant cavity that has a 1 nm gap by
understanding the stability of the forces applied at it (Casimir force, elastic
force, weight). This approach has additional benefits. First, due to the
relatively inexpensive nature of this technology (around US$ 1 million), it is
accessible to a broader part of the world scientific community. Additionally,
spherical resonant mass detectors have the ability to discern both the
direction and polarization resolutions.",0904.0055v2
2009-11-11,Saturation of Stationary Inversion States in a Three-Level Traveling-Wave Quantum Amplifier with Bistable Resonator Pumping,"The inversion states of a saturated traveling-wave three-level quantum
paramagnetic amplifier have been investigated under conditions of bistable
resonator pumping. The equations of motion for the vectorial order parameter
have been obtained using adiabatic elimination of fast variables. The exact
solutions for stationary inversion states have been found from these equations.
For high-quality pump resonators, the isolated and the semi-isolated branches
of the inversion ratio have been revealed in stationary solutions. The
existence of the semi-isolated branches means a possibility of collapse of the
inversion state under influence of a saturating signal. Revival of inversion is
possible in this case only by the hard excitation of the pump system. This
nonlinear phenomenon is of a qualitatively another nature than one described by
us in arXiv:0901.0449v1 [nlin.AO], and may be observed at moderate Q-factor of
pump resonator.",0911.2124v1
2010-05-13,Multi-Atomic Mirror for Perfect Reflection of Single Photons in A Wide Band of Frequency,"A resonant two level atom doped in one dimensional waveguide behaves as a
mirror, but this single-atom ""mirror"" can only reflect single photon perfectly
at a specific frequency. For a one dimensional coupled-resonator waveguide, we
propose to extend the perfect reflection region from a specific frequency to a
wide band by placing many atoms individually in the resonators in a finite
coordinate region of the waveguide. Such a doped resonator array promises us to
control the propagation of a practical photon wave packet with certain momentum
distribution instead of a single photon, which is ideally represented by a
plane wave with specific momentum. The studies based on the discrete-coordinate
scattering theory display that such hybrid structure indeed provides a
near-perfect reflection for single photon in a wide band. We also calculated
photon group velocity distribution, which shows that the perfect reflection
with wide band exactly corresponds to the stopping light region.",1005.2274v3
2011-05-03,Theoretical study of the two-proton halo candidate $^{17}$Ne including contributions from resonant continuum and pairing correlations,"With the relativistic Coulomb wave function boundary condition, the energies,
widths and wave functions of the single proton resonant orbitals for $^{17}$Ne
are studied by the analytical continuation of the coupling constant (ACCC)
approach within the framework of the relativistic mean field (RMF) theory.
Pairing correlations and contributions from the single-particle resonant
orbitals in the continuum are taken into consideration by the resonant
Bardeen-Cooper-Schrieffer (BCS) approach, in which constant pairing strength is
used. It can be seen that the fully self-consistent calculations with NL3 and
NLSH effective interactions mostly agree with the latest experimental
measurements, such as binding energies, matter radii, charge radii and
densities. The energy of $\pi$2s$_{1/2}$ orbital is slightly higher than that
of $\pi1d_{5/2}$ orbital, and the occupation probability of the
$(\pi$2s$_{1/2})^2$ orbital is about 20%, which are in accordance with the
shell model calculation and three-body model estimation.",1105.0504v4
2012-01-16,Super-sharp resonances in chaotic wave scattering,"Wave scattering in chaotic systems can be characterized by its spectrum of
resonances, $z_n=E_n-i\frac{\Gamma_n}{2}$, where $E_n$ is related to the energy
and $\Gamma_n$ is the decay rate or width of the resonance. If the
corresponding ray dynamics is chaotic, a gap is believed to develop in the
large-energy limit: almost all $\Gamma_n$ become larger than some $\gamma$.
However, rare cases with $\Gamma<\gamma$ may be present and actually dominate
scattering events. We consider the statistical properties of these super-sharp
resonances. We find that their number does not follow the fractal Weyl law
conjectured for the bulk of the spectrum. We also test, for a simple model, the
universal predictions of random matrix theory for density of states inside the
gap and the hereby derived probability distribution of gap size.",1201.3326v1
2012-01-23,Nonlinear problems of complex natural systems: Sun and climate dynamics,"Universal role of the nonlinear one-third subharmonic resonance mechanism in
generation of the strong fluctuations in such complex natural dynamical systems
as global climate and global solar activity is discussed using wavelet
regression detrended data. Role of the oceanic Rossby waves in the year-scale
global temperature fluctuations and the nonlinear resonance contribution to the
El Nino phenomenon have been discussed in detail. The large fluctuations of the
reconstructed temperature on the millennial time-scales (Antarctic ice cores
data for the past 400,000 years) are also shown to be dominated by the
one-third subharmonic resonance, presumably related to Earth precession effect
on the energy that the intertropical regions receive from the Sun. Effects of
Galactic turbulence on the temperature fluctuations are discussed in this
content. It is also shown that the one-third subharmonic resonance can be
considered as a background for the 11-years solar cycle, and again the global
(solar) rotation and chaotic propagating waves play significant role in this
phenomenon. Finally, a multidecadal chaotic coherence between the detrended
solar activity and global temperature has been briefly discussed.",1201.4679v1
2013-06-17,Continuous reversal of Hanle resonances of counter-propagating pulse and continuous-wave field,"In this work we study propagation dynamics of the two counter-propagating
lasers, the continuous-wave (CW) laser and the pulse of another laser, when
both lasers are tuned to the $F_{g}=2 \rightarrow F_{e}=1$ transition in
$^{87}$Rb, and therefore can develop Hanle electromagnetically induced
transparency (EIT) in Rb vapor. We calculate transmission of both lasers as a
function of applied magnetic field, and investigate how the propagation of the
pulse affects the transmission of the CW laser. And vice versa, we have found
conditions when the Gaussian pulse can either pass unchanged, or be
significantly absorbed in the vacuum Rb cell. This configuration is therefore
suitable for the convenient control of the pulse propagation and the system is
of interest for optically switching of the laser pulses. In terms of the
corresponding shapes of the coherent Hanle resonances, this is equivalent to
turning the coherent resonance from Hanle EIT into electromagnetically induced
absorption (EIA) peak. There is the range of intensities of both CW laser and
the laser pulse when strong drives of atomic coherences allow two lasers to
interact with each other through atomic coherence and can simultaneously
reverse signs of Hanle resonances of both.",1306.3944v1
2013-07-11,Resonant enhancement of Anderson localization: Analytical approach,"We study localization properties of the eigenstates and wave transport in
one-dimensional system consisting of a set of barriers/wells of fixed thickness
and random heights. The inherent peculiarity of the system resulting in the
enhanced Anderson localization, is the presence of the resonances emerging due
to the coherent interaction of the waves reflected from the interfaces between
wells/barriers. Our theoretical approach allows to derive the localization
length in infinite samples both out of the resonances and close to them. We
examine how the transport properties of finite samples can be described in
terms of this length. It is shown that the analytical expressions obtained by
standard methods for continuous random potentials can be used in our discrete
model, in spite of the presence of resonances that cannot be described by
conventional theories. We also discuss whether the single parameter scaling is
valid in view of the suggested modification of the theory. All our results are
illustrated with numerical data manifesting an excellent agreement with the
theory.",1307.3202v1
2013-10-30,Sub-Micron Positioning of Trapped Ions with Respect to the Absolute Center of a Standing Wave Cavity Field,"We demonstrate that it is possible, with sub-micron precision, to locate the
absolute center of a Fabry-P\'erot resonator oriented along the rf-field-free
axis of a linear Paul trap through the application of two simultaneously
resonating optical fields. In particular, we apply a probe field, which is
near-resonant with an electronic transition of trapped ions, simultaneously
with an off-resonant strong field acting as a periodic AC Stark-shifting
potential. Through the resulting spatially modulated fluorescence signal we can
find the cavity center of an 11.7 mm-long symmetric Fabry- P\'erot cavity with
a precision of $\pm$135 nm, which is smaller than the periodicity of the
individual standing wave fields. This can e.g. be used to position the minimum
of the axial trap potential with respect to the center of the cavity at any
location along the cavity mode.",1310.8333v1
2013-11-13,Recent progresses on the pseudospin symmetry in single particle resonant states,"The pseudospin symmetry (PSS) is a relativistic dynamical symmetry directly
connected with the small component of the nucleon Dirac wave function. Much
effort has been made to study this symmetry in bound states. Recently, a
rigorous justification of the PSS in single particle resonant states was
achieved by examining the asymptotic behaviors of the radial Dirac wave
functions: The PSS in single particle resonant states in nuclei is conserved
exactly when the attractive scalar and repulsive vector potentials have the
same magnitude but opposite sign. Several issues related to the exact
conservation and breaking mechanism of the PSS in single particle resonances
were investigated by employing spherical square well potentials in which the
PSS breaking part can be well isolated in the Jost function. A threshold effect
in the energy splitting and an anomaly in the width splitting of pseudospin
partners were found when the depth of the square well potential varies from
zero to a finite value.",1311.3180v1
2013-12-12,Precision spectroscopy with COMPASS and the observation of a new iso-vector resonance,"We report on the results of a novel partial-wave analysis based on $50\cdot
10^6$ events from the reaction $\pi^- + p \to \pi^-\pi-^\pi^+ +
p_\text{recoil}$ at 190 $\text{GeV/c}$ incoming beam momentum using the COMPASS
spectrometer. A separated analysis in bins of $m_{3\pi}$ and four-momentum
transfer $t'$ reveals the interference of resonant and non-resonant particle
production and allows their spectral separation. Besides well known resonances
we observe a new iso-vector meson $a_1(1420)$ at a mass of 1420
$\text{MEV\c}^2$ in the $f_0(980)\pi$ final state only, the origin of which is
unclear. We have also examined the structure of the $0^{++}$ $\pi\pi$-isobar in
the $J^{PC}=0^{-+}, 1^{++}, 2^{-+}$ three pion waves. This clearly reveals the
various $0^{++}$ $\pi\pi$-isobar components and its correlation to the decay of
light mesons.",1312.3678v1
2013-12-28,Reflection resonances in surface-disordered waveguides: strong higher-order effects of the disorder,"We study coherent wave scattering through waveguides with a step-like surface
disorder and find distinct enhancements in the reflection coefficients at
well-defined resonance values. Based on detailed numerical and analytical
calculations, we can unambiguously identify the origin of these reflection
resonances to be higher-order correlations in the surface disorder profile
which are typically neglected in similar studies of the same system. A
remarkable feature of this new effect is that it relies on the longitudinal
correlations in the step profile, although individual step heights are random
and thus completely uncorrelated. The corresponding resonances are very
pronounced and robust with respect to ensemble averaging, and lead to an
enhancement of wave reflection by more than one order of magnitude.",1312.7458v1
2013-12-30,Plasmonic coupled-cavity system for enhancement of surface plasmon localization in plasmonic detectors,"A plasmonic coupled-cavity system, which consists of a quarter-wave coupler
cavity, a resonant Fabry-Perot detector nanocavity, and an off-resonant
reflector cavity, is used to enhance the localization of surface plasmons in a
plasmonic detector. The coupler cavity is designed based on transmission line
theory and wavelength scaling rules in the optical regime, while the reflector
cavity is derived from off-resonant resonator structures to attenuate
transmission of plasmonic waves. We observed strong coupling of the cavities in
simulation results, with an 86% improvement of surface plasmon localization
achieved. The plasmonic coupled-cavity system may find useful applications in
areas of nanoscale photodetectors, sensors, and an assortment of
plasmonic-circuit devices.",1312.7632v1
2015-02-25,Calculating broad neutron resonances in a cut-off Woods-Saxon potential,"In a cut-off Woods-Saxon (CWS) potential with realistic depth $S$-matrix
poles being far from the imaginary wave number axis form a sequence where the
distances of the consecutive resonances are inversely proportional with the
cut-off radius value, which is an unphysical parameter. Other poles lying
closer to the imaginary wave number axis might have trajectories with irregular
shapes as the depth of the potential increases. Poles being close repel each
other, and their repulsion is responsible for the changes of the directions of
the corresponding trajectories. The repulsion might cause that certain
resonances become antibound and later resonances again when they collide on the
imaginary axis. The interaction is extremely sensitive to the cut-off radius
value, which is an apparent handicap of the CWS potential.",1502.07111v5
2015-06-09,Nonlinear waves in a strongly nonlinear resonant granular chain,"We explore a recently proposed locally resonant granular system bearing
harmonic internal resonators in a chain of beads interacting via Hertzian
elastic contacts. In this system, we propose the existence of two types of
configurations: (a) small-amplitude periodic traveling waves and (b)
dark-breather solutions, i.e., exponentially localized, time periodic states
mounted on top of a non-vanishing background. We also identify conditions under
which the system admits long-lived bright breather solutions. Our results are
obtained by means of an asymptotic reduction to a suitably modified version of
the so-called discrete p-Schr{\""o}dinger (DpS) equation, which is established
as controllably approximating the solutions of the original system for large
but finite times (under suitable assumptions on the solution amplitude and the
resonator mass). The findings are also corroborated by detailed numerical
computations. A remarkable feature distinguishing our results from other
settings where dark breathers are observed is the complete absence of
precompression in the system, i.e., the absence of a linear spectral band.",1506.02827v1
2015-07-17,Rabi oscillations in two-level systems beyond the rotating-wave approximation,"Here we use perturbation techniques based on the averaging method to
investigate Rabi oscillations in cw and pulse-driven two-level systems (TLS's).
By going beyond the rotating-wave approximation, especifically to second-order
in perturbation, we obtain the Bloch-Siegert shift of the TLS resonant
frequency, in which the resonant frequency increases with the driving field
amplitude. This frequency shift implies that short resonant $\pi$-pulses in
which the Rabi frequency is approximately 40\% or higher of the transition
frequency do not achieve complete inversion in TLS's. Hence, guided by
analytical results based on the averaging technique, we propose two methods for
obtaining population inversions in the TLS driven by short $\pi$-pulses: one
with chirping and the other with pulse shaping and near resonance blue-shifted
detuning. Both methods minimize dephasing due to the Bloch-Siegert shift,
reduce the dependance of the excitation of the TLS on the pulse phase, and are
very effective in achieving complete population inversions.",1507.05124v1
2015-09-10,"A weighted estimate for two dimensional Schrodinger, matrix schrodinger and wave equations with resonance of first kind at zero energy","We study the two dimensional Schr\""odinger operator, $H=-\Delta+V$, in the
weighted L^1(\R^2) \rightarrow L^{\infty}(\R^2) setting when there is a
resonance of the first kind at zero energy. In particular, we show that if
|V(x)|\les \la x \ra ^{-3-} and there is only s-wave resonance at zero of H,
then \big\| w^{-1} \big( e^{itH}P_{ac} f - {\f 1 t } F f \big) \big\| _{\infty}
\leq \frac {C} {|t| (\log|t|)^2 } \|wf\|_1 |t|>2, with w(x)=\log^2(2+|x|). Here
Ff=c \psi\la f,\psi \ra, where \psi is an s-wave resonance function. We also
extend this result to matrix Schr\""odinger and wave equations with potentials
under similar conditions.",1509.03204v1
2015-10-07,Supertransmission channel for an intrinsic localized mode in a 1D nonlinear physical lattice,"It is well known that a moving intrinsic localized mode (ILM) in a nonlinear
physical lattice looses energy because of the resonance between it and the
underlying small amplitude plane wave spectrum. By exploring the Fourier
transform (FT) properties of the nonlinear force of a running ILM in a driven
and damped 1D nonlinear lattice, as described by a 2-D wavenumber and frequency
map, we quantify the magnitude of the resonance where the small amplitude
normal mode dispersion curve and the FT amplitude components of the ILM
intersect. We show that for a traveling ILM characterized by a specific
frequency and wavenumber, either inside or outside the plane wave spectrum, and
for situations where both onsite and intersite nonlinearity occur, either of
the hard or soft type, the strength of this resonance depends on the specific
mix of the two nonlinearities. Examples are presented demonstrating that by
engineering this mix the resonance can be greatly reduced. The end result is a
supertransmission channel for either a driven or undriven ILM in a
nonintegrable, nonlinear yet physical lattice.",1510.01810v1
2015-12-15,Pulsed Rydberg four-wave mixing with motion-induced dephasing in a thermal vapor,"We report on time-resolved pulsed four-wave mixing (FWM) signals in a thermal
Rubidium vapor involving a Rydberg state. We observe FWM signals with dephasing
times up to 7 ns, strongly dependent on the excitation bandwidth to the Rydberg
state. The excitation to the Rydberg state is driven by a pulsed two-photon
transition on ns time scales. Combined with a third cw de-excitation laser, a
strongly directional and collective emission is generated according to a
combination of the phase matching effect and averaging over Doppler classes. In
contrast to a previous report [1] using off-resonant FWM, at a resonant FWM
scheme we observe additional revivals of the signal shortly after the incident
pulse has ended. We infer that this is a revival of motion-induced constructive
interference between the coherent emissions of the thermal atoms. The resonant
FWM scheme reveals a richer temporal structure of the signals, compared to
similar, but off-resonant excitation schemes. A simple explanation lies in the
selectivity of Doppler classes. Our numerical simulations based on a four-level
model including a whole Doppler ensemble can qualitatively describe the data.",1512.04843v1
2016-01-19,Resonances and antibound states of Pöschl-Teller potential: Ladder operators and SUSY partners,"We analyze the one dimensional scattering produced by all variations of the
P\""oschl-Teller potential, i.e., potential well, low and high barriers. We show
that the P\""oschl-Teller well and low barrier potentials have no resonance
poles, but an infinite number of simple poles along the imaginary axis
corresponding to bound and antibound states. A quite different situation arises
on the P\""oschl-Teller high barrier potential, which shows an infinite number
of resonance poles and no other singularities. We have obtained the explicit
form of their associated Gamow states. We have also constructed ladder
operators connecting wave functions for bound and antibound states as well as
for resonance states. Finally, using wave functions of Gamow and antibound
states in the factorization method, we construct some examples of
supersymmetric partners of the P\""oschl-Teller Hamiltonian.",1601.05134v1
2016-05-25,Nonlinear and Quantum Optics with Whispering Gallery Resonators,"Optical Whispering Gallery Modes (WGMs) derive their name from a famous
acoustic phenomenon of guiding a wave by a curved boundary observed nearly a
century ago. This phenomenon has a rather general nature, equally applicable to
sound and all other waves. It enables resonators of unique properties
attractive both in science and engineering. Very high quality factors of
optical WGM resonators persisting in a wide wavelength range spanning from
radio frequencies to ultraviolet light, their small mode volume, and tunable
in- and out- coupling make them exceptionally efficient for nonlinear optical
applications. Nonlinear optics facilitates interaction of photons with each
other and with other physical systems, and is of prime importance in quantum
optics. In this paper we review numerous applications of WGM resonators in
nonlinear and quantum optics. We outline the current areas of interest,
summarize progress, highlight difficulties, and discuss possible future
development trends in these areas.",1605.07972v2
2016-09-17,Transmodal Fabry-Pérot Resonance: Theory and Realization with Elastic Metamaterials,"We discovered a new transmodal Fabry-P\'erot resonance that one elastic-wave
mode is maximally transmitted to another when the phase difference of two
dissimilar modes through an anisotropic layer is exactly odd multiples of
{\pi}. Unlike the well-established Fabry-P\'erot resonance, the transmodal
resonance must involve two coupled elastic-wave modes, longitudinal and shear.
The formation of wiggly transmodal transmission spectra is due to structural
instability appearing in anisotropic mode-coupled elastic-media. Experiments
with elastic metamaterials confirmed our findings which can play a critical
role in shear-mode ultrasound applications.",1609.05266v1
2016-09-22,Double polarisation experiments in meson photoproduction,"One of the remaining challenges within the standard model is to gain a good
understanding of QCD in the non-perturbative regime. A key step towards this
aim is baryon spectroscopy, investigating the spectrum and the properties of
baryon resonances. To gain access to resonances with small $\pi N$ partial
width, photoproduction experiments provide essential information. Partial wave
analyses need to be performed to extract the contributing resonances. Here, a
complete experiment is required to unambiguously determine the contributing
amplitudes. This involves the measurement of carefully chosen single and double
polarisation observables. In a joint endeavour by MAMI, ELSA, and Jefferson
Laboratory, a new generation of experiments with polarised beams, polarised
proton and neutron targets, and $4\pi$ particle detectors have been performed
in recent years. Many results of unprecedented quality were recently published
by all three experiments, and included by the various partial wave analysis
groups in their analyses, leading to substantial improvements, e.g. a more
precise determination of resonance parameters. An overview of recent results is
given, with an emphasis on results from the CBELSA/TAPS experiment, and their
impact on our understanding of the nucleon excitation spectrum is discussed.",1609.06946v1
2016-10-17,Broadband achromatic anomalous mirror in near-IR and visible frequency range,"The anomalous achromatic mirror operating in near-IR and visible frequency
range was designed using an array of metal-insulator-metal (MIM) resonators. An
incident wave interacting with MIM resonator experiences phase shift that is
equal to the optical path travelled by the gap plasmon, excited by the wave.
The phase gradient along the mirror surface is created through the difference
in plasmons optical paths in resonators of different lengths. In the frequency
region well below the plasma frequency of the metal, the phase gradient is a
linear function of frequency, and thus the mirror operates in achromatic
regime, i.e. reflection angle does not depend on the radiation frequency. Using
silver-air-silver resonators, we predicted that the mirror can steer normally
incident beam to angles as large as 40$^{\circ}$ with high radiation efficiency
(exceeding 98 $\%$) and small Joule losses (below 10 $\%$).",1610.05236v1
2017-07-25,A positive-definite form of bounce-averaged quasilinear velocity diffusion for the parallel inhomogeneity in a tokamak,"In this paper, the analytical form of the quasilinear diffusion coefficients
is modified from the Kennel-Engelmann diffusion coefficients to guarantee the
positive definiteness of its bounce average in a toroidal geometry. By
evaluating the parallel inhomogeneity of plasmas and magnetic fields in the
trajectory integral, we can ensure the positive definiteness and help
illuminate some non-resonant toroidal effects in the quasilinear diffusion.
When the correlation length of the plasma-wave interaction is comparable to the
magnetic field variation length, the variation becomes important and the
parabolic variation at the outer-midplane, the inner-midplane, and trapping
tips can be evaluated by Airy functions. The new form allows the coefficients
to include both resonant and non-resonant contributions, and the correlations
between the consecutive resonances and in many poloidal periods. The
positive-definite form is implemented in a wave code TORIC and we present an
example for ITER using this form.",1707.08030v2
2017-08-16,The REsonant Multi-Pulse Ionization injection,"The production of high-quality electron bunches in Laser Wake Field
Acceleration relies on the possibility to inject ultra-low emittance bunches in
the plasma wave. In this paper we present a new bunch injection scheme in which
electrons extracted by ionization are trapped by a large-amplitude plasma wave
driven by a train of resonant ultrashort pulses. In the REsonant Multi-Pulse
Ionization (REMPI) injection scheme, the main portion of a single ultrashort
(e.g Ti:Sa) laser system pulse is temporally shaped as a sequence of resonant
sub-pulses, while a minor portion acts as an ionizing pulse. Simulations show
that high-quality electron bunches with normalized emittance as low as $0.08$
mm$\times$mrad and $0.65\%$ energy spread can be obtained with a single
present-day 100TW-class Ti:Sa laser system.",1708.04957v1
2017-09-20,Resonant quenching of plasmon energy dissipation in a metal film with nonlocal dielectric response,"Evanescent waves in a metal thin film with nonlocality are found to propagate
in normal direction to film surface with quenched (to zero) energy dissipation
associated with intra-band electron transitions when wave numbers satisfy a
resonant condition. It is shown that resonant quenching of energy dissipation
(RQED) effect occurs in metal films with thicknesses of less or larger than,
but still on the order of, the nonlocality scale length. RQED ceases to exist
in metal films whose thickness exceeds a cutoff length or in metal films with
local dielectric permittivity. Resonant quenching of energy dissipation is
caused by destructive interference of partial contributions to electric
displacement field, spatially dispersed over thin film thickness. It is
demonstrated that RQED effect can be used for designing a new type of plasmonic
waveguides, such as a slit waveguide representing a metal film with a narrow
slit filled with a dielectric, to achieve near zero propagation losses for
plasmonic modes with few nanometer scale confinement.",1709.06701v1
2018-06-19,Resonant Localized Modes in Electrical Lattices with Second Neighbor Coupling,"We demonstrate experimentally and corroborate numerically that an electrical
lattice with nearest-neighbor and second-neighbor coupling can simultaneously
support long-lived coherent structures in the form of both standard intrinsic
localized modes (ILMs), as well as resonant ILMs. In the latter case, the wings
of the ILM exhibit oscillations due to resonance with a degenerate plane-wave
mode. This kind of localized mode has also been termed nanopteron. Here we show
experimentally and using realistic simulations of the system that the
nanopteron can be stabilized via both direct and subharmonic driving. In the
case of excitations at the zone center (i.e., at wavenumber $k=0$), we observed
stable ILMs, as well as a periodic localization pattern in certain driving
regimes. In the zone boundary case (of wavenumber $k=\pi/a$, where $a$ is the
lattice spacing), the ILMs are always resonant with a plane-wave mode, but can
nevertheless be stabilized by direct (staggered) and subharmonic driving.",1806.07494v1
2018-11-01,Approximate cloaking for electromagnetic waves via transformation optics: cloaking vs infinite energy,"We study the approximate cloaking via transformation optics for
electromagnetic waves in the time harmonic regime in which the cloaking device
{\it only} consists of a layer constructed by the mapping technique. Due to the
fact that no-lossy layer is required, resonance might appear and the analysis
is delicate. We analyse both non-resonant and resonant cases. In particular, we
show that the energy can blow up inside the cloaked region in the resonant case
and/whereas cloaking is {\it achieved} in {\it both} cases. Moreover, the
degree of visibility {\it depends} on the compatibility of the source inside
the cloaked region and the system. These facts are new and distinct from known
mathematical results in the literature.",1811.00406v1
2019-11-22,I=3/2 nucleon-pion scattering and the Delta(1232) resonance on 2+1 flavor CLS ensembles using the stochastic LapH method,"Calculations of the elastic $I=\frac{3}{2}$ nucleon-pion scattering phase
shifts on two lattice QCD ensembles with $m_\pi=200\mathrm{MeV}$ and
$280\mathrm{MeV}$ are presented. The ensembles both employ $N_\mathrm{f} = 2+1$
Wilson clover fermions. We determine the $\Delta(1232)$ resonance parameters
from a finite volume scattering analysis. In one study the single partial wave
simplification is employed to compute the $p$-wave amplitude while in the other
we treat the partial wave mixing between $s$- and $p$-wave contributions.
Fitting our data to a Breit-Wigner resonance model we find $m_\Delta/m_\pi =
7.13(9)$ and $4.75(5)$ on the two ensembles respectively, showing that for a
lighter quark mass the resonance mass moves from near the $N\pi$ threshold to
near the $N\pi\pi$ threshold, in agreement with experiment.",1911.10021v1
2018-07-05,Bound states in the continuum and high-Q resonances supported by a dielectric ridge on a slab waveguide,"We investigate the diffraction of guided modes of a dielectric slab waveguide
on a simple integrated structure consisting of a single dielectric ridge on the
surface of the waveguide. Numerical simulations based on aperiodic rigorous
coupled-wave analysis demonstrate the existence of sharp resonant features and
bound states in the continuum (BICs) in the reflectance and the transmittance
spectra occurring at oblique incidence of a TE-polarized guided mode on the
ridge. Using the effective index method, we explain the resonances by the
excitation of the cross-polarized modes of the ridge. The formation of the BICs
is confirmed using a theoretical model based on the coupled-wave theory. The
model suggests that the BICs occur due to coupling of quasi-TE and quasi-TM
modes of the structure. Simple analytical expressions for the angle of
incidence and the ridge width predicting the location of the BICs are obtained.
The existence of high-Q resonances and BICs makes the considered integrated
structure promising for filtering, sensing, transformation of optical signals,
and enhancing nonlinear light-matter interactions.",1807.01888v1
2018-07-12,Eta and Etaprime Photoproduction on the Nucleon with the Isobar Model EtaMAID2018,"The isobar model EtaMAID has been updated with new and high precision data
for eta and etaprime photoproduction on protons and neutrons from MAMI, ELSA,
GRAAL and CLAS. The background is described in a recently developed Regge-cut
model, and for the resonance part the whole list of nucleon resonances has been
investigated with 21 N* states contributing to eta photoproduction and 12 N*
states contributing to etaprime photoproduction. A new approach is discussed to
avoid double counting in the overlap region of Regge and resonances. A
comparison is done among four newly updated partial waves analyses for
observables and partial waves. Finally, the possibility of a narrow resonance
near W=1900 MeV is discussed, that would be able to explain unexpected energy
and angular dependence of observables in p(gamma,etaprime)p near etaprime
threshold.",1807.04525v2
2018-07-18,Gravitational wave forest from string axiverse,"Axions predicted in string theory may have a scalar potential which has a
much shallower potential region than the conventional cosine potential. We
first show that axions which were located at such shallow potential regions
generically undergo prominent resonance instabilities: the well-known narrow
resonance and/or the flapping resonance, which has not been well investigated.
We also study non-linear dynamics of axions caused by these resonance
instabilities based on lattice simulation. We find that string axions in
various mass ranges generate gravitational waves (GWs) with peaks at various
frequencies determined by the mass scales, dubbed the GW forest. This may allow
us to explore string axiverse through future multi-frequency GW observations.
We also investigate GWs produced by the axion which accounts for present dark
matter component.",1807.07037v1
2018-12-18,Polygram Stars: Resonant Tidal Excitation of Fundamental Oscillation Modes in Asynchronous Stellar Coalescence,"The prevalence of binary stars at close separations implies that many of
these systems will interact or merge during the binary's lifetime. This paper
presents hydrodynamic simulations of the scenario of binary coalescence through
unstable mass transfer, which drives the pair to closer separations. When the
donor star does not rotate synchronously with respect to the orbit, dynamical
tidal waves are excited in its envelope. We show that resonance crossings with
high azimuthal-order $(m\sim3$ to $6$) fundamental modes induce a visible
""polygram"" distortion to the star. As the binary orbit tightens, the system
sweeps through resonance with modes of decreasing azimuthal order, which are
selectively excited. We compare our hydrodynamic simulations to predictions
from linear theory of resonant mode excitation. The linear theory provides an
estimate of mode amplitudes to within a factor of two, even as the oscillations
become quite non-linear as the stars coalesce. We estimate that a wave with 10%
radial amplitude generates approximately 1% photometric variability; this may
be detectible if such a binary coalescence is caught in action by future
photometric all-sky surveys.",1812.07594v1
2020-04-06,Dissipative Rabi model in the dispersive regime,"The dispersive regime of circuit QED is the main workhorse for todays quantum
computing prototypes based on superconducting qubits. Analytic descriptions of
this model typically rely on the rotating wave approximation of the interaction
between the qubits and resonators, using the Jaynes-Cummings model as starting
point for the dispersive transformation. Here we present analytic results on
the dispersive regime of the dissipative Rabi model, without taking the
rotating wave approximation of the underlying Hamiltonian. Using a recently
developed hybrid perturbation theory based on the expansion of the time
evolution on the Keldysh contour [Phys. Rev. A 95, 013847 (2017)], we derive
simple analytic expressions for all experimentally relevant dynamical
parameters like dispersive shift and resonator induced Purcell decay rate,
focussing our analysis on a generic multi-level qubit. The analytical equations
are easily tractable and reduce to the known Jaynes-Cummings results in the
relevant limit. They however show qualitative differences at intermediate and
large detuning, allowing for more accurate modelling of the interaction between
superconducting qubits and resonators. In the limit of strong resonator
driving, our results additionally predict new types of drive induced qubit
dissipation and dephasing, not present in previous theories.",2004.02519v2
2020-04-25,A new spectral analysis of stationary random Schrödinger operators,"Motivated by the long-time transport properties of quantum waves in weakly
disordered media, the present work puts random Schr\""odinger operators into a
new spectral perspective. Based on a stationary random version of a Floquet
type fibration, we reduce the description of the quantum dynamics to a fibered
family of abstract spectral perturbation problems on the underlying probability
space. We state a natural resonance conjecture for these fibered operators: in
contrast with periodic and quasiperiodic settings, this would entail that Bloch
waves do not exist as extended states, but rather as resonant modes, and this
would justify the expected exponential decay of time correlations. Although
this resonance conjecture remains open, we develop new tools for spectral
analysis on the probability space, and in particular we show how ideas from
Malliavin calculus lead to rigorous Mourre type results: we obtain an
approximate dynamical resonance result and the first spectral proof of the
decay of time correlations on the kinetic timescale. This spectral approach
suggests a whole new way of circumventing perturbative expansions and
renormalization techniques.",2004.12025v3
2017-02-21,Synthetic phonons enable nonreciprocal coupling to arbitrary resonator networks,"Inducing nonreciprocal wave propagation is a fundamental challenge across a
wide range of physical systems in electromagnetics, optics, and acoustics.
Recent efforts to create nonreciprocal devices have departed from established
magneto-optic methods and instead exploited momentum based techniques such as
coherent spatiotemporal modulation of resonators and waveguides. However, to
date the nonreciprocal frequency responses that such devices can achieve have
been limited, mainly to either broadband or Lorentzian-shaped transfer
functions. Here we show that nonreciprocal coupling between waveguides and
resonator networks enables the creation of devices with customizable
nonreciprocal frequency responses. We create nonreciprocal coupling through the
action of synthetic phonons, which emulate propagating phonons and can scatter
light between guided and resonant modes that differ in both frequency and
momentum. We implement nonreciprocal coupling in microstrip circuits and
experimentally demonstrate both elementary nonreciprocal functions such as
isolation and gyration as well as reconfigurable, higher-order nonreciprocal
filters. Our results suggest nonreciprocal coupling as platform for a broad
class of customizable nonreciprocal systems, adaptable to all wave phenomena.",1702.06476v3
2017-09-29,Broadening of Cyclotron Resonance Conditions in the Relativistic Interaction of an Intense Laser with Overdense Plasmas,"The interaction of dense plasmas with an intense laser under a strong
external magnetic field has been investigated. When the cyclotron frequency for
the ambient magnetic field is higher than the laser frequency, the laser's
electromagnetic field is converted to the whistler mode that propagates along
the field line. Because of the nature of the whistler wave, the laser light
penetrates into dense plasmas with no cutoff density, and produces superthermal
electrons through cyclotron resonance. It is found that the cyclotron resonance
absorption occurs effectively under the broadened conditions, or a wider range
of the external field, which is caused by the presence of relativistic
electrons accelerated by the laser field. The upper limit of the ambient field
for the resonance increases in proportion to the square root of the
relativistic laser intensity. The propagation of a large-amplitude whistler
wave could raise the possibility for plasma heating and particle acceleration
deep inside dense plasmas.",1710.00099v1
2017-10-09,Acoustic double negativity induced by position correlations within a disordered set of monopolar resonators,"Using a Multiple Scattering Theory algorithm, we investigate numerically the
transmission of ultrasonic waves through a disordered locally resonant
metamaterial containing only monopolar resonators. By comparing the cases of a
perfectly random medium with its pair correlated counterpart, we show that the
introduction of short range correlation can substantially impact the effective
parameters of the sample. We report, notably, the opening of an acoustic
transparency window in the region of the hybridization band gap. Interestingly,
the transparency window is found to be associated with negative values of both
effective compressibility and density. Despite this feature being unexpected
for a disordered medium of monopolar resonators, we show that it can be fully
described analytically and that it gives rise to negative refraction of waves.",1710.03341v2
2017-10-10,Resonant Electron Impact Excitation of 3d levels in Fe$^{14+}$ and Fe$^{15+}$,"We present laboratory spectra of the $3p$--$3d$ transitions in Fe$^{14+}$ and
Fe$^{15+}$ excited with a mono-energetic electron beam. In the energy dependent
spectra obtained by sweeping the electron energy, resonant excitation is
confirmed as an intensity enhancement at specific electron energies. The
experimental results are compared with theoretical cross sections calculated
based on fully relativistic wave functions and the distorted-wave
approximation. Comparisons between the experimental and theoretical results
show good agreement for the resonance strength. A significant discrepancy is,
however, found for the non-resonant cross section in Fe$^{14+}$. %, which can
be considered as a fundamental cause of the line intensity ratio problem that
has often been found in both observatory and laboratory measurements. This
discrepancy is considered to be the fundamental cause of the previously
reported inconsistency of the model with the observed intensity ratio between
the $^3\!P_2$ -- $^3\!D_3$ and $^1\!P_1$ -- $^1\!D_2$ transitions.",1710.03548v3
2019-05-22,"Gravitational Wave ""Echo"" Spectra","Exotic compact objects may resemble black holes very closely while remaining
horizonless. They may be distinguished from black holes because they
effectively give rise to a resonant cavity for the propagation of low frequency
gravity waves. In a Green's function approach, the resonance structure appears
in a transfer function. The transfer function in turn is modulated by an
initial-condition-dependent source integral to obtain the observed spectrum. We
find that the source integral displays universal factors that tend to enhance
low and negative frequencies, and this increases the complexity of the
waveforms in the time domain. These waveforms also display a significant
sensitivity to initial conditions. For these reasons a standard matched-filter
search strategy is difficult. In contrast, the sharp and evenly spaced
resonance spectrum presents a much more robust signal to target. It persists
even in the absence of simple echoes. We also describe an additional
two-component structure of this resonance pattern.",1905.09370v3
2020-03-06,Resonant Very Low- and Ultra Low Frequency Digital Signal Reception Using a Portable Atomic Magnetometer,"Radio communication through attenuating media necessitates the use of
very-low frequency (VLF) and ultra-low frequency (ULF) carrier bands, which are
frequently used in underwater and under-ground communication applications.
Quantum sensing techniques can be used to circumvent hard constraints on the
size, weight and noise floor of classical signal transducers. In this
low-frequency range, an optically pumped atomic sample can be used to detect
carrier wave modulation resonant with ground-state Zeeman splitting of alkali
atoms. Using a compact, self-calibrating system we demonstrate a resonant
atomic transducer for digital data encoded using binary phase- and
frequency-keying of resonant carrier waves in the 200 Hz -200 kHz range. We
present field trial data showing sensor noise floor, decoded data and received
bit error rate, and calculate the projected range of sub-sea communication
using this device.",2003.03267v1
2020-11-24,Recoupling Mechanism for exotic mesons and baryons,"The infinite chain of transitions of one pair of mesons (channel I) into
another pair of mesons (channel II) can produce bound states and resonances in
both channels even if no interactions inside channels exist. These resonances
which can occur also in meson-baryon channels are called channel-coupling (CC)
resonances. A new mechanism of CC resonances is proposed where transitions
occur due to a rearrangement of confining strings inside each channel -- the
recoupling mechanism. The amplitude of this recoupling mechanism is expressed
via overlap integrals of the wave functions of participating mesons (baryons).
The explicit calculation with the known wave functions yields the peak at $E=
4.12$ GeV for the transitions $J/\psi + \phi \leftrightarrow D^*_s + \bar D^*_s
$, which can be associated with $\chi_{c1}(4140)$, and a narrow peak at $3.98$
GeV with the width $10$ MeV for the transitions $D^{-}_s + D^*_0
\leftrightarrow J/\psi + K^{*-},$ which can be associated with the recently
discovered $Z_{cs}(3985)$.",2011.12326v3
2016-11-16,On topology optimization of acoustic metamaterial lattices for locally resonant bandgaps of flexural waves,"Optimized topology of bi-material acoustic metamaterial lattice plates is
studied for maximized locally resonant bandgap of flexural guided waves.
Optimized layout of the two relatively stiff and compliant material phases in
the design domain is explored, free from any restrictions on the topology and
shape of the relevant domains. Multiobjective optimization is performed through
which maximized effective stiffness or minimized overall mass of the bandgap
topology is additionally ensured. Extreme and selected intermediate optimized
topologies of Pareto fronts are presented and their bandgap efficiencies and
effective stiffness are compared. The bi-material constitution of selected
topologies are further altered and modal band structure of resultant
multilateral and porous designs are evaluated. Novel, core-shell like, locally
resonant bandgaps are introduced. It is shown that how the bandgap efficiency
and structural mass and/or stiffness can be optimized through optimized
microstructural design of the matrix and the resonating core domains.",1611.06242v1
2019-01-27,Highly efficient cooling of mechanical resonator with square pulse drives,"Ground state cooling of mechanical resonator is a way to generate macroscopic
quantum states. Here we present a study of optomechanical cooling under the
drive of square pulses without smooth profile. By illustrating the dynamical
processes of cooling, we show how to choose the amplitudes and durations of
square pulses, as well as the intervals between them, so that a mechanical
resonator can be quickly cooled down to its ground state. Compared with the
cooling under a continuous-wave drive field, the ground state cooling of a
mechanical resonator can be performed more efficiently and flexibly by using
square pulse drives. At certain times of such cooling process, the thermal
phonon number under square pulse drives can become even lower than the
theoretical limit for the cooling with a continuous-wave drive field of the
same amplitude.",1901.09343v1
2019-04-15,Topologically protected bound states in the continuum and strong phase resonances in integrated Gires-Tournois interferometer,"Photonic bound states in the continuum (BICs) are eigenmodes with an infinite
lifetime, which coexist with a continuous spectrum of radiating waves. BICs are
not only of great theoretical interest, but have a wide range of practical
applications, e.g. in the design of optical resonators. Here, we study this
phenomenon in a new integrated nanophotonic element consisting of a single
dielectric ridge terminating an abruptly ended slab waveguide. This structure
can be considered as an on-chip analogue of the Gires-Tournois interferometer
(GTI). We demonstrate that, in contrast to the conventional GTI, the proposed
integrated structure supports high-Q phase resonances and ""conditional"" BICs.
We develop a simple but extremely accurate coupled-wave model, which clarifies
the physics of the BIC formation and enables predicting their locations. We
show that the studied BICs are topologically protected and, for the first time,
investigate the strong phase resonance effect, which occurs when two BICs with
opposite topological charges annihilate.",1904.06939v1
2019-04-22,Seismic wave shield using cubic arrays of split-ball resonators,"Metre size inertial resonators located in the ground have been theoretically
shown to interact with a seismic wave (attenuation, band gaps) to enable
protection of surface structures such as buildings. The challenge for Civil
Engineering is to both reduce the size of these resonators and to increase
their efficiency. Here we explore steel spheres, connected to a concrete bulk
medium, either by a coating of rubber, or rubber and steel ligaments, or air
and steel ligaments. We show that for a cubic lattice periodicity of 1 metre,
we achieve stop bands in the frequency range 14 to 20 Hz; by splitting spheres
in 2 and 8 pieces, we tune down the stop bands frequencies and further increase
their bandwidth. We thus demonstrate we are able to provide a variety of
inertial resonators with stop bands below 10 Hz i.e., in the frequency range of
interest for earthquake engineering.",1904.10767v1
2019-07-02,Distinguishing black holes from horizonless objects through the excitation of resonances during inspiral,"How well is the vacuum Kerr geometry a good description of the dark, compact
objects in our universe? Precision measurements of accreting matter in the deep
infrared and gravitational-wave measurements of coalescing objects are finally
providing answers to this question. Here, we study the possibility of resonant
excitation of the modes of the central object -- taken to be very compact but
horizonless -- during an extreme-mass-ratio inspiral. We show that for very
compact objects resonances are indeed excited. However, the impact of such
excitation on the phase of the gravitational-wave signal is negligible, since
resonances are crossed very quickly during inspiral.",1907.01561v4
2019-06-19,Generating and Detecting High Frequency Liquid-Based Sound Resonances with Nanoplasmonics,"We use metal nanostructures (nanoplasmonics) excited with dual frequency
lasers to generate and detect high frequency (> 10 GHz) sound wave resonances
in water. The difference frequency between the two lasers causes beating in the
intensity, which results in a drop in the transmission through the
nanostructure when an acoustic resonance is excited. By observing the resonance
frequency shifts with changing nanostructure size, the transition from slow to
fast sound in water is inferred, which has been measured by inelastic
scattering methods in the past. The observed behavior shows remarkable
similarities to a simple Debye model (without fitting parameters). The ability
to directly excite high-frequency sound waves in water may unlock the secret of
how the nanofluidic environment, that is typically considered to be extremely
viscous, can efficiently support the energetic dynamics of life via protein
vibrations at the nanometer scale.",1907.13230v1
2019-09-04,ARRAW: Anti-resonant reflecting acoustic waveguides,"Development of acoustic and optoacoustic on-chip technologies calls for new
solutions to guiding, storing and interfacing acoustic and optical waves in
integrated silicon-on-insulator (SOI) systems. One of the biggest challenges in
this field is to suppress the radiative dissipation of the propagating acoustic
waves, while co-localizing the optical and acoustic fields in the same region
of an integrated waveguide. Here we address this problem by introducing
Anti-Resonant Reflecting Acoustic Waveguides (ARRAWs) -- mechanical analogues
of the Anti-Resonant Reflecting Optical Waveguides (ARROWs). We discuss the
principles of anti-resonant guidance and establish guidelines for designing
efficient ARRAWs. Finally, we demonstrate examples of the simplest
silicon/silica ARRAW platforms that can simultaneously serve as near-IR optical
waveguides, and support strong backward Brillouin scattering.",1909.01632v2
2019-09-13,Hybrid Simulations of the Resonant and Non-Resonant Cosmic Ray Streaming Instability,"Using hybrid simulations (kinetic ions--fluid electrons), we test the linear
theory predictions of the cosmic ray (CR) streaming instability. We consider
two types of CR distribution functions: a ""hot"" distribution where CRs are
represented by a drifting power law in momentum and an anisotropic ""beam"" of
monochromatic particles. Additionally, for each CR distribution we scan over
different CR densities to transition from triggering the resonant to the
non-resonant (Bell) streaming instability. We determine the growth rates of
these instabilities in simulations by fitting an exponential curve during the
linear stage, and we show that they agree well with the theoretical predictions
as a function of wave number agree. We also examine the magnetic helicity as a
function of time and wave number, finding a general good agreement with the
predictions, as well as some unexpected non-linear features to the instability
development.",1909.06346v1
2019-10-17,"High frequency guided mode resonances in mass-loaded, thin film gallium nitride surface acoustic wave devices","We demonstrate high-frequency (> 3 GHz), high quality factor radio frequency
(RF) resonators in unreleased thin film gallium nitride (GaN) on sapphire and
silicon carbide substrates by exploiting acoustic guided mode (Lamb wave)
resonances. The associated energy trapping, due to mass loading from the gold
electrodes, allows us to efficiently excite these resonances from a 50 $\Omega$
input. The higher phase velocity, combined with lower electrode damping,
enables high quality factors with moderate electrode pitch, and provides a
viable route towards high-frequency piezoelectric devices. The GaN platform,
with its ability to guide and localize high-frequency sound on the surface of a
chip with access to high-performance active devices, will serve as a key
building block for monolithically integrated RF front-ends.",1910.08169v1
2019-12-12,Localized modes on a metasurface through multi-wave interactions,"In this paper, we describe the manifestation of localized states through
coherent and incoherent analyses of a diffuse elastic wavefield inside a
two-dimensional metamaterial made of a collection of vertical long beams glued
to a thin plate. We demonstrate that localized states arise due to multi-wave
interactions at the beam-plate attachment when the beams acts as coupled
resonators for both compressional and flexural resonances on the metasurface.
Due to the low-quality factor compressional resonance of the beams, inside the
main bandgap the modal density of the systel drops to near a high-quality
factor flexural resonance of the beams, and blocks the diffusion process of the
wavefield intensity. This experiment physically highlights the
tight-binding-like coupling in the localized regime for this two-dimensional
metamaterial.",1912.11530v1
2020-05-05,Sensitivity of resonance frequency in the detection of thin layer using nano-slit structures,"We derive the formulas for the resonance frequencies and their sensitivity
when the nano-slit structures are used in the detection of thin layers. For a
thin layer with a thickness of $H$ deposited over the nanostructure, we show
quantitatively that for both single and periodic slit structures with slit
aperture size $\delta$, the sensitivity of resonance frequency reduces as $H$
increases. Specifically, the sensitivity is of order $O(\delta/H)$ if $H
>\delta$ and of order $O(1+\ln H/\delta)$ otherwise. The evanescent wave modes
are present along the interface between the thin dielectric film and ambient
medium above. From the mathematical derivations, it is observed that the
sensitivity of the resonance frequency highly depends on the effect of
evanescent wave modes on the tiny slit apertures.",2005.03762v1
2020-09-30,Optimization under Uncertainty of a Chain of Nonlinear Resonators using a Field Representation,"Chains of resonators in the form of spring-mass systems have long been known
to exhibiting interesting properties such as band gaps. Such features can be
leveraged to manipulate the propagation of waves such as the filtering of
specific frequencies and, more generally, mitigate vibrations and impact.
Adding nonlinearities to the system can also provide further avenues to
manipulate the propagation of waves in the chain and enhance its performance.
This work proposes to optimally design such a chain of resonators to mitigate
vibrations in a robust manner by accounting for various sources of design
uncertainties (e.g., nonlinear stiffness) and aleatory uncertainties (e.g.,
loading). The stochastic optimization algorithm is tailored to account for
discontinuities in the chain response due to the presence of nonlinearities. In
addition, a field formulation is used to define the properties of the
resonators along the chain and reduce the dimensionality of the optimization
problem. It is shown that the combination of the stochastic optimization
algorithm and the field representation leads to robust designs that could not
be achieved with optimal properties constant over the chain.",2010.01198v1
2020-10-19,Controllable optical response and tunable sensing based on self interference in waveguide QED systems,"We study the self interference effect of a resonator coupled with a bent
waveguide at two separated ports. Such interference effects are shown to be
similar for the cases of standing-wave and traveling-wave resonators, while in
the system of two separated resonators indirectly coupled via a waveguide, the
coupling forms and the related interference effects depend on which kind of
resonators is chosen. Due to the self interference, controllable optical
responses including tunable linewidth and frequency shift, and optical dark
state can be achieved. Moreover, we consider a self-interference photon-magnon
hybrid model and show phase-dependent Fano-like line shapes which have
potential applications in frequency sensing. The photon-magnon hybridization
can not only enhance the sensitivity and provide tunable working region, but
also enables optical readout of the magnetic field strength in turn. The
results in this paper provide a deeper insight into the self interference
effect and its potential applications.",2010.09319v2
2020-12-20,The spurious resonance disease and how to cure it: application to the seismic response of a canyon,"Three types of boundary integral equation (BIE) methods are employed to
obtain closed-form solutions of a wave-scattering problem which are compared to
the exact, closed-form (reference), solution deriving from the
separation-of-variables technique. The problem involves either Dirichlet (D) or
Neumann (N) boundary conditions (BC) for a scatterer that is a circular
cylinder submitted to one or two incident waves. The three BIE methods lead to
different expressions for the traction (for D-BC) or boundary displacement (for
N-BC) by which numerous resonances are predicted whose frequency of occurrence
differs from one method to another. This is interpreted as being the sign that
the three methods are generally-defective and the resonances are 'spurious'.
This 'disease' is cured by combining two BIE into one in such a way that the
resulting BIE gives rise to a closed-form solution identical to the exact
reference solution devoid of spurious resonances.",2012.10989v1
2021-03-16,A non-local fluid closure for modeling cyclotron resonance in collisionless magnetized plasmas,"A fluid description for collisionless magnetized plasmas that takes into
account the effect of cyclotron resonance has been developed. Following the
same approach as the Landau fluid closure, the heat flux components associated
with transverse electromagnetic fluctuations are approximated by a linear
combination of lower-order moments in wavenumber space. The closure
successfully reproduces the linear cyclotron resonance for electromagnetic
waves propagating parallel to the ambient magnetic field. In the presence of
finite temperature anisotropy, the model gives approximately correct prediction
for an instability destabilized via the cyclotron resonance. A nonlinear
simulation demonstrates the wave growth consistent with the linear theory
followed by the reduction of initial anisotropy, and finally, the saturation of
the instability. The isotropization may be understood in terms of quasi-linear
theory, which is developed within the framework of the fluid model but very
similar to its fully kinetic counterpart. The result indicates that both linear
and nonlinear collisionless plasma responses are approximately incorporated in
the fluid model.",2103.08880v1
2022-05-29,Wave scattering by objects made of small particles with oscillating permittivity,"Rapid advancements in the micro and nano-technology create unlimited
opportunities for design of novel optical materials and their applications.
Recently, the possibility of the fast refractive index modulation was
demonstrated in semiconductors. In this paper we study the wave scattering by
small dispersionless particles with periodically varying refractive index in
scalar case by using the local perturbation method. The used formalism allows
us to study theoretically and numerically the scattering by objects made of
small particles of arbitrary shape and with oscillating refractive index.
  In this work, the field scattered by the cluster of the particles and its
resonance frequencies are calculated theoretically. In addition, the results of
the numerical modeling of the scattering by single cube and by cluster of cubes
with oscillating permittivity are presented. It was shown that the scattered
fields and their resonance frequencies are significantly affected by the
oscillating permittivity: existing resonances are shifting, new scattering
resonances are emerging, and deeps in the scattering spectrum are appearing.",2205.14702v2
2022-09-14,Macroscopic quantum test with bulk acoustic wave resonators,"Recently, solid-state mechanical resonators have become a platform for
demonstrating non-classical behavior of systems involving a truly macroscopic
number of particles. Here, we perform the most macroscopic quantum test in a
mechanical resonator to date, which probes the validity of quantum mechanics at
the microgram mass scale. This is done by a direct measurement of the Wigner
function of a high-overtone bulk acoustic wave resonator mode, monitoring the
gradual decay of negativities over tens of microseconds. While the obtained
macroscopicity of $\mu= 11.3$ is on par with state-of-the-art atom
interferometers, future improvements of mode geometry and coherence times could
confirm the quantum superposition principle at unprecedented scales.",2209.06635v2
2022-10-10,"Canonical Four-Wave-Mixing in Photonic Crystal Resonators: tuning, tolerances and scaling","Canonical Four-Wave-Mixing occurs in a resonator with only the required
number of modes, thereby inhibiting competing parametric processes. The
properties of the recently introduced photonic crystal parametric oscillator,
Marty et al. Nat. Photonics, 15, 53 (2021), are discussed extensively. We
compare the bichromatic design with other geometries of photonic crystal
resonators. Based on a statistical study over more than 100 resonators and 10
parametric oscillators, robustness against fabrication tolerances is assessed,
performances are evaluated in terms of average values and their dispersion, and
the dependence on the main parameters is shown to follow the theoretical
scaling. The lowest pump power at threshold is $\approx$ 40 $\mu$W and we show
the existence of a minimum value of the cavity photon lifetime as a condition
for parametric oscillation, which is related to three photon absorption.",2210.04660v1
2022-11-03,"Extremely Narrow, Sharp-Peaked Resonances at the Edge of the Continuum","We report a critical narrowing of resonances of a driven potential well, when
their eigenfrequencies approach the edge of the continuum. The resonances also
obtain unusual sharp-peak shapes at the continuum boundary. The situation can
be realized for the electromagnetic wave propagating across the dielectric thin
films with a periodically modulated interface(s). We show the general
phenomenon semi-analytically on a simplified model of a driven quantum
potential well, also by rigorous numerical analysis of Maxwell equations for
the wave propagation across the thin film with a modulated interface(s). We
justify the phenomenon experimentally, by the measurements of light reflection
from the dielectric thin film deposited on a periodically modulated surface.
The narrow and sharp-peak resonances can be used for an efficient narrow-band
frequency- and spatial filtering of light.",2211.01997v1
2022-11-29,Shape resonances in photoionization cross sections and time delay,"Shape resonances in photoionization of atoms and molecules arise from a
particular geometry of the ionic potential which traps the receding
photoelectron in a quasi-bound state in a particular partial wave. This
mechanism allows us to connect the photoionization cross section in the
resonant region with the photoelectron scattering phase in this partial wave by
a simple formula $\sigma \propto \sin^2\delta_\ell$. Due to this relation, the
phase $\delta_\ell$ can be extracted from an experimentally known cross section
and then converted to the photoelectron group delay (Wigner time delay)
$\tau_{\rm W} = \partial \delta_\ell/\partial E$ which is measurable by
recently developed laser interferometric techniques. Such a direct connection
of the photoionization cross section and the time delay is a fundamental
property of shape resonances which provides a comprehensive test of novel
measurements against a large body of older synchrotron data.",2211.15892v1
2022-12-01,Polarization-Tuned Fano Resonances in All-Dielectric Short-Wave Infrared Metasurface,"The short-wave infrared (SWIR) is an underexploited portion of the
electromagnetic spectrum in metasurface-based nanophotonics despite its
strategic importance in sensing and imaging applications. This is mainly
attributed to the lack of material systems to tailor light-matter interactions
in this range. Herein, we address this limitation and demonstrate an
all-dielectric silicon-integrated metasurface enabling polarization-induced
Fano resonance control at SWIR frequencies. The platform consists of a
two-dimensional Si/GeSn core/shell nanowire array on a silicon wafer. By tuning
the light polarization, we show that the metasurface reflectance can be
efficiently engineered due to Fano resonances emerging from the electric and
magnetic dipoles competition. The interference of optically induced dipoles in
high-index nanowire arrays offers additional degrees of freedom to tailor the
directional scattering and the flow of light while enabling sharp
polarization-modulated resonances. This tunability is harnessed in nanosensors
yielding an efficient detection of 10^{-2} changes in the refractive index of
the surrounding medium.",2212.00758v1
2023-03-15,Observation of Electronic Modes in Open Cavity Resonator,"The resemblance between electrons and optical waves has strongly driven the
advancement of mesoscopic physics. However, electron waves have yet to be
understood in open cavity structures which have provided contemporary optics
with rich insight towards non-Hermitian systems and complex interactions
between resonance mode. Here, we report the realization of an open cavity
resonator in a two-dimensional electronic system. We studied the resonant
electron modes within the cavity and resolved the signatures of longitudinal
and transverse quantization, showing that the modes are robust despite the
openness of the cavity being highly open to the background continuum. The
transverse modes were investigated by applying a controlled deformation to the
cavity, and their spatial distributions were further analyzed using
magnetoconductance measurements and numerical simulation. These results lay the
groundwork to exploring electronic wavefunctions in the context of modern
optical systems, such as the dielectric microcavity.",2303.08386v1
2023-04-12,Multi-bounce resonances in the interaction of walking droplets,"Discrete dynamical models of walking droplets (""walkers"") have allowed swift
numerical experiments revealing heretofore unobserved quantum statistics and
related behaviors in a classical hydrodynamic system. We present evidence that
one such model of walking droplets exhibits the empirically elusive $n$-bounce
resonances that are traditionally seen in the scattering of solitary waves
governed by covariant nonlinear field theories with polynomial
self-interaction. A numerical investigation of the chosen model of interacting
walking droplets reveals a fractal structure of resonances in the velocity
in--velocity out diagram, much like the usual maps constructed for collisions
of solitary waves. We suggest avenues for further theoretical analysis of
walker collisions, which may connect this discrete model to the field-theoretic
setting, as well as directions towards new experimental realizations $n$-bounce
resonances.",2304.06001v2
2023-06-09,Resonances and scattering in microscopic cluster models with the complex-scaled generator coordinate method,"The generator coordinate method of a microscopic cluster model is developed
to treat the resonance and scattering of nuclear clusters with complex scaling.
We consistently derive the formulation of the complex scaling for the
microscopic cluster model, in which only the relative motions between clusters
are transformed in the generator coordinate wave function. We also reveal the
applicability of this method to the cluster wave function. Furthermore, we
demonstrate this framework in the 2$\alpha$ system of $^8$Be and obtain the
solutions of resonance and non-resonant continuum states. Using these
solutions, we calculate the level density, which brings the phase shifts of the
cluster-cluster scattering. This work becomes the foundation in the description
of the multi-cluster scattering states of nuclei in a microscopic framework
with complex scaling.",2306.05660v2
2023-06-26,Shaping Exciton Dynamics in 2D Semiconductors by Tailored Ultrafast Pulses,"Excitonic resonances in two-dimensional semiconductors play a crucial role in
enhancing nonlinear light-matter interactions. However, the influence of
resonant dynamics on the time-dependent behavior of these nonlinear effects has
received little attention, as optical wave-mixing is commonly assumed to be
instantaneous. In this study, we investigate the impact of excited state
dynamics on the generation of second and third-order nonlinearities from
Monolayer $\text{WSe}_\text{2}$ in ambient conditions. By shaping a sub-10fs
driving pulse to complement the exciton resonant dynamics, we demonstrate a
significant enhancement of four-wave-mixing beyond what is achieved using a
transform-limited pulse. Conversely, a time-reversed pulse shape leads to
destructive quantum interference effects, suppressing nonlinear generation. We
apply this technique simultaneously to two successive exciton states,
showcasing the selective choice in the resonant state that produces
nonlinearity. The ability to control nonlinear carrier dynamics in
two-dimensional semiconductors holds promise for remote noninvasive optical
manipulation in optoelectronic devices.",2306.15005v1
2023-07-11,Dispersive estimates for 1D matrix Schrödinger operators with threshold resonance,"We establish dispersive estimates and local decay estimates for the time
evolution of non-self-adjoint matrix Schr\""odinger operators with threshold
resonances in one space dimension. In particular, we show that the decay rates
in the weighted setting are the same as in the regular case after subtracting a
finite rank operator corresponding to the threshold resonances. Such matrix
Schr\""odinger operators naturally arise from linearizing a focusing nonlinear
Schr\""odinger equation around a solitary wave. It is known that the linearized
operator for the 1D focusing cubic NLS equation exhibits a threshold resonance.
We also include an observation of a favorable structure in the quadratic
nonlinearity of the evolution equation for perturbations of solitary waves of
the 1D focusing cubic NLS equation.",2307.04943v2
2023-07-18,Low-Temperature Characteristics of an AlN/Diamond Surface Acoustic Wave Resonator,"Phonons confined in mechanical resonators can be coupled to a variety of
quantum systems and are expected to be applied to hybrid quantum systems.
Diamond surface acoustic wave (SAW) devices are capable of high efficiency in
phonon interaction with color centers in diamond. The temperature dependence of
the quality factor is crucial for inferring the governing mechanism of coupling
efficiency between phonons and color centers in diamond. In this paper, we
report on the temperature dependence of the quality factor of an AlN/diamond
SAW device from room temperature to 5 K. The temperature dependence of the
quality factor and resonant frequency suggests that the mechanism of SAW
dissipation in the AlN/diamond SAW resonator at 5 GHz is the phonon-phonon
scattering in the Akheiser region, and that further cooling can be expected to
improve the quality factor. This result provides a crucial guideline for the
future design of AlN/diamond SAW devices.",2307.10271v1
2023-10-12,Half-Wave Dipolar Metal-Semiconductor Laser,"Nano-scale lasers harnessing metallic plasmons hold promise across physical
sciences and industrial applications. Plasmons are categorized as surface
plasmon polaritons (SPP) and localized surface plasmons (LSP). While SPP has
gained popularity for nano-lasers by fitting a few cycles of SPP waves into
resonators, achieving LSP lasing in single nanoparticles remains an elusive
goal. Here, we highlight the equivalence of LSP and SPP within resonant systems
and present lasers oscillating in the lowest-order LSP or, equivalently,
half-cycle SPP. This diffraction-limited dipolar emitter is realized through
strong coupling of plasmonic oscillation in gold and dielectric resonance in
high-gain III-V semiconductor in the near infrared away from surface plasmon
frequencies. The resulting single-mode stimulated emission peak exhibits
linewidth Q factors over 50 at room temperature, with wide tunability spanning
from 1190 to 1460 nm determined by resonator sizes ranging from 190 to 280 nm.
A semiconductor laser model elucidates the temporal and spectral buildup
dynamics under optical pumping. Notably, linewidth Q values surpassing 250 are
attained from higher-order, isolated laser particles within live biological
cells. These results offer fresh perspectives in nanophotonics and indicate
promising opportunities for multiplexed biological applications.",2310.08742v1
2023-11-15,Near 6 GHz Sezawa Mode Surface Acoustic Wave Resonators using AlScN on SiC,"Surface Acoustic Wave (SAW) devices featuring Aluminum Scandium Nitride
(AlScN) on a 4H-Silicon Carbide (SiC) substrate, offer a unique blend of high
sound velocity, low thermal resistance, substantial piezoelectric response,
simplified fabrication, as well as suitability for high-temperature and harsh
environment operation. This study presents high-frequency SAW resonators
employing AlScN thin films on SiC substrates, utilizing the second SAW mode
(referred to as the Sezawa mode). The resonators achieve remarkable
performance, boasting a K2 value of 5.5% and a maximum Q-factor (Qmax) of 1048
at 4.7 GHz, outperforming previous benchmarks. Additionally, a SAW resonator
with a 960 nm wavelength attains 5.9 GHz frequency with record K2 (4.0%) and
Qmax (887). Our study underscores the potential of the AlScN on SiC platform
for advanced radio-frequency applications.",2311.08694v1
2023-12-15,Exponentially localised interface eigenmodes in finite chains of resonators,"This paper studies wave localisation in chains of finitely many resonators.
There is an extensive theory predicting the existence of localised modes
induced by defects in infinitely periodic systems. This work extends these
principles to finite-sized systems. We consider finite systems of subwavelength
resonators arranged in dimers that have a geometric defect in the structure.
This is a classical wave analogue of the Su-Schrieffer-Heeger model. We prove
the existence of a spectral gap for defectless finite dimer structures and find
a direct relationship between eigenvalues being within the spectral gap and the
localisation of their associated eigenmode. Then we show the existence and
uniqueness of an eigenvalue in the gap in the defect structure, proving the
existence of a unique localised interface mode. To the best of our knowledge,
our method, based on Chebyshev polynomials, is the first to characterise
quantitatively the localised interface modes in systems of finitely many
resonators.",2312.09667v2
2023-12-30,Harnessing vibrational resonance to identify and enhance input signals,"We report the occurrence of vibrational resonance (VR) and the underlying
mechanism in a simple piecewise linear electronic circuit, namely the
Murali-Lakshmanan-Chua (MLC) circuit, driven by an additional biharmonic signal
with widely different frequency. When the amplitude of the high-frequency force
is tuned, the resultant vibrational resonance is used to detect the
low-frequency signal and also to enhance it into a high-frequency signal.
Further, we also show that even when the low-frequency signal is changed from
sine wave to square and sawtooth waves, vibrational resonance can be used to
detect and enhance them into high-frequency signals. These behaviors, confirmed
by experimental results, are illustrated with appropriate analytical and
numerical solutions of the corresponding circuit equations describing the
system. Finally, we also verify the signal detection in the above circuit even
with the addition of noise.",2401.00150v1
2024-03-14,Experimental Study of Periodically Poled Piezoelectric Film Lithium Niobate Resonator at Cryogenic Temperatures,"This work reports the first study of periodically poled piezoelectric film
(P3F) lithium niobate (LiNbO3) resonators at cryogenic temperatures. We
experimentally investigate the temperature dependency of resonant frequencies
and quality factor (Q) of higher-order Lamb modes up to 20 GHz between
80{\deg}K and 297{\deg}K, using a tri-layer P3F LiNbO3 resonators as the
experimental platform. The supported thickness-shear Lamb modes between
second-order symmetric (S2) and eleventh-order antisymmetric (A11) modes show
temperature coefficients of frequency (TCF) averaging -68.8 ppm/K. Higher Q and
more pronounced spurious modes are observed at lower temperatures for many
modes. Upon further study, the cryogenic study will be crucial for identifying
dominant loss mechanisms and origins of spurious modes in higher-order Lamb
wave devices for millimeter-wave applications.",2403.09822v1
2002-07-26,Spin injection and spin accumulation in all-metal mesoscopic spin valves,"We study the electrical injection and detection of spin accumulation in
lateral ferromagnetic metal-nonmagnetic metal-ferromagnetic metal (F/N/F) spin
valve devices with transparent interfaces. Different ferromagnetic metals,
permalloy (Py), cobalt (Co) and nickel (Ni), are used as electrical spin
injectors and detectors. For the nonmagnetic metal both aluminium (Al) and
copper (Cu) are used. Our multi-terminal geometry allows us to experimentally
separate the spin valve effect from other magneto resistance signals such as
the anomalous magneto resistance (AMR) and Hall effects. We find that the AMR
contribution of the ferromagnetic contacts can dominate the amplitude of the
spin valve effect, making it impossible to observe the spin valve effect in a
'conventional' measurement geometry. In a 'non local' spin valve measurement we
are able to completely isolate the spin valve signal and observe clear spin
accumulation signals at T=4.2 K as well as at room temperature (RT). For
aluminum we obtain spin relaxation lengths (lambda_{sf}) of 1.2 mu m and 600 nm
at T=4.2 K and RT respectively, whereas for copper we obtain 1.0 mu m and 350
nm. The spin relaxation times tau_{sf} in Al and Cu are compared with theory
and results obtained from giant magneto resistance (GMR), conduction electron
spin resonance (CESR), anti-weak localization and superconducting tunneling
experiments. The spin valve signals generated by the Py electrodes (alpha_F
lambda_F=0.5 [1.2] nm at RT [T=4.2 K]) are larger than the Co electrodes
(alpha_F lambda_F=0.3 [0.7] nm at RT [T=4.2 K]), whereas for Ni (alpha_F
lambda_F<0.3 nm at RT and T=4.2 K) no spin signal is observed. These values are
compared to the results obtained from GMR experiments.",0207641v1
2018-10-31,Transverse Magneto-Optical Kerr Effect at Narrow Optical Resonances,"Magneto-optical spectroscopy based on the transverse magneto-optical Kerr
effect (TMOKE) is a sensitive method for investigation of magnetically-ordered
media. However, in magnetic materials the optical transitions are usually
characterized by spectrally broad resonances with widths considerably exceeding
the Zeeman splitting in the magnetic field. Here we investigate experimentally
and theoretically the TMOKE in the vicinity of relatively narrow optical
resonances provided by confined quantum systems. For experimental demonstration
we use the exciton resonance in a (Cd,Mn)Te diluted magnetic semiconductor
quantum well, where the strong exchange interaction with magnetic ions enables
the giant Zeeman splitting of exciton spin states $\Delta$ in magnetic fields
of a few Tesla. In the weak coupling regime, when the splitting $\Delta$ is
smaller than the spectral broadening of the optical transitions $\Gamma$, the
TMOKE magnitude grows linearly with the increase of the Zeeman splitting and
its spectrum has an S-shape, which remains virtually unchanged in this range.
In the strong coupling regime ($\Delta>\Gamma$) the TMOKE magnitude saturates,
while its spectrum is strongly modified resulting in the appearance of two
separate peaks. The TMOKE is sensitive not only to the sample surface but can
be used to probe the confined electronic states in depth if the upper layer is
sufficiently transparent. Our results demonstrate that TMOKE of spectrally
narrow resonances serves as a versatile tool for probing the charge and spin
structure of electronic states in various confined quantum systems and can be
used for spin tomography in combination with the conventional polar Kerr
effect.",1810.13344v1
2019-06-14,Engineering electron-phonon coupling of quantum defects to a semi-confocal acoustic resonator,"Diamond-based microelectromechanical systems (MEMS) enable direct coupling
between the quantum states of nitrogen-vacancy (NV) centers and the phonon
modes of a mechanical resonator. One example, diamond high-overtone bulk
acoustic resonators (HBARs), feature an integrated piezoelectric transducer and
support high-quality factor resonance modes into the GHz frequency range. The
acoustic modes allow mechanical manipulation of deeply embedded NV centers with
long spin and orbital coherence times. Unfortunately, the spin-phonon coupling
rate is limited by the large resonator size, $>100~\mu$m, and thus
strongly-coupled NV electron-phonon interactions remain out of reach in current
diamond BAR devices. Here, we report the design and fabrication of a
semi-confocal HBAR (SCHBAR) device on diamond (silicon carbide) with $f\cdot
Q>10^{12}$($>10^{13}$). The semi-confocal geometry confines the phonon mode
laterally below 10~$\mu$m. This drastic reduction in modal volume enhances
defect center electron-phonon coupling. For the native NV centers inside the
diamond device, we demonstrate mechanically driven spin transitions and show a
high strain-driving efficiency with a Rabi frequency of
$(2\pi)2.19(14)$~MHz/V$_{p}$, which is comparable to a typical microwave
antenna at the same microwave power.",1906.06309v1
2017-06-08,Holographic description of $SO(5) \rightarrow SO(4)$ composite Higgs model,"We study a 5D bottom-up holographic model that is expected to describe the
dynamics of the minimal composite Higgs model characterized by a $SO(5)\to
SO(4)$ global symmetry breaking pattern. We assume that the fundamental degrees
of freedom are scalars transforming under some representation of $SO(5)$ and
subject to some unspecified strong interactions. The holographic description
presented here is inspired by previous studies performed in the context of QCD
and it allows for the consideration of spin one and spin zero resonances. The
resulting spectrum leads in a natural way to a variety of resonances. Namely,
those transforming under the unbroken $SO(4)$ subgroup exhibit an exact
degeneracy between the two Regge trajectories of vector and scalar channels,
while the resonances with quantum numbers in the $SO(5)/ SO(4)$ coset lie on a
trajectory of (heavier) spin one states and a non-degenerated one of scalar
resonances where the four lowest lying ones are massless. These correspond to
the four Goldstone bosons in 4D associated to the global symmetry breaking
pattern. Restrictions derived from the experimental constraints (Higgs
couplings, $S$ parameter, etc.) are then implemented and we conclude that the
model is able to accommodate vector and scalar resonances with masses in the
range 1 TeV to 2 TeV without encountering phenomenological difficulties.
Extension to generic models characterized by the breaking pattern $SO(N)\to
SO(N^\prime<N)$ is straightforward.",1706.02651v2
2021-06-04,Resonant optical topological Hall conductivity from skyrmions,"We study the high frequency Hall conductivity in a two-dimensional (2D) model
of conduction electrons coupled to a background magnetic skyrmion texture via
an effective Hund's coupling term. For an ordered skyrmion crystal, a Kubo
formula calculation using the basis of skyrmion crystal Chern bands reveals a
resonant Hall response at a frequency set by the Hund's coupling:
$\hbar\omega_{\text{res}} \approx J_H$. A complementary real-space Kubo formula
calculation for an isolated skyrmion in a box reveals a similar resonant Hall
response. A linear relation between the area under the Hall resonant curve and
the skyrmion density is discovered numerically and is further elucidated using
a gradient expansion which is valid for smooth textures and a local
approximation based on a spin-trimer calculation. We point out the issue of
distinguishing this skyrmion contribution from a similar feature arising from
spin-orbit interactions, as demonstrated in a model for Rashba spin-orbit
coupled electrons in a collinear ferromagnet, which is analogous to the
difficulty of unambiguously separating the d.c. topological Hall effect from
the anomalous Hall effect. The resonant feature in the high frequency
topological Hall effect is proposed to provide a potentially useful local
optical signature of skyrmions via probes such as scanning magneto-optical Kerr
microscopy.",2106.02641v2
2024-03-02,Strangeness plus-one ($S=+1$) resonance-state $P^{+*}_0$ via $K^+n\to K^{*0}p$,"In our current study, we delve into the peak-like structure observed during
the reaction process of $K^+n\to K^{0}p$ at approximately $\sqrt{s}\sim2.5$
GeV. Our focus centers on exploring the potential $S=+1$ resonance
$P^{+*}_0\equiv P^*_0$ as an excited state within the extended vector-meson and
baryon ($VB$) antidecuplet. To achieve this aim, we employ the effective
Lagrangian method in conjunction with the $(u,t)$-channel Regge approach,
operating within the tree-level Born approximation. We thoroughly examine
various spin-parity quantum numbers for the resonance, resulting in a
compelling description of the data, where $M_{P^*_0}\approx2.5$ GeV and
$\Gamma_{P^*_0}\approx100$ MeV. Furthermore, we propose an experimental
technique to amplify the signal-to-noise ratio ($S/N$) for accurately measuring
the resonance. Notably, our findings reveal that background interference
diminishes significantly within the $K^*$ forward-scattering region in the
center-of-mass frame when the $K^*$ is perpendicularly polarized to the
reaction plane. Additionally, we explore the recoil-proton spin asymmetry to
definitively determine the spin and parity of the resonance. This study stands
to serve as a valuable reference for designing experimental setups aimed at
investigating and comprehending exotic phenomena in QCD. Specifically, our
insights will inform future J-PARC experiments, particularly those employing
higher kaon beam energies.",2403.01191v1
2007-10-15,High-Efficiency Resonant RF Spin Rotator with Broad Phase Space Acceptance for Pulsed Polarized Cold Neutron Beams,"We have developed a radio-frequency resonant spin rotator to reverse the
neutron polarization in a 9.5 cm x 9.5 cm pulsed cold neutron beam with high
efficiency over a broad cold neutron energy range. The effect of the spin
reversal by the rotator on the neutron beam phase space is compared
qualitatively to RF neutron spin flippers based on adiabatic fast passage. The
spin rotator does not change the kinetic energy of the neutrons and leaves the
neutron beam phase space unchanged to high precision. We discuss the design of
the spin rotator and describe two types of transmission-based neutron spin-flip
efficiency measurements where the neutron beam was both polarized and analyzed
by optically-polarized 3He neutron spin filters. The efficiency of the spin
rotator was measured to be 98.0+/-0.8% on resonance for neutron energies from
3.3 to 18.4 meV over the full phase space of the beam. As an example of the
application of this device to an experiment we describe the integration of the
RF spin rotator into an apparatus to search for the small parity-violating
asymmetry A_gamma in polarized cold neutron capture on para-hydrogen by the
NPDGamma collaboration at LANSCE.",0710.2871v1
2015-08-25,Controlling spin relaxation with a cavity,"Spontaneous emission of radiation is one of the fundamental mechanisms by
which an excited quantum system returns to equilibrium. For spins, however,
spontaneous emission is generally negligible compared to other non-radiative
relaxation processes because of the weak coupling between the magnetic dipole
and the electromagnetic field. In 1946, Purcell realized that the spontaneous
emission rate can be strongly enhanced by placing the quantum system in a
resonant cavity -an effect which has since been used extensively to control the
lifetime of atoms and semiconducting heterostructures coupled to microwave or
optical cavities, underpinning single-photon sources. Here we report the first
application of these ideas to spins in solids. By coupling donor spins in
silicon to a superconducting microwave cavity of high quality factor and small
mode volume, we reach for the first time the regime where spontaneous emission
constitutes the dominant spin relaxation mechanism. The relaxation rate is
increased by three orders of magnitude when the spins are tuned to the cavity
resonance, showing that energy relaxation can be engineered and controlled
on-demand. Our results provide a novel and general way to initialise spin
systems into their ground state, with applications in magnetic resonance and
quantum information processing. They also demonstrate that, contrary to popular
belief, the coupling between the magnetic dipole of a spin and the
electromagnetic field can be enhanced up to the point where quantum
fluctuations have a dramatic effect on the spin dynamics; as such our work
represents an important step towards the coherent magnetic coupling of
individual spins to microwave photons.",1508.06148v2
2019-09-26,"Perdeuteration of poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (d-MEHPPV): control of microscopic charge-carrier spin-spin coupling and of magnetic-field effects in optoelectronic devices","Control of the effective local hyperfine fields in a conjugated polymer,
poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEHPPV), by
isotopic engineering is reported. These fields, evident as a
frequency-independent line broadening mechanism in electrically detected
magnetic resonance spectroscopy (EDMR), originate from the unresolved hyperfine
coupling between the electronic spin of charge carrier pairs and the nuclear
spins of surrounding hydrogen isotopes. The room temperature study of effects
caused by complete deuteration of this polymer through magnetoresistance,
magnetoelectroluminescence, coherent pulsed and multi-frequency EDMR, as well
as inverse spin-Hall effect measurements, confirm the weak hyperfine broadening
of charge carrier magnetic resonance lines. As a consequence, we can resolve
coherent charge-carrier spin-beating, allowing for direct measurements of the
magnitude of electronic spin-spin interactions. In addition, the weak hyperfine
coupling allows us to resolve substantial spin-orbit coupling effects in EDMR
spectra, even at low magnetic field strengths. These results illustrate the
dramatic influence of hyperfine fields on the spin physics of organic
light-emitting diode (OLED) materials at room temperature, and point to routes
to reaching exotic ultra-strong resonant-drive regimes needed for the study of
light-matter interactions.",1909.12213v1
2023-10-22,Non-Bloch-Siegert-type power-induced shift of two-photon electron paramagnetic resonances of charge-carrier spin states in an OLED,"We present Floquet theory-based predictions and electrically detected
magnetic resonance (EDMR) experiments scrutinizing the nature of two-photon
magnetic resonance shifts of charge-carrier spin states in the perdeuterated
$\pi$-conjugated polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene
vinylene] (d-MEH-PPV) under strong magnetic resonant drive conditions
(radiation amplitude $B_1$ ~ Zeeman field $B_0$). Numerical calculations show
that the two-photon resonance shift with power is nearly drive-helicity
independent. This is in contrast to the one-photon Bloch-Siegert shift that
only occurs under non-circularly polarized strong drive conditions. We
therefore treated the Floquet Hamiltonian analytically under arbitrary
amplitudes of the co- and counter-rotating components of the radiation field to
gain insight into the nature of the helicity dependence of multi-photon
resonance shifts. In addition, we tested Floquet-theory predictions
experimentally by comparing one-photon and two-photon charge-carrier spin
resonance shifts observed through room-temperature EDMR experiments on
d-MEH-PPV-based bipolar injection devices [i.e., organic light emitting diode
structures (OLEDs)]. We found that under the experimental conditions of strong,
linearly polarized drive, our observations consistently agree with theory,
irrespective of the magnitude of $B_1$, and therefore underscore the robustness
of Floquet theory in predicting nonlinear magnetic resonance behaviors.",2310.14180v1
2009-12-17,An improved effective-one-body Hamiltonian for spinning black-hole binaries,"Building on a recent paper in which we computed the canonical Hamiltonian of
a spinning test particle in curved spacetime, at linear order in the particle's
spin, we work out an improved effective-one-body (EOB) Hamiltonian for spinning
black-hole binaries. As in previous descriptions, we endow the effective
particle not only with a mass m, but also with a spin S*. Thus, the effective
particle interacts with the effective Kerr background (having spin S_Kerr)
through a geodesic-type interaction and an additional spin-dependent
interaction proportional to S*. When expanded in post-Newtonian (PN) orders,
the EOB Hamiltonian reproduces the leading order spin-spin coupling and the
spin-orbit coupling through 2.5PN order, for any mass-ratio. Also, it
reproduces all spin-orbit couplings in the test-particle limit. Similarly to
the test-particle limit case, when we restrict the EOB dynamics to spins
aligned or antialigned with the orbital angular momentum, for which circular
orbits exist, the EOB dynamics has several interesting features, such as the
existence of an innermost stable circular orbit, a photon circular orbit, and a
maximum in the orbital frequency during the plunge subsequent to the inspiral.
These properties are crucial for reproducing the dynamics and
gravitational-wave emission of spinning black-hole binaries, as calculated in
numerical relativity simulations.",0912.3517v2
2012-07-12,Anomalous and spin Hall effects in hcp cobalt from GGA + U calculations,"We have calculated the intrinsic anomalous and spin Hall conductivities, spin
and orbital magnetic moments and also spin polarization of Hall currentsin
hexagonal cobalt within the density functional theory with the generalized
gradient approximation (GGA) plus on-site Coulomb interaction (GGA+$U$). The
accurate all-electron full-potential linearized augmented plane wave method is
used. We find that the anomalous Hall conductivity (AHC) ($\sigma_{xy}^A$) and
orbital magnetic moment ($m_o$) of cobalt with the magnetization being along
the c-axis ($m//c$) calculated in the GGA+$U$ scheme with $U = 1.6$ eV and $J =
0.9$ eV agree rather well with the corresponding experimental values while, in
contrast, the $\sigma_{xy}^A$ and $m_o$ from the GGA calculations are
significantly smaller than the measured ones. This suggests that moderate $U =
1.6$ eV and $J = 0.9$ eV are appropriate for Co metals. The calculated AHC and
spin Hall conductivity (SHC) ($\sigma^S$) are highly anisotropic, and the ratio
of the Hall conductivity for $m//c$ to that for the magnetization being
in-plane ($m//ab$) from the GGA+$U$ calculations, is $\sim$16.0 for the AHC and
$\sim$6.0 for the SHC. For $m//c$, the spin-up and spin-down Hall currents are
found to flow in the same direction. The magnitude of the calculated Hall
current spin polarization ($P^H$) is large and $P^H = -0.61$. Remarkably, for
$m//ab$, the spin-up and spin-down Hall currents are predicted to flow in the
opposite directions. This indicates that the Hall current contains both
spin-polarized charge current and pure spin current, resulting in the magnitude
of the Hall current spin polarization ($P^H = -1.59$) being larger than 1.0.",1207.2876v1
2021-08-29,Nuclear spin-wave quantum register for a solid state qubit,"Solid-state nuclear spins surrounding individual, optically addressable
qubits provide a crucial resource for quantum networks, computation and
simulation. While hosts with sparse nuclear spin baths are typically chosen to
mitigate qubit decoherence, developing coherent quantum systems in nuclear
spin-rich hosts enables exploration of a much broader range of materials for
quantum information applications. The collective modes of these dense nuclear
spin ensembles provide a natural basis for quantum storage, however, utilizing
them as a resource for single spin qubits has thus far remained elusive. Here,
by using a highly coherent, optically addressed 171Yb3+ qubit doped into a
nuclear spin-rich yttrium orthovanadate crystal, we develop a robust quantum
control protocol to manipulate the multi-level nuclear spin states of
neighbouring 51V5+ lattice ions. Via a dynamically-engineered spin exchange
interaction, we polarise this nuclear spin ensemble, generate collective spin
excitations, and subsequently use them to implement a long-lived quantum
memory. We additionally demonstrate preparation and measurement of maximally
entangled 171Yb--51V Bell states. Unlike conventional, disordered nuclear spin
based quantum memories, our platform is deterministic and reproducible,
ensuring identical quantum registers for all 171Yb qubits. Our approach
provides a framework for utilising the complex structure of dense nuclear spin
baths, paving the way for building large-scale quantum networks using single
rare-earth ion qubits.",2108.12723v1
2020-10-12,Generic Field-Driven Phenomena in Kitaev Spin Liquids: Canted Magnetism and Proximate Spin Liquid Physics,"Topological spin liquids in two spatial dimensions are stable phases in the
presence of a small magnetic field, but may give way to field-induced phenomena
at intermediate field strengths. Sandwiched between the low-field spin liquid
physics and the high-field spin-polarized phase, the exploration of magnetic
phenomena in this intermediate regime however often remains elusive to
controlled analytical approaches. Here we numerically study such
intermediate-field magnetic phenomena for two representative Kitaev models (on
the square-octagon and decorated honeycomb lattice) that exhibit either Abelian
or non-Abelian topological order in the low-field limit. Using a combination of
exact diagonalization and density matrix renormalization group techniques, as
well as linear spin-wave theory, we establish the generic features of Kitaev
spin liquids in an external magnetic field. While ferromagnetic models
typically exhibit a direct transition to the polarized state at a relatively
low field strength, antiferromagnetic couplings not only substantially
stabilizes the topological spin liquid phase, but generically lead to the
emergence of a distinct field-induced intermediate regime, separated by a
crossover from the high-field polarized regime. Our results suggest that, for
most lattice geometries, this regime generically exhibits significant spin
canting, antiferromagnetic spin-spin correlations, and an extended proximate
spin liquid regime at finite temperatures. Notably, we identify a symmetry
obstruction in the original honeycomb Kitaev model that prevents, at least for
certain field directions, the formation of such canted magnetism without
breaking symmetries -- consistent with the recent numerical observation of an
extended gapless spin liquid in this case.",2010.05921v1
2022-01-05,Equatorial orbits of spinning test particle in rotating boson star,"In this paper, we study the circular orbit of the spinning test particle in
the background of a rotating boson star. Using the pole-dipole approximation
and neglecting the back-reaction of the spinning test particle on the
spacetime, the equation of motion of the spinning test particle is described by
the Mathisson-Papapetrou-Dixon equation. We solve this equation under the
Tulczyjew spin-supplementary condition and obtain the four-momentum and
four-velocity of the spinning test particle. Quite different from the spinless
particle, the effective potential of the spinning particle with zero orbital
angular momentum goes to infinite at the center of the rotating boson star.
This will lead to the fact that the spinning particle can not pass through the
center of the boson star. However, when the spin angular momentum and orbital
angular momentum satisfy $2\bar{s}+\bar{l}=0$, the effective potential is not
divergent anymore and the spinning particle can pass through the center of the
rotating boson star. {We still investigate how the spin affects the structure
of the circular orbits and we find that the spin will induce the larger or
smaller regions of no circular orbits, unstable circular orbits, and stable
circular orbits.} Moreover, the radius and energy of the circular orbit will be
decreased or increased by the particle spin. These results will have an
important application in testing the gravitational waves in the boson star
background.",2201.01498v3
2022-11-08,From Elastic Spin to Phonon Spin: Symmetry and Fundamental Relations,"This work is mainly based on postgraduate lectures at Tongji University since
2020 spring. We firstly revisit the elastic spin and orbital angular momentum
[Proc. Natl. Acad. Sci. USA 115, 9951 (2018)] but more general for anisotropic
systems by applying Noether's theorem to the elastic Lagrangian and by applying
the symmetry argument in the field theory. Then, fundamental relations between
elastic energy flux and elastic spin are uncovered. In particular cases, the
wave spin is closely related to the vorticity of energy flux and momentum.
Secondly, we move forward from the elastic spin to revisit the phonon spin
[Fizika Tverdogo Tela 3, 2160 (1961)] by applying the second quantization to
elastic fields. We show that the uncovered phonon spin, a polarized
elastic-vibration quanta, is generally not restricted to transverse phonon
modes, but applying to general phonon modes, such as the longitudinal phonon
modes, surface phonon modes, and hybridized phonon modes, regarded as a
consequence of mode interferences. The elastic spin and phonon spin originate
from the local rotating of the field polarization in time domain, not the local
circulation (vorticity) of displacement or velocity in space domain. It is
hopeful that the present results could advance the fundamental understanding of
phonon spin and elastic spin, and promote the spin phononics for hybrid quantum
sensing and technology with multiple degrees of freedom.",2211.04959v2
2023-09-11,Scalable spin squeezing in two-dimensional arrays of dipolar large-$S$ spins,"Controlling the quantum many-body state of arrays of qudits, possessing a
large local Hilbert space, opens the path to a broad range of possibilities for
many-particle entanglement, interesting both for fundamental quantum science,
as well as for potential metrological applications. In this work we
theoretically show that the spin-spin interactions realized in two-dimensional
Mott insulators of large-spin magnetic atoms (such as Cr, Er or Dy) lead to
scalable spin squeezing along the non-equilibrium unitary evolution initialized
in a coherent spin state. An experimentally relevant perturbation to the
collective squeezing dynamics is offered by a quadratic Zeeman shift, which
leads instead to squeezing of individual spins. Making use of a truncated
cumulant expansion for the quantum fluctuations of the spin array, we show
that, for sufficiently small quadratic shifts, the spin squeezing dynamics is
akin to that produced by the paradigmatic one-axis-twisting (OAT) model -- as
expected from an effective separation between collective spin and spin-wave
variables. Spin squeezing with OAT-like scaling is shown to be protected by the
robustness of long-range ferromagnetic order to quadratic shifts in the
equilibrium phase diagram of the system, that we reconstruct via quantum Monte
Carlo and mean-field theory.",2309.05368v1
2023-11-06,Three-dimensional checkerboard spin structure on a breathing pyrochlore lattice,"The standard approach to realize a spin liquid state is through magnetically
frustrated states, relying on ingredients such as the lattice geometry,
dimensionality, and magnetic interaction type of the spins. While Heisenberg
spins on a pyrochlore lattice with only antiferromagnetic nearest neighbors
interactions are theoretically proven disordered, spins in real systems
generally include longer-range interactions. The spatial correlations at longer
distances typically stabilize a long-range order rather than enhancing a spin
liquid state. Both states can, however, be destroyed by short-range static
correlations introduced by chemical disorder. Here, using disorder-free
specimens with a clear long-range antiferromagnetic order, we refine the spin
structure of the Heisenberg spinel ZnFe2O4 through neutron magnetic
diffraction. The unique wave vector (1, 0, 1/2) leads to a spin structure that
can be viewed as alternatively stacked ferromagnetic and antiferromagnetic
tetrahedra in a three-dimensional checkerboard form. Stable coexistence of
these opposing types of clusters is enabled by the bipartite
breathing-pyrochlore crystal structure, leading to a second order phase
transition at 10 K. The diffraction intensity of ZnFe2O4 is an exact complement
to the inelastic scattering intensity of several chromate spinel systems which
are regarded as model classical spin liquids. Our results challenge this
attribution, and suggest instead of the six-spin ring-mode, spin excitations in
chromate spinels are closely related to the (1, 0, 1/2) type of spin order and
the four-spin ferromagnetic cluster locally at one tetrahedron.",2311.02823v1
2001-07-19,Anomalies of ac driven solitary waves with internal modes: Nonparametric resonances induced by parametric forces,"We study the dynamics of kinks in the $\phi^4$ model subjected to a
parametric ac force, both with and without damping, as a paradigm of solitary
waves with internal modes. By using a collective coordinate approach, we find
that the parametric force has a non-parametric effect on the kink motion.
Specifically, we find that the internal mode leads to a resonance for
frequencies of the parametric driving close to its own frequency, in which case
the energy of the system grows as well as the width of the kink. These
predictions of the collective coordinate theory are verified by numerical
simulations of the full partial differential equation. We finally compare this
kind of resonance with that obtained for non-parametric ac forces and conclude
that the effect of ac drivings on solitary waves with internal modes is exactly
the opposite of their character in the partial differential equation.",0107397v1
2004-09-14,Remnant superfluid collective phase oscillations in the normal state of systems with resonant pairing,"The signature of superfluidity in bosonic systems is a sound wave-like
spectrum of the single particle excitations which in the case of strong
interactions is roughly temperature independent. In fermionic systems, where
fermion pairing arises as a resonance phenomenon between free fermions and
paired fermionic states (examples are: the atomic gases of lithium or potassium
controlled by a Feshbach resonance, polaronic systems in the intermediary
coupling regime, d-wave hole pairing in the strongly correlated Hubbard
system), remnants of such superfluid characteristics are expected to be visible
in the normal state. The single particle excitations maintain there a sound
wave like structure for wave vectors above a certain q_{min}(T) where they
practically coincide there with the spectrum of the superfluid phase for
T<T_{c}. Upon approaching the transition from above this region in q-space
extends down to small momenta, except for a narrow region around q=0 where such
modes change into damped free particle",0409359v1
2005-07-25,Dissociation of Feshbach Molecules into Different Partial Waves,"Ultracold molecules can be associated from ultracold atoms by ramping the
magnetic field through a Feshbach resonance. A reverse ramp dissociates the
molecules. Under suitable conditions, more than one outgoing partial wave can
be populated. A theoretical model for this process is discussed here in detail.
The model reveals the connection between the dissociation and the theory of
multichannel scattering resonances. In particular, the decay rate, the
branching ratio, and the relative phase between the partial waves can be
predicted from theory or extracted from experiment. The results are applicable
to our recent experiment in 87Rb, which has a d-wave shape resonance.",0507580v2
2000-09-19,Energetic Cosmic Rays observed by the resonant gravitational wave detector NAUTILUS,"Cosmic ray showers interacting with the resonant mass gravitational wave
antenna NAUTILUS have been detected. The experimental results show large
signals at a rate much greater than expected. The largest signal corresponds to
an energy release in NAUTILUS of 87 TeV. We remark that a resonant mass
gravitational wave detector used as particle detector has characteristics
different from the usual particle detectors, and it could detect new features
of cosmic rays. Among several possibilities, one can invoke unexpected
behaviour of superconducting Aluminium as particle detector, producing enhanced
signals, the excitation of non-elastic modes with large energy release or
anomalies in cosmic rays (for instance, the showers might include exotic
particles as nuclearites or Q-balls). Suggestions for explaining these
observations are solicited.",0009066v1
2001-05-04,Comparison of advanced gravitational-wave detectors,"We compare two advanced designs for gravitational-wave antennas in terms of
their ability to detect two possible gravitational wave sources. Spherical,
resonant mass antennas and interferometers incorporating resonant sideband
extraction (RSE) were modeled using experimentally measurable parameters. The
signal-to-noise ratio of each detector for a binary neutron star system and a
rapidly rotating stellar core were calculated. For a range of plausible
parameters we found that the advanced LIGO interferometer incorporating RSE
gave higher signal-to-noise ratios than a spherical detector resonant at the
same frequency for both sources. Spheres were found to be sensitive to these
sources at distances beyond our galaxy. Interferometers were sensitive to these
sources at far enough distances that several events per year would be expected.",0105020v2
2003-01-15,Thermal and back-action noises in dual-sphere gravitational-waves detectors,"We study the sensitivity limits of a broadband gravitational-waves detector
based on dual resonators such as nested spheres. We determine both the thermal
and back-action noises when the resonators displacements are read-out with an
optomechanical sensor. We analyze the contributions of all mechanical modes,
using a new method to deal with the force-displacement transfer functions in
the intermediate frequency domain between the two gravitational-waves sensitive
modes associated with each resonator. This method gives an accurate estimate of
the mechanical response, together with an evaluation of the estimate error. We
show that very high sensitivities can be reached on a wide frequency band for
realistic parameters in the case of a dual-sphere detector.",0301048v1
1997-04-24,The Preheating - Gravitational Wave Correspondence,"The gravitational wave equations form a parametric resonance system during
oscillatory reheating after inflation, when cast in terms of the electric and
magnetic parts of the Weyl tensor. This is in direct analogy with preheating.
For chaotic inflation with a quadratic potential, this analogy is exact. The
resulting amplification of the gravitational wave spectrum begins in the broad
resonance regime for chaotic inflation but quickly moves towards narrow
resonance. This increases the amplitude and breaks the scale invariance of the
tensor spectrum generated during inflation, an effect which may be detectable.
The parametric amplification is absent, however, in 1st-order phase transition
models and ""warm"" inflationary models with continuous entropy production.",9704399v3
2004-08-31,Open nonradiative cavities as millimeter wave single-mode resonators,"Open single-mode metallic cavities operating in nonradiative configurations
are proposed and demonstrated. Starting from well-known dielectric resonators,
possible nonradiative cavities have been established; their behavior on the
fundamental TE011 mode has been predicted on the basis of general
considerations. As a result, very efficient confinement properties are expected
for a wide variety of open structures having rotational invariance. Test
cavities realized having in mind practical millimeter wave constraints have
been characterized at microwave frequencies. The field distribution of some
relevant configurations has been modeled by means of a finite-element numerical
method. The obtained results confirm the expected high performances on widely
open configurations. A possible excitation of the proposed resonators
exploiting their nonradiative character is discussed, and the resulting overall
ease of realization enlightened in view of millimeter wave employments.",0408130v2
2005-05-31,Resonant backward scattering of light by a two-side-open subwavelength metallic slit,"The backward scattering of TM-polarized light by a two-side-open
subwavelength slit in a metal film is analyzed. We show that the reflection
coefficient versus wavelength possesses a Fabry-Perot-like dependence that is
similar to the anomalous behavior of transmission reported in the study [Y.
Takakura, Phys. Rev. Lett. \textbf{86}, 5601 (2001)]. The open slit totally
reflects the light at the near-to-resonance wavelengths. In addition, we show
that the interference of incident and resonantly backward-scattered light
produces in the near-field diffraction zone a spatially localized wave whose
intensity is 10-10$^3$ times greater than the incident wave, but one order of
magnitude smaller than the intra-cavity intensity. The amplitude and phase of
the resonant wave at the slit entrance and exit are different from that of a
Fabry-Perot cavity.",0505211v2
2000-05-27,Interference at quantum transitions: lasing without inversion and resonant four-wave mixing in strong fields at Doppler-broadened transitions,"An influence of nonlinear interference processes at quantum transitions under
strong resonance electromagnetic fields on absorption, amplification and
refractive indices as well as on four-wave mixing processes is investigated.
Doppler broadening of the coupled transitions, incoherent excitation,
relaxation processes, as well as power saturation processes associated with the
coupled levels are taken into account. Both closed (ground state is involved)
and open (only excited states are involved) energy level configurations are
considered. Common expressions are obtained which allow one to analyze the
optical characteristics (including gain without inversion and enhanced
refractive index at vanishing absorption) for various V, Lambda and H
configurations of interfering transitions by a simple substitution of
parameters. Similar expressions for resonant four-wave mixing in Raman
configurations are derived too. Crucial role of Doppler broadening is shown.
The theory is applied to numerical analysis of some recent and potential
experiments.",0005118v1
2006-06-18,Atom Lithography with Near-Resonant Light Masks: Quantum Optimization Analysis,"We study the optimal focusing of two-level atoms with a near resonant
standing wave light, using both classical and quantum treatments of the
problem. Operation of the focusing setup is considered as a nonlinear spatial
squeezing of atoms in the thin- and thick-lens regimes. It is found that the
near-resonant standing wave focuses the atoms with a reduced background in
comparison with far-detuned light fields. For some parameters, the quantum
atomic distribution shows even better localization than the classical one.
Spontaneous emission effects are included via the technique of quantum Monte
Carlo wave function simulations. We investigate the extent to which
non-adiabatic and spontaneous emission effects limit the achievable minimal
size of the deposited structures.",0606145v1
2006-10-09,Features of Magneto-Optical Resonances in an Elliptically Polarized Traveling Light Wave,"The parameters of nonlinear absorption magneto-optical resonances in the
Hanle configuration have been studied as functions of the ellipticity of a
traveling light wave. It has been found that these parameters (amplitude,
width, and amplitude-to-width ratio) depend strongly on the polarization of the
light wave. In particular, the resonance amplitude can increase by more than an
order of magnitude when the polarization changes from linear to optimal
elliptic. It has been shown that this effect is associated with the Doppler
frequency shift for atoms in a gas. The theoretical results have been
corroborated in experiments in Rb vapor.",0610053v1
2007-07-24,New results on the Roper resonance and the P_{11} partial wave,"Properties of the Roper resonance, the first scalar excitation of the
nucleon, are determined. Pole positions and residues of the $P_{11}$ partial
wave are studied in a combined analysis of pion- and photo-induced reactions.
We find the Roper pole at $\{(1371\pm7)-i(92\pm10)\}$ MeV and an elasticity of
$0.61\pm 0.03$. The largest decay coupling is found for the $N\sigma$
($\sigma=(\pi\pi)$-$S$-wave). The analysis is based on new data on $\gamma p\to
p\pi^0\pi^0$ for photons in the energy range from the two-pion threshold to 820
MeV from TAPS at Mainz and from 0.4 to 1.3 GeV from Crystal Barrel at Bonn and
includes further data from other experiments. The partial wave analysis
excludes the possibility that the Roper resonance is split into two states with
different partial decay widths.",0707.3591v4
2008-02-01,The transport of cosmic rays in self-excited magnetic turbulence,"The process of diffusive shock acceleration relies on the efficacy with which
hydromagnetic waves can scatter charged particles in the precursor of a shock.
The growth of self-generated waves is driven by both resonant and non-resonant
processes. We perform high-resolution magnetohydrodynamic simulations of the
non-resonant cosmic-ray driven instability, in which the unstable waves are
excited beyond the linear regime. In a snapshot of the resultant field,
particle transport simulations are carried out. The use of a static snapshot of
the field is reasonable given that the Larmor period for particles is typically
very short relative to the instability growth time. The diffusion rate is found
to be close to, or below, the Bohm limit for a range of energies. This provides
the first explicit demonstration that self-excited turbulence reduces the
diffusion coefficient and has important implications for cosmic ray transport
and acceleration in supernova remnants.",0802.0109v1
2008-05-20,Double optical spring enhancement for gravitational wave detectors,"Currently planned second-generation gravitational-wave laser interferometers
such as Advanced LIGO exploit the extensively investigated signal-recycling
(SR) technique. Candidate Advanced LIGO configurations are usually designed to
have two resonances within the detection band, around which the sensitivity is
enhanced: a stable optical resonance and an unstable optomechanical resonance -
which is upshifted from the pendulum frequency due to the so-called
optical-spring effect. Alternative to a feedback control system, we propose an
all-optical stabilization scheme, in which a second optical spring is employed,
and the test mass is trapped by a stable ponderomotive potential well induced
by two carrier light fields whose detunings have opposite signs. The double
optical spring also brings additional flexibility in re-shaping the noise
spectral density and optimizing toward specific gravitational-wave sources. The
presented scheme can be extended easily to a multi-optical-spring system that
allows further optimization.",0805.3096v1
2008-12-18,Spiral density wave triggering of star formation in SA and SAB galaxies,"Azimuthal color (age) gradients across spiral arms are one of the main
predictions of density wave theory; gradients are the result of star formation
triggering by the spiral waves. In a sample of 13 spiral galaxies of types A
and AB, we find that 10 of them present regions that match the theoretical
predictions. By comparing the observed gradients with stellar population
synthesis models, the pattern speed and the location of major resonances have
been determined. The resonance positions inferred from this analysis indicate
that 9 of the objects have spiral arms that extend to the outer Lindblad
resonance (OLR); for one of the galaxies, the spiral arms reach the corotation
radius. The effects of dust, and of stellar densities, velocities, and
metallicities on the color gradients are also discussed.",0812.3647v1
2009-07-14,Las ondas viajeras son los ojos nuevos de la resonancia en medicina,"Magnetic Resonance Imaging is one of the most versatile experimental
techniques in chemistry, physics and biology, providing insight into the
structure and dynamics of matter at the molecular scale. A group led by Klaas
Pruessmann at ETH Zurich (Brunner, D.O. et al. Travelling-wave nuclear magnetic
resonance. Nature 457;994:2009) has now demonstrated an alternative approach
that radically departs from the conventional view of MRI as a near-field,
inductive technique. This approach also required that radiofre-quency wave is
propagated from an antenna positioned at one end of the cylindrical magnet;
this wave travels through the specimen within the bore of the magnet, producing
signals that are received either by the same antenna or by another one
positioned at the opposite end. The resulting instrument considerably extends
the scale of imaging possible with Magnetic Resonance Imaging, and initial
tests demonstrated uniform high-field imaging of a variety of samples, both
inorganic and inorganic.",0907.2446v1
2009-10-07,Slow Wave Phenomena in Photonic Crystals,"Slow light in photonic crystals and other periodic structures is associated
with stationary points of the photonic dispersion relation, where the group
velocity of light vanishes. We show that in certain cases, the vanishing group
velocity is accompanied by the so-called frozen mode regime, when the incident
light can be completely converted into the slow mode with huge diverging
amplitude. The frozen mode regime is a qualitatively new wave phenomenon -- it
does not reduce to any known electromagnetic resonance. Formally, the frozen
mode regime is not a resonance, in a sense that it is not particularly
sensitive to the size and shape of the photonic crystal. The frozen mode regime
is more robust and powerful, compared to any known slow-wave resonance. It has
much higher tolerance to absorption and structural imperfections.",0910.1220v4
2010-02-26,Resonance Fluorescence of a Single Artificial Atom,"An atom in open space can be detected by means of resonant absorption and
reemission of electromagnetic waves, known as resonance fluorescence, which is
a fundamental phenomenon of quantum optics. We report on the observation of
scattering of propagating waves by a single artificial atom. The behavior of
the artificial atom, a superconducting macroscopic two-level system, is in a
quantitative agreement with the predictions of quantum optics for a pointlike
scatterer interacting with the electromagnetic field in one-dimensional open
space. The strong atom-field interaction as revealed in a high degree of
extinction of propagating waves will allow applications of controllable
artificial atoms in quantum optics and photonics.",1002.4944v1
2010-06-04,Revisiting the wire medium: a resonant metalens,"This article is the first one in a series of two dealing with the concept of
""resonant metalens"" we recently introduced [Phys. Rev. Lett. 104, 203901
(2010)]. Here, we focus on the physics of a medium with finite dimensions
consisting on a square lattice of parallel conducting wires arranged on a
sub-wavelength scale. This medium supports electromagnetic fields that vary
much faster than the operating wavelength. We show that such modes are
dispersive due to the finiteness of the medium. Their dispersion relation is
established in a simple way, a link with designer plasmons is made, and the
canalization phenomenon is reinterpreted at the light of our model. We explain
how to take advantage of this dispersion in order to code sub-wavelength wave
fields in time. Finally, we show that the resonant nature of the medium ensures
an efficient coupling of these modes with free space propagating waves and,
thanks to the Purcell effect, with a source placed in the near field of the
medium.",1006.0829v3
2011-02-16,Hybrid squeezing of solitonic resonant radiation in photonic crystal fibers,"We report on the existence of a novel kind of squeezing in photonic crystal
fibers which is conceptually intermediate between the four-wave mixing induced
squeezing, in which all the participant waves are monochromatic waves, and the
self-phase modulation induced squeezing for a single pulse in a coherent state.
This hybrid squeezing occurs when an arbitrary short soliton emits
quasi-monochromatic resonant radiation near a zero group velocity dispersion
point of the fiber. Photons around the resonant frequency become strongly
correlated due to the presence of the classical soliton, and a reduction of the
quantum noise below the shot noise level is predicted.",1102.3405v1
2011-04-25,Relativistic acceleration of Landau resonant particles as a consequence of Hopf bifurcations,"Using bifurcation theory on a dynamical system simulating the interaction of
a particle with an obliquely propagating wave in relativistic regimes, we
demonstrate that uniform acceleration arises as a consequence of Hopf
bifurcations of Landau resonant particles. The acceleration process arises as a
form of surfatron established through the locking in pitch angle, gyrophase,
and physical trapping along the wave-vector direction. Integrating the
dynamical system for large amplitudes ($\delta B/B_0\sim0.1$) obliquely
propagating waves, we find that electrons with initial energies in the keV
range can be accelerated to MeV energies on timescales of the order of
milliseconds. The Hopf condition of Landau resonant particles could underlie
some of the most efficient energization of particles in space and astrophysical
plasmas.",1104.4760v2
2012-05-30,Quantum-defect theory of resonant charge exchange,"We apply the quantum-defect theory for $-1/R^4$ potential to study the
resonant charge exchange process. We show that by taking advantage of the
partial-wave-insensitive nature of the formulation, resonant charge exchange of
the type of $^1$S+$^2$S can be accurately described over a wide range of
energies using only three parameters, such as the \textit{gerade} and the
\textit{ungerade} $s$ wave scattering lengths, and the atomic polarizability,
even at energies where many partial waves contribute to the cross sections. The
parameters can be determined experimentally, without having to rely on accurate
potential energy surfaces, of which few exist for ion-atom systems. The theory
further relates ultracold interactions to interactions at much higher
temperatures.",1205.6549v1
2012-07-10,The Heart of Fidelity,"The multi-electron wave function of an interacting electron system depends on
the size of the system, i.e. the number of electrons. Here the question
investigated is how the wave function changes for a symmetric Friedel-Anderson
impurity when the volume is doubled. It turns out that for sufficiently large
volume (when the level spacing is smaller than the resonance width) the change
in the wave function can be expressed in terms of a universal single-electron
state |q> centered at the Fermi level. This electron state is independent of
the number of electrons and independent of the parameters of the
Friedel-Anderson impurity. It is even the same universal state for a Kondo
impurity and a symmetric Friedel impurity independent of any parameter. The
only requirement is that the impurity has a resonance exactly at the Fermi
level and that the level spacing is smaller than the resonance width. This
result clarifies recent fidelity calculations.",1207.2502v1
2013-05-10,Symmetry and resonant modes in platonic grating stacks,"We study the flexural wave modes existing in finite stacks of gratings
containing rigid, zero-radius pins. We group the modes into even and odd
classes, and derive dispersion equations for each. We study the recently
discovered EDIT (elasto-dynamically inhibited transmission) phenomenon, and
relate it to the occurrence of trapped waves of even and odd symmetries being
simultaneously resonant. We show how the EDIT interaction may be steered over a
wide range of frequencies and angles, using a strategy in which the
single-grating reflectance is kept high, so enabling the quality factors of the
even and odd resonances to be kept large.",1305.2300v1
2013-05-22,Integral Equation Analysis of Plane Wave Scattering by Coplanar Graphene-Strip Gratings in the THz Range,"The plane wave scattering and absorption by finite and infinite gratings of
free-space standing infinitely long graphene strips are studied in the THz
range. A novel numerical approach, based on graphene surface impedance,
hyper-singular integral equations, and the Nystrom method, is proposed. This
technique guarantees fast convergence and controlled accuracy of computations.
Reflectance, transmittance, and absorbance are carefully studied as a function
of graphene and grating parameters, revealing the presence of surface plasmon
resonances. Specifically, larger graphene relaxation times increases the number
of resonances in the THz range, leading to higher wave transmittance due to the
reduced losses; on the other hand an increase of graphene chemical potential
up-shifts the frequency of plasmon resonances. It is also shown that a
relatively low number of graphene strips (>10) are able to reproduce Rayleigh
anomalies. These features make graphene strips good candidates for many
applications, including tunable absorbers and frequency selective surfaces.",1305.5172v1
2013-08-18,Optical isolation via unidirectional resonant photon tunneling,"We show that tri-layer structures combining epsilon-negative and
magneto-optical material layers can exhibit unidirectional resonant photon
tunneling phenomena that can discriminate between circularly-polarized (CP)
waves of given handedness impinging from opposite directions, or between CP
waves with different handedness impinging from the same direction. This
physical principle, which can also be interpreted in terms of a
Fabry-Perot-type resonance, may be utilized to design compact optical isolators
for CP waves. Within this framework, we derive simple analytical conditions and
design formulae, and quantitatively assess the isolation performance, also
taking into account the unavoidable imperfections and nonidealities.",1308.3845v4
2013-11-16,High-efficiency degenerate four wave-mixing in triply resonant nanobeam cavities,"We demonstrate high-efficiency, degenerate four-wave mixing in triply
resonant Kerr $\chi^(3)$ photonic crystal (PhC) nanobeam cavities. Using a
combination of temporal coupled mode theory and nonlinear finite-difference
time-domain (FDTD) simulations, we study the nonlinear dynamics of resonant
four-wave mixing processes and demonstrate the possibility of observing
high-efficiency limit cycles and steady-state conversion corresponding to
$\approx 100$% depletion of the pump light at low powers, even including
effects due to losses, self- and cross-phase modulation, and imperfect
frequency matching. Assuming operation in the telecom range, we predict close
to perfect quantum efficiencies at reasonably low $\sim$ 50 mW input powers in
silicon micrometer-scale cavities.",1311.4100v1
2013-12-22,Sub-terahertz sound excitation and detection by long Josephson junction,"The paper reports on experimental observation of sub-terahertz sound wave
generation and detection by a long Josephson junction. This effect was
discovered at spectral measurements of sub-terahertz electromagnetic emission
from a flux-flow oscillator (FFO) deposited on optically polished Si substrate.
The back action of the acoustic waves generated by the FFO and reflected by the
bottom surface of the Si substrate results in the appearance of resonant steps
in the FFO IVCs with spacing as small as 29 nV for 0.3 mm substrate thickness;
these steps manifest themselves in a pronounced resonant structure in the
emission spectra with spacing of about 14 MHz precisely according to the
Josephson relation. The mechanism of acoustic wave generation and detection by
the FFO is discussed; a possibility for employing the discovered effect for FFO
frequency stabilization has been demonstrated. A simple and reliable way to
suppress the superfine resonant structure has been developed and proven; this
invention allows for continuous frequency tuning and FFO phase locking at any
desired frequency, all of which is vitally important for most applications.",1312.6377v2
2014-03-02,Universal wave functions structure in mixed systems,"When a regular classical system is perturbed, non-linear resonances appear as
prescribed by the KAM and Poincar\`{e}-Birkhoff theorems. Manifestations of
this classical phenomena to the morphologies of quantum wave functions are
studied in this letter. We reveal a systematic formation of an universal
structure of localized wave functions in systems with mixed classical dynamics.
Unperturbed states that live around invariant tori are mixed when they collide
in an avoided crossing if their quantum numbers differ in a multiple to the
order of the classical resonance. At the avoided crossing eigenstates are
localized in the island chain or in the vicinity of the unstable periodic orbit
corresponding to the resonance. The difference of the quantum numbers
determines the excitation of the localized states which is reveled using the
zeros of the Husimi distribution.",1403.0275v1
2014-03-07,On the possible mechanism to form the radio emission spectrum of the Crab pulsar,"In the present paper a self-consistent theory, explaining shape of the
observed phase-averaged radio spectrum in the frequency range from 100MHz to
10GHz is presented. The radio waves are assumed to be generated near the light
cylinder through the cyclotron resonance. The cyclotron instability provides
excitement of the electron-positron plasma eigen-waves, which come in radio
domain when the resonant particles are the most energetic primary beam
electrons. It is widely accepted that the distribution function of relativistic
particles is one-dimensional at the pulsar surface. The generated waves react
back on the resonant particles causing their diffusion in the perpendicular
direction to the magnetic field and violating the one-dimensionality, which
switches on the synchrotron radiation process. The synchrotron emission of the
beam electrons provides generation of high-energy $\gamma$-rays simultaneously
with the radio emission, that explains the observed pulse phase-coincidence in
these energy domains. The theory provides a power-law radio spectrum with the
spectral index equal to $3.7$, coming in agreement with the observations.",1403.1765v1
2014-04-03,Theory of time-resolved non-resonant x-ray scattering for imaging ultrafast coherent electron motion,"Future ultrafast x-ray light sources might image ultrafast coherent electron
motion in real-space and in real-time. For a rigorous understanding of such an
imaging experiment, we extend the theory of non-resonant x-ray scattering to
the time-domain. The role of energy resolution of the scattering detector is
investigated in detail. We show that time-resolved non-resonant x-ray
scattering with no energy resolution offers an opportunity to study
time-dependent electronic correlations in non- equilibrium quantum systems.
Furthermore, our theory presents a unified description of ultrafast x-ray
scattering from electronic wave packets and the dynamical imaging of ultrafast
dynamics using inelastic x-ray scattering by Abbamonte and co-workers. We
examine closely the relation of the scattering signal and the linear density
response of electronic wave packets. Finally, we demonstrate that time-resolved
x-ray scattering from a crystal consisting of identical electronic wave packets
recovers the instantaneous electron density.",1404.0796v1
2014-05-28,Resonant Bloch-wave beatings,"We introduce Bloch-wave beatings in arrays of multimode periodically bent
waveguides with a transverse refractive index gradient. The new phenomenon
manifests itself in the periodic drastic increase of the amplitude of the Bloch
oscillations that accompanies resonant conversion of modes guided by the
individual waveguides. The Bloch-wave beatings are found to be most pronounced
when the length of the resonant mode conversion substantially exceeds the
longitudinal period of the Bloch oscillations. The beating frequency decreases
when the amplitude of waveguide bending decreases, while the beating amplitude
is restricted by the amplitude of the Bloch oscillations that emerge from the
second allowed band of the Floquet-Bloch lattice spectrum.",1405.7203v1
2014-10-04,Sub-optical wavelength acoustic wave modulation of integrated photonic resonators at microwave frequencies,"Light-sound interactions have long been exploited in various acousto-optic
devices based on bulk crystalline materials. Conventionally these devices
operate in megahertz frequency range where the acoustic wavelength is much
longer than the optical wavelength and a long interaction length is required to
attain significant coupling. With nanoscale transducers, acoustic waves with
sub-optical wavelengths can now be excited to induce strong acousto-optic
coupling in nanophotonic devices. Here we demonstrate microwave frequency
surface acoustic wave transducers co-integrated with nanophotonic resonators on
piezoelectric aluminum nitride substrates. Acousto-optic modulation of the
resonance modes at above 10 GHz with the acoustic wavelength significantly
below the optical wavelength is achieved. The phase and modal matching
conditions in this scheme are investigated for efficient modulation. The new
acousto-optic platform can lead to novel optical devices based on nonlinear
Brillouin processes and provides a direct, wideband link between optical and
microwave photons for microwave photonics and quantum optomechanics.",1410.1008v1
2015-02-08,Parametric excitation of multiple resonant radiations from localized wavepackets,"Fundamental physical phenomena such as laser-induced ionization, driven
quantum tunneling, Faraday waves, Bogoliubov quasiparticle excitations, and the
control of new states of matter rely on time-periodic driving of the system. A
remarkable property of such driving is that it can induce the localized (bound)
states to resonantly couple to the continuum. Therefore experiments that allow
for enlightening and controlling the mechanisms underlying such coupling are of
paramount importance. We implement such an experiment in a special fiber optics
system characterized by a dispersion oscillating along the propagation
coordinate, which mimics ""time"". The quasi-momentum associated with such
periodic perturbation is responsible for the efficient coupling of energy from
the localized wave-packets sustained by the fiber nonlinearity into
free-running linear dispersive waves (continuum), at multiple resonant
frequencies. Remarkably, the observed resonances can be explained by means of a
unified approach, regardless of the fact that the localized state is a
soliton-like pulse or a shock front.",1502.02266v1
2015-06-18,Search for sub-eV scalar and pseudoscalar resonances via four-wave mixing with a laser collider,"The quasi-parallel photon-photon scattering by combining two-color laser
fields is an approach to produce resonant states of low-mass fields in
laboratory. In this system resonances can be probed via the four-wave mixing
process in the vacuum. A search for scalar and pseudoscalar fields was
performed by combining 9.3 $\mu$J/0.9 ps Ti-Sapphire laser and 100 $\mu$J/9 ns
Nd:YAG laser. No significant signal of four-wave mixing was observed. We
provide the upper limits on the coupling-mass relation for scalar and
pseudoscalar fields, respectively, at a 95\% confidence level in the mass
region below 0.15~eV.",1506.05581v1
2015-10-10,Resonant wavepackets and shock waves in an atomtronic SQUID,"The fundamental dynamics of ultracold atomtronic devices are reflected in
their phonon modes of excitation. We probe such a spectrum by applying a
harmonically driven potential barrier to a $^{23}$Na Bose-Einstein condensate
in a ring-shaped trap. This perturbation excites phonon wavepackets. When
excited resonantly, these wavepackets display a regular periodic structure. The
resonant frequencies depend upon the particular configuration of the barrier,
but are commensurate with the orbital frequency of a Bogoliubov sound wave
traveling around the ring. Energy transfer to the condensate over many cycles
of the periodic wavepacket motion causes enhanced atom loss from the trap at
resonant frequencies. Solutions of the time-dependent Gross-Pitaevskii equation
exhibit quantitative agreement with the experimental data. We also observe the
generation of supersonic shock waves under conditions of strong excitation, and
collisions of two shock wavepackets.",1510.02968v1
2015-12-07,Mechanism for femtosecond laser-induced periodic subwavelength structures on solid surface: surface two-plasmon resonance,"We present that surface two-plasmon resonance (STPR) in electron plasma sheet
produced by femtosecond laser irradiating metal surface is the self-formation
mechanism of periodic subwavelength ripple structures. Peaks of overdense
electrons formed by resonant two-plasmon wave pull bound ions out of the metal
surface and thus the wave pattern of STPR is ""carved"" on the surface by Coulomb
ablation (removal) resulting from the strong electrostatic field induced by
charge separation. To confirm the STPR model, we have performed analogical
carving experiments by two laser beams with perpendicular polarizations. The
results explicitly show that two wave patterns of STPR are independently carved
on the exposure area of target surface. The time-scale of ablation dynamics and
the electron temperature in ultrafast interaction are also verified by
time-resolved spectroscopy experiment and numerical simulation, respectively.
The present model can self-consistently explain the formation of subwavelength
ripple structures even with spatial periods shorter than half of the laser
wavelength, shedding light on the understanding of ultrafast laser-solid
interaction.",1512.01966v1
2016-02-16,Energy correlations of photon pairs generated by a silicon microring resonator probed by Stimulated Four Wave Mixing,"Compact silicon integrated devices, such as micro-ring resonators, have
recently been demonstrated as efficient sources of quantum correlated photon
pairs. The mass production of integrated devices demands the implementation of
fast and reliable techniques to monitor the device performances. In the case of
time-energy correlations, this is particularly challenging, as it requires high
spectral resolution that is not currently achievable in coincidence
measurements. Here we reconstruct the joint spectral density of photons pairs
generated by spontaneous four-wave mixing in a silicon ring resonator by
studying the corresponding stimulated process, namely stimulated four wave
mixing. We show that this approach, featuring high spectral resolution and
short measurement times, allows one to discriminate between nearly-uncorrelated
and highly-correlated photon pairs.",1602.04962v1
2016-04-30,Acoustic Localization Phenomena in Ferroelectric Nanophononic Devices,"The engineering of phononic resonances in ferroelectric structures appears as
a new knob in the design and realization of novel multifunctional devices. In
this work we experimentally study phononic resonators based on insulating
(BaTiO3, SrTiO3) and metallic (SrRuO3) oxides. We experimentally demonstrate
the confinement of acoustic waves in the 100 GHz frequency range in a phonon
nanocavity, the time and spatial beatings resulting from the coupling of two
different hybrid nanocavities forming an acoustic molecule, and the direct
measurement of Bloch-like oscillations of acoustic phonons in a system formed
by 10 coupled resonators. By means of coherent phonon generation techniques we
study the phonon dynamics directly in the time-domain. The metallic SrRuO3
introduces a local phonon generator and transducer that allows for the spatial,
spectral and time-domain monitoring of the complex generated waves. Our results
introduce ferroelectric cavity systems as a new tool for the study of complex
wave localization phenomena at the nanoscale.",1605.00147v1
2016-07-01,Acoustic Prism for Continuous Beam Steering Based on Piezoelectric Metamaterial,"This paper investigates an acoustic prism for continuous acoustic beam
steering by a simple frequency sweep. This idea takes advantages of acoustic
wave velocity shifting in metamaterials in the vicinity of local resonance. We
apply this concept into the piezoelectric metamaterial consisting of host
medium and piezoelectric LC shunt. Theoretical modeling and FEM simulations are
carried out. It is shown that the phase velocity of acoustic wave changes
dramatically in the vicinity of local resonance. The directions of acoustic
wave can be adjusted continuously between 2 to 16 degrees by a simple sweep of
the excitation frequency. Such an electro-mechanical coupling system has a
feature of adjusting local resonance without altering the mechanical part of
the system.",1607.00239v1
2016-09-07,Controlling flexural waves in semi-infinite platonic crystals,"We address the problem of scattering and transmission of a plane flexural
wave through a semi-infinite array of point scatterers/resonators, which take a
variety of physically interesting forms. The mathematical model accounts for
several classes of point defects, including mass-spring resonators attached to
the top surface of the flexural plate and their limiting case of concentrated
point masses. We also analyse the special case of resonators attached to
opposite faces of the plate. The problem is reduced to a functional equation of
the Wiener-Hopf type, whose kernel varies with the type of scatterer
considered. A novel approach, which stems from the direct connection between
the kernel function of the semi-infinite system and the quasi-periodic Green's
functions for corresponding infinite systems, is used to identify special
frequency regimes. We thereby demonstrate dynamically anisotropic wave effects
in semi-infinite platonic crystals, with particular attention paid to designing
systems to exhibit dynamic neutrality (perfect transmission) and localisation
close to the structured interface.",1609.02787v1
2016-10-29,Rogue wave and a pair of resonance stripe solitons to a reduced generalized (3+1)-dimensional KP equation,"Based on the bilinear operator and symbol calculation, some lump solutions
are presented, rationally localized in all directions in the space, to a
reduced (3+1)-dimensional KP equation. The lump solutions all contain six
parameters, four of which must cater to the non-zero conditions so as to insure
the analyticity and rational localization, while the others are free. Then the
interaction between lump soliton and one stripe soliton is described and the
result shows that the lump soliton will be drowned or swallowed by the stripe
soliton. Furthermore, we extend this method to a new combination of positive
quadratic function and hyperbolic functions. Especially, it is interesting that
a rogue wave is found to be aroused by the interaction between lump soliton and
a pair of resonance stripe solitons. By choosing the values of the parameters,
the dynamic properties of lump solution, interaction between lump soliton and
one stripe soliton, rogue wave, generated by the interaction between lump
soliton and a pair of resonance solitons, are shown graphically.",1610.09507v1
2017-09-25,Wave Propagation in a Strongly Nonlinear Locally Resonant Granular Crystal,"In this work, we study the wave propagation in a recently proposed acoustic
structure, the locally resonant granular crystal. This structure is composed of
a one-dimensional granular crystal of hollow spherical particles in contact,
containing linear resonators. The relevant model is presented and examined
through a combination of analytical approximations (based on ODE and nonlinear
map analysis) and of numerical results. The generic dynamics of the system
involves a degradation of the well-known traveling pulse of the standard
Hertzian chain of elastic beads. Nevertheless, the present system is richer, in
that as the primary pulse decays, secondary ones emerge and eventually
interfere with it creating modulated wavetrains. Remarkably, upon suitable
choices of parameters, this interference ""distills"" a weakly nonlocal solitary
wave (a ""nanopteron""). This motivates the consideration of such nonlinear
structures through a separate Fourier space technique, whose results suggest
the existence of such entities not only with a single-side tail, but also with
periodic tails on both ends. These tails are found to oscillate with the
intrinsic oscillation frequency of the out-of-phase motion between the outer
hollow bead and its internal linear attachment.",1709.08629v1
2017-11-22,On the physical mechanism of three-wave instabilities -- resonance between positive- and negative-action modes,"Three-wave instability is a fundamental process that has important
applications in many branches of physics. It is widely accepted that the
resonant condition $\omega_{z}\approx\omega_{x}+\omega_{y}$ for participating
waves is the criteria for the onset of the instability. We show that this
condition is neither sufficient nor necessary, instead, the exact criteria for
the onset of the instability is that a positive-action mode resonates with a
negative-action mode. This mechanism is imposed by the topology and geometry of
the spectral space. Guided by this new theory, additional instability bands
previously unknown are discovered.",1711.08248v2
2018-01-10,Fano Resonances in Flat Band Networks,"Linear wave equations on Hamiltonian lattices with translational invariance
are characterized by an eigenvalue band structure in reciprocal space. Flat
band lattices have at least one of the bands completely dispersionless. Such
bands are coined flat bands. Flat bands occur in fine-tuned networks, and can
be protected by (e.g. chiral) symmetries. Recently a number of such systems
were realized in structured optical systems, exciton-polariton condensates, and
ultracold atomic gases. Flat band networks support compact localized modes.
Local defects couple these compact modes to dispersive states and generate Fano
resonances in the wave propagation. Disorder (i.e. a finite density of defects)
leads to a dense set of Fano defects, and to novel scaling laws in the
localization length of disordered dispersive states. Nonlinearities can
preserve the compactness of flat band modes, along with renormalizing (tuning)
their frequencies. These strictly compact nonlinear excitations induce tunable
Fano resonances in the wave propagation of a nonlinear flat band lattice.",1801.03210v2
2018-11-10,"Stimulated resonant inelastic x-ray scattering with chirped, broadband pulses","We present an approach for initiating and tracing ultra-fast electron
dynamics in core-excited atoms, molecules and solids. The approach is based on
stimulated resonant inelastic x-ray scattering induced by a single, chirped,
broadband XUV/x-ray pulse. A first interaction with this pulse prepares a
core-excited state wave packet by resonant core-excitation. A second
interaction with the pulse at a later time induces the transition to
valence-excited states which is associated with stimulated emission. The
preparation of the core-excited wave packet and the transition from the
core-excited states to the valence-excited states occur at distinct
chirp-dependent times. As a consequence, the stimulated emission carries
information about the time evolution of the core-excited state wave packet.",1811.04292v1
2018-11-28,Unidirectional frequency conversion in microring resonators for on-chip frequency-multiplexed single-photon sources,"Microring resonators are attractive for low-power frequency conversion via
Bragg-scattering four-wave-mixing due to their comb-like resonance spectrum.
However, conversion efficiency is limited to 50% due to the equal probability
of up- and down-conversion. Here, we demonstrate how two coupled microrings
enable highly directional conversion between the spectral modes of one of the
rings. An extinction between up- and down-conversion of more than 40 dB is
experimentally observed. Based on this method, we propose a design for on-chip
multiplexed single-photon sources that allow localized frequency modes to be
converted into propagating continuous-mode photon wave packets using a single
operation. The key is that frequency conversion works as a switch on both
spatial and spectral degrees of freedom of photons if the microring is
interferometrically coupled to a bus waveguide. Our numerical results show 99%
conversion efficiency into a propagating mode with a wave packet having a 90%
overlap with a Gaussian for a ratio between intrinsic and coupling quality
factors of 400.",1811.11741v1
2018-07-03,Bridging coupling bandgaps in nonlinear acoustic metamaterials,"Nonlinear acoustic metamaterials (NAMs) open new freedoms in exploiting novel
technologies for wave manipulations. Recently, the desired ultra-low and
ultra-broad-band wave suppressions were achieved by the chaotic bands in NAMs
[Nature Commun. 8, 1288 (2017)]. This work describes a remote interaction
mechanism in NAMs-bridging coupling of nonlinear locally resonant bandgaps.
Bridging bandgaps generate chaotic bands and share the negative mass between
nonlinear resonators. The bandwidth and the efficiency for the wave reduction
in chaotic bands can be manipulated effectively by modulating the frequency
distance between the bridging pair. Theoretical analyses on the triatomic model
containing two nonlinearly coupled resonances clarify the principle of bridging
bandgaps. NAM beams are created to demonstrate this mechanism experimentally by
including the bifurcations of periodic solutions. Our study extends the content
of NAMs and more nonlinear effects are anticipated based on this mechanism.",1807.01230v1
2018-07-09,Long-time existence for multi-dimensional periodic water waves,"We prove an extended lifespan result for the full gravity-capillary water
waves system with a $2$ dimensional periodic interface: for initial data of
sufficiently small size $\varepsilon$, smooth solutions exist up to times of
the order of $\varepsilon^{-5/3+}$, for almost all values of the gravity and
surface tension parameters. Besides the quasilinear nature of the equations,
the main difficulty is to handle the weak small divisors bounds for quadratic
and cubic interactions, growing with the size of the largest frequency. To
overcome this difficulty we use (1) the (Hamiltonian) structure of the
equations which gives additional smoothing close to the resonant hypersurfaces,
(2) another structural property, connected to time-reversibility, that allows
us to handle ""trivial"" cubic resonances, (3) sharp small divisors lower bounds
on three and four-waves modulation functions based on counting arguments, and
(4) partial normal form transformations and symmetrization arguments in the
Fourier space. Our theorem appears to be the first extended lifespan result for
quasilinear equations with non-trivial resonances on a multi-dimensional torus.",1807.02932v2
2017-12-29,Low frequency acoustic stop bands in cubic arrays of thick spherical shells with holes,"We analyse the propagation of pressure waves within a fluid filled with a
three-dimensional array of rigid coated spheres (shells). We first draw band
diagrams for corresponding Floquet-Bloch waves. We then dig a channel
terminated by a cavity within each rigid shell and observe the appearance of a
low frequency stop band. The underlying mechanism is that each holey shell now
acts as a Helmholtz resonator supporting a low frequency localized mode: Upon
resonance, pressure waves propagate with fast oscillations in the thin water
channel drilled in each shell and are localized in each fluid filled inner
cavity. The array of fluid filled shells is approximated by a simple mechanical
model of springs and masses allowing for asymptotic estimates of the low
frequency stop band. We finally propose a realistic design of periodic
macrocell with a large defect surrounded by 26 resonators connected by thin
straight rigid wires, which supports a localized mode in the low frequency stop
band.",1802.02043v1
2019-02-25,Electromagnetic waves propagation through an array of superconducting qubits: manifestations of non-equilibrium steady states of qubits,"We report a theoretical study of the electromagnetic waves (EWs) propagation
through an array of superconducting qubits, i.e. coherent two-level systems,
embedded in a low-dissipative transmission line. We focus on the near-resonant
case as the frequency of EWs $\omega \simeq \omega_q$, where $\omega_q$ is the
qubit frequency. In this limit we derive the effective dynamic nonlinear wave
equation allowing one to obtain the frequency dependent transmission
coefficient of EWs, $D(\omega)$. In the linear regime and a relatively wide
frequency region we obtain a strong resonant suppression of $D(\omega)$ in both
cases of a single qubit and chains composed of a large number of densely
arranged qubits. However, in narrow frequency regions a chain of qubits allows
the resonant transmission of EWs with greatly enhanced $D(\omega)$. In the
nonlinear regime realized for a moderate power of applied microwave radiation,
we predict and analyze various transitions between states characterized by high
and low values of $D(\omega)$. These transitions are manifestations of
nonequilibrium steady states of an array of qubits achieved in this regime.",1902.09207v1
2020-04-15,Light-Matter Interaction and Hybrid Vector Breather,"The nonlinear coherent interaction of light with the dispersive and Kerr-type
third-order susceptibility medium containing optical impurity atoms or
semiconductor quantum dots is considered. Using the generalized perturbation
reduction method, the nonlinear wave equation is reduced to the coupled
nonlinear Schr\""odinger equations. It is shown that the second-order
derivatives play a key role in the description of the process of formation of
the bound state of two breathers oscillating with the sum and the difference of
frequencies and wave numbers. The resonant, nonresonant and hybrid mechanisms
of the formation of the two-component nonlinear pulse -- the vector breather
are realized depending on the light and medium parameters. Explicit analytical
expressions for the profile and parameters of the nonlinear pulse are
presented. The conditions of the excitation of resonant, nonresonant and hybrid
nonlinear waves are discussed. In the particular case, the resonant vector
breather coincides with the vector $0\pi$ pulse of self-induced transparency.",2004.10688v1
2017-10-16,Using gravitational-wave data to constrain dynamical tides in neutron star binaries,"We discuss the role of dynamical tidal effects for inspiralling neutron star
binaries, focussing on features that may be considered ""unmodelled"" in
gravitational-wave searches. In order to cover the range of possibilities, we
consider i) individual oscillation modes becoming resonant with the tide, ii)
the elliptical instability, where a pair of inertial modes exhibit a nonlinear
resonance with the tide, and iii) the non-resonant p-g instability which may
arise as high order p- and g-modes in the star couple nonlinearly to the tide.
In each case, we estimate the amount of additional energy loss that needs to be
associated with the dynamical tide in order for the effect to impact on an
observed gravitational-wave signal. We explore to what extent the involved
neutron star physics may be considered known and how one may be able to use
observational data to constrain theory.",1710.05950v1
2019-05-29,Atmospheric bistability and abrupt transitions to superrotation: wave-jet resonance and Hadley cell feedbacks,"Strong eastward jets at the equator have been observed in many planetary
atmospheres and simulated in numerical models of varying complexity. However,
the nature of the transition from a conventional state of the general
circulation, with easterlies or weak westerlies in the tropics, to such a
superrotating state remains unclear. Is it abrupt or continuous? This question
may have far-reaching consequences, as it may provide a mechanism for abrupt
climate change in a planetary atmosphere, both through the loss of stability of
the conventional circulation and through potential noise-induced transitions in
the bistability range. We study two feedbacks which may lead to bistability
between a conventional and a superrotating state: the Hadley cell feedback and
a wave-jet resonance feedback. We delineate the regime of applicability of
these two mechanisms in a simple model of zonal acceleration budget at the
equator. Then, we show using numerical simulations of the axisymmetric
primitive equations that the wave-jet resonance feedback indeed leads to robust
bistability, while the bistability governed by the Hadley cell feedback,
although observed in our numerical simulations, is much more fragile in a
multilevel model.",1905.12401v1
2021-08-12,Resonant field enhancement in lossy periodic structures supporting complex bound states in the continuum,"Resonant modes in a lossy periodic structure sandwiched between two lossless
homogeneous media form bands that depend on the Bloch wavevector continuously
and have a complex frequency due to radiation and absorption losses. A complex
bound state in the continuum (cBIC) is a special state with a zero radiation
loss in such a band. Plane waves incident upon the periodic structure induce
local fields that are resonantly enhanced. In this paper, we derive a rigorous
formula for field enhancement, and analyze its dependence on the frequency,
wavevector and amplitude of the incident wave. For resonances with multiple
radiation channels, we determine the incident wave that maximizes the field
enhancement, and find conditions under which the field enhancement can be
related to the radiation and dissipation quality factors. We also show that
with respect to the Bloch wavevector, the largest field enhancement is obtained
approximately when the radiation and dissipation quality factors are equal. Our
study clarifies the various factors related to field enhancement, and provides
a useful guideline for applications where a strong local field is important.",2108.05501v1
2019-04-26,Spectral and temporal modulations of femtosecond SPP wave packets induced by resonant transmission/reflection interactions with metal-insulator-metal nanocavities,"To study the dynamical optical interactions of nano-scaled
metal-insulator-metal (MIM) structures in temporal-frequency domain,
femtosecond surface plasmon polariton (SPP) wave packets propagate over a
surface with a MIM structure. The resonance nature of the SPP-cavity
interaction is reflected as strong modulations in the spectra of transmitted
and reflected SPP wavepackets, which show peaks and valleys, respectively,
corresponding to the MIM cavity's eigenmode. These features indicate that the
MIM structure acts as a Fabry-Perot etalon-type spectrum filter. With
appropriate tuning of the resonance frequency of the cavity, one can extract a
wave packet with a narrower time duration and temporally shifted intensity
peak.",1904.11750v1
2021-01-11,Timing and energy stability of resonant dispersive wave emission in gas-filled hollow-core waveguides,"We numerically investigate the energy and arrival-time noise of ultrashort
laser pulses produced via resonant dispersive wave emission in gas-filled
hollow-core waveguides under the influence of pump-laser instability. We find
that for low pump energy, fluctuations in the pump energy are strongly
amplified. However, when the generation process is saturated, the energy of the
resonant dispersive wave can be significantly less noisy than that of the pump
pulse. This holds for a variety of generation conditions and while still
producing few-femtosecond pulses. We further find that the arrival-time jitter
of the generated pulse remains well below one femtosecond even for a
conservative estimate of the pump pulse energy noise, and that photoionisation
and plasma dynamics can lead to exceptional stability for some generation
conditions. By applying our analysis to a scaled-down system, we demonstrate
that our results hold for frequency conversion schemes based on both small-core
microstructured fibre and large-core hollow capillary fibre.",2101.04014v2
2021-01-13,Modified rigorous coupled-wave analysis for grating-based plasmonic structures with delta-thin conductive channel. Far- and near-field study,"The modified rigorous coupled-wave analysis technique is developed to
describe the optical characteristics of the plasmonic structures with the
grating-gated delta-thin conductive channel in the far- and near-field zones of
electromagnetic waves. The technique was applied for analysis of the resonant
properties of AlGaN/GaN heterostructures combined with deeply-subwavelength
metallic grating which facilitates the excitation of the two-dimensional
plasmons in the THz frequency range. The convergence of the calculations at the
frequencies near the plasmon resonances is discussed. The impact of the
grating's parameters, including filling factor and thickness of the grating, on
resonant absorption of the structure was investigated in details. The spatial
distributions of electromagnetic field in a near-field zone were used for the
evaluation of total absorption of the plasmonic structures separating
contributions of the grating-gated two-dimensional electron gas and the grating
coupler.",2101.05002v1
2021-11-06,"On Fresnel-Airy Equations, Fabry-Perot Resonances and Surface Electromagnetic Waves in Arbitrary Bianisotropic Metamaterials, including with Multi-Hyperbolic Fresnel Wave Surfaces","We introduce a theory of optical responses of bianisotropic layers with
arbitrary effective medium parameters, which results in generalized
Fresnel-Airy equations for reflection and transmission coefficients at all
incidence directions and polarizations. The poles of these equations provide
explicit expressions for the dispersion of Fabry-Perot resonances and surface
electromatic waves in bianisotropic layers and interfaces. The existence
conditions of these resonances are topologically related to the zeros of the
high-k characteristic function h(k)=0 of bulk bianisotropic materials and
Durach et al. taxonomy of bianisotropic media according to the hyperbolic
topological classes [Applied Sciences, 10(3), 763 (2020); Optics
Communications, 476, 126349 (2020)].",2111.03791v1
2022-01-13,Mode conversion and laser energy absorption by plasma under an inhomogeneous external magnetic field,"The interaction of a high-frequency laser with plasma in the presence of an
inhomogeneous external magnetic field has been studied here with the help of
Particle-In-Cell simulation. It has been shown that laser enters inside the
plasma as an extraordinary wave (X-wave), where the electric field of the wave
oscillates perpendicular to both external magnetic field and propagation
direction, and as it travels through the plasma, its dispersion property
changes due to the inhomogeneity of the externally applied magnetic field. Our
study shows that the X-wave's electromagnetic energy is converted to an
electrostatic mode as it encounters the upper-hybrid (UH) resonance layer. In
the later stage of the evolution, this electrostatic wave breaks and converts
its energy to electron kinetic energy. Our study reveals two additional
processes involved in decaying electrostatic mode at the UH resonance layer. We
have shown that the energy of the electrostatic mode also converts to a
low-frequency lower-hybrid mode and high-frequency electromagnetic harmonic
radiations at the resonance layer. The dependence of energy conversion
processes on the gradient of external magnetic field has also been studied and
analyzed.",2201.04926v1
2022-01-22,Mode conversion and resonant absorption in inhomogeneous materials with flat bands,"Mode conversion of transverse electromagnetic waves into longitudinal
oscillations and the associated resonant absorption of wave energy in
inhomogeneous plasmas is a phenomenon that has been studied extensively in
plasma physics. We show that precisely analogous phenomena occur generically in
electronic and photonic systems where dispersionless flat bands and dispersive
bands coexist in the presence of an inhomogeneous potential or medium
parameter. We demonstrate that the systems described by the pseudospin-1 Dirac
equation with two dispersive bands and one flat band display mode conversion
and resonant absorption in a very similar manner to $p$-polarized
electromagnetic waves in an unmagnetized plasma by calculating the mode
conversion coefficient explicitly using the invariant imbedding method. We also
show that a similar mode conversion process takes place in many other systems
with a flat band such as pseudospin-2 Dirac systems, continuum models obtained
for one-dimensional stub and sawtooth lattices, and two-dimensional electron
systems with a quadratic band and a nearly flat band. We discuss some
experimental implications of mode conversion in flat-band materials and
metamaterials.",2201.08947v1
2022-10-24,The spiral arms of galaxies,"The most important theory of the spiral arms of galaxies is the density wave
theory based on the Lin-Shu dispersion relation. However, the density waves
move with the group velocity towards the inner Lindblad resonance and tend to
disappear. Various mechanisms to replenish the spiral waves have been proposed.
Nonlinear effects play an important role near the inner and outer Lindblad
resonances and corotation. The orbits supporting the spiral arms are precessing
ellipses in normal galaxies that extend up to the 4/1 resonance. On the other
hand, in barred galaxies the spiral arms extend along the manifolds of the
unstable periodic orbits at the ends of the bar and they are composed of
chaotic orbits. However these chaotic orbits can be found analytically.",2210.13632v1
2023-05-25,"$Z_{cs}$, $Z_c$ and $Z_b$ states under the complex scaling method","We investigate the $Z_b$, $Z_c$ and $Z_{cs}$ states within the chiral
effective field theory framework and the $S$-wave single channel molecule
picture. With the complex scaling method, we accurately solve the Schr\""odinger
equation in momentum space. Our analysis reveals that the $Z_b(10610)$,
$Z_b(10650)$, $Z_c(3900)$ and $Z_c(4020)$ states are the resonances composed of
the $S-$wave $(B\bar{B}^{*}+B^{*}\bar{B})/\sqrt{2}$, $B^{*}\bar{B}^*$,
$(D\bar{D}^{*}+D^{*}\bar{D})/\sqrt{2}$ and $D^{*}\bar{D}^*$, respectively.
Furthermore, although the $Z_{cs}(3985)$ and $Z_{cs}(4000)$ states exhibit a
significant difference in width, these two resonances may originate from the
same channel, the $S-$wave $(D_{s}\bar{D}^{*}+D_{s}^{*}\bar{D})/\sqrt{2}$.
Additionally, we find two resonances in the $S-$wave $D_s^*\bar{D}^*$ channel,
corresponding to the $Z_{cs}(4123)$ and $Z_{cs}(4220)$ states that await
experimental confirmation.",2305.15787v2
2023-07-11,Can the gravitational wave background feel wiggles in spacetime?,"Recently the international pulsar timing array collaboration has announced
the first strong evidence for an isotropic gravitational wave background (GWB).
We propose that rapid small oscillations (wiggles) in the Hubble parameter
would trigger a resonance with the propagating gravitational waves, leaving
novel signature in the GWB spectrum in the form of sharp resonance peaks. The
proposed signal can appear at all frequency ranges and is common to continuous
spectrum GWBs with arbitrary origin. Due to its resonant nature, the signal
strength differs by a perturbation order depending on whether the GWB is
primordial or not, which makes it a smoking gun for the primordial origin of
the observed GWB. We show that a large part of the parameter space of such
signal can be constrained by near future PTA observations, while fitting the
signal template to the current NanoGrav 15yr data already hints an interesting
feature near 15 nHz.",2307.05455v3
2023-07-11,Thin-Film Lithium Niobate Acoustic Resonator with High Q of 237 and k2 of 5.1% at 50.74 GHz,"This work reports a 50.74 GHz lithium niobate (LiNbO3) acoustic resonator
with a high quality factor (Q) of 237 and an electromechanical coupling (k2) of
5.17% resulting in a figure of merit (FoM, Q x k2) of 12.2. The LiNbO3
resonator employs a novel bilayer periodically poled piezoelectric film (P3F)
128 Y-cut LiNbO3 on amorphous silicon (a-Si) on sapphire stack to achieve low
losses and high coupling at millimeter wave (mm-wave). The device also shows a
Q of 159, k2 of 65.06%, and FoM of 103.4 for the 16.99 GHz tone. This result
shows promising prospects of P3F LiNbO3 towards mm-wave front-end filters.",2307.05742v1
2023-09-06,Is the NANOGrav detection evidence of resonant particle creation during inflation?,"We show that the recently reported cosmic gravitational wave background by
the NANOGrav 15-year collaboration may be the result of resonant particle
creation during inflation. For the appropriate amplitude and particle mass an
enhancement of the primordial scalar power spectrum could induce Secondary
Induced Gravitational Waves (SIGW) which will appear on a scale corresponding
to the frequency of the NANOGrav detection. Since the resonant creation will
have an effect comparable to that of a delta function increment as studied by
the NANOGrav 15-year collaboration, our study indicates that the low-frequency
Pulsar Timing Array (PTA) data could reveal the aspects of the physics during
inflation through the detection of a cosmic background of Gravitational Waves
(GW).",2309.03101v2
2023-09-10,Resonant excitation of vortex gyrotropic mode via surface acoustic waves,"Finding new energy-efficient methods for exciting magnetization dynamics is
one of the key challenges in magnonics. In this work, we present an approach to
excite the gyrotropic dynamics of magnetic vortices through the phenomenon of
inverse magnetostriction, also known as the Villari effect. We develop an
analytical model based on the Thiele formalism that describes the gyrotropic
motion of the vortex core including the energy contributions due to inverse
magnetostriction. Based on this model, we predict excitations of the vortex
core resonances by surface acoustic waves whose frequency is resonant with the
frequency of the vortex core. We verify the model's prediction using
micromagnetic simulations, and show the dependence of the vortex core's
oscillation radius on the surface acoustic wave amplitude and the static bias
field. Our study contributes to the advancement of energy-efficient magnetic
excitations by relying on voltage-induced driven dynamics, which is an
alternative to conventional current-induced excitations.",2309.04987v1
2023-09-18,Gravitational Wave Resonance in Ultra-Light Dark Matter Halos,"Ultra-Light Dark Matter (ULDM) halos constituted by Ultra-Light Axions (ULAs)
generate gravitational potentials that oscillate in time. In this paper I show
these potentials interact with gravitational waves, resonantly amplifying them.
For all ULA masses considered, the resonance in the solar region is currently
negligible, while in a denser dark matter environment, which may arise in
different scenarios, it might become significant. The frequency of the
amplified gravitational wave is equal to the ULA mass in the case of first
resonance band, which represents the most efficient scenario.",2309.09946v2
2023-10-23,Anisotropies in Scalar-Induced Gravitational-Wave Background from Inflaton-Curvaton Mixed Scenario with Sound Speed Resonance,"We propose a new model to generate large anisotropies in the scalar-induced
gravitational wave (SIGW) background via sound speed resonance in the
inflaton-curvaton mixed scenario. Cosmological curvature perturbations are not
only exponentially amplified at a resonant frequency, but also preserve
significant non-Gaussianity of local type described by $f_{\mathrm{nl}}$.
Besides a significant enhancement of energy-density fraction spectrum, large
anisotropies in SIGWs can be generated, because of super-horizon modulations of
the energy density due to existence of primordial non-Gaussianity. A reduced
angular power spectrum $\tilde{C}_{\ell}$ could reach an amplitude of
$[\ell(\ell+1)\tilde{C}_{\ell}]^{1/2} \sim 10^{-2}$, leading to potential
measurements via planned gravitational-wave detectors such as DECIGO. The large
anisotropies in SIGWs would serve as a powerful probe of the early universe,
shedding new light on the inflationary dynamics, primordial non-Gaussianity,
and primordial black hole dark matter.",2310.14606v3
2023-10-31,Analysis to closed surface-wave photonic crystal waveguides based on coupled-resonator optical waveguide theory,"Traditionally, one can construct a waveguide by introduce defects into
surface-wave photonic crystals (SPCs). Here we propose a new structure named
closed SPC that can introduce waveguide modes out of photonic bandgap of
surface-wave photonic crystal. In this paper, we have comprehensively analyzed
dispersion relation, group velocity, normalized transmission and electric field
distribution of closed SPC waveguides, and propose several methods to improve
performance of the waveguide based on coupled-resonator optical waveguide
theory. These methods can improve transmission efficiency from 10% to 60% and
eliminate intraband oscillation by adjusting eigenfrequency and coupling factor
. These methods are applicable to both single mode and multi mode situations.
This letter also paves a new way for improving the performance of other
coupled-resonator waveguides.",2310.20298v1
2024-01-23,28 THz soliton frequency comb in a continuous-wave pumped fiber Fabry-Perot resonator,"We report the generation of an optical frequency comb featuring 28 THz
bandwidth, sustained by a single 80 fs cavity soliton recirculating in a fiber
Fabry-Perot resonator. This large spectrum is comparable to frequency combs
obtained with microresonators operating in the anomalous dispersion regime.
Thanks to the compact design and the easy coupling of the resonator, cavity
solitons can be generated in an all-fiber experimental setup with a continuous
wave pumping scheme. We also observe the generation of a dispersive wave at
higher frequencies which is supported by higher-order dispersion. These
observations align remarkably well with both numerical simulations and the
established theory of cavity solitons.",2401.12858v1
2024-02-29,Transformation and amplification of light in optical waveguides and resonators modulated by a low frequency traveling wave,"We investigate the transformation and amplification of a light wave with
phase velocity $v$ and frequency $\omega$ propagating through an optical
waveguide and a racetrack resonator parametrically modulated by a travelling
wave with phase velocity $v_p$ and frequency $\omega_p \ll \omega$. We consider
the propagation within a small bandwidth $\Delta\omega \ll \omega$ where the
waveguide is assumed to be dispersionless and low loss. Close to the luminal
condition, $v_p=v$, the bandwidth of the output frequency comb spectrum, as
well as the propagation nonreciprocity, can significantly grow. However, for
realistic low-loss optical waveguides and resonators, the light amplification
remains small due to its essentially broadband character. For a lithium niobate
waveguide modulated with a $0.1\%$ relative refractive index amplitude at
frequency $\omega_p \sim 100$ GHz, the amplification of the light power
integrated over the frequency band $\Delta\omega \ll \omega \sim 200$ THz is
estimated as $\sim 1$ dB/m.",2402.19117v1
2008-12-23,Recoil velocity at 2PN order for spinning black hole binaries,"We compute the flux of linear momentum carried by gravitational waves emitted
from spinning binary black holes at 2PN order for generic orbits. In particular
we provide explicit expressions of three new types of terms, namely
next-to-leading order spin-orbit terms at 1.5 PN order, spin-orbit tail terms
at 2PN order, and spin-spin terms at 2PN order. Restricting ourselves to
quasi-circular orbits, we integrate the linear momentum flux over time to
obtain the recoil velocity as function of orbital frequency. We find that in
the so-called superkick configuration the higher-order spin corrections can
increase the recoil velocity up to about a factor 3 with respect to the
leading-order PN prediction. Furthermore, we provide expressions valid for
generic orbits, and accurate at 2PN order, for the energy and angular momentum
carried by gravitational waves emitted from spinning binary black holes.
Specializing to quasi-circular orbits we compute the spin-spin terms at 2PN
order in the expression for the evolution of the orbital frequency and found
agreement with Mik\'oczi, Vas\'uth and Gergely. We also verified that in the
limit of extreme mass ratio our expressions for the energy and angular momentum
fluxes match the ones of Tagoshi, Shibata, Tanaka and Sasaki obtained in the
context of black hole perturbation theory.",0812.4413v2
2012-02-03,Prototype effective-one-body model for nonprecessing spinning inspiral-merger-ringdown waveforms,"We first use five non-spinning and two mildly spinning (chi_i \simeq -0.44,
+0.44) numerical-relativity waveforms of black-hole binaries and calibrate an
effective-one-body (EOB) model for non-precessing spinning binaries, notably
its dynamics and the dominant (2,2) gravitational-wave mode. Then, we combine
the above results with recent outcomes of small-mass-ratio simulations produced
by the Teukolsky equation and build a prototype EOB model for detection
purposes, which is capable of generating inspiral-merger-ringdown waveforms for
non-precessing spinning black-hole binaries with any mass ratio and individual
black-hole spins -1 \leq chi_i \lesssim 0.7. We compare the prototype EOB model
to two equal-mass highly spinning numerical-relativity waveforms of black holes
with spins chi_i = -0.95, +0.97, which were not available at the time the EOB
model was calibrated. In the case of Advanced LIGO we find that the mismatch
between prototype-EOB and numerical-relativity waveforms is always smaller than
0.003 for total mass 20-200 M_\odot, the mismatch being computed by maximizing
only over the initial phase and time. To successfully generate merger waveforms
for individual black-hole spins chi_i \gtrsim 0.7, the prototype-EOB model
needs to be improved by (i) better modeling the plunge dynamics and (ii)
including higher-order PN spin terms in the gravitational-wave modes and
radiation-reaction force.",1202.0790v2
2013-06-10,Testing the validity of the single-spin approximation in inspiral-merger-ringdown waveforms,"Gravitational-wave signals from black-hole binaries with non-precessing spins
are described by four parameters -- each black hole's mass and spin. It has
been shown that the dominant spin effects can be modeled by a \emph{single}
spin parameter, leading to the development of several \emph{three-parameter}
waveform models. Previous studies indicate that these models should be adequate
for gravitational-wave detection. In this paper we focus on the systematic
biases that would result from using them to estimate binary parameters, and
consider a one-parameter family of configurations at one choice of mass ratio
and effective single spin. We find that for low-mass binaries within that
family of configurations, where the observable waveform is dominated by the
inspiral, the systematic bias in all physical parameters is smaller than the
parameter uncertainty due to degeneracies between the mass ratio and the spins,
at least up to signal-to-noise ratios (SNRs) of 50. For higher-mass binaries,
where the merger and ringdown make a greater contribution to the observed
signal, the bias in the mass ratio is comparable to its uncertainty at SNRs of
only $\sim$30, and the bias in the measurement of the total spin is
\emph{larger} than the uncertainty defined by the 90% confidence region even at
an SNR of only 10. Although this bias may be mitigated in future models by a
better choice of single-effective-spin parameter, these results suggest that it
may be possible to accurately measure \emph{both} black-hole spins in
intermediate-mass binaries.",1306.2320v1
2015-12-07,An anisotropic spin model of strong spin-orbit-coupled triangular antiferromagnets,"Motivated by the recent experimental progress on the strong
spin-orbit-coupled rare earth triangular antiferromagnet, we analyze the highly
anisotropic spin model that describes the interaction between the
spin-orbit-entangled Kramers' doublet local moments on the triangular lattice.
We apply the Luttinger-Tisza method, the classical Monte Carlo simulation, and
the self-consistent spin wave theory to analyze the anisotropic spin
Hamiltonian. The classical phase diagram includes the 120-degree state and two
distinct stripe ordered phases. The frustration is very strong and
significantly suppresses the ordering temperature in the regimes close to the
phase boundary between two ordered phases. Going beyond the semiclassical
analysis, we include the quantum fluctuations of the spin moments within a
self-consistent Dyson-Maleev spin-wave treatment. We find that the strong
quantum fluctuations melt the magnetic order in the frustrated regions. We
explore the magnetic excitations in the three different ordered phases as well
as in strong magnetic fields. Our results provide a guidance for the future
theoretical study of the generic model and are broadly relevant for strong
spin-orbit-coupled triangular antiferromagnets such as YbMgGaO4, RCd3P3,
RZn3P3, RCd3As3, RZn3As3, and R2O2CO3.",1512.02151v3
2016-09-20,Efficiency of nonspinning templates in gravitational wave searches for aligned-spin binary black holes,"We study the efficiency of nonspinning waveform templates in gravitational
wave searches for aligned-spin binary black holes (BBHs). We use PhenomD, which
is the most recent phenomenological waveform model designed to generate the
full inspiral-merger-ringdown waveforms emitted from BBHs with the spins
aligned with the orbital angular momentum. Here, we treat the effect of
aligned-spins with a single spin parameter $\chi$. We consider the BBH signals
with moderately small spins in the range of $-0.4\leq \chi \leq 0.4$. Using
nonspinning templates, we calculate fitting factors of the aligned-spin signals
in a wide mass range up to $\sim 100 M_{\odot}$. We find that the signals with
negative spins can have higher fitting factors than those with positive spins.
If $\chi = 0.3$, only the highly asymmetric-mass signals can have the fitting
factors exceeding the threshold of 0.965, while the fitting factors for all of
the signals can be larger than the threshold if $\chi = -0.3$. We demonstrate
that the discrepancy between the regions of a positive and a negative spins is
due to the physical boundary ($\eta \leq 0.25$) of the template parameter
space. We also show that the recovered mass parameters can be significantly
biased from the true parameters. We examine the impact of the systematic bias
on the parameter estimation by comparing the bias with the statistical error.",1609.06039v2
2016-10-21,An electric-field representation of the harmonic XY model,"The two-dimensional harmonic XY (HXY) model is a spin model in which the
classical spins interact via a piecewise parabolic potential. We argue that the
HXY model should be regarded as the canonical classical lattice spin model of
phase fluctuations in two-dimensional condensates, as it is the simplest model
that guarantees the modular symmetry of the experimental systems. Here we
formulate a lattice electric-field representation of the HXY model and contrast
this with an analogous representation of the Villain model and the
two-dimensional Coulomb gas with a purely rotational auxiliary field. We find
that the HXY model is a spin-model analogue of a lattice electric-field model
of the Coulomb gas with an auxiliary field, but with a temperature-dependent
vacuum (electric) permittivity that encodes the coupling of the spin vortices
to their background spin-wave medium. The spin vortices map to the Coulomb
charges, while the spin-wave fluctuations correspond to auxiliary-field
fluctuations. The coupling explains the striking differences in the
high-temperature asymptotes of the specific heats of the HXY model and the
Coulomb gas with an auxiliary field. Our results elucidate the propagation of
effective long-range interactions throughout the HXY model (whose interactions
are purely local) by the lattice electric fields. They also imply that global
spin-twist excitations (topological-sector fluctuations) generated by local
spin dynamics are ergodically excluded in the low-temperature phase. We discuss
the relevance of these results to condensate physics.",1610.06692v2
2017-12-08,Numerical Relativity Simulations of Precessing Binary Neutron Star Mergers,"We present the first set of numerical relativity simulations of binary
neutron mergers that include spin precession effects and are evolved with
multiple resolutions. Our simulations employ consistent initial data in general
relativity with different spin configurations and dimensionless spin magnitudes
$\sim 0.1$. They start at a gravitational-wave frequency of $\sim392$~Hz and
cover more than $1$ precession period and about 15 orbits up to merger. We
discuss the spin precession dynamics by analyzing coordinate trajectories,
quasi-local spin measurements, and energetics, by comparing spin aligned,
antialigned, and irrotational configurations. Gravitational waveforms from
different spin configuration are compared by calculating the mismatch between
pairs of waveforms in the late inspiral. We find that precession effects are
not distinguishable from nonprecessing configurations with aligned spins for
approximately face-on binaries, while the latter are distinguishable from a
nonspinning configurations. Spin precession effects are instead clearly visible
for approximately edge-on binaries.
  For the parameters considered here, precession does not significantly affect
the characteristic postmerger gravitational-wave frequencies nor the mass
ejection. Our results pave the way for the modeling of spin precession effects
in the gravitational waveform from binary neutron star events.",1712.02992v1
2020-04-09,Massive Spinning Bosons on the Celestial Sphere,"A natural extension of the Pasterski-Shao-Strominger (PSS) prescription is
described, enabling the map of Minkowski space amplitudes with massive spinning
external legs to the celestial sphere to be performed. An integral
representation for the conformal primary wave function (CPW) of massive
spinning bosons on the celestial sphere is derived explicitly for spin-one and
-two. By analogy with the spin-zero case, the spinning bulk-to-boundary
propagator on Euclidean AdS is employed to extend the massive CPW integral
representation to arbitrary integer spin, and to describe the appropriate
inverse transform of massive spinning CPWs back to the plane wave basis in
Minkowski space. Subsequently, a massive spin-$s$ momentum operator
representation on the celestial sphere is determined, and used in conjunction
with known Lorentz generators to derive Poincar\'e symmetry constraints on
generic massive spinning two-, three- and four-point celestial amplitude
structures. Finally, as a consistency check, three-point Minkowski space
amplitudes of two massless scalars and a spin-one or -two massive boson are
explicitly mapped to the celestial sphere, and the resulting three-point
function coefficients are confirmed to be in exact agreement with the results
obtained from Poincar\'e symmetry constraints.",2004.04309v2
2017-02-14,Quantum spin liquid and magnetic order in a two-dimensional non-symmorphic lattice: considering the distorted Kagome lattice of Volborthite,"The Kagome-lattice-based material, Volborthite, $\mathrm{Cu_3 V_2 O_7 (OH)_2
\cdot 2 H_2 O}$, has been considered as a promising platform for discovery of
unusual quantum ground states due to the frustrated nature of spin
interactions. Here we explore possible quantum spin liquid and magnetically
ordered phases in a two-dimensional non-symmorphic lattice described by $p2gg$
layer space group, which is consistent with the spatial anisotropy of the spin
model derived from density functional theory (DFT) for Volborthite. Using the
projective symmetry group (PSG) analysis and Schwinger boson mean field theory,
we classify possible spin liquid phases with bosonic spinons and investigate
magnetically ordered phases connected to such states. It is shown, in general,
that only translationally invariant mean field states are allowed in
two-dimensional non-symmorphic lattices, which simplifies the classification
considerably. The mean field phase diagram of the DFT-derived spin model is
studied and it is found that possible quantum spin liquid phases are connected
to two types of magnetically ordered phases, a coplanar incommensurate $(q,0)$
spiral order as the ground state and a closely competing coplanar commensurate
$(\pi,\pi)$ spin density wave order. In addition, periodicity enhancement of
the two-spinon continuum, a signature of symmetry fractionalization, is found
in the spin liquid phases connected to the $(\pi,\pi)$ spin density wave order.
We discuss relevance of these results to recent and future experiments on
Volborthite.",1702.04360v2
2016-11-22,Gravitational waves and mass ejecta from binary neutron star mergers: Effect of the stars' rotation,"We present new (3+1) dimensional numerical relativity simulations of the
binary neutron star (BNS) mergers that take into account the NS spins. We
consider different spin configurations, aligned or antialigned to the orbital
angular momentum, for equal and unequal mass BNS and for two equations of
state. All the simulations employ quasiequilibrium circular initial data in the
constant rotational velocity approach, i.e. they are consistent with Einstein
equations and in hydrodynamical equilibrium. We study the NS rotation effect on
the energetics, the gravitational waves (GWs) and on the possible
electromagnetic (EM) emission associated to dynamical mass ejecta. For
dimensionless spin magnitudes of $\chi\sim0.1$ we find that spin-orbit
interactions and also spin-induced-quadrupole deformations affect the
late-inspiral-merger dynamics. The latter is, however, dominated by finite-size
effects. Spin (tidal) effects contribute to GW phase differences up to 5 (20)
radians accumulated during the last eight orbits to merger. Similarly, after
merger the collapse time of the remnant and the GW spectrogram are affected by
the NSs rotation. Spin effects in dynamical ejecta are clearly observed in
unequal mass systems in which mass ejection originates from the tidal tail of
the companion. Consequently kilonovae and other EM counterparts are affected by
spins. We find that spin aligned to the orbital angular momentum leads to
brighter EM counterparts than antialigned spin with luminosities up to a factor
of two higher.",1611.07367v1
2017-04-12,Absorption and generation of femtosecond laser-pulse excited spin currents in non-collinear magnetic bilayers,"Spin currents can be generated on an ultrafast timescale by excitation of a
ferromagnetic (FM) thin film with a femtosecond laser-pulse. Recently, it has
been demonstrated that these ultrafast spin currents can transport angular
momentum to neighbouring FM layers, being able to change both the magnitude and
orientation of the magnetization in the adjacent layer. In this work, both the
generation and absorption of these optically excited spin currents are
investigated. This is done using non-collinear magnetic bilayers, i.e. two FM
layers separated by a conductive spacer. Spin currents are generated in a Co/Ni
multilayer with out-of-plane (OOP) anisotropy, and absorbed by a Co layer with
an in-plane (IP) anisotropy. This behaviour is confirmed by careful analysis of
the laser-pulse induced magnetization dynamics, whereafter it is demonstrated
that the transverse spin current is absorbed very locally near the injection
interface of the IP layer (90% within the first approx. 2 nm). Moreover, it
will also be shown that this local absorption results in the excitation of THz
standing spin waves within the IP layer. The dispersion measured for these high
frequency spin waves shows a discrepancy with respect to the theoretical
predictions, for which a first explanation involving intermixed interface
regions is proposed. Lastly, the spin current generation is investigated using
different number of repeats for the Co/Ni multilayer, which proves to be of
great relevance for identifying the optical spin current generation mechanism.",1704.03746v1
2022-04-25,Scattering phenomena for spin transport in Kitaev spin liquid,"The Kitaev model exhibits a canonical quantum spin liquid as a ground state
and hosts two fractional quasiparticles, itinerant Majorana fermion and
localized flux excitation. The former can carry heat and spin modulations in
the quantum spin liquid, but the role of the latter remains unknown for the
transport phenomena. Here, we focus on spin transport in the presence of
excited fluxes and report that they yield strong interference in the
propagation of the Majorana fermions, which feel gauge-like potential emergent
around the fluxes. We examine the transient spin dynamics triggered by a pulsed
magnetic field at an edge. In the absence of excited fluxes, the magnetic-field
pulse creates the plane wave of the Majorana fermions, which flows in the
quantum spin liquid. Although this wave does not accompany the change of local
spin moments in bulk, it induces local moments at the side opposite to the edge
under the magnetic-field pulse. We observe the spatial modulation of induced
spin moments when fluxes are excited in the bulk region. This behavior is more
striking than the case of lattice defects. Moreover, we find that, although the
amplitude of the spatial change is almost independent of the distance between
lattice defects, it is strongly enhanced by increasing the distance for the
case of excited fluxes. The difference is understood from the influence on the
itinerant Majorana fermions; the lattice defects change the system locally, but
flux excitations alter all the transfer integrals on the string connecting
them. The present results will provide another route to observing intrinsic
flux excitations distinguished from extrinsic effects such as lattice defects.",2204.11578v1
2022-06-01,Signatures of spin precession and nutation in isolated black-hole binaries,"The spin precession of binary black holes (BBHs) that originate from isolated
high-mass binary stars is determined by the interplay of phenomena such as
tides, winds, accretion, common-envelope evolution, natal kicks, and stellar
core-envelope coupling. In previous work, we identified regions of the
parameter space that may produce BBHs with large misalignments from natal kicks
and high spin magnitudes from three mechanisms - tides, accretion, or
inheritance via minimal core-envelope coupling. Here, we explore the spin
precession of such BBHs using five parameters that describe the amplitude and
frequency with which the orbital angular momentum precesses and nutates about
the total angular momentum, modulating the gravitational-wave emission.
Precession is generally possible for sufficiently strong natal kicks provided
at least one of the black holes is spinning. Nutation is a consequence of
spin-spin coupling and depends on the three spin-up mechanisms. Tidal
synchronization can leave a distinct correlation between the aligned effective
spin and the nutation frequency, but does not produce large nutations. When a
black hole accretes $\gtrsim 20\%$ of its companion's envelope, the precession
frequency and amplitude are large. A much smaller amount of accretion, e.g.,
$\approx 2\%$, is needed to provide a large precession frequency and amplitude
when the accretor is a Wolf-Rayet (WR) star. The inheritance of high natal WR
spins ($\gtrsim 5\%$ of their maximum breakup value) via minimal core-envelope
coupling is the most promising mechanism for producing nutating BBHs, implying
that a measurement of nutation from gravitational-wave observations may suggest
isolated-binary origin with minimal core-envelope coupling.",2206.00391v2
2023-01-18,Charged magnons on the surface of a topological insulator,"We study a system of two-dimensional Dirac electrons (as is realized on the
surface of a 3D topological insulator) coupled to an array of localized spins.
The spins are coupled ferromagnetically to each other, forming an ordered
ground state with low-energy spin-wave excitations (magnons). The Dirac
electrons couple to the spins through a spin-dependent effective Zeeman field.
The out-of-plane effective Zeeman field therefore serves as a Dirac mass that
gaps the electronic spectrum. Once a spin is flipped, it creates a surrounding
domain in which the sign of the Dirac mass is opposite to that of the rest of
the sample. Therefore, an electronic bound state appears on the domain wall, as
predicted by Jackiw and Rebbi. However, in a quantum magnet, a localized spin
flip does not produce an eigenstate. Instead, the eigenstates correspond to
delocalized spin waves (magnons). As in the case of the single flipped spin,
the delocalized magnon also binds an in-gap electronic state. We name this
excitation a `Jackiw-Rebbi-Magnon' (JRM) and study its signature in the dynamic
spin susceptibility. When the sample is tunnel-coupled to an electronic
reservoir, a magnon produced in a system without any electrons hybridizes with
a JRM (which binds a single electron), producing magnon-JRM polaritons. For
such a system, we identify a quantum phase transition when the magnon-JRM
polariton energy falls below that of the fully polarized ferromagnetic ground
state.",2301.07754v2
2003-01-11,Coherent transport of neutral atoms in spin-dependent optical lattice potentials,"We demonstrate the controlled coherent transport and splitting of atomic wave
packets in spin-dependent optical lattice potentials. Such experiments open
intriguing possibilities for quantum state engineering of many body states.
After first preparing localized atomic wave functions in an optical lattice
through a Mott insulating phase, we place each atom in a superposition of two
internal spin states. Then state selective optical potentials are used to split
the wave function of a single atom and transport the corresponding wave packets
in two opposite directions. Coherence between the wave packets of an atom
delocalized over up to 7 lattice sites is demonstrated.",0301169v1
1998-09-02,Group Theoretical Examination of the Relativistic Wave Equations on Curved Spaces. III. Real reducible spaces,"The group theoretical approach to the relativistic wave equations on the real
reducible spaces for spin~0, 1/2 and~1 massless particles is considered. The
invariant wave equations which determine the appropriate irreducible
representations are constructed. The coincidence of these equations with the
general-covariant Klein-Gordon, Weyl and Maxwell equations on the corresponding
spaces is shown. The explicit solutions of these equations possessing a
simplicity and physical transparency are obtained in the form of so-called
""plane waves"" without using the method of separation of variables. The
invariance properties of these ""plane waves"" for the spinless particles under
the group $SO(3,1)$ were used for the construction of the invariant spin~0,1/2
and~1 two-point functions on the $H^3$. Secondly quantized spin~0,1/2 and~1
fields on the ${\Bbb R}^{1}\otimes H^{3}$ are constructed; their propagators
which are their (anti)commutators in different points, are expressed in terms
of the mentioned two-point functions. From here the ${\Bbb R}^{1}\otimes
  SO(3,1)$-invariance follows.",9809011v1
2011-04-29,Tail-induced spin-orbit effect in the gravitational radiation of compact binaries,"Gravitational waves contain tail effects which are due to the back-scattering
of linear waves in the curved space-time geometry around the source. In this
paper we improve the knowledge and accuracy of the two-body inspiraling
post-Newtonian (PN) dynamics and gravitational-wave signal by computing the
spin-orbit terms induced by tail effects. Notably, we derive those terms at 3PN
order in the gravitational-wave energy flux, and 2.5PN and 3PN orders in the
wave polarizations. This is then used to derive the spin-orbit tail effects in
the phasing through 3PN order. Our results can be employed to carry out more
accurate comparisons with numerical-relativity simulations and to improve the
accuracy of analytical templates aimed at describing the whole process of
inspiral, merger and ringdown.",1104.5659v2
2014-03-06,A method for narrow-band searches of continuous gravitational wave signals,"Targeted searches of continuous waves from spinning neutron stars normally
assume that the frequency of the gravitational wave signal is at a given known
ratio with respect to the rotational frequency of the source, e.g. twice for an
asymmetric neutron star rotating around a principal axis of inertia. In fact
this assumption may well be invalid if, for instance, the gravitational wave
signal is due to a solid core rotating at a slightly different rate with
respect to the star crust. In this paper we present a method for {\it
narrow-band} searches of continuous gravitational wave signals from known
pulsars in the data of interferometric detectors. This method assumes source
position is known to high accuracy, while a small frequency and spin-down range
around the electromagnetic-inferred values is explored. Barycentric and
spin-down corrections are done with an efficient time-domain procedure.
Sensitivity and computational efficiency estimates are given and results of
tests done using simulated data are also discussed.",1403.1484v1
2017-07-04,Dirac electron in a chiral space-time crystal created by counterpropagating circularly polarized plane electromagnetic waves,"The family of solutions to the Dirac equation for an electron moving in an
electromagnetic lattice with the chiral structure created by counterpropagating
circularly polarized plane electromagnetic waves is obtained. At any nonzero
quasimomentum, the dispersion equation has two solutions which specify bispinor
wave functions describing electron states with different energies and mean
values of momentum and spin operators. The inversion of the quasimomentum
results in two other linearly independent solutions. These four basic wave
functions are uniquely defined by eight complex scalar functions (structural
functions), which serve as convenient building blocks of the relations
describing the electron properties. These properties are illustrated in
graphical form over a wide range of quasimomentums. The superpositions of two
basic wave functions describing different spin states and corresponding to (i)
the same quasimomentum (unidirectional electron states with the spin
precession) and (ii) the two equal-in-magnitude but oppositely directed
quasimomentums (bidirectional electron states) are also treated.",1707.01140v2
2016-03-21,Engineering chiral density waves and topological band structures by multiple-$Q$ superpositions of collinear up-up-down-down orders,"Magnetic orders characterized by multiple ordering vectors harbor
noncollinear and noncoplanar spin textures and can be a source of unusual
electronic properties through the spin Berry phase mechanism. We theoretically
show that such multiple-$Q$ states are stabilized in itinerant magnets in the
form of superpositions of collinear up-up-down-down (UUDD) spin states, which
accompany the density waves of vector and scalar chirality. The result is drawn
by examining the ground state of the Kondo lattice model with classical
localized moments, especially when the Fermi surface is tuned to be partially
nested by the symmetry-related commensurate vectors. We unveil the instability
toward the multiple-$Q$ UUDD states with chirality density waves, using the
perturbative theory, variational calculations, and large-scale Langevin
dynamics simulations. We also show that the chirality density waves can induce
rich nontrivial topology of electronic structures, such as the massless Dirac
semimetal, Chern insulator with quantized topological Hall response, and
peculiar edge states which depend on the phase of chirality density waves at
the edges.",1603.06646v1
2019-03-11,Wave Functions and Leptonic Decays of Bottom Mesons In the Relativistic Potential Model,"We study the wave functions and purely leptonic decays of $b$-flavored mesons
(pseudoscalars, vector mesons, and higher excited states that are well
established in experiment) in the relativistic potential model based on our
previous works. The wave functions are obtained by solving the wave equation
including the spin-spin and spin-orbit corrections in the effective potential.
The decay constants of $B$, $B^*$ and some of their excited states that have
been found in experiment are calculated with these wave functions. Then the
branching fractions of the purely leptonic decay modes of these bottom mesons
are studied. Our results are in well agreement with experiment data for decay
modes that have been measured in experiments. We also provide predictions for
some yet unmeasured channels, which are useful for experimental test in the
future.",1903.04295v1
2020-12-15,Propagation of polarized gravitational waves,"The propagation of high-frequency gravitational waves can be analyzed using
the geometrical optics approximation. In the case of large but finite
frequencies, the geometrical optics approximation is no longer accurate, and
polarization-dependent corrections at first order in wavelength modify the
propagation of gravitational waves via a spin-orbit coupling mechanism. We
present a covariant derivation from first principles of effective ray equations
describing the propagation of polarized gravitational waves, up to first-order
terms in wavelength, on arbitrary spacetime backgrounds. The effective ray
equations describe a gravitational spin Hall effect for gravitational waves and
are of the same form as those describing the gravitational spin Hall effect of
light, derived from Maxwell's equations.",2012.08363v1
2020-12-21,Inverse Faraday Effect in an Optomagnonic Waveguide,"Single-mode high-index-contrast waveguides have been ubiquitously exploited
in optical, microwave, and phononic structures for achieving enhanced
wave-matter interactions. Although micro-scale optomechanical and
electro-optical devices have been widely studied, optomagnonic devices remain a
grand challenge at the microscale. Here, we introduce a planar optomagnonic
waveguide platform based on a ferrimagnetic insulator that simultaneously
supports single transverse mode of spin waves (magnons) and highly confined
optical modes. The co-localization of spin and light waves gives rise to
enhanced inverse Faraday effect, and as a result, magnons are excited by an
effective magnetic field generated by interacting optical photons. Moreover,
the strongly enhanced optomagnonic interaction allows us to observe such effect
using low-power (milliwatt level) light signals in the continuous-wave form, as
opposed to high-intensity (megawatt peak power) light pulses that are typically
required in magnetic bulk materials or thin films. The optically-driven magnons
are detected electrically with preserved phase coherence, showing the
feasibility for launching spin waves with low-power continuous optical fields.",2012.11119v2
2022-12-14,Measuring neutron-star distances and properties with gravitational-wave parallax,"Gravitational-wave astronomy allows us to study objects and events invisible
to electromagnetic waves. So far, only signals triggered by coalescing binaries
have been detected. However, as the interferometers' sensitivities improve over
time, we expect to observe weaker signals in the future, e.g. emission of
continuous gravitational waves from spinning, isolated neutron stars. Parallax
is a well-known method, widely used in electromagnetic astronomical
observations, to estimate the distance to a source. In this work, we consider
the application of the parallax method to gravitational-wave searches and
explore possible distance estimation errors. We show that detection of parallax
in the signal from a spinning down source can constrain the neutron star moment
of inertia. For instance, we found that the relative error of the moment of
inertia estimation is smaller than $10\%$ for all sources closer than 300 pc,
for the assumed birth frequency of 700 Hz, ellipticity $\geq 10^{-7}$ and for
two years of observations by the Einstein Telescope, assuming spin down due
purely to quadrupolar gravitational radiation.",2212.07506v3
2023-10-16,Gravitational wave analogues in spin nematics and cold atoms,"Many large-scale phenomena in our Universe, such as gravitational waves, are
challenging to reproduce in laboratory settings. However, parallels with
condensed matter systems can provide alternative routes for experimental
accessibility. Here we show how spin nematic phases provide a low-energy avenue
for accessing the physics of linearized gravity, and in particular that their
Goldstone modes are relativistically-dispersing massless spin-2 excitations,
analogous to gravitational waves. We show at the level of the action that the
low-energy effective field theory describing a spin nematic is in
correspondence with that of linearized gravity. We then explicitly identify a
microscopic model of a spin-1 magnet whose excitations in the low energy limit
are relativistically dispersing, massless spin-2 Bosons which are in one-to-one
correspondence with gravitational waves and, supported by simulation, outline a
procedure for directly observing these analogue waves in a cold gas of
$^{23}$Na atoms.",2310.10078v1
2014-11-11,Magnonic Charge Pumping via Spin-Orbit Coupling,"The interplay between spin, charge, and orbital degrees of freedom has led to
the development of spintronic devices like spin-torque oscillators, spin-logic
devices, and spin-transfer torque magnetic random-access memories. In this
development spin pumping, the process where pure spin-currents are generated
from magnetisation precession, has proved to be a powerful method for probing
spin physics and magnetisation dynamics. The effect originates from direct
conversion of low energy quantised spin-waves in the magnet, known as magnons,
into a flow of spins from the precessing magnet to adjacent normal metal leads.
The spin-pumping phenomenon represents a convenient way to electrically detect
magnetisation dynamics, however, precessing magnets have been limited so far to
pump pure spin currents, which require a secondary spin-charge conversion
element such as heavy metals with large spin Hall angle or multi-layer layouts
to be detectable. Here, we report the experimental observation of charge
pumping in which a precessing ferromagnet pumps a charge current, demonstrating
direct conversion of magnons into high-frequency currents via the relativistic
spin-orbit interaction. The generated electric current, differently from spin
currents generated by spin-pumping, can be directly detected without the need
of any additional spin to charge conversion mechanism and amplitude and phase
information about the relativistic current-driven magnetisation dynamics. The
charge-pumping phenomenon is generic and gives a deeper understanding of the
recently observed spin-orbit torques, of which it is the reciprocal effect and
which currently attract interest for their potential in manipulating magnetic
information. Furthermore, charge pumping provides a novel link between
magnetism and electricity and may find application in sourcing alternating
electric currents.",1411.2779v1
2006-07-03,Persistent current generation by small polarons in a spin-density wave background,"Persistent current generation by small polarons embedded in a spin-density
wave background in a two dimensional lattice is theoretically studied. When the
embedded small polarons become cores of merons and antimerons (vortices in spin
configuration with winding numbers +1 and -1, respectively), a spin Berry phase
arises from the spiral spin texture of the merons and antimerons, and generates
a spin current around the polarons. Electric current is, however, absent due to
the exact cancellation of the up- and down-spin electron currents. By addition
of an imaginary magnetic flux that negates the fictitious magnetic flux from
the spin Berry phase, the state with merons and antimerons is stabilized and
non-zero electric current appears; this imaginary flux becomes a real one when
side-by-side bipolaronic cores of merons and antimerons are formed, where the
real flux arises spontaneously from the wave function for the motion of the
system as a whole; thus, the bipolarons serve as pumps for the persistent
electric current. It is also shown that a Nernst signal stems from thermal
diffusion of the bipolarons. Implications of the present results to anomalous
properties of cuprate superconductors, including the enhanced Nernst signal,
Drude peak, and Fermi arc are also discussed. The present result suggests the
appearance of the phase variable or ``Nambu-Goldstone'' mode for the
superconductivity without the breakdown of the global U(1) gauge invariance in
the cuprates.",0607033v1
2013-05-26,"Final spin and radiated energy in numerical simulations of binary black holes with equal masses and equal, aligned or anti-aligned spins","The behavior of merging black holes (including the emitted gravitational
waves and the properties of the remnant) can currently be computed only by
numerical simulations. This paper introduces ten numerical relativity
simulations of binary black holes with equal masses and equal spins aligned or
anti-aligned with the orbital angular momentum. The initial spin magnitudes
have $|\chi_i| \lesssim 0.95$ and are more concentrated in the aligned
direction because of the greater astrophysical interest of this case. We
combine this data with five previously reported simulations of the same
configuration, but with different spin magnitudes, including the highest spin
simulated to date, $\chi_i \approx 0.97$. This data set is sufficiently
accurate to enable us to offer improved analytic fitting formulae for the final
spin and for the energy radiated by gravitational waves as a function of
initial spin. The improved fitting formulae can help to improve our
understanding of the properties of binary black hole merger remnants and can be
used to enhance future approximate waveforms for gravitational wave searches,
such as Effective-One-Body waveforms.",1305.5991v2
2014-11-15,Cubic order spin effects in the dynamics and gravitational wave energy flux of compact object binaries,"We investigate cubic-in-spin effects for inspiralling compact objects
binaries, both in the dynamics and the energy flux emitted in gravitational
waves, at the leading post-Newtonian order. We use a Lagrangian formalism to
implement finite-size effects, and extend it at cubic order in the spins, which
corresponds to the octupolar order in a multipolar decomposition. This
formalism allows us to derive the equation of motion, equations of precession
for the spin, and stress-energy tensor of each body in covariant form, and
admits a formal generalization to any multipolar order. For spin-induced
multipoles, i.e. in the case where the rotation of the compact object is sole
responsible for the additional multipole moments, we find a unique structure
for the octupolar moment representing cubic-in-spin effects. We apply these
results to compute the associated effects in the dynamics of compact binary
systems, and deduce the corresponding terms in the energy loss rate due to
gravitational waves. These effects enter at the third-and-a-half post-Newtonian
order, and can be important for binaries involving rapidly spinning black
holes. We provide simplified results for spin-aligned, circular orbits, and
discuss the quantitative importance of the new contributions.",1411.4118v2
2021-12-10,"Observation and control of collective spin-wave mode-hybridisation in chevron arrays and square, staircase and brickwork artificial spin ices","Dipolar magnon-magnon coupling has long been predicted in nano-patterned
artificial spin systems. However, observation of such phenomena and related
collective spin-wave signatures have until recently proved elusive or limited
to low-power edge-modes which are difficult to measure experimentally. Here we
describe the requisite conditions for dipolar mode-hybridisation, how it may be
controlled, why it was not observed earlier and how strong coupling may occur
between nanomagnet bulk-modes. We experimentally investigate four
nano-patterned artificial spin system geometries: `chevron' arrays, `square',
`staircase' and `brickwork' artificial spin ices. We observe significant
dynamic dipolar-coupling in all systems with relative coupling strengths and
avoided-crossing gaps supported by micromagnetic-simulation results. We
demonstrate reconfigurable mode-hybridisation regimes in each system via
microstate control, and in doing so elucidate the underlying dynamics governing
dynamic dipolar-coupling with implications across reconfigurable magnonics. We
demonstrate that confinement of the bulk-modes via edge effects play a critical
role in dipolar hybridised-modes, and treating nanoislands as a coherently
precessing macro-spins or standing spin-waves are insufficient to capture
experimentally-observed coupling phenomena. Finally, we present a
parameter-space search detailing how coupling strength may be tuned via
nanofabrication-dimensions and material properties.",2112.05354v1
2023-09-04,Unconventional p-wave magnets,"The electronic structure of atoms is organized into even and odd-parity-wave
s, p, d, ... orbitals. An analogous classification of condensed matter phases
emerged with the discovery of conventional s-wave superconductivity in mercury,
followed by the discoveries of unconventional p-wave superfluidity in $^{3}$He
and unconventional d-wave superconductivity in cuprates. To date, the known
counterparts in magnetism have been the conventional ferromagnets with s-wave
spin polarization in the electronic structure, and the recently discovered
altermagnets[1-3] with unconventional d-wave and higher even-parity wave spin
polarization[1,2,4-7]. Here we identify the long-sought magnetic counterpart of
unconventional p-wave superfluidity[8,9] -- the unconventional magnet with
p-wave spin polarization[10,11]. We show that that collinear p-wave
spin-polarization arises in a coplanar spin-symmetry subset of a class of
noncentrosymmetric and noncolinear magnetic crystals with combined
time-reversal and lattice translation symmetry. Contrary to common
assumptions[12-15], we show that noncollinear magnets from this class
universally exhibit nonrelativistic spin splittings and that these odd-parity
wave spin splittings preserve time-reversal symmetry of the band structure. We
predict large spin splitings reaching 500 meV by first-principles calculations
and we identify 60 realistic material candidates. Inspired by the rich and
anisotropic properties of superfluid $^{3}$He[8,9] our result opens up a wide
range of possibilities to investigate unconventional p-wave order parameters in
crystals and their exploitation in spintronics and topological physics[16-21].",2309.01607v2
2001-10-22,Non-resonant nonlinear coupling of magnetohydrodynamic waves in inhomogeneous media,"A new mechanism for the enhanced generation of compressible fluctuations by
Alfven waves is presented. A strongly nonlinear regime of Alfven wave
phase-mixing is numerically simulated in a one-dimensionally inhomogeneous
plasma of finite temperature. It is found that the inhomogeneity of the medium
determines the efficiency of nonlinear excitation of magnetoacoustic waves. The
level of the compressible fluctuations is found to be higher (up to the factor
of two) in inhomogeneous regions. The amplitude of the generated
magnetoacoustic wave can reach up to 30% of the source Alfven wave amplitude,
and this value is practically independent of the Alfven wave amplitude and the
steepness of Alfven speed profile. The highest amplitudes of compressible
disturbances are reached in plasmas with beta of about 0.5. The further growth
of the amplitude of compressible fluctuations is depressed by saturation.",0110493v1
2004-01-28,Spiral wave drift in an electric field and scroll wave instabilities,"I present the numerical computation of speed and direction of the drift of a
spiral wave in an excitable medium in the presence of an electric field. In
contrast to earlier results, the drift speed presents a strong variation close
to the parameter value where the drift speed component along the field changes
direction. Using a simple phenomenological model and results from a numerical
linear stability analysis of scroll waves, I show this behavior can be
attributed to a resonance of the meander modes with the translation modes of
the spiral wave. Extending this phenomenological model to scroll waves also
clarifies the link between the drift and long wavelength instabilities of
scroll waves.",0401588v2
2005-07-21,One-band Hubbard model with hopping asymmetry and the effective theory at finite U: Phase diagram and metal-insulator transition,"We study the one-band Hubbard model at half filling with hopping asymmetry
and its effective model at finite but large U up to the second order of tmix/U.
Two variational wave functions, the resonating valence bond (RVB) wave function
and antiferromagnetic (AF) RVB coexisted wave function, are studied by
variational Monte Carlo method on L*L square lattices up to L=12. Based on
these two wave functions, the phase diagrams for both models are presented. For
the Hubbard model, we find that there is a metal-insulator transition when the
hopping parameter tmix which changes the local double occupant vanishes while
only a metal-insulator crossover is explored for any finite tmix. For the
effective model in which the perturbation expansion is up to the second order
of tmix/U, a clear metal-insulator transition can be identified for both
variational wave functions and the phase diagram can be drawn accordingly. In
both models, we find that the systems are dominated by AF-RVB wave function
when U is large while the RVB wave function is favored when U is small.",0507494v1
2003-07-05,Light cone nucleon wave function in the quark-soliton model,"The light-cone wave function of the nucleon is calculated in the limit
  N_c -> infinity in the quark-soliton model inspired by the theory of the
instanton vacuum of QCD. The technique of the finite time evolution operator is
used in order to derive expressions for all components of the Fock vector
describing the nucleon in the infinite momentum frame. It is shown that nucleon
wave function for large N_c can be expressed in terms of the wave function of
the discrete level in the self-consistent meson field and light cone wave
functions of 1,2, etc mesons. The 3-quark components of the nucleon and
Delta-resonance are estimated. Wave function of the nucleon appears to be
positive in the whole region of x and it has rather small asymmetry. It differs
strongly both from Chernyak-Zhitnitsky wave function and the asymptotic one.
Large momentum transfer asymptotic of the electromagnetic and axial form
factors is discussed.",0307077v2
2006-11-17,Laminated Wave Turbulence: Generic Algorithms II,"The model of laminated wave turbulence puts forth a novel computational
problem - construction of fast algorithms for finding exact solutions of
Diophantine equations in integers of order $10^{12}$ and more. The equations to
be solved in integers are resonant conditions for nonlinearly interacting waves
and their form is defined by the wave dispersion. It is established that for
the most common dispersion as an arbitrary function of a wave-vector length two
different generic algorithms are necessary: (1) one-class-case algorithm for
waves interacting through scales, and (2) two-class-case algorithm for waves
interacting through phases. In our previous paper we described the
one-class-case generic algorithm and in our present paper we present the
two-class-case generic algorithm.",0611042v1
2002-07-26,Landau damping of partially incoherent Langmuir waves,"It is shown that partial incoherence, in the form of stochastic phase noise,
of a Langmuir wave in an unmagnetized plasma gives rise to a Landau-type
damping. Starting from the Zakharov equations, which describe the nonlinear
interaction between Langmuir and ion-acoustic waves, a kinetic equation is
derived for the plasmons by introducing the Wigner-Moyal transform of the
complex Langmuir wave field. This equation is then used to analyze the
stability properties of small perturbations on a stationary solution consisting
of a constant amplitude wave with stochastic phase noise. The concomitant
dispersion relation exhibits the phenomenon of Landau-like damping. However,
this damping differs from the classical Landau damping in which a Langmuir
wave, interacting with the plasma electrons, loses energy. In the present
process, the damping is non-dissipative and is caused by the resonant
interaction between an instantaneously-produced disturbance, due to the
parametric interactions, and a partially incoherent Langmuir wave, which can be
considered as a quasi-particle composed of an ensemble of partially incoherent
plasmons.",0207050v1
2007-08-28,Resonantly damped surface and body MHD waves in a solar coronal slab with oblique propagation,"The theory of magnetohydrodynamic (MHD) waves in solar coronal slabs in a
zero-$\beta$ configuration and for parallel propagation of waves does not allow
the existence of surface waves. When oblique propagation of perturbations is
considered both surface and body waves are able to propagate. When the
perpendicular wave number is larger than a certain value, the body kink mode
becomes a surface wave. In addition, a sausage surface mode is found below the
internal cut-off frequency. When non-uniformity in the equilibrium is included,
surface and body modes are damped due to resonant absorption. In this paper,
first, a normal-mode analysis is performed and the period, the damping rate,
and the spatial structure of eigenfunctions are obtained. Then, the
time-dependent problem is solved, and the conditions under which one or the
other type of mode is excited are investigated.",0708.3783v1
2010-08-05,Linear and Non-Linear Landau Resonance of Kinetic Alfvén Waves: Consequences for Electron Distribution and Wave Spectrum in the Solar Wind,"Kinetic Alfven wave turbulence in solar wind is considered and it is shown
that non-Maxwellian electron distribution function has a significant effect on
the dynamics of the solar wind plasmas. Linear Landau damping leads to the
formation of a plateau in the parallel electron distribution function which
diminishes the Landau damping rate significantly. Nonlinear scattering of waves
by plasma particles is generalized to short wavelengths and it is found that
for the solar wind parameters this scattering is the dominant process as
compared to three wave decay and coalescence in the wave vector range .
Incorporation of these effects lead to the steepening of the wave spectrum
between the inertial and the dissipation ranges with a spectral index between 2
and 3. This region can be labeled as the scattering range. Such steepening has
been observed in the solar wind plasmas.",1008.0993v1
2011-04-14,Asymptotic Behavior of Massless Dirac Waves in Schwarzschild geometry,"In this paper, we show that massless Dirac waves in the Schwarzschild
geometry decay to zero at a rate $t^{-2\lambda}$, where $\lambda=1, 2,...$ is
the angular momentum. Our technique is to use Chandrasekhar's separation of
variables whereby the Dirac equations split into two sets of wave equations.
For the first set, we show that the wave decays as $t^{-2\lambda}$. For the
second set, in general, the solutions tend to some explicit profile at the rate
$t^{-2\lambda}$. The decay rate of solutions of Dirac equations is achieved by
showing that the coefficient of the explicit profile is exactly zero. The key
ingredients in the proof of the decay rate of solutions for the first set of
wave equations are an energy estimate used to show the absence of bound states
and zero energy resonance and the analysis of the spectral representation of
the solutions. The proof of asymptotic behavior for the solutions of the second
set of wave equations relies on careful analysis of the Green's functions for
time independent Schr\""odinger equations associated with these wave equations.",1104.2772v1
2012-08-02,Co-existence of Whistler Waves with Kinetic Alfven Wave Turbulence for the High-beta Solar Wind Plasma,"It is shown that the dispersion relation for whistler waves is identical for
a high or low beta plasma. Furthermore in the high-beta solar wind plasma
whistler waves meet the Landau resonance with electrons for velocities less
than the thermal speed, and consequently the electric force is small compared
to the mirror force. As whistlers propagate through the inhomogeneous solar
wind, the perpendicular wave number increases through refraction, increasing
the Landau damping rate. However, the whistlers can survive because the
background kinetic Alfven wave turbulence creates a plateau by quasilinear
diffusion in the solar wind electron distribution at small velocities. It is
found that for whistler energy density of only ~10^-3 that of the kinetic
Alfven waves, the quasilinear diffusion rate due to whistlers is comparable to
KAW. Thus very small amplitude whistler turbulence can have a significant
consequence on the evolution of the solar wind electron distribution function.",1208.0623v1
2014-10-28,Quantitative Relation between Modulational Instability and Several Well-known Nonlinear Excitations,"We study on the relations between modulational instability and several
well-known nonlinear excitations in a nonlinear fiber, such as bright soliton,
nonlinear continuous wave, Akhmediev breather, Peregrine rogue wave, and
Kuznetsov-Ma breather. We present a quantitative correspondence between them
based on the dominant frequency and propagation constant of each perturbation
on a continuous wave background. Especially, we find rogue wave comes from
modulational instability under the ""resonance"" perturbation with continuous
wave background. These results will deepen our understanding on rogue wave
excitation and could be helpful for controllable nonlinear wave excitations in
nonlinear fiber and other nonlinear systems.",1410.7536v3
2015-02-13,Baseband Modulation Instability as the Origin of Rogue Waves,"We study the existence and properties of rogue wave solutions in different
nonlinear wave evolution models that are commonly used in optics and
hydrodynamics. In particular, we consider Fokas-Lenells equation, the
defocusing vector nolinear Schr\""odinger equation, and the long-wave-short-wave
resonance equation. We show that rogue wave solutions in all of these models
exist in the subset of parameters where modulation instability is present, if
and only if the unstable sideband spectrum also contains cw or zero-frequency
perturbations as a limiting case (baseband instability). We numerically confirm
that rogue waves may only be excited from a weakly perturbed cw whenever the
baseband instability is present. Conversely, modulation instability leads to
nonlinear periodic oscillations.",1502.03915v1
2015-03-03,Nonlinear acoustic wave generation in a three-phase seabed,"Generation of an acoustic wave by two pump sound waves is studied in a
three-phase marine sediment that consists of a solid frame and the pore water
with air bubbles in it. To avoid shock-wave formation the interaction is
considered in the frequency range where there is a significant amount of sound
velocity dispersion. Nonlinear equations are obtained to describe the
interaction of acoustic waves in the presence of air bubbles. An expression for
the amplitude of the generated wave is obtained and numerical analysis of its
dependence on distance and on the resonance frequency of bubbles is performed.",1503.00901v1
2016-01-05,Vlasov Simulations of Electron-Ion Collision Effects on Damping of Electron Plasma Waves,"Collisional effects can play an essential role in the dynamics of plasma
waves by setting a minimum damping rate and by interfering with wave-particle
resonances. Kinetic simulations of the effects of electron-ion pitch angle
scattering on Electron Plasma Waves (EPWs) are presented here. In particular,
the effects of such collisions on the frequency and damping of small-amplitude
EPWs for a range of collision rates and wave phase velocities are computed and
compared with theory. Both the Vlasov simulations and linear kinetic theory
find the direct contribution of electron-ion collisions to wave damping is
about a factor of two smaller than is obtained from linearized fluid theory. To
our knowledge, this simple result has not been published before.
  Simulations have been carried out using a grid-based (Vlasov) approach, based
on a high-order conservative finite difference method for discretizing the
Fokker-Planck equation describing the evolution of the electron distribution
function. Details of the implementation of the collision operator within this
framework are presented. Such a grid-based approach, which is not subject to
numerical noise, is of particular interest for the accurate measurements of the
wave damping rates.",1601.01002v1
2016-04-23,Surface-wave pulse routing around sharp corners,"The ability to perfectly guide surface electromagnetic waves around
ultra-sharp corners without back-scattering and radiation is in great demand
for various photonic and plasmonic applications. This is fundamentally
difficult to realize because of the dramatic momentum mismatch and wave nature
of radiation at the sharp corners. Here we experimentally demonstrate that a
simple photonic structure, a periodic square array of metallic cylinders
standing on a metal surface, can behaves as a surface-wave photonic crystal
with complete photonic band gap to overcome this bottleneck simply. A
line-defect waveguide can support and guide surface waves around ultra-sharp
corners without perceptible radiation and reflection, achieving almost perfect
transmission efficiency in a broad frequency range. We also demonstrate an
ideal T-shaped splitter to split input surface waves equally into two arms and
a square radiation-suppressed plasmonic open resonator with high quality
factors by simply inducing line-defects in this fully open surface-wave
photonic crystal.",1604.06872v2
2018-07-31,Measurement of interfacial wave dynamics in orbitally shaken cylindrical containers using ultrasound pulse-echo techniques,"We present a novel experiment on interfacial wave dynamics in orbitally
shaken cylindrical vessels containing two- and three fluid layers. The
experiment was designed as a hydrodynamical model for both alu- minum reduction
cells and liquid metal batteries to gain new insights into the rotational wave
motion driven by the metal pad roll instability. Different options are
presented to realize stable and measurable multi-layer stratifications. We
introduce a new acoustic measure- ment procedure allowing to reconstruct wave
ampli- tudes also in opaque liquids by tracking ultrasonic pulse echoes
reflected on the interfaces. Measurements of res- onance curves and phase
shifts were conducted for vary- ing interface positions. A strong influence of
the top and bottom walls were observed, considerably reducing wave amplitudes
and eigenfrequencies, when the inter- face is getting close. Finally, measured
resonance curves were successfully compared with an existing forced wave theory
that we extended to two-layer interfacial waves. The comparison stresses the
importance to carefully control the boundary condition at the contact line.",1807.11768v1
2014-06-14,Energy spectrum of ensemble of weakly nonlinear gravity-capillary waves on a fluid surface,"In this Letter we regard nonlinear gravity-capillary waves with parameter of
nonlinearity being $\varepsilon \sim 0.1 \div 0.25$. For this nonlinearity time
scale separation does not occur and kinetic wave equation does not hold. An
energy cascade in this case is built at the dynamic time scale (D-cascade) and
is computed by the increment chain equation method first introduced in
\emph{Kartashova, \emph{EPL} \textbf{97} (2012), 30004.} We compute for the
first time an analytical expression for the energy spectrum of nonlinear
gravity-capillary waves as an explicit function depending on the ratio of
surface tension to the gravity acceleration. It is shown that its two limits -
pure capillary and pure gravity waves on a fluid surface - coincide with the
previously obtained results. We also discuss relations of the model of
D-cascade with a few known models used in the theory of nonlinear waves such as
Zakharov's equation, resonance of the modes with nonlinear Stokes corrected
frequencies and Benjamin-Feir index. These connections are crucial in the
understanding and forecasting specifics of the energy transport in a variety of
multi-component wave dynamics, from oceanography to optics, from plasma physics
to acoustics.",1406.3779v1
2016-12-06,Alfvén Waves in the Structured Solar Corona,"A simple model of a periodic ensemble of closely packed flux tubes sitting
atop a vertically stratified layer reveals that an incident fast wave from
below preferentially converts almost immediately to Alfv\'en waves in the flux
tubes, with kink waves restricted to at most a very few Fourier modes. This
suggests that observations of coronal kink modes in such structured systems may
greatly underestimate the net wave energy flux being transported into and
through the corona, much of which may reside in harder-to-observe Alfv\'en
waves. The processes of mode conversion/resonant absorption and Alfv\'en phase
mixing are implicated. It is suggested that the Sun's internal p-mode field --
the 5-minute oscillations -- may contribute substantially to the process by
supplying incident fast waves in the chromosphere that scatter and mode-convert
in the tube ensemble.",1612.02064v1
2017-02-24,Instabilities of Internal Gravity Wave Beams,"Internal gravity waves play a primary role in geophysical fluids: they
contribute significantly to mixing in the ocean and they redistribute energy
and momentum in the middle atmosphere. Until recently, most studies were
focused on plane wave solutions. However, these solutions are not a
satisfactory description of most geophysical manifestations of internal gravity
waves, and it is now recognized that internal wave beams with a confined
profile are ubiquitous in the geophysical context.
  We will discuss the reason for the ubiquity of wave beams in stratified
fluids, related to the fact that they are solutions of the nonlinear governing
equations. We will focus more specifically on situations with a constant
buoyancy frequency. Moreover, in light of recent experimental and analytical
studies of internal gravity beams, it is timely to discuss the two main
mechanisms of instability for those beams. i) The Triadic Resonant Instability
generating two secondary wave beams. ii) The streaming instability
corresponding to the spontaneous generation of a mean flow.",1702.07762v2
2021-04-29,Forward Wave Amplification Enhanced Radiation in a 1 THz Harmonic Gyrotron,"Among the most promising terahertz (THz) radiation devices, gyrotrons can
generate powerful THz-wave radiation in an open resonant structure.
Unfortunately, such an oscillation using high-Q axial mode has been
theoretically and experimentally demonstrated to suffer from strong ohmic
losses. In this paper, a solution to such a challenging problem is to include a
narrow belt of lossy section in the interaction circuit to stably constitute
the traveling wave interaction (high-order-axial-mode, HOAM), and employ a
down-tapered magnetic field to amplify the forward-wave component. A scheme
based on the traveling-wave interaction concept is proposed to strengthen
electron beam-wave interaction efficiency and simultaneously reduce the ohmic
loss in a 1-THz third harmonic gyrotron, which is promising for further
advancement of high-power continuous-wave operation.",2104.14108v1
2020-02-10,Plasmon Oscillations and de Broglie's Matter Waves Instabilities,"In this research we study the effect of matter-wave instability on electron
beam transport with arbitrary degree of degeneracy. Particular class of
solutions of the Schr\""{o}dinger-Poisson system is used to model the
electron-beam transport at constant speed. It is shown that such electron-beam
is described by a coupled driven pseudoforce system solution of which leads to
plasmon excitations with dual wave-particle character. The fundamental quantum
mechanical de Broglie relation is found to be due to the resonant interaction
of particle-like plasmon excitation branch with the electron beam drift. We
further obtain a generalized double lengthscale de Broglie wave-particle
relation through which various beam-plasmon instability is studied in this
model. The quantum charge screening and the chemical potential effects on the
matter-wave formation and instabilities are discussed in detail and the
well-known Aharonov-Bohm effect is revisited in current quantum hydrodynamic
model. Current research may further illuminate the origin of matter-wave in
quantum mechanics and lead to clear understanding of novel wave-particle
interactions.",2002.04690v4
2020-06-19,Gravitational waves affect vacuum entanglement,"The entanglement harvesting protocol is an operational way to probe vacuum
entanglement. This protocol relies on two atoms, modelled by Unruh-DeWitt
detectors, that are initially unentangled. These atoms then interact locally
with the field and become entangled. If the atoms remain spacelike separated,
any entanglement between them is a result of entanglement that is `harvested'
from the field. Thus, quantifying this entanglement serves as a proxy for how
entangled the field is across the regions in which the atoms interacted. Using
this protocol, it is demonstrated that while the transition probability of an
individual inertial atom is unaffected by the presence of a gravitational wave,
the entanglement harvested by two atoms depends sensitively on the frequency of
the gravitational wave, exhibiting novel resonance effects when the energy gap
of the detectors is tuned to the frequency of the gravitational wave. This
suggests that the entanglement signature left by a gravitational wave may be
useful in characterizing its properties, and potentially useful in exploring
the gravitational-wave memory effect and gravitational-wave induced
decoherence.",2006.11301v1
2020-12-01,New developments in model-independent Partial-Wave Analysis,"Partial-wave analyses (PWA) are an essential tool for studying resonance
structures in decays with hadronic multi-body final states. For several years,
more model-independent approaches to such analyses have been used for various
decay final states. However, up to now, these methods have mostly been applied
to sub-sets of partial waves, also called freed waves. In this article, we
explore possibilities and limitations of extended model-independent approaches.
We systematically apply various different fit models to the analysis of pseudo
data sets, to study both the impact of the mathematical description used for
the freed waves and the choice of simultaneously freed waves. We can show that
suitable methods exist, which lift restrictions to only sub-sets of freed
partial waves and demonstrate hidden caveats present in previous works.",2012.00474v1
2021-10-30,Wave-particle interactions in quantum plasmas,"Wave-particle interaction (WPI) is one of the most fundamental processes in
plasma physics in which one most prominent example is the Landau damping. Owing
to its excellent energy-exchange mechanism, the WPI has gained increasing
interest not only from theoretical points of view but also its many important
applications including plasma heating and plasma acceleration. In this review
work, we present theoretical backgrounds of linear and nonlinear wave-particle
interactions in quantum plasmas. Specifically, we focus on the wave-particle
interactions for homogeneous plasma waves (i.e., waves with infinite extent
rather than a localized pulse) as well as for propagating electrostatic waves
in the weak and strong quantum regimes to demonstrate the modifications of
several classical features including those associated with resonant and trapped
particles. Finally, the future perspectives of WPI in quantum plasmas are
presented.",2111.00196v2
2021-11-15,Internal wave crystals,"Geophysical fluids such as the ocean and atmosphere can be stratified: their
density depends on the depth. As a consequence, they can host internal gravity
waves that propagate in the bulk of the fluid, far from the surface. These
waves can transport energy and momentum over large distances, thereby affecting
large-scale circulation patterns, as well as the transport of heat, sediments,
nutrients and pollutants in the ocean. When the density stratification is not
uniform, internal waves can exhibit wave phenomena such as resonances,
tunneling, and frequency-dependent transmissions. Spatially periodic density
profiles formed by thermohaline staircases are commonly found in stratified
fluids ranging from the Arctic Ocean to giant planet interiors, and can produce
extended regions with periodically stratified fluid. Here, we report on the
experimental observation of band gaps for internal gravity waves, ranges of
frequencies over which the wave propagation is prohibited in the presence of a
periodic stratification. We show the existence of surface states controlled by
boundary conditions and discuss their topological origin. Our results suggest
that energy transport can be profoundly affected by the presence of periodic
stratifications in geophysical fluids ranging from Earth's oceans to gas
giants.",2111.07984v1
2022-03-04,Electron acceleration from the interaction of three crossed parallel Alfvén waves,"We study the non-linear interaction of three parallel Alfv\'en wave packets
(AWP) in an initially uniform plasma using 2.5D particle-in-a-cell (PIC)
numerical simulations. We aim to help to explain the observation of
suprathermal electrons by multiple Alfv\'en waves collision in regions where
these waves are trapped like IAR (Ionospheric Alfv\'en Resonator), Earth
radiation belts or coronal magnetic loops. In the context of APAWI process that
have been described by Mottez (2012, 2015), the interaction of two parallel
Alfv\'en waves (AW) generates longitudinal density modulations and parallel
electric field at the APAWI crossing region that can accelerate particles
effectively in the direction of the background magnetic field. Our simulations
show that when a third parallel AWP of different initial position arrives at
the APAWI crossing region, it gives rise to a strong parallel electron beams
($V \sim 5--7VTe$) at longitudinal cavity density gradients. We suggest that
velocity drift from outgoing AW generates interface waves in the transverse
direction, which allows propagating waves to develop parallel electric fields
by phase mixing process when the transverse scale of the wavy density gradient
(oblique gradient) is in the range of the electron inertial length.",2203.02575v1
2022-03-24,Gyrokinetic Theory of Low-frequency Electromagnetic Waves in Finite-$β$ Anisotropic Plasmas,"We present a gyrokinetic theory for the electromagnetic waves and
instabilities with frequencies much lower than the ion cyclotron frequency in
finite-$\beta$ anisotropic uniform plasmas. Here, $\beta$ is the ratio between
plasma and magnetic pressures. Kinetic effects due to both the finite Larmor
radii and wave-particle resonances are fully kept in the analysis.
Corresponding linear dispersion relation and wave polarizations, valid for
general $\beta$ value and perpendicular wavelength, are then specifically
derived for a bi-Maxwellian plasma. Analytic expressions for the criteria of
kinetic firehose and mirror instabilities are also given. The mode frequency,
stability, and wave polarization of a broad spectrum of normal modes are then
investigated numerically in a systematic study over a set of parameters. Our
study clearly demonstrates that, due to the finite ion Larmor radius effect,
the ion-sound wave, mirror mode, and shear Alfven wave are intrinsically
coupled.",2203.12953v1
2022-04-04,On the stability of the periodic waves for the Benney system,"We analyze the Benney model for interaction of short and long waves in
resonant water wave interactions. Our particular interest is in the periodic
traveling waves, which we construct and study in detail. The main results are
that, for all natural values of the parameters, the periodic dnoidal waves are
spectrally stable with respect to perturbations of the same period. For another
natural set of parameters, we construct the snoidal waves, which exhibit
instabilities, in the same setup.
  Our results are the first instability results in this context. On the other
hand, the spectral stability established herein improves significantly upon the
work Angulo-Corcho-Hakkaev, which established stability of the dnoidal waves,
on a subset of parameter space, by relying on the Grillakis-Shatah theory. Our
approach, which turns out to give definite answer for the entire domain of
parameters, relies on the instability index theory. Interestingly, end even
though the linearized operators are explicit, our spectral analysis requires
subtle and detailed analysis of matrix Schr\""odinger operators in the periodic
context, which support some interesting features.",2204.01628v1
2022-05-21,Electric Current Induced by Microwave Stark Effect of Electrons on Liquid Helium,"We propose a frequency-mixed effect of Terahertz (THz) and Gigahertz (GHz)
electromagnetic waves in the cryogenic system of electrons floating on liquid
helium surface. The THz wave is near-resonant with the transition frequency
between the lowest two levels of surface state electrons. The GHz wave does not
excite the transitions but generates a GHz-varying Stark effect with the
symmetry-breaking eigenstates of electrons on liquid helium. We show an
effective coupling between the inputting THz and GHz waves, which appears at
the critical point that the detuning between electrons and THz wave is equal to
the frequency of GHz wave. By this coupling, the THz and GHz waves
cooperatively excite electrons and generate the low-frequency ac currents along
the perpendicular direction of liquid helium surface to be experimentally
detected by the image-charge approach [Phys. Rev. Lett. 123, 086801 (2019)].
This offers an alternative approach for THz detections.",2205.10557v1
2022-08-10,Alfvénic waves in the inhomogeneous solar atmosphere,"The solar atmosphere is known to be replete with magneto-hydrodynamic wave
modes, and there has been significant investment in understanding how these
waves propagate through the Sun's atmopshere and deposit their energy into the
plasma. The waves' journey is made interesting by the vertical variation in
plasma quantities that define the solar atmosphere. In addition to this
large-scale inhomogeneity, a wealth of fine-scale structure through the
chromosphere and corona has been brought to light by high-resolution
observations over the last couple of decades. This fine-scale sturcture
represents inhomogeneity that is thought to be perpendicular to the local
magnetic fields. The implications of this form of inhomogeneity on wave
propagation is still being uncovered, but is known to fundamentally change the
nature of MHD wave modes. It also enables interesting physics to arise
including resonances, turbulence and instabilities. Here we review some of the
key insights into how the inhomogeneity influences Alfv\'enic wave propagation
through the Sun's atmosphere, discussing both inhomogeneities parallel and
perpendicular to the magnetic field.",2208.05222v2
2023-07-01,Interaction of interfacial waves with an external force: The Benjamin-Ono equation framework,"This study aims to explore the complex interactions between an internal
solitary wave and an external force using the Benjamin-Ono equation as the
theoretical framework. The investigation encompasses both asymptotic and
numerical approaches. By assuming a small amplitude for the external force, we
derive a dynamical system that describes the behavior of the solitary wave
amplitude and the position of its crest. Our findings reveal three distinct
scenarios: (i) resonance between the solitary wave and the external force, (ii)
oscillatory motion with closed orbits, and (iii) displacement from the initial
position while maintaining the wave direction. However, through numerical
simulations, we observe a different relationship between the amplitude of the
solitary wave and its crest position. Specifically, for external forces of
small amplitude, the simulations indicate the presence of an unstable spiral
pattern. Conversely, when subjected to external forces of larger amplitudes,
the solitary wave exhibits a stable spiral trajectory which resembles the
classical damped mass-spring system.",2307.00326v1
2023-09-12,Energy spectra of non-local internal gravity wave turbulence,"Starting from the classical formulation of the weak turbulence theory in a
density stratified fluid, we derive a simplified version of the kinetic
equation of internal gravity wave turbulence. This equation allows us to
uncover scaling laws for the spatial and temporal energy spectra of internal
wave turbulence which are consistent with typical scaling exponents observed in
the oceans. The keystone of our description is the assumption that the energy
transfers are dominated by a class of non-local resonant interactions, known as
the ``induced diffusion'' triads, which conserve the ratio between the wave
frequency and vertical wave number. Our analysis remarkably shows that the
internal wave turbulence cascade is associated to an apparent constant flux of
wave action.",2309.06181v2
2024-04-12,Observation of Alfvén Wave Reflection in the Solar Chromosphere: Ponderomotive Force and First Ionization Potential Effect,"We investigate the propagation of Alfv\'en waves in the solar chromosphere,
distinguishing between upward and downward propagating waves. We find clear
evidence for the reflection of waves in the chromosphere and differences in
propagation between cases with waves interpreted to be resonant or nonresonant
with the overlying coronal structures. This establishes the wave connection to
coronal element abundance anomalies through the action of the wave
ponderomotive force on the chromospheric plasma, which interacts with
chromospheric ions but not neutrals, thereby providing a novel mechanism of
ion-neutral separation. This is seen as a ""First Ionization Potential Effect""
when this plasma is lifted into the corona, with implications elsewhere on the
Sun for the origin of the slow speed solar wind and its elemental composition.",2404.08305v1
2003-07-28,Exciton spin relaxation in resonantly excited CdTe/ZnTe self-assembled quantum dots,"We study the exciton spin relaxation in CdTe self-assembled quantum dots by
using polarized photoluminescence spectroscopy in magnetic field. The
experiments on single CdTe quantum dots and on large quantum dot ensembles show
that by combining phonon-assisted absorption with circularly polarized resonant
excitation the spin-polarized excitons are photo-excited directly into the
ground states of quantum dots. We find that for single symmetric quantum dots
at B=0 T, where the exciton levels are degenerate, the spins randomize very
rapidly, so that no net spin polarization is observed. In contrast, when this
degeneracy is lifted by applying external magnetic field, optically created
spin-polarized excitons maintain their polarization on a time scale much longer
than the exciton recombination time. We also observe that the exciton spin
polarization is conserved when the splitting between exciton states is caused
by quantum dot shape asymmetry. Similar behavior is found in a large ensemble
of CdTe quantum dots. These results show that while exciton spins scatter
rapidly between degenerate states, the spin relaxation time increases by orders
of magnitude as the exciton spin states in a quantum dot become non-degenerate.
Finally, due to strong electronic confinement in CdTe quantum dots, the large
spin polarization of excitons shows no dependence on the number of phonons
emitted between the virtual state and the exciton ground state during the
excitation.",0307674v1
2009-06-08,SU(2) slave-boson formulation of spin nematic states in S=1/2 frustrated ferromagnets,"An SU(2) slave boson formulation of bond-type spin nematic orders is
developed in frustrated ferromagnets, where the spin nematic states are
described as the resonating spin-triplet valence bond (RVB) states. The
d-vectors of spin-triplet pairing ansatzes play the role of the directors in
the bond-type spin quadrupolar states. The low-energy excitations around such
spin-triplet RVB ansatzes generally comprise the (potentially massless) gauge
bosons, massless Goldstone bosons, and spinon individual excitations. Extending
the projective symmetry group argument to the spin-triplet ansatzes, we show
how to identify the number of massless gauge bosons efficiently. Applying this
formulation, we next (i) enumerate possible mean field solutions for the S=1/2
ferromagnetic J1-J2 Heisenberg model on the square lattice, with ferromagnetic
nearest neighbor J1 and competing antiferromagnetic next-nearest neighbor J2,
and (ii) argue their stability against small gauge fluctuations. As a result,
two stable spin-triplet RVB ansatzes are found in the intermediate coupling
regime around J1:J2 \simeq 1:0.4. One is the Z_2 Balian-Werthamer (BW) state
stabilized by the Higgs mechanism and the other is the SU(2) chiral p-wave
(Anderson-Brinkman-Morel) state stabilized by the Chern-Simon mechanism. The
former Z_2 BW state in fact shows the same bond-type spin quadrupolar order as
found in the previous exact diagonalization study [N. Shannon et al., Phys.
Rev. Lett. 96, 027213 (2006)].",0906.1248v3
2010-09-01,Probing spin relaxation in an individual InGaAs quantum dot using a single electron optical spin memory device,"We demonstrate all optical electron spin initialization, storage and readout
in a single self-assembled InGaAs quantum dot. Using a single dot charge
storage device we monitor the relaxation of a single electron over long
timescales exceeding 40{\mu}s. The selective generation of a single electron in
the quantum dot is performed by resonant optical excitation and subsequent
partial exciton ionization; the hole is removed from the quantum dot whilst the
electron remains stored. When subject to a magnetic field applied in Faraday
geometry, we show how the spin of the electron can be prepared with a
polarization up to 65% simply by controlling the voltage applied to the gate
electrode. After generation, the electron spin is stored in the quantum dot
before being read out using an all optical implementation of spin to charge
conversion technique, whereby the spin projection of the electron is mapped
onto the more robust charge state of the quantum dot. After spin to charge
conversion, the charge state of the dot is repeatedly tested by pumping a
luminescence recycling transition to obtain strong readout signals. In
combination with spin manipulation using fast optical pulses or microwave
pulses, this provides an ideal basis for probing spin coherence in single
self-assembled quantum dots over long timescales and developing optimal methods
for coherent spin control.",1009.0207v1
2015-02-10,Disentangling relativistic spin torques in a ferromagnet/semiconductor bilayer,"Recently discovered relativistic spin torques induced by a lateral current at
a ferromagnet/paramagnet interface are a candidate spintronic technology for a
new generation of electrically-controlled magnetic memory devices.
Phenomenologically, the torques have field-like and antidamping-like components
with distinct symmetries. Microscopically, they are considered to have two
possible origins. In one picture, a spin-current generated in the paramagnet
via the relativistic spin Hall effect (SHE) is absorbed in the ferromagnet and
induces the spin transfer torque (STT). In the other picture, a non-equilibrium
spin-density is generated via the relativistic inverse spin galvanic effect
(ISGE) and induces the spin-orbit torque (SOT) in the ferromagnet. From the
early observations in paramagnetic semiconductors, SHE and ISGE are known as
companion phenomena that can both allow for electrically aligning spins in the
same structure. It is essential for our basic physical understanding of the
spin torques at the ferromagnet/paramagnet interface to experimentally
disentangle the SHE and ISGE contributions. To achieve this we prepared an
epitaxial transition-metal-ferromagnet/semiconductor-paramagnet single-crystal
structure and performed a room-temperature vector analysis of the relativistic
spin torques by means of the all-electrical ferromagnetic resonance (FMR)
technique. By design, the field-like torque is governed by the ISGE-based
mechanism in our structure while the antidamping-like torque is due to the
SHE-based mechanism",1502.02870v1
2015-08-21,Nuclear spin decoherence of neutral $^{31}$P donors in silicon: Effect of environmental $^{29}$Si nuclei,"Spectral diffusion arising from $^{29}$Si nuclear spin flip-flops, known to
be a primary source of electron spin decoherence in silicon, is also predicted
to limit the coherence times of neutral donor nuclear spins in silicon. Here,
the impact of this mechanism on $^{31}$P nuclear spin coherence is measured as
a function of $^{29}$Si concentration using X-band pulsed electron nuclear
double resonance (ENDOR). The $^{31}$P nuclear spin echo decays show that
decoherence is controlled by $^{29}$Si flip-flops resulting in both fast
(exponential) and slow (non-exponential) spectral diffusion processes. The
decay times span a range from 100 ms in crystals containing 50% $^{29}$Si to 3
s in crystals containing 1% $^{29}$Si. These nuclear spin echo decay times for
neutral donors are orders of magnitude longer than those reported for ionized
donors in natural silicon. The electron spin of the neutral donors `protects'
the donor nuclear spins by suppressing $^{29}$Si flip-flops within a `frozen
core', as a result of the detuning of the $^{29}$Si spins caused by their
hyperfine coupling to the electron spin.",1508.05362v1
2015-08-31,Spin Response to Localized Pumps: Exciton Polaritons Versus Electrons and Holes,"Polariton polarization can be described in terms of a pseudospin which can be
oriented along the $x,\,y,$ or $z$ axis, similarly to electron and hole spin.
Unlike electrons and holes where time-reversal symmetry requires that the
spin-orbit interaction be odd in the momentum, the analogue of the spin-orbit
interaction for polaritons, the so-called TE-TM splitting, is even in the
momentum. We calculate and compare spin transport of polariton, electron, and
hole systems, in the diffusive regime of many scatterings. After dimensional
rescaling diffusive systems with spatially uniform particle densities have
identical dynamics, regardless of the particle type. Differences between the
three particles appear in spatially non-uniform systems, with pumps at a
specific localized point. We consider both oscillating pumps and transient
(delta-function) pumps. In such systems each particle type produces distinctive
spin patterns. The particles can be distinguished by their differing spatial
multipole character, their response and resonances in a perpendicular magnetic
field, and their relative magnitude which is largest for electrons and weakest
for holes. These patterns are manifested both in response to unpolarized pumps
which produce in-plane and perpendicular spin signals, and to polarized pumps
where the spin precesses from in-plane to out-of-plane and vice versa. These
results will be useful for designing systems with large spin polarization
signals, for identifying the dominant spin-orbit interaction and measuring
subdominant terms in experimental devices, and for measuring the scattering
time and the spin-orbit coupling's magnitude.",1508.07863v2
2016-06-10,Large Stark tuning of donor electron spin quantum bits in germanium,"Donor electron spins in semiconductors make exceptional quantum bits because
of their long coherence times and compatibility with industrial fabrication
techniques. Despite many advances in donor-based qubit technology, it remains
difficult to selectively manipulate single donor electron spins. Here, we show
that by replacing the prevailing semiconductor host material (silicon) with
germanium, donor electron spin qubits can be electrically tuned by more than an
ensemble linewidth, making them compatible with gate addressable quantum
computing architectures. Using X-band pulsed electron spin resonance, we
measured the Stark effect for donor electron spins in germanium. We resolved
both spin-orbit and hyperfine Stark shifts and found that at 0.4 T, the
spin-orbit Stark shift dominates. The spin-orbit Stark shift is highly
anisotropic, depending on the electric field orientation relative to the
crystal axes and external magnetic field. When the Stark shift is maximized,
the spin-orbit Stark parameter is four orders of magnitude larger than in
silicon. At select orientations a hyperfine Stark effect was also resolved and
is an order of magnitude larger than in silicon. We report the Stark parameters
for $^{75}$As and $^{31}$P donor electrons and compare them to the available
theory. Our data reveal that $^{31}$P donors in germanium can be tuned by at
least four times the ensemble linewidth making germanium an appealing new host
material for spin qubits that offers major advantages over silicon.",1606.03314v2
2017-12-14,Determination of the spin Hall angle in single-crystalline Pt films from spin pumping experiments,"We report on the determination of the spin Hall angle and the identification
of the role of the interface roughness for the inverse spin Hall effect (ISHE)
in ultra-clean, defect-reduced epitaxial Pt films. By applying vector network
analyzer ferromagnetic resonance spectroscopy to a series of single crystalline
Fe (12 nm) /Pt (t$_\text{Pt}$) bilayers we determine the real part of the spin
mixing conductance $(4.4\:\pm\:0.2)\cdot 10^{19}\: $m$^{-2}$ and reveal a very
small spin diffusion length in the epitaxial Pt $(1.1\:\pm\:0.1)$ nm film. We
investigate the spin pumping and ISHE in a stripe microstucture excited by a
microwave coplanar waveguide (CPW) antenna. By using their different angular
dependencies, we distinguish between spin rectification effects and the inverse
spin Hall effect. The relatively large value of the spin Hall angle $(5.7 \pm
1.4)\: \% $ hints that interface engineering by epitaxially grown non-magnetic
materials can increase the spin-to-charge current conversion efficiency.",1712.05334v2
2018-08-02,Generation of pure superconducting spin current in magnetic heterostructures via non-locally induced magnetism due to Landau Fermi-liquid effects,"We propose a mechanism for the generation of pure superconducting
spin-current carried by equal-spin triplet Cooper pairs in a superconductor (S)
sandwiched between a ferromagnet (F) and a normal metal (N$_{\rm so}$) with
intrinsic spin-orbit coupling. We show that in the presence of Landau
Fermi-liquid interactions the superconducting proximity effect can induce
non-locally a ferromagnetic exchange field in the normal layer, which
disappears above the superconducting transition temperature of the structure.
The internal Landau Fermi-liquid exchange field leads to the onset of a spin
supercurrent associated with the generation of long-range spin-triplet
superconducting correlations in the trilayer. We demonstrate that the magnitude
of the spin supercurrent as well as the induced magnetic order in the N$_{\rm
so}$ layer depends critically on the superconducting proximity effect between
the S layer and the F and N$_{\rm so}$ layers and the magnitude of the relevant
Landau Fermi-liquid interaction parameter. We investigate the effect of spin
flip processes on this mechanism. Our results demonstrate the crucial role of
Landau Fermi-liquid interaction in combination with spin-orbit coupling for the
creation of spin supercurrent in superconducting spintronics, and give a
possible explanation of a recent experiment utilizing spin-pumping via
ferromagnetic resonance [Jeon $\it{ et}$ $\it{al.}$, Nat. Mat. ${\bf 17}$, 499
(2018)].",1808.01045v1
2017-02-20,Valley dependent anisotropic spin splitting in silicon quantum dots,"Spin qubits hosted in silicon (Si) quantum dots (QD) are attractive due to
their exceptionally long coherence times and compatibility with the silicon
transistor platform. To achieve electrical control of spins for qubit
scalability, recent experiments have utilized gradient magnetic fields from
integrated micro-magnets to produce an extrinsic coupling between spin and
charge, thereby electrically driving electron spin resonance (ESR). However,
spins in silicon QDs experience a complex interplay between spin, charge, and
valley degrees of freedom, influenced by the atomic scale details of the
confining interface. Here, we report experimental observation of a valley
dependent anisotropic spin splitting in a Si QD with an integrated micro-magnet
and an external magnetic field. We show by atomistic calculations that the
spin-orbit interaction (SOI), which is often ignored in bulk silicon, plays a
major role in the measured anisotropy. Moreover, inhomogeneities such as
interface steps strongly affect the spin splittings and their valley
dependence. This atomic-scale understanding of the intrinsic and extrinsic
factors controlling the valley dependent spin properties is a key requirement
for successful manipulation of quantum information in Si QDs.",1702.06210v2
2021-07-13,Investigation of spin-phonon coupling and local magnetic properties in magnetoelectric Fe2TeO6,"Spin-phonon coupling originated from spin-lattice correlation depends upon
different exchange interactions in transition metal oxides containing 3d
magnetic ions. Spin-lattice coupling can influence the coupling mechanism in
magnetoelectric material. To understand the spin-lattice correlation in inverse
trirutile Fe2TeO6 (FTO), magnetic properties and phonon spectra are studied.
Signature of short-range magnetic correlation induced by 5/2-5/2 dimeric
interaction and magnetic anomaly at 150 K is perceived apart from the familiar
sharp transition (TN~210K) corresponding to long-range order by magnetization
and heat capacity measurement. The magnetic transitions and the spin dynamics
are further locally probed by muon spin resonance ({\mu}SR) measurement in both
zero fields (ZF) and longitudinal field (LF) mode. Three dynamically distinct
temperature regimes; (i) T >TN, (ii) TN>T>150 K, and (iii) T<150 K, are
observed. A swift change in spin dynamics is realized at 150K by {\mu}SR,
though previous studies suggest long-range antiferromagnetic order. The
observation of renormalization of different Raman modes below 210K suggests the
existence of spin-phonon coupling in the material. The coupling strength is
quantified as in the range 0.1-1.2 cm-1 following the two-spin cluster
approximation. We propose that the spin-phonon coupling is mediated by the
Fe-O2-Fe interbilayer exchange play a significant role in ME coupling observed
in the material.",2107.06269v2
2022-11-22,Generation of out-of-plane polarized spin current by spin swapping,"The generation of spin currents and their application to the manipulation of
magnetic states is fundamental to spintronics. Of particular interest are
chiral antiferromagnets that exhibit properties typical of ferromagnetic
materials even though they have negligible magnetization. Here, we report the
generation of a robust spin current with both in-plane and out-of-plane spin
polarization in epitaxial thin films of the chiral antiferromagnet Mn3Sn in
proximity to permalloy thin layers. By employing temperature-dependent
spin-torque ferromagnetic resonance, we find that the chiral antiferromagnetic
structure of Mn3Sn is responsible for an in-plane polarized spin current that
is generated from the interior of the Mn3Sn layer and whose temperature
dependence follows that of this layer's antiferromagnetic order. On the other
hand, the out-of-plane spin polarized spin current is unrelated to the chiral
antiferromagnetic structure and is instead the result of scattering from the
Mn3Sn/permalloy interface. We substantiate the later conclusion by performing
studies with several other non-magnetic metals all of which are found to
exhibit out-of-plane polarized spin currents arising from the spin swapping
effect.",2211.12398v1
2023-01-19,RIXS observation of bond-directional nearest-neighbor excitations in the Kitaev material Na$_2$IrO$_3$,"Spin-orbit coupling locks spin direction and spatial orientation and
generates, in semi-classical magnets, a local spin easy-axis and associated
ordering. Quantum spin-1/2's defy this fate: rather than spins becoming locally
anisotropic, the spin-spin interactions do. Consequently interactions become
dependent on the spatial orientation of bonds between spins, prime theoretical
examples of which are Kitaev magnets. Bond-directional interactions imply the
existence of bond-directional magnetic modes, predicted spin excitations that
render crystallographically equivalent bonds magnetically inequivalent, which
yet have remained elusive experimentally. Here we show that resonant inelastic
x-ray scattering allows us to explicitly probe the bond-directional character
of magnetic excitations. To do so, we use a scattering plane spanned by one
bond and the corresponding spin component and scan a range of momentum transfer
that encompasses multiple Brillouin zones. Applying this approach to
Na$_2$IrO$_3$ we establish the different bond-directional characters of
magnetic excitations at 10 meV and 45 meV. Combined with the observation of
spin-spin correlations that are confined to a single bond, this experimentally
validates the Kitaev character of exchange interactions long proposed for this
material.",2301.08340v1
2023-07-17,Nematic spin correlations pervading the phase diagram of FeSe$_{1-x}$S$_{x}$,"We use resonant inelastic X-ray scattering (RIXS) at the Fe-L$_3$ edge to
study the spin excitations of uniaxial-strained and unstrained
FeSe$_{1-x}$S$_{x}$ ($0\leq x\leq0.21$) samples. The measurements on unstrained
samples reveal dispersive spin excitations in all doping levels, which show
only minor doping dependence in energy dispersion, lifetime, and intensity,
indicating that high-energy spin excitations are only marginally affected by
sulfur doping. RIXS measurements on uniaxial-strained samples reveal that the
high-energy spin-excitation anisotropy observed previously in FeSe is also
present in the doping range $0< x\leq0.21$ of FeSe$_{1-x}$S$_{x}$. The
spin-excitation anisotropy persists to a high temperature up to $T>200$ K in
$x=0.18$ and reaches a maximum around the nematic quantum critical doping
($x_c\approx0.17$). Since the spin-excitation anisotropy directly reflects the
existence of nematic spin correlations, our results indicate that high-energy
nematic spin correlations pervade the regime of nematicity in the phase diagram
and are enhanced by the nematic quantum criticality. These results emphasize
the essential role of spin fluctuations in driving electronic nematicity and
open the door for uniaxial strain tuning of spin excitations in quantum
materials hosting strong magnetoelastic coupling and electronic nematicity.",2307.08181v1
2023-07-28,Superconducting-Spin Reorientation in Spin-Triplet Multiple Superconducting Phases of UTe2,"Superconducting (SC) state has spin and orbital degrees of freedom, and
spin-triplet superconductivity shows multiple SC phases due to the presence of
these degrees of freedom. However, the observation of spin-direction rotation
occurring inside the SC state (SC spin rotation) has hardly been reported.
UTe2, a recently discovered topological superconductor, exhibits various SC
phases under pressure: SC state at ambient pressure (SC1), high-temperature SC
state above 0.5 GPa (SC2), and low-temperature SC state above 0.5 GPa (SC3). We
performed nuclear magnetic resonance and AC susceptibility measurements on
single-crystal UTe2. The b-axis spin susceptibility remains unchanged in SC2,
unlike in SC1, and decreases below the SC2-SC3 transition with spin modulation.
These unique properties in SC3 arise from the coexistence of two SC order
parameters. Our NMR results confirm the spin-triplet superconductivity with SC
spin parallel to b in SC2, and unveil the remaining of spin degrees of freedom
in superconducting UTe2.",2307.15784v1
2022-01-31,Precisely computing bound orbits of spinning bodies around black holes I: General framework and results for nearly equatorial orbits,"Very large mass ratio binary black hole systems are of interest both as a
clean limit of the two-body problem in general relativity, as well as for their
importance as sources of low-frequency gravitational waves. At lowest order,
the smaller body moves along a geodesic of the larger black hole's spacetime.
Post-geodesic effects include the gravitational self force, which incorporates
the backreaction of gravitational-wave emission, and the spin-curvature force,
which arises from coupling of the small body's spin to the black hole's
spacetime curvature. In this paper, we describe a method for precisely
computing bound orbits of spinning bodies about black holes. Our analysis
builds off of pioneering work by Witzany which demonstrated how to describe the
motion of a spinning body to linear order in the small body's spin. Exploiting
the fact that in the large mass-ratio limit spinning-body orbits are close to
geodesics and using closed-form results due to van de Meent describing
precession of the small body's spin along black hole orbits, we develop a
frequency-domain formulation of the motion which can be solved very precisely.
We examine a range of orbits with this formulation, focusing in this paper on
orbits which are eccentric and nearly equatorial (i.e., the orbit's motion is
$\mathcal{O}(S)$ out of the equatorial plane), but for which the small body's
spin is arbitrarily oriented. We discuss generic orbits with general small-body
spin orientation in a companion paper. We characterize the behavior of these
orbits and show how the small body's spin shifts the frequencies $\Omega_r$ and
$\Omega_\phi$ which affect orbital motion. These frequency shifts change
accumulated phases which are direct gravitational-wave observables,
illustrating the importance of precisely characterizing these quantities for
gravitational-wave observations. (Abridged)",2201.13334v2
2018-02-16,Light isovector resonances in $π^- p \to π^-π^-π^+ p$ at 190 GeV/${\it c}$,"We have performed the most comprehensive resonance-model fit of
$\pi^-\pi^-\pi^+$ states using the results of our previously published
partial-wave analysis (PWA) of a large data set of diffractive-dissociation
events from the reaction $\pi^- + p \to \pi^-\pi^-\pi^+ + p_\text{recoil}$ with
a 190 GeV/$c$ pion beam. The PWA results, which were obtained in 100 bins of
three-pion mass, $0.5 < m_{3\pi} < 2.5$ GeV/$c^2$, and simultaneously in 11
bins of the reduced four-momentum transfer squared, $0.1 < t' < 1.0$
$($GeV$/c)^2$, are subjected to a resonance-model fit using Breit-Wigner
amplitudes to simultaneously describe a subset of 14 selected waves using 11
isovector light-meson states with $J^{PC} = 0^{-+}$, $1^{++}$, $2^{++}$,
$2^{-+}$, $4^{++}$, and spin-exotic $1^{-+}$ quantum numbers. The model
contains the well-known resonances $\pi(1800)$, $a_1(1260)$, $a_2(1320)$,
$\pi_2(1670)$, $\pi_2(1880)$, and $a_4(2040)$. In addition, it includes the
disputed $\pi_1(1600)$, the excited states $a_1(1640)$, $a_2(1700)$, and
$\pi_2(2005)$, as well as the resonancelike $a_1(1420)$. We measure the
resonance parameters mass and width of these objects by combining the
information from the PWA results obtained in the 11 $t'$ bins. We extract the
relative branching fractions of the $\rho(770) \pi$ and $f_2(1270) \pi$ decays
of $a_2(1320)$ and $a_4(2040)$, where the former one is measured for the first
time. In a novel approach, we extract the $t'$ dependence of the intensity of
the resonances and of their phases. The $t'$ dependence of the intensities of
most resonances differs distinctly from the $t'$ dependence of the nonresonant
components. For the first time, we determine the $t'$ dependence of the phases
of the production amplitudes and confirm that the production mechanism of the
Pomeron exchange is common to all resonances.",1802.05913v2
2003-06-08,"Spin-exchange interactions of spin-one bosons in optical lattices: singlet, nematic and dimerized Phases","We consider insulating phases of cold spin-1 bosonic particles with
antiferromagnetic interactions, such as Na-23, in optical lattices. We show
that spin-exchange interactions give rise to several distinct phases, which
differ in their spin correlations. In two- and three- dimensional lattices
insulating phases with odd number of particles per site are always nematic. For
insulating states with even number of particles per site there is always a
spin-singlet phase and there may also be a first-order transition into the
nematic phase. The nematic phase breaks spin rotational symmetry, but preserves
time reversal symmetry, and has gapless spin-wave excitations. The spin singlet
phase does not break spin symmetry and has a gap to all excitations. In
one-dimensional lattices insulating phases with odd number of particles per
site always have a regime where translational symmetry is broken and the ground
state is dimerized. We discuss signatures of various phases in Bragg scattering
and time-of-flight measurements.",0306204v2
2003-11-26,Topological spin pumps I,"We have established a semiclassical kinetic approach for various spin
correlated pumping phenomena incorporating spin rotation in wave functions into
transport equations. We employ this technique to study topological pumps and
illustrate spin pumping in a few models where various spin configurations or
topological motors drive adiabatic pumps. In the Rashba model we find that a
topological spin pump is driven by a meron with positive one half skyrmion
charge, the size of which can be controlled by external gates or Zeeman fields.
In the Dresselhaus model on the other hand, electron spins are pumped out by a
negative meron. We examine effects of Zeeman fields on topological spin pumping
and responses of fermi seas in various pumps. The phenomena of topological
pumping are attributed to topological Stern-Gerlach splitting and occur in a
transverse direction along which charge pumping currents either vanish or are
negligible. The transport equations established here might also be applied for
the studies of anomalous Hall effect and spin Hall effect as demonstrated in
one of appendices.",0311612v3
2005-02-08,Monte Carlo Simulations of Spin-Diffusion in a 2-D Heisenberg Paramagnet,"We study spin diffusion and spin waves in paramagnetic quantum crystals
(solid He-3, for example) by direct simulation of a square lattice of atoms
interacting via a nearest-neighbor Heisenberg exchange Hamiltonian. Recently,
Cowan and Mullin have used a moments method to study spin transport at
arbitrary polarizations. We test their analytic results by calculating the
statistical spin correlation function from molecular dynamics simulations using
a Monte Carlo algorithm to average over initial spin configurations. Since it
is not practical to diagonalize the S=1/2 exchange Hamiltonian for a lattice
which is of sufficient size to study long-wavelength (hydrodynamic)
fluctuations, we instead study the S -> infinity limit and treat each spin as a
vector with a classical equation of motion. We compare our simulations with the
assumptions of the moments method regarding the short-time behavior and the
long exponential tail of the correlation function. We also present our
numerical results for the polarization dependence of the longitudinal spin
diffusion coefficient and the complex transverse spin diffusion coefficient.",0502214v1
2005-06-27,Spin transverse force on spin current in an electric field,"As a relativistic quantum mechanical effect, it is shown that the electric
field exerting a transverse force on an electron spin 1/2 only if the electron
is moving and the spin is polarized along the electric field. The spin force,
analogue to the Lorentz for on an electron charge in a magnetic field, is
perpendicular to the electric field and the spin current polarized anong the
electric field. This spin-dependent force can be used to understand the
zitterbewegung of electron wave packet with spin-orbit coupling and is relevant
to the generation of the charge Hall effect driven by the spin current in
semiconductors.",0506676v2
2006-03-14,Spin-orbit lateral superlattices: energy bands and spin polarization in 2DEG,"The Bloch spinors, energy spectrum and spin density in energy bands are
studied for the two-dimensional electron gas (2DEG) with Rashba spin-orbit (SO)
interaction subject to one-dimensional (1D) periodic electrostatic potential of
a lateral superlattice. The space symmetry of the Bloch spinors with spin
parity is studied. It is shown that the Bloch spinors at fixed quasimomentum
describe the standing spin waves with the wavelength equal to the superlattice
period. The spin projections in these states have the components both parallel
and transverse to the 2DEG plane. The anticrossing of the energy dispersion
curves due to the interplay between the SO and periodic terms is observed,
leading to the spin flip. The relation between the spin parity and the
interband optical selection rules is discussed, and the effect of magnetization
of the SO superlattice in the presence of external electric field is predicted.",0603364v1
2006-05-29,Disturbance of spin equilibrium by current through the interface of noncollinear ferromagnets,"Boundary conditions are derived that determine the penetration of spin
current through an interface of two non-collinear ferromagnets with an
arbitrary angle between their magnetization vectors. We start from the
well-known transformation properties of an electron spin wave functions under
the rotation of a quantization axis. It allows directly find the connection
between partial electric current densities for different spin subbands of the
ferromagnets. No spin scattering is assumed in the near interface region, so
that spin conservation takes place when electron intersects the boundary. The
continuity conditions are found for partial chemical potential differences in
the situation. Spatial distribution of nonequilibrium electron magnetizations
is calculated under the spin current flowing through a contact of two
semi-infinite ferromagnets. The distribution describes the spin accumulation
effect by current and corresponding shift of the potential drop at the
interface. These effects appear strongly dependent on the relation between spin
contact resistances at the interface.",0605694v2
2006-12-08,Spin transport in Heisenberg antiferromagnets,"We analyze spin transport in insulating antiferromagnets described by the XXZ
Heisenberg model in two and three dimensions. Spin currents can be generated by
a magnetic-field gradient or, in systems with spin-orbit coupling,
perpendicular to a time-dependent electric field. The Kubo formula for the
longitudinal spin conductivity is derived analogously to the Kubo formula for
the optical conductivity of electronic systems. The spin conductivity is
calculated within interacting spin-wave theory. In the Ising regime, the XXZ
magnet is a spin insulator. For the isotropic Heisenberg model, the
dimensionality of the system plays a crucial role: In d=3 the regular part of
the spin conductivity vanishes linearly in the zero frequency limit, whereas in
d=2 it approaches a finite zero frequency value.",0612215v1
2003-04-21,Spin symmetry in the anti-nucleon spectrum,"We discuss spin and pseudo-spin symmetry in the spectrum of single nucleons
and single anti-nucleons in a nucleus. As an example we use relativistic mean
field theory to investigate single anti-nucleon spectra. We find a very well
developed spin symmetry in single anti-neutron and single anti-proton spectra.
The dominant components of the wave functions of the spin doublet are almost
identical. This spin symmetry in anti-particle spectra and the pseudo-spin
symmetry in particle spectra have the same origin. However it turns out that
the spin symmetry in anti-nucleon spectra is much better developed than the
pseudo-spin symmetry in normal nuclear single particle spectra.",0304067v2
2008-07-08,"Spin rotation, spin filtering, and spin transfer in directional tunneling through non-centrosymmetric semiconductor barriers","We consider spin-dependent tunneling through a gallium arsenide barrier, a
material which has no inversion symmetry. We are dealing with free electrons,
with one effective mass and a spin-splitting in the barrier material. When we
take into account both the spin-orbit interaction and the absence of the
inversion symmetry, the evanescent states in the barrier are spin split and the
tunneling process can become rather involved. Along some crystallographic
directions, the incident wave experiences spin filtering during the tunneling.
These results open stimulating perspectives for spin manipulation in tunnel
devices.",0807.1243v3
2010-03-01,The qubit states decoherence in antiferromagnet-based nuclear spin model of quantum register,"This study deals with the further development of nuclear spin model of
scalable quantum register, which presents the one-dimensional chain of the
magnetic atoms with nuclear spins 1/2, substituting the basic atoms in the
plate of nuclear spin-free easy-axis 3D antiferromagnet. The decoherence rates
of one qubit state and entanglement state of two removed qubits and
longitudinal relaxation rates are caused by the interaction of nuclear
spins-qubits with virtual spin waves in antiferromagnet ground state were
calculated. It was considered also one qubit adiabatic decoherence, is caused
by the interaction of nuclear spin of quantum register with nuclear spins of
randomly distributed isotopes, substituting the basic nuclear spin-free
isotopes of antiferromagnet. We have considered finally encoded DFS
(Decoherence-Free Subspaces) logical qubits are constructed on clusters of the
four-physical qubits, given by the two states with zero total angular momentum.",1003.0170v2
2010-04-03,Spin-selective Peierls transition in interacting one-dimensional conductors with spin-orbit interaction,"Interacting one-dimensional conductors with Rashba spin-orbit coupling are
shown to exhibit a spin-selective Peierls-type transition into a mixed
spin-charge-density-wave state. The transition leads to a gap for one-half of
the conducting modes, which is strongly enhanced by electron-electron
interactions. The other half of the modes remains in a strongly renormalized
gapless state and conducts opposite spins in opposite directions, thus
providing a perfect spin filter. The transition is driven by magnetic field and
by spin-orbit interactions. As an example we show for semiconducting quantum
wires and carbon nanotubes that the gap induced by weak magnetic fields or
intrinsic spin-orbit interactions can get renormalized by 1 order of magnitude
up to 10 - 30 K.",1004.0467v2
2010-04-08,Coupling of bonding and antibonding electron orbitals in double quantum dots by spin-orbit interaction,"We perform a systematic exact diagonalization study of spin-orbit coupling
effects for stationary few-electron states confined in quasi two-dimensional
double quantum dots. We describe the spin-orbit-interaction induced coupling
between bonding and antibonding orbitals and its consequences for
magneto-optical absorption spectrum. The spin-orbit coupling for odd electron
numbers (one, three) %only weakly perturbs the ground-state wave functions.
%Nevertheless, %the spin-orbit interaction opens avoided crossings between low
energy excited levels of opposite spin orientation and opposite spatial parity.
For two-electrons the spin-orbit coupling allows for low-energy optical
transitions that are otherwise forbidden by spin and parity selection rules. We
demonstrate that the energies of optical transitions can be significantly
increased by an in-plane electric field but only for odd electron numbers.
Occupation of single-electron orbitals and effects of spin-orbit coupling on
electron distribution between the dots are also discussed.",1004.1250v1
2011-10-06,Spin and pseudospin symmetry along with orbital dependency of the Dirac-Hulthen problem,"The role of the Hulthen potential on the spin and pseudospin symmetry
solutions is investigated systematically by solving the Dirac equation with
attractive scalar S(r) and repulsive vector V(r) potentials. The spin and
pseudospin symmetry along with orbital dependency (pseudospin-orbit and
spin-orbit dependent couplings) of the Dirac equation are included to the
solution by introducing the Hulthen-square approximation. This effective
approach is based on forming the spin and pseudo-centrifugal kinetic energy
term from the square of the Hulthen potential. The analytical solutions of the
Dirac equation for the Hulthen potential with the spin-orbit and
pseudospin-orbit-dependent couplings are obtained by using the Nikiforov-Uvarov
(NU) method. The energy eigenvalue equations and wave functions for various
degenerate states are presented for several spin-orbital, pseudospin-orbital
and radial quantum numbers under the condition of the spin and pseudospin
symmetry. Keywords: Spin and pseudospin symmetry; orbital dependency; Dirac
equation; Hulthen potential; Nikiforov-Uvarov Method.",1110.1225v1
2012-03-21,Persistent narrowing of nuclear-spin fluctuations in InAs quantum dots using laser excitation,"We demonstrate the suppression of nuclear spin fluctuations in an InAs
quantum dot and measure the timescales of the spin narrowing effect. By
initializing for tens of milliseconds with two continuous wave diode lasers,
fluctuations of the nuclear spins are suppressed via the hole assisted dynamic
nuclear polarization feedback mechanism. The fluctuation narrowed state
persists in the dark (absent light illumination) for well over one second even
in the presence of a varying electron charge and spin polarization. Enhancement
of the electron spin coherence time (T2*) is directly measured using coherent
dark state spectroscopy. By separating the calming of the nuclear spins in time
from the spin qubit operations, this method is much simpler than the spin echo
coherence recovery or dynamic decoupling schemes.",1203.4742v1
2012-08-27,Non-adiabatically driven electron in quantum wire with spin-orbit interaction,"An exact solution is derived for the wave function of an electron in a
semiconductor quantum wire with spin-orbit interaction and driven by external
time dependent harmonic confining potential. The formalism allows analytical
expressions for various quantities to be derived, such as spin and pseudo-spin
rotations, energy and occupation probabilities for excited states. It is
demonstrated how perfect spin and pseudo-spin flips can be achieved at high
frequencies of order \omega, the confining potential level spacing. By an
appropriately chosen driving term, spin manipulation can be exactly performed
far into the non-adiabatic regime. Implications for spin-polarised emission and
spin-dependent transport are also discussed.",1208.5359v1
2012-12-15,Transverse spin gradient functional for non-collinear spin density functional theory,"We present a novel functional for spin density functional theory aiming at
the description of non-collinear magnetic structures. The construction of the
functional employs the spin-spiral-wave state of the uniform electron gas as
reference system. We show that the functional depends on transverse gradients
of the spin magnetization, i.e., in contrast to the widely used local spin
density approximation, the functional is sensitive to local changes of the
direction of the spin magnetization. As a consequence the exchange-correlation
magnetic field is not parallel to the spin magnetization and a local
spin-torque is present in the ground state of the Kohn-Sham system. As a
proof-of-principle we apply the functional to a Chromium mono-layer in the
non-collinear ${120^{\circ}}$-N{\'e}el state.",1212.3658v2
2012-12-21,Next-to-next-to-leading order spin-orbit effects in the near-zone metric and precession equations of compact binaries,"We extend our previous work devoted to the computation of the
next-to-next-to-leading order spin-orbit correction (corresponding to 3.5PN
order) in the equations of motion of spinning compact binaries, by: (i)
Deriving the corresponding spin-orbit terms in the evolution equations for the
spins, the conserved integrals of the motion and the metric regularized at the
location of the particles (obtaining also the metric all-over the near zone but
with some lower precision); (ii) Performing the orbital reduction of the
precession equations, near-zone metric and conserved integrals to the center-
of-mass frame and then further assuming quasi-circular orbits (neglecting
gravitational radiation reaction). The results are systematically expressed in
terms of the spin variables with conserved Euclidean norm instead of the
original antisymmetric spin tensors of the pole-dipole formalism. This work
paves the way to the future computation of the next-to-next-to-leading order
spin-orbit terms in the gravitational-wave phasing of spinning compact
binaries.",1212.5520v2
2013-04-25,Spin blocker made of semiconductor double quantum well using the Rashba effect,"We propose a lateral spin-blockade device that uses an InGaAs/InAlAs double
quantum well (DQW), where the values of the Rashba spin-orbit parameter
$\alpha_{\rm R}$ are opposite in sign but equal in magnitude between the
constituent quantum wells (QW). By tuning the channel length of DQW and the
magnitude of the externally applied in-plane magnetic field, one can block the
transmission of one spin (e.g., spin-down) component, leading to a
spin-polarized current. Such a spin-blocking effect, brought about by wave
vector matching of the spin-split Fermi surfaces between the two QWs, paves the
way for a new scheme of spin-polarized electric current generation for future
spintronics applications based on semiconductor band engineering.",1304.6992v1
2013-10-23,Effect of Quantum Spin Fluctuation on Scalar Chiral Ordering in the Kondo Lattice Model on a Triangular Lattice,"Spin scalar chiral ordering gives rise to nontrivial topological characters
and peculiar transport properties. We here examine how quantum spin
fluctuations affect the spin scalar chiral ordering in itinerant electron
systems. We take the Kondo lattice model on a triangular lattice, and perform
the linear spin wave analysis in the Chern insulator phases with spin scalar
chiral ordering obtained in the case that the localized spins are classical. We
find that, although the quantum fluctuation destabilizes the spin scalar chiral
phase at 3/4 filling that originates from the perfect nesting of Fermi surface,
it retains the phase at 1/4 filling that is induced by an effective positive
biquadratic interaction. The reduction of the ordered magnetic moment by the
zero-point quantum fluctuation is considerably small, compared with those in
spin-only systems. The results suggest that the Chern insulator at 1/4 filling
remains robust under quantum fluctuations.",1310.6292v1
2013-12-27,Spin Transfer Torque and Electric Current in Helical Edge States in Quantum Spin Hall Devices,"We study the dynamics of a quantum spin Hall edge coupled to a magnet with
its own dynamics. Using spin transfer torque principles, we analyze the
interplay between spin currents in the edge state and dynamics of the axis of
the magnet, and draw parallels with circuit analogies. As a highlighting
feature, we show that while coupling to a magnet typically renders the edge
state insulating by opening a gap, in the presence of a small potential bias,
spin-transfer torque can restore perfect conductance by transferring angular
momentum to the magnet. In the presence of interactions within the edge state,
we employ a Luttinger liquid treatment to show that the edge, when subject to a
small voltage bias, tends to form a unique dynamic rotating spin wave state
that naturally couples into the dynamics of the magnet. We briefly discuss
realistic physical parameters and constraints for observing this interplay
between quantum spin Hall and spin-transfer torque physics.",1312.7303v1
2014-03-13,Coupling theory of emergent spin electromagnetic field and electromagnetic field,"In ferromagnetic metals, an effective electromagnetic field which couples to
conduction electron spin is induced by the sd exchange interaction. We
investigate how this effective field, spin electromagnetic field, interacts
with the ordinary electromagnetic field by deriving an effective Hamiltonian
based on the path-integral formalism. It turns out that the dominant coupling
term is the product of the electric field and the spin gauge field. This term
descrives the spin-transfer effect, as was pointed out before. The electric
field couples also to the spin electric field, but this contribution is smaller
than the spin-transfer contribution in the low frequency regime. The magnetic
field couples to the spin magnetic field, and this interaction suggests an
intriguing intrinsic mechanism of frustration in very weak metallic
ferromagnets under a uniform magnetic field. We also propose a voltage
generation mechanism due to a non-linear effect of non-monochromatic spin wave
excitation.",1403.3214v3
2014-04-21,Graphene with wedge disclination in the presence of intrinsic and Rashba spin orbit couplings,"In this article, the modified Kane-Mele Hamiltonian is derived for graphene
with wedge disclination and spin orbit couplings (intrinsic and Rashba). The
wedge disclination changes the flat lattice into the conical lattice and hence
modifies the spin orbit couplings. The Hamiltonian is exactly solved for the
intrinsic spin orbit interaction and perturbatively for the Rashba spin orbit
interaction. It is shown that there exists the Kramer's degenerate midgap
localized spin separated fluxon states around the defect. These zero energy
spin separated states occur at the external magnetic flux value
$\Phi\pm\Delta\Phi$. The external magnetic flux $\Phi$ is introduced to make
the wave-function periodic when the electron circulates around the defect. It
is found that this separation occurs due to the effect of the conical curvature
on the spin orbit coupling. Further, we find these results are robust to the
addition of the Rashba spin orbit interaction which is important for the
application to spintronics and nanoelectronics.",1404.5150v2
2014-09-09,Electron-spin dynamics in elliptically polarized light waves,"We investigate the coupling of the spin angular momentum of light beams with
elliptical polarization to the spin degree of freedom of free electrons. It is
shown that this coupling, which is of similar origin as the well-known
spin-orbit coupling, can lead to spin precession. The spin-precession frequency
is proportional to the product of the laser-field's intensity and its spin
density. The electron-spin dynamics is analyzed by employing exact numerical
methods as well as time-dependent perturbation theory based on the fully
relativistic Dirac equation and on the nonrelativistic Pauli equation that is
amended by a relativistic correction that accounts for the light's spin
density.",1409.2647v2
2014-09-17,Arbitrary Spin Galilean Oscillator,"The so-called Dirac oscillator was proposed as a modification of the free
Dirac equation which reproduces many of the properties of the simple harmonic
oscillator but accompanied by a strong spin-orbit coupling term. It has yet to
be extended successfully to the arbitrary spin S case primarily because of the
unwieldiness of general spin Lorentz invariant wave equations. It is shown here
using the formalism of totally symmetric multispinors that the Dirac oscillator
can, however, be made to accommodate spin by incorporating it into the
framework of Galilean relativity. This is done explicitly for spin zero and
spin one as special cases of the arbitrary spin result. For the general case it
is shown that the coefficient of the spin-orbit term has a 1/S behavior by
techniques which are virtually identical to those employed in the derivation of
the g-factor carried out over four decades ago.",1409.5101v1
2015-04-08,Spin Seebeck Power Conversion,"Spin caloritronics is the science and technology to control spin, charge, and
heat currents in magnetic nanostructures. The spin degree of freedom provides
new strategies for thermolelectric power generation that have not yet been
fully explored. After an elementary introduction into conventional
thermoelectrics and spintronics, we give a brief review of the physics of spin
caloritronics. We discuss spin-dependent thermoelectrics based on the the
two-current model in metallic magnets as well as the spin Seebeck and Peltier
effects that are based on spin wave excitations in ferromagnets. We derive
expressions for the efficiency and figure of merit ZT of several spin
caloritronic devices.",1504.02002v1
2015-04-20,Emergent topological properties in interacting one-dimensional systems with spin-orbit coupling,"We present analysis of a single channel interacting quantum wire problem in
the presence of spin-orbit interaction. The spin-orbit coupling breaks the
spin-rotational symmetry from SU(2) to U(1) and breaks inversion symmetry. The
low-energy theory is then a two band model with a difference of Fermi
velocities $\delta v$. Using bosonization and a two-loop renormalization group
procedure we show that electron-electron interactions can open a gap in the
spin sector of the theory when the interaction strength $U$ is smaller than
$\delta v$ in appropriate units. For repulsive interactions, the resulting
strong coupling phase is of the spin-density-wave type. We show that this phase
has peculiar emergent topological properties. The gapped spin sector behaves as
a topological insulator, with zero-energy edge modes with fractional spin. On
the other hand, the charge sector remains critical, meaning the entire system
is metallic. However, this bulk electron liquid as a whole exhibits properties
commonly associated with the one-dimensional edge states of two-dimensional
spin-Hall insulators, in particular, the conduction of $2e^2/h$ is robust
against nonmagnetic impurities.",1504.05016v2
2015-09-20,Spin-axion coupling,"We establish a new covariant phenomenological model, which describes an
influence of pseudoscalar (axion) field on spins of test massive particles. The
model includes general relativistic equations of particle motion and spin
evolution in background pseudoscalar (axion), electromagnetic and gravitational
fields. It describes both the direct spin-axion coupling of the gradient type
and indirect spin-axion interaction mediated by electromagnetic fields. Special
attention is paid to the direct spin-axion coupling caused by the gradient of
the pseudoscalar (axion) field. We show that it describes a spin precession,
when the pseudoscalar (axion) field is inhomogeneous and/or non-stationary.
Applications of the model, which correspond to the three types of four-vectors
attributed to the gradient of the pseudoscalar (axion) field (time-like,
space-like, and null), are considered in detail. These are the spin precessions
induced by relic cosmological axions, axions distributed around spherically
symmetric static objects, and axions in a gravitational wave field,
respectively. We discuss features of the obtained exact solutions and some
general properties of the axionically induced spin rotation.",1509.06058v2
2016-01-05,Dynamics of interacting fermions in spin-dependent potentials,"Recent experiments with dilute trapped Fermi gases observed that weak
interactions can drastically modify spin transport dynamics and give rise to
robust collective effects including global demagnetization, macroscopic spin
waves, spin segregation, and spin self-rephasing. In this work we develop a
framework for studying the dynamics of weakly interacting fermionic gases
following a spin-dependent change of the trapping potential which illuminates
the interplay between spin, motion, Fermi statistics, and interactions. The key
idea is the projection of the state of the system onto a set of lattice spin
models defined on the single-particle mode space. Collective phenomena,
including the global spreading of quantum correlations in real space, arise as
a consequence of the long-ranged character of the spin model couplings. This
approach achieves good agreement with prior measurements and suggests a number
of directions for future experiments.",1601.01004v3
2016-04-15,Determining the spin-orbit coupling via spin-polarized spectroscopy of magnetic impurities,"We study the spin-resolved spectral properties of the impurity states
associated to the presence of magnetic impurities in two-dimensional, as well
as one-dimensional systems with Rashba spin-orbit coupling. We focus on Shiba
bound states in superconducting materials, as well as on impurity states in
metallic systems. Using a combination of a numerical T-matrix approximation and
a direct analytical calculation of the bound state wave function, we compute
the local density of states (LDOS) together with its Fourier transform (FT). We
find that the FT of the spin-polarized LDOS, a quantity accessible via
spin-polarized STM, allows to accurately extract the strength of the spin-orbit
coupling. Also we confirm that the presence of magnetic impurities is strictly
necessary for such measurement, and that non-spin-polarized experiments cannot
have access to the value of the spin-orbit coupling.",1604.04623v3
2016-07-19,Electrical detection of spiral spin structures in Pt|Cu_2OSeO_3 heterostructures,"The interaction between the itinerant spins in metals and localized spins in
magnetic insulators thus far has only been explored in collinear spin systems,
such as garnets. Here, we report the spin-Hall magnetoresistance (SMR)
sensitive to the surface magnetization of the spin-spiral material, Cu_2OSeO_3.
We experimentally demonstrate that the angular dependence of the SMR changes
drastically at the transition between the helical spiral and the conical spiral
phases. Furthermore, the sign and magnitude of the SMR in the conical spiral
state are controlled by the cone angle. We show that this complex behaviour can
be qualitatively explained within the SMR theory initially developed for
collinear magnets. In addition, we studied the spin Seebeck effect (SSE), which
is sensitive to the bulk magnetization. It originates from the conversion of
thermally excited low-energy spin waves in the magnet, known as magnons, into
the spin current in the adjacent metal contact (Pt). The SSE displays
unconventional behavior where not only the magnitude but also the phase of the
SSE vary with the applied magnetic field.",1607.05630v1
2017-08-28,Observation of quantum spin noise in a 1D light-atoms quantum interface,"We observe collective quantum spin states of an ensemble of atoms in a
one-dimensional light-atom interface. Strings of hundreds of cesium atoms
trapped in the evanescent fiel of a tapered nanofiber are prepared in a
coherent spin state, a superposition of the two clock states. A weak quantum
nondemolition measurement of one projection of the collective spin is performed
using a detuned probe dispersively coupled to the collective atomic observable,
followed by a strong destructive measurement of the same spin projection. For
the coherent spin state we achieve the value of the quantum projection noise 40
dB above the detection noise, well above the 3 dB required for reconstruction
of the negative Wigner function of nonclassical states. We analyze the effects
of strong spatial inhomogeneity inherent to atoms trapped and probed by the
evanescent waves. We furthermore study temporal dynamics of quantum
fluctuations relevant for measurement-induced spin squeezing and assess the
impact of thermal atomic motion. This work paves the road towards observation
of spin squeezed and entangled states and many-body interactions in 1D spin
ensembles.",1708.08387v2
2017-11-20,Precessional dynamics of black hole triples: binary mergers with near-zero effective spin,"The binary black hole mergers detected by Advanced LIGO/Virgo have shown no
evidence of large black hole spins. However, because LIGO/Virgo best measures
the effective combination of the two spins along the orbital angular momentum
($\chi_{\rm eff}$), it is difficult to distinguish between binaries with
slowly-spinning black holes and binaries with spins lying in the orbital plane.
Here, we study the spin dynamics for binaries with a distant black hole
companion. For spins initially aligned with the orbital angular momentum of the
binary, we find that $\chi_{\rm eff}$ ""freezes"" near zero as the orbit decays
through the emission of gravitational waves. Through a population study, we
show that this process predominantly leads to merging black hole binaries with
near-zero $\chi_{\rm eff}$. We conclude that if the detected black hole
binaries were formed in triples, then this would explain their low $\chi_{\rm
eff}$ without the need to invoke near-zero spins or initially large spin-orbit
angles.",1711.07142v2
2018-09-20,Entangling Distant Spin qubits via a Magnetic Domain Wall,"The scalability of quantum networks based on solid-state spin qubits is
hampered by the short range of natural spin-spin interactions. Here, we propose
a scheme to entangle distant spin qubits via the soft modes of an
antiferromagnetic domain wall (DW). As spin qubits, we focus on quantum
impurities (QI's) placed in the vicinity of an insulating antiferromagnetic
thin film. The low-energy modes harbored by the DW are embedded in the
antiferromagnetic bulk, whose intrinsic spin-wave dynamics have a gap that can
exceed the THz range. By setting the QI frequency and the temperature well
within the bulk gap, we focus on the dipolar interaction between the QI and two
soft modes localized at the DW. One is a string-like mode associated with
transverse displacements of the DW position, while the dynamics of the other,
corresponding to planar rotations of the Neel order parameter, constitute a
spin superfluid. By choosing the geometry in which the QI does not couple to
the string mode, we use an external magnetic field to control the gap of the
spin superfluid and the qubit-qubit coupling it engenders. We suggest that a
tunable micron-range coherent coupling between qubits can be established using
common antiferromagnetic materials.",1809.07785v1
2018-10-29,Superconductivity in the Hubbard model: a hidden-order diagnostics from the Luther-Emery phase on ladders,"Short-range antiferromagnetic correlations are known to open a spin gap in
the repulsive Hubbard model on ladders with $M$ legs, when $M$ is even. We show
that the spin gap originates from the formation of correlated pairs of
electrons with opposite spin, captured by the hidden ordering of a spin-parity
operator. Since both spin gap and parity vanish in the two-dimensional limit,
we introduce the fractional generalization of spin parity and prove that it
remains finite in the thermodynamic limit. Our results are based upon
variational wave functions and Monte Carlo calculations: performing a finite
size-scaling analysis with growing $M$, we show that the doping region where
the parity is finite coincides with the range in which superconductivity is
observed in two spatial dimensions. Our observations support the idea that
superconductivity emerges out of spin gapped phases on ladders, driven by a
spin-pairing mechanism, in which the ordering is conveniently captured by the
finiteness of the fractional spin-parity operator.",1810.12268v2
2014-06-05,Electric control of spin injection into a ferroelectric semiconductor,"Electric-field control of spin-dependent properties has become one of the
most attractive phenomena in modern materials research due the promise of new
device functionalities. One of the paradigms in this approach is to
electrically toggle the spin polarization of carriers injected into a
semiconductor using ferroelectric polarization as a control parameter. Using
first-principles density functional calculations, we explore the effect of
ferroelectric polarization of electron-doped BaTiO3 (n-BaTiO3) on the
spin-polarized transmission across the SrRuO3/n-BaTiO3 (001) interface. Our
study reveals that the interface transmission is negatively spin-polarized and
that ferroelectric polarization reversal leads to a change in the transport
spin polarization from -65% to -98%. We show that this effect stems from the
large difference in Fermi wave vectors between up- and down-spins in
ferromagnetic SrRuO3 and a change in the transport regime driven by
ferroelectric polarization switching. The predicted sizeable change in the spin
polarization provides a non-volatile mechanism to electrically control spin
injection in semiconductor-based spintronics devices.",1406.1434v1
2020-03-14,Position and spin in relativistic quantum mechanics,"The problem of the position and spin in relativistic quantum mechanics is
analyzed in detail. It is definitively shown that the position and spin
operators in the Foldy-Wouthuysen representation (but not in the Dirac one) are
quantum-mechanical counterparts of the classical position and spin variables.
The probabilistic interpretation is valid only for Foldy-Wouthuysen wave
functions. The relativistic spin operators are discussed. The spin-orbit
interaction does not exist for a free particle if the conventional operators of
the orbital angular momentum and the rest-frame spin are used. Alternative
definitions of the orbital angular momentum and the spin are based on
noncommutative geometry, do not satisfy standard commutation relations, and can
allow the spin-orbit interaction.",2003.06572v2
2021-02-18,Spin distribution of binary black holes formed in open clusters,"We performed direct N-body simulations of open clusters with four different
metallicities. To investigate the effective spins of merging binary black holes
(BBHs) originated from these open clusters, we calculated the spin evolution of
Wolf-Rayet (WR) stars with close companion stars (BBH progenitors), taking into
account stellar wind mass loss and tidal spin-up of the WR stars. We found that
BBH progenitors with smaller semi-major axes evolve to merging BBHs with
greater effective spins because of strong tidal forces. In the local Universe,
about 16% of merging BBHs get effective spins larger than 0.1 even if BHs and
their progenitors do not get spin angular momenta other than tidal forces
exerted by their companion stars. If we assume that WR stars have flat and
isotropic distribution of dimensionless spins just after common envelope
phases, the effective spin distribution of merging BBHs is similar to that
inferred from gravitational wave observations with LIGO and Virgo.",2102.09323v1
2021-10-21,Extrinsic spin angular momentum carried by plasmonic vortex in terahertz cylindrical corrugated waveguide,"An electromagnetic surface wave carrying orbital angular momentum (AM) is
called plasmonic vortex that also carries spin AM originating from evanescent
field. In this study, spin and orbital AM of plasmonic vortex in a terahertz
cylindrical corrugated waveguide (CCW) are analyzed. We report the extrinsic
spin AM of the plasmonic vortex for the first time. The extrinsic spin AM is
produced by the rotation of the polarization of the plasmonic vortex whose
rotation axis is positioned at the vicinity of the CCW wall. The extrinsic spin
AM depends on the intrinsic orbital AM and radius of CCW. The plasmonic vortex
with sufficiently large orbital AM carries large spin AM per photon. This large
extrinsic spin AM expands degree of freedom of the spin AM and would be applied
to various terahertz technologies.",2110.10893v1
2021-05-20,Spin-orbital-momentum locking under odd-parity magnetic quadrupole ordering,"Odd-parity magnetic and magnetic toroidal multipoles in the absence of both
spatial-inversion and time-reversal symmetries are sources of multiferroic and
nonreciprocal optical phenomena. We investigate electronic states caused by an
emergent odd-parity magnetic quadrupole (MQ) as a representative example of
magnetic odd-parity multipoles. It is shown that spontaneous ordering of the MQ
leads to an antisymmetric spin-orbital polarization in momentum space, which
corresponds to a spin-orbital momentum locking at each wave vector. By symmetry
argument, we show that the orbital or sublattice degree of freedom is
indispensable to give rise to the spin-orbital momentum locking. We demonstrate
how the electronic band structures are modulated by the MQ ordering in the
three-orbital system, in which the MQ is activated by the spin-dependent
hybridization between the orbitals with different spatial parities. The
spin-orbital momentum locking is related with the microscopic origin of
cross-correlated phenomena, e.g., the magnetic-field-induced symmetric and
antisymmetric spin polarization in the band structure, the current-induced
distortion, and the magnetoelectric effect. We also discuss similar
spin-orbital momentum locking in antiferromagnet where the MQ degree of freedom
is activated through the antiferromagnetic spin structure in a sublattice
system.",2105.09444v1
2021-05-28,Spin-orbit interactions of transverse sound,"Spin-orbit interactions (SOIs) endow light with intriguing properties and
applications such as photonic spin-Hall effects and spin-dependent vortex
generations. However, it is counterintuitive that SOIs can exist for sound,
which is a longitudinal wave that carries no intrinsic spin. Here, we
theoretically and experimentally demonstrate that airborne sound can possess
artificial transversality in an acoustic micropolar metamaterial and thus carry
both spin and orbital angular momentum. This enables the realization of
acoustic SOIs with rich phenomena beyond those in conventional acoustic
systems. We demonstrate that acoustic activity of the metamaterial can induce
coupling between the spin and linear crystal momentum k, which leads to
negative refraction of the transverse sound. In addition, we show that the
scattering of the transverse sound by a dipole particle can generate
spin-dependent acoustic vortices via the geometric phase effect. The acoustic
SOIs can provide new perspectives and functionalities for sound manipulations
beyond the conventional scalar degree of freedom and may open an avenue to the
development of spin-orbit acoustics.",2105.13558v1
2021-09-16,Ground States of Heisenberg Spin Clusters from Projected Hartree-Fock Theory,"We apply Projected Hartree-Fock theory (PHF) for approximating ground states
of Heisenberg spin clusters. Spin-rotational, point-group and
complex-conjugation symmetry are variationally restored from a broken-symmetry
mean-field reference, where the latter corresponds to a product of local spin
states. A fermionic formulation of the Heisenberg model furnishes a conceptual
connection to PHF applications in quantum chemistry and detailed equations for
a self-consistent field optimization of the reference state are provided.
Different PHF variants are benchmarked for ground-state energies and spin-pair
correlation functions of antiferromagnetic spin rings and three different
polyhedra, with various values of the local spin-quantum number s. The low
computational cost and the compact wave-function representation make PHF a
promising complement to existing approaches for ground states of molecular spin
clusters, particularly for large s and moderately large N. The present work may
also motivate future explorations of more accurate post-PHF methods for
Heisenberg spin clusters.",2109.08041v1
2021-12-21,Spin accumulation without spin current,"The spin Hall (SH) effect is a phenomenon in which the spin current flows
perpendicular to an applied electric field and causes the spin accumulation at
the boundaries. However, in the presence of spin-orbit couplings, the spin
current is not well defined. Here, we calculate the spin response to an
electric-field gradient, which naturally appears at the boundaries. We derive a
generic formula using the Bloch wave functions and the phenomenological
relaxation time. We also calculate the response for the uniform Rashba model
with $\delta$-function nonmagnetic disorder within the first-order Born
approximation and corresponding vertex corrections. We find the nonzero spin
accumulation, although the SH conductivity exactly vanishes.",2112.11043v3
2022-04-11,Curvilinear spin-wave dynamics beyond the thin-shell approximation: Magnetic nanotubes as a case study,"Surface curvature of magnetic systems can lead to many static and dynamic
effects which are not present in flat systems of the same material. These
emergent magnetochiral effects can lead to frequency nonreciprocity of spin
waves, which has been shown to be a bulk effect of dipolar origin and is
related to a curvature-induced symmetry breaking in the magnetic volume
charges. So far, such effects have been investigated theoretically mostly for
thin shells, where the spatial profiles of the spin waves can be assumed to be
homogeneous along the thickness. Here, using a finite-element dynamic-matrix
approach, we investigate the transition of the spin-wave spectrum from thin to
thick curvilinear shells, at the example of magnetic nanotubes in the vortex
state. With increasing thickness, we observe the appearance of higher-order
radial modes which are strongly hybridized and resemble the
perpendicular-standing-waves (PSSWs) in flat films. Along with an increasing
dispersion asymmetry, we uncover the curvature-induced non-reciprocity of the
mode profiles. This is explained in a very simple picture general for thick
curvilinear shells, considering the inhomogeneity of the emergent geometric
volume charges along the thickness of the shell. Such curvature-induced
mode-profile asymmetry also leads to non-reciprocal hybridization which can
facilitate unidirectional spin-wave propagation. With that, we also show how
curvature allows for nonlinear three-wave splitting of a higher-order radial
mode into secondary modes which can also propagate unidirectionally. We believe
that our study provides a significant contribution to the understanding of the
spin-wave dynamics in curvilinear magnetic systems, but also advertises these
for novel magnonic applications.",2204.05065v1
2004-08-26,"Orbital ordering, Jahn-Teller distortion, and resonant x-ray scattering in KCuF3","The orbital, lattice, and spin ordering phenomena in KCuF3 are investigated
by means of LDA+U calculations, based on ab-initio pseudopotentials.We examine
the Cu-3d orbital ordering and the associated Jahn-Teller distortion in several
different spin-ordered structures of KCuF3. The ground state is correctly
predicted to be an A-type antiferromagnetic structure, and the calculated
Jahn-Teller distortion agrees also well with experiment. Concerning the orbital
ordering, we find that even for a highly ionic compound such as KCuF3, the
orbital-order parameter is significantly reduced with respect to its nominal
value due to Cu(3d)--F(2p) hybridization. We also calculate the Cu K-edge
resonant x-ray scattering spectra for Bragg reflections associated with orbital
order. Consistent with previous studies, we find that the resonant signal is
dominated by the structural anisotropy in the distribution of the F neighbors
of the resonant Cu atom, and that the Cu-3d orbital ordering has only a minor
influence on the spectra. Our LDA+U results, however, also indicate that a
change in the magnetic structure has a small influence on the Jahn-Teller
distortion, and hence on the resonant spectrum, in the conventional
(room-temperature) crystallographic structure of KCuF3. This may indicate that
the large change observed experimentally in the resonant signal near the N\'eel
temperature is related to a low-temperature structural transformation in KCuF3.",0408568v1
2013-08-01,Electronic superlattice revealed by resonant scattering from random impurities in Sr3Ru2O7,"Resonant elastic x-ray scattering (REXS) is an exquisite element-sensitive
tool for the study of subtle charge, orbital, and spin superlattice orders
driven by the valence electrons, which therefore escape detection in
conventional x-ray diffraction (XRD). Although the power of REXS has been
demonstrated by numerous studies of complex oxides performed in the soft x-ray
regime, the cross section and photon wavelength of the material-specific
elemental absorption edges ultimately set the limit to the smallest
superlattice amplitude and periodicity one can probe. Here we show -- with
simulations and REXS on Mn-substituted Sr$_3$Ru$_2$O$_7$ -- that these
limitations can be overcome by performing resonant scattering experiments at
the absorption edge of a suitably-chosen, dilute impurity. This establishes
that -- in analogy with impurity-based methods used in electron-spin-resonance,
nuclear-magnetic resonance, and M\""ossbauer spectroscopy -- randomly
distributed impurities can serve as a non-invasive, but now momentum-dependent
probe, greatly extending the applicability of resonant x-ray scattering
techniques.",1308.0185v1
2013-08-02,Strong coupling behavior of the neutron resonance mode in unconventional superconductors,"We analyze whether and how the neutron resonance mode in unconventional
superconductors is affected by higher order corrections in the coupling between
spin excitations and fermionic quasiparticles and find that in general such
corrections cannot be ignored. In particular, we find that in two spatial
dimensions (d=2) the corrections are of same order as the leading, weak
coupling contributions demonstrating that the neutron resonance mode in
unconventional superconductors is a strong coupling phenomenon. The origin of
this behavior lies in the quantum-critical nature of the low energy spin
dynamics in the superconducting state and the feedback of the resonance mode
onto the fermionic excitations. While quantum critical fluctuations occur in
any dimensionality smaller than the upper critical dimension d_{uc}=3, they can
be analyzed in a controlled fashion by means of the \epsilon-expansion
(\epsilon =3-d), such that the leading corrections to the resonance mode
position are small. Regardless of the strong coupling nature of the resonance
mode we show that it emerges only if the phase of the superconducting gap
function varies on the Fermi surface, making it a powerful tool to investigate
the microscopic structure of the pair condensate.",1308.0427v3
2016-04-25,Frequency-based nanoparticle sensing over large field ranges using the ferromagnetic resonances of a magnetic nanodisc,"Using finite element micromagnetic simulations, we study how resonant
magnetisation dynamics in thin magnetic discs with perpendicular anisotropy are
influenced by magnetostatic coupling to a magnetic nanoparticle. We identify
resonant modes within the disc using direct magnetic eigenmode calculations and
study how their frequencies and profiles are changed by the nanoparticle's
stray magnetic field. We demonstrate that particles can generate shifts in the
resonant frequency of the disc's fundamental mode which exceed resonance
linewidths in recently studied spin torque oscillator devices. Importantly, it
is shown that the simulated shifts can be maintained over large field ranges
(here up to 1T). This is because the resonant dynamics (the basis of
nanoparticle detection here) respond directly to the nanoparticle stray field,
i.e. detection does not rely on nanoparticle-induced changes to the magnetic
ground state of the disk. A consequence of this is that in the case of small
disc-particle separations, sensitivities to the particle are highly mode- and
particle-position-dependent, with frequency shifts being maximised when the
intense stray field localised directly beneath the particle can act on a large
proportion of the disc's spins that are undergoing high amplitude precession.",1604.07277v2
2023-04-27,Asymmetric Chiral Coupling in a Topological Resonator,"Chiral light-matter interactions supported by topological edge modes at the
interface of valley photonic crystals provide a robust method to implement the
unidirectional spin transfer. The valley topological photonic crystals possess
a pair of counterpropagating edge modes. The edge modes are robust against the
sharp bend of $60^{\circ}$ and $120^{\circ}$, which can form a resonator with
whispering gallery modes. Here, we demonstrate the asymmetric emission of
chiral coupling from single quantum dots in a topological resonator by tuning
the coupling between a quantum emitter and a resonator mode. Under a magnetic
field in Faraday configuration, the exciton state from a single quantum dot
splits into two exciton spin states with opposite circularly polarized
emissions due to Zeeman effect. Two branches of the quantum dot emissions
couple to a resonator mode in different degrees, resulting in an asymmetric
chiral emission. Without the demanding of site-control of quantum emitters for
chiral quantum optics, an extra degree of freedom to tune the chiral contrast
with a topological resonator could be useful for the development of on-chip
integrated photonic circuits.",2304.13904v1
2023-09-19,Capacitive crosstalk in gate-based dispersive sensing of spin qubits,"In gate-based dispersive sensing, the response of a resonator attached to a
quantum dot gate is detected by a reflected radio-frequency signal. This
enables fast readout of spin qubits and tune up of arrays of quantum dots, but
comes at the expense of increased susceptibility to crosstalk, as the resonator
can amplify spurious signals and induce fluctuations in the quantum dot
potential. We attach tank circuits with superconducting NbN inductors and
internal quality factors $Q_{\mathrm{i}}$>1000 to the interdot barrier gate of
silicon double quantum dot devices. Measuring the interdot transition in
transport, we quantify radio-frequency crosstalk that results in a ring-up of
the resonator when neighbouring plunger gates are driven with frequency
components matching the resonator frequency. This effect complicates qubit
operation and scales with the loaded quality factor of the resonator, the
mutual capacitance between device gate electrodes, and with the inverse of the
parasitic capacitance to ground. Setting qubit frequencies below the resonator
frequency is expected to substantially suppress this type of crosstalk.",2309.10473v1
2024-01-26,Low loss hybrid Nb/Au superconducting resonators for quantum circuit applications,"Superconducting resonators play a crucial role in developing forthcoming
quantum computing schemes. The complete integration of molecular spin-based
quantum bits with superconducting resonators still requires further
developments, notably in maintaining low-loss resonances and high quality
factors. In this work, we have developed a superconducting device combining a
niobium (Nb) circuit with a 10 nm gold (Au) capping layer, which supports low
microwave losses and enables new functionalities such as the integration of
magnetic molecules into solid-state devices. Our investigation across a wide
temperature and driving power range reveals that adding the Au layer reduces
the density of two-level system (TLS) defects present in the device. Moreover,
the presence of the thin Au layer induces a higher kinetic inductance at low
temperatures, leading to enhanced responsivity. Cryogenic characterization
confirms the good performance of the device, allowing these resonators to serve
as platforms for hybrid devices involving molecular spin qubits/gates where the
gold can anchor alkyl thiol groups to form self-assembled monolayers. Our
findings suggest the potential of Nb/Au lumped element resonators (LERs) as
versatile and promising tools for advancing superconducting quantum
technologies and the integration of quantum functionalities into solid-state
devices.",2401.14764v1
2024-01-28,Long-Term Evolution of the Saturnian System,"Here we present the current state of knowledge on the long-term evolution of
Saturn's moon system due to tides within Saturn. First we provide some
background on tidal evolution, orbital resonances and satellite tides. Then we
address in detail some of the present and past orbital resonances between
Saturn's moons (including the Enceladus-Dione and Titan-Hyperion resonances)
and what they can tell us about the evolution of the system. We also present
the current state of knowledge on the spin-axis dynamics of Saturn: we discuss
arguments for a (past or current) secular resonance of Saturn's spin precession
with planetary orbits, and explain the links of this resonance to the tidal
evolution of Titan and a possible recent cataclysm in the Saturnian system. We
also address how the moons' orbital evolution, including resonances, affects
the evolution of their interiors. Finally, we summarize the state of knowledge
about the Saturnian system's long-term evolution and discuss prospects for
future progress.",2401.15797v1
2001-10-18,Dominant mode in the cuprates: electronic vs. phononic scenario,"We make the case for an electronic origin of the strong mode, recently seen
in ARPES experiments, and, in this regard, further discuss the physics of the
spin resonance peak.",0110368v2
2002-11-08,"Comment on ""Correlation of Tunneling Spectra in Bi2212 with the Resonance Spin Excitation""","The interpretation of tunneling data in a recent Letter by Zasadzinski et al.
is incorrect.",0211148v2
2002-10-31,A Strong Electroweak Sector at Future Colliders,"A brief overview of the production at future colliders of two new triplets of
spin one resonances from a strong electroweak breaking is presented.",0210438v1
2007-05-08,Controllability of the coupled spin-half harmonic oscillator system,"We present a control-theoretic analysis of the system consisting of a
two-level atom coupled with a quantum harmonic oscillator. We show that by
applying external fields with just two resonant frequencies, any desired
unitary operator can be generated.",0705.1055v1
2008-08-26,Magnetic field modification of ultracold molecule-molecule collisions,"We present an accurate quantum mechanical study of molecule-molecule
collisions in the presence of a magnetic field. The work focusses on the
analysis of elastic scattering and spin relaxation in collisions of
O2(3Sigma_g) molecules at cold (~0.1 K) and ultracold (~10^{-6} K)
temperatures. Our calculations show that magnetic spin relaxation in
molecule-molecule collisions is extremely efficient except at magnetic fields
below 1 mT. The rate constant for spin relaxation at T=0.1 K and a magnetic
field of 0.1 T is found to be as large as 6.1 x 10^{-11} cm3/s. The magnetic
field dependence of elastic and inelastic scattering cross sections at
ultracold temperatures is dominated by a manifold of Feshbach resonances with
the density of ~100 resonances per Tesla for collisions of molecules in the
absolute ground state. This suggests that the scattering length of ultracold
molecules in the absolute ground state can be effectively tuned in a very wide
range of magnetic fields. Our calculations demonstrate that the number and
properties of the magnetic Feshbach resonances are dramatically different for
molecules in the absolute ground and excited spin states. The density of
Feshbach resonances for molecule-molecule scattering in the low-field-seeking
Zeeman state is reduced by a factor of 10.",0808.3592v2
2009-04-30,Spin and model identification of Z' bosons at the LHC,"Heavy resonances appearing in the clean Drell-Yan channel may be the first
new physics to be observed at the proton-proton CERN LHC. If a new resonance is
discovered at the LHC as a peak in the dilepton invariant mass distribution,
the characterization of its spin and couplings will proceed via measuring
production rates and angular distributions of the decay products. We discuss
the discrimination of the spin-1 of Z' representative models (Z'_{SSM},
Z'_{psi}, Z'_{eta}, Z'_{chi}, Z'_{LR}, and Z'_{ALR}) against the
Randall-Sundrum graviton resonance (spin-2) and a spin-0 resonance (sneutrino)
with the same mass and producing the same number of events under the observed
peak. To assess the range of the Z' mass where the spin determination can be
performed to a given confidence level, we focus on the angular distributions of
the Drell-Yan leptons, in particular we use as a basic observable an
angular-integrated center-edge asymmetry, A_{CE}. The spin of a heavy Z' gauge
boson can be established with A_{CE} up to M_{Z'} \simeq 3.0 TeV, for an
integrated luminosity of 100 fb^{-1}, or minimal number of events around 110.
We also examine the distinguishability of the considered Z' models from one
another, once the spin-1 has been established, using the total dilepton
production cross section. With some assumption, one might be able to
distinguish among these Z' models at 95% C.L. up to M_{Z'} \simeq 2.1 TeV.",0904.4857v1
2010-08-27,Spin-transfer-torque resonant switching and injection locking in presence of a weak external microwave field for spin valves with perpendicular materials,"The effects of a weak microwave field in the magnetization dynamics driven by
spin-transfer-torque in spin-valves with perpendicular materials have been
systematically studied by means of full micromagnetic simulations. In the
system we studied, depending on the working point (bias field and current) in
the dynamical stability diagram, we observe either resonant switching and
injection locking. The resonant switching, observed in the switching region,
occurs when the field frequency is approaching the frequency of the main
pre-switching mode giving rise to an asymmetric power distribution of that mode
in the sectional area of the free layer. At the resonant frequency, the
switching time is weakly dependent on the relative phase between the instant
when the current pulse is applied and the microwave field. The injection
locking, observed in the dynamical region, is characterized by the following
properties: (i) a locking bandwidth which is linearly dependent on the force
locking, and (ii) a locking for integer harmonics of the self-oscillation
frequency. We compare our numerical results with analytical theory for
non-autonomous non-linear system obtaining a good agreement in the current
region where the oscillation frequency and output power are characterized from
a linear relationship.",1008.4746v1
2013-02-27,Hidden charm N and Delta resonances with heavy-quark symmetry,"We develop a model to describe odd parity baryon resonances generated
dynamically through a unitary baryon-meson coupled-channels approach. The
scheme applies to channels with light and/or heavy quark content. Distinct
features of the model are that, i) the interaction is an S-wave contact one,
ii) it reduces to the SU(3) Weinberg-Tomozawa Hamiltonian when light
pseudoscalar mesons are involved, thus, respecting chiral symmetry, iii)
spin-flavor in preserved in the light quark sector, and iv) heavy quark spin
symmetry is fulfilled in the heavy quark sector. In particular, baryon-meson
states with different content in c or in c-bar do not mix. The model is a
minimal one and it contains no free parameters. In this work, we focus on
baryon resonances with hidden-charm (at least one c-bar and one c quarks). We
analyze several possible sectors and, for the sector with zero net charm, we
write down the most general Lagrangian consistent with SU(3) and heavy quark
spin symmetry. We explicitly study the N and Delta states, which are produced
from the S-wave interaction of pseudoscalar and vector mesons with 1/2+ and
3/2+ baryons within the charmless and strangeless hidden charm sector. We
predict seven odd parity N-like and five Delta-like states with masses around 4
GeV, most of them as bound states. These states form heavy-quark spin
multiplets, which are almost degenerate in mass. The predicted new resonances
definitely cannot be accommodated by quark models with three constituent quarks
and they might be looked for in the forthcoming PANDA experiment at the future
FAIR facility.",1302.6938v1
2017-02-17,Quantum dimer models emerging from large-spin ultracold atoms,"We propose an experimental protocol for using cold atoms to create and probe
quantum dimer models, thereby exploring the Pauling-Anderson vision of a
macroscopic collection of resonating bonds. This process can allow the study of
exotic crystalline phases, fractionalization, topological spin liquids, and the
relationship between resonating dimers and superconductivity subjects which
have been challenging to address in solid-state experiments. Our key technical
development is considering the action of an off-resonant photoassociation laser
on large spin atoms localized at the sites of a deep optical lattice. The
resulting superexchange interaction favors nearest-neighbor singlets. We derive
an effective Hamiltonian in terms of these dimer degrees of freedom, finding
that it is similar to well-known quantum dimer models, which boast a rich
variety of valence bond crystal and spin liquid phases. We numerically study
the ground state, explain how to tune the parameters, and develop a protocol to
directly measure the dimers and their resonating patterns.",1702.05514v3
2017-10-10,Magnetic and superconducting properties on S-type single-crystal CeCu$_2$Si$_2$ probed by $^{63}$Cu nuclear magnetic resonance and nuclear quadrupole resonance,"We have performed $^{63}$Cu nuclear magnetic resonance/nuclear quadrupole
resonance measurements to investigate the magnetic and superconducting (SC)
properties on a ""superconductivity dominant"" ($S$-type) single crystal of
CeCu$_2$Si$_2$. Although the development of antiferromagnetic (AFM)
fluctuations down to 1~K indicated that the AFM criticality was close, Korringa
behavior was observed below 0.8~K, and no magnetic anomaly was observed above
$T_{\rm c} \sim$ 0.6 K. These behaviors were expected in $S$-type
CeCu$_2$Si$_2$. The temperature dependence of the nuclear spin-lattice
relaxation rate $1/T_1$ at zero field was almost identical to that in the
previous polycrystalline samples down to 130~mK, but the temperature dependence
deviated downward below 120~mK. In fact, $1/T_1$ in the SC state could be
fitted with the two-gap $s_{\pm}$-wave rather than the two-gap $s_{++}$-wave
model down to 90~mK. Under magnetic fields, the spin susceptibility in both
directions clearly decreased below $T_{\rm c}$, indicative of the formation of
spin singlet pairing. The residual part of the spin susceptibility was
understood by the field-induced residual density of states evaluated from
$1/T_1T$, which was ascribed to the effect of the vortex cores. No magnetic
anomaly was observed above the upper critical field $H_{c2}$, but the
development of AFM fluctuations was observed, indicating that superconductivity
was realized in strong AFM fluctuations.",1710.03364v1
2017-10-24,Hyperfine interactions of $\text{Er}^{3+}$ ions in $\text{Y}_2\text{SiO}_{5}$: electron paramagnetic resonance in a tunable microwave cavity,"The hyperfine structure of the ground state of erbium doped yttrium
orthosilicate is analyzed with the use of electron paramagnetic resonance
experiments in a tunable microwave resonator. This work was prompted by the
disagreement between the measurements made in zero magnetic field [Phys. Rev.
B, 94, 075117, (2016)] and a previously published spin Hamiltonian, which is
derived from standard EPR measurements at 9.5 GHz [Phys. Rev. B, 74, 214409,
(2006)].
  The ability to vary magnetic field strength, resonator frequency, and the
orientation of our sample enabled us to monitor how the frequencies of
hyperfine transitions change as a function of a vector magnetic field. Compared
to [Phys. Rev. B, 74, 214409, (2006)], we arrived at a different set of spin
Hamiltonian parameters, which are also broadly consistent with their data. We
discuss the reliability of our new spin Hamiltonian parameters to make
predictions outside the magnetic field and frequency regimes of our data. We
also discuss why it proved to be difficult to determine spin Hamiltonian
parameters for this material, and present data collection strategies that
improve the model reliability.",1710.09014v2
2017-10-30,Temperature and polarization dependence of low-energy magnetic fluctuations in nearly-optimal-doped NaFe$_{0.9785}$Co$_{0.0215}$As,"We use unpolarized and polarized neutron scattering to study the temperature
and polarization dependence of low-energy magnetic fluctuations in
nearly-optimal-doped NaFe$_{0.9785}$Co$_{0.0215}$As, with coexisting
superconductivity ($T_{\rm c}\approx19$ K) and weak antiferromagnetic order
($T_{\rm N}\approx30$ K, ordered moment $\approx0.02$ $\mu_{\rm B}$/Fe). A
single spin resonance mode with intensity tracking the superconducting order
parameter is observed, although energy of the mode only softens slightly on
approaching $T_{\rm c}$. Polarized neutron scattering reveals that the single
resonance is mostly isotropic in spin space, similar to overdoped
NaFe$_{0.935}$Co$_{0.045}$As but different from optimal electron-, hole-, and
isovalent-doped BaFe$_2$As$_2$ compounds, all featuring an additional prominent
anisotropic component. Spin anisotropy in NaFe$_{0.9785}$Co$_{0.0215}$As is
instead present at energies below the resonance, which becomes partially gapped
below $T_{\rm c}$, similar to the situation in optimal-doped
YBa$_2$Cu$_3$O$_{6.9}$. Our results indicate that anisotropic spin fluctuations
in NaFe$_{1-x}$Co$_x$As appear in the form of a resonance in the underdoped
regime, become partially gapped below $T_{\rm c}$ near optimal doping and
disappear in overdoped compounds.",1710.11083v1
2022-02-15,Evidence for a spinon Kondo effect in cobalt atoms on single-layer 1T-TaSe$_2$,"Quantum spin liquids (QSLs) are highly entangled, disordered magnetic states
that arise in frustrated Mott insulators and host exotic fractional excitations
such as spinons and chargons. Despite being charge insulators some QSLs are
predicted to exhibit gapless itinerant spinons that yield metallic behavior in
the spin channel. We have deposited isolated magnetic atoms onto single-layer
(SL) 1T-TaSe$_2$, a gapless QSL candidate, to experimentally probe how
itinerant spinons couple to impurity spin centers. Using scanning tunneling
spectroscopy we observe the emergence of new, impurity-induced resonance peaks
at the 1T-TaSe$_2$ Hubbard band edges when cobalt adatoms are positioned to
have maximal spatial overlap with the Hubbard band charge distribution. These
resonance peaks disappear when the spatial overlap is reduced or when the
magnetic impurities are replaced with non-magnetic impurities. Theoretical
simulations using a modified Anderson impurity model integrated with a gapless
quantum spin liquid show that these resonance peaks are consistent with a Kondo
resonance induced by spinons combined with spinon-chargon binding effects that
arise due to QSL gauge-field fluctuations.",2202.07224v1
2023-11-07,Coupling nitrogen-vacancy centre spins in diamond to a grape dimer,"Two grapes irradiated inside a microwave (MW) oven typically produce a series
of sparks and can ignite a violent plasma. The underlying cause of the plasma
has been attributed to the formation of morphological-dependent resonances
(MDRs) in the aqueous dielectric dimers that lead to the generation of a strong
evanescent MW hotspot between them. Previous experiments have focused on the
electric-field component of the field as the driving force behind the plasma
ignition. Here we couple an ensemble of nitrogen-vacancy (NV) spins in
nanodiamonds (NDs) to the magnetic-field component of the dimer MW field. We
demonstrate the efficient coupling of the NV spins to the MW magnetic-field
hotspot formed between the grape dimers using Optically Detected Magnetic
Resonance (ODMR). The ODMR measurements are performed by coupling NV spins in
NDs to the evanescent MW fields of a copper wire. When placing a pair of grapes
around the NDs and matching the ND position with the expected magnetic-field
hotspot, we see an enhancement in the ODMR contrast by more than a factor of
two compared to the measurements without grapes. Using finite-element
modelling, we attribute our experimental observation of the field enhancement
to the MW hotspot formation between the grape dimers. The present study not
only validates previous work on understanding grape-dimer resonator geometries,
but it also opens up a new avenue for exploring novel MW resonator designs for
quantum technologies.",2311.03951v1
1993-09-29,A Bosonic Mean-Field Theory for Frustrated Heisenberg Antiferromagnets in Two Dimensions,"We use a recently developed bosonic mean-field theory (MFT) to study the
ordered ground states of frustrated Heisenberg antiferromagnets (FHAFM) in two
dimensions. We emphasize the role of condensates in satisfying the MF
variational equations and their relation to spin correlation functions at low
temperatures. Our results are similar to those obtained using Schwinger boson
MFT. However, we emphasize here that our MFT has three bosons at each site and
that it is not necessary to rotate the quantization axes on appropriate
sub-lattices to align all the spins ferromagnetically. This MFT is also closely
related to a new spin-wave theory which enables us to obtain the spin-wave
spectrum easily (without any rotation of axes) for an entire class of
three-dimensionally ordered states. For the FHAFM on a triangular lattice, we
use this theory to compute the spin-wave spectrum for all values of $~J_2 ~/J_1
~$ and demonstrate the phenomenon of order from disorder. (1 figure not
included. Hard copy available on request.)",9309054v1
1997-02-05,Landau Theory of Stripe Phases in Cuprates and Nickelates,"We consider a Landau theory of coupled charge and spin-density wave order
parameters as a simple model for the ordering that has been observed
experimentally in the La_2NiO_4 and La_2CuO_4 families of doped
antiferromagnets. The period of the charge-density wave is generically half
that of the spin-density wave, or equivalently the charges form antiphase
domain walls in the antiferromagnetic order. A sharp distinction exists between
the case in which the ordering is primarily charge driven (which produces a
sequence of transitions in qualitative agreement with experiment) or spin
driven (which does not). We also find that stripes with non-collinear spin
order (i.e. spiral phases) are possible in a region of the phase diagram where
the transition is spin driven; the spiral is circular only when there is no
charge order, and is otherwise elliptical with an eccentricity proportional to
the magnitude of the charge order.",9702055v1
1997-03-25,Phase Diagram of the Half-Filled Extended Hubbard Model in Two Dimensions,"We consider an extended Hubbard model of interacting fermions on a lattice.
The fermion kinetic energy corresponds to a tight binding Hamiltonian with
nearest neighbour (-t) and next nearest neighbour (t') hopping matrix elements.
In addition to the onsite Hubbard interaction (U) we also consider a nearest
neighbour repulsion (V). We obtain the zero temperature phase diagram of our
model within the Hartree-Fock approximation. We consider ground states having
charge and spin density wave ordering as well as states with orbital
antiferromagnetism or spin nematic order. The latter two states correspond to
particle-hole binding with $d_{x^2-y^2}$ symmetry in the charge and spin
channels respectively. For $t' = 0$, only the charge density wave and spin
density wave states are energetically stable. For non-zero t', we find that
orbital antiferromagnetism (or spin nematic) order is stable over a finite
portion of the phase diagram at weak coupling. This region of stability is seen
to grow with increasing values of t'.",9703213v1
1999-02-10,Low Temperature Static and Dynamic Behavior of the Two-Dimensional Easy-Axis Heisenberg Model,"We apply the self-consistent harmonic approximation (SCHA) to study static
and dynamic properties of the two-dimensional classical Heisenberg model with
easy-axis anisotropy. The static properties obtained are magnetization and spin
wave energy as functions of temperature, and the critical temperature as a
function of the easy-axis anisotropy. We also calculate the dynamic correlation
functions using the SCHA renormalized spin wave energy. Our analytical results,
for both static properties and dynamic correlation functions, are compared to
numerical simulation data combining cluster-Monte Carlo algorithms and Spin
Dynamics. The comparison allows us to conclude that far below the transition
temperature, where the SCHA is valid, spin waves are responsible for all
relevant features observed in the numerical simulation data; topological
excitations do not seem to contribute appreciably. For temperatures closer to
the transition temperature, there are differences between the dynamic
correlation functions from SCHA theory and Spin Dynamics; these may be due to
the presence of domain walls and solitons.",9902149v1
1999-02-11,Neutron Scattering Study of Spin Density Wave Order in the Superconducting State of Excess-Oxygen-Doped La2CuO4+y,"We report neutron scattering measurements of spin density wave order within
the superconducting state of a single crystal of predominately stage-4
La2CuO4+y with a Tc(onset) of 42 K. The low temperature elastic magnetic
scattering is incommensurate with the lattice and is characterized by
long-range order in the copper-oxide plane with the spin direction identical to
that in the insulator. Between neighboring planes, the spins exhibit
short-range correlations with a stacking arrangement reminiscent of that in the
undoped antiferromagnetic insulator. The elastic magnetic peak intensity
appears at the same temperature within the errors as the superconductivity,
suggesting that the two phenomena are strongly correlated. These observations
directly reveal the persistent influence of the antiferromagnetic order as the
doping level increases from the insulator to the superconductor. In addition,
our results confirm that spin density wave order for incommensurabilities near
1/8 is a robust feature of the La2CuO4-based superconductors.",9902157v2
2000-01-04,Roton Instability of the Spin Wave Excitation in the Fully Polarized Quatum Hall State and the Phase Diagram at $ν= 2$,"We consider the effect of interactions on electrons confined to two
dimensions at Landau level filling $\nu=2$, with the specific aim to determine
the range of parameters where the fully polarized state is stable. We calculate
the charge and the spin density collective modes in random phase approximation
(RPA) including vertex corrections (also known as time dependent Hartree Fock),
and treating the Landau level mixing accurately within the subspace of a single
particle hole pair. It is found that the spin wave excitation mode of the fully
polarized state has a roton minimum which deepens as a result of the
interaction induced Landau level mixing, and the energy of the roton vanishes
at a critical Zeeman energy signaling an instability of the fully polarized
state at still lower Zeeman energies. The feasibility of the experimental
observation of the roton minimum in the spin wave mode and its softening will
be discussed. The spin and charge density collective modes of the unpolarized
state are also considered, and a phase diagram for the $\nu =2$ state as a
function of $r_{S}$ and the Zeeman energy is obtained.",0001036v1
2005-06-24,Spin dynamics of the quasi two dimensional spin-1/2 quantum magnet Cs_2CuCl_4,"We study dynamical properties of the anisotropic triangular quantum
antiferromagnet Cs_2CuCl_4. Inelastic neutron scattering measurements have
established that the dynamical spin correlations cannot be understood within a
linear spin wave analysis. We go beyond linear spin wave theory by taking
interactions between magnons into account in a 1/S expansion. We determine the
dynamical structure factor and carry out extensive comparisons with
experimental data. We find that compared to linear spin wave theory a
significant fraction of the scattering intensity is shifted to higher energies
and strong scattering continua are present. However, the 1/S expansion fails to
account for the experimentally observed large quantum renormalization of the
exchange energies.",0506667v1
2006-01-02,Three--body Correlation Effects on the Spin Dynamics of Double--Exchange Ferromagnets,"We present a variational calculation of the spin wave excitation spectrum of
double--exchange ferromagnets in different dimensions. Our theory recovers the
Random Phase approximation and 1/S expansion results as limiting cases and can
be used to study the intermediate exchange coupling and electron concentration
regime relevant to the manganites. In particular, we treat exactly the long
range three--body correlations between a Fermi sea electron--hole pair and a
magnon excitation and show that they strongly affect the spin dynamics in the
parameter range relevant to experiments in the manganites. The manifestations
of these correlations are many-fold. We demonstrate that they significantly
change the ferromagnetic phase boundary. In addition to a decrease in the
magnon stiffness, we obtain an instability of the ferromagnetic state against
spin wave excitations close to the Brillouin zone boundary.Within a range of
intermediate concentrations, we find a strong softening of the spin wave
dispersion as compared to the Heisenberg ferromagnet with the same stiffness,
which changes into hardening for other concentrations. We discuss the relevance
of these results to experiments in colossal magnetoresistance ferromagnets.",0601025v2
2006-02-02,Spin waves in the Frustrated Kagome Lattice Antiferromagnet KFe3(OH)6(SO4)2,"The spin wave excitations of the ideal S=5/2 Kagome lattice antiferromagnet
KFe3(OH)6(SO4)2 have been measured using high-resolution inelastic neutron
scattering. We directly observe a flat mode which corresponds to a lifted ""zero
energy mode,"" verifying a fundamental prediction for the Kagome lattice. A
simple Heisenberg spin Hamiltonian provides an excellent fit to our spin wave
data. The antisymmetric Dzyaloshinskii-Moriya interaction is the primary source
of anisotropy and explains the low temperature magnetization and spin
structure.",0602036v2
2007-02-21,"Spin waves throughout the Brillouin zone and magnetic exchange coupling in ferromagnetic metallic manganites La$_{1-x}$Ca$_{x}$MnO$_3$ ($x=0.25,0.30$)","Using time-of-flight and triple-axis inelastic neutron spectroscopy, we
determine spin wave excitations throughout the Brillouin zone for ferromagnetic
manganites La$_{1-x}$Ca$_x$MnO$_3$ ($x=0.25,0.3$) in their low temperature
metallic states. While spin wave excitations in the long wavelength limit (spin
stiffness $D$) have similar values for both compounds, the excitations near the
Brillouin zone boundary of La$_{0.7}$Ca$_{0.3}$MnO$_3$ are considerable
softened in all symmetry directions compared to that of
La$_{0.75}$Ca$_{0.25}$MnO$_3$. A Heisenberg model with the nearest neighbor and
the fourth neighbor exchange interactions can describe the overall dispersion
curves fairly well. We compare the data with various theoretical models
describing the spin excitations of ferromagnetic manganites.",0702504v1
2003-11-04,Avoiding superluminal propagation of higher spin waves via projectors onto W^2 invariant subspaces,"We propose to describe higher spins as invariant subspaces of the Casimir
operators of the Poincar\'{e} Group, P^{2}, and the squared Pauli-Lubanski
operator, W^{2}, in a properly chosen representation, \psi(p) (in momentum
space), of the Homogeneous Lorentz Group. The resulting equation of motion for
any field with s\neq0 is then just a specific combination of the respective
covariant projectors. We couple minimally electromagnetism to this equation and
show that the corresponding wave fronts of the classical solutions propagate
causally. Furthermore, for (s,0)+(0,s) representations, the formalism predicts
the correct gyromagnetic factor, g_{s}=1/s. The advocated method allows to
describe any higher spin without auxiliary conditions and by one covariant
matrix equation alone. This master equation is only quadratic in the momenta
and its dimensionality is that of \psi(p). We prove that the suggested master
equation avoids the Velo-Zwanziger problem of superluminal propagation of
higher spin waves and points toward a consistent description of higher spin
quantum fields.",0311055v2
2001-11-27,"Parity Doubling, Zitterbewegung, and Rest Mass for Spin 1","A 6-component ""wave function"" (not field, but S-matrix interpretable) for a
massive spin-1 particle parallels the Dirac ""chirality-doubled"" 4-component
wave function for a spin-1/2 particle, by pairing two wave functions for same
spin but opposite ""handedness"". The correlated ""opposite-parity"" pair of
complex 3-vectors defines a fluctuating spin-correlated lightlike ``internal
velocity"" as well as an independent ""external rapidity"". Extension from
fermions to vector bosons of the velocity-fluctuation (""zitterbewegung"")
interpretation of rest mass weakens theoretical motivation for elementary
scalar bosons.",0111250v1
2004-02-21,Topological spin transport of photons: the optical Magnus Effect and Berry Phase,"The paper develops a modified geometrical optics (GO) of smoothly
inhomogeneous isotropic medium, which takes into account two topological
phenomena: Berry phase and the optical Magnus effect. By using the analogy
between a quasi-classical motion of a quantum particle with a spin and GO of an
electromagnetic wave in smoothly inhomogeneous media, we have introduced the
standard gauge potential associated with the degeneracy in the wave momentum
space. This potential corresponds to the Dirac-monopole-like field (Berry
curvature), which causes the topological spin (polarization) transport of
photons. The deviations of waves of right-hand and left-hand helicity occur in
the opposite directions and orthogonally to the principal direction of motion.
This produces a spin current directed across the principal motion. The
situation is similar to the anomalous Hall effect for electrons. In addition, a
simple scheme of the experiment allowing one to observe the topological spin
splitting of photons has been suggested.",0402110v1
2010-01-06,Photonic Phase Gate via an Exchange of Fermionic Spin Waves in a Spin Chain,"We propose a new protocol for implementing the two-qubit photonic phase gate.
In our approach, the pi phase is acquired by mapping two single photons into
atomic excitations with fermionic character and exchanging their positions. The
fermionic excitations are realized as spin waves in a spin chain, while photon
storage techniques provide the interface between the photons and the spin
waves. Possible imperfections and experimental systems suitable for
implementing the gate are discussed.",1001.0968v3
2010-06-07,"Theory of spin waves in ferromagnetic (Ga,Mn)As","The collective behavior of spins in a dilute magnetic semiconductor is
determined by their mutual interactions and influenced by the underlying
crystal structure. Hence, we begin with the atomic quantum-mechanical
description of this system using the proposed variational-perturbation
calculus, and then turn to the emerging macroscopic picture employing
phenomenological constants. Within this framework we study spin waves and
exchange stiffness in the p-d Zener model of (Ga,Mn)As, its thin layers and
bulk crystals described by the spds* tight-binding approximation. Analyzing the
anisotropic part of exchange, we find that the Dzyaloshinskii-Moriya
interaction may lead to the cycloidal spin arrangement and uniaxial in-plane
anisotropy in thin layers, resulting in a surface-like anisotropy in thicker
films. We also derive and discuss the spin-wave contribution to magnetization
and Curie temperature. Our theory reconstructs the values of stiffness
determined from the temperature dependence of magnetization, but reproduces
only partly those obtained from analyzing precession modes in (Ga,Mn)As thin
films.",1006.1271v4
2010-10-04,Anisotropic surface transport in topological insulators in proximity to a helical spin density wave,"We study the effects of spatially localized breakdown of time reversal
symmetry on the surface of a topological insulator (TI) due to proximity to a
helical spin density wave (HSDW). The HSDW acts like an externally applied
one-dimensional periodic(magnetic) potential for the spins on the surface of
the TI, rendering the Dirac cone on the TI surface highly anisotropic. The
decrease of group velocity along the direction $\hat{x}$ of the applied spin
potential is twice as much as that perpendicular to $\hat{x}$. At the Brillouin
zone boundaries (BZB) it also gives rise to new semi-Dirac points which have
linear dispersion along $\hat{x}$ but quadratic dispersion perpendicular to
$\hat{x}$. The group velocity of electrons at these new semi-Dirac points is
also shown to be highly anisotropic. Experiments using TI systems on
multiferroic substrates should realize our predictions. We further discuss the
effects of other forms of spin density wave on the surface transport property
of topological insulator.",1010.0683v2
2010-11-03,Temporal behavior of the inverse spin Hall voltage in a magnetic insulator-nonmagnetic metal structure,"It is demonstrated that upon pulsed microwave excitation, the temporal
behavior of a spin-wave induced inverse spin Hall voltage in a magnetic
insulator-nonmagnetic metal structure is distinctly different from the temporal
evolution of the directly excited spin-wave mode from which it originates. The
difference in temporal behavior is attributed to the excitation of long-lived
secondary spin-wave modes localized at the insulator-metal interface.",1011.0889v2
2011-06-27,Effect of intraband Coulomb repulsion on the excitonic spin-density wave,"We present a study of the magnetic ground state of a two-band model with
nested electron and hole Fermi surfaces and both interband and intraband
Coulomb interactions. Our aim is to understand how the excitonic
spin-density-wave (ESDW) state induced by the interband Coulomb repulsion is
affected by the intraband interactions. We first determine the magnetic
instabilities of our model in an unbiased way by employing the random-phase
approximation (RPA) to calculate the static spin susceptibility in the
paramagnetic state. From this, we construct the mean-field phase diagram,
demonstrating the robustness of the ESDW against the intraband interaction. We
then calculate the RPA transverse spin susceptibility in the ESDW state and
show that the intraband Coulomb repulsion significantly renormalizes the
paramagnon line shape and suppresses the spin-wave velocity. We conclude with a
discussion of the relevance of this suppression for the commensurate ESDW state
of Mn-doped Cr alloys.",1106.5315v2
2011-10-03,A novel nonlinear spin wave theory for the spin 1/2 antiferromagnetic Heisenberg model on a triangular lattice,"We extend the nonlinear spin wave theory (NLSWT) for the spin 1/2
antiferromagnetic Heisenberg model on a triangular lattice (TAFHM). This novel
NLSWT considers the corrections one order higher in 1/S than the linear spin
wave theory (LSWT). It also distinguishes in which circumstance the negative
energy excitation, the sign of the breakdown of LSWT, shall be renormalized to
be positive both by a boson normal ordering and a self-consistent iteration. We
draw a phase diagram by testing the stability of various magnetic orders for
different parameters. In particular, the incommensurate configuration is found
unstable by our study. The new phase transition point (PTP) of the collinear
configuration agrees well with various previous studies.",1110.0377v2
2012-06-27,Discrete antiferromagnetic spin-wave excitations in the giant ferric wheel Fe18,"The low-temperature elementary spin excitations in the AFM molecular wheel
Fe18 were studied experimentally by inelastic neutron scattering and
theoretically by modern numerical methods, such as dynamical density matrix
renormalization group or quantum Monte Carlo techniques, and analytical
spin-wave theory calculations. Fe18 involves eighteen spin-5/2 Fe(III) ions
with a Hilbert space dimension of 10^14, constituting a physical system that is
situated in a region between microscopic and macroscopic. The combined
experimental and theoretical approach allowed us to characterize and discuss
the magnetic properties of Fe18 in great detail. It is demonstrated that
physical concepts such as the rotational-band or L&E-band concepts developed
for smaller rings are still applicable. In particular, the higher-lying
low-temperature elementary spin excitations in Fe18 or AFM wheels in general
are of discrete antiferromagnetic spin-wave character.",1206.6203v1
2012-08-17,Routes to heavy-fermion superconductivity,"Superconductivity in lanthanide- and actinide-based heavy-fermion metals can
have different microscopic origins. Among others, Cooper pair formation based
on fluctuations of the valence, of the quadrupole moment or of the spin of the
localized 4f/5f shell have been proposed. Spin-fluctuation mediated
superconductivity in CeCu2Si2 was demonstrated by inelastic neutron scattering
to exist in the vicinity of a spin-density-wave quantum critical point. The
isostructural HF compound YbRh2Si2 which is prototypical for a Kondo-breakdown
quantum critical point has so far not shown any sign of superconductivity down
to approximately 10mK. In contrast, results of de-Haas-van-Alphen experiments
by Shishido et al. (J. Phys. Soc. Jpn. 74, 1103 (2005)) suggest
superconductivity in CeRhIn5 close to an antiferromagnetic quantum critical
point beyond the spin-density-wave type, at which the Kondo effect breaks down.
For the related compound CeCoIn5 however, a field-induced quantum critical
point of spin-density-wave type is extrapolated to exist inside the
superconducting phase.",1208.3684v1
2013-06-08,Systematic Effective Field Theory Analysis of the D=2+1 Quantum XY Model at Low Temperatures,"The low-temperature properties of the (2+1)-dimensional quantum XY model are
studied within the framework of effective Lagrangians up to three-loop order.
At zero temperature, the system is characterized by a spontaneously broken spin
rotation symmetry, O(2) $\to$ 1, where the corresponding Goldstone bosons are
the spin waves or magnons. Even though there is no spontaneously broken order
at finite $T$, the low-temperature behavior of the system is still governed by
the spin waves. The partition function is evaluated and various thermodynamic
quantities, including the order parameter, are derived in the presence of a
weak external field. In particular, we show that the spin-wave interaction is
repulsive at low temperatures, its magnitude depending on the strength of the
external field. We compare our results with those for the (2+1)-dimensional
antiferromagnetic Heisenberg model which, at T=0, exhibits the spontaneously
broken spin rotation symmetry O(3) $\to$ O(2).",1306.1944v1
2013-09-19,Wave packet dynamics in the one-dimensional extended Hubbard model,"Using time-dependent density-matrix renormalization group, we study the time
evolution of electronic wave packets in the one-dimensional extended Hubbard
model with on-site and nearest neighbor repulsion, U and V, respectively. As
expected, the wave packets separate into spin-only and charge-only excitations
(spin-charge separation). Charge and spin velocities exhibit non-monotonic
dependence on V. For small and intermediate values of V, both velocities
increase with V. However, the charge velocity exhibits a stronger dependence
than that of the spin, leading to a more pronounced spin-charge separation.
Charge fractionalization, on the other hand, is weakly affected by V. The
results are explained in terms of Luttinger liquid theory in the weak-coupling
limit, and an effective model in the strong-coupling regime.",1309.5119v1
2014-01-17,Nonreciprocal spin-wave channeling along textures driven by the Dzyaloshinskii-Moriya interaction,"Ultrathin metallic ferromagnets on substrates with strong spin-orbit coupling
can exhibit induced chiral interactions of the Dzyaloshinskii-Moriya (DM) form.
For systems with perpendicular anisotropy, the presence of DM interactions has
important consequences for current-driven domain-wall motion and underpins
possible spintronic applications involving skyrmions. We show theoretically how
spin textures driven by the DM interaction allow nonreciprocal channeling of
spin waves, leading to measurable features in magnetic wires, dots, and domain
walls. Our results provide methods for detecting induced DM interactions in
metallic multilayers and controlling spin wave propagation in ultrathin
nanostructures.",1401.4439v3
2014-07-13,A Renormalization-Group Study of the Symmetry-Breaking Order Parameters in Spin-Orbit Coupled Iridates and Related Systems,"We study the competition between various forms of density-wave-like order
parameters that may arise in multi-orbital correlated materials with strong
spin-orbit coupling (SOC) within a renormalization-group (RG) approach. The
calculations are restricted to models with two spin-orbit split bands having
strong inter-band Fermi surface nesting. We find that for such Fermi surface
topology, the interplay between the inter-band nesting and SOC strongly
enhances the inter-orbital Coulomb interaction (relative to other interactions)
as the system approaches a stable fixed point. This results in an exotic
spin-orbit density wave (SODW) to become the energetically favorable
symmetry-broken state. While the conclusions are generic to such a Fermi
surface topology, the band structure and the numerical results are presented
for the iridate systems. We also find that the electronic fingerprints of the
SODW are in better agreement with various experimental results than a
conventional spin density wave (SDW), explaining the long-standing problem of
the origin of the metal-insulator transition in these systems.",1407.3440v1
2014-09-04,Electron with arbitrary pseudo spins in multilayer graphene,"Using the low-energy effective Hamiltonian of the ABC-stacked multilayer
graphene, pseudo spin coupling to real orbital angular momentum of electron in
multilayer graphene is investigated. We show that electron wave function in
N-layer graphene mimics behavior of particle with spin of N/2. It is said that
for N greater than 1 the low-energy effective Hamiltonian for ABC-stacked
graphene is no longer used to describe pseudo spin 1/2-particle wave function.
The wave function of electron in multilayer graphene may behave like fermionic
(or bosonic) particle when N is odd (or even). This work proposes a theory of
graphene as a host material of electron with arbitrary pseudo spins, tunable by
changing number of graphene layers.",1409.1426v3
2014-12-30,Detecting crystal symmetry fractionalization from the ground state: Application to $\mathbb Z_2$ spin liquids on the kagome lattice,"In quantum spin liquid states, the fractionalized spinon excitations can
carry fractional crystal symmetry quantum numbers, and this symmetry
fractionalization distinguishes different topologically ordered spin liquid
states. In this work we propose a simple way to detect signatures of such
crystal symmetry fractionalizations from the crystal symmetry representations
of the ground state wave function. We demonstrate our method on projected
$\mathbb Z_2$ spin liquid wave functions on the kagome lattice, and show that
it can be used to classify generic wave functions. Particularly our method can
be used to distinguish several proposed candidates of $\mathbb Z_2$ spin liquid
states on the kagome lattice.",1501.00009v2
2015-05-28,Incommensurate spin density wave at a ferromagnetic quantum critical point in a three-dimensional parabolic semimetal,"We explore the ferromagnetic quantum critical point in a three-dimensional
semimetallic system with upward- and downward-dispersing bands touching at the
Fermi level. Evaluating the static spin susceptibility to leading order in the
coupling between the fermions and the fluctuating ferromagnetic order
parameter, we find that the ferromagnetic quantum critical point is masked by
an incommensurate, longitudinal spin density wave phase. We first analyze an
idealized model which, despite having strong spin-orbit coupling, still
possesses O(3) rotational symmetry generated by the total angular momentum
operator. In this case, the direction of the incommensurate spin density wave
propagation can point anywhere, while the magnetic moment is aligned along the
direction of propagation. Including symmetry-allowed anisotropies in the
fermion dispersion and the coupling to the order parameter field, however, the
ordering wavevector instead breaks a discrete symmetry and aligns along either
the [111] or [100] direction, depending on the signs and magnitudes of these
two types of anisotropy.",1505.07685v1
2015-06-17,Partial-wave and helicity operators for the scattering of two hadrons in lattice QCD,"Partial-wave operators for lattice QCD are developed in order to facilitate
the identification of the spins of two-hadron scattering states corresponding
to zero total momentum. Taking the periodic boundary conditions for lattice
states into account, orthogonal sets of partial-wave operators for orbital
angular momentum are identified. When combined with the intrinsic spins of the
hadrons, orthogonal sets of parent operators for total angular momentum $J$ and
projection $M$ are obtained. The parent operators are subduced to irreducible
representations of the octahedral group in order to obtain descendant operators
for use in lattice calculations. The descendant operators retain orthogonality
with respect to $J$. The spin of a state can be identified by the spin of
parent operators that dominate creation of the state. For nonzero total
momentum, operators are developed for a range of helicities and they are
subduced to irreducible representations corresponding to the different
directions of total momentum. Sets of operators that include a sufficient range
of helicities allow identification of spin $J$ when a state couples to
operators with helicities less than or equal to $J$, but not to operators with
higher helicities.",1506.05492v1
2016-05-30,Gauge invariant gluon spin operator for spinless non-linear wave solutions,"We consider non-linear wave type solutions with mass scale parameter and
vahished canonical spin density operator in a pure SU(2) quantum chtomodynamics
(QCD). A new stationary solution which can be treated as a system of static
Wu-Yang monopole dressed in off-diagonal gluon field is proposed. A remarkable
feature of such a solution is that it possesses a finite energy density
everywhere. All considered non-linear wave type solutions have common features:
presence of a mass scale parameter, non-vanishing projection of the color
magnetic field along the propagation direction and zero spin density. The last
property requires revision of the gauge invariant definition of the spin
density operator which supposed to be massless vector field in the classical
theory. We construct a gauge invariant definition of the classical gluon spin
density which is unique and Lorentz frame independent.",1605.09154v4
2016-06-06,Spin-Wave and Electromagnon Dispersions in Multiferroic MnWO4 as Observed by Neutron Spectroscopy: Isotropic Heisenberg Exchange versus Anisotropic Dzyaloshinskii-Moriya Interaction,"High resolution inelastic neutron scattering reveals that the elementary
magnetic excitations in multiferroic MnWO4 consist of low energy dispersive
electromagnons in addition to the well-known spin-wave excitations. The latter
can well be modeled by a Heisenberg Hamiltonian with magnetic exchange coupling
extending to the 12th nearest neighbor. They exhibit a spin-wave gap of 0.61(1)
meV. Two electromagnon branches appear at lower energies of 0.07(1) meV and
0.45(1) meV at the zone center. They reflect the dynamic magnetoelectric
coupling and persist in both, the collinear magnetic and paraelectric AF1
phase, and the spin spiral ferroelectric AF2 phase. These excitations are
associated with the Dzyaloshinskii-Moriya exchange interaction, which is
significant due to the rather large spin-orbit coupling.",1606.01954v1
2016-10-10,"Spin-Wave Spectrum in Magnetic Nanodot with Continuous Transition between Vortex, Bloch-type Skyrmion and Néel-type Skyrmion States","We study spin-wave excitations in a circular ferromagnetic nanodot in
different inhomogeneous, topologically non-trivial magnetization states,
specifically, vortex and skyrmion states. Gradual change in the strength of the
out-of-plane magnetic anisotropy and the Dzyaloshinskii-Moriya exchange
interaction leads to continuous phase transitions between different stable
magnetic configurations and allows for mapping of dynamic spin modes in and
between the vortex, Bloch-type skyrmion and N\'eel-type skyrmion states. Our
study elucidates the connections between gyrotropic modes, azimuthal spin waves
and breathing modes in various stable magnetization states and helps to
understand the rich spin excitation spectrum on the skyrmion background.",1610.02859v1
2017-11-06,Quantum gap and spin-wave excitations in the Kitaev model on a triangular lattice,"We study the effects of quantum fluctuations on the dynamical generation of a
gap and on the evolution of the spin-wave spectra of a frustrated magnet on a
triangular lattice with bond-dependent Ising couplings, analog of the Kitaev
honeycomb model. The quantum fluctuations lift the subextensive degeneracy of
the classical ground-state manifold by a quantum order-by-disorder mechanism.
Nearest-neighbor chains remain decoupled and the surviving discrete degeneracy
of the ground state is protected by a hidden model symmetry. We show how the
four-spin interaction, emergent from the fluctuations, generates a spin gap
shifting the nodal lines of the linear spin-wave spectrum to finite energies.",1711.02016v1
2017-11-22,Irreversible Markov chains in spin models: Topological excitations,"We analyze the convergence of the irreversible event-chain Monte Carlo
algorithm for continuous spin models in the presence of topological
excitations. In the two-dimensional XY model, we show that the local nature of
the Markov-chain dynamics leads to slow decay of vortex-antivortex correlations
while spin waves decorrelate very quickly. Using a Frechet description of the
maximum vortex-antivortex distance, we quantify the contributions of
topological excitations to the equilibrium correlations, and show that they
vary from a dynamical critical exponent z \sim 2 at the critical temperature to
z \sim 0 in the limit of zero temperature. We confirm the event-chain
algorithm's fast relaxation (corresponding to z = 0) of spin waves in the
harmonic approximation to the XY model. Mixing times (describing the approach
towards equilibrium from the least favorable initial state) however remain much
larger than equilibrium correlation times at low temperatures. We also describe
the respective influence of topological monopole-antimonopole excitations and
of spin waves on the event-chain dynamics in the three-dimensional Heisenberg
model.",1711.08375v1
2018-10-23,Magnonic Analogue of Black/White Hole Horizon in Superfluid $^3$He-B,"We report on theoretical model and experimental results of the experiment
made in a limit of absolute zero temperature ($\sim$ 600\,$\mu$K) studying the
spin wave analogue of black/white hole horizon using spin (magnonic)
superfluidity in superfluid $^3$He-B. As an experimental tool simulating the
properties of the black/white horizon we used the spin-precession waves
propagating on the background of the spin super-currents between two
Bose-Einstein condensates of magnons in form of homogeneously precessing
domains. We provide experimental evidence of the white hole formation for spin
precession waves in this system, together with observation of an amplification
effect. Moreover, the estimated temperature of the spontaneous Hawking
radiation in this system is about four orders of magnitude lower than the
system's background temperature what makes it a promising tool to study the
effect of spontaneous Hawking radiation.",1810.09890v2
2016-12-26,Magnetic excitations in a three-orbital model for the strongly spin-orbit coupled iridates: Effect of mixing between the J=1/2 and 3/2 sectors,"A three-orbital-model approach for studying spin wave excitations in the
strongly spin-orbit coupled layered perovskite iridates is presented which
provides a unified description of magnetic excitations as well as the
electronic band structure. The calculated spin wave dispersions with realistic
three-band parameters are in excellent agreement with the RIXS data for
iridates, including the strong AF zone boundary dispersion in the single-layer
compound $\rm Sr_2 Ir O_4$ and the large anisotropy gap in the bilayer compound
$\rm Sr_3 Ir_2 O_7$. The RIXS spin wave data is shown to provide evidence of
mixing between the J=1/2 and 3/2 sectors in both compounds.",1612.08360v1
2017-06-20,"Optical Momentum, Spin, and Angular Momentum in Dispersive Media","We examine the momentum, spin, and orbital angular momentum of structured
monochromatic optical fields in dispersive inhomogeneous isotropic media. There
are two bifurcations in this general problem: the Abraham-Minkowski dilemma and
the kinetic (Poynting-like) versus canonical (spin-orbital) pictures. We show
that the kinetic Abraham momentum describes the energy flux and group velocity
of the wave in the medium. At the same time, we introduce novel canonical
Minkowsky-type momentum, spin, and orbital angular momentum densities of the
field. These quantities exhibit fairly natural forms, analogous to the
Brillouin energy density, as well as multiple advantages as compared with
previously considered formalisms. We apply this general theory to inhomogeneous
surface plasmon-polariton (SPP) waves at a metal-vacuum interface and show that
SPPs carry a ""super-momentum"", proportional to the wave vector $k_{p} >
\omega/c$, and a transverse spin, which can change its sign depending on the
frequency $\omega$.",1706.06406v2
2021-02-24,Quantum hydrodynamics of the spinor Bose-Einstein condensate at non-zero temperatures,"Finite temperature hydrodynamic model is derived for the spin-1 ultracold
bosons by the many-particle quantum hydrodynamic method. It is presented as the
two fluid model of the BEC and normal fluid. The linear and quadratic Zeeman
effects are included. Scalar and spin-spin like short-range interactions are
considered in the first order by the interaction radius. It is also represented
as the set of two nonlinear Pauli equations. The spectrum of the bulk
collective excitations is considered for the ferromagnetic phase in the small
temperature limit. The spin wave is not affected by the presence of the small
temperature in the described minimal coupling model, where the thermal part of
the spin-current of the normal fluid is neglected. The two sound waves are
affected by the spin evolution in the same way as the change of spectrum of the
single sound wave in BEC, where speed of sound is proportional to $g_{1}+g_{2}$
with $g_{i}$ are the interaction constants.",2102.12538v1
2019-01-24,Spin and orbital angular momenta of acoustic beams,"We analyze spin and orbital angular momenta in monochromatic acoustic wave
fields in a homogeneous medium. Despite being purely longitudinal (curl-free),
inhomogeneous acoustic waves generically possess nonzero spin angular momentum
density caused by the local rotation of the vector velocity field. We show that
the integral spin of a localized acoustic wave vanishes in agreement with the
spin-0 nature of longitudinal phonons. We also show that the helicity or
chirality density vanishes identically in acoustic fields. As an example, we
consider nonparaxial acoustic Bessel beams carrying well-defined integer
orbital angular momentum, as well as nonzero local spin density, with both
transverse and longitudinal components. We describe the nontrivial polarization
structure in acoustic Bessel beams and indicate a number of observable
phenomena, such as nonzero energy density and purely-circular transverse
polarization in the center of the first-order vortex beams.",1901.08962v3
2019-07-10,How to search for gravitational waves from $r$-modes of known pulsars,"Searches for continuous gravitational waves from known pulsars so far have
been targeted at or near the spin frequency or double the spin frequency of
each pulsar, appropriate for mass quadrupole emission. But some neutron stars
might radiate strongly through current quadrupoles via $r$-modes, which
oscillate at about four thirds the spin frequency. We show for the first time
how to construct searches over appropriate ranges of frequencies and spin-down
parameters to target $r$-modes from known pulsars. We estimate computational
costs and sensitivities of realistic $r$-mode searches using the coherent
$\mathcal{F}$-statistic, and find that feasible searches for known pulsars can
beat spin-down limits on gravitational wave emission even with existing LIGO
and Virgo data.",1907.04946v1
2019-07-16,Singular spin-flip interactions for the 1D Schrödinger operator,"We consider singular self-adjoint extensions for one-dimensional
Schr\""{o}dinger operator for two-component wave function within the framework
of the distribution theory for discontinuous test functions
\cite{funcan_deltadistr_kurasov_jmathan1996}. We show that among
$\mathds{C}^{4}$-parameter set of boundary conditions with state mixing there
is only $\mathds{R}^2$-parameter subset compatible with the spin interpretation
of the two-component structure of the wave function. For the spin
interpretation of such wave function they can be identified as the point-like
spin-momentum (Rashba) interactions. We suggest their physical realizations
based on the regularized form of the Hamiltonian which couples the electrical
field inhomogeneity to spin.",1907.06893v4
2019-10-08,Spatial coherence of spin-orbit-coupled Bose gases,"Spin-orbit-coupled Bose-Einstein condensates (SOBECs) exhibit two new phases
of matter, now known as the stripe and plane-wave phases. When two interacting
spin components of a SOBEC spatially overlap, density modulations with
periodicity given by the spin-orbit coupling strength appear. In equilibrium,
these components fully overlap in the miscible stripe phase, and overlap only
in a domain wall in the immiscible plane-wave phase. Here we probe the density
modulation present in any overlapping region with optical Bragg scattering, and
observe the sudden drop of Bragg scattering as the overlapping region shrinks.
Using an atomic analogue of the Talbot effect, we demonstrate the existence of
long-range coherence between the different spin components in the stripe phase
and surprisingly even in the phase-separated plane-wave phase.",1910.03613v1
2021-01-12,Temperature dependent appearance of exotic matter makes nascent neutron stars spin faster,"Neutron stars offer the opportunity to study the behaviour of matter at
densities and temperatures inaccessible to terrestrial experiments.
Gravitational-wave observations of binary neutron star coalescences can
constrain the neutron-star equation of state before and after merger. After the
neutron star binary merges, hyperons can form in the remnant, changing the
behaviour of the neutron-star equation of state. In this study, we use
finite-entropy equations of state to show that a post-merger remnant can spin
up due to cooling. The magnitude of the spin-up depends on the neutron-star
equation of state. If hyperons are present, the post-merger spin-up changes the
peak gravitational-wave frequency by $\sim 540$ Hz, when the entropy per baryon
drops from $s=2$ $k_B$ to $s=0$ $k_B$. If hyperons are not present, the
post-merger spin-up changes by $\sim 360$ Hz, providing a gravitational-wave
signature for exotic matter. We expect the same qualitative behaviour whenever
temperature dependent phase transitions are triggered.",2101.04782v1
2021-12-08,Topological Doping and Superconductivity in Cuprates: An Experimental Perspective,"Hole doping into a correlated antiferromagnet leads to topological stripe
correlations, involving charge stripes that separate antiferromagnetic spin
stripes of opposite phase. Topological spin stripe order causes the spin
degrees of freedom within the charge stripes to feel a geometric frustration
with their environment. In the case of cuprates, where the charge stripes have
the character of a hole-doped two-leg spin ladder, with corresponding pairing
correlations. Anti-phase Josephson coupling across the spin stripes can lead to
pair-density-wave order, in which broken translation symmetry of the
superconducting wave function is accommodated by pairs with finite momentum.
This scenario has now been experimentally verified by recently reported
measurements on La$_{2-x}$Ba$_x$CuO$_4$ with $x=1/8$. While pair-density-wave
order is not common as a cuprate ground state, it provides a basis for
understanding the uniform $d$-wave order that is more typical in
superconducting cuprates.",2112.04557v1
2022-01-13,Gravitational radiation from inspiralling compact objects: Spin effects to fourth Post-Newtonian order,"The linear- and quadratic-in-spin contributions to the binding potential and
gravitational-wave flux from binary systems are derived to
next-to-next-to-leading order in the Post-Newtonian (PN) expansion of general
relativity, including finite-size and tail effects. The calculation is carried
out through the worldline effective field theory framework. We find agreement
in the overlap with the available PN literature and test-body limit. As a
direct application, we complete the knowledge of spin effects in the evolution
of the orbital phase for aligned-spin circular orbits to fourth PN order. We
estimate the impact of the new results in the number of accumulated
gravitational-wave cycles. We find they will play an important role in
providing reliable physical interpretation of gravitational-wave signals from
spinning binaries with future detectors such as LISA and the Einstein
Telescope.",2201.05138v1
2023-03-22,Classification and emergence of quantum spin liquids in chiral Rydberg models,"We investigate the nature of quantum phases arising in chiral interacting
Hamiltonians recently realized in Rydberg atom arrays. We classify all possible
fermionic chiral spin liquids with $\mathrm{U}(1)$ global symmetry using parton
construction on the honeycomb lattice. The resulting classification includes
six distinct classes of gapped quantum spin liquids: the corresponding
variational wave functions obtained from two of these classes accurately
describe the Rydberg many-body ground state at $1/2$ and $1/4$ particle
density. Complementing this analysis with tensor network simulations, we
conclude that both particle filling sectors host a spin liquid with the same
topological order of a $\nu=1/2$ fractional quantum Hall effect. At density
$1/2$, our results clarify the phase diagram of the model, while at density
$1/4$, they provide an explicit construction of the ground state wave function
with almost unit overlap with the microscopic one. These findings pave the way
to the use of parton wave functions to guide the discovery of quantum spin
liquids in chiral Rydberg models.",2303.12829v2
2023-04-27,Coherent magnetization dynamics in strongly quenched Ni thin films,"The remagnetization process after ultrafast demagnetization can be described
by relaxation mechanisms between the spin, electron, and lattice reservoirs.
Thereby, collective spin excitations in form of spin waves and their angular
momentum transfer play an important role on the longer timescales. In this
work, we address the question whether the strength of demagnetization affects
the coherency and the phase of the excited spin waves. We present a study of
coherent magnetization dynamics in thin nickel films after ultrafast
demagnetization using the all-optical, time-resolved magneto-optical
Kerr-effect (tr-MOKE) technique. The largest coherent oscillation amplitude was
observed for strongly quenched systems, showing the conservation of coherency
for demagnetizations of up to 90%. Moreover, the phase of the excited
spin-waves increases with pump power, indicating a delayed start of the
precession during the remagnetization.",2304.14325v1
2023-10-09,Ordered phases and superconductivity in two-dimensional electron systems subject to pair spin-orbit interaction,"Pair spin-orbit interaction can emerge in strongly-interacting systems
characterized by a large spin-orbit coupling. Here we study the role of this
interaction in stabilizing ordered and unconventional superconducting phases.
We find that, if the system avoids superconductivity, the order realized is a
combination of charge-density and spin-vorticity waves. The latter is
reminiscent of a loop-current state, albeit in the spin, rather in the charge,
channel. If the system becomes superconducting, the order parameter assumes the
form of a paired density wave, i.e. pairing occurs at finite momentum.
Intriguingly, one of the possible pairings acquires a form analogous to
Amperean superconductivity. However, the order parameter here is always a blend
of paired density wave and Amperean pairing, rather than being purely one or
the other.",2310.06190v1
2023-11-17,Superradiance in the Kerr-Taub-NUT spacetime,"Superradiance is the effect of field waves being amplified during reflection
from a charged or rotating black hole. In this paper, we study the low-energy
dynamics of super-radiant scattering of massive scalar and massless higher spin
field perturbations in a generic axisymmetric stationary Kerr-Taub-NUT
(Newman-Unti-Tamburino) spacetime, which represents sources with both
gravitomagnetic monopole moment (magnetic mass) and gravitomagnetic dipole
moment (angular momentum). We obtain a generalized Teukolsky master equation
for all spin perturbation fields. The equations are separated into their
angular and radial parts. The angular equations lead to spin-weighted
spheroidal harmonic functions that generalize those in Kerr spacetime. We
identify an effective spin as a coupling between frequency (or energy) and the
NUT parameter. The behaviors of the radial wave function near the horizon and
at the infinite boundary are studied. We provide analytical expressions for
low-energy observables such as emission rates and cross sections of all
massless fields with spin, including scalar, neutrino, electromagnetic,
Rarita-Schwinger, and gravitational waves.",2311.10559v1
2023-11-25,Spin pumping in YIG-Pt structures: the role of the van Hove singularities,"Spin pumping by surface and backward volume magnetostatic waves in YIG/Pt
structures is experimentally studied and analyzed. It is shown that at
frequencies corresponding to van Hove singularities in the density of states of
the spin wave spectrum, an increase in the efficiency of electron-magnon
scattering and spin current generation takes place. The obtained results are
important for spin wave-based spintronic devices development.",2311.15096v1
2023-11-27,Evidence of spin density waves in La$_3$Ni$_2$O$_{7-δ}$,"The recently discovered superconductivity with critical temperature $T_{c}$
up to 80 K in the Ruddlesden-Popper phases La$_3$Ni$_2$O$_{7-\delta}$ under
pressure has drawn great attention. Here we report the positive muon spin
relaxation ($\mu^+$SR) study of polycrystalline La$_3$Ni$_2$O$_{7-\delta}$
under ambient pressure. The zero-field $\mu^+$SR experiments reveal the
existence of static long range magnetic order in La$_3$Ni$_2$O$_{7-\delta}$,
and the the muon spin depolarization spectra are consistent with the spin
density wave internal field distribution. The weak transverse field $\mu^+$SR
measurements suggest the bulk magnetic transition near $T_{\rm{N}}=148$ K. This
is the first research which discovers the existence of the spin density wave in
La$_3$Ni$_2$O$_{7-\delta}$ microscopically.",2311.15717v1
2024-01-28,Magnetic interactions and excitations in SrMnSb$_2$,"The magnetic interactions in the antiferromagnetic (AFM) Dirac semimetal
candidate SrMnSb$_2$ are investigated using \textit{ab initio} linear response
theory and inelastic neutron scattering (INS). Our calculations reveal that the
first two nearest in-plane couplings ($J_1$ and $J_2$) are both AFM in nature,
indicating a significant degree of spin frustration, which aligns with
experimental observations. The orbital resolution of exchange interactions
shows that $J_1$ and $J_2$ are dominated by direct and superexchange,
respectively. In a broader context, a rigid-band model suggests that electron
doping fills the minority spin channel and results in a decrease in the AFM
coupling strength for both $J_1$ and $J_2$. To better compare with INS
experiments, we calculate the spin wave spectra within a linear spin wave
theory framework, utilizing the computed exchange parameters. The calculated
spin wave spectra exhibit overall good agreement with measurements from INS
experiments, although with a larger magnon bandwidth. Introducing additional
electron correlation within the Mn-$3d$ orbitals can promote electron
localization and reduce the magnetic coupling, further improving the agreement
with experiments.",2401.15572v1
2024-02-02,THz spin-wave excitations in the transverse conical phase of BiFeO$_3$,"Although BiFeO$_3$ is one of the most studied multiferroic materials, recent
magnetization and neutron scattering studies have revealed a new magnetic phase
in this compound - the transverse conical phase. To study the collective spin
excitations of this phase, we performed THz spectroscopy in magnetic fields up
to 17 T at and above room temperature. We observed five spin-wave branches in
the magnetic phase with long wavelength conical modulation. Using a numerical
spin dynamics model we found two kinds of excitations with magnetic moments
oscillating either along or perpendicular to the static fields. Remarkably, we
detected strong directional dichroism, an optical manifestation of the
magnetoelectric effect, for two spin-wave modes of the conical phase. According
to our experiments, the stability of the conical state is sensitive to the
magnetic field history and it can become (meta)stable at or close to zero
magnetic field, which may allow exploiting its magnetoelectric properties at
room temperature.",2402.01417v1
2008-02-07,Spin-wave interaction in two-dimensional ferromagnets with dipolar forces,"We discuss the spin-wave interaction in two-dimensional (2D) Heisenberg
ferromagnet (FM) with dipolar forces at $T_C\gg T\ge0$ using 1/S expansion. A
comprehensive analysis is carried out of the first 1/S corrections to the
spin-wave spectrum. In particular, similar to 3D FM discussed in our previous
paper A.V. Syromyatnikov, PRB {\bf 74}, 014435 (2006), we obtain that the
spin-wave interaction leads to the {\it gap} in the spectrum $\epsilon_{\bf k}$
renormalizing greatly the bare gapless spectrum at small momenta $k$.
Expressions for the spin-wave damping $\Gamma_{\bf k}$ are derived
self-consistently and it is concluded that magnons are well-defined
quasi-particles in both quantum and classical 2D FMs at small $T$. We observe
thermal enhancement of both $\Gamma_{\bf k}$ and $\Gamma_{\bf k}/\epsilon_{\bf
k}$ at small momenta. In particular, a peak appears in $\Gamma_{\bf k}$ and
$\Gamma_{\bf k}/\epsilon_{\bf k}$ at small $k$ and at any given direction of
$\bf k$. If $S\sim1$ the height of the peak in $\Gamma_{\bf k}/\epsilon_{\bf
k}$ is not larger than a value proportional to $T/D\ll1$, where $D$ is the
spin-wave stiffness. In the case of large spins $S\gg1$ the peak in
$\Gamma_{\bf k}/\epsilon_{\bf k}$ cannot be greater than that of the classical
2D FM found at $k=0$ which height is small only {\it numerically}: $\Gamma_{\bf
0}/\epsilon_{\bf 0}\approx0.16$ for the simple square lattice. Frustrating
next-nearest-neighbor exchange coupling increases $\Gamma_{\bf 0}/\epsilon_{\bf
0}$ in classical 2D FM only slightly. We find expressions for spin Green's
functions and the magnetization. The latter differs from the well-known result
by S.V. Maleev, Sov. Phys. JETP {\bf 43}, 1240 (1976). The effect of the
exchange anisotropy is also discussed briefly.",0802.0958v1
1998-05-05,Thermally Activated Resonant Magnetization Tunneling in Molecular Magnets: Mn_12Ac and others,"The dynamical theory of thermally activated resonant magnetization tunneling
in uniaxially anisotropic magnetic molecules such as Mn_12Ac (S=10) is
developed.The observed slow dynamics of the system is described by master
equations for the populations of spin levels.The latter are obtained by the
adiabatic elimination of fast degrees of freedom from the density matrix
equation with the help of the perturbation theory developed earlier for the
tunneling level splitting [D. A. Garanin, J. Phys. A, 24, L61 (1991)]. There
exists a temperature range (thermally activated tunneling) where the escape
rate follows the Arrhenius law, but has a nonmonotonic dependence on the bias
field due to tunneling at the top of the barrier. At lower temperatures this
regime crosses over to the non-Arrhenius law (thermally assisted tunneling).
The transition between the two regimes can be first or second order, depending
on the transverse field, which can be tested in experiments. In both regimes
the resonant maxima of the rate occur when spin levels in the two potential
wells match at certain field values. In the thermally activated regime at low
dissipation each resonance has a multitower self-similar structure with
progressively narrowing peaks mounting on top of each other.",9805057v1
1998-12-17,Resonant Processes in a Frozen Gas,"We present a theory of resonant processes in a frozen gas of atoms
interacting via dipole-dipole potentials that vary as $r^{-3}$, where $r$ is
the interatomic separation. We supply an exact result for a single atom in a
given state interacting resonantly with a random gas of atoms in a different
state. The time development of the transition process is calculated both on-
and off-resonance, and the linewidth with respect to detuning is obtained as a
function of time $t$. We introduce a random spin Hamiltonian to model a dense
system of resonators and show how it reduces to the previous model in the limit
of a sparse system. We derive approximate equations for the average effective
spin, and we use them to model the behavior seen in the experiments of Anderson
et al. and Lowell et al. The approach to equilibrium is found to be
proportional to $\exp (-\sqrt{\gamma_{eq}t}$), where the constant $\gamma
_{eq}$ is explicitly related to the system's parameters.",9812313v2
1999-10-20,Magnetic resonance in the antiferromagnetic and normal state of NH_3K_3C_60,"We report on the magnetic resonance of NH_3K_3C_60 powders in the frequency
range of 9 to 225 GHz. The observation of an antiferromagnetic resonance below
the phase transition at 40 K is evidence for an antiferromagnetically ordered
ground state. In the normal state, above 40 K, the temperature dependence of
the spin-susceptibilty measured by ESR agrees with previous static measurements
and is too weak to be explained by interacting localized spins in an insulator.
The magnetic resonance line width has an unusual magnetic-field dependence
which is large and temperature independent in the magnetically ordered state
and decreases rapidly above the transition. These observations agree with the
suggestion that NH_3K_3C_60 is a metal in the normal state and undergoes a
Mott-Hubbard metal to insulator transition at 40 K.",9910303v1
2001-02-05,Spin Effects and Transport in Quantum Dots with overlapping Resonances,"The role of spin is investigated in the transport through a quantum dot with
two overlapping resonances (one having a width larger than the level separation
and the other very narrow, cf. Silvestrov and Imry, Phys. Rev. Lett. {\bf 85},
2565 (2000)). For a series of consecutive charging resonances, one electron
from the leads populates one and the same broad level in the dot. Moreover,
there is the tendency to occupy the same level also by the second electron
within the same resonance. This second electron is taken from the narrow levels
in the dot. The narrow levels are populated (and broad level is depopulated)
via sharp rearrangements of the electronic configuration in the Coulomb
blockade valleys. Possible experimental manifestations of this scenario are
considered. Among these there are sharp features in the valleys and in the
Mixed Valence regime and an unusual Kondo effect.",0102088v3
2001-03-22,Doping dependence of the resonance peak and incommensuration in high-$T_{c}$ superconductors,"The doping and frequency evolutions of the incommensurate spin response and
the resonance mode are studied based on the scenario of the Fermi surface
topology. We use the slave-boson mean-field approach to the $t-t^{\prime}-J$
model and including the antiferromagnetic fluctuation correction in the
random-phase approximation. We find that the equality between the
incommensurability and the hole concentration is reproduced at low frequencies
in the underdoped regime. This equality observed in experiments was explained
{\it only} based on the stripe model before. We also obtain the downward
dispersion for the spin response and predict its doping dependence for further
experimental testing, as well as a proportionality between the low-energy
incommensurability and the resonance energy. Our results suggest a common
origin for the incommensuration and the resonance peak based on the Fermi
surface topology and the d-wave symmetry.",0103456v1
2005-07-27,p-Wave Interactions in Low-Dimensional Fermionic gases,"We study a spin-polarized degenerate Fermi gas interacting via a p-wave
Feshbach resonance in an optical lattice. The strong confinement available in
this system allows us to realize one- and two-dimensional gases and therefore
to restrict the asymptotic scattering states of atomic collisions. When
aligning the atomic spins along (or perpendicular to) the axis of motion in a
one-dimensional gas, scattering into channels with the projection of the
angular momentum of |m|=1 (or m=0) can be inhibited. In two and three
dimensions we observe the doublet structure of the p-wave Feshbach resonance.
Both for the one-dimensional and the two-dimensional gas we find a shift of the
position of the resonance with increasing confinement due to the change in
collisional energy. In a three-dimensional optical lattice the losses on the
Feshbach resonance are completely suppressed.",0507632v2
2006-07-05,Theory of the spin-torque-driven ferromagnetic resonance in a ferromagnet/normal-metal/ferromagnet structure,"We present a theoretical analysis of current driven ferromagnetic resonance
in a ferromagnet/normal-metal/ferromagnet tri-layer. This method of driving
ferromagnetic resonance was recently realized experimentally by Tulapurkar et
al. [Nature 438, 339 (2005)] and Sankey et al. [Phys. Rev. Lett. 96, 227601
(2006)]. The precessing magnetization rectifies the alternating current applied
to drive the ferromagnetic resonance and leads to the generation of a dc
voltage. Our analysis shows that a second mechanism to generate a dc voltage,
rectification of spin currents emitted by the precessing magnetization, has a
contribution to the dc voltage that is of approximately equal size for the thin
ferromagnetic films used in the experiment.",0607145v2
2006-08-07,Transport spectroscopy of a single dopant in a gated silicon nanowire,"We report on spectroscopy of a single dopant atom in silicon by resonant
tunneling between source and drain of a gated nanowire etched from silicon on
insulator. The electronic states of this dopant isolated in the channel appear
as resonances in the low temperature conductance at energies below the
conduction band edge. We observe the two possible charge states successively
occupied by spin-up and spin-down electrons under magnetic field. The first
resonance is consistent with the binding energy of the neutral $D^0$ state of
an arsenic donor. The second resonance shows a reduced charging energy due to
the electrostatic coupling of the charged $D^-$ state with electrodes. Excited
states and Zeeman splitting under magnetic field present large energies
potentially useful to build atomic scale devices.",0608159v2
2007-03-27,Resonance in Optimally Electron-Doped Superconductor Nd$_{1.85}$Ce$_{0.15}$CuO$_{4-δ}$,"We use inelastic neutron scattering to probe magnetic excitations of an
optimally electron-doped superconductor Nd$_{1.85}$Ce$_{0.15}$CuO$_{4-\delta}$
above and below its superconducting transition temperature $T_c=25$ K. In
addition to gradually opening a spin pseudo gap at the antiferromagnetic
ordering wavevector ${\bf Q}=(1/2,1/2,0)$, the effect of superconductivity is
to form a resonance centered also at ${\bf Q}=(1/2,1/2,0)$ but at energies
above the spin pseudo gap. The intensity of the resonance develops like a
superconducting order parameter, similar to those for hole-doped
superconductors and electron-doped Pr$_{0.88}$LaCe$_{0.12}$CuO$_4$. The
resonance is therefore a general phenomenon of cuprate superconductors, and
must be fundamental to the mechanism of high-$T_c$ superconductivity.",0703732v2
2006-10-30,Barionic Resonances with Positive Strangeness S=+1 in the System nK+ from the Reaction np -> npK+K- at the Momentum of Incident Neutrons Pn=5.20 Gev/c,"The production and properties of the resonances with the strangeness S=+1 in
the system of nK+ were studied in the reaction np->npK+K- at the momentum of
incident neutrons Pn=(5.20 +/- 0.12)GeV/c. A number of peculiarities were found
in the effective mass spectrum of the mentioned above system. Their widths are
comparable with the mass resolution. The estimation of the spins of resonances
was carried out and the rotational band connecting the resonances masses and
their spins was constructed.",0610085v3
2006-07-25,Quark-Hadron Duality in Spin Structure Functions g1p and g1d,"New measurements of the spin structure functions of the proton and deuteron
g1p(x,Q2) and g1d(x,Q2) in the nucleon resonance region are compared with
extrapolations of target-mass-corrected next-to-leading-order (NLO) QCD fits to
higher energy data. Averaged over the entire resonance region (W<2 GeV), the
data and QCD fits are in good agreement in both magnitude and Q2 dependence for
Q2>1.7 GeV2. This global duality appears to result from cancellations among the
prominent local resonance regions: in particular strong sigma{3/2}
contributions in the Delta(1232) region appear to be compensated by strong
sigma{1/2} contributions in the resonance region centered on 1.5 GeV. These
results are encouraging for the extension of NLO QCD fits to lower W and Q2
than have been used previously.",0607283v1
2006-08-04,On different lagrangian formalisms for vector resonances within chiral perturbation theory,"We study the relation of vector Proca field formalism and antisymmetric
tensor field formalism for spin-one resonances in the context of the large N_C
inspired chiral resonance Lagrangian systematically up to the order O(p6) and
give a transparent prescription for the transition from vector to antisymmetric
tensor Lagrangian and vice versa. We also discuss the possibility to describe
the spin-one resonances using an alternative ""mixed"" first order formalism,
which includes both types of fields simultaneously, and compare this one with
the former two. We also briefly comment on the compatibility of the above
lagrangian formalisms with the high-energy constraints for concrete VVP
correlator.",0608051v1
1998-04-30,Structure and decay properties of spin-dipole giant resonances within a semimicroscopical approach,"A semimicroscopical approach is applied to calculate: (i) strength functions
for the charge-exchange spin-dipole giant resonances in the 208Pb parent
nucleus; (ii) partial and total branching ratios for the direct proton decay of
the resonance in 208Bi. The approach is based on continuum-RPA calculations of
corresponding reaction-amplitudes and phenomenological description of the
doorway-state coupling to many-quasiparticle configurations. The only
adjustable parameter needed for the description is found by comparison of the
calculated and experimental total widths of the resonance. Other model
parameters used in calculations are taken from independent data. The calculated
total branching ratio is found to be in reasonable agreement with the
experimental value.",9804076v1
2004-05-09,N and Delta Resonances in the Rigid Quark-Diquark Vibrator,"A nearest-neighbor analysis of light flavor baryon mass spectra reveals
striking degeneracy patterns- narrow mass bands populated by series of parity
twins of steadily increasing spins. Each series terminates by an unpaired
resonance of the highest spin in the group. We trace back such degenerate
series of resonances (to be termed ""mega states"") to internal baryon structure
dominated by a quark -(rigid di-quark) configuration. Nucleon and Delta spectra
are, surprisingly enough, exact replicas to each other in the sense that each
of them features three mega states of equal quantum numbers. We fit positions
and splittings of the observed mega states by an algebraic Hamiltonian which
translates into a potential that is a combination of Coulomb- and Morse like
potentials and predict few more such degenerate series to be observed by the
TJNAF missing resonance program. Finally, we explore consequences of the model
for some electrodynamic properties of the spectra.",0405023v1
2008-05-26,Magnetic field induced incommensurate resonance in cuprate superconductors,"The influence of a uniform external magnetic field on the dynamical spin
response of cuprate superconductors in the superconducting state is studied
based on the kinetic energy driven superconducting mechanism. It is shown that
the magnetic scattering around low and intermediate energies is dramatically
changed with a modest external magnetic field. With increasing the external
magnetic field, although the incommensurate magnetic scattering from both low
and high energies is rather robust, the commensurate magnetic resonance
scattering peak is broadened. The part of the spin excitation dispersion seems
to be an hourglass-like dispersion, which breaks down at the heavily low energy
regime. The theory also predicts that the commensurate resonance scattering at
zero external magnetic field is induced into the incommensurate resonance
scattering by applying an external magnetic field large enough.",0805.3922v2
2008-11-13,Template nanowires for spintronics applications: nanomagnet microwave resonators functioning in zero applied magnetic field,"Low-cost spintronic devices functioning in zero applied magnetic field are
required for bringing the idea of spin-based electronics into the real-world
industrial applications. Here we present first microwave measurements performed
on nanomagnet devices fabricated by electrodeposition inside porous membranes.
In the paper, we discuss in details a microwave resonator consisting of three
nanomagnets, which functions in zero external magnetic field. By applying a
microwave signal at a particular frequency, the magnetization of the middle
nanomagnet experiences the ferromagnetic resonance (FMR), and the device
outputs a measurable direct current (spin-torque diode effect). Alternatively,
the nanodevice can be used as a microwave oscillator functioning in zero field.
In order to test the resonators at microwave frequencies, we developed a simple
measurement set-up.",0811.2241v1
2009-06-02,Measurement of electron correlations in LixCoO2 (x=0.0 - 0.35) using 59Co nuclear magnetic resonance and nuclear quadrupole resonance techniques,"CoO2 is the parent compound for the superconductor NaxCoO2\cdot1.3H2O and was
widely believed to be a Mott insulator. We performed 59Co nuclear magnetic
resonance (NMR) and nuclear quadrupole resonance (NQR) studies on LixCoO2 (x =
0.35, 0.25, 0.12, and 0.0) to uncover the electronic state and spin
correlations in this series of compounds which was recently obtained through
electrochemical de-intercalation of Li from pristine LiCoO2. We find that
although the antiferromagnetic spin correlations systematically increase with
decreasing Li-content (x), the end member, CoO2 is a non-correlated metal that
well satisfies the Korringa relation for a Fermi liquid. Thus, CoO2 is not
simply located at the limit of x->0 for AxCoO2 (A = Li, Na) compounds. The
disappearance of the electron correlations in CoO2 is due to the three
dimensionality of the compound which is in contrast to the highly two
dimensional structure of AxCoO2.",0906.0400v1
2010-02-17,Dispersion of the superconducting spin resonance in underdoped and antiferromagnetic Ba(Fe1-xCox)2As2,"Inelastic neutron scattering measurements have been performed on underdoped
Ba(Fe1-xCox)2As2 (x = 4.7%) where superconductivity and long-range
antiferromagnetic (AFM) order coexist. The broad magnetic spectrum found in the
normal state develops into a magnetic resonance feature below TC that has
appreciable dispersion along c-axis with a bandwidth of 3-4 meV. This is in
contrast to the optimally doped x = 8.0% composition, with no long-range AFM
order, where the resonance exhibits a much weaker dispersion [see Lumsden et
al. Phys. Rev. Lett. 102, 107005 (2009)]. The results suggest that the
resonance dispersion arises from interlayer spin correlations present in the
AFM ordered state.",1002.3350v1
2010-03-19,Effect of pressure on the Electron Spin Resonance of a Heavy-Fermion metal,"We investigate the electron-spin resonance (ESR) phenomenon in the
heavy-fermion metal YbRh2Si2 by applying hydrostatic pressure up to 3 GPa and
by inducing internal pressure on the Yb site chemically in Yb(Rh1-xCox)2Si2
samples. We found that the increase in pressure, reducing the hybridization
between 4f and conduction electrons, leads to a remarkable change in the
temperature dependence of the g factor and broadens the ESR line. We relate the
differences between the effect of internal and external pressure on the low
temperature ESR parameters to the disorder induced by Co doping. The pressure
effects on the Yb3+ related resonance in YbRh2Si2 again manifest its local
character when compared with the resonance of diluted Gd in heavy-fermion
metals.",1003.3756v2
2010-04-07,Dimer Smectic in Extended Quantum Dimer Model -approach from pseudo S=1 Hamiltonian-,"We extend Quantum Dimer Model (QDM) introduced by Rokhsar and Kivelson in
such a way that the model includes resonance processes on larger loops. The
strategy is to first construct a pseudo spin Hamiltonian which is defined not
by the S =1/2 but by the S=1 representation and then establish the
correspondence between the pseudo-spin-1 configurations and those of dimers.
The standard QDM keeps only the lowest resonance processes for pairs of
parallel dimers and its validity in describing the realistic spin systems is
not obvious. Our extended QDM (EQDM) improves this point and contains a novel
resonance term, which is equivalent to two successive actions of the familiar
parallel dimer resonance. For a certain choice of the coupling constants, our
model exhibits three exotic valence-bond phases (herringbone, checkerboard and
'dimer smectic') in the ground state, which meet at a triple point. The
checkerboard phase has four-fold rotational symmetry, while the dimer smectic
is characterized by partial ordering only in one of the two directions. In the
dimer smectic phase, we investigate the dimer-dimer correlation by using an
analogy to random walks.",1004.1040v3
2010-09-20,Quasi-Resonant Theory of Tidal Interactions,"When a spinning system experiences a transient gravitational encounter with
an external perturber, a quasi-resonance occurs if the spin frequency of the
victim matches the peak orbital frequency of the perturber. Such encounters are
responsible for the formation of long tails and bridges of stars during galaxy
collisions. For high-speed encounters, the resulting velocity perturbations can
be described within the impulse approximation. The traditional impulse
approximation, however, does not distinguish between prograde and retrograde
encounters, and therefore completely misses the resonant response. Here, using
perturbation theory, we compute the effects of quasi-resonant phenomena on
stars orbiting within a disk. Explicit expressions are derived for the velocity
and energy change to the stars induced by tidal forces from an external
gravitational perturber passing either on a straight line or parabolic orbit.
Comparisons with numerical restricted three-body calculations illustrate the
applicability of our analysis.",1009.3927v1
2011-08-08,Magnetically tunable Feshbach resonances in ultracold Li-Yb mixtures,"We investigate the possibility of forming Li+Yb ultracold molecules by
magnetoassociation in mixtures of ultracold atoms. We find that magnetically
tunable Feshbach resonances exist, but are extremely narrow for even-mass
ytterbium isotopes, which all have zero spin. For odd-mass Yb isotopes,
however, there is a new mechanism due to hyperfine coupling between the
electron spin and the Yb nuclear magnetic moment. This mechanism produces
Feshbach resonances for fermionic Yb isotopes that can be more than 2 orders of
magnitude larger than for the bosonic counterparts.",1108.1827v2
2012-05-22,Resonances in 28Si+28Si. II,"Resonances observed in the 28Si+28Si collision are studied by the molecular
model. In the preceding paper, it is clarified that at high spins in 28Si+28Si
(oblate-oblate system), the stable dinuclear configuration of the system is
equator-equator touching one, and that the axially asymmetric shape of the
stable configuration of 28Si+28Si gives rise to a wobbling motion ($K$-mixing).
There, the normal modes around the equilibrium have been solved and various
excited states have been obtained. Those states are expected to be the origin
of a large number of resonances observed. Hence their physical quantities are
analyzed theoretically. The results are compared with the recent experiment
performed in Strasbourg and turn out to be in good agreement with the data.
Disalignments between the orbital angular momentum and the spins of the
constituent 28Si nuclei in the resonance state are clarified. Moreover the
analyses of the angular correlations indicate characteristic features for each
normal-mode excitation. Thus it is possible to identify the modes, and a
systematic experimental study of angular correlation measurements is desired.",1205.4992v1
2012-10-09,Micromagnetic theory of spin relaxation and ferromagnetic resonance in multilayered metallic films,"Spin relaxation in the ultrathin metallic films of stacked microelectronic
devices is investigated on the basis of a modified Landau-Lifshitz equation of
micromagnetic dynamics in which the damping torque is treated as originating
from the coupling between precessing magnetization-vector and the introduced
stress-tensors of intrinsic and extrinsic magnetic anisotropy. Particular
attention is given to the time of exponential relaxation and ferromagnetic
resonance linewidth which are derived in analytic form from the equation of
magnetization energy loss and Gabor uncertainty relation between the
full-width-at-half-maximum in resonance-shaped line and lifetime of resonance
excitation. The potential of developed theory is briefly discussed in the
context of recent measurements.",1210.2609v3
2012-10-20,Light narrowing of magnetic resonances in ensembles of nitrogen-vacancy centers in diamond,"We investigate optically detected magnetic resonance signals from an ensemble
of nitrogen-vacancy centers in diamond. The signals are measured for different
light powers and microwave powers, and the contrast and linewidth of the
magnetic-resonance signals are extracted. For a wide range of experimental
settings of the microwave and light powers, the linewidth decreases with
increasing light power, and more than a factor of two ""light narrowing"" is
observed.Furthermore, we identify that spin-spin interaction between
nitrogen-vacancy centers and substitutional nitrogen atoms in the diamond leads
to changes in the lineshape and the linewidth of the optically detected
magnetic-resonance signals. Finally, the importance of the light-narrowing
effect for optimizing the sensitivity of magnetic field measurements is
discussed.",1210.5574v1
2013-05-29,Ultrasensitive force detection with a nanotube mechanical resonator,"Since the advent of atomic force microscopy, mechanical resonators have been
used to study a wide variety of phenomena, such as the dynamics of individual
electron spins, persistent currents in normal metal rings, and the Casimir
force. Key to these experiments is the ability to measure weak forces. Here, we
report on force sensing experiments with a sensitivity of 12 zN Hz^(-1/2) at a
temperature of 1.2 K using a resonator made of a carbon nanotube. An
ultra-sensitive method based on cross-correlated electrical noise measurements,
in combination with parametric downconversion, is used to detect the
low-amplitude vibrations of the nanotube induced by weak forces. The force
sensitivity is quantified by applying a known capacitive force. This detection
method also allows us to measure the Brownian vibrations of the nanotube down
to cryogenic temperatures. Force sensing with nanotube resonators offers new
opportunities for detecting and manipulating individual nuclear spins as well
as for magnetometry measurements.",1305.6887v1
2013-08-14,The EDMR Microscope - Combining Conductive Atomic Force Microscopy with Electrically Detected Magnetic Resonance,"We present the design and implementation of a scanning probe microscope,
which combines electrically detected magnetic resonance (EDMR) and
(photo-)conductive atomic force microscopy ((p)cAFM). The integration of a
3-loop 2-gap X-band microwave resonator into an AFM allows the use of
conductive AFM tips as a movable contact for EDMR experiments. The optical
readout of the AFM cantilever is based on an infrared laser to avoid
disturbances of current measurements by absorption of straylight of the
detection laser. Using amorphous silicon thin film samples with varying defect
densities, the capability to detect a spatial EDMR contrast is demonstrated.
Resonant current changes as low as 20 fA can be detected, allowing the method
to realize a spin sensitivity of 8*10^6 spins/Hz^0.5 at room temperature.",1308.3167v1
2013-08-27,Resonances from Quiver Theories at the LHC,"We consider the collider signals of spin-one resonances present in
full-hierarchy quiver theories of electroweak symmetry breaking. These
four-dimensional theories result from the deconstruction of warped extra
dimensional models and have very distinct phenomenological features when the
number of sites is small. We study a class of generic scenarios in these
theories where the color gauge group as well as the electroweak sector,
propagate in the quiver diagram. These scenarios correspond to various specific
models of electroweak symmetry breaking and fermion masses. We focus on the
minimum resonant content and its main features: the presence of heavy and
narrow spin one resonances. We derive bounds from the LHC data on the
color-octet and color-singlet excited gauge bosons from their decays to jets
and top pairs, and show their dependence on the number of sites in the quiver.
We also compare them with the bounds derived from flavor violation.",1308.5988v1
2013-10-17,Double neutron spin resonances and gap anisotropy in underdoped superconducting NaFe0.985Co0.015As,"We use inelastic neutron scattering to show that superconductivity in
electron-underdoped NaFe0.985Co0.015As induces a dispersive sharp resonance
near Er1 = 3:25 meV and a broad dis- persionless mode at Er2 = 6 meV. However,
similar measurements on overdoped superconducting NaFe0:955Co0:045As find only
a single sharp resonance at Er = 7 meV. We connect these results with the
observations of angle-resolved photoemission spectroscopy that the
superconducting gaps in the electron Fermi pockets are anisotropic in the
underdoped material but become isotropic in the overdoped case. Our analysis
indicates that both the double neutron spin resonances and gap anisotropy
originate from the orbital dependence of the superconducting pairing in the
iron pnic- tides. Our discovery also shows the importance of the inelastic
neutron scattering in detecting the multiorbital superconducting gap structures
of iron pnictides.",1310.4817v1
2014-02-18,Optics of spin-noise-induced gyrotropy of asymmetric microcavity,"The optical gyrotropy noise of a high-finesse semiconductor Bragg microcavity
with an embedded quantum well (QW) is studied at different detunings of the
photon mode and the QW exciton resonances. A strong suppression of the noise
magnitude for the photon mode frequencies lying above exciton resonances is
found. We show that such a critical behavior of the observed optical noise
power is specific of asymmetric Fabry-Perot resonators. As follows from our
analysis, at a certain level of intracavity loss, the reflectivity of the
asymmetric resonator vanishes, while the polarimetric sensitivity to the
gyrotropy changes dramatically when moving across the critical point. The
results of model calculations are in a good agreement with our experimental
data on the spin noise in a single-quantum-well microcavity and are confirmed
also by the spectra of the photo-induced Kerr rotation in the pump-probe
experiments.",1402.4264v1
2014-10-08,"Resonance dynamics in the coherent $η$ meson production in the $(p,p^\prime)$ reaction on the spin-isospin saturated nucleus","For the forward going proton and $\eta$ meson, the coherent $\eta$ meson
production in the $(p,p^\prime)$ reaction on the spin-isospin saturated nucleus
occurs only due to the $\eta$ meson exchange interaction between the beam
proton and nucleus. In this process, the nucleon in the nucleus can be excited
to resonances $N^*$ and the $\eta$ meson in the final state can arise due to
$N^* \to N\eta$. We investigate the dynamics of resonances, including nucleon
Born terms, and their interferences in the coherently added cross section of
this reaction. We discuss the importance of $N(1520)$ resonance and show the
sensitivity of the cross section to the hadron nucleus interaction.",1410.2062v1
2015-01-30,Microscopic properties of degradation-free capped GdN thin films studied by Electron Spin Resonance,"The microscopic magnetic properties of high-quality GdN thin films have been
investigated by electron spin resonance (ESR) and ferromagnetic resonance (FMR)
measurements. Detailed temperature dependence ESR measurements have shown the
existence of two ferromagnetic components at lower temperatures which was not
clear from the previous magnetization measurements. The temperature, where the
resonance shift occurs for the major ferromagnetic component, seems to be
consistent with the Curie temperature obtained from the previous magnetization
measurement. On the other hand, the divergence of line width is observed around
57 K for the minor ferromagnetic component. The magnetic anisotropies of GdN
thin films have been obtained by the analysis of FMR angular dependence
observed at 4.2 K. Combining the X-ray diffraction results, the correlation
between the magnetic anisotropies and the lattice constants is discussed.",1501.07672v1
2015-02-19,Exciton-polaron complexes in pulsed electrically-detected magnetic resonance,"Several microscopic pathways have been proposed to explain the large magnetic
effects observed in organic semiconductors, but identifying and characterising
which microscopic process actually influences the overall magnetic field
response is challenging. Pulsed electrically-detected magnetic resonance
provides an ideal platform for this task as it intrinsically monitors the
charge carriers of interest and provides dynamical information which is
inaccessible through conventional magnetoconductance measurements. Here we
develop a general time domain theory to describe the spin-dependent reaction of
exciton-charge complexes following the coherent manipulation of paramagnetic
centers through electron spin resonance. A general Hamiltonian is treated, and
it is shown that the transition frequencies and resonance positions of the
exciton-polaron complex can be used to estimate inter-species coupling. This
work also provides a general formalism for analysing multi-pulse experiments
which can be used to extract relaxation and transport rates.",1502.05470v1
2015-08-05,Exact transition probabilities for a linear sweep through a Kramers-Kronig resonance,"We consider a localized electronic spin controlled by a circularly polarized
optical beam and an external magnetic field. When the frequency of the beam is
tuned near an optical resonance with a continuum of higher energy states,
effective magnetic fields are induced on the two-level system via the Inverse
Faraday Effect. We explore the process in which the frequency of the beam is
made linearly time-dependent so that it sweeps through the optical resonance,
starting and ending at the values far away from it. In addition to changes of
spin states, Kramers-Kronig relations guarantee that a localized electron can
also escape into a continuum of states. We argue that probabilities of
transitions between different possible electronic states after such a sweep of
the optical frequency can be found exactly regardless the shape of the
resonance. We also discuss extension of our results to multistate systems.",1508.01213v1
2016-10-11,Magnetic resonance with squeezed microwaves,"Vacuum fluctuations of the electromagnetic field set a fundamental limit to
the sensitivity of a variety of measurements, including magnetic resonance
spectroscopy. We report the use of squeezed microwave fields, which are
engineered quantum states of light for which fluctuations in one field
quadrature are reduced below the vacuum level, to enhance the detection
sensitivity of an ensemble of electronic spins at millikelvin temperatures.} By
shining a squeezed vacuum state on the input port of a microwave resonator
containing the spins, we obtain a $1.2$\,dB noise reduction at the spectrometer
output compared to the case of a vacuum input. This result constitutes a proof
of principle of the application of quantum metrology to magnetic resonance
spectroscopy.",1610.03329v2
2017-08-09,Enormous sample scale-up from nanoliter to microliter in high field liquid state dynamic nuclear polarization,"Dynamic nuclear polarization (DNP) enhances nuclear magnetic resonance (NMR)
signals by transferring electron spin polarization to nuclei. As DNP requires
microwave magnetic fields B1 strong enough to saturate electron spins,
microwave resonators are generally used to achieve a sufficient B1, at the
expense of restricting the sample size. Higher fields improve NMR sensitivity
and resolution. However, resonators at 9 T for example can only hold
nano-liters (nL). Larger volumes are possible by avoiding resonators, but the
higher power needed to reach B1 is likely to evaporate the sample. Here, we
demonstrate a breakthrough in liquid state DNP at 9 T, boosting the sample size
to the microliter range. We could use high-power (70 W) microwaves thanks to a
planar probe designed to alleviate dielectric heating. We enhanced the 1H NMR
signal intensity of 2 uL of liquid water by a factor of 14, while maintaining
the water temperature below 40 degree Celsius.",1708.02800v1
2017-08-13,Experimental study of antiferromagnetic resonance in noncollinear antiferromagnet Mn$_{3}$Al$_{2}$Ge$_{3}$O$_{12}$,"We have measured antiferromagnetic resonance (AFMR) frequency-field
dependences for aluminum-manganese garnet Mn$_{3}$Al$_{2}$Ge$_{3}$O$_{12}$ at
frequencies from 1 to 125 GHz and at the fields up to 60 kOe. Three AFMR modes
were observed for all orientations, their zero field gaps are about 40 and 70
GHz. Andreev-Marchenko hydrodynamic theory [Sov. Phys. Usp. 130, 39 (1980)]
well describes experimental frequency-field dependences. We have observed
hysteresis of resonance absorption as well as history dependence of resonance
absorption near gap frequencies below 10 kOe in all three measured field
orientations, which are supposedly due to the sample domain structure.
Observation of the AFMR signal at the frequencies from 1 to 5 GHz allows to
estimate repulsion of nuclear and electron modes of spin precession in the
vicinity of spin-reorientation transition at H||[100].",1708.03961v1
2017-11-15,Angle-dependent electron spin resonance of YbRh$_2$Si$_2$ measured with planar microwave resonators and in-situ rotation,"We present a new experimental approach to investigate the magnetic properties
of the anisotropic heavy-fermion system YbRh$_2$Si$_2$ as a function of
crystallographic orientation. Angle-dependent electron spin resonance (ESR)
measurements are performed at a low temperature of 1.6 K and at an ESR
frequency of 4.4 GHz utilizing a superconducting planar microwave resonator in
a $^4$He-cryostat in combination with in-situ sample rotation. The obtained ESR
g-factor of YbRh$_2$Si$_2$ as a function of the crystallographic angle is
consistent with results of previous measurements using conventional ESR
spectrometers at higher frequencies and fields. Perspectives to implement this
experimental approach into a dilution refrigerator and to reach the
magnetically ordered phase of YbRh$_2$Si$_2$ are discussed.",1711.05759v1
2018-06-20,Cyclotron and combined phonon-assisted resonances in double-well heterostructure In$_{0.65}$Ga$_{0.35}$As/In$_{0.52}$Al$_{0.48}$As at megagauss magnetic fields,"Experiments on resonances of conduction electrons in InGaAs/InAlAs double
quantum wells at megagauss magnetic fields in the Faraday geometry are
reported. We observe new cyclotron resonances assisted by emission of InAs-like
and GaAs-like optic phonons and a combined (cyclotron-spin) resonance assisted
by emission of InAs-like phonon. The observations are very well described for
three laser frequencies with the use of an eight-band (three level)
$\textbf{k}\cdot \textbf{p}$ model, taking into account position- and
energy-dependent effective masses and spin g-factors. It is indicated that the
new observations are possible due to the application very high magnetic fields.",1806.07825v3
2018-06-20,Magnetic field dependence of antiferromagnetic resonance in NiO,"We report on measurements of magnetic field and temperature dependence of
antiferromagnetic resonances in the prototypical antiferromagnet NiO. The
frequencies of the magnetic resonances in the vicinity of 1 THz have been
determined in the time-domain via time-resolved Faraday measurements after
selective excitation by narrow-band superradiant terahertz (THz) pulses at
temperatures down to 3K and in magnetic fields up to 10 T. The measurements
reveal two antiferromagnetic resonance modes, which can be distinguished by
their characteristic magnetic field dependencies. The nature of the two modes
is discussed by comparison to an eight-sublattice antiferromagnetic model,
which includes superexchange between the next-nearest-neighbor Ni spins,
magnetic dipolar interactions, cubic magneto-crystalline anisotropy, and Zeeman
interaction with the external magnetic field. Our study indicates that a
two-sublattice model is insufficient for the description of spin dynamics in
NiO, while the magnetic-dipolar interactions and magneto-crystalline anisotropy
play important roles.",1806.07968v1
2017-05-19,Enhancing Kondo Coupling in Alkaline-Earth Atomic Gases with Confinement-induced Resonances in Mixed Dimensions,"The Kondo effect describes the spin-exchanging interaction between localized
impurity and the itinerant fermions. The ultracold alkaline-earth atomic gas
provides a natural platform for quantum simulation of the Kondo model,
utilizing its long-lived clock state and the nuclear-spin exchanging
interaction between the clock state and the ground state. One of the key issue
now is whether the Kondo temperature can be high enough to be reached in
current experiment, for which we have proposed using a transverse confinement
to confine atoms into a one-dimensional tube and to utilize the
confinement-induced resonance to enhance the Kondo coupling. In this work, we
further consider the $1+0$ dimensional scattering problem when the clock state
is further confined by an axial harmonic confinement. We show that this axial
confinement for the clock state atoms not only plays a role for localizing
them, but also can act as an additional control knob to reach the
confinement-induced resonance. We show that by combining both the transverse
and the axial confinements, the confinement-induced resonance can be reached in
the practical conditions and the Kondo effect can be attainable in this system.",1705.06878v1
2020-04-03,Resonant Tunneling Anisotropic Magnetoresistance Induced by Magnetic Proximity,"We reveal that the interplay between Rashba spin-orbit coupling and
proximity-induced magnetization in a two-dimensional electron gas leads to
peculiar transport properties and large anisotropy of magnetoresistance. While
the related tunneling anisotropic magnetoresistance (TAMR) has been extensively
studied before, we predict an effect with a different origin arising from the
evolution of a resonant condition with the in-plane rotation of magnetization
and having a much larger magnitude. The resonances in the tunneling emerge from
a spin-parity-time symmetry of the scattering states. However, such a symmetry
is generally absent from the system itself and only appears for certain
parameter values. Without resonant behavior in the topological surface states
of a proximitized three-dimensional topological insulator (TI), TAMR
measurements can readily distinguish them from often misinterpreted trivial
Rashba-like states inherent to many TIs.",2004.03713v2
2020-04-14,Probing photo-induced rearrangements in the NdNiO$_{3}$ magnetic spiral with polarization-sensitive ultrafast resonant soft x-ray scattering,"We use resonant soft X-ray diffraction to track the photo-induced dynamics of
the antiferromagnetic structure in a NdNiO$_{3}$ thin film. Femtosecond laser
pulses with a photon energy of 0.61 eV, resonant with electron transfer between
long-bond and short-bond nickel sites, are used to excite the material and
drive an ultrafast insulator-metal transition. Polarization sensitive soft
X-ray diffraction, resonant to the nickel L$_{3}$-edge, then probes the
evolution of the underlying magnetic spiral as a function of time delay with 80
picosecond time resolution. By modelling the azimuthal dependence of the
scattered intensity for different linear X-ray polarizations, we benchmark the
changes of the local magnetic moments and the spin alignment. The measured
changes are consistent with a reduction of the long-bond site magnetic moments
and an alignment of the spins towards a more collinear structure at early time
delays.",2004.06752v2
2019-05-03,Diamond Phononic Crystal Spin-Mechanical Resonators with Spectrally Stable Nitrogen Vacancy Centers,"We report the design and fabrication of diamond spin-mechanical resonators
embedded in a two-dimensional (2D) phononic crystal square lattice. The
rectangular resonator features GHz in-plane compression modes protected by the
phononic band gap of the square lattice. A membrane-in-bulk approach is
developed for the fabrication of the suspended 2D structure. This approach
overcomes the limitations of the existing approaches, which are either
incompatible with the necessary high-temperature thermal annealing or
unsuitable for 2D structures with the required feature size. Graded soft oxygen
etching, with the etching rate decreased gradually to below 1 nm/minute, is
used to remove defective surface layers damaged by reactive ion etching.
Combining the graded etching with other established surface treatment
techniques reduces the optical linewidth of nitrogen vacancy centers in
resonators with a thickness below 1 micron to as narrow as 330 MHz.",1905.01251v1
2020-03-25,Anisotropic effect of a magnetic field on the neutron spin resonance in FeSe,"We use inelastic neutron scattering to study the effect of a magnetic field
on the neutron spin resonance (Er = 3.6 meV) of superconducting FeSe (Tc = 9
K). While a field aligned along the in-plane direction broadens and suppresses
the resonance, a c-axis aligned field does so much more efficiently, consistent
with the anisotropic field-induced suppression of the superfluid density from
the heat capacity measurements. These results suggest that the resonance in
FeSe is associated with the superconducting electrons arising from orbital
selective quasi-particle excitations between the hole and electron Fermi
surfaces.",2003.11488v1
2021-02-25,"Angular Distributions, Polarization Observables, Spin Density Matrices and Statistical Tensors in Photoproduction of Two Pseudoscalar Mesons off a Nucleon","In two meson photoproduction off a nucleon, for the case in which two of the
three final state hadrons are products of the decay of an intermediate
resonance, general expressions for its decay distribution and for polarization
observables are derived in a model independent way. These are functions of
either the spin density matrix elements (SDME's) or statistical tensors of the
resonance, and the angles of its decay products. The expressions are general
enough that it also describes cases where more than one resonance of arbitrary
quantum numbers contributes, including interference effects. They can therefore
be used to extract the SDME's or statistical tensors of the resonances that
contribute to the reaction.",2102.13104v1
2021-08-17,Relativistic quantum-mechanical versus classical magnetic resonant scattering cross sections,"Radiative transfer calculations in strong (few $\times 10^{12}$ G) magnetic
fields, observed in X-ray pulsars, require accurate resonant differential
scattering cross sections. Such cross sections exist, but they are quite
cumbersome. Here we compare the classical (non-relativistic) with the
quantum-mechanical (relativistic) resonant differential scattering cross
sections and offer a prescription for the use of the much simpler classical
expressions with impressively accurate results. We have expanded the
quantum-mechanical differential cross sections and kept terms up to first order
in $\epsilon \equiv E/m_ec^2$ and $B \equiv {\cal B}/{\cal B}_{cr}$, where $E$
is the photon energy and ${\cal B}_{cr}$ is the critical magnetic field, and
recovered the classical differential cross sections plus terms that are due to
spin flip, which is a pure quantum-mechanical phenomenon. Adding by hand the
spin-flip terms to the polarization-dependent classical differential cross
sections, we find that they are in excellent agreement with the quantum
mechanical ones for all energies near resonance and all angles. We have plotted
both of them and the agreement is impressive. We give a prescription for the
use of the classical differential cross sections that guarantees very accurate
results.",2108.07568v1
2017-01-14,Multichannel Molecular State and Rectified Short-range Boundary Condition for Spin-orbit Coupled Ultracold Fermions Near p-wave Resonances,"We study the interplay of spin-orbit coupling (SOC) and strong p-wave
interaction to the scattering property of spin-1/2 ultracold Fermi gases. Based
on a two-channel square-well potential generating p-wave resonance, we show
that the presence of an isotropic SOC, even for its length much longer than the
potential range, can greatly modify the p-wave short-range boundary
condition(BC). As a result, the conventional p-wave BC cannot predict the
induced molecules near p-wave resonance, which can be fully destroyed to vanish
due to strong interference between s- and p-wave channels. By analyzing the
intrinsic reasons for the breakdown of conventional BC, we propose a new p-wave
BC that can excellently reproduce the exact molecule solutions and also equally
apply for a wide class of single-particle potentials besides SOC. This work
reveals the significant effect of SOC to both the short- and long-range
properties of fermions near p-wave resonance, paving the way for future
exploring interesting few- and many-body physics in such system.",1701.03857v2
2019-07-25,Splitting of antiferromagnetic resonance modes in the quasi-two-dimensional collinear antiferromagnet Cu(en)(H$_2$O)$_2$SO$_4$,"Low-temperature magnetic resonance study of the quasi-two-dimensional
antiferromagnet Cu(en)(H$_2$O)$_2$SO$_4$ (en = C$_2$H$_8$N$_2$) was performed
down to 0.45~K. This compound orders antiferromagnetically at 0.9K. The
analysis of the resonance data within the hydrodynamic approach allowed to
identify anisotropy axes and to estimate the anisotropy parameters for the
antiferromagnetic phase. Dipolar spin-spin coupling turns out to be the main
contribution to the anisotropy of the antiferromagnetic phase. The splitting of
the resonance modes and its non-monotonous dependency on the applied frequency
was observed below 0.6K in all three field orientations. Several models were
discussed to explain the origin of the nontrivial splitting and the existence
of inequivalent magnetic subsystems in Cu(en)(H$_2$O)$_2$SO$_4$ was chosen as
the most probable source.",1907.11140v2
2019-08-03,Nucleon resonances in $γp \to ωp$ reaction,"The most recent high-precision data on spin observables $\Sigma$, $T$, $P'$,
$E$, $F$ and $H$ reported by the CLAS Collaboration together with the previous
data on differential cross sections and spin-density-matrix elements reported
by the CLAS, A2, GRAAL, SAPHIR and CBELSA/TAPS Collaborations for the reaction
$\gamma p \to \omega p$ are analyzed within an effective Lagrangian approach.
The reaction amplitude is constructed by considering the $t$-channel $\pi$ and
$\eta$ exchanges, the $s$-channel nucleon and nucleon resonances exchanges, the
$u$-channel nucleon exchange and the generalized contact current. The latter
accounts effectively for the interaction current and ensures that the full
photoproduction amplitude is gauge invariant. It is shown that all the
available CLAS data can be satisfactorily described by considering the
$N(1520)3/2^-$, $N(1700)3/2^-$, $N(1720)3/2^+$, $N(1860)5/2^+$, $N(1875)3/2^-$,
$N(1895)1/2^-$ and $N(2060)5/2^-$ resonances in the $s$-channel. The parameters
of these resonances are extracted and compared with those quoted by PDG.",1908.01139v2
2021-09-29,Insights into the nature of the $P_{cs}(4459)$,"We study the nature of the recently observed $P_{cs}(4459)$ by the LHCb
collaboration by employing three methods based on the elastic effective-range
expansion and the resulting size of the effective-range, the saturation of the
compositeness relation and width of the resonance, and a direct fit to data
involving the channels $J/\psi\Lambda$, $\Xi'_c\bar{D}$ and $\Xi_c\bar{D}^*$.
We have also considered the addition of a CDD pole but this scenario can be
discarded. Our different analyses clearly indicate the molecular nature of the
$P_{cs}(4459)$ with a clear $\Xi_c\bar{D}^*$ dominant component. In relation
with heavy-quark-spin symmetry our results also favor the actual existence of
two resonances with $J=1/2$ (the lighter one) and $3/2$ (the heavier one) in
the energy region of the $P_{cs}(4459)$. In the scenario of two-resonance for
the $P_{cs}(4459)$, the inclusion of the $\Xi_c'\bar{D}$ channel is required
for the their mass splitting and it allows one to determine the spin structures
of the two resonances.",2109.14237v1
2021-11-02,Nuclear electric resonance,"Nuclear-spin qubits have long coherence time and are desirably applied into
quantum information processing. However, the existing methods either fail to
address single nucleus (such as nuclear magnetic resonance), or severely affect
nuclear coherence time (such as electrical nuclear manipulation based on
hyperfine stark effect, ENMHSE). Here we propose an electrical nuclear
manipulation called nuclear electric resonance which can on the one hand
address the single nuclear qubit, and on the other keep the long coherence
time. Applying this, we construct universal quantum gates with external
electric field. These universal gates are practicable for arbitrary $S\ge 1$
spin nuclei. Given the much longer coherence time of nuclear electric
resonance, we improve the number of single-qubit operations by three orders of
magnitude compared with that of ENMHSE.",2111.01424v2
2021-11-09,Accurate measurement of atomic magnetic moments by minimizing the tip magnetic field in STM-based electron paramagnetic resonance,"Electron paramagnetic resonance (EPR) performed with a scanning tunneling
microscope (STM) allows for probing the spin excitation of single atomic
species with MHz energy resolution. One of the basic applications of
conventional EPR is the precise determination of magnetic moments. However, in
an STM, the local magnetic fields of the spin-polarized tip can introduce
systematic errors in the measurement of the magnetic moments by EPR. We propose
to solve this issue by finding tip-sample distances at which the EPR resonance
shift caused by the magnetic field of the tip is minimized. To this end, we
measure the dependence of the resonance field on the tip-sample distance at
different radiofrequencies and identify specific distances for which the true
magnetic moment is found. Additionally, we show that the tip's influence can be
averaged out by using magnetically bistable tips, which provide a complementary
method to accurately measure the magnetic moment of surface atoms using
EPR-STM.",2111.05043v1
2022-03-04,Resonance $X(4630)$,"We investigate the structure $X(4630)$ discovered by the LHCb collaboration
in the process $B^{+}\rightarrow J/\psi \phi K^{+}$ as a resonance in the $
J/\psi \phi $ mass distribution. We explore this resonance as a
diquark-antidiquark state $X=[cs][\overline{c}\overline{s}]$ with spin-parities
$J^{\mathrm{PC}}=1^{-+}$. Its mass and current coupling are calculated using
the QCD two-point sum rule method by taking into account vacuum condensates up
to dimension $10$. We also study decays of this tetraquark to mesons
$J/\psi\phi $, $\eta _{c}\eta ^{(\prime )}$, and $\chi _{c1}\eta ^{(\prime )}$,
and compute partial widths of these channels. To this end, we employ the
light-cone sum rule approach and technical methods of soft-meson approximation
to extract strong coupling at relevant tetraquark-meson-meson vertices. Our
predictions for the mass $m=(4632\pm 60)~\mathrm{MeV}$ and width
$\Gamma=(159\pm 31)~\mathrm{MeV}$ of $X$ are in a very nice agreement with
recent measurements of the LHCb collaboration. These results allow us to
interpret the resonance $X(4630)$ as the tetraquark $X$ with spin-parities
$J^{\mathrm{PC}}=1^{-+}$.",2203.02542v2
2022-06-29,"Comment on ""Electron spin resonance and collective excitations in magic-angle twisted bilayer graphene""","This comment pertains the recent manuscript by Morissette {\it et al.}
[arXiv:2206.08354v1]. The authors claim to have found signatures of collective
excitations in electron spin resonance experiments that would be linked to the
correlated structure of magic angle bilayer graphene. However, identical
resonance features have already been reported in previous works on mono- and
few-layer graphene, voiding their theoretical framework. A straight forward
theoretical picture within the single-particle topologically non-trivial band
structure of graphene delivers satisfactory explanations for the observation of
the resonant features and applies as well to the data presented by Morissette
{\it et al.}. However, this intuitive picture has been disregarded by the
authors.",2206.14628v1
2022-10-28,Resonant Spin Hall Effect of Light in Random Photonic Arrays,"It has been recently shown that the coherent component of light propagating
in transversally disordered media, the so-called coherent mode, exhibits an
optical spin Hall effect (SHE). In non-resonant materials, however, this
phenomenon shows up at a spatial scale much larger than the mean free path,
making its observation challenging due to the exponential attenuation of the
coherent mode. Here, we show that in disordered photonic arrays exhibiting Mie
resonances, the SHE on the contrary appears at a scale smaller than the mean
free path if one operates in the close vicinity of the lowest
transverse-magnetic resonance of the array. In combination with a weak
measurement, this gives rise to a giant SHE that should be observable in
optically-thin media. Furthermore, we show that by additionally exploiting the
cooperative emission of a flash of light following the abrupt extinction of the
incoming beam, one can achieve a time-dependent SHE, observable at large
optical thickness as well.",2210.16379v2
2023-02-08,Radiation pressure backaction on a hexagonal boron nitride nanomechanical resonator,"Hexagonal boron nitride (hBN) is a van der Waals material with excellent
mechanical properties hosting quantum emitters and optically active spin
defects, several of them being sensitive to strain. Establishing optomechanical
control of hBN will enable hybrid quantum devices that combine the spin degree
of freedom with the cavity optomechanical toolbox. In this letter, we report
the first observation of radiation pressure backaction at telecom wavelengths
with a hBN drum-head mechanical resonator. The thermomechanical motion of the
resonator is coupled to the optical mode of a high finesse fiber-based
Fabry-P\'erot microcavity in a membrane-in-the-middle configuration. We are
able to resolve the optical spring effect and optomechanical damping with a
single photon coupling strength of $g_0/2\pi = 1200$ Hz. Our results pave the
way for tailoring the mechanical properties of hBN resonators with light.",2302.04291v2
2023-06-29,Ultimate parameters of an all-optical MX resonance in Cs in ultra-weak magnetic field,"We present the results of studying the parameters of the magnetic MX
resonance in an all-optical sensor built according to the two-beam Bell-Bloom
scheme in nonzero ultra-weak magnetic fields in which the effects of
spin-exchange broadening suppression are partially manifested. We report on the
features of the resonance under these conditions. We also optimize the
resonance parameters to achieve maximum sensitivity in magnetoencephalographic
sensors. We demonstrate an improvement in the ultimate achievable sensitivity
of an all-optical MX sensor by a factor of four or more, which in our
experiment corresponds to a decrease from 13 to 3 fT/Hz1/2 in a volume of 0.13
cm3. We also report the effect of incomplete suppression of spin-exchange
broadening under conditions of strong transverse modulated optical pumping, and
propose a semi-empirical model to describe it.",2306.16924v2
2023-12-21,Improving magnetic-field resilience of NbTiN planar resonators using a hard-mask fabrication technique,"High-quality factor microwave resonators operating in a magnetic field are a
necessity for some quantum sensing applications and hybrid platforms. Losses in
microwave superconducting resonators can have several origins, including
microscopic defects, usually known as two-level-systems (TLS). Here, we
characterize the magnetic field response of NbTiN resonators patterned on
sapphire and observe clear absorption lines occurring at specific magnetic
fields. We identify the spin systems responsible for these features, including
a yet unreported spin with $g=1.85$ that we attribute to defects in the NbTiN
thin film. We develop mitigation strategies involving namely an aluminum etch
mask, resulting in maintaining quality factors above $Q>2 \times 10^5$ in the
range $0$-$0.3$ T.",2312.13703v1
2024-01-11,The spin-flip-induced quadrupole resonance in odd-$A$ exotic atoms,"We examine the possible existence of quadrupole resonances in exotic atoms
containing odd-$A$ nuclei. We find that the spin-flip of the de-exciting exotic
particle can induce a resonance, altering the orbital angular momentum of the
nucleus by one quanta. This process results in an excited nucleus with a
suppression in x-ray photon emissions during the exotic atom cascade. We
provide specific cases of antiprotonic atoms of stable elements where this
resonance effect is expected to occur. The study of this phenomena may provide
insight into the strong interaction of deeply bound antiprotonic states in the
proximity of the unpaired nucleon, and serve as a tool for probing short-lived
excited nuclear states.",2401.06063v2
2024-02-06,Theory of parametric resonance for discrete time crystals in fully-connected spin-cavity systems,"We pinpoint the conditions necessary for discrete time crystal (DTC)
formation in fully connected spin-cavity systems from the perspective of
parametric resonance by mapping these systems onto oscillator like models. We
elucidate the role of nonlinearity and dissipation by mapping the periodically
driven open Dicke model onto effective linear and nonlinear oscillator models,
while we analyze the effect of global symmetry breaking using the
Lipkin-Meshkov-Glick model with tunable anisotropy. We show that the system's
nonlinearity restrains the dynamics from becoming unbounded when driven
resonantly. On the other hand, dissipation keeps the oscillation amplitude of
the period-doubling instability fixed, which is a key feature of DTCs. The
presence of global symmetry breaking in the absence of driving is found to be
crucial in the parametric resonant activation of period-doubling response. We
provide analytic predictions for the resonant frequencies and amplitudes
leading to DTC formation for both systems using their respective oscillator
models.",2402.03729v2
2024-03-08,Damping Obliquities of Hot Jupiter Hosts by Resonance Locking,"When orbiting hotter stars, hot Jupiters are often highly inclined relative
to their host star equator planes. By contrast, hot Jupiters orbiting cooler
stars are more aligned. Prior attempts to explain this correlation between
stellar obliquity and effective temperature have proven problematic. We show
how resonance locking -- the coupling of the planet's orbit to a stellar
gravity mode (g mode) -- can solve this mystery. Cooler stars with their
radiative cores are more likely to be found with g-mode frequencies increased
substantially by core hydrogen burning. Strong frequency evolution in resonance
lock drives strong tidal evolution; locking to an axisymmetric g mode damps
semi-major axes, eccentricities, and as we show for the first time,
obliquities. Around cooler stars, hot Jupiters evolve into spin-orbit alignment
and avoid engulfment. Hotter stars lack radiative cores, and therefore preserve
congenital spin-orbit misalignments. We focus on resonance locks with
axisymmetric modes, supplementing our technical results with simple physical
interpretations, and show that non-axisymmetric modes also damp obliquity.",2403.05616v1
2013-04-16,An analysis method for transmission measurements of superconducting resonators with applications to quantum-regime dielectric-loss measurements,"Superconducting resonators provide a convenient way to measure loss tangents
of various dielectrics at low temperature. For the purpose of examining the
microscopic loss mechanisms in dielectrics, precise measurements of the
internal quality factor at different values of energy stored in the resonators
are required. Here, we present a consistent method to analyze a LC
superconducting resonator coupled to a transmission line. We first derive an
approximate expression for the transmission S-parameter $S_{21}$ based on a
complete circuit model. In the weak coupling limit, we show that the internal
quality factor is reliably determined by fitting the approximate form of
$S_{21}$. Since the voltage $V$ of the capacitor of the LC circuit is required
to determine the energy stored in the resonator, we next calculate the relation
between $V$ and the forward propagating wave voltage $V_{in}^+$. Due to the
dependence of the quality factor on voltage, $V$ is not simply proportional to
$V_{in}^+$. We find a self-consistent way to determine the relation between $V$
and $V_{in}^+$, which employs only the fitting parameters for $S_{21}$ and a
linear scaling factor. We then examine the resonator transmission in the cases
of port reflection and impedance mismatch. We find that resonator transmission
asymmetry is primarily due to the reflection from discontinuity in transmission
lines. We show that our analysis method to extract the internal quality factor
is robust in the non-ideal cases above. Finally, we show that the analysis
method on LC resonator can be generalize to arbitrary weakly coupled lumped and
distributed resonators. The generalization uses a systematic approximation on
the response function based on the pole and zero which are the closest to the
resonance frequency. This Closest Pole and Zero Method (CPZM) is a valuable
tool for analyzing physical measurements of high-Q resonators.",1304.4533v2
1996-12-31,Fluid Models for Kinetic Effects on Coherent Nonlinear Alfven Waves. II. Numerical Solutions,"The influence of various kinetic effects (e.g. Landau damping, diffusive and
collisional dissipation, and finite Larmor radius terms) on the nonlinear
evolution of finite amplitude Alfvenic wave trains in a finite-beta environment
is systematically investigated using a novel, kinetic nonlinear Schrodinger
(KNLS) equation. The dynamics of Alfven waves is sensitive to the sense of
polarization as well as the angle of propagation with respect to the ambient
magnetic field. Numerical solution for the case with Landau damping reveals the
formation of dissipative structures, which are quasi-stationary, S-polarized
directional (and rotational) discontinuities which self-organize from parallel
propagating, linearly polarized waves. Parallel propagating circularly
polarized packets evolve to a few circularly polarized Alfven harmonics on
large scales. Stationary arc-polarized rotational discontinuities form from
obliquely propagating waves. Collisional dissipation, even if weak, introduces
enhanced wave damping when beta is very close to unity. Cyclotron motion
effects on resonant particle interactions introduce cyclotron resonance into
the nonlinear Alfven wave dynamics.",9612018v1
2007-12-19,Enhanced Transmission of Light and Particle Waves through Subwavelength Nanoapertures by Far-Field Interference,"Subwavelength aperture arrays in thin metal films can enable enhanced
transmission of light and matter (atom) waves. The phenomenon relies on
resonant excitation and interference of the plasmon or matter waves on the
metal surface. We show a new mechanism that could provide a great resonant and
nonresonant transmission enhancement of the light or de Broglie particle waves
passed through the apertures not by the surface waves, but by the constructive
interference of diffracted waves (beams generated by the apertures) at the
detector placed in the far-field zone. In contrast to other models, the
mechanism depends neither on the nature (light or matter) of the beams
(continuous waves or pulses) nor on material and shape of the multiple-beam
source (arrays of 1-D and 2-D subwavelength apertures, fibers, dipoles or
atoms). The Wood anomalies in transmission spectra of gratings, a long standing
problem in optics, follow naturally from the interference properties of our
model. The new point is the prediction of the Wood anomaly in a classical
Young-type two-source system. The new mechanism could be interpreted as a
non-quantum analog of the superradiance emission of a subwavelength ensemble of
atoms (the light power and energy scales as the number of light-sources
squared, regardless of periodicity) predicted by the well-known Dicke quantum
model.",0712.3156v2
2008-04-18,"Solar off-limb line widths: Alfven waves, ion-cyclotron waves, and preferential heating","Alfven waves and ion-cyclotron absorption of high-frequency waves are
frequently brought into models devoted to coronal heating and fast solar-wind
acceleration. Signatures of ion-cyclotron resonance have already been observed
in situ in the solar wind (HELIOS spacecrafts) and, recently, in the upper
corona (UVCS/SOHO remote-sensing results). We propose a method to constrain
both the Alfven wave amplitude and the preferential heating induced by
ion-cyclotron resonance, above a partially developed polar coronal hole
observed with the SUMER/SOHO spectrometer. The instrumental stray light
contribution is first substracted from the spectra. By supposing that the
non-thermal velocity is related to the Alfven wave amplitude, it is constrained
through a density diagnostic and the gradient of the width of the Mg X 625 A
line. The temperatures of several coronal ions, as functions of the distance
above the limb, are then determined by substracting the non-thermal component
to the observed line widths. The effect of stray light explains the apparent
decrease with height in the width of several spectral lines, this decrease
usually starting about 0.1-0.2 Rs above the limb. This result rules out any
direct evidence of damping of the Alfven waves, often suggested by other
authors. We also find that the ions with the smallest charge-to-mass ratios are
the hottest ones at a fixed altitude and that they are subject to a stronger
heating, as compared to the others, between 57"" and 102"" above the limb. This
constitutes a serious clue to ion-cyclotron preferential heating.",0804.2987v1
2013-12-06,An Interpretation of Flare-Induced and Decayless Coronal-Loop Oscillations as Interference Patterns,"We present an alternative model of coronal-loop oscillations which considers
that the waves are trapped in a 2D waveguide formed by the entire arcade of
field lines. This differs from the standard 1D model which treats the waves as
the resonant oscillations of just the visible bundle of field lines. Within the
framework of our 2D model, the two types of oscillations that have been
observationally identified, flare-induced waves and ""decayless"" oscillations,
can both be attributed to MHD fast waves. The two components of the signal
differ only because of the duration and spatial extent of the source that
creates them. The flare-induced waves are generated by strong localized sources
of short duration, while the decayless background can be excited by a
continuous, stochastic source. Further, the oscillatory signal arising from a
localized, short-duration source can be interpreted as a pattern of
interference fringes produced by waves that have traveled diverse routes of
various pathlengths through the waveguide. The resulting amplitude of the
fringes slowly decays in time with an inverse square root dependence. The
details of the interference pattern depend on the shape of the arcade and the
spatial variation of the Alfv\'en speed. The rapid decay of this wave
component, which has previously been attributed to physical damping mechanisms
that remove energy from resonant oscillations, occurs as a natural consequence
of the interference process without the need for local dissipation.",1312.1922v1
2014-01-08,"General multicomponent Yajima-Oikawa system: Painlevé analysis, soliton solutions, and energy-sharing collisions","We consider the multicomponent Yajima-Oikawa (YO) system and show that the
two-component YO system can be derived in a physical setting of three-coupled
nonlinear Schr\""odinger (3-CNLS) type system by the asymptotic reduction
method. The derivation is further generalized to multicomponent case. This set
of equations describes the dynamics of nonlinear resonant interaction between
one-dimensional long-wave and multiple short-waves. The Painlev\'e analysis of
the general multicomponent YO system shows that the underlying set of evolution
equations is integrable for arbitrary nonlinearity coefficients which will
result in three different sets of equations corresponding to positive, negative
and mixed nonlinearity coefficients. We obtain general bright $N$-soliton
solution of multicomponent YO system in the Gram determinant form by using
Hirota's bilinearization method and explicitly analyze the one- and two-soliton
solutions of the multicomponent YO system for the above mentioned three choices
of nonlinearity coefficients. We also point out that the 3-CNLS system admits
special asymptotic solitons of bright, dark, anti-dark and grey types, when the
long-wave--short-wave resonance takes place. The short-wave component solitons
undergo two types of energy sharing collisions. The solitons appearing in the
long-wave component always exhibit elastic collision whereas that of short-wave
components exhibit standard elastic collisions only for specific choice of
parameters. We have also investigated the collision dynamics of asymptotic
solitons in the original 3-CNLS system. For completeness, we explore the
three-soliton interaction and demonstrate the pair-wise nature of collision and
unravel fascinating state restoration property.",1401.1579v1
2015-02-13,Magnetohydrodynamic kink waves in nonuniform solar flux tubes: phase mixing and energy cascade to small scales,"Magnetohydrodynamic (MHD) kink waves are ubiquitously observed in the solar
atmosphere. The propagation and damping of these waves may play relevant roles
for the transport and dissipation of energy in the solar atmospheric medium.
However, in the atmospheric plasma dissipation of transverse MHD wave energy by
viscosity or resistivity needs very small spatial scales to be efficient. Here,
we theoretically investigate the generation of small scales in nonuniform solar
magnetic flux tubes due to phase mixing of MHD kink waves. We go beyond the
usual approach based on the existence of a global quasi-mode that is damped in
time due to resonant absorption. Instead, we use a modal expansion to express
the MHD kink wave as a superposition of Alfv\'en continuum modes that are phase
mixed as time evolves. The comparison of the two techniques evidences that the
modal analysis is more physically transparent and describes both the damping of
global kink motions and the building up of small scales due to phase mixing. In
addition, we discuss that the processes of resonant absorption and phase mixing
are intimately linked. They represent two aspects of the same underlying
physical mechanism: the energy cascade from large scales to small scales due to
naturally occurring plasma and/or magnetic field inhomogeneities. This process
may provide the necessary scenario for efficient dissipation of transverse MHD
wave energy in the solar atmospheric plasma.",1502.03949v1
2015-06-05,Sub- and supercritical defect scattering in Schrödinger chains with higher-order hopping,"We theoretically analyze a discrete Schr\""odinger chain with hopping to the
first and second neighbors, as can be realized with zigzag arrangements of
optical waveguides or lattice sites for cold atoms. Already at moderate values,
the second-neighbor hopping has a strong impact on the band structure, leading
to the emergence of a new extremum located inside the band, accompanied by a
van Hove singularity in the density of states. The energy band is then divided
into a subcritical regime with the usual unique correspondence between wave
number and energy of the travelling waves, and a supercritical regime, in which
waves of different wave number are degenerate in energy. We study the
consequences of these features in a scattering setup, introducing a defect that
locally breaks the translational invariance. The notion of a local probability
current is generalized beyond the nearest-neighbor approximation and bound
states with energies outside the band are discussed. At subcritical energies
inside the band, an evanescent mode coexists with the travelling plane wave,
giving rise to resonance phenomena in scattering. At weak coupling to the
defect, we identify a prototypical Fano-Feshbach resonance of tunable shape and
provide analytical expressions for its profile parameters. At supercritical
energies, we observe coupling of the degenerate travelling waves, leading to an
intricate wave packet fragmentation dynamics. The corresponding branching
ratios are analyzed.",1506.01937v1
2016-09-30,Modelling observed decay-less oscillations as resonantly enhanced Kelvin-Helmholtz vortices from transverse MHD waves and their seismological application,"In the highly structured solar corona, resonant absorption is an unavoidable
mechanism of energy transfer from global transverse MHD waves to local
azimuthal Alfv\'en waves. Due to its localised nature, a direct detection of
this mechanism is extremely difficult. Yet, it is the leading theory explaining
the observed fast damping of the global transverse waves. However, at odds with
this theoretical prediction, recent observations indicate that in the low
amplitude regime such transverse MHD waves can also appear decay-less, a yet
unsolved phenomenon. Recent numerical work has shown that Kelvin-Helmholtz
instabilities (KHI) often accompany transverse MHD waves. In this work, we
combine 3D MHD simulations and forward modelling to show that for currently
achieved spatial resolution and observed small amplitudes, an apparent
decay-less oscillation is obtained. This effect results from the combination of
periodic brightenings produced by the KHI and the coherent motion of the KHI
vortices amplified by resonant absorption. Such effect is especially clear in
emission lines forming at temperatures that capture the boundary dynamics
rather than the core, and reflects the low damping character of the local
azimuthal Alfv\'en waves resonantly coupled to the kink mode. Due to phase
mixing, the detected period can vary depending on the emission line, with those
sensitive to the boundary having shorter periods than those sensitive to the
loop core. This allows to estimate the density contrast at the boundary.",1609.09716v1
2017-05-25,Elastic wave control beyond band-gaps: shaping the flow of waves in plates and half-spaces,"It is well known in metamaterials that local resonance and hybridization
phenomena dramatically influence the shape of dispersion curves; the
metasurface created by a cluster of resonators, subwavelength rods, atop an
elastic surface being an exemplar with these features. On this metasurface,
band-gaps, slow or fast waves, negative refraction and dynamic anisotropy can
all be observed by exploring frequencies and wavenumbers from the Floquet-Bloch
problem and by using the Brillouin zone. These extreme characteristics, when
appropriately engineered, can be used to design and control the propagation of
elastic waves along the metasurface. For the exemplar we consider, two
parameters are easily tuned: rod height and cluster periodicity. The height is
directly related to the band-gap frequency, and hence to the slow and fast
waves, while the periodicity is related to the appearance of dynamic
anisotropy. Playing with these two parameters generates a gallery of
metasurface designs to control the propagation of both flexural waves in plates
and surface Rayleigh waves for half-spaces. Scalability with respect to the
frequency and wavelength of the governing physical laws allows the application
of these concepts in very different fields and over a wide range of
lengthscales.",1705.09288v1
2016-12-15,Tidal dissipation by inertial waves in differentially rotating convective envelopes of low-mass stars,"Tidal interactions in close star-planet or binary star systems may excite
inertial waves (their restoring force is the Coriolis force) in the convective
region of the stars. The dissipation of these waves plays a prominent role in
the long-term orbital and rotational evolution of the bodies involved. If the
primary star rotates as a solid body, inertial waves have a Doppler-shifted
frequency restricted to the range $[-2\Omega, 2\Omega]$ ($\Omega$ being the
angular velocity of the star), and they can propagate in the entire convective
region. However, turbulent convection can sustain differential rotation with an
equatorial acceleration (as in the Sun) or deceleration that modifies the
frequency range and propagation domain of inertial waves and allows corotation
resonances for non-axisymmetric oscillations. In this work, we perform
numerical simulations of tidally excited inertial waves in a differentially
rotating convective envelope with a conical (or latitudinal) rotation profile.
The tidal forcing that we adopt contains spherical harmonics that correspond to
the case of a circular and coplanar orbit. We study the viscous dissipation of
the waves as a function of tidal frequency for various stellar masses and
differential rotation parameters, as well as its dependence on the turbulent
viscosity coefficient. We compare our results with previous studies assuming
solid-body rotation and point out the potential key role of corotation
resonances in the dynamical evolution of close-in star-planet or binary
systems.",1612.05071v1
2017-10-29,Kirigami-based Elastic Metamaterials with Anisotropic Mass Density for Subwavelength Flexural Wave Control,"A novel design of an elastic metamaterial with anisotropic mass density is
proposed to manipulate flexural waves at a subwavelength scale. The
three-dimensional metamaterial is inspired by kirigami, which can be easily
manufactured by cutting and folding a thin metallic plate. By attaching the
resonant kirigami structures periodically on the top of a host plate, a
metamaterial plate can be constructed without any perforation that degrades the
strength of the pristine plate. An analytical model is developed to understand
the working mechanism of the proposed elastic metamaterial and the dispersion
curves are calculated by using an extended plane wave expansion method. As a
result, we verify an anisotropic effective mass density stemming from the
coupling between the local resonance of the kirigami cells and the global
flexural wave propagations in the host plate. Finally, numerical simulations on
the directional flexural wave propagation in a two-dimensional array of
kirigami metamaterial as well as super-resolution imaging through an elastic
hyperlens are conducted to demonstrate the subwavelength-scale flexural wave
control abilities. The proposed kirigami-based metamaterial has the advantages
of no-perforation design and subwavelength flexural wave manipulation
capability, which can be highly useful for engineering applications including
non-destructive evaluations and structural health monitoring.",1710.10560v1
2020-11-18,Nonlinear Landau resonant interaction between kinetic Alfvén waves and thermal electrons: Excitation of time domain structures,"Phase space holes, double layers and other solitary electric field
structures, referred to as time domain structures (TDSs), often occur around
dipolarization fronts in the Earth's inner magnetosphere. They are considered
to be important because of their role in the dissipation of the injection
energy and their potential for significant particle scattering and
acceleration. Kinetic Alfv\'en waves are observed to be excited during
energetic particle injections, and are typically present in conjunction with
TDS observations. Despite the availability of a large number of spacecraft
observations, the origin of TDSs and their relation to kinetic Alfv\'en waves
remains poorly understood to date. Part of the difficulty arises from the vast
scale separations between kinetic Alfv\'en waves and TDSs. Here, we demonstrate
that TDSs can be excited by electrons in nonlinear Landau resonance with
kinetic Alfv\'en waves. These electrons get trapped by the parallel electric
field of kinetic Alfv\'en waves, form localized beam distributions, and
subsequently generate TDSs through beam instabilities. A big picture emerges as
follows: macroscale dipolarization fronts first transfer the ion flow (kinetic)
energy to kinetic Alfv\'en waves at intermediate scale, which further channel
the energy to TDSs at the microscale and eventually deposit the energy to the
thermal electrons in the form of heating. In this way, the ion flow energy
associated with dipolarization fronts is effectively dissipated in a cascade
from large to small scales in the inner magnetosphere.",2011.09071v1
2020-11-22,Adaptive nonreciprocal wave attenuation in linear piezoelectric metastructures shunted with one-way electrical transmission lines,"In contrary to elastic media, it is easy to attain one-way coupling feature
among electrical elements, which enables unidirectional transmission of
electrical wave. In this paper, we explore and exploit the interaction of a
piezoelectric beam with a one-way electrical transmission line to facilitate
nonreciprocal transmission of elastic wave in the linear fashion. Theoretical
dispersion analysis and numerical simulations are performed to reveal
transmission behaviors of elastic wave in the presented piezoelectric
metastructure. It is uncovered that, when the one-way electrical coupling
feature is introduced, local-resonance bandgaps are maintained in opposite
directions of the piezoelectric metastructure. However, the bandgap attenuation
capability in one direction is increased compared to conventional
local-resonance metastructures, in which no electrical coupling exists between
cells, while that in the other direction is decreased. Therefore, nonreciprocal
transmission of elastic wave emerges in this system due to the distinct bandgap
attenuation capability. It is also revealed that this sort of nonreciprocal
wave attenuation capability is adaptive with the one-way electrical coupling
coefficient and the resistance of electrical cells. An experimental set-up of
the piezoelectric metastructure is built and experimental results verify the
nonreciprocity property and its adaptiveness. Overall, the presented
piezoelectric metastructure provides a linear and concise approach to realize
adaptive nonreciprocal transmission of elastic wave.",2011.10993v3
2022-01-31,"How a realistic magnetosphere alters the polarizations of surface, fast magnetosonic, and Alfvén waves","System-scale magnetohydrodynamic (MHD) waves within Earth's magnetosphere are
often understood theoretically using box models. While these have been highly
instructive in understanding many fundamental features of the various wave
modes present, they neglect the complexities of geospace such as the
inhomogeneities and curvilinear geometries present. Here we show global MHD
simulations of resonant waves impulsively-excited by a solar wind pressure
pulse. Although many aspects of the surface, fast magnetosonic
(cavity/waveguide), and Alfv\'en modes present agree with the box and axially
symmetric dipole models, we find some predictions for large-scale waves are
significantly altered in a realistic magnetosphere. The radial ordering of fast
mode turning points and Alfv\'en resonant locations may be reversed even with
monotonic wave speeds. Additional nodes along field lines that are not present
in the displacement/velocity occur in both the perpendicular and compressional
components of the magnetic field. Close to the magnetopause the perpendicular
oscillations of the magnetic field have the opposite handedness to the
velocity. Finally, widely-used detection techniques for standing waves, both
across and along the field, can fail to identify their presence. We explain how
all these features arise from the MHD equations when accounting for a
non-uniform background field and propose modified methods which might be
applied to spacecraft observations.",2201.13152v1
2000-07-18,Dirac equation in Kerr geometry and its solution,"Chandrasekhar separated the Dirac equation for spinning and massive particles
in Kerr geometry into radial and angular parts. In the present review, we
present solutions of the complete wave equation and discuss how the Dirac wave
scatters off Kerr black holes. The eigenfunctions, eigenvalues and reflection
and transmission co-efficients are computed for different Kerr parameters. We
compare the solutions with several parameters to show how a spinning black hole
distinguishes mass and energy of incoming waves. Very close to the horizon, the
solutions become independent of the particle parameters indicating an
universality of the behaviour.",0007253v1
1993-11-24,Phason modes in spin-density wave in the presence of long-range Coulomb interaction,"We study the effect of long-range Coulomb interaction on the phason in
spin-density wave (SDW) within mean field theory. In the longitudinal limit and
in the absence of SDW pinning the phason is completely absorbed by the plasmon
due to the Anderson-Higgs mechanism. In the presence of SDW pinning or when the
wave vector {\bf q} is tilted from the chain direction, though the plasmon
still almost exhausts the optical sum rule, another optical mode appears at
$\omega < 2\Delta(T)$, with small optical weight. This low frequency mode below
the SDW gap may be accessible to electron energy loss spectroscopy (EELS).",9311056v1
1994-12-09,Quantum Hall Effect in Three-dimensional Field-Induced Spin Density Wave Phases with a Tilted Magnetic Field,"The quantum Hall effect in the three-dimensional anisotropic tight-binding
electrons is investigated in the field-induced spin density wave phases with a
magnetic field tilted to any direction. The Hall conductivity, $\sigma_{xy}$
and $\sigma_{xz}$, are shown to be quantized as a function of the wave vector
of FISDW, while $\sigma_{yz}$ stays zero, where $x$ is the most conducting
direction and $y$ and $z$ are perpendicular to $x$.",9412043v1
1998-04-03,Susceptibilities and Correlation Functions of the Anisotropic Spherical Model,"The static transverse and longitudinal correlation functions (CF) of a
3-dimensional ferromagnet are calculated for the exactly solvable anisotropic
spherical model (ASM) determined as the limit D \to \infty of the classical
D-component vector model. The results are nonequivalent to those for the
standard spherical model of Berlin and Kac even in the isotropic case. Whereas
the transverse CF has the usual Ornstein-Zernike form for small wave vectors,
the longitudinal CF shows a nontrivial behavior in the ordered region caused by
spin-wave fluctuations. In particular, in the isotropic case below T_c one has
S_{zz}(k) \propto 1/k (the result of the spin-wave theory) for k \lsim \kappa_m
\propto T_c-T.",9804044v1
1998-07-22,"Theory of Coexisting Charge and Spin-Density Waves in (TMTTF)_2Br, (TMTSF)_2PF_6 and alpha-(BEDT-TTF)_2MHg(SCN)_4","Recent experiments indicate that the spin-density waves (SDWs) in
(TMTTF)_2Br, (TMTSF)_2PF_6 and alpha-(BEDT-TTF)_2MHg(SCN)_4 are highly
unconventional and coexist with charge-density waves (CDWs). We present a
microscopic theory of this unusual CDW-SDW coexistence.
  A complete understanding requires the explicit inclusion of strong Coulomb
interactions, lattice discreteness, the anisotropic two-dimensional nature of
the lattice, and the correct bandfilling within the starting Hamiltonian.",9807308v1
2000-03-21,Stripe orders in the extended Hubbard model,"We study stripe orders of charge and spin density waves in the extended
Hubbard model with the nearest-neighbor Coulomb repulsion V within the mean
field approximation. We obtain V vs. T(temperature) phase diagram for the
on-site Coulomb interaction U/t=8.0 and the filling n=0.8, here t is a
nearest-neighbor transfer energy. Our result shows that the diagonal stripe
spin density wave state (SDW) is stable for small V, but for large V the most
stable state changes to a charge density wave-antiferromagnetic (CDW-AF) state.
Especially we find at low temperature and for a certain range of value of V, a
vertical stripe CDW-AF state becomes stable.",0003347v1
2000-03-27,Quarter-filled spin density wave states with long-range Coulomb interaction,"Spin density wave (SDW) states at quarter-filling, which coexist with charge
density wave (CDW) states, have been examined where the critical temperature is
calculated for an extended Hubbard model with long range repulsive
interactions. Within the mean-field theory, it is shown that the first order
transition occurs with decreasing temperature for interactions located around
the boundary between SDW state and CDW state.",0003422v2
2000-11-14,Odd-Frequency Density Waves: Non-Fermi-Liquid Metals with an Order Parameter,"We consider states with a charge- or spin-density wave order parameter which
is odd in frequency, so that the order parameter vanishes at zero frequency and
there is a conventional Fermi surface. Such states break translational symmetry
and, therefore, are not conventional Fermi liquids. In the odd-frequency
spin-density wave case, there are Goldstone bosons and the low-energy spectrum
is manifestly different from that of a Fermi liquid. We discuss a simple model
which gives rise to such ordered states. The frequency-dependence of the gap
leads to an unusual temperature dependence for various thermodynamic and
transport properties, notably the resistivity.",0011234v2
2001-09-04,Phase Diagram of One-Dimensional Extended Hubbard Model at Half Filling,"We reexamine the ground-state phase diagram of the one-dimensional
half-filled Hubbard model with on-site and nearest-neighbor repulsive
interactions. We calculate second-order corrections to coupling constants in
the g-ology to show that the bond-charge-density-wave (BCDW) phase exists for
weak couplings in between the charge density wave (CDW) and spin density wave
(SDW) phases. We find that the umklapp scattering of parallel-spin electrons
destabilizes the BCDW state and gives rise to a bicritical point where the
CDW-BCDW and SDW-BCDW continuous-transition lines merge into the CDW-SDW
first-order transition line.",0109051v1
2003-06-04,"Chiral Symmetry and Collective Excitations in p-wave, d-wave and f-wave Superconductors","We discuss the origin of charge density wave (CDW) and spin density wave
(SDW) in p-wave, d-wave and f-wave superconductors. To describe the low-energy
quasiparticle excitation of p-wave case, we introduce a two- (one for time and
one for space) dimensional massless Dirac model. After the non-Abelian
bosonization is performed, the charge and spin density waves emerge from the
model. By using this scheme, we try to explain the characteristic aspect of
phase diagrams of various compounds, oxides and organic superconductors. The
purpose of this paper is to make an argument that the dimensionality of the
nodal excitation in superconductors plays an important role in the
determination of the structure of the phase diagram.",0306095v1
2006-05-13,Scattering wave function approach to multi-terminal mesoscopic system with spin-orbit coupling,"In this paper,we present a detailed formulation to solve the scattering wave
function for a multi-terminal mesoscopic system with spin-orbit coupling. In
addition to terminal currents, all local quantities can be calculated
explicitly by taking proper ensemble average in the Landauer-Buttiker's spirit
using the scattering wave functions. Based on this formulation, we derive some
rigorous results for equilibrium state. Furthermore, some new symmetry
relations are found for the typical two terminal structure in which a
semiconductor bar with Rashba or/and Dresselhaus SO coupling is sandwiched
symmetrically between two leads. These symmetry property can provide accuracy
tests for experimental measurements and numerical calculations.",0605361v1
2004-11-17,Integral equations for the spin-weighted spheroidal wave function,"Integral equations for the spin-weighted spheroidal wave functions is given.
For the prolate spheroidal wave function with m=0, there exists the integral
equation whose kernel is(sin x)/x, and the sinc function kernel (sin x)/x is of
great mathematical significance. In the paper, we also extend the similar sinc
function kernel (sin x)/x to the case m and s both are not zero, which
interestingly turn out as some kind of Hankel transformation.",0411087v2
2000-12-13,An Attack to Quantum Cryptography from Space,"The promise of secure cryptographic quantum key distribution schemes is based
on the use of quantum effects in the spin space. We point out that in fact in
many current quantum cryptography protocols the space part of the wave function
is neglected. However exactly the space part of the wave function describes the
behaviour of particles in ordinary real three-dimensional space. As a result
such schemes can be secure against eavesdropping attacks in the abstract spin
space but could be insecure in the real three-dimensional space. We discuss an
approach to the security of quantum key distribution in space by using Bell's
inequality and a special preparation of the space part of the wave function.",0012054v1
2007-07-12,Properties of high-T$_C$ copper oxides from the nearly-free electron model,"The generic band structure of high-T$_C$ copper oxides is simulated by the
nearly free-electron model (NFE) in two dimensions (2-D) with parameters from
band calculations. Interaction between phonons and spin waves will cause
potential modulations and pseudogaps, and the strength of the modulations, the
wave lengths and the doping, are all related. A Fermi-surface ""arc"" is found
for dynamic spin/phonon waves. The confinement of superconductivity between two
limiting dopings can be a result of competition with the pseudogap at low
doping and weak coupling at high doping.",0707.1804v1
2007-07-16,Angular Momentum Imparted To Test Particles by Gravitational Waves,"What are gravitational waves? How do they propagate? and what is their energy
content? These questions are addressed in the first two chapters. In the third
chapter the pseudo-Newtonian formalism and its extension is reviewed in general
and the formula for the momentum imparted to test particles in arbitrary
spacetimes is reviewed in particular. In chapter four the analysis of a paper
claiming to determine the spin for gravitational waves is given, and compared
with the spin given by a geodesic analysis. It is demonstrated that the other
claim is inconsistent. Finally in chapter five a summary of the work is given
with the conclusion.",0707.2318v1
2007-12-03,Bright and dark solitary waves in a one-dimensional spin-polarized gas of fermionic atoms with p-wave interactions in a hard-wall trap,"In this paper we elucidate the physics underlying the fact that both bright
and dark solitary waves can arise in a one-dimensional spin-polarized gas of
fermionic atoms with attractive three-dimensional p-wave interactions in a
hard-wall trap. This is possible since the one-dimensional fermion system can
be mapped to a system of bosons described by the Lieb-Liniger model with either
repulsive or attractive delta-function interactions which can support solitary
waves.",0712.0355v1
2009-07-07,Multiband Superconductivity in Spin Density Wave Metals,"We study the emergence of multiband superconductivity with $s$- and $d-$wave
symmetry on the background of spin density wave (SDW). We show that the SDW
coherence factors renormalize the momentum dependence of the superconducting
(SC) gap, yielding a SC state with an \emph{unconventional} s-wave symmetry.
Interband Cooper pair scattering stabilizes superconductivity in both
symmetries. With increasing SDW order, the s-wave state is more strongly
suppressed than the d-wave state. Our results are universally applicable to
two-dimensional systems with a commensurate SDW.",0907.1296v1
2010-02-03,Massless and Massive Gauge-Invariant Fields in the Theory of Relativistic Wave Equations,"In this work consideration is given to massless and massive gauge-invariant
spin 0 and spin 1 fields (particles) within the scope of a theory of the
generalized relativistic wave equations with an extended set of the Lorentz
group representations. The results obtained may be useful as regards the
application of a relativistic wave-equation theory in modern field models.",1002.0720v1
2012-04-24,"Magnetostatic Spin Waves and Magnetic-Wave Chaos in Ferromagnetic Films. III. Numeric Simulations of Microwave-Band Magnetic Chaos, Its Synchronization and Application to Secure Communication","Selected results of original numeric simulations of non-linear magnetostatic
spin waves and microwave-frequency magnetic chaos in ferrite films are
expounded, as third part of the work whose first two parts are recent arXive
preprints 1204.0200 and 1204.2423 . Especially we consider crucial role of
parametric processes in creating the chaos and simultaneously obstacles to its
synchronization, and examine some possibilities of good enough synchronization
(to an extent allowing its use for direct secure communication in microwave
band).",1204.5410v1
2013-04-09,Instability of Walker Propagating Domain Wall in Magnetic Nanowires,"Stability of the well-known Walker propagating domain wall (DW) solution of
the Landau-Lifshitz-Gilbert equation is analytically investigated.
Surprisingly, the Walker's rigid body propagating DW mode is not stable against
the spin wave/wavepacket emission. In the low field region only stern spin
waves are emitted while both stern and bow waves are generated under high
fields. In a high enough field, but below the Walker breakdown field, the
Walker solution could be convective/absolute unstable if the transverse
magnetic anisotropy is larger than a critical value, corresponding to a
significant modification of the DW profile and DW propagating speed.",1304.2439v1
2014-11-19,Spin waves scattering on a Bloch point,"We show that, after a transformation, the dynamics of linear perturbations
(spin waves) around a singular Bloch point soliton is formally equivalent to a
quantum system of an electron in a magnetic monopole field. The analytical
solution to this problem is known and allows us to find the spectrum and the
scattering of a wave in a Bloch point field.",1411.5096v1
2014-12-18,Coherent elastic excitation of spin waves,"We model the injection of elastic waves into a ferromagnetic film (F) by a
non-magnetic transducer (N). We compare the configurations in which the
magnetization is normal and parallel to the wave propagation. The lack of axial
symmetry in the former results in the emergence of evanescent interface states.
We compute the energy-flux transmission across the N$|$F interface and
sound-induced magnetization dynamics in the ferromagnet. We predict efficient
acoustically induced pumping of spin current into a metal contact attached to
F.",1412.5820v2
2015-10-29,Spontaneous symmetry breaking in correlated wave functions,"We show that Jastrow-Slater wave functions, in which a density-density
Jastrow factor is applied onto an uncorrelated fermionic state, may possess
long-range order even when all symmetries are preserved in the wave function.
This fact is mainly related to the presence of a sufficiently strong Jastrow
term (also including the case of full Gutzwiller projection, suitable for
describing spin models). Selected examples are reported, including the spawning
of N\'eel order and dimerization in spin systems, and the stabilization of
charge and orbital order in itinerant electronic systems.",1510.08653v2
2016-01-31,Application of the Mössbauer spectroscopy to study harmonically modulated electronic structures: case study of charge- and spin-density waves in Cr and its alloys,"Relevance of the M\""ossbauer spectroscopy in the study of harmonically
modulated electronic structures i.e. spin-density waves (SDWs) and
charge-density waves (CDWs) is presented and discussed. First, the effect of
various parameters pertinent to the SDWs and CDWs is outlined on simulated
119Sn spectra and distributions of the hyperfine field and the isomer shift.
Next, various examples of the 119Sn spectra measured on single-crystals and
polycrystalline samples of Cr and Cr-V are reviewed.",1602.00272v1
2018-01-09,Dirac particles in a gravitational shock wave,"Using the Newman-Penrose formalism we calculate the positive energy momentum
eigenstates of the Dirac equation for a plane polarized grav- itational wave
pulse. We then consider Dirac particles whose spins are polarized in each
orthonormal coordinate direction prior to the arrival of the gravitational wave
pulse, and determine how the spins are changed by the pulse after its
departure.",1801.02756v3
2014-06-12,Gyratonic pp-waves and their impulsive limit,"We investigate a class of gravitational pp-waves which represent the exterior
vacuum field of spinning particles moving with the speed of light. Such exact
spacetimes are described by the original Brinkmann form of the pp-wave metric
including the often neglected off-diagonal terms. We put emphasis on a clear
physical and geometrical interpretation of these off-diagonal metric
components. We explicitly analyze several new properties of these spacetimes
associated with the spinning character of the source, such as rotational
dragging of frames, geodesic deviation, impulsive limits and the corresponding
behavior of geodesics.",1406.3227v2
2004-05-27,Excitation of magnetostatic spin waves in ferromagnetic films,"The torque equation of nonlinear spin dynamics is considered in the
magnetostatic approximation. In this framework, exact expressions for
propagator of linear magnetostatic waves in ferromagnetic film between two
antennas and corresponding mutual impedance of the antennas are derived, under
conditions of uniform but arbitrarily oriented static magnetization and
arbitrary anisotropy. The results imply also full description of spectrum of
the waves.",0405640v1
2023-07-05,Lifshitz model in the presence of spin-orbit coupling,"Wave function of a localized state created by a short-range impurity in two
dimensions falls off with distance, r, from the impurity as r^{-1/2}exp(-r/a),
where ""a"" is the localization radius. With randomly positioned identical
impurities with low concentration, n<<a^{-2}, the level smears into a band due
to the overlap of the impurity wave functions. This is the essence of the
Lifshitz model. We demonstrate that, upon incorporation of the spin-orbit
coupling, the impurity wave functions acquire oscillating factors which,
subsequently, modify their overlap. As a result of such modification, the
density of states develops singularities at certain energies.",2307.01971v1
2023-10-26,Spontaneously sliding multipole spin density waves in cold atoms,"We report on the observation of spontaneously drifting coupled spin and
quadrupolar density waves in the ground state of laser driven Rubidium atoms.
These laser-cooled atomic ensembles exhibit spontaneous magnetism via light
mediated interactions when submitted to optical feedback by a retro-reflecting
mirror. Drift direction and chirality of the waves arise from spontaneous
symmetry breaking. The observations demonstrate a novel transport process in
out-of-equilibrium magnetic systems.",2310.17305v2
2024-01-16,Wave packet treatment of neutrino flavour and spin oscillations in galactic and extragalactic magnetic fields,"We consider neutrino flavour and spin oscillations in a magnetic field using
formalism of wave packets. Decoherence effects due to neutrino wave packets
separation are studied. The considered effects are especially important for
describing astrophysical neutrino oscillations, since they propagate on
kiloparsec scale and bigger. The obtained results are of interest for neutrino
telescopes IceCube, Baikal-GVD and KM3NeT, and also can be applied for
description of supernovae neutrino oscillations effects would be detected by
JUNO and Hyper-Kamiokande.",2401.08724v2
2013-03-01,Generation of Electrostatic Waves via Parametric Instability and Heating of Solar Corona,"In the upper layers of the solar atmosphere the temperature increases
sharply. We studied possibility of the transfer of neutrals motion energy into
the electrostatic waves.Electrostatic waves could damp in the upper layers of
the solar atmosphere and their energy could be transformed into the thermal
energy of the solar atmosphere plasma. When studying the plasma dynamics in the
low altitudes of the solar atmosphere, we investigated hydrodynamics of the
plasma which consists of thee components-electrons, ions and neutrals. In order
to study evolution of disturbances of high amplitudes the parametric resonance
technique is used. The dispersion relation for the electrostatic waves excited
due tot he motion of neutrals is derived. The frequencies of electromagnetic
waves which could be excited due to existence of the acoustic wave are found.
The increment of excited electrostatic waves are determined. The motion of the
neutrals in the lower solar atmosphere, where ionization rate is low, could
excite electrostatic waves. In the upper solar atmosphere the ionization rate
increases and motion of the neutrals could not support electrostatic waves and
these waves could damp due to the collision of the charged particles. The
energy of the damping waves could be transformed into the thermal energy of the
plasma in the upper atmosphere.",1303.0151v1
2018-05-31,Bending Waves in the Milky Way's disc from halo substructure,"We use $N$-body simulations to investigate the excitation of bending waves in
a Milky Way-like disc-bulge-halo system. The dark matter halo consists of a
smooth component and a population of subhaloes while the disc is composed of
thin and thick components. Also considered is a control simulation where all of
the halo mass is smoothly distributed. We find that bending waves are more
vigorously excited in the thin disc than the thick one and that they are
strongest in the outer regions of the disc, especially at late times. By way of
a Fourier decomposition, we find that the complicated pattern of bending across
the disc can be described as a superposition of waves, which concentrate along
two branches in the radius-rotational frequency plane. These branches
correspond to vertical resonance curves as predicted by a WKB analysis. Bending
waves in the simulation with substructure have a higher amplitude than those in
the smooth-halo simulation, though the frequency-radius characteristics of the
waves in the two simulations are very similar. A cross correlation analysis of
vertical displacement and bulk vertical velocity suggests that the waves
oscillate largely as simple plane waves. We suggest that the wave-like features
in astrometric surveys such as the Second Data Release from \textit{Gaia} may
be due to long-lived waves of a dynamically active disc rather than, or in
addition to, perturbations from a recent satellite-disc encounter.",1805.12449v2
2020-11-20,Whistler Waves in the foot of Quasi-Perpendicular Super-Critical Shocks,"Whistler waves are thought to play an essential role in the dynamics of
collisionless shocks. We use the magnetospheric multiscale (MMS) spacecraft to
study whistler waves around the lower hybrid frequency, upstream of 11
quasi-perpendicular super-critical shocks. We apply the 4-spacecraft timing
method to unambiguously determine the wave vector $\mathbf{k}$ of whistler
waves. We find that the waves are oblique to the background magnetic field with
a wave-normal angle between $20^{\circ}$ and $42^{\circ}$, a wavelength around
100 km which is close to the ion inertial length. We also find that
$\mathbf{k}$ is predominantly in the same plane as the magnetic field and the
normal to the shock. By combining this precise knowledge of $\mathbf{k}$ with
high-resolution measurements of the 3D ion velocity distribution we show that a
reflected ion beam is in resonance with the waves, opening up the possibility
for wave-particle interaction between the reflected ions and the observed
whistlers. The linear stability analysis of a system mimicking the observed
distribution, suggests that such a system can produce the observed waves.",2011.10593v4
2021-04-06,Modeling interactions of narrowband large amplitude whistler-mode waves with electrons in the solar wind inside ~.3 AU and at 1 AU using a particle tracing code,"The discovery of large-amplitude narrowband whistler-mode waves at
frequencies of tenths of the electron cyclotron frequency in large numbers both
inside ~.3 AU and at ~1 AU provides an answer to longstanding questions about
scattering and energization of solar wind electrons. The waves can have rapid
nonlinear interactions with electrons over a broad energy range.
Counter-propagation between electrons and waves is not required for resonance
with the obliquely propagating waves in contrast to the case for parallel
propagation. Using a full 3d particle tracing code, we have examined
interactions of electrons with energies from 0 eV to 2 keV with whistler-mode
waves with amplitudes of 20 mV/m and propagation angles from 0 to 180 degrees
to the background magnetic field. Interactions with wave packets and single
waves are both modeled based on observations at ~.3 AU and 1 AU. The
simulations demonstrate the key role played by these waves in rapid scattering
and energization of electrons. Results provide evidence for nonlinear effects,
indicating that quasi-linear methods are not adequate for modeling the role of
whistlers in the evolution of solar wind electrons. Strong scattering and
energization for some initial energy and pitch angle ranges occurs for both
counter-propagating and obliquely propagating waves. The strong scattering of
strahl electrons counteracts the pitch angle narrowing due to conservation of
the first adiabatic invariant as electrons propagate away from the sun into
regions of smaller magnetic field. Scattering also produces the hotter
isotropic halo. The concomitant limiting of the electron heat flux is also
relevant in other astrophysical settings.",2104.02824v1
2022-11-10,Intense whistler-mode waves at foreshock transients: characteristics and regimes of wave-particle resonant interaction,"Thermalization and heating of plasma flows at shocks result in unstable
charged-particle distributions which generate a wide range of electromagnetic
waves. These waves, in turn, can further accelerate and scatter energetic
particles. Thus, the properties of the waves and their implication for
wave-particle interactions are critically important for modeling energetic
particle dynamics in shock environments. Whistler-mode waves, excited by the
electron heat flux or a temperature anisotropy, arise naturally near shocks and
foreshock transients. As a result, they can often interact with supra-thermal
electrons. The low background magnetic field typical at the core of such
transients and the large wave amplitudes may cause such interactions to enter
the nonlinear regime. In this study, we present a statistical characterization
of whistler-mode waves at foreshock transients around Earth bow shock, as they
are observed under a wide range of upstream conditions. We find that a
significant portion of them are sufficiently intense and coherent to warrant
nonlinear treatment. Copious observations of background magnetic field
gradients and intense whistler wave amplitudes suggest that phase trapping, a
very effective mechanism for electron acceleration in inhomogeneous plasmas,
may be the cause. We discuss the implications of our findings for electron
acceleration in planetary and astrophysical shock environments.",2211.05398v1
2023-03-17,Nonlinear dynamics of small-scale Alfvén waves,"We study the nonlinear evolution of very oblique small-scale Alfv\'en waves
with $k_\perp d_i\gtrsim 1$. At these scales, the waves become significantly
compressive, unlike in MHD, due to the Hall term in the equations. We
demonstrate that when frequencies are small compared to the ion gyrofrequency
and amplitudes small compared to unity, no new nonlinear interaction appears
due to the Hall term alone at the lowest non-trivial order, even when $k_\perp
d_i \sim 1$. However, at the second non-trivial order, we discover that the
Hall physics leads to a slow but resonant nonlinear interaction between
co-propagating Alfv\'en waves, an inherently 3D effect. Including the effects
of finite temperature, finite frequency, and electron inertia, the two-fluid
Alfv\'en wave also becomes dispersive once one or more of $k_\perp \rho_s$,
$k_\perp d_e$, or $k_\parallel d_i$ becomes significant: for oblique waves at
low $\beta$ as studied here, this can be at a much smaller scale than $d_i$. We
show that the timescale for one-dimensional steepening of two-fluid Alfven
waves is only significant at these smaller dispersive scales, and also derive
an expression for the amplitude of driven harmonics of a primary wave.
Importantly, both new effects are absent in gyrokinetics and other commonly
used reduced two-fluid models. Our calculations have relevance for the
interpretation of laboratory Alfv\'en wave experiments, as well as shedding
light on the physics of turbulence in the solar corona and inner solar wind,
where the dominant nonlinear interaction between counter-propagating waves is
suppressed, allowing these new effects to become important.",2303.10192v1
2004-05-28,Hyperfine interaction in a quantum dot: Non-Markovian electron spin dynamics,"We have performed a systematic calculation for the non-Markovian dynamics of
a localized electron spin interacting with an environment of nuclear spins via
the Fermi contact hyperfine interaction. This work applies to an electron in
the s -type orbital ground state of a quantum dot or bound to a donor impurity,
and is valid for arbitrary polarization p of the nuclear spin system, and
arbitrary nuclear spin I in high magnetic fields. In the limit of p=1 and
I=1/2, the Born approximation of our perturbative theory recovers the exact
electron spin dynamics. We have found the form of the generalized master
equation (GME) for the longitudinal and transverse components of the electron
spin to all orders in the electron spin--nuclear spin flip-flop terms. Our
perturbative expansion is regular, unlike standard time-dependent perturbation
theory, and can be carried-out to higher orders. We show this explicitly with a
fourth-order calculation of the longitudinal spin dynamics. In zero magnetic
field, the fraction of the electron spin that decays is bounded by the
smallness parameter \delta=1/p^{2}N, where N is the number of nuclear spins
within the extent of the electron wave function. However, the form of the decay
can only be determined in a high magnetic field, much larger than the maximum
Overhauser field. In general the electron spin shows rich dynamics, described
by a sum of contributions with non-exponential decay, exponential decay, and
undamped oscillations. There is an abrupt crossover in the electron spin
asymptotics at a critical dimensionality and shape of the electron envelope
wave function. We propose a scheme that could be used to measure the
non-Markovian dynamics using a standard spin-echo technique, even when the
fraction that undergoes non-Markovian dynamics is small.",0405676v2
1995-08-16,Stochastic Particle Acceleration near Accreting Black Holes,"We consider the stochastic acceleration of particles which results from
resonant interactions with plasma waves in black hole magnetospheres. We
calculate acceleration rates and escape time scales for protons and electrons
resonating with Alfv\'en waves, and for electrons resonating with whistlers.
Assuming either a Kolmogorov or Kraichnan wave spectrum, accretion at the
Eddington limit, magnetic field strengths near equipartition, and turbulence
energy densities $\sim 10\%$ of the total magnetic field energy density, we
find that Alfv\'en waves accelerate protons to Lorentz factors $\lte
10^4$--$10^6$ before they escape from the system. Acceleration of electrons by
fast mode and whistler waves can produce a nonthermal population of
relativistic electons whose maximum energy is determined by a competition with
radiation losses. Particle energization and outflow is not possible at lower
accretion rates, magnetic field strengths, or turbulence levels due to dominant
Coulomb losses. Increases in the accretion luminosity relative to the Eddington
luminosity can trigger particle acceleration out of the thermal background, and
this mechanism could account for the differences between radio-quiet and
radio-loud active galactic nuclei. Observations of outflowing radio-emitting
components following transient X-ray events in galactic X-ray novae and
gamma-ray flares in blazars are in accord with this scenario.",9508069v1
2005-11-01,Disk heating by more than one spiral density wave,"We consider a differentially rotating, 2D stellar disk perturbed by two
steady state spiral density waves moving at different patterns speeds. Our
investigation is based on direct numerical integration of initially circular
test-particle orbits. We examine a range of spiral strengths and spiral speeds
and show that stars in this time dependent gravitational field can be heated
(their random motions increased).This is particularly noticeable in the
simultaneous propagation of a 2-armed spiral density wave near the corotation
resonance (CR), and a weak 4-armed one near the inner and outer 4:1 Lindblad
resonances. In simulations with 2 spiral waves moving at different pattern
speeds we find: (1) the variance of the radial velocity, sigma_R^2, exceeds the
sum of the variances measured from simulations with each individual pattern;
(2) sigma_R^2 can grow with time throughout the entire simulation; (3)
sigma_R^2 is increased over a wider range of radii compared to that seen with
one spiral pattern; (4) particles diffuse radially in real space whereas they
don't when only one spiral density wave is present. Near the CR with the
stronger, 2-armed pattern, test particles are observed to migrate radially.
These effects take place at or near resonances of both spirals so we interpret
them as the result of stochastic motions. This provides a possible new
mechanism for increasing the stellar velocity dispersion in galactic disks. If
multiple spiral patterns are present in the Galaxy we predict that there should
be large variations in the stellar velocity dispersion as a function of radius.",0511037v1
2006-04-09,Three-dimensional strong localization of matter waves by scattering from atoms in a lattice with a confinement-induced resonance,"The possibility of using ultracold atoms to observe strong localization of
matter waves is now the subject of a great interest, as undesirable decoherence
and interactions can be made negligible in these systems. It was proposed that
a static disordered potential can be realized by trapping atoms of a given
species in randomly chosen sites of a deep 3D optical lattice with no multiple
occupation. We analyze in detail the prospects of this scheme for observing
localized states in 3D for a matter wave of a different atomic species that
interacts with the trapped particles and that is sufficiently far detuned from
the optical lattice to be insensitive to it. We demonstrate that at low energy
a large number of 3D strongly localized states can be produced for the matter
wave, if the effective scattering length describing the interaction of the
matter wave with a trapped atom is of the order of the mean distance between
the trapped particles. Such high values of the effective scattering length can
be obtained by using a Feshbach resonance to adjust the free space
inter-species scattering length and by taking advantage of confinement-induced
resonances induced by the trapping of the scatterers in the lattice.",0604232v2
2005-10-28,Radial disk heating by more than one spiral density wave,"We consider a differentially rotating, 2D stellar disk perturbed by two
steady state spiral density waves moving at different patterns speeds. Our
investigation is based on direct numerical integration of initially circular
test-particle orbits. We examine a range of spiral strengths and spiral speeds
and show that stars in this time dependent gravitational field can be heated
(their random motions increased). This is particularly noticeable in the
simultaneous propagation of a 2-armed spiral density wave near the corotation
resonance (CR), and a weak 4-armed one near the inner and outer 4:1 Lindblad
resonances. In simulations with 2 spiral waves moving at different pattern
speeds we find: (1) the variance of the radial velocity, sigma_R^2, exceeds the
sum of the variances measured from simulations with each individual pattern;
(2) sigma_R^2 can grow with time throughout the entire simulation; (3)
sigma_R^2 is increased over a wider range of radii compared to that seen with
one spiral pattern; (4) particles diffuse radially in real space whereas they
don't when only one spiral density wave is present. Near the CR with the
stronger, 2-armed pattern, test particles are observed to migrate radially.
These effects take place at or near resonances of both spirals so we interpret
them as the result of stochastic motions. This provides a possible new
mechanism for increasing the stellar velocity dispersion in galactic disks. If
multiple spiral patterns are present in the Galaxy we predict that there should
be large variations in the stellar velocity dispersion as a function of radius.",0510074v1
2009-09-27,Space-time symmetry violation of the fields in quasi-2D ferrite particles with magnetic-dipolar-mode oscillations,"In magnetic systems with reduced dimensionality, the effects of dipolar
interactions allow the existence of long-range ordered phases. Long-range
magnetic-dipolar interactions are at the heart of the explanation of many
peculiar phenomena observed in nuclear magnetic resonance, ferromagnetic
resonance, and Bose-Einstein-condensate structures. In this paper we show that
magnetic-dipolar-modes (MDMs) in quasi-2D ferrite disks are characterized by
symmetry breaking effects. Our analysis is based on postulates about a physical
meaning of the magnetostatic-potential function as a complex scalar wave
function, which presumes the long-range phase correlations. An important
feature of the MDM oscillations in a ferrite disk concerns the fact that a
structure with symmetric parameters and symmetric basic equations goes into
eigenstates that are not space-time symmetric. The proper solutions are found
based on an analysis of magnetostatic-wave propagation in a helical coordinate
system. For a ferrite disk, we show that while a composition of two helical
waves may acquire a geometrical phase over-running of during a period, every
separate helical wave has a dynamical phase over-running of and so behaves as a
double-valued function. We demonstrate that unique topological structures of
the fields in a ferrite disk are intimately related to the symmetry breaking
properties of MDM oscillations. The solutions give the MDM power-flow-density
vortices with cores at the disk center and azimuthally running waves of
magnetization. One can expect that the proposed models of long-range ordered
phases and space-time violation properties of magnetic-dipolar interactions can
be used in other magnetic structures, different from the
ferromagnetic-resonance system with reduced dimensionality.",0909.4920v1
2015-06-30,Resonant Absorption of Transverse Oscillations and Associated Heating in a Solar Prominence. I- Observational aspects,"Transverse magnetohydrodynamic (MHD) waves have been shown to be ubiquitous
in the solar atmosphere and can in principle carry sufficient energy to
generate and maintain the Sun's million-degree outer atmosphere or corona.
However, direct evidence of the dissipation process of these waves and
subsequent heating has not yet been directly observed. Here we report on high
spatial, temporal, and spectral resolution observations of a solar prominence
that show a compelling signature of so-called resonant absorption, a long
hypothesized mechanism to efficiently convert and dissipate transverse wave
energy into heat. Aside from coherence in the transverse direction, our
observations show telltale phase differences around 180 degrees between
transverse motions in the plane-of-sky and line-of-sight velocities of the
oscillating fine structures or threads, and also suggest significant heating
from chromospheric to higher temperatures. Comparison with advanced numerical
simulations support a scenario in which transverse oscillations trigger a
Kelvin-Helmholtz instability (KHI) at the boundaries of oscillating threads via
resonant absorption. This instability leads to numerous thin current sheets in
which wave energy is dissipated and plasma is heated. Our results provide
direct evidence for wave-related heating in action, one of the candidate
coronal heating mechanisms.",1506.08965v1
2017-11-01,Realization of a Contactless Acoustic Levitation Motor via Doublet Mode Control and Autoresonance,"This paper demonstrates analytically and experimentally an acoustic
levitation motor which has the ability to levitate and rotate an object in the
air without mechanical contact. To realize such a device two core methods are
applied simultaneously; (i) resonance tracking with an Autoresonance feedback
loop, (ii) generation of controlled structural traveling waves. The purpose of
the first method is to achieve near-field acoustic levitation, which can
levitate an object of a few kilograms. In this research, this is accomplished
through high amplitude vibration of an aluminum annulus at ultrasonic
frequencies (~30kHz). For high efficiency, the annulus is designed to have a
very high Q value, and operating even slightly off resonance ceases levitation.
Compounding this is the fact that the natural frequency constantly drifts as
ambient conditions and loading change. To accommodate such a drift, and produce
stable levitation automatically, a resonance tracking feedback loop is employed
here. Simultaneously, the purpose of the second method is to achieve propulsion
forces on the levitated object by propagating and controlling traveling waves
in the aluminum annulus to create a thin layer of rotating air beneath the
levitated body. Even though a single vibration mode can produce only standing
waves, an axisymmetric structure possesses two modes per natural frequency, and
excitation of a doublet mode pair can generate effective travelling waves. The
present paper develops the theory behind the use of the Autoresonance feedback
method for achieving constant levitation and propagating travelling waves in
co- and counter rotating directions. It will be shown that all this can be
accomplished with only single sensor. The result is a stable, repeatable and a
highly controllable contactless acoustic levitation motor.",1711.00380v1
2018-03-29,The linear theory of tidally excited spiral density waves: application to CV and circumplanetary disks,"We revisit linear tidal excitation of spiral density waves in the disks of
cataclysmic variables (CVs), focusing on scalings with orbital Mach number in
order to bridge the gap between numerical simulations and real systems. If an
inner Lindblad resonance (ILR) lies within the disk, ingoing waves are robustly
excited, and the angular-momentum flux they carry is independent of Mach
number. But in most CVs, the ILR lies outside the disk. The wave flux and its
scaling with Mach number are then very sensitive to conditions near the disk
edge. If the temperature and sound speed vanish there, excitation tends to be
exponentially suppressed. If the Mach number remains finite in the outer parts
but the radial and vertical density scale lengths become comparable due to
subkeplerian rotation, resonance can occur with acoustic-cutoff and
stratification frequencies. These previously neglected resonances excite waves,
but the Mach-number scaling remains very steep if the radial scale length
decreases gradually. The scaling can be less strong - algebraic rather than
exponential - if there are sharp changes in surface density at finite sound
speed. Shocks excited by streamline-crossing or by the impact of the stream
from the companion are unlikely to be important for the angular-momentum
budget, at least in quiescence. Our results may also apply to circumplanetary
disks, where Mach numbers are likely lower than in CVs.",1803.10921v1
2019-11-01,Free and forced wave propagation in beam lattice metamaterials with viscoelastic resonators,"Beam lattice materials are characterized by a periodic microstructure
realizing a geometrically regular pattern of elementary cells. In these
microstructured materials, the dispersion properties governing the free dynamic
propagation of elastic waves can be studied by formulating parametric
lagrangian models and applying the Floquet-Bloch theory. Within this framework,
governing the wave propagation by means of spectral design techniques and/or
energy dissipation mechanisms is a major issue of theoretical and applied
interest. Specifically, the wave propagation can be inhibited by purposely
designing the microstructural parameters to open band gaps in the material
spectrum at target center frequencies. Based on these motivations, a general
dynamic formulation for determining the dispersion properties of beam lattice
metamaterials, equipped with local resonators is presented. The mechanism of
local resonance is realized by tuning periodic auxiliary masses,
viscoelastically coupled with the beam lattice microstructure. As peculiar
aspect, the viscoelastic coupling is derived by a mechanical formulation based
on the Boltzmann superposition integral, whose kernel is approximated by a
Prony series. Consequently, the free propagation of damped waves is governed by
a linear homogeneous system of integral-differential equations of motion.
Therefore, differential equations of motion with frequency-dependent
coefficients are obtained by applying the bilateral Laplace transform. The
corresponding complex-valued branches characterizing the dispersion spectrum
are determined and parametrically analyzed. Particularly, the spectra
corresponding to Taylor series approximations of the equation coefficients are
investigated.",1911.00455v1
2018-08-14,Wave propagation in infinite nonlinear acoustic metamaterial beam by considering the third harmonic generation,"Nonlinear acoustic metamaterial (NAM) initiates new fields for controlling
elastic waves. In this work, the flexural wave propagation in the half-infinite
NAM beam consisting of periodic Duffing resonators is reported by considering
the third harmonic generation (THG). Different analytical methods are proposed
to describe the wave propagation in the equivalent homogenous medium. Then
their effectiveness and accuracy are demonstrated in comparison with the finite
element methods. We unveil analytically and numerically extensive physical
properties of the strongly nonlinear AM, including the nonlinear resonance in a
cell, the effective density, nonlinear locally resonant (NLR) bandgap,
propagations and couplings of the fundamental and the third harmonics. These
characteristics are highly interrelated, which facilitates the prediction of
functionalities. In the near field, the identical bifurcation frequency of
these features acts as the start frequency of the NLR bandgap for fundamental
waves, whose width is narrower for a stronger nonlinearity. While in the far
field, the NLR bandgap characterizes a distance-amplitude-dependent behavior
leading to a self-adaptive bandwidth. Moreover, the transmission in the
passband of the infinite NAM is different from the chaotic band effect of
finite NAMs, and it is influenced by the shifted NLR gap. Our work will promote
future studies and constructions of NAMs with novel properties.",1808.04682v2
2017-06-15,Resonant drag instability of grains streaming in fluids,"We show that grains streaming through a fluid are generically unstable if
their velocity, projected along some direction, matches the phase velocity of a
fluid wave (linear oscillation). This can occur whenever grains stream faster
than any fluid wave. The wave itself can be quite general--sound waves,
magnetosonic waves, epicyclic oscillations, and Brunt-V\""ais\""al\""a
oscillations each generate instabilities, for example. We derive a simple
expression for the growth rates of these ""resonant drag instabilities"" (RDI).
This expression (i) illustrates why such instabilities are so virulent and
generic, and (ii) allows for simple analytic computation of RDI growth rates
and properties for different fluids. As examples, we introduce several new
instabilities, which could see application across a variety of physical systems
from atmospheres to protoplanetary disks, the interstellar medium, and galactic
outflows. The matrix-based resonance formalism we introduce can also be applied
more generally in other (nonfluid) contexts, providing a simple means for
calculating and understanding the stability properties of interacting systems.",1706.05020v5
2017-10-25,Electromagnetic waves propagating in the string axiverse,"It is widely believed that axions are ubiquitous in string theory and could
be the dark matter. The peculiar features of the axion dark matter are coherent
oscillations and a coupling to the electromagnetic field through the
Chern-Simons term. In this paper, we study consequences of these two features
of the axion with the mass in a range from $10^{-13}\,{\rm eV}$ to
$10^{3}\,{\rm eV}$. First, we study the parametric resonance of electromagnetic
waves induced by the coherent oscillation of the axion. As a result of the
resonance, the amplitude of the electromagnetic waves is enhanced and the
circularly polarized monochromatic waves will be generated. Second, we study
the velocity of light in the background of the axion dark matter. In the
presence of the Chern-Simons term, the dispersion relation is modified and the
speed of light will oscillate in time. It turns out that the change of speed of
light would be difficult to observe. We argue that the future radio wave
observations of the resonance can give rise to a stronger constraint on the
coupling constant and/or the density of the axion dark matter.",1710.09198v2
2017-03-21,"Two-body Wave Functions, Compositeness, And The Internal Structure Of Dynamically Generated Resonances","Recently, the compositeness, defined as the norm of a two-body wave function
for bound and resonance states, has been investigated to discuss the internal
structure of hadrons in terms of hadronic molecular components. From the
studies of the compositeness, it has been clarified that the two-body wave
function of a bound state can be extracted from the residue of the scattering
amplitude at the bound state pole. Of special interest is that the two-body
wave function from the scattering amplitude is automatically normalized. In
particular, while the compositeness is unity for energy-independent
interactions, it deviates from unity for energy-dependent interactions, which
can be interpreted as a missing-channel contribution. In this manuscript, we
show the formulation of the two-body wave function from the scattering
amplitude, evaluate the compositeness for several dynamically generated
resonances such as $f_{0} (980)$, $\Lambda (1405)$, and $\Xi (1690)$, and
investigate their internal structure in terms of the hadronic molecular
components.",1703.07176v1
2019-04-10,The role of resonance and bandgaps in high $k_\textrm{eff}^2$ transducers,"Bandgaps formed in a piezoelectric transducer with large coupling,
$k_\textrm{eff}^2$, qualitatively modify its electrical response. This regime
in which electrical loading strongly couples forward and backward waves occurs
in thin-film lithium niobate which has recently become available and amenable
to nanopatterning. In this work, we study how resonance and bandgaps modify the
design and performance of transducers and delay lines in thin-film lithium
niobate. These films are an attractive platform for GHz frequency applications
in low-power RF analog signal processing, optomechanics, and quantum devices
due to their high coupling, low loss, excellent optical properties, and
compatibility with superconducting quantum circuits. We demonstrate aluminum
IDTs in this platform for horizontal shear (SH) waves between $1.2$ and $3.3$
GHz and longitudinal waves between $2.1$ and $5.4$ GHz. For the SH waves, we
measure a piezoelectric coupling coefficient of $13\%$ and $6.0$ dB/mm
propagation losses in delay lines up to $1.2$ mm with a $300$ ns delay in air
at room temperature. Reflections from electrical loading when
$k_\textrm{eff}^2$ is large lead to a departure from the impulse response model
widely used to model surface acoustic wave devices. Finite element method
models and an experimental finger-pair sweep are used to characterize the role
of resonance in these transducers, illuminating the physics behind the
anomalously large motional admittances of these small-footprint IDTs.",1904.04981v1
2019-12-22,Scattering from compact objects: Regge poles and the complex angular momentum method,"We calculate the Regge poles of the scattering matrix for a gravitating
compact body, for scalar fields and for gravitational waves in the axial
sector. For a neutron-starlike body, the spectrum exhibits two distinct
branches of poles, labeled surface waves and broad resonances; for ultracompact
objects, the spectrum also includes a finite number of narrow resonances. We
show, via a WKB analysis, that the discontinuity of the effective potential at
the body's surface determines the imaginary component of the broad-resonance
poles. Next, we examine the role of Regge poles in the time-independent
scattering of monochromatic planar waves. We apply complex angular momentum
techniques to re-sum the partial wave series for the scattering amplitude,
expressing it as a residue series evaluated at poles in the first quadrant,
accompanied by a background integral. We compute the scattering cross section
at several frequencies, and show precise agreement with the partial-wave
calculations. Finally, we show that compact bodies naturally give rise to
orbiting, glory, and rainbow-scattering interference effects.",1912.11348v2
2022-01-09,Acoustics of a partially partitioned narrow slit connected to a half-plane: case study for exponential quasi-bound states in the continuum and their resonant excitation,"Localised wave oscillations in an open system that do not decay or grow in
time, despite their frequency lying within a continuous spectrum of radiation
modes carrying energy to or from infinity, are known as bound states in the
continuum (BIC). Small perturbations from the typically delicate conditions for
BIC almost always result in the waves weakly coupling with the radiation modes,
leading to leaky states called quasi-BIC that have a large quality factor. We
study the asymptotic nature of this weak coupling in the case of acoustic waves
interacting with a rigid substrate featuring a partially partitioned slit -- a
setup that supports quasi-BIC that exponentially approach BIC as the slit is
made increasingly narrow. In that limit, we use the method of matched
asymptotic expansions in conjunction with reciprocal relations to study those
quasi-BIC and their resonant excitation. In particular, we derive a leading
approximation for the exponentially small imaginary part of each wavenumber
eigenvalue (inversely proportional to quality factor), which is beyond all
orders of the expansion for the wavenumber eigenvalue itself. Furthermore, we
derive a leading approximation for the exponentially large amplitudes of the
states in the case where they are resonantly excited by a plane wave at oblique
incidence. These resonances occur in exponentially narrow wavenumber intervals
and are physically manifested in cylindrical-dipolar waves emanating from the
slit aperture and exponentially large field enhancements inside the slit. The
asymptotic approximations are validated against numerical calculations.",2201.03554v1
2023-07-14,A resonant Lyapunov centre theorem with an application to doubly periodic travelling hydroelastic waves,"We present a Lyapunov centre theorem for an antisymplectically reversible
Hamiltonian system exhibiting a nondegenerate $1:1$ or $1:-1$ semisimple
resonance as a detuning parameter is varied. The system can be finite- or
infinite dimensional (and quasilinear) and have a non-constant symplectic
structure. We allow the origin to be a ""trivial"" eigenvalue arising from a
translational symmetry or, in an infinite-dimensional setting, to lie in the
continuous spectrum of the linearised Hamiltonian vector field provided a
compatibility condition on its range is satisfied.
  As an application we show how Kirchg\""{a}ssner's spatial dynamics approach
can be used to construct doubly periodic travelling waves on the surface of a
three-dimensional body of water (of finite or infinite depth) beneath a thin
ice sheet (hydroelastic waves). The hydrodynamic problem is formulated as a
reversible Hamiltonian system in which an arbitrary horizontal spatial
direction is the time-like variable and the infinite-dimensional phase space
consists of wave profiles which are periodic (with fixed period) in a second,
different horizontal direction. Applying our Lyapunov centre theorem at a point
in parameter space associated with a $1:1$ or $1:-1$ semisimple resonance
yields a periodic solution of the spatial Hamiltonian system corresponding to a
doubly periodic hydroelastic wave.",2307.07194v1
2024-02-27,A computational method for angle-resolved photoemission spectra from repeated-slab band structure calculations,"A versatile method for angle-resolved photoemission spectra (ARPES)
calculations is reported within the one-step model of photoemission. The
initial states are obtained from a repeated-slab calculation using the
projector-augmented wave (PAW) method. ARPES final states are constructed by
matching the repeated-slab eigenstates of positive energy with free electron
states that satisfy the time-reversed low-energy electron diffraction boundary
conditions. Nonphysical solutions of the matching equations, which do not
respect the flux conservation, are discarded. The method is applied to
surface-normal photoemission from graphene as a function of photon energy from
threshold up to 100 eV. The results are compared with independently performed
multiple scattering calculations and very good agreement is obtained, provided
that the photoemission matrix elements are computed with all-electron waves
reconstructed from the PAW pseudo-waves. However, if the pseudo-waves are used
directly, the relative intensity between $\sigma$- and $\pi$-band emission is
wrong by an order of magnitude. The graphene ARPES intensity has a strong
photon energy dependence including resonances. The normal emission spectrum
from the $\pi$-band shows a hitherto unreported, sharp resonance at a photon
energy of 31 eV. The resonance is due to a 2$D$ interband transitions and
highlights the importance of matrix element effects beyond the final state
plane-wave approximation.",2402.17199v1
2004-12-29,An analytic study of the gravitational wave pulsar signal with spin down effects,"In this work, we present the analytic treatment of the Fourier Transform (FT)
of the Gravitational Wave (GW) signal from a pulsar including spin down
corrections in a parametrized model discussed by Brady et. al. The formalism
lends itself to a development of the FT in terms of well known special
functions and integrals defining the spin down moments.",0412646v1
1992-11-24,Possible Quantum Spin Liquid States on the Triangular and Kagome Lattices,"The frustrated spin-one-half Heisenberg model on triangualr and Kagome
Lattices is mapped onto a single specis of fermion carrying statistical flux.
The corresponding Chern-Simons gauge theory is analyzed at the Gaussian level
and found to be massive. This provides a new motivation for the spin-liquid
Kalmeyer-Laughlin wave function. Good overlap of this wave function with the
numerical ground state is found for small clusters.",9211017v1
1993-10-11,Half-Integral Spin-Singlet Quantum Hall Effect,"We provide numerical evidence that the ground state of a short range
interaction model at $\nu=1/2$ is incompressible and spin-singlet for a wide
range of repulsive interactions. Furthermore it is accurately described by a
trial wave function studied earlier. For the Coulomb interaction we find that
this wave function provides a good description of the lowest lying spin-singlet
state, and propose that fractional quantum Hall effect would occur at $\nu=1/2$
if this state became the global ground state.",9310020v1
1994-04-18,Intensity correlations in electronic wave propagation in a disordered medium: the influence of spin-orbit scattering,"We obtain explicit expressions for the correlation functions of transmission
and reflection coefficients of coherent electronic waves propagating through a
disordered quasi-one-dimensional medium with purely elastic diffusive
scattering in the presence of spin-orbit interactions. We find in the metallic
regime both large local intensity fluctuations and long-range correlations
which ultimately lead to universal conductance fluctuations. We show that the
main effect of spin-orbit scattering is to suppress both local and long-range
intensity fluctuations by a universal symmetry factor 4. We use a scattering
approach based on random transfer matrices.",9404054v1
1997-09-26,Scaling relation of spin wave lifetime in double-exchange systems,"Spin excitation spectrum of CMR manganites are studied from both theoretical
and experimental sides. Scaling relations for the spin wave lifetime in the
electronic model with double-exchange interaction is observed, which is
consistent with results for neutron inelastic scattering experiments for
(La,Y)$_{0.8}$Sr$_{0.2}$MnO$_3$. Roles of other interactions and degrees of
freedom such as polaron effects are also discussed.",9709294v1
1998-03-20,Transitions between Phases with Equal Wave Numbers in a Double Ising Spin Model. Application to Betaine Calcium Chloride Dihydrate,"A Double Ising Spin model for uniaxially structurally modulated materials
exhibits as a special feature phase transitions between phases with equal wave
numbers but different pseudo spin configurations. The character of these
`internal' transitions is investigated in mean field approximation, with the
mean field transfer matrix method, and in Monte Carlo simulations. The
structural changes at the transitions are characterized by different strengths
of harmonics in a Fourier analysis of the spatial modulation. A dielectric
anomaly in the phase diagram of betaine calcium chloride dihydrate (BCCD) and
seemingly contradictory structure analyses are explained.",9803252v1
1999-04-26,Magnon Damping by magnon-phonon coupling in Manganese Perovskites,"Inelastic neutron scattering was used to systematically investigate the
spin-wave excitations (magnons) in ferromagnetic manganese perovskites. In
spite of the large differences in the Curie temperatures ($T_C$s) of different
manganites, their low-temperature spin waves were found to have very similar
dispersions with the zone boundary magnon softening. From the wavevector
dependence of the magnon lifetime effects and its correlation with the
dispersions of the optical phonon modes, we argue that a strong magneto-elastic
coupling is responsible for the observed low temperature anomalous spin
dynamical behavior of the manganites.",9904372v1
1999-07-12,Quantum Hall Transitions in Field Induced Spin Density Wave Systems,"Field Induced Spin Density Wave (FISDW) systems exhibit coexistence phases
between well defined quantum Hall plateau phases with even integers 2N and 2N'.
We show that a disordered coexistence region accounts for the observed peaks in
the longitudinal resistivity as the field varies between plateaux. It also
results in a random spin mixing which yields two energy split extended states.
The longitudinal resistance is expected to show peaks witha temperature (T)
dependent width proportional to the kappa's power of T. The peak width should
saturate below the non-nesting interlayer coupling of order 40 mK",9907170v1
1999-07-19,Spin waves in a two dimensional p-wave superconductor: Sr$_2$RuO$_4$,"We study spin excitations in a two dimensional p-wave superconductor with
${\vec \Delta} = {\hat d}({\hat k}_1 \pm i {\hat k}_2)$ symmetry in the context
of the newly discovered superconducting Sr$_2$RuO$_4$. The polarization and
spectrum of spin wave excitations are identified and their experimental
consequences are discussed.",9907276v2
2001-05-31,Phase transition and spin-wave dispersion in quantum Hall bilayers at filling factor nu=1,"We present an effective Hamiltonian for a bilayer quantum Hall system at
filling factor $\nu=1$ neglecting charge fluctuations. Our model is formulated
in terms of spin and pseudospin operators and is an exact representation of the
system within the above approximation. We analyze its low-lying excitations in
terms of spin-wave theory. Moreover we add to previous first-principle
exact-diagonalization studies concentrating on the quantum phase transition
seen in this system.",0105625v2
2001-08-24,Influence of disorder on the ferromagnetism in diluted magnetic semiconductors,"Influence of disorder on the ferromagnetic phase transition in diluted
(III,Mn)V semiconductors is investigated analytically. The regime of small
disorder is addressed, and the enhancement of the critical temperature by
disorder is found both in the mean field approximation and from the analysis of
the zero temperature spin stiffness. Due to disorder, the spin wave
fluctuations around the ferromagnetically ordered state acquire a finite mass.
At large charge carrier band width, the spin wave mass squared becomes
negative, signaling the breakdown of the ferromagnetic ground state and the
onset of a noncollinear magnetic order.",0108396v2
2001-10-16,"Spin Waves, Phase Separation, and Interphase Boundaries in Double Exchange Magnets","We study a classical double exchange magnet with direct antiferromagnetic
superexchange coupling, J, between the localized spins. It is shown that the
de-stabilization of the ferromagnetic ground state with increasing J leads to
phase separation; the latter always preempts the spin-wave instability
(softening of the magnon spectrum). It is also found that the boundaries
separating the ferromagnetic and antiferromagnetic areas of the sample tend to
be abrupt.",0110322v2
2002-05-08,Superconductor-to-Spin-Density-Wave Transition in Quasi-One-Dimensional Metals with Ising Anisotropy,"We study a mechanism for superconductivity in quasi-one-dimensional materials
with Ising anisotropy. In an isolated chain Ising anisotropy opens a spin gap;
if inter-chain coupling is sufficiently weak, single particle hopping is
suppressed and the physics of coupled chains is controlled by a competition
between pair hopping and exchange interaction. Spin density wave and triplet
superconductivity phases are found separated by a first order phase transition.
For particular parameter values a second order transition described by SO(4)
symmetry is found.",0205166v1
2002-09-23,Rigorous Proof of Pseudospin Ferromagnetism in Two-Component Bosonic Systems with Component-Independent Interactions,"For a two-component bosonic system, the components can be mapped onto a
pseudo-spin degree of freedom with spin quantum number S=1/2. We provide a
rigorous proof that for a wide-range of real Hamiltonians with component
independent mass and interaction, the ground state is a ferromagnetic state
with pseudospin fully polarized. The spin-wave excitations are studied and
found to have quadratic dispersion relations at long wave length.",0209529v1
2003-02-24,Study of low-energy magnetic excitations in single-crystalline CeIn3 by inelastic neutron scattering,"Inelastic neutron scattering experiments were performed on single crystals of
the heavy-fermion compound CeIn$_{3}$ for temperatures below and above the
N\'eel temperature, $T_N$. In the antiferromagnetically ordered phase,
well-defined spin-wave excitations with a bandwidth of 2 meV are observed. The
spin waves coexist with quasielastic (QE) Kondo-type spin-fluctuations and
broadened crystal-field (CF) excitations below $T_N$. Above $T_N$, only the QE
and CF excitations persist, with a weak temperature dependence.",0302487v1
2003-04-02,Current-induced transverse spin wave instability in a thin nanomagnet,"We show that an unpolarized electric current incident perpendicular to the
plane of a thin ferromagnet can excite a spin-wave instability transverse to
the current direction if source and drain contacts are not symmetric. The
instability, which is driven by the current-induced ``spin-transfer torque'',
exists for one current direction only.",0304069v2
2003-06-30,A chiral spin liquid wave function and the Lieb-Schulz-Mattis theorem,"We study a chiral spin liquid wave function defined as a Gutwziller projected
BCS state with a complex pairing function. After projection, spontaneous
dimerization is found for any odd but finite number of chains, thus satisfying
the Lieb-Schultz-Mattis theorem, whereas for even number of chains there is no
dimerization. The two-dimensional thermodynamic limit is consistently reached
for large number of chains since the dimer order parameter vanishes in this
limit. This property clearly supports the possibility of a spin liquid ground
state in two dimensions with a gap to all {\em physical} excitations and with
no broken translation symmetry.",0306732v1
2003-07-09,Photoemission study of the spin-density wave state in thin films of Cr,"Angle-resolved photoemission (PE) was used to characterize the spin-density
wave (SDW) state in thin films of Cr grown on W(110). The PE data were analysed
using results of local spin density approximation layer-Korringa-Kohn-Rostoker
calculations. It is shown that the incommensurate SDW can be monitored and
important parameters of SDW-related interactions, such as coupling strength and
energy of collective magnetic excitations, can be determined from the
dispersion of the renormalized electronic bands close to the Fermi energy. The
developed approach can readily be applied to other SDW systems including
magnetic multilayer structures.",0307196v1
2004-01-24,Static and Dynamic Properties of Antiferromagnetic Heisenberg Ladders: Fermionic versus Bosonic Approaches,"In terms of spinless fermions via the Jordan-Wigner transformation along a
snake-like path and spin waves modified so as to restore the sublattice
symmetry, we investigate static and dynamic properties of two-leg
antiferromagnetic Heisenberg ladders. The specific heat is finely reproduced by
the spinless fermions, whereas the magnetic susceptibility is well described by
the modified spin waves. The nuclear spin-lattice relaxation rate is discussed
in detail with particular emphasis on its novel field dependence.",0401477v1
2004-06-05,Perturbative calculation of the spin-wave dispersion in a disordered double-exchange model,"We study the spin-wave dispersion of localized spins in a disordered
double-exchange model using the perturbation theory with respect to the
strength of the disorder potential. We calculate the dispersion upto the
next-leading order, and extensively examine the case of one-dimension. We show
that in that case, disorder yields anomalous gapped-like behavior at the Fermi
wavenumber of the conduction electrons.",0406134v1
2005-04-26,Spin-Polarized Standing Waves in the Fermi Surface of a Ferromagnetic Thin Film,"The spin-selective electron reflection at a ferromagnetic-paramagnetic
interface is investigated using Fe films on a W(110) substrate. Angle-resolved
photoemission of the majority and minority Fermi surfaces of the Fe film is
used to probe standing wave formation. Intense quantum well states resulting
from interfacial reflection are observed exclusively for majority states. Such
high spin polarization is explained by the Fermi surface topology of the
connecting substrate, and we argue that Fe/W is a particularly suitable
interface for that purpose.",0504670v1
2006-06-07,Pseudogap enhancement due to magnetic impurities in d-density waves,"We study the effect of quantum magnetic impurities on d-wave spin density
waves (d-SDW). The impurity spins are aligned coherently according to the spin
space anisotropy of the condensate. Both the order parameter and transition
temperature increases due to the coherent interplay between magnetic scatterers
and d-SDW. This can explain the recent experimental data on the pseudogap
enhancement of Ni substituted NdBa_2{Cu_{1-y}Ni_y}O_6.8 from Pimenov et al.
(Phys. Rev. Lett. 94, 227003 (2005)).",0606176v1
2006-09-13,Spin-wave dispersion in half-doped LaSrNiO,"Recent neutron scattering measurements reveal spin and charge ordering in the
half-doped nickelate, La$_{3/2}$ Sr$_{1/2}$ NiO$_4$. Many of the features of
the magnetic excitations have been explained in terms of the spin waves of
diagonal stripes with weak single-ion anisotropy. However, an optical mode
dispersing away from the (\pi,\pi) point was not captured by this theory. We
show here that this apparent optical mode is a natural consequence of stripe
twinning in a diagonal stripe pattern with a magnetic coupling structure which
is two-fold symmetric, i.e. one possessing the same spatial rotational symmetry
as the ground state.",0609300v1
1999-10-12,"Gravity Waves, Chaos, and Spinning Compact Binaries","Spinning compact binaries are shown to be chaotic in the Post-Newtonian
expansion of the two body system. Chaos by definition is the extreme
sensitivity to initial conditions and a consequent inability to predict the
outcome of the evolution. As a result, the spinning pair will have
unpredictable gravitational waveforms during coalescence. This poses a
challenge to future gravity wave observatories which rely on a match between
the data and a theoretical template.",9910040v3
1994-09-23,Motion of Spin-1/2 Particles in External Gravitational and Electromagnetic Fields,"(Talk presented at the 7th Marcel Grossmann Meeting on General Relativity,
Stanford, CA, July 24-30, 1994) We study the semi-classical limit of the
solution of the Dirac equation in a background electromagnetic/gravitational
plane wave. We show that the exact solution corresponding to an asymptotically
fixed incoming momentum satisfies constraints consistent with the classical
notion of a spinning particle. In order to further analyze the motion of a
spinning particle in this external inhomogeneous field one has to consider
wave-packet superpositions of these exact solutions. We are currently
investigating the existence of a classical theory of a phenomenological spin
tensor which reproduces our quantum-mechanical results.",9409147v1
2003-06-28,On Equations for a Spin-2 Particle in External Gravitational Field,"30-component, of the first order, equation for a spin 2 particle, equivalent
to the second order Pauli-Fierz one, is generalized to presence of an external
electromagnetic field as well as a curved background space-time geometry. The
essential property of the generally covariant wave equation obtained is that
here from the very beginning, in accordance with requirement of the Pauli-Fierz
approach, a set of additional relations on 30-component wave function for
eliminating complementary spin 0 and spin 1 fields is present at the starting
equation.",0306286v1
2004-08-05,The novel aspect of hydrogen atom: the fine structure and spin can be derived by single component wavefunction,"The fine structure of hydrogen energy was calculated by using the usual
momentum-wavefunction relation directly, rather than establishing the
well-known Dirac wave equation. As the results, the energy levels are
completely the same as that of the Dirac wave equation, while the wavefunction
is single component that is quite different from Dirac's four component
wavefunction, the most important thing is that the present calculation brings
out electronic spin in a new way which has never been reported and indicates
that the electronic spin is a kind of orbital motion.",0408025v1
2007-06-14,Spin-waves in a complex magnetic system: nonextensive approach,"In this paper we analyze the spin-wave excitations (magnons) of an
inhomogeneous spin system within the Boltzmann-Gibbs framework and then connect
the results with the nonextensive approach (in the sense of Tsallis
statistics). Considering an equivalence between those two frameworks, we could
connect the entropic parameter q with moments of the distribution of exchange
integrals of the inhomogenous system. It ratifies the idea that the entropic
parameter is connected to the microscopic properties of the system.",0706.2201v2
2009-06-30,Quantum phase transition of the 103mRh spin-density wave,"We induce a quantum phase transition of the 103mRh excitation at the critical
density of 10^{12} cm^{-3} by bremsstrahlung pumping at 300 K. A massive 103mRh
spin-density wave carrying a spin current moves on the identical 103Rh matrix
like a quantum fluid. The collapse-and-revival spectral evolution indicates
that the collective nuclear excitation undergoes dynamic Bose-Einstein
condensation. Applying an external magnetic field, we observe the
Onsager-Feynman quantization, which gives further evidence of the superfluidic
phase.",0906.5417v1
2009-10-15,Dixon's extended bodies and impulsive gravitational waves,"The ""reaction"" of an extended body to the passage of an exact plane
gravitational wave is discussed following Dixon's model. The analysis performed
shows several general features, e.g. even if initially absent, the body
acquires a spin induced by the quadrupole structure, the center of mass moves
from its initial position, as well as certain ""spin-flip"" or ""spin-glitch""
effects which are being observed.",0910.2846v1
2010-11-04,Spin wave calculation of the field-dependent magnetization pattern around an impurity in Heisenberg antiferromagnets,"We consider the magnetic-field dependent spatial magnetization pattern around
a general impurity embedded in a Heisenberg antiferromagnet using both an
analytical and a numerical spin wave approach. The results are compared to
quantum Monte Carlo simulations. The decay of the magnetization pattern away
from the impurity follows a universal form which reflects the properties of the
pure antiferromagnetic Heisenberg model. Only the overall magnitude of the
induced magnetization depends also on the size of the impurity spin and the
impurity coupling.",1011.1271v1
2010-11-15,Study of the Spin-weighted Spheroidal Equation in the Case of s=1,"We present series study of using the method of super-symmetric quantum
mechanics(SUSYQM) solving the spin-weighted spheroidal wave equation. In this
paper, we obtain the first four terms of super-potential of the spin-weighted
spheroidal wave equation in the case of s=1. These results may help summary the
general form for the n-th term of the super-potential, which is proved correct
by means of induction. We finally compute the ground eigenvalues and ground
eigenfunction. All the results may be of significative for studies of
electromagnetic radiation processes near rotating black holes and compute
radiation reaction in curved space-time.",1011.4045v1
2010-11-19,Spin waves in magnetic quantum wells with Coulomb interaction and $sd$ exchange coupling,"We theoretically describe the spin excitation spectrum of a two dimensional
electron gas embedded in a quantum well with localized magnetic impurities.
Compared to the previous work, we introduce equations that allow to consider
the interplay between the Coulomb interaction of delocalized electrons and the
$sd$ exchange coupling between electrons and magnetic impurities. Strong
qualitative changes are found : mixed waves propagate below the single particle
continuum, an anticrossing gap is open at a specific wavevector and the kinetic
damping due to the electron motion strongly influences the coupling strength
between electrons and impurities spins.",1011.4422v1
2011-04-01,Spin waves cause non-linear friction,"Energy dissipation is studied for a hard magnetic tip that scans a soft
magnetic substrate. The dynamics of the atomic moments are simulated by solving
the Landau-Lifshitz-Gilbert (LLG) equation numerically. The local energy
currents are analysed for the case of a Heisenberg spin chain taken as
substrate. This leads to an explanation for the velocity dependence of the
friction force: The non-linear contribution for high velocities can be
attributed to a spin wave front pushed by the tip along the substrate.",1104.0197v2
2011-07-05,Magnetic field and quark matter in the core,"Magnetic properties of quark matter are discussed in the light of the
observation of pulsars. Our works about spontaneous spin polarization and spin
density wave are reviewed and their implications on compact-star phenomena are
discussed. In particular, the former subject may be directly related to the
origin of strong magnetic fields. An inhomogeneous state emerges following the
chiral transition, where a kind of spin density wave develops.",1107.0807v2
2011-09-02,Gravitational Waves and the Maximum Spin Frequency of Neutron Stars,"In this Letter we re-examine the idea that gravitational waves are required
as a braking mechanism to explain the observed maximum spin-frequency of
neutron stars. We show that for millisecond X-ray pulsars, the existence of
spin equilibrium as set by the disk/magnetosphere interaction is sufficient to
explain the observations. We show as well that no clear correlation exists
between the neutron star magnetic field B and the X-ray outburst luminosity Lx
when considering an enlarged sample size of millisecond X-ray pulsars.",1109.0536v1
2011-12-13,Spectral properties of one-dimensional spiral spin density wave states,"We provide a full characterization of the spectral properties of spiral spin
density wave (SSDW) states which emerge in one-dimensional electron systems
coupled to localized magnetic moments or quantum wires with spin-orbit
interactions. We derive analytic results for the spectral function, local
density of states and optical conductivity in the low-energy limit by using
field theory techniques. We identify various collective modes and show that the
spectrum strongly depends on the interaction strength between the electrons.
The results provide characteristic signatures for an experimental detection of
SSDW states.",1112.3045v2
2012-03-07,Temperature Induced Spin Density Wave in Magnetic Doped Topological Insulators,"We study the magnetic properties of topological insulators doped with
isoelectronic magnetic impurities. We obtain that at zero temperature the
impurities order ferromagnetically, but when raising the temperature the
topological insulator undergoes a first order phase transition to a spin
density wave phase before the system reaches the paramagnetic phase. The origin
of this phase is the non-trivial dependence of the topological insulator spin
susceptibility on the momentum. We analyze the coupling of the non-uniform
magnetic phase with the Dirac electronic system that occurs at the surfaces of
the topological insulators.",1203.1436v2
2012-03-13,Spin induced multipole moments for the gravitational wave amplitude from binary inspirals to 2.5 Post-Newtonian order,"Using the NRGR effective field theory formalism we calculate the remaining
source multipole moments necessary to obtain the spin contributions to the
gravitational wave amplitude to 2.5 Post-Newtonian (PN) order. We also
reproduce the tail contribution to the waveform linear in spin at 2.5PN arising
from the nonlinear interaction between the current quadrupole and the mass
monopole.",1203.2962v2
2012-06-15,Kinks and waterfalls as signatures of competing order in angle-resolved photoemission spectra of La_{2-x}Sr_xCuO_4,"We show that the so-called kinks and waterfalls observed in angle-resolved
photoemission spectra of La2-xSrxCuO4, a prototypical high-Tc superconducting
cuprate, result from the coupling of quasiparticles with two distinct nearly
critical collective modes with finite characteristic wave vectors, typical of
charge and spin fluctuations near a stripe instability. Both phonon-like charge
and spin collective modes are needed to account for the kinked quasiparticle
dispersions. This clarifies the long-standing question whether kinks are due to
phonons or spin waves and the nature of the bosonic mediators of the
electron-electron effective interaction in La2-xSrxCuO4.",1206.3427v1
2012-12-17,Electromagnetic soliton-particle with spin and magnetic moment,"Electromagnetic soliton-particle with both quasi-static and quick-oscillating
wave parts is considered. Its mass, spin, charge, and magnetic moment appear
naturally when the interaction with distant solitons is considered. The
substantiation of Dirac equation for the wave part of the interacting
soliton-particle is given.",1212.4468v1
2013-03-31,Semi classical modeling of isotropic Non-Heisenberg magnets for spin S=1 and linear quadrupole excitation dynamics,"In this paper, equations describing one-dimensional Non-Heisenberg model are
studied by use of generalized coherent states in real parameterization and then
dissipative spin wave equation for dipole and quadrupole branches is obtained
if there is a small linear excitation from the ground state. Finally, it is
shown that for such exchange-isotropy Hamiltonians, optical branch of spin wave
is non-dissipative.",1304.0245v1
2013-04-02,Asymptotic spectrum of the oblate spin-weighted spheroidal harmonics: a WKB analysis,"Spin-weighted spheroidal harmonics play a central role in the mathematical
description of diverse physical phenomena, including black-hole perturbation
theory and wave scattering. We present a novel and compact derivation of the
asymptotic eigenvalues of these important functions. Our analysis is based on a
simple trick which transforms the corresponding spin-weighted spheroidal
angular equation into a Schr\""odinger-like wave equation which is amenable to a
standard WKB analysis.",1304.0529v1
2013-09-19,Equivariant and self-similar standing waves for a Hamiltonian hyperbolic-hyperbolic spin-field system,"In this paper we study the existence of special symmetric solutions to a
Hamiltonian hyperbolic-hyperbolic coupled spin-field system, where the spins
are maps from $\mathbb R^{2+1}$ into the sphere $\S^2$ or the pseudo-sphere
$\H^2$. This model was introduced in \cite{Martina} and it is also known as the
{\it hyperbolic-hyperbolic generalized Ishimori system}. Relying on the
hyperbolic coordinates introduced in \cite{KNZ11}, we prove the existence of
equivariant standing waves in both regular hyperbolic coordinates as well as
similarity variables, and describe their asymptotic behaviour.",1309.5066v2
2013-10-12,Inversion Phenomena of the Anisotropies of the Hamiltonian and the Wave Function in Quantum Spin Chains,"We investigate the inversion phenomena between the XXZ anisotropies of the
Hamiltonian and the wave function in quantum spin chains. We focus on the S=1/2
geometrically frustrated 3-leg ladder system with the XXZ interaction
anisotropy. By use of the degenerate perturbation theory from the strong rung
coupling limit, we have obtained the ground-state phase diagram. In some
parameter regions, the Tomonaga-Luttinger spin liquid state is realized in
spite of the Ising-like anisotropy, and the Neel state in spite of the XY-like
anisotropy.",1310.3394v1
2014-05-07,Spin structure factor and quantum phases of frustrated spin-1/2 chains,"The static structure factor S(q) of frustrated spin-1/2 chains with isotropic
exchange and a singlet ground state (GS) diverges at wave vector q_m when the
GS has quasi-long-range order (QLRO) with periodicity 2\pi/q_m but S(q_m) is
finite in bond-order-wave (BOW) phases with finite-range spin correlations.
Exact diagonalization and density matrix renormalization group (DMRG)
calculations of S(q) indicate a decoupled phase with QLRO and q_m = \pi/2 in
chains with large antiferromagnetic exchange between second neighbors. S(q_m)
identifies quantum phase transitions based on GS spin correlations.",1405.1578v1
2014-08-21,Scattering by an electromagnetic radiation field,"Motion of test particles in the gravitational field associated with an
electromagnetic plane wave is investigated. The interaction with the radiation
field is modeled by a force term {\it \`a la} Poynting-Robertson entering the
equations of motion given by the 4-momentum density of radiation observed in
the particle's rest frame with a multiplicative constant factor expressing the
strength of the interaction itself. Explicit analytical solutions are obtained.
Scattering of fields by the electromagnetic wave, i.e., scalar (spin 0),
massless spin $\frac12$ and electromagnetic (spin 1) fields, is studied too.",1408.4958v1
2014-11-14,Magnetic order and spin excitations in layered Heisenberg antiferromagnets with compass-model anisotropies,"The spin-wave excitation spectrum, the magnetization, and the N\'{e}el
temperature for the quasi-two-dimensional spin-1/2 antiferromagnetic Heisenberg
model with compass-model interaction in the plane proposed for iridates are
calculated in the random phase approximation. The spin-wave spectrum agrees
well with data of Lanczos diagonalization. We find that the Neel temperature is
enhanced by the compass-model interaction and is close to the experimental
value for Ba2IrO4.",1411.3920v2
2015-04-03,Solitons in a continuous classical Haldane-Shastry spin chain,"Motivated by Polychronakos' discovery that solitons exist in the hydrodynamic
equations of continuum version of the Calogero model, we seek solitons in the
classical dynamics of a continuum version of the Haldane-Shastry spin chain. We
have obtained analytic multi-lump solitary wave solutions for our spin-field
equation, and these solutions possess interesting topological features. We have
performed numerical collision experiments showing that these solitary waves
survive collisions, and thus suggest the existence of true multi-soliton
solutions.",1504.00873v1
2016-01-30,Low-Temperature Spin-Wave Approximation for the Heisenberg Ferromagnet,"We study the low temperature thermodynamics of the quantum Heisenberg
ferromagnet in three dimension for any value of the spin $ S \geq 1/2 $. We
report on a rigorous proof of the validity of the spin-wave approximation for
the excitation spectrum, at the level of the first non-trivial contribution to
the free energy as the inverse temperature $ \beta \to \infty $.",1602.00155v1
2019-09-10,Enhanced Detectability of Spinning Primordial Black Holes,"Primordial black holes which are produced during an epoch of matter
domination are expected to spin rapidly. It is shown that this leads to an
enhancement of the detectability of the stochastic gravitational-wave
background from their mergers. For a specific model, we explicitly demonstrate
that this yields a $50\,\%$ increase of the gravitational-wave amplitude as
compared to the non-spinning case.",1909.04742v2
2020-07-30,Derivation of the Half-Wave Maps Equation from Calogero--Moser Spin Systems,"We prove that the energy-critical half-wave maps equation \[ \partial_t
\mathbf{S} =\mathbf{S} \times |\nabla| \mathbf{S}, \quad (t,x) \in \mathbb{R}
\times \mathbb{T} \] arises as an effective equation in the continuum limit of
completely integrable Calogero-Moser classical spin systems with inverse square
$1/r^2$ interactions on the circle. We study both the convergence to
global-in-time weak solutions in the energy class as well as short-time strong
solutions of higher regularity. The proofs are based on Fourier methods and
suitable discrete analogues of fractional Leibniz rules and Kato-Ponce-Vega
commutator estimates.
  In a companion paper, we further extend our arguments to study the real line
case and more general spin interactions.",2007.15323v1
2020-12-02,Effects of exchange distortions in the magnetic Kagome lattice,"This study examines the effect of distorted triangular magnetic interactions
in the Kagome lattice. Using a Holstein-Primakoff expansion, we determine the
analytical solutions for classical energies and the spin-wave modes for various
magnetic configurations. By understanding the magnetic phase diagram, we
characterize the changes in the spin waves and examine the spin distortions of
the ferromagnetic (FM), Antiferrimagnetic (AfM), and 120$^{\circ}$ phases that
are produced by variable exchange interactions and lead to various
non-collinear phases, which provides a deeper understanding of the magnetic
fingerprints of these configurations for experimental characterization and
identification.",2012.00910v1
2021-01-18,Quantum fluctuation effects on the ordered Moments in a two dimensional frustrated ferrimagnet,"We propose a novel two-dimensional (2D)frustrated quantum spin-1/2
anisotropic Heisenberg model with alternating ferromagnetic and
antiferromagnetic magnetic chains along one direction and antiferromagnetic
interactions along the other. The (mean-field) ground state is ferrimagnetic in
certain range of the interaction space. Spin-wave theory analysis of the
reduction of ordered moments at inequivalent spin sites and the instability of
the spin waves suggest a quantum phase transition which has the characteristics
of both the frustrated two-dimensional antiferromagnetic S=1/2 ($J_1, J_2$)
model and 1D S$_1$=1, S$_2$=1/2 quantum ferrimagnetic model.",2101.07300v1
2021-12-27,Penrose limit of MNa solution and spin chains in three-dimensional field theories,"In three dimensions, a theory with spontaneous breaking of supersymmetry was
described holographically by the Maldacena-Nastase (MNa) solution. We revisit
the issue of its Penrose limit, and compare the resulting pp wave and its
string eigenstates to a sector of the theory on 5-branes reduced on $S^3$, and
a spin chain-like system. We obtain many of the features of the pp wave
analysis, but a complete matching still eludes us. We suggest possible
explanations for the resulting partial mismatch, and compare against other spin
chains for 3-dimensional field theories with gravity duals.",2112.13802v2
2022-04-19,Spin correlations in the frustrated ferro-antiferromagnet SrZnVO(PO4)2 near saturation,"Single crystal elastic and inelastic neutron scattering experiments are
performed on the frustrated ferro-antiferromagnet SrZnVO(PO4)2 in high magnetic
fields. The fully polarized state, the presaturation phase and the
columnar-antiferromagnetic phase just bellow the presaturation phase were
investigated. The observed renormalization of spin wave bandwidths,
re-distribution of intensities between different branches and non-linearities
in the magnetization curve are all indicative of strong deviations from
classical spin wave theory. The previously observed presaturation transition is
attributed to a staggered pattern of Dzyaloshinskii-Moriya interactions.",2204.08778v2
2023-03-20,Electron Wave Spin in Excited States,"The wave spin of an electron can be fully characterized by the current
density calculated from the exact four-spinor solution of the Dirac equation.
In the excited states of the electron in a magnetic field-free quantum well,
the current density has a multiple vortex topology. The interaction of the
current with a magnetic potential produces a finer structure of anomalous
Zeeman splitting. When the magnetic potential is comparable to the size of the
individual vortices, fractional or zero spin effects can be observed.",2303.10855v1
2023-09-09,Teukolsky-like equations with various spins in spherically symmetric spacetime,"We study the wave equations with various spins on the background of the
general spherically symmetric spacetime. We obtain the unified expression of
the Teukolsky-like master equations and the corresponding radial equations with
the general spins. We also discuss the gauge dependence in the
gravitational-wave equations, which have appeared in the previous studies.",2309.04758v2
2015-12-24,Shedding Light on Diphoton Resonances,"The experimental and theoretical implications of heavy digauge boson
resonances that couple to, or are comprised of, new charged and strongly
interacting matter are investigated. Observation and measurement of ratios of
the resonant digauge boson channels $WW$, $ZZ$, $\gamma \gamma$, $Z \gamma$,
and $gg$ in the form of dijets, provide a rather direct -- and for some ratios
a rather robust -- probe of the gauge representations of the new matter. For a
spin-zero resonance with the quantum numbers of the vacuum, the ratios of
resonant $WW$ and $ZZ$ to $\gamma \gamma$ channels, as well as the longitudinal
versus transverse polarization fractions in the $WW$ and $ZZ$ channels, provide
probes for possible mixing with the Higgs boson, while di-Higgs and ditop
resonant channels, $hh$ and $tt$, provide somewhat less sensitivity. We present
a survey of possible underlying models for digauge boson resonances by
considering various limits for the mass of the new charged and strongly
interacting matter fields as well as the confinement scale of new hypergauge
interactions under which they may also be charged. In these limits, resonances
may be included as elementary weakly coupled spin-zero states or can correspond
to hyperglueballs, hyperonia, or pseudoscalar hypermesons. For each of these
cases, we make predictions for additional states that could be resonantly or
pair produced and observed at the Large Hadron Collider or in future collider
experiments. Heavy digauge boson resonances can provide a unified explanation
for a number of small discrepancies and excesses in reported data from the
Large Hadron Collider.",1512.07733v3
2008-05-05,On-chip Integration of High-Frequency Electron Paramagnetic Resonance Spectroscopy and Hall-Effect Magnetometry,"A sensor that integrates high sensitivity micro-Hall effect magnetometry and
high-frequency electron paramagnetic resonance spectroscopy capabilities on a
single semiconductor chip is presented. The Hall-effect magnetometer was
fabricated from a two dimensional electron gas GaAs/AlGaAs heterostructure in
the form of a cross, with a 50x50 um2 sensing area. A high-frequency microstrip
resonator is coupled with two small gaps to a transmission line with a 50 Ohms
impedance. Different resonator lengths are used to obtain quasi-TEM fundamental
resonant modes in the frequency range 10-30 GHz. The resonator is positioned on
top of the active area of the Hall-effect magnetometer, where the magnetic
field of the fundamental mode is largest, thus optimizing the conversion of
microwave power into magnetic field at the sample position. The two gaps
coupling the resonator and transmission lines are engineered differently. The
gap to the microwave source is designed to optimize the loaded quality factor
of the resonator (Q = 150) while the gap for the transmitted signal is larger.
This latter gap minimizes losses and prevents distortion of the resonance while
enabling measurement of the transmitted signal. The large filling factor of the
resonator permits sensitivities comparable to that of high-quality factor
resonant cavities. The integrated sensor enables measurement of the
magnetization response of micron scale samples upon application of microwave
fields. In particular, the combined measurement of the magnetization change and
the microwave power under cw microwave irradiation of single crystal of
molecular magnets is used to determine of the energy relaxation time of the
molecular spin states. In addition, real time measurements of the magnetization
dynamics upon application of fast microwave pulses are demonstrated",0805.0565v1
2021-07-12,Avalanches and many-body resonances in many-body localized systems,"We numerically study both the avalanche instability and many-body resonances
in strongly-disordered spin chains exhibiting many-body localization (MBL). We
distinguish between a finite-size/time MBL regime, and the asymptotic MBL
phase, and identify some ""landmarks"" within the MBL regime. Our first landmark
is an estimate of where the MBL phase becomes unstable to avalanches, obtained
by measuring the slowest relaxation rate of a finite chain coupled to an
infinite bath at one end. Our estimates indicate that the actual MBL-to-thermal
phase transition, in infinite-length systems, occurs much deeper in the MBL
regime than has been suggested by most previous studies. Our other landmarks
involve system-wide resonances. We find that the effective matrix elements
producing eigenstates with system-wide resonances are enormously broadly
distributed. This means that the onset of such resonances in typical samples
occurs quite deep in the MBL regime, and the first such resonances typically
involve rare pairs of eigenstates that are farther apart in energy than the
minimum gap. Thus we find that the resonance properties define two landmarks
that divide the MBL regime in to three subregimes: (i) at strongest disorder,
typical samples do not have any eigenstates that are involved in system-wide
many-body resonances; (ii) there is a substantial intermediate regime where
typical samples do have such resonances, but the pair of eigenstates with the
minimum spectral gap does not; and (iii) in the weaker randomness regime, the
minimum gap is involved in a many-body resonance and thus subject to level
repulsion. Nevertheless, even in this third subregime, all but a vanishing
fraction of eigenstates remain non-resonant and the system thus still appears
MBL in many respects. Based on our estimates of the location of the avalanche
instability, it might be that the MBL phase is only part of subregime (i).",2107.05642v3
1998-10-14,Spin relaxation in Mn12-acetate,"We present a comprehensive derivation of the magnetization relaxation in a
Mn12-acetate crystal based on thermally assisted spin tunneling induced by
quartic anisotropy and weak transverse magnetic fields. The overall relaxation
rate as function of the magnetic field is calculated and shown to agree well
with data including all resonance peaks. The Lorentzian shape of the resonances
is also in good agreement with recent data. A generalized master equation
including resonances is derived and solved exactly. It is shown that many
transition paths with comparable weight exist that contribute to the relaxation
process. Previously unknown spin-phonon coupling constants are calculated
explicitly.",9810156v3
2000-02-01,Resonant Spin Excitation in an Overdoped High Temperature Superconductor,"An inelastic neutron scattering study of overdoped Bi_2Sr_2CaCu_2O_{8+\delta}
$ (T_c = 83 K) has revealed a resonant spin excitation in the superconducting
state. The mode energy is E_res=38 meV, significantly lower than in optimally
doped Bi_2Sr_2CaCu_2O_{8+\delta} (T_c = 91 K, E_ res =43 meV). This
observation, which indicates a constant ratio E_res /k_B T_c \sim 5.4, helps
resolve a long-standing controversy about the origin of the resonant spin
excitation in high-temperature superconductors.",0002013v3
2000-09-05,Where is the pi particle?,"We discuss the interplay of particle-particle and particle-hole spin-triplet
channels in high-T_c superconductors using a quasiparticle dispersion motivated
by angle-resolved photoemission. Within a generalized RPA, we find a well
defined antibound state of two holes, the pi resonance of Demler and Zhang, as
well as a bound state of a particle and a hole, the spin exciton. We show that
the energy of the pi resonance always exceeds 2 Delta, twice the maximum d-wave
gap, therefore the neutron resonance observed in the cuprates around energy
Delta is most likely a spin exciton. At the same time, we speculate that the pi
particle can exist at higher energies and might be observed in neutron
scattering around 100 meV.",0009072v1
2005-07-29,Resonant Pair Exchange and Percolation in the Disordered Hubbard Model,"We show that the effect of disorder on a Mott-Hubbard insulator of
interacting electrons produces a quantum phase transition from an
antiferromagnetic to a paramagnetic phase governed by a percolation of the
singly occupied weakly disordered sites. Near the transition, we propose that a
new type of defect, formed by the resonant exchange between a spin singlet and
a doubly occupied site with an attractive disorder potential, plays an
important role. These resonant pair exchange defects reduce the staggered
magnetization but enhance the coupling of the two spins and produce
characteristic signatures in the temperature dependent specific heat and the
non-Curie spin susceptibility, at temperatures on the order the hopping t,
higher than the typical exchange scale J.",0507701v1
1998-12-16,Effects of magnetohydrodynamics matter density fluctuations on the solar neutrino resonant spin-flavor precession,"Taking into account the stringent limits from helioseismology observations on
possible matter density fluctuations described by magnetohydrodynamics theory,
we find the corresponding time variations of solar neutrino survival
probability due to the resonant spin-flavor precession phenomenon with
amplitude of order O(10%). We discuss the physics potential of high statistics
real time experiments, like as Superkamiokande, to observe the effects of such
magnetohydrodynamics fluctuations on their data. We conclude that these
observations could be thought as a test of the resonant spin-flavor precession
solution to the solar neutrino anomaly.",9812390v1
1999-06-28,Influence of Non-Resonant Effects on the Dynamics of Quantum Logic Gates at Room Temperature,"We study numerically the influence of non-resonant effects on the dynamics of
a single $\pi$-pulse quantum CONTROL-NOT (CN) gate in a macroscopic ensemble of
fo ur-spin molecules at room temperature. The four nuclear spins in each
molecule r epresent a four-qubit register. The qubits are ``labeled'' by the
characteristic frequencies, $\omega_k$, ($k=0$ to 3) due to the Zeeman
interaction of the nuclear spins with the magnetic field. The qubits interact
with each other through an Ising interaction of strength $J$. T he paper
examines the feasibility of implementing a single-pulse quantum CN gate in an
ensemble of quantum molecules at room temperature. We determine a paramet er
region, $\omega_k$ and $J$, in which a single-pulse quantum CN gate can be i
mplemented at room temperature. We also show that there exist characteristic
cri tical values of parameters,
$\Delta\omega_{cr}\equiv|\omega_{k^\prime}-\omega_k|_{cr}$ and $J_{cr}$, such
that for $J<J_{cr}$ and
$\Delta\omega_k\equiv|\omega_{k^\prime}-\omega_k|<\Delta\omega_{cr}$,
non-resonant effects are sufficient to d estroy the dynamics required for
quantum logic operations.",9906109v1
2007-10-22,Microwave band on-chip coil technique for single electron spin resonance in a quantum dot,"Microwave band on-chip microcoils are developed for the application to single
electron spin resonance measurement with a single quantum dot. Basic properties
such as characteristic impedance and electromagnetic field distribution are
examined for various coil designs by means of experiment and simulation. The
combined setup operates relevantly in the experiment at dilution temperature.
The frequency responses of the return loss and Coulomb blockade current are
examined. Capacitive coupling between a coil and a quantum dot causes photon
assisted tunneling, whose signal can greatly overlap the electron spin
resonance signal. To suppress the photon assisted tunneling effect, a technique
for compensating for the microwave electric field is developed. Good
performance of this technique is confirmed from measurement of Coulomb blockade
oscillations.",0710.3986v2
2008-10-10,Deciphering the spin of new resonances in Higgsless models,"We study the potential of the CERN Large Hadron Collider (LHC) to probe the
spin of new massive vector boson resonances predicted by Higgsless models. We
consider its production via weak boson fusion which relies only on the coupling
between the new resonances and the weak gauge bosons. We show that the LHC will
be able to unravel the spin of the particles associated with the partial
restoration of unitarity in vector boson scattering for integrated luminosities
of 150-560 fb^-1, depending on the new state mass and on the method used in the
analyses.",0810.1952v3
2009-01-31,Density of States in the Magnetic Ground State of the Friedel-Anderson Impurity,"By applying a magnetic field whose Zeeman energy exceeds the Kondo energy by
an order of magnitude the ground state of the Friedel-Anderson impurity is a
magnetic state. In recent years the author introduced the Friedel Artificially
Inserted Resonance (FAIR) method to investigate impurity properties. Within
this FAIR approach the magnetic ground state is derived. Its full excitation
spectrum and the composition of the excitations is calculated and numerically
evaluated. From the excitation spectrum the electron density of states is
calculated. Majority and minority d-resonances are obtained. The width of the
resonances is about twice as wide as the mean field theory predicts. This
broadening is due to the fact that any change of the occupation of the d-state
in one spin band changes the eigenstates in the opposite spin band and causes
transitions in both spin bands. This broadening reduces the height of the
resonance curve and therefore the density of states by a factor of two. This
yields an intuitive understanding for a previous result of the FAIR approach
that the critical value of the Coulomb interaction for the formation of a
magnetic moment is twice as large as the mean field theory predicts.",0902.0033v1
2009-03-05,Static and fluctuating stripe order observed by resonant soft x-ray diffraction in La1.8Sr0.2NiO4,"We studied the stripe phase of La1.8Sr0.2NiO4 using neutron diffraction,
resonant soft x-ray diffraction (RSXD) at the Ni L2,3 edges, and resonant x-ray
diffraction (RXD) at the Ni K threshold. Differences in the q-space resolution
of the different techniques have to be taken into account for a proper
evaluation of diffraction intensities associated with the spin and charge order
superstructures. We find that in the RSXD experiment the spin and charge order
peaks show the same temperature dependence. In the neutron experiment by
contrast, the spin and charge signals follow quite different temperature
behaviors. We infer that fluctuating magnetic order contributes considerably to
the magnetic RSXD signal and we suggest that this result may open an
interesting experimental approach to search for fluctuating order in other
systems by comparing RSXD and neutron diffraction data.",0903.0994v1
2010-03-25,Nuclear-spin-independent short-range three-body physics in ultracold atoms,"We investigate three-body recombination loss across a Feshbach resonance in a
gas of ultracold 7Li atoms prepared in the absolute ground state and perform a
comparison with previously reported results of a different nuclear-spin state
[N. Gross et.al., Phys. Rev. Lett. 103 163202, (2009)]. We extend the
previously reported universality in three-body recombination loss across a
Feshbach resonance to the absolute ground state. We show that the positions and
widths of recombination minima and Efimov resonances are identical for both
states which indicates that the short-range physics is nuclear-spin
independent.",1003.4891v4
2010-07-02,Charge order and low frequency spin dynamics in lanthanum cuprates revealed by Nuclear Magnetic Resonance,"We report detailed 17O, 139La, and 63Cu Nuclear Magnetic Resonance (NMR) and
Nuclear Quadrupole Resonance (NQR) measurements in a stripe ordered
La1.875Ba0.125CuO4 single crystal and in oriented powder samples of
La1.8-xEu0.2SrxCuO4. We observe a partial wipeout of the 17O NMR intensity and
a simultaneous drop of the 17O electric field gradient (EFG) at low
temperatures where the spin stripe order sets in. In contrast, the 63Cu
intensity is completely wiped out at the same temperature. The drop of the 17O
quadrupole frequency is compatible with a charge stripe order. The 17O spin
lattice relaxation rate shows a peak similar to that of the 139La, which is of
magnetic origin. This peak is doping dependent and is maximal at x ~ 1/8.",1007.0339v1
2010-10-04,Measuring spin and CP from semi-hadronic ZZ decays using jet substructure,"We apply novel jet techniques to investigate the spin and CP quantum numbers
of a heavy resonance X, singly produced in pp -> X -> ZZ -> l(+)l(-)jj at the
LHC. We take into account all dominant background processes to show that this
channel, which has been considered unobservable until now, can qualify under
realistic conditions to supplement measurements of the purely leptonic decay
channels X -> ZZ -> 4l. We perform a detailed investigation of spin- and
CP-sensitive angular observables on the fully-simulated final state for various
spin and CP quantum numbers of the state X, tracing how potential sensitivity
communicates through all the steps of a subjet analysis. This allows us to
elaborate on the prospects and limitations of performing such measurements with
the semihadronic final state. We find our analysis particularly sensitive to a
CP-even or CP-odd scalar resonance, while, for tensorial and vectorial
resonances, discriminative features are diminished in the boosted kinematical
regime.",1010.0676v2
2010-12-18,Neutron Scattering Studies of spin excitations in hole-doped Ba0.67K0.33Fe2As2 superconductor,"We report inelastic neutron scattering experiments on single crystals of
superconducting Ba0.67K0.33Fe2As2 (Tc = 38 K). In addition to confirming the
resonance previously found in powder samples, we find that spin excitations in
the normal state form longitudinally elongated ellipses along the QAFM
direction in momentum space, consistent with density functional theory
predictions. On cooling below Tc, while the resonance preserves its momentum
anisotropy as expected, spin excitations at energies below the resonance become
essentially isotropic in the in-plane momentum space and dramatically increase
their correlation length. These results suggest that the superconducting gap
structures in Ba0.67Ka0.33Fe2As2 are more complicated than those suggested from
angle resolved photoemission experiments.",1012.4065v2
2011-02-14,Coplanar stripline antenna design for optically detected magnetic resonance on semiconductor quantum dots,"We report on the development and testing of a coplanar stripline antenna that
is designed for integration in a magneto-photoluminescence experiment to allow
coherent control of individual electron spins confined in single self-assembled
semiconductor quantum dots. We discuss the design criteria for such a structure
which is multi-functional in the sense that it serves not only as microwave
delivery but also as electrical top gate and shadow mask for the single quantum
dot spectroscopy. We present test measurements on hydrogenated amorphous
silicon, demonstrating electrically detected magnetic resonance using the
in-plane component of the oscillating magnetic field created by the coplanar
stripline antenna necessary due to the particular geometry of the quantum dot
spectroscopy. From reference measurements using a commercial electron spin
resonance setup in combination with finite element calculations simulating the
field distribution in the structure, we obtain an average magnetic field of
~0.2mT at the position where the quantum dots would be integrated into the
device. The corresponding pi-pulse time of ~0.3us fully meets the requirements
set by the high sensitivity optical spin read-out scheme developed for the
quantum dot.",1102.2860v1
2011-07-21,Theory of quantum energy transfer in spin chains: From superexchange to ballistic motion,"Quantum energy transfer in a chain of two-level (spin) units, connected at
its ends to two thermal reservoirs, is analyzed in two limits: (i) In the
off-resonance regime, when the characteristic subsystem excitation energy gaps
are larger than the reservoirs frequencies, or the baths temperatures are low.
(ii) In the resonance regime, when the chain excitation gaps match populated
bath modes. In the latter case the model is studied using a master equation
approach, showing that the dynamics is ballistic for the particular chain model
explored. In the former case we analytically study the system dynamics
utilizing the recently developed Energy-Transfer Born-Oppenheimer formalism
[Phys. Rev. E {\bf 83}, 051114 (2011)], demonstrating that energy transfers
across the chain in a superexchange (bridge assisted tunneling) mechanism, with
the energy current decreasing exponentially with distance. This behavior is
insensitive to the chain details. Since at low temperatures the excitation
spectrum of molecular systems can be truncated to resemble a spin chain model,
we argue that the superexchange behavior obtained here should be observed in
widespread systems satisfying the off-resonance condition.",1107.4334v1
2011-08-02,Spin noise spectroscopy under resonant optical probing conditions: coherent and non-linear effects,"High sensitivity Faraday rotation spectroscopy is used to measure the
fluctuating magnetization noise of non-interacting rubidium atoms under
resonant and non-resonant optical probing conditions. The spin noise frequency
spectra in dependence on the probe light detuning with respect to the
D2-transition reveals clear signatures of a coherent coupling of the
participating electronic levels. The results are explained by extended Bloch
equations including homogeneous and inhomogeneous broadening mechanisms. Our
measurements further indicate that spin noise originating from excited states
are governed at high intensities by collective effects.",1108.0591v2
2011-08-10,Bias-induced destruction of ferromagnetism and disorder effects in GaMnAs heterostructures,"The magneto-electric properties of resonant tunneling double barrier
structures using GaMnAs for the quantum well is investigated within a
self-consistent Green's function approach and a tight-binding electronic
structure model. The magnetic state of the well is determined self-consistently
by the tunneling current which controls the hole spin density and, hence, the
degree of exchange splitting of the subbands inside the well. Prompted by
recent experiments we compare model systems of increasing defect concentration
(substitutional disorder) regarding their I-V curve, magnetic state, and spin
polarization. We predict that, near resonance, the ferromagnetic order which
may be present at zero bias in the GaMnAs well tends to be destroyed. Resonance
peaks are found to be more sensitive to disorder than ferromagnetic ordering
and spin polarization of the steady-state current.",1108.2108v1
2012-01-13,"Density, spin, and pairing instabilities in polarized ultracold Fermi gases","We study the influence of population imbalance on the pairing, spin, and
density instabilities of a two component ideal Fermi gas after a sudden quench
of interactions near a Feshbach resonance. Over a large region of parameters
the pairing instability is dominated by finite momentum pairing, suggesting the
possibility of observing FFLO-like states in the unstable initial dynamics.
Long-wavelength density instabilities are found on the BCS side of the
resonance, and are interpreted as a precursor of the phase separation expected
at equilibrium. On the BEC side of the resonance, the pairing instability is
present for scattering lengths that are larger than a critical value that is
only weakly dependent on population imbalance and always smaller than the
scattering length at which the Stoner-like spin instability occurs.",1201.2972v1
2012-05-17,A new Skyrme interaction with improved spin-isospin properties,"A correct determination of the spin-isospin properties of the nuclear
effective interaction should lead, among other improvements, to an accurate
description of the Gamow-Teller Resonance (GTR). These nuclear excitations
impact on a variety of physical processes: from the response in charge-exchange
reactions of nuclei naturally present in the Earth, to the description of the
stellar nucleosynthesis, and of the pre-supernova explosion core-collapse
evolution of massive stars in the Universe. A reliable description of the GTR
provides also stringent tests for neutrinoless double-$\beta$ decay
calculations. We present a new Skyrme interaction as accurate as previous
forces in the description of finite nuclei and of uniform matter properties
around saturation density, and that account well for the GTR in ${}^{48}$Ca,
${}^{90}$Zr and ${}^{208}$Pb, the Isobaric Analog Resonance and the Spin Dipole
Resonance in ${}^{90}$Zr and ${}^{208}$Pb.",1205.3958v2
2012-07-13,Magnetic moments of the low-lying {1/2}^- octet baryon resonances,"The magnetic moments of the negative parity octet resonances with spin {1/2}:
$N^*$(1535), $N^*$(1650), $\Sigma^*$(1620), and $\Xi^*$(1690) have been
calculated within the framework of the chiral constituent quark model. In this
approach, the presence of the polarized $q\bar{q}$ pairs (or the meson cloud,
in other words) is considered by using the Lagrangian for Goldstone boson
emission from the constituent quarks. Further, the explicit contributions
coming from the spin and orbital angular momentum, including the effects of the
configurations mixing between the states with different spins, are obtained.
The motivation for these calculations comes from the recent interest in
experimental measurement of the magnetic moment of the ${S_{11}(1535)}$
resonance and of similar calculations being done within lattice quantum
chromodynamics approaches. Our results can be compared with those expected to
come from these sources.",1207.3311v2
2012-10-01,Resonant addressing and manipulation of silicon vacancy qubits in silicon carbide,"Several systems in the solid state have been suggested as promising
candidates for spin-based quantum information processing. In spite of
significant progress during the last decade, there is a search for new systems
with higher potential [D. DiVincenzo, Nature Mat. 9, 468 (2010)]. We report
that silicon vacancy defects in silicon carbide comprise the technological
advantages of semiconductor quantum dots and the unique spin properties of the
nitrogen-vacancy defects in diamond. Similar to atoms, the silicon vacancy
qubits can be controlled under the double radio-optical resonance conditions,
allowing for their selective addressing and manipulation. Furthermore, we
reveal their long spin memory using pulsed magnetic resonance technique. All
these results make silicon vacancy defects in silicon carbide very attractive
for quantum applications.",1210.0505v1
2012-11-26,Complex Orbital State Stabilized by Strong Spin-Orbit Coupling in a Metallic Iridium Oxide IrO$_{2}$,"Resonant x-ray diffraction experiments were performed for the metallic
iridium oxide IrO$_{2}$. We observed anisotropic tensor of susceptibility (ATS)
scattering, the spectrum of which shows a sharp contrast between the $L_{3}$
and $L_{2}$ edges. At the $L_{3}$ edge, resonance excitations were clearly
observed from the core 2$p$ orbitals to both the 5$d$ $t_{2g}$ and $e_{g}$
orbitals. In contrast, the resonance mode associated with 5$d$ $t_{2g}$
orbitals was indiscernible at the $L_{2}$ edge. This contrasting behavior
indicates that Ir 5$d$ $t_{2g}$ orbitals are fairly close to the $J_{\rm eff}$
= 1/2 state due to the strong spin--orbit coupling in 5$d$ transition metal
ions, as in the Mott insulator Sr$_{2}$IrO$_{4}$. Our results clearly
demonstrate that ATS scattering is a useful probe for investigating complex
orbital states in a metallic state. Such states induce novel phenomena such as
the spin Hall effect.",1211.5855v1
2013-02-04,Magnetic order and low-energy excitations in the quasi-one-dimensional antiferromagnet CuSe$_2$O$_5$ with staggered fields,"Ground state and low-energy excitations of the quasi-one-dimensional
antiferromagnet CuSe$_2$O$_5$ were experimentally studied using bulk
magnetization, neutron diffraction, muon spin relaxation and antiferromagnetic
resonance measurements. Finite interchain interactions promote long-range
antiferromagnetic order below $T_N=17$ K. The derived spin canted structure is
characterized by the magnetic propagation vector $\mathbf{k}=(1, 0, 0)$ and the
reduced magnetic moment $\bm{m}=[0.13(7), 0.50(1), 0.00(8)]\mu_B$. The values
of the magnetic anisotropies determined from the field and angular dependencies
of the antiferromagnetic resonance comply well with a previous electron
paramagnetic resonance study and correctly account for the observed magnetic
ground state and spin-flop transition.",1302.0719v2
2013-03-09,Radio-frequency spectroscopy of a strongly interacting spin-orbit coupled Fermi gas,"We investigate experimentally and theoretically radio-frequency spectroscopy
and pairing of a spin-orbit-coupled Fermi gas of $^{40}$K atoms near a Feshbach
resonance at $B_{0}=202.2$ G. Experimentally, the integrated spectroscopy is
measured, showing characteristic blue and red shifts in the atomic and
molecular responses, respectively, with increasing spin-orbit coupling.
Theoretically, a smooth transition from atomic to molecular responses in the
momentum-resolved spectroscopy is predicted, with a clear signature of
anisotropic pairing at and below resonance. Our many-body prediction agrees
qualitatively well with the observed spectroscopy near the Feshbach resonance.",1303.2212v1
2013-05-08,Higgs Spin Determination in the WW channel and beyond,"After the discovery of the 126 GeV resonance at the LHC, the determination of
its features, including its spin, is a very important ongoing task. In order to
distinguish the two most likely spin hypotheses, spin-0 or spin-2, we study the
phenomenology of a light Higgs-like spin-2 resonance produced in different
gluon-fusion and vector-boson-fusion processes at the LHC. Starting from an
effective model for the interaction of a spin-2 particle with the SM gauge
bosons, we calculate cross sections and differential distributions within the
Monte Carlo program Vbfnlo. We find that with specific model parameters such a
spin-2 resonance can mimic SM Higgs rates and transverse-momentum distributions
in $\gamma \gamma$, $WW$ and $ZZ$ decays, whereas several distributions allow
to separate spin-2 from spin-0, independently of the spin-2 model parameters.",1305.1883v1
2013-05-19,Transition-metal distribution in kagome antiferromagnet CoCu3(OH)6Cl2 revealed by resonant x-ray diffraction,"The distribution of chemically similar transition-metal ions is a fundamental
issue in the study of herbertsmithite-type kagome antiferromagnets. Using
synchrotron radiation, we have performed resonant powder x-ray diffractions on
newly synthesized CoCu3(OH)6Cl2, which provide an exact distribution of
transition-metal ions in the frustrated antiferromagnet. Both magnetic
susceptibility and specific heat measurements are quantitatively consistent
with the occupation fractions determined by resonant x-ray diffraction. The
distribution of transition-metal ions and residual magnetic entropy suggest a
novel low temperature (T < 4 K) magnetism, where the interlayer triangular
spins undergo a spin-glass freezing while the kagome spins still keep highly
frustrated.",1305.4356v1
2014-04-14,Neutron Resonance Spin Flippers: Static Coils Manufactured by Electrical Discharge Machining,"Radiofrequency spin flippers (RFSF) are key elements of Neutron Resonance
Spin Echo (NRSE) spectrometers, which allow performing controlled manipulations
of the beam polarization. We report on the design and test of a new type of
RFSF which originality lies in the new manufacturing technique for the static
coil. The largely automated procedure ensures reproducible construction as well
as an excellent homogeneity of the neutron magnetic resonance condition over
the coil volume. Two salient features of this concept are the large neutron
window and the closure of the coil by a $\mu$-metal yoke which prevents field
leakage outside of the coil volume. These properties are essential for working
with large beams and enable new applications with coils tilted with respect to
the beam axis such as neutron Larmor diffraction or the study of dispersive
excitations by inelastic NRSE.",1404.3613v2
2014-07-09,Double-finger-gate controlled spin-resolved resonant quantum transport in the presence of a Rashba-Zeeman gap,"We investigate double finger gate (DFG) controlled spin-resolved resonant
transport properties in an n-type quantum channel with a Rashba-Zeeman (RZ)
subband energy gap. By appropriately tuning the DFG in the strong Rashba
coupling regime, resonant state structures in conductance can be found that is
sensitive to the length of the DFG system. Furthermore, a hole-like bound state
feature below the RZ gap and an electron-like quasi-bound state feature at the
threshold of the upper spin branch can be found that is insensitive to the
length of the DFG system.",1407.2369v2
2014-11-12,Quantum magnetism and topological ordering via enhanced Rydberg-dressing near Förster-resonances,"We devise a cold-atom approach to realizing a broad range of bi-linear
quantum magnets. Our scheme is based on off-resonant single-photon excitation
of Rydberg $P$-states (Rydberg-dressing), whose strong interactions are shown
to yield controllable XYZ-interactions between effective spins, represented by
different atomic ground states. The distinctive features of F\""orster-resonant
Rydberg atom interactions are exploited to enhance the effectiveness of
Rydberg-dressing and, thereby, yield large spin-interactions that greatly
exceed corresponding decoherence rates. We illustrate the concept on a spin-1
chain implemented with cold Rubidium atoms, and demonstrate that this permits
the dynamical preparation of topological magnetic phases. Generally, the
described approach provides a viable route to exploring quantum magnetism with
dynamically tuneable (an)isotropic interactions as well as variable space- and
spin-dimensions in cold-atom experiments.",1411.3118v2
2015-02-25,All-optical thermometry and the thermal properties of the optically detected spin resonances of the NV center in nano-diamond,"The negatively-charged nitrogen-vacancy (NV) center in diamond is at the
frontier of quantum nano-metrology and bio-sensing. Recent attention has
focused on the application of high-sensitivity thermometry using the spin
resonances of NV centers in nano-diamond to sub-cellular biological and
biomedical research. Here, we report a comprehensive investigation of the
thermal properties of the center's spin resonances and demonstrate an alternate
all-optical NV thermometry technique that exploits the temperature dependence
of the center's optical Debye-Waller factor.",1502.07035v1
2015-04-09,Low-field microwave absorption and magnetoresistance in iron nanostructures grown by electrodeposition on n-type lightly-doped silicon substrates,"In this study we investigate magnetic properties, surface morphology and
crystal structure in iron nanoclusters electrodeposited on lightly-doped (100)
n-type silicon substrates. Our goal is to investigate the spin injection and
detection in the Fe/Si lateral structures. The samples obtained under electric
percolation were characterized by magnetoresistive and magnetic resonance
measurements with cycling the sweeping applied field in order to understand the
spin dynamics in the as-produced samples. The observed hysteresis in the
magnetic resonance spectra, plus the presence of a broad peak in the
non-saturated regime confirming the low field microwave absorption (LFMA), were
correlated to the peaks and slopes found in the magnetoresistance curves. The
results suggest long range spin injection and detection in low resistive
silicon and the magnetic resonance technique is herein introduced as a
promising tool for analysis of electric contactless magnetoresistive samples.",1504.02508v1
2015-06-09,Spin dynamics in a Curie-switch,"Ferromagnetic resonance properties of F$_1$/f/F$_2$/AF multilayers, where
weakly ferromagnetic spacer f is sandwiched between strongly ferromagnetic
layers F$_1$ and F$_2$, with F$_1$ being magnetically soft and F$_2$ -
magnetically hard due to exchange pinning to antiferromagnetic layer AF, are
investigated. Spacer-mediated exchange coupling is shown to strongly affect the
resonance fields of both F$_1$ and F$_2$ layers. Our theoretical calculations
as well as measurements show that the key magnetic parameters of the spacer,
which govern the ferromagnetic resonance in F$_1$/f/F$_2$/AF, are the magnetic
exchange length ($\Lambda$), effective saturation magnetization at $T=0$
$(m_0)$, and effective Curie temperature ($T_{\text{C}}^{\text{eff}}$). The
values of these key parameters are deduced from the experimental data for
multilayers with f = Ni$_x$Cu$_{100-x}$, for the key ranges in Ni-concentration
($x=54\div70$ at. %) and spacer thickness ($d=3\div 6$ nm). The results
obtained provide a deeper insight into thermally-controlled spin precession and
switching in magnetic nanostructures, with potential applications in spin-based
oscillators and memory devices.",1506.02928v1
2015-07-14,High cooperativity coupling between a phosphorus donor spin ensemble and a superconducting microwave resonator,"We investigate the coupling of an ensemble of phosphorus donors in an
isotopically purified $^{28}$Si host lattice interacting with a superconducting
coplanar waveguide resonator. The microwave transmission spectrum of the
resonator shows a normal mode splitting characteristic for high cooperativity.
The evaluated collective coupling strength $g_{\mathrm{eff}}$ is of the same
order as the loss rate of the spin system $\gamma$, indicating the onset of
strong coupling. We develop a statistical model to describe the influence of
temperature on the coupling strength from $50\,\mathrm{mK}$ to
$3.5\,\mathrm{K}$ and find a scaling of the coupling strength with the square
root of the number of thermally polarized spins.",1507.03739v2
2015-09-04,Collective spin resonance excitation in the gapped itinerant multipole hidden order phase of URu2Si2,"An attractive proposal for the hidden order (HO) in the heavy electron
compound URu2Si2 is an itinerant multipole order of high rank. It is due to the
pairing of electrons and holes centered on zone center and boundary,
respectively in states that have maximally different total angular momentum
components. Due to the pairing with commensurate zone boundary ordering vector
the translational symmetry is broken and a HO quasiparticle gap opens below the
transition temperature T_HO. Inelastic neutron scattering (INS) has
demonstrated that for T<T_HO the collective magnetic response is dominated by a
sharp spin exciton resonance at the ordering vector Q that is reminiscent of
spin exciton modes found inside the gap of unconventional superconductors and
Kondo insulators. We use an effective two-orbital tight binding model
incorporating the crystalline electric field effect to derive closed
expressions for quasiparticle bands reconstructed by the multipolar pairing
terms. We show that the magnetic response calculated within that model exhibits
the salient features of the resonance found in INS. We also use the calculated
dynamical susceptibility to explain the low temperature NMR relaxation rate.",1509.01458v1
2015-12-11,Proposal for Quantum Sensing Based on Two-Dimensional Dynamical Decoupling: NMR Correlation Spectroscopy of Single Molecules,"Nuclear magnetic resonance (NMR) has enormous applications. Two-dimensional
NMR is an essential technique to characterize correlations between nuclei and,
hence, molecule structures. Towards the ultimate goal of single-molecule NMR,
dynamical-decoupling- (DD) enhanced diamond quantum sensing enables the
detection of single nuclear spins and nanoscale NMR. However, there is still
the lack of a standard method in DD-based quantum sensing to characterize
correlations between nuclear spins in single molecules. Here we present a
scheme of two-dimensional DD-based quantum sensing, as a universal method for
correlation spectroscopy of single molecules. We design two-dimensional DD
sequences composed of two sets of periodic DD sequences with different periods,
which can be independently set to match two different transition frequencies
for resonant DD. We find that under the resonant DD condition the sensor
coherence patterns, as functions of the two independent pulse numbers of DD
subsequences, can fully determine different types of correlations between
nuclear spin transitions. This work offers a systematic approach to correlation
spectroscopy for single-molecule NMR.",1512.03548v3
2016-02-04,High density NV sensing surface created via He^(+) ion implantation of (12)^C diamond,"We present a promising method for creating high-density ensembles of
nitrogen-vacancy centers with narrow spin-resonances for high-sensitivity
magnetic imaging. Practically, narrow spin-resonance linewidths substantially
reduce the optical and RF power requirements for ensemble-based sensing. The
method combines isotope purified diamond growth, in situ nitrogen doping, and
helium ion implantation to realize a 100 nm-thick sensing surface. The obtained
10^(17) cm^(-3) nitrogen-vacancy density is only a factor of 10 less than the
highest densities reported to date, with an observed spin resonance linewidth
over 10 times more narrow. The 200 kHz linewidth is most likely limited by
dipolar broadening indicating even further reduction of the linewidth is
desirable and possible.",1602.01534v1
2016-02-26,On a possibility of a consistent interpretation of diboson excesses at LHC,"Recently reported diboson and diphoton excesses at LHC are interpreted to be
connected with heavy $WW$ zero spin resonances. The resonances appears due to
the wouldbe anomalous triple interaction of the weak bosons, which is defined
by well-known coupling constant $\lambda$. The $2\, TeV$ anomaly tentatively
corresponds to weak isotopic spin 2 scalar state and the $\gamma\gamma\,\,750\,
GeV$ anomaly corresponds to weak isotopic spin 0 pseudoscalar state. We obtain
estimates for the effect, which qualitatively agree with ATLAS data. Effects
are predicted in a production of $W^+ W^-, (Z,\gamma) (Z,\gamma)$ via resonance
$X_{PS}$ with $M_{PS} \simeq 750\,GeV$, which could be reliably checked at the
upgraded LHC at $\sqrt{s}\,=\,13\, TeV$. In the framework of an approach to the
spontaneous generation of the triple anomalous interaction its coupling
constant is estimated to be $\lambda = -\,0.02\pm 0.005$ in an agreement with
existing restrictions. Specific predictions of the hypothesis are significant
effects in decay channels $X_{PS} \to \gamma\,l^+\,l^-\,, X_{PS} \to
l^+\,l^-\,\,l^+\,l^-\,(l = e,\,\mu)$.",1602.08293v2
2016-04-06,Towards achieving strong coupling in 3D-cavity with solid state spin resonance,"We investigate the microwave magnetic field confinement in several microwave
3D-cavities, using 3D finite-element analysis to determine the best design and
achieve strong coupling between microwave resonant cavity photons and solid
state spins. Specifically, we design cavities for achieving strong coupling of
electromagnetic modes with an ensemble of nitrogen vacancy (NV) defects in
diamond. We report here a novel and practical cavity design with a magnetic
filling factor of up to 4 times (2 times higher collective coupling) than
previously achieved using 1D superconducting cavities with small mode volume.
In addition, we show that by using a double-split resonator cavity, it is
possible to achieve up to 200 times better cooperative factor than the
currently demonstrated with NV in diamond. These designs open up further
opportunities for studying strong and ultra-strong coupling effects on spins in
solids using alternative systems with a wider range of design parameters.",1604.01516v1
2016-05-15,Fokker-Planck formalism in magnetic resonance simulations,"This paper presents an overview of the Fokker-Planck formalism for
non-biological magnetic resonance simulations, describes its existing
applications and proposes some novel ones. The most attractive feature of
Fokker-Planck theory compared to the commonly used Liouville - von Neumann
equation is that, for all relevant types of spatial dynamics (spinning,
diffusion, flow, etc.), the corresponding Fokker-Planck Hamiltonian is
time-independent. Many difficult NMR, EPR and MRI simulation problems (multiple
rotation NMR, ultrafast NMR, gradient-based zero-quantum filters, diffusion and
flow NMR, off-resonance soft microwave pulses in EPR, spin-spin coupling
effects in MRI, etc.) are simplified significantly in Fokker-Planck space. The
paper also summarises the author's experiences with writing and using the
corresponding modules of the Spinach library - the methods described below have
enabled a large variety of simulations previously considered too complicated
for routine practical use.",1605.05243v2
2016-09-05,Proposal for detection of a single electron spin in a microwave resonator,"We propose a method for detecting the presence of a single spin in a crystal
by coupling it to a high-quality factor superconducting planar resonator. By
confining the microwave field in a constriction of nanometric dimensions, the
coupling constant can be as high as $5-10$\,kHz. This coupling affects the
amplitude of the field emitted by the resonator, and the integrated homodyne
signal allows detection of a single spin with unit signal-to-noise ratio within
few milliseconds. We further show that a stochastic master equation approach
and a Bayesian analysis of the full time dependent homodyne signal improves
this figure by $\sim 30\%$ for typical parameters.",1609.01132v2
2017-12-13,Experimental demonstration of two-photon magnetic resonances in a single-spin-system of a solid,"While the manipulation of quantum systems is significantly developed so far,
achieving a single-source multi-use system for quantum-information processing
and networks is still challenging. A virtual state, a so-called ``dressed
state,"" is a potential host for quantum hybridizations of quantum physical
systems with various operational ranges. We present an experimental
demonstration of a dressed state generated by two-photon magnetic resonances
using a single spin in a single nitrogen-vacancy center in diamond. The
two-photon magnetic resonances occur under the application of microwave and
radio-frequency fields, with different operational ranges. The experimental
results reveal the behavior of two-photon magnetic transitions in a single
defect spin in a solid, thus presenting new potential quantum and
semi-classical hybrid systems with different operational ranges using
superconductivity and spintronics devices.",1712.04615v3
2018-09-28,All-Optical Spin Locking in Alkali-Vapor Magnetometers,"The nonlinear Zeeman effect can induce splittings and asymmetries of
magnetic-resonance lines in the geophysical magnetic-field range. We
demonstrate a scheme to suppress the nonlinear Zeeman effect all optically
based on spin locking. Spin locking is achieved with an effective oscillating
magnetic field provided by the AC Stark-shift of an intensity-modulated and
polarization-modulated laser beam. This results in the collapse of the
multi-component asymmetric magnetic-resonance line with about 100 Hz width in
the Earth-field range into a peak with a central component width of 25Hz. The
technique is expected to be broadly applicable in practical magnetometry,
potentially boosting the sensitivity and accuracy of Earth-surveying
magnetometers by increasing the magnetic-resonance amplitude and decreasing its
width. Advantage of an all-optical approach is the absence of cross-talk
between nearby sensors when these are used in a gradiometric or in an array
arrangement.",1809.10906v1
2017-05-25,Suppression of 1/f noise in solid state quantum devices by surface spin desorption,"Noise and decoherence due to spurious two-level systems (TLS) located at
material interfaces is a long-standing issue in solid state quantum
technologies. Efforts to mitigate the effects of TLS have been hampered by a
lack of surface analysis tools sensitive enough to identify their chemical and
physical nature. Here we measure the dielectric loss, frequency noise and
electron spin resonance (ESR) spectrum in superconducting resonators and
demonstrate that desorption of surface spins is accompanied by an almost
tenfold reduction in the frequency noise. We provide experimental evidence that
simultaneously reveals the chemical signatures of adsorbed magnetic moments and
demonstrates their coupling via the electric-field degree of freedom to the
resonator, causing dielectric (charge) noise in solid state quantum devices.",1705.09158v1
2018-07-22,Quantitative nanoscale MRI with a wide field of view,"Magnetic spin resonance is a key non-invasive sensing and imaging technique
across the life-, material- and fundamental sciences with further medical and
commercial applications. Recent advances using paramagnetic color centers
enable magnetic resonance down on the nanoscale, and sensitivity to single
molecules is in sight. Ensemble sensing and wide field imaging improve
sensitivity and acquisition speed, but may suffer from inhomogeneous spin
control fields, produced by e.g. microstructures in integrated devices, and
limited spatial resolution. Here we demonstrate multiplexed nuclear magnetic
resonance imaging using diamond nitrogen-vacancy centers in such adverse
conditions. We image thin films of calcium fluoride down to $1.2\,\mathrm{nm}$
in thickness with a spatial resolution of $250\,\mathrm{nm}$. This corresponds
to a net moment of about 140 nuclear spins within the sensing radius of a given
NV in the ensemble.",1807.08343v1
2016-03-02,Electric-Field-Induced Spin Resonance in Antiferromagnetic Insulators: Inverse Process of the Dynamical Chiral Magnetic Effect,"We propose a realization of the electric-field-induced antiferromagnetic
resonance. We consider three-dimensional antiferromagnetic insulators with
spin-orbit coupling characterized by the existence of a topological term called
the $\theta$ term. By solving the Landau-Lifshitz-Gilbert equation in the
presence of the $\theta$ term, we show that, in contrast to conventional
methods using ac magnetic fields, the antiferromagnetic resonance state is
realized by ac electric fields along with static magnetic fields. This
mechanism can be understood as the inverse process of the dynamical chiral
magnetic effect, an alternating current generation by magnetic fields. In other
words, we propose a way to electrically induce the dynamical axion field in
condensed matter. We discuss a possible experiment to observe our proposal,
which utilizes the spin pumping from the antiferromagnetic insulator into a
heavy metal contact.",1603.00614v3
2016-12-21,Augury of Darkness: The Low-Mass Dark Z' Portal,"Dirac fermion dark matter models with heavy $Z^{\prime}$ mediators are
subject to stringent constraints from spin-independent direct searches and from
LHC bounds, cornering them to live near the $Z^{\prime}$ resonance. Such
constraints can be relaxed, however, by turning off the vector coupling to
Standard Model fermions, thus weakening direct detection bounds, or by
resorting to light $Z^{\prime}$ masses, below the Z pole, to escape heavy
resonance searches at the LHC. In this work we investigate both cases, as well
as the applicability of our findings to Majorana dark matter. We derive
collider bounds for light $Z^{\prime}$ gauge bosons using the $CL_S$ method,
spin-dependent scattering limits, as well as the spin-independent scattering
rate arising from the evolution of couplings between the energy scale of the
mediator mass and the nuclear energy scale, and indirect detection limits. We
show that such scenarios are still rather constrained by data, and that near
resonance they could accommodate the gamma-ray GeV excess in the Galactic
center.",1612.07282v2
2017-10-09,Photoassociation spectroscopy of ultracold $^{173}$Yb atoms near the intercombination line,"We report on photoassociation (PA) spectroscopy of a degenerate Fermi gas of
$^{173}$Yb atoms near the dissociation limit of the spin-forbidden
${^1}S_0-{^3}P_1$ intercombination transition. An atom-loss spectrum is
measured from a trapped sample for a spectral range down to $-1$~GHz with
respect to the $f=5/2 \rightarrow f^\prime=7/2$ atomic resonance. The spectrum
shows eighty PA resonances, revealing the high nuclear spin nature of the
system. We investigate the Zeeman effect on the spectrum near a detuning of
$-0.8$~GHz, where we examine the quantum numbers of the Zeeman levels using
various two-component spin mixture samples. Finally, we measure the atom loss
rate under PA light for several pronounced PA resonances.",1710.03072v1
2020-09-20,Floquet dynamical phase transition and entanglement spectrum,"We explore both pure and mixed states Floquet dynamical quantum phase
transitions (FDQFTs) in the one-dimensional p-wave superconductor with a
time-driven pairing phase. In the Fourier space, the model is recast to the
non-interacting quasi-spins subjected to a time-dependent effective magnetic
field. We show that FDQFTs occur within a range of driving frequency without
resorting to any quenches. Moreover, FDQFTs appear in the region where
quasi-spins are in the resonance regime. In the resonance regime, the
population completely cycles the population between the spin down and up
states. Additionally, we study the conditions for the appearance of FDQFTs
using the entanglement spectrum and purity entanglement measure. Our results
imply that the entanglement spectrum can truly capture the resonance regime
where FDQFTs occur. Particularly, the dynamical topological region results in
the degeneracy of the entanglement spectrum. It is shown that the boundary of
the driven frequency range, over which the system reveals FDQFTs, signaled by
the purity entanglement measure.",2009.09484v2
2021-04-09,Identification of silicon vacancy-related electron paramagnetic resonance centers in 4H SiC,"The negatively charged silicon vacancy [V$_\text{Si}(-)$] in silicon carbide
(SiC) is a paramagnetic and optically active defect in hexagonal SiC.
V$_\text{Si}(-)$ defect possesses $S = 3/2$ spin with long spin coherence time
and can be optically manipulated even at room temperature. Recently, electron
spin resonance signals have been observed besides the signals associated with
the V$_\text{Si}(-)$ defects in the 4H polytype of SiC. The corresponding
centers share akin properties to those of the V$_\text{Si}(-)$ defects and thus
they may be promising candidates for quantum technology applications. However,
the exact origin of the new signals is unknown. In this paper we report
V$_\text{Si}(-)$-related pair defect models as possible candidates for the
unknown centers. We determine the corresponding electronic structures and
magneto-optical properties as obtained by density functional theory (DFT)
calculations. We propose models for the recently observed electron paramagnetic
resonance centers with predicting their optical signals for identification in
future experiments.",2104.04292v1
2019-01-29,Low-impedance superconducting microwave resonators for strong coupling to small magnetic mode volumes,"Recent experiments on strongly coupled microwave and ferromagnetic resonance
modes have focused on large volume bulk crystals such as yttrium iron garnet,
typically of millimeter-scale dimensions. We extend these experiments to lower
volumes of magnetic material by exploiting low-impedance lumped-element
microwave resonators. The low impedance equates to a smaller magnetic mode
volume, which allows us to couple to a smaller number of spins in the
ferromagnet. Compared to previous experiments, we reduce the number of
participating spins by two orders of magnitude, while maintaining the strength
of the coupling rate. Strongly coupled devices with small volumes of magnetic
material may allow the use of spin orbit torques, which require high current
densities incompatible with existing structures.",1901.10395v1
2019-08-14,Spin State Dynamics in a Bichromatic Microwave Field: Role of Bright and Dark States in coupling with Reservoir,"Driving an open spin system by two strong, nearly degenerate fields enables
addressing populations of individual spin states, characterisation of their
interaction with thermal bath, and measurements of their relaxation/decoherence
rates. With such addressing we observe nested magnetic resonances having
nontrivial dependence on microwave field intensity: while the width of one of
the resonances undergoes a strong power broadening, the other one exhibits a
peculiar field-induced stabilization. We also observe light-induced narrowing
of such composite resonances. The observations are explained by the dynamics of
bright and dark superposition states and their interaction with reservoir.",1908.05205v2
2020-07-07,Current Fluctuations Driven by Ferromagnetic and Antiferromagnetic Resonance,"We consider electron transport in ferromagnets or antiferromagnets sandwiched
between metals. When spins in the magnetic materials precess, they emit
currents into the surrounding conductors. Generally, adiabatic pumping in
mesoscopic systems also enhances current fluctuations. We generalize the
description of current fluctuations driven by spin dynamics in three ways using
scattering theory. First, our theory describes a general junction with any
given electron scattering properties. Second, we consider antiferromagnets as
well as ferromagnets. Third, we treat multiterminal devices. Using shot
noise-induced current fluctuations to reveal antiferromagnetic resonance
appears to be easier than using them to reveal ferromagnetic resonance. The
origin of this result is that the associated energies are much higher as
compared to the thermal energy. The thermal energy governs the Johnson-Nyquist
that is independent of the spin dynamics. We give results for various
junctions, such as ballistic and disordered contacts. Finally, we discuss
experimental consequences.",2007.03257v2
2021-01-22,Opportunities for long-range magnon-mediated entanglement of spin qubits via on- and off-resonant coupling,"The ability to manipulate entanglement between multiple spatially-separated
qubits is essential for quantum information processing. Although
nitrogen-vacancy (NV) centers in diamond provide a promising qubit platform,
developing scalable two-qubit gates remains a well-known challenge. To this
end, magnon-mediated entanglement proposals have attracted attention due to
their long-range spin-coherent propagation. Optimal device geometries and gate
protocols of such schemes, however, have yet to be determined. Here we predict
strong long-distance ($>\mu$m) NV-NV coupling via magnon modes with
cooperativities exceeding unity in ferromagnetic bar and waveguide structures.
Moreover, we explore and compare on-resonant transduction and off-resonant
virtual-magnon exchange protocols, and discuss their suitability for generating
or manipulating entangled states at low temperatures ($T\lesssim 150$ mK) under
realistic experimental conditions. This work will guide future experiments that
aim to entangle spin qubits in solids with magnon excitations.",2101.09220v2
2022-04-23,Theory of inertial spin dynamics in anisotropic ferromagnets,"Recent experimental observation of inertial spin dynamics calls upon holistic
reevaluation of the theoretical framework of magnetic resonance in
ferromagnets. Here, we derive the secular equation of an inertial spin system
in analogy to the ubiquitous Smit-Beljers formalism. We find that the frequency
of precessional ferromagnetic resonances is decreased as compared to
non-inertial case. We also find that the frequency of nutational resonances is
generally increased due to the presence of magnetic anisotropy and applied
magnetic field. We obtain exact solutions of the secular equation and
approximations that employ the terminology of non-inertial theory and thus
allow for convenient estimates of the inertial effects.",2204.11057v2
2022-05-23,Metastable discrete time-crystal resonances in a dissipative central spin system,"We consider the non-equilibrium behavior of a central spin system where the
central spin is periodically reset to its ground state. The quantum mechanical
evolution under this effectively dissipative dynamics is described by a
discrete-time quantum map. Despite its simplicity this problem shows
surprisingly complex dynamical features. In particular, we identify several
metastable time-crystal resonances. Here the system does not relax rapidly to a
stationary state but undergoes long-lived oscillations with a period that is an
integer multiple of the reset period. At these resonances the evolution becomes
restricted to a low-dimensional state space within which the system undergoes a
periodic motion. Generalizing the theory of metastability in open quantum
systems, we develop an effective description for the evolution within this
long-lived metastable subspace and show that in the long-time limit a
non-equilibrium stationary state is approached. Our study links to timely
questions concerning emergent collective behavior in the 'prethermal' stage of
a dissipative quantum many-body evolution and may establish an intriguing link
to the phenomenon of quantum synchronization.",2205.11263v1
2022-07-22,A Digital Alkali Spin Maser,"Self-oscillating atomic magnetometers, in which the precession of atomic
spins in a magnetic field is driven by resonant modulation, offer high
sensitivity and dynamic range. Phase-coherent feedback from the detected signal
to the applied modulation creates a resonant spin maser system, highly
responsive to changes in the background magnetic field. Here we show a system
in which the phase condition for resonant precession is met by digital signal
processing integrated into the maser feedback loop. This system uses a modest
chip-scale laser and mass-produced dual-pass caesium vapour cell and operates
in a 50 microtesla field, making it a suitable technology for portable
measurements of the geophysical magnetic field. We demonstrate a Cramer-Rao
lower bound-limited resolution of 50 fT at 1 s sampling cadence, and a sensor
bandwidth of 10 kHz. This device also represents an important class of atomic
system in which low-latency digital processing forms an integral part of a
coherently-driven quantum system.",2207.11009v1
2022-12-27,Spin resonance induced by a mechanical rotation of a polariton condensate,"We study theoretically the polarization dynamics in a ring-shape bosonic
condensate of exciton-polaritons confined in a rotating trap. The interplay
between the rotating potential and TE-TM splitting of polariton modes offers a
tool of control over the spin state and the angular momentum of the condensate.
Specific selection rules describing the coupling of pseudospin and angular
momentum are formulated. The resonant coupling between states having linear and
circular polarizations leads to the polarization beats. The effect may be seen
as a polariton analogy to the electronic magnetic resonance in the presence of
constant and rotating magnetic fields. Remarkably, spin beats are induced by a
purely mechanical rotation of the condensate.",2212.13478v1
2023-05-31,The Ferris ferromagnetic resonance technique: principles and applications,"Measurements of ferromagnetic resonance (FMR) are pivotal to modern magnetism
and spintronics. Recently, we reported on the Ferris FMR technique, which
relies on large-amplitude modulation of the externally applied magnetic field.
It was shown to benefit from high sensitivity while being broadband. The Ferris
FMR also expanded the resonance linewidth such that the sensitivity to spin
currents was enhanced as well. Eventually, the spin Hall angle ({\theta}_SH)
was measurable even in wafer-level measurements that require low current
densities to reduce the Joule heating. Despite the various advantages, analysis
of the Ferris FMR response is limited to numerical modeling where the linewidth
depends on multiple factors such as the field modulation profile and the
magnetization saturation. Here, we describe in detail the basic principles of
operation of the Ferris FMR and discuss its applicability and engineering
considerations. We demonstrated these principles in a measurement of the
orbital Hall effect taking place in Cu, using an Au layer as the orbital to
spin current converter. This illustrates the potential of the Ferris FMR for
the future development of spintronics technology.",2306.01783v1
2023-08-18,QPOs in compact sources as a non-linear hydrodynamical resonance: Determining spin of compact objects,"Origin of wide varieties of quasi-periodic oscillation (QPO) observed in
compact sources is still not well established. Its frequencies range from mHz
to kHz spanning all compact objects. Are different QPOs, with different
frequencies, originating from different Physics? We propose that the emergence
of QPOs is the result of nonlinear resonance of fundamental modes present in
accretion disks forced by external modes including that of the spin of the
underlying compact object. Depending on the properties of accreting flow, e.g.
its velocity and gradient, resonances, and any mode locking, take place at
different frequencies, exhibiting low to high frequency QPOs. We explicitly
demonstrate the origin of higher frequency QPOs for black holes and neutron
stars by a unified model and outline how the same physics could be responsible
to produce lower frequency QPOs. The model also predicts the spin of black
holes, and constrains the radius of neutron stars and the mass of both.",2308.09759v1
2023-09-08,Microscopic analysis of dipole electric and magnetic strengths in $^{156}$Gd,"The dipole electric ($E1$) and magnetic ($M1$) strengths in strongly deformed
$^{156}$Gd are investigated within a fully self-consistent Quasiparticle Random
Phase Approximation (QRPA) with Skyrme forces SVbas, SLy6 and SG2. We inspect,
on the same theoretical footing, low-lying dipole states and the isovector
giant dipole resonance in $E1$ channel and the orbital scissors resonance as
well as the spin-flip giant resonance (SFGR) in $M1$ channel. Besides, $E1$
toroidal mode and low-energy spin-flip $M1$ excitations are considered. The
deformation splitting and dipole-octupole coupling of electric excitations are
analyzed. The origin of SFGR gross structure, impact of the residual
interaction and interference of orbital and spin contributions to SFGR are
discussed. The effect of the central exchange $\textbf{J}^2$-term from the
Skyrme functional is demonstrated. The calculations show a satisfactory
agreement with available experimental data, except for the recent NRF
measurements of M. Tamkas et al for $M1$ strength at 4-6 MeV, where, in
contradiction with our calculations and previous $(p,p')$ data, almost no $M1$
strength was observed.",2309.04294v2
2010-07-23,Intrinsic selection biases of ground-based gravitational wave searches for high-mass BH-BH mergers,"The next generation of ground-based gravitational wave detectors may detect a
few mergers of comparable-mass M\simeq 100-1000 Msun (""intermediate-mass'', or
IMBH) spinning black holes. Black hole spin is known to have a significant
impact on the orbit, merger signal, and post-merger ringdown of any binary with
non-negligible spin. In particular, the detection volume for spinning binaries
depends significantly on the component black hole spins. We provide a fit to
the single-detector and isotropic-network detection volume versus (total) mass
and arbitrary spin for equal-mass binaries. Our analysis assumes matched
filtering to all significant available waveform power (up to l=6 available for
fitting, but only l<= 4 significant) estimated by an array of 64 numerical
simulations with component spins as large as S_{1,2}/M^2 <= 0.8. We provide a
spin-dependent estimate of our uncertainty, up to S_{1,2}/M^2 <= 1. For the
initial (advanced) LIGO detector, our fits are reliable for
$M\in[100,500]M_\odot$ ($M\in[100,1600]M_\odot$). In the online version of this
article, we also provide fits assuming incomplete information, such as the
neglect of higher-order harmonics. We briefly discuss how a strong selection
bias towards aligned spins influences the interpretation of future
gravitational wave detections of IMBH-IMBH mergers.",1007.4213v2
2013-07-06,Accuracy of gravitational waveform models for observing neutron-star--black-hole binaries in Advanced LIGO,"Gravitational waves radiated by the coalescence of compact-object binaries
containing a neutron star and a black hole are one of the most interesting
sources for the ground-based gravitational-wave observatories Advanced LIGO and
Advanced Virgo. Advanced LIGO will be sensitive to the inspiral of a $1.4\,
M_\odot$ neutron star into a $10\,M_\odot$ black hole to a maximum distance of
$\sim 900$ Mpc. Achieving this sensitivity and extracting the physics imprinted
in observed signals requires accurate modeling of the binary to construct
template waveforms. In a NSBH binary, the black hole may have significant
angular momentum (spin), which affects the phase evolution of the emitted
gravitational waves. We investigate the ability of post-Newtonian (PN)
templates to model the gravitational waves emitted during the inspiral phase of
NSBH binaries. We restrict the black hole's spin to be aligned with the orbital
angular momentum and compare several approximants. We examine restricted
amplitude waveforms that are accurate to 3.5PN order in the orbital dynamics
and complete to 2.5PN order in the spin dynamics. We also consider PN waveforms
with the recently derived 3.5PN spin-orbit and 3PN spin-orbit tail corrections.
We compare these approximants to the effective-one-body model. For all these
models, large disagreements start at low to moderate black hole spins,
particularly for binaries where the spin is anti-aligned with the orbital
angular momentum. We show that this divergence begins in the early inspiral at
$v \sim 0.2$ for $\chi_{BH} \sim 0.4$. PN spin corrections beyond those
currently known will be required for optimal detection searches and to measure
the parameters of neutron star--black hole binaries. While this complicates
searches, the strong dependence of the gravitational-wave signal on the spin
dynamics will make it possible to extract significant astrophysical
information.",1307.1757v2
2018-11-14,"Anisotropic-Exchange Magnets on a Triangular Lattice: Spin Waves, Accidental Degeneracies, and Dual Spin Liquids","We present an extensive overview of the phase diagram, spin-wave excitations,
and finite-temperature transitions of the anisotropic-exchange magnets on an
ideal nearest-neighbor triangular lattice. We investigate transitions between
five principal classical phases of the corresponding model: ferromagnetic,
N\'{e}el, its dual, and the two stripe phases. Transitions are identified by
the spin-wave instabilities and by the Luttinger-Tisza approach. Some of the
transitions are direct and others occur via intermediate phases with more
complicated forms of ordering. In a portion of the N\'{e}el phase, we find
spin-wave instabilities to a long-range spiral-like state. In the stripe
phases, quantum fluctuations are mostly negligible, leaving the ordered moment
nearly saturated even for the $S=1/2$ case. However, for a two-dimensional
surface of the full 3D parameter space, the spin-wave spectrum in one of the
stripe phases exhibits an enigmatic accidental degeneracy manifested by
pseudo-Goldstone modes. As a result, despite the nearly classical ground state,
the ordering transition temperature in a wide region of the phase diagram is
significantly suppressed from the mean-field expectation. We identify this
accidental degeneracy as due to an exact correspondence to an extended
Kitaev-Heisenberg model with emergent symmetries that naturally lead to the
pseudo-Goldstone modes. There are previously studied dualities within the
Kitaev-Heisenberg model on the triangular lattice that are exposed here in a
wider parameter space. One important implication of this correspondence for the
$S=1/2$ case is the existence of a region of the spin-liquid phase that is dual
to the spin-liquid phase discovered recently by us. We complement our studies
by the density-matrix renormalization group of the $S=1/2$ model to confirm
some of the duality relations and to verify the existence of the dual
spin-liquid phase.",1811.05983v4
2023-08-09,Competing itinerant and local spin interactions in kagome metal FeGe,"Two-dimensional kagome metals consisting of corner-sharing triangles offer a
unique platform for studying strong electron correlations and band topology due
to its geometrically frustrated lattice structure. The similar energy scales
between spin, lattice, and electronic degrees of freedom in these systems give
rise to competing quantum phases such as charge density wave (CDW), magnetic
order, and superconductivity. For example, kagome metal FeGe first exhibits
A-type collinear antiferromagnetic (AFM) order at T_N ~ 400 K, then establishes
a CDW phase coupled with AFM ordered moment below T_CDW ~ 100 K, and finally
forms a $c$-axis double cone AFM structure around T_Canting ~ 60 K. Here we use
neutron scattering to demonstrate the presence of gapless incommensurate spin
excitations associated with the double cone AFM structure at temperatures well
above T_Canting and T_CDW that merge into gapped commensurate spin waves from
the A-type AFM order. While commensurate spin waves follow the Bose population
factor and can be well described by a local moment Heisenberg Hamiltonian, the
incommensurate spin excitations first appear below T_N where AFM order is
commensurate, start to deviate from the Bose population factor around T_CDW,
and peaks at T_Canting, consistent with a critical scattering of a second order
magnetic phase transition, as a function of decreasing temperature. By
comparing these results with density functional theory calculations, we
conclude that the incommensurate magnetic structure arises from the nested
Fermi surfaces of itinerant electrons and the formation of a spin density wave
order. The temperature dependence of the incommensurate spin excitations
suggests a coupling between spin density wave and CDW order, likely due to flat
electronic bands near the Fermi level around T_N and associated electron
correlation effects.",2308.04815v1
2009-06-25,Intermediate-statistics spin waves,"In this paper, we show that spin waves, the elementary excitation of the
Heisenberg magnetic system, obey a kind of intermediate statistics with a
finite maximum occupation number n. We construct an operator realization for
the intermediate statistics obeyed by magnons, the quantized spin waves, and
then construct a corresponding intermediate-statistics realization for the
angular momentum algebra in terms of the creation and annihilation operators of
the magnons. In other words, instead of the Holstein-Primakoff representation,
a bosonic representation subject to a constraint on the occupation number, we
present an intermediate-statistics representation with no constraints. In this
realization, the maximum occupation number is naturally embodied in the
commutation relation of creation and annihilation operators, while the
Holstein-Primakoff representation is a bosonic operator relation with an
additional putting-in-by-hand restriction on the occupation number. We deduce
the intermediate-statistics distribution function for magnons. On the basis of
these results, we calculate the dispersion relations for ferromagnetic and
antiferromagnetic spin waves. The relations between the intermediate statistics
that magnons obey and the other two important kinds of intermediate statistics,
Haldane-Wu statistics and the fractional statistics of anyons, are discussed.
We also compare the spectrum of the intermediate-statistics spin wave with the
exact solution of the one-dimensional s = 1/2 Heisenberg model, which is
obtained by the Bethe ansatz method. For ferromagnets, we take the
contributions from the interaction between magnons (the quartic contribution),
the next-to-nearest neighbor interaction, and the dipolar interaction into
account for comparison with the experiment.",0906.4818v1
2013-03-29,Next-to-next-to-leading order spin-orbit effects in the gravitational wave flux and orbital phasing of compact binaries,"We compute the next-to-next-to-leading order spin-orbit contributions in the
total energy flux emitted in gravitational waves by compact binary systems.
Such contributions correspond to the post-Newtonian order 3.5PN for maximally
spinning compact objects. Continuing our recent work on the
next-to-next-to-leading spin-orbit terms at 3.5PN order in the equations of
motion, we obtain the spin-orbit terms in the multipole moments of the compact
binary system up to the same order within the multipolar post-Newtonian wave
generation formalism. Our calculation of the multipole moments is valid for
general orbits and in an arbitrary frame; the moments are then reduced to the
center-of-mass frame and the resulting energy flux is specialized to
quasi-circular orbits. The test-mass limit of our final result for the flux
agrees with the already known Kerr black hole perturbation limit. Furthermore
the various multipole moments of the compact binary reduce in the one-body case
to those of a single boosted Kerr black hole. We briefly discuss the
implications of our result for the gravitational-wave flux in terms of the
binary's phase evolution, and address its importance for the future detection
and parameter estimation of signals in gravitational wave detectors.",1303.7412v2
2013-08-01,Magnetostatic wave analog of integer quantum Hall state in patterned magnetic films,"A magnetostatic spin wave analog of integer quantum Hall (IQH) state is
proposed in realistic patterned ferromagnetic thin films. Due to magnetic shape
anisotropy, magnetic moments in a thin film lie within the plane, while all
spin-wave excitations are fully gapped. Under an out-of-plane magnetic field,
the film acquires a finite magnetization, where some of the gapped magnons
become significantly softened near a saturation field. It is shown that, owing
to a spin-orbit locking nature of the magnetic dipolar interaction, these soft
spin-wave volume-mode bands become chiral volume-mode bands with finite
topological Chern integers. A bulk-edge correspondence in IQH physics suggests
that such volume-mode bands are accompanied by a chiral magnetostatic spin-wave
edge mode. The existence of the edge mode is justified both by micromagnetic
simulations and by band calculations based on a linearized Landau-Lifshitz
equation. Employing intuitive physical arguments, we introduce proper
tight-binding models for these soft volume-mode bands. Based on the
tight-binding models, we further discuss possible applications to other systems
such as magnetic ultrathin films with perpendicular magnetic anisotropy (PMA).",1308.0199v3
2018-07-06,Spin wave modes in a cylindrical nanowire in crossover dipolar-exchange regime,"Nanoscale magnetic systems have been studied extensively in various
geometries, such as wires of different cross-sections, arrays of wires, dots,
rings, etc. Such systems have interesting physical properties and promising
applications in advanced magnetic devices. Uniform magnetic nanowires are the
basic structures which were broadly investigated. However, some of their
dynamical properties, like: (anti)crossing between the spin wave modes and
impact of the magnetic field on spin wave spectrum, still need to be exploited.
We continue this research by investigation of the spin wave dynamics in solid
Ni nanowire of the circular cross-section. We use two approaches:
semi-analytical calculations and numerical computations based on finite element
method. We solve coupled Landau-Lifshitz and Maxwell equations and consider
both magnetostatic and exchange interactions. We identify the dispersion
brunches and its (anti)crossing by plotting the spatial profiles of spin wave
amplitudes and magnetostatic potential. We also check how we can tune the
spectrum of the modes by application of the external magnetic field and how it
affects the modes and their dominating type of interaction.",1807.02580v3
2018-10-15,Multiplexed spin-wave-photon entanglement source using temporal-multimode memories and feedforward-controlled readout,"The sources, which generate atom-photon quantum correlations or entanglement
based on quantum memory, are basic blocks for building quantum repeaters (QRs).
For achieving highly entanglement-generation rates in ensemble-based QRs,
spatial-, temporal- and spectral-multimode memories are needed. The previous
temporal-multimode memories are based on rephrasing mechanisms in
inhomogeneous-broadened media. Here, by applying a train of multi-direction
write pulses into a homogeneous-broadened atomic ensemble to induce
Duan-Lukin-Cirac-Zoller-like Raman processes, we prepare up to 19 pairs of
modes, namely, a spin-wave mode and a photonic time bin. Spin-wave-photon
(i.e., atom-photon) entanglement is probabilistically produced in the mode
pairs. As a proof-in-principle demonstration, we show that the multiplexed
source using all the spin-wave modes and feed-forward-control readout increases
spin-wave-photon entanglement generation rate by a factor of $\sim$18.3,
compared to non-multiplexed source using the individual modes. The measured
Bell parameter for the multiplexed source is $2.30\pm 0.02$ combined with a
memory lifetime of $30\mu s$.",1810.06143v2
2019-03-02,Excitation of unidirectional exchange spin waves by a nanoscale magnetic grating,"Magnon spintronics is a prosperous field that promises beyond-CMOS technology
based on elementary excitations of the magnetic order that act as information
carriers for future computational architectures. Unidirectional propagation of
spin waves is key to the realization of magnonic logic devices. However,
previous efforts to enhance the Damon-Eshbach-type nonreciprocity did not
realize (let alone control) purely unidirectional propagation. Here we
experimentally demonstrate excitations of unidirectional exchange spin waves by
a nanoscale magnetic grating consisting of Co nanowires fabricated on an
ultrathin yttrium iron garnet film. We explain and model the nearly perfect
unidirectional excitation by the chirality of the magneto-dipolar interactions
between the Kittel mode of the nanowires and the exchange spin waves of the
film. Reversal of the magnetic configurations of film and nanowire array from
parallel to antiparallel changes the direction of the excited spin waves. Our
results raise the prospect of a chiral magnonic logic without the need for
fragile surface states.",1903.00638v1
2020-03-06,Quantum-router: Storing and redirecting light at the photon level,"We propose a method for spatially re-routing single photons or light in a
coherent state with small average photon number by purely electronic means,
i.e. without using mechanical devices such as micro-mirror arrays. The method
is based on mapping the quantum state of the incoming light onto a spin-wave in
an atomic ensemble as is done in quantum memories of light. Then the wavevector
of the spin-wave is modified in a controlled way by an applied magnetic field
gradient. Finally, by re-applying the same control beam as for storing, the
signal pulse is released in a new direction that depends on the deflected
wavevector of the spin-wave. We show by numerical simulation that efficiencies
can be achieved for arbitrary deflection angles in the plane that are
comparable with simple photon storage and re-emission in forward direction, and
propose a new method for eliminating the stored momentum as source of
decoherence in the quantum memory. In a reasonable parameter regime, the
re-routing should be achievable on a time-scale on the order of few to
$\sim100$ microseconds, depending on the deflection angle. The shifts in the
wavevector that can be achieved using the Zeeman-effect, with otherwise minimal
changes to the spin-wave, can also be used to complement existing ac-Stark
spin-wave manipulation methods.",2003.03363v3
2020-03-17,Electrical generation and detection of terahertz signal based on spin-wave emission from ferrimagnets,"Terahertz (THz) signals, mainly generated by photonic or electronic
approaches, are being sought for various applications, whereas the development
of magnetic source might be a necessary step to harness the magnetic nature of
electromagnetic radiation. We show that the relativistic effect on the
current-driven domain-wall motion induces THz spin-wave emission in
ferrimagnets. The required current density increases dramatically in materials
with strong exchange interaction and rapidly exceeds 1012 A m-2, leading to the
device breakdown and thus the lack of experimental evidence. By translating the
collective magnetization oscillations into voltage signals, we propose a
three-terminal device for the electrical detection of THz spin wave. Through
material engineering, wide frequency range from 264 GHz to 1.1 THz and uniform
continuous signals with improved output power can be obtained. As a reverse
effect, the spin wave generated in this system is able to move ferrimagnetic
domain wall. Our work provides guidelines for the experimental verification of
THz spin wave, and could stimulate the design of THz spintronic oscillators for
wideband applications as well as the all-magnon spintronic devices.",2003.07750v1
2020-11-23,Fanout of 2 Triangle Shape Spin Wave Logic Gates,"Having multi-output logic gates saves much energy because the same structure
can be used to feed multiple inputs of next stage gates simultaneously. This
paper proposes novel triangle shape fanout of 2 spin wave Majority and XOR
gates; the Majority gate is achieved by phase detection, whereas the XOR gate
is achieved by threshold detection. The proposed logic gates are validated by
means of micromagnetic simulations. Furthermore, the energy and delay are
estimated for the proposed structures and compared with the state-of-the-art
spin wave logic gates, and 16nm and 7nm CMOS. The results demonstrate that the
proposed structures provide energy reduction of 25%-50% in comparison to the
other 2-output spin-wave devices while having the same delay, and energy
reduction between 43x and 0.8x when compared to the 16nm and 7nm CMOS while
having delay overhead between 11x and 40x.",2011.11324v5
2019-01-27,Observation of angle-dependent mode conversion and mode hopping in 2D annular antidot lattice,"We report spin-wave excitations in annular antidot lattice fabricated from 15
nm-thin Ni80Fe20 flm. The nanodots of 170 nm diameters are embedded in the 350
nm (diameter) antidot lattice to form the annular antidot lattice, which is
arranged in a square lattice with edge-to-edge separation of 120 nm. A strong
anisotropy in the spin-wave modes are observed with the change in orientation
angle ({\phi}) of the in-plane bias magnetic field by using Time-resolved
Magneto-optic Kerr microscope. A fattened fourfold rotational symmetry, mode
hopping and mode conversion leading to mode quenching for three prominent
spin-wave modes are observed in this lattice with the variation of the bias
field orientation. Micromagnetic simulations enable us to successfully
reproduce the measured evolution of frequencies with the orientation of bias
magnetic field, as well as to identify the spatial profles of the modes. The
magnetostatic field analysis, suggest the existence of magnetostatic coupling
between the dot and antidot in annular antidot sample. Further local
excitations of some selective spin-wave modes using numerical simulations
showed the anisotropic spin-wave propagation through the lattice.",1901.09324v2
2019-07-25,Excitation and propagation of spin waves in non-uniformly magnetized waveguides,"The characteristics of spin waves in ferromagnetic waveguides with nonuniform
magnetization have been investigated for situations where the shape anisotropy
field of the waveguide is comparable to the external bias field. Spin-wave
generation was realized by the magnetoelastic effect by applying normal and
shear strain components, as well as by the Oersted field emitted by an
inductive antenna. The magnetoelastic excitation field has a nonuniform profile
over the width of the waveguide because of the nonuniform magnetization
orientation, whereas the Oersted field remains uniform. Using micromagnetic
simulations, we indicate that both types of excitation fields generate
quantised width modes with both odd and even mode numbers as well as tilted
phase fronts. We demonstrate that these effects originate from the average
magnetization orientation with respect to the main axes of the magnetic
waveguide. Furthermore, it is indicated that the excitation efficiency of the
second-order mode generally surpasses that of the first-order mode due to their
symmetry. The relative intensity of the excited modes can be controlled by the
strain state as well as by tuning the dimensions of the excitation area.
Finally, we demonstrate that the nonreciprocity of spin-wave radiation due to
the chirality of an Oersted field generated by an inductive antenna is absent
for magnetoelastic spin-wave excitation.",1907.11145v3
2020-10-27,Gravitational waves from mountains in newly born millisecond magnetars,"In this paper we study the spin-evolution and gravitational-wave luminosity
of a newly born millisecond magnetar, formed either after the collapse of a
massive star or after the merger of two neutron stars. In both cases we
consider the effect of fallback accretion, and consider the evolution of the
system due to the different torques acting on the star, namely the spin up
torque due to accretion and spin-down torques due to magnetic dipole radiation,
neutrino emission, and gravitational wave emission linked to the formation of a
`mountain' on the accretion poles. Initially the spin period is mostly affected
by the dipole radiation, but at later times accretion spin the star up rapidly.
We find that a magnetar formed after the collapse of a massive star can accrete
up to 1 M_{\odot} , and survive on the order of 50 s before collapsing to a
black hole. The gravitational wave strain, for an object located at 1 Mpc, is
h_c \sim 10^{-23} at kHz frequencies, making this a potential target for next
generation ground based detectors. A magnetar formed after a binary neutron
star merger, on the other hand, accretes at the most 0.2 M_{\odot}, and emits
gravitational waves with a lower maximum strain of the order of h_c \sim
10^{-24} , but also survives for much longer times, and may possibly be
associated with the X-ray plateau observed in the light curve of a number of
short gamma-ray burst.",2010.15574v2
2021-12-25,Spin-wave-driven skyrmion dynamics in ferrimagnets: Effect of net angular momentum,"Searching for low-power-consuming and high-efficient methods for well
controllable driving of skyrmion motion is one of the most concerned issues for
future spintronic applications, raising high concern with an appreciated choice
of magnetic media and driving scenario. In this work, we propose a novel
scenario of spin wave driven skyrmion motion in a ferrimagnetic (FiM) lattice
with the net angular momentum {\delta}s. We investigate theoretically the
effect of both {\delta}s and the circular polarization of spin wave on the
skyrmion dynamics. It is revealed that the momentum onto the skyrmion imposed
by the excited spin wave can be partitioned into a ferromagnetic term plus an
antiferromagnetic term. The ratio of these two terms and consequently the Hall
angle of skyrmion motion can be formulated as the functions of {\delta}s,
demonstrating the key role of {\delta}s as an effective control-parameter for
the skyrmion motion. Moreover, the spin wave frequency dependent skyrmion
motion is discussed, predicting the frequency enhanced skyrmion Hall motion.
This work thus represents an essential contribution to understand the skyrmion
dynamics in a FiM lattice.",2112.13232v2
2021-12-27,Variational Approach to Quantum Spin Liquid in a Rydberg Atom Simulator,"Recently the Rydberg blockade effect has been utilized to realize quantum
spin liquid on the kagome lattice. Evidence of quantum spin liquid has been
obtained experimentally by directly measuring non-local string order. In this
letter, we report a BCS-type variational wave function study of the spin liquid
state in this model. This wave function is motivated by mapping the Rydberg
blockade model to a lattice gauge theory, where the local gauge conservations
replace the role of constraints from the Rydberg blockade. We determine the
variational parameter from the experimental measurement of the Rydberg atom
population. Then we compare the predictions of this deterministic wave function
with the experimental measurements of non-local string order. Combining the
measurements on both open and closed strings, we extract the fluctuations only
associated with the closed-loop as an indicator of the topological order. The
prediction from our wave function agrees reasonably well with the experimental
data without any fitting parameter. Our variational wave function provides a
simple and intuitive picture of the quantum spin liquid in this system that can
be generalized to various generalizations of the current model.",2112.13688v3
2022-04-12,Generation of highly retrievable atom photon entanglement with a millisecond lifetime via a spatially multiplexed cavity,"Qubit memory that is entangled with photonic qubit is the building block for
long distance quantum repeaters. Cavity enhanced and long lived spin wave
photon entanglement has been demonstrated by applying dual laser beams onto
optical-lattice atoms. However, owing to cross readouts by two beams, retrieval
efficiency of spin wave qubit is decreased by one quarter compared to that of
single mode spin wave at all storage times. Here, by coupling cold atoms to two
modes of a polarization interferometer based cavity, we achieve perfect qubit
retrieval in cavity enhanced and long lived atom photon entanglement. A write
laser beam is applied onto cold atoms, we then create a magnetic field
insensitive spin wave qubit that is entangled with the photonic qubit encoded
onto two arms of the interferometer. The spin wave qubit is retrieved by a read
beam, which avoids the cross readouts. Our experiment demonstrates 540{\mu}s
storage time at 50% intrinsic qubit retrieval efficiency, which is 13.5 times
longer than the best reported result.",2204.05794v2
2022-12-05,Propagating spin-wave spectroscopy in nanometer-thick YIG films at millikelvin temperatures,"Performing propagating spin-wave spectroscopy of thin films at millikelvin
temperatures is the next step towards the realisation of large-scale integrated
magnonic circuits for quantum applications. Here we demonstrate spin-wave
propagation in a $100\,\mathrm{nm}$-thick yttrium-iron-garnet film at the
temperatures down to $45 \,\mathrm{mK}$, using stripline nanoantennas deposited
on YIG surface for the electrical excitation and detection. The clear
transmission characteristics over the distance of $10\,\mu \mathrm{m}$ are
measured and the subtracted spin-wave group velocity and the YIG saturation
magnetisation agree well with the theoretical values. We show that the
gadolinium-gallium-garnet substrate influences the spin-wave propagation
characteristics only for the applied magnetic fields beyond $75\,\mathrm{mT}$,
originating from a GGG magnetisation up to $47 \,\mathrm{kA/m}$ at $45
\,\mathrm{mK}$. Our results show that the developed fabrication and measurement
methodologies enable the realisation of integrated magnonic quantum
nanotechnologies at millikelvin temperatures.",2212.02257v3
2023-05-06,Thermal features of Heisenberg antiferromagnets on edge- versus corner-sharing triangular-based lattices: A message from spin waves,"We construct modified spin-wave thermodynamics for frustrated noncollinear
antiferromagnets for the first time. The well-known modified spin-wave theory
for collinear antiferromagnets diagonalizes a bosonic Hamiltonian subject to
the constraint that the total staggered magnetization be zero. Applying this
scheme as it is to frustrated noncollinear antiferromagnets ends in a poor
thermodynamics, missing the optimal ground state and breaking the local U(1)
rotational symmetry. We find a new double-constraint modification scheme to
overcome this difficulty, which is tuned especially to frustrated spiral
magnets but spontaneously goes back to the standard single-constraint condition
at the onset of a collinear N\'eel-ordered classical ground state.
  We apply this new scheme to triangular-based polyhedral and planar
antiferromagnets with particular interest in a possible contrast between edge-
versus corner-sharing geometries. Under such circumstances that very few
methods are available to calculate finite-temperature properties of frustrated
noncollinear quantum magnets in the thermodynamic limit, our newly developed
modified spin-wave theory predicts that the specific heat of the kagome-lattice
Heisenberg antiferromagnet in the corner-sharing geometry remains having both
mid-temperature broad maximum and low-temperature narrow peak in the
thermodynamic limit, while the specific heat of the triangular-lattice
Heisenberg antiferromagnet in the edge-sharing geometry retains a
low-temperature sharp peak followed by a mid-temperature weak anormaly in the
thermodynamic limit.",2305.03958v1
2024-01-19,Exploration of magnon-magnon coupling in an antidot lattice: The role of non-uniform magnetization texture,"We numerically study the spin wave dynamics in an antidot lattice based on a
Co/Pd multilayer structure with reduced perpendicular magnetic anisotropy at
the edges of the antidots. This structure forms a magnonic crystal with a
periodic antidot pattern and a periodic magnetization configuration consisting
of out-of-plane magnetized bulk and in-plane magnetized rims. Our results show
the different behavior of spin waves in the bulk and in the rims under varying
out-of-plane external magnetic field strength, revealing complex spin-wave
spectra and hybridizations between the modes of these two subsystems. A
particularly strong magnon-magnon coupling, due to exchange interactions, is
found between the fundamental bulk spin-wave mode and the second-order radial
rim modes. However, the dynamical coupling between the spin-wave modes at low
frequencies, involving the first-order radial rim modes, is masked by the
changes in the static magnetization at the bulk-rim interface with magnetic
field changes. The study expands the horizons of magnonic-crystal research by
combining periodic structural patterning and non-collinear magnetization
texture to achieve strong magnon-magnon coupling, highlighting the significant
role of exchange interactions in the coupling.",2401.10540v2
2024-02-05,Understanding voltage-controlled magnetic anisotropy effect for the manipulation of dipolar-dominated propagating spin waves,"Spin waves, known for their ability to propagate without the involvement of
moving charges, hold immense promise for on-chip information transfer and
processing, offering a path toward post-CMOS computing technologies. This study
investigates the potential synergy between propagating Damon-Eshbach spin waves
and voltage-controlled magnetization in the pursuit of environmentally
sustainable computing solutions. Employing micromagnetic simulations, we assess
the feasibility of utilizing spin waves in DE mode in conjunction with
localized voltage-induced alterations in surface anisotropy to enable
low-energy logic operations. Our findings underscore the critical importance of
selecting an optimal excitation frequency and gate width, which significantly
influence the efficiency of the phase shift induced in propagating spin waves.
Notably, we demonstrate that a realistic phase shift of 2.5$\left[ \pi \
\text{mrad}\right]$ can be achieved at a Co(5nm)/MgO material system via the
VCMA effect. Moreover, by tuning the excitation frequency, Co layer thickness,
gate width, and the use of a GdO\textsubscript{x} dielectric, we illustrate the
potential to enhance the phase shift by a factor of 200 when compared to MgO
dielectrics. This research contributes valuable insights towards developing
next-generation computing technologies with reduced energy consumption.",2402.03033v1
2016-08-26,Non-collinear antiferromagnetism of coupled spins and pseudospins in the double perovskite La2CuIrO6,"We report the structural, magnetic and thermodynamic properties of the double
perovskite compound La2CuIrO6 from X-ray, neutron diffraction, neutron
depolarization, dc magnetization, ac susceptibility, specific heat,
muon-spin-relaxation (uSR), electron-spin-resonance (ESR) and nuclear magnetic
resonance (NMR) measurements. Below ~113 K, short-range spin-spin correlations
occur within the Cu2+ sublattice. With decreasing temperature, the Ir4+
sublattice progressively involves in the correlation process. Below T = 74 K,
the magnetic sublattices of Cu (spin s = 1/2) and Ir (pseudospin j = 1/2) in
La2CuIrO6 are strongly coupled and exhibit an antiferromagnetic phase
transition into a non-collinear magnetic structure accompanied by a small
uncompensated transverse moment. A weak anomaly in ac-susceptibility as well as
in the NMR and {\mu}SR spin lattice relaxation rates at 54 K is interpreted as
a cooperative ordering of the transverse moments which is influenced by the
strong spin-orbit coupled 5d ion Ir4+. We argue that the rich magnetic
behaviour observed in La2CuIrO6 is related to complex magnetic interactions
between the strongly correlated spin-only 3d ions with the strongly spin-orbit
coupled 5d transition ions where a combination of the spin-orbit coupling and
the low-symmetry of the crystal lattice plays a special role for the spin
structure in the magnetically ordered state.",1608.07513v2
2001-09-25,Single Spin Dynamics and Decoherence in a Quantum Dot via Charge Transport,"We investigate the spin dynamics of a quantum dot with a spin-1/2 ground
state in the Coulomb blockade regime and in the presence of a magnetic rf field
leading to electron spin resonances (ESR). We show that by coupling the dot to
leads, spin properties on the dot can be accessed via the charge current in the
stationary and non-stationary limit. We present a microscopic derivation of the
current and the master equation of the dot using superoperators, including
contributions to decoherence and energy shifts due to the tunnel coupling. We
give a detailed analysis of sequential and co-tunneling currents, for linearly
and circularly oscillating ESR fields, applied in cw and pulsed mode. We show
that the sequential tunneling current exhibits a spin satellite peak whose
linewidth gives a lower bound on the decoherence time T_2 of the dot-spin.
Similarly, the spin decoherence can be accessed also in the cotunneling regime
via ESR induced spin flips. We show that the conductance ratio of the spin
satellite peak and the conventional peak due to sequential tunneling saturates
at the universal conductance ratio of 0.71 for strong ESR fields. We describe a
double-dot setup which generates spin dependent tunneling and acts as a current
pump (at zero bias), and as a spin inverter which inverts the spin-polarization
of the current. We show that Rabi oscillations of the dot-spin induce coherent
oscillations in the time-dependent current. These oscillations are observable
in the time-averaged current as function of ESR pulse-duration, and they allow
one to access the spin coherence directly in the time domain. We analyze the
measurement and read-out process of the dot-spin via currents in spin-polarized
leads and identify measurement time and efficiency by calculating the counting
statistics, noise, and the Fano factor.",0109470v1
2017-11-21,Determination of spin Hall effect and spin diffusion length of Pt from self-consistent fitting of damping enhancement and inverse spin-orbit torque measurements,"Understanding the evolution of spin-orbit torque (SOT) with increasing
heavy-metal thickness in ferromagnet/normal metal (FM/NM) bilayers is critical
for the development of magnetic memory based on SOT. However, several
experiments have revealed an apparent discrepancy between damping enhancement
and damping-like SOT regarding their dependence on NM thickness. Here, using
linewidth and phase-resolved amplitude analysis of vector network analyzer
ferromagnetic resonance (VNA-FMR) measurements, we simultaneously extract
damping enhancement and both field-like and damping-like inverse SOT in
Ni$_{80}$Fe$_{20}$/Pt bilayers as a function of Pt thickness. By enforcing an
interpretation of the data which satisfies Onsager reciprocity, we find that
both the damping enhancement and damping-like inverse SOT can be described by a
single spin diffusion length ($\approx$ 4 nm), and that we can separate the
spin pumping and spin memory loss (SML) contributions to the total damping.
This analysis indicates that less than 40% of the angular momentum pumped by
FMR through the Ni$_{80}$Fe$_{20}$/Pt interface is transported as spin current
into the Pt. On account of the SML and corresponding reduction in total spin
current available for spin-charge transduction in the Pt, we determine the Pt
spin Hall conductivity ($\sigma_\mathrm{SH} = (2.36 \pm 0.04)\times10^6
\Omega^{-1} \mathrm{m}^{-1}$) and bulk spin Hall angle
($\theta_\mathrm{SH}=0.387 \pm0.008$) to be larger than commonly-cited values.
These results suggest that Pt can be an extremely useful source of SOT if the
FM/NM interface can be engineered to minimize SML. Lastly, we find that
self-consistent fitting of the damping and SOT data is best achieved by a model
with Elliott-Yafet spin relaxation and extrinsic inverse spin Hall effect, such
that both the spin diffusion length and spin Hall conductivity are proportional
to the Pt charge conductivity.",1711.07654v2
2013-02-10,An instability due to the nonlinear coupling of p-modes to g-modes: Implications for coalescing neutron star binaries,"A weakly nonlinear fluid wave propagating within a star can be unstable to
three-wave interactions. The resonant parametric instability is a well-known
form of three-wave interaction in which a primary wave of frequency $\omega_a$
excites a pair of secondary waves of frequency $\omega_b+\omega_c \simeq
\omega_a$. Here we consider a nonresonant form of three-wave interaction in
which a low-frequency primary wave excites a high-frequency p-mode and a
low-frequency g-mode such that $\omega_b+\omega_c >>\omega_a$. We show that a
p-mode can couple so strongly to a g-mode of similar radial wavelength that
this type of interaction is unstable even if the primary wave amplitude is
small. As an application, we analyze the stability of the tide in coalescing
neutron star binaries to p-g mode coupling. We find that the equilibrium tide
and dynamical tide are both p-g unstable at gravitational wave frequencies
f_{gw} > 20 Hz and drive p-g pairs to significant energies on very short
timescales (much less than the orbital decay time). Resonant parametric
coupling to the tide is, by contrast, either stable or drives modes at a much
smaller rate. We do not solve for the saturation of the instability and
therefore cannot say precisely how it influences neutron star binaries.
However, we show that if even a single daughter mode saturates near its wave
breaking amplitude, the p-g instability of the equilibrium tide: (i) induces
significant orbital phase errors ($\Delta \phi$ > 1 radian) that accumulate
primarily at low frequencies (f_{gw} < 50 Hz) and (ii) heats the neutron star
core to T~10^{10} K. Since there are >100 unstable daughters, $\Delta \phi$ and
T are potentially much larger than these values. Tides might therefore
significantly influence the gravitational wave signal and electromagnetic
emission from neutron star binaries at much larger orbital separations than
previously thought.",1302.2292v2
2021-06-06,Resonant and near-resonant internal wave triads for non-uniform stratifications. Part 2: Vertically bounded domain with mild-slope bathymetry,"Weakly nonlinear internal wave-wave interaction is a key mechanism that
cascades energy from large to small scales, leading to ocean turbulence and
mixing. Oceans typically have a non-uniform density stratification profile;
moreover, submarine topography leads to a spatially varying ocean depth ($h$).
Under these conditions and assuming mild-slope bathymetry, we employ
multiple-scale analysis to derive the wave amplitude equations for triadic- and
self-interactions. The waves are assumed to have a slowly (rapidly) varying
amplitude (phase) in space and time. For uniform stratifications, the
horizontal wavenumber ($k$) condition for waves ($1$,$2$,$3$), given by
${k}_{(1,a)}+{k}_{(2,b)}+{k}_{(3,c)}=0$, is unaffected as $h$ is varied, where
$(a,b,c)$ denote the modenumber. Moreover, the nonlinear coupling coefficients
(NLC) are proportional to $1/h^2$, implying that triadic waves grow faster
while travelling up a seamount. For non-uniform stratifications, triads that do
not satisfy the condition $a=b=c$ may not satisfy the horizontal wavenumber
condition as $h$ is varied, and unlike uniform stratification, the NLC may not
decrease (increase) monotonically with increasing (decreasing) $h$. NLC, and
hence wave growth rates for both triads and self-interactions, can also vary
rapidly with $h$. The most unstable daughter wave combination of a triad with a
mode-1 parent wave can also change for relatively small changes in $h$. We also
investigate higher-order self-interactions in the presence of a monochromatic,
small amplitude bathymetry; here the bathymetry behaves as a zero frequency
wave. We derive the amplitude evolution equations and show that higher-order
self-interactions might be a viable mechanism of energy cascade.",2106.03198v3
2024-01-24,Spin Seebeck Effect as a Probe for Majorana Fermions in Kitaev Spin Liquids,"Quantum entanglement in strongly correlated electron systems often leads to
exotic elementary excitations. Quantum spin liquids (QSLs) provide a
paradigmatic example, where the elementary excitations are described by
fractional quasiparticles such as spinons. However, such fractional
quasiparticles behave differently from electrons, making their experimental
identification challenging. Here, we theoretically investigate the spin Seebeck
effect, which is a thermoelectric response via a spin current, as an efficient
probe of the fractional quasiparticles in QSLs, focusing on the Kitaev
honeycomb model. By comprehensive studies using the real-time dynamics, the
perturbation theory, and the linear spin-wave theory based on the tunnel
spin-current theory, we find that the spin current is induced by thermal
gradient in the Kitaev spin liquid, via the low-energy fractional Majorana
excitations. This underscores the ability of Majorana fermions to carry spin
current, despite lacking spin angular momentum. Furthermore, we find that the
induced spin current changes its sign depending on the sign of the Kitaev
interaction, indicating that the Majorana fermions contribute to the spin
current with (up-)down-spin like nature when the exchange coupling is
(anti)ferromagnetic. Thus, in contrast to the negative spin current already
found in a one-dimensional QSL, our finding reveals that the spin Seebeck
effect can exhibit either positive or negative signals, contingent upon the
nature of fractional excitations in the QSLs. We also clarify contrasting
field-angle dependence between the Kitaev spin liquid in the low-field limit
and the high-field ferromagnetic state, which is useful for the experimental
identification. Our finding suggests that the spin Seebeck effect could be used
not only to detect fractional quasiparticles emerging in QSLs but also to
generate and control them.",2401.13175v1
2008-09-02,Wave packet dynamics in a monolayer graphene,"The dynamics of charge particles described by Gaussian wave packet in
monolayer graphene is studied analytically and numerically. We demonstrate that
the shape of wave packet at arbitrary time depends on correlation between the
initial electron amplitudes $\psi_1(\vec r,0)$ and $\psi_2(\vec r,0)$ on the
sublattices $A$ and $B$ correspondingly (i.e. pseudospin polarization). For the
transverse pseudospin polarization the motion of the center of wave packet
occurs in the direction perpendicular to the average momentum $ {\vec
p_0}=\hbar \vec{k_0}$. Moreover, in this case the initial wave packet splits
into two parts moving with opposite velocities along $ {\vec p_0}$. If the
initial direction of pseudospin coincides with average momentum the splitting
is absent and the center of wave packet is displaced at $t>0$ along the same
direction. The results of our calculations show that all types of motion
experience {\it zitterbewegung}. Besides, depending on initial polarization the
velocity of the packet center may have the constant component $v_c=uf(a)$,
where $u\approx 10^8 cm/s$ is the Fermi velocity and $f(a)$ is a function of
the parameter $a=k_0d$ ($d$ is the initial width of wave packet). As a result,
the direction of the packet motion is determined not only by the orientation of
the average momentum, but mainly by the phase difference between the up- and
low- components of the wave functions. Similar peculiarities of the dynamics of
2D electron wave packet connected with initial spin polarization should take
place in the semiconductor quantum well under the influence of the Rashba
spin-orbit coupling.",0809.0367v2
2012-04-04,Similar zone-center gaps in the low-energy spin-wave spectra of NaFeAs and BaFe2As2,"We report results of inelastic-neutron-scattering measurements of low-energy
spin-wave excitations in two structurally distinct families of iron-pnictide
parent compounds: Na(1-{\delta})FeAs and BaFe2As2. Despite their very different
values of the ordered magnetic moment and N\'eel temperatures, T_N, in the
antiferromagnetic state both compounds exhibit similar spin gaps of the order
of 10 meV at the magnetic Brillouin-zone center. The gap opens sharply below
T_N, with no signatures of a precursor gap at temperatures between the
orthorhombic and magnetic phase transitions in Na(1-{\delta})FeAs. We also find
a relatively weak dispersion of the spin-wave gap in BaFe2As2 along the
out-of-plane momentum component, q_z. At the magnetic zone boundary (q_z = 0),
spin excitations in the ordered state persist down to 20 meV, which implies a
much smaller value of the effective out-of-plane exchange interaction, J_c, as
compared to previous estimates based on fitting the high-energy spin-wave
dispersion to a Heisenberg-type model.",1204.0875v2
2013-04-25,Statistical and systematic errors for gravitational-wave inspiral signals: A principal component analysis,"Identifying the source parameters from a gravitational-wave measurement alone
is limited by our ability to discriminate signals from different sources and
the accuracy of the waveform family employed in the search. Here we address
both issues in the framework of an adapted coordinate system that allows for
linear Fisher-matrix type calculations of waveform differences that are both
accurate and computationally very efficient. We investigate statistical errors
by using principal component analysis of the post-Newtonian (PN) expansion
coefficients, which is well conditioned despite the Fisher matrix becoming ill
conditioned for larger numbers of parameters. We identify which combinations of
physical parameters are most effectively measured by gravitational-wave
detectors for systems of neutron stars and black holes with aligned spin. We
confirm the expectation that the dominant parameter of the inspiral waveform is
the chirp mass. The next dominant parameter depends on a combination of the
spin and the symmetric mass ratio. In addition, we can study the systematic
effect of various spin contributions to the PN phasing within the same
parametrization, showing that the inclusion of spin-orbit corrections up to
next-to-leading order, but not necessarily of spin-spin contributions, is
crucial for an accurate inspiral waveform model. This understanding of the
waveform structure throughout the parameter space is important to set up an
efficient search strategy and correctly interpret future gravitational-wave
observations.",1304.7017v2
2016-09-07,Magnonic Interferometric Switch for Multi-Valued Logic Circuits,"We investigated a possible use of the magnonic interferometric switches in
multi-valued logic circuits. The switch is a three-terminal device consisting
of two spin channels where input, control, and output signals are spin waves.
Signal modulation is achieved via the interference between the source and gate
spin waves. We report experimental data on a micrometer scale prototype based
on Y3Fe2(FeO4)3 structure. The output characteristics are measured at different
angles of the bias magnetic field. The On/Off ratio of the prototype exceeds 36
dB at room temperature. Experimental data is complemented by the theoretical
analysis and the results of micro magnetic simulations showing spin wave
propagation in a micrometer size magnetic junction. We also present the results
of numerical modeling illustrating the operation of a nanometer-size switch
consisting of just 20 spins in the source-drain channel. The utilization of
spin wave interference as a switching mechanism makes it possible to build
nanometer-scale logic gates, and minimize energy per operation, which is
limited only by the noise margin. The utilization of phase in addition to
amplitude for information encoding offers an innovative route towards
multi-state logic circuits. We describe possible implementation of the
three-value logic circuits based on the magnonic interferometric switches. The
advantages and shortcomings inherent in interferometric switches are also
discussed.",1609.02217v1
2018-06-09,Mapping out the spin-wave modes of constriction-based spin Hall nano-oscillators in weak in-plane fields,"We experimentally study the auto-oscillating spin-wave modes in
NiFe/$\beta-$W constriction-based spin Hall nano-oscillators as a function of
bias current, in-plane applied field strength, and azimuthal field angle, in
the low-field range of 40-80 mT. We observe two different spin-wave modes: i) a
linear-like mode confined to the minima of the internal field near the edges of
the nanoconstriction, with weak frequency dependencies on the bias current and
the applied field angle, and ii) a second, lower frequency mode that has
significantly higher threshold current and stronger frequency dependencies on
both bias current and the external field angle. Our micromagnetic modeling
qualitatively reproduces the experimental data and reveals that the second mode
is a spin-wave bullet and that the SHNO mode hops between the two modes,
resulting in a substantial increase in linewidths. In contrast to the
linear-like mode, the bullet is localized in the middle of the constriction and
shrinks with increasing bias current. Utilizing intrinsic frequency doubling at
zero field angle we can reach frequencies above 9 GHz in fields as low as 40
mT, which is important for the development of low-field spintronic oscillators
with applications in microwave signal generation and neuromorphic computing.",1806.03473v1
2018-12-17,Spin-adapted selected configuration interaction in a determinant basis,"Selected configuration interaction (SCI) methods, when complemented with a
second-order perturbative correction, provide near full configuration
interaction (FCI) quality energies with only a small fraction of the Slater
determinants of the FCI space. However, a selection criterion based on
determinants alone does not ensure a spin-pure wave function. In other words,
such SCI wave functions are not eigenfunctions of the $S^2$ operator. In many
situations (bond breaking, magnetic system, excited state, etc), having a
spin-adapted wave function is essential for a quantitatively correct
description of the system. Here, we propose an efficient algorithm which, given
an arbitrary determinant space, generates all the missing Slater determinants
allowing one to obtain spin-adapted wave functions while avoiding manipulations
involving configuration state functions. For example, generating all the
possible determinants with 6 spin-up and 6 spin-down electrons in 12 open
shells takes 21 CPU cycles per generated Slater determinant. The selection is
still done with individual determinants, and one can take advantage of the
basis of configuration state functions in the diagonalization of the
Hamiltonian to reduce significantly the memory footprint.",1812.06902v3
2019-01-26,All optical detection of picosecond spin-wave dynamics in two-dimensional annular antidot lattice,"Novel magnetic structures with precisely controlled dimensions and shapes at
the nanoscale have potential applications in spin logic, spintronics and other
spin-based communication devices. We report the fabrication of two-dimensional
bi-structure magnonic crystal in the form of embedded nanodots in a periodic
Ni80Fe20 antidot lattice structure (annular antidot) by focused ion-beam
lithography. The spin-wave spectra of the annular antidot sample,studied for
the first time by a time-resolved magneto-optic Kerr effect microscopy show a
remarkable variation with bias field, which is important for the above device
applications. The optically induced spin-wave spectra show multiple modes in
the frequency range 14.7 GHz to 3.5 GHz due to collective interactions between
the dots and antidots as well as the annular elements within the whole array.
Numerical simulations qualitatively reproduce the experimental results, and
simulated mode profiles reveal the spatial distribution of the spin wave modes
and internal magnetic fields responsible for these observations. It is observed
that the internal field strength increases by about 200 Oe inside each dot
embedded within the hole of annular antidot lattice as compared to pure antidot
lattice and pure dot lattice. The stray field for the annular antidot lattice
is found to be significant (0.8kOe) as opposed to the negligible values of the
same for the pure dot lattice and pure antidot lattice. Our findings open up
new possibilities for development of novel artificial crystals.",1901.09152v1
2020-07-13,Spin Wave Generation via Localized Spin-Orbit Torque in an Antiferromagnet-Topological Insulator Heterostructure,"The spin-orbit torque induced by a topological insulator (TI) is
theoretically examined for spin wave generation in a neighboring
antiferromagnetic thin film. The investigation is based on the micromagnetic
simulation of N\'{e}el vector dynamics and the analysis of transport properties
in the TI. The results clearly illustrate that propagating spin waves can be
achieved in the antiferromagnetic thin-film strip through localized excitation,
traveling over a long distance. The oscillation amplitude gradually decays due
to the non-zero damping as the N\'{e}el vector precesses around the magnetic
easy axis with a fixed frequency. The frequency is also found to be tunable via
the strength of the driving electrical current density. While both the bulk and
the surface states of the TI contribute to induce the effective torque, the
calculation indicates that the surface current plays a dominant role over the
bulk counterpart except in the heavily degenerate cases. Compared to the more
commonly applied heavy metals, the use of a TI can substantially reduce the
threshold current density to overcome the magnetic anisotropy, making it an
efficient choice for spin wave generation. The N\'{e}el vector dynamics in the
nano-oscillator geometry are examined as well.",2007.06663v1
2022-03-31,Gravitational Waves in Einstein-Cartan Theory: On the Effects of Dark Matter Spin Tensor,"This article studies the effects of an arbitrary dark matter spin tensor on
the propagation of gravitational wave amplitude in the context of
Einstein-Cartan theory. We choose to work with an arbitrary spin tensor
because, given our ignorance of the nature of dark matter, it is sensible not
to make further hypotheses on its spin and not to assume any particular model
for its spin tensor (or its vanishing). The analysis focuses on a
\textquotedblleft weak-torsion regime,\textquotedblright\ such that
gravitational wave emission, at leading and subleading orders, does not deviate
from standard General Relativity. We show that, in principle, the background
torsion induced by an eventual dark matter spin component could lead to an
anomalous dampening or amplification of the gravitational wave amplitude, after
going across a long cosmological distance. We assess the importance of this
torsion-induced anomalous amplitude propagation for binary black hole mergers
in a way as model-free as possible in Einstein-Cartan gravity. It is possible
to prove that at its best, for realistic late-universe cosmological scenarios,
the effect is tiny and falls below detection thresholds, even for near-future
interferometers such as LISA. Therefore, detecting this effect may not be
impossible, but it is still beyond our technological capabilities. As a
model-independent result in the Einstein-Cartan context, it also implies that
mergers are robust standard sirens without considering any potential
dark-matter-induced torsional effects.",2204.00090v2
2022-04-26,"Frustrated Antiferromagnetic Triangular Lattice with Dzyaloshinskii-Moriya Interaction: Ground States, Spin Waves, Skyrmion Crystal, Phase Transition","We study in this article a triangular lattice with Heisenberg spins
interacting with each other via an antiferromagnetic exchange interaction $J$
and a Dzyaloshinskii-Moriya (DM) interaction $D$, between nearest-neighbors
(NN). We consider two cases: the first case in which the DM vector $\mathbf D$
is perpendicular to the lattice plane and the second case where it lies in the
plane. A magnetic field $H$ is applied perpendicular to the spin plane in both
cases. The ground state (GS) of this system is calculated by minimizing the
energy using the very fast steepest-descent method in the two cases. In the
case of perpendicular $\mathbf D$ with $H=0$, the GS is periodic. We
analytically determine the GS configuration which is characterized by two
well-defined angles. We calculate the spin-wave spectrum in this case which
shows that for small wave vectors the spin waves are forbidden in the system.
When $H\neq 0$, the GS in the perpendicular $\mathbf D$ case shows no
skyrmions. However, in the case of in-plane $\mathbf D$ with $H\neq 0$, we find
a crystal of skyrmions at $T=0$ composed of three interpenetrating skyrmion
sublattice crystals, in agreement with low-$T$ spin textures found in earlier
works. We show by Monte Carlo simulations that this skyrmion crystal is stable
at finite temperatures below a critical temperature.",2204.12248v2
2022-09-06,Dynamic coupling and spin-wave dispersions in a magnetic hybrid system made of an artificial spin-ice structure and an extended NiFe underlayer,"We present a combined experimental and numerical study of the spin-wave
dispersion in NiFe artificial spin-ice (ASI) system consisting of an array of
stadium-shaped nanoislands deposited on the top of a continuous NiFe film with
nonmagnetic spacer layers of varying thickness. The spin-wave dispersion,
measured by wavevector resolved Brillouin light scattering spectroscopy in the
Damon-Eshbach configuration, consists of a rich number of modes, with either
stationary or propagating character. We find that the lowest frequency mode
displays a bandwidth of approximately 0.5 GHz, which is independent of the
presence of the film underneath. On the contrary, the BLS intensity of some of
the detected modes strongly depends on the presence of the extended thin-film
underlayer. Micromagnetic simulations unveil the details of the dynamic
coupling between ASI lattice and film underlayer. Interestingly, the ASI
lattice facilitates dynamics of the film either specific wavelengths or
intensity modulation peculiar to the modes of the ASI elements imprinted in the
film. Our results demonstrate that propagating spin waves can be modulated at
the nanometer length scale by harnessing the dynamic mode coupling in the
vertical, i.e., the out-of-plane direction of suitably designed magnonic
structures.",2209.02783v1
2022-11-30,Stark control of solid-state quantum memory with spin-wave storage,"Quantum memories for quantum communication need to be able to store photons
for an extended time and then to release them on demand. This can be achieved
in atomic frequency comb ensemble based quantum memories by control pulses that
transfer the excitation to and from long-lived spin states. However, such
pulses can give rise to coherent and incoherent noise due to their interaction
with the memory ensemble. In this article, we experimentally demonstrate the
ability to switch off the coherent noise from such control pulses during the
echo emission in a spin-wave quantum memory, using the linear Stark effect in
rare-earth-ion doped crystals. By applying an electric field pulse, the echo
emission was coherently switched off prior to the first spin transfer pulse,
and the stored data pulse was restored only when both an optical recall pulse
and a re-phasing electrical pulse were applied, giving a high degree of control
of both desired and undesired emissions. We estimate the effectiveness of this
technique by turning off the free induction decay of a narrow ensemble of ions.
This technique can thus improve the noise performance of spin-wave storage at
the single photon level by quenching coherent optical radiation created by the
strong control pulses. The method demonstrated here represents a
proof-of-principle that the spin-wave storage scheme can be combined with Stark
control. The combined scheme serves as an addition to the toolbox of techniques
that can be used to realize a full version of a quantum repeater.",2211.17206v1
2023-02-01,A Brillouin light scattering study of the spin-wave magnetic field dependence in a magnetic hybrid system made of an artificial spin-ice structure and a film underlayer,"We present a combined Brillouin light scattering and micromagnetic simulation
investigation of the magnetic-field dependent spin-wave spectra in a hybrid
structure made of permalloy (NiFe) artificial spin-ice (ASI) systems, composed
of stadium-shaped nanoislands, deposited on the top of an unpatterned permalloy
film with a nonmagnetic spacer layer. The thermal spin-wave spectra were
recorded by Brillouin light scattering (BLS) as a function of the magnetic
field applied along the symmetry direction of the ASI sample. Magneto-optic
Kerr effect magnetometry was used to measure the hysteresis loops in the same
orientation as the BLS measurements. The frequency and intensity of several
spin-wave modes detected by BLS were measured as a function of the applied
magnetic field. Micromagnetic simulations enabled us to identify the modes in
terms of their frequency and spatial symmetry and to extract information about
the existence and strength of the dynamic coupling, relevant only to a few
modes of a given hybrid system. Using this approach, we suggest a way to
understand if dynamic coupling between ASI and film modes is present or not,
with interesting implications for the development of future three-dimensional
magnonic applications and devices.",2302.00483v1
2023-11-12,A 50-spin surface acoustic wave Ising machine,"Time-multiplexed Spinwave Ising Machines (SWIMs) have unveiled a route
towards miniaturized, low-cost, and low-power solvers of combinatorial
optimization problems. While the number of supported spins is limited by the
nonlinearity of the spinwave dispersion, other collective excitations, such as
surface acoustic waves (SAWs), offer a linear dispersion. Here, we demonstrate
an all-to-all, fully FPGA reprogrammable, 50-spin surface acoustic wave-based
Ising machine (SAWIM), using a 50-mm-long Lithium Niobate SAW delay line,
off-the-shelf microwave components, and a low-cost FPGA. The SAWIM can solve
any 50-spin MAX-CUT problem, with arbitrary coupling matrices, in less than 340
$\mu$s consuming only 0.62 mJ, corresponding to close to 3000 solutions per
second and a figure of merit of 1610 solutions/W/s. We compare the SAWIM
computational results with those of a 100-spin optical Coherent Ising machine
and find a higher probability of solution. Moreover, we demonstrate that there
is an optimum overall coupling strength between spins at which the probability
of the exact solution reaches 100%. The SAWIM illustrates the general merits of
solid state wave-based time-multiplexed Ising machines in the microwave domain
as versatile platforms for commercially feasible high-performance solvers of
combinatorial optimization problems.",2311.06830v1
1997-06-24,"Is the ground state of alpha-(BEDT-TTF)2MHg(SCN)4[M=K,Rb,Tl] a charge-density wave or a spin-density wave?","The nature of the low-temperature phase of the quasi-two-dimensional
conductors $\alpha-(BEDT-TTF)_2{M}Hg(SCN)_4$[{M}=K,Rb,Tl] is considered. It is
argued that the magnetic field dependence of the phase diagram is more
consistent with a charge-density wave, rather than a spin-density wave ground
state. The phase diagram of a charge-density wave in a magnetic field is
discussed using a Ginzburg-Landau free energy derived from microscopic theory.
New experiments are proposed to test the charge-density-wave hypothesis and
detect an additional high field phase.",9706235v2
2003-11-20,Quantum Wave Resistance of Schrodinger functions,"The new concept of quantum wave-impedance (QWI), Z is introduced to answer
the question whether there is impedance to a Schrodinger wave. Z will be an
analogue of Maxwell's free space impedance (376.7 ohm) for electromagnetic
waves. We show, for free particle wave function, the value of Z is in general
not zero and purely real (resistive). As in quantum hall (QHE), Z can be
expressed in terms of the fine structure constant, the electromagnetic
permittivity and permeability of free space. Z is a determinant of the
partitioning and flow of charge and energy transported by the quantum system.
The scale factor of Z is about 12.9 kilo-ohms (per spin), so the corresponding
wave conductance G is (77.5 micro-mho, per spin) double the unit of Landaur
conductance. As functions of the quantum numbers (l,m,n) Z shows, peaks,
valleys and plateaus; also as in QHE, both integer and fractional steps may be
obtained. In microwave and optical technology, conventional impedance is an
essential parameter. The quantum impedance defined here will be no exception in
future technology.",0311479v1
2007-01-02,Quasi-One-Dimensional Spin-Density-Wave States with Two Kinds of Periodic Potentials and a Interchain Misfit,"Spin density wave (SDW) states of a quasi-one-dimensional system with an
incommensurate wave vector perpendicular to the chain have been studied in the
presence of two kinds of commensurate potentials, which originate in a
quarter-filled band and dimerization along the chain. In terms of a phase
variable of the SDW order parameter, we treat classically the two-dimensional
Hamiltonian, which includes both acoustic excitations with long wave length and
a vortex excitation with short wave length. A phase diagram on the plane of
temperature and chemical potential (where the latter corresponds to the
deviation of the transverse wave vector from the commensurate one) exhibits a
variety of states given by the commensurate SDW state without charge density,
the commensurate SDW state with charge density, the incommensurate SDW state
and the disordered state.",0701038v1
1997-02-21,Time dependent partial waves and vortex rings in the dynamics of wave packets,"We have found a new class of time dependent partial waves which are solutions
of time dependent Schr\""odinger equation for three dimensional harmonic
oscillator. We also showed the decomposition of coherent states of harmonic
oscillator into these partial waves. This decomposition appears perticularly
convenient for a description of the dynamics of a wave packet representing a
particle with spin when the spin--orbit interaction is present in the
hamiltonian. An example of an evolution of a localized wave packet into a torus
and backwards, for a particular initial conditions is analysed in analytical
terms and shown with a computer graphics.",9702043v1
2009-12-09,Formation of Random Dark Envelope Solitons from Incoherent Waves,"This letter reports experimental results on a new type of soliton: the random
temporal dark soliton. One excites an incoherent large-amplitude propagating
spin-wave packet in a ferromagnetic film strip with a repulsive, instantaneous
nonlinearity. One then observes the random formation of dark solitons from this
wave packet. The solitons appear randomly in time and in position relative to
the entire wave packet. They can be gray or black. For wide and/or very strong
spin-wave packets, one also observes multiple dark solitons. In spite of the
randomness of the initial wave packets and the random formation processes, the
solitons show signatures that are found for conventional coherent dark
solitons.",0912.1833v1
2015-07-01,Time-dependent many-variable variational Monte Carlo method for nonequilibrium strongly correlated electron systems,"We develop a time-dependent variational Monte Carlo (t-VMC) method for
quantum dynamics of strongly correlated electrons. The t-VMC method has been
recently applied to bosonic systems and quantum spin systems. Here, we propose
a time-dependent trial wave function with many variational parameters, which is
suitable for nonequilibrium strongly correlated electron systems. As the trial
state, we adopt the generalized pair-product wave function with correlation
factors and quantum-number projections. This trial wave function has been
proven to accurately describe ground states of strongly correlated electron
systems. To show the accuracy and efficiency of our trial wave function in
nonequilibrium states as well, we present our benchmark results for relaxation
dynamics during and after interaction quench protocols of fermionic Hubbard
models. We find that our trial wave function well reproduces the exact results
for the time evolution of physical quantities such as energy, momentum
distribution, spin structure factor, and superconducting correlations. These
results show that the t-VMC with our trial wave function offers an efficient
and accurate way to study challenging problems of nonequilibrium dynamics in
strongly correlated electron systems.",1507.00274v2
2017-08-09,Weak localization of magnons in chiral magnets,"We report on the impact of the Dzyaloshinskii-Moriya interaction on the
coherent backscattering of spin waves in a disordered magnetic material. This
interaction breaks the inversion symmetry of the spin-wave dispersion relation,
such that $\omega_\mathbf{k} = \omega_{2\mathbf{K}^\mathrm{I}-\mathbf{k}} \neq
\omega_{-\mathbf{k}}$, where $\mathbf{K}^\mathrm{I}$ is related to the
Dzyaloshinskii-Moriya vectors. As a result of numerical investigations we find
that the backscattering peak of a wave packet with initial wave vector
$\mathbf{k}_0$ shifts from $-\mathbf{k}_0$ to
$2\mathbf{K}^\mathrm{I}-\mathbf{k}_0$, such that the backscattering wave vector
and the initial wave vector are in general no longer antiparallel. The shifted
coherence condition is explained by a diagrammatic approach and opens up an
avenue to measure sign and magnitude of the Dzyaloshinskii-Moriya interaction
in weakly disordered chiral magnets.",1708.02807v1
2018-11-21,"Memory, Penrose Limits and the Geometry of Gravitational Shockwaves and Gyratons","The geometric description of gravitational memory for strong gravitational
waves is developed, with particular focus on shockwaves and their spinning
analogues, gyratons. Memory, which may be of position or velocity-encoded type,
characterises the residual separation of neighbouring `detector' geodesics
following the passage of a gravitational wave burst, and retains information on
the nature of the wave source. Here, it is shown how memory is encoded in the
Penrose limit of the original gravitational wave spacetime and a new `timelike
Penrose limit' is introduced to complement the original plane wave limit
appropriate to null congruences. A detailed analysis of memory is presented for
timelike and null geodesic congruences in impulsive and extended gravitational
shockwaves of Aichelburg-Sexl type, and for gyratons. Potential applications to
gravitational wave astronomy and to quantum gravity, especially infra-red
structure and ultra-high energy scattering, are briefly mentioned.",1811.08827v2
2020-09-14,Global propagation of massive quantum fields in the plane gravitational waves and electromagnetic backgrounds,"The behavior of massive quantum fields in the general plane wave spacetime
and external, non-plane, electromagnetic waves is studied. The asymptotic
conditions, the ""in"" (""out"") states and the cross sections are analysed. It is
observed that, despite of the singularities encountered, the global form of
these states can be obtained: at the singular points the Dirac delta-like
behavior emerges and there is a discrete change of phase of the wave function
after passing through each singular point. The relations between these phase
corrections and local charts are discussed. Some examples of waves of infinite
range (including the circularly polarized ones) are presented for which the
explicit form of solutions can be obtained. All these results concern both the
scalar as well as spin one-half fields; in the latter case the change of the
spin polarization after the general sandwich wave has passed is studied.",2009.06518v3
2021-10-28,Newman-Penrose-Debye formalism for fields of various spins in pp-wave backgrounds,"Using Newman-Penrose formalism in tetrad and spinor notation, we perform
separation of variables in the wave equations for massless fields of various
spins s=1/2, 1, 3/2, 2 on the background of exact plane-fronted gravitational
wave metrics. Then, applying Wald's method of adjoint operators, we derive
equations for Debye potentials generating these fields and find inverse
projection operators expressing multicomponet fields in terms of scalar
potentials. For a number of shock wave backgrounds, as a special case of
non-vacuum pp-waves, the exact solutions for Debye potentials are constructed
explicitly. The possibility of generalization to the case of massive fields, in
particular, construction of exact solutions to the Dirac and Proca equations
are discussed. These results can be used in supergravity models on pp-wave
backgrounds.",2110.15046v1
2020-01-20,Alphonons as the quanta of the Alfvén waves,"In a magnetized plasma, both the transverse and longitudinal Alfv\'en waves
carry an average energy density that, for each mode of oscillation, resembles
the classical energy of a harmonic oscillator with unit mass and angular
frequency that depends on the background magnetic field and plasma density. We
employ this fact to introduce a pair of canonical variables for the underlying
classical system, and then use the canonical quantization procedure to express
the Alfv\'en wave velocity (or the corresponding plasma displacement vector) in
terms of creation and annihilation operators. We thus introduce the concept of
Alphonons as the quanta for the Alfv\'en wave packets and study their
characteristic features. The corresponding quanta (Alphonons) carry spin one
for the transverse Alfv\'en wave and spin zero for the longitudinal Alfv\'en
wave. We obtained behavior of thermodynamic quantities for an Alphonon system
(e.g., free energy, entropy, specific heat). We showed that for the Alphonon
system the spectral energy density obeys the Planck's black body radiation law.",2001.08112v1
2020-05-29,Bound states of spin-orbit coupled cold atoms in a Dirac delta-function potential,"Dirac delta-function potential is widely studied in quantum mechanics because
it usually can be exactly solved and at the same time is useful in modeling
various physical systems. Here we study a system of delta-potential trapped
spinorbit coupled cold atoms. The spin-orbit coupled atomic matter wave has two
kinds of evanescent modes, one of which has pure imaginary wavevector and is an
ordinary evanescent wave; while the other with a complex number wave vector is
recognized as oscillating evanescent wave. We identified the eigenenergy
spectra and the existence of bound states in this system. The bound states can
be constructed analytically using the two kinds of evanescent modes and we
found that they exhibit typical features of stripe phase, separated phase or
zero-momentum phase. In addition to that, the properties of semi-bound states
are also discussed, which is a localized wave packet on a plane wave
background.",2005.14604v1
2020-07-27,Knotted Polarizations and Spin in 3D Polychromatic Waves,"We consider complex 3D polarizations in the interference of several vector
wave fields with different commensurable frequencies and polarizations. We show
that the resulting polarizations can form knots, and interfering three waves is
sufficient to generate a variety of Lissajous, torus, and other knot types. We
describe the spin angular momentum, generalized Stokes parameters and degree of
polarization for such knotted polarizations, which can be regarded as
partially-polarized. Our results are generic for any vector wave fields,
including, e.g., optical and acoustic waves. As a directly-observable example,
we consider knotted trajectories of water particles in the interference of
surface water (gravity) waves with three different frequencies.",2007.13307v2
2022-03-17,Traveling Wave Form Description for Dirac Field and Its Deduction To Pauli Equation Type Forms in Quantum Mechanics,"We derive an equivalent traveling wave form description for Dirac field. In
the non-relativistic limit, such form can reduce to inverse-Galilean
transformed Schrodinger-type equation. We find that, the resulting
two-component Schrodinger-type equation from the reduction of traveling wave
form description of Dirac field is different to the naive Galilean transformed
Schrodinger equation. Taking into account the interactions of the system to
electromagnetic field by adding proper forms of covariant derivative, the
traveling wave form description for Pauli equation can be similarly obtained in
the non-relativistic limit. Such descriptions allow one to choose arbitrary
convenient reference frame for quantum system involving spins. Using
Bargmann-Wigner formalism for field with arbitrary spin $s\geq 1/2$, which
satisfy Dirac-type equations in all its indices, the traveling wave description
for such a field can be similarly obtained from the traveling wave form
description of Dirac field, for example, for the spin-3/2 Rarita-Schwinger
field and spin-2 gravitational field.",2203.09005v1
2000-11-14,Resonances in one and two rows of triangular Josephson junction cells,"We present an experimental and analytical study of resonances in the
current-voltage characteristics of single and double row triangular Josephson
arrays. The magnetic field dependences of the voltage positions of the
resonances have been measured for various cell inductances and junction
critical currents. In double row arrays, we have observed a peculiar resonance,
whose voltage position decreases with magnetic field. We derive the spectrum of
linear electromagnetic waves propagating in the arrays. In the double row
array, the spectrum consists of many branches that differ by the behavior of
the Josephson junctions transverse to the bias current direction. The measured
magnetic field dependence of the resonance voltages is mapped to the linear
mode spectrum and good agreement between experiments and model is found.",0011237v1
2002-01-03,Cyclotron resonance in the layered perovskite superconductor Sr2RuO4,"We report a detailed study of the magnetic-field-orientation dependence of
the millimetre-wave magnetoconductivity of the superconductor Sr2RuO4 We find
two harmonic series of cyclotron resonances. We assign the first, corresponding
to a quasiparticle mass of $4.29 \pm 0.05 m_{\rm e}$, where $m_{\rm e}$ is the
free-electron mass, to the $\beta$ Fermi-surface section. We assign the second
series, which contains only odd harmonics, to cyclotron resonance of the
$\gamma$ Fermi-surface section, yielding a quasiparticle mass of $12.35 \pm
0.20 m_{\rm e}$. A third, single cyclotron resonance, corresponding to a
quasiparticle mass of $5.60 \pm 0.03 m_{\rm e}$, is attributed to the $\alpha$
Fermi-surface section. In addition, we find a very strong absorption mode in
the presence of a magnetic field component parallel to the
quasi-two-dimensional planes of the sample. Its dependence on the orientation
of the magnetic field cannot be described in the context of conventional
cyclotron resonance, and the origin of this mode is not yet clear.",0201032v1
2004-09-22,Interaction of magnetic-dipolar modes with microwave-cavity electromagnetic fields,"We discuss the problem of magnetic-dipolar oscillations combined with
microwave resonators. The energy density of magnetic-dipolar or magnetostatic
(MS) oscillations in ferrite resonators is not the electromagnetic-wave density
of the energy and not the exchange energy density as well. This fact reveals
very special behaviors of the geometrical effects. Compared to other
geometries, thin-film ferrite disk resonators exhibit very unique interactions
of MS oscillations with the cavity electromagnetic fields. MS modes in a flat
ferrite disk are characterized by a complete discrete spectrum of energy
levels. The staircase demagnetization energy in thin-film ferrite disks may
appear as noticeable resonant absorption of electromagnetic radiation. Our
experiments show how the environment may cause decoherence for magnetic
oscillations. Another noticeable fact is experimental evidence for
eigen-electric-moment oscillations in a ferrite disk resonator.",0409583v2
2004-11-23,Impact of the inherent periodic structure on the effective medium description of left-handed and related meta-materials,"We study the frequency dependence of the effective electromagnetic parameters
of left-handed and related meta-materials of the split ring resonator and wire
type. We show that the reduced translational symmetry (periodic structure)
inherent to these meta-materials influences their effective electromagnetic
response. To anticipate this periodicity, we formulate a periodic effective
medium model which enables us to distinguish the resonant behavior of
electromagnetic parameters from effects of the periodicity of the structure. We
use this model for the analysis of numerical data for the transmission and
reflection of periodic arrays of split ring resonators, thin metallic wires,
cut wires as well as the left-handed structures. The present method enables us
to identify the origin of the previously observed resonance/anti-resonance
coupling as well as the occurrence of negative imaginary parts in the effective
permittivities and permeabilities of those materials. Our analysis shows that
the periodicity of the structure can be neglected only for the wavelength of
the electromagnetic wave larger than 30 space periods of the investigated
structure.",0411590v1
2007-03-27,Resonance Microwave Absorption in He II.,"Microwave (MW) absorption in liquid 4He is investigated in the frequency
range of 40-200 GHz at T = 1.4 - 2.5 K. Whispering gallery of waves was
generated by a dielectric disc resonator immersed into the liquid. Resonance
absorption of MWs was detected at 180.3 GHz, which corresponds to the roton
minimum of the liquid helium excitation spectrum. The creation of a single
roton is possible because of the presence of the resonator wall which absorbs
an extra momentum. The resonance frequency is shown to decreases with
temperature in an excellent agreement with the temperature dependence of the
roton gap obtained previously in the neutron scattering experiment. The
temperature dependence of the MW absorption data indicates the anomalous
behavior near the lambda-point and displays the hysteretic character.",0703710v1
1999-07-16,Detection strategies for scalar gravitational waves with interferometers and resonant spheres,"We compute the response and the angular pattern function of an interferometer
for a scalar component of gravitational radiation in Brans-Dicke theory. We
examine the problem of detecting a stochastic background of scalar GWs and
compute the scalar overlap reduction function in the correlation between an
interferometer and the monopole mode of a resonant sphere. While the
correlation between two interferometers is maximized taking them as close as
possible, the interferometer-sphere correlation is maximized at a finite value
of f*d, where `f' is the resonance frequency of the sphere and `d' the distance
between the detectors. This defines an optimal resonance frequency of the
sphere as a function of the distance. For the correlation between the Virgo
interferometer located near Pisa and a sphere located in Frascati, near Rome,
we find an optimal resonance frequency f=590 Hz. We also briefly discuss the
difficulties in applying this analysis to the dilaton and moduli fields
predicted by string theory.",9907055v2
1999-11-30,Sustained resonance: a binary system perturbed by gravitational radiation,"The general phenomena associated with sustained resonance are studied in this
paper in connection with relativistic binary pulsars. We represent such a
system by two point masses in a Keplerian binary system that evolves via
gravitational radiation damping as well as an external tidal perturbation. For
further simplification, we assume that the external tidal perturbation is
caused by a normally incident circularly polarized monochromatic gravitational
wave. In this case, the second-order partially averaged equations are studied
and a theorem of C. Robinson is employed to prove that for certain values of
the physical parameters resonance capture followed by sustained resonance is
possible in the averaged system. We conjecture that sustained resonance can
occur in the physical system when the perturbing influences nearly balance each
other.",9911123v1
2003-07-09,Time delayed K+ N reactions and exotic baryon resonances,"Evidences and hints, both from the theoretical and experimental side, of
exotic baryon resonances with B=S, have been with us for the last thirty years.
The poor status of the general acceptance of these Z* resonances is partly due
to the prejudice against penta-quark baryons and partly due to the opinion that
a proof of the existence of exotic states must be rigorous. This can refer to
the quality and amount of data gathered, and also to the analytical methods
applied in the study of these resonances. It seems then mandatory that all
possibilities and aspects be exploited. We do that by analyzing the time delay
in K+ N scattering, encountering clear signals of the exotic Z* resonances
close to the pole values found in partial wave analyses.",0307134v2
2003-06-11,Pairing correlations and resonant states in the relativistic mean field theory,"We present a simple scheme for taking into account the resonant continuum
coupling in the Relativistic Mean Field- BCS (RMF-BCS) calculations. In this
scheme, applied before in non-relativistic calculations, the effect of the
resonant continuum on pairing correlations is introduced through the scattering
wave functions located in the region of the resonant states. These states are
found by solving the relativistic mean field equations with scattering-type
boundary conditions for continuum spectrum. The calculations are done for the
neutron-rich Zr isotopes. It is shown that the sudden increase of the neutron
radii close to the neutron drip line, the so-called giant halo, is determined
by a few resonant states close to the continuum threshold.",0306035v1
2005-11-23,Dynamical generation of $J^P=3/2-$ resonances and the $Λ(1520)$ resonance,"The lowest order chiral Lagrangian is used to study s-wave interactions of
the baryon decuplet with the octet of pseudoscalar mesons. The coupled channel
Bethe Salpeter equation is used to obtain dynamically generated
$\tfrac{3}{2}^-$ resonances in the partial wave amplitudes which provide a
reasonable description to a number of 3 and 4-star resonances like
$\Delta(1700)$, $\Lambda(1520)$, $\Sigma(1670)$, $\Sigma(1940)$, $\Xi(1820)$,
$\Omega(2250)$ etc. The phenomenological introduction of d-wave channels in the
coupled channel scheme along with the existing s-wave channels is shown to
provide a much improved description of the $\Lambda(1520)$ resonance. The
prediction of the absolute strength of the cross section in the reactions
$K^-p\to\Lambda\pi^0\pi^0$ and $K^-p\to\Lambda\pi^+\pi^-$ provided by this
scheme shows a good agreement with existing data.",0511062v1
1998-10-01,Resonance broadening theory of Farley-Buneman turbulence in the auroral E-region,"The conventional theory of resonance broadening for a two-species plasma in a
magnetic field is revised, and applied to an ionospheric turbulence case. The
assumptions made in the conventional theory of resonance broadening have, in
the past, led to replacing the frequency $\omega$ by
$\omega+ik_{\perp}^{2}D^{*}$ in the resonant part of the linear dielectric
function to obtain the nonlinear dielectric function. Where $D^{*}$ is an
anomalous diffusion coefficient due solely to wave scattering of the particle
orbits. We show that in general these assumptions are not valid, and
consequently the straightforward substitution of frequencies is not legitimate.
We remedy these problems and derive expressions for the time-dependent
components of the diffusion tensor. The improved resonance broadening theory is
developed in the context of an ionospheric problem, namely that of the
Farley-Buneman turbulence in the auroral E-region. A kinetic description of the
electrons is used. A general expression for the nonlinear dielectric function
is derived in the special case where no parallel electric field is present, and
the differences with the conventional dispersion relation are discussed.",9810061v1
2003-09-05,Opto-mechanical probes of resonances in amplifying microresonators,"We investigate whether the force and torque exerted by light pressure on an
irregularly shaped dielectric resonator allow to detect resonant frequencies,
delivering information complemental to the scattering cross section by
mechanical means. The peak-to-valley ratio in the torque signal can be many
times larger than in the scattering cross section, and, furthermore, depends on
the structure of the resonance wave pattern. The far-field emission pattern of
the associated quasi-bound states can be tested by the angular dependence of
the mechanical probes at finite amplification rate. We relate the force and
torque to the scattering matrix and present numerical results for an annularly
shaped dielectric resonator.",0309035v2
2004-02-29,Interferometric differentiation between resonant Coherent Anti-Stokes Raman Scattering and nonresonant four-wave-mixing processes,"A major impediment of using Coherent Anti-Stokes Raman Scattering to identify
biological molecules is that the illumination levels required to produce a
measurable signal often also produce significant nonresonant background from
the medium, especially from water, that is not specific to the resonance being
investigated. We present a method of using nonlinear interferometry to measure
the temporal shape of the anti-Stokes signal to differentiate which components
are resonant and nonresonant. This method is easily adaptable to most existing
pulsed CARS illumination methods and should allow for distinguishing resonant
CARS when using higher energy pulses. By examining the differences between
signals produced by acetone and water, we show that the resonant and
nonresonant signals can be clearly differentiated.",0403007v1
2002-03-25,Field quantization for open optical cavities,"We study the quantum properties of the electromagnetic field in optical
cavities coupled to an arbitrary number of escape channels. We consider both
inhomogeneous dielectric resonators with a scalar dielectric constant
$\epsilon({\bf r})$ and cavities defined by mirrors of arbitrary shape. Using
the Feshbach projector technique we quantize the field in terms of a set of
resonator and bath modes. We rigorously show that the field Hamiltonian reduces
to the system--and--bath Hamiltonian of quantum optics. The field dynamics is
investigated using the input--output theory of Gardiner and Collet. In the case
of strong coupling to the external radiation field we find spectrally
overlapping resonator modes. The mode dynamics is coupled due to the damping
and noise inflicted by the external field. For wave chaotic resonators the mode
dynamics is determined by a non--Hermitean random matrix. Upon including an
amplifying medium, our dynamics of open-resonator modes may serve as a starting
point for a quantum theory of random lasing.",0203122v2
2003-12-09,Quantum averaging and resonances: two-level atom in a one-mode quantized field,"We construct a non-perturbative approach based on quantum averaging combined
with resonant transformations to detect the resonances of a given Hamiltonian
and to treat them. This approach, that generalizes the rotating-wave
approximation, takes into account the resonances at low field and also at high
field (non-linear resonances). This allows to derive effective Hamiltonians
that contain the qualitative features of the spectrum, i.e. crossings and
avoided crossings, as a function of the coupling constant. At a second stage
the precision of the spectrum can be improved quantitatively by standard
perturbative methods like contact transformations. We illustrate this method to
determine the spectrum of a two-level atom interacting with a single mode of a
quantized field.",0312077v1
2007-02-05,Two-level systems driven by large-amplitude fields,"We analyze the dynamics of a two-level system subject to driving by
large-amplitude external fields, focusing on the resonance properties in the
case of driving around the region of avoided level crossing. In particular, we
consider three main questions that characterize resonance dynamics: (1) the
resonance condition, (2) the frequency of the resulting oscillations on
resonance and (3) the width of the resonance. We identify the regions of
validity of different approximations. In a large region of the parameter space,
we use a geometric picture in order to obtain both a simple understanding of
the dynamics and quantitative results. The geometric approach is obtained by
dividing the evolution into discrete time steps, with each time step described
by either a phase shift on the basis states or a coherent mixing process
corresponding to a Landau-Zener crossing. We compare the results of the
geometric picture with those of a rotating-wave approximation. We also comment
briefly on the prospects of employing strong driving as a useful tool to
manipulate two-level systems.",0702032v3
2008-02-12,Low-lying dipole resonance in neutron-rich Ne isotopes,"Microscopic structure of the low-lying isovector dipole excitation mode in
neutron-rich $^{26,28,30}$Ne is investigated by performing deformed
quasiparticle-random-phase-approximation (QRPA) calculations. The particle-hole
residual interaction is derived from a Skyrme force through a Landau-Migdal
approximation. We have obtained the low-lying resonance in $^{26}$Ne at around
8.5 MeV. It is found that the isovector dipole strength at $E_{x}<10$ MeV
exhausts about 6.0% of the classical Thomas-Reiche-Kuhn dipole sum rule. This
excitation mode is composed of several QRPA eigenmodes, one is generated by a
$\nu(2s^{-1}_{1/2} 2p_{3/2})$ transition dominantly, and the other mostly by a
$\nu(2s^{-1}_{1/2} 2p_{1/2})$ transition. The neutron excitations take place
outside of the nuclear surface reflecting the spatially extended structure of
the $2s_{1/2}$ wave function. In $^{30}$Ne, the deformation splitting of the
giant resonance is large, and the low-lying resonance is overlapping with the
giant resonance.",0802.1687v1
2008-02-26,Study of $η$ photoproduction on the proton in a chiral constituent quark approach via one-gluon-exchange model,"A formalism based on a chiral quark model ($\chi$QM) approach complemented
with a one-gluon exchange model, to take into account the breakdown of the
$SU(6)\otimes O(3)$ symmetry, is presented. The configuration mixing of wave
functions for nucleon and resonances are derived. % With few adjustable
parameters, differential cross-section and polarized beam asymmetry for the
$\gamma p \to \eta p$ process are calculated and successfully compared with the
data in the centre-of-mass energy range from threshold up to 2 GeV. The known
resonances $S_{11}(1535)$, $S_{11}(1650)$, $P_{13}(1720)$, $D_{13}(1520)$, and
$F_{15}(1680)$, as well as two new $S_{11}$ and $D_{15}$ resonances are found
to be dominant in the reaction mechanism. Besides, connections among the
scattering amplitudes of the $\chi$QM approach and the helicity amplitudes, as
well as decay widths of resonances are established. Possible contributions from
the so-called ""missing resonances"" are investigated and found to be negligible.",0802.3816v1
2008-05-07,On-Chip Hotplate for Temperature Control of Cmos Saw Resonators,"Due to the sensitivity of the piezoelectric layer in surface acoustic wave
(SAW) resonators to temperature, a method of achieving device stability as a
function of temperature is required. This work presents the design, modeling
and characterization of integrated dual-serpentine polysilicon resistors as a
method for temperature control of CMOS SAW resonators. The design employs the
oven control temperature stabilization scheme where the device's temperature is
elevated to higher than Tmax to maintain constant device temperature. The
efficiency of the polysilicon resistor as a heating element was verified
through a 1-D partial differential equation model, 3-D CoventorWare finite
element simulations and measurements using Compix thermal camera. To verify
that the on-chip hotplate is effective as a temperature control method, both DC
and RF measurements of the heater together with the resonator were conducted.
Experimental results have indicated that the TCF of the CMOS SAW resonator of
-97.2 ppm/deg C has been reduced to -23.19 ppm/deg C when heated to 56 deg C.",0805.0930v1
2008-12-15,Negative Group Velocity from Quadrupole Resonance of Plasmonic Spheres,"We study the dispersions of plasmonic bands that arise from the coupling of
electric quadrupole resonances in three dimensional photonic crystals (PCs)
consisting of plasmonic spheres. Through analytical derivation, we show that
two branches of quadrupole bands in simple cubic PCs with a small lattice
constant possess negative group velocities. Distinct from double negative media
in which the negative responses originates from the coupling of electric and
magnetic responses (P and M), the negative dispersion induced by quadrupole
resonance is an intrinsic property of quadrupole that does not require coupling
to another degree of freedom. In addition, there is no simple effective medium
description. In plasmonic systems composed of metallic nanoparticle clusters,
the coupled quadrupole resonance may be tuned to lower optical frequencies, and
the coupling strength between this quadrupole resonance and external
electromagnetic (EM) waves are in the same order of the magnetic dipole M.",0812.2717v1
2009-12-14,Regge-plus-resonance predictions for charged-kaon photoproduction from the deuteron,"We present a Regge-inspired effective-Lagrangian framework for charged-kaon
photoproduction from the deuteron. Quasi-free kaon production is investigated
using the Regge-plus-resonance elementary operator within the non-relativistic
plane-wave impulse approximation. The Regge-plus-resonance model was developed
to describe photoinduced and electroinduced kaon production off protons and can
be extended to strangeness production off neutrons. The non-resonant
contributions to the amplitude are modelled in terms of K+(494) and K*+(892)
Regge-trajectory exchange in the t-channel. This amplitude is supplemented with
a selection of s-channel resonance-exchange diagrams. We investigate several
sources of theoretical uncertainties on the semi-inclusive charged-kaon
production cross section. The experimental error bars on the photocoupling
helicity amplitudes turn out to put severe limits on the predictive power when
considering quasi-free kaon production on a bound neutron.",0912.2679v1
2010-01-04,Above threshold s-wave resonances illustrated by the 1/2$^+$ states in $^9$Be and $^9$B,"We solve the persistent problem of the structure of the lowest $1/2^+$
resonance in $^9$Be which is important to bridge the A=8 gap in nucleosynthesis
in stars. We show that the state is a genuine three-body resonance even though
it decays entirely into neutron-$^8$Be relative s-waves. The necessary barrier
is created by ""dynamical"" evolution of the wave function as the short-distance
$\alpha$-$^5$He structure is changed into the large-distance n-$^8$Be
structure. This decay mechanism leads to a width about two times smaller than
table values. The previous interpretations as a virtual state or a two-body
resonance are incorrect. The isobaric analog 1/2$^+$ state in $^9$B is found to
have energy and width in the vicinity of 2.0 MeV and 1.5 MeV, respectively. We
also predict another 1/2$^+$ resonance in $^9$B with similar energy and width.",1001.0459v1
2010-04-05,Sub-Fourier characteristics of a $δ$-kicked rotor resonance,"We experimentally investigate the sub-Fourier behavior of a $\delta$-kicked
rotor resonance by performing a measurement of the fidelity or overlap of a
Bose-Einstein condensate (BEC) exposed to a periodically pulsed standing wave.
The temporal width of the fidelity resonance peak centered at the Talbot time
and zero initial momentum exhibits an inverse cube pulse number ($1/N^{3}$)
dependent scaling compared to a $1/N^{2}$ dependence for the mean energy width
at the same resonance. A theoretical analysis shows that for an accelerating
potential the width of the resonance in acceleration space depends on
$1/N^{3}$, a property which we also verify experimentally. Such a sub-Fourier
effect could be useful for high precision gravity measurements.",1004.0683v2
2010-05-17,Experimental demonstration of higher-order Laguerre-Gauss mode interferometry,"The compatibility of higher-order Laguerre-Gauss (LG) modes with
interferometric technologies commonly used in gravitational wave detectors is
investigated. In this paper we present the first experimental results
concerning the performance of the LG33 mode in optical resonators. We show that
the Pound-Drever-Hall error signal for a LG33 mode in a linear optical
resonator is identical to that of the more commonly used LG00 mode, and
demonstrate the feedback control of the resonator with a LG33 mode. We
succeeded to increase the mode purity of a LG33 mode generated using a
spatial-light modulator from 51% to 99% upon transmission through a linear
optical resonator. We further report the experimental verification that a
triangular optical resonator does not transmit helical LG modes.",1005.2990v3
2010-06-09,Observation of superluminal geometrical resonances in Bi2Sr2CaCu2O8+x intrinsic Josephson junctions,"We study Fiske steps in small Bi2Sr2CaCu2O8+x mesa structures, containing
only few stacked intrinsic Josephson junctions. Careful alignment of magnetic
field prevents penetration of Abrikosov vortices and facilitates observation of
a large variety of high quality geometrical resonances, including superluminal
with velocities larger than the slowest velocity of electromagnetic waves. A
small number of junctions limits the number of resonant modes and allows
accurate identification of modes and velocities. It is shown that superluminal
geometrical resonances can be excited by subluminal fluxon motion and that
flux-flow itself becomes superluminal at high magnetic fields. We argue that
observation of high-quality superluminal geometrical resonances is crucial for
realization of the coherent flux-flow oscillator in the THz frequency range.",1006.1751v1
2010-12-20,Phonon Resonators : The Building Blocks of Nanocomposite Adjusting the Electron - Phonon Interaction,"The nanocrystallite have the finite number of the oscillation modes. Their
number increases proportionally to a cube of the characteristic size. Thus the
oscillation spectrum of nanocrystal becomes discrete, and the separate modes of
oscillations does not interact with each other, that considerably strengthens
all phonon modulated processes in a crystal. Covering of such a nanocrystallite
with the shielding surface of a material with the higher nuclear weight will
allow to create the phonon resonators whose oscillation modes will represent
the standing waves and, will be amplified by the resonant manner. The
composites made of phonon resonators will allow to produce a perspective
functional material for the electronics with adjustable structure and
properties. Some new mechanism of HTS based on phonon resonators is proposed.",1012.4286v1
2011-10-06,Competition of resonant and nonresonant paths in resonance-enhanced two-photon single ionization of He by an ultrashort extreme-ultraviolet pulse,"We theoretically study the pulse-width dependence of the photoelectron
angular distribution (PAD) from the resonance-enhanced two-photon single
ionization of He by femtosecond ($\lesssim 20$ fs) extreme-ultraviolet pulses,
based on the time-dependent perturbation theory and simulations with the full
time-dependent Schr\""odinger equation. In particular, we focus on the
competition between resonant and nonresonant ionization paths, which leads to
the relative phase $\delta$ between the $S$ and $D$ wave packets distinct from
the corresponding scattering phase shift difference. When the spectrally
broadened pulse is resonant with an excited level, the competition varies with
pulse width, and, therefore, $\delta$ and the PAD also change with it. On the
other hand, when the Rydberg manifold is excited, $\delta$ and the PAD do not
much vary with the pulse width, except for the very short pulse regime.",1110.1139v3
2012-02-25,Near-Field Resonance at Far-Field Anti-Resonance: Plasmonically Enhanced Light Emission with Minimum Scattering Nanoantennas,"We demonstrate that a periodic array of optical antennas sustains a resonant
Near-Field (NF) and an anti-resonant Far-Field (FF) at the same energy and
in-plane momentum. This phenomenon arises in the context of coupled plasmonic
lattice resonances, whose bright and dark character is interchanged at a
critical antenna length. The energies of these modes anti-cross in the FF, but
cross in the NF. Hence, we observe an extremely narrow bandwidth emission
enhancement from quantum dots in the proximity of the array, while the antennas
scatter minimally into the FF. Simulations reveal that a standing wave with a
quadrupolar field distribution is the origin of this dark collective resonance.",1202.5681v1
2013-03-25,High quality factor mg-scale silicon mechanical resonators for 3-mode optoacoustic parametric amplifiers,"Milligram-scale resonators have been shown to be suitable for the creation of
3-mode optoacoustic parametric amplifiers, based on a phenomena first predicted
for advanced gravitational-wave detectors. To achieve practical optoacoustic
parametric amplification, high quality factor resonators are required. We
present millimetre-scale silicon resonators designed to exhibit a torsional
vibration mode with a frequency in the 10^5 - 10^6 Hz range, for observation of
3-mode optoacoustic interactions in a compact table-top system. Our design
incorporates an isolation stage and minimizes the acoustic loss from optical
coating. We observe a quality factor of 7.5 x 10^5 for a mode frequency of
401.5 kHz, at room temperature and pressure of 10^-3 Pa. We confirmed the mode
shape by mapping the amplitude response across the resonator and comparing to
finite element modelling. This study contributes towards the development of
3-mode optoacoustic parametric amplifiers for use in novel high-sensitivity
signal transducers and quantum measurement experiments.",1303.6595v1
2013-08-29,Coherently opening a high-Q cavity,"We propose a general framework to effectively `open' a high-Q resonator, that
is, to release the quantum state initially prepared in it in the form of a
traveling electromagnetic wave. This is achieved by employing a mediating mode
that scatters coherently the radiation from the resonator into a
one-dimensional continuum of modes such as a waveguide. The same mechanism may
be used to `feed' a desired quantum field to an initially empty cavity.
Switching between an `open' and `closed' resonator may then be obtained by
controlling either the detuning of the scatterer or the amount of time it
spends in the resonator. First, we introduce the model in its general form,
identifying (i) the traveling mode that optimally retains the full quantum
information of the resonator field and (ii) a suitable figure of merit that we
study analytically in terms of the system parameters. Then, we discuss two
feasible implementations based on ensembles of two-level atoms interacting with
cavity fields. In addition, we discuss how to integrate traditional cavity QED
in our proposal using three-level atoms.",1308.6467v2
2013-12-10,Slow sound propagation in lossy locally resonant periodic structures,"We investigate the sound propagation in an air-filled tube periodically
loaded with Helmholtz resonators. By tuning the Helmholtz with the Bragg
resonance, we study the efficiency of slow sound propagation in the presence of
the intrinsic viscothermal losses of the system. While in the lossless case the
overlapping of the resonances results in slow sound induced transparency of a
narrow frequency band surrounded by a strong and broadband gap, the inclusion
of the unavoidable losses imposes limits to the slowdown factor and the maximum
transmission. Experiments, theory and finite element simulations have been used
for the characterization of acoustic wave propagation. Experiments, in good
agreement with the lossy theory, reveal the possibility of slowing sound at low
frequencies by 20 times. A trade-off among the relevant parameters (delay time,
maximum transmission, bandwidth) as a function of the tuning between Bragg and
Helmholtz resonance frequency is also presented.",1312.2851v1
2014-02-11,"Spectroscopy of the D1-transition of cesium by dressed-state resonance fluorescence from a single (In,Ga)As/GaAs quantum dot","We use a laser-driven single (In,Ga)As quantum dot (QD) in the dressed state
regime of resonance fluorescence ($T = 4$ K) to observe the four
$D_1$-transition lines of alkali atomic cesium ($Cs$) vapor at room
temperature. We tune the frequency of the dressing continuous-wave laser in the
vicinity of the bare QD resonance $\sim 335.116$ THz ($\sim 894.592$ nm) at
constant excitation power and thereby controllably tune the center and side
channel frequencies of the probe light, i.e. the Mollow triplet. Resonances
between individual QD Mollow triplet lines and the atomic hyperfine-split
transitions are clearly identified in the $Cs$ absorption spectrum. Our results
show that narrow-band (In,Ga)As QD resonance fluorescence (RF) is suitable to
optically address individual transitions of the $D_1$ quadruplet without
applying magnetic field or electric field tuning.",1402.2396v1
2014-04-07,$^4{\rm He}$+$n$+$n$ continuum within an ab initio framework,"The low-lying continuum spectrum of the $^6{\rm He}$ nucleus is investigated
for the first time within an ab initio framework that encompasses the $^4{\rm
He}$+$n$+$n$ three-cluster dynamics characterizing its lowest decay channel.
This is achieved through an extension of the no-core-shell model combined with
the resonating-group method, in which energy-independent non-local interactions
among three nuclear fragments can be calculated microscopically starting from
realistic nucleon-nucleon interactions and consistent ab initio many-body wave
functions of the clusters. The three-cluster Schr\""odinger equation is solved
with three-body scattering boundary conditions by means of the
hyperspherical-harmonic method on a Lagrange mesh. Using a soft
similarity-renormalization-group evolved chiral nucleon-nucleon potential, we
find the known $J^\pi = 2^+$ resonance as well as a result consistent with a
new low-lying second $2^+$ resonance recently observed at GANIL at $2.6$ MeV
above the $^6$He ground state. We also find resonances in the $2^-$, $1^+$ and
$0^-$ channels, while no low-lying resonances are present in the $0^+$ and
$1^-$ channels.",1404.1960v1
2014-05-05,Resonant metallic states in driven quasiperiodic lattices,"We consider a quasiperiodic Aubry-Andre (AA) model and add a weak
time-periodic and spatially quasiperiodic perturbation. The undriven AA model
is chosen to be well in the insulating regime. The spatial quasiperiodic
perturbation extends the model into two dimensions in reciprocal space. For a
spatial resonance which reduces the reciprocal space dynamics to an effective
one-dimensional two-leg ladder case, the ac perturbation resonantly couples
certain groups of localized eigenstates of the undriven AA model and turns them
into extended metallic ones. Slight detuning of the spatial and temporal
frequencies off resonance returns these states into localized ones. We analyze
the details of the resonant metallic eigenstates using Floquet representations.
In particular, we find that their size grows linearly with the system size.
Initial wave packets overlap with resonant metallic eigenstates and lead to
ballistic spreading.",1405.0765v1
2014-05-06,Giant second harmonic generation by engineering of double plasmonic resonances at nanoscale,"We have investigated second harmonic generation (SHG) from Ag-coated LiNbO3
(LN) core-shell nanocuboids and found that giant SHG can occur via deliberately
designed double plasmonic resonances. By controlling the aspect ratio, we can
tune fundamental wave (FW) and SHG signal to match the longitudinal and
transverse plasmonic modes simultaneously, and achieve giant enhancement of SHG
by more than five orders of magnitude in comparison to a bare LN nanocuboid and
by about one order of magnitude to the case adopting only single plasmonic
resonance. The underlying key physics is that the double-resonance nanoparticle
enables greatly enhanced trapping and harvesting of incident FW energy,
efficient internal transfer of optical energy from FW to SHW, and much improved
power to transport the SHG energy from the nanoparticle to the far-field
region. The proposed double-resonance nanostructure can serve as an efficient
subwavelength coherent light source through SHG and enable flexible engineering
of light-matter interaction at nanoscale.",1405.1381v1
2014-07-28,Remarks on pole trajectories for resonances,"We discuss in general terms pole trajectories of resonances coupling to a
continuum channel as some strength parameter is varied. It is demonstrated
that, regardless the underlying dynamics, the trajectories of poles that couple
to the continuum in a partial wave higher than s-wave are qualitatively the
same, while in case of s-waves the pole trajectory can reveal important
information on the internal structure of the resonance. In addition we show
that only molecular (or extraordinary) states appear near thresholds naturally,
while more compact structures need a significant fine tuning in the parameters.
  This study is of current relevance especially in strong interaction physics,
since lattice QCD may be employed to deduce the pole trajectories for hadronic
resonances as a function of the quark mass thus providing additional, new
access to the structure of s-wave resonances.",1407.7452v1
2014-09-12,Enhancement of polarizabilities of cylinders with cylinder-slab resonances,"If an object is very small in size compared with the wavelength of light, it
does not scatter light efficiently. It is hence difficult to detect a very
small object with light. We show using analytic theory as well as full wave
numerical calculation that the effective polarizability of a small cylinder can
be greatly enhanced by coupling it with a superlens type metamaterial slab.
This kind of enhancement is not due to the individual resonance effect of the
metamaterial slab, nor due to that of the object, but is caused by a collective
resonant mode between the cylinder and the slab. We show that this type of
particle-slab resonance which makes a small two-dimensional object much
brighter is actually closely related to the reverse effect known in the
literature as cloaking by anomalous resonance which can make a small cylinder
undetectable. We also show that the enhancement of polarizability can lead to
strongly enhanced electromagnetic forces that can be attractive or repulsive,
depending on the material properties of the cylinder.",1409.3680v1
2014-10-20,Comparison of gold- and graphene-based resonant nano-structures for terahertz metamaterials and an ultra-thin graphene-based modulator,"Graphene exhibits unique material properties and in electromagnetic wave
technology, it raises the prospect of devices miniaturized down to the atomic
length scale. Here we study split-ring resonator metamaterials made from
graphene and we compare them to gold-based metamaterials. We find that
graphene's huge reactive response derived from its large kinetic inductance
allows for deeply subwavelength resonances, although its resonance strength is
reduced due to higher dissipative loss damping and smaller dipole coupling.
Nevertheless, tightly stacked graphene rings may provide for negative
permeability and the electric dipole resonance of graphene meta-atoms turns out
to be surprisingly strong. Based on these findings, we present a terahertz
modulator based on a metamaterial with a multi-layer stack of alternating
patterned graphene sheets separated by dielectric spacers. Neighbouring
graphene flakes are biased against each other, resulting in modulation depths
of over 75% at a transmission level of around 90%.",1410.5318v1
2014-11-24,"Resonances for the Laplacian on Riemannian symmetric spaces: the case of SL(3,$\mathbb{R}$)/SO(3)","We show that the resolvent of the Laplacian on SL(3,$\mathbb{R}$)/SO(3) can
be lifted to a meromorphic function on a Riemann surface which is a branched
covering of $\mathbb{C}$. The poles of this function are called the resonances
of the Laplacian. We determine all resonances and show that the corresponding
residue operators are given by convolution with spherical functions
parameterized by the resonances. The ranges of these operators are infinite
dimensional irreducible SL(3,$\mathbb{R}$)-representations. We determine their
Langlands parameters and wave front sets. Also, we show that precisely one of
these representations is unitarizable. Alternatively, they are given by the
differential equations which determine the image of the Poisson transform
associated with the resonance.",1411.6527v2
2015-01-10,Cascaded Brillouin lasing in monolithic barium fluoride whispering gallery mode resonators,"We report the observation of stimulated Brillouin scattering and lasing at
1550~nm in barium fluoride (BaF$_2$) crystal. Brillouin lasing was achieved
with ultra-high quality ($Q$) factor monolithic whispering gallery mode (WGM)
mm-size disk resonators. Overmoded resonators were specifically used to provide
cavity resonances for both the pump and all Brillouin Stokes waves. Single and
multiple Brillouin Stokes radiations with frequency shift ranging from $8.2$
GHz up to $49$ GHz have been generated through cascaded Brillouin lasing.
BaF$_2$ resonator-based Brillouin lasing can find potential applications for
high-coherence lasers and microwave photonics.",1501.02327v1
2015-02-15,Experimental Observation of Resonance-Assisted Tunneling,"We present the first experimental observation of resonance-assisted
tunneling, a wave phenomenon, where regular-to-chaotic tunneling is strongly
enhanced by the presence of a classical nonlinear resonance chain. For this we
use a microwave cavity made of oxygen free copper with the shape of a
desymmetrized cosine billiard designed with a large nonlinear resonance chain
in the regular region. It is opened in a region, where only chaotic dynamics
takes place, such that the tunneling rate of a regular mode to the chaotic
region increases the line width of the mode. Resonance-assisted tunneling is
demonstrated by (i) a parametric variation and (ii) the characteristic plateau
and peak structure towards the semiclassical limit.",1502.04263v2
2015-02-24,Selective excitations of a Kerr-nonlinear resonator: exactly solvable approach,"We study Kerr nonlinear resonators (KNR) driven by a continuous wave field in
quantum regimes where strong Kerr interactions give rise to selective resonant
excitations of oscillatory modes. We use an exact quantum theory of KNR in the
framework of the Fokker-Planck equation without any quantum state truncation or
perturbation procedure. This approach allows non-perturbative consideration of
KNR for various quantum operational regimes including cascaded processes
between oscillatory states. We focus on understanding of multi-photon
non-resonant and selective resonant excitations of introcavity mode depending
on the detuning, the amplitude of the driving field and the strength of
nonlinearity. The analysis is provided on the base of photon number
distributions, the photon-number correlation function and the Wigner function.",1502.06975v2
2015-03-04,Laser induced Zero-Group Velocity resonances in Transversely Isotropic cylinder,"The transient response of an elastic cylinder to a laser impact is studied.
When the laser source is a line perpendicular to the cylinder axis, modes
guided along the cylinder are generated. For a millimetric steel cylinder up to
ten narrow resonances can be locally detected by laser interferometry below 8
MHz. Most of these resonances correspond to Zero-Group Velocity guided modes
while a few others can be ascribed to thickness modes. We observe that the
theory describing the propagation of elastic waves in an isotropic cylinder is
not sufficient to precisely predict the resonance spectrum. In fact, the
texture of such elongated structure manifest as elastic anisotropy. Thus, a
transverse isotropic (TI) model is used to calculate the dispersion curves and
compare them with the measured one, obtained by moving the source along the
cylinder. The five elastic constants of a TI cylinder are adjusted leading to a
good agreement between measured and theoretical dispersion curves. Then, all
the resonance frequencies are satisfactorily identified.",1503.01459v1
2016-01-11,Establishing mass spectrum of $S=-1$ hyperon resonances via a dynamical coupled-channels analysis of $K^-p$ reactions,"We report our recent effort for the extraction of resonance parameters
(complex pole mass and residues etc.) associated with Lambda* and Sigma*
hyperons. This was accomplished via a comprehensive partial-wave analysis of
the data for K^- p --> barK N, pi Sigma, pi Lambda, eta Lambda, K Xi reactions
from the thresholds up to W=2.1 GeV within a dynamical coupled-channels
approach. The results suggest a possible existence of new narrow J^P=3/2^+
\Lambda resonance with pole mass 1671^{+2}_{-8} -i(5^{+11}_{-2}) MeV, located
close to the eta Lambda threshold. This resonance is found to be responsible
for reproducing the data for K^-p --> eta Lambda differential cross sections
near the threshold, and thus the data seem favor its existence. The extracted
poles for J^P=1/2^- Lambda resonances below the barK N threshold, including
Lambda(1405), are also presented.",1601.02322v1
2016-05-01,"III-V semiconductor nano-resonators-a new strategy for passive, active, and nonlinear all-dielectric metamaterials","Metamaterials comprising assemblies of dielectric resonators have attracted
much attention due to their low intrinsic loss and isotropic optical response.
In particular, metasurfaces made from silicon dielectric resonators have shown
desirable behaviors such as efficient nonlinear optical conversion, spectral
filtering and advanced wave-front engineering. To further explore the potential
of dielectric metamaterials, we present all-dielectric metamaterials fabricated
from epitaxially grown III-V semiconductors that can exploit the high
second-order optical susceptibilities of III-V semiconductors, as well as the
ease of monolithically integrating active/gain media. Specifically, we create
GaAs nano-resonators using a selective wet oxidation process that forms a low
refractive index AlGaO (n~1.6) under layer similar to silicon dielectric
resonators formed using silicon-on-insulator wafers. We further use the same
fabrication processes to demonstrate multilayer III-V dielectric resonator
arrays that provide us with new degrees of freedom in device engineering. For
these arrays, we experimentally measure ~100% reflectivity over a broad
spectral range. We envision that all-dielectric III-V semiconductor
metamaterials will open up new avenues for passive, active and nonlinear all
dielectric metamaterials",1605.00298v1
2016-08-18,Super-resonant radiation stimulated by high-harmonics,"Solitons propagating in media with higher order dispersion will shed
radiation known as dispersive wave or resonant radiation, with applications in
frequency broadening, deep UV sources for spectroscopy or simply fundamental
studies of soliton physics. Starting from a recently proposed equation that
models the behaviour of ultrashort optical pulses in nonlinear materials using
the analytic signal, we find that the resonant radiation associated with the
third-harmonic generation term of the equation is parametrically stimulated
with an unprecedented gain. Resonant radiation levels, typically only a small
fraction of the soliton, are now as intense as the soliton itself. The
mechanism is quite universal and works also in normal dispersion and with
harmonics higher than the third. We report experimental hints of this
super-resonant radiation stimulated by the fifth harmonic in diamond.",1608.05222v1
2016-09-01,Non-Markovian dynamics of a superconducting qubit in an open multimode resonator,"We study the dynamics of a transmon qubit that is capacitively coupled to an
open multimode superconducting resonator. Our effective equations are derived
by eliminating resonator degrees of freedom while encoding their effect in the
Green's function of the electromagnetic background. We account for the
dissipation of the resonator exactly by employing a spectral representation for
the Green's function in terms of a set of non-Hermitian modes and show that it
is possible to derive effective Heisenberg-Langevin equations without resorting
to the rotating wave, two level or Markov approximations. A well-behaved time
domain perturbation theory is derived to systematically account for the
nonlinearity of the transmon. We apply this method to the problem of
spontaneous emission, capturing accurately the non-Markovian features of the
qubit dynamics, valid for any qubit-resonator coupling strength.",1609.00359v3
2016-09-19,Polarization-tailored Fano interference in plasmonic crystals: A Mueller matrix model of anisotropic Fano resonance,"We present a simple yet elegant Mueller matrix approach for controlling the
Fano interference effect and engineering the resulting asymmetric spectral line
shape in anisotropic optical system. The approach is founded on a generalized
model of anisotropic Fano resonance, which relates the spectral asymmetry to
two physically meaningful and experimentally accessible parameters of
interference, namely, the Fano phase shift and the relative amplitudes of the
interfering modes. The differences in these parameters between orthogonal
linear polarizations in an anisotropic system are exploited to desirably tune
the Fano spectral asymmetry using pre- and post-selection of optimized
polarization states. Experimental control on the Fano phase and the relative
amplitude parameters and resulting tuning of spectral asymmetry is demonstrated
in waveguided plasmonic crystals using Mueller matrix-based polarization
analysis. The approach enabled tailoring of several exotic regimes of Fano
resonance including the complete reversal of the spectral asymmetry. The
demonstrated control and the ensuing large tunability of Fano resonance in
anisotropic systems shows potential for Fano resonance-based applications
involving control and manipulation of electromagnetic waves at the nano scale.",1609.05777v1
2016-10-11,Resonance poles and threshold energies for hadron physical problems by a model-independent universal algorithm,"We show how complex resonance poles and threshold energies for systems in
hadron physics can be accurately obtained by using a method based on the
Pad\'{e}-approximant which was recently developed for the calculation of
resonance poles for atomic and molecular auto-ionization systems. The main
advantage of this method is the ability to calculate the resonance poles and
threshold energies from \emph{real} spectral data. In order to demonstrate the
capabilities of this method we apply it here to an analytical model as well as
to experimental data for the squared modulus of the vector pion form factor,
the S0 partial wave amplitude for $\pi\pi$ scattering and the cross section
ratio $R(s)$ for $e^+e^-$ collisions. The extracted values for the resonance
poles of the $\rho(770)$ and the $f_0(500)$ or $\sigma$ meson are in very good
agreement with the literature. When the data are noisy the prediction of decay
thresholds proves to be less accurate but feasible.",1610.03252v2
2017-07-22,Subwavelength sound screening by coupling space-coiled Fabry-Perot resonators,"We explore broadband and omnidirectional low frequency sound screening based
on locally resonant acoustic metamaterials. We show that the coupling of
different resonant modes supported by Fabry-Perot cavities can efficiently
generate asymmetric lineshapes in the transmission spectrum, leading to a
broadband sound opacity. The Fabry-Perot cavities are space-coiled in order to
shift the resonant modes under the diffraction edge, which guaranty the opacity
band for all incident angles. Indeed, the deep subwavelength feature of the
cavities leads to avoid diffraction that have been proved to be the main
limitation of omnidirectional capabilities of locally resonant perforated
plates. We experimentally reach an attenuation of few tens of dB at low
frequency, with a metamaterial thickness fifteen times smaller than the
wavelength (lambda / 15). The proposed design can be considered as a new
building block for acoustic metasurfaces having a high level of manipulation of
acoustic waves.",1707.07208v1
2017-12-04,Femtosecond pulse with THz repetition frequency based on strong coupling between quantum emitters and a plasmonic resonator,"Nanoscale pulsed light is highly desirable in nano-integrated optics. In this
letter, we obtained femtosecond pulses with THz repetition frequency via the
strong coupling between quantum emitters (QEs) and plasmonic resonators. Our
structure consists of a V-groove (VG) plasmonic resonator and a nanowire
embedded with two-level QEs. The influences of the incident light intensity and
QE number density on the transmission response for this hybrid system are
investigated through semi-classical theory and simulation. It is found that the
transmission response can be modulated to the pulse form. The reason is the
strong coupling causes the output power of nanowire to behave as an oscillating
form, the oscillating output power in turn causes the field amplitude in the
resonator to oscillate over time. A feedback system is formed between the
plasmonic resonator and the QEs in nanowire. This provides a new method for
generating narrow pulsed lasers with ultrahigh repetition frequency in
plasmonic systems using a continous wave input, which has potential
applications in generating optical clock signals at the nanoscale.",1712.00958v3
2017-12-31,Resonance in modulation instability from non-instantaneous nonlinearities,"To explore resonance phenomena in the nonlinear region, we show by
experimental measurements and theoretical analyses that resonance happens in
modulation instability (MI) from non-instantaneous nonlinearities in
photorefractive crystals. With a temporally periodic modulation in the external
bias voltage, corresponding to a modulation in the nonlinear strength, an
enhancement in the visibility of MI at resonant frequency is reported through
spontaneous optical pattern formations. Modeled by such temporally periodic
nonlinear driving force to the system, theoretical curves obtained from a
nonlinear non-instantaneous Schr\""{o}dinger equation give good agreement to
experimental data. As MI is a universal signature of symmetry-breaking
phenomena, our observation on the resonance in MI may provide a control on
chaotic, solitary, and turbulence waves.",1801.00248v1
2018-06-11,Ab-initio wave-length dependent Raman spectra: Placzek approximation and beyond,"We analyze how to obtain non-resonant and resonant Raman spectra within the
Placzek as well as the Albrecht approximation. Both approximations are derived
from the matrix element for light scattering by application of the Kramers,
Heisenberg and Dirac formula. It is shown that the Placzek expression results
from a semi-classical approximation of the combined electronic and vibrational
transition energies. Molecular hydrogen, water and butadiene are studied as
test cases. It turns out that the Placzek approximation agrees qualitatively
with the more accurate Albrecht formulation even in the resonant regime for the
excitations of single vibrational quanta. However, multiple vibrational
excitations are absent in Placzek, but can be of similar intensities as single
excitations under resonance conditions. The Albrecht approximation takes
multiple vibrational excitations into account and the resulting simulated
spectra exhibit good agreement with experimental Raman spectra in the resonance
region as well.",1806.03840v2
2018-06-18,Marginally bound resonances of charged massive scalar fields in the background of a charged reflecting shell,"We study {\it analytically} the characteristic resonance spectrum of charged
massive scalar fields linearly coupled to a spherically symmetric charged
reflecting shell. In particular, we use analytical techniques in order to solve
the Klein-Gordon wave equation for the composed
charged-shell-charged-massive-scalar-field system. Interestingly, it is proved
that the resonant oscillation frequencies of this composed physical system are
determined by the characteristic zeroes of the confluent hypergeometric
function. Following this observation, we derive a remarkably compact analytical
formula for the resonant oscillation frequencies which characterize the
marginally-bound charged massive scalar field configurations. The analytically
derived resonance spectrum is confirmed by numerical computations.",1806.06831v1
2018-06-27,Resonance fluorescence from an atomic-quantum-memory compatible single photon source based on GaAs droplet quantum dots,"Single photon sources, which are compatible with quantum memories are an
important component of quantum networks. In this article, we show optical
investigations on isolated GaAs/Al$_{0.25}$Ga$_{0.75}$As quantum dots grown via
droplet epitaxy, which emit single photons on resonance with the Rb-87-D$_2$
line (780 nm). Under continuous wave resonant excitation conditions, we observe
bright, clean and narrowband resonance fluorescence emission from such a
droplet quantum dot. Furthermore, the second-order correlation measurement
clearly demonstrates the single photon emission from this resonantly driven
transition. Spectrally resolved resonance fluorescence of a similar quantum dot
yields a linewidth as narrow as 660 MHz ($ 2.7~\mu eV $), which corresponds to
a coherence time of 0.482 ns. The observed linewidth is the smallest reported
so far for strain free GaAs quantum dots grown via the droplet method. We
believe that this single photon source can be a prime candidate for
applications in optical quantum networks.",1806.10520v1
2018-09-09,Three-Body Problem of Bosons nearby a d-wave Resonance,"Motivated by recent experimental progresses, we investigate few-body
properties of interacting spinless bosons nearby a d-wave resonance. Using the
Skorniakov-Ter-Martirosion (STM) equations, we calculate the scattering length
between an atom and a d-wave dimer, and we find that the atom-dimer scattering
length is positive and is much smaller the result from the mean-field
approximation. We also reveal unique properties of the three-body recombination
rate for a degenerate Bose condensate nearby the d-wave resonance. We find that
the total recombination rate is nearly a constant at the quasi-bound side, in
contrast to the behavior of a thermal gas nearby high-partial wave resonance.
We also find that the recombination rate monotonically increases across the
unitary point toward the bound side, which is due to the largely enhanced
coupling between the atom and the d-wave dimer with deeper binding energy. This
monotonic behavior is also qualitatively different from that of a degenerate
gas nearby an s-wave resonance counterpart.",1809.03023v1
2019-11-09,Minnaert resonances for bubbles in soft elastic materials,"Minnaert resonance is a well known physical phenomenon and it has many
important applications, in particular in the effective realisation of acoustic
metamaterials using bubbly mediums in recent years. In this paper, motived by
the Minnaert resonance, we consider the low-frequency resonance for acoustic
bubbles embedded in soft elastic materials. This is a hybrid physical process
that couples the acoustic and elastic wave propagations. By delicately and
subtly balancing the acoustic and elastic parameters as well as the geometry of
the bubble, we show that Minnaert resonance can (approximately) occur for
rather general constructions. Our study poses a great potential for the
effective realisation of negative elastic materials by using bubbly elastic
mediums.",1911.03718v2
2019-11-13,Coupling Rydberg atoms to microwave fields in a superconducting coplanar waveguide resonator,"Rydberg helium atoms traveling in pulsed supersonic beams have been coupled
to microwave fields in a superconducting coplanar waveguide (CPW) resonator.
The atoms were initially prepared in the 1s55s $^3$S$_1$ Rydberg level by
two-color two-photon laser excitation from the metastable 1s2s $^3$S$_1$ level.
Two-photon microwave transitions between the 1s55s $^3$S$_1$ and 1s56s
$^3$S$_1$ levels were then driven by the 19.556 GHz third-harmonic microwave
field in a quarter-wave CPW resonator. This superconducting microwave resonator
was fabricated from niobium nitride on a silicon substrate and operated at
temperatures between 3.65 and 4.30 K. The populations of the Rydberg levels in
the experiments were determined by state-selective pulsed electric field
ionization. The coherence of the atom-resonator coupling was studied by
time-domain measurements of Rabi oscillations.",1911.05513v2
2012-09-08,Scale free networks of superconducting striped grains tuned at Fano resonances for high Tc,"Controlling lattice complexity or inhomogeneity of the doped oxide
superconductors is shown to be a key term for control of the superconductivity
critical temperature. All high temperature superconductors show anisotropic
gaps and/or multi-gap superconductivity in the clean limit. They show the shape
resonance in superconducting gaps that is a type of Fano resonance driven by
the Josephson-like term for pairs transfer. These resonances occur where one of
the multiple Fermi surface spots is near a 2.5 Lifshitz transition. The Fano
antiresonance occurs between a BCS condensate and a BEC-like condensate. In a
system near a 2.5 Lifshitz transition the lattice is close to an instability.
This drives to the formation of a granular superconducting phase made of a
charge density metal formed by puddles of ordered oxygen interstitials or
ordered local lattice distortions (static short range charge density waves)
detected by scanning nano-x-ray diffraction imaging. We show that the scale
free networks of superconducting grains tuned to a Fano resonance is an
essential feature of high temperature superconductors that favours high Tc.",1209.1723v1
2012-09-12,Double-resonant fast particle-wave interaction,"In future fusion devices fast particles must be well confined in order to
transfer their energy to the background plasma. Magnetohydrodynamic
instabilities like Toroidal Alfv\'en Eigenmodes or core-localized modes such as
Beta Induced Alfv\'en Eigenmodes and Reversed Shear Alfv\'en Eigenmodes, both
driven by fast particles, can lead to significant losses. This is observed in
many ASDEX Upgrade discharges. The present study applies the drift-kinetic
HAGIS code with the aim of understanding the underlying resonance mechanisms,
especially in the presence of multiple modes with different frequencies. Of
particular interest is the resonant interaction of particles simultaneously
with two different modes, referred to as 'double-resonance'. Various mode
overlapping scenarios with different q profiles are considered. It is found
that, depending on the radial mode distance, double-resonance is able to
enhance growth rates as well as mode amplitudes significantly. Surprisingly, no
radial mode overlap is necessary for this effect. Quite the contrary is found:
small radial mode distances can lead to strong nonlinear mode stabilization of
a linearly dominant mode.",1209.2549v1
2014-06-09,Graphene nanoelectromechanical resonators for detection of modulated terahertz radiation,"We propose and analyze the detector of modulated terahertz (THz) radiation
based on the graphene field-effect transistor with mechanically floating gate
made of graphene as well. The THz component of incoming radiation induces
resonant excitation of plasma oscillations in graphene layers (GLs). The
rectified component of the ponderomotive force between GLs invokes resonant
mechanical swinging of top GL, resulting in the drain current oscillations. To
estimate the device responsivity, we solve the hydrodynamic equations for the
electrons and holes in graphene governing the plasma-wave response, and the
equation describing the graphene membrane oscillations. The combined
plasma-mechanical resonance raises the current amplitude by up to four orders
of magnitude. The use of graphene as a material for the elastic gate and
conductive channel allows the voltage tuning of both resonant frequencies in a
wide range.",1406.2127v1
2016-03-05,Exploiting spatiotemporal degrees of freedom for far field subwavelength focusing using time reversal in fractals,"Materials which possess a high local density of states varying at a
subwavelength scale theoretically permit to focus waves onto focal spots much
smaller than the free space wavelength. To do so metamaterials -manmade
composite media exhibiting properties not available in nature- are usually
considered. However this approach is limited to narrow bandwidths due to their
resonant nature. Here, we prove that it is possible to use a fractal resonator
alongside time reversal to focus microwaves onto $\lambda/15$ subwavelength
focal spots from the far field, on extremely wide bandwidths. We first
numerically prove that this approach can be realized using a multiple channel
time reversal mirror, that utilizes all the degrees of freedom offered by the
fractal resonator. Then we experimentally demonstrate that this approach can be
drastically simplified by coupling the fractal resonator to a complex medium,
here a cavity, that efficiently converts its spatial degrees of freedom into
temporal ones. This allows to achieve deep subwavelength focusing of microwaves
using a single channel time reversal. Our method can be generalized to other
systems coupling complex media and fractal resonators.",1603.01725v1
2016-03-22,Reconstruction of annular bi-layered media in cylindrical waveguide section,"A radial transverse resonance model for two cylindrical concentric layers
with different complex dielectric constants is presented. An inverse problem
with four unknowns - 3 physical material parameters and one dimensional
dielectric layer thickness parameter- is solved by employing TE110 and TE210
modes with different radial field distribution. First a Newton-Raphson
algorithm is used to solve a least square problem with a Lorentzian function
(as resonance model and ""measured"" data generator). Then found resonance
frequencies and quality factors are used in a second inverse Newton-Raphson
algorithm that solves four transverse resonance equations in order to get four
unknown parameters. The use of TE110 and TE210 models offers one dimensional
radial tomographic capability. An open ended coax quarter-wave resonator is
added to the sensor topology, and the effect on the convergence is
investigated.",1603.06940v1
2016-12-05,Resonant transitions induced in particle processes by the non-perturbative treatment of strong laser fields,"Intense field quantum field theory (IFQFT) is used to determine new
phenomenological predictions arising from Compton scattering and pair
production in a strong laser field. This theory utilizes exact solutions of
fermions embedded in external plane waves which carry over to a strong field
fermion propagator. When these strong field fermions also interact with probe
photons, the transition probability is enhanced in a series of resonances when
the kinematics allow the virtual fermion to go on-shell. An analysis of
parameters shows that contemporary experiments could already produce these
predicted resonances. With appropriate tuning, resonances can be made
arbitrarily sharp, leading to precision calculations of resonance locations and
widths, and the runing of coupling constants in strong background fields. New
tests of QED could be performed leading to ramifications for our understanding
of the quantum vacuum. Such tests extend to QFT in background potentials in
general, which may throw light on BSM theories such as QFT in curved
space-times.",1612.09294v1
2017-02-09,Wavelength division multiplexed and double-port pumped time-bin entangled photon pair generation using Si ring resonator,"We report a wavelength division multiplexed time-bin entangled photon pair
source in telecom wavelength using a 10 {\mu}m radius Si ring resonator. This
compact resonator has two add ports and two drop ports. By pumping one add port
by a continuous laser, we demonstrate an efficient generation of two-wavelength
division multiplexed time-bin entangled photon pairs in the telecom C-band,
which come out of one drop port, and are then split into the signal and idler
photons via a wavelength filter. The resonator structure enhances four wave
mixing for pair generation. Moreover, we demonstrate the double-port pumping
where two counter propagating pump light are injected to generate entanglement
from the two drop ports simultaneously. We successfully observe the highly
entangled outputs from both two drop ports. Surprisingly, the count rate at
each drop port is even increased by twice as that of the single-port pumping.
Possible mechanisms of this observation are discussed. Our technique allows for
the efficient use of the Si ring resonator, and widens its functionality for
variety of applications.",1702.02659v1
2017-02-15,Analytical results regarding electrostatic resonances of surface phonon/plasmon polaritons: separation of variables with a twist,"The boundary integral equation method ascertains explicit relations between
localized surface phonon and plasmon polariton resonances and the eigenvalues
of its associated electrostatic operator. We show that group-theoretical
analysis of Laplace equation can be used to calculate the full set of
eigenvalues and eigenfunctions of the electrostatic operator for shapes and
shells described by separable coordinate systems. These results not only unify
and generalize many existing studies but also offer the opportunity to expand
the study of phenomena like cloaking by anomalous localized resonance. For that
reason we calculate the eigenvalues and eigenfunctions of elliptic and circular
cylinders. We illustrate the benefits of using the boundary integral equation
method to interpret recent experiments involving localized surface phonon
polariton resonances and the size scaling of plasmon resonances in graphene
nano-disks. Finally, symmetry-based operator analysis can be extended from
electrostatic to full-wave regime. Thus, bound states of light in the continuum
can be studied for shapes beyond spherical configurations.",1702.04655v1
2017-02-17,Understanding the importance of transient resonances in extreme mass ratio inspirals,"Extreme mass ratio inspirals (EMRIs) occur when a compact object orbits a
much larger one, like a solar-mass black hole around a supermassive black hole.
The orbit has 3 frequencies which evolve through the inspiral. If the orbital
radial frequency and polar frequency become commensurate, the system passes
through a transient resonance. Evolving through resonance causes a jump in the
evolution of the orbital parameters. We study these jumps and their impact on
EMRI gravitational-wave detection. Jumps are smaller for lower eccentricity
orbits; since most EMRIs have small eccentricities when passing through
resonances, we expect that the impact on detection will be small. Neglecting
the effects of transient resonances leads to a loss of ~4% of detectable
signals for an astrophysically motivated population of EMRIs.",1702.05481v1
2017-02-26,Fully coupled-channel complex scaling method for the $K^-pp$ system,"We have developed a fully coupled-channel complex scaling method (ccCSM) for
the study of the most essential kaonic nucleus, $``K^-pp,""$ which is a resonant
state of a $\bar{K}NN$-$\pi\Sigma N$-$\pi\Lambda N$ coupled-channel system
based on a theoretical viewpoint. By employing the ccCSM and imposing the
correct boundary condition of resonance, the coupled-channel problem is
completely solved using a phenomenological energy-independent potential. As a
result of the ccCSM calculation of $``K^-pp,""$ in which all three channels are
treated explicitly, we have obtained three-body resonance as a Gamow state. The
resonance pole indicates that the binding energy of $``K^-pp""$ and the half
value of its mesonic decay width are 51 MeV and 16 MeV, respectively. In the
analysis of the resonant wave function obtained using the ccCSM, we clarify the
spatial configuration and channel compositions of $``K^-pp.""$ Compared with
past studies of single-channel calculations based on effective $\bar{K}N$
potentials, the current study provides a guideline for the determination of the
$\bar{K}N$ energy to be used in effective potentials.",1702.08002v3
2017-06-30,Fano resonance via bonding and antibonding states in nonadiabatically-pumped double-quantum-well systems,"In this work, transport properties of the nonadiabatically pumped
double-quantum-well (DQW) structure are studied. Different from a single
quantum well, band mixing in the DQW generates bonding and antibonding states,
whose wave functions have different spatial symmetry. By applying a
time-dependent electric potential to the two well regions simultaneously,
Floquet sidebands are formed, which constitutes additional quantum tunneling
paths. When one of the Floquet sidebands coincides with the bonding or
antibonding quasibound states within the DQW structure, sharp Fano resonances
are found in the transmission coefficients as well as in the differential shot
noise spectra. While such Fano resonances originate from quantum interference,
their shapes are strikingly different for transport via the bonding state and
via the antibonding state. The Fano resonance via the even-parity bonding state
shows a perfect transmission followed by a total reflection and the Fano
resonance via the odd-parity antibonding state has a reversed symmetry and
shows a total reflection before a perfect transmission.",1706.10001v1
2017-10-09,Resonant absorption of surface sausage and surface kink modes under photospheric conditions,"We study the effect of resonant absorption of surface sausage and surface
kink modes under photospheric conditions where the slow surface sausage modes
undergo resonant damping in the slow continuum and the surface kink modes in
the slow and Alfv\'{e}n continua at the transitional layers. We use recently
derived analytical formulas to obtain the damping rate (time). By considering
linear density and linear pressure profiles for the transitional layers, we
show that resonant absorption in the slow continuum could be an efficient
mechanism for the wave damping of the slow surface sausage and slow surface
kink modes whilst the damping rate of the slow surface kink mode in the
Alfv\'{e}n continuum is weak. It is also found that the resonant damping of the
fast surface kink mode is much stronger than that of the slow surface kink
mode, showing a similar efficiency as under coronal conditions. It is worth to
notice that the slow body sausage and kink modes can also resonantly damp in
the slow continuum for those linear profiles.",1710.03350v2
2017-10-24,Functional meta-optics and nanophotonics govern by Mie resonances,"Scattering of electromagnetic waves by subwavelength objects is accompanied
by the excitation of electric and magnetic Mie resonances, that may modify
substantially the scattering intensity and radiation pattern. Scattered fields
can be decomposed into electric and magnetic multipoles, and the magnetic
multipoles define magnetic response of structured materials underpinning the
new field of all-dielectric resonant meta-optics. Here we review the recent
developments in meta-optics and nanophotonics, and demonstrate that the Mie
resonances can play a crucial role offering novel ways for the enhancement of
many optical effects near magnetic and electric multipolar resonances, as well
as driving a variety of interference phenomena which govern recently discovered
novel effects in nanophotonics. We further discuss the frontiers of
all-dielectric meta-optics for flexible and advanced control of light with full
phase and amplitude engineering, including nonlinear nanophotonics, anapole
nanolasers, quantum tomography, and topological photonics.",1710.08595v1
2019-03-24,Soliton and quasi-soliton frequency combs due to second harmonic generation in microresonators,"We report how a doublet of the symmetric oppositely tilted bistable resonance
peaks in a microring resonator with quadratic nonlinearity set for generation
of the second harmonic can transform into a Kerr-like peak on one side of the
linear cavity resonance and into a closed loop structure disconnected from the
quasi-linear resonance on the other. Both types of the nonlinear resonances are
associated with the formation of the soliton combs for dispersion profiles of a
typical LiNbO$_3$ microring. We report bright quasi-solitons propagating on a
weakly modulated low intensity background when the group velocity dispersions
have the opposite signs for the fundamental and second harmonic. We also show
exponentially localized solitons when the dispersion signs are the same.
Finally, we demonstrate that the transition between these two types of soliton
states is associated with the closure of the forbidden gap in the spectrum of
quasi-linear waves.",1903.09975v1
2019-05-05,Exceptional points for resonant states on parallel circular dielectric cylinders,"Exceptional points (EPs) are special parameter values of a non-Hermitian
eigenvalue problem where eigenfunctions corresponding to a multiple eigenvalue
coalesce. In optics, EPs are associated with a number of counter-intuitive wave
phenomena, and have potential applications in lasing, sensing, mode conversion
and spontaneous emission processes. For open photonic structures, resonant
states are complex-frequency solutions of the Maxwell's equations with outgoing
radiation conditions. For open dielectric structures without material gain or
loss, the eigenvalue problem for resonant states can have EPs, since it is
non-Hermitian due to radiation losses. For applications in nanophotonics, it is
important to understand EPs for resonant states on small finite dielectric
structures consisting of conventional dielectric materials. To achieve this
objective, we study EPs of resonant states on finite sets of parallel
infinitely-long circular dielectric cylinders with subwavelength radii. For
systems with two, three and four cylinders, we develop an efficient numerical
method for computing EPs, present examples for second and third order EPs, and
highlight their topological features. Our work provides insight to
understanding EPs on more complicated photonic structures, and can be used as a
simple platform to explore applications of EPs.",1905.01572v1
2019-05-12,Relation Between Solutions of the Schrödinger Equation with Transitioning Resonance Solutions of the Gravitational Three-Body Problem,"It is shown that a class of approximate resonance solutions in the three-body
problem under the Newtonian gravitational force are equivalent to quantized
solutions of a modified Schr\""odinger equation for a wide range of masses that
transition between energy states. In the macroscopic scale, the resonance
solutions are shown to transition from one resonance type to another through
weak capture at one of the bodies, while in the Schr\""odinger equation, one
obtains quantized wave solutions transitioning between different energies. The
resonance transition dynamics provides a classical model of a particle moving
between different energy states in the Schr\""odinger equation. This methodology
provides a connection between celestial and quantum mechanics.",1905.06705v2
2020-09-13,Nature of $\bm{S}$-wave $\bm{NN}$ interaction and dibaryon production at nucleonic resonance thresholds,"Phase shifts and inelasticity parameters for $NN$ scattering in the
partial-wave channels ${}^3S_1$--${}^3D_1$ and ${}^1S_0$ at energies $T_{\rm
lab}$ from zero to about 1 GeV are described within a unified $NN$ potential
model assuming the formation of isoscalar and isovector dibaryon resonances
near the $NN^*(1440)$ threshold. Evidence for these near-threshold resonances
is actually found in the recent WASA experiments on single- and double-pion
production in $NN$ collisions. There, the excitation of the Roper resonance
$N^*(1440)$ exhibits a structure in the energy dependence of the total cross
section, which corresponds to the formation of dibaryon states with
$I(J^\pi)=0(1^+)$ and $1(0^+)$ at the $NN^*(1440)$ threshold. These two
$S$-wave dibaryon resonances may provide a new insight into the nature of the
strong $NN$ interaction at low and intermediate energies.",2009.05941v1
2021-02-04,Dissipative stabilization of squeezing beyond 3 dB in a microwave mode,"While a propagating state of light can be generated with arbitrary squeezing
by pumping a parametric resonator, the intra-resonator state is limited to 3 dB
of squeezing. Here, we implement a reservoir engineering method to surpass this
limit using superconducting circuits. Two-tone pumping of a three-wave-mixing
element implements an effective coupling to a squeezed bath which stabilizes a
squeezed state inside the resonator. Using an ancillary superconducting qubit
as a probe allows us to perform a direct Wigner tomography of the
intra-resonator state. The raw measurement provides a lower bound on the
squeezing at about $6.7 \pm 0.2$ dB below the zero-point level. Further, we
show how to correct for resonator evolution during the Wigner tomography and
obtain a squeezing as high as $8.2 \pm 0.8$ dB. Moreover, this level of
squeezing is achieved with a purity of $-0.4 \pm 0.4$ dB.",2102.02863v2
2021-02-17,Space-time resonances and high-frequency Raman instabilities in the two-fluid Euler-Maxwell system,"We show that space-time resonances induce high-frequency Raman instabilities
in the two-fluid Euler-Maxwell system describing laser-plasma interactions. A
consequence is that the Zakharov WKB approximation to Euler-Maxwell is unstable
for non-zero group velocities. A key step in the proof is the reformulation of
the set of resonant frequencies as the locus of weak hyperbolicity for
linearized equations around the WKB solution. We analyze those linearized
equations with the symbolic flow method. Due to large transverse variations in
the WKB profile, the equation satisfied by the symbolic flow around resonant
frequencies is a linear {\it partial} differential equation. At space-time
resonances corresponding to Raman instabilities, we observe a fast growth of
the symbolic flow, which translates into an instability result for the original
system. The strongest instability is caused by backscattered Raman waves.",2102.08891v1
2021-10-04,Anomalous temperature dependence of phonon pumping by ferromagnetic resonance in Co/Pd multilayers with perpendicular anisotropy,"We demonstrate the pumping of phonons by ferromagnetic resonance in a series
of [Co(0.8 nm)/Pd(1.5 nm)]$_n$ multilayers ($n =$ 6, 11, 15, and 20) with large
magnetostriction and perpendicular magnetic anisotropy. The effect is shown
using broadband ferromagnetic resonance over a range of temperatures (10 to 300
K), where a resonant damping enhancement is observed at frequencies
corresponding to standing wave phonons across the multilayer. The strength of
this effect is enhanced by approximately a factor of 4 at 10 K compared to room
temperature, which is anomalous in the sense that the temperature dependence of
the magnetostriction predicts an enhancement that is less than a factor of 2.
Lastly, we demonstrate that the damping enhancement is correlated with a shift
in the ferromagnetic resonance field as predicted quantitatively from linear
response theory.",2110.01714v1
2017-01-31,Switchable invisibility of dielectric resonators,"The study of invisibility of an infinite dielectric rod with high refractive
index is based on the two-dimensional Mie scattering problem, and it suggests
strong suppression of scattering due to the Fano interference between
spectrally broad nonresonant waves and narrow Mie-resonant modes. However, when
the dielectric rod has a finite extension, it becomes a resonator supporting
the Fabry-Perot modes which introduce additional scattering and eventually
destroy the invisibility. Here we reveal that for shorter rods with modest
values of the aspect ratio r/L (where r and L are the radius and length of the
rod, respectively), the lowest spectral window of the scattering suppression
recovers completely, so that even a finite-size resonator may become invisible.
We present a direct experimental verification of the concept of switchable
invisibility at microwaves using a cylindrical finite-size resonator with high
refractive index.",1701.09022v1
2019-01-25,A fully-coupled subwavelength resonance approach to modelling the passive cochlea,"The aim of this paper is to understand the behaviour of a large number of
coupled subwavelength resonators. We use layer potential techniques in
combination with numerical computations to study the acoustic pressure field
due to scattering by a graded array of subwavelength resonators. Using this
method, we study a graded-resonance model for the cochlea. We compute the
resonant modes of the system and explore the model's ability to decompose
incoming signals. We are able to offer mathematical explanations for the
cochlea's so-called ""travelling wave"" behaviour and tonotopic frequency map.",1901.08808v4
2019-04-15,Photonic-crystal-reflector nano-resonators for Kerr-frequency combs,"We demonstrate Kerr-frequency-comb generation with nanofabricated Fabry-Perot
resonators with photonic-crystal-reflector (PCR) end mirrors. The PCR
group-velocity-dispersion (GVD) is engineered to counteract the strong normal
GVD of a rectangular waveguide fabricated on a thin, 450 nm silicon nitride
device layer. The reflectors provide the resonators with both the high optical
quality factor and anomalous GVD required for Kerr-comb generation. We report
design, fabrication, and characterization of devices in the 1550 nm wavelengths
bands, including the GVD spectrum and quality factor. Kerr-comb generation is
achieved by exciting the devices with a continuous-wave (CW) laser. The
versatility of PCRs enables a general design principle and a
material-independent device infrastructure for Kerr-nonlinear-resonator
processes, opening new possibilities for manipulation of light. Visible and
multi-spectral-band resonators appear to be natural extensions of the PCR
approach.",1904.07289v2
2019-07-09,Studies of the resonance components in the $B_s$ decays into charmonia plus kaon pair,"In this work, the decays of $B_s$ mesons to a charmonium state and a $K^+K^-$
pair are carefully investigated in the perturbative QCD approach. Following the
latest fit from the LHCb experiment, we restrict ourselves to the case where
the produced $K^+K^-$ pair interact in isospin zero $S$, $P$, and $D$ wave
resonances in the kinematically allowed mass window. Besides the dominant
contributions of the $\phi(1020)$ resonance in the $P$-wave and $f_2'(1525)$ in
the $D$-wave, other resonant structures in the high mass region as well as the
$S$-wave components are also included. The invariant mass spectra for most of
the resonances in the $B_s\rightarrow J/\psi K^+K^-$ decay are well reproduced.
The obtained three-body decay branching ratios can reach the order of
$10^{-4}$, which seem to be accessible in the near future experiments. The
associated polarization fractions of those vector-vector and vector-tensor
modes are also predicted, which are compared with the existing data from LHCb
Collaboration.",1907.04128v2
2019-09-18,Gain-through-filtering enables tuneable frequency comb generation in passive optical resonators,"Optical frequency combs (OFCs), consisting of a set of phase locked equally
spaced laser frequency lines, have enabled a great leap in precision
spectroscopy and metrology since seminal works of H\""ansch et al. . Nowadays,
OFCs are cornerstones of a wealth of further applications ranging from
chemistry and biology to astrophysics and including molecular fingerprinting
and LIDARs among others. Driven passive optical resonators constitute the ideal
platform for OFCs generation in terms of compactness and low energy footprint.
We propose here a new technique for generation of OFCs with tuneable repetition
rate in externally driven optical resonators based on the
gain-through-filtering process, a simple and elegant method, due to an
asymmetric spectral filtering on one side of the pump wave. We demonstrate a
proof-of-concept experimental result in a fibre resonator, pioneering a new
technique that does not require specific engineering of the resonator
dispersion to generate frequency agile OFCs.",1909.08294v2
2019-09-26,Polar metamaterials: A new outlook on resonance for cloaking applications,"Rotationally resonant metamaterials are leveraged to answer a longstanding
question regarding the existence of transformation-invariant elastic materials
and the ad-hoc possibility of transformationbased passive cloaking in full
plane elastodynamics. Combined with tailored lattice geometries, rotational
resonance is found to induce a polar and chiral behavior; that is a behavior
lacking stress and mirror symmetries, respectively. The central, and simple,
idea is that a population of rotating resonators can exert a density of body
torques strong enough to modify the balance of angular momentum on which hang
these symmetries. The obtained polar metamaterials are used as building blocks
of a cloaking device. Numerical tests show satisfactory cloaking performance
under pressure and shear probing waves, further coupled through a free
boundary. The work sheds new light on the phenomenon of resonance in
metamaterials and should help put transformation elastodynamics on equal
footing with transformation acoustics and optics.",1909.12437v1
2019-10-16,Searching for scalar dark matter with compact mechanical resonators,"We explore the viability of laboratory-scale mechanical resonators as
detectors for ultralight scalar dark matter. The signal we investigate is an
atomic strain due to modulation of the fine structure constant and the lepton
mass at the Compton frequency of dark matter particles. The resulting stress
can drive an elastic body with acoustic breathing modes, producing
displacements that are accessible with opto- or electromechanical readout
techniques. To address the unknown mass of dark matter particles (which
determines their Compton frequency), we consider various resonator designs
operating at kHz to MHz frequencies, corresponding to $10^{-12}-10^{-5}$ eV
particle mass. Current resonant-mass gravitational wave detectors that have
been repurposed as dark matter detectors weigh $\sim \! 10^3$ kg. We find that
a large unexplored parameter space can be accessed with ultra-high-$Q$,
cryogenically-cooled, cm-scale mechanical resonators possessing $\sim \! 10^7$
times smaller mass.",1910.07574v2
2019-12-10,Probabilistic motional averaging,"In a continuous measurement scheme a spin-1/2 particle can be measured and
simultaneously driven by an external resonant signal. When the driving is weak,
it does not prevent the particle wave-function from collapsing and a detector
randomly outputs two responses corresponding to the states of the particle. In
contrast, when driving is strong, the detector returns a single response
corresponding to the mean of the two single-state responses. This situation is
similar to a motional averaging, observed in nuclear magnetic resonance
spectroscopy. We study such quantum system, being periodically driven and
probed, which consists of a qubit coupled to a quantum resonator. It is
demonstrated that the transmission through the resonator is defined by the
interplay between driving strength, qubit dissipation, and resonator linewidth.
We demonstrate that our experimental results are in good agreement with
numerical and analytical calculations.",1912.04557v1
2020-01-24,Suppressed-gap millimetre wave kinetic inductance detectors using DC-bias current,"In this study, we evaluate the suitability of using DC-biased aluminium
resonators as low-frequency kinetic inductance detectors operating in the
frequency range of 50 - 120 GHz. Our analysis routine for supercurrent-biased
resonators is based on the Usadel equations and gives outputs including density
of states, complex conductivities, transmission line properties, and
quasiparticle lifetimes. Results from our analysis confirm previous
experimental observations on resonant frequency tuneability and retention of
high quality factor. Crucially, our analysis suggests that DC-biased resonators
demonstrate significantly suppressed superconducting density of states gap.
Consequently these resonators have lower frequency detection threshold and are
suitable materials for low-frequency kinetic inductance detectors.",2001.09089v2
2020-01-28,Enhancement of deep-subwavelength band gaps in flat spiral-based phononic metasurfaces using the trampoline phenomena,"Elastic and acoustic metamaterials can sculpt dispersion of waves through
resonances. In turn, resonances can give rise to negative effective properties,
usually localized around the resonance frequencies, which support band gaps at
subwavelength frequencies (i.e., below the Bragg-scattering limit). However,
the band gaps width correlates strongly with the resonators' mass and volume,
which limits their functionality in applications. Trampoline phenomena have
been numerically and experimentally shown to broaden the operational frequency
ranges of two-dimensional, pillar-based metamaterials through perforation. In
this work, we demonstrate trampoline phenomena in lightweight and planar
lattices consisting of arrays of Archimedean spirals in unit cells.
Spiral-based metamaterials have been shown to support different band gap
opening mechanisms, namely, Bragg-scattering, local resonances and inertia
amplification. Here, we numerically analyze and experimentally realize
trampoline phenomena in planar metasurfaces for different lattice
tessellations. Finally, we carry out a comparative study between trampoline
pillars and spirals and show that trampoline spirals outperform the pillars in
lightweight, compactness and operational bandwidth.",2001.10508v1
2020-02-02,Virtual Critical Coupling,"Electromagnetic resonators are a versatile platform to harvest, filter and
trap electromagnetic energy, at the basis of many applications from microwaves
to optics. Resonators with a large intrinsic quality factor (Q) are highly
desirable since they can store a large amount of energy, leading to sharp
filtering and low loss. Exciting high-Q cavities with monochromatic signals,
however, suffers from poor excitation efficiency, i.e., most of the impinging
energy is lost in the form of reflection, since high-Q resonators are weakly
coupled to external radiation. Although critical coupling eliminates
reflections in steady-state by matching the intrinsic and coupling decay rates,
this approach requires the introduction of loss in the resonator, causing
dissipation and lowering the overall Q-factor. Here, we extend the notion of
critical coupling to high-Q lossless resonators based on tailoring the temporal
profile of the excitation wave. Utilizing coupled-mode theory, we demonstrate
an effect analogous to critical coupling by mimicking loss with
non-monochromatic excitations at complex frequencies. Remarkably, we show that
this approach enables unitary excitation efficiency in open systems, even in
the limit of extreme quality factors in the regime of quasi-bound states in the
continuum.",2002.00487v1
2020-02-11,Resonant scattering of Dice quasiparticles on oscillating quantum dots,"We consider a Dice model with Dirac cones intersected by a topologically flat
band at the charge neutrality point and analyze the inelastic scattering of
massless pseudospin-1 particles on a circular, gate-defined, oscillating
barrier. Focusing on the resonant scattering regime at small energy of the
incident wave, we calculate the reflection and transmission coefficients and
derive explicit expressions for the time-dependent particle probability,
current density and scattering efficiency within (Floquet) Dirac-Weyl theory,
both in the near-field and the far-field. We discuss the importance of sideband
scattering and Fano resonances in the quantum limit. When resonance conditions
are fulfilled, the particle is temporarily trapped in vortices located close to
edge of the quantum dot before it gets resubmitted with strong angular
dependence. Interestingly even periodically alternating forward and backward
radiation may occur. We also demonstrate the revival of resonant scattering
related to specific fusiform boundary trapping profiles.",2002.04659v1
2021-05-03,Acoustic passive cloaking using thin outer resonators,"We consider the propagation of acoustic waves in a 2D waveguide unbounded in
one direction and containing a compact obstacle. The wavenumber is fixed so
that only one mode can propagate. The goal of this work is to propose a method
to cloak the obstacle. More precisely, we add to the geometry thin outer
resonators of width $\varepsilon$ and we explain how to choose their positions
as well as their lengths to get a transmission coefficient approximately equal
to one as if there were no obstacle. In the process we also investigate several
related problems. In particular, we explain how to get zero transmission and
how to design phase shifters. The approach is based on asymptotic analysis in
presence of thin resonators. An essential point is that we work around
resonance lengths of the resonators. This allows us to obtain effects of order
one with geometrical perturbations of width $\varepsilon$. Various numerical
experiments illustrate the theory.",2105.00922v1
2022-01-30,Port Reconfigurable Phase-Change Optical Resonator,"Active control and manipulation of electromagnetic waves are highly desirable
for advanced photonic device technology, such as optical cloaking, active
camouflage and information processing. Designing optical resonators with high
ease-of-control and reconfigurability remains a open challenge thus far. Here
we propose a novel mechanism to continuously reconfigure an optical resonator
between one-port and two-port configurations via \emph{phase-change material}
for efficient optical modulation. By incorporating a phase-change material
VO$_2$ substrate into a photonic crystal optical resonator, we computationally
show that the system behaves as a one-port device with near-perfect absorption
and two-port device with high transmission up to 92% when VO$_2$ is in the
metallic rutile phase and insulating monoclinic phase, respectively. The
optical response can be continuously and reversibly modulated between various
intermediate states. More importantly, the proposed device is compatible with
wide-angle operation and is robust against structural distortion. Our findings
reveal a novel device architecture of \emph{port reconfigurable} optical
resonator uniquely enabled by switchable optical properties of phase change
material.",2201.12800v1
2022-02-01,Pion axioproduction: The Delta resonance contribution,"The process of pion axioproduction, $aN\to\pi N$, with an intermediate
$\Delta$ resonance is analyzed using baryon chiral parturbation theory. The
$\Delta$ resonance is included in two ways: First, deriving the $a\Delta
N$-vertices, the axion is brought into contact with the resonance, and, second,
taking the results of $\pi N$ elastic scattering including the $\Delta$, it is
implicitly included in the form of a pion rescattering diagram. As a result,
the partial wave cross section of axion-nucleon scattering shows an enhancement
in the energy region around the $\Delta$ resonance. Because of the isospin
breaking, the enhancement is not as pronounced as previously anticipated.
However, since the isospin breaking here is much milder than that for usual
hadronic processes, novel axion search experiments might still exploit this
effect.",2202.00268v2
2022-03-01,Determination of atomic multiphoton ionization phases by trichromatic multichannel wave packet interferometry,"We present a multichannel photoelectron interferometry technique based on
trichromatic pulse shaping for unambiguous determination of quantum phases in
multiphoton ionization (MPI) of potassium atoms. The colors of the laser field
are chosen to produce three energetically separated photoelectron
interferograms in the continuum. While the red pulse is two-photon resonant
with the $3d$-state resulting in a (2+1) resonance-enhanced MPI (REMPI), a
(1+2) REMPI occurs via the non-resonant intermediate $4p$-state with an initial
green or blue pulse. We show that ionization via a non-resonant intermediate
state lifts the degeneracy of photoelectron interferograms from pathways
consisting of permutations of the colors. The analysis of the interferograms
reveals a phase shift of $\pm \pi/2$ depending on the sign of the detunings in
the (1+2) REMPI pathways. In addition, we demonstrate that the photoionization
time delay in the resonant (2+1) REMPI pathway gives rise to a linear spectral
phase in the photoelectron spectra. Insights into the underlying MPI processes
are gained through an analytic perturbative description and numerical
simulations of a trichromatic driven three level system coupled to the
continuum.",2203.00323v2
2022-03-21,Computation of eigenfrequency sensitivities using Riesz projections for efficient optimization of nanophotonic resonators,"Resonances are omnipresent in physics and essential for the description of
wave phenomena. We present an approach for computing eigenfrequency
sensitivities of resonances. The theory is based on Riesz projections and the
approach can be applied to compute partial derivatives of the complex
eigenfrequencies of any resonance problem. Here, the method is derived for
Maxwell's equations. Its numerical realization essentially relies on direct
differentiation of scattering problems. We use a numerical implementation to
demonstrate the performance of the approach compared to differentiation using
finite differences. The method is applied for the efficient optimization of the
quality factor of a nanophotonic resonator.",2203.11101v2
2022-06-22,Neolithic stone settlements as locally resonant metasurfaces,"We study the dynamic surface response of neolithic stone settlements obtained
with seismic ambient noise techniques near the city of Carnac in French
Brittany. Surprisingly, we find that menhirs (neolithic human size standing
alone granite stones) with an aspect ratio between 1 and 2 periodically
arranged atop a thin layer of sandy soil laid on a granite bedrock, exhibit
fundamental resonances in the range of 10 to 25 Hz. We propose an analogic
Kelvin-Voigt viscoelastic model that explains the origin of such low frequency
resonances. We further explore low frequency filtering effect with full wave
finite element simulations. Our numerical results confirm the bending nature of
fundamental resonances of the menhirs and further suggest additional resonances
of rotational and longitudinal nature in the frequency range 25 to 50 Hz. Our
study thus paves the way for large scale seismic metasurfaces consisting of
granite stones periodically arranged atop a thin layer of regolith over a
bedrock, for ground vibration mitigation in earthquake engineering.",2206.10825v1
2022-12-26,On phase at a resonance in slow-fast Hamiltonian systems,"We consider a slow-fast Hamiltonian system with one fast angular variable (a
fast phase) whose frequency vanishes on some surface in the space of slow
variables (a resonant surface). Systems of such form appear in the study of
dynamics of charged particles in inhomogeneous magnetic field under influence
of a high-frequency electrostatic waves. Trajectories of the averaged over the
fast phase system cross the resonant surface. The fast phase makes $\sim \frac
{1}{\varepsilon}$ turns before arrival to the resonant surface ($\varepsilon$
is a small parameter of the problem). An asymptotic formula for the value of
the phase at the arrival to the resonance was derived earlier in the context of
study of charged particle dynamics on the basis of heuristic considerations
without any estimates of its accuracy. We provide a rigorous derivation of this
formula and prove that its accuracy is $O(\sqrt \varepsilon)$ (up to a
logarithmic correction). Numerics indicate that this estimate for the accuracy
is optimal.",2212.13293v1
2023-04-03,Improved constraints on minimum length models with a macroscopic low loss phonon cavity,"Many theories that attempt to formulate a quantum description of gravity
suggest the existence of a fundamental minimum length scale. A popular method
for incorporating this minimum length is through a modification of the
Heisenberg uncertainty principle known as the generalised uncertainty principle
(GUP). Experimental tests of the GUP applied to composite systems can be
performed by searching for the induced frequency perturbations of the modes of
mechanical resonators, thus constraining the degree of minimum length in
certain scenarios. In this work previous constraints made with mechanical
resonators are improved upon by three orders of magnitude, via the utilisation
of a cryogenic quartz bulk acoustic wave resonator. As well as purely
mechanical resonant modes; hybrid electromechanical anti-resonant modes are
investigated, and shown to be sensitive to the same GUP induced effects.",2304.00688v2
2023-04-09,Beyond 5 GHz excitation of a ZnO-based high-overtone bulk acoustic resonator on SiC substrate,"This work describes the fabrication and characterization of an
Au/ZnO/Pt-based high-overtone bulk acoustic resonator (HBAR) on SiC substrates.
We evaluate its microwave characteristics comparing with Si substrates for
micro-electromechanical applications. Dielectric magnetron sputtering and an
electron beam evaporator are employed to develop highly c-axis-oriented ZnO
films and metal electrodes. The crystal structure and surface morphology of
post-growth layers have been characterized using X-ray diffraction (XRD),
atomic force microscopy (AFM), and scanning electron microscopy (SEM)
techniques. HBAR on SiC substrate results in multiple longitudinal bulk
acoustic wave resonances up to 7 GHz, with the strongest excited resonances
emerging at 5.25 GHz. The value of f.Q (Resonance frequency * Quality factor)
parameter obtained using a novel Q approach method for HBAR on SiC substrate is
4.1 * 10^13 Hz which, to the best of our knowledge, is the highest among all
reported values for specified ZnO-based devices.",2304.04286v1
2023-09-21,Simultaneous Resonant and Broadband Detection for Dark Sectors,"Electromagnetic resonant systems, such as cavities or LC circuits, have
emerged as powerful detectors for probing ultralight boson dark matter and
high-frequency gravitational waves. However, the limited resonant bandwidth of
conventional single-mode resonators, imposed by quantum fluctuations,
necessitates numerous scan steps to cover broad unexplored frequency regions.
The incorporation of multiple auxiliary modes can realize a broadband detector
while maintaining a substantial signal response. The broadened sensitive width
can be on the same order as the resonant frequency, encompassing several orders
of the source frequency for heterodyne detection, where a background cavity
mode transitions into another. Consequently, our approach enables significantly
deeper exploration of the parameter space within the same integration time
compared to single-mode detection.",2309.12387v1
2024-01-08,Room-Temperature Plasmon-Assisted Resonant THz Detection in Single-layer Graphene Transistors,"Frequency-selective or even frequency-tunable Terahertz (THz) photodevices
are critical components for many technological applications that require
nanoscale manipulation, control and confinement of light. Within this context,
gate-tunable phototransistors based on plasmonic resonances are often regarded
as the most promising devices for frequency-selective detection of THz fields.
The exploitation of constructive interference of plasma waves in such detectors
not only promises frequency selectivity, but also a pronounced sensitivity
enhancement at the target frequencies. However, clear signatures of
plasmon-assisted resonances in THz detectors have been only revealed at
cryogenic temperatures so far, and remain unobserved at application-relevant
room-temperature conditions. In this work, we demonstrate the sought-after
room-temperature resonant detection of THz radiation in short-channel gated
photodetectors made from high-quality single-layer graphene. The survival of
this intriguing resonant regime at room-temperature ultimately relies on the
weak intrinsic electron-phonon scattering in graphene, which avoids the damping
of the plasma oscillations.",2401.04005v1
2024-02-08,Extinction of guided light induced by coupled spiral meta-atom resonators at arbitrary order exceptional points,"Exceptional points (EPs) in non-Hermitian systems can give rise to intriguing
effects not available in conventional Hermitian systems due to their unusual
properties. Using full-wave simulations, we investigate the scattering,
absorption, and transmission of guided light at arbitrary order exceptional
points in a non-Hermitian system consisting of coupled spiral meta-atom
resonators sitting on a dielectric waveguide. The EPs are realized by
exploiting the unidirectional coupling of the chiral dipole modes in the
subwavelength meta-atom resonators. The scattering and absorption of the
resonators induce the attenuation of the guided light in the dielectric
waveguide. We show that the EPs can give rise to a plateau in the attenuation
spectrum of the guided light with near-zero transmission, i.e., the guided
light is almost completely dissipated via the resonators in the forms of
intrinsic material loss and radiation loss. In addition, the width of this
plateau (i.e., the extinction bandwidth) increases with the order of the EP.
The phenomena can be understood by employing a coupled mode analysis, with the
analytical results quantitatively agree with the numerical results. The results
may find applications in designing novel on-chip optical absorbers and sensors.",2402.06686v1
1999-08-24,Spin Dynamics of Rare Earth Ions in Phosphate Laser Glasses,"The spin dynamics of rare earth ions (Er, Nd, Sm and Gd) in heavily doped
phosphate glasses have been investigated using 31P NMR. Correlation times in
the range 10^-2 to 10^-12 s have been obtained for temperatures between 4 K and
100 K. No evidence of spin-spin coupling between the ions has been found and
spin relaxation occurs via conventional phonon processes, including the Orbach
process.
  A model involving inhomogeneous broadening of the NMR resonance lines, with
distinct sample regions corresponding to the presence or absence of nuclear
spin diffusion, has been used in extracting the electron spin correlation times
from the NMR measurements.",9908333v1
2000-07-25,Spin-lattice relaxation in the mixed state of the high-$T_c$ cuprates: electronic spin-flip scattering versus spin-fluctuations,"Recent experimental and theoretical studies have established that the
spin-lattice relaxation rate, $1/T_1$, measured in nuclear magnetic resonance
(NMR) experiments is a site-sensitive probe for the electronic spectrum in the
mixed state of the high-$T_c$ cuprates. While some groups suggested that
$1/T_1$ is solely determined by spin-flip scattering of BCS-like electrons,
other groups stressed the importance of antiferromagnetic spin-fluctuations. We
show that these two relaxation mechanisms give rise to a {\it qualitatively}
different temperature and frequency dependence of $^{17}$O $1/T_1$. A
comparison of our results with the experimental $^{17}$O $1/T_1$ data provides
support for a relaxation mechanism dominated by antiferromagnetic
spin-fluctuations.",0007393v1
2001-07-10,Cu NQR study of host and guest spin dynamics in impurity-doped YBa2Cu4O8,"We present the planar 63Cu nuclear spin-lattice relaxation study of
impurity-doped YBa2(Cu1-xMx)4O8 (M=Ni, Zn) at T=4.2-300 K with Cu nuclear
quadrupole resonance (NQR) spin-echo technique. In the light of an
impurity-induced NQR relaxation theory, we estimated the host Cu nuclear
spin-lattice relaxation time (T1)HOST, the impurity-induced Cu nuclear
spin-lattice relaxation time (t1), and the wipeout region around the impurity
in the superconducting state. The pseudo spin-gap behavior of the host Cu
antiferromagnetic spin fluctuation above Tc is not readily removed by a small
amount of the impurity. The Zn-induced non-Korringa behavior of (T1)HOST below
Tc is in sharp contrast to the doping effect of the magnetic impurity Ni.",0107186v1
2002-09-24,Nonequilibrium spin fluctuations in single-electron transistors,"We show that nonequilibrium spin fluctuations significantly influence the
electronic transport in a single-electron transistor, when the spin relaxation
on the island is slow compared to other relaxation processes, and when size
effects play a role. To describe spin fluctuations we generalize the `orthodox'
tunneling theory to take into account the electron spin, and show that the
transition between consecutive charge states can occur via a high-spin state.
This significantly modifies the shape of Coulomb steps and gives rise to
additional resonances at low temperatures. Recently some of our predictions
were confirmed by Fujisawa et al. [Phys. Rev. Lett. 88, 236802 (2002)], who
demonstrated experimentally the importance of nonequilibrum spin fluctuations
in transport through quantum dots.",0209559v1
2003-02-24,Detection of electrical spin injection by light-emitting diodes in top- and side-emission configuration,"Detection of the degree of circular polarization of the electroluminescence
of a light-emitting diode fitted with a spin injecting contact (a spin-LED)
allows for a direct determination of the spin polarization of the injected
carriers. Here, we compare the detection efficiency of (Al,Ga)As spin-LEDs
fitted with a (Zn,Be,Mn)Se spin injector in top- and side-emission
configuration. In contrast with top emission, we cannot detect the electrical
spin injection in side emission from analysing the degree of circular
polarization of the electroluminescence. To reduce resonant optical pumping of
quantum-well excitons in the side emission, we have analysed structures with
mesa sizes as small as 1 micron.",0302477v1
2004-01-03,Spin-lattice relaxation rate of a magnetic impurity in the spin degenerate Anderson model,"The renormalization group formalism was applied to calculate the spin-lattice
relaxation rate of a well-defined magnetic moment in the neighborhood of a spin
degenerate Anderson impurity. In the Kondo regime, the spin-lattice relaxation
rate as a function of the temperature presents a peak at the Kondo temperature;
for temperature much lower then the Kondo temperature, the system behaves as a
heavy Fermy liquid, with an enhanced density of states, which increases with
the decreasing of the Kondo temperature; the product of the temperature by the
relaxation rate remains an universal function of the temperature, which is
scaled by the Kondo resonance width, up to temperatures of the order of one
hundred of this width; for temperatures lower then the Kondo temperature, the
spin-lattice relaxation rate is proportional to the magnetic susceptibility
multiplied by the temperature; the peak of spin-lattice relaxation at the Kondo
temperature decreases with the increasing of the distance between the Anderson
impurity and the magnetic probe.",0401022v1
2005-05-02,Absence of spin superradiance in resonatorless magnets,"A spin system is considered with a Hamiltonian typical of molecular magnets,
having dipole-dipole interactions and a single-site magnetic anisotropy. In
addition, spin interactions through the common radiation field are included. A
fully quantum-mechanical derivation of the collective radiation rate is
presented. An effective narrowing of the dipole-dipole attenuation, due to high
spin polarization is taken into account. The influence of the radiation rate on
spin dynamics is carefully analysed. It is shown that this influence is
completely negligible. No noticeable collective effects, such as superradiance,
can appear in molecular magnets, being caused by electromagnetic spin
radiation. Spin superradiance can arise in molecular magnets only when these
are coupled to a resonant electric circuit, as has been suggested earlier by
one of the authors in Laser Phys. {\bf 12}, 1089 (2002).",0505024v1
2006-05-08,"Spin-orbit effects in GaAs quantum wells: Interplay between Rashba, Dresselhaus, and Zeeman interactions","The interplay between Rashba, Dresselhaus and Zeeman interactions in a
quantum well submitted to an external magnetic field is studied by means of an
accurate analytical solution of the Hamiltonian, including electron-electron
interactions in a sum rule approach. This solution allows to discuss the
influence of the spin-orbit coupling on some relevant quantities that have been
measured in inelastic light scattering and electron-spin resonance experiments
on quantum wells. In particular, we have evaluated the spin-orbit contribution
to the spin splitting of the Landau levels and to the splitting of charge- and
spin-density excitations. We also discuss how the spin-orbit effects change if
the applied magnetic field is tilted with respect to the direction
perpendicular to the quantum well.",0605199v1
2006-10-17,The spin state transition in LaCoO$_{3}$; revising a revision,"Using soft x-ray absorption spectroscopy and magnetic circular dichroism at
the Co-$L_{2,3}$ edge we reveal that the spin state transition in LaCoO$_{3}$
can be well described by a low-spin ground state and a triply-degenerate
high-spin first excited state. From the temperature dependence of the spectral
lineshapes we find that LaCoO$_{3}$ at finite temperatures is an inhomogeneous
mixed-spin-state system. Crucial is that the magnetic circular dichroism signal
in the paramagnetic state carries a large orbital momentum. This directly shows
that the currently accepted low-/intermediate-spin picture is at variance.
Parameters derived from these spectroscopies fully explain existing magnetic
susceptibility, electron spin resonance and inelastic neutron data.",0610457v1
2007-01-15,Decoherence induced by anisotropic hyperfine interaction in Si spin qubits,"We study Si:P donor electron spin decoherence due to anisotropic hyperfine
(AHF) interaction with the surrounding nuclear spin bath. In particular, we
clarify the electron spin echo envelope modulation (ESEEM) in the Si:P system
and the resonancelike contributions from nuclear spins in various shells away
from the P atoms. We suggest an approach to minimize AHF-induced decoherence by
avoiding the resonances and orienting an applied magnetic field along
directions that can periodically eliminate contributions from the dominant
nearest neighbor atoms. Our remarkable agreement with experiment demonstrates
nearly complete understanding of electron spin decoherence in Si:P when
combining ESEEM, spectral diffusion, instantaneous diffusion, and spin-lattice
relaxation.",0701341v2
2004-09-12,Energy levels and decoherence properties of single electron and nuclear spins in a defect center in diamond,"The coherent behavior of the single electron and single nuclear spins of a
defect center in diamond and a 13C nucleus in its vicinity, respectively, are
investigated. The energy levels associated with the hyperfine coupling of the
electron spin of the defect center to the 13C nuclear spin are analyzed.
Methods of magnetic resonance together with optical readout of single defect
centers have been applied in order to observe the coherent dynamics of the
electron and nuclear spins. Long coherence times, in the order of microseconds
for electron spins and tens of microseconds for nuclear spins, recommend the
studied system as a good experimental approach for implementing a 2-qubit gate.",0409067v1
2004-11-18,Entanglement Assisted Metrology,"We propose a new approach to the measurement of a single spin state, based on
nuclear magnetic resonance (NMR) techniques and inspired by the coherent
control over many-body systems envisaged by Quantum Information Processing
(QIP). A single target spin is coupled via the natural magnetic dipolar
interaction to a large ensemble of spins. Applying external radio frequency
(rf) pulses, we can control the evolution of the system so that the spin
ensemble reaches one of two orthogonal states whose collective properties
differ depending on the state of the target spin and are easily measured. We
first describe this measurement process using QIP gates; then we show how
equivalent schemes can be defined in terms of the Hamiltonian of the spin
system and thus implemented under conditions of real control, using well
established NMR techniques. We demonstrate this method with a proof of
principle experiment in ensemble liquid state NMR and simulations for small
spin systems.",0411128v1
2007-07-09,Coherence of an optically illuminated single nuclear spin qubit,"We investigate the coherence properties of individual nuclear spin quantum
bits in diamond [Dutt et al., Science, 316, 1312 (2007)] when a proximal
electronic spin associated with a nitrogen-vacancy (NV) center is being
interrogated by optical radiation. The resulting nuclear spin dynamics are
governed by time-dependent hyperfine interaction associated with rapid
electronic transitions, which can be described by a spin-fluctuator model. We
show that due to a process analogous to motional averaging in nuclear magnetic
resonance, the nuclear spin coherence can be preserved after a large number of
optical excitation cycles. Our theoretical analysis is in good agreement with
experimental results. It indicates a novel approach that could potentially
isolate the nuclear spin system completely from the electronic environment.",0707.1341v2
2007-10-11,Electrically Tunable Spin Polarization in a Carbon-Nanotube Spin Diode,"We have studied the current through a carbon nanotube quantum dot with one
ferromagnetic and one normal-metal lead. For the values of gate voltage at
which the normal lead is resonant with the single available non-degenerate
energy level on the dot, we observe a pronounced decrease in the current for
one bias direction. We show that this rectification is spin-dependent, and that
it stems from the interplay between the spin accumulation and the Coulomb
blockade on the quantum dot. Our results imply that the current is
spin-polarized for one direction of the bias, and that the degree of spin
polarization is fully and precisely tunable using the gate and bias voltages.
As the operation of this spin diode does not require high magnetic fields or
optics, it could be used as a building block for electrically controlled
spintronic devices.",0710.2297v1
2008-11-25,Spin-orbital frustrations and anomalous metallic state in iron-pnictide superconductors,"We develop an understanding of the anomalous metal state of the parent
compounds of recently discovered iron based superconductors starting from a
strong coupling viewpoint, including orbital degrees of freedom. On the basis
of an intermediate-spin (S=1) state for the Fe^{2+} ions, we derive a
Kugel-Khomskii spin-orbital Hamiltonian for the active t_{2g} orbitals. It
turns out to be a highly complex model with frustrated spin and orbital
interactions. We compute its classical phase diagrams and provide an
understanding for the stability of the various phases by investigating its
spin-only and orbital-only limits. The experimentally observed spin-stripe
state is found to be stable over a wide regime of physical parameters and can
be accompanied by three different types of orbital orders. Of these the
orbital-ferro and orbital-stripe orders are particularly interesting since they
break the in-plane lattice symmetry -- a robust feature of the undoped
compounds. We compute the magnetic excitation spectra for the effective spin
Hamiltonian, observing a strong reduction of the ordered moment, and point out
that the proposed orbital ordering pattern can be measured in resonant X-ray
diffraction.",0811.4104v1
2009-01-05,Coherence and control of quantum registers based on electronic spin in a nuclear spin bath,"We consider a protocol for the control of few-qubit registers comprising one
electronic spin embedded in a nuclear spin bath. We show how to isolate a few
proximal nuclear spins from the rest of the environment and use them as
building blocks for a potentially scalable quantum information processor. We
describe how coherent control techniques based on magnetic resonance methods
can be adapted to these electronic-nuclear solid state spin systems, to provide
not only efficient, high fidelity manipulation of the registers, but also
decoupling from the spin bath. As an example, we analyze feasible performances
and practical limitations in a realistic setting associated with
nitrogen-vacancy centers in diamond.",0901.0444v1
2009-01-14,Ab-initio calculations of spin tunneling through an indirect barrier,"We use a fully relativistic layer Green's functions approach to investigate
spin-dependent tunneling through a symmetric indirect band gap barrier like
GaAs/AlAs/GaAs heterostructure along [100] direction. The method is based on
Linear Muffin Tin Orbitals and it is within the Density Functional Theory (DFT)
in the Local Density Approximation (LDA). We find that the results of our {\it
ab-initio} calculations are in good agreement with the predictions of our
previous empirical tight binding model [Phys. Rev. {\bf B}, 075313 (2006)]. In
addition we show the $k_{||}$-dependence of the spin polarization which we did
not previously include in the model. The {\it ab-initio} calculations indicate
a strong $k_{||}$-dependence of the transmission and the spin polarization due
to band non-parabolicity. A large window of 25-50 % spin polarization was found
for a barrier of 8 AlAs monolayers at $k_{||}$ = 0.03 $2\pi/a$. Our
calculations show clearly that the appearance of energy windows with
significant spin polarization depends mostly on the location of transmission
resonances and their corresponding zeros and not on the magnitude of the spin
splitting in the barrier.",0901.2021v1
2009-02-19,Kondo screening suppression by spin-orbit interaction in quantum dots,"We study the transport properties of a quantum dot embedded in an
Aharonov-Bohm ring in the presence of spin-orbit interactions. Using a
numerical renormalization group analysis of the system in the Kondo regime, we
find that the competition of Aharonov-Bohm and spin-orbit dynamical phases
induces a strong suppression of the Kondo state singlet, somewhat akin to an
effective intrinsic magnetic field in the system. This effective field breaks
the spin degeneracy of the localized state and produces a finite magnetic
moment in the dot. By introducing an {\em in-plane} Zeeman field we show that
the Kondo resonance can be fully restored, reestablishing the spin singlet and
a desired spin filtering behavior in the Kondo regime, which may result in full
spin polarization of the current through the ring.",0902.3310v1
2009-03-11,Nanomechanical Detection of Itinerant Electron Spin Flip,"Spin is an intrinsically quantum property, characterized by angular momentum.
A change in the spin state is equivalent to a change in the angular momentum or
mechanical torque. This spin-induced torque has been invoked as the intrinsic
mechanism in experiments ranging from the measurements of angular momentum of
photons g-factor of metals and magnetic resonance to the magnetization reversal
in magnetic multi-layers A spin-polarized current introduced into a nonmagnetic
nanowire produces a torque associated with the itinerant electron spin flip.
Here, we report direct measurement of this mechanical torque and itinerant
electron spin polarization in an integrated nanoscale torsion oscillator, which
could yield new information on the itinerancy of the d-band electrons. The
unprecedented torque sensitivity of 10^{-22} N m/ \sqrt{Hz} may enable
applications for spintronics, precision measurements of CP-violating forces,
untwisting of DNA and torque generating molecules.",0903.1894v1
2009-04-08,Architecture for high-sensitivity single-shot readout and control of the electron spin of individual donors in silicon,"We describe a method to control and detect in single-shot the electron spin
state of an individual donor in silicon with greatly enhanced sensitivity. A
silicon-based Single-Electron Transistor (SET) allows for spin-dependent
tunneling of the donor electron directly into the SET island during the
read-out phase. Simulations show that the charge transfer signals are typically
\Delta q > 0.2 e - over an order of magnitude larger than achievable with
metallic SETs on the SiO2 surface. A complete spin-based qubit structure is
obtained by adding a local Electron Spin Resonance line for coherent spin
control. This architecture is ideally suited to demonstrate and study the
coherent properties of donor electron spins, but can be expanded and integrated
with classical control electronics in the context of scale-up.",0904.1271v4
2009-12-25,Faraday Rotation with Single Nuclear Spin Qubit in a High-Finesse Optical Cavity,"When an off-resonant light field is coupled with atomic spins, its
polarization can rotate depending on the direction of the spins via a Faraday
rotation which has been used for monitoring and controlling the atomic spins.
We observed Faraday rotation by an angle of more than 10 degrees for a single
1/2 nuclear spin of 171Yb atom in a high-finesse optical cavity. By employing
the coupling between the single nuclear spin and a photon, we have also
demonstrated that the spin can be projected or weakly measured through the
projection of the transmitted single ancillary photon.",0912.4948v3
2011-04-22,"High spin states of cation vacancies in GaP, GaN, AlN, BN, ZnO and BeO: A first principles study","High spin states of cation vacancies in GaP, GaN, AlN, BN, ZnO and BeO were
analyzed by first principles calculations. The spin-polarized vacancy-induced
level is located in the band gap in GaP, ZnO and BeO. In the nitrides, the
stronger exchange coupling forces the vacancy states to be resonant with
valence bands, forbids formation of positively charged vacancies in GaN and BN,
and allows Al vacancy in p-AlN to assume the highest possible S=2 spin state.
The shape of the spin density, isotropic in the zinc blende structure, has a
pronounced directional character in the wurtzite structure. Stability of spin
polarization of the vacancy states is determined by spin polarization energies
of anions, as well as by interatomic distances between the vacancy neighbors,
and thus is given by both the lattice constant of the host and the atomic
relaxations around the vacancy. Implications for experiment are discussed.",1104.4420v1
2012-03-05,Coherent multi-flavour spin dynamics in a fermionic quantum gas,"Microscopic spin interaction processes are fundamental for global static and
dynamical magnetic properties of many-body systems. Quantum gases as pure and
well isolated systems offer intriguing possibilities to study basic magnetic
processes including non-equilibrium dynamics. Here, we report on the
realization of a well-controlled fermionic spinor gas in an optical lattice
with tunable effective spin ranging from 1/2 to 9/2. We observe long-lived
intrinsic spin oscillations and investigate the transition from two-body to
many-body dynamics. The latter results in a spin-interaction driven melting of
a band insulator. Via an external magnetic field we control the system's
dimensionality and tune the spin oscillations in and out of resonance. Our
results open new routes to study quantum magnetism of fermionic particles
beyond conventional spin 1/2 systems.",1203.0948v1
2012-04-02,"Spin dynamics of S-state ions in the filled skutterudites La1-xRx$Pt4Ge12 (R= Gd, Eu)","A detailed study of the spin dynamics of the S-state ions Gd3+ and Eu2+ in
the filled skutterudites La1-xRxPt4Ge12 (R= Gd, Eu) is reported. The spin
dynamics is investigated directly by means of Gd3+ and Eu2+ electron spin
resonance (ESR), performed at X-band (~ 9.4 GHz) and Q-band (~ 34 GHz)
frequencies in the temperature intervals 8<T<300 K and 1.5<T<300 K
respectively. The ESR parameters provide direct evidence for the vibrational
behavior of the Gd3+ ions but not for the Eu2+ ions. These results are
interpreted in the light of recent discussions about the spin relaxation in
cage systems. In particular, the Gd3+ spin relaxation in La0.9Gd0.1Pt4Ge12
provide evidence for the existence of an extra phonon mode with an Einstein
temperature (thetaE) ~ 24 K in this system. The work suggests that the
so-called ""rattling"" modes have a general and important role that should be
taken into account in the study of spin dynamics in cage systems.",1204.0481v1
2012-04-13,High resolution spectroscopy of single NV defects coupled with nearby $^{13}$C nuclear spins in diamond,"We report a systematic study of the hyperfine interaction between the
electron spin of a single nitrogen-vacancy (NV) defect in diamond and nearby
$^{13}$C nuclear spins, by using pulsed electron spin resonance spectroscopy.
We isolate a set of discrete values of the hyperfine coupling strength ranging
from 14 MHz to 400 kHz and corresponding to $^{13}$C nuclear spins placed at
different lattice sites of the diamond matrix. For each lattice site, the
hyperfine interaction is further investigated through nuclear spin polarization
measurements and by studying the magnetic field dependence of the hyperfine
splitting. This work provides informations that are relevant for the
development of nuclear-spin based quantum register in diamond.",1204.2947v1
2012-05-25,Study of two-spin entanglement in singlet states,"We study the entanglement properties of two-spin subsystems in spin-singlet
states. The average entanglement between two spins is maximized in a single
valence-bond (VB) state. On the other hand, $E_v^2$ (the average entanglement
between a subsystem of two spins and the rest of the system) can be maximized
through a homogenized superposition of the VB states. The maximal $E_v^2$
rapidly increases with system size and saturates at its maximum allowed value.
We adopt two ways of obtaining maximal $E_v^2$ states: (1) imposing homogeneity
on singlet states; and (2) generating isotropy in a general homogeneous state.
By using these two approaches, we construct explicitly four-spin and six-spin
highly entangled states that are both isotropic and homogeneous. Our maximal
$E^2_v$ states represent a new class of resonating-valence-bond states which we
show to be the ground states of the infinite-range Heisenberg model.",1205.5667v3
2012-08-30,Generation of spin-polarized current using multi-terminated quantum dot with spin-orbit interaction,"We theoretically examine generation of spin-polarized current using
multi-terminated quantum dot with spin-orbit interaction. First, a two-level
quantum dot is analyzed as a minimal model, which is connected to $N$ ($\ge 2$)
external leads via tunnel barriers. When an unpolarized current is injected to
the quantum dot from a lead, a polarized current is ejected to others,
similarly to the spin Hall effect. In the absence of magnetic field, the
generation of spin-polarized current requires $N \ge 3$. The polarization is
markedly enhanced by resonant tunneling when the level spacing in the quantum
dot is smaller than the level broadening due to the tunnel coupling to the
leads. In a weak magnetic field, the orbital magnetization creates a
spin-polarized current even in the two-terminal geometry (N=2). The numerical
study for generalized situations confirms our analytical result using the
two-level model.",1208.6084v1
2013-01-14,Spin coherent states in NMR quadrupolar system: experimental and theoretical applications,"Working with nuclear magnetic resonance (NMR) in quadrupolar spin systems, in
this paper we transfer the concept of atomic coherent state to the nuclear spin
context, where it is referred to as pseudo-nuclear spin coherent state
(pseudo-NSCS). Experimentally, we discuss the initialization of the
pseudo-NSCSs and also their quantum control, implemented by polar and azimuthal
rotations. Theoretically, we compute the geometric phases acquired by an
initial pseudo-NSCS on undergoing three distinct cyclic evolutions: $ i) $ the
free evolution of the NMR quadrupolar system and, by analogy with the evolution
of the NMR quadrupolar system, that of $ii)$ single-mode and $ iii)$ two-mode
Bose-Einstein Condensate like system. By means of these analogies, we derive,
through spin angular momentum operators, results equivalent to those presented
in the literature for orbital angular momentum operators. The pseudo-NSCS
description is a starting point to introduce the spin squeezed state and
quantum metrology into nuclear spin systems of liquid crystal or solid matter.",1301.2862v1
2013-05-03,Dependence of spin pumping spin Hall effect measurements on layer thicknesses and stacking order,"Voltages generated from inverse spin Hall and anisotropic magneto-resistance
effects via spin pumping in ferromagnetic (F)/non-magnetic (N) bilayers are
investigated by means of a broadband ferromagnetic resonance approach. Varying
the non-magnetic layer thickness enables the determination of the spin
diffusion length in Pd of 5.5 +/- 0.5 nm. We also observe a systematic change
of the voltage lineshape when reversing the stacking order of the F/N bilayer,
which is qualitatively consistent with expectations from spin Hall effects.
However, even after independent calibration of the precession angle, systematic
quantitative discrepancies in analyzing the data with spin Hall effects remain.",1305.0745v2
2013-05-31,Enhanced hyperfine-induced spin dephasing in a magnetic-field gradient,"Magnetic-field gradients are important for single-site addressability and
electric-dipole spin resonance of spin qubits in semiconductor devices. We show
that these advantages are offset by a potential reduction in coherence time due
to the non-uniformity of the magnetic field experienced by a nuclear-spin bath
interacting with the spin qubit. We theoretically study spins confined to
quantum dots or at single donor impurities, considering both free-induction and
spin-echo decay. For quantum dots in GaAs, we find that, in a realistic
setting, a magnetic-field gradient can reduce the Hahn-echo coherence time by
almost an order of magnitude. This problem can, however, be resolved by
applying a moderate external magnetic field to enter a motional averaging
regime. For quantum dots in silicon, we predict a cross-over from non-Markovian
to Markovian behavior that is unique to these devices. Finally, for very small
systems such as single phosphorus donors in silicon, we predict a breakdown of
the common Gaussian approximation due to finite-size effects.",1305.7506v2
2013-07-06,Probing the Spin Pumping Mechanism: Exchange Coupling with Exponential Decay in Y3Fe5O12/barrier/Pt Heterostructures,"Ferromagnetic resonance driven spin pumping of pure spin currents from a
ferromagnet into a nonmagnetic material promises new spin-functional devices
with low energy consumption. The mechanism of spin pumping is under intense
investigation and it is widely believed that exchange interaction between the
ferromagnet and nonmagnetic material is responsible for this phenomenon. We
observe a thousand-fold exponential decay of the spin pumping from 20-nm thick
Y3Fe5O12 films to platinum across insulating barriers, from which the
exponential decay lengths of 0.16 and 0.23 nm are extracted for oxide barriers
with band gaps of 4.93 eV and 2.36 eV, respectively. This prototypical
signature of quantum tunneling through a barrier underscores the importance of
exchange coupling for spin pumping and reveals its dependence on the
characteristics of the barrier material.",1307.1816v2
2013-10-13,Optically-driven nuclear-spin-selective Rabi oscillations of single electron spins in diamond,"Optically-driven Rabi oscillations of single electron spins in a diamond
nitrogen vacancy center are realized with two Raman-resonant optical pulses
that are detuned from the respective dipole optical transitions. The Rabi
oscillations are nuclear-spin selective and are robust against rapid
decoherence of the underlying optical transitions, opening the door to
generating phonon-mediated spin entanglement in an optically-driven spin-phonon
system. A direct comparison between the Rabi oscillations and simulated Raman
adiabatic passage along with a detailed theoretical analysis provide a wealth
of information on the coherent spin dynamics and in particular reveal that
decoherence and environmental fluctuations associated with the optical
transitions affect the fidelity of the Rabi oscillations through relatively
large jumps in the transition frequencies.",1310.3525v1
2013-10-24,Dynamics in spinor condensates controlled by a microwave dressing field,"We experimentally study spin dynamics in a sodium antiferromagnetic spinor
condensate with off-resonant microwave pulses. In contrast to a magnetic field,
a microwave dressing field enables us to explore rich spin dynamics under the
influence of a negative net quadratic Zeeman shift $q_{\rm net}$. We find an
experimental signature to determine the sign of $q_{\rm net}$, and observe
harmonic spin population oscillations at every $q_{\rm net}$ except near each
separatrix in phase space where spin oscillation period diverges. In the
negative and positive $q_{\rm net}$ regions, we also observe a remarkably
different relationship between each separatrix and the magnetization. Our data
confirms an important prediction derived from the mean-field theory:
spin-mixing dynamics in spin-1 condensates substantially depends on the sign of
the ratio of $q_{\rm net}$ and the spin-dependent interaction energy. This work
may thus be the first to use only one atomic species to reveal mean-field spin
dynamics, especially the separatrix, which are predicted to appear differently
in spin-1 antiferromagnetic and ferromagnetic spinor condensates.",1310.6785v1
2013-11-26,Electrically and mechanically tunable electron spins in silicon carbide color centers,"The electron spins of semiconductor defects can have complex interactions
with their host, particularly in polar materials like SiC where electrical and
mechanical variables are intertwined. By combining pulsed spin resonance with
ab-initio simulations, we show that spin-spin interactions within SiC neutral
divacancies give rise to spin states with an enhanced Stark effect, sub-10**-6
strain sensitivity, and highly spin-dependent photoluminescence with intensity
contrasts of 15-36%. These results establish SiC color centers as compelling
systems for sensing nanoscale fields.",1311.6832v1
2013-11-28,Dynamic Spin Fluctuations at $T\rightarrow 0$ in a Spin-1/2 Ferromagnetic Kagome Lattice,"We report magnetization, electron spin resonance (ESR), and muon spin
relaxation ($\mu $SR) measurements on single crystals of the $S=1/2$ (Cu$%
^{+2}$) kagom\'{e} compound Cu(1,3-benzendicarboxylate). The $\mu $SR is
carried to temperatures as low as 45 mK. The spin Hamiltonian parameters are
determined from the analysis of the magnetization and ESR data. We find that
this compound has anisotropic ferromagnetic interactions. Nevertheless, no spin
freezing is observed even at temperatures two orders of magnitude lower than
the coupling constants. In light of this finding, the relation between
persistent spin dynamics and spin liquid are reexamined.",1311.7411v1
2013-12-10,Optical signatures of silicon-vacancy spins in diamond,"Colour centres in diamond have emerged as versatile tools for solid-state
quantum technologies ranging from quantum information to metrology, where the
nitrogen-vacancy centre is the most studied to-date. Recently, this toolbox has
expanded to include different materials for their nanofabrication
opportunities, and novel colour centres to realize more efficient spin-photon
quantum interfaces. Of these, the silicon-vacancy centre stands out with
ultrabright single photon emission predominantly into the desirable zero-phonon
line. The challenge for utilizing this centre is to realise the hitherto
elusive optical access to its electronic spin. Here, we report spin-tagged
resonance fluorescence from the negatively charged silicon-vacancy centre. In
low-strain bulk diamond spin-selective excitation under finite magnetic field
reveals a spin-state purity approaching unity in the excited state. We also
investigate the effect of strain on the centres in nanodiamonds and discuss how
spin selectivity in the excited state remains accessible in this regime.",1312.2997v1
2013-12-17,High-fidelity adiabatic inversion of a $^{31}\mathrm{P}$ electron spin qubit in natural silicon,"The main limitation to the high-fidelity quantum control of spins in
semiconductors is the presence of strongly fluctuating fields arising from the
nuclear spin bath of the host material. We demonstrate here a substantial
improvement in single-qubit gate fidelities for an electron spin qubit bound to
a $^{31}$P atom in natural silicon, by applying adiabatic inversion instead of
narrow-band pulses. We achieve an inversion fidelity of 97%, and we observe
signatures in the spin resonance spectra and the spin coherence time that are
consistent with the presence of an additional exchange-coupled donor. This work
highlights the effectiveness of adiabatic inversion techniques for spin control
in fluctuating environments.",1312.4647v1
2013-12-17,Low energy magnetic excitations in the spin-orbital Mott insulator Sr$_2$IrO$_4$,"We report a high-field electron spin resonance study in the sub-THz frequency
domain of a single crystal of Sr$_2$IrO$_4$ that has been recently proposed as
a prototypical spin-orbital Mott insulator. In the antiferromagnetically (AFM)
ordered state with noncollinear spin structure that occurs in this material at
$T_{\rm N} \approx 240$ K we observe both the ""low"" frequency mode due to the
precession of weak ferromagnetic moments arising from a spin canting, and the
""high"" frequency modes due to the precession of the AFM sublattices.
Surprisingly, the energy gap for the AFM excitations appears to be very small,
amounting to 0.83 meV only. This suggests a rather isotropic Heisenberg
dynamics of interacting Ir$^{4+}$ effective spins despite the spin-orbital
entanglement in the ground state.",1312.4847v2
2013-12-30,Indirect control of spin precession by electric field via spin-orbit coupling,"The spin-orbit coupling (SOC) can mediate electric-dipole spin resonance
(EDSR) in an a.c. electric field. In this letter, the EDSR is essentially
understood as an spin precession under an effective a.c. magnetic field induced
by the SOC in the reference frame, which is exactly following the classical
trajectory of the electron and obtained by applying a quantum linear coordinate
transformation. With this observation for one-dimensional (1D) case, we find a
upper limit for the spin-flipping speed in the EDSR-based control of spin,
which is given by the accessible data from the current experiment. For
two-dimensional case, the azimuthal dependence of the effective magnetic field
can be used to measure the ratio of the Rashba and Dresselhause SOC strengths.",1312.7635v3
2014-01-06,The empirical Monod-Beuneu relation of spin-relaxation revisited for elemental metals,"Monod and Beuneu [Monod and Beuneu, Phys. Rev. B 19, 911 (1979)] established
the validity of the Elliott-Yafet theory for elemental metals through
correlating the experimental electron spin resonance line-width with the
so-called spin-orbit admixture coefficients and the momentum-relaxation theory.
The spin-orbit admixture coefficients data were based on atomic spin-orbit
splitting. We highlight two shortcomings of the previous description: i) the
momentum-relaxation involves the Debye temperature and the electron-phonon
coupling whose variation among the elemental metals was neglected, ii) the
Elliott-Yafet theory involves matrix elements of the spin-orbit coupling (SOC),
which are however not identical to the SOC induced energy splitting of the
atomic levels, even though the two have similar magnitudes. We obtain the
empirical spin-orbit admixture parameters for the alkali metals by considering
the proper description of the momentum relaxation theory. In addition, we
present a model calculation which highlights the difference between the SOC
matrix element and energy splitting.",1401.1048v1
2014-03-11,Spin squeezing in an ensemble of quadrupolar nuclei NMR system,"We have characterized spin-squeezed states produced at a temperature of
$26^\circ{\mathrm C}$ on a Nuclear Magnetic Resonance (NMR) quadrupolar system.
The implementation is carried out in an ensemble of $^{133}$Cs nuclei with spin
$I=7/2$ of a lyotropic liquid crystal sample. We identify the source of spin
squeezing due to the interaction between the quadrupole moment of the nuclei
and the electric field gradients internally present in the molecules. We use
the spin angular momentum representation to describe formally the nonlinear
operators that produce the spin squeezing. The quantitative and qualitatively
characterization of the spin squeezing phenomena is performed through a
squeezing parameter and squeezing angle developed for the two-mode BEC system,
and, as well, by the Wigner quasi-probability distribution function. The
generality of the present experimental scheme indicates its potential
applications on solid state physics.",1403.2706v1
2014-08-11,Hole spin dynamics and hole $g$ factor anisotropy in coupled quantum well systems,"Due to its p-like character, the valence band in GaAs-based heterostructures
offers rich and complex spin-dependent phenomena. One manifestation is the
large anisotropy of Zeeman spin splitting. Using undoped, coupled quantum wells
(QWs), we examine this anisotropy by comparing the hole spin dynamics for high-
and low-symmetry crystallographic orientations of the QWs. We directly measure
the hole $g$ factor via time-resolved Kerr rotation, and for the low-symmetry
crystallographic orientations (110) and (113a), we observe a large in-plane
anisotropy of the hole $g$ factor, in good agreement with our theoretical
calculations. Using resonant spin amplification, we also observe an anisotropy
of the hole spin dephasing in the (110)-grown structure, indicating that
crystal symmetry may be used to control hole spin dynamics.",1408.2360v1
2014-09-02,Quantum spin coherence in halogen-modified Cr$_7$Ni molecular nanomagnets,"Among the factors determining the quantum coherence of the spin in molecular
magnets is the presence and the nature of nuclear spins in the molecule. We
have explored modifying the nuclear spin environment in Cr$_7$Ni-based
molecular nanomagnets by replacing hydrogen atoms with deuterium or the halogen
atoms, fluorine or chlorine. We find that the spin coherence, studied at low
temperatures by pulsed electron spin resonance, is modified by a range of
factors, including nuclear spin and magnetic moment, changes in dynamics owing
to nuclear mass, and molecular morphology changes.",1409.0821v2
2014-09-16,Phonon-modulated magnetic interactions and spin Tomonaga-Luttinger liquid in the p-orbital antiferromagnet CsO2,"The magnetic response of antiferromagnetic CsO2, coming from the p-orbital
S=1/2 spins of anionic O2- molecules, is followed by 133Cs nuclear magnetic
resonance across the structural phase transition occuring at Ts1=61 K on
cooling. Above Ts1, where spins form a square magnetic lattice, we observe a
huge, nonmonotonic temperature dependence of the exchange coupling originating
from thermal librations of O2- molecules. Below Ts1, where antiferromagnetic
spin chains are formed as a result of p-orbital ordering, we observe a spin
Tomonaga-Luttinger-liquid behavior of spin dynamics. These two interesting
phenomena, which provide rare simple manifestations of the coupling between
spin, lattice and orbital degrees of freedom, establish CsO2 as a model system
for molecular solids.",1409.4818v2
2014-09-22,Donor Spin Qubits in Ge-based Phononic Crystals,"We propose qubits based on shallow donor electron spins in germanium.
Spin-orbit interaction for donor spins in germanium is in many orders of
magnitude stronger than in silicon. In a uniform bulk material it leads to very
short spin lifetimes. However the lifetime increases dramatically when the
donor is placed into a quasi-2D phononic crystal and the energy of the Zeeman
splitting is tuned to lie within a phonon bandgap. In this situation single
phonon processes are suppressed by energy conservation. The remaining
two-phonon decay channel is very slow. The Zeeman splitting within the gap can
be fine tuned to induce a strong, long-range coupling between the spins of
remote donors via exchange by virtual phonons. This, in turn, opens a very
efficient way to manipulate the quits. We explore various geometries of
phononic crystals in order to maximize the coherent qubit-qubit coupling while
keeping the decay rate minimal. We find that phononic crystals with unit cell
sizes of 100-150 nm are viable candidates for quantum computing applications
and suggest several spin-resonance experiments to verify our theoretical
predictions.",1409.6285v1
2014-11-28,Position-dependent spin-orbit coupling for ultracold atoms,"We theoretically explore atomic Bose-Einstein condensates (BECs) subject to
position-dependent spin-orbit coupling (SOC). This SOC can be produced by
cyclically laser coupling four internal atomic ground (or metastable) states in
an environment where the detuning from resonance depends on position. The
resulting spin-orbit coupled BEC phase-separates into domains, each of which
contain density modulations - stripes - aligned either along the x or y
direction. In each domain, the stripe orientation is determined by the sign of
the local detuning. When these stripes have mismatched spatial periods along
domain boundaries, non-trivial topological spin textures form at the interface,
including skyrmions-like spin vortices and anti-vortices. In contrast to
vortices present in conventional rotating BECs, these spin-vortices are stable
topological defects that are not present in the corresponding homogenous
stripe-phase spin-orbit coupled BECs.",1411.7813v2
2015-01-19,Effect of Exchange Interaction on Magnetic Thermal Fluctuation and Spin Susceptibility,"The expression of the thermal fluctuation parameter in the stochastic
Landau-Lifshitz-Gilbert equation has been derived from a fundamental quantum
theory of spins and phonons, in which the exchange interaction between nearest
atoms has been included. Our studies show that the thermal fluctuation
decreases exponentially with increasing exchange interaction. The non-uniform
fluctuation of local spins make the spin susceptibility much different from the
result derived by the macro-spin model or single spin model. The related spin
susceptibility depends not only on the strength of exchange interaction, but
also on the lattice structure. The non-uniform fluctuation can lead to an extra
broadening of the resonance line width along with the broadening arisen from
the Gilbert damping.",1501.04503v2
2015-02-13,Coherent heteronuclear spin dynamics in an ultracold spin-1 mixture,"We report the observation of coherent heteronuclear spin dynamics driven by
inter-species spin-spin interaction in an ultracold spinor mixture, which
manifests as periodical and well correlated spin oscillations between two
atomic species. In particular, we investigate the magnetic field dependence of
the oscillations and find a resonance behavior which depends on {\em both} the
linear and quadratic Zeeman effects and the spin-dependent interaction. We also
demonstrate a unique knob for controlling the spin dynamics in the spinor
mixture with species-dependent vector light shifts. Our finds are in agreement
with theoretical simulations without any fitting parameters.",1502.03867v1
2015-02-13,Antiferromagnet-Mediated Spin Transfer Between Metal and Ferromagnet,"We develop a theory for spin transported by coherent Neel dynamics through an
antiferromagnetic insulator coupled to a ferromagnetic insulator on one side
and a current-carrying normal metal with strong spin-orbit coupling on the
other. The ferromagnet is considered within the mono-domain limit and we assume
its coupling to the local antiferromagnet Neel order at the
ferromagnet|antiferromagnet interface through exchange coupling. Coupling
between the charge current and the local Neel order at the other interface is
described using spin Hall phenomenology. Spin transport through the
antiferromagnet, assumed to possess an easy-axis magnetic anisotropy, is solved
within the adiabatic approximation and the effect of spin current flowing into
the ferromagnet on its resonance linewidth is evaluated. Onsager reciprocity is
used to evaluate the inverse spin Hall voltage generated across the metal by a
dynamic ferromagnet as a function the antiferromagnet thickness.",1502.04128v1
2015-04-03,Single-shot measurement of transient nuclear magnetization with spin-noise spectroscopy in n-GaAs microcavities,"We exploit spin noise spectroscopy (SNS) to directly observe build-up of
dynamic nuclear polarization and relaxation of a perturbed nuclear spin-system
to its equilibrium state in a single-shot experiment. The SNS experiments were
performed on a layer of bulk $n$-type GaAs embedded into a high-finesse
microcavity with negative detuning. The dynamic nuclear spin polarization is
observed as a shift of the peak in the electron spin noise spectrum due to the
build-up of the Overhauser field acting on the electron spin. The relaxation
dynamics of nuclear spin system was revealed in the time-resolved SNS
experiments where the exponential decay of the Overhauser field with
characteristic timescale of hundreds of seconds was detected. We show that
elliptically polarized laser beam tuned in resonance with the cavity mode,
whose energy corresponds to nominal transparency of the semiconductor, can
nevertheless produce a sizable nuclear polarization.",1504.00799v1
2015-05-15,Direct detection of pure spin-current by x-ray pump-probe measurements,"By synchronizing a microwave waveform with the synchrotron x-ray pulses, we
use the ferromagnetic resonance (FMR) of the Py (Ni81Fe19) layer in a
Py/Cu/Cu75Mn25/Cu/Co multilayer to pump a pure spin current into the Cu75Mn25
spacer layer, and then directly probe the spin current in the Cu75Mn25 layer by
a time-resolved x-ray magnetic circular dichroism (XMCD). This element-specific
pump-probe measurement unambiguously identifies the AC spin current in the
Cu75Mn25 layer. In addition, phase resolved x-ray measurements reveal a
characteristic bipolar phase behavior of the Co spins that is a fingerprint of
spin-current driven spin precession.",1505.03959v2
2015-07-06,Nuclear spin noise in NMR revisited,"The theoretical shapes of nuclear spin-noise spectra in NMR are derived by
considering a receiver circuit with finite, preamplifier input impedance and a
transmission line between the preamplifier and the probe. Using this model, it
becomes possible to reproduce all observed experimental features: variation of
the NMR resonance linewidth as a function of the transmission line phase,
nuclear spin-noise signals appearing as a ""bump"" or as a ""dip"" superimposed on
the average electronic noise level even for a spin system and probe at the same
temperature, pure in-phase Lorentzian spin-noise signals exhibiting
non-vanishing frequency shifts. Extensive comparison to experimental
measurements validate the model predictions, and define the conditions for
obtaining pure in-phase Lorentzian-shape nuclear spin noise with a vanishing
frequency shift, in other words, the conditions for simultaneously obtaining
the Spin-Noise and Frequency-Shift Tuning Optima.",1507.01398v2
2015-08-11,Suppression of the impurity-induced local magnetism by the opening of a spin pseudogap in Ni-doped Sr$_2$CuO$_3$,"The $S=1/2$ antiferromagnetic Heisenberg spin chain compound Sr$_2$CuO$_3$
doped with $1 \%$ and $2 \%$ of Ni impurities has been studied by means of
$^{63}$Cu nuclear magnetic resonance. A strong decrease of the spin-lattice
relaxation rate $T_1^{-1}$ at low temperatures points toward a spin gap, while
a stretching exponent $\lambda < 1$ and a frequency dependence of $T_1^{-1}$
indicate that this spin gap varies spatially and should rather be characterized
as a spin pseudogap. The magnitude of the spin pseudogap scales with doping
level. Our results therefore evidence the finite-size character of this
phenomenon. Moreover, an unusual narrowing of the low temperature NMR lines
reveals the suppression of the impurity-induced staggered paramagnetic response
with increasing doping level.",1508.02529v1
2015-08-26,Multistability and spin diffusion enhanced lifetimes in dynamic nuclear polarization in a double quantum dot,"The control of nuclear spins in quantum dots is essential to explore their
many-body dynamics and exploit their prospects for quantum information
processing. We present a unique combination of dynamic nuclear spin
polarization and electric-dipole-induced spin resonance in an electrostatically
defined double quantum dot (DQD) exposed to the strongly inhomogeneous field of
two on-chip nanomagnets. Our experiments provide direct and unrivaled access to
the nuclear spin polarization distribution and allow us to establish and
characterize multiple fixed points. Further, we demonstrate polarization of the
DQD environment by nuclear spin diffusion which significantly stabilizes the
nuclear spins inside the DQD.",1508.06522v2
2015-09-03,Long-lived states with well-defined spins in spin-$1/2$ homogeneous Bose gases,"Many-body eigenfunctions of the total spin operator can be constructed from
the spin and spatial wavefunctions with non-trivial permutation symmetries.
Spin-dependent interactions can lead to relaxation of the spin eigenstates to
the thermal equilibrium. A mechanism that stabilizes the many-body entangled
states is proposed here. Surprisingly, in spite coupling with the chaotic
motion of the spatial degrees of freedom, the spin relaxation can be suppressed
by destructive quantum interference due to spherical vector and tensor terms of
the spin-dependent interactions. Tuning the scattering lengths by the method of
Feshbach resonances, readily available in cold atomic labs, can enhance the
relaxation timescales by several orders of magnitude.",1509.01264v3
2016-01-20,Enhanced photonic spin Hall effect with subwavelength topological edge states,"Photonic structures offer unique opportunities for controlling light-matter
interaction, including the photonic spin Hall effect associated with the
transverse spin-dependent displacement of light that propagates in specially
designed optical media. However, due to small spin-orbit coupling, the photonic
spin Hall effect is usually weak at the nanoscale. Here we suggest
theoretically and demonstrate experimentally, in both optics and microwave
experiments, the photonic spin Hall effect enhanced by topologically protected
edge states in subwavelength arrays of resonant dielectric particles. Based on
direct near-field measurements, we observe the selective excitation of the
topological edge states controlled by the handedness of the incident light.
Additionally, we reveal the main requirements to the symmetry of photonic
structures to achieve a topology-enhanced spin Hall effect, and also analyse
the robustness of the photonic edge states against the long-ranged coupling.",1601.05264v1
2016-04-10,Measurement of spin coherence using Raman scattering,"Ramsey interferometry provides a natural way to determine the coherence time
of most qubit systems. Recent experiments on quantum dots however, demonstrated
that dynamical nuclear spin polarization can strongly influence the measurement
process, making it difficult to extract the $T_2^*$ coherence time using
optical Ramsey pulses. Here, we demonstrate an alternative method for spin
coherence measurement that is based on first-order coherence of photons
generated in spin-flip Raman scattering. We show that if a quantum emitter is
driven by a weak monochromatic laser, Raman coherence is determined exclusively
by spin coherence, allowing for a direct determination of spin $T_2^*$ time.
When combined with coherence measurements on Rayleigh scattered photons, our
technique enables us to identify coherent and incoherent contributions to
resonance fluorescence, and to minimize the latter. We verify the validity of
our technique by comparing our results to those determined from Ramsey
interferometry for electron and heavy-hole spins.",1604.02685v1
2016-04-27,Spin exchange collision mixing of the K and Rb ac Stark shifts,"In a hybrid pumping alkali vapor cell that both K and Rb are filled, K atom
spins are optically pumped by laser and Rb atom spins are polarized by the K
spins through spin exchange. We find that the AC Stark shift of the Rb atoms is
composed of not only the AC Stark shift of the Rb atoms caused by the far off
resonant pumping laser which is tuned to the K absorption lines, but also the
AC Stark shift of the K atom spins. The mixing of the light shifts through fast
spin exchange between K and Rb atoms are studied in this paper and we
demonstrate a K-Rb-21Ne co-magnetometer in which the AC Stark shift of the Rb
atoms are reduced by the collision mixing.",1604.07908v1
2016-05-16,Spin-polarization in the vicinity of quantum point contact with spin-orbit interaction,"We have developed a novel technique for detection of spin polarization with a
quantum dot weakly coupled to the objective device. The disturbance to the
object in this technique is very small since the detection is performed through
sampling of single electrons in the object with very slow rate. We have applied
the method to a quantum point contact (QPC) under a spin-orbit interaction. A
high degree of spin polarization in the vicinity of the QPC was detected when
the conductance stayed on a plateau at a half of the unit conductance quantum
($G_{\rm q}/2\equiv e^2/h$), and also on another plateau at $2e^2/h$. On the
half-quantum plateau, the degree of polarization $P$ decreased with the bias
source-drain voltage of the QPC while $P$ increased on the single-quantum
plateau, manifesting that different mechanisms of polarization were working on
these plateaus. Very long spin relaxation times in the detector quantum dot
probably due to dynamical nuclear spin polarization were observed. Anomalous
decrease of $P$ around zero-bias was observed at a Kondo-like resonance peak.",1605.04685v1
2016-07-26,Spin-orbit signatures in the dynamics of singlet-triplet qubits in double quantum dots,"We characterize numerically and analytically the signatures of the spin-orbit
interaction in a two-electron GaAs double quantum dot in the presence of an
external magnetic field. In particular, we obtain the return probability of the
singlet state by simulating Landau-Zener voltage detuning sweeps which traverse
the singlet-triplet ($S-T_+$) resonance. Our results indicate that
non-spin-conserving interdot tunneling processes arising from the spin-orbit
interaction have well defined signatures. These allow direct access to the
spin-orbit interaction scales and are characterized by a frequency shift and
Fourier amplitude modulation of the Rabi flopping dynamics of the
singlet-triplet qubits $S-T_0$ and $S-T_+$. By applying the Bloch-Feshbach
projection formalism, we demonstrate analytically that the aforementioned
effects originate from the interplay between spin-orbit interaction and
processes driven by the hyperfine interaction between the electron spins and
those of the GaAs nuclei.",1607.07852v3
2016-09-07,Spin excitations in the quasi-two-dimensional charge-ordered insulator $α$-(BEDT-TTF)$_2$I$_3$ probed via $^{13}$C NMR,"The spin excitations from the nonmagnetic charge-ordered insulating state of
$\alpha$-(BEDT-TTF)$_2$I$_3$ at ambient pressure have been investigated by
probing the static and low-frequency dynamic spin susceptibilities via
site-selective nuclear magnetic resonance at $^{13}$C sites. The site-dependent
values of the shift and the spin-lattice relaxation rate $1/T_1$ below the
charge-ordering transition temperature ($T_{CO} \approx$ 135 K) demonstrate a
spin density imbalance in the unit cell, in accord with the charge-density
ratio reported earlier. The shift and $1/T_1$ show activated temperature
dependence with a static (shift) gap $\Delta_S \approx$ 47-52 meV and a dynamic
($1/T_1$) gap $\Delta_R \approx$ 40 meV. The sizes of the gaps are well
described in terms of a localized spin model, where spin one-half
antiferromagnetic dimer chains are weakly coupled with each other.",1609.01906v1
2016-10-07,Spin-orbit coupling controlled $J=3/2$ electronic ground state in 5$d^{3}$ oxides,"Entanglement of spin and orbital degrees of freedom drives the formation of
novel quantum and topological physical states. Discovering new spin-orbit
entangled ground states and emergent phases of matter requires both
experimentally probing the relevant energy scales and applying suitable
theoretical models. Here we report resonant inelastic x-ray scattering
measurements of the transition metal oxides Ca$_3$LiOsO$_6$ and Ba$_2$YOsO$_6$.
We invoke an intermediate coupling approach that incorporates both spin-orbit
coupling and electron-electron interactions on an even footing and reveal the
ground state of $5d^3$ based compounds, which has remained elusive in
previously applied models, is a novel spin-orbit entangled J=3/2 electronic
ground state. This work reveals the hidden diversity of spin-orbit controlled
ground states in 5d systems and introduces a new arena in the search for
spin-orbit controlled phases of matter.",1610.02375v1
2017-07-02,Dynamics of one-dimensional electrons with broken spin-charge separation,"Spin-charge separation is known to be broken in many physically interesting
one-dimensional (1D) and quasi-1D systems with spin-orbit interaction because
of which spin and charge degrees of freedom are mixed in collective
excitations. Mixed spin-charge modes carry an electric charge and therefore can
be investigated by electrical means. We explore this possibility by studying
the dynamic conductance of a 1D electron system with image-potential-induced
spin-orbit interaction. The real part of the admittance reveals an oscillatory
behavior versus frequency that reflects the collective excitation resonances
for both modes at their respective transit frequencies. By analyzing the
frequency dependence of the conductance the mode velocities can be found and
their spin-charge structure can be determined quantitatively.",1707.00316v3
2017-08-14,Spin-resolved electronic structure of ferroelectric α-GeTe and multiferroic Ge1-xMnxTe,"Germanium telluride features special spin-electric effects originating from
spin-orbit coupling and symmetry breaking by the ferroelectric lattice
polarization, which opens up many prospectives for electrically tunable and
switchable spin electronic devices. By Mn doping of the {\alpha}-GeTe host
lattice, the system becomes a multiferroic semiconductor possessing
magnetoelectric properties in which the electric polarization, magnetization
and spin texture are coupled to each other. Employing spin- and angle-resolved
photoemission spectroscopy in bulk- and surface-sensitive energy ranges and by
varying dipole transition matrix elements, we disentangle the bulk, surface and
surface-resonance states of the electronic structure and determine the spin
textures for selected parameters. From our results, we derive a comprehensive
model of the {\alpha}-GeTe surface electronic structure which fits experimental
data and first principle theoretical predictions and we discuss the
unconventional evolution of the Rashba-type spin splitting upon manipulation by
external B- and E-fields.",1708.04104v1
2017-11-17,Measuring anisotropic spin relaxation in graphene,"We compare different methods to measure the anisotropy of the spin-lifetime
in graphene. In addition to out-of-plane rotation of the ferromagnetic
electrodes and oblique spin precession, we present a Hanle experiment where the
electron spins precess around either a magnetic field perpendicular to the
graphene plane or around an in-plane field. In the latter case, electrons are
subject to both in-plane and out-of-plane spin relaxation. To fit the data, we
use a numerical simulation that can calculate precession with anisotropies in
the spin-lifetimes under magnetic fields in any direction. Our data show a
small, but distinct anisotropy that can be explained by the combined action of
isotropic mechanisms, such as relaxation by the contacts and resonant
scattering by magnetic impurities, and an anisotropic Rashba spin-orbit based
mechanism. We also assess potential sources of error in all three types of
experiment and conclude that the in-plane/out-of-plane Hanle method is most
reliable.",1711.06472v2
2017-12-01,Coherent spin dynamics of ytterbium ions in yttrium orthosilicate,"We investigate the electron and nuclear spin coherence properties of
ytterbium ($\mathrm{Yb}^{3+}$) ions with non-zero nuclear spin, within an
yttrium orthosilicate (Y$_2$SiO$_5$) crystal, with a view to their potential
application in quantum memories or repeaters. We find electron spin-lattice
relaxation times are maximised at low magnetic field ($<100$ mT) where
$g~\sim6$, reaching 5 s at 2.5 K, while coherence times are maximised when
addressing ESR transitions at higher fields where $g\sim0.7$ where a Hahn echo
measurement yields $T_2$ up to 73 $\mu$s. Dynamical decoupling (XY16) can be
used to suppress spectral diffusion and extend the coherence lifetime to over
0.5 ms, close to the limit of instantaneous diffusion. Using Davies
electron-nuclear-double-resonance (ENDOR), we performed coherent control of the
$^{173}\mathrm{Yb}^{3+}$ nuclear spin and studied its relaxation dynamics. At
around 4.5 K we measure a nuclear spin $T_1$ and $T_2$ of 4 and 0.35 ms,
respectively, about 4 and 14 times longer than the corresponding times for the
electron spin.",1712.00435v1
2017-12-14,Synthesis of antisymmetric spin exchange interaction and entanglement generation with chiral spin states in a superconducting circuit,"We have synthesized the anti-symmetric spin exchange interaction (ASI), which
is also called the Dzyaloshinskii-Moriya interaction, in a superconducting
circuit containing five superconducting qubits connected to a bus resonator, by
periodically modulating the transition frequencies of the qubits with different
modulation phases. This allows us to show the chiral spin dynamics in three-,
four- and five-spin clusters. We also demonstrate a three-spin chiral logic
gate and entangle up to five qubits in Greenberger-Horne-Zeilinger states. Our
results pave the way for quantum simulation of magnetism with ASI and quantum
computation with chiral spin states.",1712.05261v2
2017-12-25,Coherent states in Magnetic Resonance,"In NMR experiments, interaction of quantized radio-frequency (rf) field leads
to entanglement of nuclear spin with the electromagnetic field. In an entangled
state, the nuclear spins are depolarized with no net magnetization, which
cannot give a detectable signal in inductive detection. We show that when the
electromagnetic field is in coherent state, inductive detection is just true.
We develop the mathematics to study the evolution of a coherent rf-field with a
sample of all polarized spins. We show that evolution can be solved in closed
form as a separable state of rf-field and spin ensemble, where spin ensemble
evolves according to Bloch equations in an rf field. We extend the analysis and
results to a spin ensemble with Boltzmann polarization. The rabi frequency and
coupling strength of spins to rf-field depends on number state of the rf-field.
We show that in interaction with a coherent rf-field, this variation in
coupling strength, introduces negligible error.",1712.09060v1
2018-01-03,Negative spin-Hall angle and anisotropic spin-orbit torques in epitaxial IrMn,"A spin-torque ferromagnetic resonance study is performed in epitaxial
$\mathrm{Fe / Ir_{15}Mn_{85}}$ bilayers with different Fe thicknesses. We
measure a negative spin-Hall angle of a few percent in the antiferromagnetic
IrMn in contrast to previously reported positive values. A large spin-orbit
field with Rashba symmetry opposing the Oersted field is also present.
Magnitudes of measured spin-orbit torques depend on the crystallographic
direction of current and are correlated with the exchange bias direction set
during growth. We suggest that the uncompensated moments at the Fe / IrMn
interface are responsible for the observed anisotropy. Our findings highlight
the importance of crystalline and magnetic structures for the spin-Hall effect
in antiferromagnets.",1801.01065v1
2018-05-14,Electric field control of spins in molecular magnets,"Coherent control of individual molecular spins in nano-devices is a pivotal
prerequisite for fulfilling the potential promised by molecular spintronics. By
applying electric field pulses during time-resolved electron spin resonance
measurements, we measure the sensitivity of the spin in several
antiferromagnetic molecular nanomagnets to external electric fields. We find a
linear electric field dependence of the spin states in Cr$_7$Mn, an
antiferromagnetic ring with a ground-state spin of $S=1$, and in a frustrated
Cu$_3$ triangle, both with coefficients of about $2~\mathrm{rad}\,
\mathrm{s}^{-1} / \mathrm{V} \mathrm{m}^{-1}$. Conversely, the
antiferromagnetic ring Cr$_7$Ni, isomorphic with Cr$_7$Mn but with $S=1/2$,
does not exhibit a detectable effect. We propose that the spin-electric field
coupling may be used for selectively controlling individual molecules embedded
in nanodevices.",1805.05256v2
2018-05-19,Optically driven spin pumping mediating collective magnetization dynamics in a spin valve structure,"We demonstrate spin pumping, i.e. the generation of a pure spin current by
precessing magnetization, without application of microwave radiation commonly
used in spin pumping experiments. We use femtosecond laser pulses to
simultaneously launch the magnetization precession in each of two ferromagnetic
layers of a Galfenol-based spin valve and monitor the temporal evolution of the
magnetizations. The spin currents generated by the precession cause a dynamic
coupling of the two layers. This coupling has dissipative character and is
especially efficient when the precession frequencies in the two layers are in
resonance, where coupled modes with strongly different decay rates are formed.",1805.07669v1
2017-05-10,Interplay of valley polarization and dynamic nuclear polarization in 2D transition metal dichalcogenides,"The interplay of Ising spin-orbit coupling and non-trivial band topology in
transition metal dichalcogenides (TMDs) produces anomalous transport and
optical properties that are very different from a regular 2D electron gas. The
spin-momentum locking of optically excited carriers near a valley point can
give rise to an anomalous spin-valley Hall current under the application of an
in-plane electric field. TMDs also exhibit strong electron-nuclear hyperfine
interactions, but their effect on spin-valley-locked currents remains unknown.
Here, we show that hyperfine interactions can create a feedback mechanism in
which spin-valley currents generate significant dynamical nuclear polarization
which in turn Zeeman shifts excitonic transitions out of resonance with an
optical driving field, saturating the production of spin-valley polarization.
We propose an experimental signature of dynamic nuclear polarization which can
be detected via measurements of the anomalous Hall current. Our results help to
elucidate the interplay of valley polarization and nuclear spin dynamics in
TMDs.",1705.03909v2
2017-05-24,Spin-singlet superconductivity in doped topological crystalline insulator Sn_{0.96}In_{0.04}Te,"The In-doped topological crystalline insulator Sn_{1-x}In_xTe is a candidate
for a topological superconductor, where pseudo-spin-triplet state has been
proposed. To clarify the spin symmetry of Sn_{1-x}In_xTe, we perform
^{125}Te-nuclear magnetic resonance (NMR) measurements in polycrystalline
samples with 0< x <0.15. The penetration depth calculated from the NMR line
width is T-independent below half the superconducting transition temperature
(T_c) in polycrystalline Sn_{0.96}In_{0.04}Te, which indicates a fully-opened
superconducting gap. In this sample, the spin susceptibility measured by the
spin Knight shift (K_s) at an external magnetic field of H_0 = 0.0872 T
decreases below T_c, and K_s(T=0)/K_s(T=T_c) reaches to 0.36 \pm 0.10, which is
far below the limiting value 2/3 expected for a spin-triplet state for a cubic
crystal structure. Our result indicates that polycrystalline
Sn_{0.96}In_{0.04}Te is a spin-singlet superconductor.",1705.08636v2
2017-05-30,Fast optical control of spin in semiconductor interfacial structures,"We report on a picosecond-fast optical removal of spin polarization from a
self-confined photo-carrier system at an undoped GaAs/AlGaAs interface
possessing superior long-range and high-speed spin transport properties. We
employed a modified resonant spin amplification technique with unequal
intensities of subsequent pump pulses to experimentally distinguish the
evolution of spin populations originating from different excitation laser
pulses. We demonstrate that the density of spins, which is injected into the
system by means of the optical orientation, can be controlled by reducing the
electrostatic confinement of the system using an additional generation of
photocarriers. It is also shown that the disturbed confinement recovers within
hundreds of picoseconds after which spins can be again photo-injected into the
system.",1705.10627v1
2018-02-08,Coherent control of solid state nuclear spin nano-ensembles,"Detecting and controlling nuclear spin nano-ensembles is crucial for the
further development of nuclear magnetic resonance (NMR) spectroscopy and for
the emerging solid state quantum technology. Here we present the fabrication of
a $\approx$ 1 nanometre thick diamond layer consisting of $^{13}$C nuclear
spins doped with Nitrogen-Vacancy centres (NV) embedded in a spin-free $^{12}$C
crystal matrix. A single NV in the vicinity of the layer is used for
polarization of the $^{13}$C spins and the readout of their magnetization. We
demonstrate a method for coherent control of few tens of nuclear spins by using
radio frequency pulses and show the basic coherent control experiments - Rabi
oscillations, Ramsey spectroscopy and Hahn echo, though any NMR pulse sequence
can be implemented. The results shown present a first steps towards the
realization of a nuclear spin based quantum simulator.",1802.02921v1
2018-08-01,Neutrino spin and spin-flavour oscillations in transversal matter currents with standard and non-standard interactions,"After a brief history of two known types of neutrino mixing and oscillations,
including neutrino spin and spin-flavour oscillations in the transversal
magnetic field, we perform systematic study of a new phenomenon of neutrino
spin and spin-flavour oscillations engendered by the transversal matter
currents on the bases of the developed quantum treatment of the phenomenon.
Possibilities for the resonance amplification of these new types of
oscillations by the longitudinal matter currents and longitudinal magnetic
fields are analyzed. Neutrino spin-flavour oscillations engendered by the
transversal matter currents in the case of non-standard interactions of
neutrinos with background matter are also considered",1808.00302v2
2018-08-08,Analog Quantum Simulation of Extremely Sub-Ohmic Spin-Boson Models,"We propose a scheme for the quantum simulation of sub-Ohmic spin--boson
models by color centers in free-standing hexagonal boron nitride (h-BN)
membranes. The electronic spin of a color center that couples to the membrane
vibrational spectrum constitute the physical model. The spin-motion coupling is
provided by an external magnetic field gradient. In this study, we show that a
class of spectral densities can be attained by engineering geometry and
boundary conditions of the h-BN resonator. We then put our focus on two extreme
cases, i.e. $1/f$- and white-noise spectral densities. Spin coherence and
polarization dynamics are studied. Our calculations show coherence revivals at
periods set by the bath characteristic frequency signaling the non-Markovian
nature of the baths. The nonequilibrium dynamics of the spin polarization
exhibits a coherent localization, a property peculiar to the quantum phase
transition in extremely sub-Ohmic spin-boson models. Our scheme may find
application in understanding sources of decoherence in solid-state quantum
bits.",1808.02916v1
2019-02-10,Spin asymmetry in single pion production induced by weak interactions of neutrinos with polarized nucleons,"The single pion production (SPP) in the charged-current neutrino
(antineutrino) scattering off the polarized nucleon is discussed. The spin
asymmetry is predicted within two approaches. The spin polarizations of the
target nucleon that are longitudinal and perpendicular to the neutrino momentum
are considered. It is shown, in several examples, that information about the
SPP dynamics coming from the spin asymmetry is complementary to information
obtained from measurements of spin averaged cross section. Indeed, the spin
asymmetry is sensitive to the nonresonance background description of the SPP
model. For the normal polarization of the target, the spin asymmetry is given
by the interference between the resonance and the nonresonance contributions.",1902.03671v2
2020-08-09,Reduction of surface spin-induced electron spin relaxations in nanodiamonds,"Nanodiamonds (NDs) hosting nitrogen-vacancy (NV) centers are promising for
applications of quantum sensing. Long spin relaxation times ($T_1$ and $T_2$)
are critical for high sensitivity in quantum applications. It has been shown
that fluctuations of magnetic fields due to surface spins strongly influences
$T_1$ and $T_2$ in NDs. However, their relaxation mechanisms have yet to be
fully understood. In this paper, we investigate the relation between surface
spins and $T_1$ and $T_2$ of single-substitutional nitrogen impurity (P1)
centers in NDs. The P1 centers located typically in the vicinity of NV centers
are a great model system to study the spin relaxation processes of the NV
centers. By employing high-frequency electron paramagnetic resonance (EPR)
spectroscopy, we verify that air annealing removes surface spins efficiently
and significantly reduces their contribution to $T_1$.",2008.03832v1
2016-12-06,Spin-Hall Torques Generated by Rare-Earth (Lanthanide) Thin Films,"We report an initial experimental survey of spin-Hall torques generated by
the rare-earth metals Gd, Dy, Ho, and Lu, along with comparisons to
first-principles calculations of their spin Hall conductivities. Using spin
torque ferromagnetic resonance (ST-FMR) measurements and DC-biased ST-FMR, we
estimate lower bounds for the spin-Hall torque ratio, $\xi_{SH}$, of $\approx$
0.04 for Gd, $\approx$ 0.05 for Dy, $\approx$ 0.14 for Ho, and $\approx$ 0.014
for Lu. The variations among these elements are qualitatively consistent with
results from first principles (density functional theory, DFT, in the local
density approximation with a Hubbard-U correction). The DFT calculations
indicate that the spin Hall conductivity is enhanced by the presence of the
partially-filled $f$ orbitals in Dy and Ho, which suggests a strategy to
further strengthen the contribution of the $f$ orbitals to the spin Hall effect
by shifting the electron chemical potential.",1612.01927v1
2016-12-21,Spin transitions driven by electric dipole spin resonance in fluorinated single- and bilayer-graphene quantum dots,"Spin transitions driven by a periodically varying electric potential in
dilute fluorinated graphene quantum dots are investigated. Flakes of monolayer
graphene are considered as well as electrostatic electron traps induced in
bilayer graphene. The stationary states are obtained within the tight-binding
approach and are used to the basis of eigenstates to describe the system
dynamics. The dilute fluorination of the top layer lifts the valley degeneracy
of the confined states and attenuates the orbital magnetic dipole moments due
to current circulation within the flake. Moreover, the spin-orbit coupling
introduced by the surface deformation of the top layer induced by the adatoms
allows spin flips to be driven by the AC electric field. For the bilayer
quantum dots the spin flip times is substantially shorter than the experimental
spin relaxation. Dynamical effects including many-photon and multilevel
transitions are also discussed.",1612.07001v1
2017-02-17,Spin-pumping through a varying-thickness MgO interlayer in Fe/Pt system,"The spin-pumping mechanism is probed through a tunnelling MgO interlayer in
Fe/Pt bilayers. We show by ferromagnetic resonance technique and spin-pumping
experiments that spin currents can tunnel through the MgO interlayer for
thickness up to 2~{nm} and can produce significant voltages in the Pt layer.
The electrical detection of spin-pumping furthermore reveals the critical role
of rectification and shunting effects on the generated voltages. The non zero
spin current transport through a few monolayers of an insulating interlayer
might initiate further studies on the role of very thin oxides in spin-pumping
experiments.",1702.05298v1
2017-10-24,Electrical spin driving by $g$-matrix modulation in spin-orbit qubits,"In a semiconductor spin qubit with sizable spin-orbit coupling, coherent spin
rotations can be driven by a resonant gate-voltage modulation. Recently, we
have exploited this opportunity in the experimental demonstration of a hole
spin qubit in a silicon device. Here we investigate the underlying physical
mechanisms by measuring the full angular dependence of the Rabi frequency as
well as the gate-voltage dependence and anisotropy of the hole $g$-factors. We
show that a $g$-matrix formalism can simultaneously capture and discriminate
the contributions of two mechanisms so far independently discussed in the
literature: one associated with the modulation of the $g$ factors, and
measurable by Zeeman energy spectroscopy, the other not. Our approach has a
general validity and can be applied to the analysis of other types of
spin-orbit qubits.",1710.08690v2
2017-10-26,Itinerant spin fluctuations in iron-based superconductors,"Multiband systems, which possess a wide parameter space, allow to explore a
variety of competing ground states. Bright examples are the Fe-based pnictides
and chalcogenides, which demonstrate metallic, superconducting, and various
magnetic phases. Here I discuss only one of the many interesting topics,
namely, spin fluctuations in metallic multiband systems. I show how to
calculate the effect of itinerant spin excitations on the electronic properties
and formulate a theory of spin fluctuation-induced superconductivity. The
superconducting state is unconventional and thus the system demonstrates
unusual spin response with the spin resonance feature. I discuss its origin,
consequences, and relation to experimental observations. Role of the spin-orbit
coupling is specifically emphasized.",1710.09888v1
2019-03-14,Electrical control of spin mixing conductance in a Y$_3$Fe$_5$O$_{12}$/Platinum bilayer,"We report a tunable spin mixing conductance, up to $\pm 22\%$, in a
Y${}_{3}$Fe${}_{5}$O${}_{12}$/Platinum (YIG/Pt) bilayer.This control is
achieved by applying a gate voltage with an ionic gate technique, which
exhibits a gate-dependent ferromagnetic resonance line width. Furthermore, we
observed a gate-dependent spin pumping and spin Hall angle in the Pt layer,
which is also tunable up to $\pm$ 13.6\%. This work experimentally demonstrates
spin current control through spin pumping and a gate voltage in a YIG/Pt
bilayer, demonstrating the crucial role of the interfacial charge density for
the spin transport properties in magnetic insulator/heavy metal bilayers.",1903.05865v1
2020-09-03,"Odd-spin glueballs, AdS/QCD and information entropy","Odd-spin glueballs in the dynamical AdS/QCD model are scrutinized, in the
paradigm of the configurational entropy (CE). Configurational-entropic Regge
trajectories, that relate the CE underlying odd-spin glueballs to their mass
spectra and spin, are then engendered. They predict the mass spectra of
odd-spin glueballs, besides pointing towards the configurational stability of
odd-spin glueball resonances. The exponential modified dilaton with logarithmic
anomalous dimensions comprises the most suitable choice to derive the mass
spectra of odd-spin glueballs, compatible to lattice QCD. It is then used in a
hybrid paradigm that takes both lattice QCD and the AdS/QCD correspondence into
account.",2009.01890v2
2020-09-28,Determination of spin-orbit torques by thickness-dependent spin-orbit torque FMR measurement,"Current induced spin-orbit torques (SOTs) in Fe/Pt bilayers have been
investigated utilizing the spin-orbit torque ferromagnetic resonance (SOT-FMR)
measurement. Characterization of thin films with different thicknesses
indicates existence of a sizable field-like spin-orbit torque competing with
the Oersted field induced torque (Oersted torque). The field-like torque is
neglected in the standard SOT-FMR method and the presence of a strong
field-like torque makes estimation of the spin Hall angle (SHA) problematic.
Also, it is challenging to differentiate the field-like torque from the Oersted
torque in a radiofrequency measurement. Based on the thickness dependence of
field-like torque, anti-damping torque, and Oersted torque, the
thickness-dependent SOT-FMR measurement is proposed as a more reliable,
self-calibrated approach for characterization of spin-orbit torques.",2009.13162v2
2020-11-12,"Edge states in quantum spin chains: the interplay among interaction, gradient magnetic field and Floquet engineering","We explore the edge defects induced by spin-spin interaction in a finite
paradigmatic Heisenberg spin chain. By introducing a gradient magnetic field
and a periodically-modulated spin-exchange strength, the resonance between
modulation frequency and magnetic field gradient can also induce asymmetric
defects at the edges, dubbed as Floquet-Wannier-Zeeman edge defects. The
interplay between these two types of edge defects allows us to manipulate the
magnon edge states from an isolated band into a continuum one. In the
high-frequency regime, we analytically derive effective models to interpret the
formation mechanisms for edge states by employing the multiscale perturbation
analysis. Our study offers new insights to understand and control the magnon
edge states governed by the interplay between edge defects induced by the
spin-spin interaction and the Floquet-Wannier-Zeeman manipulation.",2011.06164v4
2019-07-13,Ab initio modelling of spin relaxation lengths in disordered graphene nanoribbons†,"The spin-dependent transport properties of armchair graphene nanoribbons in
the presence of extrinsic spin-orbit coupling induced by a random distribution
of Nickel adatoms is studied. By combining a recursive Green's function
formalism with density functional theory, we explore the influence of ribbon
length and metal adatom concentration on the conductance. At a given length, we
observed a significant enhancement of the spin-flip channel around resonances
and at energies right above the Fermi level. We also estimate the
spin-relaxation length, finding values on the order of tens of micrometers at
low Ni adatom concentrations. This study is conducted at singular ribbon
lengths entirely from fully ab-initio methods, providing indirectly evidence
that the Dyakonov-Perel spin relaxation mechanism might be the dominant at low
concentrations as well as the observation of oscillations in the
spin-polarization.",1907.05979v1
2019-12-09,NMR study of the spin excitations in the frustrated antiferromagnet Yb(BaBO$_3$)$_3$ with a triangular lattice,"In this paper, we study the spin excitation properties of the frustrated
triangular-lattice antiferromagnet Yb(BaBO$_3$)$_3$ with nuclear magnetic
resonance. From the spectral analysis, neither magnetic ordering nor spin
freezing is observed with temperature down to $T=0.26$ K, far below its
Curie-Weiss temperature $|\theta_w|\sim2.3$ K. From the nuclear relaxation
measurement, precise temperature-independent spin-lattice relaxation rates are
observed at low temperatures under a weak magnetic field, indicating the
gapless spin excitations. Further increasing the field intensity, we observe a
spin excitation gap with the gap size proportional to the field intensity.
These phenomena suggest a very unusual strongly correlated quantum disordered
phase, and the implications for the quantum spin liquid state are further
discussed.",1912.03814v2
2019-12-13,Pulse-width-induced polarization enhancement of optically-pumped N-V electron spin in diamond,"The nitrogen-vacancy (N-V) center in diamond is a widely-used platform for
quantum information processing and metrology. The electron-spin state of N-V
center could be initialized and readout optically, and manipulated by resonate
microwave fields. In this work, we analyze the dependence of electron-spin
initialization on widths of laser pulses. We build a numerical model to
simulate this process and verify the simulation results in experiment. Both
simulations and experiments reveal a fact that shorter laser pulses are helpful
to the electron-spin polarization. We therefore propose to use extremely-short
laser pulses for electron-spin initialization. In this new scheme, the
spin-state contrast could be improved about 10% in experiment by using laser
pulses as short as 4 ns in width. Furthermore, we provide a mechanism to
explain this effect which is due to the occupation time in the meta-stable
spin-singlet states of N-V center. Our new scheme is applicable in a broad
range of NV-based applications in the future.",1912.06284v1
2020-01-14,Hole spin in tunable Ge hut wire double quantum dot,"Holes in germanium (Ge) exhibit strong spin-orbit interaction, which can be
exploited for fast and all-electrical manipulation of spin states. Here, we
report transport experiments in a tunable Ge hut wire hole double quantum dot.
We observe the signatures of Pauli spin blockade (PSB) with a large
singlet-triplet energy splitting of ~1.1 meV and extract the g factor. By
analyzing the the PSB leakage current, we obtain a spin-orbit length l_so of ~
40-100 nm. Furthermore, we demonstrate the electric dipole spin resonance.
These results lay a solid foundation for implementing high quality tunable hole
spin-orbit qubits.",2001.04834v2
2020-05-06,Sub-Nanosecond Spin-Transfer Torque in an Ensemble of Superparamagnetic-Like Nanomagnets,"Spin currents can exert spin-transfer torques on magnetic systems even in the
limit of vanishingly small net magnetization, as is the case for
antiferromagnets. Here, we experimentally show that a spin-transfer torque is
operative in a material with weak, short-range magnetic order -- namely, a
macroscopic ensemble of superparamagnetic-like Co nanomagnets. We employ
element- and time-resolved X-ray ferromagnetic resonance (XFMR) spectroscopy to
directly detect sub-ns dynamics of the Co nanomagnets, excited into precession
with cone angle $\geq$0.003$^{\circ}$ by an oscillating spin current. XFMR
measurements reveal that as the net moment of the ensemble decreases, the
strength of the spin-transfer torque increases relative to those of magnetic
field torques. Our findings point to spin-transfer torque as an effective way
to manipulate the state of nanomagnet ensembles at sub-ns timescales.",2005.03081v1
2020-05-14,High-bandwidth microcoil for fast nuclear spin control,"The active manipulation of nuclear spins with radio-frequency (RF) coils is
at the heart of nuclear magnetic resonance (NMR) spectroscopy and spin-based
quantum devices. Here, we present a microcoil transmitter system designed to
generate strong RF pulses over a broad bandwidth, allowing for fast spin
rotations on arbitrary nuclear species. Our design incorporates: (i) a planar
multilayer geometry that generates a large field of 4.35 mT per unit current,
(ii) a 50 Ohm transmission circuit with a broad excitation bandwidth of
approximately 20 MHz, and (iii) an optimized thermal management for removal of
Joule heating. Using individual 13C nuclear spins in the vicinity of a diamond
nitrogen-vacancy (NV) center as a test system, we demonstrate Rabi frequencies
exceeding 70 kHz and nuclear pi/2 rotations within 3.4 us. The extrapolated
values for 1H spins are about 240 kHz and 1 us, respectively. Beyond enabling
fast nuclear spin manipulations, our microcoil system is ideally suited for the
incorporation of advanced pulse sequences into micro- and nanoscale NMR
detectors operating at low (<1 T) magnetic field.",2005.06837v1
2020-05-16,Simultaneous observation of anti-damping and inverse spin Hall effect in La$_{0.67}$Sr$_{0.33}$MnO$_{3}$/Pt bilayer system,"Manganites have shown potential in spintronics because they exhibit high spin
polarization. Here, by ferromagnetic resonance we have studied the damping
properties of La$_{0.67}$Sr$_{0.33}$MnO$_{3}$/Pt bilayers which are prepared by
oxide molecular beam epitaxy. The damping coefficient ($\alpha$) of
La$_{0.67}$Sr$_{0.33}$MnO$_{3}$ (LSMO) single layer is found to be 0.0104.
However the LSMO/Pt bilayers exhibit decrease in $\alpha$ with increase in Pt
thickness. This decrease in the value of $\alpha$ is probably due to high
anti-damping like torque. Further, we have investigated the angle dependent
inverse spin Hall effect (ISHE) to quantify the spin pumping voltage from other
spin rectification effects such as anomalous Hall effect and anisotropic
magnetoresistance. We have observed high spin pumping voltage ($\sim$~20 $ \mu
V$). The results indicate that both anti-damping and spin pumping phenomena are
occuring simultaneously.",2005.07848v3
2020-05-18,Pseudospin-electric coupling for holes beyond the envelope-function approximation,"In the envelope-function approximation, interband transitions produced by
electric fields are neglected. However, electric fields may lead to a spatially
local ($k$-independent) coupling of band (internal, pseudospin) degrees of
freedom. Such a coupling exists between heavy-hole and light-hole (pseudo-)spin
states for holes in III-V semiconductors, such as GaAs, or in group IV
semiconductors (germanium, silicon, ...) with broken inversion symmetry. Here,
we calculate the electric-dipole (pseudospin-electric) coupling for holes in
GaAs from first principles. We find a transition dipole of $0.5$ debye, a
significant fraction of that for the hydrogen-atom $1s\to2p$ transition. In
addition, we derive the Dresselhaus spin-orbit coupling that is generated by
this transition dipole for heavy holes in a triangular quantum well. A
quantitative microscopic description of this pseudospin-electric coupling may
be important for understanding the origin of spin splitting in quantum wells,
spin coherence/relaxation ($T_2^*/T_1$) times, spin-electric coupling for
cavity-QED, electric-dipole spin resonance, and spin non-conserving tunneling
in double quantum dot systems.",2005.08821v2
2020-12-23,Spin noise spectroscopy of a noise-squeezed atomic state,"Spin noise spectroscopy is emerging as a powerful technique for studying the
dynamics of various spin systems also beyond their thermal equilibrium and
linear response. Here, we study spin fluctuations of room-temperature neutral
atoms in a Bell-Bloom type magnetometer. Driven by indirect pumping and
undergoing a parametric excitation, this system is known to produce
noise-squeezing. Our measurements not only reveal a strong asymmetry in the
noise distribution of the atomic signal quadratures at the magnetic resonance,
but also provide insight into the mechanism behind its generation and
evolution. In particular, a structure in the spectrum is identified which
allows to investigate the main dependencies and the characteristic timescales
of the noise process. The results obtained are compatible with parametrically
induced noise squeezing. Notably, the noise spectrum provides information on
the spin dynamics even in regimes where the macroscopic atomic coherence is
lost, effectively enhancing the sensitivity of the measurements. Our work
promotes spin noise spectroscopy as a versatile technique for the study of
noise squeezing in a wide range of spin based magnetic sensors.",2012.12617v1
2021-03-04,X-Ray Scattering from Light-Driven Spin Fluctuations in a Doped Mott Insulator,"Manipulating spin fluctuations with ultrafast laser pulses is a promising
route to dynamically control collective phenomena in strongly correlated
materials. However, understanding how photoexcited spin degrees of freedom
evolve at a microscopic level requires a momentum- and energy-resolved
characterization of their nonequilibrium dynamics. Here, we study the
photoinduced dynamics of finite-momentum spin excitations in two-dimensional
Mott insulators on a square lattice. By calculating the time-resolved resonant
inelastic x-ray scattering cross-section, we show that an ultrafast pump above
the Mott gap induces a prompt softening of the spin excitation energy,
compatible with a transient renormalization of the exchange interaction. While
spin fluctuations in a hole-doped system (paramagnons) are well described by
Floquet theory, magnons at half filling are found to deviate from this picture.
Furthermore, we show that the paramagnon softening is accompanied by an
ultrafast suppression of $d$-wave pairing correlations, indicating a link
between the transient spin excitation dynamics and superconducting pairing far
from equilibrium.",2103.03369v2
2021-05-01,Interacting electron spins in $κ$-(BEDT-TTF)$_2$Cu[N(CN)$_2$]I investigated by ESR spectroscopy,"We performed angular and temperature-dependent electron-spin-resonance
measurements in the quasi-two-dimensional organic conductor
$\kappa$-(BEDT-TTF)$_2$Cu[N(CN)$_2$]I. The interlayer spin-diffusion is much
weaker compared to the Cl- and Br-analogues, which are antiferromagnetic
insulator and paramagnetic metal, respectively;
$\kappa$-(BEDT-TTF)$_2$Cu[N(CN)$_2$]I behaves insulating when cooled below $T$
= 200 K. A spin gap ($\Delta\approx$ 18 K) opens at low temperatures leading to
a spin-singlet state. Due to intrinsic disorder a substantial number of spins
($\sim$ 1 $\%$) remains unpaired. We observe additional signals below $T$ = 4 K
with a pronounced anisotropy indicating the presence of local magnetic moments
coupled to some fraction of those unpaired spins.",2105.00251v1
2021-12-16,Decoupling of Spin Decoherence Paths near Zero Magnetic Field,"We demonstrate a method to quantify and manipulate nuclear spin decoherence
mechanisms that are active in zero to ultralow magnetic fields. These include:
(i) non-adiabatic switching of spin quantization axis, due to residual
background fields; (ii) scalar pathways due to through-bond couplings between
$^1$H and heteronuclear spin species, such as $^2$H used partially as an
isotopic substitute for $^1$H. Under conditions of free evolution, scalar
relaxation due to $^2$H can significantly limit nuclear spin polarization
lifetimes and thus the scope of magnetic resonance procedures near zero field.
It is shown that robust trains of pulsed dc magnetic fields that apply $\pi$
flip angles to one or multiple spin species may switch effective symmetry of
the nuclear spin Hamiltonian, imposing decoupled or coupled dynamic regimes on
demand. The method should broaden the spectrum of hyperpolarized biomedical
contrast-agent compounds and hyperpolarization procedures that are used near
zero field.",2112.08536v1
2022-02-03,Element Doping Enhanced Charge-to-Spin Conversion Efficiency in Amorphous PtSn4 Dirac Semimetal,"Topological semimetals (TSs) are promising candidates for low-power
spin-orbit torque (SOT) devices due to their large charge-to-spin conversion
efficiency. Here, we investigated the charge-to-spin conversion efficiency of
amorphous PtSn4 (5 nm)/CoFeB (2.5-12.5 nm) layered structures prepared by a
magnetron sputtering method at room temperature. The charge-to-spin ratio of
PtSn4/CoFeB bilayers was 0.08, characterized by a spin torque ferromagnetic
resonance (ST-FMR) technique. This ratio can further increase to 0.14 by
inducing dopants, like Al and CoSi, into PtSn4. The dopants can also decrease
(Al doping) or increase (CoSi doping) the resistivity of PtSn4. The work
proposed a way to enhance the spin-orbit coupling (SOC) in amorphous TSs with
dopants.",2202.01384v1
2022-02-08,"Spin-Phonon Relaxation in Magnetic Molecules: Theory, Predictions and Insights","Magnetic molecules have played a central role in the development of magnetism
and coordination chemistry and their study keeps leading innovation in
cutting-edge scientific fields such as magnetic resonance, magnetism,
spintronics, and quantum technologies. Crucially, a long spin lifetime well
above cryogenic temperature is a stringent requirement for all these
applications. In this chapter we review the foundations of spin relaxation
theory and provide a detailed overview of first-principles strategies applied
to the problem of spin-phonon relaxation in magnetic molecules. Firstly, we
present a rigorous formalism of spin-phonon relaxation based on open quantum
systems theory. These results are then used to derive classical
phenomenological relations based on the Debye model. Finally, we provide a
prescription of how to map the relaxation formalism onto existing electronic
structure methods to obtain a quantitative picture of spin-phonon relaxation.
Examples from the literature, including both transition metals and lanthanides
compounds, will be discussed in order to illustrate how Direct, Orbach and
Raman relaxation mechanisms can affect spin dynamics for this class of
compounds.",2202.03776v1
2022-02-15,Selective measurement of the longitudinal electron spin relaxation time $T_1$ of Ce$^{3+}$ ions in a YAG lattice: Resonant spin inertia,"Electron spin oriented along an external magnetic field is subject to
longitudinal spin relaxation with characteristic time $T_1$. The corresponding
decay is nonoscillating, so one cannot readily ascribe $T_1$ to a certain $g$
factor. This becomes a problem when several electronic states with different
$g$ factors are present in the system, e.g. electrons and holes. We solve this
problem by optically pumping spin polarization and then selectively
depolarizing it using a radio frequency (rf) field. By modulating the rf field
one can observe the retarded modulation of spin polarization which depends on
the relation between the modulation period and $T_1$. Using this selective spin
inertia method, we unveil the strong anisotropy of $T_1$ for rare-earth
Ce$^{3+}$ ions in a YAG crystal at low temperatures and low magnetic fields. We
also show that the spread of Larmor frequencies within the electron ensemble in
this system is not static, but results from the fluctuations of internal
magnetic fields on a timescale much shorter than $T_1$.",2202.07223v2
2022-05-09,Direct and alternating magnon spin currents across a junction interface irradiated by linearly polarized laser,"The developments in the field of quantum optics raise expectations that
laser-matter coupling is a promising building block for magnonics. Here, we
propose a method for the generation of direct and alternating spin currents of
magnons across the junction interface irradiated by linearly polarized laser.
In a junction of ferromagnetic insulators with a large electronic gap, the spin
angular momentum is exchanged during the tunneling process of magnons across
the junction interface. The advanced technology in the field of plasmonics and
metamaterials realizes that spins irradiated by the laser field interact only
with the magnetic component of the laser through the Zeeman coupling. Using an
analytic perturbation theory, we provide a general formula for magnon transport
induced by the inversion symmetry breaking across the junction interface. Then,
we show that those spin currents are enhanced by the ferromagnetic resonance,
and the period of the ac spin current is one-half of that of the laser magnetic
field. Finally, we estimate the magnitude of the spin current, and find that it
will be within experimental reach.",2205.04572v1
2022-06-29,The role of electron polarization on nuclear spin diffusion,"Dynamic nuclear polarization (DNP) is capable of boosting signals in nuclear
magnetic resonance by orders of magnitude by creating out-of-equilibrium
nuclear spin polarization. The diffusion of nuclear spin polarization in the
vicinity of paramagnetic dopants is a crucial step for DNP and remains yet not
well understood. In this Letter, we show that the polarization of the electron
spin controls the rate of proton spin diffusion in a DNP sample at 1.2 K and 7
T; at increasingly high electron polarization, spin diffusion vanishes. We
rationalize our results using a 2 nucleus - 1 electron model and Lindblad s
Master equation, which generalizes preexisting models in the literature and
qualitatively accounts for the experimental observed spin diffusion dynamics.",2206.14771v1
2022-07-14,Spin relaxation dynamics of radical-pair processes at low magnetic fields,"We report measurements of room-temperature spin-relaxation times $T_1$ and
$T_2$ of charge-carrier spins in a $\pi$-conjugated polymer thin film under
bipolar injection and low ($1\mbox{ mT}\lesssim B_0\lesssim 10\mbox{ mT}$)
static magnetic fields, using electrically detected magnetic resonant Hahn-echo
and inversion-recovery pulse sequences. The experiments confirm the correlation
between the magnetic-field sensitive observables of radical-pair processes,
which include both the spin-dependent recombination currents in organic
semiconductors and the associated spin-relaxation times when random local
hyperfine fields and external magnetic fields compete in magnitude. Whereas a
striking field dependence of spin-lattice relaxation exists in the low-field
regime, the apparent spin decoherence time remains field independent as the
distinction between the two is lifted at low fields.",2207.07086v1
2022-08-10,Efficient spin-to-charge interconversion in Weyl semimetal TaP at room temperature,"In this paper we present spin-to-charge current conversion properties in the
Weyl semimetal TaP by means of the inverse Rashba-Edelstein effect (IREE) with
the integration of this quantum material with the ferromagnetic metal Permalloy
$(Py=Ni_{81}Fe_{19})$. The spin currents are generated in the Py layer by the
spin pumping effect (SPE) from microwave-driven ferromagnetic resonance and are
detected by a dc voltage along the TaP crystal, at room temperature. We observe
a field-symmetric voltage signal without the contamination of asymmetrical
lines due to spin rectification effects observed in studies using metallic
ferromagnets. The observed voltage is attributed to spin-to-charge current
conversion based on the IREE, made possible by the spin-orbit coupling induced
intrinsically by the bulk band structure of Weyl semimetals. The measured IREE
coefficient ${\lambda}_{IREE}=(0.30 \pm{0.01})$ nm is two orders of magnitude
larger than in graphene and is comparable to or larger than the values reported
for some metallic interfaces and for several topological insulators.",2208.05151v1
2022-08-29,Microwave fluorescence detection of spin echoes,"Counting the microwave photons emitted by an ensemble of electron spins when
they relax radiatively has recently been proposed as a sensitive method for
electron paramagnetic resonance (EPR) spectroscopy, enabled by the development
of operational Single Microwave Photon Detectors (SMPD) at millikelvin
temperature. Here, we report the detection of spin echoes in the spin
fluorescence signal. The echo manifests itself as a coherent modulation of the
number of photons spontaneously emitted after a $\pi/2_X - \tau - \pi_Y - \tau
- \pi/2_\Phi $ sequence, dependent on the relative phase $\Phi$. We demonstrate
experimentally this detection method using an ensemble of $\mathrm{Er}^{3+}$
ion spins in a scheelite crystal of $\mathrm{CaWO}_4$. We use
fluorescence-detected echoes to measure the erbium spin coherence time, as well
as the echo envelope modulation due to the coupling to the $^{183}\mathrm{W}$
nuclear spins surrounding each ion. We finally compare the signal-to-noise
ratio of inductively-detected and fluorescence-detected echoes, and show that
it is larger with the fluorescence method.",2208.13586v1
2022-09-15,Chasing the spin gap through the phase diagram of a frustrated Mott insulator,"The quest for entangled spin excitations has stimulated intense research on
frustrated magnetic systems. For almost two decades, the triangular-lattice
Mott insulator $\kappa$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$ has been the hottest
candidate for a $gapless$ quantum spin liquid with itinerant spinons. Very
recently, however, this scenario was overturned as electron-spin-resonance
(ESR) studies unveiled a spin gap, calling for reevaluation of the magnetic
ground state. Here we achieve a precise mapping of this spin-gapped phase
through the Mott transition by ultrahigh-resolution strain tuning. Our
transport experiments reveal a reentrance of charge localization below
$T^{\star}=6$ K associated with a gap size of 30-50 K. The negative slope of
the insulator-metal boundary, $dT^{\star}/dp<0$, evidences the low-entropy
nature of the spin-singlet ground state. By tuning the enigmatic '6 K anomaly'
through the phase diagram of $\kappa$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$, we identify
it as the transition to a valence-bond-solid phase, with typical magnetic and
structural fingerprints, that persists at $T\rightarrow 0$ until unconventional
superconductivity and metallic transport proliferate.",2209.07639v1
2022-10-25,Constant-adiabaticity ultralow magnetic field manipulations of parahydrogen-induced polarization: application to an AA'X spin system,"The field of magnetic resonance imaging with hyperpolarized contrast agents
is rapidly expanding, and parahydrogen-induced polarization (PHIP) is emerging
as an inexpensive and easy-to-implement method for generating the required
hyperpolarized biomolecules. Hydrogenative PHIP delivers hyperpolarized proton
spin order to a substrate via chemical addition of H2 in the spin-singlet
state, but prior to imaging it is typically necessary to transfer the proton
polarization to a heteronucleus (usually 13C) in the molecule. Adiabatic
ultralow magnetic field manipulations can be used to induce the polarization
transfer, but this is necessarily a slow process, which is undesirable since
the spins continually relax back to thermal equilibrium. Here we demonstrate
constant-adiabaticity field cycling and field sweeping for optimal polarization
transfer on a model AA$'$X spin system, [1-13C]fumarate. We introduce a method
for calculating constant-adiabaticity magnetic field ramps and demonstrate that
they enable much faster spin-order conversion as compared to linear ramps used
before. The present method can thus be utilized to manipulate nonthermal order
in heteronuclear spin systems.",2210.14342v1
2022-12-18,Exact Entanglement Dynamics of Two Spins in Finite Baths,"We consider the buildup and decay of two-spin entanglement through phase
interactions in a finite environment of surrounding spins, as realized in
quantum computing platforms based on arrays of atoms, molecules, or nitrogen
vacancy centers. The non-Markovian dephasing caused by the spin environment
through Ising-type phase interactions can be solved exactly and compared to an
effective Markovian treatment based on collision models. In a first case study
on a dynamic lattice of randomly hopping spins, we find that non-Markovianity
boosts the dephasing rate caused by nearest neighbour interactions with the
surroundings, degrading the maximum achievable entanglement. However, we also
demonstrate that additional three-body interactions can mitigate this
degradation, and that randomly timed reset operations performed on the two-spin
system can help sustain a finite average amount of steady-state entanglement.
In a second case study based on a model nuclear magnetic resonance system, we
elucidate the role of bath correlations at finite temperature on non-Markovian
dephasing. They speed up the dephasing at low temperatures while slowing it
down at high temperatures, compared to an uncorrelated bath, which is related
to the number of thermally accessible spin configurations with and without
interactions.",2212.09151v1
2023-01-02,Topological Kondo Superconductors,"Spin-triplet $p$-wave superconductors are promising candidates for
topological superconductors. They have been proposed in various
heterostructures where a material with strong spin-orbit interaction is coupled
to a conventional $s$-wave superconductor by proximity effect. However,
topological superconductors existing in nature and driven purely by strong
electron correlations are yet to be studied. Here we propose a realization of
such a system in a class of Kondo lattice materials in the absence of
spin-orbit coupling and proximity effect. Therein, the odd-parity Kondo
hybridization mediates ferromagnetic spin-spin coupling and leads to
spin-triplet resonant-valence-bond ($t$-RVB) pairing between local moments.
Spin-triplet $p\pm i p^\prime$-wave topological superconductivity is reached
when Kondo effect co-exists with $t$-RVB. We identify the topological nature by
the non-trivial topological invariant and the Majorana fermions at edges. Our
results offer a comprehensive understanding of experimental observations on
UTe$_2$, a U-based ferromagnetic heavy-electron superconductor.",2301.00538v1
2023-01-26,"Optical orientation of excitons in a longitudinal magnetic field in indirect band gap (In,Al)As/AlAs quantum dots with type-I band alignment","The exciton recombination and spin dynamics in (In,Al)As/AlAs quantum dots
(QDs) with indirect band gap and type-I band alignment are studied. The
negligible (less than $0.2~\mu$eV) value of the anisotropic exchange
interaction in these QDs prevents a mixing of the excitonic basis states with
pure spin and allows for the formation of spin polarized bright excitons for
quasi-resonant circularly polarized excitation. In a longitudinal magnetic
field, the recombination and spin dynamics of the excitons are controlled by
the hyperfine interaction between the electron and nuclear spins. A QD blockade
by dark excitons is observed in magnetic field eliminating the impact of the
nuclear spin fluctuations. A kinetic equation model, which accounts for the
population dynamics of the bright and dark exciton states as well as for the
spin dynamics, has been developed, which allows for a quantitative description
of the experimental data.",2301.11138v1
2023-05-18,Giant optical orientation of exciton spins in lead halide perovskite crystals,"Optical orientation of carrier spins by circularly polarized light is the
basis of spin physics in semiconductors. Here, we demonstrate strong optical
orientation of 85\%, approaching the ultimate limit of unity, for excitons in
FA$_{0.9}$Cs$_{0.1}$PbI$_{2.8}$Br$_{0.2}$ lead halide perovskite bulk crystals.
Time-resolved photoluminescence allows us to distinguish excitons with 60~ps
lifetime from electron-hole recombination in the spin dynamics detected via
coherent spin quantum beats in magnetic field. We reveal electron-hole spin
correlations through linear polarization beats after circularly polarized
excitation. Detuning of the excitation energy from the exciton resonance up to
0.5~eV does not reduce the optical orientation, evidencing clean chiral
selection rules in agreement with atomistic calculations, and suppressed spin
relaxation of electrons and holes even with large kinetic energies.",2305.10875v1
2023-10-10,Modulating Resonant Electronic Coupling of Tungsten Diselenide Monolayers with Vanadyl Phthalocyanine for Spin-Valley Polarization Control,"Combining the synthetic tunability of molecular compounds with the optical
selection rules of transition metal dichalcogenides (TMDC) that derive from
spin-valley coupling could provide interesting opportunities for the readout of
quantum information. However, little is known about the electronic and spin
interactions at such interfaces and the influence on spin-valley relaxation. In
this work we investigate various heterojunctions of vanadyl phthalocyanine
(VOPc) thermally evaporated on WSe$_2$ and find that local ordering of the
molecular layer plays an important role in the electronic perturbation of
WSe$_2$, which in turn directly influences the spin-valley polarization
lifetime. A thin molecular layer results in a hybrid state which destroys the
spin-valley polarization almost instantaneously, whereas a thicker molecular
layer with well-defined local ordering shows minimal electronic perturbation
and results in longer-lived spin-valley polarization than the WSe$_2$ monolayer
alone.",2310.06979v1
2023-10-25,Spin-photon entanglement with direct photon emission in the telecom C-band,"The ever-evolving demands for computational power and for a securely
connected world dictate the development of quantum networks where entanglement
is distributed between connected parties. Solid-state quantum emitters in the
telecom C-band are a promising platform for quantum communication applications
due to the minimal absorption of photons at these wavelengths, ""on-demand""
generation of single photon flying qubits, and ease of integration with
existing network infrastructure. Here, we use an InAs/InP quantum dot to
implement an optically active spin-qubit, based on a negatively charged exciton
where the electron spin degeneracy is lifted using a Voigt magnetic field. We
investigate the coherent interactions of the spin-qubit system under resonant
excitation, demonstrating high fidelity spin initialisation and coherent
control using picosecond pulses. We further use these tools to measure the
coherence of a single, undisturbed electron spin in our system. Finally, we
report the first demonstration of spin-photon entanglement in a solid-state
system capable of direct emission into the telecom C-band.",2310.16930v1
2023-11-10,Spin noise of a halide perovskite,"We report on first observation of spin noise in a strongly birefringent
semiconductor -- halide perovskite single crystal MAPbI$_3$. The observed spin
noise resonance is ascribed to free holes with a record spin dephasing time of
4 ns. The spin dynamics is found to be affected by the residual light
absorption of the crystal providing renormalization of the Larmor frequency.
Extended spin noise spectroscopy with rotating magnetic field allowed us not
only to evaluate the $g$-factor anisotropy, but also to distinguish two
different spin subsystems tentatively associated to twinning of the crystal.",2311.06077v1
2024-01-26,Protocol for certifying entanglement in surface spin systems using a scanning tunneling microscope,"Certifying quantum entanglement is a critical step towards realizing
quantum-coherent applications of surface spin systems. In this work, we show
that entanglement can be unambiguously shown in a scanning tunneling microscope
(STM) with electron spin resonance by exploiting the fact that entangled states
undergo a free time evolution with a distinct characteristic time constant that
clearly distinguishes it from any other time evolution in the system. By
implementing a suitable phase control scheme, the phase of this time evolution
can be mapped back onto the population of one entangled spin in a pair, which
can then be read out reliably using a weakly coupled sensor spin in the
junction of the scanning tunneling microscope. We demonstrate through open
quantum system simulations with realistic spin systems, which are currently
available with spin coherence times of $T_2\approx$ 300 ns, that a signal
directly correlated with the degree of entanglement can be measured at a
temperature range of 100$-$400 mK accessible in sub-Kelvin cryogenic STM
systems.",2401.15017v1
2024-04-15,Optical probing of the carriers-mediated coupling of the spin of two Co atoms in a quantum dot,"We report on the optical spectroscopy of the spin of two Co atoms in a
quantum dot and interacting with a single exciton. The spectrum of quantum dots
containing two Co atoms are exchange interaction and by the strain at the
location of the magnetic atoms. A wide range of spectrum can be obtained
depending on the relative coupling of each atom to the confined exciton. We
obtained a comprehensive interpretation of the experimental data with a spin
Hamiltonian model. We show that the two Co atoms spins can be orientated by the
injection of spin polarized carriers at zero magnetic field. This induces a
correlation between the two spins that is observed in the intensity
distribution of the emission spectra. The optical absorption in the phonon
sideband of quantum dots doped with two Co reveals resonant absorptions which
strongly depend on a transverse magnetic field. We show that these
characteristic absorptions result from an interplay between the mixing of Co
spin states induced by the presence of in-plane strain anisotropy at the
magnetic atoms location and the transverse field.",2404.09534v1
2019-03-20,A nonreciprocal optical resonator with broken time-invariance for arbitrarily high time-bandwidth performance,"Most present-day resonant systems, throughout physics and engineering, are
characterized by a strict time-reversal symmetry between the rates of energy
coupled in and out of the system, which leads to a trade-off between how long a
wave can be stored in the system and the system bandwidth. Any attempt to
reduce the losses of the resonant system, and hence store a (mechanical,
acoustic, electronic, optical, atomic, or of any other nature) wave for more
time, will inevitably also reduce the bandwidth of the system. Until recently,
this time-bandwidth limit has been considered fundamental, arising from basic
Fourier reciprocity. A recent theory suggested that it might in fact be
overcome by breaking Lorentz reciprocity in the resonant system, reinvigorated
a debate about whether (or not) this was indeed the case. Here, we report an
experimental realization of a cavity where, inducing nonreciprocity by breaking
the time invariance, we do overcome the fundamental time-bandwidth limit of
ordinary resonant systems by a factor of 30, in full agreement with
accompanying numerical simulations. We show that, although in practice
experimental constraints limit our scheme, the time bandwidth product can be
arbitrarily large, simply dictated by the finesse of the cavity. Our
experimental realization uses a simple macroscopic, time-variant, fiber-optic
cavity, where we break Lorentz reciprocity by non-adiabatically opening the
cavity, injecting a pulse of large bandwidth, and then closing the cavity,
storing the pulse which can be released on-demand at a later time. Our results
open the path for designing resonant systems, ubiquitous in physics and
engineering, that can simultaneously be broadband (i.e., ultrafast) and
possessing long storage times, thereby unleashing fundamentally new
functionalities in wave physics and wave-matter interactions.",1903.08386v2
2020-07-17,Gravitational wave detectors with broadband high frequency sensitivity,"The binary neutron star coalescence GW170817 was observed by gravitational
wave detectors during the inspiral phase but sensitivity in the 1-5 kHz band
was insufficient to observe the expected nuclear matter signature of the merger
itself, and the process of black hole formation. This provides strong
motivation for improving 1--5 kHz sensitivity which is currently limited by
photon shot noise. Resonant enhancement by signal recycling normally improves
the signal to noise ratio at the expense of bandwidth. The concept of
optomechanical white light signal recycling (WLSR) has been proposed, but all
schemes to date have been reliant on the development of suitable ultra-low
mechanical loss components. Here for the first time we show demonstrated
optomechanical resonator structures that meet the loss requirements for a WLSR
interferometer with strain sensitivity below 10$^{-24}$ Hz$^{-1/2}$ at a few
kHz. Experimental data for two resonators are combined with analytic models of
4km interferometers similar to LIGO, to demonstrate sensitivity enhancement
across a much broader band of neutron star coalescence frequencies than
dual-recycled Fabry-Perot Michelson detectors of the same length. One candidate
resonator is a silicon nitride membrane acoustically isolated from the
environment by a phononic crystal. The other is a single-crystal quartz lens
that supports bulk acoustic longitudinal waves. Optical power requirements
could prefer the membrane resonator, although the bulk acoustic wave resonator
gives somewhat better thermal noise performance. Both could be implemented as
add-on components to existing detectors.",2007.08766v1
2023-05-15,Extreme mass-ratio inspiral of a spinning body into a Kerr black hole I: Evolution along generic trajectories,"The study of spinning bodies moving in curved spacetime has relevance to
binary black hole systems with large mass ratios, as well as being of formal
interest. At zeroth order in a binary's mass ratio, the smaller body moves on a
geodesic of the larger body's spacetime. Post-geodesic corrections describing
forces driving the small body's worldline away from geodesics must be
incorporated to model the system accurately. An important post-geodesic effect
is the gravitational self-force, which describes the small body's interaction
with its own spacetime curvature. This effect includes the backreaction due to
gravitational-wave emission that leads to the inspiral of the small body into
the black hole. When a spinning body orbits a black hole, its spin couples to
spacetime curvature. This introduces another post-geodesic correction known as
the spin-curvature force. An osculating geodesic integrator that includes both
the backreaction due to gravitational waves and spin-curvature forces can be
used to generate a spinning-body inspiral. In this paper, we use an osculating
geodesic integrator to combine the leading backreaction of gravitational waves
with the spin-curvature force. Our analysis only includes the leading
orbit-averaged dissipative backreaction, and examines the spin-curvature force
to leading order in the small body's spin. This is sufficient to build generic
inspirals of spinning bodies, and serves as a foundation for further work
examining how to include secondary spin in large-mass-ratio waveform models.",2305.08919v2
2014-10-31,Spin-orbit coupling in fluorinated graphene,"We report on theoretical investigations of the spin-orbit coupling effects in
fluorinated graphene. First-principles density functional calculations are
performed for the dense and dilute adatom coverage limits. The dense limit is
represented by the single-side semifluorinated graphene, which is a metal with
spin-orbit splittings of about 10 meV. To simulate the effects of a single
adatom, we also calculate the electronic structure of a $10 \times 10$
supercell, with one fluorine atom in the top position. Since this dilute limit
is useful to study spin transport and spin relaxation, we also introduce a
realistic effective hopping Hamiltonian, based on symmetry considerations,
which describes the supercell bands around the Fermi level. We provide the
Hamiltonian parameters which are best fits to the first-principles data. We
demonstrate that, unlike for the case of hydrogen adatoms, fluorine's own
spin-orbit coupling is the principal cause of the giant induced local
spin-orbit coupling in graphene. The $sp^3$ hybridization induced transfer of
spin-orbit coupling from graphene's $\sigma$ bonds, important for hydrogenated
graphene, contributes much less. Furthermore, the magnitude of the induced
spin-orbit coupling due to fluorine adatoms is about $1000$ times more than
that of pristine graphene, and 10 times more than that of hydrogenated
graphene. Also unlike hydrogen, the fluorine adatom is not a narrow resonant
scatterer at the Dirac point. The resonant peak in the density of states of
fluorinated graphene in the dilute limit lies 260 meV below the Dirac point.
The peak is rather broad, about 300 meV, making the fluorine adatom only a
weakly resonant scatterer.",1411.0016v2
2018-02-20,Reverse Monte Carlo reconstruction of electron spin-label coordinates from scanned-probe magnetic resonance microscope signals,"Individual electron spins have been observed using magnetic resonance in
combination with a number of distinct detection approaches. The coordinates of
an individual electron spin can then in principle be determined by introducing
a 10 to 100 nm diameter magnetic needle, scanning the needle, and collecting
signal as a function of the needle's position. Although individual electrons
have recently been localized with nanometer precision in this way using a
nitrogen-vacancy center in diamond as the spin detector, the experiment's low
signal-to-noise ratio limited acquisition to two-dimensional scanning of just a
few dozen data points and was incompatible with nitroxide spin labels widely
used to label proteins and nucleic acids. We introduce and numerically simulate
a protocol for detecting and imaging individual nitroxide electron spins
mechanically with high spatial resolution. In our protocol a scanned
magnet-tipped cantilever is brought near the sample, modulated microwaves are
applied to resonantly excite electron spins, and changes in spin magnetization
are detected as a shift in the mechanical frequency of the cantilever. By
carefully applying resonant microwaves in short bursts in synchrony with the
cantilever's oscillation, we propose to retain high spatial resolution even at
large cantilever amplitude where sensitivity is highest. Numerical simulations
reveal nanometer-diameter rings of frequency-shift signal as the tip is
scanned. Our primary finding is that it is possible --- using a Bayesian,
reverse Monte Carlo algorithm introduced here --- to obtain the full
three-dimensional distribution of electron coordinates from the signal rings
revealed in a two-dimensional frequency-shift map. This reduction in
dimensionality brings within reach, on a practical timescale, the
angstrom-resolution three-dimensional imaging of spin-labeled macromolecules.",1802.07247v1
2020-11-26,Direct high resolution resonant Raman scattering measurements of InAs quantum dot dynamic nuclear spin polarization states,"We report on the direct measurement of the electron spin splitting and the
accompanying nuclear Overhauser (OH) field, and thus the underlying nuclear
spin polarization (NSP) and fluctuation bandwidth, in a single InAs quantum dot
under resonant excitation conditions with unprecedented spectral resolution.
The electron spin splitting is measured directly via resonant spin-flip single
photon Raman scattering detected by superconducting nanowires to generate
excitation-emission energy maps. The observed two-dimensional maps reveal an OH
field that has a non-linear dependence on excitation frequency. This study
provides new insight into earlier reports of so-called avoidance and tracking,
showing two distinct NSP responses directly by the addition of a emission
energy axis. The data show that the polarization processes depend on which
electron spin state is optically driven, with surprising differences in the
polarization fluctuations for each case: in one case, a stabilized field
characterized by a single-peaked distribution shifts monotonically with the
laser excitation frequency resulting in a nearly constant optical interaction
strength across a wide detuning range, while in the other case the previously
reported avoidance behavior is actually the result of a nonlinear dependence on
the laser excitation frequency near zero detuning leading to switching between
two distinct mesoscopic nuclear spin states. The magnitude of the field, which
is as large as 400 mT, is measured with sub-100 nuclear spin sensitivity.
Stable/unstable points of the OH field distribution are observed, resulting
from the non-linear feedback loop in the electron-trion-nuclear system. Nuclear
spin polarization state switching occurs between fields differing by 160 mT at
least as fast as 25 ms. Control experiments indicate that the strain-induced
quadrupolar interaction may explain the measured OH fields.",2011.13249v1
2020-12-29,Coherent single-spin electron resonance spectroscopy manifested at an exceptional-point singularity in a doped polyacetylene,"Spin-dependent charge transfer decay in an alkali atom doped polyacetylene is
studied in terms of the complex spectral analysis, revealing the single-spin
Zeeman splitting influenced by the spin-orbit interaction. Nonhermitian
effective Hamiltonian has been derived from the total system hermitian
Hamiltonian using Brillouin-Wigner-Feshbach projection method, where the
microscopic spin-dependent dissipation effect is correctly incorporated in the
energy-dependent self-energy. Since the present method maintains the dynamical
and chiral symmetries of the total system, we discovered two types of
exceptional point (EP) singularities in a unified perspective: the EP surface
and EP ring are attributed to the dynamical and chiral symmetry breaking,
respectively. We have revealed that the coherent single-spin electron resonance
(SSESR) spectrum reflects the complex eigenenergy spectrum of the system. We
have formulated the SSESR spectrum in terms of the nonlinear response function
in the Liouville-space pathway approach, where we have constructed the
Liouville space basis using the complex eigenstates of the total Hamiltonian.
We have calculated the one- and two-dimensional Fourier transform SSESR (1DFT
and 2DFT) spectra reflecting the spin-relaxation dynamics at the donor site.
While the 1DFT SSESR spectrum reflects the complex eigenenergy spectrum, the
2DFT gives detailed information on the quantum coherence in the spin-relaxation
dynamics as a cross-correlation between the two frequencies. We found a giant
response of the coherent SSESR around the EP ring singularity due to the
vanishing normalization factors at the EP ring and the resonance effect. We
have discovered that the giant response is much larger in magnitudes in the
2DFT spectrum than in the 1DFT spectrum, which promises the 2DFT SSESR a useful
tool to observe the single-spin response in a molecule.",2012.14655v1
2011-03-31,Acoustic spin pumping as the origin of the long-range spin Seebeck effect,"The spin Seebeck effect (SSE) is known as the generation of 'spin voltage' in
a magnet as a result of a temperature gradient. Spin voltage stands for the
potential for spins, which drives a spin current. The SSE is of crucial
importance in spintronics and energy-conversion technology, since it enables
simple and versatile generation of spin currents from heat. The SSE has been
observed in a variety of materials ranging from magnetic metals and
semiconductors to magnetic insulators. However, the mechanism, the long-range
nature, of the SSE in metals is still to be clarified. Here we found that,
using a Ni81Fe19/Pt bilayer wire on an insulating sapphire plate, the
long-range spin voltage induced by the SSE in magnetic metals is due to
phonons. Under a temperature gradient in the sapphire, surprisingly, the
voltage generated in the Pt layer is shown to reflect the wire position,
although the wire is isolated both electrically and magnetically. This
non-local voltage is direct evidence that the SSE is attributed to the coupling
of spins and phonons. We demonstrate this coupling by directly injecting sound
waves, which realizes the acoustic spin pumping. Our finding opens the door to
""acoustic spintronics"" in which phonons are exploited for constructing
spin-based devices.",1103.6120v1
2011-08-08,"Spin-Orbital Locking, Emergent Pseudo-Spin, and Magnetic order in Honeycomb Lattice Iridates","The nature of the effective spin Hamiltonian and magnetic order in the
honeycomb iridates is explored by considering a trigonal crystal field effect
and spin-orbit coupling. Starting from a Hubbard model, an effective spin
Hamiltonian is derived in terms of an emergent pseudo-spin-1/2 moment in the
limit of large trigonal distortions and spin-orbit coupling. The present
pseudo-spins arise from a spin-orbital locking and are different from the jeff
= 1/2 moments that are obtained when the spin-orbit coupling dominates and
trigonal distortions are neglected. The resulting spin Hamiltonian is
anisotropic and frustrated by further neighbour interactions. Mean field theory
suggests a ground state with 4-sublattice zig-zag magnetic order in a parameter
regime that can be relevant to the honeycomb iridate compound Na2IrO3, where
similar magnetic ground state has recently been observed. Various properties of
the phase, the spin-wave spectrum and experimental consequences are discussed.
The present approach contrasts with the recent proposals to understand iridate
compounds starting from the strong spin-orbit coupling limit and neglecting
non-cubic lattice distortions.",1108.1806v3
2015-03-17,Successive magnetic transitions relating to itinerant spins and localized Cu spins in La2-xSrxCu1-yFeyO4: Possible existence of stripe correlations in the overdoped regime,"In order to investigate the relationship between the so-called stripe
correlations and the high-Tc superconductivity, we have carried out magnetic
susceptibility and zero-field muon-spin-relaxation measurements in partially
Fe-substituted La2-xSrxCu1-yFeyO4 (LSCFO). It has been found that the Fe
substitution induces successive magnetic transitions in the overdoped regime,
namely, a spin-glass transition of Fe3+ spins due to the RKKY interaction based
on itinerant spins at higher temperatures and a stripe-order transition of
localized Cu2+ spins at lower temperatures. The stripe-order transition
disappears at the hole concentration of ~0.28 per Cu which coincides with the
endpoint of the superconductivity in pristine La2-xSrxCuO4, suggesting that the
stripe correlations are closely related to the high-Tc superconductivity in the
overdoped regime as well as in the underdoped regime. As for the spin-glass
state, it has been found that the contribution of polarized itinerant spins to
the muon-spin depolarization is not negligible. Taking into account
neutron-scattering results by R.-H. He et al. [Phys. Rev. Lett. 107, 127002
(2011)] that a spin-density-wave (SDW) order has been observed in overdoped
LSCFO, the present results demonstrate the presence of a novel coexistent state
of a SDW order and a spin-glass state.",1503.04902v1
2015-07-25,Quantum entanglement in the one-dimensional spin-orbital SU(2)$\otimes XXZ$ model,"We investigate the phase diagram and the spin-orbital entanglement of a
one-dimensional SU(2)$\otimes XXZ$ model with SU(2) spin exchange and
anisotropic $XXZ$ orbital exchange interactions and negative exchange coupling.
As a unique feature, the spin-orbital entanglement entropy in the entangled
ground states increases here linearly with system size. In the case of Ising
orbital interactions we identify an emergent phase with long-range spin-singlet
dimer correlations triggered by a quadrupling of correlations in the orbital
sector. The peculiar translational invariant spin-singlet dimer phase has
finite von Neumann entanglement entropy and survives when orbital quantum
fluctuations are included. It even persists in the isotropic
SU(2)$\otimes$SU(2) limit. Surprisingly, for finite transverse orbital coupling
the long-range spin singlet correlations also coexist in the antiferromagnetic
spin and alternating orbital phase making this phase also unconventional.
Moreover we also find a complementary orbital singlet phase that exists in the
isotropic case but does not extend to the Ising limit. The nature of
entanglement appears essentially different from that found in the frequently
discussed model with positive coupling. Furthermore we investigate the
collective spin and orbital wave excitations of the disentangled
ferromagnetic-spin/ferro-orbital ground state and explore the continuum of
spin-orbital excitations. Interestingly one finds among the latter excitations
two modes of exciton bound states. Their spin-orbital correlations differ from
the remaining continuum states and exhibit logarithmic scaling of the von
Neumann entropy with increasing system size.",1507.07103v1
2016-02-25,Phase diagram and collective excitation in excitonic insulator: from the orbital physics viewpoint,"Excitonic insulating system is studied from the viewpoints of the orbital
physics in strongly correlated electron systems. An effective model Hamiltonian
for low-energy electronic states is derived from the two-orbital Hubbard model
with a finite energy difference corresponding to the crystalline field
splitting. The effective model is represented by the spin operators and the
pseudo-spin operators for the spin-state degrees of freedom. The ground state
phase diagram is analyzed by the mean-field approximation. In addition to the
low-spin state and high-spin state phases, two kinds of the excitonic
insulating phases emerge as a consequence of the competition between the
crystalline field effect and the Hund coupling. The excitonic transition is
classified to be an Ising-like transition reflecting a spontaneous breaking of
the $Z_2$ symmetry. Magnetic structures in the two excitonic insulating phases
are different from each other; an antiferromagnetic order and a spin nematic
order. Collective excitations in each phase are examined by using the
generalized spin-wave method. The Goldstone modes in the excitonic insulating
phases appear in the dynamical correlation functions for the spins and
pseudo-spin operators. Both the transverse and longitudinal spin excitation
modes are active in the two excitonic insulating phases in contrast to the
low-spin state and high-spin state phases. Connections of the present results
to the perovskite cobalt oxides are discussed.",1602.07831v2
2018-11-10,Spin-valley half-metal in systems with Fermi surface nesting,"Half-metals have fully spin polarized charge carriers at the Fermi surface.
Such polarization usually occurs due to strong electron--electron correlations.
Recently [Phys. Rev. Lett. {\bf{119}}, 107601 (2017)], we have demonstrated
theoretically that adding (or removing) electrons to systems with Fermi surface
nesting also stabilizes the half-metallic states even in the weak-coupling
regime. In the absence of doping, the ground state of the system is a spin or
charge density wave, formed by four nested bands. Each of these bands is
characterized by charge (electron/hole) and spin (up/down) labels. Only two of
these bands accumulate charge carriers introduced by doping, forming a
half-metallic two-valley Fermi surface. Analysis demonstrates that two types of
such half-metallicity can be stabilized. The first type corresponds to the full
spin polarization of the electrons and holes at the Fermi surface. The second
type, with antiparallel spins in electron-like and hole-like valleys, is
referred to as a ""spin-valley half-metal"" and corresponds to the complete
polarization with respect to the spin-valley operator. We analyze spin and
spin-valley currents and possible superconductivity in these systems. We show
that spin or spin-valley currents can flow in both half-metallic phases.",1811.04202v1
2020-03-05,The Evolution of Primordial Black Holes and their Final Observable Spins,"Primordial black holes in the mass range of ground-based gravitational-wave
detectors can comprise a significant fraction of the dark matter. Mass and spin
measurements from coalescences can be used to distinguish between an
astrophysical or a primordial origin of the binary black holes. In standard
scenarios the spin of primordial black holes is very small at formation.
However, the mass and spin can evolve through the cosmic history due to
accretion. We show that the mass and spin of primordial black holes are
correlated in a redshift-dependent fashion, in particular primordial black
holes with masses below ${\cal O}(30)M_\odot$ are likely non-spinning at any
redshift, whereas heavier black holes can be nearly extremal up to redshift
$z\sim10$. The dependence of the mass and spin distributions on the redshift
can be probed with future detectors such as the Einstein Telescope. The mass
and spin evolution affect the gravitational waveform parameters, in particular
the distribution of the final mass and spin of the merger remnant, and that of
the effective spin of the binary. We argue that, compared to the
astrophysical-formation scenario, a primordial origin of black hole binaries
might better explain the spin distribution of merger events detected by
LIGO-Virgo, in which the effective spin parameter of the binary is compatible
to zero except possibly for few high-mass events. Upcoming results from
LIGO-Virgo third observation run might reinforce or weaken these predictions.",2003.02778v2
2019-10-21,High-frequency magnon excitation due to femtosecond spin-transfer torques,"Femtosecond laser pulses can induce ultrafast demagnetization as well as
generate bursts of hot electron spin currents. In trilayer spin valves
consisting of two metallic ferromagnetic layers separated by a nonmagnetic one,
hot electron spin currents excited by an ultrashort laser pulse propagate from
the first ferromagnetic layer through the spacer reaching the second magnetic
layer. When the magnetizations of the two magnetic layers are noncollinear,
this spin current exerts a torque on magnetic moments in the second
ferromagnet. Since this torque is acting only within the sub-ps timescale, it
excites coherent high-frequency magnons as recently demonstrated in
experiments. Here, we calculate the temporal shape of the hot electron spin
currents using the superdiffusive transport model and simulate the response of
the magnetic system to the resulting ultrashort spin-transfer torque pulse by
means of atomistic spin-dynamics simulations. Our results confirm that the
acting spin-current pulse is short enough to excite magnons with frequencies
beyond 1 THz, a frequency range out of reach for current induced spin-transfer
torques. We demonstrate the formation of thickness dependent standing spin
waves during the first picoseconds after laser excitation. In addition, we vary
the penetration depth of the spin-transfer torque to reveal its influence on
the excited magnons. Our simulations clearly show a suppression effect of
magnons with short wavelengths already for penetration depths in the range of 1
nm confirming experimental findings reporting penetration depths below $2\,
{\rm nm}$.",1910.09412v1
2022-11-08,Spin effects in Spherical Harmonic Modes of Gravitational Waves from Eccentric Compact Binary Inspirals,"We compute the leading and sub-leading spin effects through the second
post-Newtonian order (2PN) in spherical harmonic modes of gravitational
waveforms from inspiralling compact binaries in non-circular orbits with
non-precessing components. The two spin couplings, linear-in-spin (spin-orbit;
SO) and quadratic-in-spin (spin-spin; SS), that appear in 2PN waveforms are
computed with desired accuracy and explicit expressions for relevant modes are
derived. The modes that have spin corrections through 2PN include $(\ell,
|m|)$=$((2,2),\,(2,1),\,(3,3),\,(3,2),\,(3,1),\,(4,3),\,(4,1))$ modes. Closed
form expressions for these modes for compact binaries in general orbits as well
as in elliptical orbits are being provided. While the general orbit results can
be used to study signals from binaries in orbits of arbitrary shape and nature,
elliptical orbit results are applicable to systems with arbitrary
eccentricities. We also express the elliptical orbit results as leading
eccentric corrections to the circular results. Our prescription represents, the
first, fully analytical treatment that combines spins, eccentricity and higher
modes together and completes computation of spin effects through 2PN order.
These should find immediate applications in inspiral-merger-ringdown modelling
for eccentric mergers including the effect of non-precessing spins and higher
modes as well as in parameter estimation analyses employing inspiral waveform.",2211.04155v2
2023-02-14,Collapsar Gamma-ray Bursts Grind their Black Hole Spins to a Halt,"The spin of a newly formed black hole (BH) at the center of a massive star
evolves from its natal value due to two competing processes: accretion of gas
angular momentum that increases the spin, and extraction of BH angular momentum
by outflows that decreases the spin. Ultimately, the final, equilibrium spin is
set by the balance between both processes. In order for the BH to launch
relativistic jets and power a $ \gamma $-ray burst (GRB), the BH magnetic field
needs to be dynamically important. Thus, we consider the case of a magnetically
arrested disk (MAD) driving the spin evolution of the BH. By applying the
semi-analytic MAD BH spin evolution model of Lowell et al. (2023) to
collapsars, we show that if the BH accretes $ \sim 20\% $ of its initial mass,
its dimensionless spin inevitably reaches small values, $ a \lesssim 0.2 $. For
such spins, and for mass accretion rates inferred from collapsar simulations,
we show that our semi-analytic model reproduces the energetics of typical GRB
jets, $L_{\rm jet}\sim10^{50}\,\,{\rm erg\,s^{-1}}$. We show that our
semi-analytic model reproduces the nearly constant power of typical GRB jets.
If the MAD onset is delayed, this allows powerful jets at the high end of the
GRB luminosity distribution, $L_{\rm jet}\sim10^{52}\,\,{\rm erg\,s^{-1}}$, but
the final spin remains low, $ a \lesssim 0.3 $. These results are consistent
with the low spins inferred from gravitational wave detections of binary BH
mergers. In a companion paper, Gottlieb et al. (2023), we use GRB observations
to constrain the natal BH spin to be $ a \simeq 0.2 $.",2302.07281v1
2023-02-22,Quantum sensing and imaging with spin defects in hexagonal boron nitride,"Color centers in hexagonal boron nitride (hBN) have recently emerged as
promising candidates for a new wave of quantum applications. Thanks to hBN's
high stability and 2-dimensional (2D) layered structure, color centers in hBN
can serve as robust quantum emitters that can be readily integrated into
nanophotonic and plasmonic structures on a chip. More importantly, the recently
discovered optically addressable spin defects in hBN provide a quantum
interface between photons and electron spins for quantum sensing applications.
The most well-studied hBN spin defects, the negatively charged boron vacancy
($V_B^-$) spin defects, have been used for quantum sensing of static magnetic
fields, magnetic noise, temperature, strain, nuclear spins, paramagnetic spins
in liquids, RF signals, and beyond. In particular, hBN nanosheets with spin
defects can form van der Waals (vdW) heterostructures with 2D magnetic or other
materials for in situ quantum sensing and imaging. This review summarizes the
rapidly evolving field of nanoscale and microscale quantum sensing with spin
defects in hBN. We introduce basic properties of hBN spin defects, quantum
sensing protocols, and recent experimental demonstrations of quantum sensing
and imaging with hBN spin defects. We also discuss methods to enhance their
sensitivity. Finally, we envision some potential developments and applications
of hBN spin defects.",2302.11169v2
2023-08-02,Constraining the nature of dark compact objects with spin-induced octupole moment measurement,"Various theoretical models predict the existence of exotic compact objects
that can mimic the properties of black holes (BHs). Gravitational waves (GWs)
from the mergers of compact objects have the potential to distinguish between
exotic compact objects and BHs. The measurement of spin-induced multipole
moments of compact objects in binaries provides a unique way to test the nature
of compact objects. The observations of GWs by LIGO and Virgo have already put
constraints on the spin-induced quadrupole moment, the leading order
spin-induced moment. In this work, we develop a Bayesian framework to measure
the spin-induced octupole moment, the next-to-leading order spin-induced
moment. The precise measurement of the spin-induced octupole moment will allow
us to test its consistency with that of Kerr BHs in general relativity and
constrain the allowed parameter space for non-BH compact objects. For various
simulated compact object binaries, we explore the ability of the LIGO and Virgo
detector network to constrain the spin-induced octupole moment of compact
objects. We find that LIGO and Virgo at design sensitivity can constrain the
symmetric combination of component spin-induced octupole moments of binary for
dimensionless spin magnitudes $\sim 0.8$. Further, we study the possibility of
simultaneously measuring the spin-induced quadrupole and octupole moments.
Finally, we perform this test on selected GW events reported in the third GW
catalog. These are the first constraints on spin-induced octupole moment using
full Bayesian analysis.",2308.01309v2
2023-11-20,Ground state of the $S$=1/2 pyrochlore Heisenberg antiferromagnet: A quantum spin liquid emergent from dimensional reduction,"The quantum antiferromagnet on the pyrochlore lattice offers an archetypal
frustrated system, which potentially realizes a quantum spin liquid
characterized by the absence of standard spontaneous symmetry breaking even at
zero temperature, unusually as an isotropic 3D system. Despite tremendous
progress in the literature, however, the nature of the ground state of the
fully quantum-mechanical spin Hamiltonian on the pyrochlore lattice still
remains elusive. Here, we show that an unconventional type of quantum spin
liquid is born out from the pyrochlore system after the self-organized
dimensional reduction leading to confined states in 2D layers. This conclusion
is obtained from state-of-the-art variational Monte Carlo (VMC) simulations at
zero temperature. Quantum spin liquids triggered by the emergent dimensional
reduction is an unexplored route of the spin-liquid formation. The dimensional
reduction from 3D to 2D is a consequence of a conventional spontaneous symmetry
breaking, while the resultant decoupling of layers enables the emergence of a
2D quantum spin liquid that is adiabatically disconnected from trivial product
states and exhibits strong quantum entanglement. The stabilized quantum spin
liquid exhibits an algebraic decay of correlations and vanishing excitation gap
in the thermodynamic limit. The wave-function structure supports the
fractionalization of the spin into spinons. This spin-liquid ground state
persists in the presence of spin-orbit interactions, which expands the
possibilities of realizing quantum spin liquids in real pyrochlore-structured
materials.",2311.11561v1
2005-05-16,Spin-Dependent Cyclotron Decay Rates in Strong Magnetic Fields,"Cyclotron decay and absorption rates have been well studied in the
literature, focusing primarily on spectral, angular and polarization
dependence. Astrophysical applications usually do not require retention of
information on the electron spin state, and these are normally averaged in
obtaining the requisite rates. In magnetic fields, higher order quantum
processes such as Compton scattering become resonant at the cyclotron frequency
and its harmonics, with the resonances being formally divergent. Such
divergences are usually eliminated by accounting for the finite lifetimes of
excited Landau states. This practice requires the use of spin-dependent
cyclotron rates in order to obtain accurate determinations of process rates
very near cyclotronic resonances, the phase space domain most relevant for
certain applications to pulsar models. This paper develops previous results in
the literature to obtain compact analytic expressions for cyclotron decay
rates/widths in terms of a series of Legendre functions of the second kind;
these expressions can be expediently used in astrophysical models. The rates
are derived using two popular eigenstate formalisms, namely that due to Sokolov
and Ternov, and that due to Johnson and Lippmann. These constitute two sets of
eigenfunctions of the Dirac equation that diagonalize different operators, and
accordingly yield different spin-dependent cyclotron rates. This paper
illustrates the attractive Lorentz transformation characteristics of the
Sokolov and Ternov formulation, which is another reason why it is preferable
when electron spin information must be explicitly retained.",0505327v1
2007-06-27,Kondo quantum dot coupled to ferromagnetic leads: Numerical renormalization group study,"We systematically study the influence of ferromagnetic leads on the Kondo
resonance in a quantum dot tuned to the local moment regime. We employ Wilson's
numerical renormalization group method, extended to handle leads with a spin
asymmetric density of states, to identify the effects of (i) a finite spin
polarization in the leads (at the Fermi-surface), (ii) a Stoner splitting in
the bands (governed by the band edges) and (iii) an arbitrary shape of the
leads density of states. For a generic lead density of states the quantum dot
favors being occupied by a particular spin-species due to exchange interaction
with ferromagnetic leads leading to a suppression and splitting of the Kondo
resonance. The application of a magnetic field can compensate this asymmetry
restoring the Kondo effect. We study both the gate-voltage dependence (for a
fixed band structure in the leads) and the spin polarization dependence (for
fixed gate voltage) of this compensation field for various types of bands.
Interestingly, we find that the full recovery of the Kondo resonance of a
quantum dot in presence of leads with an energy dependent density of states is
not only possible by an appropriately tuned external magnetic field but also
via an appropriately tuned gate voltage. For flat bands simple formulas for the
splitting of the local level as a function of the spin polarization and gate
voltage are given.",0706.3997v1
2013-01-17,"63,65Cu Nuclear Resonance Study of the Coupled Spin Dimers and Chains Compound Cu2Fe2Ge4O13","Nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) of Cu
have been measured in a coupled spin dimers and chains compound Cu2Fe2Ge4O13.
Cu NQR has also been measured in an isostructural material Cu2Sc2Ge4O13
including only spin dimers. Comparison of the temperature dependence of the
63Cu nuclear spin-lattice relaxation rate between the two compounds reveals
that the Fe chains in Cu2Fe2Ge4O13 do not change a spin gap energy of the Cu
dimers from that in Cu2Sc2Ge4O13, contributing additionally to the relaxation
rate at the Cu site. A modestly large internal field of 3.39 T was observed at
the Cu site in the antiferromagnetic state of Cu2Fe2Ge4O13 at 4.2 K, which is
partly because of quantum reduction of the ordered moment of a Cu atom. The
internal field and the ordered moment of Cu are noncollinear due to large
anisotropy of the hyperfine interaction at the Cu site. A model analysis of the
internal field based on the fourfold planar coordination of Cu suggests that a
3d hole of the Cu2+ ion is mainly in the d(x2-y2) orbital state.",1301.3974v2
2013-02-01,$Ξ$ baryon strong decays in a chiral quark model,"The strong decays of $\Xi$ baryons up to N=2 shell were studied in a chiral
quark model. The strong decay properties of these well-established ground
decuplet baryons were reasonably described. We found that (i) $\Xi(1690)$ and
$\Xi(1820)$ could be assigned to the spin-parity $J^P=1/2^-$ state
$|70,^{2}{8},1,1,1/2^->$ and the spin-parity $J^P=3/2^-$ state
$|70,^{2}{8},1,1,3/2^->$, respectively. Slight configuration mixing might exist
in these two negative parity states. (ii) $\Xi(1950)$ might correspond to
several different $\Xi$ resonances. The broad states ($\Gamma\sim 100$ MeV)
observed in the $\Xi\pi$ channel could be classified as the pure $J^P=5/2^-$
octet state $\Xi^0|70,^{4}8,1,1,5/2^->$ or the mixed state $|\Xi 1/2^->_3 $
with $J^P=1/2^-$. The $\Xi$ resonances with moderate width ($\Gamma\sim 60$
MeV) observed in the $\Xi\pi$ channel might correspond to the $J^P=1/2^+$
excitation $|56,^{4}10,2,2,1/2^+>$. The second orbital excitation
$|56,^{4}10,2,2,3/2^+>$ and the mixed state $|\Xi 1/2^->_1$ might be candidates
for the narrow width state observed in the $\Lambda \bar{K}$ channel, however,
their spin-parity numbers are incompatible with the moment analysis of the
data. (iii) $\Xi(2030)$ could not be assigned to either any spin-parity
$J^P=7/2^+$ states or any pure $J^P=5/2^+$ configurations. It seems to favor
the $|70,^{2}8,2,2,3/2^+>$ assignment, however, its spin conflicts with the
moment analysis of the data. To find more $\Xi$ resonances, the observations in
the $\Xi(1530)\pi$ and $\Sigma(1385) \bar{K}$ channels are necessary.",1302.0079v2
2014-07-23,Preferential antiferromagnetic coupling of vacancies in graphene on SiO_2: Electron spin resonance and scanning tunneling spectroscopy,"Monolayer graphene grown by chemical vapor deposition and transferred to
SiO_2 is used to introduce vacancies by Ar^+ ion bombardment at a kinetic
energy of 50 eV. The density of defects visible in scanning tunneling
microscopy (STM) is considerably lower than the ion fluence implying that most
of the defects are single vacancies. The vacancies are characterized by
scanning tunneling spectroscopy (STS) on graphene and HOPG exhibiting a peak
close to the Fermi level. The peak persists after air exposure up to 180 min,
albeit getting broader. After air exposure for less than 60 min, electron spin
resonance (ESR) at 9.6 GHz is performed. For an ion flux of 10/nm^2, we find a
signal corresponding to a g-factor of 2.001-2.003 and a spin density of 1-2
spins/nm^2. The ESR signal consists of a mixture of a Gaussian and a Lorentzian
of equal weight exhibiting a width down to 0.17 mT, which, however, depends on
details of the sample preparation. The g-factor anisotropy is about 0.02%.
Temperature dependent measurements reveal antiferromagnetic correlations with a
Curie-Weiss temperature of -10 K. Albeit the electrical conductivity of
graphene is significantly reduced by ion bombardment, the spin resonance
induced change in conductivity is below 10^{-5}.",1407.6280v2
2016-06-24,The Spin-Orbit Evolution of GJ 667C System: The Effect of Composition and Other Planet's Perturbations,"Potentially habitable planets within the habitable zone of M-dwarfs are
affected by tidal interaction. We studied the tidal evolution in GJ 667C using
a numerical code we call TIDEV. We reviewed the problem of the dynamical
evolution focusing on the effects that a rheological treatment, different
compositions and the inclusion of orbital perturbations, have on the spin-down
time and the probability to be trapped in a low spin-orbit resonance.
Composition have a strong effect on the spin-down time, changing, in some
cases, by almost a factor of 2 with respect to the value estimated for a
reference Earth-like model. We calculated the time to reach a low resonance
value (3:2) for the configuration of 6 planets. Capture probabilities are
affected when assuming different compositions and eccentricities variations. We
chose planets b and c to evaluate the probabilities of capture in resonances
below 5:2 for two compositions: Earth-like and Waterworld planets. We found
that perturbations, although having a secular effect on eccentricities, have a
low impact on capture probabilities and noth- ing on spin-down times. The
implications of the eccentricity variations and actual habitability of the GJ
667C system are discussed.",1606.07546v2
2017-07-13,Feedback control optimisation of ESR experiments,"Numerically optimised microwave pulses are used to increase excitation
efficiency and modulation depth in electron spin resonance experiments
performed on a spectrometer equipped with an arbitrary waveform generator. The
optimisation procedure is sample-specific and reminiscent of the magnet
shimming process used in the early days of nuclear magnetic resonance -- an
objective function (for example, echo integral in a spin echo experiment) is
defined and optimised numerically as a function of the pulse waveform vector
using noise-resilient gradient-free methods. We found that the resulting shaped
microwave pulses achieve higher excitation bandwidth and better echo modulation
depth than the pulse shapes used as the initial guess. Although the method is
theoretically less sophisticated than simulation based quantum optimal control
techniques, it has the advantage of being free of the linear response
approximation; rapid electron spin relaxation also means that the optimisation
takes only a few seconds. This makes the procedure fast, convenient, and easy
to use. An important application of this method is at the final stage of the
implementation of theoretically designed pulse shapes: compensation of pulse
distortions introduced by the instrument. The performance is illustrated using
spin echo and out-of-phase electron spin echo envelope modulation experiments.
Interface code between Bruker SpinJet arbitrary waveform generator and Matlab
is included in versions 2.2 and later of the Spinach library.",1707.05184v3
2017-08-14,Super-spinning compact objects and models of high-frequency quasi-periodic oscillations observed in Galactic microquasars. II. Forced resonances,"In our previous work (Paper I) we applied several models of high-frequency
quasi-periodic oscillations (HF QPOs) to estimate the spin of the central
compact object in three Galactic microquasars assuming the possibility that the
central compact body is a super-spinning object (or a naked singularity) with
external spacetime described by Kerr geometry with a dimensionless spin
parameter $a\equiv cJ/GM^2>1$. Here we extend our consideration, and in a
consistent way investigate implications of a set of ten resonance models so far
discussed only in the context of $a<1$. The same physical arguments as in Paper
I are applied to these models, i.e. only a small deviation of the spin estimate
from $a=1$, $a\gtrsim 1$, is assumed for a favoured model. For five of these
models that involve Keplerian and radial epicyclic oscillations we find the
existence of a unique specific QPO excitation radius. Consequently, there is a
simple behaviour of dimensionless frequency $M\times\nu_{U}(a)$ represented by
a single continuous function having solely one maximum close to $a\gtrsim1$.
Only one of these models is compatible with the expectation of $a\gtrsim 1$.
The other five models that involve the radial and vertical epicyclic
oscillations imply the existence of multiple resonant radii. This signifies a
more complicated behaviour of $M\times\nu_{U}(a)$ that cannot be represented by
single functions. Each of these five models is compatible with the expectation
of $a\gtrsim 1$.",1708.04300v1
2018-12-09,Spin squeezing via one- and two-axis twisting induced by a single off-resonance stimulated Raman scattering in a cavity,"Squeezed spin states have important applications in quantum metrology and
sensing. It has been shown by S{\o}rensen and M{\o}lmer [Phys. Rev. A 66,
022314(2002)] that an effective one-axis-twisting interaction can be realized
in a cavity setup via a double off-resonance stimulated Raman scattering,
resulting in a noise reduction scaling $\propto 1/N^{2/3}$ with $N$ being the
atom number. Here, we show that, by making an appropriate change of the initial
input spin state, it is possible to produce a one-axis-twisting spin squeezing
via a \emph{single} off-resonance stimulated Raman scattering, which thus can
greatly simplify the realistic implementation. We also show that the
one-axis-twisting interaction can be transformed into a more efficient
two-axis-twisting interaction by rotating the collective spin while coupling to
the cavity, yielding a Heisenberg limited noise reduction $\propto1/N$.
Considering the noise effects due to atomic decoherence and cavity decay, we
find that substantial squeezing is still attainable with current laboratory
techniques.",1812.03463v2
2016-03-09,Suppression of spin-exciton state in hole overdoped iron-based superconductors,"The mechanism of Cooper pair formation in iron-based superconductors remains
a controversial topic. The main question is whether spin or orbital
fluctuations are responsible for the pairing mechanism. To solve this problem,
a crucial clue can be obtained by examining the remarkable enhancement of
magnetic neutron scattering signals appearing in a superconducting phase. The
enhancement is called spin resonance for a spin fluctuation model, in which
their energy is restricted below twice the superconducting gap value (2Ds),
whereas larger energies are possible in other models such as an orbital
fluctuation model. Here we report the doping dependence of low-energy magnetic
excitation spectra in Ba1-xKxFe2As2 for 0.5<x<0.84 studied by inelastic neutron
scattering. We find that the behavior of the spin resonance dramatically
changes from optimum to overdoped regions. Strong resonance peaks are observed
clearly below 2Ds in the optimum doping region, while they are absent in the
overdoped region. Instead, there is a transfer of spectral weight from energies
below 2Ds to higher energies, peaking at values of 3Ds for x = 0.84. These
results suggest a reduced impact of magnetism on Cooper pair formation in the
overdoped region.",1603.02762v1
2017-04-05,Influence of the nuclear Zeeman effect on mode locking in pulsed semiconductor quantum dots,"The coherence of the electron spin in a semiconductor quantum dot is strongly
enhanced by mode locking through nuclear focusing, where the synchronization of
the electron spin to periodic pulsing is slowly transferred to the nuclear
spins of the semiconductor material, mediated by the hyperfine interaction
between these. The external magnetic field that drives the Larmor oscillations
of the electron spin also subjects the nuclear spins to a Zeeman-like coupling,
albeit a much weaker one. For typical magnetic fields used in experiments, the
energy scale of the nuclear Zeeman effect is comparable to that of the
hyperfine interaction, so that it is not negligible. In this work, we analyze
the influence of the nuclear Zeeman effect on mode locking quantitatively.
Within a perturbative framework, we calculate the Overhauser-field distribution
after a prolonged period of pulsing. We find that the nuclear Zeeman effect can
exchange resonant and non-resonant frequencies. We distinguish between models
with a single type and with multiple types of nuclei. For the latter case, the
positions of the resonances depend on the individual $g$ factors, rather than
on the average value.",1704.01468v2
2020-12-18,Single-electron spin resonance in a nanoelectronic device using a global field,"Spin-based silicon quantum electronic circuits offer a scalable platform for
quantum computation, combining the manufacturability of semiconductor devices
with the long coherence times afforded by spins in silicon. Advancing from
current few-qubit devices to silicon quantum processors with upwards of a
million qubits, as required for fault-tolerant operation, presents several
unique challenges, one of the most demanding being the ability to deliver
microwave signals for large-scale qubit control. Here we demonstrate a
potential solution to this problem by using a three-dimensional dielectric
resonator to broadcast a global microwave signal across a quantum
nanoelectronic circuit. Critically, this technique utilizes only a single
microwave source and is capable of delivering control signals to millions of
qubits simultaneously. We show that the global field can be used to perform
spin resonance of single electrons confined in a silicon double quantum dot
device, establishing the feasibility of this approach for scalable spin qubit
control.",2012.10225v3
2022-01-19,Supercurrent in the presence of direct transmission and a resonant localized state,"Inspired by recent experimental findings that will be presented elsewhere, we
formulate and investigate a model of a superconducting junction that combines
the electron propagation in a quantum channel with an arbitrary transmission,
and that through a localized state. Interesting situation occurs if the energy
of the localized state is close to Fermi level, that is, the state is in
resonant tunnelling regime. Since this energy is affected by the gate voltage,
we expect a drastic modification of transport properties of the junction in a
narrow interval of the gate voltages where the energy distance to Fermi level
is of the order of $\Gamma, \Delta$, $\Gamma$ being the energy broadening of
the localized state, $\Delta$ being the superconducting energy gap.
  We consider the model neglecting the interaction in the localized state, as
well as accounting for the interaction in a simplistic mean-field approach
where it manifests itself as a spin-splitting. This spin splitting is also
contributed by external magnetic field. We also take into account the
spin-orbit interaction that can be significant in realistic experimental
circumstances.
  In normal state, we find that the model may describe both peak and dip in the
transmission at resonant gate voltage. Spin splitting splits the positions of
these peculiarities. Fano interference of the transmission amplitudes results
in an asymmetric shape of the peaks/dips. In superconducting state, the spin
splitting results in a complex dependence of the superconducting current on the
superconducting phase. In several cases, this is manifested as a pair of $0 -
\pi$ transitions in the narrow interval of gate voltages.
  The article in the present form is not intended for a journal submission.",2201.07848v1
2022-07-24,Tilting Uranus via Secular Spin-Orbit Resonance with Planet 9,"Uranus' startlingly large obliquity of 98 degrees has yet to admit a
satisfactory explanation. The most widely accepted hypothesis involving a giant
impactor that tipped Uranus onto its side encounters several difficulties with
regards to the Uranus' spin rate and its prograde satellite system. An
obliquity increase that was driven by capture of Uranus into a secular
spin-orbit resonance remains a possible alternative hypothesis that avoids many
of the issues associated with a giant impact. We propose that secular
spin-orbit resonance could have excited Uranus' obliquity to its present day
value if it was driven by the outward migration of an as-yet undetected outer
Solar System body commonly known as Planet Nine. We draw support for our
hypothesis from an analysis of 123 N-body simulations with varying parameters
for Planet Nine and its migration. We find that in multiple instances, a
simulated Planet Nine drives Uranus' obliquity past 98 degrees, with a
significant number falling within 10 percent of this value. We note a
significant caveat to our results in that a much faster than present-day
spin-axis precession rate for Uranus is required in all cases for it to reach
high obliquities. We conclude that while it was in principle possible for
Planet Nine (if it exists) to have been responsible for Uranus' obliquity, the
feasibility of such a result hinges on Uranus' primordial precession rate.",2207.11823v1
2022-07-31,Possible coexistence of short-range resonating-valence-bond and long-range stripe correlations in the spatially anisotropic triangular-lattice quantum magnet Cu$_2$(OH)$_3$NO$_3$,"We show that short-range resonating-valence-bond correlations and long-range
order can coexist in the ground state (GS) of a frustrated spin system. Our
study comprises a comprehensive investigation of the quantum magnetism on the
structurally disorder-free single crystal of Cu$_2$(OH)$_3$NO$_3$, which
realizes the $s$ = 1/2 Heisenberg model on a spatially anisotropic triangular
lattice. Competing exchange interactions determined by fitting the
magnetization measured up to 55 T give rise to an exotic GS wavefunction with
coexistence of the dominant short-range resonating-valence-bond correlations
and weak long-range stripe order (ordered moment $M_0$ = $|\langle
s_i^z\rangle|$ $\sim$ 0.02). At low temperatures, a first-order spin-flop
transition is visible at $\sim$ 1-3 T. As the applied field further increases,
another two magnetic-field-induced quantum phase transitions are observed at
$\sim$ 14-19 and $\sim$ 46-52 T, respectively. Simulations of the Heisenberg
exchange model show semi-quantitative agreement with the magnetic-field
modulation of these unconventional phases, as well as the absence of visible
magnetic reflections in neutron diffraction, thus supporting the GS of the spin
system of Cu$_2$(OH)$_3$NO$_3$ may be approximate to a quantum spin liquid. Our
study establishes structurally disorder-free magnetic materials with spatially
anisotropic exchange interactions as a possible arena for spin liquids.",2208.00382v1
2023-10-02,Evolution of Stellar Bars in Spinning Dark Matter Halos and Stellar Bulges,"We use high-resolution numerical simulations to follow the barred disk
evolution in a suite of models with progressively more massive stellar bulges,
with bulge-to-total (disk$+$bulge) mass ratios of $B/T\sim 0-0.25$, embedded in
dark matter (DM) halos with the spin $\lambda \sim 0 - 0.09$. We focus on
models with a sequence of initial rotational support for bulges, and analyze
their spinup and spindown. We find that (1) the presence of a bulge affects the
evolution of stellar bars, i.e., the timescale of bar instability, bar pattern
speed and its decay, and the vertical buckling instability. The bar strength is
nearly independent of $B/T$ in halos with spin $\lambda = 0$, and is suppressed
by a factor $\sim 2$ for halos with $\lambda = 0.09$; (2) The main effect of
the bulge is the destruction of the harmonic core which affects the buckling;
(3) The bulge plays a minor role in the exchange of angular momentum between
the barred disk and the DM halo, during its spinup and spindown; (4) Most
interestingly, the buckling process triggers different response above/below the
disk midplane, which anti-correlates with the bulge mass; (5) In spinning
halos, the buckling process has a prolonged amplitude tail, extending by few
Gyr, as verified by measuring distortions in the Laplace plane; (6)
Furthermore, as verified by orbital spectral analysis, the bulge gains its spin
from the bar mainly via the inner Lindblad resonance, while losing it via a
number of resonances lying between the outer and inner Lindblad resonance.",2310.01411v1
2023-10-19,Resonant TERS of a Single-Molecule Kondo System,"Single-molecule tip-enhanced Raman spectroscopy (TERS) under ultra-high
vacuum (UHV) and cryogenic conditions enables exploration of the relations
between the adsorption geometry, electronic state, and vibrational fingerprints
of individual molecules. TERS capability of reflecting spin states in
open-shell molecular configurations is yet unexplored. Here we use the tip of a
scanning probe microscope to lift a perylene-3,4,9,10-tetracarboxylic
dianhydride (PTCDA) molecule from a metal surface to bring it into an
open-shell spin one-half anionic state. We reveal a correlation between the
appearance of a Kondo resonance in the differential conductance spectroscopy
and concurrent characteristic changes captured by the TERS measurements.
Through a detailed investigation of various adsorbed and tip-contacted PTCDA
scenarios, we infer that the Raman scattering on the suspended PTCDA is
resonant with a higher excited state. Theoretical simulation of the vibrational
spectra enables a precise assignment of the individual TERS peaks to
high-symmetry Ag modes, including the fingerprints of the observed spin state.
These findings highlight the potential of TERS in capturing complex
interactions between charge, spin, and photophysical properties in nanoscale
molecular systems, and suggest a pathway for designing spin-optical devices
using organic molecules.",2310.12546v1
2011-01-19,Spectral properties of cylindrical quasi-optical cavity resonator with random-inhomogeneous side boundary: correlation between dephasing and dissipation,"A rigorous solution for the spectrum of quasioptical cylindrical cavity
resonator with a randomly rough side boundary has been obtained for the first
time. To accomplish this task, we have developed a novel method for variables
separation in wave equation, which enables one, in principle, to rigorously
examine any limiting case --- from negligibly weak to arbitrarily strong
disorder. It is shown that the effect of disorder-induced scattering can be
properly described in terms of two geometric potentials, specifically, the
""amplitude"" and the ""gradient"" potentials, which appear in wave equation in the
course of conformal smoothing of the resonator boundaries. The scattering
resulting from the gradient potential appears to be dominant, and its impact on
the whole spectrum is governed by the unique sharpness parameter $\Xi$, the
mean tangent of the asperity slope. As opposed to the resonator with bulk
disorder, the distribution of nearest-neighbor spacings (NNS) in the
rough-resonator spectrum acquires Wigner-like features only when the wave
operator loses its unitarity, i.e., with the availability in the system of
either openness or dissipation channels. Our numeric experiments suggest that
in the absence of dissipation loss the random-rough resonator spectrum is
always regular, whatever the degree of roughness. Yet, the spectrum structure
is quite different in the domains of small and large values of the parameter
$\Xi$. For the dissipation-free resonator, the NNS distribution changes its
form with growing the asperity sharpness from Poissonian-like distribution in
the limit of $\Xi<<1$ to the bell-shaped distribution in the domain where
$\Xi>>1$.",1101.3743v2
2011-06-19,Oscillatory Energy Exchange Between Waves Coupled by a Dynamic Artificial Crystal,"We describe a general mechanism of controllable energy exchange between waves
propagating in a dynamic artificial crystal. We show that if a spatial
periodicity is temporarily imposed on the transmission properties of a
wave-carrying medium whilst a wave is inside, this wave is coupled to a
secondary counter-propagating wave and energy oscillates between the two. The
oscillation frequency is determined by the width of the spectral band gap
created by the periodicity and the frequency difference between the coupled
waves. The effect is demonstrated with spin waves in a dynamic magnonic
crystal.",1106.3722v1
2017-03-07,Partial waves in $B_s^* \bar B_s^*$ production in $e^+e^-$ annihilation near threshold,"The production of the vector meson pairs $B_s^* \bar B_s^*$ in the $e^+e^-$
annihilation is generally contributed by two $P$ wave amplitudes with different
total spin $S$ of the mesons, $S=0$ and $S=2$, and also by an $F$ wave
amplitude. Belle has recently reported a study of the available data at the
energy of the $\Upsilon(5S)$ peak in terms of the two $P$ wave contributions
only. It is argued here that although at this energy the $F$ wave should be
quite suppressed, especially for the strange-bottom vector mesons, the
particular studied angular distribution is very sensitive to a presence of even
small $F$ wave amplitude due to a significant interference with the dominant
$S=2$ $P$ wave. Thus the available data are not conclusive with regards to the
partial wave structure of the production amplitude. Additional angular
correlations are discussed that can be measured for a full amplitude analysis
of the production process.",1703.02524v1
2003-06-19,Theory of the Mercury's spin-orbit motion and analysis of its main librations,"The upcoming space missions, MESSENGER and BepiColombo with onboard
instrumentation capable of measuring the rotational parameters stimulate the
objective to reach an accurate theory of the rotational motion of Mercury. For
obtaining the real motion of Mercury, we have used our relativistic BJV model
of solar system integration including the coupled spin-orbit motion of the
Moon. We have extended this model by generalizing the spin-orbit couplings to
the terrestrial planets, notably Mercury. The updated model is called SONYR
(acronym of Spin-Orbit N-BodY Relativistic model). The SONYR model giving an
accurate solution of the spin-orbit motion of Mercury permits to analyze the
different families of the Hermean rotational librations. The spin-orbit motion
of Mercury is characterized by two proper frequencies (namely 15.847 and 1066
years) and its 3:2 resonance presents a second synchronism which can be
understood as a spin-orbit secular resonance (278 898 years). By using the
SONYR model, we find a new determination of the mean obliquity, namely 1.6
arcminutes. Besides, we identify in the Hermean librations the impact of the
uncertainty of the greatest principal moment of inertia (\cmr2) on the
obliquity and on the libration in longitude (2.3 mas and 0.45 as respectively
for an increase of 1% on the \cmr2 value). These determinations prove to be
suitable for providing constraints on the internal structure of Mercury.",0306387v2
2004-02-13,Probing spin and orbital Kondo effects with a mesoscopic interferometer,"We investigate theoretically the transport properties of a closed
Aharonov-Bohm interferometer containing two quantum dots in the strong coupling
regime. We find two distinct physical scenarios depending on the strength of
the interdot Coulomb interaction. When the interdot Coulomb interaction is
negligible only spin fluctuations are important and each dot develops a Kondo
resonance at the Fermi level independently of the applied magnetic flux. The
transport is characterized by the interference of these two independent Kondo
resonances. On the contrary, for large interdot interaction, only one electron
can be accommodated onto the double dot system. In this situation, not only the
spin can fluctuate but also the orbital degree of freedom (the pseudo-spin). As
a result, we find different ground states depending on the value of the applied
flux. When $\phi=\pi$ (mod $2\pi$) ($\phi=2\pi\Phi/\Phi_0$, where $\Phi$ is
applied flux, and $\Phi_0=h/e$ the flux quantum) the electronic transport can
take place via simultaneous correlations in the spin and pseudo-spin sectors,
leading to the highly symmetric SU(4) Kondo state. Nevertheless, we find
situations with $\phi>0$ (mod $2\pi$) where the pseudo-spin quantum number is
not conserved during tunneling events, giving rise to the common SU(2) Kondo
state with an enhanced Kondo temperature. We investigate the crossover between
both ground states and discuss possible experimental signatures of this physics
as a function of the applied magnetic flux.",0402361v2
2011-06-15,Non-Zeeman splitting for a spin-resolved STM with a Kondo adatom in a spin-polarized two-dimensional electron gas,"We theoretically investigate the spin-resolved local density of states
(SR-LDOS) of a spin-polarized two-dimensional electron gas in the presence of a
Kondo adatom and a STM probe. Using Green function formalism and the atomic
approach in the limit of infinite Coulomb correlation, it is found an
analytical SR-LDOS expression in the low temperature regime of the system. This
formal result is given in terms of phase shifts originated by the adatom
scattering and Fano interference. The SR-LDOS is investigated as a function of
the probe position and different Fano factors. Our findings provide an
alternative way to spin-split the Kondo resonance without the use of huge
magnetic fields, typically necessary in adatom systems characterized by large
Kondo temperatures. We observe a non-Zeeman spin-splitting of the Kondo
resonance in the total LDOS, with one spin-component pinned around the host
Fermi level. Interestingly, this result is in accordance to recent experimental
data reported in Phys. Rev. B 82, 020406(R) (2010).",1106.2853v5
2011-10-24,Enhancement of the Electron Spin Resonance of Single-Walled Carbon Nanotubes by Oxygen Removal,"We have observed a nearly fourfold increase in the electron spin resonance
(ESR) signal from an ensemble of single-walled carbon nanotubes (SWCNTs) due to
oxygen desorption. By performing temperature-dependent ESR spectroscopy both
before and after thermal annealing, we found that the ESR in SWCNTs can be
reversibly altered via the molecular oxygen content in the samples. Independent
of the presence of adsorbed oxygen, a Curie-law (spin susceptibility $\propto
1/T$) is seen from $\sim$4 K to 300 K, indicating that the probed spins are
finite-level species. For both the pre-annealed and post-annealed sample
conditions, the ESR linewidth decreased as the temperature was increased, a
phenomenon we identify as motional narrowing. From the temperature dependence
of the linewidth, we extracted an estimate of the intertube hopping frequency;
for both sample conditions, we found this hopping frequency to be $\sim$100
GHz. Since the spin hopping frequency changes only slightly when oxygen is
desorbed, we conclude that only the spin susceptibility, not spin transport, is
affected by the presence of physisorbed molecular oxygen in SWCNT ensembles.
Surprisingly, no linewidth change is observed when the amount of oxygen in the
SWCNT sample is altered, contrary to other carbonaceous systems and certain 1D
conducting polymers. We hypothesize that physisorbed molecular oxygen acts as
an acceptor ($p$-type), compensating the donor-like ($n$-type) defects that are
responsible for the ESR signal in bulk SWCNTs.",1110.5220v1
2013-09-25,Sensing and atomic-scale structure analysis of single nuclear spin clusters in diamond,"Single-molecule nuclear magnetic resonance (NMR) is a crown-jewel challenge
in the field of magnetic resonance spectroscopy and has important applications
in chemical analysis and in quantum computing. Recently, it becomes possible to
tackle this grand challenge thanks to experimental advances in preserving
quantum coherence of nitrogen-vacancy (NV) center spins in diamond as a
sensitive probe and theoretical proposals on atomic-scale magnetometry via
dynamical decoupling control. Through decoherence measurement of NV centers
under dynamical decoupling control, sensing of single $^{13}\textbf{C}$ at
nanometer distance has been realized. Toward the ultimate goal of structure
analysis of single molecules, it is highly desirable to directly measure the
interactions within single nuclear spin clusters. Here we sensed a single
$^{13}\textbf{C}$-$^{13}\textbf{C}$ nuclear spin dimer located about 1 nm from
the NV center and characterized the interaction between the two nuclear spins,
by measuring NV center spin decoherence under various dynamical decoupling
control. From the measured interaction we derived the spatial configuration of
the dimer with atomic-scale resolution. These results demonstrate that central
spin decoherence under dynamical decoupling control is a feasible probe for NMR
structure analysis of single molecules.",1309.6548v1
2016-08-02,RESPECT: Neutron Resonance Spin-Echo Spectrometer for Extreme Studies,"We propose the design of a Resonance SPin-echo spECtrometer for exTreme
studies, RESPECT, that is ideally suited for the exploration of non-dispersive
processes such as diffusion, crystallization, slow dynamics, tunneling
processes, crystal electric field excitations, and spin fluctuations. It is a
variant of the conventional neutron spin-echo technique (NSE) by i) replacing
the long precession coils by pairs of longitudinal neutron spin-echo coils
combined with RF-spin flippers and ii) by stabilizing the neutron polarization
with small longitudinal guide fields that can in addition be used as field
subtraction coils thus allowing to adjust the field integrals over a range of 8
orders of magnitude. Therefore, the dynamic range of RESPECT can in principle
be varied over 8 orders of magnitude in time, if neutrons with the required
energy are made available. Similarly as for existing NSE-spectrometers, spin
echo times of up to approximately 1 microsecond can be reached if the
divergence and the correction elements are properly adjusted. Thanks to the
optional use of neutron guides and the fact that the currents for the
correction coils are much smaller than in standard NSE, intensity gains of at
least one order of magnitude are expected , making the concept of RESPECT also
competitive for operation at medium flux neutron sources. RESPECT can also be
operated in a MIEZE configuration allowing the investigation of relaxation
processes in depolarizing environments as they occur when magnetic fields are
applied at the sample position, i.e. for the investigation of the dynamics of
flux lines in superconductors, magnetic fluctuations in ferromagnetic
materials, and samples containing hydrogen.",1608.00836v1
2016-10-17,Momentum and doping dependence of spin excitations in electron-doped cuprate superconductors,"Superconductivity in copper oxides emerges on doping holes or electrons into
their Mott insulating parent compounds. The spin excitations are thought to be
the mediating glue for the pairing in superconductivity. Here the momentum and
doping dependence of the dynamical spin response in the electron-doped cuprate
superconductors is studied based on the kinetic-energy-driven superconducting
mechanism. It is shown that the dispersion of the low-energy spin excitations
changes strongly upon electron doping, however, the hour-glass-shaped
dispersion of the low-energy spin excitations appeared in the hole-doped side
is absent in the electron-doped case due to the electron-hole asymmetry. In
particular, the commensurate resonance appears in the superconducting-state
with the resonance energy that correlates with the dome-shaped doping
dependence of the superconducting gap. Moreover, the spectral weight and
dispersion of the high-energy spin excitations in the superconducting-state are
comparable with those in the corresponding normal-state, indicating that the
high-energy spin excitations do not play an important part in the pair
formation.",1610.05041v2
2017-08-08,Spin-orbit-torque driven magnetoimpedance in Pt-layer/magnetic-ribbon heterostructures,"When a flow of electron passes through a paramagnetic layer with strong
spin-orbit-coupling such as platinum (Pt), a net spin current is produced via
spin Hall effect (SHE). This spin current can exert a torque on the
magnetization of an adjacent ferromagnetic layer which can be probed via
magnetization dynamic response, e.g. spin-torque ferromagnetic resonance
(ST-FMR). Nevertheless, that effect in lower frequency magnetization dynamic
regime (MHz) where skin effect occurs in high permeability ferromagnetic
conductors namely the magneto-impedance (MI) effect can be fundamentally
important which has not been studied so far. Here, by utilizing the MI effect
in magnetic-ribbon/Pt heterostructure with high magnetic permeability that
allows the ac current effectively confined at the skin depth of ~100 nm
thickness, the effect of spin-orbit-torque (SOT) induced by the SHE probed via
MI measurement is investigated. We observed a systematic MI frequency shift
that increases by increasing the applied current amplitude and thickness of the
Pt layer (varying from 0 nm to 20 nm). In addition, the role of Pt layer in
ribbon/Pt heterostructure is evaluated with ferromagnetic resonance (FMR)
effect representing standard Gilbert damping increase as the result of presence
of the SHE. Our results unveil the role of SOT in dynamic control of the
transverse magnetic permeability probed with impedance spectroscopy as useful
and valuable technique for detection of future SHE devices.",1708.02402v2
2018-03-27,Theory of Hole-Spin Qubits in Strained Germanium Quantum Dots,"We theoretically investigate the properties of holes in a
Si$_{x}$Ge$_{1-x}$/Ge/ Si$_{x}$Ge$_{1-x}$ quantum well in a perpendicular
magnetic field that make them advantageous as qubits, including a large
($>$100~meV) intrinsic splitting between the light and heavy hole bands, a very
light ($\sim$0.05$\, m_0$) in-plane effective mass, consistent with higher
mobilities and tunnel rates, and larger dot sizes that could ameliorate
constraints on device fabrication. Compared to electrons in quantum dots, hole
qubits do not suffer from the presence of nearby quantum levels (e.g., valley
states) that can compete with spins as qubits. The strong spin-orbit coupling
in Ge quantum wells may be harnessed to implement electric-dipole spin
resonance, leading to gate times of several nanoseconds for single-qubit
rotations. The microscopic mechanism of this spin-orbit coupling is discussed,
along with its implications for quantum gates based on electric-dipole spin
resonance, stressing the importance of coupling terms that arise from the
underlying cubic crystal field. Our results provide a theoretical foundation
for recent experimental advances in Ge hole-spin qubits.",1803.10320v5
2019-05-27,The Chaotic Nature of TRAPPIST-1 Planetary Spin States,"The TRAPPIST-1 system has 7 known terrestrial planets arranged compactly in a
mean motion resonant chain around an ultra-cool central star, some within the
estimated habitable zone. Given their short orbital periods of just a few days,
it is often presumed that the planets are tidally locked such that the spin
rate is equal to that of the orbital mean motion. However, the compact, and
resonant, nature of the system implies that there can be significant variations
in the mean motion of these planets due to their mutual interactions. We show
that such fluctuations can then have significant effects on the spin states of
these planets. In this paper, we analyze, using detailed numerical simulations,
the mean motion histories of the three planets that are thought to lie within
or close to the habitable zone of the system: planets d, e, and f. We
demonstrate that, depending on the strength of the mutual interactions within
the system, these planets can be pushed into spin states which are effectively
non-synchronous. We find that it can produce significant libration of the spin
state, if not complete circulation in the frame co-rotating with the orbit. We
also show that these spin states are likely to be unable to sustain long-term
stability, with many of our simulations suggesting that the spin evolves, under
the influence of tidal synchronization forces, into quasi-stable attractor
states, which last on timescales of thousands of years.",1905.11419v2
2021-02-25,Unidirectional magnetoresistance and spin-orbit torque in NiMnSb,"Spin-dependent transport phenomena due to relativistic spin-orbit coupling
and broken space-inversion symmetry are often difficult to interpret
microscopically, in particular when occurring at surfaces or interfaces. Here
we present a theoretical and experimental study of spin-orbit torque and
unidirectional magnetoresistance in a model room-temperature ferromagnet NiMnSb
with inversion asymmetry in the bulk of this half-heusler crystal. Besides the
angular dependence on magnetization, the competition of Rashba and
Dresselhaus-like spin-orbit couplings results in the dependence of these
effects on the crystal direction of the applied electric field. The
phenomenology that we observe highlights potential inapplicability of commonly
considered approaches for interpreting experiments. We point out that, in
general, there is no direct link between the current-induced non-equilibrium
spin polarization inferred from the measured spin-orbit torque and the
unidirectional magnetiresistance. We also emphasize that the unidirectional
magnetoresistance has not only longitudinal but also transverse components in
the electric field -- current indices which complicates its separation from the
thermoelectric contributions to the detected signals in common experimental
techniques. We use the theoretical results to analyze our measurements of the
on-resonance and off-resonance mixing signals in microbar devices fabricated
from an epitaxial NiMnSb film along different crystal directions. Based on the
analysis we extract an experimental estimate of the unidirectional
magnetoresistance in NiMnSb.",2102.12838v1
2021-03-31,Resistively detected NMR as a probe of the topological nature of conducting edge/surface states,"Electron spins in edge or surface modes of topological insulators (TIs) with
strong spin-orbit coupling cannot be directly manipulated with microwaves due
to the locking of electron spin to its momentum. We show by contrast that a
resistively detected nuclear magnetic resonance (RDNMR) based technique can be
used to probe the helical nature of surface conducting states. In such
experiments, one applies a radio frequency (RF) field to reorient nuclear spins
that then couple to electronic spins by the hyperfine interaction. The spin of
the boundary electrons can thereby be modulated, resulting in changes in
conductance at nuclear resonance frequencies. Here, we demonstrate that the
conductivity is sensitive to the direction of the applied magnetic field with
respect to the helicity of the electrons. This dependence of the RDNMR signal
on angle probes the nature of the conductive edge or surface states. In the
case of 3D TI in the quantum Hall regime, we establish that the dominant
mechanism responsible for the conductance change in a RDNMR experiment is based
on the Overhauser field effect. Our findings indicate that the same physics
underlying the use of RDNMR to probe TI states also enables us to use RF
control of nuclear spins to coherently manipulate topologically protected
states which could be useful for a new generation of devices.",2104.00146v2
2021-10-13,Spin-lasing in bimodal quantum dot micropillar cavities,"Spin-controlled lasers are highly interesting photonic devices and have been
shown to provide ultra-fast polarization dynamics in excess of 200 GHz. In
contrast to conventional semiconductor lasers their temporal properties are not
limited by the intensity dynamics, but are governed primarily by the
interaction of the spin dynamics with the birefringent mode splitting that
determines the polarization oscillation frequency. Another class of modern
semiconductor lasers are high-beta emitters which benefit from enhanced
light-matter interaction due to strong mode confinement in low-mode-volume
microcavities. In such structures, the emission properties can be tailored by
the resonator geometry to realize for instance bimodal emission behavior in
slightly elliptical micropillar cavities. We utilize this attractive feature to
demonstrate and explore spin-lasing effects in bimodal high-beta quantum dot
micropillar lasers. The studied microlasers with a beta-factor of 4% show
spin-laser effects with experimental polarization oscillation frequencies up to
15 GHz and predicted frequencies up to about 100 GHz which are controlled by
the ellipticity of the resonator. Our results reveal appealing prospects for
very compact, ultra-fast and energy-efficient spin-lasers and can pave the way
for future purely electrically injected spin-lasers enabled by short injection
path lengths.",2110.06960v1
2008-06-25,Ultrafast control of donor-bound electron spins with single detuned optical pulses,"The ability to control spins in semiconductors is important in a variety of
fields including spintronics and quantum information processing. Due to the
potentially fast dephasing times of spins in the solid state [1-3], spin
control operating on the picosecond or faster timescale may be necessary. Such
speeds, which are not possible to attain with standard electron spin resonance
(ESR) techniques based on microwave sources, can be attained with broadband
optical pulses. One promising ultrafast technique utilizes single broadband
pulses detuned from resonance in a three-level Lambda system [4]. This
attractive technique is robust against optical pulse imperfections and does not
require a fixed optical reference phase. Here we demonstrate the principle of
coherent manipulation of spins theoretically and experimentally. Using this
technique, donor-bound electron spin rotations with single-pulse areas
exceeding pi/4 and two-pulses areas exceeding pi/2 are demonstrated. We believe
the maximum pulse areas attained do not reflect a fundamental limit of the
technique and larger pulse areas could be achieved in other material systems.
This technique has applications from basic solid-state ESR spectroscopy to
arbitrary single-qubit rotations [4, 5] and bang-bang control[6] for quantum
computation.",0806.4137v1
2019-12-22,A single-hole spin qubit,"Qubits based on quantum dots have excellent prospects for scalable quantum
technology due to their inherent compatibility with standard semiconductor
manufacturing. While early on it was recognized that holes may offer a
multitude of favourable properties for fast and scalable quantum control,
research thus far has remained almost exclusively restricted to the simpler
electron system. However, recent developments with holes have led to separate
demonstrations of single-shot readout and fast quantum logic, albeit only in
the multi-hole regime. Here, we establish a single-hole spin qubit in germanium
and demonstrate the integration of single-shot readout and quantum control.
Moreover, we make use of Pauli spin blockade, allowing to arbitrarily set the
qubit resonance frequency, while providing large readout windows. We deplete a
planar germanium double quantum dot to the last hole, confirmed by
radio-frequency reflectrometry charge sensing, and achieve single-shot spin
readout. To demonstrate the integration of the readout and qubit operation, we
show Rabi driving on both qubits and find remarkable electric control over
their resonance frequencies. Finally, we analyse the spin relaxation time,
which we find to exceed one millisecond, setting the benchmark for hole-based
spin qubits. The ability to coherently manipulate a single hole spin underpins
the quality of strained germanium and defines an excellent starting point for
the construction of novel quantum hardware.",1912.10426v2
2020-01-25,Resonant Exchange Operation in Triple-Quantum-Dot Qubits for Spin-Photon Transduction,"Triple quantum dots (TQDs) are promising semiconductor spin qubits because of
their all-electrical control via fast, tunable exchange interactions and
immunity to global magnetic fluctuations. These qubits can experience strong
transverse interaction with photons in the resonant exchange (RX) regime, when
exchange is simultaneously active on both qubit axes. However, most theoretical
work has been based on phenomenological Fermi-Hubbard models, which may not
fully capture the complexity of the qubit spin-charge states in this regime.
Here we investigate exchange in Si/SiGe and GaAs TQDs using full configuration
interaction (FCI) calculations which better describe practical device
operation. We show that high exchange operation in general, and the RX regime
in particular, can differ significantly from simple models, presenting new
challenges and opportunities for spin-photon coupling. We highlight the impact
of device electrostatics and effective mass on exchange and identify a new
operating point (XRX) where strong spin-photon coupling is most likely to occur
in Si/SiGe TQDs. Based on our numerical results, we analyze the feasibility of
a remote entanglement cavity iSWAP protocol and discuss design pathways for
improving fidelity. Our analysis provides insight into the requirements for TQD
spin-photon transduction and demonstrates more generally the necessity of
accurate modeling of exchange in spin qubits.",2001.09240v3
2020-10-15,Longitudinal and transverse electric field manipulation of hole spin-orbit qubits in one-dimensional channels,"Holes confined in semiconductor nanostructures realize qubits where the
quantum mechanical spin is strongly mixed with the quantum orbital angular
momentum. The remarkable spin-orbit coupling allows for fast all electrical
manipulation of such qubits. We study an idealization of a CMOS device where
the hole is strongly confined in one direction (thin film geometry), while it
is allowed to move more extensively along a one-dimensional channel. Static
electric bias and $ac$ electrical driving are applied by metallic gates
arranged along the channel. In quantum devices based on materials with a bulk
inversion symmetry, such as silicon or germanium, there exists different
possible spin-orbit coupling based mechanisms for qubit manipulation. One of
them, the $g$-tensor magnetic resonance ($g$-TMR), relies on the dependence of
the effective $g$-factors on the electrical confinement. In this configuration
the hole is driven by an $ac$ field parallel to the static electric field and
perpendicular to the channel (transverse driving). Another mechanism, which we
refer to here as iso-Zeeman electric dipole spin resonance (IZ-EDSR), is due to
the Rashba spin-orbit coupling that leads to an effective time-dependent
magnetic field experienced by the pseudo-spin oscillating along the quantum
channel (longitudinal driving). We compare these two modes of operation and we
describe the conditions where the magnitudes of the Rabi frequencies are the
largest. Different regimes can be attained by electrical tuning where the
coupling to the $ac$ electric field is made either weak or strong...",2010.07787v2
2023-03-05,Resonant two-laser spin-state spectroscopy of a negatively charged quantum dot-microcavity system with a cold permanent magnet,"A high-efficiency spin-photon interface is an essential piece of quantum
hardware necessary for various quantum technologies. Self-assembled InGaAs
quantum dots have excellent optical properties, if embedded into an optical
micro-cavity they can show near-deterministic spin-photon entanglement and spin
readout, but an external magnetic field is required to address the individual
spin states, which usually is done using a superconducting magnet. Here, we
show a compact cryogenically compatible SmCo magnet design that delivers 475 mT
in-plane Voigt geometry magnetic field at 5 K, which is suitable to lift the
energy degeneracy of the electron spin states and trion transitions of a single
InGaAs quantum dot. This quantum dot is embedded in a birefringent high-finesse
optical micro-cavity which enables efficient collection of single photons
emitted by the quantum dot. We demonstrate spin-state manipulation by
addressing the trion transitions with a single and two laser fields. The
experimental data agrees well to our model which covers single- and two-laser
cross-polarized resonance fluorescence, Purcell enhancement in a birefringent
cavity, and variation of the laser powers.",2303.02763v1
2023-06-20,Spin-orbit interaction enabled electronic Raman scattering from charge collective modes,"Electronic Raman scattering in the fully symmetric channel couples to the
charge excitations in the system, including the plasmons. However, the plasmon
response has a spectral weight of $\sim q^2$, where $q$, the momentum
transferred by light, is small. In this work, we show that in inversion
symmetry broken systems where Rashba type spin-orbit coupling affects the
states at the Fermi energy (which is a known low energy effect) as well as the
transition elements to other states (a high energy effect), there is an
additional coupling of the plasmons to the Raman vertex, even at zero momentum
transfer, that results in a spectral weight that is proportional to the
spin-orbit coupling. The high energy effect is due to the breaking of SU(2)
spin invariance in the spin-flip transitions to the intermediate state. We
present a theory for this coupling near the resonant regime of Raman scattering
and show that in giant Rashba systems it can dominate over the conventional
$q^2$ weighted coupling. We also provide experimental support along with a
symmetry based justification for this spin-mediated coupling by identifying a
prominent c-axis plasmon peak in the fully symmetric channel of the resonant
Raman spectrum of the giant Rashba material BiTeI. This new coupling could lead
to novel ways of manipulating coherent charge excitations in inversion-broken
systems. This process is also relevant for spectroscopic studies in ultrafast
spectroscopies, certain driven Floquet systems and topologically non-trivial
phases of matter where strong inversion-breaking spin-orbit coupling plays a
role.",2306.11240v2
2007-05-10,Some properties of the resonant state in quantum mechanics and its computation,"The resonant state of the open quantum system is studied from the viewpoint
of the outgoing momentum flux. We show that the number of particles is
conserved for a resonant state, if we use an expanding volume of integration in
order to take account of the outgoing momentum flux; the number of particles
would decay exponentially in a fixed volume of integration. Moreover, we
introduce new numerical methods of treating the resonant state with the use of
the effective potential. We first give a numerical method of finding a
resonance pole in the complex energy plane. The method seeks an energy
eigenvalue iteratively. We found that our method leads to a super-convergence,
the convergence exponential with respect to the iteration step. The present
method is completely independent of commonly used complex scaling. We also give
a numerical trick for computing the time evolution of the resonant state in a
limited spatial area. Since the wave function of the resonant state is
diverging away from the scattering potential, it has been previously difficult
to follow its time evolution numerically in a finite area.",0705.1388v2
2012-06-25,Crosstalk Reduction for Superconducting Microwave Resonator Arrays,"Large-scale arrays of Microwave Kinetic Inductance Detectors (MKIDs) are
attractive candidates for use in imaging instruments for next generation
submillimeter-wave telescopes such as CCAT. We have designed and fabricated
tightly packed ~250-pixel MKID arrays using lumped-element resonators etched
from a thin layer of superconducting TiNx deposited on a silicon substrate. The
high pixel packing density in our initial design resulted in large microwave
crosstalk due to electromagnetic coupling between the resonators. Our second
design eliminates this problem by adding a grounding shield and using a
double-wound geometry for the meander inductor to allow conductors with
opposite polarity to be in close proximity. In addition, the resonator
frequencies are distributed in a checkerboard pattern across the array. We
present details for the two resonator and array designs and describe a circuit
model for the full array that predicts the distribution of resonator
frequencies and the crosstalk level. We also show results from a new
experimental technique that conveniently measures crosstalk without the need
for an optical setup. Our results reveal an improvement in crosstalk from 57%
in the initial design down to \leq 2% in the second design. The general
procedure and design guidelines in this work are applicable to future large
arrays employing microwave resonators.",1206.5571v1
2016-06-29,Double resonance response of a superconducting quantum metamaterial: manifestation of non-classical states of photons,"We report a theoretical study of ac response of superconducting quantum
metamaterials (SQMs), i.e. an array of qubits (two-levels system) embedded in
the low-dissipative resonator. By making use of a particular example of SQM,
namely the array of charge qubits capacitively coupled to the resonator, we
obtain a second-order phase transition between an incoherent (the
high-temperature phase) and coherent (the low-temperatures phase) states of
photons. This phase transition in many aspects resembles the
paramagnetic-ferromagnetic phase transition. The critical temperature of the
phase transition, $T^\star$, is determined by the energy splitting of two-level
systems $\delta$, number of qubits in the array $N$, and the strength of the
interaction $\eta$ between qubits and photons in the cavity. We obtain that the
photon states manifest themselves by resonant drops in the frequency dependent
transmission $D(\omega)$ of electromagnetic waves propagating through a
transmission line weakly coupled to the SQM. At high temperatures the
$D(\omega)$ displays a single resonant drop, and at low temperatures a peculiar
\emph{double resonance response} has to be observed. The physical origin of
such a resonant splitting is the quantum oscillations between two coherent
states of photons of different polarizations.",1606.09078v1
2017-06-20,Transition of EMRIs through resonance: corrections to higher order in the on-resonance flux modification,"Extreme mass ratio in-spirals (EMRIs) are candidate events for gravitational
wave detection in the millihertz range (by detectors like LISA and eLISA).
These events involve a stellar-mass black hole, or a similar compact object,
descending in the gravitational field of a supermassive black hole, eventually
merging with it. Properties of the in-spiralling trajectory away from resonance
are well known and have been studied extensively, however little is known about
the behaviour of these binary systems at resonance, when the radial and lateral
frequencies of the orbit become commensurate. We describe the two existing
models, the instantaneous frequency approach used by Gair, Bender, and Yunes,
and the standard two timescales approach implemented by Flanagan and Hinderer.
In both cases, the exact treatment depends on the modelling of the
gravitational self-force, which is currently not available. We extend the
results in Gair, Bender and Yunes to higher order in the on-resonance flux
modification, and argue that the instantaneous frequency approach is also a
valid treatment of the resonance problem. The non-linear differential equations
which arise in treating resonances are interesting from a mathematical view
point. We present our algorithm for perturbative solutions and the results to
third order in the infinitesimal parameter, and discuss the scope of this
approach.",1706.06639v3
2020-03-23,Mathematical analysis of electromagnetic scattering by dielectric nanoparticles with high refractive indices,"In this work, we are concerned with the mathematical modeling of the
electromagnetic (EM) scattering by arbitrarily shaped non-magnetic
nanoparticles with high refractive indices. When illuminated by visible light,
such particles can exhibit a very strong isotropic magnetic response, resulting
from the coupling of the incident wave with the circular displacement currents
of the EM fields. The main aim of this work is to mathematically illustrate
this phenomenon. We shall first introduce the EM scattering resolvent and the
concept of dielectric subwavelength resonances. Then we derive the a priori
estimates for the subwavelength resonances and the associated resonant modes.
We also show the existence of resonances and obtain their asymptotic expansions
in terms of the small particle size and the high contrast parameter. After
that, we investigate the enhancement of the scattering amplitude and the cross
sections when the resonances occur. In doing so, we develop a novel multipole
radiation framework that directly separates the electric and magnetic multipole
moments and allows us to clearly see their orders of magnitude and blow--up
rates. We prove that at the dielectric subwavelength resonant frequencies, the
nanoparticles with high refractive indices behave like the sum of the electric
dipole and the resonant magnetic dipole. Some explicit calculations and
numerical experiments are also provided to validate our general results and
formulas.",2003.10223v2
2020-09-16,Unconventional magnon excitation by off-resonant microwaves,"It is widely recognized that a physical system can only respond to a periodic
driving significantly when the driving frequency matches the normal mode
frequency of the system, which leads to resonance. Off-resonant phenomena are
rarely considered because of the difficulty to realize strong coupling between
physical systems and off-resonant waves. Here we examine the response of a
magnetic system to squeezed light and surprisingly find that the magnons are
maximally excited when the effective driving frequency is several orders of
magnitude larger than the resonant frequency. The generated magnons are
squeezed which brings the advantage of tunable squeezing through an external
magnetic field. Furthermore, we demonstrate that such off-resonant
quasi-particle excitation is universal in all the hybrid systems in which the
coherent and parametric interaction of bosons exists and that it is purely a
quantum effect, which is rooted in the quantum fluctuations of particles in the
squeezed vacuum. Our findings may provide an unconventional route to study
off-resonant phenomena and may further benefit the use of hybrid matter-light
systems in continuous variable quantum information.",2009.07948v2
2019-04-08,Point-dipole approximation for small systems of strongly coupled radiating nanorods,"Systems of closely-spaced resonators can be strongly coupled by interactions
mediated by scattered electromagnetic fields. In large systems the resulting
response has been shown to be more sensitive to these collective interactions
than to the detailed structure of individual resonators. Attempts to describe
such systems have resulted in point-dipole approximations to resonators that
are computationally efficient for large resonator ensembles. Here we provide a
detailed study for the validity of point dipole approximations in small systems
of strongly coupled plasmonic nanorods, including the cases of both
super-radiant and subradiant excitations, where the characteristics of the
excitation depends on the spatial separation between the nanorods. We show that
over an appreciable range of rod lengths centered on $210~\text{nm}$, when the
relative separation $kl$ in terms of the resonance wave number of light $k$
satisfies $kl \gtrsim \pi/2$, the point electric dipole model becomes accurate.
However, when the resonators are closer, the finite-size and geometry of the
resonators modifies the excitation modes, in particular the cooperative mode
line shifts of the point dipole approximation begin to rapidly diverge at small
separations. We also construct simplified effective models by describing a pair
of nanorods as a single effective metamolecule.",1904.03935v1
2019-08-26,Individual nanoantennas empowered by bound states in the continuum for nonlinear photonics,"Bound states in the continuum (BICs) represent localized modes with energies
embedded in the continuous spectrum of radiating waves. BICs were discovered
initially as a mathematical curiosity in quantum mechanics, and more recently
were employed in photonics. Pure mathematical bound states have
infinitely-large quality factors (Q factors) and zero resonant linewidth. In
optics, BICs are physically limited by a finite size, material absorption,
structural disorder, and surface scattering, and they manifest themselves as
the resonant states with large Q factors, also known as supercavity modes or
quasi-BICs. Optical BIC resonances have been demonstrated only in extended 2D
and 1D systems and have been employed for distinct applications including
lasing and sensing. Optical quasi-BIC modes in individual nanoresonators have
been discovered recently but they were never observed in experiment. Here, we
demonstrate experimentally an isolated subwavelength nanoresonator hosting a
quasi-BIC resonance. We fabricate the resonator from AlGaAs material on an
engineered substrate, and couple to the quasi-BIC mode using structured light.
We employ the resonator as a nonlinear nanoantenna and demonstrate record-high
efficiency of second-harmonic generation. Our study brings a novel platform to
resonant subwavelength photonics.",1908.09790v1
2020-05-25,Observation of supercavity modes in subwavelength dielectric resonators,"Electromagnetic response of dielectric resonators with high refractive index
is governed by optically induced electric and magnetic Mie resonances
facilitating confinement of light with the amplitude enhancement. However,
strong subwavelength trapping of light was associated traditionally only with
plasmonic or epsilon-near-zero structures which however suffer from losses.
Recently, an alternative localization mechanism was proposed to trap light in
individual subwavelength optical resonators with a high quality factor in the
regime of a supercavity mode. Here, we present the experimental observation of
the supercavity modes in subwavelength ceramic resonators in the radiofrequency
range. We demonstrate experimentally that the regime of supercavity mode can be
achieved via precise tuning of the resonator's dimensions resulting in a huge
growth of the quality factor reaching the experimental values up to 1.25x10^4,
being limited only by material losses in dielectrics. We reveal that the
supercavity modes can be excited efficiently by both near- and far-fields by
means of dipole sources and plane waves, respectively. In both the cases, the
supercavity mode manifests itself clearly via characteristic peculiarities of
the Fano resonance and radiation patterns. Our work paves the way for future
compact practical devices in photonics and radiophysics.",2006.02262v2
2020-06-08,Applicability of the Rytov full effective-medium formalism to the physical description and design of resonant metasurfaces,"Periodic photonic lattices constitute a fundamental pillar of physics
supporting a plethora of scientific concepts and applications. The advent of
metamaterials and metastructures is grounded in deep understanding of their
properties. Based on the original 1956 formulation by Rytov, it is well known
that a photonic lattice with deep subwavelength periodicity can be approximated
with a homogeneous space having an effective refractive index. Whereas the
attendant effective-medium theory (EMT) commonly used in the literature is
based on the zeroth root, the closed-form transcendental equations possess an
infinite number of roots. Thus far, these higher-order solutions have been
totally ignored; even Rytov himself discarded them and proceeded to approximate
solutions for the deep-subwavelength regime. In spite of the fact that the
Rytov EMT models an infinite half-space lattice, it is highly relevant to
modeling practical thin-film periodic structures with finite thickness as we
show. Therefore, here, we establish a theoretical framework to systematically
describe subwavelength resonance behavior and to predict the optical response
of resonant photonic lattices using the full Rytov solutions. Expeditious
results are obtained with direct, new physical insights available for resonant
lattice properties. We show that the full Rytov formulation implicitly contains
refractive-index solutions pertaining directly to evanescent waves that drive
the laterally-propagating Bloch modes foundational to resonant lattice
properties. In fact, the resonant reradiated Bloch modes experience
wavelength-dependent refractive indices that are solutions of the Rytov
expressions. This insight is useful in modeling guided-mode resonant devices
including wideband reflectors, bandpass filters, and polarizers.",2006.04852v1
2020-12-30,Nonlinear effects in locally-resonant nanostrip phononic metasurface at GHz frequencies,"In this paper, we report on the observation of nonlinear effects in a
nanostrip phononic metasurface (NPM) that enable the tuning of resonance
frequencies at 1.42 GHz. The NPM resonator made of periodic nanostrip array is
fabricated on a lithium niobate substrate. Each of the nanostrip is 250-nm wide
and is made of 680-nm-thick SiO2 layer stacking on 50-nm Al metal electrodes.
Finite element analysis reveals that the device operates in a vertically
polarized (compression) mode with substantial acoustic energy confined in the
nanostrips, leading to a local resonance at low acoustic velocity. Due to the
nonlinearity, the resonance frequency of the device decreases quadratically
with the increase of stimulation power from 10 to 30 dBm. The underlying
mechanism of the nonlinearity is found to be the power-dependent coupling of
the adjacent nanostrips. This coupling induces softening of the substrate
surface region, which reduces the acoustic velocity and hence the bulk
radiation. As a result, the quality factor of the NPM resonator is found to
improve with the increase of stimulation power. The power-dependent coupling of
nanostrips in the NPM resonator demonstrates a reliable method for the
realization of nonlinearity in phononic metasurfaces, which would significantly
enrich the mechanisms for the manipulation of surface acoustic waves at high
frequencies.",2012.15314v1
2020-02-22,Aluminum Nitride Two-Dimensional-Resonant-Rods,"In the last decades, Bulk-Acoustic-Wave (BAW) filters have been essential
components of 1G-to-4G radios. These devices rely on the high electromechanical
coupling coefficient (kt2~7%), attained by Aluminum Nitride (AlN)
Film-Bulk-Acoustic-Resonators (FBARs), to achieve a wideband and low-loss
frequency response. As the resonance frequency of FBARs is set by their
thickness, the integration of multiple FBARs, to form filters, can only be
attained through the adoption of frequency tuning fabrication steps, such as
mass loading or trimming. However, as the ability to reliably control these
steps significantly decays for thinner FBARs, manufacturing FBARs-based
filters, addressing the needs of emerging IoT and 5G high-frequency
applications, is becoming more and more challenging. Consequently, there is a
quest for new acoustic resonant components, simultaneously exhibiting high kt2
and a lithographic frequency tunability. In this work, a novel class of AlN
resonators is presented. These radio-frequency devices, labelled as
Two-Dimensional-Resonant-Rods (2DRRs), exploit, for the first time, the
unconventional acoustic behavior exhibited by a forest of locally resonant
rods, built in the body of a profiled AlN layer that is sandwiched between a
bottom un-patterned metal plate and a top metallic grating. 2DRRs exhibit
unexplored modal features that make them able to achieve high kt2, a
significant lithographic frequency tunability and a relaxed lithographic
resolution, while relying on an optimal AlN crystalline orientation. The
operation of 2DRRs is discussed, in this work, by means of analytical and
finite-element (FE) investigations. The measured performance of the first
fabricated 2DRR, showing a kt2 in excess of 7.4%, are also reported.",2105.11232v1
2021-06-22,Independently reconfigurable internal loss and resonance-shift in an interferometer-embedded optical cavity,"Optical cavities find diverse uses in lasers, frequency combs, optomechanics,
and optical signal processors. Complete reconfigurability of the resonant
frequency as well as the loss enables development of generic field programmable
cavities for achieving the desired performance in these applications.
Conventional reconfigurable cavities are generally limited to specific material
platforms or specific optical tuning methods and require sophisticated
fabrication. Furthermore, the tuning of the loss is coupled to the
resonance-shift in the cavity. We propose and demonstrate a simple and generic
interferometer in a cavity structure that enables quasiperiodic modification of
the internal cavity loss and the cavity resonance to reconfigure the Q-factor,
transmission characteristics, and group delay of the hybrid cavity, with simple
tuning of the optical phase in the interferometer. We also demonstrate methods
to decouple the tuning of the loss from the resonance-shift, that enables
resonance-locked reconfigurability. This structure also enables resonance-shift
to both shorter and longer wavelengths using the same phase-tuning technique,
which is challenging to achieve in conventional reconfigurable cavities. These
devices can be implemented in any guided-wave platform (on-chip or fiber-optic)
with potential applications in programmable photonics and reconfigurable
optomechanics.",2106.12899v3
2021-12-01,Precision measurement of quasi-bound resonances in H$_2$ and the H + H scattering length,"Quasi-bound resonances of H$_2$ are produced via two-photon photolysis of
H$_2$S molecules as reactive intermediates or transition states, and detected
before decay of the parent molecule into three separate atoms. As was
previously reported [K.F. Lai et al., Phys. Rev. Lett. 127, 183001 (2021)] four
centrifugally bound quantum resonances with lifetimes of multiple $\mu$s, lying
energetically above the dissociation limit of the electronic ground state
X$^1\Sigma_g^+$ of H$_2$, were observed as X($v,J$) = (7,21)$^*$, (8,19)$^*$,
(9,17)$^*$, and (10,15)$^*$, while also the short-lived ($\sim 1.5$ ns)
quasi-bound resonance X(11,13)$^*$ was probed. The present paper gives a
detailed account on the identification of the quasi-bound or shape resonances,
based on laser detection via F-X two-photon transitions, and their strongly
enhanced Franck-Condon factors due to the shifting of the wave function density
to large internuclear separation. In addition, the assignment of the rotational
quantum number is verified by subsequent multi-step laser excitation into
autoionization continuum resonances. Existing frameworks of full-fledged ab
initio computations for the bound region in H$_2$, including Born-Oppenheimer,
adiabatic, non-adiabatic, relativistic and quantum-electrodynamic
contributions, are extended into the energetic range above the dissociation
energy. These comprehensive calculations are compared to the accurate
measurements of energies of quasi-bound resonances, finding excellent
agreement. Etc.",2112.00817v1
2022-05-31,Boosted second-harmonic generation in the LiNbO$\mathrm{_3}$ metasurface governed by high-Q guided resonances and bound states in the continuum,"To date, second-harmonic generation (SHG) at nanoscale has been concentrated
on employing high-refractive-index nanostructures, owing to the strong field
confinement at deep subwavelength scales based on optically resonant effects.
However, low-index nanostructures generally exhibit weaker resonant effects and
lower field confinement. To address this issue, by harnessing the large
nonlinearity of LiNbO$\mathrm{_3}$, we propose a novel approach to employ
guided resonances and bound states in the continuum (BICs) with a
LiNbO$\mathrm{_3}$ metasurface consisting of a LiNbO$\mathrm{_3}$ disk array
sitting on a LiNbO3 thin film. Such a system can transform the guided modes
supported by LiNbO$\mathrm{_3}$ thin film into high-quality guided resonances
which can be excited directly under plane-wave illumination. Importantly, we
further demonstrate strong field confinement inside LiNbO3 thin film with
tailorable Q-factor by realising a Friedrich-Wintgen BIC. Such a unique mode
engineering enables a record-high SHG efficiency of 5\% under a pump intensity
as low as 0.4 $\mathrm{MW/cm^{2}}$. Moreover, we reveal the influence of
nonlinear resonances and cross-coupling on the SHG by showing the anomalous SHG
and efficiency tuning with the rotation of the crystal axis. Our work offers a
new route to constructing enhanced SHG based on high-Q guided resonances and
BICs, including low-index and high-index nonlinear materials.",2205.15482v2
2022-10-11,Theory of Truncation Resonances in Continuum Rod-based Phononic Crystals with Generally Asymmetric Unit Cells,"Phononic crystals exhibit Bragg bandgaps, frequency regions within which wave
propagation is forbidden. In solid continua, bandgaps are the outcome of
destructive interferences resulting from periodically alternating layers. Under
certain conditions, natural frequencies emerge within these bandgaps in the
form of high-amplitude localized vibrations near a structural boundary,
referred to as truncation resonances. In this paper, we investigate the
vibrational spectrum of finite phononic crystals which take the form of a
one-dimensional rod, and explain the factors that contribute to the origination
of truncation resonances. By identifying a unit cell symmetry parameter, we
define a family of finite phononic rods which share the same dispersion
relation, yet distinct truncated forms. A transfer matrix method is utilized to
derive closed-form expressions of the characteristic equations governing the
natural frequencies of the finite system and decipher the truncation resonances
emerging across different boundary conditions. The analysis establishes
concrete connections between the localized vibrations associated with a
truncation resonance, boundary conditions, and the overall configuration of the
truncated chain as dictated by unit cell choice. The study provides tools to
predict, tune, and selectively design truncation resonances, to meet the
demands of various applications that require and uniquely benefit from such
truncation resonances.",2211.01423v3
2022-11-06,Fano resonances in all-dielectric electromagnetic metasurfaces,"We are interested in the resonant electromagnetic (EM) scattering by
all-dielectric metasurfaces made of a two-dimensional lattice of nanoparticles
with high refractive indices. In [Ammari et al., Trans. AMS, 376 (2023),
39-90], it has been shown that a single high-index nanoresonator can couple
with the incident wave and exhibit a strong magnetic dipole response. Recent
physics experiments reveal that when the particles are arranged in certain
periodic configurations, they may have different anomalous scattering effects
in the macroscopic scale, compared to the single-particle case. In this work,
we shall develop a rigorous mathematical framework for analyzing the resonant
behaviors of all-dielectric metasurfaces. We start with the characterization of
subwavelength scattering resonances in such a periodic setting and their
asymptotic expansions in terms of the refractive index of the nanoparticles.
Then we show that real resonances always exist below the essential spectrum of
the periodic Maxwell operator and that they are the simple poles of the
scattering resolvent with the exponentially decaying resonant modes. By using
group theory, we discuss the implications of the symmetry of the metasurface on
the subwavelength band functions and their associated eigenfunctions. For the
symmetric metasurfaces with the normal incidence, we use a variational method
to show the existence of embedded eigenvalues (i.e., real subwavelength
resonances embedded in the continuous radiation spectrum). Furthermore, we
break the configuration symmetry either by introducing a small deformation of
particles or by slightly deviating from the normal incidence and prove that
Fano-type reflection and transmission anomalies can arise in both of these
scenarios.",2211.03224v3
2023-05-17,Do different kinds of photon-pair sources have the same indistinguishability in quantum silicon photonics?,"In the same silicon photonic integrated circuit, we compare two types of
integrated degenerate photon-pair sources (microring resonators or waveguides)
by means of Hong-Ou-Mandel (HOM) interference experiments. Two nominally
identical microring resonators are coupled to two nominally identical
waveguides which form the arms of a Mach-Zehnder interferometer. This is pumped
by two lasers at two different wavelengths to generate, by spontaneous
four-wave mixing, degenerate photon pairs. In particular, the microring
resonators can be thermally tuned in or out of resonance with the pump
wavelengths, thus choosing either the microring resonators or the waveguides as
photon-pair sources, respectively. In this way, an on-chip HOM visibility of
94% with microring resonators and 99% with straight waveguides is measured upon
filtering. We compare our experimental results with theoretical simulations of
the joint spectral intensity and the purity of the degenerate photon pairs. We
verify that the visibility is connected to the sources' indistinguishability,
which can be quantified by the overlap between the joint spectral amplitudes
(JSA) of the photon pairs generated by the two sources. We estimate a JSAs
overlap of 98% with waveguides and 89% with microring resonators.",2305.10066v2
2023-06-14,Fano resonances for tilted linear and quadratic band touching dispersions in a harmonically driven potential well,"Considering models with tilted linear and quadratic band touching
dispersions, we analyze the effect of the transverse linear tilt on the
transmission spectra through a harmonically driven potential well oriented
longitudinally. Employing the Floquet scattering matrix formalism, we find Fano
resonances as an outcome of matching between the Floquet sidebands and
quasi-bound states, where the tilt renormalizes their energies and wave
vectors. We find that the Fano resonance energy decreases (increases) for
linear (quadratic) band touchings as the magnitude of the transverse momentum
increases, indicating a distinct signature of the underlying band dispersion in
the transmission profile. The sign of the product of the transverse momentum
and the tilt also determines the relative shift in the Fano resonance energy
with respect to the untilted case for both band dispersions, suggesting a
possible tunability of the Fano resonance for tilted systems. Importantly, the
tilt strength can also be directly determined by measuring the Fano resonance
energy as function of the transverse momenta direction. We furthermore study
the shot noise spectra and their differential property where we find an
inflection region and undulation, respectively, around the Fano resonance
energy. Interestingly, differential shot noise and transmission spectra both
qualitatively behave in a similar fashion and might thus serve as important
observables for future experiments on driven solid-state systems.",2306.08759v2
2024-02-23,Variation in whispering gallery mode of resonance in a trapped and levitated liquid micro cavity,"Whispering gallery mode (WGM) of resonance occurs when a traveling wave faces
grazing reflection and confinement at the inner surface of a spherical cavity.
Such a resonance was observed with micrometer sized liquid droplet and with
light of sub-micron wavelength. The resonance occurs when specific boundary
conditions are fulfilled, following a relation between optical path length
(that is related to radius of the droplet) and resonating wavelength.
Therefore, a change in WGM wavelength will be related to dimension of the
droplet. We observed a shift in such a resonance spectra. For a smaller droplet
the observed blue shift in the WGM were 1.5, 0.7, 3.7 nm. Following the
resonance condition, it was estimated that such a shift corresponds to a
reduction in radius of the droplet by 1.3, 0.6, 3.3 nm respectively. This was
obtained with a droplet of radius about 600 nm. The droplet was created from a
solution of glycerol, methanol and rhodamine 6G dye, and was trapped and
levitated in a modified Paul trap. The WGMs were created by optically exciting
the dye material from an external 532 nm cw laser beam. A shift in the WGM was
observed with time, during a gradual increase in power of the excitation laser,
and a reason for such a shift was thought to be thermal evaporation of the
liquid from the droplet. For a larger droplet an initial 0.1 nm thermal
expansion was also estimated because initially a red-shift of the WGM was
observed, probably because of thermal expansion, which was negligible for a
smaller droplet. For the smaller droplet, the estimated rate of change of WGM
with radius, was 1.129. For larger droplet, this rate is lower.",2402.15291v1
2005-02-11,A Weakly Nonlinear Analysis of Impulsively-Forced Faraday Waves,"Parametrically-excited surface waves, forced by a periodic sequence of
delta-function impulses, are considered within the framework of the
Zhang-Vi\~nals model (J. Fluid Mech. 1997). The exact impulsive-forcing
results, in the linear and weakly nonlinear regimes, are compared with
numerical results for sinusoidal and multifrequency forcing. We find
surprisingly good agreement between impulsive forcing results and those
obtained using a two-term truncated Fourier series representation of the
impulsive forcing function. As noted previously by Bechhoefer and Johnson (Am.
J. Phys. 1996), in the case of two equally-spaced impulses per period there are
only subharmonic modes of instability. The familiar situation of alternating
subharmonic and harmonic resonance tongues emerges for unequally-spaced
impulses. We extend the linear analysis for two impulses per period to the
weakly nonlinear regime for one-dimensional waves. Specifically, we derive an
analytic expression for the cubic Landau coefficient in the bifurcation
equation as a function of the dimensionless fluid parameters and spacing
between the two impulses. As the capillary parameter is varied, one finds a
parameter region of wave amplitude suppression, which is due to a familiar 1:2
spatio-temporal resonance between the subharmonic mode of instability and a
damped harmonic mode. This resonance occurs for impulsive forcing even when
harmonic resonance tongues are absent from the neutral stability curve. The
strength of this resonance feature can be tuned by varying the spacing between
the impulses. This finding is interpreted in terms of a recent symmetry-based
analysis of multifrequency forced Faraday waves by Porter, Topaz and Silber
(Phys. Rev. Lett. 2004, Phys. Rev. E 2004).",0502025v1
2005-01-04,Wakes in Dark Matter Halos,"I discuss the dynamical interaction of galactic disks with the surrounding
dark matter halos. In particular it is demonstrated that if the
self-gravitating shearing sheet, a model of a patch of a galactic disk, is
embedded in a live dark halo, this has a strong effect on the dynamics of
density waves in the sheet. I describe how the density waves and the halo
interact via halo particles either on orbits in resonance with the wave or on
non-resonant orbits. Contrary to expectation the presence of the halo leads to
a very considerable enhancement of the amplitudes of the density waves in the
shearing sheet. This effect appears to be the equivalent of the recently
reported enhanced growth of bars in numerically simulated stellar disks
embedded in live dark halos. Finally I discuss the counterparts of the
perturbations of the disk in the dark halo.",0501050v1
2006-08-10,Charge modulations vs. strain waves in resonant x-ray scattering,"A method is described for using resonant x-ray scattering to separately
quantify the charge (valence) modulation and the strain wave associated with a
charge density wave. The essence of the method is a separation of the atomic
form factor into a ""raw"" amplitude, fR(w), and a valence-dependent amplitude,
fD(w), which in many cases may be determined independently from absorption
measurements. The advantage of this separation is that the strain wave follows
the quantity |fR(w) + <v> fD(w)|^2 whereas the charge modulation follows only
|fD(w)|^2. This allows the two distinct modulations to be quantified
separately. A scheme for characterizing a given CDW as Peierls-like or
Wigner-like naturally follows. The method is illustrated for an idealized model
of a one-dimensional chain.",0608236v1
2007-03-12,First Cross-Correlation Analysis of Interferometric and Resonant-Bar Gravitational-Wave Data for Stochastic Backgrounds,"Data from the LIGO Livingston interferometer and the ALLEGRO resonant bar
detector, taken during LIGO's fourth science run, were examined for
cross-correlations indicative of a stochastic gravitational-wave background in
the frequency range 850-950 Hz, with most of the sensitivity arising between
905 Hz and 925 Hz. ALLEGRO was operated in three different orientations during
the experiment to modulate the relative sign of gravitational-wave and
environmental correlations. No statistically significant correlations were seen
in any of the orientations, and the results were used to set a Bayesian 90%
confidence level upper limit of Omega_gw(f) <= 1.02, which corresponds to a
gravitational wave strain at 915 Hz of 1.5e-23/rHz. In the traditional units of
h_100^2 Omega_gw(f), this is a limit of 0.53, two orders of magnitude better
than the previous direct limit at these frequencies. The method was also
validated with successful extraction of simulated signals injected in hardware
and software.",0703068v1
2007-02-25,Chaotic Scattering and the $n$-bounce Resonance in Solitary Wave Interactions,"We present a new and complete analysis of the n-bounce resonance and chaotic
scattering in solitary wave collisions. In these phenomena, the speed at which
a wave exits a collision depends in a complicated fractal way on its input
speed. We present a new asymptotic analysis of collective-coordinate ODEs,
reduced models that reproduce the dynamics of these systems. We reduce the ODEs
to discrete-time iterated separatrix maps and obtain new quantitative results
unraveling the fractal structure of the scattering behavior. These phenomena
have been observed repeatedly in many solitary-wave systems over 25 years.",0702048v1
2005-09-26,Role of low-$l$ component in deformed wave functions near the continuum threshold,"The structure of deformed single-particle wave functions in the vicinity of
zero energy limit is studied using a schematic model with a quadrupole deformed
finite square-well potential. For this purpose, we expand the single-particle
wave functions in multipoles and seek for the bound state and the Gamow
resonance solutions. We find that, for the $K^{\pi}=0^{+}$ states, where $K$ is
the $z$-component of the orbital angular momentum, the probability of each
multipole components in the deformed wave function is connected between the
negative energy and the positive energy regions asymptotically, although it has
a discontinuity around the threshold. This implies that the $K^{\pi}=0^{+}$
resonant level exists physically unless the $l=0$ component is inherently large
when extrapolated to the well bound region. The dependence of the multipole
components on deformation is also discussed.",0509068v1
1998-07-15,Beam Instabilities in Magnetized Pair Plasma,"Beam instabilities in the strongly magnetized electron-positron plasma of
pulsar magnetospheres are considered. We analyze the resonance conditions and
estimate the growth rates of the Cherenkov and cyclotron instabilities of the
ordinary (O), extraordinary (X) and Alfv\'{e}n modes in two limiting regimes:
kinetic and hydrodynamic. As a preliminary step, we reconsider wave dispersion
and polarization properties in a one dimensional pair plasma taking into
account relativistic thermal effects. We then find the location of the
Cherenkov and cyclotron resonance of the X, O and Alfv\'{e}n waves with the
particles from the primary beam. The importance of the different instabilities
as a source of the coherent pulsar radiation generation is then estimated
taking into account the angular dependence of the growth rates and the
limitations on the length of the coherent wave-particle interaction imposed by
the curvature of the magnetic field lines. We conclude, that in the pulsar
magnetosphere the Cherenkov-type instabilities occur in the hydrodynamic
regimes, while the cyclotron-type instabilities occur in the kinetic regime. We
argue, that electromagnetic cyclotron-type instabilities on the X, O and
probably Alfv\'{e}n waves are more likely to develop in the pulsar
magnetosphere.",9807022v1
2000-11-15,Theory of self phase-locked optical parametric oscillators,"The plane-wave dynamics of 3*omega => (2*omega, omega) subharmonic optical
parametric oscillators containing a second harmonic generator of the idler wave
omega is analyzed analytically by using the meanfield approximation and
numerically by taking into account the field propagation inside the media. The
resonant Chi(2):Chi(2) cascaded second-order nonlinearities induce a mutual
injection-locking of the signal and idler waves that leads to coherent self
phase-locking of the pump and subharmonic waves, freezing the phase diffusion
noise. In case of signal-and-idler resonant devices, largely detuned
sub-threshold states occur due to a subcritical bifurcation, broadening out the
self-locking frequency range to a few cavity linewidths.",0011034v1
2001-11-07,Polarisation Patterns and Vectorial Defects in Type II Optical Parametric Oscillators,"Previous studies of lasers and nonlinear resonators have revealed that the
polarisation degree of freedom allows for the formation of polarisation
patterns and novel localized structures, such as vectorial defects. Type II
optical parametric oscillators are characterised by the fact that the
down-converted beams are emitted in orthogonal polarisations. In this paper we
show the results of the study of pattern and defect formation and dynamics in a
Type II degenerate optical parametric oscillator for which the pump field is
not resonated in the cavity. We find that traveling waves are the predominant
solutions and that the defects are vectorial dislocations which appear at the
boundaries of the regions where traveling waves of different phase or
wave-vector orientation are formed. A dislocation is defined by two topological
charges, one associated with the phase and another with the wave-vector
orientation. We also show how to stabilize a single defect in a realistic
experimental situation. The effects of phase mismatch of nonlinear interaction
are finally considered.",0111023v1
2001-11-09,Readout and Control of a Power-recycled Interferometric Gravitational-wave Antenna,"Interferometric gravitational wave antennas are based on Michelson
interferometers whose sensitivity to small differential length changes has been
enhanced by adding multiple coupled optical resonators. The use of optical
cavities is essential for reaching the required sensitivity, but sets
challenges for the control system which must maintain the cavities near
resonance. The goal for the strain sensitivity of the Laser Interferometer
Gravitational-wave Observatory (LIGO) is 10^-21 rms, integrated over a 100 Hz
bandwidth centered at 150 Hz. We present the major design features of the LIGO
length and frequency sensing and control system which will hold the
differential length to within 5 10^-14 m of the operating point. We also
highlight the restrictions imposed by couplings of noise into the gravitational
wave readout signal and the required immunity against them.",0111047v1
2005-10-15,"On de Broglie's soliton wave function of many particles with finite masses, energies and momenta","We consider a mass-less manifestly covariant {\it linear} Schr\""odinger
equation. First, we show that it possesses a class of non-dispersive soliton
solution with finite-size spatio-temporal support inside which the quantum
amplitude satisfies the Klein-Gordon equation with finite {\it emergent} mass.
We then proceed to interpret the soliton wave function as describing a particle
with finite mass, energy and momentum. Inside the spatio-temporal support, the
wave function shows spatio-temporal internal vibration with angular frequency
and wave number that are determined by the energy-momentum of the particle as
firstly conjectured by de Broglie. Imposing resonance of the internal vibration
inside the spatio-temporal support leads to Planck-Einstein quantization of
energy-momentum. The first resonance mode is shown to recover the classical
energy-momentum relation developed in special relativity. We further show that
the linearity of the Schr\""odinger equation allows one to construct many
solitons solution through superposition, each describing a particle with
various masses, energies and momenta.",0510117v3
2006-05-17,A quasi-Hermitian pseudopotential for higher partial wave scattering,"We formulate a new quasi-Hermitian delta-shell pseudopotential for higher
partial wave scattering, and show that any such potential must have an
energy-dependent regularization. The quasi-Hermiticity of the Hamiltonian leads
to a complete set of biorthogonal wave functions that can be used as a basis to
expand and diagonalize other two-body Hamiltonians. We demonstrate this
procedure for the case of ultracold atoms in a polarization-gradient optical
lattice, interacting pairwise when two atoms are transported together from
separated lattice sites. Here the pseudopotential depends explicitly on the
trapping potential. Additionally, we calculate the location of trap-induced
resonances for higher partial waves, which occur when a molecular eigenstate is
shifted to resonance with a trap eigenstate. We verify the accuracy of the
pseudopotential approach using a toy model in which a square well acts as the
true interaction potential, and see excellent agreement.",0605147v3
2007-06-06,Nonlocal Phenomenology for anisotropic MHD turbulence,"A non-local cascade model for anisotropic MHD turbulence in the presence of a
guiding magnetic field is proposed. The model takes into account that (a)
energy cascades in an anisotropic manner and as a result a different estimate
for the cascade rate in the direction parallel and perpendicular to the guiding
field is made. (b) the interactions that result in the cascade are between
different scales. Eddies with wave numbers $k_\|$ and $k_\perp$ interact with
eddies with wave numbers $q_\|,q_\perp$ such that a resonance condition between
the wave numbers $q_\|,q_\perp$ and $k_\|,k_\perp$ holds. As a consequence
energy from the eddy with wave numbers $k_\|$ and $k_\perp$ cascades due to
interactions with eddies located in the resonant manifold whose wavenumbers are
determined by: $q_\|\simeq \epsilon^{{1}/{3}}k_\perp^{2/3}/B$,
$q_\perp=k_\perp$ and energy will cascade along the lines $k_\|\sim
C+k_\perp^{2/3} \epsilon^{1/3}/B_0$. For a uniform energy injection rate in the
parallel direction the resulting energy spectrum is $E(k_\|,k_\perp)\simeq
\epsilon^{2/3}k_\|^{-1}k_\perp^{-5/3}$. For a general forcing however the model
suggests a non-universal behavior. The connections with previous models,
numerical simulations and weak turbulence theory are discussed.",0706.0816v1
2007-09-06,Amplification of compressional MHD waves in systems with forced entropy oscillations,"The propagation of compressional MHD waves is studied for an externally
driven system. It is assumed that the combined action of the external sources
and sinks of the entropy results in the harmonic oscillation of the entropy
(and temperature) in the system. It is found that with the appropriate resonant
conditions fast and slow waves get amplified due to the phenomenon of
parametric resonance. Besides, it is shown that the considered waves are
mutually coupled as a consequence of the nonequilibrium state of the background
medium. The coupling is strongest when the plasma $\beta \approx 1$. The
proposed formalism is sufficiently general and can be applied for many
dynamical systems, both under terrestrial and astrophysical conditions.",0709.0846v1
2007-11-18,Gamma Standing Wave in the Photonic Crystal of Resonant Rh Nuclei,"In a previous report, we have shown that the rhodium lattice consisting of
resonant nuclei is an ideal photonic crystal in nature. Plenty of extraordinary
observations are attributed to the collective down conversion of the multipolar
nuclear transition; in particular the spontaneous open up of photonic band gap.
Emissions of directionality depending on the macroscopic geometry manifest that
the standing wave is global in the polycrystalline sample. In this work,
further observations of the directional emissions are summarized. By applying
an external magnetic field at room temperature, not only the predicted
macroscopic nuclear polarization but also its strong directionality are
demonstrated. The standing wave lasts for more than hundred hours at room
temperature in the single crystal despite its natural half-life of one hour.
The so-called nuclear Raman Effect between two M4 transitions of 193mIr and
195mPt and the E3 transition of 103mRh is discovered, which gives the brand new
aspects to detect gravitational waves.",0711.2776v1
2008-01-18,Modélisation de la propagation dans une structure fermée surdimensionnée,"The propagation of an electromagnetic wave in closed structures led to
numerous applications ranging from the characterization of materials in
resonating cavities to the measurements using pregnant reverberant EMF. We
created models to study the existence of electromagnetic waves in large closed
structures. There are two ways of excitation in such structures. One of these
methods is based on continuous excitation with specific resonant modes, which
has a variety of applications. The second method consists of a pulsed
excitation similar to the impulse wave radar. This excitation provides other
information. The structures studied were closed by perfectly conducting walls
and the electromagnetic wave was generated in the structure using dipole
antennas. The dimensions (length, width and height) were always much larger
than the wavelength.",0801.2853v1
2008-05-06,Events trigger generator for resonant spherical detectors of gravitational waves,"We have set up and tested a pipeline for processing the data from a spherical
gravitational wave detector with six transducers. The algorithm exploits the
multichannel capability of the system and provides a list of candidate events
with their arrival direction. The analysis starts with the conversion of the
six detector outputs into the scalar and the five quadrupolar modes of the
sphere, which are proportional to the corresponding gravitational wave
spherical components. Event triggers are then generated by an adaptation of the
WaveBurst algorithm. Event validation and direction reconstruction are made by
cross-checking two methods of different inspiration: geometrical (lowest
eigenvalue) and probabilistic (maximum likelihood). The combination of the two
methods is able to keep substantially unaltered the efficiency and can reduce
drastically the detections of fake events (to less than ten per cent). We show
a quantitative test of these ideas by simulating the operation of the resonant
spherical detector miniGRAIL, whose planned sensitivity in its frequency band
(few hundred Hertz's around 3 kHz) is comparable with the present LIGO one.",0805.0718v2
2008-08-14,Resonant nonlinear optics of backward waves in negative-index metamaterials,"The extraordinary properties of resonant four-wave mixing of backward waves
in doped negative-index materials are investigated. The feasibility of
independent engineering of negative refractive index and nonlinear optical
response as well as quantum control of the nonlinear propagation process in
such composites is shown due to the coherent energy transfer from the control
to the signal field. Laser-induced transparency, quantum switching,
frequency-tunable narrow-band filtering, amplification, and realizing a
miniature mirrorless optical parametric generator of the entangled backward and
ordinary waves are among the possible applications of the investigated
processes.",0808.2038v1
2008-09-19,Dynamics of Asymptotically Hyperbolic Manifolds,"We prove a dynamical wave trace formula for asymptotically hyperbolic (n+1)
dimensional manifolds with negative (but not necessarily constant) sectional
curvatures which equates the renormalized wave trace to the lengths of closed
geodesics. A corollary of this dynamical trace formula is a dynamical
resonance-wave trace formula for compact perturbations of convex co-compact
hyperbolic manifolds which we use to prove a growth estimate for the length
spectrum counting function. We next define a dynamical zeta function and prove
its analyticity in a half plane. In our main result, we produce a prime orbit
theorem for the geodesic flow. This is the first such result for manifolds
which have neither constant curvature nor finite volume. As a corollary to the
prime orbit theorem, using our dynamical resonance-wave trace formula, we show
that the existence of pure point spectrum for the Laplacian on negatively
curved compact perturbations of convex co-compact hyperbolic manifolds is
related to the dynamics of the geodesic flow.",0809.3472v2
2008-12-28,Propagation of extremely short electromagnetic pulses in a doubly-resonant medium,"Propagation of extremely short electromagnetic pulses in a homogeneous
doubly-resonant medium is considered in the framework of the total
Maxwell-Duffing-Lorentz model, where the Duffing oscillators (anharmonic
oscillators with cubic nonlinearities) represent the dielectric response of the
medium, and the Lorentz harmonic oscillators represent the magnetic response.
The wave propagation is governed by the one-dimensional Maxwell equations.
  It is shown that the model possesses a one-parameter family of traveling-wave
solutions with the structure of single or multiple humps. Solutions are
parametrized by the velocity of propagation. The spectrum of possible
velocities is shown to be continuous on a small interval at the lower end of
the spectrum; elsewhere the velocities form a discrete set. A correlation
between the number of humps and the velocity is established. The traveling-wave
solutions are found to be stable with respect to weak perturbations. Numerical
simulations demonstrate that the traveling-wave pulses collide in a nearly
elastic fashion.",0812.4794v1
2009-01-31,Formation of a Direct Kolmogorov-like Cascade of Second Sound Waves in He II,"Based on measurements of nonlinear second sound resonances in a high-quality
resonator, we have observed a steady-state wave energy cascade in He II
involving a flux of energy through the spectral range towards high frequencies.
We show that the energy balance in the wave system is nonlocal in K-space and
that the frequency scales of energy pumping and dissipation are widely
separated. The wave amplitude distribution follows a power law over a wide
range of frequencies. Numerical computations yield results in agreement with
the experimental observations. We suggest that second sound cascades of this
kind may be useful for model studies of acoustic turbulence.",0902.0029v1
2009-11-23,Couplings in coupled channels versus wave functions: application to the X(3872) resonance,"We perform an analytical study of the scattering matrix and bound states in
problems with many physical coupled channels. We establish the relationship of
the couplings of the states to the different channels, obtained from the
residues of the scattering matrix at the poles, with the wave functions for the
different channels. The couplings basically reflect the value of the wave
functions around the origin in coordinate space. In the concrete case of the
X(3872) resonance, understood as a bound state of $\ddn$ and $\ddc$ (and
$c.c.$), with the $\ddn$ loosely bound, we find that the couplings to the two
channels are essentially equal leading to a state of good isospin I=0
character. This is in spite of having a probability for finding the $\ddn$
state much larger than for $\ddc$ since the loosely bound channel extends
further in space. The analytical results, obtained with exact solutions of the
Schr\""odinger equation for the wave functions, can be useful in general to
interpret results found numerically in the study of problems with unitary
coupled channels methods.",0911.4407v2
2010-01-28,Response and Amplification of Terahertz Electromagnetic Waves in Intrinsic Josephson Junctions of Layered High-Tc Superconductor,"We investigate the response of a stack of intrinsic Josephson junctions
(IJJs) to terahertz (THz) electromagnetic (EM) irradiation. A significant
amplification of the EM wave can be achieved by the IJJs stack when the
incident frequency equals to one of the cavity frequencies. The irradiation
excites pi phase kinks in the junctions, which stimulate the cavity resonance
when the bias voltage is tuned. A large amount of dc energy is then pumped into
the Josephson plasma oscillation, and the incident wave gets amplified. From
the profound current step in IV characteristics induced at the cavity
resonance, the system can also be used for detection of the THz wave.",1001.5119v2
2010-05-14,Amplification of Acoustic Wave in GaN in the Presence of Slowly Changing Periodic Electric Field,"Acoustic wave propagation in bulk GaN Semiconductor in the presence of a
slowly changing a.c electric field and a constant electric field has been
studied. Analytical expression for the attenuation (amplification) coefficient
has been obtained. It is shown that the a.c electric field is acting as a
modulator and that the acoustoelectric gain increases to a maximum value and
then fall off as the acoustic wave frequency is increased. Also for a a.c
electric field of 4 x 104 V/CM the acoustoelectric gain remains zero until the
acoustic wave frequency is about 5.8x1012Hz then a resonant amplification peak
appears. If the a.c electric field is increased a second resonant peak accurs
at 8.7x1012Hz. It is therefore suggested that the sample can be used as a
maser.",1005.2574v1
2012-01-19,Wave Leakage and Resonant Absorption in a Loop Embedded in a Coronal Arcade,"We investigate the temporal evolution of impulsively generated perturbations
in a potential coronal arcade with an embedded loop. As the initial
configuration we consider a coronal loop, represented by a density enhancement,
which is unbounded in the ignorable direction of the arcade. The linearized
time-dependent magnetohydrodynamic equations have been numerically solved in
field-aligned coordinates and the time evolution of the initial perturbations
has been studied in the zero-beta approximation. For propagation constrained to
the plane of the arcade, the considered initial perturbations do not excite
trapped modes of the system. This weakness of the model is overcome by the
inclusion of wave propagation in the ignorable direction. The inclusion of
perpendicular propagation produces two main results. First, damping by wave
leakage is less efficient because the loop is able to act as a wave trap of
vertical oscillations. Second, the consideration of an inhomogeneous corona
enables the resonant damping of vertical oscillations and the energy transfer
from the interior of the loop to the external coronal medium.",1201.4042v1
2012-10-01,Air-coupled thickness measurements of stainless steel,"A method of measuring the thickness of steel plates using through
transmission of an acoustic pulse is demonstrated. This study has been done on
a stainless steel plate with regions of thickness 10:0 mm, 9:8 mm, and 9:6 mm,
using broadband pulses with energy in 200 kHz to 600 kHz band. Ultimately the
goal is to perform similar air-coupled thickness measurements in a single sided
pitch-catch measurement setup.
  The spectra of the transmitted pulses show the first and second harmonics of
the compressional waves in the plate. When compared to a plane wave model of a
fluid layer embedded in air, the second harmonic of the plate resonance fits
well with the expected value. However, the first harmonic deviates such that
the plate appears thicker at this resonance. This is believed to be caused by
the finite aperture of the transmitting transducer, causing deviations from a
plane wave. Thickness differences of 0:2 mm between the different regions of
the plate were shown to be resolved.
  A third peak was found in the spectra. The origin of this peaks has not been
verified, but is believed to come from the third harmonic of the shear wave in
the steel plate.",1210.0428v1
2012-10-09,N-order bright and dark rogue waves in a Resonant erbium-doped Fibre system,"The rogue waves in a resonant erbium-doped fibre system governed by a coupled
system of the nonlinear Schr\""odinger equation and the Maxwell-Bloch equation
(NLS-MB equations) are given explicitly by a Taylor series expansion about the
breather solutions of the normalized slowly varying amplitude of the complex
field envelope $E$, polarization $p$ and population inversion $\eta$. The
n-order breather solutions of the three fields are constructed using Darboux
transformation (DT) by assuming periodic seed solutions. What is more, the
n-order rogue waves are given by determinant forms with $n+3$ free parameters.
Furthermore, the possible connection between our rouge waves and the generation
of supercontinuum generation is discussed.",1210.2522v2
2014-05-14,Simultaneous Resonant Excitation of Low-frequency Eccentric Wave and Tilt Wave on Tidally Deformed Disks,"Simultaneous excitation of low-frequency eccentric precessing mode (one-armed
p-mode) and tilt mode on tidally deformed disks is considered. If the orbit of
the secondary star is eccentric and its orbital plane is misaligned with the
disk plane of the primary, the above-mentioned two low-frequency oscillation
modes are simultaneously excited on the primary disk, the former having
prograte precession and the latter having retrograde precession. This
excitation of disk oscillations is due to a wave-wave resonant excitation
process considered by Kato (2013). If parameter values relevant to Be/X-ray
binary systems are adopted, the periods of these excited oscillations are
around ten times of the orbital period of the secondary, which may be
comparable with the time scale of giant outbursts observed in Be/X-ray systems.",1405.3372v1
2014-07-28,Biharmonic Split Ring Resonator Metamaterial: Artificially dispersive effective density in thin periodically perforated plates,"We present in this paper a theoretical and numerical analysis of bending
waves localized on the boundary of a platonic crystal whose building blocks are
split ring resonators (SRR). We first derive the homogenized parameters of the
structured plate using a three-scale asymptotic expansion in the linearized
biharmonic equation. In the limit when the wavelength of the bending wave is
much larger than the typical heterogeneity size of the platonic crystal, we
show that it behaves as an artificial plate with an anisotropic effective Young
modulus and a dispersive effective mass density. We then analyze dispersion
diagrams associated with bending waves propagating within an infinite array of
SRR, for which eigen-solutions are sought in the form of Floquet-Bloch waves.
We finally demonstrate that this structure displays the hallmarks of
All-Angle-Negative-Refraction(AANR) and it leads to superlensing and
ultrarefraction effects, interpreted thanks to our homogenization model as a
consequence of negative and vanishing effective density, respectively.",1408.0004v1
2014-12-10,Wave-particle interactions with parallel whistler waves: nonlinear and time-dependent effects revealed by Particle-in-Cell simulations,"We present a self-consistent Particle-in-Cell simulation of the resonant
interactions between anisotropic energetic electrons and a population of
whistler waves, with parameters relevant to the Earths radiation belt. By
tracking PIC particles, and comparing with test-particle simulations we
emphasize the importance of including nonlinear effects and time evolution in
the modeling of wave-particle interactions, which are excluded in the resonant
limit of quasi- linear theory routinely used in radiation belt studies. In
particular we show that pitch angle diffusion is enhanced during the linear
growth phase, and it rapidly saturates well before a single bounce period. This
calls into question the widely used bounce average performed in most radiation
belt diffusion calculations. Furthermore we discuss how the saturation is
related to the fact that the domain in which the,particles pitch angle diffuse
is bounded, and to the well-known problem of $90^\circ$ diffusion barrier
diffusion barrier.",1412.3229v2
2015-02-11,Resonance expansions for tensor-valued waves on asymptotically Kerr-de Sitter spaces,"In recent joint work with Vasy, we analyze the low energy behavior of
differential form-valued waves on black hole spacetimes. In order to deduce
asymptotics and decay from this, one in addition needs high energy estimates
for the wave operator acting on sections of the form bundle. The present paper
provides these on perturbations of Schwarzschild-de Sitter spaces in all
spacetime dimensions $n\geq 4$. In fact, we prove exponential decay, up to a
finite-dimensional space of resonances, of waves valued in any finite rank
subbundle of the tensor bundle, which in particular includes differential forms
and symmetric tensors. As the main technical tool for working on vector bundles
that do not have a natural positive definite inner product, we introduce
pseudodifferential inner products, which are inner products depending on the
position in phase space.",1502.03183v2
2015-07-01,Modulating carrier and sideband coupling strengths in a standing wave gate beam,"We control the relative coupling strength of carrier and first order motional
sideband interactions of a trapped ion by placing it in a resonant optical
standing wave. Our configuration uses the surface of a microfabricated chip
trap as a mirror, avoiding technical challenges of in-vacuum optical cavities.
Displacing the ion along the standing wave, we show a periodic suppression of
the carrier and sideband transitions with the cycles for the two cases
$180^\circ$ out of phase with each other. This technique allows for suppression
of off-resonant carrier excitations when addressing the motional sidebands,
with applications in quantum simulation and quantum control. Using the standing
wave fringes, we measure the relative ion height as a function of applied
electric field, allowing for a precise measurement of ion displacement and,
combined with measured micromotion amplitudes, a validation of trap numerical
models.",1507.00381v2
2015-10-02,Quantum-beat Auger spectroscopy,"The concept of nonlinear quantum-beat pump-probe Auger spectroscopy is
introduced by discussing a relatively simple four-level model system. We
consider a coherent wave packet involving two low-lying states that was
prepared by an appropriate pump pulse. This wave packet is subsequently probed
by a weak, time-delayed probe pulse with nearly resonant coupling to a
core-excited state of the atomic or molecular system. The resonant Auger
spectra are then studied as a function of the duration of the probe pulse and
the time delay. With a bandwidth of the probe pulse approaching the energy
spread of the wave packet, the Auger yields and spectra show quantum beats as a
function of pump-probe delay. An analytic theory for the quantum-beat Auger
spectroscopy will be presented, which allows for the reconstruction of the wave
packet by analyzing the delaydependent Auger spectra. The possibility of
extending this method to a more complex manifold of electronic and vibrational
energy levels is also discussed.",1510.00601v1
2016-06-21,On the $L^p$ boundedness of wave operators for four-dimensional Schrödinger Operators with a threshold eigenvalue,"Let $H=-\Delta+V$ be a Schr\""odinger operator on $L^2(\mathbb R^4)$ with
real-valued potential $V$, and let $H_0=-\Delta$. If $V$ has sufficient
pointwise decay, the wave operators $W_{\pm}=s-\lim_{t\to \pm\infty}
e^{itH}e^{-itH_0}$ are known to be bounded on $L^p(\mathbb R^4)$ for all $1\leq
p\leq \infty$ if zero is not an eigenvalue or resonance, and on $\frac43<p<4$
if zero is an eigenvalue but not a resonance. We show that in the latter case,
the wave operators are also bounded on $L^p(\mathbb R^4)$ for $1\leq p\leq
\frac43$ by direct examination of the integral kernel of the leading terms.
Furthermore, if $\int_{\mathbb R^4} xV(x) \psi(x) \, dx=0$ for all zero energy
eigenfunctions $\psi$, then the wave operators are bounded on $L^p$ for $1 \leq
p<\infty$.",1606.06691v2
2016-07-27,Irreversible Evolution of a Wave Packet in The Rigged Hilbert Space Quantum Mechanics,"It is well known that a state with complex energy cannot be the eigenstate of
a self-adjoint operator, like the Hamiltonian. Resonances, i.e. states with
exponentially decaying observables, are not vectors belonging to the
conventional Hilbert space. One can describe these resonances in an unusual
mathematical formalism, based on the so-called Rigged Hilbert Space (RHS). In
the RHS, the states with complex energy are denoted as Gamow Vectors (GV), and
they model decay processes. We study GV of the Reversed Harmonic Oscillator
(RHO), and we analytically and numerically investigate the unstable evolution
of wave packets. We introduce the background function to study initial data not
composed only by a summation of GV and we analyse different wave packets
belonging to specific function spaces. Our work furnishes support to the idea
that irreversible wave propagations can be investigated by means of Rigged
Hilbert Space Quantum Mechanics and provides insights for the experimental
investigation of irreversible dynamics.",1607.08109v2
2017-12-14,Stealth technology-based Terahertz frequency-domain ellipsometry instrumentation,"We present a terahertz (THz) frequency-domain spectroscopic (FDS)
ellipsometer design which suppresses formation of standing waves by use of
stealth technology approaches. The strategy to suppress standing waves consists
of three elements \textit{geometry}, \textit{coating} and \textit{modulation}.
The instrument is based on the rotating analyzer ellipsometer principle and can
incorporate various sample compartments, such as a superconducting magnet,
\textit{in-situ} gas cells or resonant sample cavities, for example. A backward
wave oscillator and three detectors are employed, which permit operation in the
spectral range of 0.1--1~THz (3.3--33~cm$^{-1}$ or 0.4--4~meV). The THz
frequency-domain ellipsometer allows for standard and generalized ellipsometry
at variable angles of incidence in both reflection and transmission
configurations. The methods used to suppress standing waves and strategies for
an accurate frequency calibration are presented. Experimental results from
dielectric constant determination in anisotropic materials, and free charge
carrier determination in optical Hall effect, resonant-cavity enhanced optical
Hall effect and \textit{in-situ} optical Hall effect experiments are discussed.
Examples include silicon and sapphire optical constants, free charge carrier
properties of two dimensional electron gas in group-III nitride high electron
mobility transistor structure, and ambient effects on free electron mobility
and density in epitaxial graphene.",1712.05283v1
2018-05-07,Bifurcation structure of periodic patterns in the Lugiato-Lefever equation with anomalous dispersion,"We study the stability and bifurcation structure of spatially extended
patterns arising in nonlin- ear optical resonators with a Kerr-type
nonlinearity and anomalous group velocity dispersion, as described by the
Lugiato-Lefever equation. While there exists a one-parameter family of patterns
with different wavelengths, we focus our attention on the pattern with critical
wave number k c arising from the modulational instability of the homogeneous
state. We find that the branch of solutions associated with this pattern
connects to a branch of patterns with wave number $2k_c$ . This next branch
also connects to a branch of patterns with double wave number, this time $4k_c$
, and this process repeats through a series of 2:1 spatial resonances. For
values of the detuning parameter approaching $\theta = 2$ from below the
critical wave number $k_c$ approaches zero and this bifurcation structure is
related to the foliated snaking bifurcation structure organizing spatially
localized bright solitons. Secondary bifurcations that these patterns undergo
and the resulting temporal dynamics are also studied.",1805.02555v1
2019-11-18,Ultra-Efficient Conversion of Microwave into Ultrasound Wave through a Split Ring Resonator,"Thermo-elastic conversion of electromagnetic wave into ultrasound wave has
enabled diverse biomedical applications such as photoacoustic imaging.
Microwave, which has ~10 cm long wavelength, can penetrate deeper into tissue
than photons, heralding exciting applications such as deep tissue imaging via
thermo-acoustic tomography. However, the thermo-acoustic conversion efficiency
is very low even with an exogenous contrast agent such as carbon nanotube.
Here, we break this low conversion limit through using a split ring resonator
(SRR) to effectively collect and concentrate the microwave energy into a
sub-millimeter hot spot and subsequently convert the energy into ultrasound
wave. Our SRR achieves over three orders of magnitude higher thermo-acoustic
conversion efficiency than commonly used thermo-acoustic contrast agents. We
further harness the SRR as a wireless, battery-free ultrasound emitter placed
under a breast phantom. These results promise exciting potential of SRR for
precise thermo-acoustic localization and modulation of subjects in deep tissue.",1911.07887v1
2014-06-06,Damping of quasiparticles in a Bose-Einstein condensate coupled to an optical cavity,"We present a general theory for calculating the damping rate of elementary
density wave excitations in a Bose-Einstein condensate strongly coupled to a
single radiation field mode of an optical cavity. Thereby we give a detailed
derivation of the huge resonant enhancement in the Beliaev damping of a density
wave mode, predicted recently by K\'onya et al., Phys.~Rev.~A 89, 051601(R)
(2014). The given density-wave mode constitutes the polariton-like soft mode of
the self-organization phase transition. The resonant enhancement takes place,
both in the normal and ordered phases, outside the critical region. We show
that the large damping rate is accompanied by a significant frequency shift of
this polariton mode. Going beyond the Born-Markov approximation and determining
the poles of the retarded Green's function of the polariton, we reveal a strong
coupling between the polariton and a collective mode in the phonon bath formed
by the other density wave modes.",1406.1669v1
2020-04-28,Acoustomagnetoelectric effect in two-dimensional materials: Geometric resonances and Weiss oscillations,"We study electron transport in two-dimensional materials with parabolic and
linear (graphene) dispersions of the carriers in the presence of surface
acoustic waves and an external magnetic field using semiclassical Boltzmann
equations approach. We observe an oscillatory behavior of both the longitudinal
and Hall electric currents as functions of the surface acoustic wave frequency
at a fixed magnetic field and as functions of the inverse magnetic field at a
fixed frequency of the acoustic wave. We explain the former by the phenomenon
of geometric resonances, while we relate the latter to the Weiss-like
oscillations in the presence of the dynamic superlattice created by the
acoustic wave. Thus we demonstrate the dual nature of the
acoustomagnetoelectric effect in two-dimensional electron gas.",2004.13275v1
2016-03-07,Ripplon Laser,"Energy exchange between light and sound was first suggested by Brillouin in
1922. After Townes established the phonon maser theory, coherent generation of
intense hypersonic waves was observed together with stimulated Brillouin
Scattering. Here we repeat these experiments, but with capillary-waves that are
unique to the liquid phase of matter and relates to attraction between intimate
fluid particles. We fabricate resonators that co-host capillary and
opticalmodes, control it to operates at its non resolved sideband, and observe
stimulated capillary scattering and coherent excitation of capillary resonances
at kHz rates (that one can hear in audio files recorded by us). By exchanging
energy between electromagnetic and capillary waves, we bridge interfacial
tension phenomena at the liquid phase boundary to optics, and might impact
optofluidics by allowing optical control, interrogation and cooling of water
waves.",1603.02218v2
2016-03-23,Correlations of $\boldsymbol{πN}$ Partial Waves for Multi-Reaction Analyses,"In the search for missing baryonic resonances, many analyses include data
from a variety of pion- and photon-induced reactions. For elastic $\pi N$
scattering, however, usually the partial waves of the SAID or other groups are
fitted, instead of data. We provide the partial-wave covariance matrices needed
to perform correlated $\chi^2$ fits, in which the obtained $\chi^2$ equals the
actual $\chi^2$ up non-linear and normalization corrections. For any analysis
relying on partial waves extracted from elastic pion scattering, this is a
prerequisite to assess the significance of resonance signals and to assign any
uncertainty on results. The influence of systematic errors is also considered.",1603.07265v3
2016-12-13,An estimate of Alpha decay half-life from the poles of S-matrix of an exactly solvable potential,"We develop a versatile and analytically solvable potential which fairly
reproduces the combined potential of an $\alpha+$nucleus system resulting from
both the attractive nuclear and repulsive electrostatic potentials. The
potential is expressed in terms of the radial position, mass and proton number
of the $\alpha$-particle and the daughter nucleus and certain parameters
governing the depth, height and steepness of the barrier. The potential
generated is typically a pocket near the origin and a barrier adjacent to it.
The Schr\""odinger equation with the above mentioned potential is then solved
for the wave function. This potential produces discrete positive energy
quasibound state known as resonance state. By matching the wave function and
its derivative with the regular Coulomb wave function $F_0$ and irregular
Coulomb wave function $G_0$, we obtain the S-matrix analytically. The resonance
is obtained from the pole in complex energy plane which gives the width of the
corresponding time of decay through the imaginary part of the energy pole
position. We make a comparative study of the measured half-lives of various
nuclei with the calculated half-lives. The calculated values of half-lives
closely match with the corresponding experimental results.",1612.04135v1
2017-02-09,Dynamics of the localized nonlinear waves in spin-1 Bose-Einstein condensates with time-space modulation,"We investigate the dynamics of the localized nonlinear matter wave in spin-1
Bose-Einstein condensates with trapping potentials and nonlinearities dependent
on time and space. We solve the three coupled Gross-Pitaevskii equation by
similarity transformation and obtain two families of exact matter wave
solutions in terms of Jacobi elliptic functions and Mathieu equation. The
localized states of the spinor matter wave describe the dynamics of vector
breathing solitons, moving breathing solitons, quasibreathing solitons and
resonant solitons. The results of stability show that one order vector
breathing solitons, quasibreathing solitons, resonant solitons, and the moving
breathing solitons \psi_{\pm1} are all stable but the moving breathing solitons
\psi_0 is unstable. We also present the experimental parameters to realize
these phenomena in the future experiments.",1702.04628v1